Target Genes FAS Research Articles

Yeast-Hydrolysate-Derived 1-Methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic Acid Inhibits Fat Accumulation during Adipocyte Differentiation.

This study aimed to investigate the impact of yeast hydrolysate (YH) on lipogenesis, elucidate its mechanistic action, and identify the active compounds responsible for its anti-adipogenic effects. YH (2 mg/mL) significantly reduced Oil Red O-stained lipids. YH (2 mg/mL) also downregulated C/EBPβ and upregulated KLF2, both of which are early adipogenic factors. Moreover, YH (2 mg/mL) decreased C/EBPα, PPARγ, FABP4, FAS, ACC, and HMGCR mRNA expression. Additionally, YH significantly downregulated SEBP1c and SREBP2 and their target genes, which govern fatty acid and cholesterol metabolism; however, 2 mg/mL YH had a greater suppressive effect on SREBP1c than on SREBP2. YH (2 mg/mL) also significantly reduced the mRNA level of G6PD and malic enzyme, which are enzymes that synthesize NADPH for lipid synthesis, compared with the control. Furthermore, 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA) was identified as the active compound with anti-adipogenic effects using solvent fractionation and chromatographic analysis of YH, and 1.1 μg/mL MTCA significantly downregulated SREBP1c/SREBP2 mRNAs by 47.8% and 69.2%, respectively, along with the target genes FAS, ACC, and HMGCR by 79.0%, 77.0%, and 40.9%, respectively. Collectively, YH effectively suppressed adipogenic lipid storage by downregulating SREBP- and NADPH-synthesizing genes. These findings suggest that YH containing MTCA has the potential to act as an anti-obesity agent.

Peroxisome proliferator-activated receptor pathways in diabetic rat decidua early after implantation: regulation by dietary polyunsaturated fatty acids

Research questionAre peroxisome proliferator-activated receptor (PPAR) pathways and moieties involved in histotrophic nutrition altered in the decidua of diabetic rats? Can diets enriched in polyunsaturated fatty acids (PUFA) administered early after implantation prevent these alterations? Can these dietary treatments improve morphological parameters in the fetus, decidua and placenta after placentation? DesignStreptozotocin-induced diabetic Albino Wistar rats were fed a standard diet or diets enriched in n3- or n6-PUFAs early after implantation. Decidual samples were collected on day 9 of pregnancy. Fetal, decidual and placental morphological parameters were evaluated on day 14 of pregnancy. ResultsOn gestational day 9, PPARδ levels showed no changes in the diabetic rat decidua compared with controls. In diabetic rat decidua, PPARα levels and the expression of its target genes Aco and Cpt1 had reduced. These alterations were prevented by the n6-PUFA-enriched diet. Levels of PPARγ, the expression of its target gene Fas, lipid droplet number and perilipin 2 and fatty acid binding protein 4 levels increased in the diabetic rat decidua compared with controls. Diets enriched with PUFA prevented PPARγ increase, but not the increased lipid-related PPARγ targets. On gestational day 14, fetal growth, decidual and placental weight reduced in the diabetic group, and alterations prevented by the maternal diets were enriched in PUFAs. ConclusionWhen diabetic rats are fed diets enriched in n3- and n6-PUFAs early after implantation, PPAR pathways, lipid-related genes and proteins, lipid droplets and glycogen content in the decidua are modulated. This influences decidual histotrophic function and later feto-placental development.

Selection and evaluation of reference genes for quantitative real‐time PCR analysis in lac insect (Kerria lacca)

AbstractThe screening and identification of suitable reference genes are key steps in experiments involving the quantitative real‐time polymerase chain reaction. However, the reference genes of Kerria lacca, a lac insect with considerable economic significance, have not been investigated. In this study, we used five statistical algorithms (ΔCt, geNorm, NormFinder, BestKeeper, and RefFinder) to evaluate the stability of eight candidate reference genes (18S rRNA, 28S rRNA, β‐ACT, EF1‐α, RPL10, RPL13, RPS11, and RPS15) in different developmental stages and tissues of K. lacca and under dsRNA treatment. Our results showed that the most stable reference genes were 28S rRNA and RPS11 for the developmental stages, RPL13 and RPS11 for different tissues, and β‐ACT and EF1‐α for dsRNA treatments. Although the target genes FAS and 17β‐HSD showed consistent expression profiles (alone or in combination) when normalized to the expression levels of the stable genes, those changed when the least stable reference gene (18S rRNA) was used. These results highlight that suitable reference genes should be chosen according to the specific experimental conditions used. The reliability and stability of different reference genes can provide a firm foundation for gene expression analysis in lac insects.

