Exploring susceptibility of L-form bacteria to antimicrobial peptides

探索 L 型细菌对抗菌肽的敏感性

• 批准号: 2884856
• 金额: --
• 依托单位: Newcastle University
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2884856
• 关键词: Exploring; susceptibility; form; bacteria; antimicrobial

BACKGROUND Antimicrobial resistance (AMR) is considered by the World Health Organization as one of the top 10 global public health threats. L-form switching is a mechanism, that allows bacteria (including important pathogens such as Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) or Pseudomonas spp.) to temporarily lose their cell wall. L-form bacteria are, thus, completely resistant to antibiotics, which target cell wall, such as penicillins , and are implicated in recurrence of many infectious diseases including urinary tract infections (UTIs), sepsis or foodborne infections. While tollerant to cell wall-targeting agents, L-forms should retain susceptibility to other types on antibiotics, for example those targeting membranes. OBJECTIVES AND NOVELTYAntimicrobial peptides (AMPs) are naturally occurring small peptides, which are part of the immune system of various organisms, including humans. These peptides most commonly target pathogen membranes, and AMPs such as nisin were shown to be effective against L-forms in vitro. In this PhD project, we will investigate the susceptibility of E. coli and S. aureus L-forms to various antimicrobial peptides in comparison to their walled counterparts. Using cell culture infection models (including cell lines and organoids) we will investigate for the first time if antimicrobial peptides can be used to eliminate L-form bacteria in the context of host tissue, therefore potentially contributing to prevention of recurrent infections. TIMELINESSAMR contributes to ~1.3 million deaths per year globally, with this number estimated to raise to 10 million by 2050, alongside a cumulative cost of $100 trillion, if no action is taken. This work will contribute to a better understanding of mechanisms of antibiotic evasion, more efficient use of the existing, and potential development of new treatments against bacterial infections. EXPERIMENTAL APPROACHEffectiveness of various AMPs (including cathelicidins, defensins, cecropin or synthetic ones) against E. coli and S. aureus L-forms will be tested using killing assays and high-end microscopy. We will systematically test if combining cell wall-targeting antibiotics with antimicrobial peptides might constitute a more effective treatment than each of the agents used alone, and precisely what proportion of each of the agents is most effective. We will use cell lines such as RAW 264.7, THP-1 macrophages and intestinal murine organoids combined with advanced fluorescence microscopy to test the effectiveness of AMPs against L-forms in a context of a tissue.The aim of this DTP is to add value by building synergies, developing new collaborations, and opening up new areas of research. How does this project add value, over and above what could be achieved with a standard studentship? (Maximum 100 words) This research project is a new collaboration between two Newcastle University based research groups. The primary supervisor Katarzyna Mickiewicz focuses on the role of L-form bacteria in disease and the secondary supervisor Henrik Strahl von Schulten on the mode of action of cell envelope targeting antibiotics. These are two complementary areas of expertise, which will accelerate the project and provide optimal training opportunities for the student to deliver on the project, which would not be possible for only one of these supervisors to achieve. 40% contribution from the senior second supervisor who will provide mentorship as well as the expertise, will be invaluable to the junior primary supervisor (60% contribution). Publications

背景抗菌素耐药性（AMR）被世界卫生组织（WHO）认为是全球十大公共卫生威胁之一。L型转换是一种机制，它允许细菌（包括重要的病原体，如大肠杆菌（E。coli）、金黄色葡萄球菌（S.金黄色）或假单胞菌属暂时失去细胞壁。因此，L-型细菌对靶向细胞壁的抗生素如青霉素具有完全抗性，并与许多感染性疾病的复发有关，包括尿路感染（UTIs）、脓毒症或食源性感染。虽然L型对靶向细胞壁的药物是耐受的，但L型应该保留对其他类型抗生素的敏感性，例如靶向膜的抗生素。目的和新颖性抗菌肽（AMP）是天然存在的小肽，其是包括人类在内的各种生物体免疫系统的部分。这些肽最常靶向病原体膜，并且AMP如乳链菌肽显示出在体外对L-型有效。在这个博士项目中，我们将研究E. coli和革兰氏阳性菌S.金黄色葡萄球菌L-型对各种抗微生物肽的抗性。使用细胞培养感染模型（包括细胞系和类器官），我们将首次研究抗微生物肽是否可用于消除宿主组织中的L型细菌，从而可能有助于预防复发性感染。如果不采取行动，TIMELINESSAMR每年在全球造成约130万人死亡，到2050年，这一数字估计将上升到1000万人，累计成本将达到100万亿美元。这一研究将有助于更好地理解抗生素逃避机制，更有效地利用现有的，并可能开发新的治疗细菌感染。实验方法各种AMP（包括cathelicidins、defensins、cecropin或合成的AMP）对E. coli和革兰氏阳性菌S.将使用杀灭试验和高端显微镜检查对金黄色葡萄球菌L型进行检测。我们将系统地测试靶向细胞壁的抗生素与抗微生物肽的组合是否可能构成比单独使用每种药物更有效的治疗，以及每种药物的精确比例是最有效的。我们将使用RAW 264.7、THP-1巨噬细胞和小鼠肠道类器官等细胞系，结合先进的荧光显微镜技术，在组织环境中测试AMP对L型的有效性。该DTP的目的是通过建立协同效应、开展新的合作和开辟新的研究领域来增加价值。这个项目如何增加价值，超过什么可以实现的标准学生？（最多100字）本研究项目是纽卡斯尔大学两个研究小组的新合作项目。主要负责人Katarzyna Mickiewicz专注于L型细菌在疾病中的作用，次要负责人Henrik Strahl von Schulten专注于细胞膜靶向抗生素的作用模式。这是两个互补的专业领域，将加快项目的进度，并为学生提供最佳的培训机会，以完成项目，而这是其中一个主管无法完成的。高级第二主管将提供指导和专业知识，其贡献率为40%，这对初级主要主管（贡献率为60%）是非常宝贵的。出版物