Institution: University of California Berkeley
Poster Title: Screening Novel AAV Variants for Efficient AAV Transduction via Intravitreal Injection for AMD Gene Therapy
Abstract: Retinal degeneration is often driven by mutations in the outer retinal layer, primarily affecting the retinal pigment epithelium (RPE) and photoreceptor cells. Although Adeno-Associated Virus (AAV) vectors show promise as a therapeutic approach, the conventional subretinal delivery method is invasive and requires multiple reinjections over time, posing significant challenges for widespread application. This study aims to identify AAV variants capable of efficiently transducing RPE cells through the less invasive and more sustainable intravitreal injection method. We engineered two AAV Serotype 2 libraries, 7mer and LoopSwap453, designed to modify the capsid's outer surface structure, which influences its binding capabilities to different retinal components. These libraries consist of 1.28 × 10? and 4.10 × 10¹? variants, respectively. To date, AAV2.7mer has been intravitreally injected into three species, followed by posterior eye cup harvesting. DNA extraction and Next-Generation Sequencing (NGS) were used to quantify the prevalence of each variant capable of transducing the outer retinal layers. Through a streamlined selection process, we identified top-performing AAV variants, which were subsequently repackaged with a ubiquitous promoter and GFP transgene to assess transduction efficiency. Our data indicate that upon repackaging with GFP, the top third variant from the initial AAV2.7mer screening, which we called Variant 3 (Var3) , proved to effectively transduce RPE cells. Currently, AAV2.LS453 trials have identified top-performing variants in mice and are awaiting repackaging. We anticipate similar results with AAV2.LS453 variants optimized for selective and efficient RPE transduction.