Galectin-7 as a potential mediator of corneal epithelial cell migration

OBJECTIVE: To assess the role of a carbohydrate-binding protein, galectin-7, in reepithelialization of corneal wounds.

METHODS: Transepithelial excimer laser ablations were performed on mouse corneas, and the wounds were allowed to partially heal in vivo for 18 to 22 hours. At the end of the healing period, expression levels of galectin-7 messenger RNA and protein were analyzed using semiquantitative reverse transcriptase-polymerase chain reaction, Western blot analysis, and immunohistochemical localization studies. To determine the effect of exogenous galectin-7 on reepithelialization of corneal wounds, corneas with 2-mm alkali burn wounds were allowed to partially heal in vitro for 20 to 24 hours in serum-free media in the presence or absence of recombinant galectin-7. At the end of the healing period, the wound areas were photographed and quantified.

RESULTS: Expression of galectin-7 messenger RNA and protein was markedly up-regulated in the corneal epithelium after injury. Exogenous galectin-7 stimulated reepithelialization of corneal wounds. The stimulatory effect of galectin-7 on corneal epithelial wound closure was specifically inhibited by a competing sugar, beta-lactose, but not by an irrelevant disaccharide, sucrose.

CONCLUSIONS: Galectin-7 has the potential to mediate corneal epithelial cell migration and reepithelialization of wounds.

CLINICAL RELEVANCE: These findings have broad implications for developing novel, galectin-based, therapeutic strategies for treatment of nonhealing corneal epithelial defects.