Epigenetic regulation of alcoholic steatohepatitis in a mouse model

小鼠模型中酒精性脂肪性肝炎的表观遗传调控

• 批准号: 8322621
• 负责人: CHARLES HOPKINSON HALSTED
• 金额: $ 7.7万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8322621
• 关键词: Acetylation; Acetylesterase; Address; Affect; Alcohol consumption; Alcoholic Liver Diseases; Apoptosis; Betaine; Cystathionine beta-Synthase; DNA; DNA Methylation; DNA Methyltransferase; DNA Modification Methylases; DNA Modification Process; Data; Development; Diet; Dietary Supplementation; Disease; Epigenetic Process; Ethanol; Exposure to; Fibrosis; Future; Gene Activation; Gene Expression; Gene Expression Regulation; Genes; Genotype; Hepatic; Hepatocyte; Histone Acetylation; Histones; Histopathology; Individual; Inflammatory Response; Injury; Injury to Liver; Lipids; Liver; Measurement; Mediating; Methionine; Methionine Metabolism Pathway; Methylation; Methyltransferase; Modeling; Mus; Pathogenesis; Pathway interactions; Prevention; Preventive; Promoter Regions; Proteins; Regimen; Regulation; Regulator Genes; Role; S-Adenosylhomocysteine; S-Adenosylmethionine; Specimen; Steatohepatitis; Supplementation; Testing; Transcript; alcohol abuse therapy; alcohol effect; base; bisulfite; chromatin immunoprecipitation; fatty acid oxidation; feeding; histone methyltransferase; histone modification; inhibitor/antagonist; lipid biosynthesis; mRNA Expression; mouse model; nutrition; prevent; problem drinker; protein expression

DESCRIPTION (provided by applicant): The overall objective of this 2-year R03 proposal is to prove the hypothesis that the pathogenesis of alcoholic steatohepatitis (ASH) is mediated by epigenetic changes in the methylation of regulatory genes that result from the induction of aberrant hepatic methionine metabolism by exposure to ethanol. The study will use the cystathionine beta synthase (CbS) deficient mouse model of aberrant methionine metabolism in which wildtype (+/+) and heterozygous (+/-) mice with be fed control or ethanol containing diets that will or will not be supplemented with the methyl donor betaine over 4 weeks. Livers will be used for graded histopathology and measurements of methionine metabolites and of transcripts and protein levels of genes relevant to apoptosis and steatosis including those involved in lipogenesis, fatty acid oxidation, and lipid export. Subsequent epigenetic studies will include analyses of individual gene DNA methylation by DNA bisulfite sequencing and by methylation and acetylation of histone residues. Histone studies will include chromatin immunoprecipitation (ChIP) analysis of promoter regions of apoptosis and steatosis genes that have been found to be affected by ethanol feeding, genotype, and betaine supplementation. If the hypothesis is correct, the ethanol fed mouse groups will develop the histopathology of ASH, together with reductions in levels of the methyl donor S- adenosylmethionine (SAM), increase in the methyltransferase inhibitor S-adenosylhomocysteine (SAH), together with activation or suppression of genes involved in steatosis and their epigenetic regulations. The definitive proof of the hypothesis will be demonstration of the prevention of all changes by dietary supplementation with the methyl donor betaine. The significance of the project will be definition and proof of the mechanistic role of altered hepatic methionine metabolism and its epigenetic effects on the pathogenesis of ASH. Furthermore, the studies will point to the potential relevance of the findings to the treatment of ASH, based on correction of the epigenetic mechanisms that regulate its relevant genes. The studies will form the basis for a subsequent R01 application to extend the experimental approach to analysis of the expressions and epigenetic regulation of genes involved in other pathways of alcoholic liver injury and fibrosis in ASH and of relevant DNA and histone methyltransferases, acetylases and de-acetylases that are involved in the epigenetic regulation of these pathways.

描述（由申请人提供）：这项为期 2 年的 R03 提案的总体目标是证明以下假设：酒精性脂肪性肝炎 (ASH) 的发病机制是由调节基因甲基化的表观遗传变化介导的，而调节基因甲基化的表观遗传变化是由于暴露于乙醇诱导异常的肝脏蛋氨酸代谢而导致的。该研究将使用蛋氨酸代谢异常的胱硫醚β合酶（CbS）缺陷小鼠模型，其中野生型（+/+）和杂合（+/-）小鼠被喂食对照或含乙醇饮食，在4周内添加或不添加甲基供体甜菜碱。肝脏将用于分级组织病理学和测量蛋氨酸代谢物以及与细胞凋亡和脂肪变性相关的基因的转录物和蛋白质水平，包括那些涉及脂肪生成、脂肪酸氧化和脂质输出的基因。随后的表观遗传学研究将包括通过 DNA 亚硫酸氢盐测序以及组蛋白残基的甲基化和乙酰化来分析单个基因 DNA 甲基化。组蛋白研究将包括对凋亡和脂肪变性基因的启动子区域进行染色质免疫沉淀 (ChIP) 分析，这些区域已被发现受到乙醇喂养、基因型和甜菜碱补充的影响。如果假设正确，喂食乙醇的小鼠组将出现 ASH 的组织病理学，同时甲基供体 S-腺苷甲硫氨酸 (SAM) 水平降低，甲基转移酶抑制剂 S-腺苷高半胱氨酸 (SAH) 水平增加，同时激活或抑制参与脂肪变性及其表观遗传调控的基因。该假设的最终证据将是证明通过饮食补充甲基供体甜菜碱可以预防所有变化。该项目的意义在于定义和证明肝脏蛋氨酸代谢改变的机制作用及其对 ASH 发病机制的表观遗传影响。此外，基于对调节相关基因的表观遗传机制的纠正，这些研究将指出这些发现与 ASH 治疗的潜在相关性。这些研究将为后续的 R01 应用奠定基础，以扩展实验方法来分析参与酒精性肝损伤和 ASH 纤维化其他途径的基因的表达和表观遗传调控，以及参与这些途径的表观遗传调控的相关 DNA 和组蛋白甲基转移酶、乙酰化酶和去乙酰化酶。