Recent advances in liver preconditioning: Thyroid hormone, n-3 long-chain polyunsaturated fatty acids and iron

Figure 1 Redox signaling in T₃ liver preconditioning is mediated by activation of transcription factors nuclear factor-κB, activating protein 1, signal transducer and activator of transcription 3, and nuclear factor erythroid 2-related factor 2 triggering antioxidant, anti-apoptotic, acute-phase and proliferative responses. AP-1: Activating protein 1; APP: Acute-phase protein; CYP2E1: Cytochrome P450 isoform 2E1; GCLC: Glutamate cysteine ligase catalytic subunit; GST: Glutathione-S-transferase; HO-1: Heme-oxygenase 1; IKK: Inhibitor of IκB kinase; iNOS: Inducible nitric oxide synthase; IL-6: Interleukin-6; IL-6R: Interleukin-6 receptor; JAK: Janus kinase; JNK: c-Jun N-terminal kinase; MnSOD: Manganese superoxide dismutase; MRP: Multidrug resistance protein; NF-κB: Nuclear factor-κB; NQO-1: NAD(P)H quinone oxidoreductase 1; Nrf2: Nuclear factor-erythroid 2 related factor 2; QO₂: Rate of oxygen consumption; ROS: Reactive oxygen species; STAT3: Signal transducer and activator of transcription 3; Thr: Thioredoxin; TNF-α: Tumor necrosis factor-α; TNFR1: Tumor necrosis factor-α receptor 1; UDPGT: UDP-glucuronyl transferase.

Figure 2 n-3 long-chain polyunsaturated fatty acid -induced liver preconditioning is associated with antioxidant and anti-inflammatory responses triggered by oxidative products and peroxisome proliferator-activated receptor -α activation. n-3 LCPUFA: n-3 long-chain polyunsaturated fatty acid; COX-2: Cyclo-oxygenase 2; Keap1: Kelch-like ECH-associated protein 1; 5-LOX: 5-lipoxygenase; NF-κB: Nuclear factor-κB; Nrf2: Nuclear factor-erythroid 2 related factor 2; PPAR-α: Peroxisome proliferator-activated receptor-α.

Figure 3 Redox signaling in iron (Fe)-induced liver preconditioning is elicited by the cellular labile Fe pool triggering nuclear factor-erythroid 2, signal transducer and activator of transcription 3, and nuclear factor-κB activation and iron-regulatory protein / iron-responsive element post-transcriptional up-regulation with antioxidant and acute-phase responses. BMP: Bone morphogenetic protein; Ft: Ferritin; H₂O₂: Hydrogen peroxide; HO^•: hydroxyl radical; IL-6: Interleukin-6; IRE: Iron-responsive element; IRP: Iron-regulatory protein; Nrf2: Nuclear factor-erythroid 2 related factor 2; ROS: Reactive oxygen species; STAT3: Signal transducer and activator of transcription 3; O₂⁻: Superoxide radical; Tf: Transferring; TNF-α: Tumor necrosis factor-α.