A "radical" approach to tuberculosis infection

描述（由申请人提供）：结核病仍然是一种发病率和死亡率很高的疾病。使其管理复杂化的是其多种表现，从急性疾病到潜伏感染。据估计，世界人口的1/3患有晚期结核病，这导致了一个巨大的库，可以发生急性疾病的重新激活。迫切需要更有效的药物来简化和缩短疗程，以应对遵守绝育和治愈所需的漫长疗程的挑战。 在活动性和潜伏性感染期间，已经提出细菌的群体或亚群进入可逆的非复制状态，传统抗生素难以治疗。术语表型抗生素耐受性（药物耐受性）用于描述在不存在基因型耐药性的情况下抗生素对这些细菌的效力降低。在结核分枝杆菌中，有人提出体内药物耐受性可以解释长期治疗后感染的持续性。因此，将我们对药物耐受性的理解和面对化疗时细菌存活的基础整合到治疗发现中可能是设计针对潜伏和持续感染的新策略的关键。 近年来，抗生素诱导的活性氧（ROS）已被认为在敏感细胞中的抗生素疗效中发挥重要作用，而对抗ROS的保护机制在药物耐受性中发挥作用。事实上，这种保护机制已经涉及到所有目前的体外药物耐受性模型。因此，抑制或压倒允许耐药细菌在ROS的细胞应激中存活的机制是快速杀灭潜伏或持续感染的创新的、有前途的策略。在该项目中，我们提出开发新的assas以鉴定能够通过破坏耐药Mtb杆菌的解毒能力而杀灭耐药Mtb杆菌并因此在ROS的应激中存活的小分子候选物，或增加细菌中ROS的产生从而导致其死亡。我们将使用一种药物耐受模型，利用硫脲淬灭抗生素暴露产生的羟基自由基的能力，从而诱导药物耐受。然后，我们将筛选两个独特的，有价值的小分子集合：我们已经确定的676种分子的集合，这些分子对营养缺乏的结核分枝杆菌具有活性，这些分子对目前可用的结核药物具有耐药性，以及在布罗德研究所创建的独特的100，000多样性导向的合成分子库。将开发有希望的候选物，以获得用于在慢性和潜伏性结核病小鼠模型中进行测试的分子。这项工作将整合新的生物学概念，靶向ROS介导的机制，靶向持久性和潜伏期与新的化学在DOS图书馆收藏，并将借鉴药物发现的专业知识，从制药行业的领导人现在在布罗德研究所和专业知识在体内测试结核病候选药物在约翰霍普金斯。

DESCRIPTION (provided by applicant): Tuberculosis continues to be a disease of significant morbidity and mortality. Complicating its management are its diverse manifestations, ranging from acute disease to latent infection. It is estimated that 1/3 of the world's population has latet TB, resulting in an enormous reservoir from which reactivation to acute disease can occur. More effective drugs are urgently needed to simplify and shorten treatment courses in order to address the challenges of compliance to the requisite lengthy courses required for sterilization and cure. During both active and latent infection, it has been proposed that a population or subpopulation of bacteria enters a reversible non-replicating state, refractory to traditional antibiotics. The term phenotypic antibiotic tolerance (drug tolerance) is used to describe the reduced efficacy of antibiotics against these bacteria in the absence of genotypic resistance. In Mtb, it has been proposed that in vivo drug tolerance could explain the persistence of infection in the face of prolonged therapy. Thus, integrating our understanding of drug tolerance and the basis for bacterial survival in the face of chemotherapy into therapeutic discovery could be key to designing new strategies for targeting latent and persistent infection. Recently, antibiotic-induced reactive oxygen species (ROS) have been recognized as playing an important role in antibiotic efficacy in susceptible cells while mechanisms that protect against ROS play a role in drug tolerance. In fact, such protective mechanisms have been implicated in all current in vitro models of drug tolerance. Thus, inhibiting or overwhelming the mechanisms that allow drug-tolerant bacteria to survive the cellular stress of ROS is an innovative, promising strategy to rapidly sterilize latent or persistent infection In this project, we propose to develop novel assas to identify small molecule candidates which are able to sterilize drug tolerant Mtb bacilli by disrupting their ability to detoxify and thus survive the stress of ROS, or that increase ROS production in bacilli thus contributing to their death. We will use a model of drug tolerance that exploits the ability of thiourea to quench hydroxyl radicals generated by antibiotic exposure, thereby inducing drug tolerance. We will then screen two unique, valuable collections of small molecules: a collection of 676 molecules that we have already identified as having activity against nutrient starved Mtb which are otherwise drug tolerant to currently available TB drugs, and a unique 100,000 diversity oriented synthetic molecule library that has been created at the Broad Institute. Promising candidates will be developed to obtain molecules for testing in chronic and latent mouse models of TB. This work will integrate the novel biological concept of targeting ROS-mediated mechanisms for targeting persistence and latency with novel chemistry in the DOS library collection, and will draw upon drug discovery expertise from leaders in the pharmaceutical industry now at the Broad Institute and expertise in in vivo testing of TB drug candidates at Johns Hopkins.