scholarly journals Human MicroRNA-548p Decreases Hepatic Apolipoprotein B Secretion and Lipid Synthesis

2017 ◽  
Vol 37 (5) ◽  
pp. 786-793 ◽  
Author(s):  
Liye Zhou ◽  
M. Mahmood Hussain
Keyword(s):  
Fatty Acid ◽  
Apolipoprotein B ◽  
Untranslated Region ◽  
Lipid Synthesis ◽  
Site Directed Mutagenesis ◽  
Acid Oxidation ◽  
Human Hepatoma ◽  
Human Hepatoma Cells ◽  
Apob Mrna ◽  
Apob Secretion

Objective— MicroRNAs (miRs) play important regulatory roles in lipid metabolism. Apolipoprotein B (ApoB), as the only essential scaffolding protein in the assembly of very-low-density lipoproteins, is a target to treat hyperlipidemia and atherosclerosis. We aimed to find out miRs that reduce apoB expression. Approach and Results— Bioinformatic analyses predicted that hsa-miR-548p can interact with apoB mRNA. MiR-548p or control miR was transfected in human and mouse liver cells to test its role in regulating apoB secretion and mRNA expression levels. Site-directed mutagenesis was used to identify the interacting site of miR-548p in human apoB 3′-untranslated region. Fatty acid oxidation and lipid syntheses were examined in miR-548p overexpressing cells to investigate its function in lipid metabolism. We observed that miR-548p significantly reduces apoB secretion from human hepatoma cells and primary hepatocytes. Mechanistic studies showed that miR-548p interacts with the 3′-untranslated region of human apoB mRNA to enhance post-transcriptional degradation. Bioinformatic algorithms suggested 2 potential binding sites of miR-548p on human apoB mRNA. Site-directed mutagenesis studies revealed that miR-548p targets site I involving both seed and supplementary sequences. MiR-548p had no effect on fatty acid oxidation but significantly decreased lipid synthesis in human hepatoma cells by reducing HMGCR (3-hydroxy-3-methylglutaryl-coenzyme A reductase) and ACSL4 (Acyl-CoA synthetase long-chain family member 4) enzymes involved in cholesterol and fatty acid synthesis. In summary, miR-548p reduces lipoprotein production and lipid synthesis by reducing expression of different genes in human liver cells. Conclusions— These studies suggest that miR-548p regulates apoB secretion by targeting mRNA. It is likely that it could be useful in treating atherosclerosis, hyperlipidemia, and hepatosteatosis.

Abstract 573: Human Microrna-548p Decreases apoB Secretion and Lipid Synthesis

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Liye Zhou ◽  
Mahmood Hussain
Keyword(s):  
Fatty Acid ◽  
Untranslated Region ◽  
Lipid Synthesis ◽  
Hepatoma Cells ◽  
Site Directed Mutagenesis ◽  
Acid Oxidation ◽  
Human Hepatoma ◽  
Human Hepatoma Cells ◽  
Apob Mrna ◽  
Apob Secretion

Objective: MicroRNAs (miRs) play important regulatory roles in lipid and lipoprotein metabolism. ApoB, as the only essential scaffolding protein in the assembly of very low density lipoproteins, is a target to treat hyperlipidemia and atherosclerosis. We aimed to find out miRs that reduce apoB expression. Approach: Bioinformatics analyses predicted that hsa-miR-548p can interact with apoB mRNA.MiR-548p mimic and control were transfected in human and mouse hepatoma cell lines to test its role in regulating apoB secretion and mRNA expression levels. Site-directed mutagenesis was used to identify the interacting site of miR-548p in human apoB 3′-untranslated region. Fatty acid oxidation and lipid syntheses were examined in miR-548p overexpressing cells to investigate its function in lipid metabolism. Results: Experimentally, we observed that miR-548p significantly reduces apoB secretion from human hepatoma cells in time and dose dependent manner. Mechanistic studies showed that miR-548p interacts with the 3′-untranslated region of human apoB mRNA to enhance posttranscriptional degradation. Bioinformatics algorithms suggested two potential binding sites of miR-548p on human apoB mRNA. Site-directed mutagenesis studies revealed that miR-548p targets site II involving both seed and supplementary sequences. MiR-548p had no effect on fatty acid oxidation but significantly decreased lipid synthesis in human hepatoma cells by reducing the expression of HMGCR and ACSL4 enzymes involved in cholesterol and fatty acid synthesis. In summary, miR-548p reduces lipoprotein production and lipid synthesis by reducing expression of different genes in human hepatoma cells. Conclusion: These studies suggest that miR-548p could be useful in treating atherosclerosis, hyperlipidemia and hepatosteatosis.

