title: CAPN5 mutation in hereditary uveitis: the R243L mutation increases calpain catalytic activity and triggers intraocular inflammation in a mouse model.
abstract: A single amino acid mutation near the active site of the CAPN5 protease was linked to the inherited blinding disorder, autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV, OMIM #193235). In homology modeling with other calpains, this R243L CAPN5 mutation was situated in a mobile loop that gates substrate access to the calcium-regulated active site. In in vitro activity assays, the mutation increased calpain protease activity and made it far more active at low concentrations of calcium. To test whether the disease allele could yield an animal model of ADNIV, we created transgenic mice expressing human (h) CAPN5(R243L) only in the retina. The resulting hCAPN5(R243L) transgenic mice developed a phenotype consistent with human uveitis and ADNIV, at the clinical, histological and molecular levels. The fundus of hCAPN5(R243L) mice showed enhanced autofluorescence (AF) and pigment changes indicative of reactive retinal pigment epithelial cells and photoreceptor degeneration. Electroretinography showed mutant mouse eyes had a selective loss of the b-wave indicating an inner-retina signaling defect. Histological analysis of mutant mouse eyes showed protein extravasation from dilated vessels into the anterior chamber and vitreous, vitreous inflammation, vitreous and retinal fibrosis and retinal degeneration. Analysis of gene expression changes in the hCAPN5(R243L) mouse retina showed upregulation of several markers, including members of the Toll-like receptor pathway, chemokines and cytokines, indicative of both an innate and adaptive immune response. Since many forms of uveitis share phenotypic characteristics of ADNIV, this mouse offers a model with therapeutic testing utility for ADNIV and uveitis patients.
authors.affiliation: Barbara and Donald Jonas Laboratory of Stem Cells and Regenerative Medicine and Bernard and Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, Institute of Human Nutrition, College of Physicians and Surgeons.
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Wert
authors.affiliation: Department of Pediatrics and Neurology.
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Bassuk
authors.affiliation: Barbara and Donald Jonas Laboratory of Stem Cells and Regenerative Medicine and Bernard and Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute.
authors.forename: Wen-Hsuan
authors.initials: WH
authors.lastname: Wu
authors.affiliation: Department of Biochemistry, Protein Crystallography Facility.
authors.forename: Lokesh
authors.initials: L
authors.lastname: Gakhar
authors.affiliation: Omics Laboratory and Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA.
authors.forename: Diana
authors.initials: D
authors.lastname: Coglan
authors.affiliation: Omics Laboratory and Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA.
authors.forename: MaryAnn
authors.initials: M
authors.lastname: Mahajan
authors.affiliation: Department of Pediatrics and Neurology.
authors.forename: Shu
authors.initials: S
authors.lastname: Wu
authors.affiliation: Protein Crystallography Facility, Omics Laboratory and.
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.affiliation: Herbert Irving Comprehensive Cancer Center.
authors.forename: Chyuan-Sheng
authors.initials: CS
authors.lastname: Lin
authors.affiliation: Barbara and Donald Jonas Laboratory of Stem Cells and Regenerative Medicine and Bernard and Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, Institute of Human Nutrition, College of Physicians and Surgeons, Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA, mahajanlab@gmail.com gene.targeting@gmail.com.
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Tsang
authors.affiliation: Omics Laboratory and Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA mahajanlab@gmail.com gene.targeting@gmail.com.
authors.forename: Vinit B
authors.initials: VB
authors.lastname: Mahajan
mesh_terms: D000818:Animals; D002154:Calpain / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D030342:Genetic Diseases, Inborn / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007249:Inflammation; D051379:Mice; D008822:Mice, Transgenic; D014605:Uveitis / Q000235:genetics / Q000378:metabolism / Q000473:pathology
chemical_list: D002154:Calpain; C494426:Capn5 protein, human; C403235:Capn5 protein, mouse