Stable reporter cell lines for peroxisome proliferator-activated receptor y (PPARy)-mediated modulation of gene expression

Activation of peroxisome proliferator-activated receptor ¿ (PPAR¿) by ligands is associated with beneficial health effects, including anti-inflammatory and insulin-sensitizing effects. The aim of the current study was to develop luciferase reporter gene assays to enable fast and low-cost measurement of PPAR¿ agonist and antagonist activity. Two reporter gene assays, PPAR¿1 CALUX and PPAR¿2 CALUX, were developed by stable transfection of U2OS cells with an expression vector for PPAR¿1 or PPAR¿2 and a pGL3–3xPPRE–tata-luc or pGL4–3xPPRE–tata-luc reporter construct, respectively. PPAR¿1 CALUX and PPAR¿2 CALUX cells showed similar concentration-dependent luciferase induction upon exposure to the PPAR¿ agonists rosiglitazone, troglitazone, pioglitazone, ciglitazone, netoglitazone, and 15-deoxy-¿12,14-prostaglandin J2. The potency to induce luciferase decreased in the following order: rosiglitazone > troglitazone = pioglitazone > netoglitazone > ciglitazone. A concentration-dependent decrease in the response to 50 nM rosiglitazone was observed on the addition of PPAR¿ antagonist GW9662 or T0070907 in both PPAR¿1 CALUX and PPAR¿2 CALUX cells. The PPARa agonists WY14643 and fenofibrate failed to induce luciferase activity, confirming the specificity of these cell lines for PPAR¿ agonists. In conclusion, PPAR¿1 CALUX and PPAR¿2 CALUX cells provide a reliable and useful tool to screen (bio)chemicals for PPAR¿ agonist or antagonist activity.