Abstract
Purpose: :
Adenovirus (Ad) vectors are efficient gene delivery vehicles and are widely used in pre-clinical and clinical gene therapies. The aim of this study was to evaluate the transduction efficiency and localization in the eye of Ad vectors for serotypes 5, 28 and 35.
Methods: :
To determine the time course of luciferase activity, mice received a single intravitreal injection of Ad vector containing the construct expressing luciferase. Naïve animals or animals with intraocular injection of empty adenoviral vectors served as negative controls. Eyes were harvested and assayed for luciferase activity. To assess cell transduction localization, eyes with intravitreal or subretinal injection of Ad vector expressing green fluorescent protein (GFP) were cryosectioned. Specimens were counter-stained with propidium iodide and examined by fluorescence light microscope.
Results: :
Intravitreal injection induced iris, corneal endothelium, and trabecular cells transduction with all vectors. Of the vectors, Ad5 vectors showed the strongest GFP expression among the tested serotypes. This result is consistent with luciferase activity assays. Subretinal injection of Ad5 vector without the RGD motif induced GFP expression in RPE cells. In contrast, Ad5 vector with the RGD motif transduced mainly in photoreceptor cells via subretinal delivery. The Ad28 vector transduced both photoreceptors and RPE cells. Ad35 vectors transduced both cells more efficiently when delivered subretinally.
Conclusions: :
Cell transduction localization differed somewhat with each serotype of Ad vector and injection technique. Intravitreous injection showed iris, corneal endothelium, and trabecular cell transduction for all serotypes. Subretinal injection with Ad5 vector showed RPE transduction, and Ad5 vectors with the RGD motif showed the strongest transduction within photoreceptors. Ad35 vectors transduced both photoreceptors and RPE cells efficiently when delivered subretinally. These data demonstrate that Ad based gene transfer vectors can target distinct cell types.
Keywords: gene transfer/gene therapy • adenovirus • transgenics/knock-outs