Peroxynitrite induces haem oxygenase-1 in vascular endothelial cells: a link to apoptosis.
Peroxynitrite (ONOO-) is a potent oxidizing agent generated by the interaction of nitric oxide (NO) and the superoxide anion. In physiological solution, ONOO- rapidly decomposes to a hydroxyl radical, one of the most reactive free radicals, and nitrogen dioxide, another species able to cause oxidative damage. In the present study we investigated the effect of ONOO- on the expression of haem oxygenase-1 (HO-1), an inducible protein that is highly up-regulated by oxidative stress. Exposure of bovine aortic endothelial cells to ONOO- (250-1000 microM) produced a concentration-dependent increase in haem oxygenase activity and HO-1 protein expression. This effect was completely abolished by the ONOO- scavengers uric acid and N-acetylcysteine, and partly attenuated by 1,3-dimethyl-2-thiourea, a scavenger of hydroxyl radicals. ONOO- also produced a concentration-dependent increase in apoptosis and cytotoxicity, which were considerably decreased by uric acid and N-acetylcysteine. A 70% decrease in apoptosis was observed when cells were exposed to ONOO- in the presence of 10 microM tin protoporphyrin IX (SnPPIX), an inhibitor of haem oxygenase activity. When SnPPIX was added 5 min after ONOO-, apoptosis decreased by only 40%, which suggests that an interaction between ONOO- and the protoporphyrin occurs in our system. Increased haem oxygenase activity by pretreatment of cells with haemin resulted in elevated bilirubin production and was associated with a substantial decrease (35%) in ONOO--mediated apoptosis. These results indicate the ability of ONOO- to modulate the expression of the stress protein HO-1 and suggest that the haem oxygenase pathway contributes to protection against the cytotoxic action of ONOO-.
Foresti
R
R
Vascular Biology Unit, Department of Surgical Research, Northwick Park Institute for Medical Research, Harrow, Middlesex HA1 3UJ, UK. r.foresti@ic.ac.uk
Sarathchandra
P
P
Clark
J E
JE
Green
C J
CJ
Motterlini
R
R
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001011:Aorta / Q000166:cytology; D017209:Apoptosis / Q000187:drug effects*; D001663:Bilirubin / Q000378:metabolism; D002417:Cattle; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects*; D016166:Free Radical Scavengers / Q000494:pharmacology; D006419:Heme Oxygenase (Decyclizing) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051547:Heme Oxygenase-1; D006427:Hemin / Q000494:pharmacology; D008665:Metalloporphyrins / Q000494:pharmacology; D009566:Nitrates / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011524:Protoporphyrins / Q000494:pharmacology; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology; D013997:Time Factors; D014527:Uric Acid / Q000494:pharmacology
D000975:Antioxidants; D016166:Free Radical Scavengers; D008665:Metalloporphyrins; D009566:Nitrates; D011524:Protoporphyrins; C039642:peroxynitric acid; D014527:Uric Acid; D006427:Hemin; C038983:1,3-dimethylthiourea; C032628:tin protoporphyrin IX; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; D013890:Thiourea; D001663:Bilirubin; D000111:Acetylcysteine