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Query: UNIPROT:P04141 (granulocyte-macrophage colony-stimulating factor)
 6,790 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An increasing amount of data provides strong evidence for the complex multifactorial control of primary hemopoietic functions. Here we present a new multicellular functional unit, the Hematon, isolated from the light-density floating fraction of normal human bone marrow (BM) aspirates. The Hematon is organized in a compact, three-dimensional spheroid complex from central adipocytes, fibroblastoid cells, and resident macrophages that compartmentalize myeloid, erythroid, and megakaryocyte progenitor cells and their progenies. The Hematon fraction is more than twofold more abundant in progenitor cells when compared to the mononuclear cell (MNC) fraction as gauged by cytological techniques and by analysis of granulocyte-macrophage colony-forming unit (GM-CFU) populations. Individual Hematons may produce, within 2-3 weeks, up to 50,000 hemopoietic cells of different cell lineages in organotypic microcultures. Recombinant human hematopoietic growth factors interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), and macrophage colony-stimulating factor (M-CSF) significantly stimulated the endogenous cell production of some but not all of the individually treated Hematons, indicating the heterogeneity of factor-responsive cells within the Hematon population. Comparative observations of 184 BM aspirates support the hypothesis that the presence of Hematons in a BM aspirate correlates positively with homeostatic blood cell production, because the Hematon was present in normal BM (31/40) and it was rare among patients with myelodysplastic syndromes (15/53), acute myeloblastic leukemia (7/39), and chronic myelocytic leukemia (5/52). We suggest that the Hematon represents a unifying model around which the variability of fundamental BM functions and dysfunctions can be explored.
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PMID:Hematon, a multicellular functional unit in normal human bone marrow: structural organization, hemopoietic activity, and its relationship to myelodysplasia and myeloid leukemias. 218 30

Granulocyte-macrophage colony-stimulating factor (GM-CSF) was given for three days (8 micrograms/kg/day) to 14 subjects who had solid tumors and normal hemopoiesis. The treatment induced a rapid 3- to 5-fold increase in the number of circulating neutrophils, eosinophils and monocytes. Lymphocytes, platelets and reticulocytes were unmodified during treatment. Activation of circulating neutrophils during GM-CSF treatment was demonstrated by a significant, increased release of neutrophil-derived platelet-activating factor after stimulation with N-formyl-methionyl-leucyl-phenylalanine, tumor necrosis factor-alpha or phagocytosis. The granulomonocytosis was dependent on increased bone marrow production of mature cells. Using the thymidine suicide technique, we observed that GM-CSF more than doubled the percentage of granulocyte-macrophage and megakaryocyte colony-forming units (CFU-gm and CFU-meg) and erythroid burst-forming units (BFU-e) in the S phase of the cell cycle. However, at the level of morphologically recognizable cells with autoradiography, we observed that GM-CSF increased the labeling index of the granulo-monopoietic cells, whereas that of the erythroblasts was unchanged. These data suggest that in accordance with in vitro observations, GM-CSF exerts its activity through all granulo-monopoietic lineages, whereas other cytokines (erythropoietin, thrombopoiesis-stimulating factors) may be needed to fully exploit the proliferative stimulus of GM-CSF on BFU-e and CFU-meg. After treatment discontinuation, the proliferative activity drops to values lower than before treatment, suggesting a period of relative refractoriness of marrow progenitors to the cytocidal effect of cell cycle-specific antineoplastic agents. This hypothesis is under evaluation in a controlled clinical trial where GM-CSF is given prior to chemotherapy.
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PMID:Human GM-CSF in vivo: identification of the target cells and of their kinetics of response. 218 41

