Role of PNPLA3 in Fatty Liver Disease

PNPLA3 在脂肪肝疾病中的作用

基本信息

批准号：
8108191
负责人：
Helen Haskell Hobbs
金额：
$ 36.46万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-08-01 至 2014-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8108191
关键词：
Adipose tissue Adult Affect African American Alcoholic Liver Cirrhosis Alcoholic Liver Diseases Alcohols Alleles Animal Model Biochemistry Biological Biopsy Child Cirrhosis Cross-Sectional Studies DNA Sequence Diagnosis Disease Disease Progression Enzymes Family Fatty Liver Fibrosis Frequencies Genetic Genetic Variation Glean Goals Health Hepatic Hispanics Human Human Genetics Hydrolase Hydrolysis In Vitro Individual Inflammation Inflammatory Response Injury Injury to Liver Insulin Resistance Knock-in Mouse Link Lipase Lipids Liver Liver diseases Malignant neoplasm of liver Mass Spectrum Analysis Mediating Membrane Lipids Methods Missense Mutation Modeling Molecular Molecular Probes Mus Mutation Obesity Pathogenesis Pathology Phospholipase Physiological Physiology Predisposition Prevalence Process Proteins Recombinants Role Series Simulate Steatohepatitis Testing Therapeutic Therapeutic Intervention Transgenes Triglycerides United States Variant base comparative design enzyme activity enzyme substrate fatty acid metabolism gain of function genome-wide analysis human disease in vivo insight lipid metabolism mouse model non-alcoholic fatty liver novel strategies overexpression oxidation prevent reconstitution research study very low density lipoprotein triglyceride

Adipose tissue Adult Affect African American Alcoholic Liver Cirrhosis Alcoholic Liver Diseases Alcohols Alleles Animal Model Biochemistry Biological Biopsy Child Cirrhosis Cross-Sectional Studies DNA Sequence Diagnosis Disease Disease Progression Enzymes Family Fatty Liver Fibrosis Frequencies Genetic Genetic Variation Glean Goals Health Hepatic Hispanics Human Human Genetics Hydrolase Hydrolysis In Vitro Individual Inflammation Inflammatory Response Injury Injury to Liver Insulin Resistance Knock-in Mouse Link Lipase Lipids Liver Liver diseases Malignant neoplasm of liver Mass Spectrum Analysis Mediating Membrane Lipids Methods Missense Mutation Modeling Molecular Molecular Probes Mus Mutation Obesity Pathogenesis Pathology Phospholipase Physiological Physiology Predisposition Prevalence Process Proteins Recombinants Role Series Simulate Steatohepatitis Testing Therapeutic Therapeutic Intervention Transgenes Triglycerides United States Variant base comparative design enzyme activity enzyme substrate fatty acid metabolism gain of function genome-wide analysis human disease in vivo insight lipid metabolism mouse model non-alcoholic fatty liver novel strategies overexpression oxidation prevent reconstitution research study very low density lipoprotein triglyceride

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项目摘要

DESCRIPTION (provided by applicant): Nonalcoholic fatty liver disease (NAFLD) is a burgeoning health problem that affects one-third of adults and an increasing number of children in the U.S. The disease process begins with the accumulation of triglyceride (TG) in the liver (steatosis), which in some individuals elicits an inflammatory response (steatohepatitis) that can progress to cirrhosis, and possibly liver cancer. Although various factors (e.g., obesity, insulin resistance) are associated with NAFLD in cross-sectional studies, the pathogenesis of NAFLD remains poorly understood and therapeutic options are currently very limited. Our group has taken a genetic approach to identify causal factors that contribute to NAFLD. Recently, we identified a missense mutation (I148M) in patatin-like phospholipase domain-containing protein, PNPLA3 that is strongly associated with both hepatic TG content and hepatic injury. The variant is most common in Hispanics, the group with the greatest prevalence of hepatic steatosis and least common in African-Americans who have the lowest frequency of steatosis. Subsequent studies have confirmed our findings and showed that the PNPLA3-I148M variant is enriched in subjects with biopsy-proven steatohepatitis and with alcohol-related cirrhosis. Thus, PNPLA3 is implicated as a contributing factor in the full spectrum of NAFLD as well as alcoholic cirrhosis. Basic questions remain regarding the physiological role of PNPLA3 and how genetic variation in this enzyme promotes hepatic TG accumulation, inflammation and fibrosis. The overall goal of this application is to elucidate the role of PNPLA3 in fatty liver disease. To this end, we will use a combination of classical biochemistry and physiology plus state-of-the-art mass-spectrometry in mice with genetically-defined changes in PNPLA3 function to identify the substrates and products of the enzyme, the role in PNPLA3 in lipid metabolism and the molecular basis for its association with TG accumulation and liver damage. Two complementary approaches will be used to identify the biological substrate(s) of PNPLA3: i) a candidate substrate approach using purified enzyme (Aim 1a) and a comparative lipidomic approach in genetically- modified mice (Aim 1b) to identify lipids that are altered by changes in PNPLA3 activity. In Aims 2 we will use our mouse models to examine effects of PNPLA3-I148M on hepatic lipid metabolism. Aim 3 focuses on identifying molecular mechanisms by which PNPLA3-I148M promotes TG accumulation in the liver. Finally, in Aim 4 we will establish a mouse model in which to investigate the mechanisms by which PNPLA3 contributes to hepatic inflammation and fibrosis. By elucidating the biological role of PNPLA3 and the mechanisms by which the I148M mutation confers susceptibility to fatty liver disease, the experiments outlined in this proposal will provide new insight into the pathogenesis of a major human disease that continues to increase in prevalence. Our ultimate goal is to develop new approaches and strategies to diagnose, prevent and treat NAFLD. PUBLIC HEALTH RELEVANCE: Nonalcoholic fatty liver disease (NAFLD) is a burgeoning health problem that affects one-third of adults and an increasing number of children in the United States. Insights into the causes of NAFLD are urgently required since no therapeutic intervention has proven to be uniformly effective in this disease. We have used human genetic studies to identify a protein that contributes to fatty liver disease, and will exploit this finding to elucidate the underlying causes of the condition. Our ultimate goal will be to develop new approaches and strategies to diagnose, prevent and treat NAFLD.

