SEARCH · Search PubMed
Results for “Erythroid Precursor Cells”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
[Formation of erythroid colonies of bone marrow cells and their sensitivity to erythropoietin (EP) (in vitro) in piglets during the early postnatal period].
Collected at the first hours (0, 6, 12, 24, 48) and days (3 and 5) of piglets life bone marrow was cultured (in vitro) during 48 and 72 hours in order to assess the efficiency of development and ability of isolated marrow cells to form erythroid colonies (CFU-E-Colony Forming Unit) and also to examine the erythroidal sensitivity to Ep addition. It was found that bone marrow of new born piglets shows high ability to form erythroid colonies (CFU-E), but low sensitivity to Ep (erythropoietin). The limited efficiency to form immature erythroid colonies following 12h as well as matured ones after 24h, has been also shown. Observed changes could be caused by the limited erythroidal cells sensitivity to Ep.
Induction of erythropoietin receptors during aclacinomycin-mediated erythroid differentiation of K562 leukemia cells.
Human K562 leukemia cells have been induced to differentiate along the erythroid lineage by aclacinomycin (ACM), an anthracyclic antitumor drug. During differentiation over 3 days in culture, the expression and the nature of erythropoietin (EPO) receptors have been analyzed using 125I-labeled bioactive recombinant human EPO. Aclacinomycin at 20 nM, the concentration inducing optimum differentiation, progressively increased EPO-specific binding. On day 3, EPO binding was nine-fold higher than that of the controls (1031 +/- 101 cpm/5 x 10(6) cells versus 112 +/- 15 cpm); with various concentrations of ACM, the increase in EPO binding appeared to parallel the recruitment of hemoglobin-producing cells. However, at 95% of growth inhibition, EPO binding remained constant while the percentage of differentiated cells decreased. Specific binding was reversible, saturable, and proportional to cell number; bound EPO was displaced by unlabeled EPO. Scatchard analysis of the equilibrium binding data suggested the existence of a single class of EPO receptors with an apparent Kd of 867 +/- 458 pM, corresponding to 400 +/- 142 receptors per cell. Affinity cross-linking of 125I-EPO using disuccinimidyl suberate followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions demonstrated that EPO was preferentially cross-linked to a protein of approximately 116 kD. Taken together, these results demonstrate that, in addition to cytostatic properties, antitumor drugs such as ACM can modulate the expression of differentiation factor receptors on the surface of leukemic cells.
The effects of transforming growth factor beta 3 on the growth of highly enriched hematopoietic progenitor cells derived from normal human bone marrow and peripheral blood.
The effects of transforming growth factor beta 3 (TGF-beta 3) on growth in semisolid cultures of enriched hematopoietic progenitors derived from normal human marrow and blood were evaluated. Conditioned media from the Mo-T cell line (MoCM) were the source of colony-stimulating factors used to optimally stimulate primitive progenitors. To assess whether a proportion of granulocyte/monocyte (GM) progenitors were prevented from cycling, all sizes of GM aggregates were evaluated from 3 to 20 days. The activity of TGF-beta 3 on the growth of erythroid burst-forming units (BFU-E) and granulocyte-macrophage colony-forming units (CFU-GM) was similar to that observed for TGF-beta 1. TGF-beta 3 (10, 100, and 1,000 pmol/liter), added initially or 72 h after initiation of culture, did not significantly affect the total number of marrow GM aggregates at 3, 7, 14, and 20 days, but TGF-beta 3 (1,000 pmol/liter), added initially, reduced the total number of blood GM aggregates. This suggests that some blood GM progenitors might be blocked from cycling but that the great majority of marrow GM progenitors are not blocked. Whether TGF-beta 3 (10, 100, and 1,000 pmol/liter) was added initially or after 72 h of stimulation by MoCM, there was a dose-dependent reduction of marrow and blood GM colony size even when the total number of colonies was unaffected. TGF-beta 3 (10, 100, and 1,000 pmol/liter), added initially or at 72 h, reduced in a dose-dependent manner the size of marrow and blood-derived BFU-E. TGF-beta 3 (1,000 pmol/liter) was more likely to reduce the total number of marrow and blood BFU-E, and this increased sensitivity of the erythroid lineage may prevent the development of this population in colonies derived from multipotential colony-forming unit-granulocyte/erythroid/monocyte (CFU-GEM). The results suggest that the main effect of TGF-beta 3 and TGF-beta 1 is to slow the rate of proliferation of hematopoietic progenitors rather than to prevent them from beginning proliferation. This results in a reduction in colony size which prevents the identification of primitive versus mature progenitor on the basis of standard criteria of colony size.
