MCP-1/CCL2 protects cardiac myocytes from hypoxia-induced apoptosis by a G(alphai)-independent pathway

Biochem Biophys Res Commun. 2005 Oct 7;335(4):1008-16. doi: 10.1016/j.bbrc.2005.07.168.

Abstract

Chemokines, in addition to their chemotactic properties, act upon resident cells within a tissue and mediate other cellular functions. In a previous study, we demonstrated that CCL2 protects cultured mouse neonatal cardiac myocytes from hypoxia-induced cell death. Leukocyte chemotaxis has been shown to contribute to ischemic injury. While the chemoattractant properties of CCL2 have been established, the protective effects of this chemokine suggest a novel role for CCL2 in myocardial ischemia/reperfusion injury. The present study examined the cellular signaling pathways that promote this protection. Treatment of cardiac myocyte cultures with CCL2 protected them from hypoxia-induced apoptosis. This protection was not mediated through the activation of G(alphai) signaling that mediates monocyte chemotaxis. Inhibition of the ERK1/2 signaling pathway abrogated CCL2 protection. Caspase 3 activation and JNK/SAPK phosphorylation were decreased in hypoxic myocytes co-treated with CCL2 as compared to hypoxia only-treated cultures. Expression of the Bcl-2 family proteins, Bcl-xL and Bag-1, was increased in CCL2-treated myocytes subjected to hypoxia. There was also downregulation of Bax protein levels as a result of CCL2 co-treatment. These data suggest that CCL2 cytoprotection and chemotaxis may occur through distinct signaling mechanisms.

Publication types

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

MeSH terms

  • Animals
  • Animals, Newborn
  • Apoptosis / drug effects
  • Apoptosis / physiology*
  • Cardiotonic Agents / administration & dosage
  • Cell Hypoxia / drug effects
  • Cell Hypoxia / physiology*
  • Cells, Cultured
  • Chemokine CCL2 / administration & dosage*
  • Cytokines / metabolism*
  • Dose-Response Relationship, Drug
  • GTP-Binding Protein alpha Subunits, Gi-Go / metabolism*
  • Myocytes, Cardiac / drug effects
  • Myocytes, Cardiac / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction / drug effects
  • Signal Transduction / physiology*

Substances

  • Cardiotonic Agents
  • Ccl2 protein, rat
  • Chemokine CCL2
  • Cytokines
  • GTP-Binding Protein alpha Subunits, Gi-Go