Xiamen Key Laboratory of Stomatological Disease Diagnosis and Treatment, Stomatological Hospital of Xiamen Medical College, Xiamen, China.
The Australia-China Centre for Tissue Engineering and Regenerative Medicine (ACCTERM), Queensland University of Technology, Brisbane, Queensland, Australia.
J Periodontal Res. 2022 Aug;57(4):835-848. doi: 10.1111/jre.13022. Epub 2022 Jun 8.
Growing evidence suggests that excessive inflammation hampers the regenerative capacity of periodontal ligament cells (PDLCs) and that activation of the Wnt/β-catenin pathway is crucial in suppressing immune dysregulation.
This study aimed to establish the role of the Wnt/β-catenin in regulating the immune microenvironment and its subsequent impact on periodontal regeneration.
Lithium chloride (LiCl, Wnt activator) was administered daily into the standard periodontal defects created in 12-week-old Lewis rats. Harvested at 1-week and 2-week post-surgery, samples were then subjected to histological and immunohistochemical evaluation of macrophage distribution and phenotype (pro-inflammatory M1 and anti-inflammatory M2). A murine macrophage cell line, RAW 264.7, was stimulated with LiCl to activate Wnt/β-catenin. Following treatment with the conditioned medium derived from the LiCl-activated macrophages, the expression of bone- and cementum-related markers of the PDLCs was determined. The involvement of Wnt/β-catenin in the immunoregulation and autophagic activity was further investigated with the addition of cardamonin, a commercially available Wnt inhibitor.
A significantly increased number of macrophages were detected around the defects during early healing upon receiving the Wnt/β-catenin signaling cue. The defect sites in week 2 exhibited fewer M1 and more M2 macrophages along with an enhanced regeneration of alveolar bone and cementum in the Wnt/β-catenin activation group. LiCl-induced immunomodulatory effect was accompanied with the activation Wnt/β-catenin signaling, which was suppressed in the presence of Wnt inhibitor. Exposure to LiCl could induce autophagy in a dose-dependent manner, thus maintaining macrophages in a regulatory state. The expression level of bone- and cementum-related markers was significantly elevated in PDLCs stimulated with LiCl-activated macrophages.
The application of Wnt activator LiCl facilitates the recruitment of macrophages to defect sites and regulates their phenotypic switching in favor of periodontal regeneration. Suppression of Wnt/β-catenin pathway could attenuate the LiCl-induced immunomodulatory effect. Taken together, the Wnt/β-catenin pathway may be targeted for therapeutic interventions in periodontal diseases.
越来越多的证据表明，过度的炎症会抑制牙周韧带细胞（PDLCs）的再生能力，而 Wnt/β-连环蛋白途径的激活对于抑制免疫失调至关重要。
本研究旨在确定 Wnt/β-连环蛋白在调节免疫微环境及其对牙周再生的后续影响中的作用。
每天将氯化锂（LiCl，Wnt 激活剂）注入 12 周龄 Lewis 大鼠标准牙周缺损部位。术后 1 周和 2 周采集样本，然后进行组织学和免疫组织化学评估，观察巨噬细胞分布和表型（促炎 M1 和抗炎 M2）。用 LiCl 刺激鼠巨噬细胞系 RAW 264.7 以激活 Wnt/β-连环蛋白。用 LiCl 激活的巨噬细胞衍生的条件培养基处理后，测定 PDLCs 的骨和牙骨质相关标志物的表达。用商售的 Wnt 抑制剂卡纳明进一步研究 Wnt/β-连环蛋白在免疫调节和自噬活性中的作用。
在接受 Wnt/β-连环蛋白信号刺激后，早期愈合过程中缺陷周围检测到的巨噬细胞数量明显增加。第 2 周时，Wnt/β-连环蛋白激活组的缺陷部位 M1 减少，M2 增加，牙槽骨和牙骨质再生增强。LiCl 诱导的免疫调节作用伴随着 Wnt/β-连环蛋白信号的激活，而在存在 Wnt 抑制剂的情况下，该信号被抑制。LiCl 以剂量依赖的方式诱导自噬，从而使巨噬细胞保持在调节状态。用 LiCl 激活的巨噬细胞刺激后，PDLCs 中骨和牙骨质相关标志物的表达水平显著升高。
Wnt 激活剂 LiCl 的应用促进了巨噬细胞向缺陷部位的募集，并调节其表型转换，有利于牙周再生。Wnt/β-连环蛋白途径的抑制可能会减弱 LiCl 诱导的免疫调节作用。总之，Wnt/β-连环蛋白途径可能成为牙周病治疗干预的靶点。
