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发展计划，以鉴定和表征铜绿假单胞菌III型分泌系统的小分子抑制剂。长期目标是建立一个高效和资金充足的研究项目，利用本提案中概述的抑制剂来研究细菌病原体和宿主细胞的相互作用。铜绿假单胞菌是一种机会性病原体，是革兰氏阴性医院感染的主要原因。导致这种细菌毒性的一个因素是III型分泌系统。III型分泌系统是由20多种蛋白质组成的复合物，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。铜绿假单胞菌提供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有，包括耶尔森氏菌、沙门氏菌、志贺氏菌、肠致病性大肠杆菌、衣原体等。这种保守系统的普遍存在表明III型分泌是抑制这些细菌病原体感染的理想靶点。该提案旨在通过高通量测定鉴定小分子抑制剂，以测量宿主细胞对铜绿假单胞菌感染的保护作用。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允许识别更有效的抑制剂。抑制剂在III型注射途径上的生物学特异性将在利用III型分泌系统的其他病原体中进行测试。此外，通过识别每一类抑制剂的遗传靶点，将使抑制剂与III型分泌成分之间建立直接联系。本提案中生成的工具可用于解剖利用III型分泌物建立感染的许多细菌病原体之间共享或不同的生物学步骤。此外，本研究中发现的小分子抑制剂可作为开发治疗药物的起点，用于抑制利用III型分泌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.