Uncovering the role of polyamines in bacterial survival and antibiotic resistance

揭示多胺在细菌存活和抗生素耐药性中的作用

• 批准号: RGPIN-2022-04239
• 负责人: ElHalfawy, Omar
• 金额: $ 2.26万
• 依托单位: University of Regina
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=748453
• 关键词: Uncovering; role; polyamines; bacterial; survival

Bacteria encounter many chemicals in their extracellular milieu. Conceivably, these chemicals collectively affect cellular responses influencing bacterial survival and antibiotic resistance. Such effects are typically undetected in standard in vitro assays, often overlooking critical virulence and antibiotic resistance phenotypes. A prominent class of such chemicals is polyamines being ubiquitous in the environment and overproduced by plant and animal cells during infection. High concentrations of polyamines kill bacteria. Yet, before reaching lethal levels, polyamines make bacteria either more resistant or susceptible to many antibiotics, thereby changing the efficacy of these drugs. The overall goal of my NSERC research program is to understand how polyamines interact with bacteria influencing their survival and adaptation under stress. The proposed research advances my earlier work that identified the role of polyamines in antibiotic resistance and harnesses high-throughput chemical genomics approaches to study bacterial responses at the whole-genome level. I hypothesize that bacteria use previously unrecognized mechanisms to withstand high polyamine concentrations. Further, I hypothesize that polyamines modulate the bacterial responses to antibiotics through interaction with specific cellular targets and that antibiotic exposure triggers regulatory cascades linking polyamine production to the antibiotic response. To address these hypotheses, I propose three parallel and complementary work packages to achieve three specific objectives of this discovery grant: 1. Study how model Gram-positive and Gram-negative bacteria tolerate high concentrations of polyamines. 2. Determine the mechanisms by which polyamines mediate altered responses to antibiotics. 3. Characterize the regulatory networks underpinning polyamine role in response to antibiotics. My lab will use a whole-genomic approach to interrogate thousands of mutants, each harboring single gene deletions, profiling their responses to polyamines and polyamine-antibiotic combos. We will also construct a reporter library to measure the expression of polyamine biosynthetic enzymes when exposed to antibiotics. We will use S. aureus and E. coli as representatives of Gram-positive polyamine non-producer and Gram-negative polyamine-producer bacteria, respectively. Through this systems approach, we will formulate new hypotheses that will allow us to undertake detailed analyses using conventional biochemical and molecular biology methods providing mechanistic insights into the bacterial responses to polyamines and antibiotic resistance. Together, my research program addresses a significant knowledge gap in understanding the importance of polyamines in bacterial survival and antibiotic resistance. The discoveries generated from this program will pave the way for future applications to fight superbugs and will have tangible benefits to the healthcare systems, agriculture, and the biotech sectors.

细菌在其细胞外环境中遇到许多化学物质。可以想象，这些化学物质集体影响了影响细菌存活和抗生素耐药性的细胞反应。这种影响通常在标准的体外测定中未发现，通常忽略了关键的毒力和抗生素耐药性表型。一类突出的化学物质是多胺在环境中无处不在，并且在感染过程中由动植物细胞过多生产。高浓度的多胺杀死细菌。然而，在达到致命水平之前，多胺使细菌更具耐药性或容易受到许多抗生素的影响，从而改变了这些药物的疗效。我的NSERC研究计划的总体目标是了解多胺如何与细菌相互作用，从而影响其在压力下的生存和适应性。拟议的研究推进了我较早的工作，该研究确定了多胺在抗生素耐药性中的作用，并利用了高通量化学基因组学方法来研究整个基因组水平的细菌反应。我假设细菌使用先前未认可的机制来承受高多胺浓度。此外，我假设多胺通过与特定细胞靶标的相互作用调节对抗生素的细菌反应，并且抗生素暴露触发了将多胺产生与抗生素反应联系起来的调节级联。为了解决这些假设，我提出了三个平行和互补的工作包，以实现这一发现赠款的三个特定目标：1。研究模型革兰氏阳性和革兰氏阴性细菌如何耐受高浓度的多胺。 2。确定多胺介导对抗生素反应改变的机制。 3。表征响应抗生素的多胺作用的调节网络。我的实验室将使用一种全基因组方法来询问数千个突变体，每个突变体都有单个基因缺失，分析了它们对多胺和多胺 - 抗生素组合的反应。我们还将构建一个记者文库，以测量暴露于抗生素时多胺生物合成酶的表达。我们将分别使用金黄色葡萄球菌和大肠杆菌作为革兰氏阳性多胺非生产剂和革兰氏阴性多胺产生细菌的代表。通过这种系统方法，我们将制定新的假设，使我们能够使用常规的生化和分子生物学方法进行详细的分析，从而为对多胺和抗生素耐药性提供机械洞察力。我的研究计划共同解决了了解多胺在细菌生存和抗生素耐药性中的重要性方面的重要知识差距。从该计划产生的发现将为将来的应用与超级细菌作斗争的道路铺平道路，并将为医疗保健系统，农业和生物技术领域带来切实的好处。