Discovery of marine natural products targeting latent M. tuberculosis

描述(申请人提供)：结核病是一种由结核分枝杆菌(Mtb)引起的毁灭性的全球健康危机，每年夺走200多万人的生命。这种病原体能够在巨噬细胞内存活，并在患者体内持续多年，导致潜在的结核病感染(LTBI)。结核分枝杆菌对抗生素治疗不耐药，因为潜伏期(或潜伏期)结核表现出表型耐药性，这是由于代谢和结构对肺肉芽肿病变内的条件的适应。因此，成功的结核病治疗需要一种方案，包括6-9个月的多种药物的鸡尾酒疗法。耐多药结核分枝杆菌菌株的出现使本已困难的结核病治疗任务进一步复杂化。因此，迫切需要有效的药物，具有新的作用模式，能够缩短疗程，杀死耐药和潜伏的结核分枝杆菌。这项提案旨在解决这一严重缺乏有效杀死潜伏的结核分枝杆菌的药物的问题。我们将与海港分会海洋研究所(HBOI)合作，通过在两种潜伏期模型中筛选抗结核杆菌的海洋天然产物(MNP)峰值文库，来开发海洋生物次生代谢物中存在的巨大化学多样性。在R21阶段，我们将在初步研究的基础上，利用潜伏期的体外多应激模型(MSM)，在对数期肉汤培养、巨噬细胞中生长的Mtb和休眠Mtb中筛选~5000 MNP的抗Mtb活性(目标1)。此外，我们将提纯和结构表征我们在一个完整的中试筛选(目标2)中确定的对结核分枝杆菌具有杀菌作用的“命中”部分。在R33阶段，我们将从所有三个筛选的命中部分提纯并确定优先活性化合物的结构(目标3)，最后，我们将对纯化的先导化合物进行详细的表征，以确定它们的效力、特异性和潜在的靶标和作用模式(目标4)。我们假设，这些模型将有利于识别抗潜伏性结核分枝杆菌活性的药物，这些药物针对的是对体内生存至关重要的有条件的通路。我们预计，MNP中存在的化学多样性将有助于识别具有独特结构、靶点和作用机制的化合物。我们的长期目标是发现新的先导化合物，从而显著改善潜伏性和抗药性结核病的治疗。

DESCRIPTION (provided by applicant): 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, ther 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 whic 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.