Sequence specificity of the PHSRN peptide from fibronectin on corneal epithelial migration.

The Pro-His-Ser-Arg-Asn (PHSRN) sequence in fibronectin is a second cell-binding site that synergistically affects with Arg-Gly-Asp. The PHSRN peptide also induces cell invasion and accelerates wound healing. Here, we examined the sequence specificity of PHSRN on corneal epithelial migration using various synthetic peptides. Elongation and deletion analyses of Ac-PHSRN-NH(2) suggest that the five amino acid length was a minimum and essential sequence for promotion of rabbit corneal epithelial migration ex vivo. Additionally, alanine substituted analysis indicated that the Ser- and Arg-residues are critical for the biological activities. The Ser-Arg motif is involved in various biologically active peptides, suggesting that the unique sequence interacts with cellular receptor(s) and regulates biological functions. Further, the N-acetyl and C-amide of Ac-PHSRN-NH(2) contributed effectively for the chemical stability in tears. The Ac-PHSRN-NH(2) peptide has potential to use as a therapeutic reagent especially for corneal wound healing.