MicroRNA-133 modulates the b1-adrenergic receptor transduction cascade

RATIONALE:: The sympathetic nervous system plays a fundamental role in the regulation of myocardial function. During chronic pressure overload, overactivation of the sympathetic nervous system induces the release of catecholamines, which activate ?-adrenergic receptors in cardiomyocytes and lead to increased heart rate and cardiac contractility. However, chronic stimulation of ?-adrenergic receptors leads to impaired cardiac function, and ?-blockers are widely used as therapeutic agents for the treatment of cardiac disease. MicroRNA-133 (miR-133) is highly expressed in the myocardium and is involved in controlling cardiac function through regulation of messenger RNA translation/stability. OBJECTIVE:: To determine whether miR-133 affects ?-adrenergic receptor signaling during progression to heart failure. METHODS AND RESULTS:: Based on bioinformatic analysis, ?1-adrenergic receptor (?1AR) and other components of the ?1AR signal transduction cascade, including adenylate cyclase VI and the catalytic subunit of the cAMP-dependent protein kinase A, were predicted as direct targets of miR-133 and subsequently validated by experimental studies. Consistently, cAMP accumulation and activation of downstream targets were repressed by miR-133 overexpression in both neonatal and adult cardiomyocytes following selective ?1AR stimulation. Furthermore, gain-of-function and loss-of-function studies of miR-133 revealed its role in counteracting the deleterious apoptotic effects caused by chronic ?1AR stimulation. This was confirmed in vivo using a novel cardiac-specific TetON-miR-133 inducible transgenic mouse model. When subjected to transaortic constriction, TetON-miR-133 inducible transgenic mice maintained cardiac performance and showed attenuated apoptosis and reduced fibrosis compared with control mice. CONCLUSIONS:: miR-133 controls multiple components of the ?1AR transduction cascade and is cardioprotective during heart failure. © 2014 American Heart Association, Inc.