Lavin Richard C, Johnson Calvin, Ahn Yong-Mo, Kremiller Kyle M, Sherwood Matthew, Patel Jimmy S, Pan Yan, Russo Riccardo, MacGilvary Nathan J, Giacalone David, Kevorkian Yuzo L, Zimmerman Matthew D, Glickman J Fraser, Freundlich Joel S, Tan Shumin
Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America.
Graduate Program in Molecular Microbiology, Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America.
PLoS Biol. 2021 Jul 28;19(7):e3001355. doi: 10.1371/journal.pbio.3001355. eCollection 2021 Jul.
Sensing and response to environmental cues, such as pH and chloride (Cl-), is critical in enabling Mycobacterium tuberculosis (Mtb) colonization of its host. Utilizing a fluorescent reporter Mtb strain in a chemical screen, we have identified compounds that dysregulate Mtb response to high Cl- levels, with a subset of the hits also inhibiting Mtb growth in host macrophages. Structure-activity relationship studies on the hit compound "C6," or 2-(4-((2-(ethylthio)pyrimidin-5-yl)methyl)piperazin-1-yl)benzo[d]oxazole, demonstrated a correlation between compound perturbation of Mtb Cl- response and inhibition of bacterial growth in macrophages. C6 accumulated in both bacterial and host cells, and inhibited Mtb growth in cholesterol media, but not in rich media. Subsequent examination of the Cl- response of Mtb revealed an intriguing link with bacterial growth in cholesterol, with increased transcription of several Cl--responsive genes in the simultaneous presence of cholesterol and high external Cl- concentration, versus transcript levels observed during exposure to high external Cl- concentration alone. Strikingly, oral administration of C6 was able to inhibit Mtb growth in vivo in a C3HeB/FeJ murine infection model. Our work illustrates how Mtb response to environmental cues can intersect with its metabolism and be exploited in antitubercular drug discovery.
感知并响应环境线索，如pH值和氯离子（Cl-），对于结核分枝杆菌（Mtb）在其宿主中的定殖至关重要。利用荧光报告基因Mtb菌株进行化学筛选，我们鉴定出了一些化合物，这些化合物会破坏Mtb对高Cl-水平的反应，其中一部分命中化合物还能抑制Mtb在宿主巨噬细胞中的生长。对命中化合物“C6”，即2-(4-((2-(乙硫基)嘧啶-5-基)甲基)哌嗪-1-基)苯并[d]恶唑的构效关系研究表明，化合物对Mtb Cl-反应的干扰与对巨噬细胞中细菌生长的抑制之间存在相关性。C6在细菌和宿主细胞中均有积累，并在胆固醇培养基中抑制Mtb生长，但在丰富培养基中则无此作用。随后对Mtb的Cl-反应进行检查发现，其与在胆固醇中的细菌生长存在有趣的联系，即在同时存在胆固醇和高外部Cl-浓度的情况下，几个Cl-反应基因的转录增加，而与仅暴露于高外部Cl-浓度时观察到的转录水平相比。令人惊讶的是，在C3HeB/FeJ小鼠感染模型中，口服C6能够在体内抑制Mtb生长。我们的工作说明了Mtb对环境线索的反应如何与其代谢相互交叉，并可用于抗结核药物的发现。
