Effects of adiponectin on the gene promoter activities of fatty acid synthase and hormone sensitive lipase in HepG2 cells

Objective To investigate the effects of adiponectin on human FAS and HSL gene promoter activities in human hepatocarcinoma cell line HepG2 transfected with plasmids containing human FAS or HSL promoters fused to a luciferase reporter gene. Methods The luciferase reporter gene expression plasmids pGL3-hFAS625-Luc(hFAS 625-Luc) and pGL3-hHSL750-Luc (hHSL 750-Luc) were constructed. HepG2 cells were then transfected with these plasmids by lipofectamine method. The FAS and HSL promoter activities was evaluated by testing the luciferase activity through incubation with 0.5-10.0 μg/mL adiponectin) for 24 h or 5 μg/mL adiponectin for 2-32 h. Results Both hFAS 625-Luc and hHSL 750-Luc plasmids were well expressed in HepG2 cells. 1.0-10.0 μg/mL adiponectin could progressively increase the luciferase expression in HepG2 cells transfected with hFAS 625-Luc and hHSL 750-Luc plasmids with the maximum effect of 1.76 folds (P＜0.01) and 1.37 folds of the controls, respectively, at the concentration of 10.0 μg/mL(P＜0.01). Moreover, 5 μg/mL adiponectin promoted the expression of luciferase in HepG2 cells transfected with hFAS 625-Luc plasmids at 4 h and 8 h (P＜0.01), and inhibited the expression of luciferase at 16 h and 32 h (P＜0.01). Adiponectin promoted the expression of luciferase in HepG2 cells transfected with HSL 750-Luc within different durations(2~32 h), and the highest was 1.37 times of the control group at 2 h (P＜0.01). Conclusions The luciferase reporter gene plasmids containing human FAS and HSL promoters are successfully constructed. Adiponectin promotes FAS and HSL promoter activities in HepG2 cells with a dose-dependent manner. Adiponectin has a double effect on FAS promoter activity in different times, while it has a promoting effect on HSL promoter activity with different incubation durations.