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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, potentiates superoxide generation produced by human neutrophils stimulated with fMet-Leu-Phe and platelet-activating factor, PAF, but not by phorbol 12-myristate 13-acetate (PMA) or opsonized zymosan. The potentiation is greatest in fMet-Leu-Phe-stimulated cells. This indicates that the actions of only certain receptors are potentiated by GM-CSF. Incubation of the cells with the protein kinase inhibitor H-7 or with the protein synthesis inhibitor cyclohexamide before the addition of GM-CSF does not affect the observed potentiation. The rationales behind these studies are to examine the roles of protein kinase C and protein synthesis in the action of GM-CSF. The data suggest that neither protein kinase C nor protein synthesis is necessary for GM-CSF action. On the other hand, no potentiation can be seen in the presence of cytochalasin B. Unlike intact cells, GM-CSF does not enhance superoxide production by cytoplasts stimulated with fMet-Leu-Phe. The rationale behind the use of cytoplasts is to examine the role of granules and/or nucleus in GM-CSF action, and the data indicate that one or more of these two components is necessary for the priming effect of GM-CSF. The amount of actin associated with the cytoskeleton under control of fMet-Leu-Phe-stimulated condition is the same in normal and GM-CSF-treated human neutrophils. Botulinum D toxin ADP-ribosylates a protein with a molecular weight of 22 kDa. This ribosylation is reduced in homogenates obtained from cells pretreated with botulinum D toxin or GM-CSF. Botulinum D toxin does not affect the basal or the fMet-Leu-Phe-induced rise in the intracellular concentration of free calcium in human neutrophils. GM-CSF also increases the rise in intracellular concentration of free calcium in human neutrophils stimulated with PAF or fMet-Leu-Phe. The increases are inhibited by pertussis toxin. Several important conclusion can be drawn from these data. 1) GM-CSF potentiates the rise in Ca2+i produced by PAF and fMet-Leu-Phe, and these potentiations are inhibited in pertussis-toxin-treated cells. 2) GM-CSF does not prime cytoplasts to stimulation by fMet-Leu-Phe. This suggests that the granules and/or nucleus are necessary for the priming action. 3) The priming by GM-CSF is not mediated by the H-7-sensitive protein kinase C, botulinum D-sensitive G-protein, or protein synthesis.
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PMID:Effect of granulocyte-macrophage colony-stimulating factor on superoxide production in cytoplasts and intact human neutrophils: role of protein kinase and G-proteins. 254 9

The addition of the platelet-activating factor (PAF) to neutrophils causes an increase in cytoskeletal actin, a rise in the intracellular concentration of free calcium, release of arachidonic acid, and the synthesis of PAF. The PAF synthesis in human neutrophils stimulated by PAF is greatly potentiated by the human granulocyte-macrophage colony-stimulating factor. Incubation of human neutrophils with the tumor copromoter phorbol 12-myristate 13-acetate (PMA) for 3 min prior to the addition of the stimulus inhibits all these responses produced by PAF. The inhibition is prevented when the cells are incubated with protein kinase C inhibitors such as 1-(5-isoquinolinesulfonyl)-2-methylpiperazine for 5 min prior to the addition of PMA. The rise in the intracellular concentration of free calcium in human neutrophils stimulated with leukotriene B4 is also inhibited by PMA, and this inhibition is prevented by protein kinase C inhibitors such as staurosporine. Unlike PMA, the inactive ester 4 alpha-phorbol 12,13-didecanoate has no inhibitory effect on the stimulated rise in the intracellular concentration of free calcium. The binding of either PAF or leukotriene B4 to intact cells is inhibited by PMA. The most important finding of the present studies is that PMA interferes with the binding of PAF and leukotriene B4 to their respective receptors. Whether PMA inhibits the binding of these lipid mediators by activating protein kinase C or by perturbing the membrane directly remains to be elucidated.
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PMID:Phorbol 12-myristate 13-acetate inhibits binding of leukotriene B4 and platelet-activating factor and the responses they induce in neutrophils: site of action. 254 88

