Drugs targeting persistent Mycobacterium Tuberculosis

描述（由申请人提供）：结核病（TB）是一种毁灭性的细菌性疾病，原因有两个：首先是因为涉及的数量巨大，大约1/3的人类被感染，大约1500万人在任何时候都处于活动性疾病状态，每年约有200万人死于结核病。其次，结核病是最难治疗的细菌感染之一。完全治疗对药物敏感的活动性结核病病例需要6个月，并且需要4种不同的抗生素。耐多药结核病（MDR）和广泛耐药结核病（XDR）分别对部分或全部一线抗生素具有耐药性，并且需要对患者更危险的药物，通常必须静脉注射，而且价格要贵得多。目前迫切需要治疗结核病的作用更快、副作用更少的抗生素，以及对耐多药和广泛耐药结核病有效的抗生素。我们发现，在体外浮游生长过程中，不能形成生物膜的突变体对抗生素更敏感。受这些结果的启发，我们假设体外生物膜形成可能是一种独特的表型，用于开发具有新机制作用的抑制剂的高通量筛选。基于细胞筛选的70,000种化合物抑制耻垢分枝杆菌生物膜形成的分子产生了许多强烈抑制结核分枝杆菌（Mtb）生物膜形成的化合物。其中一种候选TCA1对药敏结核分枝杆菌和耐药结核分枝杆菌均有杀菌活性，可与利福平（RIF）或异烟肼（INH）协同体外灭菌结核分枝杆菌。此外，TCA1在体外对复制型和非复制型结核分枝杆菌均表现出杀灭活性。此外，我们已经证明TCA1在Mtb小鼠感染模型中具有活性，无论是独立的还是与INH或RIF联合的，这表明它是一个有希望的药物开发先导。我们建议对TCA1的生物学机制进行表征，并开展构效关系（SAR）研究，以提高该分子对易感和耐药结核分枝杆菌的效价和药代动力学。结果将是具有体内有效性证明的强有力的先导候选药物，可以通过未来资助的合作努力进一步优化和开发，作为治疗结核病的新疗法。

DESCRIPTION (provided by applicant): Tuberculosis (TB) is a devastating bacterial disease for two reasons: First because there are huge numbers involved, approximately 1/3 of humanity is infected, about fifteen million people are in active disease at any one time and about two million die of TB each year. Secondly, TB is one of the most difficult bacterial infections to trea. To treat fully drug-sensitive cases of active TB takes six months and requires four different antibiotics. Multi-Drug Resistant (MDR) and eXtensively Drug Resistant (XDR) TB are resistant to some, or all, respectively, of the first line antibiotics and require drugs that are more dangerous to the patient, often must be given intravenously, and are much more expensive. There is an urgent need for faster-acting antibiotics against TB with fewer side effects and for antibiotics that are effective against MDR and XDR TB. We found that mutants unable to make biofilms are more sensitive to antibiotic in vitro during planktonic growth. Inspired by these results, we hypothesized that in vitro biofilm formation could be a unique phenotype to develop a high-throughput screen for inhibitors with novel mechanism(s) of action. A cell-based screen of 70,000 compounds for molecules that inhibit biofilm formation in Mycobacterium smegmatis yielded a number of compounds that strongly inhibit biofilm formation in Mycobacterium tuberculosis (Mtb). One candidate TCA1 has bactericidal activity against both drug susceptible and drug resistant Mtb and synergizes with rifampcin (RIF) or isoniazid (INH) in sterilization of Mtb in vitro. In addition TCA1 showed bactericidal activity against both replicating and non-replicating Mtb in vitro. Furthermore, we have demonstrated that TCA1 is active in a Mtb mouse infection model both independently and in conjunction with INH or RIF suggesting that it is a promising lead for drug development. We propose to characterize the biological mechanism of TCA1 and carry out structure-activity relationship (SAR) studies to improve the potency and pharmacokinetics of this molecule against susceptible and drug resistant Mtb. The result will be robust lead candidates with in vivo proof of efficacy that can be further optimized and developed through future funded collaborative efforts as novel therapeutics for the treatment of TB.