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（通过应用提供）：工业化社会死亡率和发病率的主要原因是由于高脂饮食诱发的肥胖症（HFDIO）的多重下游后遗症所致。以前，我们通过全局IPLA2γKO小鼠的生成和表征来综合细胞信号传导和有机生物能力，证明了钙独立的磷脂酶A2γ（IPLA2γ）作为中心酶介体的重要性。值得注意的是，IPLA2γ基因敲除小鼠完全抵抗HFDIO和胰岛素抵抗的发展。但是，由于整个动物IPLA2γ敲除中的多种生物体系统，IPLA2γ在每个组织中的机械作用促成了该小鼠对HFDIO的完全抗性。提出的研究的总体目标是确定IPLA2γ组织和细胞器特异性作用在促进炎症，适应不良的细胞信号传导和功能障碍的生物能源方面，从而导致胰岛素抵抗以及HFDIO的病理端 - 器官频率。根据拟议的研究，我们将协同使用这些使遗传模型与综合脂肪组学和代谢组学平台结合使用，我们开发的，以确定IPLA2γ参与HFDIO期间肥胖，感染和胰岛素抵抗的机制。第一个具体目的将确定肝细胞特异性IPLA2γ在介导脂质第二个使者，脂质代谢，肝硬化和生物能力过程中的介导变化中的作用，而不是由IPLA2γ丢失在其他细胞类型中的影响，而这些细胞类型的效果均来自其他细胞类型的效果。在特定的目标2中，我们将研究IPLA2γ的骨骼肌心肌特异性消融对骨骼肌代谢，胰岛素抵抗和线粒体功能障碍的影响，在WT小鼠的高脂喂养过程中存在，但在胚芽敲除小鼠中受到响应。最后，在特定的目标3中，我们将通过对IPLA2γ的线粒体特异性或过氧特异性亚型的IPLA2γ的有机体特异性同工型的相互作用机械作用，这是IPATCYMAL特异性的特异性同工型中的肝细胞特异性特异性同工型。此外，IPLA2γ在肝细胞，骨骼肌心肌细胞和脂肪细胞中介导这些代谢性交织的组织之间的脂质第二个使者通过协同跨性能的技术鉴定我们已经开发了我们已经开发了/精炼的机制。通过采用新型遗传试剂的这种多学科方法，可以鉴定出高质量准确性质谱技术和集成的化学生理方法，可以确定可以识别出新型的药理学靶标，以减轻HFDIO的后遗症。