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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)

Functional pleiotropy and redundancy are characteristic features of cytokines. Interleukin 6 (IL-6) is a typical example: IL-6 induces cellular differentiation or expression of tissue-specific genes; it is involved in processes such as antibody production in B cells, acute-phase protein synthesis in hepatocytes, megakaryocyte maturation, cytotoxic T cell differentiation, and neural differentiation of PC12 (pheochromocytoma) cells. It promotes growth of myeloma/plasmacytoma cells, T cells, keratinocytes and renal mesangial cells, and it inhibits growth of myeloid leukaemic cell lines and certain carcinoma cell lines. The IL-6 receptor consists of two polypeptide chains, a ligand-binding chain (IL-6R) and a non-ligand-binding, signal-transducing chain (gp130). Interaction of IL-6 with IL-6R triggers the association of gp130 and IL-6R, and the signal can be transduced through gp130. Association of gp130 with IL-6R is involved in the formation of high affinity binding sites. This two-chain model has been shown to be applicable to receptor systems for several other cytokines, such as granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-3, IL-5 and nerve growth factor (NGF). The pleiotropy and redundancy of cytokines may be explained on the basis of this unique receptor system.
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PMID:The molecular biology of interleukin 6 and its receptor. 142 18

Leukemia inhibitory factor (LIF) and interleukin-6 (IL-6) are multifunctional cytokines with many similar activities. LIF is structurally and functionally related to another cytokine, Oncostatin M (OSM), that binds to the high-affinity LIF receptor but not to the low-affinity LIF receptor. A complementary DNA was isolated that encodes the high-affinity converting subunit of the LIF receptor. The converter conferred high-affinity binding of both LIF and OSM when expressed with the low-affinity LIF receptor and is identical to the signal transducing subunit of the IL-6 receptor, gp130. The gp130 subunit alone confers low-affinity binding of OSM when expressed in COS-7 cells. This receptor system resembles the high-affinity receptors for granulocyte-macrophage colony-stimulating factor, IL-3, and IL-5, which share a common subunit.
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PMID:The IL-6 signal transducer, gp130: an oncostatin M receptor and affinity converter for the LIF receptor. 154 94

We examined the effects of recombinant human erythropoietin (rhEPO), recombinant murine interleukin 3 (rmIL-3), recombinant human interleukin 6 (rhIL-6), recombinant human interleukin 11 (rhIL-11), recombinant murine leukemia inhibitory factor (rmLIF) and recombinant murine granulocyte-macrophage colony-stimulating factor (rmGM-CSF) on the growth of murine megakaryocytic cell lines. In serum-free methylcellulose culture supplemented with bovine serum albumin (BSA), the addition of rhEPO (0.1-10 U/ml), rmIL-3 (10-500 U/ml), rhIL-6 (100-10,000 U/ml), rmLIF (100-10,000 U/ml), or rmGM-CSF (10-1000 U/ml) enhanced colony growth in L8057Y5 cells, which had been maintained in protein-free culture, mostly in a dose-dependent fashion; rhIL-11 did not have any stimulatory effect at the tested doses (10-1000 U/ml). In addition, colony growth of L8057 cells, which had been maintained in serum-containing culture, was enhanced, but to a lesser extent, by the addition of these cytokines except rhEPO (the cultures were supplemented with 1% fetal bovine serum. Among the cytokines that showed growth-enhancing effects on L8057 cells, the expression of mRNAs encoding receptors for EPO, IL-6 and IL-3 was examined by northern blot analysis or reverse transcription polymerase chain reaction (RT-PCR). In both cell lines, mRNAs for EPO-R, IL-6R, gp130, IL-3R alpha and beta chains were constitutively expressed. The results suggest that L8057 and L8057Y5 cell lines have characteristics of megakaryoblastic cells in their biological responses to cytokines, as well as in the expression of cytokine receptor mRNAs, and that the growth-enhancing effects of these cytokines on the cell lines may be achieved through specific receptors. Our findings show the value of these cell lines for investigating the mechanisms of growth signal transduction in megakaryopoiesis.
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PMID:Effects of erythropoietin, IL-3, IL-6 and LIF on a murine megakaryoblastic cell line: growth enhancement and expression of receptor mRNAs. 786 46

