含GDNF基因的慢病毒载体的构建和其在人胚胎神经干细胞中的表达

Construction of Lentiviral Vectors Encoding GDNF and GDNF Expression in Human Neural Stem Cells

摘要:

利用含胶质源性神经营养因子(Glial cell derived neurotrophic factor, GDNF)基因的慢病毒(Lentivirus)载体转染了人胚胎来源的神经干细胞, 探讨了转染后GDNF在神经干细胞中的体外表达水平及其影响因素。首先GDNF基因被克隆入慢病毒载体, 通过瞬时转染法包装出病毒上清, 经滴度鉴定后分别按拷贝数分别为 1、2.5、5、10转染神经干细胞。转染后细胞经过潮霉素筛选得到均一表达GDNF的神经干细胞体系。其后分别利用酶联免疫吸附(ELISA)方法和Real-time PCR方法测定不同转染组细胞在不同时间点GDNF的蛋白分泌水平和基因表达水平。实验中构建了表达GDNF基因的慢病毒载体, 包装出的病毒上清在体外培养条件下成功转染了神经干细胞, 经潮霉素筛选可以得到均一的持续表达分泌GDNF的人胚胎皮层神经干细胞体系。实验结果表明转染拷贝数可以影响GDNF的分泌水平, 相同条件下转染拷贝数越高, GDNF分泌量越多, 其基因表达水平越高。因此, 含GDNF的慢病毒载体可以成功转染人胚胎来源的神经干细胞, 使其持续表达GDNF, 转染过程中可以通过拷贝数在一定水平上控制GDNF的蛋白分泌水平和基因表达水平。

Abstract:

We transfect human neural stem cells using lentiviral vectors encoding glial cell line derived neurotrophic factor (GDNF) to study its expression level in vitro and to get a stable cell line expressing GDNF. First, GDNF gene was sub-cloned into the lentiviral transfer vectors. Then, the recombinant lentiviral supernatants were packaged by 293T cells through three plasmids transient co-transfection method using standard lipofectamine reagent. The viral titers were tested by the transfection efficiency of 293T cells. At the same time, hNSChuman neural stem cells were transfected under different multiplicity of infection. GDNF gene expression level and its protein secretion level of hNSC were tested by real-time PCR and ELISA methods after transfection. Lentiviral vectors encoding GDNF were constructed. Using lentiviral vectors encoding GDNF we successfully transfected human neural stem cells, and got a stable neural stem cell lines over-expressing GDNF. Furthermore, the results indicated that GDNF expression was influenced by the multiplicity of infection. Human neural stem cells could over-express GDNF through lentivial vectors tranfection. Its gene expression level and protein expression level correlate with the multiplicity of infection.