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，每年导致200万人死亡，并潜伏着感染世界三分之一的人口。作为一种适应长期生存的细胞内病原体，结核分枝杆菌已经进化出抵抗宿主抗菌途径杀伤的机制。针对这些耐药机制最近出现了一种有效的新方法，通过增强宿主根除细菌的能力来治疗结核分枝杆菌感染。然而，分枝杆菌耐药基因的完整谱系尚不清楚，扩大这一知识库为新药的开发提供了额外的途径。我们证明了结核分枝杆菌诱导一种酶，即血红素加氧酶，产生一氧化碳(CO)气体，结核分枝杆菌既能适应一氧化碳，又能抵抗一氧化碳的致死。我们假设结核分枝杆菌进化了CO抗性基因，我们的初步数据表明，结核分枝杆菌编码一个这样的基因，当突变时，导致毒力减弱。我们将应用代谢学、转录学、蛋白质组学和生化方法来确定新发现的CO抗性蛋白的功能。因此，在本研究中，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伙伴及其在CO抗性中的作用，(3)鉴定CO抗性基因及其相互作用伙伴中突变体的致病效应。这项拟议的工作将扩展目前关于结核分枝杆菌抗菌素耐药机制的知识，并揭示一种新的微生物生存策略。

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.