Protocatechuic Acid Prevents oxLDL-Induced Apoptosis by Activating JNK/Nrf2 Survival Signals in Macrophages

Figure 6

Protocatechuic acid activation of JNK and JNK-dependent activation of Nrf2 lead p53-dependent apoptosis inhibition. Blotting analyses of (a) serine-phosphorylated p53 (1 h after oxLDL treatment) detected in anti-p53 immunoprecipitate and normalized to the nonphosphorylated protein. (b) Bax protein expression (18 h after oxLDL treatment), normalized to cyclophilin protein. (c) caspase-3 active form expression (18 h after oxLDL treatment) normalized to cyclophilin protein. Values obtained in oxLDL-treated cells were compared with values obtained in (i) cells treated with oxLDL and PCA or (ii) cells treated with oxLDL and PCA in the presence of the JNK1/2 inhibitor SP600125 or cells treated with (iii) oxLDL and PCA transfected with anti-Nrf2 siRNA or (iv) the corresponding scrambled RNAs. The inhibitor tested on control cells and oxLDL-treated cells did not show any effect (data not shown). Representative blots from at least three independent experiments are shown. Results are expressed as mean ± S.E.M.; versus controls; versus oxLDL-treated cells.

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