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Sample records for human apolipoprotein ai

  1. Optimized bacterial expression of human apolipoprotein A-I.

    PubMed

    Ryan, Robert O; Forte, Trudy M; Oda, Michael N

    2003-01-01

    Apolipoprotein A-I (apoA-I) serves critical functions in plasma lipoprotein metabolism as a structural component of high density lipoprotein, activator of lecithin:cholesterol acyltransferase, and acceptor of cellular cholesterol as part of the reverse cholesterol transport pathway. In an effort to facilitate structure:function studies of human apoA-I, we have optimized a plasmid vector for production of recombinant wild type (WT) and mutant apoA-I in bacteria. To facilitate mutagenesis studies, subcloning, and DNA manipulation, numerous silent mutations have been introduced into the apoA-I cDNA, generating 13 unique restriction endonuclease sites. The coding sequence for human apoA-I has been modified by the introduction of additional silent mutations that eliminate 18 separate codons that employ tRNAs that are of low or moderate abundance in Escherichia coli. Yields of recombinant apoA-I achieved using the optimized cDNA were 100+/-20 mg/L bacterial culture, more than fivefold greater than yields routinely obtained with the original cDNA. Site-directed mutagenesis of the apoA-I cDNA was performed to generate a Glu2Asp mutation in the N-terminal sequence of apoA-I. This modification, which creates an acid labile Asp-Pro peptide bond between amino acids 2 and 3, permits specific chemical cleavage of an N-terminal His-Tag fusion peptide used for rapid protein purification. The product protein's primary structure is identical to WT apoA-I in all other respects. Together, these changes in apoA-I cDNA and bacterial expression protocol significantly improve the yield of apoA-I protein without compromising the relative ease of purification.

  2. Localization of the structural gene for human apolipoprotein A-I on the long arm of human chromosome 11.

    PubMed Central

    Cheung, P; Kao, F T; Law, M L; Jones, C; Puck, T T; Chan, L

    1984-01-01

    Apolipoprotein A-I (apo A-I), the major apolipoprotein in human high density lipoproteins, is involved in the disease atherosclerosis. Cloned apo A-I cDNA (pA1-3) was used as a probe in chromosome mapping studies to detect the human apo A-I structural gene sequence in human-Chinese hamster cell hybrids. Southern blot analysis of 13 hybrids localized the gene to human chromosome 11. Confirmation of the chromosomal assignment was obtained by analysis of a hybrid (J1) containing a single human chromosome, no. 11. Regional mapping was achieved by using deletion subclones of J1 that localized the human apo A-I structural gene to the region 11q13 leads to qter. Since the human apolipoprotein C-III (apo C-III) structural gene is closely linked to apo A-I, it can be assigned to the same region on the long arm of chromosome 11. By extension of methods previously described, it now appears possible to carry out fine-structure analysis of this and related gene regions on chromosome 11 and to study the biochemical concomitants of these genes and of genes on other chromosomes for analysis of their role in atherosclerosis. Images PMID:6420790

  3. The apolipoprotein CIII enhancer regulates both extensive histone modification and intergenic transcription of human apolipoprotein AI/CIII/AIV genes but not apolipoprotein AV.

    PubMed

    Li, Ya-Jun; Wei, Yu-Sheng; Fu, Xiang-Hui; Hao, De-Long; Xue, Zheng; Gong, Huan; Zhang, Zhu-Qin; Liu, De-Pei; Liang, Chih-Chuan

    2008-10-17

    The apolipoprotein (apo) AI/CIII/AIV/AV cluster genes are expressed at different levels in the liver and intestine. The apoCIII enhancer, a common regulatory element, regulates the tissue-specific expression of apoAI, apoCIII, and apoAIV but not apoAV. To study this regulation at the chromatin level, the histone modifications and intergenic transcription in the human apoAI/CIII/AIV/AV cluster were investigated in HepG2 and Caco-2 cells and in the livers of transgenic mice carrying the human gene cluster constructs with or without the apoCIII enhancer. We found that both the promoters and the intergenic regions of the apoAI/CIII/AIV genes were hyperacetylated and formed an open subdomain that did not include the apoAV gene. Hepatic and intestinal intergenic transcripts were identified to transcribe bidirectionally with strand preferences along the cluster. The deletion of the apoCIII enhancer influenced both histone modification and intergenic transcription in the apoAI/CIII/AIV gene region. These results demonstrate that the apoCIII enhancer contributes to the maintenance of an active chromatin subdomain of the apoAI/CIII/AIV genes, but not apoAV.

  4. Production and Analysis of Biological Properties of Recombinant Human Apolipoprotein A-I.

    PubMed

    Ryabchenko, A V; Kotova, M V; Tverdohleb, N V; Knyazev, R A; Polyakov, L M

    2015-11-01

    Production of recombinant human apolipoprotein A-I (apoA-I) in E. coli cells is described and its biological properties are compared with those of natural protein. Recombinant apoA-I was isolated as a chimeric polypeptide and then processed to a mature form apoA-I (rapo-I). We studied the ability of the resulting protein to penetrate into hepatocyte nuclei and regulate the rate of DNA biosynthesis in complex with estriol. Penetration of rapoA-I conjugated with FITC into hepatocyte nuclei was demonstrated. rapoA-I-estriol and apoA-I-estriol complexes induced similar increase in DNA biosynthesis rate in isolated hepatocytes, which confi rms functional similarity of the obtained recombinant mature protein (rapoA-I) and native human apoA-I.

  5. A complete backbone spectral assignment of human apolipoprotein AI on a 38 kDa preβHDL (Lp1-AI) particle

    SciTech Connect

    Ren, Xuefeng; Yang, Yunhuang; Neville, T.; Hoyt, David W.; Sparks, Daniel L.; Wang, Jianjun

    2007-06-12

    Apolipoprotein A-I (apoAI, 243-residues) is the major protein component of the high-density lipoprotein (HDL) that has been a hot subject of interests because of its anti-atherogenic properties. This important property of apoAI is related to its roles in reverse cholesterol transport pathway. Upon lipid-binding, apoAI undergoes conformational changes from lipid-free to several different HDL-associated states (1). These different conformational states regulate HDL formation, maturation and transportation. Two initial conformational states of apoAI are lipid-free apoAI and apoAI/preβHDL that recruit phospholipids and cholesterol to form HDL particles. In particular, lipid-free apoAI specifically binds to phospholipids to form lipid-poor apoAI, including apoAI/preβ-HDL (~37 kDa). As a unique class of lipid poor HDL, both in vitro and in vivo evidence demonstrates that apoAI/preβ-HDLs are the most effective acceptors specifically for free cholesterol in human plasma and serves as the precursor of HDL particles (2). Here we report a complete backbone spectral assignment of human apoAI/preβHDL. Secondary structure prediction using backbone NMR parameters indicates that apoAI/preβHDL displays a two-domain structure: the N-terminal four helix-bundle domain (residues 1-186) and the C-terminal flexible domain (residues 187-243). A structure of apoAI/preβ-HDL is the first lipid-associated structure of apoAI and is critical for us to understand how apoAI recruits cholesterol to initialize HDL formation. BMRB deposit with accession number: 15093.

  6. Expression of human apolipoprotein A-I in transgenic mice results in reduced plasma levels of murine apolipoprotein A-I and the appearance of two new high density lipoprotein size subclasses.

    PubMed

    Rubin, E M; Ishida, B Y; Clift, S M; Krauss, R M

    1991-01-15

    In Western societies high density lipoprotein (HDL) levels correlate inversely with the risk for coronary heart disease. The primary protein component of both human and mouse HDL is apolipoprotein A-I (apoAI), which comprises greater than 70% of HDL protein and 30% of HDL mass. Human HDLs include particles of several distinct size subpopulations, whereas HDLs from inbred C57BL/6 mice contain a single population of particles. To study the regulation of apoAI expression and its role in HDL assembly, we created transgenic C57BL/6 mice containing the human apoAI gene. Two independent lines of transgenic mice with approximately twice the normal plasma levels of total apoAI were studied. The level of mouse apoAI is reduced greater than 4-fold in both transgenic lines, comprising only 4% of total plasma apoAI levels in one transgenic line and 13% in the other. We demonstrate that the mechanism responsible for the decrease in mouse apoAI is posttranscriptional. Parallel to the replacement of mouse with human apoAI, the single HDL species normally present in the plasma of C57BL/6 is replaced by two HDL subclasses similar in size to human HDL2b and HDL3a. The changes in murine apolipoprotein levels and HDL subclass size are inherited by all transgenic offspring of the two founder animals. These results suggest a dominant role of apoAI in determining the HDL particle size distribution and a mechanism involving expression of human apoAI transgenes that alters the plasma levels of mouse apoAI.

  7. Inhibition of early atherogenesis in transgenic mice by human apolipoprotein AI.

    PubMed

    Rubin, E M; Krauss, R M; Spangler, E A; Verstuyft, J G; Clift, S M

    1991-09-19

    Epidemiological surveys have identified a strong inverse relationship between the amount in the plasma of high density lipoproteins (HDL), apolipoprotein AI (ApoA-I), the major protein component of HDL, and the risk for atherosclerosis in humans. It is not known if this relationship arises from a direct antiatherogenic effect of these plasma components or if it is the result of other factors also associated with increases in ApoA-I and HDL levels. Because some strains of mice are susceptible to diet-induced formation of preatherosclerotic fatty streak lesions, and because of available techniques for the genetic manipulation of this organism, the murine system offers a unique setting in which to investigate the process of early atherogenesis. To test the hypothesis that induction of a high plasma concentration of ApoA-I and HDL would inhibit this process, we studied the effects of atherogenic diets on transgenic mice expressing high amounts of human ApoA-I. We report that transgenic mice with high plasma ApoA-I and HDL levels were significantly protected from the development of fatty streak lesions.

  8. Human Apolipoprotein A-I Natural Variants: Molecular Mechanisms Underlying Amyloidogenic Propensity

    PubMed Central

    Ramella, Nahuel A.; Schinella, Guillermo R.; Ferreira, Sergio T.; Prieto, Eduardo D.; Vela, María E.; Ríos, José Luis

    2012-01-01

    Human apolipoprotein A-I (apoA-I)-derived amyloidosis can present with either wild-type (Wt) protein deposits in atherosclerotic plaques or as a hereditary form in which apoA-I variants deposit causing multiple organ failure. More than 15 single amino acid replacement amyloidogenic apoA-I variants have been described, but the molecular mechanisms involved in amyloid-associated pathology remain largely unknown. Here, we have investigated by fluorescence and biochemical approaches the stabilities and propensities to aggregate of two disease-associated apoA-I variants, apoA-IGly26Arg, associated with polyneuropathy and kidney dysfunction, and apoA-ILys107-0, implicated in amyloidosis in severe atherosclerosis. Results showed that both variants share common structural properties including decreased stability compared to Wt apoA-I and a more flexible structure that gives rise to formation of partially folded states. Interestingly, however, distinct features appear to determine their pathogenic mechanisms. ApoA-ILys107-0 has an increased propensity to aggregate at physiological pH and in a pro-inflammatory microenvironment than Wt apoA-I, whereas apoA-IGly26Arg elicited macrophage activation, thus stimulating local chronic inflammation. Our results strongly suggest that some natural mutations in apoA-I variants elicit protein tendency to aggregate, but in addition the specific interaction of different variants with macrophages may contribute to cellular stress and toxicity in hereditary amyloidosis. PMID:22952757

  9. The Conformation of Lipid-Free Human Apolipoprotein A-I in Solution

    PubMed Central

    Pollard, Ricquita D.; Fulp, Brian; Samuel, Michael P.; Sorci-Thomas, Mary G.; Thomas, Michael J.

    2014-01-01

    Apolipoprotein AI (apoA-I) is the principal acceptor of lipids from ATP-binding cassette transporter A1, a process that yields nascent high density lipoproteins. Analysis of lipidated apoA-I conformation yields a belt or twisted belt in which two strands of apoA-I lie antiparallel to one another. In contrast, biophysical studies have suggested that a part of lipid-free apoA-I was arranged in a 4-helix bundle. To understand how lipid-free apoA-I opens from a bundle to a belt while accepting lipid it was necessary to have a more refined model for the conformation of lipid-free apoA-I. This study reports the conformation of lipid-free human apoA-I using lysine-to-lysine chemical cross-linking in conjunction with disulfide cross-linking achieved using selective cysteine mutations. After proteolysis cross-linked peptides were verified by sequencing using tandem mass spectrometry. The resulting structure is compact with roughly 4 helical regions, amino acids 44 through 186, bundled together. C- and N-terminal ends, amino acids 1-43 and 187-243, respectively, are folded such that they lie close to one another. An unusual feature of the molecule is the high degree of connectivity of lysine40 with 6 other lysines, lysines that are close, e.g., lysine59, to distant lysines, e.g., lysine239, that are at the opposite end of the primary sequence. These results are compared and contrasted with other reported conformations for lipid-free human apoA-I and an NMR study of mouse apoA-I. PMID:24308268

  10. Differential regulation of human apolipoprotein AI and high-density lipoprotein by fenofibrate in hapoAI and hapoAI-CIII-AIV transgenic mice.

    PubMed

    Srivastava, Rai Ajit K; He, Shirley; Newton, Roger S

    2011-02-01

    Fenofibrate, a PPAR-α agonist, lowers triglycerides (TG) and raises high-density lipoproteins (HDL-C) in humans. While fenofibrate is very effective in lowering TG, it does not raise HDL-C in humans to the same extent as seen in human apoAI transgenic (hAI-Tg) mice. We studied the mechanism of this discordance using the following compounds as tools: cholic acid that down-regulates human apoAI, and fenofibrate, that elevates hapoAI and HDL-C in hAI-Tg mice. We hypothesized that additional sequences, including apoCIII and AIV genes on chromosome 11, not present in the hapoAI transgene may be responsible for the dampened effect of fibrates on HDL-C seen in humans. For this, hAI-Tg mice with 11kb DNA segment and hapoAI-CIII-AIV-Tg mice with 33kb DNA segment harboring apoCIII and AIV genes were employed. These mice were treated with fenofibrate and cholic acid. Fenofibrate increased apoAI and HDL-C levels, and HDL size in the apoAI-Tg mice via up-regulation of the hapoAI mRNA and increased activity and mRNA of PLTP, respectively. Consistent with earlier findings, cholic acid showed similar effects of lowering HDL-C, and elevating LDL-C in hAI-Tg mice as well as in the hAI-CIII-AIV-Tg mice. Fenofibrate decreased TG and increased HDL size in hAI-CIII-AIV-Tg mice as well, but surprisingly, did not elevate serum levels of hapoAI or hepatic AI mRNA, suggesting that additional sequences not present in the hapoAI transgene (11kb) may be partly responsible for the dampened effect on HDL-C seen in hAI-CIII-AIV-Tg mice. Since hAI-CIII-AIV-Tg mouse mimics fenofibrate effects seen in humans, this transgenic mouse could serve as a better predictive model for screening HDL-C raising compounds.

  11. Effects of red grape juice consumption on high density lipoprotein-cholesterol, apolipoprotein AI, apolipoprotein B and homocysteine in healthy human volunteers.

    PubMed

    Khadem-Ansari, Mohammad H; Rasmi, Yousef; Ramezani, Fatemeh

    2010-01-01

    It has suggested that grape juice consumption has lipid- lowering effect and it is associated with a decreased risk of heart disease. We aimed to evaluate the effects of red grape juice (RGj) consumption on high density lipoprotein-cholesterol (HDL-C), apolipoprotein AI (apoAI), apolipoprotein B (apoB) and homocysteine (Hcy) levels in healthy human volunteers. Twenty six healthy and nonsmoking males, aged between 25-60 years, who were under no medication asked to consume 150 ml of RGj twice per day for one month. Serum HDL-C, apoAI, apoB and plasma Hcy levels were measured before and after one month RGj consumption. HDL-C levels after RGj consumption were significantly higher than the corresponding levels before the RGj consumption (41.44 ± 4.50 and 44.37 ± 4.30 mg/dl; P<0.0001). Also, apoB was significantly increased after RGj consumption (149.0 ± 22.35 and 157.19 ± 18.60 mg/dl; P<0.002). But apoAI levels were not changed significantly before and after of RGj consumption (154.27 ± 21.55 and 155.35 ± 21.07 mg/dl; P>0.05). Hcy levels were decreased after RGj consumption (7.70 ± 2.80 and 6.20 ± 2.30 µmol/l; P<0.001). The present study demonstrates that RGj consumption can significantly increase serum HDL-C levels and decrease Hcy levels. These findings may have important implications for the prevention of atherosclerosis in healthy individuals. PMID:21633724

  12. High yield of recombinant human Apolipoprotein A-I expressed in Pichia pastoris by using mixed-mode chromatography.

    PubMed

    Narasimhan Janakiraman, Vignesh; Noubhani, Abdelmajid; Venkataraman, Krishnan; Vijayalakshmi, Mookambeswaran; Santarelli, Xavier

    2016-01-01

    A vast majority of the cardioprotective properties exhibited by High-Density Lipoprotein (HDL) is mediated by its major protein component Apolipoprotein A-I (ApoA1). In order to develop a simplified bioprocess for producing recombinant human Apolipoprotein A-I (rhApoA1) in its near-native form, rhApoA1was expressed without the use of an affinity tag in view of its potential therapeutic applications. Expressed in Pichia pastoris at expression levels of 58.2 mg ApoA1 per litre of culture in a reproducible manner, the target protein was purified by mixed-mode chromatography using Capto™ MMC ligand with a purity and recovery of 84% and 68%, respectively. ApoA1 purification was scaled up to Mixed-mode Expanded Bed Adsorption chromatography to establish an 'on-line' process for the efficient capture of rhApoA1 directly from the P. pastoris expression broth. A polishing step using anion exchange chromatography enabled the recovery of ApoA1 up to 96% purity. Purified ApoA1 was identified and verified by RPLC-ESI-Q-TOF mass spectrometry. This two-step process would reduce processing times and therefore costs in comparison to the twelve-step procedure currently used for recovering rhApoA1 from P. pastoris.

  13. Effect of TNF{alpha} on activities of different promoters of human apolipoprotein A-I gene

    SciTech Connect

    Orlov, Sergey V.; Mogilenko, Denis A.; Shavva, Vladimir S.; Dizhe, Ella B.; Ignatovich, Irina A.; Perevozchikov, Andrej P.

    2010-07-23

    Research highlights: {yields} TNF{alpha} stimulates the distal alternative promoter of human apoA-I gene. {yields} TNF{alpha} acts by weakening of promoter competition within apoA-I gene (promoter switching). {yields} MEK1/2 and nuclear receptors PPAR{alpha} and LXRs take part in apoA-I promoter switching. -- Abstract: Human apolipoprotein A-I (ApoA-I) is a major structural and functional protein component of high-density lipoproteins. The expression of the apolipoprotein A-I gene (apoA-I) in hepatocytes is repressed by pro-inflammatory cytokines such as IL-1{beta} and TNF{alpha}. Recently, two novel additional (alternative) promoters for human apoA-I gene have been identified. Nothing is known about the role of alternative promoters in TNF{alpha}-mediated downregulation of apoA-I gene. In this article we report for the first time about the different effects of TNF{alpha} on two alternative promoters of human apoA-I gene. Stimulation of HepG2 cells by TNF{alpha} leads to activation of the distal alternative apoA-I promoter and downregulation of the proximal alternative and the canonical apoA-I promoters. This effect is mediated by weakening of the promoter competition within human apoA-I 5'-regulatory region (apoA-I promoter switching) in the cells treated by TNF{alpha}. The MEK1/2-ERK1/2 cascade and nuclear receptors PPAR{alpha} and LXRs are important for TNF{alpha}-mediated apoA-I promoter switching.

  14. High-Density Lipoprotein Biogenesis: Defining the Domains Involved in Human Apolipoprotein A-I Lipidation.

    PubMed

    Pollard, Ricquita D; Fulp, Brian; Sorci-Thomas, Mary G; Thomas, Michael J

    2016-09-01

    The first step in removing cholesterol from a cell is the ATP-binding cassette transporter 1 (ABCA1)-driven transfer of cholesterol to lipid-free or lipid-poor apolipoprotein A-I (apoA-I), which yields cholesterol-rich nascent high-density lipoprotein (nHDL) that then matures in plasma to spherical, cholesteryl ester-rich HDL. However, lipid-free apoA-I has a three-dimensional (3D) conformation that is significantly different from that of lipidated apoA-I on nHDL. By comparing the lipid-free apoA-I 3D conformation of apoA-I to that of 9-14 nm diameter nHDL, we formulated the hypothetical helical domain transitions that might drive particle formation. To test the hypothesis, ten apoA-I mutants were prepared that contained two strategically placed cysteines several of which could form intramolecular disulfide bonds and others that could not form these bonds. Mass spectrometry was used to identify amino acid sequence and intramolecular disulfide bond formation. Recombinant HDL (rHDL) formation was assessed with this group of apoA-I mutants. ABCA1-driven nHDL formation was measured in four mutants and wild-type apoA-I. The mutants contained cysteine substitutions in one of three regions: the N-terminus, amino acids 34 and 55 (E34C to S55C), central domain amino acids 104 and 162 (F104C to H162C), and the C-terminus, amino acids 200 and 233 (L200C to L233C). Mutants were studied in the locked form, with an intramolecular disulfide bond present, or unlocked form, with the cysteine thiol blocked by alkylation. Only small amounts of rHDL or nHDL were formed upon locking the central domain. We conclude that both the N- and C-terminal ends assist in the initial steps in lipid acquisition, but that opening of the central domain was essential for particle formation.

  15. Amyloidogenic propensity of a natural variant of human apolipoprotein A-I: stability and interaction with ligands.

    PubMed

    Rosú, Silvana A; Rimoldi, Omar J; Prieto, Eduardo D; Curto, Lucrecia M; Delfino, José M; Ramella, Nahuel A; Tricerri, M Alejandra

    2015-01-01

    A number of naturally occurring mutations of human apolipoprotein A-I (apoA-I) have been associated with hereditary amyloidoses. The molecular mechanisms involved in amyloid-associated pathology remain largely unknown. Here we examined the effects of the Arg173Pro point mutation in apoA-I on the structure, stability, and aggregation propensity, as well as on the ability to bind to putative ligands. Our results indicate that the mutation induces a drastic loss of stability, and a lower efficiency to bind to phospholipid vesicles at physiological pH, which could determine the observed higher tendency to aggregate as pro-amyloidogenic complexes. Incubation under acidic conditions does not seem to induce significant desestabilization or aggregation tendency, neither does it contribute to the binding of the mutant to sodium dodecyl sulfate. While the binding to this detergent is higher for the mutant as compared to wt apoA-I, the interaction of the Arg173Pro variant with heparin depends on pH, being lower at pH 5.0 and higher than wt under physiological pH conditions. We suggest that binding to ligands as heparin or other glycosaminoglycans could be key events tuning the fine details of the interaction of apoA-I variants with the micro-environment, and probably eliciting the toxicity of these variants in hereditary amyloidoses. PMID:25950566

  16. Amyloidogenic Propensity of a Natural Variant of Human Apolipoprotein A-I: Stability and Interaction with Ligands

    PubMed Central

    Rosú, Silvana A.; Rimoldi, Omar J.; Prieto, Eduardo D.; Curto, Lucrecia M.; Delfino, José M.

    2015-01-01

    A number of naturally occurring mutations of human apolipoprotein A-I (apoA-I) have been associated with hereditary amyloidoses. The molecular mechanisms involved in amyloid-associated pathology remain largely unknown. Here we examined the effects of the Arg173Pro point mutation in apoA-I on the structure, stability, and aggregation propensity, as well as on the ability to bind to putative ligands. Our results indicate that the mutation induces a drastic loss of stability, and a lower efficiency to bind to phospholipid vesicles at physiological pH, which could determine the observed higher tendency to aggregate as pro-amyloidogenic complexes. Incubation under acidic conditions does not seem to induce significant desestabilization or aggregation tendency, neither does it contribute to the binding of the mutant to sodium dodecyl sulfate. While the binding to this detergent is higher for the mutant as compared to wt apoA-I, the interaction of the Arg173Pro variant with heparin depends on pH, being lower at pH 5.0 and higher than wt under physiological pH conditions. We suggest that binding to ligands as heparin or other glycosaminoglycans could be key events tuning the fine details of the interaction of apoA-I variants with the micro-environment, and probably eliciting the toxicity of these variants in hereditary amyloidoses. PMID:25950566

  17. Definition of human apolipoprotein A-I epitopes recognized by autoantibodies present in patients with cardiovascular diseases.

    PubMed

    Teixeira, Priscila Camillo; Ducret, Axel; Ferber, Philippe; Gaertner, Hubert; Hartley, Oliver; Pagano, Sabrina; Butterfield, Michelle; Langen, Hanno; Vuilleumier, Nicolas; Cutler, Paul

    2014-10-10

    Autoantibodies to apolipoprotein A-I (anti-apoA-I IgG) have been shown to be both markers and mediators of cardiovascular disease, promoting atherogenesis and unstable atherosclerotic plaque. Previous studies have shown that high levels of anti-apoA-I IgGs are independently associated with major adverse cardiovascular events in patients with myocardial infarction. Autoantibody responses to apoA-I can be polyclonal and it is likely that more than one epitope may exist. To identify the specific immunoreactive peptides in apoA-I, we have developed a set of methodologies and procedures to isolate, purify, and identify novel apoA-I endogenous epitopes. First, we generated high purity apoA-I from human plasma, using thiophilic interaction chromatography followed by enzymatic digestion specifically at lysine or arginine residues. Immunoreactivity to the different peptides generated was tested by ELISA using serum obtained from patients with acute myocardial infarction and high titers of autoantibodies to native apoA-I. The immunoreactive peptides were further sequenced by mass spectrometry. Our approach successfully identified two novel immunoreactive peptides, recognized by autoantibodies from patients suffering from myocardial infarction, who contain a high titer of anti-apoA-I IgG. The discovery of these epitopes may open innovative prognostic and therapeutic opportunities potentially suitable to improve current cardiovascular risk stratification.

  18. Cholesterol efflux potential of sera from mice expressing human cholesteryl ester transfer protein and/or human apolipoprotein AI.

    PubMed Central

    Atger, V; de la Llera Moya, M; Bamberger, M; Francone, O; Cosgrove, P; Tall, A; Walsh, A; Moatti, N; Rothblat, G

    1995-01-01

    The ability of whole serum to promote cell cholesterol efflux and the relationships between apoprotein and lipoprotein components of human serum efflux have been investigated previously (de la Llera Moya, M., V. Atger, J.L. Paul, N. Fournier, N. Moatti, P. Giral, K.E. Friday, and G.H. Rothblat. 1994. Arterioscler. Thromb. 14:1056-1065). We have now used this experimental system to study the selective effects of two human lipoprotein-related proteins, apoprotein AI (apo AI) and cholesteryl ester transfer protein (CETP) on cell cholesterol efflux, when these proteins are expressed in transgenic mice. The percent efflux values for cholesterol released in 4 h from Fu5AH donor cells to 5% sera from the different groups of mice were in the order: background = human apo AI transgenic (HuAITg) > human CETP transgenic (HuCETPTg) > human apo AI and CETP transgenic (HuAICETPTg) >> apo AI knockout mice. In each group of mice a strong, positive correlation (r2 ranging from 0.64 to 0.76) was found between efflux and HDL cholesterol concentrations. The slopes of these regression lines differed between groups of mice, indicating that the cholesterol acceptor efficiencies of the sera differed among groups. These differences in relative efficiencies can explain why cholesterol efflux was not proportional to the different HDL levels in the various groups of mice. We can conclude that: (a) HDL particles from HuAITg mice are less efficient as cholesterol acceptors than HDL from the background mice; (b) despite a lower average efflux due to lower HDL cholesterol concentrations, HDL particles are more efficient in the HuCETPTg mice than in the background mice; and (c) the coexpression of both human apo AI and CETP improves the efficiency of HDL particles in the HuAICETPTg mice when compared with the HuAITg mice. We also demonstrated that the esterification of the free cholesterol released from the cells by lecithin cholesterol acyltransferase in the serum was reduced in the HuAITg and AI

  19. Human apolipoprotein A-I is associated with dengue virus and enhances virus infection through SR-BI.

    PubMed

    Li, Yujia; Kakinami, Cherie; Li, Qi; Yang, Baojun; Li, Hongwei

    2013-01-01

    Diseases caused by dengue virus (DV) infection vary in severity, with symptoms ranging from mild fever to life threatening dengue hemorrhage fever (DHF) and dengue shock syndrome (DSS). Clinical studies have shown that significant decrease in the level of lipoproteins is correlated with severe illness in DHF/DSS patients. Available evidence also indicates that lipoproteins including high-density lipoprotein (HDL) and low-density lipoprotein (LDL) are able to facilitate cell entry of HCV or other flaviviruses via corresponding lipoprotein receptors. In this study, we found that pre-incubation of DV with human serum leads to an enhanced DV infectivity in various types of cells. Such enhancement could be due to interactions between serum components and DV particles. Through co-immunoprecipitation we revealed that apolipoprotein A-I (ApoA-I), the major protein component in HDL, is associated with DV particles and is able to promote DV infection. Based on that observation, we further found that siRNA knockdown of the scavenger receptor class B type I (SR-BI), the cell receptor of ApoA-I, abolished the activity of ApoA-I in enhancement of DV infection. This suggests that ApoA-I bridges DV particles and cell receptor SR-BI and facilitates entry of DV into cells. FACS analysis of cell surface dengue antigen after virus absorption further confirmed that ApoA-I enhances DV infection via promoting initial attachment of the virus to cells. These findings illustrate a novel entry route of DV into cells, which may provide insights into the functional importance of lipoproteins in dengue pathogenesis. PMID:23894648

  20. Expression of human hepatic lipase negatively impacts apolipoprotein A-I production in primary hepatocytes from Lipc-null mice.

    PubMed

    Bamji-Mirza, Michelle; Zhang, Wandong; Yao, Zemin

    2014-05-01

    This study aimed to examine whether expression of human hepatic lipase (hHL) exerted an intracellular effect on hepatic production of apolipoprotein (apo) A-I. The levels of secreted and cell-associated apoA-I were contrasted between primary hepatocytes isolated from Lipc-null and C57BL/6 mice, and between Lipc-null hepatocytes transfected with either hHL-encoding or control adenovirus. An HSPG-binding deficient hHL protein (hHLmt) was used to determine the impact of cell surface binding on HL action. Accumulation of apoA-I in conditioned media of primary hepatocytes isolated from Lipc-null mice was increased as compared to that from C57BL/6 mice. Metabolic labeling experiments showed that secretion of (35)S-apoA-I from Lipc-null cells was significantly higher than that from C57BL/6 cells. Expression of hHL in Lipc-null hepatocytes, through adenovirus-mediated gene transfer, resulted in decreased synthesis and secretion of (35)S-apoA-I, but not (35)S-apoE, as compared with cells transfected with control adenovirus. Expression of HSPG-binding deficient hHLmt in Lipc-null cells also exerted an inhibitory effect on apoA-I production, even though hHLmt displayed impaired exit from the endoplasmic reticulum as compared with hHL. Subcellular fractionation revealed that expression of hHL or hHLmt led to increased microsome-association of apoA-I relative to non-transfected control. Expression of hHL negatively impacts hepatic production of apoA-I.

  1. Combined N- and C-terminal truncation of human apolipoprotein A-I yields a folded, functional central domain.

    PubMed

    Beckstead, Jennifer A; Block, Brian L; Bielicki, John K; Kay, Cyril M; Oda, Michael N; Ryan, Robert O

    2005-03-22

    A combined N- and C-terminal truncation variant of human apolipoprotein A-I (apoA-I) was designed, expressed in Escherichia coli, isolated, and characterized. Hydrodynamic experiments yielded a weight average molecular weight of 34000, indicating apoA-I-(44-186) exists in solution predominantly as a dimer. An axial ratio of 4.2 was calculated for the dimer based on sedimentation velocity experiments. Far-UV circular dichroism spectroscopy of apoA-I-(44-186) in buffer indicated the presence of 65% alpha-helix secondary structure. Guanidine hydrochloride denaturation experiments yielded a transition midpoint of 0.5 M for apoA-I-(44-186). ApoA-I-(44-186) induced solubilization of dimyristoylphosphatidylcholine vesicles at a rate comparable to that of full-length apoA-I, displayed lipoprotein binding ability, and was an acceptor of ABCA1-mediated cholesterol efflux from cultured macrophages. Fluorescence quenching studies with KI indicate that the three Trp residues in apoA-I-(44-186) are shielded from the aqueous environment. Taken together, the data indicate that lipid-free apoA-I-(44-186) adopts a folded conformation in solution that possesses lipid binding capability. The central region of apoA-I appears to adopt a globular amphipathic alpha-helix bundle organization that is stabilized by intramolecular and/or intermolecular helix-helix interactions. Lipid association likely results in a conformational adaptation wherein helix-helix contacts are substituted for helix-lipid interactions.

  2. Comparison of deuterated leucine, valine, and lysine in the measurement of human apolipoprotein A-I and B-100 kinetics

    SciTech Connect

    Lichtenstein, A.H.; Cohn, J.S.; Hachey, D.L.; Millar, J.S.; Ordovas, J.M.; Schaefer, E.J. )

    1990-09-01

    The production rates of apolipoprotein (apo)B-100 in very low density lipoprotein and in low density lipoprotein and apolipoprotein A-I in high density lipoprotein were determined using a primed-constant infusion of (5,5,5,-2H3)leucine, (4,4,4,-2H3)valine, and (6,6-2H2,1,2-13C2)lysine. The three stable isotope-labeled amino acids were administered simultaneously to determine whether absolute production rates calculated using a stochastic model were independent of the tracer species utilized. Three normolipidemic adult males were studied in the constantly fed state over a 15-h period. The absolute production rates of very low density lipoprotein apoB-100 were 11.4 +/- 5.8 (leucine), 11.2 +/- 6.8 (valine), and 11.1 +/- 5.4 (lysine) mg per kg per day (mean +/- SDM). The absolute production rates for low density lipoprotein apoB-100 were 8.0 +/- 4.7 (leucine), 7.5 +/- 3.8 (valine), and 7.5 +/- 4.2 (lysine) mg per kg per day. The absolute production rates for high density lipoprotein apoA-I were 9.7 +/- 0.2 (leucine), 9.4 +/- 1.7 (valine), and 9.1 +/- 1.3 (lysine) mg per kg per day. There were no statistically significant differences in absolute synthetic rates of the three apolipoproteins when the plateau isotopic enrichment values of very low density lipoprotein apoB-100 were used to define the isotopic enrichment of the intracellular precursor pool. Our data indicate that deuterated leucine, valine, or lysine provided similar results when used for the determination of apoA-I and apoB-100 absolute production rates within plasma lipoproteins as part of a primed-constant infusion protocol.

  3. Expression of the human apolipoprotein A-I gene in transgenic mice alters high density lipoprotein (HDL) particle size distribution and diminishes selective uptake of HDL cholesteryl esters

    SciTech Connect

    Chajekshaul, T.; Hayek, T.; Walsh, A.; Breslow, J.L. )

    1991-08-01

    Transgenic mice carrying the human apolipoprotein (apo) A-I gene (HuAITg mice) were used to examine the effects of overexpression of the human gene on high density lipoprotein (HDL) particle size distribution and metabolism. On a chow diet, control mice had HDL cholesterol and apo A-I levels of 49 {plus minus} 2 and 137 {plus minus} 12 mg/dl of plasma, respectively. HuAITg mice had HDL cholesterol, human apo A-I, and mouse apo A-I levels of 88 {plus minus} 2, 255 {plus minus} 19, and 16 {plus minus} 2 mg/dl, respectively. Nondenaturing gradient gel electrophoresis revealed control mouse plasma HDL to be primarily monodisperse with a particle diameter of 10.2 nm, whereas HuAITg mouse plasma HDL was polydisperse with particles of diameter 11.4, 10.2, and 8.7 nm, which correspond in size to human HDL1, HDL2, and HDL3, respectively. In vivo turnover studies of HDL labeled with (3H)cholesteryl linoleyl ether and 125I-apo A-I were performed. In control animals, the fractional catabolic rate (FCR) for HDL cholesteryl ester was significantly more than the apo A-I FCR. In the HuAITg mice, the HDL cholesteryl ester FCR was the same as the apo A-I FCR. There were no significant differences between control and HuAITg animals in the sites of tissue removal of HDL cholesteryl ester, with the liver extracting most of the injected radioactivity. Control and HuAITg animals had comparable liver and intestinal cholesterol synthesis and LDL FCR. In conclusion, HuAITg mice have principally human and not mouse apo A-I in their plasma. This apparently causes a change in HDL particle size distribution in the transgenic mice to one resembling the human pattern. The replacement of mouse by human apo A-I also apparently causes the loss of the selective uptake pathway of HDL cholesteryl esters present in control mice.

  4. Apolipoprotein A-I: A Molecule of Diverse Function.

    PubMed

    Mangaraj, Manaswini; Nanda, Rachita; Panda, Suchismita

    2016-07-01

    Apolipoprotein A-I (apo A-I) an indispensable component and a major structural protein of high-density lipoprotein (HDL), plays a vital role in reverse cholesterol transport and cellular cholesterol homeostasis since its identification. Its multifunctional role in immunity, inflammation, apoptosis, viral, bacterial infection etc. has crossed its boundary of its potential of protecting cardiovascular system and lowering cardiovascular disease risk, attributing HDL to be known as a protective fat removal particle. Its structural homology with prostacyclin stabilization factor has contributed to its anti-clotting and anti-aggregatory effect on platelet which has potentiated its cardio-protective role as well as its therapeutic efficacy against Alzheimer's disease. The binding affinity and neutralising action against endotoxin lipopolysaccharide, reduces the toxic manifestations of septic shock. As a negative acute phase protein, it blocks T-cell signalling of macrophages. However the recently identified anti-tumor activity of apo A-I has been highlighted in various models of melanoma, lung cancer, ovarian cancer, lymphoblastic leukaemia, gastric as well as pancreatic cancers. These cancer fighting effects are directed towards regression of tumor size and distant metastasis by its immuno modulatory activity as well as its clearing effect on serum lysophospholipids. This lowering effect on lysophospholipid concentration is utilized by apo A-I mimetic peptides to be used in retarding tumor cell proliferation and as a potential cancer therapeutic agent. Not only that, it inhibits the tumor associated neo-angiogenesis as well as brings down the matrix degrading enzymes associated with tumor metastasis. However this efficient therapeutic potential of apo A-I as an anti tumor agent awaits further future experimental studies in humans. PMID:27382195

  5. Apolipoprotein A-I: A Molecule of Diverse Function.

    PubMed

    Mangaraj, Manaswini; Nanda, Rachita; Panda, Suchismita

    2016-07-01

    Apolipoprotein A-I (apo A-I) an indispensable component and a major structural protein of high-density lipoprotein (HDL), plays a vital role in reverse cholesterol transport and cellular cholesterol homeostasis since its identification. Its multifunctional role in immunity, inflammation, apoptosis, viral, bacterial infection etc. has crossed its boundary of its potential of protecting cardiovascular system and lowering cardiovascular disease risk, attributing HDL to be known as a protective fat removal particle. Its structural homology with prostacyclin stabilization factor has contributed to its anti-clotting and anti-aggregatory effect on platelet which has potentiated its cardio-protective role as well as its therapeutic efficacy against Alzheimer's disease. The binding affinity and neutralising action against endotoxin lipopolysaccharide, reduces the toxic manifestations of septic shock. As a negative acute phase protein, it blocks T-cell signalling of macrophages. However the recently identified anti-tumor activity of apo A-I has been highlighted in various models of melanoma, lung cancer, ovarian cancer, lymphoblastic leukaemia, gastric as well as pancreatic cancers. These cancer fighting effects are directed towards regression of tumor size and distant metastasis by its immuno modulatory activity as well as its clearing effect on serum lysophospholipids. This lowering effect on lysophospholipid concentration is utilized by apo A-I mimetic peptides to be used in retarding tumor cell proliferation and as a potential cancer therapeutic agent. Not only that, it inhibits the tumor associated neo-angiogenesis as well as brings down the matrix degrading enzymes associated with tumor metastasis. However this efficient therapeutic potential of apo A-I as an anti tumor agent awaits further future experimental studies in humans.

  6. A frameshift mutation in the human apolipoprotein A-I gene causes high density lipoprotein deficiency, partial lecithin: cholesterol-acyltransferase deficiency, and corneal opacities.

    PubMed Central

    Funke, H; von Eckardstein, A; Pritchard, P H; Karas, M; Albers, J J; Assmann, G

    1991-01-01

    Epidemiologic data of recent years have identified an important role of HDL deficiency in the etiology of atherosclerosis. Biochemical data suggest that some of these deficiencies may be a consequence of defects in the structural genes of HDL apolipoproteins or of plasma enzymes that modify HDL. We analyzed the genetic defect in a 42-yr-old patient suffering from corneal opacities and complete absence of HDL cholesterol but not of coronary artery disease, thus clinically resembling fish eye disease. The observation of an abnormal immunoblot banding pattern of apolipoprotein A-I (apo A-I) and of reduced lecithin: cholesterol acyltransferase (LCAT) activity in plasma led to sequence analysis of the genes for apo A-I and LCAT in this patient and his family. Direct sequencing of polymerase chain reaction amplified DNA segments containing the exons of the candidate genes, resulted in the identification of a frameshift mutation in apo A-I while the LCAT sequence was identical to the wild type. The apo A-I mutation was predictive for an extensive alteration of the COOH-terminal sequence of the encoded protein. Evidence for the release of this mutant protein into the plasma compartment and for the absence of normal apo A-I was derived from ultraviolet laser desorption/ionization mass spectrometry analysis. Our results suggest that a defective apo A-I is the causative defect in this case of HDL deficiency with corneal opacities. Images PMID:1898657

  7. A role for Apolipoprotein A-I in the pathogenesis of multiple sclerosis.

    PubMed

    Meyers, Lindsay; Groover, Chassidy J; Douglas, Joshua; Lee, Sangmin; Brand, David; Levin, Michael C; Gardner, Lidia A

    2014-12-15

    Apolipoprotein A1 (Apo A-I), the most abundant component of high-density lipoprotein (HDL), is an anti-inflammatory molecule, yet its potential role in the pathogenesis of multiple sclerosis (MS) has not been fully investigated. In this study, Western blot analyses of human plasma showed differential Apo A-I expression in healthy controls compared to MS patients. Further, primary progressive MS patients had less plasma Apo A-I than other forms of MS. Using experimental allergic encephalomyelitis (EAE) as a model for MS, Apo A-I deficient mice exhibited worse clinical disease and more neurodegeneration concurrent with increased levels of pro-inflammatory cytokines compared to wild-type animals. These data suggest that Apo A-I plays a role in the pathogenesis of EAE, a model for MS, creating the possibility for agents that increase Apo A-I levels as potential therapies for MS.

  8. Apolipoprotein AI mutation Arg-60 causes autosomal dominant amyloidosis.

    PubMed Central

    Soutar, A K; Hawkins, P N; Vigushin, D M; Tennent, G A; Booth, S E; Hutton, T; Nguyen, O; Totty, N F; Feest, T G; Hsuan, J J

    1992-01-01

    A mutation in the gene for apolipoprotein AI (apoAI) was identified in an English family with autosomal dominant non-neuropathic systemic amyloidosis. The plasma of all affected individuals contained a variant apoAI with one additional charge, as well as normal apoAI. The propositus was heterozygous; the coding region of his apoAI gene contained both the normal sequence and a single-base substitution changing the codon for residue 60 of the mature protein from CTG (leucine) to CGG (arginine). Allele-specific oligonucleotide hybridization showed that the other affected individuals were also heterozygotes and that there was concordance of the mutant allele with the presence of variant plasma apoAI. Amyloid fibrils isolated from the spleen of the propositus consisted of proteins that ran as a doublet with an apparent mass of approximately 10 kDa in SDS/PAGE and a trace band at 28 kDa. Electrospray mass spectrometry of the purified 10-kDa material revealed components with mass corresponding to the N-terminal 88, 92, 93, and 94 residues of apoAI each with substitution of arginine for leucine. These observations were confirmed by direct protein sequencing and laser desorption time-of-flight mass analysis. No material with the normal apoAI sequence was detected. The trace band at 28 kDa yielded the N-terminal sequence of mature apoAI, indicating that intact or minimally degraded apoAI was also present in the fibril preparation. Discovery of this mutation and the detailed characterization of the apoAI fragments that form the amyloid fibrils open additional avenues for investigation of amyloidogenesis. Images PMID:1502149

  9. Apolipoprotein A-I variants. Naturally occurring substitutions of proline residues affect plasma concentration of apolipoprotein A-I.

    PubMed Central

    von Eckardstein, A; Funke, H; Henke, A; Altland, K; Benninghoven, A; Assmann, G

    1989-01-01

    Six unrelated families with genetically determined structural variants of apo A-I were found in the course of an electrophoretic screening program for apo A-I variants in dried blood samples of newborns. The following structural variations were identified by the combined use of HPLC, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and automated gas phase sequencing: Pro3----Arg (1x), Pro4----Arg (1x), and Pro165----Arg (4x). All variant carriers were heterozygous for their mutant of apo A-I. Subjects heterozygous for apo A-I(Pro165----Arg) (n = 12) were found to exhibit lower mean values for apo A-I (109 +/- 16 mg/dl) and HDL cholesterol (37 +/- 9 mg/dl) than unaffected family members (n = 9): 176 +/- 41 and 64 +/- 18 mg/dl, respectively (P less than 0.001). In 9 of 12 apo A-I(Pro165----Arg) variant carriers the concentrations of apo A-I were below the fifth percentile of sex-matched controls. By two-dimensional immunoelectrophoresis as well as by densitometry the relative concentration of the variant apo A-I in heterozygous carriers of apo A-I(Pro165----Arg) was determined to account for only 30% of the total plasma apo A-I mass instead of the expected 50%. Thus, the observed apo A-I deficiency may be largely a consequence of the decreased concentration of the variant apo A-I. In the case of the apo A-I(Pro3----Arg) mutant, densitometry of HDL apolipoproteins demonstrated a distinctly increased concentration of the variant proapo A-I relative to normal proapo A-I. This phenomenon was not observed in the apo A-I(Pro4----Arg) mutant or in other mutants. This suggests that the interspecies conserved proline residue in position 3 of mature apo A-I is functionally important for the regular enzymatic conversion of proapo A-I to mature apo A-I. Images PMID:2512329

  10. Emerging Roles of Apolipoprotein E and Apolipoprotein A-I in the Pathogenesis and Treatment of Lung Disease.

    PubMed

    Yao, Xianglan; Gordon, Elizabeth M; Figueroa, Debbie M; Barochia, Amisha V; Levine, Stewart J

    2016-08-01

    Emerging roles are being recognized increasingly for apolipoproteins in the pathogenesis and treatment of lung diseases on the basis of their ability to suppress inflammation, oxidative stress, and tissue remodeling, and to promote adaptive immunity and host defense. Apolipoproteins, such as apolipoprotein E (apoE) and apolipoprotein A-I (apoA-I), are important components of lipoprotein particles that facilitate the transport of cholesterol, triglycerides, and phospholipids between plasma and cells. ApoE-containing lipoprotein particles are internalized into cells by low-density lipoprotein receptors (LDLRs), whereas apoA-I can interact with the ATP-binding cassette subfamily A member 1 (ABCA1) transporter to efflux cholesterol and phospholipids out of cells. ApoE and apoA-I also mediate receptor-independent effects, such as binding to and neutralizing LPS. Both apoE and apoA-I are expressed by lung cells, which allows apoE/LDLR- and apoA-I/ABCA1-dependent pathways to modulate normal lung health and the pathogenesis of respiratory diseases, including asthma, acute lung injury, cancer, emphysema, pulmonary fibrosis, and pulmonary hypertension. Data from human studies and research using experimental murine model systems have shown that both apoE and apoA-I pathways play primarily protective roles in lung biology and respiratory disease. Furthermore, apolipoprotein mimetic peptides, corresponding to the LDLR-binding domain of apoE or the class A amphipathic α-helical structure of apoA-I, have antiinflammatory and antioxidant effects that attenuate the severity of lung disease in murine models. Thus, the development of inhaled apolipoprotein mimetic peptides as a novel treatment paradigm could represent a significant advance for patients with respiratory disease who do not respond to current therapies.

  11. Conformation and Lipid Binding of a C-Terminal (198-243) Peptide of Human Apolipoprotein A-I (apoA-I)†

    PubMed Central

    Zhu, Hongli L.; Atkinson, David

    2008-01-01

    Human apolipoprotein A-I (apoA-I) is the principle apolipoprotein of high-density lipoproteins that are critically involved in reverse cholesterol transport. The intrinsically flexibility of apoA-I has hindered studies of the structural and functional details of the protein. Our strategy is to study peptide models representing different regions of apoA-I. Our previous report on [1-44]apoA-I demonstrated that this N-terminal region is unstructured and folds into ~ 60% α-helix with a moderate lipid binding affinity. We now present details of the conformation and lipid interaction of a C-terminal 46 residue peptide, [198-243]apoA-I, encompassing putative helix repeats 10, 9 and the second half of repeat 8 from the C-terminus of apoA-I. Far ultraviolet circular dichroism spectra show that [198-243] apoA-I is also unfolded in aqueous solution. However, self-association induces ~ 50% α-helix in the peptide. The self-associated peptide exists mainly as a tetramer, as determined by native electrophoresis, cross-linking with glutaraldehyde and unfolding data from circular dichroism (CD) and differential scanning calorimetry (DSC). In the presence of a number of lipid mimicking detergents, above their CMC, ~ 60% α-helix was induced in the peptide. In contrast, SDS, an anionic lipid mimicking detergent, induced helical folding in the peptide at a concentration of ~ 0.003% (~ 100 μM), ~ 70 fold below its typical CMC (0.17–0.23% or 6–8 mM). Both monomeric and tetrameric peptide can solublize dimyristoyl phosphatidyl choline (DMPC) liposomes and fold into ~ 60% α-helix. Fractionation by density gradient ultracentrifugation and visualization by negative staining electromicroscopy, demonstrated that the peptide binds to DMPC with high affinity to form at least two sizes of relatively homogenous discoidal HDL-like particles depending on the initial lipid:peptide ratio. The characteristics (lipid:peptide w/w, diameter and density) of both complexes are similar to those of

  12. Site-specific Nitration of Apolipoprotein A-I at Tyrosine 166 Is Both Abundant within Human Atherosclerotic Plaque and Dysfunctional*

    PubMed Central

    DiDonato, Joseph A.; Aulak, Kulwant; Huang, Ying; Wagner, Matthew; Gerstenecker, Gary; Topbas, Celalettin; Gogonea, Valentin; DiDonato, Anthony J.; Tang, W. H. Wilson; Mehl, Ryan A.; Fox, Paul L.; Plow, Edward F.; Smith, Jonathan D.; Fisher, Edward A.; Hazen, Stanley L.

    2014-01-01

    We reported previously that apolipoprotein A-I (apoA-I) is oxidatively modified in the artery wall at tyrosine 166 (Tyr166), serving as a preferred site for post-translational modification through nitration. Recent studies, however, question the extent and functional importance of apoA-I Tyr166 nitration based upon studies of HDL-like particles recovered from atherosclerotic lesions. We developed a monoclonal antibody (mAb 4G11.2) that recognizes, in both free and HDL-bound forms, apoA-I harboring a 3-nitrotyrosine at position 166 apoA-I (NO2-Tyr166-apoA-I) to investigate the presence, distribution, and function of this modified apoA-I form in atherosclerotic and normal artery wall. We also developed recombinant apoA-I with site-specific 3-nitrotyrosine incorporation only at position 166 using an evolved orthogonal nitro-Tyr-aminoacyl-tRNA synthetase/tRNACUA pair for functional studies. Studies with mAb 4G11.2 showed that NO2-Tyr166-apoA-I was easily detected in atherosclerotic human coronary arteries and accounted for ∼8% of total apoA-I within the artery wall but was nearly undetectable (>100-fold less) in normal coronary arteries. Buoyant density ultracentrifugation analyses showed that NO2-Tyr166-apoA-I existed as a lipid-poor lipoprotein with <3% recovered within the HDL-like fraction (d = 1.063–1.21). NO2-Tyr166-apoA-I in plasma showed a similar distribution. Recovery of NO2-Tyr166-apoA-I using immobilized mAb 4G11.2 showed an apoA-I form with 88.1 ± 8.5% reduction in lecithin-cholesterol acyltransferase activity, a finding corroborated using a recombinant apoA-I specifically designed to include the unnatural amino acid exclusively at position 166. Thus, site-specific nitration of apoA-I at Tyr166 is an abundant modification within the artery wall that results in selective functional impairments. Plasma levels of this modified apoA-I form may provide insights into a pathophysiological process within the diseased artery wall. PMID:24558038

  13. Identification of Apolipoprotein A-I as a Retinoic Acid-binding Protein in the Eye.

    PubMed

    Summers, Jody A; Harper, Angelica R; Feasley, Christa L; Van-Der-Wel, Hanke; Byrum, Jennifer N; Hermann, Marcela; West, Christopher M

    2016-09-01

    All-trans-retinoic acid may be an important molecular signal in the postnatal control of eye size. The goal of this study was to identify retinoic acid-binding proteins secreted by the choroid and sclera during visually guided ocular growth. Following photoaffinity labeling with all-trans-[11,12-(3)H]retinoic acid, the most abundant labeled protein detected in the conditioned medium of choroid or sclera had an apparent Mr of 27,000 Da. Following purification and mass spectrometry, the Mr 27,000 band was identified as apolipoprotein A-I. Affinity capture of the radioactive Mr 27,000 band by anti-chick apolipoprotein A-I antibodies confirmed its identity as apolipoprotein A-I. Photoaffinity labeling and fluorescence quenching experiments demonstrated that binding of retinoic acid to apolipoprotein A-I is 1) concentration-dependent, 2) selective for all-trans-retinoic acid, and 3) requires the presence of apolipoprotein A-I-associated lipids for retinoid binding. Expression of apolipoprotein A-I mRNA and protein synthesis were markedly up-regulated in choroids of chick eyes during the recovery from induced myopia, and apolipoprotein A-I mRNA was significantly increased in choroids following retinoic acid treatment. Together, these data suggest that apolipoprotein A-I may participate in a regulatory feedback mechanism with retinoic acid to control the action of retinoic acid on ocular targets during postnatal ocular growth.

  14. Identification of Apolipoprotein A-I as a Retinoic Acid-binding Protein in the Eye.

    PubMed

    Summers, Jody A; Harper, Angelica R; Feasley, Christa L; Van-Der-Wel, Hanke; Byrum, Jennifer N; Hermann, Marcela; West, Christopher M

    2016-09-01

    All-trans-retinoic acid may be an important molecular signal in the postnatal control of eye size. The goal of this study was to identify retinoic acid-binding proteins secreted by the choroid and sclera during visually guided ocular growth. Following photoaffinity labeling with all-trans-[11,12-(3)H]retinoic acid, the most abundant labeled protein detected in the conditioned medium of choroid or sclera had an apparent Mr of 27,000 Da. Following purification and mass spectrometry, the Mr 27,000 band was identified as apolipoprotein A-I. Affinity capture of the radioactive Mr 27,000 band by anti-chick apolipoprotein A-I antibodies confirmed its identity as apolipoprotein A-I. Photoaffinity labeling and fluorescence quenching experiments demonstrated that binding of retinoic acid to apolipoprotein A-I is 1) concentration-dependent, 2) selective for all-trans-retinoic acid, and 3) requires the presence of apolipoprotein A-I-associated lipids for retinoid binding. Expression of apolipoprotein A-I mRNA and protein synthesis were markedly up-regulated in choroids of chick eyes during the recovery from induced myopia, and apolipoprotein A-I mRNA was significantly increased in choroids following retinoic acid treatment. Together, these data suggest that apolipoprotein A-I may participate in a regulatory feedback mechanism with retinoic acid to control the action of retinoic acid on ocular targets during postnatal ocular growth. PMID:27402828

  15. Hereditary apolipoprotein AI-associated renal amyloidosis: A diagnostic challenge.

    PubMed

    Samillán-Sosa, Kelly Del Rocío; Sención-Martínez, Gloria; Lopes-Martín, Vanessa; Martínez-González, Miguel Angel; Solé, Manel; Arostegui, Jose Luis; Mesa, Jose; García-Díaz, Juan de Dios; Rodríguez-Puyol, Diego; Martínez-Miguel, Patricia

    2015-01-01

    Hereditary renal amyloidosis is an autosomal dominant condition with considerable overlap with other amyloidosis types. Differential diagnosis is complicated, but is relevant for prognosis and treatment. We describe a patient with nephrotic syndrome and progressive renal failure, who had a mother with renal amiloidosis. Renal biopsy revealed amyloid deposits in glomerular space, with absence of light chains and protein AA. We suspected amyloidosis with fibrinogen A alpha chain deposits, which is the most frequent cause of hereditary amyloidosis in Europe, with a glomerular preferential affectation. However, the genetic study showed a novel mutation in apolipoprotein AI. On reviewing the biopsy of the patient's mother similar glomerular deposits were found, but there were significant deposits in the renal medulla as well, which is typical in APO AI amyloidosis. The diagnosis was confirmed by immunohistochemistry. Apo AI amyloidosis is characterized by slowly progressive renal disease and end-stage renal disease occurs aproximately 3 to 15 years from initial diagnosis. Renal transplantation offers an acceptable graft survival and in these patients with hepatorenal involvement simultaneous liver and kidney transplantation could be considered.

  16. DNA inversion within the apolipoproteins AI/CIII/AIV-encoding gene cluster of certain patients with premature atherosclerosis

    SciTech Connect

    Karathanasis, S.K.; Ferris, E.; Haddad, I.A.

    1987-10-01

    The genes coding for apolipoproteins (apo) AI, CIII, and AIV, designated APOA1, APOC3, and APOA4, respectively, are closely linked and tandemly organized in the long arm of the human chromosome 11. A DNA rearrangement involving the genes encoding apoAI and apoCIII in certain patients with premature atherosclerosis has been associated with deficiency of both apoAI and apoCIII in the plasma of these patients. Structural characterization of the genes for apoAI and apoCIII in one of these patients indicates that this rearrangement consists of a DNA inversion containing portions of the 3' ends of the apoAI and apoCIII genes, including the DNA region between these genes. The breakpoints of this DNA inversion are located within the fourth exon of the apoAI gene and the first intron of the apoCIII gene. Thus, this DNA inversion results in reciprocal fusion of the apoAI and apoCIII gene transcriptional units. Expression of these gene fusions in cultured mammalian cells results in stable mRNA transcripts with sequences representing fusions of the apoAI and apoCIII mRNAs. These results indicate that absence of transcripts with correct apoAI and apoCIII mRNA sequences causes apoAI and apoCIII deficiency in the plasma of these patients and suggest that these apolipoproteins are involved in cholesterol homeostasis and protection against premature atherosclerosis.

  17. A proteoliposome containing apolipoprotein A-I mutant (V156K) enhances rapid tumor regression activity of human origin oncolytic adenovirus in tumor-bearing zebrafish and mice.

    PubMed

    Seo, Juyi; Yun, Chae-Ok; Kwon, Oh-Joon; Choi, Eun-Jin; Song, Jae-Young; Choi, Inho; Cho, Kyung-Hyun

    2012-08-01

    We recently reported that the efficiency of adenoviral gene delivery and virus stability are significantly enhanced when a proteoliposome (PL) containing apolipoprotein (apo) A-I is used in an animal model. In the current study, we tested tumor removal activity of oncolytic adenovirus (Ad) using PL-containing wildtype (WT) or V156K. Oncolytic Ad with or without PL was injected into tumors of zebrafish and nude mice as a Hep3B tumor xenograft model. The V156K-PL-Ad-injected zebrafish, group showed the lowest tumor tissue volume and nucleic acids in the tumor area, whereas injection of Ad alone did not result in adequate removal of tumor activity. Reactive oxygen species (ROS) contents increased two-fold in tumor-bearing zebrafish; however, the V156K-PL-Ad injected group showed a 40% decrease in ROS levels compared to that in normal zebrafish. After reducing the tumor volume with the V156K-PL-Ad injection, the swimming pattern of the zebrafish changed to be more active and energetic. The oncolytic effect of PL-Ad containing either V156K or WT was about two-fold more enhanced in mice than that of Ad alone 34 days after the injection. Immunohistochemical analysis revealed that the PL-Ad-injected groups showed enhanced efficiency of viral delivery with elevated Ad-E1A staining and a diminished number of proliferating tumor cells. Thus, the antitumor effect of oncolytic Ad was strongly enhanced by a PL-containing apoA-I and its mutant (V156K) without causing side effects in mice and zebrafish models. PMID:22851220

  18. Apolipoprotein A-I Q[-2]X causing isolated apolipoprotein A-I deficiency in a family with analphalipoproteinemia.

    PubMed Central

    Ng, D S; Leiter, L A; Vezina, C; Connelly, P W; Hegele, R A

    1994-01-01

    We report a Canadian kindred with a novel mutation in the apolipoprotein (apo) A-I gene causing analphalipoproteinemia. The 34-yr-old proband, product of a consanguineous marriage, had bilateral retinopathy, bilateral cataracts, spinocerebellar ataxia, and tendon xanthomata. High density lipoprotein cholesterol (HDL-C) was < 0.1 mM and apoA-I was undetectable. Genomic DNA sequencing of the proband's apoA-I gene identified a nonsense mutation at codon [-2], which we designate as Q[-2]X. This mutation causes a loss of endonuclease digestion sites for both BbvI and Fnu4HI. Genotyping identified four additional homozygotes, four heterozygotes, and two unaffected subjects among the first-degree relatives. Q[-2]X homozygosity causes a selective failure to produce any portion of mature apoA-I, resulting in very low plasma level of HDL. Heterozygosity results in approximately half-normal apoA-I and HDL. Gradient gel electrophoresis and differential electroimmunodiffusion assay revealed that the HDL particles of the homozygotes had peak Stokes diameter of 7.9 nm and contained apoA-II without apoA-I (Lp-AII). Heterozygotes had an additional fraction of HDL3-like particles. Two of the proband's affected sisters had documented premature coronary heart disease. This kindred, the third reported apoA-I gene mutation causing isolated complete apoA-I deficiency, appears to be at significantly increased risk for atherosclerosis. Images PMID:8282791

  19. Expression and recovery of biologically active recombinant Apolipoprotein AI(Milano) from transgenic safflower (Carthamus tinctorius) seeds.

    PubMed

    Nykiforuk, Cory L; Shen, Yin; Murray, Elizabeth W; Boothe, Joseph G; Busseuil, David; Rhéaume, Eric; Tardif, Jean-Claude; Reid, Alexandra; Moloney, Maurice M

    2011-02-01

    Apolipoprotein AI Milano (ApoAI(Milano) ) was expressed as a fusion protein in transgenic safflower seeds. High levels of expression corresponding to 7 g of ApoAI(Milano) per kilogram of seed have been identified in a line selected for commercialization. The ApoAI(Milano) fusion protein was extracted from seed using an oilbody-based process and matured in vitro prior to final purification. This yielded a Des-1,2-ApoAI(Milano) product which was confirmed by biochemical characterization including immunoreactivity against ApoAI antibodies, isoelectric point, N-terminal sequencing and electrospray mass spectrometry. Purified Des-1,2-ApoAI(Milano) readily associated with dimyristoylphosphatidylcholine in clearance assays comparable to Human ApoAI. Its biological activity was assessed by cholesterol efflux assays using Des-1,2-ApoAI(Milano) :1-palmitoyl-2-oleoyl phosphatidylcholine complexes in vitro and in vivo. This study has established that high levels of biologically functional ApoAI(Milano) can be produced using a plant-based expression system.

  20. Synergistic interactions between transcription factors control expression of the apolipoprotein AI gene in liver cells.

    PubMed Central

    Widom, R L; Ladias, J A; Kouidou, S; Karathanasis, S K

    1991-01-01

    The gene coding for apolipoprotein AI (apoAI), a plasma protein involved in the transport of cholesterol and other lipids in the plasma, is expressed predominantly in liver and intestine. Previous work in our laboratory has shown that different cis-acting elements in the 5'-flanking region of the human apoAI gene control its expression in human hepatoma (HepG2) and colon carcinoma (Caco-2) cells. Hepatocyte-specific expression is mediated by elements within the -256 to -41 DNA region relative to the apoAI gene transcription start site (+1). In this study it was found that the -222 to -110 apoAI gene region is necessary and sufficient for expression in HepG2 cells. It was also found that this DNA region functions as a powerful hepatocyte-specific transcriptional enhancer. Gel retardation and DNase I protection experiments showed that HepG2 cells contain proteins that bind to specific sites, sites A (-214 to -192), B (-169 to -146), and C (-134 to -119), within this enhancer. Site-directed mutagenesis that prevents binding of these proteins to individual or different combinations of these sites followed by functional analysis of these mutants in HepG2 cells revealed that protein binding to any one of these sites in the absence of binding to the others was not sufficient for expression. Binding to any two of these sites in any combination was sufficient for only low levels of expression. Binding to all three sites was essential for maximal expression. These results indicate that the transcriptional activity of the apoAI gene in liver cells is dependent on synergistic interactions between transcription factors bound to its enhancer. Images PMID:1846669

  1. Simultaneous Quantification of Apolipoprotein A-I and Apolipoprotein B by Liquid-Chromatography–Multiple-Reaction–Monitoring Mass Spectrometry

    PubMed Central

    Agger, Sean A.; Marney, Luke C.; Hoofnagle, Andrew N.

    2011-01-01

    BACKGROUND If liquid-chromatography–multiple-reaction–monitoring mass spectrometry (LC-MRM/MS) could be used in the large-scale preclinical verification of putative biomarkers, it would obviate the need for the development of expensive immunoassays. In addition, the translation of novel biomarkers to clinical use would be accelerated if the assays used in preclinical studies were the same as those used in the clinical laboratory. To validate this approach, we developed a multiplexed assay for the quantification of 2 clinically well-known biomarkers in human plasma, apolipoprotein A-I and apolipoprotein B (apoA-I and apoB). METHODS We used PeptideAtlas to identify candidate peptides. Human samples were denatured with urea or trifluoroethanol, reduced and alkylated, and digested with trypsin. We compared reversed-phase chromatographic separation of peptides with normal flow and microflow, and we normalized endogenous peptide peak areas to internal standard peptides. We evaluated different methods of calibration and compared the final method with a nephelometric immunoassay. RESULTS We developed a final method using trifluoroethanol denaturation, 21-h digestion, normal flow chromatography-electrospray ionization, and calibration with a single normal human plasma sample. For samples injected in duplicate, the method had intraassay CVs <6% and interassay CVs <12% for both proteins, and compared well with immunoassay (n = 47; Deming regression, LC-MRM/MS = 1.17 × immunoassay – 36.6; Sx|y = 10.3 for apoA-I and LC-MRM/MS = 1.21 × immunoassay + 7.0; Sx|y = 7.9 for apoB). CONCLUSIONS Multiplexed quantification of proteins in human plasma/serum by LC-MRM/MS is possible and compares well with clinically useful immunoassays. The potential application of single-point calibration to large clinical studies could simplify efforts to reduce day-to-day digestion variability. PMID:20923952

  2. Apolipoprotein A-I deficiency due to a codon 84 nonsense mutation of the apolipoprotein A-I gene

    SciTech Connect

    Matsunaga, Tomoyuki; Yanagi, Hisako; Hattori, Naoko; Yamakawa, Kimiko; Yamanouchi, Yasuko; Hamaguchi, Hideo ); Hiasa, Yoshikazu; Maeda, Toshihiro ); Tanaka, Isao; Obara, Takashi )

    1991-04-01

    The molecular genetic defect of a female patient with apolipoprotein A-I (apoA-I) deficiency and premature atherosclerosis was examined. Her parents were first cousins. Her plasma density fraction from 1.063 to 1.21 g/ml contained no apoA-I on SDS/PAGE and no measurable high density lipoprotein cholesterol. Southern blot hybridization showed no gross abnormality to be present in the patient's apoA-I gene and homozygosity for a haplotype of restriction fragment length polymorphisms in the apoA-I gene region. Sequencing after amplification by PCR revealed a codon 84 nonsense mutation (CAG {r arrow} TAG, Gln {r arrow} stop) of exon 4 and a codon 37 missense mutation (GCC{r arrow} ACC, Ala {r arrow} Thr) of exon 3 in the patient's apoA-I gene. The data from dot-blot hybridization with allele-specific oligonucleotide probes indicated that she was homozygous for the apoA-I gene with regard to the two mutations. The codon 37 missense mutation was also detected in the apoA-I gene of 6 out of 60 controls, who all had normal levels of apoA-I and high density lipoprotein cholesterol, suggesting that the missense mutation is polymorphic and not associated with apoA-I deficiency. These finding indicate that homozygosity for the apoA-I gene with codon 84 nonsense mutation causes the deficiency of apoA-I and of high density lipoprotein cholesterol in the patient.

  3. Deletion of the propeptide of apolipoprotein A-I impairs exit of nascent apolipoprotein A-I from the endoplasmic reticulum.

    PubMed Central

    McLeod, R S; Robbins, C; Burns, A; Yao, Z; Pritchard, P H

    1994-01-01

    Human apolipoprotein (apo) A-I is secreted as a proprotein of 249 amino acids and is processed extracellularly to the mature form (243 amino acids) by removal of a six-residue propeptide segment. We have examined the role of the apoA-I propeptide in intracellular transport and secretion using transfected baby hamster kidney cells that secreted either proapoA-I (from the wild-type cDNA, A-Iwt) or mature-form apoA-I (from A-I delta pro, a cDNA in which the propeptide sequence was deleted). Deletion of the propeptide from the apoA-I sequence did not affect the rate of apoA-I synthesis, nor did it affect the fidelity of proteolytic removal of the prepeptide. However, the propeptide deletion caused mature-form apoA-I to accumulate within the cells as determined by pulse-chase experiments; the intracellular retention times for the mature-form apoA-I in which the propeptide was prematurely removed was three times longer than that of proapoA-I (t1/2 > 3 h compared with approximately 50 min). There was no detectable degradation of either form of newly synthesized apoA-I. Immunofluorescence microscopy revealed that, whereas the proapoA-I was located predominantly in the Golgi apparatus, large quantities of the mature-form apoA-I were detected in the endoplasmic reticulum and very little was in the Golgi apparatus of A-I delta pro-transfected cells. These findings suggest that the propeptide sequence may be involved in the intracellular transport of apoA-I from the endoplasmic reticulum to the Golgi apparatus. We propose that the function of the propeptide sequence is to facilitate efficient transport of apoA-I through the secretory pathway. Images Figure 2 Figure 3 Figure 5 Figure 6 Figure 7 PMID:7945187

  4. Fructated apolipoprotein A-I exacerbates cellular senescence in human umbilical vein endothelial cells accompanied by impaired insulin secretion activity and embryo toxicity.

    PubMed

    Park, Ki-Hoon; Kim, Jae-Yong; Choi, Inho; Kim, Jae-Ryong; Won, Kyu Chang; Cho, Kyung-Hyun

    2016-08-01

    Glycation of apolipoproteins is a major feature of the production of dysfunctional high-density lipoprotein (HDL), which is associated with the incidence of several metabolic diseases such as coronary artery disease and diabetes. In this report, fructated apoA-I (fA-I) induced by fructose treatment showed a covalently multimerized band without cross-linking, and lysine residues were irreversibly modified to prevent crosslinking. Using pancreatic β-cells, insulin secretion was impaired by fA-I in the lipid-free and reconstituted HDL (rHDL) states, by up to 35%, and 40%, respectively, under hyperglycemic conditions (25 mmol/L glucose). Treatment of human umbilical vein endothelial cells (HUVECs) with fA-I and HDL from elderly patients caused a 1.8-fold and 1.5-fold increased cellular senescence, respectively, along with increased lysosomal enlargement. In the lipid-free and rHDL states, fA-I increased embryo death by 1.5-fold and 2.5-fold, respectively, along with the production of oxidized species. Furthermore, rHDL containing fA-I (fA-I-rHDL) showed a higher isoelectric point (pI, approximately 8.5), whereas rHDL containing nA-I (nA-I-rHDL) showed a narrow band range with lower pI (around 8.0) as well as a much smaller particle size than that of nA-I-rHDL. In conclusion, fructose-mediated apoA-I fructation resulted in the severe loss of several beneficial functions of apoA-I and HDL, including anti-senescence and insulin secretion activities, accompanied with increased susceptibility to protein degradation and structural modification.

  5. Bioinformatic Analysis of Plasma Apolipoproteins A-I and A-II Revealed Unique Features of A-I/A-II HDL Particles in Human Plasma.

    PubMed

    Kido, Toshimi; Kurata, Hideaki; Kondo, Kazuo; Itakura, Hiroshige; Okazaki, Mitsuyo; Urata, Takeyoshi; Yokoyama, Shinji

    2016-01-01

    Plasma concentration of apoA-I, apoA-II and apoA-II-unassociated apoA-I was analyzed in 314 Japanese subjects (177 males and 137 females), including one (male) homozygote and 37 (20 males and 17 females) heterozygotes of genetic CETP deficiency. ApoA-I unassociated with apoA-II markedly and linearly increased with HDL-cholesterol, while apoA-II increased only very slightly and the ratio of apoA-II-associated apoA-I to apoA-II stayed constant at 2 in molar ratio throughout the increase of HDL-cholesterol, among the wild type and heterozygous CETP deficiency. Thus, overall HDL concentration almost exclusively depends on HDL with apoA-I without apoA-II (LpAI) while concentration of HDL containing apoA-I and apoA-II (LpAI:AII) is constant having a fixed molar ratio of 2 : 1 regardless of total HDL and apoA-I concentration. Distribution of apoA-I between LpAI and LpAI:AII is consistent with a model of statistical partitioning regardless of sex and CETP genotype. The analysis also indicated that LpA-I accommodates on average 4 apoA-I molecules and has a clearance rate indistinguishable from LpAI:AII. Independent evidence indicated LpAI:A-II has a diameter 20% smaller than LpAI, consistent with a model having two apoA-I and one apoA-II. The functional contribution of these particles is to be investigated. PMID:27526664

  6. Bioinformatic Analysis of Plasma Apolipoproteins A-I and A-II Revealed Unique Features of A-I/A-II HDL Particles in Human Plasma

    PubMed Central

    Kido, Toshimi; Kurata, Hideaki; Kondo, Kazuo; Itakura, Hiroshige; Okazaki, Mitsuyo; Urata, Takeyoshi; Yokoyama, Shinji

    2016-01-01

    Plasma concentration of apoA-I, apoA-II and apoA-II-unassociated apoA-I was analyzed in 314 Japanese subjects (177 males and 137 females), including one (male) homozygote and 37 (20 males and 17 females) heterozygotes of genetic CETP deficiency. ApoA-I unassociated with apoA-II markedly and linearly increased with HDL-cholesterol, while apoA-II increased only very slightly and the ratio of apoA-II-associated apoA-I to apoA-II stayed constant at 2 in molar ratio throughout the increase of HDL-cholesterol, among the wild type and heterozygous CETP deficiency. Thus, overall HDL concentration almost exclusively depends on HDL with apoA-I without apoA-II (LpAI) while concentration of HDL containing apoA-I and apoA-II (LpAI:AII) is constant having a fixed molar ratio of 2 : 1 regardless of total HDL and apoA-I concentration. Distribution of apoA-I between LpAI and LpAI:AII is consistent with a model of statistical partitioning regardless of sex and CETP genotype. The analysis also indicated that LpA-I accommodates on average 4 apoA-I molecules and has a clearance rate indistinguishable from LpAI:AII. Independent evidence indicated LpAI:A-II has a diameter 20% smaller than LpAI, consistent with a model having two apoA-I and one apoA-II. The functional contribution of these particles is to be investigated. PMID:27526664

  7. Characterization of high density lipoprotein particles in familial apolipoprotein A-I deficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our aim was to characterize HDL subspecies and fat-soluble vitamin levels in a kindred with familial apolipoprotein A-I (apoA-I) deficiency. Sequencing of the APOA1 gene revealed a nonsense mutation at codon 22, Q[22]X, with two documented homozygotes, eight heterozygotes, and two normal subjects in...

  8. The Effect of Aerobic Exercise on Total Cholesterol, High-Density Lipoprotein, Apolipoprotein B, Apolipoprotein A-I, and Percent Body Fat in Adolescent Females.

    ERIC Educational Resources Information Center

    Lungo, Diane; And Others

    The effect of aerobic exercise on total cholesterol (TC), high-density lipoprotein (HDL), apolipoprotein B (Apo B), apolioprotein A-I (Apo A-I), and percent body fat in adolescent females was studied. The control subjects (n=86) were volunteers who had completed a physical education class at least six months prior to the commencement of the study,…

  9. Apolipoprotein A-I and its mimetics for the treatment of atherosclerosis

    PubMed Central

    Smith, Jonathan D

    2011-01-01

    Although statin treatment leads consistently to a reduction in major adverse coronary events and death in clinical trials, approximately 60 to 70% residual risk of these outcomes still remains. One frontier of investigational drug research is treatment to increase HDL, the ‘good cholesterol’ that is associated with a reduced risk of coronary artery disease. HDL and its major protein apolipoprotein A-I (apoAI) are protective against atherosclerosis through several mechanisms, including the ability to mediate reverse cholesterol transport. This review focuses on the preclinical and clinical findings for two types of therapies for the treatment of atherosclerosis: apoAI-containing compounds and apoAI mimetic peptides. Both of these therapies have excellent potential to be useful clinically to promote atherosclerosis regression and stabilize existing plaques, but significant hurdles must be overcome in order to develop these approaches into safe and effective therapies. PMID:20730693

  10. Apolipoprotein A-I mutant proteins having cysteine substitutions and polynucleotides encoding same

    DOEpatents

    Oda, Michael N.; Forte, Trudy M.

    2007-05-29

    Functional Apolipoprotein A-I mutant proteins, having one or more cysteine substitutions and polynucleotides encoding same, can be used to modulate paraoxonase's arylesterase activity. These ApoA-I mutant proteins can be used as therapeutic agents to combat cardiovascular disease, atherosclerosis, acute phase response and other inflammatory related diseases. The invention also includes modifications and optimizations of the ApoA-I nucleotide sequence for purposes of increasing protein expression and optimization.

  11. Apolipoprotein A-I metabolism in cynomolgus monkey. Identification and characterization of beta-migrating pools

    SciTech Connect

    Melchior, G.W.; Castle, C.K.

    1989-07-01

    Fresh plasma from control (C) and hypercholesterolemic (HC) cynomolgus monkeys was analyzed by agarose electrophoresis-immunoblotting with antibody to cynomolgus monkey apolipoprotein (apo) A-I. Two bands were evident on the autoradiogram: an alpha-migrating band (high density lipoprotein) and a beta-migrating band that comigrated exactly with cynomolgus monkey low density lipoprotein (LDL). The presence of beta-migrating apo A-I in the plasma of these monkeys was confirmed by Geon-Pevikon preparative electrophoresis, crossed immunoelectrophoresis, and isotope dilution studies in which radiolabeled apo A-I was found to equilibrate also with alpha- and beta-migrating pools of apo A-I in the plasma. Subfractionation of C and HC plasma by agarose column chromatography (Bio-Gel A-0.5M and A-15M) followed by agarose electrophoresis-immunoblotting indicated that the beta-migrating apo A-I in C was relatively homogeneous and eluted with proteins of Mr approximately 50 kD (apo A-I(50 kD)), whereas two beta-migrating fractions were identified in HC, one that eluted with the 50-kD proteins, and the other that eluted in the LDL Mr range (apo A-I(LDL)). The apo A-I(LDL) was precipitated by antibody to cynomolgus monkey apo B. The apo A-I(50 kD) accounted for 5 +/- 1% (mean +/- SD) of the plasma apo A-I in C plasma, and 15 +/- 7% in HC plasma. No apo A-I(LDL) was detected in C plasma, but that fraction accounted for 9 +/- 7% of the apo A-I in HC plasma. These data establish the presence of multiple pools of apo A-I in the cynomolgus monkey, which must be taken into consideration in any comprehensive model of apo A-I metabolism in this species.

  12. Iowa Mutant Apolipoprotein A-I (ApoA-IIowa) Fibrils Target Lysosomes.

    PubMed

    Kameyama, Hirokazu; Nakajima, Hiroyuki; Nishitsuji, Kazuchika; Mikawa, Shiho; Uchimura, Kenji; Kobayashi, Norihiro; Okuhira, Keiichiro; Saito, Hiroyuki; Sakashita, Naomi

    2016-01-01

    The single amino acid mutation G26R in human apolipoprotein A-I (apoA-IIowa) is the first mutation that was associated with familial AApoA1 amyloidosis. The N-terminal fragments (amino acid residues 1-83) of apoA-I containing this mutation deposit as amyloid fibrils in patients' tissues and organs, but the mechanisms of cellular degradation and cytotoxicity have not yet been clarified. In this study, we demonstrated degradation of apoA-IIowa fibrils via the autophagy-lysosomal pathway in human embryonic kidney 293 cells. ApoA-IIowa fibrils induced an increase in lysosomal pH and the cytosolic release of the toxic lysosomal protease cathepsin B. The mitochondrial dysfunction caused by apoA-IIowa fibrils depended on cathepsin B and was ameliorated by increasing the degradation of apoA-IIowa fibrils. Thus, although apoA-IIowa fibril transport to lysosomes and fibril degradation in lysosomes may have occurred, the presence of an excess number of apoA-IIowa fibrils, more than the lysosomes could degrade, may be detrimental to cells. Our results thus provide evidence that the target of apoA-IIowa fibrils is lysosomes, and we thereby gained a novel insight into the mechanism of AApoA1 amyloidosis.

  13. Iowa Mutant Apolipoprotein A-I (ApoA-IIowa) Fibrils Target Lysosomes

    PubMed Central

    Kameyama, Hirokazu; Nakajima, Hiroyuki; Nishitsuji, Kazuchika; Mikawa, Shiho; Uchimura, Kenji; Kobayashi, Norihiro; Okuhira, Keiichiro; Saito, Hiroyuki; Sakashita, Naomi

    2016-01-01

    The single amino acid mutation G26R in human apolipoprotein A-I (apoA-IIowa) is the first mutation that was associated with familial AApoA1 amyloidosis. The N-terminal fragments (amino acid residues 1–83) of apoA-I containing this mutation deposit as amyloid fibrils in patients’ tissues and organs, but the mechanisms of cellular degradation and cytotoxicity have not yet been clarified. In this study, we demonstrated degradation of apoA-IIowa fibrils via the autophagy-lysosomal pathway in human embryonic kidney 293 cells. ApoA-IIowa fibrils induced an increase in lysosomal pH and the cytosolic release of the toxic lysosomal protease cathepsin B. The mitochondrial dysfunction caused by apoA-IIowa fibrils depended on cathepsin B and was ameliorated by increasing the degradation of apoA-IIowa fibrils. Thus, although apoA-IIowa fibril transport to lysosomes and fibril degradation in lysosomes may have occurred, the presence of an excess number of apoA-IIowa fibrils, more than the lysosomes could degrade, may be detrimental to cells. Our results thus provide evidence that the target of apoA-IIowa fibrils is lysosomes, and we thereby gained a novel insight into the mechanism of AApoA1 amyloidosis. PMID:27464946

  14. A model of lipid-free Apolipoprotein A-I revealed by iterative molecular dynamics simulation

    SciTech Connect

    Zhang, Xing; Lei, Dongsheng; Zhang, Lei; Rames, Matthew; Zhang, Shengli

    2015-03-20

    Apolipoprotein A-I (apo A-I), the major protein component of high-density lipoprotein, has been proven inversely correlated to cardiovascular risk in past decades. The lipid-free state of apo A-I is the initial stage which binds to lipids forming high-density lipoprotein. Molecular models of lipid-free apo A-I have been reported by methods like X-ray crystallography and chemical cross-linking/mass spectrometry (CCL/MS). Through structural analysis we found that those current models had limited consistency with other experimental results, such as those from hydrogen exchange with mass spectrometry. Through molecular dynamics simulations, we also found those models could not reach a stable equilibrium state. Therefore, by integrating various experimental results, we proposed a new structural model for lipidfree apo A-I, which contains a bundled four-helix N-terminal domain (1–192) that forms a variable hydrophobic groove and a mobile short hairpin C-terminal domain (193–243). This model exhibits an equilibrium state through molecular dynamics simulation and is consistent with most of the experimental results known from CCL/MS on lysine pairs, fluorescence resonance energy transfer and hydrogen exchange. This solution-state lipid-free apo A-I model may elucidate the possible conformational transitions of apo A-I binding with lipids in high-density lipoprotein formation.

