Influence of recombinant hematopoietins and of fetal bovine serum on the globin synthetic pattern of human BFUe.
We have studied the effects of recombinant hematopoietic growth factors, granulocyte-macrophage colony-stimulating factor (GM-CSF) and/or interleukin-3 (IL-3) on the globin program of adult human erythroid progenitors (BFUe) stimulated to terminal differentiation by erythropoietin under fetal bovine serum (FBS)-supplemented or FBS-deprived culture conditions. Fetal globin production by BFUe-derived erythroblasts was assessed at the protein and mRNA level and its cellular distribution was evaluated by immunofluorescence. Although hemoglobinization and maturation of BFUe-derived erythroblasts was by and large comparable in FBS-replete versus FBS-deprived cultures, the latter had significantly less (up to 20-fold) gamma-globin and gamma-globin mRNA levels. Reduced gamma-globin in serum-deprived cultures was also reflected by a smaller proportion of erythroblasts with detectable gamma-globin by immunofluorescence. Erythroid bursts induced by either GM-CSF or IL-3 produced similar levels of gamma-globin both in FBS-supplemented and in FBS-deprived cultures. These results, obtained even in cultures of highly enriched BFUe, suggest that GM-CSF and IL-3, although they significantly increase the number and size of erythroid bursts, do not by themselves exert a direct influence on the level of fetal globin synthesis. By contrast, factor(s) present in FBS appear to exert a dominant influence on fetal globin synthesis in vitro. Although FBS-deprived conditions appear to largely abrogate the in vitro activation of fetal hemoglobin (Hb F) in normal samples, they do support increased Hb F production in samples from patients with hereditary persistence of fetal hemoglobin or from cord blood.
Department of Medicine, University of Washington, Seattle 98195.
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AR
Migliaccio
G
G
Migliaccio
M
M
Brice
P
P
Constantoulakis
G
G
Stamatoyannopoulos
T
T
Papayannopoulou
D001773:Blood Cells / Q000166:cytology / Q000378:metabolism; D001853:Bone Marrow / Q000378:metabolism; D001854:Bone Marrow Cells; D002478:Cells, Cultured; D003115:Colony-Stimulating Factors / Q000494:pharmacology*; D015672:Erythroid Precursor Cells / Q000378:metabolism*; D005319:Fetal Hemoglobin / Q000096:biosynthesis*; D005455:Fluorescent Antibody Technique; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000494:pharmacology
D003115:Colony-Stimulating Factors; D006133:Growth Substances; D007377:Interleukin-3; D011994:Recombinant Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D005319:Fetal Hemoglobin