Lycopus lucidus Turcz. ex Benth. Attenuates free fatty acid-induced steatosis in HepG2 cells and non-alcoholic fatty liver disease in high-fat diet-induced obese mice.
Lee Mi Ra,Yang Hye Jin,Park Kwang Il,Ma Jin Yeul
Phytomedicine : international journal of phytotherapy and phytopharmacology
BACKGROUND:Non-alcoholic fatty liver disease (NAFLD) is closely related to metabolic diseases such as obesity and insulin resistance. PURPOSE:We studied whether an ethanol extract of Lycopus lucidus Turcz. ex Benth (LLE) exhibited effects on lipid metabolism in NAFLD. STUDY DESIGN:An in vitro modelwas established by treatment of HepG2 cells with a 1 mM free fatty acid (FFA) mixture (oleic acid/palmitic acid, 2:1). C57BL/6 mice were fed a high-fat diet (HFD; 60 kcal% fat) for 14 weeks to induce obesity and were treated with or without LLE (100 or 200 mg/kg daily by oral gavage). METHODS:HepG2 cells were exposed to 1 mM FFA, with or without LLE (250 - 1000 mg/ml). Intracellular lipid contents were measured by Oil Red O staining and a Nile Red assay. The body weight, relative liver weight, hepatic lipids, triglycerides (TGs), and total cholesterol (TC) were measured in the mice. Serum alanine aminotransferase (ALT), TG, TC, glucose, insulin, leptin, and tumor necrosis factor-alpha (TNF-α) levels were determined by biochemical or enzyme-linked immunosorbent assays. Histologic analysis was performed in the liver. Western blotting and quantitative real-time polymerase chain reaction were used to analyze the expression of key enzymes of hepatic lipid metabolism. RESULTS:LLE significantly decreased the intracellular lipid accumulation in FFA-treated HepG2 cells. LLE not only remarkably decreased the expression of lipogenesis genes but also increased β-oxidation in FFA-induced HepG2 cells. In the in vivo study, LLE treatment significantly decreased the body weight, relative liver weight, serum ALT, TC, and low-density lipoprotein cholesterol, as well as the serum glucose, insulin, leptin, and TNF-α levels in HFD-fed mice. The hepatic TG and TC contents were significantly reduced in the LLE-treated groups. Western blot analysis showed that the expression of sterol-regulatory element-binding protein 1 decreased, while that of phosphorylated AMP-activated protein kinase and peroxisome proliferator-activated receptor α increased in the LLE-treated mice. CONCLUSION:These results suggest that LLE may exert protective effects against NAFLD-related obesity and metabolic disease.
Kangtaizhi Granule Alleviated Nonalcoholic Fatty Liver Disease in High-Fat Diet-Fed Rats and HepG2 Cells via AMPK/mTOR Signaling Pathway.
Zhang Jiaxin,Du Haixia,Shen Menglan,Zhao Zhengqi,Ye Xinmiao
Journal of immunology research
Kangtaizhi granule (KTZG) is a Chinese medicine compound prescription and has been proven to be effective in nonalcoholic fatty liver disease (NAFLD) treatment clinically. However, the underlying mechanisms under this efficacy are rather elusive. In the present study, network pharmacology and HPLC analysis were performed to identify the chemicals of KTZG and related target pathways for NAFLD treatment. Network pharmacology screened 42 compounds and 79 related targets related to NAFLD; HPLC analysis also confirmed six compounds in KTZG. Further experiments were also performed. In an study, SD rats were randomly divided into five groups: control (rats fed with normal diet), NAFLD (rats fed with high-fat diet), and KTZG 0.75, 1.5, and 3 groups (NAFLD rats treated with KTZG 0.75, 1.5, and 3 g/kg, respectively). Serum lipids were biochemically determined; hepatic steatosis and lipid accumulation were evaluated with HE and oil red O staining. In an study, HepG2 cells were incubated with 1 mM FFA to induce lipid accumulation with or without KTZG treatment. MTT assay, intracellular TG level, oil red O staining, and glucose uptake in cells were detected. Western blotting and immunohistochemical and immunofluorescence staining were also performed to determine the expression of lipid-related genes PPAR-, SREBP-1, p-AKT, FAS, and SIRT1 and genes in the AMPK/mTOR signaling pathway. In high-fat diet-fed rats, KTZG treatment significantly improved liver organ index and serum lipid contents of TG, TC, LDL-C, HDL-C, ALT, and AST significantly; HE and oil red O staining also showed that KTZG alleviated hepatic steatosis and liver lipid accumulation. In FFA-treated HepG2 cells, KTZG treatment decreased the intracellular TG levels, lipid accumulation, and attenuated glucose uptake significantly. More importantly, lipid-related genes PPAR-, SREBP-1, p-AKT, FAS, and SIRT1 expressions were ameliorated with KTZG treatment in high-fat diet-fed rats and FFA-induced HepG2 cells. The p-AMPK and p-mTOR expressions in the AMPK/mTOR signaling pathway were also modified with KTZG treatment in high-fat diet-fed rats and HepG2 cells. These results indicated that KTZG effectively ameliorated lipid accumulation and hepatic steatosis to prevent NAFLD in high-fat diet-fed rats and FFA-induced HepG2 cells, and this effect was associated with the AMPK/mTOR signaling pathway. Our results suggested that KTZG might be a potential therapeutic agent for the prevention of NAFLD.
