FIGURE 8.

PGC-1β inhibits PDGF-induced AP-1 transcriptional activity. A, serial deletion constructs of the rat MCM4 promoter were transfected into VSMCs. After 12 h, cells were infected with AdPGC-1β or AdGFP and stimulated with PDGF-BB for an additional 24 h. Luciferase activity was measured with the dual luciferase reporter assay system. Cotransfected thymidine kinase-driven Renilla luciferase served as the internal control. The numbers indicate the distance in nucleotides from the transcription start site (+1) of the rat MCM4 gene. B, VSMCs were transfected with the MCM4 promoter (-377/+161) or MCM4 (-377/+161) mut-luciferase constructs, and luciferase activity was measured as above. C, VSMCs were transiently transfected with AP-1-Luc and infected with AdGFP or AdPGC-1β. Cells were stimulated with PDGF-BB (10 ng/ml) for 24 h, and luciferase activity was measured as above. D, VSMCs were infected with AdGFP or AdPGC-1β and treated with 10 ng/ml PDGF-BB for 8 h. ChIP assays were performed using antibodies against c-Jun and normal rabbit IgG. Data shown are from three independent experiments. E, Coimmunoprecipitation was performed with an antibody against PGC-1β in VSMCs. Normal rabbit IgG served as a negative control. Input samples were loaded as 10% of total cell extracts. Blots were probed with antibodies as indicated in each panel. IP, immunoprecipitation. F, coimmunoprecipitation was performed with an antibody against c-Jun in VSMCs treated with AdGFP or AdPGC-1β. Normal rabbit IgG served as a negative control. Input samples were loaded as 10% of total cell extracts used for the coimmunoprecipitation. Blots were probed with antibodies as indicated in each panel. *, p < 0.05; **, p < 0.01.