Gene/Protein Disease Symptom Drug Enzyme Compound
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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)

Protracted thrombocytopenia and bleeding remain serious complications in bone marrow transplantation (BMT). Major progress has been made in facilitating myeloid and erythroid engraftment, but little has been made in accelerating thrombopoiesis post-BMT. We report that in vitro preincubation of T cell-depleted BM allografts with a combination of interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) (0.1 microgram/mL each) (n = 8), for 3 days prior to infusion, expands megakaryocyte (MK) precursors. MK-progenitor proliferation was assessed in plasma clot colony assays and liquid cultures following pre-exposure to IL-3/GM-CSF. We observed a 2.8-fold increase in the number of colony-forming units-megakaryocyte (CFU-MK) (17.3 +/- 5.2 vs. 6.1 +/- 3.4) (p = 0.001) and a two-fold increase in burst-forming units-megakaryocyte (BFU-MK) (0.2 vs. 0.1) (p = 0.01) per 2 x 10(5) cells/mL compared to control BM samples cultured for 3 days in medium alone. In secondary cultures, the continued presence of IL-3 and GM-CSF increased the number of CFU-MK by 200-fold (p < 0.0001) over controls and by 9.7-fold over fresh BM. A 33-fold increase (p < 0.0001) in the number of BFU-MK was elicited compared to controls. In addition, IL-3 plus GM-CSF supported increased cellularity within the colonies. The presence of IL-3 or GM-CSF alone resulted in fewer MK colonies and fewer cells per colony than both cytokines combined. In liquid cultures, the percentage of cells expressing platelet glycoprotein (GP) IIb/IIIa in the continued presence of IL-3 and GM-CSF increased following preincubation, yielding a total of 16.0 +/- 2.3 x 10(4) MK/2 x 10(6) cells at day 10 of culture. We propose that ex vivo preincubation with IL-3 and GM-CSF can expand the number of MK precursors and may facilitate platelet recovery post-BMT.
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PMID:Ex vivo expansion of megakaryocyte precursors by preincubation of marrow allografts with interleukin-3 and granulocyte-macrophage colony-stimulating factor in vitro. 758 81

We have further characterized the biological activities, mechanism of action, and target cell populations of recombinant human and murine thrombopoietin (rhTPO and rmTPO) in in vitro human and murine model systems. Alone, hTPO or mTPO stimulated the maturation of immature murine megakaryoblasts as measured in a single cell assay. The combination of hTPO or mTPO and interleukin-6 (IL-6) resulted in a further increase in megakaryocyte differentiation in this system. Murine TPO stimulated mouse megakaryocyte progenitor development. Human megakaryocyte progenitor development was potentiated by hTPO alone and further augmented in the presence of the early-acting cytokines (IL-3) or kit ligand/stem cell factor (KL/SCF). To further define the mechanism of action of TPO, neutralization studies were performed with antisera to IL-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-1 beta, and IL-11. No diminution in TPO activity was observed in the presence of these antisera. Moreover, because adhesive interactions are known to modulate hematopoiesis, we studied whether hTPO might alter such interactions between human bone marrow (BM) megakaryocytes and human BM stromal fibroblasts. No changes were observed in either megakaryocyte expression of the surface molecules lymphocyte function-associated antigen-1, very late activation antigen-4, or intercellular adhesion molecule-1 or the adhesion of megakaryocytes to stromal fibroblasts after treatment with the growth factor. Furthermore, no induction of secretion of the cytokines IL-1 alpha, IL-1 beta, GM-CSF, IL-6, granulocyte-CSF, tumor necrosis factor-alpha, transforming growth factor-beta 1, or transforming growth factor-beta 2 by primary human BM megakaryocytes was noted after treatment of the cells with hTPO. To address whether TPO affects very primitive hematopoietic progenitors, we studied the residual cells from the BMs of mice treated with high doses of 5-fluorouracil. Although no effect of mTPO alone was noted on the viability or replication of such primitive murine progenitor populations, the triple combination of IL-3 + KL/SCF + TPO stimulated growth of megakaryocyte progenitors. These results indicate that TPO is a highly lineage-specific growth factor whose primary biological effects are likely to be direct modulation of the growth and maturation of committed megakaryocyte precursors and immature megakaryoblasts.
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PMID:Modulation of megakaryocytopoiesis by thrombopoietin: the c-Mpl ligand. 763 39

