Protective role of forsythoside B in Kawasaki disease-induced cardiac injury: Inhibition of pyroptosis via the SIRT1–NF-κB–p65 signaling pathway

Kawasaki disease (KD), an acute exanthematous febrile pediatric illness involving systemic non-specific inflammatory reactions in small- and medium-sized arteries, poses a significant risk of coronary artery and myocardial inflammatory injury. Developing new KD treatments with improved safety and fewer side-effects is highly desirable. Forsythoside B (FTS-B), extracted from the Forsythia suspensa plant, exerts anti-inflammatory activity by inhibiting NF-κB, which is regulated by SIRT1, the reduced expression of which is strongly associated with cardiovascular disease. However, it has yet to be established whether FTS-B influences KD-related inflammatory damage. In this study, we investigated the effects of FTS-B on inflammation in cellular and murine models of KD. Our findings revealed that KD is associated with cardiac dysfunction and inflammatory injury to myocardial and human coronary artery endothelial cells (HCAECs), resulting in a pyroptosis-feedback loop. Both cellular and KD models were characterized by reduced SIRT1 expression and increased NF-κB p65 expression. Contrastingly, the rates of pyroptosis in both murine model myocardial tissues and HCAECs were significantly alleviated in response to FTS-B treatment. Also in both models, we detected an increase of SIRT1 expression and a decrease in the expression of p65. Further examination of the protective mechanism of FTS-B using the SIRT1-specific inhibitor, EX 527, revealed that this inhibitor blocked the palliative effects of FTS-B on inflammatory injury-induced pyroptosis. These results highlight the potential utility of the SIRT1–NF-κB–p65 pathway as a therapeutic target for KD treatment and demonstrate that FTS-B can alleviate KD-induced cardiac and HCAEC inflammatory injury via inhibition of pyroptosis.