Epigenetic-metabolic aspects of alcohol use disorder and early developmental alcohol exposure

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PROJECT SUMMARY/ABSTRACT Alcohol use disorder (AUD) continues to impose a tremendous burden on society and efficacious treatment options are severely lacking. Recently, epigenetic processes such as histone acetylation emerged as potential contributors to AUD. Acetylation of histones has been shown to facilitate DNA accessibility and gene expression. The dynamic and reversible nature of this process makes it a particularly promising potential therapeutic target. Novel evidence suggests that epigenetic regulation is dependent on metabolic state, implicating specific metabolic factors in neural functions that drive behavior (Li*, Egervari* et al, Nat Rev Mol Cell Biol 2018). Recently, our group has shown that neuronal histone acetylation is fueled by the metabolite acetyl-CoA that is produced from acetate by nuclear Acetyl-CoA Synthetase 2 (ACSS2; Mews et al, Nature 2017). As a major biological source of acetate is alcohol metabolism, I hypothesized that alcohol-derived acetate might have profound effects on the epigenetic landscape in the brain following binge drinking. Using heavy isotope labeling in mice, I showed that alcohol metabolism rapidly promotes histone acetylation in the brain by direct deposition of alcohol-derived acetyl groups onto histones in an ACSS2-dependent manner. I observed similar incorporation of alcohol-derived acetate into fetal brain, suggesting a potential role for ACSS2 during prenatal alcohol exposure. In adult mice, alcohol-induced histone acetylation led to increased expression of key neuronal genes linked to learning and memory. Strikingly, ACSS2 was required for ethanol-induced associative learning, which underlies craving and relapse after protracted periods of abstinence (Mews*, Egervari*# et al, Nature, 2019). These preliminary findings establish a direct and dynamic link between peripheral and central alcohol metabolism and brain histone acetylation with significant therapeutic potential. In this proposal, I will aim to (1) determine the importance of ACSS2 in voluntary alcohol intake and test whether ACSS2 inhibition decreases alcohol consumption in mice; (2) characterize the role of ACSS2 in prenatal alcohol exposure and in the development of fetal alcohol spectrum disorder; and (3) explore the potential relevance of this novel pathway in various brain regions that regulate different aspects of AUD. This study will make pioneering contributions to our understanding of alcohol’s effects on the brain with respect to epigenetic and metabolic processes, and has the potential to identify new pharmaceutical targets to ameliorate alcohol use disorder. In addition, the proposed training and research will greatly facilitate my transition to an independent tenured-track faculty position. I will learn a combination of computational, genomic and proteomic techniques and behavioral approaches that will help establish my niche and provide me with the skills necessary to work at the intersection of epigenetics, metabolism and alcohol neurobiology. With the acquisition of valuable skills that I describe in the training plan of this proposal, I will be in a unique position to reveal new insights into the role of epigenetic-metabolic regulation of brain function in the context of alcohol use.