Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04141 (granulocyte-macrophage colony-stimulating factor)
 6,790 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) is an in vitro and in vivo stimulator of human bone marrow myelomonocytic precursor cells and mature granulocyte and macrophage effector cells. We have compared the effect of GM-CSF on the synthesis of 5-lipoxygenase products induced by the chemotactic peptide fMet-Leu-Phe and the calcium ionophore A23187 in human neutrophils. Although GM-CSF alone did not stimulate detectable synthesis of products of the 5-lipoxygenase pathway, pre-incubation of neutrophils with 200 pM GM-CSF for 1 hour at 23 degrees C enhanced synthesis of leukotriene B4, its all-trans isomers and omega-oxidation products, and 5-hydroxyeicosatetraenoic acid in response to both the calcium ionophore A23187 (1.5 microM), and the chemotactic peptide fMet-Leu-Phe (0.1 microM). This priming effect of GM-CSF was maximal after a 60 min incubation at 23 degrees C, or after a 30 min preincubation at 37 degrees C. The effect of GM-CSF was maximal using a concentration of 1 nM. Enhancement of the leukotriene synthesis stimulated by A23187 was only observed when the cells were stimulated by the ionophore for periods of 3 minutes or less. In contrast, the enhancing effect of GM-CSF was still apparent when cells were exposed to fMet-Leu-Phe for as long as 15 minutes. Furthermore, the enhancing effect of GM-CSF was ablated when neutrophils were stimulated with A23187 and exogenous arachidonic acid. However, co-addition of exogenous arachidonic acid with fMet-Leu-Phe did not entirely mask the effect of GM-CSF. Possible mechanisms of action of GM-CSF are discussed.
 ...
PMID:Characterization of the priming effects of human granulocyte-macrophage colony-stimulating factor on human neutrophil leukotriene synthesis. 314 64

Adherence of human neutrophils to plastic, fibronectin, or collagen-coated surfaces modifies their response to several agonists including granulocyte-macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor alpha (TNF-alpha), and fMet-Leu-Phe, permitting them to trigger superoxide anion (O2-) release, which they are unable to do as cells in suspension. Adherence of neutrophils causes a slight decrease in the basal level of tyrosine phosphorylation compared with that of suspended cells. The addition of GM-CSF, however, brings all proteins to a level of phosphorylation at least equal to that seen in suspended cells. In the case of a 130-kDa (p130) and a 42-kDa (p42) protein, the increase in tyrosyl phosphorylation in response to GM-CSF challenge is clearly larger in adherent than in suspended cells (6- and 4-fold increases for p130 and p42, respectively, in adherent cells vs. 1.7- and 2.1-fold in suspended cells). This is even more patient in the case of collagen-coated plates (9.4-fold increase for p42). Therefore, once neutrophils attach to surfaces, they become primed and respond to GM-CSF with greater potency than when they are in suspension. By Western blot analysis with anti-MAP kinase antibodies, we demonstrate that p42 is one member of the mitogen-activating protein kinase, namely the p42MAPK. The tyrosyl phosphorylation of p42MAPK is elevated in GM-CSF-treated adherent neutrophils in a time-dependent fashion as measured by the formation of a doublet composed of the phospho (or activated) form and the dephospho (or inactive) form of MAP kinase. MAP kinase activation and tyrosine phosphorylation are inhibited by tyrosine kinase inhibitors genistein and tyrphostin-23. Our results indicate that adherence acts to prime neutrophils for enhanced functionality and that tyrosine phosphorylation is involved in this process.
 ...
PMID:Priming of tyrosine phosphorylation in GM-CSF-stimulated adherent neutrophils. 772 26

