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Sample records for apolipoprotein-e forms dimers

  1. 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

  2. Alzheimer amyloid-beta peptide forms denaturant-resistant complex with type epsilon 3 but not type epsilon 4 isoform of native apolipoprotein E.

    PubMed Central

    Zhou, Z.; Smith, J. D.; Greengard, P.; Gandy, S.

    1996-01-01

    BACKGROUND: The apolipoprotein E (apoE) type epsilon 4 isoform specifies increased cerebral and cerebrovascular accumulation of amyloid-beta protein (A beta) and contributes to the genetic susceptibility underlying a large proportion (approximately 60%) of typical, sporadic Alzheimer disease. Unfortunately, in vitro biochemical studies of direct apoE isoform-specific interactions with A beta have been inconsistent, perhaps due to the use by different research groups of apoE isoform preparations in different conformational states (purified denatured versus native). MATERIALS AND METHODS: In the current study, we have investigated the possibility that synthetic A beta(1-40) preferentially associates with native apoE of either the type epsilon 3 or the type epsilon 4 isoform. RESULTS: Here, we demonstrate the preferential association of synthetic A beta(1-40) with native apoE epsilon 3. The complex between apoE epsilon 3 and A beta(1-40) could not be disrupted by sodium dodecyl sulfate. In a parallel assay, no denaturant-resistant association of A beta(1-40) with apoE epsilon 4 was detectable. CONCLUSIONS: These results support the notion that the apoE epsilon 4 isoform may foster beta-amyloidogenesis because apoE epsilon 4 is inefficient in forming complexes with A beta. Images FIG. 1 FIG. 2 PMID:8726460

  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. PMID:18805361

  5. Extrahepatic synthesis of apolipoprotein E

    SciTech Connect

    Driscoll, D.M.; Getz, G.S.

    1984-12-01

    Apolipoprotein E (apoE) synthesis has been examined in rat and guinea pig tissues using in vitro translation and (/sup 35/S)methionine labeling of tissue slices. A number of tissues not involved in lipoprotein synthesis synthesize a protein very similar to apoE, including the spleen, adrenal, kidney, testis, ovary, heart, and lung. Although the intestine is involved in lipoprotein synthesis, apoE synthesis could not be detected in intestinal mucosa. The protein synthesized by the extrahepatic tissues was identified as apoE by its electrophoretic mobility, its immunologic reactivity with a monospecific antibody and by limited proteolysis mapping with Staphylococcus aureus V8 protease. ApoE represented between 0.02 and 0.7% of the total protein synthesized in the extrahepatic tissues, indicating that apoE mRNA is a fairly abundant mRNA in these tissues. ApoE mRNA was also detected by hybridization with a rat apoE cDNA clone, which hybridized to a single mRNA 1250 nucleotides in length in rat liver and in extrahepatic tissues. Hybridization of the apoE clone to rat genomic DNA demonstrated that the apoE gene was more heavily methylated in intestinal mucosa, which did not synthesize apoE, than in liver, testis, or kidney. /sup 35/S labeling of peritoneal macrophages revealed that both rat and guinea pig macrophages synthesized and secreted apoE in vitro. Rhesus aortic smooth muscle cells also synthesized and secreted apoE. The possible functions of apoE synthesized in the peripheral tissues are considered.

  6. 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.

  7. 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

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

    PubMed

    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

    2016-07-01

    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. 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. PMID:26923007

  10. Apolipoprotein E isoform-dependent microglia migration

    PubMed Central

    Cudaback, Eiron; Li, Xianwu; Montine, Kathleen S.; Montine, Thomas J.; Keene, C. Dirk

    2011-01-01

    Complement component C5a and ATP are potent effectors of microglial movement and are increased in diverse neurodegenerative diseases and at sites of injury. Apolipoprotein E (apoE) influences microglial function, and different human apoE isoforms confer variable risk for development of neurodegenerative disorders, especially Alzheimer's disease. The purpose of this investigation was to test the hypothesis that mouse apoE and human apoE isoforms influence microglial migration. Using primary wild-type and apoE-deficient microglia, we show that C5a- and ATP-stimulated chemotaxis are largely apoE-dependent processes with different molecular bases. Although the C5a-dependent chemotaxis of wild-type microglia was completely blocked by receptor-associated protein (RAP), suggesting apoE receptor involvement, ATP-stimulated migration was unaffected by RAP but was associated with differential ERK phosphorylation. Studies using primary microglia derived from targeted replacement mice “humanized” for the coding exons (protein isoform) of human ε2 (apoE2), ε3 (apoE3), or ε4 (apoE4) allele of APOE revealed that primary mouse microglia expressing apoE4 or apoE2 exhibited significantly reduced C5a- and ATP-stimulated migration compared with microglia expressing human apoE3. This study, for the first time, demonstrates apoE dependence and apoE isoform-specific modulation of microglial migration in response to distinct chemotactic stimuli commonly associated with neurodegenerative disease.—Cudaback, E., Li, X., Montine, K. S., Montine, T. J., Keene, C. D. Apolipoprotein E isoform-dependent microglia migration. PMID:21385991

  11. 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.

  12. 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

  13. Apolipoprotein E: Risk factor for Alzheimer disease

    SciTech Connect

    Tsai, M.S.; Thibodeau, S.N.; Tangalos, E.G.; Petersen, R.C.; Kokmen, E.; Smith, G.E.; Schaid, D.J.; Ivnik, R.J. )

    1994-04-01

    The apolipoprotein E gene (APOE) has three common alleles (E2, E3, and E4) that determine six genotypes in the general population. In this study, the authors examined 77 patients with late-onset Alzheimer disease (AD), along with an equal number of age- and sex-matched controls, for an association with the APOE-E4 allele. They show that the frequency of this allele among AD patients was significantly higher than that among the control population (.351 vs. .130, P = .000006). The genotype frequencies also differed between the two groups (P = .0002), with the APOE-E4/E3 genotype being the most common in the AD group and the APOE-E3/E3 being the most common in the control group. In the AD group, homozygosity for E4 was found in nine individuals, whereas none was found in the control group. The odds ratio for AD, when associated with one or two E4 alleles, was 4.6 (95% confidence interval [CI] 1.9-12.3), while the odds ratio for AD, when associated with heterozygosity for APOE-E4, was 3.6 (05% CI 1.5-9.8). Finally, the median age at onset among the AD patients decreased from 83 to 78 to 74 years as the number of APOE-E4 alleles increased from 0 to 1 to 2, respectively (test for trend, P = .001). The data, which are in agreement with recent reports, suggest that the APOE-E4 allele is associated with AD and that this allelic variant may be an important risk factor for susceptibility to AD in the general population. 30 refs., 5 tabs.

  14. Non-apolipoprotein E and apolipoprotein E genetics of sporadic Alzheimer's disease.

    PubMed

    Seripa, Davide; Panza, Francesco; Franceschi, Marilisa; D'Onofrio, Grazia; Solfrizzi, Vincenzo; Dallapiccola, Bruno; Pilotto, Alberto

    2009-07-01

    The genetic epidemiology of sporadic Alzheimer's disease (SAD) remains a very active area of research,making it one of the most prolifically published areas in medicine and biology. Numerous putative candidate genes have been proposed. However, with the exception of apolipoprotein E (APOE), the only confirmed genetic risk factor for SAD, all the other data appear to be not consistent. Nevertheless, the genetic risk for SAD attributable to the APOE gene in the general population is 20-0%, providing a strong evidence for the existence of additional genetic risk factors. The first part of the present article was dedicated to non-APOE genetics of SAD, reviewing chromosomes-by-chromosomes the available data concerning the major candidate genes. The second part of this article focused on some recently discovered aspects of the APOE polymorphism and their implications for SAD. An attempt to identify the future directions for non-APOE genetic research in SAD was also discussed. PMID:19496238

  15. A dimeric form of prothrombin on membrane surfaces.

    PubMed Central

    Anderson, P J

    1998-01-01

    Blood coagulation requires the conversion of zymogens to active enzymes. These reactions are facilitated by Ca2+-dependent protein binding to membrane surfaces containing anionic phospholipids. Here it is shown that only in the presence of both Ca2+ and phospholipid vesicles composed of phosphatidylcholine and phosphatidylserine can a prothrombin dimer be chemically cross-linked. A cross-linker containing evenly spaced reactive groups was prepared by activating the carboxy groups of a ten-residue glutamic acid peptide and allowed to react with physiological concentrations of prothrombin. When Ca2+ and anionic phospholipids were both present during exposure to the cross-linker, it was found that more than 50% of the prothrombin was trapped as a chemically defined dimer with reaction times of the order of 1 min. The dimer yield remained high even when reactions were performed at high phospholipid-to-protein ratios at protein concentrations an order of magnitude less than physiological. Amino acid sequencing of a CNBr peptide produced from the purified dimer localized the cross-link to residues Lys341 and Lys427 of prothrombin. The specificity and high yield under mild conditions of the cross-linking suggest that dimeric membrane bound prothrombin might be a physiologically relevant substrate for the formation of thrombin. Prothrombinase converts this modified protein to an enzyme that catalyses the hydrolysis of a thrombin chromogenic substrate as efficiently as thrombin and is inhibited by a thrombin active-site directed inhibitor, but is a thrombin dimer. The thrombin dimer has impaired activity compared with thrombin with respect to physiological functions requiring binding to exosite I. A model based on the known structure of thrombin is presented that can account for the prothrombin dimer and the properties of the dimeric thrombin formed from it. PMID:9841875

  16. APOLIPOPROTEIN E GENE AND EARLY AGE-RELATED MACULOPATHY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    OBJECTIVE: To examine the association between the apolipoprotein E (APOE) gene and early age-related maculopathy (ARM) in middle-aged persons. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Participants from the Atherosclerosis Risk in Communities Study (n = 10139; age range, 49-73 ye...

  17. 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. PMID:26519632

  18. 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

  19. 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

  20. Apolipoprotein E alleles in women with severe pre-eclampsia.

    PubMed Central

    Nagy, B; Rigó, J; Fintor, L; Karádi, I; Tóth, T

    1998-01-01

    This study investigated the frequency of apolipoprotein E (apoE) alleles among women with severe pre-eclampsia. The presence of the three most common apoE alleles (epsilon 2, epsilon 3, epsilon 4) was determined by polymerase chain reaction-restriction fragment length polymorphism in three groups of white women: non-pregnant healthy (n = 101), pregnant healthy (n = 52), and pregnant with a diagnosis of severe pre-eclampsia (n = 54). The frequency of apo epsilon 2 was highest among women with severe pre-eclampsia (16.6%) followed by non-pregnant women (12.9%), and those experiencing a healthy pregnancy (10.6%). The higher frequency of the apo epsilon 2 allele detected among women with severe pre-eclampsia suggests that apoE may play a role in the development of pre-eclampsia. PMID:9659248

  1. Function and Comorbidities of Apolipoprotein E in Alzheimer's Disease

    PubMed Central

    Leduc, Valérie; Domenger, Dorothée; De Beaumont, Louis; Lalonde, Daphnée; Bélanger-Jasmin, Stéphanie; Poirier, Judes

    2011-01-01

    Alzheimer's disease (AD)—the most common type of dementia among the elderly—represents one of the most challenging and urgent medical mysteries affecting our aging population. Although dominant inherited mutation in genes involved in the amyloid metabolism can elicit familial AD, the overwhelming majority of AD cases, dubbed sporadic AD, do not display this Mendelian inheritance pattern. Apolipoprotein E (APOE), the main lipid carrier protein in the central nervous system, is the only gene that has been robustly and consistently associated with AD risk. The purpose of the current paper is thus to highlight the pleiotropic roles and the structure-function relationship of APOE to stimulate both the functional characterization and the identification of novel lipid homeostasis-related molecular targets involved in AD. PMID:21559182

  2. Apolipoprotein E is a kinetic but not a thermodynamic inhibitor of amyloid formation: implications for the pathogenesis and treatment of Alzheimer disease.

    PubMed Central

    Evans, K C; Berger, E P; Cho, C G; Weisgraber, K H; Lansbury, P T

    1995-01-01

    The apolipoprotein E4 (APOE4) allele is associated with an early age of onset of the nonfamilial form of Alzheimer disease (AD) and with increased beta protein amyloid deposition in the brain. These two observations may both arise from an effect of the apoE family of proteins on the rate of in vivo amyloidogenesis. We report here that apoE3, the common apoE isoform, is an in vitro amyloid nucleation inhibitor at physiological concentrations. A significant delay in the onset of amyloid fibril formation by the beta-amyloid protein of AD (beta 1-40) was observed at a low apoE3 concentration (40 nM), corresponding to an apoE3/beta protein molar ratio of 1:1000. The inhibitory activity of a proteolytic fragment of apoE3, containing the N-terminal 191 amino acids, is comparable to the native protein, whereas the C-terminal fragment has no activity. ApoE4 is equipotent or slightly less potent than apoE3, which may be due to its inability to form a disulfide dimer, since the apoE3 dimer is a significantly more potent nucleation inhibitor than apoE4. Neither apoE3 nor apoE4 inhibits the seeded growth of amyloid or affects the solubility or structure of the amyloid fibrils, indicating that apoE is not a thermodynamic amyloid inhibitor. We propose that the linkage between the APOE4 allele and AD reflects the reduced ability of APOE4 homozygotes to suppress in vivo amyloid formation. Images Fig. 4 PMID:7846048

  3. Electrooptics of chiral nematics formed by molecular dimers

    NASA Astrophysics Data System (ADS)

    Xiang, Jie; Shiyanovskii, Sergij V.; Li, Yannian; Imrie, Corrie T.; Li, Quan; Lavrentovich, Oleg D.

    2014-10-01

    Electrically induced reorientation of liquid crystal (LC) director caused by dielectric anisotropy is a fundamental phenomenon widely used in modern technologies. We demonstrate an electrooptic effect in a chiral nematic LC with a distinct oblique-helicoidal director deformation. The effect, predicted theoretically in late 1960-ies, is observed in a chiral nematic (cholesteric) in which the ground field-free state of the director is a right-angle helicoid. In the electric field, the director forms an oblique helicoid with the pitch and cone angle controlled by the field. The effect is observed in a dimer nematic material in which the bend elastic constant is much smaller than its twist counterpart. The heliconical structure can be used in two different geometries of a sandwich-type cell, with the axis of the oblique helicoid being either parallel or perpendicular to the bounding plates. In the first case, the structure can be used as tunable diffraction grating controlled by the in-plane electric field. In the second case, the structure represents an optical Bragg reflector in which the wavelength of reflected light is controlled in a broad spectral range (from ultraviolet to infrared and beyond, depending on the composition) by a top-down electric field; it can find applications in reflective displays, tunable color filters and lasers.

  4. The Apolipoprotein E Gene, Attention, and Brain Function

    PubMed Central

    Parasuraman, Raja; Greenwood, Pamela M.; Sunderland, Trey

    2005-01-01

    The ɛ4 allele of the apolipoprotein E (ApoE) gene is associated with alterations in brain function and is a risk factor for Alzheimer’s disease (AD). Changes in components of visuospatial attention with ApoE-ɛ4, aging, and AD are described. Healthy middle-aged adults without dementia who have the ApoE-ɛ4 gene show deficits in spatial attention and working memory that are qualitatively similar to those seen in clinically diagnosed AD patients. The findings support an association between ApoE polymorphism and specific components of visuospatial attention. Molecular mechanisms that may mediate the ApoE–attention link by modulating cholinergic neurotransmission to the posterior parietal cortex are discussed. Studies of attention and brain function in ApoE-ɛ4 carriers without dementia can advance knowledge of the genetics of visual attention, may enhance understanding of the preclinical phase of AD, and may lead to better methods for early AD detection. PMID:11949718

  5. Acetylcholine receptor and behavioral deficits in mice lacking apolipoprotein E

    PubMed Central

    Siegel, Jessica A; Benice, Theodore S; Van Meer, Peter; Park, Byung S; Raber, Jacob

    2011-01-01

    Apolipoprotein E (apoE) is involved in the risk to develop sporadic Alzheimer’s disease (AD). Since impaired central acetylcholine (ACh) function is a hallmark of AD, apoE may influence ACh function by modulating muscarinic ACh receptors (mAChRs). To test this hypothesis, mAChR binding was measured in mice lacking apoE and wild type C57BL/6J mice. Mice were also tested on the pre-pulse inhibition, delay eyeblink classical conditioning, and 5-choice serial reaction time tasks, which are all modulated by ACh transmission. Mice were also given scopolamine to challenge central mAChR function. Compared to wild type mice, mice lacking apoE had reduced number of cortical and hippocampal mAChRs. Scopolamine had a small effect on delay eyeblink classical conditioning in wild type mice but a large effect in mice lacking apoE. Mice lacking apoE were also unable to acquire performance on the 5-choice serial reaction time task. These results support a role for apoE in ACh function and suggest that modulation of cortical and hippocampal mAChRs might contribute to genotype differences in scopolamine sensitivity and task acquisition. Impaired apoE functioning may result in cholinergic deficits that contribute to the cognitive impairments seen in AD. PMID:19178986

  6. Association between apolipoprotein E gene polymorphism and depression.

    PubMed

    Feng, Fang; Lu, Shan-Shan; Hu, Cai-Yun; Gong, Feng-Feng; Qian, Zhen-Zhong; Yang, Hui-Yun; Wu, Yi-Le; Zhao, Yuan-Yuan; Bi, Peng; Sun, Ye-Huan

    2015-08-01

    We performed an updated meta-analysis to obtain a more precise estimation of the relationship between apolipoprotein E (ApoE) gene polymorphism and susceptibility to depression, as previous reports have been inconsistent. Twenty studies with 2286 depression patients and 3845 controls were included. Odds ratios (OR) with 95% confidence intervals (CI) were calculated to assess the association between ApoE gene polymorphism and depression using a random effects model. Results showed a significant association between ApoE gene polymorphism and susceptibility to depression in the overall population (ε2/ε3 genotype versus ε3/ε3: OR 0.76, 95% CI 0.59-0.99). Subgroup analyses indicated an association in the Caucasian population (ε2 allele versus ε3: OR 0.75, 95% CI 0.58-0.97) as well as in late-life depression (LLD) patients (ε3/ε4 genotype versus ε3/ε3: OR 1.34, 95% CI 1.07-1.68, and ε4 allele versus ε3: OR 1.30, 95% CI 1.06-1.59). We concluded that the ε2/ε3 genotype likely provided a protective effect against depression in the overall population and the ε2 allele acted as a protective factor for depression in the Caucasian population while the ε4 allele and ε3/ε4 genotype were associated with an increased risk of depression in the LLD subjects. PMID:25979253

  7. 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. PMID:23296339

  8. Regulation of endogenous apolipoprotein E secretion by macrophages.

    PubMed

    Kockx, Maaike; Jessup, Wendy; Kritharides, Leonard

    2008-06-01

    Apolipoprotein E has critical roles in the protection against atherosclerosis and is understood to follow the classical constitutive secretion pathway. Recent studies have indicated that the secretion of apoE from macrophages is a regulated process of unexpected complexity. Cholesterol acceptors such as apolipoprotein A-I, high density lipoprotein, and phospholipid vesicles can stimulate apoE secretion. The ATP binding cassette transporter ABCA1 is involved in basal apoE secretion and in lipidating apoE-containing particles secreted by macrophages. However, the stimulation of apoE secretion by apoA-I is ABCA1-independent, indicating the existence of both ABCA1-dependent and -independent pathways of apoE secretion. The release of apoE under basal conditions is also regulated, requiring intact protein kinase A activity, intracellular calcium, and an intact microtubular network. Mathematical modeling of apoE turnover indicates that whereas some pools of apoE are committed to either secretion or degradation, other pools can be diverted from degradation toward secretion. Targeted inhibition or stimulation of specific apoE trafficking pathways will provide unique opportunities to regulate the biology of this important molecule. PMID:18388328

  9. The Distribution of Apolipoprotein E Gene Polymorphism and Apolipoprotein E Levels among Coronary Artery Patients Compared to Controls

    PubMed Central

    Atis, Omer; Sahin, Semsettin; Ceyhan, Koksal; Ozyurt, Huseyin; Akbas, Ali; Benli, Ismail

    2016-01-01

    Objective: Coronary artery disease (CAD) is a multifactorial disease that is caused by various genetics and environmental factors. Genetically, predisposition is an important component for CAD. The candidate apolipoprotein E (apoE) gene is the most studied one. ApoE is composed of e2, e3, e4 alleles and E2/2, E2/3, E2/4, E3/3, E3/4, E4/4 genotypes. In this study, the relationship between CAD and apoE polymorphism and apoE level has been studied in Tokat region. Materials and Methods: The study population is composed of 100 CAD patients diagnosed by coronary angiography and 100 control patients of whom fifty have normal coronary angiography and fifty did not have any CAD symptoms. The serum lipid and apoE levels and apoE genotypes of all participants have been measured, and the relationship between these parameters has been evaluated. Results: Apolipoprotein E, total cholesterol, HDL cholesterol and LDL cholesterol levels were statistically low at CAD patients than control patients (p=0.0004, p=0.0005, p=0.0107, p=0.0052 respectively). There was not any significant difference between triglyceride levels (p=0.0848). Waist circumferences were significantly high at CAD patients (p=0.0012). Allele frequencies were as e2 (7.25%), e3 (83.5%), e4 (9.25%) and genotype distributions were as E2/2 (0.5%), E2/3 (13%), E2/4 (0.5%), E3/3 (68.5%), E3/4 (16.5%), E4/4 (1%). The distribution of alleles and genotypes were not significantly different (p>0.05). ApoE levels were higher at e2 allele carriers than e3 and e4 allele carriers (p<0.05). However, there was no significant difference between e3 and e4 allele carriers. Conclusion: In conclusion, the distribution of apoE genotype and allele at our region is similar to the general of Turkey. The low apoE levels in CAD patients may show the influence of apoE on CAD by local and systemic mechanisms. PMID:27551170

  10. 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.

