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Abstract
Physiological cardiac hypertrophy occurs in response to exercise and can protect against pathological stress. In contrast, pathological hypertrophy occurs in disease and often precedes heart failure. The cardiac pathways activated in physiological and pathological hypertrophy are largely distinct. Our prior work demonstrated that miR-222 increases in exercised hearts and is required for exercise-induced cardiac hypertrophy and cardiomyogenesis. Here, we sought to define the role of miR-222 in pathological hypertrophy.We found that miR-222 also increased in pathological hypertrophy induced by pressure overload. To assess its functional significance in this setting, we generated a miR-222 gain-of-function model through cardiac-specific constitutive transgenic miR-222 expression (TgC-miR-222) and used locked nucleic acid (LNA) anti-miR specific for miR-222 to inhibit its effects. Both gain- and loss-of-function models manifested normal cardiac structure and function at baseline. However, after transverse aortic constriction (TAC), miR-222 inhibition accelerated the development of pathological hypertrophy, cardiac dysfunction, and heart failure. Conversely, miR-222-overexpressing mice had less pathological hypertrophy after TAC, as well as better cardiac function and survival. We identified PUMA, a pro-apoptotic Bcl-2 family member, and the transcription factors, Hmbox1 and NFATc3, as direct miR-222 targets contributing to its roles in this context.While miR-222 is necessary for physiological cardiac growth, it inhibits cardiac growth in response to pressure overload and reduces adverse remodeling and cardiac dysfunction. These findings support the model that physiological and pathological hypertrophy are fundamentally different. Further, they suggest miR-222 may hold promise as a therapeutic target in pathological cardiac hypertrophy and heart failure.We report that miR-222 was necessary and sufficient to limit cardiac growth, cardiomyocyte cell death, adverse ventricular remodeling, and cardiac dysfunction in response to pressure overload. This suggests possible therapeutic value, particularly as miR-222 is conserved between mice and humans and regulated by exercise in both.
View details for DOI 10.1093/cvr/cvad184
View details for PubMedID 38084908