Paeonol inhibits NETs-mediated foam cell inflammation through the CitH3/NLRP3/caspase-1 signaling pathway in atherosclerosis

Abstract

Atherosclerosis is a chronic inflammatory disease characterized by lipid streaks, which are produced by aggregates of lipid-rich foam cells. Foam cells intensify atherosclerosis by secreting a range of inflammatory mediators. Neutrophil extracellular traps produced by activated neutrophils, which are abundantly present in lipid-accumulating plaques. However, the relationship between neutrophil extracellular traps and foam cells inflammation is still unclear. Paeonol is well known for its anti-inflammatory effects in atherosclerosis. Nevertheless, the exact pharmacological mechanisms by which paeonol affects atherosclerosis are not fully understood which require further investigation. The purpose of this study is to investigate the effects of paeonol on the neutrophil extracellular traps' formation and foam cell inflammation caused by neutrophil extracellular traps, and to explore the potential mechanisms. A high-fat diet was administered to ApoE^−/− mice for a period of 12 weeks to induce an atherosclerosis model. Our findings demonstrated that paeonol notably suppressed the advancement of atherosclerosis in ApoE^−/− mice, curtailed the formation of neutrophil extracellular traps, and lowered inflammatory factor levels within the plaque. In vitro studies have shown that neutrophil extracellular traps could enhance the inflammation in foam cells. CitH3 played a role in the cellular communication between neutrophil extracellular traps and foam cells. Concurrently, NLRP3 acted as a key receptor in the inflammation mediated by this interaction. Paeonol is capable of regulating NE, thereby affecting the formation of neutrophil extracellular traps. Most notably, the foam cell inflammation caused by neutrophil extracellular traps was significantly mitigated by the inclusion of paeonol. Our findings suggested that paeonol inhibited foam cell inflammation which induced by neutrophil extracellular traps through the CitH3/NLRP3/caspase-1 signaling pathway, shedding new lights on its anti-atherosclerotic pharmacological mechanism.