REGULATION OF MYOCARDIAL PHOSPHOLIPASES AND LIPASES IN DIABETIC MYOCARDIUM

项目总结/摘要 糖尿病性心肌病是一种复杂的疾病，它源于长期和过度使用脂肪酸， 由于缺乏胰岛素信号传导和葡萄糖摄取，糖尿病心肌中的燃料收缩功能， 利用率糖尿病心肌几乎完全使用脂肪酸作为燃料，导致广泛的代谢组学改变。 调节异常导致膜结构和功能发生多种有害改变。期间 目前的授权间隔，我们已经利用我们开发的使能质谱技术来识别 我们假设糖尿病心肌中过多的新信号分子对糖尿病心肌的 糖尿病心肌中的生物能量低效率和适应不良信号传导。我们认为这些新的信号 分子导致患有急性冠状动脉综合征的糖尿病患者的死亡率增加， 心肌梗死（MI）。此外，这些病理改变的后果，在信号通路中， 糖尿病心肌导致糖尿病患者MI后5年预后不良， 加速血流动力学损害的改变，并促进线粒体功能障碍， 糖尿病性心肌病脂质在细胞功能中起多效性作用，包括在细胞中产生能量的底物。 心肌糖尿病性心肌病的一个主要方面是脂质的不适应和功能失调的整合， 代谢与利用，从而导致有毒信号分子的产生。此前，通过 通过遗传学、药理学和化学生物学方法，我们鉴定了三种主要的磷脂酶， 心肌中的脂肪酶iPLA 2 β（PNPLA 9）、iPLA 2 γ（PNPLA 8）和iPLA 2 β（PNPLA 2; 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质 糖尿病心肌重塑。最近，我们证明了iPLA 2 γ及其下游信号传导， 代谢物启动了一个变革性的信号通路，这可能是许多多种有害物质的基础。 在糖尿病心肌中表现出变化。因此，在具体目标1中，我们将使用我们的质量使能套件， 光谱技术，以确定类型和数量的新的信号分子产生的这种 途径，并通过系统生物学方法确定其功能，以确定其在启动中的特定作用 和糖尿病性心肌病的传播。在具体目标2中，我们已经确定了一种新的机制， iPLA 200。因此，我们将确定激活的iPLA 2 β在介导适应性不良产生中的作用。 糖尿病心肌中的信号代谢物和糖尿病心肌中的信号代谢物使缺血。在具体目标3中，我们 将追踪糖尿病心肌中甘油三酯分子种类的显著变化， iPLA 2 β（PNPLA 2; ATGL）可能促进糖尿病心肌中的功能失调信号传导。总的来说，这些研究 是一种协同的多学科方法，以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小鼠， 药物发现的快速通道方法和将突出的药理学靶点转化为临床。

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.