Small molecule inhibitors of bacterial secretion system

描述(由申请人提供)：本申请描述了一个为期两年的研究学者开发计划，以识别和表征铜绿假单胞菌III型分泌系统的小分子抑制剂。长期目标是利用这项提案中概述的抑制剂，在细菌病原体和宿主细胞的相互作用方面建立一个高生产率和资金充足的研究计划。铜绿假单胞菌是一种条件致病菌，是革兰氏阴性菌医院感染的主要原因。导致这种细菌毒力的一个因素是III型分泌系统。III型分泌系统是一个由二十多种蛋白质组成的复合体，它允许将称为效应分子的蛋白质直接从细菌细胞质输送到真核宿主的细胞质中。铜绿假单胞菌产生两种高度细胞毒性效应分子：exOS和exoU。这种毒素传递机制在许多细菌病原体中都是相同的，包括耶尔森氏菌、沙门氏菌、志贺氏菌、肠源性大肠杆菌、衣原体和许多其他细菌。这一保守系统的流行表明，III型分泌物是预防这些细菌病原体感染的理想靶点。这项建议旨在通过高通量检测宿主细胞对铜绿假单胞菌感染的保护作用来确定小分子抑制剂。保护性化合物将根据III型注射途径中的抑制步骤进行分类。与原始保护性化合物相关的分子将有助于识别更有效的抑制剂。III型注射途径上的抑制剂的生物学特异性将在其他利用III型分泌系统的病原体中进行测试。此外，通过确定每类抑制物的遗传靶标，将在抑制物和III型分泌物成分之间建立直接联系。这一建议中产生的工具可用于剖析一些利用III型分泌物来确定感染的细菌病原体之间共有或不同的生物学步骤。此外，本建议中确定的小分子抑制剂可作为开发治疗药物的起点，以抑制由利用III型分泌物的革兰氏阴性病原体引起的细菌感染。

DESCRIPTION (provided by applicant): This application describes a two-year research scholar development program to identify and characterize small molecular inhibitors of Pseudomonas aeruginosa type III secretion system. The long-term goal is to establish a highly productive and well funded research program in the interaction of bacterial pathogens and host cells utilizing the inhibitors outlined in this proposal. P. aeruginosa is an opportunistic pathogen that is the leading cause of Gram-negative nosocomial infections. One factor that contributes to the virulence of this bacterium is the type III secretion system. Type III secretion system is a complex of over twenty proteins that allows for delivery of proteins called effector molecules directly from the bacterial cytoplasm into the cytoplasm of the eukaryotic host. P. aeruginosa delivers two highly cytotoxic effector molecules, ExoS and ExoU. This mechanism of toxin delivery is shared among many bacterial pathogens including Yersinia, Salmonella, Shigella, enteropathogenic E. coli, Chlamydia and many others. The prevalence of this conserved system suggests that type III secretion is an ideal target for inhibition to prevent infection by these bacterial pathogens. This proposal aims to identify small molecular inhibitors by a high-throughput assay that measures protection of host cells to infection by P. aeruginosa. Protective compounds will be classified by the inhibitory step in the type III injection pathway. Related molecules to the original protective compounds will allow identification of more potent inhibitors. The biological specificity of the inhibitors on the type III injection pathway will be tested in other pathogens that utilize type III secretion systems. Furthermore, a direct link between the inhibitor and type III secretion component will be made by identification of the genetic target of each class of inhibitors. The tools generated in this proposal can be used to dissect biological steps that are shared or distinct between a number of bacterial pathogens that utilize type III secretion to establish infections. Furthermore, the small molecule inhibitors identified in this proposal may be used as a starting point for the development of therapeutics to inhibit bacterial infection caused by Gram-negative pathogens that utilize type III secretion.