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1.
Transl Psychiatry ; 11(1): 55, 2021 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-33462198

RESUMO

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.

2.
Am J Psychiatry ; 177(9): 855-866, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32600152

RESUMO

OBJECTIVE: Attention deficit hyperactivity disorder (ADHD) is a highly heritable psychiatric disorder. The objective of this study was to define ADHD-associated candidate genes and their associated molecular modules and biological themes, based on the analysis of rare genetic variants. METHODS: The authors combined data from 11 published copy number variation studies in 6,176 individuals with ADHD and 25,026 control subjects and prioritized genes by applying an integrative strategy based on criteria including recurrence in individuals with ADHD, absence in control subjects, complete coverage in copy number gains, and presence in the minimal region common to overlapping copy number variants (CNVs), as well as on protein-protein interactions and information from cross-species genotype-phenotype annotation. RESULTS: The authors localized 2,241 eligible genes in the 1,532 reported CNVs, of which they classified 432 as high-priority ADHD candidate genes. The high-priority ADHD candidate genes were significantly coexpressed in the brain. A network of 66 genes was supported by ADHD-relevant phenotypes in the cross-species database. Four significantly interconnected protein modules were found among the high-priority ADHD genes. A total of 26 genes were observed across all applied bioinformatic methods. Lookup in the latest genome-wide association study for ADHD showed that among those 26 genes, POLR3C and RBFOX1 were also supported by common genetic variants. CONCLUSIONS: Integration of a stringent filtering procedure in CNV studies with suitable bioinformatics approaches can identify ADHD candidate genes at increased levels of credibility. The authors' analytic pipeline provides additional insight into the molecular mechanisms underlying ADHD and allows prioritization of genes for functional validation in validated model organisms.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade , Encéfalo/metabolismo , Perfilação da Expressão Gênica/métodos , RNA Polimerase III , Fatores de Processamento de RNA , Transtorno do Deficit de Atenção com Hiperatividade/genética , Transtorno do Deficit de Atenção com Hiperatividade/metabolismo , Variações do Número de Cópias de DNA/fisiologia , Bases de Dados Genéticas , Estudos de Associação Genética/métodos , Predisposição Genética para Doença , Humanos , Mapeamento de Interação de Proteínas/métodos , RNA Polimerase III/genética , RNA Polimerase III/metabolismo , Fatores de Processamento de RNA/genética , Fatores de Processamento de RNA/metabolismo
4.
J Biol Chem ; 295(26): 8636-8646, 2020 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-32094227

RESUMO

O-GlcNAcylation is an abundant post-translational modification in neurons. In mice, an increase in O-GlcNAcylation leads to defects in hippocampal synaptic plasticity and learning. O-GlcNAcylation is established by two opposing enzymes: O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). To investigate the role of OGA in elementary learning, we generated catalytically inactive and precise knockout Oga alleles (OgaD133N and OgaKO , respectively) in Drosophila melanogaster Adult OgaD133N and OgaKO flies lacking O-GlcNAcase activity showed locomotor phenotypes. Importantly, both Oga lines exhibited deficits in habituation, an evolutionarily conserved form of learning, highlighting that the requirement for O-GlcNAcase activity for cognitive function is preserved across species. Loss of O-GlcNAcase affected a number of synaptic boutons at the axon terminals of larval neuromuscular junction. Taken together, we report behavioral and neurodevelopmental phenotypes associated with Oga alleles and show that Oga contributes to cognition and synaptic morphology in Drosophila.

