Establishing novel AAV gene editing for Usher Syndrome

Project Aim

To establish proof-of-concept for adeno associated viral (AAV) vectors gene editing treatments designed specifically for genetically confirmed Usher Syndrome subtype 1 Australian patients.

Project Summary

In this study, we will evaluate efficacy for Usher 1B and 1F gene therapy using genome editing. We have the ability to generate the light-sensing photoreceptor cells for testing of these therapies in the patients’ own cells, by converting their blood or skin cells into induced pluripotent stem cells (iPSC) and then generating mini-retinae, retinal organoids. We have generated retinal organoids from Usher patients and use these to test whether therapies reverse their specific genetic defect. Here these retinal organoids will be treated using a novel approach which will replace the region of the gene that encompasses the mutation in a permanent manner. This process requires two viral vectors, one to deliver the gene editing machinery and another to deliver the correct region of the genome. The use of two viral vectors entering the cells simultaneously is inefficient and thus we will test the use of lipid nanoparticles (LNPs) to deliver the Cas9 instead of a viral vector. This also avoids long term exposure to Cas9 in the cells, thus reducing unwanted editing of other genome parts.

Expected outcomes

This project is expected to (1) generate pre-clinical data and establish efficacy for AAV gene editing to treat a number of Usher patients and other patients with common IRDs; (2) provide more access to clinical trials by developing gene editing tools that are suitable and efficacious to use in clinical trials; (3) lead to new health technologies embedded in health practice: this study uses stem cells and its derivative organoids which, as new health technologies, will be used for precision medicine functional assays.