Tropism of AAV Vectors in Photoreceptor-Like Cells of Human iPSC-Derived Retinal Organoids

Gene therapy treatments for inherited retinal diseases have developed rapidly in the past decade, with dozens of clinical trials for different disorders currently ongoing. The vast majority of such trials use adeno-associated viral (AAV) vectors to deliver a transgene of interest. All vectors undergo preclinical testing that typically involves a combination of in vitro and in vivo studies to confirm not only that the vectors generate the desired expression products but also that they offer a degree of efficacy and an absence of toxicity.

To expand the use of human retinal organoids from induced pluripotent stem cells (iPSCs) as an in vitro model of the retina for assessing gene therapy treatments, it is essential to establish efficient transduction. To date, targeted transduction of the photoreceptor-like cells of retinal organoids with AAV vectors has had varied degrees of success, which we have looked to improve in this study.

Retinal organoids were differentiated from iPSCs of healthy donors and transduced with reporter AAV containing different transgenes. A number of capsid variants were also assessed. At 27 days post-transduction, retinal organoids were assessed for reporter expression and viability.

Reliable transduction of the photoreceptor-like cells of retinal organoids was readily achieved. When using a CAG-driven transgene, transduction of a broad range of cell types is observed, and GRK1 transgenes provide a more restricted expression profile locating to the outer layer of photoreceptor-like cells of retinal organoids.

This study expands the AAV capsid and transgene options for preclinical testing of gene therapy in iPSC-derived human retinal organoids.

Find out more about how our retinal organoids and RPE models can be used for preclinical testing of gene therapy