Ishikawa K, Nagai Y. Molecular Mechanisms and Future Therapeutics for Spinocerebellar Ataxia Type 31 (SCA31). Neurotherapeutics. 2019 Nov 21. PubMed PMID: 31755042.
From the abstract: "Spinocerebellar ataxia type 31 (SCA31) is one of the autosomal-dominant neurodegenerative disorders that shows progressive cerebellar ataxia as a cardinal symptom. This disease is caused by a 2.5- to 3.8-kb-long complex pentanucleotide repeat containing (TGGAA)n, (TAGAA)n, (TAAAA)n, and (TAAAATAGAA)n in an intron of the gene called BEAN1 (brain expressed, associated with Nedd4). ... To dissect the pathogenesis of (UGGAA)n in SCA31, we generated transgenic fly models of SCA31 by overexpressing SCA31 complex pentanucleotide repeats in Drosophila. We found that the toxicity of (UGGAA)n is length- and expression level-dependent, and it was dampened by co-expressing TDP-43, FUS, and hnRNP A2/B1. ..."
Wednesday, December 4, 2019
Cross-species studies explores mechanisms underlying premature again in Werner syndrome
Fang EF, Hou Y, Lautrup S, Jensen MB, Yang B, SenGupta T, Caponio D, Khezri R, Demarest TG, Aman Y, Figueroa D, Morevati M, Lee HJ, Kato H, Kassahun H, Lee JH, Filippelli D, Okur MN, Mangerich A, Croteau DL, Maezawa Y, Lyssiotis CA, Tao J, Yokote K, Rusten TE, Mattson MP, Jasper H, Nilsen H, Bohr VA. NAD(+) augmentation restores mitophagy and limits accelerated aging in Werner syndrome. Nat Commun. 2019 Nov 21;10(1):5284. PubMed PMID: 31754102; PubMed Central PMCID: PMC6872719.
Abstract: "Metabolic dysfunction is a primary feature of Werner syndrome (WS), a human premature aging disease caused by mutations in the gene encoding the Werner (WRN) DNA helicase. WS patients exhibit severe metabolic phenotypes ... Here we report impaired mitophagy and depletion of ... At the organismal level, NAD+ repletion remarkably extends lifespan and delays accelerated aging, including stem cell dysfunction, in Caenorhabditis elegans and Drosophila melanogaster models of WS. Our findings suggest that accelerated aging in WS is mediated by impaired mitochondrial function and mitophagy, and that bolstering cellular NAD+ levels counteracts WS phenotypes."
Abstract: "Metabolic dysfunction is a primary feature of Werner syndrome (WS), a human premature aging disease caused by mutations in the gene encoding the Werner (WRN) DNA helicase. WS patients exhibit severe metabolic phenotypes ... Here we report impaired mitophagy and depletion of ... At the organismal level, NAD+ repletion remarkably extends lifespan and delays accelerated aging, including stem cell dysfunction, in Caenorhabditis elegans and Drosophila melanogaster models of WS. Our findings suggest that accelerated aging in WS is mediated by impaired mitochondrial function and mitophagy, and that bolstering cellular NAD+ levels counteracts WS phenotypes."
Drosophila studies point to potential relevance of voltage-gated sodium channels in cell proliferation and cancer
Piggott BJ, Peters CJ, He Y, Huang X, Younger S, Jan LY, Jan YN. Paralytic, the Drosophila voltage-gated sodium channel, regulates proliferation of neural progenitors. Genes Dev. 2019 Dec 1;33(23-24):1739-1750. PubMed PMID: 31753914.
From the abstract: "... voltage-gated sodium channels (VGSC) that are crucial for neuronal excitability are also found in progenitors and up-regulated in cancer. Here, we identify a role for VGSC in proliferation of Drosophila neuroblast (NB) lineages within the central nervous system. Loss of paralytic (para), the sole gene that encodes Drosophila VGSC, reduces neuroblast progeny cell number. ... Our data suggests that loss of Para induces apoptosis in this population, whereas overexpression leads to an increase in INPs and overall neuroblast progeny cell numbers. These effects are cell autonomous and depend on Para channel activity. Reduction of Para expression not only affects normal NB development, but also strongly suppresses brain tumor mass, implicating a role for Para in cancer progression. To our knowledge, our studies are the first to identify a role for VGSC in neural progenitor proliferation. Elucidating the contribution of VGSC in proliferation will advance our understanding of bioelectric signaling within development and disease states."
From the abstract: "... voltage-gated sodium channels (VGSC) that are crucial for neuronal excitability are also found in progenitors and up-regulated in cancer. Here, we identify a role for VGSC in proliferation of Drosophila neuroblast (NB) lineages within the central nervous system. Loss of paralytic (para), the sole gene that encodes Drosophila VGSC, reduces neuroblast progeny cell number. ... Our data suggests that loss of Para induces apoptosis in this population, whereas overexpression leads to an increase in INPs and overall neuroblast progeny cell numbers. These effects are cell autonomous and depend on Para channel activity. Reduction of Para expression not only affects normal NB development, but also strongly suppresses brain tumor mass, implicating a role for Para in cancer progression. To our knowledge, our studies are the first to identify a role for VGSC in neural progenitor proliferation. Elucidating the contribution of VGSC in proliferation will advance our understanding of bioelectric signaling within development and disease states."
Studies in Drosophila point to potential therapeutic approach for treatment of Parkinson's Disease based on modulation of kynurenine metabolism
Cunningham PC, Waldeck K, Ganetzky B, Babcock DT. Neurodegeneration and locomotor dysfunction in Drosophila scarlet mutants. J Cell Sci. 2018 Sep 17;131(18). pii: jcs216697. doi: 10.1242/jcs.216697. PubMed PMID: 30154211; PubMed Central PMCID: PMC6176922.
From the abstract: "Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons, resulting in progressive locomotor dysfunction. Identification of genes required for the maintenance of these neurons should help to identify potential therapeutic targets. ... Here, we show that Drosophila melanogaster scarlet mutants exhibit an age-dependent progressive loss of dopaminergic neurons, along with subsequent locomotor defects and a shortened lifespan. ... we show that expression of wild-type Scarlet is neuroprotective in a model of PD, suggesting that manipulating kynurenine metabolism may be a potential therapeutic option in treating PD."
From the abstract: "Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons, resulting in progressive locomotor dysfunction. Identification of genes required for the maintenance of these neurons should help to identify potential therapeutic targets. ... Here, we show that Drosophila melanogaster scarlet mutants exhibit an age-dependent progressive loss of dopaminergic neurons, along with subsequent locomotor defects and a shortened lifespan. ... we show that expression of wild-type Scarlet is neuroprotective in a model of PD, suggesting that manipulating kynurenine metabolism may be a potential therapeutic option in treating PD."
Flies used to explore potential health impacts of a food additive
Jovanović B, Jovanović N, Cvetković VJ, Matić S, Stanić S, Whitley EM, Mitrović TL. The effects of a human food additive, titanium dioxide nanoparticles E171, on Drosophila melanogaster - a 20 generation dietary exposure experiment. Sci Rep. 2018 Dec 18;8(1):17922. PubMed PMID: 30560898; PubMed Central PMCID: PMC6298969.
Abstract: "In this study, fruit flies (Drosophila melanogaster) were exposed to an estimated daily human E171 consumption concentration for 20 generations. Exposure to E171 resulted in: a change in normal developmental and reproductive dynamics, reduced fecundity after repetitive breeding, increased genotoxicity, the appearance of aberrant phenotypes and morphologic changes to the adult fat body. Marks of adaptive evolution and directional selection were also exhibited. The larval stages were at a higher risk of sustaining damage from E171 as they had a slower elimination rate of TiO2 compared to the adults. This is particularly worrisome, since among the human population, children tend to consume higher daily concentrations of E171 than do adults. The genotoxic effect of E171 was statistically higher in each subsequent generation compared to the previous one. Aberrant phenotypes were likely caused by developmental defects induced by E171, and were not mutations, since the phenotypic features were not transferred to any progeny even after 5 generations of consecutive crossbreeding. Therefore, exposure to E171 during the early developmental period carries a higher risk of toxicity. The fact that the daily human consumption concentration of E171 interferes with and influences fruit fly physiological, ontogenetic, genotoxic, and adaptive processes certainly raises safety concerns."
Abstract: "In this study, fruit flies (Drosophila melanogaster) were exposed to an estimated daily human E171 consumption concentration for 20 generations. Exposure to E171 resulted in: a change in normal developmental and reproductive dynamics, reduced fecundity after repetitive breeding, increased genotoxicity, the appearance of aberrant phenotypes and morphologic changes to the adult fat body. Marks of adaptive evolution and directional selection were also exhibited. The larval stages were at a higher risk of sustaining damage from E171 as they had a slower elimination rate of TiO2 compared to the adults. This is particularly worrisome, since among the human population, children tend to consume higher daily concentrations of E171 than do adults. The genotoxic effect of E171 was statistically higher in each subsequent generation compared to the previous one. Aberrant phenotypes were likely caused by developmental defects induced by E171, and were not mutations, since the phenotypic features were not transferred to any progeny even after 5 generations of consecutive crossbreeding. Therefore, exposure to E171 during the early developmental period carries a higher risk of toxicity. The fact that the daily human consumption concentration of E171 interferes with and influences fruit fly physiological, ontogenetic, genotoxic, and adaptive processes certainly raises safety concerns."
Fly studies help provide insights into molecular mechanisms related to Charcot-Marie-Tooth and related disorders
Suda K, Muraoka Y, Ortega-Yáñez A, Yoshida H, Kizu F, Hochin T, Kimura H, Yamaguchi M. Reduction of Rpd3 suppresses defects in locomotive ability and neuronal morphology induced by the knockdown of Drosophila SLC25A46 via an epigenetic pathway. Exp Cell Res. 2019 Dec 15;385(2):111673. PubMed PMID: 31614134.
Abstract: "Mitochondrial dysfunction causes various diseases. Mutations in the SLC25A46 gene have been identified in mitochondrial diseases that are sometimes classified as Charcot-Marie-Tooth disease type 2, optic atrophy, and Leigh syndrome. A homolog of SLC25A46 was identified in Drosophila and designated as dSLC25A46 (CG5755). We previously established mitochondrial disease model targeting of dSLC25A46, which causes locomotive dysfunction and morphological defects at neuromuscular junctions, such as reduced synaptic branch lengths and decreased numbers of boutons. The diverse symptoms of mitochondrial diseases carrying mutations in SLC25A46 may be associated with the dysregulation of some epigenetic regulators. To investigate the involvement of epigenetic regulators in mitochondrial diseases, we examined candidate epigenetic regulators that interact with human SLC25A46 by searching Gene Expression Omnibus (GEO). We discovered that HDAC1 binds to several SLC25A46 genomic regions in human cultured CD4 (+) cells, and attempted to prove this in an in vivo Drosophila model. By demonstrating that Rpd3, Drosophila HDAC1, regulates the histone H4K8 acetylation state in dSLC25A46 genomic regions, we confirmed that Rpd3 is a novel epigenetic regulator modifying the phenotypes observed with the mitochondrial disease model targeting of dSLC25A46. The functional reduction of Rpd3 rescued the deficient locomotive ability and aberrant morphology of motoneurons at presynaptic terminals induced by the dSLC25A46 knockdown. The present results suggest that the inhibition of HDAC1 suppresses the pathogenic processes that lead to the degeneration of motoneurons in mitochondrial diseases."
Abstract: "Mitochondrial dysfunction causes various diseases. Mutations in the SLC25A46 gene have been identified in mitochondrial diseases that are sometimes classified as Charcot-Marie-Tooth disease type 2, optic atrophy, and Leigh syndrome. A homolog of SLC25A46 was identified in Drosophila and designated as dSLC25A46 (CG5755). We previously established mitochondrial disease model targeting of dSLC25A46, which causes locomotive dysfunction and morphological defects at neuromuscular junctions, such as reduced synaptic branch lengths and decreased numbers of boutons. The diverse symptoms of mitochondrial diseases carrying mutations in SLC25A46 may be associated with the dysregulation of some epigenetic regulators. To investigate the involvement of epigenetic regulators in mitochondrial diseases, we examined candidate epigenetic regulators that interact with human SLC25A46 by searching Gene Expression Omnibus (GEO). We discovered that HDAC1 binds to several SLC25A46 genomic regions in human cultured CD4 (+) cells, and attempted to prove this in an in vivo Drosophila model. By demonstrating that Rpd3, Drosophila HDAC1, regulates the histone H4K8 acetylation state in dSLC25A46 genomic regions, we confirmed that Rpd3 is a novel epigenetic regulator modifying the phenotypes observed with the mitochondrial disease model targeting of dSLC25A46. The functional reduction of Rpd3 rescued the deficient locomotive ability and aberrant morphology of motoneurons at presynaptic terminals induced by the dSLC25A46 knockdown. The present results suggest that the inhibition of HDAC1 suppresses the pathogenic processes that lead to the degeneration of motoneurons in mitochondrial diseases."
Cross-species study helps provide insight on the human gene IQSEC1, variants in which are associated with developmental disease
Ansar M, Chung HL, Al-Otaibi A, Elagabani MN, Ravenscroft TA, Paracha SA, Scholz R, Abdel Magid T, Sarwar MT, Shah SF, Qaisar AA, Makrythanasis P, Marcogliese PC, Kamsteeg EJ, Falconnet E, Ranza E, Santoni FA, Aldhalaan H, Al-Asmari A, Faqeih EA, Ahmed J, Kornau HC, Bellen HJ, Antonarakis SE. Bi-allelic Variants in IQSEC1 Cause Intellectual Disability, Developmental Delay, and Short Stature. Am J Hum Genet. 2019 Nov 7;105(5):907-920. PubMed PMID: 31607425; PubMed Central PMCID: PMC6848997.
From the abstract: "We report two consanguineous families with probands that exhibit intellectual disability, developmental delay, short stature, aphasia, and hypotonia in which homozygous non-synonymous variants were identified in IQSEC1 (GenBank: NM_001134382.3). ... IQSEC1-3 encode guanine nucleotide exchange factors for the small GTPase ARF6 and their loss affects a variety of actin-dependent cellular processes, including AMPA receptor trafficking at synapses. The ortholog of IQSECs in the fly is schizo and its loss affects growth cone guidance at the midline in the CNS, also an actin-dependent process. Overexpression of the reference IQSEC1 cDNA in wild-type flies is lethal, but overexpression of the two variant IQSEC1 cDNAs did not affect viability. Loss of schizo caused embryonic lethality that could be rescued to 2nd instar larvae by moderate expression of the human reference cDNA. However, the p.Arg321Gln and p.Thr343Met variants failed to rescue embryonic lethality. These data indicate that the variants behave as loss-of-function mutations. We also show that schizo in photoreceptors is required for phototransduction. Finally, mice with a conditional Iqsec1 deletion in cortical neurons exhibited an increased density of dendritic spines with an immature morphology. The phenotypic similarity of the affecteds and the functional experiments in flies and mice indicate that IQSEC1 variants are the cause of a recessive disease with intellectual disability, developmental delay, and short stature, and that axonal guidance and dendritic projection defects as well as dendritic spine dysgenesis may underlie disease pathogenesis."
From the abstract: "We report two consanguineous families with probands that exhibit intellectual disability, developmental delay, short stature, aphasia, and hypotonia in which homozygous non-synonymous variants were identified in IQSEC1 (GenBank: NM_001134382.3). ... IQSEC1-3 encode guanine nucleotide exchange factors for the small GTPase ARF6 and their loss affects a variety of actin-dependent cellular processes, including AMPA receptor trafficking at synapses. The ortholog of IQSECs in the fly is schizo and its loss affects growth cone guidance at the midline in the CNS, also an actin-dependent process. Overexpression of the reference IQSEC1 cDNA in wild-type flies is lethal, but overexpression of the two variant IQSEC1 cDNAs did not affect viability. Loss of schizo caused embryonic lethality that could be rescued to 2nd instar larvae by moderate expression of the human reference cDNA. However, the p.Arg321Gln and p.Thr343Met variants failed to rescue embryonic lethality. These data indicate that the variants behave as loss-of-function mutations. We also show that schizo in photoreceptors is required for phototransduction. Finally, mice with a conditional Iqsec1 deletion in cortical neurons exhibited an increased density of dendritic spines with an immature morphology. The phenotypic similarity of the affecteds and the functional experiments in flies and mice indicate that IQSEC1 variants are the cause of a recessive disease with intellectual disability, developmental delay, and short stature, and that axonal guidance and dendritic projection defects as well as dendritic spine dysgenesis may underlie disease pathogenesis."
Variant forms of human MYH9 introduced into flies as part of study related to understanding muscle-related diseases
Kasza KE, Supriyatno S, Zallen JA. Cellular defects resulting from disease-related myosin II mutations in Drosophila. Proc Natl Acad Sci U S A. 2019 Oct 29;116(44):22205-22211. doi: 10.1073/pnas.1909227116. Epub 2019 Oct 15. PubMed PMID: 31615886; PubMed Central PMCID: PMC6825282.
Abstract: "The nonmuscle myosin II motor protein produces forces that are essential to driving the cell movements and cell shape changes that generate tissue structure. Mutations in myosin II that are associated with human diseases are predicted to disrupt critical aspects of myosin function, but the mechanisms that translate altered myosin activity into specific changes in tissue organization and physiology are not well understood. Here we use the Drosophila embryo to model human disease mutations that affect myosin motor activity. Using in vivo imaging and biophysical analysis, we show that engineering human MYH9-related disease mutations into Drosophila myosin II produces motors with altered organization and dynamics that fail to drive rapid cell movements, resulting in defects in epithelial morphogenesis. In embryos that express the Drosophila myosin motor variants R707C or N98K and have reduced levels of wild-type myosin, myosin motors are correctly planar polarized and generate anisotropic contractile tension in the tissue. However, expression of these motor variants is associated with a cellular-scale reduction in the speed of cell intercalation, resulting in a failure to promote full elongation of the body axis. In addition, these myosin motor variants display slowed turnover and aberrant aggregation at the cell cortex, indicating that mutations in the motor domain influence mesoscale properties of myosin organization and dynamics. These results demonstrate that disease-associated mutations in the myosin II motor domain disrupt specific aspects of myosin localization and activity during cell intercalation, linking molecular changes in myosin activity to defects in tissue morphogenesis."
Abstract: "The nonmuscle myosin II motor protein produces forces that are essential to driving the cell movements and cell shape changes that generate tissue structure. Mutations in myosin II that are associated with human diseases are predicted to disrupt critical aspects of myosin function, but the mechanisms that translate altered myosin activity into specific changes in tissue organization and physiology are not well understood. Here we use the Drosophila embryo to model human disease mutations that affect myosin motor activity. Using in vivo imaging and biophysical analysis, we show that engineering human MYH9-related disease mutations into Drosophila myosin II produces motors with altered organization and dynamics that fail to drive rapid cell movements, resulting in defects in epithelial morphogenesis. In embryos that express the Drosophila myosin motor variants R707C or N98K and have reduced levels of wild-type myosin, myosin motors are correctly planar polarized and generate anisotropic contractile tension in the tissue. However, expression of these motor variants is associated with a cellular-scale reduction in the speed of cell intercalation, resulting in a failure to promote full elongation of the body axis. In addition, these myosin motor variants display slowed turnover and aberrant aggregation at the cell cortex, indicating that mutations in the motor domain influence mesoscale properties of myosin organization and dynamics. These results demonstrate that disease-associated mutations in the myosin II motor domain disrupt specific aspects of myosin localization and activity during cell intercalation, linking molecular changes in myosin activity to defects in tissue morphogenesis."
