权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

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：
9065644
负责人：
RICHARD W GROSS
金额：
$ 75.54万
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/9065644
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 Health Heart Heart Diseases Heart failure Homeostasis Hydrolysis Infarction Injury Ischemia Knock-out Knockout Mice Lead Lipase Lipids Lysophosphatidylcholines Lysophospholipase 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 PLA2G6 gene Pathologic Pathway interactions Phospholipase Phosphorylation Phosphorylation Site Physiological Physiological Processes Production Protein Isoforms Proteins Regulation 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 novel therapeutics 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 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 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 iPLA2γ conditional knock out mouse we generated to determine if iPLA2γ 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 iPLA2γ leading to the release of arachidonic acid, 2-arachidonoyl lysophosphatidylcholine, and the subsequent production of multiple downstream biologically active lipid 2nd messengers. Accordingly, iPLA2γ-dependent alterations in lipid 2nd messenger production will be examined employing integrative mass spectrometric platforms we developed in conjunction with the cardiac myocyte specific iPLA2γ loss of function mouse. In Specific Aim 2, we will determine the molecular mechanisms through which acyl-CoA facilitates CaMKII phosphorylation and activation of iPLA2ß. The activating phosphosite(s) will be identified, mutated and their mechanistic importance in CaMKII-mediated activation of iPLA2ß in diabetic myocardium and diabetic myocardium rendered ischemic will be explored. In Specific Aim 3, the role(s) of iPLA2ζ (ATGL;PNPLA2) in catalyzing the bidirectional flux of lipids through triglyceride hydrolysis, transacylation and acyltransferase activities will e determined. The participation of iPLA2ζ in generating lipid 2nd messengers in diabetic myocardium will be examined using cardiac myocyte specific iPLA2ζ null mice and the effects of iPLA2ζ 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传导，慢性和过度使用脂肪酸来刺激糖尿病心肌的收缩功能。然而，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学失调，从而导致膜结构和功能的多种有害改变。糖尿病心肌中这些膜介导的异常的后果包括血液动力学损害、有缺陷的兴奋-收缩偶联和线粒体功能障碍，这些共同共同促进糖尿病患者心力衰竭的进展。此外，糖尿病心肌中底物利用的深刻改变导致了导致交织的心肌细胞信号网络适应不良改变的多种失调代谢物。先前，通过遗传学、药理学和化学生物学方法，我们已经鉴定了心肌中的三种主要磷脂酶和脂肪酶iPLA 2 β（PNPLA 9）、iPLA 2 γ（PNPLA 8）和iPLA 2 β（PNPLA 2; ATGL），它们可能是糖尿病心肌中心肌血流动力学功能障碍、电生理学改变和适应不良重构的主要介质。最近，我们证明了iPLA 2 γ及其下游信号代谢产物是线粒体通透性转换孔的关键调节剂，线粒体通透性转换孔负责缺血的糖尿病心肌的坏死、坏死性凋亡和电不稳定。因此，在特定目标1中，我们将使用我们产生的新型心肌细胞特异性iPLA 2 γ条件性敲除小鼠来确定iPLA 2 γ功能丧失是否减弱糖尿病心肌中的急性缺血性损伤、电生理不稳定性和脂质第二信使的适应不良产生。此外，我们证明了线粒体暴露于钙离子导致iPLA 2 γ的活化，从而导致花生四烯酸、2-花生四烯酸溶血磷脂酰胆碱的释放，以及随后多种下游生物活性脂质第二信使的产生。因此，脂质第二信使产生中的iPLA 2 γ依赖性改变将使用我们与心肌细胞特异性iPLA 2 γ功能丧失小鼠联合开发的整合质谱平台来检查。在具体目标2中，我们将确定酰基辅酶A促进CaMKII磷酸化和iPLA 2A激活的分子机制。将鉴定、突变活化磷酸化位点，并探索它们在糖尿病心肌和缺血性糖尿病心肌中CaMK II介导的iPLA 2 β活化中的机制重要性。在具体目标3中，将确定iPLA 2 β（ATGL; PNPLA 2）在通过甘油三酯水解、转酰化和酰基转移酶活性催化脂质双向流动中的作用。将使用心肌细胞特异性iPLA 2 β敲除小鼠来检查iPLA 2 β在糖尿病心肌中产生脂质第二信使的参与，并将探索iPLA 2 β基因消融对糖尿病状态下心肌功能的影响。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。