PRKAG2-mutations cause bioenergetic and metabolic aberrations in iPSC-CMs generated from a WPW patient and in transgenic mice
2The Rappaport Institute, Technion - Israel Institute of Technology, Israel
3Technion Integrated Cancer Center, Technion - Israel Institute of Technology, Israel
4Division of Cardiovascular Medicine, Department of Internal Medicine, Carver College of Medicine, University of Iowa, USA
5Leviev Heart Center, Sheba Medical Center, Israel
6Sackler Faculty of Medicine, Tel Aviv University, Israel
Introduction
Familial hypertrophic cardiomyopathy (HCM) is caused by over 400 sarcomeric and non-sarcomeric mutations, such as PRKAG2, involved in bioenergetic and metabolic pathways. PRKAG2 mutations can lead to autosomal dominant ventricular pre-excitation - Wolff-Parkinson-White syndrome (WPW), and a progressive conduction system disease.
Methods
Mutated and isogenic induced Pluripotent Stem Cell-derived cardiomyocytes (iPSC-CMs) were generated from a WPW patient carrying the R302Q mutation and control iPSC-CMs from healthy volunteers. Bioenergetic (Oxygen Consumption Rate, OCR) and metabolic status were measured using Seahorse Flux Analyzer and LC-MS, respectively. Additionally, we analyzed the metabolic profile of hearts from WT mice and transgenic mice carrying the PRKAG2 T400N mutation (TGT400N). To decipher the molecular basis underlying the bioenergetic and metabolic deficits, RNA-seq analysis was performed.
Results
The OCR results demonstrated in PRKAG2-mutated compared to isogenic and healthy iPSC-CMs, a 2-fold increase in non-mitochondrial oxygen consumption and maximal respiration rate, while basal OCR parameters were similar in all groups. Importantly, when treated with the AMPK activator metformin (2.5 mM), the abovementioned OCR parameters were similar in the three groups. RNA-seq analysis demonstrated that of the 99 mutually differentially expressed genes (DEGs), compared to isogenic and healthy cells, the most relevant altered pathways were glycolysis, carbon metabolism, biosynthesis of amino acids, HIF-1 signaling and fructose and mannose metabolism. These findings are consistent with the LC-MS results from iPSC-CMs and mice hearts, demonstrating in PRKAG2-mutated versus controls significant changes in metabolites linked to the abovementioned pathways levels.
Conclusions
in agreement with in-vivo model, PRKAG2-mutated iPSC-CMs exhibit bioenergetic and metabolic aberrations, contributing to the cardiac pathological aspects of WPW syndrome. Importantly, treatment with the AMPK activator metformin eliminated the bioenergetic deficits in mutated cardiomyocytes, while isogenic and healthy control cells remained unaffected. Based on these novel findings, a new therapeutic modality in WPW patients may be considered.
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