Repurposing antimalarials for the treatment of NTM infections

摘要 分枝杆菌所致肺部非结核分枝杆菌感染的流行情况 脓肿复合体(MABSC)和禽分枝杆菌复合体(MAC)种类在全球范围内不断增加， 对患有结构性或功能性肺部疾病(如囊性肺炎)的易感人群构成特别威胁 纤维化、慢性阻塞性肺疾病和支气管扩张。这些人的内在顽固性 病原体到化疗和令人震惊的治疗失败率将高度优先放在 开发更有效的治疗方法。 MABSC和MAC在肉芽肿性病变细胞内和细胞外持续存在的能力 非复制状态可能导致这些微生物的药物耐受性和治疗失败。 在慢性感染者身上。进一步加剧这个问题的是MABSC和MAC形成的能力 这似乎是人类肺部感染过程中的基因编程生物膜。面临的共同压力 通过活化的免疫细胞内和细胞外的NTM，在无血管坏死区和干酪区 肉芽肿，在微团聚体或生物膜内是氧气耗竭引起的有氧呼吸抑制 或接触一氧化氮(NO)和一氧化碳。结核分枝杆菌(Mtb)通过以下途径在这种压力下存活下来 诱导一个由~50个基因组成的调节子，在适应的同时驱动细菌以非复制状态进入 它的新陈代谢，以维持能量水平和氧化还原平衡与生存相适应的缺乏 呼吸。因此，控制该调节子表达的调节器的抑制物正在积极地 寻求它们在联合使用时缩短结核病治疗和降低复发率的潜力 使用标准护理抗生素。 我们最近的研究表明，MABSC和MAC的同源调控因子发挥着与MTB相似的功能。 MABSC中该调节子的遗传和药物破坏导致了对生物被膜形成的抑制 在低氧条件下，细菌活力下降，耐药逆转。最重要的是，两种抑制剂 我们鉴定的MABSC中的这个调节子对感染MABSC的小鼠具有显著的杀菌活性 除了增强联合使用的标准护理抗生素的活性外。因为这两种抑制剂 要么用于临床，要么处于第二阶段临床试验，它们提供了可能是短暂的再利用机会 去诊所的路线。 这些令人兴奋的发现促使我们提交了这份赠款申请，在这份申请中，我们提议彻底 破译这些抑制剂治疗和辅助治疗的潜在机制 MABSC(目标1)，并确定是否可以将同样的治疗策略应用于MAC(目标2)。

Abstract The prevalence of pulmonary nontuberculous mycobacterial (NTM) infections caused by Mycobacterium abscessus complex (MABSC) and Mycobacterium avium complex (MAC) species is increasing worldwide and poses a particular threat to susceptible individuals with structural or functional lung conditions such as cystic fibrosis, chronic obstructive pulmonary disease and bronchiectasis. The intrinsic recalcitrance of these pathogens to chemotherapeutic treatments and alarming treatment failure rates place a high priority on the development of more effective treatment approaches. The ability of MABSC and MAC to persist intracellularly and extracellularly within granulomatous lesions in a non-replicating state is likely to contribute to the drug tolerance of these microorganisms and to treatment failure in chronically-infected individuals. Further compounding this problem is the ability of MABSC and MAC to form what appears to be genetically programmed biofilms during human pulmonary infections. A common stress faced by intra- and extracellular NTM inside activated immune cells, in avascular necrotic and caseous regions of granulomas, and within microaggregates or biofilms is the inhibition of aerobic respiration caused by O2 depletion or exposure to nitric oxide (NO) and carbon monoxide. M. tuberculosis (Mtb) is known to survive this stress by inducing a regulon of ~50 genes that drives the entry of the bacterium in a non-replicating state while adapting its metabolism to maintain energy levels and a redox balance compatible with survival in the absence of respiration. Accordingly, inhibitors of the regulator which controls the expression of this regulon are actively being sought for their potential to shorten tuberculosis treatment and lower relapse rates when used in combination with standard-of-care antibiotics. Our recent studies indicate that the orthologous regulators of MABSC and MAC play a similar function as in Mtb. Genetic and pharmacological disruption of this regulator in MABSC led to inhibition of biofilm formation in addition to decreasing bacterial viability and reversing drug tolerance under hypoxia. Most importantly, two inhibitors of this regulator in MABSC which we identified showed significant bactericidal activity in MABSC-infected mice in addition to potentiating the activity of standard-of-care antibiotics used in combination. Since these two inhibitors are either clinically-used or in phase II clinical trial, they offer repurposing opportunities that could be a short route to the clinic. These exciting findings stimulated the submission of this grant application in which we propose to thoroughly decipher the mechanisms underlying the therapeutic and adjunct therapeutic benefits of these inhibitors in MABSC (Aim 1) and to determine whether the same therapeutic strategy may be applied to MAC (Aim 2).