THE INTEGRATED ROLES OF IPLA2G IN OBESITY, INFLAMMATION AND HEPATIC DYSFUNCTION

IPLA2G 在肥胖、炎症和肝功能障碍中的综合作用

• 批准号: 9325506
• 负责人: RICHARD W GROSS
• 金额: $ 34.31万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-25 至 2019-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9325506
• 关键词: Ablation; Active Sites; Adipocytes; Affect; Animals; Attenuated; Bioenergetics; Biological Assay; Calcium; Cause of Death; Communication; Consumption; Coupling; Development; Diabetes Mellitus; Diagnostic; Diglycerides; Eicosanoids; Energy Metabolism; Enzymes; Euglycemic Clamping; Exhibits; Fatty Liver; Fatty acid glycerol esters; Functional disorder; Generations; Genetic; Genetic Models; Goals; Hepatic; Hepatocyte; High Fat Diet; IRS1 gene; Industrialization; Inflammation; Inflammatory; Insulin Resistance; Knock-out; Knockout Mice; Lead; Lipids; Liver; Liver diseases; LoxP-flanked allele; Mass Spectrum Analysis; Mediating; Mediator of activation protein; Metabolic; Metabolism; Mitochondria; Molecular; Monoglycerides; Morbidity - disease rate; Mus; Muscle Cells; Muscle Fibers; Obesity; Obesity associated disease; Organ; Organelles; Pathologic; Pathology; Patients; Pharmacological Treatment; Pharmacology; Phenotype; Phospholipase; Phosphorylation; Physiological; Process; Production; Protein Isoforms; Reagent; Research; Resistance; Respiration; Role; Signal Transduction; Skeletal Muscle; Societies; System; Technology; Tissues; Transgenic Organisms; Triglycerides; Validation; body system; cell type; experimental study; feeding; glucose tolerance; glucose uptake; glycogenolysis; hepatic gluconeogenesis; improved; in vivo; insight; insulin sensitivity; insulin signaling; interdisciplinary approach; lipid mediator; lipid metabolism; liver inflammation; loss of function; metabolomics; mitochondrial dysfunction; mitochondrial metabolism; mortality; novel; novel strategies; obesity treatment; peroxisome; public health relevance; screening; skeletal muscle metabolism; spatiotemporal; synergism; transacylation

DESCRIPTION (provided by applicant): The major causes of mortality and morbidity in industrialized societies result from the multiple downstream sequelae of high fat diet-induced obesity (HFDIO). Previously, we demonstrated the importance of calciumindependent phospholipase A2γ(iPLA2γ) as a central enzymic mediator integrating cellular signaling and organismal bioenergetics through the generation and characterization of a global iPLA2γ KO mouse. Remarkably, the iPLA2γ knockout mouse was completely resistant to HFDIO and the development of insulin resistance. However, due to the multiple organ systems affected in the whole animal iPLA2γ knockout, the mechanistic roles of iPLA2γ in each tissue contributing to the complete resistance of this mouse to HFDIO are unknown. The overarching goal of the proposed research is the mechanistic determination of the tissue- and organelle-specific roles of iPLA2γ in promoting inflammation, maladaptive cellular signaling and dysfunctional bioenergetics that result in insulin resistance and the pathologic end-organ sequelae of HFDIO. Accordingly, we generated mice containing a floxed construct of the iPLA2γ active site which has been crossed with tissue specific Cre mice resulting in the generation of hepatocyte-specific and skeletal muscle myocyte-specific iPLA2γ knockout mice. The proposed research will synergistically use these enabling genetic models in conjunction with the integrated lipidomics and metabolomics platforms we developed to identify the mechanisms through which iPLA2γ participates in the development of obesity, inflammation, and insulin resistance during HFDIO. The first specific aim will identify the roles of hepatocyte-specific iPLA2γ in mediating alterations in the generation of lipid 2nd messengers, lipid metabolism, hepatosteatosis and bioenergetics during HFDIO unencumbered by the effects of iPLA2γ loss of function in other cell types that are present in the germline knockout. In Specific Aim 2, we will examine the effects of skeletal muscle myocyte-specific ablation of iPLA2γ on skeletal muscle metabolism, insulin resistance and mitochondrial dysfunction that are present during high fat feeding in WT mice, but are rescued in the germline knockout mouse. Finally, in Specific Aim 3, we will determine the interactive mechanistic roles of the organelle-specific isoforms of iPLA2γ through the transgenic reintroduction of either the mitochondrial-specific or peroxisomal-specific isoforms of iPLA2γ into the hepatocyte-specific iPLA2γ knockout mouse. Moreover, the mechanisms through which lipid 2nd messengers generated by iPLA2γ in hepatocytes, skeletal muscle myocytes and adipocytes mediate inter-organ communication between these metabolically interwoven tissues will be identified through synergistic highly penetrating technologies we have developed/refined. Through this multidisciplinary approach employing novel genetic reagents, high mass accuracy mass spectrometry technologies and integrated chemophysiologic approaches, novel pharmacologic targets to attenuate the sequelae of HFDIO can be identified.

