A self‐renewing, bipotential erythroid/mast cell progenitor in continuous cultures of normal murine bone marrow

Abstract

We have established permanent lines of nonadherent cells from fresh normal mouse bone marrow in media containing pokeweed mitogen-stimulated spleen cell conditioned medium (PWSCM). These lines continuously produced erythropoietic progenitor cells (detected by their ability to form erythroid bursts in semi-solid medium containing erythropoietin) together with cells having characteristics of the mast cell lineage (as demonstrated by metachromatic staining with toluidine blue, histamine content and membrane receptors for IgE). Sixteen such cell lines have been established in sixteen attempts. Cloning experiments were carried out to determine the nature of the progenitor cell(s) responsible for the permanence of these cultures. When cells were cultured in methylcellulose medium containing PWSCM, colonies were observed which reached macroscopic size after 4 weeks of incubation. Replating of individual primary colonies resulted in secondary colony formation, indicating the presence of progenitor cells with self-renewal potential. Forty-seven primary colonies were picked and their cells were suspended in liquid culture medium containing PWSCM. Of these, twenty-one could be expanded to establish permanently growing sublines. Sixteen of these sublines were found to be composed of both erythroid progenitors and mast cells. In five sublines only mast cells could be seen; none of the sublines appeared to be purely erythroid. Karyotypic analysis of mast cells and of erythroid cells of seven sublines derived from individual colonies which arose in cocultures of male and female cells revealed that the mast cells and erythroid cells were both of the same sex in each of the seven sublines; this demonstrates the single cell origin of each colony and of the two lineages derived from it. We conclude that these nonadherent, factor-dependent cell lines are maintained by self-renewal and differentiation of bipotential progenitor cells apparently restricted to the erythroid and mast cell lineages.

bcr-abl, the hallmark of chronic myeloid leukaemia in man, induces multiple haemopoietic neoplasms in mice.

“…Intriguingly, the re-established line also expressed GM-CSF and M-CSF RNA, unlike the parental line ( Figure 5). We conclude that the cell transformed by bcr-abl virus in each of these examples was a progenitor or stem cell with capacity to differentiate into both erythroid and mast cell lineages, perhaps the self-renewing bipotential erythroid/mast cell progenitor characterized by Wendling et al (1985). RCS tumours can derive from a progenitor which also displays erythroid and/or mast cell potential.…”

GATA-1 but not SCL induces megakaryocytic differentiation in an early myeloid line.

“…Alternatively, GATA-1 may lie upstream of SCL in the hematopoietic regulatory hierarchy. Lineage relationships among hematopoietic progenitor cell types are not firmly established, but progenitor cell assays point to a close association between the erythroid, mast cell and megakaryocytic lineages (Wendling et al, 1985;Nishi et al, 1990), and certain tumor cell lines can differentiate along two or all three of these lineages (Elefanty and Cory, 1992). Thus GATA-1 expression probably initiates within a common progenitor for all three lineages.…”

Brain mast cell relationship to neurovasculature during development

“…Pia-The pial mast cell expands during the period from birth through PN11. The source of mast cells in the pia, as elsewhere, is likely to be from the circulating precursors derived from the bone marrow (Wendling et al, 1985). Committed mast cell progenitors circulate in the blood (Kitamura et al, 1979;Rodewald et al, 1996) and differentiate upon entering into tissues and organs (Kitamura et al, 1987).…”