TGFB1 and idiopathic pulmonary fibrosis: In our study, the post-treatment with a PPAR-β/δ agonist (GW0742) alone or combined with a PPAR-γ agonist (rosiglitazone) strongly decreased the amount of TGF-β1-mediated increase in intracellular COL1 (Fig. 3A–C) by affecting COL1A2 promotor activity (Fig. 3D) as well as extracellular collagen (Fig. 3E) in both, fibroblasts from control and IPF patients.