Mitochondrial Dysfunction and Adipose Insulin Resistance

线粒体功能障碍和脂肪胰岛素抵抗

• 批准号: 7893525
• 负责人: David A Bernlohr
• 金额: $ 37.41万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7893525
• 关键词: Adipocytes; Adipose tissue; Animal Model; Animals; Antioxidants; Biology; Cardiovascular Diseases; Cell Culture Techniques; Complex; Development; Diet; Disease; Disease model; Down-Regulation; Electron Transport; Enzymes; Etiology; Event; Fatty acid glycerol esters; Genetic Determinism; Genomics; Hormonal; Human; Human Biology; Hydrogen Peroxide; Hydroxyl Radical; Hypertension; Individual; Insulin; Insulin Resistance; Laboratories; Laboratory Study; Lead; Link; Lipids; MAPK14 gene; Metabolic; Metabolic Diseases; Metabolism; Minnesota; Mitochondria; Mitochondrial Proteins; Modeling; Modification; Molecular; N-terminal; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Oxidative Phosphorylation; Oxidative Stress; Pathway interactions; Phosphotransferases; Process; Production; Proteins; Proteomics; Reactive Oxygen Species; Reporting; Risk Factors; Role; Signal Transduction; Staging; Sum; Superoxides; System; Systems Biology; Technology; Testing; Thioredoxin; Thioredoxin-2; Transgenic Mice; Tumor Necrosis Factor-alpha; Tumor Necrosis Factors; Universities; Work; c JUN kinase; combat; gain of function; glutathione transferase A4; insight; insulin sensitivity; metabolomics; mitochondrial dysfunction; novel; oxidation; public health relevance

DESCRIPTION (provided by applicant): A variety of animal, cell culture and molecular studies have correlated increased oxidative stress and the accumulation of reactive oxygen species (ROS) such as superoxide anion and hydroxyl radicals to type 2 diabetes. While appreciated for years, it was unclear if oxidative stress / ROS was a casual or causal factor in the etiology of the disease. However, more recent work utilizing a variety of loss and gain of function analyses have indicated that oxidative stress is causally linked to insulin resistance but that the molecular mechanisms remain obscure. This application will profile new and compelling findings from our laboratories using animal and cell culture models that establish a molecular linkage between the antioxidant defense system in adipose cells with mitochondrial function, oxidative phosphorylation, signal transduction and the development of insulin resistance. We present a novel hypothesis supported by preliminary studies from genomic, proteomic, metabolomic and molecular analyses that point toward the covalent modification of mitochondrial proteins with bioactive lipids and the oxidation of mitochondrial thioredoxin as central to the process. Initiating this oxidative stress challenge are new findings that describe the tumor necrosis factor 1 (TNF1) dependent down regulation of glutathione S-transferase A4 setting the stage for a molecular cascade of events that activates the c-JUN NH2-terminal kinase (JNK), an established regulator of insulin sensitivity. Moreover, we present new findings that demonstrate that the down regulation of GSTA4 is not merely a process observed in animal models of insulin resistance but also occurs selectively in obese, insulin resistant, but not obese, insulin sensitive humans thereby providing a molecular differentiation between obesity and insulin resistance. This application builds on recent evidence obtained in the Bernlohr, Griffin and Arriaga laboratories that functionally links oxidative stress to insulin resistance. These studies in sum lead to our central hypothesis: decreased expression of GSTA4 in adipocytes leads to increased carbonylation of multiple protein targets. Carbonylation in turn initiates a cascade of molecular events leading to mitochondrial dysfunction and ROS production. ROS production leads to the oxidation of Thioredoxin 2 (Trx2) and the activation of Trx2-ASK1-JNK/p38 signaling system contributing to insulin resistance. To test this hypothesis, the following four specific aims are proposed: Specific Aim 1. Evaluate mitochondrial protein carbonylation and identify target proteins. Specific Aim 2. Assess ROS production and mitochondrial electron transport system in cell culture and animal models. Specific Aim 3. Develop and characterize aP2-HA-GSTA4 transgenic mice maintained on low and high fat diets. Specific Aim 4. Characterize cellular metabolism and the Trx2-ASK1-JNK pathway in animal and cell culture models. PUBLIC HEALTH RELEVANCE: A variety of animal, cell culture and molecular studies have correlated increased oxidative stress and the accumulation of reactive oxygen species (ROS) to type 2 diabetes. While appreciated for years, it was unclear if oxidative stress / ROS was a casual or causal factor in the etiology of the disease. This application will profile new and compelling findings from our laboratories using animal and cell culture models that establish a molecular linkage between the antioxidant defense system in adipose cells with mitochondrial function, oxidative phosphorylation, signal transduction and the development of insulin resistance. We present new findings that demonstrate that the down regulation of GSTA4 is not merely a process observed in animal models of insulin resistance but also occurs selectively in obese, insulin resistant, but not obese, insulin sensitive humans thereby providing a molecular differentiation between obesity and insulin resistance. If the hypothesis is proven to be correct, the study would be immediately translatable to human biology and afford a new view of how type 2 diabetes may be combated.

