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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)
The antimalignant cell activity of tumor necrosis factor (TNF) in many cell types can be enhanced by lithium chloride (LiCl). This study shows the in vitro effect of LiCl on the TNF-induced or interleukin 1 (IL-1)-induced expression of IL-6,
granulocyte-macrophage colony-stimulating factor
(
GM-CSF
), IL-3, IL-2, and the IL-2 receptor-alpha (IL-2R alpha). The levels of IL-6 and
GM-CSF
in the medium of TNF-treated L929 fibrosarcoma cells were increased by cotreatment with LiCl. In contrast, enhancement of IL-6 production by dibutyryl cyclic
AMP
or cycloheximide was not affected by LiCl. The production of IL-6 and
GM-CSF
was not correlated with sensitivity to TNF-mediated cell killing. IL-1 by itself had no measurable effects on L929 cells. However, LiCl potentiated the IL-1-induced synthesis of IL-6,
GM-CSF
, IL-3, and IL-2 in PC60 murine T-cell hybridoma cells. TNF alone induced only
GM-CSF
production in these cells, but in the presence of LiCl, increased amounts of
GM-CSF
as well as small amounts of IL-2 and IL-6 could be detected. It is also shown that in these PC60 cells the expression of the IL-2R alpha was induced by TNF + LiCl treatment but not by TNF alone. IL-2R alpha expression was likewise considerably enhanced by IL-1 + LiCl treatment, as compared with treatment with IL-1 alone. The effects of LiCl on the TNF-induced and the IL-1-induced gene expression seem to be independent of the protein kinase A and C pathways. These results show that LiCl can modulate both TNF-mediated cytotoxicity and TNF-induced and IL-1-induced cytokine expression, suggesting that Li+ acts early in the TNF-signaling pathway, but at a step shared with the IL-1-signaling pathway.
...
PMID:Lithium chloride potentiates tumor necrosis factor-induced and interleukin 1-induced cytokine and cytokine receptor expression. 165 81
Granulocyte colony-stimulating factor(G-CSF) and
granulocyte-macrophage colony-stimulating factor
(
GM-CSF
) increased neutrophil C3bi-receptor expression and adherence and rapidly (less than 10 min) primed neutrophils to enhanced O2- release and membrane depolarization stimulated by chemotactic peptide. Direct triggering of O2- release in suspended neutrophils was also provoked by
GM-CSF
but not by G-CSF.
GM-CSF
-induced O2- release was inhibited by cyclic
AMP
agonists and cytochalasin B. The biological activity was greater in non-glycosylated
GM-CSF
than in glycosylated
GM-CSF
, whereas it was identical in glycosylated and non-glycosylated G-CSFs. Direct stimulation and priming by
GM-CSF
were consistently greater than those by G-CSF and the combined addition of the optimal concentrations of G-CSF and
GM-CSF
resulted in the effects of
GM-CSF
alone. These findings indicate that the effects of G-CSF and
GM-CSF
on neutrophil functions are qualitatively and quantitatively different from each other.
...
PMID:Stimulation and priming of human neutrophils by granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor: qualitative and quantitative differences. 169 66
Human recombinant interleukin-4 (IL-4) was studied for its effects on the expression of granulocyte-colony stimulating factor (G-CSF) mRNA in human adherent monocytes in the absence and presence of endotoxin and interleukin 1 (IL-1). IL-4 (15 ng/ml) did not induce G-CSF transcripts in monocytes but suppressed the endotoxin-induced G-CSF expression when added simultaneously. Sequential treatment of monocytes with IL-4 followed by endotoxin suppressed G-
CSF mRNA
induction totally. This effect was independent of the presence of fetal bovine serum but dependent of the IL-4 dose. Comparable results were obtained with IL-1. IL-1 (50 U/ml) induced G-CSF expression in human adherent monocytes which could be counteracted by IL-4 pretreatment. In addition, it was shown that the induction of G-
CSF mRNA
by the calcium-ionophore A23187 or by c-
AMP
elevating agents could be blocked by IL-4. These suppressive effects of IL-4 were not related to changes in the half-life of G-
CSF mRNA
and were independent of protein synthesis. Finally it was demonstrated that IL-4 had comparable effects on the G-CSF secretion of endotoxin and IL-1 stimulated human monocytes by using a murine bone marrow assay. These results indicate that IL-4 down-regulates the expression of G-CSF gene and secretion of proteins in human activated monocytes.
