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。其表现多样，从急性疾病到潜伏感染，使其管理复杂化。据估计，世界上有三分之一的人口患有晚期结核病，这造成了一个巨大的病毒库，可由此重新激活为急性疾病。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必要漫长疗程的挑战。在活动性和潜伏性感染期间，已经提出细菌种群或亚种群进入可逆的非复制状态，对传统抗生素无效。表型抗生素耐受性（药物耐受性）一词用于描述在没有基因型耐药的情况下抗生素对这些细菌的疗效降低。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时感染的持续存在。因此，将我们对药物耐受性的理解和面对化疗时细菌生存的基础整合到治疗发现中可能是设计针对潜伏性和持续性感染的新策略的关键。近年来，抗生素诱导的活性氧（ROS）在敏感细胞的抗生素疗效中起着重要作用，而对ROS的保护机制在药物耐受性中起着重要作用。事实上，这种保护机制已经涉及到目前所有的体外药物耐受模型。因此，抑制或压制允许耐药细菌在ROS细胞应激下存活的机制是一种创新的、有前途的策略，可以快速杀灭潜伏或持续感染。在本项目中，我们建议开发新的assas来鉴定能够通过破坏耐药结核杆菌的解毒能力来杀灭耐药结核杆菌的小分子候选物，从而在ROS的应激下存活下来。或者增加细菌中活性氧的产生从而导致其死亡。我们将使用一种药物耐受性模型，利用硫脲的能力来抑制抗生素暴露产生的羟基自由基，从而诱导药物耐受性。然后，我们将筛选两个独特的、有价值的小分子集合：一个是我们已经确定的676个分子的集合，这些分子对营养匮乏的结核分枝杆菌具有活性，否则对现有的结核病药物具有耐药性；另一个是Broad研究所创建的独特的100,000个面向多样性的合成分子库。将开发有希望的候选药物，以获得用于慢性和潜伏性结核小鼠模型的分子。这项工作将整合新的生物学概念，即靶向ros介导的靶向持久性和潜伏期的机制，以及DOS库中的新化学，并将利用Broad研究所制药行业领导者的药物发现专业知识和约翰霍普金斯大学结核病候选药物体内测试的专业知识。

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.