title: Fibroblasts share mesenchymal phenotypes with stem cells, but lack their differentiation and colony-forming potential.
abstract: BACKGROUND
  Although MSCs (mesenchymal stem cells) and fibroblasts have been well studied, differences between these two cell types are not fully understood. We therefore comparatively analysed antigen and gene profiles, colony-forming ability and differentiation potential of four human cell types in vitro: commercially available skin-derived fibroblasts [hSDFs (human skin-derived fibroblasts)], adipose tissue-derived stem cells [hASCs (human adipose tissue-derived stem cells)], embryonic lung fibroblasts (WI38) and dermal microvascular endothelial cells [hECs (human dermal microvascular endothelial cells)].
  
  
  RESULTS
  hSDFs, hASCs and WI38 exhibited a similar spindle-like morphology and expressed same antigen profiles: positive for MSC markers (CD44, CD73 and CD105) and fibroblastic markers [collagen I, HSP47 (heat shock protein 47), vimentin, FSP (fibroblast surface protein) and αSMA (α smooth muscle actin)], and negative for endothelial cell marker CD31 and haemopoietic lineage markers (CD14 and CD45). We further analysed 90 stem cell-associated gene expressions by performing real-time PCR and found a more similar gene expression pattern between hASCs and hSDFs than between hSDFs and WI38. The expression of embryonic stem cell markers [OCT4, KLF4, NANOG, LIN28, FGF4 (fibroblast growth factor 4) and REST] in hASCs and hSDFs was observed to differ more than 2.5-fold as compared with WI38. In addition, hSDFs and hASCs were able to form colonies and differentiate into adipocytes, osteoblasts and chondrocytes in vitro, but not WI38. Moreover, single cell-derived hSDFs and hASCs obtained by clonal expansion were able to differentiate into adipocytes and osteoblasts. However, CD31 positive hECs did not show differentiation potential.
  
  
  CONCLUSIONS
  These findings suggest that (i) so-called commercially available fibroblast preparations from skin (hSDFs) consist of a significant number of cells with differentiation potential apart from terminally differentiated fibroblasts; (ii) colony-forming capacity and differentiation potential are specific important properties that discriminate MSCs from fibroblasts (WI38), while conventional stem cell properties such as plastic adherence and the expression of CD44, CD90 and CD105 are unspecific for stem cells.
authors.affiliation: Department of Molecular Pathology, The University of Texas M. D. Anderson Cancer Center, Unit 951, 7435 Fannin Street, Houston, TX 77054, USA.
authors.forename: Eckhard
authors.initials: E
authors.lastname: Alt
authors.forename: Yasheng
authors.initials: Y
authors.lastname: Yan
authors.forename: Sebastian
authors.initials: S
authors.lastname: Gehmert
authors.forename: Yao-Hua
authors.initials: YH
authors.lastname: Song
authors.forename: Andrew
authors.initials: A
authors.lastname: Altman
authors.forename: Sanga
authors.initials: S
authors.lastname: Gehmert
authors.forename: Daynene
authors.initials: D
authors.lastname: Vykoukal
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Bai
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D000328:Adult; D002454:Cell Differentiation; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D005260:Female; D005347:Fibroblasts / Q000166:cytology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D000090062:Kruppel-Like Factor 4; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D010641:Phenotype
chemical_list: C000715467:KLF4 protein, human; D000090062:Kruppel-Like Factor 4; D008565:Membrane Proteins