...
PMID:Interleukin-4 prevents the induction of G-CSF mRNA in human adherent monocytes in response to endotoxin and IL-1 stimulation. 171 62
Interleukin-8 (IL-8) stimulated an increase in cytoplasmic-free Ca2+ ([Ca2+]i) and intracellular pH (pHi) in parallel at low concentrations (0.5 to 5 ng/mL), and stimulated O2- release and membrane depolarization in parallel at high concentrations (50 to 5,000 ng/mL). IL-8-induced O2- release was potentiated by tumor necrosis factor (TNF),
granulocyte-macrophage colony-stimulating factor
(
GM-CSF
), and granulocyte-CSF (G-CSF) in a dose-dependent manner, whereas it was inhibited by cyclic
AMP
agonists. These characteristics and the time-courses of the responses stimulated by IL-8 were similar to those stimulated by N-formyl-methionyl-leucyl-phenylalanine (FMLP), except that the cells stimulated by IL-8 showed shorter duration and less magnitude in some responses. In addition, IL-8 was found to be a potent priming agent and to enhance O2- release stimulated by FMLP. The priming effect of IL-8 was very rapid and was maximal within 5 minutes of preincubation. The dose-response curves for priming were identical to those for triggering of an increase in [Ca2+]i and pHi. The potency of the maximal priming effects on FMLP-induced O2- release was TNF greater than
GM-CSF
greater than IL-8 greater than G-CSF. The combination of IL-8 and the suboptimal concentrations of TNF or
GM-CSF
resulted in the additive priming effect, whereas the combination of the optimal concentration of IL-8 and the optimal concentration of TNF,
GM-CSF
, or G-CSF resulted in the effect of more potent priming agent alone. These findings suggest that IL-8 stimulates or primes human neutrophils according to its concentrations and cross-talks with TNF,
GM-CSF
, G-CSF, or FMLP at the inflammatory sites.
...
PMID:Stimulation and priming of human neutrophils by interleukin-8: cooperation with tumor necrosis factor and colony-stimulating factors. 172 9
The promoter of the human
granulocyte-macrophage colony-stimulating factor
gene is regulated by an inducible upstream enhancer. The enhancer encompasses three previously defined binding sites for the transcription factor NFAT (GM170, GM330, and GM550) and a novel NFAT site defined here as the GM420 element. While there was considerable redundancy within the enhancer, the GM330, GM420, and GM550 motifs each functioned efficiently in isolation as enhancer elements and bound NFATp and AP-1 in a highly cooperative fashion. These three NFAT sites closely resembled the distal interleukin-2 NFAT site, and methylation interference assays further defined GGA(N)9TCA as a minimum consensus sequence for this family of NFAT sites. By contrast, the GM170 site, which also had conserved GGA and TCA motifs but in which these motifs were separated by 15 bases, supported strong independent but no cooperative binding of AP-1 and NFATp, and this site functioned poorly as an enhancer element. While both the GM330 and GM420 elements were closely associated with the inducible DNase I-hypersensitive site within the enhancer, the GM420 element was the only NFAT site located within a 160-bp HincII-BalI fragment defined by deletion analysis as the essential core of the enhancer. The GM420 element was unusual, however, in containing a high-affinity NFATp/c-binding sequence (TGGAAAGA) immediately upstream of the sequence TGACATCA which more closely resembled a cyclic
AMP
response-like element than an AP-1 site. We suggest that the cooperative binding of NFATp/c and AP-1 requires a particular spacing of sites and that their cooperativity and induction via independent pathways ensure very tight regulation of the
granulocyte-macrophage colony-stimulating factor
enhancer.
...
