The ADP-ribosyltransferases 3 (ART3) is a novel suppressor of pathological cardiac hypertrophy by ribosylating ITGA7.

Pathological cardiac hypertrophy and heart failure remain mechanistically incompletely defined despite their clinical significance in cardiovascular disease. While ADP-ribosyltransferase cholera toxin-like (ARTC) enzymes modulate membrane protein function and downstream signaling via post-translational modifications, their role in cardiac pathology remains unexplored. Herein, we investigated the regulatory involvement of ADP-ribosyltransferase 3 (ART3) in myocardial remodeling. Cardiomyocyte-specific ART3 knockdown and overexpression murine models were established using adeno-associated virus serotype 9 (AAV9), with RNA-sequencing employed to profile ART3-dependent transcriptional responses in pathological cardiac hypertrophy. Functional validation was performed in complementary in vitro and in vivo hypertrophy models, complemented by immunoprecipitation-coupled mass spectrometry to identify ART3 substrates. ART3 was found to be cardiomyocyte-enriched and transcriptionally downregulated during progressive myocardial remodeling and heart failure. Cardiomyocyte-specific ART3 knockdown 3 accelerated the decompensatory transition of cardiac hypertrophy, whereas ART3 overexpression exerted significant anti-hypertrophic and anti-remodeling effects. Mechanistically, ART3 preserved cardiomyocyte mono-ADP-ribosyltransferase activity, catalyzing the site-specific mono-ADP-ribosylation (mADPr) of Integrin Subunit Alpha 7 (ITGA7) at residue R129. This post-translational modification was requisite for integrin signaling pathway activation, which mediated the observed cardioprotective effects. Collectively, these findings establish ART3 as a novel regulator of pathological cardiac hypertrophy by modulating ITGA7 via mADPr, highlighting its therapeutic potential as a target for heart failure intervention.