title: Erythropoietin protects against 6-hydroxydopamine-induced dopaminergic cell death.
abstract: Parkinson's disease (PD) is a neurodegenerative disorder characterized by the death of midbrain dopaminergic neurons. In the present study, erythropoietin, a trophic factor that has both hematopoietic and neural protective characteristics, was investigated for its capacity to protect dopaminergic neurons in experimental Parkinson's disease. Using both the dopaminergic cell line, MN9D, and primary dopamine neurons, we show that erythropoietin (1-3 U/mL) is neuroprotective against the dopaminergic neurotoxin, 6-hydroxydopamine. Protection was mediated by the erythropoietin receptor, as neutralizing anti-erythropoietin receptor antibody abrogated the protection. Activation of Akt/protein kinase B (PKB), via the phosphoinositide 3-kinase pathway, is a critical mechanism in erythropoietin-induced protection, while activation of extracellular signal-regulated kinase (ERK)1/2 contributes only moderately. Indeed, transfection of constitutively active Akt/PKB into dopaminergic cells was sufficient to protect against cell death. Furthermore, erythropoietin diminished markers of apoptosis in MN9D cells, including caspase 9 and caspase 3 activation and internucleosomal DNA fragmentation, suggesting that erythropoietin interferes with the apoptosis-execution process. When erythropoietin was administered to mice unilaterally lesioned with 6-hydroxydopamine, it prevented the loss of nigral dopaminergic neurons and maintained striatal catecholamine levels for at least 8 weeks. Erythropoietin-treated mice also had significantly reduced behavioral asymmetries. These studies suggest that erythropoietin can be an effective neuroprotective agent for dopaminergic neurons, and may be useful in reversing behavioral deficits associated with Parkinson's disease.
authors.affiliation: Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
authors.forename: Armando P
authors.initials: AP
authors.lastname: Signore
authors.forename: Zhongfang
authors.initials: Z
authors.lastname: Weng
authors.forename: Teresa
authors.initials: T
authors.lastname: Hastings
authors.forename: Amber D
authors.initials: AD
authors.lastname: Van Laar
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Liang
authors.forename: Yong J
authors.initials: YJ
authors.lastname: Lee
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001522:Behavior, Animal / Q000187:drug effects; D015415:Biomarkers / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D004298:Dopamine / Q000378:metabolism*; D004921:Erythropoietin / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009498:Neurotoxins / Q000494:pharmacology*; D016627:Oxidopamine / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism
chemical_list: D015415:Biomarkers; D018696:Neuroprotective Agents; D009498:Neurotoxins; D004921:Erythropoietin; D016627:Oxidopamine; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D004298:Dopamine