A Mouse Model of Schnyder Corneal Dystrophy with the N100S Point Mutation

Abstract

Purpose : Schnyder corneal dystrophy (SCD) is an autosomal dominant disease in humans, which is caused by mutations in the Ubia prenyltransferase domain containing 1 (UBIAD1) gene in chromosome 1 p36 and is characterized by progressive corneal opacification resulting from abnormal deposition of cholesterol and phospholipids. To investigate the pathogenesis and develop therapeutic regimens for SCD, we generated a mutant mouse line carrying a N100S mutation in Ubiad1, which mimics human N102S mutation.

Methods : The Ubiad1^N100S mouse line was generated by the CRISPR/Cas9 genome editing technique. Twenty corneas from ten individual mice of the genotypes Ubiad1^N100S/N100S, Ubiad1^N100/WT and wild type (WT) lines were subjected to in vivo confocal microscopy (Heidelberg Retinal Tomograph-HRTII Rostock Cornea Module) at the age of 6 weeks. Quantitative analysis of deposits based on in vivo confocal microscopic images was conducted using Image J software. Filipin staining was performed on cryosections of Ubiad1^N100S/N100S, Ubiad1^N100S/WT and WT mice to determine the cholesterol deposition in cornea. Ubiad1^N100S/N100S, Ubiad1^N100S/WT and WT mice corneas were examined with electron microscopy.

Results : The Ubiad1^N100S point mutation mouse line has been successfully created using the CRISPR/Cas9 technique. Homozygous Ubiad1^N100S/N100S and heterozygous Ubiad1^N100S/WT mice are fertile and do not manifest apparent pathology except for anterior corneal. Filipin staining demonstrated elevated cholesterol in cornea of Ubiad1^N100S/N100S and Ubiad1^N100S/WT Electron microscopy revealed mitochondrial degeneration in the epithelium and keratocytes. These observations implied that the pathogenesis of SCD might be related to cholesterol accumulation and mitochondrial regulation of lipid metabolism.

Conclusions : The Ubiad1^N100S mouse provides a promising animal model of SCD which may facilitate understanding SCD pathogenesis and development of therapeutic regimens for SCD.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.