Mechanisms of Enteropathogenic E. coli Effects on Polarity and Tight Junctions

肠病性大肠杆菌对极性和紧密连接影响的机制

• 批准号: 8604446
• 负责人: Gail A Hecht
• 金额: $ 30.02万
• 依托单位: LOYOLA UNIVERSITY CHICAGO
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-10 至 2017-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8604446
• 关键词: Mechanisms; Enteropathogenic; E.; coli; Effects

DESCRIPTION (provided by applicant): Enteropathogenic E. coli (EPEC) is an important human bacterial pathogen that infects primarily infants in developing countries causing significant morbidity and mortality from diarrhea. EPEC pathogenesis is dependent on the injection of several bacterial effector molecules into host cells by a type III secretion system. EPEC effectors have a multitude of host cell targets. While recent studies focused on single effector proteins have revealed intriguing biochemical data, they have not shed light on the mechanisms by which downstream intestinal physiology is perturbed. Several EPEC effectors contribute to tight junction (TJ) disruption but the mechanisms and cooperative interactions are not known. TJ formation and maintenance in intestinal epithelial cells is dependent on physical and functional interactions between the Par and Crumbs polarity complexes. EPEC effectors may interfere with this process. The long-term goal of this proposal is to enhance our understanding of how multiple EPEC effectors coordinate to perturb intestinal epithelial function, particularly TJ regulation. Recognition of the interdependent relationships between EPEC effectors underscores the need for novel and comprehensive investigative approaches to define the complex mechanisms underlying EPEC pathogenesis. The objective of this proposal is to elucidate the mechanisms by which specific EPEC effectors cooperate to perturb key host intestinal epithelial physiologic endpoints that underlie pathogenesis. The central hypothesis is that EPEC effectors target, in a coordinated fashion, the Par and Crumbs polarity complexes ultimately disrupting TJ structure and barrier function. In vitro infection and transfection models as well as in vivo models will be used to address the hypothesis. Molecular, cellular, microbiological, and physiological approaches will be coupled with state-of-the-art microscopic techniques to achieve the stated goals. The rationale for the proposed research is that the identification of mechanisms by which pathogenic bacterial proteins hijack host cell regulatory controls to alter physiology will guide the development of novel strategies aimed at preserving host functions. The realization that bacterial effectors cooperate highlights the need for expanded efforts toward holistic approaches that examine the interplay between multiple effectors in executing a common goal. The following Specific Aims will address the hypothesis: 1. Define the mechanisms by which Map, EspG, and EspF cooperate to disrupt Par polarity complex. 2. Determine if Map, EspG and EspF disrupt TJ structure/function by targeting cell polarity complexes. 3. Investigate the interdependence of key EPEC effector molecules on disruption of epithelial polarity complexes and TJs using a multicellular and in vivo model of infection.

性状（由申请方提供）：肠致病性大肠杆菌。大肠杆菌（EPEC）是一种重要的人类细菌病原体，其主要感染发展中国家的婴儿，导致腹泻的显著发病率和死亡率。EPEC的发病机制依赖于通过III型分泌系统将几种细菌效应分子注射到宿主细胞中。EPEC效应子具有多种宿主细胞靶标。虽然最近的研究集中在单一效应蛋白揭示了有趣的生化数据，但它们并没有阐明下游肠道生理学受到干扰的机制。一些EPEC效应器有助于紧密连接（TJ）的破坏，但机制和合作的相互作用是未知的。TJ在肠上皮细胞中的形成和维持依赖于Par和Crumbs极性复合物之间的物理和功能相互作用。EPEC效应物可能会干扰这一过程。该提案的长期目标是提高我们对多个EPEC效应器如何协调干扰肠上皮功能，特别是TJ调节的理解。认识到EPEC效应子之间的相互依赖关系，强调了需要新的和全面的调查方法，以确定EPEC发病机制的复杂机制。本提案的目的是阐明特定的EPEC效应器合作干扰宿主肠道上皮细胞的关键生理终点，发病机制的基础机制。核心假设是EPEC效应物以协调的方式靶向Par和Crumbs极性复合物，最终破坏TJ结构和屏障功能。体外感染和转染模型 以及体内模型将被用于解决该假设。分子、细胞、微生物和生理学方法将与最先进的显微技术相结合，以实现既定目标。拟议研究的基本原理是，病原性细菌蛋白质劫持宿主细胞调节控制以改变生理学的机制的鉴定将指导旨在保护宿主功能的新策略的开发。细菌效应子合作的认识突出了需要扩大努力，以全面的方法，检查多个效应子之间的相互作用，在执行一个共同的目标。以下具体目标将解决假设：1。定义Map、EspG和EspF合作破坏Par极性复合物的机制。2.确定Map、EspG和EspF是否通过靶向细胞极性复合物破坏TJ结构/功能。3.使用多细胞和体内感染模型研究关键EPEC效应分子对上皮极性复合物和TJ破坏的相互依赖性。