Disruption of MARK3 ortholog in flies helps establish "a new gene-disease link" related to visual impairment
Ansar M, Chung H, Waryah YM, Makrythanasis P, Falconnet E, Rao AR, Guipponi M Narsani AK, Fingerhut R, Santoni FA, Ranza E, Waryah AM, Bellen HJ, Antonarakis SE. Visual impairment and progressive phthisis bulbi caused by recessive pathogenic variant in MARK3. Hum Mol Genet. 2018 Aug 1;27(15):2703-2711. PubMed PMID: 29771303; PubMed Central PMCID: PMC6048992.
Abstract: "Developmental eye defects often severely reduce vision. Despite extensive efforts, for a substantial fraction of these cases the molecular causes are unknown. Recessive eye disorders are frequent in consanguineous populations and such large families with multiple affected individuals provide an opportunity to identify recessive causative genes. We studied a Pakistani consanguineous family with three affected individuals with congenital vision loss and progressive eye degeneration. The family was analyzed by exome sequencing of one affected individual and genotyping of all family members. We have identified a non-synonymous homozygous variant (NM_001128918.2: c.1708C > G: p.Arg570Gly) in the MARK3 gene as the likely cause of the phenotype. Given that MARK3 is highly conserved in flies (I: 55%; S: 67%) we knocked down the MARK3 homologue, par-1, in the eye during development. This leads to a significant reduction in eye size, a severe loss of photoreceptors and loss of vision based on electroretinogram (ERG) recordings. Expression of the par-1 p.Arg792Gly mutation (equivalent to the MARK3 variant found in patients) in developing fly eyes also induces loss of eye tissue and reduces the ERG signals. The data in flies and human indicate that the MARK3 variant corresponds to a loss of function. We conclude that the identified mutation in MARK3 establishes a new gene-disease link, since it likely causes structural abnormalities during eye development and visual impairment in humans, and that the function of MARK3/par-1 is evolutionarily conserved in eye development."
Abstract: "Developmental eye defects often severely reduce vision. Despite extensive efforts, for a substantial fraction of these cases the molecular causes are unknown. Recessive eye disorders are frequent in consanguineous populations and such large families with multiple affected individuals provide an opportunity to identify recessive causative genes. We studied a Pakistani consanguineous family with three affected individuals with congenital vision loss and progressive eye degeneration. The family was analyzed by exome sequencing of one affected individual and genotyping of all family members. We have identified a non-synonymous homozygous variant (NM_001128918.2: c.1708C > G: p.Arg570Gly) in the MARK3 gene as the likely cause of the phenotype. Given that MARK3 is highly conserved in flies (I: 55%; S: 67%) we knocked down the MARK3 homologue, par-1, in the eye during development. This leads to a significant reduction in eye size, a severe loss of photoreceptors and loss of vision based on electroretinogram (ERG) recordings. Expression of the par-1 p.Arg792Gly mutation (equivalent to the MARK3 variant found in patients) in developing fly eyes also induces loss of eye tissue and reduces the ERG signals. The data in flies and human indicate that the MARK3 variant corresponds to a loss of function. We conclude that the identified mutation in MARK3 establishes a new gene-disease link, since it likely causes structural abnormalities during eye development and visual impairment in humans, and that the function of MARK3/par-1 is evolutionarily conserved in eye development."
PubMedCentral: Fly model used in studies related to ALS and FTLD
Wang P, Deng J, Dong J, Liu J, Bigio EH, Mesulam M, Wang T, Sun L, Wang L, Lee AY, McGee WA, Chen X, Fushimi K, Zhu L, Wu JY. TDP-43 induces mitochondrial damage and activates the mitochondrial unfolded protein response. PLoS Genet. 2019 May 17;15(5):e1007947. PubMed PMID: 31100073; PubMed Central PMCID: PMC6524796.
From the abstract: "Mutations in or dys-regulation of the TDP-43 gene have been associated with TDP-43 proteinopathy, a spectrum of neurodegenerative diseases including Frontotemporal Lobar Degeneration (FTLD) and Amyotrophic Lateral Sclerosis (ALS). The underlying molecular and cellular defects, however, remain unclear. Here, we report a systematic study combining analyses of patient brain samples with cellular and animal models for TDP-43 proteinopathy. ... Our work has not only uncovered a previously unknown role of LonP1 in regulating mitochondrial TDP-43 levels, but also advanced our understanding of the pathogenic mechanisms for TDP-43 proteinopathy. Our study suggests that blocking or reversing mitochondrial damage may provide a potential therapeutic approach to these devastating diseases."
Bogaert E, Boeynaems S, Kato M, Guo L, Caulfield TR, Steyaert J, Scheveneels W, Wilmans N, Haeck W, Hersmus N, Schymkowitz J, Rousseau F, Shorter J, Callaerts P, Robberecht W, Van Damme P, Van Den Bosch L. Molecular Dissection of FUS Points at Synergistic Effect of Low-Complexity Domains in Toxicity. Cell Rep. 2018 Jul 17;24(3):529-537.e4. PubMed PMID: 30021151; PubMed Central PMCID: PMC6077250.
Abstract: "RNA-binding protein aggregation is a pathological hallmark of several neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). To gain better insight into the molecular interactions underlying this process, we investigated FUS, which is mutated and aggregated in both ALS and FTLD. We generated a Drosophila model of FUS toxicity and identified a previously unrecognized synergistic effect between the N-terminal prion-like domain and the C-terminal arginine-rich domain to mediate toxicity. Although the prion-like domain is generally considered to mediate aggregation of FUS, we find that arginine residues in the C-terminal low-complexity domain are also required for maturation of FUS in cellular stress granules. These data highlight an important role for arginine-rich domains in the pathology of RNA-binding proteins."
From the abstract: "Mutations in or dys-regulation of the TDP-43 gene have been associated with TDP-43 proteinopathy, a spectrum of neurodegenerative diseases including Frontotemporal Lobar Degeneration (FTLD) and Amyotrophic Lateral Sclerosis (ALS). The underlying molecular and cellular defects, however, remain unclear. Here, we report a systematic study combining analyses of patient brain samples with cellular and animal models for TDP-43 proteinopathy. ... Our work has not only uncovered a previously unknown role of LonP1 in regulating mitochondrial TDP-43 levels, but also advanced our understanding of the pathogenic mechanisms for TDP-43 proteinopathy. Our study suggests that blocking or reversing mitochondrial damage may provide a potential therapeutic approach to these devastating diseases."
Bogaert E, Boeynaems S, Kato M, Guo L, Caulfield TR, Steyaert J, Scheveneels W, Wilmans N, Haeck W, Hersmus N, Schymkowitz J, Rousseau F, Shorter J, Callaerts P, Robberecht W, Van Damme P, Van Den Bosch L. Molecular Dissection of FUS Points at Synergistic Effect of Low-Complexity Domains in Toxicity. Cell Rep. 2018 Jul 17;24(3):529-537.e4. PubMed PMID: 30021151; PubMed Central PMCID: PMC6077250.
Abstract: "RNA-binding protein aggregation is a pathological hallmark of several neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). To gain better insight into the molecular interactions underlying this process, we investigated FUS, which is mutated and aggregated in both ALS and FTLD. We generated a Drosophila model of FUS toxicity and identified a previously unrecognized synergistic effect between the N-terminal prion-like domain and the C-terminal arginine-rich domain to mediate toxicity. Although the prion-like domain is generally considered to mediate aggregation of FUS, we find that arginine residues in the C-terminal low-complexity domain are also required for maturation of FUS in cellular stress granules. These data highlight an important role for arginine-rich domains in the pathology of RNA-binding proteins."
Monday, December 2, 2019
Fly studies contribute to new report of an early-onset autosomal-recessive neurological disease
Wang J, Rousseau J, Kim E, Ehresmann S, Cheng YT, Duraine L, Zuo Z, Park YJ, Li-Kroeger D, Bi W, Wong LJ, Rosenfeld J, Gleeson J, Faqeih E, Alkuraya FS, Wierenga KJ, Chen J, Afenjar A, Nava C, Doummar D, Keren B, Juusola J, Grompe M, Bellen HJ, Campeau PM. Loss of Oxidation Resistance 1, OXR1, Is Associated with an Autosomal-Recessive Neurological Disease with Cerebellar Atrophy and Lysosomal Dysfunction. Am J Hum Genet. 2019 Nov 25. pii: S0002-9297(19)30423-9. PubMed PMID: 31785787.
Abstract: "We report an early-onset autosomal-recessive neurological disease with cerebellar atrophy and lysosomal dysfunction. We identified bi-allelic loss-of-function (LoF) variants in Oxidative Resistance 1 (OXR1) in five individuals from three families; these individuals presented with a history of severe global developmental delay, current intellectual disability, language delay, cerebellar atrophy, and seizures. While OXR1 is known to play a role in oxidative stress resistance, its molecular functions are not well established. OXR1 contains three conserved domains: LysM, GRAM, and TLDc. The gene encodes at least six transcripts, including some that only consist of the C-terminal TLDc domain. We utilized Drosophila to assess the phenotypes associated with loss of mustard (mtd), the fly homolog of OXR1. Strong LoF mutants exhibit late pupal lethality or pupal eclosion defects. Interestingly, although mtd encodes 26 transcripts, severe LoF and null mutations can be rescued by a single short human OXR1 cDNA that only contains the TLDc domain. Similar rescue is observed with the TLDc domain of NCOA7, another human homolog of mtd. Loss of mtd in neurons leads to massive cell loss, early death, and an accumulation of aberrant lysosomal structures, similar to what we observe in fibroblasts of affected individuals. Our data indicate that mtd and OXR1 are required for proper lysosomal function; this is consistent with observations that NCOA7 is required for lysosomal acidification."
Abstract: "We report an early-onset autosomal-recessive neurological disease with cerebellar atrophy and lysosomal dysfunction. We identified bi-allelic loss-of-function (LoF) variants in Oxidative Resistance 1 (OXR1) in five individuals from three families; these individuals presented with a history of severe global developmental delay, current intellectual disability, language delay, cerebellar atrophy, and seizures. While OXR1 is known to play a role in oxidative stress resistance, its molecular functions are not well established. OXR1 contains three conserved domains: LysM, GRAM, and TLDc. The gene encodes at least six transcripts, including some that only consist of the C-terminal TLDc domain. We utilized Drosophila to assess the phenotypes associated with loss of mustard (mtd), the fly homolog of OXR1. Strong LoF mutants exhibit late pupal lethality or pupal eclosion defects. Interestingly, although mtd encodes 26 transcripts, severe LoF and null mutations can be rescued by a single short human OXR1 cDNA that only contains the TLDc domain. Similar rescue is observed with the TLDc domain of NCOA7, another human homolog of mtd. Loss of mtd in neurons leads to massive cell loss, early death, and an accumulation of aberrant lysosomal structures, similar to what we observe in fibroblasts of affected individuals. Our data indicate that mtd and OXR1 are required for proper lysosomal function; this is consistent with observations that NCOA7 is required for lysosomal acidification."
Wangler et al describe "valuable platform to discover genes potentially involved in dominant disease that could affect peroxisomes"
Graves HK, Jangam S, Tan KL, Pignata A, Seto ES, Yamamoto S, Wangler MF. A Genetic Screen for Genes That Impact Peroxisomes in Drosophila Identifies Candidate Genes for Human Disease. G3 (Bethesda). 2019 Nov 25. pii: g3.400803.2019. PMID: 31767637.
From the abstract: "Peroxisomes are subcellular organelles that are essential for proper function of eukaryotic cells. In addition to being the sites of a variety of oxidative reactions, they are crucial regulators of lipid metabolism. Peroxisome loss or dysfunction leads to multi-system diseases in humans that strongly affect the nervous system. In order to identify previously unidentified genes and mechanisms that impact peroxisomes, we conducted a genetic screen ... Using the number, size and morphology of GFP tagged peroxisomes as a readout, we screened for mutations that altered peroxisomes ... we identified eighteen genes that cause increases in peroxisome number or altered morphology when mutated. We examined the human homologs of these genes and found that they are involved in a diverse array of cellular processes. Interestingly, the human homologs ... are good candidate genes particularly for dominant genetic disease. This in vivo screening approach for peroxisome defects allows identification of novel genes that impact peroxisomes ... and is a valuable platform to discover genes potentially involved in dominant disease that could affect peroxisomes."
From the abstract: "Peroxisomes are subcellular organelles that are essential for proper function of eukaryotic cells. In addition to being the sites of a variety of oxidative reactions, they are crucial regulators of lipid metabolism. Peroxisome loss or dysfunction leads to multi-system diseases in humans that strongly affect the nervous system. In order to identify previously unidentified genes and mechanisms that impact peroxisomes, we conducted a genetic screen ... Using the number, size and morphology of GFP tagged peroxisomes as a readout, we screened for mutations that altered peroxisomes ... we identified eighteen genes that cause increases in peroxisome number or altered morphology when mutated. We examined the human homologs of these genes and found that they are involved in a diverse array of cellular processes. Interestingly, the human homologs ... are good candidate genes particularly for dominant genetic disease. This in vivo screening approach for peroxisome defects allows identification of novel genes that impact peroxisomes ... and is a valuable platform to discover genes potentially involved in dominant disease that could affect peroxisomes."
Drosophila model of amyloid-beta aggregation used in study that helps inform mechanistic understanding related to Alzheimer's disease
Stapper ZA, Jahn TR. Changes in Glutathione Redox Potential Are Linked to Aβ(42)-Induced Neurotoxicity. Cell Rep. 2018 Aug 14;24(7):1696-1703. PMID: 30110626.
Abstract: "Glutathione is the major low-molecular weight thiol of eukaryotic cells. It is central to one of the two major NADPH-dependent reducing systems and is likely to play a role in combating oxidative stress, a process suggested to play a key role in Alzheimer's disease (AD). However, the nature and relevance of redox changes in the onset and progression of AD are still uncertain. Here, we combine genetically encoded redox sensors with our Drosophila models of amyloid-beta (Aβ) aggregation. We find that changes in glutathione redox potential (EGSH) closely correlate with disease onset and progression. We observe this redox imbalance specifically in neurons, but not in glia cells. EGSH changes and Aβ42 deposition are also accompanied by increased JNK stress signaling. Furthermore, pharmacologic and genetic manipulation of glutathione synthesis modulates Aβ42-mediated neurotoxicity, suggesting a causal relationship between disturbed glutathione redox homeostasis and early AD pathology."
Abstract: "Glutathione is the major low-molecular weight thiol of eukaryotic cells. It is central to one of the two major NADPH-dependent reducing systems and is likely to play a role in combating oxidative stress, a process suggested to play a key role in Alzheimer's disease (AD). However, the nature and relevance of redox changes in the onset and progression of AD are still uncertain. Here, we combine genetically encoded redox sensors with our Drosophila models of amyloid-beta (Aβ) aggregation. We find that changes in glutathione redox potential (EGSH) closely correlate with disease onset and progression. We observe this redox imbalance specifically in neurons, but not in glia cells. EGSH changes and Aβ42 deposition are also accompanied by increased JNK stress signaling. Furthermore, pharmacologic and genetic manipulation of glutathione synthesis modulates Aβ42-mediated neurotoxicity, suggesting a causal relationship between disturbed glutathione redox homeostasis and early AD pathology."
Drosophila model used to explore mechanisms related to Alzheimer's disease
Zhuang L, Peng F, Huang Y, Li W, Huang J, Chu Y, Ren P, Sun Y, Zhang Y, Xue E, Guo X, Shen X, Xue L. CHIP modulates APP-induced autophagy-dependent pathological symptoms in Drosophila. Aging Cell. 2019 Nov 28:e13070. PubMed PMID: 31777182.
Abstract: "Dysregulation of autophagy is associated with the neurodegenerative processes in Alzheimer's disease (AD), yet it remains controversial whether autophagy is a cause or consequence of AD. We have previously expressed the full-length human APP in Drosophila and established a fly AD model that exhibits multiple AD-like symptoms. Here we report that depletion of CHIP effectively palliated APP-induced pathological symptoms, including morphological, behavioral, and cognitive defects. Mechanistically, CHIP is required for APP-induced autophagy dysfunction, which promotes Aβ production via increased expression of BACE and Psn. Our findings suggest that aberrant autophagy is not only a consequence of abnormal APP activity, but also contributes to dysregulated APP metabolism and subsequent AD pathogenesis."
Abstract: "Dysregulation of autophagy is associated with the neurodegenerative processes in Alzheimer's disease (AD), yet it remains controversial whether autophagy is a cause or consequence of AD. We have previously expressed the full-length human APP in Drosophila and established a fly AD model that exhibits multiple AD-like symptoms. Here we report that depletion of CHIP effectively palliated APP-induced pathological symptoms, including morphological, behavioral, and cognitive defects. Mechanistically, CHIP is required for APP-induced autophagy dysfunction, which promotes Aβ production via increased expression of BACE and Psn. Our findings suggest that aberrant autophagy is not only a consequence of abnormal APP activity, but also contributes to dysregulated APP metabolism and subsequent AD pathogenesis."
Drosophila model reveals mechanistic insights into the human disease-associated gene PNPLA6 and disease-associated variants
Sunderhaus ER, Law AD, Kretzschmar D. Disease-Associated PNPLA6 Mutations Maintain Partial Functions When Analyzed in Drosophila. Front Neurosci. 2019 Nov 6;13:1207. PMID:
31780887; PMCID: PMC6852622.
From the abstract: "Mutations in patatin-like phospholipase domain-containing protein 6 (PNPLA6) have been linked with a number of inherited diseases with clinical symptoms that include spastic paraplegia, ataxia, and chorioretinal dystrophy. PNPLA6 is an evolutionary conserved protein whose ortholog in Drosophila is Swiss-Cheese (SWS). ... disease-causing point mutations are found in homozygous patients, with some localized in the phospholipase domain while others are in a region that contains several cNMP binding sites. To investigate how different mutations affect the function of PNPLA6 in an in vivo model, we expressed them in the Drosophila sws1 null mutant. Expressing wild-type PNPLA6 suppressed the locomotion and degenerative phenotypes in sws 1 and restored lipid levels, confirming that the human protein can replace fly SWS. In contrast, none of the mutant proteins restored lipid levels, although they suppressed the behavioral and degenerative phenotypes, at least in early stages. These results show that these mutant forms of PNPLA6 retain some biological function, indicating that disruption of lipid homeostasis is only part of the pathogenic mechanism. ..."
31780887; PMCID: PMC6852622.
From the abstract: "Mutations in patatin-like phospholipase domain-containing protein 6 (PNPLA6) have been linked with a number of inherited diseases with clinical symptoms that include spastic paraplegia, ataxia, and chorioretinal dystrophy. PNPLA6 is an evolutionary conserved protein whose ortholog in Drosophila is Swiss-Cheese (SWS). ... disease-causing point mutations are found in homozygous patients, with some localized in the phospholipase domain while others are in a region that contains several cNMP binding sites. To investigate how different mutations affect the function of PNPLA6 in an in vivo model, we expressed them in the Drosophila sws1 null mutant. Expressing wild-type PNPLA6 suppressed the locomotion and degenerative phenotypes in sws 1 and restored lipid levels, confirming that the human protein can replace fly SWS. In contrast, none of the mutant proteins restored lipid levels, although they suppressed the behavioral and degenerative phenotypes, at least in early stages. These results show that these mutant forms of PNPLA6 retain some biological function, indicating that disruption of lipid homeostasis is only part of the pathogenic mechanism. ..."
