Fly genetic study related to fatal infantile cardioencephalomyopathy, Leigh syndrome, and Charcot-Marie-Tooth disease,

Sci Rep. 2021 Oct 27;11(1):21207. doi: 10.1038/s41598-021-00663-2.

The function of Scox in glial cells is essential for locomotive ability in Drosophila.

Kowada R, Kodani A, Ida H, Yamaguchi M, Lee IS, Okada Y, Yoshida H

Abstract:

Synthesis of cytochrome c oxidase (Scox) is a Drosophila homolog of human SCO2 encoding a metallochaperone that transports copper to cytochrome c, and is an essential protein for the assembly of cytochrome c oxidase in the mitochondrial respiratory chain complex. SCO2 is highly conserved in a wide variety of species across prokaryotes and eukaryotes, and mutations in SCO2 are known to cause mitochondrial diseases such as fatal infantile cardioencephalomyopathy, Leigh syndrome, and Charcot-Marie-Tooth disease, a neurodegenerative disorder. These diseases have a common symptom of locomotive dysfunction. However, the mechanisms of their pathogenesis remain unknown, and no fundamental medications or therapies have been established for these diseases. In this study, we demonstrated that the glial cell-specific knockdown of Scox perturbs the mitochondrial morphology and function, and locomotive behavior in Drosophila. In addition, the morphology and function of synapses were impaired in the glial cell-specific Scox knockdown. Furthermore, Scox knockdown in ensheathing glia, one type of glial cell in Drosophila, resulted in larval and adult locomotive dysfunction. This study suggests that the impairment of Scox in glial cells in the Drosophila CNS mimics the pathological phenotypes observed by mutations in the SCO2 gene in humans.

DOI: 10.1038/s41598-021-00663-2
PMID: 34707123

Review: Info from hypoxia-tolerant species such as Drosophila could inform understanding of stroke

Int J Mol Sci. 2021 Oct 15;22(20):11131. doi: 10.3390/ijms222011131.

Hypoxia Tolerant Species: The Wisdom of Nature Translated into Targets for Stroke Therapy.

Del Río C, Montaner J

Abstract: Human neurons rapidly die after ischemia and current therapies for stroke management are limited to restoration of blood flow to prevent further brain damage. Thrombolytics and mechanical thrombectomy are the available reperfusion treatments, but most of the patients remain untreated. Neuroprotective therapies focused on treating the pathogenic cascade of the disease have widely failed. However, many animal species demonstrate that neurons can survive the lack of oxygen for extended periods of time. Here, we reviewed the physiological and molecular pathways inherent to tolerant species that have been described to contribute to hypoxia tolerance. Among them, Foxo3 and Eif5A were reported to mediate anoxic survival in Drosophila and Caenorhabditis elegans, respectively, and those results were confirmed in experimental models of stroke. In humans however, the multiple mechanisms involved in brain cell death after a stroke causes translation difficulties to arise making necessary a timely and coordinated control of the pathological changes. We propose here that, if we were able to plagiarize such natural hypoxia tolerance through drugs combined in a pharmacological cocktail it would open new therapeutic opportunities for stroke and likely, for other hypoxic conditions.

DOI: 10.3390/ijms222011131
PMCID: PMC8537001
PMID: 34681788

Drosophila assays of movement and mitochondria included in study of an autosomal dominant spastic paraplegia and dystonia

Mov Disord. 2021 Oct 11. doi: 10.1002/mds.28821

A Novel Variant of ATP5MC3 Associated with Both Dystonia and Spastic Paraplegia

Neilson DE, Zech M, Hufnagel RB, Slone J, Wang X, Homan S, Gutzwiller LM, Leslie EJ, Leslie ND, Xiao J, Hedera P, LeDoux MS, Gebelein B, Wilbert F, Eckenweiler M, Winkelmann J, Gilbert DL, Huang T

Abstract:

BACKGROUND: In a large pedigree with an unusual phenotype of spastic paraplegia or dystonia and autosomal dominant inheritance, linkage analysis previously mapped the disease to chromosome 2q24-2q31.

OBJECTIVE: The aim of this study is to identify the genetic cause and molecular basis of an unusual autosomal dominant spastic paraplegia and dystonia.

METHODS: Whole exome sequencing following linkage analysis was used to identify the genetic cause in a large family. Cosegregation analysis was also performed. An additional 384 individuals with spastic paraplegia or dystonia were screened for pathogenic sequence variants in the adenosine triphosphate (ATP) synthase membrane subunit C locus 3 gene (ATP5MC3). The identified variant was submitted to the "GeneMatcher" program for recruitment of additional subjects. Mitochondrial functions were analyzed in patient-derived fibroblast cell lines. Transgenic Drosophila carrying mutants were studied for movement behavior and mitochondrial function.

RESULTS: Exome analysis revealed a variant (c.318C > G; p.Asn106Lys) (NM_001689.4) in ATP5MC3 in a large family with autosomal dominant spastic paraplegia and dystonia that cosegregated with affected individuals. No variants were identified in an additional 384 individuals with spastic paraplegia or dystonia. GeneMatcher identified an individual with the same genetic change, acquired de novo, who manifested upper-limb dystonia. Patient fibroblast studies showed impaired complex V activity, ATP generation, and oxygen consumption. Drosophila carrying orthologous mutations also exhibited impaired mitochondrial function and displayed reduced mobility.

CONCLUSION: A unique form of familial spastic paraplegia and dystonia is associated with a heterozygous ATP5MC3 variant that also reduces mitochondrial complex V activity.

DOI: 10.1002/mds.28821
PMID: 34636445

Tumors sap nutrients from surrounding cells -- Drosophila study related to cancer

Dev Biol. 2021 Aug;476:294-307. doi: 10.1016/j.ydbio.2021.04.008

Autophagy induction in tumor surrounding cells promotes tumor growth in adult Drosophila intestines

Zhao H, Shi L, Kong R, Li Z, Liu F, Zhao H, Li Z

Abstract:

During tumorigenesis, tumor cells interact intimately with their surrounding cells (microenvironment) for their growth and progression. However, the roles of tumor microenvironment in tumor development and progression are not fully understood. Here, using an established benign tumor model in adult Drosophila intestines, we find that non-cell autonomous autophagy (NAA) is induced in tumor surrounding neighbor cells. Tumor growth can be significantly suppressed by genetic ablation of autophagy induction in tumor neighboring cells, indicating that tumor neighboring cells act as tumor microenvironment to promote tumor growth. Autophagy in tumor neighboring cells is induced downstream of elevated ROS and activated JNK signaling in tumor cells. Interestingly, we find that active transport of nutrients, such as amino acids, from tumor neighboring cells sustains tumor growth, and increasing nutrient availability could significantly restore tumor growth. Together, these data demonstrate that tumor cells take advantage of their surrounding normal neighbor cells as nutrient sources through NAA to meet their high metabolic demand for growth and progression. Thus we provide insights into our understanding of the mechanisms underlying the interaction between tumor cells and their microenvironment in tumor development.

DOI: 10.1016/j.ydbio.2021.04.008
PMID: 33940033

Drosophila used in study related to fragile X-associated primary ovariant insufficiency

Fertil Steril. 2021 Sep;116(3):843-854. doi: 10.1016/j.fertnstert.2021.04.021 

Identifying susceptibility genes for primary ovarian insufficiency on the high-risk genetic background of a fragile X premutation. 

Trevino CE, Rounds JC, Charen K, Shubeck L, Hipp HS, Spencer JB, Johnston HR, Cutler DJ, Zwick ME, Epstein MP, Murray A, Macpherson JN, Mila M, Rodriguez-Revenga L, Berry-Kravis E, Hall DA, Leehey MA, Liu Y, Welt C, Warren ST, Sherman SL. Jin P, Allen EG

Abstract:

OBJECTIVE: To identify modifying genes that explains the risk of fragile X-associated primary ovarian insufficiency (FXPOI).

DESIGN: Gene-based, case/control association study, followed by a functional screen of highly ranked genes using a Drosophila model.

SETTING: Participants were recruited from academic and clinical settings.

PATIENT(S): Women with a premutation (PM) who experienced FXPOI at the age of 35 years or younger (n = 63) and women with a PM who experienced menopause at the age of 50 years or older (n = 51) provided clinical information and a deoxyribonucleic acid sample for whole genome sequencing. The functional screen was on the basis of Drosophila TRiP lines.

INTERVENTION(S): Clinical information and a DNA sample were collected for whole genome sequencing.

MAIN OUTCOME MEASURES: A polygenic risk score derived from common variants associated with natural age at menopause was calculated and associated with the risk of FXPOI. Genes associated with the risk of FXPOI were identified on the basis of the P-value from gene-based association test and an altered level of fecundity when knocked down in the Drosophila PM model.

RESULTS: The polygenic risk score on the basis of common variants associated with natural age at menopause explained approximately 8% of the variance in the risk of FXPOI. Further, SUMO1 and KRR1 were identified as possible modifying genes associated with the risk of FXPOI on the basis of an untargeted gene analysis of rare variants.

CONCLUSIONS: In addition to the large genetic effect of a PM on ovarian function, the additive effects of common variants associated with natural age at menopause and the effect of rare modifying variants appear to play a role in FXPOI risk.

