Protocatechuic Acid-Ameliorated Endothelial Oxidative Stress through Regulating Acetylation Level via CD36/AMPK Pathway

As one of the main metabolites of anthocyanin, protocatechuic acid (PCA) possesses strong antioxidant activity. In the present study, we explored the capacity of PCA on the alleviation of endothelial oxidative stress and investigated the underlying mechanisms using RNA sequencing (RNA-Seq). In comparison with palmitic acid (PA)-treated cells, PCA (100 μM) significantly decreased the generations of 3-nitrotyrosine (3-NT) and 8-hydroxydeoxyguanosine (8-OHdG) (0.82 ± 0.01 vs 1.16 ± 0.05 and 0.80 ± 0.01 vs 1.48 ± 0.15, respectively, p < 0.01), two biomarkers of oxidative damage, and restored the levels of nitric oxide (NO) (0.97 ± 0.04 vs 0.54 ± 0.02, p < 0.01) and mitochondrial membrane potential (MMP) (0.96 ± 0.03 vs 0.86 ± 0.02, p < 0.01) in human umbilical vein endothelial cells (HUVECs). PCA also obviously reduced the level of Reactive Oxygen Species (ROS) (0.86 ± 0.15 vs 2.67 ± 0.09, p < 0.01) in aorta from high-fat diet (HFD)-fed mice. RNA-Seq and Western blot analysis indicated that PCA markedly reduced the expression of cluster of differentiation 36 (CD36), a membrane fatty acid transporter, and reduced the generations of adenosine triphosphate (ATP) and acetyl coenzyme A (Ac-CoA). These effects of PCA were associated with decreased level of acetylated-lysine and restored the activity of manganese-dependent superoxide dismutase (MnSOD) through reducing the generation of Ac-CoA or activating SIRT1 and SIRT3 via a CD36/AMP-kinase (AMPK) dependent pathway.