State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
J Dent Res. 2024 Jul;103(7):734-744. doi: 10.1177/00220345241245033. Epub 2024 May 16.
N6-methyladenosine (mA) modification, a eukaryotic messenger RNA modification catalyzed by methyltransferase-like 3 (METTL3), plays a pivotal role in stem cell fate determination. Calvarial bone development and maintenance are orchestrated by the cranial sutures. Cathepsin K (CTSK)-positive calvarial stem cells (CSCs) contribute to mice calvarial ossification. However, the role of mA modification in regulating Ctsk lineage cells during calvarial development remains elusive. Here, we showed that METTL3 was colocalized with cranial nonosteoclastic Ctsk lineage cells, which were also associated with GLI1 expression. During neonatal development, depletion of in the Ctsk lineage cells delayed suture formation and decreased mineralization. During adulthood maintenance, loss of in the Ctsk lineage cells impaired calvarial bone formation, which was featured by the increased bone porosity, enhanced bone marrow cavity, and decreased number of osteocytes with the less-developed cellular outline. The analysis of methylated RNA immunoprecipitation sequencing and RNA sequencing data indicated that loss of METTL3 reduced Hedgehog (Hh) signaling pathway. Restoration of Hh signaling pathway by crossing alleles or by local administration of SAG21 partially rescued the abnormity. Our data indicate that METTL3 modulates Ctsk lineage cells supporting calvarial bone formation by regulating the Hh signaling pathway, providing new insights for clinical treatment of skull vault osseous diseases.
N6-甲基腺苷（mA）修饰是一种由甲基转移酶样 3（METTL3）催化的真核信使 RNA 修饰，在干细胞命运决定中起着关键作用。颅骨缝协调颅骨的发育和维持。组织蛋白酶 K（CTSK）阳性的颅顶干细胞（CSC）有助于小鼠颅顶骨的骨化。然而，mA 修饰在调节颅顶发育过程中 Ctsk 谱系细胞中的作用仍不清楚。在这里，我们发现 METTL3 与颅非成骨 Ctsk 谱系细胞共定位，这些细胞也与 GLI1 表达相关。在新生儿发育过程中，Ctsk 谱系细胞中 的耗竭延迟了缝合线的形成并减少了矿化。在成年期维持过程中，Ctsk 谱系细胞中 的缺失会损害颅顶骨的形成，其特征是骨孔隙增加、骨髓腔增强以及骨细胞数量减少，细胞轮廓发育较差。甲基化 RNA 免疫沉淀测序和 RNA 测序数据分析表明，METTL3 的缺失降低了 Hedgehog（Hh）信号通路。通过交叉 等位基因或局部给予 SAG21 恢复 Hh 信号通路部分挽救了异常。我们的数据表明，METTL3 通过调节 Hh 信号通路来调节 Ctsk 谱系细胞，从而支持颅顶骨的形成，为治疗颅穹窿骨疾病提供了新的见解。
