Construction and identification of lentiviral vector harboring interference RNA targetting murine TNF-αgene / 中国免疫学杂志

ABSTRACT

Objective:To construct recombinant lentiviral vectors harboring interference RNA ( RNAi ) targetting murine TNF-αgene,so as to lay the foundation on the RNAi gene therapy.Methods: Three small interfering RNA ( siRNA) sequences targeting murine TNF-αgene ( siRNA1,siRNA2,siRNA3) and negative-control siRNA were designed and synthesized.The inhibition effects of siRNAs on TNF-α,IL-1βand IL-6 secretion of LPS-stimulated RAW264.7 macrophages were observed using real-time PCR and ELISA methods.DNA oligo was designed and synthesized according to the most effective siRNA 2 sequence.The recombinant lentiviral shuttle plasmid expressing short hairpin RNA ( shRNA) was constructed and sequenced.The lentiviral shuttle plasmids with packaging plasmids were transfected into 293T cells to produce lentiviral particles.Results: ①The TNF-αmRNA relative expression levels of siRNA1, siRNA2 and siRNA3 were 0.24±0.01,0.16±0.02,0.19±0.01 respectively,significantly lower than that of negative control (0.95± 0.02) (F=531.3,P0.05).②The TNF-αprotein expression levels of siRNA1,siRNA2 and siRNA3 were (23.95±1.21),(17.27±1.46),(19.07± 1.57)ng/ml respectively,significantly lower than that of negative control (35.37±2.93)ng/ml (F=18.1,P=0.000 6<0.001).The inhibition rates of protein expression were 32.29%, 51.16%, 46.08%, respectively comparing with negative control.③The PCR product electrophoresis showed that recombinant vectors yielded 343 bp fragments,non-constructed vectors yielded 306 bp fragments.DNA sequencing partially showed insertion sequence.④Lentiviral particles were obtained by transfecting 293T cells with recombinant lentiviral shuttle plasmids and lentiviral packaging plasmids.Cells grew well during virus production with strong fluorescence expression.The titer of concentrated virus was 2×106 TU/μl.Conclusion:The lentiviral vector harboring RNAi targeting murine TNF-αgene has been successfully constructed.