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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)

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor (HGF) that regulates the proliferation and differentiation of cells of the myeloid lineage. It can be produced by a variety of cells. One of the major sources of GM-CSF is activated T cells, which transiently produce this HGF. We used the EL-4 thymoma cell line as a model system to address the molecular basis for GM-CSF regulation in T cells. Both concanavalin A (ConA) and the phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA) induce GM-CSF expression in EL-4 cells. However, the biological activity of GM-CSF in the supernatants of the TPA-stimulated cells was higher than that of ConA-stimulated cells. To elucidate this difference in biological activity levels, we examined how ConA regulates GM-CSF gene expression in EL-4 cells and compared it to the better-characterized regulation by TPA. Peak mRNA levels of GM-CSF occur 6 h after stimulation with either of these two agents. GM-CSF mRNA levels after ConA treatment are lower and decrease significantly after 10 h compared to TPA treatment, which causes much higher levels that persist for at least 24 h. Neither agent alters GM-CSF gene transcription. Actinomycin D chase experiments show that ConA increases the GM-CSF mRNA half-life from less than 30 to 90 min, whereas TPA prolongs it to greater than 3 h. These results indicate that GM-CSF mRNA induction by ConA (in common with TPA) is regulated predominantly via RNA stabilization and that the difference in prolongation of the mRNA half-life provides the primary explanation for the lower levels of GM-CSF mRNA induced by ConA compared to TPA.
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PMID:Concanavalin A-induced granulocyte-macrophage colony-stimulating factor production in a murine T-cell line is posttranscriptionally controlled. 154 98

Phorbol esters (TPA) and concanavalin A (ConA) are known to induce granulocyte-macrophage colony-stimulating factor (GM-CSF) production in murine thymoma EL-4 cells by mRNA stabilization. The role of the 3'-untranslated region (3'-UTR) in GM-CSF mRNA stabilization induced by TPA and ConA in EL-4 cells was examined by transfection studies using chloramphenicol acetyltransferase (CAT) constructions. The GM-CSF 3'-UTR contains a 63-nucleotide region at its 3' end with repeating ATTTA motifs which is responsible for mRNA degradation in a variety of cell types (Shaw, G., and Kamen, R. (1986) Cell 46, 659-666). We produced constructs containing most of the GM-CSF 3'-UTR (303 nucleotides, pRSV-CATgm) or the 3'-terminal AT-rich region (116 nucleotides, pRSV-CATau) and measured CAT enzyme activity and CAT mRNA after transient transfection into EL-4 and NIH 3T3 cells. Low levels of CAT activity were seen in both cells with either plasmid compared with levels of CAT activity obtained with pRSV-CAT. TPA treatment caused an approximately 10-fold increase in CAT activity and mRNA in EL-4 cells transfected with pRSV-CATgm. No increases were seen in EL-4 cells transfected with pRSV-CATau or pRSV-CAT. No response to TPA was detected in transfected NIH 3T3 cells, indicating that the response to TPA is relatively cell-specific. There was no increase in CAT activity after ConA treatment in EL-4 or NIH 3T3 cells transfected with any of the constructs suggesting that the GM-CSF 3'-UTR lacks elements that can respond alone to ConA. Nuclear run-on and actinomycin D chase experiments in EL-4 cells showed that TPA induces CAT activity via mRNA stabilization. By linker-substitution mutagenesis we show that TPA inducibility depends on a 60-nucleotide region of the 3'-UTR whose 5' end is located 160 nucleotides upstream of the 5' end of the AU-rich region.
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PMID:Identification of sequences within the murine granulocyte-macrophage colony-stimulating factor mRNA 3'-untranslated region that mediate mRNA stabilization induced by mitogen treatment of EL-4 thymoma cells. 191 35

The coordinated expression of the hematopoietic growth factors, interleukin 3 (IL3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in activated T cells suggests common synthetic pathways. However, cyclosporin A (CsA) appears to differentially effect the synthesis of these two lymphokines. When the supernatants from the concanavalin A-stimulated thymoma EL-4 or the T-cell hybrid 2B4 were assayed on the GM-CSF/IL3-dependent PT-18 and on the IL3-dependent DA-1 cell lines, IL3 activity could not be detected following CsA treatment, but substantial growth activity, which was identified as GM-CSF, was observed on the PT-18 cell line. CsA did not affect the kinetics of GM-CSF release, but inhibited the release of IL3 over a period of 40 h after the cells were stimulated and treated with CsA. In addition, CsA could be added up to 1 h after stimulation of the cells without affecting GM-CSF activity but inhibiting completely the IL3 activity. To substantiate the inability of CsA to inhibit GM-CSF activity, GM-CSF gene expression was evaluated. By Northern analysis GM-CSF mRNA was not inhibited by doses of CsA up to 1 microgram/ml. The data reveal that CsA can dissociate between the production of IL3 and GM-CSF, suggesting that these two CSFs are regulated by different mechanisms.
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PMID:Granulocyte-macrophage colony-stimulating factor regulation in murine T cells and its relation to cyclosporin A. 304 42

