Phenylacetic acid catabolism, a novel stress-response pathway in Acinetobacter baumannii

苯乙酸分解代谢，鲍曼不动杆菌中一种新的应激反应途径

• 批准号: 10621274
• 负责人: Mario Feldman
• 金额: $ 67.11万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-12 至 2027-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10621274
• 关键词: Acinetobacter; Acinetobacter Infections; Acinetobacter baumannii; Acute; Adherence; Affect; Anabolism; Antibiotic Therapy; Antibiotic susceptibility; Antibiotics; Auxins; Biological Assay; Biological Process; Catabolism; Categories; Cell physiology; Cells; Centers for Disease Control and Prevention (U.S.); Clinical; Clinical Research; Collaborations; Cytoplasm; Disease; Environment; Enzymes; Epithelial Cells; Exposure to; Extracellular Matrix Proteins; Foundations; Future; Gene Expression; Genes; Genetic; Genetic Transcription; High Pressure Liquid Chromatography; Hospitals; Hydrogen Peroxide; Hypoxia; Infection; Iron; Lead; Life; Lung infections; Measures; Mediating; Microbial Biofilms; Modeling; Molecular; Multi-Drug Resistance; Multidrug-resistant Acinetobacter; Mus; Mutagenesis; Mutate; Mutation; Operon; Osmosis; Oxidative Stress; Pathogenesis; Pathway interactions; Phagocytes; Phenotype; Phenylalanine; Physiological; Pilum; Plants; Process; Production; Property; Regulation; Reporter; Repression; Research Priority; Role; Second Messenger Systems; Signal Pathway; Signal Transduction; Signaling Molecule; Stress; Sulfamethoxazole; System; Testing; Therapeutic; Trimethoprim; Urinary tract infection; Virulence; Work; World Health Organization; antibiotic tolerance; antimicrobial; biological adaptation to stress; catheter associated UTI; clinically relevant; combat; gene repression; genetic regulatory protein; mouse model; mutant; novel; novel therapeutic intervention; pathogen; pathogenic bacteria; phenylacetic acid; pressure; prevent; research and development; resistance mechanism; response; stress tolerance; stressor; therapy outcome; transcriptomics

PROJECT SUMMARY/ABSTRACT Multidrug resistant (MDR) infections caused by the bacterial pathogen Acinetobacter baumannii are increasing at alarming rates. Currently, over 60 % of global A. baumannii clinical isolates are MDR, leading the Centers for Disease Control and Prevention and the World Health Organization to categorize it as a top priority for the research and development of new antimicrobial therapies. In addition to accumulating resistance mechanisms, A. baumannii strains develop tolerance to antibiotics, which can frequently lead to poor therapeutic outcomes even with antibiotic susceptible strains. However, the mechanisms used by A. baumannii to adapt to and tolerate hostile conditions remain largely unknown. We found that A. baumannii employs a novel stress response pathway in which phenylacetic acid (PAA), a metabolite derived from phenylalanine catabolism, acts as a signaling molecule. We established that, in the presence of sub-inhibitory concentrations of different antibiotics, such as trimethoprim/sulfamethoxazole, A. baumannii dramatically increases the transcription of the paa operon which encodes enzymes required to degrade PAA. Conversely, other conditions, like hydrogen peroxide treatment, lead to a repression of the paa operon. The regulation of the paa operon triggers a physiological adaptive response that includes the modulation of pili biosynthesis and biofilm formation. Importantly, we found that artificial augmentation of PAA levels, through the addition of commercially available PAA-derivatives or mutations in PAA degradative genes, disrupts this response Furthermore, mutating initial steps of PAA degradation leads to increased sensitivity to antibiotics and oxidative stress in multiple strains. Here we propose to use our expertise in A. baumannii genetics and pathogenesis to investigate the PAA-mediated stress response in Acinetobacter and determine its importance in virulence. We will determine the breadth of PAA signaling using reporter assays, and we will explore PAA-mediated changes in cell physiology by profiling gene expression under different stress conditions. Further, we will characterize the PAA-dependent mechanisms of cell signaling under stress by measuring cellular levels of PAA and determining the role of important regulatory proteins in this cascade. Finally, we will test the virulence of strains unable to regulate PAA levels in the catheter-associated urinary tract infection and lung infection murine models. Our work will establish the role of PAA as a key regulatory molecule in A. baumannii, determine the biological processes regulated by PAA, and uncover the mechanisms by which PAA triggers adaptations to promote survival under stress. Understanding the fundamental aspects of the PAA stress response will provide a foundation to future clinical studies.

项目摘要/摘要 由细菌病原体鲍曼不动杆菌引起的多药耐药（MDR）感染正在增加 以惊人的速度。目前，全球60%以上的A.鲍曼不动杆菌临床分离株是MDR， 疾病控制和预防以及世界卫生组织将其列为 研究和开发新的抗菌疗法。除了积累抗性机制外， A.鲍曼不动杆菌菌株对抗生素产生耐受性，这通常会导致不良的治疗结果 即使是对抗生素敏感的菌株。然而，A.鲍曼不动杆菌适应和耐受 敌对情况基本上仍不清楚。我们发现A.鲍曼不动杆菌采用了一种新的应激反应 苯乙酸（PAA），一种来源于苯丙氨酸催化剂的代谢产物， 信号分子我们确定，在不同抗生素的亚抑菌浓度存在下， 如甲氧苄啶/磺胺甲恶唑，A.鲍曼不动杆菌显著增加PAA操纵子的转录 其编码降解PAA所需的酶。相反，其他条件，如过氧化氢 处理，导致PAA操纵子的抑制。paa操纵子的调节触发了一种生理性的 适应性反应，包括调节皮利生物合成和生物膜形成。重要的是，我们发现 通过添加市售PAA衍生物或 PAA降解基因的突变，破坏了这种反应。 降解导致多种菌株对抗生素和氧化应激的敏感性增加。在这里我们建议 利用我们在A.鲍曼不动杆菌遗传学和发病机制，以研究PAA介导的应激反应 在不动杆菌属中，并确定其在毒力中的重要性。我们将确定PAA信号的广度，使用 报告基因分析，我们将探讨PAA介导的细胞生理学的变化，通过分析基因表达 在不同的压力条件下。此外，我们将描述PAA依赖的细胞信号传导机制 通过测量PAA的细胞水平和确定重要的调节蛋白在这一过程中的作用， 级联。最后，我们将测试无法调节PAA水平的菌株在导管相关性 尿路感染和肺部感染小鼠模型。我们的工作将确立临时机场管理局的作用， A.鲍曼不动杆菌，确定PAA调节的生物过程，并揭示 PAA触发适应以促进在压力下生存的机制。了解 PAA应激反应的基本方面将为未来的临床研究提供基础。