5.
Am J Psychiatry ; 177(6): 526-536, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32046534

RESUMO

OBJECTIVE: Attention deficit hyperactivity disorder (ADHD) is a common, highly heritable neuropsychiatric disorder. ADHD often co-occurs with intellectual disability, and shared overlapping genetics have been suggested. The aim of this study was to identify novel ADHD genes by investigating whether genes carrying rare mutations linked to intellectual disability contribute to ADHD risk through common genetic variants. Validation and characterization of candidates were performed using Drosophila melanogaster. METHODS: Common genetic variants in a diagnostic gene panel of 396 autosomal intellectual disability genes were tested for association with ADHD risk through gene set and gene-wide analyses, using ADHD meta-analytic data from the Psychiatric Genomics Consortium for discovery (N=19,210) and ADHD data from the Lundbeck Foundation Initiative for Integrative Psychiatric Research for replication (N=37,076). The significant genes were functionally validated and characterized in Drosophila by assessing locomotor activity and sleep upon knockdown of those genes in brain circuits. RESULTS: The intellectual disability gene set was significantly associated with ADHD risk in the discovery and replication data sets. The three genes most consistently associated were MEF2C, ST3GAL3, and TRAPPC9. Performing functional characterization of the two evolutionarily conserved genes in Drosophila melanogaster, the authors found that their knockdown in dopaminergic (dMEF2) and circadian neurons (dTRAPPC9) resulted in increased locomotor activity and reduced sleep, concordant with the human phenotype. CONCLUSIONS: This study reveals that a large set of intellectual disability-related genes contribute to ADHD risk through effects of common alleles. Utilizing this continuity, the authors identified TRAPPC9, MEF2C, and ST3GAL3 as novel ADHD candidate genes. Characterization in Drosophila suggests that TRAPPC9 and MEF2C contribute to ADHD-related behavior through distinct neural substrates.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Locomoção/genética , Fatores de Regulação Miogênica/genética , Sialiltransferases/genética , Adulto , Idoso , Animais , Ritmo Circadiano , Neurônios Dopaminérgicos/metabolismo , Feminino , Técnicas de Silenciamento de Genes , Estudo de Associação Genômica Ampla , Humanos , Deficiência Intelectual/genética , Fatores de Transcrição MEF2/genética , Masculino , Pessoa de Meia-Idade , Neurônios/metabolismo , Sono/genética
6.
J Child Psychol Psychiatry ; 61(5): 545-555, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31849056

RESUMO

BACKGROUND: Mental disorders, including Attention-Deficit/Hyperactivity Disorder (ADHD), have a complex etiology, and identification of underlying genetic risk factors is challenging. This study used a multistep approach to identify and validate a novel risk gene for ADHD and psychiatric comorbidity. METHODS: In a single family, severely affected by ADHD and cooccurring disorders, we applied single nucleotide polymorphism (SNP)-array analysis to detect copy-number variations (CNVs) linked to disease. Genes present in the identified CNV were subsequently tested for their association with ADHD in the largest data set currently available (n = 55,374); this gene-set and gene-based association analyses were based on common genetic variants. Significant findings were taken forward for functional validation using Drosophila melanogaster as biological model system, altering gene expression using the GAL4-UAS system and a pan-neuronal driver, and subsequently characterizing locomotor activity and sleep as functional readouts. RESULTS: We identified a copy number gain in 8p23.3, which segregated with psychiatric phenotypes in the family and was confirmed by quantitative RT-PCR. Common genetic variants in this locus were associated with ADHD, especially those in FBXO25 and TDRP. Overexpression of the FBXO25 orthologue in two Drosophila models consistently led to increased locomotor activity and reduced sleep compared with the genetic background control. CONCLUSIONS: We combine ADHD risk gene identification in an individual family with genetic association testing in a large case-control data set and functional validation in a model system, together providing an important illustration of an integrative approach suggesting that FBXO25 contributes to key features of ADHD and comorbid neuropsychiatric disorders.

