RICKETTSIA-INDUCED TRANSCRIPTIONAL ACTIVATION

描述（改编自申请人摘要）： 本申请旨在了解内皮细胞 细胞-立克次体相互作用引起细胞反应， 立克次体病的发病机制。 血管细胞内感染 内皮细胞与R.立克次氏体导致基因改变 转录导致促凝血和促炎的表达 分子。 这些内皮细胞的反应可能是重要的， 与人类感染相关的病理变化，导致 落基山斑疹热（Rocky Mountain Spotted Fever，RMSF） 初步研究 表明R.立克次体感染导致 转录因子，核因子-kB（NF-kB），控制表达 许多诱导基因参与炎症刺激的早期反应。 今后的研究重点将放在R.立克次体诱导的NF-κ B activation. 该提案分为两个具体目标。 第一 具体目标将集中于表征NF-kB活化， 在用R.立克次氏体， 并将包括活化动力学的研究以及分子 活化复合物的表征。 第二个具体目标将 利用两种实验方法探索细胞内信号传导 R.立克次氏体诱导的NF-κ B活化。 探讨 生物体的重要特征在引发这种细胞 响应，开发了一个系统来研究分离的NF-kB的激活。 寄主细胞质 通过绕过进入过程，该系统将允许 对立克次氏体的广泛操作仍然允许直接 立克次体与宿主细胞信号机制的相互作用。 的抑制剂 关键的调节分子也将用于完整细胞， 感染的细胞内“靶标”导致激活。 的 研究人员推测R.立克次氏体诱导的NF-κ B活化是 通过生物体与宿主细胞组分的相互作用介导，但是， 该反应可能与已知的生理诱导剂稍有不同 关于动力学和同种型特异性。 自从一个主要事件在 RMSF的过程是广泛的微血管血栓形成，从 这些研究不仅在内皮细胞中提供了有价值的见解， 参与立克次体病，但在一般血栓性疾病。

DESCRIPTION (Adapted from the applicant's abstract): Studies described in this application are designed to understand mechanisms by which endothelial cell-rickettsia interactions elicit cellular responses critical to the pathogenesis of rickettsial disease. Intracellular infection of vascular endothelial cells with R. rickettsii results in changes in gene transcription leading to expression of procoagulant and proinflammatory molecules. These endothelial cell responses are likely important in the pathologic changes associated with human infection, which results in the disease known as Rocky Mountain Spotted Fever (RMSF). Preliminary studies indicate that R. rickettsii infection results in activation of the transcription factor, nuclear factor -kB (NF-kB), which controls expression of many inducible genes involved in early responses to inflammatory stimuli. The studies proposed will focus on mechanisms of R. rickettsii induced NF-kB activation. The proposal is divided into two specific aims. The first specific aim will concentrate on characterization of NF-kB activation which occurs during infection of cultured endothelial cells with R. rickettsii, and will include study of the kinetics of activation as well as molecular characterization of the activated complex. The second specific aim will utilize two experimental approaches to explore intracellular signaling pathways operative in R. rickettsii-induced NF-kB activation. To explore characteristics of the organism important in eliciting this cellular response, a system was developed to study activation of NF-kB in isolated host cell cytoplasm. By bypassing the entry process, this system will allow extensive manipulation of the rickettsia organisms yet still allow direct interaction of rickettsia with host cell signaling machinery. Inhibitors of key regulatory molecules will also be used in intact cells to identify intracellular "targets" of infection resulting in activation. The investigators hypothesize that R. rickettsii induced NF-kB activation is mediated via interaction of the organism with host cell components, but that the response likely differs somewhat from known physiologic inducers with regard to kinetics and isoform specificity. Since a primary event in the course of RMSF is extensive microvascular thrombosis, insights gained from these studies may provide valuable insights not only in endothelial cell involvement in rickettsial disease, but in thrombotic disease in general.