DOI: 10.1016/j.fertnstert.2021.04.021
PMID: 34016428

Review: Fly Models of Liver Diseases

Front Physiol. 2021 Sep 16;12:728407

Drosophila melanogaster: A Powerful Tiny Animal Model for the Study of Metabolic Hepatic Diseases

Moraes KCM, Montagne J

Animal experimentation is limited by unethical procedures, time-consuming protocols, and high cost. Thus, the development of innovative approaches for disease treatment based on alternative models in a fast, safe, and economic manner is an important, yet challenging goal. In this paradigm, the fruit-fly Drosophila melanogaster has become a powerful model for biomedical research, considering its short life cycle and low-cost maintenance. In addition, biological processes are conserved and homologs of ∼75% of human disease-related genes are found in the fruit-fly. Therefore, this model has been used in innovative approaches to evaluate and validate the functional activities of candidate molecules identified via in vitro large-scale analyses, as putative agents to treat or reverse pathological conditions. In this context, Drosophila offers a powerful alternative to investigate the molecular aspects of liver diseases, since no effective therapies are available for those pathologies. Non-alcoholic fatty liver disease is the most common form of chronic hepatic dysfunctions, which may progress to the development of chronic hepatitis and ultimately to cirrhosis, thereby increasing the risk for hepatocellular carcinoma (HCC). This deleterious situation reinforces the use of the Drosophila model to accelerate functional research aimed at deciphering the mechanisms that sustain the disease. In this short review, we illustrate the relevance of using the fruit-fly to address aspects of liver pathologies to contribute to the biomedical area.

DOI: 10.3389/fphys.2021.728407
PMCID: PMC8481879
PMID: 34603083

Drosophila study related to aging and age-related disorders

Proc Natl Acad Sci U S A. 2021 Oct 5;118(40):e2110387118.

A genetic model of methionine restriction extends Drosophila health- and
lifespan.

Parkhitko AA, Wang L, Filine E, Jouandin P, Leshchiner D, Binari R, Asara JM, Rabinowitz JD, Perrimon N

Loss of metabolic homeostasis is a hallmark of aging and is characterized by dramatic metabolic reprogramming. To analyze how the fate of labeled methionine is altered during aging, we applied 13C5-Methionine labeling to Drosophila and demonstrated significant changes in the activity of different branches of the methionine metabolism as flies age. We further tested whether targeted degradation of methionine metabolism components would "reset" methionine metabolism flux and extend the fly lifespan. Specifically, we created transgenic flies with inducible expression of Methioninase, a bacterial enzyme capable of degrading methionine and revealed methionine requirements for normal maintenance of lifespan. We also demonstrated that microbiota-derived methionine is an alternative and important source in addition to food-derived methionine. In this genetic model of methionine restriction (MetR), we also demonstrate that either whole-body or tissue-specific Methioninase expression can dramatically extend Drosophila health- and lifespan and exerts physiological effects associated with MetR. Interestingly, while previous dietary MetR extended lifespan in flies only in low amino acid conditions, MetR from Methioninase expression extends lifespan independently of amino acid levels in the food. Finally, because impairment of the methionine metabolism has been previously associated with the development of Alzheimer's disease, we compared methionine metabolism reprogramming between aging flies and a Drosophila model relevant to Alzheimer's disease, and found that overexpression of human Tau caused methionine metabolism flux reprogramming similar to the changes found in aged flies. Altogether, our study highlights Methioninase as a potential agent for health- and lifespan extension.

DOI: 10.1073/pnas.2110387118
PMID: 34588310

Drosophila assay developed to test variants of human PTEN, a gene associate with cancers and ASD

A scalable Drosophila assay for clinical interpretation of human PTEN variants in suppression of PI3K/AKT induced cellular proliferation

Payel Ganguly, Landiso Madonsela, Jesse T. Chao, Christopher J. R. Loewen, Timothy P. O’Connor, Esther M. Verheyen, Douglas W. Allan

Abstract: "Gene variant discovery is becoming routine, but it remains difficult to usefully interpret the functional consequence or disease relevance of most variants. ... Drosophila melanogaster offers great potential as an assay platform, but was untested for high numbers of human variants adherent to these guidelines. Here, we wished to test the utility of Drosophila as a platform for scalable well-established assays. We took a genetic interaction approach to test the function of ~100 human PTEN variants in cancer-relevant suppression of PI3K/AKT signaling in cellular growth and proliferation. We validated the assay using biochemically characterized PTEN mutants as well as 23 total known pathogenic and benign PTEN variants, all of which the assay correctly assigned into predicted functional categories. ... Overall, we demonstrate that Drosophila offers a powerful assay platform for clinical variant interpretation, that can be used in conjunction with other well-established assays, to increase confidence in the accurate assessment of variant function and pathogenicity."

Access a Science in Vancouver feature on this article here.

Genetic and drug screens applied to a Drosophila model of acute myeloid leukemia reveal potential link to hypoxia signaling

Dis Model Mech. 2021 Sep 28:dmm.048953. doi: 10.1242/dmm.048953.  

Pharmacological or genetic inhibition of hypoxia signaling attenuates oncogenic
RAS-induced cancer phenotypes.

Zhu JY, Huang X, Fu Y, Wang Y, Zheng P, Liu Y, Han Z

Author information:
(1)Center for Precision Disease Modeling, Department of Medicine, University of
Maryland School of Medicine, Baltimore, MD 21201, USA.
(2)Division of Endocrinology, Diabetes and Nutrition, Department of Medicine,
University of Maryland School of Medicine, Baltimore, MD 21201, USA.
(3)Division of Immunotherapy, University of Maryland School of Medicine,
Baltimore, MD 21201, USA.

Abstract: "Oncogenic Ras mutations are highly prevalent in hematopoietic malignancies. However, it is difficult to directly target oncogenic RAS proteins for therapeutic intervention. We have developed a Drosophila Acute Myeloid Leukemia (AML) model induced by human KRASG12V, which exhibits a dramatic increase in myeloid-like leukemia cells. We performed both genetic and drug screens using this model. The genetic screen identified 24 candidate genes able to attenuate the oncogenic RAS-induced phenotype, including two key hypoxia pathway genes HIF1A and ARNT (HIF1B). The drug screen revealed echinomycin, an inhibitor of HIF1A, could effectively attenuate the leukemia phenotype caused by KRASG12V. Furthermore, we showed that echinomycin treatment could effectively suppress oncogenic RAS-driven leukemia cell proliferation using both human leukemia cell lines and a mouse xenograft model. These data suggest that inhibiting the hypoxia pathway could be an effective treatment approach for oncogenic RAS-induced cancer phenotype, and that echinomycin is a promising targeted drug to attenuate oncogenic RAS-induced cancer phenotypes."

DOI: 10.1242/dmm.048953
PMID: 34580712

Identification of protein interactors with fly GOLPH3 points to potential targets for cancer and other therapeutics

Cells. 2021 Sep 6;10(9):2336. doi: 10.3390/cells10092336.

Identification of GOLPH3 Partners in Drosophila Unveils Potential Novel Roles in Tumorigenesis and Neural Disorders.

Sechi S, Karimpour-Ghahnavieh A, Frappaolo A, Di Francesco L, Piergentili R, Schininà E, D'Avino PP, Giansanti MG

Author information:
(1)Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di
Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185
Roma, Italy.
(2)Dipartimento di Scienze Biochimiche A. Rossi Fanelli, Sapienza Università di
Roma, Piazzale A. Moro 5, 00185 Roma, Italy.
(3)Department of Pathology, University of Cambridge, Tennis Court Road,
Cambridge CB2 1QP, UK.

Abstract: "Golgi phosphoprotein 3 (GOLPH3) is a highly conserved peripheral membrane protein localized to the Golgi apparatus and the cytosol. GOLPH3 binding to Golgi membranes depends on phosphatidylinositol 4-phosphate [PI(4)P] and regulates Golgi architecture and vesicle trafficking. GOLPH3 overexpression has been correlated with poor prognosis in several cancers, but the molecular mechanisms that link GOLPH3 to malignant transformation are poorly understood. We recently showed that PI(4)P-GOLPH3 couples membrane trafficking with contractile ring assembly during cytokinesis in dividing Drosophila spermatocytes. Here, we use affinity purification coupled with mass spectrometry (AP-MS) to identify the protein-protein interaction network (interactome) of Drosophila GOLPH3 in testes. Analysis of the GOLPH3 interactome revealed enrichment for proteins involved in vesicle-mediated trafficking, cell proliferation and cytoskeleton dynamics. In particular, we found that dGOLPH3 interacts with the Drosophila orthologs of Fragile X mental retardation protein and Ataxin-2, suggesting a potential role in the pathophysiology of disorders of the nervous system. Our findings suggest novel molecular targets associated with GOLPH3 that might be relevant for therapeutic intervention in cancers and other human diseases."

DOI: 10.3390/cells10092336
PMID: 34571985

Review: Drosophila accessory gland as a model organ for studies related to prostate cancer

Cells. 2021 Sep 10;10(9):2387. doi: 10.3390/cells10092387.

Drosophila Accessory Gland: A Complementary In Vivo Model to Bring New Insight  to Prostate Cancer.

Rambur A, Vialat M, Beaudoin C, Lours-Calet C, Lobaccaro JM, Baron S, Morel L, de Joussineau C

Author information:
(1)Rosalind and Morris Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Montréal, QC H3A 1A3, Canada.
(2)Institut de Génétique, Reproduction et Développement, Université Clermont Auvergne, CNRS UMR6293, INSERM U1103, 28 Place Henri Dunant, BP38, 63001 Clermont-Ferrand, France.

Abstract: "Prostate cancer is the most common cancer in aging men. ... there are still few effective treatments to cure its aggressive and metastatic stages. ... multiple research models, such as cell culture and mouse models, have been developed over the years and have improved our comprehension of the biology of the disease. Recently, a new model has been added with the use of the Drosophila accessory gland. ... this functional equivalent of the prostate represents a powerful, inexpensive, and rapid in vivo model to study epithelial carcinogenesis. The purpose of this review is to quickly overview the existing prostate cancer models, including their strengths and limitations. In particular, we discuss how the Drosophila accessory gland can be integrated as a convenient complementary model ..."

