A novel mechanism of rifamycin resistance in Mycobacterium abscessus mediated by a putative helicase

由假定的解旋酶介导的脓肿分枝杆菌利福霉素耐药性的新机制

• 批准号: 10302960
• 负责人: Pallavi Ghosh
• 金额: $ 22.67万
• 依托单位: WADSWORTH CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-20 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10302960
• 关键词: ADP Ribose Transferases; Actinobacteria class; Acute respiratory failure; Affinity Chromatography; Antibiotic Resistance; Antibiotics; Bacillus subtilis; Bacteria; Bacterial RNA; Binding; Binding Proteins; Biological Assay; Chronic; Chronic Obstructive Airway Disease; Clinical; Cystic Fibrosis; DNA; DNA-Directed RNA Polymerase; Dose; Elements; Enzymes; Exposure to; FDA approved; Future; Genes; Genetic Transcription; Genome; Genus Mycobacterium; Growth; Hypersensitivity; In Vitro; Infection; Investigation; Laboratories; Lead; Longitudinal Studies; Lung; Lung infections; Mediating; Microbial Antibiotic Resistance; Mutation; Mycobacterium Infections; Mycobacterium abscessus; Mycobacterium tuberculosis; Nightmare; Pathway interactions; Patients; Pharmaceutical Preparations; RNA chemical synthesis; Regulation; Replication Initiation; Reporter; Resistance; Rifabutin; Rifampicin resistance; Rifampin; Rifamycins; Skin Tissue; Soft Tissue Infections; Transcriptional Regulation; Tuberculosis; analog; antimicrobial; design; genetic regulatory protein; helicase; inhibitor/antagonist; insight; lung injury; mouse model; mutant; non-tuberculosis mycobacteria; novel; prevent; resistance gene; resistance mechanism; therapeutic development; transcription factor

Project Summary: Mycobacterium abscessus (Mab) is a rapidly growing NTM causing skin and soft tissue infections as well as pulmonary infections in patients with chronic lung damage. Mab stands apart as one of the most antibiotic resistant microbial species, making its infections incredibly difficult to treat. Particularly striking is its resistance to rifampicin (RIF), a frontline drug for many mycobacterial infections including tuberculosis. RIF inhibits global RNA synthesis by binding to the b-subunit of bacterial RNA polymerase; additionally it is also known to inhibit replication initiation due to an inhibition of dnaA expression. The intrinsic RIF resistance in Mab has so far been attributed to the presence of an ADP-ribosyltransferase (Arr) activity that ribosylates RIF leading to its inactivation. However, we have recently identified an additional determinant, MAB_3189c - a putative helicase, that confers high levels of RIF resistance in Mab. MAB_3189c expression is RIF inducible and is likely regulated by a RIF-associated element (RAE) dependent transcription factor. In this project we will determine the regulation and function of Mab3189c in RIF resistance. In Aim 1 we will investigate if Mab3189c mediates RIF resistance by either directly protecting RNAP against the action of RIF thereby enabling global RNA synthesis to continue, or by alleviating RIF-sensitive replication initiation at oriM thereby enabling growth in the presence of RIF. In Aim 2 we propose to identify the regulatory protein required for RAE-dependent induction of MAB_3189c. The findings will provide a platform for a long-term study to gain insights into Mab3189c dependent RIF resistance in Mab, and design of new strategies to treat Mab infections.

项目概要： 脓肿分枝杆菌 (Mab) 是一种快速生长的 NTM，可引起皮肤和软组织感染 以及慢性肺损伤患者的肺部感染。 Mab 是最独特的之一 抗生素耐药微生物种类，使其感染极其难以治疗。特别引人注目的是 它对利福平（RIF）具有耐药性，利福平是治疗包括结核病在内的许多分枝杆菌感染的一线药物。 RIF 通过与细菌 RNA 聚合酶的 b 亚基结合来抑制整体 RNA 合成；另外它 还已知由于抑制 dnaA 表达而抑制复制起始。内在RIF 迄今为止，Mab 中的耐药性归因于 ADP-核糖基转移酶 (Arr) 活性的存在 核糖基化 RIF 导致其失活。然而，我们最近又发现了一个额外的 决定簇 MAB_3189c - 一种推定的解旋酶，赋予 Mab 高水平的 RIF 抗性。 MAB_3189c 表达是 RIF 可诱导的，并且可能受 RIF 相关元件 (RAE) 调节 依赖性转录因子。在这个项目中，我们将确定 Mab3189c 的调控和功能 在 RIF 抵抗中。在目标 1 中，我们将研究 Mab3189c 是否通过直接介导 RIF 抗性 保护 RNAP 免受 RIF 的作用，从而使整体 RNA 合成得以继续，或者通过 减轻 oriM 处 RIF 敏感的复制起始，从而在 RIF 存在的情况下实现生长。瞄准 2 我们建议鉴定 RAE 依赖性诱导 MAB_3189c 所需的调节蛋白。这 研究结果将为长期研究提供一个平台，以深入了解 Mab3189c 依赖性 RIF Mab 的耐药性，以及治疗 Mab 感染的新策略的设计。