title: Expression of Delta Np63 in response to phorbol ester in human limbal epithelial cells expanded on intact human amniotic membrane.
abstract: OBJECTIVE
  To evaluate the effect of phorbol 12-myristate 13-acetate (PMA) on the expression of Delta Np63 in human limbal epithelial cells (HLECs) during ex vivo expansion on amniotic membrane (AM).
  
  
  METHODS
  Primary HLECs were cultured either on AM or plastic surfaces and were treated with 1 micro g/mL PMA for 24 hours. Expression of Delta Np63 and the differentiation-associated gap junctional protein connexin 43 (Cx43) were studied by laser scanning microscopy.
  
  
  RESULTS
  The labeling index (LI) of Delta Np63 was higher in HLECs cultured on AM than in HLECs grown on plastic (81.4% +/- 12.2% and 66.6% +/- 16.5%, respectively; P < 0.001). After PMA treatment, Delta Np63 expression in HLECs on plastic dramatically decreased to 20.4% +/- 11.4%. However, HLECs cultured on AM showed only a moderate decrease in Delta Np63 expression (56.4% +/- 10.9%, P < 0.001) after PMA treatment. It was also observed that 72.8% +/- 17.5% of the Delta Np63-positive cells in untreated HLECs cultured on plastic coexpressed Cx43, in contrast to only 21.9% +/- 3.7% of the Delta Np63-positive cells in HLECs cultured on AM (P < 0.001). The latter indicates that growth over AM preserves limbal phenotype, whereas growth over plastic surface induces or allows transition toward corneal peripheral phenotype.
  
  
  CONCLUSIONS
  Delta Np63 protein is typically detected in human corneal epithelial cells with high proliferative capacity including, limbal epithelial stem cells (SCs) and probably also transient amplifying cells (TACs). AM supports Delta Np63 protein expression in HLECs and maintains a higher resistance against phorbol ester-induced differentiation, indicating that characteristic signs of limbal epithelial progenitor cells may be preserved during ex vivo expansion on AM.
authors.affiliation: Department of Ophthalmology, University of Essen, Essen, Germany.
authors.forename: Elias E
authors.initials: EE
authors.lastname: Hernandez Galindo
authors.forename: Carsten
authors.initials: C
authors.lastname: Theiss
authors.forename: Klaus-P
authors.initials: KP
authors.lastname: Steuhl
authors.forename: Daniel
authors.initials: D
authors.lastname: Meller
mesh_terms: D000328:Adult; D000650:Amnion; D002273:Carcinogens / Q000494:pharmacology*; D002478:Cells, Cultured; D018031:Connexin 43 / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D019573:Epithelium, Corneal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D016850:Limbus Corneae / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D018613:Microscopy, Confocal; D008875:Middle Aged; D013234:Stem Cells / Q000166:cytology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
chemical_list: D002273:Carcinogens; D018031:Connexin 43; D004268:DNA-Binding Proteins; C077214:L1Hs-encoded protein p40, human; D013755:Tetradecanoylphorbol Acetate