尿道致病性大肠杆菌新型双组份信号系统KguS/KguR控制的毒力岛的调控机制、生物学功能和致病机制

Urinary tract infection (UTI) is the most frequently diagnosed urologic disease which causes several millions morbidity and cost the healthcare system 1.6 billion per year.Uropathogenic E. coli (UPEC) is responsible for 90% of community-acquired nosocomial urinary tract infections. No matter how we measure the costs and negative health impacts of urinary tract infections caused by UPEC, they are unacceptably high. Thus, control of UPEC-caused diseases is highly desirable. Development of effective control strategies for UPEC infection will require thorough understanding of UPEC's pathogenic mechanisms. In this regard, the impact of metabolism on UPEC virulence is underappreciated. UPEC's physiologic and metabolic adaptive mechanisms, especially those associated with adaptation to the kidney, since the kidney provides UPEC with several unique carbon sources, have been largely overlooked to date. Therefore, the studies proposed here are intended to fill a critical gap in our understanding of UPEC pathogenesis. Our preliminary data strongly suggest that a'UPEC-associated' novel two component signaling system (TCS) KguS/KguR controls UPEC adaptation to renal physiology. In this proposed study, we will determine the regulatory mechanisms, biological function, and pathogenic role of the novel TCS controlled genomic island using cutting-edge technologies such as laser capture microdissection, protein pull-down and in vitro transcription technologies. This study will elucidate UPEC pathogenesis and adaptive mechanisms to the kidney and fill the knowledge gap.

尿道感染是人类世界范围内最普遍的细菌感染之一，造成每年约700万人患病及数十六亿美元的医疗支出。尿路感染最常见的病因是尿道致病性大肠杆菌（UPEC），占社区获得性尿路感染的90%。因此，控制UPEC感染迫在眉睫。有效控制UPEC需全面了解其致病机制。首当其冲的问题是UPEC的代谢对其毒力影响被严重低估了。肾脏为UPEC提供了几种独特的碳源，所以国内外高度关注UPEC对肾脏生理代谢环境的分子适应机制。我们前期研究发现一个UPEC关联的新型双组份信号系统KguS/KguR并证实它与UPEC适应肾脏代谢环境有关。本研究拟利用激光捕获显微切割、信号转导、蛋白质相互作用、转录调控等先进技术进一步研究新型双组份信号系统kguS/kguR控制的毒力岛的调控机制、生物学功能及致病性机理，将首次阐明UPEC的肾脏适应机制和致病机制，填补国际空白。

尿道感染是人常见的细菌性感染，尿道致病性大肠杆菌（UPEC）是尿道感染最常见的病原体，深入了解UPEC的致病机制对有效防控尿道感染具有重要意义。本研究在前期发现UPEC的新型双组份信号系统kguS/kguR并证实其生物学功能的基础上，进一步深入研究kguS/kguR控制的毒力岛的功能及其调控机制。首先构建了毒力岛各基因的基因缺失株或基因克隆表达株，通过体外有氧、厌氧培养测定基因缺失株的生长代谢特性，测定基因表达蛋白的酶学活性，在尿道感染动物模型上通过基因缺失株与野生株的竞争试验验证毒力岛基因的生物学功能及基因调控机制，通过体内和体外试验系统研究了c5032-5035、c5036-5037、c5032-5037、c5038、kgtP等毒力基因的功能，研究了σ54、rpoN、ArcA、FNR、CRP及RpoS对c5038、kgtP的调控机制。本研究初步阐明了UPEC的肾脏适应机制和致病机制，为UPEC新型诊断方法和防治药物研发奠定了基础。