Microbial Polyamine-Mediated Reductions in Vaginal Acidity; A Mechanistic Underst

描述(申请人提供)：细菌性阴道病(BV)是育龄妇女中最常见的阴道疾病。BV增加了妇女获得性传播疾病的风险，包括艾滋病毒，以及发展为不孕不育和盆腔炎。在孕妇中，BV增加了早产和中期和晚期妊娠流产的风险。此外，患有BV的母亲所生的新生儿具有极低出生体重、高炎症反应、长期发育问题和死亡率的风险。鉴于这种疾病的临床相关性，弥合目前对BV发生和发展的不完全了解的差距是很重要的。BV症状几乎总是伴随着阴道细菌组成的戏剧性变化而观察到。另一个普遍观察到的变化是阴道pH值升高(正常与BV&GT；4.5相比)。这两个观察结果可能是有因果关系的，因为低pH值为病原体和其他细菌物种提供了物理屏障，这些细菌或在健康的阴道中通常不存在，或处于低丰度。作者最近发现并发表了BV、两种多胺(腐胺和身体碱)水平增加与几个细菌属之间的三方关联，包括Dialister、Prevoella和Strestreball。氨基酸脱羧基和多胺的产生是众所周知的细菌耐酸和缓解机制，我们推测这是在BV发育过程中导致阴道pH值升高的原因。氨基酸脱羧基消耗细胞内的氢离子形成多胺，这些多胺通过氨基酸/多胺(AAP)特异性的逆向转运蛋白被主动泵到细胞外。以AAP为基础的耐酸性尚未在阴道微生物区系中得到表征。因此，该项目建议通过元基因组学方法确定阴道中独特的氨基酸脱酸途径的丰度和广度，并鉴定编码这些途径的微生物物种；通过元翻译方法确定它们在BV之前、期间和之后的转录活性；最后通过分离重要的阴道菌株和准确地描述体外条件，来解决上述假设。 这导致了AAP途径的利用。

DESCRIPTION (provided by applicant): Bacterial vaginosis (BV) is the most common vaginal disorder among reproductive age women. BV increases a woman's risk of acquiring sexually transmitted diseases, including HIV, as well as developing infertility and pelvic inflammatory disease. In pregnant women, BV increases the risk of pre-term birth and second- and third-trimester abortion. Additionally, neonates born to mothers with BV have elevated risks of critically low birth weights, hyper-inflammatory responses, long-term developmental problems, and mortality. Given the clinical relevance of this disease, it is important to bridge gaps in the currently incomplete understanding of BV onset and progression. BV symptoms are almost always observed alongside a dramatic change in the composition of vaginal tract bacteria. Another commonly observed change is an increase in vaginal pH (normal <4.5 vs. BV>4.5). These two observations may be causally related because low pH provides a physical barrier to pathogens and other bacterial species that are either not normally found, or are at low abundances, in the healthy vaginal tract. The authors recently identified and published a tripartite association between BV, increased levels of two polyamines (putrescine and cadaverine), and several bacterial genera, including Dialister, Prevotella, and Streptococcus. Amino-acid decarboxylation and polyamine production is a well-known bacterial acid resistance and mitigation mechanism and we hypothesize it is responsible for increasing vaginal pH during BV development. Amino acid decarboxylation consumes intracellular hydrogen ions to form polyamines that are actively pumped outside the cell via amino acid/polyamine (AAP)-specific antiporters. AAP-based acid resistance has yet to be characterized among the vaginal microbiota. This project therefore proposes to address the above hypothesis by metagenomically determining the abundance and breadth of unique amino-acid decarboxylation pathways in the vaginal tract and identifying the microbial species encoding them; metatranscriptomically determining their transcriptional activity before, during and after BV; and finally by isolating important vaginal strains and precisely characterizing the in vitro conditions that lead to AAP pathway utilization.