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Sample records for apolipoprotein-e forms dimers

  1. Apolipoprotein E forms stable complexes with recombinant Alzheimer's disease beta-amyloid precursor protein.

    PubMed Central

    Haas, C; Cazorla, P; Miguel, C D; Valdivieso, F; Vázquez, J

    1997-01-01

    Apolipoprotein E (apoE), a protein genetically linked to the incidence of Alzheimer's disease, forms SDS-stable complexes in vitro with beta-amyloid peptide (Abeta), the primary component of senile plaques. In the present study, we investigated whether apoE was able to bind full-length Abeta precursor protein (APP). Using a maltose-binding-protein-APP fusion protein and human very-low-density lipoprotein (VLDL), we detected an interaction of apoE with APP that was inhibited by Abeta or anti-apoE antibody. Saturation-binding experiments indicated a single binding equilibrium with an apparent 1:1 stoichiometry and a dissociation constant of 15 nM. An interaction was also observed using apoE from cerebrospinal fluid or delipidated VLDL, as well as recombinant apoE. APP.apoE complexes were SDS-stable, and their formation was not inhibited by reducing conditions; however, they were dissociated by SDS under reducing conditions. ApoE.APP complexes formed high-molecular-mass aggregates, and competition experiments suggested that amino acids 14-23 of Abeta are responsible for complex-formation. Finally, no differences were found when studying the interaction of APP with apoE3 or apoE4. Taken together, our results demonstrate that apoE may form stable complexes with the Abeta moiety of APP with characteristics similar to those of complexes formed with isolated Abeta, and suggest the intriguing possibility that apoE-APP interactions may be pathologically relevant in vivo. PMID:9224643

  2. 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

  3. 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.

  4. Role of apolipoprotein E in febrile convulsion.

    PubMed

    Giray, Ozlem; Ulgenalp, Ayfer; Bora, Elçin; Uran, Nedret; Yilmaz, Ebru; Unalp, Aycan; Erçal, Derya

    2008-10-01

    Apolipoprotein E is consistently associated with the progression of some common human neurodegenerative diseases, e.g., epilepsy. We hypothesized that genetic variations in the apolipoprotein E gene have implications for susceptibility to, and prognoses in, febrile convulsion, which plays an apparent role in the development of epilepsy. We used the polymerase chain reaction and restriction enzyme digestion to characterize variations of the apolipoprotein E gene. Sixty-nine patients with febrile convulsion (simple/complex) and a corresponding cohort of healthy patients (n = 75) were used. There was no significant difference in genotypic distribution and allelic frequencies of the apolipoprotein E gene between the febrile convulsion and control groups. Comparing subpopulations of the febrile convulsion group (patients with simple and complex febrile convulsion), we noted that no patients with the epsilon3/epsilon4 genotype had complex febrile convulsions. The apolipoprotein E epsilon3/epsilon4 genotype was more frequently seen in the simple febrile than in the complicated febrile convulsion group (9 versus 0 patients, respectively). The data indicate an association with the epsilon3/epsilon4 genotype of the apolipoprotein E gene with a milder phenotype. Although apolipoprotein E4 is not a vulnerability factor regarding febrile convulsions, it seems effective in regard to prognoses.

  5. Apolipoprotein E: the resilience gene.

    PubMed

    James, Lisa M; Engdahl, Brian E; Georgopoulos, Apostolos P

    2017-03-15

    The apolipoprotein E (apoE) gene has been implicated in various conditions, most notably Alzheimer's disease and coronary artery disease. A predisposing role of the apoE4 isoform and a protective role of apoE2 isoform in those diseases have been documented. Here we investigated the role of apoE in resilience to trauma. Three hundred and forty-three US veterans were genotyped for apoE and were assessed for their lifetime trauma exposure (trauma score, T) and severity of posttraumatic stress disorder symptoms (PCL). The ratio PCL/T indicates sensitivity to trauma; hence, its inverse indicates resilience, R, to trauma. We found a significantly higher resilience in participants with apoE genotype containing the E2 allele (E2/2, E2/3) as compared to participants with the E4 allele (E4/4, E4/3). In addition, when the categorical apoE genotype was reexpressed as the number of cysteine residues per apoE mole (CysR/mole), a highly significant positive association was found between resilience and CysR/mole, such that resilience was systematically higher as the number of CysR/mole increased, from zero CysR/mole in E4/4 to four CysR/mole in E2/2. These findings demonstrate the protective role of the CysR/mole apoE in resilience to trauma: the more CysR/mole, the higher the resilience. Thus, they are in accord with other findings pointing to a generally protective role of increasing number of CysR/mole (from E4/4 to E2/2) in other diseases. However, unlike other conditions (e.g., Alzheimer's disease and coronary artery disease), resilience to trauma is not a disease but an adaptive response to trauma. Therefore, the effects of apoE seem to be more pervasive along the CysR/mole continuum, most probably reflecting underlying effects on brain synchronicity and its variability that we have documented previously (Leuthold et al., Exp Brain Res 226:525-536, 2013).

  6. Apolipoprotein E receptor pathways in Alzheimer disease.

    PubMed

    Schmidt, Vanessa; Carlo, Anne-Sophie; Willnow, Thomas E

    2014-01-01

    Alzheimer disease (AD) is the most common neurodegenerative disease affecting millions of patients worldwide. According to the amyloid cascade hypothesis, the formation of neurotoxic oligomers composed of amyloid-β (Aβ) peptides is the main mechanism that causes synaptic dysfunction and, eventually, neuronal cell death in this condition. Intriguingly, apolipoprotein E (apoE), the most important genetic risk factor for sporadic AD, emerges as a key factor that contributes to many aspects of the amyloid cascade including the clearance of Aβ from brain interstitial fluid and the ability of this peptide to form neurotoxic oligomers. Central to the activity of apoE in the healthy and in the diseased brain are apoE receptors that interact with this protein to mediate its multiple cellular and systemic effects. This review describes the molecular interactions that link apoE and its cellular receptors with neuronal viability and function, and how defects in these pathways in the brain promote neurodegeneration. For further resources related to this article, please visit the WIREs website. The authors have declared no conflicts of interest for this article. © 2014 Wiley Periodicals, Inc.

  7. Apolipoprotein E pathology in vascular dementia.

    PubMed

    Rohn, Troy T; Day, Ryan J; Sheffield, Colin B; Rajic, Alexander J; Poon, Wayne W

    2014-01-01

    Vascular dementia (VaD) is the second most common form of dementia and is currently defined as a cerebral vessel vascular disease leading to ischemic episodes. Apolipoprotein E (apoE) gene polymorphism has been proposed as a risk factor for VaD, however, to date there are few documented post-mortem studies on apoE pathology in the VaD brain. To investigate a potential role for the apoE protein, we analyzed seven confirmed cases of VaD by immunohistochemistry utilizing an antibody that specifically detects the amino-terminal fragment of apoE. Application of this antibody, termed N-terminal, apoE cleavage fragment (nApoECF) revealed consistent labeling within neurofibrillary tangles (NFTs), blood vessels, and reactive astrocytes. Labeling occurred in VaD cases that had confirmed APOE genotypes of 3/3, 3/4, and 4/4, with respect to NFTs, staining of the nApoECF co-localized with PHF-1 and was predominantly localized to large, stellate neurons in layer II of the entorhinal cortex. Quantitative analysis indicated that approximately 38.4% of all identified NFTs contained the amino-terminal fragment of apoE. Collectively, these data support a role for the proteolytic cleavage of apoE in the VaD and support previous reports that APOE polymorphism is significantly associated with susceptibility in this disease.

  8. Characterization of mAb dimers reveals predominant dimer forms common in therapeutic mAbs

    PubMed Central

    Plath, Friederike; Ringler, Philippe; Graff-Meyer, Alexandra; Stahlberg, Henning; Lauer, Matthias E.; Rufer, Arne C.; Graewert, Melissa A.; Svergun, Dmitri; Gellermann, Gerald; Finkler, Christof; Stracke, Jan O.; Koulov, Atanas; Schnaible, Volker

    2016-01-01

    ABSTRACT The formation of undesired high molecular weight species such as dimers is an important quality attribute for therapeutic monoclonal antibody formulations. Therefore, the thorough understanding of mAb dimerization and the detailed characterization mAb dimers is of great interest for future pharmaceutical development of therapeutic antibodies. In this work, we focused on the analyses of different mAb dimers regarding size, surface properties, chemical identity, overall structure and localization of possible dimerization sites. Dimer fractions of different mAbs were isolated to a satisfactory purity from bulk material and revealed 2 predominant overall structures, namely elongated and compact dimer forms. The elongated dimers displayed one dimerization site involving the tip of the Fab domain. Depending on the stress applied, these elongated dimers are connected either covalently or non-covalently. In contrast, the compact dimers exhibited non-covalent association. Several interaction points were detected for the compact dimers involving the hinge region or the base of the Fab domain. These results indicate that mAb dimer fractions are rather complex and may contain more than one kind of dimer. Nevertheless, the overall appearance of mAb dimers suggests the existence of 2 predominant dimeric structures, elongated and compact, which are commonly present in preparations of therapeutic mAbs. PMID:27031922

  9. Graded-index optical dimer formed by optical force.

    PubMed

    Akbarzadeh, Alireza; Koschny, Thomas; Kafesaki, Maria; Economou, Eleftherios N; Soukoulis, Costas M

    2016-05-30

    We propose an optical dimer formed from two spherical lenses bound by the pressure that light exerts on matter. With the help of the method of force tracing, we find the required graded-index profiles of the lenses for the existence of the dimer. We study the dynamics of the opto-mechanical interaction of lenses under the illumination of collimated light beams and quantitatively validate the performance of proposed dimer. We also examine the stability of dimer due to the lateral misalignments and we show how restoring forces bring the dimer into lateral equilibrium. The dimer can be employed in various practical applications such as optical manipulation, sensing and imaging.

  10. 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.

  11. 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

  12. Smectic Phase Formed by DNA Dimers

    NASA Astrophysics Data System (ADS)

    Salamonczyk, Miroslaw; Gleeson, James; Jakli, Antal; Sprunt, Samuel; Dhont, Jan; Stiakakis, Emmanuel

    The rapidly expanding bio market is driving the development and characterization of new multifunctional materials. In particular, nucleic acids are under intense study for gene therapy, drug delivery and other bio-safe applications [1,2,3]. DNA is well-known to form a cholesteric nematic liquid crystal in its native form; however, much recent research has focused on self-assembly and mesomorphic behavior in concentrated solutions of short DNA helices [4]. Our work focuses on DNA dimers, consisting of 48 base-pair double-stranded helices connected by a 5 to 20 base flexible single strand, and suspended in a natural buffer. Depending on temperature, concentration and length of the flexible spacer, polarizing optical microscopy and small angle x-ray scattering reveal cholesteric nematic and, remarkably, smectic liquid crystalline phases. A model for smectic phase formation in this system will be presented. 1] J.-L. Lim et al., Int. J. of. Pharm. 490 (2015) 2652] D.-H. Kim et al., Nature Biotech. 23 (2005) 2223] K. Liu et al., Chem. Eur. J. 21 (2015) 48984] M. Nakata et al., Science 318 (2007) 1276 NSF DMR 1307674.

  13. Palmitoylated APP Forms Dimers, Cleaved by BACE1.

    PubMed

    Bhattacharyya, Raja; Fenn, Rebecca H; Barren, Cory; Tanzi, Rudolph E; Kovacs, Dora M

    2016-01-01

    A major rate-limiting step for Aβ generation and deposition in Alzheimer's disease brains is BACE1-mediated cleavage (β-cleavage) of the amyloid precursor protein (APP). We previously reported that APP undergoes palmitoylation at two cysteine residues (Cys186 and Cys187) in the E1-ectodomain. 8-10% of total APP is palmitoylated in vitro and in vivo. Palmitoylated APP (palAPP) shows greater preference for β-cleavage than total APP in detergent resistant lipid rafts. Protein palmitoylation is known to promote protein dimerization. Since dimerization of APP at its E1-ectodomain results in elevated BACE1-mediated cleavage of APP, we have now investigated whether palmitoylation of APP affects its dimerization and whether this leads to elevated β-cleavage of the protein. Here we report that over 90% of palAPP is dimerized while only ~20% of total APP forms dimers. PalAPP-dimers are predominantly cis-oriented while total APP dimerizes in both cis- and trans-orientation. PalAPP forms dimers 4.5-times more efficiently than total APP. Overexpression of the palmitoylating enzymes DHHC7 and DHHC21 that increase palAPP levels and Aβ release, also increased APP dimerization in cells. Conversely, inhibition of APP palmitoylation by pharmacological inhibitors reduced APP-dimerization in coimmunoprecipitation and FLIM/FRET assays. Finally, in vitro BACE1-activity assays demonstrate that palmitoylation-dependent dimerization of APP promotes β-cleavage of APP in lipid-rich detergent resistant cell membranes (DRMs), when compared to total APP. Most importantly, generation of sAPPβ-sAPPβ dimers is dependent on APP-palmitoylation while total sAPPβ generation is not. Since BACE1 shows preference for palAPP dimers over total APP, palAPP dimers may serve as novel targets for effective β-cleavage inhibitors of APP as opposed to BACE1 inhibitors.

  14. Palmitoylated APP Forms Dimers, Cleaved by BACE1

    PubMed Central

    Fenn, Rebecca H.; Barren, Cory; Tanzi, Rudolph E.; Kovacs, Dora M.

    2016-01-01

    A major rate-limiting step for Aβ generation and deposition in Alzheimer’s disease brains is BACE1-mediated cleavage (β-cleavage) of the amyloid precursor protein (APP). We previously reported that APP undergoes palmitoylation at two cysteine residues (Cys186 and Cys187) in the E1-ectodomain. 8–10% of total APP is palmitoylated in vitro and in vivo. Palmitoylated APP (palAPP) shows greater preference for β-cleavage than total APP in detergent resistant lipid rafts. Protein palmitoylation is known to promote protein dimerization. Since dimerization of APP at its E1-ectodomain results in elevated BACE1-mediated cleavage of APP, we have now investigated whether palmitoylation of APP affects its dimerization and whether this leads to elevated β-cleavage of the protein. Here we report that over 90% of palAPP is dimerized while only ~20% of total APP forms dimers. PalAPP-dimers are predominantly cis-oriented while total APP dimerizes in both cis- and trans-orientation. PalAPP forms dimers 4.5-times more efficiently than total APP. Overexpression of the palmitoylating enzymes DHHC7 and DHHC21 that increase palAPP levels and Aβ release, also increased APP dimerization in cells. Conversely, inhibition of APP palmitoylation by pharmacological inhibitors reduced APP-dimerization in coimmunoprecipitation and FLIM/FRET assays. Finally, in vitro BACE1-activity assays demonstrate that palmitoylation-dependent dimerization of APP promotes β-cleavage of APP in lipid-rich detergent resistant cell membranes (DRMs), when compared to total APP. Most importantly, generation of sAPPβ-sAPPβ dimers is dependent on APP-palmitoylation while total sAPPβ generation is not. Since BACE1 shows preference for palAPP dimers over total APP, palAPP dimers may serve as novel targets for effective β-cleavage inhibitors of APP as opposed to BACE1 inhibitors. PMID:27875558

  15. Apolipoprotein E Related Co-Morbidities and Alzheimer's Disease.

    PubMed

    Singhrao, Sim K; Harding, Alice; Chukkapalli, Sasanka; Olsen, Ingar; Kesavalu, Lakshmyya; Crean, StJohn

    2016-01-01

    The primary goal of advancement in clinical services is to provide a health care system that enhances an individual's quality of life. Incidence of diabetes mellitus, cardiovascular disease, and associated dementia coupled with the advancing age of the population, have led to an increase in the worldwide challenge to the healthcare system. In order to overcome these challenges, prior knowledge of common, reliable risk factors and their effectors is essential. Oral health constitutes one such relatively unexplored but indispensable risk factor for aforementioned co-morbidities, in the form of poor oral hygiene and tooth loss during aging. Behavioral traits such as low education, smoking, poor diet, neglect of oral health, lack of exercise, and hypertension are few of the risk factors that are shared commonly among these conditions. In addition, common genetic susceptibility traits such as the apolipoprotein E gene, together with an individual's lifestyle can also influence the development of co-morbidities such as periodontitis, atherosclerosis/stroke, diabetes, and Alzheimer's disease. This review specifically addresses the susceptibility of apolipoprotein E gene allele 4 as the plausible commonality for the etiology of co-morbidities that eventually result from periodontal diseases and ultimately progress to dementia.

  16. Graded-index optical dimer formed by optical force

    DOE PAGES

    Akbarzadeh, Alireza; Koschny, Thomas; Kafesaki, Maria; ...

    2016-05-30

    We propose an optical dimer formed from two spherical lenses bound by the pressure that light exerts on matter. With the help of the method of force tracing, we find the required graded-index profiles of the lenses for the existence of the dimer. We study the dynamics of the opto-mechanical interaction of lenses under the illumination of collimated light beams and quantitatively validate the performance of the proposed dimer. We also examine the stability of the dimer due to the lateral misalignments and we show how restoring forces bring the dimer into lateral equilibrium. The dimer can be employed inmore » various practical applications such as optical manipulation, sensing and imaging.« less

  17. Graded-index optical dimer formed by optical force

    DOE PAGES

    Akbarzadeh, Alireza; Koschny, Thomas; Kafesaki, Maria; ...

    2016-05-30

    We propose an optical dimer formed from two spherical lenses bound by the pressure that light exerts on matter. With the help of the method of force tracing, we find the required graded-index profiles of the lenses for the existence of the dimer. We study the dynamics of the opto-mechanical interaction of lenses under the illumination of collimated light beams and quantitatively validate the performance of the proposed dimer. We also examine the stability of the dimer due to the lateral misalignments and we show how restoring forces bring the dimer into lateral equilibrium. The dimer can be employed inmore » various practical applications such as optical manipulation, sensing and imaging.« less

  18. Graded-index optical dimer formed by optical force

    SciTech Connect

    Akbarzadeh, Alireza; Koschny, Thomas; Kafesaki, Maria; Economou, Eleftherios N.; Soukoulis, Costas M.

    2016-05-30

    We propose an optical dimer formed from two spherical lenses bound by the pressure that light exerts on matter. With the help of the method of force tracing, we find the required graded-index profiles of the lenses for the existence of the dimer. We study the dynamics of the opto-mechanical interaction of lenses under the illumination of collimated light beams and quantitatively validate the performance of the proposed dimer. We also examine the stability of the dimer due to the lateral misalignments and we show how restoring forces bring the dimer into lateral equilibrium. The dimer can be employed in various practical applications such as optical manipulation, sensing and imaging.

  19. Conformation of apolipoprotein E both in free and in lipid-bound form may determine the avidity of triglyceride-rich lipoproteins to the LDL receptor: structural and kinetic study.

    PubMed

    Dergunov, A D; Smirnova, E A; Merched, A; Visvikis, S; Siest, G; Yakushkin, V V; Tsibulsky, V

    2000-02-24

    Slow refolding of human apolipoprotein E (apoE) in solution after guanidine- or cholate-induced denaturation followed by dialysis under controlled conditions was investigated using various spectroscopic properties of fluorescein- and dansyl-labeled apolipoprotein molecules. The results suggest that the last phase(s) of apoE refolding in solution include a slow (several hours at 24 degrees C) interconversion of a self-associated 'open' conformer into a more dense 'closed' conformer. The hydrophobic interactions are primarily responsible for the formation of this more compact apoE structure. To visualize the contribution of apolipoprotein conformation and/or the number of 'active' lipid-bound apoE molecules in the reaction of binding to the low density lipoprotein receptor (LDLr) by solid-phase binding assay, the complexes of human plasma apolipoprotein or recombinant (rec) apoE3 with dipalmitoylphosphatidylcholine (DPPC) or palmitoyloleoylphosphatidylcholine (POPC) varying in size were used. For seven complexes with plasma protein (four DPPC and three POPC complexes), the final phosphatidylcholine (PC)/protein mole ratio ranged from 117 to 279; affinity constant K(a) averaged for both PCs and plotted against this ratio abruptly increased from 3.8 x 10(7) to 3.8 x 10(8) M(-1) with a transition midpoint of 150-180 PC/apoE, mole ratio. Two DPPC complexes with rec protein bind much more efficiently. Complexes with both plasma and rec apoE were able to compete with very low density lipoproteins (VLDL) or low density lipoproteins (LDL) isolated from patients with E3/3 phenotype, for binding to the LDLr. Again, the competition efficiency abruptly increased at the increase in PC content with a transition midpoint of 130 PC/apoE, mole ratio. The transitions observed both in direct and competitive binding assay probably correspond to the abrupt increase in the number of 'active' apoE molecules on the complex surface accompanying the change in the size and/or in the shape of

  20. Apolipoprotein-E genotypes and myasthenia gravis.

    PubMed

    Suhail, Hamid; Soundararajan, Christhunesa C; Vivekanandhan, Subbiah; Singh, Sumit; Behari, Madhuri

    2010-01-01

    Autoimmune myasthenia gravis (MG) is a disorder of neuromuscular junction. Possible role of multiple genes in the development of the MG has been documented. This case-control study, studied the association of apolipoprotein E (Apo-E) alleles with MG. Anti-AChR antibody was measured using radio receptor immunoassay. Apo-E genotypes were analyzed in 120 MG patients and 120 healthy subjects. Comparison between patients with MG and controls showed no significant association with Apo-E allelic variants. However, a significant association of Apo-E4 allele with AChR-antibody positive patients was observed (P = 0.007). Also, among seropositive patients, a significant association was seen between female gender and Apo-E4 allele (P = 0.023). Our results suggest that the presence of Apo-E4 allele might influence seropositive status in patients with MG and seems an associated susceptible factor in female patients.

  1. Apolipoprotein E polymorphism and dendritic shape in hippocampal interneurons.

    PubMed

    Schönheit, Bärbel; Glöckner, Frauke; Ohm, Thomas G

    2007-05-01

    The apolipoprotein E genetic polymorphism exerts a well described influence on Alzheimer's disease (AD) risk, although the pathogenetic mechanism is still not clear. Increasing evidence points to a diminished neuroplasticity in apolipoprotein E varepsilon4-allele carriers. But, alternatively or additionally, developmental differences in dendritic geometry may be associated with the polymorphism. We morphometrically examined the dendritic ramification of CA1 Parvalbumin-positive GABAergic hippocampal neurons (n=571) in matched pairs of aged non-demented individuals with different apolipoprotein E genotype. We chose Parvalbumin-positive interneurons since they lack potentially confounding AD-like cytoskeletal changes. To minimize the risk of transneuronal dendritic changes due to significant deafferentation we focused on non-demented individuals. In this chosen paradigm, neither the disease-associated apolipoprotein E varepsilon4-allele nor the apolipoprotein E varepsilon2-allele had a significant impact on dendritic shape when compared to the most common allelic variant apolipoprotein E varepsilon3/3. At least with respect to the studied cell type, the data suggest that the apolipoprotein E polymorphism does not modulate the original formation of dendrites in vivo, contrary to conclusions drawn from in vitro studies on neurite outgrowth.

  2. 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

  3. Fibulin 5 Forms a Compact Dimer in Physiological Solutions*

    PubMed Central

    Jones, Richard P. O.; Wang, Ming-Chuan; Jowitt, Thomas A.; Ridley, Caroline; Mellody, Kieran T.; Howard, Marjorie; Wang, Tao; Bishop, Paul N.; Lotery, Andrew J.; Kielty, Cay M.; Baldock, Clair; Trump, Dorothy

    2009-01-01

    Fibulin 5 is a 52-kDa calcium-binding epidermal growth factor (cbEGF)-rich extracellular matrix protein that is essential for the formation of elastic tissues. Missense mutations in fibulin 5 cause the elastin disorder cutis laxa and have been associated with age-related macular degeneration, a leading cause of blindness. We investigated the structure, hydrodynamics, and oligomerization of fibulin 5 using small angle x-ray scattering, EM, light scattering, circular dichroism, and sedimentation. Compact structures for the monomer were determined by small angle x-ray scattering and EM, and are supported by close agreement between the theoretical sedimentation of the structures and the experimental sedimentation of the monomer in solution. EM showed that monomers associate around a central cavity to form a dimer. Light scattering and equilibrium sedimentation demonstrated that the equilibrium between the monomer and the dimer is dependent upon NaCl and Ca2+ concentrations and that the dimer is dominant under physiological conditions. The dimerization of fragments containing just the cbEGF domains suggests that intermolecular interactions between cbEGFs cause dimerization of fibulin 5. It is possible that fibulin 5 functions as a dimer during elastinogenesis or that dimerization may provide a method for limiting interactions with binding partners such as tropoelastin. PMID:19617354

  4. 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.

  5. Pharmacogenomic effects of apolipoprotein e on intracerebral hemorrhage.

    PubMed

    James, Michael L; Sullivan, Patrick M; Lascola, Christopher D; Vitek, Michael P; Laskowitz, Daniel T

    2009-02-01

    The purpose of the study was to evaluate the effect of APOE genotype and the feasibility of administering an apolipoprotein E-mimetic therapeutic to modify outcomes in a murine model of intracerebral hemorrhage. Intracerebral hemorrhage was induced via stereotactic injection of 0.1 U Clostridial collagenase into the left basal ganglia of wild-type and apolipoprotein-E targeted-replacement mice, consisting of either homozygous 3/3 or 4/4 genotypes. Animals were randomized to receive either vehicle or apolipoprotein E-mimetic peptide. Outcomes included functional neurological tests (21-point neuroseverity score and Rotorod latency) over the initial 7 days after injury, radiographic and histological hemorrhage size at 3 and 7 days, brain water content for cerebral edema at 24 hours, and quantitative polymerase chain reaction for inflammatory markers at 6, 24, and 48 hours. Apolipoprotein-E targeted-replacement mice consisting of homozygous 3/3 demonstrated superior neuroseverity scores and Rotorod latencies over the first 3 days after intracerebral hemorrhage, decreased cerebral edema at 24 hours, and reduced upregulation of IL-6 and endothelial nitric oxide synthase at 6 hours when compared to their apolipoprotein-E targeted-replacement mice consisting of homozygous 4/4 counterparts. After intravenous administration of 1 mg/kg apolipoprotein E-mimetic peptide, both wild-type and apolipoprotein-E targeted-replacement mice consisting of homozygous 4/4 exhibited improved functional outcomes over 7 days after intracerebral hemorrhage, less edema at 24 hours, and reduced upregulation of IL-6 and endothelial nitric oxide synthase when compared to mice that did not receive the peptide. Our data indicate that APOE genotype influences neurological outcome after intracerebral hemorrhage in a murine model. In particular APOE4 is associated with poor functional outcome and increased cerebral edema. Additionally, this outcome can be modified by the addition of an apolipoprotein E

  6. Secreted CXCL12 (SDF-1) Forms Dimers under Physiologic Conditions

    PubMed Central

    Ray, Paramita; Lewin, Sarah A.; Mihalko, Laura Anne; Lesher-Perez, Sasha Cai; Takayama, Shuichi; Luker, Kathryn E.; Luker, Gary D.

    2015-01-01

    Chemokine CXCL12 signaling through receptors CXCR4 and CXCR7 has essential functions in development and underlies diseases including cancer, atherosclerosis, and autoimmunity. Chemokines may form homodimers that regulate receptor binding and signaling, but previous studies with synthetic CXCL12 have produced conflicting evidence for homodimerization. We used bioluminescence imaging with Gaussia luciferase fusions to investigate dimerization of CXCL12 secreted from mammalian cells. By column chromatography and Gaussia luciferase complementation, we established that CXCL12 was secreted from mammalian cells as both monomers and dimers. Secreted CXCL12 also formed homodimers in the extracellular space. Monomeric CXCL12 preferentially activated CXCR4 signaling through Gαi and AKT, while dimeric CXCL12 more effectively promoted recruitment of β-arrestin 2 to CXCR4 and chemotaxis of CXCR4-expressing breast cancer cells. We also showed that CXCR7 preferentially sequestered monomeric CXCL12 from the extracellular space and had minimal effects on dimeric CXCL12 in cell-based assays and an orthotopic tumor xenograft model of human breast cancer. These studies establish that CXCL12 secreted from mammalian cells forms homodimers under physiologic conditions. Since monomeric and dimeric CXCL12 have distinct effects on cell signaling and function, our results have important implications for ongoing efforts to target CXCL12 pathways for therapy. PMID:22142194

  7. Plasmon excitations in the dimers formed by atom chains

    NASA Astrophysics Data System (ADS)

    Xue, Hong-jie; Hao, Da-peng; Zhang, Ming; Wang, Xiao-mei

    2017-02-01

    Based on the linear response theory in the random-phase approximation and the free-electron gas model, we study the plasmon excitations in the dimers formed by atom chains. With the help of energy absorption spectrum and charge distribution, the evolutions of longitudinal and transverse plasmon, and the effect of the system parameters such as size, atomic separation and electron filling on plasmon are obtained. In addition, the dipole, quadrupole, end and central plasmon are observed.

  8. Homocysteine, Another Risk Factor for Alzheimer Disease, Impairs Apolipoprotein E3 Function*

    PubMed Central

    Minagawa, Hirohisa; Watanabe, Atsushi; Akatsu, Hiroyasu; Adachi, Kayo; Ohtsuka, Chigumi; Terayama, Yasuo; Hosono, Takashi; Takahashi, Satoshi; Wakita, Hideaki; Jung, Cha-Gyun; Komano, Hiroto; Michikawa, Makoto

    2010-01-01

    Apolipoprotein E (apoE) ϵ4 and hyperhomocysteinemia are risk factors for Alzheimer disease (AD). The dimerization of apoE3 by disulfide bonds between cysteine residues enhances apoE3 function to generate HDL. Because homocysteine (Hcy) harbors a thiol group, we examined whether Hcy interferes with the dimerization of apoE3 and thereby impairs apoE3 function. We found that Hcy inhibits the dimerization of apoE3 and reduces apoE3-mediated HDL generation to a level similar to that by apoE4, whereas Hcy does not affect apoE4 function. Western blot analysis of cerebrospinal fluid showed that the ratio of apoE3 dimers was significantly lower in the samples from the patients with hyperhomocysteinemia than in those that from control subjects. Hyperhomocysteinemia induced by subcutaneous injection of Hcy to apoE3 knock-in mice decreased the level of the apoE3 dimer in the brain homogenate. Because apoE-HDL plays a role in amyloid β-protein clearance, these results suggest that two different risk factors, apoE4 and hyperhomocysteinemia, may share a common mechanism that accelerates the pathogenesis of AD in terms of reduced HDL generation. PMID:20889503

  9. 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

  10. Apolipoprotein E and Apolipoprotein E Receptors: Normal Biology and Roles in Alzheimer Disease

    PubMed Central

    Holtzman, David M.; Herz, Joachim; Bu, Guojun

    2012-01-01

    Apolipoprotein E (APOE) genotype is the major genetic risk factor for Alzheimer disease (AD); the ε4 allele increases risk and the ε2 allele is protective. In the central nervous system (CNS), apoE is produced by glial cells, is present in high-density-like lipoproteins, interacts with several receptors that are members of the low-density lipoprotein receptor (LDLR) family, and is a protein that binds to the amyloid-β (Aβ) peptide. There are a variety of mechanisms by which apoE isoform may influence risk for AD. There is substantial evidence that differential effects of apoE isoform on AD risk are influenced by the ability of apoE to affect Aβ aggregation and clearance in the brain. Other mechanisms are also likely to play a role in the ability of apoE to influence CNS function as well as AD, including effects on synaptic plasticity, cell signaling, lipid transport and metabolism, and neuroinflammation. ApoE receptors, including LDLRs, Apoer2, very low-density lipoprotein receptors (VLDLRs), and lipoprotein receptor-related protein 1 (LRP1) appear to influence both the CNS effects of apoE as well as Aβ metabolism and toxicity. Therapeutic strategies based on apoE and apoE receptors may include influencing apoE/Aβ interactions, apoE structure, apoE lipidation, LDLR receptor family member function, and signaling. Understanding the normal and disease-related biology connecting apoE, apoE receptors, and AD is likely to provide novel insights into AD pathogenesis and treatment. PMID:22393530

  11. Plasma apolipoprotein E and severity of suicidal behaviour.

    PubMed

    Asellus, Peter; Nordström, Peter; Nordström, Anna-Lena; Jokinen, Jussi

    2016-01-15

    There is evidence for association between low cholesterol levels and suicidal behaviour. Since apolipoprotein E (ApoE) is involved in the cholesterol metabolism in both the periphery and in the central nervous system; it may be of particular interest in the neurobiology of suicidal behaviour. Furthermore, hypothalamic-pituitary-adrenal (HPA) axis function, one of the main biological systems implicated in both suicidal behaviour and early-life adversity, affect ApoE levels. Very few studies have assessed plasma ApoE in relation to suicidal behaviour. The purpose of this study was to investigate levels of ApoE in plasma in relation to the severity of suicidal behaviour and life-time adversity in the form of exposure to interpersonal violence in suicide attempters. A total of 100 suicide attempters (67 women and 33 men) were enroled in the study. Information on earlier suicide attempts and age at onset of suicidal behaviour was gathered using the Karolinska Suicide History Interview. The Karolinska Interpersonal Violence Scale was used to assess exposure to interpersonal violence. Plasma ApoE was measured by immunonephelometry according to accredited routines. Patients with at least one earlier suicide attempt had significantly higher ApoE levels compared to suicide attempters debuting with suicidal behaviour at inclusion in the study. A higher number of earlier suicide attempts was significantly correlated with higher plasma ApoE levels. Age at onset was significantly negatively correlated with ApoE after adjusting for age. ApoE showed a significant positive correlation with exposure to interpersonal violence as a child in male suicide attempters. Our findings indicate that ApoE may be related to stress and trauma and the temporal severity of suicidal behaviour.

  12. Apolipoprotein E and its role in aging and survival.

    PubMed

    Bonomini, Francesca; Filippini, Francesca; Hayek, Tony; Aviram, Michael; Keidar, Shlomo; Rodella, Luigi F; Coleman, Raymond; Rezzani, Rita

    2010-02-01

    The study of biological aging has seen spectacular progress in the last decade and markers are increasingly employed for understanding physiological processes that change with age. Recently, it has been demonstrated that apolipoprotein E (apoE) has a major impact on longevity, but its mechanisms are still not fully understood. ApoE-deficient (E(o)) mice have proved to be a very popular model for studying spontaneous hypercholesterolemia and the subsequent development of atherosclerotic lesions, but only limited data are available with regard to aging and aging changes. We used this murine model to better characterize the involvement of apoE in aging and to evaluate its role in the maintenance of normal organ morphology. Our results show that E(0) mice at different ages (6, 12, 20 weeks old) developed age-dependent morphological and biochemical alterations, including fibrosis (newly formed collagen), pro-inflammatory cytokine (IL-6 and iNOS), lipofuscin accumulation, and decrease of antioxidant enzymes (superoxide dismutase and catalase) in several organs (kidney, liver and heart). It is significant that the observed degenerative findings in E(0) mice at different ages (6, 12, 20 weeks old) were not identified in control mice (C57BL), at 6, 12 and 20 weeks of age. Consequently, since these mice showed enzymatic and structural alterations, normally linked to the age, such as increase of lipofuscin, pro-inflammatory cytokines and decrease of antioxidant enzymes, we can conclude that apoE is a useful player in studies of longevity and age-related diseases, such as inflammatory status and atherosclerosis that are known risk factors for functional decline and early mortality. Moreover, it is possible that apoE may also play a role in other pathological conditions including, for example, cancer, rheumatoid arthritis and macular degeneration.

  13. Introduction of human apolipoprotein E4 "domain interaction" into mouse apolipoprotein E.

    PubMed

    Raffai, R L; Dong, L M; Farese, R V; Weisgraber, K H

    2001-09-25

    Human apolipoprotein E4 (apoE4) binds preferentially to lower density lipoproteins, including very low density lipoproteins, and is associated with increased risk of atherosclerosis and neurodegenerative disorders, including Alzheimer's disease. This binding preference is the result of the presence of Arg-112, which causes Arg-61 in the amino-terminal domain to interact with Glu-255 in the carboxyl-terminal domain. ApoE2 and apoE3, which have Cys-112, bind preferentially to high density lipoproteins (HDL) and do not display apoE4 domain interaction. Mouse apoE, like apoE4, contains the equivalent of Arg-112 and Glu-255, but lacks the critical Arg-61 equivalent (it contains Thr-61). Thus, mouse apoE does not display apoE4 domain interaction and, as a result, behaves like human apoE3, including preferential binding to HDL. To assess the potential role of apoE4 domain interaction in atherosclerosis and neurodegeneration, we sought to introduce apoE4 domain interaction into mouse apoE. Replacing Thr-61 in mouse apoE with arginine converted the binding preference from HDL to very low density lipoproteins in vitro, suggesting that apoE4 domain interaction could be introduced into mouse apoE in vivo. Using gene targeting in embryonic stem cells, we created mice expressing Arg-61 apoE. Heterozygous Arg-61/wild-type apoE mice displayed two phenotypes found in human apoE4/E3 heterozygotes: preferential binding to lower density lipoproteins and reduced abundance of Arg-61 apoE in the plasma, reflecting its more rapid catabolism. These findings demonstrate the successful introduction of apoE4 domain interaction into mouse apoE in vivo. The Arg-61 apoE mouse model will allow the effects of apoE4 domain interaction in lipoprotein metabolism, atherosclerosis, and neurodegeneration to be determined.

  14. Full-length apolipoprotein E protects against the neurotoxicity of an apoE-related peptide

    PubMed Central

    Crutcher, K.A.; Lilley, H.N.; Anthony, S. R.; Zhou, W.; Narayanaswami, V.

    2009-01-01

    Apolipoprotein E was found to protect against the neurotoxic effects of a dimeric peptide derived from the receptor-binding region of this protein (residues 141–149). Both apoE3 and apoE4 conferred protection but the major N-terminal fragment of each isoform did not. Nor was significant protection provided by bovine serum albumin or apoA-I. Full-length apoE3 and apoE4 also inhibited the uptake of a fluorescent-labeled derivative of the peptide, suggesting that the mechanism of inhibition might involve competition for cell surface receptors/proteoglycans that mediate endocytosis and/or signaling pathways. These results might bear on the question of the role of apoE in neuronal degeneration, such as occurs in Alzheimer’s disease where apoE4 confers a significantly greater risk of pathology. PMID:19836363

  15. Effect of apolipoprotein E genotype and diet on apolipoprotein E lipidation and amyloid peptides: randomized clinical trial.

    PubMed

    Hanson, Angela J; Bayer-Carter, Jennifer L; Green, Pattie S; Montine, Thomas J; Wilkinson, Charles W; Baker, Laura D; Watson, G Stennis; Bonner, Laura M; Callaghan, Maureen; Leverenz, James B; Tsai, Elaine; Postupna, Nadia; Zhang, Jing; Lampe, Johanna; Craft, Suzanne

    2013-08-01

    Sporadic Alzheimer disease (AD) is caused in part by decreased clearance of the β-amyloid (Aβ) peptide breakdown products. Lipid-depleted (LD) apolipoproteins are less effective at binding and clearing Aβ, and LD Aβ peptides are more toxic to neurons. However, not much is known about the lipid states of these proteins in human cerebrospinal fluid. To characterize the lipidation states of Aβ peptides and apolipoprotein E in the cerebrospinal fluid in adults with respect to cognitive diagnosis and APOE ε4 allele carrier status and after a dietary intervention. Randomized clinical trial. Veterans Affairs Medical Center clinical research unit. Twenty older adults with normal cognition (mean [SD] age, 69 [7] years) and 27 with amnestic mild cognitive impairment (67 [6] years). Randomization to a diet high in saturated fat content and with a high glycemic index (High diet; 45% of energy from fat [>25% saturated fat], 35%-40% from carbohydrates with a mean glycemic index >70, and 15%-20% from protein) or a diet low in saturated fat content and with a low glycemic index (Low diet; 25% of energy from fat [<7% saturated fat], 55%-60% from carbohydrates with a mean glycemic index <55, and 15%-20% from protein). Lipid-depleted Aβ42 and Aβ40 and apolipoprotein E in cerebrospinal fluid. Baseline levels of LD Aβ were greater for adults with mild cognitive impairment compared with adults with normal cognition (LD Aβ42, P = .05; LD Aβ40, P = .01). These findings were magnified in adults with mild cognitive impairment and the ε4 allele, who had higher LD apolipoprotein E levels irrespective of cognitive diagnosis (P < .001). The Low diet tended to decrease LD Aβ levels, whereas the High diet increased these fractions (LD Aβ42, P = .01; LD Aβ40, P = .15). Changes in LD Aβ levels with the Low diet negatively correlated with changes in cerebrospinal fluid levels of insulin (LD Aβ42 and insulin, r = -0.68 [P = .01]; LD Aβ40 and insulin, r = -0.78 [P = .002]). The

  16. Motor and cognitive deficits in apolipoprotein E-deficient mice after closed head injury.

    PubMed

    Chen, Y; Lomnitski, L; Michaelson, D M; Shohami, E

    1997-10-01

    Previous studies suggest that traumatic brain injury is associated with increased risk factor for developing Alzheimer's disease. Furthermore, the extent of the risk seems to be most pronounced in Alzheimer's disease patients who carry the epsilon4 allele of apolipoprotein E, suggesting a connection between susceptibility to head trauma and the apolipoprotein E genotype. Apolipoprotein E-deficient mice provide a useful model for investigating the role of this lipoprotein in neuronal maintenance and repair. In the present study apolipoprotein E-deficient mice and a closed head injury experimental paradigm were used to examine the role of apolipoprotein E in brain susceptibility to head trauma and in neuronal repair. Apolipoprotein E-deficient mice were assessed up to 40 days after closed head injury for neurological and cognitive functions, as well as for histopathological changes in the hippocampus. A neurological severity score used for clinical assessment revealed more severe motor and behavioural deficits in the apolipoprotein E-deficient mice than in the controls, the impairment persisting for at least 40 days after injury. Performance in the Morris water maze, which tests spatial memory, showed a marked learning deficit of the apolipoprotein E-deficient mice when compared with injured controls, which was apparent for at least 40 days. At this time, histopathological examination revealed overt neuronal cell death bilaterally in the hippocampus of the injured apolipoprotein E-deficient mice. The finding that apolipoprotein E-deficient mice exhibit an impaired ability to recover from closed head injury suggests that apolipoprotein E plays an important role in neuronal repair following injury and highlights the applicability of this mouse model to the study of the cellular and molecular mechanisms involved.

  17. ApolipoproteinE mimetic peptides improve outcome after focal ischemia.

    PubMed

    Wang, Haichen; Anderson, Lauren G; Lascola, Christopher D; James, Michael L; Venkatraman, Talaignair N; Bennett, Ellen R; Acheson, Shawn K; Vitek, Michael P; Laskowitz, Daniel T

    2013-03-01

    Growing clinical evidence implicates isoform-specific effects of apolipoprotein E (apoE) in reducing neuroinflammation and mediating adaptive responses following ischemic and traumatic brain injury. However, the intact apoE holoprotein does not cross the blood-brain barrier and thus has limited therapeutic potential. We have created a small peptide, COG1410 (acetyl-AS-Aib-LRKL-Aib-KRLL-amide), derived from the apoE receptor-binding region. COG1410 retains the anti-inflammatory and neuroprotective biological properties of the intact holoprotein and penetrates the blood-brain barrier. In the current study, we utilized a murine model of transient focal cerebral ischemia and reperfusion to demonstrate that intravenous (IV) administration of COG1410 reduces infarct volume and radiographic progression of infarct, and improves functional outcome as assessed by rotarod when delivered up to 4h after ischemia onset. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Apolipoprotein E epsilon4 allele and neurobehavioral status after on-pump coronary artery bypass grafting.

    PubMed

    Askar, Fatma Zekiye; Cetin, Hasan Yurday; Kumral, Emre; Cetin, Ozgul; Acarer, Ahmet; Kosova, Buket; Yagdi, Tahir

    2005-01-01

    Abstract Background and Aim: The presence of apolipoprotein E epsilon4 allele is being considered as a risk factor for cognitive decline after cardiac surgery. We sought the effect of apolipoprotein E epsilon4 allele on neurobehavioral status after on-pump coronary artery bypass grafting. Prior to the operation, neurologic examination and neurobehavioral cognitive status test (COGNISTAT) were performed. Both procedures were repeated on the day of discharge and 3 months after surgery. Apolipoprotein E epsilon4 allele positive and apolipoprotein E epsilon4 allele negative patients' performance on COGNISTAT were compared. There was no statistically significant demographic and operative data difference between two groups. No neurological impairment was observed on examinations. There was no statistically significant neurocognitive decline difference between two groups' postoperative performances. It seems that apolipoprotein E epsilon4 allele may not affect neurobehavioral status in the intermediate period after on-pump coronary artery bypass grafting.

  19. Subunit interface mutants of rabbit muscle aldolase form active dimers.

    PubMed Central

    Beernink, P. T.; Tolan, D. R.

    1994-01-01

    We report the construction of subunit interface mutants of rabbit muscle aldolase A with altered quaternary structure. A mutation has been described that causes nonspherocytic hemolytic anemia and produces a thermolabile aldolase (Kishi H et al., 1987, Proc Natl Acad Sci USA 84:8623-8627). The disease arises from substitution of Gly for Asp-128, a residue at the subunit interface of human aldolase A. To elucidate the role of this residue in the highly homologous rabbit aldolase A, site-directed mutagenesis is used to replace Asp-128 with Gly, Ala, Asn, Gln, or Val. Rabbit aldolase D128G purified from Escherichia coli is found to be similar to human D128G by kinetic analysis, CD, and thermal inactivation assays. All of the mutant rabbit aldolases are similar to the wild-type rabbit enzyme in secondary structure and kinetic properties. In contrast, whereas the wild-type enzyme is a tetramer, chemical crosslinking and gel filtration indicate that a new dimeric species exists for the mutants. In sedimentation velocity experiments, the mutant enzymes as mixtures of dimer and tetramer at 4 degrees C. Sedimentation at 20 degrees C shows that the mutant enzymes are > 99.5% dimeric and, in the presence of substrate, that the dimeric species is active. Differential scanning calorimetry demonstrates that Tm values of the mutant enzymes are decreased by 12 degrees C compared to wild-type enzyme. The results indicate that Asp-128 is important for interface stability and suggest that 1 role of the quaternary structure of aldolase is to provide thermostability. PMID:7833800

  20. Helical arrays of U-shaped ATP synthase dimers form tubular cristae in ciliate mitochondria

    PubMed Central

    Mühleip, Alexander W.; Joos, Friederike; Wigge, Christoph; Frangakis, Achilleas S.; Kühlbrandt, Werner; Davies, Karen M.

    2016-01-01

    F1Fo-ATP synthases are universal energy-converting membrane protein complexes that synthesize ATP from ADP and inorganic phosphate. In mitochondria of yeast and mammals, the ATP synthase forms V-shaped dimers, which assemble into rows along the highly curved ridges of lamellar cristae. Using electron cryotomography and subtomogram averaging, we have determined the in situ structure and organization of the mitochondrial ATP synthase dimer of the ciliate Paramecium tetraurelia. The ATP synthase forms U-shaped dimers with parallel monomers. Each complex has a prominent intracrista domain, which links the c-ring of one monomer to the peripheral stalk of the other. Close interaction of intracrista domains in adjacent dimers results in the formation of helical ATP synthase dimer arrays, which differ from the loose dimer rows in all other organisms observed so far. The parameters of the helical arrays match those of the cristae tubes, suggesting the unique features of the P. tetraurelia ATP synthase are directly responsible for generating the helical tubular cristae. We conclude that despite major structural differences between ATP synthase dimers of ciliates and other eukaryotes, the formation of ATP synthase dimer rows is a universal feature of mitochondria and a fundamental determinant of cristae morphology. PMID:27402755

  1. Cognitive function after major noncardiac surgery, apolipoprotein E4 genotype, and biomarkers of brain injury.

    PubMed

    McDonagh, David L; Mathew, Joseph P; White, Willam D; Phillips-Bute, Barbara; Laskowitz, Daniel T; Podgoreanu, Mihai V; Newman, Mark F

    2010-04-01

    Postoperative cognitive dysfunction (POCD) is a significant cause of morbidity after noncardiac surgery. Identified risk factors are largely limited to demographic characteristics. We hypothesized that POCD was associated with apolipoprotein E4 (APOE4) genotype and plasma biomarkers of brain injury and inflammation. Three hundred ninety-four patients older than 55 yr undergoing major elective noncardiac surgery were enrolled in this prospective observational study. Apolipoprotein E genotyping was performed at baseline. Plasma was collected at baseline and end of surgery and at 4.5, 24, and 48-h postoperatively. Six protein biomarkers were assayed (B-type natriuretic peptide, C-reactive protein, D-dimer, matrix metalloproteinase-9, neuron-specific enolase, and S-100B). Neurocognitive testing was conducted at baseline and at 6 weeks and 1 yr after surgery; scores were subjected to factor analysis. The association of APOE4 and biomarkers with POCD was tested using multivariable regression modeling. Three hundred fifty patients (89%) completed 6-week neurocognitive testing. POCD occurred in 54.3% of participants at 6 weeks and 46.1% at 1 yr. There was no difference in POCD between patients with or without the APOE4 allele (56.6 vs. 52.6%; P = 0.58). The continuous cognitive change score (mean +/- SD) was similar between groups (APOE4: 0.05 +/- 0.27 vs. non-APOE4: 0.07 +/- 0.28; P = 0.53). Two hundred ninety-one subjects (74%) completed testing at 1 yr. POCD occurred in 45.9% of APOE4 subjects versus 46.3% of non-APOE4 subjects (P = 0.95). The cognitive score was again similar (APOE4: 0.08 +/- 0.27 vs. non-APOE4: 0.05 +/- 0.25; P = 0.39). Biomarker levels were not associated with APOE4 genotype or cognition at 6 weeks or 1 yr. Cognitive decline after major noncardiac surgery is not associated with APOE4 genotype or plasma biomarker levels.

  2. Cognitive Function after Major Noncardiac Surgery, Apolipoprotein E4 Genotype, and Biomarkers of Brain Injury

    PubMed Central

    McDonagh, David L.; Mathew, Joseph P.; White, Willam D.; Phillips-Bute, Barbara; Laskowitz, Daniel T.; Podgoreanu, Mihai V.; Newman, Mark F.

    2010-01-01

    Background Postoperative cognitive dysfunction (POCD) is a significant cause of morbidity after noncardiac surgery. Identified risk factors are largely limited to demographic characteristics. We hypothesized that POCD was associated with Apolipoprotein E4 (APOE4) genotype and plasma biomarkers of brain injury and inflammation. Methods 394 patients over age 55 undergoing major elective noncardiac surgery were enrolled in this prospective observational study. Apolipoprotein E genotyping was performed at baseline. Plasma was collected at baseline, end of surgery, 4.5, 24, and 48-h postoperatively. Six protein biomarkers were assayed (B-type natriuretic peptide, C-reactive protein, D-dimer, matrix metalloproteinase-9, neuron specific enolase, S-100B). Neurocognitive testing was conducted at baseline, 6 weeks, and 1 yr after surgery; scores were subjected to factor analysis. The association of APOE4 and biomarkers with POCD was tested using multivariable regression modeling. Results 350 patients (89%) completed 6-week neurocognitive testing. POCD occurred in 54.3% of participants at 6 weeks and 46.1% at 1 yr. There was no difference in POCD between patients with or without the APOE4 allele (56.6 vs. 52.6%; p = 0.58). The continuous cognitive change score (mean ± SD) was similar between groups (APOE4: 0.05 ± 0.27 vs. non-APOE4: 0.07 ± 0.28; p = 0.53). 291 subjects (74%) completed testing at 1 yr. POCD occurred in 45.9% of APOE4 subjects versus 46.3% of non-APOE4 subjects (p = 0.95). The cognitive score was again similar (APOE4: 0.08 ± 0.27 vs. non-APOE4: 0.05 ± 0.25; p = 0.39). Biomarker levels were not associated with APOE4 genotype or cognition at 6 weeks or 1 yr. Conclusion Cognitive decline after major noncardiac surgery is not associated with APOE4 genotype or plasma biomarker levels. PMID:20216394

  3. 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

  4. Apolipoprotein E and Alzheimer disease: risk, mechanisms and therapy.

    PubMed

    Liu, Chia-Chen; Liu, Chia-Chan; Kanekiyo, Takahisa; Xu, Huaxi; Bu, Guojun

    2013-02-01

    Apolipoprotein E (Apo-E) is a major cholesterol carrier that supports lipid transport and injury repair in the brain. APOE polymorphic alleles are the main genetic determinants of Alzheimer disease (AD) risk: individuals carrying the ε4 allele are at increased risk of AD compared with those carrying the more common ε3 allele, whereas the ε2 allele decreases risk. Presence of the APOE ε4 allele is also associated with increased risk of cerebral amyloid angiopathy and age-related cognitive decline during normal ageing. Apo-E-lipoproteins bind to several cell-surface receptors to deliver lipids, and also to hydrophobic amyloid-β (Aβ) peptide, which is thought to initiate toxic events that lead to synaptic dysfunction and neurodegeneration in AD. Apo-E isoforms differentially regulate Aβ aggregation and clearance in the brain, and have distinct functions in regulating brain lipid transport, glucose metabolism, neuronal signalling, neuroinflammation, and mitochondrial function. In this Review, we describe current knowledge on Apo-E in the CNS, with a particular emphasis on the clinical and pathological features associated with carriers of different Apo-E isoforms. We also discuss Aβ-dependent and Aβ-independent mechanisms that link Apo-E4 status with AD risk, and consider how to design effective strategies for AD therapy by targeting Apo-E.

  5. Role for apolipoprotein E in neurodegeneration and mercury intoxication.

    PubMed

    Arrifano, Gabriela de Paula Fonseca; de Oliveira, Marcus Augusto; Souza-Monteiro, Jose Rogerio; Paraense, Ricardo Oliveira; Ribeiro-Dos-Santos, Andrea; Vieira, Jose Richardo Dos Santos; Silva, Artur Luis da Costa; Macchi, Barbarella de Matos; do Nascimento, Jose Luiz Martins; Burbano, Rommel Mario Rodriguez; Crespo-Lopez, Maria Elena

    2018-01-01

    Mercury intoxication is a serious public health problem and a worldwide concern. The Minamata Convention on Mercury has been signed by 128 countries and endorsed by the World Health Organization with the recommendation of promoting the management of epidemiological information. The Central Nervous System is the main target organ for mercury. Symptoms of intoxication include altered motor coordination, visual and tactile dysfunction and paralysis, caused by neurodegeneration with a key role for oxidative damage. Recently, some studies have demonstrated a correlation between mercury intoxication and isoforms of apolipoprotein E (ApoE). In this review, epidemiological data and hypotheses about the possible molecular mechanisms underlying the association between ApoE and mercury intoxication are assessed. Based on the evidence and the neuropathological changes that the presence of ApoE4 and mercury neurotoxicity have in common, we propose a convergent action of both factors. ApoE4 seems to potentiate the damage caused by mercury. Increased knowledge of this interaction using epidemiological and pre-clinical studies is essential to improve prevention strategies to adequately manage intoxicated patients.

  6. Apolipoprotein E and Alzheimer disease: risk, mechanisms, and therapy

    PubMed Central

    Liu, Chia-Chen; Kanekiyo, Takahisa; Xu, Huaxi; Bu, Guojun

    2013-01-01

    Apolipoprotein E (ApoE) is a major cholesterol carrier that supports lipid transport and injury repair in the brain. APOE polymorphic alleles are the main genetic determinants of Alzheimer disease (AD) risk: individuals carrying the ε4 allele are at increased risk of AD compared with those carrying the more common ε3 allele, whereas the ε2 allele decreases risk. Presence of the APOE ε4 allele is also associated with increased risk for cerebral amyloid angiopathy and age-related cognitive decline during normal ageing. ApoE–lipoproteins bind to several cell-surface receptors to deliver lipids and also to hydrophobic amyloid-β (Aβ) peptide, which is thought to initiate toxic events that lead to synaptic dysfunction and neurodegeneration in AD. ApoE isoforms differentially regulate Aβ aggregation and clearance in the brain, and have distinct functions in regulating brain lipid transport, glucose metabolism, neuronal signalling, neuroinflammation, and mitochondrial function. In this Review, we describe current knowledge on ApoE in the CNS, with a particular emphasis on the clinical and pathological features associated with carriers of different ApoE isoforms. We also discuss Aβ-dependent and Aβ-independent mechanisms that link ApoE4 status with AD risk, and consider how to design effective strategies for AD therapy by targeting ApoE. PMID:23296339

  7. Prenatal mercury exposure, neurodevelopment and apolipoprotein E genetic polymorphism.

    PubMed

    Snoj Tratnik, Janja; Falnoga, Ingrid; Trdin, Ajda; Mazej, Darja; Fajon, Vesna; Miklavčič, Ana; Kobal, Alfred B; Osredkar, Joško; Sešek Briški, Alenka; Krsnik, Mladen; Neubauer, David; Kodrič, Jana; Stropnik, Staša; Gosar, David; Lešnik Musek, Petra; Marc, Janja; Jurkovič Mlakar, Simona; Petrović, Oleg; Vlašić-Cicvarić, Inge; Prpić, Igor; Milardović, Ana; Radić Nišević, Jelena; Vuković, Danijela; Fišić, Elizabeta; Špirić, Zdravko; Horvat, Milena

    2017-01-01

    The aim of the present study was to evaluate the association between prenatal exposure to mercury (Hg) and neurodevelopment of the child, taking into account genetic polymorphism of apolipoprotein E (Apoe) and other relevant confounders. Six hundred and one mother-child pairs were recruited from the central Slovenia region and 243 from Rijeka, on the Croatian coast of the northern Adriatic. The total Hg in cord blood, Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) assessment at 18 months of age and Apoe genotyping was performed on 361 children; 237 of them were from Slovenia and 124 from Croatia. The results showed negative association between low-to-moderate Hg exposure in children with normal neurodevelopmental outcome and cognitive and fine motor scores at 18 months of age as assessed by Bayley III. The Hg-related decrease in cognitive score was observed only in children carrying at least one Apoe ε4 allele, while the decrease in fine motor scores was independent of the Apoe genotype. Adjusting for selenium (Se) and lead (Pb) levels, a positive association between Se and the language score and a negative association between Pb and the motor score was observed, but not in the subgroup of children carrying the ε4 allele.

  8. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. 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

    2016-09-20

    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.

  10. Cerebrovascular effects of apolipoprotein E: implications for Alzheimer disease.

    PubMed

    Zlokovic, Berislav V

    2013-04-01

    Human apolipoprotein E (apoE) has 3 isoforms: apoE2, apoE3, and apoE4. APOE4 is a major genetic risk factor for Alzheimer disease and is associated with dementia in Down syndrome and poor neurological outcome after traumatic brain injury, cerebral hemorrhage, and other neuropathological disorders. While apoE4 can induce neuropathology by participating in various cellular and molecular pathways, herein I review data supporting the hypothesis that apoE4 has direct toxic effects on the cerebrovascular system that in turn can lead to secondary neuronal dysfunction and degeneration as well as accumulation of neurotoxins in brain such as β-amyloid (Aβ) in Alzheimer disease. I review Aβ-independent cerebrovascular effects of apoE, particularly activation of a proinflammatory cyclophilin A-mediated pathway in brain vascular pericytes by apoE4 that has recently been shown to lead to a loss of cerebrovascular integrity and blood-brain barrier breakdown causing neuronal injury. I also review Aβ-dependent cerebrovascular effects of apoE such as faulty Aβ clearance from brain to circulation by apoE4. Finally, I discuss isoform-specific interactions of apoE with low-density lipoprotein receptor-related protein 1 on brain vascular cells (ie, endothelial cells, pericytes), which play an important role in Aβ-independent and Aβ-dependent effects of apoE on cerebral vasculature.

  11. Digoxin reduces atherosclerosis in apolipoprotein E-deficient mice.

    PubMed

    Shi, Huairui; Mao, Xiaobo; Zhong, Yucheng; Liu, Yuzhou; Zhao, Xiaoqi; Yu, Kunwu; Zhu, Ruirui; Wei, Yuzhen; Zhu, Jianghao; Sun, Haitao; Mao, Yi; Zeng, Qiutang

    2016-05-01

    Numerous in vitro studies have suggested that digoxin suppresses inflammation and alters lipid metabolism. However, the effect of dioxin on atherosclerosis is poorly understood. The present study was conducted to determine whether digoxin affects the development of atherosclerosis in a murine model of atherosclerotic disease. Apolipoprotein E-deficient mice maintained on a Western-type diet were administered PBS (control), low-dose digoxin (1 mg · kg(-1) · day(-1)) or high-dose digoxin (2 mg · kg(-1) · day(-1)) via i.p. injection for 12 weeks. Digoxin dose-dependently reduced atherosclerotic lesion formation and plasma lipid levels (reductions of 41% in total cholesterol, 54% in triglycerides and 20% in low-density lipoprotein cholesterol in the high-dose digoxin-treated group). Moreover, treatment with digoxin markedly attenuated IL-17A expression and IL-17A-related inflammatory responses and increased the abundance of regulatory T cells (Tregs). Our data demonstrate that digoxin acts as a specific antagonist of retinoid-related orphan receptor-γ to decrease atherosclerosis by suppressing lipid levels and IL-17A-related inflammatory responses. © 2016 The British Pharmacological Society.

  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. Alzheimer's disease, apolipoprotein E and hormone replacement therapy.

    PubMed

    Depypere, H; Vierin, A; Weyers, S; Sieben, A

    2016-12-01

    Alzheimer's disease is the most frequent cause of dementia in older patients. The prevalence is higher in women than in men. This may be the result of both the higher life expectancy of women and the loss of neuroprotective estrogen after menopause. Earlier age at menopause (spontaneous or surgical) is associated with an enhanced risk of developing Alzheimer's disease. Therefore, it is postulated that estrogen could be protective against it. If so, increasing exposure to estrogen through the use of postmenopausal hormone replacement could also be protective against Alzheimer's disease. The results of the clinical studies that have examined this hypothesis are inconclusive, however. One explanation for this is that estrogen treatment is protective only if it is initiated in the years immediately after menopause. Another possibility is that the neuroprotective effects of estrogen are negated by a particular genotype of apolipoprotein E. This protein plays an important role in cholesterol transport to the neurons. Studies that have examined the link between estrogen replacement therapy, Alzheimer's disease and the E4 allele of ApoE are inconclusive. This article reviews the literature on the influence of hormone replacement therapy on the incidence and progression of Alzheimer's disease.

  14. Apolipoprotein E receptor 2 is involved in the thrombotic complications in a murine model of the antiphospholipid syndrome.

    PubMed

    Romay-Penabad, Zurina; Aguilar-Valenzuela, Renan; Urbanus, Rolf T; Derksen, Ronald H W M; Pennings, Maarten T T; Papalardo, Elizabeth; Shilagard, Tuya; Vargas, Gracie; Hwang, Yong; de Groot, Philip G; Pierangeli, Silvia S

    2011-01-27

    Antiphospholipid (aPL)/anti-β(2) glycoprotein I (anti-β(2)GPI) antibodies stimulates tissue factor (TF) expression within vasculature and in blood cells, thereby leading to increased thrombosis. Several cellular receptors have been proposed to mediate these effects, but no convincing evidence for the involvement of a specific one has been provided. We investigated the role of Apolipoprotein E receptor 2 (ApoER2') on the pathogenic effects of a patient-derived polyclonal aPL IgG preparation (IgG-APS), a murine anti-β(2)GPI monoclonal antibody (E7) and of a constructed dimeric β(2)GPI I (dimer), which in vitro mimics β(2)GPI-antibody immune complexes, using an animal model of thrombosis, and ApoER2-deficient (-/-) mice. In wild type mice, IgG-APS, E7 and the dimer increased thrombus formation, carotid artery TF activity as well as peritoneal macrophage TF activity/expression. Those pathogenic effects were significantly reduced in ApoER2 (-/-) mice. In addition, those effects induced by the IgG-APS, by E7 and by the dimer were inhibited by treatment of wild-type mice with soluble binding domain 1 of ApoER2 (sBD1). Altogether these data show that ApoER2 is involved in pathogenesis of antiphospholipids antibodies.

  15. Apolipoprotein E receptor 2 is involved in the thrombotic complications in a murine model of the antiphospholipid syndrome

    PubMed Central

    Romay-Penabad, Zurina; Aguilar-Valenzuela, Renan; Urbanus, Rolf T.; Derksen, Ronald H. W. M.; Pennings, Maarten T. T.; Papalardo, Elizabeth; Shilagard, Tuya; Vargas, Gracie; Hwang, Yong; de Groot, Philip G.

    2011-01-01

    Antiphospholipid (aPL)/anti-β2 glycoprotein I (anti-β2GPI) antibodies stimulates tissue factor (TF) expression within vasculature and in blood cells, thereby leading to increased thrombosis. Several cellular receptors have been proposed to mediate these effects, but no convincing evidence for the involvement of a specific one has been provided. We investigated the role of Apolipoprotein E receptor 2 (ApoER2′) on the pathogenic effects of a patient-derived polyclonal aPL IgG preparation (IgG-APS), a murine anti-β2GPI monoclonal antibody (E7) and of a constructed dimeric β2GPI I (dimer), which in vitro mimics β2GPI-antibody immune complexes, using an animal model of thrombosis, and ApoER2-deficient (−/−) mice. In wild type mice, IgG-APS, E7 and the dimer increased thrombus formation, carotid artery TF activity as well as peritoneal macrophage TF activity/expression. Those pathogenic effects were significantly reduced in ApoER2 (−/−) mice. In addition, those effects induced by the IgG-APS, by E7 and by the dimer were inhibited by treatment of wild-type mice with soluble binding domain 1 of ApoER2 (sBD1). Altogether these data show that ApoER2 is involved in pathogenesis of antiphospholipids antibodies. PMID:21119114

  16. Cerebral lipid deposition in aged apolipoprotein-E-deficient mice.

    PubMed

    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

    1997-11-01

    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.

  17. 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

  18. Thyroid hormones upregulate apolipoprotein E gene expression in astrocytes.

    PubMed

    Roman, Corina; Fuior, Elena V; Trusca, Violeta G; Kardassis, Dimitris; Simionescu, Maya; Gafencu, Anca V

    Apolipoprotein E (apoE), a protein mainly involved in lipid metabolism, is associated with several neurodegenerative disorders including Alzheimer's disease. Despite numerous attempts to elucidate apoE gene regulation in the brain, the exact mechanism is still uncovered. The mechanism of apoE gene regulation in the brain involves the proximal promoter and multienhancers ME.1 and ME.2, which evolved by gene duplication. Herein we questioned whether thyroid hormones and their nuclear receptors have a role in apoE gene regulation in astrocytes. Our data showed that thyroid hormones increase apoE gene expression in HTB14 astrocytes in a dose-dependent manner. This effect can be intermediated by the thyroid receptor β (TRβ) which is expressed in these cells. In the presence of triiodothyronine (T3) and 9-cis retinoic acid, in astrocytes transfected to overexpress TRβ and retinoid X receptor α (RXRα), apoE promoter was indirectly activated through the interaction with ME.2. To determine the location of TRβ/RXRα binding site on ME.2, we performed DNA pull down assays and found that TRβ/RXRα complex bound to the region 341-488 of ME.2. This result was confirmed by transient transfection experiments in which a series of 5'- and 3'-deletion mutants of ME.2 were used. These data support the existence of a biologically active TRβ binding site starting at 409 in ME.2. In conclusion, our data revealed that ligand-activated TRβ/RXRα heterodimers bind with high efficiency on tissue-specific distal regulatory element ME.2 and thus modulate apoE gene expression in the brain.

  19. 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.

  20. Does Apolipoprotein E Genotype Increase Risk of Postoperative Delirium?

    PubMed Central

    Vasunilashorn, Sarinnapha; Ngo, Long; Kosar, Cyrus M.; Fong, Tamara G.; Jones, Richard N.

    2015-01-01

    Objectives To determine whether Apolipoprotein E (ApoE) is associated with postoperative delirium incidence, severity, and duration in older patients free of dementia at baseline. Design, Setting, Participants We examined 557 non-demented patients age ≥70 undergoing major non-cardiac surgery enrolled in the Successful Aging after Elective Surgery (SAGES) Study. Measurements We considered three ApoE measures: ε2, ε4 carriers vs. non-carriers, and a three-category ApoE measure. Delirium was determined using the Confusion Assessment Method (CAM) and chart review. We used generalized linear models to estimate the association between ApoE and delirium incidence, severity (peak CAM Severity [CAM-S] score), and days. Results ApoE ε2 and ε4 was present in 15% and 19% respectively, and postoperative delirium occurred in 24%. Among patients with delirium, the mean peak CAM-S score was 8.0 (standard deviation 4), with most patients experiencing one or two delirium days (51% or 28%, respectively). After adjusting for age, sex, surgical procedure, and preoperative cognitive function, ApoE ε4 and ε2 carrier status were not associated with postoperative delirium: RR for ε4=1.0, 95% confidence interval (CI) 0.7-1.5 and RR for ε2=0.9, 95% CI 0.6-1.4. No association between ApoE and delirium severity or number of delirium days was observed. Conclusions In older surgery patients free of dementia, our findings do not support the hypothesis that the ApoE genotype does not confer either risk or protection in postoperative delirium incidence, severity, or duration. Thus, an important genetic risk factor for Alzheimer's Disease does not affect risk of delirium. PMID:26238230

  1. Isoliquiritigenin Attenuates Atherogenesis in Apolipoprotein E-Deficient Mice

    PubMed Central

    Du, Fen; Gesang, Quzhen; Cao, Jia; Qian, Mei; Ma, Li; Wu, Dongfang; Yu, Hong

    2016-01-01

    Isoliquiritigenin (ISL) exhibits antioxidation and anti-inflammation activity. We sought to investigate the effects and mechanism of ISL on the development of atherosclerotic lesions in apolipoprotein E-deficient (apoE−/−) mice. Firstly, we determined that ISL reduced the mRNA levels of inflammatory factors interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and monocyte chemotactic protein-1 (MCP-1), while it increased the expression of several lipoprotein-related genes in peritoneal macrophages treated with lipopolysaccharide (LPS). ISL also enhanced peroxisome proliferator-activated receptor gamma (PPARγ) protein levels and reversed the changes of ATP-binding cassette transporter A (ABCA1) and cluster of differentiation 36 (CD36) in macrophages treated with oxidative low-density lipoprotein (ox-LDL). Then, in an in vivo study, female apoE−/− mice were fed a Western diet with ISL (0, 20, 100 mg/kg/day) added for 12 weeks. We found that ISL decreased the plasma cholesterol levels of very low-density lipoprotein (VLDL)/LDL, promoted plasma superoxide dismutase (SOD) and paraoxonase-1 (PON1) activities, and decreased plasma IL-6, TNF-α, and MCP-1 levels. Moreover, ISL significantly reduced the atherosclerotic lesions and hepatic steatosis in apoE−/− mice. In the liver, ISL altered the expression of several key genes (such as SRBI, ABCA1, ABCG8, PPARγ, and FASN) involving cholesterol-selective uptake and excretion into bile, triglyceride (TG) biosynthesis, and inflammation. These results suggest that the atheroprotective effects of ISL are due to the improvement of lipid metabolism, antioxidation, and anti-inflammation, which involve PPARγ-dependent signaling. PMID:27869741

  2. Apolipoprotein E Mediates Evasion From Hepatitis C Virus Neutralizing Antibodies.

    PubMed

    Fauvelle, Catherine; Felmlee, Daniel J; Crouchet, Emilie; Lee, JiYoung; Heydmann, Laura; Lefèvre, Mathieu; Magri, Andrea; Hiet, Marie-Sophie; Fofana, Isabel; Habersetzer, François; Foung, Steven K H; Milne, Ross; Patel, Arvind H; Vercauteren, Koen; Meuleman, Philip; Zeisel, Mirjam B; Bartenschlager, Ralf; Schuster, Catherine; Baumert, Thomas F

    2016-01-01

    Efforts to develop an effective vaccine against hepatitis C virus (HCV) have been hindered by the propensity of the virus to evade host immune responses. HCV particles in serum and in cell culture associate with lipoproteins, which contribute to viral entry. Lipoprotein association has also been proposed to mediate viral evasion of the humoral immune response, though the mechanisms are poorly defined. We used small interfering RNAs to reduce levels of apolipoprotein E (apoE) in cell culture-derived HCV-producing Huh7.5-derived hepatoma cells and confirmed its depletion by immunoblot analyses of purified viral particles. Before infection of naïve hepatoma cells, we exposed cell culture-derived HCV strains of different genotypes, subtypes, and variants to serum and polyclonal and monoclonal antibodies isolated from patients with chronic HCV infection. We analyzed the interaction of apoE with viral envelope glycoprotein E2 and HCV virions by immunoprecipitation. Through loss-of-function studies on patient-derived HCV variants of several genotypes and subtypes, we found that the HCV particle apoE allows the virus to avoid neutralization by patient-derived antibodies. Functional studies with human monoclonal antiviral antibodies showed that conformational epitopes of envelope glycoprotein E2 domains B and C were exposed after depletion of apoE. The level and conformation of virion-associated apoE affected the ability of the virus to escape neutralization by antibodies. In cell-infection studies, we found that HCV-associated apoE helps the virus avoid neutralization by antibodies against HCV isolated from chronically infected patients. This method of immune evasion poses a challenge for the development of HCV vaccines. Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.

  3. Nucleotide sequence and structure of the human apolipoprotein E gene.

    PubMed Central

    Paik, Y K; Chang, D J; Reardon, C A; Davies, G E; Mahley, R W; Taylor, J M

    1985-01-01

    The gene for human apolipoprotein E (apo-E) was selected from a library of cloned genomic DNA by screening with a specific cDNA hybridization probe, and its structure was characterized. The complete nucleotide sequence of the gene as well as 856 nucleotides of the 5' flanking region and 629 nucleotides of the 3' flanking region were determined. Analysis of the sequence showed that the mRNA-encoding region of the apo-E gene consists of four exons separated by three introns. In comparison to the structure of the mRNA, the introns are located in the 5' noncoding region, in the codon for glycine at position -4 of the signal peptide region, and in the codon for arginine at position +61 of the mature protein. The overall lengths of the apo-E gene and its corresponding mRNA are 3597 and 1163 nucleotides, respectively; a mature plasma protein of 299 amino acids is produced by this gene. Examination of the 5' terminus of the gene by S1 nuclease mapping shows apparent multiple transcription initiation sites. The proximal 5' flanking region contains a "TATA box" element as well as two nearby inverted repeat elements. In addition, there are four Alu family sequences associated with the apo-E gene: an Alu sequence located near each end of the gene and two Alu sequences located in the second intron. This knowledge of the structure permits a molecular approach to characterizing the regulation of the apo-E gene. Images PMID:2987927

  4. The distribution of apolipoprotein E alleles in Scottish perinatal deaths

    PubMed Central

    Becher, J‐C; Keeling, J W; McIntosh, N; Wyatt, B; Bell, J

    2006-01-01

    Background The apolipoprotein E (ApoE) polymorphism has been well studied in the adult human population, in part because the e4 allele is a known risk factor for Alzheimer's disease. Little is known of the distribution of ApoE alleles in newborns, and their association with perinatal brain damage has not been investigated. Methods ApoE genotyping was undertaken in a Scottish cohort of perinatal deaths (n = 261), some of whom had prenatal brain damage. The distribution of ApoE alleles in perinatal deaths was compared with that in healthy liveborn infants and in adults in Scotland. Results ApoE e2 was over‐represented in 251 perinatal deaths (13% v 8% in healthy newborns, odds ratio (OR) = 1.63, 95% confidence interval (CI) 1.13 to 2.36 and 13% v 8% in adults, OR = 1.67, 95% CI 1.16 to 2.41), both in liveborn and stillborn perinatal deaths. In contrast, the prevalence of ApoE e4 was raised in healthy liveborn infants (19%) compared with stillbirths (13%, OR = 1.59, 95% CI 1.11 to 2.26) and with adults (15%, OR = 1.35, 95% CI 1.04 to 1.76). However, no correlation was found between ApoE genotype and the presence or absence of perinatal brain damage. Conclusions This study shows a shift in ApoE allelic distribution in early life compared with adults. The raised prevalence of ApoE e2 associated with perinatal death suggests that this allele is detrimental to pregnancy outcome, whereas ApoE e4 may be less so. However, ApoE genotype did not appear to influence the vulnerability for perinatal hypoxic/ischaemic brain damage, in agreement with findings in adult brains and in animal models. PMID:16183800

  5. Pharmacogenomic effects of Apolipoprotein E on Intracerebral Hemorrhage

    PubMed Central

    James, Michael L.; Sullivan, Patrick M.; Lascola, Christopher D.; Vitek, Michael P.; Laskowitz, Daniel T.

    2009-01-01

    Background and Purpose To evaluate the effect of APOE genotype and the feasibility of administering an apoE-mimetic therapeutic to modify outcomes in a murine model of intracerebral hemorrhage (ICH). Methods ICH was induced via stereotactic injection of 0.1 U Clostridial collagenase into the left basal ganglia of wild-type (WT) and apolipoprotein-E targeted-replacement (APOETR) mice, consisting of either homozygous 3/3 (APOE3TR) or 4/4 (APOE4TR) genotypes. Animals were randomized to receive either vehicle or apoE-mimetic peptide. Outcomes included functional neurological tests (21-point neuroseverity score and rotorod latency) over the initial 7 d after injury, radiographic and histological hemorrhage size at 3 and 7 d, brain water content for cerebral edema at 24 h, and q-PCR for inflammatory markers at 6, 24, and 48 h. Results APOE3TR animals demonstrated superior neuroseverity scores and rotorod latencies over the first 3 d after ICH, decreased cerebral edema at 24 h, and reduced up-regulation of IL-6 and eNOS at 6 h when compared to their APOE4TR counterparts. Following intravenous administration of 1 mg/kg apoE-mimetic peptide, both WT and APOE4TR animals exhibited improved functional outcomes over 7 d after ICH, less edema at 24 h and reduced up-regulation of IL-6 and eNOS when compared to mice that did not receive the peptide. Conclusions Our data indicate that APOE genotype influences neurological outcome after ICH in a murine model. In particular APOE4 is associated with poor functional outcome and increased cerebral edema. Additionally, this outcome can be modified by the addition of an apoE mimetic-peptide, COG1410. PMID:19109539

  6. 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

  7. Gene dose of apolipoprotein E type 4 allele and the risk of Alzheimer's disease in late onset families

    SciTech Connect

    Corder, E.H.; Saunders, A.M.; Strittmatter, W.J.; Gaskell, P.C.; Roses, A.D.; Petricak-Vance, M.A. ); Schmechel, D.E. Durham VA Medical Center, CA ); Small, G.W. ); Haines, J.L. )

    1993-08-13

    The apolipoprotein E type 4 allele (APOE-[epsilon]4) is genetically associated with the common late onset familial and sporadic forms of Alzheimer's disease (AD). Risk for AD increased from 20% to 90% and mean age at onset decreased from 84 to 68 years with increasing number of APOE-[epsilon]4 alleles in 42 families with late onset AD. Thus APOE-[epsilon]4 gene dose is a major risk factor for late onset AD and, in these families, homozygosity for APOE-[epsilon]4 was virtually sufficient to cause AD by age 80.

  8. Inter-molecular crosslinking activity is engendered by the dimeric form of transglutaminase 2.

    PubMed

    Kim, Nayeon; Lee, Won-Kyu; Lee, Seon-Hyeong; Jin, Kyeong Sik; Kim, Kyung-Hee; Lee, Younho; Song, Minsoo; Kim, Soo-Youl

    2017-03-01

    Transglutaminase 2 (TGase 2) catalyzes a crosslink between protein bound-glutamine and -lysine. We proposed the mechanism of TGase 2 activation depends on conformation change from unfolded monomer to unfolded dimer. We found that TGase 2 has temperature-sensitive conformation change system at 30 °C. Small-angle X-ray scattering analysis showed that the enzyme was maintained as an unfolded monomer at temperatures below 30 °C, but changed to an unfolded dimer at over 30 °C. Mass analysis revealed that the C-terminus of TGase 2 was the critical region for dimerization. Furthermore, this conformational switch creates new biochemical reactivity that catalyzed inter-molecular crosslink at above 30 °C as an unfolded dimer of TGase 2 while catalyzed intra-molecular crosslink at below 30 °C as an unfolded monomer of TGase 2. The mechanism of TGase 2 activation depends on temperature-sensitive conformation change from unfolded monomer to unfolded dimer at over 30 °C. Furthermore, inter-molecular crosslinking activity is generated by the dimeric form of TGase 2. TGase 2 switches its conformation from a monomer to a dimer following a change in temperature, which engendered unique catalytic function of enzyme as inter-molecular crosslinking activity with calcium.

  9. Human apolipoprotein E expression in Escherichia coli: structural and functional identity of the bacterially produced protein with plasma apolipoprotein E.

