title: Adenosine-dependent induction of glutathione peroxidase 1 in human primary endothelial cells and protection against oxidative stress.
abstract: Cellular glutathione peroxidase (GPx-1), a selenocysteine-containing enzyme, plays a central role in protecting cells from oxidative injury. GPx-1 is ubiquitously expressed in eukaryotic cells where it reduces hydrogen and lipid peroxides to alcohols. Adenosine, which is released from stressed or injured cells, protects against ischemia/reperfusion injury and apoptosis. In this study, we hypothesize that the cytoprotective effect of adenosine involves an increase in the activity of GPx-1. Treatment of human primary pulmonary artery endothelial cells (HPAECs) with 50 micromol/L adenosine in the presence of 10 micromol/L erytho-9-(2-hydroxy-3-nonyl)adenine (EHNA), an adenosine deaminase inhibitor, for 48 hours increased GPx-1 mRNA levels 2-fold. GPx-1 protein and enzyme activity also increased approximately 2-fold after treatment. The induction of GPx-1 expression was found to be a consequence of increased mRNA stability and not an increase in transcription. Bisindolylmaleimide I (BIM), a protein kinase C signaling pathway inhibitor, significantly attenuated the induction of GPx-1 mRNA by approximately 36%. The adenosine/EHNA-treated cells were more resistant to hydrogen peroxide stress. Both pharmacological inhibition and siRNA knockdown of GPx-1 attenuated the protective affect of adenosine/EHNA treatment, indicating that the adenosine-induced increase in GPx-1 contributes to an increase in cellular protection against oxidative stress. These data suggest that adenosine may protect the cardiovascular system from ischemia/reperfusion injury, in part, by enhancing the expression of the central intracellular antioxidant enzyme, GPx-1.
authors.affiliation: Whitaker Cardiovascular Institute and Evans Department of Medicine, Boston University School of Medicine, Boston, Mass 02118, USA.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Zhang
authors.forename: Diane E
authors.initials: DE
authors.lastname: Handy
authors.forename: Joseph
authors.initials: J
authors.lastname: Loscalzo
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000241:Adenosine / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology*; D004790:Enzyme Induction; D005979:Glutathione Peroxidase / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D018384:Oxidative Stress; D011493:Protein Kinase C / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D018047:Receptors, Purinergic P1 / Q000502:physiology; D015398:Signal Transduction; D000094765:Glutathione Peroxidase GPX1
chemical_list: D012333:RNA, Messenger; D018047:Receptors, Purinergic P1; C010192:9-(2-hydroxy-3-nonyl)adenine; D006861:Hydrogen Peroxide; D005979:Glutathione Peroxidase; D011493:Protein Kinase C; D000225:Adenine; D000241:Adenosine; D000094765:Glutathione Peroxidase GPX1; C000722067:GPX1 protein, human