Transitional change of colony stimulating factor requirements for erythroid progenitors

Abstract

The course of the differentiation and proliferation of the human erythroid burst-forming units (BFU-E) to colony-forming units (CFU-E) was directly investigated using a combination of highly purified BFU-E, a liquid culture system, and the following clonal assay. Highly purified human blood BFU-E with a purity of 45-79% were cultured in liquid medium with recombinant human erythropoietin (rEP) and recombinant human interleukin-3 (rIL-3) to generate more differentiated erythroid progenitors. The cultured cells were collected daily for investigating the morphology, the increment in the number of cells and the clonality. Ninety percent of purified BFU-E required not only rEP but also rIL-3 for clonal development. By 7 days of liquid culture, the total cell number increased 237 +/- 20-fold above the starting cells, while erythroid progenitors increased 156 +/- 74-fold. As the incubation time in liquid culture increased, the cells continuously differentiated in morphology. Replating experiments with rEP combined with or without rIL-3 showed the following: 1) The number of erythroblasts that were part of erythroid colonies decreased with accompanying erythroid progenitor differentiation and proliferation. 2) As the incubation time in liquid culture increased, erythroid progenitors had a graded loss of their dependency on rIL-3 and a complete loss of dependency was observed after 3 days of liquid culture. At that time 85% of the erythroid progenitors gave rise to colonies of more than 100 erythroblasts which were equivalent to mature BFU-E. These studies provide a quantitative assessment of the loss of IL-3 dependency by BFU-E and indicate that the size of the generated erythroid colonies and their IL-3 requirement correlate with the erythroid differentiated state.

Establishment of normal, terminally differentiating mouse erythroid progenitors: molecular characterization by cDNA arrays

“…The figure depicts three of the six quadrants (A, B, and C) of the cDNA arrays, each consisting of 98 different cDNAs spotted in duplicate. An (incomplete) selection of spots with reduced intensity on differentiation is boxed with dashed rectangles (spots 1, 2, 3, 4, 8), whereas some differentiation‐induced signals are indicated by solid boxes (5, 6, 7, 9, 10). Examples of spots, the intensity of which remained constant during differentiation are marked by dashed ellipses.…”

A Novel Way to Induce Erythroid Progenitor Self Renewal: Cooperation of c-Kit with the Erythropoietin Receptor

“…In particular, both human and avian BFU-E behave like CFU-E if they are exposed to Epo/insulin in the absence of SCF. Their division potential before entering the CFU-E stage and their kinetics of terminal differentiation are drastically affected by the abundance of SCF as well as by multiple other factors (Beug et al, , 1996Muta et al, 1994Muta et al, , 1995Sawada et al, 1991;Wessely et al, 1997b;von Lindern et al, submitted). Therefore, these normal erythroid progenitors will be referred to as BFU-E/CFU-E.…”

“…According to a generally accepted model, the earliest erythroid progenitor is the burst forming unit erythroid (BFU-E). This cell retains the ability to migrate in semisolid medium (thus the 'burst-like' appearance of BFU-E colonies in semisolid medium), is dependent on both erythropoietin (Epo) and the c-Kit ligand stem cell factor (SCF) for proliferation and differentiation and has a capacity of undergoing up to 10 cell divisions until terminal differentiation Sawada et al, 1991). In contrast, the more mature colony forming unit erythroid (CFU-E) is unresponsive to SCF, forms small, compact colonies in the presence of Epo plus insulin and undergoes terminal differentiation after 4 -5 rapid cell divisions (Sawada et al, 1987(Sawada et al, , 1989.…”

Effects of glucocorticoids and mineralocorticoids on proliferation and maturation of human peripheral blood stem cells

“…To maintain a balanced composition of hematopoietic cells, progenitor cells have to regulate proliferation and differentiation. Hematopoietic progenitor cells generate a large number of differentiated progenitors [17]. GC inhibit the formation of murine granulocyte-macrophage (GM) colonies [18], but enhance the formation of erythroid colonies in vitro [19][20][21].…”