scholarly journals Perturbation of TM6SF2 Expression Alters Lipid Metabolism in a Human Liver Cell Line

2021 ◽  
Vol 22 (18) ◽  
pp. 9758
Author(s):  
Asmita Pant ◽  
Yue Chen ◽  
Annapurna Kuppa ◽  
Xiaomeng Du ◽  
Brian D. Halligan ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Lipid Accumulation ◽  
Fluorescent Imaging ◽  
Genome Wide Association Studies ◽  
Loss Of Function ◽  
Wild Type ◽  
Hepatic Lipid Metabolism ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipid ◽  
Human Liver Cell

Non-alcoholic fatty liver disease (NAFLD) is caused by excess lipid accumulation in hepatocytes. Genome-wide association studies have identified a strong association of NAFLD with non-synonymous E167K amino acid mutation in the transmembrane 6 superfamily member 2 (TM6SF2) protein. The E167K mutation reduces TM6SF2 stability, and its carriers display increased hepatic lipids and lower serum triglycerides. However, the effects of TM6SF2 on hepatic lipid metabolism are not completely understood. We overexpressed wild-type or E167K variant of TM6SF2 or knocked down TM6SF2 expression in lipid-treated Huh-7 cells and used untargeted lipidomic analysis, RNAseq transcriptome analysis, and fluorescent imaging to determine changes in hepatic lipid metabolism. Both TM6SF2 knockdown and E167K overexpression increased hepatic lipid accumulation, while wild-type overexpression decreased acylglyceride levels. We also observed lipid chain remodeling for acylglycerides by TM6SF2 knockdown, leading to a relative increase in species with shorter, more saturated side chains. RNA-sequencing revealed differential expression of several lipid metabolizing genes, including genes belonging to AKR1 family and lipases, primarily in cells with TM6SF2 knockdown. Taken together, our data show that overexpression of TM6SF2 gene or its loss-of-function changes hepatic lipid species composition and expression of lipid metabolizing genes. Additionally, our data further confirms a loss-of-function effect for the E167K variant.

scholarly journals Perturbation of transmembrane 6 superfamily member 2 expression alters lipid metabolism in a human liver cell line

2021 ◽  
Author(s):  
Asmita Pant ◽  
Yue Chen ◽  
Annapurna Kuppa ◽  
Xiaomeng Du ◽  
Brian Halligan ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Lipid Droplets ◽  
Association Studies ◽  
Fluorescent Imaging ◽  
Genome Wide Association Studies ◽  
Loss Of Function ◽  
Wild Type ◽  
Hepatic Lipid ◽  
Lipid Species ◽  
Human Liver Cell

Background: Nonalcoholic fatty liver disease (NAFLD) is caused by accumulation of excess lipids in hepatocytes. Genome wide association studies have identified strong association of NAFLD with non-synonymous E167K amino acid mutation in transmembrane 6 superfamily member 2 (TM6SF2) protein. The E167K mutation affects TM6SF2 stability and its carriers display increased hepatic lipids levels and lower serum triglycerides. While similar phenotype is evident in mice with TM6SF2 knockdown, effects of TM6SF2 on hepatic lipid metabolism is not completely understood. Methods: Here, we overexpressed wild-type or E167K variant of TM6SF2 or knocked down TM6SF2 expression in lipid-treated Huh-7 cells and used biochemical assays, untargeted lipidomic analysis, RNAseq transcriptome analysis and high-throughput fluorescent imaging to determine changes in lipid metabolism. Results: Both knockdown and E167K overexpression increased acylglyceride levels which was decreased by wild-type TM6SF2 overexpression. Further, mean intensity of individual lipid droplets was increased by E167K overexpression and knockdown while wild-type TM6SF2 had no effects. We also observed lipid chain remodeling for acylglycerides by TM6SF2 knockdown leading to a relative increase in species with shorter and more saturated side chains. RNA sequencing revealed differential expression of several lipid metabolizing genes, including genes belonging to AKR1 family and lipases, primarily in cells with TM6SF2 knockdown. Conclusion: Taken together, our data shows that overexpression of TM6SF2 gene or its loss-of-function changes hepatic lipid species composition and expression of lipid metabolizing genes. Further, overexpression of E167K variant and TM6SF2 knockdown similarly increased hepatic lipid accumulation and lipid droplets profile further confirming a loss-of-function effect for variant.

