Neutrophil extracellular traps promote the activation of the NLRP3 inflammasome and PBMCs pyroptosis via the ROS-dependent signaling pathway in Kawasaki disease

Kawasaki disease (KD) is an acute systemic vasculitis predominantly affecting infants and children under the age of 5. Recent studies have indicated that excessively released neutrophil extracellular traps (NETs) are involved in the progression of vasculitis. The purpose of this study was to investigate the role of NETs, especially their interaction with peripheral blood mononuclear cells (PBMCs), in the pathogenesis of KD. First, we demonstrated that the levels of NETs (cfDNA, MPO, and NE) in the serum of KD patients were significantly higher than those in healthy controls (HCs) and notably decreased after treatment. During the acute phase of KD, inflammatory markers (CRP and ESR) were positively correlated with NETs levels. Furthermore, we observed that neutrophils from KD patients in the acute phase produced elevated levels of NETs, and aspirin could effectively regulate the release of NETs. Additionally, NETs significantly increased the mRNA levels of NLRP3 and IL-1 beta in PBMCs, as well as the protein expression of NLRP3, caspase-1, ASC and gasdermin D, and the concentration of IL-1 beta in the cell supernatant. Moreover, NETs stimulated the production of reactive oxygen species (ROS) in PBMCs. N-acetylcysteine significantly reduced the expression of inflammatory factors and pyroptosis-related proteins in PBMCs. In conclusion, our findings suggest that NETs induce the generation of ROS, which in turn activates the NLRP3 inflammasome to mediate PBMCs pyroptosis and perpetuate inflammation in KD patients. This study reveals that targeting NETs or ROS could be a potential therapeutic approach for alleviating systemic inflammation, and that NETs may be a novel target for aspirin in the treatment of KD patients.