  15. A model of lipid-free Apolipoprotein A-I revealed by iterative molecular dynamics simulation

    DOE PAGES

    Zhang, Xing; Lei, Dongsheng; Zhang, Lei; Rames, Matthew; Zhang, Shengli

    2015-03-20

    Apolipoprotein A-I (apo A-I), the major protein component of high-density lipoprotein, has been proven inversely correlated to cardiovascular risk in past decades. The lipid-free state of apo A-I is the initial stage which binds to lipids forming high-density lipoprotein. Molecular models of lipid-free apo A-I have been reported by methods like X-ray crystallography and chemical cross-linking/mass spectrometry (CCL/MS). Through structural analysis we found that those current models had limited consistency with other experimental results, such as those from hydrogen exchange with mass spectrometry. Through molecular dynamics simulations, we also found those models could not reach a stable equilibrium state. Therefore,more » by integrating various experimental results, we proposed a new structural model for lipidfree apo A-I, which contains a bundled four-helix N-terminal domain (1–192) that forms a variable hydrophobic groove and a mobile short hairpin C-terminal domain (193–243). This model exhibits an equilibrium state through molecular dynamics simulation and is consistent with most of the experimental results known from CCL/MS on lysine pairs, fluorescence resonance energy transfer and hydrogen exchange. This solution-state lipid-free apo A-I model may elucidate the possible conformational transitions of apo A-I binding with lipids in high-density lipoprotein formation.« less

  16. A Model of Lipid-Free Apolipoprotein A-I Revealed by Iterative Molecular Dynamics Simulation

    PubMed Central

    Zhang, Xing; Lei, Dongsheng; Zhang, Lei; Rames, Matthew; Zhang, Shengli

    2015-01-01

    Apolipoprotein A-I (apo A-I), the major protein component of high-density lipoprotein, has been proven inversely correlated to cardiovascular risk in past decades. The lipid-free state of apo A-I is the initial stage which binds to lipids forming high-density lipoprotein. Molecular models of lipid-free apo A-I have been reported by methods like X-ray crystallography and chemical cross-linking/mass spectrometry (CCL/MS). Through structural analysis we found that those current models had limited consistency with other experimental results, such as those from hydrogen exchange with mass spectrometry. Through molecular dynamics simulations, we also found those models could not reach a stable equilibrium state. Therefore, by integrating various experimental results, we proposed a new structural model for lipid-free apo A-I, which contains a bundled four-helix N-terminal domain (1–192) that forms a variable hydrophobic groove and a mobile short hairpin C-terminal domain (193–243). This model exhibits an equilibrium state through molecular dynamics simulation and is consistent with most of the experimental results known from CCL/MS on lysine pairs, fluorescence resonance energy transfer and hydrogen exchange. This solution-state lipid-free apo A-I model may elucidate the possible conformational transitions of apo A-I binding with lipids in high-density lipoprotein formation. PMID:25793886

  17. Contribution of polymorphisms in the apolipoprotein AI-CIII-AIV cluster to hyperlipidaemia in patients with gout

    PubMed Central

    Cardona, F; Tinahones, F; Collantes, E; Escudero, A; Garcia-Fuentes, E; Soriguer, F

    2005-01-01

    Background: Studies have shown that hyperuricaemia is independently related to the insulin resistance syndrome and that polymorphisms of the apolipoprotein AI-CIII-AIV cluster are also related to insulin resistance. Objective: To study the prevalence of polymorphisms of the apolipoprotein AI-CIII-AIV cluster in persons with gout and to determine whether these polymorphisms contribute to the pathophysiology of gout or to altered lipid concentrations. Methods: Plasma cholesterol, triglycerides, uric acid, VLDL, LDL, IDL, and HDL triglycerides, cholesterol, and the renal excretion of uric acid were measured in 68 patients with gout with gout and 165 healthy subjects. Polymorphisms were studied by amplification and RFLP in all subjects, using XmnI and MspI in the apolipoprotein AI gene and SstI in the apolipoprotein CIII gene. Results: The A allele at position –75 bp in the apolipoprotein AI gene was more common in patients with gout than in controls (p = 0.01). Levels of cholesterol, triglycerides, uric acid, basal glycaemia, and HDL cholesterol were higher in the patients (p<0.001). In the patients there was also an interaction between mutations at the two polymorphic loci studied in the apolipoprotein AI gene (p = 0.04). An absence of the mutation at position –75 bp of the apolipoprotein AI gene resulted in increased plasma triglyceride levels. Conclusions: Gouty patients have an altered allelic distribution in the apolipoprotein AI-CIII-AIV cluster, which could lead to changes in levels of lipoproteins. This is not caused by a single mutation but rather by a combination of different mutations. PMID:15115711

  18. Apolipoprotein A-I expression suppresses COX-2 expression by reducing reactive oxygen species in hepatocytes.

    PubMed

    Mao, Jing; Liu, Wei; Wang, Yutong

    2014-11-21

    Abnormal lipid metabolism may contribute to the increase of reactive oxygen species (ROS) and inflammation in the pathogenesis of non-alcoholic steatohepatitis (NASH). Apolipoprotein A-I (apoA-I) accepts cellular cholesterol and phospholipids transported by ATP-binding cassette transporter A1 to generate nascent high density lipoprotein particles. Previous studies revealed that the overexpression of ABCA1 or apoA-I alleviated hepatic lipid levels by modifying lipid transport. Here, we examined the effect of apoA-I overexpression on ROS and genes involved in inflammation in both BEL-7402 hepatocytes and mice. Human apoA-I was overexpressed by transfection in BEL-7402 hepatocytes and by an adenoviral vector in C57BL/6J mice fed a methionine choline-deficient diet. The overexpression of apoA-I in both models resulted in decreased ROS and lipid peroxidation levels, as well as a reduced MAPK phosphorylation and decreased expression levels of c-Fos and COX-2. These results suggest that apoA-I overexpression can reduce steatosis by decreasing ROS levels and suppressing COX-2-induced inflammation in hepatocytes. MAPK and c-Fos are involved in this regulatory process.

  19. Bioenergetic programming of macrophages by the apolipoprotein A-I mimetic peptide 4F.

    PubMed

    Datta, Geeta; Kramer, Philip A; Johnson, Michelle S; Sawada, Hirotaka; Smythies, Lesley E; Crossman, David K; Chacko, Balu; Ballinger, Scott W; Westbrook, David G; Mayakonda, Palgunachari; Anantharamaiah, G M; Darley-Usmar, Victor M; White, C Roger

    2015-05-01

    The apoA-I (apolipoprotein A-I) mimetic peptide 4F favours the differentiation of human monocytes to an alternatively activated M2 phenotype. The goal of the present study was to test whether the 4F-mediated differentiation of MDMs (monocyte-derived macrophages) requires the induction of an oxidative metabolic programme. 4F treatment induced several genes in MDMs that play an important role in lipid metabolism, including PPARγ (peroxisome-proliferator-activated receptor γ) and CD36. Addition of 4F was associated with a significant increase in FA (fatty acid) uptake and oxidation compared with vehicle treatment. Mitochondrial respiration was assessed by measurement of the OCR (oxygen-consumption rate). 4F increased basal and ATP-linked OCR as well as maximal uncoupled mitochondrial respiration. These changes were associated with a significant increase in ΔΨm (mitochondrial membrane potential). The increase in metabolic activity in 4F-treated MDMs was attenuated by etomoxir, an inhibitor of mitochondrial FA uptake. Finally, addition of the PPARγ antagonist T0070907 to 4F-treated MDMs reduced the expression of CD163 and CD36, cell-surface markers for M2 macrophages, and reduced basal and ATP-linked OCR. These results support our hypothesis that the 4F-mediated differentiation of MDMs to an anti-inflammatory phenotype is due, in part, to an increase in FA uptake and mitochondrial oxidative metabolism.

  20. Structural Stability and Local Dynamics in Disease-Causing Mutants of Human Apolipoprotein A-I: What Makes the Protein Amyloidogenic?

    PubMed

    Das, Madhurima; Wilson, Christopher J; Mei, Xiaohu; Wales, Thomas E; Engen, John R; Gursky, Olga

    2016-01-29

    ApoA-I, the major protein of plasma high-density lipoprotein, removes cellular cholesterol and protects against atherosclerosis. ApoA-I mutations can cause familial amyloidosis, a life-threatening disease wherein N-terminal protein fragments form fibrils in vital organs. To unveil the protein misfolding mechanism and to understand why some mutations cause amyloidosis while others do not, we analyzed the structure, stability, and lipid-binding properties of naturally occurring mutants of full-length human apoA-I causing either amyloidosis (G26R, W50R, F71Y, and L170P) or aberrant lipid metabolism (L159R). Global and local protein conformation and dynamics in solution were assessed by circular dichroism, fluorescence, and hydrogen-deuterium exchange mass spectrometry. All mutants showed increased deuteration in residues 14-22, supporting our hypothesis that decreased protection of this major amyloid "hot spot" can trigger protein misfolding. In addition, L159R showed local helical unfolding near the mutation site, consistent with cleavage of this mutant in plasma to generate the labile 1-159 fragment. Together, the results suggest that reduced protection of the major amyloid "hot spot", combined with the structural integrity of the native helix bundle conformation, shifts the balance from protein clearance to β-aggregation. A delicate balance between the overall structural integrity of a globular protein and the local destabilization of its amyloidogenic segments may be a fundamental determinant of this and other amyloid diseases. Furthermore, mutation-induced conformational changes observed in the helix bundle, which comprises the N-terminal 75% of apoA-I, and its flexible C-terminal tail suggest the propagation of structural perturbations to distant sites via an unexpected template-induced ensemble-based mechanism, challenging the classical structure-based view.

  1. Concentration and pattern changes of porcine serum apolipoprotein A-I in four different infectious diseases.

    PubMed

    Marco-Ramell, Anna; Hummel, Karin; Razzazi-Fazeli, Ebrahim; Bassols, Anna; Miller, Ingrid

    2015-02-01

    Apolipoprotein A-I (Apo A-I) is a major protein in lipid/lipoprotein metabolism and decreased serum levels have been observed in many species in response to inflammatory and infectious challenges. Little is known about the porcine homologue, therefore in this work we have characterized it through biochemical and proteomic techniques. In 2DE, porcine serum Apo A-I is found as three spots, the two more acidic ones corresponding to the mature protein, the more basic spot to the protein precursor. Despite high sequence coverage in LC-MS/MS, we did not find a sequence or PTM difference between the two mature protein species. Besides this biochemical characterization, we measured overall levels and relative species abundance of serum Apo A-I in four different viral and bacterial porcine infectious diseases. Lower overall amounts of Apo A-I were observed in Salmonella typhimurium and Escherichia coli infections. In the 2DE protein pattern, an increase of the protein precursor together with a lower level of mature protein species were detected in the porcine circovirus type 2-systemic disease and S. typhimurium infection. These results reveal that both the porcine serum Apo A-I concentration and the species pattern are influenced by the nature of the infectious disease.

  2. Importance of Apolipoprotein A-I in Multiple Sclerosis

    PubMed Central

    Gardner, Lidia A.; Levin, Michael C.

    2015-01-01

    Jean-Martin Charcot has first described multiple sclerosis (MS) as a disease of the central nervous system (CNS) over a century ago. MS remains incurable today, and treatment options are limited to disease modifying drugs. Over the years, significant advances in understanding disease pathology have been made in autoimmune and neurodegenerative components. Despite the fact that brain is the most lipid rich organ in human body, the importance of lipid metabolism has not been extensively studied in this disorder. In MS, the CNS is under attack by a person’s own immune system. Autoantigens and autoantibodies are known to cause devastation of myelin through up regulation of T-cells and cytokines, which penetrate through the blood–brain barrier to cause inflammation and myelin destruction. The anti-inflammatory role of high-density lipoproteins (HDLs) has been implicated in a plethora of biological processes: vasodilation, immunity to infection, oxidation, inflammation, and apoptosis. However, it is not known what role HDL plays in neurological function and myelin repair in MS. Understanding of lipid metabolism in the CNS and in the periphery might unveil new therapeutic targets and explain the partial success of some existing MS therapies. PMID:26635608

  3. Apolipoprotein A-I inhibits experimental colitis and colitis-propelled carcinogenesis.

    PubMed

    Gkouskou, K K; Ioannou, M; Pavlopoulos, G A; Georgila, K; Siganou, A; Nikolaidis, G; Kanellis, D C; Moore, S; Papadakis, K A; Kardassis, D; Iliopoulos, I; McDyer, F A; Drakos, E; Eliopoulos, A G

    2016-05-12

    In both humans with long-standing ulcerative colitis and mouse models of colitis-associated carcinogenesis (CAC), tumors develop predominantly in the distal part of the large intestine but the biological basis of this intriguing pathology remains unknown. Herein we report intrinsic differences in gene expression between proximal and distal colon in the mouse, which are augmented during dextran sodium sulfate (DSS)/azoxymethane (AOM)-induced CAC. Functional enrichment of differentially expressed genes identified discrete biological pathways operating in proximal vs distal intestine and revealed a cluster of genes involved in lipid metabolism to be associated with the disease-resistant proximal colon. Guided by this finding, we have further interrogated the expression and function of one of these genes, apolipoprotein A-I (ApoA-I), a major component of high-density lipoprotein. We show that ApoA-I is expressed at higher levels in the proximal compared with the distal part of the colon and its ablation in mice results in exaggerated DSS-induced colitis and disruption of epithelial architecture in larger areas of the large intestine. Conversely, treatment with an ApoA-I mimetic peptide ameliorated the phenotypic, histopathological and inflammatory manifestations of the disease. Genetic interference with ApoA-I levels in vivo impacted on the number, size and distribution of AOM/DSS-induced colon tumors. Mechanistically, ApoA-I was found to modulate signal transducer and activator of transcription 3 (STAT3) and nuclear factor-κB activation in response to the bacterial product lipopolysaccharide with concomitant impairment in the production of the pathogenic cytokine interleukin-6. Collectively, these data demonstrate a novel protective role for ApoA-I in colitis and CAC and unravel an unprecedented link between lipid metabolic processes and intestinal pathologies.

  4. Leptospiral LruA Is Required for Virulence and Modulates an Interaction with Mammalian Apolipoprotein AI

    PubMed Central

    Zhang, Kunkun; Murray, Gerald L.; Seemann, Torsten; Srikram, Amporn; Bartpho, Thanatchaporn; Sermswan, Rasana W.; Hoke, David E.

    2013-01-01

    Leptospirosis is a worldwide zoonosis caused by spirochetes of the genus Leptospira. While understanding of pathogenesis remains limited, the development of mutagenesis in Leptospira has provided a powerful tool for identifying novel virulence factors. LruA is a lipoprotein that has been implicated in leptospiral uveitis as a target of the immune response. In this study, two lruA mutants, M754 and M765, generated by transposon mutagenesis from Leptospira interrogans serovar Manilae, were characterized. In M754, the transposon inserted in the middle of lruA, resulting in no detectable expression of LruA. In M765, the transposon inserted toward the 3′ end of the gene, resulting in expression of a truncated protein. LruA was demonstrated to be on the cell surface in M765 and the wild type (WT). M754, but not M765, was attenuated in a hamster model of acute infection. A search for differential binding to human serum proteins identified a serum protein of around 30 kDa bound to the wild type and the LruA deletion mutant (M754), but not to the LruA truncation mutant (M765). Two-dimensional separation of proteins from leptospiral cells incubated with guinea pig serum identified the 28-kDa apolipoprotein A-I (ApoA-I) as a major mammalian serum protein that binds Leptospira in vitro. Interestingly, M754 (with no detectable LruA) bound more ApoA-I than did the LruA-expressing strains Manilae wild type and M765. Our data thus identify LruA as a surface-exposed leptospiral virulence factor that contributes to leptospiral pathogenesis, possibly by modulating cellular interactions with serum protein ApoA-I. PMID:23918777

  5. Effect of an isoenergetic traditional Mediterranean diet on apolipoprotein A-I kinetic in men with metabolic syndrome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of the Mediterranean diet (MedDiet) on high-density lipoprotein (HDL) kinetics has not been studied to date. The objective of this study was therefore to investigate the effect of the MedDiet in the absence of changes in body weight on apolipoprotein (apo) A-I kinetic in men with metaboli...

  6. Predictive value of serum apolipoprotein B/apolipoprotein A-I ratio in metabolic syndrome risk: a Chinese cohort study.

    PubMed

    Chou, Yu-Ching; Kuan, Jen-Chun; Bai, Chyi-Huey; Yang, Tsan; Chou, Wan-Yun; Hsieh, Po-Chien; You, San-Lin; Hwang, Lee-Ching; Chen, Chien-Hua; Wei, Cheng-Yu; Sun, Chien-An

    2015-06-01

    The purpose of this study was to evaluate whether the apolipoprotein B/apolipoprotein A-I (apoB/apoA-I) ratio is a promising risk predictor of metabolic syndrome (MetS) and to determine the optimal cut-off value of this ratio in detecting subjects with MetS in a Chinese population. A prospective study was conducted using a representative sample of non-institutionized people in Taiwan. A total of 3,343 participants with mean age (±SD) of 39.86 (±15.61) years old were followed up from 2002 to 2007. The primary outcome was the incidence of MetS. The MetS was defined according to a unified criterion established by several major organizations. There were 462 cases of incident MetS during a mean follow-up period of 5.26 years. A significantly stepwise increase in the incidence of MetS across quartiles of the apoB/apoA-I ratio was noted in both sexes after adjustment for potential confounders (p for trend <0.001). Compared with the lowest quartile of apoB/apoA-I ratio, participants in the highest quartile had a significantly higher risk of MetS in both men [adjusted hazard ratio (HR) = 6.29, 95 % confidence interval (CI) = 2.79-9.13] and women (adjusted HR = 3.82, 95 % CI = 1.06-6.63). Comparisons of receiver operating characteristics curves indicated that the predictive ability of apoB/apoA-I ratio to detect MetS was better than conventional lipid ratio measurements. Furthermore, the optimal cut-off value of apoB/apoA-I ratio for MetS diagnosis was 0.71 in men and 0.56 in women. These results suggest that an elevated apoB/apoA-I ratio might constitute a potentially crucial measure linked to the risk of developing MetS.

  7. Endotoxin contamination of apolipoprotein A-I: effect on macrophage proliferation--a cautionary tale.

    PubMed

    Jin, Xueting; Xu, Qing; Champion, Keith; Kruth, Howard S

    2015-05-01

    This technical report addresses the problem of endotoxin contamination of apolipoprotein reagents. Using a bromodeoxyuridine incorporation cell proliferation assay, we observed that human plasma ApoA-I as low as 1 μg/ml resulted in a >90% inhibition in macrophage proliferation. However, not all ApoA-I from different sources showed this effect. We considered the possibility that endotoxin contamination of the apolipoproteins contributed to the differential inhibition of macrophage cell proliferation. Endotoxin alone very potently inhibited macrophage proliferation (0.1 ng/ml inhibited macrophage proliferation>90%). Measurement of endotoxin levels in the apolipoprotein products, including an analysis of free versus total endotoxin, the latter which included endotoxin that was masked due to binding to protein, suggested that free endotoxin mediated inhibition of macrophage proliferation. Despite the use of an advanced endotoxin removal procedure and agents commonly used to inhibit endotoxin action, the potency of endotoxin precluded successful elimination of endotoxin effect. Our findings show that endotoxin contamination can significantly influence apparent apolipoprotein-mediated cell effects (or effects of any other biological products), especially when these products are tested on highly endotoxin-sensitive cells, such as macrophages.

  8. Membrane effects of N-terminal fragment of apolipoprotein A-I: a fluorescent probe study.

    PubMed

    Trusova, Valeriya; Gorbenko, Galyna; Girych, Mykhailo; Adachi, Emi; Mizuguchi, Chiharu; Sood, Rohit; Kinnunen, Paavo; Saito, Hiroyuki

    2015-03-01

    The binding of monomeric and aggregated variants of 1-83 N-terminal fragment of apolipoprotein A-I with substitution mutations G26R, G26R/W@8, G26R/W@50 and G26R/W@72 to the model lipid membranes composed of phosphatidylcholine and its mixture with cholesterol has been investigated using fluorescent probes pyrene and Laurdan. Examination of pyrene spectral behavior did not reveal any marked influence of apoA-I mutants on the hydrocarbon region of lipid bilayer. In contrast, probing the membrane effects by Laurdan revealed decrease in the probe generalized polarization in the presence of aggregated proteins. suggesting that oligomeric and fibrillar apoA-I species induce increase in hydration degree and reduction of lipid packing density in the membrane interfacial region. These findings may shed light on molecular details of amyloid cytotoxicity.

  9. Adsorption of apolipoprotein A-I to biological membranes. A statistical mechanical model

    NASA Astrophysics Data System (ADS)

    Gross, Eitan

    2012-07-01

    Apolipoprotein A-I (apo A-I), the main protein component of high-density lipoprotein (HDL), reduces the risk for atherosclerosis by removing cholesterol from the membrane of foam cells. Experiments with model membrane systems have indicated, however, that membrane cholesterol reduces apo A-I binding to the membrane. Foam cells resolve this discrepancy electrostatically by co-inserting negatively charged phospholipids in their membrane. Here we present a statistical mechanical model to account for the effect of cholesterol. Our model is based on the Haugen and May model which takes into account the dipolar nature of the zwitterionic phospholipid head group in the membrane, in which the positive end of the zwitterionic dipole moment can move randomly on a hemispherical surface with a radius equal to the arm of the dipole moment and with the negative end fixed at the hydrocarbon layer. Adsorption of a positively charged apo A-I macroion to the surface of the membrane modifies the electric field within the head group region and induces lateral demixing of phospholipid molecules in the membrane. Results from numerical integration of model equations show that i) as a result of the strong charge-dipole electrostatic coupling, the positive end of the dipoles tilts away from the adsorbed macroion in a cooperative manner; and ii) cholesterol reduces macroion adsorption to the membrane by reducing the surface area of the membrane and restricting the dipoles range of rotation. Model predictions for the change in free energy of adsorption to zwitterionic membrane are in good agreement with previously reported experimental data with liposomes. The model can assist in designing new mimetic peptides.

  10. Isolation and function analysis of apolipoprotein A-I gene response to virus infection in grouper.

    PubMed

    Wei, Jingguang; Gao, Pin; Zhang, Ping; Guo, Minglan; Xu, Meng; Wei, Shina; Yan, Yang; Qin, Qiwei

    2015-04-01

    Apolipoproteins, synthesized mainly in liver and intestine and bounded to lipids, play important roles in lipid transport and uptake through the circulation system. In this study, an apolipoprotein A-I gene homologue was cloned from orange-spotted grouper Epinephelus coioides (designed as Ec-ApoA-I) by rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA of Ec-ApoA-I was comprised of 1278 bp with a 792 bp open reading frame (ORF) that encodes a putative protein of 264 amino acids. Quantitative real-time PCR (qPCR) analysis revealed that Ec-ApoA-I was abundant in liver and intestine, and the expression in liver was significantly (P < 0.01) up-regulated after the stimulation of LPS, Poly(I:C), Vibrio alginolyticus, and Singapore grouper iridovirus (SGIV). Recombinant Ec-ApoA-I (rEc-ApoA-I) was produced in Escherichia coli BL21 (DE3) expression system exhibited bacteriolyticactivity against Microcococcus lysodeikticus and Aeromonas hydrophila. Intracellular localization revealed that Ec-ApoA-I distributed in both cytoplasm and nucleus, and predominantly in the cytoplasm. Overexpression of Ec-ApoA-I in grouper Brain (GB) cells could inhibit the replication of SGIV. These results together indicated that Ec-ApoA-I perhaps is involved in the responses to bacterial and viral challenge.

  11. Heterogeneous expression of apolipoprotein-E by human macrophages.

    PubMed

    Tedla, Nicodemus; Glaros, Elias N; Brunk, Ulf T; Jessup, Wendy; Garner, Brett

    2004-11-01

    Apolipoprotein-E (apoE) is expressed at high levels by macrophages. In addition to its role in lipid transport, macrophage-derived apoE plays an important role in immunoregulation. Previous studies have identified macrophage subpopulations that differ substantially in their ability to synthesize specific cytokines and enzymes, however, potential heterogeneous macrophage apoE expression has not been studied. Here we examined apoE expression in human THP-1 macrophages and monocyte-derived macrophages (MDM). Using immunocytochemistry and flow cytometry methods we reveal a striking heterogeneity in macrophage apoE expression in both cell types. In phorbol-ester-differentiated THP-1 macrophages, 5% of the cells over-expressed apoE at levels more than 50-fold higher than the rest of the population. ApoE over-expressing THP-1 macrophages contained condensed/fragmented nuclei and increased levels of activated caspase-3 indicating induction of apoptosis. In MDM, 3-5% of the cells also highly over-expressed apoE, up to 50-fold higher than the rest of the population; however, this was not associated with obvious nuclear alterations. The apoE over-expressing MDM were larger, more granular, and more autofluorescent than the majority of cells and they contained numerous vesicle-like structures that appeared to be coated by apoE. Flow cytometry experiments indicated that the apoE over-expressing subpopulation of MDM were positive for CD14, CD11b/Mac-1 and CD68. These observations suggest that specific macrophage subpopulations may be important for apoE-mediated immunoregulation and clearly indicate that subpopulation heterogeneity should be taken into account when investigating macrophage apoE expression.

  12. Heterogeneous expression of apolipoprotein-E by human macrophages

    PubMed Central

    Tedla, Nicodemus; Glaros, Elias N; Brunk, Ulf T; Jessup, Wendy; Garner, Brett

    2004-01-01

    Apolipoprotein-E (apoE) is expressed at high levels by macrophages. In addition to its role in lipid transport, macrophage-derived apoE plays an important role in immunoregulation. Previous studies have identified macrophage subpopulations that differ substantially in their ability to synthesize specific cytokines and enzymes, however, potential heterogeneous macrophage apoE expression has not been studied. Here we examined apoE expression in human THP-1 macrophages and monocyte-derived macrophages (MDM). Using immunocytochemistry and flow cytometry methods we reveal a striking heterogeneity in macrophage apoE expression in both cell types. In phorbol-ester-differentiated THP-1 macrophages, 5% of the cells over-expressed apoE at levels more than 50-fold higher than the rest of the population. ApoE over-expressing THP-1 macrophages contained condensed/fragmented nuclei and increased levels of activated caspase-3 indicating induction of apoptosis. In MDM, 3–5% of the cells also highly over-expressed apoE, up to 50-fold higher than the rest of the population; however, this was not associated with obvious nuclear alterations. The apoE over-expressing MDM were larger, more granular, and more autofluorescent than the majority of cells and they contained numerous vesicle-like structures that appeared to be coated by apoE. Flow cytometry experiments indicated that the apoE over-expressing subpopulation of MDM were positive for CD14, CD11b/Mac-1 and CD68. These observations suggest that specific macrophage subpopulations may be important for apoE-mediated immunoregulation and clearly indicate that subpopulation heterogeneity should be taken into account when investigating macrophage apoE expression. PMID:15500620

  13. Interactions between lipid-free apolipoprotein-AI and a lipopeptide incorporating the RGDS cell adhesion motif

    NASA Astrophysics Data System (ADS)

    Castelletto, V.; Hamley, I. W.; Reza, M.; Ruokolainen, J.

    2014-11-01

    The interaction of a designed bioactive lipopeptide C16-GGGRGDS, comprising a hexadecyl lipid chain attached to a functional heptapeptide, with the lipid-free apoliprotein, Apo-AI, is examined. This apolipoprotein is a major component of high density lipoprotein and it is involved in lipid metabolism and may serve as a biomarker for cardiovascular disease and Alzheimers' disease. We find via isothermal titration calorimetry that binding between the lipopeptide and Apo-AI occurs up to a saturation condition, just above equimolar for a 10.7 μM concentration of Apo-AI. A similar value is obtained from circular dichroism spectroscopy, which probes the reduction in α-helical secondary structure of Apo-AI upon addition of C16-GGGRGDS. Electron microscopy images show a persistence of fibrillar structures due to self-assembly of C16-GGGRGDS in mixtures with Apo-AI above the saturation binding condition. A small fraction of spheroidal or possibly ``nanodisc'' structures was observed. Small-angle X-ray scattering (SAXS) data for Apo-AI can be fitted using a published crystal structure of the Apo-AI dimer. The SAXS data for the lipopeptide/Apo-AI mixtures above the saturation binding conditions can be fitted to the contribution from fibrillar structures coexisting with flat discs corresponding to Apo-AI/lipopeptide aggregates.

  14. Apolipoprotein A-I and platelet factor 4 are biomarkers for infliximab response in rheumatoid arthritis

    PubMed Central

    Trocmé, Candice; Marotte, Hubert; Baillet, Athan; Pallot-Prades, Béatrice; Garin, Jérome; Grange, Laurent; Miossec, Pierre; Tebib, Jacques; Berger, François; Nissen, Michael J.; Juvin, Robert; Morel, Françoise; Gaudin, Philippe

    2009-01-01

    Objectives The use of biologics such as infliximab has dramatically improved the treatment of rheumatoid arthritis (RA). However, factors predictive of therapeutic response need to be identified. A proteomic study was performed prior to infliximab therapy to identify a panel of candidate protein biomarkers of RA predictive of treatment response. Methods Plasma profiles of 60 RA patients (28 non-responders ACR 20 negative and 32 responders ACR 70 positive to infliximab) were studied by SELDI-TOF-MS technology on two types of arrays, an anion exchange array (SAX2) and a nickel affinity array (IMAC3-Ni). Biomarker characterization was carried out using classical biochemical methods (purification by ammonium sulfate precipitation or metal affinity chromatography) and identification by MALDI-TOF analysis. Results Two distinct protein profiles were observed on both arrays and several proteins were differentially expressed in both patient populations. Five proteins at 3.86, 7.77, 7.97, 8.14 and 74.07 kDa were overexpressed in the non-responder group, whereas one at 28 kDa was increased in the responder population (sensitivity > 56%, specificity > 77.5%). Moreover combination of several biomarkers improved both the sensitivity and specificity of the detection of patient response to over 97%. The 28 kDa protein was characterized as apolipoprotein A-I and the 7.77 kDa biomarker was identified as platelet factor 4. Conclusions We characterized six plasma biomarkers, enabling the detection of patient response to infliximab with high sensitivity and specificity. Apolipoprotein A-1 was predictive of a good response to infliximab, whereas platelet factor 4 was associated with non-responders. PMID:18664547

  15. [Structure of the interaction sites of eukaryotic DNA with steroid hormone-apolipoprotein A-I complexes].

    PubMed

    Panin, L E; Gimautdinova, O I; Kuznetsov, P A; Velichko, E Iu; Bazaluk, V V

    2007-01-01

    A high affinity of apolipoprotein A-I for DNA and synthetic oligonucleotides was found using the affinity chromatography, affinity modification, and enzyme analysis. The competitive inhibition and Southern hybridization allowed disclosing the specificity of the interaction of the tetrahydrocortisol-apolipoprotein A-I complex (THC-ApoA-I) with high molecular weight DNA in regions contained GCC/CGG-sequences. The S1 nuclease sensitivity of the duplex CC(GCC)3 x GG(CGG)3 was found to occur under the action of THC-ApoA-I complex. The role of the interaction sites of eukaryotic DNA with steroid (THC, androsterone)-ApoA-I complexes in the initiation of the copy reaction in vitro was revealed. PMID:17936984

  16. Macrophage metalloproteinases degrade high-density-lipoprotein-associated apolipoprotein A-I at both the N- and C-termini.

    PubMed Central

    Eberini, Ivano; Calabresi, Laura; Wait, Robin; Tedeschi, Gabriella; Pirillo, Angela; Puglisi, Lina; Sirtori, Cesare R; Gianazza, Elisabetta

    2002-01-01

    Atheromatous plaques contain various cell types, including macrophages, endothelial cells and smooth-muscle cells. To investigate the possible interactions between secreted matrix metalloproteinases and high-density lipoprotein (HDL) components, we tested the above cell types by culturing them for 24 h. HDL(3) (HDL subfractions with average sizes of between 8.44 nm for HDL(3A) and 7.62 nm for HDL(3C)) were then incubated in their cell-free conditioned media. Proteolytic degradation of apolipoprotein A-I was observed with macrophages, but not with endothelial-cell- or muscle-cell-conditioned supernatant. Absence of calcium or addition of EDTA to incubation media prevented all proteolytic processes. The identified apolipoprotein A-I fragments had sizes of 26, 22, 14 and 9 kDa. Two-dimensional electrophoresis and MS resolved the 26 and the 22 kDa components and identified peptides resulting from both N- and C-terminal cleavage of apolipoprotein A-I. The higher abundance of C- than N-terminally cleaved peptides agrees with data in the literature for a fully structured alpha-helix around Tyr(18) compared with an unstructured region around Gly(185) and Gly(186). The flexibility in the latter region of apolipoprotein A-I may explain its susceptibility to proteolysis. In our experimental set-up, HDL(3C) was more extensively degraded than the other HDL(3) subclasses (HDL(3A) and HDL(3B)). Proteolytic fragments produced by metalloproteinase action were shown by gel filtration and electrophoresis to be neither associated with lipids nor self-associated. PMID:11879189

  17. Interactions of Apolipoproteins AI, AII, B and HDL, LDL, VLDL with Polyurethane and Polyurethane-PEO Surfaces.

    PubMed

    Cornelius, R M; Macri, J; Cornelius, K M; Brash, J L

    2015-11-10

    The lipoproteins (HDL, LDL, VLDL) are important components of blood present in high concentration. Surprisingly, their role in blood-biomaterial interactions has been largely ignored. In previous work apolipoprotein AI (the main protein component of HDL) was identified as a major constituent of protein layers adsorbed from plasma to biomaterials having a wide range of surface properties, and quantitative data on the adsorption of apo AI to a biomedical grade polyurethane were reported. In the present communication quantitative data on the adsorption of apo AI, apo AII and apoB (the latter being a constituent of LDL and VLDL), as well as the lipoprotein particles themselves (HDL, LDL, VLDL), to a biomedical segmented polyurethane (PU) with and without an additive containing poly(ethylene oxide) (material referred to as PEO) are reported. Using radiolabeled apo AI, apo AII, and apoB, adsorption levels on PU from buffer at a protein concentration of 50 μg/mL were found to be 0.34, 0.40, and 0.14 μg/cm(2) (12, 23, and 0.25 nmol/cm(2)) respectively. Adsorption to the PEO surface was <0.02 μg/cm(2) for all three apolipoproteins demonstrating the strong protein resistance of this material. In contrast to the apolipoproteins, significant amounts of the lipoproteins were found to adsorb to the PEO as well as to the PU surface. X-ray photoelectron spectra, following exposure of the surfaces to the lipoproteins, showed a strong phosphorus signal, confirming that adsorption had occurred. It therefore appears that a PEO-containing surface that is resistant to apolipoproteins may be less resistant to the corresponding lipoproteins.

  18. Role of apolipoprotein A-I in HDL binding to a rat hepatoma cell in culture

    SciTech Connect

    Gottlieb, B.A.

    1985-01-01

    The binding of HDL to rat Fu5AH hepatoma cells at 4/sup 0/, and uptake and degradation at 37/sup 0/, was investigated in monolayer cultures. HDL, free of apo E and apo A-IV, was obtained from the plasma of nephrotic rats (HDLne). /sup 125/I-labeled HDLne bound to the cells in a specific, saturable manner. By Scatchard analysis, two classes of binding sites were obtained: a high affinity binding site (Kd = 1.25 +/- 0.023 ..mu..g/ml, or 5 x 10/sup -9/ M), and a lower affinity site (Kd = 45 +/- 15 ..mu..g/ml, or 1.8 x 10/sup -7/ M). In competitive binding experiments, normal rat HDL was nearly as effective as HDLne, but rat VLDL and human lipoproteins were ineffective. Rat apo A-I/phospholipid complexes also did not complete effectively for HDLne binding, although they were capable of binding to the cells. However, LDL (1.02 < d < 1.063) from nephrotic rat plasma, containing 20% of apo A-I, was as effective as rat HDL in competing for HDLne binding when the competition was expressed as a function of apo A-I content. Control experiments indicated that labeled apo A-I from HDLne did not exchange appreciably with unlabeled apo A-I on the LDLne. When the hepatoma cells were allowed to internalize and degrade HDLne at 37/sup 0/, the acid-soluble products (iodotyrosine and iodide) were derived almost entirely from the breakdown of apo A-I. We conclude that the rat hepatoma cell (Fu5AH) has high affinity HDL binding sites which recognize apo A-I-lipid complexes in which apo A-I an appropriate conformation.

  19. Hereditary nephropathic systemic amyloidosis caused by a novel variant apolipoprotein A-I.

    PubMed

    Persey, M R; Booth, D R; Booth, S E; van Zyl-Smit, R; Adams, B K; Fattaar, A B; Tennent, G A; Hawkins, P N; Pepys, M B

    1998-02-01

    We report a family with autosomal-dominant hereditary systemic amyloidosis in three generations, presenting with renal involvement. Two members of the current generation received renal transplants for end-stage renal failure 16 and 18 years ago, and remain very well clinically despite massive visceral amyloidosis. Two other members of this generation, aged 32 and 47 years, have massive systemic amyloid but no clinical disability. Individuals known to be affected in previous generations died of renal failure in early adult life. Amyloid deposits in the proband, one of the transplanted individuals, were composed of apolipoprotein A-I (apoA-I), and among living family members there was complete concordance between amyloidosis and the presence of a novel 9 base pair in-frame deletion mutation in exon 4 of the apoA-I gene, causing a loss of residues Glu70Phe71Trp72. This predicts the acquisition of a single extra positive charge by mature apoA-I, and this variant was detected in the plasma of all carriers. All the previously reported amyloidogenic variants of apoA-I also carry an extra positive charge, indicating that this electrostatic change is likely to be relevant to the amyloidogenicity of apoA-I. PMID:9461086

  20. Apolipoprotein A-I from striped bass (Morone saxatilis) demonstrates antibacterial activity in vitro.

    PubMed

    Johnston, L Danielle; Brown, Gwynne; Gauthier, David; Reece, Kimberly; Kator, Howard; Van Veld, Peter

    2008-10-01

    HDL and apolipoprotein A-I from teleostean fishes demonstrate in vitro activity against gram-positive and gram-negative bacteria. In this study, we purified ApoA-1 from striped bass (Morone saxatilis) plasma and examined its in vitro antibacterial activity against Streptococcus sp., Escherichia coli, and Mycobacterium marinum. In addition, we obtained sequence for a putative striped bass ApoA-1 gene, which when translated contained the identical sequence generated from N-terminal sequencing of the purified ApoA-1. The predicted secondary and tertiary structures contained the characteristic proline residues and high alpha-helical content conserved between mammals and fishes. Purified ApoA-1 exhibited antibacterial activity against the bacteria assayed. Concentrations of 125 microg/mL for E. coli, 250 microg/mL for Streptococcus sp., and 250 microg/mL for M. marinum, inhibited bacterial growth by 50% compared to control. ApoA-1 plasma concentrations in experimental and wild fish ranged from undetectable levels to greater than 5 mg/mL, indicating that striped bass ApoA-1 is an effective antibacterial agent at concentrations below the range of physiological concentrations in striped bass plasma. We therefore conclude that ApoA-1 could play a role in innate defense against bacterial pathogens in striped bass.

  1. Matrix metalloproteinase 8 degrades apolipoprotein A-I and reduces its cholesterol efflux capacity.

    PubMed

    Salminen, Aino; Åström, Pirjo; Metso, Jari; Soliymani, Rabah; Salo, Tuula; Jauhiainen, Matti; Pussinen, Pirkko J; Sorsa, Timo

    2015-04-01

    Various cell types in atherosclerotic lesions express matrix metalloproteinase (MMP)-8. We investigated whether MMP-8 affects the structure and antiatherogenic function of apolipoprotein (apo) A-I, the main protein component of HDL particles. Furthermore, we studied serum lipid profiles and cholesterol efflux capacity in MMP-8-deficient mouse model. Incubation of apoA-I (28 kDa) with activated MMP-8 yielded 22 kDa and 25 kDa apoA-I fragments. Mass spectrometric analyses revealed that apoA-I was cleaved at its carboxyl-terminal part. Treatment of apoA-I and HDL with MMP-8 resulted in significant reduction (up to 84%, P < 0.001) in their ability to facilitate cholesterol efflux from cholesterol-loaded THP-1 macrophages. The cleavage of apoA-I by MMP-8 and the reduction in its cholesterol efflux capacity was inhibited by doxycycline. MMP-8-deficient mice had significantly lower serum triglyceride (TG) levels (P = 0.003) and larger HDL particles compared with wild-type (WT) mice. However, no differences were observed in the apoA-I levels or serum cholesterol efflux capacities between the mouse groups. Proteolytic modification of apoA-I by MMP-8 may impair the first steps of reverse cholesterol transport, leading to increased accumulation of cholesterol in the vessel walls. Eventually, inhibition of MMPs by doxycycline may reduce the risk for atherosclerotic vascular diseases.

  2. Formation of stable nanodiscs by bihelical apolipoprotein A-I mimetic peptide.

    PubMed

    Kariyazono, Hirokazu; Nadai, Ryo; Miyajima, Rin; Takechi-Haraya, Yuki; Baba, Teruhiko; Shigenaga, Akira; Okuhira, Keiichiro; Otaka, Akira; Saito, Hiroyuki

    2016-02-01

    Nanodiscs are composed of scaffold protein or peptide such as apolipoprotein A-I (apoA-I) and phospholipids. Although peptide-based nanodiscs have an advantage to modulate the size of nanodiscs by changing phospholipid/peptide ratios, they are usually less stable than apoA-I-based nanodiscs. In this study, we designed a novel nanodisc scaffold peptide (NSP) that has proline-punctuated bihelical amphipathic structure based on apoA-I mimetic peptides. NSP formed α-helical structure on 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) nanodiscs prepared by cholate dialysis method. Dynamic light scattering measurements demonstrated that diameters of NSP nanodiscs vary depending upon POPC/NSP ratios. Comparison of thermal unfolding of nanodiscs monitored by circular dichroism measurements demonstrated that NSP forms much more stable nanodiscs with POPC than monohelical peptide, 4F, exhibiting comparable stability to apoA-I-POPC nanodiscs. Intrinsic Trp fluorescence measurements showed that Trp residues of NSP exhibit more hydrophobic environment than that of 4 F on nanodiscs, suggesting the stronger interaction of NSP with phospholipids. Thus, the bihelical structure of NSP appears to increase the stability of nanodiscs because of the enhanced interaction of peptides with phospholipids. In addition, NSP as well as 4F spontaneously solubilized POPC vesicles into nanodiscs without using detergent. These results indicate that bihelical NSP forms nanodiscs with comparable stability to apoA-I and has an ability to control the size of nanodiscs simply by changing phospholipid/peptide ratios.

  3. Tubulointerstitial nephritis is a dominant feature of hereditary apolipoprotein A-I amyloidosis.

    PubMed

    Gregorini, Gina; Izzi, Claudia; Ravani, Pietro; Obici, Laura; Dallera, Nadia; Del Barba, Andrea; Negrinelli, Alessandro; Tardanico, Regina; Nardi, Matilde; Biasi, Luciano; Scalvini, Tiziano; Merlini, Giampaolo; Scolari, Francesco

    2015-06-01

    Apolipoprotein A-I is the main protein of high-density lipoprotein particles, and is encoded by the APOA1 gene. Several APOA1 mutations have been found, either affecting the lecithin:cholesterol acyltransferase activity, determining familial HDL deficiency, or resulting in amyloid formation with prevalent deposits in the kidney and liver. Evaluation of familial tubulointerstitial nephritis in patients with the Leu75Pro APOA-I amyloidosis mutation resulted in the identification of 253 carriers belonging to 50 families from Brescia, Italy. A total of 219 mutation carriers underwent clinical, laboratory, and instrumental tests. Of these, 62% had renal, hepatic, and testicular disease; 38% were asymptomatic. The disease showed an age-dependent penetrance. Tubulointerstitial nephritis was diagnosed in 49% of the carriers, 13% of whom progressed to kidney failure requiring dialysis. Hepatic involvement with elevation of cholestasis indices was diagnosed in 30% of the carriers, 38% of whom developed portal hypertension. Impaired spermatogenesis and hypogonadism was found in 68% of male carriers. The cholesterol levels were lower than normal in 80% of the mutation carriers. Thus, tubulointerstitial nephritis was highly prevalent in this large series of patients with Leu75Pro apoA-I amyloidosis. Persistent elevation of alkaline phosphatase, reduced HDL cholesterol plasma levels, and hypogonadism in men are key diagnostic features of this form of amyloidosis.

  4. The Effect of Preoperative Apolipoprotein A-I on the Prognosis of Surgical Renal Cell Carcinoma

    PubMed Central

    Guo, Shengjie; He, Xiaobo; Chen, Qian; Yang, Guangwei; Yao, Kai; Dong, Pei; Ye, Yunlin; Chen, Dong; Zhang, Zhiling; Qin, Zike; Liu, Zhuowei; Li, Zaishang; Xue, Yunfei; Zhang, Meng; Liu, Ruiwu; Zhou, Fangjian; Han, Hui

    2016-01-01

    Abstract The prognostic value of serum lipid-profile in renal cell cancer (RCC) remains unknown. The purpose of the study is to explore the association between the serum lipid-profile and RCC patients. The levels of preoperative serum lipid-profile (including cholesterol, triglycerides, high-density lipoprotein-cholesterol [HDL-C], low-density lipoprotein-cholesterol [LDL-C], apolipoprotein A-I [ApoA-I], and apolipoprotein B [ApoB]) were retrospectively performed in 786 patients with RCC. The cutoff values of the lipids were determined by the receiver-operating characteristic (ROC) curve analysis. Univariate and multivariate Cox regression analyses were performed to investigate the prognostic value of serum lipids in RCC. Combined ROC analysis and univariate and multivariate Cox regression analyses, for overall survival (OS), revealed patients with low ApoA-I (<1.04) had significantly lower OS than the high ApoA-I (≥1.04) group (multivariate Cox regression analyses, hazard ratio [HR], 0.57; P = 0.003). Not only in the whole RCC cohort but also in the subgroups stratified according to the pT1-2 (P = 0.002), pN0 (P < 0.001), and pM0 (P = 0.001) status, respectively. Moreover, in the 755 patients with nonmetastasis, the low ApoA-I group was also associated with shortened disease-free survival (DFS) time compared to the high ApoA-I group (multivariate Cox regression analyses, HR, 0.65; P = 0.033). However, the other lipids were not independent prognostic factors for surgical RCC. An elevated level of preoperative ApoA-I was demonstrated to be related with better survival in patients with surgical RCC. Measuring the preoperative ApoA-I might be a simple way for finding the poor prognostic patients who should enrolled in further clinical trials and management. PMID:27015197

  5. Lipid-free Apolipoprotein A-I Structure: Insights into HDL Formation and Atherosclerosis Development.

    PubMed

    Mei, Xiaohu; Atkinson, David

    2015-07-01

    Apolipoprotein A-I is the major protein in high-density lipoprotein (HDL) and plays an important role during the process of reverse cholesterol transport (RCT). Knowledge of the high-resolution structure of full-length apoA-I is vital for a molecular understanding of the function of HDL at the various steps of the RCT pathway. Due to the flexible nature of apoA-I and aggregation properties, the structure of full-length lipid-free apoA-I has evaded description for over three decades. Sequence analysis of apoA-I suggested that the amphipathic α-helix is the structural motif of exchangeable apolipoprotein, and NMR, X-ray and MD simulation studies have confirmed this. Different laboratories have used different methods to probe the secondary structure distribution and organization of both the lipid-free and lipid-bound apoA-I structure. Mutation analysis, synthetic peptide models, surface chemistry and crystal structures have converged on the lipid-free apoA-I domain structure and function: the N-terminal domain [1-184] forms a helix bundle while the C-terminal domain [185-243] mostly lacks defined structure and is responsible for initiating lipid-binding, aggregation and is also involved in cholesterol efflux. The first 43 residues of apoA-I are essential to stabilize the lipid-free structure. In addition, the crystal structure of C-terminally truncated apoA-I suggests a monomer-dimer conversation mechanism mediated through helix 5 reorganization and dimerization during the formation of HDL. Based on previous research, we have proposed a structural model for full-length monomeric apoA-I in solution and updated the HDL formation mechanism through three states. Mapping the known natural mutations on the full-length monomeric apoA-I model provides insight into atherosclerosis development through disruption of the N-terminal helix bundle or deletion of the C-terminal lipid-binding domain.

  6. Interaction of apolipoprotein A-I with lecithin-cholesterol vesicles in the presence of phospholipase C.

    PubMed

    Gudheti, Manasa V; Gonzalez, Yamaira I; Lee, Sum P; Wrenn, Steven P

    2003-12-30

    Here we study the anti-nucleating mechanism of apolipoprotein A-I (apo A-I) on model biliary vesicles in the presence of phospholipase C (PLC) utilizing dynamic light scattering (DLS), steady-state fluorescence spectroscopy, cryogenic transmission electron microscopy (cryo-TEM), and UV/Vis spectroscopy. PLC induces aggregation of cholesterol-free lecithin vesicles from an initial, average size of 100 nm to a maximal size of 600 nm. The presence of apo A-I likely inhibits vesicle aggregation by shielding the PLC-generated hydrophobic moieties, which results in vesicles of an average size of 200 nm. A similar phenomenon is observed in cholesterol-enriched lecithin vesicles. Whereas PLC alone produces aggregates of 300 nm, no aggregation is observed when apo A-I is present along with PLC. However, the ability of apo A-I to inhibit aggregation is temporary, and after 8 h, a broad particle size distribution with sizes as high as 800 nm is observed. Apo A-I possibly induces the formation of small apo A-I/lecithin/cholesterol complexes of about 5-20 nm similar to the discoidal pre-HDL complexes found in blood when it can no longer effectively shield all the DAG molecules. Concomitant with formation of complexes, DAG molecules coalesce into large oil droplets, which account for the large particles observed by light scattering. Thus, apo A-I acts as an anti-nucleating agent by two mechanisms, anti-aggregation and microstructural transition. The mode of protection is dependent on the cholesterol content and the relative amounts of DAG and apo A-I present. This study supports the possibility of apo A-I solubilizing lipids in bile in a similar fashion as it does in blood and also delineates the mechanism of formation of the complexes.

  7. Surface-induced assembly of apolipoprotein A-I: Implications for symmetry-driven non-cooperative clustering

    NASA Astrophysics Data System (ADS)

    Winford, Sidney; Tobin, Moriah; Gross, Eitan

    2012-03-01

    In condensed matter physics the geometry of a crystal is determined by the mechanism of condensation. In biology, the link between clustering mechanisms and the shape of a protein crystal is not well defined. To gain more insight into the problem, we studied clustering of apolipoprotein A-I (apo A-I) on a solid surface using AFM. The amyloidogenic protein apo A-I is the main protein component of high density lipoprotein and thus reduces the risk of atherosclerosis. We found that apo A-I clustered to form nano-scale, symmetrical clusters on mica. Statistical analysis of size distribution for several thousand clusters suggested that the clustering reaction followed a non-cooperative kinetic scheme characterized by a single equilibrium constant of 0.92·106 M-1 and a change in free energy (ΔG) of -0.03 kJ mole-1/residue. This is close to ΔG of-0.04 kJ mole-1/residue for apo A-I binding to phospholipid membrane; and 30-fold smaller than ΔG for β-amyloid formation by apo A-I. The high symmetry of the clusters is consistent with an isotropic diffusion coefficient of protein monomers on the surface of the substrate. This previously unrecognized link between protein clustering mechanism and the symmetry of the growth pattern may have important implications in medicine, pharmaceutics and polymer science.

  8. Myeloperoxidase-mediated Methionine Oxidation Promotes an Amyloidogenic Outcome for Apolipoprotein A-I.

    PubMed

    Chan, Gary K L; Witkowski, Andrzej; Gantz, Donald L; Zhang, Tianqi O; Zanni, Martin T; Jayaraman, Shobini; Cavigiolio, Giorgio

    2015-04-24

    High plasma levels of apolipoprotein A-I (apoA-I) correlate with cardiovascular health, whereas dysfunctional apoA-I is a cause of atherosclerosis. In the atherosclerotic plaques, amyloid deposition increases with aging. Notably, apoA-I is the main component of these amyloids. Recent studies identified high levels of oxidized lipid-free apoA-I in atherosclerotic plaques. Likely, myeloperoxidase (MPO) secreted by activated macrophages in atherosclerotic lesions is the promoter of such apoA-I oxidation. We hypothesized that apoA-I oxidation by MPO levels similar to those present in the artery walls in atherosclerosis can promote apoA-I structural changes and amyloid fibril formation. ApoA-I was exposed to exhaustive chemical (H2O2) oxidation or physiological levels of enzymatic (MPO) oxidation and incubated at 37 °C and pH 6.0 to induce fibril formation. Both chemically and enzymatically oxidized apoA-I produced fibrillar amyloids after a few hours of incubation. The amyloid fibrils were composed of full-length apoA-I with differential oxidation of the three methionines. Met to Leu apoA-I variants were used to establish the predominant role of oxidation of Met-86 and Met-148 in the fibril formation process. Importantly, a small amount of preformed apoA-I fibrils was able to seed amyloid formation in oxidized apoA-I at pH 7.0. In contrast to hereditary amyloidosis, wherein specific mutations of apoA-I cause protein destabilization and amyloid deposition, oxidative conditions similar to those promoted by local inflammation in atherosclerosis are sufficient to transform full-length wild-type apoA-I into an amyloidogenic protein. Thus, MPO-mediated oxidation may be implicated in the mechanism that leads to amyloid deposition in the atherosclerotic plaques in vivo.

  9. Surface behavior of apolipoprotein A-I and its deletion mutants at model lipoprotein interfaces.

    PubMed

    Wang, Libo; Mei, Xiaohu; Atkinson, David; Small, Donald M

    2014-03-01

    Apolipoprotein A-I (apoA-I) has a great conformational flexibility to exist in lipid-free, lipid-poor, and lipid-bound states during lipid metabolism. To address the lipid binding and the dynamic desorption behavior of apoA-I at lipoprotein surfaces, apoA-I, Δ(185-243)apoA-I, and Δ(1-59)(185-243)apoA-I were studied at triolein/water and phosphatidylcholine/triolein/water interfaces with special attention to surface pressure. All three proteins are surface active to both interfaces lowering the interfacial tension and thus increasing the surface pressure to modify the interfaces. Δ(185-243)apoA-I adsorbs much more slowly and lowers the interfacial tension less than full-length apoA-I, confirming that the C-terminal domain (residues 185-243) initiates the lipid binding. Δ(1-59)(185-243)apoA-I binds more rapidly and lowers the interfacial tension more than Δ(185-243)apoA-I, suggesting that destabilizing the N-terminal α-helical bundle (residues 1-185) restores lipid binding. The three proteins desorb from both interfaces at different surface pressures revealing that different domains of apoA-I possess different lipid affinity. Δ(1-59)(185-243)apoA-I desorbs at lower pressures compared with apoA-I and Δ(185-243)apoA-I indicating that it is missing a strong lipid association motif. We propose that during lipoprotein remodeling, surface pressure mediates the adsorption and partial or full desorption of apoA-I allowing it to exchange among different lipoproteins and adopt various conformations to facilitate its multiple functions.

  10. Myeloperoxidase-mediated Methionine Oxidation Promotes an Amyloidogenic Outcome for Apolipoprotein A-I*

    PubMed Central

    Chan, Gary K. L.; Witkowski, Andrzej; Gantz, Donald L.; Zhang, Tianqi O.; Zanni, Martin T.; Jayaraman, Shobini; Cavigiolio, Giorgio

    2015-01-01

    High plasma levels of apolipoprotein A-I (apoA-I) correlate with cardiovascular health, whereas dysfunctional apoA-I is a cause of atherosclerosis. In the atherosclerotic plaques, amyloid deposition increases with aging. Notably, apoA-I is the main component of these amyloids. Recent studies identified high levels of oxidized lipid-free apoA-I in atherosclerotic plaques. Likely, myeloperoxidase (MPO) secreted by activated macrophages in atherosclerotic lesions is the promoter of such apoA-I oxidation. We hypothesized that apoA-I oxidation by MPO levels similar to those present in the artery walls in atherosclerosis can promote apoA-I structural changes and amyloid fibril formation. ApoA-I was exposed to exhaustive chemical (H2O2) oxidation or physiological levels of enzymatic (MPO) oxidation and incubated at 37 °C and pH 6.0 to induce fibril formation. Both chemically and enzymatically oxidized apoA-I produced fibrillar amyloids after a few hours of incubation. The amyloid fibrils were composed of full-length apoA-I with differential oxidation of the three methionines. Met to Leu apoA-I variants were used to establish the predominant role of oxidation of Met-86 and Met-148 in the fibril formation process. Importantly, a small amount of preformed apoA-I fibrils was able to seed amyloid formation in oxidized apoA-I at pH 7.0. In contrast to hereditary amyloidosis, wherein specific mutations of apoA-I cause protein destabilization and amyloid deposition, oxidative conditions similar to those promoted by local inflammation in atherosclerosis are sufficient to transform full-length wild-type apoA-I into an amyloidogenic protein. Thus, MPO-mediated oxidation may be implicated in the mechanism that leads to amyloid deposition in the atherosclerotic plaques in vivo. PMID:25759391

  11. Influence of Apolipoprotein (Apo) A-I Structure on Nascent High Density Lipoprotein (HDL) Particle Size Distribution*

    PubMed Central

    Vedhachalam, Charulatha; Chetty, Palaniappan Sevugan; Nickel, Margaret; Dhanasekaran, Padmaja; Lund-Katz, Sissel; Rothblat, George H.; Phillips, Michael C.

    2010-01-01

    The principal protein of high density lipoprotein (HDL), apolipoprotein (apo) A-I, in the lipid-free state contains two tertiary structure domains comprising an N-terminal helix bundle and a less organized C-terminal domain. It is not known how the properties of these domains modulate the formation and size distribution of apoA-I-containing nascent HDL particles created by ATP-binding cassette transporter A1 (ABCA1)-mediated efflux of cellular phospholipid and cholesterol. To address this issue, proteins corresponding to the two domains of human apoA-I (residues 1–189 and 190–243) and mouse apoA-I (residues 1–186 and 187–240) together with some human/mouse domain hybrids were examined for their abilities to form HDL particles when incubated with either ABCA1-expressing cells or phospholipid multilamellar vesicles. Incubation of human apoA-I with cells gave rise to two sizes of HDL particles (hydrodynamic diameter, 8 and 10 nm), and removal or disruption of the C-terminal domain eliminated the formation of the smaller particle. Variations in apoA-I domain structure and physical properties exerted similar effects on the rates of formation and sizes of HDL particles created by either spontaneous solubilization of phospholipid multilamellar vesicles or the ABCA1-mediated efflux of cellular lipids. It follows that the sizes of nascent HDL particles are determined at the point at which cellular phospholipid and cholesterol are solubilized by apoA-I; apparently, this is the rate-determining step in the overall ABCA1-mediated cellular lipid efflux process. The stability of the apoA-I N-terminal helix bundle domain and the hydrophobicity of the C-terminal domain are important determinants of both nascent HDL particle size and their rate of formation. PMID:20679346

  12. Apolipoprotein A-I mimetic peptide helix number and helix linker influence potentially anti-atherogenic properties

    PubMed Central

    Wool, Geoffrey D.; Reardon, Catherine A.; Getz, Godfrey S.

    2008-01-01

    We hypothesize that apolipoprotein A-I (apoA-I) mimetic peptides better mimicking the punctuated α-helical repeats of full-length apoA-I are more anti-inflammatory and anti-atherogenic. This study compares a monomeric apoA-I mimetic helix to three different tandem helix peptides in vitro: 4F (18 mer), 4F-proline-4F (37 mer, Pro), 4F-alanine-4F (37 mer, Ala), and 4F-KVEPLRA-4F [the human apoA-I 4/5 interhelical sequence (IHS), 43 mer]. All peptides cleared turbid lipid suspensions, with 4F being most effective. In contrast to lipid clearance, tandem peptides were more effective at remodeling mouse HDL. All four peptides displaced apoA-I and apoE from the HDL, leaving a larger particle containing apoA-II and peptide. Peptide-remodeled HDL particles show no deficit in ABCG1 cholesterol efflux despite the loss of the majority of apoA-I. Tandem peptides show greater ability to efflux cholesterol from lipid-loaded murine macrophages, compared with 4F. Although 4F inhibited oxidation of purified mouse LDL, the Ala tandem peptide increased oxidation. We compared several tandem 4F-based peptides with monomeric 4F in assays that correlated with suggested anti-inflammatory/anti-atherogenic pathways. Tandem 4F-based peptides, which better mimic full-length apoA-I, exceed monomeric 4F in HDL remodeling and cholesterol efflux but not LDL oxidation protection. In addition, apoA-I mimetic peptides may increase reverse cholesterol transport through both ABCA1 as well as ABCG1 pathways. PMID:18323574

  13. A case report of hereditary apolipoprotein A-I amyloidosis associated with a novel APOA1 mutation and variable phenotype.

    PubMed

    Tougaard, Birgitte G; Pedersen, Katja Venborg; Krag, Søren Rasmus; Gilbertson, Janet A; Rowczenio, Dorota; Gillmore, Julian D; Birn, Henrik

    2016-09-01

    Apolipoprotein A-I (apo A-I) amyloidosis is a non-AL, non-AA, and non-transthyretin type of amyloidosis associated with mutations in the APOA1 gene inherited in an autosomal dominant fashion. It is a form of systemic amyloidosis, but at presentation, can also mimic localized amyloidosis. The renal presentation generally involves interstitial and medullary deposition of apo A-I amyloid protein. We describe the identification of apo A-I amyloidosis by mass spectrometry in a 52-year old male, with no family history of amyloidosis, presenting with nephrotic syndrome and associated with heterozygosity for a novel APOA1 mutation (c.220 T > A) which encodes the known amyloidogenic Trp50Arg variant. Renal amyloid deposits in this case were confined to the glomeruli alone, and the patient developed progressive renal impairment. One year after diagnosis, the patient had a successful kidney transplant from an unrelated donor. Pathogenic mutations in the APOA1 gene are generally associated with symptoms of amyloidosis. In this family however, genotyping of family members identified several unaffected carriers suggesting a variable disease penetrance, which has not been described before in this form of amyloidosis and has implications when counselling those with APOA1 mutations. PMID:27240838

  14. A case report of hereditary apolipoprotein A-I amyloidosis associated with a novel APOA1 mutation and variable phenotype.

    PubMed

    Tougaard, Birgitte G; Pedersen, Katja Venborg; Krag, Søren Rasmus; Gilbertson, Janet A; Rowczenio, Dorota; Gillmore, Julian D; Birn, Henrik

    2016-09-01

    Apolipoprotein A-I (apo A-I) amyloidosis is a non-AL, non-AA, and non-transthyretin type of amyloidosis associated with mutations in the APOA1 gene inherited in an autosomal dominant fashion. It is a form of systemic amyloidosis, but at presentation, can also mimic localized amyloidosis. The renal presentation generally involves interstitial and medullary deposition of apo A-I amyloid protein. We describe the identification of apo A-I amyloidosis by mass spectrometry in a 52-year old male, with no family history of amyloidosis, presenting with nephrotic syndrome and associated with heterozygosity for a novel APOA1 mutation (c.220 T > A) which encodes the known amyloidogenic Trp50Arg variant. Renal amyloid deposits in this case were confined to the glomeruli alone, and the patient developed progressive renal impairment. One year after diagnosis, the patient had a successful kidney transplant from an unrelated donor. Pathogenic mutations in the APOA1 gene are generally associated with symptoms of amyloidosis. In this family however, genotyping of family members identified several unaffected carriers suggesting a variable disease penetrance, which has not been described before in this form of amyloidosis and has implications when counselling those with APOA1 mutations.

  15. Apolipoprotein A-I configuration and cell cholesterol efflux activity of discoidal lipoproteins depend on the reconstitution process.

    PubMed

    Cuellar, Luz Ángela; Prieto, Eduardo Daniel; Cabaleiro, Laura Virginia; Garda, Horacio Alberto

    2014-01-01

    Discoidal high-density lipoproteins (D-HDL) are critical intermediates in reverse cholesterol transport. Most of the present knowledge of D-HDL is based on studies with reconstituted lipoprotein complexes of apolipoprotein A-I (apoA-I) obtained by cholate dialysis (CD). D-HDL can also be generated by the direct microsolubilization (DM) of phospholipid vesicles at the gel/fluid phase transition temperature, a process mechanistically similar to the "in vivo" apoAI lipidation via ABCA1. We compared the apoA-I configuration in D-HDL reconstituted with dimyristoylphosphatidylcholine by both procedures using fluorescence resonance energy transfer measurements with apoA-I tryptophan mutants and fluorescently labeled cysteine mutants. Results indicate that apoA-I configuration in D-HDL depends on the reconstitution process and are consistent with a "double belt" molecular arrangement with different helix registry. As reported by others, a configuration with juxtaposition of helices 5 of each apoAI monomer (5/5 registry) predominates in D-HDL obtained by CD. However, a configuration with helix 5 of one monomer juxtaposed with helix 2 of the other (5/2 registry) would predominate in D-HDL generated by DM. Moreover, we also show that the kinetics of cholesterol efflux from macrophage cultures depends on the reconstitution process, suggesting that apoAI configuration is important for this HDL function. PMID:24201377

  16. Role of thyroid hormones in apolipoprotein A-I gene expression in rat liver.

    PubMed Central

    Strobl, W; Gorder, N L; Lin-Lee, Y C; Gotto, A M; Patsch, W

    1990-01-01

    To study the regulation of hepatic apo A-I gene expression, we measured synthesis and abundance of cellular apo A-I mRNA and its nuclear precursors in livers of hypothyroid and hyperthyroid rats. In hypothyroid animals, both synthesis and abundance of apo A-I mRNA was reduced to half of control values. After injection of a receptor-saturating dose of triiodothyronine into euthyroid rats, apo A-I gene transcription increased at 20 min, reached a maximum of 179% of control (P less than 0.01) at 3.5 h, and remained elevated for up to 48 h. The abundance of nuclear and total cellular apo A-I mRNA increased at 1 and 2 h, respectively, and exceeded the levels expected from enhanced transcription more than two fold at 24 h after hormone injection. Upon chronic administration of thyroid hormones, levels of nuclear and cytoplasmic apo A-I mRNA remained elevated but transcription of the apo A-I gene fell to 42% of control (P less than 0.01). Thus, thyroid hormones rapidly stimulate apo A-I gene transcription. Posttranscriptional events leading to increased stability of nuclear apo A-I RNA precursors become the principal mechanism for enhanced gene expression in chronic hyperthyroidism and may cause feedback inhibition of apo A-I gene transcription. Our results furthermore imply that the majority of hepatic nuclear apo A-I RNA precursors are degraded in euthyroid animals. Images PMID:2107206

  17. Characterization of High Density Lipoprotein Particles in Familial Apolipoprotein A-I Deficiency With Premature Coronary Atherosclerosis, Corneal Arcus and Opacification, and Tubo-Eruptive and Planar Xanthomas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We describe two male siblings with homozygous familial apolipoprotein (apo) A-I deficiency, markedly decreased high density lipoprotein (HDL) cholesterol levels, undetectable plasma apoA-1, tubo-eruptive and planar xanthomas, and mild corneal arcus and opacification. Sequencing of the apoA-I gene re...

  18. Intake of cooked tomato sauce preserves coronary endothelial function and improves apolipoprotein A-I and apolipoprotein J protein profile in high-density lipoproteins.

    PubMed

    Vilahur, Gemma; Cubedo, Judit; Padró, Teresa; Casaní, Laura; Mendieta, Guiomar; González, Alicia; Badimon, Lina

    2015-07-01

    Intake of tomatoes has been linked with healthy diets (eg, Mediterranean diet). However, it remains unknown whether tomato intake exerts protective effects on the vasculature. The aim of this study was to determine whether medium-term supplementation with cooked tomato sauce (CTS) Mediterranean style (sofrito) attenuates diet-induced coronary endothelial dysfunction in an animal model with clinical impact and explore the mechanisms behind the effects. Pigs (N = 18) were fed a 10-day hypercholesterolemic diet. Half of the animals were given a supplement of 100 g/d of CTS (21.5 mg lycopene per day). Coronary responses to escalating doses of vasoactive drugs (acetylcholine, calcium ionophore, and sodium nitroprusside) and L-NG-monomethylarginine (endothelial nitric oxide synthase [eNOS] inhibitor) were measured using flow Doppler. In the coronary arteries, we investigated eNOS gene expression and activation, monocyte chemoattractant protein 1 (MCP-1) expression, and oxidative DNA damage. In the circulation, we investigated lipoprotein resistance to oxidation and the differential proteomic protein profile. In dyslipidemic animals, CTS intake prevented diet-induced impairment of receptor-operated and nonreceptor-operated endothelial-dependent coronary vasodilation. These beneficial effects were associated with enhanced eNOS transcription and activation and diminished DNA damage in the coronary arteries. CTS-fed animals showed lower lipid peroxidation, higher high-density lipoprotein (HDL) antioxidant potential and plasma lycopene levels of 0.16 mg/L. Interestingly, improved HDL functionality was associated with protein profile changes in apolipoprotein A-I and apolipoprotein J. Lipids levels and MCP-1 expression were not affected by CTS. We report that CTS intake protects against low-density lipoprotein-induced coronary endothelial dysfunction by reducing oxidative damage, enhancing eNOS expression and activity, and improving HDL functionality.

  19. Effect of dietary omega-3 fatty acids on high-density lipoprotein apolipoprotein AI kinetics in type II diabetes mellitus.

    PubMed

    Frénais, R; Ouguerram, K; Maugeais, C; Mahot, P; Charbonnel, B; Magot, T; Krempf, M

    2001-07-01

    The effect of a dietary fish oil supplementation on metabolism of HDL was studied in type II diabetes mellitus. Endogenous labeling of HDL-apo AI was performed using a 14 h primed infusion of D3-leucine in five diabetic patients before and 2 months after treatment with maxEPA(R). Isotopic enrichment curves were analyzed using a monoexponential function. After treatment, plasma cholesterol level remained unchanged (205.4+/-41.9 vs. 206.8+/-30.7 mg/dl, NS), whereas plasma triglycerides were decreased (155.4+/-67.9 vs. 202.6+/-32.2 mg/dl, P=0.06). Plasma apo AI was similar under maxEPA(R) (116.0+/-25.6 vs. 111.8+/-25.4 mg/dl, NS), and HDL-cholesterol and HDL-triglycerides were also not markedly changed (30.2+/-10.0 vs. 27.1+/-10 mg/dl, and 15.3+/-9.8 vs. 19.2+/-10.4 mg/dl, NS). HDL-apo AI fractional catabolic rate (FCR) and absolute production rate (APR) were significantly decreased after treatment with maxEPA(R) (0.27+/-0.09 vs. 0.37+/-0.08 pool day, P<0.05, and 12.1+/-2.8 vs. 16.1+/-3.3 mg/kg per day, P<0.05). These findings showed an effect of maxEPA(R) on kinetics of apolipoprotein AI in type II diabetes mellitus, probably linked to changes in plasma triglyceride level.

  20. Molecular characterization and developmental expression patterns of apolipoprotein A-I in Senegalese sole (Solea senegalensis Kaup).

    PubMed

    Román-Padilla, J; Rodríguez-Rúa, A; Manchado, M; Hachero-Cruzado, I

    2016-05-01

    The apolipoprotein A-I (ApoA-I) is an essential component of the high density lipoproteins (HDL). In this study, the cDNA and genomic sequences of this apolipoprotein were characterized for first time in Solea senegalensis. The predicted polypeptide revealed conserved structural features including ten repeats in the lipid-binding domain and some residues involved in cholesterol interaction and binding. The gene structure analysis identified four exons and three introns. Moreover, the synteny analysis revealed that apoA-I did not localize with other apolipoproteins indicating a divergent evolution with respect to the apoA-IV and apoE cluster. The phylogenetic analyses identified two distinct apoA-I paralogs in Ostariophysi (referred to as Ia and Ib) and only one (Ib) in Acanthopterygii. Whole-mount in situ hybridization located the apoA-I signal mainly in the yolk syncytial layer in lecitotrophic larval stages. Later at mouth opening, the mRNA signals were detected mainly in liver and intestine compatible with its role in the HDL formation. Moreover, a clear signal was detected in some regions of the brain, retina and neural cord suggesting a role in local regulation of cholesterol homeostasis. After metamorphosis, apoA-I was also detected in other tissues such as gills, head kidney and spleen suggesting a putative role in immunity. Expression analyses in larvae fed two diets with different triacylglycerol levels indicated that apoA-I mRNA levels were more associated to larval size and development than dietary lipid levels. Finally, qPCR analyses of immature and mature transcripts revealed distinct expression profiles suggesting a posttranscriptional regulatory mechanism.

  1. Inhibition of inflammatory signaling pathways in 3T3-L1 adipocytes by apolipoprotein A-I.

    PubMed

    Sultana, Afroza; Cochran, Blake J; Tabet, Fatiha; Patel, Mili; Torres, Luisa Cuesta; Barter, Philip J; Rye, Kerry-Anne

    2016-06-01

    Activation of inflammatory signaling pathways links obesity with metabolic disorders. TLR4-mediated activation of MAPKs and NF-κB are 2 such pathways implicated in obesity-induced inflammation. Apolipoprotein A-I (apoA-I) exerts anti-inflammatory effects on adipocytes by effluxing cholesterol from the cells via the ATP binding cassette transporter A1 (ABCA1). It is not known if these effects involve inhibition of inflammatory signaling pathways by apoA-I. This study asks if apoA-I inhibits activation of MAPKs and NF-κB in mouse 3T3-L1 adipocytes and whether this inhibition is ABCA1 dependent. Incubation of differentiated 3T3-L1 adipocytes with apoA-I decreased cell surface expression of TLR4 by 16 ± 2% and synthesis of the TLR4 adaptor protein, myeloid differentiation primary response 88, by 24 ± 4% in an ABCA1-dependent manner. ApoA-I also inhibited downstream activation of MAPKs, such as ERK, p38MAPK, and JNK, as well as expression of proinflammatory adipokines in bacterial LPS-stimulated 3T3-L1 adipocytes in an ABCA1-dependent manner. ApoA-I, by contrast, suppressed nuclear localization of the p65 subunit of NF-κB by 30 ± 3% in LPS-stimulated 3T3-L1 adipocytes in an ABCA1-independent manner. In conclusion, apoA-I inhibits TLR4-mediated inflammatory signaling pathways in adipocytes by preventing MAPK and NF-κB activation.-Sultana, A., Cochran, B. J., Tabet, F., Patel, M., Cuesta Torres, L., Barter, P. J., Rye, K.-A. Inhibition of inflammatory signaling pathways in 3T3-L1 adipocytes by apolipoprotein A-I.

  2. The specific amino acid sequence between helices 7 and 8 influences the binding specificity of human apolipoprotein A-I for high density lipoprotein (HDL) subclasses: a potential for HDL preferential generation.

    PubMed

    Carnemolla, Ronald; Ren, Xuefeng; Biswas, Tapan K; Meredith, Stephen C; Reardon, Catherine A; Wang, Jianjun; Getz, Godfrey S

    2008-06-01

    Humans have two major high density lipoprotein (HDL) sub-fractions, HDL(2) and HDL(3), whereas mice have a monodisperse HDL profile. Epidemiological evidence has suggested that HDL(2) is more atheroprotective; however, currently there is no direct experimental evidence to support this postulate. The amino acid sequence of apoA-I is a primary determinant of HDL subclass formation. The majority of the alpha-helical repeats in human apoA-I are proline-punctuated. A notable exception is the boundary between helices 7 and 8, which is located in the transitional segment between the stable N-terminal domain and the C-terminal hydrophobic domain. In this study we ask whether the substitution of a proline-containing sequence (PCS) separating other helices in human apoA-I for the non-proline-containing sequence (NPCS) between helices 7 and 8 (residues 184-190) influences HDL subclass association. The human apoA-I mutant with PCS2 replacing NPCS preferentially bound to HDL(2). In contrast, the mutant where PCS3 replaced NPCS preferentially associated with HDL(3). Thus, the specific amino acid sequence between helices 7 and 8 influences HDL subclass association. The wild-type and mutant proteins exhibited similar physicochemical properties except that the two mutants displayed greater lipid-associated stability versus wild-type human apoA-I. These results focus new attention on the influence of the boundary between helices 7 and 8 on the properties of apoA-I. The expression of these mutants in mice may result in the preferential generation of HDL(2) or HDL(3) and allow us to examine experimentally the anti-atherogenicity of the HDL subclasses.

  3. Human Frontal Lobes and AI Planning Systems

    NASA Technical Reports Server (NTRS)

    Levinson, Richard; Lum, Henry Jr. (Technical Monitor)

    1994-01-01

    Human frontal lobes are essential for maintaining a self-regulating balance between predictive and reactive behavior. This paper describes a system that integrates prediction and reaction based on neuropsychological theories of frontal lobe function. In addition to enhancing our understanding of deliberate action in humans' the model is being used to develop and evaluate the same properties in machines. First, the paper presents some background neuropsychology in order to set a general context. The role of frontal lobes is then presented by summarizing three theories which formed the basis for this work. The components of an artificial frontal lobe are then discussed from both neuropsychological and AI perspectives. The paper concludes by discussing issues and methods for evaluating systems that integrate planning and reaction.

  4. On the mechanism of cholesterol interaction with apolipoproteins A-I and E.

    PubMed

    Klimov, A N; Kozhevnikova, K A; Klueva, N N; Belova, E V

    1992-10-01

    It is shown that cholesterol may interact with some substances containing the guanidine group (guanidine itself, arginine, metformin and dodecylguanidine bromide) and with arginine-rich proteins--apoproteins A-I and E. In the latter case the interaction produces the formation of cholesterol-apoprotein complexes. Analysis of such complexes has shown that one apo A-I molecule binds 17-22 and one apo E molecule binds 30-35 sterol molecules, which approximately corresponds to the amount of arginine residues in these proteins. Formation of cholesterol-apoprotein complexes has been suggested to occur due to: (1) formation of hydrogen bond and/or ion-dipole interaction between cholesterol hydroxyl and guanidine groups of the apoprotein arginine residues and (2) hydrophobic interaction of the cholesterol aliphatic chain with nonpolar side chains of the amino acids occupying the third position from arginine in the protein molecule. PMID:1468123

  5. Regulation of apolipoprotein A-I gene expression in Hep G2 cells depleted of Cu by cupruretic tetramine.

    PubMed

    Wu, J Y; Zhang, J J; Wang, Y; Reaves, S K; Wang, Y R; Lei, P P; Lei, K Y

    1997-10-01

    Studies were designed to examine the regulation of apolipoprotein (apo) A-I gene expression in Cu-depleted Hep G2 cells. The cupruretic chelator N,N'-bis(2-aminoethyl)-1,3-propanediamine 4 HCl (2,3,2-tetramine or TETA) was used to maintain a 77% reduction in cellular Cu in Hep G2 cells. After two passages of TETA treatment, the relative abundance of apoA-I mRNA was elevated 52%. In TETA-treated cells, the rate of apoA-I mRNA decay measured by an actinomycin D chase study was accelerated 108%, and the synthesis of apoA-I mRNA determined by a nuclear runoff assay was enhanced 2.5-fold in TETA-treated cells. All of those changes could be reverted toward the control values with Cu supplementation for only 2 days. In transient transfection assays, a 26.7% increase in chloramphenicol O-acetyltransferase (CAT) activity for the reporter construct -256AI-CAT was observed in the treated cells. However, the ability of apoA-I regulatory protein 1 (ARP-1) to repress the CAT activity was not affected by the depressed Cu status. In addition, gel retardation experiments demonstrated that Cu depletion enhanced the binding of hepatocyte nuclear factor 4 (HNF-4) and other undefined nuclear factors to oligonucleotides containing site A, one of three regulatory sites of the apoA-I gene promoter. Moreover, the relative abundance of HNF-4 mRNA was increased 58% in the Cu-depleted cells. Thus the observed increase in apoA-I gene transcription may be mediated mostly by an elevated level of the regulatory factor, HNF-4. In summary, the present findings established the mechanism by which a depressed cellular Cu status can enhance apoA-I mRNA production and subsequently increase apoA-I synthesis. PMID:9357782

  6. Variation at the hepatic lipase and apolipoprotein AI/CIII/AIV loci is a major cause of genetically determined variation in plasma HDL cholesterol levels.

    PubMed Central

    Cohen, J C; Wang, Z; Grundy, S M; Stoesz, M R; Guerra, R

    1994-01-01

    Genetic factors have been shown to play an important role in determining interindividual variation in plasma HDL-C levels, but the specific genetic determinants of HDL cholesterol (HDL-C) levels have not been elucidated. In this study, the effects of variation in the genomic regions encoding hepatic lipase, apolipoprotein AI/CIII/AIV, and the cholesteryl ester transfer protein on plasma HDL-C levels were examined in 73 normotriglyceridemic, Caucasian nuclear families. Genetic factors accounted for 56.5 +/- 13% of the interindividual variation in plasma HDL-C levels. For each candidate gene, adjusted plasma HDL-C levels of sibling pairs who shared zero, one, or two parental alleles identical-by-descent were compared using sibling-pair linkage analysis. Allelic variation in the genes encoding hepatic lipase and apolipoprotein AI/CIII/AIV accounted for 25 and 22%, respectively, of the total interindividual variation in plasma HDL-C levels. In contrast, none of the variation in plasma HDL-C levels could be accounted for by allelic variation in the cholesteryl ester transfer protein. These findings indicate that a major fraction of the genetically determined variation in plasma HDL-C levels is conferred by allelic variation at the hepatic lipase and the apolipoprotein AI/CIII/AIV gene loci. PMID:7989594

  7. High-density Lipoproteins and Apolipoprotein A-I: Potential New Players in the Prevention and Treatment of Lung Disease

    PubMed Central

    Gordon, Elizabeth M.; Figueroa, Debbie M.; Barochia, Amisha V.; Yao, Xianglan; Levine, Stewart J.

    2016-01-01

    Apolipoprotein A-I (apoA-I) and high-density lipoproteins (HDL) mediate reverse cholesterol transport out of cells. Furthermore, HDL has additional protective functions, which include anti-oxidative, anti-inflammatory, anti-apoptotic, and vasoprotective effects. In contrast, HDL can become dysfunctional with a reduction in both cholesterol efflux and anti-inflammatory properties in the setting of disease or the acute phase response. These paradigms are increasingly being recognized to be active in the pulmonary system, where apoA-I and HDL have protective effects in normal lung health, as well as in a variety of disease states, including acute lung injury (ALI), asthma, chronic obstructive pulmonary disease, lung cancer, pulmonary arterial hypertension, pulmonary fibrosis, and viral pneumonia. Similar to observations in cardiovascular disease, however, HDL may become dysfunctional and contribute to disease pathogenesis in respiratory disorders. Furthermore, synthetic apoA-I mimetic peptides have been shown to have protective effects in animal models of ALI, asthma, pulmonary hypertension, and influenza pneumonia. These findings provide evidence to support the concept that apoA-I mimetic peptides might be developed into a new treatment that can either prevent or attenuate the manifestations of lung diseases, such as asthma. Thus, the lung is positioned to take a page from the cardiovascular disease playbook and utilize the protective properties of HDL and apoA-I as a novel therapeutic approach. PMID:27708582

  8. Apolipoprotein B and A-I values in 147576 Swedish males and females, standardized according to the World Health Organization-International Federation of Clinical Chemistry First International Reference Materials.

    PubMed

    Jungner, I; Marcovina, S M; Walldius, G; Holme, I; Kolar, W; Steiner, E

    1998-08-01

    Serum concentrations of apolipoprotein (apo) B and apo A-I were measured from 1985-1996 in a Swedish population sample of 83 112 males and 64 464 females, ages <20 to >80 years, using an automated immunoturbidimetric method calibrated against fresh pools of human serum and commercial calibrators. All values were recalculated in 1997 after calibration against the WHO-IFCC First International Reference Materials. The recalculation factor was 1.059 for apo B, whereas for apo A-I, the correction was: y = 0.989x + 0.101. The total CVs for both apo B and A-I were generally <7%. The mean value (+/- SD) for apo B was 1.31 +/- 0.35 g/L in all males and 1.22 +/- 0.36 g/L in all females. The mean apo A-I concentration was 1.36 +/- 0.22 g/L in males-10% lower than in females (1.51 +/- 0.24 g/L). The mean value of apo B increased up to 60 years of age in males and up to 70 years of age in females. apo A-I concentrations changed only slightly with age in both males and females. apo A-I concentrations among Swedes are nearly identical to those reported recently by two American studies and those obtained in a Finnish population sample. Mean apo B concentrations differ somewhat between the populations but mirror-as expected-differences in total cholesterol concentrations. The highest values were noted in Swedish subjects. The Swedish sample population is, to our knowledge, the largest describing the distribution of apo B and A-I in a general population of adult males and females of all ages determined with procedures standardized and traceable to the WHO-IFCC First International Reference Materials.

  9. Acrolein impairs ATP binding cassette transporter A1-dependent cholesterol export from cells through site-specific modification of apolipoprotein A-I.

    PubMed

    Shao, Baohai; Fu, Xiaoyun; McDonald, Thomas O; Green, Pattie S; Uchida, Koji; O'Brien, Kevin D; Oram, John F; Heinecke, Jay W

    2005-10-28

    Acrolein is a highly reactive alpha,beta-unsaturated aldehyde, but the factors that control its reactions with nucleophilic groups on proteins remain poorly understood. Lipid peroxidation and threonine oxidation by myeloperoxidase are potential sources of acrolein during inflammation. Because both pathways are implicated in atherogenesis and high density lipoprotein (HDL) is anti-atherogenic, we investigated the possibility that acrolein might target the major protein of HDL, apolipoprotein A-I (apoA-I), for modification. Tandem mass spectrometric analysis demonstrated that lysine 226, located near the center of helix 10 in apoA-I, was the major site modified by acrolein. Importantly, this region plays a critical role in the cellular interactions and ability of apoA-I to transport lipid. Indeed, we found that conversion of Lys-226 to N(epsilon)-(3-methylpyridinium)lysine by acrolein associated quantitatively with decreased cholesterol efflux from cells via the ATP-binding cassette transporter A1 pathway. In the crystal structure of truncated apoA-I, Glu-234 lies adjacent to Lys-226, suggesting that negatively charged residues might direct the modification of specific lysine residues in proteins. Finally, immunohistochemical studies with a monoclonal antibody revealed co-localization of apoA-I with acrolein adducts in human atherosclerotic lesions. Our observations suggest that acrolein might interfere with normal reverse cholesterol transport by HDL by modifying specific sites in apoA-I. Thus, acrolein might contribute to atherogenesis by impairing cholesterol removal from the artery wall. PMID:16126721

  10. Amyloidogenic Mutation Promotes Fibril Formation of the N-terminal Apolipoprotein A-I on Lipid Membranes*

    PubMed Central

    Mizuguchi, Chiharu; Ogata, Fuka; Mikawa, Shiho; Tsuji, Kohei; Baba, Teruhiko; Shigenaga, Akira; Shimanouchi, Toshinori; Okuhira, Keiichiro; Otaka, Akira; Saito, Hiroyuki

    2015-01-01

    The N-terminal amino acid 1–83 fragment of apolipoprotein A-I (apoA-I) has a strong propensity to form amyloid fibrils at physiological neutral pH. Because apoA-I has an ability to bind to lipid membranes, we examined the effects of the lipid environment on fibril-forming properties of the N-terminal fragment of apoA-I variants. Thioflavin T fluorescence assay as well as fluorescence and transmission microscopies revealed that upon lipid binding, fibril formation by apoA-I 1–83 is strongly inhibited, whereas the G26R mutant still retains the ability to form fibrils. Such distinct effects of lipid binding on fibril formation were also observed for the amyloidogenic prone region-containing peptides, apoA-I 8–33 and 8–33/G26R. This amyloidogenic region shifts from random coil to α-helical structure upon lipid binding. The G26R mutation appears to prevent this helix transition because lower helical propensity and more solvent-exposed conformation of the G26R variant upon lipid binding were observed in the apoA-I 1–83 fragment and 8–33 peptide. With a partially α-helical conformation induced by the presence of 2,2,2-trifluoroethanol, fibril formation by apoA-I 1–83 was strongly inhibited, whereas the G26R variant can form amyloid fibrils. These findings suggest a new possible pathway for amyloid fibril formation by the N-terminal fragment of apoA-I variants: the amyloidogenic mutations partially destabilize the α-helical structure formed upon association with lipid membranes, resulting in physiologically relevant conformations that allow fibril formation. PMID:26175149

  11. Amyloidogenic Mutation Promotes Fibril Formation of the N-terminal Apolipoprotein A-I on Lipid Membranes.

    PubMed

    Mizuguchi, Chiharu; Ogata, Fuka; Mikawa, Shiho; Tsuji, Kohei; Baba, Teruhiko; Shigenaga, Akira; Shimanouchi, Toshinori; Okuhira, Keiichiro; Otaka, Akira; Saito, Hiroyuki

    2015-08-21

    The N-terminal amino acid 1-83 fragment of apolipoprotein A-I (apoA-I) has a strong propensity to form amyloid fibrils at physiological neutral pH. Because apoA-I has an ability to bind to lipid membranes, we examined the effects of the lipid environment on fibril-forming properties of the N-terminal fragment of apoA-I variants. Thioflavin T fluorescence assay as well as fluorescence and transmission microscopies revealed that upon lipid binding, fibril formation by apoA-I 1-83 is strongly inhibited, whereas the G26R mutant still retains the ability to form fibrils. Such distinct effects of lipid binding on fibril formation were also observed for the amyloidogenic prone region-containing peptides, apoA-I 8-33 and 8-33/G26R. This amyloidogenic region shifts from random coil to α-helical structure upon lipid binding. The G26R mutation appears to prevent this helix transition because lower helical propensity and more solvent-exposed conformation of the G26R variant upon lipid binding were observed in the apoA-I 1-83 fragment and 8-33 peptide. With a partially α-helical conformation induced by the presence of 2,2,2-trifluoroethanol, fibril formation by apoA-I 1-83 was strongly inhibited, whereas the G26R variant can form amyloid fibrils. These findings suggest a new possible pathway for amyloid fibril formation by the N-terminal fragment of apoA-I variants: the amyloidogenic mutations partially destabilize the α-helical structure formed upon association with lipid membranes, resulting in physiologically relevant conformations that allow fibril formation.

