Mfn2基因抑制Ras-PI3K-Akt信号途径并诱导大鼠血管平滑肌细胞凋亡

Adenovirus-mediated Gene Transfection of Mfn2 Promotes Apoptosis of Vascular Smooth Muscle Cells in Rats by Inhibiting Ras Signaling Cascade

目的应用腺病毒介导的转基因技术,研究过表达线粒体融合素基因-2(mitofusin-2,Mfn2)对WKY大鼠主动脉血管平滑肌细胞(rVSMCs)凋亡的影响并探讨其相关的信号通路。方法体外培养rVSMCs,感染含有Mfn2基因的腺病毒载体(Adv-Mfn2-GFP)。通过免疫组化染色显示细胞凋亡的形态学特征;采用琼脂糖凝胶电泳,Cell DeathELISA观察过表达Mfn2基因对细胞凋亡的影响;用Western blot检测感染Mfn2基因后不同时间点的磷酸化蛋白激酶B(p-Akt)和磷酸化细胞外信号调节激酶(p-ERK)水平的变化。结果rVSMCs感染Adv-Mfn2-GFP后能有效表达出相应蛋白;过表达Mfn2基因能明显促进rVSMCs凋亡,并抑制ET-1诱导的Akt活化和ERK活化,此作用显示出时间依赖性,且Akt活化受到的抑制更明显。结论过表达Mfn2基因能明显促进WKY大鼠主动脉血管平滑肌细胞凋亡,其分子机制是抑制Ras信号途径的活化,分子作用靶点可能是Ras-PI3K-Akt信号通路。

Objective To investigate the relationship between the overexpression of mitofusin-2 （Mfn2） and the apoptosis of aortic vascular smooth muscle cells （rVSMCs） from Wistar Kyoto inbred rats （WKY）, and its possible molecular signaling mechanism. Methods rVSMCs were transfected with an adenoviral vector expressing Mfn2 （Adv-Mfn2-GFP）. The morphological features of rVSMCs were detected by immunohistochemistry. The effect of overexpression of Mfn2 on the apoptosis of rVSMCs was investigated by DNA ladder and Cell Death ELISA. By using Western blot the phosphorylation status of Akt and ERK was detected at different time points after infection. Results The apoptosis of rVSMCs in culture transfected with Adv- Mfn2-GFP was remarkably promoted; the activation of Akt and ERK induced by ET-1 was markedly inhibited after the rVSMCs transfection with Adv-Mfn2-GFP in a time-dependent manner, and the suppressive effect of Akt was more obvious than ERK. Conclusion The overexpression of Mfn2 promoted apoptosis of rVSMCs by inhibiting the activation of Ras signaling pathway and probably via Ras-PI3K-Akt signaling pathway.