Coordinate Regulation of Salmonella Virulence and Antimicrobial Resistance by MarR Transcription Factors

MarR 转录因子协调调节沙门氏菌毒力和抗菌素耐药性

• 批准号: 10624306
• 负责人: Ferric C Fang
• 金额: $ 49.47万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10624306
• 关键词: Affinity; Antibiotic Resistance; Antibiotics; Antimicrobial Resistance; Bacteria; Bacterial Infections; Binding Sites; Data; Disease; Drug Efflux; Drug resistance; Evolution; Family; Genes; Genetic; Genetic Transcription; Health; Human; In Vitro; Ligands; Link; Metabolic; Metabolism; Metabolite Interaction; Methods; Mutation; Operon; Phenocopy; Phenotype; Prevention; Proteins; Regulation; Regulon; Repression; Salmonella; Salmonella infections; Salmonella typhimurium; Signal Transduction; Transcription Repressor; Virulence; bacterial metabolism; carboxylate; carboxylation; comparative; efflux pump; enteric pathogen; in vivo; insight; metabolomics; new therapeutic target; response; transcription factor; virulence gene

SUMMARY. MarR (Multiple antibiotic resistance Repressor) proteins comprise an ancient family of transcription factors that are widely conserved in bacteria. In the enteric pathogen Salmonella Typhimurium, MarR is a negative regulator of the AcrAB-TolC drug efflux pump, while another MarR transcription factor called SlyA is a counter-silencer required for the expression of horizontally-acquired virulence genes. We have recently shown that despite its divergent function, SlyA shares with MarR the ability to undergo allosteric modulation by aromatic carboxylate molecules and can influence the mar phenotype by repressing the marRAB operon. Inactivation of TolC, an essential component of the AcrAB and other RND-family efflux pumps, phenocopies a slyA mutation, reducing the expression of Salmonella virulence genes. This suggests that efflux regulates the levels of an endogenous metabolite that interacts with SlyA, which in turn controls MarR expression, completing a regulatory circuit that coordinately links antimicrobial resistance, virulence, and bacterial metabolism. This proposal investigates the hypothesis that Salmonella antimicrobial resistance and virulence are coordinately regulated in response to metabolic signals by the MarR and SlyA transcription factors through the following specific aims: (1) Identification of endogenous ligand(s) that modulate MarR/SlyA activity. Preliminary data indicate that SlyA-interacting ligand(s) are aromatic carboxylates. Specific endogenous ligands will be identified by genetic and metabolomic methods and characterized with regard to affinity and allosteric inhibition. (2) Functional characterization of MarR-SlyA-TolC regulatory interactions in Salmonella antimicrobial resistance and virulence. The contribution of the MarR-SlyA regulatory network to Salmonella phenotypic antimicrobial resistance and virulence will be assessed in vitro and in vivo. (3) Comparative analysis of the MarR and SlyA regulons. MarR/SlyA-regulated genes and binding sites will be comprehensively identified to determine the regulatory requirements for repression and counter-silencing, respectively, and to elucidate the mechanisms of transcriptional network evolution. These studies will provide important insights into a central regulatory network linking bacterial virulence, drug resistance, and metabolism, which can lead to the identification of new therapeutic targets for the prevention or treatment of bacterial infections.

概括。 MarR（多重抗生素耐药性阻遏蛋白）蛋白包含一个古老的转录家族 细菌中广泛保守的因子。在肠道病原体鼠伤寒沙门氏菌中，MarR 是一种 AcrAB-TolC 药物外排泵的负调节因子，而另一个称为 SlyA 的 MarR 转录因子是 水平获得性毒力基因表达所需的反沉默子。我们最近展示了 尽管其功能不同，SlyA 与 MarR 都具有通过芳香族化合物进行变构调节的能力 羧酸盐分子，并可以通过抑制 marRAB 操纵子来影响 mar 表型。失活 TolC 是 AcrAB 和其他 RND 家族外排泵的重要组成部分，可复制 slyA 突变， 减少沙门氏菌毒力基因的表达。这表明外排调节 与 SlyA 相互作用的内源代谢物，SlyA 反过来控制 MarR 表达，完成调节 协调连接抗菌素耐药性、毒力和细菌代谢的回路。 该提案研究了沙门氏菌抗菌素耐药性和毒力与沙门氏菌耐药性和毒力相关的假设。 MarR 和 SlyA 转录因子对代谢信号的协调调节 通过以下具体目标： (1) 鉴定调节 MarR/SlyA 活性的内源配体。初步数据表明 SlyA 相互作用的配体是芳香族羧酸盐。特定的内源配体将通过遗传鉴定 和代谢组学方法，并以亲和力和变构抑制为特征。 (2) 沙门氏菌抗菌药物中 MarR-SlyA-TolC 调节相互作用的功能表征 抵抗力和毒力。 MarR-SlyA 调控网络对沙门氏菌表型的贡献 将在体外和体内评估抗菌药物耐药性和毒力。 (3)MarR和SlyA调节子的比较分析。 MarR/SlyA 调节的基因和结合位点将 全面识别以确定镇压和反沉默的监管要求， 分别，并阐明转录网络进化的机制。 这些研究将为连接细菌毒力、药物的中央监管网络提供重要见解。 抵抗力和代谢，这可以导致确定新的治疗靶点以预防或 治疗细菌感染。