7.
Biol Psychiatry ; 86(4): 294-305, 2019 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-31272685

RESUMO

BACKGROUND: Although habituation is one of the most ancient and fundamental forms of learning, its regulators and its relevance for human disease are poorly understood. METHODS: We manipulated the orthologs of 286 genes implicated in intellectual disability (ID) with or without comorbid autism spectrum disorder (ASD) specifically in Drosophila neurons, and we tested these models in light-off jump habituation. We dissected neuronal substrates underlying the identified habituation deficits and integrated genotype-phenotype annotations, gene ontologies, and interaction networks to determine the clinical features and molecular processes that are associated with habituation deficits. RESULTS: We identified >100 genes required for habituation learning. For 93 of these genes, a role in habituation learning was previously unknown. These genes characterize ID disorders with macrocephaly and/or overgrowth and comorbid ASD. Moreover, individuals with ASD from the Simons Simplex Collection carrying damaging de novo mutations in these genes exhibit increased aberrant behaviors associated with inappropriate, stereotypic speech. At the molecular level, ID genes required for normal habituation are enriched in synaptic function and converge on Ras/mitogen-activated protein kinase (Ras/MAPK) signaling. Both increased Ras/MAPK signaling in gamma-aminobutyric acidergic (GABAergic) neurons and decreased Ras/MAPK signaling in cholinergic neurons specifically inhibit the adaptive habituation response. CONCLUSIONS: Our work supports the relevance of habituation learning to ASD, identifies an unprecedented number of novel habituation players, supports an emerging role for inhibitory neurons in habituation, and reveals an opposing, circuit-level-based mechanism for Ras/MAPK signaling. These findings establish habituation as a possible, widely applicable functional readout and target for pharmacologic intervention in ID/ASD.


Assuntos
Transtorno do Espectro Autista/genética , Comportamento Animal , Drosophila/fisiologia , Habituação Psicofisiológica/genética , Deficiência Intelectual/genética , Transdução de Sinais , Animais , Transtorno do Espectro Autista/diagnóstico , Modelos Animais de Doenças , Drosophila/genética , Humanos , Deficiência Intelectual/diagnóstico , Aprendizagem , Mutação , Fenótipo
8.
Dis Model Mech ; 12(5)2019 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-31088981

RESUMO

Intellectual disability (ID) and autism spectrum disorders (ASD) are frequently co-occurring neurodevelopmental disorders and affect 2-3% of the population. Rapid advances in exome and genome sequencing have increased the number of known implicated genes by threefold, to more than a thousand. The main challenges in the field are now to understand the various pathomechanisms associated with this bewildering number of genetic disorders, to identify new genes and to establish causality of variants in still-undiagnosed cases, and to work towards causal treatment options that so far are available only for a few metabolic conditions. To meet these challenges, the research community needs highly efficient model systems. With an increasing number of relevant assays and rapidly developing novel methodologies, the fruit fly Drosophila melanogaster is ideally positioned to change gear in ID and ASD research. The aim of this Review is to summarize some of the exciting work that already has drawn attention to Drosophila as a model for these disorders. We highlight well-established ID- and ASD-relevant fly phenotypes at the (sub)cellular, brain and behavioral levels, and discuss strategies of how this extraordinarily efficient and versatile model can contribute to 'next generation' medical genomics and to a better understanding of these disorders.


Assuntos
Transtorno do Espectro Autista/patologia , Drosophila melanogaster/fisiologia , Deficiência Intelectual/patologia , Animais , Transtorno do Espectro Autista/genética , Drosophila melanogaster/genética , Redes Reguladoras de Genes , Humanos , Deficiência Intelectual/genética , Pesquisa Médica Translacional
9.
Front Genet ; 10: 245, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30972103

RESUMO

Mitochondrial diseases are a group of rare life-threatening diseases often caused by defects in the oxidative phosphorylation system. No effective treatment is available for these disorders. Therapeutic development is hampered by the high heterogeneity in genetic, biochemical, and clinical spectra of mitochondrial diseases and by limited preclinical resources to screen and identify effective treatment candidates. Alternative models of the pathology are essential to better understand mitochondrial diseases and to accelerate the development of new therapeutics. The fruit fly Drosophila melanogaster is a cost- and time-efficient model that can recapitulate a wide range of phenotypes observed in patients suffering from mitochondrial disorders. We targeted three important subunits of complex I of the mitochondrial oxidative phosphorylation system with the flexible UAS-Gal4 system and RNA interference (RNAi): NDUFS4 (ND-18), NDUFS7 (ND-20), and NDUFV1 (ND-51). Using two ubiquitous driver lines at two temperatures, we established a collection of phenotypes relevant to complex I deficiencies. Our data offer models and phenotypes with different levels of severity that can be used for future therapeutic screenings. These include qualitative phenotypes that are amenable to high-throughput drug screening and quantitative phenotypes that require more resources but are likely to have increased potential and sensitivity to show modulation by drug treatment.