The human burst-forming unit-megakaryocyte (BFU-MK) is a primitive megakaryocytic progenitor cell. A marrow cell population enriched for BFU-MK (CD34+ DR-) was obtained by monoclonal antibody labeling and fluorescence-activated cell sorting. CD34+DR- cells were assayed in a serum-depleted, fibrin clot culture system. Recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF), recombinant interleukin-3 (rIL-3), and megakaryocyte colony-stimulating factor (MK-CSF), partially purified from human plasma, were each individually capable of promoting BFU-MK-derived colony formation. Recombinant erythropoietin, rG-CSF, rIL-4, rIL-6, and thrombocytopiesis stimulating factor, partially purified from human embryonic kidney cell conditioned media, had no stimulatory effect on BFU-MK-derived colony formation when added alone or in various combinations with either GM-CSF, IL-3, or MK-CSF, GM-CSF and IL-3, GM-CSF and MK-CSF, but not IL-3 and MK-CSF had additive actions in promoting BFU-MK-derived colony formation, rIL-1 alpha had no influence alone on BFU-MK cloning efficiency, but had a dose-dependent, synergistic effect with IL-3, but not with GM-CSF or MK-CSF. The synergistic relationship between IL-1 alpha and IL-3 was abrogated by addition of an IL-1 alpha neutralizing antibody but not by a GM-CSF neutralizing antiserum, suggesting that IL-1 alpha acts directly on the BFU-MK and not by stimulating marrow auxiliary cells to secondarily release additional cytokines. Information presented here indicates that the regulatory influence, acting on the different stages of megakaryocyte development, are stage-specific and accomplished by multiple cytokines.
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PMID:Cytokine regulation of the human burst-forming unit-megakaryocyte. 219 60

The effects of thrombopoiesis-stimulating factor (TSF) on human marrow megakaryocyte colony formation in vitro were studied by the plasma clot method. TSF was found to stimulate megakaryocyte as well as granulocyte-macrophage colony formation in vitro at optimal concentrations of 200-300 pg/ml of medium containing 2.5% horse serum. This colony-stimulating effect of TSF was not affected by polyclonal antibodies to human (h) interleukin 3 (IL-3) or to granulocyte colony-stimulating factor (G-CSF) but was neutralized by monoclonal or polyclonal antibodies to human granulocyte-macrophage colony-stimulating factor (hGM-CSF). In order to differentiate among cross-reactivity between TSF and hGM-CSF, induction of colony growth via release of GM-CSF, and presence of hGM-CSF in TSF preparations, TSF was tested on murine marrow cells, which are not responsive to hGM-CSF. TSF induced growth of murine megakaryocyte colony-forming units (CFU-MK) and granulocyte-macrophage colony-forming units (CFU-GM) in vitro with a dose response similar to that observed on human marrow cells; however, this effect could not be neutralized by antibodies to either human or murine GM-CSF. Using a double-antibody enzyme-linked immunosorbent assay, TSF preparations were found to contain 36 +/- 4 U of hGM-CSF per picogram of TSF protein. These findings indicate that hGM-CSF is responsible for the megakaryocyte colony-promoting effects of TSF on human marrow cells in vitro.
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PMID:Thrombopoiesis-stimulating factor: its effects on megakaryocyte colony formation in vitro and its relation to human granulocyte-macrophage colony-stimulating factor. 219 4

A liquid culture technique associated with either double staining and flow cytometry or electron microscopy was used to study human megakaryocytopoiesis. During development from the embryo to the adult, a progressive increase in ploidy classes associated with an enhancement of megakaryocyte (meg) size was observed. Granulocyte-macrophage colony-stimulating factor had no effects on adult marrow cultures. In contrast, interleukin (IL) 3 induced a marked proliferation, but was unable to promote polyploidization. Furthermore, it abrogated the effects on endomitosis of aplastic plasma (AP). This negative effect on polyploidization of IL-3 could be partially dissociated from its effects on proliferation by a delayed addition in culture. AP acted on both proliferation and endoreplication, which was not due to the main hematopoietic growth factors, including IL-6. A synthesis of IL-6 was detected by in situ hybridization in cultured cells including megs which also express receptors for IL-6. These results suggest that terminal meg differentiation may be regulated by an autocrine IL-6 loop, and that megakaryocytopoiesis may be independently regulated at early and late stages of differentiation.
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PMID:Regulation of human megakaryocytopoiesis: analysis of proliferation, ploidy and maturation in liquid cultures. 220 61

