Growth and Differentiation of Human Stem Cell Factor/Erythropoietin-Dependent Erythroid Progenitor Cells In Vitro

Blood ◽  
1998 ◽  
Vol 92 (10) ◽  
pp. 3658-3668 ◽  
Author(s):  
Birgit Panzenböck ◽  
Petr Bartunek ◽  
Markus Y. Mapara ◽  
Martin Zenke

Abstract Stem cell factor (SCF) and erythropoietin (Epo) effectively support erythroid cell development in vivo and in vitro. We have studied here an SCF/Epo-dependent erythroid progenitor cell from cord blood that can be efficiently amplified in liquid culture to large cell numbers in the presence of SCF, Epo, insulin-like growth factor-1 (IGF-1), dexamethasone, and estrogen. Additionally, by changing the culture conditions and by administration of Epo plus insulin, such progenitor cells effectively undergo terminal differentiation in culture and thereby faithfully recapitulate erythroid cell differentiation in vitro. This SCF/Epo-dependent erythroid progenitor is also present in CD34+ peripheral blood stem cells and human bone marrow and can be isolated, amplified, and differentiated in vitro under the same conditions. Thus, highly homogenous populations of SCF/Epo-dependent erythroid progenitors can be obtained in large cell numbers that are most suitable for further biochemical and molecular studies. We demonstrate that such cells express the recently identified adapter protein p62dok that is involved in signaling downstream of the c-kit/SCF receptor. Additionally, cells express the cyclin-dependent kinase (CDK) inhibitors p21cip1 and p27kip1 that are highly induced when cells differentiate. Thus, the in vitro system described allows the study of molecules and signaling pathways involved in proliferation or differentiation of human erythroid cells.

Blood ◽  
1998 ◽  
Vol 92 (10) ◽  
pp. 3658-3668 ◽  
Author(s):  
Birgit Panzenböck ◽  
Petr Bartunek ◽  
Markus Y. Mapara ◽  
Martin Zenke

Stem cell factor (SCF) and erythropoietin (Epo) effectively support erythroid cell development in vivo and in vitro. We have studied here an SCF/Epo-dependent erythroid progenitor cell from cord blood that can be efficiently amplified in liquid culture to large cell numbers in the presence of SCF, Epo, insulin-like growth factor-1 (IGF-1), dexamethasone, and estrogen. Additionally, by changing the culture conditions and by administration of Epo plus insulin, such progenitor cells effectively undergo terminal differentiation in culture and thereby faithfully recapitulate erythroid cell differentiation in vitro. This SCF/Epo-dependent erythroid progenitor is also present in CD34+ peripheral blood stem cells and human bone marrow and can be isolated, amplified, and differentiated in vitro under the same conditions. Thus, highly homogenous populations of SCF/Epo-dependent erythroid progenitors can be obtained in large cell numbers that are most suitable for further biochemical and molecular studies. We demonstrate that such cells express the recently identified adapter protein p62dok that is involved in signaling downstream of the c-kit/SCF receptor. Additionally, cells express the cyclin-dependent kinase (CDK) inhibitors p21cip1 and p27kip1 that are highly induced when cells differentiate. Thus, the in vitro system described allows the study of molecules and signaling pathways involved in proliferation or differentiation of human erythroid cells.


Blood ◽  
1991 ◽  
Vol 78 (10) ◽  
pp. 2493-2497 ◽  
Author(s):  
CH Dai ◽  
SB Krantz ◽  
KM Zsebo

Abstract To understand the factors that regulate the early growth and development of immature erythroid progenitor cells, the burst-forming units-erythroid (BFU-E), it is necessary to have both highly purified target cells and a medium free of serum. When highly purified human blood BFU-E were cultured in a serum-free medium adequate for the growth of later erythroid progenitors, BFU-E would not grow even with the addition of recombinant human interleukin-3 (rIL-3), known to be essential for these cells. However, the addition of recombinant human stem cell factor (rSCF), which supports germ cell and pluripotential stem cell growth, stimulated BFU-E to grow equally well in serum-free as in serum-containing medium. Limiting dilution studies showed that rSCF acts directly on the BFU-E that do not require accessory cells for growth. Furthermore, rSCF was necessary for BFU-E development during the initial 7 days of culture, until these cells reached the stage of the late progenitors, the colony-forming units-erythroid (CFU-E). These studies indicate that early erythropoiesis is dependent on the direct action of SCF that not only affects early stem cells but is continually necessary for the further development of committed erythroid progenitor cells until the CFU-E stage of maturation.


