The ability to augment monocyte functions such as TNF-α-producing capacities confers a high immunostimulating potential to GM-CSF. In the present investigation, the mechanism of the GM-CSF-mediated enhancement of monocyte cytokine production was analysed with regard to the involvement of intracellular signalling pathways. GM-CSF primes human monocytes dose- and time-dependently for enhanced LPS-stimulated TNF-α synthesis. Pre-incubation with 10 ng/ml GM-CSF for 6 h before LPS stimulation (10 ng/ml) caused a 3.4 ± 1.9-fold increase in TNF-α release compared to unprimed controls. This was associated with increased phosphorylation of IκBα and elevated nuclear levels of the NF-κB components p50 and p65 and NF-κB binding to DNA. LPS-induced AP-1 binding to DNA was also enhanced in GM-CSF-pre-incubated cells. GM-CSF treatment also caused a slight increase in TLR4 expression on monocytes while CD14 expression remained unchanged. GM-CSF-priming was unaffected by inhibitors of p38 MAPK (SB203580) and lipoxygenase (NDGA). In contrast, the broad-spectrum tyrosine kinase inhibitor genistein and the MEK-1 inhibitor (PD98059) abrogated GM-CSF priming of TNF-α release and activation of both NF-κB and AP-1. It is concluded that a tyrosine kinase of the GM-CSF-triggered ERK1/2 pathway augments the LPS-induced NF-κB and AP-1 activation.
Doecke WD, Randow F., Syrbe U. et al. Monocyte deactivation in septic patients: restoration by IFN-γ treatment. Nat Med1997; 3: 678—681.
2.
Williams MA, Withington S., Newland AC, Kelsey SMMonocyte anergy in septic patients is associated with a predilection to apoptosis and is reversed by GM-CSF ex vivo. J Infect Dis1998; 178: 1421—1433.
3.
Fischer HG, Frosch S., Reske K., Reske-Kunz ABGranulocyte-macrophage colony-stimulating factor activates macrophages derived from bone marrow cultures to synthesis of MHCII molecules and to augment antigen presentation function. J Immunol1988; 141: 3882—3888.
4.
Hayes MP, Zoon KCPriming of human monocytes for enhanced lipopolysaccharide responses: expression of alpha interferon, interferon regulatory factors, and tumor necrosis factor . Infect Immun1993; 61: 3222—3227.
5.
Hayes MP, Wang J., Norcross MARegulation of interleukin-12 expression in human monocytes: selective priming by interferon-gamma of lipopolysaccharide-inducible p35 and p40 genes. Blood1995; 86: 646—650.
6.
Sisson SD, Dinarello CAProduction of interleukin-1 alpha, interleukin-1 beta and tumor necrosis factor by human mononuclear cells stimulated with granulocyte-macrophage colony-stimulating factor. Blood1988; 72: 1368—1374.
McLeish KR, Knall C., Ward RA et al. Activation of mitogen-activated protein kinase cascades during priming of human neutrophils by TNF-alpha and GM-CSF. J Leukoc Biol1998; 64: 537—545.
9.
Salh B., Hoeflick K., Kwan W., Pelech S.Granulocyte-macrophage colony-stimulating factor and interleukin-3 potentiate interferon-gamma-mediated endothelin production by human monocytes: role of protein kinase C. Immunology1998; 95: 473—479.
10.
Sibelius U. , Hattar K., Hoffmann S. et al. Distinct pathways of lipopolysaccharide priming of human neutrophil respiratory burst: role of lipid mediator synthesis and sensitivity to interleukin-10. Crit Care Med2002; 30: 2306—2312.
11.
Flohé S., Boergermann J., Dominguez FE et al. Influence of granulocyte-macrophage colony-stimulating factor (GM-CSF) on whole blood endotoxin responsiveness following trauma, cardiopulmonary bypass, and severe sepsis. Shock1999; 12: 17—24.
12.
Lu J., Lucas R., Schuchmann M. et al. GM-CSF restores innate, but not adaptive, immune response in glucocorticoidimmunosuppressed human blood in vitro. J Immunol2003; 171: 938—947.
13.
Nierhaus A. , Montag B., Timmler N. et al. Reversal of immunoparalysis by recombinant human GM-CSF in patients with severe sepsis. Intensive Care Med2003; 29: 646—651.
