NEDD4-Mediated GSNOR Degradation Aggravates Cardiac Hypertrophy and Dysfunction.

Background: The decrease in S-nitrosoglutathione reductase (GSNOR) leads to an elevation of S-nitrosylation, thereby exacerbating the progression of cardiomyopathy in response to hemodynamic stress. However, the mechanisms under GSNOR decrease remain unclear. Here, we identify NEDD4 (neuronal precursor cell expressed developmentally downregulated 4) as a novel molecule that plays a crucial role in the pathogenesis of pressure overload-induced cardiac hypertrophy, by modulating GSNOR levels, thereby demonstrating significant therapeutic potential.

Methods: Protein synthesis and degradation inhibitors were used to verify the reasons for the decrease in GSNOR. Mass spectrometry and database filtering were used to uncover NEDD4, the E3 Ub (ubiquitin) ligase, involved in GSNOR decrease. NEDD4 cardiomyocyte-specific deficiency mice were used to evaluate the role of NEDD4 and NEDD4-induced ubiquitination of GSNOR in cardiac hypertrophy in vivo. Both IBM, a highly specific NEDD4 inhibitor, and indole-3-carbinol, a NEDD4 inhibitor currently undergoing phase 2 clinical trial, were used to effectively suppress the NEDD4/GSNOR axis.

Results: GSNOR protein levels were reduced, while mRNA levels remained unchanged in myocardium samples from hypertrophic patients and transverse aortic constriction-induced mice, indicating GSNOR is regulated by ubiquitination. NEDD4, an E3 Ub ligase, was associated with GSNOR ubiquitination, which exhibited significantly higher expression levels in hypertrophic myocardial samples. Moreover, either the NEDD4 enzyme-dead mutant or GSNOR nonubiquitylated mutant decreased GSNOR ubiquitination and inhibited cardiac hypertrophic growth. Cardiomyocyte-specific NEDD4 deficiency inhibited cardiac hypertrophy in vitro and in vivo. NEDD4 inhibitor IBM effectively suppressed GSNOR ubiquitination and cardiac hypertrophy. Clinically, indole-3-carbinol, a NEDD4 inhibitor in phase II clinical trials used as an antitumor drug, demonstrated comparable efficacy.

Conclusions: Our findings showed that upregulated NEDD4 leads to GSNOR ubiquitination and subsequent degradation, thereby facilitating the progression of cardiac hypertrophy. NEDD4 inhibitors may serve as a potential therapeutic strategy for the treatment of cardiac hypertrophy and heart failure.