scholarly journals Differential Lipotoxic Effects of Palmitate and Oleate in Activated Human Hepatic Stellate Cells and Epithelial Hepatoma Cells

2016 ◽  
Vol 39 (4) ◽  
pp. 1648-1662 ◽  
Author(s):  
Alexandra M. Hetherington ◽  
Cynthia G. Sawyez ◽  
Emma Zilberman ◽  
Alexandra M. Stoianov ◽  
Debra L. Robson ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Er Stress ◽  
Hepatic Stellate Cells ◽  
Hepg2 Cells ◽  
Stellate Cells ◽  
Hepatoma Cells ◽  
Surrounding Tissue ◽  
High Oleate ◽  
Activated Hepatic Stellate Cells

Background/Aims: Nonalcoholic fatty liver disease (NAFLD) progression to fibrosis, cirrhosis and hepatocellular carcinoma, alters the cellular composition of this organ. During late-stage NAFLD, fibrotic and possibly cancerous cells can proliferate and, like normal hepatocytes, are exposed to high concentrations of fatty acids from both surrounding tissue and circulating lipid sources. We hypothesized that primary human activated hepatic stellate cells and epithelial hepatoma (HepG2) cells respond differently to lipotoxic conditions, and investigated the mechanisms involved. Methods: Primary activated hepatic stellate cells and HepG2 cells were exposed to pathophysiological concentrations of fatty acids and comparative studies of lipid metabolic and stress response pathways were performed. Results: Both cell types remained proliferative during exposure to a combination of palmitate plus oleate reflective of the general saturated versus unsaturated fatty acid composition of western diets. However, exposure to either high palmitate or high oleate alone induced cytotoxicity in activated stellate cells, while only palmitate caused cytotoxicity in HepG2 cells. mRNA microarray and biochemical comparisons revealed that stellate cells stored markedly less fatty acids as neutral lipids, and had reduced capacity for beta-oxidation. Similar to previous observations in HepG2 cells, palmitate, but not oleate, induced ER stress and actin stress fiber formation in activated stellate cells. In contrast, oleate, but not palmitate, induced the inflammatory signal TXNIP, decreased cytoskeleton proteins, and decreased cell polarity preceding cell death in activated stellate cells. Conclusions: Palmitate-induced lipotoxicity was associated with ER stress pathways in both primary activated hepatic stellate cells and epithelial hepatoma cells, whereas high oleate caused lipotoxicity only in activated stellate cells, possibly through a distinct mechanism involving disruption of cytoskeleton components. This may have implications for optimal dietary fatty acid compositions during various stages of NAFLD.

scholarly journals Differential Effects of Lipid and Vitamin D treatment on Cell Viability and CYP24A1 Expression in Hepatocytes and Hepatic Stellate Cells

2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Zixuan Zhang ◽  
James L. Thorne ◽  
J. Bernadette Moore
Keyword(s):  
Vitamin D ◽  
Fatty Acid ◽  
Cell Viability ◽  
Cell Lines ◽  
Hepatic Stellate Cells ◽  
Hepg2 Cells ◽  
Acid Treatment ◽  
Stellate Cells ◽  
Intracellular Lipid ◽  
Fatty Acid Treatment

AbstractActivated hepatic stellate cells (HSCs) are a key contributor to liver fibrosis and drive the progression to advanced disease for many liver conditions, including non-alcoholic fatty liver disease. Previous studies suggest vitamin D may reduce inflammatory and pro-fibrogenic activity of HSCs in vitro. However, the mechanisms underpinning the effects of vitamin D in HSCs are not fully understood. The overall aim of these experiments was to mimic a lipid loading model on immortalised HSCs to test their responses to 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3). Two different human immortalised cell lines: HepG2, hepatocellular carcinoma cells, and LX-2, hepatic stellate cells; were cultured using standard methods. Cell viability in different treatment vehicles (2% DMSO and/or 0.1% ethanol) under serum free conditions was measured by MTT assay after 6 and 24 h. Cells were cultured with increasing concentrations of fatty acids (0–500μM, 1:1 oleic acid: palmitic acid) or vitamin D. Nile red, a neutral lipophilic fluorescent dye, was used to measure total intracellular lipid and quantified relative to vehicle. CYP24A1 mRNA expression was measured by qPCR in response to 1000nM 1α,25(OH)2D3 treatment in both cell lines for 24 h using TaqMan® gene expression assays and normalised to 18S rRNA. Cell viability in response to vehicle was examined at 6 h and 24 h to determine the optimal experimental time points. Whereas, HepG2 cells remained unaffected at 24 h in response to either or both vehicles combined (n = 4; combined vehicles, P = 0.3187), LX-2 cells showed reduced viability even at 6 h (n = 5; combined vehicles, P = 0.0050). Fatty acid treatment led to intracellular lipid accumulation in both cell lines. In response to 500μM fatty acid treatment, intracellular lipid increased by 1.7-fold in LX-2 cells at 6 h (n = 5, P = 0.00174) and 3.9-fold in HepG2 cells after 24 h (n = 4, P = 0.00184). Notably, CYP24A1 mRNA expression was markedly induced by vitamin D treatment in LX-2 cells (136 ± 7.64-fold, n = 3, P = 0.0010) in comparison to HepG2 cells (22 ± 0.78-fold, n = 3, P < 0.0001). In summary, the cell viability data suggested optimal time points for both fatty acid and vitamin D treatments may be 6 h for LX-2 cells, and 24 h for HepG2 cells. While intracellular lipid accumulation differed between the cell lines in response to fatty acid treatment, both cell lines produced a dose-dependent increase in intracellular lipid. Lastly, CYP24A1 mRNA expression confirmed the responsiveness of both cell types to vitamin D treatment. Ongoing experiments are examining microRNA expression in HSCs in response to both vitamin D and lipid loading.

