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.

抽象的 细菌细胞包膜是一种复杂且动态的多层结构，对于细胞生长和分裂至关重要。 包膜的结构层，称为细胞壁或肽聚糖 (PG)，决定细胞形状，并且是 对于生存至关重要，因为它可以保护细菌免受渗透裂解。 PG合酶的作用，增加了新的 用于扩大细胞壁的材料和 PG 水解酶，为 PG 的扩张创造空间 网状结构，都是生长所必需的。我们一些最强大和最成功的抗生素靶点 PG 合酶的功效不仅来自抑制细胞壁组装，还来自引起细胞裂解 通过 PG 水解酶主动破坏细胞壁。由于它们可能导致细胞裂解， 长期以来人们认识到细菌必须拥有强大的机制来控制 PG 的时间和地点 水解酶被激活。然而，缺乏这些调控过程背后的分子细节。 我实验室的研究重点是揭示和表征控制 PG 的调控系统 正常生长期间的水解酶活性，以及​​抗生素如何短路这种调节以引发细胞裂解。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 (LTA) 和细胞壁锚定磷壁酸 (WTA)。 TA 相关新型酶的表征 合成和重塑表明，靶向抗生素的细胞壁通过破坏 PG 水解酶来过度激活 平衡细胞膜中 WTA 和 LTA 水平的正常机制。我目前的研究 实验室表明，TA 的水平是由一个复杂的调控网络控制的，该网络涉及后期 翻译修饰和靶向蛋白水解。我们还发现 TA 水平的调节 细胞被膜对细胞形态、生长和对抗生素的耐受性有重大影响。然而，许多 这种调节、合成和重塑途径的各个方面仍然未知。因此，本次活动的目标 建议是 (i) 确定调节 LTA 生物发生的信号和途径，并描述抗生素如何 颠覆他们； (ii) 确定广泛保守的蛋白酶的生理作用和调节； 描述抗生素如何过度激活其活性以破坏 LTA 生物发生； (iii) 描述监管的特征 一种新型 WTA 重塑酶的研究，并揭示肺炎链球菌如何利用 WTA 水平来控制裂解和 促进生长。这项研究产生的结果将为广泛相关的问题提供基本见解 肺炎链球菌和相关细菌的包膜组装和维护原理。肺炎链球菌有 成为令人震惊的多重耐药性健康威胁。因此，针对肺炎链球菌的新型抗生素是 迫切需要。这里提出的研究将揭示细菌重塑其自身的一般机制 信封以在抗生素暴露中生存并发现治疗干预的新目标。