RICKETTSIA RICKETTSII IN HUMAN ENDOTHELIAL CELLS

人内皮细胞中的立克次体

• 批准号: 3127208
• 负责人: DAVID J SILVERMAN
• 金额: $ 11.66万
• 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 1989-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3127208
• 关键词: Rickettsia; Rocky Mountain spotted fever; antioxidants; bacterial cytopathogenic effect; cytolysis; diene; electron microscopy; glutathione; histopathology; host organism interaction; human tissue; lipid peroxides; liposomes; membrane lipids; microorganism metabolism; platelet aggregation; radiotracer; scanning electron microscopy; steroids; superoxide dismutase; 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. The putative target cells of infection are the endothelial cell and occasionally smooth muscle cells of small blood vessels. The primary purpose of this investigation is to determine the specific mechanism of cell injury to human vascular endothelial cells cause by R. rickettsii, and to examine the potential biological ramifications of platelet adherence to infected endothelial cells. Understanding of the mechanism of cell injury by R. rickettsii and the consequences of platelet adherence to a normally non-thrombogenic surface should contribute considerably to a better undertanding of the pathogenesis of RMSF, and could provide for more specific therapeutic management of severe forms of the disease. This study will be carried out exclusively in human endothelial cells derived from the umbilical vein using combined biochemical and electron microscopic techniques. The hypothesis that endothelial cell injury caused by R. rickettsii is the direct result of intracellular rickettsial metabolism, will be tested. Specifically, that lipid peroxidation of intracellular membranes by toxic free radicals leads to dilatation and disorganization of the ER and eventually to lysis of the cell. Analysis of levels of malonaldehyde, the primary degradation product of peroxidation, and superoxide anion and superoxide dismutase will be carried out as well as the activity of two ER membrane markers, glucose-6-phosphatase and cytochrome P-450 which are destroyed as a result of peroxidation. Steroids and the antitoxidants glutathione and vitamin E will be examined for their protective capacity as free radical scavengers. The effects of superoxide dismutase incorporated into unilamellar liposomes and added to R. rickettsii-infected endothelial cells will be studied to determine whether cell injury caused by the organisms can be modified. Studies on platelet adherence using [3H] adenine and scanning electron microscopy, and the activation status of adherent platelets using [3H] serotonin will also be studied. Lastly, as a prelude to a future study, an attempt will be made to isolate and characterize plasmid DNA from R. rickettsii.

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。假定的目标 感染的细胞是内皮细胞，偶尔还有平滑肌。 小血管的细胞。这次调查的主要目的是 确定细胞损伤人血管的具体机制 里氏杆菌引起的内皮细胞，并检测其潜力 血小板与感染内皮细胞黏附的生物学效应 细胞。对立克次体和立克次体细胞损伤机制的认识 正常情况下不会导致血栓形成的血小板黏附的后果 地面应大大有助于更好地了解 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。 这项研究将专门在人类血管内皮细胞中进行 利用生化和电子相结合的方法从脐静脉提取 显微技术。内皮细胞损伤导致 立克次体是细胞内立克次体的直接结果 新陈代谢，将受到考验。具体地说，其脂质过氧化 有毒自由基引起的细胞内膜扩张和 内质网的解体，最终导致细胞的溶解。分析 过氧化的主要降解产物丙二醛的水平， 超氧阴离子和超氧化物歧化酶也将被进行 作为两种ER膜标志物的活性，葡萄糖-6-磷酸酶和 细胞色素P-450由于过氧化作用而被破坏。类固醇 抗氧化剂谷胱甘肽和维生素E将被检查它们的 作为自由基清除剂的保护能力。超氧物的作用 将歧化酶掺入单层脂质体中，加入到R。 将对感染立克次体的内皮细胞进行研究，以确定 由生物体造成的细胞损伤是可以修改的。关于血小板的研究 用[~3H]腺嘌呤和扫描电子显微镜进行黏附，以及 使用[~3H]5-羟色胺的黏附的血小板的激活状态也将是 学习。最后，作为未来研究的前奏，本文将进行一次尝试 目的分离立克次体质粒DNA，并对其进行鉴定。