人IL-1受体拮抗蛋白重组逆转录病毒载体的构建、鉴定及在骨关节炎软骨细胞中的表达

CONSTRUCTION AND IDENTIFICATION OF RECOMBINANT RETROVIRAL VECTOR CONTAINING HUMAN INTERLEUKIN 1 RECEPTOR ANTAGONIST AND ITS EXPRESSION IN OSTEOARTHRITIC HUMAN ARTICULAR CHONDROCYTES

目的构建含人IL-1受体拮抗蛋白(IL-1 receptor antagonist,IL-1Ra)逆转录病毒表达载体(PLXRN-IL-1Ra),体外转染人骨关节炎(osteoarthritis,OA)软骨细胞,研究其相关特性。方法利用细菌内同源重组技术快速构建PLXRN-IL-1Ra逆转录病毒重组质粒,经测序及酶切鉴定正确后转染PT67细胞,包装成为重组PLXRN-IL-1Ra逆转录病毒,并使用小鼠肾成纤维细胞系NIH/3T3对病毒进行滴度测定。实验分为3组:未转染组(A组)、PLXRN空质粒转染组(B组)、PLXRN-IL-1Ra转染组(C组),病毒感染人OA软骨细胞后,RT-PCR检测细胞内IL-1Ra基因的转录和表达;ELISA法检测细胞培养上清液中人IL-1Ra蛋白表达。结果酶切鉴定及基因测序证实重组逆转录病毒质粒中含有人IL-1Ra cDNA,测定包装的病毒滴度为3×104CFU/mL。原代软骨细胞体外培养呈多角形或梭形,甲苯胺蓝染色见细胞内有紫色异染颗粒。RT-PCR结果显示在C组出现311bp人IL-1Ra mRNA片段,A、B组未见人IL-1Ra mRNA的表达带,GAPDH在各组均有表达。ELISA检测发现C组细胞上清有一定量的人IL-1Ra表达,蛋白浓度为(60.47±15.13)ng/L,A组和B组均无人IL-1Ra表达。结论构建的IL-1Ra逆转录病毒表达载体成功地感染人OA软骨细胞,并在体外获得稳定表达,为将表达人IL-1Ra基因的人OA软骨细胞用于OA基因治疗提供了实验依据。

Objective To construct the retroviral vector containing human interleukin 1 receptor antagonist （IL-1Ra） and to investigate the property of the transfected articular chondrocytes from osteoarthritic patients in vitro. Methods Retrovir al vector PLXRN carrying IL-1Ra （PLXRN-IL-1Ra） gene was constructed by inserting IL-1Ra gene at the sites of Sal I and BamH I. The recombinant retroviral plasmid was homologously recombinated in bacterial cells. After screening and amplification, the recombinant retroviral plasmid was obtained and transfected into PT67 cells. The replication-defective retrovirus PLXRN-IL- 1Ra was packed and amplified in the PT67 cells. Viral titer was determined by infecting NIH/3T3 cells with serially diluted viral supernatants produced with a control vector. Experiments were divided into 3 groups： non-transducted group （group A）, PLXRN transduction group （group B）, PLXRN-IL-1Ra transduction group （group C）. Primary articular chondrocytes from osteoarthritic patients were transduced with PLXRN and PLXRN-IL-1Ra.The positive chondrocytes clones, which were G418- resistant, were cultured for 3-4 weeks after being selected by G418. The expression of IL-IRa mRNA in the chondrocytes was determined by RT-PCR. Levels of IL-1Ra protein synthesis in the supernatants were measured by ELISA. Results Restric tive endonuclease identification and gene sequencing confirmed that the recombinant contained IL-1Ra cDNA. Virus titer could reach 3 × 10^4 CFU/mL. Primary chondrocytes cultured in vitro were polygonal or spindle and were stained with purple particles by toluidine blue staining. After stable transduction into the chondrocytes the 311 bp fragment of IL-1Ra was detected in group C by semi-quantitative RT-PCR. ELISA showed that IL-1Ra in supernatants of the group A and group B were below the level of detection. The concentrations were （60.47 ± 15.13 ） ng/L in group C .There were significant differences between gene transduction group and control groups （P 〈 0.05）. Conclusion The construction of recombinant retrovirus vector by homologous recombination in bacterial cells can be quickly and easily performed. Stable and effective expression of IL-1Ra can be achieved by transduction with retroviral vectors in osteoarthritic articular chondrocytes, indicating potential utility in gene therapy for osteoarthritis.