Effects of white light on beta-catenin signaling pathway in retinal pigment epithelium

This study investigated the effect of visible light exposure on retinal pigment epithelium (RPE). The activation of Wnt/beta-catenin pathway was investigated by immunofluorescence and Western blot analysis using human retinal pigment epithelial (ARPE-19) cells, which demonstrated that the exposure of white light induced the activation of the Wnt/beta-catenin pathway. Real time RT-PCR demonstrated that the mRNA of alpha-smooth muscle actin (alpha-SMA), and vimentin increased 2.5-4-fold and that of zona occludens 1 (ZO-1) decreased approximately 0.8-fold after white light exposure. The up-regulation of vimentin expression and the down-regulation of ZO-1 were evident by Western blot analysis and immunohistochemistry. Moreover, the ability of phagocytosis of ARPE-19 cells decreased 0.6-fold after light exposure. Together, white light exposure was supposed to induce the activation of Wnt/beta-catenin pathway, the changes in the expression markers of epithelial and mesenchymal cells in RPE cells, and the concomitant impairment of the ability of phagocytosis.