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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)

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

We have previously reported that granulocyte-macrophage colony-stimulating factor (GM-CSF) given after the administration of 5-fluorouracil (5-FU) results in augmented hematopoietic recovery as evidenced by increased white blood cell and neutrophil counts. Mice receiving GM-CSF following 5-FU administration were observed to have a marked elevation in splenic granulocyte-macrophage colony-forming cells (GM-CFC) and a decrease in the femoral bone marrow GM-CFC. Because GM-CSF has been shown to increase prostaglandin synthesis and prostaglandins are thought to provide a negative feedback signal to down-regulate myelopoiesis, we sought to determine if the cyclooxygenase inhibitor, indomethacin, could prevent the reduction in the number of femoral bone marrow GM-CFC seen when GM-CSF was administered following 5-FU. Groups of mice received a single 60 mg/kg i.p. injection of 5-FU followed 24 h later by twice-daily injections of 1 micrograms GM-CSF and daily injections of 3, 5, or 6 mg/kg indomethacin; the hematopoietic assays were performed on day 7 following 5-FU. Compared to those animals that received GM-CSF alone following 5-FU, mice receiving 5 mg/kg indomethacin plus GM-CSF following 5-FU had increased numbers of GM-CFC in their bone marrow (3923 +/- 634 vs 971 +/- 138; p less than 0.001) as well as increased neutrophil counts (18,995 +/- 2872 vs 11,497 +/- 2476; p less than 0.01). Indomethacin alone was, in part, capable of facilitating hematopoietic recovery following 5-FU administration, but not to the extent seen when used in combination with GM-CSF. Prostaglandin inhibitors may have a role in combination with hematopoietic growth factors in accelerating hematopoietic recovery following cytoreductive chemotherapy.
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PMID:Indomethacin augments granulocyte-macrophage colony-stimulating factor-induced hematopoiesis following 5-FU treatment. 220 40

We have examined the ability of bryostatin 1 (bryo), an activator of protein kinase C, to induce differentiation of chronic myelogenous leukemia (CML) cells obtained from peripheral blood. Bryo induced a prompt and persistent macrophage-like differentiation, as evidenced by functional, morphological, and immunological criteria. Differentiated cells remained viable for at least 21 days with little change in cell number. CML cell cultures treated in semisolid medium with bryo showed diffuse infiltration with single macrophages, as well as discrete macrophage, mixed, and granulocytic colonies. Supernatants of suspension cultures of bryo-treated CML cells contained granulocyte-macrophage colony-stimulating factor (GM-CSF) by enzyme-linked immunosorbent assay. Furthermore, colony formation could be significantly inhibited by the addition of antibodies to GM-CSF. Prolonged liquid culture of CML cells in bryo reduced colony-forming unit, granulocyte-macrophage content. Bryo-induced differentiation was associated with a decrease in lactoferrin, a marker of granulocyte differentiation, and an increase in both c-fms and interleukin-1 beta RNA, both of which are expressed by monocytes/macrophages. These data demonstrate that bryostatin 1 is capable of inducing macrophage-like differentiation in maturing CML cells. Furthermore, bryostatin induces secretion of GM-CSF by such cells in suspension and semisolid medium and also promotes clonal extinction of granulocyte-macrophage progenitors. Bryostatin may be a possible therapeutic agent for CML.
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PMID:Differentiation and growth modulation of chronic myelogenous leukemia cells by bryostatin. 238 56

Human erythroid burst-promoting activity (BPA) of recombinant growth factors and crude materials, of media conditioned by omentum tissue (OMCM), and of media conditioned by the bladder carcinoma cell line (HTB9CM) was measured by three different culture methods. Using the two-stage culture method, significant activity was shown in OMCM (137%-329% of the control), HTB9CM (102%-333%), recombinant human (rh) granulocyte-macrophage colony-stimulating factor (rhGM-CSF) (179%-220%), rh interleukin 3 (rhIL-3) (232%-676%), and rh insulin-like growth factor 1 (rh IGF-1) (106%-175%), whereas there was no significant increase in the number of erythroid bursts by the same additives when the one-stage culture or the delayed erythropoietin method was employed. Linear dose-response curves were observed in the tested range of rhIL-3 and rhGM-CSF. We also observed that 1) a larger amount of rhGM-CSF was required for the optimal stimulation of erythroid burst-forming units (BFU-E) than for the optimal stimulation of granulocyte-macrophage colony-forming units (CFU-GM), and 2) even the maximum dose of rhGM-CSF increased erythroid bursts to a lesser extent than was possible by the addition of rhIL-3. The former results implies that BPA is not the major activity of GM-CSF, and the latter result, although it is not conclusive, suggests that the GM-CSF-responsive BFU-E represent only a subset population of BFU-E responsive to IL-3. The two-stage culture is a useful assay method for screening BPA in biological materials with respect to accuracy, dose responsiveness, and reproducibility.
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PMID:Three quantitative assays for human erythroid burst-promoting activity of recombinant growth factors and of omentum-conditioned medium. 240 58

