title: Synergistic and inhibitory interactions in the in vitro control of murine megakaryocyte colony formation.
abstract: The formation of megakaryocyte colonies in agar cultures of murine bone marrow or spleen cells can be stimulated by the addition of interleukin-3 (IL-3), erythropoietin (EPO), thrombopoietin (TPO), or IL-6. However, greater numbers of colonies developed if combinations of two or more of these stimuli were used, particularly combinations including stem cell factor, with maximal numbers of colonies developing with the combination of stem cell factor plus IL-3 plus EPO. The data indicate that most committed progenitor cells in the megakaryocyte lineage were unusual in that they required stimulation by two or more hematopoietic growth factors. In tests using a range of growth factors, G-CSF was exceptional in that it consistently specifically inhibited megakaryocyte colony formation stimulated by EPO, TPO, or IL-6 but not that stimulated by IL-3. The mechanisms involved in this inhibitory action of G-CSF are unknown, but the inhibitory action could be of relevance for the dose-dependent lowering of platelet levels observed in some subjects injected with G-CSF.
authors.affiliation: Division of Cancer and Hematology, The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia. metcalf@wehi.edu.au
authors.forename: Donald
authors.initials: D
authors.lastname: Metcalf
authors.forename: Ladina
authors.initials: L
authors.lastname: Di Rago
authors.forename: Sandra
authors.initials: S
authors.lastname: Mifsud
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects; D004336:Drug Antagonism; D004357:Drug Synergism; D004921:Erythropoietin / Q000494:pharmacology*; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D066298:In Vitro Techniques; D007377:Interleukin-3 / Q000494:pharmacology*; D008297:Male; D008533:Megakaryocytes / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000166:cytology; D019089:Stem Cell Factor / Q000494:pharmacology; D013234:Stem Cells / Q000166:cytology*; D013926:Thrombopoietin / Q000494:pharmacology*
chemical_list: D007377:Interleukin-3; D019089:Stem Cell Factor; D004921:Erythropoietin; D016179:Granulocyte Colony-Stimulating Factor; D013926:Thrombopoietin