描述（由申请人提供）：多种动物，细胞培养和分子研究已将增加的氧化应激和活性氧（ROS）的积累，例如超氧化物阴离子和羟基自由基与2型糖尿病。虽然多年来被人们赞赏，但尚不清楚氧化应激 / ROS是否是该疾病病因的休闲因素或因果因素。但是，使用各种损失和功能分析增益的最新工作表明，氧化应激与胰岛素抵抗有因果关系，但分子机制仍然晦涩难懂。该应用将使用动物和细胞培养模型来介绍我们实验室的新发现，这些模型在具有线粒体功能，氧化磷酸化，信号转导和胰岛素抵抗的发展的脂肪细胞中建立分子连接。我们提出了一个新的假设，该假设得到了基因组，蛋白质组学，代谢组和分子分析的初步研究的支持，该研究表明，线粒体蛋白与生物活性脂质的共价修饰以及线粒体硫氧蛋白的氧化为中心。引发这种氧化应激挑战的是新发现，描述了肿瘤坏死因子1（TNF1）依赖于调节谷胱甘肽S-转移酶A4的调节，为激活C-Jun NH2末端激酶（JNK）的分子级联奠定了阶段，该事件的固定调节器，固定的胰岛素助理。此外，我们提出了新的发现，这些发现表明，GSTA4的下调不仅是胰岛素抵抗动物模型中观察到的过程，而且在肥胖，胰岛素抵抗性，但不是肥胖的胰岛素敏感人群中选择性地发生，从而提供了肥胖和胰岛素抵抗之间的分子差异。该应用基于在Bernlohr，Griffin和Arriaga实验室中获得的最新证据，该证据在功能上将氧化应激与胰岛素抵抗联系起来。这些研究总和导致了我们的中心假设：脂肪细胞中GSTA4表达的降低导致多种蛋白质靶标的羰基化增加。羰基化反过来启动了一系列分子事件，导致线粒体功能障碍和ROS产生。 ROS产生导致硫氧还蛋白2（TRX2）的氧化和TRX2-ASK1-JNK/p38信号系统的激活，这有助于胰岛素抵抗。为了检验这一假设，提出了以下四个特定目的：特定目标1。评估线粒体蛋白羰基化并鉴定靶蛋白。特定目标2。在细胞培养和动物模型中评估ROS产生和线粒体电子传输系统。特定目标3。发展并表征维持低脂饮食和高脂饮食的AP2-HA-GSTA4转基因小鼠。特定目的4。在动物和细胞培养模型中表征细胞代谢和TRX2-ass1-JNK途径。 公共卫生相关性：各种动物，细胞培养和分子研究已将增加的氧化应激与活性氧（ROS）的积累与2型糖尿病有关。虽然多年来被人们赞赏，但尚不清楚氧化应激 / ROS是否是该疾病病因的休闲因素或因果因素。该应用将使用动物和细胞培养模型来介绍我们实验室的新发现，这些模型在具有线粒体功能，氧化磷酸化，信号转导和胰岛素抵抗的发展的脂肪细胞中建立分子连接。我们提出了新的发现，这些发现表明，GSTA4的下调不仅是在胰岛素抵抗的动物模型中观察到的过程，而且在肥胖，胰岛素耐药性，但不是肥胖的胰岛素敏感人群中选择性地发生，从而提供了肥胖和胰岛素抵抗之间的分子差异。如果该假设被证明是正确的，那么该研究将立即转化为人类生物学，并提供对2型糖尿病如何应对的新观点。