Fig. 3
From: Focusing on the hypoxia-inducible factor pathway: role, regulation, and therapy for osteoarthritis
HIF-1α and HIF-2α have different functions in OA. HIF-1α mainly maintains the extracellular matrix synthesis of chondrocytes and chondrocyte differentiation and promotes the balance of articular cartilage autophagy in the body. NF-κB activation promotes the heterodimerization of HIF-2α and RNTL, leading to the activation of the transcription factor HIF-2α, and through the IHH and RUNX2 axes, coactivating MMP13 prompts articular chondrocytes to show a hypertrophic state of differentiation, leading to the occurrence and progression of OA