Pseudomonas aeruginosa-induced host cell pathogenesis

描述（由申请人提供）：铜绿假单胞菌（PA）是一种机会性革兰氏阴性病原体，导致大量医院感染。Joanne Engel博士和她的团队已经证明PA103通过III型分泌系统（TTSS）依赖机制诱导上皮细胞和巨噬细胞的凋亡样细胞死亡。与其他人的结果一致，他们发现这是一个Fas配体和Fas受体依赖的过程。我们认为，pa诱导的细胞凋亡发生在以下两种情况下：(A) TTSS将细菌效应物（PAF，假单胞菌凋亡因子）直接易位到宿主细胞中，导致fas依赖性细胞凋亡的激活，或(B) III型易位装置本身的一种或多种成分直接诱导fas依赖性细胞凋亡。我们将确定PAl03在真核细胞中诱导tts依赖性凋亡样细胞死亡的机制。我们将首先使用遗传和蛋白质组学方法来鉴定推定的诱导凋亡的III型分泌效应分子。我们也可以验证另一种假设，即TTSS本身负责PA诱导细胞凋亡。我们将在缺乏编码TTSS质粒的耶尔森菌菌株中表达PA TTSS，并测试其诱导凋亡活性的恢复。

DESCRIPTION (provided by applicant): Pseudomonas aeruginosa (PA) is an opportunistic gram-negative pathogen responsible for a large number of nosocomial infections. Dr. Joanne Engel and her group have shown that PA103 induces apoptotic-like cell death in epithelial cells and macrophages by a Type III Secretion System (TTSS)-dependent mechanism. Consistent with the results of others, They have found this to be a Fas ligand- and Fas receptor-dependent process. We propose that PA-induced apoptosis occurs either by (A) direct translocation of a bacterial effector into the host cell (PAF, for Pseudomonas Apoptosis Factor) by the TTSS, resulting in activation of Fas-dependent apoptosis or by (B) direct induction of Fas-dependent apoptosis by one or more components of the type III translocation apparatus itself. We will identify the mechanism by which PAl03 induces TTS-dependent apoptotic-like cell death in eukaryotic cells. We will initially use genetic and proteomic approaches to identify a putative apoptosis-inducing type III secreted effector molecule. We may also test the alternative hypothesis that the TTSS itself is responsible for the induction of apoptosis by PA. We will express the PA TTSS in a Yersinia strain that lacks the plasmid encoded TTSS and test for restoration of apoptosis-inducing activity.