Estrogen regulates osteogenic differentiation of human periodontal ligament stem cells via Wnt/beta-catenin signaling pathway / 中国组织工程研究

ABSTRACT

BACKGROUND: Estrogen can promote the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs), but the molecular mechanism is unclear. OBJECTIVE:To study the regulatory effect of estrogen on the osteogenic differentiation of hPDLSCs via Wnt/β-catenin signaling pathway. METHODS: The hPDLSCs were isolated and purified by digestion method combined with limited dilution clone method. Three experimental groups were set as follows osteogenic induction only (control group); 1×10-7mol/L estrogen with osteogenic induction (estrogen group); and 100 μg/L Wnt3a protein with osteogenic induction (Wnt3a group). Alkaline phosphatase activity was detected at 1, 3, 5, 7 days of osteogenic induction. Western blot was used to detect the expression of Wnt/β-catenin signaling pathway related proteins β-catenin, P-GSK-3β, GSK-3β, CyclinD1 and osteoblast-related proteins Runx2 and OCN after 7 days of osteogenic induction. RESULTS AND CONCLUSION: The activity of ALP in all groups increased with time. The expression level of ALP in the estrogen group and Wnt3a group was higher than that in the control group at 1, 3, 5 and 7 days of induction (P < 0.05), while there was no significant difference between the former two groups (P > 0.05). The western blot results showed that the expression levels of β-catenin, P-GSK-3β, CyclinD1, Runx2 and OCN in the estrogen group and Wnt3a group were higher than those in the control group (P < 0.05), while the expression of GSK-3β was lower than that in the control group (P < 0.05). But there were no differences in the expression of Wnt/β-catenin signaling pathway related proteins and mid-late osteogenic markers between estrogen group and Wnt3a group (P > 0.05). To conclude, estrogen can enhance the osteogenic differentiation of hPDLSCs, and the underlying mechanism is likely to activate the Wnt/β-catenin signaling pathway in activated hPDLSCs exposed to estrogen.