Drosophila model of Spinocerebellar Ataxia type 3 used as part of an effort to identify drug targets for treatment of this ataxia
Ashraf NS, Sutton JR, Yang Y, Ranxhi B, Libohova K, Shaw ED, Barget AJ, Todi SV, Paulson HL, do Carmo Costa M. Druggable genome screen identifies new regulators of the abundance and toxicity of ATXN3, the Spinocerebellar Ataxia type 3 disease protein. Neurobiol Dis. 2019 Nov 26:104697. PMID: 31783119.
From the abstract: "Spinocerebellar Ataxia type 3 (SCA3, also known as Machado-Joseph disease) is a neurodegenerative disorder ... No preventive treatment is yet available for SCA3. ... Here, we sought to identify genes that modulate ATXN3 levels as potential therapeutic targets in this fatal disorder. We screened a collection of siRNAs targeting 2742 druggable human genes using a cell-based assay ... Among the 33 genes confirmed in secondary assays, 15 were validated in an independent cell model as modulators of pathogenic ATXN3 protein levels. Ten of these genes were then assessed in a Drosophila model of SCA3, and one was confirmed as a key modulator of physiological ATXN3 abundance in SCA3 neuronal progenitor cells. ... Among identified pathways highlighted by this screen, the FBXL3/SCF axis represents a novel molecular pathway that regulates physiological levels of ATXN3 protein."
From the abstract: "Spinocerebellar Ataxia type 3 (SCA3, also known as Machado-Joseph disease) is a neurodegenerative disorder ... No preventive treatment is yet available for SCA3. ... Here, we sought to identify genes that modulate ATXN3 levels as potential therapeutic targets in this fatal disorder. We screened a collection of siRNAs targeting 2742 druggable human genes using a cell-based assay ... Among the 33 genes confirmed in secondary assays, 15 were validated in an independent cell model as modulators of pathogenic ATXN3 protein levels. Ten of these genes were then assessed in a Drosophila model of SCA3, and one was confirmed as a key modulator of physiological ATXN3 abundance in SCA3 neuronal progenitor cells. ... Among identified pathways highlighted by this screen, the FBXL3/SCF axis represents a novel molecular pathway that regulates physiological levels of ATXN3 protein."
Review article highlights relevance of Drosophila for study of human disorders of glycosylation
Nishihara S. Functional analysis of glycosylation using Drosophila melanogaster. Glycoconj J. 2019 Nov 26. doi: 10.1007/s10719-019-09892-0. PMID: 31773367.
From the abstract: "The glycosylation of proteins and lipids has various essential roles in a diverse range of biological processes ... detailed studies with Drosophila mutants of glycosyltransferases, nucleotide sugar transporters, and glycosidases revealed novel functions of N-linked glycans, glycosaminoglycans, glycolipids, and O-linked glycans including mucin type O-glycan, O-Fuc, O-Man, and O-GlcNAc. As many of these functions are common between Drosophila and humans, these mutants represent good models for human disease. In this review, recent studies of glycan functions using Drosophila are summarized."
From the abstract: "The glycosylation of proteins and lipids has various essential roles in a diverse range of biological processes ... detailed studies with Drosophila mutants of glycosyltransferases, nucleotide sugar transporters, and glycosidases revealed novel functions of N-linked glycans, glycosaminoglycans, glycolipids, and O-linked glycans including mucin type O-glycan, O-Fuc, O-Man, and O-GlcNAc. As many of these functions are common between Drosophila and humans, these mutants represent good models for human disease. In this review, recent studies of glycan functions using Drosophila are summarized."
Drosophila study suggests additional molecular function for a gene related to a human disease gene associated with glycogen storage disorder type IV
Huynh N, Ou Q, Cox P, Lill R, King-Jones K. Glycogen branching enzyme controls cellular iron homeostasis via Iron Regulatory Protein 1 and mitoNEET. Nat Commun. 2019 Nov 29;10(1):5463. PMID: 31784520.
Abstract: "Iron Regulatory Protein 1 (IRP1) is a bifunctional cytosolic iron sensor. When iron levels are normal, IRP1 harbours an iron-sulphur cluster (holo-IRP1), an enzyme with aconitase activity. When iron levels fall, IRP1 loses the cluster (apo-IRP1) and binds to iron-responsive elements (IREs) in messenger RNAs (mRNAs) encoding proteins involved in cellular iron uptake, distribution, and storage. Here we show that mutations in the Drosophila 1,4-Alpha-Glucan Branching Enzyme (AGBE) gene cause porphyria. AGBE was hitherto only linked to glycogen metabolism and a fatal human disorder known as glycogen storage disease type IV. AGBE binds specifically to holo-IRP1 and to mitoNEET, a protein capable of repairing IRP1 iron-sulphur clusters. This interaction ensures nuclear translocation of holo-IRP1 and downregulation of iron-dependent processes, demonstrating that holo-IRP1 functions not just as an aconitase, but throttles target gene expression in anticipation of declining iron requirements."
Abstract: "Iron Regulatory Protein 1 (IRP1) is a bifunctional cytosolic iron sensor. When iron levels are normal, IRP1 harbours an iron-sulphur cluster (holo-IRP1), an enzyme with aconitase activity. When iron levels fall, IRP1 loses the cluster (apo-IRP1) and binds to iron-responsive elements (IREs) in messenger RNAs (mRNAs) encoding proteins involved in cellular iron uptake, distribution, and storage. Here we show that mutations in the Drosophila 1,4-Alpha-Glucan Branching Enzyme (AGBE) gene cause porphyria. AGBE was hitherto only linked to glycogen metabolism and a fatal human disorder known as glycogen storage disease type IV. AGBE binds specifically to holo-IRP1 and to mitoNEET, a protein capable of repairing IRP1 iron-sulphur clusters. This interaction ensures nuclear translocation of holo-IRP1 and downregulation of iron-dependent processes, demonstrating that holo-IRP1 functions not just as an aconitase, but throttles target gene expression in anticipation of declining iron requirements."
Monday, November 18, 2019
Drosophila study contributes to understanding molecular mechanisms related to Zika virus-associated microcephaly
Mutations in ANKLE2, a ZIKA Virus Target, Disrupt an Asymmetric Cell Division Pathway in Drosophila Neuroblasts to Cause Microcephaly
Nichole Link, Hyunglok Chung, Angad Jolly, Ghayda M. Mirzaa, James R. Lupski, Hugo J. Bellen
Published:November 14, 2019
DOI:https://doi.org/10.1016/j.devcel.2019.10.009
Summary: "The apical Par complex, which contains atypical protein kinase C (aPKC), Bazooka (Par-3), and Par-6, is required for establishing polarity during asymmetric division of neuroblasts in Drosophila, and its activity depends on L(2)gl. We show that loss of Ankle2, a protein associated with microcephaly in humans and known to interact with Zika protein NS4A, reduces brain volume in flies and impacts the function of the Par complex. Reducing Ankle2 levels disrupts endoplasmic reticulum (ER) and nuclear envelope morphology, releasing the kinase Ballchen-VRK1 into the cytosol. These defects are associated with reduced phosphorylation of aPKC, disruption of Par-complex localization, and spindle alignment defects. Importantly, removal of one copy of ballchen or l(2)gl suppresses Ankle2 mutant phenotypes and restores viability and brain size. Human mutational studies implicate the above-mentioned genes in microcephaly and motor neuron disease. We suggest that NS4A, ANKLE2, VRK1, and LLGL1 define a pathway impinging on asymmetric determinants of neural stem cell division."
Nichole Link, Hyunglok Chung, Angad Jolly, Ghayda M. Mirzaa, James R. Lupski, Hugo J. Bellen
Published:November 14, 2019
DOI:https://doi.org/10.1016/j.devcel.2019.10.009
Summary: "The apical Par complex, which contains atypical protein kinase C (aPKC), Bazooka (Par-3), and Par-6, is required for establishing polarity during asymmetric division of neuroblasts in Drosophila, and its activity depends on L(2)gl. We show that loss of Ankle2, a protein associated with microcephaly in humans and known to interact with Zika protein NS4A, reduces brain volume in flies and impacts the function of the Par complex. Reducing Ankle2 levels disrupts endoplasmic reticulum (ER) and nuclear envelope morphology, releasing the kinase Ballchen-VRK1 into the cytosol. These defects are associated with reduced phosphorylation of aPKC, disruption of Par-complex localization, and spindle alignment defects. Importantly, removal of one copy of ballchen or l(2)gl suppresses Ankle2 mutant phenotypes and restores viability and brain size. Human mutational studies implicate the above-mentioned genes in microcephaly and motor neuron disease. We suggest that NS4A, ANKLE2, VRK1, and LLGL1 define a pathway impinging on asymmetric determinants of neural stem cell division."
Fly studies contribute to understanding of novel monogenic cause of steroid-resistance nephrotic syndrome
Kampf LL, Schneider R, Gerstner L, Thünauer R, Chen M, Helmstädter M, Amar A, Onuchic-Whitford AC, Loza Munarriz R, Berdeli A, Müller D, Schrezenmeier E, Budde K, Mane S, Laricchia KM, Rehm HL, MacArthur DG, Lifton RP, Walz G, Römer W, Bergmann C, Hildebrandt F, Hermle T. TBC1D8B Mutations Implicate RAB11-Dependent Vesicular Trafficking in the Pathogenesis of Nephrotic Syndrome. J Am Soc Nephrol. 2019 Nov 15. pii: ASN.2019040414. doi: 10.1681/ASN.2019040414. PMID: 31732614.
From the abstract: "Mutations in about 50 genes have been identified as monogenic causes of nephrotic syndrome, a frequent cause of CKD. ... We used whole-exome sequencing to identify novel monogenic causes of steroid-resistant nephrotic syndrome (SRNS). We analyzed the functional significance of an SRNS-associated gene in vitro and in podocyte-like Drosophila nephrocytes ..."
From the abstract: "Mutations in about 50 genes have been identified as monogenic causes of nephrotic syndrome, a frequent cause of CKD. ... We used whole-exome sequencing to identify novel monogenic causes of steroid-resistant nephrotic syndrome (SRNS). We analyzed the functional significance of an SRNS-associated gene in vitro and in podocyte-like Drosophila nephrocytes ..."
Monday, November 4, 2019
Experiments in Drosophila contribute to study of human gene variants associated with an early onset epileptic encephalopathy
Suzuki H, Yoshida T, Morisada N, Uehara T, Kosaki K, Sato K, Matsubara K, Takano-Shimizu T, Takenouchi T. De novo NSF mutations cause early infantile epileptic encephalopathy. Ann Clin Transl Neurol. 2019 Nov 1. doi: 10.1002/acn3.50917. PubMed PMID: 31675180.
Abstract: "N-ethylmaleimide-sensitive factor (NSF) plays a critical role in intracellular vesicle transport, which is essential for neurotransmitter release. Herein, we, for the first time, document human monogenic disease phenotype of de novo pathogenic variants in NSF, that is, epileptic encephalopathy of early infantile onset. When expressed in the developing eye of Drosophila, the mutant NSF severely affected eye development, while the wild-type allele had no detectable effect under the same conditions. Our findings suggest that the two pathogenic variants exert a dominant negative effect. De novo heterozygous mutations in the NSF gene cause early infantile epileptic encephalopathy."
Abstract: "N-ethylmaleimide-sensitive factor (NSF) plays a critical role in intracellular vesicle transport, which is essential for neurotransmitter release. Herein, we, for the first time, document human monogenic disease phenotype of de novo pathogenic variants in NSF, that is, epileptic encephalopathy of early infantile onset. When expressed in the developing eye of Drosophila, the mutant NSF severely affected eye development, while the wild-type allele had no detectable effect under the same conditions. Our findings suggest that the two pathogenic variants exert a dominant negative effect. De novo heterozygous mutations in the NSF gene cause early infantile epileptic encephalopathy."
Wednesday, October 30, 2019
Fly study related to distal hereditary motor neuropathy
Kang KH, Han JE, Hong YB, Nam SH, Choi BO, Koh H. Human HSPB1 mutation recapitulates features of distal hereditary motor neuropathy (dHMN) in Drosophila. Biochem Biophys Res Commun. 2019 Oct 17. pii: S0006-291X(19)32012-1. PubMed PMID: 31630804.
Abstract: "Distal hereditary motor neuropathies (dHMN) are a group of inherited peripheral nerve disorders characterized by length-dependent motor neuron weakness and subsequent muscle atrophy. Missense mutations in the gene encoding small heat shock protein HSPB1 (HSP27) have been associated with hereditary neuropathies including dHMN. HSPB1 is a member of the small heat shock protein (sHSP) family characterized by a highly conserved α-crystallin domain that is critical to their chaperone activity. In this study, we modeled HSPB1 mutant-induced neuropathies in Drosophila using a human HSPB1S135F mutant that has a missense mutation in its α-crystallin domain. Overexpression of the HSPB1 mutant produced no significant defect in the Drosophila development, however, a partial reduction in the life span was observed. Further, the HSPB1 mutant gene induced an obvious loss of motor activity when expressed in Drosophila neurons. Moreover, suppression of histone deacetylase 6 (HDAC6) expression, which has critical roles in HSPB1 mutant-induced axonal defects, successfully rescued the motor defects in the HSPB1 mutant Drosophila model."
Abstract: "Distal hereditary motor neuropathies (dHMN) are a group of inherited peripheral nerve disorders characterized by length-dependent motor neuron weakness and subsequent muscle atrophy. Missense mutations in the gene encoding small heat shock protein HSPB1 (HSP27) have been associated with hereditary neuropathies including dHMN. HSPB1 is a member of the small heat shock protein (sHSP) family characterized by a highly conserved α-crystallin domain that is critical to their chaperone activity. In this study, we modeled HSPB1 mutant-induced neuropathies in Drosophila using a human HSPB1S135F mutant that has a missense mutation in its α-crystallin domain. Overexpression of the HSPB1 mutant produced no significant defect in the Drosophila development, however, a partial reduction in the life span was observed. Further, the HSPB1 mutant gene induced an obvious loss of motor activity when expressed in Drosophila neurons. Moreover, suppression of histone deacetylase 6 (HDAC6) expression, which has critical roles in HSPB1 mutant-induced axonal defects, successfully rescued the motor defects in the HSPB1 mutant Drosophila model."
Friday, October 11, 2019
Drosophila studies help identify and understand role of the CSDE1 gene in an autism-related syndrome
Guo H, Li Y, Shen L, Wang T, Jia X, Liu L, Xu T, Ou M, Hoekzema K, Wu H, et al. Disruptive variants of CSDE1 associate with autism and interfere with neuronal development and synaptic transmission. Sci Adv. 2019 Sep 25;5(9):eaax2166. PubMed PMID: 31579823; PubMed Central PMCID: PMC6760934.
Abstract: "RNA binding proteins are key players in posttranscriptional regulation and have been implicated in neurodevelopmental and neuropsychiatric disorders. Here, we report a significant burden of heterozygous, likely gene-disrupting variants in CSDE1 (encoding a highly constrained RNA binding protein) among patients with autism and related neurodevelopmental disabilities. Analysis of 17 patients identifies common phenotypes including autism, intellectual disability, language and motor delay, seizures, macrocephaly, and variable ocular abnormalities. HITS-CLIP revealed that Csde1-binding targets are enriched in autism-associated gene sets, especially FMRP targets, and in neuronal development and synaptic plasticity-related pathways. Csde1 knockdown in primary mouse cortical neurons leads to an overgrowth of the neurites and abnormal dendritic spine morphology/synapse formation and impaired synaptic transmission, whereas mutant and knockdown experiments in Drosophila result in defects in synapse growth and synaptic transmission. Our study defines a new autism-related syndrome and highlights the functional role of CSDE1 in synapse development and synaptic transmission."
Abstract: "RNA binding proteins are key players in posttranscriptional regulation and have been implicated in neurodevelopmental and neuropsychiatric disorders. Here, we report a significant burden of heterozygous, likely gene-disrupting variants in CSDE1 (encoding a highly constrained RNA binding protein) among patients with autism and related neurodevelopmental disabilities. Analysis of 17 patients identifies common phenotypes including autism, intellectual disability, language and motor delay, seizures, macrocephaly, and variable ocular abnormalities. HITS-CLIP revealed that Csde1-binding targets are enriched in autism-associated gene sets, especially FMRP targets, and in neuronal development and synaptic plasticity-related pathways. Csde1 knockdown in primary mouse cortical neurons leads to an overgrowth of the neurites and abnormal dendritic spine morphology/synapse formation and impaired synaptic transmission, whereas mutant and knockdown experiments in Drosophila result in defects in synapse growth and synaptic transmission. Our study defines a new autism-related syndrome and highlights the functional role of CSDE1 in synapse development and synaptic transmission."
Monday, October 7, 2019
New drug target for renal cancer identified based on fly and human studies--work from the lab of 2019 Nobel prize winner W. Kaelin
Nicholson HE, Tariq Z, Housden BE, Jennings RB, Stransky LA, Perrimon N, Signoretti S, Kaelin WG Jr. HIF-independent synthetic lethality between CDK4/6 inhibition and VHL loss across species. Sci Signal. 2019 Oct 1;12(601). PubMed PMID: 31575731.
Abstract: "Inactivation of the VHL tumor suppressor gene is the signature initiating event in clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer, and causes the accumulation of hypoxia-inducible factor 2α (HIF-2α). HIF-2α inhibitors are effective in some ccRCC cases, but both de novo and acquired resistance have been observed in the laboratory and in the clinic. Here, we identified synthetic lethality between decreased activity of cyclin-dependent kinases 4 and 6 (CDK4/6) and VHL inactivation in two species (human and Drosophila) and across diverse human ccRCC cell lines in culture and xenografts. Although HIF-2α transcriptionally induced the CDK4/6 partner cyclin D1, HIF-2α was not required for the increased CDK4/6 requirement of VHL-/- ccRCC cells. Accordingly, the antiproliferative effects of CDK4/6 inhibition were synergistic with HIF-2α inhibition in HIF-2α-dependent VHL-/- ccRCC cells and not antagonistic with HIF-2α inhibition in HIF-2α-independent cells. These findings support testing CDK4/6 inhibitors as treatments for ccRCC, alone and in combination with HIF-2α inhibitors."
Abstract: "Inactivation of the VHL tumor suppressor gene is the signature initiating event in clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer, and causes the accumulation of hypoxia-inducible factor 2α (HIF-2α). HIF-2α inhibitors are effective in some ccRCC cases, but both de novo and acquired resistance have been observed in the laboratory and in the clinic. Here, we identified synthetic lethality between decreased activity of cyclin-dependent kinases 4 and 6 (CDK4/6) and VHL inactivation in two species (human and Drosophila) and across diverse human ccRCC cell lines in culture and xenografts. Although HIF-2α transcriptionally induced the CDK4/6 partner cyclin D1, HIF-2α was not required for the increased CDK4/6 requirement of VHL-/- ccRCC cells. Accordingly, the antiproliferative effects of CDK4/6 inhibition were synergistic with HIF-2α inhibition in HIF-2α-dependent VHL-/- ccRCC cells and not antagonistic with HIF-2α inhibition in HIF-2α-independent cells. These findings support testing CDK4/6 inhibitors as treatments for ccRCC, alone and in combination with HIF-2α inhibitors."
