Fig. 6.

Lipin-1 increases APOB expression in exendin-4-treated cells. a HepG2 cells were transfected with 10 nM lipin-1 siRNA or control siRNA for 24 h and were pretreated with 3 μg/ml tunicamycin, followed by treatment with or without exendin-4 (Ex-4; 100 nM) for 24 h. APOB mRNA expression level was analyzed by performing quantitative RT-PCR. All values are expressed as the mean ± SE (n = 5–6). *p < 0.05 compared with control cells; ##p < 0.01 compared with tunicamycin-treated cells. b Schematic illustration of the signaling pathway discussed in this study