Protective effects of tetrahydrobiopterin against nitric oxide-induced endothelial cell death.
The purpose of this study was to examine whether tetrahydrobiopterin (BH4), one of the cofactors of nitric oxide (NO) synthase, attenuates NO-induced endothelial cell death. S-Nitroso-N-acetyl-DL-penicillamine (SNAP) was used as a NO donor. Endothelial cell death was assessed by the leakage of intracellular lactate dehydrogenase (LDH). Addition of SNAP to endothelial cells time- and concentration-dependently induced endothelial cell death. The SNAP-induced endothelial cell death was strongly reduced by the treatment with carboxy-PTIO, a NO scavenger, or catalase, but not with superoxide dismutase (SOD). Moreover, pretreatment with sepiapterin, a precursor of BH4, increased intracellular BH4 content, and strongly reduced the SNAP-induced endothelial cell death. Both the increase in BH4 content and the protective effects of sepiapterin were prevented by co-pretreatment with N-acetylserotonin (NAS), an inhibitor of BH4 synthesis. These findings suggest that the cytotoxicity of NO released from SNAP involves H2O2 production, and increase in intracellular BH4 content attenuates NO-induced endothelial cell death. Scavenging of H2O2 by BH4 may be at least one of the mechanisms by which BH4 reduces NO-induced endothelial cell death.
Shimizu
S
S
Department of Pharmacology, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan.
Ishii
M
M
Kawakami
Y
Y
Momose
K
K
Yamamoto
T
T
D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology; D001708:Biopterins / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D002417:Cattle; D016923:Cell Death / Q000187:drug effects; D016207:Cytokines / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D004790:Enzyme Induction / Q000187:drug effects; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000633:toxicity; D009569:Nitric Oxide / Q000037:antagonists & inhibitors* / Q000502:physiology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052247:Nitric Oxide Synthase Type II; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D011621:Pteridines / Q000494:pharmacology; D011622:Pterins; D026423:S-Nitroso-N-Acetylpenicillamine; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology
D016207:Cytokines; D008070:Lipopolysaccharides; D011621:Pteridines; D011622:Pterins; D001708:Biopterins; D009569:Nitric Oxide; D012701:Serotonin; D026423:S-Nitroso-N-Acetylpenicillamine; C016727:sepiapterin; D007770:L-Lactate Dehydrogenase; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C003402:sapropterin; D010396:Penicillamine; C006389:N-acetylserotonin