DOI: 10.3390/cells10092387
PMID: 34572036

Fly disease model of Limb-girdle muscular dystrophy D2 (LGMDDs)

Blázquez-Bernal Á, Fernandez-Costa JM, Bargiela A, Artero R. Inhibition of autophagy rescues muscle atrophy in a LGMDD2 Drosophila model. FASEB J. 2021 Oct;35(10):e21914. doi: 10.1096/fj.202100539RR. PMID: 34547132.

From the abstract: "Limb-girdle muscular dystrophy D2 (LGMDD2) is an ultrarare autosomal dominant myopathy caused by mutation of ... TNPO3 ... . ... Here we report the first animal model of the disease by expressing the human mutant TNPO3 gene in Drosophila musculature or motor neurons and concomitantly silencing the endogenous expression of the fly protein ortholog. A similar genotype expressing wildtype TNPO3 served as a control. Phenotypes characterization revealed that mutant TNPO3 expression targeted at muscles or motor neurons caused LGMDD2-like phenotypes such as muscle degeneration and atrophy, and reduced locomotor ability. ... Upregulated muscle autophagy observed in LGMDD2 patients was also confirmed in the fly model, in which the anti-autophagic drug chloroquine was able to rescue histologic and functional phenotypes. Overall, we provide a proof of concept of autophagy as a target to treat disease phenotypes and propose a neurogenic component to explain mutant TNPO3 pathogenicity in diseased muscles."

Multi-species study looks at potential treatment of Anthrax

ACS Infect Dis. 2021 Aug 13;7(8):2176-2191. doi: 10.1021/acsinfecdis.1c00190.

In Vivo Activity of Repurposed Amodiaquine as a Host-Targeting Therapy for the Treatment of Anthrax.

Martchenko Shilman M, Bartolo G, Alameh S, Peterson JW, Lawrence WS, Peel JE, Sivasubramani SK, Beasley DWC, Cote CK, Demons ST, Halasahoris SA, Miller LL, Klimko CP, Shoe JL, Fetterer
DP, McComb R, Ho CC, Bradley KA, Hartmann S, Cheng LW, Chugunova M, Kao CY, Tran JK, Derbedrossian A, Zilbermintz L, Amali-Adekwu E, Levitin A, West J

Anthrax is caused by Bacillus anthracis and can result in nearly 100% mortality due in part to anthrax toxin. Antimalarial amodiaquine (AQ) acts as a host-oriented inhibitor of anthrax toxin endocytosis. Here, we determined the pharmacokinetics and safety of AQ in mice, rabbits, and humans as well as the efficacy in the fly, mouse, and rabbit models of anthrax infection. In the therapeutic-intervention studies, AQ nearly doubled the survival of mice infected subcutaneously with a B. anthracis dose lethal to 60% of the animals (LD60). In rabbits challenged with 200 LD50 of aerosolized B. anthracis, AQ as a monotherapy delayed death, doubled the survival rate of infected animals that received a suboptimal amount of antibacterial levofloxacin, and reduced bacteremia and toxemia in tissues. Surprisingly, the anthrax efficacy of AQ relies on an additional host macrophage-directed antibacterial mechanism, which was validated in the toxin-independent Drosophila model of Bacillus infection. Lastly, a systematic literature review of the safety and pharmacokinetics of AQ in humans from over 2 000 published articles revealed that AQ is likely safe when taken as prescribed, and its pharmacokinetics predicts anthrax efficacy in humans. Our results support the future examination of AQ as adjunctive therapy for the prophylactic anthrax treatment.

DOI: 10.1021/acsinfecdis.1c00190
PMCID: PMC8369491
PMID: 34218660 [Indexed for MEDLINE]

Conflict of interest statement: The authors declare the following competing financial interest(s): M.M.S. and L.Z. are co-inventors on the AQ patent for anthrax.

Multi-species study identifies inhibitory compound with potential use for Down Syndrome

Phytomedicine. 2021 Aug 1;92:153695. doi: 10.1016/j.phymed.2021.153695. Online
ahead of print.

Aristolactam BIII, a naturally derived DYRK1A inhibitor, rescues Down syndrome-related phenotypes.

Choi M, Kim AK, Ham Y, Lee JY, Kim D, Yang A, Jo MJ, Yoon E, Heo JN, Han SB, Ki MH, Lee KS, Cho S

BACKGROUND: Dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) is a significant pathogenic factor in Down syndrome (DS), wherein DYRK1A is overexpressed by 1.5-fold because of trisomy of human chromosome 21. Thus, DYRK1A inhibition is considered a therapeutic strategy to modify the disease.
PURPOSE: This study aims to identify a novel DYRK1A inhibitor and validate its therapeutic potential in DS-related pathological conditions.
 

STUDY DESIGN: In order to identify a novel DYRK1A inhibitor, we carried out two-step screening: a structure-based virtual screening of > 300,000 chemical library (first step) and cell-based nuclear factor of activated T-cells (NFAT)-response element (RE) promoter assay (second step). Primary hits were evaluated for their DYRK1A inhibitory activity using in vitro kinase assay and Tau phosphorylation in mammalian cells. Confirmed hit was further evaluated in pathological conditions including DYRK1A-overexpressing fibroblasts, flies, and mice.
 

RESULTS: We identified aristolactam BIII, a natural product derived from herbal plants, as a novel DYRK1A inhibitor. It potently inhibited the kinase activity of DYRK1A in vitro (IC50 = 9.67 nM) and effectively suppressed DYRK1A-mediated hyperphosphorylation of Tau in mammalian cells. Aristolactam BIII rescued the proliferative defects of DYRK1A transgenic (TG) mouse-derived fibroblasts and neurological and phenotypic defects of DS-like Drosophila models. Oral administration of aristolactam BIII acutely suppressed Tau hyperphosphorylation in the brain of DYRK1A TG mice. In the open field test, aristolactam BIII significantly ameliorated the exploratory behavioral deficit of DYRK1A TG mice.
 

CONCLUSION: Our work revealed that aristolactam BIII as a novel DYRK1A inhibitor rescues DS phenotypes in cells and in vivo and suggested its therapeutic potential for the treatment of DYRK1A-related diseases.

DOI: 10.1016/j.phymed.2021.153695
PMID: 34500300

New fly models with relevance to Multisystem Proteinopathy, ALS, and other valosin containig protein (VCP)-related diseases

"The power of a genetically tractable model organism coupled with well-established in vivo assays and a relatively short life cycle make Drosophila an attractive system to study VCP disease pathogenesis and novel treatment strategies."

Dis Model Mech. 2021 Jun 23:dmm.048603. doi: 10.1242/dmm.048603.

CRISPR/Cas9-engineered Drosophila knock-in models to study VCP diseases.

Wall JM, Basu A, Zunica ERM, Dubuisson OS, Pergola K, Broussard JP, Kirwan JP, Axelrod CL, Johnson AE

Abstract

"Valosin containing protein (VCP) is a hexameric type II AAA ATPase required for several cellular processes including ER-associated degradation, organelle biogenesis, autophagy and membrane fusion. VCP contains three domains: a regulatory N-terminal domain and two ATPase domains (D1 and D2). Mutations in the N-terminal and D1 domains are associated with several degenerative diseases, including Multisystem Proteinopathy (MSP-1) and ALS. However, patients with VCP mutations vary widely in their pathology and clinical penetrance, making it difficult to devise effective treatment strategies. Having a deeper understanding of how each mutation affects VCP function could enhance the prediction of clinical outcomes and design of personalized treatment options. Over-expressing VCP patient mutations in Drosophila has been shown to mimic many pathologies observed in human patients. The power of a genetically tractable model organism coupled with well-established in vivo assays and a relatively short life cycle make Drosophila an attractive system to study VCP disease pathogenesis and novel treatment strategies. Using CRISPR/Cas9, we have generated individual Drosophila knock-in mutants that include nine hereditary VCP disease mutations. We validate that these models display many hallmarks of VCP-mediated degeneration, including progressive decline in mobility, protein aggregate accumulation and defects in lysosomal and mitochondrial function. We also made some novel and unexpected findings, including laminopathies and sex-specific phenotypic differences in several mutants. Taken together, the Drosophila VCP disease models we have generated in this study will be useful for studying the etiology of individual VCP patient mutations and for testing potential genetic and/or pharmacological therapies."

DOI: 10.1242/dmm.048603
PMID: 34160014

Review article: "Discovering signaling mechanisms governing metabolism and metabolic diseases with Drosophila"

Cell Metab. 2021 Jun 11:S1550-4131(21)00269-2. doi: 10.1016/j.cmet.2021.05.018.

Discovering signaling mechanisms governing metabolism and metabolic diseases with Drosophila.

Kim SK, Tsao DD, Suh GSB, Miguel-Aliaga I]

Abstract:

There has been rapid growth in the use of Drosophila and other invertebrate systems to dissect mechanisms governing metabolism. New assays and approaches to physiology have aligned with superlative genetic tools in fruit flies to provide a powerful platform for posing new questions, or dissecting classical problems in metabolism and disease genetics. In multiple examples, these discoveries exploit experimental advantages as-yet unavailable in mammalian systems. Here, we illustrate how fly studies have addressed long-standing questions in three broad areas-inter-organ signaling through hormonal or neural mechanisms governing metabolism, intestinal interoception and feeding, and the cellular and signaling basis of sexually dimorphic metabolism and physiology-and how these findings relate to human (patho)physiology. The imaginative application of integrative physiology and related approaches in flies to questions in metabolism is expanding, and will be an engine of discovery, revealing paradigmatic features of metabolism underlying human diseases and physiological equipoise in health.

