State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
Am J Orthod Dentofacial Orthop. 2022 Oct;162(4):e159-e168. doi: 10.1016/j.ajodo.2022.05.011. Epub 2022 Sep 1.
This study aimed to investigate the role of wingless-type MMTV integration site family member 5a (Wnt5a)-receptor tyrosine kinase-like orphan receptor 2 (Ror2) signaling in root resorption.
The messenger RNA (mRNA) expression of Wnt5a, Ror2, and RANKL in periodontal ligament cells (PDLCs) under compression force (CF) with or without Ror2 small interfering RNA (siRNA) were measured by quantitative reverse transcription-polymerase chain reaction, and these proteins released into culture supernatants were measured using enzyme-linked immunosorbent assay. Then these PDLC-conditioned media under CF with or without Ror2 siRNA were used to culture osteoclast precursors to detect osteoclastogenesis effects via tartrate-resistant acid phosphatase staining. In in vivo studies, the odontoclast number and the root resorption volume under excessive CF with or without Ror2 siRNA were investigated by tartrate-resistant acid phosphatase immunohistochemical staining and microcomputed tomography. The protein levels for Wnt5a, Ror2, and receptor activator of nuclear factor-kappa B ligand (RANKL) in the periodontal ligament tissues were also detected using immunohistochemical staining. Finally, the odontoclast number, root resorption volume, and the mRNA and protein expressions were compared between immature and mature teeth.
The mRNA production and protein release level of Wnt5a, Ror2, and RANKL increased after CF, whereas they were significantly downregulated with Ror2 siRNA. The osteoclast number increased treating with culture medium from PDLC applying CF, but the increase was inhibited after adding Ror2 siRNA. In the animal model, the odontoclast number and root resorption volume significantly increased in the CF group but decreased in the CF with the Ror2 siRNA group. The protein levels of Wnt5a, Ror2, and RANKL in periodontal ligament were upregulated under excessive CF, and the pathway was inhibited with Ror2 siRNA. In the immature tooth group, the odontoclast number, root resorption volume, and the mRNA and protein expressions of Wnt5a-Ror2 signaling were reduced.
Wnt5a-Ror2 signaling in PDLCs enhanced by excessive CF could promote RANKL release and induce precursor differentiation, partly leading to increased odontoclast activity and ultimate root resorption. The less resorption of the immature tooth may be due to odontoclastogenesis inhibition by decreased expression of Wnt5a-Ror2 signaling.
本研究旨在探讨无翅型 MMV 整合位点家族成员 5a（Wnt5a）-受体酪氨酸激酶样孤儿受体 2（Ror2）信号在牙根吸收中的作用。
通过定量逆转录聚合酶链反应测量牙周膜细胞（PDLC）在压缩力（CF）下 Wnt5a、Ror2 和 RANKL 的信使 RNA（mRNA）表达，并用酶联免疫吸附试验测量这些蛋白质释放到培养上清液中的量。然后将这些 PDLC 条件培养基在 CF 下与或不与 Ror2 小干扰 RNA（siRNA）一起使用，以培养破骨细胞前体，通过抗酒石酸酸性磷酸酶染色检测破骨细胞生成的影响。在体内研究中，通过抗酒石酸酸性磷酸酶免疫组织化学染色和微计算机断层扫描研究过度 CF 下有或没有 Ror2 siRNA 的情况下破骨细胞数量和牙根吸收量。还使用免疫组织化学染色检测牙周组织中 Wnt5a、Ror2 和核因子 kappa B 配体受体激活剂（RANKL）的蛋白水平。最后，比较不成熟和成熟牙齿之间的破骨细胞数量、牙根吸收量以及 mRNA 和蛋白表达。
CF 后 Wnt5a、Ror2 和 RANKL 的 mRNA 产生和蛋白释放水平增加，而用 Ror2 siRNA 处理后则显著下调。用 CF 处理的 PDLC 培养的培养基处理后破骨细胞数量增加，但加入 Ror2 siRNA 后增加受到抑制。在动物模型中，CF 组破骨细胞数量和牙根吸收量明显增加，但 CF 加 Ror2 siRNA 组减少。牙周韧带中 Wnt5a、Ror2 和 RANKL 的蛋白水平在过度 CF 下上调，而用 Ror2 siRNA 处理后抑制了该途径。在不成熟牙组中，Wnt5a-Ror2 信号的 mRNA 和蛋白表达以及破骨细胞数量和牙根吸收量减少。
过度 CF 增强的 PDLC 中的 Wnt5a-Ror2 信号可促进 RANKL 释放并诱导前体分化，部分导致破骨细胞活性增加和最终牙根吸收。不成熟牙齿的吸收减少可能是由于 Wnt5a-Ror2 信号表达减少导致破骨细胞生成受到抑制。
