Clonal analysis of proliferation and differentiation of paired daughter cells: action of granulocyte-macrophage colony-stimulating factor on granulocyte-macrophage precursors.

Abstract

Mouse granulocyte-macrophage progenitor cells were stimulated to divide by the granulocyte-macrophage colony-stimulating factor (GM-CSF). The two daughter celis were separated; one daughter was transferred to medium containing a high concentration of GM-CSF, the other to medium containing a low concentration. Daughter cell-derived clones in the presence of 2500 units of GM-SF had average cell cycle times 3.5 + 2.5 (SEM) hr shorter than clones derived from the paired daughter cell stimulated by 50 units of GM-CSF. Final colony size achieved after stimulation by 50 units of GM-CSF was always smaller than that of colonies stimulated by 2500 units of GM-CSF. In 8 of 41 instances, colonies stimulated by 50 units of GM-CSF developed, or were composed only of, macrophage populations in contrast to the granulocytic composition of colonies derived from the paired daughter cell growing in the presence of 2500 units of GM-CSF. The regulator GM-CSF appears able to directly influence cell cycle times and the pathway of differentiation entered by many bipotential granulocyte-macrophage precursor cells.In the presence of adequate concentrations of the specific regulator, granulocyte-macrophage colony-stimulating factor (GM-CSF), the progenitors of granulocytes and macrophages are stimulated to proliferate in vitro to form colonies of differentiating granulocytes or macrophages or both (1). Single-cell cloning studies indicated that many progenitor cells are bipotential and are able to form both granulocyte and macrophage progeny (2, 3). In the presence of high regulator concentrations, even with GM-CSF purified to homogeneity, a high proportion of granulocytic colonies develops whereas in the presence of very low concentrations, only macrophage colonies develop (1,4,5). A relationship has also been observed between GM-CSF concentration and the rate of proliferation of developing colony cells (6). These observations suggested that GM-CSF is able to shorten cell cycle times of proliferating granulocyte-macrophage cells and to determine whether progeny cells exhibit granulocyte or macrophage differentiation.Interpretation of these data has been complicated by the demonstration of heterogeneity among granulocyte-macrophage progenitor cells (7,8). Subsets of precursors exist that appear to be preprogrammed to form only granulocytic progeny and to require high concentrations of GM-CSF for stimulation. Conversely, subsets of granulocyte-macrophage progenitors appear able to form only macrophage progeny and to respond to stimulation by low GM-CSF concentrations. It might be, therefore, that GM-CSF merely selectively activates differing subsets of preprogrammed progenitor cells without having any significant capacity to influence the number or type of progeny produced.The present experiments using paired daughter cells of in-The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this...

Thrombopoietin responsiveness reflects the number of doublings undergone by megakaryocyte progenitors

“…The solid line represents the TPO threshold distribution for the total MK progenitor population. The 95% confidence intervals (95% CIs) of TPO50 were 2.68 to 9.04 pg/mL (total MK), 0.62 to 2.55 pg/mL (1 MK), 3.36 to 9.32 pg/mL (2 MKs), 13 In view of the association between high responsiveness and loss of proliferative potential, a comparison was made of the CD34 ϩ CD41 ϩ CD42a ϩ and CD34 ϩ CD41 ϩ CD42a Ϫ fractions separated by cell sorting from the CD34 ϩ CD41 ϩ megakaryocyte progenitor population. Figure 6 (left panel) shows that compared with the CD42a Ϫ fraction, the CD42a ϩ fraction was shifted toward the generation of smaller-sized clones (chi-square ϭ 108, P Ͻ .001) and produced twice as many single megakaryocyte clones (64% versus 33%).…”

“…The effects of stimulators of hematopoiesis are mediated by suppression of apoptosis and promotion of survival, [43][44][45][46][47][48] shortening of the cell cycle, 13,49,50 and retardation of differentiation. 50 The results described in the present investigation suggest that recruitment provides an additional mechanism of response to stimulators.…”

“…In fact, data demonstrate that CFU-MKs determine in part the amplification of their progeny and, therefore, impart a degree of homogeneity to this progeny. 12 In the granulocyte-macrophage series, the squared correlation coefficient of approximately 0.50 in NbD achieved by each of paired granulocyte-macrophage colonyforming unit (CFU-GM) daughter cells, which can be calculated from the data of Metcalf,13 indicates that one half of the total variance in NbD undergone by CFU-GM is related to preexisting, heritable characteristics of the progenitor cells. Thus, evidence of synchronization in whole clones implies that the commitment event is not random among the progeny of the colony-forming cell.…”

Dual Role of GM-CSF as a Pro-Inflammatory and a Regulatory Cytokine: Implications for Immune Therapy

“…While GM-CSF can cause granulocyte lineage commitment at higher concentrations, it can cause monocyte lineage commitment (Metcalf 1980) at lower concentrations. Therefore, it is suggested that not only GM-CSF induces differentiation of specific myeloid cell types but also selectively guides the differentiation of a common progenitor along the granulocyte, macrophage, and DC development pathways in a concentration-dependent manner.…”

Retrovirus mediated transfer and expression of GM-CSF in haematopoietic cells

“…The haematopoietic growth factor GM-CSF can maintain the survival of relatively primitive multipotential cells (Metcalf et al, , 1986 and is capable of directing the differentiation of progenitor cells down the granulocyte and macrophage lineages (Metcalf, 1980). Although the expression of GM-CSF is not detected in normal myeloid cells, GM-CSF mRNA and activity has been detected in the haematopoietic tissue from a number of patients with acute myeloid leukaemia (AML) (Young & Griffin, 1986;Young et al, 1987).…”