  12. The A's Have It: Developing Apolipoprotein A-I Mimetic Peptides Into a Novel Treatment for Asthma.

    PubMed

    Yao, Xianglan; Gordon, Elizabeth M; Barochia, Amisha V; Remaley, Alan T; Levine, Stewart J

    2016-08-01

    New treatments are needed for patients with asthma who are refractory to standard therapies, such as individuals with a phenotype of "type 2-low" inflammation. This important clinical problem could potentially be addressed by the development of apolipoprotein A-I (apoA-I) mimetic peptides. ApoA-I interacts with its cellular receptor, the ATP-binding cassette subfamily A, member 1 (ABCA1), to facilitate cholesterol efflux out of cells to form nascent high-density lipoprotein particles. The ability of the apoA-I/ABCA1 pathway to promote cholesterol efflux from cells that mediate adaptive immunity, such as antigen-presenting cells, can attenuate their function. Data from experimental murine models have shown that the apoA-I/ABCA1 pathway can reduce neutrophilic airway inflammation, primarily by suppressing the production of granulocyte-colony stimulating factor. Furthermore, administration of apoA-I mimetic peptides to experimental murine models of allergic asthma has decreased both neutrophilic and eosinophilic airway inflammation, as well as airway hyperresponsiveness and mucous cell metaplasia. Higher serum levels of apoA-I have also been associated with less severe airflow obstruction in patients with asthma. Collectively, these results suggest that the apoA-I/ABCA1 pathway may have a protective effect in asthma, and support the concept of advancing inhaled apoA-I mimetic peptides to clinical trials that can assess their safety and effectiveness. Thus, we propose that the development of inhaled apoA-I mimetic peptides as a new treatment could represent a clinical advance for patients with severe asthma who are unresponsive to other therapies.

  13. Mycoplasma gallisepticum (HS strain) surface lipoprotein pMGA interacts with host apolipoprotein A-I during infection in chicken.

    PubMed

    Hu, Fuli; Zhao, Chengcheng; Bi, Dingren; Tian, Wei; Chen, Jiao; Sun, Jianjun; Peng, Xiuli

    2016-02-01

    The adhesin protein from Mycoplasma gallisepticum (HS strain), namely pMGA1.2, is required for M. gallisepticum (MG) infection in chicken. However, the host factor(s) that interact with pMGA1.2 is not known. In this study, we prepared the membrane fraction of trachea epithelial cells from chicken embryos. Using an improved virus overlay protein blot assay (VOPBA) and glutathione S-transferase (GST) pull-down assay, we found that pMGA1.2 specifically bound to a ∼30 kDa host protein. This host protein was further identified by mass spectrometry as chicken apolipoprotein A-I (ApoA-I). We expressed and purified the recombinant ApoA-I protein in Escherichia coli and confirmed that it bound to the purified pMGA1.2 protein in vitro. Transiently expressed pMGA1.2 and ApoA-I were colocalized in HeLa cells. Finally, we designed small interfering RNA (siRNA) molecules to knock down the expression of either ApoA-I or pMGA1.2, which inhibited the MG-induced cell cycle disruption in cells of chicken embryo fibroblast cell line (DF-1). Similarly, knockdown of ApoA-I inhibited the cilia loss and damage in chicken trachea cells in MG infection. In summary, ApoA-I may be an essential host factor in MG infection through interacting with pMGA1.2.

  14. Conservation of apolipoprotein A-I's central domain structural elements upon lipid association on different high-density lipoprotein subclasses.

    PubMed

    Oda, Michael N; Budamagunta, Madhu S; Geier, Ethan G; Chandradas, Sajiv H; Shao, Baohai; Heinecke, Jay W; Voss, John C; Cavigiolio, Giorgio

    2013-10-01

    The antiatherogenic properties of apolipoprotein A-I (apoA-I) are derived, in part, from lipidation-state-dependent structural elements that manifest at different stages of apoA-I's progression from lipid-free protein to spherical high-density lipoprotein (HDL). Previously, we reported the structure of apoA-I's N-terminus on reconstituted HDLs (rHDLs) of different sizes. We have now investigated at the single-residue level the conformational adaptations of three regions in the central domain of apoA-I (residues 119-124, 139-144, and 164-170) upon apoA-I lipid binding and HDL formation. An important function associated with these residues of apoA-I is the activation of lecithin:cholesterol acyltransferase (LCAT), the enzyme responsible for catalyzing HDL maturation. Structural examination was performed by site-directed tryptophan fluorescence and spin-label electron paramagnetic resonance spectroscopies for both the lipid-free protein and rHDL particles 7.8, 8.4, and 9.6 nm in diameter. The two methods provide complementary information about residue side chain mobility and molecular accessibility, as well as the polarity of the local environment at the targeted positions. The modulation of these biophysical parameters yielded new insight into the importance of structural elements in the central domain of apoA-I. In particular, we determined that the loosely lipid-associated structure of residues 134-145 is conserved in all rHDL particles. Truncation of this region completely abolished LCAT activation but did not significantly affect rHDL size, reaffirming the important role of this structural element in HDL function. PMID:23984834

  15. Deficiency in apolipoprotein A-I ablates the pharmacological effects of metformin on plasma glucose homeostasis and hepatic lipid deposition.

    PubMed

    Karavia, Eleni A; Hatziri, Aikaterini; Kalogeropoulou, Christina; Papachristou, Nikolaos I; Xepapadaki, Eva; Constantinou, Caterina; Natsos, Anastasios; Petropoulou, Peristera-Ioanna; Sasson, Shlomo; Papachristou, Dionysios J; Kypreos, Kyriakos E

    2015-11-01

    Recently, we showed that deficiency in apolipoprotein A-I (ApoA-I) sensitizes mice to diet-induced obesity, glucose intolerance and NAFLD. Here we investigated the potential involvement of ApoA-I in the pharmacological effects of metformin on glucose intolerance and NAFLD development. Groups of apoa1-deficient (apoa1(-/-)) and C57BL/6 mice fed western-type diet were either treated with a daily dose of 300 mg/kg metformin for 18 weeks or left untreated for the same period. Then, histological and biochemical analyses were performed. Metformin treatment led to a comparable reduction in plasma insulin levels in both C57BL/6 and apoa1(-/-) mice following intraperitoneal glucose tolerance test. However, only metformin-treated C57BL/6 mice maintained sufficient peripheral insulin sensitivity to effectively clear glucose following the challenge, as indicated by a [(3)H]-2-deoxy-D-glucose uptake assay in isolated soleus muscle. Similarly, deficiency in ApoA-I ablated the effect of metformin on hepatic lipid deposition and NAFLD development. Gene expression analysis indicated that the effects of ApoA-I on metformin treatment may be independent of adenosine monophosphate-activated protein kinase (AMPK) activation and de novo lipogenesis. Interestingly, metformin treatment reduced mitochondrial oxidative phosphorylation function only in apoa1(-/-) mice. Our data show that the role of ApoA-I in diabetes extends to the modulation of the pharmacological actions of metformin, a common drug for the treatment of type 2 diabetes.

  16. Cellular interaction and cytotoxicity of the iowa mutation of apolipoprotein A-I (ApoA-IIowa) amyloid mediated by sulfate moieties of heparan sulfate.

    PubMed

    Kuwabara, Kaori; Nishitsuji, Kazuchika; Uchimura, Kenji; Hung, Shang-Cheng; Mizuguchi, Makoto; Nakajima, Hiroyuki; Mikawa, Shiho; Kobayashi, Norihiro; Saito, Hiroyuki; Sakashita, Naomi

    2015-10-01

    The single amino acid mutation G26R in human apolipoprotein A-I (apoA-I) is associated with familial amyloid polyneuropathy III. ApoA-I carrying this mutation (apoA-IIowa) forms amyloid fibrils in vitro. Heparan sulfate (HS) is a glycosaminoglycan that is abundant at the cell surface and in the extracellular matrix. Although HS and its highly sulfated domains are involved in aggregation of amyloid-β and accumulate in cerebral amyloid plaques of patients with Alzheimer disease and mouse models of this disease, the role of HS in familial amyloid polyneuropathy III has never been addressed. Here, we used cell models to investigate the possible role of HS in the cytotoxicity of apoA-IIowa amyloid. Wild-type CHO cells, but not pgsD-677 cells, an HS-deficient CHO mutant, demonstrated uptake of apoA-IIowa amyloid after incubation with the amyloid. Addition of sulfated glycosaminoglycans to culture media prevented interaction with and cytotoxicity of apoA-IIowa amyloid to CHO cells. Elimination of cell surface HS or inhibition of HS sulfation with chemical reagents interfered with interaction of apoA-IIowa amyloid with CHO cells. We also found that cellular interaction and cytotoxicity of apoA-IIowa amyloid were significantly attenuated in CHO cells that stably expressed the human extracellular endoglucosamine 6-sulfatases HSulf-1 and HSulf-2. Our results thus suggest that cell surface HS mediates cytotoxicity of apoA-IIowa amyloid and that enzymatic remodeling of HS mitigates the cytotoxicity.

  17. PPARγ Represses Apolipoprotein A-I Gene but Impedes TNFα-Mediated ApoA-I Downregulation in HepG2 Cells.

    PubMed

    Shavva, Vladimir S; Mogilenko, Denis A; Bogomolova, Alexandra M; Nikitin, Artemy A; Dizhe, Ella B; Efremov, Alexander M; Oleinikova, Galina N; Perevozchikov, Andrej P; Orlov, Sergey V

    2016-09-01

    Apolipoprotein A-I (ApoA-I) is the main anti-atherogenic component of human high-density lipoproteins (HDL). ApoA-I gene expression is regulated by several nuclear receptors, which are the sensors for metabolic changes during development of cardiovascular diseases. Activation of nuclear receptor PPARγ has been shown to impact lipid metabolism as well as inflammation. Here, we have shown that synthetic PPARγ agonist GW1929 decreases both ApoA-I mRNA and protein levels in HepG2 cells and the effect of GW1929 on apoA-I gene transcription depends on PPARγ. PPARγ binds to the sites A and C within the hepatic enhancer of apoA-I gene and the negative regulation of apoA-I gene transcription by PPARγ appears to be realized via the site C (-134 to -119). Ligand activation of PPARγ leads to an increase of LXRβ and a decrease of PPARα binding to the apoA-I gene hepatic enhancer in HepG2 cells. GW1929 abolishes the TNFα-mediated decrease of ApoA-I mRNA expression in both HepG2 and Caco-2 cells but does not block TNFα-mediated inhibition of ApoA-I protein secretion by HepG2 cells. These data demonstrate that complex of PPARγ with GW1929 is a negative regulator involved in the control of ApoA-I expression and secretion in human hepatocyte- and enterocyte-like cells. J. Cell. Biochem. 117: 2010-2022, 2016. © 2016 Wiley Periodicals, Inc.

  18. Apolipoprotein A-I mimetic peptide 4F blocks sphingomyelinase-induced LDL aggregation.

    PubMed

    Nguyen, Su Duy; Javanainen, Matti; Rissanen, Sami; Zhao, Hongxia; Huusko, Jenni; Kivelä, Annukka M; Ylä-Herttuala, Seppo; Navab, Mohamad; Fogelman, Alan M; Vattulainen, Ilpo; Kovanen, Petri T; Öörni, Katariina

    2015-06-01

    Lipolytic modification of LDL particles by SMase generates LDL aggregates with a strong affinity for human arterial proteoglycans and may so enhance LDL retention in the arterial wall. Here, we evaluated the effects of apoA-I mimetic peptide 4F on structural and functional properties of the SMase-modified LDL particles. LDL particles with and without 4F were incubated with SMase, after which their aggregation, structure, and proteoglycan binding were analyzed. At a molar ratio of L-4F to apoB-100 of 2.5 to 20:1, 4F dose-dependently inhibited SMase-induced LDL aggregation. At a molar ratio of 20:1, SMase-induced aggregation was fully blocked. Binding of 4F to LDL particles inhibited SMase-induced hydrolysis of LDL by 10% and prevented SMase-induced LDL aggregation. In addition, the binding of the SMase-modified LDL particles to human aortic proteoglycans was dose-dependently inhibited by pretreating LDL with 4F. The 4F stabilized apoB-100 conformation and inhibited SMase-induced conformational changes of apoB-100. Molecular dynamic simulations showed that upon binding to protein-free LDL surface, 4F locally alters membrane order and fluidity and induces structural changes to the lipid layer. Collectively, 4F stabilizes LDL particles by preventing the SMase-induced conformational changes in apoB-100 and so blocks SMase-induced LDL aggregation and the resulting increase in LDL retention.

  19. Anti-CD20 single chain variable antibody fragment-apolipoprotein A-I chimera containing nanodisks promote targeted bioactive agent delivery to CD20-positive lymphomas.

    PubMed

    Crosby, Natasha M; Ghosh, Mistuni; Su, Betty; Beckstead, Jennifer A; Kamei, Ayako; Simonsen, Jens B; Luo, Bing; Gordon, Leo I; Forte, Trudy M; Ryan, Robert O

    2015-08-01

    A fusion protein comprising an α-CD20 single chain variable fragment (scFv) antibody, a spacer peptide, and human apolipoprotein (apo) A-I was constructed and expressed in Escherichia coli. The lipid interaction properties intrinsic to apoA-I as well as the antigen recognition properties of the scFv were retained by the chimera. scFv•apoA-I was formulated into nanoscale reconstituted high-density lipoprotein particles (termed nanodisks; ND) and incubated with cultured cells. α-CD20 scFv•apoA-I ND bound to CD20-positive non-Hodgkins lymphoma (NHL) cells (Ramos and Granta) but not to CD20-negative T lymphocytes (i.e., Jurkat). Binding to NHL cells was partially inhibited by pre-incubation with rituximab, a monoclonal antibody directed against CD20. Confocal fluorescence microscopy analysis of Granta cells following incubation with α-CD20 scFv•apoA-I ND formulated with the intrinsically fluorescent hydrophobic polyphenol, curcumin, revealed α-CD20 scFv•apoA-I localizes to the cell surface, while curcumin off-loads and gains entry to the cell. Compared to control incubations, viability of cultured NHL cells was decreased upon incubation with α-CD20 scFv•apoA-I ND harboring curcumin. Thus, formulation of curcumin ND with α-CD20 scFv•apoA-I as the scaffold component confers cell targeting and enhanced bioactive agent delivery, providing a strategy to minimize toxicity associated with chemotherapeutic agents.

  20. Anti-CD20 single chain variable antibody fragment-apolipoprotein A-I chimera containing nanodisks promote targeted bioactive agent delivery to CD20-positive lymphomas.

    PubMed

    Crosby, Natasha M; Ghosh, Mistuni; Su, Betty; Beckstead, Jennifer A; Kamei, Ayako; Simonsen, Jens B; Luo, Bing; Gordon, Leo I; Forte, Trudy M; Ryan, Robert O

    2015-08-01

    A fusion protein comprising an α-CD20 single chain variable fragment (scFv) antibody, a spacer peptide, and human apolipoprotein (apo) A-I was constructed and expressed in Escherichia coli. The lipid interaction properties intrinsic to apoA-I as well as the antigen recognition properties of the scFv were retained by the chimera. scFv•apoA-I was formulated into nanoscale reconstituted high-density lipoprotein particles (termed nanodisks; ND) and incubated with cultured cells. α-CD20 scFv•apoA-I ND bound to CD20-positive non-Hodgkins lymphoma (NHL) cells (Ramos and Granta) but not to CD20-negative T lymphocytes (i.e., Jurkat). Binding to NHL cells was partially inhibited by pre-incubation with rituximab, a monoclonal antibody directed against CD20. Confocal fluorescence microscopy analysis of Granta cells following incubation with α-CD20 scFv•apoA-I ND formulated with the intrinsically fluorescent hydrophobic polyphenol, curcumin, revealed α-CD20 scFv•apoA-I localizes to the cell surface, while curcumin off-loads and gains entry to the cell. Compared to control incubations, viability of cultured NHL cells was decreased upon incubation with α-CD20 scFv•apoA-I ND harboring curcumin. Thus, formulation of curcumin ND with α-CD20 scFv•apoA-I as the scaffold component confers cell targeting and enhanced bioactive agent delivery, providing a strategy to minimize toxicity associated with chemotherapeutic agents. PMID:25994015

  1. Apolipoprotein A-I Deficiency Increases Cerebral Amyloid Angiopathy and Cognitive Deficits in APP/PS1ΔE9 Mice*

    PubMed Central

    Lefterov, Iliya; Fitz, Nicholas F.; Cronican, Andrea A.; Fogg, Allison; Lefterov, Preslav; Kodali, Ravindra; Wetzel, Ronald; Koldamova, Radosveta

    2010-01-01

    A hallmark of Alzheimer disease (AD) is the deposition of amyloid β (Aβ) in brain parenchyma and cerebral blood vessels, accompanied by cognitive decline. Previously, we showed that human apolipoprotein A-I (apoA-I) decreases Aβ40 aggregation and toxicity. Here we demonstrate that apoA-I in lipidated or non-lipidated form prevents the formation of high molecular weight aggregates of Aβ42 and decreases Aβ42 toxicity in primary brain cells. To determine the effects of apoA-I on AD phenotype in vivo, we crossed APP/PS1ΔE9 to apoA-IKO mice. Using a Morris water maze, we demonstrate that the deletion of mouse Apoa-I exacerbates memory deficits in APP/PS1ΔE9 mice. Further characterization of APP/PS1ΔE9/apoA-IKO mice showed that apoA-I deficiency did not affect amyloid precursor protein processing, soluble Aβ oligomer levels, Aβ plaque load, or levels of insoluble Aβ in brain parenchyma. To examine the effect of Apoa-I deletion on cerebral amyloid angiopathy, we measured insoluble Aβ isolated from cerebral blood vessels. Our data show that in APP/PS1ΔE9/apoA-IKO mice, insoluble Aβ40 is increased more than 10-fold, and Aβ42 is increased 1.5-fold. The increased levels of deposited amyloid in the vessels of cortices and hippocampi of APP/PS1ΔE9/apoA-IKO mice, measured by X-34 staining, confirmed the results. Finally, we demonstrate that lipidated and non-lipidated apoA-I significantly decreased Aβ toxicity against brain vascular smooth muscle cells. We conclude that lack of apoA-I aggravates the memory deficits in APP/PS1ΔE9 mice in parallel to significantly increased cerebral amyloid angiopathy. PMID:20739292

  2. Anti-CD20 single chain variable antibody fragment–apolipoprotein A-I chimera containing nanodisks promote targeted bioactive agent delivery to CD20-positive lymphomas

    PubMed Central

    Crosby, Natasha M.; Ghosh, Mistuni; Su, Betty; Beckstead, Jennifer A.; Kamei, Ayako; Simonsen, Jens B.; Luo, Bing; Gordon, Leo I.; Forte, Trudy M.; Ryan, Robert O.

    2015-01-01

    A fusion protein comprising an α-CD20 single chain variable fragment (scFv) antibody, a spacer peptide, and human apolipoprotein (apo) A-I was constructed and expressed in Escherichia coli. The lipid interaction properties intrinsic to apoA-I as well as the antigen recognition properties of the scFv were retained by the chimera. scFv•apoA-I was formulated into nanoscale reconstituted high-density lipoprotein particles (termed nanodisks; ND) and incubated with cultured cells. α-CD20 scFv•apoA-I ND bound to CD20-positive non-Hodgkins lymphoma (NHL) cells (Ramos and Granta) but not to CD20-negative T lymphocytes (i.e., Jurkat). Binding to NHL cells was partially inhibited by pre-incubation with rituximab, a monoclonal antibody directed against CD20. Confocal fluorescence microscopy analysis of Granta cells following incubation with α-CD20 scFv•apoA-I ND formulated with the intrinsically fluorescent hydrophobic polyphenol, curcumin, revealed α-CD20 scFv•apoA-I localizes to the cell surface, while curcumin off-loads and gains entry to the cell. Compared to control incubations, viability of cultured NHL cells was decreased upon incubation with α-CD20 scFv•apoA-I ND harboring curcumin. Thus, formulation of curcumin ND with α-CD20 scFv•apoA-I as the scaffold component confers cell targeting and enhanced bioactive agent delivery, providing a strategy to minimize toxicity associated with chemotherapeutic agents. PMID:25994015

  3. Lipids and apolipoproteins A-I, B and C-II and different rapid weight loss programs (weight lifters, wrestlers, boxers and judokas).

    PubMed

    Jauhiainen, M; Laitinen, M; Penttilä, I; Nousiainen, U; Ahonen, E

    1985-01-01

    Apolipoproteins A-I, B, C-II and lipids were studied before and after rapid weight loss schedules. The compared groups were all athletic. Apolipoproteins were determined by electroimmunoassay methods using apoproteins purified by chromatofocusing column method. Dextran T10 was shown to increase rocket height in ApoB assay. Over 1% Dextran concentrations gave poor response. The linearity during calibration was from 0.3 to 3.0 g ApoB/l. Baseline values of ApoA-I in wrestlers, weightlifters, boxers and judokas were slightly higher as compared to "normal" population; ApoB was clearly reduced (mean value of 690 mg/l). Weight-loss was significant in each experimental group; mean value of 4.1% in active exercise, sauna and diuretic groups together. Compared as the whole sportsmen group in passive weight loss (or sauna) and diuretic groups the most pronounced changes were seen to be elevated apoprotein concentrations, whereas weight-loss by active rapid exercise resulted no apoprotein changes, but instead an increment in HDL cholesterol and decrement in triglycerides, respectively. The present study was the first to evaluate baseline values of apoproteins A-I, B and C-II in first class athletes and also the possible changes in these and lipid values in rapid weight-loss practices.

  4. Composition, structure and substrate properties of reconstituted discoidal HDL with apolipoprotein A-I and cholesteryl ester

    NASA Astrophysics Data System (ADS)

    Dergunov, Alexander D.; Shabrova, Elena V.; Dobretsov, Gennady E.

    2010-03-01

    To investigate the influence of lipid unsaturation and neutral lipid on the maturation of high density lipoproteins, the discoidal complexes of apoA-I, phosphatidylcholine and cholesteryl ester (CE) were prepared. Saturated dipalmitoylphosphatidylcholine (DPPC) and unsaturated palmitoyllinoleoylphosphatidylcholine (PLPC), palmitoyloleoylphosphatidylcholine (POPC), and fluorescent probe cholesteryl 1-pyrenedecanoate (CPD) that forms in a diffusion- and concentration-dependent manner short-lived dimer of unexcited and excited molecules (excimer) were used. The apoA-I/DPPC/CPD complexes were heterogeneous by size, composition and probe location. CPD molecules incorporated more efficiently into larger complexes and accumulated in a central part of the discs. The apoA-I/POPC(PLPC)/CPD were also heterogeneous, however, probe molecules distributed preferentially into smaller complexes and accumulated at disc periphery. The kinetics of CPD transfer by recombinant cholesteryl ester transfer protein (CETP) to human plasma LDL is well described by two-exponential decay, the fast component with a shorter transfer time being more populated in PLPC compared to DPPC complexes. The presence of CE molecules in discoidal HDL results in particle heterogeneity. ApoA-I influences the CETP activity modulating the properties of apolipoprotein-phospholipid interface. This may include CE molecules accumulation in the boundary lipid in unsaturated phosphatidylcholine and cluster formation in the bulk bilayer in saturated phosphatidylcholine.

  5. Serum Apolipoprotein A-I and Large High-Density Lipoprotein Particles Are Positively Correlated with FEV1 in Atopic Asthma

    PubMed Central

    Kaler, Maryann; Cuento, Rosemarie A.; Gordon, Elizabeth M.; Weir, Nargues A.; Sampson, Maureen; Fontana, Joseph R.; MacDonald, Sandra; Moss, Joel; Manganiello, Vincent; Remaley, Alan T.; Levine, Stewart J.

    2015-01-01

    Rationale: Although lipids, apolipoproteins, and lipoprotein particles are important modulators of inflammation, varying relationships exist between these parameters and asthma. Objectives: To determine whether serum lipids and apolipoproteins correlate with the severity of airflow obstruction in subjects with atopy and asthma. Methods: Serum samples were obtained from 154 atopic and nonatopic subjects without asthma, and 159 subjects with atopy and asthma. Serum lipid and lipoprotein levels were quantified using standard diagnostic assays and nuclear magnetic resonance (NMR) spectroscopy. Airflow obstruction was assessed by FEV1% predicted. Measurements and Main Results: Serum lipid levels correlated with FEV1 only in the subjects with atopy and asthma. Serum levels of high-density lipoprotein (HDL) cholesterol and apolipoprotein A-I (apoA-I) were positively correlated with FEV1 in subjects with atopy and asthma, whereas a negative correlation existed between FEV1 and serum levels of triglycerides, low-density lipoprotein (LDL) cholesterol, apolipoprotein B (apoB), and the apoB/apoA-I ratio. NMR spectroscopy identified a positive correlation between FEV1 and HDLNMR particle size, as well as the concentrations of large HDLNMR particles and total IDLNMR (intermediate-density lipoprotein) particles in subjects with atopy and asthma. In contrast, LDLNMR particle size and concentrations of LDLNMR and VLDLNMR (very-low-density lipoprotein) particles were negatively correlated with FEV1 in subjects with atopy and asthma. Conclusions: In subjects with atopy and asthma, serum levels of apoA-I and large HDLNMR particles are positively correlated with FEV1, whereas serum triglycerides, LDL cholesterol, and apoB are associated with more severe airflow obstruction. These results may facilitate future studies to assess whether apoA-I and large HDLNMR particles can reduce airflow obstruction and disease severity in asthma. PMID:25692941

  6. Concomitant Effects of Ramadan Fasting and Time-Of-Day on Apolipoprotein AI, B, Lp-a and Homocysteine Responses during Aerobic Exercise in Tunisian Soccer Players

    PubMed Central

    Hammouda, Omar; Chtourou, Hamdi; Aloui, Asma; Chahed, Henda; Kallel, Choumous; Miled, Abdelhedi; Chamari, Karim; Chaouachi, Anis; Souissi, Nizar

    2013-01-01

    Objective To examine the time-of-day and Ramadan fasting (RF) effects on serum apolipoprotein-AI (Apo-AI) and B (Apo-B), lipoprotein particles-a (Lp-a), high-sensitive C-reactive-protein (hs-CRP), and homocysteine (Hcy) during the Yo-Yo intermittent recovery test (YYIRT). Design Performance and biochemical measures were completed at two times-of-day (07:00 and 17:00 h), 1-week before RF (BR), the second week of RF (SWR), and the fourth week of RF (ER). Setting For each session, subjects performed the YYIRT, and blood samples were taken before and 3-min after the test for biochemical measures. Participants Fifteen soccer players. Main Outcome Measures Total distance during the YYIRT, core temperature, body composition, dietary intakes, lipid (HDL-C, LDL-C, Apo-AI, B and Lp-a) and inflammatory (hs-CRP and Hcy) profiles. Results Performances during the YYIRT were higher in the evening than the morning BR (P < 0.05), but this fluctuation was not observed during RF. Moreover, LDL-C, ApoB, and Lp-a were stable throughout the daytime BR. However, during RF, they decreased at 17:00 h (P < 0.05). Likewise, HDL-C and Apo-AI increased after the exercise and were higher at 17:00 h BR (P < 0.001). Moreover, these parameters increased during RF (P < 0.01). Furthermore, Hcy and hs-CRP increased during the exercise (P < 0.01) with higher evening levels BR. During ER, the diurnal pattern of Hcy was inversed (P < 0.001). Conclusions This study concluded that caloric restriction induced by RF seems to ameliorate lipid and inflammatory markers of cardiovascular health during intermittent exercise performed in the evening. PMID:24244572

  7. Myeloperoxidase-derived oxidants modify apolipoprotein A-I and generate dysfunctional high-density lipoproteins: comparison of hypothiocyanous acid (HOSCN) with hypochlorous acid (HOCl).

    PubMed

    Hadfield, Katrina A; Pattison, David I; Brown, Bronwyn E; Hou, Liming; Rye, Kerry-Anne; Davies, Michael J; Hawkins, Clare L

    2013-01-15

    Oxidative modification of HDLs (high-density lipoproteins) by MPO (myeloperoxidase) compromises its anti-atherogenic properties, which may contribute to the development of atherosclerosis. Although it has been established that HOCl (hypochlorous acid) produced by MPO targets apoA-I (apolipoprotein A-I), the major apolipoprotein of HDLs, the role of the other major oxidant generated by MPO, HOSCN (hypothiocyanous acid), in the generation of dysfunctional HDLs has not been examined. In the present study, we characterize the structural and functional modifications of lipid-free apoA-I and rHDL (reconstituted discoidal HDL) containing apoA-I complexed with phospholipid, induced by HOSCN and its decomposition product, OCN- (cyanate). Treatment of apoA-I with HOSCN resulted in the oxidation of tryptophan residues, whereas OCN- induced carbamylation of lysine residues to yield homocitrulline. Tryptophan residues were more readily oxidized on apoA-I contained in rHDLs. Exposure of lipid-free apoA-I to HOSCN and OCN- significantly reduced the extent of cholesterol efflux from cholesterol-loaded macrophages when compared with unmodified apoA-I. In contrast, HOSCN did not affect the anti-inflammatory properties of rHDL. The ability of HOSCN to impair apoA-I-mediated cholesterol efflux may contribute to the development of atherosclerosis, particularly in smokers who have high plasma levels of SCN- (thiocyanate). PMID:23088652

  8. A human apolipoprotein E mimetic peptide reduces atherosclerosis in aged apolipoprotein E null mice

    PubMed Central

    Xu, Yanyong; Liu, Hongmei; Liu, Mengting; Li, Feifei; Liu, Liangchen; Du, Fen; Fan, Daping; Yu, Hong

    2016-01-01

    Apolipoprotein E (apoE) is well known as an antiatherogenic protein via regulating lipid metabolism and inflammation. We previously reported that a human apoE mimetic peptide, EpK, reduced atherosclerosis in apoE null (apoE-/-) mice through reducing inflammation without affecting plasma lipid levels. Here, we construct another human apoE mimetic peptide, named hEp, and investigate whether expression of hEp can reduce atherosclerotic lesion development in aged female apoE-/- mice with pre-existing lesions. We found that chemically synthesized hEp significantly decreased cholesterol accumulation induced by oxidized low density lipoprotein and the expression of inflammatory cytokines TNFα and IL-6 induced by lipopolysaccharide in macrophages. In an in vivo study, Lv-hEp-GFP lentiviruses were intravenously injected into 9 month-old apoE-/- mice. Mice were then fed a chow diet for 18 weeks. Results showed that in comparison to the Lv-GFP lentivirus injection (Lv-GFP) group, Lv-hEp-GFP lentivirus injection achieved hepatic hEp expression and secretion in apoE-/- mice. It was observed that hEp expression significantly reduced plasma VLDL and LDL cholesterol levels and decreased aortic atherosclerotic lesions. This was accompanied by an increase of LDL receptor expression and a reduction of TNFα and IL-6 mRNA levels in the liver. Moreover, expression of hEp increased plasma paraoxonase-1 activity and decreased plasma myeloperoxidase activity and serum amyloid A levels. Our study provides evidence that hEp may be developed as a promising therapeutic apoE mimetic peptide for atherosclerosis-related cardiovascular diseases through its induction of plasma VLDL/LDL cholesterol clearance as well as its anti-oxidative and anti-inflammatory activities.

  9. A human apolipoprotein E mimetic peptide reduces atherosclerosis in aged apolipoprotein E null mice.

    PubMed

    Xu, Yanyong; Liu, Hongmei; Liu, Mengting; Li, Feifei; Liu, Liangchen; Du, Fen; Fan, Daping; Yu, Hong

    2016-01-01

    Apolipoprotein E (apoE) is well known as an antiatherogenic protein via regulating lipid metabolism and inflammation. We previously reported that a human apoE mimetic peptide, EpK, reduced atherosclerosis in apoE null (apoE(-/-)) mice through reducing inflammation without affecting plasma lipid levels. Here, we construct another human apoE mimetic peptide, named hEp, and investigate whether expression of hEp can reduce atherosclerotic lesion development in aged female apoE(-/-) mice with pre-existing lesions. We found that chemically synthesized hEp significantly decreased cholesterol accumulation induced by oxidized low density lipoprotein and the expression of inflammatory cytokines TNFα and IL-6 induced by lipopolysaccharide in macrophages. In an in vivo study, Lv-hEp-GFP lentiviruses were intravenously injected into 9 month-old apoE(-/-) mice. Mice were then fed a chow diet for 18 weeks. Results showed that in comparison to the Lv-GFP lentivirus injection (Lv-GFP) group, Lv-hEp-GFP lentivirus injection achieved hepatic hEp expression and secretion in apoE(-/-) mice. It was observed that hEp expression significantly reduced plasma VLDL and LDL cholesterol levels and decreased aortic atherosclerotic lesions. This was accompanied by an increase of LDL receptor expression and a reduction of TNFα and IL-6 mRNA levels in the liver. Moreover, expression of hEp increased plasma paraoxonase-1 activity and decreased plasma myeloperoxidase activity and serum amyloid A levels. Our study provides evidence that hEp may be developed as a promising therapeutic apoE mimetic peptide for atherosclerosis-related cardiovascular diseases through its induction of plasma VLDL/LDL cholesterol clearance as well as its anti-oxidative and anti-inflammatory activities. PMID:27648138

  10. A human apolipoprotein E mimetic peptide reduces atherosclerosis in aged apolipoprotein E null mice

    PubMed Central

    Xu, Yanyong; Liu, Hongmei; Liu, Mengting; Li, Feifei; Liu, Liangchen; Du, Fen; Fan, Daping; Yu, Hong

    2016-01-01

    Apolipoprotein E (apoE) is well known as an antiatherogenic protein via regulating lipid metabolism and inflammation. We previously reported that a human apoE mimetic peptide, EpK, reduced atherosclerosis in apoE null (apoE-/-) mice through reducing inflammation without affecting plasma lipid levels. Here, we construct another human apoE mimetic peptide, named hEp, and investigate whether expression of hEp can reduce atherosclerotic lesion development in aged female apoE-/- mice with pre-existing lesions. We found that chemically synthesized hEp significantly decreased cholesterol accumulation induced by oxidized low density lipoprotein and the expression of inflammatory cytokines TNFα and IL-6 induced by lipopolysaccharide in macrophages. In an in vivo study, Lv-hEp-GFP lentiviruses were intravenously injected into 9 month-old apoE-/- mice. Mice were then fed a chow diet for 18 weeks. Results showed that in comparison to the Lv-GFP lentivirus injection (Lv-GFP) group, Lv-hEp-GFP lentivirus injection achieved hepatic hEp expression and secretion in apoE-/- mice. It was observed that hEp expression significantly reduced plasma VLDL and LDL cholesterol levels and decreased aortic atherosclerotic lesions. This was accompanied by an increase of LDL receptor expression and a reduction of TNFα and IL-6 mRNA levels in the liver. Moreover, expression of hEp increased plasma paraoxonase-1 activity and decreased plasma myeloperoxidase activity and serum amyloid A levels. Our study provides evidence that hEp may be developed as a promising therapeutic apoE mimetic peptide for atherosclerosis-related cardiovascular diseases through its induction of plasma VLDL/LDL cholesterol clearance as well as its anti-oxidative and anti-inflammatory activities. PMID:27648138

  11. The human apolipoprotein AII gene: structural organization and sites of expression.

    PubMed Central

    Knott, T J; Wallis, S C; Robertson, M E; Priestley, L M; Urdea, M; Rall, L B; Scott, J

    1985-01-01

    The complete nucleotide sequence of the human apolipoprotein All gene together with 911 bases of 5' flanking sequence and 687 bases of 3' flanking sequence have been determined. The mRNA coding region is interrupted by three introns of 169, 293 and 395bp. The Intro-exon structure of the apo All gene is similar to that of the apo AI, apo CIII and apo E genes: three introns separate 4 coding sequences specifying the 5' untranslated region, pre-peptide, a short N-terminal domain and a C-terminal domain composed of a variable number of lipid-binding amphipathic helices. Intron II carries a 33bp dG-dT repetitive element adjacent to the 3' splice junction which has the potential to adopt the Z-DNA conformation. The 5' and 3' terminuses of the mRNA have been identified by primer extension and S1 nuclease mapping. A number of short direct repeats are found in the 5' flanking region and an inverted repeat occurs between the CAAT and TATA boxes. Downstream of the the gene is an Alu family repeat containing a polymorphic MspI site, the deletion of which is associated with increased circulating levels of apoAII. ApoAII gene expression was demonstrated in adult human liver and HepG2 cells but not in human small intestine. Of ten Rhesus monkey tissues examined apo All mRNA was detected only in liver. Images PMID:2995928

  12. Effect of weight loss, independent of change in diet composition, on apolipoprotein AI kinetic in men with metabolic syndrome.

    PubMed

    Richard, Caroline; Couture, Patrick; Desroches, Sophie; Lichtenstein, Alice H; Lamarche, Benoît

    2013-01-01

    We investigated the effect of weight loss, independent of change in diet composition, on HDL and apoAI metabolism in men with metabolic syndrome (MetS). Subjects (19 men with MetS [NCEP-ATPIII]) were fed an isoenergetic Mediterranean-style diet for 5 weeks (all foods provided). Participants then underwent a 20-week free-living period during which they were counseled to restrict energy intake, after which they were again fed an isoenergetic Mediterranean-style diet for 5 weeks. At the end of the two controlled diets, participants received a single bolus of [5,5,5-(2)H(3)] (L)-leucine, and fasting blood samples were collected over a 96 h period. ApoAI kinetic was assessed using multicompartmental modeling of the tracer enrichment data. Participants achieved a 9.1 ± 2.8% reduction in body weight (P < 0.001). Weight loss resulted in an increase in plasma HDL-cholesterol (HDL-C) concentrations of 6.0% (P = 0.059) and HDL(3)-C of 7.9% (P = 0.045), attributable to a reduction in apoAI fractional catabolic rate (-7.8%; P = 0.046) with no change in apoAI production rate (2.2%; P = 0.58). These data indicate that weight loss, independent of variation in diet composition, increases plasma HDL primarily by delaying the catabolism of apoAI.

  13. A novel mutation of the apolipoprotein A-I gene in a family with familial combined hyperlipidemia.

    PubMed

    Pisciotta, Livia; Fasano, Tommaso; Calabresi, Laura; Bellocchio, Antonella; Fresa, Raffaele; Borrini, Claudia; Calandra, Sebastiano; Bertolini, Stefano

    2008-05-01

    We report a large family in which four members showed a plasma lipid profile consistent with the clinical diagnosis of familial combined hyperlipidemia (FCHL). One of these patients was found to have markedly reduced HDL cholesterol (HDL-C) (0.72 mmol/l) and Apo A-I (72 mg/dl) levels, a condition suggestive of the presence of a mutation in one of the HDL-related genes. The analysis of APOA1 gene revealed that this patient was heterozygous for a cytosine insertion in exon 3 (c.49-50 ins C), resulting in a frame-shift and premature stop codon at position 26 of pro-Apo A-I (Q17PFsX10). This novel mutation, which prevents the synthesis of Apo A-I, was also found in four family members, including three siblings and the daughter of the proband. Carriers of Apo A-I mutation had significantly lower HDL-C and Apo A-I than non-carriers family members (0.77+/-0.15 mmol/l vs. 1.15+/-0.20 mmol/l, P<0.005; 71.4+/-9.1mg/dl vs. 134.0+/-14.7 mg/dl, P<0.005, respectively). Two of the APOA1 mutation carriers, who were also heavy smokers, had fibrous plaques in the carotid arteries causing mild stenosis (20%). The intimal-media thickness in the two other adult carriers was within the normal range. The other non-carriers family members with FCHL had either overt vascular disease or carotid atherosclerosis at ultrasound examination. This observation suggests that the low HDL-C/low Apo A-I phenotype may result from a genetic defect directly affecting HDL metabolism, even in the context of a dyslipidemia which, like FCHL, is associated with low plasma HDL-C. PMID:17950741

  14. BREFELDIN A INHIBITS CHOLESTEROL EFFLUX WITHOUT AFFECTING THE RATE OF CELLULAR UPTAKE AND RESECRETION OF APOLIPOPROTEIN A-I IN ADIPOCYTES

    PubMed Central

    Verghese, Philip B; Arrese, Estela L; Howard, Alisha D; Soulages, Jose L

    2008-01-01

    A possible role of cellular uptake and re-secretion of apoA-I in the mechanism of cholesterol efflux induced by apoA-I was investigated using a novel experimental approach. Incubation of adipocytes with a recombinant human apoA-I containing a consensus PKA phosphorylation site, pka-ApoA-I, leads to the appearance of phosphorylated protein in the cell culture medium unambiguously proving cellular uptake and re-secretion of pka-ApoA-I. Phosphorylation of apoA-I is abolished by PKA inhibitors and enhanced by PKA activators demonstrating the specific involvement of PKA. Studies on the concentration dependence of pka-apoA-I phosphorylation and competition experiments with human apoA-I suggest that apolipoprotein uptake is a receptor mediated process. A possible role of apoA-I recycling in the mechanism of cholesterol efflux was investigated by determining the rates of apoA-I induced cholesterol efflux and apoA-I recycling in the presence and in the absence of Brefeldin A (BFA). The studies showed that BFA strongly inhibits cholesterol efflux without affecting the rate of apoA-I recycling. Since BFA affects vesicular trafficking of ABCA1, this study suggests that the interaction of apoA-I with ABCA1 does not mediate apolipoprotein uptake and re-secretion. This result suggests that lipidation of apoA-I and apolipoprotein uptake/re-secretion are independent processes. PMID:18708026

  15. Apolipoprotein E promotes lipid accumulation and differentiation in human adipocytes

    SciTech Connect

    Lasrich, Dorothee; Bartelt, Alexander; Grewal, Thomas; Heeren, Joerg

    2015-09-10

    Several studies in mice indicate a role for apolipoprotein E (APOE) in lipid accumulation and adipogenic differentiation in adipose tissue. However, little is yet known if APOE functions in a similar manner in human adipocytes. This prompted us to compare lipid loading and expression of adipocyte differentiation markers in APOE-deficient and control adipocytes using the differentiated human mesenchymal stem cell line hMSC-Tert as well as primary human and mouse adipocytes as model systems. Differentiated hMSC-Tert were stably transduced with or without siRNA targeting APOE while murine adipocytes were isolated from wild type and Apoe knockout mice. Human APOE knockdown hMSC-Tert adipocytes accumulated markedly less triglycerides compared to control cells. This correlated with strongly decreased gene expression levels of adipocyte markers such as adiponectin (ADIPOQ) and fatty acid binding protein 4 (FABP4) as well as the key transcription factor driving adipocyte differentiation, peroxisome proliferator activator receptor gamma (PPARG), in particular the PPARG2 isoform. Similarly, differentiation of murine Apoe-deficient adipocytes was characterized by reduced gene expression of Adipoq, Fabp4 and Pparg. Interestingly, incubation of APOE-deficient hMSC-Tert adipocytes with conditioned media from APOE3-overexpressing adipocytes or APOE-containing Very Low Density Lipoprotein (VLDL) partially restored triglyceride accumulation, but were unable to induce adipocyte differentiation, as judged by expression of adipocyte markers. Taken together, depletion of endogenous APOE in human adipocytes severely impairs lipid accumulation, which is associated with an inability to initiate differentiation. - Highlights: • Immortalized human mesenchymal stem cells were used to study adipocyte development. • Knockdown of endogenous APOE lead to impaired lipid accumulation and adipogenesis. • APOE supplementation partially restored lipid accumulation but not differentiation.

  16. Distinct Hepatic Receptors for Low Density Lipoprotein and Apolipoprotein E in Humans

    NASA Astrophysics Data System (ADS)

    Hoeg, Jeffrey M.; Demosky, Stephen J.; Gregg, Richard E.; Schaefer, Ernst J.; Brewer, H. Bryan

    1985-02-01

    Since the liver is a central organ for lipid and lipoprotein synthesis and catabolism, hepatic receptors for specific apolipoproteins on plasma lipoproteins would be expected to modulate lipid and lipoprotein metabolism. The role of hepatic receptors for low density lipoproteins and apolipoprotein E-containing lipoproteins was evaluated in patients with complementary disorders in lipoprotein metabolism: abetalipoproteinemia and homozygous familial hypercholesterolemia. In addition, hepatic membranes from a patient with familial hypercholesterolemia were studied and compared before and after portacaval shunt surgery. The results establish that the human liver has receptors for apolipoproteins B and E. Furthermore, in the human, hepatic receptors for low density lipoproteins and apolipoprotein E are genetically distinct and can undergo independent control.

  17. Overexpression of apolipoprotein A-I fused to an anti-transforming growth factor beta peptide modulates the tumorigenicity and immunogenicity of mouse colon cancer cells.

    PubMed

    Medina-Echeverz, José; Vasquez, Marcos; Gomar, Celia; Ardaiz, Nuria; Berraondo, Pedro

    2015-06-01

    Transforming growth factor beta (TGF-β) promotes tumor growth, invasion and metastasis in established tumors. In this study, we analyzed the effect of overexpressing an anti-TGF-β peptide fused to apolipoprotein A-I (ApoA-I) as a scaffold molecule. We generated and characterized stable MC38 colon carcinoma clones expressing ApoA-I fused to the anti-TGF-β peptide P144 and ApoA-I as control cells. We evaluated in vitro the gene expression profile, cell cycle and anchorage-independent growth. The in vivo tumorigenic potential and immunogenicity were analyzed inoculating the MC38 clones into C57BL/6 mice, recombination-activating gene 1 knockout mice or mice deficient in NK cells either subcutaneously or intrasplenically to generate hepatic metastases. While overexpression of ApoA-I had no effect on the parameters analyzed, ApoA-I fused to P144 markedly diminished the tumorigenic capacity and metastatic potential of MC38 in vitro and in vivo, thus generating a highly immunogenic cell line. MC38 cells transfected with ApoA-I fused to P144 triggered memory T cell responses able to eliminate the parental cell line upon re-challenge. In summary, expression of ApoA-I fused to P144 is a novel strategy to modulate TGF-β in tumor cells. These results highlight the potential of TGF-β as a target in the development of new antitumor treatments.

  18. An Evaluation of the Crystal Structure of C-terminal Truncated Apolipoprotein A-I in Solution Reveals Structural Dynamics Related to Lipid Binding.

    PubMed

    Melchior, John T; Walker, Ryan G; Morris, Jamie; Jones, Martin K; Segrest, Jere P; Lima, Diogo B; Carvalho, Paulo C; Gozzo, Fábio C; Castleberry, Mark; Thompson, Thomas B; Davidson, W Sean

    2016-03-01

    Apolipoprotein (apo) A-I mediates many of the anti-atherogenic functions attributed to high density lipoprotein. Unfortunately, efforts toward a high resolution structure of full-length apoA-I have not been fruitful, although there have been successes with deletion mutants. Recently, a C-terminal truncation (apoA-I(Δ185-243)) was crystallized as a dimer. The structure showed two helical bundles connected by a long, curved pair of swapped helical domains. To compare this structure to that existing under solution conditions, we applied small angle x-ray scattering and isotope-assisted chemical cross-linking to apoA-I(Δ185-243) in its dimeric and monomeric forms. For the dimer, we found evidence for the shared domains and aspects of the N-terminal bundles, but not the molecular curvature seen in the crystal. We also found that the N-terminal bundles equilibrate between open and closed states. Interestingly, this movement is one of the transitions proposed during lipid binding. The monomer was consistent with a model in which the long shared helix doubles back onto the helical bundle. Combined with the crystal structure, these data offer an important starting point to understand the molecular details of high density lipoprotein biogenesis.

  19. An abundant dysfunctional apolipoprotein A1 in human atheroma

    PubMed Central

    Huang, Ying; DiDonato, Joseph A.; Levison, Bruce S.; Schmitt, Dave; Li, Lin; Wu, Yuping; Buffa, Jennifer; Kim, Timothy; Gerstenecker, Gary; Gu, Xiaodong; Kadiyala, Chandra; Wang, Zeneng; Culley, Miranda K.; Hazen, Jennie E.; DiDonato, Anthony J.; Fu, Xiaoming; Berisha, Stela; Peng, Daoquan; Nguyen, Truc; Liang, Shaohong; Chuang, Chia-Chi; Cho, Leslie; Plow, Edward F.; Fox, Paul L.; Gogonea, Valentin; Tang, W.H. Wilson; Parks, John S.; Fisher, Edward A.; Smith, Jonathan D.; Hazen, Stanley L.

    2014-01-01

    Recent studies indicate high density lipoproteins (HDL) and their major structural protein, apolipoprotein A1 (apoA1), recovered from human atheroma, are dysfunctional and extensively oxidized by myeloperoxidase (MPO), while in vitro oxidation of apoA1/HDL by MPO impairs its cholesterol acceptor function. We developed a high affinity monoclonal antibody (mAb) that specifically recognizes apoA1/HDL modified by the MPO/H2O2/Cl-system using phage display affinity maturation. An oxindolyl alanine (2-OH-Trp) moiety at tryptophan 72 of apoA1 is the immunogenic epitope. Mutagenesis studies confirm a critical role for apoA1 Trp72 in MPO-mediated inhibition of ABCA1-dependent cholesterol acceptor activity of apoA1 in vitro and in vivo. ApoA1 containing a 2-OH-Trp72 group (oxTrp72-apoA1) is in low abundance within the circulation, but accounts for 20% of the apoA1 in atherosclerotic plaque. OxTrp72-apoA1 recovered from human atheroma or plasma was lipid-poor, virtually devoid of cholesterol acceptor activity, and demonstrated both potent pro-inflammatory activities on endothelial cells and impaired HDL biogenesis activity in vivo. Elevated oxTrp72-apoA1 levels in subjects presenting to a cardiology clinic (n=627) were associated with increased cardiovascular disease risk. Circulating oxTrp72-apoA1 levels may serve as a way to monitor a pro-atherogenic process in the artery wall. PMID:24464187

  20. Modified apolipoprotein (apo) A-I by artificial sweetener causes severe premature cellular senescence and atherosclerosis with impairment of functional and structural properties of apoA-I in lipid-free and lipid-bound state.

    PubMed

    Jang, Wookju; Jeoung, Nam Ho; Cho, Kyung-Hyun

    2011-05-01

    Long-term consumption of artificial sweeteners (AS) has been the recent focus of safety concerns. However, the potential risk of the AS in cardiovascular disease and lipoprotein metabolism has not been investigated sufficiently. We compared the influence of AS (aspartame, acesulfame K, and saccharin) and fructose in terms of functional and structural correlations of apolipoprotein (apo) A-I and high-density lipoproteins (HDL), which have atheroprotective effects. Long-term treatment of apoA-I with the sweetener at physiological concentration (3 mM for 168 h) resulted in loss of antioxidant and phospholipid binding activities with modification of secondary structure. The AS treated apoA-I exhibited proteolytic cleavage to produce 26 kDa-fragment. They showed pro-atherogenic properties in acetylated LDL phagocytosis of macrophages. Each sweetener alone or sweetener-treated apoA-I caused accelerated senescence in human dermal fibroblasts. These results suggest that long-term consumption of AS might accelerate atherosclerosis and senescence via impairment of function and structure of apoA-I and HDL.

  1. Levels and changes of HDL cholesterol and apolipoprotein A-I in relation to risk of cardiovascular events among statin-treated patients; a meta-analysis

    PubMed Central

    Boekholdt, S. Matthijs; Arsenault, Benoit J.; Hovingh, G. Kees; Mora, Samia; Pedersen, Terje R.; LaRosa, John C.; Welch, K.M.A.; Amarenco, Pierre; DeMicco, David A.; Tonkin, Andrew M.; Sullivan, David R.; Kirby, Adrienne; Colhoun, Helen M.; Hitman, Graham A.; Betteridge, D. John; Durrington, Paul N.; Clearfield, Michael B.; Downs, John R.; Gotto, Antonio M.; Ridker, Paul M.; Kastelein, John J.P.

    2013-01-01

    Background It is unclear whether levels of high-density lipoprotein cholesterol (HDL-C) or apolipoprotein A-I (apoA-I) remain inversely associated with cardiovascular risk among patients who achieve very low levels of low-density lipoprotein cholesterol (LDL-C) on statin therapy. It is also unknown whether a rise in HDL-C or apoA-I after initiation of statin therapy is associated with a reduced cardiovascular risk. Methods and results We performed a meta-analysis of 8 statin trials in which lipids and apolipoproteins were determined in all study participants at baseline and at 1-year follow-up. Individual patient data were obtained for 38,153 trial participants allocated to statin therapy, of whom 5387 suffered a major cardiovascular event. HDL-C levels were associated with a reduced risk of major cardiovascular events (adjusted hazard ratio 0.83, 95%CI 0.81–0.86 per 1 standard deviation increment), as were apoA-I levels (HR 0.79, 95%CI 0.72–0.82). This association was also observed among patients achieving on-statin LDL-C levels < 50 mg/dL. An increase of HDL-C was not associated with reduced cardiovascular risk (HR 0.98, 95%CI 0.94–1.01 per 1 standard deviation increment), whereas a rise in apoA-I was (HR 0.93, 95%CI 0.90–0.97). Conclusions Among patients treated with statin therapy, HDL-C and apoA-I levels were strongly associated with a reduced cardiovascular risk, even among those achieving very low LDL-C. An apoA-I increase was associated with a reduced risk of major cardiovascular events, whereas for HDL-C this was not the case. These findings suggest that therapies that increase apoA-I concentration require further exploration with regard to cardiovascular risk reduction. PMID:23965489

  2. The Effect of Preoperative Apolipoprotein A-I on the Prognosis of Surgical Renal Cell Carcinoma: A Retrospective Large Sample Study.

    PubMed

    Guo, Shengjie; He, Xiaobo; Chen, Qian; Yang, Guangwei; Yao, Kai; Dong, Pei; Ye, Yunlin; Chen, Dong; Zhang, Zhiling; Qin, Zike; Liu, Zhuowei; Li, Zaishang; Xue, Yunfei; Zhang, Meng; Liu, Ruiwu; Zhou, Fangjian; Han, Hui

    2016-03-01

    The prognostic value of serum lipid-profile in renal cell cancer (RCC) remains unknown. The purpose of the study is to explore the association between the serum lipid-profile and RCC patients.The levels of preoperative serum lipid-profile (including cholesterol, triglycerides, high-density lipoprotein-cholesterol [HDL-C], low-density lipoprotein-cholesterol [LDL-C], apolipoprotein A-I [ApoA-I], and apolipoprotein B [ApoB]) were retrospectively performed in 786 patients with RCC. The cutoff values of the lipids were determined by the receiver-operating characteristic (ROC) curve analysis. Univariate and multivariate Cox regression analyses were performed to investigate the prognostic value of serum lipids in RCC.Combined ROC analysis and univariate and multivariate Cox regression analyses, for overall survival (OS), revealed patients with low ApoA-I (<1.04) had significantly lower OS than the high ApoA-I (≥1.04) group (multivariate Cox regression analyses, hazard ratio [HR], 0.57; P = 0.003). Not only in the whole RCC cohort but also in the subgroups stratified according to the pT1-2 (P = 0.002), pN0 (P < 0.001), and pM0 (P = 0.001) status, respectively. Moreover, in the 755 patients with nonmetastasis, the low ApoA-I group was also associated with shortened disease-free survival (DFS) time compared to the high ApoA-I group (multivariate Cox regression analyses, HR, 0.65; P = 0.033). However, the other lipids were not independent prognostic factors for surgical RCC.An elevated level of preoperative ApoA-I was demonstrated to be related with better survival in patients with surgical RCC. Measuring the preoperative ApoA-I might be a simple way for finding the poor prognostic patients who should enrolled in further clinical trials and management.

  3. Apolipoprotein A-I Mimetic Peptide D-4F Reduces Cardiac Hypertrophy and Improves Apolipoprotein A-I-Mediated Reverse Cholesterol Transport From Cardiac Tissue in LDL Receptor-null Mice Fed a Western Diet.

    PubMed

    Han, Jie; Zhang, Song; Ye, Ping; Liu, Yong-Xue; Qin, Yan-Wen; Miao, Dong-Mei

    2016-05-01

    Epidemiological studies have suggested that hypercholesterolemia is an independent determinant of increased left ventricular (LV) mass. Because high-density lipoprotein and its major protein apolipoprotein A-I (apoA-I) mediate reverse cholesterol transport (RCT) and have cardiac protective effects, we hypothesized that the apoA-I mimetic peptide D-4F could promote RCT in cardiac tissue and decrease cardiac hypertrophy induced by hypercholesterolemia. Low-density lipoprotein receptor-null mice were fed by a Western diet for 18 weeks and then randomized to receive water, or D-4F 0.3 mg/mL, or D-4F 0.5 mg/mL added to drinking water for 6 weeks. After D-4F administration, an increase in high-density lipoprotein cholesterol and a decrease in low-density lipoprotein cholesterol, total cholesterol, and triglyceride in a trend toward dose-responsivity were found in cardiac tissue. Ultrasound biomicroscopy revealed a reduction in LV posterior wall end-diastolic dimension, and an increase in mitral valve E/A ratio and LV ejection fraction. Hematoxylin-eosin staining showed reduced LV wall thickness and myocardial cell diameter. The protein levels of ABCA1 and LXRα were elevated in cardiac tissue of D-4F treated mice compared with the controls (P < 0.05). These results demonstrated that D-4F treatment reduced cardiac hypertrophy, and improved cardiac performance in low-density lipoprotein receptor-null mice fed a Western diet, presumably through the LXRα-ABCA1 pathway associated with enhanced myocardial RCT.

  4. Stimulation of Hepatic Apolipoprotein A-I Production by Novel Thieno-Triazolodiazepines: Roles of the Classical Benzodiazepine Receptor, PAF Receptor, and Bromodomain Binding.

    PubMed

    Kempen, Herman J; Bellus, Daniel; Fedorov, Oleg; Nicklisch, Silke; Filippakopoulos, Panagis; Picaud, Sarah; Knapp, Stefan

    2013-01-01

    Expression and secretion of apolipoprotein A-I (apoA-I) by cultured liver cells can be markedly stimulated by triazolodiazepines (TZDs). It has been shown previously that the thieno-TZD Ro 11-1464 increases plasma levels of apoA-I and in vivomacrophage reverse cholesterol transport in mice. However, these effects were only seen at high doses, at which the compound could act on central benzodiazepine (BZD) receptors or platelet activating factor (PAF) receptors, interfering with its potential utility. In this work, we describe 2 new thieno-TZDs MDCO-3770 and MDCO-3783, both derived from Ro 11-1464. These compounds display the same high efficacy on apoA-I production, metabolic stability, and lack of cytotoxicity in cultured hepatocytes as Ro 11-1464, but they do not bind to the central BZD receptor and PAF receptor. The quinazoline RVX-208 was less efficacious in stimulating apoA-I production and displayed signs of cytotoxicity. Certain TZDs stimulating apoA-I production are now known to be inhibitors of bromodomain (BRD) extra-terminal (BET) proteins BRDT, BRD2, BRD3, and BRD4, and this inhibition was inferred as a main molecular mechanism for their effect on apoA-I expression. We show here that the thieno-TZD (+)-JQ1, a potent BET inhibitor, strongly stimulated apoA-I production in Hep-G2 cells, but that its enantiomer (-)-JQ1, which has no BET inhibitor activity, also showed considerable effect on apoA-I production. MDCO-3770 and MDCO-3783 also inhibited BRD3 and BRD4 in vitro, with potency somewhat below that of (+)-JQ1. We conclude that the effect of thieno-TZDs on apoA-I expression is not due to inhibition of the BZD or PAF receptors and is not completely explained by transcriptional repression by BET proteins. PMID:25278768

  5. Stimulation of Hepatic Apolipoprotein A-I Production by Novel Thieno-Triazolodiazepines: Roles of the Classical Benzodiazepine Receptor, PAF Receptor, and Bromodomain Binding

    PubMed Central

    Kempen, Herman J; Bellus, Daniel; Fedorov, Oleg; Nicklisch, Silke; Filippakopoulos, Panagis; Picaud, Sarah; Knapp, Stefan

    2013-01-01

    Expression and secretion of apolipoprotein A-I (apoA-I) by cultured liver cells can be markedly stimulated by triazolodiazepines (TZDs). It has been shown previously that the thieno-TZD Ro 11-1464 increases plasma levels of apoA-I and in vivomacrophage reverse cholesterol transport in mice. However, these effects were only seen at high doses, at which the compound could act on central benzodiazepine (BZD) receptors or platelet activating factor (PAF) receptors, interfering with its potential utility. In this work, we describe 2 new thieno-TZDs MDCO-3770 and MDCO-3783, both derived from Ro 11-1464. These compounds display the same high efficacy on apoA-I production, metabolic stability, and lack of cytotoxicity in cultured hepatocytes as Ro 11-1464, but they do not bind to the central BZD receptor and PAF receptor. The quinazoline RVX-208 was less efficacious in stimulating apoA-I production and displayed signs of cytotoxicity. Certain TZDs stimulating apoA-I production are now known to be inhibitors of bromodomain (BRD) extra-terminal (BET) proteins BRDT, BRD2, BRD3, and BRD4, and this inhibition was inferred as a main molecular mechanism for their effect on apoA-I expression. We show here that the thieno-TZD (+)-JQ1, a potent BET inhibitor, strongly stimulated apoA-I production in Hep-G2 cells, but that its enantiomer (−)-JQ1, which has no BET inhibitor activity, also showed considerable effect on apoA-I production. MDCO-3770 and MDCO-3783 also inhibited BRD3 and BRD4 in vitro, with potency somewhat below that of (+)-JQ1. We conclude that the effect of thieno-TZDs on apoA-I expression is not due to inhibition of the BZD or PAF receptors and is not completely explained by transcriptional repression by BET proteins. PMID:25278768

  6. Kinetic and thermodynamic analyses of spontaneous exchange between high-density lipoprotein-bound and lipid-free apolipoprotein A-I.

    PubMed

    Handa, Daisuke; Kimura, Hitoshi; Oka, Tatsuya; Takechi, Yuki; Okuhira, Keiichiro; Phillips, Michael C; Saito, Hiroyuki

    2015-02-01

    It is thought that apolipoprotein A-I (apoA-I) spontaneously exchanges between high-density lipoprotein (HDL)-bound and lipid-free states, which is relevant to the occurrence of preβ-HDL particles in plasma. To improve our understanding of the mechanistic basis for this phenomenon, we performed kinetic and thermodynamic analyses for apoA-I exchange between discoidal HDL-bound and lipid-free forms using fluorescence-labeled apoA-I variants. Gel filtration experiments demonstrated that addition of excess lipid-free apoA-I to discoidal HDL particles promotes exchange of apoA-I between HDL-associated and lipid-free pools without alteration of the steady-state HDL particle size. Kinetic analysis of time-dependent changes in NBD fluorescence upon the transition of NBD-labeled apoA-I from HDL-bound to lipid-free state indicates that the exchange kinetics are independent of the collision frequency between HDL-bound and lipid-free apoA-I, in which the lipid binding ability of apoA-I affects the rate of association of lipid-free apoA-I with the HDL particles and not the rate of dissociation of HDL-bound apoA-I. Thus, C-terminal truncations or mutations that reduce the lipid binding affinity of apoA-I strongly impair the transition of lipid-free apoA-I to the HDL-bound state. Thermodynamic analysis of the exchange kinetics demonstrated that the apoA-I exchange process is enthalpically unfavorable but entropically favorable. These results explain the thermodynamic basis of the spontaneous exchange reaction of apoA-I associated with HDL particles. The altered exchangeability of dysfunctional apoA-I would affect HDL particle rearrangement, leading to perturbed HDL metabolism.

  7. Contribution of apolipoprotein A-I to the reduction in high-sensitivity C-reactive protein levels by different statins: comparative study of pitavastatin and atorvastatin.

    PubMed

    Tani, Shigemasa; Takahashi, Atsuhiko; Nagao, Ken; Hirayama, Atsushi

    2015-11-01

    Recently, investigation may have focused on modification of apolipoprotein A-I (apoA-I) associated with anti-inflammatory effect for the potential prevention of cardiovascular events. The purpose of this study was to evaluate the effects of atorvastatin and pitavastatin on serum apoA-I levels and to investigate the role of apoA-I in the anti-inflammatory effect of statin. We conducted a 6-month, prospective, randomized, open-label study in which we assigned hypercholesterolemic patients to a pitavastatin group (n = 52; 2 mg/day) or an atorvastatin group (n = 52; 10 mg/day) to investigate the effects of these two statins on the serum apoA-I levels and serum high-sensitivity C-reactive protein (hs-CRP) levels. There were no significant differences between the two groups in the changes in the low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), or hs-CRP levels, but the change in apoA-I in the pitavastatin group was significantly greater than in the atorvastatin group (5.3 vs. 1.4 %; p = 0.0001). A stepwise regression analysis revealed that the percent change in (Δ) serum apoA-I level was an independent predictor of the Δ serum hs-CRP (standard correlation coefficient = -0.198; p = 0.047). However, there was a significant negative correlation between the Δ apoA-I levels and Δ hs-CRP levels in the pitavastatin group (r = -0.283, p = 0.042), but not the atorvastatin group (r = -0.133, p = 0.356). The results suggest that the contribution of apoA-I to the reduction in serum hs-CRP levels by these two statins may be different. A decrease in hs-CRP level accompanied by an increase in apoA-I level may be involved in the pleiotropic effects of pitavastatin.

  8. ITRAQ-based quantitative proteomics reveals apolipoprotein A-I and transferrin as potential serum markers in CA19-9 negative pancreatic ductal adenocarcinoma.

    PubMed

    Lin, Chao; Wu, Wen-Chuan; Zhao, Guo-Chao; Wang, Dan-Song; Lou, Wen-Hui; Jin, Da-Yong

    2016-08-01

    Currently the diagnosis of pancreatic ductal adenocarcinoma (PDAC) relies on CA19-9 and radiological means, whereas some patients do not have elevated levels of CA19-9 secondary to pancreatic cancer. The purpose of this study was to identify potential serum biomarkers for CA19-9 negative PDAC.A total of 114 serum samples were collected from 3 groups: CA19-9 negative PDAC patients (n = 34), CA19-9 positive PDAC patients (n = 44), and healthy volunteers (n = 36), whereas the first 12 samples from each group were used for isobaric tags for relative and absolute quantitation (iTRAQ) analysis. Thereafter, candidate biomarkers were selected for validation by enzyme-linked immunosorbent assay (ELISA) with the rest specimens.Using the iTRAQ approach, a total of 5 proteins were identified as significantly different between CA19-9 negative PDAC patients and healthy subjects according to our defined criteria. Apolipoprotein A-I (APOA-I) and transferrin (TF) were selected to validate the proteomic results by ELISA in a further 78 serum specimens. It revealed that TF significantly correlated with the degree of histological differentiation (P = 0.042), and univariate and multivariate analyses indicated that TF is an independent prognostic factor for survival (hazard ratio, 0.302; 95% confidence interval, 0.118-0.774; P = 0.013) of patients with PDAC after curative surgery.ITRAQ-based quantitative proteomics revealed that APOA-I and TF may be potential CA19-9 negative PDAC serum markers.

  9. Hepatocyte-specific Dyrk1a gene transfer rescues plasma apolipoprotein A-I levels and aortic Akt/GSK3 pathways in hyperhomocysteinemic mice.

    PubMed

    Tlili, Asma; Jacobs, Frank; de Koning, Leanne; Mohamed, Sirine; Bui, Linh-Chi; Dairou, Julien; Belin, Nicole; Ducros, Véronique; Dubois, Thierry; Paul, Jean-Louis; Delabar, Jean-Maurice; De Geest, Bart; Janel, Nathalie

    2013-06-01

    Hyperhomocysteinemia, characterized by high plasma homocysteine levels, is recognized as an independent risk factor for cardiovascular diseases. The increased synthesis of homocysteine, a product of methionine metabolism involving B vitamins, and its slower intracellular utilization cause increased flux into the blood. Plasma homocysteine level is an important reflection of hepatic methionine metabolism and the rate of processes modified by B vitamins as well as different enzyme activity. Lowering homocysteine might offer therapeutic benefits. However, approximately 50% of hyperhomocysteinemic patients due to cystathionine-beta-synthase deficiency are biochemically responsive to pharmacological doses of B vitamins. Therefore, effective treatments to reduce homocysteine levels are needed, and gene therapy could provide a novel approach. We recently showed that hepatic expression of DYRK1A, a serine/threonine kinase, is negatively correlated with plasma homocysteine levels in cystathionine-beta-synthase deficient mice, a mouse model of hyperhomocysteinemia. Therefore, Dyrk1a is a good candidate for gene therapy to normalize homocysteine levels. We then used an adenoviral construct designed to restrict expression of DYRK1A to hepatocytes, and found decreased plasma homocysteine levels after hepatocyte-specific Dyrk1a gene transfer in hyperhomocysteinemic mice. The elevation of pyridoxal phosphate was consistent with the increase in cystathionine-beta-synthase activity. Commensurate with the decreased plasma homocysteine levels, targeted hepatic expression of DYRK1A resulted in elevated plasma paraoxonase-1 activity and apolipoprotein A-I levels, and rescued the Akt/GSK3 signaling pathways in aorta of mice, which can prevent homocysteine-induced endothelial dysfunction. These results demonstrate that hepatocyte-restricted Dyrk1a gene transfer can offer a useful therapeutic targets for the development of new selective homocysteine lowering therapy. PMID:23429073

  10. ITRAQ-based quantitative proteomics reveals apolipoprotein A-I and transferrin as potential serum markers in CA19-9 negative pancreatic ductal adenocarcinoma

    PubMed Central

    Lin, Chao; Wu, Wen-Chuan; Zhao, Guo-Chao; Wang, Dan-Song; Lou, Wen-Hui; Jin, Da-Yong

    2016-01-01

    Abstract Currently the diagnosis of pancreatic ductal adenocarcinoma (PDAC) relies on CA19-9 and radiological means, whereas some patients do not have elevated levels of CA19-9 secondary to pancreatic cancer. The purpose of this study was to identify potential serum biomarkers for CA19-9 negative PDAC. A total of 114 serum samples were collected from 3 groups: CA19-9 negative PDAC patients (n = 34), CA19-9 positive PDAC patients (n = 44), and healthy volunteers (n = 36), whereas the first 12 samples from each group were used for isobaric tags for relative and absolute quantitation (iTRAQ) analysis. Thereafter, candidate biomarkers were selected for validation by enzyme-linked immunosorbent assay (ELISA) with the rest specimens. Using the iTRAQ approach, a total of 5 proteins were identified as significantly different between CA19-9 negative PDAC patients and healthy subjects according to our defined criteria. Apolipoprotein A-I (APOA-I) and transferrin (TF) were selected to validate the proteomic results by ELISA in a further 78 serum specimens. It revealed that TF significantly correlated with the degree of histological differentiation (P = 0.042), and univariate and multivariate analyses indicated that TF is an independent prognostic factor for survival (hazard ratio, 0.302; 95% confidence interval, 0.118–0.774; P = 0.013) of patients with PDAC after curative surgery. ITRAQ-based quantitative proteomics revealed that APOA-I and TF may be potential CA19-9 negative PDAC serum markers. PMID:27495108

  11. An experimentally robust model of monomeric apolipoprotein A-I created from a chimera of two X-ray structures and molecular dynamics simulations.

    PubMed

    Segrest, Jere P; Jones, Martin K; Shao, Baohai; Heinecke, Jay W

    2014-12-01

    High-density lipoprotein (HDL) retards atherosclerosis by accepting cholesterol from the artery wall. However, the structure of the proposed acceptor, monomeric apolipoprotein A-I (apoA-I), the major protein of HDL, is poorly understood. Two published models for monomeric apoA-I used cross-linking distance constraints to derive best fit conformations. This approach has limitations. (i) Cross-linked peptides provide no information about secondary structure. (ii) A protein chain can be folded in multiple ways to create a best fit. (iii) Ad hoc folding of a secondary structure is unlikely to produce a stable orientation of hydrophobic and hydrophilic residues. To address these limitations, we used a different approach. We first noted that the dimeric apoA-I crystal structure, (Δ185-243)apoA-I, is topologically identical to a monomer in which helix 5 forms a helical hairpin, a monomer with a hydrophobic cleft running the length of the molecule. We then realized that a second crystal structure, (Δ1-43)apoA-I, contains a C-terminal structure that fits snuggly via aromatic and hydrophobic interactions into the hydrophobic cleft. Consequently, we combined these crystal structures into an initial model that was subjected to molecular dynamics simulations. We tested the initial and simulated models and the two previously published models in three ways: against two published data sets (domains predicted to be helical by H/D exchange and six spin-coupled residues) and against our own experimentally determined cross-linking distance constraints. We note that the best fit simulation model, superior by all tests to previously published models, has dynamic features of a molten globule with interesting implications for the functions of apoA-I. PMID:25423138

  12. Apolipoprotein AI tertiary structures determine stability and phospholipid-binding activity of discoidal high-density lipoprotein particles of different sizes

    SciTech Connect

    Chen, Bin; Ren, Xuefeng; Neville, Tracey; Jerome, W. Gray; Hoyt, David W.; Sparks, Daniel L.; Ren, Gang; Wang, Jianjun

    2009-05-18

    Human high-density lipoprotein (HDL) plays a key role in the reverse cholesterol transport pathway that delivers excess cholesterol back to the liver for clearance. In vivo, HDL particles vary in size, shape and biological function. The discoidal HDL is a 140-240 kDa, disk-shaped intermediate of mature HDL. During mature spherical HDL formation, discoidal HDLs play a key role in loading cholesterol ester onto the HDL particles by activating the enzyme, lecithin:cholesterol acyltransferase (LCAT). One of the major problems for high-resolution structural studies of discoidal HDL is the difficulty in obtaining pure and, foremost, homogenous sample. We demonstrate here that the commonly used cholate dialysis method for discoidal HDL preparation usually contains 5-10% lipid-poor apoAI that significantly interferes with the high-resolution structural analysis of discoidal HDL using biophysical methods. Using an ultracentrifugation method, we quickly removed lipid-poor apoAI. We also purified discoidal reconstituted HDL (rHDL) into two pure discoidal HDL species of different sizes that are amendable for high-resolution structural studies. A small rHDL has a diameter of 7.6 nm, and a large rHDL has a diameter of 9.8 nm. We show that these two different sizes of discoidal HDL particles display different stability and phospholipid-binding activity. Interestingly, these property/functional differences are independent from the apoAI -helical secondary structure, but are determined by the tertiary structural difference of apoAI on different discoidal rHDL particles, as evidenced by two-dimensional NMR and negative stain electron microscopy data. Our result further provides the first high-resolution NMR data, demonstrating a promise of structural determination of discoidal HDL at atomic resolution using a combination of NMR and other biophysical techniques.

  13. Bile acid-activated nuclear receptor FXR suppresses apolipoprotein A-I transcription via a negative FXR response element

    PubMed Central

    Claudel, Thierry; Sturm, Ekkehard; Duez, Hélène; Torra, Inés Pineda; Sirvent, Audrey; Kosykh, Vladimir; Fruchart, Jean-Charles; Dallongeville, Jean; Hum, Dean W.; Kuipers, Folkert; Staels, Bart

    2002-01-01

    Serum levels of HDL are inversely correlated with the risk of coronary heart disease. The anti-atherogenic effect of HDL is partially mediated by its major protein constituent apoA-I. In this study, we identify bile acids that are activators of the nuclear receptor farnesoid X receptor (FXR) as negative regulators of human apoA-I expression. Intrahepatocellular accumulation of bile acids, as seen in patients with progressive familial intrahepatic cholestasis and biliary atresia, was associated with diminished apoA-I serum levels. In human apoA-I transgenic mice, treatment with the FXR agonist taurocholic acid strongly decreased serum concentrations and liver mRNA levels of human apoA-I, which was associated with reduced serum HDL levels. Incubation of human primary hepatocytes and hepatoblastoma HepG2 cells with bile acids resulted in a dose-dependent downregulation of apoA-I expression. Promoter mutation analysis and gel-shift experiments in HepG2 cells demonstrated that bile acid–activated FXR decreases human apoA-I promoter activity by a negative FXR response element mapped to the C site. FXR bound this site and repressed transcription in a manner independent of retinoid X receptor. The nonsteroidal synthetic FXR agonist GW4064 likewise decreased apoA-I mRNA levels and promoter activity in HepG2 cells. PMID:11927623

  14. A novel truncated form of apolipoprotein A-I transported by dense LDL is increased in diabetic patients1[S

    PubMed Central

    Cubedo, Judit; Padró, Teresa; García-Arguinzonis, Maisa; Vilahur, Gemma; Miñambres, Inka; Pou, Jose María; Ybarra, Juan; Badimon, Lina

    2015-01-01

    Diabetic (DM) patients have exacerbated atherosclerosis and high CVD burden. Changes in lipid metabolism, lipoprotein structure, and dysfunctional HDL are characteristics of diabetes. Our aim was to investigate whether serum ApoA-I, the main protein in HDL, was biochemically modified in DM patients. By using proteomic technologies, we have identified a 26 kDa ApoA-I form in serum. MS analysis revealed this 26 kDa form as a novel truncated variant lacking amino acids 1-38, ApoA-IΔ(1-38). DM patients show a 2-fold increase in ApoA-IΔ(1-38) over nondiabetic individuals. ApoA-IΔ(1-38) is found in LDL, but not in VLDL or HDL, with an increase in LDL3 and LDL4 subfractions. To identify candidate mechanisms of ApoA-I truncation, we investigated potentially involved enzymes by in silico data mining, and tested the most probable molecule in an established animal model of diabetes. We have found increased hepatic cathepsin D activity as one of the potential proteases involved in ApoA-I truncation. Cathepsin D-cleaved ApoA-I exhibited increased LDL binding affinity and decreased antioxidant activity against LDL oxidation. In conclusion, we show for the first time: a) presence of a novel truncated ApoA-I form, ApoA-IΔ(1-38), in human serum; b) ApoA-IΔ(1-38) is transported by LDL; c) ApoA-IΔ(1-38) is increased in dense LDL fractions of DM patients; and d) cathepsin D-ApoA-I truncation may lead to ApoA-IΔ(1-38) binding to LDLs, increasing their susceptibility to oxidation and contributing to the high cardiovascular risk of DM patients. PMID:26168996

  15. A novel truncated form of apolipoprotein A-I transported by dense LDL is increased in diabetic patients.

    PubMed

    Cubedo, Judit; Padró, Teresa; García-Arguinzonis, Maisa; Vilahur, Gemma; Miñambres, Inka; Pou, Jose María; Ybarra, Juan; Badimon, Lina

    2015-09-01

    Diabetic (DM) patients have exacerbated atherosclerosis and high CVD burden. Changes in lipid metabolism, lipoprotein structure, and dysfunctional HDL are characteristics of diabetes. Our aim was to investigate whether serum ApoA-I, the main protein in HDL, was biochemically modified in DM patients. By using proteomic technologies, we have identified a 26 kDa ApoA-I form in serum. MS analysis revealed this 26 kDa form as a novel truncated variant lacking amino acids 1-38, ApoA-IΔ(1-38). DM patients show a 2-fold increase in ApoA-IΔ(1-38) over nondiabetic individuals. ApoA-IΔ(1-38) is found in LDL, but not in VLDL or HDL, with an increase in LDL3 and LDL4 subfractions. To identify candidate mechanisms of ApoA-I truncation, we investigated potentially involved enzymes by in silico data mining, and tested the most probable molecule in an established animal model of diabetes. We have found increased hepatic cathepsin D activity as one of the potential proteases involved in ApoA-I truncation. Cathepsin D-cleaved ApoA-I exhibited increased LDL binding affinity and decreased antioxidant activity against LDL oxidation. In conclusion, we show for the first time: a) presence of a novel truncated ApoA-I form, ApoA-IΔ(1-38), in human serum; b) ApoA-IΔ(1-38) is transported by LDL; c) ApoA-IΔ(1-38) is increased in dense LDL fractions of DM patients; and d) cathepsin D-ApoA-I truncation may lead to ApoA-IΔ(1-38) binding to LDLs, increasing their susceptibility to oxidation and contributing to the high cardiovascular risk of DM patients.

  16. Quantification of serum apolipoproteins A-I and B-100 in clinical samples using an automated SISCAPA-MALDI-TOF-MS workflow.

    PubMed

    van den Broek, Irene; Nouta, Jan; Razavi, Morteza; Yip, Richard; Bladergroen, Marco R; Romijn, Fred P H T M; Smit, Nico P M; Drews, Oliver; Paape, Rainer; Suckau, Detlev; Deelder, André M; van der Burgt, Yuri E M; Pearson, Terry W; Anderson, N Leigh; Cobbaert, Christa M

    2015-06-15

    A fully automated workflow was developed and validated for simultaneous quantification of the cardiovascular disease risk markers apolipoproteins A-I (apoA-I) and B-100 (apoB-100) in clinical sera. By coupling of stable-isotope standards and capture by anti-peptide antibodies (SISCAPA) for enrichment of proteotypic peptides from serum digests to matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS detection, the standardized platform enabled rapid, liquid chromatography-free quantification at a relatively high throughput of 96 samples in 12h. The average imprecision in normo- and triglyceridemic serum pools was 3.8% for apoA-I and 4.2% for apoB-100 (4 replicates over 5 days). If stored properly, the MALDI target containing enriched apoA-1 and apoB-100 peptides could be re-analyzed without any effect on bias or imprecision for at least 7 days after initial analysis. Validation of the workflow revealed excellent linearity for daily calibration with external, serum-based calibrators (R(2) of 0.984 for apoA-I and 0.976 for apoB-100 as average over five days), and absence of matrix effects or interference from triglycerides, protein content, hemolysates, or bilirubins. Quantification of apoA-I in 93 normo- and hypertriglyceridemic clinical sera showed good agreement with immunoturbidimetric analysis (slope = 1.01, R(2) = 0.95, mean bias = 4.0%). Measurement of apoB-100 in the same clinical sera using both methods, however, revealed several outliers in SISCAPA-MALDI-TOF-MS measurements, possibly as a result of the lower MALDI-TOF-MS signal intensity (slope = 1.09, R(2) = 0.91, mean bias = 2.0%). The combination of analytical performance, rapid cycle time and automation potential validate the SISCAPA-MALDI-TOF-MS platform as a valuable approach for standardized and high-throughput quantification of apoA-I and apoB-100 in large sample cohorts.

  17. Apolipoprotein A-I in Labeo rohita: Cloning and functional characterisation reveal its broad spectrum antimicrobial property, and indicate significant role during ectoparasitic infection.

    PubMed

    Mohapatra, Amruta; Karan, Sweta; Kar, Banya; Garg, L C; Dixit, A; Sahoo, P K

    2016-08-01

    Apolipoprotein A-I (ApoA-I) is the most abundant and multifunctional high-density lipoprotein (HDL) having a major role in lipid transport and potent antimicrobial activity against a wide range of microbes. In this study, a complete CDS of 771 bp of Labeo rohita (rohu) ApoA-I (LrApoA-I) encoding a protein of 256 amino acids was amplified, cloned and sequenced. Tissue specific transcription analysis of LrApoA-I revealed its expression in a wide range of tissues, with a very high level of expression in liver and spleen. Ontogenic study of LrApoA-I expression showed presence of transcripts in milt and 3 h post-fertilization onwards in the larvae. The expression kinetics of LrApoA-I was studied upon infection with three different types of pathogens to elucidate its functional significance. Its expression was found to be up-regulated in the anterior kidney of L. rohita post-infection with Aeromonas hydrophila. Similarly following poly I:C (poly inosinic:cytidylic) stimulation, the transcript levels increased in both the anterior kidney and liver tissues. Significant up-regulation of LrApoA-I expression was observed in skin, mucous, liver and anterior kidney of the fish challenged with the ectoparasite Argulus siamensis. Immunomodulatory effect of recombinant LrApoA-I (rApoA-I) produced in Escherichia coli was demonstrated against A. hydrophila challenge in vivo. L. rohita administered with rApoA-I at a dose of 100 μg exhibited significantly higher protection (∼55%) upon challenge with A. hydrophila 12 h post-administration of the protein, in comparison to that observed in control group, along with higher level of expression of immune-related genes. The heightened expression of ApoA-I observed post-infection reflected its involvement in immune responses against a wide range of infections including bacterial, viral as well as parasitic pathogens. Our results also suggest the possibility of using rApoA-I as an immunostimulant, particularly rendering protection

  18. Expression of apolipoprotein A-I and A-II in rainbow trout reproductive tract and their possible role in antibacterial defence.

    PubMed

    Dietrich, Mariola A; Nynca, Joanna; Adamek, Mikołaj; Steinhagen, Dieter; Karol, Halina; Ciereszko, Andrzej

    2015-08-01

    Antimicrobial proteins such as apolipoproteins A (ApoA-I and ApoA-II) play an important role in the primary defence barrier in vertebrates including fish. The aims of the present study were to isolate and characterise rainbow trout seminal plasma ApoA-I and ApoA-II, to examine the mRNA expression of each apolipoprotein in testis and spermatic ducts, and to test the antibacterial properties of the apolipoproteins. Using a three-step isolation procedure consisting of ion-exchange chromatography, gel filtration and preparative SDS-PAGE, apolipoproteins were purified and identified as ApoA-I and ApoA-II. Both apolipoproteins were represented by several proteoforms. The expression of ApoA-I and ApoA-II mRNA in the reproductive tract and their antibacterial properties against Escherichia coli suggest that seminal apolipoproteins play an important role in innate immunity in the rainbow trout reproductive tract. The functions of seminal ApoA can be related to protection of sperm and reproductive tissue from microbial attack and to the maintenance of sperm membrane integrity.

  19. Influence of domain stability on the properties of human apolipoprotein E3 and E4 and mouse apolipoprotein E.

    PubMed

    Nguyen, David; Dhanasekaran, Padmaja; Nickel, Margaret; Mizuguchi, Chiharu; Watanabe, Mayu; Saito, Hiroyuki; Phillips, Michael C; Lund-Katz, Sissel

    2014-06-24

    The human apolipoprotein (apo) E4 isoform, which differs from wild-type apoE3 by the single amino acid substitution C112R, is associated with elevated risk of cardiovascular and Alzheimer’s diseases, but the molecular basis for this variation between isoforms is not understood. Human apoE is a two-domain protein comprising an N-terminal helix bundle and a separately folded C-terminal region. Here, we examine the concept that the ability of the protein to bind to lipid surfaces is influenced by the stability (or readiness to unfold) of these domains. The lipid-free structures and abilities to bind to lipid and lipoprotein particles of a series of human and mouse apoE variants with varying domain stabilities and domain–domain interactions are compared. As assessed by urea denaturation, the two domains are more unstable in apoE4 than in apoE3. To distinguish the contributions of the destabilization of each domain to the greater lipid-binding ability of apoE4, the properties of the apoE4 R61T and E255A variants, which have the same helix bundle stabilities but altered C-terminal domain stabilities, are compared. In these cases, the effects on lipid-binding properties are relatively minor, indicating that the destabilization of the helix bundle domain is primarily responsible for the enhanced lipid-binding ability of apoE4. Unlike human apoE, mouse apoE behaves essentially as a single domain, and its lipid-binding characteristics are more similar to those of apoE4. Together, the results show that the overall stability of the entire apoE molecule exerts a major influence on its lipid- and lipoprotein-binding properties.

