Fig. 5.

Knockdown of the IRE1α gene with siRNA reduced lipogenic program in hepatocytes. A, The siRNA against the IRE1α gene or the scrambled siRNA were introduced into hepa1c1c7 cells for 48 h followed by evaluating levels of IRE1α proteins by immunoblotting with noted antibodies. B, The FAS promoter was introduced into hepa1c1c7 cells with the noted siRNA via transient transfection for 36 h. Promoter activity was stimulated by insulin (10 nm) for 6 h, measured by luciferase assays, and normalized to the protein level. C, The siRNA against IRE1α were introduced into isolated primary hepatocytes as described in Fig. 3. After 16 h, cells were exposed to insulin (10 nm) for 48 h (fresh insulin was added every 12 h to maintain the concentration of insulin). TG content was measured and normalized to the protein level. Results represent mean ± sem of three independent experiments, each in triplicate.