A peptide from fibronectin cell-binding domain inhibits attachment of epithelial cells

Fibronectin is thought to contribute to the adhesion of corneal epithelium during epithelial repair, presumably by mediating epithelial attachment to stroma during epithelial migration. To understand the mechanism of the interaction of fibronectin with corneal epithelial cells, the effects of intact plasma fibronectin and of the synthetic peptide GRGDS from the cell binding domain of fibronectin on the attachment of rabbit corneal epithelial cells have been examined. When dissociated epithelial cells were plated on fibronectin-coated culture dishes, the number of cells that attached increased in proportion to the concentration of fibronectin used for coating. Attachment of the cells was inhibited in a dose-dependent manner by the addition of GRGDS to the medium. When the structurally similar control peptide GRGES was added to the medium, no inhibition of epithelial attachment was observed. Our results demonstrate that corneal epithelial cells use an adhesive recognition system for fibronectin related to that characterized in fibroblastic cells. GRGDS thus presumably competes for receptors for fibronectin on epithelial cells of the cornea, resulting in the observed inhibition of attachment. These results identify a mechanism for corneal epithelial cell adhesion, compatible with that identified in other fibronectin-dependent systems.