caa a22 4500 445823429 CHVBK 20180317145251.0 cr unu---uuuuu 170323e20110301xx s 000 0 eng 10.1007/s10616-011-9345-x doi (NATIONALLICENCE)springer-10.1007/s10616-011-9345-x An extra high dose of erythropoietin fails to support the proliferation of erythropoietin dependent cell lines [Elektronische Daten] [Satoshi Abe, Ryuzo Sasaki, Seiji Masuda] Erythropoietin is responsible for the red blood cell formation by stimulating the proliferation and the differentiation of erythroid precursor cells. Erythropoietin triggers the conformational change in its receptor thereby induces the phosphorylation of JAK2. In this study, we show that an extra high dose of erythropoietin, however, fails to activate the erythropoietin receptor, to stimulate the phosphorylation of JAK2 and to support the cell proliferation of Ep-FDC-P2 cell. Moreover, high dose of EPO also inhibited the proliferation of various erythropoietin-dependent cell lines, suggesting that excess amount of EPO could not trigger the conformational change of the receptor. In the presence of an extra high dose of erythropoietin as well as in the absence of erythropoietin, the cells caused the DNA fragmentation, a typical symptom of apoptosis. The impairment of cell growth and the DNA fragmentation at the extremely high concentration of EPO was rescued by the addition of erythropoietin antibody or soluble form of erythropoietin receptor by titrating the excess erythropoietin. These results suggest that two erythropoietin binding sites on erythropoietin receptor dimer should be occupied by a single erythropoietin molecule for the proper conformational change of the receptor and the signal transduction of erythropoietin, instead, when two erythropoietin binding sites on the receptor are shared by two erythropoietin molecules, it fails to evoke the conformational change of erythropoietin receptor adequate for signal transduction. Springer Science+Business Media B.V., 2011 Erythropoietin nationallicence Erythropoietin receptor nationallicence JAK2 nationallicence Apoptosis nationallicence Antibody nationallicence Phosphorylation nationallicence Proliferation nationallicence Fragmentation nationallicence EPO : Erythropoietin nationallicence EPOR : EPO receptor nationallicence sEPOR : Soluble form of EPOR nationallicence CFU-E : Colony-forming unit erythroid nationallicence IL-3 : Interleukin-3 nationallicence MEM : Minimum essential medium nationallicence FCS : Fetal calf serum nationallicence MTX : Methotrexate nationallicence MTT : 3-(4,5-dimethythiazol-2-yl)-2, 5-diphenyl tetrazolium bromide nationallicence JAK : Janus family of nonreceptor-type protein tyrosine kinase nationallicence STAT : Signal transducers and activators of transcription nationallicence Abe Satoshi Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, 606-8502, Kyoto, Japan aut Sasaki Ryuzo Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, 606-8502, Kyoto, Japan aut Masuda Seiji Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, 606-8502, Kyoto, Japan aut Cytotechnology Springer Netherlands 63/2(2011-03-01), 101-109 0920-9069 63:2<101 2011 63 10616 https://doi.org/10.1007/s10616-011-9345-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10616-011-9345-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Abe Satoshi Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, 606-8502, Kyoto, Japan aut NATIONALLICENCE 700 1- Sasaki Ryuzo Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, 606-8502, Kyoto, Japan aut NATIONALLICENCE 700 1- Masuda Seiji Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, 606-8502, Kyoto, Japan aut NATIONALLICENCE 773 0- Cytotechnology Springer Netherlands 63/2(2011-03-01), 101-109 0920-9069 63:2<101 2011 63 10616 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer