title: Nitric oxide induces HIF-1α stabilization and expression of intestinal trefoil factor in the damaged rat jejunum and modulates ulcer healing.
abstract: BACKGROUND
  The induction of intestinal trefoil factor (ITF) has been reported to depend on hypoxia-inducible factor-1 (HIF-1). Nitric oxide modulates HIF-1 activity. The present study aims to analyze the role of nitric oxide in jejunum damage induced by indomethacin and its ability to modulate epithelial function through the expression of ITF.
  
  
  METHODS
  Rats received indomethacin (7.5 mg/kg, s.c., twice), and a time course analysis of damage was performed (24-96 h after the first administration). In these animals, the role of nitric oxide was analyzed by using 1400W, a selective iNOS activity inhibitor (5 mg/kg, i.p./day), on: (1) intestinal damage, (2) ulcer healing, (3) the presence of nitrated proteins in the jejunum and (4) the protein expression of inducible nitric oxide synthase (iNOS), HIF-1α and ITF.
  
  
  RESULTS
  Indomethacin induced damage in the jejunum that was apparent at 24 h and peaked at 48-72 h. An increase in iNOS, HIF-1α, ITF and nitrated proteins was observed in the injured jejunum. Immunoprecipitation of HIF-1α allowed determination of the nitration/nitrosylation of this protein by using nitrotyrosine and nitrocysteine antibodies. Blockade of iNOS activity did not significantly modify damage or iNOS expression, but did significantly impede ITF induction, HIF-1α stabilization and HIF-1α detection with antibodies against nitrated proteins. In parallel to these results, pre-treatment with 1400W delayed the healing of the ulcer provoked by indomethacin.
  
  
  CONCLUSIONS
  These results suggest that iNOS-derived NO is involved in HIF-1α stabilization, probably through S-nitrosylation, and ITF expression in goblet cells of the damaged jejunum of indomethacin-treated rats and mediates ulcer healing.
authors.affiliation: Department of Pharmacology and CIBERehd, Faculty of Medicine, University of Valencia, Avda. Blasco Ibanez 15-17, 46010 Valencia, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Riaño
authors.forename: D
authors.initials: D
authors.lastname: Ortiz-Masià
authors.forename: M
authors.initials: M
authors.lastname: Velázquez
authors.forename: S
authors.initials: S
authors.lastname: Calatayud
authors.forename: J V
authors.initials: JV
authors.lastname: Esplugues
authors.forename: Maria Dolores
authors.initials: MD
authors.lastname: Barrachina
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000633:toxicity; D020397:Goblet Cells / Q000378:metabolism; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D007097:Imines / Q000494:pharmacology; D047468:Immunoprecipitation; D007213:Indomethacin / Q000633:toxicity*; D007413:Intestinal Mucosa / Q000378:metabolism; D007583:Jejunum / Q000187:drug effects / Q000473:pathology; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010437:Peptic Ulcer / Q000139:chemically induced / Q000473:pathology; D010455:Peptides / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D000071164:Trefoil Factor-2
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007097:Imines; C496401:N-((3-(aminomethyl)phenyl)methyl)ethanimidamide; D010455:Peptides; D000071164:Trefoil Factor-2; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D007213:Indomethacin