Abstract
Purpose :
Suprachoroidal gene transfer provides a new noninvasive approach and we have previously demonstrated widespread expression in photoreceptors and RPE after suprachoroidal injection of AAV8.GFP and AAV9.GFP, but not AAV2.GFP. This study was designed to assess the expression of AAV2tYF and AAV5 vectors after suprachoroidal injection.
Methods :
Norway Brown rats (n=65) had suprachoroidal injection of 7.8 x 109 GC of AAV2tYF-CBA-hGFP, 7.8 x 109 GC of AAV2tYF-GRK1-hGFP, 7.8 x 109 GC of AAV5-GRK1-hGFP, or 6.87 x 109 GC of AAV2-CBA-hGFP. At 2 or 4 weeks after injection, retina and RPE/choroid flat mounts or ocular sections were examined by fluorescence microscopy. Homogenates of RPE/choroid and retinas were used to measure total protein and GFP protein was measured by ELISA.
Results :
Each of the vectors reached peak expression by 2 weeks after injection except AAV2tYF-GRK1-hGFP which showed some further increase between 2 and 4 weeks. Compared with AAV2-CBA-hGFP, AAV2tYF-CBA-hGFP showed more extensive and higher expression of GFP, extending approximately 1/4 circumference of the eye in the RPE and all layers of the retina. Expression was limited to photoreceptors (inner segments, outer segments and some cell bodies) after suprachoroidal injection of AAV2tYF-GRK1-GFP and AAV5tYF-GRK1-GFP, and extending around 1/4 and 1/6 the circumference of the eye, respectively. The mean (± SEM) level of GFP (ng/mg protein) in retina for each of the vectors is shown in Table 1.
Conclusions :
AAV2tYF-CBA provides much greater transduction after suprachoroidal injection than AAV2-CBA. The extent of expression is less than that previously seen with AAV8 and AAV9, but provides more transduction of inner retinal cells. Compared with AAV5-GRK1, AAV2tYF-GRK1 provides greater and more extensive transduction of photoreceptors.
This is a 2020 ARVO Annual Meeting abstract.