Project description:Huntington’s disease (HD) and juvenile-onset schizophrenia (SCZ) have long been regarded as distinct disorders. However, both manifest cell-intrinsic abnormalities in glial differentiation, with resultant astrocytic dysfunction and hypomyelination. To assess whether a common mechanism might underlie the similar glial pathology of these otherwise disparate conditions, we utilized comparative correlation network approaches to analyze RNA-seq data from human glial progenitor cells (hGPCs) produced from disease-derived pluripotent stem cells. We identified gene sets preserved between HD and SCZ hGPCs yet distinct from normal controls, that included 174 highly-connected genes in the shared disease-associated network, focused on genes involved in synaptic signaling. These synaptic genes were largely suppressed in both SCZ and HD hGPCs, and gene regulatory network analysis identified a core set of upstream regulators of this network, of which OLIG2 and TCF7L2 were prominent. Among their downstream targets, ADGRL3, a modulator of glutamatergic synapses, was notably suppressed in both SCZ and HD hGPCs. ChIP-seq confirmed that OLIG2 and TCF7L2 each bound to the regulatory region of ADGRL3, whose expression was then rescued by lentiviral overexpression of these transcription factors. These data suggest that the disease-associated suppression of OLIG2 and TCF7L2-dependent transcription of glutamate signaling regulators may impair glial receptivity to neuronal glutamate. The consequent loss of activity-dependent mobilization of hGPCs may yield deficient oligodendrocyte production, and hence the hypomyelination noted in these disorders, as well as the disrupted astrocytic differentiation and attendant synaptic dysfunction associated with each. Together, these data highlight the importance of convergent glial molecular pathology in both the pathogenesis and phenotypic similarities of two otherwise unrelated disorders, HD and SCZ.
Project description:Huntington’s disease (HD) and juvenile-onset schizophrenia (SCZ) have long been regarded as distinct disorders. However, both manifest cell-intrinsic abnormalities in glial differentiation, with resultant astrocytic dysfunction and hypomyelination. To assess whether a common mechanism might underlie the similar glial pathology of these otherwise disparate conditions, we utilized comparative correlation network approaches to analyze RNA-seq data from human glial progenitor cells (hGPCs) produced from disease-derived pluripotent stem cells. We identified gene sets preserved between HD and SCZ hGPCs yet distinct from normal controls, that included 174 highly-connected genes in the shared disease-associated network, focused on genes involved in synaptic signaling. These synaptic genes were largely suppressed in both SCZ and HD hGPCs, and gene regulatory network analysis identified a core set of upstream regulators of this network, of which OLIG2 and TCF7L2 were prominent. Among their downstream targets, ADGRL3, a modulator of glutamatergic synapses, was notably suppressed in both SCZ and HD hGPCs. ChIP-seq confirmed that OLIG2 and TCF7L2 each bound to the regulatory region of ADGRL3, whose expression was then rescued by lentiviral overexpression of these transcription factors. These data suggest that the disease-associated suppression of OLIG2 and TCF7L2-dependent transcription of glutamate signaling regulators may impair glial receptivity to neuronal glutamate. The consequent loss of activity-dependent mobilization of hGPCs may yield deficient oligodendrocyte production, and hence the hypomyelination noted in these disorders, as well as the disrupted astrocytic differentiation and attendant synaptic dysfunction associated with each. Together, these data highlight the importance of convergent glial molecular pathology in both the pathogenesis and phenotypic similarities of two otherwise unrelated disorders, HD and SCZ.
