Fig. 2.

Regulation of articular cartilage by NF-κB signalling. Excessive activation of NF-κB signalling upregulates HIF-2α transcription, which results in enhanced OA progression through further induction of catabolic factors such as MMPs, VEGF, and IHH. In contrast, RelA knockout in chondrocytes causes deficiency of anti-apoptotic factors such as Traf2, c-IAP1, and c-IAP2, and leads to cartilage degeneration. Moderate activity of NF-κB signalling is necessary to maintain healthy articular cartilage. HIF hypoxia-inducible factor, IHH indian hedgehog, Mmp matrix metalloproteinase, Rela v-rel reticuloendotheliosis viral oncogene homologue A, VEGF vascular endothelial growth factor