Pluto Bioinformatics

GSE120423: Brain transcriptome profiling in wildtype mice and mice with Igf2 enhancer deletion (Igf2enh-/-) [RNA-seq]

Bulk RNA sequencing

Impaired neuronal processes, including dopamine imbalance, are central to the pathogenesis of major psychosis, but the molecular origins are unclear. We report the first multi-omics study of neurons isolated from the prefrontal cortex of individuals with schizophrenia and bipolar disorder, including genome-wide neuronal DNA methylation using Illumina EPIC microarrays, transcriptomes and SNP genotypes (n=55 cases and 27 controls). Epigenetic, transcriptomic, and genetic-epigenetic interactions in disease converged on pathways of neurodevelopment, synaptic activity, and immune functions. Notably, we discovered prominent hypomethylation of an enhancer within the insulin-like growth factor 2 (IGF2) gene in neurons of major psychosis patients. Chromatin conformation analysis revealed that this enhancer targets the nearby tyrosine hydroxylase (TH) gene, which is responsible for dopamine synthesis. IGF2 enhancer hypomethylation was associated with increased TH protein levels in the human brain. The Igf2 enhancer was deleted in mice to explore the transcriptomic and proteomic consequences of this genomic locus in the frontal cortex and striatum. In mice, Igf2 enhancer deletion disrupted levels of TH protein and striatal dopamine, as well as induced transcriptional and proteomic abnormalities affecting development and synaptic function. Epigenetic control of the IGF2 enhancer may regulate dopamine levels and contribute to psychosis risk. SOURCE: Shraddha Pai (shraddha.pai@utoronto.ca) - University of Toronto