    PubMed Central

    Vogel, T; Weisgraber, K H; Zeevi, M I; Ben-Artzi, H; Levanon, A Z; Rall, S C; Innerarity, T L; Hui, D Y; Taylor, J M; Kanner, D

    1985-01-01

    Human apolipoprotein E (apoE) was produced in Escherichia coli by transforming cells with an expression vector containing a reconstructed apoE cDNA, a lambda PL promoter regulated by the thermolabile cI repressor, and a ribosomal binding site derived from the lambda cII or the E. coli beta-lactamase gene. Transformed cells induced at 42 degrees C for short periods of time (less than 20 min) produced apoE, which accumulated in the cells at levels of approximately equal to 1% of the total soluble cellular protein. Longer induction periods resulted in cell lysis and the proteolytic destruction of apoE. The bacterially produced apoE was purified by heparin-Sepharose affinity chromatography, Sephacryl S-300 gel filtration, and preparative Immobiline isoelectric focusing. The final yield was approximately equal to 20% of the initial apoE present in the cells. Except for an additional methionine at the amino terminus, the bacterially produced apoE was indistinguishable from authentic human plasma apoE as determined by NaDodSO4 and isoelectric focusing gel electrophoresis, amino acid composition of the total protein as well as its cyanogen bromide fragments, and partial amino acid sequence analysis (residues 1-17 and 109-164). Both the bacterially produced and authentic plasma apoE bound similarly to apolipoprotein B,E(low density lipoprotein) receptors of human fibroblasts and to hepatic apoE receptors. Intravenous injection resulted in similar rates of clearance for both the bacterially produced and authentic apoE from rabbit and rat plasma (approximately equal to 50% removed in 20 min). The ability to synthesize a bacterially produced human apolipoprotein with biological properties indistinguishable from those of the native protein will allow the production of large quantities of apoE for use in further investigations of the biological and physiological properties of this apolipoprotein. Images PMID:3909150

  10. Nicotinamidase/pyrazinamidase of Mycobacterium tuberculosis forms homo-dimers stabilized by disulfide bonds

    PubMed Central

    Rueda, Daniel; Sheen, Patricia; Gilman, Robert H.; Bueno, Carlos; Santos, Marco; Pando-Robles, Victoria; Batista, Cesar V.; Zimic, Mirko

    2014-01-01

    Recombinant wild-pyrazinamidase from H37Rv M. tuberculosis was analyzed by gel electrophoresis under differential reducing conditions to evaluate its quaternary structure. PZAse was fractionated by size exclusion chromatography under non-reducing conditions. PZAse activity was measured and mass spectrometry analysis was performed to determine the identity of proteins by de novo sequencing and to determine the presence of disulfide bonds. This study confirmed that M. tuberculosis wild type PZAse was able to form homo-dimers in vitro. Homo-dimers showed a slightly lower specific PZAse activity compared to monomeric PZAse. PZAse dimers were dissociated into monomers in response to reducing conditions. Mass spectrometry analysis confirmed the existence of disulfide bonds (C72-C138 and C138-C138) stabilizing the quaternary structure of the PZAse homo-dimer. PMID:25199451

  11. Apolipoprotein E phenotypes in patients with gout: relation with hypertriglyceridaemia.

    PubMed Central

    Moriwaki, Y; Yamamoto, T; Takahashi, S; Tsutsumi, Z; Higashino, K

    1995-01-01

    OBJECTIVE--To elucidate the relationship, if any, between lipid abnormalities and apolipoprotein E (apo E) polymorphism, by investigating apo E phenotype and allele frequency. METHODS--Fasting blood samples were taken for determination of apo E phenotype and serum lipids in 221 male patients with gout and 141 control male subjects. Apo E phenotype was determined by one dimensional flat gel isoelectric focusing. RESULTS--Frequencies of apo E phenotypes in gout were apo E3/3 67.9%, E4/3 18.1%, E4/4 2.3%, E4/2 1.8%, E3/2 9.5%, and E2/2 0.5%; those in control male subjects were 74.5%, 15.6%, 0%, 1.4%, 7.1%, and 1.4%, respectively. Frequencies of the e2, e3, and e4 alleles in gout were 0.061, 0.817 and 0.122, compared with the corresponding control frequencies of 0.057, 0.858 and 0.085. These differences in apo E phenotype and allele frequencies between gout and control subjects were not significant. The frequency of apo e4 allele in hyperlipidaemic gout subjects was significantly greater than that in normolipidaemic gout subjects; in contrast, its frequency was not different between hyperlipidaemic and normolipidaemic control subjects. Serum triglyceride, total cholesterol, apo B and E concentrations were significantly greater in gouty patients with the apo E4/3 phenotype than in those with gout having the apo E3/3 phenotype. CONCLUSIONS--These data suggest that gout subjects with hyperlipidaemia (hypertriglyceridaemia, hypercholesterolaemia or both) possess the apo e4 allele with higher frequency than those with normolipidaemia. They also suggest that apo e4 may induce some susceptibility to the development of hyperlipidaemia in gout in addition to that induced by obesity or excessive alcohol consumption, and may contribute to the high prevalence of atherosclerotic diseases in gout patients. Images PMID:7794039

  12. Biomarkers Associated With the Apolipoprotein E Genotype and Alzheimer Disease

    PubMed Central

    Soares, Holly D.; Potter, William Z.; Pickering, Eve; Kuhn, Max; Immermann, Frederick W.; Shera, David M; Ferm, Mats; Dean, Robert A.; Simon, Adam J.; Swenson, Frank; Siuciak, Judith A.; Kaplow, June; Thambisetty, Madhav; Zagouras, Panayiotis; Koroshetz, Walter J.; Wan, Hong I.; Trojanowski, John Q.; Shaw, Leslie M.

    2013-01-01

    Background A blood-based test that could be used as a screen for Alzheimer disease (AD) may enable early intervention and better access to treatment. Objective To apply a multiplex immunoassay panel to identify plasma biomarkers of AD using plasma samples from the Alzheimer’s Disease Neuroimaging Initiative cohort. Design Cohort study. Setting The Biomarkers Consortium Alzheimer’s Disease Plasma Proteomics Project. Participants Plasma samples at baseline and at 1 year were analyzed from 396 (345 at 1 year) patients with mild cognitive impairment, 112 (97 at 1 year) patients with AD, and 58 (54 at 1 year) healthy control subjects. Main Outcome Measures Multivariate and univariate statistical analyses were used to examine differences across diagnostic groups and relative to the apolipoprotein E (ApoE) genotype. Results Increased levels of eotaxin 3, pancreatic polypeptide, and N-terminal protein B–type brain natriuretic peptide were observed in patients, confirming similar changes reported in cerebrospinal fluid samples of patients with AD and MCI. Increases in tenascin C levels and decreases in IgM and ApoE levels were also observed. All participants with Apo ε3/ε4 or ε4/ε4 alleles showed a distinct biochemical profile characterized by low C-reactive protein and ApoE levels and by high Cortisol, interleukin 13, apolipoprotein B, and gamma interferon levels. The use of plasma biomarkers improved specificity in differentiating patients with AD from controls, and ApoE plasma levels were lowest in patients whose mild cognitive impairment had progressed to dementia. Conclusions Plasma biomarker results confirm cerebrospinal fluid studies reporting increased levels of pancreatic polypeptide and N-terminal protein B–type brain natriuretic peptide in patients with AD and mild cognitive impairment. Incorporation of plasma biomarkers yielded high sensitivity with improved specificity, supporting their usefulness as a screening tool. The ApoE genotype was

  13. Thyroid hormones upregulate apolipoprotein E gene expression in astrocytes

    SciTech Connect

    Roman, Corina; Fuior, Elena V.; Trusca, Violeta G.; Kardassis, Dimitris; Simionescu, Maya; Gafencu, Anca V.

    2015-12-04

    Apolipoprotein E (apoE), a protein mainly involved in lipid metabolism, is associated with several neurodegenerative disorders including Alzheimer's disease. Despite numerous attempts to elucidate apoE gene regulation in the brain, the exact mechanism is still uncovered. The mechanism of apoE gene regulation in the brain involves the proximal promoter and multienhancers ME.1 and ME.2, which evolved by gene duplication. Herein we questioned whether thyroid hormones and their nuclear receptors have a role in apoE gene regulation in astrocytes. Our data showed that thyroid hormones increase apoE gene expression in HTB14 astrocytes in a dose-dependent manner. This effect can be intermediated by the thyroid receptor β (TRβ) which is expressed in these cells. In the presence of triiodothyronine (T3) and 9-cis retinoic acid, in astrocytes transfected to overexpress TRβ and retinoid X receptor α (RXRα), apoE promoter was indirectly activated through the interaction with ME.2. To determine the location of TRβ/RXRα binding site on ME.2, we performed DNA pull down assays and found that TRβ/RXRα complex bound to the region 341–488 of ME.2. This result was confirmed by transient transfection experiments in which a series of 5′- and 3′-deletion mutants of ME.2 were used. These data support the existence of a biologically active TRβ binding site starting at 409 in ME.2. In conclusion, our data revealed that ligand-activated TRβ/RXRα heterodimers bind with high efficiency on tissue-specific distal regulatory element ME.2 and thus modulate apoE gene expression in the brain. - Highlights: • T3 induce a dose-dependent increase of apoE expression in astrocytes. • Thyroid hormones activate apoE promoter in a cell specific manner. • Ligand activated TRβ/RXRα bind on the distal regulatory element ME.2 to modulate apoE. • The binding site of TRβ/RXRα heterodimer is located at 409 bp on ME.2.

  14. Specific Regional Transcription of Apolipoprotein E in Human Brain Neurons

    PubMed Central

    Xu, Pu-Ting; Gilbert, John R.; Qiu, Hui-Ling; Ervin, John; Rothrock-Christian, Tracie R.; Hulette, Christine; Schmechel, Donald E.

    1999-01-01

    In central nervous system injury and disease, apolipoprotein E (APOE, gene; apoE, protein) might be involved in neuronal injury and death indirectly through extracellular effects and/or more directly through intracellular effects on neuronal metabolism. Although intracellular effects could clearly be mediated by neuronal uptake of extracellular apoE, recent experiments in injury models in normal rodents and in mice transgenic for the human APOE gene suggest the additional possibility of intraneuronal synthesis. To examine whether APOE might be synthesized by human neurons, we performed in situ hybridization on paraffin-embedded and frozen brain sections from three nondemented controls and five Alzheimer’s disease (AD) patients using digoxigenin-labeled antisense and sense cRNA probes to human APOE. Using the antisense APOE probes, we found the expected strong hybridization signal in glial cells as well as a generally fainter signal in selected neurons in cerebral cortex and hippocampus. In hippocampus, many APOE mRNA-containing neurons were observed in sectors CA1 to CA4 and the granule cell layer of the dentate gyrus. In these regions, APOE mRNA containing neurons could be observed adjacent to nonhybridizing neurons of the same cell class. APOE mRNA transcription in neurons is regionally specific. In cerebellar cortex, APOE mRNA was seen only in Bergmann glial cells and scattered astrocytes but not in Purkinje cells or granule cell neurons. ApoE immunocytochemical localization in semi-adjacent sections supported the selectivity of APOE transcription. These results demonstrate the expected result that APOE mRNA is transcribed and expressed in glial cells in human brain. The important new finding is that APOE mRNA is also transcribed and expressed in many neurons in frontal cortex and human hippocampus but not in neurons of cerebellar cortex from the same brains. This regionally specific human APOE gene expression suggests that synthesis of apoE might play a role

  15. Selective and asymmetric action of trypsin on the dimeric forms of seminal RNase.

    PubMed Central

    De Lorenzo, C.; Dal Piaz, F.; Piccoli, R.; Di Maro, A.; Pucci, P.; D'Alessio, G.

    1998-01-01

    Dimeric seminal RNase (BS-RNase) is an equilibrium mixture of conformationally different quaternary structures, one characterized by the interchange between subunits of their N-terminal ends (the MXM form); the other with no interchange (the M=M form). Controlled tryptic digestion of each isolated quaternary form generates, as limit digest products, folded and enzymatically active molecules, very resistant to further tryptic degradation. Electrospray mass spectrometric analyses and N-terminal sequence determinations indicate that trypsin can discriminate between the conformationally different quaternary structures of seminal RNase, and exerts a differential and asymmetric action on the two dimeric forms, depending on the original quaternary conformation of each form. The two digestion products from the MXM and the M=M dimeric forms have different structures, which are reminiscent of the original quaternary conformation of the dimers: one with interchange, the other with no interchange, of the N-terminal ends. The surprising resistance of these tryptic products to further tryptic action is explained by the persistence in each digestion product of the original intersubunit interface. PMID:9865960

  16. Encasing of Na+ ion in dimer-formed acetic acid clusters.

    PubMed

    Di Palma, Tonia M; Bende, Attila

    2015-10-01

    Peaks with anomalous abundance found in the mass spectra are associated with ions with enhanced stability. Among the scientific community focused on mass spectrometry, these peaks are called 'magic peaks' and their stability is often because of suggestive symmetric structures. Here, we report findings on ionised Na-acetic acid clusters [Na(+) -(AcA)n ] produced by Na-doping of (AcA)n and UV laser ionisation. Peaks labelled n = 2, 4, 8 are clearly distinguishable in the mass spectra from their anomalous intensity. Ab initio calculations helped elucidate cluster structures and energetic. A plausible interpretation of the magic peaks is given in terms of (AcA)n formed by dimer aggregation. The encasing of Na(+) by twisted dimers is proposed to be the origin of the enhanced cluster stability. A conceivable dimer-formed tube-like closed structure is found for the Na(+) -(AcA)8 . Copyright © 2015 John Wiley & Sons, Ltd.

  17. Cardiovascular effects of uremia in apolipoprotein E-deficient mice.

    PubMed

    Bro, Susanne

    2009-11-01

    The purpose of this thesis work was to establish an experimental mouse model for studying the pathogenesis and therapy of accelerated atherosclerosis in uremia. Uremia was induced by surgical 5/6 nephrectomy in apolipoprotein E-deficient (apoE-/-) mice and led to development of severe aortic atherosclerosis independently of BP and plasma homocysteine levels. Also, the accelerated atherosclerosis could not be fully explained by changes in total plasma cholesterol. Morphologic and biochemical analyses of aortas suggested that accelerated initiation and expansion rather than a specific uremic lesion composition characterize atherosclerosis in the uremic mice. Increased expression of inflammatory genes in aortas of uremic mice suggests that an augmented inflammatory response in the arterial wall might be an important impetus for accelerated atherosclerosis in uremia. A marked downregulation of expression of smooth muscle cell assigned genes indicates that besides intimal atherosclerosis, uremic vasculopathy in apoE-/- mice is characterized by a uremia-specific medial smooth muscle cell degeneration. Oxidative stress could also be important for the development of atherosclerotic lesions in uremia. In the mouse model, uremia led to a marked increase of titers of antibodies against oxidized LDL (OxLDL), and increased circulating levels of the oxidized phospholipid epitope EO6. Treatment with enalapril (an ACE inhibitor) almost completely prevented the development of accelerated aortic atherosclerosis in uremic mice. This effect was parallelled by reductions of aortic expression of the proinflammatory adhesion molecule VCAM-1, and plasma titers of IgM antibodies against OxLDL, and was at least partly independent of BP-lowering. To test the involvement of the receptor for advanced glycation end products (RAGE) in development of uremic atherosclerosis, uremic mice were treated with a neutralizing RAGE-antibody. This treatment reduced the aortic plaque area fraction by 59% in

  18. Dynamics of water molecules buried in cavities of apolipoprotein E studied by molecular dynamics simulations and continuum electrostatic calculations.

    PubMed

    Prévost, Martine

    2004-10-05

    Molecular dynamics (MD) simulations of several nanoseconds each were used to monitor the dynamic behavior of the five crystal water molecules buried in the interior of the N-terminal domain of apolipoprotein E. These crystal water molecules are fairly well conserved in several apolipoprotein E structures, suggesting that they are not an artifact of the crystal and that they may have a structural and/or functional role for the protein. All five buried crystal water molecules leave the protein interior in the course of the longest simulations and exchange with water molecules from the bulk. The free energies of binding evaluated from the electrostatic binding free energy computed using a continuum model and estimates of the binding entropy changes represent shallow minima. The corresponding calculated residence times of the buried water molecules range from tens of picoseconds to hundreds of nanoseconds, which denote rather short times as for buried water molecules. Several water exchanges monitored in the simulations show that water molecules along the exit/entrance pathway use a relay of H bonds primarily formed with charged residues which helps either the exit or the entrance from or into the buried site. The exit/entrance of water molecules from/into the sites is permitted essentially by local motions of, at most, two side chains, indicating that, in these cases, complex correlated atomic motions are not needed to open the buried site toward the surface of the protein. This provides a possible explanation for the short residence times.

  19. Apolipoprotein E-Mimetics Inhibit Neurodegeneration and Restore Cognitive Functions in a Transgenic Drosophila Model of Alzheimer's Disease

    PubMed Central

    Sarantseva, Svetlana; Timoshenko, Svetlana; Bolshakova, Olga; Karaseva, Eugenia; Rodin, Dmitry; Schwarzman, Alexander L.; Vitek, Michael P.

    2009-01-01

    Background Mutations of the amyloid precursor protein gene (APP) are found in familial forms of Alzheimer's disease (AD) and some lead to the elevated production of amyloid-β-protein (Aβ). While Aβ has been implicated in the causation of AD, the exact role played by Aβ and its APP precursor are still unclear. Principal Findings In our study, Drosophila melanogaster transgenics were established as a model to analyze AD-like pathology caused by APP overexpression. We demonstrated that age related changes in the levels and pattern of synaptic proteins accompanied progressive neurodegeneration and impairment of cognitive functions in APP transgenic flies, but that these changes may be independent from the generation of Aβ. Using novel peptide mimetics of Apolipoprotein-E, COG112 or COG133 proved to be neuroprotective and significantly improved the learning and memory of APP transgenic flies. Conclusions The development of neurodegeneration and cognitive deficits was corrected by injections of COG112 or COG133, novel mimetics of apolipoprotein-E (apoE) with neuroprotective activities. PMID:19997607

  20. Orphan nuclear receptor NGFI-B forms dimers with nonclassical interface

    PubMed Central

    Calgaro, Marcos R.; Neto, Mario de Oliveira; Figueira, Ana Carolina M.; Santos, Maria A.M.; Portugal, Rodrigo V.; Guzzi, Carolina A.; Saidemberg, Daniel M.; Bleicher, Lucas; Vernal, Javier; Fernandez, Pablo; Terenzi, Hernán; Palma, Mario Sergio; Polikarpov, Igor

    2007-01-01

    The orphan receptor nerve growth factor-induced B (NGFI-B) is a member of the nuclear receptor's subfamily 4A (Nr4a). NGFI-B was shown to be capable of binding both as a monomer to an extended half-site containing a single AAAGGTCA motif and also as a homodimer to a widely separated everted repeat, as opposed to a large number of nuclear receptors that recognize and bind specific DNA sequences predominantly as homo- and/or heterodimers. To unveil the structural organization of NGFI-B in solution, we determined the quaternary structure of the NGFI-B LBD by a combination of ab initio procedures from small-angle X-ray scattering (SAXS) data and hydrogen–deuterium exchange followed by mass spectrometry. Here we report that the protein forms dimers in solution with a radius of gyration of 2.9 nm and maximum dimension of 9.0 nm. We also show that the NGFI-B LBD dimer is V-shaped, with the opening angle significantly larger than that of classical dimer's exemplified by estrogen receptor (ER) or retinoid X receptor (RXR). Surprisingly, NGFI-B dimers formation does not occur via the classical nuclear receptor dimerization interface exemplified by ER and RXR, but instead, involves an extended surface area composed of the loop between helices 3 and 4 and C-terminal fraction of the helix 3. Remarkably, the NGFI-B dimer interface is similar to the dimerization interface earlier revealed for glucocorticoid nuclear receptor (GR), which might be relevant to the recognition of cognate DNA response elements by NGFI-B and to antagonism of NGFI-B–dependent transcription exercised by GR in cells. PMID:17600153

  1. Resonance assignments and secondary structure of apolipoprotein E C-terminal domain in DHPC micelles.

    PubMed

    Lo, Chi-Jen; Chyan, Chia-Lin; Chen, Yi-Chen; Chang, Chi-Fon; Huang, Hsien-Bin; Lin, Ta-Hsien

    2015-04-01

    Human apolipoprotein E (apoE) has been known to play a key role in the transport of plasma cholesterol and lipoprotein metabolism. It is an apolipoprotein of 299 amino acids with a molecular mass, ~34 kDa. ApoE has three major isoforms, apoE2, apoE3, and apoE4 which differ only at residue 112 or 158. ApoE consists of two independently folded domains (N-terminal and C-terminal domain) separated by a hinge region. The N-terminal domain and C-terminal domain of apoE are responsible for the binding to receptor and to lipid, respectively. Since the high resolution structures of apoE in lipids are still unavailable to date, we therefore aim to resolve the structures in lipids by NMR. Here, we reported the resonance assignments and secondary structure distribution of the C-terminal domain of wild-type human apoE (residue 195-299) in the micelles formed by dihexanoylphosphatidylcholine. Our results may provide a novel structural model of apoE in micelles and may shed new light on the molecular mechanisms underlying the apoE related biological processes.

  2. 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.

  3. The cytoplasmic domain of the T-cell receptor zeta subunit does not form disordered dimers

    PubMed Central

    Nourse, Amanda; Mittag, Tanja

    2013-01-01

    Intrinsically disordered regions in proteins play active roles in recognition, signaling and molecular sorting. They often undergo coupled folding and binding giving rise to largely ordered interfaces with their binding partners. The cytoplasmic region of the T-cell receptor zeta subunit (ζcyt) has previously been proposed to specifically dimerize in the absence of a disorder-to-order transition, suggesting an intriguing dimerization mechanism that may involve multiple transient interfaces. We show here using analytical ultracentrifugation, NMR, size-exclusion chromatography and multi-angle light scattering that neither ζcyt nor the cytoplasmic region of CD3ε significantly populate a dimeric state, but that they are mostly monomers in solution up to millimolar concentrations. They experience a salt- and concentration-dependent shift of their elution volume in size exclusion chromatography previously interpreted as dimerization. Our data shows that ζcyt does not form a highly disordered protein complex and leaves open the question as to whether completely disordered dimers (or other oligomers) exist in nature. PMID:24120941

  4. The cytoplasmic domain of the T-cell receptor zeta subunit does not form disordered dimers.

    PubMed

    Nourse, Amanda; Mittag, Tanja

    2014-01-09

    Intrinsically disordered regions in proteins play active roles in recognition, signaling and molecular sorting. They often undergo coupled folding and binding giving rise to largely ordered interfaces with their binding partners. The cytoplasmic region of the T-cell receptor zeta subunit (ζcyt) has been previously proposed to specifically dimerize in the absence of a disorder-to-order transition, suggesting an intriguing dimerization mechanism that may involve multiple transient interfaces. We show here using analytical ultracentrifugation, NMR, size-exclusion chromatography (SEC) and multi-angle light scattering that neither ζcyt nor the cytoplasmic region of CD3ε significantly populates a dimeric state but that they are mostly monomers in solution up to millimolar concentrations. They experience a salt- and concentration-dependent shift of their elution volume in SEC previously interpreted as dimerization. Our data show that ζcyt does not form a highly disordered protein complex and leaves open the question as to whether completely disordered dimers (or other oligomers) exist in nature. © 2013 Elsevier Ltd. All rights reserved.

  5. Insulin resistance, dyslipidemia, and apolipoprotein E interactions as mechanisms in cognitive impairment and Alzheimer's disease

    PubMed Central

    Salameh, Therese S; Rhea, Elizabeth M; Hanson, Angela J

    2016-01-01

    An increased risk for Alzheimer's disease is associated with dyslipidemia and insulin resistance. A separate literature shows the genetic risk for developing Alzheimer's disease is strongly correlated to the presence of the E4 isoform of the apolipoprotein E carrier protein. Understanding how apolipoprotein E carrier protein, lipids, amyloid β peptides, glucose, central nervous system insulin, and peripheral insulin interact with one another in Alzheimer's disease is an area of increasing interest. Here, we will review the evidence relating apolipoprotein E carrier protein, lipids, and insulin action to Alzheimer's disease and Aβ peptides and then propose mechanisms as to how these factors might interact with one another to impair cognition and promote Alzheimer's disease. PMID:27470930

  6. Dihydroxyacetone phosphate, DHAP, in the crystalline state: monomeric and dimeric forms.

    PubMed

    Slepokura, Katarzyna; Lis, Tadeusz

    2010-02-26

    It was shown that dihydroxyacetone phosphate may exist in both monomeric DHAP (C(3)H(7)O(6)P) and dimeric DHAP-dimer (C(6)H(14)O(12)P(2)) form. Monomeric DHAP was obtained in the form of four crystalline salts: CaCl(DHAP) x 2.9H(2)O (7a), Ca(2)Cl(3)(DHAP) x 5H(2)O (7b), CaCl(DHAP) x 2H(2)O (7c), and CaBr(DHAP) x 5H(2)O (7d) by crystallization from aqueous solutions containing DHAP acid and CaCl(2) or CaBr(2), or by direct crystallization from a solution containing DHAP precursor and CaCl(2). At least one of the salts is stable and may be stored in the crystalline state at room temperature for several months. The dimeric form was obtained by slow saturation of free DHAP syrup with ammonia at -18 degrees C and isolated in the form of its hydrated diammonium salt (NH(4))(2)(DHAP-dimer) x 4H(2)O (8). The synthesis of the compounds, their crystallization, and crystal structures determined by X-ray crystallography are described. In all 7a-d monomeric DHAP exists in the monoanionic form in an extended (in-plane) cisoid conformation, with both hydroxyl and ester oxygen atoms being synperiplanar to the carbonyl O atom. The crucial structural feature is the coordination manner, in which the terminal phosphate oxygen atoms act as chelating as well as bridging atoms for the calcium cations. Additionally, the DHAP monoanions chelate another Ca(2+) by the alpha-hydroxycarbonyl moiety, in a manner observed previously in dihydroxyacetone (DHA) calcium chloride complexes. In dimeric 8 the anion is a trans isomer with the dioxane ring in a chair conformation with the hydroxyl groups in axial positions and the phosphomethyl group in an equatorial position.

  7. Active monomeric and dimeric forms of Pseudomonas putida glyoxalase I: evidence for 3D domain swapping.

    PubMed

    Saint-Jean, A P; Phillips, K R; Creighton, D J; Stone, M J

    1998-07-21

    3D domain swapping of proteins involves the interconversion of a monomer containing a single domain-domain interface and a 2-fold symmetrical dimer containing two equivalent intermolecular interfaces. Human glyoxalase I has the structure of a domain-swapped dimer [Cameron, A. D., Olin, B., Ridderström, M., Mannervik, B., and Jones, T. A. (1997) EMBO J. 16, 3386-3395] but Pseudomonas putida glyoxalase I has been reported to be monomeric [Rhee, H.-I., Murata, K., and Kimura, A. (1986) Biochem. Biophys. Res. Commun. 141, 993-999]. We show here that recombinant P. putida glyoxalase I is an active dimer (kcat approximately 500 +/- 100 s-1; KM approximately 0.4 +/- 0.2 mM) with two zinc ions per dimer. The zinc is required for structure and function. However, treatment of the dimer with glutathione yields an active monomer (kcat approximately 115 +/- 40 s-1; KM approximately 1.4 +/- 0.4 mM) containing a single zinc ion. The monomer is metastable and slowly reverts to the active dimer in the absence of glutathione. Thus, glyoxalase I appears to be a novel example of a single protein able to exist in two alternative domain-swapped forms. It is unique among domain-swapped proteins in that the active site and an essential metal binding site are apparently disassembled and reassembled by the process of domain swapping. Furthermore, it is the only example to date in which 3D domain swapping can be regulated by a small organic ligand.

  8. Structural characterization suggests models for monomeric and dimeric forms of full-length ezrin.

    PubMed

    Phang, Juanita M; Harrop, Stephen J; Duff, Anthony P; Sokolova, Anna V; Crossett, Ben; Walsh, James C; Beckham, Simone A; Nguyen, Cuong D; Davies, Roberta B; Glöckner, Carina; Bromley, Elizabeth H C; Wilk, Krystyna E; Curmi, Paul M G

    2016-09-15

    Ezrin is a member of the ERM (ezrin-radixin-moesin) family of proteins that have been conserved through metazoan evolution. These proteins have dormant and active forms, where the latter links the actin cytoskeleton to membranes. ERM proteins have three domains: an N-terminal FERM [band Four-point-one (4.1) ERM] domain comprising three subdomains (F1, F2, and F3); a helical domain; and a C-terminal actin-binding domain. In the dormant form, FERM and C-terminal domains form a stable complex. We have determined crystal structures of the active FERM domain and the dormant FERM:C-terminal domain complex of human ezrin. We observe a bistable array of phenylalanine residues in the core of subdomain F3 that is mobile in the active form and locked in the dormant form. As subdomain F3 is pivotal in binding membrane proteins and phospholipids, these transitions may facilitate activation and signaling. Full-length ezrin forms stable monomers and dimers. We used small-angle X-ray scattering to determine the solution structures of these species. As expected, the monomer shows a globular domain with a protruding helical coiled coil. The dimer shows an elongated dumbbell structure that is twice as long as the monomer. By aligning ERM sequences spanning metazoan evolution, we show that the central helical region is conserved, preserving the heptad repeat. Using this, we have built a dimer model where each monomer forms half of an elongated antiparallel coiled coil with domain-swapped FERM:C-terminal domain complexes at each end. The model suggests that ERM dimers may bind to actin in a parallel fashion.

  9. Does Possession of Apolipoprotein E[superscript E]4 Benefit Cognitive Function in Healthy Young Adults?

    ERIC Educational Resources Information Center

    Bunce, David; Anstey, Kaarin J.; Burns, Richard; Christensen, Helen; Easteal, Simon

    2011-01-01

    There is considerable evidence that the apolipoprotein E (APOE)[superscript E]4 allele is associated with cognitive deficits in older persons, and is a risk factor for dementia. However, it has recently been suggested that possession of the [superscript E]4 allele may benefit cognition in early adulthood. We tested this possibility in 5445…

  10. Apolipoprotein E gene polymorphisms and retinal vascular signs: The Atherosclerosis Risk in Communities (ARIC) Study

    USDA-ARS?s Scientific Manuscript database

    Our objective was to examine the association between apolipoprotein E (APOE) gene polymorphisms and retinal microvascular signs. We used a population-based, cross-sectional study. Participants from the Atherosclerosis Risk in Communities Study (n=10,036; aged 49-73 years) had retinal photographs tak...

  11. HIV-1 DIS stem loop forms an obligatory bent kissing intermediate in the dimerization pathway

    PubMed Central

    Mundigala, Hansini; Michaux, Jonathan B.; Feig, Andrew L.; Ennifar, Eric; Rueda, David

    2014-01-01

    The HIV-1 dimerization initiation sequence (DIS) is a conserved palindrome in the apical loop of a conserved hairpin motif in the 5′-untranslated region of its RNA genome. DIS hairpin plays an important role in genome dimerization by forming a ‘kissing complex’ between two complementary hairpins. Understanding the kinetics of this interaction is key to exploiting DIS as a possible human immunodeficiency virus (HIV) drug target. Here, we present a single-molecule Förster resonance energy transfer (smFRET) study of the dimerization reaction kinetics. Our data show the real-time formation and dissociation dynamics of individual kissing complexes, as well as the formation of the mature extended duplex complex that is ultimately required for virion packaging. Interestingly, the single-molecule trajectories reveal the presence of a previously unobserved bent intermediate required for extended duplex formation. The universally conserved A272 is essential for the formation of this intermediate, which is stabilized by Mg2+, but not by K+ cations. We propose a 3D model of a possible bent intermediate and a minimal dimerization pathway consisting of three steps with two obligatory intermediates (kissing complex and bent intermediate) and driven by Mg2+ ions. PMID:24813449

  12. HIV-1 DIS stem loop forms an obligatory bent kissing intermediate in the dimerization pathway.

    PubMed

    Mundigala, Hansini; Michaux, Jonathan B; Feig, Andrew L; Ennifar, Eric; Rueda, David

    2014-06-01

    The HIV-1 dimerization initiation sequence (DIS) is a conserved palindrome in the apical loop of a conserved hairpin motif in the 5'-untranslated region of its RNA genome. DIS hairpin plays an important role in genome dimerization by forming a 'kissing complex' between two complementary hairpins. Understanding the kinetics of this interaction is key to exploiting DIS as a possible human immunodeficiency virus (HIV) drug target. Here, we present a single-molecule Förster resonance energy transfer (smFRET) study of the dimerization reaction kinetics. Our data show the real-time formation and dissociation dynamics of individual kissing complexes, as well as the formation of the mature extended duplex complex that is ultimately required for virion packaging. Interestingly, the single-molecule trajectories reveal the presence of a previously unobserved bent intermediate required for extended duplex formation. The universally conserved A272 is essential for the formation of this intermediate, which is stabilized by Mg(2+), but not by K(+) cations. We propose a 3D model of a possible bent intermediate and a minimal dimerization pathway consisting of three steps with two obligatory intermediates (kissing complex and bent intermediate) and driven by Mg(2+) ions. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  13. A detailed MSn study for the molecular identification of a dimer formed from oxidation of pinene

    NASA Astrophysics Data System (ADS)

    Beck, Martin; Hoffmann, Thorsten

    2016-04-01

    Dimeric products formed in the oxidation of α- and β-pinene have been frequently observed in laboratory and field studies of biogenic SOA formation. While their existence is undoubted, their exact chemical structures remain unclear. This study uses a combined two step approach aiming on the molecular identification of the most important of the various dimers that have been observed in biogenic secondary organic aerosol formation, a dimer with the molecular weight 358 g mol-1. The first step is the application of a functional group derivatization technique (esterification) to quantify the number of carboxylic acid groups in the target molecule. Based on the detailed interpretation of the MSn spectra (up to n = 7) of the derivatized product further information about the exact structure of the compound of interest is compiled. To increase the intensity of precursor ions for the MSn-studies and especially to facilitate successive fragmentation of the target molecule, which yields structurally informative product spectra, cationization reagents (Li+, NH4+) are introduced. The results clearly point to the formation of a dimer containing three carboxylic acid groups and a structure containing a terpenylic acid building block and a pinic acid building block, strongly supporting a structure suggestion by Claeys and coworkers (Yasmeen et al., 2010).

  14. The HPr Proteins from the Thermophile Bacillus stearothermophilus Can Form Domain-swapped Dimers

    SciTech Connect

    Sridharan, Sudharsan; Razvi, Abbas; Scholtz, J. Martin; Sacchettini, James C.

    2010-07-20

    The study of proteins from extremophilic organisms continues to generate interest in the field of protein folding because paradigms explaining the enhanced stability of these proteins still elude us and such studies have the potential to further our knowledge of the forces stabilizing proteins. We have undertaken such a study with our model protein HPr from a mesophile, Bacillus subtilis, and a thermophile, Bacillus stearothermophilus. We report here the high-resolution structures of the wild-type HPr protein from the thermophile and a variant, F29W. The variant proved to crystallize in two forms: a monomeric form with a structure very similar to the wild-type protein as well as a domain-swapped dimer. Interestingly, the structure of the domain-swapped dimer for HPr is very different from that observed for a homologous protein, Crh, from B. subtilis. The existence of a domain-swapped dimer has implications for amyloid formation and is consistent with recent results showing that the HPr proteins can form amyloid fibrils. We also characterized the conformational stability of the thermophilic HPr proteins using thermal and solvent denaturation methods and have used the high-resolution structures in an attempt to explain the differences in stability between the different HPr proteins. Finally, we present a detailed analysis of the solution properties of the HPr proteins using a variety of biochemical and biophysical methods.

  15. Beta-amyloid protein-containing inclusions in skeletal muscle of apolipoprotein-E-deficient mice.

    PubMed Central

    Robertson, T. A.; Dutton, N. S.; Martins, R. N.; Roses, A. D.; Kakulas, B. A.; Papadimitriou, J. M.

    1997-01-01

    The tibialis anterior muscle and soleus muscle of apolipoprotein-E-deficient mice were examined by light and electron microscopy. By light microscopy, sarcoplasmic inclusions were seen in tibialis anterior muscle and 40% of type 2 myofibers were affected in all animals over 8 months of age. These inclusions reacted for nonspecific esterase, cytochrome oxidase, and myoadenylate deaminase and were also periodic acid Schiff positive and stained basophilic with hematoxylin. Moreover, they reacted immunocytochemically with an antibody specific to fragment 17 to 24 of the published sequence of Alzheimer's cerebrovascular amyloid peptide. Immunoreactivity was lost when the antibody was adsorbed with the appropriate synthetic peptide. Ultrastructurally, the inclusions consisted of tubular arrays and were similar to those observed in human muscle in several pathological conditions. In type 1 myofibers of both tibialis anterior and soleus muscle, however, mitochondrial abnormalities including an increase in their number and size were detected, but tubular aggregates were not seen. These large mitochondria possessed an electron-dense inner chamber with an increased number of tightly packed cristae. The results obtained suggest that in these mice there is a disturbed lipid metabolism in skeletal muscle fibers that manifests itself with an accumulation of phospholipid in the form of sarcoplasmic reticulum tubules in the type 2 fibers and enlarged mitochondria with tightly packed cristae in the type 1 fibers. In addition, beta-amyloid protein was closely associated with the accumulated tubules and vesicles of sarcoplasmic reticulum and may represent dysregulation of amyloid precursor protein metabolism. Images Figure 1 Figure 2 Figure 3 PMID:9033257

  16. Rosuvastatin reduces atherosclerotic lesions and promotes progenitor cell mobilisation and recruitment in apolipoprotein E knockout mice.

    PubMed

    Schroeter, Marco R; Humboldt, Tim; Schäfer, Katrin; Konstantinides, Stavros

    2009-07-01

    Statins enhance incorporation of bone marrow-derived cells into experimental neointimal lesions. However, the contribution of progenitor cells to progression of spontaneous atherosclerotic plaques, and the possible modulatory role of statins in this process, remain poorly understood. We compared the effects of rosuvastatin (1 and 10mg/kg BW) and pravastatin (10mg/kg) on progenitor cell mobilisation, recruitment into atherosclerotic plaques, and lesion growth. Statins were administered over 8 weeks to apolipoprotein E knockout mice on atherogenic diet. In addition, mice were lethally irradiated, followed by transplantation of bone marrow from LacZ transgenic mice. Rosuvastatin reduced lesion area and intima-to-media ratio at the brachiocephalic artery compared to vehicle, while both parameters were not significantly altered by pravastatin. Rosuvastatin also augmented endothelialisation (P<0.05) and reduced the smooth muscle cells (SMC) content (P=0.042) of lesions. Numbers of c-kit, sca-1 and flk-1, sca-1 double-positive progenitor cells were significantly increased in rosuvastatin compared to control-treated mice, both in the bone marrow and the peripheral blood. Similarly, the number of spleen-derived acLDL, lectin double-positive progenitor cells (P=0.001) and colony-forming units (P=0.0104) was significantly increased in mice treated with rosuvastatin compared to vehicle alone. In the bone marrow, increased Akt and p42/44 MAP kinase phosphorylation and upregulated SDF1alpha mRNA expression were observed. Importantly, rosuvastatin treatment also increased the plasma levels of c-kit ligand (P=0.003), and the number of c-kit-positive cells within atherosclerotic lesions (P=0.041). Our findings suggest that rosuvastatin reduces the size of atherosclerotic plaques, and this effect appears to involve progenitor cell mobilisation and recruitment into vascular lesions.

  17. Synapsis-Mediated Fusion of Free DNA Ends Forms Inverted Dimer Plasmids in Yeast

    PubMed Central

    Kunes, S.; Botstein, D.; Fox, M. S.

    1990-01-01

    When yeast (Saccharomyces cerevisiae) is transformed with linearized plasmid DNA and the ends of the plasmid do not share homology with the yeast genome, circular inverted (head-to-head) dimer plasmids are the principal product of repair. By measurements of the DNA concentration dependence of transformation with a linearized plasmid, and by transformation with mixtures of genetically marked plasmids, we show that two plasmid molecules are required to form an inverted dimer plasmid. Several observations suggest that homologous pairing accounts for the head-to-head joining of the two plasmid molecules. First, an enhanced frequency of homologous recombination is detected when genetically marked plasmids undergo end-to-end fusion. Second, when a plasmid is linearized within an inverted repeat, such that its ends could undergo head-to-tail homologous pairing, it is repaired by intramolecular head-to-tail joining. Last, in the joining of homologous linearized plasmids of different length, a shorter molecule can acquire a longer plasmid end by homologous recombination. The formation of inverted dimer plasmids may be related to some forms of chromosomal rearrangement. These might include the fusion of broken sister chromatids in the bridge-breakage-fusion cycle and the head-to-head duplication of genomic DNA at the sites of gene amplifications. PMID:2407606

  18. Monomeric banana lectin at acidic pH overrules conformational stability of its native dimeric form.

    PubMed

    Khan, Javed M; Qadeer, Atiyatul; Ahmad, Ejaz; Ashraf, Raghib; Bhushan, Bharat; Chaturvedi, Sumit K; Rabbani, Gulam; Khan, Rizwan H

    2013-01-01

    Banana lectin (BL) is a homodimeric protein categorized among jacalin-related family of lectins. The effect of acidic pH was examined on conformational stability of BL by using circular dichroism, intrinsic fluorescence, 1-anilino-8-napthalene sulfonate (ANS) binding, size exclusion chromatography (SEC) and dynamic light scattering (DLS). During acid denaturation of BL, the monomerization of native dimeric protein was found at pH 2.0. The elution profile from SEC showed two different peaks (59.65 ml & 87.98 ml) at pH 2.0 while single peak (61.45 ml) at pH 7.4. The hydrodynamic radii (R h) of native BL was 2.9 nm while at pH 2.0 two species were found with R h of 1.7 and 3.7 nm. Furthermore at, pH 2.0 the secondary structures of BL remained unaltered while tertiary structure was significantly disrupted with the exposure of hydrophobic clusters confirming the existence of molten globule like state. The unfolding of BL with different subunit status was further evaluated by urea and temperature mediated denaturation to check their stability. As inferred from high Cm and ΔG values, the monomeric form of BL offers more resistance towards chemical denaturation than the native dimeric form. Besides, dimeric BL exhibited a Tm of 77°C while no loss in secondary structures was observed in monomers even up to 95°C. To the best of our knowledge, this is the first report on monomeric subunit of lectins showing more stability against denaturants than its native dimeric state.

  19. SOXE transcription factors form selective dimers on non-compact DNA motifs through multifaceted interactions between dimerization and high-mobility group domains.

    PubMed

    Huang, Yong-Heng; Jankowski, Aleksander; Cheah, Kathryn S E; Prabhakar, Shyam; Jauch, Ralf

    2015-05-27

    The SOXE transcription factors SOX8, SOX9 and SOX10 are master regulators of mammalian development directing sex determination, gliogenesis, pancreas specification and neural crest development. We identified a set of palindromic SOX binding sites specifically enriched in regulatory regions of melanoma cells. SOXE proteins homodimerize on these sequences with high cooperativity. In contrast to other transcription factor dimers, which are typically rigidly spaced, SOXE group proteins can bind cooperatively at a wide range of dimer spacings. Using truncated forms of SOXE proteins, we show that a single dimerization (DIM) domain, that precedes the DNA binding high mobility group (HMG) domain, is sufficient for dimer formation, suggesting that DIM : HMG rather than DIM:DIM interactions mediate the dimerization. All SOXE members can also heterodimerize in this fashion, whereas SOXE heterodimers with SOX2, SOX4, SOX6 and SOX18 are not supported. We propose a structural model where SOXE-specific intramolecular DIM:HMG interactions are allosterically communicated to the HMG of juxtaposed molecules. Collectively, SOXE factors evolved a unique mode to combinatorially regulate their target genes that relies on a multifaceted interplay between the HMG and DIM domains. This property potentially extends further the diversity of target genes and cell-specific functions that are regulated by SOXE proteins.

  20. Stability and photochemistry of ClO dimers formed at low temperature in the gas phase

    NASA Technical Reports Server (NTRS)

    Cox, R. A.; Hayman, G. D.

    1988-01-01

    The recent observations of elevated concentrations of the ClO radical in the austral spring over Antarctica have implicated catalytic destruction by chlorine in the large depletions seen in the total ozone column. One of the chemical theories consistent with an elevated concentration of the ClO is a cycle involving the formation of the ClO dimer through the association reaction: ClO + ClO = Cl2O2 and the photolysis of the dimer to give the active Cl species necessary for O3 depletion. Here, researchers report experimental studies designed to characterize the dimer of ClO formed by the association reaction at low temperatures. ClO was produced by static photolysis of several different precursor systems: Cl sub 2 + O sub 3; Cl sub 2 O sub 2; OClO + Cl sub 2 O spectroscopy in the U.V. region, which allowed the time dependence of Cl sub 2, Cl sub 2 O, ClO, OClO, O sub 3 and other absorbing molecules to be determined.

  1. CNK and HYP form a discrete dimer by their SAM domains to mediate RAF kinase signaling.

    PubMed

    Rajakulendran, Thanashan; Sahmi, Malha; Kurinov, Igor; Tyers, Mike; Therrien, Marc; Sicheri, Frank

    2008-02-26

    RAF kinase functions in the mitogen-activated protein kinase (MAPK) pathway to transmit growth signals to the downstream kinases MEK and ERK. Activation of RAF catalytic activity is facilitated by a regulatory complex comprising the proteins CNK (Connector enhancer of KSR), HYP (Hyphen), and KSR (Kinase Suppressor of Ras). The sterile alpha-motif (SAM) domain found in both CNK and HYP plays an essential role in complex formation. Here, we have determined the x-ray crystal structure of the SAM domain of CNK in complex with the SAM domain of HYP. The structure reveals a single-junction SAM domain dimer of 1:1 stoichiometry in which the binding mode is a variation of polymeric SAM domain interactions. Through in vitro and in vivo mutational analyses, we show that the specific mode of dimerization revealed by the crystal structure is essential for RAF signaling and facilitates the recruitment of KSR to form the CNK/HYP/KSR regulatory complex. We present two docking-site models to account for how SAM domain dimerization might influence the formation of a higher-order CNK/HYP/KSR complex.

  2. Form, function and functionality of two dimeric toluene-2,4-diisocyanate polymorphs.

    PubMed

    Vella-Zarb, Liana; Dinnebier, Robert E

    2012-04-01

    2,4-Dioxo-1,3-diazetidine-1,3-bis(methyl-m-phenylene) diisocyanate (dimerized toluene-2,4-diisocyanate, TDI) is one of the most widely used aromatic diisocyanates in the polymer industry, and it crystallizes in at least two polymorphic forms (form A and form B) depending on reaction conditions. The crystal structures of the two forms were determined from high-resolution laboratory X-ray powder diffraction data using simulated annealing and Rietveld refinement. In spite of a marked structural similarity between them, significant discrepancies in the physical properties of the two forms prompted analysis of their partitioned energy terms in an effort to better our understanding of the driving force behind such differences in behaviour.

  3. 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.

  4. Association of apolipoprotein E allele {epsilon}4 with late-onset sporadic Alzheimer`s disease

    SciTech Connect

    Lucotte, G.; David, F.; Berriche, S.

    1994-09-15

    Apolipoprotein E, type {epsilon}4 allele (ApoE {epsilon}4), is associated with late-onset sporadic Alzheimer`s disease (AD) in French patients. The association is highly significant (0.45 AD versus 0.12 controls for {epsilon}4 allele frequencies). These data support the involvement of ApoE {epsilon}4 allele as a very important risk factor for the clinical expression of AD. 22 refs., 1 fig., 3 tabs.

  5. [Antirestriction activity of T7 Ocr protein in monomeric and dimeric forms].

    PubMed

    Zavil'gelskiĭ, G B; Kotova, V Iu

    2014-01-01

    The Ocr protein, encoded by 0.3 (ocr) gene of bacteriophage T7, belongs to the family of antirestriction proteins that specifically inhibit the type I restriction-modification systems. Native Ocr forms homodimer (Ocr)2 both in solution and in the crystalline state. The Ocr protein belongs to the family of mimicry proteins. F53D A57E and E53R V77D mutant proteins were obtained, which form monomers. It was shown that the values of the dissociation constants Kd for Ocr, Ocr F53D A57E and Ocr F53RV77D proteins with EcoKI enzyme differ in 1000 times: Kd (Ocr) = 10(-10) M, Kd (Ocr F53D A57E and Ocr F53R V77D) = 10(-7) M. Antimodification activity of the Ocr monomeric forms is significantly reduced. We have shown, that Ocr dimeric form has fundamental importance for high inhibitory activity.

  6. Factor XI Deficiency Protects Against Atherogenesis in Apolipoprotein E/Factor XI Double Knockout Mice.

    PubMed

    Shnerb Ganor, Reut; Harats, Dror; Schiby, Ginette; Gailani, David; Levkovitz, Hanna; Avivi, Camila; Tamarin, Ilia; Shaish, Aviv; Salomon, Ophira

    2016-03-01

    Atherosclerosis and atherothrombosis are still major causes of mortality in the Western world, even after the widespread use of cholesterol-lowering medications. Recently, an association between local thrombin generation and atherosclerotic burden has been reported. Here, we studied the role of factor XI (FXI) deficiency in the process of atherosclerosis in mice. Apolipoprotein E/FXI double knockout mice, created for the first time in our laboratory. There was no difference in cholesterol levels or lipoprotein profiles between apolipoprotein E knockout and double knockout mice. Nevertheless, in 24-week-old double knockout mice, the atherosclerotic lesion area in the aortic sinus was reduced by 32% (P=0.004) in comparison with apolipoprotein E knockout mice. In 42-week-old double knockout mice, FXI deficiency inhibited atherosclerosis progression significantly in the aortic sinus (25% reduction, P=0.024) and in the aortic arch (49% reduction, P=0.028), with a prominent reduction of macrophage infiltration in the atherosclerotic lesions. FXI deprivation was shown to slow down atherogenesis in mice. The results suggest that the development of atherosclerosis can be prevented by targeting FXI. © 2016 American Heart Association, Inc.

  7. Genetically engineered photoinducible homodimerization system with improved dimer-forming efficiency.

    PubMed

    Nihongaki, Yuta; Suzuki, Hideyuki; Kawano, Fuun; Sato, Moritoshi

    2014-03-21

    Vivid (VVD) is a photoreceptor derived from Neurospora Crassa that rapidly forms a homodimer in response to blue light. Although VVD has several advantages over other photoreceptors as photoinducible homodimerization system, VVD has a critical limitation in its low dimer-forming efficiency. To overcome this limitation of wild-type VVD, here we conduct site-directed saturation mutagenesis in the homodimer interface of VVD. We have found that the Ile52Cys mutation of VVD (VVD-52C) substantially improves its homodimer-forming efficiency up to 180%. We have demonstrated the utility of VVD-52C for making a light-inducible gene expression system more robust. In addition, using VVD-52C, we have developed photoactivatable caspase-9, which enables optical control of apoptosis of mammalian cells. The present genetically engineered photoinducible homodimerization system can provide a powerful tool to optically control a broad range of molecular processes in the cell.

  8. The multidrug resistance efflux complex, EmrAB from Escherichia coli forms a dimer in vitro

    SciTech Connect

    Tanabe, Mikio; Szakonyi, Gerda; Brown, Katherine A.; Henderson, Peter J.F.; Nield, Jon; Byrne, Bernadette

    2009-03-06

    Tripartite efflux systems are responsible for the export of toxins across both the inner and outer membranes of Gram negative bacteria. Previous work has indicated that EmrAB-TolC from Escherichia coli is such a tripartite system, comprised of EmrB an MFS transporter, EmrA, a membrane fusion protein and TolC, an outer membrane channel. The whole complex is predicted to form a continuous channel allowing direct export from the cytoplasm to the exterior of the cell. Little is known, however, about the interactions between the individual components of this system. Reconstitution of EmrA + EmrB resulted in co-elution of the two proteins from a gel filtration column indicating formation of the EmrAB complex. Electron microscopic single particle analysis of the reconstituted EmrAB complex revealed the presence of particles approximately 240 x 140 A, likely to correspond to two EmrAB dimers in a back-to-back arrangement, suggesting the dimeric EmrAB form is the physiological state contrasting with the trimeric arrangement of the AcrAB-TolC system.

  9. Effects of the absence of apolipoprotein e on lipoproteins, neurocognitive function, and retinal function.

    PubMed

    Mak, Angel C Y; Pullinger, Clive R; Tang, Ling Fung; Wong, Jinny S; Deo, Rahul C; Schwarz, Jean-Marc; Gugliucci, Alejandro; Movsesyan, Irina; Ishida, Brian Y; Chu, Catherine; Poon, Annie; Kim, Phillip; Stock, Eveline O; Schaefer, Ernst J; Asztalos, Bela F; Castellano, Joseph M; Wyss-Coray, Tony; Duncan, Jacque L; Miller, Bruce L; Kane, John P; Kwok, Pui-Yan; Malloy, Mary J

    2014-10-01

    The identification of a patient with a rare form of severe dysbetalipoproteinemia allowed the study of the consequences of total absence of apolipoprotein E (apoE). To discover the molecular basis of this rare disorder and to determine the effects of complete absence of apoE on neurocognitive and visual function and on lipoprotein metabolism. Whole-exome sequencing was performed on the patient's DNA. He underwent detailed neurological and visual function testing and lipoprotein analysis. Lipoprotein analysis was also performed in the Cardiovascular Research Institute, University of California, San Francisco, on blood samples from the proband's mother, wife, 2 daughters, and normolipidemic control participants. Whole-exome sequencing, lipoprotein analysis, and neurocognitive function. The patient was homozygous for an ablative APOE frameshift mutation (c.291del, p.E97fs). No other mutations likely to contribute to the phenotype were discovered, with the possible exception of two, in ABCC2 (p.I670T) and LIPC (p.G137R). Despite complete absence of apoE, he had normal vision, exhibited normal cognitive, neurological, and retinal function, had normal findings on brain magnetic resonance imaging, and had normal cerebrospinal fluid levels of β-amyloid and tau proteins. He had no significant symptoms of cardiovascular disease except a suggestion of myocardial ischemia on treadmill testing and mild atherosclerosis noted on carotid ultrasonography. He had exceptionally high cholesterol content (760 mg/dL; to convert to millimoles per liter, multiply by 0.0259) and a high cholesterol to triglycerides ratio (1.52) in very low-density lipoproteins with elevated levels of small-diameter high-density lipoproteins, including high levels of prebeta-1 high-density lipoprotein. Intermediate-density lipoproteins, low-density lipoproteins, and very low-density lipoproteins contained elevated apoA-I and apoA-IV levels. The patient's apoC-III and apoC-IV levels were decreased in very

  10. Effects of the Absence of Apolipoprotein E on Lipoproteins, Neurocognitive Function, and Retinal Function

    PubMed Central

    Mak, Angel C. Y.; Pullinger, Clive R.; Tang, Ling Fung; Wong, Jinny S.; Deo, Rahul C.; Schwarz, Jean-Marc; Gugliucci, Alejandro; Movsesyan, Irina; Ishida, Brian Y.; Chu, Catherine; Poon, Annie; Kim, Phillip; Stock, Eveline O.; Schaefer, Ernst J.; Asztalos, Bela F.; Castellano, Joseph M.; Wyss-Coray, Tony; Duncan, Jacque L.; Miller, Bruce L.; Kane, John P.; Kwok, Pui-Yan; Malloy, Mary J.

    2016-01-01

    IMPORTANCE The identification of a patient with a rare form of severe dysbetalipoproteinemia allowed the study of the consequences of total absence of apolipoprotein E (apoE). OBJECTIVES To discover the molecular basis of this rare disorder and to determine the effects of complete absence of apoE on neurocognitive and visual function and on lipoprotein metabolism. DESIGN, SETTING, AND PARTICIPANTS Whole-exome sequencing was performed on the patient’s DNA. He underwent detailed neurological and visual function testing and lipoprotein analysis. Lipoprotein analysis was also performed in the Cardiovascular Research Institute, University of California, San Francisco, on blood samples from the proband’s mother, wife, 2 daughters, and normolipidemic control participants. MAIN OUTCOME MEASURES Whole-exome sequencing, lipoprotein analysis, and neurocognitive function. RESULTS The patient was homozygous for an ablative APOE frameshift mutation (c.291del, p.E97fs). No other mutations likely to contribute to the phenotype were discovered, with the possible exception of two, in ABCC2 (p.I670T) and LIPC (p.G137R). Despite complete absence of apoE, he had normal vision, exhibited normal cognitive, neurological, and retinal function, had normal findings on brain magnetic resonance imaging, and had normal cerebrospinal fluid levels of β-amyloid and tau proteins. He had no significant symptoms of cardiovascular disease except a suggestion of myocardial ischemia on treadmill testing and mild atherosclerosis noted on carotid ultrasonography. He had exceptionally high cholesterol content (760 mg/dL; to convert to millimoles per liter, multiply by 0.0259) and a high cholesterol to triglycerides ratio (1.52) in very low-density lipoproteins with elevated levels of small-diameter high-density lipoproteins, including high levels of prebeta-1 high-density lipoprotein. Intermediate-density lipoproteins, low-density lipoproteins, and very low-density lipoproteins contained elevated apo

  11. Packing Interface Energetics in Different Crystal Forms of the λ Cro Dimer

    PubMed Central

    Ahlstrom, Logan S.; Miyashita, Osamu

    2014-01-01

    Variation among crystal structures of the λ Cro dimer highlights conformational flexibility. The structures range from a wild type closed to a mutant fully open conformation, but it is unclear if each represents a stable solution state or if one may be the result of crystal packing. Here we use molecular dynamics (MD) simulation to investigate the energetics of crystal packing interfaces and the influence of site-directed mutagenesis on them, in order to examine the effect of crystal packing on wild type and mutant Cro dimer conformation. Replica exchange MD of mutant Cro in solution shows that the observed conformational differences between the wild type and mutant protein are not the direct consequence of mutation. Instead, simulation of Cro in different crystal environments reveals that mutation affects the stability of crystal forms. Molecular Mechanics Poisson-Boltzmann Surface Area binding energy calculations reveal the detailed energetics of packing interfaces. Packing interfaces can have diverse properties in strength, energetic components, and some are stronger than the biological dimer interface. Further analysis shows that mutation can strengthen packing interfaces by as much as ~5 kcal/mol in either crystal environment. Thus, in the case of Cro, mutation provides an additional energetic contribution during crystal formation that may stabilize a fully open higher energy state. Moreover, the effect of mutation in the lattice can extend to packing interfaces not involving mutation sites. Our results provide insight into possible models for the effect of crystallization on Cro conformational dynamics and emphasize careful consideration of protein crystal structures. PMID:24218107

  12. Packing interface energetics in different crystal forms of the λ Cro dimer.

    PubMed

    Ahlstrom, Logan S; Miyashita, Osamu

    2014-07-01

    Variation among crystal structures of the λ Cro dimer highlights conformational flexibility. The structures range from a wild type closed to a mutant fully open conformation, but it is unclear if each represents a stable solution state or if one may be the result of crystal packing. Here we use molecular dynamics (MD) simulation to investigate the energetics of crystal packing interfaces and the influence of site-directed mutagenesis on them in order to examine the effect of crystal packing on wild type and mutant Cro dimer conformation. Replica exchange MD of mutant Cro in solution shows that the observed conformational differences between the wild type and mutant protein are not the direct consequence of mutation. Instead, simulation of Cro in different crystal environments reveals that mutation affects the stability of crystal forms. Molecular Mechanics Poisson-Boltzmann Surface Area binding energy calculations reveal the detailed energetics of packing interfaces. Packing interfaces can have diverse properties in strength, energetic components, and some are stronger than the biological dimer interface. Further analysis shows that mutation can strengthen packing interfaces by as much as ∼5 kcal/mol in either crystal environment. Thus, in the case of Cro, mutation provides an additional energetic contribution during crystal formation that may stabilize a fully open higher energy state. Moreover, the effect of mutation in the lattice can extend to packing interfaces not involving mutation sites. Our results provide insight into possible models for the effect of crystallization on Cro conformational dynamics and emphasize careful consideration of protein crystal structures. © 2013 Wiley Periodicals, Inc.

  13. Biochemical, Mutational and In Silico Structural Evidence for a Functional Dimeric Form of the Ornithine Decarboxylase from Entamoeba histolytica

    PubMed Central

    Preeti; Tapas, Satya; Kumar, Pravindra; Madhubala, Rentala; Tomar, Shailly

    2012-01-01

    Background Entamoeba histolytica is responsible for causing amoebiasis. Polyamine biosynthesis pathway enzymes are potential drug targets in parasitic protozoan diseases. The first and rate-limiting step of this pathway is catalyzed by ornithine decarboxylase (ODC). ODC enzyme functions as an obligate dimer. However, partially purified ODC from E. histolytica (EhODC) is reported to exist in a pentameric state. Methodology and Results In present study, the oligomeric state of EhODC was re-investigated. The enzyme was over-expressed in Escherichia coli and purified. Pure protein was used for determination of secondary structure content using circular dichroism spectroscopy. The percentages of α-helix, β-sheets and random coils in EhODC were estimated to be 39%, 25% and 36% respectively. Size-exclusion chromatography and mass spectrophotometry analysis revealed that EhODC enzyme exists in dimeric form. Further, computational model of EhODC dimer was generated. The homodimer contains two separate active sites at the dimer interface with Lys57 and Cys334 residues of opposite monomers contributing to each active site. Molecular dynamic simulations were performed and the dimeric structure was found to be very stable with RMSD value ∼0.327 nm. To gain insight into the functional role, the interface residues critical for dimerization and active site formation were identified and mutated. Mutation of Lys57Ala or Cys334Ala completely abolished enzyme activity. Interestingly, partial restoration of the enzyme activity was observed when inactive Lys57Ala and Cys334Ala mutants were mixed confirming that the dimer is the active form. Furthermore, Gly361Tyr and Lys157Ala mutations at the dimer interface were found to abolish the enzyme activity and destabilize the dimer. Conclusion To our knowledge, this is the first report which demonstrates that EhODC is functional in the dimeric form. These findings and availability of 3D structure model of EhODC dimer opens up

  14. The cyanide hydratase from Neurospora crassa forms a helix which has a dimeric repeat.

    PubMed

    Dent, Kyle C; Weber, Brandon W; Benedik, Michael J; Sewell, B Trevor

    2009-02-01

    The fungal cyanide hydratases form a functionally specialized subset of the nitrilases which catalyze the hydrolysis of cyanide to formamide with high specificity. These hold great promise for the bioremediation of cyanide wastes. The low resolution (3.0 nm) three-dimensional reconstruction of negatively stained recombinant cyanide hydratase fibers from the saprophytic fungus Neurospora crassa by iterative helical real space reconstruction reveals that enzyme fibers display left-handed D(1) S(5.4) symmetry with a helical rise of 1.36 nm. This arrangement differs from previously characterized microbial nitrilases which demonstrate a structure built along similar principles but with a reduced helical twist. The cyanide hydratase assembly is stabilized by two dyadic interactions between dimers across the one-start helical groove. Docking of a homology-derived atomic model into the experimentally determined negative stain envelope suggests the location of charged residues which may form salt bridges and stabilize the helix.

  15. Rigid dimers formed through strong interdigitated H-bonds yield compact 1D supramolecular helical polymers.

    PubMed

    Ciesielski, Artur; Stefankiewicz, Artur R; Hanke, Felix; Persson, Mats; Lehn, Jean-Marie; Samorì, Paolo

    2011-02-07

    Hierarchical self-assembly of small abiotic molecular modules interacting through noncovalent forces is increasingly being used to generate functional structures and materials for electronic, catalytic, and biomedical applications. The greatest control over the geometry in H-bond supramolecular architectures, especially in H-bonded supramolecular polymers, can be achieved by using conformationally rigid molecular modules undergoing self-assembly through strong H-bonds. Their binding strength depends on the multiplicity of the H-bonds, the nature of donor/acceptor pairs and their secondary attractive/repulsive interactions. Here a functionalized molecular module is described, which is capable of self-associating through self-complementary H-bonding patterns comprising four strong and two medium-strength H-bonds to form dimers. The self-association of these phenylpyrimidine-based dimers through directional H-bonding between two lateral pyridin-2(1H)-one units of neighboring molecules allows the formation of highly compact 1D supramolecular polymers by self-assembly on graphite. A concentration-dependent study by scanning tunneling microscopy at the solid-liquid interface, corroborated by dispersion-corrected density functional studies, reveals the controlled generation of either linear supramolecular 2D arrays, or long helical supramolecular polymers with a high shape persistence.

  16. A new bright green-emitting fluorescent protein: Engineered monomeric and dimeric forms

    PubMed Central

    Ilagan, Robielyn P.; Rhoades, Elizabeth; Gruber, David F.; Kao, Hung-Teh; Pieribone, Vincent A.; Regan, Lynne

    2010-01-01

    Summary Fluorescent proteins (FP) have become essential tools in molecular and biological applications. Here, we present a novel fluorescent protein isolated from warm water coral, Cyphastrea microphthalma. The protein, which we named VFP (vivid Verde FP), matures readily at 37 °C and emits bright green light. Further characterizations revealed that VFP has a tendency to form dimers. By creating a homology model of VFP, based on the structure of red fluorescent protein DsRed, we were able to make mutations that alter the protein’s oligomerization state. We present two proteins, mVFP and mVFP1, that are both exclusively monomeric, and one, dVFP, which is dimeric. We characterized the spectroscopic properties of VFP and its variants in comparison with enhance green fluorescent protein (EGFP), a widely use variant of GFP. All the VFP variants are at least twice as bright as EGFP. Finally, we demonstrate the effectiveness of the VFP variants both in vitro and in vivo detection applications. PMID:20345907

  17. The export receptor Crm1 forms a dimer to promote nuclear export of HIV RNA.

    PubMed

    Booth, David S; Cheng, Yifan; Frankel, Alan D

    2014-12-08

    The HIV Rev protein routes viral RNAs containing the Rev Response Element (RRE) through the Crm1 nuclear export pathway to the cytoplasm where viral proteins are expressed and genomic RNA is delivered to assembling virions. The RRE assembles a Rev oligomer that displays nuclear export sequences (NESs) for recognition by the Crm1-Ran(GTP) nuclear receptor complex. Here we provide the first view of an assembled HIV-host nuclear export complex using single-particle electron microscopy. Unexpectedly, Crm1 forms a dimer with an extensive interface that enhances association with Rev-RRE and poises NES binding sites to interact with a Rev oligomer. The interface between Crm1 monomers explains differences between Crm1 orthologs that alter nuclear export and determine cellular tropism for viral replication. The arrangement of the export complex identifies a novel binding surface to possibly target an HIV inhibitor and may point to a broader role for Crm1 dimerization in regulating host gene expression.

  18. Neuropsychiatric symptoms and Apolipoprotein E: Associations with eventual Alzheimer's disease development.

    PubMed

    Burke, Shanna L; Maramaldi, Peter; Cadet, Tamara; Kukull, Walter

    2016-01-01

    Alzheimer's disease (AD) is the result of neurodegeneration, which manifests clinically as deficits in memory, thinking, and behavior. It was hypothesized that neuropsychiatric symptoms and the apolipoprotein E genotype increase the likelihood of Alzheimer's disease development. Utilizing data from the National Alzheimer's Coordinating Center, information from evaluations of 11,453 cognitively intact participants was analyzed. Survival analysis was used to explore relationships between individual neuropsychiatric symptoms as determined by the Neuropsychiatric Inventory Questionnaire, apolipoprotein E, and eventual AD diagnosis. Cox proportional hazard models were utilized to explore the main effects and synergistic (additive and multiplicative) interactions. This study provided evidence for an increased hazard of developing AD among participants with any of the symptoms assessed by the NPI-Q. The hazard of developing AD was almost thirteen times higher for ε4 carriers with delusions and eleven times greater for those with apathy and disinhibition. Statistically significant hazards (p>0.001) were also realized by ε4 carriers with hallucinations; agitation; depression; anxiety; elation; apathy; irritability; and motor, sleep, and appetite disturbances. Findings suggest that neuropsychiatric symptoms are associated with eventual AD diagnosis among a group of cognitively asymptomatic participants at baseline. Many studies begin with a group of participants already impacted by AD diagnosis. The longitudinal analysis of a group of participants who, at baseline, demonstrated no observable signs of AD was a strength of this study. This investigation contributes to the literature exploring an increased hazard of AD due to potential modifiable risk factors and genetic biomarkers such as apolipoprotein E. Copyright © 2016. Published by Elsevier Ireland Ltd.

  19. Neuropsychiatric symptoms and Apolipoprotein E: Associations with eventual Alzheimer’s disease development

    PubMed Central

    Maramaldi, Peter; Cadet, Tamara; Kukull, Walter

    2016-01-01

    Objective Alzheimer’s disease (AD) is the result of neurodegeneration, which manifests clinically as deficits in memory, thinking, and behavior. It was hypothesized that neuropsychiatric symptoms and the apolipoprotein E genotype increase the likelihood of Alzheimer’s disease development. Methods Utilizing data from the National Alzheimer’s Coordinating Center, information from evaluations of 11,453 cognitively intact participants was analyzed. Survival analysis was used to explore relationships between individual neuropsychiatric symptoms as determined by the Neuropsychiatric Inventory Questionnaire, apolipoprotein E, and eventual AD diagnosis. Cox proportional hazard models were utilized to explore the main effects and synergistic (additive and multiplicative) interactions. Results This study provided evidence for an increased hazard of developing AD among participants with any of the symptoms assessed by the NPI-Q. The hazard of developing AD was almost thirteen times higher for ε4 carriers with delusions and eleven times greater for those with apathy and disinhibition. Statistically significant hazards (p > 0.001) were also realized by ε4 carriers with hallucinations; agitation; depression; anxiety; elation; apathy; irritability; and motor, sleep, and appetite disturbances. Conclusions Findings suggest that neuropsychiatric symptoms are associated with eventual AD diagnosis among a group of cognitively asymptomatic participants at baseline. Many studies begin with a group of participants already impacted by AD diagnosis. The longitudinal analysis of a group of participants who, at baseline, demonstrated no observable signs of AD was a strength of this study. This investigation contributes to the literature exploring an increased hazard of AD due to potential modifiable risk factors and genetic biomarkers such as apolipoprotein E. PMID:27111252

  20. Impact of estrogens on atherosclerosis and bone in the apolipoprotein E-deficient mouse model.

    PubMed

    Fernández-Murga, María Leonor; Vinué, Ángela; Caeiro, José Ramón; Guede, David; Tarín, Juan J; Andrés, Vicente; Cano, Antonio

    2015-04-01

    The common inflammatory pathophysiology has nourished the hypothesis of a relationship between osteoporosis and cardiovascular disease. Estrogens are key agents in the modulation of both processes. We investigated whether induction of atherosclerosis affects bone and whether estrogens modulate both processes. Female apolipoprotein E-deficient mice (a well-established model of atherogenesis) were ovariectomized or falsely operated and fed either standard diet or high-fat diet (HFD). Six animals were included in each of the four groups. To clarify mechanisms, we treated preosteoblastic MC3T3-E1 cells with mouse serum. Physiological levels of estrogens in falsely operated mice limited atherosclerotic burden in the thoracic aorta, but not in the aortic arch. Bone resorption, as assessed by C-telopeptides, was increased by ovariectomy in animals fed standard diet, but not in animals fed HFD. Bone microstructural properties at the distal femur showed deteriorated trabecular architecture in bone volumetric fraction and trabecular number after ovariectomy, but trabecular pattern factor, trabecular thickness, trabecular spacing, or the structural model index remained unchanged. Changes in cortical parameters were not significant. Volumetric bone mineral density was reduced in trabecular bone, but not in cortical bone, in ovariectomized mice fed standard diet. Preosteoblastic MC3T3-E1 cells exhibited increased cellular proliferation and viability and alkaline phosphatase activity after treatment with sera from animals fed HFD. Endogenous estrogens partially reduce atherogenic burden in female apolipoprotein E-deficient mice. Ovariectomy increases bone resorption, but not under exacerbated proatherogenic conditions induced by HFD. The absence of apolipoprotein E might have an influence on the asymmetric responses of atherogenesis and bone resorption.

  1. Structure, Aggregation, and Activity of a Covalent Insulin Dimer Formed During Storage of Neutral Formulation of Human Insulin.

    PubMed

    Hjorth, Christian Fogt; Norrman, Mathias; Wahlund, Per-Olof; Benie, Andrew J; Petersen, Bent O; Jessen, Christian M; Pedersen, Thomas Å; Vestergaard, Kirsten; Steensgaard, Dorte B; Pedersen, Jan Skov; Naver, Helle; Hubálek, František; Poulsen, Christian; Otzen, Daniel

    2016-04-01

    A specific covalently linked dimeric species of insulin high molecular weight products (HMWPs), formed during prolonged incubation of a neutral pharmaceutical formulation of human insulin, were characterized in terms of tertiary structure, self-association, biological activity, and fibrillation properties. The dimer was formed by a covalent link between A21Asn and B29Lys. It was analyzed using static and dynamic light scattering and small-angle X-ray scattering to evaluate its self-association behavior. The tertiary structure was obtained using nuclear magnetic resonance and X-ray crystallography. The biological activity of HMWP was determined using 2 in vitro assays, and its influence on fibrillation was investigated using Thioflavin T assays. The dimer's tertiary structure was nearly identical to that of the noncovalent insulin dimer, and it was able to form hexamers in the presence of zinc. The dimer exhibited reduced propensity for self-association in the absence of zinc but significantly postponed the onset of fibrillation in insulin formulations. Consistent with its dimeric state, the tested species of HMWP showed little to no biological activity in the used assays. This study is the first detailed characterization of a specific type of human insulin HMWP formed during storage of a marketed pharmaceutical formulation. These results indicate that this specific type of HMWP is unlikely to antagonize the physical stability of the formulation, as HMWP retained a tertiary structure similar to the noncovalent dimer and participated in hexamer assembly in the presence of zinc. In addition, increasing amounts of HMWP reduce the rate of insulin fibrillation.

  2. Analysis of cell surface alterations in Legionella pneumophila cells treated with human apolipoprotein E.

    PubMed

    Palusinska-Szysz, Marta; Zdybicka-Barabas, Agnieszka; Cytryńska, Małgorzata; Wdowiak-Wróbel, Sylwia; Chmiel, Elżbieta; Gruszecki, Wiesław I

    2015-03-01

    Binding of human apolipoprotein E (apoE) to Legionella pneumophila lipopolysaccharide was analysed at the molecular level by Fourier-transform infrared spectroscopy, thereby providing biophysical evidence for apoE-L. pneumophila lipopolysaccharide interaction. Atomic force microscopy imaging of apoE-exposed L. pneumophila cells revealed alterations in the bacterial cell surface topography and nanomechanical properties in comparison with control bacteria. The changes induced by apoE binding to lipopolysaccharide on the surface of L. pneumophila cells may participate in: (1) impeding the penetration of host cells by the bacteria; (2) suppression of pathogen intracellular growth and eventually; and (3) inhibition of the development of infection.

  3. Application of denaturing gradient gel electrophoresis to detect DNA sequence differences encoding apolipoprotein E isoforms

    SciTech Connect

    Parker, S.; Angelico, M.C.; Laffel, L.; Krolewski, A.S. Harvard Medical School, Boston, MA )

    1993-04-01

    Apolipoprotein E (apoE) plays an important role in plasma lipid metabolism. Three common isoforms of this protein have been identified by the isoelectric focusing method. In this report the authors describe a new method for distinguishing these isoforms. Their method employs PCR amplification of the DNA sequence of exon 4 in the apoE gene followed by denaturing gradient gel electrophoresis (DGGE) to distinguish its different melting characteristics. Identification of the ApoE isoforms through DNA melting behavior rather than protein charge differences eliminates the problems associated with isoelectric focusing and facilitates screening for additional mutations at the apoE locus. 12 refs., 2 figs.

  4. Vitamin D Binding Protein Isoforms and Apolipoprotein E in Cerebrospinal Fluid as Prognostic Biomarkers of Multiple Sclerosis

    PubMed Central

    Lis, Katarzyna; Minari, Nicoletta; Falvo, Sara; Marnetto, Fabiana; Caldano, Marzia; Reviglione, Raffaella; Berchialla, Paola; Capobianco, Marco A.; Malentacchi, Maria; Corpillo, Davide; Bertolotto, Antonio

    2015-01-01

    Background Multiple sclerosis (MS) is a multifactorial autoimmune disease of the central nervous system with a heterogeneous and unpredictable course. To date there are no prognostic biomarkers even if they would be extremely useful for early patient intervention with personalized therapies. In this context, the analysis of inter-individual differences in cerebrospinal fluid (CSF) proteome may lead to the discovery of biological markers that are able to distinguish the various clinical forms at diagnosis. Methods To this aim, a two dimensional electrophoresis (2-DE) study was carried out on individual CSF samples from 24 untreated women who underwent lumbar puncture (LP) for suspected MS. The patients were clinically monitored for 5 years and then classified according to the degree of disease aggressiveness and the disease-modifying therapies prescribed during follow up. Results The hierarchical cluster analysis of 2-DE dataset revealed three protein spots which were identified by means of mass spectrometry as Apolipoprotein E (ApoE) and two isoforms of vitamin D binding protein (DBP). These three protein spots enabled us to subdivide the patients into subgroups correlated with clinical classification (MS aggressive forms identification: 80%). In particular, we observed an opposite trend of values for the two protein spots corresponding to different DBP isoforms suggesting a role of a post-translational modification rather than the total protein content in patient categorization. Conclusions These findings proved to be very interesting and innovative and may be developed as new candidate prognostic biomarkers of MS aggressiveness, if confirmed. PMID:26046356

  5. Euglena gracilis ascorbate peroxidase forms an intramolecular dimeric structure: its unique molecular characterization.

    PubMed

    Ishikawa, Takahiro; Tajima, Naoko; Nishikawa, Hitoshi; Gao, Yongshun; Rapolu, Madhusudhan; Shibata, Hitoshi; Sawa, Yoshihiro; Shigeoka, Shigeru

    2010-02-09

    Euglena gracilis lacks a catalase and contains a single APX (ascorbate peroxidase) and enzymes related to the redox cycle of ascorbate in the cytosol. In the present study, a full-length cDNA clone encoding the Euglena APX was isolated and found to contain an open reading frame encoding a protein of 649 amino acids with a calculated molecular mass of 70.5 kDa. Interestingly, the enzyme consisted of two entirely homologous catalytic domains, designated APX-N and APX-C, and an 102 amino acid extension in the N-terminal region, which had a typical class II signal proposed for plastid targeting in Euglena. A computer-assisted analysis indicated a novel protein structure with an intramolecular dimeric structure. The analysis of cell fractionation showed that the APX protein is distributed in the cytosol, but not the plastids, suggesting that Euglena APX becomes mature in the cytosol after processing of the precursor. The kinetics of the recombinant mature FL (full-length)-APX and the APX-N and APX-C domains with ascorbate and H2O2 were almost the same as that of the native enzyme. However, the substrate specificity of the mature FL-APX and the native enzyme was different from that of APX-N and APX-C. The mature FL-APX, but not the truncated forms, could reduce alkyl hydroperoxides, suggesting that the dimeric structure is correlated with substrate recognition. In Euglena cells transfected with double-stranded RNA, the silencing of APX expression resulted in a significant increase in the cellular level of H2O2, indicating the physiological importance of APX to the metabolism of H2O2.

  6. A rapid flat gel isoelectric focusing method for the determination of apolipoprotein E phenotypes and its application.

    PubMed

    Eto, M; Watanabe, K; Ishii, K

    1985-06-30

    A rapid flat gel isoelectric focusing method has been developed for the determination of apolipoprotein E phenotypes. Isoelectric focusing in 5% polyacrylamide flat gel with 8 mol/l urea and 2.8% pharmalyte (pH 4-6.5) was carried out at 3,000 V and 4 degrees C for 1 h under a constant power of 30 W. The separation of apolipoprotein E isoproteins was good and the isoelectric points were determined. Using this method, the apolipoprotein E phenotype frequency was examined in the Japanese population, and a higher frequency of phenotype E3/3 and a lower frequency of phenotype E3/2 were found in Japanese than those reported for the German, American or English population. In our focusing system the cut-off point of apolipoprotein E2/E3 ratio between the phenotype E3/3 and E3/2 was assumed to be approximately 0.9. These results indicate that this method may be useful for the determination of apolipoprotein E phenotypes.

  7. Tor forms a dimer through an N-terminal helical solenoid with a complex topology.

    PubMed

    Baretić, Domagoj; Berndt, Alex; Ohashi, Yohei; Johnson, Christopher M; Williams, Roger L

    2016-04-13

    The target of rapamycin (Tor) is a Ser/Thr protein kinase that regulates a range of anabolic and catabolic processes. Tor is present in two complexes, TORC1 and TORC2, in which the Tor-Lst8 heterodimer forms a common sub-complex. We have determined the cryo-electron microscopy (EM) structure of Tor bound to Lst8. Two Tor-Lst8 heterodimers assemble further into a dyad-symmetry dimer mediated by Tor-Tor interactions. The first 1,300 residues of Tor form a HEAT repeat-containing α-solenoid with four distinct segments: a highly curved 800-residue N-terminal 'spiral', followed by a 400-residue low-curvature 'bridge' and an extended 'railing' running along the bridge leading to the 'cap' that links to FAT region. This complex topology was verified by domain insertions and offers a new interpretation of the mTORC1 structure. The spiral of one TOR interacts with the bridge of another, which together form a joint platform for the Regulatory Associated Protein of TOR (RAPTOR) regulatory subunit.

  8. Tor forms a dimer through an N-terminal helical solenoid with a complex topology

    NASA Astrophysics Data System (ADS)

    Baretić, Domagoj; Berndt, Alex; Ohashi, Yohei; Johnson, Christopher M.; Williams, Roger L.

    2016-04-01

    The target of rapamycin (Tor) is a Ser/Thr protein kinase that regulates a range of anabolic and catabolic processes. Tor is present in two complexes, TORC1 and TORC2, in which the Tor-Lst8 heterodimer forms a common sub-complex. We have determined the cryo-electron microscopy (EM) structure of Tor bound to Lst8. Two Tor-Lst8 heterodimers assemble further into a dyad-symmetry dimer mediated by Tor-Tor interactions. The first 1,300 residues of Tor form a HEAT repeat-containing α-solenoid with four distinct segments: a highly curved 800-residue N-terminal 'spiral', followed by a 400-residue low-curvature 'bridge' and an extended `railing' running along the bridge leading to the 'cap' that links to FAT region. This complex topology was verified by domain insertions and offers a new interpretation of the mTORC1 structure. The spiral of one TOR interacts with the bridge of another, which together form a joint platform for the Regulatory Associated Protein of TOR (RAPTOR) regulatory subunit.

