RICKETTSIA RICKETTSII IN HUMAN ENDOTHELIAL CELLS

描述（改编自申请人的摘要）：落基山 斑疹热是由立克次体引起的，是一种重要的 由于美国的感染情况极其严重 未经治疗的病例，难以建立早期临床或 实验室诊断，缺乏有效的预防手段。 通过蜱虫叮咬传播，生物体通过血液传播 整个身体，进入并损伤内皮细胞 微循环。 立克次体内皮细胞相互作用的体外模型 在当前的资助期间，Silverman 博士的实验室使用了领先的 建立重要的新研究循环，以实现高产研究 传染病发病机制的概念。 拟议的研究将 检查培养的感染毒力的人内皮细胞 希拉·史密斯菌株和无毒力的爱荷华立克次氏立克次体菌株 普罗瓦泽基立克次体的强毒力 Breinl 菌株和无毒力的马德里 E 菌株。 西尔弗曼博士实验室的当前证据强烈表明 立克次体诱导的内皮细胞损伤是由反应介导的 氧物种。 检测到大量超氧自由基 立克次体内化过程中培养上清液中的 内皮细胞。 调查员假设伤害已经开始 由于生物体的吞噬作用中止，导致 氧化爆发。 氧化爆发在细胞中释放超氧化物 细胞外超氧化物转化为有毒 H2O2 的表面 内皮糖萼中的歧化酶。 H202 容易通过 质膜，能够直接引起过氧化 膜脂，或者它可能与额外的超氧化物反应产生 羟基自由基的毒性更大。 过氧化氢酶和丙酮酸是已知的 H2O2 清除剂并保护内皮细胞免受过氧化氢的影响 由超氧化物生成。 立克次体引起的假设 吞噬作用失败导致内皮细胞损伤 用这些清除剂进行预处理，测量细胞内谷胱甘肽 并将它们与爱荷华州、布赖因尔和 马德里E菌株。

DESCRIPTION (Adapted from the Applicant's Abstract): Rocky Mountain spotted fever, caused by Rickettsia rickettsii, is an important infection in the United States owing to the extreme severity of untreated cases, the difficulty in establishing an early clinical or laboratory diagnosis, and the lack of an effective means of prevention. Transmitted by tick bite, the organisms are spread by the bloodstream throughout the body, entering and injuring endothelial cells of the microcirculation. The in vitro model of Rickettsia rickettsii endothelial cell interaction utilized in Dr. Silverman's laboratory has led during the current funding cycle to highly productive research with establishment of important new concepts of infectious disease pathogenesis. The proposed study will examine cultured human endothelial cells infected with the virulent Sheila Smith strain and the avirulent Iowa strain of R. rickettsii and the virulent Breinl and avirulent Madrid E strains of R. prowazekii. Current evidence from Dr. Silverman's laboratory strongly suggests that R. rickettsii induced endothelial cell injury is mediated by reactive oxygen species. Superoxide radical has been detected in large amounts in culture supernatants during internalization of rickettsiae into endothelial cells. The investigator postulates that injury is initiated as a result of aborted phagocytosis of the organism that results in an oxidative burst. The oxidative burst releases superoxide at the cell surface which is converted to toxic H202 by extracellular superoxide dismutase in the endothelial glycocalyx. H202 readily passes through the plasma membrane and is capable of directly causing peroxidation of membrane lipids, or it may react with additional superoxide to produce the even more toxic hydroxyl radical. Catalase and pyruvate are known scavengers of H202 and protect endothelial cells from hydrogen peroxide generated from superoxide. The hypothesis that R. rickettsii causes abortive phagocytosis leading to endothelial cell injury following pretreatment with these scavengers, measuring intracellular glutathione and comparing them to comparable experiments with the Iowa, Breinl and Madrid E strains.