Molecular and Genetic Mechanisms of Fatty Liver Disease

 描述(申请人提供)：非酒精性脂肪性肝病(NAFLD)是美国肝功能检测异常的最常见原因，可发展为肝硬化、肝细胞癌、需要肝移植和死亡。脂肪肝是与肥胖和代谢综合征相关的多基因疾病，但其发病机制尚不清楚。人类研究表明，未折叠蛋白反应(UPR)在脂肪肝的发病机制中起重要作用；UPR的XBP1s通路失调与非酒精性脂肪性肝炎(NASH)的进展型NAFLD有关。这项赠款提案的总体目标是进一步确定Xbp1在非酒精性脂肪性肝病发病机制中的作用，并确定可以为这种常见疾病提供治疗的新的调节因子和药理学试剂。我们最近培育了肝细胞特异性缺失Xbp1s的小鼠，并将利用这些小鼠来确定Xbp1s信号在肝脏中的作用和机制：a)使用高脂饮食的小鼠体内损伤；以及使用Huh7细胞和原代肝细胞的体外脂毒性(特异性目标1)。随后，我们将对喂食高脂饮食的小鼠进行数量性状基因座(QTL)分析和位置克隆，以确定在脂肪性肝病发病机制中重要的新基因和基因修饰物(特定目标2)。最后，我们将进行高通量的化学筛选，以确定增强肝脏XBP1s表达的化合物使用具有XBP1剪接荧光素酶报告基因构建的Huh-7细胞(特定目标3)。这一建议结合了分子生物学、正向和反向遗传学以及高通量方法，以进一步确定脂肪性肝炎的发病机制，并开发非酒精性脂肪性肝病的治疗方法。

 DESCRIPTION (provided by applicant): Non-alcoholic fatty liver disease (NAFLD) is the most common cause of abnormal liver function tests in the United States, and it can progress to cirrhosis, hepatocellular carcinoma, need-for- liver transplantation and death. Fatty liver disorders are polygenic diseases that are associated with obesity and the metabolic syndrome, however, the pathogenesis remains poorly understood. Human studies demonstrate that the Unfolded Protein Response (UPR) is important in the pathogenesis of fatty liver; and dysregulation of the XBP1s pathway of the UPR is associated with the progressive form of NAFLD termed non-alcoholic steatohepatitis (NASH). The overall objectives of this grant proposal are to further determine the role of Xbp1s in the pathogenesis of non-alcoholic fatty liver disease and identify novel regulatory factors and pharmacologic agents that can provide therapies for this common disease. We have recently developed mice with a hepatocyte-specific deletion of Xbp1s and will utilize these mice to determine the role and mechanisms of Xbp1s signaling on hepatic: A) injury in vivo using mice fed High-Fat diets; and lipotoxicity in vitro usng Huh7 cells and primary hepatocytes (Specific Aim 1). We will subsequently employ Quantitative Trait Loci (QTL) analysis and positional cloning of mice fed a High-Fat diet to identify novel genes and gene modifiers that are important in the pathogenesis of fatty liver diseases (Specific Aim 2). Finally, we will perform a high-throughput chemical screen to identify compounds that enhance hepatic XBP1s expression using Huh-7 cells with a XBP1- splicing luciferase reporter gene construct (Specific Aim 3). This proposal combines molecular biology, forward and reverse genetics, and high-throughput approaches to further determine the pathogenesis of steatohepatitis and develop therapies for non-alcoholic fatty liver diseases.