Differential regulation of p90 ribosomal S6 kinase and big mitogen- activated protein kinase 1 by ischemia/reperfusion and oxidative stress in perfused guinea pig hearts

Yasuchika Takeishi, Jun Ichi Abe, Jiing Dwan Lee, Hisaaki Kawakatsu, Richard A. Walsh, Bradford C. Berk

Research output: Contribution to journalArticlepeer-review

83 Scopus citations

Abstract

Reactive oxygen species (ROS) activate members of the Src kinase and mitogen-activated protein kinase superfamily, including big mitogen-activated protein kinase 1 (BMK1) and extracellular signal-regulated kinases (ERK1/2). A potentially important downstream effector of ERK1/2 is p90 ribosomal S6 kinase (p90RSK), which plays an important role in cell growth through the activation of several transcription factors, as well as the Na+/H+ exchanger. Previously, we showed that Src regulates BMK1 via a redox- sensitive signaling pathway. Because ROS are generated during ischemia and reperfusion after ischemia, we assessed the effects of these stimuli (H2O2, ischemia, and reperfusion) in the activation of ERK1/2, p90RSK, Src, and BMK1 in perfused guinea pig hearts. H2O2 (100 μmol/L) significantly activated all kinases. Ischemia alone stimulated p90RSK, Src, and BMK1 but not ERK1/2. These results suggest that p90RSK activation through ischemia occurs via a pathway other than ERK1/2. A role of Src in ischemia-mediated BMK1 activation was demonstrated through inhibition with the Src inhibitor 4-amino-5-(4- chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine. Reperfusion after ischemia stimulated both p90RSK and ERK1/2. In contrast, although ROS increase during reperfusion after ischemia, the activities of both BMK1 and its upstream regulator, Src, were markedly attenuated by reperfusion after ischemia. The activation of C-terminal Src kinase during ischemia but not during reperfusion suggests that the attenuation of Src and BMK1 activity by reperfusion was not regulated by C-terminal Src kinase activity. The antioxidant N-2-mercaptopropionylglycine completely inhibited ERK1/2 and p90RSK activation by reperfusion but only partially inhibited ischemia- induced Src and BMK1 activation. The present study is the first to show the coregulation of Src and BMK1 by reperfusion after ischemia, which we propose to occur via a novel, ROS-independent pathway.

Original languageEnglish (US)
Pages (from-to)1164-1172
Number of pages9
JournalCirculation research
Volume85
Issue number12
DOIs
StatePublished - Dec 3 1999
Externally publishedYes

Keywords

  • Ischemia
  • Myocardium
  • Oxidative stress
  • Transduction

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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