流体切应力通过调节β2肾上腺素受体增强内皮祖细胞功能活性的机制研究

Sheer Stress Promotes Migration,Adherence and Proliferation of Endothelial Progenitor Cells in Vitro by Regulating β2 Adrenergic Receptor Expression

目的探讨流体切应力(shear stress,SS)对内皮祖细胞(endothelial progenitor cells,EPCs)功能的影响及其通过β2肾上腺素受体(β2 adrenergic receptor,β2AR)介导EPCs功能的机制。方法收集健康人群外周血30 ml,通过密度梯度离心法分离单个核细胞,采用EGM-2培养基培养和诱导EPCs分化;7天后体外采用生理范围15 dyn/cm2 SS处理培养EPCs 24h,检测EPCs表面β2AR表达水平变化以及对生物学功能如细胞迁移、黏附和增殖的影响;并分别加入β2AR激动剂(Fenoterol)、β2AR抑制剂(ICI118,511)、AKT阻滞剂(LY294002)或eNOS阻滞剂(L-NAME),观察β2AR/AKT/eNOS通路在SS调控EPCs功能中的作用。结果SS可促进EPCs表面β2AR的表达以及提高EPCs的生物学功能;SS、Fenoterol均可激活AKT/eNOS通路,增强EPCs的迁移、黏附和增殖能力;ICI118,511、LY294002、L-NAME均可阻断AKT/eNOS通路的激活,抑制SS对EPCs生物学功能的影响。结论体外SS可部分通过β2AR/AKT/eNOS通路增强EPCs的迁移、黏附和增殖能力。

Objective To investigate the mechanism by which shear stress(SS)mediated the function of endothelial progenitor cells(EPCs)via theβ2 adrenergic receptor(β2 AR).Methods The peripheral blood mononuclear cells were isolated from healthy subjects by using density gradient centrifugation and cultured in EGM-2 medium for 7 d.EPCs were exposed to 15 dyn/cm2 SS for 24 hr,and the expression ofβ2 AR as well as the migration,adhesion and proliferation abilities of EPCs were examined in vitro.The role of theβ2 AR/AKT/eNOS pathway in the regulation of EPCs by SS was also observed by the means of applyingβ2 AR agonist(Fenoterol),β2 AR inhibitor(ICI118,511),AKT inhibitor(LY294002)or eNOS inhibitor(L-NAME),respectively.Resultsβ2 AR was up-regulated significantly on EPCs and the migration,adhesion and proliferation abilities of EPCs were obviously enhanced upon SS.Exposure to SS or Fenoterol could both activate the AKT/eNOS pathway and improved the abilities of migration,adherence and proliferation of EPCs.Additionally,the activation of AKT/eNOS pathway and the improved migration,adhesion and proliferation abilities of EPCs induced by SS were significantly inhibited when treated with ICI118,511,LY294002,and L-NAME.Conclusion In vitro SS promotes the migration,adhesion and proliferation of EPCs partly through theβ2 AR/AKT/eNOS signaling pathway.