OXIDANT-MEDIATED ENDOTHELIAL TOXICITY & LIPID SIGNALING

氧化剂介导的内皮毒性

• 批准号: 2223861
• 负责人: VISWANATHAN NATARAJAN
• 金额: $ 20.59万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-06-10 至 1998-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2223861
• 关键词: G protein; animal tissue; biological signal transduction; blood vessel disorder; calcium; cell free system; enzyme activity; high performance liquid chromatography; human tissue; lipid metabolism; membrane lipids; oxidative stress; phase contrast microscopy; phospholipase D; phospholipids; protein kinase C; pulmonary artery; scintillation spectrometry; thin layer chromatography; vascular endothelium; vascular endothelium permeability

Oxidant stress may participate in the evolution of vascular damage and loss of barrier function leading to the development of atherosclerosis, adult respiratory distress syndrome and vasculitis. Mechanisms of oxidant-induced endothelial barrier dysfunction are not well understood but likely involve modulation of lipid signalling pathways. Protein kinase C (PKC) has been implicated in oxidant-mediated disruption of normal barrier function, as activation of PKC alters in vitro endothelial cell permeability. Protein kinase C is activated by an endogenous activator, diacylglycerol (DAG) , a product of phospholipase C (PLC) catalyzed hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2). However, PLC-catalyzed PIP2 hydrolysis cannot account for all DAG accumulation suggesting other important DAG generating mechanisms must exist. One such mechanism is phospholipase D (PLD) catalyzed hydrolysis of membrane phospholipids generating phosphatidic acid (PA) which is subsequently dephosphorylated by PA phosphatase to yield DAG. Thus, PLD-mediated generation of PA and DAG produces sustained activation of PKC which is important for the development of increased endothelial permeability leading to vascular dysfunction. The hypothesis that oxidant-induced activation of phospholipase D causes sustained activation of protein kinase C resulting in increased vascular permeability will be tested in endothelial cells from bovine pulmonary artery and human umbilical cord vein. The specific aims are: 1) to determine if oxidants mediate activation of endothelial cell PLD; 2) to investigate the potential role of Ca 2+ in the regulation of oxidant-mediated PLD activation; 3) to determine the regulatory role of protein kinase C in oxidant-mediated PLD activation and 4) To determine which membrane phospholipids serve as substrates for oxidant-induced PLD. 5) To determine the effect of oxidants on PLD activation in cell-free system. The long-term objectives are to provide new and important knowledge about signalling mechanisms in endothelial cells, and further establish mechanisms of oxidant-induced vascular permeability. A better understanding of signal transduction pathways and second-messengers may lead to the design of therapeutic agents directed against pulmonary oxidative injury.

氧化应激可能参与血管损伤的演变和 障碍功能的丧失导致动脉粥样硬化的发展， 成人呼吸窘迫综合征和血管炎。 机制 氧化剂引起的内皮屏障功能障碍尚不清楚 但可能涉及脂质信号通路的调节。 蛋白质 激酶C（PKC）与氧化剂介导的破坏有关 正常的屏障功能，随着PKC的激活在体外内皮变化 细胞渗透性。 蛋白激酶C被内源性激活 激活剂二酰基甘油（DAG），磷脂酶C（PLC）的产物 磷脂酰肌醇4,5-双磷酸盐的催化水解（PIP2）。 但是，PLC催化的PIP2水解不能解释所有DAG 累积表明其他重要的DAG生成机制必须 存在。 一种这样的机制是磷脂酶D（PLD）催化的水解 产生磷脂酸（PA）的膜磷脂的磷脂 随后通过PA磷酸酶去磷酸化以产生DAG。 因此， PLD介导的PA和DAG的产生产生持续的激活 PKC对于开发增加内皮很重要 导致血管功能障碍的渗透性。 假设是 氧化剂诱导的磷脂酶D激活导致持续激活 蛋白激酶C的C导致血管通透性增加将是 在牛肺动脉和人的内皮细胞中测试 脐带静脉。 具体目的是：1）确定氧化剂是否是氧化剂 介导内皮细胞PLD的激活； 2）调查 Ca 2+在调节氧化剂介导的PLD中的潜在作用 激活; 3）确定蛋白激酶C在中的调节作用 氧化剂介导的PLD激活和4）确定哪种膜 磷脂作为氧化剂诱导的PLD的底物。 5）到 确定氧化剂对无细胞系统中PLD激活的影响。 长期目标是提供有关的新重要知识 内皮细胞中的信号传导机制，并进一步建立 氧化剂诱导的血管通透性的机制。 更好 了解信号转导途径和第二门的理解 导致针对肺的治疗剂的设计 氧化损伤。