title: Cells from the skin of patients with systemic sclerosis secrete chitinase 3-like protein 1.
abstract: BACKGROUND
  The chitinase-like protein, Chi3L1, is associated with increased fibrotic activity as well as inflammatory processes. The capacity of skin cells from systemic sclerosis (SSc) patients to produce Chi3L1, and the stimulation of its synthesis by cytokines or growth factors known to be associated with SSc, was investigated.
  
  
  METHODS
  Cells were isolated from forearm and/or abdomen skin biopsies taken from SSc patients and normal individuals and stimulated with cytokines and growth factors to assess Chi3L1 expression. Chi3L1-expressing cells were characterized by immunohistochemical staining.
  
  
  RESULTS
  Chi3L1 was not secreted by skin cells from normal individuals nor was its synthesis induced by any of the cytokines or growth factors investigated. In contrast, Chi3L1 secretion was induced by OSM or IL-1 in cells from all forearm biopsies of SSc patients, and endogenous secretion in the absence of cytokines was detected in several specimens. Patients with Chi3L1-producing cells at both the arm and abdomen had a disease duration of less than 3 years. Endogenous Chi3L1 production was not a property of the major fibroblast population nor of myofibroblasts, but rather was related to the presence of stem-like cells not present in normal skin. Other cells, however, contributed to the upregulation of Chi3L1 by OSM.
  
  
  CONCLUSIONS
  The emergence of cells primed to respond to OSM with increased Chi3L1 production appears to be associated with pathological processes active in SSc.
  
  
  CONCLUSIONS
  The presence of progenitor cells expressing the chilectin Chi3L1 in SSc skin appears to play a role in the initiation of the disease process.
authors.affiliation: Shriners Hospital for Children, Department of Surgery, McGill University, 1529 Cedar Avenue, Montréal, Quebec H3G 1A6, Canada.
authors.forename: Yuen Yee
authors.initials: YY
authors.lastname: Ho
authors.affiliation: Department of Rheumatology, Jewish General Hospital, 3755 Cote Ste Catherine Road, Montréal, Quebec H3T 1E2, Canada.
authors.forename: Murray
authors.initials: M
authors.lastname: Baron
authors.affiliation: Shriners Hospital for Children, Department of Surgery, McGill University, 1529 Cedar Avenue, Montréal, Quebec H3G 1A6, Canada.
authors.forename: Anneliese D
authors.initials: AD
authors.lastname: Recklies
authors.affiliation: Shriners Hospital for Children, Department of Surgery, McGill University, 1529 Cedar Avenue, Montréal, Quebec H3G 1A6, Canada.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Roughley
authors.affiliation: Shriners Hospital for Children, Department of Surgery, McGill University, 1529 Cedar Avenue, Montréal, Quebec H3G 1A6, Canada.
authors.forename: John S
authors.initials: JS
authors.lastname: Mort
keywords: Chi3L1, chitinase 3-like protein 1; Chitinase 3-like protein 1; Cytokine; DAPI, 4′,6-diamidino-2-phenylindole; ECM, extracellular matrix; IL, interleukin; OSM, oncostatin M; Oncostatin M; PDGF, platelet-derived growth factor; SBTI, soybean trypsin inhibitor; SSc, systemic sclerosis (scleroderma); Scleroderma; Stem cell; Systemic sclerosis; TGFβ, transforming growth factor-β; TIE2, tyrosine kinase with Ig and EGF homology domains-2; mRSS, modified Rodnan skin score; αSMA, α-smooth muscle actin