Copyright © 2021 Elsevier Inc. All rights reserved.

DOI: 10.1016/j.cmet.2021.05.018
PMID: 34139200

Review article: Fly research & COVID-19

"Remarkably, 90% of the SARS-CoV-2 virus-host interacting proteins are conserved between Drosophila and humans."

 

Cell Biosci. 2021 Jun 13;11(1):110. doi: 10.1186/s13578-021-00621-5.

Drosophila, a powerful model to study virus-host interactions and pathogenicity in the fight against SARS-CoV-2

van de Leemput J, Han Z

Abstract:

"The COVID-19 pandemic is having a tremendous impact on humanity. Although COVID-19 vaccines are showing promising results, they are not 100% effective and resistant mutant SARS-CoV-2 strains are on the rise. To successfully fight against SARS-CoV-2 and prepare for future coronavirus outbreaks, it is essential to understand SARS-CoV-2 protein functions, their host interactions, and how these processes convey pathogenicity at host tissue, organ and systemic levels. In vitro models are valuable but lack the physiological context of a whole organism. Current animal models for SARS-CoV-2 research are exclusively mammals, with the intrinsic limitations of long reproduction times, few progeny, ethical concerns and high maintenance costs. These limitations make them unsuitable for rapid functional investigations of virus proteins as well as genetic and pharmacological screens. Remarkably, 90% of the SARS-CoV-2 virus-host interacting proteins are conserved between Drosophila and humans. As a well-established model system for studying human diseases, the fruit fly offers a highly complementary alternative to current mammalian models for SARS-CoV-2 research, from investigating virus protein function to developing targeted drugs. Herein, we review Drosophila's track record in studying human viruses and discuss the advantages and limitations of using fruit flies for SARS-CoV-2 research. We also review studies that already used Drosophila to investigate SARS-CoV-2 protein pathogenicity and their damaging effects in COVID-19 relevant tissues, as well as studies in which the fly was used as an efficient whole animal drug testing platform for targeted therapeutics against SARS-CoV-2 proteins or their host interacting pathways."

DOI: 10.1186/s13578-021-00621-5
PMCID: PMC8200282
PMID: 34120640

Seminar Series: Model organisms in human disease research

Of interest to blog readers: 

In a Genes to Genomes blog post May 17, 2021, the Genetics Society of America has announced a new seminar series on "Advancing both basic science and medicine by studying human disease genes in model organisms." The series includes talks that will be presented in the summer and fall of 2021.

 View seminar topics and register to attend at this page.

Fly eye assay explored as a tool for assessing potential therapeutic treatments of chronic myeloid leukemia

Haematologica. 2020 Jan 31;105(2):387-397. doi: 10.3324/haematol.2019.219394. Print 2020.

Validation of a Drosophila model of wild-type and T315I mutated BCR-ABL1 in chronic myeloid leukemia: an effective platform for treatment screening.

Outa AA, Abubaker D, Bazarbachi A, Sabban ME, Shirinian M, Nasr R

Abstract:

Chronic myeloid leukemia is caused by a balanced chromosomal translocation resulting in the formation of BCR-ABL1 fusion gene encoding a constitutively active BCR-ABL1 tyrosine kinase, which activates multiple signal transduction pathways leading to malignant transformation. Standard treatment of chronic myeloid leukemia is based on tyrosine kinase inhibitors; however, some mutations have proven elusive particularly the T315I mutation. Drosophila melanogaster is an established in vivo model for human diseases including cancer. The targeted expression of chimeric human/fly and full human BCR-ABL1 in Drosophila eyes has been shown to result in detrimental effects. In this study, we expressed human BCR-ABL1p210 and the resistant BCR-ABL1p210/T315I fusion oncogenes in Drosophila eyes. Expression of BCR-ABL1p210/T315I resulted in a severe distortion of the ommatidial architecture of adult eyes with a more prominent rough eye phenotype compared to milder phenotypes in BCR-ABL1p210 reflecting a stronger oncogenic potential of the mutant. We then assessed the efficacy of the currently used tyrosine kinase inhibitors in BCR-ABL1p210 and BCR-ABL1p210/T315I expressing flies. Treatment of BCR-ABL1p210 expressing flies with potent kinase inhibitors (dasatinib and ponatinib) resulted in the rescue of ommatidial loss and the restoration of normal development. Taken together, we provide a chronic myeloid leukemia tailored BCR-ABL1p210 and BCR-ABL1p210/T315I fly model which can be used to test new compounds with improved therapeutic indices.

DOI: 10.3324/haematol.2019.219394
PMCID: PMC7012492
PMID: 31101753

Study exploring impact of phophorylation state of PINK1 includes rescue of PINK1 definiciency in Drosophila as investigative tool (relevance to Parkinsons Disease)

EMBO Rep. 2020 Aug 5;21(8):e48686. doi: 10.15252/embr.201948686. Epub 2020 Jun 2.

PINK1 phosphorylates Drp1(S616) to regulate mitophagy-independent mitochondrial dynamics.

Han H, Tan J, Wang R, Wan H, He Y, Yan X, Guo J, Gao Q, Li J, Shang S, Chen F, Tian R, Liu W,
Liao L, Tang B, Zhang Z

Abstract:

Impairment of PINK1/parkin-mediated mitophagy is currently proposed to be the molecular basis of mitochondrial abnormality in Parkinson's disease (PD). We here demonstrate that PINK1 directly phosphorylates Drp1 on S616. Drp1S616 phosphorylation is significantly reduced in cells and mouse tissues deficient for PINK1, but unaffected by parkin inactivation. PINK1-mediated mitochondrial fission is Drp1S616 phosphorylation dependent. Overexpression of either wild-type Drp1 or of the phosphomimetic mutant Drp1S616D, but not a dephosphorylation-mimic mutant Drp1S616A, rescues PINK1 deficiency-associated phenotypes in Drosophila. Moreover, Drp1 restores PINK1-dependent mitochondrial fission in ATG5-null cells and ATG7-null Drosophila. Reduced Drp1S616 phosphorylation is detected in fibroblasts derived from 4 PD patients harboring PINK1 mutations and in 4 out of 7 sporadic PD cases. Taken together, we have identified Drp1 as a substrate of PINK1 and a novel mechanism how PINK1 regulates mitochondrial fission independent of parkin and autophagy. Our results further link impaired PINK1-mediated Drp1S616 phosphorylation with the pathogenesis of both familial and sporadic PD.

DOI: 10.15252/embr.201948686
PMCID: PMC7403662
PMID: 32484300

Report relevant to age-related disorders tests effects of treatment with alpha-lipoic acid on Drosophila

EMBO Rep. 2020 Aug 5;21(8):e49583. doi: 10.15252/embr.201949583. Epub 2020 Jul 9.

Lipoic acid rejuvenates aged intestinal stem cells by preventing age-associated endosome reduction.

Du G, Qiao Y, Zhuo Z, Zhou J, Li X, Liu Z, Li Y, Chen H

Comment in
EMBO Rep. 2020 Aug 5;21(8):e51175.

Abstract:

The age-associated decline of adult stem cell function is closely related to the decline in tissue function and age-related diseases. However, the underlying mechanisms that ultimately lead to the observed functional decline of stem cells still remain largely unexplored. This study investigated Drosophila midguts and found a continuous downregulation of lipoic acid synthase, which encodes the key enzyme for the endogenous synthesis of alpha-lipoic acid (ALA), upon aging. Importantly, orally administration of ALA significantly reversed the age-associated hyperproliferation of intestinal stem cells (ISCs) and the
observed decline of intestinal function, thus extending the lifespan of Drosophila. This study reports that ALA reverses age-associated ISC dysfunction by promoting the activation of the endocytosis-autophagy network, which decreases in aged ISCs. Moreover, this study suggests that ALA may be used as a safe and effective anti-aging compound for the treatment of ISC-dysfunction-related diseases and for the promotion of healthy aging in humans.

DOI: 10.15252/embr.201949583
PMCID: PMC7403706
PMID: 32648369

Reports related to neurodegenerative diseases use Drosophila as a test system

Aging Cell. 2021 Apr 28:e13365. doi: 10.1111/acel.13365. Online ahead of print.

Vesicular glutamate transporter modulates sex differences in dopamine neuron
vulnerability to age-related neurodegeneration.

Buck SA, Steinkellner T, Aslanoglou D, Villeneuve M, Bhatte SH, Childers VC), Rubin SA, De Miranda BR, O'Leary EI, Neureiter EG, Fogle KJ, Palladino MJ, Logan RW, Glausier JR, Fish KN, Lewis DA(2), Greenamyre JT, McCabe BD, Cheetham CEJ, Hnasko TS, Freyberg Z

Age is the greatest risk factor for Parkinson's disease (PD) which causes progressive loss of dopamine (DA) neurons, with males at greater risk than females. Intriguingly, some DA neurons are more resilient to degeneration than others. Increasing evidence suggests that vesicular glutamate transporter (VGLUT) expression in DA neurons plays a role in this selective vulnerability. We investigated the role of DA neuron VGLUT in sex- and age-related differences in DA neuron vulnerability using the genetically tractable Drosophila model. We found sex differences in age-related DA neurodegeneration and its associated locomotor behavior, where males exhibit significantly greater decreases in both DA neuron number and locomotion during aging compared with females. We discovered that dynamic changes in DA neuron VGLUT expression mediate these age- and sex-related differences, as a potential compensatory mechanism for diminished DA neurotransmission during aging. Importantly, female Drosophila possess higher levels of VGLUT expression in DA neurons compared with males, and this finding is conserved across flies, rodents, and humans. Moreover, we showed that diminishing VGLUT expression in DA neurons eliminates females' greater resilience to DA neuron loss across aging. This offers a new mechanism for sex differences in selective DA neuron vulnerability to age-related DA neurodegeneration. Finally, in mice, we showed that the ability of DA neurons to achieve optimal control over VGLUT expression is essential for DA neuron survival. These findings lay the groundwork for the manipulation of DA neuron VGLUT expression as a novel therapeutic strategy to boost DA neuron resilience to age- and PD-related neurodegeneration.

