Regulation of Cu,Zn-superoxide dismutase in bovine pulmonary artery endothelial cells.
To evaluate the regulation of endothelial cell Cu,Zn-SOD, we have exposed bovine pulmonary artery endothelial cells in culture to hyperoxia and hypoxia, second messengers or related agonists, hormones, free radical generating systems, endotoxin, and cytokines and have measured Cu,Zn-SOD protein of these cells by an ELISA developed in our laboratory. Control preconfluent and confluent cells in room air contained 196 +/- 18 ng Cu,Zn-SOD/10(6) cells. A23187 (0.33 microM), forskolin (10 microM), isobutylmethylxanthine (0.1 mM), dexamethasone (1 microM), triiodothyronine (1 microM) and retinoic acid (1 microM) failed to alter this level of Cu,Zn-SOD. Exposure to anoxia and hyperoxia both elevated the level approximately 1.5-2.0-fold over 20% oxygen-exposed controls at 48-72 hr. Similarly, exposures to glucose oxidase (0.0075 units/ml), menadione (12.5 microM), xanthine-xanthine oxidase (10 microM, 0.03 units/ml) and H2O2 (0.0005%) increased the level up to two-threefold over controls at 24-48 hr. Lipopolysaccharide, TGF beta 1, TNF alpha, and Il-1 also increased levels of cellular Cu,Zn-SOD, but only in proliferating cells. Il-2, Il-4, interferon-gamma, and GM-CSF had no effect on Cu,Zn-SOD. All treatments that elevated SOD resulted in inhibition of cellular growth, but decreased growth of cells at confluence alone was not associated with increased Cu,Zn-SOD. We propose from these studies that Cu,Zn-SOD of endothelial cells is not under conventional second messenger or hormonal regulation, but that up-regulation of the enzyme is associated with (and perhaps stimulated by) free-radical or oxidant production that also may be influenced by availability of certain cytokines under replicating conditions.
Kong
X J
XJ
Department of Medicine, New England Medical Center, Boston, Massachusetts 02111.
Fanburg
B L
BL
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002455:Cell Division; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D016207:Cytokines / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology*; D006728:Hormones / Q000494:pharmacology; D000860:Hypoxia / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D010100:Oxygen / Q000378:metabolism; D011651:Pulmonary Artery / Q000166:cytology / Q000201:enzymology*; D017382:Reactive Oxygen Species / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000378:metabolism*
D016207:Cytokines; D006728:Hormones; D008070:Lipopolysaccharides; D017382:Reactive Oxygen Species; D000242:Cyclic AMP; D013482:Superoxide Dismutase; D010100:Oxygen; D002118:Calcium