  20. Apolipoprotein A-I Attenuates Palmitate-Mediated NF-κB Activation by Reducing Toll-Like Receptor-4 Recruitment into Lipid Rafts

    PubMed Central

    Tateya, Sanshiro; Schwartz, Jay; Tang, Chongren; Mitra, Poulami; Oram, John F.; Chait, Alan; Kim, Francis

    2012-01-01

    While high-density lipoprotein (HDL) is known to protect against a wide range of inflammatory stimuli, its anti-inflammatory mechanisms are not well understood. Furthermore, HDL's protective effects against saturated dietary fats have not been previously described. In this study, we used endothelial cells to demonstrate that while palmitic acid activates NF-κB signaling, apolipoprotein A–I, (apoA-I), the major protein component of HDL, attenuates palmitate-induced NF-κB activation. Further, vascular NF-κB signaling (IL-6, MCP-1, TNF-α) and macrophage markers (CD68, CD11c) induced by 24 weeks of a diabetogenic diet containing cholesterol (DDC) is reduced in human apoA-I overexpressing transgenic C57BL/6 mice compared to age-matched WT controls. Moreover, WT mice on DDC compared to a chow diet display increased gene expression of lipid raft markers such as Caveolin-1 and Flotillin-1, and inflammatory Toll-like receptors (TLRs) (TLR2, TLR4) in the vasculature. However apoA-I transgenic mice on DDC show markedly reduced expression of these genes. Finally, we show that in endothelial cells TLR4 is recruited into lipid rafts in response to palmitate, and that apoA-I prevents palmitate-induced TLR4 trafficking into lipid rafts, thereby blocking NF-κB activation. Thus, apoA-I overexpression might be a useful therapeutic tool against vascular inflammation. PMID:22479476

  1. Apolipoprotein modulation of streptococcal serum opacity factor activity against human plasma high-density lipoproteins.

    PubMed

    Rosales, Corina; Gillard, Baiba K; Courtney, Harry S; Blanco-Vaca, Francisco; Pownall, Henry J

    2009-08-25

    Human plasma HDL are the target of streptococcal serum opacity factor (SOF), a virulence factor that clouds human plasma. Recombinant (r) SOF transfers cholesteryl esters (CE) from approximately 400,000 HDL particles to a CE-rich microemulsion (CERM), forms a cholesterol-poor HDL-like particle (neo HDL), and releases lipid-free (LF) apo A-I. Whereas the rSOF reaction requires labile apo A-I, the modulation effects of other apos are not known. We compared the products and rates of the rSOF reaction against human HDL and HDL from mice overexpressing apos A-I and A-II. Kinetic studies showed that the reactivity of various HDL species is apo-specific. LpA-I reacts faster than LpA-I/A-II. Adding apos A-I and A-II inhibited the SOF reaction, an effect that was more profound for apo A-II. The rate of SOF-mediated CERM formation was slower against HDL from mice expressing human apos A-I and A-II than against WT mice HDL and slowest against HDL from apo A-II overexpressing mice. The lower reactivity of SOF against HDL containing human apos is due to the higher hydropathy of human apo A-I, particularly its C-terminus relative to mouse apo A-I, and the higher lipophilicity of human apo A-II. The SOF-catalyzed reaction is the first to target HDL rather than its transporters and receptors in a way that enhances reverse cholesterol transport (RCT). Thus, effects of apos on the SOF reaction are highly relevant. Our studies show that the "humanized" apo A-I-expressing mouse is a good animal model for studies of rSOF effects on RCT in vivo.

  2. Effect of lipid composition and packing on the adsorption of apolipoproteins to lipid monolayers

    SciTech Connect

    Ibdah, J.A.; Lund-Katz, S.; Phillips, M.C.

    1987-05-01

    The monolayer system has been used to study the effects of lipoprotein surface lipid composition and packing on the affinities of apolipoproteins for the surfaces of lipoprotein particles. The adsorption of apolipoproteins injected beneath lipid monolayers prepared with pure lipids or lipoprotein surface lipids is evaluated by monitoring the surface pressure of the film and the surface concentration (Gamma) of /sup 14/C-labelled apolipoprotein. At a given initial film pressure (..pi../sub i/) there is a higher adsorption of human apo A-I to unsaturated phosphatidylcholine (PC) monolayers compared to saturated PC monolayers (e.g., at ..pi../sub i/ = 10 mN/m, Gamma = 0.35 and 0.06 mg/m/sup 2/ for egg PC and distearoyl PC, respectively, with 3 x 10/sup -4/ mg/ml apo A-I in the subphase). In addition, adsorption of apo A-I is less to an egg sphingomyelin monolayer than to an egg PC monolayer. The adsorption of apo A-I to PC monolayers is decreased by addition of cholesterol. Generally, apo A-I adsorption diminishes as the lipid molecular area decreases. Apo A-I adsorbs more to monolayers prepared with HDL/sub 3/ surface lipids than with LDL surface lipids. These studies suggest that lipoprotein surface lipid composition and packing are crucial factors influencing the transfer and exchange of apolipoproteins among various lipoprotein classes during metabolism of lipoprotein particles.

  3. Several Human Liver Cell Expressed Apolipoproteins Complement HCV Virus Production with Varying Efficacy Conferring Differential Specific Infectivity to Released Viruses

    PubMed Central

    Doepke, Mandy; Vieyres, Gabrielle; Todt, Daniel; Wölk, Benno; Vondran, Florian W. R.; Geffers, Robert; Lauber, Chris; Kaderali, Lars; Penin, François; Pietschmann, Thomas

    2015-01-01

    Apolipoprotein E (ApoE), an exchangeable apolipoprotein, is necessary for production of infectious Hepatitis C virus (HCV) particles. However, ApoE is not the only liver-expressed apolipoprotein and the role of other apolipoproteins for production of infectious HCV progeny is incompletely defined. Therefore, we quantified mRNA expression of human apolipoproteins in primary human hepatocytes. Subsequently, cDNAs encoding apolipoproteins were expressed in 293T/miR-122 cells to explore if they complement HCV virus production in cells that are non-permissive due to limiting endogenous levels of human apolipoproteins. Primary human hepatocytes expressed high mRNA levels of ApoA1, A2, C1, C3, E, and H. ApoA4, A5, B, D, F, J, L1, L2, L3, L4, L6, M, and O were expressed at intermediate levels, and C2, C4, and L5 were not detected. All members of the ApoA and ApoC family of lipoproteins complemented HCV virus production in HCV transfected 293T/miR-122 cells, albeit with significantly lower efficacy compared with ApoE. In contrast, ApoD expression did not support production of infectious HCV. Specific infectivity of released particles complemented with ApoA family members was significantly lower compared with ApoE. Moreover, the ratio of extracellular to intracellular infectious virus was significantly higher for ApoE compared to ApoA2 and ApoC3. Since apolipoproteins complementing HCV virus production share amphipathic alpha helices as common structural features we altered the two alpha helices of ApoC1. Helix breaking mutations in both ApoC1 helices impaired virus assembly highlighting a critical role of alpha helices in apolipoproteins supporting HCV assembly. In summary, various liver expressed apolipoproteins with amphipathic alpha helices complement HCV virus production in human non liver cells. Differences in the efficiency of virus assembly, the specific infectivity of released particles, and the ratio between extracellular and intracellular infectivity point to

  4. Human liver apolipoprotein B-100 cDNA: complete nucleic acid and derived amino acid sequence.

    PubMed Central

    Law, S W; Grant, S M; Higuchi, K; Hospattankar, A; Lackner, K; Lee, N; Brewer, H B

    1986-01-01

    Human apolipoprotein B-100 (apoB-100), the ligand on low density lipoproteins that interacts with the low density lipoprotein receptor and initiates receptor-mediated endocytosis and low density lipoprotein catabolism, has been cloned, and the complete nucleic acid and derived amino acid sequences have been determined. ApoB-100 cDNAs were isolated from normal human liver cDNA libraries utilizing immunoscreening as well as filter hybridization with radiolabeled apoB-100 oligodeoxynucleotides. The apoB-100 mRNA is 14.1 kilobases long encoding a mature apoB-100 protein of 4536 amino acids with a calculated amino acid molecular weight of 512,723. ApoB-100 contains 20 potential glycosylation sites, and 12 of a total of 25 cysteine residues are located in the amino-terminal region of the apolipoprotein providing a potential globular structure of the amino terminus of the protein. ApoB-100 contains relatively few regions of amphipathic helices, but compared to other human apolipoproteins it is enriched in beta-structure. The delineation of the entire human apoB-100 sequence will now permit a detailed analysis of the conformation of the protein, the low density lipoprotein receptor binding domain(s), and the structural relationship between apoB-100 and apoB-48 and will provide the basis for the study of genetic defects in apoB-100 in patients with dyslipoproteinemias. PMID:3464946

  5. Membrane-induced conformational change in human apolipoprotein H.

    PubMed Central

    Wang, S X; Sun, Y T; Sui, S F

    2000-01-01

    The interaction of apolipoprotein H (Apo H) with lipid membrane has been considered to be a basic mechanism for the biological function of the protein. Previous reports have demonstrated that Apo H can interact only with membranes containing anionic phospholipids. Here we study the membrane-induced conformational change of Apo H by CD spectroscopy with two different model systems: anionic-phospholipid-containing liposomes [such as 1, 2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) and cardiolipin], and the water/methanol mixtures at moderately low pH, which mimic the micro-physicochemical environment near the membrane surface. It is found that Apo H undergoes a remarkable conformational change on interaction with liposomes containing anionic phospholipid. To interact with liposomes containing DMPG, there is a 6.8% increase in alpha-helix in the secondary structures; in liposomes containing cardiolipin, however, there is a 12.6% increase in alpha-helix and a 9% decrease in beta-sheet. The similar conformation change in Apo H can be induced by treatment with an appropriate mixture of water/methanol. The results indicate that the association of Apo H with membrane is correlated with a certain conformational change in the secondary structure of the protein. PMID:10794719

  6. Lipoprotein remodeling generates lipid-poor apolipoprotein A-I particles in human interstitial fluid

    PubMed Central

    Olszewski, Waldemar L.; Hattori, Hiroaki; Miller, Irina P.; Kujiraoka, Takeshi; Oka, Tomoichiro; Iwasaki, Tadao; Nanjee, M. Nazeem

    2013-01-01

    Although much is known about the remodeling of high density lipoproteins (HDLs) in blood, there is no information on that in interstitial fluid, where it might have a major impact on the transport of cholesterol from cells. We incubated plasma and afferent (prenodal) peripheral lymph from 10 healthy men at 37°C in vitro and followed the changes in HDL subclasses by nondenaturing two-dimensional crossed immunoelectrophoresis and size-exclusion chromatography. In plasma, there was always initially a net conversion of small pre-β-HDLs to cholesteryl ester (CE)-rich α-HDLs. By contrast, in lymph, there was only net production of pre-β-HDLs from α-HDLs. Endogenous cholesterol esterification rate, cholesteryl ester transfer protein (CETP) concentration, CE transfer activity, phospholipid transfer protein (PLTP) concentration, and phospholipid transfer activity in lymph averaged 5.0, 10.4, 8.2, 25.0, and 82.0% of those in plasma, respectively (all P < 0.02). Lymph PLTP concentration, but not phospholipid transfer activity, was positively correlated with that in plasma (r = +0.63, P = 0.05). Mean PLTP-specific activity was 3.5-fold greater in lymph, reflecting a greater proportion of the high-activity form of PLTP. These findings suggest that cholesterol esterification rate and PLTP specific activity are differentially regulated in the two matrices in accordance with the requirements of reverse cholesterol transport, generating lipid-poor pre-β-HDLs in the extracellular matrix for cholesterol uptake from neighboring cells and converting pre-β-HDLs to α-HDLs in plasma for the delivery of cell-derived CEs to the liver. PMID:23233540

  7. Glomerular autoimmune multicomponents of human lupus nephritis in vivo: α-enolase and annexin AI.

    PubMed

    Bruschi, Maurizio; Sinico, Renato Alberto; Moroni, Gabriella; Pratesi, Federico; Migliorini, Paola; Galetti, Maricla; Murtas, Corrado; Tincani, Angela; Madaio, Michael; Radice, Antonella; Franceschini, Franco; Trezzi, Barbara; Bianchi, Laura; Giallongo, Agata; Gatti, Rita; Tardanico, Regina; Scaloni, Andrea; D'Ambrosio, Chiara; Carnevali, Maria Luisa; Messa, Piergiorgio; Ravani, Pietro; Barbano, Giancarlo; Bianco, Beatrice; Bonanni, Alice; Scolari, Francesco; Martini, Alberto; Candiano, Giovanni; Allegri, Landino; Ghiggeri, Gian Marco

    2014-11-01

    Renal targets of autoimmunity in human lupus nephritis (LN) are unknown. We sought to identify autoantibodies and glomerular target antigens in renal biopsy samples from patients with LN and determine whether the same autoantibodies can be detected in circulation. Glomeruli were microdissected from biopsy samples of 20 patients with LN and characterized by proteomic techniques. Serum samples from large cohorts of patients with systemic lupus erythematosus (SLE) with and without LN and other glomerulonephritides were tested. Glomerular IgGs recognized 11 podocyte antigens, with reactivity varying by LN pathology. Notably, IgG2 autoantibodies against α-enolase and annexin AI were detected in 11 and 10 of the biopsy samples, respectively, and predominated over other autoantibodies. Immunohistochemistry revealed colocalization of α-enolase or annexin AI with IgG2 in glomeruli. High levels of serum anti-α-enolase (>15 mg/L) IgG2 and/or anti-annexin AI (>2.7 mg/L) IgG2 were detected in most patients with LN but not patients with other glomerulonephritides, and they identified two cohorts: patients with high anti-α-enolase/low anti-annexin AI IgG2 and patients with low anti-α-enolase/high anti-annexin AI IgG2. Serum levels of both autoantibodies decreased significantly after 12 months of therapy for LN. Anti-α-enolase IgG2 recognized specific epitopes of α-enolase and did not cross-react with dsDNA. Furthermore, nephritogenic monoclonal IgG2 (clone H147) derived from lupus-prone MRL-lpr/lpr mice recognized human α-enolase, suggesting homology between animal models and human LN. These data show a multiantibody composition in LN, where IgG2 autoantibodies against α-enolase and annexin AI predominate in the glomerulus and can be detected in serum.

  8. Glomerular Autoimmune Multicomponents of Human Lupus Nephritis In Vivo: α-Enolase and Annexin AI

    PubMed Central

    Bruschi, Maurizio; Sinico, Renato Alberto; Moroni, Gabriella; Pratesi, Federico; Migliorini, Paola; Galetti, Maricla; Murtas, Corrado; Tincani, Angela; Madaio, Michael; Radice, Antonella; Franceschini, Franco; Trezzi, Barbara; Bianchi, Laura; Giallongo, Agata; Gatti, Rita; Tardanico, Regina; Scaloni, Andrea; D’Ambrosio, Chiara; Carnevali, Maria Luisa; Messa, Piergiorgio; Ravani, Pietro; Barbano, Giancarlo; Bianco, Beatrice; Bonanni, Alice; Scolari, Francesco; Martini, Alberto; Candiano, Giovanni; Allegri, Landino

    2014-01-01

    Renal targets of autoimmunity in human lupus nephritis (LN) are unknown. We sought to identify autoantibodies and glomerular target antigens in renal biopsy samples from patients with LN and determine whether the same autoantibodies can be detected in circulation. Glomeruli were microdissected from biopsy samples of 20 patients with LN and characterized by proteomic techniques. Serum samples from large cohorts of patients with systemic lupus erythematosus (SLE) with and without LN and other glomerulonephritides were tested. Glomerular IgGs recognized 11 podocyte antigens, with reactivity varying by LN pathology. Notably, IgG2 autoantibodies against α-enolase and annexin AI were detected in 11 and 10 of the biopsy samples, respectively, and predominated over other autoantibodies. Immunohistochemistry revealed colocalization of α-enolase or annexin AI with IgG2 in glomeruli. High levels of serum anti–α-enolase (>15 mg/L) IgG2 and/or anti-annexin AI (>2.7 mg/L) IgG2 were detected in most patients with LN but not patients with other glomerulonephritides, and they identified two cohorts: patients with high anti–α-enolase/low anti-annexin AI IgG2 and patients with low anti–α-enolase/high anti-annexin AI IgG2. Serum levels of both autoantibodies decreased significantly after 12 months of therapy for LN. Anti–α-enolase IgG2 recognized specific epitopes of α-enolase and did not cross-react with dsDNA. Furthermore, nephritogenic monoclonal IgG2 (clone H147) derived from lupus-prone MRL-lpr/lpr mice recognized human α-enolase, suggesting homology between animal models and human LN. These data show a multiantibody composition in LN, where IgG2 autoantibodies against α-enolase and annexin AI predominate in the glomerulus and can be detected in serum. PMID:24790181

  9. Human Apolipoprotein A-I-Derived Amyloid: Its Association with Atherosclerosis

    PubMed Central

    Ramella, Nahuel A.; Rimoldi, Omar J.; Prieto, Eduardo D.; Schinella, Guillermo R.; Sanchez, Susana A.; Jaureguiberry, María S.; Vela, María E.

    2011-01-01

    Amyloidoses constitute a group of diseases in which soluble proteins aggregate and deposit extracellularly in tissues. Nonhereditary apolipoprotein A-I (apoA-I) amyloid is characterized by deposits of nonvariant protein in atherosclerotic arteries. Despite being common, little is known about the pathogenesis and significance of apoA-I deposition. In this work we investigated by fluorescence and biochemical approaches the impact of a cellular microenvironment associated with chronic inflammation on the folding and pro-amyloidogenic processing of apoA-I. Results showed that mildly acidic pH promotes misfolding, aggregation, and increased binding of apoA-I to extracellular matrix elements, thus favoring protein deposition as amyloid like-complexes. In addition, activated neutrophils and oxidative/proteolytic cleavage of the protein give rise to pro amyloidogenic products. We conclude that, even though apoA-I is not inherently amyloidogenic, it may produce non hereditary amyloidosis as a consequence of the pro-inflammatory microenvironment associated to atherogenesis. PMID:21811627

  10. Apolipoprotein A-I, an antimicrobial protein in Oncorhynchus mykiss: evaluation of its expression in primary defence barriers and plasma levels in sick and healthy fish.

    PubMed

    Villarroel, Franz; Bastías, Adriana; Casado, Alin; Amthauer, Rodolfo; Concha, Margarita I

    2007-07-01

    Antimicrobial proteins and peptides play an important role in the primary defence barriers in vertebrates and invertebrates. In a previous study it was shown that high-density lipoprotein (HDL) and its major apolipoproteins, ApoA-I and ApoA-II display antimicrobial activity in the carp (Cyprinus carpio L.). The aim of this study was to evaluate if ApoA-I conserves this defensive function in a salmonid fish like the rainbow trout, in spite of the low level of primary sequence conservation between fish ApoA-I. Here it is shown that trout ApoA-I displays an antimicrobial activity in the micromolar range against Gram positive and Gram negative bacteria, including some fish pathogens. In addition, its expression was also demonstrated by immunohistochemistry and RT-PCR in epidermis, gills and intestinal mucosa, which constitute the main primary defence barriers in fish. Finally, no significant difference in the hepatic expression and plasma levels of this abundant apolipoprotein was found in groups of healthy and diseased fish, in clear contrast with mammals where ApoA-I have been considered a negative acute phase reactant. These findings suggest that ApoA-I could constitute an important innate immunity effector in trout and perhaps other teleost fish. PMID:17391986

  11. Apolipoproteins A-I and A-II are potentially important effectors of innate immunity in the teleost fish Cyprinus carpio.

    PubMed

    Concha, Margarita I; Smith, Valerie J; Castro, Karina; Bastías, Adriana; Romero, Alex; Amthauer, Rodolfo J

    2004-07-01

    We have previously shown that high density lipoprotein is the most abundant protein in the carp plasma and displays bactericidal activity in vitro. Therefore the aim of this study was to analyze the contribution of its principal apolipoproteins, apoA-I and apoA-II, in defense. Both apolipoproteins were isolated by a two step procedure involving affinity and gel filtration chromatography and were shown to display bactericidal and/or bacteriostatic activity in the micromolar range against Gram-positive and Gram-negative bacteria, including some fish pathogens. In addition, a cationic peptide derived from the C-terminal region of carp apoA-I was synthesized and shown to possess antimicrobial activity (EC(50) = 3-6 micro m) against Planococcus citreus. This peptide was also able to potentiate the inhibitory effect of lysozyme in a radial diffusion assay at subinhibitory concentrations of both effectors. Finally, limited proteolysis of HDL-associated apoA-I with chymotrypsin in vitro was shown to generate a major truncated fragment, which indicates that apoA-I peptides liberated in vivo through a regulated proteolysis could also be involved in innate immunity.

  12. An apolipoprotein influencing triglycerides in humans and mice revealed by comparative sequencing.

    PubMed

    Pennacchio, L A; Olivier, M; Hubacek, J A; Cohen, J C; Cox, D R; Fruchart, J C; Krauss, R M; Rubin, E M

    2001-10-01

    Comparison of genomic DNA sequences from human and mouse revealed a new apolipoprotein (APO) gene (APOAV) located proximal to the well-characterized APOAI/CIII/AIV gene cluster on human 11q23. Mice expressing a human APOAV transgene showed a decrease in plasma triglyceride concentrations to one-third of those in control mice; conversely, knockout mice lacking Apoav had four times as much plasma triglycerides as controls. In humans, single nucleotide polymorphisms (SNPs) across the APOAV locus were found to be significantly associated with plasma triglyceride levels in two independent studies. These findings indicate that APOAV is an important determinant of plasma triglyceride levels, a major risk factor for coronary artery disease.

  13. An experimental study on amelioration of dyslipidemia-induced atherosclesis by Clematichinenoside through regulating Peroxisome proliferator-activated receptor-α mediated apolipoprotein A-I, A-II and C-III.

    PubMed

    Liu, Chao; Guo, Qianqian; Lu, Mengchen; Li, Yunman

    2015-08-15

    Prevention or amelioration the prevalence of atherosclerosis has been an effective strategy in the management of cardiovascular diseases. The aim of the study was to scrutinize the effect of Clematichinenoside (AR) on dyslipidemia-induced atherosclerosis and explore its capability on expression of Peroxisome proliferator-activated receptor-α (PPAR-alpha), apolipoprotein A-I (APOA1) and A-II (APOA2), and suppression of apolipoprotein C-III (APOC3) genes and proteins. In the present study, we investigated atherosclerosis effect of AR using a combination of high-fat diet and balloon injury model in rabbits. The levels of biochemical indicators were evaluated in plasma, liver and HepG2 cells using immunoassay technology. In order to expose the underlying mechanism, we evaluated the regulation of PPAR-alpha, APOA1, APOA2 and APOC3 expressions by AR, and we further evaluated the interactions between them after transfection with shRNA (shPPAR-alpha) and, the action of PPAR-alpha in HepG2 cells. We could find that AR markedly promoted the PPAR-alpha transfer from cytoplasm to nucleus which resulted in the alteration of APOA1, APOA2 and APOC3 expressions in HepG2 cells. Moreover, AR significantly reduced total cholesterol, triglycerides and low-density lipoprotein cholesterol (LDL-C) levels, and elevated high-density lipoprotein cholesterol (HDL-C) level, which play an important role in dyslipidemia-induced atherosclerosis. In conclusion, AR ameliorated atherosclerosis via the regulation of hepatic lipid metabolism, and AR also contributed to the activation of PPAR-alpha, APOA1, APOA2 and APOC3. Therefore, AR could be a potential therapeutic agent in the treatment of atherosclerosis.

  14. Lifelong expression of apolipoprotein D in the human brainstem: correlation with reduced age-related neurodegeneration.

    PubMed

    Navarro, Ana; Méndez, Elena; Diaz, Celso; del Valle, Eva; Martínez-Pinilla, Eva; Ordóñez, Cristina; Tolivia, Jorge

    2013-01-01

    The lipocalin apolipoprotein D (Apo D) is upregulated in peripheral nerves following injury and in regions of the central nervous system, such as the cerebral cortex, hippocampus, and cerebellum, during aging and progression of certain neurological diseases. In contrast, few studies have examined Apo D expression in the brainstem, a region necessary for survival and generally less prone to age-related degeneration. We measured Apo D expression in whole human brainstem lysates by slot-blot and at higher spatial resolution by quantitative immunohistochemistry in eleven brainstem nuclei (the 4 nuclei of the vestibular nuclear complex, inferior olive, hypoglossal nucleus, oculomotor nucleus, facial motor nucleus, nucleus of the solitary tract, dorsal motor nucleus of the vagus nerve, and Roller`s nucleus). In contrast to cortex, hippocampus, and cerebellum, apolipoprotein D was highly expressed in brainstem tissue from subjects (N = 26, 32-96 years of age) with no history of neurological disease, and expression showed little variation with age. Expression was significantly stronger in somatomotor nuclei (hypoglossal, oculomotor, facial) than visceromotor or sensory nuclei. Both neurons and glia expressed Apo D, particularly neurons with larger somata and glia in the periphery of these brainstem centers. Immunostaining was strongest in the neuronal perinuclear region and absent in the nucleus. We propose that strong brainstem expression of Apo D throughout adult life contributes to resistance against neurodegenerative disease and age-related degeneration, possibly by preventing oxidative stress and ensuing lipid peroxidation.

  15. Lifelong Expression of Apolipoprotein D in the Human Brainstem: Correlation with Reduced Age-Related Neurodegeneration

    PubMed Central

    Navarro, Ana; Méndez, Elena; Diaz, Celso; del Valle, Eva; Martínez-Pinilla, Eva; Ordóñez, Cristina; Tolivia, Jorge

    2013-01-01

    The lipocalin apolipoprotein D (Apo D) is upregulated in peripheral nerves following injury and in regions of the central nervous system, such as the cerebral cortex, hippocampus, and cerebellum, during aging and progression of certain neurological diseases. In contrast, few studies have examined Apo D expression in the brainstem, a region necessary for survival and generally less prone to age-related degeneration. We measured Apo D expression in whole human brainstem lysates by slot-blot and at higher spatial resolution by quantitative immunohistochemistry in eleven brainstem nuclei (the 4 nuclei of the vestibular nuclear complex, inferior olive, hypoglossal nucleus, oculomotor nucleus, facial motor nucleus, nucleus of the solitary tract, dorsal motor nucleus of the vagus nerve, and Roller`s nucleus). In contrast to cortex, hippocampus, and cerebellum, apolipoprotein D was highly expressed in brainstem tissue from subjects (N = 26, 32−96 years of age) with no history of neurological disease, and expression showed little variation with age. Expression was significantly stronger in somatomotor nuclei (hypoglossal, oculomotor, facial) than visceromotor or sensory nuclei. Both neurons and glia expressed Apo D, particularly neurons with larger somata and glia in the periphery of these brainstem centers. Immunostaining was strongest in the neuronal perinuclear region and absent in the nucleus. We propose that strong brainstem expression of Apo D throughout adult life contributes to resistance against neurodegenerative disease and age-related degeneration, possibly by preventing oxidative stress and ensuing lipid peroxidation. PMID:24167586

  16. Transgenic mice expressing high plasma concentrations of human apolipoprotein B100 and lipoprotein(a).

    PubMed Central

    Linton, M F; Farese, R V; Chiesa, G; Grass, D S; Chin, P; Hammer, R E; Hobbs, H H; Young, S G

    1993-01-01

    The B apolipoproteins, apo-B48 and apo-B100, are key structural proteins in those classes of lipoproteins considered to be atherogenic [e.g., chylomicron remnants, beta-VLDL, LDL, oxidized LDL, and Lp(a)]. Here we describe the development of transgenic mice expressing high levels of human apo-B48 and apo-B100. A 79.5-kb human genomic DNA fragment containing the entire human apo-B gene was isolated from a P1 bacteriophage library and microinjected into fertilized mouse eggs. 16 transgenic founders expressing human apo-B were generated, and the animals with the highest expression had plasma apo-B100 levels nearly as high as those of normolipidemic humans (approximately 50 mg/dl). The human apo-B100 in transgenic mouse plasma was present largely in lipoproteins of the LDL class as shown by agarose gel electrophoresis, chromatography on a Superose 6 column, and density gradient ultracentrifugation. When the human apo-B transgenic founders were crossed with transgenic mice expressing human apo(a), the offspring that expressed both transgenes had high plasma levels of human Lp(a). Both the human apo-B and Lp(a) transgenic mice will be valuable resources for studying apo-B metabolism and the role of apo-B and Lp(a) in atherosclerosis. Images PMID:8254057

  17. Characterisation of mRNAs encoding the precursor for human apolipoprotein CI.

    PubMed Central

    Knott, T J; Robertson, M E; Priestley, L M; Urdea, M; Wallis, S; Scott, J

    1984-01-01

    cDNA clones encoding human apolipoprotein CI have been isolated from an adult liver cDNA library. Apo CI mRNA was shown to have two species of approximately 580 and 560 bases by RNA blot hybridisation. The intracellular precursor of apo CI was inferred from the cDNA sequence to be an 83 amino acid polypeptide consisting of the 57 residue mature protein and an additional 26 residue amino terminal signal peptide. The 5' untranslated regions of the messages are 63 and 40 bases as determined by primer extension and the 3' untranslated region 111 bases. A polyadenylation signal is situated 10 bases 3' of the poly(A) tall. The mRNA level of apo CI in human liver was significantly greater than that of apo All and apo E. Images PMID:6328444

  18. Dual Actions of Apolipoprotein A-I on Glucose-Stimulated Insulin Secretion and Insulin-Independent Peripheral Tissue Glucose Uptake Lead to Increased Heart and Skeletal Muscle Glucose Disposal.

    PubMed

    Domingo-Espín, Joan; Lindahl, Maria; Nilsson-Wolanin, Oktawia; Cushman, Samuel W; Stenkula, Karin G; Lagerstedt, Jens O

    2016-07-01

    Apolipoprotein A-I (apoA-I) of HDL is central to the transport of cholesterol in circulation. ApoA-I also provides glucose control with described in vitro effects of apoA-I on β-cell insulin secretion and muscle glucose uptake. In addition, apoA-I injections in insulin-resistant diet-induced obese (DIO) mice lead to increased glucose-stimulated insulin secretion (GSIS) and peripheral tissue glucose uptake. However, the relative contribution of apoA-I as an enhancer of GSIS in vivo and as a direct stimulator of insulin-independent glucose uptake is not known. Here, DIO mice with instant and transient blockade of insulin secretion were used in glucose tolerance tests and in positron emission tomography analyses. Data demonstrate that apoA-I to an equal extent enhances GSIS and acts as peripheral tissue activator of insulin-independent glucose uptake and verify skeletal muscle as an apoA-I target tissue. Intriguingly, our analyses also identify the heart as an important target tissue for the apoA-I-stimulated glucose uptake, with potential implications in diabetic cardiomyopathy. Explorations of apoA-I as a novel antidiabetic drug should extend to treatments of diabetic cardiomyopathy and other cardiovascular diseases in patients with diabetes. PMID:27207515

  19. Case report: A novel apolipoprotein A-I missense mutation apoA-I (Arg149Ser)Boston associated with decreased lecithin-cholesterol acyltransferase activation and cellular cholesterol efflux.

    PubMed

    Anthanont, Pimjai; Asztalos, Bela F; Polisecki, Eliana; Zachariah, Benoy; Schaefer, Ernst J

    2015-01-01

    We report a novel heterozygous apolipoprotein A-I (apoA-I) missense mutation (c.517C>A, p.Arg149Ser, designated as apoA-IBoston) in a 67-year-old woman and her 2 sons, who had mean serum high-density lipoprotein (HDL) cholesterol, apoA-I, and apoA-I in very large α-1 HDL that were 10%, 35%, and 16% of normal, respectively (all P < .05). The percentage of HDL cholesterol in the esterified form was also significantly (P < .05) reduced to 52% of control values. Cholesteryl ester tranfer protein (CETP) activity was normal. The mean global, adenosine triphosphate (ATP)-binding cassette transporter A1 and scavenger receptor B type I-mediated cellular cholesterol efflux capacity in apoB-depleted serum from affected family members were 41%, 37%, 47%, 54%, and 48% of control values, respectively (all P < .05). lecithin-cholesterol acyltransferase (LCAT) activity in plasma was 71% of controls, whereas in the cell-based assay, it was 73% of control values (P < .05). The data indicate that this novel apoA-I missense is associated with markedly decreased levels of HDL cholesterol and very large α-1 HDL, as well as decreased serum cellular cholesterol efflux and LCAT activity, but not with premature coronary heart disease, similar to other apoA-I mutations that have been associated with decreased LCAT activity.

  20. Dual Actions of Apolipoprotein A-I on Glucose-Stimulated Insulin Secretion and Insulin-Independent Peripheral Tissue Glucose Uptake Lead to Increased Heart and Skeletal Muscle Glucose Disposal.

    PubMed

    Domingo-Espín, Joan; Lindahl, Maria; Nilsson-Wolanin, Oktawia; Cushman, Samuel W; Stenkula, Karin G; Lagerstedt, Jens O

    2016-07-01

    Apolipoprotein A-I (apoA-I) of HDL is central to the transport of cholesterol in circulation. ApoA-I also provides glucose control with described in vitro effects of apoA-I on β-cell insulin secretion and muscle glucose uptake. In addition, apoA-I injections in insulin-resistant diet-induced obese (DIO) mice lead to increased glucose-stimulated insulin secretion (GSIS) and peripheral tissue glucose uptake. However, the relative contribution of apoA-I as an enhancer of GSIS in vivo and as a direct stimulator of insulin-independent glucose uptake is not known. Here, DIO mice with instant and transient blockade of insulin secretion were used in glucose tolerance tests and in positron emission tomography analyses. Data demonstrate that apoA-I to an equal extent enhances GSIS and acts as peripheral tissue activator of insulin-independent glucose uptake and verify skeletal muscle as an apoA-I target tissue. Intriguingly, our analyses also identify the heart as an important target tissue for the apoA-I-stimulated glucose uptake, with potential implications in diabetic cardiomyopathy. Explorations of apoA-I as a novel antidiabetic drug should extend to treatments of diabetic cardiomyopathy and other cardiovascular diseases in patients with diabetes.

  1. Patterns of association between genetic variability in apolipoprotein (apo) B, apo AI-CIII-AIV, and cholesterol ester transfer protein gene regions and quantitative variation in lipid and lipoprotein traits: influence of gender and exogenous hormones.

    PubMed Central

    Kessling, A; Ouellette, S; Bouffard, O; Chamberland, A; Bétard, C; Selinger, E; Xhignesse, M; Lussier-Cacan, S; Davignon, J

    1992-01-01

    Patterns of RFLP association were studied, to identify gene regions influencing quantitative variation in lipid and lipoprotein traits (coronary artery disease [CAD] risk factors or metabolically related traits). Subjects (118 female and 229 male; age 20-59 years) were selected for health. Multiple RFLPs were used to sample variability in regions around genes for apolipoprotein (apo) B (restriction enzymes HincII, PvuII, EcoRI, and XbaI), apo AI-CIII-AIV (BamHI, XmnI, TaqI, PstI, SstI, and PvuII) and cholesterol ester transfer protein (TaqI). Separate analyses were done by gender. The sample was truncated at mean +/- 4 SD, to remove extreme outliers. There was no significant gender difference in RFLP genotype frequency distribution. After trait-level adjustment to maximize removal of concomitant variability, analysis of variance was used to estimate the percentage trait phenotypic variance explained by measured variability in the gene regions studied. Fewer gene regions were involved in men, with less influence on quantitative trait variation than in women, in whom hormone use affected association patterns. Gender differences imply that pooling genders or adjusting data for gender effects removes genetic information and should be avoided. The association patterns show that variability around the candidate genes modulates trait levels: the genes are contributors to the genetics of CAD risk variables in a healthy sample. PMID:1346081

  2. Case report: A novel apolipoprotein A-I missense mutation apoA-I (Arg149Ser)Boston associated with decreased lecithin-cholesterol acyltransferase activation and cellular cholesterol efflux.

    PubMed

    Anthanont, Pimjai; Asztalos, Bela F; Polisecki, Eliana; Zachariah, Benoy; Schaefer, Ernst J

    2015-01-01

    We report a novel heterozygous apolipoprotein A-I (apoA-I) missense mutation (c.517C>A, p.Arg149Ser, designated as apoA-IBoston) in a 67-year-old woman and her 2 sons, who had mean serum high-density lipoprotein (HDL) cholesterol, apoA-I, and apoA-I in very large α-1 HDL that were 10%, 35%, and 16% of normal, respectively (all P < .05). The percentage of HDL cholesterol in the esterified form was also significantly (P < .05) reduced to 52% of control values. Cholesteryl ester tranfer protein (CETP) activity was normal. The mean global, adenosine triphosphate (ATP)-binding cassette transporter A1 and scavenger receptor B type I-mediated cellular cholesterol efflux capacity in apoB-depleted serum from affected family members were 41%, 37%, 47%, 54%, and 48% of control values, respectively (all P < .05). lecithin-cholesterol acyltransferase (LCAT) activity in plasma was 71% of controls, whereas in the cell-based assay, it was 73% of control values (P < .05). The data indicate that this novel apoA-I missense is associated with markedly decreased levels of HDL cholesterol and very large α-1 HDL, as well as decreased serum cellular cholesterol efflux and LCAT activity, but not with premature coronary heart disease, similar to other apoA-I mutations that have been associated with decreased LCAT activity. PMID:26073399

  3. Orphan nuclear receptor Nur77 participates in human apolipoprotein A5 gene expression

    SciTech Connect

    Song, Kwang-Hoon

    2010-01-29

    The orphan nuclear receptor Nur77 (NR4A1) has been reported to play a crucial role in the modulation of diverse metabolic processes in liver. Here, we reported the identification of human apolipoprotein A5 (ApoA5), which implicated in lowering plasma triglyceride levels, as a novel target gene of Nur77. Nur77 induced the human ApoA5 promoter activity. Using 5'-deletion and mutagenesis of human ApoA5 promoter analysis and chromatin immunoprecipitation assays, it was shown that Nur77 directly regulated human ApoA5 gene expression by binding to a Nur77 response element (AAAGGTCA) located in the proximal human ApoA5 promoter region. In addition, we demonstrated that blocking of Nur77 transcriptional activity via overexpression of dominant negative Nur77 suppressed human ApoA5 promoter activity and mRNA expression in human hepatoma cells, HepG2. Taken together, our results demonstrated that Nur77 is a novel regulator of human ApoA5 gene expression and provide a new insight into the role of this orphan nuclear receptor in lipoprotein metabolism and triglyceride homeostasis.

  4. Epigenetic effectiveness of complete carcinogens: specific interactions of polycyclic aromatic hydrocarbons and aminoazo dyes with cholesterol and apolipoprotein A-I.

    PubMed

    Contag, Bodo

    2005-01-01

    During a co-precipitation of cholesterol (Chol) and slight amounts of polycyclic aromatic hydrocarbons (PAHs) or aminoazo dyes (AZOs) in aqueous albumin solution, complex particles are formed; on their surfaces apolipoproteins with an amphipathic alpha-helix (e.g. apoA-I) are more or less firmly adsorbed. An efficacy index can be calculated from the strength of the hydrophobic interactions between apoA-I and the [Chol/PAH]- or [Chol/AZO]-complex, and the solubility of the PAH or AZO in an aqueous medium, which correlates to the carcinogenicity of these compounds. A short-term test for PAHs and AZOs is described, in which the efficacy index can be determined in the simplest manner without any great expenditure on equipment. The previous results suggest that the parent compounds of the PAHs and AZOs can be involved in a specific interaction with cholesterol-domains of the plasma membrane of a cell. The changes in membrane fluidity and architecture caused by these specific interactions could modulate the distribution and/or activity of membrane proteins which are critical to the regulation of cellular proliferation.

  5. Effects of weight-loss by exercise and by diet on apolipoproteins A-I and A-II and the particle-size distribution of high-density lipoproteins in men.

    PubMed

    Williams, P T; Krauss, R M; Vranizan, K M; Albers, J J; Wood, P D

    1992-04-01

    We studied separately the effects of weight-loss by dieting or by running on apolipoprotein (apo) A-I, apo A-II, and high-density lipoprotein (HDL) subfractions in sedentary, moderately overweight men assigned at random into three groups: exercise without calorie restriction, calorie restriction without exercise, and control. The absorbance of protein-stained polyacrylamide gradient gels was used as an index of mass concentrations for five HDL subclasses that have been identified by their particle sizes: HDL3c (7.2 to 7.8 nm), HDL3b (7.8 to 8.2 nm), HDL3a (8.2 to 8.8 nm), HDL2a (8.8 to 9.7 nm), and HDL2b (9.7 to 12.9 nm). During the 1-year trial, the exercisers ran (mean +/- SD) 15.6 +/- 9.1 km/wk, and the dieters reported eating 340 +/- 71 fewer calories per day than at baseline. Total body weight and fat weight were both reduced significantly more in dieters (-7.2 +/- 4.1 and -6.2 +/- 4.1 kg, respectively) and in exercisers (-4.0 +/- 3.9 and -4.6 +/- 3.5 kg) than in controls (0.6 +/- 3.7 and -0.7 +/- 2.7 kg). As compared with mean changes in controls, exercisers and dieters each decreased HDL3b and increased HDL2b. Exercisers also significantly increased plasma apo A-I concentrations. Analysis of covariance was used to statistically adjust the mean lipoprotein changes for the effects of weight-loss. The adjustment eliminated the significant reductions in HDL3b and the significant increases in HDL2b in exercisers and dieters, and it eliminated the significant increase in apo A-I in exercisers. When adjusted, the dieters' mean changes in HDL2b had significantly decreased relative to those of both exercisers and controls.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. A new cryptic cationic antimicrobial peptide from human apolipoprotein E with antibacterial activity and immunomodulatory effects on human cells.

    PubMed

    Pane, Katia; Sgambati, Valeria; Zanfardino, Anna; Smaldone, Giovanni; Cafaro, Valeria; Angrisano, Tiziana; Pedone, Emilia; Di Gaetano, Sonia; Capasso, Domenica; Haney, Evan F; Izzo, Viviana; Varcamonti, Mario; Notomista, Eugenio; Hancock, Robert E W; Di Donato, Alberto; Pizzo, Elio

    2016-06-01

    Cationic antimicrobial peptides (AMPs) possess fast and broad-spectrum activity against both Gram-negative and Gram-positive bacteria, as well as fungi. It has become increasingly evident that many AMPs, including those that derive from fragments of host proteins, are multifunctional and able to mediate various immunomodulatory functions and angiogenesis. Among these, synthetic apolipoprotein-derived peptides are safe and well tolerated in humans and have emerged as promising candidates in the treatment of various inflammatory conditions. Here, we report the characterization of a new AMP corresponding to residues 133-150 of human apolipoprotein E. Our results show that this peptide, produced either by chemical synthesis or by recombinant techniques in Escherichia coli, possesses a broad-spectrum antibacterial activity. As shown for several other AMPs, ApoE (133-150) is structured in the presence of TFE and of membrane-mimicking agents, like SDS, or bacterial surface lipopolysaccharide (LPS), and an anionic polysaccharide, alginate, which mimics anionic capsular exo-polysaccharides of several pathogenic microorganisms. Noteworthy, ApoE (133-150) is not toxic toward several human cell lines and triggers a significant innate immune response, assessed either as decreased expression levels of proinflammatory cytokines in differentiated THP-1 monocytic cells or by the induction of chemokines released from PBMCs. This novel bioactive AMP also showed a significant anti-inflammatory effect on human keratinocytes, suggesting its potential use as a model for designing new immunomodulatory therapeutics. PMID:27028511

  7. Genetic studies of human apolipoproteins. XX. Genetic polymorphism of apolipoprotein J and its impact on quantitative lipid traits in normolipidemic subjects.

    PubMed Central

    Kamboh, M I; Harmony, J A; Sepehrnia, B; Nwankwo, M; Ferrell, R E

    1991-01-01

    Apolipoprotein J (apo J) is a newly identified member of a growing family of proteins associated with various lipoprotein particles. Apo J is a glycoprotein which exists in the plasma associated with high-density lipoprotein subfractions which also contain apo A-I and cholesteryl ester transfer protein (CETP). We have investigated the possible existence of genetic polymorphism at the apo J structural locus and have evaluated its role in lipid metabolism. By employing isoelectric focusing and immunoblotting techniques, we have screened plasma or serum samples from six population groups: U.S. whites, Amerindians, Eskimos, New Guineans, U.S. blacks, and Nigerian blacks. Apo J revealed a common two-allele polymorphism only in populations with African ancestry and was found to be monomorphic in all other population groups tested. The genetic basis of the two alleles designated--APO J*1 and APO J*2, at a single structural locus, apo J-- was confirmed in a large number of segregating families. In the U.S. blacks, the frequencies of the APO J*1 and APO J*2 alleles were .76 and .24, respectively, and in the Nigerian blacks these values were .72 and .28, respectively. In addition, a single example of a rare allele designated APO J*3 was also encountered in the U.S. black sample. In Nigerian blacks, the apo J polymorphism's impact on seven quantitative lipid traits--total cholesterol, LDL-cholesterol, HDL-cholesterol, HDL3-cholesterol, HDL2-cholesterol, VLDL-cholesterol, and triglycerides--was investigated. No significant impact of the apo J polymorphism was observed for any of these lipid traits. Images Figure 1 Figure 2 PMID:1746550

  8. Apolipoprotein A-I glycation by glucose and reactive aldehydes alters phospholipid affinity but not cholesterol export from lipid-laden macrophages.

    PubMed

    Brown, Bronwyn E; Nobecourt, Estelle; Zeng, Jingmin; Jenkins, Alicia J; Rye, Kerry-Anne; Davies, Michael J

    2013-01-01

    Increased protein glycation in people with diabetes may promote atherosclerosis. This study examined the effects of non-enzymatic glycation on the association of lipid-free apolipoproteinA-I (apoA-I) with phospholipid, and cholesterol efflux from lipid-loaded macrophages to lipid-free and lipid-associated apoA-I. Glycation of lipid-free apoA-I by methylglyoxal and glycolaldehyde resulted in Arg, Lys and Trp loss, advanced glycation end-product formation and protein cross-linking. The association of apoA-I glycated by glucose, methylglyoxal or glycolaldehyde with phospholipid multilamellar vesicles was impaired in a glycating agent dose-dependent manner, with exposure of apoA-I to both 30 mM glucose (42% decrease in kslow) and 3 mM glycolaldehyde (50% decrease in kfast, 60% decrease in kslow) resulting is significantly reduced affinity. Cholesterol efflux to control or glycated lipid-free apoA-I, or discoidal reconstituted HDL containing glycated apoA-I (drHDL), was examined using cholesterol-loaded murine (J774A.1) macrophages treated to increase expression of ATP binding cassette transporters A1 (ABCA1) or G1 (ABCG1). Cholesterol efflux from J774A.1 macrophages to glycated lipid-free apoA-I via ABCA1 or glycated drHDL via an ABCG1-dependent mechanism was unaltered, as was efflux to minimally modified apoA-I from people with Type 1 diabetes, or controls. Changes to protein structure and function were prevented by the reactive carbonyl scavenger aminoguanidine. Overall these studies demonstrate that glycation of lipid-free apoA-I, particularly late glycation, modifies its structure, its capacity to bind phospholipids and but not ABCA1- or ABCG1-dependent cholesterol efflux from macrophages.

  9. Cholesterol-Independent Suppression of Lymphocyte Activation, Autoimmunity, and Glomerulonephritis by Apolipoprotein A-I in Normocholesterolemic Lupus-Prone Mice.

    PubMed

    Black, Leland L; Srivastava, Roshni; Schoeb, Trenton R; Moore, Ray D; Barnes, Stephen; Kabarowski, Janusz H

    2015-11-15

    Apolipoprotein (Apo)A-I, the major lipid-binding protein of high-density lipoprotein, can prevent autoimmunity and suppress inflammation in hypercholesterolemic mice by attenuating lymphocyte cholesterol accumulation and removing tissue-oxidized lipids. However, whether ApoA-I mediates immune-suppressive or anti-inflammatory effects under normocholesterolemic conditions and the mechanisms involved remain unresolved. We transferred bone marrow from systemic lupus erythematosus (SLE)-prone Sle123 mice into normal, ApoA-I-knockout (ApoA-I(-/-)) and ApoA-I-transgenic (ApoA-I(tg)) mice. Increased ApoA-I in ApoA-I(tg) mice suppressed CD4(+) T and B cell activation without changing lymphocyte cholesterol levels or reducing major ApoA-I-binding oxidized fatty acids. Unexpectedly, oxidized fatty acid peroxisome proliferator-activated receptor γ ligands 13- and 9-hydroxyoctadecadienoic acid were increased in lymphocytes of autoimmune ApoA-I(tg) mice. ApoA-I reduced Th1 cells independently of changes in CD4(+)Foxp3(+) regulatory T cells or CD11c(+) dendritic cell activation and migration. Follicular helper T cells, germinal center B cells, and autoantibodies were also lower in ApoA-I(tg) mice. Transgenic ApoA-I also improved SLE-mediated glomerulonephritis. However, ApoA-I deficiency did not have the opposite effects on autoimmunity or glomerulonephritis, possibly as the result of compensatory increases in ApoE on high-density lipoprotein. We conclude that, although compensatory mechanisms prevent the proinflammatory effects of ApoA-I deficiency in normocholesterolemic mice, increasing ApoA-I can attenuate lymphocyte activation and autoimmunity in SLE independently of cholesterol transport, possibly through oxidized fatty acid peroxisome proliferator-activated receptor γ ligands, and it can reduce renal inflammation in glomerulonephritis.

  10. Human apolipoprotein B transgenic SHR/NDmcr-cp rats show exacerbated kidney dysfunction.

    PubMed

    Asahina, Makoto; Shimizu, Fumi; Ohta, Masayuki; Takeyama, Michiyasu; Tozawa, Ryuichi

    2015-01-01

    Nephropathy frequently co-occurs with metabolic syndrome in humans. Metabolic syndrome is a cluster of metabolic diseases including obesity, diabetes, hypertension, and dyslipidemia, and some previous studies revealed that dyslipidemia contributes to the progression of kidney dysfunction. To establish a new nephropathy model with metabolic syndrome, we produced human apolipoprotein B (apoB) transgenic (Tg.) SHR/NDmcr-cp (SHR-cp/cp) rats, in which dyslipidemia is exacerbated more than in an established metabolic syndrome model, SHR-cp/cp rats. Human apoB Tg. SHR-cp/cp rats showed obesity, hyperinsulinemia, hypertension, and severe hyperlipidemia. They also exhibited exacerbated early-onset proteinuria, accompanied by increased kidney injury and increased oxidative and inflammatory markers. Histological analyses revealed the characteristic features of human apoB Tg. SHR-cp/cp rats including prominent glomerulosclerosis with lipid accumulation. Our newly established human apoB Tg. SHR-cp/cp rat could be a useful model for the nephropathy in metabolic syndrome and for understanding the interaction between dyslipidemia and renal dysfunction in metabolic syndrome.

  11. Differential interaction of Apolipoprotein-E isoforms with insulin receptors modulates brain insulin signaling in mutant human amyloid precursor protein transgenic mice.

    PubMed

    Chan, Elizabeth S; Chen, Christopher; Cole, Gregory M; Wong, Boon-Seng

    2015-09-08

    It is unclear how human apolipoprotein E4 (ApoE4) increases the risk for Alzheimer's disease (AD). Although Aβ levels can lead to insulin signaling impairment, these experiments were done in the absence of human ApoE. To examine ApoE role, we crossed the human ApoE-targeted replacement mice with mutant human amyloid precursor protein (APP) mice. In 26 week old mice with lower Aβ levels, the expression and phosphorylation of insulin signaling proteins remained comparable among APP, ApoE3xAPP and ApoE4xAPP mouse brains. When the mice aged to 78 weeks, these proteins were markedly reduced in APP and ApoE4xAPP mouse brains. While Aβ can bind to insulin receptor, how ApoE isoforms modulate this interaction remains unknown. Here, we showed that ApoE3 had greater association with insulin receptor as compared to ApoE4, regardless of Aβ42 concentration. In contrast, ApoE4 bound more Aβ42 with increasing peptide levels. Using primary hippocampal neurons, we showed that ApoE3 and ApoE4 neurons are equally sensitive to physiological levels of insulin. However, in the presence of Aβ42, insulin failed to elicit a downstream response only in ApoE4 hippocampal neurons. Taken together, our data show that ApoE genotypes can modulate this Aβ-mediated insulin signaling impairment.

  12. Apolipoprotein A5: A newly identified gene impacting plasmatriglyceride levels in humans and mice

    SciTech Connect

    Pennacchio, Len A.; Rubin, Edward M.

    2002-09-15

    Apolipoprotein A5 (APOA5) is a newly described member of theapolipoprotein gene family whose initial discovery arose from comparativesequence analysis of the mammalian APOA1/C3/A4 gene cluster. Functionalstudies in mice indicated that alteration in the level of APOA5significantly impacted plasma triglyceride concentrations. Miceover-expressing human APOA5 displayed significantly reducedtriglycerides, while mice lacking apoA5 had a large increase in thislipid parameter. Studies in humans have also suggested an important rolefor APOA5 in determining plasma triglyceride concentrations. In theseexperiments, polymorphisms in the human gene were found to define severalcommon haplotypes that were associated with significant changes intriglyceride concentrations in multiple populations. Several separateclinical studies have provided consistent and strong support for theeffect with 24 percent of Caucasians, 35 percent of African-Americans and53 percent of Hispanics carrying APOA5 haplotypes associated withincreased plasma triglyceride levels. In summary, APOA5 represents anewly discovered gene involved in triglyceride metabolism in both humansand mice whose mechanism of action remains to be deciphered.

  13. Production of Cloned Miniature Pigs Expressing High Levels of Human Apolipoprotein(a) in Plasma.

    PubMed

    Ozawa, Masayuki; Himaki, Takehiro; Ookutsu, Shoji; Mizobe, Yamato; Ogawa, Junki; Miyoshi, Kazuchika; Yabuki, Akira; Fan, Jianglin; Yoshida, Mitsutoshi

    2015-01-01

    High lipoprotein(a) [Lp(a)] levels are a major risk factor for the development of atherosclerosis. However, because apolipoprotein(a) [apo(a)], the unique component of Lp(a), is found only in primates and humans, the study of human Lp(a) has been hampered due to the lack of appropriate animal models. Using somatic cell nuclear transfer (SCNT) techniques, we produced transgenic miniature pigs expressing human apo(a) in the plasma. First, we placed the hemagglutinin (HA)-tagged cDNA of human apo(a) under the control of the β-actin promoter and cytomegalovirus enhancer, and then introduced this construct into kidney epithelial cells. Immunostaining of cells with anti-HA antibody allowed identification of cells stably expressing apo(a); one of the positive clones was used to provide donor cells for SCNT, yielding blastocysts that expressed apo(a). Immunohistochemical analysis of tissue sections and RT-PCR analysis of total RNA from organs of cloned piglet revealed that apo(a) is expressed in various tissues/organs including heart, liver, kidney, and intestine. More importantly, a transgenic line exhibited a high level (>400 mg/dL) of Lp(a) in plasma, and the transgenic apo(a) gene was transmitted to the offspring. Thus, we generated a human apo(a)-transgenic miniature pig that can be used as a model system to study advanced atherosclerosis related to human disease. The anatomical and physiological similarities between the swine and human cardiovascular systems will make this pig model a valuable source of information on the role of apo(a) in the formation of atherosclerosis, as well as the mechanisms underlying vascular health and disease. PMID:26147378

  14. Production of Cloned Miniature Pigs Expressing High Levels of Human Apolipoprotein(a) in Plasma

    PubMed Central

    Ozawa, Masayuki; Himaki, Takehiro; Ookutsu, Shoji; Mizobe, Yamato; Ogawa, Junki; Miyoshi, Kazuchika; Yabuki, Akira; Fan, Jianglin; Yoshida, Mitsutoshi

    2015-01-01

    High lipoprotein(a) [Lp(a)] levels are a major risk factor for the development of atherosclerosis. However, because apolipoprotein(a) [apo(a)], the unique component of Lp(a), is found only in primates and humans, the study of human Lp(a) has been hampered due to the lack of appropriate animal models. Using somatic cell nuclear transfer (SCNT) techniques, we produced transgenic miniature pigs expressing human apo(a) in the plasma. First, we placed the hemagglutinin (HA)-tagged cDNA of human apo(a) under the control of the β-actin promoter and cytomegalovirus enhancer, and then introduced this construct into kidney epithelial cells. Immunostaining of cells with anti-HA antibody allowed identification of cells stably expressing apo(a); one of the positive clones was used to provide donor cells for SCNT, yielding blastocysts that expressed apo(a). Immunohistochemical analysis of tissue sections and RT-PCR analysis of total RNA from organs of cloned piglet revealed that apo(a) is expressed in various tissues/organs including heart, liver, kidney, and intestine. More importantly, a transgenic line exhibited a high level (>400 mg/dL) of Lp(a) in plasma, and the transgenic apo(a) gene was transmitted to the offspring. Thus, we generated a human apo(a)–transgenic miniature pig that can be used as a model system to study advanced atherosclerosis related to human disease. The anatomical and physiological similarities between the swine and human cardiovascular systems will make this pig model a valuable source of information on the role of apo(a) in the formation of atherosclerosis, as well as the mechanisms underlying vascular health and disease. PMID:26147378

  15. Apolipoprotein D synthesis progressively increases in frontal cortex during human lifespan.

    PubMed

    Navarro, Ana; del Valle, Eva; Juárez, Amalia; Martinez, Eva; Ordóñez, Cristina; Astudillo, Aurora; Tolivia, Jorge

    2010-03-01

    Apolipoprotein D (apo D) is a lipocalin present in the nervous system that may be related to processes of reinnervation, regeneration and neuronal cell protection. On the other hand, apo D expression has been correlated, in some brain regions, with normal ageing and neurodegenerative diseases. To elucidate the regional and cellular expression of apo Din normal human brain during ageing, we performed a detailed and extensive study in samples of post-mortem human cerebral cortices. To achieve this study, slot-blot techniques, for protein and mRNA,as well as immunohistochemistry and hybridohistochemistry methods, were used. A positive correlation for apo D expression with ageing was found;furthermore, mRNA levels, as well as the protein ones, were higher in the white than in the grey matter. Immunohistochemistry and non-isotopic in situ hybridization showed that apo D is synthesised in both neurons and glial cells. Apo D expression is notorious in oligodendrocytes, but with ageing, the number of neurons that synthesise apo D is increased.Our results indicate that apo D could play a fundamental role in central nervous system ageing and in the reduction of products derived from lipid peroxidation. The increment in the expression of apo D with ageing can be included in a global mechanism of cellular protection to prevent the deleterious effects caused by ageing.

  16. Macrophage-specific expression of human apolipoprotein E reduces atherosclerosis in hypercholesterolemic apolipoprotein E-null mice.

    PubMed Central

    Bellosta, S; Mahley, R W; Sanan, D A; Murata, J; Newland, D L; Taylor, J M; Pitas, R E

    1995-01-01

    apoE deficiency causes hyperlipidemia and premature atherosclerosis. To determine if macrophage-specific expression of apoE would decrease the extent of atherosclerosis, we expressed human apoE in macrophages of apoE-null mice (apoE-/-) and assessed the effect on lipid accumulation in cells of the arterial wall. Macrophage-specific expression of human apoE in normal mice was obtained by use of the visna virus LTR. These animals were bred with apoE-/- mice to produce animals hemizygous for expression of human apoE in macrophages in the absence of murine apoE (apoE-/-,hTgE+/0). Low levels of human apoE mRNA were present in liver and spleen and high levels in lung and peritoneal macrophages. Human apoE was secreted by peritoneal macrophages and was detected in Kupffer cells of the liver. Human apoE in the plasma of apoE-/-,hTgE+/0 mice (n = 30) was inversely correlated (P < 0.005) with the plasma cholesterol concentration. After 15 wk on a normal chow diet, atherosclerosis was assessed in apoE-/-,hTgE+/0 animals and in apoE-/-,hTgE0/0 littermates matched for plasma cholesterol level (approximately 450 mg/dl) and lipoprotein profile. There was significantly less atherosclerosis in both the aortic sinus and in the proximal aorta (P < 0.0001) in the animals expressing the human apoE transgene. In apo-E-/-,hTgE+/0 animals, which had detectable atherosclerotic lesions, human apoE was detected in the secretory apparatus of macrophage-derived foam cells in the arterial wall. The data demonstrate that expression of apoE by macrophages is antiatherogenic even in the presence of high levels of atherogenic lipoproteins. The data suggest that apoE prevents atherosclerosis by promoting cholesterol efflux from cells of the arterial wall. Images PMID:7593602

  17. The insertion of human apolipoprotein H into phospholipid membranes: a monolayer study.

    PubMed Central

    Wang, S X; Cai, G P; Sui, S F

    1998-01-01

    Apolipoprotein H (ApoH) is a plasma glycoprotein isolated from human serum. The interactions of ApoH with lipid membrane were reported to be essential for its physiological and pathogenic roles. In this paper we studied the ability of ApoH to insert into phospholipid membranes using the monolayer approach. The results show that ApoH is surface active and can insert into the lipid monolayers. The insertion ability of ApoH is stronger when a higher content of negatively charged lipids is present in the membrane. The acidic-pH and low-ionic-strength conditions will also enhance ApoH insertion, but these factors may not have much influence on the final insertion ability of ApoH, suggesting that, in the mechanism of ApoH insertion, not only electrostatic forces, but also hydrophobic interactions, are evidently involved. Modification by heat inactivation and reduction/alkylation does not change the critical insertion pressure (pic) of ApoH, suggesting a stable domain, maybe a linear sequence motif, but not the native three-dimensional structure of ApoH, is responsible for its insertion. The extent to which insertion of ApoH into phospholipid membranes may facilitate the 'immune cleaning' of plasma liposomes is discussed. PMID:9761718

  18. The insertion of human apolipoprotein H into phospholipid membranes: a monolayer study.

    PubMed

    Wang, S X; Cai, G P; Sui, S F

    1998-10-15

    Apolipoprotein H (ApoH) is a plasma glycoprotein isolated from human serum. The interactions of ApoH with lipid membrane were reported to be essential for its physiological and pathogenic roles. In this paper we studied the ability of ApoH to insert into phospholipid membranes using the monolayer approach. The results show that ApoH is surface active and can insert into the lipid monolayers. The insertion ability of ApoH is stronger when a higher content of negatively charged lipids is present in the membrane. The acidic-pH and low-ionic-strength conditions will also enhance ApoH insertion, but these factors may not have much influence on the final insertion ability of ApoH, suggesting that, in the mechanism of ApoH insertion, not only electrostatic forces, but also hydrophobic interactions, are evidently involved. Modification by heat inactivation and reduction/alkylation does not change the critical insertion pressure (pic) of ApoH, suggesting a stable domain, maybe a linear sequence motif, but not the native three-dimensional structure of ApoH, is responsible for its insertion. The extent to which insertion of ApoH into phospholipid membranes may facilitate the 'immune cleaning' of plasma liposomes is discussed.

  19. A zone immunoelectrophoresis assay method for quantification of apolipoprotein D in human cerebrospinal fluid.

    PubMed

    Holmquist, L; Fredrikson, S; Vesterberg, O

    1996-10-15

    A zone immunoelectrophoresis assay (ZIA) has been developed for the quantification of apolipoprotein D (apo D) in human unconcentrated cerebrospinal fluid (CSF). The apo D concentrations of samples of the serum, plasma and CSF were directly proportional to the migration distances of the corresponding zones of immunoprecipitates developed during electrophoresis in glass capillaries filled with antibody-containing agarose gel. A linear standard curve, between about 1 and 12 mg of apo D/1 was obtained using a commercial serum preparation. Seronorm, as apo D standard. The coefficients of variation of the ZIA were below 8% (n = 5 x 6) and 10% (n = 8) for within-run and between-run reproducibility, respectively. Quantification experiments with disulfide-reducing agent, mixtures of CSF and urine as well as frozen and stored CSF samples indicated parallelism between the precipitate-forming immunologic reactions of apo D in different sample matrices when performed with ZIA. Application of this method to quantify apo D of CSF and plasma samples from 51 normal healthy men aged 16-72 years yielded means +/- SD of 5.3 +/- 1.5 mg/l and 128.4 +/- 22.7 mg/l, respectively. No correlation was found between the CSF and plasma apo D concentrations.

  20. Comparative surface antimicrobial properties of synthetic biocides and novel human apolipoprotein E derived antimicrobial peptides.

    PubMed

    Forbes, Sarah; McBain, Andrew J; Felton-Smith, Susan; Jowitt, Thomas A; Birchenough, Holly L; Dobson, Curtis B

    2013-07-01

    Medical device infection remains a major clinical concern. Biocidal compounds have been incorporated into medical device materials ideally to inhibit bacterial colonisation whilst exhibiting relatively low cytotoxicity. We compared the antibacterial activity, anti-biofilm efficacy and cytotoxicity of a novel peptide derivative of human apolipoprotein E (apoEdpL-W) to that of commonly used biocides, before and after coating onto a range of standard polymers. Since the antimicrobial function of most biocides frequently involves associations with cellular membranes, we have also studied the detailed interactions of the test antimicrobials with phospholipid bilayers, using the quartz crystal microbalance device combined with dual-polarisation interferometry. ApoEdpL-W displayed broad-spectrum antibacterial activity and marked efficacy against nascent Staphylococcus aureus biofilms. Compounds showed better antimicrobial activity when combined with hydrogel materials than with non-porous materials. The membrane interactions of apoEdpL-W were most similar to that of PHMB, with both agents appearing to readily bind and insert into lipid bilayers, possibly forming pores. However apoEdpL-W showed lower cytotoxicity than PHMB, its efficacy was less affected by the presence of serum, and it demonstrated the highest level of biocompatibility of all the biocides, as indicated by our measurement of its antimicrobial biocompatibility index. This work shows the potential of apoEdpL-W as an effective antiseptic coating agent. PMID:23623325

  1. Expression of the human apolipoprotein E gene suppresses steroidogenesis in mouse Y1 adrenal cells

    SciTech Connect

    Reyland, M.E.; Forgez, P.; Prack, M.M.; Williams, D.L. ); Gwynne, J.T. )

    1991-03-15

    The lipid transport protein, apolipoprotein E (apoE), is expressed in many peripheral tissues in vivo including the adrenal gland and testes. To investigate the role of apoE in adrenal cholesterol homeostasis, the authors have expressed a human apoE genomic clone in the Y1 mouse adrenocortical cell line. Y1 cells do not express endogenous apoE mRNA or protein. Expression of apoE in Y1 cells resulted in a dramatic decrease in basal steroidogenesis; secretion of fluorogenic steroid was reduced 7- to {gt}100-fold relative to Y1 parent cells. Addition of 5-cholesten-3{beta},25-idol failed to overcome the suppression of steroidogenesis in these cells. Cholesterol esterification under basal conditions, as measured by the production of cholesteryl ({sup 14}C)oleate, was similar in the Y1 parent and the apoE-transfected cell lines. Upon incubation with adrenocorticotropin or dibutyryl cAMP, production of cholesteryl ({sup 14}C)oleate decreased 5-fold in the Y1 parent cells but was unchanged in the apoE-transfected cell lines. These results suggest that apoE may be an important modulator of cholesterol utilization and steroidogenesis in adrenal cells.

  2. Modulation of Apolipoprotein D levels in human pregnancy and association with gestational weight gain

    PubMed Central

    2009-01-01

    Background Apolipoprotein D (ApoD) is a lipocalin involved in several processes including lipid transport, but its modulation during human pregnancy was never examined. Methods We investigated the changes in the levels of ApoD in the plasma of pregnant women at the two first trimesters of gestation and at delivery as well as in the placenta and in venous cord blood. These changes were studied in 151 women classified into 9 groups in relation to their prepregnancy body mass index (BMI) and gestational weight gain (GWG). Results Plasma ApoD levels decrease significantly during normal uncomplicated pregnancy. ApoD is further decreased in women with excessive GWG and their newborns. In these women, the ApoD concentration was tightly associated with the lipid parameters. However, the similar ApoD levels in low cholesterol (LC) and high cholesterol (HC) women suggest that the plasma ApoD variation is not cholesterol dependant. A tight regulation of both placental ApoD transcription and protein content is most probably at the basis of the low circulating ApoD concentrations in women with excessive GWG. After delivery, the plasma ApoD concentrations depended on whether the mother was breast-feeding or not, lactation favoring a faster return to baseline values. Conclusion It is speculated that the decrease in plasma ApoD concentration during pregnancy is an adaptive response aimed at maintaining fetal lipid homeostasis. The exact mechanism of this adaptation is not known. PMID:19723339

  3. Two independent apolipoprotein A5 haplotypes influence human plasma triglyceride levels.

    PubMed

    Pennacchio, Len A; Olivier, Michael; Hubacek, Jaroslav A; Krauss, Ronald M; Rubin, Edward M; Cohen, Jonathan C

    2002-11-15

    The recently identified apolipoprotein A5 gene (APOA5) has been shown to play an important role in determining plasma triglyceride concentrations in humans and mice. We previously identified an APOA5 haplotype (designated APOA5*2) that is present in approximately 16% of Caucasians and is associated with increased plasma triglyceride concentrations. In this report we describe another APOA5 haplotype (APOA5*3) containing the rare allele of the single nucleotide polymorphism c.56C>G that changes serine to tryptophan at codon 19 and is independently associated with high plasma triglyceride levels in three different populations. In a sample of 264 Caucasian men and women with plasma triglyceride concentrations above the 90th percentile or below the 10th percentile, the APOA5*3 haplotype was more than three-fold more common in the group with high plasma triglyceride levels. In a second independently ascertained sample of Caucasian men and women (n=419) who were studied while consuming their self-selected diets as well as after high-carbohydrate diets and high-fat diets, the APOA5*3 haplotype was associated with increased plasma triglyceride levels on all three dietary regimens. In a third population comprising 2660 randomly selected individuals, the APOA5*3 haplotype was found in 12% of Caucasians, 14% of African-Americans and 28% of Hispanics and was associated with increased plasma triglyceride levels in both men and women in each ethnic group. These findings establish that the APOA5 locus contributes significantly to inter-individual variation in plasma triglyceride levels in humans. Together, the APOA5*2 and APOA5*3 haplotypes are found in 25-50% of African-Americans, Hispanics and Caucasians and support the contribution of common human variation to quantitative phenotypes in the general population.

  4. Two independent apolipoprotein a5 Haplotypes influence human plasma triglyceride levels

    SciTech Connect

    Pennacchio, Len A.; Olivier, Michael; Hubacek, Jaroslav A.; Krauss, Ronald M.; Rubin, Edward M.; Cohen, Jonathan C.

    2002-09-16

    The recently identified apolipoprotein A5 gene (APOA5) has been shown to play an important role in determining plasma triglyceride concentrations in humans and mice. We previously identified an APOA5 haplotype (designated APOA5*2) that is present in {approx}16 percent of Caucasians and is associated with increased plasma triglyceride concentrations. In this report we describe another APOA5 haplotype (APOA5*3) containing the rare allele of the single nucleotide polymorphism c.56C>G that changes serine to tryptophan at codon 19 and is independently associated with high plasma triglyceride levels in three different populations. In a sample of 264 Caucasian men and women with plasma triglyceride concentrations above the 90th percentile or below the 10th percentile, the APOA5*3 haplotype was more than three-fold more common in the group with high plasma triglyceride levels. In a second independently ascertained sample of Caucasian men and women (n 1/4 419) who were studied while consuming their self-selected diets as well as after high-carbohydrate diets and high-fat diets, the APOA5*3 haplotype was associated with increased plasma triglyceride levels on all three dietary regimens. In a third population comprising 2660 randomly selected individuals, the APOA5*3 haplotype was found in 12 percent of Caucasians, 14 percent of African-Americans and 28 percent of Hispanics and was associated with increased plasma triglyceride levels in both men and women in each ethnic group. These findings establish that the APOA5 locus contributes significantly to inter-individual variation in plasma triglyceride levels in humans. Together, the APOA5*2 and APOA5*3 haplotypes are found in 25 50 percent of African-Americans, Hispanics and Caucasians and support the contribution of common human variation to quantitative phenotypes in the general population.

  5. Hyperlipidemia and cutaneous abnormalities in transgenic mice overexpressing human apolipoprotein C1.

    PubMed

    Jong, M C; Gijbels, M J; Dahlmans, V E; Gorp, P J; Koopman, S J; Ponec, M; Hofker, M H; Havekes, L M

    1998-01-01

    Transgenic mice were generated with different levels of human apolipoprotein C1 (APOC1) expression in liver and skin. At 2 mo of age, serum levels of cholesterol, triglycerides (TG), and FFA were strongly elevated in APOC1 transgenic mice compared with wild-type mice. These elevated levels of serum cholesterol and TG were due mainly to an accumulation of VLDL particles in the circulation. In addition to hyperlipidemia, APOC1 transgenic mice developed dry and scaly skin with loss of hair, dependent on the amount of APOC1 expression in the skin. Since these skin abnormalities appeared in two independent founder lines, a mutation related to the specific insertion site of the human APOC1 gene as the cause for the phenotype can be excluded. Histopathological analysis of high expressor APOC1 transgenic mice revealed a disorder of the skin consisting of epidermal hyperplasia and hyperkeratosis, and atrophic sebaceous glands lacking sebum. In line with these results, epidermal lipid analysis showed that the relative amounts of the sebum components TG and wax diesters in the epidermis of high expressor APOC1 transgenic mice were reduced by 60 and 45%, respectively. In addition to atrophic sebaceous glands, the meibomian glands were also found to be severely atrophic in APOC1 transgenic mice. High expressor APOC1 transgenic mice also exhibited diminished abdominal adipose tissue stores (a 60% decrease compared with wild-type mice) and a complete deficiency of subcutaneous fat. These results indicate that, in addition to the previously reported inhibitory role of apoC1 on hepatic remnant uptake, overexpression of apoC1 affects lipid synthesis in the sebaceous gland and/or epidermis as well as adipose tissue formation. These APOC1 transgenic mice may serve as an interesting in vivo model for the investigation of lipid homeostasis in the skin.

  6. Complex effects of inhibiting hepatic apolipoprotein B100 synthesis in humans

    PubMed Central

    Reyes-Soffer, Gissette; Moon, Byoung; Hernandez-Ono, Antonio; Dionizovik-Dimanovski, Marija; Jimenez, Jhonsua; Obunike, Joseph; Thomas, Tiffany; Ngai, Colleen; Fontanez, Nelson; Donovan, Daniel S.; Karmally, Wahida; Holleran, Stephen; Ramakrishnan, Rajasekhar; Mittleman, Robert S.; Ginsberg, Henry N.

    2016-01-01

    Mipomersen is a 20mer antisense oligonucleotide (ASO) that inhibits apolipoprotein B (apoB) synthesis; its low-density lipoprotein (LDL)–lowering effects should therefore result from reduced secretion of very-low-density lipoprotein (VLDL). We enrolled 17 healthy volunteers who received placebo injections weekly for 3 weeks followed by mipomersen weekly for 7 to 9 weeks. Stable isotopes were used after each treatment to determine fractional catabolic rates and production rates of apoB in VLDL, IDL (intermediate-density lipoprotein), and LDL, and of triglycerides in VLDL. Mipomersen significantly reduced apoB in VLDL, IDL, and LDL, which was associated with increases in fractional catabolic rates of VLDL and LDL apoB and reductions in production rates of IDL and LDL apoB. Unexpectedly, the production rates of VLDL apoB and VLDL triglycerides were unaffected. Small interfering RNA–mediated knockdown of apoB expression in human liver cells demonstrated preservation of apoB secretion across a range of apoB synthesis. Titrated ASO knockdown of apoB mRNA in chow-fed mice preserved both apoB and triglyceride secretion. In contrast, titrated ASO knockdown of apoB mRNA in high-fat–fed mice resulted in stepwise reductions in both apoB and triglyceride secretion. Mipomersen lowered all apoB lipoproteins without reducing the production rate of either VLDL apoB or triglyceride. Our human data are consistent with longstanding models of posttranscriptional and posttranslational regulation of apoB secretion and are supported by in vitro and in vivo experiments. Targeting apoB synthesis may lower levels of apoB lipoproteins without necessarily reducing VLDL secretion, thereby lowering the risk of steatosis associated with this therapeutic strategy. PMID:26819195

  7. Human-centered automation and AI - Ideas, insights, and issues from the Intelligent Cockpit Aids research effort

    NASA Technical Reports Server (NTRS)

    Abbott, Kathy H.; Schutte, Paul C.

    1989-01-01

    A development status evaluation is presented for the NASA-Langley Intelligent Cockpit Aids research program, which encompasses AI, human/machine interfaces, and conventional automation. Attention is being given to decision-aiding concepts for human-centered automation, with emphasis on inflight subsystem fault management, inflight mission replanning, and communications management. The cockpit envisioned is for advanced commercial transport aircraft.

  8. Fluorescence study of domain structure and lipid interaction of human apolipoproteins E3 and E4.

    PubMed

    Mizuguchi, Chiharu; Hata, Mami; Dhanasekaran, Padmaja; Nickel, Margaret; Okuhira, Keiichiro; Phillips, Michael C; Lund-Katz, Sissel; Saito, Hiroyuki

    2014-12-01

    Human apolipoprotein E (apoE) isoforms exhibit different conformational stabilities and lipid-binding properties that give rise to altered cholesterol metabolism among the isoforms. Using Trp-substituted mutations and site- directed fluorescence labeling, we made a comprehensive comparison of the conformational organization of the N- and C-terminal domains and lipid interactions between the apoE3 and apoE4 isoforms. Trp fluorescence measurements for selectively Trp-substituted variants of apoE isoforms demonstrated that apoE4 adopts less stable conformations in both the N- and C-terminal domains compared to apoE3. Consistent with this, the conformational reorganization of the N-terminal helix bundle occurs at lower guanidine hydrochloride concentration in apoE4 than in apoE3 as monitored by fluorescence resonance energy transfer (FRET) from Trp residues to acrylodan attached at the N-terminal helix. Upon binding of apoE3 and apoE4 variants to egg phosphatidylcholine small unilamellar vesicles, similar changes in Trp fluorescence or FRET efficiency were observed for the isoforms, indi- cating that the opening of the N-terminal helix bundle occurs similarly in apoE3 and apoE4. Introduction of mutations into the C-terminal domain of the apoE isoforms to prevent self-association and maintain the monomeric state resulted in great increase in the rate of binding of the C-terminal helices to a lipid surface. Overall, our results demonstrate that the different conformational organizations of the N- and C-terminal domains have a minor effect on the steady-state lipid-binding behavior of apoE3 and apoE4: rather, self-association property is a critical determinant in the kinetics of lipid binding through the C-terminal helices of apoE isoforms.

  9. Metabolism of Apolipoprotein A-II Containing Triglyceride Rich ApoB Lipoproteins in Humans

    PubMed Central

    Desai, Nirav K.; Ooi, Esther M.; Mitchell, Paul D.; Furtado, Jeremy; Sacks, Frank M.

    2015-01-01

    Objective To characterize human triglyceride-rich lipoproteins (TRL) with and without apoA-II and to study their metabolism in vivo. Methods Plasma from 11 participants on a controlled diet given a bolus infusion of [D5]L-phenylalanine to label apoB was combined into four pools and applied to anti-apoA-II immunoaffinity columns. Fractions with and without apoA-II were separated into VLDL and IDL by ultracentrifugation; lipids and apolipoproteins were measured. For kinetic measurements, apoB was isolated and hydrolyzed to the constituent amino acids. Tracer enrichment was measured by GCMS. Metabolic rates were determined by SAAM-II. Results VLDL and IDL with apoA-II comprised 7% and 9% of total VLDL and IDL apoB respectively. VLDL with apoA-II was enriched in apoC-III, apoE, and cholesterol compared to VLDL without apoA-II. Mean apoB FCR of VLDL with apoA-II was significantly lower than for VLDL without apoA-II (2.80±0.96 pools/day v.s. 5.09±1.69 pools/day, P=0.009). A higher percentage of VLDL with apoA-II was converted to IDL than was cleared from circulation, compared to VLDL without apoA-II (96±8% vs. 45±22%; P=0.007). The rate constants for conversion of VLDL to IDL were similar for VLDL with and without apoA-II. Thus, a very low rate constant for clearance accounted for the lower FCR of VLDL with apoA-II. Conclusion VLDL with apoA-II represents a small pool of VLDL particles that has a slow FCR and is predominantly converted to IDL rather than cleared from the circulation. PMID:26071654

  10. Worldwide allele frequencies of the human apolipoprotein E gene: climate, local adaptations, and evolutionary history.

    PubMed

    Eisenberg, Dan T A; Kuzawa, Christopher W; Hayes, M Geoffrey

    2010-09-01

    The epsilon4 allele of the apolipoprotein E (APOE) gene is associated with increased cholesterol levels and heart disease. Population allele frequencies of APOE have previously been shown to vary, with epsilon4 frequencies generally increasing with latitude. We hypothesize that this trend resulted from natural selection protecting against low-cholesterol levels. In high-latitude cold environments and low-latitude hot environments, metabolic rate is elevated, which could require higher cholesterol levels. To explore this hypothesis, we compiled APOE allele frequencies, latitude, temperature, and elevation from populations around the world. epsilon4 allele frequencies show a curvilinear relationship with absolute latitude, with lowest frequencies found in the mid-latitudes where temperatures generally require less expenditure on cooling/thermogenesis. Controlling for population structure in a subset of populations did not appreciably change this pattern of association, consistent with selection pressures that vary by latitude shaping epsilon4 allele frequencies. Temperature records also predict APOE frequency in a curvilinear fashion, with lowest epsilon4 frequencies at moderate temperatures. The model fit between historical temperatures and epsilon4 is less than between latitude and epsilon4, but strengthened after correcting for estimated temperature differences during the Paleolithic. Contrary to our hypothesis, we find that elevation did not improve predictive power, and an integrated measure of the cholesterol effect of multiple APOE alleles was less related to latitude than was epsilon4 alone. Our results lend mixed support for a link between past temperature and human APOE allele distribution and point to the need to develop better models of past climate in future analyses.

  11. AI techniques for optimizing multi-objective reservoir operation upon human and riverine ecosystem demands

    NASA Astrophysics Data System (ADS)

    Tsai, Wen-Ping; Chang, Fi-John; Chang, Li-Chiu; Herricks, Edwin E.

    2015-11-01

    Flow regime is the key driver of the riverine ecology. This study proposes a novel hybrid methodology based on artificial intelligence (AI) techniques for quantifying riverine ecosystems requirements and delivering suitable flow regimes that sustain river and floodplain ecology through optimizing reservoir operation. This approach addresses issues to better fit riverine ecosystem requirements with existing human demands. We first explored and characterized the relationship between flow regimes and fish communities through a hybrid artificial neural network (ANN). Then the non-dominated sorting genetic algorithm II (NSGA-II) was established for river flow management over the Shihmen Reservoir in northern Taiwan. The ecosystem requirement took the form of maximizing fish diversity, which could be estimated by the hybrid ANN. The human requirement was to provide a higher satisfaction degree of water supply. The results demonstrated that the proposed methodology could offer a number of diversified alternative strategies for reservoir operation and improve reservoir operational strategies producing downstream flows that could meet both human and ecosystem needs. Applications that make this methodology attractive to water resources managers benefit from the wide spread of Pareto-front (optimal) solutions allowing decision makers to easily determine the best compromise through the trade-off between reservoir operational strategies for human and ecosystem needs.

  12. Plasma clearance of human low-density lipoprotein in human apolipoprotein B transgenic mice is related to particle diameter.

    PubMed

    Berneis, Kaspar; Shames, David M; Blanche, Patricia J; La Belle, Michael; Rizzo, Manfredi; Krauss, Ronald M

    2004-04-01

    To test for intrinsic differences in metabolic properties of low-density lipoprotein (LDL) as a function of particle size, we examined the kinetic behavior of 6 human LDL fractions ranging in size from 251 to 265 A injected intravenously into human apolipoprotein (apo) B transgenic mice. A multicompartmental model was formulated and fitted to the data by standard nonlinear regression using the Simulation, Analysis and Modeling (SAAM II) program. Smaller sized LDL particles (251 to 257 A) demonstrated a significantly slower fractional catabolic rate (FCR) (0.050 +/- 0.045 h(-1)) compared with particles of larger size (262 to 265 A) (0.134 +/- -0.015 h(-1), P <.03), and there was a significant correlation between FCR and the peak LDL diameter of the injected fractions (R(2) =.71, P <.034). The sum of the equilibration parameters, k(2,1) and k(1,2), for smaller LDL (0.255 h(-1) and 0.105 h(-1), respectively) was significantly smaller than that for larger LDL (0.277 h(-1) and 0.248 h(-1), respectively; P <.01), indicative of slower intravascular-extravascular exchange for smaller LDL. Therefore in this mouse model, smaller LDL particles are cleared more slowly from plasma than larger LDL and are exchanged more slowly with the extravascular space. This might be due to compositional or structural features of smaller LDL that lead to retarded clearance.

