OBJECTIVE: The aim of this study was to determine whether the combination of a sizable generation of colony-forming cells (CFC) with the maintenance of their progenitors (pre-CFC) ensured by incubation in hypoxia is associated with a certain degree of cell cycling, ultimately responsible for "self-renewal" of pre-CFC. The effects of interleukin-3 (IL-3) on the cycling and CFC-generation potential of pre-CFC also was investigated. MATERIALS AND METHODS: In severely hypoxic (0.9% O(2)) murine bone marrow cell cultures containing stem cell factor, interleukin-6, and granulocyte colony-stimulating factor, pre-CFC maintenance was characterized by the culture-repopulating ability assay, an in vitro analogue of the marrow-repopulating ability assay. The proliferative history of CD34(+) cells in primary cultures was determined by PKH2 staining and related to their CFC-generation potential. In some experiments, subsets of CD34(+) cells sorted on the basis of the number of cell divisions (0, 1, >1) were independently characterized. RESULTS: In hypoxia, the numbers of CFC and CD34(+) cells were markedly reduced, whereas pre-CFC were maintained better than in air. Addition of 5-fluorouracil to hypoxic cultures for 2 days suppressed their CFC-generation potential. The CFC-generation potential of divided CD34(+) cells was maintained or increased with respect to that of undivided cells in hypoxia but not in air. IL-3 decreased CFC-generation potential at both oxygen concentrations. IL-3 also increased the number of CD34(+) cells that divided more than once in hypoxia, decreasing their CFC-generation potential. CONCLUSIONS: Maintenance of CFC-generation potential in hypoxia occurs mainly in a subset of cycling progenitors, despite their proliferation (self-renewal). IL-3 decreased CFC-generation potential by increasing the rate of pre-CFC proliferation beyond the first cycle, which probably results in their differentiation and loss of CFC-generation potential.
OBJECTIVE: The aim of this study was to determine whether the combination of a sizable generation of colony-forming cells (CFC) with the maintenance of their progenitors (pre-CFC) ensured by incubation in hypoxia is associated with a certain degree of cell cycling, ultimately responsible for "self-renewal" of pre-CFC. The effects of interleukin-3 (IL-3) on the cycling and CFC-generation potential of pre-CFC also was investigated. MATERIALS AND METHODS: In severely hypoxic (0.9% O(2)) murine bone marrow cell cultures containing stem cell factor, interleukin-6, and granulocyte colony-stimulating factor, pre-CFC maintenance was characterized by the culture-repopulating ability assay, an in vitro analogue of the marrow-repopulating ability assay. The proliferative history of CD34(+) cells in primary cultures was determined by PKH2 staining and related to their CFC-generation potential. In some experiments, subsets of CD34(+) cells sorted on the basis of the number of cell divisions (0, 1, >1) were independently characterized. RESULTS: In hypoxia, the numbers of CFC and CD34(+) cells were markedly reduced, whereas pre-CFC were maintained better than in air. Addition of 5-fluorouracil to hypoxic cultures for 2 days suppressed their CFC-generation potential. The CFC-generation potential of divided CD34(+) cells was maintained or increased with respect to that of undivided cells in hypoxia but not in air. IL-3 decreased CFC-generation potential at both oxygen concentrations. IL-3 also increased the number of CD34(+) cells that divided more than once in hypoxia, decreasing their CFC-generation potential. CONCLUSIONS: Maintenance of CFC-generation potential in hypoxia occurs mainly in a subset of cycling progenitors, despite their proliferation (self-renewal). IL-3 decreased CFC-generation potential by increasing the rate of pre-CFC proliferation beyond the first cycle, which probably results in their differentiation and loss of CFC-generation potential.
Authors: A V Guitart; C Debeissat; F Hermitte; A Villacreces; Z Ivanovic; H Boeuf; V Praloran Journal: Cell Death Differ Date: 2010-07-30 Impact factor: 15.828
Authors: E Del Poggetto; M Tanturli; N Ben-Califa; A Gozzini; I Tusa; G Cheloni; I Marzi; M G Cipolleschi; Y Kashman; D Neumann; E Rovida; P Dello Sbarba Journal: Cell Cycle Date: 2015 Impact factor: 4.534
Authors: Joan D Beckman; John D Belcher; Julie V Vineyard; Chunsheng Chen; Julia Nguyen; M Osita Nwaneri; M Gerard O'Sullivan; Evin Gulbahce; Robert P Hebbel; Gregory M Vercellotti Journal: Am J Physiol Heart Circ Physiol Date: 2009-07-17 Impact factor: 4.733