结核分枝杆菌利福平耐药性和错误翻译研究

Tuberculosis, caused by Mycobacterium tuberculosis is one of the most important infectious diseases. Current treatment regimens are inadequate, requiring months to years of antibiotic therapy. These long treatment times are largely due to population(s) of bacteria that are not killed effectively by antibiotics, despite being genetically susceptible to the drugs. The molecular mechanisms that cause this mycobacterial antibiotic tolerance are not well understood. We have recently described one mechanism by which mycobacteria become tolerant to the first-line antibiotic, rifampicin, through increased errors in specific codons during gene translation, mistranslation. Through a forward genetic screen, we have now identified a component of the mycobacterial translation pathway, the enzyme complex GatCAB, which is critical for mistranslation that results in increased rifampicin tolerance. We will investigate the contribution of mutations in M. tuberculosis gatA to adaptive mistranslation and rifampicin tolerance both in vitro and in vivo and determine the contribution of variation in GatCAB in clinical isolates of M. tuberculosis. At the conclusion of this study, we will understand the function of mycobacterial GatCAB, and its role in mistranslation and antibiotic tolerance both within lab and clinical strains of M. tuberculosis. This will in turn help in the development of specific therapies that will shorten tuberculosis therapy duration.

结核病是由结核分枝杆菌所致的一类重要的传染性疾病，结核分枝杆菌的表观耐药性是结核病治疗周期长和易复发的主要原因之一。本课题组近年来的研究发现分枝杆菌可以通过特定的蛋白质错误翻译（mistranslation）获得对一线抗结核药物利福平的表观耐药性，同时发现了GatCAB复合体在该通路中具有潜在的作用。本项目将在上述工作的基础上，通过体外实验与小鼠在体实验以研究gatA基因及其突变体在结核分枝杆菌适应性错误翻译及利福平表观耐药性中的作用。同时，我们还将探究从结核分枝杆菌临床分离株中鉴定到GatCAB变异对于这些临床分离株表观耐药程度的贡献。通过上述基础及临床研究我们将对结核分枝杆菌GatCAB复合体的功能以及它在蛋白质错误翻译和利福平表观耐药性中的作用有更明确的了解，同时也将有助于发展新的治疗方案以缩短结核病的治疗周期。

结核病是由结核分枝杆菌所致的一类重要的传染性疾病，结核分枝杆菌的表观耐药是结核病治疗周期长且易复发的主要原因之一。本课题组以往研究发现结核分枝杆菌可通过特定的蛋白质错误翻译获得对一线抗结核药物利福平的表观耐药性，同时发现了GatCAB复合体在此通路中的潜在作用。本项目旨在通过体外实验与小鼠在体实验研究gaA基因及其突变体在结核分枝杆菌适应性错误及利福平表观耐药性中的作用，同时探索从结核分枝杆菌临床分离株中鉴定到的GatCAB突变对于这些临床分离株的表观耐药程度的贡献。基于以上的基础和临床研究来进一步了解GatACB复合体的功能以及它在蛋白质错误翻译和利福平表观耐药性中的作用。通过采用一系列分子生物学、遗传学和动物实验等手段，本课题组首次揭示结核分枝杆菌耐药性的分子机制可能是由于gatA的突变，导致了利福平耐药的分子机制，解释了利福平的剂量和gatCAB介导的错误翻译具有协同效应并利用小分子药物抑制错误翻译通路则会降低利福平的耐药性。在此过程中，也开发出了一些用于测量分枝杆菌的错误翻译和蛋白质错误折叠的技术手段。这些研究成果从一个新的角度解释了结核病耐药性产生的原因——蛋白质的错误翻译，为缩短结核病治疗周期的提供了新的思路。