The activin receptor ligand trap ActRIIB:ALK4-Fc ameliorates cardiomyopathy induced by neuromuscular disease and diabetes.

Cardiomyopathies are ascribed to a variety of etiologies, present with diverse clinical phenotypes, and lack disease-modifying treatments. Mounting evidence implicates dysregulated activin receptor signaling in heart disease and highlights inhibition of this pathway as a potential therapeutic target. Here, we explored the effects of activin ligand inhibition using ActRIIB:ALK4-Fc, a heterodimeric receptor fusion protein, in two mechanistically distinct murine models of cardiomyopathy. Treatment with ActRIIB:ALK4-Fc significantly improved systolic or diastolic function in cardiomyopathy induced by neuromuscular disease or diabetes mellitus. Moreover, ActRIIB:ALK4-Fc corrected Ca2+ handling protein expression in diseased heart tissues, suggesting that activin signaling inhibition could alleviate cardiomyopathies in part by rebalancing aberrant intracellular Ca2+ homeostasis-a common underlying pathomechanism in diverse heart diseases.