FIGURE 6.

Peroxidized PUFAs promote PPARγ-mediated transcription and binding of PPARγ to β-catenin and suppress β-catenin/TCF-mediated transcription. A, luciferase activity in C2C12 cells transfected with a PPARE-luc reporter construct and treated with vehicle (3.3% BSA in PBS), RGL (5 μm), or the indicated peroxidized PUFAs (3, 10, 30, 60, 100 μm) for 24 h. Bars represent the mean ± S.D. of triplicate determinations. *, p < 0.05 versus vehicle by ANOVA. B, C2C12 cells were incubated with vehicle or the indicated peroxidized PUFAs (10 μm) for 1 h. Cell lysates were immunoprecipitated (IP) with protein A-Sepharose in combination with the non-immune IgG or an anti-PPARγ2 antibody. Immunoprecipitates were analyzed by Western blotting (WB) using anti-β-catenin or anti-PPARγ2 antibodies. C, β-catenin protein levels by Western blotting of OB-6γ2 cell extracts. Cells were cultured as described under “Experimental Procedures” to induce or repress PPARγ2 gene expression and then incubated with vehicle, 9-HODE (10 μm), or RGL (5 μm) for 4 h. D, luciferase activity in C2C12 cells transfected with a TCF-luc reporter construct and co-transfected with either an empty vector (pcDNA) or a PPARγ2 expression construct followed by treatment with vehicle (PBS) or Wnt3a for 24 h. Bars represent the mean ± S.D. of triplicate determinations. *, p < 0.05 versus respective empty vector control.