Regulation of mammary lipogenic genes in dairy cows fed crushed sunflower seeds

The main objective of this study was to investigate the effects of increasing dietary supplementation of crushed sunflower seeds (CSS) in dairy cow diet on mammary expression of genes involved in de novo fatty acid (FA) synthesis, FA desaturation, FA transport/uptake, cholesterol homeostasis, and regulation of transcription. Twenty-four cows were allocated to one of four diets supplemented with CSS at 0% (Control), 5%, 10%, or 15% of dry matter in randomized block design. After a five week experimental period, mammary tissue was biopsied, and milk and plasma samples were obtained. Milk proportion of preformed FA was increased at all levels of CSS supplementation while the proportion of FA ≤ C16 was reduced. This change in milk fat composition was reflected in a sustained mammary transcription of genes involved in FA transport, i.e. Lipoprotein Lipase (LPL), Fatty Acid Binding Protein 3 (FABP3), and FA Translocase, and a reduced transcription of a gene involved in regulation of transcription, i.e. Sterol Response Element Binding Factor 1 (SREBF1) as well as genes involved in FA synthesis in cows supplemented with CSS. Milk proportion of unsaturated fatty acids (UFA) was increased from 27.5% in control to 40.3% and 43.0% of total FA in cows supplemented with 10 and 15% CSS, respectively, in spite of reduced mammary transcription of two desaturase enzymes, i.e. Stearoyl CoA Desaturase 1 (SCD1) and FA Desaturase 1 (FADS1) in these two treatment groups. Transcription of Sterol Response Element Binding Protein Cleavage Activating Protein (SCAP), Niemann Pick disease type 1C (NPC1) and Acetyl-CoA Carboxylase α (ACAC) were also reduced by CSS supplementation to various degrees. Transcription of Insulin Induced Gene 1 (INSIG1), FA Desaturase 2 (FADS2), and ATP Binding Cassette, sub-family G member 2 (ABCG2) was not significantly changed by CSS supplementation. Our data show a coordinated down-regulation of mammary transcription of major lipogenic transcription factor, SREBF1, its target genes FAS and ACAC, and its activator protein SCAP during lipid supplementation even though overall milk fat secretion was unaltered.

Corosolic Acid Attenuates Hepatic Lipid Accumulation and Inflammatory Response via AMPK/SREBPs and NF-B/MAPK Signaling Pathways.

Corosolic acid (CA) is the main active component of Lagetstroemia speciosa and has been known to serve as several different pharmacological effects, such as antidiabetic, anti-oxidant, and anticancer effects. In this study, effects of CA on the hepatic lipid accumulation were examined using HepG2 cells and tyloxapol (TY)-induced hyperlipidemia ICR mice. CA significantly inhibited hepatic lipid accumulation via inhibition of SREBPs, and its target genes FAS, SCD1, and HMGCR transcription in HepG2 cells. These effects were mediated through activation of AMPK, and these effects were all abolished in the presence of compound C (CC, an AMPK inhibitor). In addition, CA clearly alleviated serum ALT, AST, TG, TC, low-density lipoprotein cholesterol (LDL-C), and increased high-density lipoprotein cholesterol (HDL-C) levels, and obviously attenuated TY-induced liver steatosis and inflammation. Moreover, CA significantly upregulated AMPK, ACC, LKB1 phosphorylation, and significantly inhibited lipin1, SREBPs, TNF-, F4/80, caspase-1 expression, NF-B translocation, and MAPK activation in TY-induced hyperlipidemia mice. Our results suggest that CA is a potent antihyperlipidemia and antihepatic steatosis agent and the mechanism involved both lipogenesis and cholesterol synthesis and inflammation response inhibition via AMPK/SREBPs and NF-B/MAPK signaling pathways.