Two growth factors, interleukin 2 (T cell growth factor) and colony-stimulating factor, are produced concomitantly by a murine EL-4 thymoma cell line after stimulation by phorbol myristate acetate. As shown elsewhere, these thymoma-derived factors appear to be biochemically and functionally indistinguishable from the interleukin 2 and colony-stimulating factor produced by mitogen-stimulated mouse spleen cells. Both factors co-elute during gel filtration with apparent m.w. in the range of 30,000, and both exhibit overlapping isoelectric point profiles between pH 4 and pH 5. Because we were unable to separate these 2 factors by methods based on either m.w. or charge, we have used phenyl-Sepharose chromatography, a method based on hydrophobic interactions, to completely separate murine interleukin 2 and colony-stimulating factor. In contrast with published reports, each of the separated factors exhibits unique biologic activities on lymphocytes and macrophages. Interleukin 2 provides help for antibody synthesis in the nude mouse, but neither enhances interferon production by macrophages nor stimulates macrophage growth. Colony-stimulating factor does not enhance antibody synthesis in the nude mouse but does enhance interferon production by macrophages and stimulate macrophage growth.
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PMID:Biologic properties of chromatographically separated murine thymoma-derived Interleukin 2 and colony-stimulating factor. 617 Jun 82

Interleukin 2 (IL-2) production was studied in a subclone of the murine thymoma EL 4. Phenotypic characterization revealed the EL 4-17-2 line to be Thy-1.2+, Lyt-1.2+, and Lyt-2.2-. Costimulation with 500 ng 12-O-tetradecanoylphorbol 13-acetate (TPA)/ml and 5 micrograms concanavalin A (Con A)/ml induced optimal levels of IL-2. Three related phorbol esters stimulated comparable levels of IL-2 when used in conjunction with Con A. Kinetic experiments indicated that IL-2 first became detectable at 2 hours in TPA-treated cultures, whereas in cultures stimulated with Con A alone IL-2 production was not evident until 8 hours. Flow cytometry indicated that TPA and its related phorbol esters cause a perturbation in the cycling of the cell which may be related to increased IL-2 production. Under the conditions examined, no interferon-gamma (IFN-gamma) was detectable. Conversely, both granulocyte-macrophage colony-stimulating factor (CSF-GM) and interleukin-3 (IL-3) were found under conditions that led to stimulation of IL-2 synthesis. CSF-GM was produced in cultures treated singly with 500 ng TPA/ml or with Con A. IL-3 production was similar to IL-2 production, because optimal levels were found in cultures after combined treatment with phorbol ester and mitogen.
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PMID:Multiple lymphokine production by a phorbol ester-stimulated mouse thymoma: relationship to cell cycle events. 641 58

Mouse thymoma line EL-4 cells produce cytokines such as interleukin (IL)-2, IL-3, IL-4, IL-10, and granulocyte-macrophage colony-stimulating factor in response to phorbol 12-myristate 13-acetate (PMA). EL-4 cells also produce low levels of IL-5 when stimulated by PMA alone; however, cAMP greatly augments PMA-dependent IL-5 production. A transient transfection assay revealed that two signals, PMA and cAMP, are required for optimal activation of the IL-5 promoter. In contrast, cAMP almost completely inhibited the PMA-dependent activation of the endogenous IL-2 gene, as well as the transfected IL-2 promoter. These results indicate that the IL-5 gene is positively regulated by cAMP in a manner opposite to that for the IL-2 gene. One of the nuclear factors (NFs) that regulates the response of the IL-5 promoter to cAMP and PMA has properties similar to NF for activated t cell. The P sequence of the IL-4 gene, defined as a responsive element for PMA and calcium ionophore (A23187), shares sequence similarity with the NF kappa B and the NF-activated T cell binding sites. We attempted to determine whether NF(P), a nuclear factor specific for the P sequence, is related to NF-kappa B and nuclear factor for activated T cell (NF-AT). In electromobility shift assays both NF-kappa B (P65 or P65/P50 heterodimer) and NF-AT bound to the P sequence. However, sequence specificity of NF-AT was more similar to that of NF(P), and only a small amount of P65 was detected in NF(P). These results indicate that a component or components of NF-AT have the potential to reconstitute NF(P), whereas NF-kappa B alone does not account for NF(P) in Jurkat crude extract. Taken together, these results suggest that NF-AT-like factors are involved in the regulation of IL-4 and IL-5 genes.
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PMID:Signals and nuclear factors that regulate the expression of interleukin-4 and interleukin-5 genes in helper T cells. 808 67

