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."

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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.

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."

Domain-sensory processing approach--new fly model for study of genetic basis of autism

Vilidaite G, Norcia AM, West RJH, Elliott CJH, Pei F, Wade AR, Baker DH. Autism sensory dysfunction in an evolutionarily conserved system. Proc Biol Sci. 2018 Dec 19;285(1893):20182255. PMID: 30963913.

Abstract: "There is increasing evidence for a strong genetic basis for autism, with many genetic models being developed in an attempt to replicate autistic symptoms in animals. However, current animal behaviour paradigms rarely match the social and cognitive behaviours exhibited by autistic individuals. Here, we instead assay another functional domain-sensory processing-known to be affected in autism to test a novel genetic autism model in Drosophila melanogaster. We show similar visual response alterations and a similar development trajectory in Nhe3 mutant flies (total n = 72) and in autistic human participants (total n = 154). We report a dissociation between first- and second-order electrophysiological visual responses to steady-state stimulation in adult mutant fruit flies that is strikingly similar to the response pattern in human adults with ASD as well as that of a large sample of neurotypical individuals with high numbers of autistic traits. We explain this as a genetically driven, selective signalling alteration in transient visual dynamics. In contrast to adults, autistic children show a decrease in the first-order response that is matched by the fruit fly model, suggesting that a compensatory change in processing occurs during development. Our results provide the first animal model of autism comprising a differential developmental phenotype in visual processing."

Fly study suggests link between bisphenol A (BPA), found in some plastics, and ADHD and autism

The results suggest BPA is a risk factor for the behavioral impairments that are the basis of autism and ADHD https://t.co/xzhUxws8ql

— Thomas Brody (@interactivefly) February 15, 2016

Review of Drosophila a model for neuropsychopharmacology-related research

Narayanan AS, Rothenfluh A. I Believe I Can Fly!: Use of Drosophila as a Model Organism in Neuropsychopharmacology Research. Neuropsychopharmacology. 2015 Oct 30. PMID: 26576740.

From the abstract:  "... Here, we outline why we study an invertebrate organism in the context of neuropsychiatric disorders, and we discuss how we can gain insight from studies in Drosophila. ... Highlighting some translational examples, we underline the fact that their brains works more like ours than one would have anticipated."

Their Fig. 1 provides a nice graphical summary of translational approaches.

Link between Hh and zinc revealed in flies could have relevance to several human diseases

Xie J, Owen T, Xia K, Singh AV, Tou E, Li L, Arduini B, Li H, Wan LQ, Callahan B, Wang C. Zinc inhibits Hedgehog autoprocessing: linking zinc deficiency with Hedgehog activation. J Biol Chem. 2015 May 1;290(18):11591-600. PMID: 25787080; PMCID: PMC4416862.

From the abstract:  "Zinc is an essential trace element with wide-ranging biological functions, whereas the Hedgehog (Hh) signaling pathway plays crucial roles in both development and disease. Here we show that there is a mechanistic link between zinc and Hh signaling. ... In normal physiology, zinc likely acts as a negative regulator of Hh autoprocessing and inhibits the generation of Hh ligand and Hh signaling. In many diseases, zinc deficiency and elevated level of Hh ligand co-exist, including prostate cancer, lung cancer, ovarian cancer, and autism. Our data suggest a causal relationship between zinc deficiency and the overproduction of Hh ligand."

Review looks at contributions of Drosophila research related to Fragile X syndrome and discusses discordance

Weisz ED, Monyak RE, Jongens TA. Deciphering Discord: How Drosophila research has enhanced our understanding of the importance of FMRP in different spatial and temporal contexts. Exp Neurol. 2015 May 27. pii: S0014-4886(15)30001-7. PMID: 26026973.

From the abstract: "Fragile X Syndrome (FXS) is the most common heritable form of intellectual impairment as well as the leading monogenetic cause of autism. ... Research efforts in Drosophila melanogaster have revealed key insights into the mechanistic underpinnings of FXS. While much remains unknown, it is increasingly apparent that FXS involves a myriad of spatial and temporally specific alterations in cellular function. Consequently, the literature is filled with numerous discordant findings. Researchers and clinicians alike must be cognizant of this dissonance, as it will likely be important for the design of preclinical studies to assess the efficacy of therapeutic strategies to improve the lives of FXS patients."

Drosophila study contributes to understanding of autism spectrum disorders-associated gene variants

Grice SJ, Liu JL, Webber C. Synergistic Interactions between Drosophila Orthologues of Genes Spanned by De Novo Human CNVs Support Multiple-Hit Models of Autism. PLoS Genet. 2015 Mar 27;11(3):e1004998. PMID: 25816101.

Fig. 1 from Grice et al. 2015 PLoS Genet.

From the abstract: "Autism spectrum disorders (ASDs) are highly heritable ... Although a number of highly penetrant ASD gene variants have been identified, there is growing evidence to support a causal role for combinatorial effects arising from the contributions of multiple loci. By examining synaptic and circadian neurological phenotypes resulting from the dosage variants of unique human:fly orthologues in Drosophila, we observe numerous synergistic interactions between pairs of informatically-identified candidate genes whose orthologues are jointly affected by large de novo copy number variants (CNVs). ... We first demonstrate that dosage alterations of the unique Drosophila orthologues of candidate genes from de novo CNVs that harbour only a single candidate gene display neurological defects similar to those previously reported in Drosophila models of ASD-associated variants. We then considered pairwise dosage changes within the set of orthologues of candidate genes that were affected by the same single human de novo CNV. ... Our study illustrates mechanisms through which synergistic effects resulting from large structural variation can contribute to human disease."

