Alcohol is one of the most widely used addictive drugs in adolescence and continued use and abuse can lead to the development of psychiatric disorders including alcoholism in adulthood. Adolescents show differential sensitivity to alcohol as compared to adults. Both genetic and environmental risk factors play roles in the development of alcoholism. Genetic studies in human and animal models of alcoholism have identified genes that may be critical in the pathophysiology of alcoholism. Epigenetic mechanisms, involved in the regulation of gene expression, have recently emerged as a promising area of research into neuropsychiatric illnesses and enabled us to better understand the molecular mechanisms of human diseases, including psychiatric and alcohol use disorders. Epigenetic processes, such as histone acetylation and DNA methylation mechanisms, have been shown to play a role in neuromaturation by contributing to the stability of gene expression during brain development. NADIA (Neurobiology of Adolescent Drinking in Adulthood) studies have identified several genes and molecular pathways in key brain regions that are altered by adolescent intermittent ethanol (AIE) exposure and that are involved in neuroinflammation, synaptic plasticity and neurogenesis. However, the epigenetic mechanisms operative in the etiology of AIE-induced pathology in adulthood are still underexplored. The major objective of the Epigenetic/Molecular core is to provide the resources for experimental analyses of a subset of gene targets to each Research Component of NADIA, in order to understand epigenetic mechanisms that are operative in AIE- induced molecular and behavioral changes under investigation. We hypothesize that perturbations of epigenetic processes due to AIE may lead to dynamic changes in transcription in key brain circuitries (prefrontal cortex, amygdala, hippocampus, hypothalamus, septum, ventral tegmental area, and nucleus accumbens) that are responsible for persistent behavioral and neurochemical phenotypes in adulthood. The following Specific Aims will test this hypothesis: 1) To examine AIE-induced changes in mRNA levels of selected target genes for each research component of NADIA using real-time quantitative PCR (qPCR). 2) To examine AIE-induced histone modifications (histone H3-K9 acetylation/methylation) associated with target gene promoters for each project using chromatin immunoprecipitation (ChIP) followed by qPCR. 3) To examine DNA methylation status of promoters of target genes using methyl DNA immunoprecipitation (MeDIP) or methyl-CpG binding domain (MBD) based- assays (MethylMiner(tm)) followed by qPCR. The Core will also examine levels of 5-hydroxymethylcystosine of target genes promoters using 5- hydroxymethylcytosine immunoprecipitation (hMeDIP) assays. This core will be able to examine epigenetic mechanisms underlying AIE-mediated changes in gene expression in various brain regions across NADIA. This effort will identify common molecular targets within the epigenome that may lead to the development of novel treatment strategies for adult psychopathologies resulting from adolescent binge drinking.
Binge drinking is very common in adolescents and continued abuse by this population can lead to the development of psychiatric disorders including alcoholism in adulthood. The proposed studies will continue to elucidate the molecular mechanisms of adolescent intermittent ethanol (AIE)-induced behavioral phenotypes in adulthood that are under investigation by the NADIA consortium. These studies will lead to the development of epigenetic-based therapies for adolescent binge drinking induced psychopathology in adulthood.
