Wnt-β-catenin signaling protects against hepatic ischemia and reperfusion injury in mice.

Abstract

Ischemia and reperfusion injury are common causes of oxidative tissue damage associated with many liver diseases and hepatic surgery. The Wnt-β-catenin signaling pathway is an important regulator of hepatic development, regeneration, and carcinogenesis. However, the role of Wnt signaling in the hepatocellular response to ischemia-reperfusion (I/R) injury has not been determined. Hepatic injury following ischemia or I/R was investigated in hepatocyte-specific, β-catenin-deficient mice, as well as Wnt1-overexpressing and wild-type (control) mice. Wnt-β-catenin signaling was affected by the cellular redox balance in hepatocytes. Following ischemia or I/R, mice with β-catenin-deficient hepatocytes were significantly more susceptible to liver injury. Conversely, mice that overexpressed Wnt1 in hepatocytes were resistant to hepatic I/R injury. Hypoxia inducible factor (HIF)-1α signaling was reduced in β-catenin-deficient liver but increased in hepatocytes that overexpressed Wnt1 under hypoxia and following I/R, indicating an interaction between β-catenin and HIF-1α signaling in the liver. The mechanism by which Wnt signaling protects against liver injury involves the role of β-catenin as a transcriptional coactivator of HIF-1α signaling, which promotes hepatocyte survival under hypoxic conditions. Cellular redox balance affects Wnt-β-catenin signaling, which protects against hypoxia and I/R injury. These findings might be used to develop strategies for protection of hepatocytes, regeneration of liver, and inhibition of carcinogenesis.