title: Differentiation potential of CD14+ monocytes into myofibroblasts in patients with systemic sclerosis.
abstract: BACKGROUND
  Circulating monocytes are a highly plastic and functionally heterogeneic cell type with an activated phenotype in patients with systemic sclerosis (SSc). CD14(+) monocytes have the potential to differentiate into extra-cellular matrix (ECM) producing cells, possibly participating in fibrogenesis.
  
  
  OBJECTIVE
  To study the effect of GM-CSF, IL-4 and endothelin -1 (ET-1) alone or in combination on monocyte differentiation into myofibroblasts.
  
  
  METHODS
  CD14(+) cells were isolated from peripheral blood from 14 SSc patients and healthy controls by positive selection and incubated with different combinations of GM-CSF, IL-4 and ET-1 for 14 days. Type-1 collagen and α-SMA were detected by Western blot, qPCR and confocal microscopy. HLA-DR, CD11c and CD14 expression was analysed by flow cytometry. A collagen gel contraction assay was performed for functional myofibroblast assessment.
  
  
  RESULTS
  GM-CSF both induced collagen and α-SMA expression after 14 days. ET-1 further increased GM-CSF-induced collagen expression in a dose dependent manner up to 30-fold. IL-4/GM-CSF combination leads to a more DC-like phenotype of monocytes associated with reduced collagen and α-SMA expression compared to GM-CSF alone. Collagen and α-SMA expression was higher in monocytes from SSc patients and monocytes were more prone to obtain a spindle form. In contrast to controls, ET-1 and IL-4 alone were sufficient to induce α-SMA expression in monocytes from SSc patients. Despite the induction of α-SMA expression, monocyte-derived myofibroblasts only had a moderate capability of contraction in functional analyses.
  
  
  CONCLUSIONS
  SSc monocytes display increased maturation towards myofibroblasts demonstrated by their phenotype and α-SMA expression when compared to monocytes from healthy controls, however only with minor functional contraction properties.
authors.affiliation: Musculoskeletal Research Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Nadine
authors.initials: N
authors.lastname: Binai
authors.forename: Steven
authors.initials: S
authors.lastname: O'Reilly
authors.forename: Bridget
authors.initials: B
authors.lastname: Griffiths
authors.forename: Jacob M
authors.initials: JM
authors.lastname: van Laar
authors.forename: Thomas
authors.initials: T
authors.lastname: Hügle
mesh_terms: D000199:Actins / Q000378:metabolism; D000328:Adult; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002454:Cell Differentiation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism; D019332:Endothelin-1 / Q000494:pharmacology; D005260:Female; D005782:Gels; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D015847:Interleukin-4 / Q000494:pharmacology; D018950:Lipopolysaccharide Receptors / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects / Q000473:pathology*; D058628:Myofibroblasts / Q000187:drug effects / Q000473:pathology*; D010641:Phenotype; D012595:Scleroderma, Systemic / Q000378:metabolism / Q000473:pathology*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: C541116:ACTA2 protein, human; D000199:Actins; D024042:Collagen Type I; D019332:Endothelin-1; D005782:Gels; D018950:Lipopolysaccharide Receptors; D015847:Interleukin-4; D016178:Granulocyte-Macrophage Colony-Stimulating Factor