Non-redundant role of a zinc-metallopeptidase in retinal homeostasis.

Abstract

Purpose : Our goal is to identify and study genes essential to retinal development and homeostasis using an unbiased forward genetics approach. Here we characterize a novel association involving a gene coding for a zinc-metallopeptidase.

Methods : We used a forward genetics screening pipeline (N-ethyl-N- nitrosourea (ENU) mutagenesis in C57BL/6J mice) to identify in an unbiased manner a non-redundant gene leading to changes in retinal optical coherence tomography (OCT). Targeting this gene using CRISPR/Cas9 technology is allowing us to further characterize the resulting phenotype.

Results : The nemeth phenotype was identified in 3 mice homozygous for a mutation in a zinc metallopeptidase. All 3 mice showed approximately 20% thinning of the outer nuclear layer (ONL; p = 8.1 x 10^-12). CRISPR-mutagenesis led to two founder mice, which are now being bred. We will first determine if we can corroborate the predicted phenotype of a retinal degeneration in these mutant mouse lines. We will then further characterize their retinal phenotype using fundus photography, OCT, electrophysiology, and immunohistochemistry.

Conclusions : Screening using ONL measurements allowed us to identify a novel potential gene-retinal phenotype association involving a gene coding for a Zn metallopeptidase. Metallopeptidases have a preference for cleaving peptides and particularly the end terminals of peptide chains. They participate in many major physiological processes, and their dysregulation is involved in multiple diseases. Our studies will help characterize the specific role of this particular metallopeptidase in retinal homeostasis.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.