The Role of Gm4951 in Nonalcoholic Fatty Liver Disease

Gm4951 在非酒精性脂肪肝中的作用

• 批准号: 10544345
• 负责人: Zhao Zhang
• 金额: $ 36.08万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10544345
• 关键词: Alleles; Body Weight; Characteristics; Cirrhosis; Coupling; Data; Development; Diet; Disease; Disease model; Energy Metabolism; Enzymes; Family; Fatty Liver; Future; Genes; Genetic; Genetic Screening; Genetic Transcription; Genetic Variation; Germ-Line Mutation; Goals; Guanosine Triphosphate Phosphohydrolases; Health; Hepatic; Hepatocyte; High Fat Diet; Homologous Gene; Human; Hydroxysteroids; In Vitro; Insulin; Insulin Resistance; Interferon Type II; Interferons; Knock-in Mouse; Knock-out; Knowledge; Lipids; Liver; Location; LoxP-flanked allele; Maps; Mass Spectrum Analysis; Meiosis; Metabolic; Missense Mutation; Molecular; Mus; Mutant Strains Mice; Mutation; Names; Obesity; Oxidoreductase; Pathogenesis; Pathway interactions; Pattern; Phenotype; Physiological; Prevalence; Primary carcinoma of the liver cells; Process; Promoter Regions; Proteins; Proteomics; Public Health; Regulation; Research; Role; Series; Severities; Slice; Testing; Time; Tissues; Transcriptional Regulation; Translating; Weight Gain; Work; adenoviral mediated; chronic liver disease; combat; dietary; disease phenotype; experimental study; fatty acid oxidation; glucose metabolism; inducible gene expression; insight; lipid biosynthesis; lipid metabolism; member; mouse model; mutant; new therapeutic target; non-alcoholic fatty liver disease; nonalcoholic steatohepatitis; novel strategies; novel therapeutic intervention; overexpression; oxidation; prevent; screening; transcription factor

PROJECT SUMMARY Nonalcoholic fatty liver disease (NAFLD) is becoming a global human health problem. Our long-term goal is to understand molecular mechanisms of NAFLD, and to translate this knowledge into novel therapeutic strategies. Due to the physiologic similarities between humans and mice, and the propensity of mice to develop a disease closely mimicking NAFLD when fed a high fat diet (HFD), mice have provided us with fundamental insights into NAFLD pathogenesis. In humans and mice, genetic variation influences the rate and severity of hepatosteatosis under a given set of environmental conditions. To identify genes that influence the process, we utilized unbiased forward genetic screening and highly automated meiotic mapping to identify mutations that cause NAFLD in mice sensitized by a HFD. Two semi-dominant missense alleles of predicted gene 4951 (Gm4951), named Oily and Carboniferous, were detected in this screen. As distinct from most NAFLD mutants that are associated with obesity, our preliminary data showed that Gm4951 deficient mice had dramatically increased hepatic lipid accumulation without a concomitant increase of body weight on a HFD. Gm4951 was highly expressed in hepatocytes. Knockout of Gm4951 increased lipid content and overexpression of Gm4951 decreased lipid content of primary hepatocytes in vitro, suggesting hepatocyte-intrinsic regulation of lipid content. Gm4951 knockout livers showed decreased expression of lipid oxidation genes. Mass spectrometry analysis of endogenous GM4951 interacting proteins revealed interaction with lipid droplet protein Hydroxysteroid 17β- dehydrogenase 13 (HSD17B13) and lipid oxidation enzymes. Moreover, the transcription of Gm4951 in hepatocytes was activated by interferon gamma (IFN-γ), which effectively decreased lipid content, much as when GM4951 was overexpressed. These results led to our central hypothesis that GM4951 is critical for promoting lipid oxidation, and limits hepatic lipid accumulation. To test this hypothesis, we propose to pursue three Specific Aims. Aim 1 will further investigate the development of NAFLD in GM4951 deficient mice. Aim 2 will determine the precise mechanistic role of GM4951 in regulating lipid metabolism. Aim 3 will study the transcriptional regulation of Gm4951, including the liver-specific expression pattern and the inducible expression by IFN-γ. Understanding how to activate GM4951 and what’s the human homolog of GM4951 would offer approaches to preventing or treating NAFLD. These will be studied in Aim 3 as well. The NAFLD phenotype caused by GM4951 deficiency is fundamentally distinct from the classic obesity-associated NAFLD mouse models. GM4951 is specifically expressed in the liver and operates there to limit lipid accumulation. Thus, finding ways to activate GM4951 will provide a new means of reducing hepatic lipid content. Completion of the proposed work will suggest new therapeutic targets to combat NAFLD.

项目摘要 非酒精性脂肪肝病（NAFLD）正在成为全球人类健康问题。我们的长期目标是 了解NAFLD的分子机制，并将这些知识转化为新颖的治疗策略。 由于人类和小鼠之间的生理相似性以及小鼠发展疾病的希望 当喂养高脂肪饮食（HFD）时，密切模仿NAFLD，为我们提供了对我们的基本见解 NAFLD发病机理。在人类和小鼠中，遗传变异会影响肝脏的率和严重程度 在给定的一组环境条件下。为了识别影响该过程的基因，我们利用了公正 正向遗传筛查和高度自动化的减数分裂映射，以识别导致小鼠NAFLD的突变 通过HFD敏感。预测基因4951（GM4951）的两个半主导地位等位基因，命名为Oily和Oily和 在此屏幕中检测到石炭纪。与大多数与之相关的NAFLD突变体不同 肥胖，我们的初步数据表明，GM4951缺乏小鼠大大增加了肝脂质 堆积而没有HFD上体重的同时增加。 GM4951在 肝细胞。 GM4951的敲除增加脂质含量和GM4951的过表达减少脂质 原发性肝细胞体外的含量，表明脂质含量的肝细胞内膜调节。 GM4951 敲除生命显示脂质氧化基因的表达降低。质谱分析 内源性GM4951相互作用蛋白显示与脂质液滴蛋白羟基固醇17β-的相互作用 脱氢酶13（HSD17B13）和脂质氧化酶。此外，GM4951的转录 通过干扰素伽马（IFN-γ）激活肝细胞，有效地降低了脂质含量，就像何时 GM4951过表达。这些结果导致我们的中心假设，即GM4951对于促进至关重要 脂质氧化，并限制肝脂质积累。为了检验这一假设，我们建议追求三个特定的特定 目标。 AIM 1将进一步研究GM4951缺乏小鼠中NAFLD的发展。 AIM 2将确定 GM4951在调节脂质代谢中的确切机械作用。 AIM 3将研究转录 GM4951的调节，包括IFN-γ的肝特异性表达模式和诱导表达。 了解如何激活GM4951，以及GM4951的人类同源物将提供什么方法 防止或治疗NAFLD。这些也将在AIM 3中研究。由GM4951引起的NAFLD表型 缺乏从根本上与经典的肥胖相关NAFLD小鼠模型不同。 GM4951是 在肝脏中特别表达并在此处进行以限制脂质积累。那，寻找激活的方法 GM4951将提供减少肝脂质含量的新含义。拟议工作的完成将 提出新的治疗靶标，以对抗NAFLD。