Molecular T. vaginalis-host interactions in relevance to inflammatory sequelae

描述(申请人提供)：滴虫病是最常见的非病毒性性传播感染(STI)，每年影响全球超过1.8亿人和800-1000万美国人。它使妇女容易早产、低出生体重、宫颈癌、严重炎症，并增加感染艾滋病毒-1的风险。在大约一半的女性中，感染是无症状的，通常是复发的，没有持久的免疫力，这表明了先天免疫防御的重要性。阴道毛滴虫的主要细胞表面糖结合物--阴道毛滴虫脂多糖(LPG)的分离和纯化，使我们能够研究这种寄生虫与复杂的阴道环境之间的新的分子相互作用。LPG是一种糖基磷脂酰肌醇类锚定分子，与其他GPI类寄生分子不同，不含甘露糖，具有多-N-乙酰乳糖胺重复序列。我们首次证明LPG在寄生虫的黏附和向正常人类阴道上皮细胞的信号传递中发挥关键作用。我们最新的发现表明，LPG与阴道上皮细胞表达的Galectins结合，并可能与细菌性阴道病(BV)的特定阴道微生物群组分协同作用，细菌性阴道病是一种已知增加艾滋病毒感染易感性的疾病。我们已经确定液化石油气的结构域，神经酰胺磷脂酰肌醇-葡聚糖核心(cpi-GC)，m/z为8695.5，是一个潜在的半乳糖凝集素配体，负责阴道和宫颈上皮细胞的促炎激活。我们推测阴道毛滴虫LPG，特别是其PI-GC，通过结合生殖器粘膜和宿主免疫系统中相反功能的Galectins来调节宿主的免疫炎症环境，这些事件可能是由BV相关的微生物群促进的。为了验证这一假设，我们建议使用一个与生理相关的体外模型系统，并将我们的实验结果与预期收集的患有和不患有BV的妇女在感染TV和HIV-1之前和之后的免疫反应相关联。我们的具体目标是：1)确定Galectins作为阴道天然免疫调节剂和阴道毛滴虫LPG的宿主受体的作用，并在正常和BV相关微生物区系的背景下确定相关信号通路在宫颈阴道上皮细胞中的作用；2)进一步阐明LPG的生化结构和负责Galectin结合和信号转导的CPI-GC亚域；以及3)识别和验证并发滴虫病和细菌性阴道病中可能增加HIV感染风险的阴道免疫变化的分子模式。建议的研究将扩大对阴道毛滴虫免疫逃避的理解。它将阐明与滴虫病和BV相关的HIV-1风险增加的潜在机制，验证阴道免疫失调的诊断和预后生物标志物，并为新的预防和治疗策略铺平道路。与公共卫生相关：阴道毛滴虫是世界上最常见的非病毒性性传播疾病(滴虫病)之一，它使妇女容易感染艾滋病毒-1、早产和癌症；全世界每年有超过1.8亿人感染，其中包括800-1000万美国人。随着寄生虫对抗生素耐药性的上升，基于分子医学的进步开发新的预防策略是至关重要的。这项名为《阴道毛滴虫-宿主相互作用与炎性后遗症相关的分子机制》的研究旨在揭示寄生虫-宿主相互作用与炎症症状和感染易感性相关的分子机制。

DESCRIPTION (provided by applicant): Trichomoniasis is the most common non-viral sexually transmitted infection (STI) affecting annually over 180 million people worldwide and 8-10 million Americans. It predisposes women to pre-term delivery, low birth weight, cervical cancer, severe inflammation, and increased risk of HIV-1 infection. In about half of the women the infection is asymptomatic and is often recurrent with no lasting immunity suggesting the importance of the innate immune defenses. The isolation and purification of the predominant cell surface glycoconjugate of the parasite, the T. vaginalis (TV) lipophosphoglycan (LPG), has allowed us to study novel molecular interactions between the parasite and the complex vaginal environment. LPG is a glycosylphosphatidyl inositol-like anchored molecule, which unlike other GPI-like parasitic molecules, contains no mannose and has poly-N-acetyllactosamine repeats. We were the first to show that LPG plays a key role in the parasite adhesion and signaling to normal human vaginal epithelial cells. Our latest novel findings suggest that LPG binds galectins expressed by vaginal epithelial cells and may synergize with selected vaginal microflora components specific for bacterial vaginosis (BV), which is a condition known to increase susceptibility to HIV infection. We have identified the structural domain of LPG, the ceramide phosphatidyl-inositol-glycan core (CPI-GC) with m/z 8695.5, as a potential galectin ligand responsible for proinflammatory activation of vaginal and cervical epithelial cells. We hypothesize that T. vaginalis LPG, especially its PI-GC, modulate the host immunoinflammatory environment via binding galectins with opposing functions in the genital mucosa and host immune system and that these events may be facilitated by BV-associated microflora. To test this hypothesis we propose to use a physiologically relevant in vitro model system and correlate our experimental findings with immune responses in a prospectively collected cohort of women with and without BV followed before and after infection with TV and HIV-1. Our specific aims are to: 1) define the roles of galectins as vaginal innate immunity modulators and host receptors for T. vaginalis LPG and identify related signaling pathways operating in the cervicovaginal epithelial cells in the context of normal and BV-associated microflora; 2) elucidate further the biochemical structure of LPG and the CPI-GC subdomains responsible for galectin binding and signaling; and 3) identify and validate molecular patterns of altered vaginal immunity in concurrent trichomoniasis and bacterial vaginosis that may enhance HIV infection risk. The proposed research will expand the understanding of the immune evasion by T. vaginalis. It will elucidate mechanisms underlying increased HIV-1 risk in relations to trichomoniasis and BV, validate diagnostic and prognostic biomarkers of vaginal immune dysregulation and pave the way to novel prevention and treatment strategies. PUBLIC HEALTH RELEVANCE: Trichomonas vaginalis is one of the most common non-viral sexually transmitted infections (trichomoniasis) in the world, which predisposes women to HIV-1 infection, preterm delivery and cancer; over 180 million people world-wide, including 8-10 million Americans become infected annually. With antibiotic resistance to the parasite on the rise, the development of novel prevention strategies based on the advances of molecular medicine is critical. The objective of this study entitled "Molecular T. vaginalis-host interactions in relevance to inflammatory sequelae" is to unveil molecular mechanisms of parasite-host interactions associated with inflammatory symptoms and susceptibility to infection.