Mechanisms regulating episodic breaches of protective vaginal microbiome by BV

描述（由申请人提供）：在具有健康阴道微生物组的女性中，乳酸菌群用乳酸酸化阴道，乳酸是一种有效的广谱杀微生物剂，可加强对性传播感染（STI）的粘膜屏障。然而，对于全球至少三分之一的女性（以及> 50%的黑人女性）来说，保护性乳酸杆菌被革兰氏可变菌和革兰氏阴性菌的密集混合物所取代，通常导致称为细菌性阴道病（BV）的病症。BV显著增加了对几乎所有性传播感染，包括艾滋病毒的易感性。虽然BV可以用抗生素治疗，但复发频繁，每月约2次BV发作。阴道细菌群落如何在保护性乳酸杆菌和非保护性BV之间迅速转变尚不清楚，目前也没有预防BV的方法。该项目旨在确定导致阴道细菌群落之间快速变化的因素。这些结果可能会指导开发急需的方法来预防BV，从而大大降低STI传播率。总体假设是，这些变化是由乳酸杆菌和BV相关细菌之间的拮抗作用，由分泌的抑制因子介导的;初步证据表明乳酸杆菌分泌的乳酸和BV微生物分泌的胺，可能是两个这样的因素。为了检验这一假设，将使用qPCR分析来定量存在于离体健康的乳酸杆菌主导的阴道分泌物中的抑制因子对BV相关细菌的特异性和效力，以及相反地，在离体BV分泌物中抑制乳酸杆菌的因子（目的1）。此外，BV发作的动力学（目标2）将 通过监测月经期间或阴道冲洗后阴道分泌物中乳酸杆菌的消耗和BV相关细菌抑制的减少（与BV发作相关的两起事件）进行研究。同样，BV缓解（目的3）将通过监测BV发作后乳酸杆菌恢复时阴道分泌物中的拮抗抑制因子来研究。使用新鲜的、扰动最小的离体阴道分泌物来研究抑制因子的作用代表了一项重大创新;大多数先前的研究都是在体外生长培养基中进行的，这未能捕获体内存在的细胞（包括共生微生物群落）、抑制因子和粘液的独特混合物。

DESCRIPTION (provided by applicant): In women with a healthy vaginal microbiome, lactobacillus communities acidify the vagina with lactic acid, a potent and broad-spectrum microbicide that reinforces the mucosal barrier to sexually transmitted infections (STIs). However, for at least one-third of women worldwide (and >50 percent of black women), protective lactobacilli are displaced by a dense mixture of Gram-variable and Gram-negative bacteria, often leading to a condition known as bacterial vaginosis (BV). BV markedly increases susceptibility to virtually all STIs, including HIV. Although BV can be treated with antibiotics, relapse occurs frequently, with ~2 BV episodes per month. How vaginal bacterial communities shift rapidly between protective lactobacilli and unprotective BV is not understood, and no method currently exists for preventing BV. This project seeks to identify factors that cause the rapid shifts between vaginal bacterial communities. The results may guide the development of much needed methods to prevent BV and thereby substantially reduce STI transmission rates. The overall hypothesis is that these shifts result from antagonistic actions between lactobacilli and BV-associated bacteria that are mediated by secreted inhibitory factors; preliminary evidence suggests lactic acid secreted by lactobacilli, and amines secreted by BV microbes, may be two such factors. To test this hypothesis, qPCR analysis will be used to quantify the specificity and potency of inhibitory factors present in ex vivo healthy, lactobacillus-dominated vaginal secretions against BV-associated bacteria, and conversely factors in ex vivo BV secretions that inhibit lactobacilli (Aim 1). In addition, the dynamics of BV onset (Aim 2) will be investigated by monitoring the depletion of lactobacilli, and the decrease in inhibition of BV-associated bacteria in vaginal secretions during menses or following vaginal douching (two events associated with BV onset). Similarly, BV remission (Aim 3) will be studied by monitoring antagonistic inhibitory factors in vaginal secretions as lactobacilli recover following a BV episode. The use of fresh, minimally-perturbed ex vivo vaginal secretions to investigate the actions of inhibitory factors represents a significant innovation; most prior research has been performed in vitro in growth media, which fails to capture the unique mixture of cells (including symbiotic microbial communities), inhibitory factors and mucus fluid present in vivo.