Treatment of experimental non-alcoholic steatohepatitis by targeting α7 nicotinic acetylcholine receptor-mediated inflammatory responses in mice

Abstract

Non-alcoholic fatty liver disease (NAFLD) is one of the most common types of liver disease, affecting up to 30% of the general population worldwide. Non-alcoholic steatohepatitis (NASH) is a severe form of NAFLD without any effective therapies available. The present study showed that activation of α7-nicotinic acetylcholine receptor (α7 nAChR) may be a novel potential strategy for NASH therapy. Treatment with the α7 nAChR agonist nicotine for three weeks obviously attenuated hepatic steatosis in a high-fat diet-induced mouse model of NASH. Investigation of the underlying mechanism showed that nicotine reduced the secretion of the pro-inflammatory cytokines tumor necrosis factor α and interleukin 6 in vitro and in vivo. Inflammation is an integral part of NASH and is the most prevalent form of hepatic pathology found in the general population; therefore, the effect of α7 nAChR activation against NASH may be ascribed to its anti-inflammatory effects. In addition, the present study showed that nicotine-stimulated α7 nAChR activation led to a significant downregulation of nuclear factor kappa B (NK-κB) and extracellular signal-regulated kinase (ERK). It therefore appeared that activation of α7 nAChR suppressed the production of pro-inflammatory cytokines through NK-κB and ERK pathways. In conclusion, the present study indicated that targeting α7 nAChR may represent a novel treatment strategy for NASH.