Induction of efficient differentiation and survival of porcine neonatal pancreatic cell clusters using an EBV-based plasmid expressing HGF

Porcine neonatal pancreatic cell clusters (NPCCs) have been actively studied as a source of pancreatic stem cell transplantation for the treatment of diabetes. In this study, the hepatocyte growth factor (HGF) gene was cloned in an Epstein-Barr virus (EBV)-based plasmid vector (pEBVHGF) and the effects of the HGF expression on the survival and differentiation of NPCCs were analysed. For comparison, pHGF was constructed by deleting EBNA-1 and OriP from pEBVHGF. The expression of HGF, as measured by ELISA, lasted longer when pEBVHGF was used than when pHGF was used. C-Met phosphorylation co-related with the expression of HGF in the transfected NPCCs. Immunocytochemistry experiments showed that NPCCs showed a higher and longer expression of insulin when they were transfected with pEBVHGF than with pHGF. Moreover, a greater number of NPCCs survived for a longer period after they were transfected with pEBVHGF than when they were transfected with pHGF. Taken together, these results indicate that transfecting NPCCs with the HGF gene using an EBV-based plasmid is a more effective method of inducing differentiation to beta cells and enhancing survival than using a conventional plasmid. Therefore, it may be possible to use EBV-based plasmids to modify pancreatic stem cells for xenotransplantation.