scholarly journals Inhibition of Cytokine Gene Expression by Sodium Salicylate in a Macrophage Cell Line through an NF-κB-Independent Mechanism

1999 ◽  
Vol 6 (4) ◽  
pp. 567-572 ◽  
Author(s):  
Serge Lemay ◽  
Tatiana V. Lebedeva ◽  
Ajay K. Singh

ABSTRACT Macrophage-derived cytokines and chemokines are involved at multiple steps of immune and inflammatory responses, and the transcriptional factor NF-κB appears to play a pivotal role in their coordinated upregulation. The anti-inflammatory agents salicylates have been proposed to act in part by inhibiting NF-κB. We have therefore studied the effects of sodium salicylate on lipopolysaccharide (LPS)-induced κB-binding activity and on cytokine and chemokine gene expression in the RAW264.7 murine macrophage cell line and compared them to those of an established NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC). PDTC (100 μM) completely abrogated LPS-induced κB-binding activity and also profoundly inhibited the induction of interleukin 1α (IL-1α), IL-1β, IL-6, IL-10, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and MCP-1 and, to a lesser extent, leukemia inhibitory factor, RANTES, and IL-1Ra. In contrast, sodium salicylate (15 to 20 mM) had no effect on NF-κB activation but, nevertheless, suppressed several LPS-induced cytokine and chemokine genes to a degree similar to that obtained with PDTC. However, compared to PDTC, sodium salicylate caused significantly less inhibition of IL-1Ra and IL-10 gene expression after LPS stimulation. Neither LPS-induced MIP-1α, MIP-1β, nor MIP-2 was significantly affected by PDTC or sodium salicylate, demonstrating that NF-κB is dispensable for the transcriptional regulation of these genes by LPS. In summary, these results suggest that both NF-κB-dependent and NF-κB-independent pathways are necessary for the induction by LPS of a complex cytokine and chemokine response. In the RAW264.7 macrophage cell line, suprapharmacological concentrations of sodium salicylate exert a potent inhibitory effect on LPS-induced cytokine gene induction but appear to accomplish this by interfering with NF-κB-independent pathways of activation.

1990 ◽  
Vol 10 (6) ◽  
pp. 2991-3002
Author(s):  
P van der Geer ◽  
T Hunter

The receptor for colony-stimulating factor 1 (CSF-1) is a ligand-activated protein-tyrosine kinase. It has been shown previously that the CSF-1 receptor is phosphorylated on serine in vivo and that phosphorylation on tyrosine can be induced by stimulation with CSF-1. We studied the phosphorylation of the CSF-1 receptor by using the BAC1.2F5 murine macrophage cell line, which naturally expresses CSF-1 receptors. Two-dimensional tryptic phosphopeptide mapping showed that the CSF-1 receptor is phosphorylated on several different serine residues in vivo. Stimulation with CSF-1 at 37 degrees C resulted in rapid phosphorylation on tyrosine at one major site and one or two minor sites. We identified the major site as Tyr-706. The identity of Tyr-706 was confirmed by mutagenesis. This residue is located within the kinase insert domain. There was no evidence that Tyr-973 (equivalent to Tyr-969 in the human CSF-1 receptor) was phosphorylated following CSF-1 stimulation. When cells were stimulated with CSF-1 at 4 degrees C, additional phosphotyrosine-containing phosphopeptides were detected and the level of phosphorylation of the individual phosphotyrosine-containing phosphopeptides was substantially increased. In addition, we show that CSF-1 receptors are capable of autophosphorylation at six to eight major sites in vitro.


2000 ◽  
Vol 347 (1) ◽  
pp. 313-320 ◽  
Author(s):  
Lindsay F. FOWLES ◽  
Katryn J. STACEY ◽  
Denese MARKS ◽  
John A. HAMILTON ◽  
David A. HUME

Macrophage colony-stimulating factor (CSF-1) binds to a receptor (CSF-1R) encoded by the c-fms proto-oncogene and activates transcription of the urokinase plasminogen activator (uPA) gene in murine bone-marrow-derived macrophages. This article demonstrates that the murine macrophage cell line RAW264 responds to CSF-1 with inducible phosphorylation of cytoplasmic proteins on tyrosine residues but fails to induce transcription of uPA. The defect was correlated with a selective failure to maintain CSF-1Rs on the cell surface, whereas all RAW264 cells contained abundant CSF-1Rs within the presumptive Golgi/endoplasmic reticulum compartment. Transfection with a CSF-1R expression plasmid permitted CSF-1-dependent activation of the signalling pathway targeting an Ets/AP1 (activator protein 1) element in the uPA promoter that has been shown previously to be a target of oncogenic ras and protein kinase C pathways. Mutation of the expressed CSF-1R at either Y807 or Y559, sites of receptor tyrosine phosphorylation implicated in signal transduction, reduced but did not abolish uPA promoter activation by CSF-1. Activation by mutant CSF-1R plasmids was additive; there was no evidence of mutual complementation. The results indicate that maintenance of elevated uPA transcription by CSF-1 requires new receptors emerging continuously on the cell surface. Parallel, partly redundant, signalling pathways arising from phosphorylated tyrosines on the CSF-1R activate multiple cis-acting elements on the complex uPA promoter.