Oleic Acid and Eicosapentaenoic Acid Reverse Palmitic Acid-induced Insulin Resistance in Human HepG2 Cells via the Reactive Oxygen Species/JUN Pathway.
Genomics, proteomics & bioinformatics
Oleic acid (OA), a monounsaturated fatty acid (MUFA), has previously been shown to reverse saturated fatty acid palmitic acid (PA)-induced hepatic insulin resistance (IR). However, its underlying molecular mechanism is unclear. In addition, previous studies have shown that eicosapentaenoic acid (EPA), a ω-3 polyunsaturated fatty acid (PUFA), reverses PA-induced muscle IR, but whether EPA plays the same role in hepatic IR and its possible mechanism involved need to be further clarified. Here, we confirmed that EPA reversed PA-induced IR in HepG2 cells and compared the proteomic changes in HepG2 cells after treatment with different free fatty acids (FFAs). A total of 234 proteins were determined to be differentially expressed after PA+OA treatment. Their functions were mainly related to responses to stress and endogenous stimuli, lipid metabolic process, and protein binding. For PA+EPA treatment, the PA-induced expression changes of 1326 proteins could be reversed by EPA, 415 of which were mitochondrial proteins, with most of the functional proteins involved in oxidative phosphorylation (OXPHOS) and tricarboxylic acid (TCA) cycle. Mechanistic studies revealed that the protein encoded by JUN and reactive oxygen species (ROS) play a role in OA- and EPA-reversed PA-induced IR, respectively. EPA and OA alleviated PA-induced abnormal adenosine triphosphate (ATP) production, ROS generation, and calcium (Ca) content. Importantly, HO-activated production of ROS increased the protein expression of JUN, further resulting in IR in HepG2 cells. Taken together, we demonstrate that ROS/JUN is a common response pathway employed by HepG2 cells toward FFA-regulated IR.
S-petasin inhibits lipid accumulation in oleic acid-induced HepG2 cells through activation of the AMPK signaling pathway.
Guo Lu,Kang Jum Soon,Park Young Hoon,Je Beong Il,Lee Yong Jae,Kang Nam Jun,Park Sun Young,Hwang Dae Youn,Choi Young Whan
Food & function
Nonalcoholic fatty liver disease (NAFLD) has become one of the most common medical problems. Inhibition of lipogenesis and promotion of lipolysis are two ways to prevent NAFLD. In this study, oleic acid-induced HepG2 cells are used as a NAFLD cell model to test whether s-petasin exerts inhibition of lipogenesis and promotion of the lipolysis effect. The results showed that s-petasin significantly inhibited the lipid level in oleic acid-induced HepG2 cells. Moreover, results showed that the triacylglycerol level was reduced by s-petasin in oleic acid-induced HepG2 cells. Western blot assay revealed that s-petasin stimulated phosphorylation of AMPKα and ACCα. The results also demonstrated that s-petasin can inhibit lipogenesis and enhance triacylglycerol turnover by down-regulation of FAS and SCD-1 and up-regulation of ATGL and HSL through the AMPK signaling-dependent regulation of transcriptional factors, FKHR and SREBP-1. This in vitro study indicates that s-petasin has potential as a candidate compound for NAFLD therapy.
Tetrahydrocurcumin ameliorates free fatty acid-induced hepatic steatosis and improves insulin resistance in HepG2 cells.
Chen Jin-Wun,Kong Zwe-Ling,Tsai Mei-Ling,Lo Chih-Yu,Ho Chi-Tang,Lai Ching-Shu
Journal of food and drug analysis
Elevated levels of free fatty acids (FFAs) in the liver, resulting from either increased lipolysis or imbalanced FFAs flux, is a key pathogenic factor of hepatic steatosis. This study was conducted to examine the therapeutic effect of tetrahydrocurcumin (THC), a naturally occurring curcuminoid and a metabolite of curcumin, on oleic acid (OA)-induced steatosis in human hepatocellular carcinoma cells and to elucidate the underlying mechanism. HepG2 cells were incubated with OA to induce steatosis, and then treated with various concentrations of THC. The results showed that THC treatment significantly decreased lipid accumulation in OA-treated HepG2 cells, possibly, by inhibiting the expression of the lipogenic proteins, sterol regulatory element-binding protein 1 (SREBP-1c), peroxisome proliferator-activated receptor gamma (PPARγ), fatty acid synthase (FAS), and fatty acid-binding protein 4 (FABP4). Moreover, THC attenuated OA-induced hepatic lipogenesis in an adenosine monophosphate-activated protein kinase (AMPK)-dependent manner, which was reversed by pretreatment with an AMPK inhibitor. THC promoted lipolysis and upregulated the expression of genes involved in β-oxidation. Glucose uptake and insulin signaling impaired in HepG2 cells incubated with OA were abated by THC treatment, including phosphorylation of the insulin receptor substrate 1 (IRS-1)/phosphoinositide 3-kinase (PI3K)/Akt and downstream signaling pathways, forkhead box protein O1 (FOXO1) and glycogen synthase kinase 3 β (GSK3β), which are involved in gluconeogenesis and glycogen synthesis, respectively. Altogether, these results demonstrated the novel therapeutic benefit of THC against hepatic steatosis and, consequently, a potential treatment for non-alcoholic fatty liver disease (NAFLD).