Stimulation of corneal epithelial migration by a synthetic peptide (PHSRN) corresponding to the second cell-binding site of fibronectin.
OBJECTIVE
Fibronectin plays an important role in the migration of corneal epithelial cells in vivo. The Arg-Gly-Asp (RGD) sequence in the principal cell binding domain of fibronectin mediates the interaction of fibronectin with integrins, whereas the Pro-His-Ser-Arg-Asn (PHSRN) sequence of fibronectin is thought to modulate this interaction. The authors examined the effects of a PHSRN peptide on corneal epithelial migration in vitro and in vivo.


METHODS
Epithelial migration in vitro was examined with the rabbit cornea in organ culture. The motility and phenotype of simian virus 40-transformed human corneal epithelial (HCE) cells were evaluated by time-lapse and immunofluorescence microscopy, respectively. Tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin was examined by immunoprecipitation and immunoblot analysis. The healing of rabbit corneal epithelial wounds induced by 1-heptanol was evaluated by fluorescein staining.


RESULTS
The PHSRN peptide stimulated corneal epithelial migration in organ culture in a concentration-dependent manner, and it increased HCE cell motility in vitro. The peptide induced the accumulation of F-actin and the formation of focal adhesions at the leading edge of HCE cells. It also upregulated the tyrosine phosphorylation of FAK and paxillin in HCE cells, but it did not affect HCE cell proliferation or attachment to a fibronectin matrix. Administration of the PHSRN peptide in eye drops promoted corneal epithelial wound closure in vivo in a dose-dependent manner. None of these effects of the PHSRN peptide were induced by a control NRSHP peptide.


CONCLUSIONS
The PHSRN peptide mimics many of the effects of fibronectin on corneal epithelial cells and may prove suitable as a substitute for fibronectin in the treatment of persistent corneal epithelial defects.
Kimura
Kazuhiro
K
Department of Ocular Pathophysiology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan. k.kimura@yamaguchi-u.ac.jp
Hattori
Atsushi
A
Usui
Yumiko
Y
Kitazawa
Kayo
K
Naganuma
Masumi
M
Kawamoto
Koji
K
Teranishi
Shinichiro
S
Nomizu
Motoyoshi
M
Nishida
Teruo
T
D000199:Actins / Q000378:metabolism; D000818:Animals; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D002472:Cell Transformation, Viral; D004305:Dose-Response Relationship, Drug; D019573:Epithelium, Corneal / Q000293:injuries / Q000502:physiology*; D005353:Fibronectins / Q000494:pharmacology*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D022001:Focal Adhesions / Q000187:drug effects; D047468:Immunoprecipitation; D008856:Microscopy, Fluorescence; D009924:Organ Culture Techniques; D051419:Paxillin / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology*; D010766:Phosphorylation; D010781:Photography; D011817:Rabbits; D014443:Tyrosine / Q000378:metabolism; D015854:Up-Regulation; D014945:Wound Healing / Q000187:drug effects*
D000199:Actins; D005353:Fibronectins; D051419:Paxillin; D010446:Peptide Fragments; C495978:prolyl-histidyl-seryl-arginyl-asparagine; D014443:Tyrosine; D051416:Focal Adhesion Protein-Tyrosine Kinases