Oxidative stress enhanced the transforming growth factor-β2-induced epithelial-mesenchymal transition through chemokine ligand 1 on ARPE-19 cell.

Fibroblast-like transformation of retinal pigment epithelial (RPE) cells is a pathological feature of proliferative vitreoretinopathy (PVR) that may cause blindness. The effect of oxidative stress alone or together with transforming growth factor-beta 2 (TGF-β2) on epithelial-mesenchymal transformation (EMT) is not fully understood in RPE. TGF-β2 induced the upregulation EMT markers including α-smooth muscle actin (α-SMA), Snail, and Slug and downregulation of E-cadherin (E-cad) in ARPE-19 cells. Hydrogen peroxide (H ₂ O ₂ ) not only upregulated α-SMA but also enhanced the effect of TGF-β2 on the expression of Snail and Slug. The CXCL family of cytokines could be the mediators of EMT induced by H ₂ O ₂ and TGF-β2. H ₂ O ₂ induced CXCL1, that upregulated α-SMA and fibronectin. Both SB225002, an inhibitor of CXCR2, and antioxidant N-acetylcysteine suppressed the TGF-β2-induced EMT in ARPE-19 cells. Taken together, the results suggest that oxidative stress enhanced TGF-β2-induced EMT through the possible autocrine effect of CXCL1 on CXCR2 in ARPE-19 cells.