Functional Toll-like receptor 4 mutations modulate the response to fibrinogen

Summary

Fibrinogen has been implicated in atherosclerosis; in part by activating the lipopolysaccharide (LPS) receptor Toll-like receptor 4 (TLR4). The fibrinogen-TLR4 signalling pathway remains un-characterised. In human macrophages fibrinogen stimulated interleukin (IL)6 expression and ERK (extracellular signal-related kinase) phosphorylation. In HEK293-CD14-MD2 cells expressing TLR4, fibrinogen induced robust phosphorylation of ERK1, p38α and JNK and activated transcription factors NFκB, Elk-1 and AP-1 (activator protein-1).The net effect of this signaling pathway was a pro-inflammatory response characterised by IL6 and TNFα synthesis and increased IL8,matrix metalloproteinase (MMP)1, MMP9, and MCP-1 promoter activity. Two common TLR4 mutations, D299G and T399I, render the receptor LPS hyporesponsive. The effect of fibrinogen on polymorphic variant TLR4s was markedly different; enhancing activation of kinases, transcription factors, cytokine synthesis and promoter activity. This study indicates that fibrinogen activates TLR4, explaining how fibrinogen promotes inflammatory protein expression.

Keywords

Signal transduction - protein kinases/phosphatases - transcription factors - inflammation

