title: Erythropoietin promotes spinal cord-derived neural progenitor cell proliferation by regulating cell cycle.
abstract: Erythropoietin (EPO) regulates the proliferation and differentiation of erythroid cells by binding to its specific transmembrane receptor (EPOR). The presence of EPO and its receptor in the CNS suggests a different function for EPO other than erythropoiesis. The purpose of the present study was to examine EPOR expression and the role of EPO in the proliferation of neonatal spinal cord-derived neural progenitor cells. The effect of EPO on cell cycle progression was also examined, as well as the signaling cascades involved in this process. Our results showed that EPOR was present in the neural progenitor cells and EPO significantly enhanced their proliferation. Cell cycle analysis of EPO-treated neural progenitor cells indicated a reduced percentage of cells in G0/G1 phase, whereas the cell proliferation index (S phase plus G2/M phase) was increased. EPO also increased the proportion of 5-bromo-2-deoxyuridine (BrdU)-positive cells. With respect to the cell cycle signaling, we examined the cyclin-dependent kinases D1, D2 and E, and cyclin-dependent kinase inhibitors, p21cip1, p27kip1 and p57kip2. No significant differences were observed in the expression of these transcripts after EPO administration. Interestingly, the anti-apoptotic factors, mcl-1 and bcl-2 were significantly increased twofold. Moreover, these specific effects of EPO were eliminated by incubation of the progenitor cells with anti-EPO neutralizing antibody. Those observations suggested that EPO may play a role in normal spinal cord development by regulating cell proliferation and apoptosis.
authors.affiliation: Department of Spine Surgery, Second Affiliated Hospital of Harbin Medical University, Hei Long Jiang Province, PR China. wangyansong@ems.hrbmu.edu.cn
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Yao
authors.forename: C
authors.initials: C
authors.lastname: Zhou
authors.forename: D
authors.initials: D
authors.lastname: Dong
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
authors.forename: G
authors.initials: G
authors.lastname: Wei
authors.forename: X
authors.initials: X
authors.lastname: Cui
mesh_terms: D000818:Animals; D019138:Antibodies, Blocking / Q000494:pharmacology; D051017:Apoptosis Regulatory Proteins / Q000187:drug effects / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects* / Q000502:physiology; D018797:Cell Cycle Proteins / Q000187:drug effects / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D004921:Erythropoietin / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017467:Receptors, Erythropoietin / Q000819:agonists / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology*; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
chemical_list: D019138:Antibodies, Blocking; D051017:Apoptosis Regulatory Proteins; D018797:Cell Cycle Proteins; D017467:Receptors, Erythropoietin; D004921:Erythropoietin