PMID:Human granulocyte-macrophage colony-stimulating factor enhancer function is associated with cooperative interactions between AP-1 and NFATp/c. 789 2
Granulocyte-macrophage colony-stimulating factor
(
GM-CSF
) stimulates myeloid progenitor cell proliferation and enhances the function of terminally differentiated effector cells. Interleukin-3 (IL-3) stimulation results in the proliferation and maturation of early bone marrow progenitor cells. These activities are mediated by non-tyrosine kinase-containing receptors which consist of ligand-specific alpha subunits that complex with a common beta subunit required for signal transduction. Both
GM-CSF
and IL-3 rapidly and transiently induce expression of early growth response gene 1 (egr-1) in the human factor-dependent cell line TF-1. To define the mechanism of early response gene induction by
GM-CSF
and IL-3, growth factor- and serum-starved TF-1 cells transfected with recombinant constructs containing sequences of the human egr-1 promoter were stimulated with
GM-CSF
or IL-3. A 116-nucleotide (nt) region of the egr-1 promoter which contains sequences inducible by
GM-CSF
and IL-3 was defined. DNase I footprint analysis identified a 20-nt region, including nt -57 to -76, which contains a potential cyclic
AMP
(cAMP) response element (CRE). Electrophoretic mobility shift assays performed with CREB antibody confirmed the presence of CREB in the DNA-binding complex. Mutational analysis of the cytokine-responsive region of the egr-1 promoter revealed that both the cAMP response and serum response elements are required for induction by
GM-CSF
and IL-3. Nuclear extracts from
GM-CSF
- or IL-3-stimulated but not unstimulated TF-1 cells contain factors which specifically bind to the Egr-1-binding site in the nt -600 to -480 region of the promoter. Electrophoretic mobility shift assays were performed with antibodies against the Egr-1 protein to demonstrate the presence of the protein product in the shifted complex. Our studies suggest that the Egr-1 protein may further stimulate transcription of the egr-1 gene in response to
GM-CSF
as a secondary event.
...
PMID:Granulocyte-macrophage colony-stimulating factor and interleukin-3 signaling pathways converge on the CREB-binding site in the human egr-1 promoter. 806 30
Studies with the
granulocyte-macrophage colony-stimulating factor
(
GM-CSF
)/interleukin-3 (IL-3) fusion protein, PIXY321, demonstrated enhanced biological activity of this molecule in comparison with
GM-CSF
or IL-3 alone or in combination. Experiments were performed to study the mechanisms resulting in PIXY321-induced egr-1 expression in human myeloid leukemic cells (TF-1). Transfections of egr-1 promoter constructs revealed that PIXY321 stimulation resulted in fourfold induction of the -116 and -600 nucleotide (nt) constructs. We transfected a -116 nt construct containing a deletion of the cyclic
AMP
response element (CRE) or mutation in the serum response element (SRE) and demonstrated that both the SRE and CRE are necessary for maximal induction. However, PIXY321 stimulation resulted in 2.5-fold induction of a SRE-CRE-containing construct (P < .05), suggesting that the SRE and CRE are sufficient for PIXY321 responsiveness. Electrophoretic mobility shift assays (EMSA) revealed that the CRE binding protein (CREB) was phosphorylated on serine 133 in PIXY321-stimulated but not -unstimulated extracts from cells cultured in
GM-CSF
. By Western analysis and EMSA, CREB was constitutively phosphorylated in TF-1 cells grown on PIXY321 before growth factor and serum starvation. However, in TF-1 cells grown on
GM-CSF
before starvation, CREB phosphorylation was observed 10 minutes after PIXY321 stimulation. Further-more, ENSAs with PIXY321-stimulated and -unstimulated extracts demonstrated the presence of specific proteins that recognize the SRE. Our data demonstrate that transcriptional regulation of egr-1 by PIXY321 is mediated by the CRE and SRE.
...
PMID:Mechanism of transcriptional activation of the immediate early gene Egr-1 in response to PIXY321. 870 40
Bone marrow (BM) stromal cells are required for normal hematopoiesis. A number of soluble factors secreted by these cells that mediate hematopoiesis have been characterized. However, the mechanism of hematopoiesis cannot be explained solely by these known factors, and the existence of other, still unknown stromal factors has been postulated. We showed that hepatocyte growth factor (HGF) is one such cytokine produced by human BM stromal cells. BM stromal cells were shown to constitutively produce HGF and also to express the c-MET/HGF receptor. The production of HGF was enhanced by addition of heparin and phorbol ester. Dexamethasone and tumor growth factor-beta (TGF-beta) inhibited the production of HGF. Interleukin-1 alpha (IL-1 alpha) tumor necrosis factor-alpha (TNF-alpha), and N6,2'-o-dibutyryl-adenosine-3':5'-cyclic monophosphate (dbc-
AMP
) showed no obvious influence on HGF production. Western blot analysis of HGF derived from BM stromal cells showed two bands at 85 and 28 kD corresponding to native and variant HGF, respectively. Addition of recombinant HGF significantly promoted the formation of burst-forming unit-erythroid (BFU-E) and colony-forming unit-granulocyte erythroid macrophage (CFU-GEM) by BM mononuclear cells in the presence of erythropoietin and
granulocyte-macrophage colony-stimulating factor
(
GM-CSF
), but the formation of CFU-GM was not modified. However, HGF had no effects on colony formation by purified CD34+ cells. Within BM mononuclear cells, c-MET was expressed on a proportion of cells (CD34-, CD33+, CD13+, CD14+, and CD15+), but was not found on CD34+ cells. We conclude that HGF is constitutively produced by BM stromal cells and that it enhances hematopoiesis. In addition, expression of c-MET on the stromal cells suggests the presence of an autocrine mechanism, operating through HGF, among stromal cells.
