Ethyl 2-[2,3,4-Trimethoxy-6-(1-Octanoyl)Phenyl] Acetate (Tmpa) Ameliorates Lipid Accumulation By Disturbing The Combination Of Lkb1 With Nur77 And Activating The Ampk Pathway In Hepg2 Cells And Mice Primary Hepatocytes

Background: The AMP-activated protein kinase alpha (AMPK alpha) pathway has widely been considered a key factor in energy metabolism. Ethyl 2-[2,3,4-trimethoxy-6-(1-octanoyl) phenyl] acetate (TMPA) is a novel AMPK agonist, which influences the stability of Nuclear Receptor Subfamily 4, Group A, Member 1 (Nur77)-serine-threonine kinase 11 (LKB1) in the nucleus. A recent study has determined that TMPA can ameliorate the reduction of insulin resistance in type II db/db mice. However, the role of TMPA in hepatocyte lipid metabolism has not been elucidated. Objective: To investigate whether TMPA could ameliorate liver lipid accumulation under the stimulation of free fatty acids (FFAs) in vitro. Methods: We evaluated differences of Nur77 and AMPK pathway in mice fed a high-fat diet and those fed a normal diet. In vitro, TMPA was added to HepG2 cells and primary hepatocytes before FFAs stimulation. Oil red O staining, Nile red staining were used to evaluate lipid deposition. Western blot and immunofluorescence were used to quantify related proteins. Results: Nur77, AMPK alpha, LKB1, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), acetyl-CoA carboxylase phosphorylation (p-ACC), and carnitine palmitoyltransferase 1 (CPT1A) showed significant differences in vivo. Under the intervention of TMPA, HepG2 cells and primary hepatocytes showed considerable amelioration of lipid deposition and improved the expression of phosphorylated (p)-AMPK alpha (p-AMPK alpha), p-LKB1, p-ACC, and CPT1A. Furthermore, Western blotting and immunofluorescence studies indicated that LKB1 dramatically increased expression in the cytoplasm but decreased in the nucleus. Further, AMPK alpha phosphorylation (p-AMPK alpha) also showed a higher expression in cytoplasm instead of the nucleus. Conclusion: TMPA ameliorated lipid accumulation by influencing the stability of Nur77LKB1 in vitro.