  11. Apolipoprotein E isoform-specific effects on lipoprotein receptor processing

    PubMed Central

    Bachmeier, Corbin; Shackleton, Ben; Ojo, Joseph; Paris, Daniel; Mullan, Michael; Crawford, Fiona

    2014-01-01

    Recent findings indicate an isoform-specific role for apolipoprotein E (apoE) in the elimination of beta-amyloid (Aβ) from the brain. ApoE is closely associated with various lipoprotein receptors, which contribute to Aβ brain removal via metabolic clearance or transit across the blood-brain barrier (BBB). These receptors are subject to ectodomain shedding at the cell surface, which alters endocytic transport and mitigates Aβ elimination. To further understand the manner in which apoE influences Aβ brain clearance, these studies investigated the effect of apoE on lipoprotein receptor shedding. Consistent with prior reports, we observed an increased shedding of the low density lipoprotein receptor (LDLR) and the LDLR-related protein 1 (LRP1) following Aβ exposure in human brain endothelial cells. When Aβ was co-treated with each apoE isoform, there was a reduction in Aβ-induced shedding with apoE2 and apoE3, while lipoprotein receptor shedding in the presence of apoE4 remained elevated. Likewise, intracranial administration of Aβ to apoE targeted replacement mice (expressing the human apoE isoforms) resulted in an isoform-dependent effect on lipoprotein receptor shedding in the brain (apoE4>apoE3>apoE2). Moreover, these results show a strong inverse correlation with our prior work in apoE transgenic mice in which apoE4 animals showed reduced Aβ clearance across the BBB compared to apoE3 animals. Based on these results, apoE4 appears less efficient than other apoE isoforms in regulating lipoprotein receptor shedding, which may explain the differential effects of these isoforms in removing Aβ from the brain. PMID:25015123

  12. Heterogeneous expression of apolipoprotein-E by human macrophages

    PubMed Central

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

    2004-01-01

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

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

    PubMed

    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. PMID:26201081

  14. 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.

  15. Microcalcifications in atherosclerotic lesion of apolipoprotein E-deficient mouse

    PubMed Central

    Debernardi, Nicola; Roijers, Ruben B; Krams, Rob; de Crom, Rini; Mutsaers, Peter HA; van der Vusse, Ger J

    2010-01-01

    Evidence is accumulating that calcium-rich microdeposits in the vascular wall might play a crucial role in the onset and progression of atherosclerosis. Here we investigated an atherosclerotic lesion of the carotid artery in an established murine model, i.e. the apolipoprotein E-deficient (APOE−/−) mouse to identify (i) the presence of microcalcifications, if any, (ii) the elemental composition of microcalcifications with special reference to calcium/phosphorus mass ratio and (iii) co-localization of increased concentrations of iron and zinc with microcalcifications. Atherosclerosis was induced by a flow-divider placed around the carotid artery resulting in low and high shear-stress regions. Element composition was assessed with a proton microprobe. Microcalcifications, predominantly present in the thickened intima of the low shear-stress region, were surrounded by areas with normal calcium levels, indicating that calcium-precipitation is a local event. The diameter of intimal microcalcifications varied from 6 to 70 μm. Calcium/phosphorus ratios of microcalcifications varied from 0.3 to 4.8, mainly corresponding to the ratio of amorphous calcium-phosphate. Increased iron and zinc concentrations commonly co-localized with microcalcifications. Our findings indicate that the atherosclerotic process in the murine carotid artery is associated with locally accumulated calcium, iron and zinc. The calcium-rich deposits resemble amorphous calcium phosphate rather than pure hydroxyapatite. We propose that the APOE−/− mouse, in which atherosclerosis was evoked by a flow-divider, offers a useful model to investigate the pathophysiological significance of accumulation of elements such as calcium, iron and zinc. PMID:20804542

  16. 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. PMID:26519880

  17. Proteolytic Cleavage of Apolipoprotein E in the Down Syndrome Brain

    PubMed Central

    Day, Ryan J.; McCarty, Katie L.; Ockerse, Kayla E.; Head, Elizabeth; Rohn, Troy T.

    2016-01-01

    Down syndrome (DS) is one of the most common genetic causes of intellectual disability and is characterized by a number of behavioral as well as cognitive symptoms. Many of the neuropathological features of early-onset Alzheimer’s disease (AD) including senile plaques and neurofibrillary tangles (NFTs) are also present in people with DS as a result of triplication of the amyloid precursor gene on chromosome 21. Evidence suggests that harboring one or both apolipoprotein E4 (APOE4) alleles may increase the risk for AD due to the proteolytic cleavage of apoE4 and a subsequent loss of function. To investigate a role for the apoE proteolysis in vivo, we compared three autopsy groups; 7 DS with AD neuropathology cases over 40 years, 5 young DS cases without AD pathology under 40 years (YDS) and 5 age-matched control cases over 40 years by immunohistochemistry utilizing an antibody that detects the amino-terminal fragment of apoE. Application of this antibody, termed the amino-terminal apoE fragment antibody (nApoECF) revealed labeling of pyramidal neurons in the frontal cortex of YDS cases, whereas in the DS-AD group, labeling with nApoECF was prominent within NFTs. NFT labeling with nApoECF was significantly greater in the hippocampus versus the frontal cortex in the same DS-AD cases, suggesting a regional distribution of truncated apoE. Colocalization immunofluorescence experiments indicated that 52.5% and 53.2% of AT8- and PHF-1-positive NFTs, respectively, also contained nApoECF. Collectively, these data support a role for the proteolytic cleavage of apoE in DS and suggest that apoE fragmentation is closely associated with NFTs. PMID:27330841

  18. Working memory and apolipoprotein E: what's the connection?

    PubMed

    Rosen, V M; Bergeson, J L; Putnam, K; Harwell, A; Sunderland, T

    2002-01-01

    Two robust findings in the Alzheimer's literature are that patients with Alzheimer's disease (AD) show executive function and primacy deficits. The present study examined whether we would find similar deficits when comparing two groups of middle-aged individuals who differed with respect to genetic risk for AD, based on their apolipoprotein E (APOE) genotype. All individuals were screened as normal on a battery of standardized cognitive measures. They were tested on the "Operation span task", which engages the central executive component of working memory [J. Exp. Psychol.: Gen. 128 (1999) 309, J. Exp. Psychol.: Gen. 126 (1997) 211, J. Mem. Language 39 (1998) 418] by dividing attention between processing math operations and remembering words. Individuals were grouped according to APOE genotype ( epsilon 4 carrier versus epsilon 4 non-carrier), matched on age and education, and their Total span and Primacy scores were compared. Despite having no overt symptoms of dementia or deficits on a series of standardized psychometric tests, the epsilon 4 carriers showed divided-attention and primacy deficits on the Operation span task, when compared to the epsilon 4 non-carriers. As a point of comparison, Primacy scores were extracted from the first trial of the "Buschke selective reminding task" [J. Verbal Learn. Verbal Behav. 12 (1973) 543] for these same individuals, and no group differences were found. The Buschke task is a list-learning task that does not require divided attention. These findings suggested that the epsilon 4 carriers were less able to divide their attention, when compared to the epsilon 4 non-carriers. The findings provide the first direct evidence for a relationship between APOE genotype and cognitive performance on measures of divided attention and primacy with non-demented individuals who showed no cognitive impairments on standardized measures. PMID:12417453

  19. Proteolytic Cleavage of Apolipoprotein E in the Down Syndrome Brain.

    PubMed

    Day, Ryan J; McCarty, Katie L; Ockerse, Kayla E; Head, Elizabeth; Rohn, Troy T

    2016-05-01

    Down syndrome (DS) is one of the most common genetic causes of intellectual disability and is characterized by a number of behavioral as well as cognitive symptoms. Many of the neuropathological features of early-onset Alzheimer's disease (AD) including senile plaques and neurofibrillary tangles (NFTs) are also present in people with DS as a result of triplication of the amyloid precursor gene on chromosome 21. Evidence suggests that harboring one or both apolipoprotein E4 (APOE4) alleles may increase the risk for AD due to the proteolytic cleavage of apoE4 and a subsequent loss of function. To investigate a role for the apoE proteolysis in vivo, we compared three autopsy groups; 7 DS with AD neuropathology cases over 40 years, 5 young DS cases without AD pathology under 40 years (YDS) and 5 age-matched control cases over 40 years by immunohistochemistry utilizing an antibody that detects the amino-terminal fragment of apoE. Application of this antibody, termed the amino-terminal apoE fragment antibody (nApoECF) revealed labeling of pyramidal neurons in the frontal cortex of YDS cases, whereas in the DS-AD group, labeling with nApoECF was prominent within NFTs. NFT labeling with nApoECF was significantly greater in the hippocampus versus the frontal cortex in the same DS-AD cases, suggesting a regional distribution of truncated apoE. Colocalization immunofluorescence experiments indicated that 52.5% and 53.2% of AT8- and PHF-1-positive NFTs, respectively, also contained nApoECF. Collectively, these data support a role for the proteolytic cleavage of apoE in DS and suggest that apoE fragmentation is closely associated with NFTs. PMID:27330841

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

    PubMed

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

    2016-07-26

    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

  2. The regulatory domain of human tryptophan hydroxylase 1 forms a stable dimer.

    PubMed

    Zhang, Shengnan; Hinck, Cynthia S; Fitzpatrick, Paul F

    2016-08-01

    The three eukaryotic aromatic amino acid hydroxylases phenylalanine hydroxylase, tyrosine hydroxylase, and tryptophan hydroxylase have essentially identical catalytic domains and discrete regulatory domains. The regulatory domains of phenylalanine hydroxylase form ACT domain dimers when phenylalanine is bound to an allosteric site. In contrast the regulatory domains of tyrosine hydroxylase form a stable ACT dimer that does not bind the amino acid substrate. The regulatory domain of isoform 1 of human tryptophan hydroxylase was expressed and purified; mutagenesis of Cys64 was required to prevent formation of disulfide-linked dimers. The resulting protein behaved as a dimer upon gel filtration and in analytical ultracentrifugation. The sw value of the protein was unchanged from 2.7 to 35 μM, a concentration range over which the regulatory domain of phenylalanine hydroxylase forms both monomers and dimers, consistent with the regulatory domain of tryptophan hydroxylase 1 forming a stable dimer stable that does not undergo a monomer-dimer equilibrium. Addition of phenylalanine, a good substrate for the enzyme, had no effect on the sw value, consistent with there being no allosteric site for the amino acid substrate. PMID:27255998

  3. [Cooperative mechanism of phosphorylation of the monomeric and dimeric forms of inorganic pyrophosphatase from baker's yeast].

    PubMed

    Bakulevá, N P; Kasho, V N; Baĭkov, A A; Nazarova, T I; Avaeva, S M

    1982-07-01

    A comparative study of phosphorylation of native dimeric and artificial monomeric forms of inorganic pyrophosphatase and its fluoride-stabilized complex with PPi has been carried out. The maximal incorporation of Pi for the dimeric and monomeric proteins is 0.5 and 1 mole per mole of subunit, respectively. The saturation kinetic curves are suggestive of strong positive cooperative interactions. The value of the Hill coefficient (5.5) for the free dimeric enzyme drastically changes upon the active center blockage and/or transition to the monomeric enzyme. Acceleration of dephosphorylation induced by Pi in the presence of Mg2+ is observed only in the case of the dimeric protein. The data obtained indicate that phosphorylation of native dimeric pyrophosphatase occurs according to a "flip-flop" mechanism; the Pi binding in the active center exerts a strong influence on individual steps of the reaction. PMID:6126224

  4. A dimeric form of lipocortin-1 in human placenta.

    PubMed Central

    Pepinsky, R B; Sinclair, L K; Chow, E P; O'Brine-Greco, B

    1989-01-01

    We have characterized a 68 kDa lipocortin from human placenta that was identified as a covalently linked homodimer of lipocortin-1 by peptide mapping and sequence analysis. The site of cross-linking was localized within the 3 kDa N-terminal tail region, an exposed domain that contains the phosphorylation sites for protein tyrosine kinase and protein kinase C and is sensitive to proteolysis. Sequence analysis of the corresponding peptide revealed that glutamine-18 was modified, suggesting that the cross-link may be generated by a transglutaminase. By incubating lipocortin-1 with placental membranes and with labelled glycine ethyl ester we observed a Ca2+-dependent labelling of lipocortin-1 within the tail region, supporting this notion. Like lipocortin-1, the dimer inhibits phospholipase Ad2 activity, is a substrate for the epidermal-growth-factor (EGF) receptor/kinase, and display Ca2+-dependent binding to phosphatidylserine-containing vesicles. In preparations from human placenta the dimer is particularly abundant, accounting for approx. 20% of the lipocortin-1. Images Fig. 1. Fig. 2. Fig. 3. Fig. 5. Fig. 7. PMID:2532504

  5. Neurodegeneration in mice resulting from loss of functional selenoprotein P or its receptor apolipoprotein E receptor 2.

    PubMed

    Valentine, William M; Abel, Ty W; Hill, Kristina E; Austin, Lori M; Burk, Raymond F

    2008-01-01

    Selenoprotein P (Sepp1) is involved in selenium homeostasis. Mice with a deletion of Sepp1, replacement of it by the shortened form Sepp1(Delta240-361), or deletion of its receptor apolipoprotein E receptor 2 develop severe neurologic dysfunction when fed low-selenium diet. Because the brainstems of Sepp1(-/-) mice had been observed to contain degenerated axons, a study of these 3 strains was made under selenium-deficient and high-selenium (control) conditions. Selenium-deficient wild-type mice were additional controls. Serial sections of the brain were evaluated with amino cupric silver degeneration and anti-glial fibrillary acidic protein stains. All 3 strains with altered Sepp1 metabolism developed severe axonal injury when fed selenium deficient diet. This injury was mitigated by high-selenium diet and was absent from selenium-deficient wild-type mice. Injury was most severe in Sepp1(-/-) mice, with staining in at least 6 brain regions. Injury in Sepp1(Delta240-361) and apolipoprotein E receptor 2 mice was less severe and occurred only in areas injured in Sepp1(-/-) mice, suggesting a common selenium-related etiology. Affected brain regions were primarily associated with auditory and motor functions, consistent with the clinical signs. Those areas have high metabolic rates. We conclude that interference with Sepp1 function damages auditory and motor areas, at least in part by restricting selenium supply to the brain regions. PMID:18172410

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

    PubMed

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

    2013-07-01

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

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

    PubMed

    Salameh, Therese S; Rhea, Elizabeth M; Banks, William A; Hanson, Angela J

    2016-09-01

    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

  8. The role of apolipoprotein E and glucose intolerance in gallstone disease in middle aged subjects

    PubMed Central

    Niemi, M; Kervinen, K; Rantala, A; Kauma, H; Paivansalo, M; Savolainen, M; Lilja, M; Kesaniemi, Y

    1999-01-01

    BACKGROUND—The polymorphism of apolipoprotein E has been suggested to be associated with the cholesterol content of gallstones, the crystallisation rate of gall bladder bile, and the prevalence of gallstone disease (GSD). 
AIMS—To investigate whether apolipoprotein E polymorphism modulates the susceptibility to GSD at the population level and to study the possible associations between impaired glucose tolerance, diabetes, and GSD. 
METHODS—Apolipoprotein E phenotypes were determined in a middle aged cohort of 261 randomly selected hypertensive men, 259 control men, 257 hypertensive women, and 267 control women. All subjects without a documented history of diabetes were submitted to a two hour oral glucose tolerance test (OGTT). GSD was verified by ultrasonography. 
RESULTS—In women with apolipoprotein E2 (phenotypes E2/2, 2/3, and 2/4) compared with women without E2 (E3/3, 4/3, and 4/4), the odds ratio for GSD was 0.28 (95% confidence interval 0.08-0.92). There was no protective effect in men. The relative risk for GSD was 1.2 (0.8-1.7) for hypertensive women and 1.8(1.0-2.7) for hypertensive men. In a stepwise multiple logistic regression model, E2 protected against GSD in women, whereas two hour blood glucose in the OGTT, serum insulin, and plasma triglycerides were risk factors. Elevated blood glucose during the OGTT was also a significant risk factor for GSD in men. 
CONCLUSIONS—The data suggest that apolipoprotein E2 is a genetic factor providing protection against GSD in women. In contrast, impaired glucose tolerance and frank diabetes are associated with the risk of GSD. 

 Keywords: apolipoprotein E; gallstone disease; diabetes; impaired glucose tolerance; cholesterol PMID:10075965

  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 GENOTYPE AND INCIDENT ISCHEMIC STROKE: THE ATHEROSCLEROSIS RISK IN COMMUNITY STUDY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    BACKGROUND AND PURPOSE: A relationship between the apolipoprotein E (apoE) genotype and ischemic stroke has been inconsistently reported. We explored this relation in the Atherosclerosis Risk in Communities Study (ARIC). METHODS: The ARIC cohort involves 15,792 men and women, aged 45 to 64 years at ...

  11. APOLIPOPROTEIN E GENE POLYMORPHISMS ARE NOT ASSOCIATED WITH DIABETIC RETINOPATHY: THE ATHEROSCLEROSIS RISK IN COMMUNITIES STUDY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    PURPOSE: Polymorphism of the apolipoprotein E (APOE) gene has been associated with dyslipidemia and cardiovascular disease. This study examines the association of APOE polymorphisms and diabetic retinopathy. DESIGN: Population-based cross-sectional study. METHODS: We studied 1,398 people aged 49 to ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  13. Apolipoprotein E includes a binding site which is recognized by several amyloidogenic polypeptides.

    PubMed Central

    Baumann, M H; Kallijärvi, J; Lankinen, H; Soto, C; Haltia, M

    2000-01-01

    Inheritance of the apolipoprotein E (apoE) epsilon 4 allele is a risk factor for late-onset Alzheimer's disease (AD). Biochemically apoE is present in AD plaques and neurofibrillary tangles of the AD brain. There is a high avidity and specific binding of apoE and the amyloid beta-peptide (A beta). In addition to AD apoE is also present in many other cerebral and systemic amyloidoses, Down's syndrome and prion diseases but the pathophysiological basis for its presence is still unknown. In the present study we have compared the interaction of apoE with A beta, the gelsolin-derived amyloid fragment AGel(183-210) and the amyloidogenic prion fragments PrP(109-122) and PrP(109-141). We show that, similar to A beta, also AGel and PrP fragments can form a complex with apoE, and that the interaction between apoE and the amyloidogenic protein fragments is mediated through the same binding site on apoE. We also show that apoE increases the thioflavin-T fluorescence of PrP and AGel and that apoE influences the content of beta-sheet conformation of these amyloidogenic fragments. Our results indicate that amyloids and amyloidogenic prion fragments share a similar structural motif, which is recognized by apoE, possibly through a single binding site, and that this motif is also responsible for the amyloidogenicity of these fragments. PMID:10861213

  14. 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

  15. 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. PMID:20092811

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

    NASA Astrophysics Data System (ADS)

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

    1985-02-01

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

  17. Cyclopropenium Cations Break the Rules of Attraction to Form Closely Bound Dimers.

    PubMed

    Wallace, Andrew J; Jayasinghe, Chaminda D; Polson, Matthew I J; Curnow, Owen J; Crittenden, Deborah L

    2015-12-16

    The crystal structures of tris(ethylmethylamino)-cyclopropenium chloride and tris(diethylamino)-cyclopropenium iodide reveal the presence of closely bound dicationic dimers formed from two closed-shell monomer units. The distances between the C3 centroids of the staggered monomers are at the short end of those normally found in π-stacked neutral arenes, let alone charged aromatic rings. Computational analysis reveals that short-range interactions are dominated by strong dispersion forces, enabling metastable dicationic dimers to form without covalent intermolecular bonding. Surrounding counterions then provide a background source of charge balance, imparting strong thermodynamic stability to the system. Additionally, these counterions form a weak but attractive electrostatic bridge between the monomer units, contributing to the surprisingly short observed intermolecular C3-C3 centroid distance. PMID:26584632

  18. 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.

  19. 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).

  20. Submit and disulfide structure of monomeric and dimeric forms of detergent-soluble HLA antigens.

    PubMed

    Springer, T A; Robb, R J; Terhorst, C; Strominger, J L

    1977-07-10

    The structure of monomeric and disulfide-bonded dimeric forms of HLA antigens has been studied. Detergent-soluble HLA antigen heavy chains contain one or two easily reduced sulfhydryl groups not found in papain-solubilized HLA antigens, as demonstrated by amino acid analysis (Springer, T. A., and Strominger, J.L. (1976) Proc. Natl. Acad. Sci. U.S.A. 73, 2481-2485, and Terhorst, C., Parham, P., Mann, D.L., and Strominger, J.L. (1976) Proc. Natl. Acad. Sci. U.S.A. 73, 910-914) and by labeling with iodo[3H]acetate. Dimer formation occurred during purification, since it was prevented by pretreatment of membranes containing HLA antigen with iodoacetamide. Cross-linking studies showed that the non-disulfide-bonded form of HLA antigens contains one subunit each of the Mr = 44,000 heavy chain and the Mr = 12,000 light chain (beta2-microglobulin). PMID:873911

  1. 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.