Influence of T-lymphocytes and lactoferrin on the survival-promoting effects of IL-1 and IL-6 on human bone marrow granulocyte-macrophage and erythroid progenitor cells.
Purified recombinant human (rhu) interleukin (IL)-1 alpha, rhuIL-6, iron saturated lactoferrin (LF), and T-lymphocytes were assessed for their effects on the survival of granulocyte-macrophage (granulocyte-macrophage colony-forming units, CFU-GM) and erythroid (erythroid burst-forming units, BFU-E) progenitor cells from human low-density (LD) and nonadherent LD T-lymphocyte-depleted (NALT-) bone marrow (BM) cells. Colony-stimulating factor (CSF) deprivation studies showed that 10 ng/ml IL-1 alpha could promote the survival of CFU-GM and BFU-E from NALT- BM cells. Concentrations of 1 ng/ml IL-1 alpha and 1-100 ng/ml IL-6 alone could not promote progenitor cell survival from NALT- BM cells; however, concentrations of 1 ng/ml each of IL-1 alpha and IL-6 could synergize to promote the survival of CFU-GM but not of BFU-E. The combination of these low concentrations of IL-1 alpha and IL-6 could, however, support the survival of BFU-E in the presence of purified T-lymphocytes. LF could decrease the survival of CFU-GM and BFU-E from LD but not from NALT- BM cells, apparently due to the inhibition of IL-1 release from monocytes in this cell population. The suppressive effect of LF on the survival of those progenitor cells was abolished by concentrations of 10 ng/ml IL-1 alpha or 1 ng/ml each of IL-1 alpha and IL-6. These results demonstrate that the survival of human marrow CFU-GM and BFU-E can be influenced by IL-1, IL-6, LF, and T-lymphocytes.
[Molecular biology of erythropoietin].
Explore the source record for details and available documents.
Granulocyte-macrophage colony-stimulating factor-dependent growth and erythropoietin-induced differentiation of a human cell line MB-02.
Peripheral blood blasts from a patient with acute megakaryoblastic leukemia were placed into liquid cultures with recombinant growth factors. Growth, but not differentiation, was supported by interleukin-3 (IL-3) or granulocyte-macrophage colony-stimulating factor (GM-CSF) for the first 30 days of culture. Sustained growth occurred only with GM-CSF and gave rise to the cell line MB-02, which has been in continuous culture for over 1 year. The cell line retained the surface phenotype of the leukemic megakaryoblasts except for the loss of glycoproteins Ib and IIb/IIIa, which were induced after exposure to phorbol esters. The induction of erythropoiesis occurred when GM-CSF-deprived cells were cultured with erythropoietin (Epo). Well-defined morphologic stages of differentiation ranging from primitive erythroblasts to nuclei-extruding normoblasts were seen. Transforming growth factor-beta inhibited GM-CSF- and Epo-dependent growth, but not erythroid maturation. Indirect immunofluorescence using globin chain-specific monoclonal antibodies detected fetal, but not adult hemoglobin in the uninduced cells. beta-globin was induced and gamma-globin was increased after Epo exposure. Both globin species accumulated in the developing erythrocytes until terminal differentiation. Quantitative S1 analysis of beta-like globin transcripts showed very low levels of epsilon- and beta-globin expression and high levels of gamma-globin expression in cells maintained in GM-CSF. Five days after induction with Epo, epsilon message decreased to barely detectable levels while gamma and beta transcripts increased threefold and 20-fold, respectively. This novel cell line not only retains many characteristics of the leukemic megakaryoblasts from which it was derived, but also can be induced to recapitulate apparent normal erythropoiesis.
