Non-CG methylation and multiple epigenetic layers associate child abuse with immune and small GTPase dysregulation
Early-life adversity (ELA) is a major predictor of psychopathology, and is thought to increase lifetime risk by epigenetically regulating the genome. Here, focusing on the lateral amygdala, a major brain site for emotional homeostasis, we described molecular cross-talk among multiple epigenetic mechanisms, including 6 histone marks, DNA methylation and the transcriptome, in subjects with a history of ELA and controls. We first uncovered, in the healthy brain, previously unknown interactions among epigenetic layers, in particular related to non-CG methylation in the CAC context. We then showed that ELA associates with methylomic changes that are as frequent in the CAC as in the canonical CG context, while these two forms of plasticity occur in sharply distinct genomic regions, features, and chromatin states. Combining these multiple data indicated that immune-related and small GTPase signaling pathways are most consistently impaired in the amygdala of ELA individuals. Overall, this work provides new insights into epigenetic brain regulation as a function of early-life experience. Overall design: Examination of gene expression, DNA methylation and 6 histone marks in human brain tissue samples from the lateral amygdala, and comparison to gene expression data generated in another brain region, the anterior cingulate cortex (data first reported in Lutz, Tanti et al, The American Journal Of Psychiatry 2017, 174:12)