How E. coli Acid Response Mechanisms Breach Colonization Resistance in the Vagina

大肠杆菌酸反应机制如何突破阴道定植抗性

• 批准号: 10657442
• 负责人: Maria Hadjifrangiskou
• 金额: $ 55.51万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10657442
• 关键词: Acids; Bacteria; Bladder; Cervix Uteri; Data; Deaminase; Deamination; Environment; Epithelial Cells; Escherichia coli; Escherichia coli Infections; Genitourinary system; Gnotobiotic; Gravid; Horns; Human; In Vitro; Individual; Infection; Infection prevention; Intestines; Knowledge; Lactic acid; Lactobacillus; Lactobacillus delbrueckii; Life Style; Location; Maps; Measures; Modeling; Mus; Nutrient availability; Output; Pathogenesis; Pathway interactions; Predisposition; Pregnancy; Prevention; Probiotics; Production; Prophylactic treatment; Reaction; Regulation; Reporting; Resistance; Role; Sampling; Serine; Signal Transduction; System; Testing; Time; Toxin; Urinary tract; Urinary tract infection; Uropathogenic E. coli; Uterus; Vagina; Woman; acid stress; colonization resistance; combat; enteric infection; fitness; in vitro Model; in vivo; in vivo evaluation; member; microbiota; mutant; novel; pathogen; pathogenic Escherichia coli; pathogenic bacteria; prevent; prophylactic; protective effect; resistance mechanism; response; stillbirth; tissue culture; urogenital tract; vaginal microbiota

SUMMARY This proposal will test the over-arching hypothesis that extra-intestinal pathogenic Escherichia coli (ExPEC) overcomes inhibition by urogenital Lactobacilli via sequential activation of inter-connected acid resistance (AR) mechanisms. We further postulate that transient internalization of ExPEC into vaginal epithelial cells increases fitness by enhancing induction of acid resistance and other mechanisms of persistence that enable bacteria to gain access and survive in otherwise harsh host environments. The hypothesis to be tested has been formulated based on the following strong preliminary data: (1) We discovered a novel AR mechanism in ExPEC that is controlled via a non-canonical signaling system, BtsS-YpdB and it uses L-serine deamination to neutralize bacterial cytosolic pH. We call this new AR mechanism, AR6. (2) BtsS-YpdB signaling is induced during infection and in response to several Lactobacillus species. (3) Deletion of btsS-ypdB significantly decreases ExPEC acid tolerance and vaginal colonization. (4) Strains lacking L-serine deaminases, or BtsS- YpdB differentially react to the inhibitory actions of representative urogenital L. gasseri and L. delbrueckii isolates. (5) Deletion of btsS-ypdB alters the induction and function of the known acid-sensing system EvgSA that controls the most prominent, known AR mechanism, AR2. We will test these hypotheses using the most prevalent ExPEC pathotype, uropathogenic E. coli. Uropathogenic E. coli is the main cause of urinary tract infections (UTIs), an infection that disproportionately afflicts women. Similarly, ExPEC strains are the leading cause of infection-related stillbirths. Despite the dominant paradigm that the low pH of vagina is protective against pathogens, we and others have shown that colonization of the vagina by ExPEC can serve as a nidus for infection of the urinary tract, the cervix, uterine horns and the gravid uterus. Vaginal colonization is therefore a key step in pathogenesis. While several acid resistance (AR) mechanisms have been identified that are active in the gut, the relative contribution of each AR mechanism during ExPEC infection remains undefined. With our aims, we will: Interrogate the significance of transient bacterial expansion in the host as a priming niche for the amplification of acid resistance and other persistence mechanisms (Aim 1). We will evaluate the individual and combined contributions of AR mechanisms to the colonization potential of ExPEC in the vagina, bladder and gut and will elucidate the connection of the novel AR6 pathway we discovered to the induction and function of AR2 (Aim 2). Finally, building on exciting preliminary data we will investigate the potential of urogenital Lactobacilli strains in their ability to override ExPEC acid resistance, aiming to identify effective probiotic strategies to prevent ExPEC reservoir formation in the vagina (Aim 3). Completion these aims will uncover how ExPEC leverage their multiple AR systems to transit the host and evade elimination and will inform our efforts towards developing effective probiotic strategies to prevent, vaginal colonization and combat genitourinary tract infections.

概括 该提案将检验以下一个超大的假设，即肠外致病性大肠杆菌 （Expec）通过连接酸的顺序激活泌尿生殖器乳酸杆菌的抑制作用 电阻（AR）机制。我们进一步假设将excec的瞬时内在化成阴道上皮 细胞通过增强抗酸的抗性和其他持久机制来提高适应性 使细菌能够进入并在其他苛刻的宿主环境中生存。要检验的假设 已经根据以下强初步数据制定了：（1）我们发现了一种新型的AR机制 在通过非典型信号系统控制的Expec中，BTSS-ippDB，并使用L serine Deamination 中和细菌胞质pH。我们称这种新的AR机制AR6。 （2）诱导BTSS-ippDB信号传导 在感染期间和对几种乳杆菌的响应。 （3）删除BTSS-ippDB 降低了酸耐受性和阴道定植。 （4）缺乏L丝氨酸脱氨酶或BTSS-的菌株 YPDB对代表性的泌尿生殖器L. gasseri和L. delbrueckii的抑制作用差异反应 分离物。 （5）删除BTSS-ippDB改变了已知的酸敏感系统EVGSA的诱导和功能 控制最突出的，已知的AR机制AR2。我们将使用最多的假设来检验这些假设 普遍的Expec病理类型，尿路发育大肠杆菌。肝病大肠杆菌是尿路的主要原因 感染（UTI），这种感染不成比例地困扰着女性。同样，expec菌株是领先的 与感染相关的死亡原因。尽管具有主要范式，即阴道的低pH值保护 病原体，我们和其他人已经表明，Expec对阴道的定殖可以作为感染的Nidus 尿路，子宫颈，子宫角和妊娠子宫。因此，阴道定植是关键步骤 在发病机理中。虽然已经确定了在肠道中活跃的几种抗酸性（AR）机制 Excec感染期间每种AR机制的相对贡献仍然不确定。以我们的目标，我们 意愿：审问宿主中短暂细菌膨胀的重要性 酸耐药性和其他持久性机制的扩增（AIM 1）。我们将评估个人， AR机制对在阴道，膀胱和肠道中的定殖潜力的合并贡献 并将阐明我们发现的新型AR6途径与AR2的诱导和功能的连接 （目标2）。最后，以令人兴奋的初步数据为基础，我们将研究泌尿生殖的潜力 其覆盖过度抗酸性抗性的能力的压力，旨在识别有效的益生菌策略以防止 expec储层在阴道中形成（AIM 3）。完成这些目标将揭示如何指示杠杆 他们的多个AR系统可以过境主机和逃避淘汰，并将为我们的努力提供努力 制定有效的益生菌策略来预防，阴道定植和战斗 感染。