滋养层细胞外泌体来源的miR-424在子痫前期发病机制中的研究

The expression of miR-424 is significantly elevated in exosomes derived from trophoblast cells in patients with pre-eclampsia(PE). It is reported that Treg cells induced aberrant maternal-fetal immune tolerance is a critical factor in pathogenesis of PE. Our previous study showed that exosomes derived from PE patients' trophoblast cells could attenuate the immunosuppressive effects of Treg cells. The miR-424 is significantly higher in PE's exosomes. While Foxo1, the target gene of miR-424 predicted by bioinformatics, is reported to be a critical role in differentiation and regulation of Treg cells. Our research is designed to evaluate the expression of miR-424 and Foxo1 in trophoblast cells to clarify the effects of miRNA in exosomes on Treg cells and PE. The molecular mechanisms of miR-424, transported by exosomes derived from trophoblast cells, on regulating foxo1 in PE is investigated by inhibiting the formation of exosomes, overexpression and knock down the expression of miRNA-424, and rescue experiment. To date, there is no report about the trophoblast transport miR-424 exerts its biological function via exosomes. Our research is expected to provide new targets for the prevention and treatment of PE.

miR-424是我们采用miRNA测序技术筛选到的、显著高表达于子痫前期（PE）患者滋养层细胞外泌体的miRNA。已证实Treg细胞致母胎免疫耐受异常是PE发病的一个重要原因。前期研究发现：PE患者滋养层细胞外泌体可减弱Treg细胞免疫抑制功能；miR-424显著高表达于PE患者滋养层细胞外泌体；生物信息学预测Foxo1为miR-424靶基因；文献报道Foxo1在Treg细胞分化、调节中发挥重要作用。本研究拟：检测PE患者滋养层细胞外泌体中miR-424与蜕膜组织中Foxo1表达水平，评估miR-424与Treg细胞和PE之间的关系；通过抑制外泌体、过表达和沉默miR-424以及挽救策略，系统评判外泌体中miR-424通过调控Foxo1影响Treg细胞免疫抑制功能的分子机制。目前尚未见有关滋养层细胞通过外泌体转运miR-424发挥生物学功能的报道，本研究如获成功，有望为PE防治提供新靶标。

子痫前期（PE）是妊娠期常见并发症之一，可导致多种不良妊娠结局。PE的病因和发病机制尚不清楚，胎盘一直被认为是PE发病的重要因素。我们提取子痫前期（PE）患者胎盘和正常同孕龄孕妇胎盘滋养层细胞外泌体（exosomes），检测其形态标志物，筛选和验证差异性miRNAs的表达。结果发现，miR-424高表达于PE患者，miR-145-5p低表达于PE患者。我们分别选取miR-424和miR-145-5p进行下一步研究：检测PE患者胎盘滋养层细胞exosomes中miR-424的表达水平与蜕膜组织中Foxo1、Foxp3的表达水平，通过抑制exosomes的形成、过表达和表达沉默miR-424，探讨滋养层细胞exosomes通过转运miR-424参与PE发生的可能机制；检测miR-145-5p在PE胎盘中的表达，分别过表达和表达沉默miR-145-5p，检测滋养层细胞增殖能力、侵袭能力和迁移能力的变化，探讨miR-145-5p在PE发生发展中的作用和可能的分子机制。研究发现：1、滋养层细胞exosomes可能通过转运miR-424调控Foxo1影响Treg细胞功能，参与PE的发生；2、miR-145-5p可能通过调节FLT1表达影响滋养细胞的增殖和侵袭，参与PE的发生。以上结果提示胎盘来源的miR-424和miR-145-5p异常表达与PE发生密切相关。本研究从新的角度探寻了PE病因和发病机制，为PE的早期诊断和防治提供了新的思路。