RICKETTSIA RICKETTSII IN HUMAN ENDOTHELIAL CELLS

人内皮细胞中的立克次体

• 批准号: 3127216
• 负责人: DAVID J SILVERMAN
• 金额: $ 20.22万
• 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/3127216
• 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; oxidative stress; 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.

落基山斑疹热（RMSF），由立克次氏体引起， 被认为是最严重的人类立克次体病。通常发送 通过蜱虫的叮咬，这些生物在吸血过程中被引入 直接在皮肤下侵入并破坏内皮细胞 小血管的细胞。我们的实验室已经建立了一个体外 研究立克次体-宿主相互作用的不同参数的模型 包括受此感染的内皮细胞的损伤机制， 有机体了解细胞损伤的具体机制 由R.立克次氏体应该大大提高现有的知识， 研究RMSF的发病机制，为临床治疗RMSF提供更有针对性的方法 管理严重的疾病形式。 这项研究将主要在培养的人 来源于脐静脉的内皮细胞。将细胞 以单层感染R.立克次体的高，中， 或低毒性。目前的证据表明，R。 自由基介导立克次体诱导的内皮细胞损伤 导致细胞膜脂质过氧化。这一假设将是 在以下方面进行：（a）鉴定特定脂质 使用高性能， （B）对R.立克次氏体 不同程度的毒力及其感染、复制和 通过显微镜和生物化学确定损伤内皮细胞 技术;（c）测定比较的细胞内水平 还原型谷胱甘肽和酶，过氧化氢酶和谷胱甘肽过氧化物酶， 抗氧化应激的固有细胞防御机制的量度; 和（d）谷胱甘肽前体，γ-谷氨酰半胱氨酸， 降低细胞内过氧化物水平并消除内皮细胞 损伤