Phorbol myristate acetate (PMA) treatment of an EL-4 thymoma cell line (EL-4FARRAR) induced secretion of a factor that inhibited intracellular killing of Leishmania major amastigotes by activated macrophages. Analysis of the cytokines produced by EL-4 cells after PMA stimulation identified interleukin-2 (IL-2, 2500 U/ml), IL-4 (1280 U/ml), interferon-gamma (IFN-gamma; 100 U/ml), and granulocyte-macrophage colony-stimulating factor (GM-CSF; 50 U/ml). Neither tumor necrosis factor nor transforming growth factor beta (TGF-beta) was detected. Each of the cytokines present in EL-4 fluids was assessed for capacity to activate macrophages for destruction of parasites or to suppress intracellular killing. IFN-gamma and GM-CSF both activated macrophages to kill Leishmania; IL-2 and IL-4 had no activity for induction of this antimicrobial effector function. IL-2 and IL-4 were tested for their capacity to inhibit lymphokine- or IFN-gamma-induced destruction of L. major by macrophages: IL-4 was ineffective, but IL-2 markedly suppressed the activation of macrophages for intracellular killing. Addition of > or = 10 U/ml of IL-2 at the time of infection, or up to 4 h before, blocked up to 100% of the capacity of activated macrophages to kill intracellular amastigotes. Immunoaffinity treatment of EL-4 fluids with anti-IL-2 antibody resulted in > 80% reduction in suppression of intracellular killing. The suppressive effects of IL-2 were not direct, but mediated by TGF-beta. IL-2 induced resident peritoneal macrophages to secrete > 5000 pg/ml TGF-beta 1, a quantity that is > 500-fold higher than constitutive background levels (20-40 pg/ml) and is sufficient to block intracellular killing activities. This increase in secretion of TGF-beta was not dependent increases in TGF-beta 1 mRNA. Treatment of cultures with EL-4 fluids or recombinant IL-2 in the presence of antibody to TGF-beta 1 blocked the suppressive activity of both. Thus, IL-2 was the major suppressor factor in EL-4 fluids, and it acted indirectly through the induction and autocrine action of TGF-beta.
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PMID:Interleukin-2 suppresses activated macrophage intracellular killing activity by inducing macrophages to secrete TGF-beta. 828 43

There is increasing evidence that spontaneous anticytokine autoantibodies are associated with chronic infections and autoimmune diseases. We report the sporadic occurrence in autoimmune diseases of such autoantibodies to granulocyte-macrophage colony-stimulating factor (GM-CSF), a cytokine involved in inflammation and the regulation of proliferation, differentiation and function of granulocytic and monocytic cell lineages. In 41 of 425 patients tested, we found low to moderate levels of autoantibodies binding to GM-CSF in serum or plasma. These were most prevalent in patients with myasthenia gravis (MG). However, neutralizing autoantibodies against GM-CSF were very rare, being found in only three patients. Two had autoimmune MG, one with thymoma (Patient A) and the other (Patient B) with 'seronegative' MG, i.e. without the antiacetylcholine receptor autoantibodies characteristic of most MG patients, and a third (Patient D) had multiple sclerosis. Only very limited amounts of Patient A and Patient D serum/plasma were available for analysis and therefore further studies were carried out on the more plentiful samples from Patient B. The anti-GM-CSF autoantibodies of Patient B were predominantly polyclonal immunoglobulin G and strongly neutralized recombinant human (rh) GM-CSF derived from different expression systems. They had similar immunological and immunochemical characteristics to anti-GM-CSF antibodies that developed in immunocompetent colorectal carcinoma patients following (rh)GM-CSF therapy. In serial samples from Patient B, the anti-GM-CSF autoantibodies were undetectable from diagnosis at age 8 years until at least age 13, but then developed spontaneously during (temporary) withdrawal of immunosuppressive treatment. Their neutralizing activity has persisted since their first detection at age 15 years 1 month, and was at its highest level recently at age 17 years 7 months. There was no obvious association with other autoimmune phenomena, nor were any haematological deficiencies overtly manifested, suggesting that any loss of GM-CSF function may have been compensated for by other cytokines.
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PMID:Spontaneously occurring neutralizing antibodies against granulocyte-macrophage colony-stimulating factor in patients with autoimmune disease. 1044 77