Roles of sialidase in G. vaginalis-host interactions during bacterial vaginosis

项目摘要/摘要： 在美国，三分之一的女性患有细菌性阴道病(BV)，这种疾病与患上 生殖道感染和早产。BV的特征是乳酸菌和多菌群的丧失 多种潜在病原体过度生长，包括阴道加德纳氏菌。阴道唾液酸酶活性在 几乎所有女性都患有BV，并且与不良后果独立相关。然而，人们对此知之甚少 关于唾液酸酶如何支持生物失调和疾病。这项建议研究了唾液酸酶是如何由 阴道球虫某些亚型参与阴道和宫内感染的分子发病机制 并鼓励各种BV细菌的过度生长。 我们已经确定了G.V.的遗传基础。唾液酸酶活性，发现80%的BV患者有G.V.编码 唾液酸酶基因nanH2或nanH3，以及80%患有nanH2阳性或H3阳性阴道微生物群的女性 有了BV。我们的数据表明，通用汽车。唾液酸酶从根本上改变了BV的细胞糖链格局 结果表明，多糖的降解促进了病原菌的定植。在三个具体目标中，这项提议将 使用人类阴道样本，不同的G.V.复制BV相关特征的小鼠模型--分离株，新 野生型和配对的nanH3突变体G.V.菌株，以及使用天然人阴道的新的体外模型 社区检验关于阴道毛滴虫唾液酸酶在病因中分子机制的几个假设 BV的并发症。在目标1中，我们将考察G.V.分支生物化学和 人类临床样本的细胞表型，比较唾液酸酶阳性和阴性G.V.Clade和一个 通用汽车。唾液酸酶突变在我们的小鼠阴道定植模型中。在目标2中，我们将使用我们的活动本机存储库 在体外测试阴道群落如何获得游离唾液酸和暴露的多糖，两者都 唾液酸酶活性的后果，影响BV群落组成，并检查它们之间的关系 在NanH2/H3阳性的G.V.之间以及临床标本的细菌载量和多样性。最后，目标3我们将 评估孕妇纵向队列中的样本，以确定继续进行 经历早产有较高水平的阴道nanH2/H3阳性G.V.，更多的剥落 上皮细胞、降解的粘液和上皮性多糖，以及更多样化的微生物群，阴道更高 细菌负荷与定期对照的比较。这些目标的成功实现将具有重要的 通过识别G.V.对该领域产生积极影响。驱动病理生理学的亚型，通过 哪个通用汽车。唾液酸酶支持生物失调和疾病的发展，并识别可能 用于预防早产的临床监测工作。

PROJECT SUMMARY/ABSTRACT: One-third of women in the U.S. have bacterial vaginosis (BV), a condition associated with greater risks of reproductive tract infections and preterm birth. BV is characterized by loss of lactobacilli and polymicrobial overgrowth of diverse potential pathogens, including Gardnerella vaginalis. Vaginal sialidase activity is found in nearly all women with BV and is independently associated with adverse outcomes. However, little is known regarding how sialidase supports dysbiosis and disease. This proposal examines how the sialidase produced by certain subtypes of G. vaginalis participates in the molecular pathogenesis of vaginal and intrauterine infection and encourages overgrowth of diverse BV bacteria. We have identified the genetic basis of G.v. sialidase activity and found that 80% of BV cases have G.v. encoding the sialidase genes nanH2 or nanH3, and 80% of women with nanH2-positive or H3-positive vaginal microbiota have BV. Our data suggests that G.v. sialidase fundamentally transforms the cellular glycan landscape in BV and shows that glycan degradation encourages pathogen colonization. In three specific aims, this proposal will use human vaginal samples, diverse G.v. isolates, a mouse model that replicates relevant features of BV, new wild-type and paired nanH3 mutant G.v. strains, and novel ex vivo models employing native human vaginal communities to test several hypotheses about the molecular mechanism of G. vaginalis sialidase in the causes and complications of BV. In Aim 1, we will examine the relationship between G.v. clades and biochemical and cellular phenotypes in human clinical samples and compare sialidase positive and negative G.v. clades and a G.v. sialidase mutant in our mouse vaginal colonization model. In Aim 2, we will use our repository of live native vaginal communities in vitro to test how the availability of free sialic acid and exposed glycans, both consequences of sialidase activity, influence BV community composition and also examine the relationship between nanH2/H3-positive G.v. and bacterial burden and diversity in clinical specimens. Finally, Aim 3 we will evaluate samples from a longitudinal cohort of pregnant women to determine whether women who went on to experience preterm birth have higher levels of vaginal nanH2/H3-positive G.v., larger numbers of exfoliated epithelial cells, degraded mucus and epithelial glycans, and more diverse microbiomes with higher vaginal bacterial burden compared to term controls. The successful completion of these aims will have an important positive impact on this field by identifying G.v. subtypes that drive pathophysiology, defining mechanisms by which G.v. sialidase supports the development of dysbiosis and disease, and identifying biomarkers that might be used in clinical surveillance efforts to prevent preterm birth.