Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05231 (interleukin-6)
 23,907 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Our present study was designed to clarify the mechanism by which the same megakaryocyte progenitor cells respond to various cytokines at different stages of megakaryocyte development. We examined the changes in mRNA expression of granulocyte macrophage colony-stimulating factor receptor beta-subunit (GM-CSFR beta-subunit), which was a common subunit of a high-affinity interleukin-3 receptor (IL-3R) and a high-affinity GM-CSFR, and interleukin-6 receptor (IL-6R) during megakaryocyte development in a human megakaryocytic leukemia cell line (CMK) which could proliferate and/or differentiate in the presence of 12-O-tetradecanoylphorbol 13-acetate (TPA), IL-3, GM-CSF, and IL-6. We found that GM-CSFR beta-subunit mRNA was expressed constitutively in CMK cells and was transiently down-regulated by TPA and IL-6, while the expression of IL-6R mRNA was increased by TPA in association with the differentiation of megakaryocytes. Furthermore, the TPA-induced down-regulation of GM-CSFR beta-subunit mRNA expression and its recovery were blocked by cycloheximide (CHX), a protein synthesis inhibitor, suggesting that these modulations required de novo protein synthesis. These findings imply that multi-lineage cytokines such as GM-CSF and IL-3 may contribute preferentially to the regulation of the earlier development of megakaryocyte progenitor cells with high densities of multi-lineage cytokine receptors, while IL-6 may be limited in its action to supporting the maturation of more differentiated megakaryocyte progenitor cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Modulation of GM-CSF receptor beta-subunit and interleukin-6 receptor mRNA expression in a human megakaryocytic leukemia cell line. 129 Sep 64

The "stromal" or adherent cells of long-term murine Dexter explant bone marrow cultures provide the best in vitro model of the bone marrow microenvironment. Colony-stimulating factor-1 (CSF-1) is produced constitutively by these cells and is easily detected, but most investigators have not found constitutive production of the other hemolymphopoietic cytokines. We have previously reported the detection of granulocyte-macrophage-CSF (GM-CSF) in murine stromal cultures and its induction by the lectin Pokeweed mitogen. The present studies analyzing stromal cytokine messenger RNA (mRNA) production by standard Northern blot analysis show constitutive production of mRNAs for CSF-1, GM-CSF, granulocyte-CSF (G-CSF), c-kit ligand (KL), and interleukin-6 (IL-6), but not IL-3, IL-4, or IL-5 by 3-week irradiated or nonirradiated murine Dexter stromal cells. Exposure of stromal cells to Pokeweed mitogen or IL-1 16 hours before RNA harvest induces the messages for GM-CSF, G-CSF, KL, and IL-6, but not IL-3, IL-4, IL-5, or CSF-1. Polymerase chain reaction amplification of cDNA made with reverse transcriptase from stromal RNA using two separate sets of IL-3-specific primers shows the presence of IL-3 message in irradiated stromal cells, which is only detectable with this more sensitive technique. The factor-dependent cell lines FDC-P1 and 32D are supported by the stromal cells without the addition of exogenous growth factors, demonstrating a cytokine activity in these cultures that is inhibited by the addition of anti-IL-3 or anti-GM-CSF antibodies. These data indicate that murine Dexter stromal cells constitutively produce CSF-1, GM-CSF, G-CSF, IL-6, KL, and IL-3. This growth factor production could explain the support of granulocyte, macrophage, and megakaryocyte production and stem cell maintenance in Dexter-type long-term murine bone marrow cultures.
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PMID:Biologic significance of constitutive and subliminal growth factor production by bone marrow stroma. 137 43

Recombinant acidic human fibroblast growth factor (aFGF) significantly stimulated the formation of megakaryocyte colonies and the size of MK colonies as well as individual MKs in vitro in mice. When aFGF was combined with recombinant mouse interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-6 (IL-6) at their optimal doses, a synergistic action was found between aFGF and IL-3. The activity of aFGF could be completely abrogated by a monoclonal antimouse IL-6 antibody which specifically neutralized the action of mouse IL-6 but not human IL-6. These data indicate that aFGF provides positive growth signals of megakaryocyte progenitor cells, which can give rise to a synergistic action in the presence of IL-3 and which can be abrogated by the antimouse IL-6 antibody.
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PMID:Recombinant acidic human fibroblast growth factor (aFGF) stimulates murine megakaryocyte colony formation in vitro. 137 45

