Estrogen Enhances Osteogenic Differentiation of Human Periodontal Ligament Stem Cells by Activating the Wnt/β-Catenin Signaling Pathway

Objectives:This study was designed to investigate the role of the Wnt/beta-catenin signaling pathway in estrogen-enhanced osteogenic differentiation of human peridontal ligament stem cells (hPLSCs).Methods:The limiting dilution technique was used for cloning and purification of hPLSCs. Flow cytometric analysis of STRO-1, CD146, and CD45 was conducted to identify hPLSCs. The P3 hPDLSCs were divided into 4 groups: Control, 10(-7)M E2, 10(-7)M E2+100 ng/mL Wnt3a, 10(-7)M E2+5x10(-3)M Xav939. After 7 days of osteogenic induction, qRT-PCR was used to detect the mRNA expression of beta-catenin, CyclinD1, alkaline phosphatase, Runx2, and OCN; Western blot was used to detect the protein expression of beta-catenin, GSK3 beta, P-GSK3 beta, CyclinD1, Runx2, and OCN; After 1, 3, 5, 7 days of osteogenic induction, the activity of alkaline phosphatase was detected.Results:The authors' results showed that E2 was able to enhance the osteogenic differentiation of hPDLSCs and Wnt/beta-catenin signaling pathway was involved. Wnt3a activated the signaling pathway of Wnt/beta-catenin and further enhanced the osteogenesis of hPDLSCs. Xav939 inhibited the Wnt/beta-catenin signaling pathway in estrogen-mediated environment, but did not obviously inhibit the osteogenic differentiation of hPDLSCs.Conclusions:E2 enhanced osteogenic differentiation of hPDLSCs through the activation of the Wnt/beta-catenin signaling pathway.