Mtb strain-dependent mechanisms of pathogenesis in mouse models

结核病（TB）是一种高度异质性的人类疾病，在一些但不是所有人中发展， 吸入1-3支结核分枝杆菌（Mtb）感染性杆菌的个体。结核病可以 范围从轻度和自行消退的肺部疾病，到重度，或可以传播到 肺外部位。了解结核病发病机制的复杂性需要一个全面的 这是一种整合人类和动物模型研究的方法。尽管越来越多的证据表明 Mtb菌株依赖性因子驱动不同的感染结果， 对这些结果的管理知之甚少。在这个项目中，我们从临床结核菌株开始， 与不同的致病结果相关（例如，高度传播或播散性疾病） 或在核心A和项目A中鉴定的候选基因中含有修饰的突变株 1，鉴定与不同人类临床结果相关的Mtb菌株的多态性。 感染了这些临床或突变型结核分枝杆菌菌株的小鼠将用于研究它们如何在小鼠体内表达。 控制发病的三个不同阶段：1）在气溶胶部位建立感染 吸入，2）传播到远处，3）与宿主免疫的相互作用， 肺巨噬细胞群。这些研究将利用我们小组最近的进展， 小鼠TB模型，包括鉴定气溶胶Mtb感染后最早的细胞事件， 使用生理性超低剂量（ULD）感染模型跟踪Mtb传播，其中 用1- 3CFU的雾化Mtb感染小鼠，并评估配对的宿主和Mtb 转录组在不同的肺巨噬细胞类型。多参数共聚焦显微镜 先进的定量图像分析将用于确定这些结核分枝杆菌菌株- 依赖因子在感染部位形成免疫细胞相互作用。的总体目标 拟议的实验是深入了解发病机制的分子和细胞机制 在不同阶段的结核分枝杆菌感染，以告知新的主机和病原体的发展， 干预措施。

Tuberculosis (TB) is a highly heterogeneous human disease that develops in some, but not all, individuals who inhale 1-3 infectious bacilli of Mycobacterium tuberculosis (Mtb). TB disease can range from pulmonary disease that is mild and self-resolving, to severe, or can disseminate to extrapulmonary sites. Understanding the complexity of TB pathogenesis requires a holistic approach that integrates human and animal model studies. Although there is growing evidence that Mtb strain-dependent factors drive different infection outcomes, the in vivo mechanisms that govern these outcomes are poorly understood. In this project, we start with clinical Mtb strains associated with different pathogenic outcomes (e.g., high transmission or disseminated disease) or mutant strains harboring modifications in gene candidates, identified in Core A and Project 1, to identify polymorphisms in Mtb strains associated with distinct human clinical outcomes. Mice infected with these clinical or mutant Mtb strains will be used to investigate how they govern three distinct stages of pathogenesis: 1) establishing infection at the site of aerosol inhalation, 2) dissemination to distant sites, and 3) interactions with host immunity in distinct lung macrophage populations. These studies will leverage our group’s recent advances in mouse TB models, including identifying the earliest cellular events after aerosol Mtb infection, tracking Mtb dissemination using a physiologic, ultra low-dose (ULD) infection model in which mice are infected with 1-3 CFUs of aerosolized Mtb, and assessing paired host and Mtb transcriptomes in distinct pulmonary macrophage types. Multiparameter confocal microscopy and advanced quantitative image analysis will be used to determine how these Mtb strain- dependent factors shape immune cell interactions at infection sites. The overall goal of the proposed experiments is to gain insight into molecular and cellular mechanisms of pathogenesis at distinct stages of Mtb infection to inform development of novel host- and pathogen-directed interventions.