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 language | English (US) |
|---|---|
| Pages (from-to) | H1495-H1500 |
| Journal | American Journal of Physiology - Heart and Circulatory Physiology |
| Volume | 287 |
| Issue number | 4 56-4 |
| DOIs | |
| State | Published - Oct 1 2004 |
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Keywords
- Antioxidants
- Myosin light chain phosphatase
- Smooth muscle contraction
ASJC Scopus subject areas
- Physiology
- Cardiology and Cardiovascular Medicine
- Physiology (medical)
Cite this
Activation of Rho/Rho kinase signaling pathway by reactive oxygen species in rat aorta. / Jin, Liming; Ying, Zhekang; Webb, R. Clinton.
In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 287, No. 4 56-4, 01.10.2004, p. H1495-H1500.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Activation of Rho/Rho kinase signaling pathway by reactive oxygen species in rat aorta
AU - Jin, Liming
AU - Ying, Zhekang
AU - Webb, R. Clinton
PY - 2004/10/1
Y1 - 2004/10/1
N2 - 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.
AB - 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.
KW - Antioxidants
KW - Myosin light chain phosphatase
KW - Smooth muscle contraction
UR - http://www.scopus.com/inward/record.url?scp=4744347777&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=4744347777&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.01006.2003
DO - 10.1152/ajpheart.01006.2003
M3 - Article
C2 - 15371261
AN - SCOPUS:4744347777
VL - 287
SP - H1495-H1500
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
SN - 0363-6135
IS - 4 56-4
ER -