title: Regulation of membrane-associated mucins in the human corneal epithelial cells by dexamethasone.
abstract: OBJECTIVE
  To study the influence of dexamethasone on membrane-associated mucins produced by human corneal epithelial cells.
  
  
  METHODS
  Human corneal epithelial cells were cultured in medium supplemented with various concentrations of dexamethasone (ranging from 10 to 10 M). Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis using monoclonal antibodies specific for human MUC1 (HMFG-1), MUC4 (1G8), and MUC16 (OC125) were performed to evaluate the effect of dexamethasone on membrane-associated mucin expression. The effect of glucocorticoid receptor antagonist (RU38486) on dexamethasone-induced mucin expression was estimated.
  
  
  RESULTS
  RT-PCR revealed that MUC1 and MUC16 gene expression were upregulated 48 hours after addition of dexamethasone and that MUC4 gene expression was downregulated in the same condition. Western blot analysis showed that MUC1 and MUC16 proteins were increased after addition of dexamethasone. However, MUC4 was not detected by anti-MUC4 monoclonal antibody (1G8) for ASGP-2 under our conditions. Treatment with RU38486 inhibited the changes of MUC1, MUC4, and MUC16 by dexamethasone; thus, the effect of dexamethasone on mucin expression is mediated by glucocorticoid receptors.
  
  
  CONCLUSIONS
  This study shows that MUC1, MUC4, and MUC16 are regulated differently by dexamethasone in human corneal epithelial cells. External application of dexamethasone might affect the precorneal mucin.
authors.affiliation: Department of Ophthalmology, Institute of Vision Research, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kyoung Yul
authors.initials: KY
authors.lastname: Seo
authors.forename: So-Hyang
authors.initials: SH
authors.lastname: Chung
authors.forename: Joon H
authors.initials: JH
authors.lastname: Lee
authors.forename: Mi Young
authors.initials: MY
authors.lastname: Park
authors.forename: Eung Kweon
authors.initials: EK
authors.lastname: Kim
mesh_terms: D000951:Antigens, Neoplasm / Q000235:genetics*; D015153:Blotting, Western; D018394:CA-125 Antigen / Q000235:genetics*; D002460:Cell Line; D003907:Dexamethasone / Q000494:pharmacology*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D019573:Epithelium, Corneal / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D005938:Glucocorticoids / Q000494:pharmacology*; D006727:Hormone Antagonists / Q000494:pharmacology; D006801:Humans; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D015735:Mifepristone / Q000494:pharmacology; D018396:Mucin-1; D055264:Mucin-4; D009077:Mucins / Q000037:antagonists & inhibitors / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000951:Antigens, Neoplasm; D018394:CA-125 Antigen; D005938:Glucocorticoids; D006727:Hormone Antagonists; C060192:MUC1 protein, human; C451759:MUC16 protein, human; C524658:MUC4 protein, human; D008565:Membrane Proteins; D018396:Mucin-1; D055264:Mucin-4; D009077:Mucins; D015735:Mifepristone; D003907:Dexamethasone