  9. Docosahexaenoic acid prevents cognitive deficits in human apolipoprotein E epsilon 4-targeted replacement mice.

    PubMed

    Chouinard-Watkins, Raphaël; Vandal, Milène; Léveillé, Pauline; Pinçon, Anthony; Calon, Frédéric; Plourde, Mélanie

    2017-09-01

    At a population level, dietary consumption of fish rich in docosahexaenoic acid (DHA) is associated with prevention of cognitive decline but this association is not clear in carriers of the apolipoprotein E epsilon 4 allele (E4). Plasma and liver DHA concentrations show significant alterations in E4 carriers, in part corrected by DHA supplementation. However, whether DHA sufficiency in E4 carriers has consequences on cognition is unknown. Mice expressing human E4 or apolipoprotein E epsilon 3 allele (E3) were fed either a control diet or a diet containing DHA for 8 months and cognitive performance was tested using the object recognition test and the Barnes maze test. In E4 mice fed the control diet, impaired memory was detected and arachidonic acid concentrations were elevated in the hippocampus compared to E3 mice fed the control diet. DHA consumption prevented memory decline and restored arachidonic acid concentrations in the hippocampus of E4 mice. Our results suggest that long-term high-dose DHA intake may prevent cognitive decline in E4 carriers. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. 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.

  11. Pallidal neuronal apolipoprotein E in pantothenate kinase-associated neurodegeneration recapitulates ischemic injury to the globuspallidus

    PubMed Central

    Woltjer, Randall L.; Reese, Lindsay C.; Richardson, Brian E.; Tran, Huong; Green, Sarah; Pham, Thao; Chalupsky, Megan; Gabriel, Isabella; Light, Tyler; Sanford, Lynn; Jeong, Suh Y.; Hamada, Jeffrey; Schwanemann, Leila K.; Rogers, Caleb; Gregory, Allison; Hogarth, Penelope; Hayflick, Susan J.

    2015-01-01

    Pantothenate kinase-associated neurodegeneration (PKAN) is a progressive movement disorder that is due to mutations in PANK2. Pathologically, it is a member of a class of diseases known as neurodegeneration with brain iron accumulation (NBIA) and features increased tissue iron and ubiquitinated protein aceous aggregates in the globuspallidus. We have previously determined that these aggregates represent condensed residue derived from degenerated pallidal neurons. However, the protein content, other than ubiquitin, of these aggregates remains unknown. In the present study, we performed biochemical and immunohistochemical studies to characterize these aggregates and found them to be enriched in apolipoprotein E that is poorly soluble in detergent solutions. However, did not determine a significant association between APOE genotype and the clinical phenotype of disease in our database of 81 cases. Rather, we frequently identified similar ubiquitin- and apolipoprotein E-enriched lesions in these neurons in non-PKAN patients in the penumbrae of remote infarcts that involve the globuspallidus, and occasionally in other brain sites that contain large γ-aminobutyric acid (GABA)ergic neurons. Our findings, taken together, suggest that tissue or cellular hypoxic/ischemic injury within the globuspallidus may underlie the pathogenesis of PKAN. PMID:26547561

  12. Dietary carnosine prevents early atherosclerotic lesion formation in apolipoprotein E-null mice.

    PubMed

    Barski, Oleg A; Xie, Zhengzhi; Baba, Shahid P; Sithu, Srinivas D; Agarwal, Abhinav; Cai, Jian; Bhatnagar, Aruni; Srivastava, Sanjay

    2013-06-01

    Atherosclerotic lesions are associated with the accumulation of reactive aldehydes derived from oxidized lipids. Although inhibition of aldehyde metabolism has been shown to exacerbate atherosclerosis and enhance the accumulation of aldehyde-modified proteins in atherosclerotic plaques, no therapeutic interventions have been devised to prevent aldehyde accumulation in atherosclerotic lesions. We examined the efficacy of carnosine, a naturally occurring β-alanyl-histidine dipeptide, in preventing aldehyde toxicity and atherogenesis in apolipoprotein E-null mice. In vitro, carnosine reacted rapidly with lipid peroxidation-derived unsaturated aldehydes. Gas chromatography mass-spectrometry analysis showed that carnosine inhibits the formation of free aldehydes 4-hydroxynonenal and malonaldialdehyde in Cu(2+)-oxidized low-density lipoprotein. Preloading bone marrow-derived macrophages with cell-permeable carnosine analogs reduced 4-hydroxynonenal-induced apoptosis. Oral supplementation with octyl-D-carnosine decreased atherosclerotic lesion formation in aortic valves of apolipoprotein E-null mice and attenuated the accumulation of protein-acrolein, protein-4-hydroxyhexenal, and protein-4-hydroxynonenal adducts in atherosclerotic lesions, whereas urinary excretion of aldehydes as carnosine conjugates was increased. The results of this study suggest that carnosine inhibits atherogenesis by facilitating aldehyde removal from atherosclerotic lesions. Endogenous levels of carnosine may be important determinants of atherosclerotic lesion formation, and treatment with carnosine or related peptides could be a useful therapy for the prevention or the treatment of atherosclerosis.

  13. FAD286, an aldosterone synthase inhibitor, reduced atherosclerosis and inflammation in apolipoprotein E-deficient mice.

    PubMed

    Gamliel-Lazarovich, Aviva; Gantman, Anna; Coleman, Raymond; Jeng, Arco Y; Kaplan, Marielle; Keidar, Shlomo

    2010-09-01

    Aldosterone is known to be involved in atherosclerosis and cardiovascular disease and blockade of its receptor was shown to improve cardiovascular function. It was, therefore, hypothesized that inhibition of aldosterone synthesis would also reduce atherosclerosis development. To test this hypothesis, we examined the effect of FAD286 (FAD), an aldosterone synthase inhibitor, on the development of atherosclerosis in spontaneous atherosclerotic apolipoprotein E-deficient mice. Mice were divided into three treatment groups: normal diet, low-salt diet (LSD) and LSD treated with FAD at 30 mg/kg per day (LSD + FAD) for 10 weeks. Histomorphometry of the aortas obtained from these mice showed that atherosclerotic lesion area increased by three-fold under LSD compared with normal diet and FAD significantly reduced lesion area to values similar to normal diet. Changes in atherosclerosis were paralleled by changes in the expression of the inflammation markers (C-reactive protein, monocyte chemotactic protein-1, interleukin-6, nuclear factor kappa B and intercellular adhesion molecule-1) in peritoneal macrophages obtained from these mice. Surprisingly, whereas LSD increased serum or urine aldosterone levels, FAD did not alter these levels when evaluated at the end of the study. In J774A.1 macrophage-like cell line stimulated with lipopolysaccharide, FAD was shown to have a direct dose-dependent anti-inflammatory effect. In apolipoprotein E-deficient mice, FAD reduces atherosclerosis and inflammation. However, these actions appeared to be dissociated from its effect on inhibition of aldosterone synthesis.

  14. [Relationship between apolipoprotein E polymorphism and cognitive function in patients with primary hypertension].

    PubMed

    Su, Yanling; Chen, Xiaoping; Huang, Yan; Jiang, Lingyun; Huang, He

    2009-08-01

    To explore the relationship between apolipoprotein E polymorphism and cognitive function in primary hypertension patients, we collected 200 Chinese primary hypertensive patients. Blood pressure (BP), heart rate (HR), height, body weight, waistline, hip circumference were measured. The Mini Mental State Examination (MMSE) was applied to test the cognitive function and compute score. Full-automatic bio-chemistry analyzer was used to determine total cholesterol (TC) and triglyeride (TG) and fasting glucose. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RELP) was used for the analysis of the apolipoprotein E polymorphism. We found that in primary hypertension patients, the genotype frequency of epsilon3/4 and epsilon4/4 were significantly higher in the cognitive impairment group than that in the cognitive normal group. The allele frequency of e4 is obviously higher in the cognitive impairment group than that in the cognitive normal group. Age and epsilon4/4 genetype were positively correlated with hypertensive-cognitive impairment, while cultural level was negtively correlated with it. ApoEepsilon4 allele and age might be risk factors for the cognitive impairment in hypertensive patients. The epsilon4 homozygote (epsilon4/4) might be an important influencing factor for the progression of cognitive impairment.

  15. Brain-targeted delivery of resveratrol using solid lipid nanoparticles functionalized with apolipoprotein E.

    PubMed

    Neves, Ana Rute; Queiroz, Joana Fontes; Reis, Salette

    2016-04-09

    The present study takes advantage of the beneficial effects of resveratrol as a neuroprotective compound. Resveratrol-loaded solid lipid nanoparticles were functionalized with apolipoprotein E which can be recognized by the LDL receptors overexpressed on the blood-brain barrier. Transmission electron microscopy images revealed spherical nanoparticles, dynamic light scattering gave a Z-average lower than 200 nm, and a zeta potential of around -13 mV and very high resveratrol entrapment efficiency (ca. 90 %). In vitro cytotoxic effects were assessed by MTT and LDH assays in hCMEC/D3 cell line and revealed no toxicity up to 50 μM over 4 h of incubation. The permeability through hCMEC/D3 monolayers showed a significant increase (1.8-fold higher) for resveratrol-loaded solid lipid nanoparticles functionalized with apolipoprotein E when compared to non-functionalized ones. In conclusion, these nanosystems might be a promising strategy for resveratrol delivery into the brain, while protecting it from degradation in the blood stream. Graphical abstract .

  16. Altered Energy Metabolism Pathways in the Posterior Cingulate in Young Adult Apolipoprotein E ɛ4 Carriers

    PubMed Central

    Perkins, Michelle; Wolf, Andrew B.; Chavira, Bernardo; Shonebarger, Daniel; Meckel, J.P.; Leung, Lana; Ballina, Lauren; Ly, Sarah; Saini, Aman; Jones, T. Bucky; Vallejo, Johana; Jentarra, Garilyn; Valla, Jon

    2016-01-01

    The APOE gene, encoding apolipoprotein E, is the primary genetic risk factor for late-onset Alzheimer’s disease (AD). Apolipoprotein E ɛ4 allele (APOE4) carriers have alterations in brain structure and function (as measured by brain imaging) even as young adults. Examination of this population is valuable in further identifying details of these functional changes and their association with vulnerability to AD decades later. Previous work demonstrates functional declines in mitochondrial activity in the posterior cingulate cortex, a key region in the default mode network, which appears to be strongly associated with functional changes relevant to AD risk. Here, we demonstrate alterations in the pathways underlying glucose, ketone, and mitochondrial energy metabolism. Young adult APOE4 carriers displayed upregulation of specific glucose (GLUT1 & GLUT3) and monocarboxylate (MCT2) transporters, the glucose metabolism enzyme hexokinase, the SCOT & AACS enzymes involved in ketone metabolism, and complexes I, II, and IV of the mitochondrial electron transport chain. The monocarboxylate transporter (MCT4) was found to be downregulated in APOE4 carriers. These data suggest that widespread dysregulation of energy metabolism in this at-risk population, even decades before possible disease onset. Therefore, these findings support the idea that alterations in brain energy metabolism may contribute significantly to the risk that APOE4 confers for AD. PMID:27128370

  17. Structural and biochemical studies on Vibrio cholerae Hsp31 reveals a novel dimeric form and Glutathione-independent Glyoxalase activity

    PubMed Central

    Dey, Sanjay

    2017-01-01

    Vibrio cholerae experiences a highly hostile environment at human intestine which triggers the induction of various heat shock genes. The hchA gene product of V. cholerae O395, referred to a hypothetical intracellular protease/amidase VcHsp31, is one such stress-inducible homodimeric protein. Our current study demonstrates that VcHsp31 is endowed with molecular chaperone, amidopeptidase and robust methylglyoxalase activities. Through site directed mutagenesis coupled with biochemical assays on VcHsp31, we have confirmed the role of residues in the vicinity of the active site towards amidopeptidase and methylglyoxalase activities. VcHsp31 suppresses the aggregation of insulin in vitro in a dose dependent manner. Through crystal structures of VcHsp31 and its mutants, grown at various temperatures, we demonstrate that VcHsp31 acquires two (Type-I and Type-II) dimeric forms. Type-I dimer is similar to EcHsp31 where two VcHsp31 monomers associate in eclipsed manner through several intersubunit hydrogen bonds involving their P-domains. Type-II dimer is a novel dimeric organization, where some of the intersubunit hydrogen bonds are abrogated and each monomer swings out in the opposite directions centering at their P-domains, like twisting of wet cloth. Normal mode analysis (NMA) of Type-I dimer shows similar movement of the individual monomers. Upon swinging, a dimeric surface of ~400Å2, mostly hydrophobic in nature, is uncovered which might bind partially unfolded protein substrates. We propose that, in solution, VcHsp31 remains as an equilibrium mixture of both the dimers. With increase in temperature, transformation to Type-II form having more exposed hydrophobic surface, occurs progressively accounting for the temperature dependent increase of chaperone activity of VcHsp31. PMID:28235098

  18. Amphiphile dependency of the monomeric and dimeric forms of acetylcholinesterase from human erythrocyte membrane.

    PubMed

    Ott, P; Brodbeck, U

    1984-08-08

    Human erythrocyte membrane-bound acetylcholinesterase was converted to a monomeric species by treatment of ghosts with 2-mercaptoethanol and iodoacetic acid. After solubilization with Triton X-100, the reduced and alkylated enzyme was partially purified by affinity chromatography and separated from residual dimeric enzyme by sucrose density gradient centrifugation in a zonal rotor. Monomeric and dimeric acetylcholinesterase showed full enzymatic activity in presence of Triton X-100 whereas in the absence of detergent, activity was decreased to approx. 20% and 15%, respectively. Preformed egg phosphatidylcholine vesicles fully sustained activity of the monomeric species whereas the dimer was only 80% active. The results suggest that a dimeric structure is not required for manifestation of amphiphile dependency of membrane-bound acetylcholinesterase from human erythrocytes. Furthermore, monomeric enzyme appears to be more easily inserted into phospholipid bilayers than the dimeric species.

  19. Syndecan 4 is involved in mediating HCV entry through interaction with lipoviral particle-associated apolipoprotein E.

    PubMed

    Lefèvre, Mathieu; Felmlee, Daniel J; Parnot, Marie; Baumert, Thomas F; Schuster, Catherine

    2014-01-01

    Hepatitis C virus (HCV) is a major cause of liver disease worldwide and HCV infection represents a major health problem. HCV associates with host lipoproteins forming host/viral hybrid complexes termed lipoviral particles. Apolipoprotein E (apoE) is a lipoprotein component that interacts with heparan sulfate proteoglycans (HSPG) to mediate hepatic lipoprotein uptake, and may likewise mediate HCV entry. We sought to define the functional regions of apoE with an aim to identify critical apoE binding partners involved in HCV infection. Using adenoviral vectors and siRNA to modulate apoE expression we show a direct correlation of apoE expression and HCV infectivity, whereas no correlation exists with viral protein expression. Mutating the HSPG binding domain (HSPG-BD) of apoE revealed key residues that are critical for mediating HCV infection. Furthermore, a novel synthetic peptide that mimics apoE's HSPG-BD directly and competitively inhibits HCV infection. Genetic knockdown of the HSPG proteins syndecan (SDC) 1 and 4 revealed that SDC4 principally mediates HCV entry. Our data demonstrate that HCV uses apoE-SDC4 interactions to enter hepatoma cells and establish infection. Targeting apoE-SDC interactions could be an alternative strategy for blocking HCV entry, a critical step in maintaining chronic HCV infection.

  20. An ABCA1-independent pathway for recycling a poorly lipidated 8.1 nm apolipoprotein E particle from glia

    PubMed Central

    Fan, Jianjia; Stukas, Sophie; Wong, Charmaine; Chan, Jennifer; May, Sharon; DeValle, Nicole; Hirsch-Reinshagen, Veronica; Wilkinson, Anna; Oda, Michael N.; Wellington, Cheryl L.

    2011-01-01

    Lipid transport in the brain is coordinated by glial-derived lipoproteins that contain apolipoprotein E (apoE) as their primary protein. Here we show that apoE is secreted from wild-type (WT) primary murine mixed glia as nascent lipoprotein subspecies ranging from 7.5 to 17 nm in diameter. Negative-staining electron microscropy (EM) revealed rouleaux, suggesting a discoidal structure. Potassium bromide (KBr) density gradient ultracentrifugation showed that all subspecies, except an 8.1 nm particle, were lipidated. Glia lacking the cholesterol transporter ABCA1 secreted only 8.1 nm particles, which were poorly lipidated and nondiscoidal but could accept lipids to form the full repertoire of WT apoE particles. Receptor-associated-protein (RAP)-mediated inhibition of apoE receptor function blocked appearance of the 8.1 nm species, suggesting that this particle may arise through apoE recycling. Selective deletion of the LDL receptor (LDLR) reduced the level of 8.1 nm particle production by approximately 90%, suggesting that apoE is preferentially recycled through the LDLR. Finally, apoA-I stimulated secretion of 8.1 nm particles in a dose-dependent manner. These results suggest that nascent glial apoE lipoproteins are secreted through multiple pathways and that a greater understanding of these mechanisms may be relevant to several neurological disorders. PMID:21705806

  1. Syndecan 4 Is Involved in Mediating HCV Entry through Interaction with Lipoviral Particle-Associated Apolipoprotein E

    PubMed Central

    Lefèvre, Mathieu; Felmlee, Daniel J.; Parnot, Marie; Baumert, Thomas F.; Schuster, Catherine

    2014-01-01

    Hepatitis C virus (HCV) is a major cause of liver disease worldwide and HCV infection represents a major health problem. HCV associates with host lipoproteins forming host/viral hybrid complexes termed lipoviral particles. Apolipoprotein E (apoE) is a lipoprotein component that interacts with heparan sulfate proteoglycans (HSPG) to mediate hepatic lipoprotein uptake, and may likewise mediate HCV entry. We sought to define the functional regions of apoE with an aim to identify critical apoE binding partners involved in HCV infection. Using adenoviral vectors and siRNA to modulate apoE expression we show a direct correlation of apoE expression and HCV infectivity, whereas no correlation exists with viral protein expression. Mutating the HSPG binding domain (HSPG-BD) of apoE revealed key residues that are critical for mediating HCV infection. Furthermore, a novel synthetic peptide that mimics apoE’s HSPG-BD directly and competitively inhibits HCV infection. Genetic knockdown of the HSPG proteins syndecan (SDC) 1 and 4 revealed that SDC4 principally mediates HCV entry. Our data demonstrate that HCV uses apoE-SDC4 interactions to enter hepatoma cells and establish infection. Targeting apoE-SDC interactions could be an alternative strategy for blocking HCV entry, a critical step in maintaining chronic HCV infection. PMID:24751902

  2. High levels of homocysteine downregulate apolipoprotein E expression via nuclear factor kappa B

    PubMed Central

    Trusca, Violeta G; Mihai, Adina D; Fuior, Elena V; Fenyo, Ioana M; Gafencu, Anca V

    2016-01-01

    AIM: To investigate the effect of high homocysteine (Hcy) levels on apolipoprotein E (apoE) expression and the signaling pathways involved in this gene regulation. METHODS: Reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot were used to assess apoE expression in cells treated with various concentrations (50-500 μmol/L) of Hcy. Calcium phosphate-transient transfections were performed in HEK-293 and RAW 264.7 cells to evaluate the effect of Hcy on apoE regulatory elements [promoter and distal multienhancer 2 (ME2)]. To this aim, plasmids containing the proximal apoE promoter [(-500/+73)apoE construct] alone or in the presence of ME2 [ME2/(-500/+73)apoE construct] to drive the expression of the reporter luciferase gene were used. Co-transfection experiments were carried out to investigate the downstream effectors of Hcy-mediated regulation of apoE promoter by using specific inhibitors or a dominant negative form of IKβ. In other co-transfections, the luciferase reporter was under the control of synthetic promoters containing multiple specific binding sites for nuclear factor kappa B (NF-κB), activator protein-1 (AP-1) or nuclear factor of activated T cells (NFAT). Chromatin immunoprecipitation (ChIP) assay was accomplished to detect the binding of NF-κB p65 subunit to the apoE promoter in HEK-293 treated with 500 μmol/L Hcy. As control, cells were incubated with similar concentration of cysteine. NF-κB p65 proteins bound to DNA were immunoprecipitated with anti-p65 antibodies and DNA was identified by PCR using primers amplifying the region -100/+4 of the apoE gene. RESULTS: RT-PCR revealed that high levels of Hcy (250-750 μmol/L) induced a 2-3 fold decrease in apoE mRNA levels in HEK-293 cells, while apoE gene expression was not significantly affected by treatment with lower concentrations of Hcy (100 μmol/L). Immunoblotting data provided additional evidence for the negative role of Hcy in apoE expression. Hcy decreased apoE promoter

  3. No association between apolipoprotein E or N-acetyltransferase 2 gene polymorphisms and age-related hearing loss.

    PubMed

    Dawes, Piers; Platt, Hazel; Horan, Michael; Ollier, William; Munro, Kevin; Pendleton, Neil; Payton, Antony

    2015-01-01

    Age-related hearing loss has a genetic component, but there have been limited genetic studies in this field. Both N-acetyltransferase 2 and apolipoprotein E genes have previously been associated. However, these studies have either used small sample sizes, examined a limited number of polymorphisms, or have produced conflicting results. Here we use a haplotype tagging approach to determine association with age-related hearing loss and investigate epistasis between these two genes. Candidate gene association study of a continuous phenotype. We investigated haplotype tagging single nucleotide polymorphisms in the N-acetyltransferase 2 gene and the presence/absence of the apolipoprotein E ε4 allele for association with age-related hearing loss in a cohort of 265 Caucasian elderly volunteers from Greater Manchester, United Kingdom. Hearing phenotypes were generated using principal component analysis of the hearing threshold levels for the better ear (severity, slope, and concavity). Genotype data for the N-acetyltransferase 2 gene was obtained from existing genome-wide association study data from the Illumina 610-Quadv1 chip. Apolipoprotein E genotyping was performed using Sequenom technology. Linear regression analysis was performed using Plink and Stata software. No significant associations (P value, > 0.05) were observed between the N-acetyltransferase 2 or apolipoprotein E gene polymorphisms and any hearing factor. No significant association was observed for epistasis analysis of apolipoprotein E ε4 and the N-acetyltransferase 2 single nucleotide polymorphism rs1799930 (NAT2*6A). We found no evidence to support that either N-acetyltransferase 2 or apolipoprotein E gene polymorphisms are associated with age-related hearing loss in a cohort of 265 elderly volunteers. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

  4. No association between apolipoprotein E or N‐Acetyltransferase 2 gene polymorphisms and age‐related hearing loss

    PubMed Central

    Dawes, Piers; Platt, Hazel; Horan, Michael; Ollier, William; Munro, Kevin; Pendleton, Neil

    2014-01-01

    Objectives/Hypothesis Age‐related hearing loss has a genetic component, but there have been limited genetic studies in this field. Both N‐acetyltransferase 2 and apolipoprotein E genes have previously been associated. However, these studies have either used small sample sizes, examined a limited number of polymorphisms, or have produced conflicting results. Here we use a haplotype tagging approach to determine association with age‐related hearing loss and investigate epistasis between these two genes. Study Design Candidate gene association study of a continuous phenotype. Methods We investigated haplotype tagging single nucleotide polymorphisms in the N‐acetyltransferase 2 gene and the presence/absence of the apolipoprotein E ε4 allele for association with age‐related hearing loss in a cohort of 265 Caucasian elderly volunteers from Greater Manchester, United Kingdom. Hearing phenotypes were generated using principal component analysis of the hearing threshold levels for the better ear (severity, slope, and concavity). Genotype data for the N‐acetyltransferase 2 gene was obtained from existing genome‐wide association study data from the Illumina 610‐Quadv1 chip. Apolipoprotein E genotyping was performed using Sequenom technology. Linear regression analysis was performed using Plink and Stata software. Results No significant associations (P value, > 0.05) were observed between the N‐acetyltransferase 2 or apolipoprotein E gene polymorphisms and any hearing factor. No significant association was observed for epistasis analysis of apolipoprotein E ε4 and the N‐acetyltransferase 2 single nucleotide polymorphism rs1799930 (NAT2*6A). Conclusion We found no evidence to support that either N‐acetyltransferase 2 or apolipoprotein E gene polymorphisms are associated with age‐related hearing loss in a cohort of 265 elderly volunteers. Level of Evidence N/A. Laryngoscope, 125:E33–E38, 2015 PMID:25155015

  5. Apolipoprotein E4 influences growth and cognitive responses to micronutrient supplementation in shantytown children from northeast Brazil

    PubMed Central

    Mitter, Sumeet S.; Oriá, Reinaldo B.; Kvalsund, Michelle P.; Pamplona, Paula; Joventino, Emanuella Silva; Mota, Rosa M. S.; Gonçalves, Davi C.; Patrick, Peter D.; Guerrant, Richard L.; Lima, Aldo A. M.

    2012-01-01

    OBJECTIVE: Apolipoprotein E4 may benefit children during early periods of life when the body is challenged by infection and nutritional decline. We examined whether apolipoprotein E4 affects intestinal barrier function, thereby improving short-term growth and long-term cognitive outcomes in Brazilian shantytown children. METHODS: A total of 213 Brazilian shantytown children with below-median height-for-age z-scores (HAZ) received 200,000 IU of retinol (every four months), zinc (40 mg twice weekly), or both for one year, with half of each group receiving glutamine supplementation for 10 days. Height-for-age z-scores, weight-for-age z-scores, weight-for-height z-scores, and lactulose:mannitol ratios were assessed during the initial four months of treatment. An average of four years (range 1.4-6.6) later, the children underwent cognitive testing to evaluate non-verbal intelligence, coding, verbal fluency, verbal learning, and delayed verbal learning. Apolipoprotein E4 carriage was determined by PCR analysis for 144 children. RESULTS: Thirty-seven children were apolipoprotein E4(+), with an allele frequency of 13.9%. Significant associations were found for vitamin A and glutamine with intestinal barrier function. Apolipoprotein E4(+) children receiving glutamine presented significant positive Pearson correlations between the change in height-for-age z-scores over four months and delayed verbal learning, along with correlated changes over the same period in weight-for-age z-scores and weight-for-height z-scores associated with non-verbal intelligence quotients. There was a significant correlation between vitamin A supplementation of apolipoprotein E4(+) children and improved delta lactulose/mannitol. Apolipoprotein E4(-) children, regardless of intervention, exhibited negative Pearson correlations between the change in lactulose-to-mannitol ratio over four months and verbal learning and non-verbal intelligence. CONCLUSIONS: During development, apolipoprotein E4 may

  6. Monocytic elastase-mediated apolipoprotein-E degradation: Potential involvement of microglial elastase-like proteases in apolipoprotein-E proteolysis in brains with Alzheimers disease.

    PubMed

    Suenaga, Midori; Furuta, Akiko; Wakabayashi, Koichi; Saibara, Toshiji; Matsunaga, Yoichi

    2015-08-01

    Impaired clearance of soluble Aβ (amyloid-β) promotes Aβ aggregation in brains with Alzheimer's disease (AD), while apolipoprotein-E (ApoE) in microglia mediates Aβ clearance. We studied the protease responsible for ApoE(4) degradation in human peripheral monocyte extracts, which are from the same lineage as microglia. We detected the hydrolytic activity for ApoE(4) in high-salt extracts with 2 M NaCl and found that the activity was inhibited by a serine protease inhibitor and an elastase-specific inhibitor, but not by other protease inhibitors. The extracts exhibited higher activity for the elastase substrate, and we followed the activity with ion-exchange and gel-filtration chromatography. Through silver staining, we partially purified a protein of 28 kDa, which was clarified as elastase by liquid chromatography-tandem mass spectrometry. These observations suggest that elastase is the key protease for ApoE(4) degradation. We also detected ApoE(4) hydrolytic activity in high-salt extracts in mouse microglial (BV-2) cell lysates, and showed that the ApoE(4) fragments by the BV-2 extracts differed from the fragments by the monocyte extracts. Though the ApoE(4) degradation by the extracts was not inhibited with elastase-specific inhibitors, it was inhibited by an elastase-specific monoclonal antibody, suggesting that elastase-like proteases in microglia differ from those of monocytes. Immunohistochemistry revealed that both elastase and ApoE were expressed in the senile plaques of brains with AD. In vitro studies also disclosed the localization of elastase in the microglial cell line, BV-2. Our results suggest that elastase-like proteases in the microglial cells surrounding Aβ plaques are responsible for ApoE degradation in the brain.

  7. Apolipoprotein E, gender, and Alzheimer's disease: an overlooked, but potent and promising interaction.

    PubMed

    Ungar, Leo; Altmann, Andre; Greicius, Michael D

    2014-06-01

    Alzheimer's disease (AD) is an increasingly prevalent, fatal neurodegenerative disease that has proven resistant, thus far, to all attempts to prevent it, forestall it, or slow its progression. The ε4 allele of the Apolipoprotein E gene (APOE4) is a potent genetic risk factor for sporadic and late-onset familial AD. While the link between APOE4 and AD is strong, many expected effects, like increasing the risk of conversion from MCI to AD, have not been widely replicable. One critical, and commonly overlooked, feature of the APOE4 link to AD is that several lines of evidence suggest it is far more pronounced in women than in men. Here we review previous literature on the APOE4 by gender interaction with a particular focus on imaging-related studies.

  8. [Apolipoprotein E (APOE) gene polymorphism and risk and prognosis in cerebral amyloid angiopathy-related haemorrhage].

    PubMed

    Mendel, Tadeusz; Gromadzka, Grażyna

    2010-01-01

    The authors present current opinions about the role of APOE (apolipoprotein E gene) genotype as a factor modifying risk, course and prognosis in haemorrhagic stroke of cerebral amyloid origin. The search for the role of genetics in haemorrhagic stroke has been ongoing for more than 15 years. One of the most frequently investigated genotypes in the context of intracerebral haemorrhages is the APOE genotype. Alleles APOE e2 and e4 have been established as risk factors for cerebral amyloid angiopathy (CAA), as well as for cerebral amyloid angiopathy-related haemorrhage (CAAH). Moreover, APOE genotype seems to determine prognosis in CAAH in terms of early mortality, as well as risk of recurrence. Current findings related to the association between different isoforms of apoE and haemorrhagic stroke due to CAA do not allow us to formulate any clinical recommendations yet.

  9. The role of apolipoprotein E in Guillain-Barré syndrome and experimental autoimmune neuritis.

    PubMed

    Zhang, Hong-liang; Wu, Jiang; Zhu, Jie

    2010-01-01

    Apolipoprotein E (apoE) is a 34.2 kDa glycosylated protein characterized by its wide tissue distribution and multiple functions. ApoE has been widely studied in lipid metabolism, cardiocerebrovascular diseases, and neurodegenerative diseases like Alzheimer's disease and mild cognitive impairment, and so forth. Recently, a growing body of evidence has pointed to nonlipid related properties of apoE, including suppression of T cell proliferation, regulation of macrophage function, facilitation of lipid antigen presentation by CD1 molecules to natural killer T (NKT) cells, and modulation of inflammation and oxidation. By these properties, apoE impacts physiology and pathophysiology at multiple levels. The present paper summarizes updated studies on the immunoregulatory function of apoE, with special focus on isoform-specific effects of apoE on Guillain-Barré syndrome (GBS) and its animal model experimental autoimmune neuritis (EAN).

  10. The Role of Apolipoprotein E in Guillain-Barré Syndrome and Experimental Autoimmune Neuritis

    PubMed Central

    Zhang, Hong-liang; Wu, Jiang; Zhu, Jie

    2010-01-01

    Apolipoprotein E (apoE) is a 34.2 kDa glycosylated protein characterized by its wide tissue distribution and multiple functions. ApoE has been widely studied in lipid metabolism, cardiocerebrovascular diseases, and neurodegenerative diseases like Alzheimer's disease and mild cognitive impairment, and so forth. Recently, a growing body of evidence has pointed to nonlipid related properties of apoE, including suppression of T cell proliferation, regulation of macrophage function, facilitation of lipid antigen presentation by CD1 molecules to natural killer T (NKT) cells, and modulation of inflammation and oxidation. By these properties, apoE impacts physiology and pathophysiology at multiple levels. The present paper summarizes updated studies on the immunoregulatory function of apoE, with special focus on isoform-specific effects of apoE on Guillain-Barré syndrome (GBS) and its animal model experimental autoimmune neuritis (EAN). PMID:20182542

  11. Method for the Simultaneous Quantitation of Apolipoprotein E Isoforms using Tandem Mass Spectrometry

    PubMed Central

    Wildsmith, Kristin R.; Han, Bomie; Bateman, Randall J.

    2009-01-01

    Using Apolipoprotein E (ApoE) as a model protein, we developed a protein isoform analysis method utilizing Stable Isotope Labeling Tandem Mass Spectrometry (SILT MS). ApoE isoforms are quantitated using the intensities of the b and y ions of the 13C-labeled tryptic isoform-specific peptides versus unlabeled tryptic isoform-specific peptides. The ApoE protein isoform analysis using SILT allows for the simultaneous detection and relative quantitation of different ApoE isoforms from the same sample. This method provides a less biased assessment of ApoE isoforms compared to antibody-dependent methods, and may lead to a better understanding of the biological differences between isoforms. PMID:19653990

  12. Longitudinal study of cerebrospinal fluid amyloid proteins and apolipoprotein E in patients with probable Alzheimer's disease.

    PubMed

    Pirttilä, T; Koivisto, K; Mehta, P D; Reinikainen, K; Kim, K S; Kilkku, O; Heinonen, E; Soininen, H; Riekkinen, P; Wisniewski, H M

    1998-06-12

    Levels of soluble amyloid beta protein (sAbeta), amyloid beta precursor protein (APP) and apolipoprotein E (apoE) were examined in cerebrospinal fluid (CSF) obtained twice, at baseline and after 3-year follow-up, from 25 patients with probable Alzheimer's disease (AD). Levels of sAbeta and apoE from patients with the apoE4 allele decreased with time, whereas the levels were similar in patients without apoE4 allele. Changes of sAbeta and apoE concentrations correlated significantly with those of mini-mental state examination (MMSE) scores. Levels of sAbeta did not change with time in patients with mild dementia, whereas they decreased significantly in patients with moderate dementia. ApoE concentrations decreased in both groups whereas APP levels were similar. We conclude that measurements of CSF sAbeta and apoE levels may be helpful in monitoring progression of the disease.

  13. Inflammation, cytokines, immune response, apolipoprotein E, cholesterol, and oxidative stress in Alzheimer disease: therapeutic implications.

    PubMed

    Candore, Giuseppina; Bulati, Matteo; Caruso, Calogero; Castiglia, Laura; Colonna-Romano, Giuseppina; Di Bona, Danilo; Duro, Giovanni; Lio, Domenico; Matranga, Domenica; Pellicanò, Mariavaleria; Rizzo, Claudia; Scapagnini, Giovanni; Vasto, Sonya

    2010-01-01

    Alzheimer disease (AD) is a heterogeneous and progressive neurodegenerative disease, which in Western society mainly accounts for senile dementia. Today many countries have rising aging populations and are facing an increased prevalence of age-related diseases, such as AD, with increasing health-care costs. Understanding the pathophysiology process of AD plays a prominent role in new strategies for extending the health of the elderly population. Considering the future epidemic of AD, prevention and treatment are important goals of ongoing research. However, a better understanding of AD pathophysiology must be accomplished to make this objective feasible. In this paper, we review some hot topics concerning AD pathophysiology that have an important impact on therapeutic perspectives. Hence, we have focused our attention on inflammation, cytokines, immune response, apolipoprotein E (APOE), cholesterol, oxidative stress, as well as exploring the related therapeutic possibilities, i.e., nonsteroidal antiinflammatory drugs, cytokine blocking antibodies, immunotherapy, diet, and curcumin.

  14. Apolipoprotein E alleles in Alzheimer`s and Parkinson`s patients

    SciTech Connect

    Poduslo, S.E.; Schwankhaus, J.D.

    1994-09-01

    A number of investigators have found an association between the apolipoprotein E4 allele and Alzheimer`s disease. The E4 allele appears at a higher frequency in late onset familial Alzheimer`s patients. In our studies we obtained blood samples from early and late onset familial and sporadic Alzheimer`s patients and spouses, as well as from Parkinson`s patients. The patients were diagnosed as probable Alzheimer`s patients after a neurological examination, extensive blood work, and a CAT scan. The diagnosis was made according to the NINCDS-ADRDA criteria. The apolipoprotein E4 polymorphism was detected after PCR amplification of genomic DNA, restriction enzyme digestion with Hhal, and polyacrylamide gel electrophoresis. Ethidium bromide-stained bands at 91 bp were designated as allele 3, at 83 bp as allele 2, and at 72 bp as allele 4. Of the 84 probable Alzheimer`s patients (all of whom were Caucasian), 47 were heterozygous and 13 were homozygous for the E4 allele. There were 26 early onset patients; 13 were heterozygous and 7 homozygous for the E4 allele. The frequencies for the E4 allele for late onset familial patients was 0.45 and for sporadic patients was 0.37. We analyzed 77 spouses with an average age of 71.9 {plus_minus} 7.4 years as controls, and 15 were heterozygous for the E4 allele for an E4 frequency of 0.097. Of the 53 Parkinson`s patients, 11 had the E4 allele for a frequency of 0.113. Thus our findings support the association of the ApoE4 allele with Alzheimer`s disease.

  15. Bowman-Birk protease inhibitor from the seeds of Vigna unguiculata forms a highly stable dimeric structure.

    PubMed

    Rao, K N; Suresh, C G

    2007-10-01

    Different protease inhibitors including Bowman-Birk type (BBI) have been reported from the seeds of Vigna unguiculata. Protease isoinhibitors of double-headed Bowman-Birk type from the seeds of Vigna unguiculata have been purified and characterized. The BBI from Vigna unguiculata (Vu-BBI) has been found to undergo self-association to form very stable dimers and more complex oligomers, by size-exclusion chromatography and SDS-PAGE in the presence of urea. Many BBIs have been reported to undergo self-association to form homodimers or more complex oligomers in solution. Only one dimeric crystal structure of a BBI (pea-BBI) is reported to date. We report the three-dimensional structure of a Vu-BBI determined at 2.5 A resolution. Although, the inhibitor has a monomer fold similar to that found in other known structures of Bowman-Birk protease inhibitors, its quaternary structure is different from that commonly observed in this family. The structural elements responsible for the stability of monomer molecule and dimeric association are discussed. The Vu-BBI may use dimeric or higher quaternary association to maintain the physiological state and to execute its biological function.

  16. Scavenger receptor function of mouse Fcγ receptor III contributes to progression of atherosclerosis in apolipoprotein E hyperlipidemic mice.

    PubMed

    Zhu, Xinmei; Ng, Hang Pong; Lai, Yen-Chun; Craigo, Jodi K; Nagilla, Pruthvi S; Raghani, Pooja; Nagarajan, Shanmugam

    2014-09-01

    Recent studies showed loss of CD36 or scavenger receptor-AI/II (SR-A) does not ameliorate atherosclerosis in a hyperlipidemic mouse model, suggesting receptors other than CD36 and SR-A may also contribute to atherosclerosis. In this report, we show that apolipoprotein E (apoE)-CD16 double knockout (DKO; apoE-CD16 DKO) mice have reduced atherosclerotic lesions compared with apoE knockout mice. In vivo and in vitro foam cell analyses showed apoE-CD16 DKO macrophages accumulated less neutral lipids. Reduced foam cell formation in apoE-CD16 DKO mice is not due to change in expression of CD36, SR-A, and LOX-1. This led to a hypothesis that CD16 may have scavenger receptor activity. We presented evidence that a soluble form of recombinant mouse CD16 (sCD16) bound to malondialdehyde-modified low-density lipoprotein (MDALDL), and this binding is blocked by molar excess of MDA- modified BSA and anti-MDA mAbs, suggesting CD16 specifically recognizes MDA epitopes. Interestingly, sCD16 inhibited MDALDL binding to macrophage cell line, as well as soluble forms of recombinant mouse CD36, SR-A, and LOX-1, indicating CD16 can cross-block MDALDL binding to other scavenger receptors. Anti-CD16 mAb inhibited immune complex binding to sCD16, whereas it partially inhibited MDALDL binding to sCD16, suggesting MDALDL binding site may be in close proximity to the immune complex binding site in CD16. Loss of CD16 expression resulted in reduced levels of MDALDL-induced proinflammatory cytokine expression. Finally, CD16-deficient macrophages showed reduced MDALDL-induced Syk phosphorylation. Collectively, our findings suggest scavenger receptor activity of CD16 may, in part, contribute to the progression of atherosclerosis.

  17. Recombinant neural protein PrP can bind with both recombinant and native apolipoprotein E in vitro.

    PubMed

    Gao, Chen; Lei, Yan-Jun; Han, Jun; Shi, Qi; Chen, Lan; Guo, Yan; Gao, Yong-Jun; Chen, Jian-Ming; Jiang, Hui-Ying; Zhou, Wei; Dong, Xiao-Ping

    2006-09-01

    The most essential and crucial step during the pathogenesis of transmissible spongiform encephalopathy is the conformational change of cellular prion protein (PrP(C)) to pathologic isoform (PrP(Sc)). A lot of data revealed that caveolae-like domains (CLDs) in the cell surface were the probable place where the conversion of PrP proteins happened. Apolipoprotein E (ApoE) is an apolipoprotein which is considered to play an important role in the development of Alzheimer's disease and other neurodegenerative diseases by forming protein complex through binding to the receptor located in the clathrin-coated pits of the cell surface. In this study, a 914-bp cDNA sequence encoding human ApoE3 was amplified from neuroblastoma cell line SH-SY5Y. Three human ApoE isomers were expressed and purified from Escherichia coli. ApoE-specific antiserum was prepared by immunizing rabbits with the purified ApoE3. GST/His pull-down assay, immunoprecipitation and ELISA revealed that three full-length ApoE isomers interact with the recombinant full-length PrP protein in vitro. The regions corresponding to protein binding were mapped in the N-terminal segment of ApoE (amino acid 1-194) and the N-terminal of PrP (amino acid 23-90). Moreover, the recombinant PrP showed the ability to form a complex with the native ApoE from liver tissues. Our data provided direct evidence of molecular interaction between ApoE and PrP. It also supplied scientific clues for assessing the significance of CLDs on the surface of cellular membrane in the process of conformational conversion from PrP(C) to PrP(Sc) and probing into the pathogenesis of transmissible spongiform encephalopathy.

  18. The dimers of cyanamide

    NASA Astrophysics Data System (ADS)

    Moffat, J. B.

    Ab initio calculations have been performed on various dimeric forms of cyanamide. The "nondissociative" dimerization of cyanamide leads to cyclic molecules all of which are unstable with respect to cyanamide. However, the molecules produced by "dissociative" dimerization are stable relative to cyanamide. Dicyandiamide is found to be the most stable of nine dimeric configurations.

  19. Evidence for major gene inheritance of Alzheimer disease in families of patients with and without Apolipoprotein E {epsilon}4

    SciTech Connect

    Rao, V.S.; Auerbach, S.A.; Farrer, L.A.

    1996-09-01

    Apolipoprotein E (APOE) genotype is the single most important determinant to the common form of Alzheimer disease (AD) yet identified. Several studies show that family history of AD is not entirely accounted for by APOE genotype. Also, there is evidence for an interaction between APOE genotype and gender. We carried out a complex segregation analysis in 636 nuclear families of consecutively ascertained and rigorously diagnosed probands in the Multi-Institutional Research in Alzheimer Genetic Epidemiology study in order to derive models of disease transmission which account for the influences of APOE genotype of the proband and gender. In the total group of families, models postulating sporadic occurrence, no major gene effect, random environmental transmission, and Mendelian inheritance were rejected. Transmission of AD in families of probands with at least one {epsilon}4 allele best fit a dominant model. Moreover, single gene inheritance best explained clustering of the disorder in families of probands lacking E4, but a more complex genetic model or multiple genetic models may ultimately account for risk in this group of families. Our results also suggest that susceptibility to AD differs between men and women regardless of the proband`s APOE status. Assuming a dominant model, AD appears to be completely penetrant in women, whereas only 62%-65% of men with predisposing genotypes develop AD. However, parameter estimates from the arbitrary major gene model suggests that AD is expressed dominantly in women and additively in men. These observations, taken together with epidemiologic data, are consistent with the hypothesis of an interaction between genes and other biological factors affecting disease susceptibility. 76 refs., 4 tabs.

  20. Amyloid-β42 Alters Apolipoprotein E Solubility in Brains of Mice with Five Familial AD Mutations

    PubMed Central

    Youmans, Katherine Lynn; Leung, Steffi; Zhang, Juan; Maus, Erika; Baysac, Kathleen; Bu, Guojun; Vassar, Robert; Yu, Chunjiang; LaDu, Mary Jo

    2011-01-01

    Amyloid plaques composed of the 42 amino acid form of amyloid-beta peptide (Aβ42) are a pathological hallmark of Alzheimer’s disease (AD), but soluble and intraneuronal Aβ42 are the more proximal causes of synaptic dysfunction and neurotoxicity. Apolipoprotein E (apoE) modulates this disease process, as inheritance of the ε4 allele of the apoE gene is the primary genetic risk factor for AD. To address the solubility of Aβ42 and apoE, a protein extraction protocol in the presence of minimal to extensive Aβ42 pathology was optimized. Sequential extractions with TBS, TBS+Triton X-100 (TBSX), and guanidine-HCl (GuHCl) or formic acid (FA) were used with tissue from young and old wild type or mice expressing 5 familial AD mutations (5xFAD), in disease-susceptible or –resistant brain regions. In older 5xFAD mice, the extraction of insoluble Aβ42 and m-apoE protein was increased with FA compared to GuHCl. The 5 FAD mutations significantly increase production of Aβ42, recapitulating AD-like pathology at a greatly accelerated rate. Consistent protein extraction and the specificity of extractions for soluble or membrane-associated proteins were demonstrated. Age-dependent increases in Aβ42 were observed in all extraction fractions, particularly in the cortex and hippocampus. In both young and old 5xFAD mice, Aβ42 is TBS- or GuHCl-soluble. While in WT mice m-apoE is TBSX-soluble, in 5xFAD mice m-apoE is TBS- or GuHCl-soluble. Thus, the extraction profile of Aβ42 paralleled that of m-apoE in 5xFAD mice. As now characterized, this method identifies the extraction profile for disease-relevant brain proteins, both normal or modified due to neuropathological processes. PMID:21219931

  1. Role of apolipoprotein E polymorphism as a prognostic marker in traumatic brain injury and neurodegenerative disease: a critical review.

    PubMed

    Maiti, Tanmoy Kumar; Konar, Subhas; Bir, Shyamal; Kalakoti, Piyush; Bollam, Papireddy; Nanda, Anil

    2015-11-01

    OBJECT The difference in course and outcome of several neurodegenerative conditions and traumatic injuries of the nervous system points toward a possible role of genetic and environmental factors as prognostic markers. Apolipoprotein E (Apo-E), a key player in lipid metabolism, is recognized as one of the most powerful genetic risk factors for dementia and other neurodegenerative diseases. In this article, the current understanding of APOE polymorphism in various neurological disorders is discussed. METHODS The English literature was searched for various studies describing the role of APOE polymorphism as a prognostic marker in neurodegenerative diseases and traumatic brain injury. The wide ethnic distribution of APOE polymorphism was discussed, and the recent meta-analyses of role of APOE polymorphism in multiple diseases were analyzed and summarized in tabular form. RESULTS Results from the review of literature revealed that the distribution of APOE is varied in different ethnic populations. APOE polymorphism plays a significant role in pathogenesis of neurodegeneration, particularly in Alzheimer's disease. APOE ε4 is considered a marker for poor prognosis in various diseases, but APOE ε2 rather than APOE ε4 has been associated with cerebral amyloid angiopathy-related bleeding and sporadic Parkinson's disease. The role of APOE polymorphism in various neurological diseases has not been conclusively elucidated. CONCLUSIONS Apo-E is a biomarker for various neurological and systemic diseases. Therefore, while analyzing the role of APOE polymorphism in neurological diseases, the interpretation should be done after adjusting all the confounding factors. A continuous quest to look for associations with various neurological diseases and wide knowledge of available literature are required to improve the understanding of the role of APOE polymorphism in these conditions and identify potential therapeutic targets.

  2. Impact of the apolipoprotein E polymorphism, age and sex on neurogenesis in mice: pathophysiological relevance for Alzheimer's disease?

    PubMed

    Koutseff, Alexis; Mittelhaeuser, Christophe; Essabri, Karim; Auwerx, Johan; Meziane, Hamid

    2014-01-13

    Apolipoprotein E (ApoE) is found in three different forms in humans (ApoE2, ApoE3 and ApoE4), and ApoE polymorphism is recognized as a major risk factor for Alzheimer's disease (AD). ApoE is involved in lipid and cholesterol transport, cell repair, and amyloid-β deposition and certain studies suggest potential implications in neurogenesis. In this regard, we investigated the possible impact of the three different human ApoE isoforms on neurogenesis. We used ApoE knock-in mice of different ages and sex, and quantified newborn cells in the hippocampus by flow cytometry. Young adult ApoE4 mice (10-12 week-old) from both sexes displayed reduced neurogenesis compared with wild-types and the other genotypes. In addition, young adult ApoE2 female mice showed improved hippocampal progenitor cell proliferation. In older mice (1 year), hippocampal neurogenesis was globally decreased, particularly in females, and the difference between ApoE4 and the other genotypes observed in young animals disappeared for the two sexes, except for aged ApoE3 females. Indeed, a surprising protective effect of the ApoE3 genotype was observed in aged females. Our study highlights the role of ApoE in neurogenesis, and shows for the first time an early inequality between the ApoE genotypes. The reduced neurogenesis observed for the ApoE4 genotype and the improved results obtained in young ApoE2 females support the idea of a difference in the balance between neuronal birth and death modulated by the ApoE polymorphism in young animals. The maintenance of this balance and its modulation can influence pathophysiological mechanisms predisposing to neurodegenerative diseases like AD. © 2013 Elsevier B.V. All rights reserved.

  3. Patterns formed on the dimer vacancy array of Si(100) by self-assembly

    NASA Astrophysics Data System (ADS)

    Liu, H. W.; Yang, H. Q.; Guo, H. M.; Wang, Y. L.; Lin, X.; Pang, S. J.; Gao, H. J.

    2002-12-01

    The self-assembly of Si on the dimer vacancy array (DVA) is studied. Factors, such as the amount of deposition, substrate temperature and annealing temperature, which affect the self-assembly processes are discussed. The formation mechanism of the DVA is discussed.

  4. The apolipoprotein E/CI/CII gene cluster and late-onset Alzheimer disease

    SciTech Connect

    Yu, Chang-En; Nemens, E.; Olson, J.M.; Goddard, K.A.B.; Kukull, W.A.; Payami, H.; Boehnke, M.; Wijsman, E.M.; Orr, H.T.; White, J.A.

    1994-04-01

    The chromosome 19 apolipoprotein E/CI/CII gene cluster was examined for evidence of linkage to a familial Alzheimer disease (FAD) locus. The family groups studied were Volga German (VG), early-onset non-VG (ENVG; mean age at onset <60 years), and late-onset families. A genetic association was observed between apolipoprotein E (ApoE) allele E4 and FAD in late-onset families; the E4 allele frequency was .51 in affected subjects, .37 in at-risk subjects, .11 in spouses, and .19 in unrelated controls. The differences between the E4 frequencies in affected subjects versus controls and in at-risk subjects versus controls were highly significant. No association between the E4 allele and FAD was observed in the ENVG or VG groups. A statistically significant allelic association between E4 and AD was also observed in a group of unrelated subjects; the E4 frequency was .26 in affected subjects, versus .19 in controls (Z[sub SND] = 2.20, P < .03). Evidence of linkage of ApoE and ApoCII to FAD was examined by maximum-likelihood methods, using three models and assuming autosomal dominant inheritance: (1) age-dependent penetrance, (2) extremely low (1%) penetrance, and (3) age-dependent penetrance corrected for sporadic Alzheimer disease (AD). For ApoCII in late-onset families, results for close linkage were negative, and only small positive lod-score-statistic (Z) values were obtained. For ApoE in late-onset kindreds, positive Z values were obtained when either allele frequencies from controls or allele frequencies from the families were used. When linkage disequilibrium was incorporated into the analysis, the Z values increased. For the ENVG group, results for ApoE and ApoCII were uniformly negative. Affected-pedigree-member analysis gave significant results for the late-onset kindreds, for ApoE, when control allele frequencies were used but not when allele frequencies were derived from the families. 58 refs., 6 tabs.

  5. The Apolipoprotein E/CI/CII Gene Cluster and Late-Onset Alzheimer Disease

    PubMed Central

    Yu, Chang-En; Payami, Haydeh; Olson, Jane M.; Boehnke, Michael; Wijsman, Ellen M.; Orr, Harry T.; Kukull, Walter A.; Goddard, Katrina A. B.; Nemens, Ellen; White, June A.; Alonso, M. Elisa; Taylor, Todd D.; Ball, Melvyn J.; Kaye, Jeffrey; Morris, John; Chui, Helena; Sadovnick, Adele D.; Martin, George M.; Larson, Eric B.; Heston, Leonard L.; Bird, Thomas D.; Schellenberg, Gerard D.

    1994-01-01

    The chromosome 19 apolipoprotein E/CI/CII gene cluster was examined for evidence of linkage to a familial Alzheimer disease (FAD) locus. The family groups studied were Volga German (VG), early-onset non-VG (ENVG; mean age at onset <60 years), and late-onset families. A genetic association was observed between apolipoprotein E (ApoE) allele ε4 and FAD in late-onset families; the ε4 allele frequency was .51 in affected subjects, .37 in at-risk subjects, .11 in spouses, and .19 in unrelated controls. The differences between the ε4 frequencies in affected subjects versus controls and in at-risk subjects versus controls were highly significant (standard normal deviate [ZSND]) = 7.37, P < 10−9; and ZSND = 4.07, P < .00005, respectively). No association between the ε4 allele and FAD was observed in the ENVG or VG groups. A statistically significant allelic association between ε4 and AD was also observed in a group of unrelated subjects; the ε4 frequency was .26 in affected subjects, versus .19 in controls (ZSND = 2.20, P < .03). Evidence of linkage of ApoE and ApoCII to FAD was examined by maximum-likelihood methods, using three models and assuming autosomal dominant inheritance: (1) age-dependent penetrance, (2) extremely low (1%) penetrance, and (3) age-dependent penetrance corrected for sporadic Alzheimer disease (AD). For ApoCII in late-onset families, results for close linkage were negative, and only small positive lod-score-statistic (Z) values were obtained (model 1, maximum Z [Zmax] = 0.61, recombination fraction [θ] = .30; model 2, Zmax = 0.47, θ = .20). For ApoE in late-onset kindreds, positive Z values were obtained when either allele frequencies from controls (model 1, Zmax = 2.02, θ = .15; model 2, Zmax = 3.42, θ = .05) or allele frequencies from the families (model 1, Zmax = 1.43, θ = .15; model 2, Zmax = 1.70, θ = .05) were used. When linkage disequilibrium was incorporated into the analysis, the Z values increased (model 1, Zmax = 3.17,

  6. Electrochemical, spectral, and computational studies of metalloporphyrin dimers formed by cation complexation of crown ether cavities.

    PubMed

    Chitta, Raghu; Rogers, Lisa M; Wanklyn, Amber; Karr, Paul A; Kahol, Pawan K; Zandler, Melvin E; D'Souza, Francis

    2004-11-01

    The effect on the electrochemical oxidation and reduction potentials of 5,10,15,20-tetrakis(benzo-15-crown-5)porphyrin (TCP) and its metal derivatives (MTCP; M = Mg(II), VO(IV), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Ag(II)) upon potassium ion induced dimerization of the porphyrins was systematically performed in benzonitrile containing 0.1 M (TBA)ClO(4) by differential pulse voltammetry technique. The HOMO--LUMO energy level diagram constructed from the electrochemical data revealed destabilization of the HOMO level and stabilization of the LUMO level upon dimer formation while such a perturbation was larger for the HOMO level than the LUMO level. The geometry and electronic structure of a representative ZnTCP and its dimer, K(4)(ZnTCP)(2), were evaluated by the ab initio B3LYP method utilizing a mixed basis set of 3-21G(*) for Zn, K, O, and N and STO-3G for C and H. The inter-porphyrin ring distance of the dimer calculated from the optimized geometry agreed with the spectroscopically determined one, and the calculated HOMO and LUMO frontier orbitals revealed delocalization on both of the porphyrins rings. The metal-metal distances calculated from the triplet ESR spectra of the K(+) induced porphyrin dimers bearing paramagnetic metal ions in the cavity followed the trend Cu--Cu < VO--VO < Ag--Ag. However, the spectral shifts resulting from the exciton coupling of the interacting porphyrin pi-systems revealed no specific trend with respect to the metal ion in the porphyrin cavity. Additionally, linear trends in the electrochemically measured HOMO--LUMO gap and the energy corresponding to the most intense visible band of both MTCP and K(4)(MTCP)(2) were observed. A reduced HOMO--LUMO gap predicted for the dimer by B3LYP/(3-21G(), STO-3G) calculations was confirmed by the results of optical absorption and electrochemical studies.

  7. Cytosolic BNIP3 Dimer Interacts with Mitochondrial BAX Forming Heterodimers in the Mitochondrial Outer Membrane under Basal Conditions.

    PubMed

    Hendgen-Cotta, Ulrike B; Esfeld, Sonja; Rudi, Katharina; Miinalainen, Ilkka; Klare, Johann P; Rassaf, Tienush

    2017-03-23

    The primary function of mitochondria is energy production, a task of particular importance especially for cells with a high energy demand like cardiomyocytes. The B-cell lymphoma (BCL-2) family member BCL-2 adenovirus E1B 19 kDa-interacting protein 3 (BNIP3) is linked to mitochondrial targeting after homodimerization, where it functions in inner membrane depolarization and permeabilization of the mitochondrial outer membrane (MOM) mediating cell death. We investigated the basal distribution of cardiac BNIP3 in vivo and its physical interaction with the pro-death protein BCL2 associated X, apoptosis regulator (BAX) and with mitochondria using immunoblot analysis, co-immunoprecipitation, and continuous wave and pulsed electron paramagnetic resonance spectroscopy techniques. We found that BNIP3 is present as a dimer in the cytosol and in the outer membrane of cardiac mitochondria under basal conditions. It forms disulfide-bridged, but mainly non-covalent dimers in the cytosol. Heterodimers with BAX are formed exclusively in the MOM. Furthermore, our results suggest that BNIP3 interacts with the MOM directly via mitochondrial BAX. However, the physical interactions with BAX and the MOM did not affect the membrane potential and cell viability. These findings suggest that another stimulus other than the mere existence of the BNIP3/BAX dimer in the MOM is required to promote BNIP3 cell-death activity; this could be a potential disturbance of the BNIP3 distribution homeostasis, namely in the direction of the mitochondria.

  8. A Multinuclear Copper(I) Cluster Forms the Dimerization Interface in Copper-Loaded Human Copper Chaperone for Superoxide Dismutase

    SciTech Connect

    Stasser, J.P.; Siluvai, G.S.; Barry, A.N.; Blackburn, N.J.

    2009-06-04

    Copper binding and X-ray aborption spectroscopy studies are reported on untagged human CCS (hCCS; CCS = copper chaperone for superoxide dismutase) isolated using an intein self-cleaving vector and on single and double Cys to Ala mutants of the hCCS MTCQSC and CSC motifs of domains 1 (D1) and 3 (D3), respectively. The results on the wild-type protein confirmed earlier findings on the CCS-MBP (maltose binding protein) constructs, namely, that Cu(I) coordinates to the CXC motif, forming a cluster at the interface of two D3 polypeptides. In contrast to the single Cys to Ser mutations of the CCS-MBP protein (Stasser, J. P., Eisses, J. F., Barry, A. N., Kaplan, J. H., and Blackburn, N. J. (2005) Biochemistry 44, 3143-3152), single Cys to Ala mutations in D3 were sufficient to eliminate cluster formation and significantly reduce CCS activity. Analysis of the intensity of the Cu-Cu cluster interaction in C244A, C246A, and C244/246A variants suggested that the nuclearity of the cluster was greater than 2 and was most consistent with a Cu4S6 adamantane-type species. The relationship among cluster formation, oligomerization, and metal loading was evaluated. The results support a model in which Cu(I) binding converts the apo dimer with a D2-D2 interface to a new dimer connected by cluster formation at two D3 CSC motifs. The predominance of dimer over tetramer in the cluster-containing species strongly suggests that the D2 dimer interface remains open and available for sequestering an SOD1 monomer. This work implicates the copper cluster in the reactive form and adds detail to the cluster nuclearity and how copper loading affects the oligomerization states and reactivity of CCS for its partner SOD1.

  9. An Autoinhibited Dimeric Form of BAX Regulates the BAX Activation Pathway.

    PubMed

    Garner, Thomas P; Reyna, Denis E; Priyadarshi, Amit; Chen, Hui-Chen; Li, Sheng; Wu, Yang; Ganesan, Yogesh Tengarai; Malashkevich, Vladimir N; Almo, Steve S; Cheng, Emily H; Gavathiotis, Evripidis

    2016-08-04

    Pro-apoptotic BAX is a cell fate regulator playing an important role in cellular homeostasis and pathological cell death. BAX is predominantly localized in the cytosol, where it has a quiescent monomer conformation. Following a pro-apoptotic trigger, cytosolic BAX is activated and translocates to the mitochondria to initiate mitochondrial dysfunction and apoptosis. Here, cellular, biochemical, and structural data unexpectedly demonstrate that cytosolic BAX also has an inactive dimer conformation that regulates its activation. The full-length crystal structure of the inactive BAX dimer revealed an asymmetric interaction consistent with inhibition of the N-terminal conformational change of one protomer and the displacement of the C-terminal helix α9 of the second protomer. This autoinhibited BAX dimer dissociates to BAX monomers before BAX can be activated. Our data support a model whereby the degree of apoptosis induction is regulated by the conformation of cytosolic BAX and identify an unprecedented mechanism of cytosolic BAX inhibition. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Inhibition of platelet aggregation ex vivo is repressed in apolipoprotein E deficient mice.

    PubMed

    Carrier, É; Houde, M; Grandbois, M; Bkaily, G; Warner, T D; D'Orléans-Juste, P

    2017-08-01

    In the present study, we assessed whether the endogenous platelet inhibitory mechanisms are altered in the early to moderate stages of the atherosclerotic process. Apolipoprotein E deficient mice (ApoE-/-), a mouse model of atherosclerosis, and their wild-type (WT) counterparts were used to assess agonist-stimulated synthesis of prostacyclin (PGI2), inhibition of platelet aggregation ex vivo, and intra-platelet cAMP levels. Basal U46619 and ADP -induced platelet aggregation in vitro were increased in ApoE-/- mice at 18-20 weeks in comparison with 8-10 weeks of age. Systemically administered endothelin-1 (ET-1) or bradykinin (BK) inhibited platelet aggregation in a similar fashion in 8- to 10-week-old ApoE-/- and WT mice, but not in the ApoE-/- mice at 18-20 weeks of age, although both peptides maintained their capacity to increase plasma levels of the PGI2. Intravenous infusion of PGI2 also failed to inhibit platelet aggregation ex vivo in 18- to 20-week-old ApoE-/- mice. Interestingly, both BK and PGI2 retained their ability to increase intraplatelet cAMP in WT and ApoE-/- mice. Our results suggest that a loss of activity of endogenous inhibitorymechanisms could contribute to the increased platelet reactivity in ApoE-/- mice, and that this phenomenon occurs early in the intermediate stage of the atherosclerotic process.

  11. Apolipoprotein E4, cholinergic integrity and the pharmacogenetics of Alzheimer's disease.

    PubMed Central

    Poirier, J

    1999-01-01

    Recent evidence indicates that apolipoprotein E (apoE) plays a central role in the brain's response to injury. The coordinated expression of apoE and its receptors (the so-called LDL [low density lipoprotein] receptor family) appears to regulate the transport and internalization of cholesterol and phospholipids during the early phase of the re-innervation process in the adult brain. During dendritic remodelling and synaptogenesis, neurons progressively repress the synthesis of cholesterol in favour of cholesterol internalization through the apoE/LDL receptor pathway. The discovery a few years ago, that the apolipoprotein epsilon 4 allele found in 15% of the normal population is strongly linked to both sporadic and familial late-onset Alzheimer's disease (AD), raises the possibility that a dysfunction of the lipid transport system associated with compensatory sprouting and synaptic remodelling could be central to the AD process. The role of apoE in the central nervous system is particularly important in relation to the cholinergic system, which relies to a certain extent on the integrity of phospholipid homeostasis in neurons. Recent evidence obtained by 4 independent research teams indicates that apo epsilon 4 allele directly affects cholinergic activity in the brain of AD subjects. It was also shown to modulate the drug efficacy profile of several cholinomimetic and noncholinomimetic drugs used for the treatment of AD patients. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:10212558

  12. Bexarotene protects against traumatic brain injury in mice partially through apolipoprotein E.

    PubMed

    Zhong, Jianjun; Cheng, Chongjie; Liu, Han; Huang, Zhijian; Wu, Yue; Teng, Zhipeng; He, Junchi; Zhang, Hongrong; Wu, Jinchuan; Cao, Fang; Jiang, Li; Sun, Xiaochuan

    2017-02-20

    Bexarotene has been proved to have neuroprotective effects in many animal models of neurological diseases. However, its neuroprotection in traumatic brain injury (TBI) is still unknown. This study aims to explore the neuroprotective effects of bexarotene on TBI and its possible mechanism. Controlled cortical impact (CCI) model was used to simulate TBI in C57BL/6 mice as well as APOE gene knockout (APOE-KO) mice. After CCI, mice were daily dosed with bexarotene or vehicle solution intraperitoneally. The motor function, learning and memory, inflammatory factors, microglia amount, apoptosis condition around injury site and main side-effects were all measured. The results showed that, after CCI, bexarotene treatment markedly improved the motor function and spatial memory in C57BL/6 compare to APOE-KO mice which showed no improvement. The inflammatory cytokines, microglia amount, cell apoptosis rate, and protein of cleaved caspase-3 around the injury site were markedly upregulated after TBI in both C57BL/6 and APOE-KO mice, and all these upregulation were significantly mitigated by bexarotene treatment in C57BL/6 mice, but not in APOE-KO mice. No side-effects were detected after consecutive administration. Taken together, bexarotene inhibits the inflammatory response as well as cell apoptosis and improves the neurological function of mice after TBI partially through apolipoprotein E. This may make it a promising candidate for the therapeutic treatment after TBI.

  13. Apolipoprotein E4 and Insulin Resistance Interact to Impair Cognition and Alter the Epigenome and Metabolome

    PubMed Central

    Johnson, Lance A.; Torres, Eileen Ruth S.; Impey, Soren; Stevens, Jan F.; Raber, Jacob

    2017-01-01

    Apolipoprotein E4 (E4) and type 2 diabetes are major risk factors for cognitive decline and late onset Alzheimer’s disease (AD). E4-associated phenotypes and insulin resistance (IR) share several features and appear to interact in driving cognitive dysfunction. However, shared mechanisms that could explain their overlapping pathophysiology have yet to be found. We hypothesized that, compared to E3 mice, E4 mice would be more susceptible to the harmful cognitive effects of high fat diet (HFD)-induced IR due to apoE isoform-specific differences in brain metabolism. While both E3 and E4 mice fed HFD displayed impairments in peripheral metabolism and cognition, deficits in hippocampal-dependent spatial learning and memory were exaggerated in E4 mice. Combining genome-wide measures of DNA hydroxymethylation with comprehensive untargeted metabolomics, we identified novel alterations in purine metabolism, glutamate metabolism, and the pentose phosphate pathway. Finally, in E4 mice, the metabolic and cognitive deficiencies caused by HFD were rescued by switching to a low fat diet for one month, suggesting a functional role was associated with reversal of the same metabolic pathways described above. These results suggest a susceptibility of E4 carriers to metabolic impairments brought on by IR, and may guide development of novel therapies for cognitive decline and dementia. PMID:28272510

  14. Olive oils modulate fatty acid content and signaling protein expression in apolipoprotein E knockout mice brain.

    PubMed

    Alemany, Regina; Navarro, María A; Vögler, Oliver; Perona, Javier S; Osada, Jesús; Ruiz-Gutiérrez, Valentina

    2010-01-01

    Atherosclerosis contributes to disruption of neuronal signaling pathways by producing lipid-dependent modifications of brain plasma membranes, neuroinflammation and oxidative stress. We investigated whether long-term (11 weeks) consumption of refined- (ROO) and pomace- (POO) olive oil modulated the fatty acid composition and the levels of membrane signaling proteins in the brain of apolipoprotein E (apoE) knockout (KO) mice, an animal model of atherosclerosis. Both of these oils are rich in bioactive molecules with anti-inflammatory and antioxidant effects. ROO and POO long-term consumption increased the proportion of monounsaturated fatty acids (MUFAs), particularly of oleic acid, while reducing the level of the saturated fatty acids (SFAs) palmitic and stearic acid. As a result, the MUFA:SFA ratio was higher in apoE KO mice brain fed with ROO and POO. Furthermore, both oils reduced the level of arachidonic and eicosapentaenoic acid, suggesting a decrease in the generation of pro- and anti-inflammatory eicosanoids. Finally, ROO and POO induced an increase in the density of membrane proteins implicated in both the Galphas/PKA and Galphaq/PLCbeta1/PKCalpha signaling pathways. The combined effects of long-term ROO and POO consumption on fatty acid composition and the level of signaling proteins involved in PKA and PKC activation, suggest positive effects on neuroinflammation and brain function in apoE KO mice brain, and convert these oils into promising functional foods in diseases involving apoE deficiency.

  15. Apolipoprotein E gene polymorphisms in relation to chronic periodontitis, periodontopathic bacteria, and lipid levels.

    PubMed

    Borilova Linhartova, Petra; Bartova, Jirina; Poskerova, Hana; Machal, Jan; Vokurka, Jan; Fassmann, Antonin; Izakovicova Holla, Lydie

    2015-03-01

    Inflammatory periodontal diseases may be associated with common systemic conditions and, as recently described, alterations in lipid levels in the blood. The aim of this study was to determine the possible effects of apolipoprotein E (ApoE) genotypes on the lipid levels in healthy people and patients with chronic periodontitis (CP) in relation to periodontopathic bacteria. This case-control study comprised 469 unrelated subjects. The genomic DNA of 294 patients with CP and 175 healthy/non-periodontitis controls were genotyped, using the real-time polymerase chain reaction (RT-PCR) method, for ApoE (rs429358 and rs7412) gene polymorphisms. Subgingival bacterial colonization was investigated by the DNA microarray using a periodontal pathogen detection kit and lipid levels were measured in a subgroup of subjects (N = 275). There was no evidence for a significant association between ApoE gene polymorphisms and CP (P > 0.05). Patients with CP had increased levels of total cholesterol and low-density lipoprotein (LDL) compared to controls (P< 0.05); however, no significant difference was found for triglyceride and high-density lipoprotein (HDL) levels. ApoE gene variability influenced LDL levels marginally (P = 0.08) but it did not modify total cholesterol, triglyceride, and HDL levels or the occurrence of periodontal pathogens in subgingival pockets.(23) CONCLUSIONS: In the Czech population studied, ApoE genetic variations were not associated with susceptibility to CP or the presence of periodontopathic bacteria. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Low Density Lipoprotein Receptor-Related Protein and Apolipoprotein E Expression is Altered in Schizophrenia

    PubMed Central

    Gibbons, Andrew Stuart; Thomas, Elizabeth A.; Scarr, Elizabeth; Dean, Brian

    2010-01-01

    Our recent microarray study reported altered mRNA expression of several low density lipoprotein receptor-related proteins (LRP) associated with the first 4 years following diagnosis with schizophrenia. Whilst this finding is novel, apolipoprotein E (APOE), which mediates its activity through LRPs, has been reported by several studies to be altered in brains of subjects with schizophrenia. We used qPCR to measure the expression of LRP2, LRP4, LRP6, LRP8, LRP10 and LRP12 mRNA in Brodmann's area (BA) 46 of the dorsolateral prefrontal cortex in 15 subjects with short duration of illness schizophrenia (SDS) and 15 pair matched controls. We also used Western blotting to measure APOE protein expression in BA46 from these subjects. Amongst the LRPs examined, LRP10 expression was significantly increased (P = 0.03) and LRP12 was significantly decreased (P < 0.01) in SDS. APOE protein expression was also increased in SDS (P = 0.01). No other marker examined in this study was altered with diagnosis. Our data supports a role for distinct members of the LRP family in the pathology of schizophrenia and adds weight to the hypothesis that aberrant apolipoprotein signaling is involved in the early stages of schizophrenia. PMID:21423430

  17. An apolipoprotein E-mimetic stimulates axonal regeneration and remyelination after peripheral nerve injury.

    PubMed

    Li, Feng-Qiao; Fowler, Kenneth A; Neil, Jessica E; Colton, Carol A; Vitek, Michael P

    2010-07-01

    Elevated apolipoprotein E (apoE) synthesis within crushed sciatic nerves advocates that apoE could benefit axonal repair and reconstruction of axonal and myelin membranes. We created an apoE-mimetic peptide, COG112 (acetyl-RQIKIWFQNRRMKWKKCLRVRLASHLRKLRKRLL-amide), and found that postinjury treatment with COG112 significantly improved recovery of motor and sensory function following sciatic nerve crush in C57BL/6 mice. Morphometric analysis of injured sciatic nerves revealed that COG112 promoted axonal regrowth after 2 weeks of treatment. More strikingly, the thickness of myelin sheaths was increased by COG112 treatment. Consistent with these histological findings, COG112 potently elevated growth associated protein 43 (GAP-43) and peripheral myelin protein zero (P0), which are markers of axon regeneration and remyelination, respectively. Electron microscopic examination further suggested that the apoE-mimetic COG112 may increase clearance of myelin debris. Schwann cell uptake of cholesterol-containing low-density lipoprotein particles was selectively enhanced by COG112 treatment in a Schwann cell line S16. Moreover, COG112 significantly promoted axon elongation in primary dorsal root ganglion cultures from rat pups. Considering that cholesterol and lipids are needed for reconstructing myelin sheaths and axon extension, these data support a hypothesis where supplementation with exogenous apoE-mimetics such as COG112 may be a promising strategy for restoring lost functional and structural elements following nerve injury.

  18. Apolipoprotein E and lipid homeostasis in the etiology and treatment of sporadic Alzheimer's disease.

    PubMed

    Poirier, Judes; Miron, Justin; Picard, Cynthia; Gormley, Patrick; Théroux, Louise; Breitner, John; Dea, Doris

    2014-09-01

    The discovery that the apolipoprotein E (apoE) ε4 allele is genetically linked to both sporadic and familial late-onset Alzheimer's disease (AD) raises the possibility that a dysfunction of the lipid transport system could seriously affect lipid homeostasis in the brain of AD subjects. The presence of the ε4 allele has been associated with lower levels of apoE in both serum and brain tissues of normal and AD subjects. In an attempt to reverse the apoE deficit in AD, we identified and characterized several apoE inducer agents using a low-throughput in vitro screening assay. The most promising of these compounds is called probucol. Administration of probucol, an old cholesterol-lowering drug, in a pilot trial in mild-to-moderate sporadic AD led to a significant increase in cerebrospinal fluid (CSF) apoE levels and a decrease in CSF in both phosphorylated tau 181 and beta-amyloid 1-42 concentrations without significant modifications of lipid hydroperoxide levels.

  19. Apolipoprotein E ε4 does not affect cognitive performance in patients with Parkinson's disease.

    PubMed

    Mengel, David; Dams, Judith; Ziemek, Jannis; Becker, Julian; Balzer-Geldsetzer, Monika; Hilker, Rüdiger; Baudrexel, Simon; Kalbe, Elke; Schmidt, Nele; Witt, Karsten; Liepelt-Scarfone, Inga; Gräber, Susanne; Petrelli, Annette; Neuser, Petra; Schulte, Claudia; Linse, Katharina; Storch, Alexander; Wittchen, Hans-Ulrich; Riedel, Oliver; Mollenhauer, Brit; Ebentheuer, Jens; Trenkwalder, Claudia; Klockgether, Thomas; Spottke, Annika; Wüllner, Ullrich; Schulz, Jörg B; Reetz, Kathrin; Heber, Ines Ann; Ramirez, Alfredo; Dodel, Richard

    2016-08-01

    Cognitive impairment is a common and disabling non-motor symptom in Parkinson's disease (PD). The apolipoprotein E (APOE) allele ε4 is a known risk factor for Alzheimer's disease and has also been suggested to be a risk factor for dementia in PD and even a predictor of impairment in certain cognitive domains. A total of 447 PD patients (PD patients without cognitive impairment: n = 187; PD patients with mild cognitive impairment: n = 188; PD patients with dementia: n = 72) were included from an ongoing observational German multicenter cohort study (LANDSCAPE study). All patients underwent an extensive neuropsychological test battery, including assessments of memory, visuospatial functioning, attention, language, and executive function. APOE genotype was determined by an allelic discrimination assay. Linear regression analysis was used to explore the associations between APOE-ε4 and cognitive performance. The APOE-ε4 allele was not associated with a diagnosis of cognitive impairment in PD (PD with mild cognitive impairment and PD with dementia) or with deficits in specific neuropsychological domains in our study cohort. Our data question the relevance of the APOE-ε4 allele as a predictor of cognitive impairment in PD. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Does apolipoprotein E influence learning and memory in the nondemented oldest old?

    PubMed

    Salo, A; Ylikoski, R; Verkkoniemi, A; Polvikoski, T; Juva, K; Rastas, S; Kontula, K; Kainulainen, K; Niinistö, L; Notkola, I L; Sulkava, R

    2001-12-01

    The objective of this study was to analyze the relationship of the apolipoprotein E (apoE) epsilon4 and epsilon2 alleles to learning and memory performances in the nondemented oldest old. Forty-six nondemented persons aged 85 years or over from a randomly selected group of 128 subjects in Vantaa, Finland, were studied. ApoE genotyping was performed using the minisequencing technique. A structured clinical examination and interview were carried out. The test variables studied were learning and memory scores (from the Fuld Object-Memory Evaluation), verbal fluency, and conceptualization (the Similarities subtest of the WAIS-R). We compared apoE-epsilon4 carriers to noncarriers and apoE-epsilon2 carriers to noncarriers. No statistically significant differences were found in any of the test variables. The results failed to confirm the hypotheses that poor cognitive performance is associated with the apoE-epsilon4 allele and good performance with the apoE-epsilon2 allele in the oldest old. This suggests that the apoE alleles do not have a detectable relationship to learning and memory in nondemented very elderly people.

  1. Apolipoprotein E polymorphisms increase the risk of post-stroke depression

    PubMed Central

    Li, Xue-bin; Wang, Jie; Xu, An-ding; Huang, Jian-min; Meng, Lan-qing; Huang, Rui-ya; Wang, Jun-li

    2016-01-01

    Recent reports have shown that apolipoprotein E (APOE) polymorphisms are involved in neurodegenerative disease. However, it is unclear whether APOE affects post-stroke depression. Accordingly, we hypothesized that APOE polymorphisms modify the risk of post-stroke depression. Here, we performed a hospital-based case-control study (including 76 cerebral infarction cases with post-stroke depression, 88 cerebral infarction cases without post-stroke depression, and 109 controls without any evidence of post-stroke depression or cerebral infarction) to determine possible association between APOE rs429358 and rs7412 polymorphisms and risk of post-stroke depression. Our findings show no difference among the groups with regards genotype distribution of the rs7412 polymorphism. In contrast, APOE genotypes with rs429358-C alleles increased the risk of post-stroke depression. Further, the rs429358 polymorphism was associated with significantly decreased regional cerebral blood flow values in the left temporal lobe of post-stroke depression cases. Additionally, the rs429358 polymorphism was not only associated with depression severity, but with increasing serum levels of total cholesterol. These results suggest that the APOE rs429358 polymorphism is associated with increased risk of developing post-stroke depression, and that APOE rs429358-C allele genotypes may be detrimental to recovery of nerve function after stoke. Indeed, these findings provide clinical data for future post-stroke depression gene interventions. PMID:28123423

  2. Apolipoprotein E mediation of neuro-inflammation in a murine model of multiple sclerosis.

    PubMed

    Shin, Soomin; Walz, Katharine A; Archambault, Angela S; Sim, Julia; Bollman, Bryan P; Koenigsknecht-Talboo, Jessica; Cross, Anne H; Holtzman, David M; Wu, Gregory F

    2014-06-15

    Apolipoprotein E (ApoE) functions as a ligand in receptor-mediated endocytosis of lipoprotein particles and has been demonstrated to play a role in antigen presentation. To explore the contribution of ApoE during autoimmune central nervous system (CNS) demyelination, we examined the clinical, cellular immune function, and pathologic consequences of experimental autoimmune encephalomyelitis (EAE) induction in ApoE knockout (ApoE(-/-)) mice. We observed reduced clinical severity of EAE in ApoE(-/-) mice in comparison to WT mice that was concomitant with an early reduction of dendritic cells (DCs) followed by a reduction of additional innate cells in the spinal cord at the peak of disease without any differences in axonal damage. While T cell priming was enhanced in ApoE(-/-) mice, reduced severity of EAE was also observed in ApoE(-/-) recipients of encephalitogenic wild type T cells. Expression of ApoE during EAE was elevated within the CNS of wild type mice, particularly by innate cells such as DCs. Overall, ApoE promotes clinical EAE, likely by mediation of inflammation localized within the CNS. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Topology of human apolipoprotein E3 uniquely regulates its diverse biological functions

    PubMed Central

    Chen, Jianglei; Li, Qianqian; Wang, Jianjun

    2011-01-01

    Human apolipoprotein E (apoE) is one of the major determinants in lipid transport, playing a critical role in atherosclerosis and other diseases. Binding to lipid and heparan sulfate proteoglycans (HSPG) induces apoE to adopt active conformations for binding to low-density lipoprotein receptor (LDLR) family. ApoE also interacts with beta amyloid peptide, manifests critical isoform-specific effects on Alzheimer’s disease. Despite the importance of apoE in these major human diseases, the fundamental questions of how apoE adjusts its structure upon binding to regulate its diverse functions remain unsolved. We report the NMR structure of apoE3, displaying a unique topology of three structural domains. The C-terminal domain presents a large exposed hydrophobic surface that likely initiates interactions with lipids, HSPG, and beta amyloid peptides. The unique topology precisely regulates apoE tertiary structure to permit only one possible conformational adaptation upon binding and provides a double security in preventing lipid-free and partially-lipidated apoE from premature binding to apoE receptors during receptor biogenesis. This topology further ensures the optimal receptor-binding activity by the fully lipidated apoE during lipoprotein transport in circulation and in the brain. These findings provide a structural framework for understanding the structural basis of the diverse functions of this important protein in human diseases. PMID:21873229

  4. Association between Apolipoprotein E Variants and Obesity-Related Traits in Mexican School Children.

    PubMed

    Rodríguez-Carmona, Yanelli; Pérez-Rodríguez, Marcela; Gámez-Valdez, Eli; López-Alavez, Francisco J; Hernández-Armenta, Claudia I; Vega-Monter, Norma; Leyva-García, Gerardo; Monge-Cázares, Tulia; Barrera Valencia, Daniela; Balderas Monroy, Marisol; Pfeffer, Frania; Meléndez, Guillermo; Pérez Lizaur, Ana Bertha; Pardío, Jeanette; Tejero, María Elizabeth

    2014-01-01

    Genetic variation in apolipoprotein E (ApoE) has a key role in lipid metabolism. However, its contribution to the amount and distribution of body fat is under investigation. The aim of this study was to analyze the association between genetic variation in ApoE and obesity-related traits in Mexican school children. Anthropometric, body composition and physical activity measures were conducted using standard methods in 300 children (177 girls/123 boys) who fulfilled the inclusion criteria. DNA was isolated from saliva. ApoE genotypes were analyzed by allelic discrimination. The association between variation in ApoE and anthropometric and body composition measures was investigated using the General Linear Model. The mean±SD values for age, body mass index (BMI) and waist circumference (WC) were 9.05±0.80 years, 19.01±3.83 and 67.98±10.97 cm, respectively. Approximately 46% of the participants were overweight or obese. A significant association between ApoE isoforms and WC was found after controlling for age, sex and the percentage of physical activity (p=0.025). Significant main effects were found for vigorous physical activity and light physical activity influencing the adiposity-related BMI (p<0.001) and WC (p=0.044), respectively. Variation in ApoE and physical activity intensity were associated with adiposity-related phenotypes in Mexican school children. © 2015 S. Karger AG, Basel.

