Journal of Cellular Biochemistry

Osteogenesis and expression of the bone marrow niche in endothelial cell-depleted HipOPs

Authors

  • Kristen P. McKenzie,

    1. Department of Dentistry, University of Toronto, 1 King's College Circle, Medical Sciences Building, Room 4245, Toronto, Ontario, Canada M5S 1A8
    Search for more papers by this author
  • Dana C. Mayer,

    1. Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Medical Sciences Building, Room 4245, Toronto, Ontario, Canada M5S 1A8
    Search for more papers by this author
  • Jane E. Aubin

    Corresponding author
    1. Department of Dentistry, University of Toronto, 1 King's College Circle, Medical Sciences Building, Room 4245, Toronto, Ontario, Canada M5S 1A8
    2. Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Medical Sciences Building, Room 4245, Toronto, Ontario, Canada M5S 1A8
    • Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Medical Sciences Building, Room 4245, Toronto, Ont., Canada M5S 1A8.
    Search for more papers by this author

  • The authors declared they have no conflict of interest.

Abstract

The identification and purification of murine multipotent mesenchymal stem cells (MSCs) have been difficult due to their low frequency, the presence of contaminating cell types and lack of unambiguous markers. Using a magnetic micro-beads negative selection technique to remove hematopoietic cells from mouse bone marrow stromal cells (BMSCs), our lab recently isolated a highly purified osteoprogenitor (HipOP) population that was also enriched for other mesenchymal precursors, including MSCs [Itoh and Aubin, 2009]. We now report that HipOPs are also highly enriched in vascular endothelial cells (VECs), which we hypothesized were an accessory cell type regulating osteogenesis. However, when VECs were immunodepleted from HipOPs with anti-CD31 antibodies, the resulting CD31(−) HipOP population had equal osteogenic capacity to the HipOPs in vitro and in vivo. Analysis of gene expression of Ncad, Pth1r, Ang1, Cxcl12, Jag1, Pdgfr-β, α-sma, Desmin, and Ng2 suggested that both HipOPs and CD31(−) HipOPs are hemopoietic stem cell (HSC) niche populations. However, the data support the view that osteoblast differentiation and depletion of VECs modulate the HSC niche. J. Cell. Biochem. 114: 1066–1073, 2013. © 2012 Wiley Periodicals, Inc.

Ancillary