Review: "Insights from Drosophila melanogaster model of Alzheimer's disease"
Tue NT, Dat TQ, Ly LL, Anh VD, Yoshida H. Insights from Drosophila melanogaster model of Alzheimer's disease. Front Biosci (Landmark Ed). 2020 Jan 1;25:134-146. PubMed PMID: 31585881.
Abstract: "Alzheimer's disease (AD) is a common chronic neurodegenerative disease that mainly affects the medial temporal lobe and associated neocortical structures. The disease process involves two abnormal structures, plaques and tangles, which damage and destroy nerve cells. Tangles are twisted fibers of tau protein that build up inside cells. Plaques are deposits of a protein fragment called amyloid-beta (Aβ) that accumulate in the spaces between nerve cells. Aβ derives from the amyloid precursor protein and is the main component of amyloid plaques in the AD brain. Although AD has been extensively examined, its pathogenetic mechanisms remain unclear and there are currently no effective drugs for this disorder. Many AD model systems have recently been established using Drosophila melanogaster by expressing the proteins involved in AD in the brain. These systems successfully reflect some of the symptoms associated with AD such as the onset of learning defects, age-dependent short-term memory impairment, increase of wakefulness and consolidated sleep disruption by expressing human Aβ42 or human APP/BACE in Drosophila central nervous system. We herein discuss these Drosophila AD models."
Abstract: "Alzheimer's disease (AD) is a common chronic neurodegenerative disease that mainly affects the medial temporal lobe and associated neocortical structures. The disease process involves two abnormal structures, plaques and tangles, which damage and destroy nerve cells. Tangles are twisted fibers of tau protein that build up inside cells. Plaques are deposits of a protein fragment called amyloid-beta (Aβ) that accumulate in the spaces between nerve cells. Aβ derives from the amyloid precursor protein and is the main component of amyloid plaques in the AD brain. Although AD has been extensively examined, its pathogenetic mechanisms remain unclear and there are currently no effective drugs for this disorder. Many AD model systems have recently been established using Drosophila melanogaster by expressing the proteins involved in AD in the brain. These systems successfully reflect some of the symptoms associated with AD such as the onset of learning defects, age-dependent short-term memory impairment, increase of wakefulness and consolidated sleep disruption by expressing human Aβ42 or human APP/BACE in Drosophila central nervous system. We herein discuss these Drosophila AD models."
Tuesday, October 1, 2019
Study related to kidney disease uses flies as in vivo test model for follow-up of genes identified in a human cell-based screen
Cina DP, Ketela T, Brown KR, Chandrashekhar M, Mero P, Li C, Onay T, Fu Y, Han Z, Saleem MA, Moffat J, Quaggin SE. Forward genetic screen in human podocytes identifies diphthamide biosynthesis genes as regulators of adhesion. Am J Physiol Renal Physiol. 2019 Sep 30. doi: 10.1152/ajprenal.00195.2019. PubMed PMID: 31566424.
From the abstract: "... To identify novel genes that are important for podocyte function, we designed an in vitro genetic screen based on podocyte adhesion to plates coated with either fibronectin or soluble FLT1/Fc. .. A genome-scale pooled RNA interference screen on immortalized human podocytes identified 77 genes that increased adhesion to fibronectin, 101 genes that increased adhesion to sFLT1/Fc, and 44 genes that increased adhesion to both substrates when knocked down. Multiple shRNAs against each of DPH1, DPH2, DPH3, and DPH4 were top hits ... We then used CRISPR-Cas9 to generate podocyte knockout cells for DPH1, DPH2, or DPH3 which also displayed increased adhesion ... as well as a spreading defect. Last, we showed that Drosophila nephrocyte-specific knock-down of Dph1, Dph2, and Dph4 results in altered nephrocyte function. ... Given the central role of podocyte adhesion as a marker of podocyte health, these data are a rich source of candidate regulators of glomerular disease."
From the abstract: "... To identify novel genes that are important for podocyte function, we designed an in vitro genetic screen based on podocyte adhesion to plates coated with either fibronectin or soluble FLT1/Fc. .. A genome-scale pooled RNA interference screen on immortalized human podocytes identified 77 genes that increased adhesion to fibronectin, 101 genes that increased adhesion to sFLT1/Fc, and 44 genes that increased adhesion to both substrates when knocked down. Multiple shRNAs against each of DPH1, DPH2, DPH3, and DPH4 were top hits ... We then used CRISPR-Cas9 to generate podocyte knockout cells for DPH1, DPH2, or DPH3 which also displayed increased adhesion ... as well as a spreading defect. Last, we showed that Drosophila nephrocyte-specific knock-down of Dph1, Dph2, and Dph4 results in altered nephrocyte function. ... Given the central role of podocyte adhesion as a marker of podocyte health, these data are a rich source of candidate regulators of glomerular disease."
'Multilayered' approach to study of Huntington Disease includes testing in fly HD models
Al-Ramahi I, Lu B, Di Paola S, Pang K, de Haro M, Peluso I, Gallego-Flores T, Malik NT, Erikson K, Bleiberg BA, Avalos M, Fan G, Rivers LE, Laitman AM, Diaz-García JR, Hild M, Palacino J, Liu Z, Medina DL, Botas J. High-Throughput Functional Analysis Distinguishes Pathogenic, Nonpathogenic, and Compensatory Transcriptional Changes in Neurodegeneration. Cell Syst. 2018 Jul 25;7(1):28-40.e4. PubMed PMID: 29936182; PubMed Central PMCID: PMC6082401.
Abstract: "Discriminating transcriptional changes that drive disease pathogenesis from nonpathogenic and compensatory responses is a daunting challenge. This is particularly true for neurodegenerative diseases, which affect the expression of thousands of genes in different brain regions at different disease stages. Here we integrate functional testing and network approaches to analyze previously reported transcriptional alterations in the brains of Huntington disease (HD) patients. We selected 312 genes whose expression is dysregulated both in HD patients and in HD mice and then replicated and/or antagonized each alteration in a Drosophila HD model. High-throughput behavioral testing in this model and controls revealed that transcriptional changes in synaptic biology and calcium signaling are compensatory, whereas alterations involving the actin cytoskeleton and inflammation drive disease. Knockdown of disease-driving genes in HD patient-derived cells lowered mutant Huntingtin levels and activated macroautophagy, suggesting a mechanism for mitigating pathogenesis. Our multilayered approach can thus untangle the wealth of information generated by transcriptomics and identify early therapeutic intervention points."
Abstract: "Discriminating transcriptional changes that drive disease pathogenesis from nonpathogenic and compensatory responses is a daunting challenge. This is particularly true for neurodegenerative diseases, which affect the expression of thousands of genes in different brain regions at different disease stages. Here we integrate functional testing and network approaches to analyze previously reported transcriptional alterations in the brains of Huntington disease (HD) patients. We selected 312 genes whose expression is dysregulated both in HD patients and in HD mice and then replicated and/or antagonized each alteration in a Drosophila HD model. High-throughput behavioral testing in this model and controls revealed that transcriptional changes in synaptic biology and calcium signaling are compensatory, whereas alterations involving the actin cytoskeleton and inflammation drive disease. Knockdown of disease-driving genes in HD patient-derived cells lowered mutant Huntingtin levels and activated macroautophagy, suggesting a mechanism for mitigating pathogenesis. Our multilayered approach can thus untangle the wealth of information generated by transcriptomics and identify early therapeutic intervention points."
Monday, September 30, 2019
Fly model with high uric acid levels established for study of this key risk factor for multiple diseases
Lang S, Hilsabeck TA, Wilson KA, Sharma A, Bose N, Brackman DJ, Beck JN, Chen L, Watson MA, Killilea DW, Ho S, Kahn A, Giacomini K, Stoller ML, Chi T, Kapahi P. A conserved role of the insulin-like signaling pathway in diet-dependent uric acid pathologies in Drosophila melanogaster. PLoS Genet. 2019 Aug 15;15(8):e1008318. PubMed PMID: 31415568; PubMed Central PMCID: PMC6695094.
From the abstract: "Elevated uric acid (UA) is a key risk factor for many disorders, including metabolic syndrome, gout and kidney stones. ... In humans, elevated UA levels resulted from the loss of the of the urate oxidase (Uro) gene ... we established a Drosophila melanogaster model with reduced expression of the orthologous Uro gene to study the pathogenesis arising from elevated UA. Reduced Uro expression in Drosophila resulted in elevated UA levels, accumulation of concretions in the excretory system, and shortening of lifespan ..."
From the abstract: "Elevated uric acid (UA) is a key risk factor for many disorders, including metabolic syndrome, gout and kidney stones. ... In humans, elevated UA levels resulted from the loss of the of the urate oxidase (Uro) gene ... we established a Drosophila melanogaster model with reduced expression of the orthologous Uro gene to study the pathogenesis arising from elevated UA. Reduced Uro expression in Drosophila resulted in elevated UA levels, accumulation of concretions in the excretory system, and shortening of lifespan ..."
Drosophila as model for studying genotype influence on response to high sugar consumption
Branch A, Zhang Y, Shen P. Genetic and Neurobiological Analyses of the Noradrenergic-like System in Vulnerability to Sugar Overconsumption Using a Drosophila Model. Sci Rep. 2017 Dec 15;7(1):17642. PubMed PMID: 29247240; PubMed Central PMCID: PMC5732301.
From the abstract: "Regular overconsumption of sugar is associated with obesity and type-2 diabetes, but how genetic factors contribute to variable sugar preferences and intake levels remains mostly unclear. Here we provide evidence for the usefulness of a Drosophila larva model to investigate genetic influence on vulnerability to sugar overconsumption. ..."
From the abstract: "Regular overconsumption of sugar is associated with obesity and type-2 diabetes, but how genetic factors contribute to variable sugar preferences and intake levels remains mostly unclear. Here we provide evidence for the usefulness of a Drosophila larva model to investigate genetic influence on vulnerability to sugar overconsumption. ..."
Methods report -- Drosophila and the study of Fragile X Syndrome
Kong HE, Lim J, Jin P. Application of Drosophila Model Toward Understanding the Molecular Basis of Fragile X Syndrome. Methods Mol Biol. 2019;1942:141-153. PubMed PMID: 30900182.
Flies used in international effort to identify mutations associated with a recessive form of ataxia or spastic paraplegia
Seong E, Insolera R, Dulovic M, Kamsteeg EJ, Trinh J, Brüggemann N, Sandford E, Li S, Ozel AB, Li JZ, Jewett T, Kievit AJA, Münchau A, Shakkottai V, Klein C, Collins CA, Lohmann K, van de Warrenburg BP, Burmeister M. Mutations in VPS13D lead to a new recessive ataxia with spasticity and mitochondrial defects. Ann Neurol. 2018 Jun;83(6):1075-1088. PubMed PMID: 29604224; PubMed Central PMCID: PMC6105379.
From the abstract: "To identify novel causes of recessive ataxias, including spinocerebellar ataxia with saccadic intrusions, spastic ataxias, and spastic paraplegia. ... In an international collaboration, we independently performed exome sequencing in 7 families with recessive ataxia and/or spastic paraplegia. To evaluate the role of VPS13D mutations, we evaluated a Drosophila knockout model and investigated mitochondrial function in patient-derived fibroblast cultures. ... Our study demonstrates that compound heterozygous mutations in VPS13D cause movement disorders along the ataxia-spasticity spectrum, making VPS13D the fourth VPS13 paralog involved in neurological disorders."
See also:
Fogel BL. Collaborative science unites researchers and a novel spastic ataxia gene. Ann Neurol. 2018 Jun;83(6):1072-1074. PubMed PMID: 29908061; PubMed Central PMCID: PMC6105536.
From the abstract: "To identify novel causes of recessive ataxias, including spinocerebellar ataxia with saccadic intrusions, spastic ataxias, and spastic paraplegia. ... In an international collaboration, we independently performed exome sequencing in 7 families with recessive ataxia and/or spastic paraplegia. To evaluate the role of VPS13D mutations, we evaluated a Drosophila knockout model and investigated mitochondrial function in patient-derived fibroblast cultures. ... Our study demonstrates that compound heterozygous mutations in VPS13D cause movement disorders along the ataxia-spasticity spectrum, making VPS13D the fourth VPS13 paralog involved in neurological disorders."
See also:
Fogel BL. Collaborative science unites researchers and a novel spastic ataxia gene. Ann Neurol. 2018 Jun;83(6):1072-1074. PubMed PMID: 29908061; PubMed Central PMCID: PMC6105536.
Several new studies and a review related to Alzheimer's disease and other neurodegenerative and age-related disorders
Goldberg J, Currais A, Prior M, Fischer W, Chiruta C, Ratliff E, Daugherty D, Dargusch R, Finley K, Esparza-Moltó PB, Cuezva JM, Maher P, Petrascheck M, Schubert D. The mitochondrial ATP synthase is a shared drug target for aging and dementia. Aging Cell. 2018 Apr;17(2). PubMed PMID: 29316249; PubMed Central PMCID: PMC5847861.
Ojelade SA, Lee TV, Giagtzoglou N, Yu L, Ugur B, Li Y, Duraine L, Zuo Z, Petyuk V, De Jager PL, Bennett DA, Arenkiel BR, Bellen HJ, Shulman JM. cindr, the Drosophila Homolog of the CD2AP Alzheimer's Disease Risk Gene, Is Required for Synaptic Transmission and Proteostasis. Cell Rep. 2019 Aug 13;28(7):1799-1813.e5. PubMed PMID: 31412248; PubMed Central PMCID:
PMC6703184.
Yang L, Cao Y, Zhao J, Fang Y, Liu N, Zhang Y. Multidimensional proteomics identifies declines in protein homeostasis and mitochondria as early signals for normal aging and age-associated disease in Drosophila. Mol Cell Proteomics. 2019 Aug 21. pii: mcp.RA119.001621. PubMed PMID: 31434710.
Park SY, Seo J, Chun YS. Targeted Downregulation of kdm4a Ameliorates Tau-engendered Defects in Drosophila melanogaster. J Korean Med Sci. 2019 Aug 26;34(33):e225. doi: 10.3346/jkms.2019.34.e225. PubMed PMID: 31436053; PubMed Central PMCID: PMC6706347.
Sun M, Zhao Y, Han M, Zhang B, Zhang X, Zhang Q, Lim NK, Wang WA, Huang FD. TTC7 and Hyccin Regulate Neuronal Aβ42 Accumulation and its Associated Neural Deficits in Aβ42-Expressing Drosophila. J Alzheimers Dis. 2018;65(3):1001-1010. PubMed PMID: 30103315.
Passarella D, Goedert M. Beta-sheet assembly of Tau and neurodegeneration in Drosophila melanogaster. Neurobiol Aging. 2018 Dec;72:98-105. PubMed PMID: 30240946;
PubMed Central PMCID: PMC6327151.
Gusareva ES, Twizere JC, Sleegers K, Dourlen P, Abisambra JF, Meier S, Cloyd R, Weiss B, Dermaut B, Bessonov K, et al. Male-specific epistasis between WWC1 and TLN2 genes is associated with Alzheimer's disease. Neurobiol Aging. 2018 Dec;72:188.e3-188.e12. PubMed PMID: 30201328.
Jantrapirom S, Lo Piccolo L, Yamaguchi M. Non-Proteasomal UbL-UbA Family of Proteins in Neurodegeneration. Int J Mol Sci. 2019 Apr 17;20(8). pii: E1893. Review. PubMed PMID: 30999567; PubMed Central PMCID: PMC6514573.
Bajracharya R, Youngson NA, Ballard JWO. Dietary Macronutrient Management to Treat Mitochondrial Dysfunction in Parkinson's Disease. Int J Mol Sci. 2019 Apr 15;20(8). pii: E1850. doi: 10.3390/ijms20081850. Review. PubMed PMID: 30991634; PubMed Central PMCID: PMC6514887.
Ojelade SA, Lee TV, Giagtzoglou N, Yu L, Ugur B, Li Y, Duraine L, Zuo Z, Petyuk V, De Jager PL, Bennett DA, Arenkiel BR, Bellen HJ, Shulman JM. cindr, the Drosophila Homolog of the CD2AP Alzheimer's Disease Risk Gene, Is Required for Synaptic Transmission and Proteostasis. Cell Rep. 2019 Aug 13;28(7):1799-1813.e5. PubMed PMID: 31412248; PubMed Central PMCID:
PMC6703184.
Yang L, Cao Y, Zhao J, Fang Y, Liu N, Zhang Y. Multidimensional proteomics identifies declines in protein homeostasis and mitochondria as early signals for normal aging and age-associated disease in Drosophila. Mol Cell Proteomics. 2019 Aug 21. pii: mcp.RA119.001621. PubMed PMID: 31434710.
Park SY, Seo J, Chun YS. Targeted Downregulation of kdm4a Ameliorates Tau-engendered Defects in Drosophila melanogaster. J Korean Med Sci. 2019 Aug 26;34(33):e225. doi: 10.3346/jkms.2019.34.e225. PubMed PMID: 31436053; PubMed Central PMCID: PMC6706347.
Sun M, Zhao Y, Han M, Zhang B, Zhang X, Zhang Q, Lim NK, Wang WA, Huang FD. TTC7 and Hyccin Regulate Neuronal Aβ42 Accumulation and its Associated Neural Deficits in Aβ42-Expressing Drosophila. J Alzheimers Dis. 2018;65(3):1001-1010. PubMed PMID: 30103315.
Passarella D, Goedert M. Beta-sheet assembly of Tau and neurodegeneration in Drosophila melanogaster. Neurobiol Aging. 2018 Dec;72:98-105. PubMed PMID: 30240946;
PubMed Central PMCID: PMC6327151.
Gusareva ES, Twizere JC, Sleegers K, Dourlen P, Abisambra JF, Meier S, Cloyd R, Weiss B, Dermaut B, Bessonov K, et al. Male-specific epistasis between WWC1 and TLN2 genes is associated with Alzheimer's disease. Neurobiol Aging. 2018 Dec;72:188.e3-188.e12. PubMed PMID: 30201328.
Jantrapirom S, Lo Piccolo L, Yamaguchi M. Non-Proteasomal UbL-UbA Family of Proteins in Neurodegeneration. Int J Mol Sci. 2019 Apr 17;20(8). pii: E1893. Review. PubMed PMID: 30999567; PubMed Central PMCID: PMC6514573.
Bajracharya R, Youngson NA, Ballard JWO. Dietary Macronutrient Management to Treat Mitochondrial Dysfunction in Parkinson's Disease. Int J Mol Sci. 2019 Apr 15;20(8). pii: E1850. doi: 10.3390/ijms20081850. Review. PubMed PMID: 30991634; PubMed Central PMCID: PMC6514887.
Drosophila used in study of receptor for entry into cells of disease-causing viruses
Zhang R, Earnest JT, Kim AS, Winkler ES, Desai P, Adams LJ, Hu G, Bullock C, Gold B, Cherry S, Diamond MS. Expression of the Mxra8 Receptor Promotes Alphavirus Infection and Pathogenesis in Mice and Drosophila. Cell Rep. 2019 Sep 3;28(10):2647-2658.e5. doi: 10.1016/j.celrep.2019.07.105. PubMed PMID: 31484075; PubMed Central PMCID: PMC6745702.
