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 由细菌病原体鲍曼尼杆菌引起的多药耐药性（MDR）感染正在增加 以惊人的速度。目前，超过60％的全球baumannii临床分离株是MDR，领导了中心 疾病控制和预防以及世界卫生组织将其归类为重中之重 新抗菌疗法的研究和开发。除了积累抗性机制外， 鲍曼尼菌菌株会产生对抗生素的耐受性，这通常会导致治疗结果不佳 即使有抗生素易感性菌株。但是，鲍曼尼曲霉使用的机制适应并耐受 敌对条件在很大程度上仍然未知。我们发现A. baumannii采用了一种新颖的压力反应 苯乙酸（PAA）是一种衍生自苯丙氨酸分解代谢的代谢物的苯乙酸（PAA），充当 信号分子。我们确定，在存在不同抗生素的亚抑制浓度的情况下， 例如甲氧苄啶/磺胺甲恶唑，鲍曼尼曲霉大大增加了PAA操纵子的转录 它编码降解PAA所需的酶。相反，其他条件，例如过氧化氢 治疗，导致对PAA操纵子的抑制。 PAA操纵子的调节会触发生理 适应性反应，包括调节pili生物合成和生物膜形成。重要的是，我们发现 通过添加市售的PAA衍生物或 PAA降解基因中的突变，进一步破坏了这种反应，突变了PAA的初始步骤 降解会导致对抗生素的敏感性增加，并导致多种菌株中的氧化应激。我们在这里提出 利用我们在鲍曼尼曲霉的遗传学和发病机理中的专业知识来研究PAA介导的应激反应 在动杆菌中，确定其在毒力中的重要性。我们将使用 记者测定法，我们将通过分析基因表达来探索PAA介导的细胞生理变化 在不同的压力条件下。此外，我们将表征细胞信号的PAA依赖性机制 在压力下通过测量PAA的细胞水平并确定重要调节蛋白在此中的作用 级联。最后，我们将测试无法调节导管相关的PAA水平的菌株的毒力 尿路感染和肺部感染鼠模型。我们的工作将确定PAA作为关键的角色 鲍曼尼曲霉中的调节分子，确定由PAA调节的生物学过程，并发现 PAA触发适应以促进压力下生存的机制。了解 PAA应力反应的基本方面将为未来的临床研究提供基础。