DOI: 10.1111/acel.13365
PMID: 33909313

 

Cell Death Dis. 2020 Sep 10;11(9):739. doi: 10.1038/s41419-020-02942-8.

Enhanced accumulation of reduced glutathione by Scopoletin improves
survivability of dopaminergic neurons in Parkinson's model.

Pradhan P, Majhi O, Biswas A, Joshi VK, Sinha D

Parkinson's disease (PD) is a neuromotor disorder, primarily manifested by motor anomalies due to progressive loss of dopaminergic neurons. Although alterations in genetic factors have been linked with its etiology, exponential accumulation of environmental entities such as reactive oxygen species (ROS) initiate a cyclic chain reaction resulting in accumulation of cellular inclusions, dysfunctional mitochondria, and overwhelming of antioxidant machinery, thus accelerating disease pathogenesis. Involvement of oxidative stress in PD is further substantiated through ROS induced Parkinsonian models and elevated oxidative markers in clinical PD samples; thereby, making modulation of neuronal oxidative load as one of the major approaches in management of PD. Here we have found a potent antioxidant moiety Scopoletin (Sp), a common derivative in most of the nootropic herbs, with robust neuroprotective ability. Sp increased cellular resistance to ROS through efficient recycling of GSH to prevent oxidative damage. The Sp treated cells showed higher loads of reduced glutathione making them resistant to perturbation of antioxidant machinery or neurotoxin MPP+. Sp could restore the redox balance, mitochondrial function, and prevented oxidative damage, leading to recovery of dopaminergic neural networks and motion abilities in Drosophila genetic model of PD. Our data also suggest that Sp, in combination increases the therapeutic potency of L-DOPA by mitigating its chronic toxicity. Together, we highlight the possible ability of Sp in preventing oxidative stress mediated loss of dopaminergic neurons and at the same time enhance the efficacy of dopamine recharging regimens.

DOI: 10.1038/s41419-020-02942-8
PMCID: PMC7484898
PMID: 32913179

Drosophila used in study associating variants in UNC13B with epilepsy and/or febrile seizures

Brain. 2021 Apr 20:awab164. doi: 10.1093/brain/awab164. Online ahead of print.

UNC13B variants associated with partial epilepsy with favourable outcome.

Wang J(, Qiao JD, Liu XR, Liu DT, Chen YH, Wu Y, Sun Y, Yu J, Ren RN, Mei Z, Liu YX, Shi YW, Jiang M, Lin SM, He N, Li B, Bian WJ, Li BM(, Yi YH, Su T, Liu HK, Gu WY, Liao WP; China Epilepsy Gene 1.0 Project.

From the abstract:

"The unc-13 homolog B (UNC13B) gene encodes a presynaptic protein ... In this study we screened for novel genetic variants in a cohort of 446 unrelated cases (families) with partial epilepsy ... UNC13B variants were identified in 12 individuals affected by partial epilepsy and/or febrile seizures from eight unrelated families. ... The identified UNC13B variants included one nonsense variant, two variants at or around a splice site, one compound heterozygous missense variant, and four missense variants that cosegregated in the families. The frequency of UNC13B variants identified in the present study was significantly higher than that in a control cohort of Han Chinese and controls of the East Asian and all populations in the Genome Aggregation Database. Computational modeling, including hydrogen bond and docking analyses, suggested that the variants lead to functional impairment. In Drosophila, seizure rate and duration were increased by Unc13b knockdown compared to wild-type flies, but these effects were less pronounced than in sodium voltage-gated channel alpha subunit 1 (Scn1a) knockdown Drosophila. Electrophysiologic recordings showed that excitatory neurons in Unc13b-deficient flies exhibited increased excitability. These results suggest that UNC13B is potentially associated with epilepsy. ..."

DOI: 10.1093/brain/awab164
PMID: 33876820

Cross-species analysis related to Huntington's disease (fly, mouse, human)

Elife. 2021 Apr 19;10:e64564. doi: 10.7554/eLife.64564. Online ahead of print.

Downregulation of glial genes involved in synaptic function mitigates Huntington's Disease pathogenesis.

Onur TS, Laitman A, Zhao H, Keyho R, Kim H, Wang J, Mair M, Wang H, Li L, Perez A, de Haro M, Wan YW, Allen G, Lu B, Al-Ramahi I, Liu Z, Botas J

Abstract:

Most research on neurodegenerative diseases has focused on neurons, yet glia help form and maintain the synapses whose loss is so prominent in these conditions. To investigate the contributions of glia to Huntington's disease (HD), we profiled the gene expression alterations of Drosophila expressing human mutant Huntingtin (mHTT) in either glia or neurons and compared these changes to what is observed in HD human and HD mice striata. A large portion of conserved genes are concordantly dysregulated across the three species; we tested these genes in a high-throughput behavioral assay and found that downregulation of genes involved in synapse assembly mitigated pathogenesis and behavioral deficits. To our surprise, reducing dNRXN3 function in glia was sufficient to improve the phenotype of flies expressing mHTT in neurons, suggesting that mHTT's toxic effects in glia ramify throughout the brain. This supports a model in which dampening synaptic function is protective because it attenuates the  excitotoxicity that characterizes HD.

DOI: 10.7554/eLife.64564
PMID: 33871358

Comparison in Drosophila of 13 different human RASopathy isoforms points to differences in pathways affected and therapeutic responses

iScience. 2021 Mar 13;24(4):102306. doi: 10.1016/j.isci.2021.102306.

Drosophila RASopathy models identify disease subtype differences and biomarkers of drug efficacy.

Das TK, Gatto J, Mirmira R, Hourizadeh E, Kaufman D, Gelb BD, Cagan R

Abstract:

RASopathies represent a family of mostly autosomal dominant diseases that are caused by missense variants in the rat sarcoma viral oncogene/mitogen activated protein kinase (RAS/MAPK) pathway including KRAS, NRAS, BRAF, RAF1, and SHP2. These variants are associated with overlapping but distinct phenotypes that affect the heart, craniofacial, skeletal, lymphatic, and nervous systems. Here, we report an analysis of 13 Drosophila transgenic lines, each expressing a different human RASopathy isoform. Similar to their human counterparts, each Drosophila line displayed common aspects but also important differences including distinct signaling pathways such as the Hippo and SAPK/JNK signaling networks. We identified multiple classes of clinically relevant drugs-including statins and histone deacetylase inhibitors-that improved viability across most RASopathy lines; in contrast, several canonical RAS pathway inhibitors proved less broadly effective. Overall, our study compares and contrasts a large number of RASopathy-associated variants including their therapeutic responses.

DOI: 10.1016/j.isci.2021.102306
PMCID: PMC8026909
PMID: 33855281

Conflict of interest statement: B.G. declares royalties from GeneDx, Correlegan, LabCorp, and Prevention Genetics. B.G. is a named inventor on issued patents related to PTPN11, SHOC2, RAF1, and SOS1 mutations in Noonan syndrome. The Icahn School of Medicine at Mount Sinai licensed the patent to several diagnostics companies and has received royalty payments, some of which are distributed to B.G. B.G. and R.C. are principal investigators for a sponsored research agreement from Onconova.

Study looks at molecular mechsnisms underlying circadian rhythm disruption in fly model of Fragile X syndrome

Neurosci Bull. 2021 Apr 15. doi: 10.1007/s12264-021-00682-z.

Dysregulated CRMP Mediates Circadian Deficits in a Drosophila Model of Fragile X Syndrome.

Zhao J, Xue J, Zhu T, He H, Kang H, Jiang X, Huang W, Duan R

Abstract:

Fragile X syndrome (FXS) is the leading inherited cause of intellectual disability, resulting from the lack of functional fragile X mental retardation protein (FMRP), an mRNA binding protein mainly serving as a translational regulator. Loss of FMRP leads to dysregulation of target mRNAs. The Drosophila model of FXS show an abnormal circadian rhythm with disruption of the output pathway downstream of the clock network. Yet the FMRP targets involved in circadian regulation have not been identified. Here, we identified collapsing response mediator protein (CRMP) mRNA as a target of FMRP. Knockdown of pan-neuronal CRMP expression ameliorated the circadian defects and abnormal axonal structures of clock neurons (ventral lateral neurons) in dfmr1 mutant flies. Furthermore, specific reduction of CRMP in the downstream output insulin-producing cells attenuated the aberrant circadian behaviors. Molecular analyses revealed that FMRP binds with CRMP mRNA and negatively regulates its translation. Our results indicate that CRMP is an FMRP target and establish an essential role for CRMP in the circadian output in FXS Drosophila.

DOI: 10.1007/s12264-021-00682-z
PMID: 33856646

Light-activated receptors tested in Drosophila model of Parkinson's disease

PLoS Genet. 2021 Apr 15;17(4):e1009479. doi: 10.1371/journal.pgen.1009479.

Optogenetic delivery of trophic signals in a genetic model of Parkinson's disease.

