Characterization of the Protective Effect of Tetrahydrobiopterin Against S-Nitroso-N -Acetyl-D ,L-Penicillamine Induced Endothelial Cell Injury

• Main Authors: Ishii Masakazu, Shimizu Shunichi, Momose Kazutaka, Kiuchi Yuji, Yamamoto Toshinori
• Format: Article
• Language: English
• Published: De Gruyter 1999-02-01
• Series: Pteridines
• Subjects: tetrahydrobiopterin; s-nitroso-n-acetyl-d,l-penicillamine; nitric oxide; cell injury; hydrogen peroxide; endothelial cells
• Online Access: https://doi.org/10.1515/pteridines.1999.10.1.14
• ISSN: 0933-4807; 2195-4720

The purpose of this study was to characterize the protective effect of tetrahydrobiopterin (BH4), one of the cofactors of nitric oxide (NO) synthase, against NO-induced endothelial cell injury. The addition of S-nitroso-N-acetyl-D,L-penicillamine (SNAP), a NO donor, to endothelial cells induced the release of lactate dehydrogenase (LDH), a marker for cell injury. The SNAP-induced endothelial cell injury was markedly reduced by pretreatment with sepiapterin, a precursor of BH4 synthesis. On the other hand, exogenous BH4 had little effect on the SNAP-induced endothelial cell injury. We recently found that NO-induced endothelial cell injury involves a part of H202 production, since the injury was blocked by the treatment with catalase. Although BH4 released reactive oxygen species (ROS) in cell-free conditions, the increase in intracellular BH4 by pretreatment with sepiapterin strongly reduced H202-induced intracellular oxidative stress. These findings suggest that the increase in intracellular BH4 content but not extracellular BH4, strongly attenuates NO-induced endothelial cell injury by at least one of the mechanisms by which BH4 reduces H202-induced oxidative stress. Intracellular BH4 seems mainly to play a role as an antioxidant or as a ROS-scavenger.