Osteogenic differentiation is an important process of new bone formation, miR-409-3p has been reported to be upregulated in osteogenic differentiation of human bone marrow mesenchymal stem cells (MSCs). To investigate the regulatory effect of miR-409-3p on osteogenic differentiation of MSCs and its molecular mechanism, the expression of miR-409-3p in osteoblast (HCO) and bone marrow-derived MSCs (MSC-A, MSC-B, MSC-U) were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The binding of miR-409-3p to SCAI in MSC-B was investigated by dual-luciferase reporter gene assay. MSC-B were selected to transfect with miR-409-3p analog/complementary sequence (cs), miR-409-3p analog + SCAI and miR-409-3p cs + small interfering (si)-SCAI, as well as control, respectively. The alkaline phosphatase activity, alizarin red staining, and the expression of osteogenic markers in MSC-B during osteoblastic differentiation were tested by RT-qPCR and Western blotting, respectively. The Wnt/β-catenin pathway was inhibited by dickkopf-related protein 1 to get the roles of miR-409-3p during the osteoblastic differentiation of MSC-B when transfected with miR-409-3p analog. The expression of miR-409-3p in HCO was higher than that in these three MSCs, showing an increasing time-dependent trend on the 0 and 21th day of osteoblastic differentiation. MiR-409-3p directly regulated SCAI by targeting SCAI 3'UTR. Further, miR-409-3p suppressed SCAI expression, but SCAI upregulation suppressed the osteoblastic differentiation, as well as reduced the relative mRNA/protein expression of Wnt/β-catenin signaling pathway-related genes. Importantly, disruption of Wnt signaling also blocked miR-409-3p induced osteoblastic differentiation of MSCs. Therefore, miR-409-3p promotes osteoblastic differentiation through the activation of the Wnt/β-catenin pathway by downregulating SCAI expression.

中文翻译：

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MicroRNA-409-3p 通过靶向 SCAI 激活 Wnt/β-catenin 信号通路促进成骨细胞分化。

成骨分化是新骨形成的重要过程，据报道 miR-409-3p 在人骨髓间充质干细胞 (MSC) 的成骨分化中上调。探讨miR-409-3p对MSCs成骨分化的调控作用及其分子机制，miR-409-3p在成骨细胞（HCO）和骨髓来源的MSCs（MSC-A、MSC-B、MSCs）中的表达-U) 通过逆转录-定量聚合酶链反应 (RT-qPCR) 检测。通过双荧光素酶报告基因测定研究了 miR-409-3p 与 MSC-B 中 SCAI 的结合。选择 MSC-B 转染 miR-409-3p 类似物/互补序列 (cs)、miR-409-3p 类似物 + SCAI 和 miR-409-3p cs + 小干扰 (si)-SCAI，以及对照，分别。碱性磷酸酶活性，茜素红染色，分别通过RT-qPCR和Western印迹检测成骨细胞分化过程中MSC-B中成骨标志物的表达。当用 miR-409-3p 类似物转染时，Wnt/β-catenin 通路被 dickkopf 相关蛋白 1 抑制以获得 miR-409-3p 在 MSC-B 成骨细胞分化过程中的作用。miR-409-3p在HCO中的表达高于这三种MSC，在成骨细胞分化的第0天和第21天呈时间依赖性增加的趋势。MiR-409-3p 通过靶向 SCAI 3'UTR 直接调节 SCAI。此外，miR-409-3p 抑制 SCAI 表达，但 SCAI 上调抑制成骨细胞分化，并降低 Wnt/β-catenin 信号通路相关基因的相对 mRNA/蛋白质表达。重要的，Wnt 信号的破坏也阻止了 miR-409-3p 诱导的 MSCs 的成骨细胞分化。因此，miR-409-3p通过下调SCAI表达，激活Wnt/β-catenin通路促进成骨细胞分化。