HDAC5 was involved in the regulation of ECFCs by the AMPK-KLF2 pathway. (A) ECFCs were incubated in the presence or absence of VEGF (25 ng/mL) and AICAR (1 mM) for 1 or 24 h, as indicated. Western blot analysis of levels of phosphorylated and unphosphorylated AMPK and HDAC5, MEF2, and KLF2. β-actin was an internal control. (B) ECFCs were pre-treated with dimethyl sulfoxide or Compound C (10 μM) for 30 min and further incubated with or without VEGF (25 ng/mL) for 1 h. Western blot analysis of the levels of phosphorylated AMPK, eNOS, and HDAC5. β-actin was an internal control. (C) siRNA knockdown of HDAC5 in ECFCs. Western blot analysis of protein levels of eNOS, KLF2 MEF2, and HDAC5. β-actin was an internal control. Data are mean ± SD from three independent experiments, each performed in triplicate (*P < 0.05; **P < 0.01).