Characterization of normal human bone marrow by flow cytometry.
Fifteen bone marrow samples were obtained from consenting donors for allogenic bone marrow transplantation and were studied by flow cytometry. The simultaneous analysis, cell by cell, of size (forward angle light scattering), structure (right angle light scattering) and surface antigenic expression with 20 monoclonal antibodies allowed selection of ten reproducible cell subsets which were sorted and studied by microscopic examination in order to confirm their distinct characteristics. This very accurate analysis of a bone marrow cytogram should find applications in view of a better characterization of normal and pathological human bone marrow.
Effect of leukaemic sera & cell-extracts on splenic colony counts (CFU-S).
Sera and leukaemic cell extracts from patients of acute leukaemia were evaluated for their effect on the repopulating ability of the pluripotent stem cells and erythroid differentiation by an in vivo splenic colony count (CFU-S) technique. Normal donor marrow cells of mice were treated with sera and cell extracts from patients of acute leukaemic and healthy controls and injected in the recipient mice. The CFU-S performed on the seventh day to assess repopulating ability of the stem cell showed consistently lower CFU-S counts in the test groups, with leukaemic sera (P less than 0.01) as well as leukaemic cell-extracts (P less than 0.001). The erythroid differentiation assessed by 59Fe uptake by the spleens also showed significantly reduced counts in the two test groups (P less than 0.01 and less than 0.001 respectively). The results indicate that both leukaemic sera and cell-extracts exert a significant suppressive effect on the repopulating ability of the stem cells and on their erythroid differentiation.
Expression of interleukin 6 and its specific receptor by untreated and PMA-stimulated human erythroid and megakaryocytic cell lines.
Different human hematopoietic cell lines were analyzed for the presence of interleukin 6 (IL-6) and IL-6 receptor (IL-6-R). Both IL-6 mRNA and secreted active IL-6 protein were detectable in untreated cell lines with erythroid or megakaryoblastic features (K562, HEL, KU 812, MEG-01, and Dami), but they were not expressed constitutively in other leukemic cell lines (KG1, HL60, and U937). IL-6-R production, studied by the presence of its mRNA and specific binding sites for iodinated recombinant IL-6, was detected in most cell lines except K562, HEL, and Dami. Therefore, only KU 812 and MEG-01 coexpress both IL-6 and IL-6-R. After phorbol ester myristate acetate (PMA) treatment, all the cell lines studied expressed or overexpressed IL-6. In the erythroid K562 cell line, IL-6-R was not detectable before induction, but was promptly expressed after stimulation with PMA, suggesting that some of the new features of K562 cells induced by PMA may be mediated by IL-6. However, neutralizing antibodies against IL-6 did not block either the growth arrest or the loss of the erythroid phenotype induced by PMA. The presence of IL-6 and IL-6-R in erythroid and megakaryocytic leukemic cell lines suggests that their synthesis may occur during normal hematopoietic differentiation.
In vitro differentiation and proliferation of human hematopoietic progenitors: the effects of interleukins 1 and 6 are indirectly mediated by production of granulocyte-macrophage colony-stimulating factor and interleukin 3.
