FIGURE 2.

Resveratrol increases intracellular calcium levels and promotes CaMKKβ-dependent phosphorylation of AMPK. A, shown are intracellular ATP levels in APP-HEK293 cells treated for 1 or 24 h with the indicated concentrations of resveratrol (RSV) or with 2-deoxy-d-glucose + antimycin A (2DG/AM; used as control for ATP production inhibition). B, shown are WB analyses of pAMPK, AMPK, actin, and LKB1 levels in HEK293 (lane 1) and HeLa (lanes 2–6) cells treated with the indicated concentrations of resveratrol. C, shown are cytosolic calcium measurements with Fluo-4 loading and calcium add-back conditions in APP-HEK293 cells treated for 24 h with the indicated concentrations of RSV. Cells were incubated in calcium-free buffer (0 CaCl₂) and then challenged with physiological extracellular calcium concentrations (1.4 mm CaCl₂) to monitor the progressive restoration of basal cytoplasmic calcium levels. Traces illustrate the mean relative fluorescence units (RFU) ± S.D. (shaded area) of three independent experiments. CTRL, control. D, peak and steady state of cytosolic calcium measurements are as in C, expressed in ΔF/F₀. Histograms show the mean ± S.D. of three independent experiments. *, p < 0.001 (Student's t test). E, shown are cytosolic calcium measurements in cells treated with RSV as in C and incubated with 2 μm thapsigargin in calcium-free buffer. F, shown are WB analyses of pAMPK, pACC, and actin levels in APP-HEK293 cells incubated for 24 h with the indicated concentrations of STO-609 and in the absence (−) or presence (+) of 40 μm RSV.