MECHANISMS INVOLVED IN ASIATICOSIDE-INDUCED OSTEOGENIC DIFFERENTIATION IN HUMAN PERIODONTAL LIGAMENT CELLS

Abstract

Asiaticoside is an active compound isolated from Herb Centella asiatica (L.) Urban, which has been shown to induce osteogenic differentiation in human periodontal ligament (hPDL) cells. However, the mechanism of action of asiatioside remains poorly understood. The aim of this study was to investigate the mechanism involved in asiaticoside-induced osteogenic differentiation in hPDL cells. hPDL cells were treated with 10, 25, 50, 100 µM of asiaticoside and cell viability was tested by MTT assay. The mRNA expression levels were analyzed by using quantitative real-time PCR. Osteogenic differentiation was determined by alkaline phosphatase activity assay and alizarin red staining. The subcellular localization of β-catenin was demonstrated by immunofluorescence and western blot analysis. Data were analyzed using one-way analysis of variance (ANOVA) at p < 0.05. Asiaticoside did not influence the cell viability. Following asiaticoside stimulation, OSX, DSPP and DMP1 mRNA were significantly enhanced. ALP activity and mineralized nodule formation were also markedly induced. Interestingly, asiaticoside dose-dependently increased WNT3A, but not WNT5A and WNT10B. The activation of Wnt signaling was confirmed by the increase of nuclear β-catenin localization. Recombinant DKK1 could inhibit the Wnt signaling by blocking the translocation of β-catenin into the nucleus. Moreover, asiaticoside-induced osteoblastic gene expression was significantly diminished by DKK1. These results demonstrate that asiaticoside is likely involved in osteogenic differentiation by activating Wnt/β-catenin signaling pathway and as a potential agent to promote tissue regeneration in clinical application.