Regulation of energy homeostasis and adiposity by a Golgi-associated PARP enzyme

高尔基体相关 PARP 酶对能量稳态和肥胖的调节

基本信息

批准号：
8397552
负责人：
NAI-WEN CHI
金额：
--
依托单位：
VA SAN DIEGO HEALTHCARE SYSTEM
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-10-01 至 2013-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8397552
关键词：
ADP ribosylation Ablation Adipocytes Adipose tissue Affect Biological Assay Brown Fat Catabolism Comorbidity Data Diet Eating Embryo Energy Intake Energy Metabolism Enzymes Fatty Acids Fatty acid glycerol esters Fibroblasts Food deprivation (experimental)Foundations Future Genes Genetic Goals Golgi Apparatus Health Hepatic Homeostasis In Vitro Intake Intervention Kinetics Knock-out Light Lipids Liver Mediating Medical Metabolic Mitochondria Modeling Molecular Molecular Weight Mus Muscle Myocardial Infarction Non-Insulin-Dependent Diabetes Mellitus Obesity Organ Organelles Outcome Outcome Study Pathway interactions Peripheral Phenotype Physical activity Physiologic pulse Plasma Population Post-Translational Protein Processing Process Production Proteins Public Health Regulation Risk Factors Role Site Starvation Surveys Tankyrase Techniques Testing Tissues Triglycerides Up-Regulation Veterans Woman Work adipokines adiponectin base cold temperature combat cytokine fatty acid oxidation fight against in vivo innovation knock-down lipoprotein lipase men mouse model novel obesity treatment response stressor therapeutic target

项目摘要

Project Summary Many veterans suffer from obesity, an illness that results from a cumulative excess of energy intake over energy expenditure. To combat this health issue, it is important to identify novel regulators of energy homeostasis that are amenable to pharmacological intervention. Our long-term goal is to elucidate how energy homeostasis is regulated by tankyrase (TNKS), a Golgi-associated enzyme that modifies substrate proteins through poly-ADP-ribosylation. The aim of this application is to investigate the role of tankyrase in regulating energy expenditure with an emphasis on fuel substrate partitioning between organs as well as adiponectin secretion from adipocytes. To this end, we have used the gene- trapping technique in mice to create a tankyrase deficient (TNKS -/-) model. We found that TNKS -/- mice have increased energy expenditure, reduced adiposity, and greater food intake than wild-type controls. Intriguingly, their plasma levels of adiponectin, particularly the bioactive high molecular-weight form, are robustly increased. Consistent with the known effect of adiponectin, muscle in TNKS -/- mice shows an upregulation of genes that mediate the catabolism of triglycerides and fatty acids. On the other hand, liver in these mice shows an upregulation of genes that promote triglyceride release. Based on these and other observations, we hypothesize that the heightened energy expenditure in TNKS -/- mice entails increased hepatic secretion of triglycerides, which are channeled to the muscle for catabolism in response to hyperadiponectinemia. In this working model, the lipid flux from liver to muscle is at the expense of storage in adipose tissue, resulting in the lean phenotype of TNKS -/- mice despite a compensatory increase in food intake. To test our working hypothesis, Aim 1 will determine the extent to which TNKS deficiency increases the production and clearance of circulating triglycerides in vivo as well as the activity of muscle to hydrolyze triglycerides and oxidize fatty acids ex vivo. Aim 2 will evaluate the prediction that TNKS -/- mice, owing to increased energy expenditure, are protected from obesity and lipotoxicity when challenged with a high fat diet. Aim 3 will investigate the adipose-specific roles of TNKS in adiponectin secretion and energy homeostasis. Preliminary studies have shown that the hyperadiponectinemia of TNKS -/- mice is a post-transcriptional effect and can be recapitulated by knocking down TNKS in 3T3-L1 adipocytes. We will apply [35S] pulse-chase analysis to 3T3-L1 adipocytes to test the prediction that TNKS knockdown stabilizes adiponectin in the secretory pathway. We will also use the conditional knockout approach to determine the extent to which adipose-specific ablation of TNKS recapitulates the hyperadiponectinemia and other metabolic manifestations of TNKS -/- mice. The proposed studies are expected to shed light on the roles of TNKS in adiponectin secretion and energy homeostasis as well as the partitioning of fuel substrates between catabolism and storage. Outcomes from this application may provide the foundation for additional studies that validate TNKS as a pharmacological target for anti-obesity therapy.

项目概要许多退伍军人患有肥胖症，这是一种由于能量累积过多而导致的疾病摄入量超过能量消耗。为了解决这一健康问题，重要的是确定新的监管机构适合药物干预的能量稳态。我们的长期目标是阐明坦科聚合酶 (TNKS) 如何调节能量稳态，这是一种高尔基体相关酶，通过聚 ADP 核糖基化修饰底物蛋白。该应用程序的目的是调查端锚聚合酶在调节能量消耗中的作用，重点是燃料底物分配器官之间以及脂肪细胞分泌脂联素。为此，我们使用了基因—— 小鼠诱捕技术创建端锚聚合酶缺陷（TNKS -/-）模型。我们发现 TNKS -/- 小鼠的能量消耗增加，肥胖减少，并且食物摄入量高于野生型对照。有趣的是，他们的血浆脂联素水平，尤其是生物活性高分子量形式，大幅增加。与已知效果一致 TNKS -/- 小鼠的肌肉脂联素显示介导脂联素分解代谢的基因上调甘油三酯和脂肪酸。另一方面，这些小鼠的肝脏显示出基因的上调，这些基因促进甘油三酯的释放。基于这些和其他观察，我们假设 TNKS -/- 小鼠能量消耗增加导致肝脏甘油三酯分泌增加，它们被引导至肌肉进行分解代谢，以应对高脂联素血症。在这次工作中模型中，从肝脏到肌肉的脂质流动是以脂肪组织中的储存为代价的，从而导致尽管食物摄入量补偿性增加，但 TNKS -/- 小鼠的瘦表型。为了检验我们的工作假设，目标 1 将确定 TNKS 缺陷的程度增加体内循环甘油三酯的产生和清除以及肌肉的活动离体水解甘油三酯并氧化脂肪酸。目标 2 将评估 TNKS -/- 的预测由于能量消耗增加，小鼠在以下情况下可以免受肥胖和脂毒性的影响：面临高脂肪饮食的挑战。目标 3 将研究 TNKS 在脂联素中的脂肪特异性作用分泌和能量稳态。初步研究表明，高脂联素血症 TNKS -/- 小鼠是一种转录后效应，可以通过敲低 3T3-L1 中的 TNKS 来重现脂肪细胞。我们将对 3T3-L1 脂肪细胞应用 [35S] 脉冲追踪分析来测试以下预测： TNKS 敲低可稳定脂联素在分泌途径中的稳定性。我们还将使用条件敲除方法以确定 TNKS 的脂肪特异性消融在多大程度上重现了 TNKS -/- 小鼠的高脂联素血症和其他代谢表现。拟议的研究有望揭示 TNKS 在脂联素分泌中的作用和能量稳态以及燃料底物在分解代谢和储存之间的分配。该应用程序的结果可能为验证 TNKS 的其他研究奠定基础抗肥胖治疗的药理学靶点。