  2. 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

  3. Recombinant RXFP1-LDL-A module does not form dimers.

    PubMed

    Petrie, Emma J; Periguini, Matthew A; Bathgate, Ross A D; Gooley, Paul R

    2013-01-01

    The Relaxin receptor, RXFP1, is a complex G-protein coupled receptor (GPCR). It has a rhodopsin-like 7 transmembrane helix region and a large ecto-domain containing Leucine-rich repeats and a Low Desnsity Lipoprotein Class-A module at the N-terminus. RXFP1 and the closely related receptor for INSL3, RXFP2 are the only mammalian GPCRs to contain an LDL-A module. The LDL-A module has been shown to be essential for receptor signal activation. RXFP1, like other GPCRs, has been shown to form dimers however the interface upon association is currently unknown. As LDL-A modules are commonly found as repeats we hypothesized that the LDL-A module may associate at the dimer interface and play a role in receptor activation. To this end we analyzed the ability for the LDL-A module to oligomerise via Analytical Ultracentrifugation (AUC). PMID:24640556

  4. Fluorescent triplex-forming DNA oligonucleotides labeled with a thiazole orange dimer unit

    PubMed Central

    Ikeda, Shuji; Yanagisawa, Hiroyuki; Yuki, Mizue; Okamoto, Akimitsu

    2013-01-01

    Fluorescent probes for the detection of a double-stranded DNA were prepared by labeling a triplex-forming DNA oligonucleotide with a thiazole orange (TO) dimer unit. They belong to ECHO (exciton-controlled hybridization-sensitive fluorescent oligonucleotide) probes which we have previously reported. The excitonic interaction between the two TO molecules was expected to effectively suppress the background fluorescence of the probes. The applicability of the ECHO probes for the detection of double-stranded DNA was confirmed by examining the thermal stability and photophysical and kinetic properties of the DNA triplexes formed by the ECHO probes. PMID:23445822

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

    PubMed Central

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

    2015-01-01

    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. PMID:26013289

  6. 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.

  7. 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. PMID:25176171

  8. 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.

  9. 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

  10. Hepatitis delta virus antigen forms dimers and multimeric complexes in vivo.

    PubMed Central

    Wang, J G; Lemon, S M

    1993-01-01

    Although the hepatitis delta virus genome contains multiple open reading frames, only one of these reading frames is known to be expressed during replication of the virus. This open reading frame encodes two distinct molecular species of hepatitis delta antigen (HDAg), p24 delta and p27 delta, depending on the location of the stop codon which terminates translation. We found antibody specific for p27 delta to be capable of precipitating p24 delta in extracts of infected liver, indicating that p27 delta and p24 delta form heterologous complexes in vivo. After cross-linking with 0.05% glutaraldehyde, specific HDAg dimers were detected in antigen prepared from both the liver and serum of an HDV-infected woodchuck carrier of woodchuck hepatitis virus. Guanidine HCl-denatured HDAg extracted from liver and dialyzed against phosphate-buffered saline sedimented in rate-zonal sucrose density gradients as 15S multimeric complexes. These 15S multimers were stable in the presence of 1.2% Nonidet P-40. After RNase digestion, the 15S complex was reduced to a 12S complex without associated RNA, while boiling for 3 min in 1% sodium dodecyl sulfate-0.5% 2-mercaptoethanol further reduced the 15S complex to 3S HDAg monomers. In the absence of glutaraldehyde cross-linking, HDAg extracted from liver migrated as monomer species in reducing and nonreducing gels, suggesting that the conserved cysteine residue present in p27 delta does not play a role in the formation of either dimers or multimers. On the other hand, an amino-terminal chymotrypsin-digested HDAg fragment, with a predicted length of 81 or less amino acids, retained the ability to form dimers, consistent with the hypothesis that a coiled-coil motif present between residues 27 and 58 may play a role in HDAg protein interactions in vivo. Images PMID:7677957

  11. 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

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

    PubMed

    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

    2016-04-23

    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

  13. Suppressive effects of cacao polyphenols on the development of atherosclerosis in apolipoprotein E-deficient mice.

    PubMed

    Natsume, Midori; Baba, Seigo

    2014-01-01

    Previous studies in humans have shown that the cacao polyphenols, (-)-epicatechin and its oligomers, prevent in vitro and ex vivo low-density lipoprotein oxidation mediated by free radical generators and metal ions and also reduce plasma LDL-cholesterol levels. The aim of this study was to examine the effects of cacao polyphenols on the development of atherosclerosis in apolipoprotein E-deficient (-/-) mice. Mice aged 8 weeks (n = 90) were randomized into three groups, and fed either normal mouse chow (controls) or chow supplemented with 0.25 or 0.40 % cacao polyphenols for 16 weeks. The mean plaque area in cross-sections of the brachiocephalic trunk was measured and found to be lower in the 0.25 % cacao polyphenol group than in the control group (p < 0.05). Pathological observations showed that accumulation of cholesterol crystals in the plaque area was greater in the control group compared with the 0.40 % cacao polyphenol group (p < 0.05). Immunochemical staining in the 0.25 and 0.40 % groups showed that expression of the cell adhesion molecules (VCAM-1 and ICAM-1) and production of oxidative stress markers (4-hydroxynonenal, hexanoyl-lysine, and dityrosine) were reduced in cross-sections of the brachiocephalic trunk. These results suggest that cacao polyphenols inhibit the development of atherosclerosis in apolipoprotein E-deficient (-/-) mice by reducing oxidative stress and inflammatory responses. PMID:24374929

  14. Apolipoprotein E knockout induced inflammatory responses related to microglia in neonatal mice brain via astrocytes

    PubMed Central

    Liu, Yimei; Xu, Xiaohua; Dou, Hongbo; Hua, Ying; Xu, Jinwen; Hui, Xu

    2015-01-01

    More and more evidences suggestted that ApoE plays an important role in modulating the systemic and central nervous inflammatory responses. However, there is a lack of exacted mechanism of ApoE. In this study, we aimed to investigate whether apolipoprotein E (ApoE) induced inflammatory responses and apoptosis in neonatal mice brain from ApoE deficient (ApoE-/-) and wildtype (WT). Compared to control group, the microglia cell from ApoE-/- mice showed more severe inflammation and cell death such as iNOS and IL-1β. Furthermore, anti-inflammatory such as TGF-β, IL-10 from microglia and astrocytes in ApoE-/- mice were decreased. On the other way, TGF-β from astrocytes can inhibit inflammation factors secretion from microglia. Our findings suggested that the anti- inflammation factor such as IL-10 mainly from microglia and TGF-β mainly from astrocyte is significant decreased after Loss of ApoE function in ApoE-/- mice which induced severe inflammation. Furthrtmore, anti- inflammation factor such as IL-10 and TGF-β Therefore, we conclude that apolipoprotein E knockout induced inflammatory responses related to microglia in neonatal mice brain via astrocytes. PMID:25785051

  15. Anti-atherosclerotic effect of simvastatin depends on the presence of apolipoprotein E.

    PubMed

    Wang, Yi Xin; Martin-McNulty, Baby; Huw, Ling Yuh; da Cunha, Valdeci; Post, Joe; Hinchman, Josephine; Vergona, Ronald; Sullivan, Mark E; Dole, William; Kauser, Katalin

    2002-05-01

    Low density lipoprotein receptor deficient (LDLR-KO) and apolipoprotein E deficient (apo E-KO) mice both develop hyperlipidemia and atherosclerosis by different mechanisms. The aim of the present study was to compare the effects of simvastatin on cholesterol levels, endothelial dysfunction, and aortic lesions in these two models of experimental atherosclerosis. Male LDLR-KO mice fed a high cholesterol (HC; 1%) diet developed atherosclerosis at 8 months of age with hypercholesterolemia. The addition of simvastatin (300 mg/kg daily) to the HC diet for 2 more months lowered total cholesterol levels by approximately 57% and reduced aortic plaque area by approximately 15% compared with the LDLR-KO mice continued on HC diet alone, P<0.05. Simvastatin treatment also improved acetylcholine (ACh)-induced endothelium-dependent vasorelaxation in isolated aortic rings, which was associated with an increase in NOS-3 expression by approximately 88% in the aorta measured by real time polymerase chain reaction (PCR), P<0.05. In contrast, in age-matched male apo E-KO mice fed a normal diet, the same treatment of simvastatin elevated serum total cholesterol by approximately 35%, increased aortic plaque area by approximately 15%, and had no effect on endothelial function. These results suggest that the therapeutic effects of simvastatin may depend on the presence of a functional apolipoprotein E. PMID:11947894

  16. Grape powder polyphenols attenuate atherosclerosis development in apolipoprotein E deficient (E0) mice and reduce macrophage atherogenicity.

    PubMed

    Fuhrman, Bianca; Volkova, Nina; Coleman, Raymond; Aviram, Michael

    2005-04-01

    The beneficial health effects of red wine have been attributed to the antioxidant activity of its polyphenols. The present study investigated the effects of a standardized freeze-dried powder made from fresh grapes, rich in grape-specific polyphenols and free of alcohol, on oxidative stress, atherogenicity of macrophages, and the development of atherosclerotic lesions in apolipoprotein E deficient (E(0)) mice. Thirty E(0) mice were assigned to 3 groups. Mice consumed water alone (control), 150 mug total polyphenols/d in the form of grape powder (grape powder), or the equivalent amount of glucose and fructose (placebo) in drinking water for 10 wk. Consumption of grape powder reduced the atherosclerotic lesion area by 41% (P < 0.0002) compared to the control or placebo mice. The antiatherosclerotic effect was at least partly due to a significant 8% reduction in serum oxidative stress, an up to 22% increase in serum antioxidant capacity, a significant 33% reduction in macrophage uptake of oxidized LDL, and a 25% decrease in macrophage-mediated oxidation of LDL relative to controls. Grape powder directly protected both plasma LDL and macrophages from oxidative stress in vitro. We conclude that polyphenols from fresh grape powder directly affect macrophage atherogenicity by reducing macrophage-mediated oxidation of LDL and cellular uptake of oxidized LDL. Both of these processes can eventually reduce macrophage cholesterol accumulation and foam cell formation and hence attenuate atherosclerosis development. PMID:15795424

  17. 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

  18. 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

  19. A 12-week worksite health promotion program reduces cardiovascular risk factors in male workers with the apolipoprotein E2 and apolipoprotein E3 genotypes, but not in apolipoprotein E4 genotype.

    PubMed

    Cho, Sang-Woon; Kang, Ji-Yeon; Park, Yoo-Kyoung; Paek, Yun-Mi; Choi, Tae-In

    2009-08-01

    Worksite health promotion programs focusing on diet and lifestyle modification have been shown to improve health outcomes in workers. The purpose of this study was to investigate whether a 12-week worksite health promotion program shows different response of cardiovascular risk factors in subjects according to apolipoprotein E (Apo E) genotype and obesity level in 141 male Korean industrial workers. We hypothesized that the health changes of a 12-week intervention may not be the same within Apo E genotypes in nonobese and obese subjects. They received 5 face-to-face meetings based on their health profiles. In obese group carrying Apo E3 genotype, body mass index, body fat (%), waist circumference, waist-hip ratio, and systolic blood pressure were decreased, as well as intakes of energy (P = .000) and carbohydrate (P = .005). High-density lipoprotein cholesterol (P = .004) level was improved in individuals with the Apo E2 genotype. These beneficial effects were only observed in individuals with the Apo E2 or Apo E3 genotype. Multiple linear regression revealed that obesity was strongly correlated with waist circumference (P = .002), plasma total cholesterol (P = .037), and changes in dietary cholesterol intake (P = .011) in individuals with the Apo E3 genotype, whereas only changes in dietary fat intake (P = .044) was correlated in those with the Apo E4 genotype. Overall, the results of this study suggest that a health promotion program can be a useful method of improving cardiovascular risk factors and dietary intake in industrial workers with certain genotypes only. Therefore, further research is needed to develop a tailored, long-term worksite health promotion program based on genetic background. PMID:19761888

  20. 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.

  1. 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

  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. 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

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

    PubMed Central

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

    2014-01-01

    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-RanGTP 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. DOI: http://dx.doi.org/10.7554/eLife.04121.001 PMID:25486595

  5. Helix packing and orientation in the transmembrane dimer of gp55-P of the spleen focus forming virus.

    PubMed

    Liu, Wei; Crocker, Evan; Constantinescu, Stefan N; Smith, Steven O

    2005-08-01

    gp55-P is a dimeric membrane protein with a single transmembrane helix that is coded by the env gene of the polycythemic strain of the spleen focus forming virus. gp55-P activates the erythropoietin (Epo) receptor through specific transmembrane helix interactions, leading to Epo-independent growth of erythroid progenitors and eventually promoting erythroleukemia. We describe the use of magic angle spinning deuterium NMR to establish the structure of the transmembrane dimer of gp55-P in model membranes. Comparison of the deuterium lineshapes of leucines in the center (Leu(396-399)) and at the ends (Leu(385), Leu(407)) of the transmembrane sequence shows that gp55-P has a right-handed crossing angle with Leu(399) packed in the dimer interface. We discuss the implications of the structure of the gp55-P transmembrane dimer for activation of the Epo receptor. PMID:15894629

  6. Overcoming the signaling defect of Lyn-sequestering, signal-curtailing FcepsilonRI dimers: aggregated dimers can dissociate from Lyn and form signaling complexes with Syk.

    PubMed

    Lara, M; Ortega, E; Pecht, I; Pfeiffer, J R; Martinez, A M; Lee, R J; Surviladze, Z; Wilson, B S; Oliver, J M

    2001-10-15

    Clustering the tetrameric (alphabetagamma(2)) IgE receptor, FcepsilonRI, on basophils and mast cells activates the Src-family tyrosine kinase, Lyn, which phosphorylates FcepsilonRI beta and gamma subunit tyrosines, creating binding sites for the recruitment and activation of Syk. We reported previously that FcepsilonRI dimers formed by a particular anti-FcepsilonRI alpha mAb (H10) initiate signaling through Lyn activation and FcepsilonRI subunit phosphorylation, but cause only modest activation of Syk and little Ca(2+) mobilization and secretion. Curtailed signaling was linked to the formation of unusual, detergent-resistant complexes between Lyn and phosphorylated receptor subunits. Here, we show that H10-FcepsilonRI multimers, induced by adding F(ab')(2) of goat anti-mouse IgG to H10-treated cells, support strong Ca(2+) mobilization and secretion. Accompanying the recovery of signaling, H10-FcepsilonRI multimers do not form stable complexes with Lyn and do support the phosphorylation of Syk and phospholipase Cgamma2. Immunogold electron microscopy showed that H10-FcepsilonRI dimers colocalize preferentially with Lyn and are rarely within the osmiophilic "signaling domains" that accumulate FcepsilonRI and Syk in Ag-treated cells. In contrast, H10-FcepsilonRI multimers frequently colocalize with Syk within osmiophilic patches. In sucrose gradient centrifugation analyses of detergent-extracted cells, H10-treated cells show a more complete redistribution of FcepsilonRI beta from heavy (detergent-soluble) to light (Lyn-enriched, detergent-resistant) fractions than cells activated with FcepsilonRI multimers. We hypothesize that restraints imposed by the particular orientation of H10-FcepsilonRI dimers traps them in signal-initiating Lyn microdomains, and that converting the dimers to multimers permits receptors to dissociate from Lyn and redistribute to separate membrane domains that support Syk-dependent signal propagation. PMID:11591756

  7. 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. PMID:26921119

  8. Apolipoprotein E and Sex Bias in Cerebrovascular Aging of Men and Mice.

    PubMed

    Finch, Caleb E; Shams, Sara

    2016-09-01

    Alzheimer disease (AD) research has mainly focused on neurodegenerative processes associated with the classic neuropathologic markers of senile plaques and neurofibrillary tangles. Additionally, cerebrovascular contributions to dementia are increasingly recognized, particularly from cerebral small vessel disease (SVD). Remarkably, in AD brains, the apolipoprotein E (ApoE) ɛ4 allele shows male excess for cerebral microbleeds (CMBs), a marker of SVD, which is opposite to the female excess of plaques and tangles. Mouse transgenic models add further complexities to sex-ApoE ɛ4 allele interactions, with female excess of both CMBs and brain amyloid. We conclude that brain aging and AD pathogenesis cannot be understood in humans without addressing major gaps in the extent of sex differences in cerebrovascular pathology. PMID:27546867

  9. Confirmation of association between the e4 allele of apolipoprotein E and Alzheimer's disease.

    PubMed Central

    Liddell, M; Williams, J; Bayer, A; Kaiser, F; Owen, M

    1994-01-01

    The Apo E genotype of 86 patients with Alzheimer's disease (AD) and 77 age matched controls was determined by digestion of Apo E PCR products with the restriction enzyme CfoI. The frequency of the e4 allele was significantly increased in the patient group (0.33) as compared with controls (0.12). This effect was seen in patients with a family history and in sporadic cases. The odds ratio in homozygotes for the e4 allele was 11.24 (95% confidence interval 2.45-51.50). There was no relationship between age of onset and Apo E genotype. There was no linkage disequilibrium between the apolipoprotein E locus and a TaqI polymorphism at the Apo CII locus, and no allelic association between Apo CII and AD. Images PMID:8014966

  10. Neuropathology and apolipoprotein E profile of aged chimpanzees: implications for Alzheimer disease.

    PubMed Central

    Gearing, M; Rebeck, G W; Hyman, B T; Tigges, J; Mirra, S S

    1994-01-01

    Neuropathological findings in three aged chimpanzees were compared with those in rhesus monkeys and individuals with Alzheimer disease. Senile plaques and blood vessels were immunoreactive for amyloid beta-protein and apolipoprotein E (apoE) in the nonhuman primates, recapitulating findings in human aging and Alzheimer disease. Neurofibrillary tangles, another hallmark of Alzheimer disease, were absent. PCR/restriction-enzyme analysis in chimpanzees revealed an APOE profile similar to the human APOE type 4 allele associated with an increased risk of Alzheimer disease. These findings militate against the hypothesis that the absence of APOE type 3 allele predisposes to neurofibrillary tangle formation and support the value of aged primates for exploring mechanisms of amyloid processing and the role of apoE. Images PMID:7937774

  11. 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. PMID:9672379

  12. Sex, but not Apolipoprotein E Polymorphism, Differences in Spatial Performance in Young Adults.

    PubMed

    Yasen, Alia L; Raber, Jacob; Miller, Jeremy K; Piper, Brian J

    2015-11-01

    The purpose of this study was to examine how sex and apolipoprotein E (APOE) genotype contribute to individual differences in spatial learning and memory. The associations of APOE genotype with neurocognitive function have been well studied among the elderly but less is known at earlier ages. Young adults (n = 169, 88 females) completed three neurocognitive tasks: mental rotation, spatial span, and Memory Island, a spatial navigation test. Males outperformed females on all three tasks: finding the hidden targets more quickly on Memory Island (Cohen's d = 0.62) and obtaining higher scores on mental rotation (d = 0.54) and spatial span (d = 0.37). In contrast, no significant effects of APOE were observed. The identified sex differences elaborate upon past literature documenting sexually dimorphic performance on specific neurobehavioral tasks. PMID:25750133

  13. 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.

  14. Metabolism of lipoproteins containing apolipoprotein B-100 in blood plasma of rabbits: heterogeneity related to the presence of apolipoprotein E.

    PubMed Central

    Yamada, N; Shames, D M; Stoudemire, J B; Havel, R J

    1986-01-01

    Apolipoprotein B-100 is a constant component of very low density lipoproteins (VLDL), intermediate density lipoproteins (IDL), and low density lipoproteins (LDL) in mammalian blood plasma. We have found that each of these classes of lipoproteins includes particles that contain apolipoprotein E (B,E particles) as well as particles that lack this protein (B particles). These two species can be separated by immunosorption on columns of anti-apolipoprotein E bound to Sepharose. We have injected radioiodinated VLDL, IDL, and LDL intravenously into recipient rabbits and have determined the concentration of radioiodine in apolipoprotein B-100 in B,E and B particles in whole-blood plasma obtained at intervals for 24 hr. We have developed a multicompartmental model that is consistent with this new information and with current concepts of lipoprotein metabolism. The model indicates that all apolipoprotein B-100 enters the blood as VLDL, of which about 90% is in B,E particles. Most VLDL B,E particles are removed rapidly from the blood, and only a small fraction is converted to IDL and eventually to LDL (overall conversion is approximately 2%). By contrast, a much smaller fraction of VLDL B particles is removed directly, and approximately 27% is converted to LDL. In addition, some B,E particles are converted to B particles as VLDL are converted to LDL, so that most LDL particles lack apolipoprotein E. Fractional rates of irreversible removal of B,E and B particles in IDL and LDL are similar. Our results indicate that the presence of apolipoprotein E is a major determinant of the metabolic fate of VLDL particles and support the hypothesis that polyvalent binding of particles containing several molecules of apolipoprotein E promotes receptor-dependent endocytosis of hepatogenous lipoproteins and limits their conversion to lipoproteins of higher density. PMID:3458191

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

    PubMed Central

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

    2016-01-01

    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. PMID:27072897

  16. 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.

  17. 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

    2016-01-01

    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. PMID:27072897

  18. High frequency of the apolipoprotein E *4 allele in African pygmies and most of the African populations in sub-Saharan Africa.

    PubMed

    Zekraoui, L; Lagarde, J P; Raisonnier, A; Gérard, N; Aouizérate, A; Lucotte, G

    1997-08-01

    Apolipoprotein E genotypes (alleles *2, *3, and *4) have been determined in 70 Aka Pygmies and 470 unrelated African sub-Saharan subjects. Allele frequencies for Pygmies are 5.7% for APOE*2, 53.6% for APOE*3, and 40.7% for APOE*4, and the global proportions for sub-Saharan subjects are 11.6% for APOE*2, 70.6% for APOE*3, and 17.8% for APOE*4. The frequencies in some ethnic groups are statistically different from the overall mean in the Afar and the Isa, the Ewe (Togo), the Malinke (Guinea), and the Mossi; three ethnic groups have a higher allele frequency of APOE*4 (Fon, 29.4%; Zairians, 33.3%; Tutsi, 38.5%). The APOE*4 allele is considered the ancestral form because of its high frequency in African Pygmies and other aboriginal populations. PMID:9198315

  19. Dysferlin Forms a Dimer Mediated by the C2 Domains and the Transmembrane Domain In Vitro and in Living Cells

    PubMed Central

    Xu, Li; Pallikkuth, Sandeep; Hou, Zhanjia; Mignery, Gregory A.; Robia, Seth L.; Han, Renzhi

    2011-01-01

    Dysferlin was previously identified as a key player in muscle membrane repair and its deficiency leads to the development of muscular dystrophy and cardiomyopathy. However, little is known about the oligomerization of this protein in the plasma membrane. Here we report for the first time that dysferlin forms a dimer in vitro and in living adult skeletal muscle fibers isolated from mice. Endogenous dysferlin from rabbit skeletal muscle exists primarily as a ∼460 kDa species in detergent-solubilized muscle homogenate, as shown by sucrose gradient fractionation, gel filtration and cross-linking assays. Fluorescent protein (YFP) labeled human dysferlin forms a dimer in vitro, as demonstrated by fluorescence correlation spectroscopy (FCS) and photon counting histogram (PCH) analyses. Dysferlin also dimerizes in living cells, as probed by fluorescence resonance energy transfer (FRET). Domain mapping FRET experiments showed that dysferlin dimerization is mediated by its transmembrane domain and by multiple C2 domains. However, C2A did not significantly contribute to dimerization; notably, this is the only C2 domain in dysferlin known to engage in a Ca-dependent interaction with cell membranes. Taken together, the data suggest that Ca-insensitive C2 domains mediate high affinity self-association of dysferlin in a parallel homodimer, leaving the Ca-sensitive C2A domain free to interact with membranes. PMID:22110769

  20. Evidence for major gene inheritance of Alzheimer disease in families of patients with and without apolipoprotein E epsilon 4.

