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: 8417114
• 负责人: Gail A Hecht
• 金额: $ 2.98万
• 依托单位: UNIVERSITY OF ILLINOIS AT 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 2013-03-05
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8417114
• 关键词: Address; Bacterial Proteins; Binding; Biochemical; Biological Assay; Cell Line; Cell Polarity; Cell physiology; Cells; Complex; Coupled; Cyst; Cytoplasm; Data; Developing Countries; Development; Diarrhea; Disease; Dissociation; Endocytosis; Epithelial; Epithelial Cells; Escherichia coli EHEC; Escherichia coli Infections; Escherichia coli Proteins; Event; Genes; Goals; Health; Human; In Vitro; Infant; Infection; Injection of therapeutic agent; Intestinal Content; Intestines; Investigation; Lateral; Light; Maintenance; Maps; Membrane; Microscopic; Modeling; Molecular; Morbidity - disease rate; Morphogenesis; Movement; Mus; Pathogenesis; Physiological; Physiology; Process; Proteins; Public Health; Regulation; Research; Role; Signal Transduction; Sorting - Cell Movement; Structure; Techniques; Therapeutic Intervention; Tight Junctions; Transfection; Translations; Type III Secretion System Pathway; United States; Work; enteropathogenic Escherichia coli; fascinate; foodborne outbreak; holistic approach; in vivo; in vivo Model; intestinal epithelium; migration; mortality; nexin; novel; novel strategies; occludin; overexpression; p21 activated kinase; pathogen; prevent; protein complex; protein protein interaction

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. PUBLIC HEALTH RELEVANCE: This work is relevant to public health because enteropathogenic E. coli (EPEC) is a cause of severe diarrheal disease and also serves as a model pathogen for enterohemorrhagic E. coli (EHEC), the cause of several recent food-borne outbreaks in the United States. EPEC causes diarrhea in part by injecting proteins into intestinal cells that destroy tight junctions (TJs), the structures that prevent the passage of noxious intestinal contents between the cells that line the intestine. Understanding how EPEC proteins work together to disrupt the structure and function of TJs will allow for the development of new strategies for preserving and restoring these important structures.

描述（由申请人提供）：肠致病性大肠杆菌（EPEC）是一种重要的人类细菌病原体，主要感染发展中国家的婴儿，引起腹泻的显著发病率和死亡率。EPEC的发病机制依赖于几种细菌效应分子通过III型分泌系统注射到宿主细胞中。EPEC效应物具有多种宿主细胞靶点。虽然最近的研究集中在单一效应蛋白上，揭示了有趣的生化数据，但它们并没有阐明下游肠道生理受到干扰的机制。几种EPEC效应物有助于紧密结（TJ）破坏，但机制和合作相互作用尚不清楚。肠上皮细胞中TJ的形成和维持依赖于Par和碎屑极性复合物之间的物理和功能相互作用。EPEC效应物可能干扰这一过程。本提案的长期目标是加强我们对多种EPEC效应物如何协调干扰肠上皮功能，特别是TJ调节的理解。认识到EPEC效应物之间的相互依赖关系，强调需要新的和全面的研究方法来定义EPEC发病机制的复杂机制。本研究的目的是阐明特定的EPEC效应物协同干扰宿主肠上皮生理终点的机制，这些生理终点是发病机制的基础。核心假设是EPEC效应物以协调的方式靶向Par和碎屑极性复合物，最终破坏TJ结构和势垒功能。体外感染和转染模型