Fig. 2
From: Estrogen-related receptors: novel potential regulators of osteoarthritis pathogenesis
When the joint is affected by pathogenic factors such as aging, menopause, obesity, hereditary factors, and mechanical stress, the expression of the ERR family becomes disordered. a ERRα promotes chondrocyte proliferation by upregulating Sox-9. ERRα is generated in response to IL-1β stimulation through the PGE2/cAMP/PKA signaling pathways and regulates MMP-13 production. The dysregulation of ERRα may affect the aging of chondrocytes. ERRα participates in osteophyte formation and synovial hyperplasia by impacting osteoclasts. b The overexpression of the ERRγ, as regulators of IL-6, VEGFA and MMPs, will inevitably result in the dysfunction of molecular substances, disrupt homeostasis, and induce osteophyte, synovitis and cartilage degradation. ERRγ also restrains chondrocyte proliferation by upregulating p27