    PubMed Central

    Rao, V. S.; Cupples, A.; van Duijn, C. M.; Kurz, A.; Green, R. C.; Chui, H.; Duara, R.; Auerbach, S. A.; Volicer, L.; Wells, J.; van Broeckhoven, C.; Growdon, J. H.; Haines, J. L.; Farrer, L. A.

    1996-01-01

    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 epsilon 4, 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. PMID:8751868

  1. 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.

  2. 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.

  3. Plant gamma-tubulin interacts with alphabeta-tubulin dimers and forms membrane-associated complexes.

    PubMed

    Dryková, Denisa; Cenklová, Vēra; Sulimenko, Vadym; Volc, Jindrich; Dráber, Pavel; Binarová, Pavla

    2003-02-01

    gamma-Tubulin is assumed to participate in microtubule nucleation in acentrosomal plant cells, but the underlying molecular mechanisms are still unknown. Here, we show that gamma-tubulin is present in protein complexes of various sizes and different subcellular locations in Arabidopsis and fava bean. Immunoprecipitation experiments revealed an association of gamma-tubulin with alphabeta-tubulin dimers. gamma-Tubulin cosedimented with microtubules polymerized in vitro and localized along their whole length. Large gamma-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 gamma-tubulin complexes were active in microtubule nucleation, but nucleation activity was not observed for the smaller complexes. Punctate gamma-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 gamma-tubulin complexes with dynamic membranes might ensure the flexibility of noncentrosomal microtubule nucleation. Moreover, the presence of other molecular forms of gamma-tubulin suggests additional roles for this protein species in microtubule organization. PMID:12566585

  4. Trapping of bulky guests inside dimeric molecular capsules formed by a deep-cavity cavitand.

    PubMed

    Qiu, Yanhua; Yi, Song; Kaifer, Angel E

    2012-05-18

    The inclusion of three bulky guests, adamantyl(ferrocenylmethyl)amine (2), adamantylferrocenecarboxylamide (3), and 1,1'-bis(adamantylaminomethyl)ferrocene (4), inside dimeric molecular capsules formed by an octaacid deep-cavity cavitand (1) was investigated using (1)H NMR spectroscopy and voltammetric techniques. Guests 2 and 3 were encapsulated inside 1(2) assemblies, as evidenced by (1)H NMR spectroscopic data. Although both guests are electroactive, the supramolecular complexes 2@1(2) and 3@1(2) showed no voltammetric current responses in the potential window corresponding to the electrochemical oxidation of their ferrocenyl groups. In contrast, each of the adamantyl ends of compound 4 is bound by the cavitand 1, but the central ferrocene residue was not fully encapsulated in this supramolecular assembly and the voltammetric behavior of 4·1(2) was clearly detected. In marked contrast with the experimental results obtained with guests 2 and 3, we could not obtain any evidence for the simultaneous encapsulation of free ferrocene and adamantane inside the 1(2) capsular assembly. PMID:22524404

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

    PubMed

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

    2016-07-14

    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:27419397

  7. Associative recognition in mild cognitive impairment: relationship to hippocampal volume and apolipoprotein E.

    PubMed

    Troyer, Angela K; Murphy, Kelly J; Anderson, Nicole D; Craik, Fergus I M; Moscovitch, Morris; Maione, Andrea; Gao, Fuqiang

    2012-12-01

    Associative memory involves remembering relations between items of information and is critically dependent on the hippocampus, a brain structure that shows early changes in amnestic mild cognitive impairment (aMCI) and Alzheimer's disease. We examined associative and item memory in aMCI with a focus on the role of medial-temporal lobe regions and genetic risk for Alzheimer's disease. Twenty-four individuals with aMCI and 21 demographically matched healthy older adults underwent associative recognition testing, structural brain imaging, and apolipoprotein E (ApoE) genotyping. A significant interaction between group and recognition type indicated poorer associative recognition than item recognition across tasks in the aMCI group relative to controls. Within the aMCI group, associative but not item recognition showed sizable and significant correlations with hippocampal volume (but not with other medial temporal-lobe structures) and with number of ApoE ε4 alleles. Correlations were smaller and generally not significant in the control group. Our findings replicate and extend previous studies by showing an associative recognition impairment in aMCI that is not accounted for by an item recognition deficit, is related to structural integrity of the hippocampus, and increases with genetic risk for Alzheimer's disease. PMID:23103838

  8. Correlations between apolipoprotein E ε4 gene dose and brain-imaging measurements of regional hypometabolism

    PubMed Central

    Reiman, Eric M.; Chen, Kewei; Alexander, Gene E.; Caselli, Richard J.; Bandy, Daniel; Osborne, David; Saunders, Ann M.; Hardy, John

    2005-01-01

    Patients with Alzheimer's disease (AD) have abnormally low positron emission tomography (PET) measurements of the cerebral metabolic rate for glucose (CMRgl) in regions of the precuneus and the posterior cingulate, parietotemporal, and frontal cortex. Apolipoprotein E (APOE) ε4 gene dose (i.e., the number of ε4 alleles in a person's APOE genotype) is associated with a higher risk of AD and a younger age at dementia onset. We previously found that cognitively normal late-middle-aged APOE ε4 carriers have abnormally low CMRgl in the same brain regions as patients with probable Alzheimer's dementia. In a PET study of 160 cognitively normal subjects 47–68 years of age, including 36 ε4 homozygotes, 46 heterozygotes, and 78 ε4 noncarriers who were individually matched for their gender, age, and educational level, we now find that ε4 gene dose is correlated with lower CMRgl in each of these brain regions. This study raises the possibility of using PET as a quantitative presymptomatic endophenotype to help evaluate the individual and aggregate effects of putative genetic and nongenetic modifiers of AD risk. PMID:15932949

  9. An ultrasensitive electrochemical immunosensor for apolipoprotein E4 based on fractal nanostructures and enzyme amplification.

    PubMed

    Liu, Yibiao; Xu, Li-Ping; Wang, Shuqi; Yang, Weizhao; Wen, Yongqiang; Zhang, Xueji

    2015-09-15

    Human apolipoprotein E4 (APOE4) is a major risk factor for Alzheimer's disease (AD) and can greatly increase the morbidity. In this work, an ultrasensitive sandwich-type electrochemical immunosensor for the quantitative detection of APOE4 was designed based on fractal gold (FracAu) nanostructures and enzyme amplification. The FracAu nanostructures were directly electrodeposited by hydrogen tetrachloroaurate (HAuCl4) on polyelectrolytes modified indium tin oxide (ITO) electrode. The sensing performances of the modified interface were investigated by cyclic voltammetry (CV). After functionalization with HRP-labeled APOE4 antibody, the human APOE4 could be detected quantitatively by current response. The current response has a linear relationship with the logarithm of human APOE4 concentrations in a range from 1.0 to 10,000.0 ng/mL, with a detection limit of 0.3 ng/mL. The fabricated APOE4 electrochemical immunosensor exhibits strong specificity, high sensitivity, low detection limit and wide linear range. The detection of human APOE4 provides a strong support for the prevention of AD and early-stage warning for those susceptible populations. PMID:25950934

  10. A1 adenosine receptor deficiency or inhibition reduces atherosclerotic lesions in apolipoprotein E deficient mice

    PubMed Central

    Teng, Bunyen; Smith, Jonathan D.; Rosenfeld, Michael E.; Robinet, Peggy; Davis, Mary E.; Morrison, R. Ray; Mustafa, S. Jamal

    2014-01-01

    Aims The goal of this study was to determine whether the A1 adenosine receptor (AR) plays a role in atherosclerosis development and to explore its potential mechanisms. Methods and results Double knockout (DKO) mice, deficient in the genes encoding A1 AR and apolipoprotein E (apoE), demonstrated reduced atherosclerotic lesions in aortic arch (en face), aortic root, and innominate arteries when compared with apoE-deficient mice (APOE-KO) of the same age. Treating APOE-KO with an A1 AR antagonist (DPCPX) also led to a concentration-dependent reduction in lesions. The total plasma cholesterol and triglyceride levels were not different between DKO and APOE-KO; however, higher triglyceride was observed in DKO fed a high-fat diet. DKO also had higher body weights than APOE-KO. Plasma cytokine concentrations (IL-5, IL-6, and IL-13) were significantly lower in DKO. Proliferating cell nuclear antigen expression was also significantly reduced in the aorta from DKO. Despite smaller lesions in DKO, the composition of the innominate artery lesion and cholesterol loading and efflux from bone marrow-derived macrophages of DKO were not different from APOE-KO. Conclusion The A1 AR may play a role in the development of atherosclerosis, possibly due to its pro-inflammatory and mitogenic properties. PMID:24525840

  11. CLI-095 decreases atherosclerosis by modulating foam cell formation in apolipoprotein E-deficient mice

    PubMed Central

    WANG, XIAO-QING; WAN, HUI-QING; WEI, XIAN-JING; ZHANG, YING; QU, PENG

    2016-01-01

    Toll-like receptor 4 (TLR4) is considered to have a critical role in the occurrence and development of atherosclerosis in atherosclerosis-prone mice; however, it remains uncertain whether treatment with a TLR4 inhibitor may attenuate atherosclerosis. The present study aimed to determine the vascular protective effects of the TLR4 inhibitor CLI-095 on apolipoprotein E-deficient (ApoE−/−) mice. ApoE−/− mice were fed either chow or a high-fat diet, and were treated with or without CLI-095 for 10 weeks. The mean atherosclerotic plaque area in the aortic sections of CLI-095-treated mice was 54.3% smaller than in the vehicle-treated mice (P=0.0051). In vitro, murine peritoneal macrophages were treated with or without CLI-095, and were subsequently stimulated with oxidized low-density lipoprotein. Treatment with CLI-095 markedly reduced the expression levels of lectin-like oxidized low-density lipoprotein receptor-1 and acyl-coenzyme A:cholesterol acyltransferase-1, and significantly upregulated the expression levels of ATP-binding cassette transporter A1, predominantly via suppressing activation of the TLR4/nuclear factor-κB signaling pathway. The results of the present study indicated that the TLR4 inhibitor CLI-095 has the ability to suppress the progression of atherosclerosis in an in vivo model by reducing macrophage foam cell formation. PMID:27176130

  12. 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.

  13. Opposite roles of apolipoprotein E in normal brains and in Alzheimer’s disease

    PubMed Central

    Russo, Claudio; Angelini, Giovanna; Dapino, Debora; Piccini, Alessandra; Piombo, Giuseppe; Schettini, Gennaro; Chen, Shu; Teller, Jan K.; Zaccheo, Damiano; Gambetti, Pierluigi; Tabaton, Massimo

    1998-01-01

    We have characterized the interaction between apolipoprotein E (apoE) and amyloid β peptide (Aβ) in the soluble fraction of the cerebral cortex of Alzheimer’s disease (AD) and control subjects. Western blot analysis with specific antibodies identified in both groups a complex composed of the full-length apoE and Aβ peptides ending at residues 40 and 42. The apoE–Aβ soluble aggregate is less stable in AD brains than in controls, when treated with the anionic detergent SDS. The complex is present in significantly higher quantity in control than in AD brains, whereas in the insoluble fraction an inverse correlation has previously been reported. Moreover, in the AD subjects the Aβ bound to apoE is more sensitive to protease digestion than is the unbound Aβ. Taken together, our results indicate that in normal brains apoE efficiently binds and sequesters Aβ, preventing its aggregation. In AD, the impaired apoE–Aβ binding leads to the critical accumulation of Aβ, facilitating plaque formation. PMID:9861015

  14. Opposite roles of apolipoprotein E in normal brains and in Alzheimer's disease.

    PubMed

    Russo, C; Angelini, G; Dapino, D; Piccini, A; Piombo, G; Schettini, G; Chen, S; Teller, J K; Zaccheo, D; Gambetti, P; Tabaton, M

    1998-12-22

    We have characterized the interaction between apolipoprotein E (apoE) and amyloid beta peptide (Abeta) in the soluble fraction of the cerebral cortex of Alzheimer's disease (AD) and control subjects. Western blot analysis with specific antibodies identified in both groups a complex composed of the full-length apoE and Abeta peptides ending at residues 40 and 42. The apoE-Abeta soluble aggregate is less stable in AD brains than in controls, when treated with the anionic detergent SDS. The complex is present in significantly higher quantity in control than in AD brains, whereas in the insoluble fraction an inverse correlation has previously been reported. Moreover, in the AD subjects the Abeta bound to apoE is more sensitive to protease digestion than is the unbound Abeta. Taken together, our results indicate that in normal brains apoE efficiently binds and sequesters Abeta, preventing its aggregation. In AD, the impaired apoE-Abeta binding leads to the critical accumulation of Abeta, facilitating plaque formation. PMID:9861015

  15. Granzyme B degrades extracellular matrix and contributes to delayed wound closure in apolipoprotein E knockout mice

    PubMed Central

    Hiebert, P R; Wu, D; Granville, D J

    2013-01-01

    Chronic inflammation and excessive protease activity have a major role in the persistence of non-healing wounds. Granzyme B (GzmB) is a serine protease expressed during chronic inflammation that, in conjunction with perforin, has a well-established role in initiating apoptotic cell death. GzmB is also capable of acting extracellularly, independent of perforin and can degrade several extracellular matrix (ECM) proteins that are critical during wound healing. We used apolipoprotein E (ApoE) knockout (AKO) mice as a novel model of chronic inflammation and impaired wound healing to investigate the role of GzmB in chronic wounds. Wild-type and AKO mice were grown to 7 weeks (young) or 37 weeks (old) of age on a regular chow or high-fat diet (HFD), given a 1-cm diameter full thickness wound on their mid dorsum and allowed to heal for 16 days. Old AKO mice fed a HFD exhibited reduced wound closure, delayed contraction, chronic inflammation and altered ECM remodeling. Conversely, GzmB/ApoE double knockout mice displayed improved wound closure and contraction rates. In addition, murine GzmB was found to degrade both fibronectin and vitronectin derived from healthy mouse granulation tissue. In addition, GzmB-mediated degradation of fibronectin generated a fragment similar in size to that observed in non-healing mouse wounds. These results provide the first direct evidence that GzmB contributes to chronic wound healing in part through degradation of ECM. PMID:23912712

  16. 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. PMID:24675880

  17. The effect of hormone therapy on olfactory sensitivity is dependent on apolipoprotein E genotype.

    PubMed

    Sundermann, Erin E; Gilbert, Paul E; Murphy, Claire

    2008-09-01

    Patients with Alzheimer's disease (AD) show a deficit in olfactory threshold sensitivity. The Apolipoprotein E (ApoE) epsilon4 allele is associated with increased risk of AD and earlier symptom onset. Hormone therapy (HT) may exert neuroprotective effects on brain areas affected by AD. The current study investigated the effect of HT on performance on an olfactory threshold test in epsilon4 positive and epsilon4 negative non-hysterectomized, non-demented, elderly females and AD patients. Among the non-demented participants, epsilon4 positive females who had received HT performed 1) significantly better than those without HT, and 2) at levels similar to those of epsilon4 negative females. In contrast, those without HT who were epsilon4 positive performed significantly worse than those who were epsilon4 negative. HT had no effect on performance in AD patients regardless of epsilon4 status. These results suggest that HT may offer protection against loss of olfactory function in epsilon4 positive individuals in preclinical stages of AD. Future research is warranted in order to investigate further the neuroprotective role of HT on sensory and cognitive functions in non-demented aging individuals. PMID:18620351

  18. Apolipoprotein E may be a critical factor in hormone therapy neuroprotection.

    PubMed

    Struble, Robert G; Cady, Craig; Nathan, Britto P; McAsey, Mary

    2008-01-01

    In this review we examine the evidence for ovarian hormone neuroprotection in chronic neurological diseases, including stroke. We propose that neuroprotection may involve the ability of estrogens to modulate apolipoprotein E (apoE) and its receptor, the low density lipoprotein receptor related protein (LRP). Results from numerous studies have demonstrated that (1) nerve regeneration is severely delayed in apoE-gene knockout (KO) mice as compared to wild-type (WT) littermates; (2) 17beta estradiol replacement in ovariectomized mice resulted in a significant increase in levels of apoE and LRP, in the olfactory bulb (OB) and other brain areas; (3) estradiol treatment increased both apoE and neurite outgrowth in cortical and olfactory neuronal cultures; and (4) estradiol treatment had no effect on neurite outgrowth in cultures deprived of apoE or in the presence of apoE4. In essence these studies suggest that apoE is a critical intermediary for the beneficial effects of 17beta estradiol on nerve repair, which can lead to functional reorganization (plasticity). Future studies of HT should evaluate the effects of apoE genotype and production estradiol on neuroprotection. PMID:18508594

  19. 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. PMID:16534141

  20. Nerve injury stimulates the secretion of apolipoprotein E by nonneuronal cells

    SciTech Connect

    Snipes, G.J.; McGuire, C.B.; Norden, J.J.; Freeman, J.A.

    1986-02-01

    Nerve trauma initiates significant changes in the composition of proteins secreted by nonneuronal cells. The most prominent of these proteins is a 37-kDa protein, whose expression correlates with the time course of nerve development, degeneration, and regeneration. The authors report that the 37-kDa protein is apolipoprotein E (apoE). They produced a specific antiserum against the 37-kDa protein isolated from previously crushed nerves. This antiserum recognizes a 36-kDa protein in rat serum that they have purified and identified as apoE. The anti-37-kDa antiserum also recognizes apoE on electrophoretic transfer blots of authentic samples of high and very low density lipoproteins. The nerve 37-kDa protein comigrates with apoE by two-dimensional electrophoresis, shares a similar amino acid composition, and reacts with an antiserum against authentic apoE. The purified apoE specifically blocks the immunoprecipitation of (TVS)methionine-labeled 37-kDa protein synthesized by nonneuronal cells. Thus, on the basis of its molecular mass, isoelectric point, amino acid composition, and immunological properties, they conclude that the 37-kDa protein is apoE. They also used light microscopic immunochemistry to localize apoE following nerve injury. They propose that apoE is synthesized by phagocytic cells in response to nerve injury for the purpose of mobilizing lipids produced as a consequence of axon degeneration.

  1. 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

  2. Molecular cloning and characterization of the promoter region of the porcine apolipoprotein E gene.

    PubMed

    Xia, Jihan; Hu, Bingjun; Mu, Yulian; Xin, Leilei; Yang, Shulin; Li, Kui

    2014-05-01

    Apolipoprotein E (APOE), a component of lipoproteins plays an important role in the transport and metabolism of cholesterol, and is associated with hyperlipoproteinemia and Alzheimer's disease. In order to further understand the characterization of APOE gene, the promoter of APOE gene of Landrace pigs was analyzed in the present study. The genomic structure and amino acid sequence in pigs were analyzed and found to share high similarity in those of human but low similarity in promoter region. Real-time PCR revealed the APOE gene expression pattern of pigs in diverse tissues. The highest expression level was observed in liver, relatively low expression in other tissues, especially in stomach and muscle. Furthermore, the promoter expressing in Hepa 1-6 was significantly better at driving luciferase expression compared with C2C12 cell. After analysis of porcine APOE gene promoter regions, potential transcription factor binding sites were predicted and two GC signals, a TATA box were indicated. Results of promoter activity analysis indicated that one of potential regulatory elements was located in the region -669 to -259, which was essential for a high expression of the APOE gene. Promoter mutation and deletion analysis further suggested that the C/EBPA binding site within the APOE promoter was responsible for the regulation of APOE transcription. Electrophoretic mobility shift assays also showed the binding site of the transcription factor C/EBPA. This study advances our knowledge of the promoter of the porcine APOE gene. PMID:24464129

  3. Phospholipid liposomes acquire apolipoprotein E in atherogenic plasma and block cholesterol loading of cultured macrophages.

