REGULATION OF MYOCARDIAL PHOSPHOLIPASES AND LIPASES IN DIABETIC MYOCARDIUM

项目摘要/摘要 糖尿病心肌病是一种复杂的疾病，由长期和过度使用脂肪酸引起 由于缺乏胰岛素信号和葡萄糖摄取，糖尿病心肌的燃料收缩功能 利用率。糖尿病心肌中几乎唯一使用脂肪酸作为燃料导致了广泛的代谢 导致膜结构和功能发生多种有害变化的调节失调。在.期间 目前的授予间隔，我们已经利用我们开发的使能质谱学技术来识别 糖尿病心肌中过多的新信号分子，我们假设这些分子对糖尿病的发生有重要作用。 糖尿病心肌中的生物能量低效和适应不良信号。我们认为这些新的信号 分子导致患有急性冠脉综合征的糖尿病患者死亡率增加 到心肌梗塞(MI)。此外，这些信号通路的病理改变的后果是 糖尿病心肌梗死后5年预后差的原因 导致血流动力学损害的改变，并促进线粒体功能障碍 糖尿病心肌病。脂质在细胞功能中起着多效性作用，包括在细胞中产生能量的底物 心肌。糖尿病心肌病的一个主要方面是脂质的不适应和功能失调。 代谢和利用，从而导致有毒信号分子的产生。之前，通过 通过遗传学、药理学和化学生物学的方法，我们已经确定了三种主要的磷脂酶和 心肌中的脂肪酶iPLA2？(PNPLA9)、iPLA2γ(PNPLA8)和iPLA2ζ(PNPLA2；ATGL)可能作为 心肌血流动力学功能障碍、电生理改变和适应不良的主要介体 糖尿病心肌重塑。最近，我们证实了iPLA2γ及其下游信号转导 代谢物启动了一条转化的信号通路，这可能是许多多种有害物质的基础 糖尿病心肌组织有明显改变。因此，在具体目标1中，我们将使用我们的使能套件质量 光谱技术来鉴定由这种物质产生的新的信号分子的类型和数量 并通过系统生物学方法确定它们的功能，以确定它们在启动过程中的特定角色 和糖尿病心肌病的传播。在具体目标2中，我们确定了一种新的激活机制 IPLA2？因此，我们将确定激活的iPLA2？在调节非适应性生产中的作用 糖尿病心肌和糖尿病心肌中的信号代谢产物呈缺血状态。在具体目标3中，我们 将在糖尿病心肌中追求甘油三酯分子物种的戏剧性变化，在被 IPLA2ζ(PNPLA2；ATGL)可能促进糖尿病心肌细胞信号转导功能紊乱。总的来说，这些研究 是一种多学科协同的方法来确定介导糖尿病心肌病的化学机制 使用三种高度相关的糖尿病动物模型和遗传功能丧失的小鼠来提供一种 药物发现的快速通道方法和将重要的药理靶点转化为临床。

PROJECT SUMMARY/ABSTRACT Diabetic cardiomyopathy is a complex disorder that emanates from the chronic and excessive use of fatty acids to fuel contractile function in diabetic myocardium due to the lack of insulin signaling and glucose uptake and utilization. The nearly exclusive use of fatty acids for fuel in diabetic myocardium results in widespread metabolomic dysregulation that precipitates multiple deleterious alterations in membrane structure and function. During the current grant interval, we have utilized enabling mass spectrometric technologies we developed to identify a plethora of novel signaling molecules in diabetic myocardium which we hypothesize contribute significantly to the bioenergetic inefficiency and maladaptive signaling in diabetic myocardium. We propose that these novel signaling molecules contribute to the increased mortality of diabetic patients suffering from acute coronary syndromes leading to myocardial infarction (MI). Moreover, the consequences of these pathologic alterations in signaling pathways in diabetic myocardium lead to the poor 5 year prognosis of diabetic patients after MI and include bioenergetic alterations that precipitate hemodynamic compromise, and promote mitochondrial dysfunction characteristic of diabetic cardiomyopathy. Lipids serve pleiotropic roles in cell function including substrate for energy production in myocardium. A primary aspect of diabetic cardiomyopathy is the maladaptive and dysfunctional integration of lipid metabolism with utilization thereby resulting in the production of toxic signaling molecules. Previously, through genetic, pharmacologic and chemical biological approaches, we have identified three major phospholipases and lipases in myocardium iPLA2ß (PNPLA9), iPLA2γ (PNPLA8), and iPLA2ζ (PNPLA2; ATGL) that likely serve as principal mediators of myocardial hemodynamic dysfunction, electrophysiologic alterations and maladaptive remodeling in diabetic myocardium. Recently, we demonstrated that iPLA2γ and its downstream signaling metabolites initiate a transformative signaling pathway which likely underlies many of the multiple deleterious changes manifest in diabetic myocardium. Accordingly, in Specific Aim 1, we will use our enabling suites of mass spectrometric technologies to identify the types and amounts of novel signaling molecules produced by this pathway and identify their functions through a systems biology approach to define their specific roles in the initiation and propagation of diabetic cardiomyopathy. In Specific Aim 2, we have identified a novel mechanism activating iPLA2ß. Accordingly, we will identify the role of activated iPLA2ß in mediating the maladaptive production of signaling metabolites in diabetic myocardium and in diabetic myocardium rendered ischemic. In Specific Aim 3, we will pursue the dramatic changes in triglyceride molecular species in diabetic myocardium which, after hydrolysis by iPLA2ζ (PNPLA2; ATGL), likely promote dysfunctional signaling in diabetic myocardium. Collectively, these studies are a synergistic multidisciplinary approach to identify the chemical mechanisms mediating diabetic cardiomyopathy using three highly relevant animal models of diabetes in conjunction with genetic loss of function mice to provide a fast track approach to drug discovery and translation of prominent pharmacologic targets to the clinic.