Quorum sensing and virulence in Gram positive pathogens: structure, function and inhibition of the agr system

革兰氏阳性病原体的群体感应和毒力：agr系统的结构、功能和抑制

• 批准号: MR/N010477/1
• 负责人: Paul Williams
• 金额: $ 218.55万
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FN010477%2F1
• 关键词: Quorum; sensing; virulence; Gram; positive

The emergence, rapid spread and persistence of multi-antibiotic resistant bacteria is considered by the WHO as one of the three greatest global threats to human health. Antimicrobial resistance (AMR) threatens the treatment and outcome of even simple infections and common medical interventions (surgery, dentistry, obstetrics) that until recently were considered low-risk. Against this backdrop, the development of new classes of antibiotics has lagged far behind the urgent requirement for new drugs. This is in part because discovering safe and effective new antibiotics is scientifically challenging and because many major pharmaceutical companies withdrew from developing expensive new drugs likely to become rapidly obsolete through resistance. Consequently, novel antibacterial drugs with that do not succumb to conventional antibiotic resistance mechanisms, nor select for new forms of resistance, nor damage the host microflora, are desperately needed. The discovery of such drugs depends on a thorough understanding of the physiology and molecular biology of pathogenic bacteria and their strategies for colonizing host tissues and combatting host immune defences. These include the deployment of multiple virulence factors such as enzymes and toxins that cause host tissue damage and disease. Conventional antibiotics mostly act by killing bacteria and so exert enormous selective pressures leading to the emergence of resistant strains. If however, instead of killing bacteria, we simply prevent them deploying their virulence factors, infection should be attenuated with less pressure for resistance to emerge. Research on bacterial virulence factors and their control systems enables us to identify molecular target 'weak points' in bacteria so that methods for screening drug-like compounds active against such targets can be designed and new antibacterial drugs discovered. One promising target for anti-virulence agents is quorum sensing (QS). Although bacteria are single cell organisms, they can synchronize the activities of all the cells in a population through cell-to-cell communication. This is achieved through the production and sensing of signal molecules that inform the infecting bacteria that they are present in sufficient numerical strength to deploy their virulence factors and mount an attack. QS systems offer multiple molecular targets for anti-infective agents that include the production, export and response to QS signal molecules. In problematic multi-antibiotic resistant pathogens such as Staphylococcus aureus (including MRSA) and Clostridium difficile, virulence factors including many major exotoxins are controlled by the agr QS system that employs autoinducing peptide signal (AIP) molecules. In this research project we are seeking to understand in depth the way in which S. aureus produces and exports AIP signal molecules via two transmembrane proteins called AgrB and 1984 since these are key to QS and hence virulence. We propose to use a multidisciplinary approach combining microbiology with chemistry, structural biology to elucidate the functions and 3D structures of the key enzymes involved in AIP generation. We also plan to discover how AIPs are exported out of the bacterial cell and to develop new drug-like molecules that block AIP production generation in staphylococci. These will be tested for efficacy alone and in combination with conventional antibiotics in laboratory media and by using novel infection imaging tools that will provide information on when and where agr-dependent QS is switched on or off. The work will focus primarily on S. aureus but promising compounds will also be tested against enterococci, clostridia and listeria and other. other staphylococcal species.

