The role of cytochrome bd in uropathogenic Escherichia coli pathogenesis

细胞色素bd在尿路致病性大肠杆菌发病机制中的作用

• 批准号: 10231073
• 负责人: Connor James Beebout
• 金额: $ 4.89万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10231073
• 关键词: Affinity; Amino Acids; Anaerobic Bacteria; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Bacteria; Bacterial Infections; Bacterial Model; Binding; Biochemical; Biology; Bladder; Catheters; Cell Respiration; Chronic; Citric Acid Cycle; Clinical; Communicable Diseases; Communities; Complement; Complex; Consumption; Cytochromes; Data; Development; Diffusion; Drug Targeting; Environment; Enzymes; Exhibits; Extracellular Matrix; Health; Heterogeneity; Host Defense; Human; Hydroquinones; Hypoxia; Imaging Techniques; Immune; Immune system; Immunity; Impairment; Infection; Infective cystitis; Knowledge; Life Style; Metabolic; Metabolism; Microbial Biofilms; Molecular; Natural Immunity; Nitric Oxide; Nutrient; Operative Surgical Procedures; Oxidases; Oxygen; Pathogenesis; Patients; Penetrance; Penetration; Phagocytes; Phase; Physicians; Physiology; Play; Predisposition; Prevention; Production; Proliferating; Property; Research; Respiration; Respiratory physiology; Role; Scientist; Series; Surface; Testing; Tissues; Training; Translational Research; Up-Regulation; Urinary tract infection; Uropathogenic E. coli; Urothelial Cell; Virulence; Work; antibiotic resistant infections; antibiotic tolerance; aqueous; assault; bacterial community; bacterial genetics; bacterial metabolism; career; cytochrome c oxidase; defined contribution; experimental study; fundamental research; imaging study; in vivo; insight; mouse model; mutant; overexpression; oxidation; quinol oxidase; recurrent infection; respiratory; respiratory enzyme; stressor

PROJECT SUMMARY Biofilms are multicellular bacterial communities implicated in the majority of bacterial infections, and nearly all chronic bacterial infections. These communities are nearly impossible to eradicate by traditional chemotherapeutic approaches and represent a major threat to human health. Biofilm bacteria secrete an extracellular matrix (ECM) that limits the ability for phagocytes, complement, antibiotics, and other external stressors to interact with biofilm bacteria. Accordingly, biofilms are highly resistant to antibiotics and the immune system, often necessitating that patients with biofilm-associated infections receive long-term suppressive antibiotics or undergo surgery to remove infected tissues. In addition to inhibiting penetrance of antibiotics and immune defenses, the ECM limits diffusion of nutrients such as oxygen, which, in conjunction with the metabolic activity of resident bacteria, establishes oxygen gradients within biofilms that render the interior of biofilms hypoxic. Several studies have demonstrated that oxygen gradients play a critical role in the development of resilient biofilm communities, and that in biofilms oxygen availability is a central regulator of bacterial metabolism and expression of ECM components. Previous work in uropathogenic Escherichia coli (UPEC), the primary cause of urinary tract infections, has demonstrated that despite being a facultative anaerobe, UPEC relies on aerobic respiration during infection and to form biofilm communities. Through my thesis research, I have shown that UPEC heterogeneously expresses respiratory enzymes, and that these enzymes are expressed in discrete subpopulations. Despite this heterogeneity of expression, only expression of cytochrome bd, a high affinity quinol oxidase necessary for aerobic respiration under hypoxic conditions, is required for UPEC pathogenesis and biofilm formation. Loss of cytochrome bd, but not other quinol oxidases, disrupts biofilm development, alters ECM production, increases susceptibility to antibiotics, and impairs virulence in a murine model of infection. This proposal outlines a series of experiments which will define the role of cytochrome bd in urinary tract infection pathogenesis and the ability for UPEC to form biofilm communities capable of withstanding antibiotic therapy and immune assault. Completion of this proposal will identify bottlenecks that restricts colonization by cytochrome bd deficient UPEC, biochemically define the role of cytochrome bd in the intracellular phase of urinary tract infection, and define mechanisms by which cytochrome bd promotes the formation of antibiotic tolerant biofilms. These studies will yield fundamental insights into how adaptation of central metabolic processes allows bacteria to adapt to diverse host niches and establish resilient biofilm communities, while also investigating cytochrome bd as a potential drug target to aid in the prevention or eradication of biofilm-associated infection.

项目摘要 生物膜是与大多数细菌感染有关的多细胞细菌群落，几乎全部 慢性细菌感染。这些社区几乎不可能通过传统的 化学治疗方法并代表了对人类健康的主要威胁。生物膜细菌分泌 细胞外基质（ECM）限制了吞噬细胞，补体，抗生素和其他外部的能力 与生物膜细菌相互作用的压力源。因此，生物膜对抗生素具有高度耐药性， 免疫系统通常需要生物膜相关感染患者长期接受 抑制性抗生素或接受手术以去除感染组织。除了抑制 抗生素和免疫防御，ECM限制了氧气等养分的扩散 随着居民细菌的代谢活性，在生物膜内建立氧梯度 生物膜缺氧的内部。几项研究表明，氧梯度在 弹性生物膜群落的发展，在生物膜中，氧气的可用性是 ECM成分的细菌代谢和表达。先前在尿道疾病大肠杆菌中的工作 （UPEC）是尿路感染的主要原因，它表明，尽管是兼职 Anaerobe，UPEC依靠感染期间有氧呼吸并形成生物膜群落。通过我的 论文研究，我表明UPEC异质表达呼吸酶，并且这些酶 酶在离散亚群中表达。尽管表达的异质性，但仅表达 在低氧条件下需要有氧呼吸所必需的高亲和奎因氧化酶的细胞色素BD的IS UPEC发病机理和生物膜形成所必需的。细胞色素BD的丧失，但没有其他喹诺尔氧化酶， 破坏生物膜的开发，改变ECM的产生，增加对抗生素的敏感性，并损害 在鼠类感染模型中的毒力。该建议概述了一系列实验，这些实验将定义 细胞色素BD在尿路感染发病机理中的作用和UPEC形成生物膜的能力 能够承受抗生素疗法和免疫攻击的社区。该提议的完成将 识别限制细胞色素BD缺乏upec的瓶颈，从生化上定义角色 在尿路感染的细胞内相中的细胞色素BD，并定义了机制 细胞色素BD促进抗生素耐受生物膜的形成。这些研究将产生基本 了解中央代谢过程适应如何使细菌适应各种宿主壁ni和 建立弹性生物膜群落，同时还研究细胞色素BD作为潜在的药物靶标 在预防或根除生物膜相关感染中。