Experimental human infection with isogenic mutants of Neisseria gonorrhoeae

淋病奈瑟菌同基因突变体的实验性人类感染

• 批准号: 8925976
• 负责人: MARCIA METZGAR HOBBS
• 金额: $ 70.12万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-15 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8925976
• 关键词: Affect; Amendment; Animal Model; Antibiotic Resistance; Antibiotics; Attenuated; Award; Case Study; Cells; Centers for Disease Control and Prevention (U.S.); Clinical Trials; Development; Drug Targeting; Employee Strikes; Enzymes; Future; GC gene; Gene Expression; Generations; Goals; Gonococcal urethritis; Gonorrhea; HIV; Hand; Health; Host Defense; Human; Immune; Immune response; Immunity; In Vitro; Infection; Inflammation; Inflammatory; Lipid A; Lytic; Measures; Mediating; Mediator of activation protein; Membrane; Modality; Modeling; Molecular; Mus; Mutation; Nature; Neisseria gonorrhoeae; North Carolina; Outcome; Output; Pathogenesis; Peptidoglycan; Protocols documentation; Public Health; Pump; Pyuria; Qualifying; Reaction; Recovery; Relative (related person); Reporting; Reproductive Health; Research; Resistance; Severities; Sexually Transmitted Diseases; Signal Transduction; Signs and Symptoms; Structure; Surface; System; Testing; Therapeutic; Time; Transferase; U-Series Cooperative Agreements; Universities; Urethra; Urethritis; Vaccines; Work; adaptive immunity; antimicrobial; bacterial resistance; cell envelope; cytokine; derepression; drug development; efflux pump; fitness; genital infection; high risk; in vivo; indexing; killings; male; men; mouse model; mutant; novel; novel therapeutics; novel vaccines; pathogen; peptidoglycan monomer; phosphoethanolamine; programs; public health relevance; transmission process; volunteer

 DESCRIPTION (provided by applicant): Gonorrhea remains a global public health problem with over 106 million cases estimated by WHO in 2008 and over 334,000 cases reported to the US CDC in 2012, and rates are on the rise. With increasing Neisseria gonorrhoeae (GC) antibiotic resistance and no new antimicrobial therapies in the pipeline, the possibility of incurable gonorrhea is uncomfortably real. The potential adverse health consequences of untreatable GC and attendant increases in HIV transmission are alarming and highlight the urgent need for new therapeutic and vaccine targets. Our long term goals are to understand the molecular mechanisms of GC pathogenesis and identify bacterial structures required for infection with the aim of discovering potential novel targets for GC vaccines and/or treatments. In nature, GC only infects humans, which limits the extent to which results in animal models are clinically translatable. Accordingly, we propose a clinical trial with the immediate goals of 1) determining the requirement for several GC cell envelope structures in male urethral infection and 2) characterizing human immune responses to mutants lacking these structures. The expected outcome of the trial is the identification of one or more GC envelope structures required for human infection, which will validate these structures as potential novel targets for GC vaccines or treatments. The assembled research team manages the experimental human gonococcal infection program at the University of North Carolina, which is currently the only one of its kind in the world, providing a unique opportunity to study GC factors and host responses in human infection under controlled conditions. Experimental urethral infection of male volunteers is safe, and wild-type GC elicit signs and symptoms of natural gonorrhea. The proposed trial focuses on several surface structures that mediate GC resistance to human innate immune responses. We hypothesize that experimental male urethral infection with GC strains containing mutations that alter or eliminate these structures will show reduced mutant infectivity, decreased inflammation or increased GC mutant clearance compared to wild-type GC. We will use noncompetitive infections to measure GC survival and host immune responses in addition to changes in GC gene expression. We propose studies of three GC envelope structures that we have shown mediate resistance to human innate immune cells and human-derived antimicrobial compounds in the lab and in a mouse model. Aim 1 focuses on mutations affecting the GC MtrCDE efflux pump, which exports host antimicrobial compounds and is important for GC infection in human cell systems and in murine genital infection. Aim 2 focuses on mutations that alter the structure of lipid A, which is important for intracellular GC survival in vitro, and influences GC survival in mice. Finally, Aim 3 focuses on mutations in GC enzymes that cause release of peptidoglycan subunits that modulate innate immune responses in human cell systems and in mice. The GC envelope structures that we aim to test in the trial have not been well-studied in human infection, and they represent novel potential therapeutic and/or vaccine targets.

 描述（由申请人提供）：淋病仍然是一个全球性公共卫生问题，2008 年世界卫生组织估计有超过 1.06 亿例病例，2012 年向美国疾病预防控制中心报告了超过 334,000 例病例，而且发病率正在上升。随着淋病奈瑟菌 (GC) 抗生素耐药性的增加，并且没有新的抗菌疗法正在研发中，淋病无法治愈的可能性是真实存在的，这令人不安。无法治疗的胃癌和随之而来的艾滋病毒传播增加所带来的潜在不良健康后果令人震惊，并凸显了对新治疗和疫苗目标的迫切需要。我们的长期目标是了解GC发病机制的分子机制并确定感染所需的细菌结构，旨在发现GC疫苗和/或治疗的潜在新靶点。在自然界中，GC 仅感染人类，这限制了动物模型结果的临床可转化程度。因此，我们提出一项临床试验，其近期目标是 1) 确定男性尿道感染中对几种 GC 细胞包膜结构的需求，2) 表征人类对缺乏这些结构的突变体的免疫反应。该试验的预期结果是鉴定人类感染所需的一个或多个GC包膜结构，这将验证这些结构作为GC疫苗或治疗的潜在新靶标。该研究团队在北卡罗来纳大学负责管理人类淋球菌感染实验项目，该项目是目前世界上唯一的此类项目，为在受控条件下研究人类感染中的 GC 因素和宿主反应提供了独特的机会。男性志愿者的实验性尿道感染是安全的，野生型 GC 会引发自然淋病的体征和症状。拟议的试验重点关注介导 GC 对人类先天免疫反应的抵抗的几种表面结构。我们假设，与野生型GC相比，含有改变或消除这些结构的突变的GC菌株的实验性男性尿道感染将表现出突变体感染性降低、炎症减少或GC突变体清除增加。除了 GC 基因表达的变化之外，我们还将使用非竞争性感染来测量 GC 存活率和宿主免疫反应。我们提出了对三种 GC 包膜结构的研究，我们已经在实验室和小鼠模型中证明它们介导了对人类先天免疫细胞和人源抗菌化合物的耐药性。目标 1 重点关注影响 GC MtrCDE 外排泵的突变，该泵输出宿主抗菌化合物，对于人类细胞系统和小鼠生殖器感染中的 GC 感染很重要。目标 2 重点关注改变脂质 A 结构的突变，这对于细胞内 GC 体外存活很重要，并影响小鼠的 GC 存活。最后，目标 3 重点关注 GC 酶的突变，这些突变会导致肽聚糖亚基的释放，从而调节人类细胞系统和小鼠的先天免疫反应。我们打算在试验中测试的 GC 包膜结构尚未在人类感染中得到充分研究，它们代表了新的潜在治疗和/或疫苗靶点。