Molecular mechanisms of dexamethasone inhibition of nitric oxide synthase expression in interleukin 1β-stimulated mesangial cells: Evidence for the involvement of transcriptional and posttranscriptional regulation

摘要

Inducible nitric oxide synthase (iNOS; EC 1.14.13.39) is expressed in rat glomerular mesangial cells upon exposure to the inflammatory cytokine interleukin 1β (IL-1β). We have reported that nanomolar concentrations of dexamethasone suppress IL-1β-induced iNOS protein expres- sion and production of nitrite, the stable end product of NO formation, without affecting IL-1β-triggered increase in iNOS mRNA levels. We now have studied the mechanisms by which dexamethasone suppresses IL-1β-stimulated iNOS expres- sion in mesangial cells.