Liraglutide ameliorates lipotoxicity-induced inflammation through the mTORC1 signalling pathway

Lipotoxicity has been implicated in many disease processes, and prolonged exposure to high lipid levels often leads to the activation of a variety of abnormal signals, which in turn leads to the induction of inflammation. The aim of our study was to explore the correlation between mammalian target of rapamycin (mTOR) and inflammation by studying high-fat diet (HFD)-induced non-alcoholic fatty liver disease (NAFLD) in rats and palmitate (PA)-induced inflammation (lipotoxicity) in HepG2 cells. In addition, we investigated whether the glucagon-like peptide-1 (GLP-1) analogue liraglutide can protect rats and HepG2 cells from lipotoxicity. Our results showed that an HFD and PA significantly increased inflammation by activating the mTORC1 pathway in vitro and in vivo. Treatment with rapamycin (an mTOR inhibitor) inhibited some effects of PA on inflammation. Furthermore, we observed that liraglutide inhibited PA-induced inflammation by inactivating mTORC1 signalling molecules. Overall, our findings demonstrated that mTORC1 signalling pathways were involved primarily in high lipid level-induced inflammation. Importantly, liraglutide may protect against lipotoxicity-induced inflammation by regulating mTORC1-dependent pathways.