Review--flies, chromatin remodeling, and intellectual disability & neural disorders

Taniguchi H, Moore AW. Chromatin regulators in neurodevelopment and disease: Analysis of fly neural circuits provides insights: Networks of chromatin regulators and transcription factors underlie Drosophila neurogenesis and cognitive defects in intellectual disability and neuropsychiatric disorder models. Bioessays. 2014 Jul 28. PMID: 25067789.

At least the following disabilities, disorders or syndromes are mentioned in the review (Blogger does not allow tagging the entry with so many characters):  Intellectual disability, Schizophrenia, Autism, CHARGE syndrome, Coffin-Siris syndrome, Kabuki syndrome, Kleefstra syndrome, Maat-Kievit-Brunner syndrome, Nicolaides-Baraitser syndrome, Rubinstein-Taybi syndrome, Say-Barber-Biesecker-Young-Simpson syndrome, Schinzel-Giedion syndrome, Sotos syndrome, Weaver syndrome, Wiedemann-Steiner syndrome

Reveiw--model systems in the study of autism spectrum disorders

Doll CA, Broadie K. Impaired activity-dependent neural circuit assembly and refinement in autism spectrum disorder genetic models. Front Cell Neurosci. 2014 Feb 7;8:30. eCollection 2014. Review. PMID: 24570656; PMCID: PMC3916725.

Hyperlocomotion in flies expressing mutant form of hDAT associated with autism.

Hamilton PJ, Campbell NG, Sharma S, Erreger K, Herborg Hansen F, Saunders C, Belovich AN; NIH ARRA Autism Sequencing Consortium, Sahai MA, Cook EH, Gether U, McHaourab HS, Matthies HJ, Sutcliffe JS, Galli A. De novo mutation in the dopamine transporter gene associates dopamine dysfunction with autism spectrum disorder. Mol Psychiatry. 2013 Dec;18(12):1315-1323. PMID: 23979605.

From the abstract: "De novo genetic variation is an important class of risk factors for autism spectrum disorder (ASD). Recently, whole-exome sequencing of ASD families has identified a novel de novo missense mutation in the human dopamine (DA) transporter (hDAT) gene, which results in a Thr to Met substitution at site 356 (hDAT T356M). ... In Drosophila melanogaster, the expression of hDAT T356M in DA neurons-lacking Drosophila DAT leads to hyperlocomotion, a trait associated with DA dysfunction and ASD."

Accompanying image: Hamilton PJ, Campbell NG, Sharma S, Erreger K, Hansen FH, Saunders C, Belovich AN, Sahai MA, Cook EH, Gether U, McHaourab HS, Matthies HJ, Sutcliffe JS, Galli A. Drosophila melanogaster: a novel animal model for the behavioral characterization of autism-associated mutations in the dopamine transporter gene. Mol Psychiatry. 2013 Dec;18(12):1235. PMID: 24253181

Fly assays included in Fragile X study. Top3beta RNA topoisomerase. Recent report.

Xu D, Shen W, Guo R, Xue Y, Peng W, Sima J, Yang J, Sharov A, Srikantan S, Yang J, Fox D 3rd, Qian Y, Martindale JL, Piao Y, Machamer J, Joshi SR, Mohanty S, Shaw AC, Lloyd TE, Brown GW, Ko MS, Gorospe M, Zou S, Wang W. Top3β is an RNA topoisomerase that works with fragile X syndrome protein to promote synapse formation. Nat Neurosci. 2013 Sep;16(9):1238-47. PMID: 23912945.

Fly assay helps confirm relevance of ANK3 disruptions to neurodevelopmental disorders. Recent report.

Iqbal Z, Vandeweyer G, van der Voet M, Waryah AM, Zahoor MY, Besseling JA, Roca LT, Vulto-van Silfhout AT, Nijhof B, Kramer JM, Van der Aa N, Ansar M, Peeters H, Helsmoortel C, Gilissen C, Vissers LE, Veltman JA, de Brouwer AP, Frank Kooy R, Riazuddin S, Schenck A, van Bokhoven H, Rooms L. Homozygous and heterozygous disruptions of ANK3: at the crossroads of neurodevelopmental and psychiatric disorders. Hum Mol Genet. 2013 May 15;22(10):1960-70. PMID: 23390136.

From the abstract:  "... The causality of ANK3 mutations in the two families and the role of the gene in cognitive function were supported by memory defects in a Drosophila knockdown model. ...

New fly model: Autism spectrum disorders. Recent report.

Hahn N, Geurten B, Gurvich A, Piepenbrock D, Kästner A, Zanini D, Xing G, Xie W, Göpfert MC, Ehrenreich H, Heinrich R. Monogenic heritable autism gene neuroligin impacts Drosophila social behaviour. Behav Brain Res. 2013 Sep 1;252:450-7. PMID: 23792025.

From the abstract:  "... Drosophila can thus be used to study the contribution of Neuroligins to synaptic function, social interactions and their implication in ASDs. "

New approach for study of learning and memory in flies. Relevance to disease-related study. Recent report.

The authors indicate relevance to "neurological pathologies such as Parkinson's disease, Alzheimer's disease, addiction, epilepsy and autism spectrum disorders."

Mejia M, Heghinian MD, Marí F, Godenschwege TA. New Tools for Targeted Disruption of Cholinergic Synaptic Transmission in Drosophila melanogaster. PLoS One. 2013 May 30;8(5):e64685. PMID: 23737994; PMCID: PMC3667824.