107 research outputs found

    Lipoproteins and Cancer

    Get PDF

    Oral administration of coprostanol producing microorganisms to humans to decrease plasma cholesterol concentration

    Get PDF
    A method of decreasing plasma cholesterol is disclosed. The method includes oral administration of coprostanol-producing bacteria to humans. These organisms, once in the small intestine, will reduce free cholesterol to coprostanol, which is absorbed poorly. Pharmaceutical compositions for delivery are included as are different methods of delivery such as placing the microorganisms in food

    Multi-Omics Approach Reveals Dysregulation of Protein Phosphorylation Correlated with Lipid Metabolism in Mouse Non-Alcoholic Fatty Liver

    Get PDF
    Obesity caused by overnutrition is a major risk factor for non-alcoholic fatty liver disease (NAFLD). Several lipid intermediates such as fatty acids, glycerophospholipids and sphingolipids are implicated in NAFLD, but detailed characterization of lipids and their functional links to proteome and phosphoproteome remain to be elucidated. To characterize this complex molecular relationship, we used a multi-omics approach by conducting comparative proteomic, phoshoproteomic and lipidomic analyses of high fat (HFD) and low fat (LFD) diet fed mice livers. We quantified 2447 proteins and 1339 phosphoproteins containing 1650 class I phosphosites, ofwhich 669 phosphositeswere significantly different between HFD and LFD mice livers. We detected alterations of proteins associated with cellular metabolic processes such as small molecule catabolic process, monocarboxylic acid, long- and medium-chain fatty acid, and ketone body metabolic processes, and peroxisome organization. We observed a significant downregulation of protein phosphorylation in HFD fed mice liver in general. Untargeted lipidomics identified upregulation of triacylglycerols, glycerolipids and ether glycerophosphocholines and downregulation of glycerophospholipids, such as lysoglycerophospholipids, as well as ceramides and acylcarnitines. Analysis of differentially regulated phosphosites revealed phosphorylation dependent deregulation of insulin signaling as well as lipogenic and lipolytic pathways during HFD induced obesity. Thus, this study reveals amolecular connection between decreased protein phosphorylation and lipolysis, as well as lipid-mediated signaling in diet-induced obesity

    Endurance Exercise Training Programs Intestinal Lipid Metabolism in a Rat Model of Obesity and Type 2 Diabetes

    Get PDF
    Endurance exercise has been shown to improve metabolic outcomes in obesity and type 2 diabetes; however, the physiological and molecular mechanisms for these benefits are not completely understood. Although endurance exercise has been shown to decrease lipogenesis, promote fatty acid oxidation (FAO), and increase mitochondrial biosynthesis in adipose tissue, muscle, and liver, its effects on intestinal lipid metabolism remain unknown. The absorptive cells of the small intestine, enterocytes, mediate the highly efficient absorption and processing of nutrients, including dietary fat for delivery throughout the body. We investigated how endurance exercise altered intestinal lipid metabolism in obesity and type 2 diabetes using Otsuka Long-Evans Tokushima Fatty (OLETF) rats. We assessed mRNA levels of genes associated with intestinal lipid metabolism in nonhyperphagic, sedentary Long-Evans Tokushima Otsuka (LETO) rats (L-Sed), hyperphagic, sedentary OLETF rats (O-Sed), and endurance exercised OLETF rats (O-EndEx). O-Sed rats developed hyperphagia-induced obesity (HIO) and type 2 diabetes compared with L-Sed rats. O-EndEx rats gained significantly less weight and fat pad mass, and had improved serum metabolic parameters without change in food consumption compared to O-Sed rats. Endurance exercise resulted in dramatic up-regulation of a number of genes in intestinal lipid metabolism and mitochondrial content compared with sedentary rats. Overall, this study provides evidence that endurance exercise programs intestinal lipid metabolism, likely contributing to its role in improving metabolic outcomes in obesity and type 2 diabetes

    Diet Induced Obesity Alters Intestinal Cytoplasmic Lipid Droplet Morphology and Proteome in the Postprandial Response to Dietary Fat

    Get PDF
    Dietary fat absorption by the small intestine is an efficient, multistep process that regulates the uptake and delivery of essential nutrients and energy. Fatty acids taken up by enterocytes, the absorptive cells of the small intestine, are resynthesized into triacylglycerol (TAG) and either secreted in chylomicrons or temporarily stored in cytoplasmic lipid droplets (CLDs). Proteins that associate with CLDs are thought to regulate the dynamics of TAG storage and mobilization. It is currently unclear what effect diet induced obesity (DIO) has on the balance between dietary fat storage and secretion. Specifically, there is limited knowledge of how DIO affects the level and diversity of proteins that associate with CLDs and regulate CLD dynamics. In the current study, we characterize CLDs from lean and DIO mice through histological and proteomic analyses. We demonstrate that DIO mice have larger intestinal CLDs compared to lean mice in response to dietary fat. Additionally, we identified 375 proteins in the CLD fraction isolated from enterocytes of lean and DIO mice. We identified a subgroup of lipid related proteins that are either increased or unique to the DIO CLD proteome. These proteins are involved in steroid synthesis, TAG synthesis, and lipolysis. This analysis expands our knowledge of the effect of DIO on the process of dietary fat absorption in the small intestine (D’Aquila, 2016)