Previous studies suggested that the potent immunosuppressive activities of transforming growth factor-beta (TGF-beta) were mediated in part through the inhibition of IL-2-dependent S-phase progression and mitosis of activated T cells. To further investigate the mechanism of T cell growth inhibition by TGF-beta, two constitutively activated murine T cell clones were employed as defined model systems for the growth factor-dependent phase of T cell proliferation. The Th cell line, HT-2, proliferated in response to either IL-2 or IL-4, whereas the cytotoxic T cell line, CT6, exhibited strict dependence on IL-2 for growth stimulation. In both cell lines, picomolar concentrations of TGF-beta inhibited S-phase progression stimulated by IL-2 or IL-4. TGF-beta pretreatment decreased the expression of high affinity IL-2R on HT-2 cells, but not on CT6 cells. In contrast, IL-2-stimulated transferrin receptor expression was markedly inhibited by TGF-beta in both T cell lines. Analyses of growth factor-dependent specific mRNA accumulation revealed that TGF-beta exerted selective inhibitory effects on gene expression in HT-2 and CT6 cells. TGF-beta significantly reduced early (1 to 2 h) increases in c-myc mRNA levels stimulated by IL-2 or IL-4 in both cell lines. In HT-2 cells, TGF-beta pretreatment also inhibited the early increase in granulocyte-macrophage CSF mRNA stimulated by IL-2 or IL-4. The inhibition of c-myc and granulocyte-macrophage cyte-macrophage CSF gene expression by TGF-beta was explained, at least in part, by suppression of the growth factor-dependent transcriptional activation of these genes. These studies suggest that inhibition of c-myc gene transcription may play a fundamental role in the antiproliferative effect of TGF-beta on IL-2- or IL-4-stimulated T cells.
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PMID:Regulatory effects of transforming growth factor-beta on IL-2- and IL-4-dependent T cell-cycle progression. 240 83

Limiting dilution analysis of granulocyte-macrophage progenitor cells was performed by using adherent and T cell-depleted normal human bone marrow and the recombinant human growth factors, granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Estimated frequencies for progenitor cells responding to G-CSF were one in 489 for colonies scored at day 7, and one in 1,015 for day 14 colonies. For GM-CSF the frequencies were one in 1,407 (day 7) and one in 574 (day 14). The effects of tumor necrosis factor (TNF) and lymphotoxin (LT) on the frequency of progenitors responding to either G-CSF or GM-CSF was determined. Both TNF and LT inhibited the response of cells to G-CSF, and in these cultures the frequency of progenitor cells that responded to G-CSF was reduced to less than one in 100,000 cells. In contrast, the frequency of cells able to form colonies in cultures stimulated with GM-CSF was unaltered by either cytotoxin. This differential sensitivity to cytotoxins suggests that either G-CSF and GM-CSF are acting on separate granulocyte progenitor populations or that TNF and LT selectively influence the biochemical pathways associated with the activation of receptors for G-CSF.
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PMID:Human granulocyte-macrophage progenitors and their sensitivity to cytotoxins: analysis by limiting dilution. 244 99

IL-1 is a family of polypeptides which play a critical role in the inflammatory response. Characteristics of this response include an enhanced release of bone marrow neutrophils, activation of circulating and tissue-phase phagocytes, and enhanced production of neutrophils and monocytes. We have sought to understand the hematopoietic response to acute and chronic inflammatory states on a cellular and molecular level. Colony-stimulating factors (CSFs) are glycoproteins involved in the production and activation of neutrophils and monocytes in vitro and in vivo. We have found that quiescent dermal fibroblasts constitutively release granulocyte-macrophage CSF (GM-CSF), granulocyte CSF (G-CSF), and macrophage CSF in culture, and that picomolar concentrations of the inflammatory mediator IL-1 stimulate by at least fivefold the transcription and release of GM-CSF and G-CSF. These findings establish the role of IL-1 in the hematopoietic response to inflammation through the stimulation of the production and release of GM-CSF and G-CSF.
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PMID:Interleukin 1 stimulates fibroblasts to synthesize granulocyte-macrophage and granulocyte colony-stimulating factors. Mechanism for the hematopoietic response to inflammation. 244 27