Blood ◽  
1991 ◽  
Vol 78 (10) ◽  
pp. 2493-2497 ◽  
Author(s):  
CH Dai ◽  
SB Krantz ◽  
KM Zsebo

To understand the factors that regulate the early growth and development of immature erythroid progenitor cells, the burst-forming units-erythroid (BFU-E), it is necessary to have both highly purified target cells and a medium free of serum. When highly purified human blood BFU-E were cultured in a serum-free medium adequate for the growth of later erythroid progenitors, BFU-E would not grow even with the addition of recombinant human interleukin-3 (rIL-3), known to be essential for these cells. However, the addition of recombinant human stem cell factor (rSCF), which supports germ cell and pluripotential stem cell growth, stimulated BFU-E to grow equally well in serum-free as in serum-containing medium. Limiting dilution studies showed that rSCF acts directly on the BFU-E that do not require accessory cells for growth. Furthermore, rSCF was necessary for BFU-E development during the initial 7 days of culture, until these cells reached the stage of the late progenitors, the colony-forming units-erythroid (CFU-E). These studies indicate that early erythropoiesis is dependent on the direct action of SCF that not only affects early stem cells but is continually necessary for the further development of committed erythroid progenitor cells until the CFU-E stage of maturation.


1995 ◽  
Vol 15 (6) ◽  
pp. 3147-3153 ◽  
Author(s):  
G A Blobel ◽  
C A Sieff ◽  
S H Orkin

High-dose estrogen administration induces anemia in mammals. In chickens, estrogens stimulate outgrowth of bone marrow-derived erythroid progenitor cells and delay their maturation. This delay is associated with down-regulation of many erythroid cell-specific genes, including alpha- and beta-globin, band 3, band 4.1, and the erythroid cell-specific histone H5. We show here that estrogens also reduce the number of erythroid progenitor cells in primary human bone marrow cultures. To address potential mechanisms by which estrogens suppress erythropoiesis, we have examined their effects on GATA-1, an erythroid transcription factor that participates in the regulation of the majority of erythroid cell-specific genes and is necessary for full maturation of erythrocytes. We demonstrate that the transcriptional activity of GATA-1 is strongly repressed by the estrogen receptor (ER) in a ligand-dependent manner and that this repression is reversible in the presence of 4-hydroxytamoxifen. ER-mediated repression of GATA-1 activity occurs on an artificial promoter containing a single GATA-binding site, as well as in the context of an intact promoter which is normally regulated by GATA-1. GATA-1 and ER bind to each other in vitro in the absence of DNA. In coimmunoprecipitation experiments using transfected COS cells, GATA-1 and ER associate in a ligand-dependent manner. Mapping experiments indicate that GATA-1 and the ER form at least two contacts, which involve the finger region and the N-terminal activation domain of GATA-1. We speculate that estrogens exert effects on erythropoiesis by modulating GATA-1 activity through protein-protein interaction with the ER. Interference with GATA-binding proteins may be one mechanism by which steroid hormones modulate cellular differentiation.


Blood ◽  
1995 ◽  
Vol 86 (12) ◽  
pp. 4674-4680 ◽  
Author(s):  
P Mauch ◽  
C Lamont ◽  
TY Neben ◽  
C Quinto ◽  
SJ Goldman ◽  
...  

Peripheral blood stem cells and progenitor cells, collected during recovery from exposure to cytotoxic agents or after cytokine administration, are being increasingly used in clinical bone marrow transplantation. To determine factors important for mobilization of both primitive stem cells and progenitor cells to the blood, we studied the blood and splenic and marrow compartments of intact and splenectomized mice after administration of recombinant human interleukin-11 (rhlL-11), recombinant rat stem cell factor (rrSCF), and IL-11 + SCF. IL-11 administration increased the number of spleen colony- forming units (CFU-S) in both the spleen and blood, but did not increase blood long-term marrow-repopulating ability (LTRA) in intact or splenectomized mice. SCF administration increased the number of CFU- S in both the spleen and blood and did not increase the blood or splenic LTRA of intact mice, but did increase blood LTRA to normal marrow levels in splenectomized mice. The combination of lL-11 + SCF syngeristically enhanced mobilization of long-term marrow-repopulating cells from the marrow to the spleen of intact mice and from the marrow to the blood of splenectomized mice. These data, combined with those of prior studies showing granulocyte colony-stimulating factor mobilization of long-term marrow repopulating cells from the marrow to the blood of mice with intact spleens, suggest different cytokine- induced pathways for mobilization of primitive stem cells.


