title: Versican is upregulated in circulating monocytes in patients with systemic sclerosis and amplifies a CCL2-mediated pathogenic loop.
abstract: BACKGROUND
  Altered phenotypes of circulating monocytes of patients with systemic sclerosis (SSc) have been reported, but the role of these alterations in the pathogenesis of SSc remains unclear. This study was undertaken to identify molecules that are preferentially expressed by SSc monocytes, and to investigate the roles of these molecules in the pathogenic process of SSc.
  
  
  METHODS
  We analyzed circulating CD14⁺ monocytes isolated from 36 patients with SSc and 32 healthy control subjects. The monocytes' gene expression profiles were assessed by Oligo GEArray (SABiosciences, Frederic, MA, USA) and semiquantitative or quantitative PCR; their protein expression was evaluated in culture supernatants of unstimulated monocytes by immunoblotting or ELISA, and by immunocytostaining. Monocyte chemoattractant activity of CCL2 was assessed in a TransWell system (Corning Incorporated, Corning, NY, USA) in the presence or absence of chondroitin sulfate (CS).
  
  
  RESULTS
  A step-wise approach to profiling gene expression identified that versican and CCL2 were upregulated in SSc monocytes. Subsequent analysis of proteins expressed in monocyte culture supernatants confirmed enhanced production of versican and CCL2 in SSc monocytes compared with control monocytes. CCL2 bound to CS chains of versican and colocalized with versican in the monocytes' Golgi apparatus. Finally, CCL2 had a greater ability to mediate monocyte migration when bound to CS chains, because this binding provided efficient formation of CCL2 gradients and protection from protease attack.
  
  
  CONCLUSIONS
  Circulating monocytes with elevated versican and CCL2 levels may contribute to the fibrotic process in a subset of SSc patients by amplifying a positive feedback loop consisting of versican, CCL2, and the influx of monocytes.
authors.forename: Ayako
authors.initials: A
authors.lastname: Masuda
authors.forename: Hidekata
authors.initials: H
authors.lastname: Yasuoka
authors.forename: Takashi
authors.initials: T
authors.lastname: Satoh
authors.forename: Yuka
authors.initials: Y
authors.lastname: Okazaki
authors.forename: Yukie
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Masataka
authors.initials: M
authors.lastname: Kuwana
mesh_terms: D015153:Blotting, Western; D002465:Cell Movement / Q000502:physiology; D002469:Cell Separation; D018932:Chemokine CCL2 / Q000096:biosynthesis*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012595:Scleroderma, Systemic / Q000378:metabolism* / Q000473:pathology*; D015398:Signal Transduction / Q000502:physiology; D059467:Transcriptome; D015854:Up-Regulation; D053675:Versicans / Q000096:biosynthesis*
chemical_list: C111835:CCL2 protein, human; D018932:Chemokine CCL2; D018950:Lipopolysaccharide Receptors; C508322:VCAN protein, human; D053675:Versicans