Endothelial lipid droplet turnover and regulation of metabolic function

内皮脂滴周转和代谢功能的调节

基本信息

批准号：
10405064
负责人：
Nabil Boutagy
金额：
$ 15.29万
依托单位：
YALE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-08-01 至 2024-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10405064
关键词：
Acute Address Adipose tissue Aerobic Exercise Animals Biogenesis Biological Availability Biology Blood Blood Vessels Blood flow Buffers Cardiometabolic Disease Cardiovascular Diseases Cells Chronic Complex Cyclic GMP Diet Diglycerides Doctor of Philosophy Endoplasmic Reticulum Endothelial Cells Endothelium Enzymes Exercise Fatty acid glycerol esters Genetic Glucose Transporter Goals High Fat Diet Homeostasis Hydrolysis In Vitro Insulin Resistance Knock-out Knockout Mice Laboratories Link Lipase Lipids Maintenance Mediating Mentors Metabolic Metabolic Diseases Metabolic stress Metabolism Mitochondria Molecular Mouse Strains Mus Muscle Fibers Mutation NOS3 gene Nitric Oxide Non-Insulin-Dependent Diabetes Mellitus Nonesterified Fatty Acids Obesity Olive oil preparation Organelles Participant Pathway interactions Pharmacology Physiology Play Principal Investigator Protein Isoforms Proteins Regulation Reporting Research Risk Role Scientist Skeletal Muscle Supervision Tissues Training Training Programs Transferase Triglycerides Vascular Endothelium Work career development diacylglycerol O-acyltransferase diet-induced obesity endoplasmic reticulum stress endothelial dysfunction global health glucose uptake in vivo insight insulin sensitivity metabolic abnormality assessment mouse model response tool

项目摘要

Project Summary Accumulating evidence demonstrates that the vascular endothelium plays an important role in the regulation of metabolic homeostasis. In accordance, endothelial dysfunction contributes to metabolic derangements associated with obesity and insulin resistance. Our laboratory provided the first evidence that endothelial cells (ECs) have the capacity to form lipid droplets (LDs) in vivo and demonstrated that LD turnover (i.e., synthesis and degradation) is necessary for maintaining EC quiescence and function. Specifically, pharmacological inhibition of key enzymes in the LD synthesis pathway, diacylglycerol acetyl transferase (DGAT) 1 and 2, led to endoplasmic reticulum (ER) stress. Alternatively, endothelial specific deletion of adipose triglyceride lipase (ATGL), the rate-limiting enzyme in LD hydrolysis, led to a profound reduction in endothelial nitric oxide synthase (eNOS) protein levels and nitric oxide (NO) bioavailability in standard chow fed mice. Indeed, these vascular perturbations have been linked to derangements in whole-body metabolism, but the role of EC LD turnover as it relates to the control of vascular and metabolic function is unknown. Therefore, in this proposal, I will define the specific role of endothelial LD turnover in maintaining vascular and metabolic function during normal physiology, DIO and in response to acute and chronic exercise. To achieve these ends, I will generate inducible, endothelial specific ATGL knockout (iECKO), DGAT1-iECKO and DGAT2-iECKO mice as tools to dissect the molecular mechanisms by which LD turnover controls vascular and whole-body metabolic homeostasis. In aim 1, I will dissect the cellular mechanisms by which disruption in LD turnover leads to endothelial dysfunction under normal physiology and DIO via rigorous and meticulous molecular and metabolic characterization. In aim 2, I will decipher the importance of endothelial LD turnover in maintaining insulin sensitivity in normal physiology and DIO via comprehensive in vivo metabolic studies and ex vivo tissue analysis. Lastly, in aim 3, I will establish the role of endothelial LD turnover in the regulation of adaptations in response to an acute bout of exercise bout and chronic endurance training using a similar approach as aim 2. Collectively, these studies will address a heretofore unknown role of EC LD turnover in whole-body metabolism. Results from these studies will provide a better understanding of the interrelationship between vascular and metabolic function during normal physiology and in the setting of obesity and type II diabetes. In addition to these research aims, this proposal describes a five-year intensive mentored training program with the goal of developing the Principal Investigator (PI, Nabil Boutagy, Ph.D.) into an independent and high impact, scientist in the fields of vascular biology and metabolism under the supervision of his primary mentor, Dr. William Sessa, and co-mentor, Dr. Gerald Shulman. Furthermore, a team of world-class scientists has been assembled to provide oversight and guidance in achieving all aspects of the proposed research and the PI’s career development.

项目概要越来越多的证据表明，血管内皮在血管生成中发挥着重要作用。代谢稳态的调节因此，内皮功能障碍有助于代谢。我们的实验室提供了第一个证据表明，与肥胖和胰岛素抵抗相关的紊乱。内皮细胞 (EC) 具有在体内形成脂滴 (LD) 的能力，并证明 LD 周转（即合成和降解）对于维持 EC 静止和功能是必要的。药理抑制 LD 合成途径中的关键酶，二酰基甘油乙酰转移酶 (DGAT) 1和2，导致内质网（ER）应激或者内皮特异性脂肪缺失。甘油三酯脂肪酶 (ATGL) 是 LD 水解的限速酶，可导致内皮细胞活性显着降低。标准饲料喂养小鼠的一氧化氮合酶 (eNOS) 蛋白水平和一氧化氮 (NO) 生物利用度。事实上，这些血管扰动与全身代谢紊乱有关，但其作用 EC LD 转换与血管和代谢功能的控制有关，因此，在此方面尚不清楚。提案中，我将定义内皮LD周转率在维持血管和代谢方面的具体作用正常生理过程中的功能，DIO 以及对急性和慢性运动的反应来实现这些。结束后，我将生成可诱导的内皮特异性 ATGLout 敲除 (iECKO)、DGAT1-iECKO 和 DGAT2-iECKO 小鼠作为工具来剖析 LD 周转控制血管和全身的分子机制在目标 1 中，我将剖析导致 LD 周转破坏的细胞机制。通过严格细致的分子和代谢作用，在正常生理和DIO下修复内皮功能障碍在目标 2 中，我将解读内皮 LD 周转率在维持胰岛素方面的重要性。通过全面的体内代谢研究和离体组织分析，提高正常生理学和 DIO 的敏感性。最后，在目标 3 中，我将确定内皮 LD 周转率在适应调节中的作用，以响应使用与目标 2 类似的方法进行急性锻炼和长期耐力训练。总的来说，这些研究将解决 EC LD 周转率在全身代谢中的未知作用。这些研究将有助于更好地理解血管和代谢功能之间的相互关系在正常生理期间以及在肥胖和 II 型糖尿病的情况下除了这些研究目标之外，该提案描述了一个为期五年的强化指导培训计划，其目标是培养校长研究员（PI，Nabil Boutagy，博士）成为血管领域独立且具有高影响力的科学家在他的主要导师 William Sessa 博士和共同导师 Dr. William Sessa 的监督下进行生物学和新陈代谢研究。此外，还组建了一个由世界级科学家组成的团队来提供监督和指导。为实现拟议研究的各个方面和 PI 的职业发展提供指导。