• References

• 1 Libby P. Inflammation in atherosclerosis. Nature 2002; 420: 868-874.
• 2 Kalayoglu MV, Libby P, Byrne GI. Chlamydia pneumoniae as an emerging risk factor in cardiovascular disease. J Am Med Assoc 2002; 288: 2724-2731.
• 3 Medzhitov R, Preston-Hurlburt P, Janeway CA. A human homologue of the Drosophila Toll protein signals activation of adaptive immunity. Nature 1997; 388: 394-397.
• 4 Chow JC, Young DW, Golenbock DT. et al. Toll-like receptor-4 mediates lipopolysaccharide-induced signal transduction. J Biol Chem 1999; 274: 10689-10692.
• 5 Di Nisio M, Di Febbo C, Moretta V. et al. Effects of toll-like receptor-4 gene polymorphisms on soluble P-selectin and von Willebrand factor levels in hypercholesterolemic patients. Thromb Haemost 2007; 98: 642-646.
• 6 Arbour NC, Lorenz E, Schutte BC. et al. TLR4 mutations are associated with endotoxin hyporesponsiveness in humans. Nat Genet 2000; 25: 187-191.
• 7 Mockenhaupt FP, Cramer JP, Hamann L. et al. Toll-like receptor (TLR) polymorphisms in African children: Common TLR-4 variants predispose to severe malaria. Proc Natl Acad Sci USA 2006; 103: 177-182.
• 8 Kiechl S, Lorenz E, Reindl M. et al. Toll-like receptor 4 polymorphisms and atherogenesis. N Engl J Med 2002; 347: 185-192.
• 9 Danesh J, Lewington S, Thompson SG. et al. Plasma fibrinogen level and the risk of major cardiovascular diseases and nonvascular mortality: an individual participant meta-analysis. J Am Med Assoc 2005; 294: 1799-1809.
• 10 Di Minno G, Mancini M. Measuring plasma fibrinogen to predict stroke and myocardial infarction. Arteriosclerosis 1990; 10: 1-7.
• 11 Maitra A, Shanker J, Dash D. et al. Polymorphisms in the IL6 gene in Asian Indian families with premature coronary artery disease - The Indian Atherosclerosis Research Study. Thromb Haemost 2008; 99: 944-950.
• 12 Martorell L, Martínez-González J, Rodríguez C. et al. Thrombin and protease-activated receptors (PARs) in atherothrombosis. Thromb Haemost 2008; 99: 305-315.
• 13 Dellas C, Schremmer C, Hasenfuss G. et al. Lack of urokinase plasminogen activator promotes progression and instability of atherosclerotic lesions in apolipoprotein E-knockout mice. Thromb Haemost 2007; 98: 220-227.
• 14 Castellino FJ, Ganopolsky JG, Noria F. et al. Focal arterial inflammation is augmented in mice with a deficiency of the protein C gene. Thromb Haemost 2006; 96: 794-801.
• 15 Nylaende M, Kroese A, Stranden E. et al. Prothrombotic activity is associated with the anatomical as well as the functional severity of peripheral arterial occlusive disease. Thromb Haemost 2006; 95: 702-707.
• 16 Dorweiler B, Torzewski M, Dahm M. et al. A novel in vitro model for the study of plaque development in atherosclerosis. Thromb Haemost 2006; 95: 182-189.
• 17 Henriksson CE, Hellum M, Landsverk KS. et al. Flow cytometry-sorted non-viable endotoxin-treated human monocytes are strongly procoagulant. Thromb Haemost 2006; 96: 29-37.
• 18 Frangogiannis NG. Chemokines in ischemia and reperfusion. Thromb Haemost 2007; 97: 738-747.
• 19 Pieters M, Covic N, van der Westhuizen FH. et al. Glycaemic control improves fibrin network characteristics in type 2 diabetes - A purified fibrinogen model. Thromb Haemost 2008; 99: 691-700.
• 20 Orbe J, Zudaire M, Serrano R. et al. Increased thrombin generation after acute versus chronic coronary disease as assessed by the thrombin generation test. Thromb Haemost 2008; 99: 382-387.
• 21 Shenhar-Tsarfaty S, Ben Assayag E. et al. Persistent hyperfibrinogenemia in acute ischemic stroke / transient ischemic attack (TIA). Thromb Haemost 2008; 99: 169-173.
• 22 Xiao Q, Danton MJ, Witte DP. et al. Fibrinogen deficiency is compatible with the development of atherosclerosis in mice. J Clin Invest 1998; 101: 1184-1194.
• 23 Lou XJ, Boonmark NW, Horrigan FT. et al. Fibrinogen deficiency reduces vascular accumulation of apolipoprotein(a) and development of atherosclerosis in apolipoprotein(a) transgenic mice. Proc Natl Acad Sci USA 1998; 95: 12591-12595.
• 24 Kardys I, Uitterlinden AG, Hofman A. et al. Fibrinogen gene haplotypes in relation to risk of coronary events and coronary and extracoronary atherosclerosis: the Rotterdam Study. Thromb Haemost 2007; 97: 288-295.
• 25 Ben Assayag E, Bova I, Berliner S. et al. Gender differences in the expression of erythrocyte aggregation in relation to B beta-fibrinogen gene polymorphisms in apparently healthy individuals. Thromb Haemost 2006; 95: 428-433.
• 26 Carty CL, Cushman M, Jones D. et al. Associations between common fibrinogen gene polymorphisms and cardiovascular disease in older adults. The Cardiovascular Health Study. Thromb Haemost 2008; 99: 388-395.
• 27 Smiley ST, King JA, Hancock WW. Fibrinogen stimulates macrophage chemokine secretion through Toll-like receptor 4. J Immunol 2001; 167: 2887-2894.
• 28 Kuhns DB, Nelson EL, Alvord WG. et al. Fibrinogen induces IL-8 synthesis in human neutrophils stimulated with formyl-methionyl-leucyl-phenylalanine or leukotriene B4. J Immunol 2001; 167: 2869-2878.
• 29 Poitevin S, Cochery-Nouvellon E, Dupont A. et al. Monocyte IL-10 produced in response to lipopolysaccharide modulates thrombin generation by inhibiting tissue factor expression and release of active tissue factor-bound microparticles. Thromb Haemost 2007; 97: 598-607.
• 30 Kwak SH, Wang XQ, He Q. et al. Plasminogen activator inhibitor-1 potentiates LPS-induced neutrophil activation through a JNK-mediated pathway. Thromb Haemost 2006; 95: 829-835.
• 31 Rivera J, Vannakambadi G, Höök M. et al. Fibrinogen-binding proteins of Gram-positive bacteria. Thromb Haemost 2007; 98: 503-511.
• 32 Jensen T, Kierulf P, Sandset PM. et al. Fibrinogen and fibrin induce synthesis of proinflammatory cytokines from isolated peripheral blood mononuclear cells. Thromb Haemost 2007; 97: 822-829.
• 33 Hochart H, Jenkins PV, Preston RJ. et al. Concentration-dependent roles for heparin in modifying liopolysaccharide-induced activation of mononuclear cells in whole blood. Thromb Haemost 2008; 99: 570-575.
• 34 Matsuguchi T, Masuda A, Sugimoto K. et al. JNK-interacting protein 3 associates with Toll-like receptor 4 and is involved in LPS-mediated JNK activation. EMBO J 2003; 22: 4455-4464.
• 35 Divanovic S, Trompette A, Atabani SF. Negative regulation of Toll-like receptor 4 signaling by the Toll-like receptor homolog RP105. Nat Immunol 2005; 06: 571-578.
• 36 Wu W, Mosteller RD, Broek D. Sphingosine kinase protects lipopolysaccharide-activated macrophages from apoptosis. Mol Cell Biol 2004; 24: 7359-7369.
• 37 Rallabhandi P, Bell J, Boukhvalova MS. et al. Analysis of TLR4 polymorphic variants: new insights into TLR4/MD-2/CD14stoichiometry, structure, and signalling. J Immunol 2006; 177: 322-332.
• 38 Hodgkinson CP, Mander A, Sale GJ. Protein kinase-zeta interacts with munc18c: role in GLUT4 trafficking. Diabetologia 2005; 48: 1627-1636.
• 39 Pearce E, Tregouet DA, Samnegård A. et al. Haplotype effect of the matrix metalloproteinase-1 gene on risk of myocardial infarction. Circ Res 2005; 97: 1070-1076.
• 40 Yan C, Boyd DD. Regulation of matrix metalloproteinase gene expression. J Cell Physiol 2007; 211: 19-26.
• 41 Hoffmann E, Dittrich-Breiholz O, Holtmann H. et al. Multiple control of interleukin-8 gene expression. J Leukoc Biol 2002; 72: 847-855.
• 42 Akira S, Takeda K. Toll-like receptor signalling. Nat Rev Immunol 2004; 04: 499-511.