Analysis of the role of Na_v1.5 slow inactivation in the development of inherited cardiac pathology

Abstract

Voltage-gated cardiac sodium channels Nav1.5 are responsible for the initiation and propagation of action potentials in cardiomyocytes. Dysfunction of Nav1.5 can be caused both by pathogenic variants in the SCN5A gene itself, which encodes Nav1.5, and by genetic variants in the genes of other proteins, regulating channel activity and trafficking. The change of different phases of the action potential is determined by the strict temporal organization of activation and inactivation of various ion channels. Transitions between channel functional states (for example, to slow inactivated state) can be influenced by various factors and proteins interacting with the channel. Despite the fact that the process of slow inactivation of the channel has been known for several decades, its role in the mechanism of development of hereditary heart pathology remains unclear. In this work, using the patch clamp method in whole-cell leads, we studied changes in the process of slow Nav1.5 inactivation under the influence of various mutations in structural genes (DSP-H1684R, LMNA-R249Q, FLNC-R1267Q, FLNC-V2264M) associated with a genetically determined myocardial pathology leading to dysfunction of cardiomyocytes. The study used a model of cardiomyocytes differentiated from induced pluripotent stem cells (СM-iPSCs). We have demonstrated an increase in slow inactivation in the model of CM-iPSCs obtained from patients with a phenotype of cardiomyopathy combined with ventricular arrhythmias. Thus, this work contributes to understanding the role of the slow inactivation process in the mechanism of the development of heart pathology.