Abstract
BACKGROUND: Chronic stimulation of the beta(1)-adrenoceptor (beta(1)AR)
plays a crucial role in the pathogenesis of heart failure; however,
underlying mechanisms remain to be elucidated. The regulation by
transcription factors cAMP response element-binding protein (CREB)
and cyclic AMP response element modulator (CREM) represents a fundamental
mechanism of cyclic AMP-dependent gene control possibly implicated
in beta(1)AR-mediated cardiac deterioration. METHODS AND RESULTS:
We studied the role of CREM in beta(1)AR-mediated cardiac effects,
comparing transgenic mice with heart-directed expression of beta(1)AR
in the absence and presence of functional CREM. CREM inactivation
protected from cardiomyocyte hypertrophy, fibrosis, and left ventricular
dysfunction in beta(1)AR-overexpressing mice. Transcriptome and proteome
analysis revealed a set of predicted CREB/CREM target genes including
the cardiac ryanodine receptor, tropomyosin 1alpha, and cardiac alpha-actin
as altered on the mRNA or protein level along with the improved phenotype
in CREM-deficient beta(1)AR-transgenic hearts. CONCLUSIONS: The results
imply the regulation of genes by CREM as an important mechanism of
beta(1)AR-induced cardiac damage in mice.
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