Evaluation of desmosome dynamics using iPS cell-derived cardiomyocytes identifies neddylation inhibitor as a modifier of relaxation in arrhythmogenic cardiomyopathy

Background Arrhythmogenic cardiomyopathy (ACM) is a hereditary disease caused by desmosomal haploinsufficiency and associated with heart failure and sudden cardiac death. Disease-modifying therapies targeting the underlying molecular mechanisms remain limited. Isogenic-induced pluripotent stem cell–derived cardiomyocytes (iPSC-CMs) have previously been generated from a patient with ACM carrying a heterozygous plakophilin-2 ( PKP2 ) pathogenic variant expressing fluorescently tagged desmoglein-2 (DSG2) for real-time desmosome imaging. This study aimed to establish a quantitative platform to evaluate desmosome dynamics and identify potential therapeutic candidates for ACM treatment. Methods In this study, an artificial intelligence (AI)-based evaluation system was established, followed by a quantitative analysis, to identify a candidate compound that restores desmosomes. The functional effects were assessed using motion vector analysis. RNA sequencing combined with linear regression and gene set enrichment analyses was performed to investigate the molecular mechanisms. Three-dimensionally structured iPSC-CMs aligned using a nanofiber device were used to evaluate collagen deposition. Results Fluorescently labeled isogenic iPSC-CMs recapitulated desmosome dynamics, and the established AI algorithm distinguished desmosome images according to their genotypes. AI evaluation, followed by quantitative analysis of desmosome dynamics, identified pevonedistat, a specific neddylation inhibitor that restored the DSG2 area and distribution at concentrations below 50 nM. Motion vector analysis revealed that high-dose pevonedistat exhibited toxicity and reduced contractility, whereas low-dose pevonedistat (50 nM) significantly improved relaxation without affecting the contractility of iPSC-CMs. Transcriptomic analyses revealed a dose-dependent suppression of collagen-related genes and activation of nuclear factor erythroid 2–related factor 2 ( NRF2 )-regulated pathways. Consistently, pevonedistat treatment significantly suppressed collagen deposition in the structured iPSC-CMs. Conclusions These findings demonstrate that the quantitative evaluation of desmosome dynamics enables the identification of therapeutic candidates for ACM. The inhibition of neddylation by pevonedistat improves cardiomyocyte relaxation, potentially by restoring desmosome integrity, suppressing fibrosis, and activating the NRF2 signaling pathway.