TLR4 and renal fibrosis: Tripterygium glycoside and triptolide could alleviate renal fibrosis involving the miR-141-3p/phosphatase and tensin homolog/AKT/mTOR pathway, TGF-β1/Smad3 pathway and TLR4/NF-κB pathway (Cao et al., 2015; Ma et al., 2015b; Li et al., 2017c).