title: Insulin growth factor promotes human corneal fibroblast network formation in vitro.
abstract: OBJECTIVE
  Corneal fibroblast cell (CFC) reticulation is involved in the structural development of corneal stroma and in wound healing. In an earlier paper, it was reported that the expression of VEGFR-1 by CFCs is related to their reticulogenic properties in vitro and decreases with the age of the donors. The present study was focused on the nonreticulogenic corneal fibroblast population and explored whether these cells can be induced to form cell networks in vitro.
  
  
  METHODS
  The network formation was analyzed using an array of signaling pathway inhibitors: wortmannin for PI3 kinase, U0126 for MEK-1/2 kinase, Rottlerin for PKC, farnesyl transferase inhibitor (FTI-277) for Ras, and picropodophyllin (PPP) for IGFR-1. Among the several growth factors studied, IGF seemed to be crucial to cell network formation. The presence of IGF signaling was demonstrated using gene array analysis and was confirmed by RT-PCR and immunocytochemistry and by cell network formation on reduced synthetic basement membrane arrays. The pleiotropic effect of IGF-1 on the cells was analyzed by protein cytokine array.
  
  
  RESULTS
  The genesis of reticulation was found to occur via MEK-1/2 and IGFR pathways, since inhibitors of these signaling pathways reduced or prevented cell network formation. The addition of exogenous IGF-1 generated a cell network structure in corneal fibroblasts obtained from healthy donors, indicating the involvement of IGF-1.
  
  
  CONCLUSIONS
  IGF signaling and the MEK-1/2 pathway are involved in the cell network formation of corneal fibroblast cells from aged donors.
authors.affiliation: INSERM (Institut National de la Santé et de la Recherche Médicale) UMRS (Unité Mixte de Recherche Scientifique) 872, Faculté de Médecine Paris VI, Paris, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Berthaut
authors.forename: Pezhman
authors.initials: P
authors.lastname: Mirshahi
authors.forename: Nadia
authors.initials: N
authors.lastname: Benabbou
authors.forename: Elodie
authors.initials: E
authors.lastname: Ducros
authors.forename: Aureliou
authors.initials: A
authors.lastname: Agra
authors.forename: Amu
authors.initials: A
authors.lastname: Therwath
authors.forename: Jean Marc
authors.initials: JM
authors.lastname: Legeais
authors.forename: Massoud
authors.initials: M
authors.lastname: Mirshahi
mesh_terms: D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D060527:Corneal Keratocytes / Q000166:cytology* / Q000378:metabolism; D003319:Corneal Stroma / Q000166:cytology* / Q000378:metabolism; D016207:Cytokines / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D048369:MAP Kinase Kinase 1 / Q000378:metabolism; D048370:MAP Kinase Kinase 2 / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014945:Wound Healing / Q000502:physiology
chemical_list: D016207:Cytokines; D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; C482128:MAP2K2 protein, human; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; C482125:MAP2K1 protein, human