建立以α-突触核蛋白损伤为靶点的细胞筛选模型

摘要

目的：建立以α-突触核蛋白损伤为靶点筛选抗帕金森病创新药物的细胞模型。方法通过 PCR 方法扩增目的基因，分子克隆技术构建原核表达载体。融合载体转化至大肠杆菌诱导后表达重组α-突触核蛋白，亲和层析法纯化目的蛋白并通过蛋白免疫印迹和质谱技术进行鉴定，MTT 法检测细胞存活率。结果α-突触核蛋白基因的 cDNA 片段与理论分子量大小一致，并成功克隆至载体 pET30a；测序正确的融合载体转化至大肠杆菌 E．Coli．BL21（DE3）。转化子经异丙基-β-D-硫代半乳糖苷（IPTG）诱导表达α-突触核蛋白，通过改变温度、IPTG 浓度及宿主菌的增殖状态等条件，获得高表达菌株；宿主菌的裂解液通过亲和层析方法获得纯化的α-突触核蛋白，纯化蛋白通过与不同抗体免疫印迹结果证明为α-突触核蛋白，质谱结果显示其分子质量为15.3 ku，与理论分子质量15.5 ku 基本一致。纯化的α-突触核蛋白刺激 PC12细胞及原代神经元细胞后，细胞存活率明显下降，存活率的降低程度与α-突触核蛋白刺激浓度呈正相关性。结论成功建立了以α-突触核蛋白损伤为靶点的细胞筛选模型，可用于筛选具有抗帕金森病功能的创新化合物。%Aim To construct the cell model targeted on the damage by α-synuclein for screening anti-Parkinson’s Disease (PD)compounds.Methods The cDNA fragment of α-synucle-in gene was obtained by PCR methods and inserted into the re-combinant prokaryotic plasmid by molecular cloning technique. The recombinant plasmid was transformed into Escherichia coli, and subsequently induced to express α-synuclein protein.The recombinant α-synuclein was purified and identified by affinity chromatography,immunoblotting and mass spectrometry.The cells damage by α-synuclein was evaluated through cell viability measured by 3-(4,5-dimethyl-2-thiazolyl )-2,5-diphenyl-2-H-tetrazolium bromide.Results The obtained cDNA fragment ofα-synuclein in accordance with its theoretic molecular weight was cloned into pET30a plasmid and verified by sequencing.The re-combinant plasmid was transformed into bacteria E.Coli.BL21 (DE3)and induced to express α-synuclein by isopropyl β-D-1 -thiogalactopyranoside (IPTG).The expression condition was op-timized according to the culture temperature,the concentration of IPTG and the proliferation state of bacteria.The purified α-synu-clein was proved to be a 1 5.3 ku molecule weight protein,and could be immunoblotted with anti-α-synuclein antibody.The pu-rified α-synuclein could decrease the viability of PC1 2 cells and primary neurons significantly,and its effect was in a concentra-tion-dependent manner.Conclusion We have succeeded in constructing the cell model targeted on the damage by α-synucle-in.