Background: Arrhythmogenic cardiomyopathy (AC) is a myocardial disease due to desmosomal mutations whose pathogenesis is incompletely understood.
Objective: The purpose of this study was to identify molecular pathways underlying early AC by gene expression profiling in both humans and animal models.
Methods: RNA sequencing for differentially expressed genes (DEGs) was performed on the myocardium of transgenic mice overexpressing the Desmoglein2-N271S mutation before phenotype onset. Zebrafish signaling reporters were used for in vivo validation. Whole exome sequencing was undertaken in 10 genotype-negative AC patients and subsequent direct sequencing in 140 AC index cases.
Results: Among 29 DEGs identified at early disease stages, Lgals3/GAL3 (lectin, galactoside-binding, soluble, 3) showed reduced cardiac expression in transgenic mice and in 3 AC patients who suffered sudden cardiac death without overt structural remodeling. Four rare missense variants of LGALS3 were identified in 5 human AC probands. Pharmacologic inhibition of Lgals3 in zebrafish reduced Wnt and transforming growth factor-β signaling, increased Hippo/YAP-TAZ signaling, and induced alterations in desmoplakin membrane localization, desmosome integrity and stability. Increased LGALS3 plasma expression in genotype-positive AC patients and CD98 activation supported the galectin-3 (GAL3) release by circulating macrophages pointing toward the stabilization of desmosomal assembly at the injured regions.
Conclusion: GAL3 plays a crucial role in early AC onset through regulation of Wnt/β-catenin signaling and intercellular adhesion.
Keywords: Arrhythmogenic cardiomyopathy; Gene expression; Inflammation; LGALS3; Transgenic models; Wnt signaling.
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