多重抗生素耐药细菌的出现、快速传播和持续存在被世界卫生组织认为是全球对人类健康的三大威胁之一。抗菌素耐药性 (AMR) 甚至会威胁到简单感染和常见医疗干预措施（外科手术、牙科、产科）的治疗和结果，而这些措施直到最近还被认为是低风险的。在此背景下，新型抗生素的研发远远落后于新药的迫切需求。部分原因是发现安全有效的新抗生素在科学上具有挑战性，而且许多大型制药公司退出了昂贵的新药开发，这些新药可能会因耐药性而迅速过时。因此，迫切需要不会屈服于传统抗生素耐药机制、不会选择新形式的耐药性、也不损害宿主微生物群的新型抗菌药物。此类药物的发现取决于对病原菌生理学和分子生物学及其定植宿主组织和对抗宿主免疫防御的策略的透彻了解。其中包括使用多种毒力因子，例如导致宿主组织损伤和疾病的酶和毒素。传统抗生素主要通过杀死细菌来发挥作用，因此会施加巨大的选择压力，导致耐药菌株的出现。然而，如果我们不是杀死细菌，而是简单地阻止它们发挥毒力因子，那么感染就会减弱，而产生耐药性的压力就会更小。对细菌毒力因子及其控制系统的研究使我们能够识别细菌中的分子靶标“弱点”，从而可以设计筛选针对这些靶标具有活性的类药化合物的方法并发现新的抗菌药物。群体感应（QS）是抗毒剂的一个有前景的目标。尽管细菌是单细胞生物，但它们可以通过细胞间的通讯来同步群体中所有细胞的活动。这是通过产生和感知信号分子来实现的，这些信号分子通知感染细菌，它们的数量足够多，可以部署毒力因子并发起攻击。 QS 系统为抗感染药物提供多个分子靶点，包括 QS 信号分子的产生、输出和响应。在金黄色葡萄球菌（包括 MRSA）和艰难梭菌等有问题的多重抗生素耐药病原体中，包括许多主要外毒素在内的毒力因子由采用自诱导肽信号 (AIP) 分子的 agr QS 系统控制。在这个研究项目中，我们试图深入了解金黄色葡萄球菌通过称为 AgrB 和 1984 的两种跨膜蛋白产生和输出 AIP 信号分子的方式，因为它们是 QS 和毒力的关键。我们建议采用微生物学与化学、结构生物学相结合的多学科方法来阐明 AIP 生成中涉及的关键酶的功能和 3D 结构。我们还计划发现 AIP 如何从细菌细胞中输出，并开发新的药物样分子来阻止葡萄球菌中 AIP 的产生。这些药物将在实验室介质中单独进行功效测试，并与传统抗生素结合使用，并使用新型感染成像工具进行测试，这些工具将提供有关 agr 依赖性 QS 何时何地开启或关闭的信息。这项工作将主要集中在金黄色葡萄球菌上，但也将针对肠球菌、梭状芽胞杆菌和李斯特菌等对有前景的化合物进行测试。其他葡萄球菌种类。

项目成果

Detection of Agr-Type Autoinducing Peptides Produced by Staphylococcus aureus.

金黄色葡萄球菌产生的 Agr 型自诱导肽的检测。

• DOI: 10.1007/978-1-4939-7309-5_7
• 发表时间: 2024-09-14
• 期刊: Methods in molecular biology
• 作者: Ewan Murray;Paul Williams
• 通讯作者: Paul Williams

Gaussia Luciferase as a Reporter for Quorum Sensing in Staphylococcus aureus.

高斯荧光素酶作为金黄色葡萄球菌群体感应的报告者。

• DOI: http://dx.10.3390/s20154305
• 发表时间: 2020
• 期刊: Sensors (Basel, Switzerland)
• 作者: Blower I

Conformational analysis and interaction of the Staphylococcus aureus transmembrane peptidase AgrB with its AgrD propeptide substrate.

金黄色葡萄球菌跨膜肽酶 AgrB 与其 AgrD 前肽底物的构象分析和相互作用。

• DOI: http://dx.10.3389/fchem.2023.1113885
• 发表时间: 2023
• 期刊: Frontiers in chemistry
• 作者: Bardelang P

Interactions of polymyxin B with lipopolysaccharide-containing membranes.

多粘菌素 B 与含脂多糖膜的相互作用。

• DOI: http://dx.10.1039/d1fd00036e
• 发表时间: 2021
• 期刊: Faraday discussions
• 影响因子: 3.4
• 作者: Goode A

To Boil an Egg: Substrate Binding Affects Critical Stability in Thermal Unfolding of Proteins.

煮鸡蛋：底物结合影响蛋白质热解折叠的临界稳定性。

• DOI: http://dx.10.1021/acs.jpcb.7b10643
• 发表时间: 2018
• 期刊: The journal of physical chemistry. B
• 作者: Hussain R