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

细菌性阴道病（BV）是育龄妇女中最常见的阴道疾病。细菌性阴道炎增加了妇女获得性传播疾病的风险，包括艾滋病毒，以及发展为不孕症和盆腔炎。在孕妇中，细菌性阴道炎增加了早产和妊娠中期和晚期流产的风险。此外，感染细菌性阴道炎的母亲所生的新生儿出现严重低出生体重、高炎症反应、长期发育问题和死亡率的风险较高。鉴于这种疾病的临床相关性，弥合目前对细菌性阴道炎发病和进展的不完整理解的空白是很重要的。细菌性阴道炎的症状几乎总是伴随着阴道细菌组成的剧烈变化。另一个常见的变化是阴道pH值升高（正常<4.5 vs.阴道pH值升高4.5）。这两种观察结果可能有因果关系，因为低pH值为病原体和其他细菌提供了物理屏障，这些细菌通常在健康的阴道中找不到，或者丰度很低。作者最近发现并发表了BV、两种多胺（腐胺和尸胺）水平升高和几种细菌属（包括Dialister、Prevotella和链球菌）之间的三方关系。氨基酸脱羧和多胺的产生是一种众所周知的细菌耐酸和缓解机制，我们假设它是BV发育过程中阴道pH值升高的原因。氨基酸脱羧消耗细胞内氢离子形成多胺，这些多胺通过氨基酸/多胺（AAP）特异性反转运蛋白主动泵送到细胞外。以aap为基础的耐酸性尚未在阴道微生物群中得到表征。因此，该项目建议通过宏基因组学确定阴道中独特氨基酸脱羧途径的丰度和广度，并确定编码这些途径的微生物物种，来解决上述假设；亚转录组学检测它们在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精确表征体外条件

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.