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REGULATION OF MYOCARDIAL PHOSPHOLIPASES AND LIPASES IN DIABETIC MYOCARDIUM

糖尿病心肌中心肌磷脂酶和脂肪酶的调节

基本信息

批准号：
8483030
负责人：
RICHARD W GROSS
金额：
$ 71.91万
依托单位：
WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-06-01 至 2017-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8483030
关键词：
Ablation Active Sites Acute Acyl Coenzyme A Acyltransferase Arachidonic Acids Attenuated Bioenergetics Biological Biological Assay Calcium Calcium ion Cardiac Cardiac Myocytes Cause of Death Cell membrane Cessation of life Charge Chemicals Chronic Coenzyme A-Transferases Complex Coupling Diabetes Mellitus Disease Eicosanoids Employee Strikes Endocannabinoids Energy Intake Enzymes Fatty Acids Fatty acid glycerol esters Functional disorder Generations Genetic Heart Heart Diseases Heart failure Homeostasis Hydrolysis Infarction Injury Ischemia Knock-out Knockout Mice Lead Lipase Lipids Lysophosphatidylcholines Lysophospholipase Lysophospholipids Mass Spectrum Analysis Mediating Mediator of activation protein Membrane Membrane Structure and Function Mitochondria Molecular Monoglycerides Mus Mutate Myocardial Myocardial Contraction Myocardial Ischemia Myocardium Necrosis Pathologic Pathway interactions Phospholipase Phosphorylation Phosphorylation Site Physiological Physiological Processes Production Protein Isoforms Proteins Regulation Reliance Reperfusion Therapy Role Serine Signal Transduction Signaling Molecule Site-Directed Mutagenesis Societies Stable Isotope Labeling Structure Sudden Death Testing Transacylase Transgenic Organisms Triglycerides Ventricular Arrhythmia calmodulin-dependent protein kinase II diabetic diabetic cardiomyopathy diabetic patient heart cell hemodynamics insulin signaling interdisciplinary approach loss of function lysophosphatidic acid metabolomics mitochondrial dysfunction mitochondrial permeability transition pore novel public health relevance transacylation

项目摘要

DESCRIPTION (provided by applicant): 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. However, 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. Consequences of these membrane-mediated abnormalities in diabetic myocardium include hemodynamic compromise, defective excitation-contraction coupling and mitochondrial dysfunction that collectively conspire to promote the progression of heart failure in diabetic patients. Moreover, the profound alterations in substrate utilization in diabetic myocardium result in the accumulation of multiple dysregulated metabolites that lead to maladaptive alterations in interwoven cardiac myocyte signaling networks. Previously, through genetic, pharmacologic and chemical biological approaches, we have identified three major phospholipases and lipases in myocardium iPLA2? (PNPLA9), iPLA2? (PNPLA8), and iPLA2? (PNPLA2; ATGL) that likely serve as principal mediators of myocardial hemodynamic dysfunction, electrophysiologic alterations and maladaptive remodeling in diabetic myocardium. Recently, we demonstrated that iPLA2g and its downstream signaling metabolites are key regulators of the mitochondrial permeability transition pore which is responsible for necrosis, necroptosis, and electrical instability in diabetic myocardium subjected to ischemia. Accordingly, in Specific Aim 1, we will use the novel cardiac myocyte specific iPLA2g conditional knock out mouse we generated to determine if iPLA2g loss of function attenuates acute ischemic injury, electrophysiologic instability and the maladaptive generation of lipid 2nd messengers in diabetic myocardium. Furthermore, we demonstrated that exposure of mitochondria to calcium ion results in the activation of iPLA2g leading to the release of arachidonic acid, 2-arachidonoyl lysophosphatidylcholine, and the subsequent production of multiple downstream biologically active lipid 2nd messengers. Accordingly, iPLA2g-dependent alterations in lipid 2nd messenger production will be examined employing integrative mass spectrometric platforms we developed in conjunction with the cardiac myocyte specific iPLA2g loss of function mouse. In Specific Aim 2, we will determine the molecular mechanisms through which acyl-CoA facilitates CaMKII phosphorylation and activation of iPLA2b. The activating phosphosite(s) will be identified, mutated and their mechanistic importance in CaMKII-mediated activation of iPLA2b in diabetic myocardium and diabetic myocardium rendered ischemic will be explored. In Specific Aim 3, the role(s) of iPLA2z (ATGL;PNPLA2) in catalyzing the bidirectional flux of lipids through triglyceride hydrolysis, transacylation and acyltransferase activities will e determined. The participation of iPLA2z in generating lipid 2nd messengers in diabetic myocardium will be examined using cardiac myocyte specific iPLA2z null mice and the effects of iPLA2z genetic ablation on myocardial function in the diabetic state will be explored. Collectively, these studies are a synergistic multidisciplinary approach to identify the chemical mechanisms mediating diabetic cardiomyopathy.

描述（由申请人提供）：糖尿病性心肌病是一种复杂的疾病，由于缺乏胰岛素信号，导致糖尿病心肌长期过量使用脂肪酸来促进收缩功能。然而，在糖尿病心肌中几乎完全使用脂肪酸作为燃料导致广泛的代谢组失调，从而导致膜结构和功能的多种有害改变。这些膜介导的糖尿病心肌异常的后果包括血流动力学损害、兴奋-收缩耦合缺陷和线粒体功能障碍，它们共同促进糖尿病患者心力衰竭的进展。此外，糖尿病心肌底物利用的深刻改变导致了积累