The effects of recombinant cytokines on the ploidy of human megakaryocytes derived from megakaryocyte progenitors were studied using serum-free agar cultures. Nonadherent and T cell-depleted marrow cells were cultured for 14 days. Megakaryocyte colonies were identified in situ by the alkaline phosphatase anti-alkaline phosphatase technique, using monoclonal antibody against platelet IIb/IIIa. The ploidy of individual megakaryocytes in colonies was determined by microfluorometry with DAPI (4',6-diamidino-2-phenylindole) staining. Recombinant human interleukin 3 (rhIL-3) and recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) supported megakaryocyte colony formation in a dose-dependent manner. However, both rhIL-3 and rhGM-CSF had no definite ability to increase the ploidy values. Recombinant human erythropoietin (rhEpo) or recombinant human macrophage colony-stimulating factor (rhM-CSF) by itself did not stimulate the growth of megakaryocyte progenitors. rhEpo or rhM-CSF, however, stimulated increases in the number, size and ploidy values of megakaryocyte colonies in the presence of rhIL-3 or rhGM-CSF. Recombinant human interleukin 6 (rhIL-6) showed no capacity to generate or enhance megakaryocyte colony formation when added to the culture alone or in combination with rhIL-3. rhIL-6, however, increased the ploidy values in colonies when added with rhIL-3. These results show that rhEpo, rhM-CSF and rhIL-6 affect endomitosis and that two factors are required for megakaryocyte development.
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PMID:The effect of cytokines on the ploidy of megakaryocytes. 220 62

Murine recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) was injected in mice, and the effects on bone marrow, splenic megakaryocytes, megakaryocyte precursors (megakaryocyte colony-forming units [CFU-Meg]) were evaluated. In mice injected three times a day for 6 days with 12,000 to 120,000 U rGM-CSF, no significant modification of both platelet levels and mean platelet volume was observed, while there was a twofold increase in blood neutrophils. However, the rate of platelet production, as assessed by the measurement of 75selenomethionine incorporation into blood platelets, was On the contrary, administration of up to 384,000 U rGM-CSF two times a day for 2 days, as for a typical "thrombopoietin assay," failed to modify platelet production. A significant dose-related increase in the number of splenic megakaryocytes occurred in mice receiving 60,000 to 120,000 U rGM-CSF, while a slight increase in the number of bone marrow megakaryocytes was observed in mice injected with 120,000 U rGM-CSF. The proportion of bone marrow megakaryocytes with a size less than 18 microns and greater than 35 microns resulted significantly higher in mice receiving rGM-CSF in comparison with controls; an increase in the percentage of splenic megakaryocytes greater than 35 microns was also observed. A statistically significant increase in the total spleen content of CFU-Meg was observed after administration of 90,000 and 120,000 U rGM-CSF three times a day for 6 days, while no effect on bone marrow CFU-Meg was recorded, irrespective of the dose delivered. Finally, 24 hours after a single intravenous injection of rGM-CSF, there was a significant increase in the proportion of CFU-Meg in S-phase, with the splenic progenitors being more sensitive than bone marrow-derived CFU-Meg. These data indicate that rGM-CSF has in vivo megakaryocyte stimulatory activity, and are consistent with previous in vitro observations. However, an effective stimulation of megakaryocytopoiesis in vivo, bringing about an increase in the levels of blood platelets, may require interaction of rGM-CSF with other cytokines.
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PMID:In vivo stimulation of megakaryocytopoiesis by recombinant murine granulocyte-macrophage colony-stimulating factor. 220 22

