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目的探讨TGF-β/Activin/Nodal信号通路的相关因子Activin A和Lefty A在一定浓度范围内,对人胚胎干细胞(hESC)自我更新的影响。方法在hES3细胞株的无滋养层无血清培养体系中加入1-100ng/ml的Activin A和Lefty A。7天后,通过碱性磷酸酶染色法对hES3细胞的自我更新状态进行评估。结果 Activin A在浓度为1,3,10,30和100ng/ml时,与阴性对照(SR培养基)组相比,未分化克隆的比率从7.7%分别提高到了18.5%,46.8%,61.4%,64.4%和79.1%,差异有统计学意义(P<0.01)。Lefty A组在浓度为1,3,10,30和100ng/ml时,与阴性对照(MCM培养基)组相比,未分化克隆的比率从80.5%分别降低到了72.4%,74.6%,72.2%,69.5%和65.3%,在浓度为100ng/ml时,差异有统计学意义(P<0.05)。结论较低浓度的Activin A即能有效维持hESC的自我更新,而较高浓度的Lefty A能诱导hESC分化。该结果进一步揭示了TGF-β/Activin/Nodal信号通路及其相关因子对hESC自我更新和分化的作用特点,有待对其机制进行深入研究。
Objective To investigate the effect of Activin A and Lefty A, a factor involved in TGF-β / Activin / Nodal signaling pathway, on the self-renewal of human embryonic stem cells (hESCs) in a range of concentrations. Methods 1-100 ng / ml Activin A and Lefty A were added to the trophoblast-free serum-free culture system of hES3 cell line. After 7 days, the self-renewal status of hES3 cells was assessed by alkaline phosphatase staining. Results Activin A increased the percentage of undifferentiated clones from 7.7% to 18.5%, 46.8% and 61.4% respectively at the concentrations of 1, 3, 10, 30 and 100 ng / ml, compared with the negative control (SR medium) , 64.4% and 79.1% respectively, with significant difference (P <0.01). The percentage of undifferentiated clones decreased from 80.5% to 72.4%, 74.6% and 72.2% respectively in Lefty group A at the concentrations of 1, 3, 10, 30 and 100 ng / ml compared with the negative control (MCM medium) , 69.5% and 65.3%, respectively. The difference was statistically significant at the concentration of 100ng / ml (P <0.05). Conclusion Activin A at a lower concentration can effectively maintain the self-renewal of hESC, while higher concentration of Lefty A can induce hESC differentiation. The results further reveal the characteristics of TGF-β / Activin / Nodal signaling pathway and its related factors on hESC self-renewal and differentiation, pending further study of its mechanism.