NLRP3 Inflammasome is Involved in Pathomechanism of Brugada Syndrome

Chen Yan (Mannheim)1, Z. Meng (Mannheim)1, X. Lei (Mannheim)1, X. Fan (Mannheim)1, L. Cyganek (Göttingen)2, I. EI-Battrawy (Bochum)3, X. Zhou (Mannheim)1, I. Akin (Mannheim)1

1Universitätsklinikum Mannheim I. Medizinische Klinik Mannheim, Deutschland; 2Universitätsmedizin Göttingen Herzzentrum Göttingen - Stem Cell Unit Göttingen, Deutschland; 3Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil Medizinische Klinik II, Kardiologie und Angiologie Bochum, Deutschland


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 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). qPCR analysis was conducted to measure the mRNA level of PKC subtype (PKC α, PKC β, and PKC ε) after treatment with LPS or LPS plus MCC950, an NLRP3 inflammasome inhibitor. Arrhythmic events in BrS-hiPSC-CMs and healthy or isogenic control were assessed by calcium transient analysis. Sodium channel currents (INa) were measured by patch clamp. Western Blotting was performed to measure SCN5A expression.

Result: LPS reduced peak INa and increased the number of cells displaying arrhythmic events in BrS-hiPSC-CMs but not in healthy donor-hiPSC-CMs, implying that LPS can exacerbate the BrS phenotype. LPS increased the expression level of PKC subtypes (PKC-a, PKC-b, and PKC-e) in healthy donor-hiPSC-CMs and isogenic cells, but reduced their expression in BrS-hiPSC-CMs, indicating an involvement of protein kinase C (PKC) in LPS effects. Strikingly, the LPS effects on PKC level could be inhibited by the NLRP3 inflammasome inhibitor (MCC950). Additionally, the arrhythmia-enhancing effect of LPS was also inhibited by MCC950.The LPS inhibitory effect on peak INa and SCN5A expression could be reversed by MCC950.

Conclusion: The NLRP3 inflammasome may contribute to arrhythmogenesis relating to inflammation in BrS patients by reducing PKC α, PKC β, and PKC ε. The NLRP3 inflammasome may be a potential therapeutic target for BrS. 

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