scholarly journals Poria cocus Wolf Extract Ameliorates Hepatic Steatosis through Regulation of Lipid Metabolism, Inhibition of ER Stress, and Activation of Autophagy via AMPK Activation

2019 ◽  
Vol 20 (19) ◽  
pp. 4801 ◽  
Author(s):  
Ji-Hyun Kim ◽  
Hyun A Sim ◽  
Dae Young Jung ◽  
Eun Yeong Lim ◽  
Yun Tai Kim ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Er Stress ◽  
Hepatic Steatosis ◽  
Fatty Acid Oxidation ◽  
Hepg2 Cells ◽  
Acid Oxidation ◽  
Pachymic Acid ◽  
Metabolism Inhibition

Poria cocos Wolf (PCW) is an edible, pharmaceutical mushroom with remarkable biological properties including anti-tumor, anti-inflammation, anti-oxidation, anti-ageing, and anti-diabetic effects. In the current study, we investigated the effects of PCW extract on hepatic steatosis under in vitro and in vivo conditions, and elucidated the underlying mechanisms. In this study, a mixture of HepG2 cells treated with free fatty acid (FFA)—palmitic and oleic acid—and high-fat diet (HFD)-fed obese mice were used; in this background, the triglyceride (TG) levels in HepG2 cells and mice liver were measured, and the expression levels of genes associated with lipogenesis, fatty acid oxidation, endoplasmic reticulum (ER) stress, and autophagy were determined. Treatment of HepG2 cells with FFA enhanced intracellular TG levels in HepG2 cells, but co-treatment with PCW significantly attenuated the TG levels. Notably, PCW significantly enhanced the phosphorylation of AMP-activated protein kinase (AMPK), acetyl-CoA carboxylase (ACC), and sterol regulatory element-binding protein-1c (SREBP-1c) in FFA-treated HepG2 cells. PCW downregulated the expression of lipogenesis-related genes, but upregulated the expression of genes associated with fatty acid oxidation. Further, PCW inhibited FFA-induced expression of ER stress markers and induced autophagy proteins. However, inhibition of AMPK significantly attenuated the beneficial effects of PCW in HepG2 cells. Moreover, PCW efficiently decreased HFD-induced hepatic TG accumulation in vivo and increased the phosphorylation of hepatic AMPK. Three compounds present in PCW including poricoic acid, pachymic acid, and ergosterol, significantly decreased FFA-induced increase in intracellular TG levels, consistent with increased AMPK phosphorylation, suggesting that poricoic acid, pachymic acid, and ergosterol are responsible for PCW-mediated amelioration of hepatic steatosis. Taken together, these results demonstrated that PCW ameliorates hepatic steatosis through the regulation of lipid metabolism, inhibition of ER stress, and activation of autophagy in an AMPK-dependent manner. This suggested that PCW can be potentially used for the treatment of hepatic steatosis.

scholarly journals A Combination of Caffeine, Arginine, Soy Isoflavones, and l-Carnitine Enhances Both Lipolysis and Fatty Acid Oxidation in 3T3-L1 and HepG2 Cells in Vitro and in KK Mice in Vivo

2007 ◽  
Vol 137 (10) ◽  
pp. 2252-2257 ◽  
Author(s):  
Shinji Murosaki ◽  
Tae Ryong Lee ◽  
Koutarou Muroyama ◽  
Eui Seok Shin ◽  
Si Young Cho ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Hepg2 Cells ◽  
Soy Isoflavones ◽  
Acid Oxidation ◽  
Kk Mice

scholarly journals CDKN2A/p16INK4a suppresses hepatic fatty acid oxidation through the AMPKα2-SIRT1-PPARα signaling pathway

2020 ◽  
Vol 295 (50) ◽  
pp. 17310-17322
Author(s):  
Yann Deleye ◽  
Alexia Karen Cotte ◽  
Sarah Anissa Hannou ◽  
Nathalie Hennuyer ◽  
Lucie Bernard ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Fatty Acid Oxidation ◽  
Lipid Droplet ◽  
Acid Oxidation ◽  
Hepatic Lipid Metabolism ◽  
Hepatic Lipid ◽  
Hepatic Fatty Acid Oxidation