A new culture and quantitation system has been established for growth of megakaryocyte-lineage cells from human progenitor cells. CD34+ progenitor cells were enriched from umbilical cord blood using an avidin-biotin immunoadsorption process. These cells were preincubated in bulk liquid culture for 3 to 4 days in the presence of the growth factors interleukin-3 (IL-3) and IL-6. The cells were then washed and seeded at 5000 cells/well in 96-well plates that contained a variety of test samples. The plates were incubated for 7 days, and the cells were then washed, transferred to ELISA plates, and fixed. Megakaryocyte growth was determined by an ELISA for the platelet glycoprotein (GP) IIb/IIIa, an abundant membrane protein found on cells committed to the megakaryocyte lineage. The growth factor IL-3 was found to produce a very strong signal in this assay. The addition of granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, stem cell factor (SCF), or leukemia inhibitory factor (LIF) to low levels of IL-3 also stimulated megakaryocyte growth, as measured by IIb/IIIa expression. Plasma from patients with aplastic anemia was also stimulatory in this assay, and showed marked synergy with IL-3. This progenitor cell culture system, due to its judicious use of progenitor cells and an automated, 96-well quantitation method, allows for screening large numbers of test samples and multiple combinations and concentrations of growth factors.
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PMID:A new culture and quantitation system for megakaryocyte growth using cord blood CD34+ cells and the GPIIb/IIIa marker. 769 35

The effect of a low-molecular-weight heparin, faxiparin (Nadroparin), on murine megakaryocytopoiesis in vitro and in vivo was studied in comparison with unfractionated heparin. The addition of fraxiparin at 1-20 IU/ml into plasma clot cultures but not serum-free agar culture significantly enhanced MK colony growth. Furthermore, fraxiparin was found to potentiate the stimulating activity of aplastic anaemia serum (AAS) but not stem cell factor (SCF), interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF) and erythropoietin (Epo), on MK colony growth in vitro, and to neutralize the inhibitory effect of platelet factor 4 (PF4) in vitro and in vivo. Fraxiparin also acted synergistically with heparin cofactor II and antithrombin III to promote megakaryocyte colony formation. Intraperitoneal administration of fraxiparin twice daily for 4 d at 0.1-25 IU/injection increased in mice the level of blood platelet counts and the number of single MKs and CFU-MK in bone marrow. These data demonstrate that fraxiparin is able to positively regulate megakaryocytopoiesis.
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PMID:Fraxiparin, a low-molecular-weight heparin, stimulates megakaryocytopoiesis in vitro and in vivo in mice. 781 73

The effects of cytokine stimulation [recombinant human interleukin (rhIL)-1 alpha, rhIL-3, rhIL-6, rhIL-11, and rh granulocyte-macrophage colony-stimulating factor (GM-CSF)] on the secretory activity of normal human megakaryocytes were studied by means of the reverse hemolytic plaque assay (RHPA) in enriched cell preparations. This test facilitates an extremely sensitive determination of cytokine secretion at the single-cell level, together with the clear-cut identification of each immunostained (CD61) secretory active megakaryocyte. Moreover, the reverse transcriptase-polymerase chain reaction (RT-PCR) was used to investigate the expression of IL-6, IL-6 receptor (IL-6R), IL-9, IL-10, IL-12, and IL-13 mRNA in highly concentrated megakaryocyte preparations. In comparison with the spontaneous secretion rate, stimulation with rhIL-1 alpha, rhIL-6, and rhGM-CSF failed to induce a significant increase in the release of cytokines by CD61+ cells. On the other hand, both rhIL-3 and, in a less pronounced way, rhIL-11 exerted a marked effect on IL-6 secretion. Additionally, after stimulation with rhIL-3, a significant enhancement of the secretion of IL-3 and GM-CSF, but not of IL-1 alpha, could be observed. Using the RT-PCR, a significant induction of IL-6 expression could be appreciated in the enriched megakaryocyte population (60% to 80%) stimulated with rhIL-3. The results of this study provide persuasive evidence that a number of cytokines are synthesized and secreted by human megakaryocytes and not only by hematopoietic stroma cells. These data suggest the existence of autocrine and paracrine mechanisms that may influence maturation and differentiation of megakaryocytes as well as act on various stroma cells to sustain an appropriate hematopoietic micro-environment.
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PMID:Secretion of cytokines (interleukins-1 alpha, -3, and -6 and granulocyte-macrophage colony-stimulating factor) by normal human bone marrow megakaryocytes. 783 72

