title: Erythropoietin attenuates 6-hydroxydopamine-induced apoptosis via glycogen synthase kinase 3β-mediated mitochondrial translocation of Bax in PC12 cells.
abstract: The aim of this study was to determine the mechanism by which erythropoietin (EPO) suppressed 6-hydroxydopamine (6-OHDA)-induced apoptosis. Our results showed that 6-OHDA remarkably decreased phosphorylation of glycogen synthase kinase 3β (GSK3β) as well as enhanced the level of Bax in the mitochondria. Besides, 6-OHDA decreased the mitochondrial expression of Bcl-2 without altering the cytoplasmic expression of Bcl-2. In line with these results, 6-OHDA treatment enhanced the apoptosis and caspase 3 activity in PC12 cells. These findings indicated that mitochondrial dysfunction was involved in the neurotoxicity of 6-OHDA and GSK3β might act upstream of Bax/Bcl-2 and the caspase 3 pathways in 6-OHDA-treated PC12 cells. Furthermore, EPO reduced 6-OHDA-induced growth inhibition. Western blot exhibited that GSK3β inhibitor 4-benzyl-2-methyl-1, 2,4-thiadiazolidine-3, 5-dione (TDZD8) and EPO not only increased the phosphorylation of GSK3β but also inhibited the mitochondrial translocation of Bax. In agreement with these results, EPO and TDZD8 obviously increased the mitochondrial expression of Bcl-2. Finally, TDZD-8 and EPO significantly suppressed the enhanced apoptosis and activity of caspase 3 induced by 6-OHDA. Taken together, GSK3β-mediated mitochondrial cell death pathway is involved in the neuroprotective effect of EPO against 6-OHDA-induced apoptosis.
authors.affiliation: Department of Neurology, Second Affiliated Hospital of Soochow University, and Institute of Neuroscience, Soochow University, Jiangsu Province, China.
authors.forename: Xu-Hua
authors.initials: XH
authors.lastname: Ge
authors.forename: Guo-Ji
authors.initials: GJ
authors.lastname: Zhu
authors.forename: De-Qin
authors.initials: DQ
authors.lastname: Geng
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Zhang
authors.forename: Chun-Feng
authors.initials: CF
authors.lastname: Liu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3 / Q000378:metabolism / Q000502:physiology; D061945:Caspase Inhibitors / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004921:Erythropoietin / Q000502:physiology*; D038362:Glycogen Synthase Kinase 3 / Q000502:physiology*; D000071679:Glycogen Synthase Kinase 3 beta; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D016627:Oxidopamine / Q000037:antagonists & inhibitors / Q000633:toxicity*; D016716:PC12 Cells; D051381:Rats; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: C494828:Bax protein, rat; D061945:Caspase Inhibitors; D024101:Mitochondrial Proteins; D051028:bcl-2-Associated X Protein; D004921:Erythropoietin; D016627:Oxidopamine; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D038362:Glycogen Synthase Kinase 3; D053148:Caspase 3