Genetic Requirements for the survival of Tubercle Bacilli in Nonhuman Primates

描述（由申请人提供）：结核（TB）是由结核分枝杆菌（Mtb）引起的全球性突发传染病。每年估计有800万人患结核病，约200万人死于结核病。加上艾滋病、耐药性的出现以及缺乏有效的抗结核药物和疫苗，这种情况进一步恶化。为了有效控制结核病，迫切需要新的药物和疫苗。这需要更好地了解结核分枝杆菌如何适应在感染的各个阶段不可避免地面临的各种环境条件。可以说，非人类灵长类动物（NHPs）是结核病关键方面的最佳模型。因此，分析结核分枝杆菌成功感染并在NHP肺部持续存在的机制将是非常有用的。我们研究了Mtb在NHP肺中生长/存活所必需的基因，实验暴露于Mtb转座子突变文库的高剂量气溶胶中。在这个急性结核模型中，33.13%的所有测试突变体在体内生长时被减毒，而小鼠模型中只有6%的突变体被减毒。在灵长类动物体内减毒的Mtb突变体参与脂质毒力因子的转运；细胞壁阿拉伯聚糖、肽聚糖、脂肪酸和聚酮的生物合成；DNA修复;固醇代谢与哺乳动物细胞进入（mce）。我们的研究强调了结核分枝杆菌感染的各种毒力机制，并克服了NHP肺部感染期间遇到的敌对环境。我们希望利用我们的能力来模拟人类结核病的不同临床阶段——急性、肺结核、慢性进展性结核病和NHPs中的潜伏性、无症状结核病——来研究结核分枝杆菌突变体的生长/存活表型。此外，我们希望利用NHP模型更好地了解两种对毒力和发病机制至关重要的结核分枝杆菌途径的作用。这些包括mce1/mce4操纵子，其成员在NHP肺中生长的突变体中被减弱；以及dos调控的成员，令人惊讶的是，尽管它们在潜伏期、持久性和抗缺氧防御中有明确的作用，但在NHP肺中并未减弱。

DESCRIPTION (provided by applicant): Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is a global infectious disease emergency. Each year an estimated 8 million people develop, and about two million people die of TB. Synergy with AIDS, the emergence of drug-resistance and the lack of effective anti-TB drugs and vaccines has worsened this situation. New drugs and vaccines are urgently needed to effectively control TB. This requires a better understanding of how Mtb adapts to a wide-variety of environmental conditions, inevitably faced by it during the various stages of infection. Nonhuman Primates (NHPs), arguably, best model critical aspects of TB. Analysis of the mechanisms employed by Mtb to successfully infect and persist in NHP lungs would therefore be very useful. We studied genes essential for growth/survival of Mtb in the NHP lungs experimentally exposed to high doses of aerosols of an Mtb transposon mutant library. In this acute model of TB, 33.13% of all tested mutants were attenuated for in-vivo growth compared to the mouse model where only ~6% of all mutants are attenuated. The Mtb mutants attenuated for in-vivo survival in primates were involved in the transport of lipid virulence factors; biosynthesis of cell-wall arabinan and peptidoglycan, fatty-acids and polyketides; DNA repair; sterol metabolism and mammalian cell-entry (mce). Our study highlights the various virulence-mechanisms employed by Mtb for infection and to overcome the hostile environment encountered during infection of NHP lungs. We would like to leverage our ability to model the various clinical phases of human TB - acute, pulmonary TB, chronic-progressive TB and latent, asymptomatic TB in NHPs - to study the growth/survival phenotype profiles of Mtb mutants. Further, we would like to better understand the role of two Mtb pathways crucial for virulence and pathogenesis, using the NHP model. These include the mce1/mce4 operons, whose members were among mutants that were attenuated for growth in NHP lungs; and members of the dos regulon, which were surprisingly not attenuated in NHP lungs, in-spite of their well-defined roles in latency, persistence and defense against hypoxia.