In addition to their well-known role in the control of cellular proliferation and cancer, cell cycle regulators are increasingly identified as important metabolic modulators. Several GWAS have identified SNPs near CDKN2A, the locus encoding for p16INK4a (p16), associated with elevated risk for cardiovascular diseases and type-2 diabetes development, two pathologies associated with impaired hepatic lipid metabolism. Although p16 was recently shown to control hepatic glucose homeostasis, it is unknown whether p16 also controls hepatic lipid metabolism. Using a combination of in vivo and in vitro approaches, we found that p16 modulates fasting-induced hepatic fatty acid oxidation (FAO) and lipid droplet accumulation. In primary hepatocytes, p16-deficiency was associated with elevated expression of genes involved in fatty acid catabolism. These transcriptional changes led to increased FAO and were associated with enhanced activation of PPARα through a mechanism requiring the catalytic AMPKα2 subunit and SIRT1, two known activators of PPARα. By contrast, p16 overexpression was associated with triglyceride accumulation and increased lipid droplet numbers in vitro, and decreased ketogenesis and hepatic mitochondrial activity in vivo. Finally, gene expression analysis of liver samples from obese patients revealed a negative correlation between CDKN2A expression and PPARA and its target genes. Our findings demonstrate that p16 represses hepatic lipid catabolism during fasting and may thus participate in the preservation of metabolic flexibility.

scholarly journals Overexpression of Nudt7 decreases bile acid levels and peroxisomal fatty acid oxidation in the liver

2019 ◽  
Vol 60 (5) ◽  
pp. 1005-1019 ◽  
Author(s):  
Stephanie A. Shumar ◽  
Evan W. Kerr ◽  
Paolo Fagone ◽  
Aniello M. Infante ◽  
Roberta Leonardi
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Bile Acid ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Nudix Hydrolase ◽  
Peroxisomal Fatty Acid Oxidation ◽  
Chain Acyl ◽  
Peroxisomal Fatty Acid

Lipid metabolism requires CoA, an essential cofactor found in multiple subcellular compartments, including the peroxisomes. In the liver, CoA levels are dynamically adjusted between the fed and fasted states. Elevated CoA levels in the fasted state are driven by increased synthesis; however, this also correlates with decreased expression of Nudix hydrolase (Nudt)7, the major CoA-degrading enzyme in the liver. Nudt7 resides in the peroxisomes, and we overexpressed this enzyme in mouse livers to determine its effect on the size and composition of the hepatic CoA pool in the fed and fasted states. Nudt7 overexpression did not change total CoA levels, but decreased the concentration of short-chain acyl-CoAs and choloyl-CoA in fasted livers, when endogenous Nudt7 activity was lowest. The effect on these acyl-CoAs correlated with a significant decrease in the hepatic bile acid content and in the rate of peroxisomal fatty acid oxidation, as estimated by targeted and untargeted metabolomics, combined with the measurement of fatty acid oxidation in intact hepatocytes. Identification of the CoA species and metabolic pathways affected by the overexpression on Nudt7 in vivo supports the conclusion that the nutritionally driven modulation of Nudt7 activity could contribute to the regulation of the peroxisomal CoA pool and peroxisomal lipid metabolism.

scholarly journals Inhibition of fatty acid oxidation enhances oxidative protein folding and protects hepatocytes from endoplasmic reticulum stress

2012 ◽  
Vol 23 (5) ◽  
pp. 811-819 ◽  
Author(s):  
Heather M. Tyra ◽  
Douglas R. Spitz ◽  
D. Thomas Rutkowski
Keyword(s):  
Endoplasmic Reticulum ◽  
Fatty Acid ◽  
Er Stress ◽  
Fatty Acid Oxidation ◽  
Protein Misfolding ◽  
Stress Sensitivity ◽  
Acid Oxidation ◽  
The Unfolded Protein Response

