p27基因对血管平滑肌细胞中连接蛋白43表达的影响

Effect of p27 gene on expression of connexin43 in vascular smooth muscle cells

目的研究连接蛋白43(Cx43)在p27基因抑制血管平滑肌细胞(VSMC)增殖中的作用。方法以携带大鼠p27基因表达序列的复制缺陷型5型腺病毒载体(AdCMV-p27)转染VSMC后,应用免疫细胞化学染色检测p27和Cx43表达的变化;应用3H标记的胸腺嘧啶核苷(3H-TdR)掺入试验观察p27基因表达增强对VSMC增殖的影响。结果(1)Ad-CMV-p27转染前,血小板衍化生长因子BB(platelet-derived growth factor,PDGF-BB)下调P27蛋白的表达,AdCMV-p27转染后,无论有无PDGF-BB刺激,VSMC中P27蛋白的表达均比转染前显著增高。(2)AdCMV-p27转染使VSMC中Cx43蛋白的表达基本恢复至有丝分裂原刺激前状态。(3)AdCMV-p27转染使VSMC的3H-TdR掺入量均较未转染组显著降低。结论p27基因对Cx43表达的调控,使细胞间连接通讯得到维护,是其抑制VSMC增殖的重要机制之一。

Objective To investigate the role of connexin 43 in p27 gene inhibited vascular smooth muscle cells（VSMCs） proliferation. Methods The expressions of P27 and connexin43 were evaluated by immunocytochemical staining and the effect of p27 overexpression on VSMCs proliferation was observed by 3H-thymidine incorporation. Results （1）Before AdCMV-p27 was transfected to VSMCs, P27 protein was down-regulated by platelet-derived growth factor （PDGF） BB. After AdCMV-p27 was transfected to VSMCs, the level of P27 protein expression was significantly higher than that before transfection, and no correlation with the stimulation of PDGF-BB. （2） After AdCMV-p27 was transfected to VSMCs, the pattern of connexin43 protein expression almost recovered to that in quiescent VSMCs. Conclusion The mechanism of p27 inhibiting VSMCs proliferation involves that p27 regulate CX43 expression and maintain normal inter-cellular junctional communication.