Abstract
Introduction: :
Objectives: To demonstrate retinal function/vision recovery following non-viral mediated gene transfer to the retina facilitated by phi C31 integrase.
Methods: :
Cohorts of neonatal (3-5 day old) RPE65-/- mice received subretinal injections of a two plasmid cocktail, consisting of a vector with the wild-type RPE65 transgene with the attachment site B sequence (pCMV.RPE65.attB) and the other encoding the integrase enzyme (pCMV.Int) into the right eye. Contralateral left eyes were left un-injected. Additional cohorts of control animals received right eye subretinal injections of pCMV.eGFP.attB or pCMV.RPE65.attB with and without pCMV.Int. Each eye received 1.5 ul of vector, with subsequent directional electroporation toward the retinal pigment epithelial layer. At 28 days post injection, animals underwent full field electroretinograms (ERG) and optokinetic nystagmus response (OKR) testing.
Results: :
Eyes injected with wildtype RPE65 exhibited ERGs with robust a-waves, whereas contralateral eyes showed flat ERGs. OKR test results reflected the ERG results, as treated eyes had significant OKR responses. Control animals had no restoration of retinal/visual function as measured by ERG or OKR. No gross inflammation was appreciated.
Conclusions: :
Phi C31 integrase can facilitate gene transfer to murine retinal pigment epithelial cells in vivo, promoting functional recovery of retinal/visual function as measured by ERG and OKR. Further optimization will be needed to increase efficiency of transduction, document stability and for application to other forms of retinal degeneration.
Keywords: gene transfer/gene therapy • retinal degenerations: cell biology • genetics