Mechanistic aspects of integrin-mediated Yersinia uptake

描述（由申请人提供）： 微生物的致病性在很大程度上取决于与宿主细胞和组织相互作用以促进定植和存活的毒力因子。该提案的目的是更好地了解致病性耶尔森氏菌表达的毒力因子利用宿主细胞因子促进疾病的机制。由这些细菌产生的主要毒力因子之一是侵袭素，其通过结合宿主细胞表面上存在的β-1整联蛋白并促进肠上皮的侵袭而在致病性中起关键作用。该提议检验了宿主中特定的整合素依赖性信号网络被耶尔森氏菌靶向以促进入侵的假设。 尽管这些途径在最初的入侵过程中被激活，然而，它们在感染的后期被其他毒力因子的活性有效地破坏，从而允许病原体的细胞外生长。该假说的第二个方面是，整合素依赖性信号网络的组分最终克服了这些毒力因子的抑制作用，并促进了细菌从肠道中的清除。为解决这些假设，制定了以下具体目标： 目标1：使用体外细胞培养模型，我们建议调查的分子组织和调控的整合素依赖的信号网络建立在巨噬细胞在过程ofYersinia摄取。 目标二：与耶尔森氏菌致病性方面密切相关的整联蛋白依赖性信号传导途径的一个组分是Src家族激酶。本研究旨在利用Src基因敲除小鼠研究这些蛋白在耶尔森氏菌感染过程中的作用。 目标3：这些小鼠模型也将与一组在特定细胞粘附素中含有突变的耶尔森菌菌株一起使用，以探索耶尔森菌毒力因子和Src家族激酶在细菌入侵和定植过程中的功能关系。 这些研究的完成将有助于全面了解耶尔森氏菌致病性所涉及的宿主细胞和微生物机制，并在此过程中深入了解其他整合素依赖性途径。

DESCRIPTION (provided by applicant): Microbial pathogenicity is largely determined by virulence factors that interface with host cells and tissues to promote colonization and survival. The goal of this proposal is to develop a better understanding of the mechanisms through which virulence factors expressed by enteropathogenic Yersiniae utilize host cell factors to promote disease. One of the major virulence factors produced by these bacteria is invasin, which plays a crucial role in pathogenicity by binding to beta-1 integrins present on the surface of host cells and facilitating invasion of the intestinal epithelium. This proposal tests the hypothesis that specific integrin dependent signaling networks in the host are targeted by the Yersiniae to promote invasion. Whereas these pathways are activated during the initial invasion process, however, they are effectively subverted at later stages in infection by the activities of other virulence factors, thus allowing for extracellular growth of the pathogen. A second facet of this hypothesis is that components of integrin-dependent signaling networks eventually overcome the inhibitory actions of these virulence factors and facilitate clearance of the bacteria from the intestine. The following specific aims have been developed to address these hypotheses: Aim 1: Using in vitro cell culture models, we propose to investigate the molecular organization and regulation of integrin-dependent signaling networks established in macrophages during the course ofYersinia uptake. Aim 2: One component of integrin-dependent signaling pathways that has been strongly implicated in aspects of Yersinia pathogenicity is the Src family kinases. This aim will explore the function of these proteins in the course of Yersinia infection with the use of Src family knockout mice. Aim 3: These mouse models will also be used, together with a panel of Yersinia strains that contain mutations in specific cellular adhesins, to explore the functional relationship between Yersinia virulence factors and Src family kinases during the course of bacterial invasion and colonization. Completion of these studies will help to generate a comprehensive understanding of the host cell and microbial mechanisms involved in Yersinia pathogenicity and, in the process, provide insight into other integrin-dependent pathways.