BACTERIAL INTERACTIONS WITH THE BLADDER MUCOSA

描述(改编自应用摘要)：这是一项关于宿主的研究- 病原体在分子水平上的相互作用，特别是 细菌附着于宿主上皮细胞的结构与功能关系 细胞。尿路感染(UTI)影响着世界上很大一部分地区 并造成了严重的发病率和高昂的医疗费用。 大肠埃希氏菌是大多数尿路感染的病原体，包括 膀胱炎。肠杆菌科的其他成员，包括 克雷伯氏菌和丝裂变形杆菌，以及革兰氏阳性菌， 包括腐生葡萄球菌和机会性肠球菌， 也与尿路感染有关。作为病原体，这些不同的细菌 必须首先附着在尿路内的宿主粘膜表面。如果没有 这些病原体能够特异性地附着在宿主组织上， 很容易从寄主中驱逐出去，不会发生疾病。细菌 附着会引发细菌和细菌之间的分子串扰 可以直接影响感染过程的宿主细胞。虚拟 所有致尿路病原性大肠杆菌菌株和大多数 肠杆菌科编码丝状表面黏附细胞器 被称为类型1菌毛。这些结构可以介导细菌附着到 膀胱上皮细胞通过与宿主受体复合体相互作用包括 被称为尿板蛋白的完整的膜蛋白。候选人提议 以1型纤毛致尿路致病性大肠杆菌为模型研究其结构 细菌附着的基础和细菌附着的功能后果 附件事件。I型菌毛和I型菌毛相互作用的特性 将检查Uroplakin受体复合体。此外，细菌和 作为细菌黏附的结果发挥作用的宿主因素 对尿路感染发病机制的影响将从细胞和 分子水平。这项工作将有助于加深对致病机理的理解 尿路内和微生物进入的其他部位的过程 并将促进新的抗菌疗法的开发和 疫苗。具体目标是： 1.研究1型菌毛与尿路蛋白受体的相互作用 包覆在膀胱腔表面的复合体。突变分析 重组Uroplakin蛋白复合体和1型菌毛 生化、显微和结晶学技术将提供 对宿主-病原体相互作用的详细洞察 泌尿系致病大肠杆菌尿路感染的建立。 2.探讨致尿系致病菌致病因子及致病机制。 大肠杆菌在以下情况下入侵、传播并持续存在于膀胱内 由1型菌毛介导的初始依恋事件。有没有可能 在某些情况下，反复尿路感染可能是一种挥之不去的慢性尿路感染的表现 将对感染情况进行检测。 3.阐明宿主对尿路致病性大肠杆菌的反应，包括 鉴定和表征先天和适应性寄主防御系统 具有限制和清除尿路中入侵细菌的功能。细胞 培养系统和小鼠膀胱炎模型将被用来描绘生命 一种有效的宿主对1型纤毛E. Coli.

DESCRIPTION (adapted from application abstract): This is a study of host- pathogen interactions at the molecular level, specifically the structural functional relationship of bacterial attachment to host epithelial cells. Urinary tract infections (UTIs) affect a large proportion of the world population and account for significant morbidity and high medical costs. Escherichia coli is the etiologic agent in the majority of all UTIs, including cyctitis. Other members of the Enterobacteriaceae family, including Klebsiella species and Proteus mitabilis, and Gram-positive organisms, including Staphylococcus saprophyticus and opportunistic enterococci species, are also associated with UTIs. To act as pathogens, these various bacteria must first adhere to host mucosal surfaces within the urinary tract. Without the ability to specifically adhere to host tissues, these pathogens would be readily expelled from the host and disease would not occur. Bacterial attachment can initiate a cascade of molecular crosstalk between bacterial and host cells that can directly influence the course of an infection. Virtually all uropathogenic strains of E. coli and most members of the Enterobacteriaceae family encode filamentous surface adhesive organelles called type 1 pili. These structures can mediate bacterial attachment to bladder epithelial cells by interacting with host receptor complexes comprised of integral membrane proteins known as uroplakins. The candidate proposes to use type 1-piliated uropathogenic E. coli as a model to study the structural basis of bacterial attachment and the functional consequences of the attachment event. The specifics of the interactions between type 1 pili and uroplakin receptor complexes will be examined. In addition, the bacterial and host factors that come into play as a consequence of bacterial adherence and influence the pathogenesis of UTIs will be analyzed at both the cellular and molecular level. This work will lead to enhanced understanding of pathogenic processes both within the urinary tract and at other sites of microbial entry and will facilitate the development of novel antimicrobial therapeutics and vaccines. The specific aims are to: 1.Characterize interactions between type 1 pili and the uroplakin receptor complexes that coat the lumenal surface of the bladder. Mutational analysis of recombinant uroplakin protein complexes and of type 1 pili along with biochemical, microscopic, and crystallographic techniques will provide detailed insight into the host-pathogen interactions involved in the establishment of UTIs by uropathogenic E. coli. 2.Investigate virulence factors and mechanisms that enable uropathogenic E. coli to invade, disseminate, and persist within the bladder following the initial attachment event mediated by type 1 pili. The possibility that recurrent UTIs may, in some cases, be a manifestation of a lingering chronic infection will be tested. 3.Elucidate host responses to uropathogenic E. coli, including the identification and characterization of innate and adaptive host defenses that function to limit and clear invading bacteria from the urinary tract. Cell culture systems and a murine cystitis model will be used to delineate vital constituents of an effective host response to infection by type 1-piliated E. coli.