miR-342-3p elevates osteogenic differentiation of umbilical cord mesenchymal stem cells via inhibiting Sufu in vitro.

Human umbilical mesenchymal stem cells (UCMSCs) have been wildly used in tissue engineering field as a promising source because of their unlimited and noninvasive origin. To selectively induce osteogenic differentiation of UCMSCs, it's imperative to understand the regulatory molecular mechanism underlying the process of how these cells switch into osteogenic lineage path. We previously showed enhanced sonic hedgehog (Shh) signaling pathway upon osteogenic induction in mesenchymal stem cells. In this study, miRNA-seq analysis revealed substantial Shh-dependent expression of distinct miRNAs, including miR-342-3p, during ostogenesis. RT-qPCR confirmed that miR-342-3p was increased at a greater level when Shh signaling pathway was activated by N-terminal of Shh ligand compared with osteogenic induction alone, in contrast to the decreasing of suppressor-of-fused protein (Sufu). Consistently, transient overexpressing miR342-3p in UCMSCs via miR-342-3p mimics dramatically decreased Sufu, a suppressor of Gli, while osteogenic markers, including alkaline phosphate and osteocalcin, were upregulated during osteogenic induction, indicating that miR-342-3p might be involved in osteogenesis through the Shh signaling pathway. In conclusion, this study showed the potential of miR-342-3p as a therapeutic target to promote bone regeneration by modulating expression of Sufu in UCMSCs.