Inhibition of methionine biosynthesis eliminates persistent M. tuberculosis.

 描述(申请人提供)：结核分枝杆菌是世界上最致命的细菌病原体，每年导致120万人死亡，感染人数超过800万(世卫组织，2013年)。尽管存在针对结核病的化疗，但全球多药耐药(MDR)和广泛耐药(XDR)结核病病例的迅速增加使得具有新的杀伤机制的新药成为迫切需要。目前结核病化疗的一个主要缺点是持续时间长，这增加了复发的可能性和出现耐药性。这一现象的根本问题是非复制型、耐药杆菌的种群，即所谓的持久者。然而，目前的结核病药物主要是对复制和代谢活性细菌有效。新药最好能迅速杀死(在几周内)，并针对活跃生长和持久生长的细胞。利用多学科方法，我们已经确定了结核分枝杆菌蛋氨酸生物合成的一个新的药物靶点。我们的初步结果非常有希望，因为它们显示了结核分枝杆菌蛋氨酸缺乏症的快速体外灭菌，以及免疫活性和免疫受损的小鼠完全缺乏毒力。这很耐人寻味，因为大多数现有的结核病抗生素并不能迅速消毒培养物。代谢组学和转录组分析揭示了一种前所未有的多靶点抑制机制导致的系统性代谢停滞。通过引起快速的生物合成和代谢发作来杀死结核分枝杆菌的前景在药物开发中非常有吸引力。该方案的目的是在体外和体内验证该药物靶点，并开发一种用于全细胞抑制剂筛选的报告菌株。这将为在不久的将来针对这一目标进行全面的高通量抑制物筛选奠定基础。

 DESCRIPTION (provided by applicant): Mycobacterium tuberculosis is the most deadly bacterial pathogen in the world, killing 1.2 million people yearly and infecting over 8 million (WHO, 2013). Although chemotherapy against TB exists, a rapid global increase of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) cases makes new drugs with novel killing mechanisms an urgent need. A major drawback of current TB chemotherapy is its long duration, which increases the probability of relapse and the emergence of drug resistance. The underlying problem of this phenomenon is a population of non-replicating, drug-tolerant bacilli, the so-called persisters. However, current TB drugs are mainly effective against replicating and metabolically active bacteria. Preferably, new drugs kill fast (within weeks) and target actively growing as well as persister cells. Using a multidisciplinary approach, we have identified a novel drug target in methionine biosynthesis of M. tuberculosis. Our preliminary results are very promising, as they show rapid in vitro sterilization of a M. tuberculosis methionine auxotroph as well as complete lack of virulence in immunocompetent and immunocompromised mice. This is intriguing because most available TB antibiotics do not rapidly sterilize cultures. Metabolomics and transcriptomic analysis revealed a systemic metabolic shutdown by an unprecedented multi-target inhibition mechanism. The prospect of killing M. tuberculosis by causing rapid biosynthetic and metabolic seizure is very attractive for drug discovery. The goal of this proposal is to validate this drug target in vitro and in vivo and o develop a reporter strain for whole cell inhibitor screening. This will set the stage for a comprehensive high-throughput inhibitor screen against this target in the near future.