ScxLin cells directly form a subset of chondrocytes in temporomandibular joint that are sharply increased in Dmp1-null mice. Academic Article uri icon


  • It has been assumed that the secondary cartilage in the temporomandibular joint (TMJ), which is the most complex and mystery joint and expands rapidly after birth, is formed by periochondrium-derived chondrocytes. The TMJ condyle has rich attachment sites of tendon, which is thought to be solely responsible for joint movement with a distinct cell lineage. Here, we used a Scx-Cre ERT2 mouse line (the tracing line for progenitor and mature tendon cells) to track the fate of tendon cells during TMJ postnatal growth. Our data showed a progressive differentiation of Scx lineage cells started at tendon and the fibrous layer, to cells at the prechondroblasts (Sox9 -/Col I +), and then to cells at the chondrocytic layer (Sox9 +/Col I -). Importantly, the Scx+chondrocytes remained as "permanent" chondrocytes to maintain cartilage mass with no further cell trandifferentiation to bone cells. This notion was substantiated in an assessment of these cells in Dmp1 -null mice (a hypophosphatemic rickets model), where there was a significant increase in the number of Scx lineage cells in response to hypophosphatemia. In addition, we showed the origin of disc, which is derived from Scx+cells. Thus, we propose Scx lineage cells play an important role in TMJ postnatal growth by forming the disc and a new subset of Scx+chondrocytes that do not undergo osteogenesis as the Scx - chondrocytes and are sensitive to the level of phosphorous.

published proceedings

  • Bone

author list (cited authors)

  • Ma, C., Jing, Y., Li, H., Wang, K. e., Wang, Z., Xu, C., ... Feng, J.

citation count

  • 3

complete list of authors

  • Ma, Chi||Jing, Yan||Li, Hui||Wang, Ke||Wang, Zheng||Xu, Chunmei||Sun, Xiaolin||Kaji, Deepak||Han, Xianglong||Huang, Alice||Feng, Jian

publication date

  • January 2021

published in