We have established a novel human megakaryoblastic cell line, designated as MEG-A2, from a patient with megakaryoblastic crisis of Philadelphia (Ph) chromosome positive chronic myelogenous leukemia. MEG-A2 cells showed positive phenotypes for periodic acid Schiff and alpha-naphthylbutyrate esterase reactions, but were negative for myeloperoxidase and naphthol ASD chloroacetate esterase reactions. Flow cytometric analyses of cell surface markers revealed that MEG-A2 cells had a low level of GP IIb/IIIa expression as well as apparent expressions of CD4, CD7, CD13, CD33 and CD34 antigens, but no expression of GP Ib nor glycophorin A. Stimulation with phorbol 12-myristate 13-acetate (PMA) dramatically increased the expression of megakaryocyte-related markers such as HPL-3, J15, Pit-1, Y2/51 and AN51 in MEG-A2 cells. The PMA-stimulation also induced expression of platelet peroxidase (PPO) in MEG-A2 cells on electromicroscopic observation. Proliferative responses to granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3) or erythropoietin were observed, and the expression of GP IIb/IIIa was increased by stimulation with GM-CSF, IL-3, erythropoietin and interleukin-6 (IL-6). Protein S mRNA expression was seen in cultured cells on Northern blot analysis. Expression of platelet factor 4 mRNA was induced in PMA-stimulated cells, and a marked accumulation of protein was observed in the culture medium. In conclusion, a new cell line, MEG-A2, belongs to the relatively immature megakaryocytic lineage and has markedly increased megakaryocytic characteristics with PMA stimulation.
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PMID:Establishment and characterization of an immature human megakaryoblastic cell line, MEG-A2. 786 73

We studied the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on the suppression of hematopoiesis associated with the use of the antiviral drug zidovudine (AZT) administered in vivo to normal mice, as determined by measuring peripheral blood indices, and assays of hematopoietic progenitors, i.e. erythroid (CFU-E/BFU-E), myeloid (CFU-GM), and megakaryocyte (CFU-Meg) from bone marrow and spleen. Previous studies from this laboratory have established that dose-escalation zidovudine induced a dose-dependent decrease in hematocrit, WBC, and platelets with altered populations of bone marrow and splenic erythroid, myeloid and megakaryocyte progenitors when administered to normal mice. Daily administration of GM-CSF (10 micrograms/kg/bw) was associated with altered peripheral blood indices and progenitor cells. Dose-escalation AZT, i.e. 0.1, 1.0 and 2.5 mg/ml, was associated with a comparable reduction in all indices, i.e. hematocrit, WBC, and platelets during the 6-week examination period. GM-CSF reduced zidovudine-induced myeloid toxicity (concentration < 2.5 mg/ml) which was associated with an increase in bone marrow and splenic CFU-GM. High concentration, i.e. 2.5 mg/ml still produced myelosuppression irreversible with GM-CSF. GM-CSF induced a reduction in circulating platelets following zidovudine treatment at weeks 2 and 4 with the 1.0 mg/ml and 2.5 mg/ml treatment groups respectively, compared to a persistent decrease in platelets in the presence of zidovudine alone. GM-CSF BFU-E were elevated indicating the restriction in erythoid differentiation was still present. These studies demonstrate GM-CSF influences myeloid and megakaryocyte recovery, but not the erythoid suppression associated with the antiviral drug zidovudine.
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PMID:Prevention of hematopoietic myeloid and megakaryocyte toxicity associated with zidovudine in vivo in mice with recombinant GM-CSF. 795 Sep 2

In this report, we assess the content of primitive hematopoietic progenitor cells (HPC) that circulate transiently in the peripheral blood (PB) of cancer patients (group A) who received a PB stem-cell-mobilizing regimen that included high-dose chemotherapy (HD-CTX) of 7 g/m2 cyclophosphamide followed by a combination of recombinant hematopoietic growth factors (C-HGF), including either interleukin-3 (IL-3) plus granulocyte-colony stimulating factor (G-CSF), IL-3 plus granulocyte-macrophage colony-stimulating factor (GM-CSF), or a recombinant GM-CSF/IL-3 fusion protein (PIXY-321). These data were compared to the HPC content of PB obtained from a similar group of cancer patients that had not received such a mobilization regimen (group B). Monoclonal antibody staining and fluorescence-activated cell sorting (FACS) were used to identify and isolate cell populations enriched for more differentiated HPC (CD34+HLA-DR+) and more primitive HPC (CD34+HLA-DR-). The content of CD34+HLA-DR+ and CD34+HLA-DR- cells in the PB of group A patients was significantly greater than that observed in the PB of group B patients. In addition, HD-CTX plus C-HGF mobilization resulted in the appearance of greater numbers of PB colony-forming units-granulocyte/macrophage, -granulocyte/erythroid/macrophage/megakaryocyte, and -megakaryocyte (CFU-GM, CFU-GEMM, and CFU-Mk), and burst-forming units-erythroid and -megakaryocyte (BFU-E and BFU-Mk) than those observed in the PB of group B patients (p < 0.01). CD34+HLA-DR- cells isolated from the PB of group A patients were capable of initiating long-term hematopoiesis in vitro, which persisted for 10 weeks, while CD34+HLA-DR- cells obtained from the PB of group B patients were capable of sustaining long-term hematopoiesis in vitro for only 4 weeks. As determined by a limiting dilution analysis of group A PB CD34+HLA-DR- cells, the frequency of cells capable of giving rise to hematopoietic progenitor cells (pre-CFC) after 2 weeks in liquid culture was 4.3% (range 1.0-8.3%). Pre-CFC constituted 0.01% (range 0.001-0.02%) of group A PB mononuclear cells, and 151 pre-CFC were calculated to be present in 1 mL mobilized PB (range 20-310/mL). These results suggest that peripheral blood mononuclear cells (PBMC) collected by leukapheresis following HD-CTX plus C-HGF mobilization contain not only differentiated HPC but also more primitive HPC.
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PMID:Characterization and quantitation of primitive hematopoietic progenitor cells present in peripheral blood autografts. 808 76

