title: The metastasis-associated protein S100A4 promotes the inflammatory response of mononuclear cells via the TLR4 signalling pathway in rheumatoid arthritis.
abstract: OBJECTIVE
  S100A4 has been implicated in cancer and several inflammatory diseases, including RA. The aim of the present study was to determine whether S100A4 can stimulate proinflammatory cytokine production in mononuclear cells.
  
  
  METHODS
  Peripheral blood mononuclear cells (PBMCs) isolated from patients with RA were stimulated with S100A4, S100A8, S100A9 and S100A12. The production of IL-1β, IL-6 and TNF-α was measured by ELISA. Receptor for advanced glycation end products (RAGEs) and Toll-like receptor 4 (TLR4) signalling were examined. For signalling pathway blocking studies, inhibitors of myeloid differentiation primary response gene 88 (MyD88), nuclear factor kappa B (NF-κB) and the mitogen activated protein (MAP) kinases p38, extracellular signal-regulated kinase 1/2 (ERK1/2) and Jun N-terminal kinase (JNK) were used. MAP kinase activation was evaluated by western blotting.
  
  
  RESULTS
  Stimulation of PBMCs with S100A4 significantly up-regulated IL-1β, IL-6 and TNF-α production compared with unstimulated cells (P < 0.001). Importantly, the production of these cytokines was markedly enhanced in response to S100A4 compared with S100A8 and S100A12; however, it was less pronounced compared with S100A9. Furthermore, enhanced production of proinflammatory cytokines in S100A4-stimulated PMBCs was at least partly mediated via TLR4, but not RAGEs, and by activation of the transcription factor NF-κB and the MAP kinases p38 and ERK1/2.
  
  
  CONCLUSIONS
  This is the first study to demonstrate that S100A4 can induce an inflammatory response mediated by TLR4 and by the activation of NF-κB and the kinases p38 and ERK1/2 in mononuclear cells from patients with RA. Therefore S100A4 may be a potential therapeutic target for immune-mediated diseases.
authors.affiliation: Institute of Rheumatology and Department of Rheumatology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic, Center of Experimental Rheumatology, University Hospital Zurich, Zurich, Switzerland and Neuro-oncology Group, Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark.
authors.forename: Lucie Andrés
authors.initials: LA
authors.lastname: Cerezo
authors.affiliation: Institute of Rheumatology and Department of Rheumatology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic, Center of Experimental Rheumatology, University Hospital Zurich, Zurich, Switzerland and Neuro-oncology Group, Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark.
authors.forename: Martina
authors.initials: M
authors.lastname: Remáková
authors.affiliation: Institute of Rheumatology and Department of Rheumatology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic, Center of Experimental Rheumatology, University Hospital Zurich, Zurich, Switzerland and Neuro-oncology Group, Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark.
authors.forename: Michal
authors.initials: M
authors.lastname: Tomčik
authors.affiliation: Institute of Rheumatology and Department of Rheumatology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic, Center of Experimental Rheumatology, University Hospital Zurich, Zurich, Switzerland and Neuro-oncology Group, Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark.
authors.forename: Steffen
authors.initials: S
authors.lastname: Gay
authors.affiliation: Institute of Rheumatology and Department of Rheumatology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic, Center of Experimental Rheumatology, University Hospital Zurich, Zurich, Switzerland and Neuro-oncology Group, Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark.
authors.forename: Michel
authors.initials: M
authors.lastname: Neidhart
authors.affiliation: Institute of Rheumatology and Department of Rheumatology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic, Center of Experimental Rheumatology, University Hospital Zurich, Zurich, Switzerland and Neuro-oncology Group, Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark.
authors.forename: Eugene
authors.initials: E
authors.lastname: Lukanidin
authors.affiliation: Institute of Rheumatology and Department of Rheumatology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic, Center of Experimental Rheumatology, University Hospital Zurich, Zurich, Switzerland and Neuro-oncology Group, Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark.
authors.forename: Karel
authors.initials: K
authors.lastname: Pavelka
authors.affiliation: Institute of Rheumatology and Department of Rheumatology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic, Center of Experimental Rheumatology, University Hospital Zurich, Zurich, Switzerland and Neuro-oncology Group, Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark.
authors.forename: Mariam
authors.initials: M
authors.lastname: Grigorian
authors.affiliation: Institute of Rheumatology and Department of Rheumatology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic, Center of Experimental Rheumatology, University Hospital Zurich, Zurich, Switzerland and Neuro-oncology Group, Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark.
authors.forename: Jiří
authors.initials: J
authors.lastname: Vencovský
authors.affiliation: Institute of Rheumatology and Department of Rheumatology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic, Center of Experimental Rheumatology, University Hospital Zurich, Zurich, Switzerland and Neuro-oncology Group, Laboratory of Neural Plasticity, Department of Neuroscience and Pharmacology, Faculty of Health Sciences, Copenhagen University, Copenhagen, Denmark. senolt@revma.cz.
authors.forename: Ladislav
authors.initials: L
authors.lastname: Šenolt
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D005260:Female; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D016328:NF-kappa B / Q000378:metabolism; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D015854:Up-Regulation / Q000502:physiology
chemical_list: D016207:Cytokines; D016328:NF-kappa B; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; C077591:S100A4 protein, human
keywords: RAGE; S100A4; Toll-like receptor 4; pro-inflammatory cytokines; rheumatoid arthritis