Alcohol-Induced Epigenetic Changes in Stem Cells

描述（由申请人提供）：饮酒会对包括肝脏和大脑在内的多个器官造成损害，乙醇可以通过改变DNA甲基化和组蛋白来影响细胞的表观遗传状态。这些表观遗传变化可能损害组织再生，使细胞易发生肿瘤转化，和/或改变干细胞或分化细胞的功能。在测试乙醇对小鼠胚胎干细胞（ES）细胞影响的初步实验中，我们观察到乙醇和乙醛（乙醇的代谢物）对基因表达和组蛋白修饰的一些显著影响。事实上，我们已经有数据表明，酒精会影响Polycomb suppression Complex 2的活性，Polycomb suppression Complex 2是一种多蛋白复合物，是干细胞分化的主要负表观遗传调节剂。基于这些初步结果，我们的假设是酒精和乙醛诱导干细胞的表观遗传变化，影响干细胞正常分化的能力。在目标(1)中，我们提出

DESCRIPTION (provided by applicant): Alcohol consumption causes damage to multiple organs, including the liver and brain, and ethanol can affect the epigenetic state of cells by modifying DNA methylation and modifying histones. These epigenetic changes may compromise regeneration of tissues, predispose cells to become neoplastically transformed, and/or alter the function of stem cells or differentiated cells. In pilot experiments testing the effects of ethanol on murine embryonic stem (ES) cells, we observed some striking effects of ethanol and acetaldehyde, a metabolite of ethanol, on both gene expression and on histone modifications. Indeed, we already have data suggesting that alcohol influences the activity of the Polycomb Repressive Complex 2, a multi-protein complex that is a central negative epigenetic regulator of stem cell differentiation. Based on these preliminary results, our hypothesis is that alcohol and acetaldehyde induce epigenetic changes in stem cells, influencing the ability of such stem cells to undergo normal differentiation. In Aim (1) we propose to determine the global effects of alcohol and acetaldehyde on the epigenetic state of murine embryonic stem (ES) cells by performing genome-wide analysis using chromatin immunoprecipitation-sequencing (ChIP-Seq) and quantifying genome-wide changes in DNA methylation by Reduced-Representation Bi-sulfite Sequencing (RRBS). In Aim (2) we will determine how changes in the epigenetic state induced by alcohol and acetaldehyde affect gene expression and the differentiation of ES cells by performing genome-wide analysis using RNA-seq technology and by interpreting these changes in light of the changes in chromatin structure (Aim 1). We will use all-trans retinoic acid (RA), a signaling molecule that induces ES cell differentiation, as a positive control in Aim (1) since we and others have shown that RA can change the epigenetic state of ES cells. Since alcohol causes tissue injury, requiring stem cells in adult tissues to proliferate and differentiate repeatedly in an attempt to repair the damage, ou studies will lead to insights into the mechanisms by which alcohol both causes tissue injury and compromises response to tissue injury. We hypothesize that alcohol-induced epigenetic changes may underlie disorders as diverse as addictive behavior, tumor formation, and cirrhosis of the liver. Moreover, unlike genetic mutations that change the DNA sequence and are generally permanent, epigenetic changes can be reversed and therefore are reasonable targets for therapies to treat alcohol-induced tissue injury. PUBLIC HEALTH RELEVANCE: Alcohol abuse is a major global problem, resulting in tissue injury and disease. We propose to perform experiments in stem cells that will delineate the effects of alcohol and a metabolite of alcohol, acetaldehyde, on histones, proteins that surround DNA in cells. The new information we gain from this project will be critical for understanding alcohol- associated tissue injury since stem cells are continually differentiating throughout life, and may lead to new types of "epigenetic" drug treatments for alcohol-associated tissue injury.