Toxin-antitoxins & RpsA in TB drug resistance & persistence with HIV

描述（申请人提供）：日益严重的耐多药/广泛耐药结核病问题对结核病控制构成了重大威胁，艾滋病毒感染有可能进一步加剧这一问题。分枝杆菌的持久性是长期治疗的基础，并且由于对长期治疗的依从性差，经常是耐药性的根本原因，因此，基于耐药性和持久性的新机制开发新药具有重大意义。WhiB 7是一种转录因子，其控制包括tap（Rv 1258 c）在内的8个基因的区域，编码四环素和氨基糖苷类排泄的外排蛋白，并且在内源性 抗生素耐药性和可能的耐受性或持久性。经治疗的慢性细菌或真菌感染具有增加的抗生素耐受性的变体，其与持久性相关的毒素-抗毒素（TA）基因多态性相关。临床分离的M.结核病携带whiB 7、tap和TA基因突变，但这些突变在药物耐受性/持久性中的作用尚不清楚。此外，最近发现了一种新的吡嗪酰胺（PZA）耐药机制，该机制是由于参与反式翻译的药物靶点RpsA突变引起的，但rpsA突变在导致PZA耐药中的作用尚不清楚。虽然耐多药结核病中的PZA耐药性与不良治疗结果相关，在世界某些地区范围为20-80%，但俄罗斯耐多药结核菌株中PZA耐药性的频率尚不清楚。因此，该项目将首先分析M的耐药临床分离株。在俄罗斯收集的耐多药结核病菌株中检测whiB 7、tap、TA模块和RpsA的多态性，并确定俄罗斯耐多药结核病菌株中PZA耐药的频率。第二，whiB 7，tap，TA模块和rpsA中的突变在耐药性和对抗生素和应激的持久性/耐受性以及巨噬细胞存活中的作用将得到解决。拟议的研究将填补在耐药性和持久性在M的知识的关键差距。TB.本研究的结果有助于了解耐药和持久性的机制，为设计持久性药物，缩短结核病的治疗时间，改善耐药结核病的治疗提供有用的信息。

DESCRIPTION (provided by applicant): The increasing MDR/XDR-TB problem poses a major threat to TB control, and HIV infection threatens to further aggravates the problem. Mycobacterial persistence underlies lengthy therapy and is often the root cause for drug resistance due to poor compliance to lengthy therapy, thus there is significant interest to develop novel drugs based on new mechanisms of drug resistance and persistence. WhiB7 is a transcription factor, which controls a region of 8 genes including tap (Rv1258c), encoding an efflux protein for tetracycline and aminoglycoside excretion, and plays a key role in the intrinsic antibiotic resistance and possibly tolerance or persistence. Treated chronic bacterial or fungal infections harbor variants with increased antibiotic tolerance associated with polymorphisms in toxin-antitoxin (TA) genes involved in persistence. Clinical isolates of M. tb harbor mutations in whiB7, tap and TA genes, but the role of these mutations in drug tolerance/persistence is unknown. Furthermore, a new mechanism of pyrazinamide (PZA) resistance due to mutations in drug target RpsA involved in trans-translation was recently identified, but the role of rpsA mutations in contributing to PZA resistance is unclear. While PZA resistance in MDR-TB, which is correlated with poor treatment outcome, ranges from 20-80% in some parts of the world, the frequency of PZA resistance in Russian MDR-TB strains is unknown. Therefore, the project will first analyze drug resistant clinical isolates of M. tb in Russian collection for polymorphisms in whiB7, tap, TA modules and RpsA and determine the frequency of PZA resistance in Russian MDR-TB strains. Second, the role of mutations in whiB7, tap, TA modules and rpsA in drug resistance and persistence/tolerance to antibiotics and stresses and survival in macrophages will be addressed. The proposed studies will fill in critical gaps in knowledge of drug resistance and persistence in M. tb. The outcome of this study will help to understand the mechanisms of drug resistance and persistence and provide useful information for design of persister drugs for shortening the TB treatment and improved treatment of drug-resistant TB.