Details

Autor(en) / Beteiligte

• Rodríguez, Nelson A
• Patel, Nihir
• Dariolli, Rafael
• Ng, Simon
• Aleman, Angelika G
• Gong, Jingqi Q X
• Lin, Hung-Mo
• Rodríguez, Matthew
• Josowitz, Rebecca
• Sol-Church, Katia
• Gripp, Karen W
• Lin, Xianming
• Song, Soomin C
• Fishman, Glenn I
• Sobie, Eric A
• Gelb, Bruce D

Titel

HRAS -Mutant Cardiomyocyte Model of Multifocal Atrial Tachycardia

Ist Teil von

• Circulation. Arrhythmia and electrophysiology, 2024-04, Vol.17 (4), p.e012022

Ort / Verlag

United States

Erscheinungsjahr

2024

Quelle

MEDLINE

Beschreibungen/Notizen

• Germline gain-of-function pathogenic variants cause Costello syndrome (CS). During early childhood, 50% of patients develop multifocal atrial tachycardia, a treatment-resistant tachyarrhythmia of unknown pathogenesis. This study investigated how overactive HRAS activity triggers arrhythmogenesis in atrial-like cardiomyocytes (ACMs) derived from human-induced pluripotent stem cells bearing CS-associated variants. Gly12 mutations were introduced into a human-induced pluripotent stem cells-ACM reporter line. Human-induced pluripotent stem cells were generated from patients with CS exhibiting tachyarrhythmia. Calcium transients and action potentials were assessed in induced pluripotent stem cell-derived ACMs. Automated patch clamping assessed funny currents. HCN inhibitors targeted pacemaker-like activity in mutant ACMs. Transcriptomic data were analyzed via differential gene expression and gene ontology. Immunoblotting evaluated protein expression associated with calcium handling and pacemaker-nodal expression. ACMs harboring variants displayed higher beating rates compared with healthy controls. The hyperpolarization activated cyclic nucleotide gated potassium channel inhibitor ivabradine and the Na 1.5 blocker flecainide significantly decreased beating rates in mutant ACMs, whereas voltage-gated calcium channel 1.2 blocker verapamil attenuated their irregularity. Electrophysiological assessment revealed an increased number of pacemaker-like cells with elevated funny current densities among mutant ACMs. Mutant ACMs demonstrated elevated gene expression (ie, , , ) related to intracellular calcium homeostasis, heart rate, RAS signaling, and induction of pacemaker-nodal-like transcriptional programming. Immunoblotting confirmed increased protein levels for genes of interest and suppressed MAPK (mitogen-activated protein kinase) activity in mutant ACMs. CS-associated gain-of-function mutations in induced pluripotent stem cells-derived ACMs trigger transcriptional changes associated with enhanced automaticity and arrhythmic activity consistent with multifocal atrial tachycardia. This is the first human-induced pluripotent stem cell model establishing the mechanistic basis for multifocal atrial tachycardia in CS.