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.

项目概要 革兰氏阴性外膜 (OM) 代表强大的渗透性屏障，阻止细菌进入 美国疾病控制和预防中心列出的大多数抗生素。 对抗生素耐药性的“紧急”或“严重”关注是革兰氏阴性，部分原因是抗生素耐药性的不渗透性 近年来，人们已经清楚 OM 的渗透性可以通过生理改变来改变。 具体来说，临床相关的压力（例如营养限制）可能会导致细胞的强化。 OM 渗透屏障，进一步减少抗生素的进入。 因为这种加强将导致开发可以削弱 OM 的小分子的新目标 实验室的长期目标是了解改变渗透性屏障的机制。 在临床相关应激期间 OM 的渗透性。 具体来说，该项目旨在阐明 DNA 错配修复 (MMR) 丢失与 大肠杆菌 K12 中 OM 通透性的改变是一种高度保守的 DNA 修复机制。 MMR 突变体已在临床抗生素耐药菌株中发现并遍及生命的各个领域。 被认为是抗性突变发展的先决条件，而抗性突变的增加则促进了抗性突变的发展。 然而，初步数据表明，MMR 丧失会导致耐药性。 通过改变 OM 渗透性，从而导致宿主环境中 MMR 的丧失。 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的可能性 由于 SOS DNA 损伤应激反应的突变率增加，可能会产生抗性突变。 途径对于加强 OM 渗透屏障来说不是必需的，这表明新的途径 将 MMR 损失与 OM 渗透性联系起来。 这项工作的中心假设是 MMR 的丧失会激活一条涉及信号转导和 改变 OM 渗透性的转录变化该项目将阐明参与其中的基因。 通过识别导致 OM 的通路激活所导致的转录变化来实现该通路 渗透性（目标 1）并确定改变 OM 渗透性途径所需的基因 （目标 2）。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药物发现的新靶点。