Cardiac pressure overload hypertrophy is differentially regulated by β-adrenergic receptor subtypes

Am J Physiol Heart Circ Physiol. 2011 Oct;301(4):H1461-70. doi: 10.1152/ajpheart.00453.2010. Epub 2011 Jun 24.

Abstract

In isolated myocytes, hypertrophy induced by norepinephrine is mediated via α(1)-adrenergic receptors (ARs) and not β-ARs. However, mice with deletions of both major cardiac α(1)-ARs still develop hypertrophy in response to pressure overload. Our purpose was to better define the role of β-AR subtypes in regulating cardiac hypertrophy in vivo, important given the widespread clinical use of β-AR antagonists and the likelihood that patients treated with these agents could develop conditions of further afterload stress. Mice with deletions of β(1), β(2), or both β(1)- and β(2)-ARs were subjected to transverse aortic constriction (TAC). After 3 wk, β(1)(-/-) showed a 21% increase in heart to body weight vs. sham controls, similar to wild type, whereas β(2)(-/-) developed exaggerated (49% increase) hypertrophy. Only when both β-ARs were ablated (β(1)β(2)(-/-)) was hypertrophy totally abolished. Cardiac function was preserved in all genotypes. Several known inhibitors of cardiac hypertrophy (FK506 binding protein 5, thioredoxin interacting protein, and S100A9) were upregulated in β(1)β(2)(-/-) compared with the other genotypes, whereas transforming growth factor-β(2), a positive mediator of hypertrophy was upregulated in all genotypes except the β(1)β(2)(-/-). In contrast to recent reports suggesting that angiogenesis plays a critical role in regulating cardiac hypertrophy-induced heart failure, we found no evidence that angiogenesis or its regulators (VEGF, Hif1α, and p53) play a role in compensated cardiac hypertrophy. Pressure overload hypertrophy in vivo is dependent on a coordination of signaling through both β(1)- and β(2)-ARs, mediated through several key cardiac remodeling pathways. Angiogenesis is not a prerequisite for compensated cardiac hypertrophy.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Angiogenesis Inducing Agents / metabolism
  • Animals
  • Aorta, Thoracic / physiology
  • Blood Pressure / physiology
  • Cardiomegaly / etiology
  • Cardiomegaly / genetics
  • Cardiomegaly / physiopathology*
  • Constriction, Pathologic / physiopathology
  • Electrocardiography
  • Genome-Wide Association Study
  • Heart / physiopathology*
  • Heart Failure / etiology
  • Heart Failure / physiopathology
  • Hypertension / complications
  • Hypertension / genetics
  • Hypertension / physiopathology*
  • Male
  • Mice
  • Mice, Knockout
  • Microarray Analysis
  • Paraffin Embedding
  • RNA / biosynthesis
  • RNA / genetics
  • Receptors, Adrenergic, beta / genetics
  • Receptors, Adrenergic, beta / physiology*
  • Receptors, Adrenergic, beta-1 / genetics
  • Receptors, Adrenergic, beta-1 / physiology
  • Receptors, Adrenergic, beta-2 / genetics
  • Receptors, Adrenergic, beta-2 / physiology
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / genetics
  • Signal Transduction / physiology

Substances

  • Angiogenesis Inducing Agents
  • Receptors, Adrenergic, beta
  • Receptors, Adrenergic, beta-1
  • Receptors, Adrenergic, beta-2
  • RNA