Regulation of vascular smooth muscle cell proliferation by nuclear factor-kappaB and its inhibitor, I-kappaB.
Proliferation of vascular smooth muscle cells (SMC) is a crucial event in the formation of atherosclerotic tissues and is regulated by nuclear transcriptional factors including nuclear factor-kappaB (NF-kappaB). We constructed a reporter gene assay to measure NF-kappaB-dependent transcriptional activity in SMC. Thrombin receptor-activating peptide (TRAP) and basic fibroblast growth factor (bFGF) stimulated SMC proliferation and rapidly enhanced the NF-kappaB transcriptional activity in a dose-dependent manner. 4-Cyano-5,5-bis-(methoxyphenyl)4-pentenoic acid (E5510) significantly inhibited SMC proliferation and also suppressed NF-kappaB transcription stimulated by TRAP and bFGF. In contrast, although tumor necrosis factor (TNF)-alpha activated NF-kappaB transcription, E5510 had no effect on TNF-alpha-induced activation. NF-kappaB was activated after the stimulation of TRAP, bFGF, and TNF-alpha in electrophoretic mobility shift assay, and E5510 suppressed the NF-kappaB activation induced by TRAP and bFGF but not the activation by TNF-alpha. Western blot analysis of I-kappaBalpha and I-kappaBbeta, inhibitors of NF-kappaB, indicated that I-kappaBalpha degradation, rather than I-kappaBbeta degradation, was important in NF-kappaB activation after the stimulation of TRAP and bFGF. PD98059, an inhibitor of extracellular signal-regulated kinase (ERK) kinase, suppressed NF-kappaB transcriptional activity and SMC proliferation. The phosphorylation of ERK1/2 was rapidly induced by TRAP and bFGF but not by TNF-alpha. These results indicate that TRAP and bFGF induced I-kappaB degradation and NF-kappaB activation through a distinct pathway from TNF-alpha and that ERK1/2 may play an important role in NF-kappaB activation induced by TRAP and bFGF.
Hoshi
S
S
Eisai Co. Ltd., Tsukuba Research Laboratories, Tokodai 5-1-3, Tsukuba, Ibaraki 300-2635, Japan. m-hoshi@hhc.eisai.co.jp
Goto
M
M
Koyama
N
N
Nomoto
K
K
Tanaka
H
H
D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D020672:I-kappa B Proteins; D007700:Kinetics; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D010766:Phosphorylation; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D051381:Rats; D014158:Transcription, Genetic / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D004268:DNA-Binding Proteins; D005229:Fatty Acids, Monounsaturated; D005419:Flavonoids; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606206:Nfkbia protein, rat; D010446:Peptide Fragments; D010975:Platelet Aggregation Inhibitors; D014409:Tumor Necrosis Factor-alpha; C082835:thrombin receptor peptide (42-47); D016222:Fibroblast Growth Factor 2; D000072000:NF-KappaB Inhibitor alpha; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; C054678:Satigrel