Trichomonas pathogenesis: cell surface interactions

描述(申请人提供)：阴道毛滴虫是全世界最常见的非病毒性性传播感染(STI)的病原体，也是在美国人口中发现的最流行的寄生虫。艾滋病毒在长期感染这种寄生虫的妇女中的传播增加，以及最近耐药滴虫病发病率的增加，需要更好地了解这种未被研究的病原体的生物学。7.在美国市中心，阴道感染还与早产、低出生体重和婴儿死亡率增加有关。尽管阴道毛滴虫在全球医学上具有重要意义，但其发病的分子机制几乎是未知的。我们已经证明了包裹在这种寄生虫表面的糖萼在宿主细胞黏附和细胞毒性中的作用，并鉴定了第一个假定的阴道寄生虫宿主细胞受体。我们现在建议描述阴道和人类阴道上皮细胞(VECs)表面的分子，这些分子对宿主和寄生虫的相互作用可能是至关重要的。为此，我们建议(1)阐明野生型和突变型7.阴道表面糖结合物和脂磷聚糖(LPG)的结构，作为鉴定参与其组装的新酶的一步，(2)删除丝氨酸棕榈酰转移酶2(SPT2)基因以创建LPG缺失突变体，并确定对寄生虫黏附和细胞毒性的影响(3)验证合成和组装单糖所需的候选阴道基因，以及(4)检测7阴道LPG与宿主细胞Galectin-1(GAL-1)之间的相互作用，并研究这种相互作用是否在发病机制中发挥作用。除了提供关于这种流行的STI宿主-病原体相互作用机制的关键数据外，拟议的研究还将产生可能有助于开发新的药物疗法和疫苗接种策略的信息。

DESCRIPTION (provided by applicant): Trichomonas vaginalis is the etiologic agent of the most common non-viral sexually transmitted infection (STI) worldwide and is the most prevalent parasite found in the US population. Increased transmission of HIV in women chronically infected with this parasite and a recent increase in the incidence of drug resistant Trichomoniasis warrant a better understanding of the biology of this understudied pathogen. 7. vaginalis infections are also associated with pre-term delivery, low birth weight and increased infant mortality in inner city America. Despite its global medical importance, the molecular mechanisms underlying the pathogenesis of T. vaginalis are virtually unknown. We have demonstrated a role for the glycocalyx that coats the surface of this parasite in host cell adherence and cytotoxicity and have identified the first putative host cell receptor for 7 vaginalis. We now propose to characterize molecules on the surface of 7. vaginalis and human vaginal epithelia cells (VECs) that may be critical for host-parasite interactions. To this end, we propose to (1) elucidate the structure of wild-type and mutant 7. vaginalis surface glycoconjugates and lipophosphoglycan (LPG) as a step towards identifying novel enzymes involved in its assembly, (2) delete the serine palmitoyl transferase 2 (SPT2) gene to create LPG null mutants and determine the effect on adherence and cytotoxicity of the parasite (3) validate candidate7 vaginalis genes required for the synthesis and assembly of the monosaccharide rhamnose, an unusual sugar that is absent in host cells and (4) examine the interaction between 7 vaginalis LPG and host cell galectin-1 (gal-1) and investigate whether this interaction plays a role in pathogenesis. In addition to providing critical data on the mechanisms underlying host-pathogen interaction of this prevalent STI, the proposed studies will yield information that may be useful for developing novel drug therapies and vaccination strategies.