Analysis of an orchestrated cell death mediated by Vibrio parahaemolytics T3SS1

描述(由申请人提供)：本申请的最终目标是确定革兰氏阴性细菌副溶血性弧菌的III型分泌系统1(T3SS1)针对的宿主信号通路；副溶血性弧菌是与食用受污染的海鲜相关的胃肠炎爆发的主要病原体。副溶血性弧菌在环境中的流行和感染的发生率与全球变暖导致的水温上升有关。T3SS是一种针状结构，它有效地将毒力因子从细菌转移到宿主细胞的胞浆中。毒力因子(也称为细菌效应物)的进化方式与许多病毒致癌基因相似；真核细胞的活性被病原体篡夺和修改，以获得自身的优势。副溶血性弧菌的基因组测序显示存在两个致病岛，分别编码T3SS和可能的效应物。第一个致病岛含有T3SS1，与细胞毒性有关，而第二个致病岛含有T3SS2，与肠道毒性相关。第一个致病岛上的效应器已被鉴定为开放阅读框架，与任何已知蛋白质没有明显的同源性。最近，我们已经证明了副溶血性弧菌利用T3SS1通过诱导自噬、细胞圆化和细胞裂解来协调多方面的宿主细胞感染。我们已经证明了T3SS1效应器之一，VopS，利用一种新的翻译后修饰称为AMP化来干扰宿主信号。在此，我们提出了通过确定三个已知效应分子的活性和宿主靶标，识别T3SS1分泌的其他效应分子，以及在感染过程中被副溶血弧菌干扰的宿主信号通路来研究T3SS1诱导的多方面死亡的具体目标。这些研究为了解这种有害的胃肠道细菌病原体副溶血性弧菌所使用的分子机制提供了分子基础。

DESCRIPTION (provided by applicant): The ultimate goal of this application is to identify the host signaling pathways targeted by the type III secretion system 1 (T3SS1) of the gram-negative bacterium Vibrio parahaemolyticus; a major agent responsible for gastroenteritis outbreaks associated with the consumption of contaminated seafood. The prevalence of V. parahaemolyticus in the environment and incidence of infection have been linked to rising water temperatures caused by global warming. A T3SS is a needle-like structure that efficiently translocates virulence factors from bacteria into the cytosol of a host cell. The virulence factors (also called bacterial effectors) have evolved in a manner similar to many of the viral oncogenes; a eukaryotic activity is usurped and modified by the pathogen for its own advantage. Genomic sequencing of V. parahaemolyticus revealed the existence of two pathogenicity islands that encode both a T3SS and putative effectors. The first pathogenicity island contains T3SS1 and is associated with a cytotoxicity, while the second pathogenicity island contains T3SS2 and is associated with an enterotoxicity. The effectors on the first pathogenicity island have been identified as open reading frames with no obvious homology to any known protein. Recently, we have demonstrated that the V. parahaemolyticus uses T3SS1 to orchestrate a multifaceted host cell infection by induction of autophagy, cell rounding and then cell lysis. We have shown one of the T3SS1 effectors, VopS, utilizes a novel posttranslational modification called AMPylation to disrupt host signaling. Herein, we propose Specific Aims to study the multifaceted death induced by T3SS1 by identifying the activity and host targets of three known effectors, identify other effectors secreted by T3SS1 and characterize the host signaling pathways that are disrupted by V. parahaemolyticus during infection. These studies provide molecular insight into the molecular mechanisms used by this harmful gastrointestinal bacterial pathogen V. parahaemolyticus.