Project description:Neurodevelopmental disorders (NDDs) are heterogeneous conditions due to alterations of a variety of molecular mechanisms and cell dysfunctions. Epigenetic basis of NDDs have been reported in an increasingly number of cases while mitochondrial dysfunctions are more common within NDD patients than in the general population. Here, we investigated experimental models of Setd5 haploinsufficiency, that leads to NDDs in humans due to chromatin defects, and uncovered that mitochondrial dysfunction participates in the pathogenesis. Mitochondrial impairment is facilitated by transcriptional aberrations that follow the decrease of SETD5 enzyme. Low levels of SETD5 resulted in fragmented mitochondria, less mitochondrial potential and ATP production both in neural precursors and neurons. Mitochondria were miss-localized in mutant neurons, with few organelles within neurites and synapses. Our study explores the epigenetics/mitochondria interplay as an important aspect of NDD pathophysiology and defines the impairments of mitochondrial functionality and dynamics as new therapeutic targets for disorders associated with loss of SETD5.
Project description:SETD5, a gene linked to intellectual disability (ID) and autism spectrum disorder (ASD), is a member of the SET-domain family and encodes a putative histone methyltransferase (HMT). To date, the mechanism by which SETD5 haploinsufficiency causes ASD/ID remains an unanswered question. Setd5 is the highly conserved mouse homolog, and although the Setd5 null mouse is embryonic lethal, the heterozygote is viable. Morphological tracing and multi electrode array was used on cultured cortical neurons. MRI was conducted of adult mouse brains and immunohistochemistry of juvenile mouse brains. RNA-Seq was used to investigate gene expression in the developing cortex. Behavioral assays were conducted on adult mice. Setd5+/- cortical neurons displayed significantly reduced synaptic density and neuritic outgrowth in vitro, with corresponding decreases in network activity and synchrony by electrophysiology. A specific subpopulation of fetal Setd5+/- cortical neurons showed altered gene expression of neurodevelopment-related genes. Setd5+/- animals manifested several autism-like behaviors, including hyperactivity, cognitive deficit, and altered social interactions. Anatomical differences were observed in Setd5+/- adult brains, accompanied by a deficit of deep-layer cortical neurons in the developing brain. Our data converge on a picture of abnormal neurodevelopment driven by Setd5 haploinsufficiency, consistent with a highly penetrant risk factor.
Project description:SETD5, a gene linked to intellectual disability (ID) and autism spectrum disorder (ASD), is a member of the SET-domain family and encodes a putative histone methyltransferase (HMT). To date, the mechanism by which SETD5 haploinsufficiency causes ASD/ID remains an unanswered question. Setd5 is the highly conserved mouse homolog, and although the Setd5 null mouse is embryonic lethal, the heterozygote is viable. Morphological tracing and multi electrode array was used on cultured cortical neurons. MRI was conducted of adult mouse brains and immunohistochemistry of juvenile mouse brains. RNA-Seq was used to investigate gene expression in the developing cortex. Behavioral assays were conducted on adult mice. Setd5+/- cortical neurons displayed significantly reduced synaptic density and neuritic outgrowth in vitro, with corresponding decreases in network activity and synchrony by electrophysiology. A specific subpopulation of fetal Setd5+/- cortical neurons showed altered gene expression of neurodevelopment-related genes. Setd5+/- animals manifested several autism-like behaviors, including hyperactivity, cognitive deficit, and altered social interactions. Anatomical differences were observed in Setd5+/- adult brains, accompanied by a deficit of deep-layer cortical neurons in the developing brain. Our data converge on a picture of abnormal neurodevelopment driven by Setd5 haploinsufficiency, consistent with a highly penetrant risk factor.
Project description:Setd5 inactivation in neural stem cells, zebrafish and mouse leads to a significant H3K36 hypo-methylation mostly detectable along the gene bodies. Consequently, this chromatin alteration perturbs RNA processing during elongation, compromising the transcriptional output. This gene dysregulation affects proliferative dynamics of NSCs and synaptic wiring in the neuronal derivatives, ultimately resulting in behavioral deficits in adult mice.
Project description:SETD5 gene mutations have been identified as a frequent cause of idiopathic intellectual disability. Here we show that Setd5 haploinsufficient mice present developmental defects such as abnormal brain to body weight ratio and neural crest defect associated phenotypes. Furthermore, Setd5 mutant mice show impairments in cognitive tasks, enhanced long-term potentiation, delayed ontogenetic profile of ultrasonic vocalisation and behavioural inflexibility. Behavioural issues are accompanied by abnormal expression of postsynaptic density proteins previously associated with cognition. Our data suggest that Setd5 might regulate RNA polymerase II dynamics and gene transcription during development and learning via its interaction with the Hdac3 and Paf1 complexes. Our results emphasize the decisive role of Setd5 in a biological pathway found to be disrupted in intellectual disability and autism spectrum disorder patients.
Project description:SET-domain containing proteins play a vital role in regulating gene expression during development through modifications in chromatin structure. To study molecular function of SET domain containing 5 (Setd5), we assessed global changes in the mouse embryonic stem cell transcriptome when Setd5 gene is knocked out.
Project description:Setd5 inactivation in neural stem cells, zebrafish and mouse leads to a significant H3K36 hypo-methylation mostly detectable along the gene bodies. Consequently, this chromatin alteration perturbs RNA processing during elongation, compromising the transcriptional output. This gene dysregulation affects proliferative dynamics of NSCs and synaptic wiring in the neuronal derivatives, ultimately resulting in behavioral deficits in adult mice.