1. Platelet-activating factor (PAF) and leukotriene B4 (LTB4), two potent lipid mediators synthesized by activated neutrophils, are known to stimulate several neutrophil functional responses. In this study, we have determined that endogenous LTB4 and PAF exert autocrine effects on LT synthesis, as well as the underlying mechanism involved. 2. Pretreatment of neutrophils with either pertussis toxin (PT), or with receptor antagonists for LTB4 and PAF, resulted in an inhibition of LT synthesis induced by calcium ionophore, A23187. This inhibition was most marked at submaximal (100-300 nM) A23187 concentrations, whilst it was least at ionophore concentrations which induce maximal LT synthesis (1-3 microM). Thus newly-synthesized PAF and LTB4 can enhance LT synthesis induced by A23187 under conditions where the LT-generating system is not fully activated. 3. In recombinant human (rh) granulocyte-macrophage colony-stimulating factor (GM-CSF)-primed neutrophils, LT synthesis in response to chemoattractants (fMet-Leu-Phe or rhC5a) was also significantly inhibited by the LTB4 receptor antagonist, and to a lesser extent by PAF receptor antagonists. 4. Further investigation revealed that LTB4 and/or PAF exert their effects on LT synthesis via an effect on arachidonic acid (AA) availability, as opposed to 5-lipoxygenase (5-LO) activation. Indeed, the receptor antagonists, as well as PT, inhibited LT synthesis and AA release to a similar extent, whereas 5-LO activation (assessed with an exogenous 5-LO substrate) was virtually unaffected under the same conditions. Accordingly, we showed that addition of exogenous LTB4 could enhance AA availability in response to chemoattractant challenge in rhGM-CSF-primed cells, without significantly affecting the 5-LO activation status. Our data show that newly-generated PAF and LTB4 have the ability to positively feedback on LT synthesis by acting at the level of the phospholipase A2/re-esterification component of the LT biosynthetic pathway in neutrophils. Such autocrine affects are likely to represent an important amplification step of LT synthesis, and may as such contribute to the rapid onset, as well as to the evolution, of inflammatory responses.
 ...
PMID:Autocrine enhancement of leukotriene synthesis by endogenous leukotriene B4 and platelet-activating factor in human neutrophils. 801 62

The effects of the cytotoxic drugs, adriamycin, cyclophosphamide, daunomycin (daunorubicin), prednisolone, actinomycin D, azacytidine and vincristine at concentrations of 1 microM on mature neutrophil function were examined. Up to 5 h incubation with adriamycin, azacytidine, cyclophosphamide, daunomycin and prednisolone had no effect on either luminol chemiluminescence or superoxide secretion. However, after 15 min or 1 h (but not 5 h) incubation vincristine enhanced fMet-Leu-Phe stimulated chemiluminescence, whilst after 5 h incubation with actinomycin D the ability of neutrophils to generate reactive oxidants in response to all stimuli tested was impaired: after 5 h incubation with adriamycin reactive oxidant production was also impaired, but only when fMet-Leu-Phe was used as stimulant. All of the drugs tested except azacytidine inhibited neutrophil oxidant production after 5 h incubation in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF). Actinomycin D and cyclophosphamide also inhibited GM-CSF stimulated protein biosynthesis. These data indicate that cytotoxic drugs may compromise the potentially beneficial effects of CSFs on mature neutrophil function during therapy.
 ...
PMID:Effect of cytotoxic drugs on mature neutrophil function in the presence and absence of granulocyte-macrophage colony-stimulating factor. 839 36

When granulocyte-macrophage colony-stimulating factor (GM-CSF)-treated human neutrophils were challenged with the chemotactic factor fMet-Leu-Phe, it was possible to detect a time-dependent increase in the hydrolytic (as measured by the production of phosphatidic acid, PA) and the transphosphatidylation (as measured by the production of phosphatidylethanol, PEt) activities of phospholipase D in intact cells prelabeled with a radioactive fatty acid. Both activities were inhibited by preincubation of cells with genistein. Appropriate conditions were developed to test the PLD transphosphatidylation activity against exogenous phosphatidylcholine (PCho) in an in vitro system. As in intact cells, increased PLD activity could be detected in cell lysates obtained from fMet-Leu-Phe-treated cells compared with controls. When lysates were immunoprecipitated with antiphosphotyrosine antibodies, a PLD activity was found only in immune complexes that were prepared from fMet-Leu-Phe-treated cells. Conversely, no activity was found in lysates immunoprecipitated with an irrelevant antibody (GTPase-activating protein, GAP) that nevertheless was able to recognize a tyrosylphosphorylated form of GAP, as demonstrated by western blotting. These data suggest that a PCho-PLD, or a tightly bound protein, is tyrosine phosphorylated during cell activation.
 ...
PMID:Immunoprecipitation of a phospholipase D activity with antiphosphotyrosine antibodies. 856 10

