Bisbiguanide analogues as probes for assessing membrane barrier function in multidrug resistant Gram-negative bacteria.

双双胍类似物作为探针评估多重耐药革兰氏阴性细菌的膜屏障功能。

• 批准号: 2547268
• 金额: --
• 依托单位: King's College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2547268
• 关键词: Bisbiguanide; analogues; probes; assessing; membrane

Aim:The key aim of this project is to develop a number of bisbiguanide-based membrane active probes to investigate the barrier properties of the Gram-negative membrane. The overarching aim is to identify chemical features of small molecules that enable them to penetrate and accumulate inside Gram-negative bacteria.Remit:This project aligns with the BBSRC "Bioscience for Health" theme and addresses BBSRC priority "Combatting Antimicrobial Resistance" (specifically "underpinning the development of novel antimicrobials and alternatives to antimicrobials"). This project focuses on mechanistic understanding of "effects and interactions of drugs with cells", "understanding the mechanisms of drug resistance, prevention and combating drug resistance" and inlcludes "research that underpins the development of strategies to mitigate the effects of antimicrobial resistance", "technology development for replacing animal use in drug testing". As such the project is well aligned with BBSRC remit.Background, Rational and Importance:The discovery of new antibiotics effective against Gram-negative bacteria is a major challenge due to the permeability barrier of two-membrane cell envelope of Gram-negative bacteria and limited chemical diversity of compound libraries to probe this barrier. The expansion of the chemical space of antibacterial tool compounds and identification of compounds that can penetrate the Gram-negative membrane barrier is urgent to understand the chemical features of compounds that are able to overcome the Gram-negative membrane barrier. The industrial applicants have previously been involved in screening of the Prestwick Chemical Library, commissioned by ANTRUK, and identified a small limited number of compounds which either showed direct antimicrobial effects against MDR Gram-negative pathogens or which were able to synergise with specific antibiotics to potentiate their activity against resistant isolates (Hind et al 2019). Two related compounds, chlorhexidine and alexidine, showed high levels of potentiation against all of the strains tested. These bisbiguanides are well characterised antiseptic agents used in a wide range of clinical settings, but the scaffold has not been rigourously explored to understand whether derivatives have separable membrane permeabilising activity and antibacterial properites.Bisbiguanides offer an excellent chemical scaffold for probe development due to their ability to interact with Gram-negative membranes. We will use these probes to improve the understanding of the molecular basis for low-permeability barriers of the problematic Gram-negative pathogens and define the physicochemical properties that enable uptake of various compounds into bacterial cells using probes synthesied as part of this PhD project. Coupled with other methods for studying membrane perturbation, including whole genome sequencing of ESKAPE mutants generated by serial passage (where resistance emerges), and strain libraries with known modifications in membrane structure/function, will provide a powerful new basis for understanding uptake, and the ability of compounds to penetrate or disrupt bacterial membranes.The study will also look at the properties of membrane active compounds like bisbiguanides which restrict their potential use for systemic therapy; specifically their eukaryotic cell toxicity. The project will extend the studies exploring interaction of biguanides with the bacterial membrane to include an assessment of their activity in mammalian membranes, to further extend our understanding of their structure activity relationship.

目的：本项目的主要目的是开发一系列基于双胍的膜活性探针，用于研究革兰氏阴性菌膜的屏障特性。Remit：该项目与BBSRC“生物科学促进健康”的主题相一致，并解决了BBSRC的优先事项“对抗抗菌素耐药性”（特别是“支持新型抗菌素和抗菌素替代品的开发”）。该项目重点关注“药物与细胞的作用和相互作用”的机制理解，“了解耐药性、预防和对抗耐药性的机制”，包括“支持制定减轻抗菌药物耐药性影响的策略的研究”，“在药物测试中取代动物使用的技术开发”。因此，该项目与BBSRC的职权范围非常一致。背景、合理性和重要性：由于革兰氏阴性菌的双膜细胞包膜的渗透性屏障和化合物文库的有限化学多样性，发现有效对抗革兰氏阴性菌的新抗生素是一个重大挑战。拓展抗菌工具化合物的化学空间和鉴定能够穿透革兰氏阴性菌膜屏障的化合物是了解能够克服革兰氏阴性菌膜屏障的化合物的化学特征的迫切需要。工业申请人之前参与了由ANTRUK委托的Prestwick化学品库的筛选，并确定了少量有限数量的化合物，这些化合物对MDR革兰氏阴性病原体显示出直接的抗菌作用，或者能够与特定抗生素协同作用，以增强其对耐药分离株的活性（Hind et al 2019）。两种相关化合物，氯己定和阿来西定，对所有测试菌株显示出高水平的增强作用。这些bisbiguanides是很好地表征抗菌剂在广泛的临床设置中使用，但支架还没有被严格探索，以了解衍生物是否具有可分离的膜透化活性和抗菌properites.Bisbiguanides探针开发提供了一个很好的化学支架，由于其与革兰氏阴性菌膜相互作用的能力。我们将使用这些探针来提高对有问题的革兰氏阴性病原体的低渗透性屏障的分子基础的理解，并定义物理化学性质，使各种化合物能够使用作为该博士项目的一部分合成的探针吸收到细菌细胞中。结合其他研究膜扰动的方法，包括连续传代产生的ESKAPE突变体的全基因组测序（出现耐药性的地方），以及具有已知膜结构/功能修饰的菌株文库，将为理解摄取提供强有力的新基础，以及化合物穿透或破坏细菌膜的能力。该研究还将研究膜活性化合物的特性，如限制了它们用于全身治疗的潜在用途的双双胍;特别是它们的真核细胞毒性。该项目将扩展探索双胍与细菌膜相互作用的研究，包括评估其在哺乳动物膜中的活性，以进一步扩展我们对其结构活性关系的理解。