OTUD4 alleviates hepatic ischemia-reperfusion injury by suppressing the K63-linked ubiquitination of TRAF6

Hepatic ischemia-reperfusion (IR) injury can cause serious liver damage, leading to liver dysfunction after liver surgery, which is associated with NF-kappa B-mediated inflammation. The K63-linked auto-polyubiquitination of tumor necrosis factor receptor-associated factor 6 (TRAF6) is essential for the activation of NF-kappa B. Here, we found that OTU domain-containing protein 4 (OTUD4), a deubiquitinating enzyme (DUB), interacts with TRAF6 and decreases the K63 auto-polyubiquitination of TRAF6. In addition, the data showed that NF-kappa B activation was impaired and inflammatory factor levels were reduced after overexpressing OTUD4 in a hypoxia/reoxygenation (HR) model and a hepatic IR model. Additionally, the liver inflammatory response and tissue damage were ameliorated in mice overexpressing OTUD4. Taken together, these results show that OTUD4 can negatively regulate NF-kappa B activation by suppressing the K63-linked ubiquitination of TRAF6, thus alleviating hepatic ischemia-reperfusion injury. (C) 2020 Elsevier Inc. All rights reserved.