  5. Differential regulation of amyloid-β endocytic trafficking and lysosomal degradation by apolipoprotein E isoforms.

    PubMed

    Li, Jie; Kanekiyo, Takahisa; Shinohara, Mitsuru; Zhang, Yunwu; LaDu, Mary Jo; Xu, Huaxi; Bu, Guojun

    2012-12-28

    Aggregation of amyloid-β (Aβ) peptides leads to synaptic disruption and neurodegeneration in Alzheimer disease (AD). A major Aβ clearance pathway in the brain is cellular uptake and degradation. However, how Aβ traffics through the endocytic pathway and how AD risk factors regulate this event is unclear. Here we show that the majority of endocytosed Aβ in neurons traffics through early and late endosomes to the lysosomes for degradation. Overexpression of Rab5 or Rab7, small GTPases that function in vesicle fusion for early and late endosomes, respectively, significantly accelerates Aβ endocytic trafficking to the lysosomes. We also found that a portion of endocytosed Aβ traffics through Rab11-positive recycling vesicles. A blockage of this Aβ recycling pathway with a constitutively active Rab11 mutant significantly accelerates cellular Aβ accumulation. Inhibition of lysosomal enzymes results in Aβ accumulation and aggregation. Importantly, apolipoprotein E (apoE) accelerates neuronal Aβ uptake, lysosomal trafficking, and degradation in an isoform-dependent manner with apoE3 more efficiently facilitating Aβ trafficking and degradation than apoE4, a risk factor for AD. Taken together, our results demonstrate that Aβ endocytic trafficking to lysosomes for degradation is a major Aβ clearance pathway that is differentially regulated by apoE isoforms. A disturbance of this pathway can lead to accumulation and aggregation of cellular Aβ capable of causing neurotoxicity and seeding amyloid.

  6. Apolipoprotein E-Mimetic COG1410 Reduces Acute Vasogenic Edema following Traumatic Brain Injury.

    PubMed

    Cao, Fang; Jiang, Yong; Wu, Yue; Zhong, Jianjun; Liu, Jieshi; Qin, Xinghu; Chen, Ligang; Vitek, Michael P; Li, Fengqiao; Xu, Lu; Sun, Xiaochuan

    2016-01-15

    The degree of post-traumatic brain edema and dysfunction of the blood-brain barrier (BBB) influences the neurofunctional outcome after a traumatic brain injury (TBI). Previous studies have demonstrated that the administration of apolipoprotein E-mimetic peptide COG1410 reduces the brain water content after subarachnoid hemorrhage, intra-cerebral hemorrhage, and focal brain ischemia. However, the effects of COG1410 on vasogenic edema following TBI are not known. The current study evaluated the effects of 1 mg/kg daily COG1410 versus saline administered intravenously after a controlled cortical impact (CCI) injury on BBB dysfunction and vasogenic edema at an acute stage in mice. The results demonstrated that treatment with COG1410 suppressed the activity of matrix metalloproteinase-9, reduced the disruption of the BBB and Evans Blue dye extravasation, reduced the TBI lesion volume and vasogenic edema, and decreased the functional deficits compared with mice treated with vehicle, at an acute stage after CCI. These findings suggest that COG1410 is a promising preclinical therapeutic agent for the treatment of traumatic brain injury.

  7. Osteopontin deficiency reduces kidney damage from hypercholesterolemia in Apolipoprotein E-deficient mice

    PubMed Central

    Pei, Zouwei; Okura, Takafumi; Nagao, Tomoaki; Enomoto, Daijiro; Kukida, Masayoshi; Tanino, Akiko; Miyoshi, Ken-ichi; Kurata, Mie; Higaki, Jitsuo

    2016-01-01

    Hypercholesterolemia is a well-established risk factor for kidney injury, which can lead to chronic kidney disease (CKD). Osteopontin (OPN) has been implicated in the pathology of several renal conditions. This study was to evaluate the effects of OPN on hypercholesterolemia induced renal dysfunction. Eight-week-old male mice were divided into 4 groups: apolipoprotein E knockout (ApoE−/−) and ApoE/OPN knockout (ApoE−/−/OPN−/−) mice fed a normal diet (ND) or high cholesterol diet (HD). After 4 weeks, Periodic acid-Schiff (PAS) and oil red O staining revealed excessive lipid deposition in the glomeruli of ApoE−/−HD mice, however, significantly suppressed in ApoE−/−/OPN−/−HD mice. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) expression was lower in the glomeruli of ApoE−/−/OPN−/−HD mice than ApoE−/−HD mice. In vitro study, primary mesangial cells were incubated with recombinant mouse OPN (rmOPN). RmOPN induced LOX-1 mRNA and protein expression in primary mesangial cells. Pre-treatment with an ERK inhibitor suppressed the LOX-1 gene expression induced by rmOPN. These results indicate that OPN contributes to kidney damage in hypercholesterolemia and suggest that inhibition of OPN may provide a potential therapeutic target for the prevention of hypercholesterolemia. PMID:27353458

  8. Apolipoprotein E and alpha brain rhythms in mild cognitive impairment: a multicentric electroencephalogram study.

    PubMed

    Babiloni, Claudio; Benussi, Luisa; Binetti, Giuliano; Cassetta, Emanuele; Dal Forno, Gloria; Del Percio, Claudio; Ferreri, Florinda; Ferri, Raffaele; Frisoni, Giovanni; Ghidoni, Roberta; Miniussi, Carlo; Rodriguez, Guido; Romani, Gian Luca; Squitti, Rosanna; Ventriglia, Maria Carla; Rossini, Paolo M

    2006-02-01

    Relationships between the apolipoprotein E epsilon4 allele and electroencephalographic (EEG) rhythmicity have been demonstrated in Alzheimer's disease (AD) patients but not in the preclinical stage prodromic to it, namely, mild cognitive impairment (MCI). The present multicentric EEG study tested the hypothesis that presence of epsilon4 affects sources of resting EEG rhythms in both MCI and AD subjects. We enrolled 89 MCI subjects (34.8% with epsilon4) and 103 AD patients (50.4% with epsilon4). Resting eyes-closed EEG data were recorded for all subjects. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by low-resolution brain electromagnetic tomography. Results showed that amplitude of alpha 1 and 2 sources in occipital, temporal, and limbic areas was lower in subjects carrying the epsilon4 allele than in those not carrying the epsilon4 allele (p < 0.01). This was true for both MCI and AD. For the first time to our knowledge, a relationship was shown between ApoE genotype and global neurophysiological phenotype (ie, cortical alpha rhythmicity) in a preclinical AD condition, MCI, in addition to clinically manifest AD. Such a demonstration motivates future genotype-EEG phenotype studies for the early prediction of AD conversion in individual MCI subjects.

  9. C-terminal interactions of apolipoprotein E4 respond to the postprandial state.

    PubMed

    Tetali, Sarada D; Budamagunta, Madhu S; Voss, John C; Rutledge, John C

    2006-07-01

    Increased triglyceride-rich lipoproteins (TGRLs) in the postprandial state are associated with atherosclerosis. We investigated whether the postprandial state induced structural changes at the apolipoprotein E4 (apoE4) C terminus, its principal lipid binding domain, using electron paramagnetic resonance (EPR) spectroscopy of a site-directed spin label attached to the cysteine of apoE4-W264C. Spin coupling between labels located in the C termini was followed after mixing with preprandial and postprandial human plasma samples. Our results indicate that postprandial plasma triggers a reorganization of the protein such that the dipolar broadening is diminished, indicating a reduction in C-terminal interaction. The loss of spectral broadening was directly correlated with an increase in postprandial plasma triglycerides and was reduced with delipidated plasma. The spin-labeled apoE4 displayed a lipid preference of VLDL > LDL > HDL in the preprandial and postprandial states. The apoE4 shift to VLDL during the postprandial state was accompanied by a loss in spectral broadening of the protein. These findings suggest that apoE4 associated with LDL maintains self-association via its C terminus and that this association is diminished in VLDL-associated protein. Lipolyzed TGRL reflected a depletion of the C-terminal interaction of apoE4. Addition of palmitate to VLDL gave a similar response as lipolyzed TGRL, suggesting that lipolysis products play a major role in reorganizing apoE4 during the postprandial state.

  10. Evolutionary analysis of apolipoprotein E by Maximum Likelihood and complex network methods

    PubMed Central

    Benevides, Leandro de Jesus; de Carvalho, Daniel Santana; Andrade, Roberto Fernandes Silva; Bomfim, Gilberto Cafezeiro; Fernandes, Flora Maria de Campos

    2016-01-01

    Abstract Apolipoprotein E (apo E) is a human glycoprotein with 299 amino acids, and it is a major component of very low density lipoproteins (VLDL) and a group of high-density lipoproteins (HDL). Phylogenetic studies are important to clarify how various apo E proteins are related in groups of organisms and whether they evolved from a common ancestor. Here, we aimed at performing a phylogenetic study on apo E carrying organisms. We employed a classical and robust method, such as Maximum Likelihood (ML), and compared the results using a more recent approach based on complex networks. Thirty-two apo E amino acid sequences were downloaded from NCBI. A clear separation could be observed among three major groups: mammals, fish and amphibians. The results obtained from ML method, as well as from the constructed networks showed two different groups: one with mammals only (C1) and another with fish (C2), and a single node with the single sequence available for an amphibian. The accordance in results from the different methods shows that the complex networks approach is effective in phylogenetic studies. Furthermore, our results revealed the conservation of apo E among animal groups. PMID:27560837

  11. A possible role of apolipoprotein E polymorphism in predisposition to higher education.

    PubMed

    Hubacek, J A; Pitha, J; Skodová, Z; Adámková, V; Lánská, V; Poledne, R

    2001-01-01

    A potential candidate gene that could contribute to the education process is the apolipoprotein E (apo E) gene that has been shown to correlate with memory function and memory decline. We measured apo E polymorphism in groups of probands with different levels of education selected from a population sample. In the group of probands with higher education (n = 82), 24.4% had the e4 allele, compared with 7.3% who had the e2 allele. A reverse association was found in the group that left school aged 15 (n = 36) - 8.3% had the e4 allele and 13.9% had the e2 allele. Eighty-seven percent of the probands with the allele e4 reached higher education, compared to only 54.5% with the allele e2. The difference between the groups is statistically significant (p = 0.039), and this may indicate some role for the apo E polymorphism in subjects' intelligence or ability to learn.

  12. 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.

  13. Apolipoprotein E in Synaptic Plasticity and Alzheimer’s Disease: Potential Cellular and Molecular Mechanisms

    PubMed Central

    Kim, Jaekwang; Yoon, Hyejin; Basak, Jacob; Kim, Jungsu

    2014-01-01

    Alzheimer’s disease (AD) is clinically characterized with progressive memory loss and cognitive decline. Synaptic dysfunction is an early pathological feature that occurs prior to neurodegeneration and memory dysfunction. Mounting evidence suggests that aggregation of amyloid-β (Aβ) and hyperphosphorylated tau leads to synaptic deficits and neurodegeneration, thereby to memory loss. Among the established genetic risk factors for AD, the ɛ4 allele of apolipoprotein E (APOE) is the strongest genetic risk factor. We and others previously demonstrated that apoE regulates Aβ aggregation and clearance in an isoform-dependent manner. While the effect of apoE on Aβ may explain how apoE isoforms differentially affect AD pathogenesis, there are also other underexplored pathogenic mechanisms. They include differential effects of apoE on cerebral energy metabolism, neuroinflammation, neurovascular function, neurogenesis, and synaptic plasticity. ApoE is a major carrier of cholesterols that are required for neuronal activity and injury repair in the brain. Although there are a few conflicting findings and the underlying mechanism is still unclear, several lines of studies demonstrated that apoE4 leads to synaptic deficits and impairment in long-term potentiation, memory and cognition. In this review, we summarize current understanding of apoE function in the brain, with a particular emphasis on its role in synaptic plasticity and the underlying cellular and molecular mechanisms, involving low-density lipoprotein receptor-related protein 1 (LRP1), syndecan, and LRP8/ApoER2. PMID:25358504

  14. Disruption of p21-activated kinase 1 gene diminishes atherosclerosis in apolipoprotein E-deficient mice

    PubMed Central

    Singh, Nikhlesh K.; Kotla, Sivareddy; Dyukova, Elena; Traylor Jr., James G.; Orr, A. Wayne; Chernoff, Jonathan; Marion, Tony N.; Rao, Gadiparthi N.

    2015-01-01

    Pak1 plays an important role in various cellular processes, including cell motility, polarity, survival and proliferation. To date, its role in atherogenesis has not been explored. Here we report the effect of Pak1 on atherogenesis using atherosclerosis-prone apolipoprotein E-deficient (ApoE−/−) mice as a model. Disruption of Pak1 in ApoE−/− mice results in reduced plaque burden, significantly attenuates circulating IL-6 and MCP-1 levels, limits the expression of adhesion molecules and diminishes the macrophage content in the aortic root of ApoE−/− mice. We also observed reduced oxidized LDL uptake and increased cholesterol efflux by macrophages and smooth muscle cells of ApoE−/−:Pak1−/− mice as compared with ApoE−/− mice. In addition, we detect increased Pak1 phosphorylation in human atherosclerotic arteries, suggesting its role in human atherogenesis. Altogether, these results identify Pak1 as an important factor in the initiation and progression of atherogenesis. PMID:26104863

  15. Extracellular Proteolysis of Apolipoprotein E (apoE) by Secreted Serine Neuronal Protease

    PubMed Central

    Tamboli, Irfan Y.; Heo, Dongeun; Rebeck, G. William

    2014-01-01

    Under normal conditions, brain apolipoprotein E (apoE) is secreted and lipidated by astrocytes, then taken up by neurons via receptor mediated endocytosis. Free apoE is either degraded in intraneuronal lysosomal compartments or released. Here we identified a novel way by which apoE undergoes proteolysis in the extracellular space via a secreted neuronal protease. We show that apoE is cleaved in neuronal conditioned media by a secreted serine protease. This apoE cleavage was inhibited by PMSF and α1-antichymotrypsin, but not neuroserpin-1 or inhibitors of thrombin and cathepsin G, supporting its identity as a chymotrypsin like protease. In addition, apoE incubation with purified chymotrypsin produced a similar pattern of apoE fragments. Analysis of apoE fragments by mass spectrometry showed cleavages occuring at the C-terminal side of apoE tryptophan residues, further supporting our identification of cleavage by chymotrypsin like protease. Hippocampal neurons were more efficient in mediating this apoE cleavage than cortical neurons. Proteolysis of apoE4 generated higher levels of low molecular weight fragments compared to apoE3. Primary glial cultures released an inhibitor of this proteolytic activity. Together, these studies reveal novel mechanism by which apoE can be regulated and therefore could be useful in designing apoE directed AD therapeutic approaches. PMID:24675880

  16. Apolipoprotein E genotype and cognitive function in postmenopausal women with early-stage breast cancer.

    PubMed

    Koleck, Theresa A; Bender, Catherine M; Sereika, Susan M; Ahrendt, Gretchen; Jankowitz, Rachel C; McGuire, Kandace P; Ryan, Christopher M; Conley, Yvette P

    2014-11-01

    To examine the role of apolipoprotein E (APOE) genotype in the cognitive function of postmenopausal women with early-stage breast cancer prior to initiation of adjuvant therapy and over time with treatment. Longitudinal, genetic association study. Urban university cancer center. Three cohorts of postmenopausal women: 37 women with breast cancer receiving chemotherapy and anastrozole, 41 women with breast cancer receiving anastrozole alone, and 50 healthy women. Cognitive function was evaluated three times during a 12-month period using a comprehensive neuropsychological test battery. Participants were genotyped and classified based on the presence or absence of at least one APOE e4 allele. Multiple linear regression was used to determine if APOE genotype accounted for observed variability in cognitive function data. APOE genotype, breast cancer treatment, and cognitive function. Performance or changes in performance on tasks of executive function, attention, verbal learning and memory, and visual learning and memory were found to be influenced by APOE genotype and/or interactions between APOE genotype and study cohort. The results indicate that cognitive function in postmenopausal women with breast cancer is modified by APOE genotype and the combination of APOE genotype and treatment. APOE genotype, along with other biomarkers, may be used in the future to assist nurses in identifying women with breast cancer most at risk for cognitive decline.

  17. Extracellular proteolysis of apolipoprotein E (apoE) by secreted serine neuronal protease.

    PubMed

    Tamboli, Irfan Y; Heo, Dongeun; Rebeck, G William

    2014-01-01

    Under normal conditions, brain apolipoprotein E (apoE) is secreted and lipidated by astrocytes, then taken up by neurons via receptor mediated endocytosis. Free apoE is either degraded in intraneuronal lysosomal compartments or released. Here we identified a novel way by which apoE undergoes proteolysis in the extracellular space via a secreted neuronal protease. We show that apoE is cleaved in neuronal conditioned media by a secreted serine protease. This apoE cleavage was inhibited by PMSF and α1-antichymotrypsin, but not neuroserpin-1 or inhibitors of thrombin and cathepsin G, supporting its identity as a chymotrypsin like protease. In addition, apoE incubation with purified chymotrypsin produced a similar pattern of apoE fragments. Analysis of apoE fragments by mass spectrometry showed cleavages occurring at the C-terminal side of apoE tryptophan residues, further supporting our identification of cleavage by chymotrypsin like protease. Hippocampal neurons were more efficient in mediating this apoE cleavage than cortical neurons. Proteolysis of apoE4 generated higher levels of low molecular weight fragments compared to apoE3. Primary glial cultures released an inhibitor of this proteolytic activity. Together, these studies reveal novel mechanism by which apoE can be regulated and therefore could be useful in designing apoE directed AD therapeutic approaches.

  18. Apolipoprotein E polymorphism in alagille syndrome and progressive familial intrahepatic cholestasis.

    PubMed

    Socha, P; Nowicka, G; Jankowska, I; Rujner, J; Pawłowska, J; Socha, J

    2000-04-01

    The aim of the study was to assess the apolipoprotein E polymorphism (apoE) in two familial cholestatic diseases-Alagille syndrome (AS) and progressive familial intrahepatic cholestasis (PFIC)-and to estimate its association with gallstone formation, cholesterol levels, and response to UDCA treatment. We investigated 16 children with AS age 8.8 +/- 5.7 years (mean +/- SD) and 18 children with PFIC age 6.3 +/- 4.6 years. The frequency of the epsilon-2 allele in AS and PFIC was higher and the frequency of the epsilon-3 allele was lower than in controls. Gallstones were diagnosed in nine children with PFIC and different apoE phenotypes. No association between phenotype and cholesterol levels or response to UDCA therapy was observed in the patients studied. In conclusion, the allele epsilon-2 is overrepresented in AS and PFIC, similar to primary biliary cirrhosis, although this does not seem to contribute to different cholesterol levels, gallstones, and response to UDCA therapy.

  19. Color multiplexing hybridization probes using the apolipoprotein E locus as a model system for genotyping.

    PubMed

    Bernard, P S; Pritham, G H; Wittwer, C T

    1999-09-10

    Fluorescent hybridization probes were multiplexed for color genotyping of the apolipoprotein E locus using model oligonucleotide targets. Fluorescence resonance energy transfer was observed during adjacent hybridization of 3'-fluorescein-labeled "donor" probes paired with 5'-labeled "acceptor" probes with different emission spectra reporting at codons 112 and 158. The acceptor dyes emitted at either 640 nm (LightCycler Red 640) or 705 nm (LightCycler Red 705) and were monitored with a LightCycler, a thermal cycler with an integrated fluorimeter. The color of the acceptor dye identified each site and the characteristic melting temperatures of the fluorescein-labeled probes identified single base changes within each codon. Color compensation of temperature-dependent spectral overlap was applied to completely separate each channel. Competition between the probes and the complementary strand for the target sequence decreased resonance energy transfer, indicating an advantage of single-stranded target. Hybridization probes of the same length, but different GC content are T(m) shifted by the same amount during A:C mismatch duplex melting. Genotyping was optimal at both sites if melting curve analysis was preceded by a slow (1 degrees C/s) annealing phase. Although each site preferred different concentrations of Mg(2+) and target strand for optimal genotyping, conditions for multiplexing were found. This method, along with an appropriate amplification technique, should allow real-time multiplex genotyping from genomic DNA.

  20. Consumption of hydrogen water prevents atherosclerosis in apolipoprotein E knockout mice.

    PubMed

    Ohsawa, Ikuroh; Nishimaki, Kiyomi; Yamagata, Kumi; Ishikawa, Masahiro; Ohta, Shigeo

    2008-12-26

    Oxidative stress is implicated in atherogenesis; however most clinical trials with dietary antioxidants failed to show marked success in preventing atherosclerotic diseases. We have found that hydrogen (dihydrogen; H(2)) acts as an effective antioxidant to reduce oxidative stress [I. Ohsawa, M. Ishikawa, K. Takahashi, M. Watanabe, K. Nishimaki, K. Yamagata, K. Katsura, Y. Katayama, S, Asoh, S. Ohta, Hydrogen acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals, Nat. Med. 13 (2007) 688-694]. Here, we investigated whether drinking H(2)-dissolved water at a saturated level (H(2)-water) ad libitum prevents arteriosclerosis using an apolipoprotein E knockout mouse (apoE(-/-)), a model of the spontaneous development of atherosclerosis. ApoE(-/-) mice drank H(2)-water ad libitum from 2 to 6 month old throughout the whole period. Atherosclerotic lesions were significantly reduced by ad libitum drinking of H(2)-water (p=0.0069) as judged by Oil-Red-O staining series of sections of aorta. The oxidative stress level of aorta was decreased. Accumulation of macrophages in atherosclerotic lesions was confirmed. Thus, consumption of H(2)-dissolved water has the potential to prevent arteriosclerosis.

  1. Intracellular trafficking of recycling apolipoprotein E in Chinese hamster ovary cells.

    PubMed

    Braun, Nicole A; Mohler, Peter J; Weisgraber, Karl H; Hasty, Alyssa H; Linton, MacRae F; Yancey, Patricia G; Su, Yan Ru; Fazio, Sergio; Swift, Larry L

    2006-06-01

    We have investigated apolipoprotein E (apoE) recycling in Chinese hamster ovary (CHO) cells, a peripheral cell that does not produce lipoproteins or express apoE. Using a pulse-chase protocol in which cells were pulsed with 125I-apoE-VLDL and chased for different periods, approximately 30% of the apoE internalized during the pulse was resecreted within a 4 h chase in a relatively lipid-free state. The addition of lysosomotropic agents or brefeldin A had no effect on apoE recycling. Unlike previous results with hepatocytes and macrophages, neither apoA-I nor upregulation of ABCA1 stimulated apoE recycling. However, cyclodextrin, which extracts cholesterol from plasma membrane lipid rafts, increased recycling. Confocal studies revealed that apoE, internalized during a 1 h pulse, colocalizes with early endosomal antigen-1, Rab5, Rab11a, and lysobisphosphatidic acid but not with lysosomal-associated membrane protein-1. Colocalization of apoE and Rab11a persisted even after cells had been chased for 1 h, suggesting a pool of apoE within the endosomal recycling compartment (ERC). Our data suggest that apoE recycling in CHO cells is linked to cellular cholesterol removal via the ERC and phospholipid-containing acceptors in a pathway alternative to the ABCA1-apoA-I axis.

  2. Apolipoprotein E genotype and outcome in infants with hypoxic-ischemic encephalopathy.

    PubMed

    Cotten, C Michael; Goldstein, Ricki F; McDonald, Scott A; Goldberg, Ronald N; Salhab, Walid A; Carlo, Waldemar A; Tyson, Jon E; Finer, Neil N; Walsh, Michele C; Ehrenkranz, Richard A; Laptook, Abbot R; Guillet, Ronnie; Schibler, Kurt; Van Meurs, Krisa P; Poindexter, Brenda B; Stoll, Barbara J; O'Shea, T Michael; Duara, Shahnaz; Das, Abhik; Higgins, Rosemary D; Shankaran, Seetha

    2014-03-01

    Adults with the apolipoprotein E (APOE) gene alleles e4 and e2 are at high risk of poor neurological outcome after brain injury. The e4 allele has been associated with cerebral palsy (CP), and the e2 allele has been associated with worse neurological outcome with congenital heart disease. This study was done to test the hypothesis that the APOE genotype is associated with outcome among neonates who survive after hypoxic-ischemic encephalopathy (HIE). We conducted a cohort study of infants who survived HIE and had 18-22 mo standardized neurodevelopmental evaluations to assess associations between disability and the APOE genotypes e3/e3, e4/-, and e2/-. A total of 139 survivors were genotyped. Of these, 86 (62%) were of the e3/e3, 41 (29%) were of the e4/-, and 14 (10%) were of the e2/- genotypes. One hundred and twenty-nine infants had genotype and follow-up data; 26% had moderate or severe disabilities. Disability prevalence was 30 and 19% among those with and without the e3/e3 genotype, 25 and 26% among those with and without the e2 allele, and 18 and 29% among those with and without the e4 allele, respectively. None of the differences were statistically significant. CP prevalence was also similar among genotype groups. Disability was not associated with the APOE genotype in this cohort of HIE survivors.

  3. Apolipoprotein E in the genetics and epidemiology of Alzheimer`s disease

    SciTech Connect

    Hardy, J.

    1995-10-09

    The role of apolipoprotein E (ApoE) alleles and isoforms in the etiology and pathogenesis of Alzheimer`s disease is discussed. The possibility that ApoE itself is not involved in the disease pathogenesis but is merely in genetic disequilibrium with the real locus is discussed and dismissed. The data showing that the {epsilon}4 allele is associated with an increased risk of developing the disease and with an earlier onset age are reviewed. The data showing that, at least in some circumstances, the {epsilon}2 allele is associated with a decrease in the risk of developing the disease, and with a later onset age are also reviewed. Data from the genetic analysis of other disorders are reviewed and presented, and it is suggested that the genetic data support the notion that the role of ApoE in the etiology of the disease directly relates to {beta}-amyloid deposition and plaque formation. This suggestion is in concordance with the most likely mechanism for the role of P-amyloid precursor protein gene mutations as other risk factors for the disease. 68 refs.

  4. Relationship between the apolipoprotein E gene and headache following sports-related concussion.

    PubMed

    Merritt, Victoria C; Ukueberuwa, Dede M; Arnett, Peter A

    2016-11-01

    Headache is one of the most commonly reported and longest lasting symptoms that concussed athletes report, yet the etiology of headache symptoms following concussion is not entirely clear. The purpose of this study was to determine whether the e4 allele of the apolipoprotein E (APOE) gene influences the presence and severity of postconcussion headache. Participants were composed of 45 concussed athletes and 43 healthy/nonconcussed athletes who were involved in a clinically based sports concussion management program. All athletes completed the Post-Concussion Symptom Scale (PCSS). The "headache" symptom from the PCSS was the primary outcome variable. Buccal samples were collected and analyzed to determine APOE genotype. A significantly greater proportion of concussed e4+ athletes than e4- athletes endorsed headache. Furthermore, concussed e4+ athletes endorsed more severe headaches than e4- athletes. When examining the healthy/nonconcussed sample (i.e., athletes at baseline), results showed no differences between e4 allele groups with respect to the presence and severity of headache. These findings show that when compared to concussed e4- athletes, e4+ athletes are more likely to (a) endorse postconcussion headache and (b) report more severe headache symptoms following concussion. Conversely, it appears that the e4 allele does not influence baseline reports of headache. Thus, results suggest that those with the e4 genotype may be at a higher risk for experiencing headache-related difficulties only after a concussion is sustained.

  5. Apolipoprotein E ε4 genotype and the temporal relationship between depression and dementia

    PubMed Central

    Karlsson, Ida K.; Bennet, Anna M.; Ploner, Alexander; Andersson, Therese M.-L.; Reynolds, Chandra A.; Gatzc, Margaret; Pedersen, Nancy L.

    2015-01-01

    To investigate how apolipoprotein E (APOE) affects the temporal relationship between depression and dementia, we conducted a nested case-control study with longitudinal depression and dementia evaluations from several population studies, using 804 dementia cases and 1600 matched controls, totaling 1519 unique individuals. Depression within ten years of dementia onset was strongly associated with dementia diagnosis regardless of APOE status (IRR 5.25, 95%CI 3.32-8.31 for ε4 carriers, IRR 4.40, 95%CI 3.23-5.99 for non-carriers). However, we found a significant interaction between depression more than ten years prior to dementia onset and APOE (p=0.01), with depression more distal to dementia being a risk factor only in ε4 carriers (IRR 3.39, 95%CI 1.69-6.78 for carriers, IRR 1.01, 95%CI 0.60-1.70 for non-carriers). Thus, depression with onset close in time to dementia onset is associated with disease irrespective of APOE genotype, while depression more distal to dementia onset is a risk factor only in ε4-carriers. This is the first study to show the interaction between APOE and depression to be dependent on timing of depression onset. PMID:25670333

  6. Apolipoprotein E4 as a predictor of outcomes in pediatric mild traumatic brain injury.

    PubMed

    Moran, Lisa M; Taylor, H Gerry; Ganesalingam, Kalaichelvi; Gastier-Foster, Julie M; Frick, Jessica; Bangert, Barbara; Dietrich, Ann; Nuss, Kathryn E; Rusin, Jerome; Wright, Martha; Yeates, Keith O

    2009-09-01

    The epsilon4 allele of the apolipoprotein E (APOE) gene has been linked to negative outcomes among adults with traumatic brain injury (TBI) across the spectrum of severity, with preliminary evidence suggesting a similar pattern among children. This study investigated the relationship of the APOE epsilon4 allele to outcomes in children with mild TBI. Participants in this prospective, longitudinal study included 99 children with mild TBI between the ages of 8 and 15 recruited from consecutive admissions to Emergency Departments at two large children's hospitals. Outcomes were assessed acutely in the Emergency Department and at follow-ups at 2 weeks, 3 months, and 12 months post-injury. Among the 99 participants, 28 had at least one epsilon4 allele. Children with and without an epsilon4 allele did not differ demographically. Children with an epsilon4 allele were significantly more likely than those without an epsilon4 allele to have a Glasgow Coma Scale score of less than 15, but the groups did not differ on any other measures of injury severity. Those with an epsilon4 allele exhibited better performance than children without an epsilon4 allele on a test of constructional skill, but the groups did not differ on any other neuropsychological tests. Children with and without an epsilon4 allele also did not differ on measures of post-concussive symptoms. Overall, the findings suggest that the APOE epsilon4 allele is not consistently related to the outcomes of mild TBI in children.

  7. Apolipoprotein E (APOE) ϵ4 Allele Is Associated with Increased Symptom Reporting Following Sports Concussion.

    PubMed

    Merritt, Victoria C; Arnett, Peter A

    2016-01-01

    Exploring the relationship between genetic factors and outcome following brain injury has received increased attention in recent years. However, few studies have evaluated the influence of genes on specific sequelae of concussion. The purpose of this study was to determine how the ϵ4 allele of the apolipoprotein E (APOE) gene influences symptom expression following sports-related concussion. Participants included 42 collegiate athletes who underwent neuropsychological testing, including completion of the Post-Concussion Symptom Scale (PCSS), within 3 months after sustaining a concussion (73.8% were evaluated within 1 week). Athletes provided buccal samples that were analyzed to determine the make-up of their APOE genotype. Dependent variables included a total symptom score and four symptom clusters derived from the PCSS. Mann-Whitney U tests showed higher scores reported by athletes with the ϵ4 allele compared to those without it on the total symptom score and the physical and cognitive symptom clusters. Furthermore, logistic regression showed that the ϵ4 allele independently predicted those athletes who reported physical and cognitive symptoms following concussion. These findings illustrate that ϵ4+ athletes report greater symptomatology post-concussion than ϵ4- athletes, suggesting that the ϵ4 genotype may confer risk for poorer post-concussion outcome. (JINS, 2016, 22, 89-94).

  8. Apolipoprotein E4 Genotype Does Not Increase Risk of HIV-associated Neurocognitive Disorders

    PubMed Central

    Morgan, E.E.; Woods, S.P.; Letendre, S.L.; Franklin, D.R.; Bloss, C.; Goate, A.; Heaton, R.K.; Collier, A.C.; Marra, C.M.; Gelman, B.B.; McArthur, J.C.; Morgello, S.; Simpson, D.M.; McCutchan, J.A.; Ellis, R.J.; Abramson, I.; Gamst, A.; Fennema-Notestine, C.; Smith, D.M.; Grant, I.; Vaida, F.; Clifford, D.B.

    2013-01-01

    This is a cross-sectional, observational study to evaluate the hypothesis that HIV-seropositive (HIV+) apolipoprotein E4 (APOE4) carriers are at increased risk for HIV-associated Neurocognitive Disorders (HAND) compared to APOE4 noncarriers with HIV in the CNS HIV Antiretroviral Therapy Effects Research (CHARTER) Group sample. APOE genotype was determined in 466 CHARTER participants with varying disease stages and histories of antiretroviral treatment who did not have severe psychiatric or medical comorbid conditions that preclude diagnosis of HAND. HAND diagnoses were based on results of comprehensive neurobehavioral evaluation and use of current neuroAIDS diagnostic criteria. HAND status consisting of two levels: neuropsychologically normal status (i.e., no HAND) and any HAND diagnosis (i.e., asymptomatic neurocognitive impairment, minor neurocognitive disorder, HIV-associated dementia). Logistic regression analyses revealed no association between APOE4 carrier status and HAND, and there were no interactions between APOE4 carrier status and ethnicity, age, substance use disorders, duration of infection, or nadir CD4. Results did not differ when analysis was restricted to symptomatic HAND, and no APOE4 gene dose-dependent relationship to HAND emerged. APOE4 status was not associated with concurrent HAND in this large, well-characterized sample. This does not preclude emergence of an association between APOE4 status and HAND as this population ages. Prospective, longitudinal studies are needed to examine APOE4 as a risk factor for neurocognitive decline, incident HAND at older ages, and potential associations with CSF amyloid. PMID:23408335

  9. Propositional Density and Apolipoprotein E Genotype among Persons at Risk for Familial Alzheimer's Disease

    PubMed Central

    Medina, Luis D.; Rodriguez-Agudelo, Yaneth; Geschwind, Daniel H.; Gilbert, Paul E.; Liang, Li-Jung; Cummings, Jeffrey L.; Ringman, John M.

    2011-01-01

    Background/Aims A relationship between decreased propositional density (p-density) in young adulthood and future risk for Alzheimer's disease (AD) has been postulated, but multiple interpretations of the nature of this relationship are possible. This study explored the relationship between familial AD (FAD) mutation status, apolipoprotein E (APOE) genotype, and p-density. Methods Thirty-five non-demented persons at risk for FAD mutations were recruited. Subjects wrote brief biographical essays from which p-density, the ratio of the number of unique ideas to the number of words in the text, was calculated. Mixed-effects regression models were used to examine the relationship of p-density and FAD mutation status and APOE genotype. Results FAD mutation status was not significantly associated with p-density. However, results from both models indicated that the presence of the APOE ∊4 allele was significantly associated with p-density (p < 0.0001), with APOE ∊4 carriers having lower p-density than non-carriers. Conclusions Our results are consistent with an influence of APOE status on p-density in young adulthood that is independent of the AD risk per se and suggest the previous finding of increased risk for the development of AD in persons with decreased p-density may be related to APOE genotype. PMID:22134129

  10. Apolipoprotein E Genotype and Cognitive Function in Postmenopausal Women With Early-Stage Breast Cancer

    PubMed Central

    Koleck, Theresa A.; Bender, Catherine M.; Sereika, Susan M.; Ahrendt, Gretchen; Jankowitz, Rachel C.; McGuire, Kandace P.; Ryan, Christopher M.; Conley, Yvette P.

    2015-01-01

    Purpose/Objectives To examine the role of apolipoprotein E (APOE) genotype in the cognitive function of post-menopausal women with early-stage breast cancer prior to initiation of adjuvant therapy and over time with treatment. Design Longitudinal, genetic association study. Setting Urban university cancer center. Sample Three cohorts of postmenopausal women: 37 women with breast cancer receiving chemotherapy and anastrozole, 41 women with breast cancer receiving anastrozole alone, and 50 healthy women. Methods Cognitive function was evaluated three times during a 12-month period using a comprehensive neuropsychological test battery. Participants were genotyped and classified based on the presence or absence of at least one APOE ε4 allele. Multiple linear regression was used to determine if APOE genotype accounted for observed variability in cognitive function data. Main Research Variables APOE genotype, breast cancer treatment, and cognitive function. Findings Performance or changes in performance on tasks of executive function, attention, verbal learning and memory, and visual learning and memory were found to be influenced by APOE genotype and/or interactions between APOE genotype and study cohort. Conclusions The results indicate that cognitive function in postmenopausal women with breast cancer is modified by APOE genotype and the combination of APOE genotype and treatment. Implications for Nursing APOE genotype, along with other biomarkers, may be used in the future to assist nurses in identifying women with breast cancer most at risk for cognitive decline. PMID:25355028

  11. Longitudinal Trajectories of Cholesterol from Midlife through Late Life according to Apolipoprotein E Allele Status

    PubMed Central

    Downer, Brian; Estus, Steven; Katsumata, Yuriko; Fardo, David W.

    2014-01-01

    Background: Previous research indicates that total cholesterol levels increase with age during young adulthood and middle age and decline with age later in life. This is attributed to changes in diet, body composition, medication use, physical activity, and hormone levels. In the current study we utilized data from the Framingham Heart Study Original Cohort to determine if variations in apolipoprotein E (APOE), a gene involved in regulating cholesterol homeostasis, influence trajectories of total cholesterol, HDL cholesterol, and total: HDL cholesterol ratio from midlife through late life. Methods: Cholesterol trajectories from midlife through late life were modeled using generalized additive mixed models and mixed-effects regression models. Results: APOE e2+ subjects had lower total cholesterol levels, higher HDL cholesterol levels, and lower total: HDL cholesterol ratios from midlife to late life compared to APOE e3 and APOE e4+ subjects. Statistically significant differences in life span cholesterol trajectories according to gender and use of cholesterol-lowering medications were also detected. Conclusion: The findings from this research provide evidence that variations in APOE modify trajectories of serum cholesterol from midlife to late life. In order to efficiently modify cholesterol through the life span, it is important to take into account APOE allele status. PMID:25325355

  12. Subcellular distribution of apolipoprotein E along the lipoprotein synthetic pathway of rat liver

    SciTech Connect

    Cole, T.G.; Stockhausen, D.C.

    1986-03-01

    Apolipoprotein E (apoE) is synthesized by the liver and is secreted as a component of VLDL. To define the intracellular locations of apoE, liver from 10 nonfasted male rats were removed and subcellular organelles prepared by differential pelleting through sucrose gradients. Mass of apoE was measured by radioimmunoassay. Approximately 10% of total hepatic apoE was recovered in rough endoplasmic reticulum (RER), smooth endoplasmic reticulum (SER) and Golgi fractions. Concentrations of apoE (ng/mg protein) were: homogenate, 302 +/- 59; RER, 653 +/- 251; SER, 1250 +/- 471; Golgi, 11,044 +/- 4291. Total apoE content of each reaction (..mu..g/organelle) was: homogenate (whole liver), 517 +/- 103; RER, 15 +/- 3; SER, 9 +/- 3; Golgi, 28 +/- 8. These data indicate that along the putative pathway of lipoprotein synthesis (RER->SER->Golgi), apoE concentration increases in each successive organelle and that flux of apoE is apparently most rapid through SER. Furthermore, the majority of apoE in the rat liver is apparently not directly associated with the lipoprotein synthetic pathway and may be associated with internalized lipoproteins or may be involved in non-lipoprotein related functions.

  13. Apolipoprotein E-Mimetic COG1410 Reduces Acute Vasogenic Edema following Traumatic Brain Injury

    PubMed Central

    Cao, Fang; Wu, Yue; Zhong, Jianjun; Liu, Jieshi; Qin, Xinghu; Chen, Ligang; Vitek, Michael P.; Li, Fengqiao; Xu, Lu

    2016-01-01

    Abstract The degree of post-traumatic brain edema and dysfunction of the blood–brain barrier (BBB) influences the neurofunctional outcome after a traumatic brain injury (TBI). Previous studies have demonstrated that the administration of apolipoprotein E-mimetic peptide COG1410 reduces the brain water content after subarachnoid hemorrhage, intra-cerebral hemorrhage, and focal brain ischemia. However, the effects of COG1410 on vasogenic edema following TBI are not known. The current study evaluated the effects of 1 mg/kg daily COG1410 versus saline administered intravenously after a controlled cortical impact (CCI) injury on BBB dysfunction and vasogenic edema at an acute stage in mice. The results demonstrated that treatment with COG1410 suppressed the activity of matrix metalloproteinase-9, reduced the disruption of the BBB and Evans Blue dye extravasation, reduced the TBI lesion volume and vasogenic edema, and decreased the functional deficits compared with mice treated with vehicle, at an acute stage after CCI. These findings suggest that COG1410 is a promising preclinical therapeutic agent for the treatment of traumatic brain injury. PMID:26192010

  14. An Apolipoprotein E-Mimetic Stimulates Axonal Regeneration and Remyelination after Peripheral Nerve Injury

    PubMed Central

    Fowler, Kenneth A.; Neil, Jessica E.; Colton, Carol A.; Vitek, Michael P.

    2010-01-01

    Elevated apolipoprotein E (apoE) synthesis within crushed sciatic nerves advocates that apoE could benefit axonal repair and reconstruction of axonal and myelin membranes. We created an apoE-mimetic peptide, COG112 (acetyl-RQIKIWFQNRRMKWKKCLRVRLASHLRKLRKRLL-amide), and found that postinjury treatment with COG112 significantly improved recovery of motor and sensory function following sciatic nerve crush in C57BL/6 mice. Morphometric analysis of injured sciatic nerves revealed that COG112 promoted axonal regrowth after 2 weeks of treatment. More strikingly, the thickness of myelin sheaths was increased by COG112 treatment. Consistent with these histological findings, COG112 potently elevated growth associated protein 43 (GAP-43) and peripheral myelin protein zero (P0), which are markers of axon regeneration and remyelination, respectively. Electron microscopic examination further suggested that the apoE-mimetic COG112 may increase clearance of myelin debris. Schwann cell uptake of cholesterol-containing low-density lipoprotein particles was selectively enhanced by COG112 treatment in a Schwann cell line S16. Moreover, COG112 significantly promoted axon elongation in primary dorsal root ganglion cultures from rat pups. Considering that cholesterol and lipids are needed for reconstructing myelin sheaths and axon extension, these data support a hypothesis where supplementation with exogenous apoE-mimetics such as COG112 may be a promising strategy for restoring lost functional and structural elements following nerve injury. PMID:20406857

  15. Association of apolipoprotein E genotype and Alzheimer disease in African Americans.

    PubMed

    Murrell, Jill R; Price, Brandon; Lane, Kathleen A; Baiyewu, Olusegun; Gureje, Oye; Ogunniyi, Adesola; Unverzagt, Frederick W; Smith-Gamble, Valerie; Gao, Sujuan; Hendrie, Hugh C; Hall, Kathleen S

    2006-03-01

    Alzheimer disease (AD) is the most frequent cause of dementia. Even though the incidence of AD in the African American population is similar to or higher than that in persons of European descent, AD in African Americans is understudied. Identification of genetic risk factors in African Americans is essential for understanding the etiology of AD. To determine the effect of apolipoprotein E (APOE) genotype on the risk of AD in elderly African Americans. Population-based longitudinal study of AD. Indianapolis, Ind. African Americans 65 years and older. APOE genotype and diagnosis of AD. The APOE genotype was determined in 1822 samples. Of these, 690 were clinically evaluated: 318 were normal, and 162 had a diagnosis of AD. The presence of APOE epsilon4 was significantly associated with increased risk of AD (epsilon3/epsilon4: OR, 2.32; 95% confidence interval [CI], 1.41-3.82; and epsilon4/epsilon4: OR, 7.19; 95% CI, 3.00-17.29, compared with the epsilon3/epsilon3 genotype). There was also a significant protective effect with APOE epsilon2 (epsilon2/epsilon2 and epsilon2/epsilon3: OR, 0.42; 95% CI, 0.20-0.89). These findings are in marked contrast to the lack of association between APOE and AD in the Ibadan, Nigeria, sample of this project. These results suggest that other genetic factors and different environmental influences may play a role in the risk for AD in individuals of African ancestry.

  16. Apolipoprotein E polymorphism and age at onset of Alzheimer's disease in a quadriethnic sample.

    PubMed

    Kwon, Oh Dae; Khaleeq, Aisha; Chan, Wenyaw; Pavlik, Valory N; Doody, Rachelle S

    2010-01-01

    The relationship between the apolipoprotein E (ApoE) genotype and the risk for developing Alzheimer's disease (AD) or age at onset of AD is relatively well established in Caucasians, but less established in other ethnicities. We examined the association between the ApoE genotype and age at onset of AD in a quadriethnic group of community-dwelling AD patients. AD patients were evaluated at 2 university-based outpatient memory disorder clinics. The ethnic distribution was as follows: Caucasians (n = 1,083), Hispanics (n = 55), African Americans (n = 84) and Koreans (n = 87). All were diagnosed with probable AD according to NINCDS-ADRDA diagnostic criteria. After adjusting for ethnicity, the ε4 allele was significantly associated with earlier age at onset (p < 0.0001) for the combined group. Within ethnic groups, the effect of Apo ε4 on age at onset was significant in Caucasians (p < 0.0001) and African Americans (p < 0.05), but nonsignificant in Koreans (p = 0.43) and in the smaller Hispanic (p = 0.07) group. The association between Apo ε4 and younger age at onset was significant in Caucasians and African Americans, where the ε4 allele was also most frequent. This study suggests that the impact of ApoE polymorphism on age at onset of AD may be different among distinct ethnic groups. Copyright © 2011 S. Karger AG, Basel.

  17. Heredity links natural hazards and human health: Apolipoprotein E gene moderates the health of earthquake survivors.

    PubMed

    Daly, Michael; MacLachlan, Malcolm

    2011-03-01

    This study aimed to investigate the role of the apolipoprotein ε4 allele in moderating the influence of an exogenous stressor, an earthquake, on health. A "natural experiment" design was used where the interaction between the presence of the apolipoprotein ε4 allele and the level of subjective and objective exposure to a devastating earthquake was examined in a population-based cohort of elderly Taiwanese (N = 718). The cognitive-affective dimension of health was assessed by measures of perceived control and depression and functional limitations were assessed using measures of instrumental activities of daily living and mobility. Overall health status was gauged using a single-item measure of self-rated health. Those who experienced damage to their property or were forced to move from their homes (high objective exposure) demonstrated low levels of self-rated health and somewhat lower perceived control a year later, only if they were apolipoprotein ε4 carriers. Similarly, those who found the earthquake severely distressing (high subjective exposure) were shown to have low levels of functioning and low self-rated health a year later, only if they possessed the ε4 allele. Our findings suggest that genetic variation in the apolipoprotein E gene may modify the health effects of the exogenous stress of natural disaster exposure.

  18. Immunolocalization of an amino-terminal fragment of apolipoprotein E in the Pick's disease brain.

    PubMed

    Rohn, Troy T; Day, Ryan J; Catlin, Lindsey W; Brown, Raquel J; Rajic, Alexander J; Poon, Wayne W

    2013-01-01

    Although the risk factor for apolipoprotein E (apoE) polymorphism in Alzheimer's disease (AD) has been well described, the role that apoE plays in other neurodegenerative diseases, including Pick's disease, is not well established. To examine a possible role of apoE in Pick's disease, an immunohistochemical analysis was performed utilizing a novel site-directed antibody that is specific for an amino-terminal fragment of apoE. Application of this antibody, termed the amino-terminal apoE cleavage fragment (nApoECF) antibody, consistently labeled Pick bodies within area CA1 of the hippocampus in 4 of the 5 cases examined. Co-localization of the nApoECF antibody with PHF-1, a general marker for Pick bodies, as well as with an antibody to caspase-cleaved tau (TauC3) was evident within the hippocampus. While staining of the nApoECF antibody was robust in area CA1, little co-localization with PHF-1 in Pick bodies within the dentate gyrus was observed. A quantitative analysis indicated that approximately 86% of the Pick bodies identified in area CA1 labeled with the nApoECF antibody. The presence of truncated apoE within Pick bodies suggests a broader role of apoE beyond AD and raises the question as to whether this protein contributes to pathogenesis associated with Pick's disease.

  19. The Complex Role of Apolipoprotein E in Alzheimer's Disease: an Overview and Update.

    PubMed

    Mahoney-Sanchez, Laura; Belaidi, Abdel Ali; Bush, Ashley I; Ayton, Scott

    2016-11-01

    Apolipoprotein E (ApoE) plays a crucial role in the homeostatic control of lipids in both the periphery and the central nervous system (CNS). In humans, ApoE exists in three different isoforms: ε2, ε3 and ε4. ApoE ε3 is the most common isoform, while the ε4 isoform confers the greatest genetic risk for Alzheimer's disease (AD). However, the mechanisms underlying how ApoE contributes to the pathogenesis of AD are still debated. ApoE has been shown to impact amyloid β (Aβ) deposition and clearance in the brain. ApoE also has Aβ-independent pathways in AD, which has led to the discovery of new roles of ApoE ranging from mitochondria dysfunction to, most recently, iron metabolism. Here, we review the role of ApoE in health and in AD, with the view of identifying therapeutic approaches that could prevent the risk associated with the ε4 isoform.

  20. Coronary artery disease and plasma apolipoprotein E4 in mild cognitive impairment

    PubMed Central

    Barekatain, Majid; Zahedian, Faezeh; Askarpour, Hedyeh; Maracy, Mohammad Reza; Hashemi-Jazi, Mohammad; Aghaye-Ghazvini, Mohammad Reza

    2014-01-01

    BACKGROUND Atherosclerosis and apolipoprotein E4 (APOE4) are known risks for Dementia. We sought to evaluate the relationship between coronary atherosclerosis and APOE4 with mild cognitive impairment (MCI). METHODS In a case-control study, subjects with age more than 60 years and recent coronary angiography were evaluated by mini-mental state examination and neuropsychiatry unit cognitive assessment tool (NUCOG) to find the patients with MCI (n = 40) and the controls with normal cognition (n = 40). Coronary angiography records were re-assessed to find the severity of coronary artery disease by the Gensini scores. Plasma levels of APOE4 were measured. RESULTS There were no-significant difference between the 2 groups regarding the plasma APOE4 levels (P = 0.706) and the Gensini scores (P = 0.236). Associations between the Gensini scores and the NUCOG scores in the MCI group (r = −0.196, P = 0.225) and the control group (r = 0.189, P = 0.243) were not significant. However, the interaction effect between the Gensini and the NUCOG scores based on allocation to the control or the patient groups showed statistically significant difference (F(1,67) = 4.84, P = 0.031). CONCLUSION Although atherosclerosis has been considered as known risk factor for dementia and MCI, this study could not reveal that coronary atherosclerosis-related to declining in cognitive functioning. There was no significant association between plasma APOE4 levels and MCI. PMID:25477981

  1. Exercise training reduces severity of atherosclerosis in apolipoprotein E knockout mice via nitric oxide.

    PubMed

    Shimada, Kana; Kishimoto, Chiharu; Okabe, Taka-aki; Hattori, Miki; Murayama, Toshinori; Yokode, Masayuki; Kita, Toru

    2007-07-01

    Exercise training may protect against the development of atherosclerosis, although the precise mechanisms are still unknown. The present study assessed the hypothesis that exercise training would reduce the severity of experimental atherosclerosis in apolipoprotein-E (apoE)-deficient mice via nitric oxide (NO). ApoE-deficient mice fed a high-fat diet underwent exercise training (30 min swimming) 3 times per week for 8 weeks. The exercise group were also given oral N(G)-nitro-L-arginine methylester (L-NAME; 25 mg x kg (-1) x day(-1)), an inhibitor of NO synthase. Fatty streak plaque lesions developed in ApoE-deficient mice fed the high-fat diet, and were suppressed in the mice that underwent swimming training. In contrast, atherosclerotic lesions were not ameliorated in mice that had exercise training plus oral L-NAME treatment. Immunohistochemical analysis revealed that the expression of endothelial NO increased in mice undergoing exercise compared with the mice that did not exercise, and that the expression was suppressed in the mice having exercise plus oral L-NAME treatment. Differences in lesion area did not correlate with any significant alterations in serum lipid levels. Exercise training suppressed atherosclerosis via the NO system.

  2. Expression of apolipoprotein E by cultured vascular smooth muscle cells is controlled by growth state

    PubMed Central

    1988-01-01

    Rat vascular smooth muscle cells (SMC) in culture synthesize and secrete a approximately 38,000-Mr protein doublet or triplet that, as previously described (Majack and Bornstein. 1984. J. Cell Biol. 99:1688- 1695), rapidly and reversibly accumulates in the SMC culture medium upon addition of heparin. In the present study, we show that this approximately 38,000-Mr heparin-regulated protein is electrophoretically and immunologically identical to apolipoprotein E (apo-E), a major plasma apolipoprotein involved in cholesterol transport. In addition, we show that expression of apo-E by cultured SMC varies according to growth state: while proliferating SMC produced little apo-E and expressed low levels of apo-E mRNA, quiescent SMC produced significantly more apo-E (relative to other proteins) and expressed markedly increased levels of apo-E mRNA. Northern analysis of RNA extracted from aortic tissue revealed that fully differentiated, quiescent SMC contain significant quantities of apo-E mRNA. These data establish aortic SMC as a vascular source for apo-E and suggest new functional roles for this apolipoprotein, possibly unrelated to traditional concepts of lipid metabolism. PMID:2458361

  3. Allergic lung inflammation promotes atherosclerosis in apolipoprotein E-deficient mice.

    PubMed

    Liu, Cong-Lin; Wang, Yi; Liao, Mengyang; Santos, Marcela M; Fernandes, Cleverson; Sukhova, Galina K; Zhang, Jin-Ying; Cheng, Xiang; Yang, Chongzhe; Huang, Xiaozhu; Levy, Bruce; Libby, Peter; Wu, Gongxiong; Shi, Guo-Ping

    2016-05-01

    Inflammation drives asthma and atherosclerosis. Clinical studies suggest that asthmatic patients have a high risk of atherosclerosis. Yet this hypothesis remains uncertain, given that Th2 imbalance causes asthma whereas Th1 immunity promotes atherosclerosis. In this study, chronic allergic lung inflammation (ALI) was induced in mice by ovalbumin sensitization and challenge. Acute ALI was induced in mice by ovalbumin and aluminum sensitization and ovalbumin challenge. Atherosclerosis was produced in apolipoprotein E-deficient (Apoe(-/-)) mice with a Western diet. When chronic ALI and atherosclerosis were produced simultaneously, ALI increased atherosclerotic lesion size, lesion inflammatory cell content, elastin fragmentation, smooth muscle cell (SMC) loss, lesion cell proliferation, and apoptosis. Production of acute ALI before atherogenesis did not affect lesion size, but increased atherosclerotic lesion CD4(+) T cells, lesion SMC loss, angiogenesis, and apoptosis. Production of acute ALI after atherogenesis also did not change atherosclerotic lesion area, but increased lesion elastin fragmentation, cell proliferation, and apoptosis. In mice with chronic ALI and diet-induced atherosclerosis, daily inhalation of a mast cell inhibitor or corticosteroid significantly reduced atherosclerotic lesion T-cell and mast cell contents, SMC loss, angiogenesis, and cell proliferation and apoptosis, although these drugs did not affect lesion area, compared with those that received vehicle treatment. In conclusion, both chronic and acute ALI promote atherogenesis or aortic lesion pathology, regardless whether ALI occurred before, after, or at the same time as atherogenesis. Antiasthmatic medication can efficiently mitigate atherosclerotic lesion pathology.

  4. Cellular Source of Apolipoprotein E4 Determines Neuronal Susceptibility to Excitotoxic Injury in Transgenic Mice

    PubMed Central

    Buttini, Manuel; Masliah, Eliezer; Yu, Gui-Qiu; Palop, Jorge J.; Chang, Shengjun; Bernardo, Aubrey; Lin, Carol; Wyss-Coray, Tony; Huang, Yadong; Mucke, Lennart

    2010-01-01

    The lipid transport protein apolipoprotein E (apoE) is abundantly expressed in the brain. Its main isoforms in humans are apoE2, apoE3, and apoE4. ApoE4 is the major known genetic risk factor for Alzheimer’s disease and also contributes to the pathogenesis of various other neurological conditions. In the central nervous system, apoE is synthesized by glial cells and neurons, but it is unclear whether the cellular source affects its biological activities. To address this issue, we induced excitotoxic injury by systemic kainic acid injection in transgenic Apoe knockout mice expressing human apoE isoforms in astrocytes or neurons. Regardless of its cellular source, apoE3 expression protected neuronal synapses and dendrites against the excitotoxicity seen in apoE-deficient mice. Astrocyte-derived apoE4, which has previously been shown to have detrimental effects in vitro, was as excitoprotective as apoE3 in vivo. In contrast, neuronal expression of apoE4 was not protective and resulted in loss of cortical neurons after excitotoxic challenge, indicating that neuronal apoE4 promotes excitotoxic cell death. Thus, an imbalance between astrocytic (excitoprotective) and neuronal (neurotoxic) apoE4 expression may increase susceptibility to diverse neurological diseases involving excitotoxic mechanisms. PMID:20595630

  5. Cellular source of apolipoprotein E4 determines neuronal susceptibility to excitotoxic injury in transgenic mice.

    PubMed

    Buttini, Manuel; Masliah, Eliezer; Yu, Gui-Qiu; Palop, Jorge J; Chang, Shengjun; Bernardo, Aubrey; Lin, Carol; Wyss-Coray, Tony; Huang, Yadong; Mucke, Lennart

    2010-08-01

    The lipid transport protein apolipoprotein E (apoE) is abundantly expressed in the brain. Its main isoforms in humans are apoE2, apoE3, and apoE4. ApoE4 is the major known genetic risk factor for Alzheimer's disease and also contributes to the pathogenesis of various other neurological conditions. In the central nervous system, apoE is synthesized by glial cells and neurons, but it is unclear whether the cellular source affects its biological activities. To address this issue, we induced excitotoxic injury by systemic kainic acid injection in transgenic Apoe knockout mice expressing human apoE isoforms in astrocytes or neurons. Regardless of its cellular source, apoE3 expression protected neuronal synapses and dendrites against the excitotoxicity seen in apoE-deficient mice. Astrocyte-derived apoE4, which has previously been shown to have detrimental effects in vitro, was as excitoprotective as apoE3 in vivo. In contrast, neuronal expression of apoE4 was not protective and resulted in loss of cortical neurons after excitotoxic challenge, indicating that neuronal apoE4 promotes excitotoxic cell death. Thus, an imbalance between astrocytic (excitoprotective) and neuronal (neurotoxic) apoE4 expression may increase susceptibility to diverse neurological diseases involving excitotoxic mechanisms.

  6. Apolipoprotein E e4 Allele is Associated with More Rapid Motor Decline in Older Persons

    PubMed Central

    Buchman, Aron S.; Boyle, Patricia A.; Wilson, Robert S.; Beck, Todd L.; Kelly, Jeremiah F.; Bennett, David A.

    2008-01-01

    We tested the hypothesis that apolipoprotein E allele status predicts the rate of motor decline in the elderly. 876 older participants without dementia underwent baseline and annual motor testing for up to 10 years. In a generalized estimating equation controlling for age, sex and education, motor function declined by about 0.03 unit/year. The presence of ε4 allele was associated with a two-fold increase in rate of motor decline [ε4 allele × Time: Estimate= −0.027 (S.E. 0.012, p=0.025)]. The association of ε4 allele with motor decline persisted even after controlling for cognitive status, race, BMI, vascular risk factors and diseases. Further analyses suggested that the association of ε4 with motor decline was for the most part explained by the association between ε4 allele with change in muscle strength. These results suggest that the presence of ε4 allele is a risk factor for more rapid motor decline in the elderly. PMID:19266700

  7. Iron-ion radiation accelerates atherosclerosis in apolipoprotein E-deficient mice.

    PubMed

    Yu, Tao; Parks, Brian W; Yu, Shaohua; Srivastava, Roshni; Gupta, Kiran; Wu, Xing; Khaled, Saman; Chang, Polly Y; Kabarowski, Janusz H; Kucik, Dennis F

    2011-06-01

    Radiation exposure from a number of terrestrial sources is associated with an increased risk for atherosclerosis. Recently, concern over whether exposure to cosmic radiation might pose a similar risk for astronauts has increased. To address this question, we examined the effect of 2 to 5 Gy iron ions ((56)Fe), a particularly damaging component of cosmic radiation, targeted to specific arterial sites in male apolipoprotein E-deficient (apoE(-/-)) mice. Radiation accelerated the development of atherosclerosis in irradiated portions of the aorta independent of any systemic effects on plasma lipid profiles or circulating leukocytes. Further, radiation exposure resulted in a more rapid progression of advanced aortic root lesions, characterized by larger necrotic cores associated with greater numbers of apoptotic macrophages and reduced lesional collagen compared to sham-treated mice. Intima media thickening of the carotid arteries was also exacerbated. Exposure to (56)Fe ions can therefore accelerate the development of atherosclerotic lesions and promote their progression to an advanced stage characterized by compositional changes indicative of increased thrombogenicity and instability. We conclude that the potential consequences of radiation exposure for astronauts on prolonged deep-space missions are a major concern. Knowledge gained from further studies with animal models should lead to a better understanding of the pathophysiological effects of accelerated ion radiation to better estimate atherogenic risk and develop appropriate countermeasures to mitigate its damaging effects.

  8. Akt isoform-dependent regulation of ATP-Binding cassette A1 expression by apolipoprotein E.

    PubMed

    Okoro, Emmanuel U; Guo, Zhongmao; Yang, Hong

    2016-08-12

    We previously reported that apolipoprotein E (apoE) upregulates ATP-binding cassette transporter A1 (ABCA1) transcription through phosphatidylinositol 3-kinase (PI3K). Here we demonstrate that treatment of murine macrophages with human apoE3 enhanced Akt phosphorylation, and upregulated ABCA1 protein and mRNA expression. Inhibition of PI3K weakened apoE3-induced Akt phosphorylation, and ABCA1 protein and mRNA increase. In contrast, inhibition of Akt only diminished apoE-induced ABCA1 protein but not the mRNA level. Suppression of protein synthesis did not erase the ability of apoE3 to increase ABCA1 protein level. Further, apoE3 increased the resistance of ABCA1 protein to calpain-mediated degradation without affecting calpain activity. Treatment of macrophages with apoE3 selectively enhanced the phosphorylation of Akt1 and Akt2, but not Akt3. Knockdown of Akt1 or Akt2 increased and decreased ABCA1 protein level, respectively; while overexpression of these Akt isoenzymes caused changes in ABCA1 protein level opposite to those induced by knockdown of the corresponding Akt. These data imply that apoE3 guards against calpain-mediated ABCA1 degradation through Akt2.

  9. IL-20 is expressed in atherosclerosis plaques and promotes atherosclerosis in apolipoprotein E-deficient mice.

    PubMed

    Chen, Wei-Yu; Cheng, Bor-Chih; Jiang, Meei-Jyh; Hsieh, Mei-Yi; Chang, Ming-Shi

    2006-09-01

    Atherosclerosis is a chronic inflammatory disease with immune cell infiltration. Various cytokines and chemokines have been characterized as pro- or antiatherogenic factors. Interleukin-20 (IL-20) belongs to the IL-10 family and is a proinflammatory cytokine involved in the pathogenesis of psoriasis. However, the association between IL-20 and atherosclerosis is undetermined. Therefore, we sought to investigate whether IL-20 is associated with atherosclerosis. We examined the expression of IL-20 and its receptor complex IL-20R1/IL-20R2 in atherosclerotic lesions of humans and mice using immunohistochemical staining. IL-20 was expressed in macrophage-rich areas. Both IL-20 and IL-20R1/IL-20R2 were expressed by endothelial cells lining the intimal microvessels, vasa vasorum, but rarely in nonatherosclerotic arteries. We used reverse-transcription polymerase chain reaction to analyze gene expression. IL-20 transcripts increased in hypoxic monocytes and monocytes treated with oxidized low-density lipoprotein. The expression of IL-20R1 and IL-20R2 was also upregulated by human umbilical vein endothelial cells in response to hypoxic treatment. Incubating IL-20 with human umbilical vein endothelial cells upregulated CXCL9 and CXCL11 transcripts. Furthermore, in vivo administration of IL-20 expression vector using intramuscular electroporation promoted atherosclerosis in apolipoprotein E-deficient mice. Our data suggest that IL-20 is a proatherogenic cytokine that contributes to the progression of atherosclerosis.

  10. Increased sensitivity of apolipoprotein E knockout mice to copper-induced oxidative injury to the liver.

    PubMed

    Chen, Yuan; Li, Bin; Zhao, Ran-ran; Zhang, Hui-feng; Zhen, Chao; Guo, Li

    2015-04-10

    Apolipoprotein E (ApoE) genotypes are related to clinical presentations in patients with Wilson's disease, indicating that ApoE may play an important role in the disease. However, our understanding of the role of ApoE in Wilson's disease is limited. High copper concentration in Wilson's disease induces excessive generation of free oxygen radicals. Meanwhile, ApoE proteins possess antioxidant effects. We therefore determined whether copper-induced oxidative damage differ in the liver of wild-type and ApoE knockout (ApoE(-/-)) mice. Both wild-type and ApoE(-/-) mice were intragastrically administered with 0.2 mL of copper sulfate pentahydrate (200 mg/kg; a total dose of 4 mg/d) or the same volume of saline daily for 12 weeks, respectively. Copper and oxidative stress markers in the liver tissue and in the serum were assessed. Our results showed that, compared with the wild-type mice administered with copper, TBARS as a marker of lipid peroxidation, the expression of oxygenase-1 (HO-1), NAD(P)H dehydrogenase, and quinone 1 (NQO1) significantly increased in the ApoE(-/-) mice administered with copper, meanwhile superoxide dismutase (SOD) activity significantly decreased. Thus, it is concluded that ApoE may protect the liver from copper-induced oxidative damage in Wilson's disease.

  11. 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.

  12. Can gallium dimer react effectively with three H 2 molecules to form digallane?

    NASA Astrophysics Data System (ADS)

    Moc, Jerzy

    2005-06-01

    Distinct routes of formation of digallane (4) Ga 2H 4 and digallane (6) Ga 2H 6 starting with gallium atoms/H 2 and gallium dimers/H 2 are compared based on the high level ab initio single-reference CCSD(T) and CASSCF based SOCI and hybrid density functional theory calculations of the mechanisms involved. The predicted reaction paths are of relevance to the recent matrix IR studies on the gallium hydrides, notably the extensive one by Wang and Andrews [X. Wang, L. Andrews, J. Phys. Chem. A 107 (2003) 11371] who isolated and assigned the series of mono- and digallium hydrides including the two digallanes.

  13. The Four Canonical TPR Subunits of Human APC/C Form Related Homo-Dimeric Structures and Stack in Parallel to Form a TPR Suprahelix☆

    PubMed Central

    Zhang, Ziguo; Chang, Leifu; Yang, Jing; Conin, Nora; Kulkarni, Kiran; Barford, David

    2013-01-01

    The anaphase-promoting complex or cyclosome (APC/C) is a large E3 RING-cullin ubiquitin ligase composed of between 14 and 15 individual proteins. A striking feature of the APC/C is that only four proteins are involved in directly recognizing target proteins and catalyzing the assembly of a polyubiquitin chain. All other subunits, which account for > 80% of the mass of the APC/C, provide scaffolding functions. A major proportion of these scaffolding subunits are structurally related. In metazoans, there are four canonical tetratricopeptide repeat (TPR) proteins that form homo-dimers (Apc3/Cdc27, Apc6/Cdc16, Apc7 and Apc8/Cdc23). Here, we describe the crystal structure of the N-terminal homo-dimerization domain of Schizosaccharomyces pombe Cdc23 (Cdc23Nterm). Cdc23Nterm is composed of seven contiguous TPR motifs that self-associate through a related mechanism to those of Cdc16 and Cdc27. Using the Cdc23Nterm structure, we generated a model of full-length Cdc23. The resultant “V”-shaped molecule docks into the Cdc23-assigned density of the human APC/C structure determined using negative stain electron microscopy (EM). Based on sequence conservation, we propose that Apc7 forms a homo-dimeric structure equivalent to those of Cdc16, Cdc23 and Cdc27. The model is consistent with the Apc7-assigned density of the human APC/C EM structure. The four canonical homo-dimeric TPR proteins of human APC/C stack in parallel on one side of the complex. Remarkably, the uniform relative packing of neighboring TPR proteins generates a novel left-handed suprahelical TPR assembly. This finding has implications for understanding the assembly of other TPR-containing multimeric complexes. PMID:23583778

  14. MDA5 cooperatively forms dimers and ATP-sensitive filaments upon binding double-stranded RNA

    PubMed Central

    Berke, Ian C; Modis, Yorgo

    2012-01-01

    Melanoma differentiation-associated gene-5 (MDA5) detects viral double-stranded RNA in the cytoplasm. RNA binding induces MDA5 to activate the signalling adaptor MAVS through interactions between the caspase recruitment domains (CARDs) of the two proteins. The molecular mechanism of MDA5 signalling is not well understood. Here, we show that MDA5 cooperatively binds short RNA ligands as a dimer with a 16–18-basepair footprint. A crystal structure of the MDA5 helicase-insert domain demonstrates an evolutionary relationship with the archaeal Hef helicases. In X-ray solution structures, the CARDs in unliganded MDA5 are flexible, and RNA binds on one side of an asymmetric MDA5 dimer, bridging the two subunits. On longer RNA, full-length and CARD-deleted MDA5 constructs assemble into ATP-sensitive filaments. We propose a signalling model in which the CARDs on MDA5–RNA filaments nucleate the assembly of MAVS filaments with the same polymeric geometry. PMID:22314235

  15. Influence of depleted uranium on hepatic cholesterol metabolism in apolipoprotein E-deficient mice.

    PubMed

    Souidi, M; Racine, R; Grandcolas, L; Grison, S; Stefani, J; Gourmelon, P; Lestaevel, P

    2012-04-01

    Depleted uranium (DU) is uranium with a lower content of the fissile isotope U-235 than natural uranium. It is a radioelement and a waste product from the enrichment process of natural uranium. Because of its very high density, it is used in the civil industry and for military purposes. DU exposure can affect many vital systems in the human body, because in addition to being weakly radioactive, uranium is a toxic metal. It should be emphasized that, to be exposed to radiation from DU, you have to eat, drink, or breathe it, or get it on your skin. This particular study is focusing on the health effects of DU for the cholesterol metabolism. Previous studies on the same issue have shown that the cholesterol metabolism was modulated at molecular level in the liver of laboratory rodents contaminated for nine months with DU. However, this modulation was not correlated with some effects at organs or body levels. It was therefore decided to use a "pathological model" such as hypercholesterolemic apolipoprotein E-deficient laboratory mice in order to try to clarify the situation. The purpose of the present study is to assess the effects of a chronic ingestion (during 3 months) of a low level DU-supplemented water (20 mg L(-1)) on the above mentioned mice in order to determine a possible contamination effect. Afterwards the cholesterol metabolism was studied in the liver especially focused on the gene expressions of cholesterol-catabolising enzymes (CYP7A1, CYP27A1 and CYP7B1), as well as those of associated nuclear receptors (LXRα, FXR, PPARα, and SREBP 2). In addition, mRNA levels of other enzymes of interest were measured (ACAT 2, as well as HMGCoA Reductase and HMGCoA Synthase). The gene expression study was completed with SRB1 and LDLr, apolipoproteins A1 and B and membrane transporters ABC A1, ABC G5. The major effect induced by a low level of DU contamination in apo-E deficient mice was a decrease in hepatic gene expression of the enzyme CYP7B1 (-23%) and nuclear

  16. Determination of Abraham model solute descriptors for the monomeric and dimeric forms of trans-cinnamic acid using measured solubilities from the Open Notebook Science Challenge.

    PubMed

    Bradley, Jean-Claude; Abraham, Michael H; Acree, William E; Lang, Andrew Sid; Beck, Samantha N; Bulger, David A; Clark, Elizabeth A; Condron, Lacey N; Costa, Stephanie T; Curtin, Evan M; Kurtu, Sozit B; Mangir, Mark I; McBride, Matthew J

    2015-01-01

    Calculating Abraham descriptors from solubility values requires that the solute have the same form when dissolved in all solvents. However, carboxylic acids can form dimers when dissolved in non-polar solvents. For such compounds Abraham descriptors can be calculated for both the monomeric and dimeric forms by treating the polar and non-polar systems separately. We illustrate the method of how this can be done by calculating the Abraham descriptors for both the monomeric and dimeric forms of trans-cinnamic acid, the first time that descriptors for a carboxylic acid dimer have been obtained. Abraham descriptors were calculated for the monomeric form of trans-cinnamic acid using experimental solubility measurements in polar solvents from the Open Notebook Science Challenge together with a number of water-solvent partition coefficients from the literature. Similarly, experimental solubility measurements in non-polar solvents were used to determine Abraham descriptors for the trans-cinnamic acid dimer. Abraham descriptors were calculated for both the monomeric and dimeric forms of trans-cinnamic acid. This allows for the prediction of further solubilities of trans-cinnamic acid in both polar and non-polar solvents with an error of about 0.10 log units. Graphical abstractMolar concentration of trans-cinnamic acid in various polar and non-polar solvents.

  17. Apolipoprotein E expression and behavioral toxicity of high charge, high energy (HZE) particle radiation

    NASA Technical Reports Server (NTRS)

    Higuchi, Yoshinori; Nelson, Gregory A.; Vazquez, Marcelo; Laskowitz, Daniel T.; Slater, James M.; Pearlstein, Robert D.

    2002-01-01

    Apolipoprotein E (apoE) is a lipid binding protein that plays an important role in tissue repair following brain injury. In the present studies, we have investigated whether apoE affects the behavioral toxicity of high charge, high energy (HZE) particle radiation. METHODS: Sixteen male apoE knockout (KO) mice and sixteen genetically matched wild-type (WT) C57BL mice were used in this experiment. Half of the KO and half of the WT animals were irradiated with 600 MeV/amu iron particles (2 Gy whole body). The effect of irradiation on motor coordination and stamina (Rotarod test), exploratory behavior (open field test), and spatial working and reference memory (Morris water maze) was assessed. ROTAROD TEST: Performance was adversely affected by radiation exposure in both KO and WT groups at 30 d after irradiation. By 60 d after radiation, the radiation effect was lost in WT, but still apparent in irradiated KO mice. OPEN FIELD TEST: Radiation reduced open field exploratory activity 14, 28, 56, 84, and 168 d after irradiation of KO mice, but had no effect on WT mice. MORRIS WATER MAZE: Radiation adversely affected spatial working memory in the KO mice, but had no discernible effect in the WT mice as assessed 180 d after irradiation. In contrast, irradiated WT mice showed marked impairment of spatial reference memory in comparison to non-irradiated mice, while no effect of radiation was observed in KO mice. CONCLUSIONS: These studies show that apoE expression influences the behavioral toxicity of HZE particle radiation and suggest that apoE plays a role in the repair/recovery from radiation injury of the CNS. ApoE deficiency may exacerbate the previously reported effects of HZE particle radiation in accelerating the brain aging process.

  18. Hyperlipidemia Impaired Innate Immune Response to Periodontal Pathogen Porphyromonas gingivalis in Apolipoprotein E Knockout Mice

    PubMed Central

    Yan, Fuhua; Xiao, Yin

    2013-01-01

    A finely-tuned innate immune response plays a pivotal role in protecting host against bacterial invasion during periodontal disease progression. Hyperlipidemia has been suggested to exacerbate periodontal health condition. However, the underlying mechanism has not been addressed. In the present study, we investigated the effect of hyperlipidemia on innate immune responses to periodontal pathogen Porphyromonas gingivalis infection. Apolipoprotein E-deficient and wild-type mice at the age of 20 weeks were used for the study. Peritoneal macrophages were isolated and subsequently used for the study of viable P. gingivalis infection. ApoE−/− mice demonstrated inhibited iNOS production and impaired clearance of P. gingivalis in vitro and in vivo; furthermore, ApoE−/− mice displayed disrupted cytokine production pattern in response to P. gingivalis, with a decreased production of tumor necrosis factor-α, interleukin-6 (IL-6), IL-1β and monocyte chemotactic protein-1. Microarray data demonstrated that Toll-like receptor (TLR) and NOD-like receptor (NLR) pathway were altered in ApoE−/− mice macrophages; further analysis of pattern recognition receptors (PRRs) demonstrated that expression of triggering receptors on myeloid cells-1 (TREM-1), an amplifier of the TLR and NLR pathway, was decreased in ApoE−/− mice macrophages, leading to decreased recruitment of NF-κB onto the promoters of the TNF-α and IL-6. Our data suggest that in ApoE−/− mice hyperlipidemia disrupts the expression of PRRs, and cripples the host’s capability to generate sufficient innate immune response to P. gingivalis, which may facilitate immune evasion, subgingival colonization and establishment of P. gingivalis in the periodontal niche. PMID:23977160

  19. Different associations of apolipoprotein E polymorphism with metabolic syndrome by sex in an elderly Chinese population.

    PubMed

    Tao, Meng Hua; Liu, Jian Wei; LaMonte, Michael J; Liu, Jing; Wang, Lei; He, Yao; Li, Xiao Ying; Wang, Lu Ning; Ye, Ling

    2011-10-01

    The metabolic syndrome (MetS) is characterized by a cluster of metabolic disorders including abnormal lipid and lipoprotein metabolism. Apolipoprotein E (ApoE) is involved in the regulation of the metabolism of cholesterol, lipoproteins, and triglycerides. The common ApoE polymorphism has been found to be associated with cardiovascular disease and diabetes. This study evaluated the ApoE genetic polymorphism and its relation to MetS defined by the modified National Cholesterol Education Program and International Diabetes Federation criteria in a population-based cross-sectional survey of an elderly Chinese population in Beijing, China. Genotypes of 937 men and 1385 women were included in the study. All participants were measured for blood pressure, anthropometric measurements, and fasting concentrations of glucose, triglycerides, cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol. We applied a logistic regression model to derive adjusted odds ratios (ORs) and their 95% confidence intervals. In this Chinese population, the ɛ2, ɛ3, and ɛ4 allele frequencies were 8.3%, 83.4%, and 8.3% for men and 8.7%, 82.9%, and 8.4% for women, respectively. In men, concentrations of fasting triglycerides were higher among the APOE2 and E4 subjects; and a lower level of high-density lipoprotein cholesterol was observed in the APOE4 group. There were approximately linear associations of low-density lipoprotein cholesterol levels with APOE genotype groups in both men and women. We observed that the ɛ4 allele was associated with a significantly increased OR of MetS defined by the modified National Cholesterol Education Program criteria in men (OR, 1.75; 95% confidence interval, 1.17-2.63). In summary, our data show that common polymorphism of ApoE gene is associated with the presence of MetS in an elderly Chinese population. Copyright © 2011 Elsevier Inc. All rights reserved.

  20. Cerebral amyloid angiopathy in a 95+ cohort: complement activation and apolipoprotein E (ApoE) genotype.

    PubMed

    Tanskanen, M; Lindsberg, P J; Tienari, P J; Polvikoski, T; Sulkava, R; Verkkoniemi, A; Rastas, S; Paetau, A; Kiuru-Enari, S

    2005-12-01

    There is growing evidence that in Alzheimer's disease (AD) amyloid beta-protein (Abeta) triggers a chronic inflammatory reaction in cerebral amyloid plaques, including complement proteins. Abeta also accumulates cerebrovascularly in age- and AD-associated cerebral amyloid angiopathy (CAA). We investigated complement proteins in CAA in a population-based series using histological and immunohistochemical staining methods. The 74 subjects, aged 95 years or more, had undergone clinical neurological examination and apolipoprotein E (ApoE) genotyping. The brains had been studied for AD post-mortem, allowing us to relate the histopathological findings to clinical and genetic conditions. CAA with congophilic amyloid was found in 36/74 individuals (48.6%). The vascular amyloid deposits immunoreacted with antibodies to Abeta and complements 3d (C3d) and 9 (C9). The positivity in complement stains increased with growing severity of CAA (P = 0.001). The presence of CAA associated with ApoE epsilon4 (P = 0.0005) and overrepresentation of epsilon4 among those with moderate or severe vs. mild CAA (P = 0.03) was demonstrated. The presence of CAA associated with dementia (P = 0.01), which was contributed by both epsilon4+ (P = 0.02) and epsilon4- (P = 0.06) subjects. Our study shows that complement proteins are deposited in the affected vessels in Abeta-associated CAA. They may solely represent the cerebral Abeta- burden associated to inflammatory stimuli, or signal a contribution in the clearance of cerebral Abeta, thereby contributing to the events associated with evolution of clinical dementia. Our results demonstrate a strong association between CAA and ApoE epsilon4 as well as dementia and suggest that the contribution of CAA to dementia is largely independent of ApoE epsilon4.

