title: Vimentin fragments are potential markers of rheumatoid synovial fibroblasts.
abstract: OBJECTIVE
  To study the protein expression differences between primary fibroblasts explanted from synovial membranes of patients with rheumatoid arthritis (RA) and osteoarthritis (OA).
  
  
  METHODS
  Fibroblast cultures were obtained from 10 patients with RA and 5 patients with OA. After two-dimensional gel electrophoresis, proteins were excised and identified using peptide mass fingerprint. Expression of selected proteins was subsequently examined by immunoblot. Furthermore, we examined the cellular lysates for the presence of citrullinated proteins.
  
  
  RESULTS
  The study was designed to compare expression changes of the common proteins detected in all studied fibroblast cultures (i.e. detected in all patients samples). We totally identified 191 shared proteins between RA and OA fibroblasts. A significant difference was defined as at least 2-fold upregulation or 0.6-fold downregulation of protein expression. The most obvious alteration observed in RA was the appearance of several vimentin fragments not present in OA. We did not detect citrullinated proteins in lysates from RA fibroblasts. This corroborates the current assumption that fibroblasts are not able to citrullinate proteins by themselves and that invading macrophages play a central role in this process.
  
  
  CONCLUSIONS
  We demonstrated that fibroblasts from patients with RA, despite being grown under identical conditions, preserve a particular feature and generate vimentin fragments not present in fibroblasts from OA. Elevated levels of different vimentin fragments have been recently reported in several rheumatic conditions. Further studies are needed to elucidate the pathogenic mechanisms induced by vimentin fragments in RA.
authors.affiliation: Department of Nephrology and Rheumatology, University Medical Center, Göttingen, Germany.
authors.forename: Radovan
authors.initials: R
authors.lastname: Vasko
authors.affiliation: Department of Nephrology and Rheumatology, University Medical Center, Göttingen, Germany.
authors.forename: Jan-Hendrik
authors.initials: JH
authors.lastname: Streich
authors.affiliation: Department of Nephrology and Rheumatology, University Medical Center, Göttingen, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Blaschke
authors.affiliation: Department of Nephrology and Rheumatology, University Medical Center, Göttingen, Germany.
authors.forename: Gerhard A
authors.initials: GA
authors.lastname: Müller
authors.affiliation: Vitos Orthopaedic Clinic, Kassel, Germany.
authors.forename: Burkhard
authors.initials: B
authors.lastname: Mai
authors.affiliation: Bruker Daltonik GmbH, Bremen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Kostrzewa
authors.affiliation: Bruker Daltonik GmbH, Bremen, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Sparbier
authors.affiliation: Department of Nephrology and Rheumatology, University Medical Center, Göttingen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Korsten
authors.affiliation: Center for Engineering in Medicine, Harvard Medical School, Boston, MA, USA.
authors.forename: Stefan
authors.initials: S
authors.lastname: Bohr
authors.affiliation: Department of Nephrology and Rheumatology, University Medical Center, Göttingen, Germany. dihazi@med.uni-goettingen.de.
authors.forename: Hassan
authors.initials: H
authors.lastname: Dihazi
mesh_terms: D001172:Arthritis, Rheumatoid / Q000378:metabolism / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D006801:Humans; D010003:Osteoarthritis / Q000378:metabolism / Q000473:pathology; D013583:Synovial Membrane / Q000378:metabolism / Q000473:pathology; D014746:Vimentin / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D014746:Vimentin