From the abstract: "Mxra8 is a recently described receptor for multiple alphaviruses, including Chikungunya (CHIKV), Mayaro (MAYV), Ross River (RRV), and O'nyong nyong (ONNV) viruses. ... Ectopic Mxra8 expression is sufficient to enhance CHIKV infection and lethality in transgenic flies. ... targeting this protein may mitigate disease in humans."
From the abstract: "Mxra8 is a recently described receptor for multiple alphaviruses, including Chikungunya (CHIKV), Mayaro (MAYV), Ross River (RRV), and O'nyong nyong (ONNV) viruses. ... Ectopic Mxra8 expression is sufficient to enhance CHIKV infection and lethality in transgenic flies. ... targeting this protein may mitigate disease in humans."
Drosophila protein crystal structure proves useful in study of PURA syndrome
Reijnders MRF, Janowski R, Alvi M, Self JE, van Essen TJ, Vreeburg M, Rouhl RPW, Stevens SJC, Stegmann APA, Schieving J, et al. PURA syndrome: clinical delineation and genotype-phenotype study in 32 individuals with review of published literature. J Med Genet. 2018 Feb;55(2):104-113. PubMed PMID: 29097605; PubMed Central PMCID: PMC5800346.
From the abstract: "De novo mutations in PURA have recently been described to cause PURA syndrome, a neurodevelopmental disorder characterised by severe intellectual disability (ID), epilepsy, feeding difficulties and neonatal hypotonia. ... We systematically collected clinical and mutation data on newly ascertained PURA syndrome individuals, evaluated data of previously reported individuals and performed a computational analysis of photographs. We classified mutations based on predicted effect using 3D in silico models of crystal structures of Drosophila-derived Pur-alpha homologues. ... "
From the abstract: "De novo mutations in PURA have recently been described to cause PURA syndrome, a neurodevelopmental disorder characterised by severe intellectual disability (ID), epilepsy, feeding difficulties and neonatal hypotonia. ... We systematically collected clinical and mutation data on newly ascertained PURA syndrome individuals, evaluated data of previously reported individuals and performed a computational analysis of photographs. We classified mutations based on predicted effect using 3D in silico models of crystal structures of Drosophila-derived Pur-alpha homologues. ... "
Review highlights Drosophila research contribution to understanding mTOR and tuberous sclerosis
Franz DN, Krueger DA. mTOR inhibitor therapy as a disease modifying therapy for tuberous sclerosis complex. Am J Med Genet C Semin Med Genet. 2018 Sep;178(3):365-373. doi: 10.1002/ajmg.c.31655. Review. PubMed PMID: 30307123.
Abstract: "Between 1993 and 2003, through experiments involving Drosophila sp., cancer biologists identified the protein kinase known as the mammalian target of rapamycin, its pathway, and its relationship to the genes responsible for tuberous sclerosis. Thereafter, clinical research has resulted in regulatory approval of mTOR inhibitors for four distinct manifestations of the disease: giant cell astrocytoma, angiomyolipoma, lymphangioleiomyomatosis, and epilepsy. These developments are summarized and the practical use of mTOR inhibitors to improve the lives of patients with tuberous sclerosis reviewed."
Abstract: "Between 1993 and 2003, through experiments involving Drosophila sp., cancer biologists identified the protein kinase known as the mammalian target of rapamycin, its pathway, and its relationship to the genes responsible for tuberous sclerosis. Thereafter, clinical research has resulted in regulatory approval of mTOR inhibitors for four distinct manifestations of the disease: giant cell astrocytoma, angiomyolipoma, lymphangioleiomyomatosis, and epilepsy. These developments are summarized and the practical use of mTOR inhibitors to improve the lives of patients with tuberous sclerosis reviewed."
Fly model of Alzheimers disease used in study of potential therapeutic treatment
Viswanathan GK, Shwartz D, Losev Y, Arad E, Shemesh C, Pichinuk E, Engel H, Raveh A, Jelinek R, Cooper I, Gosselet F, Gazit E, Segal D. Purpurin modulates Tau-derived VQIVYK fibrillization and ameliorates Alzheimer's disease-like symptoms in animal model. Cell Mol Life Sci. 2019 Sep 27. PubMed PMID: 31562564.
Abstract: "Neurofibrillary tangles of the Tau protein and plaques of the amyloid β peptide are hallmarks of Alzheimer's disease (AD), which is characterized by the conversion of monomeric proteins/peptides into misfolded β-sheet rich fibrils. Halting the fibrillation process and disrupting the existing aggregates are key challenges for AD drug development. Previously, we performed in vitro high-throughput screening for the identification of potent inhibitors of Tau aggregation using a proxy model, a highly aggregation-prone hexapeptide fragment 306VQIVYK311 (termed PHF6) derived from Tau. Here we have characterized a hit molecule from that screen as a modulator of Tau aggregation using in vitro, in silico, and in vivo techniques. This molecule, an anthraquinone derivative named Purpurin, inhibited ~ 50% of PHF6 fibrillization in vitro at equimolar concentration and disassembled pre-formed PHF6 fibrils. In silico studies showed that Purpurin interacted with key residues of PHF6, which are responsible for maintaining its β-sheets conformation. Isothermal titration calorimetry and surface plasmon resonance experiments with PHF6 and full-length Tau (FL-Tau), respectively, indicated that Purpurin interacted with PHF6 predominantly via hydrophobic contacts and displayed a dose-dependent complexation with FL-Tau. Purpurin was non-toxic when fed to Drosophila and it significantly ameliorated the AD-related neurotoxic symptoms of transgenic flies expressing WT-FL human Tau (hTau) plausibly by inhibiting Tau accumulation and reducing Tau phosphorylation. Purpurin also reduced hTau accumulation in cell culture overexpressing hTau. Importantly, Purpurin efficiently crossed an in vitro human blood-brain barrier model. Our findings suggest that Purpurin could be a potential lead molecule for AD therapeutics."
Abstract: "Neurofibrillary tangles of the Tau protein and plaques of the amyloid β peptide are hallmarks of Alzheimer's disease (AD), which is characterized by the conversion of monomeric proteins/peptides into misfolded β-sheet rich fibrils. Halting the fibrillation process and disrupting the existing aggregates are key challenges for AD drug development. Previously, we performed in vitro high-throughput screening for the identification of potent inhibitors of Tau aggregation using a proxy model, a highly aggregation-prone hexapeptide fragment 306VQIVYK311 (termed PHF6) derived from Tau. Here we have characterized a hit molecule from that screen as a modulator of Tau aggregation using in vitro, in silico, and in vivo techniques. This molecule, an anthraquinone derivative named Purpurin, inhibited ~ 50% of PHF6 fibrillization in vitro at equimolar concentration and disassembled pre-formed PHF6 fibrils. In silico studies showed that Purpurin interacted with key residues of PHF6, which are responsible for maintaining its β-sheets conformation. Isothermal titration calorimetry and surface plasmon resonance experiments with PHF6 and full-length Tau (FL-Tau), respectively, indicated that Purpurin interacted with PHF6 predominantly via hydrophobic contacts and displayed a dose-dependent complexation with FL-Tau. Purpurin was non-toxic when fed to Drosophila and it significantly ameliorated the AD-related neurotoxic symptoms of transgenic flies expressing WT-FL human Tau (hTau) plausibly by inhibiting Tau accumulation and reducing Tau phosphorylation. Purpurin also reduced hTau accumulation in cell culture overexpressing hTau. Importantly, Purpurin efficiently crossed an in vitro human blood-brain barrier model. Our findings suggest that Purpurin could be a potential lead molecule for AD therapeutics."
New fly study relevant to Alzheimers disease
Higham JP, Hidalgo S, Buhl E, Hodge JJL. Restoration of Olfactory Memory in Drosophila Overexpressing Human Alzheimer's Disease Associated Tau by Manipulation of L-Type Ca(2+) Channels. Front Cell Neurosci. 2019 Sep 10;13:409. PubMed PMID: 31551716; PubMed Central PMCID: PMC6746915.
Abstract: "The cellular underpinnings of memory deficits in Alzheimer's disease (AD) are poorly understood. We utilized the tractable neural circuits sub-serving memory in Drosophila to investigate the role of impaired Ca2+ handling in memory deficits caused by expression of human 0N4R isoform of tau which is associated with AD. Expression of tau in mushroom body neuropils, or a subset of mushroom body output neurons, led to impaired memory. By using the Ca2+ reporter GCaMP6f, we observed changes in Ca2+ signaling when tau was expressed in these neurons, an effect that could be blocked by the L-type Ca2+ channel antagonist nimodipine or reversed by RNAi knock-down of the L-type channel gene. The L-type Ca2+ channel itself is required for memory formation, however, RNAi knock-down of the L-type Ca2+ channel in neurons overexpressing human tau resulted in flies whose memory is restored to levels equivalent to wild-type. Expression data suggest that Drosophila L-type Ca2+ channel mRNA levels are increased upon tau expression in neurons, thus contributing to the effects observed on memory and intracellular Ca2+ homeostasis. Together, our Ca2+ imaging and memory experiments suggest that expression of the 0N4R isoform of human tau increases the number of L-type Ca2+ channels in the membrane resulting in changes in neuronal excitability that can be ameliorated by RNAi knockdown or pharmacological blockade of L-type Ca2+ channels. This highlights a role for L-type Ca2+ channels in tauopathy and their potential as a therapeutic target for AD."
Abstract: "The cellular underpinnings of memory deficits in Alzheimer's disease (AD) are poorly understood. We utilized the tractable neural circuits sub-serving memory in Drosophila to investigate the role of impaired Ca2+ handling in memory deficits caused by expression of human 0N4R isoform of tau which is associated with AD. Expression of tau in mushroom body neuropils, or a subset of mushroom body output neurons, led to impaired memory. By using the Ca2+ reporter GCaMP6f, we observed changes in Ca2+ signaling when tau was expressed in these neurons, an effect that could be blocked by the L-type Ca2+ channel antagonist nimodipine or reversed by RNAi knock-down of the L-type channel gene. The L-type Ca2+ channel itself is required for memory formation, however, RNAi knock-down of the L-type Ca2+ channel in neurons overexpressing human tau resulted in flies whose memory is restored to levels equivalent to wild-type. Expression data suggest that Drosophila L-type Ca2+ channel mRNA levels are increased upon tau expression in neurons, thus contributing to the effects observed on memory and intracellular Ca2+ homeostasis. Together, our Ca2+ imaging and memory experiments suggest that expression of the 0N4R isoform of human tau increases the number of L-type Ca2+ channels in the membrane resulting in changes in neuronal excitability that can be ameliorated by RNAi knockdown or pharmacological blockade of L-type Ca2+ channels. This highlights a role for L-type Ca2+ channels in tauopathy and their potential as a therapeutic target for AD."
Monday, September 16, 2019
Fly model of Werner syndrome
Cassidy D, Epiney D, Salameh C, Zhou LT, Salomon RN, Schirmer AE, McVey M, Bolterstein E. Evidence for premature aging in a Drosophila model of Werner syndrome. Exp Gerontol. 2019 Sep 10:110733. doi: 10.1016/j.exger.2019.110733. PMID: 31518666.
Abstract: "Werner syndrome (WS) is an autosomal recessive progeroid disease characterized by patients' early onset of aging, increased risk of cancer and other age-related pathologies. WS is caused by mutations in WRN, a RecQ helicase that has essential roles responding to DNA damage and preventing genomic instability. While human WRN has both an exonuclease and helicase domain, Drosophila WRNexo has high genetic and functional homology to only the exonuclease domain of WRN. Like WRN-deficient human cells, Drosophila WRNexo null mutants (WRNexoΔ) are sensitive to replication stress, demonstrating mechanistic similarities between these two models. Compared to age-matched wild-type controls, WRNexoΔ flies exhibit increased physiological signs of aging, such as shorter lifespans, higher tumor incidence, muscle degeneration, reduced climbing ability, altered behavior, and reduced locomotor activity. Interestingly, these effects are more pronounced in females suggesting sex-specific differences in the role of WRNexo in aging. This and future mechanistic studies will contribute to our knowledge in linking faulty DNA repair mechanisms with the process of aging."
Abstract: "Werner syndrome (WS) is an autosomal recessive progeroid disease characterized by patients' early onset of aging, increased risk of cancer and other age-related pathologies. WS is caused by mutations in WRN, a RecQ helicase that has essential roles responding to DNA damage and preventing genomic instability. While human WRN has both an exonuclease and helicase domain, Drosophila WRNexo has high genetic and functional homology to only the exonuclease domain of WRN. Like WRN-deficient human cells, Drosophila WRNexo null mutants (WRNexoΔ) are sensitive to replication stress, demonstrating mechanistic similarities between these two models. Compared to age-matched wild-type controls, WRNexoΔ flies exhibit increased physiological signs of aging, such as shorter lifespans, higher tumor incidence, muscle degeneration, reduced climbing ability, altered behavior, and reduced locomotor activity. Interestingly, these effects are more pronounced in females suggesting sex-specific differences in the role of WRNexo in aging. This and future mechanistic studies will contribute to our knowledge in linking faulty DNA repair mechanisms with the process of aging."
Video protocols published -- on bioinformatics and experimental approaches to using flies to study human gene variants
Wang J, Liu Z, Bellen HJ, Yamamoto S. Navigating MARRVEL, a Web-Based Tool that Integrates Human Genomics and Model Organism Genetics Information. J Vis Exp. 2019 Aug 15;(150). doi: 10.3791/59542. PubMed PMID: 31475990.
From the abstract: "Through whole-exome/genome sequencing, human geneticists identify rare variants that segregate with disease phenotypes. To assess if a specific variant is pathogenic, one must query many databases ... MARRVEL (Model organism Aggregated Resources for Rare Variant ExpLoration) is a one-stop data collection tool for human genes and variants and their orthologous genes in seven model organisms including in mouse, rat, zebrafish, fruit fly, nematode worm, fission yeast, and budding yeast. In this Protocol, we provide an overview of what MARRVEL can be used for and discuss how different datasets can be used to assess whether a variant of unknown significance (VUS) in a known disease-causing gene or a variant in a gene of uncertain significance (GUS) may be pathogenic. ... MARRVEL is an easily accessible open access website designed for both clinical and basic researchers and serves as a starting point to design experiments for functional studies."
Harnish JM, Deal SL, Chao HT, Wangler MF, Yamamoto S. In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila. J Vis Exp. 2019 Aug 20;(150). doi: 10.3791/59658. PubMed PMID: 31498321.
From the abstract: "... In the Undiagnosed Diseases Network (UDN) and other rare disease research consortia, model organisms (MO) including Drosophila, C. elegans, zebrafish, and mice are actively used to assess the function of putative human disease-causing variants. This protocol describes a method for the functional assessment of rare human variants ... The workflow begins with gathering human and MO information from multiple public databases, using the MARRVEL web resource ... Next, genetic tools ... are generated to assess the functions of variants of interest in Drosophila. ... This protocol allows rapid, in vivo assessments of putative human disease-causing variants of genes with known and unknown functions."
From the abstract: "Through whole-exome/genome sequencing, human geneticists identify rare variants that segregate with disease phenotypes. To assess if a specific variant is pathogenic, one must query many databases ... MARRVEL (Model organism Aggregated Resources for Rare Variant ExpLoration) is a one-stop data collection tool for human genes and variants and their orthologous genes in seven model organisms including in mouse, rat, zebrafish, fruit fly, nematode worm, fission yeast, and budding yeast. In this Protocol, we provide an overview of what MARRVEL can be used for and discuss how different datasets can be used to assess whether a variant of unknown significance (VUS) in a known disease-causing gene or a variant in a gene of uncertain significance (GUS) may be pathogenic. ... MARRVEL is an easily accessible open access website designed for both clinical and basic researchers and serves as a starting point to design experiments for functional studies."
Harnish JM, Deal SL, Chao HT, Wangler MF, Yamamoto S. In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila. J Vis Exp. 2019 Aug 20;(150). doi: 10.3791/59658. PubMed PMID: 31498321.
From the abstract: "... In the Undiagnosed Diseases Network (UDN) and other rare disease research consortia, model organisms (MO) including Drosophila, C. elegans, zebrafish, and mice are actively used to assess the function of putative human disease-causing variants. This protocol describes a method for the functional assessment of rare human variants ... The workflow begins with gathering human and MO information from multiple public databases, using the MARRVEL web resource ... Next, genetic tools ... are generated to assess the functions of variants of interest in Drosophila. ... This protocol allows rapid, in vivo assessments of putative human disease-causing variants of genes with known and unknown functions."
Friday, September 13, 2019
Drosophila used to define a "priority list" of genes associated with albuminuria
Teumer A, et al. Genome-wide association meta-analyses and fine-mapping elucidate pathways influencing albuminuria. Nat Commun. 2019 Sep 11;10(1):4130. PMID: 31511532.
Abstract: "Increased levels of the urinary albumin-to-creatinine ratio (UACR) are associated with higher risk of kidney disease progression and cardiovascular events, but underlying mechanisms are incompletely understood. Here, we conduct trans-ethnic (n = 564,257) and European-ancestry specific meta-analyses of genome-wide association studies of UACR, including ancestry- and diabetes-specific analyses, and identify 68 UACR-associated loci. Genetic correlation analyses and risk score associations in an independent electronic medical records database (n = 192,868) reveal connections with proteinuria, hyperlipidemia, gout, and hypertension. Fine-mapping and trans-Omics analyses with gene expression in 47 tissues and plasma protein levels implicate genes potentially operating through differential expression in kidney (including TGFB1, MUC1, PRKCI, and OAF), and allow coupling of UACR associations to altered plasma OAF concentrations. Knockdown of OAF and PRKCI orthologs in Drosophila nephrocytes reduces albumin endocytosis. Silencing fly PRKCI further impairs slit diaphragm formation. These results generate a priority list of genes and pathways for translational research to reduce albuminuria."
Abstract: "Increased levels of the urinary albumin-to-creatinine ratio (UACR) are associated with higher risk of kidney disease progression and cardiovascular events, but underlying mechanisms are incompletely understood. Here, we conduct trans-ethnic (n = 564,257) and European-ancestry specific meta-analyses of genome-wide association studies of UACR, including ancestry- and diabetes-specific analyses, and identify 68 UACR-associated loci. Genetic correlation analyses and risk score associations in an independent electronic medical records database (n = 192,868) reveal connections with proteinuria, hyperlipidemia, gout, and hypertension. Fine-mapping and trans-Omics analyses with gene expression in 47 tissues and plasma protein levels implicate genes potentially operating through differential expression in kidney (including TGFB1, MUC1, PRKCI, and OAF), and allow coupling of UACR associations to altered plasma OAF concentrations. Knockdown of OAF and PRKCI orthologs in Drosophila nephrocytes reduces albumin endocytosis. Silencing fly PRKCI further impairs slit diaphragm formation. These results generate a priority list of genes and pathways for translational research to reduce albuminuria."
Thursday, September 5, 2019
Advanced Review on the use of Drosophila in drug screening
Su TT. Drug screening in Drosophila; why, when, and when not? Wiley Interdiscip Rev Dev Biol. 2019 May 5:e346. doi: 10.1002/wdev.346. PubMed PMID: 31056843.