DESCRIPTION (provided by applicant): Nonalcoholic fatty liver disease (NAFLD) is a burgeoning health problem that affects one-third of adults and an increasing number of children in the U.S. The disease process begins with the accumulation of triglyceride (TG) in the liver (steatosis), which in some individuals elicits an inflammatory response (steatohepatitis) that can progress to cirrhosis, and possibly liver cancer.尽管在横截面研究中，各种因素（例如肥胖，胰岛素抵抗）与NAFLD有关，但NAFLD的发病机理仍然鲜为人知，治疗选择目前非常有限。我们的小组采用了一种遗传方法来识别导致NAFLD的因果因素。最近，我们确定了含patatin的含磷脂酶结构蛋白PNPLA3的错义突变（I148M），与肝TG含量和肝损伤密切相关。该变体在西班牙裔中最常见，这是肝脂肪变性最高的群体，在脂肪变性频率最低的非裔美国人中最不常见。随后的研究证实了我们的发现，并表明PNPLA3-I148M变体富含活检证实的脂肪性肝炎和与酒精相关的肝硬化的受试者。因此，PNPLA3被认为是NAFLD和酒精性肝硬化的全部范围中的一个促成因素。关于PNPLA3的生理作用以及该酶中的遗传变异如何促进肝TG积累，炎症和纤维化的基本问题。该应用的总体目标是阐明PNPLA3在脂肪肝病中的作用。为此，我们将使用经典的生物化学和生理学以及在PNPLA3功能中具有遗传定义的变化的小鼠中的最先进的质谱法，以识别酶的底物和产物，在脂质代谢中的PNPLA3在PNPLA3中的作用，在脂质代谢中与TG累积和liver liver saggulation and the Mocullist and Islive and sockular and Islive and sockulation and liver and liver saskable and sockully and liver。将使用两种互补方法来识别PNPLA3的生物底物：i）使用纯化酶（AIM 1A）的候选底物方法和遗传修饰的小鼠（AIM 1B）中的比较脂肪组方法，以识别PNPLA3活性变化而改变的脂质。在AIMS 2中，我们将使用小鼠模型来检查PNPLA3-I148M对肝脂质代谢的影响。 AIM 3的重点是识别PNPLA3-I148M促进肝脏中TG积累的分子机制。最后，在AIM 4中，我们将建立一个小鼠模型，以研究PNPLA3有助于肝炎和纤维化的机制。通过阐明PNPLA3的生物学作用以及I148M突变赋予对脂肪肝病的易感性的机制，该提议中概述的实验将为主要人类疾病的发病机理提供新的见解，而这种发病率持续增加。我们的最终目标是制定新的方法和策略来诊断，预防和治疗NAFLD。公共卫生相关性：非酒精性脂肪肝疾病（NAFLD）是一个迅速发展的健康问题，影响了三分之一的成年人和越来越多的儿童。迫切需要对NAFLD的原因的见解，因为事实证明，没有治疗干预在该疾病中有效。我们已经使用人类遗传学研究来识别有助于脂肪肝病的蛋白质，并将利用这一发现以阐明该疾病的根本原因。我们的最终目标是制定新的方法和策略来诊断，预防和治疗NAFLD。