  1. Differential action of glucocorticoids on apolipoprotein E gene expression in macrophages and hepatocytes

    PubMed Central

    Trusca, Violeta Georgeta; Fuior, Elena Valeria; Fenyo, Ioana Madalina; Kardassis, Dimitris; Simionescu, Maya

    2017-01-01

    Apolipoprotein E (apoE) has anti-atherosclerotic properties, being involved in the transport and clearance of cholesterol-rich lipoproteins as well as in cholesterol efflux from cells. We hypothesized that glucocorticoids may exert anti-inflammatory properties by increasing the level of macrophage-derived apoE. Our data showed that glucocorticoids increased apoE expression in macrophages in vitro as well as in vivo. Dexamethasone increased ~6 fold apoE mRNA levels in cultured peritoneal macrophages and RAW 264.7 cells. Administered to C57BL/6J mice, dexamethasone induced a two-fold increase in apoE expression in peritoneal macrophages. By contrast, glucocorticoids did not influence apoE expression in hepatocytes, in vitro and in vivo. Moreover, dexamethasone enhanced apoE promoter transcriptional activity in RAW 264.7 macrophages, but not in HepG2 cells, as tested by transient transfections. Analysis of apoE proximal promoter deletion mutants, complemented by protein-DNA interaction assays demonstrated the functionality of a putative glucocorticoid receptors (GR) binding site predicted by in silico analysis in the -111/-104 region of the human apoE promoter. In hepatocytes, GR can bind to their specific site within apoE promoter but are not able to modulate the gene expression. The modulatory blockade in hepatocytes is a consequence of partial involvement of transcription factors and other signaling molecules activated through MEK1/2 and PLA2/PLC pathways. In conclusion, our study indicates that glucocorticoids (1) differentially target apoE gene expression; (2) induce a significant increase in apoE level specifically in macrophages. The local increase of apoE gene expression in macrophages at the level of the atheromatous plaque may have therapeutic implications in atherosclerosis. PMID:28355284

  2. Tau hyperphosphorylation in apolipoprotein E-deficient and control mice after closed head injury.

    PubMed

    Genis, L; Chen, Y; Shohami, E; Michaelson, D M

    2000-05-15

    Apolipoprotein E (apoE)-deficient mice have learning and memory impairments that are associated with specific neurochemical changes and hyperphosphorylation of distinct epitopes of the cytoskeletal protein tau. Furthermore, such mice are highly susceptible to the sequelae of brain trauma and their ability to recover from head injury is impaired. In the present study we investigated the extent that the neuronal maintenance and repair impairments of apoE-deficient mice are related to aberrations at the tau phosphorylation level. This was pursued by subjecting control and apoE-deficient mice to closed head injury (CHI) and examination, utilizing immunoblot assays, of the resulting effects on tau phosphorylation. The results thus obtained revealed that tau of apoE-deficient mice is hyperphosphorylated before CHI and that this insult results in transient tau hyperphosphorylation, whose extent and time course in the two mouse groups varied markedly. Tau hyperphosphorylation in the injured controls was maximal by about 4 hr after injury and reverted to basal levels by 24 hr. In contrast, almost no head injury-induced tau hyperphosphorylation was observed in the apoE-deficient mice at 4 hr after injury. Some tau hyper-phosphorylation was detected in the head-injured apoE-deficient mice after longer time intervals, but its extent was markedly lower than the maximal values obtained in the head injured controls. These findings show that the chronic neuronal impairments brought about by apoE deficiency and the acute response to head injury are both associated with hyperphosphorylation of the same tau domain and that the ability of apoE-deficient mice to mount the acute tau hyperphosphorylation response to head injury is impaired.

  3. Safrole-2',3'-oxide induces atherosclerotic plaque vulnerability in apolipoprotein E-knockout mice.

    PubMed

    Su, Le; Zhang, Haiyan; Zhao, Jing; Zhang, Shangli; Zhang, Yun; Zhao, Baoxiang; Miao, Junying

    2013-02-27

    Safrole-2',3'-oxide (SFO) is the major electrophilic metabolite of safrole (4-allyl-1, 2-methylenedioxybenzene), a natural plant constituent found in essential oils of numerous edible herbs and spices and in food containing these herbs, such as pesto sauce, cola beverages and bologna sausages. The effects of SFO in mammalian systems, especially the cardiovascular system, are little known. Disruption of vulnerable atherosclerotic plaques in atherosclerosis, a chronic inflammatory disease, is the main cause of cardiovascular events. In this study, we investigated SFO-induced atherosclerotic plaque vulnerability (possibility of rupture) in apolipoprotein E-knockout (apoE(-/-)) mice. Lipid area in vessel wall reached 59.8% in high dose SFO (SFO-HD) treated group, which is only 31.2% in control group. SFO treatment changed the lesion composition to an unstable phenotype, increased the number of apoptotic cells in plaque and the endothelium in plaques was damaged after SFO treatment. Furthermore, compared with control groups, the plaque endothelium level of p75(NTR) was 3-fold increased and the liver level of p75(NTR) was 17.4-fold increased by SFO-HD. Meanwhile, the serum level of KC (a functional homolog of IL-8 and the main proinflammatory alpha chemokine in mice) in apoE(-/-) mice was up to 357pg/ml in SFO-HD treated group. Thus, SFO contributes to the instability of atherosclerotic plaque in apoE(-/-) mice through activating p75(NTR) and IL-8 and cell apoptosis in plaque. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  4. Apolipoprotein E metabolism and functions in brain and its role in Alzheimer's disease

    PubMed Central

    Liao, Fan; Yoon, Hyejin; Kim, Jungsu

    2017-01-01

    Purpose of review APOE4 genotype is the strongest genetic risk factor for Alzheimer's disease. Prevailing evidence suggests that amyloid β plays a critical role in Alzheimer's disease. The objective of this article is to review the recent findings about the metabolism of apolipoprotein E (ApoE) and amyloid β and other possible mechanisms by which ApoE contributes to the pathogenesis of Alzheimer's disease. Recent findings ApoE isoforms have differential effects on amyloid β metabolism. Recent studies demonstrated that ApoE-interacting proteins, such as ATP-binding cassette A1 (ABCA1) and LDL receptor, may be promising therapeutic targets for Alzheimer's disease treatment. Activation of liver X receptor and retinoid X receptor pathway induces ABCA1 and other genes, leading to amyloid β clearance. Inhibition of the negative regulators of ABCA1, such as microRNA-33, also induces ABCA1 and decreases the levels of ApoE and amyloid β. In addition, genetic inactivation of an E3 ubiquitin ligase, myosin regulatory light chain interacting protein, increases LDL receptor levels and inhibits amyloid accumulation. Although amyloid β-dependent pathways have been extensively investigated, there have been several recent studies linking ApoE with vascular function, neuroinflammation, metabolism, synaptic plasticity, and transcriptional regulation. For example, ApoE was identified as a ligand for a microglial receptor, TREM2, and studies suggested that ApoE may affect the TREM2-mediated microglial phagocytosis. Summary Emerging data suggest that ApoE affects several amyloid β-independent pathways. These underexplored pathways may provide new insights into Alzheimer's disease pathogenesis. However, it will be important to determine to what extent each mechanism contributes to the pathogenesis of Alzheimer's disease. PMID:27922847

  5. Serum apolipoprotein E concentration and polymorphism influence serum lipid levels in Chinese Shandong Han population.

    PubMed

    Han, ShuYi; Xu, YiHui; Gao, MeiHua; Wang, YunShan; Wang, Jun; Liu, YanYan; Wang, Min; Zhang, XiaoQian

    2016-12-01

    Apolipoprotein E (ApoE), which has been shown to influence serum lipid parameters, can bind to multiple types of lipids and plays an important role in the metabolism and homeostasis of lipids and lipoproteins. A previous study showed that ApoE concentration significantly affects serum lipid levels independently of ApoE polymorphism. The serum lipid levels were also closely correlated with dietary habits, and Shandong cuisine is famous for its high salt and oil contents, which widely differ among the different areas in China. Therefore, studying the effect of ApoE polymorphism on ApoE concentration and serum lipid levels in Shandong province is very important.A total of 815 subjects including 285 men and 530 women were randomly selected and studied from Jinan, Shandong province. In order to evaluate the association of ApoE polymorphism and serum level on lipid profiles, the ApoE genotypes, as well as levels of fasting serum ApoE and other lipid parameters, were detected in all subjects.The frequency of the ApoE E3 allele was highest (83.1%), while those of E2 and E4 were 9.4% and 7.5%, respectively, which are similar to those in other Asian populations. ApoE2 allele carriers showed significantly increased ApoE levels but lower levels of serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and Apolipoprotein B (ApoB).We found that ApoE level is influenced by ApoE polymorphism in a gene-dependent manner. The ApoE polymorphism showed different influences on serum lipid parameters with increasing age and body mass index (BMI) in our Shandong Han population.

  6. Serum apolipoprotein E concentration and polymorphism influence serum lipid levels in Chinese Shandong Han population

    PubMed Central

    Han, ShuYi; Xu, YiHui; Gao, MeiHua; Wang, YunShan; Wang, Jun; Liu, YanYan; Wang, Min; Zhang, XiaoQian

    2016-01-01

    Abstract Apolipoprotein E (ApoE), which has been shown to influence serum lipid parameters, can bind to multiple types of lipids and plays an important role in the metabolism and homeostasis of lipids and lipoproteins. A previous study showed that ApoE concentration significantly affects serum lipid levels independently of ApoE polymorphism. The serum lipid levels were also closely correlated with dietary habits, and Shandong cuisine is famous for its high salt and oil contents, which widely differ among the different areas in China. Therefore, studying the effect of ApoE polymorphism on ApoE concentration and serum lipid levels in Shandong province is very important. A total of 815 subjects including 285 men and 530 women were randomly selected and studied from Jinan, Shandong province. In order to evaluate the association of ApoE polymorphism and serum level on lipid profiles, the ApoE genotypes, as well as levels of fasting serum ApoE and other lipid parameters, were detected in all subjects. The frequency of the ApoE E3 allele was highest (83.1%), while those of E2 and E4 were 9.4% and 7.5%, respectively, which are similar to those in other Asian populations. ApoE2 allele carriers showed significantly increased ApoE levels but lower levels of serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and Apolipoprotein B (ApoB). We found that ApoE level is influenced by ApoE polymorphism in a gene-dependent manner. The ApoE polymorphism showed different influences on serum lipid parameters with increasing age and body mass index (BMI) in our Shandong Han population. PMID:27977609

  7. Apolipoprotein E epsilon4 allele differentiates the clinical response to donepezil in Alzheimer's disease.

    PubMed

    Bizzarro, A; Marra, C; Acciarri, A; Valenza, A; Tiziano, F D; Brahe, C; Masullo, C

    2005-01-01

    The existence of an association between apolipoprotein E (APOE) and Alzheimer's disease (AD) has been reported in several studies. The possession of an ApoE epsilon4 allele is now considered a genetic risk factor for sporadic AD. There has been a growing agreement about the role exerted by the ApoE epsilon4 allele on the neuropsychological profile and the rate of cognitive decline in AD patients. However, a more controversial issue remains about a possible influence of the APOE genotype on acetylcholinesterase inhibitor therapy response in AD patients. In order to address this issue, 81 patients diagnosed as having probable AD were evaluated by a complete neuropsychological test battery at the time of diagnosis (baseline) and after 12-16 months (retest). Patients were divided into two subgroups: (1) treated with donepezil at a dose of 5 mg once a day (n = 41) and (2) untreated (n = 40). Donepezil therapy was started after baseline evaluation. The APOE genotype was determined according to standardized procedures. We evaluated the possible effect of the APOE genotype on the neuropsychological tasks in relation to donepezil therapy. The statistical analysis of the results showed a global worsening of cognitive performances for all AD patients at the retest. Differences in the clinical outcome were analysed in the four subgroups of AD patients for each neuropsychological task. ApoE epsilon4 carriers/treated patients had improved or unchanged scores at retest evaluation for the following tasks: visual and verbal memory, visual attention and inductive reasoning and Mini Mental State Examination. These results indicate an effect of donepezil on specific cognitive domains (attention and memory) in the ApoE epsilon4 carriers with AD. This might suggest an early identification of AD patients carrying at least one epsilon4 allele as responders to donepezil therapy.

  8. Apolipoprotein E gene polymorphism and Alzheimer's disease in Chinese population: a meta-analysis

    NASA Astrophysics Data System (ADS)

    Liu, Mengying; Bian, Chen; Zhang, Jiqiang; Wen, Feng

    2014-03-01

    The relationship between Apolipoprotein E (ApoE) genotype and the risk of Alzheimer's disease (AD) is relatively well established in Caucasians, but less established in other ethnicities. To examine the association between ApoE polymorphism and the onset of AD in Chinese population, we searched the commonly used electronic databases between January 2000 and November 2013 for relevant studies. Total 20 studies, including 1576 cases and 1741 controls, were retrieved. The results showed statistically significant positive association between risk factor ɛ4 allele carriers and AD in Chinese population (OR = 3.93, 95% CI = 3.37-4.58, P < 0.00001). Genotype ApoE ɛ4/ɛ4 and ɛ4/ɛ3 have statistically significant association with AD as well (ɛ4/ɛ4: OR = 11.76, 95% CI = 6.38-21.47, P < 0.00001; ɛ4/ɛ3: OR = 3.08, 95% CI = 2.57-3.69, P < 0.00001). Furthermore, the frequency of the ApoE ɛ3 is lower in AD than that in the health controls, and the difference of ɛ3 allele is also statistically significant (OR = 0.42, 95% CI = 0.37-0.47, P < 0.00001). No significant heterogeneity was observed among all studies. This meta-analysis suggests that the subject with at least one ApoE ɛ4 allele has higher risk suffering from AD than controls in Chinese population. The results also provide a support for the protection effect of ApoE ɛ3 allele in developing AD.

  9. Apolipoprotein E genetic polymorphism, serum lipoprotein levels and breast cancer risk: A case-control study

    PubMed Central

    CIBEIRA, GABRIELA HERRMANN; GIACOMAZZI, JULIANA; AGUIAR, ERNESTINA; SCHNEIDER, SILVANA; ETTRICH, BETINA; DE SOUZA, CAROLINE ISOPPO; CAMEY, SUZI; CALEFFI, MAIRA; WEBER, BERNARDETE; ASHTON-PROLLA, PATRICIA; MORIGUCHI, EMILIO HIDEYUKI

    2014-01-01

    The purpose of this study was to evaluate the association between apolipoprotein E (APOE) allelic frequency, serum lipoproteins and breast cancer (BC). We conducted a nested case-control study within a cohort including 47 cases and 165 controls. Polymerase chain reaction-restriction fragment length polymorphism analyses of the APOE polymorphism were performed. In general, participants with the genotype including alleles e2 and e3 tended to have lower serum triglycerides, total cholesterol and low-density lipoprotein cholesterol levels and higher high-density lipoprotein (HDL) cholesterol levels compared to participants homozygous for the e3 allele and participants heterozygous for the e3 and e4 alleles, respectively. BC patients exhibited higher mean levels of total serum cholesterol (P=0.070), dietary fat intake (P=0.020) and dietary cholesterol intake (P=0.017) compared to control subjects. The allelic distribution between the two groups revealed that the presence of the e2 allele was positively associated with the absence of BC, whereas the e4 allele was positively associated with the BC case group (P=0.019). The distribution of the APOE genotypes was not significantly different between cases and controls (P=0.172). The concomitant presence of the e2 and e4 alleles was positively associated with the absence of BC and e4/e4 homozygosity was positively associated with BC (P=0.021). Our findings suggested that APOE polymorphism plays an important role in the development of BC, particularly when associated with higher serum triglyceride levels. PMID:25279190

  10. Apolipoprotein E and Alzheimer disease: genotype-specific risks by age and sex.

    PubMed Central

    Bickeböller, H; Campion, D; Brice, A; Amouyel, P; Hannequin, D; Didierjean, O; Penet, C; Martin, C; Pérez-Tur, J; Michon, A; Dubois, B; Ledoze, F; Thomas-Anterion, C; Pasquier, F; Puel, M; Demonet, J F; Moreaud, O; Babron, M C; Meulien, D; Guez, D; Chartier-Harlin, M C; Frebourg, T; Agid, Y; Martinez, M; Clerget-Darpoux, F

    1997-01-01

    The distribution of apolipoprotein E (APOE) genotypes as a function of age and sex has been examined in a French population of 417 Alzheimer disease (AD) patients and 1,030 control subjects. When compared to the APOE epsilon3 allele, an increased risk associated with the APOE epsilon4 allele (odds ratio [OR] [epsilon4] = 2.7 with 95% confidence interval [CI] = 2.0-3.6; P < .001) and a protective effect of the APOE epsilon2 allele (OR[epsilon2] = 0.5 with 95% CI = 0.3-0.98; P = .012) were retrieved. An effect of the epsilon4 allele dosage on susceptibility was confirmed (OR[epsilon4/epsilon4] vs. the epsilon3/epsilon3 genotype = 11.2 [95% CI = 4.0-31.6]; OR[epsilon3/epsilon4] vs. the epsilon3/epsilon3 genotype = 2.2 [95% CI = 1.5-3.5]). The frequency of the epsilon4 allele was lower in male cases than in female cases, but, since a similar difference was found in controls, this does not lead to a difference in OR between sex. ORs for the epsilon4 allele versus the epsilon3 allele, OR(epsilon4), were not equal in all age classes: OR(epsilon4) in the extreme groups with onset at < 60 years or > 79 years were significantly lower than those from the age groups 60-79 years. In epsilon3/epsilon4 individuals, sex-specific lifetime risk estimates by age 85 years (i.e., sex-specific penetrances by age 85 years) were 0.14 (95% CI 0.04-0.30) for men and 0.17 (95% CI 0.09-0.28) for women. PMID:9012418

  11. A FDG-PET Study of Metabolic Networks in Apolipoprotein E ε4 Allele Carriers.

    PubMed

    Yao, Zhijun; Hu, Bin; Zheng, Jiaxiang; Zheng, Weihao; Chen, Xuejiao; Gao, Xiang; Xie, Yuanwei; Fang, Lei

    2015-01-01

    Recently, some studies have applied the graph theory in brain network analysis in Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI). However, relatively little research has specifically explored the properties of the metabolic network in apolipoprotein E (APOE) ε4 allele carriers. In our study, all the subjects, including ADs, MCIs and NCs (normal controls) were divided into 165 APOE ε4 carriers and 165 APOE ε4 noncarriers. To establish the metabolic network for all brain regions except the cerebellum, cerebral glucose metabolism data obtained from FDG-PET (18F-fluorodeoxyglucose positron emission tomography) were segmented into 90 areas with automated anatomical labeling (AAL) template. Then, the properties of the networks were computed to explore the between-group differences. Our results suggested that both APOE ε4 carriers and noncarriers showed the small-world properties. Besides, compared with APOE ε4 noncarriers, the carriers showed a lower clustering coefficient. In addition, significant changes in 6 hub brain regions were found in between-group nodal centrality. Namely, compared with APOE ε4 noncarriers, significant decreases of the nodal centrality were found in left insula, right insula, right anterior cingulate, right paracingulate gyri, left cuneus, as well as significant increases in left paracentral lobule and left heschl gyrus in APOE ε4 carriers. Increased local short distance interregional correlations and disrupted long distance interregional correlations were found, which may support the point that the APOE ε4 carriers were more similar with AD or MCI in FDG uptake. In summary, the organization of metabolic network in APOE ε4 carriers indicated a less optimal pattern and APOE ε4 might be a risk factor for AD.

  12. Inhibition of Interleukin-10 Signaling Induces Microbiota-Dependent Chronic Colitis in Apolipoprotein E Deficient Mice

    PubMed Central

    Singh, Vishal; Kumar, Manish; Yeoh, Beng San; Xiao, Xia; Saha, Piu; Kennett, Mary J.; Vijay-Kumar, Matam

    2015-01-01

    Background Apolipoprotein E (ApoE) mediates potent anti-inflammatory and immunomodulatory properties in addition to its roles in regulating cholesterol transport and metabolism. However, its role in the intestine, specifically during inflammation is largely unknown. Methods Mice [C57BL/6 or ApoE deficient (ApoE-KO) mice] were administered either single or four injections (weekly) of anti-interleukin (IL)-10 receptor monoclonal antibody (1.0 mg/mouse; intraperitoneally) and euthanized one week after the last injection. 16S rRNA sequencing was performed in fecal samples to analyze the gut bacterial load and its composition. Microbiota was ablated by administration of broad-spectrum antibiotics in drinking water. IL-10KO mice were cohoused with ApoE-KO mice or their WT littermates to monitor the colitogenic potential of gut microbiota harbored in ApoE-KO mice. Results ApoE-KO mice developed severe colitis upon neutralization of IL-10 signaling as assessed by every parameter analyzed. 16S rRNA sequencing revealed that the ApoE-KO mice display elevated and altered gut microbiota that were accompanied with impaired production of intestinal antimicrobial peptides. Interestingly, microbiota ablation ameliorates the colitis development in ApoE-KO mice. Exacerbated and accelerated colitis was observed in IL-10KO mice when cohoused with ApoE-KO mice. Conclusions Our study highlights a novel interplay between ApoE and IL-10 in maintaining gut homeostasis and that such cross-talk may play a critical role in inflammatory bowel disease (IBD) pathogenesis. Gut sterilization and cohousing experiment suggests that microbiota play pivotal role in the development of IBD in mice lacking ApoE. PMID:26891260

  13. Cognitive deficits and disruption of neurogenesis in a mouse model of apolipoprotein E4 domain interaction.

    PubMed

    Adeosun, Samuel O; Hou, Xu; Zheng, Baoying; Stockmeier, Craig; Ou, Xiaoming; Paul, Ian; Mosley, Thomas; Weisgraber, Karl; Wang, Jun Ming

    2014-01-31

    Apolipoprotein E4 (apoE4) allele is the major genetic risk factor for sporadic Alzheimer disease (AD) due to the higher prevalence and earlier onset of AD in apoE4 carriers. Accumulating data suggest that the interaction between the N- and the C-terminal domains in the protein may be the main pathologic feature of apoE4. To test this hypothesis, we used Arg-61 mice, a model of apoE4 domain interaction, by introducing the domain interaction feature of human apoE4 into native mouse apoE. We carried out hippocampus-dependent learning and memory tests and related cellular and molecular assays on 12- and 3-month-old Arg-61 and age-matched background C57BL/6J mice. Learning and memory task performance were impaired in Arg-61 mice at both old and young ages compared with C57BL/6J mice. Surprisingly, young Arg-61 mice had more mitotic doublecortin-positive cells in the subgranular zone; mRNA levels of brain-derived neurotrophic factor (BDNF) and TrkB were also higher in 3-month-old Arg-61 hippocampus compared with C57BL/6J mice. These early-age neurotrophic and neurogenic (proliferative) effects in the Arg-61 mouse may be an inadequate compensatory but eventually detrimental attempt by the system to "repair" itself. This is supported by the higher cleaved caspase-3 levels in the young animals that not only persisted, but increased in old age, and the lower levels of doublecortin at old age in the hippocampus of Arg-61 mice. These results are consistent with human apoE4-dependent cognitive and neuro-pathologic changes, supporting the principal role of domain interaction in the pathologic effect of apoE4. Domain interaction is, therefore, a viable therapeutic/prophylactic target for cognitive impairment and AD in apoE4 subjects.

  14. Induction of fibroblast apolipoprotein E expression during apoptosis, starvation-induced growth arrest and mitosis.

    PubMed Central

    Quinn, Carmel M; Kågedal, Katarina; Terman, Alexei; Stroikin, Uri; Brunk, Ulf T; Jessup, Wendy; Garner, Brett

    2004-01-01

    Apolipoprotein E (apoE) mediates the hepatic clearance of plasma lipoproteins, facilitates cholesterol efflux from macrophages and aids neuronal lipid transport. ApoE is expressed at high levels in hepatocytes, macrophages and astrocytes. In the present study, we identify nuclear and cytosolic pools of apoE in human fibroblasts. Fibroblast apoE mRNA and protein levels were up-regulated during staurosporine-induced apoptosis and this was correlated with increased caspase-3 activity and apoptotic morphological alterations. Because the transcription of apoE and specific pro-apoptotic genes is regulated by the nuclear receptor LXR (liver X receptor) alpha, we analysed LXRalpha mRNA expression by quantitative real-time PCR and found it to be increased before apoE mRNA induction. The expression of ABCA1 (ATP-binding cassette transporter A1) mRNA, which is also regulated by LXRalpha, was increased in parallel with apoE mRNA, indicating that LXRalpha probably promotes apoE and ABCA1 transcription during apoptosis. Fibroblast apoE levels were increased under conditions of serum-starvation-induced growth arrest and hyperoxia-induced senescence. In both cases, an increased nuclear apoE level was observed, particularly in cells that accumulated lipofuscin. Nuclear apoE was translocated to the cytosol when mitotic nuclear disassembly occurred and this was associated with an increase in total cellular apoE levels. ApoE amino acid sequence analysis indicated several potential sites for phosphorylation. In vivo studies, using 32P-labelling and immunoprecipitation, revealed that fibroblast apoE can be phosphorylated. These studies reveal novel associations and potential roles for apoE in fundamental cellular processes. PMID:14656220

  15. In Vivo Human Apolipoprotein E Isoform Fractional Turnover Rates in the CNS

    PubMed Central

    Patterson, Bruce W.; Pyatkivskyy, Yuriy; Kim, Jungsu; Yarasheski, Kevin E.; Wang, Jennifer X.; Mawuenyega, Kwasi G.; Jiang, Hong; Parsadanian, Maia; Yoon, Hyejin; Kasten, Tom; Sigurdson, Wendy C.; Xiong, Chengjie; Goate, Alison; Holtzman, David M.; Bateman, Randall J.

    2012-01-01

    Apolipoprotein E (ApoE) is the strongest genetic risk factor for Alzheimer’s disease and has been implicated in the risk for other neurological disorders. The three common ApoE isoforms (ApoE2, E3, and E4) each differ by a single amino acid, with ApoE4 increasing and ApoE2 decreasing the risk of Alzheimer’s disease (AD). Both the isoform and amount of ApoE in the brain modulate AD pathology by altering the extent of amyloid beta (Aβ) peptide deposition. Therefore, quantifying ApoE isoform production and clearance rates may advance our understanding of the role of ApoE in health and disease. To measure the kinetics of ApoE in the central nervous system (CNS), we applied in vivo stable isotope labeling to quantify the fractional turnover rates of ApoE isoforms in 18 cognitively-normal adults and in ApoE3 and ApoE4 targeted-replacement mice. No isoform-specific differences in CNS ApoE3 and ApoE4 turnover rates were observed when measured in human CSF or mouse brain. However, CNS and peripheral ApoE isoform turnover rates differed substantially, which is consistent with previous reports and suggests that the pathways responsible for ApoE metabolism are different in the CNS and the periphery. We also demonstrate a slower turnover rate for CSF ApoE than that for amyloid beta, another molecule critically important in AD pathogenesis. PMID:22675504

  16. Apolipoprotein E and measured physical and pulmonary function in older Taiwanese adults.

    PubMed

    Vasunilashorn, Sarinnapha; Glei, Dana A; Lin, Yu-Hsuan; Goldman, Noreen

    2013-01-01

    The apolipoprotein E (ApoE) gene, which has three common alleles (ϵ2, ϵ3, and ϵ4), has been linked to a number of health outcomes and longevity. The ϵ2 allele has been reported to have neuroprotective effects, whereas the ϵ4 allele has been shown to be a risk factor for cardiovascular disease and Alzheimer's disease in various populations. The relationships between ApoE and mortality and ApoE and physical function, however, are not clear-cut. We used the Social Environment and Biomarkers of Aging Study (SEBAS) to examine the relationship between ApoE polymorphisms and physical and pulmonary function in approximately 1,000 Taiwanese adults aged 53 years and older in 2006. In the 2006 SEBAS wave, measures of physical function included self-reported difficulties with respect to activities of daily living (ADLs) and other physical function indicators, as well as performance-based measures of grip strength (kg), walking speed (m/s) over a distance of 3 m, and chair stand speed (stand/s). Peak expiratory flow (PEF; L/min) rate was also examined as an indicator of pulmonary function. We used logistic regression models to determine the association between ApoE and inability to complete each of the tests of physical and pulmonary function. These models revealed no significant association between ApoE carrier status and any of the indicators of function. Among participants able to complete a given task, we next used linear regression models to examine self-reported limitations with ADLs and performance on the given test by ApoE carrier status. Similarly, there were no significant relationships between ApoE carrier status and the measures of function. Our estimates provide further confirmation that the ApoE gene may not be a risk factor for functional decline among older Taiwanese adults.

  17. Modulation of autoimmune arthritis severity in mice by apolipoprotein E (ApoE) and cholesterol.

    PubMed

    Alvarez, P; Genre, F; Iglesias, M; Augustin, J J; Tamayo, E; Escolà-Gil, J C; Lavín, B; Blanco-Vaca, F; Merino, R; Merino, J

    2016-12-01

    Apolipoprotein E (ApoE) deficiency promoted an exacerbation of autoimmune arthritis in mice by inducing proinflammatory immune responses. In this study we analysed the contribution of hypercholesterolaemia and/or the absence of ApoE anti-inflammatory properties, unrelated to its function in the control of cholesterol metabolism, towards the acceleration of arthritis in these mutant animals. The induction and severity of collagen type II-induced arthritis (CIA) were compared for B10.RIII wild-type (WT), B10.RIII.ApoE(+/-) , B10.RIII.ApoE(-/-) and B10.RIII.low-density lipoprotein receptor (LDLR(-/-) ) mice with different concentrations of circulating ApoE and cholesterol. A 50-70% reduction in serum levels of ApoE was observed in heterozygous B10.RIII.ApoE(+/-) mice in comparison to B10.RIII.WT, although both strains of mice exhibited similar circulating lipid profiles. This ApoE reduction was associated with an increased CIA severity that remained lower than in homozygous B10.RIII.ApoE(-/-) mice. An important rise in circulating ApoE concentration was observed in hypercholesterolaemic B10.RIII.LDLR(-/-) mice fed with a normal chow diet, and both parameters increased further with an atherogenic hypercholesterolaemic diet. However, the severity of CIA in B10.RIII.LDLR(-/-) mice was similar to that of B10.RIII.WT controls. In conclusion, by comparing the evolution of CIA between several strains of mutant mice with different levels of serum ApoE and cholesterol, our results demonstrate that both hypercholesterolaemia and ApoE regulate the intensity of in-vivo systemic autoimmune responses. © 2016 British Society for Immunology.

  18. Apolipoprotein E4 Elicits Lysosomal Cathepsin D Release, Decreased Thioredoxin-1 Levels, and Apoptosis

    PubMed Central

    Persson, Torbjörn; Lattanzio, Francesca; Calvo-Garrido, Javier; Rimondini, Roberto; Rubio-Rodrigo, Marta; Sundström, Erik; Maioli, Silvia; Sandebring-Matton, Anna; Cedazo-Mínguez, Ángel

    2016-01-01

    The major genetic risk factor for Alzheimer’s disease (AD), apolipoprotein E4 (ApoE4), has been suggested to have detrimental effects on neurons, including direct toxicity via apoptosis. Thioredoxin-1 (Trx1) is an endogenous antioxidant protein important for redox regulation and participates in the regulation of apoptosis through the inhibition of apoptosis signal-regulating kinase-1 (Ask-1). In this study, we have investigated the effects of ApoE on Trx1 in the brain. Our results showed that the protein levels of Trx1 were reduced in the hippocampus of ApoE4 targeted replacement (TR) mice compared to ApoE3 TR mice. The reduction was also seen in vitro after treatment of both human primary cortical neurons and neuroblastoma cells with human recombinant ApoE4 (rApoE4). Furthermore, ApoE4 caused a disruption of lysosomal integrity and a shift in the localization of Cathepsin D, an enzyme known to degrade Trx1. ApoE4 treatment induced in addition apoptosis through translocation of Death-domain associated protein-6 (Daxx) from the nucleus to the cytosol, suggesting an activation of the Ask-1 pathway. This toxicity was prevented by overexpression of Trx1 and other endogenous Ask-1 inhibitors. Our data suggests that down-regulation of Trx1 is involved in the toxicity caused by ApoE4. An activated ASK-1 pathway might indeed make cells more vulnerable to other insults such as amyloid-β, which could partially explain the mechanism behind the strongest genetic risk factor for AD. PMID:28035917

  19. Postmenopausal cognitive changes and androgen levels in the context of apolipoprotein E polymorphism

    PubMed Central

    Pinkas, Jarosław; Gujski, Mariusz; Owoc, Alfred; Raczkiewicz, Dorota; Gustaw-Rothenberg, Kasia

    2016-01-01

    Introduction The focus of this study was to assess cognitive functions in relation to androgens and specifically testosterone and dehydroepiandrosterone in postmenopausal women as well as the correlation between cognitive functions and these two androgens according to polymorphism of the apolipoprotein E gene (APOE). Material and methods A group of 402 women was recruited to the study (minimum 2 years after the last menstruation, follicle-stimulating hormone (FSH) more than 30 U/ml and no dementia signs on Montreal Cognitive Assessment). The computerized battery of the Central Nervous System Vital Signs test was used to diagnose cognitive functions. APOE genotyping was performed by multiplex polymerase chain reaction (PCR). Testosterone (TTE) and dehydroepiandrosterone (DHEA) in the blood serum were assessed for further statistical correlations analysis. Results In the group of postmenopausal women, higher testosterone concentration was associated with lower scores for Neurocognition Index (NCI) (p = 0.028), memory (p = 0.008) and psychomotor speed (p < 0.001). Presence of at least one APOE ε4 allele potentiated testosterone’s negative influence on cognitive functions (p < 0.05). Woman with a high normal level of DHEA scored significantly better in verbal (p = 0.027) and visual memory (p < 0.001) than other participants. APOE polymorphism did not modify the relationship between DHEA concentration and scores for cognitive functions. Conclusions Hormonal balance variations after menopause may influence brain processes concerned with cognition, especially memory and psychomotor speed. The observed effects may be related to androgens’ influence on higher cortical functions in the changed hormonal dynamics of the postmenopausal period. PMID:28883857

  20. Plasma levels of apolipoprotein-E in residents of the European North of Russia.

    PubMed

    Kaneva, Anastasiya M; Bojko, Evgeny R; Potolitsyna, Natalya N; Odland, Jon O

    2013-03-27

    Apolipoprotein-E (apoE) is one of the metabolically active apoproteins and plays an important role in lipid metabolism. However, there are no data on levels of apoE in residents of the North in spite of the fact that specific features of lipid metabolism in the northerners are described. The present work was designed to study plasma levels of apoE in residents of the European North of Russia. A total of 937 native residents of the European North of Russia (463 men and 474 women) aged 13-60 years were included in the study. ApoE concentrations in the blood plasma were measured by immunoturbidimetric method. Plasma levels of apoE in residents of the European North of Russia were low. ApoE concentrations below the defined normal values were detected in 57.0% of the men and in 59.2% of the women. The mean plasma levels of apoE did not significantly differ in men and women (2.80 mg/dl vs 2.87 mg/dl). Plasma apoE concentrations in residents of the European North of Russia changed with age. Plasma levels of apoE decreased from 13 to 21 years in men and from 13 to 35 years in women and then increased in both sexes (p < 0.001). The limits of variation of plasma apoE levels in residents of the European North of Russia shift towards lower values. Plasma levels of apoE below normal values were observed in approximately half of investigation subjects.

  1. Xyloketal B Attenuates Atherosclerotic Plaque Formation and Endothelial Dysfunction in Apolipoprotein E Deficient Mice

    PubMed Central

    Zhao, Li-Yan; Li, Jie; Yuan, Feng; Li, Mei; Zhang, Quan; Huang, Yun-Ying; Pang, Ji-Yan; Zhang, Bin; Sun, Fang-Yun; Sun, Hong-Shuo; Li, Qian; Cao, Lu; Xie, Yu; Lin, Yong-Cheng; Liu, Jie; Tan, Hong-Mei; Wang, Guan-Lei

    2015-01-01

    Our previous studies demonstrated that xyloketal B, a novel marine compound with a unique chemical structure, has strong antioxidant actions and can protect against endothelial injury in different cell types cultured in vitro and model organisms in vivo. The oxidative endothelial dysfunction and decrease in nitric oxide (NO) bioavailability are critical for the development of atherosclerotic lesion. We thus examined whether xyloketal B had an influence on the atherosclerotic plaque area in apolipoprotein E-deficient (apoE−/−) mice fed a high-fat diet and investigated the underlying mechanisms. We found in our present study that the administration of xyloketal B dose-dependently decreased the atherosclerotic plaque area both in the aortic sinus and throughout the aorta in apoE−/− mice fed a high-fat diet. In addition, xyloketal B markedly reduced the levels of vascular oxidative stress, as well as improving the impaired endothelium integrity and NO-dependent aortic vasorelaxation in atherosclerotic mice. Moreover, xyloketal B significantly changed the phosphorylation levels of endothelial nitric oxide synthase (eNOS) and Akt without altering the expression of total eNOS and Akt in cultured human umbilical vein endothelial cells (HUVECs). Here, it increased eNOS phosphorylation at the positive regulatory site of Ser-1177, while inhibiting phosphorylation at the negative regulatory site of Thr-495. Taken together, these findings indicate that xyloketal B has dramatic anti-atherosclerotic effects in vivo, which is partly due to its antioxidant features and/or improvement of endothelial function. PMID:25874925

  2. Nitric oxide-releasing agent, LA419, reduces atherogenesis in apolipoprotein E-deficient mice.

    PubMed

    Carnicer, Ricardo; Guillén, Natalia; Arbonés-Mainar, José M; Navarro, María A; Guzmán, Mario A; Barranquero, Cristina; Arnal, Carmen; Gascón, Sonia; Acín, Sergio; Mourelle, Marisabel; Osada, Jesús

    2009-05-01

    LA419 is a novel nitric oxide-donor with antioxidant properties. The effect of this compound on the development of atherosclerosis was investigated in apolipoprotein E-deficient mice. Male mice were randomized to receive vehicle or 5 mg/kg/day LA419 for 12 weeks. At the end of this period, plasma lipid and lipoprotein parameters, oxidative stress markers and hepatic fat, and mRNA levels were measured as well as en face and cross-sectional lesion areas of the aorta. Data showed that LA419 administration reduced atherosclerotic foci and cross-sectional lesion areas by decreasing the intimae presence of macrophage-derived foam cells despite an increase in plasma cholesterol. This agent induced a significant reduction in body weight gain and mass of adipose tissue. Furthermore, compared with placebo, LA419 administration significantly reduced plasma triglycerides and apolipoprotein C-III levels as well as systemic oxidative stress, estimated by plasma 8-isoprostane. Conversely, nonesterified fatty acid and HDL cholesterol levels remained unchanged, as well as apolipoproteins A-I, A-IV, and B and paraoxonase activity. Plasma triglycerides were significantly associated with plasma levels of apolipoprotein C-III and hepatic Fsp27 mRNA expression. These results indicate that administration of LA419 modulates lesion development. These actions are partly independent of total cholesterol as well as HDL particles and related to triglyceridemia and oxidative stress. Hypotriglyceridemia is associated with an equal number of apoB-containing particles. Hence, LA419 administration could be used as a safe alternative to control the metabolic syndrome and atherosclerosis.

  3. Low density lipoprotein receptor-related protein 1 dependent endosomal trapping and recycling of apolipoprotein E.

    PubMed

    Laatsch, Alexander; Panteli, Malamatenia; Sornsakrin, Marijke; Hoffzimmer, Britta; Grewal, Thomas; Heeren, Joerg

    2012-01-01

    Lipoprotein receptors from the low density lipoprotein (LDL) receptor family are multifunctional membrane proteins which can efficiently mediate endocytosis and thereby facilitate lipoprotein clearance from the plasma. The biggest member of this family, the LDL receptor-related protein 1 (LRP1), facilitates the hepatic uptake of triglyceride-rich lipoproteins (TRL) via interaction with apolipoprotein E (apoE). In contrast to the classical LDL degradation pathway, TRL disintegrate in peripheral endosomes, and core lipids and apoB are targeted along the endocytic pathway for lysosomal degradation. Notably, TRL-derived apoE remains within recycling endosomes and is then mobilized by high density lipoproteins (HDL) for re-secretion. The aim of this study is to investigate the involvement of LRP1 in the regulation of apoE recycling. Immunofluorescence studies indicate the LRP1-dependent trapping of apoE in EEA1-positive endosomes in human hepatoma cells. This processing is distinct from other LRP1 ligands such as RAP which is efficiently targeted to lysosomal compartments. Upon stimulation of HDL-induced recycling, apoE is released from LRP1-positive endosomes but is targeted to another, distinct population of early endosomes that contain HDL, but not LRP1. For subsequent analysis of the recycling capacity, we expressed the full-length human LRP1 and used an RNA interference approach to manipulate the expression levels of LRP1. In support of LRP1 determining the intracellular fate of apoE, overexpression of LRP1 significantly stimulated HDL-induced apoE recycling. Vice versa LRP1 knockdown in HEK293 cells and primary hepatocytes strongly reduced the efficiency of HDL to stimulate apoE secretion. We conclude that LRP1 enables apoE to accumulate in an early endosomal recycling compartment that serves as a pool for the intracellular formation and subsequent re-secretion of apoE-enriched HDL particles.

  4. Low Density Lipoprotein Receptor-Related Protein 1 Dependent Endosomal Trapping and Recycling of Apolipoprotein E

    PubMed Central

    Laatsch, Alexander; Panteli, Malamatenia; Sornsakrin, Marijke; Hoffzimmer, Britta; Grewal, Thomas; Heeren, Joerg

    2012-01-01

    Background Lipoprotein receptors from the low density lipoprotein (LDL) receptor family are multifunctional membrane proteins which can efficiently mediate endocytosis and thereby facilitate lipoprotein clearance from the plasma. The biggest member of this family, the LDL receptor-related protein 1 (LRP1), facilitates the hepatic uptake of triglyceride-rich lipoproteins (TRL) via interaction with apolipoprotein E (apoE). In contrast to the classical LDL degradation pathway, TRL disintegrate in peripheral endosomes, and core lipids and apoB are targeted along the endocytic pathway for lysosomal degradation. Notably, TRL-derived apoE remains within recycling endosomes and is then mobilized by high density lipoproteins (HDL) for re-secretion. The aim of this study is to investigate the involvement of LRP1 in the regulation of apoE recycling. Principal Findings Immunofluorescence studies indicate the LRP1-dependent trapping of apoE in EEA1-positive endosomes in human hepatoma cells. This processing is distinct from other LRP1 ligands such as RAP which is efficiently targeted to lysosomal compartments. Upon stimulation of HDL-induced recycling, apoE is released from LRP1-positive endosomes but is targeted to another, distinct population of early endosomes that contain HDL, but not LRP1. For subsequent analysis of the recycling capacity, we expressed the full-length human LRP1 and used an RNA interference approach to manipulate the expression levels of LRP1. In support of LRP1 determining the intracellular fate of apoE, overexpression of LRP1 significantly stimulated HDL-induced apoE recycling. Vice versa LRP1 knockdown in HEK293 cells and primary hepatocytes strongly reduced the efficiency of HDL to stimulate apoE secretion. Conclusion We conclude that LRP1 enables apoE to accumulate in an early endosomal recycling compartment that serves as a pool for the intracellular formation and subsequent re-secretion of apoE-enriched HDL particles. PMID:22238606

  5. Blue-Green Algae Inhibit the Development of Atherosclerotic Lesions in Apolipoprotein E Knockout Mice

    PubMed Central

    Ku, Chai Siah; Kim, Bohkyung; Pham, Tho X.; Yang, Yue; Wegner, Casey J.; Park, Young-Ki; Balunas, Marcy

    2015-01-01

    Abstract Hyperlipidemia and inflammation contribute to the development of atherosclerotic lesions. Our objective was to determine antiatherogenic effect of edible blue-green algae (BGA) species, that is, Nostoc commune var. sphaeroides Kützing (NO) and Spirulina platensis (SP), in apolipoprotein E knockout (ApoE−/−) mice, a well-established mouse model of atherosclerosis. Male ApoE−/− mice were fed a high-fat/high-cholesterol (HF/HC, 15% fat and 0.2% cholesterol by wt) control diet or a HF/HC diet supplemented with 5% (w/w) of NO or SP powder for 12 weeks. Plasma total cholesterol (TC) and triglycerides (TG) were measured, and livers were analyzed for histology and gene expression. Morphometric analysis for lesions and immunohistochemical analysis for CD68 were conducted in the aorta and the aortic root. NO supplementation significantly decreased plasma TC and TG, and liver TC, compared to control and SP groups. In the livers of NO-fed mice, less lipid droplets were present with a concomitant decrease in fatty acid synthase protein levels than the other groups. There was a significant increase in hepatic low-density lipoprotein receptor protein levels in SP-supplemented mice than in control and NO groups. Quantification of aortic lesions by en face analysis demonstrated that both NO and SP decreased aortic lesion development to a similar degree compared with control. While lesions in the aortic root were not significantly different between groups, the CD68-stained area in the aortic root was significantly lowered in BGA-fed mice than controls. In conclusion, both NO and SP supplementation decreased the development of atherosclerotic lesions, suggesting that they may be used as a natural product for atheroprotection. PMID:26566121

  6. The Apolipoprotein E (APOE) Gene Appears Functionally Monomorphic in Chimpanzees (Pan troglodytes)

    PubMed Central

    McIntosh, Annick M.; Bennett, Calvin; Dickson, Dara; Anestis, Stephanie F.; Watts, David P.; Webster, Timothy H.; Fontenot, M. Babette; Bradley, Brenda J.

    2012-01-01

    Background The human apolipoprotein E (APOE) gene is polymorphic, with three primary alleles (E2, E3, E4) that differ at two key non-synonymous sites. These alleles are functionally different in how they bind to lipoproteins, and this genetic variation is associated with phenotypic variation for several medical traits, including cholesterol levels, cardiovascular health, Alzheimer’s disease risk, and longevity. The relative frequencies of these alleles vary across human populations, and the evolution and maintenance of this diversity is much debated. Previous studies comparing human and chimpanzee APOE sequences found that the chimpanzee sequence is most similar to the human E4 allele, although the resulting chimpanzee protein might function like the protein coded for by the human E3 allele. However, these studies have used sequence data from a single chimpanzee and do not consider whether chimpanzees, like humans, show intra-specific and subspecific variation at this locus. Methodology and Principal Findings To examine potential intraspecific variation, we sequenced the APOE gene of 32 chimpanzees. This sample included 20 captive individuals representing the western subspecies (P. troglodytes verus) and 12 wild individuals representing the eastern subspecies (P. t. schweinfurthii). Variation in our resulting sequences was limited to one non-coding, intronic SNP, which showed fixed differences between the two subspecies. We also compared APOE sequences for all available ape genera and fossil hominins. The bonobo APOE protein is identical to that of the chimpanzee, and the Denisovan APOE exhibits all four human-specific, non-synonymous changes and appears functionally similar to the human E4 allele. Conclusions We found no coding variation within and between chimpanzee populations, suggesting that the maintenance of functionally diverse APOE polymorphisms is a unique feature of human evolution. PMID:23112842

  7. Head injury and risk of Alzheimer's disease by apolipoprotein E genotype.

    PubMed

    O'Meara, E S; Kukull, W A; Sheppard, L; Bowen, J D; McCormick, W C; Teri, L; Pfanschmidt, M; Thompson, J D; Schellenberg, G D; Larson, E B

    1997-09-01

    Head injury and apolipoprotein E (APOE)-epsilon 4 (e4) genotype have each been associated with increased risk of Alzheimer's disease. If APOE-e4 affects neuronal viability and branching, and if response to head injury differs in e4 patients, then the association between head injury and Alzheimer's disease may vary with the presence of the e4 allele. The authors examined this association in a case-control study conducted between 1987 and 1995 among enrollees of the Group Health Cooperative of Puget Sound, a health maintenance organization in Seattle, Washington. Proxy informants reported prior head injury with loss of consciousness for 32 of 349 patients with probable Alzheimer's disease and for 16 of 342 control subjects of similar age and sex who had been randomly selected from the same population (odds ratio (OR) = 2.1, 95% confidence interval (CI) 1.1-3.8). Elevated risk was observed among men (OR = 4.2, 95% CI 1.5-11.5) but not among women (OR = 1.1, 95% CI 0.5-2.6). No significant variation in the head injury-Alzheimer's disease risk relation by APOE-e4 genotype was found among 230 cases and 309 controls (OR = 3.1 (95% CI 0.7-14.6) for persons with at least one e4 allele and OR = 2.0 (95% CI 0.8-5.2) for those without e4). Neither age, education, race, type of proxy informant, nor duration of relationship with the proxy confounded the association. Head injury with loss of consciousness, although uncommon in this sample, was associated with increased risk of Alzheimer's disease. APOE-e4 was an independent risk factor which neither modified nor confounded the association. Susceptibility to Alzheimer's disease as conferred by APOE-e4 does not appear to increase the risk associated with head injury.

  8. Irisin protects against endothelial injury and ameliorates atherosclerosis in apolipoprotein E-Null diabetic mice.

    PubMed

    Lu, Junyan; Xiang, Guangda; Liu, Min; Mei, Wen; Xiang, Lin; Dong, Jing

    2015-12-01

    The circulating irisin increases energy expenditure and improves insulin resistance in mice and humans. The improvement of insulin resistance ameliorates atherosclerosis. Therefore, we hypothesized that irisin alleviates atherosclerosis in diabetes. Endothelial function was measured by acetylcholine-induced endothelium-dependent vasodilation using aortic rings in apolipoprotein E-Null (apoE(-/-)) streptozotocin-induced diabetic mice. Atherosclerotic lesion was evaluated by plaque area and inflammatory response in aortas. In addition, the endothelium-protective effects of irisin were also further investigated in primary human umbilical vein endothelial cells (HUVECs) in vitro. The in vivo experiments showed that irisin treatment significantly improved endothelial dysfunction, decreased endothelial apoptosis, and predominantly decreased atherosclerotic plaque area of both en face and cross sections when compared with normal saline-treated diabetic mice. Moreover, the infiltrating macrophages and T lymphocytes within plaque and the mRNA expression levels of inflammatory cytokines in aortas were also significantly reduced by irisin treatment in mice. The in vitro experiments revealed that irisin inhibited high glucose-induced apoptosis, oxidative stress and increased antioxidant enzymes expression in HUVECs, and pretreatment with LY294002, l-NAME, AMPK-siRNA or eNOS-siRNA, attenuated the protection of irisin on HUVECs apoptosis induced by high glucose. In addition, the in vivo and in vitro experiments showed that irisin increased the phosphorylation of AMPK, Akt and eNOS in aortas and cultured HUVECs. The present study indicates that systemic administration of irisin may be protected against endothelial injury and ameliorated atherosclerosis in apoE(-/-) diabetic mice. The endothelium-protective action of irisin was through activation of AMPK-PI3K-Akt-eNOS signaling pathway. Irisin could be therapeutic for atherosclerotic vascular diseases in diabetes. Copyright

  9. Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of apolipoprotein E deficient mice

    SciTech Connect

    Xiao, Hong-Bo; Lu, Xiang-Yang; Sun, Zhi-Liang; Zhang, Heng-Bo

    2011-12-15

    Recent studies show that osteopontin (OPN) and its receptor cluster of differentiation 44 (CD44) are two pro-inflammatory cytokines contributing to the development of atherosclerosis. The objective of this study was to explore the inhibitory effect of kaempferol, a naturally occurring flavonoid compound, on atherogenesis and the mechanisms involved. The experiments were performed in aorta and plasma from C57BL/6J control and apolipoprotein E-deficient (ApoE{sup -/-}) mice treated or not with kaempferol (50 or 100 mg/kg, intragastrically) for 4 weeks. Kaempferol treatment decreased atherosclerotic lesion area, improved endothelium-dependent vasorelaxation, and increased the maximal relaxation value concomitantly with decrease in the half-maximum effective concentration, plasma OPN level, aortic OPN expression, and aortic CD44 expression in ApoE{sup -/-} mice. In addition, treatment with kaempferol also significantly decreased reactive oxygen species production in mice aorta. The present results suggest that kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of ApoE{sup -/-} mice. -- Graphical abstract: Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of ApoE{sup -/-} mice. Highlights: Black-Right-Pointing-Pointer OPN-CD44 pathway plays a critical role in the development of atherosclerosis. Black-Right-Pointing-Pointer We examine lesion area, OPN and CD44 changes after kaempferol treatment. Black-Right-Pointing-Pointer Kaempferol treatment decreased atherosclerotic lesion area in ApoE{sup -/-} mice. Black-Right-Pointing-Pointer Kaempferol treatment decreased aortic OPN and CD44 expressions in ApoE{sup -/-} mice. Black-Right-Pointing-Pointer Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis.

  10. Hypoxanthine induces cholesterol accumulation and incites atherosclerosis in apolipoprotein E-deficient mice and cells.

    PubMed

    Ryu, Hye-Myung; Kim, You-Jin; Oh, Eun-Joo; Oh, Se-Hyun; Choi, Ji-Young; Cho, Jang-Hee; Kim, Chan-Duck; Park, Sun-Hee; Kim, Yong-Lim

    2016-11-01

    Reactive oxygen species (ROS) generation during purine metabolism is associated with xanthine oxidase and uric acid. However, the direct effect of hypoxanthine on ROS generation and atherosclerosis has not been evaluated. Smoking and heavy drinking are associated with elevated levels of hypoxanthine. In this study, we investigated the role of hypoxanthine on cholesterol synthesis and atherosclerosis development, particularly in apolipoprotein E (APOE)-deficient mice. The effect of hypoxanthine on the regulation of cholesterol synthesis and atherosclerosis were evaluated in Apoe knockout (KO) mice and cultured HepG2 cells. Hypoxanthine markedly increased serum cholesterol levels and the atherosclerotic plaque area in Apoe KO mice. In HepG2 cells, hypoxanthine increased intracellular ROS production. Hypoxanthine increased cholesterol accumulation and decreased APOE and ATP-binding cassette transporter A1 (ABCA1) mRNA and protein expression in HepG2 cells. Furthermore, H2 O2 also increased cholesterol accumulation and decreased APOE and ABCA1 expression. This effect was partially reversible by treatment with the antioxidant N-acetyl cysteine and allopurinol. Hypoxanthine and APOE knockdown using APOE-siRNA synergistically induced cholesterol accumulation and reduced APOE and ABCA1 expression. Hypoxanthine induces cholesterol accumulation in hepatic cells through alterations in enzymes that control lipid transport and induces atherosclerosis in APOE-deficient cells and mice. These effects are partially mediated through ROS produced in response to hypoxanthine. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  11. Apolipoprotein E4 association with metabolic syndrome depends on body fatness.

    PubMed

    Torres-Perez, Elena; Ledesma, Marta; Garcia-Sobreviela, Maria Pilar; Leon-Latre, Montserrat; Arbones-Mainar, Jose M

    2016-02-01

    The human Apolipoprotein E (APOE) gene is polymorphic. The APOE*4 allele is a risk factor for cardiovascular disease and could contribute to the development of the metabolic syndrome (MetS) as it may affect all MetS components. We hypothesize that the common APOE4 polymorphism differentially regulates MetS risk and that this association might be modulated by body fatness. We used body mass index (BMI) as surrogate of fatness and cross-sectionally studied the prevalence of MetS in 4408 middle-aged men of the Aragon Workers Health Study (AWHS). Our analysis revealed i) a gene dose-dependent association between APOE*4 allele and increased risk for MetS, ii) this association primarily derived from the overweight subjects. For these individuals, the MetS risk was higher in APOE*4 carriers than in non-carriers (Odds Ratio = 1.31; 95% CI, 1.03-1.67). Additionally, we examined 3908 healthy young individuals from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort, followed-up for 25 years. Compared with APOE*4 non-carriers, APOE*4 presence significantly increased the risk of developing MetS (Hazard Ratio, 1.12; 95% CI, 1.00-1.26). Again, an interplay between APOE*4 and the longitudinal development of fatness towards the onset of MetS occurred throughout the study. For individuals with BMI gain below the median, the cumulative onset rate of MetS was significantly higher in APOE*4 carriers than in the non-carriers (HR, 1.29; 95% CI, 1.07-1.55). Carrying APOE*4 alleles increases MetS in a dose-dependent manner, characterizing individual's APOE genotype might help identify at-risk subjects for preventive intervention. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Apolipoprotein E (APOE) ε4 and episodic memory decline in Alzheimer's disease: A review.

    PubMed

    El Haj, Mohamad; Antoine, Pascal; Amouyel, Philippe; Lambert, Jean-Charles; Pasquier, Florence; Kapogiannis, Dimitrios

    2016-05-01

    A growing body of research has examined the relationship between episodic memory decline, the cognitive hallmark of Alzheimer's disease (AD), and the presence of Apolipoprotein E ε4 (APOE ε4) allele, a major genetic risk factor for the disease. Our review attempts to summarize and critically evaluate this literature. We performed a systematic search for studies assessing episodic memory in AD patients who were genotyped for APOE ε4 and identified fourteen papers. Although most of these papers reported significant relationships between APOE ε4 and episodic memory decline in AD, some papers did not confirm this relationship. Our review links this controversy to the conflicting literature about the effects of APOE ε4 on general cognitive functioning in AD. We identify several shortcoming and limitations of the research on the relationship between APOE ε4 and episodic memory in AD, such as small sample sizes, non-representative populations, lack of comparison of early-onset vs. late-onset disease, and lack of comparison among different genotypes that include APOE ε4 (i.e., zero, one, or two ε4 alleles). Another major shortcoming of the reviewed literature was the lack of comprehensive evaluation of episodic memory decline, since episodic memory was solely evaluated with regard to encoding and retrieval, omitting evaluation of core episodic features that decline in AD, such as context recall (e.g., how, where, and when an episodic event has occurred) and subjective experience of remembering (e.g., reliving, emotion and feeling during episodic recollection). Future research taking these limitations into consideration could illuminate the nature of the relationship between APOE ε4 and episodic memory decline in AD. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Apolipoprotein E and traumatic brain injury in a military population: evidence of a neuropsychological compensatory mechanism?

    PubMed Central

    Han, S Duke; Drake, Angela I; Cessante, Lynne M; Jak, Amy J; Houston, Wes S; Delis, Dean C; Filoteo, J Vincent; Bondi, Mark W

    2007-01-01

    Objective Although research has implicated the apolipoprotein E (APOE) epsilon‐4 genotype as having a negative effect on neuropsychological outcomes following traumatic brain injury (TBI), the potentially negative role of the ε4 allele on TBI outcomes has recently been challenged. In light of this debate, the present study served to examine the role of APOE genotype on neuropsychological outcomes approximately 1 month following mild to moderate TBI in a military population. Because of the well documented role of the APOE‐ε4 allele in increasing the risk of Alzheimer's disease, we predicted that persons with the APOE‐ε4 genotype would display relatively greater deficits in cognition than their non‐ε4 counterparts. Methods 78 participants were consecutively recruited following a mild to moderate TBI and were divided into two groups based on the presence or absence of an APOE ε4 allele. Groups were comparable on demographic characteristics and psychosocial outcomes. Participants were administered a comprehensive neuropsychological battery. Results Analyses revealed comparable performances on most neuropsychological measures and better performances by ε4 carriers on select measures of attention, executive functioning and episodic memory encoding. Furthermore, differences remained after accounting for the effects of TBI severity. Conclusions Evidence from these analyses supports current literature refuting the notion of relatively poorer neuropsychological functioning associated with the APOE‐ε4 genotype among young adult participants shortly following mild or moderate brain injury. Neuropsychological performance differences by APOE genotype following TBI are discussed in terms of the importance of considering severity of injury, timing of postinjury assessment and possible neurocognitive compensatory mechanisms. PMID:17287237

  14. Association between Apolipoprotein E genotype and cerebral palsy is not confirmed in a Caucasian population.

    PubMed

    McMichael, Gai L; Gibson, Catherine S; Goldwater, Paul N; Haan, Eric A; Priest, Kevin; Dekker, Gustaaf A; MacLennan, Alastair H

    2008-11-01

    Apolipoprotein E (APOE) plays a significant role in lipid metabolism and has been implicated in the growth and repair of injured neurons. Two small studies have suggested an association between APOE genotype and cerebral palsy. We investigated if APOE genotype is associated with an increased risk for cerebral palsy, influences the type of cerebral palsy or interacts with prenatal viral infection to influence risk of cerebral palsy. The population-based case-control study comprised newborn screening cards of 443 Caucasian patients with cerebral palsy and 883 Caucasian matched controls. APOE genotyping was performed on DNA extracted from dried blood spots. Allelic and genotypic frequencies did not differ between cases and controls and combined frequencies were 0.10 (epsilon2), 0.76 (epsilon3), 0.14 (epsilon4), 0.03 (epsilon2/epsilon2), 0.10 (epsilon2/epsilon3), 0.03 (epsilon2/epsilon4), 0.02 (epsilon4/epsilon4), 0.21 (epsilon3/epsilon4), 0.61 (epsilon3/epsilon3). APOE genotype was correlated with cerebral palsy, type of cerebral palsy, gestation at birth and the presence of viral nucleic acids detected in previous work. Analysis by gestational age (all gestational ages, >/=37, 32-36 and <32 weeks) and type of cerebral palsy (all types, diplegia, hemiplegia and quadriplegia) showed no association between APOE genotype and cerebral palsy in this Caucasian population. An association between prenatal viral infection, APOE genotype and cerebral palsy was not demonstrated. These results did not confirm an association between APOE genotype, cerebral palsy, type of cerebral palsy and prenatal infection in a Caucasian population. Given the low frequency of APOE epsilon2 and some of the heterozygote and homozygote combinations in this study, a larger study is assessing this further.

  15. Angiotensin Converting Enzyme Inhibitors and Alzheimer Disease in the Presence of the Apolipoprotein E4 Allele

    PubMed Central

    Qiu, Wendy Wei Qiao; Lai, Angela; Mon, Timothy; Mwamburi, Mkaya; Taylor, Warren; Rosenzweig, James; Kowall, Neil; Stern, Robert; Zhu, Haihao; Steffens, David C.

    2013-01-01

    Objective The effect of angiotensin converting enzyme (ACE) inhibitors on Alzheimer disease (AD) remains unclear, with conflicting results reported. We studied the interaction of the Apolipoprotein E (ApoE) genotype and ACE inhibitors on AD. Methods This was a cross-sectional study of homebound elderly with an AD diagnosis and documentation of medications taken. ApoE genotype was determined. Results A total of 355 subjects with status on ApoE alleles and cognitive diagnoses were studied. The average age (mean ± SD) of this population was 73.3 ± 8.3 years old, and 73% were female. Cross-sectionally, there was no difference in the number of AD cases between ApoE4 carriers and ApoE4 non-carriers or between ACE inhibitor users and non-users in the homebound elderly. ApoE4 carriers treated with ACE inhibitors, however, had more diagnoses of AD compared with those who did not have the treatment (28% versus 6%, p = 0.01) or ApoE4 non-carriers treated with an ACE inhibitor (28% versus 10%, p = 0.03). ACE inhibitor use was associated with AD diagnosis only in the presence of an E4 allele. Using multivariate logistic regression analysis, we found that in diagnosed AD cases there was a significant interaction between ApoE4 and ACE inhibitor use (odds ratio: 20.85; 95% confidence interval: 3.08–140.95; p = 0.002) after adjusting for age, sex, ethnicity, and education. Conclusion The effects of ACE inhibitors on AD may be different depending on ApoE genotype. A prospective study is needed to determine whether ACE inhibitor use accelerates or poorly delays AD development in ApoE4 carriers compared with ApoE4 non-carriers. PMID:23567418

  16. Angiotensin converting enzyme inhibitors and Alzheimer disease in the presence of the apolipoprotein E4 allele.

    PubMed

    Qiu, Wendy Wei Qiao; Lai, Angela; Mon, Timothy; Mwamburi, Mkaya; Taylor, Warren; Rosenzweig, James; Kowall, Neil; Stern, Robert; Zhu, Haihao; Steffens, David C

    2014-02-01

    The effect of angiotensin converting enzyme (ACE) inhibitors on Alzheimer disease (AD) remains unclear, with conflicting results reported. We studied the interaction of the Apolipoprotein E (ApoE) genotype and ACE inhibitors on AD. This was a cross-sectional study of homebound elderly with an AD diagnosis and documentation of medications taken. ApoE genotype was determined. A total of 355 subjects with status on ApoE alleles and cognitive diagnoses were studied. The average age (mean ± SD) of this population was 73.3 ± 8.3 years old, and 73% were female. Cross-sectionally, there was no difference in the number of AD cases between ApoE4 carriers and ApoE4 non-carriers or between ACE inhibitor users and non-users in the homebound elderly. ApoE4 carriers treated with ACE inhibitors, however, had more diagnoses of AD compared with those who did not have the treatment (28% versus 6%, p = 0.01) or ApoE4 non-carriers treated with an ACE inhibitor (28% versus 10%, p = 0.03). ACE inhibitor use was associated with AD diagnosis only in the presence of an E4 allele. Using multivariate logistic regression analysis, we found that in diagnosed AD cases there was a significant interaction between ApoE4 and ACE inhibitor use (odds ratio: 20.85; 95% confidence interval: 3.08-140.95; p = 0.002) after adjusting for age, sex, ethnicity, and education. The effects of ACE inhibitors on AD may be different depending on ApoE genotype. A prospective study is needed to determine whether ACE inhibitor use accelerates or poorly delays AD development in ApoE4 carriers compared with ApoE4 non-carriers. Copyright © 2014. Published by Elsevier Inc.

  17. Blue-Green Algae Inhibit the Development of Atherosclerotic Lesions in Apolipoprotein E Knockout Mice.

    PubMed

    Ku, Chai Siah; Kim, Bohkyung; Pham, Tho X; Yang, Yue; Wegner, Casey J; Park, Young-Ki; Balunas, Marcy; Lee, Ji-Young

    2015-12-01

    Hyperlipidemia and inflammation contribute to the development of atherosclerotic lesions. Our objective was to determine antiatherogenic effect of edible blue-green algae (BGA) species, that is, Nostoc commune var. sphaeroides Kützing (NO) and Spirulina platensis (SP), in apolipoprotein E knockout (ApoE(-/-)) mice, a well-established mouse model of atherosclerosis. Male ApoE(-/-) mice were fed a high-fat/high-cholesterol (HF/HC, 15% fat and 0.2% cholesterol by wt) control diet or a HF/HC diet supplemented with 5% (w/w) of NO or SP powder for 12 weeks. Plasma total cholesterol (TC) and triglycerides (TG) were measured, and livers were analyzed for histology and gene expression. Morphometric analysis for lesions and immunohistochemical analysis for CD68 were conducted in the aorta and the aortic root. NO supplementation significantly decreased plasma TC and TG, and liver TC, compared to control and SP groups. In the livers of NO-fed mice, less lipid droplets were present with a concomitant decrease in fatty acid synthase protein levels than the other groups. There was a significant increase in hepatic low-density lipoprotein receptor protein levels in SP-supplemented mice than in control and NO groups. Quantification of aortic lesions by en face analysis demonstrated that both NO and SP decreased aortic lesion development to a similar degree compared with control. While lesions in the aortic root were not significantly different between groups, the CD68-stained area in the aortic root was significantly lowered in BGA-fed mice than controls. In conclusion, both NO and SP supplementation decreased the development of atherosclerotic lesions, suggesting that they may be used as a natural product for atheroprotection.

  18. Apolipoprotein E expression and behavioral toxicity of high charge, high energy (HZE) particle radiation

    NASA Technical Reports Server (NTRS)

    Higuchi, Yoshinori; Nelson, Gregory A.; Vazquez, Marcelo; Laskowitz, Daniel T.; Slater, James M.; Pearlstein, Robert D.

    2002-01-01

    Apolipoprotein E (apoE) is a lipid binding protein that plays an important role in tissue repair following brain injury. In the present studies, we have investigated whether apoE affects the behavioral toxicity of high charge, high energy (HZE) particle radiation. METHODS: Sixteen male apoE knockout (KO) mice and sixteen genetically matched wild-type (WT) C57BL mice were used in this experiment. Half of the KO and half of the WT animals were irradiated with 600 MeV/amu iron particles (2 Gy whole body). The effect of irradiation on motor coordination and stamina (Rotarod test), exploratory behavior (open field test), and spatial working and reference memory (Morris water maze) was assessed. ROTAROD TEST: Performance was adversely affected by radiation exposure in both KO and WT groups at 30 d after irradiation. By 60 d after radiation, the radiation effect was lost in WT, but still apparent in irradiated KO mice. OPEN FIELD TEST: Radiation reduced open field exploratory activity 14, 28, 56, 84, and 168 d after irradiation of KO mice, but had no effect on WT mice. MORRIS WATER MAZE: Radiation adversely affected spatial working memory in the KO mice, but had no discernible effect in the WT mice as assessed 180 d after irradiation. In contrast, irradiated WT mice showed marked impairment of spatial reference memory in comparison to non-irradiated mice, while no effect of radiation was observed in KO mice. CONCLUSIONS: These studies show that apoE expression influences the behavioral toxicity of HZE particle radiation and suggest that apoE plays a role in the repair/recovery from radiation injury of the CNS. ApoE deficiency may exacerbate the previously reported effects of HZE particle radiation in accelerating the brain aging process.

  19. Effects of Apolipoprotein E Isoforms in Diabetic Nephropathy of Chinese Type 2 Diabetic Patients

    PubMed Central

    Ma, Liang; Han, ChengWu; Liu, Qian; Cong, Xiao; Xu, YaPing; Zhao, TingTing

    2017-01-01

    Diabetic nephropathy (DN) is one of the major chronic complications of diabetes. Genetic polymorphism of Apolipoprotein E (ApoE) has been proposed to participating in DN. The purpose of the study was to evaluate the relationship between ApoE genetic polymorphism and the presence of DN in Chinese type 2 diabetic patients. We studied 845 diabetic patients who were divided into DN group (n = 429) and control group (n = 416). ApoE genotype was determined by ApoE genotyping chip and the plasmatic biochemical characterization was performed on all subjects. There were differences (P < 0.001) in HbA1c, creatinine, and urinary albumin between the two groups. The ApoE ε2 allelic frequency was 7.69% in DN group versus 3.49% in control group (OR = 2.22, 95% CI = 1.41–3.47, and P < 0.05), as expected, ApoE E2/E2 and E2/E3 genotype frequency were higher in DN group (13.75% versus 6.49%, P < 0.05). The ApoE ε4 allelic frequency was 7.93% in DN group versus 11.54% in control group (OR = 0.70, 95% CI = 0.50–0.97, and P < 0.05), and DN group presented a lower frequency of ApoE E3/E4 and E4/E4 genotype frequency (14.91% versus 19.96%, P < 0.05). These results suggest ApoE ε2 allele may be a risk factor; however ApoE ε4 allele may play a protective role of DN in Chinese type 2 diabetic patients. PMID:28326331

  20. Aspirin-triggered lipoxin A4 inhibits atherosclerosis progression in apolipoprotein E(-/-) mice.

    PubMed

    Petri, Marcelo H; Laguna-Fernandez, Andrés; Arnardottir, Hildur; Wheelock, Craig E; Perretti, Mauro; Hansson, Göran K; Bäck, Magnus

    2017-01-10

    Atherosclerosis is characterized by a chronic non-resolving inflammation in the arterial wall. Aspirin-triggered lipoxin A4 (ATL) is a potent anti-inflammatory mediator, involved in the resolution of inflammation. However, the therapeutic potential of immune targeting by means of ATL in atherosclerosis has not previously been explored. The aim of the present study was to determine the effects of ATL and its receptor Fpr2 on atherosclerosis development and progression in apolipoprotein E deficient (ApoE(-/-) ) mice. ApoE(-/-)  × Fpr2(+/+) and ApoE(-/-)  × Fpr2(-/-) mice were generated. Four-week-old mice fed a high-fat diet for 4 weeks and 16-week-old mice fed chow diet received osmotic pumps containing either vehicle or ATL for 4 weeks. Atherosclerotic lesion size and cellular composition were measured in the aortic root and thoracic aorta. Lipid levels and leukocyte counts were measured in blood and mRNA was isolated from abdominal aorta and spleen. ATL blocked atherosclerosis progression in the aortic root and thoracic aorta of ApoE(-/-) mice. In addition, ATL reduced macrophage infiltration and apoptotic cells in atherosclerotic lesions. The mRNA levels of several cytokines and chemokines in the spleen and aorta were reduced by ATL, whereas circulating leukocyte levels were unchanged. The ATL-induced athero-protection was absent in ApoE(-/-) mice lacking the Fpr2 receptor. ATL blocked atherosclerosis progression by means of an Fpr2-mediated reduced local and systemic inflammation. These results suggest this anti-inflammatory and pro-resolving agent has therapeutic potential for the treatment of atherosclerosis. © 2017 The British Pharmacological Society.

  1. [Polymorphism of the apolipoprotein E gene (APOE) in the populations of Russia and neighboring countries].

    PubMed

    Borinskaia, S A; Kal'ina, N R; Sanina, E D; Kozhekbaeva, Zh M; Gupalo, E Iu; Garmash, I V; Ogurtsov, P P; Parshukova, O N; Boĭko, S G; Veselovskiĭ, E M; Vershubskaia, G G; Kozlov, A I; Rogaev, E I; Iankovskiĭ, N K

    2007-10-01

    Allele and genotype frequencies for the locus encoding apolipoprotein E, involved in the regulation of lipid metabolism (APOE), were evaluated in 16 populations representing 12 ethnic groups (a total of 1103 subjects) from Russia and neighboring countries. In the populations examined, the frequencies of allele epsilon4, which is the risk factor of Alzheimer's disease and coronary heart disease, varied from less than 5 to more than 20%, while the variation of the major epsilon3 allele in these populations ranged from less than 75 to 95%. The frequencies of alleles epsilon3 and epsilon4 were 0.714 and 0.205 in Saami, 0.734 and 0.149 in Maris, 0.841 and 0.122 in Evenks, 0.788 and 0.163 in Buryats, 0.764 and 0.202 in Chukchi, 0.875 and 0.075 in Iranians, 0.956 and 0.044 in mountain-dwellers of the Pamirs, 0.771 and 0.094 in Ukrainians, and 0.795 and 0.091 in Belarussians, respectively. In Russians from different regions of the country, the frequencies of these alleles were 0.728 and 0.139 (Kostroma), 0.795 and 0.105 (Moscow), 0.857 and 0.092 (Rostov-on-Don), and 0.824 and 0.083 (Krasnodar), respectively. The latitudinal distribution of the APOE epsilon3 and epsilon4 allele frequencies in the populations examined was comparable to the frequency distribution pattern of these alleles in other populations of Eurasia.

  2. AN APOLIPOPROTEIN E4 FRAGMENT CAN PROMOTE INTRACELLULAR ACCUMULATION OF AMYLOID PEPTIDE BETA 42

    PubMed Central

    Dafnis, Ioannis; Stratikos, Efstratios; Tzinia, Athina; Tsilibary, Effie C.; Zannis, Vassilis I.; Chroni, Angeliki

    2010-01-01

    Apolipoprotein E (apoE) plays a crucial role in lipid transport in circulation and the brain. The apoE4 isoform is a major risk factor for Alzheimer's disease (AD). ApoE4 is more susceptible to proteolysis than other apoE isoforms and apoE4 fragments have been found in brains of AD patients. These apoE4 fragments have been hypothesized to be involved in the pathogenesis of AD, although the mechanism is not clear. In this study we examined the effect of lipid-free apoE4 on amyloid precursor protein (APP) processing and Aβ40 and Aβ42 levels in human neuroblastoma SK-N-SH cells. We discovered that a specific apoE4 fragment, apoE4[Δ(166-299)], can promote the cellular uptake of extracellular Aβ40 and Aβ42 either generated after APP transfection or added exogenously. A longer length fragment, apoE4[Δ(186-299)], or full-length apoE4 failed to elicit this effect. ApoE4[Δ(166-299)] effected a 20% reduction of cellular sphingomyelin levels, as well as changes in cellular membrane micro-fluidity. Following uptake, approximately 50% of Aβ42 remained within the cell for at least 24h, and led to increased formation of reactive oxygen species. Overall, our findings suggest a direct link between two early events in the pathogenesis of AD, apoE4 proteolysis and intraneuronal presence of Aβ. PMID:20412390

  3. Age-Related Effects of the Apolipoprotein E Gene on Brain Function.

    PubMed

    Matura, Silke; Prvulovic, David; Hartmann, Daniel; Scheibe, Monika; Sepanski, Beate; Butz, Marius; Oertel-Knöchel, Viola; Knöchel, Christian; Karakaya, Tarik; Fußer, Fabian; Hattingen, Elke; Pantel, Johannes

    2016-03-16

    The apolipoprotein E (ApoE) ɛ4 allele is a well-established genetic risk factor for sporadic Alzheimer's disease. Some evidence suggests a negative role of the ApoE ɛ4 allele for cognitive performance in late life, while beneficial effects on cognition have been shown in young age. We investigated age-related effects of the ApoE gene on brain function by assessing cognitive performance, as well as functional activation patterns during retrieval of Face-Name pairs in a group of young (n = 50; age 26.4±4.6 years, 25 ɛ4 carriers) and old (n = 40; age 66.1±7.0 years, 20 ɛ4 carriers) participants. A cross-sectional factorial design was used to examine the effects of age, ApoE genotype, and their interaction on both cognitive performance and the blood oxygenation level dependent (BOLD) brain response during retrieval of Face-Name pairs. While there were no genotype-related differences in cognitive performance, we found a significant interaction of age and ApoE genotype on task-related activation bilaterally in anterior cingulate gyrus and superior frontal gyrus, as well as left and right insula. Old age was associated with increased activity in ɛ4 carriers. The increased BOLD response in old ɛ4 carriers during retrieval could indicate a neurocognitive disadvantage associated with the ɛ4 allele with increasing age. Furthermore, recruitment of neuronal resources resulted in enhanced memory performance in young ɛ4 carriers, pointing to a better neurofunctional capacity associated with the ApoE4 genotype in young age.

  4. Apolipoprotein E ε4 modulates functional brain connectome in Alzheimer's disease.

    PubMed

    Wang, Jinhui; Wang, Xiao; He, Yi; Yu, Xin; Wang, Huali; He, Yong

    2015-05-01

    The apolipoprotein E (APOE) ɛ4 allele is a well-established genetic risk factor for Alzheimer's disease (AD). Recent research has demonstrated an APOE ɛ4-mediated modulation of intrinsic functional brain networks in cognitively normal individuals. However, it remains largely unknown whether and how APOE ɛ4 affects the brain's functional network architecture in patients with AD. Using resting-state functional MRI and graph-theory approaches, we systematically investigated the topological organization of whole-brain functional networks in 16 APOE ɛ4 carriers and 26 matched noncarriers with AD at three levels: global whole-brain, intermediate module, and regional node/connection. Neuropsychological analysis showed that the APOE ɛ4 carriers performed worse on delayed memory but better on a late item generation of a verbal fluency task (associated with executive function) than noncarriers. Whole-brain graph analyses revealed that APOE ɛ4 significantly disrupted whole-brain topological organization as characterized by (i) reduced parallel information transformation efficiency; (ii) decreased intramodular connectivity within the posterior default mode network (pDMN) and intermodular connectivity of the pDMN and executive control network (ECN) with other neuroanatomical systems; and (iii) impaired functional hubs and their rich-club connectivities that primarily involve the pDMN, ECN, and sensorimotor systems. Further simulation analysis indicated that these altered connectivity profiles of the pDMN and ECN largely accounted for the abnormal global network topology. Finally, the changes in network topology exhibited significant correlations with the patients' cognitive performances. Together, our findings suggest that the APOE genotype modulates large-scale brain networks in AD and shed new light on the gene-connectome interaction in this disease.