Abstract: "The best global seller among oncology drugs in 2018 is lenalidomide, an analog of thalidomide. It took 53 years and a circuitous route from the discovery of thalidomide to approval of an analog for use in treatment of cancer. We understand now a lot more about the genetic and molecular basis of diseases than we did in 1953 when thalidomide was discovered. We have also no shortage of chemical libraries with hundreds of thousands of compounds, both synthetic and natural. What we need are better ways to search among these rich resources for compounds with the potential to do what we want them to do. This review summarizes examples from the literature that make Drosophila melanogaster a good model to screen for drugs, and discusses knowledge gaps and technical challenges that make Drosophila models not as widely used as they could or should be."
Abstract: "The best global seller among oncology drugs in 2018 is lenalidomide, an analog of thalidomide. It took 53 years and a circuitous route from the discovery of thalidomide to approval of an analog for use in treatment of cancer. We understand now a lot more about the genetic and molecular basis of diseases than we did in 1953 when thalidomide was discovered. We have also no shortage of chemical libraries with hundreds of thousands of compounds, both synthetic and natural. What we need are better ways to search among these rich resources for compounds with the potential to do what we want them to do. This review summarizes examples from the literature that make Drosophila melanogaster a good model to screen for drugs, and discusses knowledge gaps and technical challenges that make Drosophila models not as widely used as they could or should be."
Wednesday, September 4, 2019
Whole-animal fly system facilitates study relevant to cancer metastasis
Mishra-Gorur K, Li D, Ma X, Yarman Y, Xue L, Xu T. Spz/Toll-6 signal guides organotropic metastasis in Drosophila. Dis Model Mech. 2019 Sep 2. pii: dmm.039727. doi: 10.1242/dmm.039727. PubMed PMID: 31477571.
Abstract: "Targeted cell migration plays important roles in developmental biology and disease processes including metastasis. Drosophila tumors exhibit traits characteristic of human cancers, providing a powerful model to study developmental and cancer biology. We now find that cells derived from Drosophila eye disc tumors also display organ specific metastasis to invade receptive organs but not wing disc. Toll receptors are known to affect innate immunity and tumor inflammatory microenvironment by modulating the NF-κB pathway. Our RNAi screen and genetic analyses show that Toll-6 is required for migration and invasion of the tumor cells. Further, receptive organs express Toll-ligands, Spz family molecules, and ectopic Spz expression renders wing disc receptive to metastasis. Finally, Toll-6 promotes metastasis by activating JNK signaling, a key regulator of cell migration. Hence, we report Toll-6 and Spätzle as a new pair of guidance molecules mediating organ-specific metastasis behavior and highlight a novel signaling mechanism for Toll family receptors."
Abstract: "Targeted cell migration plays important roles in developmental biology and disease processes including metastasis. Drosophila tumors exhibit traits characteristic of human cancers, providing a powerful model to study developmental and cancer biology. We now find that cells derived from Drosophila eye disc tumors also display organ specific metastasis to invade receptive organs but not wing disc. Toll receptors are known to affect innate immunity and tumor inflammatory microenvironment by modulating the NF-κB pathway. Our RNAi screen and genetic analyses show that Toll-6 is required for migration and invasion of the tumor cells. Further, receptive organs express Toll-ligands, Spz family molecules, and ectopic Spz expression renders wing disc receptive to metastasis. Finally, Toll-6 promotes metastasis by activating JNK signaling, a key regulator of cell migration. Hence, we report Toll-6 and Spätzle as a new pair of guidance molecules mediating organ-specific metastasis behavior and highlight a novel signaling mechanism for Toll family receptors."
Friday, August 30, 2019
Fly model of glioma used to identify potential therapeutic target
Chi KC, Tsai WC, Wu CL, Lin TY, Hueng DY. An Adult Drosophila Glioma Model for Studying Pathometabolic Pathways of Gliomagenesis. Mol Neurobiol. 2019 Jun;56(6):4589-4599. doi: 10.1007/s12035-018-1392-2. Epub 2018 Oct 24. PubMed PMID: 30357574.
Abstract: "Glioblastoma multiforme (GBM), the most prevalent brain tumor in adults, has extremely poor prognosis. Frequent genetic alterations that activate epidermal growth factor receptor (EGFR) and phosphatidylinositol-3 kinase (PI3K) signaling, as well as metabolic remodeling, have been associated with gliomagenesis. To establish a whole-animal approach that can be used to readily identify individual pathometabolic signaling factors, we induced glioma formation in the adult Drosophila brain by activating the EGFR-PI3K pathway. Glioma-induced animals showed significantly enlarged brain volume, early locomotor abnormalities, memory deficits, and a shorter lifespan. Combining bioinformatics analysis and glial-specific gene knockdown in the adult fly glioma model, we identified four evolutionarily conserved metabolic genes, including ALDOA, ACAT1, ELOVL6, and LOX, that were involved in gliomagenesis. Silencing of ACAT1, which controls cholesterol homeostasis, reduced brain enlargement and increased the lifespan of the glioma-bearing flies. In GBM patients, ACAT1 is overexpressed and correlates with poor survival outcomes. Moreover, pharmacological inhibition of ACAT1 in human glioma cell lines revealed that it is essential for tumor proliferation. Collectively, these results imply that ACAT1 is a potential therapeutic target, and cholesterol homeostasis is strongly related to glioma formation. This in vivo model provides several rapid and robust phenotypic readouts, allowing determination of the pathometabolic pathways involved in gliomagenesis, as well as providing valuable information for novel therapeutic strategies."
Abstract: "Glioblastoma multiforme (GBM), the most prevalent brain tumor in adults, has extremely poor prognosis. Frequent genetic alterations that activate epidermal growth factor receptor (EGFR) and phosphatidylinositol-3 kinase (PI3K) signaling, as well as metabolic remodeling, have been associated with gliomagenesis. To establish a whole-animal approach that can be used to readily identify individual pathometabolic signaling factors, we induced glioma formation in the adult Drosophila brain by activating the EGFR-PI3K pathway. Glioma-induced animals showed significantly enlarged brain volume, early locomotor abnormalities, memory deficits, and a shorter lifespan. Combining bioinformatics analysis and glial-specific gene knockdown in the adult fly glioma model, we identified four evolutionarily conserved metabolic genes, including ALDOA, ACAT1, ELOVL6, and LOX, that were involved in gliomagenesis. Silencing of ACAT1, which controls cholesterol homeostasis, reduced brain enlargement and increased the lifespan of the glioma-bearing flies. In GBM patients, ACAT1 is overexpressed and correlates with poor survival outcomes. Moreover, pharmacological inhibition of ACAT1 in human glioma cell lines revealed that it is essential for tumor proliferation. Collectively, these results imply that ACAT1 is a potential therapeutic target, and cholesterol homeostasis is strongly related to glioma formation. This in vivo model provides several rapid and robust phenotypic readouts, allowing determination of the pathometabolic pathways involved in gliomagenesis, as well as providing valuable information for novel therapeutic strategies."
Monday, August 19, 2019
Fly study reveals potential mechanism of male vs. female differences in cancer malignancy
The histone code reader PHD finger protein 7 controls sex-linked disparities in gene expression and malignancy in Drosophila
Cristina Molnar, Jan Peter Heinen, Jose Reina, Salud Llamazares, Emilio Palumbo, Alessandra Breschi, Marina Gay, Laura Villarreal, Marta Vilaseca, Giulia Pollarolo and Cayetano Gonzalez
Science Advances 14 Aug 2019:
Vol. 5, no. 8, eaaw7965
DOI: 10.1126/sciadv.aaw7965
https://advances.sciencemag.org/content/5/8/eaaw7965.full
Abstract: "The notable male predominance across many human cancer types remains unexplained. Here, we show that Drosophila l(3)mbt brain tumors are more invasive and develop as malignant neoplasms more often in males than in females. By quantitative proteomics, we have identified a signature of proteins that are differentially expressed between male and female tumor samples. Prominent among them is the conserved chromatin reader PHD finger protein 7 (Phf7). We show that Phf7 depletion reduces sex-dependent differences in gene expression and suppresses the enhanced malignant traits of male tumors. Our results identify potential regulators of sex-linked tumor dimorphism and show that these genes may serve as targets to suppress sex-linked malignant traits."
Cristina Molnar, Jan Peter Heinen, Jose Reina, Salud Llamazares, Emilio Palumbo, Alessandra Breschi, Marina Gay, Laura Villarreal, Marta Vilaseca, Giulia Pollarolo and Cayetano Gonzalez
Science Advances 14 Aug 2019:
Vol. 5, no. 8, eaaw7965
DOI: 10.1126/sciadv.aaw7965
https://advances.sciencemag.org/content/5/8/eaaw7965.full
Abstract: "The notable male predominance across many human cancer types remains unexplained. Here, we show that Drosophila l(3)mbt brain tumors are more invasive and develop as malignant neoplasms more often in males than in females. By quantitative proteomics, we have identified a signature of proteins that are differentially expressed between male and female tumor samples. Prominent among them is the conserved chromatin reader PHD finger protein 7 (Phf7). We show that Phf7 depletion reduces sex-dependent differences in gene expression and suppresses the enhanced malignant traits of male tumors. Our results identify potential regulators of sex-linked tumor dimorphism and show that these genes may serve as targets to suppress sex-linked malignant traits."
Flies used to test drug activity predicted using dynamic combinatorial chemistry approach
Canal-Martín A, Sastre J, Sánchez-Barrena MJ, Canales A, Baldominos S, Pascual N, Martínez-González L, Molero D, Fernández-Valle ME, Sáez E, Blanco-Gabella P, Gómez-Rubio E, Martín-Santamaría S, Sáiz A, Mansilla A, Cañada FJ, Jiménez-Barbero J, Martínez A, Pérez-Fernández R. Insights into real-time chemical processes in a calcium sensor protein-directed dynamic library. Nat Commun. 2019 Jun 26;10(1):2798. PMID: 31243268; PMCID: PMC6595003.
Abstract: "Dynamic combinatorial chemistry (DCC) has proven its potential in drug discovery speeding the identification of modulators of biological targets. However, the exchange chemistries typically take place under specific reaction conditions, with limited tools capable of operating under physiological parameters. Here we report a catalyzed protein-directed DCC working at low temperatures that allows the calcium sensor NCS-1 to find the best ligands in situ. Ultrafast NMR identifies the reaction intermediates of the acylhydrazone exchange, tracing the molecular assemblies and getting a real-time insight into the essence of DCC processes at physiological pH. Additionally, NMR, X-ray crystallography and computational methods are employed to elucidate structural and mechanistic aspects of the molecular recognition event. The DCC approach leads us to the identification of a compound stabilizing the NCS-1/Ric8a complex and whose therapeutic potential is proven in a Drosophila model of disease with synaptic alterations."
Abstract: "Dynamic combinatorial chemistry (DCC) has proven its potential in drug discovery speeding the identification of modulators of biological targets. However, the exchange chemistries typically take place under specific reaction conditions, with limited tools capable of operating under physiological parameters. Here we report a catalyzed protein-directed DCC working at low temperatures that allows the calcium sensor NCS-1 to find the best ligands in situ. Ultrafast NMR identifies the reaction intermediates of the acylhydrazone exchange, tracing the molecular assemblies and getting a real-time insight into the essence of DCC processes at physiological pH. Additionally, NMR, X-ray crystallography and computational methods are employed to elucidate structural and mechanistic aspects of the molecular recognition event. The DCC approach leads us to the identification of a compound stabilizing the NCS-1/Ric8a complex and whose therapeutic potential is proven in a Drosophila model of disease with synaptic alterations."
Friday, June 28, 2019
Automated tracking of leg movement in free-moving flies contributes to characterization of fly models of neurodegenerative diseases
Wu S, Tan KJ, Govindarajan LN, Stewart JC, Gu L, Ho JWH, Katarya M, Wong BH, Tan EK, Li D, Claridge-Chang A, Libedinsky C, Cheng L, Aw SS. Fully automated leg tracking of Drosophila neurodegeneration models reveals distinct conserved movement signatures. PLoS Biol. 2019 Jun 27;17(6):e3000346. PubMed PMID: 31246996.
Abstract: "Some neurodegenerative diseases, like Parkinsons Disease (PD) and Spinocerebellar ataxia 3 (SCA3), are associated with distinct, altered gait and tremor movements that are reflective of the underlying disease etiology. Drosophila melanogaster models of neurodegeneration have illuminated our understanding of the molecular mechanisms of disease. However, it is unknown whether specific gait and tremor dysfunctions also occur in fly disease mutants. To answer this question, we developed a machine-learning image-analysis program, Feature Learning-based LImb segmentation and Tracking (FLLIT), that automatically tracks leg claw positions of freely moving flies recorded on high-speed video, producing a series of gait measurements. Notably, unlike other machine-learning methods, FLLIT generates its own training sets and does not require user-annotated images for learning. Using FLLIT, we carried out high-throughput and high-resolution analysis of gait and tremor features in Drosophila neurodegeneration mutants for the first time. We found that fly models of PD and SCA3 exhibited markedly different walking gait and tremor signatures, which recapitulated characteristics of the respective human diseases. Selective expression of mutant SCA3 in dopaminergic neurons led to a gait signature that more closely resembled those of PD flies. This suggests that the behavioral phenotype depends on the neurons affected rather than the specific nature of the mutation. Different mutations produced tremors in distinct leg pairs, indicating that different motor circuits were affected. Using this approach, fly models can be used to dissect the neurogenetic mechanisms that underlie movement disorders."
Abstract: "Some neurodegenerative diseases, like Parkinsons Disease (PD) and Spinocerebellar ataxia 3 (SCA3), are associated with distinct, altered gait and tremor movements that are reflective of the underlying disease etiology. Drosophila melanogaster models of neurodegeneration have illuminated our understanding of the molecular mechanisms of disease. However, it is unknown whether specific gait and tremor dysfunctions also occur in fly disease mutants. To answer this question, we developed a machine-learning image-analysis program, Feature Learning-based LImb segmentation and Tracking (FLLIT), that automatically tracks leg claw positions of freely moving flies recorded on high-speed video, producing a series of gait measurements. Notably, unlike other machine-learning methods, FLLIT generates its own training sets and does not require user-annotated images for learning. Using FLLIT, we carried out high-throughput and high-resolution analysis of gait and tremor features in Drosophila neurodegeneration mutants for the first time. We found that fly models of PD and SCA3 exhibited markedly different walking gait and tremor signatures, which recapitulated characteristics of the respective human diseases. Selective expression of mutant SCA3 in dopaminergic neurons led to a gait signature that more closely resembled those of PD flies. This suggests that the behavioral phenotype depends on the neurons affected rather than the specific nature of the mutation. Different mutations produced tremors in distinct leg pairs, indicating that different motor circuits were affected. Using this approach, fly models can be used to dissect the neurogenetic mechanisms that underlie movement disorders."
Drosophila studies used to follow up on results of epigenome-wide association studies (EWAS) related to Alzheimer's disease
Higham JP, Malik BR, Buhl E, Dawson JM, Ogier AS, Lunnon K, Hodge JJL. Alzheimer's Disease Associated Genes Ankyrin and Tau Cause Shortened Lifespan and Memory Loss in Drosophila. Front Cell Neurosci. 2019 Jun 11;13:260. PubMed PMID: 31244615; PubMed Central PMCID: PMC6581016.
From the abstract: "Alzheimer's disease (AD) is the most common form of dementia and is characterized by intracellular neurofibrillary tangles of hyperphosphorylated Tau, including the 0N4R isoform and accumulation of extracellular amyloid beta (Aβ) plaques. ... Recent epigenome-wide association studies (EWAS) of AD have identified a number of loci that are differentially methylated in the AD cortex. Indeed, hypermethylation and reduced expression of the Ankyrin 1 (ANK1) gene in AD has been reported in the cortex in numerous different post-mortem brain cohorts. ... We have generated Drosophila models to allow us to functionally characterize Drosophila Ank2, the ortholog of human ANK1 and to determine its interaction with human Tau and Aβ. ... we show that the mis-expression of Ank2 can drive disease relevant processes and phenocopy some features of AD. Therefore, we propose targeting human ANK1 may have therapeutic potential. This represents the first study to characterize an AD-relevant gene nominated from EWAS."
From the abstract: "Alzheimer's disease (AD) is the most common form of dementia and is characterized by intracellular neurofibrillary tangles of hyperphosphorylated Tau, including the 0N4R isoform and accumulation of extracellular amyloid beta (Aβ) plaques. ... Recent epigenome-wide association studies (EWAS) of AD have identified a number of loci that are differentially methylated in the AD cortex. Indeed, hypermethylation and reduced expression of the Ankyrin 1 (ANK1) gene in AD has been reported in the cortex in numerous different post-mortem brain cohorts. ... We have generated Drosophila models to allow us to functionally characterize Drosophila Ank2, the ortholog of human ANK1 and to determine its interaction with human Tau and Aβ. ... we show that the mis-expression of Ank2 can drive disease relevant processes and phenocopy some features of AD. Therefore, we propose targeting human ANK1 may have therapeutic potential. This represents the first study to characterize an AD-relevant gene nominated from EWAS."
Thursday, June 27, 2019
Fly model provides "first animal models for myosin-based Freeman-Sheldon syndrome (FSS)"
Rao DS, Kronert WA, Guo Y, Hsu KH, Sarsoza F, Bernstein SI. Reductions in ATPase activity, actin sliding velocity, and myofibril stability yield muscle dysfunction in Drosophila models of myosin-based Freeman-Sheldon syndrome. Mol Biol Cell. 2019 Jan 1;30(1):30-41. PubMed PMID: 30379605; PubMed Central PMCID: PMC6337914.
Abstract: "Using Drosophila melanogaster, we created the first animal models for myosin-based Freeman-Sheldon syndrome (FSS), a dominant form of distal arthrogryposis defined by congenital facial and distal skeletal muscle contractures. Electron microscopy of homozygous mutant indirect flight muscles showed normal (Y583S) or altered (T178I, R672C) myofibril assembly followed by progressive disruption of the myofilament lattice. In contrast, all alleles permitted normal myofibril assembly in the heterozygous state but caused myofibrillar disruption during aging. The severity of myofibril defects in heterozygotes correlated with the level of flight impairment. Thus our Drosophila models mimic the human condition in that FSS mutations are dominant and display varied degrees of phenotypic severity. Molecular modeling indicates that the mutations disrupt communication between the nucleotide-binding site of myosin and its lever arm that drives force production. Each mutant myosin showed reduced in vitro actin sliding velocity, with the two more severe alleles significantly decreasing the catalytic efficiency of actin-activated ATP hydrolysis. The observed reductions in actin motility and catalytic efficiency may serve as the mechanistic basis of the progressive myofibrillar disarray observed in the Drosophila models as well as the prolonged contractile activity responsible for skeletal muscle contractures in FSS patients."
Learn about Freeman-Sheldon syndrome online at the US NIH Genetic and Rare Diseases Information Center (GARD).
Abstract: "Using Drosophila melanogaster, we created the first animal models for myosin-based Freeman-Sheldon syndrome (FSS), a dominant form of distal arthrogryposis defined by congenital facial and distal skeletal muscle contractures. Electron microscopy of homozygous mutant indirect flight muscles showed normal (Y583S) or altered (T178I, R672C) myofibril assembly followed by progressive disruption of the myofilament lattice. In contrast, all alleles permitted normal myofibril assembly in the heterozygous state but caused myofibrillar disruption during aging. The severity of myofibril defects in heterozygotes correlated with the level of flight impairment. Thus our Drosophila models mimic the human condition in that FSS mutations are dominant and display varied degrees of phenotypic severity. Molecular modeling indicates that the mutations disrupt communication between the nucleotide-binding site of myosin and its lever arm that drives force production. Each mutant myosin showed reduced in vitro actin sliding velocity, with the two more severe alleles significantly decreasing the catalytic efficiency of actin-activated ATP hydrolysis. The observed reductions in actin motility and catalytic efficiency may serve as the mechanistic basis of the progressive myofibrillar disarray observed in the Drosophila models as well as the prolonged contractile activity responsible for skeletal muscle contractures in FSS patients."
