Bmi1在低切应力抑制血管内皮细胞迁移中的作用

The Role of Bmi1 on Migration of HUVECs under Low Shear Stress

目的探讨低切应力刺激对血管内皮细胞Bmi1表达的影响及其在迁移中的作用。方法体外原代培养人脐静脉内皮细胞(human umbilical vein endothelial cells,HUVECs),运用平行平板流动腔系统给HUVECs加载正常切应力(1.5 Pa)和低切应力(0.5 Pa)12 h,用实时定量PCR法和免疫印迹法检测Bmi1 mRNA和蛋白表达水平,用细胞划痕实验检测细胞迁移能力,利用特异性小干扰RNA(siRNA)转染技术沉默Bmi1基因。结果HUVECs受力12 h后,与1.5 Pa切应力组相比,0.5 Pa低切应力能显著上调Bmi1表达,同时抑制细胞迁移。siRNA敲低Bmi1表达后,减弱了低切应力对HUVECs迁移的抑制作用。结论低切应力对HUVECs迁移的抑制作用可能是通过上调Bmi1蛋白的表达实现。Bmi1表达沉默后可逆转低切应力对HUVECs迁移的抑制。

Objective To investigate the role of Bmi1 on the migration of human umbilical vein endothelial cells(HUVECs)in response to low shear stress.Methods A parallel plate flow chamber system was used to generate low(0.5 Pa)or normal(1.5 Pa)laminar shear stress.HUVECs were isolated,cultured and exposed to flow for 12 hours.The mRNA and protein levels of Bmi1 were analyzed by real-time PCR and Western blot,respectively.Meanwhile,wound healing assay was performed to determine the migration of HUVECs.Bmi1 specific small interference RNA(siRNA)was used to silence Bmi1 gene.Results Low shear stress(0.5 Pa)significantly inhibited migration of HUVECs compared with normal shear stress(1.5 Pa).Similarly,compared with HUVECs exposed to normal shear stress,the expression of Bmi1 significantly increased in HUVECs exposed to low shear stress.Small interfering RNA knockdown of Bmi1 attenuated low shear stress-induced inhibition of HUVECs migration.Conclusions Low shear stress may inhibit the migration of HUVECs through up-regulation of Bmi1 expression.Knockdown of Bmi1 may reverse the HUVECs migration inhibited by low shear stress.