Epigenetic mechanisms of negative affective state of AUD

University Of Illinois At Chicago, Chicago IL

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Abstract

Project Summary: Preclinical and clinical evidence suggests that anxiety withdrawal symptoms associated with alcohol withdrawal are a primary risk factor for relapse and maintenance of alcohol use disorder (AUD). Central nucleus of amygdala (CeA) represents well-connected nuclei within extended amygdala and are implicated in anxiety and fear related behaviors. Previous studies have shown that epigenetic mechanisms due to histone and DNA chemical modifications play important roles in the regulation of gene expression during ethanol exposure. This research project of CARE is based on the hypothesis that withdrawal after chronic ethanol exposure will produce transcriptomic and open chromatin accessibility changes in a cell-specific manner in the CeA of both sexes. These cell type-specific molecular mechanisms will produce abnormal structural and electrophysiological changes in the CeA leading to development of anxiety-like behaviors. This hypothesis will be tested by following specific aims: 1a) To establish the causal role of histone methyltransferases, enhancer of zeste homolog 2 (EZH2) in the regulation of synaptic genes, ex-vivo whole patch-clamp electrophysiological responses, structural changes in the CeA, as well as behavioral phenotypes of anxiety in male and female rats during ethanol withdrawal. 1b) To translate rat amygdala findings to the postmortem amygdala of human subjects with AUD and characterize these genes epigenetically. 2) To investigate cell type-specific transcriptomic and epigenomic changes using 10x genomics (snRNA-seq and snATAC-seq; omics approach) in the CeA of male and female rats undergoing withdrawal after chronic ethanol exposure. The emerging epigenetically regulated genes within the same cells will be identified and validated using spatial transcriptomics. 3) To examine whether infusion of cell-type specific dCas9-P300 or dCas9-KRAB lentivirus into the CeA to target differentially expressed genes during ethanol withdrawal would normalize aberrant epigenetic and gene expression changes, microstructural changes (spines and synapses-3D electron microscopic studies) and restore inhibitory/excitatory neurotransmission in the CeA leading to attenuation of anxiety-like behaviors in both sexes in rats. Completion of these studies will provide new information on the epigenetic regulation of transcriptome in the same cells of CeA, leading to identification of epigenetic targets for the development of pharmacotherapy of AUD.