title: Downregulation of matrix metalloproteinase-2 in corneal fibroblasts by interleukin-1 receptor antagonist released from corneal epithelial cells.
abstract: OBJECTIVE
  The authors previously showed that the expression of various junctional proteins in corneal epithelial cells or corneal fibroblasts (CFs) is regulated by the presence of the other cell type in a coculture system. In this study, the effect of corneal epithelial cells on the expression of matrix metalloproteinases (MMPs) in CFs was studied.
  
  
  METHODS
  Human CFs and simian virus 40-transformed human corneal epithelial (HCE) cells were cultured on opposite sides of a collagen vitrigel membrane. Expression of MMPs in CFs was examined by reverse transcription-polymerase chain reaction and immunoblot analyses.
  
  
  RESULTS
  The amounts of MMP-2 mRNA and protein in CFs were decreased by the presence of HCE cells. HCE cells had no effect on the expression of MMP-1 in CFs. HCE cells released interleukin (IL)-1 receptor antagonist (IL-1RA) into the culture medium, and depletion of IL-1RA in HCE cells by RNA interference largely abolished the effect of these cells on MMP-2 expression in CFs. The downregulation of MMP-2 expression in CFs by HCE cells was blocked by an inhibitor of signaling by the mitogen-activated protein kinase (MAPK) ERK (PD98059) but was not affected by those of signaling by the MAPKs p38 (SB203580) or JNK (SP600125).
  
  
  CONCLUSIONS
  Corneal epithelial cells downregulated expression of MMP-2 in CFs in a manner dependent at least in part on the release of IL-1RA from the former cells. This effect might contribute to the attenuation of corneal stromal remodeling by corneal epithelial cells.
authors.affiliation: Department of Ophthalmology, Yamaguchi University Graduate School of Medicine, Ube City, Yamaguchi, Japan. jiae0831@yamaguchi-u.ac.jp
authors.forename: Ji-Ae
authors.initials: JA
authors.lastname: Ko
authors.forename: Ryoji
authors.initials: R
authors.lastname: Yanai
authors.forename: Tai-ichiro
authors.initials: T
authors.lastname: Chikama
authors.forename: Teruo
authors.initials: T
authors.lastname: Nishida
mesh_terms: D002460:Cell Line; D002461:Cell Line, Transformed; D018920:Coculture Techniques; D003315:Cornea / Q000166:cytology / Q000201:enzymology*; D015536:Down-Regulation; D019573:Epithelium, Corneal / Q000166:cytology / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology*; D006801:Humans; D015151:Immunoblotting; D053590:Interleukin 1 Receptor Antagonist Protein / Q000235:genetics / Q000378:metabolism*; D020778:Matrix Metalloproteinase 2 / Q000235:genetics* / Q000378:metabolism*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: D053590:Interleukin 1 Receptor Antagonist Protein; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017472:Receptors, Interleukin-1; D020929:Mitogen-Activated Protein Kinase Kinases; D020778:Matrix Metalloproteinase 2