Highly purified murine granulocyte-macrophage progenitor cells (CFU-GM) were used as target cells to assess the possible direct effects of purified preparations of recombinant murine gamma-interferon, prostaglandin E, recombinant human heavy chain (acidic) ferritin, and recombinant human tumor necrosis factor alpha (TNF-alpha) on progenitor cells in vitro. Target CFU-GM, with cloning efficiencies of up to 84% and containing 0-3% morphologically recognizable accessory cells at the initiation of the culture period, were plated at a density of 100-150 cells/dish in the presence or absence of pure suppressor molecules. Colony formation was stimulated with either crude pokeweed mitogen-stimulated mouse spleen conditioned medium, pure natural murine macrophage colony-stimulating factor, or pure recombinant murine granulocyte-macrophage colony-stimulating factor. All four suppressor molecules were active in vitro against purified CFU-GM as assessed by their ability to inhibit colony or cluster formation. No apparent difference in the degree of responsiveness to prostaglandin E, gamma-interferon, or human heavy chain (acidic) ferritin was noted in the presence of pokeweed mitogen-stimulated mouse spleen conditioned medium, granulocyte-macrophage colony-stimulating factor, or macrophage colony-stimulating factor. In contrast, TNF-alpha in cultures containing macrophage colony-stimulating factor slightly, but significantly, potentiated colony formation. TNF-alpha also appeared more active at suppressing colony formation at lower concentrations in pokeweed mitogen-stimulated mouse spleen conditioned medium than in granulocyte-macrophage colony-stimulating factor-stimulated cultures of purified CFU-GM. The results suggest that TNF-alpha, human heavy chain (acidic) ferritin, gamma-interferon, and prostaglandin E can act directly at the progenitor cell level.
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PMID:Effects of hematopoietic suppressor molecules on the in vitro proliferation of purified murine granulocyte-macrophage progenitor cells. 244 53

Although the genes for four hematopoietic colony-stimulating factors (CSFs) have been cloned, neither the mechanism of the regulation of their production nor their cellular origins have been established with certainty. Monocytes are known to produce colony-stimulating and burst-promoting activities, as well as several monokines such as interleukin-1 (IL-1) and tumor necrosis factor (TNF). These monokines indirectly stimulate other mesenchymal cells to produce certain colony-stimulating factors such as granulocyte-macrophage CSF (GM-CSF). To determine whether monocytes produce other CSFs and if so, to compare the mechanism of regulation of production with that of endothelial cells and fibroblasts, we investigated the synthesis of CSFs by monocytes, human umbilical vein endothelial cells, and fibroblasts. We used total cellular RNA blot analysis to determine interleukin-3 (IL-3), GM-CSF, granulocyte CSF (G-CSF), and monocyte CSF (M-CSF) messenger RNA (mRNA) content and immunoprecipitation or bioassay to confirm the presence of the specific secreted proteins. The results indicate that M-CSF mRNA and protein are produced constitutively by all three cell types and their level of expression does not increase after induction. In contrast, GM-CSF and G-CSF mRNAs are barely detectable in uninduced monocytes and show an increase in expression after lipopolysaccharide treatment. Retrovirus-immortalized endothelial cells, unlike primary endothelial cells or both primary and immortalized fibroblasts, produce IL-1 constitutively; this correlates with their constitutive production of GM-CSF and G-CSF. IL-3 mRNA was not detectable in any of these cells either before or after induction. The results indicate that these mesenchymal cells can produce three CSFs: GM-CSF, G-CSF, and M-CSF; furthermore, the data suggest that the mechanism of regulation of M-CSF production is different from that of GM-CSF and G-CSF, and that the latter two inducible CSFs are regulated by different factors in monocytes compared with the other mesenchymal cells.
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PMID:Interleukin-1, tumor necrosis factor, and the production of colony-stimulating factors by cultured mesenchymal cells. 245 80

The effects of transforming growth factor beta 1 or beta 2 (TGF-beta 1 or -beta 2) on the in vitro proliferation and differentiation of normal and malignant human hematopoietic cells were studied. Both forms of TGF-beta suppressed both the normal cellular proliferation and colony formation induced by recombinant human interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF). In the presence of GM-CSF or IL-3, optimal concentrations of TGF-beta (400 pmol/L) inhibited colony formation by erythroid (BFU-E), multipotential (CFU-GEMM), and granulocyte-macrophage (CFU-GM) progenitor cells by 90% to 100%, whereas granulocyte or monocyte cluster formation was not inhibited. In contrast, neither form of TGF-beta had any effect on G-CSF-induced hematopoiesis. The suppressive action appeared to be mediated directly by TGF-beta since antiproliferative responses were also observed in accessory cell-depleted bone marrow cells. In contrast to normal bone marrow cells, both GM- and G-CSF-induced proliferation of cells from patients with chronic myelogenous leukemia were suppressed in a dose-dependent manner by TGF-beta. Differential effects of TGF-beta on the proliferation of established leukemic lines were also observed since most cell lines of myelomonocytic nature studied were strongly inhibited where erythroid cell lines were either insensitive or poorly inhibited by TGF-beta. These results suggest that TGF-beta is an important modulator of human hematopoiesis that selectively regulates the growth of less mature hematopoietic cell populations with a high proliferative capacity as opposed to more differentiated cells, which are not affected by TGF-beta.
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PMID:Transforming growth factor beta selectively inhibits normal and leukemic human bone marrow cell growth in vitro. 246 Jan 53


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