神经调节蛋白-1诱导小鼠胚胎干细胞向心肌细胞分化

Neuregulin-1 induces differentiation of cardiomyocytes from embryonic stem cells

目的观察神经调节蛋白-1(NRG-1)诱导小鼠胚胎干细胞(ESCs)向心肌细胞分化及扩增心肌细胞的作用。方法分别观察ESCs自发及NRG-1诱导情况下心肌细胞分化率;RT-PCR检测心肌早期转录因子GATA-4、Nkx2.5mRNA及心肌骨架蛋白α-MHC、β-MHCmRNA的表达;细胞免疫组化检测心肌α-actinin蛋白表达;血管活性药物刺激观察心肌细胞的功能反应。结果NRG-1诱导的心肌细胞分化率显著高于自发的心肌细胞分化率(P<0.05),且诱导生成的心肌细胞对肾上腺素能及胆碱能药物刺激呈现相应的频率反应,刺激前后搏动频率差异均有统计学意义(P<0.05);NRG-1呈剂量依赖性上调GATA-4、Nkx2.5mRNA的表达,在NRG-1为100ng/mL时表达水平最高,且两者的相对表达量明显高于自发分化组的相对表达量(P<0.05或P<0.01);NRG-1干预增加心肌细胞骨架蛋白α-MHC、β-MHCmRNA水平且增强α-actinin蛋白表达(P<0.05)。结论外源性NRG-1早期干预能够诱导ESCs向心肌细胞分化并扩增ESCs分化形成的心肌细胞。

Objective To observe the role of neuregulin-1 （NRG-1） in differentiation of cardiomyocytes from embryonic stem cells （ESCs）. Methods The differentiation rates of cardiomyocytes from ESCs with or without NRG-1 induction were observed. The expression of cardiac-restricted transcription factors Nkx2.5 and GATA-4 mRNA and cardiac-specific α-/β-myosin heavy chain （α-/β-MHC） mRNA was detected by RT-PCR. The expression of sarcomeric α-actinin protein was evaluated with immunohistochemistry. Results Compared to those of spontaneous differentiation, the differentiation rates of cardiomyocytes were significantly higher in the presence of NRG-1 （P 〈 0.05）. NRG-1 significantly up-regulated the expression of Nkx2.5 and GATA-4 mRNA in a dose-dependent manner, and the peak expression was achieved in the presence of 100 ng/mL NRG-1. NRG-1 treatment significantly increased the expression of α-/β-MHC mRNA and α-actinin （P 〈 0.05）. Conclusion Earlier treatment with exogenous NRG-1 induces differentiation of cardiomyocytes from ESC.