title: Darbepoetin alfa suppresses tumor necrosis factor-α-induced endothelin-1 production through antioxidant action in human aortic endothelial cells: role of sialic acid residues.
abstract: Recombinant human erythropoietin (r-HuEPO) is widely used to correct anemia in end-stage renal disease patients, who commonly suffer from atherosclerosis. Endothelin-1 (ET-1) has been implicated in the pathogenesis of atherosclerosis. Here, we tested whether darbepoetin alfa, a hypersialylated analogue of r-HuEPO, regulates tumor necrosis factor-α (TNF-α)-induced ET-1 production in human aortic endothelial cells, and sought to identify the signal pathways involved. Darbepoetin alfa attenuated TNF-α-induced ET-1 production. It also diminished TNF-α-induced reactive oxygen species (ROS) accumulation and subsequent activation of c-Jun NH2-terminal kinase (JNK), which regulates the DNA-binding activities of both AP-1 and NF-κB required for ET-1 gene transcription. Like a JNK inhibitor, darbepoetin alfa did not affect IκBα degradation or p65 nuclear translocation, but did inhibit mitogen- and stress-activated protein kinase 1 (MSK1) activation and attenuated p65 phosphorylation (serine 276), effects that may account for the reduction in NF-κB DNA-binding activity. Desialylation completely abolished darbepoetin alfa's inhibitory effects on TNF-α-induced ROS accumulation, MSK1 activation, and ET-1 gene expression, without affecting its stimulation of STAT5 activity. These data demonstrate that darbepoetin alfa suppresses TNF-α-induced ET-1 production through its antioxidant action and suggest that the sialic acid residues of darbepoetin alfa are essential for its antioxidant effect, possibly by scavenging ROS.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Asan Medical Center, College of Medicine, University of Ulsan, Seoul 138-736, Korea.
authors.forename: Won Seok
authors.initials: WS
authors.lastname: Yang
authors.forename: Jai Won
authors.initials: JW
authors.lastname: Chang
authors.forename: Nam Jeong
authors.initials: NJ
authors.lastname: Han
authors.forename: Su-Kil
authors.initials: SK
authors.lastname: Park
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D001011:Aorta / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D000068256:Darbepoetin alfa; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D019332:Endothelin-1 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D004921:Erythropoietin / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D019158:N-Acetylneuraminic Acid / Q000378:metabolism*; D010766:Phosphorylation; D017382:Reactive Oxygen Species / Q000378:metabolism; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction; D051996:Transcription Factor RelA / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000975:Antioxidants; D019332:Endothelin-1; D017382:Reactive Oxygen Species; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D004921:Erythropoietin; D000068256:Darbepoetin alfa; D038744:Ribosomal Protein S6 Kinases, 90-kDa; C116919:mitogen and stress-activated protein kinase 1; D019158:N-Acetylneuraminic Acid