Regulation of cPLA2 in macrophages during phagacytosis

巨噬细胞吞噬过程中 cPLA2 的调节

• 批准号: 7142867
• 负责人: CHRISTINA Carroll LESLIE
• 金额: $ 34.29万
• 依托单位: NATIONAL JEWISH HEALTH
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7142867
• 关键词: Candida albicans; Listeria; arachidonate; biological signal transduction; calcium; eicosanoids; enzyme activity; gene targeting; genetically modified animals; immunofluorescence technique; laboratory mouse; lipoxygenase; lung disorder; macrophage; microorganism immunology; phagocytosis; phospholipase A2; phosphorylation; protein degradation; proteolysis; toll like receptor; zymosan

The focus of Project 1 is to study the regulation of the ubiquitous Group IVA cytosolic phospholipase A (cPLA2), which initiates the production of numerous lipid second messengers such as lysophospholipids, platelet activating factor and eicosanoids. Targeted deletion of cPLA2 has shown that it plays a fundamental role in homeostasis (female reproduction, organ growth, kidney function) and inflammatory diseases (arthritis, acute lung injury, pulmonary fibrosis, bronchial reactivity), emphasizing the importance of lipid mediators in regulating cell processes. Production of eicosanoids also plays a role in innate immunity and is an early response of macrophages to microbial infection, mediating vascular permeability and emigration of leukocytes. cPLA2 is potently activated in macrophages during non-opsonic phagocytosis of zymosan and the pathogens, Candida albicans and Listeria monocy to genes. The objectives of this proposal are to elucidate the mechanisms of cPLA2 activation and inactivation during phagocytosis of these microorganisms in resident mouse peritoneal macrophages. It is hypothesized that cPLA2 (1) initiates eicosanoid production in response to microbial components that engage specific pattern recognition receptors, and (2) plays a role in determining the susceptibility to microbial infection. It is also hypothesized that during the course of phagocytosis, cPLA2 becomes inactivated, which limits eicosanoid production and the extent of inflammation. The specific aims are: (1) to investigate the role of dectin-1 and Toll-like receptors in mediating cPLA2 activation during phagocytosis of Candida albicans and Listeria monocytogenes; (2) to study the translocation of cPLA2 and 5-lipoxygenase, and the role of calcium signals; (3) to study the role of kinase activation and phosphorylation of cPLA2; (4) to study cPLA2 inactivation by oxidants and proteolytic degradation by caspases; and (5) to determine the role of cPLA2 in susceptibility to infection by these microorganisms. This project will provide detailed information about mechanisms regulating cPLA2 and production of eicosanoids, and their role in innate immunity to microbial infection.

项目1的重点是研究普遍存在的IVA族胞质磷脂酶A（cPLA 2）的调节，该酶启动许多脂质第二信使的产生，如溶血磷脂，血小板活化因子和类花生酸。cPLA 2的靶向缺失已经表明，它在稳态（女性生殖、器官生长、肾功能）和炎性疾病（关节炎、急性肺损伤、肺纤维化、支气管反应性）中起着重要作用，强调了脂质介质在调节细胞过程中的重要性。类二十烷酸的产生也在先天免疫中起作用，并且是巨噬细胞对微生物感染的早期反应，介导血管通透性和白细胞的迁移。cPLA 2在酵母聚糖和病原体白色念珠菌（Candida albicans）和单核李斯特菌（Listeria monocy）的非调理素吞噬作用期间在巨噬细胞中被有效地激活。本提案的目的是阐明这些微生物在小鼠腹腔巨噬细胞中的吞噬过程中cPLA 2激活和失活的机制。假设cPLA 2（1）响应于与特定模式识别受体结合的微生物组分而启动类花生酸的产生，并且（2）在确定对微生物感染的易感性中起作用。还假设在吞噬过程中，cPLA 2变得失活，这限制了类花生酸的产生和炎症的程度。具体目标是：（1）研究dectin-1和Toll样受体在白念珠菌和单核细胞增生李斯特菌吞噬过程中介导cPLA 2活化的作用，（2）研究cPLA 2和5-脂氧合酶的转位以及钙信号的作用，（3）研究cPLA 2激酶活化和磷酸化的作用，（4）研究cPLA 2的磷酸化和磷酸化的作用。（4）研究氧化剂对cPLA 2的灭活作用和半胱天冬酶对cPLA 2的蛋白水解降解作用;（5）确定cPLA 2在这些微生物感染易感性中的作用。该项目将提供有关调节cPLA 2和类花生酸产生的机制及其在微生物感染先天免疫中的作用的详细信息。