TNFAIP3 Interacting Protein 3 Is an Activator of Hippo‐YAP Signaling Protecting Against Hepatic Ischemia/Reperfusion Injury

Background and Aims Hepatic ischemia/reperfusion (I/R) injury, a common clinical problem that occurs during liver surgical procedures, causes a large proportion of early graft failure and organ rejection cases. The identification of key regulators of hepatic I/R injury may provide potential strategies to clinically improve the prognosis of liver surgery. Here, we aimed to identify the role of tumor necrosis factor alpha‐induced protein 3–interacting protein 3 (TNIP3) in hepatic I/R injury and further reveal its immanent mechanisms. Approach and Results In the present study, we found that hepatocyte TNIP3 was markedly up‐regulated in livers of both persons and mice subjected to I/R surgery. Hepatocyte‐specific Tnip3 overexpression effectively attenuated I/R‐induced liver necrosis and inflammation, but improved cell proliferation in mice, whereas TNIP3 ablation largely aggravated liver injury. This inhibitory effect of TNIP3 on hepatic I/R injury was found to be dependent on significant activation of the Hippo‐YAP signaling pathway. Mechanistically, TNIP3 was found to directly interact with large tumor suppressor 2 (LATS2) and promote neuronal precursor cell‐expressed developmentally down‐regulated 4–mediated LATS2 ubiquitination, leading to decreased Yes‐associated protein (YAP) phosphorylation at serine 112 and the activated transcription of factors downstream of YAP. Notably, adeno‐associated virus delivered TNIP3 expression in the liver substantially blocked I/R injury in mice. Conclusions TNIP3 is a regulator of hepatic I/R injury that alleviates cell death and inflammation by assisting ubiquitination and degradation of LATS2 and the resultant YAP activation.TNIP3 represents a promising therapeutic target for hepatic I/R injury to improve the prognosis of liver surgery.