title: Hyaluronic acid fragments enhance the inflammatory and catabolic response in human intervertebral disc cells through modulation of toll-like receptor 2 signalling pathways.
abstract: BACKGROUND
  Intervertebral disc (IVD) degeneration is characterized by extracellular matrix breakdown and is considered to be a primary cause of discogenic back pain. Although increases in pro-inflammatory cytokine levels within degenerating discs are associated with discogenic back pain, the mechanisms leading to their overproduction have not yet been elucidated. As fragmentation of matrix components occurs during IVD degeneration, we assessed the potential involvement of hyaluronic acid fragments (fHAs) in the induction of inflammatory and catabolic mediators.
  
  
  METHODS
  Human IVD cells isolated from patient biopsies were stimulated with fHAs (6 to 12 disaccharides) and their effect on cytokine and matrix degrading enzyme production was assessed using quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). The involvement of specific cell surface receptors and signal transduction pathways in mediating the effects of fHAs was tested using small interfering RNA (siRNA) approaches and kinase inhibition assays.
  
  
  RESULTS
  Treatment of IVD cells with fHAs significantly increased mRNA expression levels of interleukin (IL)-1β, IL-6, IL-8, cyclooxygenase (COX)-2, matrix metalloproteinase (MMP)-1 and -13. The stimulatory effects of fHAs on IL-6 protein production were significantly impaired when added to IVD cells in combination with either Toll-like receptor (TLR)-2 siRNA or a TLR2 neutralizing antibody. Furthermore, the ability of fHAs to enhance IL-6 and MMP-3 protein production was found to be dependent on the mitogen-activated protein (MAP) kinase signaling pathway.
  
  
  CONCLUSIONS
  These findings suggest that fHAs may have the potential to mediate IVD degeneration and discogenic back pain through activation of the TLR2 signaling pathway in resident IVD cells.
authors: Lilian
authors: L
authors: Quero
authors: Marina
authors: M
authors: Klawitter
authors: Anja
authors: A
authors: Schmaus
authors: Melanie
authors: M
authors: Rothley
authors: Jonathan
authors: J
authors: Sleeman
authors: André N
authors: AN
authors: Tiaden
authors: Juergen
authors: J
authors: Klasen
authors: Norbert
authors: N
authors: Boos
authors: Michael O
authors: MO
authors: Hottiger
authors: Karin
authors: K
authors: Wuertz
authors: Peter J
authors: PJ
authors: Richards
mesh_terms: D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000378:metabolism* / Q000494:pharmacology; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D018836:Inflammation Mediators / Q000378:metabolism; D007403:Intervertebral Disc / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D055959:Intervertebral Disc Degeneration / Q000378:metabolism* / Q000473:pathology; D008297:Male; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D059467:Transcriptome
chemical_list: D018836:Inflammation Mediators; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D006820:Hyaluronic Acid
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