The effect of recombinant human interleukin (IL)-1 and IL-6 on the differentiation and proliferation in vitro of human granulocyte-macrophage (GM) and erythroid progenitors has been investigated in either fetal bovine serum (FBS)-supplemented or FBS-deprived cultures. Sources of progenitor cells were unfractionated bone marrow cells or marrow cells depleted of adherent and/or T cells. Each interleukin was investigated either alone or in combination with GM-colony-stimulating factor (CSF), IL-3 and erythropoietin (Epo), or granulocyte (G)-CSF. In FBS-supplemented cultures of unfractionated marrow cells, IL-1 induced optimal GM colony growth and increased by 50% the number of erythroid bursts that formed in the presence of Epo. The addition to these cultures of a neutralizing anti-GM-CSF monoclonal antibody or of an anti-IL-3 serum decreased the growth of GM colonies by 80% and 40%, respectively. Under the same conditions, IL-6 had no effect on GM colony growth but increased by 90% the number of erythroid bursts. This effect was partially (40%) neutralized by addition of anti-IL-3 serum. IL-1 and IL-6 were weak stimuli, or had no effect at all, either alone or in combination with GM-CSF and IL-3 in FBS-deprived cultures or in FBS-supplemented cultures of nonadherent or nonadherent, T-cell-depleted marrow cells. IL-1 and IL-6 had no effect, either alone or in combination with IL-3, in maintaining the number of progenitor cells in short-term liquid suspension cultures. These results indicate that the actions of IL-1 and IL-6 on hematopoiesis are mainly indirect and mediated by the production of GM-CSF and/or IL-3 by accessory cells. However, neither IL-1 nor IL-6 alone is sufficient to stimulate production of growth factor(s) by accessory cells, and at least a second stimulus, provided by FBS, is also required. These data are in agreement with a multisignal model of regulation of the expression of growth factor genes.
Decrease in the number of progenitors of erythrocytes (BFUe, CFUe), granulocytes and macrophages (GM-CFC) in bone marrow of rats after a 14-day flight onboard the Cosmos-2044 Biosatellite.
A decrease in the number of progenitors of erythrocytes (BFUe, CFUe) and of granulocytes and macrophages (GM-CFC) in bone marrow was found in rats exposed to microgravitation during a 14-day flight onboard the Cosmos-2044 biosatellite when compared to control rats maintained under conditions of gravitation on the ground. The number of progenitors of both lineages of haemopoiesis was also decreased in synchronous control rats, thus suggesting that the pool of progenitors is influenced also by the action of the nonspecific space flight factors.
[Induction of micronuclei in polychromatic erythrocytes from mouse bone marrow following intraperitoneal administration of halogenated benzenes].
The mutagenicity of halogenated benzenes, including three isomers of tri- and tetrachlorobenzenes (TCB, TeCB) was studied on male Swiss CD1 mice by MN test. The data presented show that all the halogenated benzenes tested were found to be clastogenic apart from 1,2,3,5-TeCB. No significant differences were observed in the clastogenic activities of TCB-isomers and TeCB-isomers.
Kidney cell lysates contain an activity that stimulates mature erythroid burst-forming-unit (mBFU-E) proliferation.
This study reports the detection of an activity that stimulates the development of a subclass of burst-forming unit-erythroid (BFU-E) progenitors giving rise to small bursts in semi-solid cultures established in the presence of saturating concentrations of erythropoietin. These progenitors are considered to be mature BFU-E. The activity is found in extracts from kidney cells and appears to be physiologically regulated as it was respectively enhanced and decreased in kidneys from anemic and polycythemic mice. The disappearance of activity in kidney-cell extracts during long-term polycythemia correlated with an accumulation of mature BFU-E in the spleen and bone marrow of polycythemic mice. Using specific neutralizing antibodies and in vitro tests, we also show that this activity is different from hemopoietins known to share burst promoting activity (Interleukin-3 [IL-3], granulocyte-macrophage colony-stimulating factor [GM-CSF], Interleukin-4 [IL-4], erythropoietin [EPO], human interleukin for DA cells [HILDA]) and that it can stimulate erythroid differentiation in long term bone marrow cell cultures.
Detection and isolation of the erythropoietin receptor using biotinylated erythropoietin.
