Chunk #19 — 3. Biological co-expression networks: Transcriptional regulation in alcohol use disorder — 3.1: Epigenetic modifications in the human alcoholic brain
cocaine users (Farris et al., 2015a). In contrast to the modest effects observed previously (Zhou et al., 2011), Farris and colleagues observed 35 significant overlaps between the two datasets with 83% of modules having a significant positive correlation between H3K4me3 and transcript abundance. This provided evidence for coordinated regulation of several gene sets in parallel to H3K4me3 modification, suggesting a potential causative relationship between these events. Comparison of these results with previously published gene networks in alcoholic superior frontal cortex (Ponomarev et al., 2012) showed that alcohol-regulated modules overlapped across brain regions, with the majority of genes in these modules being regulated in the same direction in both studies. Collectively, transcriptomic studies suggest that chronic alcohol consumption or cocaine use alters regulation of transcription via system-wide epigenetic modifications in brain.
