title: Effects of dominant-negative c-Jun on platelet-derived growth factor-induced vascular smooth muscle cell proliferation.
abstract: Although platelet-derived growth factor (PDGF)-BB is thought to participate in vascular disorders, the mechanism of PDGF-induced vascular smooth muscle cell (SMC) proliferation is not fully understood. This study was undertaken to examine the role of c-Jun in PDGF-BB-induced proliferation of rat aortic SMCs. PDGF-BB (10 ng/mL) significantly increased activator protein (AP)-1 DNA binding activity in SMCs, followed by the increase in [(3)H]thymidine incorporation and cell number. SMCs were infected with recombinant adenovirus containing TAM67, a dominant-negative c-Jun lacking the transactivation domain of wild c-Jun (Ad-DN-c-Jun), to inhibit endogenous AP-1. Ad-DN-c-Jun, which specifically blocked AP-1 transcriptional activity, significantly inhibited PDGF-BB-induced increases in [(3)H]thymidine incorporation or cell number. As shown by flow cytometric analysis, Ad-DN-c-Jun inhibited PDGF-BB-induced entrance of SMCs into S phase, leading to a G(1) arrest. Ad-DN-c-Jun attenuated PDGF-BB-induced downregulation of p27(Kip1), as shown by Western blot analysis, and the prevented PDGF-BB-induced decrease in cyclin E/cyclin-dependent kinase 2 complex-associated p27(Kip1), as shown by immunoprecipitation study. Furthermore, protein kinase assay showed that Ad-DN-c-Jun blocked PDGF-BB-induced activation of cyclin-dependent kinase 2. Our results provide the first evidence that dominant-negative c-Jun inhibits PDGF-BB-induced vascular SMC proliferation by preventing the downregulation of p27(Kip1), thereby supporting the important role of c-Jun in vascular SMC proliferation.
authors.affiliation: Department of Pharmacology, Osaka City University Medical School, Osaka, Japan.
authors.forename: Yumei
authors.initials: Y
authors.lastname: Zhan
authors.forename: Shokei
authors.initials: S
authors.lastname: Kim
authors.forename: Hideo
authors.initials: H
authors.lastname: Yasumoto
authors.forename: Masashi
authors.initials: M
authors.lastname: Namba
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Miyazaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iwao
mesh_terms: D000818:Animals; D000077214:Becaplermin; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division; D016193:G1 Phase; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000378:metabolism; D009154:Mutation; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics / Q000502:physiology*; D020574:Proto-Oncogene Proteins c-sis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017479:Receptors, Platelet-Derived Growth Factor / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D010982:Platelet-Derived Growth Factor; D016755:Proto-Oncogene Proteins c-jun; D020574:Proto-Oncogene Proteins c-sis; D018808:Transcription Factor AP-1; D000077214:Becaplermin; D017479:Receptors, Platelet-Derived Growth Factor