1989 ◽  
Vol 93 (3) ◽  
pp. 447-456 ◽  
Author(s):  
C.A. Boocock ◽  
G.E. Jones ◽  
E.R. Stanley ◽  
J.W. Pollard

The cloned, SV40-immortalized mouse macrophage cell line, BAC1.2F5, resembles primary macrophages in its dependence on colony-stimulating factor-1 (CSF-1) for both viability and proliferation. Re-addition of CSF-1 stimulates rapid, transient behavioural changes in starved cells, which are rounded, with diffusely organized F-actin and few intracellular vesicles. Within 1 min, cells begin to spread, forming prominent, F-actin-rich ruffles. Small vesicles (0.5-1.0 microns), formed throughout extending lamellar processes, move centripetally and, after 3–5 min, fuse to form larger vesicles (2.0-4.0 microns), clustered around the nucleus. Immunofluorescence demonstrates that CSF-1, bound to cell-surface receptors, is internalized via these vesicles. Cell spreading and ruffling peak about 5 min after restimulation. Interference reflection microscopy indicates no corresponding change in the mode of cell-substratum adhesion: a single area of close adhesion underlies most of the cell and simply broadens during spreading. Analysis of cell aggregation kinetics shows no effect of CSF-1 on intercellular adhesiveness. Measurement of cell areas after starvation and restimulation demonstrates quantitatively the time-course and concentration-dependence of cell spreading. Mean area doubles within 5 min and, after a transient peak, decreases within 30 min to the value measured before starvation. This time-course corresponds to that of CSF-1 internalization and of the phosphorylation and subsequent degradation of CSF-1 receptors. The concentration-dependence of the spreading response resembles that of CSF-1-dependent survival and proliferation. The minimum detectable stimulation of spreading occurs at the concentration (22 pM) that supports survival without proliferation. Increasing stimulation of spreading occurs over the range of concentrations that elicit increasing proliferation.


1990 ◽  
Vol 10 (6) ◽  
pp. 2991-3002 ◽  
Author(s):  
P van der Geer ◽  
T Hunter

The receptor for colony-stimulating factor 1 (CSF-1) is a ligand-activated protein-tyrosine kinase. It has been shown previously that the CSF-1 receptor is phosphorylated on serine in vivo and that phosphorylation on tyrosine can be induced by stimulation with CSF-1. We studied the phosphorylation of the CSF-1 receptor by using the BAC1.2F5 murine macrophage cell line, which naturally expresses CSF-1 receptors. Two-dimensional tryptic phosphopeptide mapping showed that the CSF-1 receptor is phosphorylated on several different serine residues in vivo. Stimulation with CSF-1 at 37 degrees C resulted in rapid phosphorylation on tyrosine at one major site and one or two minor sites. We identified the major site as Tyr-706. The identity of Tyr-706 was confirmed by mutagenesis. This residue is located within the kinase insert domain. There was no evidence that Tyr-973 (equivalent to Tyr-969 in the human CSF-1 receptor) was phosphorylated following CSF-1 stimulation. When cells were stimulated with CSF-1 at 4 degrees C, additional phosphotyrosine-containing phosphopeptides were detected and the level of phosphorylation of the individual phosphotyrosine-containing phosphopeptides was substantially increased. In addition, we show that CSF-1 receptors are capable of autophosphorylation at six to eight major sites in vitro.


Blood ◽  
1993 ◽  
Vol 82 (8) ◽  
pp. 2470-2477 ◽  
Author(s):  
JH Park ◽  
L Levitt

Abstract Transfected Jurkat cells overexpressing extracellular signal-regulated kinase (ERK1), also referred to as mitogen-activated protein (MAP) kinase, were selected by Western blotting assay using anti-ERK1 and antiphosphotyrosine antibodies in combination with a functional MAP kinase assay. We then asked whether enhanced ERK1 expression had any effect on induction of T-cell cytokine genes. The results show that overexpression of ERK1 enhances expression of T-cell interleukin-2 (IL- 2), IL-3, and granulocyte-macrophage colony-stimulating factor mRNA; no change was seen in expression of the alpha-actin gene. DNA-binding activities of the transcription factors AP1, NF-AT, and NF-kB were specifically increased twofold to fourfold in ERK1-overexpressing clones relative to nontransformed or vector-transformed cells, whereas no enhancement of CK1-CK2 protein DNA binding activity was detected after ERK1 overexpression. Additionally, increased NF-AT DNA binding activity was associated with functional enhancement of NF-AT transactivating activity in ERK1-overexpressing cells. These results provide direct evidence for the role of MAP kinase in the regulation of cytokine gene expression and indicate that such regulation is likely mediated through the enhanced DNA binding activity of specific nuclear transcription factors.


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