Fig. 4.

Influences of co-treatment with ATRA and ellagic acid or urolithin A on protein levels of the O₂⁻-generating system-related factors. (A) Typical immunoblot profiles. Cytosolic (for p40-phox, p47-phox and p67-phox) and membrane (for p22-phox and gp91-phox) fractions were prepared from ATRA-treated (lane 1), ATRA plus ellagic acid-treated (lane 2) and ATRA plus urolithin A-treated (lane 3) U937 cells, and protein levels were determined by immunoblotting as in “Materials and methods.” Human β-actin (for cytosolic fractions) and Na⁺/K⁺-ATPase (for membrane fractions) were used as controls. Quantitative data of ATRA plus ellagic acid-treated (B) and ATRA plus urolithin A-treated (C) U937 cells are indicated as percentages of control values (100%) obtained from ATRA-treated U937 cells, and represent the averages of three separate experiments. Error bars indicate standard deviation. **, P < 0.01 compared with the data of ATRA-treated cells.