Synergistic effect of natural compounds on the fatty acid-induced autophagy of activated hepatic stellate cells

2014 ◽  
Vol 25 (9) ◽  
pp. 903-913 ◽  
Author(s):  
Kuan-Wei Lee ◽  
Varadharajan Thiyagarajan ◽  
Huei-Wun Sie ◽  
Ming-Fan Cheng ◽  
May-Jywan Tsai ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Synergistic Effect ◽  
Hepatic Stellate Cells ◽  
Stellate Cells ◽  
Natural Compounds ◽  
Activated Hepatic Stellate Cells

scholarly journals Determination of the Underlying Mechanisms for the Anti-fibrogenic Effect of n-3 Polyunsaturated Fatty Acids in Hepatic Stellate Cells (P08-105-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Siqi Hu ◽  
Minkyung Bae ◽  
Young-Ki Park ◽  
Ji-Young Lee
Keyword(s):  
Gene Expression ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Hepatic Stellate Cells ◽  
Stellate Cells ◽  
Inhibitory Effect ◽  
Basal Expression ◽  
Epa And Dha ◽  
Human Hscs ◽  
Underlying Mechanisms

Abstract Objectives We previously reported that n-3 polyunsaturated fatty acids (PUFAs) exhibit potent anti-fibrogenic effects independent of the SMA- and MAD-related protein (SMAD3) pathway in primary human hepatic stellate cells (HSCs), the major cell type responsible for extracellular matrix production for the development of liver fibrosis. The objective of this study was to further elucidate the underlying mechanisms for the anti-fibrogenic effect of n-3 PUFAs in HSCs with a primary focus on peroxisome proliferator-activated receptor γ (PPARγ) as it is known to inhibit HSC activation. Methods n-3 PUFAs, including alpha linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were complexed with bovine serum albumin (BSA) at a BSA to fatty acid molar ratio of 1:2.5. Primary human HSCs were treated either with BSA vehicle control or 50 μM of a fatty acid for 24 h, after which they were activated with transforming growth factor β1 (TGFβ1; 4 ng/ml), a potent fibrogenic cytokine, for additional 24 h. Also, in another experiment, primary human HSCs were pre-treated with 10 μM of GW9662, a PPARγ antagonist, 18 h prior to the fatty acid and TGFβ1 treatments. Results ALA, EPA and DHA significantly decreased TGFβ1-induced mRNA expression of fibrogenic genes such as α-smooth muscle actin and collagen type I alpha 1 chain with EPA and DHA being more potent than ALA. The similar trend was also observed in their protein levels. In the absence of TGFβ1 treatment, EPA and DHA markedly increased PPARγ mRNA abundance. TGFβ1 significantly decreased PPARγ mRNA, which was attenuated by EPA and DHA, but not by ALA. Inhibition of PPARγ by GW9662 did not alter either the basal expression of PPARγ or the basal expression of fibrogenic genes. However, the inhibitory effect of EPA and DHA on the induction of fibrogenic gene expression by TGFβ1 was not diminished by GW9662. Conclusions n-3 PUFAs showed a potent inhibitory effect on TGFβ1-induced fibrogenic gene expression in primary human HSCs. Inhibition of PPARγ activity did not alter the anti-fibrogenic effect of n-3 PUFAs. The results suggest that n-3 PUFAs, particularly EPA and DHA to a similar degree, exert their anti-fibrogenic effect in primary human HSCs independent of the activation of PPARγ pathway. Funding Sources This study was supported by USDA Multistate Hatch and USDA Hatch.

HCV/TLR3 modulated the expression of RANTES in murine activated hepatic stellate cells

2012 ◽  
Vol 50 (01) ◽  
Author(s):  
B Wang ◽  
R Bröring ◽  
CI Real ◽  
M Trippler ◽  
G Gerken ◽  
...  
Keyword(s):  
Hepatic Stellate Cells ◽  
Stellate Cells ◽  
Activated Hepatic Stellate Cells
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