Preeclampsia (PE) is a frequently occurring pregnancy disorder in the placenta, which results in various maternal and fetal complications. The current study aims to evaluate the role of extracellular vesicles (EVs)-encapsulated microRNA (miR)-101 in biological processes of trophoblasts in PE and its underlying mechanism. Human umbilical cord mesenchymal stem cell (HUCMSC) and HUCMSC-derived EVs were isolated and cultured, after which EV characterization was carried out using PKH67 staining. In silico analyses were adopted to predict the downstream target genes of miR-101, and dual luciferase reporter gene assay was applied to validate the binding affinity. Furthermore, loss- and gain-of-function approaches were adopted to determine the role of miR-101 and bromodomain-containing protein 4 (BRD4) in trophoblast proliferation and invasion using EDU staining and transwell assay. In addition, a rat model of PE was established to verify the function of EV-encapsulated miR-101 in vivo. Placental tissues obtained from PE patients presented with downregulated miR-101 expression and upregulated BRD4 and CXCL11 expression. EV-encapsulated miR-101 from HUCMSCs could be delivered into the trophoblast HTR-8/SVneo cells, thus enhancing proliferation and migration of trophoblasts. Mechanically, miR-101 targeted and negatively regulated BRD4 expression. BRD4 knockdown promoted the proliferation and migration of trophoblasts by suppressing NF-κB/CXCL11 axis. EV-encapsulated miR-101 from HUCMSCs also reduced blood pressure and 24 h urine protein in vivo, thereby ameliorating PE. In summary, EV-encapsulated miR-101 promoted proliferation and migration of placental trophoblasts through the inhibition of BRD4 expression via NF-κB/CXCL11 inactivation.

中文翻译：

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含有 MiR-101 的细胞外囊泡与 BRD4 结合并增强先兆子痫中滋养层的增殖和迁移。

先兆子痫 (PE) 是胎盘中常见的妊娠疾病，可导致各种母婴并发症。本研究旨在评估细胞外囊泡 (EVs) 包裹的 microRNA (miR)-101 在 PE 滋养细胞生物学过程中的作用及其潜在机制。分离和培养人脐带间充质干细胞 (HUCMSC) 和 HUCMSC 衍生的 EV，然后使用 PKH67 染色进行 EV 表征。采用计算机分析预测miR-101的下游靶基因，并应用双荧光素酶报告基因测定验证结合亲和力。此外，使用 EDU 染色和 transwell 测定，采用功能丧失和获得的方法来确定 miR-101 和含溴结构域蛋白 4 (BRD4) 在滋养层增殖和侵袭中的作用。此外，还建立了PE大鼠模型，以验证EV包裹的miR-101在体内的功能。从 PE 患者获得的胎盘组织呈现出下调的 miR-101 表达和上调的 BRD4 和 CXCL11 表达。来自 HUCMSCs 的 EV 包裹的 miR-101 可以被递送到滋养层 HTR-8/SVneo 细胞中，从而增强滋养层的增殖和迁移。机械地，miR-101 靶向并负调节 BRD4 表达。BRD4 敲低通过抑制 NF-κB/CXCL11 轴促进滋养细胞的增殖和迁移。来自 HUCMSCs 的 EV 封装的 miR-101 在体内也降低了血压和 24 小时尿蛋白，从而改善了 PE。总之，EV 包裹的 miR-101 通过 NF-κB/CXCL11 失活抑制 BRD4 的表达来促进胎盘滋养细胞的增殖和迁移。