Figure 6.

Effect of G. cambogia extract on SQSTM1-mediated selective autophagic degradation of KLF3 in 3T3-L1 preadipocytes during differentiation. (A) Interaction of SQSTM1 and KLF3 in 3T3-L1 differentiated cells treated with G. cambogia extract (Ga, 300 μg/ml), FMK (3 μM) and stattic (5 μM) for 72 h. Coimmunoprecipitation (IP) was used to analyze the level of SQSTM1 that physically interacted with KLF3. The lysates were immunoprecipitated with anti-KLF3 and anti-IgG antibodies, and the precipitates were analyzed by western blotting using antibodies against SQSTM1 and KLF3 (n = 4 per group). (B) Effect of Sqstm1 knockdown on the interaction of SQSTM1 and KLF3 in 3T3-L1 differentiated cells treated with G. cambogia extract (300 μg/ml). Sqstm1 knockdown cells were treated with G. cambogia extract (300 μg/ml) for 72 h (n = 4 per group). (C) Effect of Sqstm1 knockdown on LC3, SQSTM1, KLF3, CEBPA and PPARG expression in 3T3-L1 differentiated cells treated with G. cambogia extract (300 μg/ml) for 72 h in the presence or absence of rapamycin (Ra, 10 nM) for 24 h (n = 4 per group). (D) Fluorescence photographs (left) and quantification data (below) of LC3 and KLF3 in Sqstm1 knockdown cells treated with G. cambogia extract (300 μg/ml) for 72 h in the presence or absence of rapamycin (10 nM) for 24 h. The fluorescence intensity of FITC (i.e., LC3) and TRITC (i.e., KLF3) was quantified using ImageJ software and colocalization (yellow dots indicated by white arrows) of FITC and TRITC per cell was determined and analyzed (n = 5 per group). Scale bars: 5 μm (E) Effect of Sqstm1 knockdown on G. cambogia extract- and rapamycin-mediated lipid accumulation in mature 3T3-L1 adipocytes (n = 12 per group). During full differentiation (day 0–8), cells were treated with G. cambogia extract (300 μg/ml), and rapamycin (10 nM) was added at day 3–8. Con: undifferentiated cells, Diff: mature 3T3-L1 adipocytes. *p < 0.05 and **p < 0.01 vs. each group. n.s.: not significant. The data are the mean ± S.D.