PROJECT SUMMARY This proposal brings together experts in the genomics of neuropsychiatric disorders and translational neuroscience to investigate the molecular pathology of alcohol use disorder (AUD). Alcohol use is the fourth leading cause of preventable death in the United States that affects over 16 million adults. Understanding the molecular basis for individual differences in susceptibility to alcohol addiction will facilitate the development of diagnostics and personalized therapeutics. Brain molecular phenotypes, such as gene expression and DNA methylation can be translated into neurobiological mechanisms by identifying causal disease genes and pathways. The central goal of this research is to identify novel lasting transcriptomic and epigenetic changes in biological pathways harboring potential biomarkers and therapeutic targets for AUD. Our central hypothesis is that genetic and epigenetic variations lead to brain region-specific dysregulation of transcriptomic networks and disturbances in reward-related genes during AUD. This proposal will perform a postmortem, multi-omic study of brains from 341 total subjects AUD (n=100), a psychiatric control (MDD; N = 132) and neurotypical controls (n=109). To test our hypothesis, we will determine differential DNA methylation and RNA expression across 8 total brain areas of the prefrontal cortex, amygdala, nucleus accumbens and hippocampus. We will analyze RNA-sequencing of 8 discrete regions to identify transcriptional changes in etiologically relevant AUD brain regions (Aim 1). Next, we will identify gene regulatory mechanisms of AUD by integrating whole-genome bisulfite sequencing of matched donors and regions (Aim 2). Finally, we will prioritize AUD genes and test whether genome-wide significant variants identified from GWAS of AUD and alcohol-related phenotypes are associated with gene expression or DNA methylation across brain regions (Aim 3). The expected outcome of this research will be a model of genetic, epigenetic, and transcriptomic profiles of brain regions from cases versus controls that will allow us to understand the region-specific molecular effects of AUD. By identifying new molecular mechanisms of AUD using a large number of donors across many regions, we will be able to explicate the neurobiological mechanisms affected by AUD and identify novel targets for intervention in the addiction process.