FIGURE 6.

AMPK is required for SIRT1 to suppress FAS induction and lipid accumulation in HepG2 cells exposed to high glucose. HepG2 cells were infected with adenoviral vectors encoding GFP or a Myc-tagged dominant-negative AMPK mutant (Ad-DN-AMPK, AMPKαK45R) or co-infected with Ad-SIRT1 and subsequently incubated for 24 h without or with resveratrol (10 μm) in the absence or presence of high glucose. A, overexpression of the DN-AMPK (∼64 kDa) and SIRT1 (∼120 kDa) was confirmed by immunoblots with anti-Myc and anti-AMPKα2 and with anti-SIRT1 antibodies, respectively. B and C, the ability of SIRT1 to prevent the decrease in ACC phosphorylation caused by high glucose is attenuated by the DN-AMPK. D and E, SIRT1 suppression of high glucose-enhanced FAS expression is abrogated by the DN-AMPK. F, DN-AMPK blocks the effect of SIRT1 and resveratrol on lipid accumulation. *, p < 0.05 versus normal glucose in cells expressing GFP; #, p < 0.05 versus high glucose alone in cells expressing GFP; ##, p < 0.05 versus polyphenol treatment in cells expressing GFP (mean ± S.E., n = 4).