MicroRNA-127-3p inhibits the in vitro osteogenic differentiation of bone marrow-derived mesenchymal stromal cells

MicroRNAs (miRNAs) are small non-coding RNAs that play a crucial role in post-transcriptional gene regulation. They are key regulators in various biological processes, including skeletal development and homeostasis. Disruptions in osteogenic differentiation pathways can lead to skeletal disorders such as osteoporosis and delayed fracture healing. MiR-127, initially identified for its tumor suppressor functions, has been already associated with skeletal disorders, but its direct role in regulating osteogenesis is still not fully understood. In this study, we demonstrated that overexpression of miR-127-3p using a miRNA mimics, significantly inhibits the in vitro osteogenesis of human bone marrow-derived mesenchymal stromal cells (hBMSCs). We observed reduced alkaline phosphatase activity and mineralization, along with decreased expression of bone marker genes. Additionally, pathway enrichment analysis from RNA sequencing at day 7 of osteogenesis indicated downregulation of cell cycle- and proliferation-related processes, which was confirmed by an BrdU incorporation assay. Also, upregulation of inflammation- and cell adhesion-related pathways was observed, and we were able to confirm the upregulation of Notch pathway by RT-qPCR. In conclusion, miR-127-5p inhibits the osteogenic differentiation and mineralization of hBMSCs.