REN and chronic kidney disease: CKD is associated with a wide range of mechanisms, including aberrant cellular activities such as fibroblast activation, monocyte/macrophage infiltration and epithelial-to-mesenchymal transition (EMT); the activation of molecules such as renin-angiotensin system (RAS), noncoding RNAs and aryl hydrocarbon receptor (Lu et al., 2020; Zhou et al., 2021; Cao et al., 2022); and the dysregulation of pathways such as Wnt/β-catenin and transforming growth factor-β (TGF-β)/Smad signals (Wang et al., 2018a; Yu et al., 2022).