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; 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 革兰氏阴性外膜（OM）代表强烈的渗透性屏障，阻碍了进入 许多抗生素。美国疾病控制和预防中心的大多数物种截至 对抗生素抗性的“紧急”或“严重”关注的部分是革兰氏阴性的，部分原因是 om。近年来，很明显，OM的渗透性可以通过生理学改变 细胞状态。具体而言，临床上相关的应力（例如营养限制）可能会加强 OM渗透性屏障进一步降低了抗生素的进入。阐明负责的途径 为了加强这种加强，将导致新的靶标，以发展可以削弱OM的小分子 渗透性障碍。实验室的长期目标是了解改变的机制 OM在临床相关压力期间的渗透性。 具体而言，该项目旨在阐明DNA不匹配修复（MMR）和 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 通过生活的所有领域。 MMR突变体已在临床抗生素抗性菌株中发现，并具有 我们被认为是通过增加而制备的抗性突变发展的前提 突变率。但是，初步数据证明了第二个途径，其中MMR损失导致阻力 通过改变OM渗透性，达到广泛的抗生素。那是在主机环境中MMR的损失 将使细菌能够生存更长的抗生素治疗，同时也增加了特定的可能性 由于突变率的增加，耐药突变会发展。 SOS DNA损伤应力反应 途径对于增强OM渗透性屏障并不是必需的，证明了新的途径 将MMR的损失连接到OM渗透性。 这项工作的中心假设是MMR的丧失激活了一种新的途径，涉及信号转导和 转录变化改变了OM的渗透率。该项目将阐明涉及的基因 通过识别由途径激活导致的转录变化，导致OM改变的转录变化 渗透性（AIM 1）并确定改变OM渗透率所必需的基因 （目标2）。目标的完成将改变对DNA修复与OM之间联系的理解 渗透性，并有可能发现新的药物发现靶标。