Activin A和Lefty A对人胚胎干细胞生长的影响

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。

Activin A and Lefty A affect self-renewal of human embryonic stem cells

Objective To explore the ettects ol Actlvm A ana L.efty A, two relateu factors of the TGF-β/Aetivin/Nodal signaling pathway, on the self-renewal of human embryonic stem cells （hESCs）. Methods We cultured hESCs in a feeder- and serum-free system with 1-100ng/ml Activin A and Lefty A. After 7 days of culture, hESCs were stained for alkaline phosphatase activity vesalts. Results Compared with that of the control medium （SR medium）, the percentage of undifferentiated colonies was significantly increased from 7.7% to 18.5%, 46.8%, 61.4%, 64.4% and 79.1% in the presence of 1, 3, 10, 30 and 100ng/ml Activin A, respectively. However, in the presence of 1, 3, 10, 30 and 100ng/ml Lefty A, compared with that of the control medium （MCM medium）, the percentage of undifferentiated colonies was decreased from 80. 5% to 72.4%, 74.6%, 72.2%, 69.5% and 65.3%. Activin A, even at a low concentration （lng/ml）, can signifi- cantly contribute to the self-renewal of hESC. However, Lefty A at a high concentration （I00ng/ml） can induce hESC to differentiate. Conclusion These results reveal the effects of the TGF-β/Activin/Nodal sig- naling pathway and related factors for regulating self-renewal and differentiation of hESCs.