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)

1. The addition of 2 x 10(8) human platelets to 8 x 10(6) polymorphonuclear leucocytes (PMNL) incubated in presence of 2.5 u ml-1 thrombin and 0.1 microM N-formyl-Met-Leu-Phe (FMLP) (or C5a or PAF) led to enhancement of leukotriene B4 (LTB4) synthesis by the PMNL (measured by h.p.l.c. as 20-hydroxy- and 20-carboxy-LTB4) from 4 +/- 1 pmol (in absence of platelets) to 26 +/- 4 pmol (mean +/- s.e.mean, n = 9). Platelets and thrombin were both essential for the enhancement of LTB4 synthesis. 2. Platelets also caused enhancement of LTB4 synthesis from (30 +/- 12 to 134 +/- 25 pmol, n = 6) when PMNL pretreated with granulocyte-macrophage colony-stimulating factor were used in similar experiments. 3. Enhancement of LTB4 synthesis was also observed (from 5 +/- 1.5 to 26.5 +/- 5 pmol, n = 9) when the supernatants of thrombin-activated platelet suspensions were added to FMLP-stimulated PMNL. 4. Supernatants of platelet suspensions activated by thrombin in presence of cyclo-oxygenase and 12-lipoxygenase inhibitors led to greater enhancement (from 5 +/- 3 to 153.5 +/- 27.5 pmol, n = 3) of LTB4 synthesis by FMLP-stimulated PMNL, suggesting that arachidonic acid itself, rather than its metabolites was responsible for the effects of platelets. 5. Addition of arachidonic acid to FMLP-stimulated PMNL at a concentration comparable to that measured in thrombin-activated platelet supernatants (0.2 +/- 0.025 microM, n = 6) mimicked the effect of platelets or platelet supernatants on LTB4 synthesis in FMLP-activated PMNL. 6. The present data indicate that under conditions of cell activation by physiological agonists, platelets can significantly increase the formation of the proinflammatory compound LTB4 in PMNL by providing arachidonic acid. These data lend support to the concept that platelet-PMNL interactions could modulate the inflammatory process.
 ...
PMID:Thrombin-activated platelets promote leukotriene B4 synthesis in polymorphonuclear leucocytes stimulated by physiological agonists. 165 46

The hematopoietic growth factors, granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF), enhance the effector functions of mature myeloid cells, including the interaction with vascular endothelium. We examined the direct effect of recombinant human GM-CSF (rhGM-CSF) and recombinant human G-CSF (rhG-CSF) on the growth and function of cultured human umbilical vein endothelial cells (HUVEC). Endothelial cell growth supplement (ECGS) increased the proliferation of passaged and primary cells by 305% +/- 45% (mean +/- SEM, n = 5, P less than .01) over control cells at 4 days; GM-CSF and G-CSF had no effect. Endothelial cell procoagulant activity was increased after 4-hour incubation with recombinant interleukin-1 beta (IL-1 beta) 10 U/mL and recombinant tumor necrosis factor (TNF) 10 U/mL to 1,721% +/- 376% (n = 7, P less than .005) and 247% +/- 71% (n = 4) of control levels, respectively. gamma-Interferon (gamma-IFN) 50 U/mL had no direct effect of its own but was able to prime the response to IL-1 beta. There was no direct or priming effect of GM-CSF (1 ng to 1 microgram/mL) on the expression of procoagulant activity in endothelial cells. GM-CSF and G-CSF (1 ng/mL to 1 microgram/mL) had no effect on the expression of either tissue plasminogen activator (tPA) or plasminogen activator inhibitor-1 (PAI-1) by endothelial cells. The secretion of tPA by endothelial cells was increased, however, after 24-hour incubation with thrombin 4 U/mL (314% +/- 72% of control levels, n = 5, P less than .025). The production of PAI-1 was increased by TNF 200 U/mL (241% +/- 44% of control, n = 3, P less than .005), thrombin 4 U/mL (180% +/- 12% of control, n = 5, P less than .0005) and IL-1 beta 10 U/mL (275% +/- 44% of controls, n = 5, P less than .0005). In four experiments, endothelial cells showed no specific binding of 125I-GM-CSF, whereas peripheral blood (PB) neutrophils demonstrated the presence of 802 +/- 78 high-affinity receptors for GM-CSF. Thus, we found no effect of rhGM-CSF or rhG-CSF on the proliferation activities by these cells. These findings are in accordance with the lack of demonstrable receptors for GM-CSF on cultured HUVEC.
 ...
PMID:Lack of effect of granulocyte-macrophage and granulocyte colony-stimulating factors on cultured human endothelial cells. 193 61

