FIGURE 8.

Specific caspase-8 inhibitor, Z-IETD-fmk, but not the pan-caspase inhibitor, Z-VAD-fmk, inhibits palmitate-induced ER stress. Huh-7 cells were treated with PA at 400 or 800 μm or vehicle (V) for 8 h. Caspase-8 activity was inhibited using the specific inhibitor Z-IETD-fmk (10 μm) or the pan-caspase inhibitor Z-VAD-fmk (10 μm). A and B, total RNA was isolated, and CHOP mRNA was quantified by real time PCR. Fold induction is relative to internal control 18 S. Data represent mean ± S.E. of three experiments; *, p < 0.05. C, whole cell lysates were prepared, and immunoblot analysis was performed for caspase-8 (C8), phosphorylated JNK (p-JNK), total JNK (t-JNK), and β-actin, a control for protein loading. D, spliced Xbp-1 (Xbp-1s) was detected by RT-PCR followed by digestion by Pst-I. E, cells were treated with PA at 800 μm or vehicle (V) for 8 h. DR5 mRNA was quantified by real time PCR relative to internal control 18 S. Data represent mean ± S.E. of three experiments; *, p < 0.05.