  5. Apolipoprotein E genotyping using PCR-GoldMag lateral flow assay and its clinical applications

    PubMed Central

    Lian, Ting; Hui, Wenli; Li, Xianying; Zhang, Chao; Zhu, Juanli; Li, Rui; Wan, Yinsheng; Cui, Yali

    2016-01-01

    A polymerase chain reaction-gold magnetic nanoparticles lateral flow assay (PCR-GoldMag LFA) has been developed via integrating multiplex amplification refractory mutation system PCR (multi-ARMS-PCR) with GoldMag-based LFA for the visual detection of single-nucleotide polymorphisms (SNPs). This assay was applied to genotype Apolipoprotein E (ApoE). ApoE genotyping is important due to the predictive value for the development of coronary artery disease and Alzheimer's disease. The method requires two steps: i) Simultaneous amplifications of the two polymorphic codons (ApoE 158 and 112), performed in separated reactions using multi-ARMS-PCR; and ii) detection of the wild-type and mutant PCR products via dual immunoreactions, which can be performed in ~5 min. Within two LFAs, anti-digoxin antibody-conjugated GoldMag probes bind digoxin-labeled wild-type PCR products, and anti-fluorescein isothiocyanate (FITC) antibody-conjugated GoldMag probes bind FITC-labeled mutant PCR products. All PCR products are biotin labeled and are detected by streptavidin-coated regions on the LFA strip, resulting in a red color. The current approach is capable of detecting the SNPs of ApoE in ~1.5 h, with a broad detection range from 10–1,000 ng of genomic DNA. Thus, the present protocol may facilitate simple, fast and cost-effective screening for important SNPs, as demonstrated by the evaluation of the prevalence of ApoE variants in a Han Chinese cohort. PMID:27665864

  6. Plasma biomarkers associated with the apolipoprotein E genotype and Alzheimer disease.

    PubMed

    Soares, Holly D; Potter, William Z; Pickering, Eve; Kuhn, Max; Immermann, Frederick W; Shera, David M; Ferm, Mats; Dean, Robert A; Simon, Adam J; Swenson, Frank; Siuciak, Judith A; Kaplow, June; Thambisetty, Madhav; Zagouras, Panayiotis; Koroshetz, Walter J; Wan, Hong I; Trojanowski, John Q; Shaw, Leslie M

    2012-10-01

    A blood-based test that could be used as a screen for Alzheimer disease (AD) may enable early intervention and better access to treatment. To apply a multiplex immunoassay panel to identify plasma biomarkers of AD using plasma samples from the Alzheimer's Disease Neuroimaging Initiative cohort. Cohort study. The Biomarkers Consortium Alzheimer's Disease Plasma Proteomics Project. Plasma samples at baseline and at 1 year were analyzed from 396 (345 at 1 year) patients with mild cognitive impairment, 112 (97 at 1 year) patients with AD, and 58 (54 at 1 year) healthy control subjects. Multivariate and univariate statistical analyses were used to examine differences across diagnostic groups and relative to the apolipoprotein E (ApoE) genotype. Increased levels of eotaxin 3, pancreatic polypeptide, and N-terminal protein B-type brain natriuretic peptide were observed in patients, confirming similar changes reported in cerebrospinal fluid samples of patients with AD and MCI. Increases in tenascin C levels and decreases in IgM and ApoE levels were also observed. All participants with Apo ε3/ε4 or ε4/ε4 alleles showed a distinct biochemical profile characterized by low C-reactive protein and ApoE levels and by high cortisol, interleukin 13, apolipoprotein B, and gamma interferon levels. The use of plasma biomarkers improved specificity in differentiating patients with AD from controls, and ApoE plasma levels were lowest in patients whose mild cognitive impairment had progressed to dementia. Plasma biomarker results confirm cerebrospinal fluid studies reporting increased levels of pancreatic polypeptide and N-terminal protein B-type brain natriuretic peptide in patients with AD and mild cognitive impairment. Incorporation of plasma biomarkers yielded high sensitivity with improved specificity, supporting their usefulness as a screening tool. The ApoE genotype was associated with a unique biochemical profile irrespective of diagnosis, highlighting the importance of

  7. Radiative-SPR platform for the detection of apolipoprotein E for use in medical diagnostics

    NASA Astrophysics Data System (ADS)

    Sciacca, Beniamino; Francois, Alexandre; Penno, Megan A. S.; Brazzatti, Julie A.; Klingler-Hoffmann, Manuela; Hoffmann, Peter; Monro, Tanya M.

    2012-03-01

    Surface Plasmon Resonance (SPR) based sensors enable the rapid, label-free and highly sensitive detection of a large range of biomolecules. We have previously shown that, using silver coated optical fibres with an high surface roughness, a re-scattering of the surface plasmons is possible, turning SPR into a radiative process. This approach overcomes limitations associated with current SPR technologies such as the tight tolerance on the metallic coating thickness, and results in a more compact, versatile, robust and cost-effective approach. However, the specific detection of small molecules is a challenge in SPR systems, regardless of the SPR architecture that is used. This new sensing platform, which has proved effective for the detection of large molecules such as viruses, is now demonstrated to be able to detect small proteins thanks to an improved surface functionalization procedure, a key point for reliable and robust immunosensors. Avidin, a tetrameric biotin-binding protein, was used to link biotinylated antibodies to the biotinylated surface, with a given orientation, to enable efficient sensing of the analyte. This approach may offer significant advantages compared to protein A surface functionalization strategies such as a limited cross reactivity with free IgG antibodies in clinical samples. We demonstrate that by bringing together this novel emission-based fibre SPR platform, with an improved surface functionalization process, is possible to rapidly and specifically detect human apolipoprotein E, a low molecular weight protein (~39kDa) known to be involved in cardiovascular diseases, in Alzheimer's disease and in gastric cancer. The results obtained clearly show that this new sensing platform has the potential to serve as a tool for point-of-decision medical diagnostics.

  8. Endothelial Surface Layer Degradation by Chronic Hyaluronidase Infusion Induces Proteinuria in Apolipoprotein E-Deficient Mice

    PubMed Central

    Kuikhoven, Mayella; Heeneman, Sylvia; Lutgens, Esther; Gijbels, Marion J. J.; Nieuwdorp, Max; Peutz, Carine J.; Stroes, Erik S. G.; Vink, Hans; van den Berg, Bernard M.

    2010-01-01

    Objective Functional studies show that disruption of endothelial surface layer (ESL) is accompanied by enhanced sensitivity of the vasculature towards atherogenic stimuli. However, relevance of ESL disruption as causal mechanism for vascular dysfunction remains to be demonstrated. We examined if loss of ESL through enzymatic degradation would affect vascular barrier properties in an atherogenic model. Methods Eight week old male apolipoprotein E deficient mice on Western-type diet for 10 weeks received continuous active or heat-inactivated hyaluronidase (10 U/hr, i.v.) through an osmotic minipump during 4 weeks. Blood chemistry and anatomic changes in both macrovasculature and kidneys were examined. Results Infusion with active hyaluronidase resulted in decreased ESL (0.32±0.22 mL) and plasma volume (1.03±0.18 mL) compared to inactivated hyaluronidase (0.52±0.29 mL and 1.28±0.08 mL, p<0.05 respectively).Active hyaluronidase increased proteinuria compared to inactive hyaluronidase (0.27±0.02 vs. 0.15±0.01 µg/µg protein/creatinin, p<0.05) without changes in glomerular morphology or development of tubulo-interstitial inflammation. Atherosclerotic lesions in the aortic branches showed increased matrix production (collagen, 32±5 vs. 18±3%; glycosaminoglycans, 11±5 vs. 0.1±0.01%, active vs. inactive hyaluronidase, p<0.05). Conclusion ESL degradation in apoE deficient mice contributes to reduced increased urinary protein excretion without significant changes in renal morphology. Second, the induction of compositional changes in atherogenic plaques by hyaluronidase point towards increased plaque vulnerability. These findings support further efforts to evaluate whether ESL restoration is a valuable target to prevent (micro) vascular disease progression. PMID:21170388

  9. Apolipoprotein E4 allele as a predictor of cholinergic deficits and treatment outcome in Alzheimer disease.

    PubMed Central

    Poirier, J; Delisle, M C; Quirion, R; Aubert, I; Farlow, M; Lahiri, D; Hui, S; Bertrand, P; Nalbantoglu, J; Gilfix, B M

    1995-01-01

    Apolipoprotein E (apoE) is critical in the modulation of cholesterol and phospholipid transport between cells of different types. Human apoE is a polymorphic protein with three common alleles, APO epsilon 2, APO epsilon 3, and APO epsilon 4. ApoE4 is associated with sporadic and late-onset familial Alzheimer disease (AD). Gene dose was shown to have an effect on risk of developing AD, age of onset, accumulation of senile plaques in the brain, and reduction of choline acetyltransferase (ChAT) activity in the hippocampus of AD subjects. To characterize the possible impact of the apoE4 allele on cholinergic markers in AD, we examined the effect of apoE4 allele copy number on pre- and postsynaptic markers of cholinergic activity. ApoE4 allele copy number showed an inverse relationship with residual brain ChAT activity and nicotinic receptor binding sites in both the hippocampal formation and the temporal cortex of AD subjects. AD cases lacking the apoE4 allele showed ChAT activities close or within age-matched normal control values. The effect of the apoE4 allele on cholinomimetic drug responsiveness was assessed next in a group (n = 40) of AD patients who completed a double-blind, 30-week clinical trial of the cholinesterase inhibitor tacrine. Results showed that > 80% of apoE4-negative AD patients showed marked improvement after 30 weeks as measured by the AD assessment scale (ADAS), whereas 60% of apoE4 carriers had ADAS scores that were worse compared to baseline. These results strongly support the concept that apoE4 plays a crucial role in the cholinergic dysfunction associated with AD and may be a prognostic indicator of poor response to therapy with acetylcholinesterase inhibitors in AD patients. Images Fig. 2 PMID:8618881

  10. Amyloid mediates the association of apolipoprotein E e4 allele to cognitive function in older people

    PubMed Central

    Bennett, D; Schneider, J; Wilson, R; Bienias, J; Berry-Kravis, E; Arnold, S

    2005-01-01

    Background: The neurobiological changes underlying the association of the apolipoprotein E (APOE) e4 allele with level of cognition are poorly understood. Objective: To test the hypothesis that amyloid load can account for (mediate) the association of the APOE e4 allele with level of cognition assessed proximate to death. Methods: There were 44 subjects with clinically diagnosed Alzheimer's disease and 50 without dementia, who had participated in the Religious Orders Study. They underwent determination of APOE allele status, had comprehensive cognitive testing in the last year of life, and brain autopsy at death. The percentage area of cortex occupied by amyloid beta and the density of tau positive neurofibrillary tangles were quantified from six brain regions and averaged to yield summary measures of amyloid load and neurofibrillary tangles. Multiple regression analyses were used to examine whether amyloid load could account for the effect of allele status on level of cognition, controlling for age, sex, and education. Results: Possession of at least one APOE e4 allele was associated with lower level of cognitive function proximate to death (p = 0.04). The effect of the e4 allele was reduced by nearly 60% and was no longer significant after controlling for the effect of amyloid load, whereas there was a robust inverse association between amyloid and cognition (p = 0.001). Because prior work had suggested that neurofibrillary tangles could account for the association of amyloid on cognition, we next examined whether amyloid could account for the effect of allele status on tangles. In a series of regression analyses, e4 was associated with density of tangles (p = 0.002), but the effect of the e4 allele was reduced by more than 50% and was no longer significant after controlling for the effect of amyloid load. Conclusion: These findings are consistent with a sequence of events whereby the e4 allele works through amyloid deposition and subsequent tangle formation to

  11. Apolipoprotein E gene associations in age-related macular degeneration: the Melbourne Collaborative Cohort Study.

    PubMed

    Adams, Madeleine K M; Simpson, Julie A; Richardson, Andrea J; English, Dallas R; Aung, Khin Zaw; Makeyeva, Galina A; Guymer, Robyn H; Giles, Graham G; Hopper, John; Robman, Liubov D; Baird, Paul N

    2012-03-15

    The apolipoprotein E gene (APOE) has been found to be associated with age-related macular degeneration (AMD). Reported associations have been questioned, as they are opposite those for Alzheimer's disease and cardiovascular disease. The authors examined associations between APOE genotype and AMD using a case-control study (2,287 cases and 2,287 controls individually matched on age, sex, and country of origin) nested within Melbourne Collaborative Cohort Study participants aged 48-86 years at AMD detection. The odds ratio for early AMD among participants with ε2-containing genotypes (ε2ε2/ε2ε3/ε2ε4) was 1.32 (95% confidence interval (CI): 1.11, 1.58; P = 0.002) versus persons with genotype ε3ε3. Associations with early AMD varied by smoking status; ε2-containing genotypes were positively associated with early AMD for never and previous smokers (never smokers: odds ratio (OR) = 1.40, 95% CI: 1.12, 1.76 (P = 0.003); previous smokers: OR = 1.39, 95% CI: 1.00, 1.93 (P = 0.05)) but not for current smokers (OR = 0.66, 95% CI: 0.34, 1.30 (P = 0.2; interaction P = 0.05). The ε4-containing genotype group (ε3ε4/ε4ε4) had an inverse association with early AMD among current smokers only (OR = 0.41, 95% CI: 0.22, 0.77 (P = 0.005)). These results highlight the importance of stratifying by smoking status in elderly populations. Smokers who survive to old age may be more likely to possess unknown genotypes which modify exposure-disease associations.

  12. Leisure activities, apolipoprotein E e4 status, and the risk of dementia.

    PubMed

    Yang, Sheng-Ying; Weng, Pei-Hsuan; Chen, Jen-Hau; Chiou, Jeng-Min; Lew-Ting, Chih-Yin; Chen, Ta-Fu; Sun, Yu; Wen, Li-Li; Yip, Ping-Keung; Chu, Yi-Min; Chen, Yen-Ching

    2015-12-01

    Leisure activities have been associated with a decreased risk of dementia. However, to date, no study has explored how apolipoprotein E (ApoE) e4 status or vascular risk factors modified the association between leisure activities and dementia risks. This case-control study recruited patients (age ≥ 60 years) with Alzheimer's disease (AD; n = 292) and vascular dementia (VaD; n = 144) and healthy controls (n = 506) from three teaching hospitals in Taiwan between 2007 and 2010. Information on patient's leisure activities were obtained through a questionnaire. Conditional logistic regression models were used to assess the association of leisure activities and ApoE e4 status with the risk of dementia. High-frequency physical activity was associated with a decreased risk of AD [adjusted odds ratio (AOR) = 0.45], and the results become more evident among ApoE e4 carriers with AD (AOR = 0.30) and VaD (AOR = 0.26). Similar findings were observed for cognitive (AOR = 0.42) and social activities (AOR = 0.55) for AD. High-frequency physical, cognitive, and social activities were associated with a decreased risk of VaD (AOR = 0.29-0.60). Physical and social activities significantly interacted with each other on the risk of VaD (pinteraction = 0.04). Physical activity consistently protects against AD and VaD. Significant interactions were identified across different types of leisure activities in lowering dementia risk. Copyright © 2014. Published by Elsevier B.V.

  13. Apolipoprotein E and Alzheimer disease: Genotype-specific risks by age and sex

    SciTech Connect

    Bickeboeller, H. |; Babron, M.C.; Clerget-Darpoux, F.

    1997-02-01

    The distribution of apolipoprotein E (APOE) genotypes as a function of age and sex has been examined in a French population of 417 Alzheimer disease (AD) patients and 1,030 control subjects. When compared to the APOE {epsilon}3 allele, an increased risk associated with the APOE {epsilon}4 allele (odds ratio [OR] [{epsilon}4] = 2.7 with 95% confidence interval [CI] = 2.0-3.6; P < .001) and a protective effect of the APOE {epsilon}2 allele (OR[{epsilon}2] = 0.5 with 95% CI = 0.3-0.98; P = .012) were retrieved. An effect of the {epsilon}4 allele dosage on susceptibility was confirmed (OR[{epsilon}4/{epsilon}4] vs. the {epsilon}3/{epsilon}3 genotype = 11.2 [95% CI = 4.0-31.6]; OR[{epsilon}3/{epsilon}4] vs. the {epsilon}3/{epsilon}3 genotype = 2.2 [95% Cl = 1.5-3.5]). The frequency of the {epsilon}4 allele was lower in male cases than in female cases, but, since a similar difference was found in controls, this does not lead to a difference in OR between sex. ORs for the {epsilon}4 allele versus the {epsilon}3 allele, OR({epsilon}4), were not equal in all age classes: OR({epsilon}4) in the extreme groups with onset at < 60 years or > 79 years were significantly lower than those from the age groups 60-79 years. In {epsilon}3/{epsilon}4 individuals, sex-specific lifetime risk estimates by age 85 years (i.e., sex-specific penetrances by age 85 years) were 0.14 (95% CI 0.04-0.30) for men and 0.17 (95% CI 0.09-0.28) for women. 53 refs., 1 fig., 3 tabs.

  14. Health-protective and Adverse Effects of the Apolipoprotein E ε2 Allele in Older Males

    PubMed Central

    Kulminski, Alexander M.; Ukraintseva, Svetlana V.; Arbeev, Konstantin G.; Manton, Kenneth G.; Oshima, Junko; Martin, George M.; Il'yasova, Dora; Yashin, Anatoli I.

    2009-01-01

    OBJECTIVES: To re-examine a health-protective role of the common Apolipoprotein E (APOE) polymorphism focusing on connections between the APOE ε2-containing genotypes and impairments in instrumental activities of daily living [IADL] in older (65+) males and females. To examine how these connections may be mediated by diagnosed coronary heart disease (CHD), Alzheimer's disease, colorectal cancer, macular degeneration (MD), and atherosclerosis. DESIGN: Retrospective cross-sectional study. SETTING: The unique disability-focused data from a genetic sub-sample of the 1999 National Long Term Care Survey linked with Medicare service use files. PARTICIPANTS: 1733 genotyped individuals interviewed on IADL disabilities. MEASUREMENTS: Indicators of IADL impairments, five geriatric disorders, and ε2-containing genotypes. RESULTS: The ε2/3 genotype is a major contributor to adverse associations between the ε2 allele and IADL disability in males [Odds Ratio (OR)=3.09, Confidence Interval (CI)=1.53-6.26)]. It shows, however, significant protective effects for CHD (OR=0.55, CI=0.33-0.92), while CHD is adversely associated with IADL disability (OR=2.18, CI=1.28-3.72). The presence of five diseases does not significantly alter the adverse association between ε2-containing genotypes and disability. Protective effects of the ε2/3 genotype for CHD (OR=0.52, CI=0.27-0.99) and deleterious effects for IADL (OR=3.50, CI=1.71-7.14) for males hold in multivariate models with both these factors included. No significant associations between the ε2-containing genotypes and IADL are found in females. CONCLUSIONS: The ε2 allele can play a dual role in males, protecting them against some health disorders, while promoting others. Strong adverse relationships with disability suggest that ε2-containing genotypes can be unfavorable factors for the health/well-being of aging males. PMID:18179501

  15. Crystal Structure of the Mycoplasma arthritidis-Derived Mitogen in Apo Form Reveals a 3D Domain-Swapped Dimer

    SciTech Connect

    Liu, L.; Li, Z; Guo, Y; VanVranken, S; Mourad, W; Li, H

    2010-01-01

    Mycoplasma arthritidis-derived mitogen (MAM) is a superantigen that can activate large fractions of T cells bearing particular V{beta} elements of T cell receptor. Here, we report the crystal structure of a MAM mutant K201A in apo form (unliganded) at 2.8-{angstrom} resolutions. We also partially refined the crystal structures of the MAM wild type and another MAM mutant L50A in apo forms at low resolutions. Unexpectedly, the structures of these apo MAM molecules display a three-dimensional domain-swapped dimer. The entire C-terminal domains of these MAM molecules are involved in the domain swapping. Functional analyses demonstrated that the K201A and L50A mutants do not show altered ability to bind to their host receptors and that they stimulate the activation of T cells as efficiently as does the wild type. Structural comparisons indicated that the 'reconstituted' MAM monomer from the domain-swapped dimer displays large differences at the hinge regions from the MAM{sub wt} molecule in the receptor-bound form. Further comparison indicated that MAM has a flexible N-terminal loop, implying that conformational changes could occur upon receptor binding.

  16. Evidence for a functional dimeric form of the PcrA helicase in DNA unwinding.

    PubMed

    Yang, Ye; Dou, Shuo-Xing; Ren, Hua; Wang, Peng-Ye; Zhang, Xing-Dong; Qian, Min; Pan, Bing-Yi; Xi, Xu Guang

    2008-04-01

    PcrA helicase, a member of the superfamily 1, is an essential enzyme in many bacteria. The first crystal structures of helicases were obtained with PcrA. Based on structural and biochemical studies, it was proposed and then generally believed that PcrA is a monomeric helicase that unwinds DNA by an inchworm mechanism. But a functional state of PcrA from unwinding kinetics studies has been lacking. In this work, we studied the kinetic mechanism of PcrA-catalysed DNA unwinding with fluorometric stopped-flow method under both single- and multiple-turnover conditions. It was found that the PcrA-catalysed DNA unwinding depended strongly on the PcrA concentration as well as on the 3'-ssDNA tail length of the substrate, indicating that an oligomerization was indispensable for efficient unwinding. Study of the effect of ATP concentration on the unwinding rate gave a Hill coefficient of approximately 2, suggesting strongly that PcrA functions as a dimer. It was further determined that PcrA unwound DNA with a step size of 4 bp and a rate of approximately 9 steps per second. Surprisingly, it was observed that PcrA unwound 12-bp duplex substrates much less efficiently than 16-bp ones, highlighting the importance of protein-DNA duplex interaction in the helicase activity. From the present studies, it is concluded that PcrA is a dimeric helicase with a low processivity in vitro. Implications of the experimental results for the DNA unwinding mechanism of PcrA are discussed.

  17. The structure of apo and holo forms of xylose reductase, a dimeric aldo-keto reductase from Candida tenuis.

    PubMed

    Kavanagh, Kathryn L; Klimacek, Mario; Nidetzky, Bernd; Wilson, David K

    2002-07-16

    Xylose reductase is a homodimeric oxidoreductase dependent on NADPH or NADH and belongs to the largely monomeric aldo-keto reductase superfamily of proteins. It catalyzes the first step in the assimilation of xylose, an aldose found to be a major constituent monosaccharide of renewable plant hemicellulosic material, into yeast metabolic pathways. It does this by reducing open chain xylose to xylitol, which is reoxidized to xylulose by xylitol dehydrogenase and metabolically integrated via the pentose phosphate pathway. No structure has yet been determined for a xylose reductase, a dimeric aldo-keto reductase or a family 2 aldo-keto reductase. The structures of the Candida tenuis xylose reductase apo- and holoenzyme, which crystallize in spacegroup C2 with different unit cells, have been determined to 2.2 A resolution and an R-factor of 17.9 and 20.8%, respectively. Residues responsible for mediating the novel dimeric interface include Asp-178, Arg-181, Lys-202, Phe-206, Trp-313, and Pro-319. Alignments with other superfamily members indicate that these interactions are conserved in other dimeric xylose reductases but not throughout the remainder of the oligomeric aldo-keto reductases, predicting alternate modes of oligomerization for other families. An arrangement of side chains in a catalytic triad shows that Tyr-52 has a conserved function as a general acid. The loop that folds over the NAD(P)H cosubstrate is disordered in the apo form but becomes ordered upon cosubstrate binding. A slow conformational isomerization of this loop probably accounts for the observed rate-limiting step involving release of cosubstrate. Xylose binding (K(m) = 87 mM) is mediated by interactions with a binding pocket that is more polar than a typical aldo-keto reductase. Modeling of xylose into the active site of the holoenzyme using ordered waters as a guide for sugar hydroxyls suggests a convincing mode of substrate binding.

  18. The Association Between Apolipoprotein E and Functional Outcome After Traumatic Brain Injury: A Meta-Analysis.

    PubMed

    Li, Lizhuo; Bao, Yijun; He, Songbai; Wang, Gang; Guan, Yanlei; Ma, Dexuan; Wu, Rile; Wang, Pengfei; Huang, Xiaolong; Tao, Shanwei; Liu, Qiwen; Wang, Yunjie; Yang, Jingyun

    2015-11-01

    Traumatic brain injury (TBI) is a leading cause of death and disability. Previous studies have investigated the association of apolipoprotein E (APOE) ε4 with functional outcome after TBI and reported inconsistent results.The purpose of this study was to perform a systematic literature search and conduct meta-analyses to examine whether APOE ε4 is associated with poorer functional outcome in patients with TBI.We performed a systematic literature search in PubMed, Cochrane Library, Embase, Google Scholar, and HuGE.The eligibility criteria of this study included the following: Patients had TBI; the studies reported APOE genotype data or provided odds ratios (ORs) and the corresponding 95% confidence intervals (CIs); the functional outcome was assessed using the Glasgow Outcome Scale (GOS) or the Glasgow Outcome Scale Extended (GOSE); and patients were followed for at least 3 months after TBI.In all meta-analyses, we used random-effects models to calculate the odds ratio as a measure of association. We examined the association of APOE ε4 with functional outcome at different time points after TBI.A total of 12 studies met the eligibility criteria and were included in the meta-analyses. We did not find a significant association between APOE ε4 and functional outcome at 6 (P = 0.23), 12 (P = 0.44), and 24 months (P = 0.85) after TBI. However, APOE ε4 was associated with an increased risk of unfavorable long-term (≥6 months) functional outcome after TBI (OR = 1.36, 95% CI: 1.07-1.74, P = 0.01).Limitations of this study include The sample size was limited; the initial severity of TBI varied within and across studies; we could not control for potential confounding factors, such as age at injury and sex; a meta-analysis of the genotype dosage effect was not feasible; and we could not examine the association with specific factors such as neurobehavioral or specific cognitive functions.Our meta-analysis indicates APOE ε4 is associated with the long

  19. Aged Garlic Extract Suppresses the Development of Atherosclerosis in Apolipoprotein E-Knockout Mice.

    PubMed

    Morihara, Naoaki; Hino, Atsuko; Yamaguchi, Takako; Suzuki, Jun-Ichiro

    2016-02-01

    Aged garlic extract (AGE) has been shown to retard the progression of coronary calcification in patients with coronary artery disease. To clarify the mechanism of AGE's action to retard atherosclerosis, we investigated whether AGE suppresses the formation and progression of atherosclerosis in Apolipoprotein E (Apoe)-knockout (ApoE-KO) mice. Male C57BL/6J mice (control mice, 5 wk old) were fed a standard diet, whereas male ApoE-KO mice (5 wk old) were fed a standard diet with or without 3% AGE for 12 or 24 wk. After the treatment, blood samples, aortas, and spleens were collected from all mice. Concentrations of total cholesterol (TC), HDL cholesterol, and triglycerides (TGs) in serum were measured. The area of atherosclerotic lesion in the aorta was examined by Oil Red O staining. The relative abundances of monocytes plus macrophages (CD11b(+) cells) and interferon-γ-producing CD4(+) T cells in spleen were assessed by flow cytometric analysis. The atherosclerotic lesion areas in the aortas of ApoE-KO mice were 87 and 114 times as great (P < 0.01) as those in control mice at 12 and 24 wk, respectively. AGE feeding significantly inhibited the progression of atherosclerotic lesion area in ApoE-KO mice by 22% (P < 0.05) at 12 wk. In addition, serum concentrations of TC and TGs in ApoE-KO mice were significantly higher than those in control mice at 12 and 24 wk. Treatment with AGE significantly suppressed the increases in serum concentrations of TC and TGs in ApoE-KO mice by 21% (P < 0.05) and 19% (P < 0.05) at 24 wk, respectively, and reduced the relative abundance of CD11b(+) cells in ApoE-KO mice by 24% (P < 0.05) at 12 wk. These data suggest that the antiatherosclerotic activity of AGE is at least partly due to the suppression of inflammation and lipid deposition in the vessels during the early stage of atherosclerotic development in ApoE-KO mice. © 2016 American Society for Nutrition.

  20. P2Y receptors and atherosclerosis in apolipoprotein E-deficient mice

    PubMed Central

    Guns, Pieter-Jan DF; Hendrickx, Jan; Van Assche, Tim; Fransen, Paul; Bult, Hidde

    2010-01-01

    Background and purpose: P2Y nucleotide receptors are involved in the regulation of vascular tone, smooth muscle cell (SMC) proliferation and inflammatory responses. The present study investigated whether they are involved in atherosclerosis. Experimental approach: mRNA of P2Y receptors was quantified (RT-PCR) in atherosclerotic and plaque-free aorta segments of apolipoprotein E-deficient (apoE–/–) mice. Macrophage activation was assessed in J774 macrophages, and effects of non-selective purinoceptor antagonists on atherosclerosis were evaluated in cholesterol-fed apoE–/– mice. Key results: P2Y6 receptor mRNA was consistently elevated in segments with atherosclerosis, whereas P2Y2 receptor expression remained unchanged. Expression of P2Y1 or P2Y4 receptor mRNA was low or undetectable, and not influenced by atherosclerosis. P2Y6 mRNA expression was higher in cultured J774 macrophages than in cultured aortic SMCs. Furthermore, immunohistochemical staining of plaques demonstrated P2Y6-positive macrophages, but few SMCs, suggesting that macrophage recruitment accounted for the increase in P2Y6 receptor mRNA during atherosclerosis. In contrast to ATP, the P2Y6-selective agonist UDP increased mRNA expression and activity of inducible nitric oxide synthase and interleukin-6 in J774 macrophages; this effect was blocked by suramin (100–300 µM) or pyridoxal-phosphate-6-azophenyl-2′-4′-disulphonic acid (PPADS, 10–30 µM). Finally, 4-week treatment of cholesterol-fed apoE–/– mice with suramin or PPADS (50 and 25 mg·kg−1·day−1 respectively) reduced plaque size, without changing plaque composition (relative SMC and macrophage content) or cell replication. Conclusions and implications: These results suggest involvement of nucleotide receptors, particularly P2Y6 receptors, during atherosclerosis, and warrant further research with selective purinoceptor antagonists or P2Y6 receptor-deficient mice. PMID:20050854

  1. Alanyl-glutamine attenuates 5-fluorouracil-induced intestinal mucositis in apolipoprotein E-deficient mice

    PubMed Central

    Araújo, C.V.; Lazzarotto, C.R.; Aquino, C.C.; Figueiredo, I.L.; Costa, T.B.; de Oliveira Alves, L.A.; Ribeiro, R.A.; Bertolini, L.R.; Lima, A.A.M.; Brito, G.A.C.; Oriá, R.B.

    2015-01-01

    Apolipoprotein E (APOE=gene, apoE=protein) is a known factor regulating the inflammatory response that may have regenerative effects during tissue recovery from injury. We investigated whether apoE deficiency reduces the healing effect of alanyl-glutamine (Ala-Gln) treatment, a recognized gut-trophic nutrient, during tissue recovery after 5-FU-induced intestinal mucositis. APOE-knockout (APOE-/-) and wild-type (APOE+/+) C57BL6J male and female mice (N=86) were given either Ala-Gln (100 mM) or phosphate buffered saline (PBS) by gavage 3 days before and 5 days after a 5-fluorouracil (5-FU) challenge (450 mg/kg, via intraperitoneal injection). Mouse body weight was monitored daily. The 5-FU cytotoxic effect was evaluated by leukometry. Intestinal villus height, villus/crypt ratio, and villin expression were monitored to assess recovery of the intestinal absorptive surface area. Crypt length, mitotic, apoptotic, and necrotic crypt indexes, and quantitative real-time PCR for insulin-like growth factor-1 (IGF-1) and B-cell lymphoma 2 (Bcl-2) intestinal mRNA transcripts were used to evaluate intestinal epithelial cell turnover. 5-FU challenge caused significant weight loss and leukopenia (P<0.001) in both mouse strains, which was not improved by Ala-Gln. Villus blunting, crypt hyperplasia, and reduced villus/crypt ratio (P<0.05) were found in all 5-FU-challenged mice but not in PBS controls. Ala-Gln improved villus/crypt ratio, crypt length and mitotic index in all challenged mice, compared with PBS controls. Ala-Gln improved villus height only in APOE-/- mice. Crypt cell apoptosis and necrotic scores were increased in all mice challenged by 5-FU, compared with untreated controls. Those scores were significantly lower in Ala-Gln-treated APOE+/+ mice than in controls. Bcl-2 and IGF-1 mRNA transcripts were reduced only in the APOE-/--challenged mice. Altogether our findings suggest APOE-independent Ala-Gln regenerative effects after 5-FU challenge. PMID:25945744

  2. [Impact of olmesartan medoxomil on atherosclerosis lesions in apolipoprotein E knockout mice].

    PubMed

    Li, H; Shi, L Y; Chen, L; Lu, Y Z; Yu, B; Qi, G X

    2016-08-16

    To investigate the effect and possible mechanisms of olmesartan medoxomil on atherosclerosis of apolipoprotein E knockout (ApoE(-/-)) mice. Sixteen 6-week-old male ApoE(-/-) mice were randomly divided into atherosclerosis model group fed with high fat diet, and olmesartan medoxomil intervention group fed with high fat diet and olmesartan medoxomil (10 mg·kg(-1)·day(-1,) per gavage). Eight C57BL/6 mice were fed with normal diet, and treated for 12 weeks.The blood pressure and the serum level of lipid were detected; the aorta were removed, oil red staining for plaque area, Hematoxylin and eosin (HE) staining for plaque morphology, Elastica van Gieson (EVG) staining for elastin, and picrosirius red (PSR) for collagen respectively; and the expression of cathepsin S (Cat S), smooth action protein (ASMA) and macrophage surface molecule-3 (Mac-3) were detected by immunohistochemisty analysis. Serum cholesterol and low density lipoprotein levels were significantly higher in atherosclerosis model group than in control group[(15.08±1.64) vs (2.06±0.15) mmol/L, (15.60±1.05) vs (0.00±0.00) mmol/L] (all P<0.01), while triglyceride level was similar between the two group.In contrast to model group, the mice in intervention group showed no statistical difference in blood pressure and plasma lipid levels, while the plaque areas in the aorta were significantly decreased (P<0.05) as well as the expression of Cat S and Mac-3[(2.4±1.2) vs (8.8±3.2)%, (2.2±1.2) vs (7.2±2.8)%] (all P<0.01). In addition, the elastin levels, collagen contents, and the expression of ASMA remained significantly higher compared with model group (P<0.05). Olmesartan medoxomil could slow down the atherosclerosis process, the possible mechanism was implicated with the suppression of Cat S and decreased inflammatory responses alongside the increased elastin and collagen contents.

  3. Sequence Diversity and Large-Scale Typing of SNPs in the Human Apolipoprotein E Gene

    PubMed Central

    Nickerson, Deborah A.; Taylor, Scott L.; Fullerton, Stephanie M.; Weiss, Kenneth M.; Clark, Andrew G.; Stengård, Jari H.; Salomaa, Veikko; Boerwinkle, Eric; Sing, Charles F.

    2000-01-01

    A common strategy for genotyping large samples begins with the characterization of human single nucleotide polymorphisms (SNPs) by sequencing candidate regions in a small sample for SNP discovery. This is usually followed by typing in a large sample those sites observed to vary in a smaller sample. We present results from a systematic investigation of variation at the human apolipoprotein E locus (APOE), as well as the evaluation of the two-tiered sampling strategy based on these data. We sequenced 5.5 kb spanning the entire APOE genomic region in a core sample of 72 individuals, including 24 each of African-Americans from Jackson, Mississippi; European-Americans from Rochester, Minnesota; and Europeans from North Karelia, Finland. This sequence survey detected 21 SNPs and 1 multiallelic indel, 14 of which had not been previously reported. Alleles varied in relative frequency among the populations, and 10 sites were polymorphic in only a single population sample. Oligonucleotide ligation assays (OLA) were developed for 20 of these sites (omitting the indel and a closely-linked SNP). These were then scored in 2179 individuals sampled from the same three populations (n = 843, 884, and 452, respectively). Relative allele frequencies were generally consistent with estimates from the core sample, although variation was found in some populations in the larger sample at SNPs that were monomorphic in the corresponding smaller core sample. Site variation in the larger samples showed no systematic deviation from Hardy-Weinberg expectation. The large OLA sample clearly showed that variation in many, but not all, of OLA-typed SNPs is significantly correlated with the classical protein-coding variants, implying that there may be important substructure within the classical ɛ2, ɛ3, and ɛ4 alleles. Comparison of the levels and patterns of polymorphism in the core samples with those estimated for the OLA-typed samples shows how nucleotide diversity is underestimated when

  4. The positive relationship of serum paraoxonase-1 activity with apolipoprotein E is abrogated in metabolic syndrome.

    PubMed

    Dullaart, Robin P F; Kwakernaak, Arjan J; Dallinga-Thie, Geesje M

    2013-09-01

    High density lipoproteins (HDL) contain paraoxonase-1 (PON-1), which has strong anti-oxidative properties. Apolipoprotein E (apoE) may enhance PON-1 activity in vitro, but the extent to which PON-1 activity is determined by circulating apoE levels is unknown. Here we determined relationships of serum PON-1 activity with apoE in subjects without and with metabolic syndrome (MetS). We measured PON-1 activity (arylesterase activity), plasma apoE and serum amyloid A (SAA) in 93 subjects without and in 75 subjects with MetS (25 and 54 subjects with Type 2 diabetes mellitus (T2DM), respectively; p < 0.001). PON-1 activity was lower in MetS (p < 0.005) coinciding lower HDL cholesterol, apoA-I (p < 0.001)) and SAA levels (p < 0.01), whereas apoE was increased in relation to higher triglycerides (p < 0.01). In subjects without MetS, PON-1 activity was correlated positively with apoE (r = 0.376, p < 0.001), but this relationship was absent in MetS subjects (r = 0.085, p = 0.47). Multiple linear regression analysis showed that the relationship of PON-1 activity with apoE was different in subjects with MetS compared to subjects without MetS (β = -0.270, p = 0.014 for the interaction between apoE and MetS), independently from age, sex, T2DM, use of glucose lowering drugs, anti-hypertensives and the inverse relation with SAA levels (p = 0.008). Of the individual MetS components, apoE only interacted with low HDL-C on PON-1 activity (β = -0.175, p = 0.074). The relationship of apoE with PON-1 activity was neither modified by T2DM (p = 0.49), nor by SAA (p = 0.79). Higher apoE levels may confer higher PON-1 activity. The relationship of PON-I activity with total plasma apoE is apparently abrogated in MetS. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  5. Identification of a Chrysanthemic Ester as an Apolipoprotein E Inducer in Astrocytes

    PubMed Central

    Zhao, Wenchen; Shimizu, Yoko; Pfeifer, Tom A.; Tak, Jun-Hyung; Isman, Murray B.; Van den Hoven, Bernard; Duggan, Mark E.; Wood, Michael W.; Wellington, Cheryl L.

    2016-01-01

    The apolipoprotein E (APOE) gene is the most highly associated susceptibility locus for late onset Alzheimer’s Disease (AD), and augmenting the beneficial physiological functions of apoE is a proposed therapeutic strategy. In a high throughput phenotypic screen for small molecules that enhance apoE secretion from human CCF-STTG1 astrocytoma cells, we show the chrysanthemic ester 82879 robustly increases expressed apoE up to 9.4-fold and secreted apoE up to 6-fold and is associated with increased total cholesterol in conditioned media. Compound 82879 is unique as structural analogues, including pyrethroid esters, show no effect on apoE expression or secretion. 82879 also stimulates liver x receptor (LXR) target genes including ATP binding cassette A1 (ABCA1), LXRα and inducible degrader of low density lipoprotein receptor (IDOL) at both mRNA and protein levels. In particular, the lipid transporter ABCA1 was increased by up to 10.6-fold upon 82879 treatment. The findings from CCF-STTG1 cells were confirmed in primary human astrocytes from three donors, where increased apoE and ABCA1 was observed along with elevated secretion of high-density lipoprotein (HDL)-like apoE particles. Nuclear receptor transactivation assays revealed modest direct LXR agonism by compound 82879, yet 10 μM of 82879 significantly upregulated apoE mRNA in mouse embryonic fibroblasts (MEFs) depleted of both LXRα and LXRβ, demonstrating that 82879 can also induce apoE expression independent of LXR transactivation. By contrast, deletion of LXRs in MEFs completely blocked mRNA changes in ABCA1 even at 10 μM of 82879, indicating the ability of 82879 to stimulate ABCA1 expression is entirely dependent on LXR transactivation. Taken together, compound 82879 is a novel chrysanthemic ester capable of modulating apoE secretion as well as apoE-associated lipid metabolic pathways in astrocytes, which is structurally and mechanistically distinct from known LXR agonists. PMID:27598782

  6. Apolipoprotein E genotyping and cerebrospinal fluid tau protein: implications for the clinical diagnosis of Alzheimer's disease.

    PubMed

    Arai, H; Higuchi, S; Sasaki, H

    1997-01-01

    Apolipoprotein E (ApoE) genotyping was conducted in sporadic Alzheimer's disease (AD, n = 91) as well as in other dementing disorders including Parkinson's disease (PD, n = 73), autopsy-confirmed diffuse Lewy body disease (DLBD, n = 16), progressive supranuclear palsy (n = 13), vascular dementia (n = 55), alcoholic dementia (n =25) and normal control subjects (n = 77). ApoE epsilon 4 allele frequency was significantly higher in AD (33.5%, p < 0.001), DLBD (40.6%, p < 0.001) and demented PD (29.4%, p < 0.05) compared to that in normal controls (11.7%). The association of the ApoE epsilon 4 allele with AD was more pronounced in early-onset AD (46.4%) than in late-onset AD (27.8%). 46% of the AD individuals developed AD without association to ApoE epsilon 4, and epsilon 4 homozygotes were found not only in AD, but also in many of other dementing disorders. These results suggest that ApoE genotyping cannot provide certainty about the presence of absence of AD, and that it should be used as an adjunct to other diagnostic tests for AD. On the other hand, cerebrospinal fluid (CSF) tau levels were significantly elevated (p < 0.0001) in AD (78.0 +/- 44.2 pg/ml) compared to those in normal controls (10.6 +/- 8.6 pg/ml). The specificity and the sensitivity of distinguishing AD from normal controls was 95.0 and 91.2%, respectively. Elevated CSF-tau levels were also detected in some patients with acute neurological diseases including meningoencephalitis, Creutzfeld-Jacob disease, normal pressure hydrocephalus and vitamin B12 deficiency encephalopathy. Increased CSF-tau levels in AD were found regardless of the age at onset, clinical stage, ApoE genotype, alpha 1-antichymotrypsin genotype, and presenilin-1 genotype. The CSF-tau levels continued to be abnormal during the progression of AD. These results suggest that CSF-tau serves as an unequivocal and reliable biological marker to aid in the clinical diagnosis of AD.

  7. [Is there an interaction between sleep-disordered breathing, depression and apolipoprotein E phenotype?].

    PubMed

    Lemoine, P; Sassolas, A; Lestra, C; Laforest, L; Chamba, G

    2004-01-01

    Sleep-disordered breathing (SDB) is widely underdiagnosed among adults. However, SDB may be considered as a public health problem because of clinical consequences for the patient: impaired awake performance, increased risk factor for cardiovascular diseases and increased prevalence of depression. Apolipoprotein E (apoE), a protein involved in lipid metabolism, has 3 major alleles e2, e3 and e4. Recently, it has been shown that apoE e4 allele, a well-known risk factor for cardiovascular diseases, was also associated with SDB. In this study, we assessed a potential interaction between SDB, depression and apoE phenotype. 92 male patients (36-79 years old, mean age 58.0 11.2) consulting in hospital for SDB were enrolled in the study. Each patient had the following exams: 1) overnight polysomnography to determine apnea/hypopnea index (AHI=average number of respiratory events 10 seconds with no breathing per hour). A moderate-to-severe SDB was defined with AHI 15. 2) a psychiatric examination to look for previous or present symptoms of depressive illness. 3) blood sampling to determine apoE genotype (using PCR-RFLP method). In our study, allele frequencies for apoE e2, e3 and e4 were similar to those reported in general population. Among 92 patients, 68 (74%) presented moderate-to-severe SDB and 28 (30%) previous or present symptoms of depressive illness. Our results indicate that: 1) apoE e4 was significantly associated with moderate-to-severe SDB (n=92, p=0.03), 2) scores of apnea-hypopnea index were significantly higher in e4-positive versus e4-negative participants (n=57, p=0,05) and 3) ApoE and depression were not linked. This study confirms a potential interaction between SDB and apoE phenotype, as recently reported. This suggests that e4 allele might be a genetic risk factor for SDB (e4 allele frequency higher in patients with moderate-to-severe SDB versus general population) and/or consequently a deleterious factor for this pathology (increased AHI in e4-positive

  8. Human plasma lipid modulation in schistosomiasis mansoni depends on apolipoprotein E polymorphism.

    PubMed

    Martins da Fonseca, Caíque Silveira; Pimenta Filho, Adenor Almeida; dos Santos, Bianka Santana; da Silva, César Augusto; Domingues, Ana Lúcia Coutinho; Owen, James Stuart; Lima, Vera Lúcia de Menezes

    2014-01-01

    Schistosomiasis mansoni is a parasitic liver disease, which causes several metabolic disturbances. Here, we evaluate the influence of Apolipoprotein E (APOE) gene polymorphism, a known modulator of lipid metabolism, on plasma lipid levels in patients with hepatosplenic schistosomiasis. Blood samples were used for APOE genotyping and to measure total cholesterol (TC), LDL-C, HDL-C and triglycerides. Schistosomiasis patients had reduced TC, LDL-C and triglycerides (25%, 38% and 32% lower, respectively; P<0.0001) compared to control individuals, whereas HDL-C was increased (10% higher; P = 0.0136). Frequency of the common alleles, ε2, ε3 and ε4, was similar (P = 0.3568) between controls (n = 108) and patients (n = 84), implying that APOE genotype did not affect susceptibility to the advanced stage of schistosomiasis. Nevertheless, while patient TC and LDL-C levels were significantly reduced for each allele (except TC in ε2 patients), changes in HDL-C and triglycerides were noted only for the less common ε2 and ε4 alleles. The most striking finding, however, was that accepted regulation of plasma lipid levels by APOE genotype was disrupted by schistosomiasis. Thus, while ε2 controls had higher TC and LDL-C than ε3 carriers, these parameters were lower in ε2 versus ε3 patients. Similarly, the inverse relationship of TG levels in controls (ε2>ε3>ε4) was absent in patients (ε2 or ε4>ε3), and the increase in HDL-C of ε2 or ε4 patients compared to ε3 patients was not seen in the control groups. We confirm that human schistosomiasis causes dyslipidemia and report for the first time that certain changes in plasma lipid and lipoprotein levels depend on APOE gene polymorphism. Importantly, we also concluded that S. mansoni disrupts the expected regulation of plasma lipids by the different ApoE isoforms. This finding suggests ways to identify new metabolic pathways affected by schistosomiasis and also potential molecular targets to treat

  9. Apolipoprotein E genotype and the diagnostic accuracy of cerebrospinal fluid biomarkers for Alzheimer disease.

    PubMed

    Lautner, Ronald; Palmqvist, Sebastian; Mattsson, Niklas; Andreasson, Ulf; Wallin, Anders; Pålsson, Erik; Jakobsson, Joel; Herukka, Sanna-Kaisa; Owenius, Rikard; Olsson, Bob; Hampel, Harald; Rujescu, Dan; Ewers, Michael; Landén, Mikael; Minthon, Lennart; Blennow, Kaj; Zetterberg, Henrik; Hansson, Oskar

    2014-10-01

    Several studies suggest that the apolipoprotein E (APOE) ε4 allele modulates cerebrospinal fluid (CSF) levels of β-amyloid 42 (Aβ42). Whether this effect is secondary to the association of the APOE ε4 allele with cortical Aβ deposition or whether APOE ε4 directly influences CSF levels of Aβ42 independently of Aβ pathology remains unknown. To evaluate whether the APOE genotype affects the diagnostic accuracy of CSF biomarkers for Alzheimer disease (AD), in particular Aβ42 levels, and whether the association of APOE ε4 with CSF biomarkers depends on cortical Aβ status. We collected data from 4 different centers in Sweden, Finland, and Germany. Cohort A consisted of 1345 individuals aged 23 to 99 years with baseline CSF samples, including 309 with AD, 287 with prodromal AD, 399 with stable mild cognitive impairment, 99 with dementias other than AD, and 251 controls. Cohort B included 105 nondemented younger individuals (aged 20-34 years) with CSF samples available. Cohort C included 118 patients aged 60 to 80 years with mild cognitive symptoms who underwent flutemetamol F 18 ([18F]flumetamol) positron emission tomography amyloid imaging and CSF tap. Standard care. Cerebrospinal fluid levels of Aβ42 and total and phosphorylated tau in relation to the APOE ε2/ε3/ε4 polymorphism in different diagnostic groups and in cases with or without cortical uptake of [18F]flutemetamol. The CSF levels of Aβ42 but not total and phosphorylated tau were lower in APOE ε4 carriers compared with noncarriers irrespective of diagnostic group (cohort A). Despite this, CSF levels of Aβ42 differed between participants with AD when compared with controls and those with stable mild cognitive impairment, even when stratifying for APOE genotype (P < .001 to P = .006). Multiple binary logistic regression revealed that CSF levels of Aβ42 and APOE ε4 genotype were independent predictors of AD diagnosis. In cohort B, APOE ε4 carrier status did not influence CSF levels of

  10. Sirt1 is involved in decreased bone formation in aged apolipoprotein E-deficient mice

    PubMed Central

    Hong, Wei; Xu, Xiao-ya; Qiu, Zhao-hui; Gao, Jian-jun; Wei, Zhan-ying; Zhen, Li; Zhang, Xiao-li; Ye, Zhi-bing

    2015-01-01

    Aim: Apolipoprotein E (ApoE) plays an important role in the transport and metabolism of lipids. Recent studies show that bone mass is increased in young apoE−/− mice. In this study we investigated the bone phenotype and metabolism in aged apoE−/− mice. Methods: Femurs and tibias were collected from 18- and 72-week-old apoE−/− mice and their age-matched wild-type (WT) littermates, and examined using micro-CT and histological analysis. Serum levels of total cholesterol, oxidized low-density lipoprotein (ox-LDL) and bone turnover markers were measured. Cultured bone mesenchymal stem cells (BMSCs) from tibias and femurs of 18-week-old apoE−/− mice were used in experiments in vitro. The expression levels of Sirt1 and Runx2 in bone tissue and BMSCs were measured using RT-PCR and Western blot analysis. Results: Compared with age-matched WT littermates, young apoE−/− mice exhibited high bone mass with increased bone formation, accompanied by higher serum levels of bone turnover markers OCN and TRAP5b, and higher expression levels of Sirt1, Runx2, ALP and OCN in bone tissue. In contrast, aged apoE−/− mice showed reduced bone formation and lower bone mass relative to age-matched WT mice, accompanied by lower serum OCN levels, and markedly reduced expression levels of Sirt1, Runx2, ALP and OCN in bone tissue. After BMSCs were exposed to ox-LDL (20 μg/mL), the expression of Sirt1 and Runx2 proteins was significantly increased at 12 h, and then decreased at 72 h. Treatment with the Sirt1 inhibitor EX527 (10 μmol/L) suppressed the expression of Runx2, ALP and OCN in BMSCs. Conclusion: In contrast to young apoE−/− mice, aged apoE−/− mice showe lower bone mass than age-matched WT mice. Long-lasting exposure to ox-LDL decreases the expression of Sirt1 and Runx2 in BMSCs, which may explain the decreased bone formation in aged apoE−/− mice. PMID:26592520

  11. Serum apolipoprotein E is associated with long-term risk of Alzheimer's disease: The Rotterdam Study.

    PubMed

    Wolters, Frank J; Koudstaal, Peter J; Hofman, Albert; van Duijn, Cornelia M; Ikram, M Arfan

    2016-03-23

    Serum levels of apolipoprotein E (apoE) have been suggested as potential biomarker for dementia, but the long-term association between apoE and risk of dementia is uncertain. Between 1990 and 1993, we measured serum apoE by immunoassay in 1042 non-demented individuals (mean ± SD age 68.4 ± 7.3 years; 59.3% women) from the population-based Rotterdam Study. Follow-up for dementia was complete until 2014. We used Cox models to determine the risk of dementia and Alzheimer's disease in relation to apoE, adjusting for age, sex, educational level, cardiovascular risk factors, and additionally APOE genotype. Serum apoE was associated to APOE genotype (p-trend=1.0E-51, r(2)=0.21). In men, apoE tended to be lower with age, whereas in women the opposite was observed (p-trend=0.07 and 0.08, respectively). During a median follow-up of 15.7 years (IQR 9.7-21.7), 220 participants developed dementia, of whom 180 had Alzheimer's disease. Lower serum apoE was associated with an increased risk of dementia (HR, 95%CI, per SD decrease: 1.25, 1.05-1.48) and in particular Alzheimer's disease (1.51, 1.23-1.86), which remained statistically significant for Alzheimer's disease after additionally adjusting for APOE genotype (1.28, 1.01-1.62). When stratifying analyses in 5-year time frames, risk estimates were similar throughout the study period. Serum apoE tended to marginally improve 20-year prediction of Alzheimer's disease (IDI 0.008, 95%CI -0.001-0.026, p=0.086), but not all dementia. Serum apoE is associated with long-term risk of Alzheimer's disease in the general population, independent of APOE genotype. Additional predictive value of serum apoE was limited. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  12. Assembly of Acanthamoeba myosin-II minifilaments. Definition of C-terminal residues required to form coiled-coils, dimers, and octamers.

    PubMed

    Turbedsky, Kirsi; Pollard, Thomas D

    2005-01-14

    Acanthamoeba myosin-II forms bipolar octamers by three successive steps of dimerization of the C-terminal, coiled-coil tail. In this study, we generated N-terminal and C-terminal truncation constructs and point mutants of the Acanthamoeba myosin-II tail to delineate the structural requirements for assembly of bipolar mini-filaments. By the use of light-scattering, CD spectroscopy, analytical ultracentrifugation, and tryptophan fluorescence experiments, we determined that: (1) the C-terminal 14 heptad repeats plus most of the tailpiece (residues 1381-1509) are required to form antiparallel dimers of coiled-coils; (2) amino acid residues within heptads 23-32 (residues 1254-1325) are required to form tetramers; (3) the C-terminal 32 heptad repeats suffice to assemble octameric minifilaments; (4) A1378 is outside of the interaction interface; (5) the mutation L1475W inhibits dimerization; and (6) F1443 is involved in the dimerization interface but is exposed to the solvent. We propose that the tailpiece (residues 1483-1509) interacts with two heptads (13 and 14, residues 1381-1393), which are important for dimerization and coiled-coil formation. These results support a model in which hydrophobic as well as electrostatic interactions control the register between myosin-II coiled-coils and guide sequential steps of dimerization that generate stable, octameric mini-filaments.

  13. The carp muscle-specific sub-isoenzymes of creatine kinase form distinct dimers at different temperatures.

    PubMed Central

    Sun, Hsi-Wen; Liu, Cheng-Wen; Hui, Cho-Fat; Wu, Jen-Leih

    2002-01-01

    We have previously cloned three muscle-specific sub-isoforms of creatine kinase (CK, EC 2.7.3.2) from the common carp ( Cyprinus carpio ), designated M1-CK, M2-CK, and M3-CK. The enzyme has a key role in maintaining the energy homoeostasis of cells with fluctuating energy requirements. In the present paper, we report that all three M-CKs in the red and white muscle of different temperature-acclimatized carp were ubiquitously distributed in the cytosol and along membranes. In addition, the expression levels of these isoforms were not significantly altered in response to the temperature acclimatization. Interestingly, our studies showed that the formation of distinct homo- or heterodimers among these three M-CKs was found at various temperatures. At higher temperature, the M1M1-CK and M2M2-CK homodimers, and the M1M3-CK heterodimer are the predominant MM-CKs, whereas the M3M3-CK achieves its homodimeric state at lower temperature. We postulated testable homology models to investigate the chemical properties of these dimeric interfaces. M1M1-CK was used as a reference to compare the structural differences with the M3M3-CK dimer. The calculated solvent accessible surface area that was buried in the contact interfaces of the M1M1-CK and M3M3-CK dimers showed an overall decrease of 12% in the M3M3-CK interface. The modelling analysis also suggested a net decrease of twelve hydrophobic residues and a Phe(3)-->Lys substitution in the M3M3-CK interface. An increase in thermolability of the M3M3-CK homodimer might be due to the decrease in subunit ion pairs and buried surface area in this dimer. Based on our findings, we propose that the carp-muscle-specific CK isoenzymes could undergo shuffling to form distinct M-CK homo- or heterodimers in acclimatization to environmental temperatures. PMID:12213085

  14. Systemic markers of the redox balance and apolipoprotein E polymorphism in atherosclerosis: the relevance for an integrated study.

    PubMed

    Lopes, Paula A; Napoleão, Patrícia; Pinheiro, Teresa; Ceia, Fátima; Steghens, Jean-Paul; Pavão, M Leoner; Santos, M Cristina; Viegas-Crespo, Ana M

    2006-07-01

    Prospective studies have demonstrated that an imbalance between oxidative damage and antioxidative protection can play a role in the development and progression of atherosclerosis. Also, genotypes with the apolipoprotein E epsilon4 allele have been associated with an increase risk for this pathology. Based on this knowledge, the aim of this study was to evaluate indicators of the redox balance, trace elements, and apolipoprotein E allelic profile in subjects from the Lisbon population with clinically stable atherosclerosis, at risk for atherosclerotic events, and in healthy subjects for comparison. The activities of superoxide dismutase in erythrocytes and glutathione peroxidase in whole blood, plasma total thiols, and serum ceruloplasmin were kept unchanged among the three groups. Serum alpha- tocopherol was increased in atherosclerotic patients. Total malondialdehyde in serum and protein carbonyls in plasma, which are indicators of lipid and protein oxidative damage, respectively, reached their highest values in risk subjects. The concentrations of potassium and calcium, in plasma and in blood cells, were slightly elevated in patients and might reflect an electrolytic imbalance. Regarding the apolipoprotein E polymorphism, atherosclerotic patients had an increased incidence of the high-risk genotypes for atherogenesis (epsilon3/epsilon4 and epsilon4/epsilon4). A multivariate model applied to the general population using most of the parameters clearly separated the three groups at study (i.e., the healthy group from the steady-state group of risk disease and from the atherosclerotic one). As shown by us, the usefulness of biochemical and complementary genetic markers is warranted for a better knowledge on atherosclerosis molecular basis.

  15. Terpenylic and Related Lactone-Containing Acids: Novel Monoterpene Secondary Organic Aerosol Tracers with Dimer-Forming Properties

    NASA Astrophysics Data System (ADS)

    Claeys, M.; Iinuma, Y.; Szmigielski, R.; Farhat, Y.; Surratt, J. D.; Blockhuys, F.; van Alsenoy, C.; Böge, O.; Sierau, B.; Gómez-González, Y.; Vermeylen, R.; van der Veken, P.; Shahgholi, M.; Chan, A. W.; Herrmann, H.; Seinfeld, J.; Maenhaut, W.

    2009-12-01

    Blue haze is a natural phenomenon that is observed in forested regions worldwide and is due to the formation of secondary organic aerosol (SOA) particles. While evidence exists for organic molecular clusters in the size range of < 2 nm, the chemical structures of the nucleating particles have remained unresolved. In the present study, novel SOA products from the monoterpene α-pinene with unique dimer-forming properties have been identified as lactone-containing terpenoic acids, i.e., terpenylic (molecular weight (MW) 172), terebic (MW 158) and 2-hydroxyterpenylic acid (MW 188), and diaterpenylic acid acetate (MW 232). The structural characterizations were based on synthesis of reference compounds and detailed interpretation of negative ion electrospray ionization mass spectral [(-)ESI-MS] data, including accurate mass and MSn ion trap measurements. Terpenylic acid and diaterpenylic acid acetate are early oxidation products formed upon both photooxidation and ozonolysis, and are abundant SOA tracers in ambient fine aerosol from coniferous forest sites (e.g., K-puszta, Hungary). Terebic and 2-hydroxyterpenylic acid can be explained by further oxidation of terpenylic acid, and are also prominent tracers in ambient fine aerosol. Quantum chemical calculations support that non-covalent dimer formation involving double hydrogen bonding interactions between carboxyl groups of the monomers is energetically favorable. Lactone-containing terpenoic acids also form through photooxidation from monoterpenes other than α-pinene, i.e., terebic acid from Δ3-carene, and terpenylic, homoterpenylic (MW 186), and terebic acid from β-pinene. A distinct feature of terpenylic acid and related lactone-containing acids is that they can be selectively detected in positive ion (+)ESI-MS, unlike isobaric dicarboxylic terpenoic acids such as norpinic (MW 172) and pinic acid (MW 186). Interestingly, terpenylic, terebic and homoterpenylic acid were already reported in the early German

  16. [Investigation of neuroprotective activity of apolipoprotein E peptide mimetic Cog1410 in transgenic lines of Drosophila melanogaster].

    PubMed

    Latypova, E M; Timoshenko, S I; Kislik, G A; Vitek, M; Shvartsman, A L; Sarantseva, S V

    2014-01-01

    The neuroprotective activity of apolipoprotein E (apoE) peptide mimetic Cog1410, containing amino acid sequence of the receptor-binding domain apoE, has been investigated in transgenic lines of Drosophila melanogaster expressing human APP and beta-secretase. Expression of two transgenes caused neuropathological processes attributed to Alzheimer's disease: neurodegeneration, cognitive abnormality and amyloid deposits formation in brain. It was shown that Cog 1410 reduces neurodegeneration in brain of transgenic flies and improves cognitive functions (odor recognition). These data suggest that Cog1410 is a potential neuroprotector that can be used in AD treatment.

  17. The dimeric form of HLA-G molecule is associated with the response of early rheumatoid arthritis (ERA) patients to methotrexate.

    PubMed

    Rizzo, Roberta; Farina, Ilaria; Bortolotti, Daria; Galuppi, Elisa; Padovan, Melissa; Di Luca, Dario; Govoni, Marcello

    2017-03-01

    A growing body of evidence indicates a possible involvement of HLA (human leukocyte antigen)-G antigens in rheumatoid arthritis (RA), mainly in the HLA-G dimeric isoform, the most active HLA-G form with the strongest immunosuppression, that showed an excellent anti-inflammatory effect in collagen-induced arthritis model mice. However, the relevance of HLA-G dimers in RA response to methotrexate (MTX) treatment is still unknown. We analyzed the HLA-G dimers' amount in plasma samples from early rheumatoid arthritis (ERA) patients before MTX therapy and evaluated the role of these molecules as biomarker of the different response to the treatment. Plasma sHLA-G levels were detected by ELISA, and HLA-G dimeric and monomeric forms were revealed by Western blot in 12 MTX responder (reaching DAS28 remission <2.6) and 8 MTX non-responder (DAS28 ≥5.1) patients before the therapy. The response to MTX was evaluated after 6 months of treatment. All ERA patients reaching remission showed higher plasma sHLA-G levels and the 78 kDa HLA-G dimeric form. Unresponsive ERA patients were characterized by lower plasma sHLA-G levels, and only one patient presented the 78 kDa HLA-G dimeric form (DAS28 5.1). Our preliminary results support the hypothesis that in ERA patients, sHLA-G and, in particular, the presence of the dimeric form in plasma samples before MTX therapy could be an a priori biomarker for the response to MTX treatment.

  18. Bax monomers form dimer units in the membrane that further self-assemble into multiple oligomeric species

    NASA Astrophysics Data System (ADS)

    Subburaj, Yamunadevi; Cosentino, Katia; Axmann, Markus; Pedrueza-Villalmanzo, Esteban; Hermann, Eduard; Bleicken, Stephanie; Spatz, Joachim; García-Sáez, Ana J.

    2015-08-01

    Bax is a key regulator of apoptosis that mediates the release of cytochrome c to the cytosol via oligomerization in the outer mitochondrial membrane before pore formation. However, the molecular mechanism of Bax assembly and regulation by other Bcl-2 members remains obscure. Here, by analysing the stoichiometry of Bax oligomers at the single-molecule level, we find that Bax binds to the membrane in a monomeric state and then self-assembles in <1 min. Strikingly, active Bax does not exist in a unique oligomeric state, but as several different species based on dimer units. Moreover, we show that cBid activates Bax without affecting its assembly, while Bcl-xL induces the dissociation of Bax oligomers. On the basis of our experimental data and theoretical modelling, we propose a new mechanism for the molecular pathway of Bax assembly to form the apoptotic pore.

  19. Bax monomers form dimer units in the membrane that further self-assemble into multiple oligomeric species.

    PubMed

    Subburaj, Yamunadevi; Cosentino, Katia; Axmann, Markus; Pedrueza-Villalmanzo, Esteban; Hermann, Eduard; Bleicken, Stephanie; Spatz, Joachim; García-Sáez, Ana J

    2015-08-14

    Bax is a key regulator of apoptosis that mediates the release of cytochrome c to the cytosol via oligomerization in the outer mitochondrial membrane before pore formation. However, the molecular mechanism of Bax assembly and regulation by other Bcl-2 members remains obscure. Here, by analysing the stoichiometry of Bax oligomers at the single-molecule level, we find that Bax binds to the membrane in a monomeric state and then self-assembles in <1 min. Strikingly, active Bax does not exist in a unique oligomeric state, but as several different species based on dimer units. Moreover, we show that cBid activates Bax without affecting its assembly, while Bcl-xL induces the dissociation of Bax oligomers. On the basis of our experimental data and theoretical modelling, we propose a new mechanism for the molecular pathway of Bax assembly to form the apoptotic pore.

  20. Intrapolypeptide interactions between the GTPase effector domain (GED) and the GTPase domain form the bundle signaling element in dynamin dimers.

    PubMed

    Srinivasan, Saipraveen; Mattila, Juha-Pekka; Schmid, Sandra L

    2014-09-16

    Biochemical and structural studies of dynamin have shown that the C-terminus of the GTPase effector domain (GED) folds back and docks onto a platform created by the N- and C-terminal α-helices of the GTPase domain to form a three-helix bundle. While cross-linking studies suggested that insect cell-expressed dynamin existed as a domain-swapped dimer, X-ray structures of protein expressed in Escherichia coli failed to detect evidence of this domain swap. Here, by cross-linking several cysteine pair replacements and analyzing cross-linked species by matrix-assisted laser desorption ionization Mega time of flight, we conclude that dynamin is not domain-swapped and that GED-GTPase domain interactions occur in cis.

  1. Intrapolypeptide Interactions between the GTPase Effector Domain (GED) and the GTPase Domain Form the Bundle Signaling Element in Dynamin Dimers

    PubMed Central

    2015-01-01

    Biochemical and structural studies of dynamin have shown that the C-terminus of the GTPase effector domain (GED) folds back and docks onto a platform created by the N- and C-terminal α-helices of the GTPase domain to form a three-helix bundle. While cross-linking studies suggested that insect cell-expressed dynamin existed as a domain-swapped dimer, X-ray structures of protein expressed in Escherichia coli failed to detect evidence of this domain swap. Here, by cross-linking several cysteine pair replacements and analyzing cross-linked species by matrix-assisted laser desorption ionization Mega time of flight, we conclude that dynamin is not domain-swapped and that GED–GTPase domain interactions occur in cis. PMID:25171143

  2. Anthranilate phosphoribosyltransferase from the hyperthermophilic archaeon Thermococcus kodakarensis shows maximum activity with zinc and forms a unique dimeric structure.

    PubMed

    Perveen, Sumera; Rashid, Naeem; Tang, Xiao-Feng; Imanaka, Tadayuki; Papageorgiou, Anastassios C

    2017-08-01

    Anthranilate phosphoribosyltransferase (TrpD) is involved in tryptophan biosynthesis, catalyzing the transfer of a phosphoribosyl group to anthranilate, leading to the generation of phosphoribosyl anthranilate. TrpD belongs to the phosphoribosyltransferase (PRT) superfamily and is the only member of the structural class IV. X-ray structures of TrpD from seven species have been solved to date. Here, functional and structural characterization of a recombinant TrpD from hyperthermophilic archaeon Thermococcus kodakarensis KOD1 (TkTrpD) was carried out. Contrary to previously characterized Mg(2+)-dependent TrpD enzymes, TkTrpD was found to have a unique divalent cation dependency characterized by maximum activity in the presence of Zn(2+) (1580 μmol·min(-1)·mg(-1), the highest reported for any TrpD) followed by Ca(2+) (948 μmol·min(-1)·mg(-1)) and Mg(2+) (711 μmol·min(-1)·mg(-1)). TkTrpD displayed an unusually low thermostability compared to other previously characterized proteins from T. kodakarensis KOD1. The crystal structure of TkTrpD was determined in free form and in the presence of Zn(2+) to 1.9 and 2.4 Å resolutions, respectively. TkTrpD structure displayed the typical PRT fold similar to other class IV PRTs, with a small N-terminal α-helical domain and a larger C-terminal α/β domain. Electron densities for Zn(2+) were identified at the expected zinc-binding motif, DE(217-218), of the enzyme in each subunit of the dimer. Two additional Zn(2+) were found at a new dimer interface formed in the presence of Zn(2+). A fifth Zn(2+) was found bound to Glu118 at crystal lattice contacts and a sixth one was ligated with Glu235. Based on the TkTrpD-Zn(2+) structure, it is suggested that the formation of a new dimer may be responsible for the higher enzyme activity of TkTrpD in the presence of Zn(2+) ions.

  3. Preliminary crystallographic analysis of a double mutant of the acetyl xylo-oligosaccharide esterase Axe2 in its dimeric form.

    PubMed

    Lansky, Shifra; Alalouf, Onit; Salama, Rachel; Dvir, Hay; Shoham, Yuval; Shoham, Gil

    2014-04-01

    Xylans are polymeric sugars constituting a significant part of the plant cell wall. They are usually substituted with acetyl side groups attached at positions 2 or 3 of the xylose backbone units. Acetylxylan esterases are part of the hemicellulolytic system of many microorganisms which utilize plant biomass for growth. These enzymes hydrolyze the ester linkages of the xylan acetyl groups and thus improve the accessibility of main-chain-hydrolyzing enzymes and their ability to break down the sugar backbone units. The acetylxylan esterases are therefore critically important for those microorganisms and as such could be used for a wide range of biotechnological applications. The structure of an acetylxylan esterase (Axe2) isolated from the thermophilic bacterium Geobacillus stearothermophilus T6 has been determined, and it has been demonstrated that the wild-type enzyme is present as a unique torus-shaped octamer in the crystal and in solution. In order to understand the functional origin of this unique oligomeric structure, a series of rational noncatalytic, site-specific mutations have been made on Axe2. Some of these mutations led to a different dimeric form of the protein, which showed a significant reduction in catalytic activity. One of these double mutants, Axe2-Y184F-W190P, has recently been overexpressed, purified and crystallized. The best crystals obtained belonged to the orthorhombic space group P212121, with unit-cell parameters a = 71.1, b = 106.0, c = 378.6 Å. A full diffraction data set to 2.3 Å resolution has been collected from a flash-cooled crystal of this type at 100 K using synchrotron radiation. This data set is currently being used for the three-dimensional structure analysis of the Axe2-Y184F-W190P mutant in its dimeric form.

  4. Cognitive resilience to apolipoprotein E ε4: contributing factors in black and white older adults.

    PubMed

    Kaup, Allison R; Nettiksimmons, Jasmine; Harris, Tamara B; Sink, Kaycee M; Satterfield, Suzanne; Metti, Andrea L; Ayonayon, Hilsa N; Yaffe, Kristine

    2015-03-01

    Apolipoprotein E (APOE) ε4 is an established risk factor for cognitive decline and the development of dementia, but other factors may help to minimize its effects. Using APOE ε4 as an indicator of high risk, we investigated factors associated with cognitive resilience among black and white older adults who are APOE ε4 carriers. Participants included 2487 community-dwelling older (aged 69-80 years at baseline) black and white adults examined at 2 community clinics in the prospective cohort Health, Aging, and Body Composition (Health ABC) study. The baseline visits occurred from May 1997 through June 1998. Our primary analytic cohort consisted of 670 APOE ε4 carriers (329 black and 341 white participants) who were free of cognitive impairment at baseline and underwent repeated cognitive testing during an 11-year follow-up (through 2008) using the Modified Mini-Mental State Examination. We stratified all analyses by race. Using the Modified Mini-Mental State Examination scores, we assessed normative cognitive change in the entire cohort (n = 2487) and classified the APOE ε4 carriers as being cognitively resilient vs nonresilient by comparing their cognitive trajectories with those of the entire cohort. We then conducted bivariate analyses and multivariable random forest and logistic regression analyses to explore factors predictive of cognitive resilience in APOE ε4 carriers. Among white APOE ε4 carriers, the strongest predictors of cognitive resilience were, in relative order of importance, no recent negative life events, a higher literacy level, advanced age, a higher educational level, and more time spent reading. Among black APOE ε4 carriers, the strongest predictors of cognitive resilience were, in relative order of importance, a higher literacy level, a higher educational level, female sex, and the absence of diabetes mellitus. In follow-up logistic regression models, higher literacy level (adjusted odds ratio [OR], 9.50 [95% CI, 2.67-60.89]), a

  5. Association of apolipoprotein E (APOE) polymorphisms with warfarin maintenance dose in a northern Han Chinese population.

    PubMed

    Liu, Rui; Zhang, Kui; Gong, Zhi-zhong; Shi, Xin-miao; Zhang, Qian; Pan, Xiao-dong; Dong, Ran

    2016-02-24

    Apolipoprotein E (apoE) induces the uptake of vitamin K-rich lipoproteins by the liver, which likely affects inter-individual variation of warfarin dosing requirements. Associations between APOE polymorphisms and warfarin dosing were previously reported inconsistently among different ethnic groups, so the present study investigated this association in northern Han Chinese patients with mechanical heart valve prosthesis. A total of 186 patients who underwent mechanical heart valve replacement and attained a stable warfarin dose were included. APOE single nucleotide polymorphisms (SNPs) rs7412 and rs429358 were genotyped using Illumina SNP GoldenGate Assay. Genotyping results were confirmed by direct sequencing. PHASE v2.1 software was used to construct rs7412 and rs429358 haplotypes. The effects of different APOE genotypes on warfarin dose were analyzed statistically. The mean warfarin maintenance dose was 3.10 ± 0.96 mg/day, and the mean international normalized ratio (INR) was 2.09 ± 0.24. APOE E2, E3, and E4 allele frequencies were 11.6 %, 82.5 %, and 5.9 %, respectively. No E2/E2 or E4/E4 genotypes were detected in this population. E2/E3, E3/E3, E2/E4, and E3/E4 genotype frequencies were 21.0 %, 67.2 %, 2.2 %, and 9.7 %, respectively. Significant differences in warfarin dose requirements were observed among patients with E2/E3, E3/E3, and E3/E4 genotypes (p < 0.05). In post hoc comparison, daily warfarin maintenance doses were significantly higher in E2/E3 heterozygotes compared with E3/E3 homozygotes (p < 0.05), but no differences in dose requirements were found between E3/E4 and E3/E3, or E2/E3 and E3/E4 (p > 0.05). Patients were divided into low-intensity anticoagulant treatment group (1.6 ≤ INR <2.0) and relatively high-intensity anticoagulant treatment group (2.0 ≤ INR ≤ 2.5), and significantly higher warfarin dose requirements were observed in E2/E3 heterozygotes compared with E3/E3 homozygotes in both subgroups (p < 0.05). Multivariable analysis

  6. Apolipoprotein E Genotype and Sex Risk Factors for Alzheimer Disease: A Meta-analysis.

    PubMed

    Neu, Scott C; Pa, Judy; Kukull, Walter; Beekly, Duane; Kuzma, Amanda; Gangadharan, Prabhakaran; Wang, Li-San; Romero, Klaus; Arneric, Stephen P; Redolfi, Alberto; Orlandi, Daniele; Frisoni, Giovanni B; Au, Rhoda; Devine, Sherral; Auerbach, Sanford; Espinosa, Ana; Boada, Mercè; Ruiz, Agustín; Johnson, Sterling C; Koscik, Rebecca; Wang, Jiun-Jie; Hsu, Wen-Chuin; Chen, Yao-Liang; Toga, Arthur W

    2017-10-01

    It is unclear whether female carriers of the apolipoprotein E (APOE) ε4 allele are at greater risk of developing Alzheimer disease (AD) than men, and the sex-dependent association of mild cognitive impairment (MCI) and APOE has not been established. To determine how sex and APOE genotype affect the risks for developing MCI and AD. Twenty-seven independent research studies in the Global Alzheimer's Association Interactive Network with data on nearly 58 000 participants. Non-Hispanic white individuals with clinical diagnostic and APOE genotype data. Homogeneous data sets were pooled in case-control analyses, and logistic regression models were used to compute risks. Age-adjusted odds ratios (ORs) and 95% confidence intervals for developing MCI and AD were calculated for men and women across APOE genotypes. Participants were men and women between ages 55 and 85 years. Across data sets most participants were white, and for many participants, racial/ethnic information was either not collected or not known. Men (OR, 3.09; 95% CI, 2.79-3.42) and women (OR, 3.31; CI, 3.03-3.61) with the APOE ε3/ε4 genotype from ages 55 to 85 years did not show a difference in AD risk; however, women had an increased risk compared with men between the ages of 65 and 75 years (women, OR, 4.37; 95% CI, 3.82-5.00; men, OR, 3.14; 95% CI, 2.68-3.67; P = .002). Men with APOE ε3/ε4 had an increased risk of AD compared with men with APOE ε3/ε3. The APOE ε2/ε3 genotype conferred a protective effect on women (OR, 0.51; 95% CI, 0.43-0.61) decreasing their risk of AD more (P value = .01) than men (OR, 0.71; 95% CI, 0.60-0.85). There was no difference between men with APOE ε3/ε4 (OR, 1.55; 95% CI, 1.36-1.76) and women (OR, 1.60; 95% CI, 1.43-1.81) in their risk of developing MCI between the ages of 55 and 85 years, but women had an increased risk between 55 and 70 years (women, OR, 1.43; 95% CI, 1.19-1.73; men, OR, 1.07; 95% CI, 0.87-1.30; P = .05). There were no significant

  7. Effect of human apolipoprotein E genotype on the pathogenesis of experimental ocular HSV-1

    PubMed Central

    Bhattacharjee, Partha S.; Neumann, Donna M.; Foster, Timothy P.; Bouhanik, Sadallah; Clement, Christian; Vinay, Dass; Thompson, Hilary W.; Hill, James M.

    2008-01-01

    The isoform-specific role of human apolipoprotein E (apoE) has been assessed in a mouse model of ocular herpes. Female, age-matched transgenic mice knocked-in for the human allele apoE3 or apoE4 and their parent C57Bl/6 mice were inoculated corneally with HSV-1 strain KOS. Ocular HSV-1 pathogenesis was monitored through viral replication and clinical progression of stromal opacity and neovascularization by slit-lamp examination. Establishment of latency was determined by analysis of HSV-1 DNA (copy number) by specific real-time PCR in the cornea, trigeminal ganglia (TG), and brain. Representative groups of transgenic mice were sacrificed for the analysis of gene expression of vascular endothelial growth factor (VEGF) by reverse-transcription PCR, and apoE expression by Western blot analysis. At 6 days post-infection (P.I.), the ocular infectious HSV-1 titer was significantly higher (p < 0.05) in apoE4 mice compared with apoE3 and C57Bl/6 mice. Corneal neovascularization in apoE4 mice was significantly higher (p < 0.05) than apoE3 and C57Bl/6 mice. The onset of corneal opacity in apoE4 mice was accelerated during days 9--11 P.I.; however, no significant difference in severity was seen on P.I. days 15 and beyond. At 28 days P.I., infected mice of all genotypes had no significant differences in copy numbers (range 0--15) of HSV-1 DNA in their corneas, indicating that HSV-1 DNA copy numbers in cornea are independent of apoE isoform regulation. At 28 days P.I., both apoE4 and C57Bl/6 mice had a significantly higher (p = 0.001) number of copies of HSV-1 DNA in TG compared with apoE3. ApoE4 mice also had significantly higher (p = 0.001) copies of HSV-1 DNA in their TGs compared with C57Bl/6 mice. In brain, both apoE4 and C57Bl/6 mice had significantly higher numbers (p ≤ 0.03) of copies of HSV-1 DNA compared with apoE3 mice. However, the number of HSV-1 DNA copies in the brain of C57Bl/6 mice was not significantly different than that of apoE4 (p = 0.1). Comparative

  8. The Activation Domain of the Bovine Papillomavirus E2 Protein Mediates Association of DNA-Bound Dimers to form DNA Loops

    NASA Astrophysics Data System (ADS)

    Knight, Jonathan D.; Li, Rong; Botchan, Michael

    1991-04-01

    The E2 transactivator protein of bovine papillomavirus binds its specific DNA target sequence as a dimer. We have found that E2 dimers, performed in solution independent of DNA, exhibit substantial cooperativity of DNA binding as detected by both nitrocellulose filter retention and footprint analysis techniques. If the binding sites are widely spaced, E2 forms stable DNA loops visible by electron microscopy. When three widely separated binding sites reside on te DNA, E2 condenses the molecule into a bow-tie structure. This implies that each E2 dimer has at least two independent surfaces for multimerization. Two naturally occurring shorter forms of the protein, E2C and D8/E2, which function in vivo as repressors of transcription, do not form such loops. Thus, the looping function of E2 maps to the 161-amino acid activation domain. These results support the looping model of transcription activation by enhancers.

  9. Brief Communication: Plasma lipid oxidation predicts atherosclerotic status better than cholesterol in diabetic apolipoprotein E deficient mice.

    PubMed

    Petersen, Karen Ekkelund; Lykkesfeldt, Jens; Raun, Kirsten; Rakipovski, Günaj

    2017-01-01

    Increased levels of oxidative stress have been suggested to play a detrimental role in the development of diabetes-related vascular complications. Here, we investigated whether the concentration of malondialdehyde, a marker of lipid oxidation correlated to the degree of aortic plaque lesions in a proatherogenic diabetic mouse model. Three groups of apolipoprotein E knockout mice were studied for 20 weeks, a control, a streptozotocin-induced diabetic, and a diabetic enalapril-treated group. Enalapril was hypothesized to lower oxidative stress level and thus the plaque burden. Both diabetic groups were significantly different from the control group as they had higher blood glucose, HbA1c, total cholesterol, low-density lipoprotein, very low-density lipoprotein, together with a lower high-density lipoprotein concentration and body weight. Animals in the diabetic group had significantly higher plaque area and plasma malondialdehyde than controls. The two diabetic groups did not differ significantly in any measured characteristic. In summary, there was a positive correlation between plasma malondialdehyde concentration and aorta plaque area in apolipoprotein E knockout. Even though further investigation of the role of lipid oxidation in the development of atherosclerosis is warranted, these results suggest that biomarkers of lipid oxidation may be of value in the evaluation of cardiovascular risk.

  10. Differential effects of green tea-derived catechin on developing versus established atherosclerosis in apolipoprotein E-null mice.

    PubMed

    Chyu, Kuang-Yuh; Babbidge, Stephanie M; Zhao, Xiaoning; Dandillaya, Ram; Rietveld, Anton G; Yano, Juliana; Dimayuga, Paul; Cercek, Bojan; Shah, Prediman K

    2004-05-25

    Oxidative stress has been implicated in vascular injury and atherogenesis, and antioxidant treatment has shown favorable results in preclinical studies. Despite this, antioxidant therapy has failed to show benefit in clinical trials. Failure of antioxidants in clinical trials may be partly because such therapy is started after atherosclerosis is already well established, whereas the benefits in animal models may be results from early initiation of antioxidants while atherosclerosis is still evolving. To test this hypothesis, we evaluated the effect of epigallocatechin gallate (EGCG), the main antioxidant derived from green tea, on evolving and established atherosclerotic lesions in hypercholesterolemic apolipoprotein E-null mice. Established native aortic atherosclerotic lesions and evolving atherosclerotic lesions produced by periadventitial cuff injury to carotid arteries were assessed in mice after 21 and 42 days of treatment with daily intraperitoneal injections of EGCG (10 mg/kg) or PBS. EGCG treatment resulted in an increase in the antioxidant capacity in local vascular tissue and systemic circulation and reduced vascular smooth muscle cell proliferation and redox-sensitive gene activation in vitro. EGCG reduced cuff-induced evolving atherosclerotic plaque size at 21 and 42 days by 55% and 73%, respectively, compared with PBS treatment (P<0.05). Conversely, EGCG had no effect on established lesions in the aortic sinuses or the rest of the aorta. Our data suggest that antioxidant EGCG differentially reduces evolving atherosclerotic lesions without influencing established atherosclerosis in the apolipoprotein E-null mice.

