Role of Arginine Methylation in Alcohol Pathogenesis

项目总结 酒精性肝病是一大临床问题，其易感因素尚不清楚。它会显示已标记 疾病表型的变异性。只有大约15%的酗酒者会患上疾病，而85%的人似乎会 受保护，这表明大多数人都有对酒精的适应机制。精氨酸 甲基化是一种常见的翻译后修饰(PTM)，它直接和 更多是通过组蛋白精氨酸甲基化(表观遗传调控)。蛋白质精氨酸甲基转移酶1 PRMT1是细胞内约90%的精氨酸甲基化的主要酶。JMJD6是唯一 已知的精氨酸脱甲基酶 初步数据显示，酒精性肝病患者的PRMT1蛋白水平极低 与其他患者组比较，提示PRMT1可能参与了这些疾病的进展 病人。利用肝细胞特异性基因敲除小鼠模型，我们发现在酒精喂养的小鼠中存在PRMT1基因敲除 导致肝细胞死亡、脂肪变性、炎症和纤维化的急剧增加；以及血清的增加 ALT水平提示PRMT1对酒精性肝损伤有保护作用。PRMT1的此功能是 特异性的酒精，初步数据表明，它是由酒精诱导的去磷酸化的 PRMT1.因此，我们假设酒精诱导的PRMT1活性变化对肝脏是必要的。 对酒精的适应。本项目将具体检验这一假设，具体目标如下： 具体目的1.研究PRMT1介导酒精敏感性的机制。我们将研究非 组蛋白靶标和启动子精氨酸甲基化，并定义主要途径。具体目标2.界定 PRMT1磷酸化在酒精性肝损伤保护中的作用我们假设 去磷酸化形式对酒精引起的损伤具有特别的保护作用。抑制上游的蛋白激酶 这个病例是一种很有前途的治疗策略。具体目标3.确定精氨酸的作用 去甲基化酶JMJD6在酒精性肝损伤易感性中的作用JMJD6是另一个 很有希望的目标。抑制JMJD6可逆转PRMT1基因敲除小鼠的表型。我们会研究 这一调节机制。 拟议项目的结果将为人类精氨酸甲基化缺陷的性质提供新的见解。 酒精性肝病。它应该确定PRMT1和JMJD6是否是 肝细胞对酒精的适应，并确定主要靶点。该项目将为进一步发展奠定基础 研究了解患者的酒精敏感性，并探索潜在的治疗靶点。这个 最终目标是利用这些信息开发治疗酒精相关性肝病的临床策略。

PROJECT SUMMARY Alcoholic liver disease is a major clinical problem with unknown susceptibility factors. It displays marked variability in disease phenotype. Only about 15% of heavy drinkers develop disease while 85% appear to be protected, suggesting that there are mechanisms of adaptation to alcohol in majority of individuals. Arginine methylation is a common posttranslational modification (PTM) that regulates hundreds of proteins directly and many more via histone arginine methylation (epigenetic regulation). Protein arginine methyltransferase 1 (PRMT1) is the main enzyme responsible for about 90% of cellular arginine methylation. JMJD6 is the only known arginine demethylase Preliminary data indicate that patients with alcoholic liver disease have extremely low levels of PRMT1 protein compared other patient groups suggesting that PRMT1 might be involved in disease progression of these patients. Using hepatocyte specific knockout mouse model, we found that PRMT1 knockout in alcohol fed mice results in dramatic increase in hepatocyte death, steatosis, inflammation and fibrosis; and increased serum ALT levels suggesting that PRMT1 is protective against alcohol induced liver injury. This function of PRMT1 is specific to alcohol, and preliminary data suggests that it is mediated by alcohol induced dephosphorylation of PRMT1. We thus hypothesize that alcohol induced changes in PRMT1 activity are necessary for liver adaptation to alcohol. This project will specifically examine this hypothesis with the following specific aims: Specific Aim 1. To study the mechanism of PRMT1 mediated alcohol sensitivity. We will study non- histone targets and promoter arginine methylation and define the major pathways. Specific Aim 2. To define the role of PRMT1 phosphorylation in protection from alcohol induced liver injury. We hypothesize that dephosphorylated form is particularly protective from alcohol induced injury. Inhibiting the upstream kinase in this case is a promising future therapeutic strategy. Specific Aim 3. To define the role of arginine demethylation enzyme JMJD6 in susceptibility to alcohol induced liver injury. JMJD6 is another promising target. JMJD6 inhibition reverts the phenotype of PRMT1 knockout mice. We will study the mechanism of this regulation. Results of the proposed project will provide novel insights into the nature of the arginine methylation defects in alcoholic liver disease. It should determine whether PRMT1 and JMJD6 are essential regulators of the hepatocyte adaptation to alcohol and identify the primary targets. The project will set the stage for further studies to understand the alcohol susceptibility in patients and explore the potential targets for therapy. The ultimate goal is to use this information to develop clinical strategies to treat alcohol associated liver disease.