Li Yang, Ren Luping, Song Guangyao, Zhang Pu, Yang Liying, Chen Xinwei, Yu Xiaolei, Chen Shuchun
Department of Internal Medicine, Hebei Medical University, Shijiazhuang, Hebei 050017, China.
Department of Endocrinology, Hebei General Hospital, Shijiazhuang, Hebei 050051, China.
Endocr Metab Immune Disord Drug Targets. 2019;19(5):632-642. doi: 10.2174/1871530319666190207163325.
Autophagy was recently regarded as a potential mechanism in nonalcoholic fatty liver disease. Silibinin (SIL), a natural flavonoid, has been used to prevent nonalcoholic fatty liver disease, however, the underlying mechanism is unclear. The aim of the present study was to explore the effect of SIL on hepatic steatosis and the possible link with autophagy.
The degree of hepatic steatosis in HepG2 cells was observed by oil-red O staining and triglyceride content. The effect of SIL on autophagy was tested by the Autophagy Detection Kit, and the expression of sterol regulatory element binding protein 1 (srebp-1), Fatty Acid Synthase (Fas), light chain 3, beclin-1, p62, AMP-activated Kinase (AMPK), and mammalian Target Of Rapamycin (mTOR) was examined by western blots.
The lipid accumulation of HepG2 cells increased significantly in the high-fructose group compared to the control group. After SIL intervention, lipid accumulation was decreased. Using a fluorescence microscope, SIL was found to induce autophagy. Compared to control, the expressions of srebp-1, Fas, and phosphorylated-mTOR were increased by high-fructose, while the expressions of light chain 3 and beclin-1 decreased and srebp-1, Fas, and p62 were increased by autophagy inhibition. In contrast, opposite results were found in the SIL intervention group. The protein content of phosphorylated- mTOR was decreased, while phosphorylated-AMPK was increased in the SIL group compared to the high-fructose group.
SIL can reduce lipid accumulation in HepG2 cells exposed to high-fructose by inducing autophagy. The AMPK/mTOR signaling pathway could be one of the underlying molecular mechanisms.
自噬最近被认为是非酒精性脂肪性肝病的一种潜在机制。水飞蓟宾（SIL）是一种天然黄酮类化合物，已被用于预防非酒精性脂肪性肝病，然而，其潜在机制尚不清楚。本研究的目的是探讨SIL对肝脂肪变性的影响以及与自噬的可能联系。
通过油红O染色和甘油三酯含量观察HepG2细胞中肝脂肪变性的程度。使用自噬检测试剂盒检测SIL对自噬的影响，并通过蛋白质免疫印迹法检测固醇调节元件结合蛋白1（srebp-1）、脂肪酸合酶（Fas）、轻链3、beclin-1、p62、腺苷酸活化蛋白激酶（AMPK）和哺乳动物雷帕霉素靶蛋白（mTOR）的表达。
与对照组相比，高果糖组HepG2细胞的脂质积累显著增加。SIL干预后，脂质积累减少。使用荧光显微镜发现SIL可诱导自噬。与对照组相比，高果糖使srebp-1、Fas和磷酸化mTOR的表达增加，而自噬抑制使轻链3和beclin-1的表达降低，srebp-1、Fas和p62的表达增加。相反，在SIL干预组中发现了相反的结果。与高果糖组相比，SIL组磷酸化mTOR蛋白含量降低，而磷酸化AMPK增加。
SIL可通过诱导自噬减少高果糖处理的HepG2细胞中的脂质积累。AMPK/mTOR信号通路可能是其潜在的分子机制之一。
