Orthodontic tooth movement (OTM) is a highly coordinated biomechanical response to orthodontic forces with active remodelling of alveolar bone but minor root resorption. Such antiresorptive properties of root relate to cementocyte mineralization, the mechanisms of which remain largely unknown. This study used the microarray analysis to explore long non-coding ribonucleic acids involved in stress-induced cementocyte mineralization. Gain- and loss-of-function experiments, including Alkaline phosphatase (ALP) activity and Alizarin Red S staining, quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, and immunofluorescence analyses of mineralization-associated factors, were conducted to verify long non-coding ribonucleic acids taurine-upregulated gene 1 (LncTUG1) regulation in stress-induced cementocyte mineralization, via targeting the Toll-like receptor 4 (TLR4)/SphK1 axis. The luciferase reporter assays, chromatin immunoprecipitation assays, RNA pull-down, RNA immunoprecipitation, and co-localization assays were performed to elucidate the interactions between LncTUG1, PU.1, and TLR4. Our findings indicated that LncTUG1 overexpression attenuated stress-induced cementocyte mineralization, while blocking the TLR4/SphK1 axis reversed the inhibitory effect of LncTUG1 on stress-induced cementocyte mineralization. The in vivo findings also confirmed the involvement of TLR4/SphK1 signalling in cementocyte mineralization during OTM. Mechanistically, LncTUG1 bound with PU.1 subsequently enhanced TLR4 promotor activity and thus transcriptionally elevated the expression of TLR4. In conclusion, our data revealed a critical role of LncTUG1 in regulating stress-induced cementocyte mineralization via PU.1/TLR4/SphK1 signalling, which might provide further insights for developing novel therapeutic strategies that could protect roots from resorption during OTM.

中文翻译：

---

长非编码 RNA LncTUG1 通过 PU.1/TLR4/SphK1 信号传导调节有利的压缩力诱导的牙骨质细胞矿化

正畸牙齿移动（OTM）是对正畸力的高度协调的生物力学反应，主动重塑牙槽骨，但牙根吸收较小。根的这种抗吸收特性与牙骨质细胞矿化有关，其机制仍然很大程度上未知。本研究使用微阵列分析来探索参与应激诱导的牙骨质细胞矿化的长非编码核糖核酸。进行了功能获得和丧失实验，包括碱性磷酸酶 (ALP) 活性和茜素红 S 染色、定量实时聚合酶链反应 (qRT-PCR)、蛋白质印迹和矿化相关因子的免疫荧光分析通过靶向 Toll 样受体 4 (TLR4)/SphK1 轴，验证长非编码核糖核酸牛磺酸上调基因 1 (LncTUG1) 在应激诱导的牙骨质细胞矿化中的调节。进行荧光素酶报告基因测定、染色质免疫沉淀测定、RNA Pull-down、RNA 免疫沉淀和共定位测定来阐明 LncTUG1、PU.1 和 TLR4 之间的相互作用。我们的研究结果表明，LncTUG1 过表达减弱了应激诱导的牙骨质细胞矿化，而阻断 TLR4/SphK1 轴则逆转了 LncTUG1 对应激诱导的牙骨质细胞矿化的抑制作用。体内研究结果还证实了 OTM 期间 TLR4/SphK1 信号参与牙骨质细胞矿化。从机制上讲，LncTUG1 与 PU.1 结合随后增强了 TLR4 启动子活性，从而在转录上提高了 TLR4 的表达。总之，我们的数据揭示了 LncTUG1 在通过 PU.1/TLR4/SphK1 信号调节应激诱导的牙骨质细胞矿化中的关键作用，这可能为开发新的治疗策略提供进一步的见解，以保护根在 OTM 期间免受吸收。