雌激素介导下Wnt/β-catenin信号通路调控人牙周膜干细胞的成骨分化

摘要

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.%背景:已有实验发现,雌激素能促进人牙周膜干细胞骨向分化,但雌激素调控人牙周膜干细胞成骨分化的具体机制目前尚未明确.目的:探讨雌激素通过Wnt/β-catenin信号通路对人牙周膜干细胞骨向分化的调控作用.方法:采用消化组织块法联合有限稀释克隆法分离培养并纯化得到人牙周膜干细胞,取第3代人牙周膜干细胞随机分为3组:单纯成骨诱导液组(对照组);含1×10-7 mol/L雌激素成骨诱导液组(雌激素组);含100 μg/L Wnt3a成骨诱导液组(Wnt3a组).各组在成骨诱导1,3,5,7 d时检测碱性磷酸酶活性,成骨诱导7 d时采用Western blot检测Wnt/β-catenin信号通路相关蛋白β-catenin、GSK-3β、P-GSK-3β、CyclinD1以及成骨相关蛋白Runx-2、OCN的表达水平.结果与结论:①各组碱性磷酸酶活性随时间推移均呈上升趋势.雌激素组和 Wnt3a 组在诱导1,3,5,7 d各时间点碱性磷酸酶表达水平均高于对照组(P < 0.05);而雌激素组和Wnt3a组表达水平差异无显著性意义(P > 0.05);②雌激素组和Wnt3a组β-catenin、P-GSK-3β、CyclinD1的表达水平高于对照组(P < 0.05),而GSK-3β表达水平低于对照组(P < 0.05),同时雌激素组和Wnt3a组的成骨中晚期标志物Runx2、OCN表达水平均高于对照组(P < 0.05).雌激素组和Wnt3a组间Wnt/β-catenin信号通路相关因子和成骨中晚期相关蛋白的表达差异无显著性意义(P > 0.05);③结果表明,雌激素可促进人牙周膜干细胞的成骨分化,这种促进作用的实现可能与雌激素微环境下活化人牙周膜干细胞中的Wnt/β-catenin信号通路有关.