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 细菌与宿主上皮细胞粘附结构功能关系 细胞 尿路感染（UTI）影响着世界上很大一部分人 这是一个人口众多的国家，发病率高，医疗费用高。 大肠杆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 克雷伯氏菌属和变形杆菌属，以及革兰氏阳性微生物， 包括金黄色葡萄球菌和机会性肠球菌， 也与尿路感染有关。 作为病原体，这些细菌 必须首先粘附到泌尿道内的宿主粘膜表面。 没有 特异性粘附于宿主组织的能力，这些病原体将被 很容易从宿主体内排出，不会发生疾病。 细菌 附着可以引发细菌和细菌之间的分子串扰级联， 可以直接影响感染过程的宿主细胞。 几乎 所有泌尿系致病性E.大肠杆菌和大多数 肠杆菌科编码丝状表面粘附细胞器 称为1型皮利。 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物相互作用，所述宿主受体复合物包含 一种叫做uroplakins的膜蛋白。 候选人提议 使用1型-纤毛尿路致病性E.大肠杆菌作为模型来研究 细菌附着的基础和细菌附着的功能后果 依恋事件 1型皮利和 检查尿斑蛋白受体复合物。 此外，细菌和 作为细菌粘附的结果而发挥作用的宿主因素， 影响尿路感染的发病机制将在细胞和 分子水平。 这项工作将有助于提高对致病性 在泌尿道内和微生物进入的其他部位的过程 并将促进新型抗微生物治疗剂的开发， 疫苗。 具体目标是： 1.表征1型皮利和尿斑蛋白受体之间的相互作用 覆盖膀胱内腔表面的复合物。 突变分析 重组尿斑蛋白复合物和1型皮利沿着 生物化学、显微镜和晶体学技术将提供 详细了解宿主与病原体的相互作用， 尿路感染由尿路致病性E.杆菌 2.研究致病性大肠杆菌的毒力因子和致病机制。 大肠杆菌入侵，传播，并坚持在膀胱内以下 由1型皮利介导初始附着事件。 的可能性 在某些情况下，复发性尿路感染可能是一种挥之不去的慢性炎症的表现， 感染将被测试。 3.阐明宿主对尿路致病性E.大肠杆菌，包括 鉴定和表征先天和适应性宿主防御， 功能是限制和清除尿路中的侵入细菌。 细胞 培养系统和小鼠膀胱炎模型将用于描绘重要的 1型纤毛E. 杆菌

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.