We have previously shown that surface levels of the adhesive glycoprotein, L-selectin, are diminished on cord blood neutrophils (polymorphonuclear leukocytes, PMN) and associated with impaired adherence to endothelium under flow conditions. To test the hypothesis that diminished surface levels reflect a total cellular deficiency, we measured L-selectin in PMN lysates and plasma from cord and adult blood. L-selectin content was decreased in cord blood PMN lysates compared with those of adults by both Western blot analyses and ELISA (cord blood, 1195 +/- 160 pg/mL; adult, 1870 +/- 260 pg/mL; X +/- SEM; p < 0.05). Soluble L-selectin levels were also decreased in cord blood plasma (324 +/- 24 ng/mL versus 537 +/- 28 ng/mLiter in adult plasma, p < 0.01). To evaluate L-selectin function, we next compared the dose dependent effect of several chemoattractants on shedding of L-selectin from cord blood and adult PMN. Adult PMN showed greater overall shedding of L-selectin as compared with cord blood PMN after stimulation with fMet-Leu-Phe (p < 0.03) and granulocyte-macrophage colony-stimulating factor (p < 0.02). In contrast, shedding of L-selectin was similar between groups after IL-8 tested stimulation. We conclude that cord blood PMN have a decreased cellular content of L-selectin in addition to an impaired ability to shed surface L-selectin in response to specific inflammatory mediators.
 ...
PMID:Diminished soluble and total cellular L-selectin in cord blood is associated with its impaired shedding from activated neutrophils. 884 34

The effects of soluble and particulate agonists on the tyrosine phosphorylation levels of the proto-oncogene Cbl in human neutrophils were examined. Experimental conditions allowing the maintenance of Cbl as well as of its tyrosine phosphorylation status were first established. Their use allowed us to observe that Cbl was tyrosine phosphorylated in response to some (FcgammaRII ligation, opsonized bacteria and zymosan, granulocyte-macrophage colony-stimulating factor, monosodium urate, and calcium pyrophosphate microcrystals), but not all (fMet-Leu-Phe, interleukin-8) neutrophil agonists. Cbl was also shown to account for a varying proportion of the 120-kDa phosphoprotein(s) observed in response to the above stimuli. These data establish that Cbl is present in human neutrophils and that its level of tyrosine phosphorylation is modulated by some of these cells' agonists, and in particular by phagocytic particles. Furthermore, the signaling pathways activated by chemotactic factors and the other neutrophil stimuli tested in this investigation diverge at or downstream from the tyrosine phosphorylation of Cbl.
 ...
PMID:Agonist-specific tyrosine phosphorylation of Cbl in human neutrophils. 940 Aug 33

The small GTPase Rap1 is highly expressed in human neutrophils, but its function is largely unknown. Using the Rap1-binding domain of RalGDS (RalGDS-RBD) as an activation-specific probe for Rap1, we have investigated the regulation of Rap1 activity in primary human neutrophils. We found that a variety of stimuli involved in neutrophil activation, including fMet-Leu-Phe (fMLP), platelet-activating factor (PAF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and IgG-coated particles, induce a rapid and transient Rap1 activation. In addition, we found that Rap1 is normally activated in neutrophils from chronic granulomatous disease patients that lack cytochrome b558 or p47phox and have a defective NADPH oxidase system. From these results we conclude that in neutrophils Rap1 is activated independently of respiratory burst induction. Finally, we found that Rap1 is activated by both the Ca2+ ionophore ionomycin and the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA), indicating that phospholipase C (PLC) activation leading to elevated levels of intracellular free Ca2+ and diacylglycerol (DAG) can mediate Rap1 activation. However, inhibition of PLC and Ca2+ depletion only marginally affected fMLP-induced Rap1 activation, suggesting that additional pathways may control Rap1 activation.
 ...
PMID:Activation of the small GTPase rap1 in human neutrophils. 973 Oct 72

