Involvement of NF‐κB in the regulation of cyclooxygenase‐2 protein expression in LPS‐stimulated J774 macrophages

Abstract

We investigated the involvement of NF-κB in the regulation of COX-2 protein expression and prostaglandin production in LPS-stimulated J774 macrophages. Incubation of J774 cells with LPS (1 μg/ml) for 24 h caused an increase of COX-2 protein expression and accumulation of both PGE 2 and 6-keto-PGF 1α in the cell culture medium. Ammonium pyrrolidinedithiocarbamate (APDC, 0.1, 1, 10 μM) and N -α- p -tosyl- l -lysine chloromethylketone (TLCK, 1, 10, 100 μM), two inhibitors of NF-κB activation, suppressed in a concentration-dependent manner both LPS-induced COX-2 protein expression and prostanoid generation. Moreover, APDC and TLCK both inhibited the LPS-induced increase of NF-κB DNA binding activity and prevented IκB-α degradation. Our results show for the first time that NF-κB is involved in COX-2 protein expression in LPS-stimulated J774 macrophages and suggest that inhibitors of NF-κB activation may represent a useful tool for the pharmacological control of inflammation.