CNR2 and renal fibrosis: In vivo and in vitro, it has proved that the abnormally expressed cannabinoid receptor type 2 (CB2) is closely related to renal fibrosis via β-arrestin 1-induced β-catenin activation, and β-catenin could promote the activation and expression of CB2, and finally forms the vicious circle in the CB2/β-catenin pathway (Zhou et al., 2021).