子宫内膜CD8+T细胞通过Fas通路促进滋养细胞侵袭的分子机制研究

Trophoblast invasion is a key process in embryo implantation. It has been suggested that CD8+T cells promote the invasive ability of trophoblast cells to favor embryo implantation. However, the underlying mechanism remains to be elucidated. Our preliminary results suggested that 1. Endometrial CD8+T cells in the implantation window were significantly reduced in patients with recurrent implantation failure (RIF). 2. CD8+T cells regulated trophoblast cells invasion and induced the expression of MMP-2/9 of trophoblast cells. Combined with published studies, we hypothesized that endometrial CD8+T cells promote trophoblast cells invasion and induce MMP-2/9 expression through Fas/FasL mediated- NF-κB and ERK pathways. The endometrial CD8+T cells in the implantation window will be utilized in this research. Through cell sorting using immunomagnetic beads, co-culture, trophoblast cells Matrigel invasion assay, Western-Blot and so on, this study will provide evidence to support the regulatory role of endometrial CD8+T cells during trophoblast invasion and the underlying molecular mechanisms. The expected finding will enrich the molecular mechanisms of immune regulation between maternal-fetal interface. The significant of this project will provide a novel scientific insight in developing a new effective target for the therapy of patients with RIF.

滋养细胞侵袭是胚胎种植的关键环节。证据显示CD8+T细胞可提高滋养细胞的侵袭力而利于胚胎种植，但其机制仍尚未明确。前期研究显示：1）反复种植失败（RIF）患者子宫内膜CD8+T细胞数目较正常女性显著降低，提示其可能在胚胎种植中发挥关键作用；2）内膜CD8+T细胞可促进滋养细胞的侵袭，并诱导滋养细胞MMP-2/9的表达。结合文献和前期研究推测：CD8+T细胞可能通过Fas-FasL介导的NF-κB和ERK通路诱导滋养细胞表达MMP-2/9，促进滋养细胞的侵袭，而利于胚胎种植。本课题以子宫内膜CD8+T细胞为研究模型，运用磁珠分选、细胞共培养、Matrigel侵袭实验、Western-Blot等检测CD8+T细胞对滋养细胞侵袭的调控作用及其分子机制。该研究将有助于明确CD8+T细胞对滋养细胞侵袭的调控作用及机制，进一步丰富母-胎界面免疫调控的分子机制，为RIF治疗提供理论依据和有效靶点。

当前随着环境污染加重，生活压力的增大等因素，不孕不育患者的数量逐年增加。辅助生殖技术(ART)是治疗不孕夫妇的一种有效的治疗手段，但临床妊娠率却始终徘徊在 60%左右，胚胎种植率仅25%左右。迄今为止，胚胎种植率低及种植失败的机制尚未完全阐明，临床亦无有效治疗措施，探索有效的治疗胚胎种植失败的新方案已经成为生殖界面对的重大科学难题。本研究发现反复种植失败患者子宫内膜CD8+T细胞数量显著升高，而外周血CD8+T细胞水平无明显变化。进一步研究提示慢性子宫内膜炎可显著增加子宫内膜CD8+T细胞数量，对其功能分析发现CD8+T细胞表达穿孔素和颗粒酶B无明显变化，而表达IFN-γ和TNF-α的水平显著增加，调节性CD8+（CD8+CD28-）T细胞数量无显著差异。这些结果揭示RIF患者子宫内膜CD8+T细胞数量显著升高，由此推测CD8+T细胞可能是导致RIF发生的病因之一。追踪RIF患者妊娠结局，结果显示CD8+T细胞过高，RIF患者临床妊娠率显著降低，提示CD8+T细胞影响胚胎种植，对CD8+T细胞过高的RIF患者行CsA治疗后，其临床妊娠率得到显著改善，提示CD8+T细胞可作为一个治疗RIF患者的有效靶点。本研究为提高胚胎种植率及妊娠成功率，保证母婴健康提供重要的理论指导和实验依据，有望为治疗生殖失败患者提供全新的治疗方案。