miR-143 suppresses the osteogenic differentiation of dental pulp stem cells by inactivation of NF-κB signaling pathway via targeting TNF-α

Background. Dental pulp stem cells (DPSCs) are multipotent and play an important role in repairing damaged and/or defective dentinogenesis/osteogenesis. Recent studies have documented the implication of miR-143 in osteogenic differentiation of DPSCs. Nevertheless, the detailed mechanisms of miR-143 involved in the osteogenic differentiation of DPSCs remain to be further elaborated. Methods: Isolated DPSCs were incubated with osteogenic differentiation medium to induce osteogenic differentiation. qRT-PCR and western blot were performed to determine the expressions of miR-143 and tumor necrosis factor a (TNF-alpha). Luciferase reporter assay was used to confirm whether TNF-alpha was a target of miR-143. Osteogenic differentiation of DPSCs was evaluated by alkaline phosphatase (ALP) activity assay, ALP staining, and western blot analyses of osteogenic-markers including bone morphogenetic protein 2 (BMP2), ALP, runt related transcription factor 2 (RUNX2) and collagen type 1 (COLI). Results: miR-143 was downregulated and TNF-alpha was upregulated during osteogenic differentiation of DPSCs. miR-143 posttranscriptionally regulated TNF-alpha expression in DPSCs by binding to its 3'UTR. miR-143 over expression suppressed osteogenic differentiation of DPSCs, as demonstrated by the decrease of ALP activity, ALP positive cell ratio, as well as BMP2, ALP, RUNX2, and COLI expressions. Moreover, miR-143 reversed TNF-alpha-induced osteogenic differentiation of DPSCs. Finally, the osteogenic differentiation of DPSCs induced by miR-143 inhibitor was attenuated following inactivation of nuclear factor kappa B (NF-kappa B) signaling pathway. Conclusion: miR-143 suppressed the osteogenic differentiation of DPSCs by blockade of NF-kappa B signaling pathway via targeting TNF-alpha.