Figure 3
The effect of OxLDL on Hsp70 protein expression is dependent on PPARγ. (A) U937 mock-transfectants were pre-incubated in 1 ml of SFM in the absence or presence of PGF2α (0.1 µM) for 1 h, prior to incubation in the absence or presence of OxLDL (80 µg/ml). After 8 h, expression levels of Hsp70 protein were evaluated by Western blot analysis. (B) U937 mock-transfectants were treated as in (A) and then analyzed for Hsp70 mRNA expression by Northern blot analysis. GAPDH bands were detected as loading controls. (C) U937 CD36 ΔN/C transfectants were pre-incubated in 1 ml of SFM in the absence or presence of ciglitazone (5 µM) for 1 h and then treated as in (A). Expression levels of Hsp70 protein were evaluated by Western blot (WB) analysis. (D) After treated as in (C), U937 CD36 ΔN/C transfectants were collected and analyzed for Hsp70 mRNA expression by Northern blot analysis. (E) U937 cells were transiently transfected with PPARγ or CD36 siRNA. After transfection, the cells were incubated for 24 h in SFM and then analyzed for PPARγ mRNA expression by Northern blot analysis. GAPDH bands were detected as loading controls. (F) U937 cells were transiently transfected with either PPARγ or control GAPDH siRNA. After transfection, cells were treated with OxLDL (80 µg/ml) for 8 h. Induction levels of Hsp70 protein were then determined by Western blot analysis, with β-actin levels serving as loading controls. Relative expression levels of Hsp70 are shown as values relative to Hsp70 expression levels of untreated controls (designated as 100%).
