18 research outputs found

    NCoR Repression of LXRs Restricts Macrophage Biosynthesis of Insulin-Sensitizing Omega 3 Fatty Acids

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    SummaryMacrophage-mediated inflammation is a major contributor to obesity-associated insulin resistance. The corepressor NCoR interacts with inflammatory pathway genes in macrophages, suggesting that its removal would result in increased activity of inflammatory responses. Surprisingly, we find that macrophage-specific deletion of NCoR instead results in an anti-inflammatory phenotype along with robust systemic insulin sensitization in obese mice. We present evidence that derepression of LXRs contributes to this paradoxical anti-inflammatory phenotype by causing increased expression of genes that direct biosynthesis of palmitoleic acid and ω3 fatty acids. Remarkably, the increased ω3 fatty acid levels primarily inhibit NF-κB-dependent inflammatory responses by uncoupling NF-κB binding and enhancer/promoter histone acetylation from subsequent steps required for proinflammatory gene activation. This provides a mechanism for the in vivo anti-inflammatory insulin-sensitive phenotype observed in mice with macrophage-specific deletion of NCoR. Therapeutic methods to harness this mechanism could lead to a new approach to insulin-sensitizing therapies

    Scale and the Origins of Structural Change

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    Structural change involves a broad set of trends: (i) sectoral reallocations, (ii) rich movements of productive activities between home and market, and (iii) an increase in the scale of productive units. After extending these facts, we develop a model to explain them within a unified framework. The crucial distinction between manufacturing, services, and home production is the scale of the productive unit. Scale technologies give rise to industrialization and the marketization of previously home produced activities. The rise of mass consumption leads to an expansion of manufacturing, but a reversal of the marketization process for service industries. Finally, the later growth in the scale of services leads to a decline in industry and a rise in services

    Capital Charges under Basel II: Corporate Credit Risk Modelling and the Macroeconomy

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    The Internal Ratings Based (IRB) approach for capital determination is one of the cornerstones in the proposed revision of the Basel Committee rules for bank regulation. We evaluate the IRB approach using historical business loan portfolio data from a major Swedish bank for the period 1994 to 2000. First, we estimate a duration model that takes into account both company, loan related and macroeconomic variables. Next, we obtain a Value-at-Risktype (VaR) credit risk measure, by model-based simulations. Moreover, we study how both the banks credit risk and bu.er capital changes over time (had the bank been subject to the proposed rules). This approach allows us to (i) make individual forecasts of default risk conditional on company, loan and macro variables, (ii) study portfolio credit risk over time, (iii) assess to what extent the new Accord will achieve its main objective of increasing credit risk sensitivity in minimal capital charges, and (iv) compare current capital requirements to those under the proposed system. Our results show that macro conditions have great explanatory power in predicting default risk and calculating credit risk. The IRB approach, although sensitive to the choice of some horizon parameters, is an achievement in the intended direction

    Liver fatty acid-binding protein binds monoacylglycerol in vitro and in mouse liver cytosol.

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    Liver fatty acid-binding protein (LFABP; FABP1) is expressed both in liver and intestinal mucosa. Mice null for LFABP were recently shown to have altered metabolism of not only fatty acids but also monoacylglycerol, the two major products of dietary triacylglycerol hydrolysis (Lagakos et al., Am J Physiol. 2011). Nevertheless, the binding and transport of MG by LFABP is uncertain, with conflicting reports in the literature as to whether this single chain amphiphile is in fact bound by LFABP. In the present studies, gel filtration chromatography of liver cytosol from LFABP-/- mice shows the absence of the low molecular weight peak of radiolabeled monoolein present in the fractions that contain LFABP in cytosol from wild type mice, indicating that LFABP binds sn-2 MG in vivo. Further, solution state NMR spectroscopy demonstrates two molecules of sn-2-monoolein bound in the LFABP binding pocket, in positions similar to those found for oleate binding. Equilibrium binding affinities are approximately two-fold lower for MG compared to FA. Finally, kinetic studies examining the transfer of a fluorescent MG analogue show that the rate of transfer of MG is 7-fold faster from LFABP to phospholipid membranes than from membranes to membranes, and occurs by an aqueous diffusion mechanism. These results provide strong support for monoacylglycerol as a physiological ligand for LFABP, and further suggest that LFABP functions in the efficient intracellular transport of MG.Fil: Lagakos, William S.. State University of New Jersey; Estados UnidosFil: Guan, Xudong. City University of New York; Estados UnidosFil: Ho, Shiu Ying. State University of New Jersey; Estados UnidosFil: Rodriguez Sawicki, Luciana. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂ­micas de La Plata ; ArgentinaFil: CĂłrsico, Betina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂ­micas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂ©dicas. Instituto de Investigaciones BioquĂ­micas de La Plata ; ArgentinaFil: Kodukula, Sarala. Kinki University; JapĂłnFil: Murota, Kaeko. Kinki University; JapĂłnFil: Stark, Ruth E.. City University of New York; Estados UnidosFil: Storch, Judith. State University of New Jersey; Estados Unido

    Metabolism of apical versus basolateral sn-2-monoacylglycerol and fatty acids in rodent small intestine*

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    The metabolic fates of radiolabeled sn-2-monoacylglycerol (MG) and oleate (FA) in rat and mouse intestine, added in vivo to the apical (AP) surface in bile salt micelles, or to the basolateral (BL) surface via albumin-bound solution, were examined. Mucosal lipid products were quantified, and the results demonstrate a dramatic difference in the esterification patterns for both MG and FA, depending upon their site of entry into the enterocyte. For both lipids, the ratio of triacylglycerol to phospholipid (TG:PL) formed was approximately 10-fold higher for delivery at the AP relative to the BL surface. Further, a 3-fold higher level of FA oxidation was found for BL compared with AP substrate delivery. Incorporation of FA into individual PL species was also significantly different, with >2-fold greater incorporation into phosphatidylethanolamine (PE) and a 3-fold decrease in the phosphatidylcholine:PE ratio for AP- compared with BL-added lipid. Overnight fasting increased the TG:PL incorporation ratio for both AP and BL lipid addition, suggesting that metabolic compartmentation is a physiologically regulated phenomenon. These results support the existence of separate pools of TG and glycerolipid intermediates in the intestinal epithelial cell, and underscore the importance of substrate trafficking in the regulation of enterocyte lipid metabolism
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