Ingles-Prieto A, Furthmann N, Crossman SH Tichy AM, Hoyer N, Petersen M, Zheden V, Biebl J, Reichhart E, Gyoergy A, Siekhaus DE, Soba P, Winklhofer KF, Janovjak H

Abstract:

Optogenetics has been harnessed to shed new mechanistic light on current and future therapeutic strategies. This has been to date achieved by the regulation of ion flow and electrical signals in neuronal cells and neural circuits that are known to be affected by disease. In contrast, the optogenetic delivery of trophic biochemical signals, which support cell survival and are implicated in degenerative disorders, has never been demonstrated in an animal model of disease. Here, we reengineered the human and Drosophila melanogaster REarranged during Transfection (hRET and dRET) receptors to be activated by light, creating one-component optogenetic tools termed Opto-hRET and Opto-dRET. Upon blue light stimulation, these receptors robustly induced the MAPK/ERK proliferative signaling pathway in cultured cells. In PINK1B9 flies that exhibit loss of PTEN-induced putative kinase 1 (PINK1), a kinase associated with familial Parkinson's disease (PD), light activation of Opto-dRET suppressed mitochondrial defects, tissue degeneration and behavioral deficits. In human cells with PINK1 loss-of-function, mitochondrial fragmentation was rescued using Opto-dRET via the PI3K/NF-кB pathway. Our results demonstrate that a light-activated receptor can ameliorate disease hallmarks in a genetic model of PD. The optogenetic delivery of trophic signals is cell type-specific and reversible and thus has the potential to inspire novel strategies towards a spatio-temporal regulation of tissue repair.

DOI: 10.1371/journal.pgen.1009479
PMID: 33857132

Fly model related to FIG-4 associated neurological disorders uncovers potential link to epigenetic regulation

Neuroreport. 2021 May 5;32(7):562-568. doi: 10.1097/WNR.0000000000001636.

Identification of Rpd3 as a novel epigenetic regulator of Drosophila FIG 4, a
Charcot-Marie-Tooth disease-causing gene.

Muraoka Y, Nikaido A, Kowada R, Kimura H, Yamaguchi M, Yoshida H

Abstract:

Mutations in the factor-induced-gene 4 (FIG 4) gene are associated with multiple disorders, including Charcot-Marie-Tooth disease (CMT), epilepsy with polymicrogyria, Yunis-Varón syndrome and amyotrophic lateral sclerosis. The wide spectrum of disorders associated with FIG 4 may be related to the dysregulated epigenetics. Using Gene Expression Omnibus, we found that HDAC1 binds to the FIG 4 gene locus in the genome of human CD4+ T cells. Rpd3 is a well-known Drosophila homolog of human HDAC1. We previously established Drosophila models targeting Drosophila FIG 4 (dFIG 4) that exhibited defective locomotive ability, abnormal synapse morphology at neuromuscular junctions, enlarged vacuoles in the fat body and aberrant compound eye morphology. Genetic crossing experiments followed by physiological and immunocytochemical analyses revealed that Rpd3 mutations suppressed these defects induced by dFIG 4 knockdown. This demonstrated Rpd3 to be an important epigenetic regulator of dFIG 4, suggesting that the inhibition of HDAC1 represses the pathogenesis of FIG 4-associated disorders, including CMT. Defects in epigenetic regulators, such as HDAC1, may also explain the diverse symptoms of FIG 4-associated disorders.

Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.

DOI: 10.1097/WNR.0000000000001636
PMID: 33850086

Drosophila studies help in characterization of disease-associated variants in ATAD3A

Genome Med. 2021 Apr 12;13(1):55. doi: 10.1186/s13073-021-00873-3.

Functional interpretation of ATAD3A variants in neuro-mitochondrial phenotypes.

Yap ZY, Park YH, Wortmann SB, Gunning AC, Ezer S, Lee S, Duraine L, Wilichowski E, Wilson K, Mayr JA, Wagner M, Li H, Kini U, Black ED, Monaghan KG, Lupski JR, Ellard S, Westphal DS, Harel T, Yoon WH

From the abstract:

ATPase family AAA-domain containing protein 3A (ATAD3A) is a nuclear-encoded mitochondrial membrane-anchored protein involved in diverse processes including mitochondrial dynamics, mitochondrial DNA organization, and cholesterol metabolism. Biallelic deletions (null), recessive missense variants (hypomorph), and heterozygous missense variants or duplications (antimorph) in
ATAD3A lead to neurological syndromes in humans. ... To expand the mutational spectrum of ATAD3A variants and to provide functional interpretation of missense alleles in trans to deletion alleles, we
performed exome sequencing ... in ATAD3A in individuals with neurological and mitochondrial phenotypes. A Drosophila Atad3a Gal4 knockin-null allele was generated using CRISPR-Cas9 genome editing technology to aid the interpretation of variants. ... We report 13 individuals from 8 unrelated families with biallelic ATAD3A variants. ... Affected individuals exhibited findings previously associated with ATAD3A pathogenic variation ... Drosophila studies indicated that Phe50Leu, Gly236Val, Arg327Pro, and Lys568del are severe loss-of-function alleles ... Leu77Val and Arg170Trp
are partial loss-of-function alleles that cause progressive locomotion defects ... Our findings expand the allelic spectrum of ATAD3A variants and exemplify the use of a functional assay in Drosophila to aid variant interpretation.

DOI: 10.1186/s13073-021-00873-3
PMID: 33845882

Two models and the 'two-hit' model: Study in flies and Xenopus related to neurodevelopmental disorders

PLoS Genet. 2021 Apr 5;17(4):e1009112. doi: 10.1371/journal.pgen.1009112.

Functional assessment of the "two-hit" model for neurodevelopmental defects in Drosophila and X. laevis.

Pizzo L, Lasser M, Yusuff T, Jensen M, Ingraham P, Huber E, Singh MD, Monahan C, Iyer J, Desai I, Karthikeyan S, Gould DJ, Yennawar S, Weiner AT, Pounraja VK, Krishnan A, Rolls MM, Lowery LA, Girirajan S

Abstract:

We previously identified a deletion on chromosome 16p12.1 that is mostly inherited and associated with multiple neurodevelopmental outcomes, where severely affected probands carried an excess of rare pathogenic variants compared to mildly affected carrier parents. We hypothesized that the 16p12.1 deletion sensitizes the genome for disease, while "second-hits" in the genetic background modulate the phenotypic trajectory. To test this model, we examined how neurodevelopmental defects conferred by knockdown of individual 16p12.1 homologs are modulated by simultaneous knockdown of homologs of "second-hit" genes in Drosophila melanogaster and Xenopus laevis. We observed that knockdown of 16p12.1 homologs affect multiple phenotypic domains, leading to delayed developmental timing, seizure susceptibility, brain alterations, abnormal dendrite and axonal morphology, and cellular proliferation defects. Compared to genes within the 16p11.2 deletion, which has higher de novo occurrence, 16p12.1  homologs were less likely to interact with each other in Drosophila models or a human brain-specific interaction network, suggesting that interactions with "second-hit" genes may confer higher impact towards neurodevelopmental phenotypes. Assessment of 212 pairwise interactions in Drosophila between
16p12.1 homologs and 76 homologs of patient-specific "second-hit" genes (such as ARID1B and CACNA1A), genes within neurodevelopmental pathways (such as PTEN and UBE3A), and transcriptomic targets (such as DSCAM and TRRAP) identified genetic interactions in 63% of the tested pairs. In 11 out of 15 families, patient-specific "second-hits" enhanced or suppressed the phenotypic effects of one or many 16p12.1 homologs in 32/96 pairwise combinations tested. In fact, homologs of SETD5 synergistically interacted with homologs of MOSMO in both Drosophila and X. laevis, leading to modified cellular and brain phenotypes, as well as axon outgrowth defects that were not observed with knockdown of either individual homolog. Our results suggest that several 16p12.1 genes sensitize the  genome towards neurodevelopmental defects, and complex interactions with "second-hit" genes determine the ultimate phenotypic manifestation.

DOI: 10.1371/journal.pgen.1009112
PMID: 33819264

Review: Drosophila models of neurological diseases including ALS, CMT and Sotos syndrome

Exp Cell Res. 2021 Mar 31:112584. doi: 10.1016/j.yexcr.2021.112584. Online ahead
of print.

Drosophila models to study causative genes for human rare intractable
neurological diseases

Yamaguchi M, Lee IS, Jantrapirom S, Suda K, Yoshida H

Abstract

Drosophila is emerging as a convenient model for investigating human diseases. Functional homologues of almost 75% of human disease-related genes are found in Drosophila. Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease that causes defects in motoneurons. Charcot-Marie-Tooth disease (CMT) is one of the most commonly found inherited neuropathies affecting both motor and  sensory neurons. No effective therapy has been established for either of these diseases. In this review, after overviewing ALS, Drosophila models targeting several ALS-causing genes, including TDP-43, FUS and Ubiquilin2, are described with their genetic interactants. Then, after overviewing CMT, examples of
Drosophila models targeting several CMT-causing genes, including mitochondria-related genes and FIG 4, are also described with their genetic interactants. In addition, we introduce Sotos syndrome caused by mutations in the epigenetic regulator gene NSD1. Lastly, several genes and pathways that commonly interact with ALS- and/or CMT-causing genes are described. In the case of ALS and CMT that have many causative genes, it may be not practical to perform gene therapy for each of the many disease-causing genes. The possible uses of the common genes and pathways as novel diagnosis markers and effective  therapeutic targets are discussed.

Copyright © 2021. Published by Elsevier Inc.

DOI: 10.1016/j.yexcr.2021.112584
PMID: 33812867

Building bridges--new ModelMatcher resource

Readers of this blog are likely be interested to read this article appearing in Lab Animal and check out the new ModelMatcher online resource featured in the article. ModelMatcher was recently launched by Yamamoto and colleagues at Baylor College of Medicine. 

Are you a clinician interested to partner with labs that can harness the power of genetic model systems? Or an expert in Drosophila, C. elegans, or other models interested to partner with clinicians? 

