Gardnerella vaginalis: toxin production and pathogenesis

描述（由申请人提供）：细菌性阴道病（BV）是一种非常常见的阴道微生物菌群失调，影响>30%的所有妇女，在怀孕期间和非洲裔美国人群体中发病率更高。患有BV的妇女早产的风险大大增加，这是新生儿发病率和死亡率的主要原因，也是感染包括人类免疫缺陷病毒在内的性传播疾病的主要原因。尽管其对公共卫生具有重要意义，但BV的发病机制尚未完全了解。我们最近对阴道溶素（VLY）进行了表征，VLY是一种来自阴道加德纳菌（Gardnerella vagulosa）的胆固醇依赖性溶细胞素（一种存在于BV环境中的阴道粘膜上的细菌物种，被认为有助于疾病的发病机制），具有极好的人类特异性。推测该毒素可能是G.与BV发病机制相关的迷走神经损伤。在我们的初步数据中，我们已经确定了生殖道上皮细胞上VLY（人CD 59）受体的特征。将这种受体引入非易感细胞使其对VLY敏感。我们已经设计了一个转基因小鼠表达hCD 59受体，也构建了一个VLY嵌合体，是hCD 59-独立的。这些代表BV的候选体内模型。此外，我们还开发了G.包括转座子诱变。在目标1中，我们将定义G的遗传决定因素。使用诱变和毒素产生测定的新技术研究迷走神经毒性。在目标2中，我们将确定VLY在体外和体内宿主-病原体界面中的作用，重点关注VLY-hCD 59相互作用的独特方面。在这些研究的结论中，我们将扩大我们对G。迷走神经病变的发病机制，评估新的BV体内模型，确定候选策略，以抑制毒素-宿主相互作用，并开发新的工具，继续研究一个重要的疾病的发病机制。

DESCRIPTION (provided by applicant): Bacterial vaginosis (BV) is an exceedingly common disorder of the vaginal microflora affecting >30% of all women, with higher rates in pregnancy and among African- American populations. Women with BV are at substantially increased risk of preterm birth, which is a major cause of neonatal morbidity and mortality, as well as acquisition of sexually transmitted diseases including human immunodeficiency virus. Despite its public health importance, the pathogenesis of BV is not well understood. We have recently characterized vaginolysin (VLY), a cholesterol-dependent cytolysin from Gardnerella vaginalis (a bacterial species present on the vaginal mucosa in the setting of BV and thought to contribute to the pathogenesis of disease) that exhibits exquisite human specificity. We hypothesize that this species-specific toxin may be an important virulence factor of G. vaginalis with relevance to the pathogenesis of BV. In our preliminary data, we have characterized the receptor for VLY (human CD59) on genital tract epithelial cells. Introduction of this receptor into non-susceptible cells renders them sensitive to VLY. We have engineered a transgenic mouse expressing the hCD59 receptor and also constructed a VLY chimera that is hCD59-independent. These represent candidate in vivo models for BV. In addition, we have developed techniques for genetic manipulation of G. vaginalis, including transposon mutagenesis. In Aim 1, we will define genetic determinants of G. vaginalis virulence using new techniques for mutagenesis and assays of toxin production. In Aim 2, we will determine the role of VLY at the host-pathogen interface both in vitro and in vivo with a focus on unique aspects of the VLY-hCD59 interaction. At the conclusion of these studies, we will have expanded our knowledge of G. vaginalis pathogenesis, evaluated new in vivo models of BV, identified candidate strategies to inhibit toxin-host interaction, and developed new tools for continued investigation into the pathogenesis of an important disorder.