Mechanisms of glucose mediated cardiac mitochondrial dysfunction

项目摘要 心力衰竭是糖尿病患者死亡的主要原因。心力衰竭的部分特征是 线粒体功能障碍的定义是氧化能力和ATP合成减少。糖尿病是 伴随着包括高脂血症和高血糖在内的一些全身变化。一个关键的障碍 在确定导致糖尿病相关并发症发生的分子机制方面 已经有了合适的体内模型来单独测试每种模型。要确定葡萄糖的作用 在向心脏传递线粒体功能的调节中，我们发展了一种小鼠模型，用于诱导 葡萄糖转运蛋白GLUT4的心肌细胞特异性表达。从而允许我们直接测试该角色 心肌细胞葡萄糖输送在健康和患病的心脏中发挥作用。我们的初步数据定义了 在基础状态下增加葡萄糖输送可提高葡萄糖利用率的模型。形成鲜明对比的是， 高血糖时葡萄糖输送增加可加速线粒体的发育 功能障碍。我研究的长期目标是确定控制线粒体的机制 心脏的代谢功能。在这项提案中，我们将从研究葡萄糖介导的作用开始 通过检测葡萄糖递送调节的线粒体翻译后修饰 线粒体蛋白(AIM 1)与氧化磷酸化基因表达的表观遗传调控 (目标2)。后一种过程最近因其对“血糖记忆”的贡献而受到极大关注， 定义为先前的血糖浓度对持续增加糖尿病风险的影响 糖尿病并发症与目前的血糖控制水平无关。对于特定的目标1，我们将确定 通过翻译后修饰O-连接的GlcN酰化修饰的线粒体蛋白， 它随着糖尿病的增加而增加，并开始探索葡萄糖输送在 线粒体氧化能力和酶功能。目标2中概述的研究将定义 与OXPHOS基因表达变化相关的表观遗传修饰 葡萄糖。该提案的初始K99阶段将促进蛋白质组学方面的培训(2D-PAGE和 质谱学)和表观遗传学(组蛋白修饰和DNA甲基化)。这项额外的培训将 为我提供知识和技能，使我能够独立地实现我的短期目标 终身职位(R00阶段)，完成提案目标和追求我的兴趣所必需的 界定心脏功能障碍的分子机制。总的来说，这些研究的完成将 为血糖在糖尿病发生发展中的机制基础提供基本见解 心肌病和线粒体功能障碍。

Project Summary Heart failure is a major cause of death in individuals with diabetes. Heart failure is characterized in part by mitochondrial dysfunction defined by decreased oxidative capacity and ATP synthesis. Diabetes is accompanied by a number of systemic changes including hyperlipidemia and hyperglycemia. A critical barrier in determining the molecular mechanisms that lead to the development of diabetes-related complications has been the availability of appropriate in vivo models to test each independently. To define the role of glucose delivery to the heart in the regulation of mitochondrial function we have developed a mouse model for inducible cardiomyocyte-specific expression of the glucose transporter, GLUT4. Thus allowing us to directly test the role that cardiomyocyte glucose delivery plays in the healthy and diseased heart. Our preliminary data define a model whereby increased glucose delivery in the basal state enhances glucose utilization. In stark contrast, increased glucose delivery in the presence of hyperglycemia accelerates the development of mitochondrial dysfunction. The long-term goal of my research is to determine the mechanisms controlling mitochondrial metabolic function in the heart. In this proposal, we will start by investigating the role of glucose-mediated mitochondrial regulation by examining glucose-delivery regulated post-translational modification of mitochondrial proteins (Aim 1) and epigenetic control of oxidative phosphorylation (OXPHOS) gene expression (Aim 2). The latter process has recently received significant attention for its contribution to "glycemic memory", defined as the impact that antecedent glucose concentrations have on persistently increasing the risk of diabetic complications independently of current levels of glycemic control. For Specific Aim 1, we will determine the mitochondrial proteins that are modified by the post-translational modification O-linked GlcNAcylation, which is increased with diabetes, and begin to explore the functional consequences of glucose delivery on mitochondrial oxidative capacity and enzymatic function. Studies outlined in Aim 2, will define the role of epigenetic modifications associated with changes in OXPHOS gene expression that are uniquely regulated by glucose. The initial K99 phase of this proposal will facilitate training in aspects of proteomics (2D-PAGE and mass spectroscopy) and epigenetics (histone modifications and DNA methylation). This additional training will provide me with the knowledge and skill set to independently carry out my immediate short-term goal of finding a tenure-track position (R00 phase), necessary to complete the proposal's aims and pursue my interests in defining molecular mechanisms of cardiac dysfunction. Collectively, the completion of these studies will provide fundamental insights into the mechanistic basis for glucose in the development of diabetic cardiomyopathy and mitochondrial dysfunction.