AK-1, a Sirt2 inhibitor, alleviates carbon tetrachloride-induced hepatotoxicity in vivo and in vitro

Abstract

Background/Aim: Acute liver injury (ALI) is a life-threatening clinical syndrome that is usually caused by toxic chemicals, drugs, or pathogen infections. Sirtuin2 (Sirt2), an NAD+-dependent deacetylase, appears to play detrimental roles in liver injury. Here, we evaluated the therapeutic application targeting Sirt2 in carbon tetrachloride (CCl4)-induced ALI, by using AK-1 (a Sirt2 inhibitor).Methods: For in vivo experiments, a single injection of CCl4 was used to induce ALI. One hour later, mice were intraperitoneally injected with AK-1 and were sacrificed 24 h after CCl4 administration. For in vitro experiments, primary mouse hepatocytes were used to determine the effects of AK-1 on oxidative stress and hepatocellular death induced by CCl4.Results: AK-1 alleviated CCl4-induced ALI as confirmed by histopathologic analysis, and decreased levels of serum biochemicals and inflammatory cytokines. Although it barely affected the expression of hepatic cytochrome P450 enzymes, AK-1 attenuated CCl4-induced oxidative stress and its related cell death. Mechanistically, Sirt2 inhibition significantly increased the nuclear protein level of nuclear factor erythroid 2-related factor 2 (Nrf2), and meanwhile decreased phosphorylation of c-Jun N-terminal kinases (JNK), in normal and injured livers. Similar results were observed in vitro. AK-1 significantly attenuated CCl4-induced cytotoxicity and oxidative stress by up-regulating the activity of Nrf2, and down-regulating JNK signaling in hepatocytes.Conclusions: Our results suggest that AK-1 treatment attenuated oxidative stress and cell death in the ALI model, at least partially, via activating Nrf2 and inhibiting JNK signaling, and that Sirt2 inhibition might be a potential approach to cure ALI.