scholarly journals Hepatic MIR20B promotes nonalcoholic fatty liver disease by suppressing PPARA

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Yo Han Lee ◽  
Hyun-Jun Jang ◽  
Sounkou Kim ◽  
Sun Sil Choi ◽  
Keon Woo Khim ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Liver Disease ◽  
Network Analysis ◽  
Fatty Liver ◽  
Lipid Accumulation ◽  
Fatty Liver Disease ◽  
Synergic Effect ◽  
Hepatic Lipid Metabolism ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipid

Background:Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation and imbalances in lipid metabolism in the liver. Although nuclear receptors (NRs) play a crucial role in hepatic lipid metabolism, the underlying mechanisms of NR regulation in NAFLD remain largely unclear. Methods:Using network analysis and RNA-seq to determine the correlation between NRs and microRNA in human NAFLD patients, we revealed that MIR20B specifically targets PPARA. MIR20B mimic and anti-MIR20B were administered to human HepG2 and Huh-7 cells and mouse primary hepatocytes as well as high fat diet (HFD)- or methionine-deficient diet (MCD)-fed mice to verify the specific function of MIR20B in NAFLD. We tested the inhibition of the therapeutic effect of a PPARα agonist, fenofibrate, by Mir20b and the synergic effect of combination of fenofibrate with anti-Mir20b in NAFLD mouse model. Results:We revealed that MIR20B specifically targets PPARA through miRNA regulatory network analysis of nuclear receptor genes in NAFLD. The expression of MIR20B was upregulated in free fatty acid (FA)-treated hepatocytes and the livers of both obesity-induced mice and NAFLD patients. Overexpression of MIR20B significantly increased hepatic lipid accumulation and triglyceride levels. Furthermore, MIR20B significantly reduced FA oxidation and mitochondrial biogenesis by targeting PPARA. In Mir20b-introduced mice, the effect of fenofibrate to ameliorate hepatic steatosis was significantly suppressed. Finally, inhibition of Mir20b significantly increased FA oxidation and uptake, resulting in improved insulin sensitivity and a decrease in NAFLD progression. Moreover, combination of fenofibrate and anti-Mir20b exhibited the synergic effect on improvement of NAFLD in MCD-fed mice. Conclusions:Taken together, our results demonstrate that the novel MIR20B targets PPARA, plays a significant role in hepatic lipid metabolism, and present an opportunity for the development of novel therapeutics for NAFLD. Funding:This research was funded by Korea Mouse Phenotyping Project (2016M3A9D5A01952411), the National Research Foundation of Korea (NRF) grant funded by the Korea government (2020R1F1A1061267, 2018R1A5A1024340, NRF-2021R1I1A2041463, 2020R1I1A1A01074940), and the Future-leading Project Research Fund (1.210034.01) of UNIST.

scholarly journals Tribbles-1: a novel regulator of hepatic lipid metabolism in humans

2015 ◽  
Vol 43 (5) ◽  
pp. 1079-1084 ◽  
Author(s):  
Robert C. Bauer ◽  
Batuhan O. Yenilmez ◽  
Daniel J. Rader
Keyword(s):  
Lipid Metabolism ◽  
Plasma Lipids ◽  
Association Studies ◽  
Plasma Lipid ◽  
Genome Wide Association Studies ◽  
Dependent Manner ◽  
Hepatic Lipogenesis ◽  
Hepatic Lipid Metabolism ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipid

