ALDH3A1 PROTECTS CORNEA AND LENS AGAINST UVB–INDUCED 4–HNE–PROTEIN ADDUCT FORMATION

Abstract

Abstract: : Purpose:ALDH3A1is an NAD(P)+–dependent aldehyde dehydrogenase expressed at high concentration in the corneal epithelium of several mammalian species, including human. We have recently shown that ALDH3A1 protects human corneal epithelial cells against UV– and 4–HNE– induced apoptosis, supporting the notion that this crystallin plays a significant role in cellular defense mechanisms against oxidative damage. The aim of this study was to investigate the protective effects of ALDH3A1 in cornea and lens of mice exposed to UVB. Methods: Transgenic Aldh3a1(–/–) knockout mice and their wild–type counterparts were exposed to UVB irradiation at 0, 0.1, 0.2, and 0.5 J/cm². The 4–HNE–protein adduct formation was assayed in cornea and lens by Western blot analysis using polyclonal Ab against KLH–4HNE. Results: Our data showed that several 4–HNE–adducted proteins were detected 12 hrs after UVB irradiation in the cornea and lens of both Aldh3a1(–/–) mice and wild–type mice. These 4–HNE–adducted proteins were not present in unexposed wild–type animals, however some of these adducts were detected in cornea and lens of untreated Aldh3a1(–/–) mice. On the other hand, the 4–HNE–protein adduct formation was more profound in UVB exposed Aldh3a1(–/–) mice than in wild–type mice. Collectively, these data show for the first time increased 4–HNE–adducted proteins in mouse cornea and lens after exposure to UVB, which are more pronounced in ALDH3A1–deficient mice.Conclusions: These results provide direct evidence that ALDH3A1 protects both cornea and lens against UVB–induced formation of 4–HNE–protein adducts.

Keywords: cornea: basic science • metabolism • transgenics/knock–outs