A zebrafish stable model of Galectin-3 to elucidate its role in arrhythmogenic cardiomyopathy.

Galectin-3 (Gal-3) dysregulation has emerged as a critical mediator of inflammatory processes in arrhythmogenic cardiomyopathy (AC), playing pivotal roles in modulating Wnt/β-catenin signaling and regulating macrophage polarization. AC is a rare genetic disorder, primarily driven by desmosomal gene variants, characterized by fibro-fatty replacement of the ventricular myocardium, progressive ventricular dysfunction, and heightened arrhythmic risk in the young and athletes. To investigate the role of this multifaceted lectin in AC pathogenesis, we developed and characterized a stable lgals3a (-aa) knock-out zebrafish model. lgals3a deficiency recapitulated several AC-like pathological features, including ventricular adipose infiltration, chamber dilation, pericardial effusion, and rhythm abnormalities from larval to adult stages. Ultrastructural analyses revealed disrupted desmosomes, directly implicating Gal-3 in intercellular adhesion independent of other desmosomal gene variants. Transcriptomic analyses demonstrated suppression of both Wnt/β-catenin and TGFβ signaling. Early-stage pharmacological activation of Wnt signaling partially rescued cardiac function, whereas structural defects persisted in adults, indicating that therapeutic efficacy is strongly dependent on disease stage and timing of intervention. Inflammatory profiling revealed significant immune cell infiltration and upregulation of macrophage-related proinflammatory genes (i.e., mmp25b and il12rb2), consistent with AC "hot phases". This study revealed lgals3a deficiency as a contributor to AC-like pathological features in zebrafish and supports a role for Gal-3 in maintaining cardiac intercellular adhesion, inflammatory homeostasis, and cardiac function.