Molecular and cellular characterization of host response pathways triggered by va

描述（由申请人提供）：我的研究目标是成为一名独立的研究者，领导一个研究小组，旨在了解宿主对空泡病原体的免疫。为此，我将呼吸道病原体嗜肺军团菌作为模型生物来了解病原体的免疫检测和随后的感染控制。在宿主细胞感染后，嗜肺乳杆菌能够阻止其转运到溶酶体，并将其液泡重塑为内质网衍生的室，以支持细菌复制。为了实现这一点，嗜肺乳杆菌利用IV型分泌系统（T4SS）将细菌效应物转运到宿主细胞中。我们发现宿主能够区分有毒性和无毒性的细菌。我们已经确定宿主MAPK通路仅在表达功能性T4SS的毒力细菌时激活，从而导致促炎细胞因子反应增加。这种依赖t4ss的宿主反应不同于TLR、Nod1、Nod2和炎性小体信号。然而，对于触发这种反应的细菌因子的身份以及这种途径如何促进免疫基因表达和随后对体内细菌感染的控制，人们知之甚少。将采用多学科的方法来回答这些问题。在目标1中，我将鉴定和表征t4ss依赖性宿主MAP激酶激活所需的细菌成分。在Aim 2中，我将识别和表征tlr依赖性和t4ss依赖性信号对免疫基因表达的贡献。最后，在Aim 3中，我将剖析各种细胞类型对嗜肺乳杆菌的先天免疫检测和随后的感染控制的贡献。在指导阶段，Aim 1的完成将提供一系列相对简单的实验以及基于筛选的方法，这些方法将产生可在独立阶段进行的候选细菌。此外，将产生Aim 3中描述的细菌菌株，并开始Aim 3的小鼠育种。在独立阶段，目标2和3涉及分子免疫学和体内感染模型将继续进行。这些研究将为进一步研究了解宿主对空泡病原体的反应提供坚实的基础，这将在我职业生涯的独立阶段进行。7. 了解宿主对呼吸道病原体嗜肺乳杆菌的反应将促进我们对细菌毒力的理解，以及先天免疫系统如何区分有毒和无毒细菌并启动抗菌免疫。这将最终有助于设计有效的抗菌疗法和疫苗。

DESCRIPTION (provided by applicant): 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. 7. Project narrative Understanding host responses to the respiratory pathogen L. pneumophila will advance our understanding of bacterial virulence and how the innate immune system distinguishes between virulent and avirulent bacteria and initiates antimicrobial immunity. This will ultimately aid in the design of effective antimicrobial therapies and vaccines.