Fig. 8.

TGF-β signaling is required for the inhibitory effects of butein on adipocyte differentiation. A, B: Silencing TGF-β signaling blunted butein's inhibitory effects on adipocyte differentiation in 3T3-L1 cells. A: Differentiated cells were stained with Oil Red O. B: Knockdown of TGF-β signaling attenuated butein's effects on expression of adipocyte markers. Expression of PPARγ and its target gene aP2 in control (ctrl) and siRNA-transfected cells (si #1, si #2) treated with DMSO or butein (10 μM) was measured by real-time PCR. Data shown represent the mean ± SEM from three independent experiments. Statistical significance was determined relative to a control by the Student's t-test (*P < 0.05; **P < 0.005; ***P < 0.0005). C: Schematic diagram showing the mechanism by which butein regulates adipocyte differentiation.