Molecular and Genetic Mechanisms of Fatty Liver Disease

 描述（由申请人提供）：非酒精性脂肪性肝病（NAFLD）是美国肝功能检查异常的最常见原因，可进展为肝硬化、肝细胞癌、需要肝移植和死亡。脂肪肝是一种与肥胖和代谢综合征相关的多基因疾病，其发病机制尚不清楚。人体研究表明，未折叠蛋白反应（UPR）在脂肪肝的发病机制中很重要; UPR的XBP 1 s通路的失调与NAFLD的进展形式（称为非酒精性脂肪性肝炎（NASH））相关。这项资助提案的总体目标是进一步确定Xbp 1 s在非酒精性脂肪肝发病机制中的作用，并确定可以为这种常见疾病提供治疗的新型调节因子和药理学药物。我们最近开发了肝细胞特异性缺失Xbp 1 s的小鼠，并将利用这些小鼠来确定Xbp 1 s信号传导对肝脏的作用和机制：A）使用高脂肪饮食的小鼠进行体内损伤;以及使用Huh 7细胞和原代肝细胞进行体外脂毒性（具体目标1）。随后，我们将采用定量性状基因座（QTL）分析和定位克隆喂食高脂肪饮食的小鼠，以确定新的基因和基因修饰剂，是重要的脂肪肝疾病的发病机制（具体目标2）。最后，我们将进行高通量化学筛选，以确定使用Huh-7细胞与XBP 1剪接荧光素酶报告基因构建体（特定目标3）增强肝脏XBP 1 s表达的化合物。该提案结合了分子生物学，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.