10.
PLoS Biol ; 17(3): e2006146, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30860988

RESUMO

Stress responses are crucial processes that require activation of genetic programs that protect from the stressor. Stress responses are also energy consuming and can thus be deleterious to the organism. The mechanisms coordinating energy consumption during stress response in multicellular organisms are not well understood. Here, we show that loss of the epigenetic regulator G9a in Drosophila causes a shift in the transcriptional and metabolic responses to oxidative stress (OS) that leads to decreased survival time upon feeding the xenobiotic paraquat. During OS exposure, G9a mutants show overactivation of stress response genes, rapid depletion of glycogen, and inability to access lipid energy stores. The OS survival deficiency of G9a mutants can be rescued by a high-sugar diet. Control flies also show improved OS survival when fed a high-sugar diet, suggesting that energy availability is generally a limiting factor for OS tolerance. Directly limiting access to glycogen stores by knocking down glycogen phosphorylase recapitulates the OS-induced survival defects of G9a mutants. We propose that G9a mutants are sensitive to stress because they experience a net reduction in available energy due to (1) rapid glycogen use, (2) an inability to access lipid energy stores, and (3) an overinduced transcriptional response to stress that further exacerbates energy demands. This suggests that G9a acts as a critical regulatory hub between the transcriptional and metabolic responses to OS. Our findings, together with recent studies that established a role for G9a in hypoxia resistance in cancer cell lines, suggest that G9a is of wide importance in controlling the cellular and organismal response to multiple types of stress.


Assuntos
Histona Metiltransferases/metabolismo , Animais , Antioxidantes/metabolismo , Metabolismo Energético/genética , Metabolismo Energético/fisiologia , Epigênese Genética/genética , Glicogênio Fosforilase/genética , Glicogênio Fosforilase/metabolismo , Histona Metiltransferases/genética , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Masculino , Estresse Oxidativo/genética , Estresse Oxidativo/fisiologia , Filogenia , Análise de Sequência de RNA
11.
Sci Rep ; 9(1): 2065, 2019 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-30765784

RESUMO

The fruit fly Drosophila melanogaster is a valuable model organism for the discovery and characterization of innate immune pathways, but host responses to virus infection remain incompletely understood. Here, we describe a novel player in host defense, Sgroppino (Sgp). Genetic depletion of Sgroppino causes hypersensitivity of adult flies to infections with the RNA viruses Drosophila C virus, cricket paralysis virus, and Flock House virus. Canonical antiviral immune pathways are functional in Sgroppino mutants, suggesting that Sgroppino exerts its activity via an as yet uncharacterized process. We demonstrate that Sgroppino localizes to peroxisomes, organelles involved in lipid metabolism. In accordance, Sgroppino-deficient flies show a defect in lipid metabolism, reflected by higher triglyceride levels, higher body mass, and thicker abdominal fat tissue. In addition, knock-down of Pex3, an essential peroxisome biogenesis factor, increases sensitivity to virus infection. Together, our results establish a genetic link between the peroxisomal protein Sgroppino, fat metabolism, and resistance to virus infection.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Metabolismo dos Lipídeos/genética , Peroxissomos/genética , Infecções por Vírus de RNA/genética , Vírus de RNA/patogenicidade , Animais , Dicistroviridae/patogenicidade , Drosophila melanogaster/virologia
12.
PLoS One ; 14(2): e0211652, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30753188