The immunological and biochemical characteristics of murine megakaryocyte potentiator from lung and bone marrow were examined and compared with thrombopoietic stimulatory factor. Biological activity was not neutralized by anti-erythropoietin, but megakaryocyte potentiator activity from all three sources was abolished or reduced when the preparations were treated with anti-thrombopoietic stimulatory factor or anti-interleukin-6. Megakaryocyte potentiator levels in lung conditioned medium were not found to be enhanced from mice treated with lipopolysaccharide, in contrast to granulocyte-macrophage colony-stimulating factor (GM-CSF) levels. The biochemical properties of murine megakaryocyte potentiator from lung and bone marrow were compared and found to be similar in the elution profiles from anion exchange, gel filtration and reversed phase liquid chromatography. It is concluded that the activities in lung and bone marrow are very similar if not identical, to interleukin-6.
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PMID:Tissue sources of murine megakaryocyte potentiator: biochemical and immunological studies. 238 66

The effect of a number of purified or recombinant hematopoietic growth factors, including recombinant erythropoietin (rEpo), thrombocytopoiesis stimulating factor (TSF), recombinant interleukin 1 alpha (rIL-1 alpha), recombinant granulocyte colony-stimulating factor (rG-CSF), macrophage colony-stimulating factor (CSF-1), recombinant interleukin 3 (rIL-3), and recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF), on megakaryocyte (MK) colony formation by normal human marrow cells in a serum-depleted assay system was determined. Neither rEpo, TSF, CSF-1, rIL-1 alpha, nor rG-CSF alone augmented MK colony formation. Both rGM-CSF and rIL-3 at optimal doses increased MK colony formation eightfold and tenfold, respectively, above baseline values. Addition of increasing amounts of either rGM-CSF or rIL-3 led to progressively greater numbers of MK colonies formed until plateau levels were reached. Both rGM-CSF and rIL-3 also led to a dose-related increase in the number of cells per MK colony formed in culture. These molecules were equivalent stimulators of MK colony formation when their effects at optimal concentrations were compared. The effects of rGM-CSF and rIL-3 were additive at suboptimal concentrations of rIL-3 in that colony formation by a combination of the two growth factors approximated the sum of colony formation by each growth factor alone. These data suggest that rGM-CSF and rIL-3 alone and in combination are important regulators of in vitro megakaryocytopoiesis at the progenitor cell level.
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PMID:Effect of recombinant and purified hematopoietic growth factors on human megakaryocyte colony formation. 245 73

We have attempted to evaluate in vivo effects of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) on acute radiation hematopoietic injury in mice. BDF1 mice, irradiated with 7.5-Gy x-rays, were injected i.p. twice daily for 10 days with 10(5) U recombinant human G-CSF, 3.75 x 10(5) U recombinant murine GM-CSF, or a combination of both. G-CSF significantly enhanced the recovery of not only peripheral leukocytes but also platelets and hematocrit on days 14 and 21 after irradiation. GM-CSF significantly enhanced the recovery of platelets on day 14 and peripheral leukocytes on day 21. G-CSF markedly enhanced the recovery of spleen colony-forming units (CFU-S), colony-forming units in culture (CFU-C), erythroid burst-forming units (BFU-E), and megakaryocyte colony-forming units (CFU-Meg) both in bone marrow and in the spleen. GM-CSF significantly enhanced the recovery of CFU-Meg in bone marrow on day 14. We found synergistic effects between G-CSF and GM-CSF on CFU-S, CFU-C, and CFU-Meg in the spleen on day 14, although we found antagonistic effects between G-CSF and GM-CSF on CFU-S and CFU-C in bone marrow on day 7, and on platelet counts on day 7. These results indicate that the administration of recombinant G-CSF and GM-CSF may be useful in accelerating hematopoietic recovery in patients with acute radiation hematopoietic injuries.
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PMID:Effects of recombinant granulocyte colony-stimulating factor (rG-CSF) and recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) on acute radiation hematopoietic injury in mice. 247 60


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