Desmosome imaging using iPS cell-derived cardiomyocytes identifies neddylation inhibitor as a modifier of relaxation in arrhythmogenic cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM), caused by plakophilin-2 (PKP2) haploinsufficiency, disrupts desmosomal integrity and extracellular matrix organization, causing ventricular dysfunction and sudden cardiac death in young individuals. Despite mechanistic advances, current management remains supportive. No therapy directly targets desmosomal pathology, partly due to the lack of human models enabling real-time quantitative assessment of desmosomes. To overcome this limitation, we developed an iPSC-derived cardiomyocyte platform with a desmoglein-2 (DSG2)–tdTomato live-cell reporter. It visualizes endogenous desmosomes in real time and is integrated with AI-based analysis for structure-informed compound screening.

To identify compounds that restore desmosome organization in PKP2-deficient cardiomyocytes and to elucidate their underlying mechanisms.

Isogenic PKP2-edited iPSC lines carrying a DSG2-tdTomato reporter were generated by CRISPR–Cas9 and differentiated into cardiomyocytes. Desmosomal morphology was quantified using an AI-assisted imaging pipeline. Contractile function was evaluated by motion vector–based analysis. Mechanistic studies included RNA sequencing, immunofluorescence of collagen deposition in 3D engineered nanofiber tissues, and Western blotting of NRF2(Nuclear factor erythroid 2–related factor 2)-related proteins.

The PKP2-edited iPSC model showed genotype-dependent reductions in plakophilin-2 and corresponding defects in desmosome organization, which were accurately classified by the AI model. Using this platform, pevonedistat, a neddylation inhibitor, was identified as the most effective compound for restoring desmosome architecture. Motion analysis demonstrated that pevonedistat improved cardiomyocyte relaxation function without inducing cytotoxicity. Transcriptomic profiling showed a dose-dependent response marked by activation of the antioxidant regulator nuclear factor erythroid 2–related factor 2 (NRF2) and suppression of collagen synthesis. Consistently, pevonedistat increased NRF2 and its downstream effector NAD(P)H quinone dehydrogenase 1 (NQO1) while reducing COL1 abundance in 2D cultures, and also attenuated collagen deposition in 3D aligned tissues, preserving myocardial organization in a more physiologically relevant context.

Taken together, our iPSC–AI platform shows that pevonedistat stabilizes desmosomes and improves relaxation through NRF2 activation and reduced collagen biosynthesis. These findings reveal a regulatory link between neddylation and desmosome integrity and support neddylation inhibition as a potential disease-modifying therapy for PKP2-related arrhythmogenic cardiomyopathy.For image description, please refer to the figure legend and surrounding text.  For image description, please refer to the figure legend and surrounding text.