Department of General Dentistry and Emergency, School of Stomatology, Fourth Military Medical University, Xi'an, PR China.
Cells Tissues Organs. 2012;195(5):400-13. doi: 10.1159/000328003. Epub 2011 Aug 10.
Mechanical stimulation and estrogen have been proven to be two important factors in promoting mesenchymal stem cell activity, which is closely associated with bone formation, mass maintenance and remodeling. However, the superposition effects of mechanical stimulation and estrogen on stem cells remain unknown. It is also unclear if the estrogen receptor (ER) plays only a key role in estrogen signaling or if it is also involved in the mechanotransduction of stem cells. To investigate the role of estrogen and its receptors in the mechanobiological effects in bone mesenchymal stem cells (BMSCs), isolated mesenchymal stem cells from bone marrow were exposed to mechanical pressure under additional estrogen treatment or ER blockade. Cell proliferation was examined using an MTT assay and alkaline phosphatase (ALP) activity was determined by a modified enzyme kinetic method. Alignment of the cytoskeleton was observed by Coomassie brilliant blue staining and F-actin fluorescent staining. Cellular ultrastructure was observed under transmission electron microscope. Expression of ERα was investigated using Western blot analysis. Results indicated that mechanical pressure promoted cell proliferation, ALP activity, ERα expression and F-actin stress fiber formation. Overall, this effect was enhanced by the addition of estrogen and inhibited by ER blockade. We concluded that pressure stimulated proliferation and differentiation capability via F-actin transduction in BMSCs. The effects were enhanced by the addition of estrogen, and the ER plays an important role in regulating mechanobiological effects and the mechanotransduction processes of BMSCs.
机械刺激和雌激素已被证明是促进间充质干细胞活性的两个重要因素，而细胞活性与骨形成、质量维持和重塑密切相关。然而，机械刺激和雌激素对干细胞的叠加效应尚不清楚。雌激素受体 (ER) 是否仅在雌激素信号转导中发挥关键作用，还是也参与干细胞的机械转导，目前也尚不清楚。为了研究雌激素及其受体在骨髓间充质干细胞 (BMSCs) 的力学生物学效应中的作用，从骨髓中分离出间充质干细胞，在施加额外的雌激素处理或 ER 阻断的情况下，暴露于机械压力下。使用 MTT 分析检查细胞增殖，通过改良酶动力学方法确定碱性磷酸酶 (ALP) 活性。通过考马斯亮蓝染色和 F-actin 荧光染色观察细胞骨架的排列。在透射电子显微镜下观察细胞超微结构。使用 Western blot 分析研究 ERα 的表达。结果表明，机械压力促进细胞增殖、ALP 活性、ERα 表达和 F-actin 应力纤维形成。总的来说，这种作用通过添加雌激素而增强，并被 ER 阻断所抑制。我们得出结论，压力通过 BMSCs 中的 F-actin 转导刺激增殖和分化能力。雌激素的添加增强了这种作用，而 ER 在调节 BMSCs 的力学生物学效应和机械转导过程中起着重要作用。
