Chen Shuo, Lan Lin, Lei Jie, He Yang, Zhang Yi
Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China.
National Center of Stomatology, Beijing, China.
Front Cell Dev Biol. 2022 Mar 7;10:819689. doi: 10.3389/fcell.2022.819689. eCollection 2022.
The condyle plays a pivotal role in mandible development, which is regulated by various signaling molecules. The hedgehog (Hh) signaling pathway is known to modulate several processes during bone formation. However, the role of Gli1, as the read-out of Hh signaling activity, in condylar development and fracture healing has not been clarified. In this study, we discovered that a population of Gli1+ cells residing immediately below the cartilage functions as osteogenic progenitors by using mice. These Gli1+ cells contributed to nearly all osteoblasts in the subchondral bone during condyle postnatal development. Interestingly, Gli1-lineage cells could differentiate into osteoblasts and chondrocytes during fracture healing. Inhibiting Wnt/β-catenin signaling downregulated the proliferation and differentiation of Gli1+ cells . These findings suggest that Gli1+ progenitor cells participate in not only normal bone formation but also fracture healing; moreover, these cells may provide a potential target for promoting bone regeneration of the mandible.
髁突在下颌骨发育中起关键作用，其受多种信号分子调控。已知刺猬（Hh）信号通路在骨形成过程中调节多个过程。然而，作为Hh信号活性读出物的Gli1在髁突发育和骨折愈合中的作用尚未阐明。在本研究中，我们利用小鼠发现，一群位于软骨正下方的Gli1+细胞作为成骨祖细胞发挥作用。在髁突出生后发育过程中，这些Gli1+细胞几乎对软骨下骨中的所有成骨细胞都有贡献。有趣的是，Gli1谱系细胞在骨折愈合过程中可分化为成骨细胞和软骨细胞。抑制Wnt/β-连环蛋白信号通路会下调Gli1+细胞的增殖和分化。这些发现表明，Gli1+祖细胞不仅参与正常骨形成，还参与骨折愈合；此外，这些细胞可能为促进下颌骨骨再生提供潜在靶点。
