Transforming growth factor β₁ oppositely regulates the hypertrophic and contractile response to β-adrenergic stimulation in the heart

PLoS One. 2011;6(11):e26628. doi: 10.1371/journal.pone.0026628. Epub 2011 Nov 17.


Background: Neuroendocrine activation and local mediators such as transforming growth factor-β₁ (TGF-β₁) contribute to the pathobiology of cardiac hypertrophy and failure, but the underlying mechanisms are incompletely understood. We aimed to characterize the functional network involving TGF-β₁, the renin-angiotensin system, and the β-adrenergic system in the heart.

Methods: Transgenic mice overexpressing TGF-β₁ (TGF-β₁-Tg) were treated with a β-blocker, an AT₁-receptor antagonist, or a TGF-β-antagonist (sTGFβR-Fc), were morphologically characterized. Contractile function was assessed by dobutamine stress echocardiography in vivo and isolated myocytes in vitro. Functional alterations were related to regulators of cardiac energy metabolism.

Results: Compared to wild-type controls, TGF-β₁-Tg mice displayed an increased heart-to-body-weight ratio involving both fibrosis and myocyte hypertrophy. TGF-β₁ overexpression increased the hypertrophic responsiveness to β-adrenergic stimulation. In contrast, the inotropic response to β-adrenergic stimulation was diminished in TGF-β₁-Tg mice, albeit unchanged basal contractility. Treatment with sTGF-βR-Fc completely prevented the cardiac phenotype in transgenic mice. Chronic β-blocker treatment also prevented hypertrophy and ANF induction by isoprenaline, and restored the inotropic response to β-adrenergic stimulation without affecting TGF-β₁ levels, whereas AT₁-receptor blockade had no effect. The impaired contractile reserve in TGF-β₁-Tg mice was accompanied by an upregulation of mitochondrial uncoupling proteins (UCPs) which was reversed by β-adrenoceptor blockade. UCP-inhibition restored the contractile response to β-adrenoceptor stimulation in vitro and in vivo. Finally, cardiac TGF-β₁ and UCP expression were elevated in heart failure in humans, and UCP--but not TGF-β₁--was downregulated by β-blocker treatment.

Conclusions: Our data support the concept that TGF-β₁ acts downstream of angiotensin II in cardiomyocytes, and furthermore, highlight the critical role of the β-adrenergic system in TGF-β₁-induced cardiac phenotype. Our data indicate for the first time, that TGF-β₁ directly influences mitochondrial energy metabolism by regulating UCP3 expression. β-blockers may act beneficially by normalizing regulatory mechanisms of cellular hypertrophy and energy metabolism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic beta-1 Receptor Antagonists / pharmacology
  • Adrenergic beta-Agonists / pharmacology*
  • Adrenergic beta-Antagonists / pharmacology*
  • Angiotensin II Type 1 Receptor Blockers / pharmacology
  • Animals
  • Benzimidazoles / pharmacology
  • Benzoates / pharmacology
  • Cardiomegaly / diagnostic imaging
  • Cardiomegaly / genetics
  • Cardiomegaly / metabolism*
  • Cells, Cultured
  • Echocardiography, Stress
  • Gene Expression Regulation / drug effects
  • Heart / drug effects*
  • Heart / physiology
  • Humans
  • Ion Channels / genetics
  • Isoproterenol / pharmacology
  • Metoprolol / pharmacology
  • Mice
  • Mice, Transgenic
  • Mitochondrial Proteins / genetics
  • Myocardial Contraction / drug effects*
  • Myocardium / metabolism
  • Myocytes, Cardiac / drug effects
  • Myocytes, Cardiac / metabolism
  • Myocytes, Cardiac / physiology
  • Reverse Transcriptase Polymerase Chain Reaction
  • Telmisartan
  • Transforming Growth Factor beta1 / genetics
  • Transforming Growth Factor beta1 / metabolism*
  • Uncoupling Protein 3


  • Adrenergic beta-1 Receptor Antagonists
  • Adrenergic beta-Agonists
  • Adrenergic beta-Antagonists
  • Angiotensin II Type 1 Receptor Blockers
  • Benzimidazoles
  • Benzoates
  • Ion Channels
  • Mitochondrial Proteins
  • Transforming Growth Factor beta1
  • UCP3 protein, human
  • Ucp3 protein, mouse
  • Uncoupling Protein 3
  • Metoprolol
  • Isoproterenol
  • Telmisartan