PNPLA3 in Susceptibility and Resistance to Fatty Liver Disease

PNPLA3 对脂肪肝疾病的易感性和抵抗力

基本信息

批准号：
10585702
负责人：
JONATHAN Charles COHEN
金额：
$ 57.56万
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 2027-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10585702
关键词：
Address Adipose tissue African African ancestry Alcoholic Fatty Liver Animal Model Autophagocytosis Binding Biochemical Biological Assay Body mass index CRISPR/Cas technology Cells Clinical Complex Development Diagnosis Disease Disputes Etiology European Fasting Fatty Liver Future Genes Genetic Transcription Glean Goals Grant Health Heart Hepatic High Prevalence Hispanic Populations Homeostasis Human Human Genetics Hydrolysis Impairment Individual Insulin Signaling Pathway Laboratories Lipase Lipids Liver Liver diseases Luciferases Maps Mediating Messenger RNA Metabolic Methods Molecular Monitor Mus Mutation Nutritional Obesity Pathogenesis Pathogenicity Pathway interactions Phospholipase Physiological Population Genetics Post-Transcriptional Regulation Predisposition Prevalence Prevention Prevention strategy Process Proteins Public Health Resistance Role Sampling Site Surveys System Technology Testing Therapeutic Tissues Translations Triglycerides Variant chronic liver disease cofactor combat fatty liver disease feeding gain of function gene discovery genetic approach genetic risk factor genetic variant in vivo insight mouse model multicatalytic endopeptidase complex mutant non-alcoholic fatty liver disease novel therapeutic intervention population based posttranscriptional prevent problem drinker protein expression protein protein interaction reconstitution recruit ubiquitin-protein ligase

项目摘要

Project Summary The goal of this project is to define the metabolic and molecular basis of fatty liver disease (FLD), a burgeoning health problem with few therapeutic options. Fatty liver disease has been a major focus of our laboratory since 2004, when we undertook the first survey of hepatic triglyceride (TG) content (HTGC) in a population-based sample of different ancestries, the Dallas Heart Study (DHS). Hepatic steatosis was found to be strongly influenced by ancestry (Hispanics>European>African) and adiposity, but varied widely even among individuals who were matched for ancestry and body mass index (BMI). We used human genetics to identify the first and most clinically impactful genetic risk factor variant for FLD: PNPLA3(148M). This variant confers susceptibility to the full spectrum of both alcoholic and nonalcoholic FLD. In the same study in which we identified PNPLA3(148M), we also identified another variant in PNPLA3, S453I, that is associated with reduced HTGC; this variant is present almost exclusively in individuals of African descent, the group with the lowest prevalence of FLD. These two variants together account for ~70% of ancestry-related differences in HTGC. Despite having made significant progress elucidating the pathogenic mechanism of the 148M variant, and having performed successful proof-of-concept studies in mice of potential therapeutic avenues to combat the effects of 148M, important questions regarding the pathobiology of the variant and how it is related to FLD remain unanswered or disputed. Accordingly, we will focus this application on three critical questions: 1) How does PNPLA3(148M) evade ubiquitylation and degradation? 2) How does the 148M variant impair TG hydrolysis? and 3) How does PNPLA3-S453I lower hepatic TG content and protect against FLD? Each of these questions constitutes a Specific Aim. We will take advantage of cutting edge technologies to overcome important limitations in prior methods used by us and others to address these questions. In AIM 1 we will use a CRISPR/Cas9 inactivation screen to identify the E3-ligase that ubiquitylates PNPLA3. In AIM 2 we will use a highly tunable system to control protein expression at the level of translation, and a sensitive, luciferase reconstitution assay to biochemically define the interactions among PNPLA3, ATGL, and ABHD5 at physiologically relevant concentrations in cells. In AIM 3 we will develop the first mouse model of PNPLA3(S453I) to determine how the variant lowers HTGC. Since the region of PNPLA3 spanning residue 453 is not present in mice, we will replace the mouse gene with a human mini-gene containing the S453I variant using CRISPR-Cas9 technology. These mice will be used to determine how this missense variant results in lower hepatic TG levels. These studies, when taken together, hold the promise of revealing new pathways and processes that can be therapeutically manipulated for the prevention and treatment of PNPLA3-related FLD.