Blood ◽  
1995 ◽  
Vol 86 (2) ◽  
pp. 572-580 ◽  
Author(s):  
K Muta ◽  
SB Krantz ◽  
MC Bondurant ◽  
CH Dai

Stem cell factor (SCF), the ligand for the c-kit tyrosine kinase receptor, markedly stimulates the accumulation of erythroid progenitor cells in vitro. We now report that SCF delays erythroid differentiation among the progeny of individual erythroid progenitors while greatly increasing the proliferation of these progeny. These effects appear to be independent of an effect on maintenance of cell viability. Highly purified day-6 erythroid colony-forming cells (ECFC), consisting mainly of colony-forming units-erythroid (CFU-E), were generated from human peripheral blood burst-forming units-erythroid (BFU-E). Addition of SCF to the ECFC in serum-free liquid culture, together with erythropoietin (EP) and insulin-like growth factor 1 (IGF-1), resulted in a marked increase in DNA synthesis, associated with a delayed peak in cellular benzidine positivity and a delayed incorporation of 59Fe into hemoglobin compared with cultures without SCF. In the presence of SCF, the number of ECFC was greatly expanded during this culture period, and total production of benzidine-positive cells plus hemoglobin synthesis were ultimately increased. To determine the effect of SCF on individual ECFC, single-cell cultures were performed in both semisolid and liquid media. These cultures demonstrated that SCF, in the presence of EP and IGF-1, acted on single cells and their descendants to delay erythroid differentiation while substantially stimulating cellular proliferation, without an enhancement of viability of the initial cells. This was also evident when the effect of SCF was determined using clones of ECFC derived from single BFU-E. Our experiments demonstrate that SCF acts on individual day-6 ECFC to retard erythroid differentiation while simultaneously providing enhanced proliferation by a process apparently independent of an effect on cell viability or programmed cell death.


Blood ◽  
1996 ◽  
Vol 87 (10) ◽  
pp. 4100-4108 ◽  
Author(s):  
N Okumura ◽  
K Tsuji ◽  
Y Ebihara ◽  
I Tanaka ◽  
N Sawai ◽  
...  

We investigated the effects of stem cell factor (SCF) on the migration of murine bone marrow hematopoietic progenitor cells (HPC) in vitro using a modification of the checkerboard assay. Chemotactic and chemokinetic activities of SCF on HPC were evaluated by the numbers of HPC migrated on positive and negative gradients of SCF, respectively. On both positive and negative gradients of SCF, HPC began to migrate after 4 hours incubation, and their numbers then increased time- dependently. These results indicated that SCF functions as a chemotactic and chemokinetic agent for HPC. Analysis of types of colonies derived from the migrated HPC showed that SCF had chemotactic and chemokinetic effects on all types of HPC. When migrating activities of other cytokines were examined, interleukin (IL)-3 and IL-11 also affected the migration of HPC, but the degrees of each effect were lower than that of SCF. The results of the present study demonstrated that SCF is one of the most potent chemotactic and chemokinetic factors for HPC and suggest that SCF may play an important role in the flow of HPC into bone marrow where stromal cells constitutively produce SCF.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2175-2175
Author(s):  
Amittha Wickrema ◽  
Uddin Shahab ◽  
Jeong Ah-Kang ◽  
Ying Zhou ◽  
Koen van Besien ◽  
...  

