TABLE 2.

Novel roles of other 7TM receptors in OA.

GPCRs	Roles in pathogenesis of OA	Latent regulators	References
GPR17	Down-regulated the expression of MMP-3 and MMP-13, thereby inhibited the degradation of type II collagen	Pranlukast	Wang et al., 2020
GPR22	Contained an SNP associated with OA	NA	Kerkhof et al., 2010
GPR39	Down-regulated the expression of MMP-3, MMP-13 and ADAMTS to reduce the degradation of type II collagen and aggrecan and reversed the decrease of TIMP-1 and TIMP-2 expression	TC-G1008 AGEs	Shan et al., 2019
GPR40	Down-regulated the expression of MMP-3 and MMP-13 to inhibite the degradation of type II collagen and suppressed the activation of NF-κB signaling pathway	GW9508	Gu et al., 2020
GPR43	Reduced the release of pro-inflammatory mediators and adhesion molecules, inhibiting inflammatory signaling pathways	Butyrate	Pirozzi et al., 2018
GPR84	Modulated the expression of MMPs and ECM synthesis to regulate the pathogenesis of OA	6-OAU Lauric acid	Wang et al., 2021
GPR120	Down-regulated the expression of IL-6 and IL-8 and protected type II collagen and aggrecan by reversing the decrease in SOX9 expression	NA	Xu et al., 2020

NA, not available.