RESUMO

FOXP proteins form a subfamily of evolutionarily conserved transcription factors involved in the development and functioning of several tissues, including the central nervous system. In humans, mutations in FOXP1 and FOXP2 have been implicated in cognitive deficits including intellectual disability and speech disorders. Drosophila exhibits a single ortholog, called FoxP, but due to a lack of characterized mutants, our understanding of the gene remains poor. Here we show that the dimerization property required for mammalian FOXP function is conserved in Drosophila. In flies, FoxP is enriched in the adult brain, showing strong expression in ~1000 neurons of cholinergic, glutamatergic and GABAergic nature. We generate Drosophila loss-of-function mutants and UAS-FoxP transgenic lines for ectopic expression, and use them to characterize FoxP function in the nervous system. At the cellular level, we demonstrate that Drosophila FoxP is required in larvae for synaptic morphogenesis at axonal terminals of the neuromuscular junction and for dendrite development of dorsal multidendritic sensory neurons. In the developing brain, we find that FoxP plays important roles in α-lobe mushroom body formation. Finally, at a behavioral level, we show that Drosophila FoxP is important for locomotion, habituation learning and social space behavior of adult flies. Our work shows that Drosophila FoxP is important for regulating several neurodevelopmental processes and behaviors that are related to human disease or vertebrate disease model phenotypes. This suggests a high degree of functional conservation with vertebrate FOXP orthologues and established flies as a model system for understanding FOXP related pathologies.


Assuntos
Proteínas de Drosophila/fisiologia , Drosophila melanogaster/crescimento & desenvolvimento , Fatores de Transcrição Forkhead/fisiologia , Sistema Nervoso/crescimento & desenvolvimento , Animais , Animais Geneticamente Modificados , Comportamento Animal , Encéfalo/crescimento & desenvolvimento , Encéfalo/metabolismo , Sequência Conservada , Proteínas de Drosophila/genética , Drosophila melanogaster/metabolismo , Fatores de Transcrição Forkhead/genética , Técnicas de Silenciamento de Genes , Locomoção , Corpos Pedunculados/crescimento & desenvolvimento , Corpos Pedunculados/metabolismo , Sistema Nervoso/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Células Receptoras Sensoriais/fisiologia , Técnicas do Sistema de Duplo-Híbrido
13.
Psychiatr Genet ; 29(1): 1-17, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30376466

RESUMO

Animal and cellular models are essential tools for all areas of biological research including neuroscience. Model systems can also be used to investigate the pathophysiology of psychiatric disorders such as attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). In this review, we provide a summary of animal and cellular models for three genes linked to ADHD and ASD in human patients - CNTNAP2, ADGRL3, and PARK2. We also highlight the strengths and weaknesses of each model system. By bringing together behavioral and neurobiological data, we demonstrate how a cross-species approach can provide integrated insights into gene function and the pathogenesis of ADHD and ASD. The knowledge gained from transgenic models will be essential to discover and validate new treatment targets for these disorders.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Transtorno do Espectro Autista/fisiopatologia , Animais , Modelos Animais de Doenças , Drosophila , Humanos , Proteínas de Membrana/metabolismo , Camundongos , Modelos Biológicos , Proteínas do Tecido Nervoso/metabolismo , Receptores Acoplados a Proteínas-G/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Peixe-Zebra
14.
J Med Genet ; 56(5): 283-292, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30591515

