Project description:There are hundreds of risk genes for autism spectrum disorder (ASD), but signaling networks at the protein level remain unexplored. We used neuron-specific proximity-labeling proteomics (BioID) to identify protein-protein interaction (PPI) networks for 41 ASD-risk genes. Neuron-specific PPI networks included synaptic transmission proteins, which are disrupted by de novo missense variants. The PPI network map revealed convergent pathways including mitochondrial/metabolic processes, Wnt signaling, ion channel activity and MAPK signaling. CRISPR knockout validations revealed an association between mitochondrial activity and ASD-risk genes. The PPI network showed an enrichment of 112 additional ASD-risk genes and differentially expressed genes from post-mortem ASD patients. Clustering of risk genes based on PPI networks identified gene groups corresponding to clinical behavior score severity. Our data reveal that cell type-specific PPI networks can identify previously unknown individual and convergent ASD signaling networks, provide a method to assess patient variants, and reveal biological insight into disease mechanisms and sub-cohorts of ASD.
Project description:Many autism spectrum disorder (ASD)-associated genes act as transcriptional regulators (TRs). ChIP-seq was used to identify the regulatory targets of ARID1B, BCL11A, FOXP1, TBR1, and TCF7L2, ASD-associated TRs in the developing human and mouse cortex. These TRs shared substantial overlap in the binding sites, especially within open chromatin. The overlap within a promoter region, 1-2,000bp upstream of transcription start site, was highly predictive of brain expressed genes. This signature was observed at 96 out of 102 ASD-associated genes. In vitro CRISPRi against ARID1B and TBR1 delineated downstream convergent biology in mouse cortical cultures. After eight days, NeuN+ and CALB+ cells were decreased, GFAP+ cells were increased, and transcriptomic signatures correlated with the postmortem brain samples from individuals with ASD. We suggest functional convergence across five ASD-associated TRs leads to shared neurodevelopmental outcomes of haploinsufficient disruption.
Project description:Autism Spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder where patients have impaired social behavior and communication, and restricted interests. Although various studies have been carried out to unveil the mechanisms associated with ASD, its pathophysiology is still poorly understood. Genetic variants on CNTNAP2 have been found and considered representative ASD genetic risk factors, and disruption of Cntnap2 causes ASD phenotypes in mice. Here, we performed an integrative multi-omics analysis by combining quantitative proteometabolomics data of Cntnap2 knockout (KO) mice with multi-omics data from ASD patients and forebrain organoids to elucidate Cntnap2-dependent molecular networks of ASD. First, we found Cntnap2-associated molecular signatures and cellular processes by conducting mass spectrometry-based proteometabolomic analysis of the medial prefrontal cortex of the Cntnap2 KO mouse model. Then, we narrowed these identified processes into bona fide ASD molecular processes by incorporating multi-omics data of ASD patients' prefrontal cortex. Further, we mapped cell-type-specific ASD networks by reanalyzing single-cell RNA-seq data of forebrain organoids derived from patients with CNTNAP2 mutation. Finally, we constructed a Cntnap2-associated ASD network model consisting of mitochondrial dysfunction, axonal impairment, and synaptic activity. Our results may shed light on understanding of the Cntnap2-dependent molecular networks of ASD.
Project description:Whole-exome sequencing studies have implicated chromatin modifiers and transcriptional regulators in autism spectrum disorder (ASD) through the identification of de novo loss of function mutations in affected individuals. Many of these genes are co-expressed in mid-fetal human cortex, suggesting ASD risk genes converge in regulatory networks that are perturbed in ASD during neurodevelopment. To elucidate such networks we mapped promoters and enhancers bound by the chromodomain helicase CHD8, which is strongly enriched in ASD-associated de novo loss of function mutations, using ChIP-seq in mid-fetal human brain, human neural stem cells (hNSCs), and embryonic mouse cortex. We find that CHD8 targets are strongly enriched for ASD risk genes that converge in ASD-associated co-expression networks in human midfetal cortex. CHD8 knockdown in hNSCs results in significant dysregulation of ASD risk genes targeted by CHD8, as well as additional genes important for neurodevelopment, including members of the Wnt/M-NM-2-catenin signaling pathway. Integration of CHD8 binding data with genetic and gene co-expression data in ASD risk models provides support for additional ASD risk genes. Together, our results suggest that loss of CHD8 function contributes to ASD through regulatory perturbation of other ASD risk genes during human cortical development. Two biological replicates for each ChIP with appropriate Input control Four biological replicates for each condition in knockdown experiments (Ctrl construct, Chd8 target C, and Chd8 target G)
Project description:Whole-exome sequencing studies have implicated chromatin modifiers and transcriptional regulators in autism spectrum disorder (ASD) through the identification of de novo loss of function mutations in affected individuals. Many of these genes are co-expressed in mid-fetal human cortex, suggesting ASD risk genes converge in regulatory networks that are perturbed in ASD during neurodevelopment. To elucidate such networks we mapped promoters and enhancers bound by the chromodomain helicase CHD8, which is strongly enriched in ASD-associated de novo loss of function mutations, using ChIP-seq in mid-fetal human brain, human neural stem cells (hNSCs), and embryonic mouse cortex. We find that CHD8 targets are strongly enriched for ASD risk genes that converge in ASD-associated co-expression networks in human midfetal cortex. CHD8 knockdown in hNSCs results in significant dysregulation of ASD risk genes targeted by CHD8, as well as additional genes important for neurodevelopment, including members of the Wnt/β-catenin signaling pathway. Integration of CHD8 binding data with genetic and gene co-expression data in ASD risk models provides support for additional ASD risk genes. Together, our results suggest that loss of CHD8 function contributes to ASD through regulatory perturbation of other ASD risk genes during human cortical development.
Project description:Hundreds of genes are implicated in autism spectrum disorder (ASD) but the mechanisms through which they contribute to ASD pathophysiology remain elusive. Here, we analyzed leukocyte transcriptomics from 1-4 year-old male toddlers with ASD or typical development from the general population. We discovered a perturbed gene network that includes genes highly expressed during fetal brain development and which is dysregulated in hiPSC-derived neuron models of ASD. High-confidence ASD risk genes emerge as upstream regulators of the network, and many risk genes may impact the network by modulating RAS/ERK, PI3K/AKT, and WNT/-catenin signaling pathways. We found that the degree of dysregulation in this network correlated with the severity of ASD symptoms in the toddlers. These results demonstrate how the heterogeneous genetics of ASD may dysregulate a core network to influence brain development at prenatal and very early postnatal ages and, thereby, the severity of later ASD symptoms.