Listeria monocytogenes physiology and host pathogen interactions

 描述（由申请方提供）：单核细胞增生李斯特菌是一种革兰氏阳性、机会性、胞内细菌病原体，可引起食源性疾病。鉴于其良好的特征感染周期和遗传的顺从性，L。单核细胞增多症提供了一个强有力的工具来询问细胞内细菌发病机理和宿主对细胞内病原体入侵的免疫应答的基本方面。以前已经证明L.进入宿主细胞胞质溶胶的单核细胞增多症分泌信号传导核苷酸c-di-AMP，导致刺激宿主IFN-γ产生。我们的初步研究已经揭示了c-di-AMP信号传导在细菌在肉汤中和宿主内生长的能力中的重要作用。此外，有证据表明c-di-AMP可能具有超出受感染宿主细胞的IFN-γ诱导的功能性后果。利用蛋白质组学和遗传学研究，我们已经确定了新的细菌和宿主途径，可能介导与这种独特的细菌信号分子相关的许多表型。在目的I中，我们建议探索由c-di-AMP调节的细菌小RNA的作用，并为李斯特菌的毒力所需。在目的II中，我们将表征三个c-di-AMP结合蛋白在介导信号转导中的作用。在最后的目标，我们将表征的影响c-di-AMP结合到一种新的宿主蛋白质，并阐明这些相互作用对感染的结果的影响。这些研究将共同定义c-di-AMP信号传导的分子机制，其介导该细胞内细菌感染期间宿主病原体相互作用。

 DESCRIPTION (provided by applicant): Listeria monocytogenes is a gram-positive, opportunistic, intracellular bacterial pathogen that causes food borne illness. Given its well-characterized infection cycle and genetic amenability, L. monocytogenes provides a powerful tool to interrogate the fundamental aspects of intracellular bacterial pathogenesis and the host immune response to invasion by intracellular pathogens. It has previously been demonstrated that L. monocytogenes that enter into the host cell cytosol secrete a signaling nucleotide, c-di-AMP, resulting in stimulation of host IFN-ß production. Our preliminary studies have uncovered important roles for c-di-AMP signaling in the ability of the bacterium to grow in broth and within the host. Furthermore, evidence suggests c-di-AMP may have functional consequences beyond IFN-ß induction by the infected host cell. Using proteomics and genetic studies we have identified novel bacterial and host pathways that may mediate the numerous phenotypes associated with this unique bacterial signaling molecule. In Aim I, we propose to explore the role of a bacterial small RNA regulated by c-di-AMP and required for Listeria virulence. In Aim II, we will characterize the role of three c-di-AMP binding proteins in mediating signal transduction. In the final aim, we will characterize the effects of c-di-AMP binding to a novel host protein and elucidate the effects of these interactions on the outcome of infection. Together these studies will define the molecular mechanisms of c-di-AMP signaling that mediate host pathogen interactions during infection by this intracellular bacterium.