Regulation of human megakaryocytopoiesis: analysis of proliferation, ploidy and maturation in liquid cultures.
A liquid culture technique associated with either double staining and flow cytometry or electron microscopy was used to study human megakaryocytopoiesis. During development from the embryo to the adult, a progressive increase in ploidy classes associated with an enhancement of megakaryocyte (meg) size was observed. Granulocyte-macrophage colony-stimulating factor had no effects on adult marrow cultures. In contrast, interleukin (IL) 3 induced a marked proliferation, but was unable to promote polyploidization. Furthermore, it abrogated the effects on endomitosis of aplastic plasma (AP). This negative effect on polyploidization of IL-3 could be partially dissociated from its effects on proliferation by a delayed addition in culture. AP acted on both proliferation and endoreplication, which was not due to the main hematopoietic growth factors, including IL-6. A synthesis of IL-6 was detected by in situ hybridization in cultured cells including megs which also express receptors for IL-6. These results suggest that terminal meg differentiation may be regulated by an autocrine IL-6 loop, and that megakaryocytopoiesis may be independently regulated at early and late stages of differentiation.
INSERM U.91, Hôpital Henri Mondor, Créteil, France.
E
E
Hegyi
S
S
Navarro
N
N
Debili
M A
MA
Mouthon
A
A
Katz
J
J
Breton-Gorius
W
W
Vainchenker
D001345:Autoradiography; D002455:Cell Division / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D003115:Colony-Stimulating Factors / Q000502:physiology; D004247:DNA / Q000235:genetics; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D006133:Growth Substances / Q000502:physiology; D006801:Humans; D007377:Interleukin-3 / Q000502:physiology; D015850:Interleukin-6 / Q000502:physiology; D008533:Megakaryocytes / Q000166:cytology* / Q000648:ultrastructure; D009693:Nucleic Acid Hybridization; D011003:Ploidies; D011994:Recombinant Proteins; D013921:Thrombocytopenia / Q000097:blood
D003115:Colony-Stimulating Factors; D006133:Growth Substances; D007377:Interleukin-3; D015850:Interleukin-6; D011994:Recombinant Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D004247:DNA