Investigation of ERV-K-env expression and function in placentation

项目摘要/摘要 在整个怀孕期间，正常的胎盘形成对产前发育和双方母亲的健康至关重要。 还有宝贝。胎盘异常与几种常见的妊娠并发症密切相关，如 作为先兆子痫和早产，占#年新生儿死亡的35%和妊娠相关死亡的10%。 世界各地的女性。尽管在抗击这些疾病方面取得了一些进展，但我们对胎盘的理解 导致这些并发症的异常仍然缺乏，因为许多基本的分子和细胞 正常胎盘形成的潜在过程尚不完全清楚。最近，有越来越多的人 对内源性逆转录病毒(ERV)衍生蛋白在早期发育和 胎盘摆放。ERV是在哺乳动物基因组中发现的内源性病毒元件，与 源自古老的外源逆转录病毒。虽然基因组中的大多数ERV都高度突变和 由于缺乏表达病毒基因的能力，一些基因被证明含有保守的开放阅读框架(ORF)。 并编码类似病毒的蛋白质。在人类中，这些最显著的例子是Syncytin-1和Syncytin-2 胎盘是属于ERV-W和ERV-FRD的ERV包膜基因编码的蛋白质 分别是一家人。合胞素具有融合活性，这是正常胎盘形成过程中的关键。 母胎交界处外滋养层的形成和维持。最近，一种灵长类动物- ERV包膜蛋白ERV-K-env在滋养层细胞中也有表达 正常人类胎盘形成过程中的亚群。这种蛋白质来自ERV-K组，最年轻的 和最近扩展的ERV；与Syncytins不同的是，ERV-K在 人类基因组中预测的完整开放阅读框。最近使用ERV-K-env共识序列的研究发现 融合(FD)和免疫抑制(ISD)结构域与外源性 逆转录病毒，以及在其他类型的细胞中诱导融合和免疫抑制的固有能力。即使 ERV-K在人类早期发育过程中的活性一直是众多研究的重点，其原生表达 而ERV-K-env在灵长类胎盘中的作用在很大程度上被忽视了。建议的目标是 本研究旨在评估ERV-K-env在体外对灵长类滋养层细胞的融合作用，并对其特性进行研究。 阐明ERV-K-env在健康胎盘组织和病理胎盘组织中的表达变化。在AIM 1，我们将验证ERV-K-env在分离的灵长类胎盘滋养层细胞中发挥融合作用的假设 细胞。对于目标2，我们将检验在健康胎盘中观察到的ERV-K-env表达是 在早产期间显著改变，特别是在与ISD和/或FD减少一致的方式上 功能。本项目的最终目标是阐明ERV-K-env在正常灵长类动物中的功能。 胎盘植入是否在常见的妊娠并发症中起作用，并为未来的治疗奠定基础 针对ERV-K-env在胎盘中表达的研究。

PROJECT SUMMARY/ ABSTRACT Throughout pregnancy, normal placentation is central to prenatal development and the health of both mother and baby. Placental abnormalities are strongly associated with several common pregnancy complications, such as preeclampsia and preterm birth, responsible for ~35% of neonatal and 10% pregnancy-related deaths in women worldwide. Despite some progress in combating these diseases, our understanding of the placental abnormalities contributing to these complications is still lacking, since many of the basic molecular and cellular processes underlying normal placentation are not yet fully understood. Recently, there has been a growing interest in the biological role of endogenous retrovirus (ERV) derived proteins during early development and placentation. ERVs are endogenous viral elements found in the mammalian genome that closely resemble and are derived from ancient exogenous retroviruses. While most ERVs within the genome are highly mutated and lack the ability to express viral genes, some have been shown to contain conserved open reading frames (ORFs) and encode viral-like proteins. The most notable examples of these in humans are Syncytin-1 and Syncytin-2 in the placenta, proteins encoded by the envelope (env) gene of ERVs belonging to the ERV-W and ERV-FRD family, respectively. Syncytins possess fusogenic activity, which is critical during placentation for the normal formation and maintenance of the outer trophoblast layer at the maternal-fetal interface. Recently, a primate- specific ERV envelope protein, ERV-K-env, has also been shown to be expressed within trophoblast subpopulations during normal human placentation. This protein is derived from the ERV-K group, the youngest and most recently expanded ERV; unlike the Syncytins, ERV-K contains dozens of proviral insertions in the human genome with predicted intact ORFs. Recent studies using the ERV-K-env consensus sequence identified fusion (FD) and immunosuppression (ISD) domains closely resembling those found in exogenous retroviruses, and the inherent ability to elicit fusion and immunosuppression in other cell types. Even though ERV-K activity during early human development has been the focus of numerous studies, the native expression and function of ERV-K-env in primate placentation have largely been overlooked. The aims of the proposed studies are to assess the fusogenic role of ERV-K-env within primate trophoblasts in vitro and to characterize and elucidate changes in ERV-K-env expression within healthy and pathological placental tissues in vivo. In Aim 1, we will test the hypothesis that ERV-K-env plays a fusogenic role within isolated primate placental trophoblast cells. For Aim 2, we will test the hypothesis that ERV-K-env expression observed within the healthy placenta is significantly altered during preterm birth, specifically in a manner that is consistent with reduced ISD and/or FD function. The ultimate goals of this project are to elucidate the function of ERV-K-env in normal primate placentation, whether it has a role in common pregnancy complications, and set the stage for future therapeutic investigations targeting ERV-K-env expression in the placenta.