Carbon monoxide resistance in Mycobacterium tuberculosis pathogenesis

描述（申请人提供）：结核分枝杆菌仍然是最具破坏性的人类传染病之一，每年造成200万人死亡，并潜伏感染世界三分之一的人口。作为一种适应长期生存的胞内病原菌，M.结核病已经进化出抵抗宿主抗微生物途径杀死的机制。针对这些耐药机制最近已成为治疗M的一种强有力的新方法。通过增强宿主消灭细菌的能力来预防结核病感染。然而，分枝杆菌耐药基因的完整库尚不清楚，扩大这一知识基础为新药的开发提供了额外的途径。我们展示了M。结核病诱导一种酶，血红素加氧酶，产生一氧化碳（CO）气体，并且M.结核杆菌既适应又抵抗CO的杀伤。结核分枝杆菌进化出了抗CO的基因，我们的初步数据表明，M.结核病编码一种这样的基因，当突变时导致毒力减弱。我们将应用代谢组学、转录组学、蛋白质组学和生物化学方法来确定新发现的抗CO蛋白的功能。因此，在拟议的研究中，我们将（1）确定CO抗性的分子机制，（2）确定CO抗性基因的相互作用伴侣及其在CO抗性中的作用，（3）表征CO抗性基因及其相互作用伴侣突变体的致病作用。本文的工作将扩展现有的关于M.结核病的耐药性机制，并揭示了一种新的微生物生存策略。公共卫生相关性：结核病是一种主要的人类病原体，在全世界范围内造成严重的发病率和死亡率。在这项提案中概述的工作将调查一种新的机制，使M。结核病在人体内存活和持续存在。我们希望这项工作将有助于确定治疗结核病的新的潜在药物靶点。 公共卫生相关性：结核分枝杆菌在宿主体内生存的机制尚不完全清楚。我们建议研究M.肺结核在暴露于一氧化碳（一种由宿主巨噬细胞产生的有毒气体）下存活，重点是我们在一氧化碳抗性突变体筛选中鉴定的分枝杆菌基因Rv1829。这种方法是新颖的，因为它代表了在一个主要的人类病原体中的CO抗性基因的第一个描述。

DESCRIPTION (provided by applicant): Mycobacterium tuberculosis remains one of the most devastating human infectious diseases, causing two million deaths annually and latently infecting a third of the world's population. As an intracellular pathogen adapted to long-term survival, M. tuberculosis has evolved mechanisms to resist killing by host antimicrobial pathways. Targeting those resistance mechanisms has recently emerged as a powerful new approach to treating M. tuberculosis infection by enhancing the host's ability to eradicate the bacteria. However, the full repertoire of mycobacterial resistance genes is not known, and expanding this knowledge base provides additional avenues for the development of new drugs. We demonstrated the M. tuberculosis induces an enzyme, heme oxygenase, that produces carbon monoxide (CO) gas, and that M. tuberculosis both adapts to and resists killing by CO. We hypothesized that M. tuberculosis evolved genes for CO resistance, and our preliminary data indicate that M. tuberculosis encodes one such gene that when mutated results in attenuated virulence. We will apply metabolomic, transcriptomic, proteomic, and biochemical approaches to determine the function of the newly discovered CO resistance protein. Thus, in the proposed research we will (1) identify the molecular mechanism of CO resistance, (2) determine the interacting partners of the CO resistance gene and their role in CO resistance and (3) characterize the pathogenic effects of mutants in the CO resistance gene and its interacting partners. The proposed work will extend the current knowledge on M. tuberculosis's antimicrobial resistance mechanisms and reveal a novel microbial survival strategy. PUBLIC HEALTH RELEVANCE: Tuberculosis is a major human pathogen, accounting for significant morbidity and mortality worldwide. Work outlined in this proposal will investigate a novel mechanism that allows M. tuberculosis to survive and persist within humans. We expect that this work will help identify new potential drug targets for the treatment of tuberculosis. PUBLIC HEALTH RELEVANCE: The mechanisms used by Mycobacterium tuberculosis to survive within the host are incompletely understood. We propose to study how M. tuberculosis survives exposure to carbon monoxide, a toxic gas produced by host macrophages, focusing on the mycobacterial gene Rv1829 that we identified in a screen for CO resistance mutants. This approach is novel because it represents the first description of a CO resistance gene in a major human pathogen.