Trichomonas vaginalis exosomes: Mediators of host:pathogen interactions

描述(申请人提供)：单细胞寄生虫阴道毛滴虫是全世界最流行的非病毒性性传播感染，每年报告约1.7亿滴虫病病例。仅在美国，每年的发病率估计为300-500万例。除了感染人类泌尿生殖道外，滴虫病还会增加不良妊娠结局、艾滋病毒传播以及宫颈癌和前列腺癌的发病率和严重性。它的流行和最近耐药阴道毛滴虫菌株数量的增加突显了开发新的化疗和疫苗设计策略的必要性。要实现这些目标，必须更好地理解传染性和致病过程，就像这里提出的那样。我们已经发现，阴道毛滴虫分泌小的、膜结合的囊泡，称为外体，能够与宿主细胞融合并将蛋白质输送到宿主细胞中。寄生虫外切体也可以调节宿主细胞的反应。我们观察到的外切体介导的宿主：病原体相互作用是一个全新的研究领域，有望揭示有趣的、新颖的机制。我们的目标是进一步描述exosome：宿主细胞的相互作用，并研究exosome对全球宿主细胞反应的影响。为此，我们的研究将集中在鉴定外切体与宿主细胞的融合以及外切体对宿主细胞基因和蛋白表达的调控。该提案的具体目的是：目的1：确定保守的外体膜蛋白Tetraspanin 1是否在外体与宿主细胞的融合中发挥重要作用，以及这是否通过选择特定的外体膜相关蛋白来调节。目的2：确定阴道毛滴虫高黏附性和溶细胞性菌株的外切体是否能增加弱黏附性/溶细胞性菌株黏附和/或溶解阴道上皮细胞的能力。还将对这些菌株的外体蛋白质组进行比较，以确定参与黏附和细胞溶解的候选蛋白质。目的3：[研究]阴道毛滴虫外切体如何通过改变目标人阴道上皮细胞的基因和蛋白表达来调节宿主细胞的反应。这些研究将极大地提高我们对流行的人类病原体感染性和致病机制的理解，并很有可能揭示这种寄生虫用来调节宿主：病原体相互作用的新机制。由于外切体也是由哺乳动物细胞产生的，并且已知在正常和病理细胞功能中都发挥着关键作用，我们从拟议的研究中所学到的可能也有助于更好地理解外切体在发育、抗原呈递、免疫调节和癌症转移中的作用。

DESCRIPTION (provided by applicant): The unicellular parasite Trichomonas vaginalis is responsible for the most prevalent non-viral sexually transmitted infection worldwide, with approximately 170 million cases of trichomoniasis reported annually. In the US alone, the annual incidence is estimated at 3-5 million cases. In addition to infecting the human urogenital tract, trichomoniasis increases the risk of adverse pregnancy outcomes, HIV transmission and the incidence and severity of cervical and prostate cancers. It's prevalence and the recent increase in the number of drug resistant T. vaginalis strains underscore the need to develop new chemotherapeutic and vaccine design strategies. A much better understanding of processes involved in infectivity and pathogenesis, such as those proposed here, will be imperative to achieve these goals. We have discovered that T. vaginalis secretes small, membrane-bound vesicles, called exosomes, which are capable of fusing with and delivering proteins into the host cell. Parasite exosomes can also modulate host cell responses. The exosome-mediated host:pathogen interactions that we observed is an entirely new area of research that promises to uncover interesting, novel mechanisms. Our objectives are to further characterize exosome:host cell interactions and investigate the effect of exosomes on global host cell response. To this end, our studies will focus on characterizing exosomal fusion with host cells and exosome-mediated modulation of host cell gene and protein expression. The specfic aims of the proposal are: Aim 1: Determine whether the conserved exosomal membrane protein, tetraspanin 1, plays a vital role in exosome fusion with host cells and if this is mediate by selection of specific exosomal membrane-associated proteins. Aim 2: Determine whether exosomes from highly adherent and cytolytic T. vaginalis strains increase the ability of weakly adherent/cytolytic strains to adhere to and/or lyse vaginal epithelial cells. The exosomal proteomes of these strains will also be compared to identify candidate proteins involved in adherence and cytolysis. Aim 3: [Examine how] T. vaginalis exosomes modulate host cell responses by altering gene and protein expression in target human vaginal epithelial cells. These studies will greatly enhance our understanding of processes underlying the infectivity and pathogenesis of a prevalent human pathogen and have a high probability of revealing novel mechanisms used by the parasite to mediate host:pathogen interactions. As exosomes are also produced by mammalian cells and are known to play critical roles in both normal and pathological cellular functions, what we learn from the proposed studies is likely to also contribute to a better understanding of the role of exosomes in development, antigen presentation, immune modulation and cancer metastasis.