RICKETTSIA RICKETTSII IN HUMAN ENDOTHELIAL CELLS

人内皮细胞中的立克次体

• 批准号: 3127210
• 负责人: DAVID J SILVERMAN
• 金额: $ 16.94万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 1980
• 资助国家: 美国
• 起止时间: 1980-12-01 至 1993-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3127210
• 关键词: Rickettsia; Rocky Mountain spotted fever; antioxidants; bacterial cytopathogenic effect; cytolysis; diene; electron microscopy; glutathione; high performance liquid chromatography; histopathology; host organism interaction; human tissue; lipid peroxides; liposomes; membrane lipids; microorganism metabolism; radiotracer; scanning electron microscopy; steroids; tocopherols; vascular endothelium; vascular smooth muscle; virulence

Rocky Mountain spotted fever (RMSF), caused by Rickettsia rickettsii, is considered the most severe of the human rickettsioses. Usually transmitted by the bite of a tick, the organisms are introduced during a blood meal directly beneath the skin where they invade and destroy the endothelial cells of small blood vessels. Our laboratory has established an in vitro model to study different parameters of rickettsiae-host interaction including mechanisms of injury to endothelial cells infected by this organism. An understanding of the specific mechanism(s) of cell injury caused by R. rickettsii should significantly enhance existing knowledge of the pathogenesis of RMSF, and could provide for more specific therapeutic management of severe forms of the disease. The proposed study will be carried out primarily in cultured human endothelial cells derived from the umbilical vein. The cells will be infected as monolayers by strains of R. rickettsii of high, intermediate, or low virulence. Current evidence strongly suggests that R. rickettsii-induced endothelial cell injury is mediated by free radicals that cause peroxidation of cell membrane lipids. This hypothesis will be pursued in the context of : (a) identification of the specific lipid hydroperoxides formed in infected endothelial cells using high-performance liquid chromatography; (b) an analysis of strains of R. rickettsii of varying degrees of virulence and their capacity to infect, replicate, and injure endothelial cells as determined by microscopic and biochemical techniques; (c) determination of comparative intracellular levels of reduced glutathione and the enzymes, catalase and glutathione peroxidase as a measure of inherent cellular defense mechanisms against oxidative stress; and (d) the capacity of the glutathione precursor, gamma-glutamylcysteine, to reduce intracellular peroxide levels and abrogate endothelial cell injury.

由立克次体引起的落基山斑点热(RMSF)是 被认为是最严重的人类立克次体病。通常传输 被扁虱咬了一口，细菌就会在一顿血餐中传入 直接在皮肤下面，在那里它们入侵和破坏内皮细胞 小血管的细胞。我们实验室已经建立了一种体外培养方法 研究立克次体-宿主相互作用不同参数的模型 包括该病毒感染对内皮细胞的损伤机制 有机体。对细胞损伤具体机制的理解(S) 由立克次体引起的应该会显著增强现有的关于 RMSF的发病机制，并可提供更特异的治疗方法 严重形式的疾病的管理。 这项拟议的研究将主要在培养的人类身上进行。 来源于脐静脉的内皮细胞。牢房将会是 以单层形式感染高度、中等、 或低毒力。目前的证据有力地表明，R. 里氏杆菌致内皮细胞损伤是由自由基介导的 导致细胞膜脂质过氧化的物质。这一假设将是 在以下方面进行研究：(A)确定特定的脂类 高效免疫球蛋白在感染内皮细胞中形成的氢过氧化产物 高效液相色谱法；(B)里氏立克次杆菌菌株分析 不同程度的毒力及其感染、复制和 镜检和生化检测对内皮细胞的损伤作用 技术；(C)细胞内相对水平的测定 还原型谷胱甘肽及其酶、过氧化氢酶和谷胱甘肽过氧化物酶 一种针对氧化应激的固有细胞防御机制的测量； 和(D)谷胱甘肽前体--γ-谷氨酰半胱氨酸的能力， 降低细胞内过氧化氢水平，清除内皮细胞 受伤。