An influx of neutrophils into the airways is a common feature observed during pulmonary inflammation induced by air pollutants, including sulfur dioxide and sulfates. In the present study focusing on the in vitro interactions of sodium sulfite (Na2SO3) with human neutrophils, we confirm results indicating that this sulfite induces superoxide production (O2-) by itself. We demonstrated that this response can occur more rapidly than previously reported (within 5 min), and that Na2SO3 can act as a priming agent, in a concentration-dependent fashion, to the bacterial tripeptide N-formyl-methionine-leucine-phenylalanine (fMLP) by increasing O2-production. In addition, our results show that Na2SO3 induces gene expression in human neutrophils in a concentration-dependent manner as assessed by incorporation of 5-[3H] uridine into total RNA. However, it does not induce cell shape changes. We also demonstrated that Na2SO3 does not modulate neutrophil apoptosis nor reverse the well-known delaying effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on apoptosis. We conclude that Na2SO3 acts rapidly on neutrophil physiology, within a few minutes with respect to superoxide production, and a few hours (4 h) with respect to gene expression without altering a biological process such as the rate of apoptosis evaluated after a long period of incubation (20 h). We further conclude that Na2SO3-induced production of O2does not drive neutrophils to undergo apoptosis, a mechanism known to occur in other conditions. Therefore, the potential toxicity of Na2SO3 during pulmonary inflammation or lung-associated diseases may be related to its ability to induce superoxide production without altering neutrophil apoptosis rate.
 ...
PMID:Functional responses of human neutrophils to sodium sulfite (Na2SO3) in vitro. 986 16

When the hematopoietic growth factor granulocyte-macrophage colony-stimulating factor was incubated with neutrophils adherent to plastic tissue culture plates or plates coated with extracellular matrix proteins, a rapid (3 min) but transient formation of phosphatidic acid was observed. This stimulation was dependent on the dose of GM-CSF, with an EC50 of 140 pM, and was further enhanced (up to 350%) with the PA phosphatase inhibitor propranolol in a dose-dependent manner. Conversely, GM-CSF was unable to trigger any PA formation in neutrophils maintained in suspension, even in the presence of soluble fibronectin. However, GM-CSF did prime the cells for enhanced PA formation in the presence of a secondary stimulus (fMet-Leu-Phe or PAF). GM-CSF also caused a time-dependent stimulation of diacylglycerol formation in adherent, but not suspended, cells and elicited a time-dependent stimulation of phosphatidylethanol formation, with a concomitant decrease in the formation of PA only at early (< 7 min) times. These observations were consistent with a rapid activation of the enzyme phospholipase D in adherent cells stimulated with GM-CSF. Additional data indicated that the source of DAG was PLD coexisting with PLC, especially at later times ( > 7 min) of stimulation with GM-CSF. Finally, the formation of PA and PEt, and to a minor extent, DAG, were inhibited by the protein tyrosine kinase inhibitor erbstatin in conditions in which tyrosine phosphorylation occurred. Taken together the data indicate that GM-CSF rapidly activates PLD in adherent cells, which is responsible for the generation of PA. Thus, PLD activation is an early event in neutrophil signal transduction following exposure of adherent cells to GM-CSF.
 ...
PMID:Binding of GM-CSF to adherent neutrophils activates phospholipase D. 1035 94


<< Previous 1 2 3 Next >>