Use of Rational Design to Identify a Novel AAV8 variant that Transduces Ganglion cells with High Efficiency in mice

Abstract

Purpose :
Delivering drugs effectively to target cells, retinal pigment epithelial cells for example, poses a challenge in AAV mediated gene therapy for ophthalmic diseases. AAV vectors can be directly delivered into the subretinal space by subretinal injection, but this procedure requires high technical skills, advanced equipment, surgery requiring the use of surgical suite/operating room, and carries potential risks.
Intravitreal (IVT) injections are easier to administer and pose less risks, and can be performed in regular outpatient clinic. IVT injections will require high transduction efficiency of the AAV vector to target key cells. The purpose of the current study is to identify AAV capsid with high transduction efficiency to the retinal tissues through IVT injection.

Methods : We engineered capsids on the Variable Region VIII (VR-VIII) of AAV8. AAV8v120, an AAV variant, was found to have high transduction efficiency in mouse eye. The novel AAV capsid was tested by packaging an EGFP reporter gene inside. 21 days after intravitreal injection into eyes of the mice, retinal tissues were harvested and the transduction efficiencies and tropism were evaluated.

Results : The capsid showed 33.8-fold high transduction efficiency in retinal tissue, as determined by EGFP signal over the parental AAV8 vector. This capsid primarily transduced the ganglion cell.

Conclusions : We report an AAV8 derived engineered capsid with high transduction efficiency through IVT injection in mouse. The study extends the understanding of the AAV8 variant. The new capsid AAV8v120 holds potential for translational studies in gene therapy for the treatment of ocular diseases.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Fig.1 Cross-section and immunofluorescence (EGFP, Green) analyses of mice retina treated with IVT injection of AAV8-EGFP (left) and AAV8v120-EGFP (right).