PGC-1 & Mitichondrial Dysfunction in Diabetes

PGC-1

• 批准号: 7825317
• 负责人: LAWRENCE J MANDARINO
• 金额: $ 51.3万
• 依托单位: ARIZONA STATE UNIVERSITY-TEMPE CAMPUS
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-02-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7825317
• 关键词: Accounting; Bioenergetics; Biogenesis; Biopsy; Complex; Creatine Kinase; Data; Development; Diabetes Mellitus; Electron Transport; Epidemic; Etiology; Euglycemic Clamping; Exercise; Functional disorder; Gene Expression; Genes; Glucose Clamp; Goals; Hand; Health Care Costs; Human; Immunoprecipitation; In Vitro; Individual; Infusion procedures; Insulin; Insulin Resistance; Lead; Link; Lipids; Mass Spectrum Analysis; Measurement; Messenger RNA; Mitochondria; Mitochondrial Proteins; Molecular; Muscle; Non-Insulin-Dependent Diabetes Mellitus; Nuclear; Obesity; Patients; Pattern; Phosphorylation; Pioglitazone; Post-Translational Protein Processing; Proteins; Proteomics; Regulation; Research; Resistance; Respiration; Respiratory physiology; Rest; Simulate; Site; Skeletal Muscle; Techniques; Testing; clinically significant; diabetic patient; improved; in vivo; insight; insulin sensitivity; mRNA Expression; mitochondrial dysfunction; novel; nrf1 protein; public health relevance; response

DESCRIPTION (provided by applicant): Our research in this project has focused on defining the changes in expression of nuclear encoded mitochondrial genes that predict changes in insulin sensitivity in skeletal muscle, with the goal of defining the molecular mechanisms underlying the connection between mitochondrial dysfunction and insulin resistance in skeletal muscle. We have found that lipid oversupply produced by a lipid infusion decreases mRNA expression of PGC-11, NRF-1, and nuclear encoded mitochondrial genes and induces insulin resistance. This was consistent with our original hypothesis that decreasing PGC-11 expression would result in lower expression of nuclear encoded mitochondrial genes and lead to mitochondrial dysfunction associated with insulin resistance. Additional studies showed a complex relationship between mitochondrial dysfunction, insulin sensitivity, and gene expression. Other data suggested that insulin resistant individuals could be exercise resistant. We also have shown that ATP synthase 2 is phosphorylated in vivo, and this may be regulated by insulin and altered in insulin resistance. Relatively little is known about changes in mitochondrial protein abundance or post-translational modification in insulin resistance, or their response to exercise or lipid oversupply. The overall goal of this proposal is to understand how underlying changes in regulation of mitochondrial respiration, protein abundance and phosphorylation contribute to mitochondrial dysfunction. To accomplish this goal, we will use glucose clamps, muscle biopsies, novel proteomics techniques for quantification of protein abundance changes, and in vitro mitochondrial respiration measurements using an energy clamp. We propose: 1. To determine whether mitochondrial isolated from insulin resistant human muscle have decreased respiration during conditions of increased energy demand simulated by a creatine kinase "energy clamp". 2. To determine how insulin resistance alters the pattern of abundance of mitochondrial proteins. 3. To determine how insulin resistance alters phosphorylation of proteins in the ETC. We will use immunoprecipitation and mass spectrometry analysis to quantify site-specific changes in phosphorylation of ETC proteins. 4. To determine whether insulin resistance is accompanied by "exercise resistance" with regard to mitochondrial biogenesis. 5. To determine whether experimental lipid oversupply decreases mitochondrial respiratory function. PUBLIC HEALTH RELEVANCE: Obesity and type 2 diabetes mellitus are increasing in epidemic proportion. Their complications account for up to forty percent of health care costs in the U.S. Despite this, the mechanisms responsible for their development remain unclear. This project will help to clarify these mechanisms on a molecular level. Given the clear evidence of a link to mitochondrial dysfunction in the etiology of obesity and insulin resistance, the studies are of high clinical significance and may provide useful new insights into the control of mitochondrial bioenergetics

描述(申请人提供)：我们在这个项目中的研究重点是确定预测骨骼肌胰岛素敏感性变化的核编码线粒体基因的表达变化，目的是确定骨骼肌线粒体功能障碍和胰岛素抵抗之间联系的分子机制。我们发现，由脂质输注产生的脂质供应过剩降低了PGC-11、NRF-1和核编码线粒体基因的mRNA表达，并诱导了胰岛素抵抗。这与我们最初的假设一致，即降低PGC-11的表达将导致核编码的线粒体基因表达降低，并导致与胰岛素抵抗相关的线粒体功能障碍。其他研究表明，线粒体功能障碍、胰岛素敏感性和基因表达之间存在复杂的关系。其他数据表明，胰岛素抵抗的人可能是运动抵抗者。我们还发现，ATP合成酶2在体内是磷酸化的，这可能受到胰岛素的调节，并在胰岛素抵抗中发生改变。对于线粒体蛋白丰度的变化或胰岛素抵抗的翻译后修饰，或者它们对运动或脂肪供应过剩的反应，人们知之甚少。这项建议的总体目标是了解线粒体呼吸、蛋白质丰度和磷酸化调节的潜在变化如何导致线粒体功能障碍。为了实现这一目标，我们将使用葡萄糖钳、肌肉活组织检查、量化蛋白质丰度变化的新蛋白质组学技术，以及使用能量钳进行体外线粒体呼吸测量。我们建议：1.确定从胰岛素抵抗的人肌肉中分离的线粒体在肌酸激酶“能量钳”模拟的能量需求增加的条件下是否降低了呼吸。2.确定胰岛素抵抗如何改变线粒体蛋白的丰度模式。3.确定胰岛素抵抗如何改变ETC中蛋白质的磷酸化。我们将使用免疫沉淀和质谱分析来量化ETC蛋白磷酸化的位点特异性变化。4.确定胰岛素抵抗是否伴随着线粒体生物发生的“运动抵抗”。5.确定实验性脂质供应过剩是否降低线粒体呼吸功能。公共卫生相关性：肥胖症和2型糖尿病的流行比例正在上升。他们的并发症占美国医疗费用的40%。尽管如此，导致他们发展的机制仍然不清楚。该项目将有助于在分子水平上阐明这些机制。鉴于有明确证据表明线粒体功能障碍与肥胖和胰岛素抵抗的病因有关，这些研究具有很高的临床意义，并可能为线粒体生物能量学的控制提供有用的新见解。