  13. Lipid binding ability of human apolipoprotein E N-terminal domain isoforms: correlation with protein stability?

    PubMed

    Weers, Paul M M; Narayanaswami, Vasanthy; Choy, Nicole; Luty, Robert; Hicks, Les; Kay, Cyril M; Ryan, Robert O

    2003-01-01

    Human apolipoprotein (apo) E exists as one of three major isoforms, E2, E3 or E4. Individuals carrying the epsilon 4 allele have an increased risk of heart disease and premature onset of Alzheimer's disease. To investigate the molecular basis for this phenomenon, the N-terminal domain of apoE3, apoE2 and apoE4 were expressed in bacteria, isolated and employed in lipid binding and stability studies. Far UV circular dichroism spectroscopy in buffer at pH 7 revealed a similar amount of alpha-helix secondary structure for the three isoforms. By contrast, differences were noted in apoE-NT isoform-specific transformation of bilayer vesicles of dimyristoylphosphatidylglycerol (DMPG) into discoidal complexes. ApoE4-NT induced transformation was most rapid, followed by apoE3-NT and apoE2-NT. To determine if differences in the rate of apoE-NT induced DMPG vesicle transformation is due to isoform-specific differences in helix bundle stability, guanidine HCl denaturation studies were conducted. The results revealed that apoE2-NT was the most stable, followed by apoE3-NT and apoE4-NT, establishing an inverse correlation between helix bundle stability and DMPG vesicle transformation rate at pH 7. When the zwitterionic dimyristoylphosphatidylcholine (DMPC) was employed as the model lipid surface, interaction of apoE-NT isoforms with the lipid substrate was slow. However, upon lowering the pH from 7 to 3, a dramatic increase in the rate of DMPC vesicle transformation rate was observed for each isoform. To evaluate if the increased DMPC vesicle transformation rates observed at low pH is due to pH-dependent alterations in helix bundle stability, guanidine HCl denaturation studies were performed. ApoE2-NT and apoE3-NT displayed increased resistance to denaturation as a function of decreasing pH, while apoE4-NT showed no change in stability. Studies with the fluorescent probe, 8-anilino-1-naphthalene sulfonic acid, indicated an increase in apoE hydrophobic surface exposure upon

  14. Inter-molecular coiled-coil formation in human apolipoprotein E C-terminal domain.

    PubMed

    Choy, Nicole; Raussens, Vincent; Narayanaswami, Vasanthy

    2003-11-28

    Human apolipoprotein E (apoE) is composed of an N-terminal (NT) domain (residues 1-191) that bears low-density lipoprotein receptor-binding sites, and a C-terminal (CT) domain (residues 210-299), which houses lipoprotein binding and apoE self-association sites. The NT domain is comprised of a four-helix bundle, while the structural organization of the CT domain is not known. Secondary structural algorithms predict that the apoE CT domain adopts an amphipathic alpha-helical conformation. On the basis of further sequence predictions, we identified a segment (residues 218-266) in the apoE CT domain that bears a high propensity to form a coiled-coil helix, which coincides with the putative lipoprotein-binding surface. An apoE construct bearing residues 201-299 that encompasses the entire CT domain was designed, expressed in Escherichia coli and purified by affinity chromatography. Circular dichroism (CD) spectroscopy of the apoE CT domain reveals spectra characteristic of coiled-coil helices, with the ratio of molar ellipticities at 222 nm and 208 nm ([theta](222)/[theta](208)) of 1.03. Trifluoroethanol (TFE) stabilized the secondary structure of the apoE CT domain and disrupted coiled-coil helix formation as determined by CD and tryptophan fluorescence analysis. Analytical ultracentrifugation and lysine-specific cross-linking analysis of the apoE CT domain revealed predominant formation of dimeric and tetrameric species in aqueous buffers, and monomeric forms in 50% TFE. Guanidine hydrochloride-induced denaturation studies reveal that, at low concentrations of denaturant, the apoE CT domain maintains the [theta](222)/[theta](208) ratio at approximately 1.0 and elicits an altered tertiary environment with a shift in oligomeric state towards a dimer, indicative of the role of coiled-coil helix formation in inter molecular interactions. Further, coiled-coil formation is disrupted by protonation below pH 6.0, with a corresponding decrease in Trp fluorescence emission

  15. Antiangiogenic Therapy with Human Apolipoprotein(a) Kringle V and Paclitaxel in a Human Ovarian Cancer Mouse Model12

    PubMed Central

    Yu, Hyun-Kyung; Lee, Ho-Jeong; Yun, Seok-Joong; Lee, Sun-Joo; Langley, Robert R.; Yoon, Yeup; Yi, Lee S.H.; Bae, Duk-Soo; Kim, Jang-Seong; Kim, Sun Jin

    2014-01-01

    INTRODUCTION: The present study compared the effect of combination therapy using human apolipoprotein(a) kringle V (rhLK8) to conventional chemotherapy with paclitaxel for human ovarian carcinoma producing high or low levels of vascular endothelial growth factor (VEGF). MATERIALS AND METHODS: Human ovarian carcinoma cells producing high (SKOV3ip1) or low (HeyA8) levels of VEGF were implanted into the peritoneal cavity of female nude mice. Seven days later, mice were randomized into four groups: control (vehicle), paclitaxel [5 mg/kg, weekly intraperitoneal (i.p.) injection], rhLK8 (50 mg/kg, daily i.p. injection), or the combination of paclitaxel and rhLK8. Mice were treated for 4 weeks and examined by necropsy. RESULTS: In mice implanted with SKOV3ip1 cells, rhLK8 treatment had no significant effect on tumor incidence or the volume of ascites but induced a significant decrease in tumor weight compared with control mice. Paclitaxel significantly reduced tumor weight and ascites volume, and combination treatment with paclitaxel and rhLK8 had an additive therapeutic effect. Similarly, in HeyA8 mice, the effect of combination treatment on tumor weight and tumor incidence was statistically significantly greater than that of paclitaxel or rhLK8 alone. Immunohistochemical analysis showed a significant decrease in microvessel density and a marked increase of apoptosis in tumor and tumor-associated endothelial cells in response to combination treatment with paclitaxel and rhLK8. CONCLUSION: Collectively, these results suggest that antiangiogenic therapy with rhLK8 in combination with taxane-based conventional chemotherapy could be effective for the treatment of ovarian carcinomas, regardless of VEGF status. PMID:25180060

  16. Human ApoD, an apolipoprotein up-regulated in neurodegenerative diseases, extends lifespan and increases stress resistance in Drosophila

    PubMed Central

    Muffat, Julien; Walker, David W.; Benzer, Seymour

    2008-01-01

    Apolipoprotein D (ApoD) expression increases in several neurological disorders and in spinal cord injury. We provide a report of a physiological role for human ApoD (hApoD): Flies overexpressing hApoD are long-lived and protected against stress conditions associated with aging and neurodegeneration, including hyperoxia, dietary paraquat, and heat stress. We show that the fly ortholog, Glial Lazarillo, is strongly up-regulated in response to these extrinsic stresses and also can protect in vitro-cultured cells in situations modeling Alzheimer's disease (AD) and Parkinson's disease (PD). In adult flies, hApoD overexpression reduces age-associated lipid peroxide accumulation, suggesting a proximal mechanism of action. Similar data obtained in the mouse [Ganfornina, M.D., et al., (2008) Apolipoprotein D is involved in the mechanisms regulating protection from oxidative stress. Aging Cell 10.1111/j.1474-9726.2008.00395.] as well as in plants (Charron et al., personal communication) suggest that ApoD and its orthologs play an evolutionarily conserved role in response to stress, possibly managing or preventing lipid peroxidation. PMID:18458334

  17. Human ApoD, an apolipoprotein up-regulated in neurodegenerative diseases, extends lifespan and increases stress resistance in Drosophila.

    PubMed

    Muffat, Julien; Walker, David W; Benzer, Seymour

    2008-05-13

    Apolipoprotein D (ApoD) expression increases in several neurological disorders and in spinal cord injury. We provide a report of a physiological role for human ApoD (hApoD): Flies overexpressing hApoD are long-lived and protected against stress conditions associated with aging and neurodegeneration, including hyperoxia, dietary paraquat, and heat stress. We show that the fly ortholog, Glial Lazarillo, is strongly up-regulated in response to these extrinsic stresses and also can protect in vitro-cultured cells in situations modeling Alzheimer's disease (AD) and Parkinson's disease (PD). In adult flies, hApoD overexpression reduces age-associated lipid peroxide accumulation, suggesting a proximal mechanism of action. Similar data obtained in the mouse [Ganfornina, M.D., et al., (2008) Apolipoprotein D is involved in the mechanisms regulating protection from oxidative stress. Aging Cell 10.1111/j.1474-9726.2008.00395.] as well as in plants (Charron et al., personal communication) suggest that ApoD and its orthologs play an evolutionarily conserved role in response to stress, possibly managing or preventing lipid peroxidation.

  18. Binding and repressive activities of apolipoprotein E3 and E4 isoforms on the human ApoD promoter.

    PubMed

    Levros, Louis-Charles; Labrie, Marilyne; Charfi, Cyndia; Rassart, Eric

    2013-12-01

    Apolipoprotein D (ApoD) gene expression is increased in several neurological disorders such as Alzheimer's disease (AD) and multiple sclerosis. We previously showed that transgenic mice that overexpress human ApoD show a better resistance against paraquat or OC43 coronavirus-induced neurodegeneration. Here, we identified several nuclear factors from the cortex of control and OC43-infected mice which bind a fragment of the proximal ApoD promoter in vitro. Of interest, we detected apolipoprotein E (ApoE). Human ApoE consists of three isoforms (E2, E3, and E4) with the E4 and E2 alleles representing a greater and a lower risk for developping AD, respectively. Our results show that ApoE is located in the nucleus and on the ApoD promoter in human hepatic and glioblastoma cells lines. Furthermore, overexpression of ApoE3 and ApoE4 isoforms but not ApoE2 significantly inhibited the ApoD promoter activity in U87 cells (E3/E3 genotype) cultured under normal or different stress conditions while ApoE knock-down by siRNA had a converse effect. Consistent with these results, we also demonstrated by ChIP assay that E3 and E4 isoforms, but not E2, bind the ApoD promoter. Moreover, using the Allen Brain Atlas in situ hybridization database, we observed an inverse correlation between ApoD and ApoE mRNA expression during development and in several regions of the mouse brain, notably in the cortex, hippocampus, plexus choroid, and cerebellum. This negative correlation was also observed for cortex layers IV-VI based on a new Transcriptomic Atlas of the Mouse Neocortical Layers. These findings reveal a new function for ApoE by regulating ApoD gene expression.

  19. Liver proteomic response to hypertriglyceridemia in human-apolipoprotein C-III transgenic mice at cellular and mitochondrial compartment levels

    PubMed Central

    2014-01-01

    Background Hypertriglyceridemia (HTG) is defined as a triglyceride (TG) plasma level exceeding 150 mg/dl and is tightly associated with atherosclerosis, metabolic syndrome, obesity, diabetes and acute pancreatitis. The present study was undertaken to investigate the mitochondrial, sub-mitochondrial and cellular proteomic impact of hypertriglyceridemia in the hepatocytes of hypertriglyceridemic transgenic mice (overexpressing the human apolipoproteinC-III). Methods Quantitative proteomics (2D-DIGE) analysis was carried out on both “low-expressor” (LE) and “high-expressor” (HE) mice, respectively exhibiting moderate and severe HTG, to characterize the effect of the TG plasma level on the proteomic response. Results The mitoproteome analysis has revealed a large-scale phenomenon in transgenic mice, i.e. a general down-regulation of matricial proteins and up-regulation of inner membrane proteins. These data also demonstrate that the magnitude of proteomic changes strongly depends on the TG plasma level. Our different analyses indicate that, in HE mice, the capacity of several metabolic pathways is altered to promote the availability of acetyl-CoA, glycerol-3-phosphate, ATP and NADPH for TG de novo biosynthesis. The up-regulation of several cytosolic ROS detoxifying enzymes has also been observed, suggesting that the cytoplasm of HTG mice is subjected to oxidative stress. Moreover, our results suggest that iron over-accumulation takes place in the cytosol of HE mice hepatocytes and may contribute to enhance oxidative stress and to promote cellular proliferation. Conclusions These results indicate that the metabolic response to HTG in human apolipoprotein C-III overexpressing mice may support a high TG production rate and that the cytosol of hepatocytes is subjected to an important oxidative stress, probably as a result of FFA over-accumulation, iron overload and enhanced activity of some ROS-producing catabolic enzymes. PMID:25047818

  20. Apolipoprotein D

    PubMed Central

    Muffat, Julien; Walker, David W.

    2013-01-01

    “It’s got to be doing something important!”—Seymour Benzer, reflecting on the observation that ApoD mRNA levels increase 500-fold following neuronal crush injury. Seymour Benzer’s curiosity was legendary and seemingly limitless.1-5 Towards the end of his life, one of the (many) questions that kept him awake at night concerned the emerging role of Apolipoprotein D (ApoD) in aging and neurological disease. In this perspective, we will discuss the clinical and biochemical data on ApoD, and the input from the recent genetic studies in model systems, including those from the Benzer lab. PMID:20023409

  1. Association of a genetic polymorphism in human apolipoprotein B-100 with intermediate density lipoprotein concentrations.

    PubMed

    Robinson, M T; Butler, R; Krauss, R M

    1991-09-01

    Immunochemical techniques have been used to identify five antigenic (Ag) sites on apolipoprotein B-100 (apoB), the major protein constituent of very low density (VLDL), intermediate density (IDL), and low density lipoproteins (LDL). Each Ag site results from allelic variation at a specific locus of the apoB gene. In the present study, we assessed whether variations in the five Ag loci were associated with concentrations of plasma lipids or lipoprotein fractions measured by analytical ultracentrifugation in a group of 44 healthy men. Pair-wise analyses of the Ag markers revealed that Ag(a1/d), in association with either Ag(x/y) or Ag(t/z), is significantly related to plasma IDL-mass concentrations. In this cohort we detected no significant associations of the Ag alleles (singly or in combination) with plasma total cholesterol, triglycerides, LDL-cholesterol, HDL-cholesterol, or mass of total VLDL or LDL. These results suggest that genetic variations in the apoB molecule may predispose to variations in concentrations of IDL that could have consequences for atherosclerotic risk.

  2. Mechanism of lipid lowering in mice expressing human apolipoprotein A5

    SciTech Connect

    Fruchart-Najib, Jamila; Bauge, Eric; Niculescu, Loredan-Stefan; Pham, Tatiana; Thomas, Benoit; Rommens, Corinne; Majd, Zouher; Brewer, Bryan; Rubin, Edward M.; Pennacchio, Len A.; Fruchart, Jean-Charles

    2004-01-15

    Recently, we reported that apoAV plays key role in triglycerides lowering. Here, we attempted to determine the mechanism underlying this hypotriglyceridemic effect. We showed that triglyceride turnover is faster in hAPOA5 transgenic compared to wild type mice. Moreover, both apoB and apoCIII are decreased and LPL activity is increased in postheparin plasma of hAPOA5 transgenic mice. These data suggest a decrease in size and number of VLDL. To further investigate the mechanism of hAPOA5 in hyperlipidemic background, we intercrossed hAPOA5 and hAPOC3 transgenic mice. The effect resulted in a marked decreased of VLDL triglyceride, cholesterol, apolipoproteins B and CIII. In postprandial state, the triglyceride response is abolished in hAPOA5 transgenic mice. We demonstrated that in response to the fat load in hAPOA5XhAPOC3 mice, apoAV shifted from HDL to VLDL, probably to limit the elevation of triglycerides. In vitro, apoAV activates lipoprotein lipase. However, apoAV does not interact with LPL but interacts physically with apoCIII. This interaction does not seem to displace apoCIII from VLDL but may induce conformational change in apoCIII and consequently change in its function leading the activation of lipoprotein lipase.

  3. A Highly Expressed Human Protein, Apolipoprotein B-100, Serves as an Autoantigen in a Subgroup of Patients With Lyme Disease.

    PubMed

    Crowley, Jameson T; Drouin, Elise E; Pianta, Annalisa; Strle, Klemen; Wang, Qi; Costello, Catherine E; Steere, Allen C

    2015-12-01

    To discover novel autoantigens associated with Lyme arthritis (LA), we identified T-cell epitopes presented in vivo by human leukocyte antigen (HLA)-DR molecules in patients' inflamed synovial tissue or joint fluid and tested each epitope for autoreactivity. Using this approach, we identified the highly expressed human protein, apolipoprotein B-100 (apoB-100), as a target of T- and B-cell responses in a subgroup of LA patients. Additionally, the joint fluid of these patients had markedly elevated levels of apoB-100 protein, which may contribute to its autoantigenicity. In patients with antibiotic-refractory LA, the magnitude of apoB-100 antibody responses correlated with increased numbers of plasma cells in synovial tissue, greater numbers and activation of endothelial cells, and more synovial fibroblast proliferation. Thus, a subset of LA patients have high levels of apoB-100 in their joints and autoreactive T- and B-cell responses to the protein, which likely contributes to pathogenic autoimmunity in patients with antibiotic-refractory LA.

  4. A plasma lipoprotein containing only apolipoprotein E and with gamma mobility on electrophoresis releases cholesterol from cells.

    PubMed Central

    Huang, Y; von Eckardstein, A; Wu, S; Maeda, N; Assmann, G

    1994-01-01

    Previous studies have identified lipid-poor high density lipoproteins with electrophoretic pre-beta mobility as the initial acceptors of cell-derived cholesterol in human plasma. These lipoproteins contain apolipoprotein A-I (apo A-I) as their sole apolipoprotein. In the present study, incubation of human plasma with [3H]cholesterol-laden skin fibroblasts has led to the identification of another lipoprotein that serves as a potent initial acceptor of cell-derived cholesterol. This lipoprotein, which we term gamma-LpE, exhibits gamma mobility on agarose gel electrophoresis. As determined by nondenaturing PAGE and by electron microscopy, the size of the spherical particle ranges between 12 and 16 nm. SDS/PAGE and subsequent immunoblotting identified apoE as its sole apolipoprotein. Plasma from normal and apoA-I-deficient mice, but not from apoE-deficient mice, released [3H]cholesterol from fibroblasts into a gamma-migrating lipoprotein. Cell culture media from hepatoma cells or mouse peritoneal macrophages, both of which contain apoE of cellular origin, also promoted efflux of [3H]cholesterol from fibroblasts into a gamma-migrating fraction. This was not observed with cell culture medium from fibroblasts alone. In conclusion, our results strongly indicate the presence in human plasma of a lipoprotein containing only apoE, gamma-LpE, which is secreted by peripheral cells and is a potent acceptor of cell-derived cholesterol. Images PMID:8127890

  5. Human apolipoprotein E allele and docosahexaenoic acid intake modulate peripheral cholesterol homeostasis in mice.

    PubMed

    Pinçon, Anthony; Coulombe, Jean-Denis; Chouinard-Watkins, Raphaël; Plourde, Mélanie

    2016-08-01

    Carrying at least one apolipoprotein E ε4 allele (E4+) is the main genetic risk factor for Alzheimer's disease (AD). Epidemiological studies support that consuming fatty fish rich in docosahexaenoic acid (DHA; 22:6ω3) is protective against development of AD. However, this protective effect seems not to hold in E4+. The involvement of APOE genotype on the relationship between DHA intake and cognitive decline could be mediated through cholesterol. Many studies show a link between cholesterol metabolism and AD progression. In this study, we investigated whether cholesterol metabolism is improved in E3+ and E4+ mice consuming a diet rich in DHA. Plasma cholesterol was 36% lower in E4+ mice compared to E3+ mice fed the control diet (P=.02), and in the liver, there was a significant genotype effect where cholesterol levels were 18% lower in E4+ mice than E3+ mice. The low-density lipoprotein receptor was overexpressed in the liver of E4+ mice. Plasma cholesterol levels were 33% lower after the DHA diet (P=.02) in E3+ mice only, and there was a significant diet effect where cholesterol level was 67% lower in the liver of mice fed DHA. Mice fed the DHA diet also had 62% less lipolysis stimulated lipoprotein receptor expression in the liver compared to mice fed the control diet (P<.0001), but there was no genotype effect. These findings suggest that plasma and liver cholesterol homeostasis and the receptors regulating uptake of cholesterol in the liver are modulated differently and independently by APOE allele and DHA intake.

  6. Contrasting in vivo effects of murine and human apolipoprotein A-II. Role of monomer versus dimer.

    PubMed

    Gong, E L; Stoltfus, L J; Brion, C M; Murugesh, D; Rubin, E M

    1996-03-15

    The role of apolipoprotein A-II (apoA-II) in high density lipoprotein (HDL) structure and metabolism has been studied previously in transgenic mice overexpressing either human or murine apoA-II. These studies have shown differences between these two groups of transgenic animals in the levels of very low density, low density, and high density lipoproteins, in the HDL particle size distribution, and in the relationship between apoA-II levels and lipoprotein levels. To determine whether these differences are due to the fact that human apoA-II is dimeric and murine apoA-II monomeric, we have examined the effects of monomeric human apoA-II (hA-IImon) in transgenic mice. Site-directed mutagenesis (Cys6 -> Ser) was used to generate 15 transgenic founder lines of hA-IImon mice, that contained plasma hA-IImon concentrations over a 10-fold range (11 mg/dl to 185 mg/dl). The hA-IImon floated in the d < or = 1.21 g/ml fraction and migrated as an apoA-II monomer by nonreducing SDS-polyacrylamide gel electrophoresis. HDL levels were not correlated with hA-IImon levels (r = -0.26); HDL particle size and size distribution, as well as very low density and low density lipoprotein levels and sizes, were unchanged compared to nontransgenic control mice. These results suggest that differences between mice overexpressing human dimeric apoA-II and those overexpressing murine apoA-II are the result of sequence differences between these two apoA-II molecules and are not solely due to the fact that human apoA-II exists as a dimer.

  7. Sphingosine 1-phosphate and its carrier apolipoprotein M in human sepsis and in Escherichia coli sepsis in baboons.

    PubMed

    Frej, Cecilia; Linder, Adam; Happonen, Kaisa E; Taylor, Fletcher B; Lupu, Florea; Dahlbäck, Björn

    2016-06-01

    Sphingosine 1-phosphate (S1P) is an important regulator of vascular integrity and immune cell migration, carried in plasma by high-density lipoprotein (HDL)-associated apolipoprotein M (apoM) and by albumin. In sepsis, the protein and lipid composition of HDL changes dramatically. The aim of this study was to evaluate changes in S1P and its carrier protein apoM during sepsis. For this purpose, plasma samples from both human sepsis patients and from an experimental Escherichia coli sepsis model in baboons were used. In the human sepsis cohort, previously studied for apoM, plasma demonstrated disease-severity correlated decreased S1P levels, the profile mimicking that of plasma apoM. In the baboons, a similar disease-severity dependent decrease in plasma levels of S1P and apoM was observed. In the lethal E. coli baboon sepsis, S1P decreased already within 6-8 hrs, whereas the apoM decrease was seen later at 12-24 hrs. Gel filtration chromatography of plasma from severe human or baboon sepsis on Superose 6 demonstrated an almost complete loss of S1P and apoM in the HDL fractions. S1P plasma concentrations correlated with the platelet count but not with erythrocytes or white blood cells. The liver mRNA levels of apoM and apoA1 decreased strongly upon sepsis induction and after 12 hr both were almost completely lost. In conclusion, during septic challenge, the plasma levels of S1P drop to very low levels. Moreover, the liver synthesis of apoM decreases severely and the plasma levels of apoM are reduced. Possibly, the decrease in S1P contributes to the decreased endothelial barrier function observed in sepsis. PMID:26990127

  8. Modification by acrolein, a component of tobacco smoke and age-related oxidative stress, mediates functional impairment of human apolipoprotein E.

    PubMed

    Tamamizu-Kato, Shiori; Wong, Jason Yiu; Jairam, Vikram; Uchida, Koji; Raussens, Vincent; Kato, Hiroyuki; Ruysschaert, Jean-Marie; Narayanaswami, Vasanthy

    2007-07-17

    Oxidative damage to proteins such as apolipoprotein B-100 increases the atherogenicity of low-density lipoproteins (LDL). However, little is known about the potential oxidative damage to apolipoprotein E (apoE), an exchangeable antiatherogenic apolipoprotein. ApoE plays an integral role in lipoprotein metabolism by regulating the plasma cholesterol and triglyceride levels. Hepatic uptake of lipoproteins is facilitated by apoE's ability to bind with cell surface heparan sulfate proteoglycans and to lipoprotein receptors via basic residues in its 22 kDa N-terminal domain (NT). We investigated the effect of acrolein, an aldehydic product of endogenous lipid peroxidation and a tobacco smoke component, on the conformation and function of recombinant human apoE3-NT. Acrolein caused oxidative modification of apoE3-NT as detected by Western blot with acrolein-lysine-specific antibodies, and tertiary conformational alterations. Acrolein modification impairs the ability of apoE3-NT to interact with heparin and the LDL receptor. Furthermore, acrolein-modified apoE3-NT displayed a 5-fold decrease in its ability to interact with lipid surfaces. Our data indicate that acrolein disrupts the functional integrity of apoE3, which likely interferes with its role in regulating plasma cholesterol homeostasis. These observations have implications regarding the role of apoE in the pathogenesis of smoking- and oxidative stress-mediated cardiovascular and cerebrovascular diseases.

  9. Hydrogen/Deuterium Exchange and Molecular Dynamics Analysis of Amyloid Fibrils Formed by a D69K Charge-Pair Mutant of Human Apolipoprotein C-II.

    PubMed

    Mao, Yu; Zlatic, Courtney O; Griffin, Michael D W; Howlett, Geoffrey J; Todorova, Nevena; Yarovsky, Irene; Gooley, Paul R

    2015-08-11

    Plasma apolipoproteins form amphipathic α helices in lipid environments but in the lipid-free state show a high propensity to form β structure and self-associate into amyloid fibrils. The widespread occurrence of apolipoproteins in amyloid plaques suggests disease-related roles, specifically in atherosclerosis. To reconcile the dual abilities of apolipoproteins to form either α helices or cross-β sheet structures, we examined fibrils formed by human apolipoprotein C-II (apoC-II). A structural model for apoC-II fibrils shows a cross-β core with parallel β strands, including a buried K30-D69 charge pair. We investigated the effect of abolishing this charge pair in mutant D69K apoC-II. Fluorescence studies indicated more rapid fibril formation and less solvent accessibility of tryptophan (W26) in D69K apoC-II fibrils than in wild-type (WT) fibrils. X-ray diffraction data of aligned D69K apoC-II fibrils yielded a typical cross-β structure with increased β sheet spacing compared to that of WT fibrils. Hydrogen/deuterium (H/D) exchange patterns were similar for D69K apoC-II fibrils compared to WT fibrils, albeit with an overall reduction in the level of slow H/D exchange, particularly around residues 29-32. Molecular dynamics simulations indicated reduced β strand content for a model D69K apoC-II tetramer compared to the WT tetramer and confirmed an expansion of the cross-β spacing that contributed to the formation of a stable charge pair between K69 and E27. The results highlight the importance of charge-pair interactions within the apoC-II fibril core, which together with numerous salt bridges in the flexible connecting loop play a major role in the ability of lipid-free apoC-II to form stable cross-β fibrils.

  10. Characteristics of polymorphism at a VNTR locus 3[prime] to the apolipoprotein B gene in five human populations

    SciTech Connect

    Deka, R.; DeCroo, S.; Ferrell, R.E. ); Chakraborty, R.; Barton, S.A. ); Rothhammer, F. )

    1992-12-01

    The authors have analyzed the allele frequency distribution at the hypervariable locus 3[prime] to the apolipoprotein B gene (ApoB 3[prime] VNTR) in five well-defined human populations (Kacharis of northeast India, New Guinea Highlanders of Papua New Guinea, Dogrib Indians of Canada, Pehuenche Indians of Chile, and a relatively homogeneous Caucasian population of northern German extraction) by using the PCR technique. A total of 12 segregating alleles were detected in the pooled sample of 319 individuals. A fairly consistent bimodal pattern of allele frequency distribution, apparent in most of these geographically and genetically diverse populations, suggests that the ApoB 3[prime] VNTR polymorphism predates the geographic dispersal of ancestral human populations. In spite of the observed high degree of polymorphism at this locus (expected heterozygosity levels 55%-78%), the genotype distributions in all populations (irrespective of their tribal or cosmopolitan nature) conform to their respective Hardy-Weinberg predictions. Furthermore, analysis of the congruence between expected heterozygosity and the observed number of alleles reveals that, in general, the allele frequency distributions at this locus are in agreement with the predictions of the classical mutation-drift models. The data also show that alleles that are shared by all populations have the highest average frequency within populations. These findings demonstrate the potential utility of highly informative hypervariable loci such as the ApoB 3[prime] VNTR locus in population genetic research, as well as in forensic medicine and determination of biological relatedness of individuals. 38 refs., 2 figs., 3 tabs.

  11. Fibrates increase human apolipoprotein A-II expression through activation of the peroxisome proliferator-activated receptor.

    PubMed Central

    Vu-Dac, N; Schoonjans, K; Kosykh, V; Dallongeville, J; Fruchart, J C; Staels, B; Auwerx, J

    1995-01-01

    In view of the evidence linking plasma high density lipoprotein (HDL)-cholesterol levels to a protective effect against coronary artery disease and the widespread use of fibrates in the treatment of hyperlipidemia, the goal of this study was to analyze the influence of fibrates on the expression of apolipoprotein (apo) A-II, a major protein constituent of HDL. Administration of fenofibrate (300 mg/d) to 16 patients with coronary artery disease resulted in a marked increase in plasma apo A-II concentrations (0.34 +/- 0.11 to 0.45 +/- 0.17 grams/liter; P < 0.01). This increase in plasma apo A-II was due to a direct effect on hepatic apo A-II production, since fenofibric acid induced apo A-II mRNA levels to 450 and 250% of control levels in primary cultures of human hepatocytes and in human hepatoblastoma HepG2 cells respectively. The induction in apo A-II mRNA levels was followed by an increase in apo A-II secretion in both cell culture systems. Transient transfection experiments of a reporter construct driven by the human apo A-II gene promoter indicated that fenofibrate induced apo A-II gene expression at the transcriptional level. Furthermore, several other peroxisome proliferators, such as the fibrate, Wy-14643, and the fatty acid, eicosatetraynoic acid (ETYA), also induced apo A-II gene transcription. Unilateral deletions and site-directed mutagenesis identified a sequence element located in the J-site of the apo A-II promoter mediating the responsiveness to fibrates and fatty acids. This element contains two imperfect half sites spaced by 1 oligonucleotide similar to a peroxisome proliferator responsive element (PPRE). Cotransfection assays showed that the peroxisome proliferator activated receptor (PPAR) transactivates the apo A-II promoter through this AII-PPRE. Gel retardation assays demonstrated that PPAR binds to the AII-PPRE with an affinity comparable to its binding affinity to the acyl coA oxidase (ACO)-PPRE. In conclusion, in humans fibrates increase

  12. Glycosylation and Sialylation of Macrophage-derived Human Apolipoprotein E Analyzed by SDS-PAGE and Mass Spectrometry

    PubMed Central

    Lee, Youra; Kockx, Maaike; Raftery, Mark J.; Jessup, Wendy; Griffith, Renate; Kritharides, Leonard

    2010-01-01

    Apolipoprotein E (apoE) is a 34-kDa glycoprotein secreted from various cells including hepatocytes and macrophages and plays an important role in remnant lipoprotein clearance, immune responses, Alzheimer disease, and atherosclerosis. Cellular apoE and plasma apoE exist as multiple glycosylated and sialylated glycoforms with plasma apoE being less glycosylated/sialylated than cell-derived apoE. Some of the glycan structures on plasma apoE are characterized; however, the more complicated structures on plasma and cellular/secreted apoE remain unidentified. We investigated glycosylation and sialylation of cellular and secreted apoE from primary human macrophages by one- and two-dimensional gel electrophoresis and mass spectrometry. Our results identify eight different glycoforms with (HexNAc)2-Hex2-(NeuAc)2 being the most complex glycan detected on Thr194 in both cellular and secreted apoE. Four additional glycans were identified on apoE(283–299), and using β-elimination/alkylation by methylamine in vitro, we identified Ser290 as a novel site of glycan attachment. Comparison of plasma and cellular/secreted apoE from the same donor confirmed that cell-derived apoE is more extensively sialylated than plasma apoE. Given the importance of the C terminus of apoE in regulating apoE solubility, stability, and lipid binding, these results may have important implications for our understanding of apoE biochemistry. PMID:20511397

  13. Distinct Roles of Apolipoproteins A1 and E in the Modulation of High-Density Lipoprotein Composition and Function.

    PubMed

    Filou, Serafoula; Lhomme, Marie; Karavia, Eleni A; Kalogeropoulou, Christina; Theodoropoulos, Vassilis; Zvintzou, Evangelia; Sakellaropoulos, George C; Petropoulou, Peristera-Ioanna; Constantinou, Caterina; Kontush, Anatol; Kypreos, Kyriakos E

    2016-07-12

    In addition to high-density lipoprotein cholesterol (HDL-C) levels, HDL quality also appears to be very important for atheroprotection. Analysis of various clinical paradigms suggests that the lipid and apolipoprotein composition of HDL defines its size, shape, and functions and may determine its beneficial effects on human health. Previously, we reported that like apolipoprotein A-I (Apoa1), apolipoprotein E (Apoe) is also capable of promoting the de novo biogenesis of HDL with the participation of ATP binding cassette A lipid transporter member 1 (Abca1) and plasma enzyme lecithin:cholesterol acyltransferase (Lcat), in a manner independent of a functional Apoa1. Here, we performed a comparative analysis of the functions of these HDL subpopulations. Specifically, Apoe and Apoa1 double-deficient (Apoe(-/-) × Apoa1(-/-)) mice were infected with APOA1- or APOE3-expressing adenoviruses, and APOA1-containing HDL (APOA1-HDL) and APOE3-containing HDL (APOE3-HDL), respectively, were isolated and analyzed by biochemical and physicochemical methods. Western blot and lipidomic analyses indicated significant differences in the apolipoprotein and lipid composition of the two HDL species. Moreover APOE3-HDL presented a markedly reduced antioxidant potential and Abcg1-mediated cholesterol efflux capacity. Surprisingly, APOE3-HDL but not APOA1-HDL attenuated LPS-induced production of TNFα in RAW264.7 cells, suggesting that the anti-inflammatory effects of APOA1 are dependent on APOE expression. Taken together, our data indicate that APOA1 and APOE3 recruit different apolipoproteins and lipids on the HDL particle, leading to structurally and functionally distinct HDL subpopulations. The distinct role of these two apolipoproteins in the modulation of HDL functionality may pave the way toward the development of novel pharmaceuticals that aim to improve HDL functionality. PMID:27332083

  14. Unique structural properties of apolipoprotein B in low-density lipoproteins produced by several human hepatoma-derived cell lines.

    PubMed

    La Belle, M; McCall, M R; Krauss, R M; Forte, T M

    1990-10-01

    Previous work has shown that low-density lipoproteins (LDL) secreted by hepatoma-derived cell lines have an unusual composition compared to plasma LDL; rather than cholesteryl ester, the hepatoma cell-secreted LDL have a triacylglycerol core. We have found that they also have an increased negative charge, as judged by agarose electrophoresis. Since apolipoprotein B is a glycoprotein containing carbohydrate chains terminated with negatively charged sialic acid residues, we examined whether increased glycosylation of the apolipoprotein B from three hepatoma cell lines (Hep G2, Hep 3B and Huh 7) might account for the differences in LDL charge. The weight percent carbohydrate for Hep G2, Hep 3B and Huh 7 LDL-protein (1.1 +/- 0.2; 1.7 +/- 0.8; 0.4 +/- 0.1) was found to be extremely low compared with the 2.8-9% range we found for plasma LDL-protein, while the amount of LDL-lipid associated carbohydrate from hepatoma LDL was similar to that we found in plasma LDL. Furthermore, desialation of hepatoma cell-secreted LDL with neuraminidase did not normalize the negative charge to that of neuraminidase-treated plasma LDL. Western blots of thrombin proteolytic fragments indicated that, in addition to the T1-T4 fragments seen in plasma apolipoprotein B, apolipoprotein B of hepatoma-derived LDL produced four to five new fragments (T5-T9), suggesting increased exposure of proteolytic sites. Western blotting of the new fragments with antibodies specific for known apolipoprotein B sequences suggests that many of the new cleavage sites cluster in or near the putative LDL receptor recognition site.

  15. Characterization of the metabolic syndrome by apolipoproteins in the Oklahoma Cherokee.

    PubMed

    Alaupovic, Petar; Blackett, Piers; Wang, Wenyu; Lee, Elisa

    2008-01-01

    Native Americans are susceptible to type 2 diabetes and associated cardiovascular risk that precedes the diabetes. Nondiabetic Cherokee adolescents and young adults were studied for association of apolipoproteins A-I, B, and C-III with the metabolic syndrome, homeostasis model assessment-insulin resistance (HOMA-IR), and body mass index. Apolipoproteins, lipids, selected ratios, and HOMA-IR changed adversely according to the number of metabolic syndrome criteria present (P<.001 for trend). Logistic regression showed heparin-precipitated apolipoprotein C-III, apolipoprotein C-III bound to apolipoprotein B-containing lipoproteins, to be a significant predictor of the metabolic syndrome in the adolescents and adults, and it appears to be more strongly associated than apolipoprotein B: apolipoprotein A-I. Regression modeling with components of the syndrome as the dependent variables showed that they were all significantly associated with heparin-precipitated apolipoprotein C-III except for fasting blood glucose. The Cherokee have a high prevalence of the metabolic syndrome, which is associated with atherosclerotic lipoprotein particles containing apolipoprotein C-III and B. PMID:19040586

  16. Evaluation of the function of the human apolipoprotein B gene nuclear matrix association regions in transgenic mice.

    PubMed

    Wang, D M; Taylor, S; Levy-Wilson, B

    1996-10-01

    The human apolipoprotein B (apoB) gene resides in a 47.5 kb DNasel-sensitive chromosomal domain in hepatic and intestinal cells, flanked by the 5' distal matrix association region (MAR) and the 3' proximal MAR. A third MAR, the 5' proximal MAR, is found only in transcriptionally active hepatic (HepG2) cells. Hepatic expression of the apoB gene requires a tissue-specific promoter (-898 to +121) and an enhancer from the second intron of the gene (+360 to +1064). A vector containing this portion of the gene linked to the beta-galactosidase reporter is sufficient for low level expression in the livers of transgenic mice. Expression in transgenic mice was increased when the promoter-enhancer beta-gal vector was flanked by MARs. The results were similar whether the 5' distal, the 5' proximal or the 3' proximal MARs were placed at both ends of the construct, or whether the construct was flanked by the 5' distal and the 3' MAR, suggesting that the apoB MARs play a role in gene expression in vivo. When the MAR-containing constructs were transiently transfected into HepG2 cells, the resulting beta-gal activities were similar to that of the construct lacking MARs, thus demonstrating that the MARs do not exhibit any enhancer activity. Recent experiments (Kalos, M., and R. E. K. Fournier. 1995. Mol. Cell. Biol. 15: 198-207) examining stable integration of some of our constructs into human and rat hepatoma transfectants suggest that in single and double copy transfectants, the apoB MARs behave as boundary "insulators", protecting the integrated transgenes against position effects regardless of their site of integration. However, multicopy transfectants are transcriptionally inactive and when the MARs are absent, expression of the transgenes drops to background levels. Our results to date with single and low-copy number transgenes do not support an insulator function for the apoB MARs, although they appear to be required to increase the levels of expression.

  17. Apolipoprotein mRNA in liver and intestine of rats is affected by dietary beet fiber or cholestyramine.

    PubMed

    Sonoyama, K; Nishikawa, H; Kiriyama, S; Niki, R

    1995-01-01

    Rats were fed a cholesterol-free diet with no added fiber (fiber-free) or with 15 g/100 g beet fiber or 5 g/100 g cholestyramine for 14 d. Final plasma total cholesterol concentrations were significantly lower in rats fed beet fiber than in those fed fiber-free or cholestyramine diets. This difference was due mainly to lower HDL cholesterol concentrations. The group fed beet fiber also tended (P < 0.1) to have lower apolipoprotein A-I concentration in plasma. Northern blot analysis revealed that the relative concentrations of jejunal apolipoprotein A-I and A-IV mRNA were the same in all groups, whereas ileal apolipoprotein A-I and A-IV mRNA levels were significantly lower in rats fed beet fiber or cholestyramine than in those fed the fiber-free diet. Hepatic apolipoprotein E mRNA concentrations were the same in all groups, but apolipoprotein A-I mRNA levels were significantly lower in rats fed beet fiber than in those fed the other diets. Apolipoprotein A-IV mRNA tended (P < 0.1) to be lower in rats fed the beet fiber diet. These data suggest that the hypocholesterolemic effect of dietary beet fiber is associated with diminished expression of the hepatic apolipoprotein A-I gene.

  18. Hepatocyte nuclear factor 1 and C/EBP are essential for the activity of the human apolipoprotein B gene second-intron enhancer.

    PubMed Central

    Brooks, A R; Levy-Wilson, B

    1992-01-01

    The tissue-specific transcriptional enhancer of the human apolipoprotein B gene contains multiple protein-binding sites spanning 718 bp. Most of the enhancer activity is found in a 443-bp fragment (+621 to +1064) that is located entirely within the second intron of the gene. Within this fragment, a 147-bp region (+806 to +952) containing a single 97-bp DNase I footprint exhibits significant enhancer activity. We now report that this footprint contains four distinct protein-binding sites that have the potential to bind nine distinct liver nuclear proteins. One of these proteins was identified as hepatocyte nuclear factor 1 (HNF-1), which binds with relatively low affinity to the 5' half of a 20-bp palindrome located at the 5' end of the large footprint. A binding site for C/EBP (or one of the related proteins that recognize similar sequences) was identified in the center of the 97-bp footprint. This binding site is coincident or overlaps with the binding sites for five other proteins, two of which appear to be distinct from the C/EBP-related family of proteins. The binding site for a nuclear factor designated protein I is located between the HNF-1 and C/EBP binding sites. Finally, the 3'-most 15 bp of the footprinted sequence contain a binding site for another nuclear protein, which we have called protein II. Mutations that abolish the binding of either HNF-1, protein II, or the C/EBP-related proteins severely reduce enhancer activity. However, deletion experiments demonstrated that neither the HNF-1-binding site alone, nor the combination of binding sites for HNF-1, protein I, and C/EBP, nor the C/EBP-binding site plus the protein II-binding site is sufficient to enhance transcription from a strong apolipoprotein B promoter. Rather, HNF-1 and C/EBP act synergistically with protein II to enhance transcription of the apolipoprotein B gene. Images PMID:1545795

  19. Human factors involvement in bringing the power of AI to a heterogeneous user population

    NASA Technical Reports Server (NTRS)

    Czerwinski, Mary; Nguyen, Trung

    1994-01-01

    The Human Factors involvement in developing COMPAQ QuickSolve, an electronic problem-solving and information system for Compaq's line of networked printers, is described. Empowering customers with expert system technology so they could solve advanced networked printer problems on their own was a major goal in designing this system. This process would minimize customer down-time, reduce the number of phone calls to the Compaq Customer Support Center, improve customer satisfaction, and, most importantly, differentiate Compaq printers in the marketplace by providing the best, and most technologically advanced, customer support. This represents a re-engineering of Compaq's customer support strategy and implementation. In its first generation system, SMART, the objective was to provide expert knowledge to Compaq's help desk operation to more quickly and correctly answer customer questions and problems. QuickSolve is a second generation system in that customer support is put directly in the hands of the consumers. As a result, the design of QuickSolve presented a number of challenging issues. Because the produce would be used by a diverse and heterogeneous set of users, a significant amount of human factors research and analysis was required while designing and implementing the system. Research that shaped the organization and design of the expert system component as well.

  20. Dietary cholesterol and its effect on tau protein: a study in apolipoprotein E-deficient and P301L human tau mice.

    PubMed

    Glöckner, Frauke; Meske, Volker; Lütjohann, Dieter; Ohm, Thomas G

    2011-04-01

    Apolipoprotein E (ApoE) is the major cholesterol transporter in the brain. There is epidemiological and experimental evidence for involvement of cholesterol metabolism in the development and progression of Alzheimer disease. A dietary effect on tau phosphorylation or aggregation, or a role of apoE in tau metabolism, has been studied experimentally, but the data are ambiguous. To elucidate the relationship between cholesterol and tau, we studied mice expressing P301L mutant human tau but not apoE (htau-ApoE) and P301L mice with wild-type ApoE (htau- ApoE); both genotypes develop neuron cytoskeletal changes similar to those found in Alzheimer disease. Mice were kept on a cholesterol-enriched diet or control diet for 15 weeks. The numbers of neurons with hyperphosphorylated and conformationally changed tau in the cerebral cortex were assessed by immunohistochemistry, and sterol levels were determined. Highly elevated dietary serum cholesterol levels enhanced ongoing tau pathology in htau-ApoE mice; this effect correlated with elevated brain cholesterol metabolite 27-hydroxycholesterol levels. Apolipoprotein E deficiency promoted significant increases of tau phosphorylation and conformational changes in mice on a control diet. In htau-ApoE mice on the high cholesterol regimen, brain oxysterol levels were less than in htau-ApoE mice, and the numbers of neurons with pathologically altered tau were similar to those in htau-ApoE mice on the high-cholesterol diet.

  1. The gender-specific apolipoprotein E genotype influence on the distribution of plasma lipids and apolipoproteins in the population of Rochester, Minnesota. II. Regression relationships with concomitants

    SciTech Connect

    Reilly, S.L.; Sing, C.F. ); Ferrell, R.E. ); Kottke, B.A. )

    1992-12-01

    The influence of the apolipoprotein E (Apo E) polymorphism and gender on the regression relationships between each of nine plasma lipid and apolipoprotein traits (total cholesterol; ln triglycerides; high-density-lipoprotein chloesterol; apolipoproteins AI, AII, B, and CII; ln CIII; and ln E) and four concomitants (age, weight, waist-to-hip ratio, and smoking) was studied in 507 unrelated individuals representative of the adult population of Rochester, MN. Analyses are presented separately for females and males. Each lipid and apolipoprotein trait exhibited at least one Apo E genotype-specific regression relationship with the concomitants investigated in this study. In most cases the heterogeneity of regression was associated with differences between the [var epsilon]32 and [var epsilon]33 genotype. This study documents that the influence of Apo E genotype on average levels of plasma lipids and apolipoproteins varies among subdivisions of the population defined by age, body size, and smoking status. 61 refs., 1 fig., 5 tabs.

  2. An investigation of human apolipoproteins B and E polymorphisms in two African populations from Ethiopia and Benin.

    PubMed

    Corbo, R.M.; Scacchi, R.; Rickards, O.; Martinez-Labarga, C.; De Stefano, G.F.

    1999-01-01

    Three polymorphisms (XbaI, EcoRI, and Ins/Del) of the apolipoprotein B (APOB) gene and the polymorphism of apolipoprotein E (APOE) were investigated in two population samples of Amhara and Oromo origin from Ethiopia, and in two population samples of Bariba and Berba origin from Benin. No heterogeneity was observed within each major group. The cumulated frequencies of the APOB X+, R+, and D alleles for the Ethiopia and the Benin groups were 0.268 and 0.133, 0.958 and 0.818, 0.206 and 0.223, respectively. Regarding APOE, the cumulated allele frequencies of Ethiopia and Benin were 0.031 and 0.103 for epsilon*2 allele, 0.811 and 0.742 for epsilon*3, and 0.143 and 0.155 for epsilon*4, respectively. APOE typing performed at the protein level only in the Ethiopians revealed a variant allele, epsilon*5, found at the polymorphic level both in the Amhara and in the Oromo (cumulated frequency: 0.015). A tentative explanation for the higher frequencies of epsilon*4 and epsilon*5 alleles was sought in relation to the lifestyle and ethnicity of the two populations. Am. J. Hum. Biol. 11:297-304, 1999. Copyright 1999 Wiley-Liss, Inc.

  3. High prevalence of hypertriglyceridaemia and apolipoprotein abnormalities in coronary artery disease.

    PubMed Central

    Barbir, M; Wile, D; Trayner, I; Aber, V R; Thompson, G R

    1988-01-01

    Serum lipids and apolipoproteins A-I and B were measured in 174 men aged less than 60 with angiographically confirmed coronary artery disease and in 572 healthy control men. Two thirds of the patients had raised age-corrected values of fasting serum cholesterol and/or triglyceride and/or a low high density lipoprotein (HDL) cholesterol compared with the controls. Eighteen (30%) of the 61 normolipidaemic patients had a concentration of serum apolipoprotein A-I below the 5th percentile of 233 controls. In normolipidaemic patients on beta blockers the relative prevalence of serum low density lipoprotein (LDL)-apolipoprotein B values above the 95th percentile of 339 controls was significantly increased. Discriminant function analysis showed that a raised concentration of serum triglyceride was the best discriminant between patients and controls, with raised LDL-apolipoprotein B and reduced apolipoprotein A-I coming second only to triglyceride in analyses where each was separately compared with all the lipid variables. These associations were highly significant and were independent of other influences, including beta blockade. These findings re-emphasise the importance of hypertriglyceridaemia as a risk factor and confirm that apolipoprotein abnormalities occur frequently in coronary disease, even in normolipidaemic patients. PMID:3203033

  4. Targeting nanodisks via a single chain variable antibody - Apolipoprotein chimera

    SciTech Connect

    Iovannisci, David M.; Beckstead, Jennifer A.; Ryan, Robert O.

    2009-02-06

    Nanodisks (ND) are nanometer scale complexes of phospholipid and apolipoprotein that have been shown to function as drug delivery vehicles. ND harboring significant quantities of the antifungal agent, amphotericin B, or the bioactive isoprenoid, all trans retinoic acid, have been generated and characterized. As currently formulated, ND possess limited targeting capability. In this study, we constructed a single chain variable antibody (scFv).apolipoprotein chimera and assessed the ability of this fusion protein to form ND and recognize the antigen to which the scFv is directed. Data obtained revealed that {alpha}-vimentin scFv.apolipoprotein A-I is functional in ND formation and antigen recognition, opening the door to the use of such chimeras in targeting drug-enriched ND to specific tissues.

  5. New potential role of serum apolipoprotein E mediated by its binding to clumping factor A during Staphylococcus aureus invasive infections to humans

    PubMed Central

    Hair, Pamela S.; Nyalwidhe, Julius O.; Cunnion, Kenji M.

    2015-01-01

    Staphylococcus aureus is a crucial human pathogen expressing various immune-evasion proteins that interact with the host-cell molecules. Clumping factor A (ClfA) is a microbial surface protein that promotes S. aureus binding to fibrinogen, and is associated with septic arthritis and infective endocarditis. In order to identify the major human serum proteins that bind the ClfA, we utilized recombinant ClfA region A in a plate-based assay. SDS-PAGE analysis of the bound proteins yielded five prominent bands, which were analysed by MS yielding apolipoprotein E (ApoE) as the predominant protein. ClfA-sufficient S. aureus bound purified ApoE by more than one log greater than an isogenic ClfA-deficient mutant. An immunodot-blot assay yielded a linearity model for ClfA binding to human ApoE with a stoichiometric-binding ratio of 1.702 at maximal Pearson's correlation coefficient (0.927). These data suggest that ApoE could be a major and novel binding target for the S. aureus virulence factor ClfA. Thus, ClfA recruitment of serum ApoE to the S. aureus surface may sequester ApoE and blunt its host defence function against S. aureus-invasive infections to humans. In this context, compounds that can block or suppress ClfA binding to ApoE might be utilized as prophylactic or therapeutic agents. PMID:25878259

  6. Plasma lipoproteins as mediators of the oxidative stress induced by UV light in human skin: a review of biochemical and biophysical studies on mechanisms of apolipoprotein alteration, lipid peroxidation, and associated skin cell responses.

    PubMed

    Filipe, Paulo; Morlière, Patrice; Silva, João N; Mazière, Jean-Claude; Patterson, Larry K; Freitas, João P; Santus, R

    2013-01-01

    There are numerous studies concerning the effect of UVB light on skin cells but fewer on other skin components such as the interstitial fluid. This review highlights high-density lipoprotein (HDL) and low-density lipoprotein (LDL) as important targets of UVB in interstitial fluid. Tryptophan residues are the sole apolipoprotein residues absorbing solar UVB. The UVB-induced one-electron oxidation of Trp produces (•)Trp and (•)O2 (-) radicals which trigger lipid peroxidation. Immunoblots from buffered solutions or suction blister fluid reveal that propagation of photooxidative damage to other residues such as Tyr or disulfide bonds produces intra- and intermolecular bonds in apolipoproteins A-I, A-II, and B100. Partial repair of phenoxyl tyrosyl radicals (TyrO(•)) by α -tocopherol is observed with LDL and HDL on millisecond or second time scales, whereas limited repair of α -tocopherol by carotenoids occurs in only HDL. More effective repair of Tyr and α -tocopherol is observed with the flavonoid, quercetin, bound to serum albumin, but quercetin is less potent than new synthetic polyphenols in inhibiting LDL lipid peroxidation or restoring α -tocopherol. The systemic consequences of HDL and LDL oxidation and the activation and/or inhibition of signalling pathways by oxidized LDL and their ability to enhance transcription factor DNA binding activity are also reviewed.

  7. Plasma Lipoproteins as Mediators of the Oxidative Stress Induced by UV Light in Human Skin: A Review of Biochemical and Biophysical Studies on Mechanisms of Apolipoprotein Alteration, Lipid Peroxidation, and Associated Skin Cell Responses

    PubMed Central

    Filipe, Paulo; Morlière, Patrice; Silva, João N.; Mazière, Jean-Claude; Patterson, Larry K.; Freitas, João P.; Santus, R.

    2013-01-01

    There are numerous studies concerning the effect of UVB light on skin cells but fewer on other skin components such as the interstitial fluid. This review highlights high-density lipoprotein (HDL) and low-density lipoprotein (LDL) as important targets of UVB in interstitial fluid. Tryptophan residues are the sole apolipoprotein residues absorbing solar UVB. The UVB-induced one-electron oxidation of Trp produces •Trp and •O2− radicals which trigger lipid peroxidation. Immunoblots from buffered solutions or suction blister fluid reveal that propagation of photooxidative damage to other residues such as Tyr or disulfide bonds produces intra- and intermolecular bonds in apolipoproteins A-I, A-II, and B100. Partial repair of phenoxyl tyrosyl radicals (TyrO•) by α-tocopherol is observed with LDL and HDL on millisecond or second time scales, whereas limited repair of α-tocopherol by carotenoids occurs in only HDL. More effective repair of Tyr and α-tocopherol is observed with the flavonoid, quercetin, bound to serum albumin, but quercetin is less potent than new synthetic polyphenols in inhibiting LDL lipid peroxidation or restoring α-tocopherol. The systemic consequences of HDL and LDL oxidation and the activation and/or inhibition of signalling pathways by oxidized LDL and their ability to enhance transcription factor DNA binding activity are also reviewed. PMID:23738035

  8. Baculovirus-mediated expression of human apolipoprotein E in Manduca sexta larvae generates particles that bind to the low density lipoprotein receptor.

    PubMed Central

    Gretch, D G; Sturley, S L; Friesen, P D; Beckage, N E; Attie, A D

    1991-01-01

    Human apolipoprotein E (apoE) is a ligand for the low density lipoprotein (LDL) receptor and mediates the catabolism of several classes of lipoprotein particles. Binding of apoE to the LDL receptor requires association of apoE with lipid in a vesicle or a lipoprotein particle. Because of this requirement, purified apoE or apoE derived directly from bacterial expression systems does not bind to the LDL receptor. To overcome this problem and to facilitate analysis of apoE structure, recombinant baculoviruses containing the human apoE cDNA fused to the polyhedrin promoter of Autographa californica nuclear polyhedrosis virus were constructed. The recombinant viruses were used to infect larvae of the tobacco hornworm Manduca sexta in vivo. High levels of lipoprotein particles containing human apoE were present in the hemolymph of infected larvae. In contrast to apoE produced by recombinant baculovirus-infected insect cells in vitro, these particles were excellent ligands for the LDL receptor. Images PMID:1924311

  9. Zebrafish as a model for apolipoprotein biology: comprehensive expression analysis and a role for ApoA-IV in regulating food intake

    PubMed Central

    Otis, Jessica P.; Zeituni, Erin M.; Thierer, James H.; Anderson, Jennifer L.; Brown, Alexandria C.; Boehm, Erica D.; Cerchione, Derek M.; Ceasrine, Alexis M.; Avraham-Davidi, Inbal; Tempelhof, Hanoch; Yaniv, Karina; Farber, Steven A.

    2015-01-01

    Improved understanding of lipoproteins, particles that transport lipids throughout the circulation, is vital to developing new treatments for the dyslipidemias associated with metabolic syndrome. Apolipoproteins are a key component of lipoproteins. Apolipoproteins are proteins that structure lipoproteins and regulate lipid metabolism through control of cellular lipid exchange. Constraints of cell culture and mouse models mean that there is a need for a complementary model that can replicate the complex in vivo milieu that regulates apolipoprotein and lipoprotein biology. Here, we further establish the utility of the genetically tractable and optically clear larval zebrafish as a model of apolipoprotein biology. Gene ancestry analyses were implemented to determine the closest human orthologs of the zebrafish apolipoprotein A-I (apoA-I), apoB, apoE and apoA-IV genes and therefore ensure that they have been correctly named. Their expression patterns throughout development were also analyzed, by whole-mount mRNA in situ hybridization (ISH). The ISH results emphasized the importance of apolipoproteins in transporting yolk and dietary lipids: mRNA expression of all apolipoproteins was observed in the yolk syncytial layer, and intestinal and liver expression was observed from 4–6 days post-fertilization (dpf). Furthermore, real-time PCR confirmed that transcription of three of the four zebrafish apoA-IV genes was increased 4 hours after the onset of a 1-hour high-fat feed. Therefore, we tested the hypothesis that zebrafish ApoA-IV performs a conserved role to that in rat in the regulation of food intake by transiently overexpressing ApoA-IVb.1 in transgenic larvae and quantifying ingestion of co-fed fluorescently labeled fatty acid during a high-fat meal as an indicator of food intake. Indeed, ApoA-IVb.1 overexpression decreased food intake by approximately one-third. This study comprehensively describes the expression and function of eleven zebrafish apolipoproteins

  10. Cladistic analysis of human apolipoprotein a4 polymorphisms in relation to quantitative plasma lipid risk factors of coronary heart disease.

    PubMed

    Wang, G Q; DiPietro, M; Roeder, K; Heng, C-K; Bunker, C H; Hamman, R F; Kamboh, M I

    2003-03-01

    Genetic variation in several genes involved in lipid metabolism is known to affect population variation in quantitative lipid risk factor profiles for coronary heart disease (CHD). The apolipoprotein A-IV gene (APOA4) is one such candidate gene. We genotyped five polymorphisms in the APOA4 gene (codon 127, codon 130, codon347, codon 360 and 3' VNTR) and investigated their impact on plasma lipid trait levels in three populations comprising 604 U.S. non-Hispanic Whites (NHWs), 408 U.S. Hispanics and 708 Nigerian Blacks. Cladistic analysis was carried out to identify 5-site haplotypes that were associated with significant phenotypic differences in each population. The distribution of APOA4 genotypes was significantly different between ethnic groups. The Africans were monomorphic for two of the five sites (codons 130 and 360), but possess a unique 12 bp insertion that was not observed in NHWs and Hispanics. Due to linkage disequilibrium between the sites, only 6 haplotypes were observed in NHWs and Hispanics, and 4 in Africans. Several gender-and ethnic-specific associations between genotypes and plasma lipid traits were observed when single sites were used. Several haplotypes were identified by cladistic analysis that may carry functional mutations that affect plasma lipid trait levels.

  11. Sex-dependent modulation of longevity by two Drosophila homologues of human Apolipoprotein D, GLaz and NLaz.

    PubMed

    Ruiz, Mario; Sanchez, Diego; Canal, Inmaculada; Acebes, Angel; Ganfornina, Maria D

    2011-07-01

    Apolipoprotein D (ApoD), a member of the Lipocalin family, is the gene most up-regulated with age in the mammalian brain. Its expression strongly correlates with aging-associated neurodegenerative and metabolic diseases. Two homologues of ApoD expressed in the Drosophila brain, Glial Lazarillo (GLaz) and Neural Lazarillo (NLaz), are known to alter longevity in male flies. However, sex differences in the aging process have not been explored so far for these genes. Here we demonstrate that NLaz alters lifespan in both sexes, but unexpectedly the lack of GLaz influences longevity in a sex-specific way, reducing longevity in males but not in females. While NLaz has metabolic functions similar to ApoD, the regulation of GLaz expression upon aging is the closest to ApoD in the aging brain. A multivariate analysis of physiological parameters relevant to lifespan modulation uncovers both common and specialized functions for the two Lipocalins, and reveals that changes in protein homeostasis account for the observed sex-specific patterns of longevity. The response to oxidative stress and accumulation of lipid peroxides are among their common functions, while the transcriptional and behavioral response to starvation, the pattern of daily locomotor activity, storage of fat along aging, fertility, and courtship behavior differentiate NLaz from GLaz mutants. We also demonstrate that food composition is an important environmental parameter influencing stress resistance and reproductive phenotypes of both Lipocalin mutants. Since ApoD shares many properties with the common ancestor of invertebrate Lipocalins, we must benefit from this global comparison with both GLaz and NLaz to understand the complex functions of ApoD in mammalian aging and neurodegeneration.

  12. Human apolipoprotein E4 worsens acute axonal pathology but not amyloid-β immunoreactivity after traumatic brain injury in 3xTG-AD mice.

    PubMed

    Bennett, Rachel E; Esparza, Thomas J; Lewis, Hal A; Kim, Eddie; Mac Donald, Christine L; Sullivan, Patrick M; Brody, David L

    2013-05-01

    Apolipoprotein E4 (APOE4) genotype is a risk factor for poor outcome after traumatic brain injury (TBI), particularly in young patients, but the underlying mechanisms are not known. By analogy to effects of APOE4 on the risk of Alzheimer disease (AD), the APOE genotype may influence β-amyloid (Aβ) and tau deposition after TBI. To test this hypothesis, we crossed 3xTG-AD transgenic mice carrying 3 human familial AD mutations (PS1(M146V), tauP(301)L, and APP(SWE)) to human ApoE2-, ApoE3-, and ApoE4-targeted replacement mice. Six- to 8-month-old 3xTG-ApoE mice were assayed by quantitative immunohistochemistry for amyloid precursor protein (APP), Aβ(1-40) (Aβ40), Aβ(1-42) (Aβ42), total human tau, and phospho-serine 199 (pS199) tau at 24 hours after moderate controlled cortical impact. There were increased numbers of APP-immunoreactive axonal varicosities in 3xTG-ApoE4 mice versus the other genotypes. This finding was repeated in a separate cohort of ApoE4-targeted replacement mice without human transgenes compared with ApoE3 and ApoE2 mice. There were no differences between genotypes in the extent of intra-axonal Aβ40 and Aβ42; none of the mice had extracellular Aβ deposition. Regardless of injury status, 3xTG-ApoE4 mice had more total human tau accumulation in both somatodendritic and intra-axonal compartments than other genotypes. These results suggest that the APOE4 genotype may have a primary effect on the severity of axonal injury in acute TBI.

  13. AIS training manual

    SciTech Connect

    Kramer, C.F.; Barancik, J.I.

    1989-05-01

    This Training Manual was developed by the Injury Prevention and Analysis Group (IPAG) as part of a training program in AIS 85 and AIS-EM (Epidemiological Modifications) coding. The IPAG Program is designed primarily to train medical record and other health professionals from diverse backgrounds and experience levels in the use of AIS 85 and AIS 85-EM. The Manual is designed to be used as a reference text after completion of the Program and includes copies of visual projection materials used during the training sessions.

  14. Cross-species pharmacokinetic comparison from mouse to man of a second-generation antisense oligonucleotide, ISIS 301012, targeting human apolipoprotein B-100.

    PubMed

    Yu, Rosie Z; Kim, Tae-Won; Hong, An; Watanabe, Tanya A; Gaus, Hans J; Geary, Richard S

    2007-03-01

    The pharmacokinetics of a 2'-O-(2-methoxyethyl)-modified oligonucleotide, ISIS 301012 [targeting human apolipoprotein B-100 (apoB-100)], was characterized in mouse, rat, monkey, and human. Plasma pharmacokinetics following parental administration was similar across species, exhibiting a rapid distribution phase with t(1/2alpha) of several hours and a prolonged elimination phase with t(1/2beta) of days. The prolonged elimination phase represents equilibrium between tissues and circulating drug due to slow elimination from tissues. Absorption was nearly complete following s.c. injection, with bioavailability ranging from 80 to 100% in monkeys. Plasma clearance scaled well across species as a function of body weight alone, and this correlation was improved when corrected for plasma protein binding. In all of the animal models studied, the highest tissue concentrations of ISIS 301012 were observed in kidney and liver. Urinary excretion was less than 3% in monkeys and human in the first 24 h. ISIS 301012 is highly bound to plasma proteins, probably preventing rapid removal by renal filtration. However, following 25 mg/kg s.c. administration in mouse and 5-mg/kg i.v. bolus administration in rat, plasma concentrations of ISIS 301012 exceeded their respective protein binding capacity. Thus, urinary excretion increased to 16% or greater within the first 24 h. Albeit slow, urinary excretion of ISIS 301012 and its shortened metabolites is the ultimate elimination pathway of this compound, as demonstrated by 32% of dose recovered in total excreta by 14 days in a rat mass balance study. The pharmacokinetics of ISIS 301012 in human is predictable from the pharmacokinetics measured in animals. The pharmacokinetic properties of ISIS 301012 provide guidance for clinical development and support infrequent dose administration.

  15. Independent effects of apolipoprotein AV and apolipoprotein CIII on plasma triglyceride concentrations

    SciTech Connect

    Baroukh, Nadine N.; Bauge, Eric; Akiyama, Jennifer; Chang, Jessie; Fruchart, Jean-Charles; Rubin, Edward M.; Fruchart, Jamila; Pennacchio, Len A.

    2003-08-15

    Both the apolipoprotein A5 and C3 genes have repeatedly been shown to play an important role in determining plasma triglyceride concentrations in humans and mice. In mice, transgenic and knockout experiments indicate that plasma triglyceride levels are negatively and positively correlated with APOA5 and APOC3 expression, respectively. In humans, common polymorphisms in both genes have also been associated with plasma triglyceride concentrations. The evolutionary relationship among these two apolipoprotein genes and their close proximity on human chromosome 11q23 have largely precluded the determination of their relative contribution to altered Both the apolipoprotein A5 and C3 genes have repeatedly been shown to play an important role in determining plasma triglyceride concentrations in humans and mice. In mice, transgenic and knockout experiments indicate that plasma triglyceride levels are negatively and positively correlated with APOA5 and APOC3 expression, respectively. In humans, common polymorphisms in both genes have also been associated with plasma triglyceride concentrations. The evolutionary relationship among these two apolipoprotein genes and their close proximity on human chromosome 11q23 have largely precluded the determination of their relative contribution to altered triglycerides. To overcome these confounding factors and address their relationship, we generated independent lines of mice that either over-expressed (''double transgenic'') or completely lacked (''double knockout'') both apolipoprotein genes. We report that both ''double transgenic'' and ''double knockout'' mice display intermedia tetriglyceride concentrations compared to over-expression or deletion of either gene alone. Furthermore, we find that human ApoAV plasma protein levels in the ''double transgenic'' mice are approximately 500-fold lower than human ApoCIII levels, supporting ApoAV is a potent triglyceride modulator despite its low concentration. Together, these data indicate

  16. Molecular basis of a unique African variant (A-IV 5) of human apolipoprotein A-IV and its significance in lipid metabolism.

    PubMed

    Kamboh, M I; Williams, E R; Law, J C; Aston, C E; Bunker, C H; Ferrell, R E; Pollitzer, W S

    1992-01-01

    Human apolipoprotein A-IV (apoA-IV) exhibits a genetically determined structural polymorphism amenable to analysis by isoelectric focusing and immunoblotting techniques. We have determined the allele frequency and molecular basis of a unique ApoA-IV*5 allele which is widely distributed among blacks but is absent in other populations. The frequency of the ApoA-IV*5 allele in blacks (N = 308) was estimated to be 3.2%. In comparison to the common ApoA-IV*1 allele, analysis of coding and non-coding sequences of the ApoA-IV*5 allele revealed an in-frame insertion of 12 nucleotides near the carboxyl terminal region of the mature protein. The insertion involves an exact duplication of the second of the four repeats and codes for 4 amino acids glutamic acid (GAA), glutamine (CAG), glutamine (CAG), and glutamine (CAG) and is responsible for the charge shift of the the apoA-IV 5 isoform slightly toward the anode as compared to the wild type apoA-IV 1 isoform on the isoelectric focusing gel. This in-frame insertion occurs in a region which is highly conserved among rat, mouse, and humans. In addition to the 12 nucleotide insertion, the four individuals sequenced for the ApoA-IV*5 allele also revealed a same-sense mutation by replacing G to T at the third position of codon 316. Our preliminary data suggest that this unique black allele marker may be of potentially significance in studies of human lipid metabolism and in microevolution.

  17. Phenotypes of apolipoprotein B and apolipoprotein E after liver transplantation.

    PubMed Central

    Linton, M F; Gish, R; Hubl, S T; Bütler, E; Esquivel, C; Bry, W I; Boyles, J K; Wardell, M R; Young, S G

    1991-01-01

    Apolipoprotein (apo) E and the two B apolipoproteins, apoB48 and apoB100, are important proteins in human lipoprotein metabolism. Commonly occurring polymorphisms in the genes for apoE and apoB result in amino acid substitutions that produce readily detectable phenotypic differences in these proteins. We studied changes in apoE and apoB phenotypes before and after liver transplantation to gain new insights into apolipoprotein physiology. In all 29 patients that we studied, the postoperative serum apoE phenotype of the recipient, as assessed by isoelectric focusing, converted virtually completely to that of the donor, providing evidence that greater than 90% of the apoE in the plasma is synthesized by the liver. In contrast, the cerebrospinal fluid apoE phenotype did not change to the donor's phenotype after liver transplantation, indicating that most of the apoE in CSF cannot be derived from the plasma pool and therefore must be synthesized locally. The apoB100 phenotype (assessed with immunoassays using monoclonal antibody MB19, an antibody that detects a two-allele polymorphism in apoB) invariably converted to the phenotype of the donor. In four normolipidemic patients, we determined the MB19 phenotype of both the apoB100 and apoB48 in the "chylomicron fraction" isolated from plasma 3 h after a fat-rich meal. Interestingly, the apoB100 in the chylomicron fraction invariably had the phenotype of the donor, indicating that the vast majority of the large, triglyceride-rich apoB100-containing lipoproteins that appear in the plasma after a fat-rich meal are actually VLDL of hepatic origin. The MB19 phenotype of the apoB48 in the plasma chylomicron fraction did not change after liver transplantation, indicating that almost all of the apoB48 in plasma chylomicrons is derived from the intestine. These results were consistent with our immunocytochemical studies on intestinal biopsy specimens of organ donors; using apoB-specific monoclonal antibodies, we found evidence for

  18. Human apolipoprotein E4 modulates the expression of Pin1, Sirtuin 1, and Presenilin 1 in brain regions of targeted replacement apoE mice.

    PubMed

    Lattanzio, F; Carboni, L; Carretta, D; Rimondini, R; Candeletti, S; Romualdi, P

    2014-01-01

    The apolipoprotein E4 (apoE4) allele is consistently associated with increased risk for Alzheimer's disease (AD). We investigated the molecular mechanism of this susceptibility by analyzing the levels of genes involved in AD pathogenesis in transgenic mice expressing human apoE3 or apoE4 isoforms. mRNA and protein levels of Pin1, Sirtuin 1 (Sirt1), Presenilin 1 (PS1), and pro-Brain-derived Neurotrophic Factor (BDNF) were analyzed in brain regions affected by neuropathological changes in AD. Pin1 mRNA was significantly higher in the hippocampus of apoE4 mice than in apoE3 controls, whereas lower expression was detected in the entorhinal and parietal cortices. Reduced Pin1 levels may increase neurofibrillary degeneration and amyloidogenic processes, while compensatory mechanisms may take place in the hippocampus to balance spatial memory deficits. Sirt1 levels were significantly reduced in the frontal cortex of apoE4 mice. Sirt1 reduction may hinder its protective role against the formation of plaques and tangles and diminish its anti-inflammatory actions. Sirt1 decrease may also play a role in apoE4-associated memory impairments. Moreover, in apoE4 mice PS1 mRNA levels were lower in the frontal cortex. Lower PS1 expression may hamper γ-secretase function, thus affecting amyloid precursor protein processing. Pro-BDNF mRNA levels did not differ between apoE3 and apoE4 mice in any region analyzed. This study showed dysregulated expression of Pin1, Sirt1, and PS1 genes in different cerebral areas of apoE4 mice, suggesting that these changes may play a role in the mechanism of AD vulnerability.

  19. Apolipoprotein 4 may increase viral load and seizure frequency in mesial temporal lobe epilepsy patients with positive human herpes virus 6B.

    PubMed

    Huang, Cheng; Yan, Bo; Lei, Ding; Si, Yang; Li, He; Chen, Ming-Wan; Li, Li; Chen, Fei; Zhou, Qiao; Zhou, Dong; Li, Jin-Mei

    2015-04-23

    This study investigated whether apolipoprotein 4 (ApoE4) was associated with the presence of human herpes virus (HHV)-6B in mesial temporal lobe epilepsy (MTLE). Polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) was used to determine ApoE polymorphism in 46 patients with MTLE and 19 controls. Nested PCR and real-time PCR were applied to determine HHV-6B DNA and immunohistochemistry (IHC) for HHV-6B protein. Viral DNA load was significantly increased in MTLE patients with HHV-6B(+)/ApoE4 compared with those with HHV-6B(+)/non-ApoE4 (p=0.031). Semi-quantitative analysis of IHC showed significantly increased number of positive cells for HHV-6B proteins G116/64/54, P98 and U94 in patients with HHV-6B(+)/ApoE4 than HHV-6B(+)/non-ApoE4 (p=0.009, 0.035 and 0.009, respectively). Patients with HHV-6B(+)/ApoE4 showed higher seizure frequency than those with HHV-6B(+)/non-ApoE4 (p=0.005). There was no significant difference of ApoE alleles between MTLE with and without HHV-6B (p=0.115). ApoE4 was not associated with initial infection of HHV-6B in MTLE. However, ApoE4 may facilitate HHV-6B reactivation, DNA replication, virus protein expression and increase seizure frequency in MTLE. Further investigations are needed to understand the biomolecular mechanism underlying interaction between ApoE and HHV-6B.

  20. Lysine-phosphatidylcholine adducts in kringle V impart unique immunological and potential pro-inflammatory properties to human apolipoprotein(a).

    PubMed

    Edelstein, Celina; Pfaffinger, Ditta; Hinman, Janet; Miller, Elizabeth; Lipkind, Gregory; Tsimikas, Sotirios; Bergmark, Claes; Getz, Godfrey S; Witztum, Joseph L; Scanu, Angelo M

    2003-12-26

    Lipoprotein(a), Lp(a), an athero-thrombotic risk factor, reacts with EO6, a natural monoclonal autoantibody that recognizes the phophorylcholine (PC) group of oxidized phosphatidylcholine (oxPtdPC) either as a lipid or linked by a Schiff base to lysine residues of peptides/proteins. Here we show that EO6 reacts with free apolipoprotein(a) apo(a), its C-terminal domain, F2 (but not the N-terminal F1), kringle V-containing fragments obtained by the enzymatic digestion of apo(a) and also kringle V-containing apo(a) recombinants. The evidence that kringle V is critical for EO6 reactivity is supported by the finding that apo(a) of rhesus monkeys lacking kringle V did not react with EO6. Based on the previously established EO6 specificity requirements, we hypothesized that all or some of the six lysines in human kringle V are involved in Schiff base linkage with oxPtdPC. To test this hypothesis, we made use of a recombinant lysine-containing apo(a) fragment, rIII, containing kringle V but not the protease domain. EO6 reacted with rIII before and after reduction to stabilize the Schiff base and also after extensive ethanol/ether extraction that yielded no lipids. On the other hand, delipidation of the saponified product yielded an average of two mol of phospholipids/mol of protein consistent with direct analysis of inorganic phosphorous on the non-saponified rIII. Moreover, only two of the six theoretical free lysine amino groups per mol of rIII were unavailable to chemical modification by 2,4,6-trinitrobenzene sulfonic acid. Finally, rIII, like human apo(a), stimulated the production of interleukin 8 in THP-1 macrophages in culture. Together, our studies provide evidence that in human apo(a), kringle V is the site that reacts with EO6 via lysine-oxPtdPC adducts that may also be involved in the previously reported pro-inflammatory effect of apo(a) in cultured human macrophages. PMID:14557258

  1. Artificial intelligence. Fears of an AI pioneer.

    PubMed

    Russell, Stuart; Bohannon, John

    2015-07-17

    From the enraged robots in the 1920 play R.U.R. to the homicidal computer H.A.L. in 2001: A Space Odyssey, science fiction writers have embraced the dark side of artificial intelligence (AI) ever since the concept entered our collective imagination. Sluggish progress in AI research, especially during the “AI winter” of the 1970s and 1980s, made such worries seem far-fetched. But recent breakthroughs in machine learning and vast improvements in computational power have brought a flood of research funding— and fresh concerns about where AI may lead us. One researcher now speaking up is Stuart Russell, a computer scientist at the University of California, Berkeley, who with Peter Norvig, director of research at Google, wrote the premier AI textbook, Artificial Intelligence: A Modern Approach, now in its third edition. Last year, Russell joined the Centre for the Study of Existential Risk at Cambridge University in the United Kingdom as an AI expert focusing on “risks that could lead to human extinction.” Among his chief concerns, which he aired at an April meeting in Geneva, Switzerland, run by the United Nations, is the danger of putting military drones and weaponry under the full control of AI systems. This interview has been edited for clarity and brevity.

  2. Artificial intelligence. Fears of an AI pioneer.

    PubMed

    Russell, Stuart; Bohannon, John

    2015-07-17

    From the enraged robots in the 1920 play R.U.R. to the homicidal computer H.A.L. in 2001: A Space Odyssey, science fiction writers have embraced the dark side of artificial intelligence (AI) ever since the concept entered our collective imagination. Sluggish progress in AI research, especially during the “AI winter” of the 1970s and 1980s, made such worries seem far-fetched. But recent breakthroughs in machine learning and vast improvements in computational power have brought a flood of research funding— and fresh concerns about where AI may lead us. One researcher now speaking up is Stuart Russell, a computer scientist at the University of California, Berkeley, who with Peter Norvig, director of research at Google, wrote the premier AI textbook, Artificial Intelligence: A Modern Approach, now in its third edition. Last year, Russell joined the Centre for the Study of Existential Risk at Cambridge University in the United Kingdom as an AI expert focusing on “risks that could lead to human extinction.” Among his chief concerns, which he aired at an April meeting in Geneva, Switzerland, run by the United Nations, is the danger of putting military drones and weaponry under the full control of AI systems. This interview has been edited for clarity and brevity. PMID:26185241

  3. Black knight of AI

    SciTech Connect

    Rose, F.

    1985-03-01

    For two decades now, Hubert Dreyfus, an existentialist philosopher at the University of California at Berkeley, has been in the forefront of the controversy over artificial intelligence. He maintains that computers will never be able to think because scientists will never come up with a suitably rigorous set of rules to describe how we think. To many computer scientists, this is like saying the Earth is flat. But so far, none of them have been able to prove him wrong. Even most AI researchers now admit that before they can make computers any smarter, they'll have to come up with an explanation of how intelligence works in people. This realization has coincided with the emergence of cognitive science, a new discipline linking philosophy, psychology, anthroplogy, linguistics, neuroscience, and computer science in an attempt to develop a theory of the way humans think. The guiding principle of most cognitive science research is the notion that the mind, like the computer, is a system for manipulating symbols - for processing information. The task of cognitive science is to discover how this processing occurs.

  4. The complete sequence and structural analysis of human apolipoprotein B-100: relationship between apoB-100 and apoB-48 forms.

    PubMed Central

    Cladaras, C; Hadzopoulou-Cladaras, M; Nolte, R T; Atkinson, D; Zannis, V I

    1986-01-01

    We have isolated and sequenced overlapping cDNA clones covering the entire sequence of human apolipoprotein B-100 (apoB-100). DNA sequence analysis and determination of the mRNA transcription initiation site by S1 nuclease mapping showed that the apoB mRNA consists of 14,112 nucleotides including the 5' and 3' untranslated regions which are 128 and 301 nucleotides respectively. The DNA-derived protein sequence shows that apoB-100 is 513,000 daltons and contains 4560 amino acids including a 24-amino-acid-long signal peptide. The mol. wt of apoB-100 implies that there is one apoB molecule per LDL particle. Computer analysis of the predicted secondary structure of the protein showed that some of the potential alpha helical and beta sheet structures are amphipathic, whereas others have non-amphipathic neutral to apolar character. These latter regions may contribute to the formation of the lipid-binding domains of apoB-100. The protein contains 25 cysteines and 20 potential N-glycosylation sites. The majority of cysteines are distributed in the amino terminal portion of the protein. Four of the potential glycosylation sites are in predicted beta turn structures and may represent true glycosylation positions. ApoB lacks the tandem repeats which are characteristic of other apolipoproteins. The mean hydrophobicity the mean value of H1 and helical hydrophobic moment the mean value of microH profiles of apoB showed the presence of several potential helical regions with strong polar character and high hydrophobic moment. The region with the highest hydrophobic moment, between amino acid residues 3352 and 3369, contains five closely spaced, positively charged residues, and has sequence homology to the LDL receptor binding site of apoE. This region is flanked by three neighbouring regions with positively charged amino acids and high hydrophobic moment that are located between residues 3174 and 3681. One or more of these closely spaced apoB sequences may be involved in the

  5. Cerebral Apolipoprotein-D Is Hypoglycosylated Compared to Peripheral Tissues and Is Variably Expressed in Mouse and Human Brain Regions

    PubMed Central

    Li, Hongyun; Ruberu, Kalani; Karl, Tim; Garner, Brett

    2016-01-01

    Recent studies have shown that cerebral apoD levels increase with age and in Alzheimer’s disease (AD). In addition, loss of cerebral apoD in the mouse increases sensitivity to lipid peroxidation and accelerates AD pathology. Very little data are available, however, regarding the expression of apoD protein levels in different brain regions. This is important as both brain lipid peroxidation and neurodegeneration occur in a region-specific manner. Here we addressed this using western blotting of seven different regions (olfactory bulb, hippocampus, frontal cortex, striatum, cerebellum, thalamus and brain stem) of the mouse brain. Our data indicate that compared to most brain regions, the hippocampus is deficient in apoD. In comparison to other major organs and tissues (liver, spleen, kidney, adrenal gland, heart and skeletal muscle), brain apoD was approximately 10-fold higher (corrected for total protein levels). Our analysis also revealed that brain apoD was present at a lower apparent molecular weight than tissue and plasma apoD. Utilising peptide N-glycosidase-F and neuraminidase to remove N-glycans and sialic acids, respectively, we found that N-glycan composition (but not sialylation alone) were responsible for this reduction in molecular weight. We extended the studies to an analysis of human brain regions (hippocampus, frontal cortex, temporal cortex and cerebellum) where we found that the hippocampus had the lowest levels of apoD. We also confirmed that human brain apoD was present at a lower molecular weight than in plasma. In conclusion, we demonstrate apoD protein levels are variable across different brain regions, that apoD levels are much higher in the brain compared to other tissues and organs, and that cerebral apoD has a lower molecular weight than peripheral apoD; a phenomenon that is due to the N-glycan content of the protein. PMID:26829325

  6. Human apolipoprotein E4 targeted replacement in mice reveals increased susceptibility to sleep disruption and intermittent hypoxia

    PubMed Central

    Kaushal, Navita; Ramesh, Vijay

    2012-01-01

    Intermittent hypoxia (IH) and sleep fragmentation (SF) are major manifestations of sleep apnea, a frequent condition in aging humans. Sleep perturbations are frequent in Alzheimer's disease (AD) and may underlie the progression of disease. We hypothesized that acute short-term IH, SF, and their combination (IH+SF) may reveal unique susceptibility in sleep integrity in a murine model of AD. The effects of acute IH, SF, and IH+SF on sleep architecture, delta power, sleep latency, and core body temperature were assessed in adult male human ApoE4-targeted replacement mice (hApoE4) and wild-type (WT) controls. Slow wave sleep (SWS) was significantly reduced, and rapid eye movement (REM) sleep was almost abolished during acute exposure to IH alone and IH+SF for 6 h in hApoE4, with milder effects in WT controls. Decreased delta power during SWS did not show postexposure rebound in hApoE4 unlike WT controls. IH and IH+SF induced hypothermia, which was more prominent in hApoE4 than WT controls. Mice subjected to SF also showed sleep deficits but without hypothermia. hApoE4 mice, unlike WT controls, exhibited increased sleep propensity, especially following IH and IH+SF, suggesting limited ability for sleep recovery in hApoE4 mice. These findings substantiate the potential impact of IH and SF in modulating sleep architecture and sleep homeostasis including maintenance of body temperature. Furthermore, the increased susceptibility and limited recovery ability of hApoE4 mice to sleep apnea suggests that early recognition and treatment of the latter in AD patients may restrict the progression and clinical manifestations of this frequent neurodegenerative disorder. PMID:22573105

  7. Targeting nanodisks via a single chain variable antibody--apolipoprotein chimera.

    PubMed

    Iovannisci, David M; Beckstead, Jennifer A; Ryan, Robert O

    2009-02-01

    Nanodisks (ND) are nanometer scale complexes of phospholipid and apolipoprotein that have been shown to function as drug delivery vehicles. ND harboring significant quantities of the antifungal agent, amphotericin B, or the bioactive isoprenoid, all trans retinoic acid, have been generated and characterized. As currently formulated, ND possess limited targeting capability. In this study, we constructed a single chain variable antibody (scFv).apolipoprotein chimera and assessed the ability of this fusion protein to form ND and recognize the antigen to which the scFv is directed. Data obtained revealed that alpha-vimentin scFv.apolipoprotein A-I is functional in ND formation and antigen recognition, opening the door to the use of such chimeras in targeting drug-enriched ND to specific tissues.

  8. Apolipoprotein gene polymorphisms and plasma levels in healthy Tunisians and patients with coronary artery disease

    PubMed Central

    Bahri, Raoudha; Esteban, Esther; Moral, Pedro; Hassine, Mohsen; Hamda, Khaldoun Ben; Chaabani, Hassen

    2008-01-01

    Aim To analyze apolipoprotein gene polymorphisms in the Tunisian population and to check the relation of these polymorphisms and homocysteine, lipid and apolipoprotein levels to the coronary artery disease (CAD). Methods In healthy blood donors and in patients with CAD complicated by myocardial infarction (MI) four apolipoprotein gene polymorphisms [APO (a) PNR, APO E, APO CI and APO CII] were determined and plasma levels of total homocysteine, total cholesterol (TC), triglycerides (TG), HDL-cholesterol (HLD-C) and apolipoproteins (apo A-I, Apo B, Apo E) were measured. Results Analysis of the four apolipoprotein gene polymorphisms shows a relative genetic homogeneity between Tunisian population and those on the other side of Mediterranean basin. Compared to controls, CAD patients have significantly higher main concentrations of TC, TG, LDL-C, apo B and homocysteine, and significantly lower ones of HDL-C, apo A-I and apo E. The four apolipoprotein gene polymorphisms have not showed any significant differences between patients and controls. However, the APO E4 allele appears to be associated to the severity of CAD and to high levels of atherogenic parameters and low level of apo E, which has very likely an anti-atherogenic role. Conclusion Although APO (a) PNR, APO CI and APO CII genes are analyzed in only few populations, they show a frequency distribution, which is not at variance with that of APO E gene and other widely studied genetic markers. In the Tunisian population the APO E 4 appears to be only indirectly involved in the severity of CAD. In the routine practice, in addition of classic parameters, it will be useful to measure the concentration of apo E and that of Homocysteine and if possible to determine the APO E gene polymorphism. PMID:19014618

  9. Apolipoprotein E Isoforms and AMD.

    PubMed

    Toops, Kimberly A; Tan, Li Xuan; Lakkaraju, Aparna

    2016-01-01

    The cholesterol transporting protein apolipoprotein E (ApoE) occurs in three allelic variants in humans unlike in other species. The resulting protein isoforms E2, E3 and E4 exhibit differences in lipid binding, integrating into lipoprotein particles and affinity for lipoprotein receptors. ApoE isoforms confer genetic risk for several diseases of aging including atherosclerosis, Alzheimer's disease, and age-related macular degeneration (AMD). A single E4 allele increases the risk of developing Alzheimer's disease, whereas the E2 allele is protective. Intriguingly, the E4 allele is protective in AMD. Current thinking about different functions of ApoE isoforms comes largely from studies on Alzheimer's disease. These data cannot be directly extrapolated to AMD since the primary cells affected in these diseases (neurons vs. retinal pigment epithelium) are so different. Here, we propose that ApoE serves a fundamentally different purpose in regulating cholesterol homeostasis in the retinal pigment epithelium and this could explain why allelic risk factors are flipped for AMD compared to Alzheimer's disease.

