Prolonged transgene expression in glomeruli using an EBV replicon vector system combined with HVJ liposomes

Abstract

Background: Various gene transfer vectors as well as delivery systems have been developed; however, many problems remain to be solved. We already achieved a technique to introduce genes into glomerular mesangial cells by hemagglutinating virus of Japan (HVJ) liposome-mediated gene transfer via renal artery. The main limitation of this method is the transient transgene expression.

Method: For long-term gene expression in glomeruli, Epstein-Barr virus (EBV) replicon-based plasmid was employed, containing the latent viral DNA replication origin (oriP) and EBV nuclear antigen-1 (EBNA-1), which are the minimum EBV component of transgene-nuclear retention. To examine the effect of EBV replicon apparatus on the duration of transgene expression in glomeruli in vivo, the EBV replicon vector pEBActLuc, and the control plasmid vector pActLuc were adopted. These plasmid vectors were transferred into the kidney via renal artery by using artificial viral envelope (AVE)-type HVJ liposome method, and glomerular luciferase activities were analyzed at various time points after transfection.

Results: On day 4, pEBActLuc and pActLuc transfer resulted in equal glomerular luciferase activity, and the luciferase gene expression was sustained for at least 56 days in glomeruli transfected with pEBActLuc, whereas it was reduced on seven days in glomeruli transfected with pActLuc.

Conclusion: The combination of EBV replicon apparatus and HVJ liposomes appears to be a powerful tool for long-term gene expression in vivo, and furthermore, it may be a promising new therapeutic method for the progression of renal disease.