RICKETTSIA RICKETTSII IN HUMAN ENDOTHELIAL CELLS

描述(改编自申请人的摘要)：长期目标 而这一应用的具体目的是了解糖尿病的发病机制 立克次体和斑点热组的其他成员 通过更好地研究导致细胞损伤的过程，立克次体。 调查人员对Rrickettsii(Rocky)的相互作用感兴趣 高山斑点热)与人的靶细胞内皮细胞 感染，以及由此产生的细胞损伤机制(S) 胞内细菌。已由首席调查员确定 实验室认为细胞损伤似乎是由活性氧引起的 在内化和细胞内立克次体生长过程中产生。带着一个 对消除内皮细胞损伤的兴趣，他们已经将 抗氧化剂进入受感染的细胞培养系统。一种抗氧化剂(α-硫辛酸 酸，能够有效地逆转细胞损伤的主要预测因子 以产生活性氧，并大幅延长 被感染的细胞培养物。到目前为止，这两项研究都在人类 脐静脉内皮细胞和永久性人内皮细胞系， EA.hy926.调查人员将继续在这些地方进行实验 用于表征内皮细胞细胞骨架变化的细胞 在立克次体感染后，并评估这些之间的联系 血管内皮细胞通透性改变和增加。他们将决定是否 立克次体诱导的氧化损伤是导致细胞内 肌动蛋白池，以及这些变化是否可以通过 抗氧化剂的使用。他们认为，测试我们的能力也很重要 氧化损伤相关动物模型的体外观察 确定是否发生氧化损伤，以及抗氧化剂是否有效 改变病程。最适合这些研究的模型是 已被广泛研究的康氏立克次体-C3H/母鼠模型 沃克和他的同事写的。康氏立克次体与立克次体亲缘关系密切， 引起地中海斑点热，一种临床上类似于RMSF的综合征，以及 正如他们所证明的，结果是相同的戏剧性形态 人内皮细胞中立克次体的细胞损伤表现。 这些初步的体外研究和小鼠模型的研究表明， 这种立克次体也能引起氧化应激。他们提议测试 认为氧化剂损伤导致体内病理变化的假说 这只动物。他们将确定氧化损伤是否与 在特定器官和组织中局部存在立克次体，以及 抗氧化剂α-硫辛酸可以改善氧化损伤，因为它们 已经在体外显示出。

DESCRIPTION (Adapted from the Applicant's Abstract): The long-term objectives and specific aims of this application are to understand the pathogenesis of Rickettsia rickettsii, and other members of the spotted fever group of rickettsiae by better studying the processes involved in causing cell injury. The investigators are interested in the interaction of R. rickettsii (Rocky Mountain spotted fever) with the endothelial cell, the target cell in human infection, and the mechanism(s) of cell injury caused by this obligate intracellular bacterium. It has been determined by the Principal Investigator's laboratory that cell injury appears to be initiated by reactive oxygen species produced during internalization and intracellular rickettsial growth. With an interest in abrogating endothelial cell injury, they have incorporated antioxidants into infected cell culture systems. One antioxidant, (alpha-lipoic acid, was able to effectively reverse the leading predictors of cell injury due to reactive oxygen species and to substantially prolong the viability of infected cell cultures. Studies to date have been carried out both in human umbilical vein endothelial cells and the permanent human endothelial cell line, EA.hy926. The investigators will continue to carry out experiments in these cells to characterize changes in the cytoskeleton of endothelial cells following R. rickettsii infection and to evaluate the link between these changes and increases in endothelial permeability. They will determine whether R. rickettsii-induced oxidative injury is responsible for the alterations in the actin pools and whether these changes can be prevented (controlled) by the use of antioxidants. They believe that it is also important to test our in vitro observations on oxidant-mediated injury in a relevant animal model to determine whether oxidant injury occurs and if antioxidants are effective in altering the course of disease. The most suitable model for these studies is the Rickettsia conorii-C3H/HeN mouse model which has been extensively studied by Walker and his colleagues. R. conorii is closely related to R. rickettsii, causes Mediterranean spotted fever, a syndrome clinically similar to RMSF, and as they have demonstrated, results in the same dramatic morphological manifestations of cell injury as R. rickettsii in human endothelial cells. These preliminary in vitro studies and those in the mouse model, indicate that this rickettsia is also able to cause oxidative stress. They propose to test the hypothesis that oxidant injury contributes to the pathologic changes within the animal. They will determine whether oxidative injury correlates with the local presence of rickettsiae within particular organs and tissues and whether the antioxidant, alpha-lipoic acid, can ameliorate oxidative injury as they have shown in vitro.