title: Dipeptidyl peptidase-IV in synovial fluid and in synovial fluid mononuclear cells of patients with rheumatoid arthritis.
abstract: BACKGROUND
  Dipeptidyl peptidase-IV (DPP-IV) enzymatic activity controls biological halftime of multiple local mediators. Its deregulation is associated with pathogenesis of several autoimmune diseases, including rheumatoid arthritis (RA). Although DPP-IV is the canonical representative of the group, a number of other proteins have been shown to have similar enzymatic activity. This study was aimed to identify the molecular source of DPP-IV activity in synovial fluid (SF) and fluid mononuclear cells (FMNC) in patients with RA and osteoarthritis (OA). In addition, the association of DPP-IV and the concentration of stromal cell-derived factor-1alpha (SDF), DPP-IV substrate, were evaluated.
  
  
  METHODS
  DPP-IV activity was measured by the kinetic fluorimetric method. The expression of studied molecules in FMNC and their concentrations in SF were assayed using flow cytometry and ELISA respectively.
  
  
  RESULTS
  DPP-IV activity in SF, dominantly derived from the canonical DPP-IV, does not significantly differ between RA and OA. However, a significantly lower DPP-IV activity and expression in FMNC was found in RA as opposed to OA patients. Negative correlation between SDF concentration in SF and the relative amount of CD3+CD26+ cells was observed.
  
  
  CONCLUSIONS
  We report decreased presence of DPP-IV/CD26 in CD3+ FMNC in RA, which also may participate on impaired balance of SDF concentration in SF.
authors.affiliation: Laboratory of Cancer Cell Biology, Institute of Biochemistry and Experimental Oncology, First Faculty of Medicine, Charles University in Prague, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Sromova
authors.forename: Helena
authors.initials: H
authors.lastname: Mareckova
authors.forename: Liliana
authors.initials: L
authors.lastname: Sedova
authors.forename: Eva
authors.initials: E
authors.lastname: Balaziova
authors.forename: Aleksi
authors.initials: A
authors.lastname: Sedo
mesh_terms: D000818:Animals; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000201:enzymology*; D002462:Cell Membrane / Q000201:enzymology; D018819:Dipeptidyl Peptidase 4 / Q000737:chemistry / Q000378:metabolism*; D010450:Endopeptidases; D005260:Female; D018093:Gelatinases / Q000378:metabolism; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000201:enzymology*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008875:Middle Aged; D010003:Osteoarthritis / Q000201:enzymology; D012697:Serine Endopeptidases / Q000378:metabolism; D012995:Solubility; D013582:Synovial Fluid / Q000201:enzymology*; D000099167:Fibroblast Activation Protein Alpha
chemical_list: D018819:Dipeptidyl Peptidase 4; D010450:Endopeptidases; D018093:Gelatinases; D008565:Membrane Proteins; D012697:Serine Endopeptidases; D000099167:Fibroblast Activation Protein Alpha