Studies on the reversibility of protein S-thiolation in human endothelial cells.
Exposure of human umbilical vein endothelial cells to oxidants, such as hydrogen peroxide and diamide, has been shown to induce protein-specific S-thiolation of cellular proteins. In this study we have now identified glutathione (reduced form) as the major low molecular-weight thiol that is bound to protein substrates in human umbilical vein endothelial (HUVE) cells during oxidative stress and investigated the dose- and time-response relationship of diamide- and hydrogen peroxide-induced 8-thiolation of HUVE cell protein. Intact HUVE cells are able to rapidly reduce S-thiolated proteins with almost quantitative reappearance of reduced glutathione in the cells and protection from acute, lytic cytotoxicity. Additionally, studies were performed with detergent-solubilized cell extracts to determine the nature of the reductants operating in HUVE cells to maintain protein thiol homeostasis. The results clearly show the involvement of NADH- and NADPH-dependent systems. These data suggest that the reversible S-thiolation of proteins in these human endothelial cells may represent a significant cellular antioxidant and regulatory mechanism during oxidative stress.
Schuppe-Koistinen
I
I
Division of Toxicology, Karolinska Institutet, Stockholm, Sweden.
Gerdes
R
R
Moldéus
P
P
Cotgreave
I A
IA
D002478:Cells, Cultured; D003958:Diamide / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000378:metabolism*; D005949:Glucose Oxidase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D018384:Oxidative Stress; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D013879:Thioredoxins / Q000378:metabolism
D011506:Proteins; D009243:NAD; D003958:Diamide; D013879:Thioredoxins; D005949:Glucose Oxidase; D005978:Glutathione