Figure 8. Activation of AMPKα blocks NgBR deficiency-induced LXRα activation and hepatic lipid accumulation.

(A, B) Activation of AMPKα blocks NgBR deficiency-induced nuclear translocation of LXRα in vitro. NgBR-deficient cells (shNgBRi) were treated with AICAR (1 mM) overnight followed by determination of LXRα localization by immunofluorescent staining (A). Both shNSi and shNgBRi cells were treated with metformin (10 μM) and AICAR (1 mM) overnight followed by determination of LXRα protein levels in cytosolic, nuclear, and whole cellular extracts by western blotting (B). (C-F) Littermate control and NgBR LivKO female mice at 8 weeks old were i.p. injected daily with saline (control) or metformin solution (250 mg/kg body weight/day) for one week. Total protein, RNA, lipid, and nuclear protein were prepared from mouse liver samples, for the following assays. Expression of phos-AMPKα, AMPKα, phos-ACC-1, and ACC-1 protein in total protein extract (C), expression of FASN, pSREBP-1c, nSREBP-1c, SCD-1, and LXRα protein in total protein extract, and LXRα protein in nuclear extract (E), expression of FASN, SCD-1, and SREBP-1c mRNA in total RNA (D), and TG and FFA levels in lipid extract (F) were determined by western blotting, real time RT-PCR, and assay kits. *: P<0.05 vs. control mice; #: P<0.05 vs. NgBR LivKO mice receiving saline injection (n=3).