title: Influence of epitopes CD44v3 and CD44v6 in the invasive behavior of fibroblast-like synoviocytes derived from rheumatoid arthritic joints.
abstract: OBJECTIVE
  To investigate the functional implications of CD44 splice variant expression in fibroblast-like synoviocytes (FLS) obtained from patients with rheumatoid arthritis (RA).
  
  
  METHODS
  FLS were isolated from synovial tissue obtained from both diseased and nondiseased joints. The expression of splice variants containing exons v3 and v6 was analyzed using immunocytochemistry with exon-specific antibodies and reverse transcription-polymerase chain reaction followed by Southern blotting. The invasive capacity of the cells was studied in a transwell invasion assay.
  
  
  RESULTS
  FLS obtained from RA joints expressed various CD44 splicing combinations containing the variant exons v3 and/or v6. These cells were highly invasive, whereas cells from normal tissues, which lacked expression of CD44 splice variants, were not. Variant exons CD44v3 and CD44v6 were instrumental in matrix invasion in vitro, with cells enriched for CD44v3 and v6 exhibiting greater invasion and antibodies that specifically recognize CD44v3 and v6 abrogating this capacity to invade. Invasive cells showed a reduced expression of CD44v7/8, and antibodies against this epitope had no significant effect on cellular infiltration of the matrix. The antibodies had no effect on cell migration into the porous section of the transwell.
  
  
  CONCLUSIONS
  FLS obtained from patients with RA express CD44 splice variants and are highly invasive, whereas cells obtained from healthy tissue do not express these variants and are not invasive. Expression of the epitopes CD44v3 and CD44v6 is instrumental in the invasive capacity but not in cell migration. This finding highlights a functional implication for the expression of CD44 splice variants at the level of matrix degradation.
authors.affiliation: University College London, London, UK.
authors.forename: Auragun
authors.initials: A
authors.lastname: Wibulswas
authors.forename: Daniel
authors.initials: D
authors.lastname: Croft
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Pitsillides
authors.forename: Ian
authors.initials: I
authors.lastname: Bacarese-Hamilton
authors.forename: Peter
authors.initials: P
authors.lastname: McIntyre
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Genot
authors.forename: Ijsbrand M
authors.initials: IM
authors.lastname: Kramer
mesh_terms: D017398:Alternative Splicing; D001172:Arthritis, Rheumatoid / Q000378:metabolism* / Q000473:pathology; D015153:Blotting, Western; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D000939:Epitopes; D005091:Exons; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D006023:Glycoproteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D007596:Joints / Q000378:metabolism* / Q000473:pathology; D022821:RNA Splice Sites; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013583:Synovial Membrane / Q000378:metabolism* / Q000473:pathology
chemical_list: C121450:CD44V3,8-10; C112697:CD44v6 antigen; D000939:Epitopes; D006023:Glycoproteins; D018960:Hyaluronan Receptors; D022821:RNA Splice Sites