Abstract
Purpose:
We identified CAPN5 (calpain-5) as the causative gene for autoimmune uveitis in patients with Autosomal Dominant Neovascular Inflammatory Vitreoretinopathy (ADNIV). To understand the molecular genetic mechanisms of ADNIV and develop a preclinical model, retinal Capn5 was studied in mice.
Methods:
Primary, secondary, and tertiary protein alignments were created with Geneious Pro Yasara Structure software. DNA sequencing, immunohistochemistry, and histology was performed using standard methods. A lentiviral vector expressing green fluorescent proteins (GFP) under a rhodopsin promoter was injected into the subretinal space of perinatal mice. Lentiviral expression was determined by autofluorescence imaging, and expression phenotypes were analyzed through six months of age using electroretinography and histological assessment.
Results:
Mouse calpain-5 protein showed high homology to its human ortholog with over 80% sequence identity that included the ADNIV mutant residues. Three-dimensional protein modeling of calpain-5 to other calpains revealed a high structural homology. Expression of Capn5 was detected in a mouse photoreceptor-specific cDNA library. In mouse photoreceptor cells there was strong calpain-5 protein expression in the inner and outer segments of both rods and cones, which correlated with human eye expression. Phenotyping of Capn5 knockout mice did not show eye abnormalities. To study a gain of Capn5 function effect, a photoreceptor-specific expression lentiviral vector was designed and injected into the subretinal space of perinatal mice. Live imaging of a GFP reporter showed good uptake and distribution throughout the retina. Electroretinography and histological examination supported the use of this vector with CAPN5 mutants.
Conclusions:
Taken together, our studies suggest that genetic models of ADNIV can be developed in the mouse. There are a very limited number of animal models for uveitis, ocular neovascularization, and intraocular fibrosis, and a Capn5-ADNIV mouse model may help address this gap.
Keywords: 539 genetics •
746 uveitis-clinical/animal model •
688 retina