Learn about Freeman-Sheldon syndrome online at the US NIH Genetic and Rare Diseases Information Center (GARD).
Parkinson's disease-related study in human cultured cells and Drosophila
Saridaki T, Nippold M, Dinter E, Roos A, Diederichs L, Fensky L, Schulz JB, Falkenburger BH. FYCO1 mediates clearance of α-synuclein aggregates through a Rab7-dependent mechanism. J Neurochem. 2018 Aug;146(4):474-492. PubMed PMID: 29747217.
From the abstract: "Parkinson's disease can be caused by mutations in the α-synuclein gene and is characterized by aggregates of α-synuclein protein. We have previously shown that over-expression of the small GTPase Rab7 can induce clearance of α-synuclein aggregates. In this study, we investigate which Rab7 effectors mediate this effect. To model Parkinson's disease, we expressed the pathogenic A53T mutant of α-synuclein in HEK293T cells and Drosophila melanogaster. ... Coexpression of FYCO1 in the fly model decreased α-synuclein aggregates as shown by the filter trap assay and rescued the locomotor deficit resulting from neuronal A53T-α-synuclein expression. ..."
From the abstract: "Parkinson's disease can be caused by mutations in the α-synuclein gene and is characterized by aggregates of α-synuclein protein. We have previously shown that over-expression of the small GTPase Rab7 can induce clearance of α-synuclein aggregates. In this study, we investigate which Rab7 effectors mediate this effect. To model Parkinson's disease, we expressed the pathogenic A53T mutant of α-synuclein in HEK293T cells and Drosophila melanogaster. ... Coexpression of FYCO1 in the fly model decreased α-synuclein aggregates as shown by the filter trap assay and rescued the locomotor deficit resulting from neuronal A53T-α-synuclein expression. ..."
Tuesday, June 25, 2019
Fly model of FTD used to identify compound reported to reduce toxic phosphorylated tau
Shim KH, Kim SH, Hur J, Kim DH, Demirev AV, Yoon SY. Small-molecule drug screening identifies drug Ro 31-8220 that reduces toxic phosphorylated tau in Drosophila melanogaster. Neurobiol Dis. 2019 Jun 21:104519. doi: 10.1016/j.nbd.2019.104519. PMID: 31233882.
Abstract: "The intraneuronal aggregates of hyperphosphorylated and misfolded tau (neurofibrillary tangles, NFTs) cause a stereotypical spatiotemporal Alzheimer's disease (AD) progression that correlates with the severity of the associated cognitive decline. Kinase activity contributes to the balance between neuron survival and cell death. Hyperactivation of kinases including the conventional protein kinase C (PKC) is a defective molecular event accompanying associative memory loss, tau phosphorylation, and progression of AD or related neurodegenerative diseases. Here, we investigated the ability of small therapeutic compounds (a custom library) to improve tau-induced rough-eye phenotype in a Drosophila melanogaster model of frontotemporal dementia. We also assessed the tau phosphorylation in vivo and selected hit compounds. Among the potential hits, we investigated Ro 31-8220, described earlier as a potent PKCα inhibitor. Ro 31-8220 robustly improved the rough-eye phenotype, reduced phosphorylated tau species in vitro and in vivo, reversed tau-induced memory impairment, and improved the fly motor functions. In a human neuroblastoma cell line, Ro 31-8220 reduced the PKC activity and the tau phosphorylation pattern, but we also have to acknowledge the compound's wide range of biological activity. Nevertheless, Ro 31-8220 is a novel therapeutic mitigator of tau-induced neurotoxocity."
Abstract: "The intraneuronal aggregates of hyperphosphorylated and misfolded tau (neurofibrillary tangles, NFTs) cause a stereotypical spatiotemporal Alzheimer's disease (AD) progression that correlates with the severity of the associated cognitive decline. Kinase activity contributes to the balance between neuron survival and cell death. Hyperactivation of kinases including the conventional protein kinase C (PKC) is a defective molecular event accompanying associative memory loss, tau phosphorylation, and progression of AD or related neurodegenerative diseases. Here, we investigated the ability of small therapeutic compounds (a custom library) to improve tau-induced rough-eye phenotype in a Drosophila melanogaster model of frontotemporal dementia. We also assessed the tau phosphorylation in vivo and selected hit compounds. Among the potential hits, we investigated Ro 31-8220, described earlier as a potent PKCα inhibitor. Ro 31-8220 robustly improved the rough-eye phenotype, reduced phosphorylated tau species in vitro and in vivo, reversed tau-induced memory impairment, and improved the fly motor functions. In a human neuroblastoma cell line, Ro 31-8220 reduced the PKC activity and the tau phosphorylation pattern, but we also have to acknowledge the compound's wide range of biological activity. Nevertheless, Ro 31-8220 is a novel therapeutic mitigator of tau-induced neurotoxocity."
Monday, June 24, 2019
Drugs, stones, and flies -- high-throughput screen in fly disease model identifies potential therapeutic for prevention of kidney stones
Ali SN, Dayarathna TK, Ali AN, Osumah T, Ahmed M, Cooper TT, Power NE, Zhang D, Kim D, Kim R, St Amant A, Hou J, Tailly T, Yang J, Luyt L, Spagnuolo PA, Burton JP, Razvi H, Leong HS. Drosophila melanogaster as a function-based high-throughput screening model for antinephrolithiasis agents in kidney stone patients. Dis Model Mech. 2018 Nov 16;11(11). pii: dmm035873. doi: 10.1242/dmm.035873. PubMed PMID: 30082495; PubMed Central PMCID: PMC6262805.
Abstract: "Kidney stone disease involves the aggregation of stone-forming salts consequent to solute supersaturation in urine. The development of novel therapeutic agents for this predominantly metabolic and biochemical disorder have been hampered by the lack of a practical pre-clinical model amenable to drug screening. Here, Drosophila melanogaster, an emerging model for kidney stone disease research, was adapted as a high-throughput functional drug screening platform independent of the multifactorial nature of mammalian nephrolithiasis. Through functional screening, the therapeutic potential of a novel compound commonly known as arbutin that specifically binds to oxalate, a key component of kidney calculi, was identified. Through isothermal titration calorimetry, high-performance liquid chromatography and atomic force microscopy, arbutin was determined to interact with calcium and oxalate in both free and bound states, disrupting crystal lattice structure, growth and crystallization. When used to treat patient urine samples, arbutin significantly abrogated calculus formation in vivo and outperformed potassium citrate in low pH urine conditions, owing to its oxalate-centric mode of action. The discovery of this novel antilithogenic compound via D. melanogaster, independent of a mammalian model, brings greater recognition to this platform, for which metabolic features are primary outcomes, underscoring the power of D. melanogaster as a high-throughput drug screening platform in similar disorders. This is the first description of the use of D. melanogaster as the model system for a high-throughput chemical library screen. This article has an associated First Person interview with the first authors of the paper."
Abstract: "Kidney stone disease involves the aggregation of stone-forming salts consequent to solute supersaturation in urine. The development of novel therapeutic agents for this predominantly metabolic and biochemical disorder have been hampered by the lack of a practical pre-clinical model amenable to drug screening. Here, Drosophila melanogaster, an emerging model for kidney stone disease research, was adapted as a high-throughput functional drug screening platform independent of the multifactorial nature of mammalian nephrolithiasis. Through functional screening, the therapeutic potential of a novel compound commonly known as arbutin that specifically binds to oxalate, a key component of kidney calculi, was identified. Through isothermal titration calorimetry, high-performance liquid chromatography and atomic force microscopy, arbutin was determined to interact with calcium and oxalate in both free and bound states, disrupting crystal lattice structure, growth and crystallization. When used to treat patient urine samples, arbutin significantly abrogated calculus formation in vivo and outperformed potassium citrate in low pH urine conditions, owing to its oxalate-centric mode of action. The discovery of this novel antilithogenic compound via D. melanogaster, independent of a mammalian model, brings greater recognition to this platform, for which metabolic features are primary outcomes, underscoring the power of D. melanogaster as a high-throughput drug screening platform in similar disorders. This is the first description of the use of D. melanogaster as the model system for a high-throughput chemical library screen. This article has an associated First Person interview with the first authors of the paper."
Drosophila as "a fundamental genetic model to identify new disease-causing variants" -- review from Bellen, Wangler & Yamamoto
Bellen HJ, Wangler MF, Yamamoto S. The fruit fly at the interface of diagnosis and pathogenic mechanisms of rare and common human diseases. Hum Mol Genet. 2019 Jun 22. pii: ddz135. doi: 10.1093/hmg/ddz135. PubMed PMID: 31227826.
Abstract: "Drosophila melanogaster is a unique, powerful genetic model organism for studying a broad range of biological questions. Human studies that probe the genetic causes of rare and undiagnosed diseases using massive-parallel sequencing often require complementary gene function studies to determine if and how rare variants affect gene function. These studies also provide inroads to disease mechanisms and therapeutic targets. In this review we discuss strategies for functional studies of rare human variants in Drosophila. We focus on our experience in establishing a Drosophila Core for the Model Organisms Screening Center (MOSC) for the Undiagnosed Diseases Network (UDN) and concurrent fly studies with other large genomic rare disease research efforts such as the Centers for Mendelian Genomics (CMG). We outline four major strategies that use the latest technology in fly genetics to understand the impact of human variants on gene function. We also mention general concepts in probing disease mechanisms, therapeutics and using rare disease to understand common diseases. Drosophila is and will continue to be a fundamental genetic model to identify new disease-causing variants, pathogenic mechanisms and drugs that will impact medicine."
Abstract: "Drosophila melanogaster is a unique, powerful genetic model organism for studying a broad range of biological questions. Human studies that probe the genetic causes of rare and undiagnosed diseases using massive-parallel sequencing often require complementary gene function studies to determine if and how rare variants affect gene function. These studies also provide inroads to disease mechanisms and therapeutic targets. In this review we discuss strategies for functional studies of rare human variants in Drosophila. We focus on our experience in establishing a Drosophila Core for the Model Organisms Screening Center (MOSC) for the Undiagnosed Diseases Network (UDN) and concurrent fly studies with other large genomic rare disease research efforts such as the Centers for Mendelian Genomics (CMG). We outline four major strategies that use the latest technology in fly genetics to understand the impact of human variants on gene function. We also mention general concepts in probing disease mechanisms, therapeutics and using rare disease to understand common diseases. Drosophila is and will continue to be a fundamental genetic model to identify new disease-causing variants, pathogenic mechanisms and drugs that will impact medicine."
Tuesday, May 28, 2019
Drosophila study identifies genes relevant to consumption of drugs of abuse
Highfill CA, Baker BM, Stevens SD, Anholt RRH, Mackay TFC. Genetics of cocaine and methamphetamine consumption and preference in Drosophila melanogaster. PLoS Genet. 2019 May 20;15(5):e1007834. PMID: 31107875.
From the abstract: "Illicit use of psychostimulants, such as cocaine and methamphetamine, constitutes a significant public health problem. ... genetic factors that account for individual variation in susceptibility to substance abuse and addiction remain largely unknown. Drosophila melanogaster can serve as a translational model for studies on substance abuse, since flies have a dopamine transporter that can bind cocaine and methamphetamine, and exposure to these compounds elicits effects similar to those observed in people, suggesting conserved evolutionary mechanisms underlying drug responses. Here, we used the D. melanogaster Genetic Reference Panel to investigate the genetic basis for variation in psychostimulant drug consumption ... Quantification of natural genetic variation in voluntary consumption, preference, and change in consumption and preference over time for cocaine and methamphetamine uncovered significant genetic variation for all traits, including sex-, exposure- and drug-specific genetic variation. Genome wide association analyses identified both shared and drug-specific candidate genes ... "
From the abstract: "Illicit use of psychostimulants, such as cocaine and methamphetamine, constitutes a significant public health problem. ... genetic factors that account for individual variation in susceptibility to substance abuse and addiction remain largely unknown. Drosophila melanogaster can serve as a translational model for studies on substance abuse, since flies have a dopamine transporter that can bind cocaine and methamphetamine, and exposure to these compounds elicits effects similar to those observed in people, suggesting conserved evolutionary mechanisms underlying drug responses. Here, we used the D. melanogaster Genetic Reference Panel to investigate the genetic basis for variation in psychostimulant drug consumption ... Quantification of natural genetic variation in voluntary consumption, preference, and change in consumption and preference over time for cocaine and methamphetamine uncovered significant genetic variation for all traits, including sex-, exposure- and drug-specific genetic variation. Genome wide association analyses identified both shared and drug-specific candidate genes ... "
Friday, May 24, 2019
Fly studies help provide insights into role of nucleocytoplasmic transport in ALS/FTD
Chou CC, Zhang Y, Umoh ME, Vaughan SW, Lorenzini I, Liu F, Sayegh M, Donlin-Asp PG, Chen YH, Duong DM, Seyfried NT, Powers MA, Kukar T, Hales CM, Gearing M, Cairns NJ, Boylan KB, Dickson DW, Rademakers R, Zhang YJ, Petrucelli L, Sattler R, Zarnescu DC, Glass JD, Rossoll W. TDP-43 pathology disrupts nuclear pore complexes and nucleocytoplasmic transport in ALS/FTD. Nat Neurosci. 2018 Feb;21(2):228-239. doi: 10.1038/s41593-017-0047-3. Epub 2018 Jan 8. PubMed PMID: 29311743; PubMed Central PMCID: PMC5800968.
Abstract: "The cytoplasmic mislocalization and aggregation of TAR DNA-binding protein-43 (TDP-43) is a common histopathological hallmark of the amyotrophic lateral sclerosis and frontotemporal dementia disease spectrum (ALS/FTD). However, the composition of aggregates and their contribution to the disease process remain unknown. Here we used proximity-dependent biotin identification (BioID) to interrogate the interactome of detergent-insoluble TDP-43 aggregates and found them enriched for components of the nuclear pore complex and nucleocytoplasmic transport machinery. Aggregated and disease-linked mutant TDP-43 triggered the sequestration and/or mislocalization of nucleoporins and transport factors, and interfered with nuclear protein import and RNA export in mouse primary cortical neurons, human fibroblasts and induced pluripotent stem cell-derived neurons. Nuclear pore pathology is present in brain tissue in cases of sporadic ALS and those involving genetic mutations in TARDBP and C9orf72. Our data strongly implicate TDP-43-mediated nucleocytoplasmic transport defects as a common disease mechanism in ALS/FTD."
See also comment in Nature Neuroscience.
Abstract: "The cytoplasmic mislocalization and aggregation of TAR DNA-binding protein-43 (TDP-43) is a common histopathological hallmark of the amyotrophic lateral sclerosis and frontotemporal dementia disease spectrum (ALS/FTD). However, the composition of aggregates and their contribution to the disease process remain unknown. Here we used proximity-dependent biotin identification (BioID) to interrogate the interactome of detergent-insoluble TDP-43 aggregates and found them enriched for components of the nuclear pore complex and nucleocytoplasmic transport machinery. Aggregated and disease-linked mutant TDP-43 triggered the sequestration and/or mislocalization of nucleoporins and transport factors, and interfered with nuclear protein import and RNA export in mouse primary cortical neurons, human fibroblasts and induced pluripotent stem cell-derived neurons. Nuclear pore pathology is present in brain tissue in cases of sporadic ALS and those involving genetic mutations in TARDBP and C9orf72. Our data strongly implicate TDP-43-mediated nucleocytoplasmic transport defects as a common disease mechanism in ALS/FTD."
See also comment in Nature Neuroscience.
How to lurk: Droosphila used in study related to attachment of the cholera-causing bacteria Vibrio cholerae to arthropod intestines
Kamareddine L, Wong ACN, Vanhove AS, Hang S, Purdy AE, Kierek-Pearson K, Asara JM, Ali A, Morris JG Jr, Watnick PI. Activation of Vibrio cholerae quorum sensing promotes survival of an arthropod host. Nat Microbiol. 2018 Feb;3(2):243-252. PMID: 29180725; PMCID: PMC6260827.
Abstract: "Vibrio cholerae colonizes the human terminal ileum to cause cholera, and the arthropod intestine and exoskeleton to persist in the aquatic environment. Attachment to these surfaces is regulated by the bacterial quorum-sensing signal transduction cascade, which allows bacteria to assess the density of microbial neighbours. Intestinal colonization with V. cholerae results in expenditure of host lipid stores in the model arthropod Drosophila melanogaster. Here we report that activation of quorum sensing in the Drosophila intestine retards this process by repressing V. cholerae succinate uptake. Increased host access to intestinal succinate mitigates infection-induced lipid wasting to extend survival of V. cholerae-infected flies. Therefore, quorum sensing promotes a more favourable interaction between V. cholerae and an arthropod host by reducing the nutritional burden of intestinal colonization."
Abstract: "Vibrio cholerae colonizes the human terminal ileum to cause cholera, and the arthropod intestine and exoskeleton to persist in the aquatic environment. Attachment to these surfaces is regulated by the bacterial quorum-sensing signal transduction cascade, which allows bacteria to assess the density of microbial neighbours. Intestinal colonization with V. cholerae results in expenditure of host lipid stores in the model arthropod Drosophila melanogaster. Here we report that activation of quorum sensing in the Drosophila intestine retards this process by repressing V. cholerae succinate uptake. Increased host access to intestinal succinate mitigates infection-induced lipid wasting to extend survival of V. cholerae-infected flies. Therefore, quorum sensing promotes a more favourable interaction between V. cholerae and an arthropod host by reducing the nutritional burden of intestinal colonization."
Asking yourself, "Um, what?" Here's an interpretation by your blog author:
Bacteria called Vibrio cholerae cause cholera in humans. When they're not doing that, they lurk inside the guts (and on the outsides) of arthropods that live in the water. This study uses fruit flies as a lab-friendly system in which to look at a specific aspect of the interaction between a host arthropod's gut and Vibrio bacteria. Turns out that confusing the bacteria about how many of themselves are around stops them from taking up a molecule called succinate, leaving more of the succinate around for the fly. With more succinate available, the fly uses up less of its fat reserves than it usually would when infected. This helps the infected fly survive longer.
Personalized platform that includes a complex fly genetic model used to identify a treatment strategy for a specific patient
A personalized platform identifies trametinib plus zoledronate for a patient with KRAS-mutant metastatic colorectal cancer.
Erdem Bangi1,*, Celina Ang2,3, Peter Smibert1,†, Andrew V. Uzilov4,5, Alexander G. Teague1, Yevgeniy Antipin4,5, Rong Chen4,5, Chana Hecht1, Nelson Gruszczynski1,‡, Wesley J. Yon1, Denis Malyshev1, Denise Laspina1, Isaiah Selkridge2, Hope Rainey2, Aye S. Moe4,5, Chun Yee Lau4,5, Patricia Taik4,5, Eric Wilck6, Aarti Bhardwaj2, Max Sung2,3, Sara Kim7, Kendra Yum7, Robert Sebra4,5, Michael Donovan3,8, Krzysztof Misiukiewicz2,3, Eric E. Schadt4,5,3, Marshall R. Posner2,3 and Ross L. Cagan1,3,§
1Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
2Division of Hematology and Medical Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
3Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
4Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
5SEMA4, a Mount Sinai Venture, 333 Ludlow Street, South Tower, 3rd floor, Stamford, CT 06902, USA.
