Substantial restoration of night vision in adult mice with congenital stationary night blindness
Juliette Varin, Nassima Bouzidi, Grégory Gauvain, Corentin Joffrois, Mélissa Desrosiers, Camille Robert, Miguel Miranda de Sousa Dias, Marion Neuillé, Christelle Michiels, Marco Nassisi, José‐Alain Sahel, Serge Picaud, Isabelle Audo, Deniz Dalkara, Christina Zeitz
Abstract
Complete congenital stationary night blindness (cCSNB) due to mutations in TRPM1 , GRM6 , GPR179 , NYX , or leucine-rich repeat immunoglobulin-like transmembrane domain 3 ( LRIT3 ) is an incurable inherited retinal disorder characterized by an ON-bipolar cell (ON-BC) defect. Since the disease is non-degenerative and stable, treatment could theoretically be administrated at any time in life, making it a promising target for gene therapy. Until now, adeno-associated virus (AAV)-mediated therapies lead to significant functional improvements only in newborn cCSNB mice. Here we aimed to restore protein localization and function in adult Lrit3 −/ − mice. LRIT3 localizes in the outer plexiform layer and is crucial for TRPM1 localization at the dendritic tips of ON-BCs and the electroretinogram (ERG)-b-wave. AAV2-7m8- Lrit3 intravitreal injections were performed targeting either ON-BCs, photoreceptors (PRs), or both. Protein localization of LRIT3 and TRPM1 at the rod-to-rod BC synapse, functional rescue of scotopic responses, and ON-responses detection at the ganglion cell level were achieved in a few mice when ON-BCs alone or both PRs and ON-BCs, were targeted. More importantly, a significant number of treated adult Lrit3 −/− mice revealed an ERG b-wave recovery under scotopic conditions, improved optomotor responses, and on-time ON-responses at the ganglion cell level when PRs were targeted. Functional rescue was maintained for at least 4 months after treatment.