PTEN/mTOR信号通路对大鼠神经干细胞分化成熟作用的研究

The role of PTEN/mTOR signal pathway in differentiation and maturation of rat neural stem cells

目的探讨PTEN/mTOR信号通路对体外分离培养的大鼠神经干细胞(neural stem cells,NSCs)分化成熟的作用。方法体外分离培养大鼠海马神经干细胞,收集第三代神经干细胞分别诱导分化0d、1d、3d和7d,倒置显微镜下观察细胞形态变化,应用Western blot和细胞免疫荧光检测第10号染色体缺失的磷酸酶与张力蛋白同源物基因(PTEN)和反映雷帕霉素靶蛋白(mTOR)活性的磷酸化核糖体(P-S6R)蛋白的表达。结果与0d组和1d组相比,3d组PTEN表达明显增加(均P﹤0.01);7d组PTEN表达亦明显增加(P﹤0.01和P﹤0.05),而3d组和7d组P-S6R表达均明显下降(均P﹤0.01)。神经干细胞诱导分化后PTEN和P-S6R细胞免疫荧光染色均为阳性。结论 PTEN/mTOR信号通路参与调控神经干细胞的增殖分化和轴突生长,可能是导致神经干细胞分化成熟至一定阶段后增殖分化和轴突生长能力下降、不能建立有效的突触联系的重要原因之一。

Objective To explore the role of PTEN/mTOR signal pathway in rat neural stem cells （NSCs） differen- tiation in vitro. Methods Neural stem cells from rat hippocampus were cultured in vitro. The third generation NSCs were induced to differentiateion for 0 day, 1,3 and 7 days, respectively. Cells were observed under inverted microscope. The ex- pression of PTEN and P-S6R were detected by western blotting and immunofluorescence. Results Compared with 0d group and 1 d group,the expression levels of FFEN in 3d group（ both P 〈 0.01 ） and 7d group（ P 〈 0.01 ,P 〈 0.05 respective- ly） were increased significantly;Compared with 0d group and ld group,the expression levels of P-S6R in 3d group （both P 〈 0.01 ） and 7d group（both P 〈 0.01 ）were significantly decreased. Immunofluorescence staining of PTEN and P-S6R were both positive after NSCs differentiation for one day. Conclusion PTEN/mTOR signal pathway,which controls the pro- liferation and differentiation of NSCs as well as axon growth, may lower the capacity of NSCs proliferation, differentiation and axon growth in the process of NSCs differentiation and maturation,and cause ineffective synapse contact.