    Tunneling into a two-dimensional electron system in a strong magnetic field

    Full text link
    We investigate the properties of the one-electron Green's function in an interacting two-dimensional electron system in a strong magnetic field, which describes an electron tunneling into such a system. From finite-size diagonalization, we find that its spectral weight is suppressed near zero energy, reaches a maximum at an energy of about 0.2e2/ϵlc0.2e^{2}/\epsilon l_{c}, and decays exponentially at higher energies. We propose a theoretical model to account for the low-energy behavior. For the case of Coulomb interactions between the electrons, at even-denominator filling factors such as ν=1/2\nu=1/2, we predict that the spectral weight varies as eω0/ωe^{-\omega_0/|\omega|}, for ω0\omega\rightarrow 0

    Cholesterol Sulfonation Enzyme, SULT2B1b, Modulates AR and Cell Growth Properties in Prostate Cancer

    Get PDF
    Cholesterol accumulates in prostate lesions and has been linked to prostate cancer (PCa) incidence and progression. However, how accumulated cholesterol contributes to PCa development and progression is not completely understood. Cholesterol sulfate (CS), the primary sulfonation product of cholesterol sulfotransferase (SULT2B1b), accumulates in human prostate adenocarcinoma and precancerous prostatic intraepithelial neoplasia (PIN) lesions compared to normal regions of the same tissue sample. Given the enhanced accumulation of CS in these lesions, it was hypothesized that SULT2B1b-mediated production of CS provides a growth advantage to these cells. To address this, PCa cells with RNAi-mediated knockdown (KD) of SULT2B1b were used to assess the impact on cell growth and survival. SULT2B1b is expressed and functional in a variety of prostate cells and the data demonstrate that SULT2B1b KD, in LNCaP and other androgen-responsive (VCaP and C4-2) cells, results in decreased cell growth/viability and induces cell death. SULT2B1b KD also decreases androgen receptor (AR) activity and expression at mRNA and protein levels. While AR overexpression has no impact on SULT2B1b KD-mediated cell death, addition of exogenous androgen is able to partially rescue the growth inhibition induced by SULT2B1b KD in LNCaP cells. These results suggest that SULT2B1b positively regulates the AR either through alterations in ligand availability or by interaction with critical co-regulators that influence AR activity

    Multidirectional Time-Dependent Effect of Sinigrin and Allyl Isothiocyanate on Metabolic Parameters in Rats

    Get PDF
    Sinigrin (SIN) and allyl isothiocyanate (AITC) are compounds found in high concentrations in Brassica family vegetables, especially in Brussels sprouts. Recently, they have been used as a nutrition supplement for their preventive and medicinal effect on some types of cancer and other diseases. In this research, nutritional significance of parent glucosinolate sinigrin 50 μmol/kg b. w./day and its degradation product allyl isothiocyanate 25 μmol/kg b. w./day and 50 μmol/kg b. w./day was studied by the evaluation of their influence on some parameters of carbohydrate and lipid metabolism in an animal rat model in vivo after their single (4 h) and 2 weeks oral administration. Additionally, the aim of this trial was to evaluate the direct action of AITC on basal and epinephrine-induced lipolysis in isolated rat adipocytes at concentration 1 μM, 10 μM and 100 μM in vitro. Sole AITC after 4 h of its ingestion caused liver triacylglycerols increment at both doses and glycaemia only at the higher dose. Multiple SIN treatment showed its putative bioconversion into AITC. It was found that SIN and AITC multiple administration in the same way strongly disturbed lipid and carbohydrate homeostasis, increasing esterified and total cholesterol, free fatty acids and lowering tracylglycerols in the blood serum. Additionally, AITC at both doses elevated insulinaemia and liver glycogen enhancement. The in vitro experiment revealed that AITC potentiated basal lipolysis process at 10 μM, and had stimulatory effect on epinephrine action at 1 μM and 10 μM. The results of this study demonstrated that the effect of SIN and AITC is multidirectional, indicating its impact on many organs like liver as well as pancreas, intestine in vivo action and rat adipocytes in vitro. Whilst consumption of cruciferous vegetables at levels currently considered “normal” seems to be beneficial to human health, this data suggest that any large increase in intake could conceivably lead to undesirable effect. This effect is potentiated with time of action of the examined compounds, whose influence is rather adverse for the majority of metabolic pathways (liver steatosis at short duration and insulinaemia, cholesterolaemia at long time treatment). Beneficial action of AITC concerned intensified hydrolysis of TG in the blood serum with a simultaneous lipolysis in adipocytes

    Triacylglycerol Synthesis Enzymes Mediate Lipid Droplet Growth by Relocalizing from the ER to Lipid Droplets

    Get PDF
    Lipid droplets (LDs) store metabolic energy and membrane lipid precursors. With excess metabolic energy, cells synthesize triacylglycerol (TG) and form LDs that grow dramatically. It is unclear how TG synthesis relates to LD formation and growth. Here, we identify two LD subpopulations: smaller LDs of relatively constant size, and LDs that grow larger. The latter population contains isoenzymes for each step of TG synthesis. Glycerol-3-phosphate acyltransferase 4 (GPAT4), which catalyzes the first and rate-limiting step, relocalizes from the endoplasmic reticulum (ER) to a subset of forming LDs, where it becomes stably associated. ER-to-LD targeting of GPAT4 and other LD-localized TG synthesis isozymes is required for LD growth. Key features of GPAT4 ER-to-LD targeting and function in LD growth are conserved between Drosophila and mammalian cells. Our results explain how TG synthesis is coupled with LD growth and identify two distinct LD subpopulations based on their capacity for localized TG synthesis
    corecore