Cell surface biogenesis in Streptococcus pneumoniae

肺炎链球菌的细胞表面生物合成

• 批准号: 10543050
• 负责人: DAVID Z RUDNER
• 金额: $ 43.01万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10543050
• 关键词: Adopted; Antibiotic Therapy; Antibiotics; Area; Autolysis; Bacillus subtilis; Bacteria; Biochemical; Biochemistry; Biogenesis; Biological; Biology; Cell Cycle; Cell Wall; Cell surface; Cells; Cessation of life; Child; Cleaved cell; Complex; Cytolysis; Development; Disease; Drug Targeting; Drug resistance; Elderly; Enzymes; Escherichia coli; Exposure to; Future; Genetic; Genetic Screening; Genetic study; Gram-Positive Bacteria; Growth; Homologous Gene; Hydrolase; Incidence; Infection; Innate Immune System; Joints; Knowledge; Laboratories; Life; Membrane Proteins; Methods; Microscopy; Modeling; Modernization; Molecular Profiling; Morphogenesis; Morphology; N-Acetylmuramoyl-L-alanine Amidase; Organism; Pathogenesis; Pathway interactions; Pattern; Penicillin-Binding Proteins; Peptides; Peptidoglycan; Peptidoglycan glycosyltransferase; Peptidyltransferase; Pharmaceutical Preparations; Phase; Phosphorylation; Phosphotransferases; Play; Pneumococcal vaccine; Pneumonia; Polymers; Polysaccharides; Process; Proteins; Publishing; Reaction; Regulation; Research; Resistance; Rod; Role; Shapes; Staphylococcus aureus; Streptococcus pneumoniae; Stress; Structure; Surface; System; Teichoic Acids; Testing; Vaccine Therapy; Vaccines; Virulence; Virulence Factors; Work; beta-Lactams; cell envelope; crosslink; enzyme activity; experimental study; genetic analysis; human pathogen; in vitro activity; insight; lipoteichoic acid; model organism; novel; pathogen; pathogenic bacteria; polymerization; polypeptide; prevent; programs; reconstitution; response; success; therapeutic development; vaccine-induced immunity; virtual

PROJECT SUMMARY The cell surface of pathogenic bacteria contains many key virulence factors that are used to interface with the host. Cell surface polymers also contain the molecular signatures recognized by the innate immune system to activate a defensive response, and surface molecules or their biogenesis pathways serve as important targets for many of our most effective vaccine and antibiotic therapies. A better understanding of the mechanisms responsible for bacterial surface assembly will therefore impact virtually all areas of pathogenesis research and inform the development of new treatments for infections. Although some aspects of cell surface assembly can be inferred from studies of non-pathogenic organisms, results from the models will never be entirely predictive. Departures from the model are likely to be especially pronounced for pathogens like Streptococcus pneumoniae (Sp) that adopt a different (ovoid) morphology and grow via distinct mechanisms from rod-shaped organisms like Escherichia coli and Bacillus subtilis where studies of cell surface assembly have traditionally been investigated. Sp is a major cause of life-threatening disease in young children and older adults, and the incidence of drug-resistant infections with this organism is on the rise. The efficacy of the polyvalent Sp vaccine is also declining due to the emergence of strains with altered surface polysaccharides that escape vaccine-induced immunity. It is therefore important to identify new ways of disabling Sp growth. To do so, we have initiated a program to investigate cell surface assembly in Sp that leverages the joint expertise of the Rudner and Bernhardt laboratories in cell wall biogenesis, gram-positive biology, microscopy, biochemistry, and genetics. Importantly, our approach is not limited to the characterization of homologs of well-studied cell morphogenesis factors from the rod-shaped model organisms. Instead we are taking advantage of forward genetic screens powered by modern sequencing methods to discover new players and biological mechanisms involved in Sp growth. Our preliminary genetic analyses have uncovered two novel regulators of the penicillin- binding proteins (PBPs) of Sp. These are the first set of factors identified in gram-positive bacteria that control the activity of these critical cell wall synthases. The first aim of the project will investigate the mechanism by which these factors modulate PBP activity and connect the function of these enzymes with other components of the morphogenetic system. In addition to controlling PBP activity, proper surface assembly also requires the regulation of enzymes that cleave the cell wall. The factors governing the activity of these enzymes are poorly understood in all bacteria. Our second aim will build on promising results where we have identified a regulatory role for surface polymers called lipoteichoic acids (LTAs) in controlling the activity of the cell wall hydrolase LytA responsible for Sp cell lysis following beta-lactam treatment. Overall, our results promise to uncover new ways of either blocking cell wall assembly or triggering autolysis for therapeutic development.

项目摘要 致病细菌的细胞表面包含许多关键的毒力因子，用于与 主持人。细胞表面聚合物还包含由先天免疫系统识别为的分子特征 激活防御响应，表面分子或其生物发生途径是重要目标 对于我们许多最有效的疫苗和抗生素疗法。更好地理解机制 因此，负责细菌表面组装将影响发病机理研究的所有领域， 告知开发新的感染治疗方法。尽管细胞表面组件的某些方面可以 可以从非致病生物的研究中推断出来，模型的结果永远不会完全预测。 与链球菌等病原体的偏离可能特别明显 肺炎（SP）采用不同的（卵形）形态并通过杆状的不同机制生长 传统上对细胞表面组装研究的生物等生物等有机体，其中 被调查。 SP是幼儿和老年人威胁生命的疾病的主要原因， 这种生物体耐药感染的发病率正在上升。多价SP的功效 疫苗由于表面多糖改变的菌株的出现而在下降 疫苗诱导的免疫力。因此，重要的是确定禁用SP增长的新方法。为此，我们 已经启动了一个计划，以调查SP中的细胞表面组件，该程序利用了联合专业知识 细胞壁生物发生，革兰氏阳性生物学，显微镜，生物化学， 和遗传学。重要的是，我们的方法不仅限于精心研究细胞的同源物的表征 棒状模型生物的形态发生因子。相反，我们正在利用前进 由现代测序方法提供动力的遗传筛选，以发现新玩家和生物学机制 参与SP增长。我们的初步遗传分析发现了两个青霉素的新型调节剂 Sp的结合蛋白（Pbps）。这些是革兰氏阳性细菌中发现的第一组因素 这些关键细胞壁合酶的活性。该项目的第一个目的将通过 这些因素调节PBP活性并将这些酶的功能与其他成分联系起来 形态发生系统。除了控制PBP活动外，适当的表面组件还需要 调节裂解细胞壁的酶。控制这些酶活性的因素很差 在所有细菌中都了解。我们的第二个目标将以有希望的结果为基础 表面聚合物的作用，称为脂甲酸（LTA）在控制细胞壁水解酶的活性中 β-内酰胺治疗后负责SP细胞裂解的Lyta。总体而言，我们的结果有望揭示新的 阻止细胞壁组件或触发自溶以进行治疗发育的方法。

项目成果

WhyD tailors surface polymers to prevent premature bacteriolysis and direct cell elongation in Streptococcus pneumoniae.

• DOI: 10.7554/elife.76392
• 发表时间: 2022-05-20
• 期刊: ELIFE
• 影响因子: 7.7
• 作者: Flores-Kim, Josue;Dobihal, Genevieve S.;Bernhardt, Thomas G.;Rudner, David Z.
• 通讯作者: Rudner, David Z.

MacP bypass variants of Streptococcus pneumoniae PBP2a suggest a conserved mechanism for the activation of bifunctional cell wall synthases.

• DOI: 10.1128/mbio.02390-23
• 发表时间: 2023-12-19
• 期刊: mBio
• 影响因子: 6.4