HIF-1α/CXCR4信号通路调控缺氧诱导的DMSCs过度向外迁移导致子痫前期的机制研究

Preeclampsia (PE) is a serious threat to maternal and fetal life. Systemic immuno-inflammatory responses resulted from maternal immune imbalance play central role in the pathogenesis of PE. The insufficient number of decidua-derived mesenchymal stem cells (DMSCs), which maintain maternal immune balance, is an important cause of immune imbalance and the onset of PE, but the mechanism is still unknown. And excessive outward migration may be its key factor, while the CXCL12 gradient may be chemotactic factors for DMSCs migration. Our previous researches show that hypoxia can lead to upregulation of DMSCs migration and activation of HIF-1α. It is known that HIF-1α can regulate CXCR4. Therefore, this project aims to first clear up the distribution of DMSCs and expression of CXCL12, HIF-1α and CXCR4. Then we investigate the effects of hypoxia on DMSCs migration and the expression of related signal molecules and functional proteins. The specific signaling pathways, through which CXCR4 regulates the functional proteins, are studied subsequently. Finally, the hypoxia induced PE model of rats are established and DMSCs are transfused back to verification the scientific hypothesis that HIF-1α/CXCR4 pathway regulates the hypoxia-induced excessive over migration and causes the maternal immune imbalance. This research will provide direct experimental evidences for using DMSCs for PE treatments.

子痫前期（PE）严重威胁孕产妇和胎儿生命安全，母体免疫失衡导致的系统性免疫-炎症反应是PE发病的中心环节。维持母体免疫平衡的蜕膜层间充质干细胞（DMSCs）数量不足是PE免疫失衡和发病的重要原因，但机制不明。DMSCs过度向外迁移可能是其关键因素，而CXCL12梯度可能是DMSCs迁移的趋化因素。本课题组预研显示缺氧可导致DMSCs迁移上调并激活HIF-1α，已知HIF-1α可调控CXCR4。因此，本项目拟先明确PE患者DMSCs的分布及CXCL12、HIF-1α、CXCR4的表达；随后探讨缺氧对DMSCs迁移以及相关信号分子和功能蛋白表达的影响；然后研究CXCR4调控功能蛋白表达的具体分子通路；最后构建缺氧诱导的PE样模型大鼠并回输DMSCs，验证“HIF-1α/CXCR4通路调控缺氧诱导DMSCs过度迁移，导致母体免疫失衡”的科学假设，为DMSCs用于PE治疗提供直接实验依据。

子痫前期（PE）严重威胁孕产妇和胎儿生命安全，母体免疫失衡导致的系统性免疫-炎症反应是PE发病的中心环节。维持母体免疫平衡的蜕膜层间充质干细胞（dMSCs）数量改变是PE免疫失衡和发病的重要原因，但机制不明。dMSCs迁移能力改变可能是其关键因素，而CXCL12梯度可能是dMSCs迁移的趋化因素。本项目首先明确PE患者和正常孕妇dMSCs的分布及CXCL12、HIF-1α、CXCR4的表达情况。选择14例PE患者和11例对照组，用Ⅱ型胶原酶消化法和贴壁法从蜕膜组织中提取dMSCs。采用ELISA和免疫组化方法检测血清和组织水平的CXCL12浓度。用Q-PCR和western印迹法检测CXCR4在dMSCs上的表达，用transwell法检测dMSCs的迁移能力。结果发现PE患者dMSCs中CXCR4和HIF-1α的表达明显高于对照组。PE患者的组织在蜕膜中CXCL12含量最高，其次是胎盘和脐带，而对照组的组织在脐带中CXCL2含量最高，其次是胎盘和蜕膜。CXCL12/CXCR4信号轴能介导dMSCs的迁移，并且在CXCL12诱导下，PE组dMSCs的迁移能力可能高于对照组的dMSCs。而dMSCs在缺氧状态下表现出迁移能力下降趋势。由此我们得出结论PE患者dMSCs可随CXCL12浓度梯度迁移到蜕膜层，可能在PE的发生发展中起一定作用。