title: High molecular weight hyaluronic acid down-regulates the gene expression of osteoarthritis-associated cytokines and enzymes in fibroblast-like synoviocytes from patients with early osteoarthritis.
abstract: OBJECTIVE
  Activated synoviocytes play important roles in the progression of human osteoarthritis (OA). Intra-articular injection of high molecular weight hyaluronic acid (HMW-HA) has been used as viscosupplementation for knee OA but its effect on synoviocytes remains undisclosed. This study aims to investigate the effects of HMW-HA on the gene expression of 16 OA-associated cytokines and enzymes, including interleukin (IL)-1beta, IL-6, IL-8, leukemia inhibitory factor (LIF), tumor necrosis factor (TNF)-alpha, TNF-alpha converting enzyme (TACE), matrix metalloproteinase (MMP)-1, MMP-2, MMP-3, MMP-9, MMP-13, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, aggrecanase-1, aggrecanase-2, and inducible nitric oxide synthase (iNOS), in fibroblast-like synoviocytes (FLS) from patients with early stage OA.
  
  
  METHODS
  Synovial fluid-derived FLS were obtained from the knees of 15 patients with early stage OA. IL-1-stimulated or unstimulated FLS were cultured with or without the treatment of 600-800kDa HMW-HA. Moreover, blocking experiments with anti-CD44 monoclonal antibodies (mAb) were used to examine the involvement of CD44 in HMW-HA effects. We designed and validated the real-time quantitative polymerase chain reaction (Q-PCR) assays with SYBR Green dyes for simultaneous quantification of the expression of the 16 genes.
  
  
  RESULTS
  HMW-HA down-regulated IL-8 and iNOS gene expression in unstimulated FLS and down-regulated aggrecanase-2 and TNF-alpha gene expression in IL-1-stimulated FLS. CD44 blocking inhibited the down-regulatory effects of HMW-HA on gene expression.
  
  
  CONCLUSIONS
  HMW-HA may have a structure-modifying effect for OA by down-regulation of aggrecanase-2 in FLS. HMW-HA also has an anti-inflammatory effect by down-regulation of TNF-alpha, IL-8, and iNOS in FLS. These effects may be mediated through the interaction of CD44 and HMW-HA.
authors.affiliation: Department of Orthopedics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: C-T
authors.initials: CT
authors.lastname: Wang
authors.forename: Y-T
authors.initials: YT
authors.lastname: Lin
authors.forename: B-L
authors.initials: BL
authors.lastname: Chiang
authors.forename: Y-H
authors.initials: YH
authors.lastname: Lin
authors.forename: S-M
authors.initials: SM
authors.lastname: Hou
mesh_terms: D051722:ADAM Proteins / Q000096:biosynthesis / Q000235:genetics; D000071116:ADAMTS5 Protein; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects*; D005347:Fibroblasts / Q000276:immunology / Q000378:metabolism; D006801:Humans; D018960:Hyaluronan Receptors / Q000276:immunology; D006820:Hyaluronic Acid / Q000494:pharmacology*; D007375:Interleukin-1 / Q000276:immunology; D016209:Interleukin-8 / Q000096:biosynthesis / Q000235:genetics; D008970:Molecular Weight; D052247:Nitric Oxide Synthase Type II / Q000096:biosynthesis / Q000235:genetics; D020370:Osteoarthritis, Knee / Q000276:immunology / Q000378:metabolism*; D016133:Polymerase Chain Reaction / Q000379:methods; D013582:Synovial Fluid / Q000276:immunology / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics
chemical_list: C497483:CD44 protein, human; D016207:Cytokines; D018960:Hyaluronan Receptors; D007375:Interleukin-1; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha; D006820:Hyaluronic Acid; D052247:Nitric Oxide Synthase Type II; D051722:ADAM Proteins; D000071116:ADAMTS5 Protein; C121532:ADAMTS5 protein, human