SERPINA3K ameliorates the corneal oxidative injury induced by 4-hydroxynonenal

Abstract

PURPOSE. We previously demonstrated that SERPINA3K has anti-inflammatory, antiangiogenic, and antioxidant effects in corneas. Here we further investigated the effects of SERPINA3K on the corneal oxidant injury setting recently developed and induced by 4-hydroxynonenal (4-HNE). METHODS. We applied the 4-HNE–induced corneal oxidant stress in cultured human corneal epithelial (HCE) cells in vitro and to the cornea of rats in vivo. The following experiments were conducted: cell counting kit 8 assay to detect cell viability; quantitative real-time PCR assay; Western blotting and immunofluorescent staining to measure gene expressions or protein levels of key reactive oxygen species (ROS)–associated factors (3-nitrotyrosine [3-NT]; nicotinamide adenine dinucleotide phosphate [NADPH]–oxidase 4 [NOX4]; superoxide dismutase [SOD]); catalase and nuclear factor [erythroid-derived 2]–like 2 [NRF2]); as well as main factors of the Wnt/β-catenin signaling pathway (p-LRP6, β-catenin and transcription factor 4 [TCF4]); histologic staining; and TUNEL staining to examine sections of rat corneas. RESULTS. We found that SERPINA3K concentration dependently protected cell viability, decreased levels of ROS marker 3-NT, suppressed NOX4, and upregulated SOD and catalase. Furthermore, SERPINA3K inhibited the activation of the ROS pathway NRF2 and its downstream factors, NAD(P)H dehydrogenase (quinone) 1 (NQO1) and heme oxygenase 1 (HO1), and also suppressed the activation of the Wnt signaling pathway p-LRP6, β-catenin, and TCF4 in HCE cells treated with 4-HNE. Meanwhile, SERPINA3K ameliorated the oxidant injury of rat corneas induced by 4-HNE and downregulated ROS systems and the Wnt/β-catenin pathway. CONCLUSIONS. Our findings show that SERPINA3K protected the oxidant damage induced by 4-HNE in the cornea and its underlying mechanism was through suppression of the ROS system and inhibition of the activated Wnt/β-catenin signaling pathway.