妊娠子宫蜕膜组织激活素应答中性粒细胞亚群特征鉴定及其功能研究

The decidua of uterus in pregnancy is composed of endometrial glandular epithelial cells, decidual stomal cells and decidual immune cells that mainly include NK cells, T cells, monocytes/macrophages and a small number of neutrophils. Recent studies have suggested that the aberrant activation of decidual neutrophils (dNs) is related to pregnancy-associated diseases. However, the alteration in functional subsets and activities of dNs during pregnancy is not well characterized. On the other hand, the levels of activin A as a regulatory protein of sex hormone that can promote the secretion of follicle stimulating hormone (FSH) by pituitary cells have been found to be obvious increase in serum and decidual tissues of uterus during pregnancy. Our latest studies have revealed that a new neutrophils subset exists which responds to activin with expression of type IIA receptor of activin (IIA+ neutrophils) in human and mouse, and the chemotaxis of human and mouse neutrophil to N-Formyl-Met-Leu-Phe (fMLP) can be inhibited by activin A. Therefore, we speculate that the quantity of dNs and the activation of dNs subsets might be determined by the high levels of activin A in local decidual tissues in pregancy. In the present study, the quantities, activities and characteristic molecules expressions of IIA+ and IIA- neutrophil subsets in peripheral blood and decidual tissues of pregnant mice will be first compared in the different gestation period. Then, we will determine whether the IIA+ dNs subsets in decidual tissues are the long-lived neutrophils and have immunosuppressive or immunoenhancemental effect. Third, the role of activin A in the process of domestication of neutrophils from peripheral blood to form dNs is studied by co-culture of decidual tissue cells with neutrophils. In addition, we will analyze the relationship between abortion and changes of IIA+dNs subset activities regulated by activin A in abortion mouse models. It is hoped that the study will not only reveal that a new subset of neutrophils exists in decidua of uterus, but also supplement a novel mechanism in the development of abortion.

子宫蜕膜组织由蜕膜腺上皮细胞、基质细胞和免疫细胞组成，免疫细胞主要包括NK细胞、T细胞、单核巨噬细胞及少量中性粒细胞。近年研究显示蜕膜中性粒细胞（dNs）异常活化与妊娠疾病有关，但在妊娠过程中dNs功能亚群及活性变化仍未完全阐明。激活素A（Activin A）作为促进FSH分泌的性激素调节蛋白，在妊娠期女性外周血及子宫蜕膜组织中水平显著升高。我们最新研究发现，存在新的激活素应答中性粒细胞（IIA+）亚群，而且激活素A能抑制细菌产物fMLP诱导的中性粒细胞趋化。据此推测，妊娠期子宫蜕膜组织高水平激活素A，可能是决定dNs数量及亚群活化的重要因素。因此，本研究首先分析妊娠不同时期孕鼠外周血及子宫蜕膜组织IIA+和IIA-中性粒细胞亚群细胞数量、活性及特征分子表达，确定IIA+dNs亚群是否是长寿命中性粒细胞、是具有免疫抑制还是免疫促进功能的中性粒细胞，以及激活素A在蜕膜组织驯化中性粒细胞过程中的作用；其次利用流产模型小鼠探讨激活素A体内调控IIA+dNs活性变化与流产的关系。上述研究不仅揭示蜕膜组织存在新的中性粒细胞功能亚群，而且对进一步阐述流产的发生发展机制也具有重要意义。

子宫蜕膜组织由蜕膜腺上皮细胞、基质细胞和免疫细胞组成，免疫细胞主要包括NK细胞、T细胞、单核巨噬细胞以及少量中性粒细胞。近年研究显示蜕膜中性粒细胞（dNs）异常活化与妊娠疾病有关，但在妊娠过程中dNs功能亚群及活性变化仍未完全阐明。激活素A（Activin A）作为促进FSH分泌的性激素调节蛋白，在妊娠期女性外周血及子宫蜕膜组织中其水平显著升高。我们最新研究发现，存在激活素应答中性粒细胞，而且激活素A能抑制细菌产物fMLP诱导的中性粒细胞趋化。据此推测，妊娠期子宫蜕膜组织高水平激活素A，可能是决定dNs数量及亚群活化的重要因素。因此，本研究首先制备了正常妊娠及流产模型小鼠，分析了正常妊娠及流产模型小鼠外周血及蜕膜组织激活素A及激活素结合蛋白——卵泡抑素（Follistatin，FST）水平变化情况，同时检测了妊娠不同时期孕鼠以及流产模型小鼠外周血及子宫蜕膜组织激活素IIA型受体表达（IIA+）和不表达（IIA-）中性粒细胞亚群数量动态变化情况，发现IIA+/IIA-中性粒细胞亚群比率及活性变化在维持正常妊娠中至关重要，流产模型小鼠蜕膜组织IIA+中性粒细胞亚群比率显著下降。进一步利用纯化中性粒细胞，通过细胞密度以及细胞内细胞因子染色等技术，发现IIA+和IIA-中性粒细胞不仅细胞密度、细胞表面分子表达不同，其分泌的细胞因子类型也显著不同，小鼠IIA+中性粒细胞主要分泌具有免疫调节作用的TGF-β1和IL-10，在母胎免疫耐受维持中发挥主要作用。研究还发现激活素A及其结合蛋白FST不仅可以共同调控中性粒细胞迁移，还能共同调控子宫蜕膜基质细胞迁移，进而影响子宫蜕膜化形成。上述研究不仅揭示蜕膜组织存在新的中性粒细胞功能亚群，而且对进一步阐述免疫性流产的发生发展机制也具有重要意义。