CRISPR correction of the PRKAG2 gene mutation in the patient's iPSC-derived cardiomyocytes eliminates the electrophysiological and structural abnormalities

BACKGROUND: Mutations in the PRKAG2 gene encoding the {gamma}-subunit of adenosine monophosphate-kinase (AMPK) cause hypertrophic cardiomyopathy (HCM) and familial-Wolff-Parkinson-White syndrome (WPW). Patients carrying the R302Q mutation in PRKAG2 present sinus bradycardia, escape rhythms, ventricular pre-excitation, supraventricular tachycardia and atrioventricular block. This mutation affects AMPK activity and increases glycogen storage in cardiomyocytes. The link between glycogen storage, WPW, HCM and arrhythmias remains unknown. OBJECTIVE: To investigate the pathological changes caused by the PRKAG2 mutation we tested the hypothesis that the patient's induced Pluripotent Stem Cell-derived cardiomyocytes (iPSC-CMs) display clinical aspects of the disease. METHODS: Using the CRISPR technology we corrected the mutation and generated isogenic iPSC-CMs. Action potentials were recorded from spontaneously firing and paced cardiomyocytes using the patch clamp technique. Using the Micro Electrode Array (MEA) set up we recorded electrograms from iPSC-CMs clusters. Transmission Electron Microscopy (TEM) was used to detect ultrastructural abnormalities in the mutated iPSC-CMs. RESULTS: PRKAG2-mutated iPSC-CMs exhibited abnormal firing patterns, delayed afterdepolarizations (DADs), triggered arrhythmias and augmented Beat Rate Variability (BRV). Importantly, the CRISPR correction eliminated the electrophysiological abnormalities, the augmented glycogen storage and cardiomyocyte hypertrophy. CONCLUSION: PRKAG2-mutated iPSC-CMs displayed functional and structural abnormalities, which were abolished by correcting the mutation in the patient's iPSCs using the CRISPR technology