Brd4 regulated FoxO4 expression via the PI3K/AKT pathway. (A–B) Western blot analysis for the protein expression of PI3K, p-PI3K, AKT, p-AKT in the indicated groups and quantitative analysis of p-PI3K and p-AKT. *P < 0.05 versus control, #P < 0.05 versus H/R+JQ1, & P < 0.05 versus H/R+si-NC. (C–D) HK-2 cells were pretreated with JQ1 (10 μM) for 1 h following treatment with LY294002 (PI3K inhibitor, 20 μM) and then exposed to H/R. (C) Western blot analysis for the protein expression of FoxO4 in the indicated groups and quantification, *P < 0.05 versus H/R+JQ1. (D) Luciferase assay of FoxO4 promoter activity in the presence of JQ1 or Brd4 knockdown with siRNA or combination of JQ1 and LY294002 from three independent experiments, each performed in six replicates. *P < 0.05 versus H/R, #P < 0.05 versus H/R+si-NC, & P < 0.05 versus H/R+si-Brd4.