We examined the role of various hemopoietic factors in the survival of hemopoietic stem cells in methylcellulose culture. Bone marrow cells from 5-fluorouracil (5-FU)-treated mice were cultured without hemopoietic factors. Several days later, a mixture of colony-stimulating factors (CSF interleukin-3 (IL-3), interleukin-6 (IL-6), granulocyte colony-stimulating factor (G-CSF), and erythropoietin (Ep)) was added to the culture (delayed addition of CSF) to induce the maximal colony growth in surviving progenitors. In this system few colonies grew, suggesting that some hemopoietic factors are required for the survival of hemopoietic stem cells in vitro. In a further series of experiments, similar cultures were initiated with single known hemopoietic factors or with a mixture of CSF, followed by the addition of CSF 7 days later. Although IL-3 and G-CSF, as single factors, supported colony growth, the other factors did not. In this experiment, while the total number of colonies in cultures initiated with IL-3 or G-CSF was less than that observed in cultures initiated with a mixture of CSF, the number of multipotential GEMM (granulocyte-erythrocyte-macrophage-megakaryocyte) colonies remained constant. We concluded that IL-3 and G-CSF played important roles as single factors in the survival of murine dormant hemopoietic stem cells in vitro.
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PMID:Interleukin-3 and granulocyte colony-stimulating factor as survival factors in murine hemopoietic stem cells in vitro. 138 Aug 44

The CMK cell line is an acute megakaryoblastic leukemia cell line established from a patient with Down's syndrome, and is known to possess characteristics of normal megakaryocytes. Several cytokines with the ability to stimulate megakaryopoiesis, such as interleukin-3 (IL-3), interleukin-6 (IL-6) and granulocyte-macrophage colony-stimulating factor (GM-CSF), stimulated colony formation by CMK cells. The present study revealed that tumor necrosis factor-alpha (TNF-alpha) stimulated colony formation by CMK cells; the potency was almost equal to that of IL-3, IL-6 or GM-CSF. Scatchard plot analysis revealed that CMK cells possess two types of specific binding sites for TNF-alpha. The high-affinity binding sites had an affinity constant of 0.18 nM, and numbered 5,000. The low-affinity binding sites had an affinity constant of 1.8 nM and numbered 19,000. These results raise the possibility that TNF-alpha can act as a growth-stimulating agent on megakaryocyte-lineage cell line.
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PMID:Tumor necrosis factor-alpha stimulates colony formation by a megakaryoblastic leukemia cell line, CMK. 142 11

Effects of cytokines on murine megakaryocyte (MK) colony formation from either unfractionated marrow cells or purified early haematopoietic cells were studied. Recombinant interleukin-3 (IL3), interleukin-6 (IL6), granulocyte-macrophage colony-stimulating factor (GM-CSF), erythropoietin (Epo) and acidic and basic fibroblast growth factor (aFGF and bFGF) each was able to stimulate MK colony growth although they varied somewhat in their potential. IL6 and FGFs, in addition to their effect on MK colony growth, increased the size of individual MK. The combination of IL3 with IL6 or FGF resulted in an additive action. Monoclonal anti-IL6 antibody completely neutralized the activity of mouse IL6 and FGFs but had no effect on human IL6, mouse IL3 and GM-CSF. When using purified lineage negative marrow cells, only IL3 and IL6 promoted MK colony formation. Transforming growth factor beta 1 (TGF-beta 1) at 10-200 pg/ml selectively inhibited IL3-induced MK colony formation, and at 0.2-0.5 ng/ml it still had no obvious effect on the activity of IL6 or GM-CSF but caused an inhibition of FGF-induced MK colony formation. These data suggest that differential mechanisms are involved in the regulation of megakaryocytopoiesis by IL3, IL6, FGFs and GM-CSF, and that TGF-beta 1 negatively regulates MK development mainly by interfering with the action of IL3.
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PMID:New insights into the regulation of megakaryocytopoiesis by haematopoietic and fibroblastic growth factors and transforming growth factor beta 1. 152 Jun 6

Thrombopoietin or thrombocytopoiesis-stimulating factor (TSF) is known to be the natural stimulator of megakaryocytopoiesis and, thus, stimulates thrombocytopoiesis. In the past 15 years, new assay technology and sources of the hormone have made possible partial characterization of the molecule and clarification of the biologic role of thrombopoietin. Experiments describing the biology and characterization of TSF are reviewed. In addition, a brief history of the molecule, its biology, and the effects of thrombopoietin on both thrombocytopoiesis and megakaryocytopoiesis are discussed, including the effects of thrombopoietin on platelet counts, platelet sizes, and incorporation of isotopes. In the discussion of thrombopoietin's control of megakaryocytopoiesis there is specific information showing that thrombopoietin stimulates an increase in megakaryocyte size and number, DNA content, endomitosis, and maturation. Thrombopoietin also increases the number of early precursor cells of the megakaryocytic series, that is, small acetyl-cholinesterase-positive cells. New information is given on the chemistry of thrombopoietin, along with present assays and the relationship of thrombopoietin to interleukin-6. The clinical aspects of thrombopoietin, with detailed descriptions of several disease states in which decreases and excesses of the hormone have been found, are presented. The potential uses of thrombopoietin in clinical medicine are reviewed. In the near future, it appears that successful gene cloning of the hormone will be achieved, which will allow production of large amounts of recombinant thrombopoietin. The pure material will be helpful in clarifying the hormone's mode of action. Thrombopoietin will no doubt prove to be useful in treating patients with various hematologic disorders, such as patients undergoing bone marrow transplantation, chemotherapy, or radiotherapy, and other patients with various types of marrow hypoplasia.
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PMID:Thrombopoietin. Its biology, clinical aspects, and possibilities. 155 Feb 68

