NLRP3 inflammasome related signaling contributing to pathogenesis of Brugada Syndrome

Background Fever and inflammation can exacerbate the phenotype of Brugada syndrome (BrS). However, there is still a lack of experimental studies investigating the underlying mechanisms of fever or inflammation. NLRP3 (NOD-, LRR- and pyrin domain-containing protein 3) inflammasome is activated during infections. This study aimed to study the potential roles of the NLRP3 inflammasome in the effects of inflammation on the phenotype of BrS. Method The human induced pluripotent stem cell (hiPSC) lines were generated from fibroblasts of a BrS patient harboring a mutation (c.3148G>A, p.Ala1050Thr) in SCN5A, as well as from a healthy donor and a site-corrected (using CRISPR/CAS9) cell line. The hiPSC cell lines were used for the differentiation of cardiomyocytes (hiPSC-CMs). Arrhythmic events in BrS-hiPSC-CMs were assessed by calcium transient analysis. Sodium channel currents (INa) were measured by patch clamp. Western blotting was performed to measure SCN5A expression and NLRP3 signaling pathway. Result LPS significantly reduced peak INa and increased the incidence of arrhythmic-like events in BrS-hiPSC-CMs, indicating that inflammatory stimulation aggravates the BrS electrophysiological phenotype. Importantly, these effects were largely abolished by the selective NLRP3 inhibitor MCC950, demonstrating that NLRP3 inflammasome activation is required for LPS-induced sodium current suppression and arrhythmogenesis. To further establish pathway specificity, activation of NLRP3 or exogenous IL-18 treatment similarly reduced INa, thereby recapitulating the LPS-induced phenotype. Conversely, neutralization of IL-18 with IL-18 binding protein (IL-18BP) significantly restored INa under LPS stimulation, identifying IL-18 as a key downstream mediator of NLRP3 signaling in BrS cardiomyocytes. Given the emerging link between inflammation and metal-dependent cell stress, we next examined iron involvement. Notably, deferoxamine (DFO), an iron chelator, completely reversed the IL-18-induced reduction in INa, suggesting that iron-dependent mechanisms contribute to sodium channel dysfunction. At the molecular level, LPS decreased SCN5A expression in the membrane fraction, whereas MCC950 restored membrane-localized SCN5A abundance. Consistently, activation of the NLRP3 pathway was confirmed by increased expression of NLRP3, ASC, cleaved caspase-1, and N-terminal Gasdermin D. Conclusion These findings establish an NLRP3/IL-18/iron axis that impairs SCN5A membrane expression, suppresses INa, and promotes arrhythmogenic vulnerability in BrS-hiPSC-CMs.The NLRP3 inflammasome may contribute to arrhythmogenesis relating to inflammation in BrS patients. The NLRP3 inflammasome may be a potential therapeutic target for BrS.