scholarly journals Ethanol and C2 ceramide activate fatty acid oxidation in human hepatoma cells

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Jason M. Correnti ◽  
Lauren Gottshall ◽  
Annie Lin ◽  
Bianca Williams ◽  
Amanke Oranu ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Hepatoma Cells ◽  
Acid Oxidation ◽  
Human Hepatoma ◽  
Human Hepatoma Cells

Effect of aging on lipid composition and metabolism in the adipose tissues of the rat

1961 ◽  
Vol 201 (3) ◽  
pp. 540-546 ◽  
Author(s):  
William Benjamin ◽  
Alfred Gellhorn ◽  
Mary Wagner ◽  
Harold Kundel
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Palmitic Acid ◽  
Subcutaneous Fat ◽  
Lipid Synthesis ◽  
Pentose Phosphate ◽  
Acid Oxidation ◽  
Acetate Incorporation ◽  
Adipose Tissues

Lipid metabolism and chemistry was studied in adipose tissues of the rat from the age of 38 days to 647 days. Aging process was characterized by a marked decrease in lipid synthesis from acetate, a reduction in the proportion of glucose metabolized by the pentose phosphate pathway, and a lower rate of palmitate incorporation into the mixed lipids. Oxidation of palmitic acid to CO2 and release of free fatty acid by epididymal fat was the same in young and old tissues under control conditions; when, however, glucose was absent from the medium or when epinephrine was added, there was a significantly greater rate of palmitic acid oxidation and free fatty acid release by young compared to old adipose tissue. Rate of acetate incorporation into mixed lipids by multiple adipose tissue sites was determined at different ages. Consistently greater rates of lipid biosynthesis were found in the epididymal, perirenal, mesenteric and interscapular adipose tissues than in subcutaneous fat at all ages. Rate of lipid synthesis by the interscapular fat (unlike any of the other depots) remained high at all ages studied. A greater proportion of short chain fatty acids was found in adipose tissues from young rats than in the old. This was related to fatty acid composition of rat milk.

Autoactivation and calpain-1-mediated shedding of hepsin in human hepatoma cells

2019 ◽  
Vol 476 (16) ◽  
pp. 2355-2369 ◽  
Author(s):  
Lina Wang ◽  
Ce Zhang ◽  
Shijin Sun ◽  
Yue Chen ◽  
Yae Hu ◽  
...  
Keyword(s):  
Cancer Metastasis ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Human Hepatoma ◽  
Zymogen Activation ◽  
Cellular Mechanisms ◽  
Human Hepatoma Cells ◽  
Extracellular Region ◽  
Human Hepatoma Hepg2 Cells ◽  
Transmembrane Serine Protease

Abstract Hepsin is a transmembrane serine protease implicated in many biological processes, including hepatocyte growth, urinary protein secretion, auditory nerve development, and cancer metastasis. Zymogen activation is critical for hepsin function. To date, how hepsin is activated and regulated in cells remains an enigma. In this study, we conducted site-directed mutagenesis, cell expression, plasma membrane protein labeling, trypsin digestion, Western blotting, and flow cytometry experiments in human hepatoma HepG2 cells, where hepsin was originally discovered, and SMMC-7721 cells. Our results show that hepsin is activated by autocatalysis on the cell surface but not intracellularly. Moreover, we show that hepsin undergoes ectodomain shedding. In the conditioned medium from HepG2 and SMMC-7721 cells, we detected a soluble fragment comprising nearly the entire extracellular region of hepsin. By testing protease inhibitors, gene knockdown, and site-directed mutagenesis, we identified calpain-1 as a primary protease that acted extracellularly to cleave Tyr52 in the juxtamembrane space of hepsin. These results provide new insights into the biochemical and cellular mechanisms that regulate hepsin expression and activity.

scholarly journals Impact of maternal undernutrition around the time of conception on factors regulating hepatic lipid metabolism and microRNAs in singleton and twin fetuses

2016 ◽  
Vol 310 (2) ◽  
pp. E148-E159 ◽  
Author(s):  
Shervi Lie ◽  
Janna L. Morrison ◽  
Olivia Williams-Wyss ◽  
Catherine M. Suter ◽  
David T. Humphreys ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Lipid Synthesis ◽  
Acid Oxidation ◽  
Protein Abundance ◽  
Hepatic Lipid Metabolism ◽  
Hepatic Lipid ◽  
Maternal Undernutrition ◽  
Hepatic Fatty Acid ◽  
Embryo Number