14.
Hayes MP, Enterline JC, Gerrard TL, Zoon KCRegulation of interferon production by human monocytes: requirements for priming for lipopolysaccharide-induced production. J Leukoc Biol1991; 50: 176—181.
15.
Randow F., Doecke WD, Bundschuh DS, Hartung T., Wendel A., Volk HDIn vitro prevention and reversal of lipopolysaccharide desensitization by IFN-gamma, IL-12, and granulocyte-macrophage colony-stimulating factor. J Immunol1997; 158: 2911—2918.
16.
Kurt-Jones EA, Mandell L., Whitney C. et al. Role of Toll-like receptor 2 (TLR2) in neutrophil activation: GM-CSF enhances TLR2 expression and TLR2-mediated IL-8 response in neutrophils. Blood2002; 100: 1860—1868.
17.
Adib-Conquy B., Cavaillon JMGamma interferon and GM-CSF prevent endotoxin tolerance in human monocytes by promoting interleukin-1 receptor-associated kinase expression and its association to MyD88 and not by modulating TLR4 expression. J Biol Chem2002; 227: 27927—27934.
18.
de Groot RP , Coffer PJ, Koenderman L.Regulation of proliferation, differentiation and survival by the IL-3/IL-5/GM-CSF receptor family. Cell Signal1998; 10: 619—628.
19.
Dang PM, Fontayne A., Hakim J., El Benna J., Perianin A.Protein kinase C zeta phosphorylates a subset of selective sites of the NADPH oxidase component p47phox and participates in formyl peptide-mediated neutrophil respiratory burst. J Immunol2001; 166: 1206—1213.
20.
Nagata M., Sedgwick JB, Busse WWDifferential effects of granulocyte-macrophage colony-stimulating factor on eosinophil and neutrophil superoxide anion generation. J Immunol1995; 155: 4948—4954.
21.
Palmantier R. , Surette ME, Sanchez A., Braquet P., Borgeat P.Priming for the synthesis of 5-lipoxygenase products in human blood ex vivo by human granulocyte-macrophage colony-stimulating factor and tumor necrosis factor-alpha. Lab Invest1994; 70: 696—704.
22.
Carter AB, Knudtson KL, Monick MM, Hunninghake GWThe p38 mitogen-activated protein kinase is required for NF-kappaBdependent gene expression. The role of TATA-binding protein (TBP). J Biol Chem1999; 274: 30858—30863.
23.
Rutault K., Hazzalin CA, Mahadevan LCCombinations of ERK and p38 MAPK inhibitors ablate tumor necrosis factor-alpha (TNF-alpha) mRNA induction. Evidence for selective destabilization of TNF-alpha transcripts. J Biol Chem2001; 276: 6666—6674.
24.
Van Hilten JA , Elliott GR, Bonta ILSpecific lipoxygenase inhibition reverses macrophage cytotasis towards P815 tumor cells in vitro induced by the calcium ionophore A23187. Prostaglandins Leukot Essent Fatty Acids1988; 34: 187—192.
25.
Carter AB, Monick MM, Hunninghake GWBoth Erk and p38 kinases are necessary for cytokine gene transcription. Am J Respir Cell Mol Biol1999; 20: 751—758.
26.
Alessi DR, Cuenda A., Cohen P., Dudley DT, Saltiel ARPD 098059 is a specific inhibitor of the activation of mitogen-activated protein kinase kinase in vitro and in vivo. J Biol Chem1995; 270, 27489—27494.
27.
Van der Bruggen , Nijenhuis S., Van Raaij E., Verhoef J., Van Asbeck BSLipopolysaccharide-induced TNF-α production by human monocytes involves raf-1/MEK1-MEK2/ERK1-ERK2 pathway. Infect Immun1999; 67: 3824—3829.
28.
Karin M., Liu Z., Zandi E.AP-1 function and regulation. Curr Opin Cell Biol1997; 9: 240—246.
29.
Means TK, Pavlovich RP, Roca D., Vermeulen MW, Fenton MJActivation of TNF-α transcription utilizes distinct MAP kinase pathways in different macrophage populations. J Leukoc Biol2000; 67: 885—893.
