RICKETTSIA RICKETTSII IN HUMAN ENDOTHELIAL CELLS

描述（改编自申请人摘要）：长期目标 并且本申请的具体目的是了解 立克次氏体和其他成员的斑点热组 通过更好地研究引起细胞损伤的过程来研究立克次体。 研究人员对R.立克次氏体（洛基 山斑疹热）与内皮细胞，在人类的靶细胞 感染，以及由这种专性感染引起的细胞损伤的机制 胞内细菌主要研究者已确定 实验室认为细胞损伤似乎是由活性氧引发的 在内化和细胞内立克次体生长过程中产生。与 为了消除内皮细胞损伤，他们将 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素， 活性氧物质，并大大延长 感染的细胞培养物。迄今为止的研究已经在人类和 脐静脉内皮细胞和永久性人内皮细胞系， EA.hy926.研究人员将继续在这些领域进行实验。 细胞，以表征内皮细胞细胞骨架的变化 继R。立克次体感染，并评估这些之间的联系， 内皮通透性的变化和增加。他们将决定是否 R.立克次氏体诱导的氧化损伤是导致 肌动蛋白池，以及这些变化是否可以被预防（控制）， 使用抗氧化剂。他们认为，检验我们的能力也很重要。 在相关动物模型中对氧化剂介导的损伤的体外观察， 确定是否发生氧化损伤，以及抗氧化剂是否有效， 改变疾病的进程。这些研究最合适的模型是 已被广泛研究的康氏立克次体-C3 H/HeN小鼠模型 由步行者和他的同事完成。R. conorii与R.立克次氏体， 引起地中海斑疹热，一种临床上类似于RMSF的综合征， 正如他们所展示的，结果是同样戏剧性的形态学， 细胞损伤表现为R.人内皮细胞中的立克次氏体。 这些初步的体外研究和小鼠模型研究表明， 这种立克次氏体还能够引起氧化应激。他们打算测试 假设氧化损伤有助于内的病理变化 那个禽兽他们将确定氧化损伤是否与 在特定器官和组织内局部存在立克次体， 抗氧化剂α-硫辛酸可以改善氧化损伤，因为它们 在试管中显示。

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.