title: Vitamin B6 suppresses apoptosis of NM-1 bovine endothelial cells induced by homocysteine and copper.
abstract: Hyperhomocysteinemia is an important risk factor for atherosclerosis. We previously reported that formation of early atherosclerosis in the rat aorta was associated with hyperhomocysteinemia and reduction of antioxidant activity caused by low concentration of vitamin B(6)in vivo. In the present study, we examined effects of vitamin B(6) on apoptosis of bovine endothelial cells (NM-1 cells) treated with homocysteine and copper. Homocysteine and copper induced extracellular hydrogen peroxide, intracellular ROS and cellular lipid peroxide levels. Cell viability was reduced to 30% compared to that of control cells. On the other hand, pyridoxal treatment as well as EDTA treatment increased viability of NM-1 cells treated with homocysteine and copper to about 60%, and significantly decreased extracellular hydrogen peroxide, intracellular ROS and cellular lipid peroxide levels. The treatment of catalase recovered cell viability and reduced the level of extracellular hydrogen peroxide and intracellular ROS. Cell death by homocysteine and copper was confirmed to be due to apoptosis by evaluation of DNA fragmentation and by TUNEL assay. However, apoptosis of NM-1 cells induced by homocysteine and copper was due to a caspase-independent pathway as it was not inhibited by the caspase inhibitor, Z-VAD-fmk. Apoptosis of NM-1 cells induced by homocysteine and copper accompanied with mitochondrial permeability but not cytochrome c release. These results suggest that pyridoxal treatment suppresses apoptosis of NM-1 cells induced by homocysteine and copper, most likely through antioxidant effects.
authors.affiliation: Department of Veterinary Medicine, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Endo
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nishiyama
authors.forename: Masaaki
authors.initials: M
authors.lastname: Okabe
authors.forename: Mitsuharu
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kanouchi
authors.forename: Tatsuzo
authors.initials: T
authors.lastname: Oka
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002374:Catalase / Q000494:pharmacology; D002417:Cattle; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D019327:Copper Sulfate / Q000633:toxicity*; D053938:DNA Fragmentation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D006710:Homocysteine / Q000633:toxicity*; D006861:Hydrogen Peroxide / Q000378:metabolism; D020287:In Situ Nick-End Labeling; D015227:Lipid Peroxidation / Q000187:drug effects; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D011730:Pyridoxal / Q000494:pharmacology; D011733:Pyridoxamine / Q000494:pharmacology; D011736:Pyridoxine / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D025101:Vitamin B 6 / Q000494:pharmacology*
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D017392:Thiobarbituric Acid Reactive Substances; D006710:Homocysteine; D011730:Pyridoxal; D011733:Pyridoxamine; D025101:Vitamin B 6; D006861:Hydrogen Peroxide; D002374:Catalase; D011736:Pyridoxine; D019327:Copper Sulfate