TNIP1 alleviates hepatic ischemia/reperfusion injury via the TLR2-Myd88 pathway

Hepatic ischemia/reperfusion (I/R) injury induces oxidative stress, hepatocyte apoptosis, and release of inflammatory cytokines, which together causes liver damage and even organ dysfunction. TNF-α-induced protein 3-interacting protein 1 (TNIP1) reportedly decreases expression of genes associated with stress response and inflammation. Thus, we investigated the effects of TNIP1 on hepatic cells injury caused by hypoxia/reoxygenation (H/R). Reduced expression of TNIP1 was determined in I/R mice compared to normal mice. Then, TNIP1 transgene mice were used to determine the effects of TNIP1 on mice after treatment for I/R. In the normal transgene (NTG) group, serum liver damage markers alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and gamma glutamyl transferase (GGT) in I/R mice significantly increased compared to the sham-operated mice. However, in the TNIP1 transgene (TNIP1-TG) group, those levels in I/R mice were reduced than that in NTG mice. Additionally, cell viability and apoptosis in the hepatic cell line L02 were detected after H/R treatment, MTT assay showed that cell viability was inhibited after H/R treatment, but reversed after ad-TNIP1 transfection. Cell apoptosis also was inhibited after ad-TNIP1 transfection, as shown by the caspase-3 and caspase-9 levels and Bcl-2 and Bax values. Furthermore, TNIP1 overexpression also attenuated the inflammatory response of L02 cells after H/R treatment. Finally, treatment with TNIP1 reduced the elevated expression of TLR2, TLR4, and Myd88 after H/R injury, but overexpression of TLR4 reversed the effects of TNIP1. In conclusion, TNIP1 may protect H/R-induced hepatic cell injury by inhibiting the TLR4/Myd88 pathway.