Galectin‐3 Promotes Formation of Lamellipodia in Corneal Epithelial Cells by Interacting with α3β1 Integrins

Abstract

Recent studies in our laboratory have shown that galectin‐3, a β‐galactoside binding lectin, mediates re‐epithelialization of corneal wounds. In an effort to characterize the molecular mechanism by which galectin‐3 stimulates the cell migration, the goals of the present study are to: (i) characterize the lectin‐induced migratory phenotypes and Rac1 activation in corneal epithelial cells in vitro, and (ii) determine whether carbohydrate‐based interactions between galectin‐3 and integrins play a role in the lectin‐induced lamellipodia formation in corneal epithelium. Specifically, exogenous galectin‐3 but not galectin‐1, and ‐8 induced formation of lamellipodia in human corneal epithelial cells in a β‐lactose‐inhibitable manner and increased Rac1 activity. α3β1, α6β1, α6β4 and & αv‐integrins and laminin‐5 were identified as major galectin‐3‐binding proteins in corneal epithelial cells by affinity chromatography of corneal epithelial cell lysates on a galectin‐3‐Sepharose column, followed by MALDI‐TOF MS analysis. Furthermore, preincubation of cells with anti‐α3 integrin function‐blocking antibody (P1B5) significantly inhibited the galectin‐3‐induced lamellipodia. These data suggest that galectin‐3 may influence re‐epithelialization of corneal wounds by initiating the formation of lamellipodia, at least in part, through its interaction with α3β1 integrins.