Procedures have been developed to label human erythropoietin (Ep) with biotin to detect and isolate the Ep-receptor. The labeling method used the abundant carbohydrate groups on Ep and resulted in biologically active biotin-Ep (b-Ep) containing 8 to 10 biotins per Ep molecule. Specific binding of b-Ep to cells from spleens of mice made anemic by phenylhydrazine injections was demonstrated using 125I-labeled streptavidin. B-Ep, together with fluorescently tagged streptavidin, was found to specifically detect Ep-receptor-bearing cells by flow cytometry. This was demonstrated in several ways. First, approximately 90% of nucleated spleen cells from phenylhydrazine-treated mice were clearly fluorescent after staining with b-Ep and streptavidin-phycoerythrin, whereas only background fluorescence was detected using spleen cells from untreated mice. In addition, Ep-receptors were detected on 5% to 10% of normal mouse bone marrow cells, and these cells could be identified as erythroid in nature by separating the cells into subpopulations based on light-scatter properties. Third, Ep-receptor expression was found to correlate positively with expression of transferrin receptors, confirming the erythroid nature of these cells. B-Ep was also used to isolate Ep-receptors from monkey COS cells transfected with the murine Ep-receptor cDNA. In these experiments a cell-surface-bound protein of approximately 65 Kd and an intracellular protein of approximately 60 Kd were isolated from these cells. The procedures described in this report for detecting Ep-receptor expressing cells and for isolating the Ep-receptor should be valuable for purifying erythroid cells from heterogeneous cell populations, for elucidating the structure of the Ep-receptor, and for studying the biological activities of Ep at the cellular and molecular level.
Differentiation kinetics and globin gene expression by circulating human BFUe in suspension cultures.
We studied the kinetics of erythroid differentiation and the globin synthetic patterns of circulating early erythroid progenitors (erythroid burst-forming units, BFUe) stimulated to differentiate in suspension cultures in the presence of interleukin 3 (IL-3) and erythropoietin. Erythroid progenitor cells present at the onset of culture and on successive days (2-12) thereafter were quantitatively assessed by clonal assays, whereas globin synthesis was measured sequentially in aliquots from the suspension culture. Although BFUe numbers increased to a peak value by day 4, the number of progenitors generating larger bursts was progressively decreasing with a concomitant increase in the number of smaller sized bursts. Erythroid colony-forming units (CFUe) and erythroid clusters were first detected by day 4 and peaked on day 6. Proerythroblasts were morphologically identifiable on day 4, and they progressively increased in number and maturity so that, at culture days 10 and 12, 51% and 59% of the culture cells were erythroblasts, respectively. In keeping with the morphologic changes during the liquid culture, globin mRNA was first detected on day 4. gamma/gamma + beta mRNA ratios were highest on days 4 and 6 and declined thereafter. Our results show that circulating BFUe (at least the majority of them) can differentiate and mature as a cohort in suspension cultures, providing terminal progeny with accelerated kinetics compared to semisolid, clonal cultures. In this system the same cohort of cells can be easily sampled throughout the culture for molecular studies on erythroid differentiation.
In vitro studies of erythropoietin-dependent regulation of erythropoiesis in myelodysplastic syndromes.
Erythropoietin-dependent regulation of erythropoiesis in myelodysplastic syndromes (MDS) was evaluated by measuring the in vitro response of primitive (BFU-E) and relatively mature (CFU-E) erythroid progenitors from 12 patients and from eight healthy donors to recombinant human erythropoietin (rhEPO), and by quantifying relationships between circulating EPO levels and progenitor cell frequencies in MDS marrow. Half-maximal growth of MDS CFU-E and BFU-E was detected at a 4-fold higher rhEPO concentration than required by control erythroid progenitors. Nine of the patients evaluated exhibited maximal growth of erythroid colonies at 5- to 20-fold higher than control saturating rhEPO concentrations. Circulating EPO levels in MDS patients were elevated, with a mean value approximately 35-fold higher than that of controls. The frequency of MDS marrow CFU-E and BFU-E was 57 +/- 42% and 18 +/- 9% of the mean control values, respectively. Correlation analysis of the relationships between MDS EPO levels and erythroid progenitors indicated that the anemia in MDS is not attributable to an abnormality in the capacity of EPO to induce the generation of CFU-E, but may be influenced by the BFU-E population, whose severe deficiency results in insufficient influx of EPO-responsive cells. Our findings therefore suggest that treatment of MDS patients with rhEPO may be of limited benefit, since the generation of BFU-E from more primitive ancestors and the initial growth requirements of these cells are not under the regulatory influence of this hormone.