Activation of Rho/Rho kinase signaling pathway by reactive oxygen species in rat aorta

Liming Jin, Zhekang Ying, R. Clinton Webb

Research output: Contribution to journalArticle

192 Scopus citations

Abstract

Evidence indicates that both the Rho/Rho kinase signaling pathway and reactive oxygen species (ROS) such as superoxide and H2O2 are involved in the pathogenesis of hypertension. This study aimed to determine whether ROS-induced vascular contraction is mediated through activation of Rho/Rho kinase. Rat aortic rings (endothelium denuded) were isolated and placed in organ chambers for measurement of isometric force development. ROS were generated by a xanthine (X)-xanthine oxidase (XO) mixture. The antioxidants tempol (3 mM) and catalase (1,200 U/ml) or the XO inhibitor allopurinol (400 μ) significantly reduced X/XO-induced contraction. A Rho kinase inhibitor, (+)-(R)-trans-4-(1-aminoethyl-N-4-pyridil)cyclohexanecarboxamide dihydrochloride (Y-27632), decreased the contraction in a concentration-dependent manner; however, the Ca2+-independent protein kinase C inhibitor rottlerin did not have an effect on X/XO-induced contraction. Phosphorylation of the myosin light chain phosphatase target subunit (MYPT1) was increased by ROS, and preincubation with Y-27632 blocked this increased phosphorylation. Western blotting for cytosolic and membrane-bound fractions of Rho showed that Rho was increased in the membrane fraction by ROS, suggesting activation of Rho. These observations demonstrate that ROS-induced Ca2+ sensitization is through activation of Rho and a subsequent increase in Rho kinase activity but not Ca2+-independent PKC.

Original languageEnglish (US)
Pages (from-to)H1495-H1500
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume287
Issue number4 56-4
DOIs
StatePublished - Oct 1 2004

Keywords

  • Antioxidants
  • Myosin light chain phosphatase
  • Smooth muscle contraction

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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