Discovery of marine natural products targeting latent M. tuberculosis

项目摘要 结核病是由结核分枝杆菌（Mtb）引起的毁灭性全球健康危机， 每年夺去200多万人的生命这种病原体能够在巨噬细胞内存活， 在患者体内存在多年，导致潜伏性结核感染（LTBI）。结核病对抗生素治疗是难治的 因为潜伏的（或休眠的）TB由于代谢和结构上的改变而表现出表型耐药性， 适应肺肉芽肿病变内的条件。因此，结核病的成功治疗 需要包括多种药物的混合物的方案，持续6-9个月。的出现 多重耐药结核分枝杆菌菌株使本已困难的结核病治疗任务进一步复杂化。因此，在本发明中， 迫切需要具有新的作用模式的强效药物， 治疗和杀灭耐药和潜伏的结核分枝杆菌。这项建议旨在解决这一严重缺乏 有效杀死潜伏结核病的药物。与港口海洋学研究所分支研究所合作， 我们将利用海洋次级代谢产物中存在的巨大化学多样性， 通过在两种模型中筛选海洋天然产物（MNP）的峰库来对抗Mtb， 延迟。在R21阶段，我们将在初步研究的基础上，筛选约5000个MNP的活性 在对数期肉汤培养物中对抗Mtb，在巨噬细胞中生长的Mtb，以及使用体外 潜伏期的多重应激模型（MSM）（目标1）。此外，我们将纯化和结构表征“命中” 我们在完成的中试筛选中鉴定了对Mtb具有杀菌作用的组分（Aim 2）。在R33阶段， 我们将从这三种化合物的命中馏分中纯化并确定优先活性化合物的结构。 筛选（目标3），最后，我们将对纯化的先导化合物进行详细表征， 确定其效力、特异性、潜在靶点和作用模式（目标4）。我们假设 这些模型将有助于识别针对靶向途径的潜伏性Mtb的药物 条件必需的生存在体内。我们预计MNP中存在的化学多样性将 有助于鉴定具有独特结构、靶点和作用机制的化合物。我们 长期目标是发现新的先导化合物，这将显着改善治疗 潜伏性和耐药性结核病。

Project Summary   Tuberculosis is a devastating global health crisis caused by Mycobacterium tuberculosis (Mtb) that claims over 2 million lives each year. This pathogen is able to survive inside macrophages and persist within patients for years, causing latent TB infections (LTBI). Mtb is refractory to antibiotic treatment because latent (or dormant) TB exhibit phenotypic drug resistance due to metabolic and structural adaptations to conditions within pulmonary granuloma lesions. As a result, successful treatment of TB requires a regimen including a cocktail of multiple drugs administered for 6-9 months. The emergence of multi-drug resistant Mtb strains has further complicated the already difficult task of treating TB. Thus, there is a dire need for potent drugs with novel modes of action capable of shortening the course of treatment and killing drug-resistant and latent Mtb. This proposal seeks to address this critical lack of drugs that effectively kill latent Mtb. In collaboration with Harbor Branch Oceanographic Institute (HBOI), we will exploit the enormous chemical diversity present among secondary metabolites of marine organisms by screening a peak library of marine natural products (MNP) against Mtb in two models of latency. In the R21 phase, we will build upon preliminary studies by screening ~5000 MNP for activity against Mtb in log-phase broth cultures, Mtb growing in macrophages, and dormant Mtb using an in vitro multi-stress model (MSM) of latency (Aim 1). In addition, we will purify and structurally characterize “hit” fractions bactericidal for Mtb which we identified in a completed pilot screen (Aim 2). In the R33 phase, we will purify and define the structures of prioritized active compounds from hit fractions from all three screens (Aim 3), Finally, we will conduct detailed characterization of purified lead compounds to determine their potency, specificity, and potential targets and mode of action (Aim 4). We hypothesize that these models will favor the identification of drugs active against latent Mtb that target pathways conditionally essential for survival in vivo. We anticipate that the chemical diversity present in MNP will facilitate the identification of compounds with unique structures, targets, and mechanisms of action. Our long-term goal is the discovery of novel lead compounds that would significantly improve the treatment of latent and drug-resistant tuberculosis.