Wnt 3a在神经干细胞向多巴胺能神经元分化过程中作用的研究

Wnt信号在中枢神经系统发育过程中起重要的作用,控制着细胞的生长及分化.Wnt3a是Wnt家族的成员之一,对神经干细胞的增殖及分化有一定的调控作用.将重组Wnt3a腺病毒转入神经干细胞中,研究Wnt3a在定向诱导神经干细胞向多巴胺能神经元分化过程中的作用.将神经干细胞分为4组,对照组(不加任何诱导因子组)、抗坏血酸诱导组(AA组)、Wnt3a重组腺病毒诱导组(Wnt3a组)以及Wnt3a重组腺病毒加抗坏血酸诱导组(Wnt3a AA组).结果显示,Wnt3a组细胞中的多巴胺能神经元前体细胞特异性标志Nurr1表达量显著增多,Wnt3a AA组多巴胺能神经元明显多于AA组,酪氨酸羟化酶(TH)在mRNA水平上的表达是AA组的1.86倍.蛋白质印迹及免疫细胞化学染色显示,各诱导组均有TH的表达,Wnt3a组和AA组多巴胺能神经元阳性细胞数比例分别为(5.76±3.34)%和(37.42±2.54)%,与Wnt3a AA组(73.96±2.61)%比较,差异有统计学意义(P<0.05).利用高效液相色谱法检测到诱导后的细胞可分泌多巴胺.结果表明,Wnt3a可促进神经干细胞向多巴胺能神经元前体细胞分化,再通过抗坏血酸的诱导作用,在体外可获得大量的多巴胺能神经元,这些神经元有分泌多巴胺的功能.

Wnt3a is Important in The Differentiation From Neural Stem Cell Into Dopaminergic Neuron In vitro

Wnt signaling is implicated in the control of cell growth and differentiation during neural stem cell(CNS) development.Wnt3a, one of wnt gene family members, has effect on regeneration neurospheres and differentiation into neurons.Wnt3a inhibits regeneration of neurospheres, and promotes its differentiation. In vitro neurosphere was cultured in a serum-free defined medium DMEM/F12 supplemented with bFGF and EGF. Dissociated cells were plated onto poly-d-lysine-coated coverslips and propagated in medium containing recombined Wnt3a-adenovirus. Plenty of Nurr1 were detected by RT-PCR after 3 days. Wnt3a combined AA would improve NSC differentiation into dopaminergic (DA) neuron. The quantity of DA neuron is obviously more than the AA alone group's. Moreover, the expression of TH mRNA is 1.86 fold in Wnt3a combined AA group. Induced cells were immunostained for TH and DAT. The proportion of TH-positive was (37.42±2.54) % (P<0.05) in the AA group , accordingly in Wnt3a combined AA group it was (73.96±2.61) % (P<0.05). These results indicate that Wnt3a promoted the proliferation of precursor cells expressing the orphan nuclear receptor-related factor 1 (Nurr1) . Large numbers of DA neurons are obtained by adding AA in the culture of NSC modified Wnt3a in vitro. Therefore, the successful conversion of neural stem cells in vitro resulting in the desired dopaminergic neuronal phenotype, could provide a solution to the problem of limited availability for clinical surgical transplantation therapies, which are currently in progress for the treatment of neurodegenerative diseases such as Parkinson's disease. These findings indicate that Wnt3a is key regulators of proliferation and differentiation of DA precursors.