Glucokinase Activator Triggers PERK-UPR Pathway in Diet-Induced Obese Mice via Inducing Hepatic Lipid Accumulation

Background: To investigate the effect of glucokinase activation on glucose and lipid metabolism in diet-induced obese mice. Methods: Mice fed with High-fat-diet (HFD) or control diet for 16 weeks were subjected to glucokinase activator (GKA) or vehicle treatment by gavage for 4 weeks. Glucose tolerance tests were performed to evaluate the glucose-lowering effect of GKA. Hepatic lipid accumulation was assessed by H&E, Oil-red’O staining, and transmission electronic microscopy. The underlying mechanism and subsequent effects of glucokinase activation-induced lipid accumulation was analyzed in liver. Protein levels of related genes were analyzed in mouse livers or AML12 cells. Results: Glucokinase activation improved glucose tolerance and insulin sensitivity in obese mice. Moreover, increased liver weight and TG Content were found in GKA-treated obese mice. Significant hepatic lipid accumulation was observed by multiple assays. RNA sequencing analysis indicated the increased expression of lipogenesis genes and activated PERK-UPR pathway in the liver. Inhibition of the lipogenesis-related gene Acc reduced the lipid levels caused by GKA treatment and alleviated PERK-UPR pathway in AML12 cell line. Conclusions: Glucokinase activation improved glucose tolerance while induced hepatic lipid accumulation through increased lipogenesis, which subsequently triggered PERK-UPR signaling pathway. Disclosure N.Cai: None. L.Zeng: None. X.Chen: None. J.Liu: None. Z.Wen: None. S.Wen: None. W.Zeng: None. S.Lin: None. Y.Chen: None. G.Shi: None. Funding National Natural Science Foundation of China (81770826, 82070811); National Key R&D Program of China (2017YFA0105803); Key Area R&D Program of Guangdong Province (2019B020227003); Sci-Tech Research Development Program of Guangzhou City (202201020497); Natural Science Foundation of Guangdong Province (2018B030311012)