Studies in recent years have suggested that human tumor cell lines are capable of responding in vitro to hematopoietic growth factors. In the present study, we investigate the transcription of the alpha and beta subunits of granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor, the alpha and beta subunits of interleukin 3 (IL-3) receptor, and the single subunit of interleukin 6 (IL-6) receptor and its associated gp130 transduction protein by PCR amplification of reverse-transcribed cellular mRNA in 34 malignant cell lines derived from a variety of histological cell types. mRNA for only a single subunit polypeptide was found in a significant minority of cell lines (23%), while in 20% both the alpha and beta subunits of either the GM-CSF receptor or the IL-3 receptor were detected among a number of different histological cell types. Transcription of the gene encoding the IL-6 receptor was found in 38% of cell lines, and all lines transcribed the gp130 transduction protein, consistent with previous observations on the ubiquity of that polypeptide. In order to test the in vitro effect of exogenously added growth factors on those malignant cell lines transcribing complete cytokine receptor, either GM-CSF, IL-3, or IL-6 was added in therapeutic concentrations (20-500 ng/ml) and cellular proliferation was measured by incorporation of [3H]thymidine. No stimulation was seen at either 3 and 6 days of culture. Production of cytokine by these cell lines was investigated at the level of transcription and by assay of peptide product. None transcribed mRNA for either GM-CSF or IL-3, while 5 of 6 (STD, DOZ, ADE, Hep-2, and Detroit) expressed IL-6 mRNA. Of these latter, 2 cell lines (ADE and Hep-2) produced IL-6 as determined by bioassay, while none produced GM-CSF or IL-3 by enzyme-linked immunosorbent assay. This suggests that in the case of GM-CSF and IL-3, failure to proliferate on addition of cytokine is not due to the prior presence of endogenous production. In contrast, at least a subset of malignant cell lines may involve a closed IL-6 autocrine loop saturating cell surface sites. These findings suggest that the ability to transcribe the genes encoding cytokine receptor is by itself insufficient to render cells cytokine responsive and that malignant cells may lack the cellular machinery for cytokine-induced proliferation. This in turn suggests that therapeutic administration of either GM-CSF, IL-3, or IL-6 may involve no additional risk of tumor regrowth in vivo.
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PMID:Transcription of genes encoding granulocyte-macrophage colony-stimulating factor, interleukin 3, and interleukin 6 receptors and lack of proliferative response to exogenous cytokines in nonhematopoietic human malignant cell lines. 831 22

AML-193 is a cytokine-dependent human leukemia cell line established from the bone marrow of an M5-type acute monocytic leukemia (AML) patient. The effect of recombinant human interleukin-6 (rhIL-6) on the proliferation of AML-193 cells was investigated. Both granulocyte-macrophage colony-stimulating factor (rhGM-CSF) and rhIL-3 promoted the DNA synthesis and growth of AML-193 cells in vitro. rhIL-6 alone did not support the growth of AML-193 cells, yet pretreatment of AML-193 cells with rhIL-6 markedly enhanced their proliferative response to subsequent rhGM-CSF or rhIL-3 stimulation. The growth-promoting effect induced by rhIL-6 was attributable in part to the upregulation of GM-CSF receptors on AML-193 cells; treatment of AML-193 cells with rhIL-6 for 24 to 48 hours greatly increased their GM-CSF binding activity, which occurred in a dose-dependent manner. Both the growth-promoting and receptor-upregulating effects induced by rhIL-6 could be blocked by treating AML-193 cells with neutralizing anti-gp130 antibodies (GPX7). Treatment of AML-193 cells with anti-gp130 antibodies alone also led to a notable decline in GM-CSF binding activity, suggesting a possible role of gpl30 in regulating the expression of GM-CSF receptors. When AML-193 cells were starved in cytokine-free medium and then restimulated with rhGM-CSF, a rapid increase (5 minutes) in lyn kinase activity was observed. A similar upregulation of lyn kinase activity by rhIL-6 treatment also was noted in AML-193 cells, but only after a prolonged incubation of the cells with rhIL-6 (>24 hours). These findings show that the growth-promoting effects of rhIL-6 are mediated through the upregulation of GM-CSF receptors on AML-193 cells by mechanisms that appear to involve the activation of both gp130 and lyn kinase.
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PMID:Regulation of granulocyte-macrophage colony-stimulating factor (GM-CSF) receptors in a GM-CSF-dependent human myeloid leukemia cell line (AML-193) by interleukin-6. 864 72

