Wang Xiaoyu, Li Guangbing, Guo Changfa, Zhang Jiayao, Kong Junjie, He Jingyi, Li Feiyu, Liu Yong, Yang Yang, Lu Ziwen, Liu Jun
Department of Hepatobiliary Surgery and Center of Organ Transplantation, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, People's Republic of China.
Department of Hepatobiliary Surgery and Center of Organ Transplantation, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, People's Republic of China.
Diabetes Metab Syndr Obes. 2021 Oct 2;14:4165-4177. doi: 10.2147/DMSO.S321246. eCollection 2021.
The AMP-activated protein kinase alpha (AMPKα) 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.
To investigate whether TMPA could ameliorate liver lipid accumulation under the stimulation of free fatty acids (FFAs) in vitro.
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.
Nur77, AMPKα, 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)-AMPKα (p-AMPKα), 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, AMPKα phosphorylation (p-AMPKα) also showed a higher expression in cytoplasm instead of the nucleus.
TMPA ameliorated lipid accumulation by influencing the stability of Nur77-LKB1 in vitro.
AMP 激活的蛋白激酶α（AMPKα）通路一直被广泛认为是能量代谢的关键因素。2-[2,3,4-三甲氧基-6-(1-辛酰基)苯基]乙酸乙酯（TMPA）是一种新型的 AMPK 激动剂，它影响核受体亚家族 4 组 A 成员 1（Nur77）-丝氨酸-苏氨酸激酶 11（LKB1）在细胞核中的稳定性。最近的一项研究已确定 TMPA 可改善 II 型 db/db 小鼠胰岛素抵抗的降低。然而，TMPA 在肝细胞脂质代谢中的作用尚未阐明。
研究 TMPA 在体外游离脂肪酸（FFA）刺激下是否能改善肝脏脂质积累。
我们评估了高脂饮食小鼠和正常饮食小鼠中 Nur77 和 AMPK 通路的差异。在体外，在 FFA 刺激前将 TMPA 添加到 HepG2 细胞和原代肝细胞中。采用油红 O 染色、尼罗红染色评估脂质沉积。采用蛋白质免疫印迹法和免疫荧光法对相关蛋白进行定量分析。
Nur77、AMPKα、LKB1、3-羟基-3-甲基戊二酰辅酶 A 还原酶（HMGCR）、乙酰辅酶 A 羧化酶磷酸化（p-ACC）和肉碱棕榈酰转移酶 1（CPT1A）在体内表现出显著差异。在 TMPA 的干预下，HepG2 细胞和原代肝细胞的脂质沉积有明显改善，且磷酸化（p）-AMPKα（p-AMPKα）、p-LKB1、p-ACC 和 CPT1A 的表达有所提高。此外，蛋白质免疫印迹法和免疫荧光研究表明，LKB1 在细胞质中的表达显著增加，但在细胞核中的表达减少。此外，AMPKα 磷酸化（p-AMPKα）在细胞质中的表达也高于细胞核。
TMPA 在体外通过影响 Nur77-LKB1 的稳定性改善脂质积累。
