Drug-resistant Mycobacterium tuberculosis (Mtb) remains a major public health concern requiring complementary approaches to standard anti-tuberculous regimens. Anti-virulence molecules or compounds that enhance the activity of antimicrobial prodrugs are promising alternatives to conventional antibiotics. Exploiting host cell-based drug discovery, we identified an oxadiazole compound (S3) that blocks the ESX-1 secretion system, a major virulence factor of Mtb. S3-treated mycobacteria showed impaired intracellular growth and a reduced ability to lyse macrophages. RNA sequencing experiments of drug-exposed bacteria revealed strong upregulation of a distinct set of genes including ethA, encoding a monooxygenase activating the anti-tuberculous prodrug ethionamide. Accordingly, we found a strong ethionamide boosting effect in S3-treated Mtb. Extensive structure-activity relationship experiments revealed that anti-virulence and ethionamide-boosting activity can be uncoupled by chemical modification of the primary hit molecule. To conclude, this series of dual-active oxadiazole compounds targets Mtb via two distinct mechanisms of action.

耐药结核分枝杆菌( Mtb ) 仍然是一个主要的公共卫生问题，需要标准抗结核治疗方案的补充方法。增强抗菌前药活性的抗毒力分子或化合物是传统抗生素的有前途的替代品。利用基于宿主细胞的药物发现，我们发现了一种恶二唑化合物 (S3)，它可以阻断 ESX-1 分泌系统（ Mtb的主要毒力因子） 。 S3 处理的分枝杆菌表现出细胞内生长受损和裂解巨噬细胞的能力降低。对接触药物的细菌进行的 RNA 测序实验显示，一组独特的基因出现强烈上调，其中包括ethA ，编码激活抗结核前药乙硫异烟胺的单加氧酶。因此，我们发现乙硫异烟胺对 S3 处理的结核分枝杆菌有很强的增强作用。广泛的结构-活性关系实验表明，抗毒力和乙硫异烟胺增强活性可以通过主要命中分子的化学修饰来解偶联。总之，这一系列双活性恶二唑化合物通过两种不同的作用机制靶向Mtb 。