Transcriptional response of M. tuberculosis to quinazoline-11626252 treatment. Transcriptional response of M. tuberculosis to quinazoline-11626252 treatment

We report here lead optimisation efforts of a new series of cytochrome bc1 oxidase inhibitors, the quinazoline derivatives. Four derivatives showed mild to no cytotoxicity as potent in vitro and ex vivo activity in infected THP-1 macrophages against M. tuberculosis. Isolation of resistant mutants to one of the derivatives in M. tuberculosis revealed mutations in both QcrA and QcrB of the cytochrome bc1 oxidase, one of two terminal oxidases of the mycobacterial electron transport chain. Cross-resistance studies, transcriptomic analyses and bioenergetics flux assays provide further evidence of the cytochrome bc1 as the target of the quinazolines compounds. The transcriptomic and bioenergetic profiles obtained when M. tuberculosis was treated with 11626252 are similar to transcriptomic and respiratory signatures of other cytochrome bc1 oxidase inhibitors. Overall design: To gain insight into the initial adaptive response of M. tuberculosis to quinazoline-11626252, the transcriptomes of wild-type H37Rv exposed to quinazoline-11626252 at 10x and 30x MIC for a duration of four hours were examined. Two biological replicates were used for each condition. The control samples (which were part of the same experiment) are available under accession GSM3111057 and GSM3111058.

本研究报道了一类新型细胞色素bc1氧化酶（cytochrome bc1 oxidase）抑制剂——喹唑啉（quinazoline）衍生物的先导优化工作。其中4种衍生物展现出轻度至无细胞毒性，同时对感染结核分枝杆菌（Mycobacterium tuberculosis，M. tuberculosis）的THP-1巨噬细胞具有强效的体外及离体抗结核活性。从结核分枝杆菌中分离得到针对该类衍生物之一的耐药突变株后发现，细胞色素bc1氧化酶的QcrA与QcrB基因发生突变，该酶是分枝杆菌电子传递链的两种末端氧化酶之一。交叉耐药性研究、转录组学分析及生物能通量检测进一步证实，细胞色素bc1氧化酶正是该喹唑啉类化合物的作用靶点。用化合物11626252处理结核分枝杆菌后得到的转录组与生物能特征谱，与其他细胞色素bc1氧化酶抑制剂的转录组及呼吸特征谱高度相似。
实验设计：为探究结核分枝杆菌对喹唑啉-11626252的初始适应性应答，本研究检测了以10倍最低抑菌浓度（minimum inhibitory concentration, MIC）及30倍MIC的喹唑啉-11626252处理野生型H37Rv菌株4小时后的转录组。每组设置2个生物学重复。本实验的对照样本登录号为GSM3111057与GSM3111058。