    PubMed Central

    Williams, K J; Tall, A R; Bisgaier, C; Brocia, R

    1987-01-01

    A single infusion of phospholipid liposomes promptly and persistently abolished the ability of hypercholesterolemic rabbit plasma to cause cholesteryl ester loading in cultured macrophages. This phospholipid enrichment of plasma caused moderate stimulation of cellular cholesterol efflux and, unexpectedly, almost complete inhibition of cellular uptake of beta-very low density lipoprotein (beta-VLDL), the major cholesteryl ester-rich particle in hypercholesterolemic rabbit plasma. Cell viability and LDL receptor activity were unaffected. Incubation of liposomes with beta-VLDL resulted in transfer of apolipoprotein-E (apoE) to the liposomes; reisolated apoE-phospholipid liposomes then competed efficiently for cellular apoprotein receptors. Thus, a major mechanism by which phospholipid infusions result in diminished accumulation of cholesteryl ester in cultured macrophages is by blocking cellular uptake of beta-VLDL. The liposomes deplete beta-VLDL of apoE, then compete for receptor-mediated uptake. These results suggest a novel mechanism contributing to the known antiatherogenic effect of phospholipid infusions: infused liposomes acquire apoE, then block uptake of atherogenic lipoproteins by arterial wall macrophages. Images PMID:3571495

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

    PubMed

    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

  5. Effect of dalteparin on atherosclerotic lesion formation in apolipoprotein E-deficient mice.

    PubMed

    Su, Lin; Zhang, Qingwen; Bao, Hui; Li, Wei; Miao, Yide; Yan, Zheng; Chen, Dingbao

    2015-04-01

    We aimed to investigate whether prolonged treatment with dalteparin could inhibit plaque progression. With C57BL/6J mice as the control, genetically deficient apolipoprotein E (apo E) male mice of C57BL/6J strain (apo E(-/-)) were randomly divided into 3 groups. The model group received no dalteparin, while the other 2 groups received dalteparin at 100 and 200 U/kg d, respectively. The aorta was harvested for hematoxylin and eosin staining to observe plaque formation and for immunohistochemical staining to detect the expression of oxidized low-density lipoprotein receptor 1 (LOX-1). The expression of LOX-1 messenger RNA was detected by reverse transcription polymerase chain reaction, while the expression of LOX-1 protein was detected by Western blotting. Dalteparin decreased aortic plaque volume and inhibited aortic LOX-1 protein expression in apo E(-/-) mice. The effect persisted 4 weeks after dalteparin treatment was discontinued. Dalteparin may inhibit atherosclerotic lesions by downregulating the expression of LOX-1 protein. PMID:23965336

  6. Apolipoprotein E on Hepatitis C Virion Facilitates Infection through Interaction with Low Density Lipoprotein Receptor

    PubMed Central

    Owen, David M.; Huang, Hua; Ye, Jin; Gale, Michael

    2009-01-01

    Hepatitis C virus (HCV) infection is a major cause of liver disease. HCV associates with host apolipoproteins and enters hepatocytes through complex processes involving some combination of CD81, claudin-I, occludin, and scavenger receptor BI. Here we show that infectious HCV resembles very low density lipoprotein (VLDL) and that entry involves co-receptor function of the low density lipoprotein receptor (LDL-R). Blocking experiments demonstrate that β-VLDL itself or anti-apolipoprotein E (apoE) antibody can block HCV entry. Knockdown of the LDL-R by treatment with 25-hydroxycholesterol or siRNA ablated ligand uptake and reduced HCV infection of cells, whereas infection was rescued upon cell ectopic LDL-R expression. Analyses of gradient-fractionated HCV demonstrate that apoE is associated with HCV virions exhibiting peak infectivity and dependence upon the LDL-R for cell entry. Our results define the LDL-R as a cooperative HCV co-receptor that supports viral entry and infectivity through interaction with apoE ligand present in an infectious HCV/lipoprotein complex comprising the virion. Disruption of HCV/LDL-R interactions by altering lipoprotein metabolism may therefore represent a focus for future therapy. PMID:19751943

  7. 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.

  8. 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.

  9. Deletion of sirtuin 6 accelerates endothelial dysfunction and atherosclerosis in apolipoprotein E-deficient mice.

    PubMed

    Liu, Zhiping; Wang, Jiaojiao; Huang, Xiaoyang; Li, Zhuoming; Liu, Peiqing

    2016-06-01

    Sirtuin 6 (SIRT6) is a chromatin-associated deacetylase that plays a leading role in genomic stability and aging. However, the precise role of SIRT6 in atherosclerosis, an aging-associated cardiovascular disease, remains elusive. This study aims at defining the role of SIRT6 in atherosclerotic lesion development. SIRT6 messenger RNA and protein expression are markedly decreased in atherosclerotic aortas of apolipoprotein E-deficient (ApoE(-/-)) mice fed a high-cholesterol diet. SIRT6 was knocked down in ApoE(-/-) mice using small hairpin RNAs (shRNAs) lentivirus injection. SIRT6-shRNA-treated ApoE(-/-) mice showed impaired endothelium-dependent vasodilation, increased plaque size (in aortic sinus, aortic root and en face aorta), and augmented plaque vulnerability (evidenced by increased necrotic core areas and macrophage accumulation and reduced collagen content). At the cellular level, SIRT6 depletion by RNA interference in human umbilical vein endothelial cells significantly increased monocyte adhesion to endothelial cells by inducing the expression of intracellular adhesion molecule-1. Consistently, intracellular adhesion molecule-1 expression was significantly upregulated in aortic endothelium of SIRT6-shRNA-treated ApoE(-/-) mice compared with controls. In sum, the aforementioned findings suggest that SIRT6 is a primary negative regulation factor in endothelial dysfunction and atherosclerosis development. As a result, SIRT6 is a promising therapeutic target for treating atherosclerosis and its cardiovascular complications. PMID:26924042

  10. 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

  11. Influences of apolipoprotein E on soluble and heparin-immobilized hepatic lipase

    SciTech Connect

    Landis, B.A.; Rotolo, F.S.; Meyers, W.C.; Clark, A.B.; Quarfordt, S.H.

    1987-06-01

    The effect of human apolipoprotein E (apoE), either alone or in combination with apoC, on the lipolysis of a radiolabeled triglyceride emulsion was studied with hepatic lipase in solution and immobilized on heparin-Sepharose. The soluble hepatic lipase was inhibited, whereas the heparin-immobilized lipase was stimulated by apoE. This stimulation was attenuated by combining apoE with either apoC-II or C-III. The heparin-immobilized lipase demonstrated much less lipolysis of the zwitterionic phosphatidylcholine-stabilized triglyceride emulsion than did the soluble enzyme. This difference was less when the emulsion was stabilized by a nonionic detergent. apoE inhibited lipase activity when assayed under conditions (0.4 M NaCl) of bound enzyme and unbound substrate. Increasing the emulsion apoE content beyond optimum inhibited lipolysis by the immobilized enzyme. Kinetic analysis of phosphatidylcholine-stabilized triglyceride emulsions revealed a significant decrease in immobilized enzyme K/sub m/ and an increase in V/sub max/ when the emulsion was supplemented with apoE. Distributing the immobilized lipase in clustered aggregates produced more lipolysis than when the same enzyme content was uniformly bound.

  12. Apolipoprotein E ε4 allele modulates the immediate impact of acute exercise on prefrontal function.

    PubMed

    De Marco, Matteo; Clough, Peter J; Dyer, Charlotte E; Vince, Rebecca V; Waby, Jennifer S; Midgley, Adrian W; Venneri, Annalena

    2015-01-01

    The difference between Apolipoprotein E ε4 carriers and non-carriers in response to single exercise sessions was tested. Stroop and Posner tasks were administered to young untrained women immediately after walking sessions or moderately heavy exercise. Exercise had a significantly more profound impact on the Stroop effect than on the Posner effect, suggesting selective involvement of prefrontal function. A significant genotype-by-exercise interaction indicated differences in response to exercise between ε4 carriers and non-carriers. Carriers showed facilitation triggered by exercise. The transient executive down-regulation was construed as due to exercise-dependent hypofrontality. The facilitation observed in carriers was interpreted as better management of prefrontal metabolic resources, and explained within the antagonistic pleiotropy hypothesis framework. The findings have implications for the interpretation of differences between ε4 carriers and non-carriers in the benefits triggered by long-term exercise that might depend, at least partially, on mechanisms of metabolic response to physical activity. PMID:25218559

  13. Guanosine effect on cholesterol efflux and apolipoprotein E expression in astrocytes.

    PubMed

    Ballerini, Patrizia; Ciccarelli, Renata; Di Iorio, Patrizia; Buccella, Silvana; D'Alimonte, Iolanda; Giuliani, Patricia; Masciulli, Arianna; Nargi, Eleonora; Beraudi, Alina; Rathbone, Michel P; Caciagli, Francesco

    2006-11-01

    The main source of cholesterol in the central nervous system (CNS) is represented by glial cells, mainly astrocytes, which also synthesise and secrete apolipoproteins, in particular apolipoprotein E (ApoE), the major apolipoprotein in the brain, thus generating cholesterol-rich high density lipoproteins (HDLs). This cholesterol trafficking, even though still poorly known, is considered to play a key role in different aspects of neuronal plasticity and in the stabilisation of synaptic transmission. Moreover, cell cholesterol depletion has recently been linked to a reduction in amyloid beta formation. Here we demonstrate that guanosine, which we previously reported to exert several neuroprotective effects, was able to increase cholesterol efflux from astrocytes and C6 rat glioma cells in the absence of exogenously added acceptors. In this effect the phosphoinositide 3 kinase/extracellular signal-regulated kinase 1/2 (PI3K/ERK1/2) pathway seems to play a pivotal role. Guanosine was also able to increase the expression of ApoE in astrocytes, whereas it did not modify the levels of ATP-binding cassette protein A1 (ABCA1), considered the main cholesterol transporter in the CNS. Given the emerging role of cholesterol balance in neuronal repair, these effects provide evidence for a role of guanosine as a potential pharmacological tool in the modulation of cholesterol homeostasis in the brain. PMID:18404467

  14. Silence of NLRP3 Suppresses Atherosclerosis and Stabilizes Plaques in Apolipoprotein E-Deficient Mice

    PubMed Central

    Zheng, Fei; Xing, Shanshan; Gong, Zushun; Mu, Wei; Xing, Qichong

    2014-01-01

    Objectives. The role of the NLRP3 inflammasome in atherosclerosis remains controversial. The aim of this study was to determine whether inhibition of NLRP3 signaling by lentivirus-mediated RNA interference could reduce atherosclerosis and stabilizes plaques. We also tried to explore the mechanisms of the impact of NLRP3 inflammasome on atherosclerosis. Methods. Apolipoprotein E-deficient mice aged 8 weeks were fed a high-fat diet and were injected with NLRP3 interfering or mock viral suspension after 4 weeks. Lentivirus transfer was repeated in 2 weeks. Four weeks after the first lentivirus injection, we evaluated the effects of NLRP3 gene silencing on plaque composition and stability and on cholesterol efflux and collagen metabolism, by histopathologic analyses and real-time PCR. Results. Gene silence of NLRP3 prevented plaques progression and inhibited inductions of proinflammatory cytokines. Moreover, this RNA interference reduced plaque content of macrophages and lipid, and increased plaque content of smooth muscle cells and collagen, leading to the stabilizing of atherosclerotic plaques. Conclusions. NLRP3 inflammasomes may play a vital role in atherosclerosis, and lentivirus-mediated NLRP3 silencing would be a new strategy to inhibit plaques progression and to reduce local inflammation. PMID:24999295

  15. RNA Interference of Myocyte Enhancer Factor 2A Accelerates Atherosclerosis in Apolipoprotein E-Deficient Mice

    PubMed Central

    Zhao, Yu-xia; Liu, Gang-qiong; Zhang, Jin-ying

    2015-01-01

    Objective Myocyte enhancer factor-2A (MEF 2A) has been shown to be involved in atherosclerotic lesion development, but its role in preexisting lesions is still unclear. In the present study we aim to assess the role of MEF 2A in the progression of pre-existing atherosclerosis. Methods Eighty apolipoprotein E-deficient mice (APOE KO) were randomly allocated to control, scramble and MEF 2A RNA interference (RNAi) groups, and constrictive collars were used to induce plaque formation. Six weeks after surgery, lentiviral shRNA construct was used to silence the expression of MEF 2A. Carotid plaques were harvested for analysis 4 weeks after viral vector transduction. Inflammatory gene expression in the plasma and carotid plaques was determined by using ELISAs and real-time RT-PCR. Results The expression level of MEF 2A was significantly reduced in plasma and plaque in the RNAi group, compared to the control and NC groups, whereas the expression level of pro-inflammatory cytokines was markedly increased. Silencing MEF 2A using lentiviral shRNA significantly reduced the plaque collagen content and fibrous cap thickness, as well as increased plaque area. However, silencing MEF 2A had no obvious effect on plaque lipid content. Conclusions Lentivirus-mediated MEF 2A shRNA accelerates inflammation and atherosclerosis in APOE KO mice, but has no effect on lipoprotein levels in plasma. PMID:25793529

  16. Apolipoprotein E Gene Polymorphisms in Saudi Patients with Systemic Lupus Erythematosus

    PubMed Central

    Al-Rayes, Hannan; Huraib, Ghaleb; Julkhuf, Saeed; Arfin, Misbahul; Tariq, Mohammad; Al-Asmari, Abdulrahman

    2016-01-01

    Apolipoprotein E (APOE) is a glycosylated protein with multiple biological properties. APOE gene polymorphism plays a central role in lipid metabolism and has recently been suggested to regulate inflammation. Our objective is to evaluate whether APOE polymorphism affects susceptibility to SLE. APOE genotyping was performed using ApoE StripAssay™ kit. Results indicated significantly higher frequencies of allele ε4 and genotype ε3/ε4 and lower frequencies of allele ε3 and genotype ε3/ε3 in SLE patients than controls. APOE ε2 allele was found in three patients, whereas it was absent in controls. The frequencies of allele ε4 and genotype ε3/ε4 were significantly higher in SLE patients with renal involvement and those of alleles ε2, ε4 and genotypes ε2/ε3, ε3/ε4 were higher in patients with neuropsychiatric symptoms. It is concluded that APOE allele ε4 is associated with susceptibility risk/clinical manifestations of SLE and ε2 may increase its severity while ε3 is protective for SLE in Saudis. PMID:27257397

  17. 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. PMID:26898714

  18. 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. PMID:27297104

  19. Apolipoprotein E Is a Ligand for Triggering Receptor Expressed on Myeloid Cells 2 (TREM2).

    PubMed

    Atagi, Yuka; Liu, Chia-Chen; Painter, Meghan M; Chen, Xiao-Fen; Verbeeck, Christophe; Zheng, Honghua; Li, Xia; Rademakers, Rosa; Kang, Silvia S; Xu, Huaxi; Younkin, Steven; Das, Pritam; Fryer, John D; Bu, Guojun

    2015-10-23

    Several heterozygous missense mutations in the triggering receptor expressed on myeloid cells 2 (TREM2) have recently been linked to risk for a number of neurological disorders including Alzheimer disease (AD), Parkinson disease, and frontotemporal dementia. These discoveries have re-ignited interest in the role of neuroinflammation in the pathogenesis of neurodegenerative diseases. TREM2 is highly expressed in microglia, the resident immune cells of the central nervous system. Along with its adaptor protein, DAP12, TREM2 regulates inflammatory cytokine release and phagocytosis of apoptotic neurons. Here, we report apolipoprotein E (apoE) as a novel ligand for TREM2. Using a biochemical assay, we demonstrated high-affinity binding of apoE to human TREM2. The functional significance of this binding was highlighted by increased phagocytosis of apoE-bound apoptotic N2a cells by primary microglia in a manner that depends on TREM2 expression. Moreover, when the AD-associated TREM2-R47H mutant was used in biochemical assays, apoE binding was vastly reduced. Our data demonstrate that apoE-TREM2 interaction in microglia plays critical roles in modulating phagocytosis of apoE-bound apoptotic neurons and establish a critical link between two proteins whose genes are strongly linked to the risk for AD. PMID:26374899

  20. Apolipoprotein E: non-cognitive symptoms and cognitive decline in late onset Alzheimer's disease.

    PubMed Central

    Holmes, C; Levy, R; McLoughlin, D M; Powell, J F; Lovestone, S

    1996-01-01

    OBJECTIVES: To determine the association between the epsilon2 and epsilon4 alleles of apolipoprotein E (ApoE) and independent measures of cognitive decline and non-cognitive symptomatology in late onset Alzheimer's disease. METHODS: The frequency of the epsilon2 and epsilon4 alleles of ApoE and their association with measures of cognitive decline and non-cognitive symptomatology were assessed in a population based case register study of 164 patients with late onset Alzheimer's disease from the east Lambeth and south Southwark districts of south London. RESULTS: Analysis of a wide range of non-cognitive symptoms against ApoE epsilon4 genotype showed no significant association but a positive relation was found between ApoE epsilon2 genotype and depressive symptomatology (P = 0.004). No relation was found between measurements of cognitive decline and the presence of the ApoE epsilon4 allele. A trend for decreasing age at onset of 3 to 4 years in carriers of the ApoE epsilon4 allele was found, confirming earlier studies. CONCLUSION: Presence of the epsilon4 allele of ApoE is associated with an earlier age at onset but does not seem to be related to either a more severe psychopathology or a more rapid progression of the illness. The epsilon2 allele of ApoE is associated with depressive symptomatology in late onset Alzheimer's disease. PMID:8971103

  1. Meta-analysis of apolipoprotein E levels in the cerebrospinal fluid of patients with Alzheimer's disease.

    PubMed

    Talwar, Puneet; Sinha, Juhi; Grover, Sandeep; Agarwal, Rachna; Kushwaha, Suman; Srivastava, M V Padma; Kukreti, Ritushree

    2016-01-15

    The possible association between Apolipoprotein E (ApoE) levels in the cerebrospinal fluid (CSF) and Alzheimer's disease (AD) has been studied extensively. However, previous findings have been inconsistent. We conducted a meta-analysis of observational studies, seeking to provide insights into ApoE's potential as a biomarker for AD. A systematic literature search of PubMed (MEDLINE), EMBASE, and Web of Science was performed to retrieve relevant studies evaluating ApoE levels in CSF from AD subjects and controls. The association between ApoE levels in the CSF and AD was estimated by the weighted mean difference (WMD) and 95% confidence interval (CI) using a random-effect model. We identified 24 studies that included 1064AD cases and 1338 non-demented controls. Although the pooled WMD did not indicate a significant association between AD and ApoE levels (-0.30mg/l; 95% CI: -0.69 to 0.09; P=0.13), sub-group analysis controlling for patient sample size (n≥43) revealed significantly lower ApoE levels (WMD: -0.66mg/l; 95% CI: -1.02 to -0.31; P=0.0002) among patients with AD than in controls. Publication bias was absent and sensitivity analysis did not result in any significant change in the pooled estimates, indicating highly stable results. The present meta-analysis indicates the potential of CSF ApoE levels as a predictor of AD association. PMID:26723997

  2. 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. PMID:25749341

  3. Epigenetic Control of Apolipoprotein E Expression Mediates Gender-Specific Hematopoietic Regulation.

    PubMed

    Vasanthakumar, Aparna; Zullow, Hayley; Lepore, Janet B; Thomas, Kenya; Young, Natalie; Anastasi, John; Reardon, Catherine A; Godley, Lucy A

    2015-12-01

    Epigenetic alterations play a central role in the control of normal and malignant blood cell development. We demonstrate here that expression of a truncated DNA methyltransferase 3B isoform DNMT3B7, which has been shown to alter cellular epigenetic patterns, decreases the overall number of hematopoietic stem and progenitor cells (HSPCs), and markedly diminishes blood cell reconstitution within the female hormonal microenvironment. Gene expression profiling of HSPCs isolated from DNMT3B7 transgenic embryos identified Apolipoprotein E (Apoe) as overexpressed. The CpG island controlling Apoe expression had lower levels of modified cytosines in DNMT3B7 transgenic HSPCs, corresponding with the observed increase in gene expression. Furthermore, we observed that spleens and bone marrows of female mice transplanted with DNMT3B7 transgenic HSPCs express very high levels of Apoe. Finally, the introduction of Apoe-overexpressing HSPCs into male recipients decreased bone marrow engraftment, recapitulating our original observations in female recipients. Our work reveals a dynamic interplay between the intrinsic epigenetic changes in HSPCs and extrinsic endocrine factors acting on these cells to regulate the efficiency of HSPC engraftment and reconstitution. We have identified a novel mechanism by which gender-specific hormones modulate HSPC function, which could serve as a target for augmenting hematopoiesis in cases with limited HSC functionality. PMID:26417967

  4. The Fat-Fed Apolipoprotein E Knockout Mouse Brachiocephalic Artery in the Study of Atherosclerotic Plaque Rupture

    PubMed Central

    Bond, Andrew R.; Jackson, Christopher L.

    2011-01-01

    Atherosclerosis has been studied in animals for almost a century, yet the events leading up to the rupture of an atherosclerotic plaque (the underlying cause of the majority of fatal thrombosis formation) have only been studied in the past decade, due in part to the development of a mouse model of spontaneous plaque rupture. Apolipoprotein E knockout mice, when fed a high-fat diet, consistently develop lesions in the brachiocephalic artery that rupture at a known time point. It is therefore now possible to observe the development of lesions to elucidate the mechanisms behind the rupture of plaques. Critics argue that the model does not replicate the appearance of human atherosclerotic plaque ruptures. The purpose of this review is to highlight the reasons why we should be looking to the apolipoprotein E knockout mouse to further our understanding of plaque rupture. PMID:21076539

  5. Solid lipid nanoparticles as a vehicle for brain-targeted drug delivery: two new strategies of functionalization with apolipoprotein E.

    PubMed

    Neves, Ana Rute; Queiroz, Joana Fontes; Weksler, Babette; Romero, Ignacio A; Couraud, Pierre-Olivier; Reis, Salette

    2015-12-11

    Nanotechnology can be an important tool to improve the permeability of some drugs for the blood-brain barrier. In this work we created a new system to enter the brain by functionalizing solid lipid nanoparticles with apolipoprotein E, aiming to enhance their binding to low-density lipoprotein receptors on the blood-brain barrier endothelial cells. Solid lipid nanoparticles were successfully functionalized with apolipoprotein E using two distinct strategies that took advantage of the strong interaction between biotin and avidin. Transmission electron microscopy images revealed spherical nanoparticles, and dynamic light scattering gave a Z-average under 200 nm, a polydispersity index below 0.2, and a zeta potential between -10 mV and -15 mV. The functionalization of solid lipid nanoparticles with apolipoprotein E was demonstrated by infrared spectroscopy and fluorimetric assays. In vitro cytotoxic effects were evaluated by MTT and LDH assays in the human cerebral microvascular endothelial cells (hCMEC/D3) cell line, a human blood-brain barrier model, and revealed no toxicity up to 1.5 mg ml(-1) over 4 h of incubation. The brain permeability was evaluated in transwell devices with hCMEC/D3 monolayers, and a 1.5-fold increment in barrier transit was verified for functionalized nanoparticles when compared with non-functionalized ones. The results suggested that these novel apolipoprotein E-functionalized nanoparticles resulted in dynamic stable systems capable of being used for an improved and specialized brain delivery of drugs through the blood-brain barrier. PMID:26574295

  6. 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.