gP130 transducing receptor is involved in the formation of high affinity receptors for the cytokines of the interleukin-6 (IL-6) family. Recruitment of gp130 by IL-6 associated to its receptor leads to the dimerization of the transducing component. In the present study we did characterize the B-S12 monoclonal antibody raised against gp130 and able to elicit IL-6 type biological activities. B-S12 antibody triggered strongly the proliferation of TF1 and XGI hematopoietic cell lines and was able to increase the synthesis of acute phase proteins in HepG2 hepatoma cell line. B-S12 also behaved as a synergistic factor with granulocyte-macrophage colony-stimulating factor for both proliferation and differentiation of CD34-positive hematopoietic cell progenitors. By using a symmetric enzyme-linked immunosorbent assay, allowing the detection of dimeric forms of soluble gp130, we found that addition of B-S12 to gp130 led to its dimerization. Analysis of the tyrosine phosphorylation events in gp130 and Jak kinase family members revealed that B-S12 quickly induced the phosphorylation of gp130 in a neural derived cell line, and that Jak1 and Jak2 were also recruited. In conclusion, we show that gp130 cross-linking with the B-S12 monoclonal antibody was sufficient to generate functional IL-6 type responses in hematopoietic, neural, and hepatic cells.
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PMID:gp130 transducing receptor cross-linking is sufficient to induce interleukin-6 type responses. 866 9

Mast cells (MC), blood basophils (Ba) and monocytes (Mo) are of haemopoietic origin. Lineage-relationships and transdifferentiation between MC and Mo, or MC and Ba, have been considered, based on common expression of antigens. In this study, comparative phenotypic analyses on MC, Ba and Mo and on respective cell lines were performed using monoclonal antibodies (mAb) to previously defined and novel CD antigens (CD1-130). By cluster analysis, the overall (all 130 CD) phenotypic relationships (given as similarity indices, SI), between primary cells (MC, Ba and Mo) and corresponding cell lines (HMC-1, KU-812, U937) were 0.716, 0.779 and 0.757, respectively. When primary cells were compared, lower SI values were found (MC versus Ba, 0.509; MC versus Mo, 0.625; Mo versus Ba, 0.698). More distant relationships were found between MC versus Ba and MC versus Mo, compared with Ba versus Mo, for adhesion receptor (R)-, complement R- and cytokine R profiles. Analysis of cytokine R revealed most significant dissimilarities between MC versus Ba and MC versus Mo (SI < 0.2). Moreover, in contrast to other CD subgroups and other lineages, MC and HMC-1 differed from each other in cytokine R expression (SI = 0.286). Cytokine R detectable on HMC-1 but not MC were granulocyte-macrophage colony-stimulating factor (GM-CSFR)alpha(CD116), CD40, Apo-1/FAS(CD95) and gp130(CD130). Cytokine R detectable on Ba but not MC, were interleukin-3 (IL-3)R alpha(CD123), IL-1RII(CD121b), IL-2R alpha(CD25) and CD40. In summary, MC, Ba and Mo display a unique CD profile with MC being the most distantly related cell. The most significant mismatch within a given lineage is the loss of cytokine R on mature MC as compared with normal myeloid progenitors and HMC-1 cells.
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PMID:Comparative immunophenotypic analysis of human mast cells, blood basophils and monocytes. 867 6

It is well established that granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-1 and tumour necrosis factor-alpha (TNF-alpha) are involved in Langerhans' cell (LC) development and dendritic cell traffic. However, little is known about the pattern of cytokine receptors on human LC and their modulation during different stages of maturation. The expression of cytokine receptors was studied by flow cytometry on both freshly isolated LC (fLC) and 72-hr cultured LC (cLC). Epidermal cell suspensions enriched in LC were obtained after skin trypsinization and Ficoll-Hypaque gradient. LC were identified by their CD1a positivity. Although the majority of fLC were positive for the alpha chain of GM-CSF receptor (GM-CSFR), the beta chain of GM-CSFR was detected only on 15% of CD1a+ cells. fLC were also positive for IL-1 receptor (IL-1R) type 1, IL-1R type 2, 75,000 molecular weight TNF receptor (TNFR) and interferon-gamma receptor (IFN-gamma R). IL-6R and its transducing signal gp130 were present in a subset of fLC. Granulocyte colony-stimulating factor receptor (G-CSFR), macrophage colony-stimulating factor receptor (M-CSFR), the alpha and beta chain of IL-2R, IL-4R, IL-7R, IL-8R and 55,000 molecular weight TNFR were not detected on fLC. After culture, LC up-regulated the expression of both the alpha and beta chains of GM-CSFR, IL-1R type 2, alpha and beta chains of IL-2R, IL-6R and gp130. In contrast, IL-1R type 1 and 75,000 molecular weight TNFR were down-modulated and the expression of IFN-gamma R was not affected by culture. These results suggest that LC undergo changes in the cytokine receptor repertory during in vitro maturation.
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PMID:Flow cytometric analysis of cytokine receptors on human Langerhans' cells. Changes observed after short-term culture. 869 97