A convenient serum-free fibrin clot culture system for murine megakaryocyte progenitor cells was developed. The culture and counting of colonies is much easier in this system, when compared with previously reported serum-free culture methods. Recombinant murine interleukin-3 (rmIL-3) stimulated megakaryocyte colony formation in a dose-dependent manner in this system. While recombinant human granulocyte colony-stimulating factor (rhG-CSF) had no effect on megakaryocytopoiesis, recombinant human erythropoietin (rhEpo) and recombinant human interleukin-6 (rhIL-6) augmented megakaryocyte colony formation stimulated by rmIL-3. The depletion of adherent cells and T cells from the cultured bone marrow did not eliminate the synergistic effect of rhEpo and rhIL-6.
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PMID:Effects of recombinant cytokines on murine megakaryocyte colony formation in a serum-free fibrin clot culture system. 162 59

The induction of thrombocytopenia results in elevated levels of thrombopoietin (TPO), which can be detected in the plasma of experimental animals. Acute, severe thrombocytopenia (platelet count less than 5% of control) was produced in mice by the administration of either guinea pig or rabbit antimouse platelet antiserum. Control mice received equal volumes of normal serum. At various times after the induction of thrombocytopenia (0.5, 1, 2, 3, 4, 6, 12, and 24 hours) citrated plasma was collected, and circulating interleukin-6 (IL-6) levels were measured using the IL-6-dependent murine hybridoma cell line B9. At no time points after induction of thrombocytopenia were plasma IL-6 levels significantly different from control animals that received normal serum. However, injection of heterologous serum did result in slightly elevated plasma IL-6 levels (at 2 and 3 hours) compared with basal levels measured in uninjected animals. This brief increase was not related to the production of thrombocytopenia. Protein fractions from the plasma of thrombocytopenic rabbits were also tested for the presence of IL-6. Preparations that contained TPO, as shown by stimulation of megakaryocyte maturation in vitro, did not contain detectable levels of IL-6. The ability of the B9 assay to detect the elevation of IL-6 levels in murine or rabbit plasma was verified after the administration of bacterial endotoxin, which is known to increase circulating IL-6 concentrations. IL-6 levels were highly elevated in rabbit or mouse serum after the administration of 5 mg/kg or 1 mg/kg of endotoxin, respectively. Anti-IL-6 antiserum did not neutralize the in vitro megakaryocyte maturation activity of partially purified TPO from the plasma of thrombocytopenic rabbits. In addition, IgG purified from the same antiserum did not neutralize partially purified TPO, as shown after incubation with TPO and subsequent precipitation with agarose-bound protein A. These results show that, unlike TPO, levels of IL-6 do not increase after the induction of acute, severe thrombocytopenia, and strongly suggest that IL-6 does not mediate the thrombopoietic response to acute thrombocytopenia. Although prolonged administration of IL-6 has been shown to induce thrombocytosis, IL-6 and TPO are apparently different and immunologically distinct molecules.
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PMID:Evidence that interleukin-6 does not play a role in the stimulation of platelet production after induction of acute thrombocytopenia. 162 96

Megakaryocytic maturation was analyzed in long-term bone marrow cultures in the absence of added growth factors. Megakaryocytes could be observed for periods of up to 13 weeks in both the supernatant and stromal layer of these cultures. Using acetylcholinesterase staining for enumeration and sizing of megakaryocytes, and a novel rat antimurine platelet monoclonal antibody (MoAb) that detects only megakaryocytes in bone marrow, the number, volume, and ploidy of these cells were assessed microscopically and by flow cytometry. Correlation of these measurements with ambient interleukin-6 (IL-6) levels showed no relationship between IL-6 bioactivity and megakaryocyte number. Conversely, the relatively high IL-6 bioactivity present during the first 2 weeks of culture was correlated with increased megakaryocytic size and ploidy, while the relatively lower IL-6 bioactivity present after week 3 corresponded to decreased megakaryocytic size and ploidy. Addition of neutralizing anti-IL-6 MoAb decreased megakaryocytic size and ploidy at times when ambient IL-6 levels were relatively high, while the addition of exogenous IL-6 increased size and ploidy at times when endogenous IL-6 concentrations were low. The data show that long-term bone marrow cultures can be used as a means to evaluate megakaryocytic maturation in vitro, and suggest that, to some extent, IL-6 plays a role in the maturation process in this system.
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PMID:Megakaryocytic maturation in murine long-term bone marrow culture: role of interleukin-6. 183 56


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