Click to learn more! 

Lab Animal, "Model matchmaking" by Ellen P. Neff
ModelMatcher online resource

Additional resources of interest include:
DIOPT for ortholog mapping
MARRVEL for human disease variant exploration
BioLitMine for gene-centric literature search
Matchmaker Exchange
Monarch Initiative Explorer

Review article: "Investigating rare and ultrarare epilepsy syndromes with Drosophila models"

Fac Rev. 2021 Jan 29;10:10. doi: 10.12703/r/10-10. eCollection 2021.

Investigating rare and ultrarare epilepsy syndromes with Drosophila models.

Lasko P(1)(2), Lüthy K(1)(3).

Author information:
(1)Department of Human Genetics, Radboud University Medical Centre, Nijmegen,
Netherlands.
(2)Department of Biology, McGill University, Montréal, Québec, Canada.
(3)Donders Institute for Brain, Cognition and Behaviour, Radboud University
Medical Centre, Nijmegen, Netherlands.

Abstract:

One in three epilepsy cases is drug resistant, and seizures often begin in  infancy, when they are life-threatening and when therapeutic options are highly limited. An important tool for prioritizing and validating genes associated with epileptic conditions, which is suitable for large-scale screening, is disease  modeling in Drosophila. Approximately two-thirds of disease genes are conserved in Drosophila, and gene-specific fly models exhibit behavioral changes that are  related to symptoms of epilepsy. Models are based on behavior readouts, seizure-like attacks and paralysis following stimulation, and neuronal,  cell-biological readouts that are in the majority based on changes in nerve cell activity or morphology. In this review, we focus on behavioral phenotypes. Importantly, Drosophila modeling is independent of, and complementary to, other approaches that are computational and based on systems analysis. The large  number of known epilepsy-associated gene variants indicates a need for efficient research strategies. We will discuss the status quo of epilepsy disease modelling in Drosophila and describe promising steps towards the development of new drugs to reduce seizure rates and alleviate other epileptic symptoms.

Copyright: © 2021 Lasko P et al.

DOI: 10.12703/r/10-10
PMCID: PMC7894260
PMID: 33659928

Drosophila research helps inform hypothesis regarding effects of macrophages on metabolism

Front Cell Dev Biol. 2021 Feb 15;9:629238. doi: 10.3389/fcell.2021.629238.
eCollection 2021.

Polarization of Macrophages in Insects: Opening Gates for Immuno-Metabolic
Research.

Bajgar A(1), Krejčová G(1), Doležal T(1).

Author information:
(1)Department of Molecular Biology and Genetics, University of South Bohemia,
Ceske Budejovice, Czechia.

From the abstract:

Insulin resistance and cachexia represent severe metabolic syndromes accompanying a variety of human pathological states, from life-threatening cancer and sepsis to chronic inflammatory states, such as obesity and autoimmune disorders. ... Current progress in insect immuno-metabolic research reveals that the induction of insulin resistance might represent an adaptive mechanism during the acute phase of bacterial infection. In Drosophila, insulin resistance is induced by signaling factors released by bactericidal macrophages as a reflection of their metabolic polarization toward aerobic glycolysis. Such metabolic adaptation enables them to combat the invading pathogens efficiently but also makes them highly nutritionally demanding. Therefore, systemic metabolism has to be adjusted upon macrophage activation ... We hypothesize that insulin resistance evoked by macrophage-derived signaling factors represents an adaptive mechanism for the mobilization of sources and their preferential delivery toward the activated immune system. We consider here the validity of the presented model for mammals and human medicine. ... Chronic insulin resistance is at the base of many human metabolically conditioned diseases such as non-alcoholic steatohepatitis, atherosclerosis, diabetes, and cachexia. Therefore, revealing the original biological relevance of cytokine-induced insulin resistance may help to develop a suitable strategy for treating these frequent diseases.

Copyright © 2021 Bajgar, Krejčová and Doležal.

DOI: 10.3389/fcell.2021.629238
PMCID: PMC7917182
PMID: 33659253

It takes a zoo: Use of Drosophila and other organisms in aging research (review article)

Cell Mol Life Sci. 2021 Feb;78(4):1275-1304. doi: 10.1007/s00018-020-03658-w.
Epub 2020 Oct 9.

Nontraditional systems in aging research: an update.

Mikuła-Pietrasik J(1), Pakuła M(2), Markowska M(2), Uruski P(2),
Szczepaniak-Chicheł L(2), Tykarski A(2), Książek K(3).

Author information:
(1)Department of Pathophysiology of Ageing and Civilization Diseases, Poznań
University of Medical Sciences, Długa 1/2 Str., 61-848, Poznań, Poland.
(2)Department of Hypertensiology, Poznań University of Medical Sciences, Długa
1/2 Str., 61-848, Poznań, Poland.
(3)Department of Pathophysiology of Ageing and Civilization Diseases, Poznań
University of Medical Sciences, Długa 1/2 Str., 61-848, Poznań, Poland.
kksiazek@ump.edu.pl.

Research on the evolutionary and mechanistic aspects of aging and longevity has  a reductionist nature, as the majority of knowledge originates from experiments on a relatively small number of systems and species. Good examples are the studies on the cellular, molecular, and genetic attributes of aging (senescence) that are primarily based on a narrow group of somatic cells, especially fibroblasts. Research on aging and/or longevity at the organismal level is dominated, in turn, by experiments on Drosophila melanogaster, worms (Caenorhabditis elegans), yeast (Saccharomyces cerevisiae), and higher organisms
such as mice and humans. Other systems of aging, though numerous, constitute the minority. In this review, we collected and discussed a plethora of up-to-date findings about studies of aging, longevity, and sometimes even immortality in several valuable but less frequently used systems, including bacteria (Caulobacter crescentus, Escherichia coli), invertebrates (Turritopsis dohrnii, Hydra sp., Arctica islandica), fishes (Nothobranchius sp., Greenland shark), reptiles (giant tortoise), mammals (blind mole rats, naked mole rats, bats, elephants, killer whale), and even 3D organoids, to prove that they offer biogerontologists as much as the more conventional tools. At the same time, the diversified knowledge gained owing to research on those species may help to reconsider aging from a broader perspective, which should translate into a better understanding of this tremendously complex and clearly system-specific  phenomenon.

DOI: 10.1007/s00018-020-03658-w
PMID: 33034696

Drosophila models of oculopharyngeal muscular dystrophy (OPMD) included in study seeking therapeutic strategies for treating prion diseases

Neurotherapeutics. 2021 Feb 2. doi: 10.1007/s13311-020-00992-6

Anti-prion Drugs Targeting the Protein Folding Activity of the Ribosome Reduce PABPN1 Aggregation

Bamia A, Sinane M, Naït-Saïdi R, Dhiab J, Keruzoré M, Nguyen PH, Bertho A, Soubigou F, Halliez S, Blondel M, Trollet C, Simonelig M, Friocourt G, Béringue V, Bihel F, Voisset C

From the abstract: Prion diseases are caused by the propagation of PrPSc, the pathological conformation of the PrPC prion protein ... and no therapeutic solution is currently available. We thus sought to identify new anti-prion molecules and found that flunarizine inhibited PrPSc propagation in cell culture and significantly prolonged survival of prion-infected mice. Using an in silico therapeutic repositioning approach based on similarities with flunarizine chemical structure, we tested azelastine, duloxetine, ebastine, loperamide and metixene and showed that they all have an anti-prion activity. ... Strikingly, some of these drugs were also able to alleviate phenotypes due to PABPN1 nuclear aggregation in cell and Drosophila models of oculopharyngeal muscular dystrophy (OPMD). These data emphasize the therapeutic potential of anti-PFAR drugs for neurodegenerative and neuromuscular proteinopathies.

DOI: 10.1007/s13311-020-00992-6
PMID: 33533011

Drosophila model of Freeman-Sheldon Syndrome points to possible molecular mechanism undlerying effects of the syndrome on muscles

Biophys J. 2021 Jan 29:S0006-3495(21)00075-8. doi: 10.1016/j.bpj.2020.12.033.

Prolonged Myosin Binding Increases Muscle Stiffness in Drosophila Models of Freeman-Sheldon Syndrome.

Bell KM, Huang A, Kronert WA, Bernstein SI, Swank DM

Abstract: Freeman-Sheldon Syndrome (FSS) is characterized by congenital contractures resulting from dominant point mutations in the embryonic isoform of muscle myosin. To investigate its disease mechanism, we used Drosophila models expressing FSS myosin mutations Y583S or T178I in their flight and jump muscles. We isolated these muscles from heterozygous mutant Drosophila and performed skinned fiber mechanics. The most striking mechanical alteration was an increase in active muscle stiffness. Y583S/+ and T178I/+ fibers' elastic moduli increased 70% and 77%, respectively. Increased stiffness contributed to decreased power generation, 49% and 66%, as a result of increased work absorbed during the lengthening portion of the contractile cycle. Slower muscle kinetics also contributed to the mutant phenotype, as shown by 17% and 32% decreases in optimal frequency for power generation, and 27% and 41% slower muscle apparent rate constant 2πb. Combined with previous measurements of slower in vitro actin motility, our results suggest a rate reduction of at least one strongly-bound cross-bridge cycle transition that increases the time myosin spends strongly bound to actin, ton. Increased ton was further supported by decreased ATP affinity and a 16% slowing of jump muscle relaxation rate in T178I heterozygotes. Impaired muscle function caused diminished flight and jump ability of Y583S/+ and T178I/+ Drosophila. Based on our results, assuming that our model system mimics human skeletal muscle, we propose that one mechanism driving FSS is elevated muscle stiffness arising from prolonged ton in developing muscle fibers.