The protein tribbles-1, encoded by the gene TRIB1, is increasingly recognized as a major regulator of multiple cellular and physiological processes in humans. Recent human genetic studies, as well as molecular biological approaches, have implicated this intriguing protein in the aetiology of multiple human diseases, including myeloid leukaemia, Crohn's disease, non-alcoholic fatty liver disease (NAFLD), dyslipidaemia and coronary artery disease (CAD). Genome-wide association studies (GWAS) have repeatedly identified variants at the genomic TRIB1 locus as being significantly associated with multiple plasma lipid traits and cardiovascular disease (CVD) in humans. The involvement of TRIB1 in hepatic lipid metabolism has been validated through viral-mediated hepatic overexpression of the gene in mice; increasing levels of TRIB1 decreased plasma lipids in a dose-dependent manner. Additional studies have implicated TRIB1 in the regulation of hepatic lipogenesis and NAFLD. The exact mechanisms of TRIB1 regulation of both plasma lipids and hepatic lipogenesis remain undetermined, although multiple signalling pathways and transcription factors have been implicated in tribbles-1 function. Recent reports have been aimed at developing TRIB1-based lipid therapeutics. In summary, tribbles-1 is an important modulator of human energy metabolism and metabolic syndromes and worthy of future studies aimed at investigating its potential as a therapeutic target.

Effect of specific amino acids on hepatic lipid metabolism in fructose-induced non-alcoholic fatty liver disease

2016 ◽  
Vol 35 (1) ◽  
pp. 175-182 ◽  
Author(s):  
Prasanthi Jegatheesan ◽  
Stéphanie Beutheu ◽  
Gabrielle Ventura ◽  
Gilles Sarfati ◽  
Esther Nubret ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lipid Metabolism ◽  
Liver Disease ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Hepatic Lipid Metabolism ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipid ◽  
Alcoholic Fatty Liver Disease

scholarly journals Hepatic miR-20b promotes nonalcoholic fatty liver disease by suppressing PPARα

2021 ◽  
Author(s):  
Yo Han Lee ◽  
Hyun-Jun Jang ◽  
Sounkou Kim ◽  
Sun Sil Choi ◽  
Keon Woo Khim ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Liver Disease ◽  
Network Analysis ◽  
Fatty Liver ◽  
Lipid Accumulation ◽  
Fatty Liver Disease ◽  
Metabolic Reprogramming ◽  
Deficient Diet ◽  
Alcoholic Fatty Liver ◽  
Hepatic Lipid

Background: Non-alcoholic fatty liver disease (NAFLD) is associated with hepatic metabolic reprogramming that leads to excessive lipid accumulation and imbalances in lipid metabolism in the liver. Although nuclear receptors (NRs) play a crucial role in hepatic metabolic reprogramming, the underlying mechanisms of NR regulation in NAFLD remain largely unclear. Methods: Using network analysis and RNA-seq to determine the correlation between NRs and microRNA in NAFLD patients, we revealed that miR-20b specifically targets PPARα. miR-20b mimic and anti-miR-20b were administered to hepatocytes as well as high fat diet (HFD)- or methionine-deficient diet (MCD)-fed mice to verify the specific function of miR-20b in NAFLD. We tested the inhibition of the therapeutic effect of a PPARα agonist, fenofibrate, by miR-20b. Results: We revealed that miR-20b specifically targets PPARα through miRNA regulatory network analysis of nuclear receptor genes in NAFLD. The expression of miR-20b was upregulated in free fatty acid (FA)-treated hepatocytes and the livers of both obesity-induced mice and NAFLD patients. Overexpression of miR-20b significantly increased hepatic lipid accumulation and triglyceride levels. Furthermore, miR-20b significantly reduced FA oxidation and mitochondrial biogenesis by targeting PPARα. In miR-20b-introduced mice, the effect of fenofibrate to ameliorate hepatic steatosis was significantly suppressed. Finally, inhibition of miR-20b significantly increased FA oxidation and uptake, resulting in improved insulin sensitivity and a decrease in NAFLD progression. Conclusions: Taken together, our results demonstrate that the novel miR-20b targets PPARα, plays a significant role in hepatic lipid metabolism, and present an opportunity for the development of novel therapeutics for NAFLD. Funding: This research was funded by Korea Mouse Phenotyping Project (2016M3A9D5A01952411), the National Research Foundation of Korea (NRF) grant funded by the Korea government (2020R1F1A1061267, 2018R1A5A1024340), the Future-leading Project Research Fund (1.210034.01) of UNIST and the National Research Foundation of Korea (NRF) grant funded by the Korea government (2020R1I1A1A01074940).

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