SMAD3 and renal fibrosis: In addition to its pro-inflammatory role in the progression of renal fibrosis, serum urate, together with pro-inflammatory cytokines and mediators, aggravates renal fibrosis via multiple signaling pathways, including PI3K/AKT/mTOR, MAPK/NF-κB-NLRP3 inflammasome, IL-6/JAK2/STAT3, TGF-β/SMAD3, and Wnt/β-catenin signaling pathways.