AMP-activated protein kinase agonist N(6)-(3-hydroxyphenyl)adenosine protects against fulminant hepatitis by suppressing inflammation and apoptosis

Both AMP-activated protein kinase (AMPK) agonist and inhibitor have been reported to protect against fulminant hepatitis, implying that AMPK may play a complicated role in the development of fulminant hepatitis. In this study, we exploited whether the novel AMPK agonist N(6)-(3-hydroxyphenyl)adenosine (named as M1) exerted protective effects on fulminant hepatitis and whether its beneficial effects were AMPK-dependent. Results showed that intraperitoneal injection of M1 improved liver function, ameliorated liver injury and finally raised the survival rate in d-galactosamine/lipopolysaccharide (GalN/LPS)-treated mice. These beneficial effects of M1 may attribute to the suppression of pro-inflammatory cytokines production and the prevention of hepatocyte apoptosis. Furthermore, M1 pretreatment mitigated LPS-stimulated TLR4 expression and NFκB activation in murine peritoneal macrophages and prevented actinomycin D (Act D)/tumor necrosis factor α (TNFα)-induced apoptosis by promoting protective autophagy in primary hepatocytes. Additionally, M1-induced AMPK activation was responsible both for its anti-inflammatory action in macrophages and for its anti-apoptotic action in hepatocytes. To our surprise, compared with the control AMPKα1(lox/lox)/AMPKα2(lox/lox) mice, liver-specific AMPKα1 knockout (AMPKα1(LS)(−/−)) mice were more sensitive to GalN/LPS administration but not AMPKα2(LS)(−/−)mice, and the beneficial effects of M1 on acute liver failure and the production of pro-inflammatory factors were dampened in AMPKα1(LS)(−/−) mice. Therefore, our study may prove that M1 could be a promising therapeutic agent for fulminant hepatitis, and targeting AMPK may be useful therapeutically in the control of LPS-induced hepatotoxicity.