Rictor Deficiency Aggravates Hepatic Ischemia/Reperfusion Injury in Mice by Suppressing Autophagy and Regulating MAPK Signaling.

BACKGROUND/AIMS: The role of Rictor in hepatic ischemia/reperfusion (I/R) injury remains unknown. Here, we comprehensively examined the role of Rictor in hepatic I/R injury.

METHODS: We studied the expression of Rictor during hepatic I/R injury. The regulatory effects of Rictor on inflammatory responses, cytokine and chemokine release, apoptotic and anti-apoptotic responses, and autophagy induction during hepatic I/R injury were identified via the shRNA-mediated knockdown of Rictor. Subsequently, we collected the liver and blood samples of these mice to evaluate liver injury, mRNA and protein levels. Additionally, the signaling pathways induced by Rictor were investigated. Furthermore, the extent of activation of MAPKs in response to Rictor deficiency was investigated in lipopolysaccharide (LPS)-treated RAW264.7 cells. The mRNA expression levels were analyzed by real-time PCR, and the protein expression levels were analyzed using Western blot, immunofluorescence staining and enzyme-linked immunosorbent assay (ELISA).

RESULTS: The expression of Rictor was increased during hepatic I/R injury in vivo and hypoxia/reoxygenation (H/R) injury in vitro. Rictor deficiency enhanced the extent of liver injury by increasing macrophage and neutrophil infiltration, promoting cytokine and chemokine release, aggravating hepatocyte apoptosis, suppressing anti-apoptotic responses, and inhibiting autophagy induction during both hepatic I/R and H/R injury. Rictor was associated with the activation of hepatic I/R injury-induced MAPK signaling. In addition, Rictor deficiency affected MAPK activation in LPS-treated RAW264.7 cells.

CONCLUSION: Rictor can substantially ameliorate I/R-induced liver injury. Therefore, our findings strongly suggest a therapeutic value of the Rictor/mTORC2 axis in hepatic I/R injury.