Molecular and cellular characterization of host response pathways triggered by va

6.项目总结/摘要 我的研究目标是成为一名独立的调查员，领导一个研究小组， 了解宿主对空泡病原体的免疫力。为此，我用呼吸道病原体 嗜肺军团菌作为模式生物，以了解病原体的免疫检测和随后的 控制感染。感染宿主细胞后，L.嗜肺菌能够阻止其转运至溶酶体，并且 将其空泡改造成支持细菌复制的内质网衍生的隔室。到 做到这一点，L。嗜肺菌利用IV型分泌系统（T4 SS）来移位细菌效应子 进入宿主细胞我们发现宿主能够区分有毒和无毒的细菌。 我们已经确定了宿主MAPK途径仅在对表达功能性MAPK的毒性细菌应答时激活。 T4 SS导致促炎细胞因子反应增加。这种依赖T4 SS的宿主反应是 与TLR、Nod 1、Nod 2和炎性体信号传导不同。然而，人们对这位 细菌因素触发这种反应，以及这种途径如何有助于免疫基因表达， 随后控制体内细菌感染。将采取多学科方法来回答这些问题 问题.在目标1中，我将鉴定和表征T4 SS依赖性 激活宿主MAP激酶。在目标2中，我将识别和描述TLR依赖性的贡献。 和T4 SS依赖性信号传导对免疫基因表达的影响。最后，在目标3中，我将剖析 各种细胞类型的先天性免疫检测L.嗜肺菌和随后的感染控制。 在指导阶段，完成目标1将提供一系列相对简单的实验 以及基于筛选的方法，这些方法将产生细菌候选物， 独立阶段。此外，将产生目标3中所述的细菌菌株，并进行小鼠育种， 目标3将启动。在独立阶段，目标2和3涉及分子免疫学和体内 将继续研究感染模型。这些研究将为进一步研究提供坚实的基础， 了解宿主对液泡病原体的反应，这将在我的独立阶段进行。 事业

6. Project Summary/Abstract My research goal is to become an independent investigator that heads a research group aimed at understanding host immunity against vacuolar pathogens. To this end, I am using the respiratory pathogen Legionella pneumophila as a model organism to understand immune detection of pathogens and subsequent control of infection. Upon host cell infection, L. pneumophila is able to prevent its transport to lysosomes, and remodels its vacuole into an endoplasmic reticulum-derived compartment that supports bacterial replication. To accomplish this, L. pneumophila utilizes a type IV secretion system (T4SS) to translocate bacterial effectors into the host cell. We have found that the host is able to discriminate between virulent and avirulent bacteria. We have identified host MAPK pathways activated only in response to virulent bacteria expressing a functional T4SS that result in an increased proinflammatory cytokine response. This T4SS-dependent host response is distinct from TLR, Nod1, Nod2, and inflammasome signaling. However, little is known about the identity of the bacterial factors that trigger this response and how this pathway contributes to immune gene expression and subsequent control of bacterial infection in vivo. A multi-disciplinary approach will be taken to answer these questions. In Aim 1, I will identify and characterize the bacterial components required for T4SS-dependent activation of host MAP kinases. In Aim 2, I will identify and characterize the contributions of TLR-dependent and T4SS-dependent signaling to immune gene expression. Finally, in Aim 3, I will dissect the contributions of various cell types to the innate immune detection of L. pneumophila and subsequent control of infection. During the mentored phase, completion of Aim 1 will provide a series of relatively straightforward experiments as well as screen-based approaches that will yield bacterial candidates that can be pursued during the independent phase. Additionally, bacterial strains described in Aim 3 will be generated and mouse breeding for Aim 3 will be started. During the independent phase, Aims 2 and 3 involving molecular immunology and in vivo infection models will be pursued. These studies will provide a solid foundation for further investigations into understanding host responses to vacuolar pathogens that will be pursued during the independent phase of my career.