The mechanism of action of the hemopoietic growth factor, murine interleukin-3 (mIL-3), was investigated using an mIL-3-dependent multipotential hematopoietic cell line, B6SUtA1. Murine granulocyte-macrophage colony-stimulating factor (mGM-CSF) was as potent as mIL-3 in stimulating these cells. In addition, sodium orthovanadate, an inhibitor of phosphotyrosine phosphatase, and 12-O-tetradecanoyl-phorbol-13-acetate (TPA), a known activator of protein kinase C, also stimulated DNA synthesis in these cells, suggesting that protein phosphorylation might be involved in the mechanism of action of mIL-3 and mGM-CSF. To assess this possibility, intact B6SUtA1 cells exposed for brief periods to mIL-3, mGM-CSF, and TPA were analyzed for changes in phosphorylation patterns using metabolic 32P-labeling and antibodies to phosphotyrosine. Both mIL-3 and mGM-CSF induced the serine-specific phosphorylation of a 68-Kd cytosolic protein, whereas all three agents stimulated the serine-specific phosphorylation of a 68-Kd membrane protein. Furthermore, mIL-3 stimulated tyrosine phosphorylation of the 68-Kd membrane protein, as well as of 140-, 90-, 55, and 40-Kd proteins. The 90-Kd protein was also tyrosine phosphorylated in response to mGM-CSF. These phosphotyrosine containing proteins were not detected in TPA-treated cells. These results indicate that protein phosphorylations on tyrosine and serine residues occur in B6SUtA1 cells following short-term incubation with mIL-3 or mGM-CSF and that most of these phosphorylation events are mediated by kinases other than protein kinase C (PkC).
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PMID:Interleukin-3, GM-CSF, and TPA induce distinct phosphorylation events in an interleukin 3-dependent multipotential cell line. 264 75

We studied the ability of the recombinant human-active hemopoietic growth factors granulocyte-macrophage colony-stimulating factor (GM-CSFrh) and granulocyte colony-stimulating factor (G-CSFrh) to activate receptor-mediated transduction pathways which have been implicated in the stimulation of cytotoxic functions in granulocytes. With the use of a panel of fluorescent probes, we found that these two growth factors exerted no detectable immediate effect on the resting transmembrane electrical potential, the intracellular concentration of free calcium ions, or the cytosolic pH of isolated, mature granulocytes. However, when granulocytes were "primed" by preincubation for 90 min with GM-CSFrh or G-CSFrh, the rate of membrane depolarization induced by 10(-7) M N-formyl-methionyl-leucyl-phenylalanine, but not the rate of rise in free calcium ions, was greatly accelerated. In examining potential mechanisms to account for the priming effect of these growth factors, we found that although they did not induce translocation of protein kinase C or stimulate significant degranulation, they each directly caused prompt release of arachidonic acid from plasma membrane phospholipids. Our data indicate that although GM-CSFrh and G-CSFrh do not activate the transduction signals that have most clearly been implicated in receptor-mediated activation of cytotoxic functions in granulocytes--namely, those coupled to membrane depolarization or release of intracellular calcium ions--they appear directly to induce the release of arachidonic acid esterified to membrane phospholipids, an event which may represent the receptor-mediated activation of membrane phospholipases and which may contribute to the "priming" of the cells for enhancement of their functional responsiveness.
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PMID:Effects of recombinant human granulocyte and macrophage colony-stimulating factors on signal transduction pathways in human granulocytes. 311 8

By immunoblotting with antibodies for phosphotyrosine, we have demonstrated that the hematopoietic growth factors interleukin-2, interleukin-3, interleukin-4, and granulocyte-macrophage colony-stimulating factor stimulate the tyrosine phosphorylation of specific sets of proteins in murine hematopoietic progenitor cell lines. The stimulation of tyrosine phosphorylation is a receptor-dependent transient event. The effect of these hematopoietic growth factors on protein tyrosine phosphorylation was not mediated through protein kinase C.
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PMID:Hematopoietic growth factors activate the tyrosine phosphorylation of distinct sets of proteins in interleukin-3-dependent murine cell lines. 326 Mar 30