The unfolded protein response (UPR) signals protein misfolding in the endoplasmic reticulum (ER) to effect gene expression changes and restore ER homeostasis. Although many UPR-regulated genes encode ER protein processing factors, others, such as those encoding lipid catabolism enzymes, seem unrelated to ER function. It is not known whether UPR-mediated inhibition of fatty acid oxidation influences ER function or, if so, by what mechanism. Here we demonstrate that pharmacological or genetic inhibition of fatty acid oxidation renders liver cells partially resistant to ER stress–induced UPR activation both in vitro and in vivo. Reduced stress sensitivity appeared to be a consequence of increased cellular redox potential as judged by an elevated ratio of oxidized to reduced glutathione and enhanced oxidative folding in the ER. Accordingly, the ER folding benefit of inhibiting fatty acid (FA) oxidation could be phenocopied by manipulating glutathione recycling during ER stress. Conversely, preventing cellular hyperoxidation with N-acetyl cysteine partially negated the stress resistance provided by blocking FA oxidation. Our results suggest that ER stress can be ameliorated through alteration of the oxidizing environment within the ER lumen, and they provide a potential logic for the transient regulation of metabolic pathways by the UPR during stress.

scholarly journals Glucagon-induced extracellular cAMP regulates hepatic lipid metabolism

2017 ◽  
Vol 234 (2) ◽  
pp. 73-87 ◽  
Author(s):  
Sihan Lv ◽  
Xinchen Qiu ◽  
Jian Li ◽  
Jinye Liang ◽  
Weida Li ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Hepatic Steatosis ◽  
Fatty Acid Oxidation ◽  
Lipid Homeostasis ◽  
Acid Oxidation ◽  
Intracellular Camp ◽  
Hepatic Lipid Metabolism ◽  
Hepatic Lipid ◽  
Extracellular Camp

Hormonal signals help to maintain glucose and lipid homeostasis in the liver during the periods of fasting. Glucagon, a pancreas-derived hormone induced by fasting, promotes gluconeogenesis through induction of intracellular cAMP production. Glucagon also stimulates hepatic fatty acid oxidation but the underlying mechanism is poorly characterized. Here we report that following the acute induction of gluconeogenic genes Glucose 6 phosphatase (G6Pase) and Phosphoenolpyruvate carboxykinase (Pepck) expression through cAMP-response element-binding protein (CREB), glucagon triggers a second delayed phase of fatty acid oxidation genes Acyl-coenzyme A oxidase (Aox) and Carnitine palmitoyltransferase 1a (Cpt1a) expression via extracellular cAMP. Increase in extracellular cAMP promotes PPARα activity through direct phosphorylation by AMP-activated protein kinase (AMPK), while inhibition of cAMP efflux greatly attenuates Aox and Cpt1a expression. Importantly, cAMP injection improves lipid homeostasis in fasted mice and obese mice, while inhibition of cAMP efflux deteriorates hepatic steatosis in fasted mice. Collectively, our results demonstrate the vital role of glucagon-stimulated extracellular cAMP in the regulation of hepatic lipid metabolism through AMPK-mediated PPARα activation. Therefore, strategies to improve cAMP efflux could serve as potential new tools to prevent obesity-associated hepatic steatosis.

scholarly journals Gomisin N Alleviates Ethanol-Induced Liver Injury through Ameliorating Lipid Metabolism and Oxidative Stress

2018 ◽  
Vol 19 (9) ◽  
pp. 2601 ◽  
Author(s):  
Arulkumar Nagappan ◽  
Dae Jung ◽  
Ji-Hyun Kim ◽  
Hoyoung Lee ◽  
Myeong Jung
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Fatty Acid ◽  
Liver Injury ◽  
Hepatic Steatosis ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Antioxidant Genes ◽  
Gomisin N

