The impact of pyrazinamide on metabolism in Mycobacterium tuberculosis

吡嗪酰胺对结核分枝杆菌代谢的影响

• 批准号: 10573270
• 负责人: ANTHONY D BAUGHN
• 金额: $ 45.31万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-10 至 2026-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10573270
• 关键词: Animal Model; Automobile Driving; Bacillus; Cells; Cellular Immunity; Chemosensitization; Clinical; Coenzyme A; Combined Modality Therapy; Development; Disease; Drug usage; Elements; Environment; Exposure to; Genes; Genetic Epistasis; Genetic Variation; Goals; HIV/AIDS; Human; Immune; Immunity; Impairment; In Vitro; Infection; Integration Host Factors; Interferon Type II; Investigation; Knowledge; Laboratory culture; Macrophage; Mediating; Metabolism; Microbe; Molecular; Molecular Biology; Mus; Mutation; Mycobacterium tuberculosis; Nude Mice; Nutrient; Other Genetics; Oxidative Stress; Oxygen; Phenotype; Population; Predisposition; Prodrugs; Pyrazinamide; Pyrazinamide resistance; Reactive Nitrogen Species; Reactive Oxygen Species; Recombinants; Regimen; Relapse; Resistance; Rest; Role; Signal Transduction; T cell response; T-Lymphocyte; Therapeutic; Tuberculosis; Wild Type Mouse; amidase; antimicrobial; biological adaptation to stress; cell envelope; drug action; drug discovery; improved; in vivo; loss of function mutation; mutant; mycobacterial; novel; novel strategies; pyrazinoic acid; resistance mutation; response; small molecule; stressor; treatment duration; tuberculosis drugs; tuberculosis treatment

Project Summary Pyrazinamide (PZA) is a critical component of first-line tuberculosis (TB) therapy because it has dramatically reduced relapse rates and treatment duration. PZA is weakly active in vitro, but potently sterilizing in vivo, due to its outstanding activity against slow and non-replicating populations of Mycobacterium tuberculosis that are phenotypically tolerant to most other TB drugs. Understanding the basis for the in vivo sterilizing activity of PZA represents one of the most important unmet needs in TB drug discovery. While the mode of action of PZA remains under investigation, our knowledge of factors that govern susceptibility and resistance has advanced considerably in recent years. PZA is a pro-drug that must be converted to the active form of pyrazinoic acid (POA) by the M. tuberculosis amidase PncA, and loss-of-function mutations in pncA account for at least 70% of clinical resistance. Other genetic variations associated with resistance have been described, but most have not been evaluated in isogenic strains to determine their role in resistance, and have not been assessed for association with PZA resistance in animal models of infection. Importantly, PZA lacks antitubercular activity in athymic nude mice, indicating a key role for T cell-mediated immunity in efficacy. Consistent with these observations, our lab and others have shown that PZA is inactive against M. tuberculosis in resting macrophages, but contributes to bacterial killing in macrophages activated by interferon-gamma (IFN-ɣ). Host- dependent stressors that are associated with IFN-ɣ stimulation, such as exposure to low pH, nutrient limitation and reactive oxygen species, have been implicated as contributors to PZA action. Our recent studies have revealed a central role for specific M. tuberculosis stress responses in PZA conditional susceptibility. Through these studies, we have identified a network of functions that modulates PZA susceptibility when expression of the corresponding genes is altered. We have also identified specific host factors that contribute to PZA action in macrophages and in infected mice. Based on these findings, we have identified means to bolster drug action under conditions where PZA typically lacks activity. Through this proposal, we aim to characterize novel molecular mechanisms for PZA resistance, determine host factors that modulate PZA susceptibility, and assess opportunities in host- and microbe-targeted PZA potentiation. These studies will advance our understanding of mechanisms that govern PZA susceptibility and resistance of M. tuberculosis. As a substantial proportion of TB disease results from impaired T cell responses, it is of fundamental importance to understand how these responses relate to PZA efficacy and how we can use this information to optimize PZA action in the context of impaired immunity.

项目摘要 吡嗪酰胺（PZA）是一线结核病（TB）治疗的关键组分，因为它具有显著的抗结核作用。 降低复发率和治疗时间。PZA在体外活性较弱，但在体内有效灭菌， 其对慢性和非复制型结核分枝杆菌群体的突出活性， 对大多数其他结核病药物表型耐受。了解PZA体内灭菌活性的基础 是结核病药物发现中最重要的未满足需求之一。虽然PZA的作用方式 尽管仍在调查中，但我们对控制易感性和耐药性的因素的认识已经取得了进展 近年来相当多。PZA是一种前药，必须转化为吡嗪酸的活性形式 (POA)在M。结核酰胺酶PncA，和pncA的功能丧失突变占至少70% 临床抵抗力。其他与抗性相关的遗传变异也有描述，但大多数都是 尚未在等基因菌株中进行评价，以确定其在耐药性中的作用，也尚未评估 与感染动物模型中PZA耐药性的相关性。重要的是，PZA缺乏抗结核活性， 无胸腺裸鼠，表明T细胞介导的免疫在功效中的关键作用。符合这些 通过观察，我们的实验室和其他人已经表明PZA对M是无活性的。静息期结核 巨噬细胞中的细菌，但有助于由干扰素-γ（IFN-γ）激活的巨噬细胞中的细菌杀伤。主持人- 与IFN-γ刺激相关的依赖性应激源，如暴露于低pH、营养限制 和活性氧类，已经被认为是PZA作用的贡献者。我们最近的研究 揭示了特定M. PZA条件易感性中的结核病应激反应。通过 这些研究，我们已经确定了一个网络的功能，调节PZA的易感性时，表达 相应的基因也会改变我们还确定了有助于PZA作用的特定宿主因素 在巨噬细胞和受感染的小鼠中。根据这些发现，我们已经确定了支持药物行动的方法 在PZA通常缺乏活性的条件下。通过这一建议，我们的目标是描述小说 PZA抗性的分子机制，确定调节PZA易感性的宿主因子，以及 评估宿主和微生物靶向PZA增强的机会。这些研究将推动我们的 了解管理PZA敏感性和M.结核作为 相当大比例的结核病是由受损的T细胞应答引起的， 了解这些反应与PZA疗效的关系，以及我们如何利用这些信息优化PZA 在免疫力受损的情况下采取行动。