scholarly journals Molecular mechanism of intracellular lipid accumulation: Suppressive effect of PycnogenolR in liver cells

2013 ◽  
Vol 3 (9) ◽  
pp. 353 ◽  
Author(s):  
Shoichiro Ikuyama ◽  
Bin Fan ◽  
Jian-Qiu Gu ◽  
Kumiko Mukae ◽  
Hideyuki Watanabe
Keyword(s):  
Oleic Acid ◽  
Fatty Liver ◽  
Lipid Accumulation ◽  
Promoter Activity ◽  
Pathological Condition ◽  
Suppressive Effect ◽  
Liver Cells ◽  
Intracellular Lipid ◽  
Target Molecule ◽  
Intracellular Lipid Accumulation

Cells are physiologically ready to accumulate lipids such as triacylglycerides in the cytoplasm. Five classes of perilipin (PLIN) family proteins are known to be involved in the process of intracellular lipid accumulation. PLIN2 is expressed ubiquitously including adipocytes, hepatocytes and macrophages. Over-expression of PLIN2 is demonstrated in the lesions of fatty liver diseases and atherosclerosis. Suppression of PLIN2 expression prevents from developing these pathological conditions in animal models, suggesting that PLIN2 could be a therapeutic target molecule for excessive intracellular lipid accumulation which leads to various metabolic derangements. The PLIN2 gene promoter has two important cis-acting elements in close proximity:AP-1 element which mediates inflammatory signals and PPRE which mediates free fatty acid effect. In NMuLi mouse liver cells, FFA such as oleic acid requires both functional AP-1 and PPRE simultaneously to stimulate the promoter activity, indicating the presence of intimate interaction of inflammatory and metabolic signals on this gene. PycnogenolR, French maritime pine bark extracts, suppressed the oleic acid-induced PLIN2 expression and lipid accumulation in NMuLi cells. We found that PycnogenolR did not suppress the PLIN2 promoter activity or AP-1 binding to DNA. Instead, PycnogenolR facilitates the PLIN2 mRNA degradation, leading to suppression of lipid accumulation. This effect seems to be independent of antioxidant effect of PycnogenolR. We raise the idea that PLIN2 is a putative target molecule for prevention of pathological condition induced by excessive lipid accumulation, and this class of natural compounds could be putative therapeutic modalities.Key words: PycnogenolR, lipid droplet, perilipin, fatty liver disease

scholarly journals Zanthoxylum ailanthoides Suppresses Oleic Acid-Induced Lipid Accumulation through an Activation of LKB1/AMPK Pathway in HepG2 Cells

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Eun-Bin Kwon ◽  
Myung-Ji Kang ◽  
Soo-Yeon Kim ◽  
Yong-Moon Lee ◽  
Mi-Kyeong Lee ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Lipid Accumulation ◽  
Hepg2 Cells ◽  
Methanol Extract ◽  
De Novo ◽  
Oxygen Species ◽  
Gene Expressions ◽  
Intracellular Lipid ◽  
Ampk Signaling ◽  
Intracellular Lipid Accumulation

Zanthoxylum ailanthoides (ZA) has been used as folk medicines in East Asian and recently reported to have several bioactivity; however, the studies of ZA on the regulation of triacylglycerol (TG) biosynthesis have not been elucidated yet. In this study, we examined whether the methanol extract of ZA (ZA-M) could reduce oleic acid- (OA-) induced intracellular lipid accumulation and confirmed its mode of action in HepG2 cells. ZA-M was shown to promote the phosphorylation of AMPK and its upstream LKB1, followed by reduction of lipogenic gene expressions. As a result, treatment of ZA-M blocked de novo TG biosynthesis and subsequently mitigated intracellular neutral lipid accumulation in HepG2 cells. ZA-M also inhibited OA-induced production of reactive oxygen species (ROS) and TNF-α, suggesting that ZA-M possess the anti-inflammatory feature in fatty acid over accumulated condition. Taken together, these results suggest that ZA-M attenuates OA-induced lipid accumulation and inflammation through the activation of LKB1/AMPK signaling pathway in HepG2 cells.

Oleic acid-induced ADRP expression requires both AP-1 and PPAR response elements, and is reduced by Pycnogenol through mRNA degradation in NMuLi liver cells

2009 ◽  
Vol 297 (1) ◽  
pp. E112-E123 ◽  
Author(s):  
Bin Fan ◽  
Shoichiro Ikuyama ◽  
Jian-Qiu Gu ◽  
Ping Wei ◽  
Jun-ichi Oyama ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Dna Binding ◽  
Lipid Accumulation ◽  
Promoter Activity ◽  
Mrna Degradation ◽  
Liver Cells ◽  
Bark Extract ◽  
Peroxisome Proliferator ◽  
Acid Effect ◽  
Peroxisome Proliferator Activated Receptors

Fatty acids stimulate lipid accumulation in parallel with increased expression of adipose differentiation-related protein (ADRP) in liver cells. Although it is generally considered that the fatty acid effect on ADRP expression is mediated by peroxisome proliferator-activated receptors (PPARs), we identified here an additional molecular mechanism using the NMuLi mouse liver nonparenchymal cell line, which expresses PPARγ and δ but not α. Oleic acid (OA) and specific ligands for PPARγ and -δ stimulated ADRP expression as well as the −2,090-bp ADRP promoter activity which encompasses the PPAR response element (PPRE) adjacent to an Ets/activator protein (AP)-1 site. When the AP-1 site was mutated, OA failed to stimulate the activity despite the presence of the PPRE, whereas ligands for PPARγ and -δ did stimulate it and so did a PPARα ligand under the coexpression of PPARα. DNA binding of AP-1 was stimulated by OA but not by PPAR ligands. Because we previously demonstrated that Pycnogenol (PYC), a French maritime pine bark extract, suppressed ADRP expression in macrophages partly by suppression of AP-1 activity, we tested the effect of PYC on NMuLi cells. PYC reduced the OA-induced ADRP expression along with suppression of lipid droplet formation. However, PYC neither suppressed the OA-stimulated ADRP promoter activity nor DNA binding of AP-1 but, instead, reduced the ADRP mRNA half-life. All these results indicate that the effect of OA on ADRP expression requires AP-1 as well as PPRE, and PYC suppresses the ADRP expression in part by facilitating mRNA degradation. PYC, a widely used dietary supplement, could be beneficial for the prevention of excessive lipid accumulation such as hepatic steatosis.

