title: Response of human endothelial cell antioxidant enzymes to hyperoxia.
abstract: To explore the level of regulation of the expression of the major antioxidant enzymes in response to hyperoxia, we exposed human umbilical vein endothelial cells to 95% O2 for 3 and 5 days and measured (1) the steady-state mRNA levels, (2) the activities, and (3) the immunoreactive content of CuZn and Mn superoxide dismutases (SOD), catalase (CAT), and glutathione peroxidase (GP). We found that a 3-day exposure to 95% O2 caused (1) an increase in CuZnSOD mRNA (by 41%), CAT mRNA (by 26%), and GP mRNA (by 173%); (2) an increase in CuZnSOD activity (by 30%), a decrease in CAT activity (by 37%), and an increase in GP activity (by 60%); and (3) an increase in CuZnSOD immunodetectable protein (by 26%) and a loss in CAT immunoreactive protein (by 27%). After a 5-day exposure to 95% O2, there was (1) a 93% increase in CuZnSOD mRNA, a 71% increase in CAT mRNA, and a 127% increase in GP mRNA; (2) a 56% increase in CuZnSOD activity, a 70% decrease in CAT activity, and an 89% increase in GP activity; and (3) a 35% increase in CuZnSOD immunoreactive protein and a 55% loss in CAT immunoreactive protein. There was no change in the steady-state MnSOD mRNA level after 3 days in 95% O2, but a 100% increase was observed on day 5 of oxygen exposure. MnSOD activity was unchanged in cells exposed to hyperoxia for 3 and 5 days. These data suggest that, in human umbilical vein endothelial cells, the regulation of antioxidant enzymes expression in response to O2 is complex and exerted at different levels.
authors.affiliation: Respiratory Division, University Hospital, Geneva, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Jornot
authors.forename: A F
authors.initials: AF
authors.lastname: Junod
mesh_terms: D000199:Actins / Q000378:metabolism; D004730:Endothelium, Vascular / Q000201:enzymology*; D005979:Glutathione Peroxidase / Q000378:metabolism; D006801:Humans; D010100:Oxygen / Q000378:metabolism* / Q000633:toxicity; D010544:Peroxidases / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry / Q000276:immunology; D012333:RNA, Messenger / Q000378:metabolism; D013482:Superoxide Dismutase / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D014471:Umbilical Veins
chemical_list: D000199:Actins; D011506:Proteins; D012333:RNA, Messenger; D010544:Peroxidases; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D010100:Oxygen