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. 2008 Jul 18;283(29):20015–20026. doi: 10.1074/jbc.M802187200

FIGURE 4.

FIGURE 4.

Polyphenol-induced AMPK activation and lipid reduction is abolished by overexpression of a catalytically inactive mutant of SIRT1 (SIRT1H355A) in HepG2 cells. A, a representative immunoblot of overexpression of an adenovirus vector encoding a catalytically inactive SIRT1 mutant in HepG2 cells is shown. B, polyphenol-stimulated AMPK phosphorylation is abolished by the SIRT1H355A mutant under normal glucose conditions. HepG2 cells were infected for 48 h with Ad-GFP or Ad-SIRT1H355A, followed by treatment with S17834 (10 μm) or resveratrol (50 μm) for 1 h. C and D, polyphenol-stimulated AMPK signaling is diminished by the SIRT1H355A mutant under high glucose conditions. HepG2 cells infected with Ad-GFP or Ad-SIRT1H355A were quiesced in serum-free medium overnight and treated for 24 h without or with 10 μm of resveratrol or S17834 in the presence of high glucose. E, the lipid-lowering effect of resveratrol is attenuated by the SIRT1H355A mutant. *, 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).