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Remodeling of repolarization and arrhythmia susceptibility in a myosin-binding protein C knockout mouse model
Journal article   Open access   Peer reviewed

Remodeling of repolarization and arrhythmia susceptibility in a myosin-binding protein C knockout mouse model

Amir Toib, Chen Zhang, Giulia Borghetti, Xiaoxiao Zhang, Markus Wallner, Yijun Yang, Constantine D Troupes, Hajime Kubo, Thomas E Sharp, Eric Feldsott, …
American journal of physiology. Heart and circulatory physiology, v 313(3), pp H620-H630
01 Sep 2017
PMID: 28646025
url
https://doi.org/10.1152/ajpheart.00167.2017View
Published, Version of Record (VoR)Maybe Open Access (Publisher Bronze) Open

Abstract

Action Potentials Animals Cardiomegaly - genetics Cardiomegaly - metabolism Cardiomegaly - pathology Carrier Proteins - genetics Carrier Proteins - metabolism Disease Models, Animal Electrocardiography, Ambulatory Fibrosis Genetic Predisposition to Disease Heart Rate Kinetics Male Mice, 129 Strain Mice, Knockout Myocardial Contraction Myocytes, Cardiac - metabolism Myocytes, Cardiac - pathology Patch-Clamp Techniques Phenotype Potassium - metabolism Potassium Channels - genetics Potassium Channels - metabolism RNA, Messenger - genetics RNA, Messenger - metabolism Tachycardia, Ventricular - genetics Tachycardia, Ventricular - metabolism Tachycardia, Ventricular - pathology Tachycardia, Ventricular - physiopathology Telemetry Ventricular Premature Complexes - genetics Ventricular Premature Complexes - metabolism Ventricular Premature Complexes - pathology Ventricular Premature Complexes - physiopathology
Hypertrophic cardiomyopathy (HCM) is one of the most common genetic cardiac diseases and among the leading causes of sudden cardiac death (SCD) in the young. The cellular mechanisms leading to SCD in HCM are not well known. Prolongation of the action potential (AP) duration (APD) is a common feature predisposing hypertrophied hearts to SCD. Previous studies have explored the roles of inward Na and Ca in the development of HCM, but the role of repolarizing K currents has not been defined. The objective of this study was to characterize the arrhythmogenic phenotype and cellular electrophysiological properties of mice with HCM, induced by myosin-binding protein C (MyBPC) knockout (KO), and to test the hypothesis that remodeling of repolarizing K currents causes APD prolongation in MyBPC KO myocytes. We demonstrated that MyBPC KO mice developed severe hypertrophy and cardiac dysfunction compared with wild-type (WT) control mice. Telemetric electrocardiographic recordings of awake mice revealed prolongation of the corrected QT interval in the KO compared with WT control mice, with overt ventricular arrhythmias. Whole cell current- and voltage-clamp experiments comparing KO with WT mice demonstrated ventricular myocyte hypertrophy, AP prolongation, and decreased repolarizing K currents. Quantitative RT-PCR analysis revealed decreased mRNA levels of several key K channel subunits. In conclusion, decrease in repolarizing K currents in MyBPC KO ventricular myocytes contributes to AP and corrected QT interval prolongation and could account for the arrhythmia susceptibility. Ventricular myocytes isolated from the myosin-binding protein C knockout hypertrophic cardiomyopathy mouse model demonstrate decreased repolarizing K currents and action potential and QT interval prolongation, linking cellular repolarization abnormalities with arrhythmia susceptibility and the risk for sudden cardiac death in hypertrophic cardiomyopathy.

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Collaboration types
Domestic collaboration
Web of Science research areas
Cardiac & Cardiovascular Systems
Peripheral Vascular Disease
Physiology
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