RESUMO

BACKGROUND: Genetic forms of ataxia are a heterogenous group of degenerative diseases of the cerebellum. Many causative genes have been identified. We aimed to systematically investigate these genes to better understand ataxia pathophysiology. METHODS: A manually curated catalogue of 71 genes involved in disorders with progressive ataxias as a major clinical feature was subjected to an integrated gene ontology, protein network and brain gene expression profiling analysis. RESULTS: We found that genes mutated in ataxias operate in networks with significantly enriched protein connectivity, demonstrating coherence on a global level, independent of inheritance mode. Moreover, elevated expression specifically in the cerebellum predisposes to ataxia. Genes expressed in this pattern are significantly over-represented among genes mutated in ataxia and are enriched for ion homeostasis/synaptic functions. The majority of genes mutated in ataxia, however, does not show elevated cerebellar expression that could account for region-specific degeneration. For these, we identified defective cellular stress responses as a major common biological theme, suggesting that the defence pathways against stress are more critical to maintain cerebellar integrity than integrity of other brain regions. Approximately half of the genes mutated in ataxia, mostly part of the stress module, show higher expression at embryonic stages, which argues for a developmental predisposition. CONCLUSION: Genetic defects in ataxia predominantly affect neuronal homeostasis, to which the cerebellum appears to be excessively susceptible. Based on the identified modules, it is conceivable to propose common therapeutic interventions that target deregulated calcium and reactive oxygen species levels, or mechanisms that can decrease the harmful downstream effects of these deleterious insults.


Assuntos
Ataxia/etiologia , Encéfalo/metabolismo , Perfilação da Expressão Gênica , Modelos Biológicos , Ataxia/metabolismo , Ataxia/fisiopatologia , Ataxia Cerebelar/genética , Ataxia Cerebelar/metabolismo , Ataxia Cerebelar/fisiopatologia , Biologia Computacional/métodos , Bases de Dados Genéticas , Progressão da Doença , Suscetibilidade a Doenças , Regulação da Expressão Gênica , Ontologia Genética , Redes Reguladoras de Genes , Predisposição Genética para Doença , Humanos , Mapeamento de Interação de Proteínas , Mapas de Interação de Proteínas , Transcriptoma
15.
Am J Med Genet A ; 176(12): 2924-2929, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30302932

RESUMO

This report summarizes and highlights the fifth International RASopathies Symposium: When Development and Cancer Intersect, held in Orlando, Florida in July 2017. The RASopathies comprise a recognizable pattern of malformation syndromes that are caused by germ line mutations in genes that encode components of the RAS/mitogen-activated protein kinase (MAPK) pathway. Because of their common underlying pathogenetic etiology, there is significant overlap in their phenotypic features, which includes craniofacial dysmorphology, cardiac, cutaneous, musculoskeletal, gastrointestinal and ocular abnormalities, neurological and neurocognitive issues, and a predisposition to cancer. The RAS pathway is a well-known oncogenic pathway that is commonly found to be activated in somatic malignancies. As in somatic cancers, the RASopathies can be caused by various pathogenetic mechanisms that ultimately impact or alter the normal function and regulation of the MAPK pathway. As such, the RASopathies represent an excellent model of study to explore the intersection of the effects of dysregulation and its consequence in both development and oncogenesis.


Assuntos
Estudos de Associação Genética , Predisposição Genética para Doença , Proteínas ras/genética , Animais , Regulação da Expressão Gênica , Estudos de Associação Genética/métodos , Desenvolvimento Humano , Humanos , Modelos Biológicos , Terapia de Alvo Molecular , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Organogênese/genética , Transdução de Sinais , Síndrome , Proteínas ras/metabolismo
16.
Cell ; 175(3): 890-890.e1, 2018 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-30340048

RESUMO

Genetic ataxias are a clinically important group of disabling, mostly neurodegenerative, diseases of the cerebellum. This SnapShot shows that the vast majority of established monogenic causes of dominant and recessive ataxias can be captured by a limited number of affected cellular components and biological processes in the cerebellum. To view this SnapShot, open or download the PDF.


