Feline neural progenitor cells II: use of novel plasmid vector and hybrid promoter to drive expression of glial cell line-derived neurotrophic factor transgene.

Sustained transgene expression is required for the success of cell transplant-based gene therapy. Most widely used are lentiviral-based vectors which integrate into the host genome and thereby maintain sustained transgene expression. This requires integration into the nuclear genome, and potential risks include activation of oncogenes and inactivation of tumor suppressor genes. Plasmids have been used; however lack of sustained expression presents an additional challenge. Here we used the pCAG-PyF101-eGFP plasmid to deliver the human GDNF gene to cat neural progenitor cells (cNPCs). This vector consists of a CAGG composite promoter linked to the polyoma virus mutant enhancer PyF101. Expression of an episomal eGFP reporter and GDNF transgene were stably maintained by the cells, even following induction of differentiation. These genetically modified cells appear suitable for use in allogeneic models of cell-based delivery of GDNF in the cat and may find veterinary applications should such strategies prove clinically beneficial.