title: Expression of 1-cys peroxiredoxin in the corneal wound-healing process.
abstract: OBJECTIVE
  To study the regulation by mitomycin C (MMC) of 1-cys peroxiredoxin (Prx) expression during the corneal wound-healing process and its induction pathway in cultured bovine keratocytes (BKs).
  
  
  METHODS
  Rat corneas were excised at 4 hours, 12 hours, 1 day, 3 days, and 7 days after photorefractive keratectomy (PRK). Expression of 1-cys Prx in the corneas was examined by Northern blot and immunoblot analyses. Cultured BKs were exposed to 0.02% MMC for 5 minutes and maintained under normal culture conditions for different time periods. Subsequently, levels of 1-cys Prx and extracellular signal-regulated kinase (ERK)1/2 expression were measured by immunoblot analysis using polyclonal 1-cys Prx, ERK1/2, or phospho-ERK1/2 antibodies. To inhibit ERK1/2 activation, the BKs were pretreated with 50 micromol/mL PD98059 for 1 hour before MMC exposure and incubated in complete medium with or without PD98059 for 24 hours. MMC-induced cytotoxicity was determined by colorimetric cell-counting kit-8 assay.
  
  
  RESULTS
  Increased levels of 1-cys Prx expression were seen in wounded rat corneas at 12 hours after injury and reached the highest level between 1 and 3 days, during which time active proliferation occurred. Induction of 1-cys Prx expression was obvious in proliferating BKs stimulated by growth factors. MMC treatment in cultured BKs resulted in increased expression of 1-cys Prx and phospho-ERK1/2 in a time-dependent manner. Treatment with 50 micromol/mL PD98059 significantly inhibited the active ERK1/2 and 1-cys Prx expression induced by MMC, leading to synergistic cytotoxicity in the BKs.
  
  
  CONCLUSIONS
  1-Cys Prx may function as an important enzyme in cell proliferation during the postinjury corneal wound-healing process. Furthermore, the induction of 1-cys Prx expression through the ERK1/2 signaling pathway may contribute to cellular defense against cytotoxic agents, thus playing an important role in cell survival.
authors.affiliation: Department of Ophthalmology and Asan Institute for Life Sciences, University of Ulsan College of Medicine, Asan Medical Center, 388-1 Pungnap-2 dong, Songpa-gu, Seoul 137-756, Korea.
authors.forename: Jhang Ho
authors.initials: JH
authors.lastname: Pak
authors.forename: Hyun-jeung
authors.initials: HJ
authors.lastname: Choi
authors.forename: Chul Young
authors.initials: CY
authors.lastname: Choi
authors.forename: Hungwon
authors.initials: H
authors.lastname: Tchah
mesh_terms: D000477:Alkylating Agents / Q000494:pharmacology; D000818:Animals; D002417:Cattle; D018929:Cell Culture Techniques; D002470:Cell Survival; D003315:Cornea / Q000601:surgery; D003319:Corneal Stroma / Q000166:cytology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D015151:Immunoblotting; D054018:Lasers, Excimer; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D016685:Mitomycin / Q000494:pharmacology; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism*; D054464:Peroxiredoxins; D010766:Phosphorylation; D018903:Photorefractive Keratectomy; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014945:Wound Healing / Q000502:physiology*
chemical_list: D000477:Alkylating Agents; D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D016685:Mitomycin; D010544:Peroxidases; D054464:Peroxiredoxins; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3