...
PMID:Hepatocyte growth factor is constitutively produced by human bone marrow stromal cells and indirectly promotes hematopoiesis. 905 37
In a recent study, we showed that
granulocyte-macrophage colony-stimulating factor
(
GM-CSF
) and supernatants from partially stimulated platelets undergoing selective alpha-granule release synergistically enhanced polymorphonuclear leukocyte (PMN) response to N-formyl-methionyl-leucyl-phenylalanine (fMLP). The active factor released from platelet alpha-granules was identified as platelet factor four (PF4). In this study we investigate the joint effect on PMN reactivity of
GM-CSF
and supernatants from platelets maximally stimulated to release both alpha- and dense granule contents. These platelet supernatants enhanced PMN chemiluminescence (CL; a measure of the oxidative burst) during short incubations, whereas longer incubations led to the loss of this enhancement and the prevention of PMN priming by
GM-CSF
. The platelet-derived inhibitory factor was of low molecular weight, originated from the dense granule precursor(s), and its generation required the presence of PMN. When ATP/ADP were incubated with PMN at concentrations found in platelet-dense granules, they produced a similar biphasic effect on PMN reactivity (a potentiation followed by inhibition) as seen with the platelet supernatants. The inhibitory effect of these nucleotides coincided with their conversion to
AMP
.
AMP
per se had an immediate inhibitory effect on PMN response to fMLP and prevented PMN priming by
GM-CSF
. This study confirms that partially stimulated platelets enhance PMN reactivity. However, during maximal stimulation, nucleotides released from the platelet-dense granules are converted to
AMP
, which in turn can counteract the PMN priming effects of factors such as PF4 and
GM-CSF
.
...
PMID:Sequential potentiation and inhibition of PMN reactivity by maximally stimulated platelets. 906 Apr 55
Prostacyclin (prostaglandin I2, PGI2) is a potent vasodilator and inhibitor of platelet aggregation. Although it is well known that the specific receptor for prostacyclin (PGI2-R) is abundantly expressed on platelets, PGI2-R expression in megakaryocytes is poorly understood. In this study, we examined its expression in leukemic or normal megakaryocytes. PGI2-R mRNA was expressed in human leukemic cell lines of megakaryocytic nature as evaluated by Northern blot analysis. Phorbol 12-myristate 13-acetate (PMA), interleukin-1 (IL-1), IL-3, IL-6,
granulocyte-macrophage colony-stimulating factor
(
GM-CSF
), thrombopoietin (TPO), and tumor necrosis factor-alpha (TNF-alpha) enhanced PGI2-R mRNA expression. The enhancement of PGI2-R expression by PMA and TPO was associated with the upregulation of platelet factor 4 or glycoprotein IIb mRNA expression. Iloprost, an agonist of prostacyclin, induced significant cyclic (c)
AMP
synthesis in these leukemic cells indicating that interaction of PGI2-R and its ligand can induce postreceptor signal transduction. Furthermore, iloprost-induced cAMP synthesis was enhanced by the pretreatment with PMA or the cytokines that promoted PGI2-R expression. PMA and TPO also increased the specific binding of [3H]iloprost to these cells. Pooled normal megakaryocytic colonies from TPO-containing semisolid culture of purified human CD34+ cells expressed PGI2-R, which were increased as the megakaryocytes matured with the peak expression before proplatelet formation, as evaluated by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). These results indicate that PGI2-R is expressed in human megakaryocytes and is upregulated by cytokines involved in thrombopoiesis or inflammation. Also, it was indicated that megakaryocytic maturation accompanies enhancement of PGI2-R expression.
...
PMID:Expression of prostacyclin receptor in human megakaryocytes. 924 34
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