Mechanisms of Liver Injury by Hepatitis C and Alcohol

丙型肝炎和酒精损伤肝的机制

• 批准号: 8441539
• 负责人: STEVEN A WEINMAN
• 金额: $ 48.04万
• 依托单位: UNIVERSITY OF KANSAS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-27 至 2017-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8441539
• 关键词: Acetylation; Affect; Affinity; Alcohol consumption; Alcoholic Liver Diseases; Alcohols; Antioxidants; Apoptosis; Behavior; Biological Assay; Blood capillaries; Boxing; Cell Cycle Regulation; Cell Nucleus; Cell Proliferation; Cell model; Chronic; Chronic Hepatitis C; Cirrhosis; Clinical; Complex; Cytosol; DNA Binding; Data; Development; Enzymes; Ethanol; Family; Fibrosis; Foundations; Genetic Transcription; Grant; Hepatic; Hepatitis C; Hepatitis C virus; Hepatocarcinogenesis; Hepatotoxicity; Human; Infection; Injury; Insulin; Isoelectric Focusing; Liver; Liver diseases; Measures; Methods; Mitochondria; Modification; Molecular; Nature; Neoplasms; Nuclear; Nuclear Export; Nuclear Import; Outcome; Oxidative Stress; Patients; Pattern; Phosphorylation; Post-Translational Protein Processing; Primary carcinoma of the liver cells; Process; Research; Resistance; Role; Sampling; Series; Testing; Therapeutic; Transferase; Tumor Suppressor Proteins; Ubiquitin-Conjugating Enzymes; Ubiquitination; Work; alcohol effect; alcohol exposure; alcohol response; alcohol sensitivity; biological adaptation to stress; capillary; cellular longevity; improved; insulin sensitivity; liver biopsy; liver injury; liver transplantation; loss of function; member; mouse model; nanoscale; novel; oxidant stress; prevent; programs; transcription factor; tumor; upstream kinase

DESCRIPTION (provided by applicant): The combination of Hepatitis C virus (HCV) infection and alcohol consumption produces a more severe liver disease than either condition alone with increased rates of both cirrhosis and hepatocellular carcinoma. We have recently discovered that the combination of HCV and alcohol causes a loss in the activity of the transcription factor FOXO3, a member of the forkhead box family of transcription factors that is responsible for oxidant stress resistance, control of cell proliferation, apoptosis, and insulin sensitivity. FOXO3 is also an established tumor suppressor molecule. Its cellular localization and transcriptional activity are regulated by a series of post translational modifications (PTMs) of the protein. Our preliminary data has shown that either HCV infection alone or alcohol exposure alone increases FOXO3 activity, but the combination of HCV and alcohol results in acetylation of FOXO3 and loss of its transcriptional activity. We also observed decreased FOXO3 activity in liver biopsies from chronic hepatitis C patients and abnormally localized FOXO3 in 85% of HCV-associated hepatocellular carcinomas. The central hypothesis of this proposal is that HCV causes changes in FOXO3 phosphorylation, acetylation and ubiquitination. These PTMs result from altered activity of upstream kinases, acetyl transferases, deacetylases, ubiquitin conjugating enzymes and deubiquitinases. The HCV/alcohol changes in FOXO3 and are responsible for enhanced sensitivity to alcohol and the loss of tumor suppressor activity in hepatocellular carcinoma. Therapeutic approaches targeting FOXO3 have the potential to improve HCV-alcohol associated liver injury and prevent the development of hepatocellular carcinoma. We will examine this hypothesis by three specific aims. They are: (1) to develop a novel nanoscale isoelectic focusing method to determine the nature and mechanism of HCV/ethanol-induced posttranslational modifications of FOXO3; (2) to determine why there is abnormal cytosolic accumulation of FOXO3 in hepatocarcinogenesis and whether this affects tumor behavior; and (3) to examine the role of HCV-induced FOXO3 acetylation in alcohol associated hepatotoxicity and test whether augmenting FOXO3 activity has potential to reduce liver injury. Methods to be employed include a novel isoelectric focusing assay for FOXO3 PTMs, examination of liver explants samples from patients undergoing liver transplantation for hepatocellular carcinoma, and cellular and mouse models of HCV-alcohol interactions. The hypotheses and approaches in this study are highly novel. Successful completion of these studies will identify the molecular changes in FOXO3 that result specifically from the HCV-alcohol interaction, determine how these contribute to cirrhosis and liver carcinogenesis, and use this information to establish the foundation for using FOXO3 manipulation as a therapeutic measure to improve outcome of patients with Hepatitis C and alcohol consumption.

描述（由申请人提供）：丙型肝炎病毒（HCV）感染和饮酒相结合会产生比单独任何一种情况更严重的肝脏疾病，并且肝硬化和肝细胞癌的发病率增加。我们最近发现，HCV 和酒精的结合会导致转录因子 FOXO3 的活性丧失，FOXO3 是转录因子叉头盒家族的成员，负责抗氧化应激、控制细胞增殖、细胞凋亡和胰岛素敏感性。 FOXO3 也是一种已确定的肿瘤抑制分子。其细胞定位和转录活性由蛋白质的一系列翻译后修饰 (PTM) 调节。我们的初步数据表明，单独的 HCV 感染或单独的酒精暴露都会增加 FOXO3 的活性，但 HCV 和酒精的结合会导致 FOXO3 乙酰化并丧失其转录活性。我们还观察到慢性丙型肝炎患者肝活检中 FOXO3 活性降低，并且 85% 的 HCV 相关肝细胞癌中 FOXO3 局部异常。该提议的中心假设是HCV导致FOXO3磷酸化、乙酰化和泛素化的变化。这些 PTM 是由上游激酶、乙酰转移酶、脱乙酰酶、泛素缀合酶和去泛素酶活性改变引起的。 FOXO3 中的 HCV/酒精发生变化，导致肝细胞癌中对酒精的敏感性增强以及肿瘤抑制活性的丧失。针对 FOXO3 的治疗方法有可能改善 HCV 酒精相关的肝损伤并预防肝细胞癌的发展。我们将通过三个具体目标来检验这一假设。它们是：（1）开发一种新型纳米级等电聚焦方法来确定HCV/乙醇诱导的FOXO3翻译后修饰的性质和机制； (2)确定肝癌发生过程中FOXO3在细胞质中异常积累的原因以及这是否影响肿瘤行为； (3) 检查 HCV 诱导的 FOXO3 乙酰化在酒精相关肝毒性中的作用，并测试增强 FOXO3 活性是否有可能减少肝损伤。所采用的方法包括针对 FOXO3 PTM 的新型等电聚焦测定、对接受肝细胞癌肝移植的患者的肝外植体样本进行检查，以及 HCV-酒精相互作用的细胞和小鼠模型。这项研究的假设和方法非常新颖。成功完成这些研究将确定 FOXO3 中由 HCV-酒精相互作用产生的分子变化，确定这些变化如何导致肝硬化和肝癌发生，并利用这些信息为使用 FOXO3 操作作为治疗措施奠定基础，以改善肝硬化和肝癌的发生。丙型肝炎患者和饮酒的结果。