Metabolomics approaches to TB drug development

描述（由申请人提供）：抗生素开发是未满足医疗需求的主要领域。没有任何地方比结核病（TB）更需要这种治疗，结核病是全世界主要的细菌性死亡原因。控制结核病大流行的一个主要障碍是缺乏对结核病病原体结核分枝杆菌（Mtb）的复制和非复制形式都有活性的药物。因此，了解针对复制型和非复制型结核病的新靶标是尚未满足的科学需求的主要领域。一种有效的，但研究不足的，对复制型和非复制型结核分枝杆菌都有活性的化合物是活性氮中间体（RNI）。在体外，RNI杀死Mtb的摩尔效力大于许多目前使用的TB药物。因此，RNI的抗分枝杆菌机制的知识代表了复制型和非复制型Mtb中潜在靶标的概念蓝图。在以前的工作中，我们确定了结核分枝杆菌中RNI介导的损伤的蛋白质组靶点。这项工作的动机是认为RNI介导的损伤的靶点代表了潜在的药物靶点，其抑制与RNI无关的化合物将模拟RNI的杀分枝杆菌活性并抵抗Mtb的RNI防御。令人惊讶的是，这项工作选择性地确定了Mtb中间代谢的酶作为主要类别的潜在药物靶标，而不是现有结核病药物的靶点。在这里，我们建议应用一种新的基于质谱的代谢组学工具，不仅有助于定义RNI对复制和非复制Mtb的抗分枝杆菌作用，而且更广泛地扩展了Mtb在代谢物的生化全球水平上的代谢网络的知识。为此，我们将使用各种设置之间和之间的RNI介导的对Mtb代谢组的杀伤的无偏比较来推断药物化合物的MOA或靶标（类似于基因组学中使用的已经证明的“纲要”方法）。作为概念验证，我们提出了初步数据，肯定了代谢物分析（使用结核分枝杆菌的游离氨基酸池）的概念价值，以及结核分枝杆菌的全球代谢物分析的技术可行性。我们特别寻求确定一个“通用”的RNI代谢组学签名，这将解释他们对复制和非复制结核分枝杆菌的精致的效力。这些知识将为研究新的药物靶点提供一个新的透镜，这些药物靶点可能会增强或协同天然免疫力。从更广泛的角度来看，这项工作不仅将促进在复制型和非复制型结核分枝杆菌中鉴定新的潜在药物靶标的努力，而且还为未来研究具有未定义MOA的抗分枝杆菌化合物奠定基础。公共卫生相关性：抗生素开发是未满足医疗需求的主要领域。没有任何地方比结核病（TB）更需要这种治疗，结核病是全世界主要的细菌性死亡原因。控制结核病大流行的一个主要障碍是缺乏对结核病病原体结核分枝杆菌（Mtb）的复制和非复制形式都有活性的药物。因此，对针对复制型和非复制型结核病的新靶标的了解解决了当前流行病的主要未满足的科学需求。

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.