Assuntos
Ataxia Cerebelar/genética , Animais , Ataxia Cerebelar/metabolismo , Reparo do DNA , Humanos , Transporte de Íons , Células de Purkinje/metabolismo
17.
Brain ; 141(9): 2592-2604, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-30084953

RESUMO

Autosomal recessive cerebellar ataxias are a group of rare disorders that share progressive degeneration of the cerebellum and associated tracts as the main hallmark. Here, we report two unrelated patients with a new subtype of autosomal recessive cerebellar ataxia caused by biallelic, gene-disruptive mutations in GDAP2, a gene previously not implicated in disease. Both patients had onset of ataxia in the fourth decade. Other features included progressive spasticity and dementia. Neuropathological examination showed degenerative changes in the cerebellum, olive inferior, thalamus, substantia nigra, and pyramidal tracts, as well as tau pathology in the hippocampus and amygdala. To provide further evidence for a causative role of GDAP2 mutations in autosomal recessive cerebellar ataxia pathophysiology, its orthologous gene was investigated in the fruit fly Drosophila melanogaster. Ubiquitous knockdown of Drosophila Gdap2 resulted in shortened lifespan and motor behaviour anomalies such as righting defects, reduced and uncoordinated walking behaviour, and compromised flight. Gdap2 expression levels responded to stress treatments in control flies, and Gdap2 knockdown flies showed increased sensitivity to deleterious effects of stressors such as reactive oxygen species and nutrient deprivation. Thus, Gdap2 knockdown in Drosophila and GDAP2 loss-of-function mutations in humans lead to locomotor phenotypes, which may be mediated by altered responses to cellular stress.


Assuntos
Ataxia Cerebelar/genética , Ataxia Cerebelar/fisiopatologia , Proteínas do Tecido Nervoso/genética , Adulto , Animais , Ataxia/genética , Ataxia/fisiopatologia , Ataxia Cerebelar/metabolismo , Cerebelo/fisiologia , Proteínas de Drosophila/genética , Proteínas de Drosophila/fisiologia , Drosophila melanogaster/genética , Drosophila melanogaster/fisiologia , Feminino , Técnicas de Silenciamento de Genes/métodos , Genes Recessivos , Predisposição Genética para Doença/genética , Humanos , Pessoa de Meia-Idade , Mutação , Proteínas do Tecido Nervoso/fisiologia , Fenótipo , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia
18.
Dis Model Mech ; 11(3)2018 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-29590638

RESUMO

Mitochondrial diseases are associated with a wide variety of clinical symptoms and variable degrees of severity. Patients with such diseases generally have a poor prognosis and often an early fatal disease outcome. With an incidence of 1 in 5000 live births and no curative treatments available, relevant animal models to evaluate new therapeutic regimes for mitochondrial diseases are urgently needed. By knocking down ND-18, the unique Drosophila ortholog of NDUFS4, an accessory subunit of the NADH:ubiquinone oxidoreductase (Complex I), we developed and characterized several dNDUFS4 models that recapitulate key features of mitochondrial disease. Like in humans, the dNDUFS4 KD flies display severe feeding difficulties, an aspect of mitochondrial disorders that has so far been largely ignored in animal models. The impact of this finding, and an approach to overcome it, will be discussed in the context of interpreting disease model characterization and intervention studies.This article has an associated First Person interview with the first author of the paper.


Assuntos
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Comportamento Alimentar , Doenças Mitocondriais/metabolismo , Doenças Mitocondriais/patologia , Animais , Encéfalo/patologia , Encéfalo/fisiopatologia , Modelos Animais de Doenças , Corpo Adiposo/metabolismo , Técnicas de Silenciamento de Genes , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Doenças Mitocondriais/fisiopatologia , Atividade Motora , Músculos/metabolismo , Neurônios/metabolismo , Especificidade de Órgãos , Reprodutibilidade dos Testes
19.
J Vis Exp ; (129)2017 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-29155762

