Oxidized EPA activates PPARα-dependent transcription in BAECs.

PPARγ (A) or PPARα (B) activation was studied in BAECs using a yeast 2-hybrid Gal4 transfection assay for ligand-dependent activation. Cells were transfected with PPARα-LBD or PPARγ-LBD fused to the yeast transcription factor Gal4, or a control Gal4 plasmid. All cells were transfected with a yeast Gal4-binding site luciferase reporter construct. Activation events at the LBD were measured by increased luciferase activity. Gal4 alone is not activated in mammalian cells. Cells were treated with native EPA (EPA), oxidized EPA (oxEPA), or synthetic agonists of PPARα (fen acid: fenofibric acid, 100 μM) or PPARγ (roz: rosiglitazone, 1 μM). (A) Oxidized EPA led to a modest induction of PPARγ activation that was not dose dependent and was comparable to that observed with native EPA. (B) Dose-response curves for PPARα activation by native EPA (closed square) or oxidized EPA (closed diamond) are shown. Native and oxidized EPA treatment of cells transfected with the control Gal4 construct (open symbols) revealed no luciferase activity. Insert shows PPARα activation by fenofibric acid (fen acid; 100 μM), but not by vehicle (Veh) alone.