6Department of Radiology, The Mount Sinai Hospital, New York, NY 10029, USA.
7Department of Pharmacy, The Mount Sinai Hospital, New York, NY 10029, USA.
8Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
Abstract: "Colorectal cancer remains a leading source of cancer mortality worldwide. Initial response is often followed by emergent resistance that is poorly responsive to targeted therapies, reflecting currently undruggable cancer drivers such as KRAS and overall genomic complexity. Here, we report a novel approach to developing a personalized therapy for a patient with treatment-resistant metastatic KRAS-mutant colorectal cancer. An extensive genomic analysis of the tumor’s genomic landscape identified nine key drivers. A transgenic model that altered orthologs of these nine genes in the Drosophila hindgut was developed; a robotics-based screen using this platform identified trametinib plus zoledronate as a candidate treatment combination. Treating the patient led to a significant response: Target and nontarget lesions displayed a strong partial response and remained stable for 11 months. By addressing a disease’s genomic complexity, this personalized approach may provide an alternative treatment option for recalcitrant disease such as KRAS-mutant colorectal cancer."
Erdem Bangi1,*, Celina Ang2,3, Peter Smibert1,†, Andrew V. Uzilov4,5, Alexander G. Teague1, Yevgeniy Antipin4,5, Rong Chen4,5, Chana Hecht1, Nelson Gruszczynski1,‡, Wesley J. Yon1, Denis Malyshev1, Denise Laspina1, Isaiah Selkridge2, Hope Rainey2, Aye S. Moe4,5, Chun Yee Lau4,5, Patricia Taik4,5, Eric Wilck6, Aarti Bhardwaj2, Max Sung2,3, Sara Kim7, Kendra Yum7, Robert Sebra4,5, Michael Donovan3,8, Krzysztof Misiukiewicz2,3, Eric E. Schadt4,5,3, Marshall R. Posner2,3 and Ross L. Cagan1,3,§
1Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
2Division of Hematology and Medical Oncology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
3Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
4Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
5SEMA4, a Mount Sinai Venture, 333 Ludlow Street, South Tower, 3rd floor, Stamford, CT 06902, USA.
6Department of Radiology, The Mount Sinai Hospital, New York, NY 10029, USA.
7Department of Pharmacy, The Mount Sinai Hospital, New York, NY 10029, USA.
8Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
Abstract: "Colorectal cancer remains a leading source of cancer mortality worldwide. Initial response is often followed by emergent resistance that is poorly responsive to targeted therapies, reflecting currently undruggable cancer drivers such as KRAS and overall genomic complexity. Here, we report a novel approach to developing a personalized therapy for a patient with treatment-resistant metastatic KRAS-mutant colorectal cancer. An extensive genomic analysis of the tumor’s genomic landscape identified nine key drivers. A transgenic model that altered orthologs of these nine genes in the Drosophila hindgut was developed; a robotics-based screen using this platform identified trametinib plus zoledronate as a candidate treatment combination. Treating the patient led to a significant response: Target and nontarget lesions displayed a strong partial response and remained stable for 11 months. By addressing a disease’s genomic complexity, this personalized approach may provide an alternative treatment option for recalcitrant disease such as KRAS-mutant colorectal cancer."
Read the article at Science Advances.
See also, coverage of the story in The Scientist.
Sunday, May 12, 2019
Outreach online -- podcast series introduces Drosophila research
Need a primer on fruit fly research basics? Check out blog author Stephanie Mohr on a four-part 'fruit fly Friday' podcast series aired by the Curiosity Daily Podcast.
Tuesday, April 30, 2019
Fly model related to Fragile X syndrome used to explore cellular mechanism
Sears JC, Choi WJ, Broadie K. Fragile X Mental Retardation Protein positively regulates PKA anchor Rugose and PKA activity to control actin assembly in learning/memory circuitry. Neurobiol Dis. 2019 Feb 13;127:53-64. PMID: 30771457.
From the abstract: "Recent work shows Fragile X Mental Retardation Protein (FMRP) drives the translation of very large proteins (>2000 aa) mediating neurodevelopment. Loss of function results in Fragile X syndrome (FXS), the leading heritable cause of intellectual disability (ID) and autism spectrum disorder (ASD). Using the Drosophila FXS disease model, we discover FMRP positively regulates the translation of the very large A-Kinase Anchor Protein (AKAP) Rugose (>3000 aa), homolog of ASD-associated human Neurobeachin (NBEA). ... Here, we link two ASD states; Neurobeachin (NBEA) associated ASD and Fragile X syndrome (FXS), the most common inherited ASD. Using established Drosophila disease models, we find Fragile X Mental Retardation Protein (FMRP) positively regulates translation of NBEA homolog Rugose, consistent with a recent advance showing FMRP promotes translation of very large proteins associated with ASD."
From the abstract: "Recent work shows Fragile X Mental Retardation Protein (FMRP) drives the translation of very large proteins (>2000 aa) mediating neurodevelopment. Loss of function results in Fragile X syndrome (FXS), the leading heritable cause of intellectual disability (ID) and autism spectrum disorder (ASD). Using the Drosophila FXS disease model, we discover FMRP positively regulates the translation of the very large A-Kinase Anchor Protein (AKAP) Rugose (>3000 aa), homolog of ASD-associated human Neurobeachin (NBEA). ... Here, we link two ASD states; Neurobeachin (NBEA) associated ASD and Fragile X syndrome (FXS), the most common inherited ASD. Using established Drosophila disease models, we find Fragile X Mental Retardation Protein (FMRP) positively regulates translation of NBEA homolog Rugose, consistent with a recent advance showing FMRP promotes translation of very large proteins associated with ASD."
Cross-species approach to "mining druggable modifiers of disease-associated proteins"
Huichalaf CH, Al-Ramahi I, Park KW, Grunke SD, Lu N, Haro M, El-Zein K, Gallego-Flores T, Perez AM, Jung SY, Botas J, Zoghbi HY, Jankowsky JL. Cross-species genetic screens to identify kinase targets for APP reduction in Alzheimer's disease. Hum Mol Genet. 2019 Feb 12. PMID: 30753434.
Abstract: "An early hallmark of Alzheimer's disease is the accumulation of amyloid-β, inspiring numerous therapeutic strategies targeting this peptide. An alternative approach is to destabilize the amyloid precursor protein (APP) from which Aβ is derived. We interrogated innate pathways governing APP stability using a siRNA screen for modifiers whose own reduction diminished APP in human cell lines and transgenic Drosophila. As proof-of-principle, we validated PKCβ - a known modifier identified by the screen - in an APP transgenic mouse model. PKCβ was genetically targeted using a novel AAV shuttle vector to deliver microRNA-adapted shRNA via intracranial injection. In vivo reduction of PKCβ initially diminished APP and delayed plaque formation. Despite persistent PKCβ suppression, the effect on APP and amyloid diminished over time. Our study advances this approach for mining druggable modifiers of disease-associated proteins, while cautioning that prolonged in vivo validation may be needed to reveal emergent limitations on efficacy."
Abstract: "An early hallmark of Alzheimer's disease is the accumulation of amyloid-β, inspiring numerous therapeutic strategies targeting this peptide. An alternative approach is to destabilize the amyloid precursor protein (APP) from which Aβ is derived. We interrogated innate pathways governing APP stability using a siRNA screen for modifiers whose own reduction diminished APP in human cell lines and transgenic Drosophila. As proof-of-principle, we validated PKCβ - a known modifier identified by the screen - in an APP transgenic mouse model. PKCβ was genetically targeted using a novel AAV shuttle vector to deliver microRNA-adapted shRNA via intracranial injection. In vivo reduction of PKCβ initially diminished APP and delayed plaque formation. Despite persistent PKCβ suppression, the effect on APP and amyloid diminished over time. Our study advances this approach for mining druggable modifiers of disease-associated proteins, while cautioning that prolonged in vivo validation may be needed to reveal emergent limitations on efficacy."
Flies used as living test tube to study genes implicated in long lifespan
Xiao FH, Chen XQ, Yu Q, Ye Y, Liu YW, Yan D, Yang LQ, Chen G, Lin R, Yang L, Liao X, Zhang W, Zhang W, Tang NL, Wang XF, Zhou J, Cai WW, He YH, Kong QP. Transcriptome evidence reveals enhanced autophagy-lysosomal function in centenarians. Genome Res. 2018 Nov;28(11):1601-1610. PMID: 30352807; PMCID: PMC6211641.
From the abstract: "... Here, we analyzed the transcriptomes of 76 centenarians, 54 centenarian-children, and 41 spouses of centenarian-children by RNA sequencing and found that ... the autophagy-lysosomal pathway is significantly up-regulated. Overexpression of several genes from this pathway, CTSB, ATP6V0C, ATG4D, and WIPI1, could promote autophagy and delay senescence in cultured IMR-90 cells, while overexpression of the Drosophila homolog of WIPI1, Atg18a, extended the life span in transgenic flies. ... these findings ... suggest that the enhanced waste-cleaning activity via autophagy may serve as a conserved mechanism to prolong the life span from Drosophila to humans."
From the abstract: "... Here, we analyzed the transcriptomes of 76 centenarians, 54 centenarian-children, and 41 spouses of centenarian-children by RNA sequencing and found that ... the autophagy-lysosomal pathway is significantly up-regulated. Overexpression of several genes from this pathway, CTSB, ATP6V0C, ATG4D, and WIPI1, could promote autophagy and delay senescence in cultured IMR-90 cells, while overexpression of the Drosophila homolog of WIPI1, Atg18a, extended the life span in transgenic flies. ... these findings ... suggest that the enhanced waste-cleaning activity via autophagy may serve as a conserved mechanism to prolong the life span from Drosophila to humans."
New fly model for understanding cognitive deficits associated with disruption of FOXP genes
Castells-Nobau A, Eidhof I, Fenckova M, Brenman-Suttner DB, Scheffer-de Gooyert JM, Christine S, Schellevis RL, van der Laan K, Quentin C, van Ninhuijs L, Hofmann F, Ejsmont R, Fisher SE, Kramer JM, Sigrist SJ, Simon AF, Schenck A. Conserved regulation of neurodevelopmental processes and behavior by FoxP in Drosophila. PLoS One. 2019 Feb 12;14(2):e0211652. PMID: 30753188; PMCID: PMC6372147.
From the abstract: "FOXP proteins form a subfamily of evolutionarily conserved transcription factors ... In humans, mutations in FOXP1 and FOXP2 have been implicated in cognitive deficits including intellectual disability and speech disorders. Drosophila exhibits a single ortholog, called FoxP ... Here we show that the dimerization property required for mammalian FOXP function is conserved in Drosophila. In flies, FoxP is enriched in the adult brain, showing strong expression in ~1000 neurons of cholinergic, glutamatergic and GABAergic nature. ... At the cellular level, ... Drosophila FoxP is required in larvae for synaptic morphogenesis at axonal terminals of the neuromuscular junction and for dendrite development of dorsal multidendritic sensory neurons. In the developing brain, we find that FoxP plays important roles in α-lobe mushroom body formation. Finally, at a behavioral level, we show that Drosophila FoxP is important for locomotion, habituation learning and social space behavior of adult flies. Our work shows that Drosophila FoxP is important for regulating several neurodevelopmental processes and behaviors that are related to human disease or vertebrate disease model phenotypes. This suggests a high degree of functional conservation with vertebrate FOXP orthologues and established flies as a model system for understanding FOXP related pathologies."
From the abstract: "FOXP proteins form a subfamily of evolutionarily conserved transcription factors ... In humans, mutations in FOXP1 and FOXP2 have been implicated in cognitive deficits including intellectual disability and speech disorders. Drosophila exhibits a single ortholog, called FoxP ... Here we show that the dimerization property required for mammalian FOXP function is conserved in Drosophila. In flies, FoxP is enriched in the adult brain, showing strong expression in ~1000 neurons of cholinergic, glutamatergic and GABAergic nature. ... At the cellular level, ... Drosophila FoxP is required in larvae for synaptic morphogenesis at axonal terminals of the neuromuscular junction and for dendrite development of dorsal multidendritic sensory neurons. In the developing brain, we find that FoxP plays important roles in α-lobe mushroom body formation. Finally, at a behavioral level, we show that Drosophila FoxP is important for locomotion, habituation learning and social space behavior of adult flies. Our work shows that Drosophila FoxP is important for regulating several neurodevelopmental processes and behaviors that are related to human disease or vertebrate disease model phenotypes. This suggests a high degree of functional conservation with vertebrate FOXP orthologues and established flies as a model system for understanding FOXP related pathologies."
Article addresses the importance of standardized diets in fly studies related to nutrition research
Lüersen K, Röder T, Rimbach G. Drosophila melanogaster in nutrition research-the importance of standardizing experimental diets. Genes Nutr. 2019 Feb 1;14:3. doi: 10.1186/s12263-019-0627-9. eCollection 2019. Review. PubMed PMID: 30766617; PubMed Central PMCID: PMC6359822.
Abstract: "The fruit fly Drosophila melanogaster has been increasingly recognized as an important model organism in nutrition research. In order to conduct nutritional studies in fruit flies, special attention should be given to the composition of the experimental diets. Besides complex diets, which are often based on maize, yeast, sucrose, and agar, Drosophila can be also fed chemically defined diets. These so-called holidic diets are standardized in terms of their macro- and micronutrient composition although the quantitative nutrient requirements of flies have yet not been fully established and warrant further investigations. For instance, only few studies address the fatty acid, vitamin, mineral, and trace element requirements of fruit flies. D. melanogaster may be also of interest in the field of nutritional medicine. Diet-induced diabetes and obesity models have been established, and in this context, often, the so-called high-fat and high-sugar diets are fed. However, the composition of these diets is not sufficiently defined and varies between studies. A consensus within the scientific community needs to be reached to standardize the exact composition of experimental complex and holidic diets for D. melanogaster in nutrition research. Since D. melanogaster is an established valuable model system for numerous human diseases, standardized diets are also a prerequisite to conduct diet-disease interaction studies. We suggest that a comprehensive approach, which combines deep phenotyping with disease-related Drosophila models under defined dietary conditions, might lead to the foundation of a so-called fly clinic."
Abstract: "The fruit fly Drosophila melanogaster has been increasingly recognized as an important model organism in nutrition research. In order to conduct nutritional studies in fruit flies, special attention should be given to the composition of the experimental diets. Besides complex diets, which are often based on maize, yeast, sucrose, and agar, Drosophila can be also fed chemically defined diets. These so-called holidic diets are standardized in terms of their macro- and micronutrient composition although the quantitative nutrient requirements of flies have yet not been fully established and warrant further investigations. For instance, only few studies address the fatty acid, vitamin, mineral, and trace element requirements of fruit flies. D. melanogaster may be also of interest in the field of nutritional medicine. Diet-induced diabetes and obesity models have been established, and in this context, often, the so-called high-fat and high-sugar diets are fed. However, the composition of these diets is not sufficiently defined and varies between studies. A consensus within the scientific community needs to be reached to standardize the exact composition of experimental complex and holidic diets for D. melanogaster in nutrition research. Since D. melanogaster is an established valuable model system for numerous human diseases, standardized diets are also a prerequisite to conduct diet-disease interaction studies. We suggest that a comprehensive approach, which combines deep phenotyping with disease-related Drosophila models under defined dietary conditions, might lead to the foundation of a so-called fly clinic."
Autophagy, lysosomes, and ALS/FTD
Şentürk M, Mao D, Bellen HJ. Loss of proteins associated with amyotrophic lateral sclerosis affect lysosomal acidification via different routes. Autophagy. 2019 Apr 28:1-3. PubMed
PMID: 31032688.
Abstract: "Abnormal accumulation of proteins is a hallmark of a variety of neurological diseases including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Maintenance of protein homeostasis (proteostasis) in neurons via proteasomal and macroautophagy/autophagy-lysosomal degradation is thought to be central for proper neuronal function and survival. We recently reported evolutionarily conserved roles for two ALS-linked proteins, UBQLN2 (ubiquilin 2) and VAPB, in regulation of lysosomal degradation. Ubiquilins are required for v-ATPase-mediated lysosomal acidification, whereas VAPs are required for the PtdIns4P-mediated endo-lysosomal trafficking pathway."
PMID: 31032688.
Abstract: "Abnormal accumulation of proteins is a hallmark of a variety of neurological diseases including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Maintenance of protein homeostasis (proteostasis) in neurons via proteasomal and macroautophagy/autophagy-lysosomal degradation is thought to be central for proper neuronal function and survival. We recently reported evolutionarily conserved roles for two ALS-linked proteins, UBQLN2 (ubiquilin 2) and VAPB, in regulation of lysosomal degradation. Ubiquilins are required for v-ATPase-mediated lysosomal acidification, whereas VAPs are required for the PtdIns4P-mediated endo-lysosomal trafficking pathway."
Review -- Drosophila models for the study of motor neuron diseases
Walters R, Manion J, Neely GG. Dissecting Motor Neuron Disease With Drosophila melanogaster. Front Neurosci. 2019 Apr 12;13:331. doi: 10.3389/fnins.2019.00331. PMID: 31031583; PMCID: PMC6473072.
Abstract: "Motor Neuron Disease (MND) typically affects patients during the later stages of life, and thus, MND is having an increasingly devastating impact on diagnosed individuals, their families and society. The umbrella term MND refers to diseases which cause the progressive loss of upper and/or lower motor neurons and a subsequent decrease in motor ability such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). The study of these diseases is complex and has recently involved the use of genome-wide association studies (GWAS). However, in the case of MND, it has been difficult to identify the complex genetics involved in subtypes, and functional investigation of new candidate disease genes is warranted. Drosophila is a powerful model for addressing these complex diseases. The UAS/Gal4/Gal80 system allows for the upregulation of Drosophila genes, the "knockdown" of genes and the ectopic expression of human genes or mutations in a tissue-specific manner; often resulting in Drosophila models which exhibit typical MND disease pathologies. These can then be further interrogated to identify disease-modifying genes or mutations and disease pathways. This review will discuss two common MNDs and the current Drosophila models which are being used to research their genetic basis and the different pathologies of MND."
Abstract: "Motor Neuron Disease (MND) typically affects patients during the later stages of life, and thus, MND is having an increasingly devastating impact on diagnosed individuals, their families and society. The umbrella term MND refers to diseases which cause the progressive loss of upper and/or lower motor neurons and a subsequent decrease in motor ability such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). The study of these diseases is complex and has recently involved the use of genome-wide association studies (GWAS). However, in the case of MND, it has been difficult to identify the complex genetics involved in subtypes, and functional investigation of new candidate disease genes is warranted. Drosophila is a powerful model for addressing these complex diseases. The UAS/Gal4/Gal80 system allows for the upregulation of Drosophila genes, the "knockdown" of genes and the ectopic expression of human genes or mutations in a tissue-specific manner; often resulting in Drosophila models which exhibit typical MND disease pathologies. These can then be further interrogated to identify disease-modifying genes or mutations and disease pathways. This review will discuss two common MNDs and the current Drosophila models which are being used to research their genetic basis and the different pathologies of MND."
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