  7. Mutations of the domain forming the dimeric interface of the ArdA protein affect dimerization and antimodification activity but not antirestriction activity

    PubMed Central

    Roberts, Gareth A; Chen, Kai; Bower, Edward K M; Madrzak, Julia; Woods, Arcadia; Barker, Amy M; Cooper, Laurie P; White, John H; Blakely, Garry W; Manfield, Iain; Dryden, David T F

    2013-01-01

    ArdA antirestriction proteins are encoded by genes present in many conjugative plasmids and transposons within bacterial genomes. Antirestriction is the ability to prevent cleavage of foreign incoming DNA by restriction-modification (RM) systems. Antimodification, the ability to inhibit modification by the RM system, can also be observed with some antirestriction proteins. As these mobile genetic elements can transfer antibiotic resistance genes, the ArdA proteins assist their spread. The consequence of antirestriction is therefore the enhanced dissemination of mobile genetic elements. ArdA proteins cause antirestriction by mimicking the DNA structure bound by Type I RM enzymes. The crystal structure of ArdA showed it to be a dimeric protein with a highly elongated curved cylindrical shape [McMahon SA et al. (2009) Nucleic Acids Res37, 4887–4897]. Each monomer has three domains covered with negatively charged side chains and a very small interface with the other monomer. We investigated the role of the domain forming the dimer interface for ArdA activity via site-directed mutagenesis. The antirestriction activity of ArdA was maintained when up to seven mutations per monomer were made or the interface was disrupted such that the protein could only exist as a monomer. The antimodification activity of ArdA was lost upon mutation of this domain. The ability of the monomeric form of ArdA to function in antirestriction suggests, first, that it can bind independently to the restriction subunit or the modification subunits of the RM enzyme, and second, that the many ArdA homologues with long amino acid extensions, present in sequence databases, may be active in antirestriction. Structured digital abstract ArdA and ArdA bind by molecular sieving (1, 2) ArdA and ArdA bind by cosedimentation in solution (1, 2) PMID:23910724

  8. 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

    2016-08-01

    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. PMID:27425408

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Quercetin stabilizes apolipoprotein E and reduces brain Aβ levels in amyloid model mice.

    PubMed

    Zhang, Xilin; Hu, Jin; Zhong, Li; Wang, Na; Yang, Longyu; Liu, Chia-Chen; Li, Huifang; Wang, Xin; Zhou, Ying; Zhang, Yunwu; Xu, Huaxi; Bu, Guojun; Zhuang, Jiangxing

    2016-09-01

    Apolipoprotein E (apoE) is a major cholesterol carrier that regulates lipid homeostasis by mediating lipid transport from one tissue or cell type to another. In the central neural system (CNS), apoE is mainly produced by astrocytes, and transports cholesterol to neurons via apoE receptors, which are members of the low-density lipoprotein receptor family. The APOEε4 gene is a strong genetic risk factor for late-onset sporadic Alzheimer's disease (AD), likely through its strong effect on the accumulation of amyloid-β (Aβ) peptide. ApoE protein levels in cerebrospinal fluid (CSF) and plasma are reduced in APOEε4 carriers and in patients with AD. Furthermore, altered cholesterol levels are also associated with the risk of AD. Aβ accumulation, oligomerization and deposition in the brain are central to the pathogenesis of AD. Mounting evidence demonstrates that apoE and apoE receptors play important roles in these processes. Astrocyte-derived apoE is pivotal for cerebral cholesterol metabolism and clearance of Aβ. Thus, we hypothesized that increased apoE in the brain may be an effective therapeutic strategy for AD. We report here that quercetin can significantly increase apoE levels by inhibiting apoE degradation in immortalized astrocytes. Importantly, we show that oral administration of quercetin significantly increased brain apoE and reduced insoluble Aβ levels in the cortex of 5xFAD amyloid model mice. Our results demonstrate that quercetin increases apoE levels through a novel mechanism and can be explored as a novel class of drug for AD therapy. PMID:27114256

  14. 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.

  15. Benzo[a]pyrene Potentiates the Pathogenesis of Abdominal Aortic Aneurysms in Apolipoprotein E Knockout Mice

    PubMed Central

    Prins, Petra A.; Perati, Prudhvidhar R.; Kon, Valentina; Guo, Zhongmao; Ramesh, Aramandla; Linton, MacRae F.; Fazio, Sergio; Sampson, Uchechukwu K.

    2012-01-01

    The objective of this study was to determine the effect of benzo[a]pyrene (BaP), an abundant environmental polycyclic aromatic hydrocarbon compound, on the pathogenesis of abdominal aortic aneurysms (AAA). Earlier studies have shown that BaP promotes vasculopathy, including atherosclerosis, a predisposing factor for AAA development. In two experimental arms, 203 apolipoprotein E knockout (ApoE-/-) mice were evaluated in 4 groups: BaP, angiotensin II (AngII), BaP+AngII and control. Mice in the first arm were exposed to 5mg/kg/week of BaP for 42 days, and in the second arm to 0.71mg/kg daily for 60 days. In arm one, AAA incidence was higher in the BaP+AngII (14/28) versus AngII (8/27) group (p < 0.05), rupture (n=3) was observed only in BaP+AngII treated mice (p < 0.05). In the second arm, AAA incidence did not differ between AngII (17/30) and BaP+AngII (16/29) groups. However, intact AAA diameter was larger in the BaP+AngII (2.3 ± 0.1mm) versus AngII (1.9 ± 0.1mm) group (p < 0.05), but AAA rupture did not differ (p=NS). In both experimental arms, BaP+AngII mice showed increased expression of tumor necrosis factor alpha (TNF-α), cyclophilin A (Cyp A), and matrix metalloproteinase-9 (MMP9) (p < 0.05). No AAA occurred in control or BaP groups. These findings suggest the role of BaP exposure in potentiating AAA pathogenesis, which may have potential public health significance. PMID:22415081

  16. Relevance of apolipoprotein E4 for the lipid profile of Brazilian patients with coronary artery disease.

    PubMed

    Souza, D R S; Nakachima, L; Biagioni, R B; Nakazone, M A; Pinhel, M A S; Trindade, D M; Mafra, V T; Tácito, L H B; Martin, J F V; Pinheiro Júnior, S; Brandão, A C

    2007-02-01

    Apolipoprotein E (apoE - e2, e3, e4 alleles) plays a role in the regulation of lipid metabolism, with the e4 considered to be a risk factor for coronary artery disease (CAD). We aimed to evaluate the apoE polymorphisms in Brazilians with CAD and their influence on the lipid profile and other risk factors (hypertension, diabetes mellitus, smoking). Two hundred individuals were examined: 100 patients with atherosclerosis confirmed by coronary angiography and 100 controls. Blood samples were drawn to determine apoE polymorphisms and lipid profile. As expected, the e3 allele was prevalent in the CAD (0.87) and non-CAD groups (0.81; P = 0.099), followed by the e4 allele (0.09 and 0.14, respectively; P = 0.158). The e3/3 (76 and 78%) and e3/4 (16 and 23%) were the most common genotypes for patients and controls, respectively. The lipid profile was altered in patients compared to controls (P < 0.05), independently of the e4 allele. However, in the controls this allele was prevalent in individuals with elevated LDL-cholesterol levels only (odds ratio = 2.531; 95% CI = 1.028-6.232). The frequency of risk factors was higher in the CAD group (P < 0.05), but their association with the lipid profile was not demonstrable in e4 carriers. In conclusion, the e4 allele is not associated with CAD or lipid profile in patients with atherosclerosis. However, its frequency in the non-CAD group is associated with increased levels of LDL-cholesterol, suggesting an independent effect of the e4 allele on lipid profile when the low frequency of other risk factors in this group is taken into account. PMID:17273655

  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. PMID:26566121

  18. Polymorphism in methylenetetrahydrofolate reductase, plasminogen activator inhibitor-1, and apolipoprotein E in hemodialysis patients.

    PubMed

    Al-Muhanna, Fahad; Al-Mueilo, Samir; Al-Ali, Amein; Larbi, Emmanuel; Rubaish, Abdullah; Abdulmohsen, Mohammed Fakhry; Al-Zahrani, Alhussain; Al-Ateeq, Suad

    2008-11-01

    The methylenetetrahydrofolate reductase (MTHFR) gene polymorphism, apolipoprotein E (apo epsilon4) gene polymorphism and polymorphism of plasminogen activator inhibitor-1 (PAI-1) have been shown to be associated with end-stage renal disease (ESRD). To determine the prevalence of these mutations in Saudi patients with ESRD on hemodialysis, we studied the allelic frequency and genotype distribution in patients receiving hemodialysis and in a control group, all residing in the Eastern Province of Saudi Arabia. The genotypes were determined using allele specific hybridization procedures and were confirmed by restriction fragment length polymorphism. The T allele frequency and homozygous genotype of MTHFR in ESRD patients were 14% and 2.4%, respectively compared to 13.4% and 0%, respectively in the control group. The allele frequency and homozygous genotype of 4G/4G PAI-1 gene polymorphism were 46.4% and 4.8% respectively in ESRD patients compared to 57.1% and 32% respectively in the control group. The apo s4 allele frequency and homozygous genotype distribution in hemodialysis patients were 7% and 2.4%, respectively compared to 13% and 2% in the control group. Although allele frequency of C677T of MTHFR was statistically similar in the hemodialysis patients and in the control group, the homozygotes T allele genotype was over represented in the hemodialysis group compared to normal. The prevalence of PAI-1 4G/4G polymorphism in ESRD patients was lower when compared to the control group. The prevalence of apo s4 allele did not differ significantly between the two groups. The present results demonstrate that all three studied polymorphic mutations are present in our population and that they may contribute to the etiology of the disease in our area. PMID:18974580

  19. 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

  20. 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. PMID:26161964

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

    PubMed Central

    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-fluorodeoxyglu-cose 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. PMID:26161964

  2. 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. PMID:26876367

  3. 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.

  4. Apolipoprotein E Genotype Linked to Spatial Gait Characteristics: Predictors of Cognitive Dual Task Gait Change

    PubMed Central

    MacAulay, Rebecca K.; Allaire, Ted; Brouillette, Robert; Foil, Heather; Bruce-Keller, Annadora J.; Keller, Jeffrey N.

    2016-01-01

    Background Developing measures to detect preclinical Alzheimer’s Disease is vital, as prodromal stage interventions may prove more efficacious in altering the disease’s trajectory. Gait changes may serve as a useful clinical heuristic that precedes cognitive decline. This study provides the first systematic investigation of gait characteristics relationship with relevant demographic, physical, genetic (Apolipoprotein E genotype), and health risk factors in non-demented older adults during a cognitive-load dual task walking condition. Methods The GAITRite system provided objective measurement of gait characteristics in APOE-e4 “carriers” (n = 75) and “non-carriers” (n = 224). Analyses examined stride length and step time gait characteristics during simple and dual-task (spelling five-letter words backwards) conditions in relation to demographic, physical, genetic, and health risk factors. Results Slower step time and shorter stride length associated with older age, greater health risk, and worse physical performance (ps < .05). Men and women differed in height, gait characteristics, health risk factors and global cognition (ps < .05). APOE-e4 associated with a higher likelihood of hypercholesterolemia and overall illness index scores (ps < .05). No genotype-sex interactions on gait were found. APOE-e4 was linked to shorter stride length and greater dual-task related disturbances in stride length. Conclusions Stride length has been linked to heightened fall risk, attention decrements and structural brain changes in older adults. Our results indicate that stride length is a useful behavioral marker of cognitive change that is associated with genetic risk for AD. Sex disparities in motor decline may be a function of health risk factors. PMID:27486898

  5. 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

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

    PubMed

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

    2014-12-01

    Human apolipoprotein E (apoE) isoforms exhibit different conformational stabilities and lipid-binding properties that give rise to altered cholesterol metabolism among the isoforms. Using Trp-substituted mutations and site- directed fluorescence labeling, we made a comprehensive comparison of the conformational organization of the N- and C-terminal domains and lipid interactions between the apoE3 and apoE4 isoforms. Trp fluorescence measurements for selectively Trp-substituted variants of apoE isoforms demonstrated that apoE4 adopts less stable conformations in both the N- and C-terminal domains compared to apoE3. Consistent with this, the conformational reorganization of the N-terminal helix bundle occurs at lower guanidine hydrochloride concentration in apoE4 than in apoE3 as monitored by fluorescence resonance energy transfer (FRET) from Trp residues to acrylodan attached at the N-terminal helix. Upon binding of apoE3 and apoE4 variants to egg phosphatidylcholine small unilamellar vesicles, similar changes in Trp fluorescence or FRET efficiency were observed for the isoforms, indi- cating that the opening of the N-terminal helix bundle occurs similarly in apoE3 and apoE4. Introduction of mutations into the C-terminal domain of the apoE isoforms to prevent self-association and maintain the monomeric state resulted in great increase in the rate of binding of the C-terminal helices to a lipid surface. Overall, our results demonstrate that the different conformational organizations of the N- and C-terminal domains have a minor effect on the steady-state lipid-binding behavior of apoE3 and apoE4: rather, self-association property is a critical determinant in the kinetics of lipid binding through the C-terminal helices of apoE isoforms. PMID:25281910

  7. Fluorescence Study of Domain Structure and Lipid Interaction of Human Apolipoproteins E3 and E4

    PubMed Central

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

    2014-01-01

    Human apolipoprotein E (apoE) isoforms exhibit different conformational stabilities and lipid-binding properties that give rise to altered cholesterol metabolism among the isoforms. Using Trp-substituted mutations and site-directed fluorescence labeling, we made a comprehensive comparison of the conformational organization of the N- and C-terminal domains and lipid interactions between the apoE3 and apoE4 isoforms. Trp fluorescence measurements for selectively Trp-substituted variants of apoE isoforms demonstrated that apoE4 adopts less stable conformations in both the N- and C-terminal domains compared to apoE3. Consistent with this, the conformational reorganization of the N-terminal helix bundle occurs at lower guanidine hydrochloride concentration in apoE4 than in apoE3 as monitored by fluorescence resonance energy transfer (FRET) from Trp residues to acrylodan attached at the N-terminal helix. Upon binding of apoE3 and apoE4 variants to egg phosphatidylcholine small unilamellar vesicles, similar changes in Trp fluorescence or FRET efficiency were observed for the isoforms, indicating that opening of the N-terminal helix bundle occurs similarly in apoE3 and apoE4. Introduction of mutations into the C-terminal domain of the apoE isoforms to prevent self-association and maintain the monomeric state resulted in great increase in the rate of binding of the C-terminal helices to a lipid surface. Overall, our results demonstrate that the different conformational organizations of the N- and C-terminal domains have a minor effect on the steady-state lipid-binding behavior of apoE3 and apoE4: rather, self-association property is a critical determinant in the kinetics of lipid binding through the C-terminal helices of apoE isoforms. PMID:25281910

  8. 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. PMID:25619771

  9. 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

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

    PubMed

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

    2016-08-01

    Carrying at least one apolipoprotein E ε4 allele (E4+) is the main genetic risk factor for Alzheimer's disease (AD). Epidemiological studies support that consuming fatty fish rich in docosahexaenoic acid (DHA; 22:6ω3) is protective against development of AD. However, this protective effect seems not to hold in E4+. The involvement of APOE genotype on the relationship between DHA intake and cognitive decline could be mediated through cholesterol. Many studies show a link between cholesterol metabolism and AD progression. In this study, we investigated whether cholesterol metabolism is improved in E3+ and E4+ mice consuming a diet rich in DHA. Plasma cholesterol was 36% lower in E4+ mice compared to E3+ mice fed the control diet (P=.02), and in the liver, there was a significant genotype effect where cholesterol levels were 18% lower in E4+ mice than E3+ mice. The low-density lipoprotein receptor was overexpressed in the liver of E4+ mice. Plasma cholesterol levels were 33% lower after the DHA diet (P=.02) in E3+ mice only, and there was a significant diet effect where cholesterol level was 67% lower in the liver of mice fed DHA. Mice fed the DHA diet also had 62% less lipolysis stimulated lipoprotein receptor expression in the liver compared to mice fed the control diet (P<.0001), but there was no genotype effect. These findings suggest that plasma and liver cholesterol homeostasis and the receptors regulating uptake of cholesterol in the liver are modulated differently and independently by APOE allele and DHA intake. PMID:27239755

  11. 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

  12. Diet-induced hyperlipoproteinemia and atherosclerosis in apolipoprotein E3-Leiden transgenic mice.

    PubMed Central

    van Vlijmen, B J; van den Maagdenberg, A M; Gijbels, M J; van der Boom, H; HogenEsch, H; Frants, R R; Hofker, M H; Havekes, L M

    1994-01-01

    Apolipoprotein E3-Leiden (APOE*3-Leiden) transgenic mice have been used to study the effect of different cholesterol-containing diets on the remnant lipoprotein levels and composition and on the possible concurrent development of atherosclerotic plaques. On high fat/cholesterol (HFC) diet, the high expressing lines 2 and 181 developed severe hypercholesterolemia (up to 40 and 60 mmol/liter, respectively), whereas triglyceride levels remained almost normal when compared with regular mouse diet. The addition of cholate increased the hypercholesterolemic effect of this diet. In lines 2 and 181, serum levels of apo E3-Leiden also increased dramatically upon cholesterol feeding (up to 107 and 300 mg/dl, respectively). In these high expressing APOE*3-Leiden transgenic mice, the increase in both serum cholesterol and apo E3-Leiden occurred mainly in the VLDL/LDL-sized fractions, whereas a considerable increase in large, apo E-rich HDL particles also occurred. In contrast to the high expressing lines, the low expressing line 195 reacted only mildly upon HFC diet. On HFC diets, the high expresser APOE*3-Leiden mice developed atherosclerotic lesions in the aortic arch, the descending aorta, and the carotid arteries, varying from fatty streaks containing foam cells to severe atherosclerotic plaques containing cholesterol crystals, fibrosis, and necrotic calcified tissue. Quantitative evaluation revealed that the atherogenesis is positively correlated with the serum level of cholesterol-rich VLDL/LDL particles. In conclusion, with APOE*3-Leiden transgenic mice, factors can be studied that influence the metabolism of remnant VLDL and the development of atherosclerosis. Images PMID:8163645

  13. Association of apolipoprotein E polymorphisms with cerebral vasospasm after spontaneous subarachnoid hemorrhage.

    PubMed

    Wu, Hai-tao; Zhang, Xiao-dong; Su, Hai; Jiang, Yong; Zhou, Shuai; Sun, Xiao-chuan

    2011-01-01

    Cerebral vasospasm (CVS) is the main complication of spontaneous subarachnoid hemorrhage (SAH), severely affecting clinical outcome of patients with SAH. Apolipoprotein E gene (APOE) is associated with prognosis of spontaneous subarachnoid hemorrhage (SAH), and APOEε4 allele is reported to be apt to CVS after SAH. The current study aimed to investigate the association of APOE polymorphisms with CVS after SAH. One hundred and eighty-five patients with spontaneous SAH were recruited in the study. APOE genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). CVS was judged by Transcranial Doppler sonography (TCD) combined with patients' condition. χ2-test and logistic regression analysis were done by SPSS (version 11.5). The distributions of APOE genotypes and alleles matched Hardy-Weinberg Law. In 185 patients, 21 of 32 (65.7%) patients with APOEε4 allele showed CVS, which was significantly different from those without APOE ε4 allele (56 of 153 patients, 36.6%, P=0.022). However, neither the presence of ε2 nor ε3 was significantly different from those absent of it (P>0.05). Logistic regression analysis demonstrated that ApoEε4 allele was a risk factor (OR=2.842. 95% CI 1.072-6.124. P=0.019) to predispose to CVS after adjusting for age, sex, hypertension or not, hyperlipemia or not, Fisher grade, and Hunt-Hess grade after SAH. Our finding suggests that the patients with APOEε4 allele predispose to CVS after spontaneous SAH. PMID:21116929

  14. Functional Network Endophenotypes Unravel the Effects of Apolipoprotein E Epsilon 4 in Middle-Aged Adults

    PubMed Central

    Chen, Gang; Li, Wenjun; Ward, B. Douglas; Franczak, Malgorzata B.; Jones, Jennifer L.; Antuono, Piero G.; Li, Shi-Jiang

    2013-01-01

    Apolipoprotein E-ε4 (APOE-ε4) accentuates memory decline, structural volume loss and cerebral amyloid deposition in cognitively healthy adults. We investigated whether APOE-ε4 carriers will show disruptions in the intrinsic cognitive networks, including the default mode (DMN), executive control (ECN) and salience (SN) networks, relative to noncarriers in middle-aged healthy adults; and the extent to which episodic-memory performance is related to the altered functional connectivity (Fc) in these networks. Resting-state functional connectivity MRI (R-fMRI) was used to measure the differences in the DMN, ECN and SN Fc between 20 APOE-ε4 carriers and 26 noncarriers. Multiple linear regression analyses were performed to determine the relationship between episodic-memory performance and Fc differences in the three resting-state networks across all subjects. There were no significant differences in the demographic and neuropsychological characteristics and the gray-matter volumes in the carriers and noncarriers. While mostly diminished DMN and ECN functional connectivities were seen, enhanced connections to the DMN structures were found in the SN in ε4 carriers. Altered DMN and ECN were associated with episodic memory performance. Significant Fc differences in the brain networks implicated in cognition were seen in middle-aged individuals with a genetic risk for AD, in the absence of cognitive decline and gray-matter atrophy. Prospective studies are essential to elucidate the potential of R-fMRI technique as a biomarker for predicting conversion from normal to early AD in healthy APOE-ε4 carriers. PMID:23424640

  15. Secreted apolipoprotein E reduces macrophage-mediated LDL oxidation in an isoform-dependent way.

    PubMed

    Mabile, Laurence; Lefebvre, Chantal; Lavigne, Jacques; Boulet, Lucie; Davignon, Jean; Lussier-Cacan, Suzanne; Bernier, Lise

    2003-11-01

    As an inflammatory cell, the macrophage produces various oxidizing agents, such as free radical species. These can modify LDL as a secondary effect and doing so may favor atherogenic processes. Any molecule able to counteract these reactions would be of much benefit, especially if secreted by the macrophage itself at the lesion site. Such is the case for apolipoprotein E (apoE), which has been shown to exert antioxidant properties in some studies, mostly in relation to Alzheimer's disease. In this study, we assessed the antioxidant potential of the various isoforms of apoE (E2, E3, and E4) using a metal-induced LDL oxidation system with exogenous recombinant apoE and an in vitro model of macrophage-mediated LDL oxidation. We found that all three isoforms had an antioxidant capacity. However, whereas apoE2 was the most protective isoform in the cell-free system, the opposite was observed in apoE-transfected J774 macrophages. In the latter model, cellular cholesterol efflux was found to be more important with apoE2, possibly explaining the larger quantity of oxidative indices observed in the medium. It is proposed that the antioxidant property of apoE results from a balance between direct apoE antioxidant capacities, such as the ability to trap free radicals, and potentially pro-oxidative indirect events associated with cholesterol efflux from cells. Our observations add to the therapeutic potential of apoE. However, they also suggest the need for more experiments in order to achieve careful selection of the apoE isoform to be targeted, especially in the perspective of apoE transgene use. PMID:14587032

  16. Transgenic human C-reactive protein is not proatherogenic in apolipoprotein E-deficient mice

    PubMed Central

    Hirschfield, Gideon M.; Gallimore, J. Ruth; Kahan, Melvyn C.; Hutchinson, Winston L.; Sabin, Caroline A.; Benson, G. Martin; Dhillon, Amar P.; Tennent, Glenys A.; Pepys, Mark B.