We have studied the requirements that have to be met to combine effective cancer chemotherapy with the mobilisation of peripheral blood stem cells (PBSC). We have shown that there is a differential induction of high numbers of PBSC following standard-dose chemotherapy (VIP) plus treatment with colony-stimulating factors. The combined sequential administration of interleukin 3 (IL-3) plus granulocyte-macrophage colony-stimulating factor (GM-CSF) induced maximal numbers of PBSC, including colony-forming unit-granulocyte, erythrocyte, monocyte/macrophage, megakaryocyte (CFU-GEMM) and colony-forming unit-megakaryocyte (CFU-Meg), compared with the application of GM-CSF, granulocyte colony-stimulating factor (G-CSF) or chemotherapy alone. The number of CD34+ cells was highly variable depending on the prior treatment given to the patients. Mobilised CD34+ cells--depending on the cytokines used for recruitment--had a varying cloning efficiency, and were heterogeneous as to their level of commitment. Retransfusion of G-CSF-primed progenitor cells to pilot patients following high-dose chemotherapy demonstrated that PBSC recruited by standard-dose chemotherapy plus G-CSF accelerated both neutrophil and platelet recovery.
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PMID:Haematopoietic growth factors and peripheral blood stem cells as supportive agents in dose intensification. 826 Feb 63

Previous work showed that treatment of irradiated mice with a thrombocytopoiesis-stimulating factor (TSF or thrombopoietin) decreased the degree and duration of thrombocytopenia in the period after irradiation. In an attempt to elucidate the radio-protective effects of TSF, femoral megakaryocyte sizes and numbers were measured in mice treated with 3.0 Gy of 137Cs gamma rays and TSF. For controls, other irradiated mice were given human serum albumin (HSA), the carrier protein for TSF, rabbit anti-mouse platelet serum (RAMPS), or normal rabbit serum (NRS); megakaryocyte sizes and numbers were studied on Days 7-14. The results showed that irradiated, TSF-treated mice had significantly larger megakaryocytes on all days assessed compared to HSA-treated control mice. Likewise, RAMPS-treated mice had significantly larger megakaryocytes 14 days after irradiation compared to NRS-treated mice. Megakaryocyte numbers were significantly depressed in TSF-treated mice on Days 7-10 and 14 and on Day 10 in RAMPS-treated mice, compared to their respective controls. Therefore, irradiated mice treated with TSF yielded results similar to RAMPS-treated mice. Megakaryocyte sizes and numbers were also determined for mice treated with 40,000 U/mouse of interleukin-6 (IL-6), 227 U/mouse of granulocyte-macrophage colony-stimulating factor (GM-CSF), or a combination of both cytokines; bovine serum albumin (BSA) was used as a control for these cytokine treatments. Unlike TSF treatment, GM-CSF significantly increased megakaryocyte numbers on both Days 10 and 14; the combination of both growth factors also increased megakaryocyte numbers on Day 14 compared to BSA-treated control mice. However, megakaryocyte size was decreased in GM-CSF-treated mice and in mice treated with both growth factors on Day 10. High levels of IL-6 failed to affect megakaryocyte size or number significantly on any day evaluated. The data of the present report, showing that TSF significantly increases megakaryocyte sizes and platelet counts of sublethally irradiated mice, indicate that thrombopoietin will be useful in treating patients undergoing bone marrow transplantation and/or patients with platelet production problems.
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PMID:Thrombopoietin from human embryonic kidney cells stimulates an increase in megakaryocyte size of sublethally irradiated mice. 832 58


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