Darbepoetin alfa suppresses tumor necrosis factor-α-induced endothelin-1 production through antioxidant action in human aortic endothelial cells: Role of sialic acid residues

• Published in: Free radical biology & medicine Vol. 50; no. 10; pp. 1242 - 1251
• Main Authors: Yang, Won Seok, Chang, Jai Won, Han, Nam Jeong, Park, Su-Kil
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15-05-2011
• Subjects: Antioxidants - metabolism; Aorta - cytology; Aorta - drug effects; Aorta - metabolism; Darbepoetin alfa; Endothelial Cells - drug effects; Endothelial Cells - metabolism; Endothelin-1; Endothelin-1 - biosynthesis; Endothelin-1 - genetics; Endothelin-1 - metabolism; Erythropoietin - analogs & derivatives; Erythropoietin - metabolism; Free radicals; Humans; Mitogen- and stress-activated protein kinase 1; N-Acetylneuraminic Acid - metabolism; p65 phosphorylation; Phosphorylation; Reactive oxygen species; Reactive Oxygen Species - metabolism; Ribosomal Protein S6 Kinases, 90-kDa - antagonists & inhibitors; Ribosomal Protein S6 Kinases, 90-kDa - metabolism; Sialic acid; Signal Transduction; Transcription Factor RelA - metabolism; Tumor Necrosis Factor-alpha - antagonists & inhibitors; Tumor Necrosis Factor-alpha - metabolism; Tumor necrosis factor-α; ESRD; Reactive oxygen species; Sialic acid; JNK; MSK1; AP-1; CM-H2DCF-DA; NF-κB; RT-PCR; EMSA; p65 phosphorylation; STAT5; r-HuEPO; Free radicals; SOD; Tumor necrosis factor-α; MAPK; NAC; ET-1; Mitogen- and stress-activated protein kinase 1; TNF-α; HAEC; ROS; Endothelin-1; Darbepoetin alfa; ERK
• ISSN: 0891-5849; 1873-4596
• DOI: 10.1016/j.freeradbiomed.2011.02.005

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.