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Epha2 genotype influences ultraviolet radiation induced cataract in mice

Citation

Dave, A and Craig, JE and Skrzypiec, K and Quinn, S and Barnes, M and Di Girolamo, N and Mackey, DA and Burdon, KP and de Iongh, RU and Sharma, S, Epha2 genotype influences ultraviolet radiation induced cataract in mice, Experimental Eye Research, 188 Article 107806. ISSN 0014-4835 (2019) [Refereed Article]

Copyright Statement

Copyright 2019 Elsevier Ltd.

DOI: doi:10.1016/j.exer.2019.107806

Abstract

Age-related cataract is the major cause of blindness worldwide. Both genetic and environmental factors contribute to the disease. Genetic variation in the Ephrin type-A receptor 2 (EPHA2) gene is associated with the risk of age-related cataract in multiple populations, and exposure to ultraviolet-B (UV-B) radiation is a well-established risk factor for the disease. Epha2 knockout and UV-B radiation independently lead to cataract in mice, and UV-B radiation reportedly alters EPHA2 expression in cultured cells. We hypothesised that an interaction between UV-B radiation exposure and Epha2 signalling may influence cataract development. To test this hypothesis, 5-week-old Epha2+/+ and Epha2+/- mice (n = 8 per group) were exposed to repeated below-threshold doses of UV-B radiation (0.0125-0.05 J/cm2), before development of Epha2-mediated cataract. Cataract development was monitored after termination of exposure and at least one month later. Histological analysis of exposed and unexposed lenses was performed to assess pathological changes, and gene expression analysis to investigate the mechanism underlying cataract. Both Epha2+/+ and Epha2+/- mice developed UV-B dose-dependent anterior polar cataract; cataract severity in both genotypes of mice exposed to either 0.025 or 0.05 J/cm2 UV-B was significantly higher than that in matched unexposed mice (p < 0.05). Histological analysis of lenses of both genotypes of mice exposed to 0.025 or 0.05 J/cm2 UV-B radiation consistently revealed disruption of the lens architecture. A month after the exposure, cataract severity increased in Epha2+/+ mice treated with the highest dose of UV-B radiation (p = 0.03) but remained unchanged in Epha2+/- mice. Gene expression analysis of lenses of both genotypes of mice showed significant upregulation of the cell proliferation marker Mki67 in Epha2+/+ (p = 0.036) but not in Epha2+/- mice exposed to the highest dose of UV-B radiation compared to matched unexposed mice. In conclusion, this study suggests that repeated exposure to doses of UV-B radiation lower than the single minimum dose required for inducing cataract leads to cataract in wild-type and Epha2 heterozygous knockout mice. Furthermore, this study indicates, for the first time, a potentially favourable effect of partial Epha2 deficiency against UV radiation-induced damage in the lens.

Item Details

Item Type:Refereed Article
Keywords:age-related cataract, Epha2, gene-environment interaction, histological analysis, molecular mechanism, mouse model, UV-B radiation
Research Division:Medical and Health Sciences
Research Group:Ophthalmology and Optometry
Research Field:Ophthalmology
Objective Division:Health
Objective Group:Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:Hearing, Vision, Speech and Their Disorders
UTAS Author:Mackey, DA (Professor David Mackey)
UTAS Author:Burdon, KP (Professor Kathryn Burdon)
ID Code:135235
Year Published:2019
Deposited By:Menzies Institute for Medical Research
Deposited On:2019-10-08
Last Modified:2019-11-11
Downloads:0

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