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.

描述（由申请人提供）：肠病大肠杆菌（EPEC）是一种重要的人类细菌病原体，主要是在发展中国家感染婴儿的婴儿，导致腹泻的发病率明显和死亡率。 EPEC发病机理取决于通过III型分泌系统将几种细菌效应子分子注射到宿主细胞中。 EPEC效应子具有众多宿主细胞靶标。尽管最近针对单个效应蛋白的研究揭示了有趣的生化数据，但它们尚未阐明下游肠道生理的机制。几个EPEC效应子有助于紧密连接（TJ）破坏，但尚不清楚机制和合作相互作用。肠上皮细胞中的TJ形成和维护取决于PAR和Crumbs极性复合物之间的物理和功能相互作用。 EPEC效应子可能会干扰此过程。该提案的长期目标是增强我们对多个EPEC效应子如何协调肠道上皮功能，尤其是TJ调节的理解。对EPEC效应子之间相互依赖关系的认识强调了对定义EPEC发病机理基础的复杂机制的新颖和全面研究方法的需求。该提案的目的是阐明特定EPEC效应子与构成发病机理的基础的特定EPEC效应子合作与关键宿主肠上皮生理终点合作的机制。中心假设是EPEC效应子以协调的方式目标，PAR和Crumbs极性复合物最终破坏了TJ结构和屏障功能。体外感染和转染模型 以及体内模型将用于解决该假设。分子，细胞，微生物和生理方法将与最先进的显微镜技术结合，以实现所指出的目标。拟议的研究的基本原理是，鉴定致病细菌蛋白劫持宿主细胞调节控制以改变生理的机制将指导旨在维护宿主功能的新型策略的发展。认识到细菌效应子协作的认识表明，需要扩大努力，以研究整体方法，以检查多个效应子在执行共同目标时之间的相互作用。以下特定目的将解决以下假设：1。定义映射，ESPG和ESPF合作以破坏Parpality复合物的机制。 2。通过靶向细胞极性复合物来确定MAP，ESPG和ESPF是否破坏TJ结构/功能。 3。使用多细胞感染模型和体内模型，研究关键EPEC效应分子对上皮极性复合物和TJ的破坏的相互依赖性。