title: Transcriptional profile of native CD271+ multipotential stromal cells: evidence for multiple fates, with prominent osteogenic and Wnt pathway signaling activity.
abstract: OBJECTIVE
  Controversy surrounds the identity and functionality of rare bone marrow-derived multipotential stromal cells (BM-MSCs), including their differentiation capabilities, their relationship to pericytes and hematopoiesis-supporting stromal cells, and the relevance of their culture-expanded progeny in studies of skeletal biology and development of cell-based therapies. The aim of this study was to clarify the nature of candidate BM-MSCs by profiling transcripts that reflect different aspects of their putative functions in vivo.
  
  
  METHODS
  Rare, sorted BM-derived CD45(-/low) CD271(bright) (CD271) cells were analyzed using 96-gene expression arrays focused on transcripts relevant to mesenchymal-lineage differentiation (toward bone, cartilage, fat, or muscle), hematopoietic and stromal support, and molecules critical to skeletal homeostasis. These cells were compared to matched CD45+ CD271- hematopoietic-lineage cells, culture-expanded MSCs, and skin fibroblasts. When feasible, transcription was validated using flow cytometry.
  
  
  RESULTS
  CD271 cells had a transcriptional profile consistent with the multiple fates of in vivo MSCs, evident from the observed simultaneous expression of osteogenic, adipogenic, pericytic, and hematopoiesis-supporting genes (e.g., SP7 [osterix], FABP4 [fatty acid binding protein 4], ANGPT1 [angiopoietin 1], and CXCL12 [stromal cell-derived factor 1], respectively). Compared to culture-expanded MSCs and fibroblasts, CD271 cells exhibited greater transcriptional activity, particularly with respect to Wnt-related genes (>1,000-fold increased expression of FRZB [secreted frizzled-related protein 3] and WIF1 [Wnt inhibitory factor 1]). A number of transcripts were identified as novel markers of MSCs.
  
  
  CONCLUSIONS
  The native, BM-derived in vivo MSC population is endowed with a gene signature that is compatible with multiple functions, reflecting the topographic bone niche of these cells, and their signature is significantly different from that of culture-expanded MSCs. This indicates that studies of the biologic functions of MSCs in musculoskeletal diseases, including osteoporosis and osteoarthritis, should focus on in vivo MSCs, rather than their culture-adapted progeny.
authors.affiliation: NIHR Leeds Musculoskeletal Biomedical Research Unit and University of Leeds, Leeds, UK.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Churchman
authors.forename: Frederique
authors.initials: F
authors.lastname: Ponchel
authors.forename: Sally A
authors.initials: SA
authors.lastname: Boxall
authors.forename: Richard
authors.initials: R
authors.lastname: Cuthbert
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Kouroupis
authors.forename: Tarek
authors.initials: T
authors.lastname: Roshdy
authors.forename: Peter V
authors.initials: PV
authors.lastname: Giannoudis
authors.forename: Paul
authors.initials: P
authors.lastname: Emery
authors.forename: Dennis
authors.initials: D
authors.lastname: McGonagle
authors.forename: Elena A
authors.initials: EA
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D042683:Angiopoietin-1 / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D054377:Chemokine CXCL12 / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D050556:Fatty Acid-Binding Proteins / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008875:Middle Aged; D039902:Multipotent Stem Cells / Q000166:cytology / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D010012:Osteogenesis / Q000502:physiology*; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism*; D012867:Skin / Q000166:cytology; D000076182:Sp7 Transcription Factor; D017154:Stromal Cells / Q000166:cytology / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D059467:Transcriptome; D060449:Wnt Signaling Pathway / Q000502:physiology*; D055815:Young Adult
chemical_list: C467630:ANGPT1 protein, human; D042683:Angiopoietin-1; C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; C493410:FABP4 protein, human; D050556:Fatty Acid-Binding Proteins; C484065:NGFR protein, human; D009419:Nerve Tissue Proteins; D017475:Receptors, Nerve Growth Factor; D000076182:Sp7 Transcription Factor; C478163:SP7 protein, human; D014157:Transcription Factors; D017493:Leukocyte Common Antigens; C516769:PTPRC protein, human