Role of Beta-Catenin in the Molecular Pathogenesis of Alcoholic Steatohepatitis

描述(申请人提供)：酒精性肝病是美国发病率和死亡率的常见原因。酒精性脂肪性肝炎是该病的早期阶段，是可逆的，了解其分子发病机制对于确定该疾病的新治疗靶点至关重要。Wnt/β-catenin通路是一种细胞内信号通路，在正常肝脏的发育、生长和再生过程中起着重要作用。这项应用的主要目的是通过建立小鼠酒精性肝病模型，了解该通路在酒精性脂肪性肝炎分子发病机制中的作用。正在测试的中心假说是，Wnt信号通路中的关键角色--β-连环蛋白在酒精性脂肪性肝炎的发展中起着保护作用。为了验证这一假设，在特定的目标1中，将在体外和体内确定乙醇对Wnt/β-catenin信号的影响。乙醇处理的原代肝细胞培养物、枯否细胞培养物和肝癌细胞株将被用来研究Wnt信号在体外的变化。酒精喂养的小鼠将被用来研究体内Wnt信号的变化。在特定目标2中，将使用肝脏特异的b-catenin基因敲除小鼠来确定慢性酒精喂养对肝脏b-catenin丢失的影响。肝组织学、肝损伤标志物、氧化应激、肝纤维化、细胞因子谱和代谢基因表达的变化将在乙醇喂养的基因敲除小鼠的肝脏中表现出来。在具体目标3中，将研究酒精喂养对肝脏中表达稳定、突变形式的b-连环素的转基因小鼠肝脏的影响。这些研究将为酒精性脂肪性肝炎发生的分子事件提供新的见解。这份申请是为了申请为期五年的导师职业发展奖，研究将在匹兹堡大学萨达山·蒙加博士的主要指导下进行。该项目将为首席研究员Behari博士提供一个绝佳的机会，使其发展成为酒精相关肝病领域的独立研究员。

DESCRIPTION (provided by applicant): Alcoholic liver disease is a common cause for morbidity and mortality in the U.S. Alcoholic steatohepatitis, the early phase of the disease, is reversible and understanding its molecular pathogenesis is essential to identify new therapeutic targets for this disease. The Wnt/beta-catenin pathway is an intracellular signaling pathway that plays an important role in normal liver development, growth, and regeneration. The main aim of this application is to understand the role of this pathway in the molecular pathogenesis of alcohol-induced steatohepatitis using mouse models of alcoholic liver disease. The central hypothesis being tested is that the protein beta-catenin, a key player in the Wnt signaling pathway, plays a protective role in the development of alcoholic steatohepatitis. To test this hypothesis, in Specific Aim 1, the effects of ethanol on Wnt/beta-catenin signaling will be determined both in vitro and in vivo. Ethanol-treated primary hepatocyte cultures, Kupffer cell cultures, and hepatoma cell lines will be used to investigate changes in Wnt signaling in vitro. Ethanol-fed mice will be utilized to study changes in Wnt signaling in vivo. In Specific Aim 2, the effects of loss of b-catenin on the liver with chronic ethanol feeding will be determined using liver-specific b-catenin knockout mice. Liver histology, markers of liver injury, oxidative stress, hepatic fibrosis, cytokine profile, and alterations in the expression of metabolic genes will be characterized in the livers of ethanol-fed knockout mice. In Specific Aim 3, the effect of ethanol feeding on the liver in transgenic mice expressing a stable, mutated-form of b-catenin in the liver will be investigated. These studies will provide new insights into the molecular events underlying development of alcoholic steatohepatitis. This application is for a five-year Mentored Career Development Award and the studies will be carried out under the primary mentorship of Dr. Satdarshan Monga at the University of Pittsburgh. The project will provide an outstanding opportunity to the principal investigator, Dr. Behari, to develop into an independent investigator in the area of alcohol-related liver disease.