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 线粒体功能障碍定义为氧化能力和ATP合成降低。糖尿病是 并伴有包括高脂血症和高血糖症在内的多种全身性变化。一个关键的障碍 在确定导致糖尿病相关并发症发展的分子机制方面， 适当的体内模型的可用性，以独立地测试每一个。为了明确葡萄糖的作用 在线粒体功能的调节中，我们已经开发了一种小鼠模型，用于诱导 心肌细胞特异性表达的葡萄糖转运蛋白，GLUT 4。因此我们可以直接测试 心肌细胞的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一个 模型，由此在基础状态下增加的葡萄糖递送增强葡萄糖利用。与此形成鲜明对比的是， 在高血糖症的存在下增加的葡萄糖递送加速了线粒体的发展， 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。在这个提议中，我们将首先研究葡萄糖介导的 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）和氧化磷酸化（OXPHOS）基因表达的表观遗传控制 (Aim 2）。后一过程最近因其对“血糖记忆”的贡献而受到显著关注， 定义为前期血糖浓度对持续增加以下风险的影响： 糖尿病并发症与当前血糖控制水平无关。对于具体目标1，我们将确定 通过翻译后修饰O-连接GlcNAc酰化修饰的线粒体蛋白， 并开始探索葡萄糖输送对糖尿病患者的功能影响。 线粒体氧化能力和酶功能。目标2中概述的研究将确定以下方面的作用： 与OXPHOS基因表达变化相关的表观遗传修饰，这些表观遗传修饰由 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）和表观遗传学（组蛋白修饰和DNA甲基化）。这一额外培训将 为我提供知识和技能，以独立完成我的短期目标， 一个终身职位（R 00阶段），完成提案的目标和追求我的利益所必需的， 定义心脏功能障碍的分子机制。总的来说，这些研究的完成将 为葡萄糖在糖尿病发展中的机制基础提供了基本的见解 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.