beta1 integrins expression in adult rat ventricular myocytes and its role in the regulation of beta-adrenergic receptor-stimulated apoptosis

J Cell Biochem. 2003 May 15;89(2):381-8. doi: 10.1002/jcb.10520.

Abstract

We have shown that the stimulation of beta-adrenergic receptors (beta-AR) increases apoptosis in adult rat ventricular myocytes (ARVMs). Integrins, a family of alphabeta-heterodimeric cell surface receptors, are postulated to play a role in ventricular remodeling. Here, we show that norepinephrine (NE) increases beta1 integrins expression in ARVMs via the stimulation of alpha1-AR, not beta-AR. Inhibition of ERK1/2 using PD 98059, an inhibitor of ERK1/2 pathway, inhibited alpha1-AR-stimulated increases in beta1 integrins expression. Activation of beta1 integrins signaling pathway using laminin (LN) inhibited beta-AR-stimulated apoptosis as measured by terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL)-staining and flow cytometry. Likewise, ligation of beta1 integrins with anti-beta1 integrin antibodies prevented beta-AR-stimulated apoptosis. Treatment of cells using LN or anti-beta1 integrin antibodies activated ERK1/2 pathway. PD 98059 inhibited activation of ERK1/2 by LN, and prevented the anti-apoptotic effects of LN. Thus (1) stimulation of alpha1-AR regulates beta1 integrins expression via the activation of ERK1/2, (2) beta1 integrins signaling protects ARVMs from beta-AR-stimulated apoptosis, (3) activation of ERK1/2 plays a critical role in the anti-apoptotic effects of beta1-integrin signaling. These data suggest that beta1 integrin signaling protects ARVMs against beta-AR-stimulated apoptosis possibly via the involvement of ERK1/2.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apoptosis / physiology*
  • Enzyme Activation
  • Heart Ventricles / metabolism*
  • Integrin beta1 / metabolism*
  • Male
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinases / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Adrenergic, beta / physiology*
  • Signal Transduction

Substances

  • Integrin beta1
  • Receptors, Adrenergic, beta
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinases