Synergistic effects of erythropoietin and interleukin-6 on the in vitro proplatelet process formation of rat megakaryocytes.
The recombinant hemopoietic factors of megakaryocyte potentiator (MEG-POT) were studied to compare their activity in stimulating proplatelet process formation (PPF) with thrombopoietin (TPO, c-MpI ligand). For the assay, a highly enriched (> 95%) population of more than 90% viable megakaryocytes was isolated from rat bone marrow using the immunomagnetic beads method and cultured with fetal calf serum (FCS) or in a serum-free condition. Megakaryocytes developing slender beaded cytoplasmic processes (proplatelet processes) were observed on both inverted phase contract microscopy and scanning electron microscopy. A large number of proplatelet process clusters were dose-dependently formed with the addition of varying doses of recombinant erythropoietin (rEpo) and interleukin-6 (rIL-6) as well as TPO. Epo and IL-6 were demonstrated to act synergistically solely at low doses in the development of PPF (P < 0.05). Other recombinant factors such as IL-11, leukemia inhibitory factor (LIF) and erythroid differentiation factor (EDF) appeared weak or ineffective. From these in vitro observations, it was suggested that a synergism of Epo and IL-6 might play a significant role in the terminal stage of megakaryocyte maturation leading to platelet release.
Tange
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T
Department of Pathology, Faculty of Medicine, University of Tokyo, Japan.
Miyazaki
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H
D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D001853:Bone Marrow / Q000187:drug effects; D001854:Bone Marrow Cells; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004921:Erythropoietin / Q000494:pharmacology*; D005260:Female; D015850:Interleukin-6 / Q000494:pharmacology*; D008533:Megakaryocytes / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000494:pharmacology; D013047:Specific Pathogen-Free Organisms; D013926:Thrombopoietin / Q000502:physiology
D015850:Interleukin-6; D011994:Recombinant Proteins; D004921:Erythropoietin; D013926:Thrombopoietin