scholarly journals Exendin-4 alleviates hepatic steatosis by lowering FABP1 and raising FOXA1 expression via the Wnt/-catenin signaling pathway

Author(s):  
Olfa Khalifa ◽  
Neyla S. AL-AKl ◽  
Khaoula Errafii ◽  
Abdelilah Arredouani

Abstract Non-alcoholic fatty liver disease (NAFLD) is the leading chronic liver disease worldwide. Agonists of the glucagon-like peptide-1 receptor (GLP-1R), currently approved to treat type 2 diabetes, hold promise to improve steatosis and even steatohepatitis. However, due to their pleiotropic effects, the mechanisms underlying their protective effect on NAFLD remain elusive. We aimed to investigate these mechanisms using an in vitro model of steatosis treated with the GLP-1R agonist Exendin-4 (Ex-4). We established steatotic HepG2 cells by incubating HepG2 cells with 400 µM oleic acid (OA) overnight. Further treatment with 200nM Ex-4 for 3 hours significantly reduced the OA-induced lipid accumulation (p < 0.05). Concomitantly, Ex-4 substantially reduced the expression levels of Fatty Acid-Binding Protein 1 (FABP1) and its primary activator, Forkhead box protein A1 (FOXA1). Interestingly, the silencing of β-catenin with siRNA abolished the effect of Ex-4 on these genes, suggesting dependency on the Wnt/β-catenin pathway. Furthermore, after β-catenin silencing, OA treatment significantly increased the expression of nuclear transcription factors SREBP-1 and TCF4, whereas Ex-4 significantly decreased this upregulation. Our findings suggest that direct activation of GLP-1R by Ex-4 reduces OA-induced steatosis in HepG2 cells by reducing fatty acid uptake via FABP1 downregulation.

Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 425 ◽  
Author(s):  
Marina Parra-Robert ◽  
Eudald Casals ◽  
Nuria Massana ◽  
Muling Zeng ◽  
Meritxell Perramón ◽  
...  

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic accumulation of lipids. Antisteatotic effects of cerium oxide nanoparticles (CeO2NPs) have recently been shown in animal models of liver disease. However, it is unclear whether the activity of CeO2NPs is related solely to the decrease in oxidative stress or, in addition, they directly decrease liver fatty acid accumulation. To address this question, in this work, we used an in vitro model of hepatocellular steatosis, exposing HepG2 cells to oleic and palmitic acid. Cell uptake of CeO2NPs and their effect on oxidative stress and viability of hepatic cells cultured with H2O2 were also evaluated. Results show that CeO2NPs were uptaken by HepG2 cells and reduced oxidative stress and improved cell viability. Treatment with oleic and palmitic acid increased lipogenesis and the content of different fatty acids. CeO2NPs reduced palmitic and stearic acid and most fatty acids consisting of more than 18 carbon atoms. These effects were associated with significant changes in elongase and desaturase activity. In conclusion, CeO2NPs directly protected HepG2 cells from cell injury in oxidative stress conditions and reduced fatty acid content in steatotic conditions by inducing specific changes in fatty acid metabolism, thus showing potential in the treatment of NAFLD.


2018 ◽  
Vol 19 (7) ◽  
pp. 2130
Author(s):  
Chia-Hung Yen ◽  
Hsun-Shuo Chang ◽  
Tsai-Hsun Yang ◽  
Sheng-Fan Wang ◽  
Ho-Cheng Wu ◽  
...  

Non-alcoholic fatty liver disease (NAFLD) has become the most common liver disease in the recent decades in both developed and developing countries, and is predicted to be the major etiology for liver transplantation in the next decade. Thus, pharmacological strategies to treat NAFLD are urgently needed. Natural products are considered an excellent source for drug discovery. By utilizing an image-based high-throughput screening with a library containing 3000 Taiwanese indigenous plant extracts, we discovered that the extract of Syzygium simile leaves (SSLE) has an anti-lipid droplet (LD) accumulation effect in hepatic cell lines. Analyses of the expression profile of genes involved in lipid metabolism revealed that SSLE suppressed the mRNA expression of CD36, fatty acid translocase. In agreement with this observation, we showed that SSLE inhibited CD36 protein expression and fatty acid uptake and has only limited effects on pre-formed LDs. Moreover, SSLE reduced LD accumulation and CD36 expression in enterocyte and macrophage cell lines. In conclusion, our findings suggest that SSLE could serve as a potential source for the discovery of novel therapeutic modalities for NAFLD and that the suppression of CD36 expression and fatty acid uptake could contribute to the lipid-lowering effect of SSLE.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Seung A. Hong ◽  
Ik-Rak Jung ◽  
Sung-E. Choi ◽  
Yoonjung Hwang ◽  
Soo-Jin Lee ◽  
...  

