PLATELET-DERIVED GROWTH FACTOR-STIMULATED SUPEROXIDE ANION PRODUCTIONMODULATES ACTIVATION OF TRANSCRIPTION FACTOR NF-KAPPA-B AND EXPRESSION OF MONOCYTE CHEMOATTRACTANT PROTEIN-1 IN HUMAN AORTIC SMOOTH-MUSCLE CELLS

Background Platelet-derived growth factor (PDGF) and superoxide anion (O-2(.-)) have been implicated in vascular diseases. We investigated w hether PDGF stimulates the production of O-2(.-) in human aortic smoot h muscle cells (HSMCs) and whether O-2(.-) leads in this way to the ac tivation of nuclear factor-kappa B (NF-kappa B) and induction of monoc yte chemoattractant protein 1 (MCP-1) in PDGF-stimulated HSMCs. Method s and Results PDGF-AB concentration-and time-dependently stimulated O- 2(.-) generation from HSMCs. The stimulatory effect of PDGF-AB was mim icked by PDGF-BB but not by PDGF-PLA. The generation of O-2(.-) by PDG F-AB was attenuated by the NAD(P)H oxidase inhibitor iodonium diphenyl , the spe cific protein kinase C (PKC) inhibitor Ro 31-8220, and the p hosphatidylinositol 3-kinase inhibitor wortmannin. Allopurinol and nif edipine had no effect on PDGF-AB-induced O-2(.-) release, whereas indo methacin potentiated this response. Gel mobility shift assay revealed that PDGF-AB increased the binding activity of NF-kappa B, which conta ined predominantly the p50/p65 heterodimer in nuclear extracts from HS MCs. Superoxide dismutase as well as iodonium diphenyl, Ro 31-8220, an d wortmannin attenuated PDGF-AB-induced activation of NF-kappa B and e xpression of MCP-1 mRNA. In contrast, superoxide dismutase did not inh ibit the interleukin-1 beta-induced NF-kappa B activation. Conclusions The results demonstrate that PDGF stimulates O-2(.-) generation in HS MCs via PKC-dependent and wortmannin-sensitive pathways involving flav oenzyme(s). This PDGF-induced O-2(.-) production may be involved in va scular lesion formation by mediating, at least in part, NF-kappa B act ivation and MCP-1 induction.