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).