A cargo adaptor protein with an essential role in retinal health

Abstract

Purpose : To corroborate that a cargo adaptor protein is essential to retinal homeostasis and start exploring the mechanisms explaining its role in retinal physiology

Methods : Using an unbiased forward genetics approach to screen for genes associated to retinal fundus spot accumulation and retinal thinning we identified a gene of interest that codes for a cargo adaptor protein. We targeted this gene using CRISPR/Cas9 mutagenesis. The retina of the resulting mouse line was characterized using multiple protocols.

Results : The N-ethyl-N-nitrosourea (ENU) mutagenesis screen identified the bargain allele, which encodes a mutation in a cargo adaptor protein, as being associated to a decrease in outer retinal thickness (average decrease of 9% thickness, p = 3x10^-5). The phenotype seen in the forward genetics screen was recapitulated in a CRISPR-generated knock-in (KI) mouse line. These mice showed statistically significant thinning of the outer retina in Optical Coherence Tomography (OCT) compared to the control group at 2 months of age (p=0.005). Outer nuclear layer (ONL) thinning and increased reflectivity of the outer retina in OCT images were detected at 6 months of age (p=0.02 and p=0.0003, respectively). Analysis of fundus photographs demonstrated an increased number of fundus spots in the KI mice (p=0.01). Detailed evaluation of histological and electron microscopy specimens at 10 months of age will also be shown.

Conclusions : A forward genetics screening protocol allowed us to identify a novel association of a cargo adaptor protein to retinal homeostasis.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.