Abstract Erythropoietin (Epo) and stem cell factor (SCF) guide erythroid cell maturation by exerting their effects at various stages of differentiation. Distinct and overlapping functions of these two growth factors have been well characterized. However, signaling pathways responsible for the antiapoptotic function of Epo and the proliferative function of SCF has not been fully characterized. Especially activation of common upstream signaling elements PI3-kinase, Akt kinase and phosphorylation/inactivation of forkhead transcription factors by both Epo and SCF bring about distinct functional outcomes have not been understood. In the present study we examined the activation of p70S6/mTOR pathway by Epo and SCF in CD34-derived primary erythroid progenitors. Our results provide evidence for activation of p70S6 kinase and mTOR by SCF but not by Epo or IGF-1 (insulin-like growth factor-1). We also show that only SCF phosphorylates protein translational regulatory proteins, 4E-BP1 and S6 ribosomal protein suggesting its involvement in promoting protein translation. Furthermore, we demonstrate that inhibition of mTOR by rapamycin results in reduction in erythroid cell proliferation and colony-formation under steady state culture conditions demonstrating the involvement of downstream signaling elements in the PI3/Akt kinase pathway in cell proliferation apart from its antiapoptotic signal. The reduction of both BFU-E and CFU-GM colony formation indicated that rapamycin also affects early hematopoietic cells. Examination of a parallel pathway involving signaling element Mnk1 showed that both Mnk1 and its downstream target eIF4E are not phosphorylated in response to SCF or Epo. However, these protein were constitutively phosphorylated in primary erythroid progenitors. Interestingly, we also found that during the proliferative phase of erythroid differentiation mTOR is mostly detected in the cytoplasmic fraction of the cells whereas during terminal phase of differentiation mTOR is detected in the nuclear fraction. These results suggest that mTOR may have additional functions associated with chromatin remodeling in erythroid progenitors, which occur prior to enucleation. Taken together, our data provide a mechanism for how distinct functions of Epo and SCF are accomplished through selective use of a common signaling pathway explaining in part how functional diversity is acheived.


Blood ◽  
1992 ◽  
Vol 80 (12) ◽  
pp. 3000-3008
Author(s):  
BP Alter ◽  
ME Knobloch ◽  
L He ◽  
AP Gillio ◽  
RJ O'Reilly ◽  
...  

Stem cell factor (SCF) enhances normal hematopoiesis. We examined its effect in vitro on bone marrow and blood progenitors from patients with inherited bone marrow failure syndromes, including 17 patients each with Diamond-Blackfan anemia (DBA) and Fanconi's anemia (FA), 3 with dyskeratosis congenita (DC), and 1 each with amegakaryocytic thrombocytopenia (amega) and transient erythroblastopenia of childhood (TEC). Mononuclear cells were cultured with erythropoietin (Ep) alone or combined with SCF or other factors. SCF increased the growth of erythroid progenitors in cultures from 50% of normal controls, 90% of DBA, 70% of FA, 30% of DC, and the amega and TEC patients; normal numbers were reached in 25% of DBA studies. Improved in vitro erythropoiesis with SCF in all types of inherited marrow failure syndromes does not suggest a common defect involving kit or SCF, but implies that SCF may be helpful in the treatment of hematopoietic defects of varied etiologies.


Blood ◽  
1993 ◽  
Vol 81 (10) ◽  
pp. 2591-2599 ◽  
Author(s):  
RS Weinberg ◽  
JC Thomson ◽  
R Lao ◽  
G Chen ◽  
BP Alter

A two-phase liquid-culture system was used to substantially amplify and differentiate erythroblasts, starting with mononuclear cells from the blood of normal adults, newborn infants, and patients with sickle cell anemia. After the first 7 days (phase 1), in medium plus fetal bovine serum (FBS) alone, or in combination with stem cell factor (SCF) or conditioned medium (CM), the cell number was unchanged, and the cells all looked like lymphocytes. These cells were then diluted into medium with erythropoietin (Ep) alone, with Ep and either SCF or CM, or in methylcellulose with the same factors (phase 2). After 14 days in liquid phase 2 with SCF and Ep, the cell numbers increased an average of 30-fold in the sickle, 24-fold in the newborn, and 4-fold in the normal adult cultures; almost all the cells were erythroblasts and erythrocytes. SCF in phase 1 increased the number of late progenitors (CFU-E) assayed in methylcellulose, with the largest number in sickle, followed by newborn cultures and then adult cultures. We conclude that erythroid progenitor cells survive for at least 7 days without Ep (but with FBS). Progenitor cells are amplified, particularly with SCF. Later in culture, SCF with Ep increases the final number of differentiated erythroid cells. Both the early and the late effects of SCF are most effective in sickle, followed by newborn cultures and then adult cultures.


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