Upregulation of Heme Oxygenase-1 as a Host Mechanism for Protection Against Nitric Oxide–induced Damage in Human Renal Epithelial Cells - 22/08/11
Résumé |
Objectives |
To examine whether urinary tract infection–associated stimuli could regulate heme oxygenase-1 (HO-1) expression and to asses the significance of HO-1 in protecting urinary tract epithelial cells against nitric oxide (NO)-induced damage.
Methods |
Heme oxygenase-1 expression was investigated in the human renal epithelial cell line A498 in response to the uropathogenic Escherichia coli (UPEC) strain IA2, the NO-donor DETA/NONOate (DETA/NO), and proinflammatory cytokines (interleukin-1β, tumor necrosis factor-⍺, and interferon-γ) using reverse transcriptase polymerase chain reaction and Western blot analysis. Cell viability was examined by the trypan blue exclusion test and light microscopy.
Results |
The HO-1 inducer hemin and DETA/NO increased HO-1 expression in A498 cells, and glutathione depletion further increased HO-1 expression in response to DETA/NO and hemin. Stimulation with a UPEC strain or cytokines did not upregulate HO-1 expression. The cytokines induced inducible NO synthase expression and caused an increase in nitrite production. Hemin significantly decreased cytokine-induced NO production (P <0.001). DETA/NO decreased the cell viability by approximately 75%, but hemin was able to attenuate DETA/NO-induced cell damage.
Conclusions |
The expression of HO-1 increased in human renal epithelial cells in response to NO, and the expression was further enhanced in glutathione-depleted cells. The bacteria per se or proinflammatory cytokines were not able to upregulate HO-1. Heme oxygenase-1 protects the cells against NO by feedback inhibition of NO production and by decreasing cell damage.
Le texte complet de cet article est disponible en PDF.Plan
This project was supported by the Swedish Medical Research Council (12601) and the Faculty of Natural Sciences at the University of Kalmar. |
Vol 73 - N° 5
P. 1150-1155 - mai 2009 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
L’accès au texte intégral de cet article nécessite un abonnement.
Déjà abonné à cette revue ?