The presence of heterogeneous erythroid progenitor cells, contaminant cells, or serum may alter erythroid colony development in vitro. To obtain highly purified colony-forming units-erythroid (CFU-E), we cultured partially purified human blood burst-forming units-erythroid (BFU-E) in methylcellulose with recombinant human erythropoietin (rHuEPO) for 7 d and generated cells that consisted of 30-60% CFU-E, but no BFU-E. A serum-free medium was used that allowed development of the same number of erythroid colonies as serum containing medium, but with a greater percentage of larger colonies. This medium consisted of delipidated crystalline bovine serum albumin, iron saturated transferrin, lipid suspension, fibrinogen, thrombin, Iscove's modified Dulbecco's medium/F-12[HAM], and insulin plus rHuEPO. When CFU-E were cultured in a limiting dilution assay and the percentage of nonresponder wells was plotted against cell concentration, both serum-free cultures and serum-containing cultures yielded overlapping straight lines through the origin indicating that CFU-E development did not depend on accessory cells and that insulin acted directly on the CFU-E. Human recombinant interleukin 3 (IL-3) and/or granulocyte-macrophage colony-stimulating factor had no effect on CFU-E growth, while they markedly enhanced BFU-E growth. Physiological concentrations of recombinant human insulin-like growth factor I (IGF-I) enhanced CFU-E growth in the absence of insulin and, together with rHuEPO in serum-free medium, provided a plating efficiency equal to that of serum-containing medium. Limiting dilution analysis in serum-free medium with IGF-I showed a straight line through the origin indicating that IGF-I also acted directly on the CFU-E and not through an effect on accessory cells. These data demonstrate that CFU-E do not require accessory cells, but do require IGF-I and/or insulin which act directly on the CFU-E.
 ...
PMID:Human colony-forming units-erythroid do not require accessory cells, but do require direct interaction with insulin-like growth factor I and/or insulin for erythroid development. 265 78

Human erythroid progenitor cells were isolated from peripheral blood of healthy donors and amplified in a suspension culture system using recombinant growth factors (stem cell factor, interleukin-3, granulocyte-macrophage colony-stimulating factor and erythropoietin) as well as conditioned medium from a human bone marrow stroma cell line to support cell proliferation. After 6-8 days of culture, the cell population consisted mainly of erythroid colony-forming cells (burst-forming units, BFU-Es and colony-forming units, CFU-Es). In these cells, we studied ligand-induced changes in intracellular Ca2+ concentration ([Ca2+]i) and cAMP formation as the primary effector systems of guanine nucleotide-binding protein (G protein)-coupled receptors. The results confirmed the functional expression of receptors for adenosine (type A2B), prostaglandin E1 and isoprenaline (beta-adrenoceptor), all of which stimulated adenylyl cyclase, as well as for ADP (purinoceptor types P2T and P2U), platelet-activating factor and thrombin all of which caused a transient increase in [Ca2+]i. The efficacy of adenosine and prostaglandin E1 in stimulating cAMP formation was more than 5 times higher than that of isoprenaline, suggesting a low beta-adrenoceptor density. The response to adenosine and isoprenaline decreased by 80 and 55% respectively during maturation into the proerythroblast stage. Similarly, thapsigargin-sensitive intracellular Ca2+ stores and ligand-induced Ca2+ release declined by about 60% during the CFU-E-to-erythroblast transition. The overall functional expression pattern of G protein-coupled receptors differed from that in human erythroleukaemia cell lines or from that in platelets. Primary culture systems for nontransformed cells, such as the one presented here, thus will be indispensable for the study of the functional role of G protein-dependent signalling during haematopoiesis.
 ...
PMID:G-protein-coupled receptors in normal human erythroid progenitor cells. 875 Sep 11

We studied the effects of serine proteases on cytokine gene expression by cultured normal human keratinocytes. In resting keratinocytes, steady-state mRNA levels for interleukins IL-1 alpha, IL-1 beta, IL-7, and IL-8, transforming growth factors alpha and beta, and tumor necrosis alpha were sufficient to be detected by our reverse transcriptase-polymerase clozin reaction method. Incubation of keratinocytes with 25 nM trypsin or 1 unit/ml thrombin for 24 hr selectively upregulated mRNA levels for granulocyte-macrophage colony-stimulating factor (GM-CSF) and Il-6 to detectable levels. Keratinocytes secreted GM-CSF and IL-6 protein in response to these proteases. Monensin did not inhibit the gene expression for the cytokines, thereby excluding the possibility of intervention by secreted molecules. Aprotinin and argatroban inhibited the effects of the proteases. SFLLRN and SLIGRL, tethered ligand receptor peptides for thrombin receptor and for proteinase-activated receptor 2 (PAR-2), respectively, duplicated the effects of the proteases on keratinocytes, which expressed mRNA for both receptors. Trypsin increased tyrosine phosphorylated proteins and intracellular free calcium concentrations. Tyrphostin, pertussis toxin, or H-7 suppressed trypsin- and thrombin-induced GM-CSF gene expression. Our results demonstrate that the serine proteases activate thrombin receptors and PAR-2 on keratinocytes, triggering intracellular signaling and then inducing the synthesis of GM-CSF. We speculate that serine proteases modulate the course of physiological and pathological processes in the skin by stimulating keratinocytes to produce the cytokines.
 ...
PMID:Thrombin and trypsin induce granulocyte-macrophage colony-stimulating factor and interleukin-6 gene expression in cultured normal human keratinocytes. 906 88