项目概要该项目的目标是确定脂肪肝疾病 (FLD) 的代谢和分子基础，脂肪肝疾病是一种新兴疾病健康问题，治疗选择很少。脂肪肝疾病一直是我们实验室的主要研究对象 2004 年，我们首次对基于人群的肝甘油三酯 (TG) 含量 (HTGC) 进行了调查不同血统的样本，达拉斯心脏研究 (DHS)。发现肝脂肪变性严重受血统（西班牙裔>欧洲人>非洲人）和肥胖的影响，但即使在个体之间也存在很大差异血统和体重指数 (BMI) 相匹配的人。我们利用人类遗传学来识别第一个和 FLD 最具临床影响的遗传风险因素变异：PNPLA3(148M)。该变异体易感酒精性和非酒精性 FLD 的全谱。在我们确定的同一项研究中 PNPLA3(148M)，我们还鉴定了 PNPLA3 的另一个变体 S453I，它与 HTGC 减少相关；这种变异几乎只存在于非洲人后裔中，该群体的患病率最低的FLD。这两种变异共同解释了 HTGC 中约 70% 的血统相关差异。尽管在阐明 148M 变异的致病机制方面取得了重大进展，并且在小鼠身上进行了成功的概念验证研究，探讨了对抗这种疾病的潜在治疗途径 148M 的影响，有关该变异的病理学及其与 FLD 的关系的重要问题仍然存在没有答案或有争议。因此，我们将把这个应用程序集中在三个关键问题上：1）如何 PNPLA3(148M) 逃避泛素化和降解？ 2) 148M 变体如何损害 TG 水解？ 3) PNPLA3-S453I 如何降低肝脏 TG 含量并预防 FLD？这些问题中的每一个构成具体目标。我们将利用尖端技术来克服重要的限制我们和其他人以前使用的方法来解决这些问题。在 AIM 1 中，我们将使用 CRISPR/Cas9 灭活筛选以鉴定泛素化 PNPLA3 的 E3 连接酶。在 AIM 2 中，我们将使用高度可调的系统在翻译水平上控制蛋白质表达，以及灵敏的荧光素酶重建测定生化定义 PNPLA3、ATGL 和 ABHD5 之间生理相关的相互作用细胞内的浓度。在 AIM 3 中，我们将开发第一个 PNPLA3 小鼠模型（S453I），以确定如何变体降低 HTGC。由于 PNPLA3 跨越残基 453 的区域在小鼠中不存在，因此我们将替换使用 CRISPR-Cas9 技术将小鼠基因与含有 S453I 变体的人类小基因结合起来。这些小鼠将被用来确定这种错义变异如何导致肝脏 TG 水平降低。这些研究综合起来有望揭示新的途径和过程治疗操作用于预防和治疗 PNPLA3 相关的 FLD。

项目成果

期刊论文数量（4）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Contribution of a genetic risk score to ethnic differences in fatty liver disease.

DOI：
10.1111/liv.15322
发表时间：
2022-10
期刊：
LIVER INTERNATIONAL
影响因子：
6.7
作者：
Kubiliun, Maddie J.;Cohen, Jonathan C.;Hobbs, Helen H.;Kozlitina, Julia
通讯作者：
Kozlitina, Julia

Effect of donor HSD17B13 genotype on patient survival after liver transplant: a retrospective cohort study.

DOI：
10.1016/j.eclinm.2023.102350
发表时间：
2024-01
期刊：
ECLINICALMEDICINE
影响因子：
15.1
作者：
Kozlitina, Julia;Cohen, Naomi M.;Sturtevant, Drew;Cohen, Jonathan C.;Murphey-Half, Cathi;Saltarrelli, Jerome G.;Jindra, Peter;Askar, Medhat;Hwang, Christine S.;Vagefi, Parsia A.;Lacelle, Chantale;Hobbs, Helen H.;MacConmara, Malcolm P.
通讯作者：
MacConmara, Malcolm P.

Missense variant in insulin receptor (Y1355H) segregates in family with fatty liver disease.