  10. The structure of human apolipoprotein A-IV as revealed by stable isotope-assisted cross-linking, molecular dynamics, and small angle x-ray scattering.

    PubMed

    Walker, Ryan G; Deng, Xiaodi; Melchior, John T; Morris, Jamie; Tso, Patrick; Jones, Martin K; Segrest, Jere P; Thompson, Thomas B; Davidson, W Sean

    2014-02-28

    Apolipoprotein (apo)A-IV plays important roles in dietary lipid and glucose metabolism, and knowledge of its structure is required to fully understand the molecular basis of these functions. However, typical of the entire class of exchangeable apolipoproteins, its dynamic nature and affinity for lipid has posed challenges to traditional high resolution structural approaches. We previously reported an x-ray crystal structure of a dimeric truncation mutant of apoA-IV, which showed a unique helix-swapping molecular interface. Unfortunately, the structures of the N and C termini that are important for lipid binding were not visualized. To build a more complete model, we used chemical cross-linking to derive distance constraints across the full-length protein. The approach was enhanced with stable isotope labeling to overcome ambiguities in determining molecular span of the cross-links given the remarkable similarities in the monomeric and dimeric apoA-IV structures. Using 51 distance constraints, we created a starting model for full-length monomeric apoA-IV and then subjected it to two modeling approaches: (i) molecular dynamics simulations and (ii) fitting to small angle x-ray scattering data. This resulted in the most detailed models yet for lipid-free monomeric or dimeric apoA-IV. Importantly, these models were of sufficient detail to direct the experimental identification of new functional residues that participate in a "clasp" mechanism to modulate apoA-IV lipid affinity. The isotope-assisted cross-linking approach should prove useful for further study of this family of apolipoproteins in both the lipid-free and -bound states. PMID:24425874

  11. AI in manufacturing

    NASA Astrophysics Data System (ADS)

    Gross, John E.; Minato, Rick; Smith, David M.; Loftin, R. B.; Savely, Robert T.

    1991-10-01

    AI techniques are shown to have been useful in such aerospace industry tasks as vehicle configuration layouts, process planning, tool design, numerically-controlled programming of tools, production scheduling, and equipment testing and diagnosis. Accounts are given of illustrative experiences at the production facilities of three major aerospace defense contractors. Also discussed is NASA's autonomous Intelligent Computer-Aided Training System, for such ambitious manned programs as Space Station Freedom, which employs five different modules to constitute its job-independent training architecture.

  12. Familial apolipoprotein E deficiency.

    PubMed Central

    Schaefer, E J; Gregg, R E; Ghiselli, G; Forte, T M; Ordovas, J M; Zech, L A; Brewer, H B

    1986-01-01

    A unique kindred with premature cardiovascular disease, tubo-eruptive xanthomas, and type III hyperlipoproteinemia (HLP) associated with familial apolipoprotein (apo) E deficiency was examined. Homozygotes (n = 4) had marked increases in cholesterol-rich very low density lipoproteins (VLDL) and intermediate density lipoproteins (IDL), which could be effectively lowered with diet and medication (niacin, clofibrate). Homozygotes had only trace amounts of plasma apoE, and accumulations of apoB-48 and apoA-IV in VLDL, IDL, and low density lipoproteins. Radioiodinated VLDL apoB and apoE kinetic studies revealed that the homozygous proband had markedly retarded fractional catabolism of VLDL apoB-100, apoB-48 and plasma apoE, as well as an extremely low apoE synthesis rate as compared to normals. Obligate heterozygotes (n = 10) generally had normal plasma lipids and mean plasma apoE concentrations that were 42% of normal. The data indicate that homozygous familial apoE deficiency is a cause of type III HLP, is associated with markedly decreased apoE production, and that apoE is essential for the normal catabolism of triglyceride-rich lipoprotein constituents. Images PMID:3771793

  13. Pro-apoptotic activities of polyphenolics from açai (Euterpe oleracea Martius) in human SW-480 colon cancer cells.

    PubMed

    Dias, Manoela Maciel dos Santos; Noratto, Giuliana; Martino, Hercia Stampini Duarte; Arbizu, Shirley; Peluzio, Maria do Carmo Gouveia; Talcott, Stephen; Ramos, Afonso Mota; Mertens-Talcott, Susanne U

    2014-01-01

    This study aimed to evaluate the cell growth inhibition activity of açai (Euterpe oleracea Mart.) polyphenolic extract against colon cancer HT-29 and SW-480 cells and the nonmalignant CCD-18Co colon fibroblast cells. Results showed that açai polyphenolic extract (5-20 mg/L) inhibited preferentially the growth of SW-480 cells with no toxicity in CCD-18Co cells, and this was accompanied by reduction of H2O2-induced reactive oxygen species (ROS) generation. The mechanisms involved in SW-480 cell growth-inhibition by açai polyphenolic extract included the downregulation of NF-κB proinflammatory transcription factor and the nuclear factor-kappa B targets intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). Furthermore, prooncogenic specificity proteins (Sp) were downregulated as well as Sp-targets Bcl-2, vascular endothelial growth factor, and survivin. This was accompanied by activation of mitochondrial proapoptotic pathway involving increase of cytochrome c, cleavage of caspase-3, and decrease of PARP-1. Results strongly suggest that açai polyphenolic extract has antiinflammatory and cytotoxic activities in colon cancer cells and can be effective as natural colon cancer chemopreventive agents. PMID:25329001

  14. Apolipoprotein A-IV protein polymorphism: frequency and effects on lipids, lipoproteins, and apolipoproteins among Mexican-Americans in Starr County, Texas.

    PubMed

    Hanis, C L; Douglas, T C; Hewett-Emmett, D

    1991-01-01

    Apolipoprotein A-IV phenotypes were determined by reprobing immunoblots initially typed for the apolipoprotein E polymorphism on a representative sample of Mexican-Americans from South Texas. Typings on 331 individuals gave frequency estimates of 0.928, 0.066, 0.003, and 0.003 for alleles 1, 2, 3, and 4, respectively. To evaluate the effects of this polymorphic variability on lipid-related measures, mean levels between phenotypes were tested for equality following adjustment for age, sex, and body mass index. Analyses of levels of cholesterol, triglycerides, total high density lipoprotein, and its subfractions, low density lipoprotein, alpha and beta lipoproteins and apolipoproteins A-I, A-II, B, C-II, C-III, and E demonstrate that the A-IV genetic variability contributes minimally to normal variation of these quantitative factors in the population. Examination of the rare types, however, indicates the possibility of large metabolic effects whose follow-up may be useful for elucidating the metabolic roles of apolipoprotein A-IV. PMID:1997391

  15. Plasma lipid, lipoprotein and apolipoprotein profiles in Nigerian university athletes and non-athletes.

    PubMed Central

    Oyelola, O O; Rufai, M A

    1993-01-01

    The fasting plasma lipid, lipoprotein and apolipoprotein profiles were determined in 14 healthy Nigerian male athletes and controls matched for sex and anthropometric parameters. The mean levels of total cholesterol (P < 0.05), low-density lipoprotein (LDL) cholesterol, apolipoprotein (apo) AII and E were significantly lower (P < 0.01) in the athletes than in the controls. However, there were no statistically significant differences (P > 0.05) between the mean values of the plasma triglycerides, high-density lipoprotein (HDL), very low-density lipoprotein (VLDL) cholesterol, apo AI, B, Lp(a), LpA1 and CIII:NonB respectively for the athletes and controls. A priori, the potential effect on cardiovascular disease (CVD) risk was also compared using three predictor ratios - total cholesterol: HDL cholesterol (TC:HDL), LDL cholesterol: HDL cholesterol and apo B:AI. The mean of the three ratios was lower in the athletes than in the controls; however, the differences were not statistically significant (P > 0.05). Based on our data, exercise appears to decrease the TC:HDL ratio in the athletes by lowering LDL-cholesterol, while the HDL-cholesterol is unaffected. We conclude that physical activity has salutary effects on the lipid, lipoprotein and apolipoprotein profiles of healthy Nigerian men. PMID:8130968

  16. Apolipoprotein E genotype in schizophrenia

    SciTech Connect

    Joober, R.; Lal, S.; Bloom, D.; Benkelfat, C.

    1996-04-09

    We investigated the association between schizophrenia and the allelic polymorphism in the apolipoprotein E (Apo E) gene in 51 schizophrenic patients and 35 controls. The Apo E4 allele was equally represented in the schizophrenic group (16%) and the control group (20%) suggesting no association between schizophrenia and the Apo E4 allele. The apolipoprotein E (Apo E) is a polymorphic (E2, E3, and E4) lipoprotein involved in the transmembrane transport of cholesterol and is thought to play an important role in neuronal growth and in the central nervous system response to injury, particularly in the hippocampal region. Recent findings strongly suggest that the Apo E4 allele is associated with cognitive deficits in normal and pathological aging, e.g., Alzheimer`s disease. 5 refs., 1 tab.

  17. Multivitamin supplementation of adult omnivores and lactovegetarians: circulating levels of vitamin A, D and E, lipids, apolipoproteins and selenium.

    PubMed

    Kumpusalo, E; Karinpää, A; Jauhiainen, M; Laitinen, M; Lappeteläinen, R; Mäenpää, P H

    1990-01-01

    Serum levels of fat-soluble vitamins, lipids, apolipoproteins, total protein, hemoglobin, iron, and selenium were determined in healthy Finnish adults during a 7-month period beginning in January and ending in August. The subjects were either omnivores or established lactovegetarians, who had consumed their respective diets for at least 6 months prior to the study. Half of the subjects in both groups received daily multivitamin supplementation and the other half served as controls. In the beginning, the lactovegetarians differed from the omnivores in having lower serum levels of protein, apolipoproteins A-I and C-II, and higher levels of standardized alpha-tocopherol. During the study, serum retinol and standardized alpha-tocopherol (in March and May), as well as apolipoproteins A-I and C-II, and selenium decreased in the omnivores and 25-hydroxyvitamin D2, 25-hydroxyvitamin D3, cholesterol, HDL-cholesterol, and the HDL-cholesterol/cholesterol ratio increased. Apolipoprotein B decreased and then increased. In the lactovegetarians, serum selenium and protein decreased during the study, whereas retinol and alpha-tocopherol stayed higher than in the omnivores. Consumption of the lactovegetarian diet was accompanied by lower circulating levels of cholesterol and selenium and higher levels of retinol and standardized alpha-tocopherol than the mixed diet. Multivitamin supplementation may have value especially for omnivores in northern countries, like Finland, in providing better retinol, alpha-tocopherol, vitamin D, and selenium status in late winter and early spring.

  18. Relationships between the responses of triglyceride-rich lipoproteins in blood plasma containing apolipoproteins B-48 and B-100 to a fat-containing meal in normolipidemic humans.

    PubMed Central

    Schneeman, B O; Kotite, L; Todd, K M; Havel, R J

    1993-01-01

    The concentration of triglyceride-rich lipoproteins containing apolipoprotein (apo) B-48 (chylomicrons) and apo B-100 (very low density lipoproteins) was measured in blood plasma of healthy young men after an ordinary meal containing one-third of daily energy and fat. Plasma obtained in the postabsorptive state and at intervals up to 12 hr after the meal was subjected to immunoaffinity chromatography against a monoclonal antibody to apo B-100 that does not bind apo B-48 and a minor fraction of apo B-100 rich in apo E. Measurements of the concentrations of components of the total and unbound triglyceride-rich lipoproteins separated from plasma by ultracentrifugation showed that about 80% of the increase in lipoprotein particle number was in very low density lipoproteins containing apo B-100 and only 20% was in chylomicrons containing apo B-48 that carry dietary fat from the intestine. The maximal increments and the average concentrations of apo B-48 and B-100 during the 12 hr were highly correlated (r2 = 0.80), suggesting that preferential clearance of chylomicron triglycerides by lipoprotein lipase leads to accumulation of hepatogenous very low density lipoproteins during the alimentary period. The composition of the bulk of very low density lipoproteins that were bound to the monoclonal antibody changed little and these particles contained about 90% of the cholesterol and most of the apo E that accumulated in triglyceride-rich lipoproteins. The predominant accumulation of very low density lipoprotein rather than chylomicron particles after ingestion of ordinary meals is relevant to the potential atherogenicity of postprandial lipoproteins. PMID:8446630

  19. Identification of the human ApoAV gene as a novel ROR{alpha} target gene

    SciTech Connect

    Lind, Ulrika; Nilsson, Tina; McPheat, Jane; Stroemstedt, Per-Erik; Bamberg, Krister; Balendran, Clare; Kang, Daiwu . E-mail: Daiwu.Kang@astrazeneca.com

    2005-04-29

    Retinoic acid receptor-related orphan receptor-{alpha} (ROR{alpha}) (NR1F1) is an orphan nuclear receptor with a potential role in metabolism. Previous studies have shown that ROR{alpha} regulates transcription of the murine Apolipoprotein AI gene and human Apolipoprotein CIII genes. In the present study, we present evidence that ROR{alpha} also induces transcription of the human Apolipoprotein AV gene, a recently identified apolipoprotein associated with triglyceride levels. Adenovirus-mediated overexpression of ROR{alpha} increased the endogenous expression of ApoAV in HepG2 cells and ROR{alpha} also enhanced the activity of an ApoAV promoter construct in transiently transfected HepG2 cells. Deletion and mutation studies identified three AGGTCA motifs in the ApoAV promoter that mediate ROR{alpha} transactivation, one of which overlaps with a previously identified binding site for PPAR{alpha}. Together, these results suggest a novel mechanism whereby ROR{alpha} modulates lipid metabolism and implies ROR{alpha} as a potential target for the treatment of dyslipidemia and atherosclerosis.

  20. Code AI Personal Web Pages

    NASA Technical Reports Server (NTRS)

    Garcia, Joseph A.; Smith, Charles A. (Technical Monitor)

    1998-01-01

    The document consists of a publicly available web site (george.arc.nasa.gov) for Joseph A. Garcia's personal web pages in the AI division. Only general information will be posted and no technical material. All the information is unclassified.

  1. Typical and atypical AIS. Pathogenesis.

    PubMed

    Dudin, M; Pinchuk, D

    2012-01-01

    AIS hypothesis has the right to recognition, if it explains the transition of "healthy" vertebra column into status of "scoliotic" one. AIS is the most investigated disease in the history of orthopedics, but up the present time there is no clear explanation of some its phenomena: vertebra column mono-form deformation along with its poly etiology character, interrelation of its origin and development and child's growth process etc. The key for authors' view at AIS was scoliosis with non-standard (concave side) rotation. On the bases of its' multifunctional instrumental investigation results (Rtg, EMG, EEG, optical topography, hormonal and neuropeptides trials, thermo-vision methods and other) in comparison with typical AIS was worked out the new hypothesis, part of it is suggested for discussion. In the work under observation is the sequence of appearance of typical and atypical scoliosis symptomatology beginning from the preclinical stage. PMID:22744477

  2. Interactions between Hepatitis C Virus and the Human Apolipoprotein H Acute Phase Protein: A Tool for a Sensitive Detection of the Virus.

    PubMed

    Stefas, Ilias; Tigrett, Sylvia; Dubois, Grégor; Kaiser, Marco; Lucarz, Estelle; Gobby, Delphine; Bray, Dorothy; Ellerbrok, Heinz; Zarski, Jean Pierre; Veas, Francisco

    2015-01-01

    The Hepatitis C virus (HCV) infection exhibits a high global prevalence frequently associated with hepatocellular carcinoma, taking years to develop. Despite the standardization of highly sensitive HCV quantitative RT-PCR (qRT-PCR) detection methods, false-negative diagnoses may be generated with current methods, mainly due to the presence of PCR inhibitors and/or low viral loads in the patient's sample. These false-negative diagnoses impact both public health systems, in developing countries, and an in lesser extent, in developed countries, including both the risk of virus transmission during organ transplantation and/or blood transfusion and the quality of the antiviral treatment monitoring. To adopt an appropriate therapeutic strategy to improve the patient's prognosis, it is urgent to increase the HCV detection sensitivity. Based upon previous studies on HBV, we worked on the capacity of the scavenger acute phase protein, Apolipoprotein H (ApoH) to interact with HCV. Using different approaches, including immunoassays, antibody-inhibition, oxidation, ultracentrifugation, electron microscopy and RT-PCR analyses, we demonstrated specific interactions between HCV particles and ApoH. Moreover, when using a two-step HCV detection process, including capture of HCV by ApoH-coated nanomagnetic beads and a home-made real-time HCV-RT-PCR, we confirmed the presence of HCV for all samples from a clinical collection of HCV-seropositive patients exhibiting an RT-PCR COBAS® TaqMan® HCV Test, v2.0 (COBAS)-positive result. In contrast, for HCV-seropositive patients with either low HCV-load as determined with COBAS or exhibiting HCV-negative COBAS results, the addition of the two-step ApoH-HCV-capture and HCV-detection process was able to increase the sensitivity of HCV detection or more interestingly, detect in a genotype sequence-independent manner, a high-proportion (44%) of HCV/RNA-positive among the COBAS HCV-negative patients. Thus, the immune interaction between ApoH and

  3. Interactions between Hepatitis C Virus and the Human Apolipoprotein H Acute Phase Protein: A Tool for a Sensitive Detection of the Virus

    PubMed Central

    Dubois, Grégor; Kaiser, Marco; Lucarz, Estelle; Gobby, Delphine; Bray, Dorothy; Ellerbrok, Heinz; Zarski, Jean Pierre; Veas, Francisco

    2015-01-01

    The Hepatitis C virus (HCV) infection exhibits a high global prevalence frequently associated with hepatocellular carcinoma, taking years to develop. Despite the standardization of highly sensitive HCV quantitative RT-PCR (qRT-PCR) detection methods, false-negative diagnoses may be generated with current methods, mainly due to the presence of PCR inhibitors and/or low viral loads in the patient’s sample. These false-negative diagnoses impact both public health systems, in developing countries, and an in lesser extent, in developed countries, including both the risk of virus transmission during organ transplantation and/or blood transfusion and the quality of the antiviral treatment monitoring. To adopt an appropriate therapeutic strategy to improve the patient’s prognosis, it is urgent to increase the HCV detection sensitivity. Based upon previous studies on HBV, we worked on the capacity of the scavenger acute phase protein, Apolipoprotein H (ApoH) to interact with HCV. Using different approaches, including immunoassays, antibody-inhibition, oxidation, ultracentrifugation, electron microscopy and RT-PCR analyses, we demonstrated specific interactions between HCV particles and ApoH. Moreover, when using a two-step HCV detection process, including capture of HCV by ApoH-coated nanomagnetic beads and a home-made real-time HCV-RT-PCR, we confirmed the presence of HCV for all samples from a clinical collection of HCV-seropositive patients exhibiting an RT-PCR COBAS® TaqMan® HCV Test, v2.0 (COBAS)-positive result. In contrast, for HCV-seropositive patients with either low HCV-load as determined with COBAS or exhibiting HCV-negative COBAS results, the addition of the two-step ApoH-HCV-capture and HCV-detection process was able to increase the sensitivity of HCV detection or more interestingly, detect in a genotype sequence-independent manner, a high-proportion (44%) of HCV/RNA-positive among the COBAS HCV-negative patients. Thus, the immune interaction between Apo

  4. Effect of a high carbohydrate diet on the content of apolipoproteins C-II, C-III and E in human plasma high density lipoprotein subfractions.

    PubMed

    Sasaki, N; Holdsworth, G; Barnhart, R L; Srivastava, L S; Glueck, C J; Kashyap, M L; Jackson, R L

    1983-03-01

    The effect of isocaloric high and low carbohydrate (Carb) diets on the structure and apoprotein composition of plasma high density lipoproteins (HDL) was assessed in four healthy men. The high Carb diet contained 65% calories as Carb and 15% as fat; the low Carb was 15% and 65%, respectively, with protein fixed at 20% of calories in each case. Cholesterol was 400 mg/day and the P/S ratio of the fat was 0.4. Each diet was sequentially consumed for periods of 3 weeks. At the end of each 3-week study period, plasma HDL2 and HDL3 were isolated by zonal ultracentrifugation and their apoprotein and lipid compositions were determined. Compared to the low Carb diet, the high Carb diet was associated with an increase in the size of HDL2 (116.0 +/- 1.8 vs. 109.1 +/- 1.8 A) and in the content (mean weight % +/- SEM) of apoE (2.81 +/- 0.71 vs. 1.79 +/- 0.49, P less than 0.01) and of apoC-II (1.73 +/- 0.09 vs. 1.11 +/- 0.12, P less than 0.01). HDL2 apoC-III content was not significantly different on the two diets (6.49 +/- 0.50 vs. 7.42 +/- 1.21). On the two diets, HDL3 size and HDL3 apoE content were not significantly changed. HDL3 apoC-II and apoC-III, however, were higher on the high Carb diet, P less than 0.05. The ratio (by weight) of HDL2 apoE/HDL2 apoC-II + C-III increased on the high Carb diet compared to the low Carb diet (0.344 +/- 0.058 vs. 0.228 +/- 0.053, P less than 0.01). We suggest that the increased amount of apolipoprotein E in HDL2 may influence its rate of catabolic clearance and may account for the well-known decrease in plasma HDL-cholesterol in subjects on high Carb diets. PMID:6847745

  5. Targeted antivascular therapy with the apolipoprotein(a) kringle V, rhLK8, inhibits the growth and metastasis of human prostate cancer in an orthotopic nude mouse model.

    PubMed

    Lee, Ho-Jeong; Yu, Hyun-Kyung; Papadopoulos, John N; Kim, Seung Wook; He, Junqin; Park, Yong-Keun; Yoon, Yeup; Kim, Jang-Seong; Kim, Sun Jin

    2012-04-01

    Antivascular therapy has emerged as a rational strategy to improve the treatment of androgen-independent prostate cancer owing to the necessity of establishing a vascular network for the growth and progression of the primary and metastatic tumor. We determined whether recombinant human apolipoprotein(a) kringle V, rhLK8, produces therapeutic efficacy in an orthotopic human prostate cancer animal model. Fifty thousand androgen-independent human prostate cancer cells (PC-3MM2) were injected into the prostate of nude mice. After 3 days, these mice were randomized to receive the vehicle solution (intraperitoneally [i.p.], daily), paclitaxel (8 mg/kg i.p., weekly), rhLK8 (50 mg/kg i.p., daily), or a combination of paclitaxel and rhLK8 for 4 weeks. Treatment with paclitaxel or rhLK8 alone did not show significant therapeutic effects on tumor incidence or on tumor size compared with the control group. The combination of rhLK8 and paclitaxel significantly reduced tumor size and incidence of lymph node metastasis. Significant reduction in microvessel density and cellular proliferation and induction of apoptosis of tumor cells, and tumor-associated endothelial cells, were also achieved. Similarly, PC-3MM2 tumors growing in the tibia showed significant suppression of tumor growth and lymph node metastasis by the combination treatment with rhLK8 and paclitaxel. The integrity of the bone was significantly preserved, and apoptosis of tumor cells and tumor-associated endothelial cells was increased. In conclusion, these results suggest that targeting the tumor microenvironment with the antivascular effect of rhLK8 combined with conventional cytotoxic chemotherapy could be a new and effective approach in the treatment of androgen-independent prostate cancer and their metastases.

  6. Cloning of a cDNA encoding a putative human very low density lipoprotein/Apolipoprotein E receptor and assignment of the gene to chromosome 9pter-p23[sup 6

    SciTech Connect

    Gafvels, M.E.; Strauss, J.F. III ); Caird, M.; Patterson, D. ); Britt, D.; Jackson, C.L. )

    1993-11-01

    The authors report the cloning of a 3656-bp cDNA encoding a putative human very low density lipoprotein (VLDL)/apolipoprotein E (ApoE) receptor. The gene encoding this protein was mapped to chromosome 9pter-p23. Northern analysis of human RNA identified cognate mRNAs of 6.0 and 3.8 kb with most abundant expression in heart and skeletal muscle, followed by kidney, placenta, pancreas, and brain. The pattern of expression generally paralleled that of lipoprotein lipase mRNA but differed from that of the low density lipoprotein (LDL) receptor and the low density lipoprotein receptor-related protein/[alpha][sub 2]-macroglobulin receptor (LRP), which are members of the same gene family. VLDL/ApoE receptor message was not detected in liver, whereas mRNAs for both LDL receptor and LRP were found in hepatic tissue. In mouse 3T3-L1 cells, VLDL/ApoE receptor mRNA was induced during the transformation of the cells into adipocytes. Expression was also detected in human choriocarcinoma cells, suggesting that at least part of the expression observed in placenta may be in trophoblasts, cells which would be exposed to maternal blood. Expression in brain may be related to high levels of ApoE expression in that organ, an observation of potential relevance to the recently hypothesized role for ApoE in late onset Alzheimer disease. The results suggest that the putative VLDL/ApoE receptor could play a role in the uptake of triglyceride-rich lipoprotein particles by specific organs including striated and cardiac muscle and adipose tissue and in the transport of maternal lipids across the placenta. The findings presented here, together with recent observations from other laboratories, bring up the possibility that a single gene, the VLDL/ApoE receptor, may play a role in the pathogenesis of certain forms of atherosclerosis, Alzheimer disease, and obesity.

  7. D25V apolipoprotein C-III variant causes dominant hereditary systemic amyloidosis and confers cardiovascular protective lipoprotein profile.

    PubMed

    Valleix, Sophie; Verona, Guglielmo; Jourde-Chiche, Noémie; Nédelec, Brigitte; Mangione, P Patrizia; Bridoux, Frank; Mangé, Alain; Dogan, Ahmet; Goujon, Jean-Michel; Lhomme, Marie; Dauteuille, Carolane; Chabert, Michèle; Porcari, Riccardo; Waudby, Christopher A; Relini, Annalisa; Talmud, Philippa J; Kovrov, Oleg; Olivecrona, Gunilla; Stoppini, Monica; Christodoulou, John; Hawkins, Philip N; Grateau, Gilles; Delpech, Marc; Kontush, Anatol; Gillmore, Julian D; Kalopissis, Athina D; Bellotti, Vittorio

    2016-01-01

    Apolipoprotein C-III deficiency provides cardiovascular protection, but apolipoprotein C-III is not known to be associated with human amyloidosis. Here we report a form of amyloidosis characterized by renal insufficiency caused by a new apolipoprotein C-III variant, D25V. Despite their uremic state, the D25V-carriers exhibit low triglyceride (TG) and apolipoprotein C-III levels, and low very-low-density lipoprotein (VLDL)/high high-density lipoprotein (HDL) profile. Amyloid fibrils comprise the D25V-variant only, showing that wild-type apolipoprotein C-III does not contribute to amyloid deposition in vivo. The mutation profoundly impacts helical structure stability of D25V-variant, which is remarkably fibrillogenic under physiological conditions in vitro producing typical amyloid fibrils in its lipid-free form. D25V apolipoprotein C-III is a new human amyloidogenic protein and the first conferring cardioprotection even in the unfavourable context of renal failure, extending the evidence for an important cardiovascular protective role of apolipoprotein C-III deficiency. Thus, fibrate therapy, which reduces hepatic APOC3 transcription, may delay amyloid deposition in affected patients. PMID:26790392

  8. D25V apolipoprotein C-III variant causes dominant hereditary systemic amyloidosis and confers cardiovascular protective lipoprotein profile

    PubMed Central

    Valleix, Sophie; Verona, Guglielmo; Jourde-Chiche, Noémie; Nédelec, Brigitte; Mangione, P. Patrizia; Bridoux, Frank; Mangé, Alain; Dogan, Ahmet; Goujon, Jean-Michel; Lhomme, Marie; Dauteuille, Carolane; Chabert, Michèle; Porcari, Riccardo; Waudby, Christopher A.; Relini, Annalisa; Talmud, Philippa J.; Kovrov, Oleg; Olivecrona, Gunilla; Stoppini, Monica; Christodoulou, John; Hawkins, Philip N.; Grateau, Gilles; Delpech, Marc; Kontush, Anatol; Gillmore, Julian D.; Kalopissis, Athina D.; Bellotti, Vittorio

    2016-01-01

    Apolipoprotein C-III deficiency provides cardiovascular protection, but apolipoprotein C-III is not known to be associated with human amyloidosis. Here we report a form of amyloidosis characterized by renal insufficiency caused by a new apolipoprotein C-III variant, D25V. Despite their uremic state, the D25V-carriers exhibit low triglyceride (TG) and apolipoprotein C-III levels, and low very-low-density lipoprotein (VLDL)/high high-density lipoprotein (HDL) profile. Amyloid fibrils comprise the D25V-variant only, showing that wild-type apolipoprotein C-III does not contribute to amyloid deposition in vivo. The mutation profoundly impacts helical structure stability of D25V-variant, which is remarkably fibrillogenic under physiological conditions in vitro producing typical amyloid fibrils in its lipid-free form. D25V apolipoprotein C-III is a new human amyloidogenic protein and the first conferring cardioprotection even in the unfavourable context of renal failure, extending the evidence for an important cardiovascular protective role of apolipoprotein C-III deficiency. Thus, fibrate therapy, which reduces hepatic APOC3 transcription, may delay amyloid deposition in affected patients. PMID:26790392

  9. Identification of apolipoprotein using feature selection technique.

    PubMed

    Tang, Hua; Zou, Ping; Zhang, Chunmei; Chen, Rong; Chen, Wei; Lin, Hao

    2016-01-01

    Apolipoprotein is a kind of protein which can transport the lipids through the lymphatic and circulatory systems. The abnormal expression level of apolipoprotein always causes angiocardiopathy. Thus, correct recognition of apolipoprotein from proteomic data is very crucial to the comprehension of cardiovascular system and drug design. This study is to develop a computational model to predict apolipoproteins. In the model, the apolipoproteins and non-apolipoproteins were collected to form benchmark dataset. On the basis of the dataset, we extracted the g-gap dipeptide composition information from residue sequences to formulate protein samples. To exclude redundant information or noise, the analysis of various (ANOVA)-based feature selection technique was proposed to find out the best feature subset. The support vector machine (SVM) was selected as discrimination algorithm. Results show that 96.2% of sensitivity and 99.3% of specificity were achieved in five-fold cross-validation. These findings open new perspectives to improve apolipoproteins prediction by considering the specific dipeptides. We expect that these findings will help to improve drug development in anti-angiocardiopathy disease. PMID:27443605

  10. Identification of apolipoprotein using feature selection technique

    PubMed Central

    Tang, Hua; Zou, Ping; Zhang, Chunmei; Chen, Rong; Chen, Wei; Lin, Hao

    2016-01-01

    Apolipoprotein is a kind of protein which can transport the lipids through the lymphatic and circulatory systems. The abnormal expression level of apolipoprotein always causes angiocardiopathy. Thus, correct recognition of apolipoprotein from proteomic data is very crucial to the comprehension of cardiovascular system and drug design. This study is to develop a computational model to predict apolipoproteins. In the model, the apolipoproteins and non-apolipoproteins were collected to form benchmark dataset. On the basis of the dataset, we extracted the g-gap dipeptide composition information from residue sequences to formulate protein samples. To exclude redundant information or noise, the analysis of various (ANOVA)-based feature selection technique was proposed to find out the best feature subset. The support vector machine (SVM) was selected as discrimination algorithm. Results show that 96.2% of sensitivity and 99.3% of specificity were achieved in five-fold cross-validation. These findings open new perspectives to improve apolipoproteins prediction by considering the specific dipeptides. We expect that these findings will help to improve drug development in anti-angiocardiopathy disease. PMID:27443605

  11. Comparison of Apolipoprotein Concentrations and Values of APOB:APOAI with Traditional Lipid Measures in Women Diagnosed with Acute Cornonary Syndromes – A Preliminary Report

    PubMed Central

    Bergmann, Katarzyna; Sypniewska, Grazyna; Sawicki, Marcin

    2011-01-01

    BACKGROUND Acute coronary syndromes (ACS) are the leading cause of hospitalization and death in the modern world. Reliable indicators of risk assessment could be useful in clinical investigation. Results from recent studies suggest that apolipoprotein measurement and apoB:apoI ratio are superior to traditional lipids in the estimation of coronary risk. We compared apolipoprotein concentrations and apoB:apoAI index with traditional lipid measures in ACS patients. METHODS A study group consisted of 94 women diagnosed with ACS (STEMI=21, NSTEMI=25 and UA=48). Clinically healthy volunteers (n=30) served as controls. Measurements of serum cardiac TnI, lipid profile, high sensitivity C-reactive protein, apolipoprotein AI and apoB100 concentrations were performed and apoB:apoAI ratio was calculated. RESULTS ACS patients had significantly decreased median HDL-cholesterol, increased atherogenic indexes TC:HDL-C, apoB:apoAI and abnormally high CRP compared to controls. Median LDL-cholesterol and apoAI concentrations, although significantly higher in ACS patients, remained within the normal range. Comparison of atherogenic indexes in ACS patients has shown increased TC:HDL-C (>4) and apoB:apoAI (>0,3) in 60,4% and 96,8% of which 55,4% had moderate and high risk (>0,6). ApoB:apoAI ratio was of good diagnostic utility for discrimination between ACS cases and non-ACS controls (AUC=0,715), and little better than TC:HDL-C. In both groups similar percentage of increased LDL-C and triglycerides was observed whereas increased apoB concentration was three times more likely in ACS cases. The highest apoB:apoAI was observed predominantly in STEMI cases (49%) whereas the lowest in UA and NSTEMI (30%). CONCLUSIONS Determination of apolipoproteins and assessment of apoB:apoAI ratio seems to be useful and better tool than traditional lipid measures in assessing risk of acute coronary syndromes in women.

  12. Two amino acid substitutions in apolipoprotein B are in complete allelic association with the antigen group (x/y) polymorphism: Evidence for little recombination in the 3 prime end of the human gene

    SciTech Connect

    Dunning, A.M.; Renges, H.H.; Xu, Chunfang; Peacock, R.; Humphries, S.E.; Talmud, P.; Laxer, G. ); Brasseur, R. ); Tikkanen, M.J. ); Buetler, R. ); Saha, N. ); Hamsten, A. ); Rosseneu, M. )

    1992-01-01

    The authors report the identification of an A-to-G base change, in exon 29 of the apolipoprotein B (apo B) gene, that results in the substitution of serine for asparagine at residue 4,311 of mature apo B100. In a recent publication, Huang et al. have reported a C-to-T base change in exon 26 that causes the substitution of leucine for proline at residue 2712 of apo B. The authors have found complete linkage disequilibrium between the alleles at both these sites and an immunochemical polymorphism of LDL designated antigen group (x/y) (Ag(x/y)) in a sample of 118 Finnish individuals. This implies that either one of these substitutions - or both of them combined - could be the molecular basis of the Ag(x/y) antigenic determinants, with the allele encoding serine{sub 4311} plus leucine{sub 2,712} representing the Ag(x) epitope, and that encoding asparagine{sub 4,311} plus proline{sub 2,712} the Ag(y) epitope. In a sample of 90 healthy Swedish individuals the Leu{sub 2,712}/Ser{sub 4,311} allele is associated both with reduced serum levels of LDL cholesterol and apo B and with raised levels of HDL. They have also genotyped 523 individuals from European, Asian, Chinese, and Afro-Caribbean populations and have found complete association between the sites encoding residues 2,712 and 4,311 in all of these samples, although there are large allele frequency differences between these populations. Taken together, these data suggest that, since the divergence of the major ethnic groups, there has been little or no recombination in the 3' end of the human apo B gene.

  13. Transcriptional Regulation of Apolipoprotein A5 Gene Expression by the Nuclear Receptor ROR alpha

    SciTech Connect

    Genoux, Annelise; Dehondt, Helene; Helleboid-Chapman, Audrey; Duhem, Christian; Hum, Dean W.; Martin, Genevieve; Pennacchio, Len; Staels, Bart; Fruchart-Najib, Jamila; Fruchart, Jean-Charles

    2004-10-01

    Apolipoprotein A5 has recently been identified as a crucial determinant of plasma triglyceride levels. Our results showed that RORa up-regulates human APOA5 but has no effect on mouse apoa5 promoter. These data suggest an additional important physiological role for RORa in the regulation of genes involved in plasma triglyceride homeostasis in human and probably in the development of atherosclerosis

  14. Increased apolipoprotein E and c-fms gene expression without elevated interleukin 1 or 6 mRNA levels indicates selective activation of macrophage functions in advanced human atheroma.

    PubMed Central

    Salomon, R N; Underwood, R; Doyle, M V; Wang, A; Libby, P

    1992-01-01

    Cells found within atherosclerotic lesions can produce in culture protein mediators that may participate in atherogenesis. To test whether human atheromata actually contain transcripts for certain of these genes, we compared levels of mRNAs in carotid or coronary atheromata and in nonatherosclerotic human vessels by polymerase chain reaction (PCR) amplification of cDNAs reverse-transcribed from RNA. We measured PCR products (generated during exponential amplification) by incorporation of 32P-labeled primers. Levels of interleukin 1 alpha, 1 beta, or 6 mRNAs in plaques and controls did not differ. Compared to uninvolved vessels, plaques did contain higher levels of mRNA encoding platelet-derived growth factor A chain (42 +/- 24 vs. 12 +/- 10 fmol of product; mean +/- SD; n = 8 and 8, respectively; P = 0.007) and B chain (41 +/- 36 vs. 4 +/- 3 fmol of product, n = 14 and 6, respectively; P = 0.024). Atherosclerotic lesions consistently had much higher levels of apolipoprotein E (apoE) mRNA than did control vessels (131 +/- 71 vs. 5 +/- 3 fmol of product; n = 12 and 10, respectively; P less than 0.001). Direct RNA blot analyses confirmed elevated levels of apoE mRNA in plaque extracts. To test whether mononuclear phagocytes might be a source of the apoE mRNA, we studied a selective marker for cells of the monocytic lineage, the c-fms protooncogene, which encodes the receptor for macrophage colony-stimulating factor. Plaques also contained elevated levels of c-fms mRNA (30 +/- 17 vs. 5 +/- 3 fmol of product; n = 10 and 7, respectively; P = 0.002). Immunohistochemical colocalization demonstrated apoE protein in association with macrophages in plaques, whereas nonatherosclerotic vessels showed no immunoreactive apoE. ApoE produced locally in atheroma might modulate the functions of lesional T cells or promote "reverse cholesterol transport" by associating with high density lipoprotein particles, thus targeting them for peripheral uptake. Macrophages within the advanced

  15. Acute effects of moderate exercise on serum lipids, lipoproteins and apolipoproteins in sedentary young women.

    PubMed

    Imamura, H; Katagiri, S; Uchid, K; Miyamoto, N; Nakano, H; Shirota, T

    2000-12-01

    1. The aim of the present study was to examine the effects of moderate exercise on serum lipids, lipoproteins and apolipoproteins in seven sedentary young women under controlled conditions. 2. The subjects exercised on separate days for 30 or 60 min at an intensity of 60% of maximal oxygen uptake on a cycle ergometer. Total cholesterol, triglycerides, high-density lipoprotein-cholesterol (HDL-C), HDL2-C, HDL3-C, low-density lipoprotein-cholesterol, apolipoproteins A-I, A-II and B were measured in the serum at the end of the 60 min rest period before each exercise, immediately after the performance of each exercise and at 30 min and 1, 2 and 24 h after each exercise. 3. The results showed that there were no significant differences between the pre- and postexercise samples for any of the parameters tested. 4. The results of the present study suggest that a single bout of exercise designed to simulate a typical training workout has no noticeable effect on serum lipids, lipoproteins and apolipoproteins in normal sedentary young women who have normal lipid profiles, are in the follicular phase of their menstrual cycle and who consume a relatively low-fat diet.

  16. Lipoprotein and apolipoprotein levels among Mexican-Americans in Starr County, Texas.

    PubMed

    Hanis, C L; Hewett-Emmett, D; Douglas, T C; Schull, W J

    1991-01-01

    Mexican-Americans represent the single largest component of the US Hispanic population and have been shown to bear a disproportionate burden of chronic disease. A representative sample of 1,004 Mexican-Americans aged 15-74 years from Starr County, Tex., was recruited for this study. Each subject was provided a detailed physical evaluation that included measurement of fasting levels of cholesterol, triglycerides, high density lipoprotein (HDL) cholesterol and its subfractions (HDL2 and HDL3) alpha- and beta-lipoprotein cholesterol, and low density lipoprotein cholesterol. Apolipoproteins A-I, A-II, B, C-II, C-III, and E were determined for approximately 550 of these individuals. Age- and sex-specific mean levels and percentile cut points are presented. The distributions of lipoproteins are quite similar to those of the general population except for consistently higher triglycerides in males and females and lower HDL cholesterol levels in females. These findings are consistent with the high frequency of obesity. Comparative age- and sex-specific data for the apolipoproteins are not widely available. Where such data exist, apolipoprotein levels observed in the Mexican-American population tend to be similar to or lower than the comparative data. PMID:1987989

  17. Retinoic acid-induced expression of apolipoprotein D and concomitant growth arrest in human breast cancer cells are mediated through a retinoic acid receptor RARalpha-dependent signaling pathway.

    PubMed

    López-Boado, Y S; Klaus, M; Dawson, M I; López-Otín, C

    1996-12-13

    Apolipoprotein D (apoD) is a human plasma protein, belonging to the lipocalin superfamily, that is produced by a specific subtype of highly differentiated breast carcinomas and that is strongly up-regulated by retinoic acid (RA) in breast cancer cells. In this work, we have examined the molecular mechanisms mediating the induction of apoD gene expression by retinoids in T-47D human breast cancer cells. Northern blot analysis revealed that Ro40-6055, a synthetic retinoid that selectively binds and activates the retinoic acid receptor RARalpha, induced the accumulation of apoD mRNA in breast cancer cells in a time- and dose-dependent manner. The time course analysis demonstrated that apoD mRNA was induced 14-fold over control cells after 48 h of incubation with 10(-8) M Ro40-6055. As little as 10(-11) M of this retinoid induced apoD mRNA 5-fold over the control, whereas incubation with 10(-7) M Ro40-6055 induced maximally 15-fold over control cells. RARalpha-selective antagonists counteracted the inductive effects of all-trans-RA, 9-cis-RA, and Ro40-6055 on the expression of apoD, when present at the same concentration as the retinoid agonists. By contrast, RARbeta-, RARgamma-, and RXR-selective retinoids did not affect apoD gene expression. The retinoid agonist Ro40-6055 had an antiproliferative effect on T-47D cells, with maximal growth inhibition of approximately 60% obtained after 7 days of incubation with 10(-7) M. This antiproliferative effect could be counteracted by a 100-fold excess of the antagonist Ro41-5253. Treatment of the cells with retinoids that do not bind the nuclear retinoic acid receptors did not affect apoD expression, despite the fact that they did have a strong antiproliferative effect on T-47D cells. On the basis of these results, a role for RARalpha on apoD gene expression induction by retinoids in breast cancer cells is proposed.

  18. HDL-apolipoprotein A-I exchange is independently associated with cholesterol efflux capacity

    PubMed Central

    Borja, Mark S.; Ng, Kit F.; Irwin, Angela; Hong, Jaekyoung; Wu, Xing; Isquith, Daniel; Zhao, Xue-Qiao; Prazen, Bryan; Gildengorin, Virginia; Oda, Michael N.; Vaisar, Tomáš

    2015-01-01

    HDL is the primary mediator of cholesterol mobilization from the periphery to the liver via reverse cholesterol transport (RCT). A critical first step in this process is the uptake of cholesterol from lipid-loaded macrophages by HDL, a function of HDL inversely associated with prevalent and incident cardiovascular disease. We hypothesized that the dynamic ability of HDL to undergo remodeling and exchange of apoA-I is an important and potentially rate-limiting aspect of RCT. In this study, we investigated the relationship between HDL-apoA-I exchange (HAE) and serum HDL cholesterol (HDL-C) efflux capacity. We compared HAE to the total and ABCA1-specific cholesterol efflux capacity of 77 subjects. We found that HAE was highly correlated with both total (r = 0.69, P < 0.0001) and ABCA1-specific (r = 0.47, P < 0.0001) efflux, and this relationship remained significant after adjustment for HDL-C or apoA-I. Multivariate models of sterol efflux capacity indicated that HAE accounted for approximately 25% of the model variance for both total and ABCA1-specific efflux. We conclude that the ability of HDL to exchange apoA-I and remodel, as measured by HAE, is a significant contributor to serum HDL efflux capacity, independent of HDL-C and apoA-I, indicating that HDL dynamics are an important factor in cholesterol efflux capacity and likely RCT. PMID:26254308

  19. HDL-apolipoprotein A-I exchange is independently associated with cholesterol efflux capacity.

    PubMed

    Borja, Mark S; Ng, Kit F; Irwin, Angela; Hong, Jaekyoung; Wu, Xing; Isquith, Daniel; Zhao, Xue-Qiao; Prazen, Bryan; Gildengorin, Virginia; Oda, Michael N; Vaisar, Tomáš

    2015-10-01

    HDL is the primary mediator of cholesterol mobilization from the periphery to the liver via reverse cholesterol transport (RCT). A critical first step in this process is the uptake of cholesterol from lipid-loaded macrophages by HDL, a function of HDL inversely associated with prevalent and incident cardiovascular disease. We hypothesized that the dynamic ability of HDL to undergo remodeling and exchange of apoA-I is an important and potentially rate-limiting aspect of RCT. In this study, we investigated the relationship between HDL-apoA-I exchange (HAE) and serum HDL cholesterol (HDL-C) efflux capacity. We compared HAE to the total and ABCA1-specific cholesterol efflux capacity of 77 subjects. We found that HAE was highly correlated with both total (r = 0.69, P < 0.0001) and ABCA1-specific (r = 0.47, P < 0.0001) efflux, and this relationship remained significant after adjustment for HDL-C or apoA-I. Multivariate models of sterol efflux capacity indicated that HAE accounted for approximately 25% of the model variance for both total and ABCA1-specific efflux. We conclude that the ability of HDL to exchange apoA-I and remodel, as measured by HAE, is a significant contributor to serum HDL efflux capacity, independent of HDL-C and apoA-I, indicating that HDL dynamics are an important factor in cholesterol efflux capacity and likely RCT.

  20. Sequence-specific apolipoprotein A-I effects on lecithin:cholesterol acyltransferase activity.

    PubMed

    Dergunov, Alexander D

    2013-06-01

    Existing kinetic data of cholesteryl ester formation by lecithin:cholesterol acyltransferase in discoidal high-density lipoproteins with 34 mutations of apoA-I that involved all putative helices were grouped by cluster analysis into four noncoincident regions with mutations both without any functional impairment and with profound isolated (V- and K-mutations) or common (VK-mutations) effect on V(max)(app) and K(m)(app). Data were analyzed with a new kinetic model of LCAT activity at interface that exploits the efficiency of LCAT binding to the particle, particle dimensions, and surface concentrations of phosphatidylcholine and cholesterol. V-mutations with major location in the central part and C-domain affected the second-order rate constant of cholesteryl ester formation at the solvolysis of acyl-enzyme intermediate by cholesterol as nucleophile. The central region in apoA-I sequence is suggested to influence the proper positioning of cholesterol molecule toward LCAT active center with major contribution of arginine residue(s). K-mutations with major location in N-domain may affect binding and stability of enzyme-phosphatidylcholine complex. VK-mutations may possess mixed effects; the independent binding measurement may segregate individual steps. PMID:23516040

  1. Role of apolipoprotein E in neurodegenerative diseases

    PubMed Central

    Giau, Vo Van; Bagyinszky, Eva; An, Seong Soo A; Kim, Sang Yun

    2015-01-01

    Apolipoprotein E (APOE) is a lipid-transport protein abundantly expressed in most neurons in the central nervous system. APOE-dependent alterations of the endocytic pathway can affect different functions. APOE binds to cell-surface receptors to deliver lipids and to the hydrophobic amyloid-β peptide, regulating amyloid-β aggregations and clearances in the brain. Several APOE isoforms with major structural differences were discovered and shown to influence the brain lipid transport, glucose metabolism, neuronal signaling, neuroinflammation, and mitochondrial function. This review will summarize the updated research progress on APOE functions and its role in Alzheimer’s disease, Parkinson’s disease, cardiovascular diseases, multiple sclerosis, type 2 diabetes mellitus, Type III hyperlipoproteinemia, vascular dementia, and ischemic stroke. Understanding the mutations in APOE, their structural properties, and their isoforms is important to determine its role in various diseases and to advance the development of therapeutic strategies. Targeting APOE may be a potential approach for diagnosis, risk assessment, prevention, and treatment of various neurodegenerative and cardiovascular diseases in humans. PMID:26213471

  2. Can novel Apo A-I polymorphisms be responsible for low HDL in South Asian immigrants?

    PubMed Central

    Dodani, Sunita; Dong, Yanbin; Zhu, Haidong; George, Varghese

    2008-01-01

    Coronary artery disease (CAD) is the leading cause of death in the world. Even though its rates have decreased worldwide over the past 30 years, event rates are still high in South Asians. South Asians are known to have low high-density lipoprotein (HDL) levels. The objective of this study was to identify Apolipoprotein A-I (Apo A-I) polymorphisms, the main protein component of HDL and explore its association with low HDL levels in South Asians. A pilot study on 30 South Asians was conducted and 12-h fasting samples for C-reactive protein, total cholesterol, HDL, low-density lipoprotein (LDL), triglycerides, Lipoprotein (a), Insulin, glucose levels, DNA extraction, and sequencing of Apo A-I gene were done. DNA sequencing revealed six novel Apo A-I single nucleotide polymorphisms (SNPs) in South Asians, one of which (rs 35293760, C938T) was significantly associated with low (<40 mg/dl) HDL levels (P = 0.004). The association was also seen with total cholesterol (P = 0.026) and LDL levels (P = 0.032). This pilot work has highlighted some of the gene-environment associations that could be responsible for low HDL and may be excess CAD in South Asians. Further larger studies are required to explore and uncover these associations that could be responsible for excess CAD risk in South Asians. PMID:20300285

  3. AIS Investigation of Agricultural Monocultures

    NASA Technical Reports Server (NTRS)

    Wood, B. L.; Wrigley, R. C.

    1985-01-01

    Airborne Imaging Spectrometer (AIS) data were acquired over an agricultural area in eastern San Joaquin County, California in July, 1984. Cover type information was subsequently collected for all fields along this flight line. The lack of detailed ground data on individual fields, however, limited AIS data analysis to a qualitative comparison of the spectral reflectance curves for a total of nine cover types. Based on this analysis, it appears that cover types with a positive slope in the 1550 to 1700 nm region have a higher spectral response in the 1200 to 1300 nm region compared to those cover types with a negative slope in the 1550 to 1700 nm region. Within cover type, spectral variability was also found to be greater than that between cover types. Given the lack of additional field data, the reason for these differences is a matter of speculation.

  4. Differential expression of oxidation-specific epitopes and apolipoprotein(a) in progressing and ruptured human coronary and carotid atherosclerotic lesions.

    PubMed

    van Dijk, Rogier A; Kolodgie, Frank; Ravandi, Amir; Leibundgut, Gregor; Hu, Patrick P; Prasad, Anand; Mahmud, Ehtisham; Dennis, Edward; Curtiss, Linda K; Witztum, Joseph L; Wasserman, Bruce A; Otsuka, Fumiyuki; Virmani, Renu; Tsimikas, Sotirios

    2012-12-01

    The relationships between oxidation-specific epitopes (OSE) and lipoprotein (a) [Lp(a)] and progressive atherosclerosis and plaque rupture have not been determined. Coronary artery sections from sudden death victims and carotid endarterectomy specimens were immunostained for apoB-100, oxidized phospholipids (OxPL), apo(a), malondialdehyde-lysine (MDA), and MDA-related epitopes detected by antibody IK17 and macrophage markers. The presence of OxPL captured in carotid and saphenous vein graft distal protection devices was determined with LC-MS/MS. In coronary arteries, OSE and apo(a) were absent in normal coronary arteries and minimally present in early lesions. As lesions progressed, apoB and MDA epitopes did not increase, whereas macrophage, apo(a), OxPL, and IK17 epitopes increased proportionally, but they differed according to plaque type and plaque components. Apo(a) epitopes were present throughout early and late lesions, especially in macrophages and the necrotic core. IK17 and OxPL epitopes were strongest in late lesions in macrophage-rich areas, lipid pools, and the necrotic core, and they were most specifically associated with unstable and ruptured plaques. Specific OxPL were present in distal protection devices. Human atherosclerotic lesions manifest a differential expression of OSEs and apo(a) as they progress, rupture, and become clinically symptomatic. These findings provide a rationale for targeting OSE for biotheranostic applications in humans. PMID:22969153

  5. Formal verification of AI software

    NASA Technical Reports Server (NTRS)

    Rushby, John; Whitehurst, R. Alan

    1989-01-01

    The application of formal verification techniques to Artificial Intelligence (AI) software, particularly expert systems, is investigated. Constraint satisfaction and model inversion are identified as two formal specification paradigms for different classes of expert systems. A formal definition of consistency is developed, and the notion of approximate semantics is introduced. Examples are given of how these ideas can be applied in both declarative and imperative forms.

  6. Situated, strategic, and AI-Enhanced technology introduction to healthcare.

    PubMed

    Bushko, Renata G

    2005-01-01

    We work hard on creating AI-wings for physicians to let them fly higher and faster in diagnosing patients--a task that physicians do not want to automate. What we do not work hard on is determining the ENVIRONMENT in which physicians' AI wings are supposed to function. It seems to be a job for social/business analysts that have their own separate kingdom. For the sake of all of us (potential patients!) social/business consultants and their methodologies should not be treated as a separate kingdom. The most urgent task is to achieve synergy between (1) AI/Fuzzy/Neural research, (2) Applied medical AI, (3) Social/Business research on medical institutions. We need this synergy in order to assure humanistic medical technology; technology flexible and sensitive enough to facilitate healthcare work while leaving space for human pride and creativity. In order to achieve humanistic technology, designers should consider the impact of technological breakthroughs on the organizations in which this technology will function and the nature of work of humans destined to use this technology. Situated (different for each organization), Strategic (based on an in-depth knowledge of Healthcare business), and AI-Enhanced (ended with a dynamic model) method for introducing technology to Healthcare allows identifying areas where technology can make medical work easier. Using this method before automating human work will get us closer to the ideal where there is no discontinuity between design and use of programs; where the technology matches users' needs perfectly--the world with humanistic technology and healthcare workers with AI-wings.

  7. Comparative Effects of Diet-Induced Lipid Lowering Versus Lipid Lowering Along With Apo A-I Milano Gene Therapy on Regression of Atherosclerosis.

    PubMed

    Wang, Lai; Tian, Fang; Arias, Ana; Yang, Mingjie; Sharifi, Behrooz G; Shah, Prediman K

    2016-05-01

    Apolipoprotein A-1 (Apo A-I) Milano, a naturally occurring Arg173to Cys mutant of Apo A-1, has been shown to reduce atherosclerosis in animal models and in a small phase 2 human trial. We have shown the superior atheroprotective effects of Apo A-I Milano (Apo A-IM) gene compared to wild-type Apo A-I gene using transplantation of retrovirally transduced bone marrow in Apo A-I/Apo E null mice. In this study, we compared the effect of dietary lipid lowering versus lipid lowering plus Apo A-IM gene transfer using recombinant adeno-associated virus (rAAV) 8 as vectors on atherosclerosis regression in Apo A-I/Apo E null mice. All mice were fed a high-cholesterol diet from age of 6 weeks until week 20, and at 20 weeks, 10 mice were euthanized to determine the extent of atherosclerosis. After 20 weeks, an additional 20 mice were placed on either a low-cholesterol diet plus empty rAAV (n = 10) to serve as controls or low-cholesterol diet plus 1 single intravenous injection of 1.2 × 10(12)vector genomes of adeno-associated virus (AAV) 8 vectors expressing Apo A-IM (n = 10). At the 40 week time point, intravenous AAV8 Apo A-IM recipients showed a significant regression of atherosclerosis in the whole aorta (P< .01), aortic sinuses (P< .05), and brachiocephalic arteries (P< .05) compared to 20-week-old mice, whereas low-cholesterol diet plus empty vector control group showed no significant regression in lesion size. Immunostaining showed that compared to the 20-week-old mice, there was a significantly reduced macrophage content in the brachiocephalic (P< .05) and aortic sinus plaques (P< .05) of AAV8 Apo A-IM recipients. These data show that although dietary-mediated cholesterol lowering halts progression of atherosclerosis, it does not induce regression, whereas combination of low-cholesterol diet and AAV8 mediated Apo A-I Milano gene therapy induces rapid and significant regression of atherosclerosis in mice. These data provide support for the potential feasibility of this

  8. Familial apolipoprotein Al and apolipoprotein CIII deficiency: subclass distribution, composition, and morphology of lipoproteins in a disorder associated with premature atherosclerosis

    SciTech Connect

    Forte, T.M.; Nichols, A.V.; Krauss, R.M.; Norum, R.A.

    1984-11-01

    Lipoprotein classes isolated from the plasma of two patients with apolipoprotein AI (apo AI) and apolipoprotein CIII (apo CIII) deficiency were characterized and compared with those of healthy, age- and sex-matched controls. The plasma triglyceride values for patients 1 and 2 were 31 and 51 mg/dl, respectively, and their cholesterol values were 130 and 122 mg/dl, respectively; the patients, however, had no measurable high density lipoprotein (HDL)-cholesterol. Analytic ultracentrifugation showed that patients' S/sub f//sup 0/ 0-20 lipoproteins posses a single peak with S/sub f//sup 0/ rates of 7.4 and 7.6 for patients 1 and 2, respectively, which is similar to that of the controls. The concentration of low density lipoprotein (LDL) (S/sub f//sup 0/ 0-12) particles, although within normal range (331 and 343 mg/dl for patients 1 and 2, respectively), was 35% greater than that of controls. Intermediate density lipoproteins (IDL) and very low density lipoproteins (VLDL) (S/sub f//sup 0/ 20-400) were extremely low in the patients. HDL in the patients had a calculated mass of 15.4 and 11.8 mg/dl for patients 1 and 2, respectively. No HDL could be detected by analytic ultracentrifugation, but polyacrylamide gradient gel electrophoresis (gge) revealed that patients possessed two major HDL subclasses: (HDL/sub sb/)/sub gge/ at 11.0 nm and (HDL/sub 3b/)/sub gge/ at 7.8 nm. The major peak in the controls (HDL/sub 3a/)/sub gge/, was lacking in the patients.

  9. The AIS-5000 parallel processor

    SciTech Connect

    Schmitt, L.A.; Wilson, S.S.

    1988-05-01

    The AIS-5000 is a commercially available massively parallel processor which has been designed to operate in an industrial environment. It has fine-grained parallelism with up to 1024 processing elements arranged in a single-instruction multiple-data (SIMD) architecture. The processing elements are arranged in a one-dimensional chain that, for computer vision applications, can be as wide as the image itself. This architecture has superior cost/performance characteristics than two-dimensional mesh-connected systems. The design of the processing elements and their interconnections as well as the software used to program the system allow a wide variety of algorithms and applications to be implemented. In this paper, the overall architecture of the system is described. Various components of the system are discussed, including details of the processing elements, data I/O pathways and parallel memory organization. A virtual two-dimensional model for programming image-based algorithms for the system is presented. This model is supported by the AIS-5000 hardware and software and allows the system to be treated as a full-image-size, two-dimensional, mesh-connected parallel processor. Performance bench marks are given for certain simple and complex functions.

  10. Identification of the thiol ester lipids in apolipoprotein B

    SciTech Connect

    Huang, G.; Lee, D.M.; Singh, S.

    1988-03-08

    Human plasma low-density lipoproteins of 1.032-1.043 g/mL density were totally delipidized. The reduced and carboxymethylated apolipoprotein B was incubated with 50 mM (/sup 14/C) methylamine at pH 8.5 at 30 /sup 0/C. Covalent incorporation of (/sup 14/C) methylamine was observed with concomitant generation of new sulfhydryl groups, which could be blocked with (/sup 3/H)- or (/sup 14/C)iodoacetic acid. One type of the (/sup 14/C) methylamine-modified products was separated from the protein and was found to be lipid in nature. Its R/sub f/ on thin-layer chromatography (TLC) was similar to that of the synthetic N-methyl fatty acyl amides. After purification with TLC and transesterification in 3 N methanolic HCl, methyl esters of C/sub 16/ and C/sub 18/ fatty acids at 1:1 ratio were identified by gas-liquid chromatography. The transesterification method was verified with the known N-methyl fatty acyl amides. These results suggest the presence of labile thiol ester linked palmitate and stearate in apolipoprotein B. Under mild alkaline conditions, the thiol ester bonds are broken by methylamine and form N-methyl fatty acyl amides and release new -SH groups. Intramolecular thiol ester bonds linked between cysteine side chains and acidic amino acid residues were also found present, which will be reported separately.

  11. Macrophage apoAI protects against dyslipidemia-induced dermatitis and atherosclerosis without affecting HDL.

    PubMed

    Tavori, Hagai; Su, Yan Ru; Yancey, Patricia G; Giunzioni, Ilaria; Wilhelm, Ashley J; Blakemore, John L; Zabalawi, Manal; Linton, MacRae F; Sorci-Thomas, Mary G; Fazio, Sergio

    2015-03-01

    Tissue cholesterol accumulation, macrophage infiltration, and inflammation are features of atherosclerosis and some forms of dermatitis. HDL and its main protein, apoAI, are acceptors of excess cholesterol from macrophages; this process inhibits tissue inflammation. Recent epidemiologic and clinical trial evidence questions the role of HDL and its manipulation in cardiovascular disease. We investigated the effect of ectopic macrophage apoAI expression on atherosclerosis and dermatitis induced by the combination of hypercholesterolemia and absence of HDL in mice. Hematopoietic progenitor cells were transduced to express human apoAI and transplanted into lethally irradiated LDL receptor(-/-)/apoAI(-/-) mice, which were then placed on a high-fat diet for 16 weeks. Macrophage apoAI expression reduced aortic CD4(+) T-cell levels (-39.8%), lesion size (-25%), and necrotic core area (-31.6%), without affecting serum HDL or aortic macrophage levels. Macrophage apoAI reduced skin cholesterol by 39.8%, restored skin morphology, and reduced skin CD4(+) T-cell levels. Macrophage apoAI also reduced CD4(+) T-cell levels (-32.9%) in skin-draining lymph nodes but had no effect on other T cells, B cells, dendritic cells, or macrophages compared with control transplanted mice. Thus, macrophage apoAI expression protects against atherosclerosis and dermatitis by reducing cholesterol accumulation and regulating CD4(+) T-cell levels, without affecting serum HDL or tissue macrophage levels.

  12. Apolipoprotein C-III(Lys58----Glu). Identification of an apolipoprotein C-III variant in a family with hyperalphalipoproteinemia.

    PubMed Central

    von Eckardstein, A; Holz, H; Sandkamp, M; Weng, W; Funke, H; Assmann, G

    1991-01-01

    Apolipoprotein C-III is a major protein constituent of triglyceride rich lipoproteins and HDL. It occurs in plasma in three isoforms differing by their sialic acid content. Apo C-III putatively inhibits lipolysis and the apo E mediated hepatic uptake of remnants from triglyceride rich particles. We identified a heterozygous carrier of an apolipoprotein C-III variant by the presence of additional bands after isoelectric focusing (IEF) of VLDL. Structural analysis of the variant protein by HPLC, time-of-flight secondary ion mass spectrometry, and automated gas phase sequencing revealed a lysine to glutamic acid replacement in position 58. The underlying A to G exchange was verified by direct sequencing subsequent to amplification by polymerase chain reaction of exon 4 of the apo C-III gene. Family studies revealed vertical transmission of this defect. The two variant carriers exhibited plasma concentrations of HDL cholesterol and apo A-I above the 95th percentiles of sex matched controls whereas the unaffected father and sister showed normal values. The plasma concentrations of apo C-III in the two variant carriers were decreased by 30-40% compared with those of the two unaffected family members and to random controls. Using two-dimensional immunoelectrophoresis as well as IEF and subsequent scanning densitometry, we found that the low serum concentration of apo C-III was a consequence of diminished concentrations of the variant apo C-III isoproteins in both VLDL (15% of normal) and HDL (25% of normal). Apo C-III(Lys58----Glu) heterozygotes possessed unusual HDL as demonstrated by nondenaturing gradient gel electrophoresis. They consisted mainly of HDL2b and contained a proportion of atypically large particles, enriched in apo E, with a Stokes diameter of 13-18 nm and resembling HDLc. In conclusion, heterozygosity for a structural apo C-III variant--apo C-III(Lys58----Glu)--was identified in two hyperalphalipoproteinemic subjects characterized by the presence of low

  13. JGOMAS: New Approach to AI Teaching

    ERIC Educational Resources Information Center

    Barella, A.; Valero, S.; Carrascosa, C.

    2009-01-01

    This paper presents a new environment for teaching practical work in AI subjects. The main purpose of this environment is to make AI techniques more appealing to students and to facilitate the use of the toolkits which are currently widely used in research and development. This new environment has a toolkit for developing and executing agents,…

  14. The Relevance of AI Research to CAI.

    ERIC Educational Resources Information Center

    Kearsley, Greg P.

    This article provides a tutorial introduction to Artificial Intelligence (AI) research for those involved in Computer Assisted Instruction (CAI). The general theme is that much of the current work in AI, particularly in the areas of natural language understanding systems, rule induction, programming languages, and socratic systems, has important…

  15. Effect of pravastatin, an HMG CoA reductase inhibitor, and cholestyramine, a bile acid sequestrant, on lipoprotein particles defined by their apolipoprotein composition.

    PubMed

    Bard, J M; Parra, H J; Douste-Blazy, P; Fruchart, J C

    1990-03-01

    This study compares the effects of cholestyramine (16 g/d) and pravastatin (40 mg/d) on lipoprotein particles defined by their apolipoprotein composition (Lp A-I, Lp A-II:A-I, Lp E:B, and Lp C-III:B). Analysis was performed after 4, 8, and 12 weeks of therapy. Low-density lipoprotein (LDL) cholesterol decreased by 25.1% to 35.0% with cholestyramine and 26.2% to 30.7% with pravastatin, while triglycerides decreased slightly with pravastatin therapy and increased slightly during cholestyramine administration. The fall in cholesterol was mainly due to a decrease in very-low-density lipoprotein (VLDL) and LDL cholesterol; high-density lipoprotein (HDL) cholesterol increased. Apolipoprotein B was reduced dramatically (by 21.7% to 30.5% with cholestyramine and 27.7% to 37.4% with pravastatin). No significant effect on apolipoproteins C-III and E was observed with cholestyramine, while pravastatin reduced these parameters slightly. Apolipoprotein A-I increased during therapy with both drugs, while apolipoprotein A-II was slightly decreased. Although the drugs had nearly the same effects on plasma lipids, their influence on lipoprotein particles defined by their apolipoprotein composition was substantially different. Lp A-II:A-I was increased by both drugs (+8.1% to +41.2% for cholestyramine and +7.2% to +32.6% for pravastatin). Lp A-I was also increased with both drugs, but cholestyramine had a more constant and pronounced effect than pravastatin (+15.1% to +21.7% for cholestyramine and +1.7% to +13.0% for pravastatin). Lp E:B and Lp C-III:B were consistently decreased by pravastatin (-10.2% to -36.5% for LP E:B and -7.2% to -20.9% for Lp C-III:B), while cholestyramine had variable effects on these particles.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Apolipoprotein E Polymorphism in Tuberculosis Patients

    NASA Astrophysics Data System (ADS)

    Naserpour Farivar, Taghi; Sharifi Moud, Batool; Sargazi, Mansur; Moeenrezakhanlou, Alireza

    In this study, we aimed to determine the significance of association between Tuberculosis and apolipoprotein E polymorphism. The apolipoprotein E genotypes were assayed in 250 tuberculosis patients by polymerase chain reaction followed by enzymatic digestion with Hha I. The results were compared with the results of the same experiments on 250 sex and age matched control peoples. Present results showed that in studied populations, prevalence of E4 genotype was lower in controls than in patients (8 v. 13.2%; OR = 1.75, p<0.05) and prevalence of E3 genotype was high in controls than in patients (86 v.51%; OR = 0.17, p<0.05). Statistically significant difference was found between patients and controls with respect to ɛ2 allele frequencies, while ɛ2 allele frequency was found to be much less prevalent in controls (6%) than in patients (35.8%; OR = 8.72, p<0.05). Also, our study revealed that there is an association between apolipoprotein E genotypes and amplitude to tuberculosis in studied populations. However, large population-based studies are needed to understand the exact role played by the locus in causing the condition.

  17. Direct Transcriptional Effects of Apolipoprotein E

    PubMed Central

    Theendakara, Veena; Peters-Libeu, Clare A.; Spilman, Patricia; Poksay, Karen S.

    2016-01-01

    A major unanswered question in biology and medicine is the mechanism by which the product of the apolipoprotein E ε4 allele, the lipid-binding protein apolipoprotein E4 (ApoE4), plays a pivotal role in processes as disparate as Alzheimer's disease (AD; in which it is the single most important genetic risk factor), atherosclerotic cardiovascular disease, Lewy body dementia, hominid evolution, and inflammation. Using a combination of neural cell lines, skin fibroblasts from AD patients, and ApoE targeted replacement mouse brains, we show in the present report that ApoE4 undergoes nuclear translocation, binds double-stranded DNA with high affinity (low nanomolar), and functions as a transcription factor. Using chromatin immunoprecipitation and high-throughput DNA sequencing, our results indicate that the ApoE4 DNA binding sites include ∼1700 gene promoter regions. The genes associated with these promoters provide new insight into the mechanism by which AD risk is conferred by ApoE4, because they include genes associated with trophic support, programmed cell death, microtubule disassembly, synaptic function, aging, and insulin resistance, all processes that have been implicated in AD pathogenesis. SIGNIFICANCE STATEMENT This study shows for the first time that apolipoprotein E4 binds DNA with high affinity and that its binding sites include 1700 promoter regions that include genes associated with neurotrophins, programmed cell death, synaptic function, sirtuins and aging, and insulin resistance, all processes that have been implicated in Alzheimer's disease pathogenesis. PMID:26791201

  18. Direct Transcriptional Effects of Apolipoprotein E.

    PubMed

    Theendakara, Veena; Peters-Libeu, Clare A; Spilman, Patricia; Poksay, Karen S; Bredesen, Dale E; Rao, Rammohan V

    2016-01-20

    A major unanswered question in biology and medicine is the mechanism by which the product of the apolipoprotein E ε4 allele, the lipid-binding protein apolipoprotein E4 (ApoE4), plays a pivotal role in processes as disparate as Alzheimer's disease (AD; in which it is the single most important genetic risk factor), atherosclerotic cardiovascular disease, Lewy body dementia, hominid evolution, and inflammation. Using a combination of neural cell lines, skin fibroblasts from AD patients, and ApoE targeted replacement mouse brains, we show in the present report that ApoE4 undergoes nuclear translocation, binds double-stranded DNA with high affinity (low nanomolar), and functions as a transcription factor. Using chromatin immunoprecipitation and high-throughput DNA sequencing, our results indicate that the ApoE4 DNA binding sites include ∼1700 gene promoter regions. The genes associated with these promoters provide new insight into the mechanism by which AD risk is conferred by ApoE4, because they include genes associated with trophic support, programmed cell death, microtubule disassembly, synaptic function, aging, and insulin resistance, all processes that have been implicated in AD pathogenesis. Significance statement: This study shows for the first time that apolipoprotein E4 binds DNA with high affinity and that its binding sites include 1700 promoter regions that include genes associated with neurotrophins, programmed cell death, synaptic function, sirtuins and aging, and insulin resistance, all processes that have been implicated in Alzheimer's disease pathogenesis.

  19. Comparison of the effect of fluvastatin, an hydroxymethyl glutaryl coenzyme A reductase inhibitor, and cholestyramine, a bile acid sequestrant, on lipoprotein particles defined by apolipoprotein composition.

    PubMed

    Bard, J M; Dallongeville, J; Hagen, E; Pfister, P; Ose, L; Fruchart, J C; Duriez, P

    1995-11-01

    In a double-blind, parallel-group, randomized study, the effects of fluvastatin (FLUV) 20 and 40 mg/d on lipoprotein particle levels were compared with those of cholestyramine (CME) 16 g/d. Lipoparticles were defined by apolipoprotein composition as either those containing both apolipoprotein (apo) B and apo E or CIII (lipoprotein [Lp] E-B or Lp CIII-B) or those containing apo AI alone (Lp AI) or in association with apo AII (Lp AI-AII). After an 8-week dietary stabilization period, 100 hypercholesterolemic patients were treated with FLUV 20 mg/d for 6 weeks and 40 mg/d for an additional 6 weeks and were compared with 48 hypercholesterolemic subjects treated with CME 16 g/d. Treatment with FLUV (40 mg/d) or CME (16 g/d) for 12 weeks was associated with a significant reduction in plasma cholesterol and low-density lipoprotein (LDL) cholesterol and a significant increase in high-density lipoprotein (HDL) cholesterol. However, plasma triglyceride levels decreased following FLUV treatment, whereas they increased with CME. These changes were associated with a significant reduction in the levels of apo B (FLUV, -24%, P < .001; CME, -26%, P < .001), apo E (FLUV, -36%, P < .001; CME, -32%, P < .001), and apo CIII (FLUV, -21%, P < .001; CME, -6%, NS).(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Apolipoprotein A-II is a key regulatory factor of HDL metabolism as appears from studies with transgenic animals and clinical outcomes.

    PubMed

    Maïga, Sira Fatoumata; Kalopissis, Athina-Despina; Chabert, Michèle

    2014-01-01

    The structure and metabolism of HDL are linked to their major apolipoproteins (apo) A-I and A-II. HDL metabolism is very dynamic and depends on the constant remodeling by lipases, lipid transfer proteins and receptors. HDL exert several cardioprotective effects, through their antioxidant and antiinflammatory capacities and through the stimulation of reverse cholesterol transport from extrahepatic tissues to the liver for excretion into bile. HDL also serve as plasma reservoir for C and E apolipoproteins, as transport vehicles for a great variety of proteins, and may have more physiological functions than previously recognized. In this review we will develop several aspects of HDL metabolism with emphasis on the structure/function of apo A-I and apo A-II. An important contribution to our understanding of the respective roles of apo A-I and apo A-II comes from studies using transgenic animal models that highlighted the stabilizatory role of apo A-II on HDL through inhibition of their remodeling by lipases. Clinical studies coupled with proteomic analyses revealed the presence of dysfunctional HDL in patients with cardiovascular disease. Beyond HDL cholesterol, a new notion is the functionality of HDL particles. In spite of abundant literature on HDL metabolic properties, a major question remains unanswered: which HDL particle(s) confer(s) protection against cardiovascular risk? PMID:24012775

  1. Apolipoprotein E, especially apolipoprotein E4, increases the oligomerization of amyloid β peptide.

    PubMed

    Hashimoto, Tadafumi; Serrano-Pozo, Alberto; Hori, Yukiko; Adams, Kenneth W; Takeda, Shuko; Banerji, Adrian Olaf; Mitani, Akinori; Joyner, Daniel; Thyssen, Diana H; Bacskai, Brian J; Frosch, Matthew P; Spires-Jones, Tara L; Finn, Mary Beth; Holtzman, David M; Hyman, Bradley T

    2012-10-24

    Alzheimer's disease (AD) is the most common progressive neurodegenerative disorder causing dementia. Massive deposition of amyloid β peptide (Aβ) as senile plaques in the brain is the pathological hallmark of AD, but oligomeric, soluble forms of Aβ have been implicated as the synaptotoxic component. The apolipoprotein E ε 4 (apoE ε4) allele is known to be a genetic risk factor for developing AD. However, it is still unknown how apoE impacts the process of Aβ oligomerization. Here, we found that the level of Aβ oligomers in APOE ε4/ε4 AD patient brains is 2.7 times higher than those in APOE ε3/ε3 AD patient brains, matched for total plaque burden, suggesting that apoE4 impacts the metabolism of Aβ oligomers. To test this hypothesis, we examined the effect of apoE on Aβ oligomer formation. Using both synthetic Aβ and a split-luciferase method for monitoring Aβ oligomers, we observed that apoE increased the level of Aβ oligomers in an isoform-dependent manner (E2 < E3 < E4). This effect appears to be dependent on the ApoE C-terminal domain. Moreover, these results were confirmed using endogenous apoE isolated from the TBS-soluble fraction of human brain, which increased the formation of Aβ oligomers. Together, these data show that lipidated apoE, especially apoE4, increases Aβ oligomers in the brain. Higher levels of Aβ oligomers in the brains of APOE ε4/ε4 carriers compared with APOE ε3/ε3 carriers may increase the loss of dendritic spines and accelerate memory impairments, leading to earlier cognitive decline in AD.

  2. Mapping Fishing Effort through AIS Data.

    PubMed

    Natale, Fabrizio; Gibin, Maurizio; Alessandrini, Alfredo; Vespe, Michele; Paulrud, Anton

    2015-01-01

    Several research initiatives have been undertaken to map fishing effort at high spatial resolution using the Vessel Monitoring System (VMS). An alternative to the VMS is represented by the Automatic Identification System (AIS), which in the EU became compulsory in May 2014 for all fishing vessels of length above 15 meters. The aim of this paper is to assess the uptake of the AIS in the EU fishing fleet and the feasibility of producing a map of fishing effort with high spatial and temporal resolution at European scale. After analysing a large AIS dataset for the period January-August 2014 and covering most of the EU waters, we show that AIS was adopted by around 75% of EU fishing vessels above 15 meters of length. Using the Swedish fleet as a case study, we developed a method to identify fishing activity based on the analysis of individual vessels' speed profiles and produce a high resolution map of fishing effort based on AIS data. The method was validated using detailed logbook data and proved to be sufficiently accurate and computationally efficient to identify fishing grounds and effort in the case of trawlers, which represent the largest portion of the EU fishing fleet above 15 meters of length. Issues still to be addressed before extending the exercise to the entire EU fleet are the assessment of coverage levels of the AIS data for all EU waters and the identification of fishing activity in the case of vessels other than trawlers. PMID:26098430

  3. Mapping Fishing Effort through AIS Data

    PubMed Central

    Natale, Fabrizio; Gibin, Maurizio; Alessandrini, Alfredo; Vespe, Michele; Paulrud, Anton

    2015-01-01

    Several research initiatives have been undertaken to map fishing effort at high spatial resolution using the Vessel Monitoring System (VMS). An alternative to the VMS is represented by the Automatic Identification System (AIS), which in the EU became compulsory in May 2014 for all fishing vessels of length above 15 meters. The aim of this paper is to assess the uptake of the AIS in the EU fishing fleet and the feasibility of producing a map of fishing effort with high spatial and temporal resolution at European scale. After analysing a large AIS dataset for the period January-August 2014 and covering most of the EU waters, we show that AIS was adopted by around 75% of EU fishing vessels above 15 meters of length. Using the Swedish fleet as a case study, we developed a method to identify fishing activity based on the analysis of individual vessels’ speed profiles and produce a high resolution map of fishing effort based on AIS data. The method was validated using detailed logbook data and proved to be sufficiently accurate and computationally efficient to identify fishing grounds and effort in the case of trawlers, which represent the largest portion of the EU fishing fleet above 15 meters of length. Issues still to be addressed before extending the exercise to the entire EU fleet are the assessment of coverage levels of the AIS data for all EU waters and the identification of fishing activity in the case of vessels other than trawlers. PMID:26098430

  4. Apo A-I inhibits foam cell formation in apo E–deficient mice after monocyte adherence to endothelium

    PubMed Central

    Dansky, Hayes M.; Charlton, Sherri A.; Barlow, Courtenay B.; Tamminen, Minna; Smith, Jonathan D.; Frank, Joy S.; Breslow, Jan L.

    1999-01-01

    We have previously shown that expression of the human apo A-I transgene on the apo E–deficient background increases HDL cholesterol and greatly diminishes fatty streak lesion formation. To examine the mechanism, prelesional events in atherosclerotic plaque development were examined in 6- to 8-week-old apo E–deficient and apo E–deficient/human apo A-I transgenic mice. A quantitative assessment of subendothelial lipid deposition by freeze-fracture and deep-etch electron microscopy indicated that elevated apo A-I did not affect the distribution or amount of aortic arch subendothelial lipid deposits. Immunohistochemical staining for VCAM-1 demonstrated similar expression on endothelial cells at prelesional aortic branch sites from both apo E–deficient and apo E–deficient/human apo A-I transgenic mice. Transmission electron microscopy revealed monocytes bound to the aortic arch in mice of both genotypes, and immunohistochemical staining demonstrated that the area occupied by bound mononuclear cells was unchanged. Serum paraoxonase and aryl esterase activity did not differ between apo E–deficient and apo E–deficient/human apo A-I transgenic mice. These data suggest that increases in apo A-I and HDL cholesterol inhibit foam cell formation in apo E–deficient/human apo A-I transgenic mice at a stage following lipid deposition, endothelial activation, and monocyte adherence, without increases in HDL-associated paraoxonase. PMID:10393696

  5. The Structure of Dimeric Apolipoprotein A-IV and Its Mechanism of Self-Association

    SciTech Connect

    Deng, Xiaodi; Morris, Jamie; Dressmen, James; Tubb, Matthew R.; Tso, Patrick; Jerome, W. Gray; Davidson, W. Sean; Thompson, Thomas B.

    2012-08-10

    Apolipoproteins are key structural elements of lipoproteins and critical mediators of lipid metabolism. Their detergent-like properties allow them to emulsify lipid or exist in a soluble lipid-free form in various states of self-association. Unfortunately, these traits have hampered high-resolution structural studies needed to understand the biogenesis of cardioprotective high-density lipoproteins (HDLs). We derived a crystal structure of the core domain of human apolipoprotein (apo)A-IV, an HDL component and important mediator of lipid absorption. The structure at 2.4 {angstrom} depicts two linearly connected 4-helix bundles participating in a helix swapping arrangement that offers a clear explanation for how the protein self-associates as well as clues to the structure of its monomeric form. This also provides a logical basis for antiparallel arrangements recently described for lipid-containing particles. Furthermore, we propose a 'swinging door' model for apoA-IV lipid association.

  6. Francisella tularensis subsp. tularensis Group A.I, United States

    PubMed Central

    Birdsell, Dawn N.; Johansson, Anders; Öhrman, Caroline; Kaufman, Emily; Molins, Claudia; Pearson, Talima; Gyuranecz, Miklós; Naumann, Amber; Vogler, Amy J.; Myrtennäs, Kerstin; Larsson, Pär; Forsman, Mats; Sjödin, Andreas; Gillece, John D.; Schupp, James; Petersen, Jeannine M.; Keim, Paul

    2014-01-01

    We used whole-genome analysis and subsequent characterization of geographically diverse strains using new genetic signatures to identify distinct subgroups within Francisella tularensis subsp. tularensis group A.I: A.I.3, A.I.8, and A.I.12. These subgroups exhibit complex phylogeographic patterns within North America. The widest distribution was observed for A.I.12, which suggests an adaptive advantage. PMID:24755401

  7. Interferon-γ Protects from Staphylococcal Alpha Toxin-Induced Keratinocyte Death through Apolipoprotein L1.

    PubMed

    Brauweiler, Anne M; Goleva, Elena; Leung, Donald Y M

    2016-03-01

    Staphylococcus aureus is a bacterial pathogen that frequently infects the skin, causing lesions and cell destruction through its primary virulence factor, alpha toxin. Here we show that interferon gamma (IFN-?) protects human keratinocytes from cell death induced by staphylococcal alpha toxin. We find that IFN-? prevents alpha toxin binding and reduces expression of the alpha toxin receptor, a disintegrin and metalloproteinase 10 (ADAM10). We determine that the mechanism for IFN-?-mediated resistance to alpha toxin involves the induction of autophagy, a process of cellular adaptation to sublethal damage. We find that IFN-? potently stimulates activation of the primary autophagy effector, light chain 3 (LC3). This process is dependent on upregulation of apolipoprotein L1. Depletion of apolipoprotein L1 by small interfering RNA significantly increases alpha toxin-induced lethality and inhibits activation of light chain 3. We conclude that IFN-? plays a significant role in protecting human keratinocytes from the lethal effects of staphylococcal alpha toxin through apolipoprotein L1-induced autophagy.

  8. A role for apolipoprotein E, apolipoprotein A-I, and low density lipoprotein receptors in cholesterol transport during regeneration and remyelination of the rat sciatic nerve.

    PubMed Central

    Boyles, J K; Zoellner, C D; Anderson, L J; Kosik, L M; Pitas, R E; Weisgraber, K H; Hui, D Y; Mahley, R W; Gebicke-Haerter, P J; Ignatius, M J

    1989-01-01

    Recent work has demonstrated that apo E secretion and accumulation increase in the regenerating peripheral nerve. The fact that apoE, in conjunction with apoA-I and LDL receptors, participates in a well-established lipid transfer system raised the possibility that apoE is also involved in lipid transport in the injured nerve. In the present study of the crushed rat sciatic nerve, a combination of techniques was used to trace the cellular associations of apoE, apoA-I, and the LDL receptor during nerve repair and to determine the distribution of lipid at each stage. After a crush injury, as axons died and Schwann cells reabsorbed myelin, resident and monocyte-derived macrophages produced large quantities of apoE distal to the injury site. As axons regenerated in the first week, their tips contained a high concentration of LDL receptors. After axon regeneration, apoE and apoA-I began to accumulate distal to the injury site and macrophages became increasingly cholesterol-loaded. As remyelination began in the second and third weeks after injury, Schwann cells exhausted their cholesterol stores, then displayed increased LDL receptors. Depletion of macrophage cholesterol stores followed over the next several weeks. During this stage of regeneration, apoE and apoA-I were present in the extracellular matrix as components of cholesterol-rich lipoproteins. Our results demonstrate that the regenerating peripheral nerve possesses the components of a cholesterol transfer mechanism, and the sequence of events suggests that this mechanism supplies the cholesterol required for rapid membrane biogenesis during axon regeneration and remyelination. Images PMID:2493483

  9. Cacao polyphenols influence the regulation of apolipoprotein in HepG2 and Caco2 cells.

    PubMed

    Yasuda, Akiko; Natsume, Midori; Osakabe, Naomi; Kawahata, Keiko; Koga, Jinichiro

    2011-02-23

    Cocoa powder is rich in polyphenols, such as catechins and procyanidins, and has been shown to inhibit low-density lipoprotein (LDL) oxidation and atherogenesis in a variety of models. Human studies have also shown daily intake of cocoa increases plasma high-density lipoprotein (HDL) and decreases LDL levels. However, the mechanisms responsible for these effects of cocoa on cholesterol metabolism have yet to be fully elucidated. The present study investigated the effects of cacao polyphenols on the production of apolipoproteins A1 and B in human hepatoma HepG2 and intestinal Caco2 cell lines. The cultured HepG2 cells or Caco2 cells were incubated for 24 h in the presence of cacao polyphenols such as (-)-epicatechin, (+)-catechin, procyanidin B2, procyanidin C1, and cinnamtannin A2. The concentration of apolipoproteins in the cell culture media was quantified using an enzyme-linked immunoassay, and the mRNA expression was quantified by RT-PCR. Cacao polyphenols increased apolipoprotein A1 protein levels and mRNA expression, even though apolipoprotein B protein and the mRNA expression were slightly decreased in both HepG2 cells and Caco2 cells. In addition, cacao polyphenols increased sterol regulatory element binding proteins (SREBPs) and activated LDL receptors in HepG2 cells. These results suggest that cacao polyphenols may increase the production of mature form SREBPs and LDL receptor activity, thereby increasing ApoA1 and decreasing ApoB levels. These results elucidate a novel mechanism by which HDL cholesterol levels become elevated with daily cocoa intake.

