Metabolomics approaches to TB drug development

描述(由申请人提供)：抗生素开发是未得到满足的医疗需求的一个主要领域。没有哪个地方比结核病(TB)更需要这种需求，结核病是导致全球死亡的主要细菌原因。控制结核病大流行的一个主要障碍是缺乏对其病原体结核分枝杆菌(结核分枝杆菌)的复制型和非复制型有效的药物。因此，针对复制型和非复制型结核分枝杆菌的新靶点的知识是尚未满足的科学需求的一个主要领域。活性氮中间体(RNI)是一类对复制和非复制结核分枝杆菌都有活性的化合物，但研究较少。在体外，RNI以比目前使用的许多结核病药物更大的摩尔效力杀死结核分枝杆菌。因此，对RNI抗分枝杆菌机制的了解(S)代表了复制和非复制结核分枝杆菌潜在靶点的概念蓝图。在以前的工作中，我们确定了RNI介导的Mtb损伤的蛋白质组学靶点。这项工作的动机是这样一种观点，即RNI介导的损伤靶点代表着潜在的药物靶点，其被与RNI无关的化合物抑制将模仿RNI的杀分支杆菌活性并抵抗Mtb的RNI防御。令人惊讶的是，这项工作选择性地将结核分枝杆菌中间代谢的酶确定为一类主要的潜在药物靶点，而不是现有结核病药物的靶标。在这里，我们建议应用一种新的基于质谱学的代谢组学工具，它不仅将有助于定义RNI对复制和非复制结核分枝杆菌的抗分枝杆菌作用，而且更广泛地在生化全球代谢物水平上扩展对结核分枝杆菌代谢网络的了解。为此，我们将使用无偏倚的RNI介导的对Mtb代谢组的杀伤跨各种设置和在各种设置之间的比较来推断MOA或药理化合物的靶标(类似于已经被证明是基因组学中使用的“概要”方法)。作为概念验证，我们提供的初步数据肯定了代谢物图谱的概念价值(使用MTB的游离氨基酸库)以及MTB全球代谢物图谱的技术可行性。我们特别寻求确定RNI的“通用”代谢特征，以解释它们对抗复制和非复制结核分枝杆菌的卓越效力。这些知识将为新的药物靶点提供一个新的视角，这些靶点可能会增强或协同自然免疫。从更广泛的角度来看，这项工作不仅将推动在复制和非复制Mtb中寻找新的潜在药物靶点的努力，而且还将为未来MOA未定义的抗分枝杆菌化合物的研究奠定基础。公共卫生相关性：抗生素开发是未得到满足的医疗需求的一个主要领域。没有哪个地方比结核病(TB)更需要这种需求，结核病是导致全球死亡的主要细菌原因。控制结核病大流行的一个主要障碍是缺乏针对复制型和非复制型结核分枝杆菌(结核分枝杆菌)的有效药物，结核分枝杆菌是结核病的病原体。因此，对针对复制型和非复制型结核分枝杆菌的新靶点的了解解决了当前大流行尚未得到满足的重大科学需求。

DESCRIPTION (provided by applicant): Antibiotic development is a major area of unmet medical need. Nowhere is this need greater than in the case of tuberculosis (TB), the leading bacterial cause of deaths worldwide. A major roadblock to control of the TB pandemic is the lack of drugs active against both replicating and non-replicating forms of its causative agent, Mycobacterium tuberculosis (Mtb). Knowledge of new targets against both replicating and non-replicating Mtb is thus a major area of unmet scientific need. One potent, but understudied, class of compounds active against both replicating and non-replicating Mtb is the reactive nitrogen intermediates (RNI). In vitro, RNI kill Mtb with a molar potency greater than that of many currently used TB drugs. Knowledge of the antimycobacterial mechanism(s) of RNI thus represents a conceptual blueprint to potential targets in replicating and non-replicating Mtb alike. In previous work, we identified proteomic targets of RNI-mediated damage in Mtb. This work was motivated by the view that targets of RNI-mediated damage represented potential drug targets whose inhibition by compounds unrelated to RNI would mimic RNI's mycobactericidal activity and resist Mtb's RNI defenses. Surprisingly, this work selectively identified enzymes of Mtb's intermediary metabolism as a major class of potential drug targets, not targeted by existing TB drugs. Here, we propose to apply a novel mass spectrometry-based metabolomics tool that will not only help define the antimycobacterial actions of RNI against both replicating and non-replicating Mtb but more broadly expand knowledge of Mtb's metabolic network at the biochemically global level of metabolites. To do so, we will deduce the MOA or targets of pharmacologic compounds using unbiased, comparisons of RNI-mediated killing on the Mtb metabolome across and between a variety of settings (analogous to the already proven "compendium" approach used in genomics). As proof-of-concept validation, we present Preliminary Data that affirm the conceptual merit of metabolite profiling (using Mtb's free amino acid pools) as well as the technical feasibility of global metabolite profiling of Mtb. We specifically seek to identify a "universal" metabolomic signature of RNI that would explain their exquisite potency against replicating and non-replicating Mtb alike. Such knowledge would provide a fresh lens on new drug targets that might augment or synergize with natural immunity. From a broader point of view, this work will not only advance efforts to identify new potential drug targets in replicating and non- replicating Mtb but also lay the groundwork for future studies of antimycobacterial compounds with undefined MOA. PUBLIC HEALTH RELEVANCE: Antibiotic development is a major area of unmet medical need. Nowhere is this need greater than in the case of tuberculosis (TB), the leading bacterial cause of deaths worldwide. A major roadblock to control of the TB pandemic is the lack of drugs active against both replicating and non-replicating forms Mycobacterium tuberculosis (Mtb), the causative agent of TB. Knowledge of new targets against both replicating and non-replicating Mtb thus addresses a major unmet scientific need of the current pandemic.