FIGURE 6.

Mitochondrial function and ROS metabolism are affected depending on the methylation state of quercetin. (A) Complex I-dependent OCR of mitochondria from ΔPaMth1 cultures treated with quercetin (Quer, n = 3 biological replicates, each with six technical replicates) compared to mitochondria from cultures treated with DMSO (Con; n = 3 biological replicates, each with five technical replicates). State 4 OCR of DMSO-treated mitochondria was set to 100%. (B) Complex I-dependent OCR of mitochondria from PaMth1_OEx cultures treated with quercetin (Quer, n = 3 biological replicates, each with five to six technical replicates) compared to mitochondria from cultures treated with DMSO (Con; n = 3 biological replicates, each with five technical replicates). State 4 OCR of DMSO-treated mitochondria was set to 100%. (C) Qualitative determination of superoxide anion release by a histochemical NBT staining and hydrogen peroxide release by a histochemical DAB staining in ΔPaMth1 and PaMth1_OEx cultures (n = 4) treated with quercetin (Quer) or DMSO (Con). (D) Quantification of H₂O₂ release measurement from P. anserina ΔPaMth1 cultures treated with quercetin (Quer; n = 4) compared to DMSO (Con; n = 4) treatment. The mean release of the DMSO-treated cultures was set to 1. (E) Quantification of H₂O₂ release measurement from P. anserina PaMth1_OEx cultures treated with quercetin (Quer; n = 4) compared to DMSO (Con; n = 4) treatment. The mean release of the DMSO-treated cultures was set to 1. (F) Representative “in-gel” SOD (PaSOD1 and PaSOD2) activity staining and (G) “in-gel” peroxidase activity staining from total protein extract of ΔPaMth1 and PaMth1_OEx cultures treated with quercetin (Quer; n = 4) or DMSO (Con; n = 4). Error bars correspond to the standard deviation and P-values were determined by two-tailed Student’s t-test. ^∗P < 0.05, ^∗∗P < 0.01, ^∗∗∗P < 0.001.