AbstractNon-alcoholic fatty liver disease (NAFLD) is excessive fat build-up in the liver without alcohol consumption and includes hepatic inflammation and damage. Excessive influx of fatty acids to liver from circulation is thought to be a pathogenic cause for the development of NAFLD. Thus, inhibition of fatty acid intake into hepatocyte would be a maneuver for protection from high fat diet (HFD)-induced NAFLD. This study was initiated to determine whether sodium fluorocitrate (SFC) as a fatty acid uptake inhibitor could prevent palmitate-induced lipotoxicity in hepatocytes and protect the mice from HFD-induced NAFLD. SFC significantly inhibited the cellular uptake of palmitate in HepG2 hepatocytes, and thus prevented palmitate-induced fat accumulation and death in these cells. Single treatment with SFC reduced fasting-induced hepatic steatosis in C57BL/6J mice. Concurrent treatment with SFC for 15 weeks in HFD-fed C57BL/6J mice prevented HFD-induced fat accumulation and stress/inflammatory signal activation in the liver. SFC restored HFD-induced increased levels of serum alanine aminotransferase and aspartate aminotransferases as hepatic injury markers in these mice. SFC treatment also improved HFD-induced hepatic insulin resistance, and thus ameliorated HFD-induced hyperglycemia. In conclusion, inhibition of fatty acid mobilization into liver through SFC treatment can be a strategy to protect from HFD-induced NAFLD.


Planta Medica ◽  
2019 ◽  
Vol 85 (09/10) ◽  
pp. 719-728 ◽  
Author(s):  
Wonseok Lee ◽  
Hye Ryoung Koo ◽  
You-Jin Choi ◽  
Jin Gyu Choi ◽  
Myung Sook Oh ◽  
...  

AbstractAbnormal lipid metabolism, such as increased fatty acid uptake and esterification, is associated with nonalcoholic fatty liver disease (NAFLD). The aqueous extract of the aerial part of Angelica tenuissima Nakai (ATX) inhibited high-fat diet–induced hepatic steatosis in mice as well as oleic acid–induced neutral lipid accumulation in HepG2 cells. ATX decreased the mRNA and protein levels of CD36 and diglyceride acyltransferase 2 (DGAT2), the maturation of sterol regulatory element-binding proteins (SREBP), and the expression of the lipogenic target genes fasn and scd1. The ATX components, Z-ligustilide and n-butylidenephthalide, inhibited the expression of FATP5 and DGAT2 and thus oleic acid–induced lipid accumulation in HepG2 cells. These results suggest that ATX and its active components Z-ligustilide and n-butylidenephthalide inhibit fatty acid uptake and esterification in mice and have potential as therapeutics for NAFLD.


2021 ◽  
Vol 12 ◽  
Author(s):  
Karuna Rasineni ◽  
Clayton W. Jordan ◽  
Paul G. Thomes ◽  
Jacy L. Kubik ◽  
Elizabeth M. Staab ◽  
...  

Background: Fatty liver, a major health problem worldwide, is the earliest pathological change in the progression of alcohol-associated (AFL) and non-alcoholic fatty liver disease (NAFL). Though the causes of AFL and NAFL differ, both share similar histological and some common pathophysiological characteristics. In this study, we sought to examine mechanisms responsible for lipid dynamics in liver and adipose tissue in the setting of AFL and NAFL in response to 48 h of fasting.Methods: Male rats were fed Lieber-DeCarli liquid control or alcohol-containing diet (AFL model), chow or high-fat pellet diet (NAFL model). After 6–8 weeks of feeding, half of the rats from each group were fasted for 48 h while the other half remained on their respective diets. Following sacrifice, blood, adipose, and the liver were collected for analysis.Results: Though rats fed AFL and NAFL diets both showed fatty liver, the physiological mechanisms involved in the development of each was different. Here, we show that increased hepatic de novo fatty acid synthesis, increased uptake of adipose-derived free fatty acids, and impaired triglyceride breakdown contribute to the development of AFL. In the case of NAFL, however, increased dietary fatty acid uptake is the major contributor to hepatic steatosis. Likewise, the response to starvation in the two fatty liver disease models also varied. While there was a decrease in hepatic steatosis after fasting in ethanol-fed rats, the control, chow and high-fat diet-fed rats showed higher levels of hepatic steatosis than pair-fed counterparts. This diverse response was a result of increased adipose lipolysis in all experimental groups except fasted ethanol-fed rats.Conclusion: Even though AFL and NAFL are nearly histologically indistinguishable, the physiological mechanisms that cause hepatic fat accumulation are different as are their responses to starvation.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ruiwen Wang ◽  
Zhecheng Wang ◽  
Ruimin Sun ◽  
Rong Fu ◽  
Yu Sun ◽  
...  

Fatty acid β-oxidation is an essential pathogenic mechanism in nonalcoholic fatty liver disease (NAFLD), and TATA-box binding protein associated factor 9 (TAF9) has been reported to be involved in the regulation of fatty acid β-oxidation. However, the function of TAF9 in NAFLD, as well as the mechanism by which TAF9 is regulated, remains unclear. In this study, we aimed to investigate the signaling mechanism underlying the involvement of TAF9 in NAFLD and the protective effect of the natural phenolic compound Danshensu (DSS) against NAFLD via the HDAC1/TAF9 pathway. An in vivo model of high-fat diet (HFD)-induced NAFLD and a palmitic acid (PA)-treated AML-12 cell model were developed. Pharmacological treatment with DSS significantly increased fatty acid β-oxidation and reduced lipid droplet (LD) accumulation in NAFLD. TAF9 overexpression had the same effects on these processes both in vivo and in vitro. Interestingly, the protective effect of DSS was markedly blocked by TAF9 knockdown. Mechanistically, TAF9 was shown to be deacetylated by HDAC1, which regulates the capacity of TAF9 to mediate fatty acid β-oxidation and LD accumulation during NAFLD. In conclusion, TAF9 is a key regulator in the treatment of NAFLD that acts by increasing fatty acid β-oxidation and reducing LD accumulation, and DSS confers protection against NAFLD through the HDAC1/TAF9 pathway.


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