Gomisin N (GN), a lignan derived from Schisandra chinensis, has been shown to possess antioxidant, anti-inflammatory, and anticancer properties. In the present study, we investigated the protective effect of GN against ethanol-induced liver injury using in vivo and in vitro experiments. Histopathological examination revealed that GN administration to chronic-binge ethanol exposure mice significantly reduced ethanol-induced hepatic steatosis through reducing lipogenesis gene expression and increasing fatty acid oxidation gene expression, and prevented liver injury by lowering the serum levels of aspartate transaminase and alanine transaminase. Further, it significantly inhibited cytochrome P450 2E1 (CYP2E1) gene expression and enzyme activity, and enhanced antioxidant genes and glutathione level in hepatic tissues, which led to decreased hepatic malondialdehyde levels. It also lowered inflammation gene expression. Finally, GN administration promoted hepatic sirtuin1 (SIRT1)-AMP-activated protein kinase (AMPK) signaling in ethanol-fed mice. Consistent with in vivo data, treatment with GN decreased lipogenesis gene expression and increased fatty acid oxidation gene expression in ethanol-treated HepG2 cells, thereby preventing ethanol-induced triglyceride accumulation. Furthermore, it inhibited reactive oxygen species generation by downregulating CYP2E1 and upregulating antioxidant gene expression, and suppressed inflammatory gene expression. Moreover, GN prevented ethanol-mediated reduction in SIRT1 and phosphorylated AMPK. These findings indicate that GN has therapeutic potential against alcoholic liver disease through inhibiting hepatic steatosis, oxidative stress and inflammation.

scholarly journals Nordihydroguaiaretic acid improves metabolic dysregulation and aberrant hepatic lipid metabolism in mice by both PPARα-dependent and -independent pathways

2013 ◽  
Vol 304 (1) ◽  
pp. G72-G86 ◽  
Author(s):  
Haiyan Zhang ◽  
Wen-Jun Shen ◽  
Yuan Cortez ◽  
Fredric B. Kraemer ◽  
Salman Azhar
Keyword(s):  
Gene Expression ◽  
Fatty Acid ◽  
Lipid Metabolism ◽  
Hepatic Steatosis ◽  
Fatty Acid Oxidation ◽  
Nordihydroguaiaretic Acid ◽  
Acid Oxidation ◽  
Hepatic Gene Expression ◽  
Creosote Bush ◽  
Fatty Acid Catabolism

Creosote bush-derived nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, possesses antioxidant properties and functions as a potent antihyperlipidemic agent in rodent models. Here, we examined the effect of chronic NDGA treatment of ob/ob mice on plasma dyslipidemia, hepatic steatosis, and changes in hepatic gene expression. Feeding ob/ ob mice a chow diet supplemented with either low (0.83 g/kg diet) or high-dose (2.5 g/kg diet) NDGA for 16 wk significantly improved plasma triglyceride (TG), inflammatory chemokine levels, hyperinsulinemia, insulin sensitivity, and glucose intolerance. NDGA treatment caused a marked reduction in liver weight and TG content, while enhancing rates of fatty acid oxidation. Microarray analysis of hepatic gene expression demonstrated that NDGA treatment altered genes for lipid metabolism, with genes involved in fatty acid catabolism most significantly increased. NDGA upregulated the mRNA and nuclear protein levels of peroxisome proliferator-activated receptor α (PPARα), and the activated (phosphorylated) form of AMP-activated kinase. NDGA increased PPARα promoter activity in AML12 hepatocytes and also prevented the fatty acid suppression of PPARα expression. In contrast, PPARα siRNA abrogated the stimulatory effect of NDGA on fatty acid catabolism. Likewise, no stimulatory effect of NDGA on hepatic fatty acid oxidation was observed in the livers of PPARα-deficient mice, but the ability of NDGA to reverse fatty liver conditions was unaffected. In conclusion, the beneficial actions of NDGA on dyslipidemia and hepatic steatosis in ob/ob mice are exerted primarily through enhanced fatty acid oxidation via PPARα-dependent pathways. However, PPARα-independent pathways also contribute to NDGA's action to ameliorate hepatic steatosis.

scholarly journals Stimulation of Lipogenesis as Well as Fatty Acid Oxidation Protects against Palmitate-Induced INS-1 β-Cell Death

Endocrinology ◽  
2011 ◽  
Vol 152 (3) ◽  
pp. 816-827 ◽  
Author(s):  
Sung-E. Choi ◽  
Ik-Rak Jung ◽  
Youn-Jung Lee ◽  
Soo-Jin Lee ◽  
Ji-Hyun Lee ◽  
...  
Keyword(s):  
Cell Death ◽  
Fatty Acid ◽  
Lipid Metabolism ◽  
Er Stress ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Protective Effects ◽  
Β Cells ◽  
Β Cell ◽  
Stimulation Of