We have previously shown that granulocyte-macrophage colony-stimulating factor (GM-CSF) gene expression induced by interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha) in the murine stromal cell line +/+.1-LDA 11 involves activation of phospholipase A2 (PLA2). Furthermore, induction of GM-CSF gene expression due to release of arachidonic acid as a result of PLA2 activation was mediated by the transcriptional factor c-jun. In the present study, we have investigated the potential mechanism involved in the induction of c-jun gene expression by arachidonic acid. Arachidonic acid induced transcription of c-jun mRNA. Downregulation of protein kinase C (PKC) by chronic exposure of stromal cells to the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA; 400 nmol/L) did not effect c-jun expression induced by arachidonate. Moreover, pretreatment of cells with the PKC inhibitor, calphostin C (1 mumol/L), caused a marked decrease of c-jun expression induced by TPA, but had no influence on c-jun expression induced by arachidonate. To explore the hypothesis that a tyrosine kinase signalling pathway, independent of PKC activation, was involved in arachidonate-induced c-jun expression, stromal cells were pretreated with the protein tyrosine kinase inhibitor, genistein, before challenge with arachidonic acid. Arachidonate 50 mumol/L)-induced c-jun expression was inhibited, in a dose- and time-dependent manner, by genistein. Genistein similarly inhibited c-jun expression in stromal cells exposed to IL-1 (500 U/mL) plus TNF-alpha (500 U/mL). The potential role of a tyrosine kinase pathway in arachidonate-mediated c-jun expression was further investigated by assaying the tyrosine kinase activity of cells challenged with arachidonic acid, IL-1, and TNF-alpha. Exposure of stromal cells to arachidonic acid induced a 2.1-fold increase in intracellular tyrosine kinase activity determined by phosphorylation of the synthetic peptide, raytide, in the presence of [gamma-32P]-ATP. Similarly, IL-1 and TNF-alpha induced 1.7- and 2.4-fold increases in tyrosine protein kinase activity, respectively. The effect of arachidonic acid on tyrosine kinase activity was inhibited by genistein and was enhanced by sodium vanadate. The increase of protein tyrosine kinase activity detected in arachidonate-stimulated cells was associated, in a dose- and time-dependent fashion, with tyrosine phosphorylation of 240-, 40-, and 29-kD substrates. These results are consistent with the hypothesis that a tyrosine phosphorylation process is triggered by arachidonate as an early event in the signalling pathway that leads to increased expression of c-jun.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Arachidonic acid induces c-jun gene expression in stromal cells stimulated by interleukin-1 and tumor necrosis factor-alpha: evidence for a tyrosine-kinase-dependent process. 757 89

Interferon-gamma (IFN-gamma) is an important immunoregulatory protein produced predominantly by T cells and large granular lymphocytes (LGL) in response to different extracellular signals. In particular, two interleukins (ILs), IL-2 and IL-12, have been shown to be potent inducers of IFN-gamma gene expression in both T cells and LGL. Although it has been reported that there are some T cell lines that produce IFN-gamma in response to IL-2 and IL-12 stimulation, there has as yet been no report of a natural killer (NK) cell line that responds in a similar manner. In this report we present evidence that the cell line NK3.3 derived from human NK cells, responds to both IL-2 and IL-12, as measured by increases in IFN-gamma and granulocyte-macrophage colony-stimulating factor (GM-CSF) cytoplasmic mRNA and protein expression. In addition, when used together IL-2 and IL-12 synergized in the induction of IFN-gamma and GM-CSF and this synergy was attributed to an increased accumulation and stability of the IFN-gamma and GM-CSF mRNAs. To investigate the signaling pathways involved in the gene induction, five inhibitors, cyclosporin A (CsA), transforming growth factor-beta, cycloheximide, genistein, and staurosporine A, were used in analyzing the effects of IL-2 and IL-12 on NK3.3 cells. The results suggest that activation of protein kinase C, but not new protein synthesis, is required for IL-2 induction of IFN-gamma and GM-CSF cytoplasmic mRNA. In contrast, IL-12 induction of IFN-gamma cytoplasmic mRNA appears to only partially depend on activation of protein kinase C. Furthermore, both transforming growth factor-beta and genistein, a tyrosine kinase inhibitor, could suppress IL-2 and IL-12 signaling but CsA was generally inactive. It also was observed that suppression of cytokine gene expression by these agents was independent of the inhibition of proliferation. In addition, IL-2 but not IL-12 induced nuclear factors NF-kappa B and AP1, and regulation of the nuclear levels of these two DNA binding protein complexes is correlated with IFN-gamma and GM-CSF gene expression. These data indicate that IL-2 and IL-12 may have distinct signaling pathways leading to the induction of IFN-gamma and GM-CSF gene expression, and that the NK3.3 cell line may serve as a novel model for dissecting the biochemical and molecular events involved in these pathways.
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PMID:Cellular and molecular mechanisms of IFN-gamma production induced by IL-2 and IL-12 in a human NK cell line. 764 15

