FIGURE 4.

STAT1 is necessary for IFNγ-induced lipocalin-2 expression in adipocytes. 3T3-L1 adipocytes were transfected with 100 nm STAT1 siRNA or non-targeting siRNA. A, 24 h later, total RNA was purified and analyzed by real time PCR. B, after 40 h, cells were serum-deprived for 24 h and treated with 100 ng/ml IFNγ. Total RNA was isolated 16 h later and subjected to quantitative real time PCR. Cyclophilin A (PPIA) was used as an endogenous control. C, 40 h after transfection, adipocytes were serum-deprived for 24 h and treated with 100 ng/ml IFNγ. Whole cell extracts were obtained after 24 h, and 150 μg of protein was analyzed by Western blot. Western blots were quantified with ImageJ. Each panel is representative of an experiment that was independently performed three times. ***, p < 0.001. Error bars represent S.D. AU, arbitrary units; CTL, control; NT, non-targeting; KD, knockdown.