MiR-133a调控BMP-2诱导的血管平滑肌细胞向成骨样细胞分化的机制

Mechanism of Regulation of BMP-2-Induced Osteoblastic Differentiation of Vascular Smooth Muscle Cells by MiR-133a

目的研究MiR-133a调控BMP-2诱导的血管平滑肌细胞向成骨样细胞分化的机制。方法采用BMP-2处理大鼠血管平滑肌细胞72h建立成骨样细胞分化模型。实验分组与细胞处理方法:1)空白对照组:采用溶媒处理血管平滑肌细胞72h;2)模型对照组:采用BMP-2处理血管平滑肌细胞72h;3)MiR-133a组:采用BMP-2处理MiR-133a转染的血管平滑肌细胞72h;4)MiR-NC组:采用BMP-2处理MiR-NC转染的血管平滑肌细胞72h。通过免疫荧光染色和细胞形态鉴定原代大鼠血管平滑肌细胞表型。检测大鼠血管平滑肌细胞内钙离子浓度、碱性磷酸酶(ALP)活性、骨钙素(OC)水平、骨相关蛋白(Runx2、Osterix)表达及细胞凋亡情况。结果过表达MiR-133a能显著抑制BMP-2诱导的血管平滑肌细胞钙离子浓度、ALP活性及OC水平的增加(P<0.05),能显著抑制BMP-2诱导的血管平滑肌细胞Runx2、Osterix蛋白表达(P<0.05),同时能显著抑制BMP-2诱导的血管平滑肌细胞的凋亡(P<0.05)。结论 MiR-133a可以显著抑制BMP-2诱导的血管平滑肌细胞向成骨样细胞分化,其机制可能是抑制BMP-2引起的骨相关蛋白的增加和阻碍BMP-2诱导的大鼠血管平滑肌细胞凋亡。

Objective To investigate the mechanism of miR-133a action in BMP-2-induced osteoblastic differentiation of vascular smooth muscle cells(VSMCs).Methods Osteoblastic differentiation was induced by treating rat VSMCs with BMP-2for72hours.Cells were divided into four treatment groups:(1)control group:VSMCs were treated with solution medium;(2)model group:VSMCs were treated with BMP-2;(3)miR-133a group:miR-133a-transfected VSMCs were treated with BMP-2;(4)miR-NC group:miR-NC-transfected VSMCs were treated with BMP-2.The primary rat VSMCs were identified by immunofluorescent staining and morphological analysis.Calcium ion concentration,alkaline phosphatase(ALP)activity,OC content,expression of osteogenic proteins(Runx2and Osterix),and cell apoptosis were detected in VSMCs.Results MiR-133a overexpression significantly inhibited BMP-2-induced increase in calcium ion concentration,ALP activity and OC content,as well as in Runx2and Osterix expression and cell apoptosis(P<0.05).Conclusion MiR-133a can significantly suppress BMP-2-induced osteoblastic differentiation of VSMCs,and the mechanism may be involved in the inhibition of BMP-2-caused increase in bone-related proteins and apoptosis.