scholarly journals Diosgenin ameliorates palmitic acid-induced lipid accumulation via AMPK/ACC/CPT-1A and SREBP-1c/FAS signaling pathways in LO2 cells

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Ke Fang ◽  
Fan Wu ◽  
Guang Chen ◽  
Hui Dong ◽  
Jingbin Li ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Fatty Acid ◽  
Liver Disease ◽  
Fatty Liver ◽  
Palmitic Acid ◽  
Mitochondrial Function ◽  
Lipid Accumulation ◽  
Lipid Synthesis ◽  
Underlying Mechanism ◽  
Intracellular Lipid

Abstract Background Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and is characterized by excessive hepatic lipid accumulation. Many studies have suggested that lipid overload is the key initial factor that contributes to hepatic steatosis. Our previous study indicated that diosgenin (DSG) has a beneficial effect on energy metabolism, but the underlying mechanism remains unclear. Methods Human normal hepatocytes (LO2 cells) were incubated with palmitic acid to establish the cell model of nonalcoholic fatty liver. The effects of DSG on lipid metabolism, glucose uptake and mitochondrial function were evaluated. Furthermore, the mechanism of DSG on oxidative stress, lipid consumption and lipid synthesis in LO2 cells was investigated. Results The results indicated that palmitic acid induced obvious lipid accumulation in LO2 cells and that DSG treatment significantly reduced the intracellular lipid content. DSG treatment upregulated expression of lipolysis proteins, including phospho-AMP activated protein kinase (p-AMPK), phospho-acetyl-coA carboxylase (p-ACC) and carnitine acyl transferase 1A (CPT-1A), and inhibited expression of lipid synthesis-related proteins, including sterol regulatory element-binding protein 1c (SREBP-1c) and fatty acid synthase (FAS). Additionally, DSG-treated cells displayed a marked improvement in mitochondrial function, with less production of reactive oxygen species and a higher mitochondrial membrane potential compared with the model group. Conclusion This study suggests that DSG can reduce intracellular lipid accumulation in LO2 cells and that the underlying mechanism may be related to the improving oxidative stress, increasing fatty acid β-oxidation and decreasing lipid synthesis. The above changes might be mediated by the activation of the AMPK/ACC/CPT-1A pathway and inhibition of the SREBP-1c/FAS pathway.

scholarly journals Association of intracellular lipid accumulation in subcutaneous adipocyte precursors and plasma adipokines in bariatric surgery candidates

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Ioana Hristov ◽  
Veronica Mocanu ◽  
Florin Zugun-Eloae ◽  
Luminita Labusca ◽  
Iustina Cretu-Silivestru ◽  
...  
Keyword(s):  
Bariatric Surgery ◽  
Lipid Accumulation ◽  
Intracellular Lipid ◽  
Intracellular Lipid Accumulation

Dysregulation of low-density lipoprotein receptor contributes to podocyte injuries in diabetic nephropathy

2015 ◽  
Vol 308 (12) ◽  
pp. E1140-E1148 ◽  
Author(s):  
Yang Zhang ◽  
Kun Ling Ma ◽  
Jing Liu ◽  
Yu Wu ◽  
Ze Bo Hu ◽  
...  
Keyword(s):  
High Glucose ◽  
Lipid Accumulation ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Lipoprotein Receptor ◽  
Intracellular Lipid ◽  
Phenotypic Alteration ◽  
Density Lipoprotein Receptor ◽  
Intracellular Lipid Accumulation

Dyslipidemia plays crucial roles in the progression of diabetic nephropathy (DN). This study investigated the effects of high glucose on lipid accumulation in podocytes and explored its underlying mechanisms. Male db/m and db/db mice were fed a normal chow diet for 8 wk. Immortalised mouse podocytes were treated with or without high glucose for 24 h. The changes to the morphology and ultramicrostructures of the kidneys in mice were examined using pathological staining and electron microscopy. Intracellular lipid accumulation was evaluated by Oil Red O staining and a free cholesterol quantitative assay. The expressions of the molecules involved in low-density lipoprotein receptor (LDLr) pathway and podocyte injury were examined using immunofluorescent staining, real-time PCR, and Western blot. There were increased levels of plasma lipid, serum creatinine, and proteinuria in db/db mice compared with db/m mice. Moreover, there was significant mesangial matrix expansion, basement membrane thickening, podocyte foot process effacement, and phenotypic alteration in the db/db group. Additionally, lipid accumulation in the kidneys of db/db mice was increased due to increased protein expressions of LDLr, sterol regulatory element-binding protein (SREBP) cleavage-activating protein, and SREBP-2. These effects were further confirmed by in vitro studies. Interestingly, the treatment with LDLr siRNA inhibited lipid accumulation in podocytes and decreased the protein expression of molecules associated with phenotypic alteration in podocytes. High glucose disrupted LDLr feedback regulation in podocytes, which may cause intracellular lipid accumulation and alteration of podocyte phenotype, thereby accelerating DN progression.

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