Molecular and Functional Relevance of NaV1.8-Induced Atrial Arrhythmogenic Triggers in a Human SCN10A Knock-Out Stem Cell Model

Abstract

In heart failure and atrial fibrillation, a persistent Na+ current (INaL) exerts detrimental effects on cellular electrophysiology and can induce arrhythmias. We have recently shown that NaV1.8 contributes to arrhythmogenesis by inducing a INaL. Genome-wide association studies indicate that mutations in the SCN10A gene (NaV1.8) are associated with increased risk for arrhythmias, Brugada syndrome, and sudden cardiac death. However, the mediation of these NaV1.8-related effects, whether through cardiac ganglia or cardiomyocytes, is still a subject of controversial discussion. We used CRISPR/Cas9 technology to generate homozygous atrial SCN10A-KO-iPSC-CMs. Ruptured-patch whole-cell patch-clamp was used to measure the INaL and action potential duration. Ca2+ measurements (Fluo 4-AM) were performed to analyze proarrhythmogenic diastolic SR Ca2+ leak. The INaL was significantly reduced in atrial SCN10A KO CMs as well as after specific pharmacological inhibition of NaV1.8. No effects on atrial APD90 were detected in any groups. Both SCN10A KO and specific blockers of NaV1.8 led to decreased Ca2+ spark frequency and a significant reduction of arrhythmogenic Ca2+ waves. Our experiments demonstrate that NaV1.8 contributes to INaL formation in human atrial CMs and that NaV1.8 inhibition modulates proarrhythmogenic triggers in human atrial CMs and therefore NaV1.8 could be a new target for antiarrhythmic strategies.

NaV1.8 as Proarrhythmic Target in a Ventricular Cardiac Stem Cell Model

“…iPSC-CM were incubated with either Iso (50 nmol/L, or Iso + PF-01247324 (1 µmol/L, Sigma-Aldrich, Taufkirchen, Germany) for 15 min before starting measurements. Regarding the specificity of Na V 1.8 blockers, there are already published data that have demonstrated the specificity of PF-01247324 and showed that it is an efficacious inhibitor of Na V 1.8 [ 21 , 22 , 73 , 74 ].…”

“…Patch-clamp experiments were performed as previously described [ 21 , 22 , 74 , 75 ]. For action potential recordings, we employed the whole-cell patch-clamp technique in the current clamp configuration.…”

Molecular Study of Sudden Cardiac Death

“…One such study, published as part of the present Special Issue, performed by Hartman et al aimed to investigate the electrophysiological contribution of Na V 1.8 (a voltage-gated sodium channel) to the generation of atrial arrhythmogenesis by using a human SCN10A knock-out stem cell model. The results of the study conclusively showed that Na V 1.8 inhibition can modulate pro-arrhythmogenic triggers in atrial cardiomyocytes, suggesting its potential usefulness as a target in arrhythmogenic strategies [ 19 ]. The results of this particular study thus confirm the results of other studies in this research field, which may soon have significant therapeutic implications [ 20 ].…”

Noncoding RNAs and Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes in Cardiac Arrhythmic Brugada Syndrome

“…This impacts Na V 1.5 function, cardiac conduction velocities, and arrhythmia susceptibility. A recent study has shown that the SCN10A gene (Na V 1.8) contributes to I NaL formation in human atrial cardiomyocytes, and CRISPR/Cas9 deletion of this gene modulates proarrhythmogenic triggers in human atrial cardiomyocytes [167].…”