title: Glutathione peroxidase 2 and aquaporin 8 as new markers for colonic inflammation in experimental colitis and inflammatory bowel diseases: an important role for H2O2?
abstract: OBJECTIVE
  Different mouse models of inflammatory bowel diseases (IBD) demonstrate various aspects of the pathophysiology of IBD. We looked for overlapping gene expression profiles in three different mouse models of experimental colitis and analysed whether these overlapping genes are of help to find new genes that could be used as general markers in human IBD.
  
  
  METHODS
  Using Agilent mouse TOX oligonucleotide microarrays, we analysed the gene expression profiles in three widely used models of experimental colitis: 2,4,6-trinitrobenzene sulphonic acid, dextran sodium sulfate and CD4CD45RB transfer and looked for overlapping gene expression in these models. Overlapping genes were analysed using Lightcycler (Roche Diagnostics, Mannheim, Germany) in biopsy materials from human IBD and control tissue.
  
  
  RESULTS
  Compared with control mice in dextran sodium sulfate, 2,4,6-trinitrobenzene sulphonic acid and the CD45RB transfer colitis mice five known genes, extracellular proteinase inhibitor (Expi), glutathione peroxidase 2 (Gpx2), mast cell protease 1 (Mcpt1), resistin-like beta (Retnlb) and sulphatase 2 (Sulf2), and two unknown genes were upregulated and the two genes aquaporin 8 (Aqp8) and kallikrein 5 (Klk5) were downregulated in all three models. In human Crohn's disease and ulcerative colitis biopsies, one of the upregulated glutathione peroxidase (Gpx2) and one of the downregulated Aqp8 genes in the mouse models were also differentially expressed in affected colonic tissue of patients with IBD.
  
  
  CONCLUSIONS
  Experimental mouse models are suitable models for the search of new markers for human IBD. As both Gpx2 and Aqp8 are involved in H2O2 metabolism (Gpx2 as a radical scavenger whereas Aqp8 facilitates its diffusion), upregulation of Gpx2 and downregulation of Aqp8 could be a mechanism to defend against severe oxidative stress and indicate that H2O2 is a universal mediator in the inflammatory process in the colon. This provides a focus on homeostasis of the antioxidant pathway and its importance in IBD.
authors.affiliation: Center for Experimental and Molecular Medicine, Academic Medical Center, Amsterdam, The Netherlands. a.a.tevelde@amc.uva.nl
authors.forename: Anje A
authors.initials: AA
authors.lastname: Te Velde
authors.forename: Inge
authors.initials: I
authors.lastname: Pronk
authors.forename: Floor
authors.initials: F
authors.lastname: de Kort
authors.forename: Pieter C F
authors.initials: PC
authors.lastname: Stokkers
mesh_terms: D000328:Adult; D000818:Animals; D020346:Aquaporins / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D003092:Colitis / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism*; D003106:Colon / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D005979:Glutathione Peroxidase / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007082:Ileum / Q000378:metabolism; D015212:Inflammatory Bowel Diseases / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D055815:Young Adult; D000094765:Glutathione Peroxidase GPX1
chemical_list: D020346:Aquaporins; D015415:Biomarkers; C108330:aquaporin 8; D006861:Hydrogen Peroxide; D005979:Glutathione Peroxidase; D000094765:Glutathione Peroxidase GPX1