Figure 3: Schematic diagram showing the role of Wnt signaling in age-related changes of cartilage. Wnt could bind to Frizzled receptors and LRP5/6 coreceptors and lead to stabilization of β-catenin via inhibition of GSK-3β mediated ubiquitination and degradation. Then β-catenin translocated to the nucleus and bound to TCF/LEF-1 transcription factors, which can inhibit and promote early chondrogenesis as well as promote hypertrophy and chondrocyte dedifferentiation.