SGK1调控蜕膜巨噬细胞极化在自然流产母胎界面免疫微环境中的作用机制研究

The causes of miscarriage have been attributed to many factors with complex pathogenesis. The polarizations of the decidual macrophages are critical to the immune microenvironment at the feto-maternal interface during pregnancy. The abnormal differentiation of the decidual macrophages may adversely affect gestation maintenance and predispose immune maladaptation notably in miscarriages. However the mechanism involved remains poorly understand. Our group has found that the serum-glucocorticoid regulated kinase 1 (SGK1) was down-regulated in the decidual macrophages of early miscarriage when compared with normal pregnancy. Moreover, SGK1 was found to be activated via the PI3K signaling in decidual stromal cells. And its suppression by small interfering (si) RNA induced M1 polarization of the decidual macrophages. PI3K signaling has been reported to facilitate the M2 differentiation of macrophages by inhibiting NF-KB activities. Here, we propose that SGK1 induces M2 polarization of the decidual macrophages through PI3K/NF-KB signaling to favor the immune balance of intrauterine microenvironment and prevent miscarriage. In this study, we plan to employ cells and mice models with SGK1 siRNA and gene over-expression pretreatments. By applying techniques in molecular and cell biology, we will investigate the mechanisms of SGK1 in promoting the polarizations of decidual macrophages via the PI3K/NF-KB signaling. Furthermore, this study will demonstrate the prominent role of SGK1 in the immune balance of intrauterine microenvironment. Finally, this study will evidence the role of SGK1 in miscarriage from the levels of histology, cell, animal and molecule. In summary, the findings of this study may provide new mechanisms for the causes of miscarriage, thereby can pave the way to new interventions for miscarriage.

自然流产发病机制复杂。蜕膜巨噬细胞极化是母胎界面免疫微环境调节的重要因素，直接影响自然流产的发生，其调控机制尚未明了。我们前期研究发现自然流产蜕膜巨噬细胞中血清和糖皮质激素调节蛋白激酶1（SGK1）的表达下降，SGK1经PI3K通路激活，干扰其表达增加蜕膜巨噬细胞M1型极化。文献报道激活PI3K可抑制NF-KB活性促使巨噬细胞M2型极化。据此假设：SGK1经PI3K通路激活，调控其下游NF-KB的转录活性，诱导蜕膜巨噬细胞M2型极化，促进母胎界面免疫微环境的动态平衡，维持正常妊娠以免发生自然流产。我们拟通过建立基因沉默和过表达模型，从组织、细胞、动物、分子四个层面，采用分子生物学及细胞生物学技术，分析SGK1调控蜕膜巨噬细胞M2型极化的效应途径，阐明SGK1调节母胎界面免疫微环境平衡的机制，明确SGK1对自然流产发生的影响。本研究将为自然流产的发病提供新的机理，为防治自然流产提供干预靶点。

摘要：自然流产是临床常见疾病，其病因众多，其中母胎界面免疫微环境的失调被认为自然流产发病的重要因素之一。近年的研究表明，母体对胚胎的免疫识别和耐受不是持续性的母体免疫抑制，而是一种动态的平衡，母胎界面免疫微环境是维持这种平衡的关键因素之一。母胎界面免疫微环境的建立涉及多种组织，蜕膜是其中数量最多的异质性组织，蜕膜巨噬细胞作为蜕膜免疫细胞中第二大细胞群，在以蜕膜为中心构成的母胎界面免疫微环境中起着重要作用。我们的临床研究结果阐明了妊娠早期血清雌二醇水平的下降以及蜕膜组织SGK1的活性下调与自然流产的发生有关。我们发现自然流产蜕膜组织的巨噬细胞成M1型表型增加，自然流产蜕膜巨噬细胞中血清和糖皮质激素调节蛋白激酶1（SGK1）的表达下降，体外细胞模型中我们发现干扰SGK1的表达促使M1型巨噬细胞的表型增加。我们通过建立体外蜕膜细胞模型，发现干扰SGK1的表达增加蜕膜细胞的凋亡，阐明雌二醇可通过雌激素受体b（ERb）上调蜕膜基质细胞中SGK1蛋白表达水平，并可通过PI3K信号通路激活SGK1的活性，促使母胎界面免疫微环境中免疫细胞因子从Th1型为主向Th2型偏移。在巨噬细胞模型中，SGK1经PI3K信号被雌二醇激活后，调控其下游NF-KB的活性，调节巨噬细胞功能，使巨噬细胞向有利于维持妊娠的M2型表型偏倚，促进母胎界面免疫微环境的动态平衡，减少自然流产的发生。本研究阐明了SGK1促进母胎界面免疫微环境动态平衡的机制，为自然流产的实验室诊断以及临床干预提供依据。