Asiaticoside induces osteogenic differentiation of human periodontal ligament cells through the Wnt pathway.

Asiaticoside is a compound isolated from Herb Centella asiatica, which has been shown to promote osteogenic differentiation of human periodontal ligament (hPDL) cells. This study investigated the molecular mechanism underlying the asiaticoside-induced osteogenic differentiation of hPDL cells. hPDL cells were incubated with various concentrations of asiaticoside to test cell viability by MTT assay. The mRNA expression levels were analyzed by using quantitative real-time polymerase chain reaction (PCR). Osteogenic differentiation was determined by alkaline phosphatase activity assay and alizarin red staining. The subcellular localization of β-catenin was analyzed by both immunofluorescence and western blot. The results showed that asiaticoside had no effect on the cell viability at any of the tested concentrations. Real-time PCR revealed that osterix (OSX) and dentin matrix protein1 (DMP1) mRNA were significantly enhanced by asiaticoside treatment. Alkaline phosphatase activity and in vitro mineralization were also significantly induced. Interestingly, asiaticoside dose-dependently increased WNT3A mRNA expression, but not WNT5A and WNT10B. The activation of Wnt signaling was shown to result in nuclear accumulation of β-catenin as evaluated by immunofluorescence staining and western blot analysis. Pre-treatment with recombinant human Dickkopf1 (rhDKK1) inhibited asiaticoside-induced β-catenin nuclear translocation and osteoblast marker gene expression. Moreover, rhDKK1 attenuated asiaticoside-induced DMP1 protein expression. The data demonstrate that asiaticoside induces osteogenic differentiation of hPDL cells by activating the Wnt/β-catenin signaling pathway. The findings suggest that asiaticoside could be used as a novel therapeutic drug for periodontal tissue regeneration.