Molecular Pathogenesis of Rickettsioses and Development of Novel Anti- Rickettsial Treatment by Combinatorial Peptide-Based Libraries

摘要

The purpose of this study is to utilize adaptein libraries coded within pantropic retroviral vectors that confer protection against rickettsiae and to study the molecular pathogenesis of rickettsioses. The following specific aims were proposed: 1) To establish heterogeneous cell populations, with each cell expressing a unique member of a complex combinatorial peptide- based (e.g., adaptein) library and challenge with R. prowazekii, R. rickettsii, and O. tsutsugamushi; 2) To determine the role of NF-kB, cytokines, ROS and NO in intracellular killing of rickettsia-infected monolayers containing adapteins and 3) To characterize signal transduction pathways modulating the cytoskeletal events responsible for the increased vascular permeability. Work on specific aim 1 was partially successful. Resistant colonies of 20-25 cells were obtained after rickettsial challenges. However, expansion of such colonies was not possible. Great progress was made on specifics aims 2 and 3. The role of rickettsiae, cytokines (IFN-gamma, TNF-alpha, and IL-1beta), ROS and NO in endothelial permeability was very well characterized in vitro. Changes in occludin, p120 and beta-catenin have also been documented by confocal microscopy and are related to increased endothelial permeability. mRNA microarray experiments revealed differences between infected and non-infected endothelial monolayers and between R. conorii and R. rickettsii-infected endothelial monolayers.