title: EphA2/Ephrin-A1 signaling complexes restrict corneal epithelial cell migration.
abstract: OBJECTIVE
  Eph/ephrin signaling proteins are present in the corneal epithelium, where their function remains unknown. The authors examined the role of the EphA2 receptor and ephrin-A1 ligand in human corneal epithelial cell migration.
  
  
  METHODS
  Immunohistochemical analysis of EphA2 and ephrin-A1 in healthy and diabetic corneas was performed in concert with linear scratch wound healing studies in primary and telomerase-immortalized human corneal epithelial cells. Corneal epithelial cells were exposed to a soluble ephrin-A1-Fc peptide mimetic that targets EphA2 to trigger receptor phosphorylation and subsequent downregulation. Genetic modulation of EphA2 and ephrin-A1 levels was combined with manipulation of Erk1/2 or Akt signaling during wound healing.
  
  
  RESULTS
  EphA2 was immunolocalized to human corneal epithelial cells in vivo and in vitro. Ephrin-A1 ligand targeting of EphA2 restricted the ability of corneal epithelial cells to seal linear scratch wounds in a manner that was associated with a transient reduction in Erk1/2 and Akt activation state. Ephrin-A1-Fc treatment delayed wound healing independently of Mek-Erk1/2 signaling but was no longer capable of restricting migration after pharmacologic blockade of the PI3K-Akt pathway. Interestingly, ephrin-A1 immunoreactivity was increased in the corneal epithelia of diabetic individuals, mice maintained on a high-fat diet, or cultured corneal epithelial cells exposed to high glucose, which exhibit impaired Akt signaling and slower wound healing responses.
  
  
  CONCLUSIONS
  EphA2 attenuates corneal epithelial cell migration when stimulated by ephrin-A1 ligand in a manner that involves the suppression of Akt. Elevated levels of ephrin-A1 may contribute to diabetic keratopathies by persistently engaging EphA2 and prohibiting Akt-dependent corneal epithelial repair processes.
authors.affiliation: Department of Dermatology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Chicago, IL 60611, USA.
authors.forename: Nihal
authors.initials: N
authors.lastname: Kaplan
authors.forename: Anees
authors.initials: A
authors.lastname: Fatima
authors.forename: Han
authors.initials: H
authors.lastname: Peng
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Bryar
authors.forename: Robert M
authors.initials: RM
authors.lastname: Lavker
authors.forename: Spiro
authors.initials: S
authors.lastname: Getsios
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002465:Cell Movement; D002478:Cells, Cultured; D016510:Corneal Neovascularization / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D004247:DNA / Q000235:genetics*; D003921:Diabetes Mellitus, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D004591:Electrophoresis, Polyacrylamide Gel; D036382:Ephrin-A1 / Q000096:biosynthesis / Q000235:genetics*; D019573:Epithelium, Corneal / Q000378:metabolism* / Q000473:pathology; D005786:Gene Expression Regulation; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D051379:Mice; D008810:Mice, Inbred C57BL; D060888:Real-Time Polymerase Chain Reaction; D036104:Receptor, EphA2 / Q000096:biosynthesis / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics
chemical_list: D036382:Ephrin-A1; D004247:DNA; D036104:Receptor, EphA2