Quercetin alleviates atherosclerosis by suppressing oxidized LDL-induced senescence in plaque macrophage via inhibiting the p38MAPK/p16 pathway

Quercetin is a widely known and biologically active phytochemical and exerts therapeutic effects against atherosclerosis. The removal of senescent plaque macrophages effectively slows the progression of atherosclerosis and decreases the plaque burden. Still, whether quercetin alleviates atherosclerosis by inhibiting the senescence of plaque macrophages, including the potential mechanisms, remains unclear. ApoE-/- mice were fed with a normal chow diet or high-fat diet (HFD) supplemented or not with quercetin (100 mg/kg of body weight) for 16 weeks. An accumulation of senescent macrophages was observed in the plaque-rich aortic tissues from the mice with HFD, but quercetin supplementation effectively reduced the amount of senescent plaque macrophage, inhibited the secretion of key senescence-associated secretory phenotype factors, and alleviated atherosclerosis by inhibiting p38MAPK phosphorylation and p16 expression. In vitro, SB203580 (a specific inhibitor of p38 MAPK) significantly inhibited oxidized low-density lipoprotein (ox-LDL)-induced senescence in mouse RAW264.7 macrophages, as evidenced by decreased senescence-associated markers (SA-β-gal staining positive cells and p16 expression). Furthermore, quercetin not only effectively reversed ox-LDL-induced senescence in RAW264.7 cells but also decreased the mRNA levels of several key senescence-associated secretory phenotype factors by suppressing p38 MAPK phosphorylation and p16 expression. The p38 MAPK agonist Asiatic acid reversed the effects of quercetin. In conclusion, these findings indicate that quercetin suppresses ox-LDL-induced senescence in plaque macrophage and attenuates atherosclerosis by inhibiting the p38 MAPK/p16 pathway. This study elucidates the mechanisms of quercetin against atherosclerosis and supports quercetin as a nutraceutical for the management of atherosclerosis.