title: Syndecan-3 is selectively pro-inflammatory in the joint and contributes to antigen-induced arthritis in mice.
abstract: BACKGROUND
  Syndecans are heparan sulphate proteoglycans expressed by endothelial cells. Syndecan-3 is expressed by synovial endothelial cells of rheumatoid arthritis (RA) patients where it binds chemokines, suggesting a role in leukocyte trafficking. The objective of the current study was to examine the function of syndecan-3 in joint inflammation by genetic deletion in mice and compare with other tissues.
  
  
  METHODS
  Chemokine C-X-C ligand 1 (CXCL1) was injected in the joints of syndecan-3-/-and wild-type mice and antigen-induced arthritis performed. For comparison chemokine was administered in the skin and cremaster muscle. Intravital microscopy was performed in the cremaster muscle.
  
  
  RESULTS
  Administration of CXCL1 in knee joints of syndecan-3-/-mice resulted in reduced neutrophil accumulation compared to wild type. This was associated with diminished presence of CXCL1 at the luminal surface of synovial endothelial cells where this chemokine clustered and bound to heparan sulphate. Furthermore, in the arthritis model syndecan-3 deletion led to reduced joint swelling, leukocyte accumulation, cartilage degradation and overall disease severity. Conversely, CXCL1 administration in the skin of syndecan-3 null mice provoked increased neutrophil recruitment and was associated with elevated luminal expression of E-selectin by dermal endothelial cells. Similarly in the cremaster, intravital microscopy showed increased numbers of leukocytes adhering and rolling in venules in syndecan-3-/-mice in response to CXCL1 or tumour necrosis factor alpha.
  
  
  CONCLUSIONS
  This study shows a novel role for syndecan-3 in inflammation. In the joint it is selectively pro-inflammatory, functioning in endothelial chemokine presentation and leukocyte recruitment and cartilage damage in an RA model. Conversely, in skin and cremaster it is anti-inflammatory.
authors.forename: Oksana
authors.initials: O
authors.lastname: Kehoe
authors.forename: Neena
authors.initials: N
authors.lastname: Kalia
authors.forename: Sophie
authors.initials: S
authors.lastname: King
authors.forename: Andrew
authors.initials: A
authors.lastname: Eustace
authors.forename: Charlotte
authors.initials: C
authors.lastname: Boyes
authors.forename: Ofer
authors.initials: O
authors.lastname: Reizes
authors.forename: Anwen
authors.initials: A
authors.lastname: Williams
authors.forename: Angela
authors.initials: A
authors.lastname: Patterson
authors.forename: Jim
authors.initials: J
authors.lastname: Middleton
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000276:immunology* / Q000473:pathology; D001172:Arthritis, Rheumatoid / Q000276:immunology* / Q000473:pathology; D054360:Chemokine CXCL1 / Q000276:immunology / Q000633:toxicity; D005455:Fluorescent Antibody Technique; D007249:Inflammation; D007719:Knee Joint / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D020556:Neutrophil Infiltration / Q000276:immunology; D053670:Syndecan-3 / Q000276:immunology*
chemical_list: D054360:Chemokine CXCL1; C475895:Cxcl1 protein, mouse; C508302:Sdc3 protein, mouse; D053670:Syndecan-3