TY - JOUR
T1 - Regulation of the vascular extracellular superoxide dismutase by nitric oxide and exercise training
AU - Fukai, Tohru
AU - Siegfried, Martin R.
AU - Ushio-Fukai, Masuko
AU - Cheng, Yian
AU - Kojda, Georg
AU - Harrison, David G.
PY - 2000/6
Y1 - 2000/6
N2 - The bioactivity of endothelium-derived nitric oxide (NO) reflects its rates of production and of inactivation by superoxide (O2·-), a reactive species dismutated by extracellular superoxide dismutase (ecSOD). We have now examined the complementary hypothesis, namely that NO modulates ecSOD expression. The NO donor DETA-NO increased ecSOD expression in a time- and dose-dependent manner in human aortic smooth muscle cells. This effect was prevented by the guanylate cyclase inhibitor ODQ and by the protein kinase G (PKG) inhibitor Rp-8-CPT-cGMP. Expression of ecSOD was also increased by 8- bromo-cGMP, but not by 8-bromo-cAMP. Interestingly, the effect of NO on ecSOD expression was prevented by inhibition of the MAP kinase p38 but not of the MAP kinase kinase p42/44, suggesting that NO modulates ecSOD expression via cGMP/PKG and p38MAP kinase-dependent pathways, but not through p42/44MAP kinase. In aortas from mice lacking the endothelial nitric oxide synthase (eNOS), ecSOD was reduced more than twofold compared to controls. Treadmill exercise training increased eNOS and ecSOD expression in wild-type mice but had no effect on ecSOD expression in mice lacking eNOS, suggesting that this effect of exercise is meditated by endothelium-derived NO. Upregulation of ecSOD expression by NO may represent an important feed-forward mechanism whereby endothelial NO stimulates ecSOD expression in adjacent smooth muscle cells, thus preventing O2·--mediated degradation of NO as it traverses between the two cell types.
AB - The bioactivity of endothelium-derived nitric oxide (NO) reflects its rates of production and of inactivation by superoxide (O2·-), a reactive species dismutated by extracellular superoxide dismutase (ecSOD). We have now examined the complementary hypothesis, namely that NO modulates ecSOD expression. The NO donor DETA-NO increased ecSOD expression in a time- and dose-dependent manner in human aortic smooth muscle cells. This effect was prevented by the guanylate cyclase inhibitor ODQ and by the protein kinase G (PKG) inhibitor Rp-8-CPT-cGMP. Expression of ecSOD was also increased by 8- bromo-cGMP, but not by 8-bromo-cAMP. Interestingly, the effect of NO on ecSOD expression was prevented by inhibition of the MAP kinase p38 but not of the MAP kinase kinase p42/44, suggesting that NO modulates ecSOD expression via cGMP/PKG and p38MAP kinase-dependent pathways, but not through p42/44MAP kinase. In aortas from mice lacking the endothelial nitric oxide synthase (eNOS), ecSOD was reduced more than twofold compared to controls. Treadmill exercise training increased eNOS and ecSOD expression in wild-type mice but had no effect on ecSOD expression in mice lacking eNOS, suggesting that this effect of exercise is meditated by endothelium-derived NO. Upregulation of ecSOD expression by NO may represent an important feed-forward mechanism whereby endothelial NO stimulates ecSOD expression in adjacent smooth muscle cells, thus preventing O2·--mediated degradation of NO as it traverses between the two cell types.
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U2 - 10.1172/jci9551
DO - 10.1172/jci9551
M3 - Article
C2 - 10841522
AN - SCOPUS:0034201168
SN - 0021-9738
VL - 105
SP - 631
EP - 1639
JO - Journal of Clinical Investigation
JF - Journal of Clinical Investigation
IS - 11
ER -