A novel pathway altering OM permeability

改变 OM 渗透性的新途径

• 批准号: 10716575
• 负责人: Angela Marie Mitchell
• 金额: $ 7.19万
• 依托单位: TEXAS A&M UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-08 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10716575
• 关键词: Address; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Bacteria; Biological Assay; Biology; Cell Membrane Permeability; Cells; Centers for Disease Control and Prevention (U.S.); Charge; Chemicals; Clinical; DNA; DNA Damage; DNA Repair; DNA lesion; Data; Development; Disease; Environment; Escherichia coli; Escherichia coli K12; Exclusion; Exposure to; Future; Gene Expression; Genes; Genetic Transcription; Goals; Gram-Negative Bacteria; Hydrophobicity; Intestines; Laboratories; Lateral; Libraries; Life; Link; Lipopolysaccharides; Membrane; Mismatch Repair; Mutagenesis; Mutation; Nutrient; Osmotic Pressure; Pathway interactions; Permeability; Phospholipids; Physiological; Probability; Public Health; Replication Error; Resistance; Resistance development; Signal Pathway; Signal Transduction; Sodium Chloride; Stress; Temperature; Tensile Strength; Work; antimicrobial; bacterial genetics; bile salts; biological adaptation to stress; cell envelope; clinically relevant; cost; drug discovery; experience; fitness; high throughput screening; mutant; new therapeutic target; novel; physical insult; prevent; resistance mutation; resistant strain; response; small molecule; success; transcriptome sequencing; wound treatment

PROJECT SUMMARY The gram-negative outer membrane (OM) represents a strong permeability barrier that impedes the entry of many antibiotics. The majority of the species the US Centers for Disease Control and Prevention list as of “urgent” or “serious” concern for antibiotic resistance are gram-negative in part due to the impermeability of the OM. In recent years, it has become clear that the permeability of the OM can be altered by the physiological state of the cell. Specifically, clinically relevant stresses such as nutrient limitation can result in strengthening of the OM permeability barrier, further decreasing the entry of antibiotics. Elucidation of the pathways responsible for this strengthening will lead to new targets for the development of small molecules that can weaken the OM permeability barrier. The laboratory’s long-term goal is to understand the mechanisms that change the permeability of the OM during periods of clinically relevant stress. Specifically, this project aims to elucidate a novel link between loss of DNA mismatch repair (MMR) and alteration of OM permeability in Escherichia coli K12. MMR is a highly conserved DNA repair mechanism found throughout all domains of life. MMR mutants have been found in clinical antibiotic resistant strains and have been proposed to be an antecedent to the development of resistance mutations facilitated by an increased mutation rate. However, preliminary data demonstrate a second pathway where loss of MMR leads to resistance to a broad range of antibiotics through alteration of OM permeability. Thus, loss of MMR in a host environment would allow bacteria to survive antibiotics treatment longer, while also increasing the probability that a specific resistance mutation can develop due to the increased mutation rate. The SOS DNA damage stress response pathway is not necessary for strengthening the OM permeability barrier demonstrating that a novel pathway connects loss of MMR to OM permeability. The central hypothesis of this work is loss of MMR activates a novel pathway involving signal transduction and transcriptional changes that alter the permeability profile of the OM. This project will elucidate genes involved in this pathway by identifying transcriptional changes that result from pathway activation leading to altered OM permeability (Aim 1) and determining the genes that are necessary for the pathway to altered OM permeability (Aim 2). Completion of the aims will transform understanding of the link between DNA repair and OM permeability and has the potential to uncover new targets for drug discovery.

项目摘要 革兰氏阴性菌外膜（OM）是一个强大的渗透性屏障，阻止细菌进入。 许多抗生素。美国疾病控制和预防中心列出的大多数物种， 对抗生素耐药性的“紧急”或“严重”关注是革兰氏阴性的，部分原因是由于 OM。近年来，已经清楚的是，OM的渗透性可以通过生理学改变。 细胞的状态。具体来说，临床相关的压力，如营养限制，可导致加强 OM渗透屏障，进一步减少抗生素的进入。阐明相关途径 因为这种强化将为开发能够削弱OM的小分子带来新的目标 渗透屏障该实验室的长期目标是了解改变生物学特性的机制。 在临床相关应激期间OM的渗透性。 具体而言，该项目旨在阐明DNA错配修复（MMR）缺失与 大肠杆菌K12中OM渗透性的改变。MMR是一种高度保守的DNA修复机制， 在生活的各个领域。MMR突变体已在临床抗生素耐药菌株中发现， 被认为是耐药突变发展的先决条件，而耐药突变的发展是由耐药基因的增加所促进的。 突变率然而，初步数据表明，MMR的丧失导致耐药的第二种途径 通过改变OM的渗透性，使其与多种抗生素结合。因此，宿主环境中的MMR损失 这将使细菌在抗生素治疗中存活更长时间，同时也增加了特定细菌感染的可能性。 由于突变率的增加，可以产生耐药性突变。SOS DNA损伤应激反应 途径是不是必要的，以加强OM渗透屏障，表明一种新的途径， 将MMR损失与OM磁导率联系起来。 这项工作的中心假设是MMR的丧失激活了一种涉及信号转导的新途径， 转录变化改变OM的渗透性概况。这个项目将阐明基因参与 通过识别由导致OM改变的途径激活引起的转录变化来识别该途径 渗透性（目的1）和确定的基因是必要的途径，改变OM渗透性 (Aim 2）。这些目标的完成将改变对DNA修复和OM之间联系的理解 渗透性，并有可能发现新的药物发现的目标。