Towards a molecular understanding of persistent tuberculosis infection

摘要 结核分枝杆菌(结核分枝杆菌)仍然是传染病导致死亡的主要原因， 据估计感染了世界三分之一的地区。结核病(TB)是一种慢性、进展性疾病，通常具有长期的 初次感染后的潜伏期。在大多数情况下，宿主免疫系统能够抑制 没有消灭结核分枝杆菌，导致终身感染。结核分枝杆菌感染可以用抗生素治疗。然而，不同于 大多数其他细菌感染，有效的结核病治疗需要四种药物的联合服用 至少六个月。这一漫长的治疗方案是有效控制结核病的关键障碍，而且 被认为是由于感染期间出现的耐抗生素杆菌的存在而必需的。这些 综合能力：1)在强大的细胞介导的免疫面前坚持，并持续慢性感染；以及 2)容忍长期暴露于致命浓度的抗生素，是继续取得全球成功的核心 这种病原体的。由于与传统结核分枝杆菌遗传学相关的困难，其生物学机制 支撑这些现象的因素在很大程度上仍未得到探索。为了缩小这一知识鸿沟，我最近开发了 CRISPR干扰(CRISPRi)平台加速结核分枝杆菌发病机制的遗传询问。在这里，我 建议利用这一变革性的新工具来确定持续结核分枝杆菌感染的遗传基础。 具体地说，我将在结核病的小鼠模型中进行动态遗传学筛查，以确定细菌 导致慢性结核分枝杆菌感染的决定因素。随后对这些基因的功能特征将 确定它们的作用机制，从而揭示支持慢性结核病的分子结构。在……里面 此外，宿主感染的应激反应可以诱导结核分枝杆菌对抗生素的耐受。在这里，我 将检验这样一种假设，即大规模扩张和神秘的基因家族，即毒素-抗毒素，起作用 通过一种不同的严格反应来调节结核分枝杆菌的抗生素耐药性。我预计这些集体 这些发现将通过垂直推进我们的科学研究，消除该领域取得进展的重要障碍 知识和技术能力。此外，这项工作将成为 能够缩短疗程和改善控制的新型结核病疗法的开发 大流行。

ABSTRACT Mycobacterium tuberculosis (Mtb) remains the leading cause of death due to infectious disease and is estimated to infect one-third of the world. Tuberculosis (TB) is a chronic, progressive disease, often with a long period of latency following initial infection. In most cases, the host immune system is capable of restraining but not eliminating Mtb, leading to lifelong infection. Mtb infection can be treated with antibiotics. However, unlike most other bacterial infections, effective TB treatment requires a combination of four drugs taken for a minimum of six months. This lengthy treatment regimen is a critical barrier to effective TB control, and is thought to be necessitated by the presence of antibiotic-tolerant bacilli that arise during infection. These combined abilities: 1) to persist in the face of strong, cell-mediated immunity and sustain chronic infection; and 2) tolerate prolonged exposure to lethal concentrations of antibiotic, are central to the continued global success of this pathogen. Due to the difficulties associated with traditional Mtb genetics, the biological mechanisms underpinning these phenomena remain largely unexplored. To close this knowledge gap, I recently developed a CRISPR interference (CRISPRi) platform to accelerate the genetic interrogation of Mtb pathogenesis. Here, I propose to leverage this transformative new tool to define the genetic basis for persistent Mtb infection. Specifically, I will perform a kinetic-genetic screen in a murine model of TB to identify the bacterial determinants that enable chronic Mtb infection. Subsequent functional characterization of these genes will define their mechanisms of action, thereby revealing the molecular architecture that supports chronic TB. In addition, it is well documented that the stress of host infection can induce antibiotic tolerance in Mtb. Here, I will test the hypothesis that the massively expanded and enigmatic gene family, the toxin-antitoxins, function through a divergent stringent response to mediate antibiotic tolerance in Mtb. I anticipate that these collective findings will remove important roadblocks to progress in the field by vertically advancing our scientific knowledge and technical capability. Furthermore, this work will serve as an intellectual foundation for the development of novel TB therapies capable of shortening the course of treatment and improving control of this pandemic.