PDGF对人神经干细胞分化和甲状腺激素受体表达的影响

Effects of PDGF on Differentiation of Human neural Stem Cell and Expression of Thyroid Hormone Receptors

目的 探讨血小板衍生生长因子 (platelet-derived growth factor,PDGF)在神经干细胞 (neural stem cell,NSC)定向分化中的作用 ,以及 PDGF在 NSC分化过程中对甲状腺激素受体 (thyroid hormone receptors,TRs)表达的调控。方法 用免疫细胞化学方法鉴定分化后的细胞类型 ,分别用 RT-PCR半定量法、ELISA法检测不同诱导条件下 NSC分化前后 TR-α1 、TR-α2 、TR-β1 在转录与蛋白表达水平上的变化。结果 PDGF诱导分化后神经丝蛋白 (neurofilament protein,NF)细胞约占 80 % ;TR-α1 、TR-α2 、TR-β1 m RNA表达水平分别比 1 0 % (体积分数 )胎牛血清诱导分化组上调约 40 %、3 0 %、1 0 % (P<0 .0 5 )。TR-α、TR-β蛋白质表达趋势为 NSC>PDGF诱导分化组 >血清诱导分化组 (P <0 .0 5 )。结论 PDGF能引发 NSC向神经元分化 ,同时在转录与蛋白表达水平上调 NSC分化后 TR各亚型的表达 ,增强甲状腺激素对中枢神经系统发育的调控作用。

Objective To investigate the effects of platelet-derived growth factor (PDGF) on destined diffe- rentiation of human neural stem cell (NSC) and expression of thyroid hormone receptors (TRs) gene. Methods Human embryonic brain-derived NSCs were successfully expanded into neurospheres with mitogens and identified by nestin. PDGF, 10% (V/V) fetal bovine serum (FBS) was used to induce the differentiation of NSCs. After differentiation of NSCs, the cells were identified by immunocytochemistry method. The changes of TRs genes transcription were detected by semiquantitative reverse transcription-polymerse chain reaction (RT-PCR). The changes of TRs protein expressions were detected by ELISA. Results (1) NSCs induced by mitogens were nestin-positive. When NSCs were differentiated, the cells were NF-positive, and GC-positive or GFAP-positive. (2) After the NSCs were treated by PDGF, NF positive cell accounted for 80%. As compared with NSCs induced by 10% (V/V) serum, TR-α 1,TR-α 2,TR-β 1 transcription were up-regulated about 40%, 30%, 10% respectively ( P <0.05). (3) TRs protein expressions in NSCs were higher than differentiated cells. Conclusions PDGF might initiate neuron differentiation in NSC. After differentiation of NSC induced by PDGF, transcription and protein expressions level of TRs genes were up-regulated, which enhanced the crucial action of T 3 on the development of central nervous system.