The role of redox sensing in Listeria monocytogenes pathogenesis

项目摘要 单核细胞增生李斯特菌（Lm）致病机制的一个关键研究不足的部分是哺乳动物的定植 胆囊胆囊是几种肠道病原体的主要细菌储存库，包括Lm， 沙门氏菌和弯曲杆菌，并作为粪便分泌细菌的来源，这些细菌有可能 增加这些食源性病原体的传播。在这里，我们将剖析Lm增长的性质， 胆囊和确定细菌代谢和应激反应途径的殖民化的关键 小鼠胆囊。为此，我们提出了我们的新的离体Lm胆囊模型的初步数据， 使用来自非人灵长类动物（NHP）的器官进行定殖。这些结果为调查奠定了基础 转化为Lm在胆囊腔中复制所必需的特定基因和途径。这一目标 本研究的目的有三：（1）将胆囊定义为Lm的复制生态位。 为了做到这一点，我们将确定Lm在胆囊中的定位，并确定在胆囊中可用的代谢物。 胆囊腔(2)确定胆囊定植所需的Lm基因。在这里，荧光 报告菌株将被工程化以鉴定在胆囊中被激活的Lm信号通路 在感染期间。此外，我们将评估特定的Lm基因和途径在发病机制中的作用， 重点是胆囊定植。(3)确定免疫应答对Lm暴龙雷克斯感染的作用。 我们的方法在技术上是创新的，因为它利用了我们新的NHP胆囊定植模型 全面评估细菌基因在这个独特的生态位复制的重要性。这些研究的结果将 重要的是，他们将揭示细菌病原体如何在胆囊中复制，并有可能 发现治疗靶点以减少肠道病原体的定植和传播。

PROJECT SUMMARY A critically understudied part of Listeria monocytogenes (Lm) pathogenesis is colonization of the mammalian gallbladder. The gallbladder is the primary bacterial reservoir for several enteric pathogens, including Lm, Salmonella, and Campylobacter, and serves as the source of fecally secreted bacteria that has the potential to increase transmission of these foodborne pathogens. Here, we will dissect the nature of Lm growth in the gallbladder and identify the bacterial metabolic and stress response pathways critical for colonization of the murine gallbladder. To that end, we present preliminary data from our novel ex vivo model of Lm gallbladder colonization using organs from non-human primates (NHP). These results have set the stage for investigations into specific genes and pathways necessary for Lm replication in the gallbladder lumen. The objectives of this proposal will be accomplished with three Specific Aims: (1) Define the gallbladder as a replicative niche for Lm. To do this, we will determine the localization of Lm in the gallbladder and define the metabolites available in the gallbladder lumen. (2) Identify the Lm genes required for colonization of the gallbladder. Here, fluorescent reporter strains will be engineered to identify the Lm signaling pathways that are activated in the gallbladder during infection. Additionally, we will evaluate specific Lm genes and pathways for their roles in pathogenesis, with a focus on gallbladder colonization. (3) Determine the role of the immune response to Lm ∆rex infection. Our approach is technically innovative as it takes advantage of our novel model of NHP gallbladder colonization to globally assess bacterial genes important for replication in this unique niche. Results from these studies will be significant as they will uncover how bacterial pathogens replicate in the gallbladder and have the potential to uncover therapeutic targets to reduce colonization and spread of enteric pathogens.