Them1-Mediated Metabolic Regulation and Pathogenic Role in NAFLD

Them1 介导的 NAFLD 代谢调节和致病作用

• 批准号: 9103123
• 负责人: DAVID E. COHEN
• 金额: $ 10.3万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-05 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9103123
• 关键词: Acyl Coenzyme A; Address; Adipocytes; Adipose tissue; Binding; Biological; Brown Fat; Cell Culture System; Cells; Complex; Data; Diet; Disease; Energy Metabolism; Enzymes; Exhibits; Fatty Acids; Fatty Liver; Fatty acid glycerol esters; Gene Expression; Genes; Genetic Transcription; Glucose; Goals; Health; Hepatic; High Fat Diet; Homeostasis; Human; Individual; Inflammation; Inflammatory; Insulin Resistance; Ligands; Lipid Binding; Lipids; Liver; Liver diseases; Mass Spectrum Analysis; Mediating; Medication Management; Metabolic; Metabolism; Mission; Mitochondria; Molecular; Mouse Strains; Mus; Names; National Institute of Diabetes and Digestive and Kidney Diseases; Nonesterified Fatty Acids; Nutritional status; Obesity; Outcome Study; Overnutrition; Pathogenesis; Pathway interactions; Physiological; Play; Public Health; Recruitment Activity; Regulation; Research; Research Proposals; Resistance; Role; Structure; Temperature; Testing; Therapeutic; Thermogenesis; Transgenic Mice; Up-Regulation; X-Ray Crystallography; blood glucose regulation; design; endoplasmic reticulum stress; expectation; feeding; high throughput screening; improved; insight; macrophage; member; mitochondrial dysfunction; new therapeutic target; non-alcoholic fatty liver; novel; nutrient metabolism; overexpression; oxidation; public health relevance; research study; small molecule inhibitor; steroidogenic acute regulatory protein; tissue culture; trafficking

 DESCRIPTION (provided by applicant): Hepatic insulin resistance due to obesity is central to the pathogenesis of non-alcoholic fatty liver disease (NAFLD). This research proposal addresses the unanswered question of how molecular mechanisms that normally promote energy conservation contribute to NAFLD in obese individuals. The long-term goal of this research is to understand the regulatory relationships between cellular lipid molecules and metabolism, particularly as they present therapeutic opportunities. The objective of this research is to understand fundamental new mechanisms for the regulation of energy homeostasis and nutrient metabolism. The central hypothesis is that thioesterase superfamily member 1 (Them1) functions in brown adipose tissue (BAT) as a lipid-regulated fatty acyl-CoA thioesterase that controls intracellular fatty acid trafficking and that regulates the expression of thermogenic genes. In the setting of obesity, we postulate that upregulation of Them1 in liver and white adipose tissue promotes endoplasmic reticulum (ER) stress, mitochondrial dysfunction and inflammation due to the overproduction of free fatty acids. The rationale is that the mechanisms of Them1-mediated metabolic regulation should yield new insights into the pathogenesis of NAFLD. Guided by extensive preliminary data, the central hypothesis will be tested in three specific aims: 1) To determine the mechanisms whereby Them1 limits energy expenditure in BAT; 2) To demonstrate a primary pathogenic role for Them1 in NAFLD; and 3) To elucidate molecular regulation of Them1 activity by the lipid-binding steroidogenic acute regulatory protein-related lipid transfer (START) domain. In Aim 1, recently developed Them1-/- mice and cultured brown adipocytes will be used to test the hypothesis that Them1 in BAT limits access of fatty acids to mitochondria and reduces the expression of thermogenic genes. Aim 2 will leverage newly created transgenic mice, as well as cell culture systems to explore whether Them1 contributes directly to hepatic steatosis and insulin resistance. Mice with liver-specific overexpression will be used to establish the role of Them1 in promoting hepatic ER stress, mitochondrial dysfunction and inflammation. Mice with adipose-specific overexpression will reveal the contributions of Them1 to inflammation within white adipose tissue and to hepatic steatosis. Aim 3 will determine the lipid ligand(s) of the Them1 START domain by mass spectrometry. X-ray crystallography will be used to determine the structure of Them1 in complex with its ligands, the relationship among functional domains and the influence of lipid binding on enzymatic activity. High throughput screening will identity small molecule inhibitors, which should facilitate structure-function studies and help delineate the biological roles of Them1. Overall, this proposal will elucidate Them1-mediated metabolic regulation, which is significant because mechanisms that conserve energy in health may promote disease under conditions of overnutrition. These studies are expected to identify new therapeutic targets for the management of NAFLD.

 描述（由适用提供）：肥胖引起的肝胰岛素抵抗对于非酒精性脂肪肝病（NAFLD）的发病机理至关重要。这项研究提案解决了一个未解决的问题，即通常如何促进肥胖个体的NAFLD的分子机制如何促进NAFLD。这项研究的长期目标是了解细胞脂质分子和代谢之间的调节关系，尤其是在它们呈现治疗机会时。这项研究的目的是了解调节能量稳态和营养代谢的基本新机制。中心假设是硫酯酶超家族成员1（them1）在棕色脂肪组织（BAT）中起作用，作为脂质调节的脂肪酰基酰辅酶A硫酯酶，控制细胞内脂肪酸的运输，并调节热基因的表达。在肥胖症的情况下，我们假设肝脏和白脂肪组织中它们的上调1会促进内质网应激（ER）应激，线粒体功能障碍和由于游离脂肪酸的过度产生而引起的炎症。理由是它们的机制1介导的代谢调节应产生对NAFLD发病机理的新见解。在广泛的初步数据的指导下，将以三个特定的目的测试中心假设：1）确定将其1限制蝙蝠的能量消耗的机制； 2）在NAFLD中证明了它们的主要致病作用； 3）通过脂质结合类固醇激素急性调节蛋白相关脂质转移（Start）结构域来阐明它们1的分子调节。在AIM 1中，最近开发的它们1 - / - 小鼠和培养的棕色脂肪细胞将用于检验以下假设：蝙蝠中的它们1限制了脂肪酸进入线粒体并降低热基因的表达。 AIM 2将利用新创建的转基因小鼠，以及细胞培养系统来探索它们1是否直接促进肝脂肪变性和胰岛素抵抗。具有特异性过表达的小鼠将用于确定它们1在促进肝ER应激，线粒体功能障碍和炎症中的作用。具有脂肪特异性过表达的小鼠将揭示它们1对白脂肪组织内炎症和肝脂肪变性的贡献。 AIM 3将通过质谱法确定them1启动结构域的脂质配体。 X射线晶体学将用于确定与配体的复合物，功能域之间的关系以及脂质结合对酶活性的影响。高吞吐量筛选将识别小分子抑制剂，这应该促进结构功能研究并帮助描述它们的生物学作用1。总体而言，该提案将阐明它们1介导的代谢调节，这很重要，因为保存健康能量的机制可能会在营养不良的条件下促进疾病。这些研究有望确定NAFLD管理的新治疗靶标。