STRUCTURAL GLYCOMICS OF THE E. COLI HOST-PATHOGEN INTERFACE

描述（由申请人提供）：尿路致病性大肠杆菌识别特异性宿主表位。大肠杆菌（UPEC）是引发尿路和肾脏感染的重要过程。这一过程通常由碳水化合物结合蛋白（凝集素）介导，称为粘附素，粘附素组装在称为皮利的毛发状细胞外附属物的尖端。粘附素FimH识别宿主尿斑蛋白上的单甘露糖和多甘露糖表位是尿路感染（UTI）的重要步骤，而PapG识别肾脏中的半乳糖是大肠杆菌（E.结肠肾盂肾炎。UPEC皮利的表达发生在菌毛操纵子上，其可通过编码引导组装平台、防止周质组装的伴侣蛋白、菌毛终止子、主要菌毛亚基、尖端接头亚基以及总是在操纵子末端的粘附素的一系列基因来鉴定。虽然fim和pap操纵子已被充分研究，但还有8个额外的UPEC菌毛操纵子，每个都有自己的粘附素。该建议利用人类聚糖阵列来确定这八种粘附素的碳水化合物特异性，以及用于推断这些粘附素可以识别哪些宿主组织的计算方法。一个平行的目标是确定这种基本的主机病原体识别事件的结构基础，每个粘附素使用高通量晶体学管道。最后一个关键因素是开发基于细胞的血凝试验，以验证粘附素碳水化合物的特异性及其结构基础。从长远来看，这项工作为开发针对特定粘附素的抗病毒疗法奠定了基础，类似于最近开发的一系列针对FimH的甘露糖苷类药物，以治疗尿路感染。 公共卫生相关性：大肠杆菌尿路感染是西方世界最常见的感染。仅占泌尿系致病性大肠杆菌总数的五分之一。被称为粘附素的大肠杆菌宿主识别蛋白已被充分研究，但这些蛋白可能是导致尿路和肾脏感染的重要因素。这项提议旨在确定这些研究不足的粘附素如何识别E.这为开发针对这种识别的治疗药物奠定了基础。

DESCRIPTION (provided by applicant): Recognition of specific host epitopes by uropathogenic E. coli (UPEC) is a process essential to initiating infection of the urinary tract and kidneys. This process is most often mediated by carbohydrate-binding proteins (lectins) called adhesins that are assembled at the tips of hairlike extracellular appendages called pili. Recognition of mono- and poly-mannose epitopes on host uroplakins by the adhesin FimH is an essential step in urinary tract infection (UTI), while recognition of galabiose in the kidney by PapG is essential to E. coli pyleonephritis. Expression of UPEC pili occurs from pilus operons, which are identifiable by a series of genes encoding an usher assembly platform, a chaperone to prevent periplasmic assembly, a pilus terminator, a major pilus subunit, tip adapter subunits and, invariably at the end of the operon, an adhesin. While the fim and pap operons are well-studied, there are eight additional UPEC pilus operons, each with its own adhesin. This proposal utilizes human glycan arrays to determine the carbohydrate specificity of these eight adhesins as well as a computational method for extrapolating which host tissues these adhesins may recognize. A parallel aim is to determine the structural basis of this fundamental host-pathogen recognition event for each adhesin using a high-throughput crystallography pipeline. A final key element is the development of cell-based hemagglutination assays for validation of adhesin carbohydrate specificity and its structural basis. Long-term, this work sets the stage for development of antivirulence therapies targeting specific adhesins, similar to the recently-developed set of mannoside drugs targeting FimH to cure urinary tract infection. PUBLIC HEALTH RELEVANCE: Escherichia coli urinary tract infection is the most common infection in the Western world. Only one-fifth of the total number of uropathogenic E. coli host-recognition proteins called adhesins are well studied, yet these proteins may represent essential factors in causing urinary tract and kidney infection. This proposal seeks define the molecular basis of how these understudied adhesins recognize E. coli's human host, setting the stage for development of therapeutic drugs that target this recognition.