Two Synthetic Ligands for Peroxisome Proliferator- Activated Receptor $\gamma$

The peroxisome proliferator-activated receptor $\gamma$ (PPAR${\gamma}$) is the molecular target for a class of drugs, the antidiabetic thiazolidnediones (TZDs). The heterodimer of PPAR${\gamma}$ with retinoid X receptor (RXR) plays a central role in the regulation of adipogenesis and insulin sensitization. We synthesized two chemicals, DANA87 and DANA88, sharing structural characteristics with TZDs. Given this structural similarity, it was hypothesized that DANA87 and DANA88 may act as PPAR$\gamma$ ligands. In transient transfection assays, DANA87 and DANA88 caused slight increases in the endogenous expression of a luciferase reporter gene containing the PPAR responsive element in 3T3-L1 preadipocytes. However, DANA87 and DANA88 significantly inhibited troglitazone-induced reporter gene activation when cells were treated with a combination of DANA87 or DANA 88 and troglitazone, one of the TZDs that activate PPAR$\gamma$. These results suggest that DANA87 and DANA88 are not only weak agonists of PPAR${\gamma}$ transactivation, but also competitively antagonize troglitazone-induced PPAR$\gamma$ reporter activity.