Abstract
Purpose :
Gene therapy holds promise for the development of treatments for the inherited retinal diseases (IRD). Adeno-associated virus (AAV) has emerged as the most commonly used gene therapy vectors for treating the IRD. The main injection route into retina includes intravitreal injection and subretinal injection. Intravitreal injection is a relatively safe and easy method. However, the detailed transduction profiles of AAV serotypes and their capsid mutants in retina via intravitreal injection have not been reported.
Methods :
In this study, we selected AAV 2, 6, 8 and 9 serotypes and created the single or multiple amino acid mutants of capsid to examine the transduction profile of the vectors in the mouse retina following intravitreal injection.
Results :
Compared with the wild type AAV2, expression efficiency of the EGFP reporter gene of rAAV2-Y444F and rAAV2-tYF in the retina was increased. rAAV2 and rAAV2-Y444F mainly targeted retinal ganglion cells while rAAV2-tYF had obvious EGFP expression in RPE. rAAV6 was showed to target retinal ganglion cells, while EGFP expression of rAAV6-YFTV could be seen in the whole retinal tissue including RPE. rAAV8 and rAAV8-Y733F had preference for photoreceptors and RPE. rAAV8-Y733F had higher EGFP expression efficiency than rAAV8, while rAAV8-tYF g EGFP expression efficiency was lower than rAAV8 and rAAV8-Y733F. Genes delivered with rAAV9, rAAV9-Y446F and rAAV9-tYF were all expressed in RPE and photoreceptors. rAAV9-tYF was showed to be more efficient in RPE. Two weeks after the injection, all vectors had strong gene expression. rAAV2 gene expression in the ganglion cells was very stable and rAAV6-S663L gene expression which could be seen across the retinal tissue was very stable too three months after the injection. Meanwhile, the transduction efficiency of rAAV8-tYF and rAAV9-tYF was greatly enhanced three months later. On the other hand, EGFP expression of rAAV2-tYF and rAAV6-YFTV in RPE seemed unstable.
Conclusions :
Our study provides the comprehensive profile of AAV gene expression in retina following intravitreal injection. It could be very useful for the selection of AAV vectors for human IRD gene therapy.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.