描述（由申请人提供）：工业化社会中死亡率和发病率的主要原因是高脂饮食诱导的肥胖症（HFDIO）的多种下游后遗症。先前，我们通过产生和表征整体iPLA 2 γ KO小鼠，证明了钙非依赖性磷脂酶A2γ（iPLA 2 γ）作为整合细胞信号传导和生物体生物能量学的中心酶介体的重要性。值得注意的是，iPLA 2 γ敲除小鼠对HFDIO完全耐受，并出现胰岛素抵抗。然而，由于在整个动物iPLA 2 γ敲除中受影响的多个器官系统，iPLA 2 γ在每个组织中促成该小鼠对HFDIO的完全抗性的机制作用是未知的。拟议研究的总体目标是从机制上确定iPLA 2 γ在促进炎症、适应不良的细胞信号传导和功能失调的生物能量学中的组织和细胞器特异性作用，这些作用导致胰岛素抵抗和HFDIO的病理性终末器官后遗症。因此，我们产生了含有iPLA 2 γ活性位点的floxed构建体的小鼠，其已与组织特异性Cre小鼠杂交，导致产生肝细胞特异性和骨骼肌肌细胞特异性iPLA 2 γ敲除小鼠。拟议的研究将协同使用这些使能遗传模型，结合我们开发的整合脂质组学和代谢组学平台，以确定iPLA 2 γ在HFDIO期间参与肥胖，炎症和胰岛素抵抗发展的机制。第一个具体目标将确定肝细胞特异性iPLA 2 γ在HFDIO期间介导脂质第二信使产生、脂质代谢、脂肪肝和生物能量学改变中的作用，而不受生殖系敲除中存在的其他细胞类型中iPLA 2 γ功能丧失的影响的影响。在特定目标2中，我们将检查骨骼肌肌细胞特异性消融iPLA 2 γ对WT小鼠高脂喂养期间存在的骨骼肌代谢、胰岛素抵抗和线粒体功能障碍的影响，但在种系基因敲除小鼠中得到挽救。最后，在具体目标3中，我们将通过将iPLA 2 γ的胰腺特异性或过氧化物酶同工酶特异性同工酶转基因重新引入肝细胞特异性iPLA 2 γ敲除小鼠，确定iPLA 2 γ的细胞器特异性同工酶的相互作用机制。此外，将通过我们开发/改进的协同高穿透性技术来鉴定肝细胞、骨骼肌肌细胞和脂肪细胞中iPLA 2 γ产生的脂质第二信使介导这些代谢交织组织之间器官间通讯的机制。通过采用新型基因试剂、高质量准确度质谱技术和综合化学生理学方法的这种多学科方法，可以鉴定减轻HFDIO后遗症的新型药理学靶点。