microRNA-135a-5p通过β-TrCP调控滋养细胞EMT参与子痫前期发病的机制研究

The exact pathogenesis of preeclampsia (PE) remains uncertain. According to the Two-stage Model theory, PE is associated with insufficient trophoblast invasion. The epithelial-mesenchymal transition (EMT) is closely associated with trophoblast invasion, but the under mechanism remains largely unclear. β-TrCP, an E3 ubiquitin ligase of the SCF family in ubiquitin-proteasome system (UPS), regulates various cellular processes，such as apoptosis, proliferation and invasion. Our previous studies showed that β-TrCP was up-regulated in preeclamptic placentas. Further, β-TrCP was related to trophoblast EMT and invasion. We also found that miR-135a-5p, which is predicted to target β-TrCP gene, was decreased in preeclamptic placentas. We hypothesize that miR-135a-5p targets β-TrCP, which regulates trophoblast EMT and invasion through UPS, and plays an important role in the pathogenesis of PE. Our study will include placenta samples examination, trophoblast cells and β-TrCP over-expressed pregnant mice experiments. In this project, we are going to investigate the molecular mechanism of PE through miR-135a-5p/β-TrCP/ ubiquitin-proteasome pathway. Our results will provide a new way for prevention and treatment of preeclampsia.

子痫前期发病机制不明，“二阶段模型”理论认为与胎盘滋养细胞侵袭功能障碍密切相关。文献报道上皮间质转化（EMT）使滋养细胞获得侵袭力，但其调控机制不详。β-TrCP是泛素-蛋白酶体系统（UPS）SCF类泛素连接酶E3的核心蛋白，介导UPS参与调控细胞凋亡、增殖和侵袭等。我们前期研究发现β-TrCP在子痫前期胎盘高表达，并且可能与滋养细胞EMT及侵袭力相关。β-TrCP是预测的miR-135a-5p靶基因之一，我们还发现子痫前期胎盘miR-135a-5p表达下调。我们推测：miR-135a-5p靶向作用于β-TrCP，介导UPS调控滋养细胞EMT，从而调控滋养细胞侵袭、迁移，最终参与子痫前期的发病。本项目拟结合临床样本、滋养细胞体系和β-TrCP过表达孕鼠模型，探讨miR-135a-5p/β-TrCP介导泛素-蛋白酶体途径参与子痫前期发病的分子机制，研究结果可能为子痫前期的防治提供新的切入点。

子痫前期发病机制不明，目前研究认为与胎盘滋养细胞侵袭功能障碍密切相关，而上皮间质转化（EMT）使滋养细胞获得侵袭力，但其调控机制不详。本项目主要研究内容如下：①临床实验：收集子痫前期和相近孕周的正常孕妇的胎盘，分析 miR-135a-5p 和 β-TrCP的表达与子痫前期的关系；同时比较正常胎盘和子痫前期胎盘滋养细胞 EMT 状态。②细胞实验：采用 HTR-8/SVneo 和 TEV-1 两株绒毛外滋养细胞系，阐明miR-135a-5p 通过 β-TrCP 介导泛素-蛋白酶体途径作用于底物 Snail，调控滋养细胞 EMT 以及侵袭、迁移的分子机制。③动物实验：建立β-catenin泛素化降解增强剂NRX-252262 过表达孕鼠模型，比较实验组和对照组孕鼠血压以及 EMT 标记分子的表达。主要研究结果如下：在子痫前期胎盘上，miR-135a-5p表达下调， β-TrCP的表达上调；miR-135a-5p靶向作用于β-TrCP，β-TrCP通过泛素-蛋白酶体途径作用于底物 Snail，调控滋养细胞 EMT 以及侵袭、迁移；并且在β-catenin泛素化降解增强剂NRX-252262 过表达孕鼠模型中，小鼠胎盘EMT被抑制。本研究的结果提示：miR-135a-5p表达下调，导致 β-TrCP的表达上调，后者通过泛素-蛋白酶体途径作用于底物 Snail，抑制滋养细胞 EMT 以及侵袭、迁移，从而参与子痫前期的发病过程。研究结果可能为子痫前期的防治提供新的切入点。