Department of Obstetrics and Gynecology, Hebei Medical University, Shijiazhuang, Hebei 050000, P.R. China.
Reproductive Medicine Center, The Fourth Hospital of Shijiazhuang Affiliated to Hebei Medical University, Shijiazhuang, Hebei 050000, P.R. China.
Int J Mol Med. 2022 Oct;50(4). doi: 10.3892/ijmm.2022.5179. Epub 2022 Aug 12.
Successful embryo implantation requires a competent embryo, a receptive endometrium and synchronized communication between them. The selection of embryos with the highest implantation potential remains a challenge in the field of assisted reproductive technology. Moreover, little is known about the precise molecular mechanisms underlying embryo‑endometrium crosstalk. MicroRNAs (miRNAs/miRs) have been detected in the spent embryo culture medium (SCM); however, their functions at the preimplantation stage remain unclear. In the present study, human SCM samples were collected during fertilization/intracytoplasmic sperm injection‑embryo transfer and divided into implanted and not‑implanted groups according to the clinical pregnancy outcomes. Total RNA was extracted and six miRNAs (miR‑372‑3p, miR‑373‑3p, miR‑516b‑5p, miR‑517a‑3p, miR‑519d‑3p and miR‑520a‑3p) were selected for reverse transcription‑quantitative PCR (RT‑qPCR) analysis. The results revealed that miR‑372‑3p and miR‑519d‑3p were markedly increased in SCM from blastocysts that failed to implant compared with in blastocysts that implanted. The receiver operating characteristic curve analysis revealed that miR‑519d‑3p was superior to miR‑372‑3p in predicting pregnancy outcomes. miRNA uptake and cell adhesion assays were performed to determine whether miR‑519d‑3p could be taken up by endometrial epithelial cells and to examine the biological roles of miR‑519d‑3p after internalization. Potential targets of miR‑519d‑3p were verified using a dual‑luciferase reporter system. The results demonstrated that miR‑519d‑3p was taken up by human endometrial epithelial cells and that it may inhibit embryo adhesion by targeting HIF1α. Using RT‑qPCR, western blot analysis and flow cytometry assay, HIF1α was shown to inhibit the biosynthesis of fucosyltransferase 7 and sialyl‑Lewis X (sLe), a cell‑surface oligosaccharide that serves an important role in embryonic apposition and adhesion. In addition, a mouse model was established and the results suggested that miR‑519d‑3p overexpression hampered embryo implantation . Taken together, miRNAs in SCM may serve as novel biomarkers for embryo quality. Furthermore, miR‑519d‑3p was shown to mediate embryo‑endometrium crosstalk and to negatively regulate embryo implantation by targeting HIF1α/FUT7/sLe pathway.
胚胎着床的成功需要一个有能力的胚胎、一个有接受能力的子宫内膜和它们之间的同步通讯。选择具有最高着床潜力的胚胎仍然是辅助生殖技术领域的一个挑战。此外，关于胚胎-子宫内膜相互作用的确切分子机制知之甚少。已经在废弃的胚胎培养液（SCM）中检测到 microRNAs（miRNAs/miRs）；然而，它们在着床前阶段的功能尚不清楚。在本研究中，在受精/卵胞浆内单精子注射-胚胎移植期间收集人 SCM 样本，并根据临床妊娠结果将其分为着床组和未着床组。提取总 RNA，并对六种 miRNA（miR-372-3p、miR-373-3p、miR-516b-5p、miR-517a-3p、miR-519d-3p 和 miR-520a-3p）进行逆转录-定量 PCR（RT-qPCR）分析。结果显示，与着床的囊胚相比，未能着床的囊胚的 SCM 中 miR-372-3p 和 miR-519d-3p 明显增加。受试者工作特征曲线分析显示，miR-519d-3p 在预测妊娠结局方面优于 miR-372-3p。miRNA 摄取和细胞黏附实验用于确定 miR-519d-3p 是否可被子宫内膜上皮细胞摄取，并研究内化后 miR-519d-3p 的生物学作用。使用双荧光素酶报告系统验证 miR-519d-3p 的潜在靶标。结果表明，miR-519d-3p 被人子宫内膜上皮细胞摄取，并且可能通过靶向 HIF1α 抑制胚胎黏附。通过 RT-qPCR、western blot 分析和流式细胞术分析，表明 HIF1α 抑制岩藻糖基转移酶 7 和唾液酸化路易斯 X（sLe）的生物合成，sLe 是一种在胚胎贴附和黏附中起重要作用的细胞表面寡糖。此外，建立了小鼠模型，结果表明 miR-519d-3p 过表达阻碍了胚胎着床。综上所述，SCM 中的 miRNAs 可能作为胚胎质量的新型生物标志物。此外，miR-519d-3p 通过靶向 HIF1α/FUT7/sLe 通路调节胚胎-子宫内膜相互作用，负向调节胚胎着床。
