Hypertrophic cardiomyopathy-linked mutation in troponin T causes myofibrillar disarray and pro-arrhythmic action potential changes in human iPSC cardiomyocytes.
J Mol Cell Cardiol
; 114: 320-327, 2018 01.
Article
en En
| MEDLINE
| ID: mdl-29217433
ABSTRACT
BACKGROUND:
Mutations in cardiac troponin T (TnT) are linked to increased risk of ventricular arrhythmia and sudden death despite causing little to no cardiac hypertrophy. Studies in mice suggest that the hypertrophic cardiomyopathy (HCM)-associated TnT-I79N mutation increases myofilament Ca sensitivity and is arrhythmogenic, but whether findings from mice translate to human cardiomyocyte electrophysiology is not known.OBJECTIVES:
To study the effects of the TnT-I79N mutation in human cardiomyocytes.METHODS:
Using CRISPR/Cas9, the TnT-I79N mutation was introduced into human induced pluripotent stem cells (hiPSCs). We then used the matrigel mattress method to generate single rod-shaped cardiomyocytes (CMs) and studied contractility, Ca handling and electrophysiology.RESULTS:
Compared to isogenic control hiPSC-CMs, TnT-I79N hiPSC-CMs exhibited sarcomere disorganization, increased systolic function and impaired relaxation. The Ca-dependence of contractility was leftward shifted in mutation containing cardiomyocytes, demonstrating increased myofilament Ca sensitivity. In voltage-clamped hiPSC-CMs, TnT-I79N reduced intracellular Ca transients by enhancing cytosolic Ca buffering. These changes in Ca handling resulted in beat-to-beat instability and triangulation of the cardiac action potential, which are predictors of arrhythmia risk. The myofilament Ca sensitizer EMD57033 produced similar action potential triangulation in control hiPSC-CMs.CONCLUSIONS:
The TnT-I79N hiPSC-CM model not only reproduces key cellular features of TnT-linked HCM such as myofilament disarray, hypercontractility and diastolic dysfunction, but also suggests that this TnT mutation causes pro-arrhythmic changes of the human ventricular action potential.Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Arritmias Cardíacas
/
Cardiomiopatía Hipertrófica
/
Potenciales de Acción
/
Troponina T
/
Miocitos Cardíacos
/
Células Madre Pluripotentes Inducidas
/
Mutación
/
Miofibrillas
Tipo de estudio:
Etiology_studies
/
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
J Mol Cell Cardiol
Año:
2018
Tipo del documento:
Article
País de afiliación:
Estados Unidos