RESUMO

Advances in next-generation sequencing technologies contribute to the identification of (candidate) disease genes for movement disorders and other neurological diseases at an increasing speed. However, little is known about the molecular mechanisms that underlie these disorders. The genetic, molecular, and behavioral toolbox of Drosophila melanogaster makes this model organism particularly useful to characterize new disease genes and mechanisms in a high-throughput manner. Nevertheless, high-throughput screens require efficient and reliable assays that, ideally, are cost-effective and allow for the automatized quantification of traits relevant to these disorders. The island assay is a cost-effective and easily set-up method to evaluate Drosophila locomotor behavior. In this assay, flies are thrown onto a platform from a fixed height. This induces an innate motor response that enables the flies to escape from the platform within seconds. At present, quantitative analyses of filmed island assays are done manually, which is a laborious undertaking, particularly when performing large screens. This manuscript describes the "Drosophila Island Assay" and "Island Assay Analysis" algorithms for high-throughput, automated data processing and quantification of island assay data. In the setup, a simple webcam connected to a laptop collects an image series of the platform while the assay is performed. The "Drosophila Island Assay" algorithm developed for the open-source software Fiji processes these image series and quantifies, for each experimental condition, the number of flies on the platform over time. The "Island Assay Analysis" script, compatible with the free software R, was developed to automatically process the obtained data and to calculate whether treatments/genotypes are statistically different. This greatly improves the efficiency of the island assay and makes it a powerful readout for basic locomotion and flight behavior. It can thus be applied to large screens investigating fly locomotor ability, Drosophila models of movement disorders, and drug efficacy.


Assuntos
Drosophila/fisiologia , Ensaios de Triagem em Larga Escala/métodos , Locomoção/fisiologia , Animais , Comportamento Animal/fisiologia
20.
PLoS Genet ; 13(10): e1006864, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29069077

RESUMO

Kleefstra syndrome, caused by haploinsufficiency of euchromatin histone methyltransferase 1 (EHMT1), is characterized by intellectual disability (ID), autism spectrum disorder (ASD), characteristic facial dysmorphisms, and other variable clinical features. In addition to EHMT1 mutations, de novo variants were reported in four additional genes (MBD5, SMARCB1, NR1I3, and KMT2C), in single individuals with clinical characteristics overlapping Kleefstra syndrome. Here, we present a novel cohort of five patients with de novo loss of function mutations affecting the histone methyltransferase KMT2C. Our clinical data delineates the KMT2C phenotypic spectrum and reinforces the phenotypic overlap with Kleefstra syndrome and other related ID disorders. To elucidate the common molecular basis of the neuropathology associated with mutations in KMT2C and EHMT1, we characterized the role of the Drosophila KMT2C ortholog, trithorax related (trr), in the nervous system. Similar to the Drosophila EHMT1 ortholog, G9a, trr is required in the mushroom body for short term memory. Trr ChIP-seq identified 3371 binding sites, mainly in the promoter of genes involved in neuronal processes. Transcriptional profiling of pan-neuronal trr knockdown and G9a null mutant fly heads identified 613 and 1123 misregulated genes, respectively. These gene sets show a significant overlap and are associated with nearly identical gene ontology enrichments. The majority of the observed biological convergence is derived from predicted indirect target genes. However, trr and G9a also have common direct targets, including the Drosophila ortholog of Arc (Arc1), a key regulator of synaptic plasticity. Our data highlight the clinical and molecular convergence between the KMT2 and EHMT protein families, which may contribute to a molecular network underlying a larger group of ID/ASD-related disorders.


Assuntos
Transtorno do Espectro Autista/genética , Anormalidades Craniofaciais/genética , Proteínas do Citoesqueleto/genética , Proteínas de Ligação a DNA/genética , Proteínas de Drosophila/genética , Cardiopatias Congênitas/genética , Histona-Lisina N-Metiltransferase/genética , Deficiência Intelectual/genética , Proteínas do Tecido Nervoso/genética , Adolescente , Adulto , Animais , Transtorno do Espectro Autista/fisiopatologia , Sítios de Ligação/genética , Criança , Deleção Cromossômica , Cromossomos Humanos Par 9/genética , Anormalidades Craniofaciais/fisiopatologia , Drosophila melanogaster/genética , Feminino , Regulação da Expressão Gênica , Haploinsuficiência , Cardiopatias Congênitas/fisiopatologia , Histonas/genética , Humanos , Deficiência Intelectual/fisiopatologia , Masculino , Mutação , Plasticidade Neuronal/genética , Regiões Promotoras Genéticas
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