Project description:Huntington’s disease (HD) and juvenile-onset schizophrenia (SCZ) have long been regarded as distinct disorders. However, both manifest cell-intrinsic abnormalities in glial differentiation, with resultant astrocytic dysfunction and hypomyelination. To assess whether a common mechanism might underlie the similar glial pathology of these otherwise disparate conditions, we utilized comparative correlation network approaches to analyze RNA-seq data from human glial progenitor cells (hGPCs) produced from disease-derived pluripotent stem cells. We identified gene sets preserved between HD and SCZ hGPCs yet distinct from normal controls, that included 174 highly-connected genes in the shared disease-associated network, focused on genes involved in synaptic signaling. These synaptic genes were largely suppressed in both SCZ and HD hGPCs, and gene regulatory network analysis identified a core set of upstream regulators of this network, of which OLIG2 and TCF7L2 were prominent. Among their downstream targets, ADGRL3, a modulator of glutamatergic synapses, was notably suppressed in both SCZ and HD hGPCs. ChIP-seq confirmed that OLIG2 and TCF7L2 each bound to the regulatory region of ADGRL3, whose expression was then rescued by lentiviral overexpression of these transcription factors. These data suggest that the disease-associated suppression of OLIG2 and TCF7L2-dependent transcription of glutamate signaling regulators may impair glial receptivity to neuronal glutamate. The consequent loss of activity-dependent mobilization of hGPCs may yield deficient oligodendrocyte production, and hence the hypomyelination noted in these disorders, as well as the disrupted astrocytic differentiation and attendant synaptic dysfunction associated with each. Together, these data highlight the importance of convergent glial molecular pathology in both the pathogenesis and phenotypic similarities of two otherwise unrelated disorders, HD and SCZ.
Project description:Genetic studies have suggested a role for glial pathology in the genesis of schizophrenia (SCZ). To assess the nature of SCZ-associated human glial dysfunction in vivo, we established human glial chimeric mice using glial progenitor cells (GPCs) produced from induced pluripotential cells (hiPSCs), derived from patients with juvenile-onset schizophrenia or healthy controls. To this end, hiPSC GPCs were implanted neonatally into either immunodeficient myelin wild-type mice, in which donor GPCs remained as progenitors or became astrocytes, or into myelin-deficient shiverer mice, in which the GPCs also gave rise to oligodendrocytes. When implanted into shiverers, the SCZ-derived GPCs exhibited less expansion in the white matter than did control GPCs, instead migrating prematurely into the cortex. The SCZ GPC-transplanted shiverers were consequently hypomyelinated relative to control GPC-engrafted mice. When established instead in myelin wild-type hosts, the SCZ hiPSC glial chimeras manifested markedly delayed and diminished astrocytic differentiation, which was associated with diminished prepulse inhibition and an aberrant behavioral phenotype across multiple modalities. Accordingly, RNA-seq revealed significant differences in both glial differentiation-associated and synaptic gene expression by SCZ GPCs. These data suggest a potent contribution of cell-autonomous glial dysfunction to the development of schizophrenia, and provide a model for the in vivo assessment of human glial pathology in this disorder.
Project description:A large portion of common variant loci associated with genetic risk for schizophrenia reside within non-coding sequence of unknown function. Here, we demonstrate promoter and enhancer enrichment in schizophrenia variants associated with expression quantitative trait loci (eQTL). The enrichment is greater when functional annotations derived from human brain are used relative to peripheral tissues. Regulatory trait concordance analysis ranked genes within schizophrenia genome-wide significant loci, based on co-localization of a risk SNP, eQTL and regulatory element sequence. These include physical interactions of non-contiguous gene-proximal and distal elements bypassing the linear genome, which was verified in prefrontal cortex and human induced pluripotent stem cell derived neurons for the L-type calcium channel (CACNA1C) risk locus. Our findings point to a functional link between schizophrenia-associated non-coding SNPs and 3-dimensional genome architecture associated with chromosomal loopings and transcriptional regulation in the brain. Examination of H3K4me3 histone modifications in 3 samples.
Project description:Hdac4 has been found to modulate symptoms in Huntington's Disease (HD) mouse models through an uknown mechanism unrelated to any enzymatic activity. We investigated the protein-protein interactions to gain insight into the role of Hdac4 in HD.