TNF and renal fibrosis: Activation of the TLR–NF-κB pathway enhances the production of pro-inflammatory cytokines, including interleukin (IL)-6, IL-1β, IL-18, and tumor necrosis factor-α (TNF-α), and stimulates transforming growth factor-β1 (TGF-β1), a key mediator of renal fibrosis [11,12,13].