Department of Gynaecology and Obstetrics, The Second Hospital of Jilin University, Changchun 130041, PR China.
Department of Rehabilitation, The Second Hospital of Jilin University, Changchun 130041, PR China.
Sci Total Environ. 2020 Nov 25;745:139919. doi: 10.1016/j.scitotenv.2020.139919. Epub 2020 Jun 3.
Dysregulation of the MicroRNA (miR) Let-7 family has been implicated in preeclampsia (PE). Abnormal trophoblast cell proliferation and apoptosis associate with the pathogenesis of PE. The present study was designed to test the hypothesis whether let-7a could regulate the biological functions of trophoblasts and explore the mechanism how it works in the development of early-onset severe PE. The putative target genes Bcl-xl and YAP1 of let-7a were verified by luciferase assay. The roles of let-7a, Bcl-xl and YAP1 in regulating JEG-3 cell functions were examined by altering their expression with mimic, overexpression plasmids or siRNAs. The methylation status of let-7a-3 in PE was assessed by methylation-specific and bisulfite sequencing PCR assays. JEG-3 cells were treated with DNA methyltransferase inhibitor to analyze whether let-7a-3 demethylation functioned in PE. Tumor growth and cell apoptosis were measured from nude mice inoculated with JEG-3 cells overexpressing let-7a. The results revealed let-7a was highly expressed in early-onset severe PE and let-7a-3 presented a low methylation level. Functionally, let-7a upregulation could inhibit the viability and cell cycle progression but induce the apoptosis of JEG-3 cells. Bcl-xl and YAP1, target genes of let-7a, could rescue cell apoptosis induced by let-7a. The demethylation of let-7a-3 was also observed to elevate the expression of let-7a and enhance JEG-3 cell apoptosis. Let-7a inhibited tumorigenic ability of JEG-3 cells and enhanced cell apoptosis in vivo. Altogether, let-7a could enhance cell apoptosis in trophoblasts through downregulation of Bcl-xl and YAP1, which suggests that let-7a might be a key regulator in the progression of PE.
miR 家族的 Let-7 失调与先兆子痫（PE）有关。异常的滋养细胞增殖和凋亡与 PE 的发病机制有关。本研究旨在检验假设，即 let-7a 是否可以调节滋养细胞的生物学功能，并探讨其在早发型重度 PE 发病机制中的作用机制。通过荧光素酶测定验证了 let-7a 的假定靶基因 Bcl-xl 和 YAP1。通过改变 mimic、过表达质粒或 siRNA 来改变其表达，研究了 let-7a、Bcl-xl 和 YAP1 在调节 JEG-3 细胞功能中的作用。通过甲基化特异性和亚硫酸氢盐测序 PCR 测定评估了 PE 中 let-7a-3 的甲基化状态。用 DNA 甲基转移酶抑制剂处理 JEG-3 细胞，分析 let-7a-3 去甲基化是否在 PE 中起作用。用接种过表达 let-7a 的 JEG-3 细胞的裸鼠测量肿瘤生长和细胞凋亡。结果表明，let-7a 在早发型重度 PE 中高表达，let-7a-3 呈现低甲基化水平。功能上，let-7a 的上调可以抑制 JEG-3 细胞的活力和细胞周期进程，但诱导其凋亡。let-7a 的靶基因 Bcl-xl 和 YAP1 可以挽救 let-7a 诱导的细胞凋亡。还观察到 let-7a-3 的去甲基化可提高 let-7a 的表达并增强 JEG-3 细胞的凋亡。let-7a 抑制 JEG-3 细胞的致瘤能力并增强体内细胞凋亡。总之，let-7a 通过下调 Bcl-xl 和 YAP1 增强滋养细胞的细胞凋亡，这表明 let-7a 可能是 PE 进展的关键调节因子。
