Figure 2

Anthocyanin-induced activation of AMPK is mediated by Ca²⁺ and CaMKK-β. (A) A representative trace of Ca²⁺ influx into HepG2 cells exposed to anthocyanin is illustrated. Fura-2-loaded cells were initially incubated with media and then switched to anthocyanin. Changes in [Ca²⁺]_i are expressed as the nM. n = 3. (B) HepG2 cells were exposed to media or Cy-3-g for 30 min in the presence or absence of BAPTA-AM (20 μM, 20-min preincubation). AMPK phosphorylation and total AMPK were determined by Western blot. Representative Western blot of pAMPK and total AMPK are shown. (C) HepG2 cells were exposed to culture medium (control) or Cy-3-g (100 μM) for 30 min in the presence or absence of STO-609 (20 μg/mL, 30-min preincubation). AMPK activity was determined as indicated. Values are expressed as fold of control. n = 4. *P < 0.05 between STO-609 and STO-60 plus Cy-3-g. (D) HepG2 cells were transfected with CaMKK-β siRNA (CaMKK-β si) or scrambled control siRNA (Control si), and 48 h later cells were exposed to medium or Cy-3-g (100 μM) for 30 min. Values are expressed as fold of control. n = 4. *P < 0.05 between Cy-3-g and CaMKK siRNA plus Cy-3-g.