Consequences of vaginal microbiota on IFNγ-mediated clearance of Chlamydia trachomatis

阴道微生物群对 IFNγ 介导的沙眼衣原体清除的影响

• 批准号: 9240286
• 负责人: Ashok A Aiyar
• 金额: $ 60.81万
• 依托单位: LSU HEALTH SCIENCES CENTER
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-08 至 2021-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9240286
• 关键词: Address; Affect; African American; Anabolism; Anaerobic Bacteria; Animals; Bacteria; Bacterial Vaginosis; Biological Factors; Biological Models; Cell model; Cells; Cervical; Chlamydia Infections; Chlamydia trachomatis; Chronic; Classification; Clinic; Clinical; Clinical Data; Coculture Techniques; DNA; Data; Ectopic Pregnancy; Endocervix; Enrollment; Environment; Enzymes; Epithelial Cells; Essential Amino Acids; Failure; Female; Fertility; Gene Expression; Gene Expression Profile; Generations; Genes; Genital system; Genitourinary system; Growth; Health; Human; Immune response; Immunity; Immunologics; In Vitro; Indoles; Infection; Infertility; Interferon Type II; Interferons; Intervention; Knowledge; Light; Longitudinal Studies; Mediating; Methods; Modeling; Molecular; Natural History; Neonatal; Outcome; Pathway interactions; Patients; Pelvic Inflammatory Disease; Pharmacology; Physiological; Population; Prevalence; Prevotella; Public Health; Publishing; RNA; Recombinant DNA; Reporting; Reproductive Health; Resolution; Role; Sampling; Sexually Transmitted Diseases; Site; Social Welfare; Testing; Therapeutic; Tryptophan; Tryptophan 2,3 Dioxygenase; Tryptophan Synthase; Tryptophanase; Tube; Vaccines; Vagina; Visit; Woman; clinical effect; co-infection; cohort; cytokine; design; high risk; immune clearance; improved; in vitro Model; in vivo; inhibitor/antagonist; member; microbiome; microbiota; novel; prevent; protective effect; reproductive; sexually active; small molecule; small molecule inhibitor; translational study; vaginal microbiome

Chlamydia trachomatis (CT) infections are a major public health concern as they can adversely affect female fertility and neonatal health. While natural history studies indicate that some women spontaneously clear their infection, the physiological conditions that permit spontaneous clearance of CT remain elusive. Understand the latter is key to developing an effective vaccine that to prevent CT infection and its devastating consequences. In vitro and in vivo studies indicate that interferon gamma (IFNγ) is the primary protective cytokine against CT. IFNγ induces the host enzyme indoleamine 2,3-dioxygenase (IDO1) that degrades tryptophan, an essential amino acid for CT, which cannot synthesize tryptophan de novo. All clinical genital CT isolates have evolved a mechanism to evade the effect of IFNγ, specifically they can express a functional tryptophan synthase that salvages exogenously provided indole to generate tryptophan within the intracellular chlamydial inclusion where it is impervious to IDO1. While neither CT, nor human cells, synthesize indole, some members of the vaginal microbiome that increase greatly in number and proportion during bacterial vaginosis (BV), can do so. Thus, we hypothesize that the composition of the vaginal microbiome, and its capacity to provide indole, modulates the efficacy of IFNγ-dependent host immunity against CT. This hypothesis is supported by our existing clinical data; although all women who spontaneously cleared CT infection had high endocervical IFNγ levels, so did ~40% of women who failed to clear infection. We propose to rigorously test this hypothesis using a cohort of high-risk African-American women attending our STD clinic in New Orleans. The cohort will be stratified into groups that spontaneously clear CT infections (~28% in our cohort) or fail to clear CT infection between enrollment and return-for-treatment visits. By focusing on women who spontaneously clear infection, and the ~40% of non- clearing women who meet the threshold endocervical IFNγ levels observed in clearers, we will investigate the following objectives: 1) Determine the infection micromilieu (tryptophan/indole/IFNγ/CT load & gene expression profile) correlates of clearance; 2) Determine differences in the prevalent vaginal microbiome, and its indole- generation capacity, between clearers and non-clearers; and 3) Using a novel endocervical epithelial cell model, directly test the capacity of indole-producing microbiome members to limit IFNγ-mediated CT clearance, and evaluate the efficacy of known small molecule indole biosynthesis inhibitors to augment IFNγ-mediated CT clearance during co-infections. The outcomes from the proposed studies will provide essential information needed to design novel immunological and pharmacological approaches that improve clinical outcomes for CT- infected patients. Modeling the mechanisms used during spontaneous clearance will define the effects of co- infection on the efficacy of the host response to CT-infection. This will significantly improve patient health and welfare in light of the tremendous human and financial toll that is imposed by genital CT infections.

沙眼衣原体 (CT) 感染是一个主要的公共卫生问题，因为它们会对 女性生育力和新生儿健康。虽然自然历史研究表明，一些女性会自发地清除 感染后，允许 CT 自发清除的生理条件仍然难以捉摸。理解 后者是开发有效疫苗来预防 CT 感染及其破坏性后果的关键。 体外和体内研究表明，干扰素 γ (IFNγ) 是针对 CT 的主要保护性细胞因子。 IFNγ 诱导宿主酶吲哚胺 2,3-双加氧酶 (IDO1) 降解色氨酸，色氨酸是人体必需的物质。 用于 CT 的氨基酸，不能从头合成色氨酸。所有临床生殖器 CT 分离株均已进化出 逃避 IFNγ 作用的机制，特别是它们可以表达功能性色氨酸合酶， 回收外源提供的吲哚，在细胞内衣原体包涵体中产生色氨酸，其中 它不受 IDO1 影响。虽然 CT 和人类细胞都不合成吲哚，但阴道细胞的某些成员 在细菌性阴道病（BV）期间，微生物群的数量和比例大幅增加，可以做到这一点。因此，我们 假设阴道微生物组的组成及其提供吲哚的能力调节 IFNγ依赖性宿主免疫对CT的功效。这一假设得到了我们现有临床数据的支持； 尽管所有自发清除 CT 感染的女性都具有较高的宫颈内 IFNγ 水平，但约 40% 的女性也有较高的宫颈内 IFNγ 水平。 未能清除感染的女性。我们建议使用一组高风险人群严格检验这一假设 到我们位于新奥尔良的性病诊所就诊的非裔美国妇女。该队列将被分为以下几组： 自发清除 CT 感染（在我们的队列中约 28%）或在入组和入组之间未能清除 CT 感染 返回治疗就诊。通过关注自发清除感染的女性，以及约 40% 的非感染者 对于达到在透明手术中观察到的宫颈内 IFNγ 水平阈值的女性，我们将调查 以下目标： 1) 确定感染微环境（色氨酸/吲哚/IFNγ/CT 负载和基因表达） 轮廓）间隙的相关性； 2) 确定常见阴道微生物组及其吲哚-的差异 清算者和非清算者之间的发电能力； 3) 使用新型宫颈内膜上皮细胞模型， 直接测试产生吲哚的微生物组成员限制 IFNγ 介导的 CT 清除的能力，以及 评估已知小分子吲哚生物合成抑制剂增强 IFNγ 介导的 CT 的功效 合并感染期间的清除。拟议研究的结果将提供重要信息 需要设计新的免疫学和药理学方法来改善 CT 的临床结果 感染的患者。对自发清除过程中使用的机制进行建模将定义共同作用的影响 感染对宿主对 CT 感染反应的功效的影响。这将显着改善患者的健康状况 鉴于生殖器 CT 感染造成的巨大人力和经济损失。