Mechanisms regulating episodic breaches of protective vaginal microbiome by BV

描述（由申请人提供）：在阴道微生物群健康的女性中，乳酸菌群落用乳酸使阴道酸化，乳酸是一种有效的广谱杀微生物剂，可增强粘膜屏障，防止性传播感染（STIs）。然而，对于全世界至少三分之一的女性（以及50%的黑人女性）来说，保护性乳酸菌被革兰氏可变菌和革兰氏阴性菌的密集混合物所取代，通常导致一种称为细菌性阴道病（BV）的疾病。细菌性阴道炎显著增加对几乎所有性传播感染的易感性，包括艾滋病毒。虽然BV可以用抗生素治疗，但复发很频繁，每月约2次。阴道细菌群落是如何在保护性乳酸菌和非保护性BV之间迅速转变的尚不清楚，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。研究结果可以指导制定预防细菌性感染的急需方法，从而大大降低性传播感染的传播率。总的假设是，这些变化是由乳酸菌和bv相关细菌之间的拮抗作用引起的，这些拮抗作用是由分泌抑制因子介导的；初步证据表明，乳酸菌分泌的乳酸和BV微生物分泌的胺可能是两个这样的因素。为了验证这一假设，qPCR分析将用于量化体外健康、乳酸菌主导的阴道分泌物中抑制BV相关细菌的抑制因子的特异性和效力，以及体外BV分泌物中抑制乳酸菌的抑制因子（目的1）。此外，BV发病的动力学（目的2）将

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.