We have examined the effect of the macrocyclic lactone protein kinase C (PK-C) activator bryostatin 1 on the proliferative capacity and lineage commitment of CD34+ human bone marrow cells exposed to the granulocyte-macrophage colony-stimulating factor/interleukin-3 (GM-CSF/IL-3) fusion protein pIXY 321. pIXY 321 administered at a dose of 10 ng/mL was as effective as the combination of plateau concentrations of recombinant (r) IL-3 and rGM-CSF (e.g., 50 ng/mL) in stimulating the growth of day-14 committed myeloid progenitors (colony-forming units granulocyte/macrophage [CFU-GM]). In the large majority of samples tested, coadministration of 0.5 to 100 nM bryostatin 1 with either pIXY 321 or the combination of rIL-3 plus rGM-CSF led to modest but significant increases (e.g., 30 to 75%) in the number of CFU-GM, compared to administration of growth factors alone. The degree of bryostatin 1-induced potentiation, however, was considerably less than that previously observed in the case of cells exposed to either rIL-3 or rGM-CSF, where increases of 100 to 150% were regularly noted. While at least 50% of day-14 CFU-GM stimulated by either pIXY 321 or the combination of rIL-3 plus rGM-CSF were of the pure or mixed eosinophilic variety, coadministration of bryostatin 1 resulted in a dramatic inhibition of eosinophilic colonies and a corresponding increase in pure and mixed neutrophil and macrophage colonies. Although coadministration of recombinant granulocyte colony-stimulating factor (rG-CSF) or recombinant colony-stimulating factor-1 (rCSF-1) mimicked the capacity of bryostatin 1 to increase the total number of pIXY 321-induced day-14 CFU-GM, these growth factors, unlike bryostatin 1, were not capable of inhibiting eosinophilic colony formation. Furthermore, whereas addition of neutralizing antibodies to G-CSF or CSF-1 blocked the capacity of these growth factors to potentiate colony formation in the presence of pIXY 321, it did not abrogate the effect of bryostatin 1 on progenitor cell growth or lineage commitment. Finally, in contrast to its effects on committed myeloid progenitors, bryostatin 1 did not increase the growth of erythroid (burst-forming units-erythroid [BFU-E]) and multipotent (multipotent colony-forming units [CFU-GEMM]) progenitors stimulated by pIXY 321, but instead inhibited colony formation at higher concentrations (e.g., 10 to 100 nM).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Modulation of the activity of a human granulocyte-macrophage colony-stimulating factor/interleukin-3 fusion protein (pIXY 321) by the macrocyclic lactone protein kinase C activator bryostatin 1. 768 3

This review concerns the regulation of expression of the two main eosinophil differentiating factors, interleukin-5 (IL-5) and granulocyte-macrophage colony-stimulating factor (GM-CSF). The latter, GM-CSF, is expressed in a wide variety of differentiated and non-differentiated cell types: T cells, monocytes, macrophages, fibroblasts, and endothelial cells. On the other hand, IL-5 is only expressed by a limited number of fully differentiated cells: eosinophils, mast cells, and a subset of T cells. Activation of GM-CSF in T cells and non-T cells occurs by different mechanisms, regulated both transcriptionally and post-transcriptionally. The transcriptional activation of GM-CSF via protein kinase C pathway and via viral transactivating proteins involves different regulatory elements of its promoter. Although one of these cis acting elements is common to IL-5, the activation of IL-5 apparently proceeds via different mechanism(s).
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PMID:Regulation of interleukin-5 and granulocyte-macrophage colony-stimulating factor expression. 795 92

Fibroblasts produce a variety of cytokines including granulocyte/macrophage colony-stimulating factor (GM-CSF). GM-CSF is pivotal for proliferation and function of myeloid cells. In this report, we describe the regulation of GM-CSF gene by irradiation in human fibroblasts. We found that fibroblasts constitutively produced GM-CSF; irradiation markedly increased the production of GM-CSF. The increase in GM-CSF transcripts by irradiation was both time- and dose-dependent. Moreover, irradiation increased GM-CSF mRNA in cells with prolonged exposure to 12-O-tetradecanoyl-phorbol-13-acetate (TPA). WI38 fibroblasts constitutively produce low levels of IL-1. Induction of GM-CSF mRNA by irradiation was partially blocked by anti-IL-1 antibodies. On the other hand, inhibition of prostaglandin synthesis did not affect induction of GM-CSF RNA. Transcriptional run-on analysis showed that irradiation increased the rate of GM-CSF transcription. Stability studies of GM-CSF mRNA in these cells showed that half-life (t1/2) increased from < 20 min in unirradiated cells to > 100 min in irradiated cells. These findings suggest that the increase in GM-CSF mRNA observed after irradiation is regulated by transcriptional and post-transcriptional mechanisms. Our results indicate that induction of GM-CSF gene by irradiation requires de novo protein synthesis and increased levels of GM-CSF transcripts also occur through a pathway distinct from protein kinase C activation.
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PMID:Irradiation increases expression of GM-CSF in human fibroblasts by transcriptional and post-transcriptional regulation. 808 37


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