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而动态的多层结构，对细胞生长和分裂必不可少。 信封的结构层，称为细胞壁或肽聚糖（PG），确定细胞形状，是 生存至关重要，因为它可以保护细菌免受渗透裂解。 PG合成酶的作用，增加了新的 用于扩大细胞壁和PG水解酶的材料，这些材料为PG膨胀提供了空间 网状结构都是生长所必需的。我们一些最强大，最成功的抗生素目标 PG合酶不仅从抑制细胞壁组装中，而且通过引起细胞裂解而获得疗效 通过PG水解酶对细胞壁的主动破坏。由于它们可能引起细胞裂解，因此 长期以来一直认为细菌必须具有强大的机制来控制何时何地 水解酶被激活。但是，缺乏这些调节过程的分子细节。 我的实验室的研究重点是发现和表征控制PG的监管系统 正常生长过程中的水解酶活性，以及​​抗生素如何短路这种调节引发细胞裂解。使用 人类呼吸道病原体肺炎肺炎作为模型生物，我们发现PG水解酶 由称为Teichoic Acid（TAS）的两个细胞包膜聚合物控制：膜连接的脂甲酸 （LTA）和细胞壁锚定的Teichoic酸（WTA）。参与TA的新酶的表征 合成和重塑表明，细胞壁靶向抗生素过度激活PG水解酶通过破坏PG水解酶 平衡细胞包膜中WTA和LTA水平的正常机制。当前的研究 实验室表明TA的水平受到复杂的调节网络的控制，该网络涉及 翻译修饰和靶向蛋白水解。我们还发现，在 细胞包膜对细胞形态，生长和对抗生素的耐受性有重大影响。但是，很多 该调节，合成和重塑途径的各个方面仍然未知。因此，目标的目标 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 颠覆它们； （ii）确定广泛保存的蛋白酶的生理作用和调节 表征抗生素如何过度激活其活性以破坏LTA生物发生； （iii）表征该法规 一种新型的WTA重塑酶，并发现肺炎链球菌如何使用WTA水平来控制裂解和 促进增长。这项研究产生的结果将提供有关广泛相关的基本见解 肺炎链球菌和相关细菌中包膜组装和维护的原理。 S.肺炎有 成为令人震惊的多药健康威胁。因此，靶向肺炎链球菌的新型抗生素是 至关重要的是。这里提出的研究将揭示细菌重塑其的一般机制 信封可在抗生素暴露中生存，并发现治疗干预的新靶标。