TET1 in alcoholic liver disease progression

TET1 在酒精性肝病进展中的作用

• 批准号: 10399756
• 负责人: Chiung-Kuei Huang
• 金额: $ 17.57万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-01 至 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10399756
• 关键词: Affect; Albumins; Alcohol abuse; Alcohol consumption; Alcoholic Hepatitis; Alcoholic Liver Cirrhosis; Alcoholic Liver Diseases; Alcohols; Animals; Apoptosis; Apoptotic; Asthma; Azacitidine; Catalytic Domain; Cause of Death; Cell Death; Cessation of life; Chronic; Cirrhosis; DNA Damage; DNA Methylation; DNA Sequence; Data; Development; Diet; Dioxygenases; Disease; Disease Progression; Down-Regulation; Enterobacteria phage P1 Cre recombinase; Enzymes; Epigenetic Process; Ethanol; Family; Gene Expression; Generations; Genes; Hepatic; Hepatocyte; Human; In Vitro; Knock-out; Knockout Mice; Knowledge; Length; Link; Liquid substance; Liver; Liver Cirrhosis; Liver Fibrosis; LoxP-flanked allele; Malignant Neoplasms; Measures; Mediating; Modification; Molecular; Mus; Mutation; Necrosis; Outcome; Pathway interactions; Patients; Process; Rattus; Regulation; Rodent; Role; Sampling; Severities; Therapeutic; Tissues; Vascular Diseases; alcohol exposure; chronic alcohol ingestion; dietary control; effective therapy; improved; inhibitor/antagonist; knock-down; liver injury; member; oxidation; problem drinker; promoter; protein expression; response; small hairpin RNA; targeted treatment; therapeutic target; wound healing

Project Summary Chronic alcohol abuse has been linked to abnormal epigenetic modifications that affect the progression of alcoholic liver disease (ALD) by influencing factors in controlling cell death in hepatocytes. One such factor is 5-hydroxymethylcytosine (5hmC), but there is currently little information as to how chronic alcohol consumption affects 5hmC's regulation of cell death. Understanding how alcohol impacts 5hmC formation and consequently cell death pathways will potentially yield therapeutic approaches towards ALD. In our preliminary studies, we found that 5hmC expression is down-regulated in the livers of rats and mice fed with an ethanol diet as well as in human ALD tissues. We further examined the expression levels of enzymes involved in the generation of 5hmC, which include methylcytosine dioxygenase TET1, TET2, and TET3 in ALD samples. It was found that TET1 is significantly down-regulated in human and rodent ALD samples. We determined that using shRNA- TET1 to knockdown TET1 in human hepatocytes significantly suppressed 5hmC formation and promoted cell death as well as the pro-apoptotic gene, HRK. Intriguingly, the treatment of the DNA methylation inhibitor, 5- Azacytidine, could replace the impact of TET1 knockdown on hepatocyte cell death, further suggesting the importance of DNA methylation in TET1-mediated hepatocyte cell death. We then analyzed how TET1 down- regulation is involved in ALD progression by using TET1 knockout mice. It was found that knockout of TET1 substantially elicited liver fibrosis, which is consequently the outcome of wound-healing in chronic liver damage. Thus, our central hypothesis is that ethanol exposure increases hepatocyte cell death to promote ALD progression by suppressing TET1-mediated 5hmC epigenetic changes. Our long-term objective is to clarify the underlying mechanisms by which TET1 modulates ALD progression, and determine if TET1 is a potential therapeutic target in ALD. Two specific aims propose to evaluate our hypothesis. In aim 1, we will examine how TET1 modulates cell death pathways in ALD progression. We will investigate the enzymatic function of TET1 in regulating cell death pathways by using TET1 catalytic domain, full length TET1, TET1 catalytic domain dead mutation, and TET1 specific inhibitor. In aim 2, we will examine the role of TET1 in ALD progression. We will evaluate the impact of TET1 down-regulation on hepatocyte cell death in wild-type (WT) and TET1 knockout (KO) mice challenged with an alcoholic liquid diet. To further determine the hepatic specific TET1 role in ALD progression, we will generate liver specific TET1 knockout mice by using albumin promoter driven Cre mouse and floxed TET1 mouse. The results will significantly advance our knowledge of the mechanisms by which TET1 modulates hepatocyte cell death and improve our understanding of pathophysiological mechanisms underlying ALD progression. We also anticipate that it will have a broad impact on the understanding of TET1 expression and its relationship to hepatocyte function in general.

项目摘要 慢性酒精滥用与影响影响进展的异常表观遗传修饰有关 酒精性肝病（ALD）通过影响肝细胞细胞死亡的影响因素。一个因素是 5-羟基甲基胞嘧啶（5HMC），但目前几乎没有关于如何长期饮酒的信息 影响5HMC的细胞死亡调节。了解酒精如何影响5HMC形成，从而 细胞死亡途径可能会对ALD产生治疗方法。在我们的初步研究中，我们 发现5HMC表达在用乙醇饮食的大鼠和小鼠的肝脏中下调 在人类ALD组织中。我们进一步研究了与生成有关的酶的表达水平 5HMC，包括ALD样品中的甲基环胞嘧啶二加氧酶TET1，TET2和TET3。发现 在人和啮齿动物ALD样品中，TET1显着下调。我们确定使用shrna- TET1在人肝细胞中敲低TET1显着抑制了5HMC形成并促进细胞 死亡以及促凋亡基因HRK。有趣的是，DNA甲基化抑制剂的治疗，5- 偶氮丁胺可以取代TET1敲低对肝细胞死亡的影响，进一步表明 DNA甲基化在TET1介导的肝细胞死亡中的重要性。然后，我们分析了TET1如何下降 - 通过使用TET1基因敲除小鼠，调节涉及ALD进程。发现Tet1的淘汰赛 基本引起肝纤维化，因此，这是慢性肝损伤中伤口愈合的结果。 因此，我们的中心假设是乙醇暴露增加了肝细胞死亡以促进ALD 通过抑制TET1介导的5HMC表观遗传变化而进展。我们的长期目标是澄清 TET1调节ALD进展的基本机制，并确定TET1是否是潜在的 ALD的治疗靶标。有两个具体的目的提出评估我们的假设。在AIM 1中，我们将检查 TET1如何调节ALD进展中的细胞死亡途径。我们将研究 TET1通过使用TET1催化结构域，全长TET1，TET1催化来调节细胞死亡途径 结构域死亡突变和TET1特异性抑制剂。在AIM 2中，我们将研究TET1在ALD中的作用 进展。我们将评估TET1下调对野生型肝细胞死亡（WT）的影响 和TET1敲除（KO）小鼠受酒精液体饮食挑战。进一步确定肝特异性 TET1在ALD进展中的作用，我们将使用白蛋白启动子产生肝脏特异性TET1敲除小鼠 驱动的CRE小鼠和Floxed Tet1小鼠。结果将大大提高我们对 TET1调节肝细胞细胞死亡的机制并提高了我们对 ALD进展的基础病理生理机制。我们还预计它将有一个广泛的 一般而言，对TET1表达的理解及其与肝细胞功能的关系的影响。