(1) Thrombin, a mitogen for human cultured airway smooth muscle (HASM), has many actions that have been attributed to activation of protease-activated receptor (PARs). However, the role of PARs in the proliferative action has not been clearly identified. Moreover, thrombin elicits cytokine production in a number of cell types, but these effects have not been characterized in human ASM. (2) Thrombin (0.03-3 U ml(-1))-stimulated increases in the levels of the pro-inflammatory and fibrogenic cytokine, granulocyte-macrophage colony-stimulating factor (GM-CSF) were observed over the same concentration range observed for thrombin-stimulated mitogenesis. (3) Inhibition of thrombin proteolytic activity, with either D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone (PPACK)- or hirudin-treated thrombin (0.3 U ml(-1)) or in the presence of the thrombin serine protease-selective inhibitor, SDZ 217-766 (0.15 micro M), reduced the thrombin-stimulated GM-CSF levels by 91+/-3, 65+/-12 and 83+/-9% (n=8, P<0.05), respectively. PPACK treatment, hirudin and SDZ 217-766 inhibited thrombin-stimulated increase in cell number by 70+/-8, 63+/-11 and 69+/-8%, respectively. (4) PAR-selective peptides SFLLRN (PAR1; 10 micro M), SLIGKV (PAR2; 10 micro M), GYPGQV (PAR4; 100 micro M) or the combination of SFLLRN and GYPGQV elicited mitogenic responses of only 15% of that to thrombin and surprisingly, had no effect on GM-CSF levels (n=8). Nevertheless, inhibition of thrombin responses by pertussis toxin (50 ng ml(-1)) suggests that the PAR-independent actions also involve a G-protein-coupled receptor. (5) PAR1 receptor expression was evident by immunohistochemistry and these receptors were coupled to increases in intracellular calcium, but not to the phosphorylation of ERK or the increases in cyclin D1 protein levels that are essential for cell proliferation. Cross-desensitization of intracellular calcium increases by thrombin and the PAR1-selective peptide provides evidence that the PAR1 receptor responds to both ligands. (6) The failure of PAR-selective peptides to mimic thrombin responses together with the inhibition of thrombin responses by serine protease inhibitors suggest the involvement of novel proteolytic receptor targets for thrombin-induced mitogenesis and cytokine production.
 ...
PMID:Protease-activated receptor (PAR)-independent growth and pro-inflammatory actions of thrombin on human cultured airway smooth muscle. 1264 88

Glucocorticoids (GCS) inhibit mitogenesis of airway smooth muscle (ASM) cells grown on plastic. We have now evaluated the effects of GCS on proliferation of ASM grown on extracellular matrix proteins (ECM) abundant in noninflamed airways (laminin) and in fibrotic asthmatic airways (collagen type I). Dexamethasone inhibited basic fibroblast growth factor (bFGF)-induced proliferation in cells maintained on laminin, but not collagen. Cells grown on collagen were resistant to the anti-mitogenic actions of fluticasone propionate. In addition, dexamethasone did not inhibit thrombin-induced proliferation. Thus, resistance induced by collagen is not dependent on the mitogen and appears to be a class effect on GCS. The inhibition of bFGF-induced granulocyte-macrophage colony-stimulating factor production was unaffected by the ECM type on which cells were grown. The impaired anti-mitogenic activity of GCS in cells maintained on collagen may be due to a lack of efficacy against the collagen-amplified mitogenesis, rather than any defect in responsiveness that is specific to glucocorticoid receptor mechanisms.
 ...
PMID:Collagen-induced resistance to glucocorticoid anti-mitogenic actions: a potential explanation of smooth muscle hyperplasia in the asthmatic remodelled airway. 1271 13