    2005-01-01

    The association between circulating concentrations of C-reactive protein (CRP) and future atherothrombotic events has provoked speculation about a possible pathogenetic role of CRP. However, we show here that transgenic expression of human CRP had no effect on development, progression, or severity of spontaneous atherosclerosis, or on morbidity or mortality, in male apolipoprotein E (apoE)-deficient C57BL/6 mice up to 56 weeks, despite deposition of human CRP and mouse complement component 3 in the plaques. Although female apoE knockouts develop atherosclerosis more rapidly than males, the human CRP transgene is under sex hormone control and is expressed at human levels only in males. We therefore studied only male mice. The concentration of mouse serum amyloid P component, an extremely sensitive systemic marker of inflammation, remained normal throughout except for transient spikes in response to fighting in a few animals, indicating that atherogenesis in this model is not associated with an acute-phase response. However, among human CRP transgenic mice, the circulating CRP concentration was higher in apoE knockouts than in wild-type controls. The higher CRP values were associated with substantially lower estradiol concentrations in the apoE-deficient animals. Human CRP transgene expression is thus up-regulated in apoE-deficient mice, apparently reflecting altered estrogen levels, despite the absence of other systemic signs of inflammation. Extrapolation to human pathology from this xenogeneic combination of human CRP with apoE deficiency-mediated mouse atherosclerosis must be guarded. Nevertheless, the present results do not suggest that human CRP is either proatherogenic or atheroprotective in vivo. PMID:15919817

  17. Up-regulation of apolipoprotein E by leptin in the hypothalamus of mice and rats

    PubMed Central

    Shen, Ling; Tso, Patrick; Wang, David Q.-H.; Woods, Stephen C.; Davidson, W. Sean; Sakai, Randall; Liu, Min

    2009-01-01

    Apolipoprotein E (apoE) is a satiation factor, playing an important role in the regulation of food intake and body weight. We previously reported that apoE was present in the hypothalamus, but it is unclear which type of the cells in this brain area expressing apoE. In addition, hypothalamic apoE mRNA levels were significantly reduced in both genetically obese ob/ob (leptin deficient) mice and high-fat diet-induced obese (leptin resistant) rats, raising the possibility that deficient leptin signaling might be related to the change in apoE gene expression. In the present studies, using double-staining immunohistochemistry, we demonstrated that apoE is mainly present in astrocytes. To characterize the effect of leptin on apoE gene expression, ob/ob and db/db mice were treated with recombinant mouse leptin (3 μg/g daily, i.p.) or vehicle for 5 days. We found that the increased hypothalamic apoE mRNA levels occurred only in leptin-treated ob/ob, but not in pair-fed ob/ob, or db/db, mice, indicating that leptin up-regulated hypothalamic apoE gene expression depends upon an intact leptin receptor, and this effect is not related to the changes in food intake and body weight. The reduced apoE gene expression caused by fasting, which also results in relatively lower leptin level, is restored by intracerebroventricular administration of leptin. In addition, leptin was significantly less efficacious in apoE KO mice because these animals consumed more food and lost less weight following leptin treatment, compared with wild-type controls. These observations imply that apoE signaling, at least partially, mediates the inhibitory effects of leptin on feeding. PMID:19481557

  18. Protein Kinase C Controls Vesicular Transport and Secretion of Apolipoprotein E from Primary Human Macrophages*

    PubMed Central

    Karunakaran, Denuja; Kockx, Maaike; Owen, Dylan M.; Burnett, John R.; Jessup, Wendy; Kritharides, Leonard

    2013-01-01

    Macrophage-specific apolipoprotein E (apoE) secretion plays an important protective role in atherosclerosis. However, the precise signaling mechanisms regulating apoE secretion from primary human monocyte-derived macrophages (HMDMs) remain unclear. Here we investigate the role of protein kinase C (PKC) in regulating basal and stimulated apoE secretion from HMDMs. Treatment of HMDMs with structurally distinct pan-PKC inhibitors (calphostin C, Ro-31-8220, Go6976) and a PKC inhibitory peptide all significantly decreased apoE secretion without significantly affecting apoE mRNA or apoE protein levels. The PKC activator phorbol 12-myristate 13-acetate (PMA) stimulated apoE secretion, and both PMA-induced and apoAI-induced apoE secretion were inhibited by PKC inhibitors. PKC regulation of apoE secretion was found to be independent of the ATP binding cassette transporter ABCA1. Live cell imaging demonstrated that PKC inhibitors inhibited vesicular transport of apoE to the plasma membrane. Pharmacological or peptide inhibitor and knockdown studies indicate that classical isoforms PKCα/β and not PKCδ, -ϵ, -θ, or -ι/ζ isoforms regulate apoE secretion from HMDMs. The activity of myristoylated alanine-rich protein kinase C substrate (MARCKS) correlated with modulation of PKC activity in these cells, and direct peptide inhibition of MARCKS inhibited apoE secretion, implicating MARCKS as a downstream effector of PKC in apoE secretion. Comparison with other secreted proteins indicated that PKC similarly regulated secretion of matrix metalloproteinase 9 and chitinase-3-like-1 protein but differentially affected the secretion of other proteins. In conclusion, PKC regulates the secretion of apoE from primary human macrophages. PMID:23288845

  19. An updated meta-analysis: Apolipoprotein E genotypes and risk of primary open-angle glaucoma

    PubMed Central

    Liao, Rongfeng; Ye, Minjie

    2014-01-01

    Purpose To study the association of apolipoprotein E (APOE) polymorphisms and primary open-angle glaucoma (POAG). Methods After a systematic literature search, all relevant studies evaluating the association between APOE polymorphisms and POAG were included. All statistical tests were calculated with Stata 11.0. Results Twelve independent studies on the APOE gene (1,971 cases, 1,756 controls) and POAG were included. A significant association between the APOE gene and POAG was found in the genetic model of ε4/ε4 versus ε3/ε3 (odds ratio [OR] = 2.09, 95% confidence interval [CI] = 1.12–3.88, p = 0.02). However, no association was detected in the models of ε2/ε2 versus ε3/ε3, ε2/ε3 versus ε3/ε3, ε2/ε4 versus ε3/ε3, ε3/ε4 versus ε3/ε3, allele ε2 versus allele ε3, and allele ε4 versus allele ε3. Subgroup analyses showed that a statistically significant association between the APOE gene and the risk of POAG existed in the genetic model of ε4/ε4 versus ε3/ε3 in Asians (OR = 3.55, 95% CI = 1.06–11.87, p = 0.04). No association was identified between the APOE gene and the risk of POAG in Caucasians. Conclusions The present meta-analysis indicated that the ε4/ε4 genotype is associated with increased risk of POAG in Asians. PMID:25053873

  20. Apolipoprotein E polymorphism is associated with susceptibility to schizophrenia among Saudis

    PubMed Central

    Al-Asmary, Saeed Mohammad; Kadasah, Saeed; Arfin, Misbahul; Tariq, Mohammad

    2015-01-01

    Introduction Apolipoprotein E (APOE) genotypes influence the phenotype of several neurodegenerative disorders including Alzheimer's and Parkinson disease and may affect schizophrenia pathogenesis. This study was undertaken to determine the association between APOE gene polymorphisms and schizophrenia in the Saudi population. Material and methods APOE allele and genotype frequencies were studied in 380 Saudi subjects including schizophrenia patients and matched controls using polymerase chain reaction (PCR) and reverse-hybridization techniques. Results The frequencies of the APOE allele ε2 and genotypes ε2/ε3 and ε2/ε4 were significantly higher in the schizophrenia patients as compared to controls, suggesting that the ε2 allele and its heterozygous genotypes may increase the susceptibility to schizophrenia. In contrast, the frequencies of the ε3 allele and ε3/ε3 genotype were lower in patients as compared to controls, suggesting a protective effect of APOE ε3 for schizophrenia. This study indicated that APOE ε4 was differentially associated with schizophrenia depending on the symptoms as the frequency of the ε4 allele was significantly higher in schizophrenia patients with positive symptoms. By contrast, no significant association between APOE ε4 and schizophrenia patients with negative symptoms was observed. Genotypes ε2/ε2 and ε4/ε4 were absent in patients and controls. Moreover, the age of onset was significantly lower in patients with the APOE ε2/ε3 genotype. There was no significant difference in the frequencies of APOE alleles and genotypes between male and female schizophrenia patients. Conclusions The results of this study clearly show that APOE alleles and genotypes are associated with risk of developing schizophrenia and early age of onset in Saudis. PMID:26322100

  1. 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. PMID:16103669

  2. The Ras G Domain Lacks the Intrinsic Propensity to Form Dimers.

    PubMed

    Kovrigina, Elizaveta A; Galiakhmetov, Azamat R; Kovrigin, Evgenii L

    2015-09-01

    Ras GTPase is a molecular switch controlling a number of cellular pathways including growth, proliferation, differentiation, and apoptosis. Recent reports indicated that Ras undergoes dimerization at the membrane surface through protein-protein interactions. If firmly established this property of Ras would require profound reassessment of a large amount of published data and modification of the Ras signaling paradigm. One proposed mechanism of dimerization involves formation of salt bridges between the two GTPase domains (G domains) leading to formation of a compact dimer as observed in Ras crystal structures. In this work, we interrogated the intrinsic ability of Ras to self-associate in solution by creating conditions of high local concentration through irreversibly tethering the two G domains together at their unstructured C-terminal tails. We evaluated possible self-association in this inverted tandem conjugate via analysis of the time-domain fluorescence anisotropy and NMR chemical shift perturbations. We did not observe the increased rotational correlation time expected for the G domain dimer. Variation of the ionic strength (to modulate stability of the salt bridges) did not affect the rotational correlation time in the tandem further supporting independent rotational diffusion of two G domains. In a parallel line of experiments to detect and map weak self-association of the G domains, we analyzed NMR chemical shifts perturbations at a number of sites near the crystallographic dimer interface. The nearly complete lack of chemical shift perturbations in the tandem construct supported a simple model with the independent G domains repelled from each other by their overall negative charge. These results lead us to the conclusion that self-association of the G domains cannot be responsible for homodimerization of Ras reported in the literature. PMID:26331257

  3. Crystal form III of beta-cyclodextrin-ethanol inclusion complex: layer-type structure with dimeric motif.

    PubMed

    Aree, Thammarat; Chaichit, Narongsak

    2008-09-01

    The crystal form III of the beta-cyclodextrin (beta-CD)-ethanol inclusion complex [2(C(6)H(10)O(5))(7).1.5C(2)H(5)OH.19H(2)O] belongs to the triclinic space group P1 with unit cell constants: a=15.430(1), b=15.455(1), c=17.996(1)A, alpha=99.30(1) degrees , beta=113.18(1) degrees , gamma=103.04(1) degrees . beta-CD forms dimers comprising two identical monomers that adopt a 'round' conformation stabilized by intramolecular, interglucose O-3(n)cdots, three dots, centeredO-2(n+1) hydrogen bonds. The two beta-CD monomers of form III are isostructural to that of form I in the monoclinic space group P2(1) [Steiner, T.; Mason, S. A.; Saenger, W. J. Am. Chem. Soc.1991, 113, 5676-5687], but exhibit a striking difference from that of form II in the monoclinic space group C2 [Aree, T.; Chaichit, N. Carbohydr. Res.2003, 338, 1581-1589]. The small guest EtOH molecule orients differently in the large beta-CD cavity. In form III, two disordered EtOH molecules are embedded in the beta-CD-dimer cavity. A half occupied EtOH molecule (#1) is located above the O-4 plane of beta-CD #1, whereas another doubly disordered EtOH molecule (#2, #3) is situated at about the middle of the beta-CD-dimer cavity. The three EtOH sites are maintained in positions by making van der Waals contacts to each other and to the surrounding water sites and beta-CD O-3-H group. The EtOH molecules disordered (occupancy 0.3) above the beta-CD O-4 plane in form I and fully occupied beneath the O-4 plane in form II are strongly held in positions by hydrogen bonding with the surrounding water site and beta-CD O-6-H, O-3-H groups. Occurrence of the beta-CD dimer as a structural motif of channel-type packing (form II) and layer-type packing (form III) is attributed to the higher tendency for self aggregation under the moderate acidic conditions. At weak acidic conditions, beta-CD prefers a herringbone mode (form I). PMID:18490008

  4. A multinuclear copper(I) cluster forms the dimerization interface in copper-loaded human copper chaperone for superoxide dismutase.

    PubMed

    Stasser, Jay P; Siluvai, Gnana S; Barry, Amanda N; Blackburn, Ninian J

    2007-10-23

    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. PMID:17902702

  5. 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.

  6. Dimeric peptides with three different linkers self-assemble with phospholipids to form peptide nanodiscs that stabilize membrane proteins.

    PubMed

    Larsen, Andreas N; Sørensen, Kasper K; Johansen, Nicolai T; Martel, Anne; Kirkensgaard, Jacob J K; Jensen, Knud J; Arleth, Lise; Midtgaard, Søren Roi

    2016-07-01

    Three dimers of the amphipathic α-helical peptide 18A have been synthesized with different interhelical linkers inserted between the two copies of 18A. The dimeric peptides were denoted 'beltides' where Beltide-1 refers to the 18A-dimer without a linker, Beltide-2 is the 18A-dimer with proline (Pro) as a linker and Beltide-3 is the 18A-dimer linked by two glycines (Gly-Gly). The self-assembly of the beltides with the phospholipid DMPC was studied with and without the incorporated membrane protein bacteriorhodopsin (bR) through a combination of coarse-grained MD simulations, size-exclusion chromatography (SEC), circular dichroism (CD) spectroscopy, small-angle scattering (SAS), static light scattering (SLS) and UV-Vis spectroscopy. For all three beltides, MD and combined small-angle X-ray and -neutron scattering were consistent with a disc structure composed by a phospholipid bilayer surrounded by a belt of peptides and with a total disc diameter of approximately 10 nm. CD confirmed that all three beltides were α-helical in the free form and with DMPC. However, as shown by SEC the different interhelical linkers clearly led to different properties of the beltides. Beltide-3, with the Gly-Gly linker, was very adaptable such that peptide nanodiscs could be formed for a broad range of different peptide to lipid stoichiometries and therefore also possible disc-sizes. On the other hand, both Beltide-2 with the Pro linker and Beltide-1 without a linker were less adaptable and would only form discs of certain peptide to lipid stoichiometries. SLS revealed that the structural stability of the formed peptide nanodiscs was also highly affected by the linkers and it was found that Beltide-1 gave more stable discs than the other two beltides. With respect to membrane protein stabilization, each of the three beltides in combination with DMPC stabilizes the seven-helix transmembrane protein bacteriorhodopsin significantly better than the detergent octyl glucoside, but no

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

    PubMed

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

    2015-06-01

    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

  8. 18F-fluorodeoxyglucose positron emission tomography, aging, and apolipoprotein E genotype in cognitively normal persons

    PubMed Central

    Knopman, David S.; Jack, Clifford R.; Wiste, Heather J.; Lundt, Emily S.; Weigand, Stephen D.; Vemuri, Prashanthi; Lowe, Val J.; Kantarci, Kejal; Gunter, Jeffrey L.; Senjem, Matthew L.; Mielke, Michelle M.; Roberts, Rosebud O.; Boeve, Bradley F.; Petersen, Ronald C.

    2014-01-01

    Our objective was to examine associations between glucose metabolism, as measured by 18F-fluorodeoxyglucose positron emission tomography (FDG PET), and age and to evaluate the impact of carriage of an apolipoprotein E (APOE) ε4 allele on glucose metabolism and on the associations between glucose metabolism and age. We studied 806 cognitively normal (CN) and 70 amyloid-imaging-positive cognitively impaired participants (35 with mild cognitive impairment and 35 with Alzheimer’s disease [AD] dementia) from the Mayo Clinic Study of Aging, Mayo Alzheimer’s Disease Research Center and an ancillary study who had undergone structural MRI, FDG PET, and 11C-Pittsburgh compound B (PiB) PET. Using partial volume corrected and uncorrected FDG PET glucose uptake ratios, we evaluated associations of regional FDG ratios with age and carriage of an APOE ε4 allele in CN participants between the ages of 30 and 95 years, and compared those findings with the cognitively impaired participants. In region-of-interest (ROI) analyses, we found modest but statistically significant declines in FDG ratio in most cortical and subcortical regions as a function of age. We also found a main effect of APOE ε4 genotype on FDG ratio, with greater uptake in ε4 noncarriers compared with carriers but only in the posterior cingulate and/or precuneus, lateral parietal, and AD-signature meta-ROI. The latter consisted of voxels from posterior cingulate and/or precuneus, lateral parietal, and inferior temporal. In age- and sex-matched CN participants the magnitude of the difference in partial volume corrected FDG ratio in the AD-signature meta-ROI for APOE ε4 carriers compared with noncarriers was about 4 times smaller than the magnitude of the difference between age- and sex-matched elderly APOE ε4 carrier CN compared with AD dementia participants. In an analysis in participants older than 70 years (31.3% of whom had elevated PiB), there was no interaction between PiB status and APOE ε4 genotype

  9. Enhanced Diabetes Susceptibility in Community Dwelling Han Elders Carrying the Apolipoprotein E 3/3 Genotype

    PubMed Central

    Wang, Tao; Zhu, Min-jie; Wang, Jing-hua; Zhang, Zhen-lian; Wang, Zhe; Su, Ning; Liu, Yuan-yuan; Shi, Yan-chen; Xiao, Shi-fu; Li, Xia

    2016-01-01

    Despite Apolipoprotein E (ApoE) being one of the main apolipoproteins in the blood, the association between its genotype and the high cholesterol or blood glucose levels commonly seen in clinical practice is inconclusive. Such research is also lacking in the Han population. The aim of this study was to investigate the association between APOE genotype, diabetes, and plasma glucose and lipid levels. We included 243 community-dwelling elderly residents in this study. Participant APOE genotypes were assessed and were simultaneously tested for weight, height, blood glucose, triglycerides, cholesterol, and high- and low-density lipoprotein. In addition, gender, age, years of education, cognitive function, and medical history was recorded. Subjects were divided into 3 groups based on APOE genotype: APOE ε2 group (ε2/ε2 and ε2/ε3), APOE ε3 group (ε3/ε3), and APOE ε4 group (ε2/ε4, ε3/ε4 and ε4/ε4). Comparisons between groups were conducted for the incidence of diabetes, high blood pressure, and dementia, as well as for differences in body-mass index, fasting plasma glucose, and blood lipids. The APOE ε3/ε3 genotype exhibited the highest frequency (70.4%) among the subjects. Participants in the APOE ε3 group demonstrated significantly higher levels of fasting plasma glucose than those in the APOE ε2 and APOE ε4 groups (P<0.05). The APOE ε3 group had slightly higher abnormal fasting plasma glucose values than did the APOE ε2 group (P = 0.065). Furthermore, the APOE3 genotype was significantly correlated with both fasting plasma glucose level and glucose abnormality (P< 0.05) and trended toward statistically significant correlation with diabetes (P = 0.082). The correlation between APOE2 and low low-density lipoprotein levels also approached statistical significance (P = 0.052). Thus, elderly community dwelling residents of Han ethnicity carrying the APOE ε3/ε3 genotype might have higher plasma glucose levels and a higher occurrence of diabetes. PMID

  10. 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

  11. Human Apolipoprotein E Isoforms differentially affect Bone Mass and Turnover in vivo

    PubMed Central

    Dieckmann, Marco; Beil, F. Timo; Mueller, Brigitte; Bartelt, Alexander; Marshall, Robert P.; Koehne, Till; Amling, Michael; Ruether, Wolfgang; Cooper, Jackie A.; Humphries, Steve E.; Herz, Joachim; Niemeier, Andreas

