Gliadin increases iNOS gene expression in interferon-gamma-stimulated RAW 264.7 cells through a mechanism involving NF-kappa B.

Nitric oxide (NO) plays an important role in the pathogenesis of the histological changes seen in coeliac disease. We have investigated the effect of peptic-tryptic digest of gliadin (Pt-G) and gliadin (G) on inducible nitric oxide synthase (iNOS) protein expression in RAW 264.7 macrophages stimulated with interferon-gamma (IFN-gamma). Pt-G and G enhanced in a concentration and time-dependent manner NO production by IFN-gamma-stimulated RAW 264.7 cells. The increase of iNOS protein expression was correlated with NF-kappaB/DNA binding activity and occurred at transcriptional level. Our results show that the effect of Pt-G and G on enhancement of iNOS protein expression in IFN-gamma-treated RAW 264.7 cells is mainly mediated through NF-kappaB and suggest that blockage of NF-kappaB activation reduces enhancing effect of gluten on NO production in inflamed mucosa of coeliac patients.