Because leukemia inhibitory factor (LIF) has little or no effect on murine hematopoietic progenitor cell growth yet enhances hematopoiesis in vivo, we sought to determine whether the effects of LIF were directly or indirectly mediated, or a combination of both. Although LIF alone or in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-3 (IL-3) has no effect on colony formation of unfractionated bone marrow cells (BMCs), it enhances M-CSF-induced colony formation. In comparison, LIF synergizes with IL-3, GM-CSF, M-CSF, and Steel Factor (SLF) to promote the colony formation of partially purified lineage-negative (Lin-) BM progenitors without altering their differentiation. These effects were directly mediated since identical results were observed in single-cell assays. Comparing the effect of LIF with other members of this subclass of hematopoietins (IL-6, oncostatin M [OSM], and ciliary neurotrophic factor [CNTF]), we found that while LIF and IL-6 equally synergize with M-CSF and SLF to promote the colony formation of Lin- BMCs, OSM, and CNTF have no effect. In agreement with OSMs ability to directly bind gp130, preincubation of BMCs with OSM inhibits progenitor cell growth stimulated by the combination of LIF or IL-6 plus SLF. LIF can also directly enhance the growth of further purified more primitive Lin- c-kit+ progenitor cells in the presence of IL-3, GM-CSF, or SLF. Thus, LIF can directly synergize with growth factors to promote the proliferation of purified hematopoietic progenitors, suggesting that the direct effects of LIF on hematopoietic cell growth can, in part, explain the observed hematopoietic effects in vivo. This is a US government work. There are no restrictions on its use.
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PMID:Direct synergistic effects of leukemia inhibitory factor on hematopoietic progenitor cell growth: comparison with other hematopoietins that use the gp130 receptor subunit. 870 42

The beta-chain of the granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and interleukin-5 (IL-5) receptors functions as a communal receptor subunit and is often referred to as beta common (betac). Analogous to other shared receptor subunits including gp130 and the IL-2R gamma chain, betac mediates high affinity binding and signal transduction of all of its ligands. It is not clear, however, how these common receptor subunits can recognize several ligands and indeed whether they exhibit a common binding pocket to accomplish this. We have performed molecular modeling of betac based on the known structures of the growth hormone and prolactin receptors and targeted the putative F'-G' loop for mutagenesis. Substitution of this whole predicted loop region with alanines completely abrogated high affinity binding of GM-CSF, IL-3, and IL-5. Individual alanine substitutions across the loop revealed that a single residue, Tyr421, is critical for high affinity binding of GM-CSF, IL-3, and IL-5, whereas alanine substitution of adjacent residues has little or no effect on high affinity binding. Significantly, reintroducing Tyr421 into the polyalanine-substituted mutant restored high affinity ligand binding of GM-CSF, IL-3, and IL-5, indicating that within this region the tyrosine residue alone is sufficient for high affinity ligand interaction. Functional studies measuring STAT5 activation revealed that alanine substitution of Tyr421 severely impaired the ability of betac to signal. These results show for the first time that a single residue in a shared receptor subunit acts as a binding determinant for different ligands and may have implications for other receptor systems where communal receptor subunits exhibit hydrophobic residues in their putative F'-G' loops. These results also raise the possibility that a single compound targeted to this region may simultaneously inhibit the binding and function of multiple cytokines.
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PMID:A single tyrosine residue in the membrane-proximal domain of the granulocyte-macrophage colony-stimulating factor, interleukin (IL)-3, and IL-5 receptor common beta-chain is necessary and sufficient for high affinity binding and signaling by all three ligands. 882 38


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