Cell cycle distribution of cord blood-derived haematopoietic progenitor cells and their recruitment into the S-phase of the cell cycle.
The objective of this study was to evaluate the cycling status of cord blood (CB)-derived colony-forming cells (CFC) and long-term culture-initiating cells (LTC-IC), and their recruitment into the S-phase of the cell cycle. By using the cytosine arabinoside (Ara-C) suicide approach, we found that only small proportions of both CFC and LTC-IC were in the S-phase of the cell cycle. These estimates were confirmed by flow cytometric DNA analysis, which showed that 96 +/- 2% of CB-derived CD34+ cells were in G0/G1 and only 1.6 +/- 0.4% in the S-phase. Staining of CD34+ cells with an antistatin monoclonal antibody, a marker of the G0 phase, indicated that among CD34+ cells with a flow cytometric DNA content typical of the G0/G1 phase 68 +/- 7% of cells were in the G0 phase of the cell cycle. Incubation (24 h) with interleukin 3 (IL-3), recombinant human stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF) significantly increased the proportion of cells in the S-phase for both CFC and LTC-IC without inducing any loss in numbers. Flow cytometric DNA analysis also showed an increase in CD34+ cells in the S-phase upon continuous exposure to these cytokines. Our findings indicate that: (i) very few CB-derived CFC or LTC-IC were in the S-phase of the cell cycle; (ii) a substantial amount of CD34+ cells with a flow cytometric DNA content typical of the G0/G1 fraction was cycling, as found in the G1 phase of the cell cycle; and (iii) 24-h incubation with IL-3, SCF and G-CSF could drive a proportion of progenitor cells into the S-phase without reducing their number. These data might be useful for gene transfer protocols and the ex vivo expansion of CB-derived progenitor cells.
Lucotti
C
C
Department of Internal Medicine and Medical Therapy, University of Pavia School of Medicine, Pavia, Italy.
Malabarba
L
L
Rosti
V
V
Bergamaschi
G
G
Danova
M
M
Invernizzi
R
R
Pecci
A
A
Ramajoli
I
I
Perotti
C
C
Torretta
L
L
De Amici
M
M
Salvaneschi
L
L
Cazzola
M
M
D018952:Antigens, CD34 / Q000276:immunology; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins; D002478:Cells, Cultured; D005312:Fetal Blood / Q000166:cytology* / Q000276:immunology; D005434:Flow Cytometry; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D020648:Peptide Elongation Factor 1; D011506:Proteins / Q000032:analysis; D011994:Recombinant Proteins; D016196:S Phase; D019089:Stem Cell Factor / Q000494:pharmacology
D018952:Antigens, CD34; D018797:Cell Cycle Proteins; C503234:EEF1A2 protein, human; D007377:Interleukin-3; D020648:Peptide Elongation Factor 1; D011506:Proteins; D011994:Recombinant Proteins; D019089:Stem Cell Factor; D016179:Granulocyte Colony-Stimulating Factor