Downregulation of LINC00707 promotes osteogenic differentiation of human bone marrow-derived mesenchymal stem cells by regulating DKK1 via targeting miR-103a-3p

Human bone marrow-derived mesenchymal stem cells (HBMSCs) have the potential of multidirectional differentiation and self-renewal, which is important for the formation of human bone. It has been reported that long non-coding RNAs (lncRNAs) serve important roles in HBMSC osteogenic differentiation. The current study aimed to investigate the roles of long intergenic non-protein coding RNA 00707 (LINC00707) and microRNA (miR)-103a-3p in the osteogenic differentiation of HBMSCs. Reverse transcription-quantitative PCR (RT-qPCR) was performed to detect the expression levels of LINC00707, miR-103a-3p and osteogenesis-related genes (Alkaline phosphatase, osteocalcin, osteopontin and RUNX family transcription factor 2) in HBMSCs cultured in proliferation medium (PM) and osteogenic medium (OM). Mineralized matrix deposition was measured using Alizarin Red S staining. The protein expression levels of osteogenesis-related genes were detected by western blotting. The relationships between LINC00707, miR-103a-3p and dickkopf WNT signaling pathway inhibitor 1 (DKK1) were predicted using Starbase and TargetScan7.2, and were further assessed with a dual-luciferase reporter assay. After 21 days of cell culture, the results indicated that expression of LINC00707 was downregulated, and those of miR-103a-3p and osteogenesis-related genes were upregulated in OM-cultured HBMSCs. However, there was no significant difference in the aforementioned gene expression levels in PM-cultured HBMSCs. Small interfering (si)LINC00707 increased the deposition of mineralized matrix and promoted the expression levels of osteogenesis-related proteins. Furthermore, miR-103a-3p was predicted to be a target gene of LINC00707, its expression was significantly upregulated by siLINC00707, while overexpression of miR-103a-3p increased the expression levels of osteogenesis-related proteins. DKK1 was also predicted to be a target gene of miR-103a-3p and could inhibit the expression levels of osteogenesis-related proteins, but such effect of DKK1 could be reversed by the miR-103a-3p mimic. In conclusion, the present results suggested that LINC00707 regulated DKK1 expression by targeting miR-103a-3p to regulate osteogenic differentiation.