The effect of fasting on the appetite-associated factors and energy sensors expression in the hypothalamus of different TI broilers

Tonic immobility (TI) is a behaviour related to fear and stress response. Birds can exhibit a short (STI) or long (LTI) tonic immobility phenotype on the basis in TI duration. In this study, the differences in the hypothalamic appetite-associated factors and energy sensor gene expression between STI and LTI broilers were evaluated under free feed access or 16-h fasting. The results showed that the concentrations of cholesterol, high density lipoprotein-cholesterol, non-esterified fatty acid, malonaldehyde, lactate dehydrogenase, creatine kinase, alanine aminotransferase and aspartate aminotransferase in plasma were significantly increased (P < 0.05) in fasting broilers compared with broilers fed ad libitum, whereas plasma glucose, triglyceride, and total antioxidant capacity concentrations were decreased (P < 0.05). With respect to TI, however, only low density lipoprotein-cholesterol and glutathione peroxidase concentrations in plasma showed significant differences between LTI and STI broilers, with higher concentrations in LTI compared with STI. Real-time PCR results showed that only NPY mRNA expression demonstrated a tendency to increase in STI broilers compared with LTI (P = 0.095). Fasting downregulated SREBP-1 and its target gene FAS but upregulated CPT1 in the hypothalamus. Additionally, levels of hypothalamic p-GR and p-AMPK protein expression decreased after fasting. These results indicate that a 16-h fasting results in a negative energy status, and is accompanied with changes in expression of hypothalamic energy sensor and appetite-associated factors.

MicroRNA-133b-5p Is Involved in Cardioprotection of Morphine Preconditioning in Rat Cardiomyocytes by Targeting Fas

BackgroundMicroRNAs (miRNAs) have been implicated in ischemia-reperfusion injury and ischemic preconditioning. Opioid pre- and postconditioning have powerful protective effects on the heart, but it is still not known whether miRNAs are involved in opioid-induced cardioprotection. The present study was designed to investigate the role of miRNAs in morphine preconditioning (MPC)-induced cardioprotection. MethodsMiRNA microarray analysis was performed to examine the differentially expressed miRNAs caused by MPC in adult rat cardiomyocytes. A dual-luciferase reporter assay was performed to confirm the direct regulation of miR-133b-5p on the target gene Fas. MiR-133b-5p mimic or inhibitor was separately transfected into myocardial H9c2 cells to examine the role of miR-133b-5p in morphine-induced cardioprotection. ResultsMPC protected adult rat cardiomyocytes against hypoxia/reoxygenation (H/R) injury by reducing cell injury and death. MiRNA microarray data showed that a total of 39 miRNAs were differentially expressed after MPC treatment. A Dual-luciferase reporter assay confirmed that miR-133b-5p directly targets the Fas gene. After H/R injury, the decrease in miR-133b-5p and a contemporaneous rise in Fas mRNA and protein levels in adult rat cardiomyocytes were prevented by MPC treatment. In H9c2 cardiomyocytes, overexpression of miR-133b-5p reduced H/R-induced cell injury and apoptosis by inhibiting Fas expression. Knockdown of miR-133b-5p blocked morphine-mediated cardioprotection by reducing miR-133b-5p levels while enhancing the expression of Fas mRNA and protein. ConclusionsMPC causes a change in miRNA expression in rat cardiomyocytes. Morphine may protect cardiomyocytes against H/R injury through upregulation of miR-133b-5p by targeting Fas.

