A possible involvement of Nrf2-mediated heme oxygenase-1 up-regulation in protective effect of the proton pump inhibitor pantoprazole against indomethacin-induced gastric damage in rats.
BACKGROUND
Proton pump is an integral membrane protein that is ubiquitous ATP binding cassette (ABC) involved in many transport processes in all living organisms, among which a specialized form of pump, so called p-type proton pump, exists in the parietal cells of stomach. Though proton pump inhibitors (PPIs) are frequently prescribed to prevent nonsteroidal anti-inflammatory drugs (NSAIDs)-induced gastric damage, the acid suppressive actions do not suffice to explain.


METHODS
In order to document the effects of pantoprazole, one of PPIs, on the NSAIDs-induced gastric damage, in vitro and in vivo studies were performed. Immunocytochemistry, Western blot analysis, electrophoretic mobility shift assay and RT-PCR were conducted to evaluate the induction of heme oxygenase-1 (HO-1) through Nrf2 activation in normal gastric mucosal RGM-1 cells or in vivo stomach tissues from rats treated with indomethacin and/or pantoprazole.


RESULTS
Pantoprazole activated Nrf2 through inactivation of Keap1, after which the expression of HO-1 was significantly increased in a dose-dependent manner in RGM-1 cells. Increased ARE-DNA binding activity was observed maximally at 1 h with 300 μM of pantoprazole. The expression of HO-1 induced by pantoprazole was significantly associated with the increased in vitro tube formation (P < 0.05) and angiogenic factors including VEGF, bFGF, and HIF-1α. Indomethacin markedly increased the expressions of TNF-α, IL-1ß, IL-8, NOX-1, ICAM-1 and VCAM, whereas pantoprazole significantly decreased the expressions of indomethacin-induced these inflammatory mediators in accord with pantoprazole-induced HO-1 (P < 0.05) as documented with HO-1 inhibitor. In vivo model of indomethacin-induced gastric damage could validate in vitro-drawn results that pantoprazole remarkably protected against indomethacin-induced gastric damage, in which zinc protoporphyrin (5 mg/kg, ip) significantly abolished the protective efficacy of pantoprazole.


CONCLUSIONS
These results demonstrate that Nrf2-mediated HO-1 induction of PPIs afforded a significant protective effect against NSAIDs-induced gastric damage beyond acid suppressive actions.
Lab of Chemoprevention, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon 406-840, Korea.
Ho-Jae
HJ
Lee
Young-Min
YM
Han
Eun-Hee
EH
Kim
Yoon-Jae
YJ
Kim
Ki-Baik
KB
Hahm
D053799:2-Pyridinylmethylsulfinylbenzimidazoles / Q000494:pharmacology* / Q000627:therapeutic use; D000704:Analysis of Variance; D000818:Animals; D002478:Cells, Cultured; D004790:Enzyme Induction / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D007213:Indomethacin; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D000072019:Kelch-Like ECH-Associated Protein 1; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D000074624:NADPH Oxidase 1; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000187:drug effects; D000077402:Pantoprazole; D054328:Proton Pump Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D011524:Protoporphyrins / Q000494:pharmacology; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D013272:Stomach Diseases / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D004791:Enzyme Inhibitors; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D053583:Interleukin-1beta; D016209:Interleukin-8; D047908:Intracellular Signaling Peptides and Proteins; C486610:KEAP1 protein, rat; D000072019:Kelch-Like ECH-Associated Protein 1; D051267:NF-E2-Related Factor 2; C495637:Nfe2l2 protein, rat; D054328:Proton Pump Inhibitors; D011524:Protoporphyrins; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D042461:Vascular Endothelial Growth Factor A; D016222:Fibroblast Growth Factor 2; D018799:Intercellular Adhesion Molecule-1; C017803:zinc protoporphyrin; D000077402:Pantoprazole; D006419:Heme Oxygenase (Decyclizing); D009247:NADH, NADPH Oxidoreductases; D000074624:NADPH Oxidase 1; D007213:Indomethacin