DOI: 10.1016/j.bpj.2020.12.033
PMID: 33524372

Fly model leads to new model for cellular mechanisms underlying diseases associated with disruption of Valosin-Containing Proteins

Nat Commun. 2021 Jan 21;12(1):513. doi: 10.1038/s41467-020-20796-8.

SVIP is a molecular determinant of lysosomal dynamic stability, neurodegeneration and lifespan.

Johnson AE, Orr BO, Fetter RD, Moughamian AJ, Primeaux LA,
Geier EG, Yokoyama JS, Miller BL, Davis GW
 

From the abstract:

Missense mutations in Valosin-Containing Protein (VCP) are linked to diverse degenerative diseases including IBMPFD, amyotrophic lateral sclerosis (ALS), muscular dystrophy and Parkinson's disease. Here, we characterize a VCP-binding co-factor (SVIP) that specifically recruits VCP to lysosomes. ... We also establish multiple links between SVIP and VCP-dependent disease in our Drosophila model system. ... Finally, we identify a human SVIP mutation and confirm the pathogenicity of this mutation in our Drosophila model. We propose a model for VCP disease based on the differential, co-factor-dependent recruitment of VCP to intracellular organelles.

DOI: 10.1038/s41467-020-20796-8
PMID: 33479240

Wondering what's IBMPFD? Answer: Inclusion body myopathy with early-onset Paget disease and frontotemporal dementia.

Study of the fly embryo as a route to understanding cellular mechanisms of cancer

Mol Biol Cell. 2021 Jan 21:mbcE20100625. doi: 10.1091/mbc.E20-10-0625.
Molecular mechanisms underlying cellular effects of human MEK1 mutations.

Marmion RA(1), Yang L(1), Goyal Y(1)(2)(3), Jindal GA(1)(2)(4), Wetzel JL(1)(5),
Singh M(1)(5), Schüpbach T(6), Shvartsman SY(1)(2)(6)(7).

Abstract:

Terminal regions of Drosophila embryos are patterned by signaling through ERK, which is genetically deregulated in multiple human diseases. Quantitative studies of terminal patterning have been recently used to investigate gain-of-function variants of human MEK1, encoding the MEK kinase that directly activates ERK by dual phosphorylation. Unexpectedly, several mutations reduced ERK activation by extracellular signals, possibly through a negative feedback triggered by signal-independent activity of the mutant variants. Here we present experimental evidence supporting this model. Using a MEK variant that combines a mutation within the negative regulatory region with alanine substitutions in the activation loop, we prove that pathogenic variants indeed acquire signal-independent kinase activity. We also demonstrate that signal-dependent activation of these variants is independent of KSR, a conserved adaptor that is indispensable for activation of normal MEK. Finally, we show that attenuation of ERK activation by extracellular signals stems from transcriptional induction of Mkp3, a dual specificity phosphatase that deactivates ERK by dephosphorylation. These findings in the Drosophila embryo highlight its power for investigating diverse effects of human disease mutations.

DOI: 10.1091/mbc.E20-10-0625
PMID: 33476180

Study of Drosophila orthologs of human Cyotsolic 5'-Nucleotidase II genes, which have been implicated in neuropsychiatric disorders

Transl Psychiatry. 2021 Jan 18;11(1):55. doi: 10.1038/s41398-020-01149-x.

Investigating cytosolic 5'-nucleotidase II family genes as candidates for neuropsychiatric disorders in Drosophila

Singgih EL, van der Voet M, Schimmel-Naber M, Brinkmann EL, Schenck
A, Franke B

Abstract:
Cytosolic 5'-nucleotidases II (cNT5-II) are an evolutionary conserved family of 5'-nucleotidases that catalyze the intracellular hydrolysis of nucleotides. In humans, the family is encoded by five genes, namely NT5C2, NT5DC1, NT5DC2, NT5DC3, and NT5DC4. While very little is known about the role of these genes in the nervous system, several of them have been associated with neuropsychiatric disorders. Here, we tested whether manipulating neuronal expression of cNT5-II orthologues affects neuropsychiatric disorders-related phenotypes in the model organism Drosophila melanogaster. We investigated the brain expression of Drosophila orthologues of cNT5-II family (dNT5A-CG2277, dNT5B-CG32549, and dNT5C-CG1814) using quantitative real-time polymerase chain reaction (qRT-PCR). Using the UAS/Gal4 system, we also manipulated the expression of these genes specifically in neurons. The knockdown was subjected to neuropsychiatric disorder-relevant behavioral assays, namely light-off jump reflex habituation and locomotor activity, and sleep was measured. In addition, neuromuscular
junction synaptic morphology was assessed. We found that dNT5A, dNT5B, and dNT5C were all expressed in the brain. dNT5C was particularly enriched in the brain, especially at pharate and adult stages. Pan-neuronal knockdown of dNT5A and dNT5C showed impaired habituation learning. Knockdown of each of the genes also consistently led to mildly reduced activity and/or increased sleep. None of the knockdown models displayed significant alterations in synaptic morphology. In conclusion, in addition to genetic associations with psychiatric disorders in humans, altered expression of cNT5-II genes in the Drosophila nervous system plays a role in disease-relevant behaviors.

DOI: 10.1038/s41398-020-01149-x
PMID: 33462198

Genetic screen in flies aims to identify new targets for cancer treatment

Cancers (Basel). 2021 Jan 14;13(2):E293. doi: 10.3390/cancers13020293.

Genetic Screening for Potential New Targets in Chronic Myeloid Leukemia Based on
Drosophila Transgenic for Human BCR-ABL1.

Lo Iacono M(1), Signorino E(1), Petiti J(1), Pradotto M(1), Calabrese C(1),
Panuzzo C(1), Caciolli F(1), Pergolizzi B(1), De Gobbi M(1), Rege-Cambrin G(1),
Fava C(1), Giachino C(1), Bracco E(2), Saglio G(1), Frassoni F(1), Cilloni D(1).

Author information:
(1)Department of Clinical and Biological Sciences, University of Turin, 10043
Turin, Italy.
(2)Department of Oncology, University of Turin, 10043 Turin, Italy.

Chronic myeloid leukemia is a myeloproliferative neoplasm characterized by the presence of the Philadelphia chromosome that originates from the reciprocal translocation t(9;22)(q34;q11.2) and encodes for the constitutively active tyrosine kinase protein BCR-ABL1 from the Breakpoint Cluster Region (BCR) sequence and the Abelson (ABL1) gene. Despite BCR-ABL1 being one of the most studied oncogenic proteins, some molecular mechanisms remain enigmatic, and several of the proteins, acting either as positive or negative BCR-ABL1 regulators, are still unknown. The Drosophila melanogaster represents a powerful tool for genetic investigations and a promising model to study the BCR-ABL1 signaling pathway. To identify new components involved in BCR-ABL1 transforming activity, we conducted an extensive genetic screening using different Drosophila mutant strains carrying specific small deletions within the chromosomes 2 and 3 and the gmrGal4,UAS-BCR-ABL1 4M/TM3 transgenic Drosophila as the background. From the screening, we identified several putative candidate genes that may be involved either in sustaining chronic myeloid leukemia (CML) or in its progression. We also identified, for the first time, a tight connection between the BCR-ABL1 protein and Rab family members, and this correlation was also validated in CML patients. In conclusion, our data identified many genes that, by interacting with BCR-ABL1, regulate several important biological pathways and could promote disease onset and progression.

DOI: 10.3390/cancers13020293
PMID: 33466839

Preprint: ORF3a protein from the virus that causes COVID-19 is pathogenic in Drosophila

SARS-CoV-2 protein ORF3a is pathogenic in Drosophila and causes phenotypes associated with COVID-19 post-viral syndrome

Shuo Yang, Meijie Tian, Aaron N. Johnson 

Summary: The Coronavirus Disease 2019 (COVID-19) pandemic has caused millions of deaths and will continue to exact incalculable tolls worldwide. While great strides have been made toward understanding and combating the mechanisms of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection, relatively little is known about the individual SARS-CoV-2 proteins that contribute to pathogenicity during infection and that cause neurological sequela after viral clearance. We used Drosophila to develop an in vivo model that characterizes mechanisms of SARS-CoV-2 pathogenicity, and found ORF3a adversely affects longevity and motor function by inducing apoptosis and inflammation in the nervous system. Chloroquine alleviated ORF3a induced phenotypes in the CNS, arguing our Drosophila model is amenable to high throughput drug screening. Our work provides novel insights into the pathogenic nature of SARS-CoV-2 in the nervous system that can be used to develop new treatment strategies for post-viral syndrome.

https://www.biorxiv.org/content/10.1101/2020.12.20.423533v1

Preprint: Results of a Drosophila study of ASD-associated gene variants impacts understanding of neurological diseases

Drosophila functional screening of de novo variants in autism uncovers deleterious variants and facilitates discovery of rare neurodevelopmental diseases

Marcogliese et al.

BioRxiv pre-print:
https://www.biorxiv.org/content/10.1101/2020.12.30.424813v1

Abstract: Individuals with autism spectrum disorders (ASD) exhibit an increased burden of de novo variants in a broadening range of genes. We functionally tested the effects of ASD missense variants using Drosophila through ‘humanization’ rescue and overexpression-based strategies. We studied 79 ASD variants in 74 genes identified in the Simons Simplex Collection and found 38% of them caused functional alterations. Moreover, we identified GLRA2 as the cause of a spectrum of neurodevelopmental phenotypes beyond ASD in eight previously undiagnosed subjects. Functional characterization of variants in ASD candidate genes point to conserved neurobiological mechanisms and facilitates gene discovery for rare neurodevelopmental diseases.