Adipose tissue gene expression in adult rats fed with highfructose diet. Effects of EPA supplementation

The study of the expression of genes involved in obesity‐related disorders has been promising for a better understanding of the links between components of the metabolic syndrome.Our aim was to measure the effects of a high‐fructose diet on metabolic status and on the mRNA expression of several genes involved in insulin‐signaling pathway, and glucido‐lipid metabolism in rats, and to assess the effects of EPA supplementation.Rats were given for 10 wk either a control or a high‐fructose diet (65% fructose cal), supplemented or not with EPA (120 mg/d). At the end of the 10‐wk period, body composition and IS were assessed, lipid plasma were assayed, and mRNA expression of insulin receptor, IRS1, perilipin, leptin, ACC, FAS, HSL, LPL, GLUT, TNFα, SREBP‐1c, PPARγ was semi‐quantified from adipose tissue biopsies.In high‐fructose rats, IS tended to be lower, plasma triglyceride level tended to be higher, and Glut4 expression was lower than in control rats. In rats fed with high‐fructose diet plus EPA, plasma NEFA concentration was lower, and PPARγ and FAS mRNA levels were higher than in rats fed with unsupplemented high fructose diet.Our results show change in Glut4 expression in rats fed highfructose diet that could reflect an alteration of glucose uptake, and impair systemic IS. They also show that EPA could stimulate transcription of PPARγ and its target gene FAS that could account for its beneficial effect on lipidemia.

Suppression of 2,3-Oxidosqualene Cyclase by High Fat Diet Contributes to Liver X Receptor-α-mediated Improvement of Hepatic Lipid Profile

The liver X receptors (LXRs) sense oxysterols and regulate genes involved in cholesterol metabolism. Synthetic agonists of LXRs are potent stimulators of fatty acid synthesis, which is mediated largely by sterol regulatory element-binding protein-1c (SREBP-1c). Paradoxically, an improved hepatic lipid profile by LXR was observed in mice fed a Western high fat (HF) diet. To explore the underlying mechanism, we administered mice normal chow or an HF diet and overexpressed LXRalpha in the liver. The HF diet with tail-vein injection of adenovirus of LXRalpha increased the expression of LXR-targeted genes involved in cholesterol reverse transport but not those involved in fatty acid synthesis. A similar effect was also observed with the use of 22R-hydroxycholesterol, an LXR ligand, in cultured hepatocytes. Consequently, SREBP-1c maturation was inhibited by the HF diet, which resulted from the induction of Insig-2a. Importantly, increased cholesterol level suppressed the expression of 2,3-oxidosqualene cyclase (OSC), which led to an increase in endogenous LXR ligand(s). Furthermore, siRNA-mediated knockdown of OSC expression enhanced LXR activity and selectively up-regulated LXR-targeted genes involved in cholesterol reverse transport. Thus, down-regulation of OSC may account for a novel mechanism underlying the LXR-mediated lipid metabolism in the liver of mice fed an HF diet.

Soy protein reduces hepatic lipotoxicity in hyperinsulinemic obese Zucker fa/fa rats

Hepatic steatosis is commonly present during the development of insulin resistance, and it is a clear sign of lipotoxicity attributable in part to an accelerated lipogenesis. There is evidence that a soy protein diet prevents the overexpression of hepatic sterol-regulatory element binding protein-1 (SREBP-1), decreasing lipid accumulation. Therefore, the aim of the present work was to study whether a soy protein diet may prevent the development of fatty liver through the regulation of transcription factors involved in lipid metabolism in hyperinsulinemic and hyperleptinemic Zucker obese fa/fa rats. Serum and hepatic cholesterol and triglyceride levels, as well as VLDL-triglyceride and LDL-cholesterol, were significantly lower in rats fed soy protein than in rats fed a casein diet for 160 days. The reduction in hepatic cholesterol was associated with a low expression of liver X receptor-alpha and its target genes, 7-alpha hydroxylase and ABCA1. Soy protein also decreased the expression of SREBP-1 and several of its target genes, FAS, stearoyl-CoA desaturase-1, and delta5 and delta6 desaturases, decreasing lipogenesis even in the presence of hyperinsulinemia. Reduction in SREBP-1 was not associated with the presence of soy isoflavones. Finally, soy protein reduced SREBP-1 expression in adipocytes, preventing hypertrophy, which also helps prevent the development of hepatic lipotoxicity.