Abstract
Purpose :
The Shumiya cataract rat (SCR) is a hereditary cataractous strain in which 66.7% of the animals develop lens opacity. Cataract appears in 10–11 week-old SCRs. Cataract onset is related to a combination of lanosterol synthase (Lss) and farnesyl diphosphate farnesyl transferase 1 (Fdft1) mutant alleles, which decrease the cholesterol levels in SCR lenses. However, the initiation mechanism of the lens opacity is poorly understood. Using a microarray-based approach, we studied the changes in gene expression during the precataractous stage of lenses in SCRs.
Methods :
All animal experiments were conducted in accordance with the Statement for the Use of Animals in Ophthalmic and Vision Research and the guidelines of the Committee of the Ethics of Animal Experiments at the Kanazawa Medical University. Five-week-old SCRs were used for microarray analysis and examined for histological analysis. Cataractous SCRs were distinguished by PCR detection of Lss mutation. To identify differential gene expression patterns of SCR lenses, lens epithelial cells (LECs) with capsules from cataractous and non-cataractous SCRs were isolated at 5 weeks of age. Total RNA was extracted from the lenses and labelled cDNA was hybridized with an Affimetrix rat gene 2.0 ST array. Changes in gene expressions were analyzed. Real-time PCR and western blot analysis were used to validate the microarray results.
Results :
Lens opacity was not observed in 5-week-old SCRs, but histological analysis revealed mild dysplasia of the anterior suture and poorly differentiated fiber cells at the bow region in SCRs. Expression of approximately 100 genes, such as major intrinsic protein of lens fiber (MIP, Aquaporin0), deoxyribonuclease II beta (Dnase2b), heat shock protein B1 (Hspb1) and crystallin,γ B,C,F were downregulated (0.07–0.5 fold) in rat LECs with cataract compared to those of controls. Expression of 6 genes, such as schlafen4 were upregulated (2.1-2.5 fold) in rat LECs with cataract compared to those of controls.
Conclusions :
These findings revealed the gene expression patterns during cataract formation of SCRs. Lss mutation may induce the downregulation of genes linked to lens fiber differentiation, leading to cataract in SCRs.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.