Protease-activated receptors (PARs) are stimulated by proteolytic cleavage of their extracellular domain, unmasking a new N-terminus acting as tethered ligand. Whereas the role of PARs in platelets is well known, their presence and function in human monocytes and other antigen-presenting cells has not been characterized. Here it is demonstrated that human peripheral monocytes and monocyte-derived macrophages and dendritic cells differentially express PARs. Human monocytes express mainly PAR1 and less PAR3. Differentiation of monocytes into macrophages by either macrophage colony-stimulating factor (M-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF) elicits enhanced expression of PAR1, PAR2, and PAR3. In contrast, dendritic cells differentiated from monocytes by GM-CSF and interleukin-4 (IL-4) strongly down-regulated PAR1, PAR2, and PAR3, both at the mRNA and the protein level. Down-regulation of the PAR expression was apparently due to IL-4, because treatment of macrophages with IL-4 caused down-regulation of PAR1, PAR2, and PAR3. PAR4 mRNA expression remained undetectable in any of the cell types investigated. Stimulation of PAR1, PAR2, and PAR3 with thrombin, trypsin, or established receptor-activating peptides (PAR-APs) triggered cytosolic Ca2+ responses, indicating functionally active PARs. Further, stimulation of monocytes or macrophages with thrombin or PAR1-AP, but not with PAR2-or PAR4-AP, triggers expression of monocyte chemoattractant protein-1 (MCP-1) both at the mRNA and the protein level. These data demonstrate that differentiation of human monocytes is associated with differential expression of functionally active PARs that mediate distinct regulatory functions in inflammation and atherogenesis.
 ...
PMID:Differential expression and regulation of protease-activated receptors in human peripheral monocytes and monocyte-derived antigen-presenting cells. 1280 69

For a subpopulation of asthmatics, symptoms persist even with high doses of glucocorticoids. Glucocorticoids reduce the levels of the proinflammatory and fibrogenic cytokine, granulocyte-macrophage colony-stimulating factor (GM-CSF) produced by human cultured airway smooth muscle (ASM). We have contrasted the effects of a synthetic glucocorticoid, dexamethasone, on thrombin- and IL-1alpha-stimulated GM-CSF production in human ASM cells. Although IL-1alpha stimulated three-fold higher levels of GM-CSF mRNA and protein compared to thrombin, dexamethasone concentration-dependently reduced IL-1alpha-stimulated GM-CSF more potently and to a greater extent than the response to thrombin. This pattern of glucocorticoid regulation was also observed at the GM-CSF mRNA level and was reproduced with other glucocorticoids such as fluticasone propionate. IL-1alpha and thrombin stimulated NF-kappa B-dependent luciferase expression equally. Dexamethasone treatment reduced luciferase expression stimulated by both IL-1alpha and thrombin. The GM-CSF mRNA half life was markedly prolonged by IL-1alpha compared to thrombin. This IL-1alpha-induced GM-CSF mRNA stability was prevented by either dexamethasone or the p38(MAPK) inhibitor, SB203580, neither of which influenced GM-CSF mRNA stability in thrombin-treated cells. Dexamethasone inhibited p38(MAPK) phosphorylation in IL-1alpha-stimulated ASM, whereas thrombin does not stimulate p38(MAPK) phosphorylation. These data suggest that the mechanism underlying the greater potency and efficacy of glucocorticoids in reducing GM-CSF synthesis stimulated by IL-1alpha depends on inhibition of the involvement of p38(MAPK)-induced increases in GM-CSF message stability.
 ...
PMID:Stimulus-dependent glucocorticoid-resistance of GM-CSF production in human cultured airway smooth muscle. 1573 56

Airway mesenchymal cells, such as myofibroblasts and airway smooth muscle cells, contribute to inflammation, airway remodelling and hyperresponsiveness in asthma by excessive proliferation and inflammatory mediator production. Using endobronchial biopsies obtained from both nonasthmatic and asthmatic subjects, in situ proliferation was assessed by immunostaining for cyclin D1. The number of immunoreactive cells increased with asthma severity and was restricted to the epithelium and subepithelial connective tissue. Despite increases in smooth muscle area, cyclin D1 was not detected in cells in intact muscle bundles. Biopsy-derived cell cultures were characterised as predominantly myofibroblasts, and were assessed to determine whether proliferation and cytokine production varied with asthma status. Cell enumeration showed that basal proliferation was similar in cells from nonasthmatics and asthmatics, and mitogenic responses to fibroblast growth factor-2, thrombin or serum were either reduced or unchanged in cells from asthmatics. Interleukin (IL)-1-dependent granulocyte-macrophage colony-stimulating factor and IL-8 release was increased in cell supernatants from asthmatics. Thus, increased rates of cellular proliferation identified in situ in the asthmatic airway occurred outside the expanded smooth muscle compartment. Although reduced proliferative responses were observed in cultured myofibroblasts from asthmatics, the increased cytokine production by these cells suggests that this contributes to and may perpetuate ongoing inflammation in asthma.
 ...
PMID:Proliferation is not increased in airway myofibroblasts isolated from asthmatics. 1835 54


1 2 Next >>