Saturated fatty acids are generally cytotoxic to β-cells. Accumulation of lipid intermediates and subsequent activation of lipid-mediated signals has been suggested to play a role in fatty acid-induced toxicity. To determine the effects of lipid metabolism in fatty acid-induced toxicity, lipid metabolism was modulated by up- and down-regulation of a lipogenic or fatty acid oxidation pathway, and the effects of various modulators on palmitate (PA)-induced INS-1 β-cell death were then evaluated. Treatment with the liver X receptor agonist T0901317 reduced PA-induced INS-1 cell death, regardless of its enhanced lipogenic activity. Furthermore, transient expression of a lipogenic transcription factor sterol regulatory element binding protein-1c (SREBP-1c) was also protective against PA-induced cytotoxicity. In contrast, knockdown of SREBP-1c or glycerol-3-phosphate acyltransferase 1 significantly augmented PA-induced cell death and reduced T0901317-induced protective effects. Conversely, T0901317 increased carnitine PA transferease-1 (CPT-1) expression and augmented PA oxidation. CPT-1 inhibitor etomoxir or CPT-1 knockdown augmented PA-induced cell death and reduced T0901317-induced protective effects, whereas the peroxisome proliferator-activated receptor (PPAR)-α agonist bezafibrate reduced PA-induced toxicity. In particular, T0901317 reduced the levels of PA-induced endoplasmic reticulum (ER) stress markers, including phospho-eukaryotic initiation factor-2α, phospho-C-Jun N terminal kinase, and CCAAT/enhancer-binding protein homologous protein. In contrast, knockdown of SREBP-1c or glycerol-3-phosphate acyltransferase 1 augmented PA-induced ER stress responses. Results of these experiments suggested that stimulation of lipid metabolism, including lipogenesis and fatty acid oxidation, protected β-cells from PA-induced lipotoxicity and that protection through enhanced lipogenesis was likely due to reduced ER stress.

scholarly journals Ahnak deficiency attenuates high-fat diet-induced fatty liver in mice through FGF21 induction

2021 ◽  
Author(s):  
Yo Na Kim ◽  
Jae Hoon Shin ◽  
Dong Soo Kyeong ◽  
Soo Young Cho ◽  
Mi-Young Kim ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Fatty Liver ◽  
Hepatic Steatosis ◽  
Fatty Acid Oxidation ◽  
High Fat Diet ◽  
Fibroblast Growth Factor 21 ◽  
Acid Oxidation ◽  
Chow Diet ◽  
High Fat

AbstractThe AHNAK nucleoprotein has been determined to exert an anti-obesity effect in adipose tissue and further inhibit adipogenic differentiation. In this study, we examined the role of AHNAK in regulating hepatic lipid metabolism to prevent diet-induced fatty liver. Ahnak KO mice have reportedly exhibited reduced fat accumulation in the liver and decreased serum triglyceride (TG) levels when provided with either a normal chow diet or a high-fat diet (HFD). Gene expression profiling was used to identify novel factors that could be modulated by genetic manipulation of the Ahnak gene. The results revealed that fibroblast growth factor 21 (FGF21) was markedly increased in the livers of Ahnak KO mice compared with WT mice fed a HFD. Ahnak knockdown in hepatocytes reportedly prevented excessive lipid accumulation induced by palmitate treatment and was associated with increased secretion of FGF21 and the expression of genes involved in fatty acid oxidation, which are primarily downstream of PPARα. These results indicate that pronounced obesity and hepatic steatosis are attenuated in HFD-fed Ahnak KO mice. This may be attributed, in part, to the induction of FGF21 and regulation of lipid metabolism, which are considered to be involved in increased fatty acid oxidation and reduced lipogenesis in the liver. These findings suggest that targeting AHNAK may have beneficial implications in preventing or treating hepatic steatosis.

scholarly journals PPARα-Deficient ob/ob Obese Mice Become More Obese and Manifest Severe Hepatic Steatosis Due to Decreased Fatty Acid Oxidation

2015 ◽  
Vol 185 (5) ◽  
pp. 1396-1408 ◽  
Author(s):  
Qian Gao ◽  
Yuzhi Jia ◽  
Gongshe Yang ◽  
Xiaohong Zhang ◽  
Prajwal C. Boddu ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Hepatic Steatosis ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Obese Mice
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