Towards a molecular understanding of persistent tuberculosis infection

摘要 结核分枝杆菌（Mtb）仍然是由于传染病导致死亡的主要原因， 估计会感染全球三分之一的人口结核病（TB）是一种慢性、进行性疾病， 最初感染后的潜伏期。在大多数情况下，宿主免疫系统能够抑制， 不能消除结核分枝杆菌，导致终身感染。结核杆菌感染可以用抗生素治疗。但不同于 大多数其他细菌感染，有效的结核病治疗需要四种药物的组合， 最少六个月。这种漫长的治疗方案是有效控制结核病的关键障碍， 这被认为是由于在感染过程中出现的耐药杆菌的存在所必需的。这些 综合能力：1）面对强大的细胞介导的免疫力，坚持下去，并维持慢性感染; 2)耐受长时间暴露于致命浓度的抗生素，是持续全球成功的核心 这种病原体。由于与传统结核分枝杆菌遗传学相关的困难， 这些现象的根本原因在很大程度上仍未得到探索。为了弥补这一知识差距，我最近开发了 CRISPR干扰（CRISPRi）平台，以加速Mtb发病机制的遗传询问。这里我 建议利用这一变革性的新工具来确定持续性结核病感染的遗传基础。 具体来说，我将在结核病小鼠模型中进行动力学遗传学筛选，以确定细菌 决定因素，使慢性结核病感染。这些基因的后续功能表征将 确定其作用机制，从而揭示支持慢性结核病的分子结构。在 此外，有充分的文献记载，宿主感染的应激可诱导Mtb的抗生素耐受性。这里我 将检验一个假设，即大量扩增的神秘基因家族，即毒素-抗毒素， 通过趋异的严格反应来介导Mtb的抗生素耐受性。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， 知识和技术能力。此外，这项工作将作为知识基础， 开发新的结核病疗法，能够缩短疗程，改善对结核病的控制， 流行病

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.