State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine,Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou, Zhejiang, China.
J Periodontal Res. 2022 Jun;57(3):461-469. doi: 10.1111/jre.12975. Epub 2022 Feb 8.
Occlusal trauma is one of the most important local contributing factors of periodontitis. It has been reported that Wnt4, a noncanonical Wnt ligand, can inhibit osteoclast formation and inflammation and promote bone formation in vivo. However, the prospects of Wnt4 application in occlusal trauma and periodontitis have not yet been described. This study aimed to investigate the function and the corresponding mechanism of Wnt4 to regulate bone metabolism in occlusal trauma and periodontitis.
Osteogenic-induced MC3T3-E1 cells were treated with or without Porphyromonas gingivalis lipopolysaccharide (Pg. LPS) under cyclic uniaxial compressive stress. After treatment with mouse recombinant protein Wnt4 (rWnt4), the expression of osteogenic markers and activation of the IKK-NF-κB signaling pathway were evaluated in vitro. To investigate whether Wnt4 can promote osteogenesis via the ROCK signaling pathway, the expression of RhoA was evaluated in vitro. Finally, we evaluated the change in bone quantity and the activation of the IKK-NF-κB and ROCK signaling in mice with occlusal trauma and periodontitis to demonstrate the therapeutic efficacy of rWnt4 injection.
Stimulation of traumatic force and Pg. LPS stimulation suppressed the expression of osteoblast markers, but their expression was rescued after rWnt4 treatment in vitro. In addition, the inhibition of the ROCK signaling pathway induced by force loading was reversed when rWnt4 was applied in vitro. Micro-CT, H&E, and TRAP staining of the mandibles showed increased bone loss in the occlusal trauma-aggravated periodontitis group, whereas it was rescued after rWnt4 injection. The expression levels of IκBα and p65 were upregulated in occlusal trauma and periodontitis-bearing mice, whereas the expression levels of Runx2 and RhoA were downregulated. After rWnt4 injection, remarkably upregulation of Runx2 and RhoA expression was observed in occlusal trauma and periodontitis- bearing mice.
Wnt4 not only inhibits IKK-NF-κB signaling but also activates ROCK signaling to inhibit osteoclast formation and promote bone regeneration in occlusal trauma and periodontitis-bearing mice.
咬合创伤是牙周炎最重要的局部致病因素之一。有报道称，非经典 Wnt 配体 Wnt4 可抑制破骨细胞形成和炎症，并促进体内骨形成。然而，Wnt4 在咬合创伤和牙周炎中的应用前景尚未被描述。本研究旨在探讨 Wnt4 调节咬合创伤和牙周炎中骨代谢的功能和相应机制。
成骨诱导的 MC3T3-E1 细胞在循环单轴压缩应力下用牙龈卟啉单胞菌脂多糖（Pg.LPS）或不用处理。用鼠重组蛋白 Wnt4（rWnt4）处理后，在体外评估成骨标志物的表达和 IKK-NF-κB 信号通路的激活。为了研究 Wnt4 是否可以通过 ROCK 信号通路促进成骨作用，在体外评估 RhoA 的表达。最后，我们评估了咬合创伤和牙周炎小鼠骨量的变化以及 IKK-NF-κB 和 ROCK 信号通路的激活，以证明 rWnt4 注射的治疗效果。
力刺激和 Pg.LPS 刺激抑制了成骨细胞标志物的表达，但在体外用 rWnt4 处理后，其表达得到恢复。此外，在体外施加 rWnt4 时，力加载诱导的 ROCK 信号通路抑制被逆转。下颌骨的 micro-CT、H&E 和 TRAP 染色显示，在咬合创伤加重牙周炎组中骨丢失增加，而在用 rWnt4 注射后得到挽救。在咬合创伤和牙周炎负荷小鼠中，IκBα 和 p65 的表达水平上调，而 Runx2 和 RhoA 的表达水平下调。在用 rWnt4 注射后，在咬合创伤和牙周炎负荷小鼠中观察到 Runx2 和 RhoA 表达的显著上调。
Wnt4 不仅抑制 IKK-NF-κB 信号通路，还激活 ROCK 信号通路，抑制破骨细胞形成，促进咬合创伤和牙周炎小鼠的骨再生。
