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菌副溶血性弧菌III型分泌系统1（T3 SS 1）靶向的宿主信号通路;副溶血性弧菌是与食用受污染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发生率与全球变暖引起的水温上升有关。T3 SS是一种针状结构，其有效地将细菌的毒力因子易位到宿主细胞的胞质溶胶中。毒力因子（也称为细菌效应子）的进化方式与许多病毒致癌基因相似;真核生物的活性被病原体篡夺和修改以获得自身优势。副溶血性弧菌的基因组测序显示存在两个致病岛，编码T3 SS和推定的效应子。第一个致病岛含有T3 SS 1并与细胞毒性相关，而第二个致病岛含有T3 SS 2并与肠毒性相关。第一个致病岛上的效应子已被鉴定为开放阅读框，与任何已知蛋白没有明显的同源性。最近，我们已经证明，副溶血性弧菌使用T3 SS 1通过诱导自噬、细胞变圆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T3 SS 1效应子之一VopS利用一种称为AMP化的新型翻译后修饰来破坏宿主信号传导。在此，我们提出了具体的目的，通过确定三个已知的效应子的活性和宿主靶点，确定T3 SS 1分泌的其他效应子，并表征在感染期间被副溶血性弧菌破坏的宿主信号通路，来研究T3 SS 1诱导的多方面死亡。这些研究提供了对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的分子见解。 公共卫生相关性：革兰氏阴性细菌副溶血性弧菌是导致与食用受污染海鲜有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发生率与全球变暖引起的水温上升有关。海洋细菌副溶血性弧菌的基因组测序显示存在两个致病岛，编码III型分泌系统（T3 SS）和推定的效应器。在此，我们提出了具体的目的，通过确定三个已知的效应子的活性和宿主靶点，确定T3 SS 1分泌的其他效应子，并表征在感染期间被副溶血性弧菌破坏的宿主信号通路，来研究T3 SS 1诱导的多方面死亡。

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. PUBLIC HEALTH RELEVANCE: The gram-negative bacterium Vibrio parahaemolyticus is 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. Genomic sequencing of the marine bacterium V. parahaemolyticus revealed the existence of two pathogenicity islands that encode both a type III secretion system (T3SS) and putative effectors. 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.