Persephin基因转染对缺氧诱导神经干细胞凋亡的影响

背景:如何抑制或减少神经干细胞凋亡的发生,促进缺氧后神经干细胞的存活,成为脑梗死神经干细胞移植治疗的研究热点。目地:观察在缺氧状态下转染人类persephin基因对神经干细胞凋亡的作用。设计:完全随机分组,对照实验。单位:中山大学附属第二医院神经内科。材料:实验于2006-07/2006-12在中山大学附属第二医院林百欣实验中心完成,重组腺病毒pAd persephin由本实验室构建保存,C17.2神经干细胞由美国哈佛大学医学院Snyder教授惠赠。胰蛋白酶、DMEM/F12购自Gibco公司;胎牛血清来自杭州四季青生物工程公司;多聚赖氨酸购自美国Sigma公司;TUNEL检测试剂盒,阳离子脂质体FuGENE购自瑞士Roche公司;S-P免疫组化试剂盒及DAB显色剂购自福建迈新生物工程公司;鼠抗人Nestin单抗,Persephin兔抗人多抗购自美国Santa Crus公司,persephin反义寡核脱氧苷酸由上海生工合成。方法:①实验干预:将携带人类Persephin基因的重组腺病毒感染C17.2神经干细胞,分为4组,A组:正常对照组,C17.2神经干细胞不作缺氧处理。B组:缺氧处理组,即置于37℃、体积分数0.95N2,体积分数0.05CO2厌氧培养箱培养。C组:缺氧 pAdpersiphin转染组,即:将携带人类Persephin基因的重组腺病毒感染C17.2神经干细胞,pAdpersiphin转染48h后的细胞置同B组条件的厌氧培养箱培养。D组:缺氧 pAdpersiphin转染组 persiphin反义寡核脱氧苷酸,即pAdpersiphin persiphin反义寡核脱氧苷酸转染。②实验评估:Western-blotting法分析Persephin蛋白的表达;TUNEL法检测凋亡指数;流式细胞术测定细胞凋亡率的变化。主要观察指标:Persephin蛋白的表达、细胞凋亡指数和凋亡率。结果:①Persephin蛋白表达:C组细胞经Western blot检测可见一特异性蛋白条带存在,Mr约为24000,符合预期结果,说明persiphin成功表达,D组亦可见一Mr 24000的条带,但条带较单纯pAdpersiphin感染组明显为淡,说明反义persiphin反义寡核脱氧苷酸可成功抑制pAdCMVpersiphin的表达。②细胞凋亡指数:C组凋亡细胞明显减少,凋亡指数低于B、D组(P<0.01),但高于A组(P<0.01),表明细胞凋亡未完全避免。③细胞凋亡率:B、D组凋亡率明显高于A组(P<0.01),C组明显较B组、D组低(P<0.01)。结论:腺病毒介导的Persephin基因能高效表达Persephin;外源性Persephin对C17.2神经干细胞具有抗凋亡作用,能够提高C17.2神经干细胞对缺氧的耐受性。

Effect of Persephin gene transfer on hypoxia induced neural stem cell apoptosis

BACKGROUND: Looking for effective measures to ensure the survival of the implanted stem cells against ischemia-induced hypoxia becomes the major concern in the research of cell transplantation therapy for cerebral infarction.OBJECTIVE: To study the effects of human Persephin gene transfer on hypoxia-induced apoptosis of neural stem cells.DESTGN: A randomized controlled basic study on cells.SETTTNG: Department of Neurology, the Second Affiliated Hospital of Sun Yat-sen University.MATERTALS: This study was completed in the Lin Baixing Laboratory Center of the Second Affiliated Hospital of Sun Yat-sen University from July to December in 2006. Recombinant adenovirus pAdCMV persephin was constructed in our lab. C17.2 neural stem cells were kindly provided by Prof. Snyder, Harvard Medical University, USA. Trypsin and DMEM/F12 were purchased from Gibco Company (USA), fetal bovine serum (FBS) from Sijiqing Biological Engineering Materials Co. Ltd (Hangzhou, China); Poly-lysine from Sigma Company (USA), TUNEL assay kit and FuGENE kit from Roche Molecular Biochemicals Company (Swiss), and S-P immunohistochemical detection kit and DAB reaction kit from Mycine Biological Engineering Company (Fujian). Rat anti-human monoclonal Nestin antibody and rabbit anti-human polyclonal persephin antibody were manufactured by Santa Cruz Company (USA), and persephin anti-senseoligodeoxynucleotide (ODN) was synthesized by Shanghai Biological Engineering Company.METHODS: ① Interventions: C17.2 neural stem cells cultured in vitro were infected by recombinant adenovirus containing persephin gene, and they were divided into four groups: blank control group (Group A, in which the C17.2 neural stem cells were not treated with hypoxia), hypoxic group Group B, in which the cells were cultured at 37 ℃ in anaerobic incubation containing N2 (0.95 in volume fraction) and CO2 (0.05 in volume fraction)], hypoxia + pAdCMV persephin infection group Group C, where the cells were cultured under the conditions as in group B after pAdCMV persephin infection for 48 hours], and hypoxia + pAdCMV persephin infection + anti-sense persephin ODN group (Group D, where the cells were infected by pAdCMV persephin and anti-sense persephin ODN. ② Evaluation: The expression of Persephin protein was analyzed using Western blotting; Apoptotic index was detected with terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) assay; The changes of apoptotic rate was determined with flow cytometry.MAIN OUTCOME MEASURES: Expression of Persephin protein; Apoptotic index; Apoptotic rate.RESULTS: ① Expression of Persephin protein: A specific band (relative molecular mass of 24 000) was detected by Western blotting in pAdCMV persephin infected cells, suggesting the successful expression of persephin gene.Interestingly, the cells infected with both pAdCMV persephin and anti-sense persephin ODN also showed the specific band of about 24 000, but with much less density, indicating that anti-sense persephin ODN could effectively inhibit the expression of pAdCMV persephin. However, this band was not presented in the blank control groups. ② Apoptotic index:The apoptotic index in group C was significantly lower than those in groups B and D (P＜0.01), but still higher than that of group A (P＜0.01), suggesting that persephin gene transfer could attenuate apoptosis to some extent. ③ Apoptotic rate: The apoptotic rate in groups B and D were obviously higher than that in group A (P ＜ 0.01), and it was lower in group C than in groups B and D (P＜0.01).CONCLUSION:Recombinant adenovirus can efficiently mediate Persephin gene transfer into C17.2 neural stem cells,resulting in high expression of the exogenous Persephin in vitro, which effectively reduces C17.2 neural stem cell apoptosis induced by hypoxia.