Fig. 3
From: Osteoarthritis: pathogenic signaling pathways and therapeutic targets
Activated Wnt canonical and non-canonical signaling pathways in OA. In healthy articular cartilage, the Wnt signaling pathway in articular cartilage and synovium is profoundly inhibited by the absence of Wnt-Wnt receptor interactions and β-catenin degradation through the proteasome pathway. In OA chondrocytes and synovial membrane cells, Wnt ligands bind to Frizzled/LRP5/6 receptors to activate the canonical pathway, in which the destruction complex moves to the cell membrane and releases β-catenin to translocate to the nucleus and binding with TCF/LEF family to control target gene transcription. For the non-canonical Wnt pathway, the protein kinase C (PKC) and c-Jun N-terminal Kinase (JNK) are activated to upregulate downstream target genes and pathways, including the calcium pathway