We have investigated the effects of embryo number and maternal undernutrition imposed either around the time of conception or before implantation on hepatic lipid metabolism in the sheep fetus. We have demonstrated that periconceptional undernutrition and preimplantation undernutrition each resulted in decreased hepatic fatty acid β-oxidation regulators, PGC-1α ( P < 0.05), PDK2 ( P < 0.01), and PDK4 ( P < 0.01) mRNA expression in singleton and twin fetuses at 135–138 days gestation. In singletons, there was also lower hepatic PDK4 ( P < 0.01), CPT-1 ( P < 0.01), and PKCζ ( P < 0.01) protein abundance in the PCUN and PIUN groups and a lower protein abundance of PDPK-1 ( P < 0.05) in the PCUN group. Interestingly, in twins, the hepatic protein abundance of p-AMPK (Ser485) ( P < 0.01), p-PDPK-1 (Ser41) ( P < 0.05), and PKCζ ( P < 0.05) was higher in the PCUN and PIUN groups, and hepatic PDK4 ( P < 0.001) and CPT-1 ( P < 0.05) protein abundance was also higher in the PIUN twin fetus. We also found that the expression of a number of microRNAs was altered in response to PCUN or PIUN and that there is evidence that these changes may underlie the changes in the protein abundance of key regulators of hepatic fatty acid β-oxidation in the PCUN and PIUN groups. Therefore, embryo number and the timing of maternal undernutrition in early pregnancy have a differential impact on hepatic microRNA expression and on the factors that regulate hepatic fatty acid oxidation and lipid synthesis.

scholarly journals Berberine ameliorates fatty acid-induced oxidative stress in human hepatoma cells

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Yixuan Sun ◽  
Xinlu Yuan ◽  
Feifei Zhang ◽  
Yamei Han ◽  
Xinxia Chang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Fatty Acid ◽  
Hepatoma Cells ◽  
Human Hepatoma ◽  
Human Hepatoma Cells

Cheese can reduce indexes that estimate fatty acid desaturation. Results from the Oslo Health Study and from experiments with human hepatoma cells

2012 ◽  
Vol 37 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Arne T. Høstmark ◽  
Marianne S.H. Lunde
Keyword(s):  
Fatty Acid ◽  
Hepg2 Cells ◽  
Causal Effect ◽  
Fatty Acid Distribution ◽  
Hepatoma Cells ◽  
Fatty Acid Desaturation ◽  
Health Study ◽  
Human Hepatoma ◽  
Human Hepatoma Cells ◽  
Δ9 Desaturase

Previously, cheese intake was shown to be inversely related to serum triglycerides, raising the possibility that cheese might inhibit triglyceride synthesis, which is governed by fatty acid desaturases. Therefore, analyses were done to study whether cheese intake was associated with indexes that reflect fatty acid desaturation in 121 healthy ethnic Norwegians aged 40–45 years, a subsample from the Oslo Health Study (N = 18 777). Experiments with human hepatoma cells (HepG2) were done to clarify whether cheese might have a causal effect on desaturases. Fatty acid distribution in lipids of human sera and HepG2 cells was determined by gas chromatography. Δ9-Desaturase was estimated by the (16:1,n-7)/(16:0) and (18:1,n-9)/(18:0) ratios, abbreviated ds9_1 and ds9_2, and Δ5-desaturase (ds5) by the (20:4,n-6)/(18:2,n-6) ratio. Correlation, ANOVA, and multiple linear regression models were used to study associations. Oslo Health Study: Subjects with cheese intake >4–6 times per week had 33% lower ds9_1 and 16% lower ds5 than subjects with intake ≤ 4–6 times per week. The cheese intake vs. ds5 association prevailed when adjusting for sex, time since last meal, fatty fish, vegetables, fruit–berries, fruit juice, cod liver oil, coffee, alcohol, body mass index, physical activity, length of education, and smoking. HepG2 cells: An ethanol extract of Jarlsberg cheese lowered the desaturase indexes. Inhibition of ds9_1 increased with increasing amount cheese extract added. Thus, cheese may contain inhibitors of desaturases, thereby providing an explanation for the previously reported negative association between cheese intake and triglycerides.

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