  10. Comparison of AIS 1990 update 98 versus AIS 2005 for describing PMHS injuries in lateral and oblique sled tests

    PubMed Central

    Yoganandan, Narayan; Pintar, Frank A.; Humm, John R.; Stadter, Gregory W.; Curry, William H.; Brasel, Karen J.

    2013-01-01

    This study analyzed skeletal and organ injuries in pure lateral and oblique impacts from 20 intact post mortem human surrogate (PMHS) sled tests at 6.7 m/s. Injuries to the shoulder, thorax, abdomen, pelvis and spine were scored using AIS 1990–1998 update and 2005. The Injury Severity Scores (ISS) were extracted for both loadings from both versions. Mean age, stature, total body mass and body mass index for pure lateral and oblique tests: 58 and 55 years, 1.7 and 1.8 m, 69 and 66 kg, and 24 and 21 kg/m2. Skeletal injuries (ribs, sternum) occurred in both impacts. However, oblique impacts resulted in more injuries. Pure lateral and oblique impacts ISS: 0 to 16 and 0 to 24, representing a greater potential for injury-related consequences in real-world situations in oblique impacts. Internal organs were more involved in oblique impacts. ISS decreased in AIS 2005, reflecting changes to scoring and drawing attention to potential effects for pre-hospital care/medical aspects. Mean AIS scores for the two load vectors and two AIS coding schemes are included. From automotive crashworthiness perspectives, decreases in injury severities might alter injury risk functions with a shift to lower metrics for the same risk level than current risk estimations. This finding influences dummy-based injury criteria and occupant safety as risk functions are used for countermeasure effectiveness and cost-benefit analyses by regulatory bodies. Increase in organ injuries in oblique loading indicate the importance of this vector as current dummies and injury criteria used in regulations are based on pure lateral impact data. PMID:24406958

  11. Role of urea on recombinant Apo A-I stability and its utilization in anion exchange chromatography.

    PubMed

    Angarita, Monica; Arosio, Paolo; Müller-Späth, Thomas; Baur, Daniel; Falkenstein, Roberto; Kuhne, Wolfgang; Morbidelli, Massimo

    2014-08-01

    Apolipoprotein A-I (Apo A-I) is an important lipid-binding protein involved in the transport and metabolism of cholesterol. High protein purity, in particular with respect to endotoxins is required for therapeutic applications. The use of urea during the purification process of recombinant Apo A-I produced in Escherichia coli has been suggested so as to provide high endotoxin clearance. In this work, we show that urea can be used as a sole modifier during the ion exchange chromatographic purification of Apo A-I and we investigate the molecular mechanism of elution by correlating the effect of urea on self-association, conformation and adsorption equilibrium properties of a modified model Apo A-I. In the absence of urea the protein was found to be present as a population of oligomers represented mainly by trimers, hexamers and nonamers. The addition of urea induced oligomer dissociation and protein structure unfolding. We correlated the changes in protein association and conformation with variations of the adsorption equilibrium of the protein on a strong anion exchanger. It was confirmed that the adsorption isotherms, described by a Langmuir model, were dependent on both protein and urea concentrations. Monomers, observed at low urea concentration (0.5M), were characterized by larger binding affinity and adsorption capacity compared to both protein oligomers (0M) and unfolded monomers (2-8M). The reduction of both the binding strength and maximum adsorption capacity at urea concentrations larger than 0.5M explains the ability of urea of inducing elution of the protein from the ion exchange resin. The dissociation of the protein complexes occurring during the elution could likely be the origin of the effective clearance of endotoxins originally trapped inside the oligomers.

  12. New apolipoprotein A-V: comparative genomics meets metabolism.

    PubMed

    Seda, O; Sedová, L

    2003-01-01

    The availability of the human genome sequence and the recently completed draft sequences of two major mammalian model species, the mouse (Mus musculus) and the rat (Rattus norvegicus), allow researchers to apply novel approaches for gene identification and characterization, using methods of comparative and functional genomics. Recently, a new gene coding for apolipoprotein A-V was identified in the vicinity of APOA-I/C-III/A-IV cluster on human chromosome 11q23 by comparative sequencing method. In a relatively short time, compelling evidence accumulated for the substantial role of APOA-V in lipid metabolism. Studies in knock-out and transgenic mice revealed that its expression pattern correlates negatively with triglyceride levels. This observation was verified in human population studies in variety of ethnic and age groups. Several single nucleotide polymorphisms were described and particular SNP alleles and haplotypes in the APO A-V gene region were shown to be associated with dyslipidemia. The discovery and characterization of the APO A-V demonstrates current possibilities of the integrative approaches in biology, boosted by the available bioinformatic tools.

  13. Altered Plasma Apolipoprotein Modifications in Patients with Pancreatic Cancer: Protein Characterization and Multi-Institutional Validation

    PubMed Central

    Honda, Kazufumi; Okusaka, Takuji; Felix, Klaus; Nakamori, Shoji; Sata, Naohiro; Nagai, Hideo; Ioka, Tatsuya; Tsuchida, Akihiko; Shimahara, Takeshi; Shimahara, Masashi; Yasunami, Yohichi; Kuwabara, Hideya; Sakuma, Tomohiro; Otsuka, Yoshihiko; Ota, Norihito; Shitashige, Miki; Kosuge, Tomoo; Büchler, Markus W.; Yamada, Tesshi

    2012-01-01

    Background Among the more common human malignancies, invasive ductal carcinoma of the pancreas has the worst prognosis. The poor outcome seems to be attributable to difficulty in early detection. Methods We compared the plasma protein profiles of 112 pancreatic cancer patients with those of 103 sex- and age-matched healthy controls (Cohort 1) using a newly developed matrix-assisted laser desorption/ionization (oMALDI) QqTOF (quadrupole time-of-flight) mass spectrometry (MS) system. Results We found that hemi-truncated apolipoprotein AII dimer (ApoAII-2; 17252 m/z), unglycosylated apolipoprotein CIII (ApoCIII-0; 8766 m/z), and their summed value were significantly decreased in the pancreatic cancer patients [P = 1.36×10−21, P = 4.35×10−14, and P = 1.83×10−24 (Mann-Whitney U-test); area-under-curve values of 0.877, 0.798, and 0.903, respectively]. The significance was further validated in a total of 1099 plasma/serum samples, consisting of 2 retrospective cohorts [Cohort 2 (n = 103) and Cohort 3 (n = 163)] and a prospective cohort [Cohort 4 (n = 833)] collected from 8 medical institutions in Japan and Germany. Conclusions We have constructed a robust quantitative MS profiling system and used it to validate alterations of modified apolipoproteins in multiple cohorts of patients with pancreatic cancer. PMID:23056525

  14. Purification and Characterization of BmooAi: A New Toxin from Bothrops moojeni Snake Venom That Inhibits Platelet Aggregation

    PubMed Central

    Ribeiro de Queiroz, Mayara; Mamede, Carla Cristine N.; de Morais, Nadia Cristina G.; Cortes Fonseca, Kelly; Barbosa de Sousa, Bruna; Migliorini, Thaís M.; Pereira, Déborah Fernanda C.; Stanziola, Leonilda; Calderon, Leonardo A.; Simões-Silva, Rodrigo; Martins Soares, Andreimar; de Oliveira, Fábio

    2014-01-01

    In this paper, we describe the purification/characterization of BmooAi, a new toxin from Bothrops moojeni that inhibits platelet aggregation. The purification of BmooAi was carried out through three chromatographic steps (ion-exchange on a DEAE-Sephacel column, molecular exclusion on a Sephadex G-75 column, and reverse-phase HPLC chromatography on a C2/C18 column). BmooAi was homogeneous by SDS-PAGE and shown to be a single-chain protein of 15,000 Da. BmooAi was analysed by MALDI-TOF Spectrometry and revealed two major components with molecular masses 7824.4 and 7409.2 as well as a trace of protein with a molecular mass of 15,237.4 Da. Sequencing of BmooAi by Edman degradation showed two amino acid sequences: IRDFDPLTNAPENTA and ETEEGAEEGTQ, which revealed no homology to any known toxin from snake venom. BmooAi showed a rather specific inhibitory effect on platelet aggregation induced by collagen, adenosine diphosphate, or epinephrine in human platelet-rich plasma in a dose-dependent manner, whereas it had little or no effect on platelet aggregation induced by ristocetin. The effect on platelet aggregation induced by BmooAi remained active even when heated to 100°C. BmooAi could be of medical interest as a new tool for the development of novel therapeutic agents for the prevention and treatment of thrombotic disorders. PMID:24971359

  15. Using AI to understand key success features in evolving CTSAs.

    PubMed

    Kusch, Jennifer D; Nelson, David A; Simpson, Deborah; Gerrits, Ronald; Glass, Laurie

    2013-08-01

    A vital role for Clinical and Translational Science Award (CTSA) evaluators is to first identify and then articulate the necessary change processes that support the research infrastructures and achieve synergies needed to improve health through research. The use of qualitative evaluation strategies to compliment quantitative tracking measures (e.g., number of grants/publications) is an essential but under-utilized approach in CTSA evaluations. The Clinical and Translational Science Institute of Southeast Wisconsin implemented a qualitative evaluation approach using appreciative inquiry (AI) that has revealed three critical features associated with CTSA infrastructure transformation success: developing open communication, creating opportunities for proactive collaboration, and ongoing attainment of milestones at the key function group level. These findings are consistent with Bolman & Deal's four interacting hallmarks of successful organizations: structural (infrastructure), political (power distribution; organizational politics), human resource (facilitating change among humans necessary for continued success), and symbolic (visions and aspirations). Data gathered through this longitudinal AI approach illuminates how these change features progress over time as CTSA funded organizations successfully create the multiinstitutional infrastructures to connect laboratory discoveries with the diagnosis and treatment of human disease.

  16. Apolipoprotein D in Lipid Metabolism and Its Functional Implication in Atherosclerosis and Aging

    PubMed Central

    Perdomo, German; Dong, H. Henry

    2009-01-01

    Dyslipidemia is characterized by increased triglyceride and low-density lipoprotein (LDL) levels, and decreased high-density lipoprotein (HDL) levels. Such an atherogenic lipid profile often predisposes an at risk individual to coronary artery disease with incompletely understood mechanisms. Apolipoprotein D (apoD) is an atypical apolipoprotein. Unlike canonical apolipoproteins that are produced mainly in liver and intestine, apoD is expressed widely in mammalian tissues. ApoD does not share significant degrees of homology in amino acid sequence with other apolipoproteins. Instead, apoD is structurally similar to lipocalins, a diverse family of lipid-binding proteins that are responsible for transporting lipids and other small hydrophobic molecules for metabolism. Plasma ApoD is present mainly in HDL and to a lesser extent in low density lipoproteins (LDL) and very low-density lipoproteins (VLDL). Genetic variants of apoD are associated with abnormal lipid metabolism and increased risk of developing metabolic syndrome. Increased apoD deposition is detectable in atherosclerotic lesions of humans with established cardiovascular disease as well as mice with premature atherosclerosis. Moreover, apoD is associated with anti-oxidation and anti-stress activities, contributing to lifespan expansion in fruit flies. Elderly subjects and patients with Alzheimer exhibit markedly elevated apoD production in the brain. Thus, apoD is emerged as a significant player in lipid metabolism and aging. Here we focus our review on recent advances toward our understanding of apoD in lipid metabolism and address whether apoD dysregulation contributes to the pathogenesis of dyslipidemia and atherosclerosis. We will also discuss the functional implication of apoD in aging. PMID:19946382

  17. Applying AI to the Writer's Learning Environment.

    ERIC Educational Resources Information Center

    Houlette, Forrest

    1991-01-01

    Discussion of current applications of artificial intelligence (AI) to writing focuses on how to represent knowledge of the writing process in a way that links procedural knowledge to other types of knowledge. A model is proposed that integrates the subtasks of writing into the process of writing itself. (15 references) (LRW)

  18. Peroxisome proliferator-activated receptorα agonists differentially regulate inhibitor of DNA binding expression in rodents and human cells.

    PubMed

    González, María Del Carmen; Corton, J Christopher; Acero, Nuria; Muñoz-Mingarro, Dolores; Quirós, Yolanda; Alvarez-Millán, Juan José; Herrera, Emilio; Bocos, Carlos

    2012-01-01

    Inhibitor of DNA binding (Id2) is a helix-loop-helix (HLH) transcription factor that participates in cell differentiation and proliferation. Id2 has been linked to the development of cardiovascular diseases since thiazolidinediones, antidiabetic agents and peroxisome proliferator-activated receptor (PPAR) gamma agonists, have been reported to diminish Id2 expression in human cells. We hypothesized that PPARα activators may also alter Id2 expression. Fenofibrate diminished hepatic Id2 expression in both late pregnant and unmated rats. In 24 hour fasted rats, Id2 expression was decreased under conditions known to activate PPARα. In order to determine whether the fibrate effects were mediated by PPARα, wild-type mice and PPARα-null mice were treated with Wy-14,643 (WY). WY reduced Id2 expression in wild-type mice without an effect in PPARα-null mice. In contrast, fenofibrate induced Id2 expression after 24 hours of treatment in human hepatocarcinoma cells (HepG2). MK-886, a PPARα antagonist, did not block fenofibrate-induced activation of Id2 expression, suggesting a PPARα-independent effect was involved. These findings confirm that Id2 is a gene responsive to PPARα agonists. Like other genes (apolipoprotein A-I, apolipoprotein A-V), the opposite directional transcriptional effect in rodents and a human cell line further emphasizes that PPARα agonists have different effects in rodents and humans.

  19. Peroxisome Proliferator-Activated Receptorα Agonists Differentially Regulate Inhibitor of DNA Binding Expression in Rodents and Human Cells

    PubMed Central

    González, María del Carmen; Corton, J. Christopher; Acero, Nuria; Muñoz-Mingarro, Dolores; Quirós, Yolanda; Álvarez-Millán, Juan José; Herrera, Emilio; Bocos, Carlos

    2012-01-01

    Inhibitor of DNA binding (Id2) is a helix-loop-helix (HLH) transcription factor that participates in cell differentiation and proliferation. Id2 has been linked to the development of cardiovascular diseases since thiazolidinediones, antidiabetic agents and peroxisome proliferator-activated receptor (PPAR) gamma agonists, have been reported to diminish Id2 expression in human cells. We hypothesized that PPARα activators may also alter Id2 expression. Fenofibrate diminished hepatic Id2 expression in both late pregnant and unmated rats. In 24 hour fasted rats, Id2 expression was decreased under conditions known to activate PPARα. In order to determine whether the fibrate effects were mediated by PPARα, wild-type mice and PPARα-null mice were treated with Wy-14,643 (WY). WY reduced Id2 expression in wild-type mice without an effect in PPARα-null mice. In contrast, fenofibrate induced Id2 expression after 24 hours of treatment in human hepatocarcinoma cells (HepG2). MK-886, a PPARα antagonist, did not block fenofibrate-induced activation of Id2 expression, suggesting a PPARα-independent effect was involved. These findings confirm that Id2 is a gene responsive to PPARα agonists. Like other genes (apolipoprotein A-I, apolipoprotein A-V), the opposite directional transcriptional effect in rodents and a human cell line further emphasizes that PPARα agonists have different effects in rodents and humans. PMID:22701468

  20. Data on gene and protein expression changes induced by apabetalone (RVX-208) in ex vivo treated human whole blood and primary hepatocytes.

    PubMed

    Wasiak, Sylwia; Gilham, Dean; Tsujikawa, Laura M; Halliday, Christopher; Norek, Karen; Patel, Reena G; McLure, Kevin G; Young, Peter R; Gordon, Allan; Kulikowski, Ewelina; Johansson, Jan; Sweeney, Michael; Wong, Norman C

    2016-09-01

    Apabetalone (RVX-208) inhibits the interaction between epigenetic regulators known as bromodomain and extraterminal (BET) proteins and acetyl-lysine marks on histone tails. Data presented here supports the manuscript published in Atherosclerosis "RVX-208, a BET-inhibitor for Treating Atherosclerotic Cardiovascular Disease, Raises ApoA-I/HDL and Represses Pathways that Contribute to Cardiovascular Disease" (Gilham et al., 2016) [1]. It shows that RVX-208 and a comparator BET inhibitor (BETi) JQ1 increase mRNA expression and production of apolipoprotein A-I (ApoA-I), the main protein component of high density lipoproteins, in primary human and African green monkey hepatocytes. In addition, reported here are gene expression changes from a microarray-based analysis of human whole blood and of primary human hepatocytes treated with RVX-208. PMID:27570805

  1. Ledipasvir/sofosbuvir treatment of hepatitis C virus is associated with reduction in serum apolipoprotein levels.

    PubMed

    Younossi, Z M; Elsheikh, E; Stepanova, M; Gerber, L; Nader, F; Stamm, L M; Brainard, D M; McHutchinson, J G

    2015-12-01

    The interaction of lipoproteins with hepatitis C virus (HCV) has pathogenic and therapeutic implications. Our aim was to evaluate changes in the apolipoprotein profile of patients with chronic hepatitis C during and after successful cure with ledipasvir and sofosbuvir (LDV/SOF) with and without ribavirin (RBV). One hundred HCV genotype 1 patients who had achieved SVR-12 after treatment with 12 weeks of LDV/SOF ± RBV were selected from the ION-1 clinical trial. Frozen serum samples from baseline, end of treatment and week 4 of follow-up were used to assay apolipoproteins (apoAI, apoAII, apoB, apoCII, apoCIII, apoE) using the Multiplex platform to assess for changes in the apolipoprotein levels. At the end of treatment compared to baseline, a significant reduction in apoAII levels (-14.97 ± 63.44 μg/mL, P = 0.0067) and apoE levels (-4.38 ± 12.19 μg/mL, P < 0.001) was noted. These declines from baseline in apoAII (-16.59 ±66.15 μg/mL, P = 0.0075) and apoE (-2.66 ± 12.64 μg/mL, P = 0.015) persisted at 4 weeks of post-treatment follow-up. In multivariate analysis, treatment with LDV/SOF + RBV was independently associated with reduction in apoE (beta = 5.31 μg/mL, P = 0.002) (compared to RBV-free LDV/SOF) (P < 0.05). In contrast, apoCII levels overall increased from baseline to end of treatment (+2.74 ±11.76 μg/mL, P = 0.03) and persisted at 4 weeks of follow-up (+4.46 ± 12.81 μg/mL from baseline, P = 0.0005). Subgroup analysis revealed an increase in apoCII during treatment only in patients receiving LDV/SOF without RBV (+5.52 ± 11.92 μg/mL, P = 0.0007) but not in patients receiving LDV/SOF + RBV (P = 0.638). Treatment with LDV/SOF ± RBV is associated with a persistent reduction in the apolipoprotein AII and E after achieving cure. These data suggest that treatment with LDV/SOF ± RBV may be associated with alterations in serum apolipoproteins which could potentially impact viral eradication.

  2. Fertility of holstein dairy heifers after synchronization of ovulation and timed AI or AI after removed tail chalk.

    PubMed

    Rivera, H; Lopez, H; Fricke, P M

    2004-07-01

    Nonlactating Holstein dairy heifers (n=352) 13 mo of age were managed using a 42-d artificial insemination (AI) breeding period in which they received AI after removed tail chalk evaluated once daily. At AI breeding period onset (d 0), heifers were randomly assigned to receive synchronization of ovulation (100 microg of GnRH, d 0; 25 mg of PGF2alpha, d 6; 100 microg of GnRH, d 8) and timed AI (TAI; d 8) and AI after removed tail chalk for the entire AI breeding period (GPG; n=175), or AI after removed tail chalk for the entire AI breeding period (TC; n=177). As expected, 17.7% (31/175) of GPG heifers received AI after removed tail chalk before scheduled TAI. Pregnancy rate per artificial insemination (PR/AI) at approximately 30 d after first AI tended to be greater for TC (46.5%) than for GPG (38.3%) heifers. No treatment x inseminator interaction was detected; however, overall PR/AI was low for heifers in both treatments due to variation among the 3 inseminators (24.8, 30.0, and 58.0%). Pregnancy loss from approximately 30 to approximately 75 d after first AI was 10% and did not differ between treatments. Based on survival analysis, days to first AI was greater for TC than for GPG heifers, whereas days to pregnancy across the 42-d AI breeding period did not differ between treatments. Overall, 81.2% of GPG heifers receiving TAI synchronized luteal regression and ovulated within 48 h after the second GnRH injection. We conclude that this synchronization protocol can yield acceptable fertility in dairy heifers if AI to estrus is conducted between treatment with GnRH and PGF2alpha and AI efficiency is optimized. PMID:15328217

  3. Influence of infant and juvenile diets on serum cholesterol, lipoprotein cholesterol, and apolipoprotein concentrations in juvenile baboons (Papio sp.).

    PubMed

    Mott, G E; McMahan, C A; Kelley, J L; Farley, C M; McGill, H C

    1982-11-01

    The long-term effects of infant diet (breast milk or formula containing 2, 30, or 60 mg/dl cholesterol) and subsequent dietary cholesterol (1 mg/kcal) and fat (saturated or unsaturated) on serum lipid and apolipoprotein concentrations were estimated using 82 juvenile baboons 4-6 years of age. A significant interaction of infant diet (breast vs formula) with type of fat (saturated vs unsaturated) at 4-6 years of age was observed on HDL cholesterol and apolipoprotein A-I (apoA-I) concentrations. That is, animals breast-fed as infants had higher HDL cholesterol and apoA-I concentrations when fed unsaturated fat from weaning to 4-6 years of age than those fed saturated fat (77 vs 68 mg/dl). In contrast, animals fed formulas in infancy followed by a diet containing unsaturated fat had lower HDL cholesterol and apoA-I concentrations at 4-6 years of age than did those fed saturated fat (67 vs 78 mg/dl). However, breast feeding or feeding formulas containing various levels of cholesterol for 3 months during infancy did not result in statistically significant differences in total serum cholesterol, VLDL + LDL cholesterol and apolipoprotein B (apoB) concentrations. Dietary cholesterol after infancy significantly increased serum total cholesterol, VLDL + LDL and HDL cholesterol, apoA-I and apoB concentrations. All of these response variables also were higher in animals fed saturated fat compared to those fed unsaturated fat on the same level of cholesterol. At 4-6 years of age, regardless of diet, females had significantly higher serum VLDL + LDL cholesterol (57 vs 43 mg/dl) and apoB concentrations (39 vs 30 mg/dl) than did males.

  4. Characterization and functional properties of the alpha-amylase inhibitor (alpha-AI) from kidney bean (Phaseolus vulgaris) seeds.

    PubMed

    Le Berre-Anton, V; Bompard-Gilles, C; Payan, F; Rougé, P

    1997-11-14

    Alpha-amylase inhibitor (alpha-AI) from kidney bean (Phaseolus vulgaris L. cv Tendergreen) seeds has been purified to homogeneity by heat treatment in acidic medium, ammonium sulphate fractionation, chromatofocusing and gel filtration. Two isoforms, alpha-AI1 and alpha-AI1', of 43 kDa have been isolated which differ from each other by their isoelectric points and neutral sugar contents. The major isoform alpha-AI1 inhibited human and porcine pancreatic alpha-amylases (PPA) but was devoid of activity on alpha-amylases of bacterial or fungal origins. As shown on the Lineweaver-Burk plots, the nature of the inhibition is explained by a mixed non-competitive inhibition mechanism. Alpha-AI1 formed a 1:2 stoichiometric complex with PPA which showed an optimum pH of 4.5 at 30 degrees C. Owing to the low optimum pH found for alpha-AI activity, inhibitor-containing diets such as beans or transgenic plants expressing alpha-AI should be devoid of any harmful effect on human health. PMID:9428656

  5. AI in space: Past, present, and possible futures

    NASA Technical Reports Server (NTRS)

    Rose, Donald D.; Post, Jonathan V.

    1992-01-01

    While artificial intelligence (AI) has become increasingly present in recent space applications, new missions being planned will require even more incorporation of AI techniques. In this paper, we survey some of the progress made to date in implementing such programs, some current directions and issues, and speculate about the future of AI in space scenarios. We also provide examples of how thinkers from the realm of science fiction have envisioned AI's role in various aspects of space exploration.

  6. Why Don't Accounting Students like AIS?

    ERIC Educational Resources Information Center

    Vatanasakdakul, Savanid; Aoun, Chadi

    2011-01-01

    Purpose: The demand for Accounting Information Systems (AIS) knowledge has increased exponentially over the past two decades, but studying AIS has not proved easy for many accounting students. The aim of the study is to understand the challenges accounting students face in studying AIS through investigation of the factors which may be contributing…

  7. 47 CFR 80.393 - Frequencies for AIS stations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... requirements for non-Federal Government ships. These requirements are codified at 33 CFR 164.46, 401.20. ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Frequencies for AIS stations. 80.393 Section 80... STATIONS IN THE MARITIME SERVICES Frequencies Ais Stations § 80.393 Frequencies for AIS stations....

  8. The AI Interdisciplinary Context: Single or Multiple Research Bases?

    ERIC Educational Resources Information Center

    Khawam, Yves J.

    1992-01-01

    This study used citation analysis to determine whether the disciplines contributing to the journal literature of artificial intelligence (AI)--philosophy, psychology, linguistics, computer science, and engineering--share a common AI research base. The idea that AI consists of a completely interdisciplinary endeavor was refuted. (MES)

  9. In vivo efficacy of HDL-like nanolipid particles containing multivalent peptide mimetics of apolipoprotein A-I[S

    PubMed Central

    Zhao, Yannan; Black, Audrey S.; Bonnet, David J.; Maryanoff, Bruce E.; Curtiss, Linda K.; Leman, Luke J.; Ghadiri, M. Reza

    2014-01-01

    We have observed that molecular constructs based on multiple apoA-I mimetic peptides attached to a branched scaffold display promising anti-atherosclerosis functions in vitro. Building on these promising results, we now describe chronic in vivo studies to assess anti-atherosclerotic efficacy of HDL-like nanoparticles assembled from a trimeric construct, administered over 10 weeks either ip or orally to LDL receptor-null mice. When dosed ip, the trimer-based nanolipids markedly reduced plasma LDL-cholesterol levels by 40%, unlike many other apoA-I mimetic peptides, and were substantially atheroprotective. Surprisingly, these nanoparticles were also effective when administered orally at a dose of 75 mg/kg, despite the peptide construct being composed of l-amino acids and being undetectable in the plasma. The orally administered nanoparticles reduced whole aorta lesion areas by 55% and aortic sinus lesion volumes by 71%. Reductions in plasma cholesterol were due to the loss of non-HDL lipoproteins, while plasma HDL-cholesterol levels were increased. At a 10-fold lower oral dose, the nanoparticles were marginally effective in reducing atherosclerotic lesions. Intriguingly, analogous results were obtained with nanolipids of the corresponding monomeric peptide. These nanolipid formulations provide an avenue for developing orally efficacious therapeutic agents to manage atherosclerosis. PMID:24975585

  10. Extended-release niacin alters the metabolism of plasma apolipoprotein (apo) A-I- and apoB-containing lipoproteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extended-release niacin effectively lowers plasma TG levels and raises plasma HDL cholesterol levels, but the mechanisms responsible for these effects are unclear. We examined the effects of extended-release niacin (2 g/d) and extended-release niacin (2 g/d) plus lovastatin (40 mg/d), relative to pl...

  11. Molecular crowding impacts the structure of apolipoprotein A-I with potential implications on in vivo metabolism and function.

    PubMed

    Petrlova, Jitka; Hilt, Silvia; Budamagunta, Madhu; Domingo-Espín, Joan; Voss, John C; Lagerstedt, Jens O

    2016-10-01

    The effect molecular crowding, defined as the volume exclusion exerted by one soluble inert molecule upon another soluble molecule, has on the structure and self-interaction of lipid-free apoA-I were explored. The influence of molecular crowding on lipid-free apoA-I oligomerization and internal dynamics has been analyzed using electron paramagnetic resonance (EPR) spectroscopy measurements of nitroxide spin label at selected positions throughout the protein sequence and at varying concentrations of the crowding agent Ficoll-70. The targeted positions include sites previously shown to be sensitive for detecting intermolecular interaction via spin-spin coupling. Circular dichroism was used to study secondary structural changes in lipid-free apoA-I imposed by increasing concentrations of the crowding agent. Crosslinking and SDS-PAGE gel analysis was employed to further characterize the role molecular crowding plays in inducing apoA-I oligomerization. It was concluded that the dynamic apoA-I structure and oligomeric state was altered in the presence of the crowding agent. It was also found that the C-terminal was slightly more sensitive to molecular crowding. Finally, the data described the region around residue 217 in the C-terminal domain of apoA-I as the most sensitive reporter of the crowding-induced self-association of apoA-I. The implications of this behavior to in vivo functionality are discussed. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 683-692, 2016.

  12. Role of Apolipoprotein E in β-Amyloidogenesis

    PubMed Central

    Hori, Yukiko; Hashimoto, Tadafumi; Nomoto, Hidetoshi; Hyman, Bradley T.; Iwatsubo, Takeshi

    2015-01-01

    Human APOE ϵ4 allele is a strong genetic risk factor of Alzheimer disease. Neuropathological and genetic studies suggested that apolipoprotein E4 (apoE4) protein facilitates deposition of amyloid β peptide (Aβ) in the brain, although the mechanism whereby apoE4 increases amyloid aggregates remains elusive. Here we show that injection of Aβ protofibrils induced Aβ deposition in the brain of APP transgenic mice, suggesting that Aβ protofibrils acted as a seed for aggregation and deposition of Aβ in vivo. Injection of Aβ protofibrils together with apoE3 significantly attenuated Aβ deposition, whereas apoE4 did not have this effect. In vitro assays revealed that the conversion of Aβ protofibrils to fibrils progressed more slowly upon coincubation with apoE2 or apoE3 compared with that with apoE4. Aβ protofibrils complexed with apoE4 were less stable than those with apoE2 or apoE3. These data suggest that the suppression effect of apoE2 or apoE3 on the structural conversion of Aβ protofibrils to fibrils is stronger than those of apoE4, thereby impeding β-amyloid deposition. PMID:25918154

  13. The potential applications of Apolipoprotein E in personalized medicine

    PubMed Central

    Villeneuve, Sylvia; Brisson, Diane; Marchant, Natalie L.; Gaudet, Daniel

    2014-01-01

    Personalized medicine uses various individual characteristics to guide medical decisions. Apolipoprotein (ApoE), the most studied polymorphism in humans, has been associated with several diseases. The purpose of this review is to elucidate the potential role of ApoE polymorphisms in personalized medicine, with a specific focus on neurodegenerative diseases, by giving an overview of its influence on disease risk assessment, diagnosis, prognosis, and therapy. This review is not a systematic inventory of the literature, but rather a summary and discussion of novel, influential and promising works in the field of ApoE research that could be valuable for personalized medicine. Empirical evidence suggests that ApoE genotype informs pre-symptomatic risk for a wide variety of diseases, is valuable for the diagnosis of type III dysbetalipoproteinemia, increases risk of dementia in neurodegenerative diseases, and is associated with a poor prognosis following acute brain damage. ApoE status appears to influence the efficacy of certain drugs, outcome of clinical trials, and might also give insight into disease prevention. Assessing ApoE genotype might therefore help to guide medical decisions in clinical practice. PMID:25071563

  14. Glucose Regulates the Expression of the Apolipoprotein A5 Gene

    SciTech Connect

    Fruchart, Jamila; Nowak, Maxime; Helleboid-Chapman, Audrey; Jakel, Heidelinde; Moitrot, Emmanuelle; Rommens, Corinne; Pennacchio, Len A.; Fruchart-Najib, Jamila; Fruchart, Jean-Charles

    2008-04-07

    The apolipoprotein A5 gene (APOA5) is a key player in determining triglyceride concentrations in humans and mice. Since diabetes is often associated with hypertriglyceridemia, this study explores whether APOA5 gene expression is regulated by alteration in glucose homeostasis and the related pathways. D-glucose activates APOA5 gene expression in a time- and dose-dependent manner in hepatocytes, and the glycolytic pathway involved was determined using D-glucose analogs and metabolites. Together, transient transfections, electrophoretic mobility shift assays and chromatin immunoprecipitation assays show that this regulation occurs at the transcriptional level through an increase of USF1/2 binding to an E-box in the APOA5 promoter. We show that this phenomenon is not due to an increase of mRNA or protein expression levels of USF. Using protein phosphatases 1 and 2A inhibitor, we demonstrate that D-glucose regulates APOA5 gene via a dephosphorylation mechanism, thereby resulting in an enhanced USF1/2-promoter binding. Last, subsequent suppressions of USF1/2 and phosphatases mRNA through siRNA gene silencing abolished the regulation. We demonstrate that APOA5 gene is up regulated by D-glucose and USF through phosphatase activation. These findings may provide a new cross talk between glucose and lipid metabolism.

  15. Transgenic Drosophila model to study apolipoprotein E4-induced neurodegeneration.

    PubMed

    Haddadi, Mohammad; Nongthomba, Upendra; Jahromi, Samaneh Reiszadeh; Ramesh, S R

    2016-03-15

    The ε4 isoform of apolipoprotein E (ApoE4) that is involved in neuron-glial lipid metabolism has been demonstrated as the main genetic risk factor in late-onset of Alzheimer's disease. However, the mechanism underlying ApoE4-mediated neurodegeneration remains unclear. We created a transgenic model of neurodegenerative disorder by expressing ε3 and ε4 isoforms of human ApoE in the Drosophila melanogaster. The genetic models exhibited progressive neurodegeneration, shortened lifespan and memory impairment. Genetic interaction studies between amyloid precursor protein and ApoE in axon pathology of the disease revealed that over expression of hApoE in Appl-expressing neurons of Drosophila brain causes neurodegeneration. Moreover, acute oxidative damage in the hApoE transgenic flies triggered a neuroprotective response of hApoE3 while chronic induction of oxidative damage accelerated the rate of neurodegeneration. This Drosophila model may facilitate analysis of the molecular and cellular events implicated in hApoE4 neurotoxicity.

  16. Autonomous vehicle control using AI techniques

    SciTech Connect

    Keirsey, D.; Mitchell, J.; Bullock, B.; Nussmeier, T.; Tseng, D.

    1983-11-01

    A review of early work on a project for developing autonomous vehicle control technology is presented. The primary goal of this effort is the development of a generic capability that can be specialized to a wide range of DOD applications. Project emphasis is on development of the fundamental AI-based technology required by autonomous systems and the implementation of a testbed environment to evaluate and demonstrate the system capabilities. 10 references.

  17. Association of carotid intima-media thickness with leptin and apoliprotein b/apoliprotein a-I ratio reveals imminent predictors of subclinical atherosclerosis in psoriasis patients.

    PubMed

    Asha, Kumari; Sharma, Suman B; Singal, Archana; Aggarwal, Amitesh

    2014-01-01

    Psoriasis patients are often susceptible to cardiovascular diseases (CVD), including atherosclerosis. Traditional markers (biochemical and inflammatory) and diagnostic tools could detect occlusive but not subclinical atherosclerosis. Carotid intima-media thickness (CIMT), has recently been recognised as a non invasive diagnostic tool for identification of premature atherosclerosis. Therefore we evaluated 80 psoriasis patients and 80 age sex matched healthy controls for serum leptin levels and apolipoprotein B/apolipoprotein A-I ratio (apoB/apoA-I ratio) in relation with CIMT of carotid artery. Carotid intima-media thickness and carotid plaques were simultaneously measured by carotid sonography. Serum concentration of leptin and apolipoprotein were measured using enzyme-linked immuno sorbent assay (ELISA) and nephelometry respectively. Raised CIMT correlated to age of onset of the disease, serum leptin and apoB/apoA-I ratio in psoriasis patients. Taking into account, values that were above the 75 percentile of the three markers (leptin, apoB/apoA-I ratio and CIMT) the odds ratio was 4.26 (2.06-8.80 CI). Leptin and apoB/apoA-I ratio showed significant cumulative association with CIMT. Results of predictive analysis supports measurement of CIMT along with estimation of serum leptin and apoB/apoA-I ratio for prediction of premature atherosclerosis in psoriasis patients.

  18. SDI satellite autonomy using AI and Ada

    NASA Technical Reports Server (NTRS)

    Fiala, Harvey E.

    1990-01-01

    The use of Artificial Intelligence (AI) and the programming language Ada to help a satellite recover from selected failures that could lead to mission failure are described. An unmanned satellite will have a separate AI subsystem running in parallel with the normal satellite subsystems. A satellite monitoring subsystem (SMS), under the control of a blackboard system, will continuously monitor selected satellite subsystems to become alert to any actual or potential problems. In the case of loss of communications with the earth or the home base, the satellite will go into a survival mode to reestablish communications with the earth. The use of an AI subsystem in this manner would have avoided the tragic loss of the two recent Soviet probes that were sent to investigate the planet Mars and its moons. The blackboard system works in conjunction with an SMS and a reconfiguration control subsystem (RCS). It can be shown to be an effective way for one central control subsystem to monitor and coordinate the activities and loads of many interacting subsystems that may or may not contain redundant and/or fault-tolerant elements. The blackboard system will be coded in Ada using tools such as the ABLE development system and the Ada Production system.

  19. Apolipoprotein E genotype in diverse neurodegenerative disorders.

    PubMed

    Schneider, J A; Gearing, M; Robbins, R S; de l'Aune, W; Mirra, S S

    1995-07-01

    While the apolipoprotein E (ApoE) epsilon 4 allele is a recognized risk factor for Alzheimer's disease (AD), an association of epsilon 4 with other neurodegenerative diseases (NDs) has not been extensively explored. We examined 51 cases of neuropathologically confirmed ND. After eliminating 18 cases exhibiting pathology sufficient to warrant an additional diagnosis of AD, three disorders characterized by tau-related cytoskeletal pathology, i.e., Pick's disease, corticobasal degeneration, and progressive supra-nuclear palsy, showed increased epsilon 4 frequencies. Since the number of cases within each category was small, these increased epsilon 4 frequencies were not statistically significant. beta-Amyloid (beta A4) immunoreactive diffuse plaques were observed in many of these cases. While we cannot eliminate the possibility that these patients were destined to develop AD, these changes may merely reflect an independent association of epsilon 4 with amyloid deposition. These preliminary data affirm the need for further study of well-characterized cases to explore the relationship of ApoE to cytoskeletal pathology and ND. PMID:7611717

  20. Apolipoprotein E: from lipid transport to neurobiology.

    PubMed

    Hauser, Paul S; Narayanaswami, Vasanthy; Ryan, Robert O

    2011-01-01

    Apolipoprotein (apo) E has a storied history as a lipid transport protein. The integral association between cholesterol homeostasis and lipoprotein clearance from circulation are intimately related to apoE's function as a ligand for cell-surface receptors of the low-density lipoprotein receptor family. The receptor binding properties of apoE are strongly influenced by isoform specific amino acid differences as well as the lipidation state of the protein. As understanding of apoE as a structural component of circulating plasma lipoproteins has evolved, exciting developments in neurobiology have revitalized interest in apoE. The strong and enduring correlation between the apoE4 isoform and age of onset and increased risk of Alzheimer's disease has catapulted apoE to the forefront of neurobiology. Using genetic tools generated for study of apoE lipoprotein metabolism, transgenic "knock-in" and gene-disrupted mice are now favored models for study of its role in a variety of neurodegenerative diseases. Key structural knowledge of apoE and isoform-specific differences is driving research activity designed to elucidate how a single amino acid change can manifest such profoundly significant pathological consequences. This review describes apoE through a lens of structure-based knowledge that leads to hypotheses that attempt to explain the functions of apoE and isoform-specific effects relating to disease mechanism.

  1. Apolipoproteins in the brain: implications for neurological and psychiatric disorders

    PubMed Central

    Elliott, David A; Weickert, Cyndi Shannon; Garner, Brett

    2011-01-01

    The brain is the most lipid-rich organ in the body and, owing to the impermeable nature of the blood–brain barrier, lipid and lipoprotein metabolism within this organ is distinct from the rest of the body. Apolipoproteins play a well-established role in the transport and metabolism of lipids within the CNS; however, evidence is emerging that they also fulfill a number of functions that extend beyond lipid transport and are critical for healthy brain function. The importance of apolipoproteins in brain physiology is highlighted by genetic studies, where apolipoprotein gene polymorphisms have been identified as risk factors for several neurological diseases. Furthermore, the expression of brain apolipoproteins is significantly altered in several brain disorders. The purpose of this article is to provide an up-to-date assessment of the major apolipoproteins found in the brain (ApoE, ApoJ, ApoD and ApoA-I), covering their proposed roles and the factors influencing their level of expression. Particular emphasis is placed on associations with neurological and psychiatric disorders. PMID:21423873

  2. Quercetin represses apolipoprotein B expression by inhibiting the transcriptional activity of C/EBPβ.

    PubMed

    Shimizu, Makoto; Li, Juan; Inoue, Jun; Sato, Ryuichiro

    2015-01-01

    Quercetin is one of the most abundant polyphenolic flavonoids found in fruits and vegetables and has anti-oxidative and anti-obesity effects. Because the small intestine is a major absorptive organ of dietary nutrients, it is likely that highly concentrated food constituents, including polyphenols, are present in the small intestinal epithelial cells, suggesting that food factors may have a profound effect in this tissue. To identify novel targets of quercetin in the intestinal enterocytes, mRNA profiling using human intestinal epithelial Caco-2 cells was performed. We found that mRNA levels of some apolipoproteins, particularly apolipoprotein B (apoB), are downregulated in the presence of quercetin. On the exposure of Caco-2 cells to quercetin, both mRNA and protein levels of apoB were decreased. Promoter analysis of the human apoB revealed that quercetin response element is localized at the 5'-proximal promoter region, which contains a conserved CCAAT enhancer-binding protein (C/EBP)-response element. We found that quercetin reduces the promoter activity of apoB, driven by the enforced expression of C/EBPβ. Quercetin had no effect on either mRNA or protein levels of C/EBPβ. In contrast, we found that quercetin inhibits the transcriptional activity of C/EBPβ but not its recruitment to the apoB promoter. On the exposure of Caco-2 cells to quercetin 3-O-glucuronide, which is in a cell-impermeable form, no notable change in apoB mRNA was observed, suggesting an intracellular action of quercetin. In vitro interaction experiments using quercetin-conjugated beads revealed that quercetin binds to C/EBPβ. Our results describe a novel regulatory mechanism of transcription of apolipoprotein genes by quercetin in the intestinal enterocytes. PMID:25875015

  3. Structural and Functional Analysis of the ApolipoproteinA-I A164S Variant

    PubMed Central

    Dalla-Riva, Jonathan; Lagerstedt, Jens O.; Petrlova, Jitka

    2015-01-01

    Apolipoprotein A-I (apoA-I) is the main protein involved in the formation of high-density lipoprotein (HDL), it is the principal mediator of the reverse cholesterol transfer (RCT) pathway and provides cardio-protection. In addition to functional wild-type apoA-I, several variants have been shown to associate with hereditary amyloidosis. In this study we have performed biophysical and biochemical analyses of the structure and functional properties of the A164S variant of apoA-I (1:500 in the Danish general population), which is the first known mutation of apoA-I that leads to an increased risk of ischaemic heart disease (IHD), myocardial infarction and mortality without associated low HDL cholesterol levels. Despite the fact that epidemiologically IHD is associated with low plasma levels of HDL, the A164S mutation is linked to normal plasma levels of lipids, HDL and apoA-I, suggesting impaired functionality of this variant. Using biophysical techniques (e.g., circular dichroism spectroscopy and electron microscopy) to determine secondary structure, stability and pro-amyloidogenic property of the lipid free A164S apoA-I variant, our observations suggest similarity in structural properties between apoA-I WT and apoA-I A164S. However, the A164S apoA-I variant exhibits lower binding affinity to lipids but forms similar sized HDL particles to those produced by WT. PMID:26605794

  4. Arsenic exposure accelerates atherogenesis in apolipoprotein E(-/-) mice.

    PubMed

    Simeonova, Petia P; Hulderman, Tracy; Harki, Dan; Luster, Michael I

    2003-11-01

    Epidemiologic studies have shown an association between elevated arsenic levels in drinking water and an increased risk of atherosclerosis and vascular diseases. The studies presented here were performed to evaluate the atherogenic potential of arsenic using a well-established and controlled animal model of human atherosclerosis, mice deficient in apolipoprotein E (ApoE), and in vitro systems including primary human vascular cells. Wild-type and ApoE-deficient mice were exposed to 20 or 100 microg/mL sodium arsenite in drinking water for 24 weeks. As assessed morphometrically, the size of grossly discernible lesions covering the intimal area of aorta were increased significantly in arsenic-treated ApoE-deficient mice compared with nontreated transgenic mice. This effect was not associated with increased levels of serum cholesterol but was accompanied by an accumulation of arsenic in the vessel wall. Introduction of cocoa butter into the diet for 2 weeks resulted in higher serum cholesterol levels and only slight increases in the lesion size in control or arsenic-exposed ApoE-deficient mice. There were no lesions observed in the wild-type C57BL6 mice, resistant to atherosclerosis, whether they received arsenic or control drinking water. In vitro studies, including primary aorta endothelial or smooth muscle cells, were conducted to evaluate whether arsenic induces cellular mechanisms relevant to atherogenesis such as endothelial dysfunction, lipid oxidation, and smooth muscle cell proliferation. Arsenic treatment does not modulate endothelial cell-mediated lipid oxidation or smooth muscle cell proliferation but induced the expression of genes coding inflammatory mediators, including interleukin-8. Induction of endothelial inflammatory activity may play a role in arsenic-related vascular effects.

  5. Apolipoprotein E isoform-specific effects on lipoprotein receptor processing

    PubMed Central

    Bachmeier, Corbin; Shackleton, Ben; Ojo, Joseph; Paris, Daniel; Mullan, Michael; Crawford, Fiona

    2014-01-01

    Recent findings indicate an isoform-specific role for apolipoprotein E (apoE) in the elimination of beta-amyloid (Aβ) from the brain. ApoE is closely associated with various lipoprotein receptors, which contribute to Aβ brain removal via metabolic clearance or transit across the blood-brain barrier (BBB). These receptors are subject to ectodomain shedding at the cell surface, which alters endocytic transport and mitigates Aβ elimination. To further understand the manner in which apoE influences Aβ brain clearance, these studies investigated the effect of apoE on lipoprotein receptor shedding. Consistent with prior reports, we observed an increased shedding of the low density lipoprotein receptor (LDLR) and the LDLR-related protein 1 (LRP1) following Aβ exposure in human brain endothelial cells. When Aβ was co-treated with each apoE isoform, there was a reduction in Aβ-induced shedding with apoE2 and apoE3, while lipoprotein receptor shedding in the presence of apoE4 remained elevated. Likewise, intracranial administration of Aβ to apoE targeted replacement mice (expressing the human apoE isoforms) resulted in an isoform-dependent effect on lipoprotein receptor shedding in the brain (apoE4>apoE3>apoE2). Moreover, these results show a strong inverse correlation with our prior work in apoE transgenic mice in which apoE4 animals showed reduced Aβ clearance across the BBB compared to apoE3 animals. Based on these results, apoE4 appears less efficient than other apoE isoforms in regulating lipoprotein receptor shedding, which may explain the differential effects of these isoforms in removing Aβ from the brain. PMID:25015123

  6. Beef in an Optimal Lean Diet study: effects on lipids, lipoproteins, and apolipoproteins123

    PubMed Central

    Roussell, Michael A; Hill, Alison M; Gaugler, Trent L; West, Sheila G; Vanden Heuvel, John P; Alaupovic, Petar; Gillies, Peter J

    2012-01-01

    Background: A Step I diet with lean beef compared with lean white meat both decrease LDL cholesterol. To our knowledge, no studies have evaluated a low–saturated fatty acid (SFA) (<7% calories) diet that contains lean beef. Objective: We studied the effect on LDL cholesterol of cholesterol-lowering diets with varying amounts of lean beef [ie, Dietary Approaches to Stop Hypertension (DASH): 28 g beef/d; Beef in an Optimal Lean Diet (BOLD): 113 g beef/d; and Beef in an Optimal Lean Diet plus additional protein (BOLD+): 153 g beef/d] compared with that of a healthy American diet (HAD). Design: Thirty-six hypercholesterolemic participants (with LDL-cholesterol concentrations >2.8 mmol/L) were randomly assigned to consume each of the 4 diets (HAD: 33% total fat, 12% SFA, 17% protein, and 20 g beef/d), DASH (27% total fat, 6% SFA, 18% protein, and 28 g beef/d), BOLD (28% total fat, 6% SFA, 19% protein, and 113 g beef/d), and BOLD+ (28% total fat, 6% SFA, 27% protein, and 153 g beef/d) for 5 wk. Results: There was a decrease in total cholesterol (TC) and LDL-cholesterol concentrations (P < 0.05) after consumption of the DASH (−0.49 ± 0.11 and −0.37 ± 0.09 mmol/L, respectively), BOLD (−0.48 ± 0.10 and −0.35 ± 0.9 mmol/L, respectively), and BOLD+ (−0.50 ± 0.10 and −0.345 ± 0.09 mmol/L, respectively) diets compared with after consumption of the HAD (−0.22 ± 0.10 and −0.14 ± 0.10 mmol/L, respectively). Apolipoprotein A-I, C-III, and C-III bound to apolipoprotein A1 particles decreased after BOLD and BOLD+ diets compared with after the HAD, and there was a greater decrease in apolipoprotein B after consumption of the BOLD+ diet than after consumption of the HAD (P < 0.05 for both). LDL cholesterol and TC decreased after consumption of the DASH, BOLD, and BOLD+ diets when the baseline C-reactive protein (CRP) concentration was <1 mg/L; LDL cholesterol and TC decreased when baseline CRP concentration was >1 mg/L with the BOLD and BOLD+ diets

  7. Integrating Vision and AI for Industrial Applications

    NASA Astrophysics Data System (ADS)

    Batchelor, Bruce G.

    1990-03-01

    The article describes an extension to the well-established AI language Prolog. This allows Prolog to operate both an image processing system and a controller for a variety of electro-mechanical devices. The user can define his/her own pull-down menus and provides an interface to a speech synthesis package. The latter enables the user to follow the flow of a program, easily and in a natural way. The application of the software to food inspection is also discussed

  8. Intelligent control: integrating AI and control theory

    SciTech Connect

    De Jong, K.

    1983-01-01

    The increasing complexity of the requirements placed upon computer-controlled systems is forcing a departure from rigid, predetermined control sequences toward more flexible, intelligent control regimes. The basic premise of this research is that such systems can be developed by exploiting the strengths of both standard control theory and recent developments in artificial intelligence. A framework is described for integrating artificial intelligence (AI) techniques with more traditional control theory approaches both at the design stages as well as online control. Its potential is then discussed in the context of several complex navy control problems including automatic tracking systems, autonomous vehicles, and large-scale, flexible space structures. 8 references.

  9. Apolipoprotein A5, a crucial determinant of plasma triglyceridelevels, is highlyresponsive to PPARalpha activators

    SciTech Connect

    Vu-Dac, Ngoc; Gervois, Philippe; Jakel, Heidi; Nowak, Maxine; Bauge, Eric; Dehondt, Helene; Staels, Bart; Pennacchio, Len A.; Fruchart-Najib, Jamila; Fruchart, Jean-Charles

    2003-03-30

    The recently discovered APOA5 gene has been shown in humans and mice to be important in determining plasma triglycerides (TG) levels, a major cardiovascular disease risk factor. APOAV represents the first described apolipoprotein where over-expression lowers triglyceride levels. Since fibrates represent a commonly used therapy for lowering plasma triglycerides in humans, we investigated their ability to modulate APOA5 gene expression and consequently influence plasma TG levels. Human primary hepatocytes treated with Wy 14,643 or fenofibrate displayed a strong induction of APOA5 mRNA. Deletion and mutagenesis analyses of the proximal APOA5 promoter firmly demonstrate the presence of a functional PPAR response element. These findings demonstrate that APOA5 is a highly responsive PPARa target gene and support its role as a major mediator for how fibrates reduce plasma triglycerides in humans.

  10. Mechanism and Physiologic Significance of the Suppression of Cholesterol Esterification in Human Interstitial Fluid

    PubMed Central

    Miller, Norman E.; Olszewski, Waldemar L.; Miller, Irina P.; Nanjee, Mahmud N.

    2016-01-01

    Cholesterol esterification in high density lipoproteins (HDLs) by lecithin:cholesterol acyltransferase (LCAT) promotes unesterified cholesterol (UC) transfer from red cell membranes to plasma in vitro. However, it does not explain the transfer of UC from most peripheral cells to interstitial fluid in vivo, as HDLs in afferent peripheral lymph are enriched in UC. Having already reported that the endogenous cholesterol esterification rate (ECER) in lymph is only 5% of that in plasma, we have now explored the underlying mechanism. In peripheral lymph from 20 healthy men, LCAT concentration, LCAT activity (assayed using an optimized substrate), and LCAT specific activity averaged, respectively, 11.8, 10.3, and 84.9% of plasma values. When recombinant human LCAT was added to lymph, the increments in enzyme activity were similar to those when LCAT was added to plasma. Addition of apolipoprotein AI (apo AI), fatty acid-free albumin, Intralipid, or the d < 1.006 g/ml plasma fraction had no effect on ECER. During incubation of lymph plus plasma, the ECER was similar to that observed with buffer plus plasma. When lymph was added to heat-inactivated plasma, the ECER was 11-fold greater than with lymph plus buffer. Addition of discoidal proteoliposomes of apo AI and phosphatidycholine (PC) to lymph increased ECER 10-fold, while addition of apo AI/PC/UC disks did so by only six-fold. We conclude that the low ECER in lymph is due to a property of the HDLs, seemingly substrate inhibition of LCAT by excess cell-derived UC. This is reversed when lymph enters plasma, consequent upon redistribution of UC from lymph HDLs to plasma lipoproteins. PMID:27471469

  11. Mechanism and Physiologic Significance of the Suppression of Cholesterol Esterification in Human Interstitial Fluid.

    PubMed

    Miller, Norman E; Olszewski, Waldemar L; Miller, Irina P; Nanjee, Mahmud N

    2016-01-01

    Cholesterol esterification in high density lipoproteins (HDLs) by lecithin:cholesterol acyltransferase (LCAT) promotes unesterified cholesterol (UC) transfer from red cell membranes to plasma in vitro. However, it does not explain the transfer of UC from most peripheral cells to interstitial fluid in vivo, as HDLs in afferent peripheral lymph are enriched in UC. Having already reported that the endogenous cholesterol esterification rate (ECER) in lymph is only 5% of that in plasma, we have now explored the underlying mechanism. In peripheral lymph from 20 healthy men, LCAT concentration, LCAT activity (assayed using an optimized substrate), and LCAT specific activity averaged, respectively, 11.8, 10.3, and 84.9% of plasma values. When recombinant human LCAT was added to lymph, the increments in enzyme activity were similar to those when LCAT was added to plasma. Addition of apolipoprotein AI (apo AI), fatty acid-free albumin, Intralipid, or the d < 1.006 g/ml plasma fraction had no effect on ECER. During incubation of lymph plus plasma, the ECER was similar to that observed with buffer plus plasma. When lymph was added to heat-inactivated plasma, the ECER was 11-fold greater than with lymph plus buffer. Addition of discoidal proteoliposomes of apo AI and phosphatidycholine (PC) to lymph increased ECER 10-fold, while addition of apo AI/PC/UC disks did so by only six-fold. We conclude that the low ECER in lymph is due to a property of the HDLs, seemingly substrate inhibition of LCAT by excess cell-derived UC. This is reversed when lymph enters plasma, consequent upon redistribution of UC from lymph HDLs to plasma lipoproteins. PMID:27471469

  12. AI Based Personal Learning Environments: Directions for Long Term Research. AI Memo 384.

    ERIC Educational Resources Information Center

    Goldstein, Ira P.; Miller, Mark L.

    The application of artificial intelligence (AI) techniques to the design of personal learning environments is an enterprise of both theoretical and practical interest. In the short term, the process of developing and testing intelligent tutoring programs serves as a new experimental vehicle for exploring alternative cognitive and pedagogical…

  13. Apolipoprotein E: Risk factor for Alzheimer disease

    SciTech Connect

    Tsai, M.S.; Thibodeau, S.N.; Tangalos, E.G.; Petersen, R.C.; Kokmen, E.; Smith, G.E.; Schaid, D.J.; Ivnik, R.J. )

    1994-04-01

    The apolipoprotein E gene (APOE) has three common alleles (E2, E3, and E4) that determine six genotypes in the general population. In this study, the authors examined 77 patients with late-onset Alzheimer disease (AD), along with an equal number of age- and sex-matched controls, for an association with the APOE-E4 allele. They show that the frequency of this allele among AD patients was significantly higher than that among the control population (.351 vs. .130, P = .000006). The genotype frequencies also differed between the two groups (P = .0002), with the APOE-E4/E3 genotype being the most common in the AD group and the APOE-E3/E3 being the most common in the control group. In the AD group, homozygosity for E4 was found in nine individuals, whereas none was found in the control group. The odds ratio for AD, when associated with one or two E4 alleles, was 4.6 (95% confidence interval [CI] 1.9-12.3), while the odds ratio for AD, when associated with heterozygosity for APOE-E4, was 3.6 (05% CI 1.5-9.8). Finally, the median age at onset among the AD patients decreased from 83 to 78 to 74 years as the number of APOE-E4 alleles increased from 0 to 1 to 2, respectively (test for trend, P = .001). The data, which are in agreement with recent reports, suggest that the APOE-E4 allele is associated with AD and that this allelic variant may be an important risk factor for susceptibility to AD in the general population. 30 refs., 5 tabs.

  14. Impact of apolipoprotein E on Alzheimer's disease.

    PubMed

    Hauser, Paul S; Ryan, Robert O

    2013-10-01

    A key feature of Alzheimer's disease (AD) is deposition of extracellular amyloid plaque comprised chiefly of the amyloid β (Aβ) peptide. Studies of Aβ have shown that it may be catabolized by proteolysis or cleared from brain via members of the low-density lipoprotein receptor family. Alternatively, Aβ can undergo a conformational transition from α-helix to β-sheet, a conformer that displays a propensity to self-associate, oligomerize and form fibrils. Furthermore, β- sheet conformers catalyze conversion of other α-helical Aβ peptides to β-sheet, feeding the oligomer and fibril assembly process. A factor that influences the fate of Aβ in the extracellular space is apolipoprotein (apo) E. Polymorphism at position 112 or 158 in apoE give rise to three major isoforms. One isoform in particular, apoE4 (Arg at 112 and 158), has generated considerable interest since the discovery that it is the major genetic risk factor for development of late onset AD. Despite this striking correlation, the molecular mechanism underlying apoE4's association with AD remains unclear. A tertiary structural feature distinguishing apoE4 from apoE2 and apoE3, termed domain interaction, is postulated to affect the conformation and orientation of its' two independently folded domains. This feature has the potential to influence apoE4's interaction with Aβ, its sensitivity to proteolysis or its lipid accrual and receptor binding activities. Thus, domain interaction may constitute the principal molecular feature of apoE4 that predisposes carriers to late onset AD. By understanding the contribution of apoE4 to AD at the molecular level new therapeutic or prevention strategies will emerge.

  15. The Fat-Fed Apolipoprotein E Knockout Mouse Brachiocephalic Artery in the Study of Atherosclerotic Plaque Rupture

    PubMed Central

    Bond, Andrew R.; Jackson, Christopher L.

    2011-01-01

    Atherosclerosis has been studied in animals for almost a century, yet the events leading up to the rupture of an atherosclerotic plaque (the underlying cause of the majority of fatal thrombosis formation) have only been studied in the past decade, due in part to the development of a mouse model of spontaneous plaque rupture. Apolipoprotein E knockout mice, when fed a high-fat diet, consistently develop lesions in the brachiocephalic artery that rupture at a known time point. It is therefore now possible to observe the development of lesions to elucidate the mechanisms behind the rupture of plaques. Critics argue that the model does not replicate the appearance of human atherosclerotic plaque ruptures. The purpose of this review is to highlight the reasons why we should be looking to the apolipoprotein E knockout mouse to further our understanding of plaque rupture. PMID:21076539

  16. Apolipoprotein E receptors: linking brain development and Alzheimer's disease.

    PubMed

    Herz, J; Beffert, U

    2000-10-01

    Alzheimer's disease is a debilitating neurodegenerative disorder that afflicts an increasing part of our ageing population. An isoform of apolipoprotein E, a protein that mediates the transport of lipids and cholesterol in the circulatory system, predisposes carriers of this allele to the common late-onset form of the disease. How this protein is related to a neurodegenerative disorder is an enigma. Mounting evidence indicates that apolipoprotein E receptors, which are abundantly expressed in most neurons in the central nervous system, also fulfill critical functions during brain development and may profoundly influence the pathogenesis of Alzheimer's disease.

  17. A systems engineering approach to AIS accreditation

    SciTech Connect

    Harris, L.M.; Hunteman, W.J.

    1994-04-01

    The systems engineering model provides the vehicle for communication between the developer and the customer by presenting system facts and demonstrating the system in an organized form. The same model provides implementors with views of the system`s function and capability. The authors contend that the process of obtaining accreditation for a classified Automated Information System (AIS) adheres to the typical systems engineering model. The accreditation process is modeled as a ``roadmap`` with the customer represented by the Designed Accrediting Authority. The ``roadmap`` model reduces the amount of accreditation knowledge required of an AIS developer and maximizes the effectiveness of participation in the accreditation process by making the understanding of accreditation a natural consequence of applying the model. This paper identifies ten ``destinations`` on the ``road`` to accreditation. The significance of each ``destination`` is explained, as are the potential consequences of its exclusion. The ``roadmap,`` which has been applied to a range of information systems throughout the DOE community, establishes a paradigm for the certification and accreditation of classified AISs.

  18. AIS spectra of desert shrub canopies

    NASA Technical Reports Server (NTRS)

    Murray, R.; Isaacson, D. L.; Schrumpf, B. J.; Ripple, W. J.; Lewis, A. J.

    1986-01-01

    Airborne Imaging Spectrometer (AIS) data were collected 30 August 1985 from a desert shrub community in central Oregon. Spectra from artificial targets placed on the test site and from bare soil, big sagebrush (Artemesia tridentata wyomingensis), silver sagebrush (Artemesia cana bolander), and exposed volcanic rocks were studied. Spectral data from grating position 3 (tree mode) were selected from 25 ground positions for analysis by Principal Factor Analysis (PFA). In this grating position, as many as six factors were identified as significant in contributing to spectral structure. Channels 74 through 84 (tree mode) best characterized between-class differences. Other channels were identified as nondiscriminating and as associated with such errors as excessive atmospheric absorption and grating positin changes. The test site was relatively simple with the two species (A. tridentata and A. cana) representing nearly 95% of biomass and with only two mineral backgrounds, a montmorillonitic soil and volcanic rocks. If, as in this study, six factors of spectral structure can be extracted from a single grating position from data acquired over a simple vegetation community, then AIS data must be considered rich in information-gathering potential.

  19. The neurobiology of apolipoproteins and their receptors in the CNS and Alzheimer's disease.

    PubMed

    Beffert, U; Danik, M; Krzywkowski, P; Ramassamy, C; Berrada, F; Poirier, J

    1998-07-01

    The importance of apolipoproteins in the central nervous system became increasingly clear with the association in 1993 of the epsilon4 allele of apolipoprotein E with familial and sporadic late-onset Alzheimer's disease. Apolipoprotein E is a ligand for several receptors, most of which are found to some extent in the brain. This review summarizes the various apolipoproteins and lipoprotein receptors found in the brain. A growing body of evidence now implicates irregular lipoprotein metabolism in several neurodegenerative disorders. We then focus on research linking apolipoprotein E and Alzheimer's disease, from clinical studies to biochemical models, which may explain some of the complex neurobiology of this disorder. PMID:9622609

  20. Tel Aviv-Heidelberg three-generation offspring study: Genetic determinants of apolipoprotein A1 and apolipoprotein B

    SciTech Connect

    Livshits, G.; Graff, E.; Brunner, D.

    1995-07-03

    The contribution of major gene and multifactorial effects on variation of plasma apolipoproteins A1 and B has been tested in a large sample of population-based Israeli pedigrees. Our most parsimonious and best fitting model for both apolipoproteins is consistent with Mendelian transmissibility, with significant contribution of major genes (with 2 alleles recessive and dominant within each locus) and polygenes, but neglects effects of common sib environment as well as related intergeneration differences in polygenic effects. Total genetic effects explain 71 and 58% of phenotypic variance of APO-A1 and APO-B levels. The major genes account for about 44 and 32% of the variance in APO-A1 and APO-B, respectively, and the frequency of the recessive alleles determining the high level of apolipoproteins under the study in the Israeli population is in the vicinity of 40% at each locus. 27 refs, 1 fig., 4 tabs.

  1. Effects of the apolipoprotein E polymorphism on levels of lipids, lipoproteins, and apolipoproteins among Mexican-Americans in Starr County, Texas.

    PubMed

    Hanis, C L; Hewett-Emmett, D; Douglas, T C; Bertin, T K; Schull, W J

    1991-01-01

    Genetic variability has been implicated as a significant contributor to the variation in levels of lipids, lipoproteins, and apolipoproteins (apos) through a variety of direct and indirect investigations. Among the direct investigations, apo E has been shown to be polymorphic and to explain a small but statistically significant proportion of the variability in cholesterol. The apo E polymorphism was typed in 964 randomly selected Mexican-Americans from Starr County, Tex., and its effects determined on levels of cholesterol, triglycerides, total high density lipoprotein (HDL) cholesterol, subfractions (HDL2 and HDL3), alpha- and beta-lipoprotein cholesterol, low density lipoprotein (LDL) cholesterol, and apos A-I, A-II, B, C-II, C-III, and E. Effects are reported for the entire sample and in each of three groups, namely, premenopausal females, postmenopausal women, and males. In the entire sample, significant effects were observed on cholesterol, beta-lipoprotein cholesterol, LDL, apo B, and apo E. There is evidence for significant physiological interaction of the apo E polymorphism effect in females by menopausal status. This is most evident for apo E levels, in which 5.9% of the variability in the entire sample is explained by the apo E polymorphism. In premenopausal females, however, the polymorphism accounts for 27.5% of the variability. In postmenopausal women and males, there is no significant effect. It is shown that the apo E polymorphism can be treated as a two-locus, two-allele system. Doing so identifies substitutions in amino acid position 158 as the mediators of most of the observed effects of this polymorphism. PMID:1998654

  2. Solid lipid nanoparticles as a vehicle for brain-targeted drug delivery: two new strategies of functionalization with apolipoprotein E

    NASA Astrophysics Data System (ADS)

    Rute Neves, Ana; Fontes Queiroz, Joana; Weksler, Babette; Romero, Ignacio A.; Couraud, Pierre-Olivier; Reis, Salette

    2015-12-01

    Nanotechnology can be an important tool to improve the permeability of some drugs for the blood-brain barrier. In this work we created a new system to enter the brain by functionalizing solid lipid nanoparticles with apolipoprotein E, aiming to enhance their binding to low-density lipoprotein receptors on the blood-brain barrier endothelial cells. Solid lipid nanoparticles were successfully functionalized with apolipoprotein E using two distinct strategies that took advantage of the strong interaction between biotin and avidin. Transmission electron microscopy images revealed spherical nanoparticles, and dynamic light scattering gave a Z-average under 200 nm, a polydispersity index below 0.2, and a zeta potential between -10 mV and -15 mV. The functionalization of solid lipid nanoparticles with apolipoprotein E was demonstrated by infrared spectroscopy and fluorimetric assays. In vitro cytotoxic effects were evaluated by MTT and LDH assays in the human cerebral microvascular endothelial cells (hCMEC/D3) cell line, a human blood-brain barrier model, and revealed no toxicity up to 1.5 mg ml-1 over 4 h of incubation. The brain permeability was evaluated in transwell devices with hCMEC/D3 monolayers, and a 1.5-fold increment in barrier transit was verified for functionalized nanoparticles when compared with non-functionalized ones. The results suggested that these novel apolipoprotein E-functionalized nanoparticles resulted in dynamic stable systems capable of being used for an improved and specialized brain delivery of drugs through the blood-brain barrier.

  3. Solid lipid nanoparticles as a vehicle for brain-targeted drug delivery: two new strategies of functionalization with apolipoprotein E.

    PubMed

    Neves, Ana Rute; Queiroz, Joana Fontes; Weksler, Babette; Romero, Ignacio A; Couraud, Pierre-Olivier; Reis, Salette

    2015-12-11

    Nanotechnology can be an important tool to improve the permeability of some drugs for the blood-brain barrier. In this work we created a new system to enter the brain by functionalizing solid lipid nanoparticles with apolipoprotein E, aiming to enhance their binding to low-density lipoprotein receptors on the blood-brain barrier endothelial cells. Solid lipid nanoparticles were successfully functionalized with apolipoprotein E using two distinct strategies that took advantage of the strong interaction between biotin and avidin. Transmission electron microscopy images revealed spherical nanoparticles, and dynamic light scattering gave a Z-average under 200 nm, a polydispersity index below 0.2, and a zeta potential between -10 mV and -15 mV. The functionalization of solid lipid nanoparticles with apolipoprotein E was demonstrated by infrared spectroscopy and fluorimetric assays. In vitro cytotoxic effects were evaluated by MTT and LDH assays in the human cerebral microvascular endothelial cells (hCMEC/D3) cell line, a human blood-brain barrier model, and revealed no toxicity up to 1.5 mg ml(-1) over 4 h of incubation. The brain permeability was evaluated in transwell devices with hCMEC/D3 monolayers, and a 1.5-fold increment in barrier transit was verified for functionalized nanoparticles when compared with non-functionalized ones. The results suggested that these novel apolipoprotein E-functionalized nanoparticles resulted in dynamic stable systems capable of being used for an improved and specialized brain delivery of drugs through the blood-brain barrier.

  4. Cerebral lipid deposition in aged apolipoprotein-E-deficient mice.

    PubMed Central

    Walker, L. C.; Parker, C. A.; Lipinski, W. J.; Callahan, M. J.; Carroll, R. T.; Gandy, S. E.; Smith, J. D.; Jucker, M.; Bisgaier, C. L.

    1997-01-01

    To assess the influence of age and diet on cerebral pathology in mice lacking apolipoprotein E (apoE), four male apoE knockout mice (epsilon -/-), and five male wild-type (epsilon +/+) littermate controls were placed on a high-fat/high-cholesterol diet for 7 weeks beginning at 17 months of age. All four aged knockout mice developed xanthomatous lesions in the brain consisting mostly of crystalline cholesterol clefts, lipid globules, and foam cells. Smaller xanthomas were confined mainly to the choroid plexus and ventral fornix in the roof of the third ventricle, occasionally extending subpially along the choroidal fissure and into the adjacent parenchyma. More advanced xanthomas disrupted adjoining neural tissue in the fornix, hippocampus, and dorsal diencephalon; in one case, over 60% of one telencephalic hemisphere, including nearly the entire neocortex, was obliterated by the lesion. No xanthomas were observed in aged wild-type controls fed the high-fat/high-cholesterol diet. Brains from 42 additional animals, fed only conventional chow, were examined; 3 of 15 aged (15- to 23-month-old) apoE knockout mice developed small choroidal xanthomas. In contrast, no lesions were observed in five young (2- to 4-month-old) apoE knockout mice or in any wild-type controls between the ages of 2 and 23 months. Our findings indicate that disorders of lipid metabolism can induce significant pathological changes in the central nervous system of aged apoE knockout mice, particularly those on a high-fat/high-cholesterol diet. It may be fruitful to seek potential interactions between genetic factors and diet in modulating the risk of Alzheimer's disease and other neurodegenerative disorders in aged humans. Images Figure 1 Figure 2 PMID:9358763

  5. Quantifying the tracking capability of space-based AIS systems

    NASA Astrophysics Data System (ADS)

    Skauen, Andreas Nordmo

    2016-01-01

    The Norwegian Defence Research Establishment (FFI) has operated three Automatic Identification System (AIS) receivers in space. Two are on dedicated nano-satellites, AISSat-1 and AISSat-2. The third, the NORAIS Receiver, was installed on the International Space Station. A general method for calculating the upper bound on the tracking capability of a space-based AIS system has been developed and the results from the algorithm applied to AISSat-1 and the NORAIS Receiver individually. In addition, a constellation of AISSat-1 and AISSat-2 is presented. The tracking capability is defined as the probability of re-detecting ships as they move around the globe and is explained to represent and upper bound on a space-based AIS system performance. AISSat-1 and AISSat-2 operates on the nominal AIS1 and AIS2 channels, while the NORAIS Receiver data used are from operations on the dedicated space AIS channels, AIS3 and AIS4. The improved tracking capability of operations on the space AIS channels is presented.

  6. The implementation of AI technologies in computer wargames

    NASA Astrophysics Data System (ADS)

    Tiller, John A.

    2004-08-01

    Computer wargames involve the most in-depth analysis of general game theory. The enumerated turns of a game like chess are dwarfed by the exponentially larger possibilities of even a simple computer wargame. Implementing challenging AI is computer wargames is an important goal in both the commercial and military environments. In the commercial marketplace, customers demand a challenging AI opponent when they play a computer wargame and are frustrated by a lack of competence on the part of the AI. In the military environment, challenging AI opponents are important for several reasons. A challenging AI opponent will force the military professional to avoid routine or set-piece approaches to situations and cause them to think much deeper about military situations before taking action. A good AI opponent would also include national characteristics of the opponent being simulated, thus providing the military professional with even more of a challenge in planning and approach. Implementing current AI technologies in computer wargames is a technological challenge. The goal is to join the needs of AI in computer wargames with the solutions of current AI technologies. This talk will address several of those issues, possible solutions, and currently unsolved problems.

  7. Increased HDL Size and Enhanced Apo A-I Catabolic Rates Are Associated With Doxorubicin-Induced Proteinuria in New Zealand White Rabbits.

    PubMed

    López-Olmos, Victoria; Carreón-Torres, Elizabeth; Luna-Luna, María; Flores-Castillo, Cristobal; Martínez-Ramírez, Miriam; Bautista-Pérez, Rocío; Franco, Martha; Sandoval-Zárate, Julio; Roldán, Francisco-Javier; Aranda-Fraustro, Alberto; Soria-Castro, Elizabeth; Muñoz-Vega, Mónica; Fragoso, José-Manuel; Vargas-Alarcón, Gilberto; Pérez-Méndez, Oscar

    2016-03-01

    The catabolism and structure of high-density lipoproteins (HDL) may be the determining factor of their atheroprotective properties. To better understand the role of the kidney in HDL catabolism, here we characterized HDL subclasses and the catabolic rates of apo A-I in a rabbit model of proteinuria. Proteinuria was induced by intravenous administration of doxorubicin in New Zealand white rabbits (n = 10). HDL size and HDL subclass lipids were assessed by electrophoresis of the isolated lipoproteins. The catabolic rate of HDL-apo A-I was evaluated by exogenous radiolabelling with iodine-131. Doxorubicin induced significant proteinuria after 4 weeks (4.47 ± 0.55 vs. 0.30 ± 0.02 g/L of protein in urine, P < 0.001) associated with increased uremia, creatininemia, and cardiotoxicity. Large HDL2b augmented significantly during proteinuria, whereas small HDL3b and HDL3c decreased compared to basal conditions. HDL2b, HDL2a, and HDL3a subclasses were enriched with triacylglycerols in proteinuric animals as determined by the triacylglycerol-to-phospholipid ratio; the cholesterol content in HDL subclasses remained unchanged. The fractional catabolic rate (FCR) of [(131)I]-apo A-I in the proteinuric rabbits was faster (FCR = 0.036 h(-1)) compared to control rabbits group (FCR = 0.026 h(-1), P < 0.05). Apo E increased and apo A-I decreased in HDL, whereas PON-1 activity increased in proteinuric rabbits. Proteinuria was associated with an increased number of large HDL2b particles and a decreased number of small HDL3b and 3c. Proteinuria was also connected to an alteration in HDL subclass lipids, apolipoprotein content of HDL, high paraoxonase-1 activity, and a rise in the fractional catabolic rate of the [(131)I]-apo A-I.

  8. Apolipoprotein E and Alzheimer's disease. A role in amyloid catabolism.

    PubMed

    Poirier, J

    2000-01-01

    It has been shown over the past few years that apolipoprotein E (apoE) plays a central role in the brain response to injury and neurodegeneration in mammalian species. The coordinated expression of apoE and its different receptors, the so-called LDL receptor family, appears to regulate the transport of cholesterol and phospholipids during the early and middle phases of the reinnervation in the adult mammalian brain. As neurons undergo dendritic remodelling and synaptogenesis using cholesterol internalization through the apoE/LDL receptor pathway, they progressively shut down 3,3-hydroxymethylglutaryl-Coenzyme A (HMG CoA) reductase activity, the rate-limiting enzyme in the synthesis of cholesterol. These results suggest that cholesterol delivery and synthesis in the brain are tightly regulated through an apoE-dependent mechanism. The discovery that the apolipoprotein e4 allele is strongly linked to both sporadic and familial late-onset Alzheimer's disease (AD) has raised the possibility that a dysfunction of lipid transport could explain the poor compensatory synaptogenesis reported by several independent research groups in the brain of AD subjects. Recently, it has been shown that alterations of cholesterol homeostasis in the brain by exogenous administration of dietary cholesterol, or through inhibition of cholesterol synthesis, markedly affect beta amyloid production (1-40 and 1-42) and deposition and significantly impair amyloid precursor protein (APP) metabolism. In vivo, it has been shown that breeding of APP-overexpressing mice with apoE knockout mice completely abolishes amyloid plaque deposition in the brain of hybrid animals, without affecting beta amyloid steady state levels. Conversely, introduction of the human apoE3 and apoE4 genes in APP-overexpressing mice drastically reduced beta amyloid deposition in the brain of hybrid mice, confirming the proposed biological role of apoE in the clearance of extracellular beta amyloid. These results indicate that

  9. AI tools in computer based problem solving

    NASA Technical Reports Server (NTRS)

    Beane, Arthur J.

    1988-01-01

    The use of computers to solve value oriented, deterministic, algorithmic problems, has evolved a structured life cycle model of the software process. The symbolic processing techniques used, primarily in research, for solving nondeterministic problems, and those for which an algorithmic solution is unknown, have evolved a different model, much less structured. Traditionally, the two approaches have been used completely independently. With the advent of low cost, high performance 32 bit workstations executing identical software with large minicomputers and mainframes, it became possible to begin to merge both models into a single extended model of computer problem solving. The implementation of such an extended model on a VAX family of micro/mini/mainframe systems is described. Examples in both development and deployment of applications involving a blending of AI and traditional techniques are given.

  10. Application of AIS Technology to Forest Mapping

    NASA Technical Reports Server (NTRS)

    Yool, S. R.; Star, J. L.

    1985-01-01

    Concerns about environmental effects of large scale deforestation have prompted efforts to map forests over large areas using various remote sensing data and image processing techniques. Basic research on the spectral characteristics of forest vegetation are required to form a basis for development of new techniques, and for image interpretation. Examination of LANDSAT data and image processing algorithms over a portion of boreal forest have demonstrated the complexity of relations between the various expressions of forest canopies, environmental variability, and the relative capacities of different image processing algorithms to achieve high classification accuracies under these conditions. Airborne Imaging Spectrometer (AIS) data may in part provide the means to interpret the responses of standard data and techniques to the vegetation based on its relatively high spectral resolution.

  11. Walnut-enriched diet increases the association of LDL from hypercholesterolemic men with human HepG2 cells.

    PubMed

    Muñoz, S; Merlos, M; Zambón, D; Rodríguez, C; Sabaté, J; Ros, E; Laguna, J C

    2001-12-01

    In a randomized, cross-over feeding trial involving 10 men with polygenic hypercholesterolemia, a control, Mediterranean-type cholesterol-lowering diet, and a diet of similar composition in which walnuts replaced approximately 35% of energy from unsaturated fat, were given for 6 weeks each. Compared with the control diet, the walnut diet reduced serum total and LDL cholesterol by 4.2% (P = 0.176), and 6.0% (P = 0.087), respectively. No changes were observed in HDL cholesterol, triglycerides, and apolipoprotein A-I levels or in the relative proportion of protein, triglycerides, phospholipids, and cholesteryl esters in LDL particles. The apolipoprotein B level declined in parallel with LDL cholesterol (6.0% reduction). Whole LDL, particularly the triglyceride fraction, was enriched in polyunsaturated fatty acids from walnuts (linoleic and alpha-linolenic acids). In comparison with LDL obtained during the control diet, LDL obtained during the walnut diet showed a 50% increase in association rates to the LDL receptor in human hepatoma HepG2 cells. LDL uptake by HepG2 cells was correlated with alpha-linolenic acid content of the triglyceride plus cholesteryl ester fractions of LDL particles (r(2) = 0.42, P < 0.05). Changes in the quantity and quality of LDL lipid fatty acids after a walnut-enriched diet facilitate receptor-mediated LDL clearance and may contribute to the cholesterol-lowering effect of walnut consumption.

  12. AI And Early Vision - Part II

    NASA Astrophysics Data System (ADS)

    Julesz, Bela

    1989-08-01

    A quarter of a century ago I introduced two paradigms into psychology which in the intervening years have had a direct impact on the psychobiology of early vision and an indirect one on artificial intelligence (AI or machine vision). The first, the computer-generated random-dot stereogram (RDS) paradigm (Julesz, 1960) at its very inception posed a strategic question both for AI and neurophysiology. The finding that stereoscopic depth perception (stereopsis) is possible without the many enigmatic cues of monocular form recognition - as assumed previously - demonstrated that stereopsis with its basic problem of finding matches between corresponding random aggregates of dots in the left and right visual fields became ripe for modeling. Indeed, the binocular matching problem of stereopsis opened up an entire field of study, eventually leading to the computational models of David Marr (1982) and his coworkers. The fusion of RDS had an even greater impact on neurophysiologists - including Hubel and Wiesel (1962) - who realized that stereopsis must occur at an early stage, and can be studied easier than form perception. This insight recently culminated in the studies by Gian Poggio (1984) who found binocular-disparity - tuned neurons in the input stage to the visual cortex (layer IVB in V1) in the monkey that were selectively triggered by dynamic RDS. Thus the first paradigm led to a strategic insight: that with stereoscopic vision there is no camouflage, and as such was advantageous for our primate ancestors to evolve the cortical machinery of stereoscopic vision to capture camouflaged prey (insects) at a standstill. Amazingly, although stereopsis evolved relatively late in primates, it captured the very input stages of the visual cortex. (For a detailed review, see Julesz, 1986a)

  13. Intralipid Decreases Apolipoprotein M Levels and Insulin Sensitivity in Rats

    PubMed Central

    Zheng, Lu; Feng, Yuehua; Shi, Yuanping; Zhang, Jun; Mu, Qinfeng; Qin, Li; Berggren-Söderlund, Maria; Nilsson-Ehle, Peter; Zhang, Xiaoying; Luo, Guanghua; Xu, Ning

    2014-01-01

    Background Apolipoprotein M (ApoM) is a constituent of high-density lipoproteins (HDL). It plays a crucial role in HDL-mediated reverse cholesterol transport. Insulin resistance is associated with decreased ApoM levels. Aims To assess the effects of increased free fatty acids (FFAs) levels after short-term Intralipid infusion on insulin sensitivity and hepatic ApoM gene expression. Methods Adult male Sprague-Dawley (SD) rats infused with 20% Intralipid solution for 6 h. Glucose infusion rates (GIR) were determined by hyperinsulinemic-euglycemic clamp during Intralipid infusion and plasma FFA levels were measured by colorimetry. Rats were sacrificed after Intralipid treatment and livers were sampled. Human embryonic kidney 293T cells were transfected with a lentivirus mediated human apoM overexpression system. Goto-Kakizaki (GK) rats were injected with the lentiviral vector and insulin tolerance was assessed. Gene expression was assessed by real-time RT-PCR and PCR array. Results Intralipid increased FFAs by 17.6 folds and GIR was decreased by 27.1% compared to the control group. ApoM gene expression was decreased by 40.4% after Intralipid infusion. PPARβ/δ expression was not changed by Intralipid. Whereas the mRNA levels of Acaca, Acox1, Akt1, V-raf murine sarcoma 3611 viral oncogene homolog, G6pc, Irs2, Ldlr, Map2k1, pyruvate kinase and RBC were significantly increased in rat liver after Intralipid infusion. The Mitogen-activated protein kinase 8 (MAPK8) was significantly down-regulated in 293T cells overexpressing ApoM. Overexpression of human ApoM in GK rats could enhance the glucose-lowering effect of exogenous insulin. Conclusion These results suggest that Intralipid could decrease hepatic ApoM levels. ApoM overexpression may have a potential role in improving insulin resistance in vivo and modulating apoM expression might be a future therapeutic strategy against insulin resistance in type 2 diabetes. PMID:25144649

  14. Immunoquantification of total apolipoprotein B in serum by nephelometry: influence of lipase treatment and detergents.

    PubMed

    DaCol, P; Kostner, G M

    1983-06-01

    The immunoquantification of total apolipoprotein B in human serum has been evaluated by rate and equilibrium nephelometry. The presence of triglyceride-rich lipoproteins spoiled all immunochemical assays and yielded too-high values for apolipoprotein B. The use of detergents improved the results substantially, but results were inaccurate at high triglyceride concentrations. Of many detergents investigated, only Thesit, Kryo Ebo, and Apovax were useful, decreasing the light-scatter signals almost linearly with increasing detergent concentrations. The regression lines, however, were not parallel among the different apo B-containing lipoproteins. Incubating sera or apo B-containing lipoproteins with bovine milk lipoprotein lipase or bacterial triacylglycerol lipase, at concentrations of 100 kU/L, hydrolyzed all of the triglycerides and most of the phosphatidylcholine within 18 h at 37 degrees C Lipase-pretreatment of samples gave optimal correlation between apo B values as determined by nephelometry with those obtained gravimetrically. We also assessed the influence of sample storage, freezing, and thawing on the nephelometric apo B assays.

