Optogenetic therapy: high spatiotemporal resolution and pattern discrimination compatible with vision restoration in non-human primates

Grégory Gauvain ,Didier Pruneau ,Elena Brazhnikova ,Ryad Benosman ,Deniz Dalkara ,José‐Alain Sahel ,Himanshu Akolkar ,Pierre Pouget ,Fabrice Arcizet ,Stéphane Bertin ,Antoine Chaffiol ,Claire-Maëlle Fovet ,Mélissa Desrosiers ,Joël Chavas ,Anne Douar ,Romain Caplette ,Olivier Marre ,J Demilly ,C Jaillard ,Philippe Hantraye ,Mina A Khoei ,Valérie Forster ,Jens Duebel ,Serge Picaud

doi:10.1038/s42003-020-01594-w

Abstract

Vision restoration is an ideal medical application for optogenetics, because the eye provides direct optical access to the retina for stimulation. Optogenetic therapy could be used for diseases involving photoreceptor degeneration, such as retinitis pigmentosa or age-related macular degeneration. We describe here the selection, in non-human primates, of a specific optogenetic construct currently tested in a clinical trial. We used the microbial opsin ChrimsonR, and showed that the AAV2.7m8 vector had a higher transfection efficiency than AAV2 in retinal ganglion cells (RGCs) and that ChrimsonR fused to tdTomato (ChR-tdT) was expressed more efficiently than ChrimsonR. Light at 600 nm activated RGCs transfected with AAV2.7m8 ChR-tdT, from an irradiance of 1015 photons.cm−2.s−1. Vector doses of 5 × 1010 and 5 × 1011 vg/eye transfected up to 7000 RGCs/mm2 in the perifovea, with no significant immune reaction. We recorded RGC responses from a stimulus duration of 1 ms upwards. When using the recorded activity to decode stimulus information, we obtained an estimated visual acuity of 20/249, above the level of legal blindness (20/400). These results lay the groundwork for the ongoing clinical trial with the AAV2.7m8 - ChR-tdT vector for vision restoration in patients with retinitis pigmentosa.

Highlights

Vision restoration is an ideal medical application for optogenetics, because the eye provides direct optical access to the retina for stimulation
We investigated whether the native ChR protein and the ChrimsonR-tdTomato (ChR-tdT) fusion protein were produced in similar amounts in primate retinal ganglion cells (RGCs)
The four selected constructs (AAV2 and AAV2.7m8 vectors encoding either ChR or ChrimsonR fused to tdTomato (ChR-tdT)) were each injected into four eyes, at the same concentration (5 × 1011 vg/eye); eight animals in total were used for this experiment (Supplementary Table S1)

Summary

Introduction

Vision restoration is an ideal medical application for optogenetics, because the eye provides direct optical access to the retina for stimulation. When using the recorded activity to decode stimulus information, we obtained an estimated visual acuity of 20/249, above the level of legal blindness (20/400) These results lay the groundwork for the ongoing clinical trial with the AAV2.7m8 - ChR-tdT vector for vision restoration in patients with retinitis pigmentosa. Using the responses to moving bars and letters generated on a multielectrode array, we obtained an estimated theoretical visual acuity of 20/249, which is above the threshold for legal blindness These characterizations of the visual response in the non-human primate retina paved the way for the ongoing clinical trial with the AAV2.7m8-ChrimsonR-tdT vector for vision restoration in patients with retinitis pigmentosa

Methods

Results

Discussion

Conclusion