Stromal cells retard the differentiation of CD34(+)CD38(low/neg) human primitive progenitors exposed to cytokines independent of their mitotic history.
Stem cell proliferation induced by potent cytokines usually leads to a loss of primitive potential through differentiation. In this study, the ability of cytokines and murine MS5 stromal cells to independently regulate the proliferation and long-term culture-initiating cell (LTC-IC) activity of primitive CD34(+)CD38(low/neg) human bone marrow cells was evaluated. To compare populations with identical proliferation histories, cells were labeled with carboxy fluorescein diacetate succinimidyl ester, and LTC-IC activity was assessed 4 days later in cells that had accomplished the same number of divisions with or without MS5 cells. MS5 cells counteracted dramatically the loss of LTC-IC activity observed in the presence of cytokines alone. Thus, in the presence of MS5 cells, means of 1233 (n = 5) and 355 (n = 9) LTC-IC-derived colony-forming cells (CFCs) were generated by 1000 cells that performed 3 and 4 divisions respectively, whereas 311 (n = 5) and 64 (n = 5) CFCs were generated by 1000 cells cultured without MS5 cells. Interestingly, MS5 cells had no detectable effect on the LTC-IC activity of cells that divided only twice in 4 days-1606 CFCs (n = 6) and 1993 (n = 6) CFCs, respectively, without and with MS5 cells-and a 48 additional hours of coculture were necessary to unmask changes in the LTC-IC activity mediated by stromal cells. These results indicate that cytokines and stroma-derived signals can regulate independently the proliferation and differentiation of primitive cells and that these stroma-derived extracellular factors act directly on their target cells.
Bennaceur-Griscelli
A
A
INSERM U 362, Institut Gustave Roussy, Villejuif, and INSERM U 474, Hôpital Port Royal, Paris, France.
Pondarré
C
C
Schiavon
V
V
Vainchenker
W
W
Coulombel
L
L
D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D000818:Animals; D015703:Antigens, CD; D018952:Antigens, CD34 / Q000502:physiology*; D000943:Antigens, Differentiation; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D002450:Cell Communication; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D018920:Coculture Techniques; D003114:Colony-Forming Units Assay; D016207:Cytokines / Q000494:pharmacology*; D006801:Humans; D008562:Membrane Glycoproteins; D051379:Mice; D008938:Mitosis / Q000502:physiology; D009244:NAD+ Nucleosidase; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000276:immunology; D017154:Stromal Cells / Q000502:physiology*
D015703:Antigens, CD; D018952:Antigens, CD34; D000943:Antigens, Differentiation; D016207:Cytokines; D008562:Membrane Glycoproteins; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; C498155:Cd38 protein, mouse; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1