Direct Electroporation of the Murine Lung greatly Enhances Reporter Gene Expression following Intranasal Delivery of Plasmid DNA.

Pringle IA, Sumner-Jones SG, Davies LA, Varathalingam A, Lawton AE, Gill DR, Hyde SC

Journal of Cystic Fibrosis, 3 S1 S29


The European Cystic Fibrosis Conference, Birmingham, 2004

Current non-viral synthetic gene therapy vectors for the treatment of cystic fibrosis are limited by inefficient uptake to cells of the respiratory tract, leading to very low levels of gene transfer.

Electroporation has been used to dramatically increase gene transfer to a number of tissues. We are evaluating the use of electroporation to enhance gene transfer to the airway epithelia in the mouse lung model.

In ex vivo studies it was found that following delivery in naked pDNA, reporter gene expression could be increased by up to 500 fold depending on the combination of voltage and pulse length used. In vivo studies were performed by combining intranasal delivery of naked pCIKLux, (Lux reporter gene, CMVIE promoter and SV40 polyA) (100µg/150µl water) with a surgical procedure to expose the lung tissue for electroporation. Electroporation was carried out using the BTX ECMÆ830 Generator with 2-Needle electrodes with 5mm gap and Lux activity was assayed 24 hours later. Following electroporation at 200V/cm:20ms, Lux activity was 70 fold higher than naked pDNA alone (P=0.012).

When lungs were electroporated at 800V/cm:2ms, the Lux activity was 400 fold higher than plasmid DNA (P=0.008). To define the cell types and regions of the lungs affected, lungs were electroporated following delivery of pEGFP-N1 expressing green fluorescent protein. Reporter gene expression was observed mainly in the alveolar region of the lung, but electroporation resulted in many orders of magnitude more GFP positive cells than non-electroporated lungs. Studies are now underway to determine the duration of reporter gene expression following electroporation of the mouse lung.

The potential and practicalities of electroporating the lung airways of a large animal model, are also being investigated.