  15. Suppressive effects of cacao polyphenols on the development of atherosclerosis in apolipoprotein E-deficient mice.

    PubMed

    Natsume, Midori; Baba, Seigo

    2014-01-01

    Previous studies in humans have shown that the cacao polyphenols, (-)-epicatechin and its oligomers, prevent in vitro and ex vivo low-density lipoprotein oxidation mediated by free radical generators and metal ions and also reduce plasma LDL-cholesterol levels. The aim of this study was to examine the effects of cacao polyphenols on the development of atherosclerosis in apolipoprotein E-deficient (-/-) mice. Mice aged 8 weeks (n = 90) were randomized into three groups, and fed either normal mouse chow (controls) or chow supplemented with 0.25 or 0.40 % cacao polyphenols for 16 weeks. The mean plaque area in cross-sections of the brachiocephalic trunk was measured and found to be lower in the 0.25 % cacao polyphenol group than in the control group (p < 0.05). Pathological observations showed that accumulation of cholesterol crystals in the plaque area was greater in the control group compared with the 0.40 % cacao polyphenol group (p < 0.05). Immunochemical staining in the 0.25 and 0.40 % groups showed that expression of the cell adhesion molecules (VCAM-1 and ICAM-1) and production of oxidative stress markers (4-hydroxynonenal, hexanoyl-lysine, and dityrosine) were reduced in cross-sections of the brachiocephalic trunk. These results suggest that cacao polyphenols inhibit the development of atherosclerosis in apolipoprotein E-deficient (-/-) mice by reducing oxidative stress and inflammatory responses. PMID:24374929

  16. Suppressive effects of cacao polyphenols on the development of atherosclerosis in apolipoprotein E-deficient mice.

    PubMed

    Natsume, Midori; Baba, Seigo

    2014-01-01

    Previous studies in humans have shown that the cacao polyphenols, (-)-epicatechin and its oligomers, prevent in vitro and ex vivo low-density lipoprotein oxidation mediated by free radical generators and metal ions and also reduce plasma LDL-cholesterol levels. The aim of this study was to examine the effects of cacao polyphenols on the development of atherosclerosis in apolipoprotein E-deficient (-/-) mice. Mice aged 8 weeks (n = 90) were randomized into three groups, and fed either normal mouse chow (controls) or chow supplemented with 0.25 or 0.40 % cacao polyphenols for 16 weeks. The mean plaque area in cross-sections of the brachiocephalic trunk was measured and found to be lower in the 0.25 % cacao polyphenol group than in the control group (p < 0.05). Pathological observations showed that accumulation of cholesterol crystals in the plaque area was greater in the control group compared with the 0.40 % cacao polyphenol group (p < 0.05). Immunochemical staining in the 0.25 and 0.40 % groups showed that expression of the cell adhesion molecules (VCAM-1 and ICAM-1) and production of oxidative stress markers (4-hydroxynonenal, hexanoyl-lysine, and dityrosine) were reduced in cross-sections of the brachiocephalic trunk. These results suggest that cacao polyphenols inhibit the development of atherosclerosis in apolipoprotein E-deficient (-/-) mice by reducing oxidative stress and inflammatory responses.

  17. Distinct apolipoprotein E isoform preference for inhibition of smooth muscle cell migration and proliferation.

    PubMed

    Zeleny, Michelle; Swertfeger, Debi K; Weisgraber, Karl H; Hui, David Y

    2002-10-01

    The current study compared the effectiveness of the various human apolipoprotein E (apoE) isoforms in inhibiting platelet-derived growth factor- (PDGF-) stimulated smooth muscle cell proliferation and migration. The incubation of primary mouse aortic smooth muscle cells with apoE3 resulted in dose-dependent inhibition of smooth muscle cells stimulated by 10 ng/mL PDGF. Greater than 50% inhibition of smooth muscle cell proliferation was observed at 15 microg/mL of human apoE3. Human apoE2 was less effective, requiring a higher concentration to achieve inhibition comparable to that of apoE3. Human apoE4 was the least effective of the apoE isoforms with no significant inhibition of cell proliferation observed at concentrations up to 15 microg/mL. Interestingly, apoE inhibition of PDGF-directed smooth muscle cell migration did not show preference for any apoE isoforms. Human apoE2, apoE3, and apoE4 were equally effective in inhibiting smooth muscle cell migration toward PDGF. These results are consistent with previous data showing that apoE inhibition of smooth muscle cell proliferation is mediated through its binding to heparan sulfate proteoglycans, whereas its inhibition of cell migration is mediated via binding to the low-density lipoprotein receptor related protein. The low efficiency of apoE4 to inhibit smooth muscle cell proliferation also suggested another mechanism to explain the association between the apolipoprotein epsilon4 allele with increased risk of coronary artery disease. PMID:12269825

  18. Apolipoprotein C-I is an APOE genotype-dependent suppressor of glial activation

    PubMed Central

    2012-01-01

    Background Inheritance of the human ϵ4 allele of the apolipoprotein (apo) E gene (APOE) significantly increases the risk of developing Alzheimer’s disease (AD), in addition to adversely influencing clinical outcomes of other neurologic diseases. While apoE isoforms differentially interact with amyloid β (Aβ), a pleiotropic neurotoxin key to AD etiology, more recent work has focused on immune regulation in AD pathogenesis and on the mechanisms of innate immunomodulatory effects associated with inheritance of different APOE alleles. APOE genotype modulates expression of proximal genes including APOC1, which encodes a small apolipoprotein that is associated with Aβ plaques. Here we tested the hypothesis that APOE-genotype dependent innate immunomodulation may be mediated in part by apoC-I. Methods ApoC-I concentration in cerebrospinal fluid from control subjects of differing APOE genotypes was quantified by ELISA. Real-time PCR and ELISA were used to analyze apoC-I mRNA and protein expression, respectively, in liver, serum, cerebral cortex, and cultured primary astrocytes derived from mice with targeted replacement of murine APOE for human APOE ϵ3 or ϵ4. ApoC-I direct modulation of innate immune activity was investigated in cultured murine primary microglia and astrocytes, as well as human differentiated macrophages, using specific toll-like receptor agonists LPS and PIC as well as Aβ. Results ApoC-I levels varied with APOE genotype in humans and in APOE targeted replacement mice, with ϵ4 carriers showing significantly less apoC-I in both species. ApoC-I potently reduced pro-inflammatory cytokine secretion from primary murine microglia and astrocytes, and human macrophages, stimulated with LPS, PIC, or Aβ. Conclusions ApoC-I is immunosuppressive. Our results illuminate a novel potential mechanism for APOE genotype risk for AD; one in which patients with an ϵ4 allele have decreased expression of apoC-I resulting in increased innate immune activity. PMID

  19. Pedagogy and the PC: Trends in the AIS Curriculum

    ERIC Educational Resources Information Center

    Badua, Frank

    2008-01-01

    The author investigated the array of course topics in accounting information systems (AIS), as course syllabi embody. The author (a) used exploratory data analysis to determine the topics that AIS courses most frequently offered and (b) used descriptive statistics and econometric analysis to trace the diversity of course topics through time,…

  20. An Immune Agent for Web-Based AI Course

    ERIC Educational Resources Information Center

    Gong, Tao; Cai, Zixing

    2006-01-01

    To overcome weakness and faults of a web-based e-learning course such as Artificial Intelligence (AI), an immune agent was proposed, simulating a natural immune mechanism against a virus. The immune agent was built on the multi-dimension education agent model and immune algorithm. The web-based AI course was comprised of many files, such as HTML…

  1. The Social Stratification of /aI/ in Tuscaloosa, Alabama.

    ERIC Educational Resources Information Center

    Crane, L. Ben

    This study is a sociolinguistic analysis of the variant pronunciation of /aI/, a selected phonological variable, by white informants in Tuscaloosa, Alabama. Through a purposive sampling procedure, 56 informants were interviewed to determine their pronunciation of /aI/. Informants were ranked according to education, income, and occupation to…

  2. Integrating the Wall Street Journal into AIS Courses

    ERIC Educational Resources Information Center

    Kohlmeyer, James M., III

    2008-01-01

    While it is important for accounting information systems (AIS) students to understand computer technology, internal controls and business processes, such knowledge is of little use without reference to appropriate contexts. Integrating Wall Street Journal (WSJ) readings and discussions into AIS classes can enrich learning by stimulating…

  3. Ada in AI or AI in Ada. On developing a rationale for integration

    NASA Technical Reports Server (NTRS)

    Collard, Philippe E.; Goforth, Andre

    1988-01-01

    The use of Ada as an Artificial Intelligence (AI) language is gaining interest in the NASA Community, i.e., by parties who have a need to deploy Knowledge Based-Systems (KBS) compatible with the use of Ada as the software standard for the Space Station. A fair number of KBS and pseudo-KBS implementations in Ada exist today. Currently, no widely used guidelines exist to compare and evaluate these with one another. The lack of guidelines illustrates a fundamental problem inherent in trying to compare and evaluate implementations of any sort in languages that are procedural or imperative in style, such as Ada, with those in languages that are functional in style, such as Lisp. Discussed are the strengths and weakness of using Ada as an AI language and a preliminary analysis provided of factors needed for the development of criteria for the integration of these two families of languages and the environments in which they are implemented. The intent for developing such criteria is to have a logical rationale that may be used to guide the development of Ada tools and methodology to support KBS requirements, and to identify those AI technology components that may most readily and effectively be deployed in Ada.

  4. Neuropathology and apolipoprotein E profile of aged chimpanzees: implications for Alzheimer disease.

    PubMed Central

    Gearing, M; Rebeck, G W; Hyman, B T; Tigges, J; Mirra, S S

    1994-01-01

    Neuropathological findings in three aged chimpanzees were compared with those in rhesus monkeys and individuals with Alzheimer disease. Senile plaques and blood vessels were immunoreactive for amyloid beta-protein and apolipoprotein E (apoE) in the nonhuman primates, recapitulating findings in human aging and Alzheimer disease. Neurofibrillary tangles, another hallmark of Alzheimer disease, were absent. PCR/restriction-enzyme analysis in chimpanzees revealed an APOE profile similar to the human APOE type 4 allele associated with an increased risk of Alzheimer disease. These findings militate against the hypothesis that the absence of APOE type 3 allele predisposes to neurofibrillary tangle formation and support the value of aged primates for exploring mechanisms of amyloid processing and the role of apoE. Images PMID:7937774

  5. Melissa officinalis essential oil reduces plasma triglycerides in human apolipoprotein E2 transgenic mice by inhibiting sterol regulatory element-binding protein-1c-dependent fatty acid synthesis.

    PubMed

    Jun, Hee-Jin; Lee, Ji Hae; Jia, Yaoyao; Hoang, Minh-Hien; Byun, Hanna; Kim, Kyoung Heon; Lee, Sung-Joon

    2012-03-01

    We investigated the hypolipidemic effects of Melissa officinalis essential oil (MOEO) in human APOE2 transgenic mice and lipid-loaded HepG2 cells. Plasma TG concentrations were significantly less in APOE2 mice orally administered MOEO (12.5 μg/d) for 2 wk than in the vehicle-treated group. Cellular TG and cholesterol concentrations were also significantly decreased in a dose- (400 and 800 mg/L) and time- (12 and 24 h) dependent manner in HepG2 cells stimulated with MOEO compared with controls. Mouse hepatic transcriptome analysis suggested MOEO feeding altered several lipid metabolic pathways, including bile acid and cholesterol synthesis and fatty acid metabolism. In HepG2 cells, the rate of fatty acid oxidation, as assessed using [1-(14)C]palmitate, was unaltered; however, the rate of fatty acid synthesis quantified with [1-(14)C]acetate was significantly reduced by treatment with 400 and 800 mg/L MOEO compared with untreated controls. This reduction was due to the decreased expression of SREBP-1c and its responsive genes in fatty acid synthesis, including FAS, SCD1, and ACC1. Subsequent chromatin immunoprecipitation analysis further demonstrated that the binding of p300/CBP-associated factor, a coactivator of SREBP-1c, and histone H3 lysine 14 acetylation at the FAS, SCD1, and ACC1 promoters were significantly reduced in the livers of APOE2 mice and HepG2 cells treated with MOEO compared with their controls. Additionally, MOEO stimulation in HepG2 cells induced bile acid synthesis and reduced the nuclear form of SREBP-2, a key transcription factor in hepatic cholesterol synthesis. These findings suggest that the intake of phytochemicals with pleasant scent could have beneficial metabolic effects.

  6. Turkish Heart Study: lipids, lipoproteins, and apolipoproteins.

    PubMed

    Mahley, R W; Palaoğlu, K E; Atak, Z; Dawson-Pepin, J; Langlois, A M; Cheung, V; Onat, H; Fulks, P; Mahley, L L; Vakar, F

    1995-04-01

    We examined the plasma lipids, lipoproteins, and selected apolipoproteins in approximately 9,000 men and women from six different regions of Turkey with markedly different diets, ranging from an Aegean coast diet high in olive oil (plasma cholesteryl ester fatty acids enriched in monounsaturated fatty acids) to an inland Anatolian diet high in meat and dairy products (plasma cholesteryl esters enriched in saturated fatty acids). The rural population consuming an olive oil-rich diet had the lowest plasma cholesterol levels (men, 149 mg/dl; women, 150 mg/dl). The urban populations of Istanbul and Adana had higher plasma cholesterol levels (men, 202 and 184 mg/dl, respectively; women, 181 and 190 mg/dl, respectively). Affluent men had the highest cholesterol levels (207 mg/dl). The low density lipoprotein (LDL) cholesterol levels tended to parallel the total cholesterol levels (highest for Istanbul men at 136 mg/dl and lowest for Aegean coast men and women at approximately 100 mg/dl). Strikingly, the Turkish people were found to have very low levels of high density lipoprotein (HDL) cholesterol (HDL-C) (mean values for all six regions: men, 34-38 mg/dl; women, 37-45 mg/dl) and total cholesterol/HDL-C ratios that were high (mean values for all six regions: men, 4.5-5.5; women, 3.9-5.0). The low HDL-C levels appear to be caused, at least in part, by a genetic factor. Triglyceride levels also tended to be high in Turkish men (approximately 120-150 mg/dl) and women (approximately 90-110 mg/dl). Thus, even though the total plasma cholesterol levels are not excessively elevated in comparison to those in other populations, the presence of low HDL-C or low HDL-C coupled with mildly elevated triglyceride levels may represent a significant risk factor for heart disease in the Turkish population. Affluence and higher education were associated with higher cholesterol levels. Lack of physical activity, smoking, and alcohol consumption also tended to be associated with a

  7. A Systematic Investigation of Structure/Function Requirements for the Apolipoprotein A-I/Lecithin Cholesterol Acyltransferase Interaction Loop of High-density Lipoprotein.

    PubMed

    Gu, Xiaodong; Wu, Zhiping; Huang, Ying; Wagner, Matthew A; Baleanu-Gogonea, Camelia; Mehl, Ryan A; Buffa, Jennifer A; DiDonato, Anthony J; Hazen, Leah B; Fox, Paul L; Gogonea, Valentin; Parks, John S; DiDonato, Joseph A; Hazen, Stanley L

    2016-03-18

    The interaction of lecithin-cholesterol acyltransferase (LCAT) with apolipoprotein A-I (apoA-I) plays a critical role in high-density lipoprotein (HDL) maturation. We previously identified a highly solvent-exposed apoA-I loop domain (Leu(159)-Leu(170)) in nascent HDL, the so-called "solar flare" (SF) region, and proposed that it serves as an LCAT docking site (Wu, Z., Wagner, M. A., Zheng, L., Parks, J. S., Shy, J. M., 3rd, Smith, J. D., Gogonea, V., and Hazen, S. L. (2007) Nat. Struct. Mol. Biol. 14, 861-868). The stability and role of the SF domain of apoA-I in supporting HDL binding and activation of LCAT are debated. Here we show by site-directed mutagenesis that multiple residues within the SF region (Pro(165), Tyr(166), Ser(167), and Asp(168)) of apoA-I are critical for both LCAT binding to HDL and LCAT catalytic efficiency. The critical role for possible hydrogen bond interaction at apoA-I Tyr(166) was further supported using reconstituted HDL generated from apoA-I mutants (Tyr(166) → Glu or Asn), which showed preservation in both LCAT binding affinity and catalytic efficiency. Moreover, the in vivo functional significance of NO2-Tyr(166)-apoA-I, a specific post-translational modification on apoA-I that is abundant within human atherosclerotic plaque, was further investigated by using the recombinant protein generated from E. coli containing a mutated orthogonal tRNA synthetase/tRNACUA pair enabling site-specific insertion of the unnatural amino acid into apoA-I. NO2-Tyr(166)-apoA-I, after subcutaneous injection into hLCAT(Tg/Tg), apoA-I(-/-) mice, showed impaired LCAT activation in vivo, with significant reduction in HDL cholesteryl ester formation. The present results thus identify multiple structural features within the solvent-exposed SF region of apoA-I of nascent HDL essential for optimal LCAT binding and catalytic efficiency.

  8. A Systematic Investigation of Structure/Function Requirements for the Apolipoprotein A-I/Lecithin Cholesterol Acyltransferase Interaction Loop of High-density Lipoprotein.

    PubMed

    Gu, Xiaodong; Wu, Zhiping; Huang, Ying; Wagner, Matthew A; Baleanu-Gogonea, Camelia; Mehl, Ryan A; Buffa, Jennifer A; DiDonato, Anthony J; Hazen, Leah B; Fox, Paul L; Gogonea, Valentin; Parks, John S; DiDonato, Joseph A; Hazen, Stanley L

    2016-03-18

    The interaction of lecithin-cholesterol acyltransferase (LCAT) with apolipoprotein A-I (apoA-I) plays a critical role in high-density lipoprotein (HDL) maturation. We previously identified a highly solvent-exposed apoA-I loop domain (Leu(159)-Leu(170)) in nascent HDL, the so-called "solar flare" (SF) region, and proposed that it serves as an LCAT docking site (Wu, Z., Wagner, M. A., Zheng, L., Parks, J. S., Shy, J. M., 3rd, Smith, J. D., Gogonea, V., and Hazen, S. L. (2007) Nat. Struct. Mol. Biol. 14, 861-868). The stability and role of the SF domain of apoA-I in supporting HDL binding and activation of LCAT are debated. Here we show by site-directed mutagenesis that multiple residues within the SF region (Pro(165), Tyr(166), Ser(167), and Asp(168)) of apoA-I are critical for both LCAT binding to HDL and LCAT catalytic efficiency. The critical role for possible hydrogen bond interaction at apoA-I Tyr(166) was further supported using reconstituted HDL generated from apoA-I mutants (Tyr(166) → Glu or Asn), which showed preservation in both LCAT binding affinity and catalytic efficiency. Moreover, the in vivo functional significance of NO2-Tyr(166)-apoA-I, a specific post-translational modification on apoA-I that is abundant within human atherosclerotic plaque, was further investigated by using the recombinant protein generated from E. coli containing a mutated orthogonal tRNA synthetase/tRNACUA pair enabling site-specific insertion of the unnatural amino acid into apoA-I. NO2-Tyr(166)-apoA-I, after subcutaneous injection into hLCAT(Tg/Tg), apoA-I(-/-) mice, showed impaired LCAT activation in vivo, with significant reduction in HDL cholesteryl ester formation. The present results thus identify multiple structural features within the solvent-exposed SF region of apoA-I of nascent HDL essential for optimal LCAT binding and catalytic efficiency. PMID:26797122

  9. Apolipoprotein E4 effects in Alzheimer's disease are mediated by synaptotoxic oligomeric amyloid-β.

    PubMed

    Koffie, Robert M; Hashimoto, Tadafumi; Tai, Hwan-Ching; Kay, Kevin R; Serrano-Pozo, Alberto; Joyner, Daniel; Hou, Steven; Kopeikina, Katherine J; Frosch, Matthew P; Lee, Virginia M; Holtzman, David M; Hyman, Bradley T; Spires-Jones, Tara L

    2012-07-01

    The apolipoprotein E ε4 gene is the most important genetic risk factor for sporadic Alzheimer's disease, but the link between this gene and neurodegeneration remains unclear. Using array tomography, we analysed >50000 synapses in brains of 11 patients with Alzheimer's disease and five non-demented control subjects and found that synapse loss around senile plaques in Alzheimer's disease correlates with the burden of oligomeric amyloid-β in the neuropil and that this synaptotoxic oligomerized peptide is present at a subset of synapses. Further analysis reveals apolipoprotein E ε4 patients with Alzheimer's disease have significantly higher oligomeric amyloid-β burden and exacerbated synapse loss around plaques compared with apolipoprotein E ε3 patients. Apolipoprotein E4 protein colocalizes with oligomeric amyloid-β and enhances synaptic localization of oligomeric amyloid-β by >5-fold. Biochemical characterization shows that the amyloid-β enriched at synapses by apolipoprotein E4 includes sodium dodecyl sulphate-stable dimers and trimers. In mouse primary neuronal culture, lipidated apolipoprotein E4 enhances oligomeric amyloid-β association with synapses via a mechanism involving apolipoprotein E receptors. Together, these data suggest that apolipoprotein E4 is a co-factor that enhances the toxicity of oligomeric amyloid-β both by increasing its levels and directing it to synapses, providing a link between apolipoprotein E ε4 genotype and synapse loss, a major correlate of cognitive decline in Alzheimer's disease.

  10. Conformational flexibility in the apolipoprotein E amino-terminal domain structure determined from three new crystal forms: implications for lipid binding.

    PubMed Central

    Segelke, B. W.; Forstner, M.; Knapp, M.; Trakhanov, S. D.; Parkin, S.; Newhouse, Y. M.; Bellamy, H. D.; Weisgraber, K. H.; Rupp, B.

    2000-01-01

    An amino-terminal fragment of human apolipoprotein E3 (residues 1-165) has been expressed and crystallized in three different crystal forms under similar crystallization conditions. One crystal form has nearly identical cell dimensions to the previously reported orthorhombic (P2(1)2(1)2(1)) crystal form of the amino-terminal 22 kDa fragment of apolipoprotein E (residues 1-191). A second orthorhombic crystal form (P2(1)2(1)2(1) with cell dimensions differing from the first form) and a trigonal (P3(1)21) crystal form were also characterized. The structures of the first orthorhombic and the trigonal form were determined by seleno-methionine multiwavelength anomalous dispersion, and the structure of the second orthorhombic form was determined by molecular replacement using the structure from the trigonal form as a search model. A combination of modern experimental and computational techniques provided high-quality electron-density maps, which revealed new features of the apolipoprotein E structure, including an unambiguously traced loop connecting helices 2 and 3 in the four-helix bundle and a number of multiconformation side chains. The three crystal forms contain a common intermolecular, antiparallel packing arrangement. The electrostatic complimentarity observed in this antiparallel packing resembles the interaction of apolipoprotein E with the monoclonal antibody 2E8 and the low density lipoprotein receptor. Superposition of the model structures from all three crystal forms reveals flexibility and pronounced kinks in helices near one end of the four-helix bundle. This mobility at one end of the molecule provides new insights into the structural changes in apolipoprotein E that occur with lipid association. PMID:10850798

  11. cDNA sequences of two apolipoproteins from lamprey

    SciTech Connect

    Pontes, M.; Xu, X.; Graham, D.; Riley, M.; Doolittle, R.F.

    1987-03-24

    The messages for two small but abundant apolipoproteins found in lamprey blood plasma were cloned with the aid of oligonucleotide probes based on amino-terminal sequences. In both cases, numerous clones were identified in a lamprey liver cDNA library, consistent with the great abundance of these proteins in lamprey blood. One of the cDNAs (LAL1) has a coding region of 105 amino acids that corresponds to a 21-residue signal peptide, a putative 8-residue propeptide, and the 76-residue mature protein found in blood. The other cDNA (LAL2) codes for a total of 191 residues, the first 23 of which constitute a signal peptide. The two proteins, which occur in the high-density lipoprotein fraction of ultracentrifuged plasma, have amino acid compositions similar to those of apolipoproteins found in mammalian blood; computer analysis indicates that the sequences are largely helix-permissive. When the sequences were searched against an amino acid sequence data base, rat apolipoprotein IV was the best matching candidate in both cases. Although a reasonable alignment can be made with that sequence and LAL1, definitive assignment of the two lamprey proteins to typical mammalian classes cannot be made at this point.

  12. Polarized secretion of newly synthesized lipoproteins by the Caco-2 human intestinal cell line

    SciTech Connect

    Traber, M.G.; Kayden, H.J.; Rindler, M.J.

    1987-11-01

    Lipoprotein secretion by Caco-2 cells, a human intestinal cell line, was studied in cells grown on inserts containing a Millipore filter (0.45 micron), separating secretory products from the apical and basolateral membranes into separate chambers. Under these conditions, as observed by electron microscopy, the cells formed a monolayer of columnar epithelial cells with microvilli on the apical surface and tight junctions between cells. The electrical resistances of the cell monolayers were 250-500 ohms/cm2. Both /sup 14/C-labeled lipids and /sup 35/S-labeled proteins were used to assess lipoprotein secretion. After a 24-hr incubation with (/sup 14/C)oleic acid, 60-80% of the secreted triglyceride (TG) was in the basolateral chamber; 40% of the TG was present in the d less than 1.006 g/ml (chylomicron + VLDL) fraction and 50% in the 1.006 less than d less than 1.063 g/ml (LDL) fraction. After a 4-hr incubation with (/sup 35/S)methionine, apolipoproteins were found to be major secretory products with 75-100% secreted to the basolateral chamber. Apolipoproteins B-100, B-48, E, A-I, A-IV, and C-III were identified by immunoprecipitation. The d less than 1.006 g/ml fraction was found to contain all of the major apolipoproteins, while the LDL fraction contained primarily apoB-100 and apoE; the HDL (1.063 less than d less than 1.21 g/ml) fraction principally contained apoA-I and apoA-IV. Mn-heparin precipitated all of the (/sup 35/S)methionine-labeled apoB-100 and B-48 and a majority of the other apolipoproteins, and 80% of the (/sup 14/C)oleic acid-labeled triglyceride, but only 15% of the phospholipid, demonstrating that Caco-2 cells secrete triglyceride-rich lipoproteins containing apoB.

  13. Polarized secretion of newly synthesized lipoproteins by the Caco-2 human intestinal cell line.

    PubMed

    Traber, M G; Kayden, H J; Rindler, M J

    1987-11-01

    Lipoprotein secretion by Caco-2 cells, a human intestinal cell line, was studied in cells grown on inserts containing a Millipore filter (0.45 micron), separating secretory products from the apical and basolateral membranes into separate chambers. Under these conditions, as observed by electron microscopy, the cells formed a monolayer of columnar epithelial cells with microvilli on the apical surface and tight junctions between cells. The electrical resistances of the cell monolayers were 250-500 ohms/cm2. Both 14C-labeled lipids and 35S-labeled proteins were used to assess lipoprotein secretion. After a 24-hr incubation with [14C]oleic acid, 60-80% of the secreted triglyceride (TG) was in the basolateral chamber; 40% of the TG was present in the d less than 1.006 g/ml (chylomicron + VLDL) fraction and 50% in the 1.006 less than d less than 1.063 g/ml (LDL) fraction. After a 4-hr incubation with [35S]methionine, apolipoproteins were found to be major secretory products with 75-100% secreted to the basolateral chamber. Apolipoproteins B-100, B-48, E, A-I, A-IV, and C-III were identified by immunoprecipitation. The d less than 1.006 g/ml fraction was found to contain all of the major apolipoproteins, while the LDL fraction contained primarily apoB-100 and apoE; the HDL (1.063 less than d less than 1.21 g/ml) fraction principally contained apoA-I and apoA-IV. Mn-heparin precipitated all of the [35S]methionine-labeled apoB-100 and B-48 and a majority of the other apolipoproteins, and 80% of the [14C]oleic acid-labeled triglyceride, but only 15% of the phospholipid, demonstrating that Caco-2 cells secrete triglyceride-rich lipoproteins containing apoB. Secretion of lipoproteins was dependent on the lipid content of the medium; prior incubation with lipoprotein-depleted serum specifically reduced the secretion of lipoproteins, while addition of both LDL and oleic acid to the medium maintained the level of apoB-100, B-48, and A-IV secretion to that observed in the control

  14. Apolipoprotein D is involved in the mechanisms regulating protection from oxidative stress.

    PubMed

    Ganfornina, Maria D; Do Carmo, Sonia; Lora, Jose M; Torres-Schumann, Sonia; Vogel, Marci; Allhorn, Maria; González, Constancio; Bastiani, Michael J; Rassart, Eric; Sanchez, Diego

    2008-08-01

    Many nervous system pathologies are associated with increased levels of apolipoprotein D (ApoD), a lipocalin also expressed during normal development and aging. An ApoD homologous gene in Drosophila, Glial Lazarillo, regulates resistance to stress, and neurodegeneration in the aging brain. Here we study for the first time the protective potential of ApoD in a vertebrate model organism. Loss of mouse ApoD function increases the sensitivity to oxidative stress and the levels of brain lipid peroxidation, and impairs locomotor and learning abilities. Human ApoD overexpression in the mouse brain produces opposite effects, increasing survival and preventing the raise of brain lipid peroxides after oxidant treatment. These observations, together with its transcriptional up-regulation in the brain upon oxidative insult, identify ApoD as an acute response protein with a protective and therefore beneficial function mediated by the control of peroxidated lipids.

  15. Apolipoprotein D is involved in the mechanisms regulating protection from oxidative stress

    PubMed Central

    Ganfornina, Maria D.; Do Carmo, Sonia; Lora, Jose M.; Torres-Schumann, Sonia; Vogel, Marci; Allhorn, Maria; González, Constancio; Bastiani, Michael J.; Rassart, Eric; Sanchez, Diego

    2008-01-01

    Summary Many nervous system pathologies are associated with increased levels of Apolipoprotein D (ApoD), a lipocalin also expressed during normal development and aging. An ApoD homologous gene in Drosophila, Glial Lazarillo, regulates resistance to stress, and neurodegeneration in the aging brain. Here we study for the first time the protecting potential of ApoD in a vertebrate model organism. Loss of mouse ApoD function increases the sensitivity to oxidative stress and the levels of brain lipid peroxidation, and impairs locomotor and learning abilities. Human ApoD over-expression in the mouse brain produces opposite effects, increasing survival and preventing the raise of brain lipid peroxides after oxidant treatment. These observations, together with its transcriptional up-regulation in the brain upon oxidative insult, identify ApoD as an acute response protein with a protective and therefore beneficial function mediated by the control of peroxidated lipids. PMID:18419796

  16. Influence of apolipoprotein A-V on hepatocyte lipid droplet formation.

    PubMed

    Gao, Xuan; Forte, Trudy M; Ryan, Robert O

    2012-10-19

    Apolipoprotein A-V (apoA-V) is postulated to modulate intra-hepatic triglyceride (TG) trafficking. Stably transfected McA-RH7777 hepatocarcinoma cells expressing human apoA-V displayed enhanced neutral lipid staining while conditioned media from these cells had 40±8% less TG than cells transfected with a control vector. To obtain homogeneous cell lines expressing different amounts of apoA-V, a strategy of clonal selection was pursued. Immunoblot analysis of two distinct apoA-V stable cell lines yielded one that expresses low amounts of apoA-V and another that expresses higher amounts. Confocal fluorescence microscopy of control cells and cells expressing low levels of apoA-V had similar numbers of lipid droplets while cells expressing higher amounts of apoA-V had twice as many lipid droplets, on average. Thus, apoA-V expression promotes lipid droplet accumulation in these cells.

  17. Application of Artificial Intelligence (AI) programming techniques to tactical guidance for fighter aircraft

    NASA Technical Reports Server (NTRS)

    Mcmanus, John W.; Goodrich, Kenneth H.

    1989-01-01

    A research program investigating the use of Artificial Intelligence (AI) programming techniques to aid in the development of a Tactical Decision Generator (TDG) for Within-Visual-Range (WVR) air combat engagements is discussed. The application of AI methods for development and implementation of the TDG is presented. The history of the Adaptive Maneuvering Logic (AML) program is traced and current versions of the (AML) program is traced and current versions of the AML program are compared and contrasted with the TDG system. The Knowledge-Based Systems (KBS) used by the TDG to aid in the decision-making process are outlined and example rules are presented. The results of tests to evaluate the performance of the TDG against a version of AML and against human pilots in the Langley Differential Maneuvering Simulator (DMS) are presented. To date, these results have shown significant performance gains in one-versus-one air combat engagements.

  18. Quality measures and assurance for AI (Artificial Intelligence) software

    NASA Technical Reports Server (NTRS)

    Rushby, John

    1988-01-01

    This report is concerned with the application of software quality and evaluation measures to AI software and, more broadly, with the question of quality assurance for AI software. Considered are not only the metrics that attempt to measure some aspect of software quality, but also the methodologies and techniques (such as systematic testing) that attempt to improve some dimension of quality, without necessarily quantifying the extent of the improvement. The report is divided into three parts Part 1 reviews existing software quality measures, i.e., those that have been developed for, and applied to, conventional software. Part 2 considers the characteristics of AI software, the applicability and potential utility of measures and techniques identified in the first part, and reviews those few methods developed specifically for AI software. Part 3 presents an assessment and recommendations for the further exploration of this important area.

  19. Utilizing AI in Temporal, Spatial, and Resource Scheduling

    NASA Technical Reports Server (NTRS)

    Stottler, Richard; Kalton, Annaka; Bell, Aaron

    2006-01-01

    Aurora is a software system enabling the rapid, easy solution of complex scheduling problems involving spatial and temporal constraints among operations and scarce resources (such as equipment, workspace, and human experts). Although developed for use in the International Space Station Processing Facility, Aurora is flexible enough that it can be easily customized for application to other scheduling domains and adapted as the requirements change or become more precisely known over time. Aurora s scheduling module utilizes artificial-intelligence (AI) techniques to make scheduling decisions on the basis of domain knowledge, including knowledge of constraints and their relative importance, interdependencies among operations, and possibly frequent changes in governing schedule requirements. Unlike many other scheduling software systems, Aurora focuses on resource requirements and temporal scheduling in combination. For example, Aurora can accommodate a domain requirement to schedule two subsequent operations to locations adjacent to a shared resource. The graphical interface allows the user to quickly visualize the schedule and perform changes reflecting additional knowledge or alterations in the situation. For example, the user might drag the activity corresponding to the start of operations to reflect a late delivery.

  20. Intraventricular apolipoprotein ApoJ infusion acts protectively in Traumatic Brain Injury.

    PubMed

    Huang, Zhijian; Cheng, Chongjie; Jiang, Li; Yu, Zhanyang; Cao, Fang; Zhong, Jianjun; Guo, Zongduo; Sun, Xiaochuan

    2016-03-01

    Traumatic brain injury (TBI) is the leading cause of mortality and morbidity in youth, but to date, effective therapies are still lacking. Previous studies revealed a marked response of apolipoprotein J (ApoJ) expression to the brain injury. The aim of this study was to determine the potential roles of ApoJ in functional recovery following TBI. After controlled cortex impact (CCI), a TBI model, in adult wild-type mice, ApoJ expression was up-regulated since 6 h post-injury and sustained for 5 days. Animals infused with recombinant human ApoJ intraventricularly at 30 min prior to CCI showed significantly reduced oxidative stress (3-nitrotyrosine, 4-hydroxynonenal) and complement activation (C5b-9). In addition, ApoJ treatment was shown to suppress the inflammatory response (glial activation, cytokine expression), blood-brain barrier disruption (Evans blue extravasation), and cerebral edema (water content) induced by CCI. Concomitantly, improved neuronal maintenance and neurological behavioral performance were observed in ApoJ-treated mice compared with the vehicle group. These findings support a neuroprotective role of ApoJ via multifunctional pathways, providing a novel and encouraging treatment strategy for TBI. Apolipoprotein J (ApoJ) was up-regulated after controlled cortical impact (CCI). Mice infused with human recombinant ApoJ prior to CCI showed reduced expression of complement and oxidative marker proteins as well as reduced inflammatory response and attenuated blood-brain barrier (BBB) disruption and cerebral edema. Neuronal maintenance and behavioral performance were improved by ApoJ infusion. These findings demonstrated the protective function of ApoJ for traumatic brain injury (TBI) therapy. PMID:26670094

  1. The N-terminus of apolipoprotein A-V adopts a helix bundle molecular architecture.

    PubMed

    Wong, Kasuen; Beckstead, Jennifer A; Lee, Dustin; Weers, Paul M M; Guigard, Emmanuel; Kay, Cyril M; Ryan, Robert O

    2008-08-19

    Previous studies of recombinant full-length human apolipoprotein A-V (apoA-V) provided evidence of the presence of two independently folded structural domains. Computer-assisted sequence analysis and limited proteolysis studies identified an N-terminal fragment as a candidate for one of the domains. C-Terminal truncation variants in this size range, apoA-V(1-146) and apoA-V(1-169), were expressed in Escherichia coli and isolated. Unlike full-length apoA-V or apoA-V(1-169), apoA-V(1-146) was soluble in neutral-pH buffer in the absence of lipid. Sedimentation equilibrium analysis yielded a weight-average molecular weight of 18811, indicating apoA-V(1-146) exists as a monomer in solution. Guanidine HCl denaturation experiments at pH 3.0 yielded a one-step native to unfolded transition that corresponds directly with the more stable component of the two-stage denaturation profile exhibited by full-length apoA-V. On the other hand, denaturation experiments conducted at pH 7.0 revealed a less stable structure. In a manner similar to that of known helix bundle apolipoproteins, apoA-V(1-146) induced a relatively small enhancement in 8-anilino-1-naphthalenesulfonic acid fluorescence intensity. Quenching studies with single-Trp apoA-V(1-146) variants revealed that a unique site predicted to reside on the nonpolar face of an amphipathic alpha-helix was protected from quenching by KI. Taken together, the data suggest the 146 N-terminal residues of human apoA-V adopt a helix bundle molecular architecture in the absence of lipid and, thus, likely exist as an independently folded structural domain within the context of the intact protein.

  2. NASA space station automation: AI-based technology review

    NASA Technical Reports Server (NTRS)

    Firschein, O.; Georgeff, M. P.; Park, W.; Neumann, P.; Kautz, W. H.; Levitt, K. N.; Rom, R. J.; Poggio, A. A.

    1985-01-01

    Research and Development projects in automation for the Space Station are discussed. Artificial Intelligence (AI) based automation technologies are planned to enhance crew safety through reduced need for EVA, increase crew productivity through the reduction of routine operations, increase space station autonomy, and augment space station capability through the use of teleoperation and robotics. AI technology will also be developed for the servicing of satellites at the Space Station, system monitoring and diagnosis, space manufacturing, and the assembly of large space structures.

  3. APOLIPOPROTEINS AND THEIR ASSOCIATION WITH CARDIOMETABOLIC RISK BIOMARKERS IN ADOLESCENTS.

    PubMed

    Neyla de Lima Albuquerque, Mellina; da Silva Diniz, Alcides; Kruze Grande de Arruda, Ilma

    2015-12-01

    Introducción: la razón apo B/apo A-I sigue siendo reportada como un predictor importante de riesgo cardiovascular, superior a lípidos, lipoproteínas y razones lipídicas convencionales. Objetivo: investigar la asociación entre las apolipoproteínas A-I y B y la razón apolipoproteína B/apolipoproteína A-I con variables de riesgo cardiometabólico en adolescentes. Métodos: estudio de corte transversal que incluye a 104 adolescentes de escuelas públicas de Recife, entre marzo/abril de 2013. Se evaluaron variables clínicas, bioquímicas, antropométricas y sociodemográficas. Se analizaron las apolipoproteínas por imunoturbidimetría. Resultados: índice de masa corporal, circunferencia de la cintura, circunferencia de la cintura/altura, triglicéridos, colesterol/HDL y apolipoproteína B/apolipoproteína A-I mostraron una reducción con la progresión de la distribución en percentil de las concentraciones de apolipoproteína A-I, mientras que HDL y apolipoproteína B aumentaron entre el primero y el último cuartil de las concentraciones de apolipoproteína A-I. Tensión arterial sistólica, índice de masa corporal, circunferencia de la cintura, circunferencia de la cintura/altura, colesterol, LDL, triglicéridos, colesterol/HDL y LDL/HDL presentaron un aumento progresivo en la distribución en cuartiles de las concentraciones de apolipoproteína B y de la apolipoproteína B/apolipoproteína A-I. Los niveles séricos de alfa-1-glicoproteína ácida aumentaron paralelamente a la progresión en percentil de apolipoproteína B. Conclusiones: los hallazgos evidencian una asociación importante de las apolipoproteínas A-I y B y de la razón apolipoproteína B/apolipoproteína A-I con biomarcadores clínicos, bioquímicos y antropométricos de riesgo cardiometabólico. Sin embargo, son recomendables estudios prospectivos para evaluar la pertenencia de la implementación de esos marcadores en la práctica clínica.

  4. Calibrating AIS images using the surface as a reference

    NASA Technical Reports Server (NTRS)

    Smith, M. O.; Roberts, D. A.; Shipman, H. M.; Adams, J. B.; Willis, S. C.; Gillespie, A. R.

    1987-01-01

    A method of evaluating the initial assumptions and uncertainties of the physical connection between Airborne Imaging Spectrometer (AIS) image data and laboratory/field spectrometer data was tested. The Tuscon AIS-2 image connects to lab reference spectra by an alignment to the image spectral endmembers through a system gain and offset for each band. Images were calibrated to reflectance so as to transform the image into a measure that is independent of the solar radiant flux. This transformation also makes the image spectra directly comparable to data from lab and field spectrometers. A method was tested for calibrating AIS images using the surface as a reference. The surface heterogeneity is defined by lab/field spectral measurements. It was found that the Tuscon AIS-2 image is consistent with each of the initial hypotheses: (1) that the AIS-2 instrument calibration is nearly linear; (2) the spectral variance is caused by sub-pixel mixtures of spectrally distinct materials and shade, and (3) that sub-pixel mixtures can be treated as linear mixtures of pure endmembers. It was also found that the image can be characterized by relatively few endmembers using the AIS-2 spectra.

  5. Molecular Characterization and Growth Association of Two Apolipoprotein A-Ib Genes in Common Carp (Cyprinus carpio)

    PubMed Central

    Wang, Xinhua; Yu, Xiaomu; Tong, Jingou

    2016-01-01

    Apolipoprotein A-I (ApoA-I) is functionally involved in the transportation and metabolism of lipids in vertebrates. In this study, two isoforms of apoA-Ib in common carp (Cyprinus carpio L.) were characterized. Sequence comparison and phylogenetic analysis showed that C. carpio ApoA-Ib is relatively conserved within cyprinid fishes. During embryonic development, C. carpio apoA-Ib was first expressed at the stage of multi-cells, and the highest mRNA level was observed at the stage of optic vesicle. A ubiquitous expression pattern was detected in various tissues with extreme predominance in the liver. Significantly different expression levels were observed between light and heavy body weight groups and also in the compensatory growth test. Seventeen and eight single-nucleotide polymorphisms (SNPs) were identified in matured mRNA of the C. carpio apoA-Ib.1 and apoA-Ib.2, respectively. Two of these SNPs (apoA-Ib.2-g.183A>T and apoA-Ib.2-g.1753C>T) were significantly associated with body weight and body length in two populations of common carp. These results indicate that apoA-Ib may play an important role in the modulation of growth and development in common carp. PMID:27649163

  6. Analysis of the haptoglobin binding region on the apolipoprotein A-I-derived P2a peptide.

    PubMed

    Spagnuolo, Maria Stefania; Di Stasi, Rossella; De Rosa, Lucia; Maresca, Bernadetta; Cigliano, Luisa; D'Andrea, Luca D

    2013-04-01

    Apolipoprotein A-I (ApoA-I) is the main protein component of the high density lipoproteins and it plays an important role in the reverse cholesterol transport. In particular, it stimulates cholesterol efflux from peripheral cells toward liver and activates the enzyme lecithin-cholesterol acyltransferase (LCAT). Haptoglobin (Hpt), a plasma α2-glycoprotein belonging to the family of acute-phase proteins, binds to ApoA-I inhibiting the stimulation of the enzyme LCAT. Previously, we reported that a synthetic peptide, P2a, binds to and displaces Hpt from ApoA-I restoring the LCAT cholesterol esterification activity in the presence of Hpt. Here, we investigate the molecular determinants underlining the interaction between Hpt and P2a peptide. Analysis of truncated P2a analogs showed that P2a sequence can only be slight reduced in length at the N-terminal to preserve the ability of binding to Hpt. Binding assays showed that charged residues are not involved in Hpt recognition; actually, E146A and D157A substitutions increase the binding affinity to Hpt. Biological characterization of the corresponding P2a peptide analogs, Apo146 and Apo157, showed that the two peptides interfere with Hpt binding to HDL and are more effective than P2a peptide in rescue LCAT activity from Hpt inhibition. This result suggests novel hints to design peptides with anti-atherogenic activity. PMID:23420675

  7. Molecular Characterization and Growth Association of Two Apolipoprotein A-Ib Genes in Common Carp (Cyprinus carpio).

    PubMed

    Wang, Xinhua; Yu, Xiaomu; Tong, Jingou

    2016-01-01

    Apolipoprotein A-I (ApoA-I) is functionally involved in the transportation and metabolism of lipids in vertebrates. In this study, two isoforms of apoA-Ib in common carp (Cyprinus carpio L.) were characterized. Sequence comparison and phylogenetic analysis showed that C. carpio ApoA-Ib is relatively conserved within cyprinid fishes. During embryonic development, C. carpio apoA-Ib was first expressed at the stage of multi-cells, and the highest mRNA level was observed at the stage of optic vesicle. A ubiquitous expression pattern was detected in various tissues with extreme predominance in the liver. Significantly different expression levels were observed between light and heavy body weight groups and also in the compensatory growth test. Seventeen and eight single-nucleotide polymorphisms (SNPs) were identified in matured mRNA of the C. carpio apoA-Ib.1 and apoA-Ib.2, respectively. Two of these SNPs (apoA-Ib.2-g.183A>T and apoA-Ib.2-g.1753C>T) were significantly associated with body weight and body length in two populations of common carp. These results indicate that apoA-Ib may play an important role in the modulation of growth and development in common carp. PMID:27649163

  8. Apolipoprotein L1 Variant Associated with Increased Susceptibility to Trypanosome Infection

    PubMed Central

    Cuypers, Bart; Lecordier, Laurence; Meehan, Conor J.; Van den Broeck, Frederik; Imamura, Hideo; Büscher, Philippe; Dujardin, Jean-Claude; Laukens, Kris; Schnaufer, Achim; Dewar, Caroline; Lewis, Michael; Balmer, Oliver; Azurago, Thomas; Kyei-Faried, Sardick; Ohene, Sally-Ann; Duah, Boateng; Homiah, Prince; Mensah, Ebenezer Kofi; Anleah, Francis; Franco, Jose Ramon; Pays, Etienne

    2016-01-01

    ABSTRACT African trypanosomes, except Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense, which cause human African trypanosomiasis, are lysed by the human serum protein apolipoprotein L1 (ApoL1). These two subspecies can resist human ApoL1 because they express the serum resistance proteins T. b. gambiense glycoprotein (TgsGP) and serum resistance-associated protein (SRA), respectively. Whereas in T. b. rhodesiense, SRA is necessary and sufficient to inhibit ApoL1, in T. b. gambiense, TgsGP cannot protect against high ApoL1 uptake, so different additional mechanisms contribute to limit this uptake. Here we report a complex interplay between trypanosomes and an ApoL1 variant, revealing important insights into innate human immunity against these parasites. Using whole-genome sequencing, we characterized an atypical T. b. gambiense infection in a patient in Ghana. We show that the infecting trypanosome has diverged from the classical T. b. gambiense strains and lacks the TgsGP defense mechanism against human serum. By sequencing the ApoL1 gene of the patient and subsequent in vitro mutagenesis experiments, we demonstrate that a homozygous missense substitution (N264K) in the membrane-addressing domain of this ApoL1 variant knocks down the trypanolytic activity, allowing the trypanosome to avoid ApoL1-mediated immunity. PMID:27073096

  9. Application of Artificial Intelligence (AI) Programming Techniques to Tactical Guidance for Fighter Aircraft

    NASA Technical Reports Server (NTRS)

    McManus, John W.; Goodrich, Kenneth H.

    1989-01-01

    A research program investigating the use of Artificial Intelligence (AI) techniques to aid in the development of a Tactical Decision Generator (TDG) for Within-Visual-Range (WVR) air combat engagements is discussed. The application of AI methods for development and implementation of the TDG is presented. The history of the Adaptive Maneuvering Logic (AML) program is traced and current versions of the AML program are compared and contrasted with the TDG system. The Knowledge-Based Systems (KBS) used by the TDG to aid in the decision-making process are outlined in detail and example rules are presented. The results of tests to evaluate the performance of the TDG versus a version of AML and versus human pilots in the Langley Differential Maneuvering Simulator (DMS) are presented. To date, these results have shown significant performance gains in one-versus-one air combat engagements, and the AI-based TDG software has proven to be much easier to modify than the updated FORTRAN AML programs.

  10. Tryptophan probes reveal residue-specific phospholipid interactions of apolipoprotein C-III.

    PubMed

    Pfefferkorn, Candace M; Walker, Robert L; He, Yi; Gruschus, James M; Lee, Jennifer C

    2015-11-01

    Apolipoproteins are essential human proteins for lipid metabolism. Together with phospholipids, they constitute lipoproteins, nm to μm sized particles responsible for transporting cholesterol and triglycerides throughout the body. To investigate specific protein-lipid interactions, we produced and characterized three single-Trp containing apolipoprotein C-III (ApoCIII) variants (W42 (W54F/W65F), W54 (W42F/W65F), W65 (W42F/W54F)). Upon binding to phospholipid vesicles, wild-type ApoCIII adopts an α-helical conformation (50% helicity) as determined by circular dichroism spectroscopy with an approximate apparent partition constant of 3×10(4) M(-1). Steady-state and time-resolved fluorescence measurements reveal distinct residue-specific behaviors with W54 experiencing the most hydrophobic environment followed by W42 and W65. Interestingly, time-resolved anisotropy measurements show a converse trend for relative Trp mobility with position 54 being the least immobile. To determine the relative insertion depths of W42, W54, and W65 in the bilayer, fluorescence quenching experiments were performed using three different brominated lipids. W65 had a clear preference for residing near the headgroup while W54 and W42 sample the range of depths ~8-11 Å from the bilayer center. On average, W54 is slightly more embedded than W42. Based on Trp spectral differences between ApoCIII binding to phospholipid vesicles and sodium dodecyl sulfate micelles, we suggest that ApoCIII adopts an alternate helical conformation on the bilayer which could have functional implications.

  11. Apolipoprotein D takes center stage in the stress response of the aging and degenerative brain☆

    PubMed Central

    Dassati, Sarah; Waldner, Andreas; Schweigreiter, Rüdiger

    2014-01-01

    Apolipoprotein D (ApoD) is an ancient member of the lipocalin family with a high degree of sequence conservation from insects to mammals. It is not structurally related to other major apolipoproteins and has been known as a small, soluble carrier protein of lipophilic molecules that is mostly expressed in neurons and glial cells within the central and peripheral nervous system. Recent data indicate that ApoD not only supplies cells with lipophilic molecules, but also controls the fate of these ligands by modulating their stability and oxidation status. Of particular interest is the binding of ApoD to arachidonic acid and its derivatives, which play a central role in healthy brain function. ApoD has been shown to act as a catalyst in the reduction of peroxidized eicosanoids and to attenuate lipid peroxidation in the brain. Manipulating its expression level in fruit flies and mice has demonstrated that ApoD has a favorable effect on both stress resistance and life span. The APOD gene is the gene that is upregulated the most in the aging human brain. Furthermore, ApoD levels in the nervous system are elevated in a large number of neurologic disorders including Alzheimer's disease, schizophrenia, and stroke. There is increasing evidence for a prominent neuroprotective role of ApoD because of its antioxidant and anti-inflammatory activity. ApoD emerges as an evolutionarily conserved anti-stress protein that is induced by oxidative stress and inflammation and may prove to be an effective therapeutic agent against a variety of neuropathologies, and even against aging. PMID:24612673

  12. Interaction with amyloid beta peptide compromises the lipid binding function of apolipoprotein E.

    PubMed

    Tamamizu-Kato, Shiori; Cohen, Jenny K; Drake, Carolyn B; Kosaraju, Malathi G; Drury, Jessica; Narayanaswami, Vasanthy

    2008-05-01

    Apolipoprotein (apo) E is an exchangeable apolipoprotein that plays an integral role in cholesterol transport in the plasma and the brain. It is also associated with protein misfolding or amyloid proteopathy of the beta amyloid peptide (Abeta) in Alzheimer's disease (AD) and cerebral amyloid angiopathy. The C-terminal domain (CT) of apoE encompasses two types of amphipathic alpha helices: a class A helix (residues 216-266) and a class G* helix (residues 273-299). This domain also harbors high-affinity lipoprotein binding and apoE self-association sites that possibly overlap. The objective of this study is to examine if the neurotoxic oligomeric Abeta interacts with apoE CT and if this association affects the lipoprotein binding function of recombinant human apoE CT. Site-specific fluorescence labeling of single cysteine-containing apoE CT variants with donor probes were employed to identify the binding of Abeta bearing an acceptor probe by intermolecular fluorescence resonance energy-transfer analysis. A higher efficiency of energy transfer was noted with probes located in the class A helix than with those located in the class G* helix of apoE CT. In addition, incubation of apoE CT with Abeta severely impaired the lipid binding ability and the overall amount of lipid-associated apoE CT. However, when apoE CT is present in a lipid-bound state, Abeta appears to be localized within the lipid milieu of the lipoprotein particle and not associated with any specific segments of the protein. When our data are taken together, they suggest that Abeta association compromises the fundamental lipoprotein binding function of apoE, which may have implications not only in terms of amyloid buildup but also in terms of the accumulation of cholesterol at extracellular sites.

  13. Discovering Knowledge from AIS Database for Application in VTS

    NASA Astrophysics Data System (ADS)

    Tsou, Ming-Cheng

    The widespread use of the Automatic Identification System (AIS) has had a significant impact on maritime technology. AIS enables the Vessel Traffic Service (VTS) not only to offer commonly known functions such as identification, tracking and monitoring of vessels, but also to provide rich real-time information that is useful for marine traffic investigation, statistical analysis and theoretical research. However, due to the rapid accumulation of AIS observation data, the VTS platform is often unable quickly and effectively to absorb and analyze it. Traditional observation and analysis methods are becoming less suitable for the modern AIS generation of VTS. In view of this, we applied the same data mining technique used for business intelligence discovery (in Customer Relation Management (CRM) business marketing) to the analysis of AIS observation data. This recasts the marine traffic problem as a business-marketing problem and integrates technologies such as Geographic Information Systems (GIS), database management systems, data warehousing and data mining to facilitate the discovery of hidden and valuable information in a huge amount of observation data. Consequently, this provides the marine traffic managers with a useful strategic planning resource.

  14. Application of AI techniques to blast furnace operations

    SciTech Connect

    Iida, Osamu; Ushijima, Yuichi; Sawada, Toshiro

    1995-10-01

    It was during the first stages of application of artificial intelligence (AI) to industrial fields, that the ironmaking division of Mizushima works at Kawasaki Steel recognized its potential. Since that time, the division has sought applications for these techniques to solve various problems. AI techniques applied to control the No. 3 blast furnace operations at the Mizushima works include: Blast furnace control by a diagnostic type of expert system that gives guidance to the actions required for blast furnace operation as well as control of furnace heat by automatically setting blast temperature; Hot stove combustion control by a combination of fuzzy inference and a physical model to insure good thermal efficiency of the stove; and blast furnace burden control using neural networks makes it possible to connect the pattern of gas flow distribution with the condition of the furnace. Experience of AI to control the blast furnace and other ironmaking operations has proved its capability for achieving automation and increased operating efficiency. The benefits are very high. For these reasons, the applications of AI techniques will be extended in the future and new techniques studied to further improve the power of AI.

  15. Nonreplication of an Association of Apolipoprotein E2 With Sinistrality

    PubMed Central

    Piper, Brian J.; Yasen, Alia L.; Taylor, Amy E.; Ruiz, Jonatan R.; Gaynor, J. William; Dayger, Catherine A.; Gonzalez-Gross, Marcela; Kwon, Oh D.; Nilsson, Lars-Göran; Day, Ian N. M.; Raber, Jacob; Miller, Jeremy K.

    2013-01-01

    A recent report found that left-handed adolescents were over three-fold more likely to have an Apolipoprotein (APOE) ε2 allele. This study was unable to replicate this association in young-adults (N=166). A meta-analysis of nine other datasets (N = 360 to 7,559, Power > 0.999) including that of National Alzheimer’s Coordinating Center also failed to find an over-representation of ε2 among left-handers indicating that this earlier outcome was most likely a statistical artifact. PMID:22721421

  16. Multiple reaction monitoring and multiple reaction monitoring cubed based assays for the quantitation of apolipoprotein F.

    PubMed

    Kumar, Abhinav; Gangadharan, Bevin; Zitzmann, Nicole

    2016-10-15

    Apolipoprotein F (APO-F) is a novel low abundance liver fibrosis biomarker and its concentration decreases in human serum and plasma across liver fibrosis stages. Current antibody based assays for APO-F suffer from limitations such as unspecific binding, antibody availability and undetectable target if the protein is degraded; and so an antibody-free assay has the potential to be a valuable diagnostic tool. We report an antibody-free, rapid, sensitive, selective and robust LC-MS/MS (MRM and MRM(3)) method for the detection and quantitation of APO-F in healthy human plasma. With further analysis of clinical samples, this LC-MS based method could be established as the first ever antibody-free biomarker assay for liver fibrosis. We explain the use of Skyline software for peptide selection and the creation of a reference library to aid in true peak identification of endogenous APO-F peptides in digests of human plasma without protein or peptide enrichment. Detection of a glycopeptide using MRM-EPI mode and reduction of interferences using MRM3 are explained. The amount of APO-F in human plasma from a healthy volunteer was determined to be 445.2ng/mL, the coefficient of variation (CV) of precision for 20 injections was <12% and the percentage error of each point along the calibration curve was calculated to be <8%, which is in line with the assay requirements for clinical samples. PMID:27592286

  17. An ultrasensitive electrochemical immunosensor for apolipoprotein E4 based on fractal nanostructures and enzyme amplification.

    PubMed

    Liu, Yibiao; Xu, Li-Ping; Wang, Shuqi; Yang, Weizhao; Wen, Yongqiang; Zhang, Xueji

    2015-09-15

    Human apolipoprotein E4 (APOE4) is a major risk factor for Alzheimer's disease (AD) and can greatly increase the morbidity. In this work, an ultrasensitive sandwich-type electrochemical immunosensor for the quantitative detection of APOE4 was designed based on fractal gold (FracAu) nanostructures and enzyme amplification. The FracAu nanostructures were directly electrodeposited by hydrogen tetrachloroaurate (HAuCl4) on polyelectrolytes modified indium tin oxide (ITO) electrode. The sensing performances of the modified interface were investigated by cyclic voltammetry (CV). After functionalization with HRP-labeled APOE4 antibody, the human APOE4 could be detected quantitatively by current response. The current response has a linear relationship with the logarithm of human APOE4 concentrations in a range from 1.0 to 10,000.0 ng/mL, with a detection limit of 0.3 ng/mL. The fabricated APOE4 electrochemical immunosensor exhibits strong specificity, high sensitivity, low detection limit and wide linear range. The detection of human APOE4 provides a strong support for the prevention of AD and early-stage warning for those susceptible populations.

  18. Multiple reaction monitoring and multiple reaction monitoring cubed based assays for the quantitation of apolipoprotein F.

    PubMed

    Kumar, Abhinav; Gangadharan, Bevin; Zitzmann, Nicole

    2016-10-15

    Apolipoprotein F (APO-F) is a novel low abundance liver fibrosis biomarker and its concentration decreases in human serum and plasma across liver fibrosis stages. Current antibody based assays for APO-F suffer from limitations such as unspecific binding, antibody availability and undetectable target if the protein is degraded; and so an antibody-free assay has the potential to be a valuable diagnostic tool. We report an antibody-free, rapid, sensitive, selective and robust LC-MS/MS (MRM and MRM(3)) method for the detection and quantitation of APO-F in healthy human plasma. With further analysis of clinical samples, this LC-MS based method could be established as the first ever antibody-free biomarker assay for liver fibrosis. We explain the use of Skyline software for peptide selection and the creation of a reference library to aid in true peak identification of endogenous APO-F peptides in digests of human plasma without protein or peptide enrichment. Detection of a glycopeptide using MRM-EPI mode and reduction of interferences using MRM3 are explained. The amount of APO-F in human plasma from a healthy volunteer was determined to be 445.2ng/mL, the coefficient of variation (CV) of precision for 20 injections was <12% and the percentage error of each point along the calibration curve was calculated to be <8%, which is in line with the assay requirements for clinical samples.

  19. Apolipoprotein gene involved in lipid metabolism

    DOEpatents

    Rubin, Edward; Pennacchio, Len A.

    2007-07-03

    Methods and materials for studying the effects of a newly identified human gene, APOAV, and the corresponding mouse gene apoAV. The sequences of the genes are given, and transgenic animals which either contain the gene or have the endogenous gene knocked out are described. In addition, single nucleotide polymorphisms (SNPs) in the gene are described and characterized. It is demonstrated that certain SNPs are associated with diseases involving lipids and triglycerides and other metabolic diseases. These SNPs may be used alone or with SNPs from other genes to study individual risk factors. Methods for intervention in lipid diseases, including the screening of drugs to treat lipid-related or diabetic diseases are also disclosed.

  20. Automated AI-based designer of electrical distribution systems

    NASA Astrophysics Data System (ADS)

    Sumic, Zarko

    1992-03-01

    Designing the electrical supply system for new residential developments (plat design) is an everyday task for electric utility engineers. Presently this task is carried out manually resulting in an overdesigned, costly, and nonstandardized solution. As an ill-structured and open-ended problem, plat design is difficult to automate with conventional approaches such as operational research or CAD. Additional complexity in automating plat design is imposed by the need to process spatial data such as circuits' maps, records, and construction plans. The intelligent decision support system for automated electrical plate design (IDSS for AEPD) is an engineering tool aimed at automating plate design. IDSS for AEPD combines the functionality of geographic information systems (GIS) a geographically referenced database, with the sophistication of artificial intelligence (AI) to deal with the complexity inherent in design problems. Blackboard problem solving architecture, concentrated around INGRES relational database and NEXPERT object expert system shell have been chosen to accommodate the diverse knowledge sources and data models. The GIS's principal task it to create, structure, and formalize the real world representation required by the rule based reasoning portion of the AEPD. IDSS's capability to support and enhance the engineer's design, rather than only automate the design process through a prescribed computation, makes it a preferred choice among the possible techniques for AEPD. This paper presents the results of knowledge acquisition and the knowledge engineering process with AEPD tool conceptual design issues. To verify the proposed concept, the comparison of results obtained by the AEPD tool with the design obtained by an experienced human designer is given.

  1. Identification of the ancestral haplotype for apolipoprotein B suggests an African origin of Homo sapiens sapiens and traces their subsequent migration to Europe and the Pacific

    SciTech Connect

    Rapacz, J.; Hasler-Rapacz, J.O. ); Chen, L.; Wu, Mingjiuan; Schumaker, V.N. ); Butler-Brunner, E.; Butler, R. )

    1991-02-15

    The probable ancestral haplotype for human apolipoprotein B (apoB) has been identified through immunological analysis of chimpanzee and gorilla serum and sequence analysis of their DNA. Moreover, the frequency of this ancestral apoB haplotype among different human populations provides strong support for the African origin of Homo sapiens sapiens and their subsequent migration from Africa to Europe and to the Pacific. The approach used here for the identification of the ancestral human apoB haplotype is likely to be applicable to many other genes.

  2. Identification of the ancestral haplotype for apolipoprotein B suggests an African origin of Homo sapiens sapiens and traces their subsequent migration to Europe and the Pacific.

    PubMed Central

    Rapacz, J; Chen, L; Butler-Brunner, E; Wu, M J; Hasler-Rapacz, J O; Butler, R; Schumaker, V N

    1991-01-01

    The probable ancestral haplotype for human apolipoprotein B (apoB) has been identified through immunological analysis of chimpanzee and gorilla serum and sequence analysis of their DNA. Moreover, the frequency of this ancestral apoB haplotype among different human populations provides strong support for the African origin of Homo sapiens sapiens and their subsequent migration from Africa to Europe and to the Pacific. The approach used here for the identification of the ancestral human apoB haplotype is likely to be applicable to many other genes. PMID:1996341

  3. Identification of the ancestral haplotype for apolipoprotein B suggests an African origin of Homo sapiens sapiens and traces their subsequent migration to Europe and the Pacific.

    PubMed

    Rapacz, J; Chen, L; Butler-Brunner, E; Wu, M J; Hasler-Rapacz, J O; Butler, R; Schumaker, V N

    1991-02-15

    The probable ancestral haplotype for human apolipoprotein B (apoB) has been identified through immunological analysis of chimpanzee and gorilla serum and sequence analysis of their DNA. Moreover, the frequency of this ancestral apoB haplotype among different human populations provides strong support for the African origin of Homo sapiens sapiens and their subsequent migration from Africa to Europe and to the Pacific. The approach used here for the identification of the ancestral human apoB haplotype is likely to be applicable to many other genes. PMID:1996341

  4. Altered small-world anatomical networks in Apolipoprotein-E4 (ApoE4) carriers using MRI.

    PubMed

    Goryawala, Mohammed; Zhou, Qi; Duara, Ranjan; Loewenstein, David; Cabrerizo, Mercedes; Barker, Warren; Adjouadi, Malek

    2014-01-01

    Apolipoprotein E (ApoE) gene and primarily its allele e4 have been identified as a risk factor for Alzheimer's disease (AD). The prevalence of the gene in 25-30% in the population makes it essential to estimate its role in neuroregulation and its impact on distributed brain networks. In this study, we provide computational neuroanatomy based interpretation of large-scale and small-world cortical networks in cognitive normal (CN) subjects with differing Apolipoprotein-E4 (ApoE4) gene expression. We estimated large-scale anatomical networks from cortical thickness measurements derived from magnetic resonance imaging in 147 CN subjects explored in relation to ApoE4 genotype (e4+ carriers (n=41) versus e4- non-carriers (n=106)). Brain networks were constructed by thresholding cortical thickness correlation matrices of 68 bilateral regions of the brain analyzed using well-established graph theoretical approaches. Compared to ApoE4 non-carriers, carriers showed increased interregional correlation coefficients in regions like precentral, superior frontal and inferior temporal regions. Interestingly most of the altered connections were intra-hemispheric limited primarily to the right hemisphere. Furthermore, ApoE4 carriers demonstrated abnormal small-world architecture in the cortical networks with increased clustering coefficient and path lengths as compared to non-carrier, suggesting a less optimal topological organization. Additionally non-carriers demonstrated higher betweenness in regions such as middle temporal, para-hippocampal gyrus, posterior cingulate and insula of the default mode network (DMN), also seen in subjects with AD and mild cognitive impairment (MCI). The results suggest that the complex morphological cortical connectivity patterns are altered in ApoE4 carriers as compared to non-carriers, providing evidence for disruption of integrity in large-scale anatomical brain networks.

  5. Effects of blackberry (Morus nigra L.) consumption on serum concentration of lipoproteins, apo A-I, apo B, and high-sensitivity-C-reactive protein and blood pressure in dyslipidemic patients

    PubMed Central

    Aghababaee, Sahar Keshtkar; Vafa, Mohammadreza; Shidfar, Farzad; Tahavorgar, Atefeh; Gohari, Mahmoodreza; Katebi, Davod; Mohammadi, Vida

    2015-01-01

    Background: This study investigated blackberry (Persian mulberry) effects on apo A-I, apo B, high-sensitivity-C-reactive protein (hs-CRP), and systolic blood pressure (SBP) and diastolic blood pressure (DBP) in dyslipidemic patients. Materials and Methods: In this 8-week randomized clinical trial, 72 dyslipidemic patients were randomly divided into two groups: Intervention (300 mL/day blackberry juice with pulp) and control group (usual diets). Before and after the intervention, fasting blood samples were taken from both groups and serum concentration of lipoprotein, apo A-I and apo B, serum lipids (total cholesterol, low-density lipoprotein, high-density lipoprotein [HDL], and triglyceride), hs-CRP were measured. Blood pressure before and after the study was measured with a mercury manometer. Results: At week 8 in the intervention group, apo A-I and HDL increased significantly (P = 0.015, P = 0.001, respectively), apo B and hs-CRP decreased significantly (P = 0.044, P = 0.04, respectively). Mean changes in apo A-I and HDL and apo B/apo A-I ratio were significant between the groups (P = 0.005, P = 0.014, and P = 0.009, respectively). After 8 weeks, there was a significant difference between hs-CRP mean values (P = 0.01) of the groups. At week 8, SBP decreased significantly (P = 0.005) in the intervention group with no significant differences for SBP mean values between the groups. No significant changes were observed in other lipid parameters and DBP in the intervention group and between the groups. Conclusion: Blackberry consumption may exert beneficial effects on apolipoproteins, blood pressure, and inflammatory markers in individuals with lipid disorders. PMID:26622259

  6. The intravenous injection of oxidized LDL- or Apolipoprotein B100 – Coupled splenocytes promotes Th1 polarization in wildtype and Apolipoprotein E – Deficient mice

    SciTech Connect

    Steinmetz, Martin; Ponnuswamy, Padmapriya; Laurans, Ludivine; Esposito, Bruno; Tedgui, Alain; Mallat, Ziad

    2015-08-14

    Background: Th1 responses in atherosclerosis are mainly associated with the aggravation of atherosclerotic plaques, whereas Th2 responses lead to a less pronounced disease in mouse models. The fixation of antigens on cells by means of ethylene carbodiimide (ECDI), and subsequent injection of these antigen-coupled splenocytes (Ag-SP) to induce tolerance against the attached antigens, has been successfully used to treat murine type 1 diabetes or encephalomyelitis in. We analyzed this approach in a mouse model for atherosclerosis. Methods and results: OTII-transgenic mice that were treated with a single dose of 5 × 10{sup 7} OVA-coupled splenocytes (OVA-SP), had decreased splenocyte proliferation, and lower IFNγ production in vitro upon antigen recall. However, in vivo CD4 cell activation was increased. To try lipoprotein-derived, “atherosclerosis-associated” antigens, we first tested human oxidized LDL. In wild type mice, an increase of IFNγ production upon in vitro recall was detected in the oxLDL-SP group. In Apolipoprotein E − deficient (ApoE−/−) mice that received oxLDL-SP every 5 weeks for 20 weeks, we did not find any difference of atherosclerotic plaque burden, but again increased IFNγ production. To overcome xenogenous limitations, we then examined the effects of mouse Apolipoprotein B100 peptides P3 and P6. ApoB100-SP treatment again promoted a more IFNγ pronounced response upon in vitro recall. Flow cytometry analysis of cytokine secreting spleen cells revealed CD4 positive T cells to be mainly the source for IFNγ. In ApoE−/− mice that were administered ApoB100-SP during 20 weeks, the atherosclerotic plaque burden in aortic roots as well as total aorta was unchanged compared to PBS treated controls. Splenocyte proliferation upon antigen recall was not significantly altered in ApoB100-SP treated ApoE−/− mice. Conclusion: Although we did not observe a relevant anti-atherosclerotic benefit, the treatment with antigen

  7. Toward detecting California shrubland canopy chemistry with AIS data

    NASA Technical Reports Server (NTRS)

    Price, Curtis V.; Westman, Walter E.

    1987-01-01

    Airborne Imaging Spectrometer (AIS)-2 data of coastal sage scrub vegetation were examined for fine spectral features that might be used to predict concentrations of certain canopy chemical constituents. A Fourier notch filter was applied to the AIS data and the TREE and ROCK mode spectra were ratioed to a flat field. Portions of the resulting spectra resemble spectra for plant cellulose and starch in that both show reduced reflectance at 2100 and 2270 nm. The latter are regions of absorption of energy by organic bonds found in starch and cellulose. Whether the relationship is sufficient to predict the concentration of these chemicals from AIS spectra will require testing of the predictive ability of these wavebands with large field sample sizes.

  8. Artificial intelligence (AI) based tactical guidance for fighter aircraft

    NASA Technical Reports Server (NTRS)

    Mcmanus, John W.; Goodrich, Kenneth H.

    1990-01-01

    A research program investigating the use of artificial intelligence (AI) techniques to aid in the development of a Tactical Decision Generator (TDG) for Within Visual Range air combat engagements is discussed. The application of AI programming and problem solving methods in the development and implementation of the Computerized Logic For Air-to-Air Warfare Simulations (CLAWS), a second generation TDG, is presented. The knowledge-based systems used by CLAWS to aid in the tactical decision-making process are outlined in detail, and the results of tests to evaluate the performance of CLAWS versus a baseline TDG developed in FORTRAN to run in real time in the Langley Differential Maneuvering Simulator, are presented. To date, these test results have shown significant performance gains with respect to the TDG baseline in one-versus-one air combat engagements, and the AI-based TDG software has proven to be much easier to modify and maintain than the baseline FORTRAN TDG programs.

  9. Serum cholesterol and expression of ApoAI, LXRbeta and SREBP2 in vitamin D receptor knock-out mice.

    PubMed

    Wang, Jing-Huan; Keisala, Tiina; Solakivi, Tiina; Minasyan, Anna; Kalueff, Allan V; Tuohimaa, Pentti

    2009-02-01

    Vitamin D insufficiency has been reported to be associated with increased blood cholesterol concentrations. Here we used two strains of VDR knock-out (VDR-KO) mice to study whether a lack of vitamin D action has any effect on cholesterol metabolism. In 129S1 mice, both in male and female VDR-KO mice serum total cholesterol levels were significantly higher than those in wild type (WT) mice (20.7% (P=0.05) and 22.2% (P=0.03), respectively). In addition, the serum high-density lipoprotein-bound cholesterol (HDL-C) level was 22% (P=0.03), respectively higher in male VDR-KO mice than in WT mice. The mRNA expression levels of five cholesterol metabolism related genes in livers of 129S1 mice were studied using quantitative real-time PCR (QRT-PCR): ATP-binding cassette transporter A1 (ABCA1), regulatory element binding protein (SREBP2), apolipoprotein A-I (ApoAI), low-density lipoprotein receptor (LDLR) and liver X receptor beta (LXRbeta). In the mutant male mice, the mRNA level of ApoAI and LXRbeta were 49.2% (P=0.005) and 38.8% (P=0.034) higher than in the WT mice. These changes were not observed in mutant female mice, but the female mutant mice showed 52.5% (P=0.006) decrease of SREBP2 mRNA expression compared to WT mice. Because the mutant mice were fed with a special rescue diet, we wanted to test whether the increased cholesterol levels in mutant mice were due to the diet. Both the WT and mutant NMRI mice were given the same diet for 3 weeks before the blood sampling. No difference in cholesterol or in HDL-C between WT and mutant mice was found. The results suggest that the food, gender and genetic background have an effect on the cholesterol metabolism. Although VDR seems to regulate some of the genes involved in cholesterol metabolism, its role in the regulation of serum cholesterol seems to be minimal.

  10. Validation of the ICD/AIS MAP for pediatric use

    PubMed Central

    Durbin, D; Localio, A; MacKenzie, E

    2001-01-01

    Objective—To determine the performance of the ICD/AIS MAP (© E J MacKenzie et al) as a method of classifying injury severity for children. Methods—Data on all children less than 16 years of age admitted to all designated trauma centers in Pennsylvania from January 1994 through October 1996 were obtained from the state trauma registry. The ICD/AIS MAP was used to convert all injury related ICD-9-CM diagnosis codes into abbreviated injury scale (AIS) score and injury severity score (ISS). Agreement between trauma registry AIS and ISS scores and MAP generated scores was assessed using the weighted κ (κw) coefficient for ordered data and the intraclass correlation coefficient for continuous data. Results—Agreement in ISS scores was excellent, both overall (intraclass correlation coefficient = 0.86, 95% confidence interval (CI) 0.84 to 0.89)), and when grouped into three levels of severity (κw= 0.86, 95% CI 0.85 to 0.87). Agreement in AIS scores across all body regions and ages was also excellent, (κw= 0.86 (95% CI 0.83 to 0.87). Agreement increased with age (κw= 0.78 for children <2 years; κw= 0.86 for older children) and varied by body region, though was excellent across all regions. Conclusions—The performance of the ICD/AIS MAP in assessing severity of pediatric injuries was equal to or better than previous assessments of its performance on primarily adult patients. Its performance was excellent across the pediatric age range and across nearly all body regions of injury. PMID:11428572

  11. [The Abbreviated Injury Scale (AIS). Options and problems in application].

    PubMed

    Haasper, C; Junge, M; Ernstberger, A; Brehme, H; Hannawald, L; Langer, C; Nehmzow, J; Otte, D; Sander, U; Krettek, C; Zwipp, H

    2010-05-01

    The new AIS (Abbreviated Injury Scale) was released with an update by the AAAM (Association for the Advancement of Automotive Medicine) in 2008. It is a universal scoring system in the field of trauma applicable in clinic and research. In engineering it is used as a classification system for vehicle safety. The AIS can therefore be considered as an international, interdisciplinary and universal code of injury severity. This review focuses on a historical overview, potential applications and new coding options in the current version and also outlines the associated problems. PMID:20376615

  12. Application of AI technology to nuclear plant operations

    SciTech Connect

    Sackett, J.I.

    1988-01-01

    In this paper, applications of Artificial Intelligence (AI) Technology to nuclear-power plant operation are reviewed. AI Technology is advancing rapidly and in the next five years is expected to enjoy widespread application to operation, maintenance, management and safety. Near term emphasis on a sensor validation, scheduling, alarm handling, and expert systems for procedural assistance. Ultimate applications are envisioned to culminate in autonomous control such as would be necessary for a power system in space, where automatic control actions are taken based upon reasoned conclusions regarding plant conditions, capability and control objectives.

  13. Rapid prototyping and AI programming environments applied to payload modeling

    NASA Technical Reports Server (NTRS)

    Carnahan, Richard S., Jr.; Mendler, Andrew P.

    1987-01-01

    This effort focused on using artificial intelligence (AI) programming environments and rapid prototyping to aid in both space flight manned and unmanned payload simulation and training. Significant problems addressed are the large amount of development time required to design and implement just one of these payload simulations and the relative inflexibility of the resulting model to accepting future modification. Results of this effort have suggested that both rapid prototyping and AI programming environments can significantly reduce development time and cost when applied to the domain of payload modeling for crew training. The techniques employed are applicable to a variety of domains where models or simulations are required.

  14. AiGERM: A logic programming front end for GERM

    NASA Technical Reports Server (NTRS)

    Hashim, Safaa H.

    1990-01-01

    AiGerm (Artificially Intelligent Graphical Entity Relation Modeler) is a relational data base query and programming language front end for MCC (Mission Control Center)/STP's (Space Test Program) Germ (Graphical Entity Relational Modeling) system. It is intended as an add-on component of the Germ system to be used for navigating very large networks of information. It can also function as an expert system shell for prototyping knowledge-based systems. AiGerm provides an interface between the programming language and Germ.

  15. Diverter AI based decision aid, phases 1 and 2

    NASA Technical Reports Server (NTRS)

    Sexton, George A.; Bayles, Scott J.; Patterson, Robert W.; Schulke, Duane A.; Williams, Deborah C.

    1989-01-01

    It was determined that a system to incorporate artificial intelligence (AI) into airborne flight management computers is feasible. The AI functions that would be most useful to the pilot are to perform situational assessment, evaluate outside influences on the contemplated rerouting, perform flight planning/replanning, and perform maneuver planning. A study of the software architecture and software tools capable of demonstrating Diverter was also made. A skeletal planner known as the Knowledge Acquisition Development Tool (KADET), which is a combination script-based and rule-based system, was used to implement the system. A prototype system was developed which demonstrates advanced in-flight planning/replanning capabilities.

  16. Conformational mimicry in Alzheimer's disease. Role of apolipoproteins in amyloidogenesis.

    PubMed Central

    Wisniewski, T.; Golabek, A. A.; Kida, E.; Wisniewski, K. E.; Frangione, B.

    1995-01-01

    Several apolipoproteins are known to be closely associated with amyloid fibrillogenesis. Serum amyloid A, apolipoprotein (apo) AII and apo A1 are each deposited as biochemically distinct forms of amyloid. Late-onset Alzheimer's disease is linked to one isotype of apo E, apo E4. Apo E and apo E4 in particular have been shown to modulate amyloid fibril formation by amyloid-beta peptides in vitro. Furthermore, the carboxy terminus of apo E has been shown to be a constituent of plaque amyloid. We show immunohistochemically and electron microscopically the presence of apo A1 in senile plaques. The intact apo A1 can itself form amyloid-like fibrils in vitro that are Congo Red positive. We propose that some proteins when misfolded can propagate this misfolding to identical units, either autocatalytically or to other proteins that are induced to fold into the same abnormal conformation. This conformational mimicry may initiate and/or augment fibrillogenesis in Alzheimer's disease. Images Figure 1 Figure 3 Figure 2 PMID:7639323

  17. Amphotericin B induced interdigitation of apolipoprotein stabilized nanodisk bilayers

    SciTech Connect

    Nguyen, T; Weers, P M; Sulchek, T; Hoeprich, P D; Ryan, R O

    2006-12-07

    Amphotericin B nanodisks (AMB-ND) are ternary complexes of AMB, phospholipid (PL) and apolipoprotein organized as discrete nanometer scale disk-shaped bilayers. In gel filtration chromatography experiments, empty ND lacking AMB elute as a single population of particles with a molecular weight in the range of 200 kDa. AMB-ND formulated at a 4:1 PL:AMB weight ratio, separated into two peaks. Peak 1 eluted at the position of control ND lacking AMB while the second peak, containing all of the AMB present in the original sample, eluted in the void volume. When ND prepared with increased AMB (1:1 phospholipid:AMB molar ratio) were subjected to gel filtration chromatography, an increased proportion of phospholipid and apolipoprotein were recovered in the void volume with the AMB. Prior to gel filtration the AMB-ND sample could be passed through a 0.22 {micro}m filter without loss of AMB while the voided material was lost. Native gel electrophoresis studies corroborated the gel permeation chromatography data. Far UV circular dichroism analyses revealed that apoA-I associated with AMB-ND denatures at a lower guanidine HCl concentration than apoA-I associated with ND lacking AMB. Atomic force microscopy revealed that AMB induces compression of the ND bilayer thickness consistent with bilayer interdigitation, a phenomenon that is likely related to the ability of AMB to induce pore formation in susceptible membranes.

  18. Absence of apolipoprotein E protects mice from cerebral malaria.

    PubMed

    Kassa, Fikregabrail Aberra; Van Den Ham, Kristin; Rainone, Anthony; Fournier, Sylvie; Boilard, Eric; Olivier, Martin

    2016-01-01

    Cerebral malaria claims the life of millions of people each year, particularly those of children, and is a major global public health problem. Thus, the identification of novel malaria biomarkers that could be utilized as diagnostic or therapeutic targets is becoming increasingly important. Using a proteomic approach, we previously identified unique biomarkers in the sera of malaria-infected individuals, including apolipoprotein E (ApoE). ApoE is the dominant apolipoprotein in the brain and has been implicated in several neurological disorders; therefore, we were interested in the potential role of ApoE in cerebral malaria. Here we report the first demonstration that cerebral malaria is markedly attenuated in ApoE(-/-) mice. The protection provided by the absence of ApoE was associated with decreased sequestration of parasites and T cells within the brain, and was determined to be independent from the involvement of ApoE receptors and from the altered lipid metabolism associated with the knock-out mice. Importantly, we demonstrated that treatment of mice with the ApoE antagonist heparin octasaccharide significantly decreased the incidence of cerebral malaria. Overall, our study indicates that the reduction of ApoE could be utilized in the development of therapeutic treatments aimed at mitigating the neuropathology of cerebral malaria. PMID:27647324

  19. Absence of apolipoprotein E protects mice from cerebral malaria

    PubMed Central

    Kassa, Fikregabrail Aberra; Van Den Ham, Kristin; Rainone, Anthony; Fournier, Sylvie; Boilard, Eric; Olivier, Martin

    2016-01-01

    Cerebral malaria claims the life of millions of people each year, particularly those of children, and is a major global public health problem. Thus, the identification of novel malaria biomarkers that could be utilized as diagnostic or therapeutic targets is becoming increasingly important. Using a proteomic approach, we previously identified unique biomarkers in the sera of malaria-infected individuals, including apolipoprotein E (ApoE). ApoE is the dominant apolipoprotein in the brain and has been implicated in several neurological disorders; therefore, we were interested in the potential role of ApoE in cerebral malaria. Here we report the first demonstration that cerebral malaria is markedly attenuated in ApoE−/− mice. The protection provided by the absence of ApoE was associated with decreased sequestration of parasites and T cells within the brain, and was determined to be independent from the involvement of ApoE receptors and from the altered lipid metabolism associated with the knock-out mice. Importantly, we demonstrated that treatment of mice with the ApoE antagonist heparin octasaccharide significantly decreased the incidence of cerebral malaria. Overall, our study indicates that the reduction of ApoE could be utilized in the development of therapeutic treatments aimed at mitigating the neuropathology of cerebral malaria. PMID:27647324

  20. Amphotericin B induces interdigitation of apolipoprotein stabilized nanodisk bilayers.

    PubMed

    Nguyen, Thanh-Son; Weers, Paul M M; Raussens, Vincent; Wang, Zhen; Ren, Gang; Sulchek, Todd; Hoeprich, Paul D; Ryan, Robert O

    2008-01-01

    Amphotericin B nanodisks (AMB-ND) are ternary complexes of AMB, phospholipid and apolipoprotein organized as discrete nanometer scale disk-shaped bilayers. In gel filtration chromatography experiments, empty ND lacking AMB elute as a single population of particles with a molecular weight in the range of 200 kDa. AMB-ND formulated at a 4:1 phospholipid:AMB weight ratio separated into two peaks. One peak eluted at the position of control ND lacking AMB while the second peak, containing all of the AMB present in the original sample, eluted in the void volume. When ND prepared with increased AMB were subjected to gel filtration chromatography an increased proportion of phospholipid and apolipoprotein was recovered in the void volume with AMB. Native gradient gel electrophoresis corroborated the gel filtration chromatography data and electron microscopy studies revealed an AMB concentration-dependent heterogeneity in ND particle size. Stability studies revealed that introduction of AMB into ND decreases the ability of apoA-I to resist denaturation. Atomic force microscopy experiments showed that AMB induces compression of ND bilayer thickness while infrared spectroscopy analysis revealed that the presence of AMB does not induce extreme lipid disorder or alter the mean angle of the molecular axis along fatty acyl chains of ND phospholipids. Taken together the results are consistent with AMB-induced bilayer interdigitation, a phenomenon that likely contributes to AMB-dependent pore formation in susceptible membranes.

  1. Targeting Apolipoproteins in Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Sriram, Renuka; Lagerstedt, Jens O.; Samardzic, Haris; Kreutzer, Ulrike; Petrolova, Jitka; Xie, Hongtao; Kaysen, George A.; Voss, John C.; Desreux, Jean F.; Jue, Thomas

    Maintaining normal physiological homeostasis depends upon a coordinated metabolism of both water-soluble and -insoluble substrates. In humans the body derives these molecules — such as glucose, amino acids, and fatty acids — from complex food matter. Water-soluble substrates can ci