Advanced glycosylation end products induce NF-kappaB dependent iNOS expression in RAW 264.7 cells

Advanced glycosylation end products (AGEs) have been implicated in the pathogenesis of diabetic complications. Treatment of RAW 264.7 macrophages with bovine serum albumin (BSA)-derived AGEs caused dose- and time-dependent increases in nitrite production and inducible nitric oxide synthase (iNOS) expression. These effects were blocked by the nuclear factor-kappa B (NF-kappaB) inhibitor, pyrrolidone dithiocarbamate (PDTC). BSA-AGEs also stimulated the translocation of p65 NF-kappaB from cytosol to the nucleus. Electrophoretic mobility shift assay revealed that the NF-kappaB DNA-protein-binding activity was enhanced by AGEs. The tyrosine kinase inhibitor, genistein, the phosphatidylinositol-3-kinase (PI 3-K) inhibitor, LY 294002, the protein kinase C (PKC) inhibitor, Ro 31-8220, and the p38 mitogen-activated protein kinase (MAPK) inhibitor, SB 203580, all inhibited AGEs-stimulated iNOS expression, NO release, NF-kappaB translocation and NF-kappaB DNA binding activity. These results suggest that AGEs may activate NF-kappaB via an upstream signaling cascade composed of tyrosine kinase, PI 3-K, PKC, and p38 MAPK, resulting in the induction of iNOS expression in RAW 264.7 macrophages.