Periodic Reporting for period 3 - EYEGET (Gene therapy of inherited retinal diseases)
Période du rapport: 2020-01-01 au 2021-06-30
EYEGET (EYE GEne Therapy) exploits the versatile and safe AAV platform to overcome the remaining challenges in retinal gene therapy and make this strategy widely applicable to treat genetic blindness:
1. Many recessive IRDs require the transfer of large genes whose size exceeds AAV cargo capacity. Objective 1 of this proposal is to investigate the efficacy of co-injection of multiple AAVs each carrying one part of a large gene which reassemble in target cells.
2. Several common forms of dominant IRDs are due to gain-of-function mutations that result in production of toxic proteins. Objective 2 uses genome editing with CRISPR-Cas9 to either knock-down or correct these mutant alleles.
3. In several recessive and dominant IRDs accumulation of toxic products results in photoreceptor cell death. To address these disorders, we propose to use AAV-mediated gene transfer to induce clearance of these toxic products (Objective 3).
4. In vivo gene therapy can not be applied to late stage IRDs when the majority of photoreceptor cells are lost. In Objective 4 we propose to investigate a novel method to obtain in a dish photoreceptors that can be transplanted in the diseased retinas, with or without previous ex vivo AAV-mediated correction.
We have also observed that genome editing can occur in photoreceptors of mice and pigs and we are currently characterizing whether this has therapeutic relevance in animal models. Similarly, we are testing the efficacy of AAV vectors that express key inducers of cellular clearance and autophagy to enhance degradation of toxic proteins in IRDs.
Finally, we have developed human 3D retina which contain photoreceptor-like cells that we are considering for cell replacement in diseased retinas as well as to model human IRDs in a dish.