  11. Generation of mice carrying a mutant apolipoprotein E gene inactivated by gene targeting in embryonic stem cells.

    PubMed Central

    Piedrahita, J A; Zhang, S H; Hagaman, J R; Oliver, P M; Maeda, N

    1992-01-01

    We have inactivated the endogenous apolipoprotein E (apoE) gene by using gene targeting in mouse embryonic stem (ES) cells. Two targeting plasmids were used, pJPB63 and pNMC109, both containing a neomycin-resistance gene that replaces a part of the apoE gene and disrupts its structure. ES cell colonies targeted after electroporation with plasmid pJPB63 were identified by the polymerase chain reaction (PCR) followed by genomic Southern analysis. Of 648 G418-resistant colonies analyzed, 9 gave a positive signal after PCR amplification, and 5 of them were confirmed as targeted by Southern blot analysis. The second plasmid, pNMC109, contains the negatively selectable thymidine kinase gene in addition to the neomycin-resistance gene. After electroporation with this plasmid, 177 colonies resistant both to G418 and ganciclovir were analyzed; 39 contained a disrupted apoE gene as determined by Southern blotting. Chimeric mice were generated by blastocyst injection with 6 of the targeted lines. One of the lines gave strong chimeras, three of which transmitted the disrupted apoE gene to their progeny. Mice homozygous for the disrupted gene were produced from the heterozygotes; they appear healthy, even though they have no apolipoprotein E in their plasma. Images PMID:1584779

  12. Quercetin improves macrophage reverse cholesterol transport in apolipoprotein E-deficient mice fed a high-fat diet.

    PubMed

    Cui, Yingjie; Hou, Pengbo; Li, Fahui; Liu, Qinghua; Qin, Shucun; Zhou, Guanghai; Xu, Xuelian; Si, Yanhong; Guo, Shoudong

    2017-01-14

    Quercetin, one of the most widely distributed flavonoids in plants, has been demonstrated to reduce hyperlipidaemia and atherosclerotic lesion formation. Reverse cholesterol transport (RCT) plays a crucial role in exporting cholesterol from peripheral cells, which is one mechanism utilized in the prevention and treatment of atherosclerosis. The aim of this study is to investigate whether quercetin reduces lipid accumulation by improving RCT in vivo. Apolipoprotein E-deficient mice fed a high-fat diet were used to investigate the effect of quercetin on RCT by an isotope tracing method, and the underlying mechanisms were clarified by molecular techniques. These novel results demonstrated that quercetin significantly improved [(3)H]-cholesterol transfer from [(3)H]-cholesterol-loaded macrophages to the plasma (approximately 34% increase), liver (30% increase), and bile (50% increase) and finally to the feces (approximately 40% increase) for excretion in apolipoprotein E-deficient mice fed a high-fat diet. Furthermore, quercetin markedly increased the cholesterol accepting ability of plasma and high-density lipoprotein (HDL) and dramatically decreased the content of malondialdehyde in plasma and oxidized phosphocholine carried by HDL. Therefore, the underlying mechanisms of quercetin in improving RCT may be partially due to the elevated cholesterol accepting ability of HDL, the increased expression levels of proteins related to RCT, such as ATP-binding cassettes (ABC) A1 and G1, and the improved antioxidant activity of HDL. Quercetin accelerates RCT in an atherosclerosis model, which is helpful in clarifying the lipid-lowering effect of quercetin.

  13. Icariin improves eNOS/NO pathway to prohibit the atherogenesis of apolipoprotein E-null mice.

    PubMed

    Xiao, Hong-Bo; Sui, Guo-Guang; Lu, Xiang-Yang

    2016-12-22

    Impaired endothelial nitric oxide synthase (eNOS)/nitric oxide (NO) pathway induces atherogenesis. The present study examined whether icariin improves the eNOS/NO pathway to prohibit the atherogenesis of apolipoprotein E-null (ApoE(-/-)) mice. In vitro, primary human umbilical vein endothelial cells (HUVECs) were randomly divided into 7 groups: control; vehicle; icariin 10; lyphosphatidylcholine (LPC) group; LPC + icariin 1; LPC + icariin 3; and LPC + icariin 10. In vivo, 80 mice were separated randomly into 4 groups (n = 20): control, ApoE(-/-), ApoE(-/-) + icariin 10, and ApoE(-/-) + icariin 30. ApoE(-/-) mice had significantly more atherosclerosis in the aortic root together with increased aortic ROS production, body mass, plasma triglyceride (TG) and total cholesterol (TC) concentration, decreased aortic eNOS expression, and plasma NO concentration. LPC (10 μg/mL) treatment induced a big decline in NO level in the conditioned medium and eNOS expression, and an increase in intracellular reactive oxygen species (ROS) production in HUVECs. Icariin treatment decreased atherogenesis, ROS production, body mass, plasma TG concentration, and plasma TC concentration, and increased NO concentration and eNOS expression. These findings suggested icariin could improve eNOS/NO-pathway to prohibit the atherogenesis of apolipoprotein E-null mice by restraining oxidative stress.

  14. Pallidal neuronal apolipoprotein E in pantothenate kinase-associated neurodegeneration recapitulates ischemic injury to the globus pallidus.

    PubMed

    Woltjer, Randall L; Reese, Lindsay C; Richardson, Brian E; Tran, Huong; Green, Sarah; Pham, Thao; Chalupsky, Megan; Gabriel, Isabella; Light, Tyler; Sanford, Lynn; Jeong, Suh Young; Hamada, Jeffrey; Schwanemann, Leila K; Rogers, Caleb; Gregory, Allison; Hogarth, Penelope; Hayflick, Susan J

    2015-12-01

    Pantothenate kinase-associated neurodegeneration (PKAN) is a progressive movement disorder that is due to mutations in PANK2. Pathologically, it is a member of a class of diseases known as neurodegeneration with brain iron accumulation (NBIA) and features increased tissue iron and ubiquitinated proteinaceous aggregates in the globus pallidus. We have previously determined that these aggregates represent condensed residue derived from degenerated pallidal neurons. However, the protein content, other than ubiquitin, of these aggregates remains unknown. In the present study, we performed biochemical and immunohistochemical studies to characterize these aggregates and found them to be enriched in apolipoprotein E that is poorly soluble in detergent solutions. However, we did not determine a significant association between APOE genotype and the clinical phenotype of disease in our database of 81 cases. Rather, we frequently identified similar ubiquitin- and apolipoprotein E-enriched lesions in these neurons in non-PKAN patients in the penumbrae of remote infarcts that involve the globus pallidus, and occasionally in other brain sites that contain large γ-aminobutyric acid (GABA)ergic neurons. Our findings, taken together, suggest that tissue or cellular hypoxic/ischemic injury within the globus pallidus may underlie the pathogenesis of PKAN. Copyright © 2015. Published by Elsevier Inc.

  15. The multiple forms of bovine seminal ribonuclease: structure and stability of a C-terminal swapped dimer.

    PubMed

    Sica, Filomena; Pica, Andrea; Merlino, Antonello; Russo Krauss, Irene; Ercole, Carmine; Picone, Delia

    2013-11-29

    Bovine seminal ribonuclease (BS-RNase) acquires an interesting anti-tumor activity associated with the swapping on the N-terminal. The first direct experimental evidence on the formation of a C-terminal swapped dimer (C-dimer) obtained from the monomeric derivative of BS-RNase, although under non-native conditions, is here reported. The X-ray model of this dimer reveals a quaternary structure different from that of the C-dimer of RNase A, due to the presence of three mutations in the hinge peptide 111-116. The mutations increase the hinge peptide flexibility and decrease the stability of the C-dimer against dissociation. The biological implications of the structural data are also discussed.

  16. Effect of dimer dissociation on activity and thermostability of the alpha-glucuronidase from Geobacillus stearothermophilus: dissecting the different oligomeric forms of family 67 glycoside hydrolases.

    PubMed

    Shallom, Dalia; Golan, Gali; Shoham, Gil; Shoham, Yuval

    2004-10-01

    The oligomeric organization of enzymes plays an important role in many biological processes, such as allosteric regulation, conformational stability and thermal stability. alpha-Glucuronidases are family 67 glycosidases that cleave the alpha-1,2-glycosidic bond between 4-O-methyl-D-glucuronic acid and xylose units as part of an array of hemicellulose-hydrolyzing enzymes. Currently, two crystal structures of alpha-glucuronidases are available, those from Geobacillus stearothermophilus (AguA) and from Cellvibrio japonicus (GlcA67A). Both enzymes are homodimeric, but surprisingly their dimeric organization is different, raising questions regarding the significance of dimerization for the enzymes' activity and stability. Structural comparison of the two enzymes suggests several elements that are responsible for the different dimerization organization. Phylogenetic analysis shows that the alpha-glucuronidases AguA and GlcA67A can be classified into two distinct subfamilies of bacterial alpha-glucuronidases, where the dimer-forming residues of each enzyme are conserved only within its own subfamily. It seems that the different dimeric forms of AguA and GlcA67A represent the two alternative dimeric organizations of these subfamilies. To study the biological significance of the dimerization in alpha-glucuronidases, we have constructed a monomeric form of AguA by mutating three of its interface residues (W328E, R329T, and R665N). The activity of the monomer was significantly lower than the activity of the wild-type dimeric AguA, and the optimal temperature for activity of the monomer was around 35 degrees C, compared to 65 degrees C of the wild-type enzyme. Nevertheless, the melting temperature of the monomeric protein, 72.9 degrees C, was almost identical to that of the wild-type, 73.4 degrees C. It appears that the dimerization of AguA is essential for efficient catalysis and that the dissociation into monomers results in subtle conformational changes in the structure

  17. Effect of Dimer Dissociation on Activity and Thermostability of the α-Glucuronidase from Geobacillus stearothermophilus: Dissecting the Different Oligomeric Forms of Family 67 Glycoside Hydrolases

    PubMed Central

    Shallom, Dalia; Golan, Gali; Shoham, Gil; Shoham, Yuval

    2004-01-01

    The oligomeric organization of enzymes plays an important role in many biological processes, such as allosteric regulation, conformational stability and thermal stability. α-Glucuronidases are family 67 glycosidases that cleave the α-1,2-glycosidic bond between 4-O-methyl-d-glucuronic acid and xylose units as part of an array of hemicellulose-hydrolyzing enzymes. Currently, two crystal structures of α-glucuronidases are available, those from Geobacillus stearothermophilus (AguA) and from Cellvibrio japonicus (GlcA67A). Both enzymes are homodimeric, but surprisingly their dimeric organization is different, raising questions regarding the significance of dimerization for the enzymes' activity and stability. Structural comparison of the two enzymes suggests several elements that are responsible for the different dimerization organization. Phylogenetic analysis shows that the α-glucuronidases AguA and GlcA67A can be classified into two distinct subfamilies of bacterial α-glucuronidases, where the dimer-forming residues of each enzyme are conserved only within its own subfamily. It seems that the different dimeric forms of AguA and GlcA67A represent the two alternative dimeric organizations of these subfamilies. To study the biological significance of the dimerization in α-glucuronidases, we have constructed a monomeric form of AguA by mutating three of its interface residues (W328E, R329T, and R665N). The activity of the monomer was significantly lower than the activity of the wild-type dimeric AguA, and the optimal temperature for activity of the monomer was around 35°C, compared to 65°C of the wild-type enzyme. Nevertheless, the melting temperature of the monomeric protein, 72.9°C, was almost identical to that of the wild-type, 73.4°C. It appears that the dimerization of AguA is essential for efficient catalysis and that the dissociation into monomers results in subtle conformational changes in the structure which indirectly influence the active site region

  18. The HC fragment of tetanus toxin forms stable, concentration-dependent dimers via an intermolecular disulphide bond.

    PubMed

    Qazi, Omar; Bolgiano, Barbara; Crane, Dennis; Svergun, Dmitri I; Konarev, Petr V; Yao, Zhong-Ping; Robinson, Carol V; Brown, Katherine A; Fairweather, Neil

    2007-01-05

    Protein oligomerisation is a prerequisite for the toxicity of a number of bacterial toxins. Examples include the pore-forming cytotoxin streptolysin O, which oligomerises to form large pores in the membrane and the protective antigen of anthrax toxin, where a heptameric complex is essential for the delivery of lethal factor and edema factor to the cell cytosol. Binding of the clostridial neurotoxins to receptors on neuronal cells is well characterised, but little is known regarding the quaternary structure of these toxins and the role of oligomerisation in the intoxication process. We have investigated the oligomerisation of the receptor binding domain (H(C)) of tetanus toxin, which retains the binding and trafficking properties of the full-length toxin. Electrophoresis, size exclusion chromatography and mass spectrometry were used to demonstrate that H(C) undergoes concentration-dependent oligomerisation in solution. Reducing agents were found to affect H(C) oligomerisation and, using mutagenesis, Cys869 was shown to be essential for this process. Furthermore, the oligomeric state and quaternary structure of H(C) in solution was assessed using synchrotron small-angle X-ray scattering. Ab initio shape analysis and rigid body modelling coupled with mutagenesis data allowed the construction of an unequivocal model of dimeric H(C) in solution. We propose a possible mechanism for H(C) oligomerisation and discuss how this may relate to toxicity.

  19. Dimerization, oligomerization, and aggregation of human amyotrophic lateral sclerosis copper/zinc superoxide dismutase 1 protein mutant forms in live cells.

    PubMed

    Kim, Jiho; Lee, Honggun; Lee, Joo Hyun; Kwon, Do-yoon; Genovesio, Auguste; Fenistein, Denis; Ogier, Arnaud; Brondani, Vincent; Grailhe, Regis

    2014-05-23

    More than 100 copper/zinc superoxide dismutase 1 (SOD1) genetic mutations have been characterized. These mutations lead to the death of motor neurons in ALS. In its native form, the SOD1 protein is expressed as a homodimer in the cytosol. In vitro studies have shown that SOD1 mutations impair the dimerization kinetics of the protein, and in vivo studies have shown that SOD1 forms aggregates in patients with familial forms of ALS. In this study, we analyzed WT SOD1 and 9 mutant (mt) forms of the protein by non-invasive fluorescence techniques. Using microscopic techniques such as fluorescence resonance energy transfer, fluorescence complementation, image-based quantification, and fluorescence correlation spectroscopy, we studied SOD1 dimerization, oligomerization, and aggregation. Our results indicate that SOD1 mutations lead to an impairment in SOD1 dimerization and, subsequently, affect protein aggregation. We also show that SOD1 WT and mt proteins can dimerize. However, aggregates are predominantly composed of SOD1 mt proteins.

  20. LexA repressor forms stable dimers in solution. The role of specific dna in tightening protein-protein interactions.

    PubMed

    Mohana-Borges, R; Pacheco, A B; Sousa, F J; Foguel, D; Almeida, D F; Silva, J L

    2000-02-18

    Cooperativity in the interactions among proteins subunits and DNA is crucial for DNA recognition. LexA repressor was originally thought to bind DNA as a monomer, with cooperativity leading to tighter binding of the second monomer. The main support for this model was a high value of the dissociation constant for the LexA dimer (micromolar range). Here we show that the protein is a dimer at nanomolar concentrations under different conditions. The reversible dissociation of LexA dimer was investigated by the effects of hydrostatic pressure or urea, using fluorescence emission and polarization to monitor the dissociation process. The dissociation constant lies in the picomolar range (lower than 20 pM). LexA monomers associate with an unusual large volume change (340 ml/mol), indicating the burial of a large surface area upon dimerization. Whereas nonspecific DNA has no stabilizing effect, specific DNA induces tightening of the dimer and a 750-fold decrease in the K(d). In contrast to the previous model, a tight dimer rather than a monomer is the functional repressor. Accordingly, the LexA dimer only loses its ability to recognize a specific DNA sequence by RecA-induced autoproteolysis. Our work provides insights into the linkage between protein-protein interactions, DNA recognition, and DNA repair.

  1. The apolipoprotein E genotype predicts longitudinal transitions to mild cognitive impairment but not to Alzheimer's dementia: findings from a nationally representative study.

    PubMed

    Brainerd, C J; Reyna, V F; Petersen, R C; Smith, G E; Kenney, A E; Gross, C J; Taub, E S; Plassman, B L; Fisher, G G

    2013-01-01

    The ε4 allele of the apolipoprotein E (APOE) genotype is the most widely accepted genetic risk factor for Alzheimer's dementia (AD), but findings on whether it is a risk factor for the AD prodrome, mild cognitive impairment (MCI), have been inconsistent. In a prospective longitudinal design, we investigated (a) whether transitions to MCI and other forms of neurocognitive impairment without dementia (CIND) are more frequent among normal ε4 carriers than among noncarriers and (b) whether subsequent transitions to AD from MCI and from other forms of CIND are more frequent among ε4 carriers than among noncarriers. The frequency of the ε4 allele was studied in older adults (mean age > 70), who had participated in two or more waves of neuropsychological testing and diagnosis in the Aging, Demographics, and Memory Study (ADAMS) of the United States Department of Health and Human Services, National Institutes of Health, National Institute on Aging's Health and Retirement Study, conducted by the University of Michigan. The association between ε4 and longitudinal transitions to specific types of CIND and dementia can be determined with this data set. Epsilon 4 increased the rate of progression from normal functioning to MCI (58% of new diagnoses were carriers) but not to other forms of CIND. The rate of progression to AD from MCI or from other forms of CIND was not increased by ε4. The results support the hypothesis that ε4 is a risk factor for transitions from normal functioning to MCI but not for subsequent transitions to AD. In the ADAMS sample, the reason ε4 is elevated in AD individuals is because it is already elevated in MCI individuals, who are the primary source of new AD diagnoses.

  2. Evidence for apolipoprotein E {epsilon}4 association in early-onset Alzheimer`s patients with late-onset relatives

    SciTech Connect

    Perez-Tur, J.; Delacourte, A.; Chartier-Harlin, M.C.

    1995-12-18

    Recently several reports have extended the apolipoprotein E (APOE) {epsilon}4 association found in late-onset Alzheimer`s disease (LOAD) patients to early-onset (EO) AD patients. We have studied this question in a large population of 119 EOAD patients (onset {<=}60 years) in which family history was carefully assessed and in 109 controls. We show that the APOE {epsilon}A allele frequency is increased only in the subset of patients who belong to families where LOAD secondary cases are present. Our sampling scheme permits us to demonstrate that, for an individual, bearing at least one {epsilon}4 allele increases both the risk of AD before age 60 and the probability of belonging to a family with late-onset affected subjects. Our results suggest that a subset of EOAD cases shares a common determinism with LOAD cases. 19 refs., 3 tabs.

  3. Allelic association but only weak evidence for linkage to the apolipoprotein E locus in late-onset Swedish Alzheimer families

    SciTech Connect

    Liu, L.; Forsell, C.; Lilius, L.

    1996-05-31

    An association between the {epsilon}4 allele of the apolipoprotein E gene (APOE) and late-onset Alzheimer`s disease (AD) was recently demonstrated. In order to confirm the association and to gauge the ability of standard genetic linkage methods to identify susceptibility genes, we investigated 15 Swedish late-onset AD families. We found an association of familial AD to the APOE {epsilon}4 allele (P = 0.01) but no indication of linkage to the APOE region using 2-point linkage analysis, and only weak evidence using the affected pedigree-member (APM) method. Our results confirm an APOE {epsilon}4 association with late-onset familial AD and indicate that susceptibility genes can easily be missed when using standard lod score and APM genetic linkage analysis. 19 refs., 1 fig., 4 tabs.

  4. Proteomic Profile of Unstable Atheroma Plaque: Increased Neutrophil Defensin 1, Clusterin, and Apolipoprotein E Levels in Carotid Secretome.

    PubMed

    Aragonès, Gemma; Auguet, Teresa; Guiu-Jurado, Esther; Berlanga, Alba; Curriu, Marta; Martinez, Salomé; Alibalic, Ajla; Aguilar, Carmen; Hernández, Esteban; Camara, María-Luisa; Canela, Núria; Herrero, Pol; Ruyra, Xavier; Martín-Paredero, Vicente; Richart, Cristóbal

    2016-03-04

    Because of the clinical significance of carotid atherosclerosis, the search for novel biomarkers has become a priority. The aim of the present study was to compare the protein secretion profile of the carotid atherosclerotic plaque (CAP, n = 12) and nonatherosclerotic mammary artery (MA, n = 10) secretomes. We used a nontargeted proteomic approach that incorporated tandem immunoaffinity depletion, iTRAQ labeling, and nanoflow liquid chromatography coupled to high-resolution mass spectrometry. In total, 162 proteins were quantified, of which 25 showed statistically significant differences in secretome levels between carotid atherosclerotic plaque and nondiseased mammary artery. We found increased levels of neutrophil defensin 1, apolipoprotein E, clusterin, and zinc-alpha-2-glycoprotein in CAP secretomes. Results were validated by ELISA assays. Also, differentially secreted proteins are involved in pathways such as focal adhesion and leukocyte transendothelial migration. In conclusion, this study provides a subset of identified proteins that are differently expressed in secretomes of clinical significance.

  5. Enhanced synthesis and secretion of apolipoprotein E from sciatic nerves of streptozotocin-induced diabetic rats after injury

    SciTech Connect

    Ishibashi, S.; Yamada, N.; Oka, Y.; Shimano, H.; Mori, N.; Yoon, T.H.; Shimada, M.; Kanazawa, Y.; Akanuma, Y.; Murase, T.

    1988-08-30

    To elucidate the pathogenesis of diabetic neuropathy, synthesis and secretion of apolipoprotein E (apo E) from sciatic nerves after injury was studied in normal and streptozotocin-induced diabetic rats. Seven, 14, 28, 45 and 59 days after making crush injury on sciatic nerves with concomitant administration of streptozotocin (50 mg/kg body weight), the nerves were taken out and incubated with (/sup 35/S)methionine. The (/sup 35/S)labeled apo E was precipitated with specific antiserum. The amounts of apo E secreted into medium by nerves of diabetic rats were 7 times greater than those of non-diabetic rats 7 days after injury. This enhanced secretion of apo E was relatively selective for this protein, since the ratio of the immunoprecipitable apo E to the TCA preciptitable protein in the medium increased in diabetic rats. Intriguing possibility deduced from these results is that the secretion of apo E is involved in the development of diabetic neuropathy.

  6. Characterization of the unfolding process of the tetrameric and dimeric forms of Cratylia mollis seed lectin (CRAMOLL 1): effects of natural fragmentation on protein stability.

    PubMed

    Varejão, Nathalia; Correia, Maria Tereza S; Foguel, Debora

    2011-08-30

    pCRAMOLL 1 is a major, non-glycosylated isolectin found in seeds of Cratylia mollis, which belongs to the Leguminosae family and the Diocleinae subtribe. The lectin (~25 kDa) consists of 236 amino acids, sharing 82% identity and virtually identical topological architecture with concanavalin A. Both lectins also share the same pH-dependent dimer-tetramer equilibrium and the ability to recognize Glc/Man moieties. Intricate post-translational events occurring in Diocleinae seed cotyledons result in a mixture of intact and fragmented monomers within the oligomeric assemblies of pCRAMOLL 1. In an earlier report, we demonstrated the production, purification, and characterization of the bacterially expressed form of CRAMOLL 1 (rCRAMOLL 1). The recombinant lectin retained sugar-binding activity and several other biophysical properties of pCRAMOLL 1, but its tetramers, which are composed of intact monomers only, show little enhancement in stability when probed with acidification, high temperatures, or hydrostatic pressure. Here we examined the urea-induced unfolding of the nonfragmented tetramers and dimers of rCRAMOLL 1 and compared this behavior with that of the mixed plant lectin counterparts. Using fluorescence, circular dichroism, size-exclusion chromatography, and chemical cross-linking experiments, we posited that the absence of fragmentation lent greater firmness to tetramers, but not to dimers. Dimeric and tetrameric pCRAMOLL 1 unfolded via a compact monomeric intermediate. In contrast, dimers of rCRAMOLL 1 behaved similarly to the plant dimer counterpart, but its tetrameric form remarkably showed no evidence of such partially unfolded monomers. By analyzing the crystal structure of pCRAMOLL 1, we were able to dissect the importance of the fragmentation to lectin stability.

  7. Plant γ-Tubulin Interacts with αβ-Tubulin Dimers and Forms Membrane-Associated Complexes

    PubMed Central

    Dryková, Denisa; Cenklová, Vĕra; Sulimenko, Vadym; Volc, Jindr̆ich; Dráber, Pavel; Binarová, Pavla

    2003-01-01

    γ-Tubulin is assumed to participate in microtubule nucleation in acentrosomal plant cells, but the underlying molecular mechanisms are still unknown. Here, we show that γ-tubulin is present in protein complexes of various sizes and different subcellular locations in Arabidopsis and fava bean. Immunoprecipitation experiments revealed an association of γ-tubulin with αβ-tubulin dimers. γ-Tubulin cosedimented with microtubules polymerized in vitro and localized along their whole length. Large γ-tubulin complexes resistant to salt treatment were found to be associated with a high-speed microsomal fraction. Blue native electrophoresis of detergent-solubilized microsomes showed that the molecular mass of the complexes was >1 MD. Large γ-tubulin complexes were active in microtubule nucleation, but nucleation activity was not observed for the smaller complexes. Punctate γ-tubulin staining was associated with microtubule arrays, accumulated with short kinetochore microtubules interacting in polar regions with membranes, and localized in the vicinity of nuclei and in the area of cell plate formation. Our results indicate that the association of γ-tubulin complexes with dynamic membranes might ensure the flexibility of noncentrosomal microtubule nucleation. Moreover, the presence of other molecular forms of γ-tubulin suggests additional roles for this protein species in microtubule organization. PMID:12566585

  8. Effect of tocopherol on atherosclerosis, vascular function, and inflammation in apolipoprotein E knockout mice with subtotal nephrectomy.

    PubMed

    Shing, Cecilia M; Fassett, Robert G; Peake, Jonathan M; Coombes, Jeff S

    2014-12-01

    Inflammation and endothelial dysfunction contribute to cardiovascular disease, prevalent in chronic kidney disease (CKD). Antioxidant supplements such as tocopherols may reduce inflammation and atherosclerosis. This study aimed to investigate the effect of tocopherol supplementation on vascular function, aortic plaque formation, and inflammation in apolipoprotein E(-/-) mice with 5/6 nephrectomy as a model of combined cardiovascular and kidney disease. Nephrectomized mice were assigned to a normal chow diet group (normal chow), a group receiving 1000 mg/kg diet of α-tocopherol supplementation or a group receiving 1000 mg/kg diet mixed-tocopherol (60% γ-tocopherol). Following 12 weeks, in vitro aortic endothelial-independent relaxation was enhanced with both α-tocopherol and mixed-tocopherol (P < 0.05), while mixed-tocopherol enhanced aortic contraction at noradrenaline concentrations of 3 × 10(-7) M to 3 × 10(-5) M (P < 0.05), when compared to normal chow. Supplementation with α- and mixed-tocopherol reduced systemic concentrations of IL-6 (P < 0.001 and P < 0.001, respectively) and IL-10 (P < 0.05 and P < 0.001, respectively), while α-tocopherol also reduced MCP-1 (P < 0.05) and tumor necrosis factor (TNF)-α (P < 0.05). Aortic sinus plaque area was significantly reduced with α-tocopherol supplementation when compared to normal chow (P < 0.01). Tocopherol supplementation favorably influenced vascular function and cytokine profile, while it was also effective in reducing atherosclerosis in the apolipoprotein E(-/-) mouse with CKD. © 2014 John Wiley & Sons Ltd.

  9. Proteomic Analysis of Plasma from California Sea Lions (Zalophus californianus) Reveals Apolipoprotein E as a Candidate Biomarker of Chronic Domoic Acid Toxicosis

    PubMed Central

    Neely, Benjamin A.; Ferrante, Jason A.; Chaves, J. Mauro; Soper, Jennifer L.; Almeida, Jonas S.; Arthur, John M.; Gulland, Frances M. D.; Janech, Michael G.

    2015-01-01

    Domoic acid toxicosis (DAT) in California sea lions (Zalophus californianus) is caused by exposure to the marine biotoxin domoic acid and has been linked to massive stranding events and mortality. Diagnosis is based on clinical signs in addition to the presence of domoic acid in body fluids. Chronic DAT further is characterized by reoccurring seizures progressing to status epilepticus. Diagnosis of chronic DAT is often slow and problematic, and minimally invasive tests for DAT have been the focus of numerous recent biomarker studies. The goal of this study was to retrospectively profile plasma proteins in a population of sea lions with chronic DAT and those without DAT using two dimensional gel electrophoresis to discover whether individual, multiple, or combinations of protein and clinical data could be utilized to identify sea lions with DAT. Using a training set of 32 sea lion sera, 20 proteins and their isoforms were identified that were significantly different between the two groups (p<0.05). Interestingly, 11 apolipoprotein E (ApoE) charge forms were decreased in DAT samples, indicating that ApoE charge form distributions may be important in the progression of DAT. In order to develop a classifier of chronic DAT, an independent blinded test set of 20 sea lions, seven with chronic DAT, was used to validate models utilizing ApoE charge forms and eosinophil counts. The resulting support vector machine had high sensitivity (85.7% with 92.3% negative predictive value) and high specificity (92.3% with 85.7% positive predictive value). These results suggest that ApoE and eosinophil counts along with machine learning can perform as a robust and accurate tool to diagnose chronic DAT. Although this analysis is specifically focused on blood biomarkers and routine clinical data, the results demonstrate promise for future studies combining additional variables in multidimensional space to create robust classifiers. PMID:25919366

  10. Proteomic Analysis of Plasma from California Sea Lions (Zalophus californianus) Reveals Apolipoprotein E as a Candidate Biomarker of Chronic Domoic Acid Toxicosis.

    PubMed

    Neely, Benjamin A; Ferrante, Jason A; Chaves, J Mauro; Soper, Jennifer L; Almeida, Jonas S; Arthur, John M; Gulland, Frances M D; Janech, Michael G

    2014-01-01

    Domoic acid toxicosis (DAT) in California sea lions (Zalophus californianus) is caused by exposure to the marine biotoxin domoic acid and has been linked to massive stranding events and mortality. Diagnosis is based on clinical signs in addition to the presence of domoic acid in body fluids. Chronic DAT further is characterized by reoccurring seizures progressing to status epilepticus. Diagnosis of chronic DAT is often slow and problematic, and minimally invasive tests for DAT have been the focus of numerous recent biomarker studies. The goal of this study was to retrospectively profile plasma proteins in a population of sea lions with chronic DAT and those without DAT using two dimensional gel electrophoresis to discover whether individual, multiple, or combinations of protein and clinical data could be utilized to identify sea lions with DAT. Using a training set of 32 sea lion sera, 20 proteins and their isoforms were identified that were significantly different between the two groups (p<0.05). Interestingly, 11 apolipoprotein E (ApoE) charge forms were decreased in DAT samples, indicating that ApoE charge form distributions may be important in the progression of DAT. In order to develop a classifier of chronic DAT, an independent blinded test set of 20 sea lions, seven with chronic DAT, was used to validate models utilizing ApoE charge forms and eosinophil counts. The resulting support vector machine had high sensitivity (85.7% with 92.3% negative predictive value) and high specificity (92.3% with 85.7% positive predictive value). These results suggest that ApoE and eosinophil counts along with machine learning can perform as a robust and accurate tool to diagnose chronic DAT. Although this analysis is specifically focused on blood biomarkers and routine clinical data, the results demonstrate promise for future studies combining additional variables in multidimensional space to create robust classifiers.

  11. Expression of the very low-density lipoprotein receptor (VLDL-r), an apolipoprotein-E receptor, in the central nervous system and in Alzheimer`s disease

    SciTech Connect

    Christie, R.H.; Chung, Haeyong; Rebeck, G.W.; Hyman, B.T.

    1996-04-01

    The very low density lipoprotein receptor (VLDL-r) is a cell-surface molecule specialized for the internalization of multiple diverse ligands, including apolipoprotein E (apoE)-containing lipoprotein particles, via clathrin-coated pits. Its structure is similar to the low-density lipoprotein receptor (LDL-r), although the two have substantially different systemic distributions and regulatory pathways. The present work examines the distribution of VLDL-r in the central nervous system (CNS) and in relation to senile plaques in Alzheimer disease (AD). VLDL-r is present on resting and activated microglia, particularly those associated with senile plaques (SPs). VLDL-r immunoreactivity is also found in cortical neurons. Two exons of VLDL-r mRNA are differentially spliced in the mature receptor mRNA. One set of splice forms gives rise to receptors containing (or lacking) an extracellular O-linked glycosylation domain near the transmembrane portion of the molecule. The other set of splice forms appears to be brain-specific, and is responsible for the presence or absence of one of the cysteine-rich repeat regions in the binding region of the molecule. Ratios of the receptor variants generated from these splice forms do not differ substantially across different cortical areas or in AD. We hypothesize that VLDL-r might contribute to metabolism of apoE and apoE/A{beta} complexes in the brain. Further characterization of apoE receptors in Alzheimer brain may help lay the groundwork for understanding the role of apoE in the CNS and in the pathophysiology of AD. 43 refs., 5 figs.

  12. Apolipoprotein e4 Is Associated with More Rapid Decline in Odor Identification than in Odor Threshold or Dementia Rating Scale Scores

    ERIC Educational Resources Information Center

    Calhoun-Haney, R.; Murphy, C.

    2005-01-01

    Individuals with the apolipoprotein E e4 genetic risk factor for Alzheimer's disease (AD) show deficits in olfactory function. The purpose of the present study was to examine longitudinally odor identification (odor ID), odor threshold, picture identification, and global cognitive status in allele positive (e4+) and negative (e4-) persons.…

  13. Apolipoprotein E polymorphisms and postprandial triglyceridemia before and after fenofibrate treatment in the Genetics of Lipid Lowering and Diet Network (GOLDN) Study

    USDA-ARS?s Scientific Manuscript database

    Background: While much is known about the effect of Apolipoprotein E (APOE) alleles on fasting lipid concentrations, less is known about the effect of APOE alleles on postprandial triglyceridemia or the triglyceride response to fenofibrate. Methods and Results: We evaluated the effects of the APOE l...

  14. Apolipoprotein e4 Is Associated with More Rapid Decline in Odor Identification than in Odor Threshold or Dementia Rating Scale Scores

    ERIC Educational Resources Information Center

    Calhoun-Haney, R.; Murphy, C.

    2005-01-01

    Individuals with the apolipoprotein E e4 genetic risk factor for Alzheimer's disease (AD) show deficits in olfactory function. The purpose of the present study was to examine longitudinally odor identification (odor ID), odor threshold, picture identification, and global cognitive status in allele positive (e4+) and negative (e4-) persons.…

  15. Dietary Soy Protein Isolate Ameliorates Atherosclerotic Lesions in Apolipoprotein E-Deficient Mice Potentially by Inhibiting Monocyte Chemoattractant Protein-1 Expression

    USDA-ARS?s Scientific Manuscript database

    Soy-based diets reportedly protect against the development of atherosclerosis; however, the underlying mechanism(s) for this protection remains unknown. In this report, the mechanism(s) contributing to the atheroprotective effects of a soy-based diet was addressed using the apolipoprotein E knockout...

  16. Everolimus limits aortic aneurysm in the apolipoprotein E-deficient mouse by downregulating C-C chemokine receptor 2 positive monocytes.

    PubMed

    Moran, Corey S; Jose, Roby J; Moxon, Joseph V; Roomberg, Alicia; Norman, Paul E; Rush, Catherine; Körner, Heinrich; Golledge, Jonathan

    2013-04-01

    We aimed to determine the effect of mechanistic target of rapamycin inhibitor everolimus on abdominal aortic aneurysm within the angiotensin II (A2)-infused apolipoprotein E-deficient mouse model. Abdominal aortic aneurysm was induced via subcutaneous infusion of A2. Flow cytometry demonstrated increased circulating and aortic C-C chemokine receptor 2 (CCR2) monocytes during A2 infusion. The number of CCR2 monocytes present within the aorta was positively correlated with suprarenal aortic diameter. Simultaneous infusion of everolimus via a second subcutaneous osmotic micropump inhibited A2-induced aortic dilatation. Using flow cytometry and Western blot analysis, decreased aortic dilatation was associated with reduced development of CCR2 bone marrow monocytes, fewer numbers of circulating CCR2 monocytes, and lower aortic CCR2 concentration. In vitro, everolimus inhibited A2-stimulated production of interferon (IFN)-γ and IFNγ-induced CCR2 expression in apolipoprotein E-deficient mouse bone marrow monocytes. Further, everolimus diminished IFNγ/lipopolysaccharide-stimulated M1 polarization in apolipoprotein E-deficient mouse bone marrow monocyte-differentiated macrophages. Systemic administration of everolimus limits aortic aneurysm in the A2-infused apolipoprotein E-deficient mouse model via suppressed development of bone marrow CCR2 monocytes and reduced egress of these cells into the circulation.

  17. The double-length tyrosyl-tRNA synthetase from the eukaryote Leishmania major forms an intrinsically asymmetric pseudo-dimer

    PubMed Central

    Larson, Eric T; Kim, Jessica E; Castaneda, Lisa J; Napuli, Alberto J; Zhang, Zhongsheng; Fan, Erkang; Zucker, Frank H; Verlinde, Christophe LMJ; Buckner, Frederick S; Van Voorhis, Wesley C; Hol, Wim G J; Merritt, Ethan A

    2011-01-01

    The single tyrosyl tRNA-synthetase (TyrRS) gene in trypanosomatid genomes codes for a protein that is twice the length of TyrRS from virtually all other organisms. Each half of the double-length TyrRS contains a catalytic domain and an anticodon-binding domain, however the two halves retain only 17% sequence identity to each other. The structural and functional consequences of this duplication and divergence are unclear. TyrRS normally forms a homodimer in which the active site of one monomer pairs with the anticodon-binding domain from the other. However, crystal structures of Leishmania major TyrRS show that instead the two halves of a single molecule form a pseudo-dimer resembling the canonical TyrRS dimer. Curiously, the C-terminal copy of the catalytic domain has lost the catalytically important HIGH and KMSKS motifs characteristic of Class I aminoacyl-tRNA synthetases. Thus the pseudo-dimer contains only one functional active site, contributed by the N-terminal half, and only one functional anticodon recognition site, contributed by the C-terminal half. Despite biochemical evidence for negative cooperativity between the two active sites of the usual TyrRS homodimer, previous structures have captured a crystallographically-imposed symmetric state. As the L. major TyrRS pseudo-dimer is inherently asymmetric, conformational variations observed near the active site may be relevant to understanding how the state of a single active site is communicated across the dimer interface. Furthermore, substantial differences between trypanosomal TyrRS and human homologs are promising for the design of inhibitors that selectively target the parasite enzyme. PMID:21420975

  18. A novel apolipoprotein C-II mimetic peptide that activates lipoprotein lipase and decreases serum triglycerides in apolipoprotein E-knockout mice.

    PubMed

    Amar, Marcelo J A; Sakurai, Toshihiro; Sakurai-Ikuta, Akiko; Sviridov, Denis; Freeman, Lita; Ahsan, Lusana; Remaley, Alan T

    2015-02-01

    Apolipoprotein A-I (apoA-I) mimetic peptides are currently being developed as possible new agents for the treatment of cardiovascular disease based on their ability to promote cholesterol efflux and their other beneficial antiatherogenic properties. Many of these peptides, however, have been reported to cause transient hypertriglyceridemia due to inhibition of lipolysis by lipoprotein lipase (LPL). We describe a novel bihelical amphipathic peptide (C-II-a) that contains an amphipathic helix (18A) for binding to lipoproteins and stimulating cholesterol efflux as well as a motif based on the last helix of apolipoprotein C-II (apoC-II) that activates lipolysis by LPL. The C-II-a peptide promoted cholesterol efflux from ATP-binding cassette transporter ABCA1-transfected BHK cells similar to apoA-I mimetic peptides. Furthermore, it was shown in vitro to be comparable to the full-length apoC-II protein in activating lipolysis by LPL. When added to serum from a patient with apoC-II deficiency, it restored normal levels of LPL-induced lipolysis and also enhanced lipolysis in serum from patients with type IV and V hypertriglyceridemia. Intravenous injection of C-II-a (30 mg/kg) in apolipoprotein E-knockout mice resulted in a significant reduction of plasma cholesterol and triglycerides of 38 ± 6% and 85 ± 7%, respectively, at 4 hours. When coinjected with the 5A peptide (60 mg/kg), the C-II-a (30 mg/kg) peptide was found to completely block the hypertriglyceridemic effect of the 5A peptide in C57Bl/6 mice. In summary, C-II-a is a novel peptide based on apoC-II, which promotes cholesterol efflux and lipolysis and may therefore be useful for the treatment of apoC-II deficiency and other forms of hypertriglyceridemia. U.S. Government work not protected by U.S. copyright.

  19. A Phytophthora sojae effector PsCRN63 forms homo-/hetero-dimers to suppress plant immunity via an inverted association manner

    PubMed Central

    Li, Qi; Zhang, Meixiang; Shen, Danyu; Liu, Tingli; Chen, Yanyu; Zhou, Jian-Min; Dou, Daolong

    2016-01-01

    Oomycete pathogens produce a large number of effectors to promote infection. Their mode of action are largely unknown. Here we show that a Phytophthora sojae effector, PsCRN63, suppresses flg22-induced expression of FRK1 gene, a molecular marker in pathogen-associated molecular patterns (PAMP)-triggered immunity (PTI). However, PsCRN63 does not suppress upstream signaling events including flg22-induced MAPK activation and BIK1 phosphorylation, indicating that it acts downstream of MAPK cascades. The PsCRN63-transgenic Arabidopsis plants showed increased susceptibility to bacterial pathogen Pseudomonas syringae pathovar tomato (Pst) DC3000 and oomycete pathogen Phytophthora capsici. The callose deposition were suppressed in PsCRN63-transgenic plants compared with the wild-type control plants. Genes involved in PTI were also down-regulated in PsCRN63-transgenic plants. Interestingly, we found that PsCRN63 forms an dimer that is mediated by inter-molecular interactions between N-terminal and C-terminal domains in an inverted association manner. Furthermore, the N-terminal and C-terminal domains required for the dimerization are widely conserved among CRN effectors, suggesting that homo-/hetero-dimerization of Phytophthora CRN effectors is required to exert biological functions. Indeed, the dimerization was required for PTI suppression and cell death-induction activities of PsCRN63. PMID:27243217

  20. Association of apolipoprotein E (ApoE) polymorphisms with risk of primary hyperuricemia in Uygur men, Xinjiang, China.

    PubMed

    Sun, Yu-Ping; Zhang, Bei; Miao, Lei; Wang, Xian-Min; Yu, Jia-Hui; Luo, Li; Ying, Lu; Xin, Gao; Haliakpaer, Gulinizha; Xia, He; Yao, Hua

    2015-04-12

    Apolipoprotein E (ApoE) participates in lipoprotein metabolism and immune regulation. This study assessed association between ApoE polymorphisms with hyperuricemia and uric acid metabolism in Uygur men, Xinjiang, China. A total of 474 hyperuricemia patients and 518 healthy male controls were recruited from the Health Screening Center, Uygur region of Xinjiang, China and subjected to ApoE genotyping using a multiplex amplification refractory mutation system PCR. Apolipoprotein E3/3 genotype was the predominant type with a frequency of 67.7%, while E2/2 was lower than E4/4 in Uygur males. The frequencies of ApoE2, E3, and E4 alleles were 8.5%, 80.1% and 11.4%, respectively. Distribution of ApoE genotypes was significantly different in hyperuricemia patients from the healthy controls (p<0.001). Particularly, the frequency of ApoE E3/3 was 71.7%, E2/3 9.3%, E3/4 9.3%, E4/4 3.2%, E2/4 2.3%, and E2/2 0.2% in patients vs. 68.1%, 4.6%, 2.9%, 12%, 0.6%, and 4.6% in controls, respectively. Moreover, frequency of ApoE E2 allele was greater in the healthy controls than in patients (p<0.001) and the highest level of uric acid occurred in those with ApoE2/4 and E3/4 genotypes, whereas the lowest uric acid level occurred in those with ApoE E2/2 genotype. In addition, the subjects with the ApoE2 allele had a lower uric acid and LDL-C level than those with the ApoE3 allele and ApoE4 allele (p<0.05). The risk of developing hyperuricemia in subjects without the ApoE2 allele was 1.7 fold higher than those subjects with the ApoE2 allele. This study revealed frequencies and distributions of ApoE alleles and genotypes in Uygur males, which are different from Han Chinese. ApoE E4 was associated with a slightly higher risk of primary hyperuricemia, whereas ApoE E2 was associated with reduced risk of primary hyperuricemia and LDL-C level.

  1. Apolipoprotein E inhibits osteoclast differentiation via regulation of c-Fos, NFATc1 and NF-κB

    SciTech Connect

    Kim, Woo-Shin; Kim, Hyung Joon; Lee, Zang Hee; Lee, Youngkyun; Kim, Hong-Hee

    2013-02-15

    Apolipoprotein E (ApoE) plays a major role in the transport and metabolism of lipid. Other functions of ApoE include modulation of innate and adaptive immune responses. The expression of ApoE in osteoblasts and its relevance with bone formation have also been reported. However, the effect of ApoE on osteoclasts has not yet been examined. Here, we investigated the role of ApoE in osteoclast differentiation using bone marrow-derived macrophages (BMMs) and RAW264.7 cells. We found a down-regulation of ApoE gene expression during osteoclastic differentiation of those cells. Overexpression of ApoE in BMMs and RAW264.7 cells significantly blocked the induction of c-Fos and nuclear factor of activated T cell c1 (NFATc1), transcription factors critical for expression of osteoclast marker genes, by receptor activator of nuclear factor κB ligand (RANKL), the osteoclast differentiation factor. ApoE inhibited osteoclast differentiation, as measured by decreased number of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells (MNCs). In addition, ApoE reduced the expression of dendritic cell-specific transmembrane protein (DC-STAMP) and ATPase, H{sup +} transporting, lysosomal 38 kDa, V0 subunit d2 (ATP6v0d2), genes involved in cell–cell fusion during osteoclastogenesis. Knock-down of ApoE using a specific siRNA promoted the RANKL-mediated induction of osteoclast differentiation. While ApoE did not affect the activation of ERK, JNK, and p38 MAPK signaling pathways by RANKL, the phosphorylation of p65 trans-activation domain on serine 536 and transcription activity of NF-κB were reduced by ApoE overexpression. These findings suggest that ApoE plays an inhibitory role in osteoclast differentiation via the suppression of RANKL-dependent activation of NF-κB and induction of c-Fos and NFATc1. - Highlights: ► Apolipoprotein E (ApoE) significantly inhibited osteoclast differentiation and activation of NF-κB. ► ApoE decreased the induction of osteoclast marker

  2. Apolipoprotein E-knockout mice on high-fat diet show autoimmune injury on kidney and aorta

    SciTech Connect

    Wang, Yuehai; Lu, Huixia; Huang, Ziyang; Lin, Huili; Lei, Zhenmin; Tang, Mengxiong; Gao, Fei; Dong, Mei; Li, Rongda; Lin, Ling

    2014-07-18

    Highlights: • Titers of ANA and anti-dsDNA antibodies were similar in ApoE{sup −/−} and Fas{sup −/−} mice. • The spleen weights and glomerular areas were similar in ApoE{sup −/−} and Fas{sup −/−} mice. • Expressions of IgG and C3 in glomeruli were similar in ApoE{sup −/−} and Fas{sup −/−} mice. • IgG, C3 and macrophage infiltration in aortic plaques were found in ApoE{sup −/−} mice. - Abstract: Background: Apolipoprotein E-knockout (ApoE{sup −/−}) mice is a classic model of atherosclerosis. We have found that ApoE{sup −/−} mice showed splenomegaly, higher titers of serum anti-nuclear antibody (ANA) and anti-dsDNA antibody compared with C57B6/L (B6) mice. However, whether ApoE{sup −/−} mice show autoimmune injury remains unclear. Methods and results: Six females and six males in each group, ApoE{sup −/−}, Fas{sup −/−} and B6 mice, were used in this study. The titers of serum ANA, anti-dsDNA antibody and creatinine and urine protein were measured by ELISA after 4 months of high-fat diet. The spleen weight and the glomerular area were determined. The expressions of IgG, C3 and macrophage in kidney and atherosclerotic plaque were detected by immunostaining followed by morphometric analysis. Similar to the characteristics of Fas{sup −/−} mice, a model of systemic lupus erythematosus (SLE), ApoE{sup −/−} mice, especially female, displayed significant increases of spleen weight and glomerular area when compared to B6 mice. Also, elevated titers of serum ANA, anti-dsDNA antibody and creatinine and urine protein. Moreover, the expressions of IgG, C3 and macrophage in glomeruli and aortic plaques were found in ApoE{sup −/−} mice. In addition, the IgG and C3 expressions in glomeruli and plaques significantly increased (or a trend of increase) in female ApoE{sup −/−} mice compared with males. Conclusions: Apolipoprotein E-knockout mice on high-fat diet show autoimmune injury on kidney and aorta.

  3. ClC-1 and ClC-2 form hetero-dimeric channels with novel protopore functions.

    PubMed

    Stölting, Gabriel; Fischer, Martin; Fahlke, Christoph

    2014-12-01

    CLC-type chloride channels exhibit a unique double-barreled architecture with two independently functioning ion conduction pathways, the so-called protopores. There exist gating processes that open and close individual protopores as well as common processes that jointly mediate slow opening and closing of both protopores. Different isoforms exhibit distinct voltage dependences and kinetics of gating. Whereas opening of the individual and common gate of homo-dimeric ClC-1 is promoted by membrane depolarization, ClC-2 is closed at positive potentials and opens only at negative voltages. To characterize the functional interaction of protopores we engineered a concatameric construct linking the coding regions of ClC-1 and ClC-2 in an open reading frame, expressed it in mammalian cells and measured anion currents through whole-cell and single channel patch clamping. In the hetero-dimeric assembly, each protopore displayed two kinetically distinct gating processes. Fast gating of the ClC-1 protopore closely resembled fast protopore gating of homo-dimeric channels. The voltage dependence of ClC-2 fast gating was shifted to more positive potentials by the adjacent ClC-1 protopore, resulting in open ClC-2 protopores at positive voltages. We observed two slow gating processes individually acting on ClC-1 and ClC-2 protopores, with distinct time and voltage dependences. Single channel recordings demonstrated that hetero-dimerization additionally modified the unitary conductance of ClC-2 protopores. Our findings suggest that inter-subunit interactions do not only affect common gating, but also ion permeation and gating of individual protopores in hetero-dimeric ClC channels.

  4. Apolipoprotein E (ApoE) polymorphism is related to differences in potential fertility in women: a case of antagonistic pleiotropy?

    PubMed

    Jasienska, Grazyna; Ellison, Peter T; Galbarczyk, Andrzej; Jasienski, Michal; Kalemba-Drozdz, Malgorzata; Kapiszewska, Maria; Nenko, Ilona; Thune, Inger; Ziomkiewicz, Anna

    2015-03-22

    The alleles that are detrimental to health, especially in older age, are thought to persist in populations because they also confer some benefits for individuals (through antagonistic pleiotropy). The ApoE4 allele at the ApoE locus, encoding apolipoprotein E (ApoE), significantly increases risk of poor health, and yet it is present in many populations at relatively high frequencies. Why has it not been replaced by natural selection with the health-beneficial ApoE3 allele? ApoE is a major supplier of cholesterol precursor for the production of ovarian oestrogen and progesterone, thus ApoE has been suggested as the potential candidate gene that may cause variation in reproductive performance. Our results support this hypothesis showing that in 117 regularly menstruating women those with genotypes with at least one ApoE4 allele had significantly higher levels of mean luteal progesterone (144.21 pmol l(-1)) than women with genotypes without ApoE4 (120.49 pmol l(-1)), which indicates higher potential fertility. The hormonal profiles were based on daily data for entire menstrual cycles. We suggest that the finding of higher progesterone in women with ApoE4 allele could provide first strong evidence for an evolutionary mechanism of maintaining the ancestral and health-worsening ApoE4 allele in human populations.

  5. Apolipoprotein E (ApoE) polymorphism is related to differences in potential fertility in women: a case of antagonistic pleiotropy?

    PubMed Central

    Jasienska, Grazyna; Ellison, Peter T.; Galbarczyk, Andrzej; Jasienski, Michal; Kalemba-Drozdz, Malgorzata; Kapiszewska, Maria; Nenko, Ilona; Thune, Inger; Ziomkiewicz, Anna

    2015-01-01

    The alleles that are detrimental to health, especially in older age, are thought to persist in populations because they also confer some benefits for individuals (through antagonistic pleiotropy). The ApoE4 allele at the ApoE locus, encoding apolipoprotein E (ApoE), significantly increases risk of poor health, and yet it is present in many populations at relatively high frequencies. Why has it not been replaced by natural selection with the health-beneficial ApoE3 allele? ApoE is a major supplier of cholesterol precursor for the production of ovarian oestrogen and progesterone, thus ApoE has been suggested as the potential candidate gene that may cause variation in reproductive performance. Our results support this hypothesis showing that in 117 regularly menstruating women those with genotypes with at least one ApoE4 allele had significantly higher levels of mean luteal progesterone (144.21 pmol l−1) than women with genotypes without ApoE4 (120.49 pmol l−1), which indicates higher potential fertility. The hormonal profiles were based on daily data for entire menstrual cycles. We suggest that the finding of higher progesterone in women with ApoE4 allele could provide first strong evidence for an evolutionary mechanism of maintaining the ancestral and health-worsening ApoE4 allele in human populations. PMID:25673673

  6. Demographic and Lifestyle Characteristics, but Not Apolipoprotein E Genotype, Are Associated with Intelligence among Young Chinese College Students.

    PubMed

    Chen, Xiao-Fen; Wei, Zichen; Wang, Tingting; Zhang, Zhen-Lian; Wang, Yiwei; Heckman, Michael G; Diehl, Nancy N; Zhang, Yun-Wu; Xu, Huaxi; Bu, Guojun

    2015-01-01

    Intelligence is an important human feature that strongly affects many life outcomes, including health, life-span, income, educational and occupational attainments. People at all ages differ in their intelligence but the origins of these differences are much debated. A variety of environmental and genetic factors have been reported to be associated with individual intelligence, yet their nature and contribution to intelligence differences have been controversial. To investigate the contribution of apolipoprotein E (APOE) genotype, which is associated with the risk for Alzheimer's disease, as well as demographic and lifestyle characteristics, to the variation in intelligence. A total of 607 Chinese college students aged 18 to 25 years old were included in this prospective observational study. The Chinese revision of Wechsler Adult Intelligence Scale (the fourth edition, short version) was used to determine the intelligence level of participants. Demographic and lifestyle characteristics data were obtained from self-administered questionnaires. No significant association was found between APOE polymorphic alleles and different intelligence quotient (IQ) measures. Interestingly, a portion of demographic and lifestyle characteristics, including age, smoking and sleep quality were significantly associated with different IQ measures. Our findings indicate that demographic features and lifestyle characteristics, but not APOE genotype, are associated with intelligence measures among young Chinese college students. Thus, although APOE ε4 allele is a strong genetic risk factor for Alzheimer's disease, it does not seem to impact intelligence at young ages.

  7. The Apolipoprotein E Polymorphism rs7412 Associates with Body Fatness Independently of Plasma Lipids in Middle Aged Men

    PubMed Central

    Tejedor, M. Teresa; Garcia-Sobreviela, Maria Pilar; Ledesma, Marta; Arbones-Mainar, Jose M.

    2014-01-01

    Background The apolipoprotein E (APOE) gene is polymorphic, encoding one of 3 common alleles (ε2, ε3, ε4) produced from combinations of 2 non-synonymous SNPs (rs429358 and rs7412). APOE plays an important role controlling plasma lipids but its association with adipocyte functionality and body fatness remains to be determined. Methods We analyzed fasting plasma lipids and genotyped the two main APOE-SNPs (rs429358 and rs7412), both located in the fourth exon of the APOE, in 4660 Caucasian middle-aged men free of cardiovascular disease. Results The rs7412 SNP, which determines the APOE2 isoform, was significantly associated with Body Mass Index (BMI) and Waist Girth (WG) in a multivariate model accounting for age, smoking status and plasma lipids. BMI and WG were highest in TT homozygotes and lowest in CC homozygotes. This effect was independent of the rs429358 SNP, which failed to show any association with the BMI and WG variables. The odds ratio of being obese (BMI>30) for individuals carrying the APOε2 allele, present in 14% of the cohort and defined by the rs7412 SNP, was also significant in this multivariate model, with an OR of 1.27 (95% CI: 1.01–1.59). Conclusions This study provides an evidence of a lipid-independent association between the APOE SNP rs7412 and body fatness surrogates, BMI and WG, in a large cohort of middle-aged males. PMID:25268647

  8. Association of apolipoprotein E genotypes, blood pressure, blood lipids and ECG abnormalities in a general population aged 85+

    PubMed Central

    Rastas, Sari; Mattila, Kimmo; Verkkoniemi, Auli; Niinistö, Leena; Juva, Kati; Sulkava, Raimo; Länsimies, Esko

    2004-01-01

    Background Several studies have linked apolipoprotein E (ApoE) ε4 allele with elevated cholesterol and blood pressure levels. Data on the association of APOE genotypes with blood pressure, lipids, atrial fibrillation and ECG abnormalities in individuals aged 85 years and over is sparse. Methods This cross sectional study consisted of all residents of the city of Vantaa (N = 601) aged 85 years or over of whom 505 participated in the study. Blood pressure was measured by using mercury sphygmomanometer. 12-Lead ECG, short ambulatory ECG, or both were taken from all study subjects to diagnose atrial fibrillation (AF). Ambulatory ECG was carried out home or in the institute. APOE genotyping was performed using a combination of the polymerase chain reaction (PCR) and solid-phase minisequencing technique. Statistical analysis was made by using Kruskall-Wallis-test (continuous data) and χ2-test (rates and proportions). Results In these very elderly individuals, APOE 4 allele was significantly associated with elevated cholesterol and low-density lipoprotein (LDL) levels. Blood pressure or cardiac arrhythmias did not differ between APOE genotypes. Conclusions These observations suggest that the important role of APOE genotype still influences cardiovascular risk profile even among the very elderly people. PMID:15050032

  9. Association of apolipoprotein E genotypes, blood pressure, blood lipids and ECG abnormalities in a general population aged 85+.

    PubMed

    Rastas, Sari; Mattila, Kimmo; Verkkoniemi, Auli; Niinistö, Leena; Juva, Kati; Sulkava, Raimo; Länsimies, Esko

    2004-03-29

    Several studies have linked apolipoprotein E (ApoE) epsilon4 allele with elevated cholesterol and blood pressure levels. Data on the association of APOE genotypes with blood pressure, lipids, atrial fibrillation and ECG abnormalities in individuals aged 85 years and over is sparse. This cross sectional study consisted of all residents of the city of Vantaa (N = 601) aged 85 years or over of whom 505 participated in the study. Blood pressure was measured by using mercury sphygmomanometer. 12-Lead ECG, short ambulatory ECG, or both were taken from all study subjects to diagnose atrial fibrillation (AF). Ambulatory ECG was carried out home or in the institute. APOE genotyping was performed using a combination of the polymerase chain reaction (PCR) and solid-phase minisequencing technique. Statistical analysis was made by using Kruskall-Wallis-test (continuous data) and chi2-test (rates and proportions). In these very elderly individuals, APOE 4 allele was significantly associated with elevated cholesterol and low-density lipoprotein (LDL) levels. Blood pressure or cardiac arrhythmias did not differ between APOE genotypes. These observations suggest that the important role of APOE genotype still influences cardiovascular risk profile even among the very elderly people.

  10. Site-specific dephosphorylation of tau of apolipoprotein E-deficient and control mice by M1 muscarinic agonist treatment.

    PubMed

    Genis, I; Fisher, A; Michaelson, D M

    1999-01-01

    Apolipoprotein E (apoE)-deficient mice have memory deficits that are associated with synaptic loss of basal forebrain cholinergic projections and with hyperphosphorylation of distinct epitopes of the microtubule-associated protein tau. Furthermore, treatment of apoE-deficient mice with the M1 selective agonist 1-methylpiperidine-4-spiro-(2'-methylthiazoline) [AF150(S)] abolishes their memory deficits and results in recovery of their brain cholinergic markers. In the present study, we used a panel of anti-tau monoclonal antibodies to further map the tau epitopes that are hyperphosphorylated in apoE-deficient mice and examined the effects of prolonged treatment with AF150(S). This revealed that tau of apoE-deficient mice contains a distinct, hyperphosphorylated "hot spot" domain which is localized N-terminally to the microtubule binding domain of tau, and that AF150(S) has an epitope-specific tau dephosphorylating effect whose magnitude is affected by apoE deficiency. Accordingly, epitopes which reside in the hyperphosphorylated "hot spot" are dephosphorylated by AF150(S) in apoE-deficient mice but are almost unaffected in the controls, whereas epitopes which flank this tau domain are dephosphorylated by AF150(S) in both mice groups. In contrast, epitopes located at the N and C terminals of tau are unaffected by AF150(S) in both groups of mice. These findings suggest that apoE deficiency results in hyperphosphorylation of a distinct tau domain whose excess phosphorylation can be reduced by muscarinic treatment.

  11. Angiopoietin-2 attenuates angiotensin II-induced aortic aneurysm and atherosclerosis in apolipoprotein E-deficient mice

    PubMed Central

    Yu, Hongyou; Moran, Corey S.; Trollope, Alexandra F.; Woodward, Lynn; Kinobe, Robert; Rush, Catherine M.; Golledge, Jonathan

    2016-01-01

    Angiogenesis and inflammation are implicated in aortic aneurysm and atherosclerosis and regulated by angiopoietin-2 (Angpt2). The effect of Angpt2 administration on experimental aortic aneurysm and atherosclerosis was examined. Six-month-old male apolipoprotein E deficient (ApoE−/−) mice were infused with angiotensin II (AngII) and administered subcutaneous human Fc-protein (control) or recombinant Angpt2 (rAngpt2) over 14 days. Administration of rAngpt2 significantly inhibited AngII-induced aortic dilatation and rupture of the suprarenal aorta (SRA), and development of atherosclerosis within the aortic arch. These effects were blood pressure and plasma lipoprotein independent and associated with Tie2 activation and down-regulation of monocyte chemotactic protein-1 (MCP-1) within the SRA. Plasma concentrations of MCP-1 and interleukin-6 were significantly lower in mice receiving rAngpt2. Immunostaining for the monocyte/macrophage marker MOMA-2 and the angiogenesis marker CD31 within the SRA were less in mice receiving rAngpt2 than controls. The percentage of inflammatory (Ly6Chi) monocytes within the bone marrow was increased while that in peripheral blood was decreased by rAngpt2 administration. In conclusion, administration of rAngpt2 attenuated angiotensin II-induced aortic aneurysm and atherosclerosis in ApoE−/− mice associated with reduced aortic inflammation and angiogenesis. Up-regulation of Angpt2 may have potential therapeutic value in patients with aortic aneurysm and atherosclerosis. PMID:27767064

  12. Apolipoprotein E genotype and plasma levels in coronary artery disease. A case-control study in the Italian population.

    PubMed

    Corbo, R M; Vilardo, T; Ruggeri, M; Gemma, A T; Scacchi, R

    1999-04-01

    To investigate the role of the apolipoprotein B and apolipoprotein E polymorphisms in coronary artery disease (CAD) susceptibility in the Italian population and their relation to plasma lipid and apolipoprotein levels. APOB (APOB Xbal, EcoRI, Ins/Del), and APOE (APOE Cfol) polymorphisms were analyzed in 150 male CAD patients and 110 matched controls. In the same subjects plasma lipid, apoB, and apoE levels were measured. No differences in the distribution of the APOB polymorphisms were observed between patients and controls. Among patients the number of e*4-carriers was significantly higher than in controls. e*4-carriers were more frequent among the hypertensive patients and had a higher systolic blood pressure (p = 0.007) than the non-e*4 carriers. The APOB Xbal polymorphism was found to influence the distribution of HDL-cholesterol. Patients showed significantly lower levels of apoE (39.29 mg/L) than controls (54.32 mg/dL) and the lowest concentrations were associated to the E4/E3 and E4/E4 genotypes. Quantitative data are consistent with the hypothesis that apoE has an anti-atherosclerotic role and suggest that the apoE quantitation could be a useful parameter for defining cardiovascular risk. e*4 allele appears to be a risk factor for CAD in the Italian population and could act by its association with low apoE levels.

  13. Herpes simplex virus type 1 infection via the bloodstream with apolipoprotein E dependence in the gonads is influenced by gender.

    PubMed

    Burgos, Javier S; Ramirez, Carlos; Sastre, Isabel; Alfaro, Juan M; Valdivieso, Fernando

    2005-02-01

    Herpes simplex virus type 1 (HSV-1) causes disease in humans and animals. Infection usually occurs via the neural route and possibly occurs via the hematogenous route. The latter, however, is the main route by which immunosuppressed individuals and neonates are infected. Gender-dependent differences in the incidence and severity of some viral infections have been reported. To detect differences between the sexes with respect to HSV-1 colonization and disease, the characteristics of both acute and latent infections in hematogenously infected male and female mice were compared. In acute infection, the female mice had a poorer outcome: HSV-1 colonization was more effective, especially in the gonads and brain. In the encephalon, the midbrain had the highest viral load. In latent infection, brain viral loads were not significantly different with respect to sex. Significant differences were seen, however, in the blood and trigeminal ganglia: HSV-1 seroprevalence was observed in females, with no virus detected in males. In brain dissections, only the cerebral cortex of the females had viral loads statistically higher than those observed in the males. The spread of the virus to several organs of interest during acute infection was examined immunohistochemically. Female mice showed greater viral immunostaining, especially in the adrenal cortex, gonads, and midbrain. In male mice, HSV-1 was detected predominantly in the adrenal cortex. It was also found that apolipoprotein E promotes virus colonization of the ovaries, the APOE gene dose being directly related to viral invasiveness.

  14. Cigarette smoke enhances abdominal aortic aneurysm formation in angiotensin II-treated apolipoprotein E-deficient mice.

    PubMed

    Stolle, Katrin; Berges, An; Lietz, Michael; Lebrun, Stefan; Wallerath, Thomas

    2010-12-15

    Cigarette smoke, hyperlipidemia, and hypertension with the risk of development and progression of atherosclerosis and associated pathologies such as abdominal aortic aneurysm (AAA) are correlated. We examined the interaction of cigarette mainstream smoke (MS) and angiotensin-II (Ang II)-induced hypertension in the atherosclerotic process using hyperlipidemic apolipoprotein E-knockout (ApoE(-/-)) mice. ApoE(-/-) mice were treated with Ang II for 4 weeks and then further exposed to MS or to fresh air for 4 weeks. AAA formation was observed in all mice treated with Ang II, regardless of smoke exposure; however, smoke exposure increased the incidence of AAA in these mice. Ang II treatment resulted in higher gene expression of matrix metalloproteinases (MMP)-2, -3, -8, -9, and -12 in the abdominal aortas, which was further increased by MS exposure. The proteolytic activity of MMP-2 and MMP-9 was also enhanced in Ang II-treated mice exposed to MS, but only minor changes were seen with either smoke exposure or Ang II treatment alone. This study shows for the first time that both formation and severity of AAA in hypertensive ApoE(-/-) mice are accelerated by exposure to MS and that the proteolytic activity of MMPs is enhanced by the combination of Ang II and MS. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  15. Protease-Activated Receptor-2 Deficiency Attenuates Atherosclerotic Lesion Progression and Instability in Apolipoprotein E-Deficient Mice.

    PubMed

    Zuo, Pengfei; Zuo, Zhi; Zheng, Yueyue; Wang, Xin; Zhou, Qianxing; Chen, Long; Ma, Genshan

    2017-01-01

    Inflammatory mechanisms are involved in the process of atherosclerotic plaque formation and rupture. Accumulating evidence suggests that protease-activated receptor (PAR)-2 contributes to the pathophysiology of chronic inflammation on the vasculature. To directly examine the role of PAR-2 in atherosclerosis, we generated apolipoprotein E/PAR-2 double-deficient mice. Mice were fed with high-fat diet for 12 weeks starting at ages of 6 weeks. PAR-2 deficiency attenuated atherosclerotic lesion progression with reduced total lesion area, reduced percentage of stenosis and reduced total necrotic core area. PAR-2 deficiency increased fibrous cap thickness and collagen content of plaque. Moreover, PAR-2 deficiency decreased smooth muscle cell content, macrophage accumulation, matrix metallopeptidase-9 expression and neovascularization in plaque. Relative quantitative PCR assay using thoracic aorta revealed that PAR-2 deficiency reduced mRNA expression of inflammatory molecules, such as vascular cell adhesion molecule-1, intercellular adhesion molecule-1, tumor necrosis factor (TNF)-α and monocyte chemoattractant protein (MCP)-1. In vitro experiment, we found that PAR-2 deficiency reduced mRNA expression of interferon-γ, interleukin-6, TNF-α and MCP-1 in macrophage under unstimulated and lipopolysaccharide-stimulated conditions. These results suggest that PAR-2 deficiency attenuates the progression and instability of atherosclerotic plaque.

  16. Spatial Pattern Separation Differences in Older Adult Carriers and Non-Carriers for the Apolipoprotein E Epsilon 4 Allele

    PubMed Central

    Sheppard, David P.; Graves, Lisa V.; Holden, Heather M.; Delano-Wood, Lisa; Bondi, Mark W.; Gilbert, Paul E.

    2015-01-01

    We examined the performance of healthy young (n=57) and older adults (n=43) genotyped as apolipoprotein E-ε4 (APOE-ε4) carriers or APOE-ε4 non-carriers on a delayed match-to-sample task involving varying degrees of spatial interference hypothesized to assess spatial pattern separation. Older adult ε4 carriers were further divided into “impaired” and “unimpaired” groups based on their performance on a standardized test of verbal memory. We found that performance on the spatial pattern separation test increased as a function of decreased spatial interference across all groups. The older ε4 carriers in the impaired group performed significantly worse (p < .05) than unimpaired ε4 carriers, ε4 non-carriers, and young adults. The data suggest that spatial pattern separation may be less efficient in a subset of healthy older adults with subtle memory decline who are carriers of the ε4 allele. However, pattern separation performance may be comparable to that of young adults in a subset of older adult ε4 carriers and more broadly among non-carriers. Our findings offer additional evidence that pattern separation may vary in older adults, and they provide novel insight into pattern separation efficiency in ε4-positive older adults. PMID:25957133

  17. Characterization of five new mutants in the carboxyl-terminal domain of human apolipoprotein E: No cosegregation with severe hyperlipidemia

    SciTech Connect

    Maagdenberg, A.M.J.M. van den; Bruijn, I.H. de; Hofker, M.H.; Frants, R.R. ); Knijff, P. de; Smelt, A.H.M.; Leuven, J.A.G.; van't Hooft, F.; Assmann, G.; Havekes, L.M. ); Weng, Wei; Funke, H. )

    1993-05-01

    Assessment of the apolipoprotein E (apoE) phenotype by isoelectric focusing of both hyperlipidemic and normolipidemic individuals identified five new variants. All mutations were confined to the downstream part of the APOE gene by using denaturing gradient gel electrophoresis (DGGE). Sequence analysis revealed five new mutations causing unique amino acid substitutions in the carboxyl-terminal part of the protein containing the putative lipid-binding domain. Three hyperlipoproteinemic probands were carriers of the APOE*2(Va1236[r arrow]Glu) allele, the APOE*3(Cys112-Arg; Arg251[r arrow]Gly) allele, or the APOE*1(Arg158[r arrow]Cys; Leu252[r arrow]Glu) allele. DGGE of the region encoding the receptor-binding domain was useful for haplotyping the mutations at codons 112 and 158. Family studies failed to demonstrate cosegregation between the new mutations and severe hyperlipoproteinemia, although a number of carriers for the APOE*3(Cys112[r arrow]Arg; Arg251[r arrow]Gly) allele and the APOE*1(Arg158-Cys; Leu252[r arrow]Glu) allele expressed hypertriglyceridemia and/ or hypercholesterolemia. Two other mutant alleles, APOE*4[sup [minus

  18. Apolipoprotein E polymorphism in elderly Japanese-Brazilian immigrants does not explain the reduced cardiovascular risk factor incidence.

    PubMed

    Terra, N; Moriguchi, Y; Bittencourt, L; Trois, R S; Piccoli, J E C; Cruz, I B M

    2011-09-09

    Study of immigrant populations may contribute to a better understanding of the epidemiology of diseases associated with the aging process. We examined the prevalence of cardiovascular risk factors, including apolipoprotein E (ApoE) polymorphism, in elderly subjects who were born in Japan, migrated to South Brazil and have lived in that region for over 40 years, versus a group of elderly, locally born Brazilians living in the same region. These Japanese subjects came to Brazil after World War II (1950-1960) from several Japanese cities, mainly Nagasaki, Kumamoto and Hokkaido. Among 1007 subjects genotyped for ApoE polymorphism, we selected 540 elderly subjects (>60 years old), consisting of 270 Japanese-Brazilians and 270 Brazilians of European ancestry from Rio Grande do Sul State (Gaucha population). The Japanese-Brazilian group had significantly lower prevalences of obesity, type 2 diabetes mellitus, dyslipidemia, and metabolic syndrome than did the Gaucho population group. ApoE polymorphism frequencies were similar in the two groups. The differences in cardiovascular risk factors observed in the two populations cannot be explained by ApoE polymorphism; they could be related to conservation of Japanese lifestyle habits, such as diet.

  19. Primary Genetic Investigation of a Hyperlipidemia Model: Molecular Characteristics and Variants of the Apolipoprotein E Gene in Mongolian Gerbil

    PubMed Central

    Liu, Yuehuan; Wu, Jiusheng; Shi, Qiaojuan; Guo, Honggang; Ying, Huazhong; Xu, Ningying

    2014-01-01

    The objective of this work was to establish a novel Mongolian gerbil (Meriones unguiculatus) hyperlipidemia model and to investigate its susceptibility genetic basis. Two rodent (gerbil and rat) hyperlipidemia models were induced by feeding a high fat/high-cholesterol (HF/HC) diet. There were significant increases of serum total cholesterol, triglycerides, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) in gerbils within a 4-week modeling period. About 10–30% of >8-month-old individuals developed hyperlipidemia spontaneously. The apolipoprotein E (ApoE) gene was cloned by merging a sequence of rapid amplification of cDNA ends (RACE) and nested polymerase chain reaction products. The results revealed an open reading frame of 948 bp, encoding a protein of 298 amino acids. The gene without a 5′-UTR region in the first intron was highly homologous to human Apo-A-I and rat Apo-A-IV. The distribution of expression of the ApoE gene in liver, brain, heart, lung, kidney, and adrenal gland was detected by an ABC immunohistochemical procedure. Three single nucleotide polymorphisms (SNPs; C97T, G781T, and A1774T) were first found using PCR-single-strand conformation polymorphism (PCR-SSCP) in a closed population containing 444 animals. Correlation analysis confirmed that new SNPs , age, and gender were associated significantly (P < 0.05) with hyperlipidemia. PMID:25006576

  20. Accelerated pericyte degeneration and blood–brain barrier breakdown in apolipoprotein E4 carriers with Alzheimer’s disease

    PubMed Central

    Halliday, Matthew R; Rege, Sanket V; Ma, Qingyi; Zhao, Zhen; Miller, Carol A; Winkler, Ethan A

    2016-01-01

    The blood–brain barrier (BBB) limits the entry of neurotoxic blood-derived products and cells into the brain that is required for normal neuronal functioning and information processing. Pericytes maintain the integrity of the BBB and degenerate in Alzheimer’s disease (AD). The BBB is damaged in AD, particularly in individuals carrying apolipoprotein E4 (APOE4) gene, which is a major genetic risk factor for late-onset AD. The mechanisms underlying the BBB breakdown in AD remain, however, elusive. Here, we show accelerated pericyte degeneration in AD APOE4 carriers >AD APOE3 carriers >non-AD controls, which correlates with the magnitude of BBB breakdown to immunoglobulin G and fibrin. We also show accumulation of the proinflammatory cytokine cyclophilin A (CypA) and matrix metalloproteinase-9 (MMP-9) in pericytes and endothelial cells in AD (APOE4 >APOE3), previously shown to lead to BBB breakdown in transgenic APOE4 mice. The levels of the apoE lipoprotein receptor, low-density lipoprotein receptor-related protein-1 (LRP1), were similarly reduced in AD APOE4 and APOE3 carriers. Our data suggest that APOE4 leads to accelerated pericyte loss and enhanced activation of LRP1-dependent CypA–MMP-9 BBB-degrading pathway in pericytes and endothelial cells, which can mediate a greater BBB damage in AD APOE4 compared with AD APOE3 carriers. PMID:25757756

  1. The apolipoprotein E polymorphism rs7412 associates with body fatness independently of plasma lipids in middle aged men.

    PubMed

    Tejedor, M Teresa; Garcia-Sobreviela, Maria Pilar; Ledesma, Marta; Arbones-Mainar, Jose M

    2014-01-01

    The apolipoprotein E (APOE) gene is polymorphic, encoding one of 3 common alleles (ε2, ε3, ε4) produced from combinations of 2 non-synonymous SNPs (rs429358 and rs7412). APOE plays an important role controlling plasma lipids but its association with adipocyte functionality and body fatness remains to be determined. We analyzed fasting plasma lipids and genotyped the two main APOE-SNPs (rs429358 and rs7412), both located in the fourth exon of the APOE, in 4660 Caucasian middle-aged men free of cardiovascular disease. The rs7412 SNP, which determines the APOE2 isoform, was significantly associated with Body Mass Index (BMI) and Waist Girth (WG) in a multivariate model accounting for age, smoking status and plasma lipids. BMI and WG were highest in TT homozygotes and lowest in CC homozygotes. This effect was independent of the rs429358 SNP, which failed to show any association with the BMI and WG variables. The odds ratio of being obese (BMI>30) for individuals carrying the APOε2 allele, present in 14% of the cohort and defined by the rs7412 SNP, was also significant in this multivariate model, with an OR of 1.27 (95% CI: 1.01-1.59). This study provides an evidence of a lipid-independent association between the APOE SNP rs7412 and body fatness surrogates, BMI and WG, in a large cohort of middle-aged males.

  2. Nicotine Accelerates Atherosclerosis in Apolipoprotein E-Deficient Mice by Activating α7 Nicotinic Acetylcholine Receptor on Mast Cells.

    PubMed

    Wang, Chen; Chen, Han; Zhu, Wei; Xu, Yinchuan; Liu, Mingfei; Zhu, Lianlian; Yang, Fan; Zhang, Ling; Liu, Xianbao; Zhong, Zhiwei; Zhao, Jing; Jiang, Jun; Xiang, Meixiang; Yu, Hong; Hu, Xinyang; Lu, Hong; Wang, Jian'an

    2017-01-01

    Cigarette smoking is an independent risk factor for atherosclerosis. Nicotine, the addictive component of cigarettes, induces mast cell (MC) release and contributes to atherogenesis. The purpose of this study was to determine whether nicotine accelerates atherosclerosis through MC-mediated mechanisms and whether MC stabilizer prevents this pathological process. Nicotine administration increased the size of atherosclerotic lesions in apolipoprotein E-deficient (Apoe(-/-)) mice fed a fat-enriched diet. This was accompanied by enhanced intraplaque macrophage content and lipid deposition but reduced collagen and smooth muscle cell contents. MC deficiency in Apoe(-/-) mice (Apoe(-/-)Kit(W-sh/W-sh)) diminished nicotine-induced atherosclerosis. Nicotine activated bone marrow-derived MCs in vitro, which was inhibited by a MC stabilizer disodium cromoglycate or a nonselective nicotinic acetylcholine receptor blocker mecamylamine. Further investigation revealed that α7 nicotinic acetylcholine receptor was a target for nicotine activation in MCs. Nicotine did not change atherosclerotic lesion size of Apoe(-/-)Kit(W-sh/W-sh) mice reconstituted with MCs from Apoe(-/-)α7nAChR(-/-) animals. Activation of α7 nicotinic acetylcholine receptor on MCs is a mechanism by which nicotine enhances atherosclerosis. © 2016 American Heart Association, Inc.

  3. Human apolipoprotein E ɛ4 expression impairs cerebral vascularization and blood–brain barrier function in mice

    PubMed Central

    Alata, Wael; Ye, Yue; St-Amour, Isabelle; Vandal, Milène; Calon, Frédéric

    2015-01-01

    Human apolipoprotein E (APOE) exists in three isoforms ɛ2, ɛ3, and ɛ4, of which APOE4 is the main genetic risk factor of Alzheimer's disease (AD). As cerebrovascular defects are associated with AD, we tested whether APOE genotype has an impact on the integrity and function of the blood–brain barrier (BBB) in human APOE-targeted replacement mice. Using the quantitative in situ brain perfusion technique, we first found lower (13.0% and 17.0%) brain transport coefficient (Clup) of [3H]-diazepam in APOE4 mice at 4 and 12 months, compared with APOE2 and APOE3 mice, reflecting a decrease in cerebral vascularization. Accordingly, results from immunohistofluorescence experiments revealed a structurally reduced cerebral vascularization (26% and 38%) and thinner basement membranes (30% and 35%) in 12-month-old APOE4 mice compared with APOE2 and APOE3 mice, suggesting vascular atrophy. In addition, APOE4 mice displayed a 29% reduction in [3H]-d-glucose transport through the BBB compared with APOE2 mice without significant changes in the expression of its transporter GLUT1 in brain capillaries. However, an increase of 41.3% of receptor for advanced glycation end products (RAGE) was found in brain capillaries of 12-month-old APOE4 mice. In conclusion, profound divergences were observed between APOE genotypes at the cerebrovascular interface, suggesting that APOE4-induced BBB anomalies may contribute to AD development. PMID:25335802

  4. Low-density lipoprotein receptor represents an apolipoprotein E-independent pathway of Aβ uptake and degradation by astrocytes.

