FIGURE 3.

Complex role of Wnts in chondrocytes, synoviocytes, and mesenchymal stem cells. Low Wnt/β-catenin activity in chondrocytes promotes chondrocyte proliferation, chondrogenic differentiation, chondrocyte hypertrophy, and increased ECM synthesis, while high Wnt/β-catenin activity leads to chondrocyte apoptosis, hypertrophy, increased inflammation, and degradation of ECM in joints. Overexpression β-catenin contributes to the fibrocyte proliferation, pannus formation, and local inflammation in synoviocytes; moreover, it could also promote the proliferation and chondrogenic differentiation of MSCs in joints.