MAPK8 and renal fibrosis: Mechanistically, C/EBPζ upregulation promotes renal fibrosis through apoptosis and C/EBPζ expression induced in renal tissues by UUO can activate the HMGB1/TLR4/NF-κB signaling pathway to stimulate IL-1β production, which enhances TGF-β1 production via the ERK/JNK pathway and accelerates renal fibrosis by TGF-β1/SMAD2/3 signaling [282].