Abstract
Purpose :
Current gene therapy treatments for ocular diseases relies largely on the use of subretinal injections for treatment of outer nuclear layer cells of interest. While subretinal injections allow for the efficient transduction of retinal cells at the site of the injection, there is a significant risk that these injections can further damage retinas with compromised integrity. Previous studies have shown promise for the use of mutated adeno-associated virus (AAV) capsids that are capable of outer nuclear layer cell transduction following intravitreal injections.
Methods :
In order to directly compare previously published capsid mutants to one another, other commonly used capsids, and serotypes 1 - 11, we utilize a viral DNA/RNA barcoding approach established by our lab. In this approach, AAV capsids derived from different serotypes and mutants can be identified by DNA barcodes unique to each AAV capsid. These barcodes are contained in viral genomes and also expressed as RNA barcodes following cellular transduction. As each AAV capsid strain has a unique viral genome, a mass transduction of all AAV strains can be conducted in order to directly compare transduction levels. Eyes are harvested ~4-6 weeks following intravitreal injections. Total DNA and RNA are extracted from the retina as a whole, or specific subsets of cells and subjected to the AAV Barcode-Seq analysis that enables us to analyze a vast number of AAV capsids for cellular transduction. This study will initially include male and female C57BL/6J mice and adult pigmented rabbits.
Results :
Currently, 4 male C57BL/6J mice have been injected intravitreally with between 1.5 and 9x109 vg bilaterally.
Conclusions :
Injections were well tolerated and vector was effectively delivered. The use of our barcoded vector library approach will allow for simultaneous evaluation of up to hundreds of mutant capsids in order to identify novel capsid mutants most effective at transduction of retinal cells following intravitreal injection. This approach will considerably benefit the field of AAV based gene therapy by increasing our knowledge of key amino acids involved in the transduction of the retina.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.