Electroporation enhances reporter gene expression following delivery of naked plasmid DNA to the lung.
BACKGROUND
Existing methods of non-viral airway gene transfer suffer from low levels of efficiency. Electroporation has been used to enhance gene transfer in a range of tissues. Here we assess the usefulness of electroporation for enhancing gene transfer in the lungs of mice and sheep.


METHODS
Naked plasmid DNA (pDNA) expressing either luciferase or green fluorescent protein (GFP) was delivered to mouse lungs by instillation. Following surgical visualisation, the lungs were directly electroporated and the level and duration of luciferase activity was assessed and cell types that were positive for GFP were identified in lung cryosections. Naked pDNA was nebulised to the sheep lung and electrodes attached to the tip of a bronchoscope were used to electroporate airway segment bifurcations, Luciferase activity was assessed in electroporated and control non-electroporated regions, after 24 h.


RESULTS
Following delivery of naked pDNA to the mouse lung, electroporation resulted in up to 400-fold higher luciferase activity than naked pDNA alone when luciferase was under the control of a cytomegalovirus (CMV) promoter. Following delivery of a plasmid containing the human polyubiquitin C (UbC) promoter, electroporation resulted in elevated luciferase activity for at least 28 days. Visualisation of GFP indicated that electroporation resulted in increased GFP detection compared with non-electroporated controls. In the sheep lung electroporation of defined sites in the airways resulted in luciferase activity 100-fold greater than naked pDNA alone.


CONCLUSIONS
These results indicate that electroporation can be used to enhance gene transfer in the lungs of mice and sheep without compromising the duration of expression.
Pringle
Ian A
IA
GeneMedicine Research Group, Nuffield Department of Clinical Laboratory Sciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
McLachlan
Gerry
G
Collie
David D S
DD
Sumner-Jones
Stephanie G
SG
Lawton
Anna E
AE
Tennant
Peter
P
Baker
Alison
A
Gordon
Catherine
C
Blundell
Richard
R
Varathalingam
Anusha
A
Davies
Lee A
LA
Schmid
Ralph A
RA
Cheng
Seng H
SH
Porteous
David J
DJ
Gill
Deborah R
DR
Hyde
Stephen C
SC
D000818:Animals; D018274:Electroporation; D015870:Gene Expression; D018014:Gene Transfer Techniques; D017930:Genes, Reporter / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D007700:Kinetics; D008156:Luciferases / Q000235:genetics; D008168:Lung / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D010957:Plasmids / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012756:Sheep
D049452:Green Fluorescent Proteins; D008156:Luciferases