Discovery and characterization of bacterial cell envelope assembly and remodeling networks that modulate tolerance to antibiotics

调节抗生素耐受性的细菌细胞包膜组装和重塑网络的发现和表征

• 批准号: 10711329
• 负责人: Josue Flores-Kim
• 金额: $ 41.88万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10711329
• 关键词: Affect; Antibiotics; Bacteria; Bacterial Physiology; Biogenesis; Biological Models; Cell Enlargement; Cell Shape; Cell Wall; Cell division; Cells; Cellular Morphology; Complex; Cytolysis; Enzymes; Equilibrium; Goals; Growth; Health; Human; Infection; Laboratories; Link; Maintenance; Membrane; Molecular; Multi-Drug Resistance; N-Acetylmuramoyl-L-alanine Amidase; Osmosis; Pathogenesis; Pathway interactions; Peptide Hydrolases; Peptidoglycan; Physiological; Polymers; Post-Translational Protein Processing; Process; Proteolysis; Regulation; Research; Role; Signal Transduction; Streptococcus pneumoniae; Structure; System; Teichoic Acids; Therapeutic Intervention; Virulence; antibiotic tolerance; cell envelope; cell growth; insight; lipoteichoic acid; model organism; new therapeutic target; novel; pathogen; respiratory pathogen; therapeutic development

Abstract The bacterial cell envelope is a complex and dynamic multilayered structure essential for cell growth and division. The structural layer of the envelope, known as the cell wall or peptidoglycan (PG), determines cell shape and is essential for survival because it protects bacteria from osmotic lysis. The action of PG synthases, which add new material for the enlargement of the cell wall, and PG hydrolases, which create space for expansion of the PG mesh-like structure, are both necessary for growth. Some of our most powerful and successful antibiotics target PG synthases and derive their efficacy from not only inhibiting cell wall assembly, but also by causing cell lysis through the active destruction of the cell wall by PG hydrolases. Because of their potential to cause cell lysis, it has long been appreciated that bacteria must possess robust mechanisms to control when and where PG hydrolases are activated. However, the molecular details underlying these regulatory processes are lacking. Research in my laboratory focuses on uncovering and characterizing regulatory systems controlling PG hydrolase activity during normal growth, and how antibiotics short-circuit this regulation to trigger cell lysis. Using the human respiratory pathogen Streptococcus pneumoniae as a model organism, we found that PG hydrolases are controlled by two cell envelope polymers known as teichoic acids (TAs): membrane-linked lipoteichoic acids (LTAs) and cell wall-anchored teichoic acids (WTAs). Characterization of novel enzymes involved in TA synthesis and remodeling revealed that cell-wall targeting antibiotics hyperactivate PG hydrolases by disrupting the normal mechanisms that balance the levels of WTAs and LTAs in the cell envelope. Current studies in my laboratory indicate that the levels of TAs are controlled by a complex regulatory network involving post- translational modifications and targeted proteolysis. We also discovered that the modulation of the TA levels in the cell envelope has significant impacts on cell morphology, growth, and tolerance to antibiotics. However, many aspects of this regulation and synthesis and remodeling pathways remain unknown. Therefore, the goals of this proposal are to (i) identify signals and pathways that modulate LTA biogenesis and characterize how antibiotics subvert them; (ii) determine the physiological roles and regulation of a widely-conserved protease and characterize how antibiotics hyperactivate its activity to disrupt LTA biogenesis; (iii) characterize the regulation of a novel WTA remodeling enzyme, and uncover how S. pneumoniae uses WTA levels to control lysis and promote growth. The results generated by this research will provide fundamental insights into broadly relevant principles for envelope assembly and maintenance in S. pneumoniae and related bacteria. S. pneumoniae has become an alarming multidrug-resistant health threat. Therefore, novel antibiotics that target S. pneumoniae are critically needed. The studies proposed here will reveal general mechanisms by which bacteria remodel their envelopes to survive antibiotic exposure and uncover new targets for therapeutic intervention.

摘要 细菌的细胞膜是一个复杂的、动态的多层结构，对细胞的生长和分裂是必不可少的。 包膜的结构层，称为细胞壁或肽聚糖(PG)，决定细胞的形状，是 对于生存是必不可少的，因为它能保护细菌免受渗透溶解。PG合成酶的作用，它增加了新的 用于扩大细胞壁的材料，以及为PG的扩张创造空间的PG水解酶 网状结构，都是生长所必需的。我们一些最有效和最成功的抗生素靶标 PG合成酶，不仅通过抑制细胞壁组装，还通过引起细胞裂解来获得它们的功效 通过PG水解酶对细胞壁的主动破坏。因为它们有可能导致细胞裂解，所以它 长期以来，人们一直认为细菌必须拥有强大的机制来控制何时何地的PG 水解酶被激活。然而，这些调控过程背后的分子细节尚不清楚。 我实验室的研究重点是发现和描述控制PG的监管系统 水解酶在正常生长过程中的活性，以及抗生素如何短路这一调节来触发细胞溶解。vbl.使用 以人类呼吸道病原体肺炎链球菌为模式生物，我们发现PG水解酶 由两种称为磷壁酸(TA)的细胞膜聚合物控制：膜连接的脂磷壁酸 (LTAS)和细胞壁锚定磷壁酸(WTAS)。TA相关新型酶的特性研究 合成和重塑表明，靶向抗生素的细胞壁通过破坏PG水解酶来激活PG水解酶 平衡细胞膜中WTAs和Ltas水平的正常机制。我的研究现状 实验室表明，TA水平受一个复杂的调控网络控制，涉及后- 翻译修饰和靶向蛋白降解。我们还发现，体内TA水平的调制 细胞被膜对细胞形态、生长和对抗生素的耐受性有重要影响。然而，许多人 这种调节、合成和重塑途径的某些方面仍不清楚。因此，这一行动的目标是 建议是：(I)确定调节LTA生物发生的信号和途径，并表征抗生素如何 颠覆它们；(Ii)确定广泛保守的蛋白水解酶的生理作用和调节 表征抗生素如何过度激活其活性以扰乱LTA的生物发生；(Iii)表征调控 一种新的WTA重塑酶，并揭示肺炎链球菌如何利用WTA水平来控制裂解和 促进增长。这项研究产生的结果将为广泛相关的 肺炎链球菌及相关细菌的包膜组装和维护原则。肺炎链球菌有 成为一个令人担忧的对多种药物具有耐药性的健康威胁。因此，针对肺炎链球菌的新型抗生素是 这是急需的。这里提出的研究将揭示细菌重塑其自身的一般机制 在抗生素暴露中幸存下来的信封，并发现治疗干预的新靶点。