Epigenetic mechanisms of positive affective state of AUD

University Of Illinois At Chicago, Chicago IL

Investigators

Linked publications, trials & patents

Abstract

Project Summary/Abstract The withdrawal syndrome of alcohol use disorder (AUD) includes both negative symptoms, like anxiety, and motivational symptoms such as craving for alcohol, which promotes relapse and alcohol seeking. Understanding how alcohol withdrawal changes brain physiology is an important step towards developing effective treatments to reduce alcohol abuse. The ventral tegmental area (VTA) is an important brain area that projects to components of the extended amygdala, including the nucleus accumbens, prefrontal cortex, amygdala and hippocampus. Changes in the physiology of VTA neurons induced by withdrawal may underlie the alcohol-seeking during AUD. The sensitivity of neurons of the VTA to inhibition by gamma aminobutyric acid (GABA) is decreased during alcohol withdrawal but is normalized by histone deacetylase (HDAC) inhibitors, indicating epigenetic changes induced by withdrawal in the VTA may be amenable to pharmacological manipulation. Whole genome sequencing and molecular studies of this project identified clusters of genes associated with cholesterol synthesis pathway enzymes that were downregulated and genes for neuroimmune factors that were upregulated during withdrawal. The proposed project plans to extend our findings to characterize the specific cell types of the VTA in which these withdrawal-regulated genes are located and how they affect withdrawal-induced phenotypes of morphology, electrophysiology, and behavior. By using state-of-the-art techniques of 10x genomics, 3-D electron microscopy, spatial transcriptomics, electrophysiological, behavioral, and cutting edge molecular biological methods, we anticipate achieving the following goals: 1) to characterize the epigenetic mechanisms controlling upregulation of neuroimmune gene expression during withdrawal, 2) to use single nucleus (sn)RNA-seq and snATAC-seq to determine cell-specific differential expression of genes and chromatin accessibility for selected genes in the VTA during withdrawal, and to validate the cell-specific expression with spatial transcriptomics, immunohistochemistry, and chromatin immunoprecipitation, 3) to use CRISPR- dCas9 plus single guide RNA with cell-specific promoters to prevent withdrawal-induced alteration of gene expression in specific cell types and determine how this prevention alters withdrawal- induced phenotypes. Ultimately, these studies are needed to understand epigenetic adaptation of VTA neurons involved in the positive affective state during alcohol withdrawal, and, with the other components of this Center, will provide a great deal of information on epigenetic mechanisms involved in withdrawal-induced brain changes, and possible pharmacological approaches toward more effective treatment of AUD.