Abstract: Objective: To study the role of erythropoietin (EPO) on osteoblast differentiation through ephrinB2/EphB4 signaling, and explore the mechanism of EPO in bone homeostasis. Methods: Mouse bone marrow stromal cell line (ST2) was cultured in vitro. After treated by EPO, the expression of EphB4 and osteoblastic related genes were examined by real-time PCR. The differentiation and function of osteoblasts were observed by ALP activity and alizarin red staining. Co-culture of osteoclast and osteoblast was mimicked by adding ephrinB2-Fc to the culture of ST2 cells, which activated ephrinB2-EphB4 forward signal. Differentiation and function of osteoblasts were measured by the above methods. The expression of EphB4 was knocked down using RNAi. The effect of EPO on osteoblast was also tested. Results: EPO could increase the expression of osteoblastic related genes such as RUNX2, ALP and Col1. Expression of EphB4 was also increased. ALP activities and calcium nodules were increased. In the mimicking co-culture system, EPO could promote the differentiation and function of ST2 cells. The effect of EPO on ST2 cells was inhibited, after the expression of EphB4 was knocked down. Conclusion: EPO could promote the differentiation and function of osteoblasts through ephrinB2/EphB4 signaling.

Key words: erythropoietin(EPO) ephrinB2/EphB4 signaling pathway, bone marrow stromal cell line, osteoblast differentiation

摘要： 目的：研究促红细胞生成素（EPO）通过ephrinB2/EphB4信号通路在细胞成骨分化中的作用。探讨EPO在骨稳态中的作用及其机制。方法：体外培养小鼠骨髓基质细胞系（ST2），加入EPO后，采用real-time PCR方法检测EphB4的表达以及成骨细胞相关基因的表达，采用ALP活性检测和茜素红染色观察EPO对成骨细胞功能的影响；在体外培养的ST2细胞中加入ephrinB2-Fc蛋白，模拟破骨细胞-成骨细胞共培养，使ephrinB-EphB4正向信号激活，采用上述方法检测其对成骨细胞的影响；进一步采用RNAi技术，使EphB4基因沉默，检测EPO对成骨细胞的影响。结果：EPO能增加ST2细胞RUNX2、ALP和Col1等成骨细胞相关基因的表达，同时伴随ST2细胞表面EphB4的表达升高，ALP活性和钙结节也增加；在模拟破骨细胞-成骨细胞共培养体系中，EPO也能促进ST2细胞的成骨向分化和功能；EphB4基因沉默后，EPO对ST2细胞的作用被减弱。结论：EPO能促进成骨细胞的分化和功能，该作用是通过ephrinB2/EphB4信号介导的。

关键词: 促红细胞生成素（EPO）；  , ephrinB2/EphB4信号通路；  , 骨髓基质细胞系；  , 成骨分化

CLC Number: 

• R782.2

• Q813.1