    PubMed

    Basak, Jacob M; Verghese, Philip B; Yoon, Hyejin; Kim, Jungsu; Holtzman, David M

    2012-04-20

    Accumulation of the amyloid β (Aβ) peptide within the brain is hypothesized to be one of the main causes underlying the pathogenic events that occur in Alzheimer disease (AD). Consequently, identifying pathways by which Aβ is cleared from the brain is crucial for better understanding of the disease pathogenesis and developing novel therapeutics. Cellular uptake and degradation by glial cells is one means by which Aβ may be cleared from the brain. In the current study, we demonstrate that modulating levels of the low-density lipoprotein receptor (LDLR), a cell surface receptor that regulates the amount of apolipoprotein E (apoE) in the brain, altered both the uptake and degradation of Aβ by astrocytes. Deletion of LDLR caused a decrease in Aβ uptake, whereas increasing LDLR levels significantly enhanced both the uptake and clearance of Aβ. Increasing LDLR levels also enhanced the cellular degradation of Aβ and facilitated the vesicular transport of Aβ to lysosomes. Despite the fact that LDLR regulated the uptake of apoE by astrocytes, we found that the effect of LDLR on Aβ uptake and clearance occurred in the absence of apoE. Finally, we provide evidence that Aβ can directly bind to LDLR, suggesting that an interaction between LDLR and Aβ could be responsible for LDLR-mediated Aβ uptake. Therefore, these results identify LDLR as a receptor that mediates Aβ uptake and clearance by astrocytes, and provide evidence that increasing glial LDLR levels may promote Aβ degradation within the brain.

  5. The effect of alcohol and tobacco consumption, and apolipoprotein E genotype, on the age of onset in Alzheimer's disease.

    PubMed

    Harwood, Dylan G; Kalechstein, Ari; Barker, Warren W; Strauman, Silvia; St George-Hyslop, Peter; Iglesias, Casandra; Loewenstein, David; Duara, Ranjan

    2010-05-01

    This study examined the association between a history of heavy alcohol use and smoking, presence of the apolipoprotein-E epsilon 4 allele (APOE epsilon4), and age of disease onset in a community dwelling sample of 685 Alzheimer's disease (AD) patients spanning three ethnic groups. Cross-sectional study of AD patients evaluated at a University-affiliated outpatient memory disorders clinic. A clinic-based cohort of white non-Hispanic (WNH; n = 397), white Hispanic (WH; n = 264), and African-American (AA; n = 24) patients diagnosed with possible or probable AD according to NINCDS-ADRDA diagnostic criteria. The age of onset of AD was obtained from a knowledgeable family member. All patients were assessed for APOE genotype. History of alcohol and tobacco consumption prior to the onset of dementia was obtained via an interview with the patient and the primary caregiver. A history of heavy drinking was defined as >2 drinks per day and a history of heavy smoking was defined as > or =1 pack per day. Presence of an APOE epsilon4 allele, a history of heavy drinking, or a history of heavy smoking were each associated with an earlier onset of AD by 2-3 years. Patients with all three risk factors were likely to be diagnosed with AD nearly 10 years earlier than those with none of the risk factors. The results suggest that APOE epsilon4 and heavy drinking and heavy smoking lower the age of onset for AD in an additive fashion.

  6. Maternal apolipoprotein E genotype as a potential risk factor for poor birth outcomes: The Bogalusa Heart Study

    PubMed Central

    Jacobs, Marni B.; Harville, Emily W.; Kelly, Tanika N.; Bazzano, Lydia A.; Chen, Wei

    2016-01-01

    Objective To assess the association between apolipoprotein E (apoE) genotype and preterm birth (PTB) and small for gestational age (SGA). Study Design ApoE phenotyping was performed on 680 women linked to 1 065 births. Allele frequencies were compared and PTB and SGA risk was estimated using log-binomial regression. Results The ε2 allele was more common in SGA births (p < 0.01). SGA risk was increased among ε2 carriers compared to genotype ε3/ε3, though associations were attenuated following adjustment for maternal age, education, race, smoking, and prenatal visits. Stronger associations were observed for term SGA (first birth: aRR = 1.78, 95% CI 1.06 – 2.98; any birth: aRR = 1.52, 95% CI 0.96 – 2.40) and among whites specifically (first: aRR = 2.88, 95% CI 1.45 – 5.69; any: aRR = 2.75, 95% CI 1.46 – 5.22). Conclusions Associations between maternal apoE genotype and SGA may represent decreased fetal growth in women with lower circulating cholesterol levels. PMID:26890557

  7. Proanthocyanidin Attenuation of Oxidative Stress and NF-κB Protects Apolipoprotein E-Deficient Mice against Diabetic Nephropathy

    PubMed Central

    Al-Malki, Abdulrahman L.; Sayed, Ahmed Amir Radwan; El Rabey, Haddad A.

    2013-01-01

    Hyperlipidemia and hyperglycemia result in oxidative stress and play a major role in the development of diabetic nephropathy (DN). We explored the effects of proanthocyanidin (PA) on the induction and progression of DN in apolipoprotein E-deficient mice. Diabetes Mellitus was induced in ten-week-old male apoE−/−mice using streptozotocin (STZ). Mice were fed with a high-fat diet in presence or absence of PA. PA treatment significantly reduced the high cholesterol levels, restored renal functions, and reduced albuminuria in the PA-treated diabetic mice compared with the diabetic untreated mice. In addition, the glomerular mesangial expansion in the diabetic mice was attenuated as a result of PA supplementation. Moreover, PA treatment restored the elevated levels of MDA and CML and the reduced activity of SOD and GSH in the diabetic mice. Furthermore, PA feeding reduced the activation and translocation of NF-κB to the nucleus compared with the diabetic untreated animals. Reduction of NF-κB activation resulted in the attenuation of the expression of IL-6, TGFβ, and RAGE which protected PA-treated mice against DN. The renoprotective effects of PA were found to be time independent regardless of whether the dietary feeding with PA was started pre-, co-, or post-STZ injection. In conclusion, part of the beneficial effects of PA includes the disruption of the detrimental AGE-RAGE-NFκB pathways. PMID:24023581

  8. Lactobacillus acidophilus ATCC 4356 Prevents Atherosclerosis via Inhibition of Intestinal Cholesterol Absorption in Apolipoprotein E-Knockout Mice

    PubMed Central

    Wang, Jinfeng; Quan, Guihua; Wang, Xiaojun; Yang, Longfei; Zhong, Lili

    2014-01-01

    The objective of this study was to investigate the effect of Lactobacillus acidophilus ATCC 4356 on the development of atherosclerosis in apolipoprotein E-knockout (ApoE−/−) mice. Eight-week-old ApoE−/− mice were fed a Western diet with or without L. acidophilus ATCC 4356 daily for 16 weeks. L. acidophilus ATCC 4356 protected ApoE−/− mice from atherosclerosis by reducing their plasma cholesterol levels from 923 ± 44 to 581 ± 18 mg/dl, likely via a marked decrease in cholesterol absorption caused by modulation of Niemann-Pick C1-like 1 (NPC1L1). In addition, suppression of cholesterol absorption induced reverse cholesterol transport (RCT) in macrophages through the peroxisome proliferator-activated receptor/liver X receptor (PPAR/LXR) pathway. Fecal lactobacillus and bifidobacterium counts were significantly (P < 0.05) higher in the L. acidophilus ATCC 4356 treatment groups than in the control groups. Furthermore, L. acidophilus ATCC 4356 was detected in the rat small intestine, colon, and feces during the feeding trial. The bacterial levels remained high even after the administration of lactic acid bacteria had been stopped for 2 weeks. These results suggest that administration of L. acidophilus ATCC 4356 can protect against atherosclerosis through the inhibition of intestinal cholesterol absorption. Therefore, L. acidophilus ATCC 4356 may be a potential therapeutic material for preventing the progression of atherosclerosis. PMID:25261526

  9. Tongxinluo mitigates atherogenesis by regulating angiogenic factors and inhibiting vasa vasorum neovascularization in apolipoprotein E-deficient mice

    PubMed Central

    Ma, Lianyue; Ni, Mei; Hao, Panpan; Lu, Huixia; Yang, Xiaoyan; Xu, Xingli; Zhang, Cheng; Huang, Shanying; Zhao, Yuxia; Liu, Xiaoling; Zhang, Yun

    2016-01-01

    Vasa vasorum (VV) neovascularization contributes to atherogenesis and its expansion and distribution is correlated with intraplaque expression of angiogenic factors. The present study investigated the roles of Tongxinluo (TXL), a traditional Chinese medication, on VV proliferation and atherogenesis. In vitro, TXL pre-treatment reversed the tumor necrosis factor-a (TNF-a) induced expression of vascular endothelial growth factor A (VEGF-A) and angiopoietin-1 (ANGPT-1) but not ANGPT-2, leading to increased ratio of ANGPT-1 to ANGPT-2. Consistently, TXL treatment (at a dosage of 0.38, 0.75, 1.5 g/kg/d, respectively) decreased the expression of VEGF-A while increased that of ANGPT-1 in early atherosclerotic lesions of apolipoprotein E deficient (apoE−/−) mice. On aortic ring assay, microvessels sprouting from aortas were significantly inhibited in TXL-treated mice. Moreover, VV neovascularization in plaques was markedly reduced with TXL treatment. Histological and morphological analysis demonstrated that TXL treatment reduced plaque burden, plaque size and changed the plaque composition. These data suggest that TXL inhibits early atherogenesis through regulating angiogenic factor expression and inhibiting VV proliferation in atherosclerotic plaque. Our study shed new light on the anti-atherosclerotic effect of TXL. PMID:26908443

  10. Influence of apolipoprotein E genotype on the transmission of Alzheimer disease in a community-based sample

    SciTech Connect

    Jarvik, G.P.; Larson, E.B.; Goddard, K.

    1996-01-01

    The {epsilon}4 allele of the apolipoprotein E locus (APOE) has been found to be an important predictor of Alzheimer disease (AD). However, linkage analysis has not clarified the role of APOE in the transmission of AD. The results of the current study provide evidence that the pattern of transmission of memory disorders differs in nuclear families in which the AD-affected proband did carry an {epsilon}4 allele versus those families in which the AD-affected proband did not carry an {epsilon}4 allele. Further, risk of AD due to APOE genotype in the probands is modified by family history of memory disorders, suggesting gene-by-gene interactions. Family history remained a significant predictor of AD for affected probands with some, but not all, APOE genotypes in a logistic regression analysis. Though nonadditive in the prediction of AD, APOE genotype and family history acted additively in the prediction of age at AD onset. The results of complex segregation analysis were inconsistent with Mendelian segregation of memory disorders both in families of affected probands who did or did not carry an {epsilon}4 allele, yet these two groups had significantly different parameter estimates for their transmission models. These results are consistent with gene-by-gene interactions, but also could result from common elements in the familial environment. 41 refs., 1 fig., 7 tabs.

  11. Reduced alpha-lipoic acid synthase gene expression exacerbates atherosclerosis in diabetic apolipoprotein E-deficient mice.

    PubMed

    Yi, Xianwen; Xu, Longquan; Hiller, Sylvia; Kim, Hyung-Suk; Maeda, Nobuyo

    2012-07-01

    To study the effects of reduced lipoic acid gene expression on diabetic atherosclerosis in apolipoprotein E null mice (Apoe(-/-)). Heterozygous lipoic acid synthase gene knockout mice (Lias(+/-)) crossed with Apoe(-/-) mice were used to evaluate the diabetic effect induced by streptozotocin on atherosclerosis in the aortic sinus of the heart. While diabetes markedly increased atherosclerotic plaque size in Apoe(-/-) mice, a small but significant effect of reduced expression of lipoic acid gene was observed in diabetic Lias(+/-)Apoe(-/-) mice. In the aortic lesion area, the Lias(+/-)Apoe(-/-) mice exhibited significantly increased macrophage accumulation and cellular apoptosis than diabetic Lias(+/+)Apoe(-/-) littermates. Plasma glucose, cholesterol, and interleukin-6 were also higher. These abnormalities were accompanied with increased oxidative stress including a decreased ratio of reduced glutathione/oxidized glutathione in erythrocytes, increased systemic lipid peroxidation, and increased Gpx1 and MCP1 gene expression in the aorta. Decreased endogenous lipoic acid gene expression plays a role in development of diabetic atherosclerosis. These findings extend our understanding of the role of antioxidant in diabetic atherosclerosis. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  12. Demographic and Lifestyle Characteristics, but Not Apolipoprotein E Genotype, Are Associated with Intelligence among Young Chinese College Students

    PubMed Central

    Wang, Tingting; Zhang, Zhen-Lian; Wang, Yiwei; Heckman, Michael G.; Diehl, Nancy N.; Zhang, Yun-Wu; Xu, Huaxi; Bu, Guojun

    2015-01-01

    Background Intelligence is an important human feature that strongly affects many life outcomes, including health, life-span, income, educational and occupational attainments. People at all ages differ in their intelligence but the origins of these differences are much debated. A variety of environmental and genetic factors have been reported to be associated with individual intelligence, yet their nature and contribution to intelligence differences have been controversial. Objective To investigate the contribution of apolipoprotein E (APOE) genotype, which is associated with the risk for Alzheimer’s disease, as well as demographic and lifestyle characteristics, to the variation in intelligence. Methods A total of 607 Chinese college students aged 18 to 25 years old were included in this prospective observational study. The Chinese revision of Wechsler Adult Intelligence Scale (the fourth edition, short version) was used to determine the intelligence level of participants. Demographic and lifestyle characteristics data were obtained from self-administered questionnaires. Results No significant association was found between APOE polymorphic alleles and different intelligence quotient (IQ) measures. Interestingly, a portion of demographic and lifestyle characteristics, including age, smoking and sleep quality were significantly associated with different IQ measures. Conclusions Our findings indicate that demographic features and lifestyle characteristics, but not APOE genotype, are associated with intelligence measures among young Chinese college students. Thus, although APOE ε4 allele is a strong genetic risk factor for Alzheimer’s disease, it does not seem to impact intelligence at young ages. PMID:26574747

  13. Apolipoprotein E epsilon 4 allele distribution in Wernicke-Korsakoff syndrome with or without global intellectual deficits.

    PubMed

    Muramatsu, T; Kato, M; Matsui, T; Yoshimasu, H; Yoshino, A; Matsushita, S; Higuchi, S; Kashima, H

    1997-01-01

    Recent genetic studies show that the apolipoprotein E (ApoE) epsilon 4 allele is a risk factor for Alzheimer's disease (AD). Whether this allele is associated with other dementing diseases is the next important question. The information could provide a clue to the pathogenetic role of ApoE. In the present study, patients with Wernicke-Korsakoff syndrome (WKS) of alcoholic etiology were divided into two groups according to the severity of intellectual deficits, i.e., those of "classical" Korsakoff patients with preserved intellectual function other than amnesia and those with global intellectual deficits. Genotyping showed that the frequency of ApoE epsilon 4 allele was significantly higher in the patients with global deficits, suggesting the involvement of this allele in the intellectual decline of WKS. In contrast, distributions of other two markers, alpha 1-antichymotrypsin and presenilin-1, did not differ between the two groups. These results added further support to the notion that the consequence of acute insult to the brain is influenced by the ApoE genotype, and suggested ApoE's role in the development of a certain group of "alcoholic dementia."

  14. Sex Differences in Neuropsychiatric Symptoms of Alzheimer's Disease: The Modifying Effect of Apolipoprotein E ε4 Status.

    PubMed

    Xing, Yi; Tang, Yi; Jia, Jianping

    2015-01-01

    Sex differences in neuropsychiatric symptoms of Alzheimer's disease (AD) have been demonstrated in previous studies, and apolipoprotein E (ApoE) ε4 status influences psychiatric manifestations of AD. However, whether ApoE ε4 status modifies the sex differences in neuropsychiatric symptoms of AD is still unclear. In this study, sex differences in neuropsychiatric abnormalities were stratified and analyzed by ApoE ε4 status in mild AD and moderate to severe AD separately. The Clinical Dementia Rating (CDR) scale and the Neuropsychiatric Inventory (NPI) were used to assess dementia severity and neuropsychiatric symptoms. No sex differences were found in mild AD. In moderate to severe AD, among ε4 positive individuals, disinhibition was significantly more prevalent (8.0% in men versus 43.2% in women, p = 0.003) and severer (p = 0.003) in female patients. The frequency (16.0% in men versus 51.4% in women, p = 0.005) and score (p = 0.004) of irritability were of borderline significance after strict Bonferroni correction. In conclusion, this study supported the modifying effect of ApoE ε4 status on sex differences in neuropsychiatric symptoms of AD, and this modifying effect was pronounced in moderate to severe stage of AD. The interaction between gender and ApoE ε4 status should be considered in studies on neuropsychiatric symptoms of AD.

  15. Comprehensive Plasma Metabolomic Analyses of Atherosclerotic Progression Reveal Alterations in Glycerophospholipid and Sphingolipid Metabolism in Apolipoprotein E-deficient Mice

    PubMed Central

    Dang, Vi T.; Huang, Aric; Zhong, Lexy H.; Shi, Yuanyuan; Werstuck, Geoff H.

    2016-01-01

    Atherosclerosis is the major underlying cause of most cardiovascular diseases. Despite recent advances, the molecular mechanisms underlying the pathophysiology of atherogenesis are not clear. In this study, comprehensive plasma metabolomics were used to investigate early-stage atherosclerotic development and progression in chow-fed apolipoprotein E-deficient mice at 5, 10 and 15 weeks of age. Comprehensive plasma metabolomic profiles, based on 4365 detected metabolite features, differentiate atherosclerosis-prone from atherosclerosis-resistant models. Metabolites in the sphingomyelin pathway were significantly altered prior to detectable lesion formation and at all subsequent time-points. The cytidine diphosphate-diacylglycerol pathway was up-regulated during stage I of atherosclerosis, while metabolites in the phosphatidylethanolamine and glycosphingolipid pathways were augmented in mice with stage II lesions. These pathways, involving glycerophospholipid and sphingolipid metabolism, were also significantly affected during the course of atherosclerotic progression. Our findings suggest that distinct plasma metabolomic profiles can differentiate the different stages of atherosclerotic progression. This study reveals that alteration of specific, previously unreported pathways of glycerophospholipid and sphingolipid metabolism are associated with atherosclerosis. The clear difference in the level of several metabolites supports the use of plasma lipid profiling as a diagnostic tool of atherogenesis. PMID:27721472

  16. Low-density Lipoprotein Receptor Represents an Apolipoprotein E-independent Pathway of Aβ Uptake and Degradation by Astrocytes*

    PubMed Central

    Basak, Jacob M.; Verghese, Philip B.; Yoon, Hyejin; Kim, Jungsu; Holtzman, David M.

    2012-01-01

    Accumulation of the amyloid β (Aβ) peptide within the brain is hypothesized to be one of the main causes underlying the pathogenic events that occur in Alzheimer disease (AD). Consequently, identifying pathways by which Aβ is cleared from the brain is crucial for better understanding of the disease pathogenesis and developing novel therapeutics. Cellular uptake and degradation by glial cells is one means by which Aβ may be cleared from the brain. In the current study, we demonstrate that modulating levels of the low-density lipoprotein receptor (LDLR), a cell surface receptor that regulates the amount of apolipoprotein E (apoE) in the brain, altered both the uptake and degradation of Aβ by astrocytes. Deletion of LDLR caused a decrease in Aβ uptake, whereas increasing LDLR levels significantly enhanced both the uptake and clearance of Aβ. Increasing LDLR levels also enhanced the cellular degradation of Aβ and facilitated the vesicular transport of Aβ to lysosomes. Despite the fact that LDLR regulated the uptake of apoE by astrocytes, we found that the effect of LDLR on Aβ uptake and clearance occurred in the absence of apoE. Finally, we provide evidence that Aβ can directly bind to LDLR, suggesting that an interaction between LDLR and Aβ could be responsible for LDLR-mediated Aβ uptake. Therefore, these results identify LDLR as a receptor that mediates Aβ uptake and clearance by astrocytes, and provide evidence that increasing glial LDLR levels may promote Aβ degradation within the brain. PMID:22383525

  17. Xanthohumol Prevents Atherosclerosis by Reducing Arterial Cholesterol Content via CETP and Apolipoprotein E in CETP-Transgenic Mice

    PubMed Central

    Segawa, Shuichi; Ozaki, Moeko; Kobayashi, Naoyuki; Shigyo, Tatsuro; Chiba, Hitoshi

    2012-01-01

    Background Xanthohumol is expected to be a potent anti-atherosclerotic agent due to its inhibition of cholesteryl ester transfer protein (CETP). In this study, we hypothesized that xanthohumol prevents atherosclerosis in vivo and used CETP-transgenic mice (CETP-Tg mice) to evaluate xanthohumol as a functional agent. Methodology/Principal Findings Two strains of mice, CETP-Tg and C57BL/6N (wild-type), were fed a high cholesterol diet with or without 0.05% (w/w) xanthohumol ad libitum for 18 weeks. In CETP-Tg mice, xanthohumol significantly decreased accumulated cholesterol in the aortic arch and increased HDL cholesterol (HDL-C) when compared to the control group (without xanthohumol). Xanthohumol had no significant effect in wild-type mice. CETP activity was significantly decreased after xanthohumol addition in CETP-Tg mice compared with the control group and it inversely correlated with HDL-C (%) (P<0.05). Furthermore, apolipoprotein E (apoE) was enriched in serum and the HDL-fraction in CETP-Tg mice after xanthohumol addition, suggesting that xanthohumol ameliorates reverse cholesterol transport via apoE-rich HDL resulting from CETP inhibition. Conclusions Our results suggest xanthohumol prevents cholesterol accumulation in atherogenic regions by HDL-C metabolism via CETP inhibition leading to apoE enhancement. PMID:23166663

  18. P-selectin glycoprotein ligand-1 deficiency leads to cytokine resistance and protection against atherosclerosis in apolipoprotein E deficient mice.

    PubMed

    Luo, Wei; Wang, Hui; Ohman, Miina K; Guo, Chiao; Shi, Kate; Wang, Julia; Eitzman, Daniel T

    2012-01-01

    Adhesive interactions between endothelial cells and leukocytes contribute to atherosclerotic plaque growth. However, mechanism(s) responsible for endothelial priming and deactivation in inflammatory diseases such as atherosclerosis are not clear. Apolipoprotein E deficient mice were generated with deficiency of P-selectin glycoprotein ligand-1 (Psgl-1(-/-), ApoE(-/-)). On both standard chow and Western diet, Psgl-1(-/-), ApoE(-/-) mice were protected against atherosclerosis compared to Psgl-1(+/+), ApoE(-/-) controls. Psgl-1(-/-), ApoE(-/-) mice also showed reduced leukocyte rolling and firm attachment on endothelial cells, however, adoptively transferred Psgl-1(+/+), ApoE(-/-) leukocytes into Psgl-1(-/-), ApoE(-/-) hosts displayed similar reduced rolling as Psgl-1(-/-), ApoE(-/-) leukocytes. Hematopoietic deficiency of Psgl-1 conferred resistance to the effects of interleukin-1β (IL-1β) on leukocyte rolling along with reduced circulating levels of sP-sel and sE-sel. Antibody blockade of Psgl-1 also reduced endothelial activation in response to IL-1β, eliminated leukocyte rolling, and was protective against atherosclerosis in ApoE(-/-) mice. Monocyte depletion with clodronate restored the endothelial response to IL-1β in Psgl-1(-/-) mice. This study suggests that Psgl-1 deficiency leads to reduced atherosclerosis and adhesive interactions between endothelial cells and leukocytes by indirectly regulating endothelial responses to cytokine stimulation. Published by Elsevier Ireland Ltd.

  19. Synergistic effects of apolipoprotein E gene epsilon polymorphism and some conventional risk factors on premature ischaemic heart disease development.

    PubMed

    Balcerzyk, Anna; Zak, Iwona; Krauze, Jolanta

    2007-09-01

    Ischaemic heart disease (IHD), which is a clinical manifestation of atherosclerotic changes in coronary arteries, results from the action of multiple genetic and environmental factors. Genetic susceptibility to IHD may be determined by specific polymorphic variants of genes encoding isoforms involved in processes important in the pathogenesis of atherosclerosis. Due to the multifactorial nature of IHD, participation of a single polymorphism in the determination of the disease risk is relatively small. However, it seems that its significance may increase in the presence of a specific genetic or environmental background. To evaluate a possible association between the epsilon polymorphism of the apolipoprotein E gene (apo E) and premature IHD in the Polish population as well as to determine whether the genotype may modulate the influence of conventional risk factors on IHD. We studied 247 caucasian subjects: 140 patients with angiographically confirmed IHD and 107 blood donors without a history of IHD. Polymorphism epsilon of the apo E gene was genotyped using the PCR-RFLP method. We observed a tendency to a higher prevalence of the epsilon4 allele and carriers of this allele in the IHD group compared to controls. However, these differences were not statistically significant. We also observed a synergistic effect between epsilon4 allele carrier state and smoking, elevated level of total cholesterol and, to a lower degree - LDL cholesterol, on IHD risk. Presented data show the synergistic effects between epsilon4 allele carrier state and some traditional risk factors on determining the risk of premature coronary artery disease.

  20. Neuropsychological performance in advanced age: influences of demographic factors and Apolipoprotein E: findings from the Cache County Memory Study.

    PubMed

    Welsh-Bohmer, Katheen A; Ostbye, Truls; Sanders, Linda; Pieper, Carl F; Hayden, Kathleen M; Tschanz, JoAnn T; Norton, Maria C

    2009-01-01

    The Cache County Study of Memory in Aging (CCMS) is an epidemiological study of Alzheimer's disease (AD), mild cognitive disorders, and aging in a population of exceptionally long-lived individuals (7th to 11th decade). Observation of population members without dementia provides an opportunity for establishing the range of normal neurocognitive performance in a representative sample of the very old. We examined neurocognitive performance of the normal participants undergoing full clinical evaluations (n = 507) and we tested the potential modifying effects of apolipoprotein E (APOE) genotype, a known genetic risk factor for the later development of AD. The results indicate that advanced age and low education are related to lower test scores across nearly all of the neurocognitive measures. Gender and APOE epsilon4 both had negligible and inconsistent influences, affecting only isolated measures of memory and expressive speech (in case of gender). The gender and APOE effects disappeared once age and education were controlled. The study of this exceptionally long-lived population provides useful normative information regarding the broad range of "normal" cognition seen in advanced age. Among elderly without dementia or other cognitive impairment, APOE does not appear to exert any major effects on cognition once other demographic influences are controlled.

  1. Dynamic imaging of allogeneic adipose-derived regenerative cells transplanted in ischemic hind limb of apolipoprotein E mouse model

    PubMed Central

    Zheng, Yi; Qin, Jinbao; Wang, Xin; Peng, Zhiyou; Hou, Peiyong; Lu, Xinwu

    2017-01-01

    Background Transplantation of allogeneic adipose-derived regenerative cells (ADRCs) is a promising treatment modality for severe ischemic diseases. However, minimal information is available on the in vivo effects, fate, and migration of ADRCs, as well as the mechanisms of their therapeutic angiogenesis. Materials and methods In this study, green fluorescent protein-expressing ADRCs (GFP-ADRCs) were obtained, labeled with acetylated 3-aminopropyltrimethoxysilane (APTS)-coated iron oxide nanoparticles (APTS NPs), and injected into an old apolipoprotein E knockout (ApoE-KO) mouse model with hind limb ischemia. Then, 3.0 T magnetic resonance imaging (MRI) was performed to dynamically trace the role of ADRCs targeting hind limb ischemia in the ApoE-KO mice model. Results Labeled cells were visualized as large hypointense spots in ischemic muscles by serial 3.0 T MRI scans during a 4-week follow-up. The presence of labeled GFP-ADRCs was confirmed by Prussian blue staining and fluorescence microscopy on postmortem specimens. Conclusion This study showed that allogeneic ADRCs offer great potential application for therapeutic angiogenesis in severe ischemic disease based on the efficacy and feasibility of ADRC transplantation and on the available amounts of tissue. PMID:28053524

  2. USE OF FUSED CIRCULATIONS TO INVESTIGATE THE ROLE OF APOLIPOPROTEIN E AS AMYLOID CATALYST AND PERIPHERAL SINK IN ALZHEIMER'S DISEASE

    PubMed Central

    Nilsson, Lars N. G.; Gografe, Sylvia; Costa, David A.; Hughes, Tiffany; Dressler, David; Potter, Huntington

    2013-01-01

    Apolipoprotein E (apoE) synthesized in liver and brain plays a key role in both cholesterol transport and Alzheimer's disease (AD): apoE-knockout mice develop hypercholesterolemia and atherosclerosis and cannot support AD amyloid deposition. The ApoE4 allele is the strongest genetic risk factor for late-onset AD, and apoE4 protein preferentially catalyzes amyloid-beta (Aβ) peptide fibrillization in vitro and amyloid plaque deposition in vivo. Circulating apoE may also have the potential to draw Aβ from the brain and reduce amyloid deposition. We used parabiosis to determine how circulating apoE impacts brain amyloid deposition and blood cholesterol levels in transgenic mice carrying AD-promoting APP and PS1 human transgenes—either with or without the endogenous mouse apoE gene. ApoE transferred through the joined circulations from WT to parabiosed APP+/+,PS1+/−,apoE-KO mice prevented hypercholesterolemia and reduced already low brain amyloid deposition. The findings indicate that apoE synthesis in the brain itself is necessary for amyloid accumulation. Furthermore, plasma apoE can both normalize cholesterol levels in apoE-KO mice and act as a peripheral sink to induce net efflux of Aβ peptide from the brain. The therapeutic implication is that inhibiting Alzheimer's disease neuropathology may be accomplished by either reducing apoE in the brain or increasing apoE in the blood. PMID:23626867

  3. Chicory, a typical vegetable in Mediterranean diet, exerts a therapeutic role in established atherosclerosis in apolipoprotein E-deficient mice.

    PubMed

    Lin, Weiqun; Liu, Chaoqun; Yang, Hai; Wang, Wenting; Ling, Wenhua; Wang, Dongliang

    2015-09-01

    Since protocatechuic acid exerts an atheroprotective role, we investigated how chicory (Cichorium intybus L. var. foliosum, Belgian endive) rich in protocatechuic acid, a typical vegetable in Mediterranean diet, affects preestablished atherosclerosis progression. Apolipoprotein E-deficient mice fed AIN diets containing 0.5% freeze-dried chicory for 10 weeks displayed a reduction in lesion size with a concomitant improvement in lesion stability indicated by fewer macrophages and more collagen content. Chicory consumption suppressed aortic cholesterol accumulation and intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and monocyte chemoattractant protein-1 expression, whereas it increased aortic ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1) expression. Furthermore, chicory consumption improved peritoneal macrophage phenotype with less cellular cholesterol associated with an enhancement of cholesterol efflux capacity through upregulation of ABCA1 and ABCG1, less cellular oxidative stress associated with an inhibition of nicotinamide adenine dinucleotide phosphate oxidase activity, and weaker inflammatory responses associated with an inhibition of nuclear factor-κB activation. Interestingly, ABCA1 and ABCG1 silencing tended to completely block beneficial effects of chicory in peritoneal macrophages. Chicory exerts an atheroprotective role in mice possibly by regulating lesional macrophage content and phenotype, suggesting that chicory is one underrated contributor to Mediterranean Diet-induced atheroprotection. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Lactobacillus acidophilus ATCC 4356 prevents atherosclerosis via inhibition of intestinal cholesterol absorption in apolipoprotein E-knockout mice.

    PubMed

    Huang, Ying; Wang, Jinfeng; Quan, Guihua; Wang, Xiaojun; Yang, Longfei; Zhong, Lili

    2014-12-01

    The objective of this study was to investigate the effect of Lactobacillus acidophilus ATCC 4356 on the development of atherosclerosis in apolipoprotein E-knockout (ApoE(-/-)) mice. Eight-week-old ApoE(-/-) mice were fed a Western diet with or without L. acidophilus ATCC 4356 daily for 16 weeks. L. acidophilus ATCC 4356 protected ApoE(-/-) mice from atherosclerosis by reducing their plasma cholesterol levels from 923 ± 44 to 581 ± 18 mg/dl, likely via a marked decrease in cholesterol absorption caused by modulation of Niemann-Pick C1-like 1 (NPC1L1). In addition, suppression of cholesterol absorption induced reverse cholesterol transport (RCT) in macrophages through the peroxisome proliferator-activated receptor/liver X receptor (PPAR/LXR) pathway. Fecal lactobacillus and bifidobacterium counts were significantly (P < 0.05) higher in the L. acidophilus ATCC 4356 treatment groups than in the control groups. Furthermore, L. acidophilus ATCC 4356 was detected in the rat small intestine, colon, and feces during the feeding trial. The bacterial levels remained high even after the administration of lactic acid bacteria had been stopped for 2 weeks. These results suggest that administration of L. acidophilus ATCC 4356 can protect against atherosclerosis through the inhibition of intestinal cholesterol absorption. Therefore, L. acidophilus ATCC 4356 may be a potential therapeutic material for preventing the progression of atherosclerosis. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  5. Adlayers of C60-C60 and C60-C70 fullerene dimers formed on au(111) in benzene solutions studied by STM and LEED.

    PubMed

    Matsumoto, Masashi; Inukai, Junji; Tsutsumi, Eishi; Yoshimoto, Soichiro; Itaya, Kingo; Ito, Osamu; Fujiwara, Koichi; Murata, Michihisa; Murata, Yasujiro; Komatsu, Koichi

    2004-02-17

    Scanning tunneling microscopy (STM) and low-energy electron diffraction were used to reveal the structures of ordered adlayers of [2+2]-type C60-C60 fullerene dimer (C120) and C60-C70 cross-dimer (C130) formed on Au(111) by immersingit in abenzene solution containing C120 or C130 molecules. High-resolution STM images clearly showed the packing arrangements and the electronic structures of C120 and C130 on the Au(111) surface in ultrahigh vacuum. The (2 square root3 x 4square root3)R30 degrees, (2square root3 x 5square root3)R30 degrees, and (7 x 7) structures were found for the C120 adlayer on the Au(111) surface, whereas C130 molecules were closely packed on the surface. Each C60 or C70 monomer cage was discerned in the STM image of a C130 molecule.

  6. Antibody-mediated activation of a defective beta-D-galactosidase: dimeric form of the activatable mutant enzyme.

    PubMed

    Conway de Macario, E; Ellis, J; Guzman, R; Rotman, B

    1978-02-01

    Sedimentation analyses of AMEF, an activatable mutant beta-D-galactosidase (beta-D-galactoside galactohydrolase, EC 3.2.1.23), and the products of its reaction with Fab fragments of activating antibody show that this enzyme exists mainly as 10S dimers. Activation of AMEF by purified antibody resulted in formation of 16S tetramers. A unifying hypothesis postulating a dimer--tetramer equilibrium accounts for this observation as the counterpart of inactivation, which was shown to involve the breakdown of tetramers into inactive subunits [Roth, R. A. & Rotman, B. (1975) Biochem. Biophys. Res. Commun. 67, 1382--1390]. Conditions are described under which AMEF loses the specific antigenic determinant(s) responsible for binding activating antibody, allowing its subsequent use as an absorption to obtain immunologically purified activating antibody,

  7. Antibody-mediated activation of a defective beta-D-galactosidase: dimeric form of the activatable mutant enzyme.

    PubMed Central

    de Macario, E C; Ellis, J; Guzman, R; Rotman, B

    1978-01-01

    Sedimentation analyses of AMEF, an activatable mutant beta-D-galactosidase (beta-D-galactoside galactohydrolase, EC 3.2.1.23), and the products of its reaction with Fab fragments of activating antibody show that this enzyme exists mainly as 10S dimers. Activation of AMEF by purified antibody resulted in formation of 16S tetramers. A unifying hypothesis postulating a dimer--tetramer equilibrium accounts for this observation as the counterpart of inactivation, which was shown to involve the breakdown of tetramers into inactive subunits [Roth, R. A. & Rotman, B. (1975) Biochem. Biophys. Res. Commun. 67, 1382--1390]. Conditions are described under which AMEF loses the specific antigenic determinant(s) responsible for binding activating antibody, allowing its subsequent use as an absorption to obtain immunologically purified activating antibody, PMID:416439

  8. Crystal Structure of a Human Single Domain Antibody Dimer Formed through VH-VH Non-Covalent Interactions

    PubMed Central

    Li, Shenghua; Tanha, Jamshid; Arbabi-Ghahroudi, Mehdi; Zhang, Jianbing; Wang, Shuying

    2012-01-01

    Single-domain antibodies (sdAbs) derived from human VH are considered to be less soluble and prone to aggregate which makes it difficult to determine the crystal structures. In this study, we isolated and characterized two anti-human epidermal growth factor receptor-2 (HER2) sdAbs, Gr3 and Gr6, from a synthetic human VH phage display library. Size exclusion chromatography and surface plasmon resonance analyses demonstrated that Gr3 is a monomer, but that Gr6 is a strict dimer. To understand this different molecular behavior, we solved the crystal structure of Gr6 to 1.6 Å resolution. The crystal structure revealed that the homodimer assembly of Gr6 closely mimics the VH-VL heterodimer of immunoglobulin variable domains and the dimerization interface is dominated by hydrophobic interactions. PMID:22253912

  9. Silencing of Anticoagulant Protein C Evokes Low-Incident but Spontaneous Atherothrombosis in Apolipoprotein E-Deficient Mice-Brief Report.

    PubMed

    Ouweneel, Amber B; Heestermans, Marco; Verwilligen, Robin A F; Gijbels, Marion J J; Reitsma, Pieter H; Van Eck, Miranda; van Vlijmen, Bart J M

    2017-05-01

    Murine atherosclerosis models do not spontaneously develop atherothrombotic complications. We investigated whether disruption of natural anticoagulation allows preexisting atherosclerotic plaques to progress toward an atherothrombotic phenotype. On lowering of plasma protein C levels with small interfering RNA (siProc) in 8-week Western-type diet-fed atherosclerotic apolipoprotein E-deficient mice, 1 out of 4 mice displayed a large, organized, and fibrin- and leukocyte-rich thrombus on top of an advanced atherosclerotic plaque located in the aortic root. Although again at low incidence (3 in 25), comparable thrombi at the same location were observed during a second independent experiment in 9-week Western-type diet-fed apolipoprotein E-deficient mice. Mice with thrombi on their atherosclerotic plaques did not show other abnormalities and had equally lowered plasma protein C levels as siProc-treated apolipoprotein E-deficient mice without thrombi. Fibrinogen and thrombin-antithrombin concentrations and blood platelet numbers were also comparable, and plaques in siProc mice with thrombi had a similar composition and size as plaques in siProc mice without thrombi. Seven out of 25 siProc mice featured clots in the left atrium of the heart. Our findings indicate that small interfering RNA-mediated silencing of protein C in apolipoprotein E-deficient mice creates a condition that allows the occurrence of spontaneous atherothrombosis, albeit at a low incidence. Lowering natural anticoagulation in atherosclerosis models may help to discover factors that increase atherothrombotic complications. © 2017 American Heart Association, Inc.

  10. Expression of mRNA of apolipoprotein E, apolipoprotein A-IV, and matricellular proteins in the myocardium and intensity of fibroplastic processes during experimental hypercholesterolemia.

    PubMed

    Lushnikova, E L; Nepomnyashchikh, L M; Pichigin, V I; Klinnikova, M G; Nepomnyashchikh, R D; Sergeevichev, D S

    2013-12-01

    The expression of mRNA of matricellular proteins (osteopontin, and lumican), apolipoproteins E and A-IV, and microsomal triglyceride transfer protein, and the intensity of fibroplastic processes were studied in the myocardium of rats during experimental chronic hypercholesterolemia. We have found that the development of chronic hypercholesterolemia was followed by an increase in volume density of interstitial connective tissue in the myocardium reflecting the activation of fibroplastic processes. A slight positive correlation was observed between the connective tissue density in the myocardium and expression of osteopontin mRNA (r=0.408) and lumican mRNA (r=0.470). Myocardium remodeling during hypercholesterolemia is realized against the background of increased expression of apolipoproteins E and A-IV mRNA and microsomal triglyceride transfer protein mRNA involved in transport and metabolism of lipoproteins in several tissues and probably play a pivotal role in the regulation of lipoprotein transport and metabolism in the myocardium. We concluded that the increase in the expression of apolipoproteins (E and A-IV) and microsomal triglyceride transfer protein play adaptive and compensatory role and is related to the increase in lipoprotein utilization by macrophages.

  11. Dimerization interfaces formed between the DNA binding domains determine the cooperative binding of RXR/RAR and RXR/TR heterodimers to DR5 and DR4 elements.

    PubMed Central

    Zechel, C; Shen, X Q; Chambon, P; Gronemeyer, H

    1994-01-01

    We have previously reported that the binding site repertoires of heterodimers formed between retinoid X receptor (RXR) and either retinoic acid receptor (RAR) or thyroid hormone receptor (TR) bound to response elements consisting of directly repeated PuG(G/T)TCA motifs spaced by 1-5 bp [direct repeat (DR) elements 1-5] are highly similar to those of their corresponding DNA binding domains (DBDs). We have now mapped the dimerization surfaces located in the DBDs of RXR, RAR and TR, which are responsible for cooperative interaction on DR4 (RXR and TR) and DR5 (RXR and RAR). The D-box of the C-terminal CII finger of RXR provides one of the surfaces which is specifically required for the formation of the heterodimerization interfaces on both DR4 and DR5. Heterodimerization with the RXR DBD on DR5 specifically requires the tip of the RAR CI finger as the complementary surface, while a 7 amino acid sequence encompassing the 'prefinger region', but not the TR CI finger, is specifically required for efficient dimerization of TR and RXR DBDs on DR4. Importantly, DBD swapping experiments demonstrate not only that the binding site repertoires of the full-length receptors are dictated by those of their DBDs, but also that the formation of distinct dimerization interfaces between the DBDs are the critical determinants for cooperative DNA binding of these receptors to specific DRs. Images PMID:8137825

  12. A differential association of Apolipoprotein E isoforms with the Aβ oligomer in solution

    PubMed Central

    Petrlova, Jitka; Hong, Hyun-Seok; Bricarello, Daniel; Harishchandra, Ghimire; Lorigan, Gary; Jin, Lee-Way; Voss, John C.

    2010-01-01

    The molecular pathogenesis of disorders arising from protein mis-folding and aggregation is difficult to elucidate, involving a complex ensemble of intermediates whose toxicity depends upon their state of progression along distinct processing pathways. To address the complex mis-folding and aggregation that initiates the toxic cascade resulting in Alzheimer's disease, we have developed a TOAC spin-labeled Aβ peptide to observe its isoform-dependent interaction with the apoE protein. While most individuals carry the E3 isoform of apoE, approximately 15% of humans carry the E4 isoform, which is recognized as the most significant genetic determinant for Alzheimer's. ApoE is consistently associated with the amyloid plaque marker for Alzheimer's disease. A vital question centers on the influence of the two predominant isoforms, E3 and E4, on Aβ peptide processing and hence Aβ toxicity. We employed EPR spectroscopy of incorporated spin labels to investigate the interaction of apoE with the toxic oligomeric species of Aβ in solution. EPR spectra of the spin labeled side chain report on side chain and backbone dynamics, as well as the spatial proximity of spins in an assembly. Our results indicate oligomer binding involves the C-terminal domain of apoE, with apoE3 reporting a much greater response through this conformational marker. Coupled with SPR binding measurements, apoE3 displays a higher affinity and capacity for the toxic Aβ oligomer. These findings support the hypothesis that apoE polymorphism and Alzheimer's risk can largely be attributed to the reduced ability of apoE4 to function as a clearance vehicle for the toxic form of Aβ. PMID:21069870

  13. Dipeptidyl peptidase-4 inhibitor, linagliptin, ameliorates endothelial dysfunction and atherogenesis in normoglycemic apolipoprotein-E deficient mice.

    PubMed

    Salim, Hotimah Masdan; Fukuda, Daiju; Higashikuni, Yasutomi; Tanaka, Kimie; Hirata, Yoichiro; Yagi, Shusuke; Soeki, Takeshi; Shimabukuro, Michio; Sata, Masataka

    2016-04-01

    Dipeptidyl peptidase-4 (DPP-4) inhibitors have vasoprotective effects. This study investigated whether a recently approved DPP-4 inhibitor, linagliptin (Lina), suppresses atherogenesis in non-diabetic apolipoprotein-E deficient (ApoE(-/-)) mice, and examined its effects on endothelial function. Lina (10mg/kg/day) was administered orally to ApoE(-/-) mice for 20 weeks. Lina reduced atherogenesis without alteration of metabolic parameters including blood glucose level compared with control (P<0.05). Results of immunohistochemical analyses and quantitative RT-PCR demonstrated that Lina significantly decreased inflammatory molecule expression and macrophage infiltration in the atherosclerotic aorta. Lina administration to ApoE(-/-) mice for 9 weeks ameliorated endothelium-dependent vasodilation compared with that in untreated mice. Plasma active glucagon-like peptide-1 (GLP-1) level was significantly higher in the treated group (P<0.05). Exendin-4 (Ex-4), a GLP-1 analog, ameliorated endothelium-dependent vasodilation impaired by palmitic acid (PA) in wild-type mouse aortic segments. Ex-4 promoted phosphorylation of eNOS(Ser1177) and Akt, both of which were abrogated by PA, in human umbilical vein endothelial cells. In addition, Lina administration to ApoE(-/-) mice decreased oxidative stress, as determined by urinary 8-OHdG secretion and NADPH oxidase subunit expression in the abdominal aorta. Lina inhibited atherogenesis in non-diabetic ApoE(-/-) mice. Amelioration of endothelial dysfunction associated with a reduction of oxidative stress by GLP-1 contributes to the atheroprotective effects of Lina. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. 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.

  15. Rapid detection of apolipoprotein E genotypes in Alzheimer's disease using polymerase chain reaction-single strand conformation polymorphism.

    PubMed

    Kamruecha, Worawan; Chansirikarnjana, Sirintorn; Nimkulrat, Ekapot; Udommongkol, Chesda; Wongmek, Wanna; Thangnipon, Wipawan

    2006-07-01

    Apolipoprotein E (APOE) gene on chromosome 19q13.2 is encoded by three common alleles designated as epsilon2, epsilon3 and epsilon4. In Alzheimer's disease (AD) the epsilon4 allele is over-represented and is considered to be a major genetic risk factor. Several methods have been developed to determine APOE genotypes. Among them, polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) appears to be highly reliable. In this study, we improved the nonisotopic PCR-SSCP method for determining APOE genotypes in 42 cases of AD patients, 40 cases of non-AD dementia patients, and 49 cases of age-matched controls. DNA from the target sequence on APOE was amplified by PCR from peripheral blood genomic DNA. PCR products were electrophoresed in a non-denaturing polyacrylamide gel and visualized by silver staining. We found that the epsilon4 allele had a significantly high frequency of occurrence in AD patients (33.3%) compared with age-matched controls (13.3%) (chi(2) = 10.43, p = 0.001) and non-AD dementia (10%) (chi(2) = 13.02, p<0.001) whereas the epsilon3 allele was of high frequency in non-AD dementia (90%) compared with age-matched controls (85.7%) and AD patients (66.7%). APOE epsilon4 homozygotes were found only in AD groups. On the other hand, the epsilon2 allele was found only in an age-matched control. This study confirmed that the APOE psilon4 allele is a risk factor in Thai AD subjects and that the PCR-SSCP method is a rapid and useful means of detecting the APOE genotype in AD.

  16. Association of Docosahexaenoic Acid Supplementation With Alzheimer Disease Stage in Apolipoprotein E ε4 Carriers: A Review.

    PubMed

    Yassine, Hussein N; Braskie, Meredith N; Mack, Wendy J; Castor, Katherine J; Fonteh, Alfred N; Schneider, Lon S; Harrington, Michael G; Chui, Helena C

    2017-03-01

    The apolipoprotein E ε4 (APOE4) allele identifies a unique population that is at significant risk for developing Alzheimer disease (AD). Docosahexaenoic acid (DHA) is an essential ω-3 fatty acid that is critical to the formation of neuronal synapses and membrane fluidity. Observational studies have associated ω-3 intake, including DHA, with a reduced risk for incident AD. In contrast, randomized clinical trials of ω-3 fatty acids have yielded mixed and inconsistent results. Interactions among DHA, APOE genotype, and stage of AD pathologic changes may explain the mixed results of DHA supplementation reported in the literature. Although randomized clinical trials of ω-3 in symptomatic AD have had negative findings, several observational and clinical trials of ω-3 in the predementia stage of AD suggest that ω-3 supplementation may slow early memory decline in APOE4 carriers. Several mechanisms by which the APOE4 allele could alter the delivery of DHA to the brain may be amenable to DHA supplementation in predementia stages of AD. Evidence of accelerated DHA catabolism (eg, activation of phospholipases and oxidation pathways) could explain the lack of efficacy of ω-3 supplementation in AD dementia. The association of cognitive benefit with DHA supplementation in predementia but not AD dementia suggests that early ω-3 supplementation may reduce the risk for or delay the onset of AD symptoms in APOE4 carriers. Recent advances in brain imaging may help to identify the optimal timing for future DHA clinical trials. High-dose DHA supplementation in APOE4 carriers before the onset of AD dementia can be a promising approach to decrease the incidence of AD. Given the safety profile, availability, and affordability of DHA supplements, refining an ω-3 intervention in APOE4 carriers is warranted.

  17. Structural Variation in Human Apolipoprotein E3 and E4: Secondary Structure, Tertiary Structure, and Size Distribution

    PubMed Central

    Chou, Chi-Yuan; Lin, Yi-Ling; Huang, Yu-Chyi; Sheu, Sheh-Yi; Lin, Ta-Hsien; Tsay, Huey-Jen; Chang, Gu-Gang; Shiao, Ming-Shi

    2005-01-01

    Human apolipoprotein E (apoE) is a 299-amino-acid protein with a molecular weight of 34 kDa. The difference between the apoE3 and apoE4 isoforms is a single residue substitution involving a Cys-Arg replacement at residue 112. ApoE4 is positively associated with atherosclerosis and late-onset and sporadic Alzheimer's disease (AD). ApoE4 and its C-terminal truncated fragments have been found in the senile plaques and neurofibrillary tangles in the brain of AD patients. However, detail structural information regarding isoform and domain interaction remains poorly understood. We prepared full-length, N-, and C-terminal truncated apoE3 and apoE4 proteins and studied their structural variation. Sedimentation velocity and continuous size distribution analysis using analytical ultracentrifugation revealed apoE372-299 as consisting of a major species with a sedimentation coefficient of 5.9. ApoE472-299 showed a wider and more complicated species distribution. Both apoE3 and E4 N-terminal domain (1–191) existed with monomers as the major component together with some tetramer. The oligomerization and aggregation of apoE protein increased when the C-terminal domain (192–271) was incorporated. The structural influence of the C-terminal domain on apoE is to assist self-association with no significant isoform preference. Circular dichroism and fluorescence studies demonstrated that apoE472-299 possessed a more α-helical structure with more hydrophobic residue exposure. The structural variation of the N-terminal truncated apoE3 and apoE4 protein provides useful information that helps to explain the greater aggregation of the apoE4 isoform and thus has implication for the involvement of apoE4 in AD. PMID:15475580

  18. Metformin reduces the endotoxin-induced down-regulation of apolipoprotein E gene expression in macrophages

    SciTech Connect

    Stavri, Simona; Trusca, Violeta G.; Simionescu, Maya; Gafencu, Anca V.

    2015-05-29

    The atheroprotective role of macrophage-derived apolipoprotein E (apoE) is well known. Our previous reports demonstrated that inflammatory stress down-regulates apoE expression in macrophages, aggravating atherogenesis. Metformin, extensively used as an anti-diabetic drug, has also anti-inflammatory properties, and thus confers vascular protection. In this study, we questioned whether metformin could have an effect on apoE expression in macrophages in normal conditions or under lipopolysaccharide (LPS)-induced stress. The results showed that metformin slightly increases the apoE expression only at high doses (5–10 mM). Low doses of metformin (1–3 mM) significantly reduce the LPS down-regulatory effect on apoE expression in macrophages. Our experiments demonstrated that LPS-induced NF-κB binds to the macrophage-specific distal regulatory element of apoE gene, namely to the multienhancer 2 (ME.2) and its 5′-deletion fragments. The NF-κB binding on ME.2 and apoE promoter has a down-regulatory effect. In addition, data revealed that metformin impairs NF-κB nuclear translocation, and thus, improves the apoE levels in macrophages under inflammatory stress. The positive effect of metformin in the inflammatory states, its clinical safety and low cost, make this drug a potential adjuvant in the therapeutic strategies for atherosclerosis. - Highlights: • High doses of metformin slightly increase apoE expression in macrophages. • Low doses of metformin up-regulate apoE gene in endotoxin-stressed macrophages. • Metformin reduces the negative effect of LPS on apoE expression by NF-κB inhibition.

  19. An efficient on-column expressed protein ligation strategy: Application to segmental triple labeling of human apolipoprotein E3

    PubMed Central

    Zhao, Wentao; Zhang, Yonghong; Cui, Chunxian; Li, Qianqian; Wang, Jianjun

    2008-01-01

    Expressed protein ligation (EPL) is an intein-based approach that has been used for protein engineering and biophysical studies of protein structures. One major problem of the EPL is the low yield of final ligation product, primarily due to the complex procedure of the EPL, preventing EPL from gaining popularity in the research community. Here we report an efficient on-column EPL strategy, which focuses on enhancing the expression level of the intein-fusion protein that generates thioester for the EPL. We applied this EPL strategy to human apolipoprotein E (apoE) and routinely obtained 25–30 mg segmental, triple-labeled apoE from 1-L cell culture. The approaches reported here are general approaches that are not specific for apoE, thus providing a general strategy for a highly efficient EPL. In addition, we also report an isotopic labeling scheme that double-labels one domain and keeps the other domain of apoE deuterated. Such an isotopic labeling scheme can only be achieved using the EPL strategy. Our data indicated that the segmental triple-labeled apoEs using this labeling scheme produced high-quality, simplified NMR spectra, facilitating NMR spectral assignment. For large proteins, such as apoE, perdeuterated protein samples have to be used to reduce the linewidth of NMR signals, causing a major problem for the NOE-based NMR method, since perdeuterated proteins lack protons for NOE measurement. The new labeling strategy solves this problem and provides 13C/15N double-labeled, protonated protein domains, allowing for determination of high-resolution NMR structure of these large proteins. PMID:18305193

  20. Human recombinant apolipoprotein E redirects lipopolysaccharide from Kupffer cells to liver parenchymal cells in rats In vivo.

    PubMed Central

    Rensen, P C; Oosten, M; Bilt, E; Eck, M; Kuiper, J; Berkel, T J

    1997-01-01

    Chylomicrons have been shown to protect mice and rats against a lethal dose of lipopolysaccharide and may serve as a therapeutic means to protect against endotoxemia. However, the requisite of isolation from human lymph hampers pharmaceutical application. Recently, we developed recombinant chylomicrons from commercially available lipids and human recombinant apolipoprotein E. The current study explored the effectiveness of these apoE-enriched emulsions in redirecting LPS from Kupffer cells to liver parenchymal cells. Upon injection into rats, 125I-LPS rapidly and specifically associated with the liver (64.3+/-3.1% of the injected dose) and spleen (4.1+/-0.7%). The uptake of LPS by the spleen was four- to fivefold reduced upon incubation with the apoE-enriched emulsion or free apoE (P < 0.0001), but not with emulsion alone or Lipofundin. Within the liver, 125I-LPS mainly associated with Kupffer cells. The uptake by Kupffer cells was eight- to ninefold reduced by the apoE-enriched emulsion or apoE alone (P < 0.01), and a 19.6-fold increased uptake ratio by liver parenchymal cells over Kupffer cells was observed. The emulsion without apoE had no effect on the in vivo kinetics of LPS. LPS interacted selectively with the apoE moiety of the recombinant chylomicron. Emulsion-associated and free apoE bound approximately two molecules of LPS, possibly by its exposed hydrophilic domain involving arginine residues. We anticipate that the protecting effect of endogenous chylomicrons against LPS-induced endotoxemia may result from the apoE moiety and that human recombinant apoE may serve as a therapeuticum to protect against endotoxemia. PMID:9153287

  1. Cytochrome P450 1B1 Contributes to the Development of Atherosclerosis and Hypertension in Apolipoprotein E-Deficient Mice.

    PubMed

    Song, Chi Young; Ghafoor, Khuzema; Ghafoor, Hafiz U; Khan, Nayaab S; Thirunavukkarasu, Shyamala; Jennings, Brett L; Estes, Anne M; Zaidi, Sahar; Bridges, Dave; Tso, Patrick; Gonzalez, Frank J; Malik, Kafait U

    2016-01-01

    Cytochrome P450 (CYP) 1B1 contributes to vascular smooth muscle cell growth and hypertension in male mice. This study was conducted to determine the contribution of CYP1B1 to the development of atherosclerosis and hypertension and associated pathogenesis in 8-week-old male apolipoprotein E-deficient (ApoE(-/-)/Cyp1b1(+/+)), and ApoE- and CYP1B1-deficient (ApoE(-/-)/Cyp1b1(-/-)) mice fed a normal or atherogenic diet for 12 weeks. A separate group of ApoE(-/-)/Cyp1b1(+/+) mice on an atherogenic diet was injected every third day with the CYP1B1 inhibitor, 2,3',4,5'-tetramethoxystilbene (300 μg/kg), or its vehicle, dimethyl sulfoxide (30 μL, IP); systolic blood pressure was measured by the tail cuff method. After 12 weeks, mice were euthanized, blood collected for lipid analysis, and aortas harvested for measuring lesions and remodeling, and for infiltration of inflammatory cells by histological and immunohistochemical analysis, respectively, and for reactive oxygen species production. Blood pressure, areas of lipids and collagen deposition, elastin breaks, infiltration of macrophages and T lymphocytes, reactive oxygen species generation in the aorta, and plasma lipid levels were increased in ApoE(-/-)/Cyp1b1(+/+) mice on an atherogenic diet; these changes were minimized in mice given 2,3',4,5'-tetramethoxystilbene, and in ApoE(-/-)/Cyp1b1(-/-) mice on an atherogenic diet; absorption/production of lipids remained unaltered in these mice. These data suggest that aortic lesions, hypertension, and associated pathogenesis in ApoE(-/-)/Cyp1b1(+/+) mice on an atherogenic diet are most likely dependent on CYP1B1-generated oxidative stress and increased plasma lipid levels independent of blood pressure and absorption of lipids. CYP1B1 could serve as a novel target for developing drugs to treat atherosclerosis and hypertension caused by hypercholesterolemia.

  2. The relationship of the apolipoprotein E gene polymorphism in Turkish Type 2 Diabetic Patients with and without diabetic foot ulcers.

    PubMed

    Mehmet, Erdogan; Zuhal, Eroglu; Mustafa, Kulaksizoglu; Soner, Solmaz; Aslı, Tetik; Sevki, Cetinkalp

    2016-01-01

    The aim of this study was to investigate the association between Apolipoprotein E (ApoE) gene polymorphism in the development of diabetic foot ulcers in Type 2 diabetes Turkish patients. The ApoE genotypes were determined retrospectively in 50 patients with diabetic foot and 50 without diabetic foot and a control group of 50 healthy individuals. The genotype ApoE distribution did differ between the control group (E2E3 44%, E3E3 38%, E3E4 18%) and Type 2 Diabetic Patients (E2E3 6%, E3E3 81%, E3E4 16%) (p<0.001). The genotype ApoE distribution did not differ between Type 2 Diabetic Patients group (E2E3 4%, E3E3 86%, E3E4 4%) and diabetic foot ulcers (E2E3 8%, E3E3 76%, E3E4 16%) (p>0.05). The frequency of the E2,E3,E4 allele in between the control group and Type 2 Diabetic Patients were no similar for the groups (E2 22%, E3 69%, E4 9% and E2 3%, E3 90.5%, E4 6.5%, respectively) (p<0.001). The frequency of the E2-E4 allele in between the Type 2 Diabetic Patients and diabetic foot ulcers were similar for the groups (E2 2%, E3 93%, E4 5% and E2 4%, E3 88%, E4 8%, respectively) (p>0.05). The gene polymorphism of ApoE and E3 allele are a risk factor for diabetes, but gene polymorphism of ApoE is not an independent risk factor for diabetic foot. Lack of association between ApoE gene polymorphism and Type 2 diabetic foot ulcers might be due to ethnic differences. Copyright © 2015 Diabetes India. Published by Elsevier Ltd. All rights reserved.

  3. Apolipoprotein E and Clusterin can magnify effects of personality vulnerability on declarative memory performance in non-demented older adults.

    PubMed

    Sapkota, Shraddha; Wiebe, Sandra A; Small, Brent J; Dixon, Roger A

    2016-05-01

    Recent research has linked psychological (personality) factors and specific genetic risk polymorphisms to performance on neurocognitive phenotypes. We examined whether episodic or semantic memory performance is associated with (a) three personality traits (i.e. neuroticism, extraversion, and openness to experience), (b) two neurodegenerative-related polymorphisms (i.e. Apolipoprotein E (APOE; rs7412; rs429358), Clusterin (CLU; rs11136000)), and (c) cross-domain risk interactions (magnification effects). Linear growth models were examined to test independent associations between personality traits and declarative memory performance, and potential interaction effects with APOE and CLU genetic risk. Normal older adults (n = 282) with personality and genetic data from the Victoria Longitudinal Study were included at baseline and for up to 14 years of follow-up. First, we observed that higher openness to experience levels were associated with better episodic and semantic memory. Second, three significant gene × personality interactions were associated with poorer memory performance at baseline. These synergistic effects are: (a) APOE allelic risk (ε4+) carriers with lower openness to experience levels, (b) CLU (no risk: T/T) homozygotes with higher extraversion levels, and (c) CLU (no risk: T/T) homozygotes with lower neuroticism levels. Specific neurodegenerative-related genetic polymorphisms (i.e. APOE and CLU) moderate and magnify the risk contributed by selected personality trait levels (i.e. openness to experience, extraversion) on declarative memory performance in non-demented aging. Future research could target interactions of other personality traits and genetic polymorphisms in different clinical populations to predict other neurocognitive deficits or transitions to cognitive impairment and dementia. Copyright © 2015 John Wiley & Sons, Ltd.

  4. Atorvastatin Upregulates the Expression of miR-126 in Apolipoprotein E-knockout Mice with Carotid Atherosclerotic Plaque.

    PubMed

    Pan, Xudong; Hou, Rongyao; Ma, Aijun; Wang, Ting; Wu, Mei; Zhu, Xiaoyan; Yang, Shaonan; Xiao, Xing

    2017-01-01

    Carotid atherosclerosis (AS) is a chronic inflammatory disease of the carotid arterial wall, which is very important in terms of the occurrence of cerebral vascular accidents. Studies have demonstrated that microRNAs (miRNAs) and their target genes are involved in the formation of atherosclerosis and that atorvastatin might reduce atherosclerotic plaques by regulating the expression of miRNAs. However, the related mechanism is not yet known. In this study, we first investigated the effects of atorvastatin on miR-126 and its target gene, i.e., vascular cell adhesion molecule-1 (VCAM-1) in apolipoprotein E-knockout (ApoE-/-) mice with carotid atherosclerotic plaque in vivo. We compared the expressions of miR-126 and VCAM-1 between the control, atherosclerotic model and atorvastatin treatment groups of ApoE-/- mice using RT-PCR and Western blot. We found the miR-126 expression was significantly down-regulated, and the VCAM-1 expression was significantly up-regulated in the atherosclerotic model group, which accelerated the progression of atherosclerosis in the ApoE-/- mice. These results following atorvastatin treatment indicated that miR-126 expression was significantly up-regulated, VCAM-1 expression was significantly down-regulated and atherosclerotic lesions were reduced. The present results might explain the mechanism by which miR-126 is involved in the formation of atherosclerosis in vivo. Our study first indicated that atorvastatin might exert its anti-inflammatory effects in atherosclerosis by regulating the expressions of miR-126 and VCAM-1 in vivo.

  5. Aronia melanocarpa (chokeberry) polyphenol-rich extract improves antioxidant function and reduces total plasma cholesterol in apolipoprotein E knockout mice.

    PubMed

    Kim, Bohkyung; Ku, Chai Siah; Pham, Tho X; Park, Youngki; Martin, Derek A; Xie, Liyang; Taheri, Rod; Lee, Jiyoung; Bolling, Bradley W

    2013-05-01

    We hypothesized that a polyphenol-rich chokeberry extract (CBE) would modulate hepatic lipid metabolism and improve antioxidant function in apolipoprotein E knockout (apoE(-/-)) mice. ApoE(-/-) mice were fed diets containing 15% fat with 0.2% cholesterol alone or supplemented with 0.005% or 0.05% CBE for 4 weeks. CBE polyphenol content was determined by the total phenols, 4-dimethylaminocinnamaldehyde, and ultra high-performance liquid chromatography-mass spectrometry methods. The 0.05% CBE diet provided mice with mean daily doses of 1.2 mg gallic acid equivalents of total phenols, 0.19 mg anthocyanins, 0.17 mg phenolic acids, 0.06 mg proanthocyanidins (as catechin-equivalents), and 0.02 mg flavonols. The 0.05% CBE group had 12% less plasma total cholesterol concentrations than the control. Despite the hypocholesterolemic effect of CBE, hepatic mRNA levels of low-density lipoprotein receptor, hydroxyl-3-methylglutaryl coenzyme A reductase and cholesterol 7α-hydroxylase in CBE-fed mice were not significantly different from controls. Dietary CBE did not alter hepatic lipid content or the hepatic expression of genes involved in lipogenesis and fatty acid β-oxidation such as fatty acid synthase, carnitine palmitoyltransferase 1 and acyl-CoA oxidase. Plasma paraoxonase and catalase activities were significantly increased in mice fed 0.05% CBE. Both CBE diets increased hepatic glutathione peroxidase (GPx) activity but the 0.05% CBE group had 24% less proximal intestine GPx activity relative to controls. Thus, dietary CBE lowered total cholesterol and improved plasma and hepatic antioxidant function at nutritionally-relevant doses in apoE(-/-) mice. Furthermore, the CBE cholesterol-lowering mechanism in apoE(-/-) mice was independent of hepatic expression of genes involved in cholesterol metabolism.

  6. Apolipoprotein E (APOE) genotype has dissociable effects on memory and attentional-executive network function in Alzheimer's disease.

    PubMed

    Wolk, David A; Dickerson, Bradford C

    2010-06-01

    The epsilon4 allele of the apolipoprotein E (APOE) gene is the major genetic risk factor for Alzheimer's disease (AD), but limited work has suggested that APOE genotype may modulate disease phenotype. Carriers of the epsilon4 allele have been reported to have greater medial temporal lobe (MTL) pathology and poorer memory than noncarriers. Less attention has focused on whether there are domains of cognition and neuroanatomical regions more affected in noncarriers. Further, a major potential confound of prior in vivo studies is the possibility of different rates of clinical misdiagnosis for carriers vs. noncarriers. We compared phenotypic differences in cognition and topography of regional cortical atrophy of epsilon4 carriers (n = 67) vs. noncarriers (n = 24) with mild AD from the Alzheimer's Disease Neuroimaging Initiative, restricted to those with a cerebrospinal fluid (CSF) molecular profile consistent with AD. Between-group comparisons were made for psychometric tests and morphometric measures of cortical thickness and hippocampal volume. Carriers displayed significantly greater impairment on measures of memory retention, whereas noncarriers were more impaired on tests of working memory, executive control, and lexical access. Consistent with this cognitive dissociation, carriers exhibited greater MTL atrophy, whereas noncarriers had greater frontoparietal atrophy. Performance deficits in particular cognitive domains were associated with disproportionate regional brain atrophy within nodes of cortical networks thought to subserve these cognitive processes. These convergent cognitive and neuroanatomic findings in individuals with a CSF molecular profile consistent with AD support the hypothesis that APOE genotype modulates the clinical phenotype of AD through influence on specific large-scale brain networks.

  7. The effects of direct thrombin inhibition with dabigatran on plaque formation and endothelial function in apolipoprotein E-deficient mice.

    PubMed

    Lee, Illkyu-O; Kratz, Mario T; Schirmer, Stephan H; Baumhäkel, Magnus; Böhm, Michael

    2012-11-01

    The recently developed oral anticoagulant dabigatran (Dabi) etexilate directly inhibits thrombin after activation by plasma esterases to dabigatran. Thrombin is involved in the pathogenesis of atherosclerosis. We investigated the effects of direct thrombin inhibition on atherosclerosis and endothelial function in a hypercholesterolemic mouse model with accelerated atherosclerosis {[apolipoprotein E-deficient (ApoE(-/-)] mice}. ApoE(-/-) mice were treated with a cholesterol-rich diet for 12 weeks and either dabigatran etexilate (900 mg/kg body weight) or vehicle. Wild-type (C57/B6) mice served as control. Endothelial function was assessed with carbachol (endothelium dependent) by using glyceroltrinitrate (endothelium independent) as control in aortic rings. Atherosclerotic lesion formation was evaluated with Oil Red staining, and vascular collagen content was determined by Sirius Red staining. Reactive oxygen species (ROS) production was determined by semiquantitative immunohistochemical staining. Measurement of dabigatran plasma levels (622.3±169 ng/ml) and a performed coagulation test (diluted thrombin time) revealed a relevant anticoagulatory concentration. Dabigatran etexilate attenuated increased atherosclerotic plaque formation [ApoE(-/-) Dabi: 16.1±3.8% of ApoE(-/-) control; p<0.001], decreased collagen content [ApoE(-/-) Dabi: 49.1±10% of ApoE(-/-) control; p=0.01], and ROS production in dihydroethidium staining [ApoE(-/-) Dabi: 46.3±5.4% of ApoE(-/-) control; p=0.005] in parallel to an improvement of endothelial function [ApoE(-/-) control 42.6±2.7 versus ApoE(-/-) Dabi 62.9±3.3% of phenylephrine-induced contraction; p=0.001] at 100 μmol carbachol. These data suggest that direct thrombin inhibition in a relevant dosage improved endothelial function and reduced atherosclerotic lesion size, collagen content, and oxidative stress in hypercholesterolemic atherosclerosis. Interference with the coagulation system might provide a therapeutic target to

  8. The relation between apolipoprotein E (APOE) genotype and peripheral artery disease in patients at high risk for cardiovascular disease.

    PubMed

    Koopal, Charlotte; Geerlings, Mirjam I; Muller, Majon; de Borst, G J; Algra, Ale; van der Graaf, Yolanda; Visseren, Frank L J

    2016-03-01

    The apolipoprotein E gene (APOE) is associated with coronary heart disease and stroke, but the relation with peripheral artery disease (PAD) is unknown. We investigated the relation of APOE genotype with PAD and other types of vascular disease. The cross-sectional association between APOE genotype and ankle-brachial index (ABI) and vascular disease prevalence; and the prospective relation with incident PAD and other types of vascular disease (coronary artery disease, stroke and vascular mortality) were evaluated in 7418 patients from the Secondary Manifestations of ARTerial disease (SMART) study. This is a prospective cohort study in patients with cardiovascular disease or a cardiovascular risk factor. Analyses were adjusted for age and sex. Mean age was 56.7 ± 12.4 years and 68% of the patients was male. APOE genotype frequencies were ε2ε2 1.3%; ε2ε3 9.9%; ε2ε4 2.4%; ε3ε3 56.9%; ε3ε4 26.7% and ε4ε4 2.8%. Median follow-up time was 8.1 years (IQR 5.4-11.4) in which 452 new PAD events occurred. The ε2ε2 genotype was significantly associated with a lower ABI (regression coefficient -0.04, 95%CI -0.07 to -0.01), increased PAD prevalence (prevalence ratio 1.54, 95%CI 1.01-2.17) and a higher risk of incident PAD (HR 2.31, 95%CI 1.29-4.12) compared with ε3ε3. No relations between APOE genotypes and other vascular disease were observed. Of the six APOE genotypes, the ε2ε2 variant is associated with an increased risk for PAD in patients at high risk for cardiovascular disease. No association was observed between APOE genotype and coronary artery disease, stroke or vascular mortality in this population. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Inhibition of extracellular cyclophilins with cyclosporine analog and development of atherosclerosis in apolipoprotein E-deficient mice.

    PubMed

    Ditiatkovski, Michael; Neelisetti, Vijaya N L V; Cui, Huanhuan L; Malesevic, Miroslav; Fischer, Gunter; Bukrinsky, Michael; Sviridov, Dmitri

    2015-06-01

    Cyclophilins exert both intracellular and extracellular activities related to immune responses and inflammation, which have been implicated in pathogenesis of atherosclerosis. Pan-inhibition of cyclophilins has both pro- and antiatherosclerotic properties, but specific contributions of extracellular and intracellular cyclophilins to these effects have not been characterized. Here, using selective inhibitor of extracellular cyclophilins, we investigated the role of these molecules in atherosclerosis. Apolipoprotein E-null mice fed a high-fat diet received intraperitoneal injections every second day of either vehicle or two analogs of cyclosporine A (CsA): [Melle](4)-CsA (NIM811), a nonimmunosupressive cell-permeable inhibitor of both intracellular and extracellular cyclophilins; and [(4R)-4-[(6-carboxy-1H-benzo[d]imidazol-2-yl)-methyl]-4-methyl-l-threonine](1)-CsA (MM284), cell-impermeable analog only inhibiting extracellular cyclophilins. Development of atherosclerosis and composition of plaques in aorta and innominate artery were studied. Both analogs increased abundance and cross-sectional size of the atherosclerotic plaques in aorta but did not affect development of atherosclerosis in innominate artery. Neither compound affected abundance of macrophages and amount of vascular cell adhesion molecule-1 or nitrotyrosine in the plaques of both arteries. Both compounds reduced the amount of collagen in innominate artery without affecting abundance of collagen in aortic sinus. MM284, but not NIM811, significantly reduced plasma concentration of tumor necrosis factor-α (TNFα); neither compound affected plasma concentrations of interleukin (IL)-6, IL-10 or monocyte chemoattractant protein-1. Ratio between different populations of immune cells in blood or isolated from lymph nodes and spleen as well as plasma lipoprotein profile were unaffected by both compounds. In conclusion, selective inhibition of extracellular cyclophilins reduced TNFα levels in plasma but

  10. CEREBRAL ATROPHY, APOLIPOPROTEIN E ε4, AND RATE OF DECLINE IN EVERYDAY FUNCTION AMONG PATIENTS WITH AMNESTIC MILD COGNITIVE IMPAIRMENT

    PubMed Central

    Okonkwo, Ozioma C.; Alosco, Michael L.; Jerskey, Beth A.; Sweet, Lawrence H.; Ott, Brian R.; Tremont, Geoffrey

    2010-01-01

    BACKGROUND Patients with amnestic mild cognitive impairment (MCI) demonstrate decline in everyday function. In this study, we investigated whether whole brain atrophy and apolipoprotein E (APOE) genotype are associated with the rate of functional decline in MCI. METHODS Participants were 164 healthy controls, 258 MCI patients, and 103 patients with mild Alzheimer’s disease (AD), enrolled in the Alzheimer’s Disease Neuroimaging Initiative (ADNI). They underwent brain MRI scans, APOE genotyping, and completed up to 6 biannual Functional Activities Questionnaire (FAQ) assessments. Random effects regressions were used to examine trajectories of decline in FAQ across diagnostic groups, and to test the effects of ventricle-to-brain ratio (VBR) and APOE genotype on FAQ decline among MCI patients. RESULTS Rate of decline in FAQ among MCI patients was intermediate between that of controls and mild AD patients. Patients with MCI who converted to mild AD declined faster than those who remained stable. Among MCI patients, increased VBR and possession of any APOE ε4 allele were associated with faster rate of decline in FAQ. In addition, there was a significant VBR by APOE ε4 interaction such that patients who were APOE ε4 positive and had increased atrophy experienced the fastest decline in FAQ. CONCLUSIONS Functional decline occurs in MCI, particularly among patients who progress to mild AD. Brain atrophy and APOE ε4 positivity are associated with such declines, and patients who have elevated brain atrophy and are APOE ε4 positive are at greatest risk of functional degradation. These findings highlight the value of genetic and volumetric MRI information as predictors of functional decline, and thus disease progression, in MCI. PMID:20813341

  11. Copper Chelation by Tetrathiomolybdate Inhibits Vascular Inflammation and Atherosclerotic Lesion Development in Apolipoprotein E-deficient Mice

    PubMed Central

    Wei, Hao; Zhang, Wei-Jian; Mcmillen, Timothy S.; Leboeuf, Renee C.; Frei, Balz

    2012-01-01

    Endothelial activation, which is characterized by upregulation of cellular adhesion molecules and pro-inflammatory chemokines and cytokines, and consequent monocyte recruitment to the arterial intima are etiologic factors in atherosclerosis. Redox-active transition metal ions, such as copper and iron, may play an important role in endothelial activation by stimulating redox-sensitive cell signaling pathways. We have shown previously that copper chelation by tetrathiomolybdate (TTM) inhibits LPS-induced acute inflammatory responses in vivo. Here, we investigated whether TTM can inhibit atherosclerotic lesion development in apolipoprotein E-deficient (apoE−/−) mice. We found that 10-week treatment of apoE−/− mice with TTM (33–66 ppm in the diet) reduced serum levels of the copper-containing protein, ceruloplasmin, by 47%, and serum iron by 26%. Tissue levels of “bioavailable” copper, assessed by the copper-to-molybdenum ratio, decreased by 80% in aorta and heart, whereas iron levels of these tissues were not affected by TTM treatment. Furthermore, TTM significantly attenuated atherosclerotic lesion development in whole aorta by 25% and descending aorta by 45% compared to non-TTM treated apoE−/− mice. This anti-atherogenic effect of TTM was accompanied by several anti-inflammatory effects, i.e., significantly decreased serum levels of soluble vascular cell and intercellular adhesion molecules (VCAM-1 and ICAM-1); reduced aortic gene expression of VCAM-1, ICAM-1, monocyte chemotactic protein-1, and pro-inflammatory cytokines; and significantly less aortic accumulation of M1 type macrophages. In contrast, serum levels of oxidized LDL were not reduced by TTM. These data indicate that TTM inhibits atherosclerosis in apoE−/− mice by reducing bioavailable copper and vascular inflammation, not by altering iron homeostasis or reducing oxidative stress. PMID:22770994

  12. Nuclear microprobe investigation into the trace elemental contents of carotid artery walls of apolipoprotein E deficient mice

    NASA Astrophysics Data System (ADS)

    Minqin, Ren; En, Huang; Beck, Konstanze; Rajendran, Reshmi; Wu, Ben J.; Halliwell, Barry; Watt, Frank; Stocker, Roland

    2007-07-01

    Atherosclerosis is a progressive disease that causes lesions in large and medium-sized arteries. There is increasing evidence that the function of vascular endothelial cells is impaired by oxidation reactions, and that metal ions may participate in these processes. The nuclear microscopy facility in NUS, which has the ability to focus a 2 MeV proton beam down to sub micron spot sizes, was used to investigate the trace elemental changes (e.g. Zn and Fe) in atherosclerotic lesions in the common carotid artery of apolipoprotein E deficient mice fed a high fat diet. In this preliminary study, which is part of a larger study to investigate the effects of probucol on carotid artery atherosclerosis, two sets of mice were used; a test set fed a high fat diet +1% probucol, and a control set which was fed a high fat diet only. The results show that the Zn/Fe ratio was significantly higher in the media of arteries of probucol treated animals without overlying lesion (4.3) compared to the media with overlying lesion (1.3) ( p = 0.004) for test mice. For the control mice, the arterial Zn/Fe ratio was 1.8 for media without overlying lesion, compared with 1.0 for media with overlying lesion ( p = 0.1). Thus, for media without overlying lesion, the Zn/Fe ratio was significantly higher ( p = 0.009) in probucol-treated (4.3) than control mice (1.8), whereas there was little difference in the ratios between the two groups in media with overlying lesion (1.3 compared with 1.0). These preliminary results are consistent with the idea that the levels of iron and zinc concentrations within the artery wall may influence the formation of atherosclerotic plaque in the carotid artery.

  13. Both Targeted Mass Spectrometry and Flow Sorting Analysis Methods Detected the Decreased Serum Apolipoprotein E Level in Alzheimer's Disease Patients*

    PubMed Central

    Han, Sun-Ho; Kim, Jun Seok; Lee, Youngju; Choi, Heesun; Kim, Jong-Won; Na, Duk Lyul; Yang, Eun Gyeong; Yu, Myeong-Hee; Hwang, Daehee; Lee, Cheolju; Mook-Jung, Inhee

    2014-01-01

    Apolipoprotein E (ApoE) polymorphism has been appreciated as a valuable predictor of Alzheimer disease (AD), and the associated ε4 allele has been recognized as an indicator of susceptibility to this disease. However, serum ApoE levels have been a controversial issue in AD, due to the great variability regarding the different target detection methods, ethnicity, and the geographic variations of cohorts. The aim of this study was to validate serum ApoE levels in relation to AD, particularly using two distinct detection methods, liquid chromatography–selected reaction monitoring (SRM) mass spectrometry and microsphere-based fluorescence-activated cell sorting (FACS) analysis, to overcome experimental variations. Also, comparison of serum ApoE levels was performed between the level of protein detection by FACS and peptide level by SRM in both control and AD patients. Results from the two detection methods were cross-confirmed and validated. Both methods produced fairly consistent results, showing a significant decrease of serum ApoE levels in AD patients relative to those of a control cohort (43 control versus 45 AD, p < 0.0001). Significant correlation has been revealed between results from FACS and SRM (p < 0.0001) even though lower serum ApoE concentration values were measured in protein by FACS analysis than in peptide-level detections by SRM. Correlation study suggested that a decrease of the serum ApoE level i