Activation of SLIT2/ROBO1/LRP6 axis aggravates cartilage degradation via β-catenin signaling in TMJOA
Guan Luo, Baoyi Chen, Wenjun Chen, Huiyi Lin, Weiqi Guo, Qingbin Zhang, Jiang Li, Lijing Wang, Janak Lal Pathak, Yuhui Yang, Weijun Zhang, Xiaoyu Zhang, Beining Zheng, Ziyi Wang, Shiting Wei, Jiaxin He, Wei-Jie Zhou, Chang Liu
Guan Luo, Baoyi Chen, Wenjun Chen, Huiyi Lin, Weiqi Guo, Qingbin Zhang, Jiang Li, Lijing Wang, Janak Lal Pathak, Yuhui Yang, Weijun Zhang, Xiaoyu Zhang, Beining Zheng, Ziyi Wang, Shiting Wei, Jiaxin He, Wei-Jie Zhou, Chang Liu
View: Text | PDF
Research Article Bone biology Inflammation

Activation of SLIT2/ROBO1/LRP6 axis aggravates cartilage degradation via β-catenin signaling in TMJOA

Abstract

Temporomandibular joint osteoarthritis (TMJOA), a prevalent subtype of temporomandibular disorders, is characterized by progressive cartilage degradation and subchondral bone destruction. Despite advancements in understanding TMJOA pathogenesis, the molecular mechanisms underlying its progression remain unclear. In this study, elevated Slit guidance ligand 2 (SLIT2) expression was observed in TMJ tissues of unilateral anterior crossbite–induced TMJOA mice and synovial fluid from patients with TMJOA, correlating with disease severity. Furthermore, SLIT2 overexpression in transgenic mice intensified TMJOA progression, whereas heterozygous deletion of roundabout guidance receptor 1/2 (ROBO1/2) alleviated cartilage and bone damage. Mechanistically, SLIT2 promoted ROBO1-LRP6 complex formation, facilitating LRP6 phosphorylation and β-catenin nuclear translocation. This cascade upregulated matrix-degrading enzymes while downregulating cartilage structural proteins, exacerbating cartilage destruction and subchondral bone loss. These findings suggest that the SLIT2/ROBO1/LRP6 axis may represent a potential therapeutic target for TMJOA and provide mechanistic insights into disease progression.

Authors

Guan Luo, Baoyi Chen, Wenjun Chen, Huiyi Lin, Weiqi Guo, Qingbin Zhang, Jiang Li, Lijing Wang, Janak Lal Pathak, Yuhui Yang, Weijun Zhang, Xiaoyu Zhang, Beining Zheng, Ziyi Wang, Shiting Wei, Jiaxin He, Wei-Jie Zhou, Chang Liu

×

Figure 6

SLIT2/ROBO1 signaling–induced cartilage degradation is regulated by LRP6-mediated β-catenin signaling.

Options: View larger image (or click on image) Download as PowerPoint
SLIT2/ROBO1 signaling–induced cartilage degradation is regulated by LRP6...
(A) GSEA was performed using gene sets related to the Wnt/β-catenin pathway from the GO and KEGG databases to assess differences between the NC and Si-SLIT2 groups. (B and C) IHC images of active β-catenin in condylar cartilage, and quantitative analysis of the percentage of active β-catenin–positive cells (n = 4). (D and E) IHC images of p-LRP6 in condylar cartilage, and quantitative analysis of the percentage of p-LRP6–positive cells (n = 4). (F and G) Western blot detection of the effect of ROBO1 knockdown for GSK-3β and active β-catenin proteins in SW1353 chondrocytes, and relative quantification of p-GSK-3β/t-GSK-3β and active β-catenin proteins. (H and I) IF staining images of β-catenin proteins after being treated with rhSLIT2 and/or Si-ROBO1, and relative quantification of fluorescence intensity of β-catenin proteins. (J and K) Western blot analysis assessing the effect of LRP6 knockdown on rhSLIT2-induced catabolism in SW1353 chondrocytes, and relative quantification of MMP3, MMP13, and SOX9 proteins. (L and M) Western blot analysis showing the impact of LRP6 knockdown on rhSLIT2-induced nuclear translocation of β-catenin in SW1353 cells, and relative quantification of β-catenin proteins in the cytoplasm and nucleus. Scale bars: 50 μm. All data are shown as mean ± SD. Statistical significance was assessed by 2-tailed Student’s t test (C, E, and G), 2-way ANOVA with Šidák’s post hoc analysis (I and K), and 1-way ANOVA with Dunnett’s multiple-comparison test (M). *P < 0.05; **P < 0.01; ***P < 0.001.