miR‐20a‐5p regulated SMAD6 to inhibit chondrogenesis of hDPSCs

Objectives Chondrogenic differentiation of human dental pulp stem cells (hDPSCs) is highly promising for cartilage repair. The specific mechanism, however, still needs to be explicated. Materials and Methods In this study, we isolated hDPSCs and transfected cells with lentiviruses containing an over-expression, knock-down, or negative control of miR-20a-5p. Three-D pellet cultures of hDPSCs were used for the chondrogenic induction. Following the pellet culture period, chondrogenesis was assessed by histological and immunohistochemical analysis and expression of chondrogenic-related genes. Dual-luciferase report assay was performed to determine potential targeted genes of miR-20a-5p, and the phosphorylation levels of P65 and I kappa B alpha were explored. Animal experiments were performed to determine the effect of miR-20a-5p on cartilage regeneration. Results miR-20a-5p was showed to repress the expression of SMAD6 to inhibit the chondrogenic differentiation of hDPSCs. Accordingly, the knock-down of miR-20a-5p promoted cartilage regeneration in the osteochondral defects of rats. Mechanically, it is indicated that NF-kappa B signaling is the potential down-stream network of miR-20a-5p/Smad6 crosstalk during chondrogenic differentiation. Conclusions miR-20a-5p could target SMAD6 to activate NF-kappa B signaling pathway, and thus inhibit chondrogenesis of hDPSCs, which provided promising therapeutic target for cartilage defects clinically.