Defining the Role of MAT2A in Alcohol Use Disorder

PROJECT SUMMARY Alcohol use disorder (AUD) is a chronic condition characterized by persistent neuroadaptive changes that drive alcohol-seeking and consumption. Emerging research highlights the crucial role of epigenetic regulation and chromatin remodeling in addiction, particularly through histone methylation. Alcohol exposure increases trimethylation of histone 3 at lysine 4 (H3K4me3) in hippocampal neurons, an activating mark associated with gene transcription. However, the underlying mechanisms of these epigenetic changes remain unclear, particularly the role of metabolic pathways that provide the central cofactor and methyl-group donor required for histone methylation: S-adenosylmethionine (SAM). This project aims to elucidate the role of methionine adenosyltransferase 2A (MAT2A), the enzyme in the methionine cycle that produces SAM, in alcohol-induced histone methylation and subsequent gene regulation. We hypothesize that MAT2A interacts with specific genomic loci in hippocampal neurons, influencing local H3K4me3 states upon alcohol exposure, leading to disrupted gene regulatory events and further alcohol-seeking behavior. Preliminary data suggests that MAT2A translocates to the nucleus of neurons in response to chemical stimulation. In Aim 1, I will determine MAT2A subcellular localization changes during alcohol exposure using subcellular fractionation combined with western blotting, immunofluorescence, and ChIP-sequencing. This will provide insight into how alcohol influences the movement and expression of MAT2A within the cell and its potential interactions with chromatin. In Aim 2, I will assess the necessity of MAT2A for alcohol-induced H3K4me3 by knocking down MAT2A using viral vectors. Additionally, I will test whether the SAM-producing function of MAT2A drives these changes by supplementing with SAM after MAT2A knockdown. Finally, Aim 3 will strive to connect these molecular events to behavioral outcomes. I will evaluate the impact of MAT2A knockdown on alcohol-consumption behavior in a voluntary binge-drinking model, using the 2-bottle-choice drinking-in-the-dark paradigm. Together, this research will uncover critical molecular mechanisms of alcohol exposure in the brain, exploring the intersection of epigenetics and metabolic enzymes. Our findings may identify novel therapeutic targets for alcohol use disorder, potentially offering new avenues for treatment and prevention strategies.