Modelling arrhythmogenic cardiomyopathy fattyfibro pathology with PKP2-deficient epicardial cells derived from human iPSCs.

Arrhythmogenic cardiomyopathy (ACM) is an inherited heart disease marked by progressive fattyfibro replacement of the ventricular myocardium, life-threatening arrhythmias, and sudden cardiac death. To dissect epicardial contributions to ACM pathogenesis, we generated iPSC lines from patients carrying plakophilin 2 (PKP2) 1849C > T or PKP2 2013delC mutations, their CRISPR/Cas9-corrected isogenic controls, and a PKP2 knockout line. Epicardial cells (hPSC-EPCs) differentiated from mutant and knockout backgrounds exhibit enhanced epithelial-to-mesenchymal transition characteristics, increased lipid accumulation, and a pronounced fibrotic phenotype. RNA-seq performed on ACM hPSC-EPCs reveals dysregulation of Wnt, interferon, and Rho GTPase signaling, including an upregulation of insulin growth factor 2 (IGF2) and a key adipogenic transcription factor, CEBPA. Subsequent treatment of control and PKP2KO hPSC-EPCs with recombinant IGF2 enhances CEBPA expression, suggesting that insulin growth factor signaling contributes to ACM fattyfibro remodeling.