Lgr5 and Col22a1 Mark Progenitor Cells in the Lineage toward Juvenile Articular Chondrocytes

Stem Cell Reports. 2019 Oct 8;13(4):713-729. doi: 10.1016/j.stemcr.2019.08.006. Epub 2019 Sep 12.


The synovial joint forms from a pool of progenitor cells in the future region of the joint, the interzone. Expression of Gdf5 and Wnt9a has been used to mark the earliest cellular processes in the formation of the interzone and the progenitor cells. However, lineage specification and progression toward the different tissues of the joint are not well understood. Here, by lineage-tracing studies we identify a population of Lgr5+ interzone cells that contribute to the formation of cruciate ligaments, synovial membrane, and articular chondrocytes of the joint. This finding is supported by single-cell transcriptome analyses. We show that Col22a1, a marker of early articular chondrocytes, is co-expressed with Lgr5+ cells prior to cavitation as an important lineage marker specifying the progression toward articular chondrocytes. Lgr5+ cells contribute to the repair of a joint defect with the re-establishment of a Col22a1-expressing superficial layer.

Keywords: Col22a1; Gdf5; Lgr5; articular chondrocytes; joint development; joint formation; joint lineage; progenitor; single-cell transcriptome; synovial joint.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers
  • Cartilage, Articular / cytology
  • Cell Lineage* / genetics
  • Chondrocytes / cytology
  • Chondrocytes / metabolism*
  • Collagen / genetics
  • Collagen / metabolism*
  • Fluorescent Antibody Technique
  • Gene Expression
  • Immunohistochemistry
  • Mice
  • Models, Biological
  • Molecular Imaging
  • Receptors, G-Protein-Coupled / genetics
  • Receptors, G-Protein-Coupled / metabolism*
  • Stem Cells / cytology
  • Stem Cells / metabolism*
  • Synovial Membrane / cytology


  • Biomarkers
  • Lgr5 protein, mouse
  • Receptors, G-Protein-Coupled
  • Collagen