Identification of the metaphyseal skeletal stem cell building trabecular bone

Sci Adv. 2024 Feb 23;10(8):eadl2238. doi: 10.1126/sciadv.adl2238. Epub 2024 Feb 23.

Abstract

Skeletal stem cells (SSCs) that are capable of self-renewal and multipotent differentiation contribute to bone development and homeostasis. Several populations of SSCs at different skeletal sites have been reported. Here, we identify a metaphyseal SSC (mpSSC) population whose transcriptional landscape is distinct from other bone mesenchymal stromal cells (BMSCs). These mpSSCs are marked by Sstr2 or Pdgfrb+Kitl-, located just underneath the growth plate, and exclusively derived from hypertrophic chondrocytes (HCs). These HC-derived mpSSCs have properties of self-renewal and multipotency in vitro and in vivo, producing most HC offspring postnatally. HC-specific deletion of Hgs, a component of the endosomal sorting complex required for transport, impairs the HC-to-mpSSC conversion and compromises trabecular bone formation. Thus, mpSSC is the major source of BMSCs and osteoblasts in bone marrow, supporting the postnatal trabecular bone formation.

MeSH terms

  • Bone and Bones
  • Cancellous Bone*
  • Cell Differentiation
  • Mesenchymal Stem Cells*
  • Osteoblasts
  • Osteogenesis / genetics
  • Stem Cells