    2012-01-01

    The primary role of apolipoprotein E (apoE) is to mediate the cellular uptake of lipoproteins. However, a new role for apoE as a regulator of bone metabolism in mice has recently been established. In contrast to mice, the human APOE gene is characterized by three common isoforms APOE ε2, ε3 and ε4 that result in different metabolic properties of the apoE isoforms, but it remains controversial whether the APOE polymorphism influences bone traits in humans. To clarify this, we investigated bone phenotypes of apoE knock-in mice, which express one human isoform each (apoE2 k.i., apoE3 k.i., apoE4 k.i.) in place of the mouse apoE. Analysis of 12 week-old female knock-in mice revealed increased levels of biochemical bone formation and resorption markers in apoE2 k.i. animals as compared to apoE3 k.i. and apoE4 k.i., with a reduced OPG/RANKL ratio in apoE2 k.i., indicating increased turnover with prevailing resorption in apoE2 k.i.. Accordingly, histomorphometric and μCT analyses demonstrated significantly lower trabecular bone mass in apoE2 than in apoE3 and apoE4 k.i. animals, which was reflected by a significant reduction of lumbar vertebrae maximum force resistance. Unlike trabecular bone, femoral cortical thickness, and stability was not differentially affected by the apoE isoforms. To extend these observations to the human situation, plasma from middle-aged healthy men homozygous for ε2/ε2, ε3/ε3, and ε4/ε4 (n=21, n=80, n=55 respectively) was analyzed with regard to bone turnover markers. In analogy to apoE2 k.i. mice, a lower OPG/RANKL ratio was observed in the serum of ε2/ε2 carriers as compared to ε3/ε3 and ε4/ε4 individuals (p=0.02 for ε2/ε2 vs ε4/ε4). In conclusion, the current data strongly underline the general importance of apoE as a regulator of bone metabolism and identifies the APOE ε2 allele as a potential genetic risk factor for low trabecular bone mass and vertebral fractures in humans. PMID:22991192

  12. A Complete Backbone Assignment of the Apolipoprotein E LDL Receptor Binding Domain [Letter to the Editor

    SciTech Connect

    Xu, Chao; Sivashanmugam, Arun; Hoyt, David W.; Wang, Jianjun

    2005-06-01

    Human apolipoprotein E (apoE) is a 299-residue exchangeable apolipoprotein that was initially recognized as a major determinant in lipoprotein metabolism and cardiovascular diseases. Recent evidence has indicated that apoE also plays critical roles in several other important biological processes not directly related to its lipid transport function, including Alzheimer's disease, cognitive function, immunoregulation, cell signaling, and possibly even infectious diseases. ApoE contains two structural/functional domains: A N-terminal domain spanning residues 1-191 that is responsible for apoE's LDL receptor binding activity and a C-terminal domain (residues 216-199) that is responsible for lipoprotein-binding (1). The x-ray crystal structure of the lipid-free apoE N-terminal domain was solved by Wilson et al in 1991 which represented the only high-resolution structure of this protein. This structure showed an unusually elongated four-helix bundle (2) that was organized in such 2 a way that its hydrophobic faces were directed towards the protein interior, whereas the hydrophilic faces were oriented towards the solvent. The major receptor-binding region, residues 130-150, was located on the fourth helix. The amphipathic a-helices were connected by short loops, giving rise to a compact, globular structure. However, this structure only contained residues 23-165. Recent studies have shown that residues beyond residues 23-165 are also very important to the apoE LDL receptor binding activity. For example, a mutation at position R172 reduces the receptor binding activity of apoE to only {approx}2% (3). In addition, an E3K mutant significantly increased the apoE receptor binding activity as well (4). While the x-ray crystal structure of the apoE N-terminal domain provided detailed structural information for most region of this domain, this structure does not provide an explanation of the above experimental results regarding the structural contribution to apoE's LDL receptor

  13. 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

  14. Apolipoprotein E isotype-dependent modulation of microRNA-146a in plasma and brain.

    PubMed

    Teter, Bruce; LaDu, Mary Jo; Sullivan, Patrick M; Frautschy, Sally A; Cole, Greg M

    2016-08-01

    The Apolipoprotein E (ApoE) isotype ApoE4 is a prevalent genetic risk factor for Alzheimer's disease (AD) that can modulate systemic and central inflammation, independent of amyloid accumulation. Although disruption of innate immune toll receptor signaling is modulated by ApoE and observed in AD, ApoE isotype-specific effects remain poorly understood. Therefore, we examined the effect of the ApoE isotype on the brain levels of major regulators of TLR signaling including miR146a, a microRNA enriched in the brain. We used 6-month-old ApoE3 or ApoE4 targeted replacement mice with and without mutant familial AD transgenes. ApoE4 reduced the levels of miR146a compared with ApoE3, both in the brain (29%; P<0.0001) and in plasma (47%; P<0.05), which correlated with each other (r=0.74; P<0.05). The presence of 5xFAD transgenes increased brain miR146a in both ApoE3 (E3FAD) and ApoE4 (E4FAD) mice; however, miR146a levels in E4FAD mice remained lower than those in E3FAD mice (62%; P<0.05), despite increased amyloid and inflammation. Supporting these observations, ApoE4 brains showed increased expression of interleukin receptor-associated kinase-1 (160%; P<0.05) (normally downregulated by miR146) that correlated inversely with miR146a levels (r=0.637; P<0.0001). Reduced negative feedback of toll-like receptor signaling (by miRNA146a) can explain early-life hypersensitivity to innate immune stimuli (including Aβ) in ApoE4 carriers. Thus, ApoE4 causes early dysregulation of a central controller of the innate immune system both centrally and systemically. This defect persists with familial AD pathology and may be relevant to ApoE4 AD risk. PMID:27281274

  15. Biophysical Analysis of Apolipoprotein E3 Variants Linked with Development of Type III Hyperlipoproteinemia

    PubMed Central

    Georgiadou, Dimitra; Chroni, Angeliki; Vezeridis, Alexander; Zannis, Vassilis I.; Stratikos, Efstratios

    2011-01-01

    Background Apolipoprotein E (apoE) is a major protein of the lipoprotein transport system that plays important roles in lipid homeostasis and protection from atherosclerosis. ApoE is characterized by structural plasticity and thermodynamic instability and can undergo significant structural rearrangements as part of its biological function. Mutations in the 136–150 region of the N-terminal domain of apoE, reduce its low density lipoprotein (LDL) receptor binding capacity and have been linked with lipoprotein disorders, such as type III hyperlipoproteinemia (HLP) in humans. However, the LDL-receptor binding defects for these apoE variants do not correlate well with the severity of dyslipidemia, indicating that these variants may carry additional properties that contribute to their pathogenic potential. Methodology/Principal Findings In this study we examined whether three type III HLP predisposing apoE3 variants, namely R136S, R145C and K146E affect the biophysical properties of the protein. Circular dichroism (CD) spectroscopy revealed that these mutations do not significantly alter the secondary structure of the protein. Thermal and chemical unfolding analysis revealed small thermodynamic alterations in each variant compared to wild-type apoE3, as well as effects in the reversibility of the unfolding transition. All variants were able to remodel multillamelar 1,2-Dimyristoyl-sn-glycero-3-phosphocholine (DMPC) vesicles, but R136S and R145C had reduced kinetics. Dynamic light scattering analysis indicated that the variant R136S exists in a higher-order oligomerization state in solution. Finally, 1-anilinonaphthalene-8-sulfonic acid (ANS) binding suggested that the variant R145C exposes a larger amount of hydrophobic surface to the solvent. Conclusions/Significance Overall, our findings suggest that single amino acid changes in the functionally important region 136–150 of apoE3 can affect the molecule's stability and conformation in solution and may underlie

  16. Identification of a Chrysanthemic Ester as an Apolipoprotein E Inducer in Astrocytes.

    PubMed

    Fan, Jianjia; Zareyan, Shahab; 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; Kulic, Iva

    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

  17. Enhanced Diabetes Susceptibility in Community Dwelling Han Elders Carrying the Apolipoprotein E 3/3 Genotype.

    PubMed

    Ban, Chun-Xia; Zhong, Li; Wang, Tao; Zhu, Min-Jie; Wang, Jing-Hua; Zhang, Zhen-Lian; Wang, Zhe; Su, Ning; Liu, Yuan-Yuan; Shi, Yan-Chen; Xiao, Shi-Fu; Li, Xia

    2016-01-01

    Despite Apolipoprotein E (ApoE) being one of the main apolipoproteins in the blood, the association between its genotype and the high cholesterol or blood glucose levels commonly seen in clinical practice is inconclusive. Such research is also lacking in the Han population. The aim of this study was to investigate the association between APOE genotype, diabetes, and plasma glucose and lipid levels. We included 243 community-dwelling elderly residents in this study. Participant APOE genotypes were assessed and were simultaneously tested for weight, height, blood glucose, triglycerides, cholesterol, and high- and low-density lipoprotein. In addition, gender, age, years of education, cognitive function, and medical history was recorded. Subjects were divided into 3 groups based on APOE genotype: APOE ε2 group (ε2/ε2 and ε2/ε3), APOE ε3 group (ε3/ε3), and APOE ε4 group (ε2/ε4, ε3/ε4 and ε4/ε4). Comparisons between groups were conducted for the incidence of diabetes, high blood pressure, and dementia, as well as for differences in body-mass index, fasting plasma glucose, and blood lipids. The APOE ε3/ε3 genotype exhibited the highest frequency (70.4%) among the subjects. Participants in the APOE ε3 group demonstrated significantly higher levels of fasting plasma glucose than those in the APOE ε2 and APOE ε4 groups (P<0.05). The APOE ε3 group had slightly higher abnormal fasting plasma glucose values than did the APOE ε2 group (P = 0.065). Furthermore, the APOE3 genotype was significantly correlated with both fasting plasma glucose level and glucose abnormality (P< 0.05) and trended toward statistically significant correlation with diabetes (P = 0.082). The correlation between APOE2 and low low-density lipoprotein levels also approached statistical significance (P = 0.052). Thus, elderly community dwelling residents of Han ethnicity carrying the APOE ε3/ε3 genotype might have higher plasma glucose levels and a higher occurrence of diabetes. PMID

  18. Cognitive Deficits and Disruption of Neurogenesis in a Mouse Model of Apolipoprotein E4 Domain Interaction*

    PubMed Central

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

    2014-01-01

    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. PMID:24324264

  19. Effects of Apolipoprotein E Genotype on Blood Cholesterol in Adolescent Girls

    PubMed Central

    Fulton, Janet E.; Dai, Shifan; Grunbaum, Jo Anne; Boerwinkle, Eric; Labarthe, Darwin R.

    2015-01-01

    Background Few investigations have examined whether associations between the apolipoprotein E genotype (apo E) and total cholesterol or LDL-C are modified or explained by other characteristics. The objective of this study was to explore effects of behavioral characteristics, physical growth, body composition, sexual maturation, and endocrine function on age trajectories of total cholesterol and LDL-C by apo E in adolescent girls. Methods Participants were 247 Caucasian adolescent girls followed for 4 years. Apo E genotyping and plasma lipid concentrations were determined from fasting blood samples using standard enzymatic methods. Age; gender; fat-free mass (FFM); BMI; percent body fat (PBF); sexual maturation (pubic hair, Tanner Stages 1–5); estradiol concentration (EST); energy intake; and physical activity were collected or calculated with standard methods. Results In models including the proposed explanatory variables, apo E genotype remained strongly associated with total cholesterol and LDL-C. Girls with the epsilon (ε)3/3 and ε3/4 genotypes (where ε is the protein isoform of the apo E gene), relative to those with ε2/3, had total cholesterol and LDL-C values 16–23 mg/dL higher throughout adolescence. Age–apo E interaction terms remained significant. FFM, BMI, PBF, pubic-hair stage, and EST showed a significant effect on total cholesterol and LDL-C. When the combination of pubic-hair stage, EST, and one of FFM, BMI, and PBF was included in total cholesterol or LDL-C models, only EST was significant. Conclusions Adolescent girls with ε3/3 and ε3/4 genotypes had higher total cholesterol and LDL-C and showed different patterns of change, compared to those with ε2/3 genotype. These apo E effects were independent of behavioral characteristics, physical growth, body composition, sexual maturation, and endocrine function. Girls with ε3/3 or ε3/4 genotypes may be at risk for elevated total cholesterol and LDL-C later in life. PMID:19524160

  20. Prevalence of the apolipoprotein E Arg145Cys dyslipidemia at-risk polymorphism in African-derived populations.

    PubMed

    Abou Ziki, Maen D; Strulovici-Barel, Yael; Hackett, Neil R; Rodriguez-Flores, Juan L; Mezey, Jason G; Salit, Jacqueline; Radisch, Sharon; Hollmann, Charleen; Chouchane, Lotfi; Malek, Joel; Zirie, Mahmoud A; Jayyuosi, Amin; Gotto, Antonio M; Crystal, Ronald G

    2014-01-15

    Apolipoprotein E, a protein component of blood lipid particles, plays an important role in lipid transport. Different mutations in the apolipoprotein E gene have been associated with various clinical phenotypes. In an initiated study of Qataris, we observed that 17% of the African-derived genetic subgroup were heterozygotes for a rare Arg145Cys (R145C) variant that functions as a dominant trait with incomplete penetrance associated with type III hyperlipoproteinemia. On the basis of this observation, we hypothesized that the R145C polymorphism might be common in African-derived populations. The prevalence of the R145C variant was assessed worldwide in the "1000 Genomes Project" and in 1,012 whites and 1,226 African-Americans in New York, New York. The 1000 Genomes Project data demonstrated that the R145C polymorphism is rare in non-African-derived populations but present in 5% to 12% of Sub-Saharan African-derived populations. The R145C polymorphism was also rare in New York whites (1 of 1,012, 0.1%); however, strikingly, 53 of the 1,226 New York African-Americans (4.3%) were R145C heterozygotes. The lipid profiles of the Qatari and New York R145C heterozygotes were compared with those of controls. The Qatari R145C subjects had higher triglyceride levels than the Qatari controls (p <0.007) and the New York African-American R145C subjects had an average of 52% greater fasting triglyceride levels than the New York African-American controls (p <0.002). From these observations, likely millions of people worldwide derived from Sub-Saharan Africans are apolipoprotein E R145C. In conclusion, although larger epidemiologic studies are necessary to determine the long-term consequences of this polymorphism, the available evidence suggests it is a common cause of a mild triglyceride dyslipidemia. PMID:24239320

  1. Dimeric Ube2g2 simultaneously engages donor and acceptor ubiquitins to form Lys48-linked ubiquitin chains

    PubMed Central

    Liu, Weixiao; Shang, Yongliang; Zeng, Yan; Liu, Chao; Li, Yanchang; Zhai, Linhui; Wang, Pan; Lou, Jizhong; Xu, Ping; Ye, Yihong; Li, Wei

    2014-01-01

    Cellular adaptation to proteotoxic stress at the endoplasmic reticulum (ER) depends on Lys48-linked polyubiquitination by ER-associated ubiquitin ligases (E3s) and subsequent elimination of ubiquitinated retrotranslocation products by the proteasome. The ER-associated E3 gp78 ubiquitinates misfolded proteins by transferring preformed Lys48-linked ubiquitin chains from the cognate E2 Ube2g2 to substrates. Here we demonstrate that Ube2g2 synthesizes linkage specific ubiquitin chains by forming an unprecedented homodimer: The dimerization of Ube2g2, mediated primarily by electrostatic interactions between two Ube2g2s, is also facilitated by the charged ubiquitin molecules. Mutagenesis studies show that Ube2g2 dimerization is required for ER-associated degradation (ERAD). In addition to E2 dimerization, we show that a highly conserved arginine residue in the donor Ube2g2 senses the presence of an aspartate in the acceptor ubiquitin to position only Lys48 of ubiquitin in proximity to the donor E2 active site. These results reveal an unanticipated mode of E2 self-association that allows the E2 to effectively engage two ubiquitins to specifically synthesize Lys48-linked ubiquitin chains. PMID:24366945

  2. Hsp70 Forms Antiparallel Dimers Stabilized by Post-translational Modifications to Position Clients for Transfer to Hsp90

    PubMed Central

    Morgner, Nina; Schmidt, Carla; Beilsten-Edmands, Victoria; Ebong, Ima-obong; Patel, Nisha A.; Clerico, Eugenia M.; Kirschke, Elaine; Daturpalli, Soumya; Jackson, Sophie E.; Agard, David; Robinson, Carol V.

    2015-01-01

    Summary Protein folding in cells is regulated by networks of chaperones, including the heat shock protein 70 (Hsp70) system, which consists of the Hsp40 cochaperone and a nucleotide exchange factor. Hsp40 mediates complex formation between Hsp70 and client proteins prior to interaction with Hsp90. We used mass spectrometry (MS) to monitor assemblies formed between eukaryotic Hsp90/Hsp70/Hsp40, Hop, p23, and a client protein, a fragment of the glucocorticoid receptor (GR). We found that Hsp40 promotes interactions between the client and Hsp70, and facilitates dimerization of monomeric Hsp70. This dimerization is antiparallel, stabilized by post-translational modifications (PTMs), and maintained in the stable heterohexameric client-loading complex Hsp902Hsp702HopGR identified here. Addition of p23 to this client-loading complex induces transfer of GR onto Hsp90 and leads to expulsion of Hop and Hsp70. Based on these results, we propose that Hsp70 antiparallel dimerization, stabilized by PTMs, positions the client for transfer from Hsp70 to Hsp90. PMID:25921532

  3. Identification of an amino-terminal fragment of apolipoprotein E4 that localizes to neurofibrillary tangles of the Alzheimer's disease brain.

    PubMed

    Rohn, Troy T; Catlin, Lindsey W; Coonse, Kendra G; Habig, Jeffrey W

    2012-09-26

    Although the risk factor for harboring the apolipoprotein E4 (apoE4) allele in late-onset Alzheimer's disease (AD) is well known, the mechanism by which apoE4 contributes to AD pathogenesis has yet to be clarified. Preferential cleavage of the ApoE4 isoform relative to other polymorphic forms appears to be significant, as the resulting fragments are associated with hallmarks of AD. To examine the possible role of apoE4 proteolysis in AD, we designed a site-directed antibody directed at position D172, which would yield a predicted amino-terminal fragment previously identified in AD brain extracts. Western blot analysis utilizing this novel antibody, termed the amino-terminal apoE4 cleavage fragment (nApoE4CF) Ab, consistently identified the predicted amino-terminal fragment (∼18kDa) in several commercially available forms of human recombinant apoE4 purified from E. coli. Mass spectrometry confirmed the identity of this 18kDa fragment as being an amino-terminal fragment of apoE4. Immunohistochemical experiments indicated the nApoE4CF Ab specifically labeled neurofibrillary tangles (NFTs) in AD frontal cortex sections that colocalized with the mature tangle marker PHF-1. Taken together, these results suggest a novel cleavage event of apoE4, generating an amino-terminal fragment that localizes within NFTs of the AD brain. PMID:22902767

  4. 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

  5. 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.

  6. Perforin and Granzyme B Have Separate and Distinct Roles during Atherosclerotic Plaque Development in Apolipoprotein E Knockout Mice

    PubMed Central

    Hiebert, Paul R.; Boivin, Wendy A.; Zhao, Hongyan; McManus, Bruce M.; Granville, David J.

    2013-01-01

    The granzyme B/perforincytotoxic pathway is a well established mechanism of initiating target cell apoptosis. Previous studies have suggested a role for the granzyme B/perforin cytotoxic pathway in vulnerable atherosclerotic plaque formation. In the present study, granzyme B deficiency resulted in reduced atherosclerotic plaque development in the descending aortas of apolipoprotein E knockout mice fed a high fat diet for 30 weeks while perforindeficiency resulted in greater reduction in plaque development with significantly less plaque area than granzyme Bdeficient mice. In contrast to the descending aorta, no significant change in plaque size was observed in aortic roots from either granzyme Bdeficient or perforindeficient apolipoprotein E knockout mice. However, atherosclerotic plaques in the aortic roots did exhibit significantly more collagen in granzyme B, but not perforin deficient mice. Together these results suggest significant, yet separate roles for granzyme B and perforin in the pathogenesis of atherosclerosis that go beyond the traditional apoptotic pathway with additional implications in plaque development, stability and remodelling of extracellular matrix. PMID:24205352

  7. 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. PMID:26547561

  8. The dimer formed by the periplasmic domain of EpsL from the Type 2 Secretion System of Vibrio parahaemolyticus

    PubMed Central

    Abendroth, Jan; Kreger, Allison C.; Hol, Wim G. J.

    2010-01-01

    The Type 2 Secretion System (T2SS), occurring in many Gram-negative bacteria, is responsible for the transport of a diversity of proteins from the periplasm across the outer membrane into the extracellular space. In Vibrio cholerae, the T2SS secretes several unrelated proteins including the major virulence factor cholera toxin. The T2SS consists of three subassemblies, one of which is the Inner Membrane Complex which contains multiple copies of five proteins, including the bitopic membrane protein EpsL. Here we report the 2.3 Å resolution crystal structure of the periplasmic domain of EpsL (peri-EpsL) from V. parahaemolyticus, which is 56 % identical in sequence to its homolog in V. cholerae. The domain adopts a circular permutation of the “common” ferredoxin fold with two contiguous sub-domains. Remarkably, this permutation has so far only been observed once before: in the periplasmic domain of EpsM (peri-EpsM), another T2SS protein which interacts with EpsL. These two domains are 18 % identical in sequence which may indicate a common evolutionary origin. Both peri-EpsL and peri-EpsM form dimers, but the organization of the subunits in these dimers appears to be entirely different. We have previously shown that the cytoplasmic domain of EpsL is also dimeric and forms a heterotetramer with the first domain of the “secretion ATPase” EpsE. The latter enzyme is most likely hexameric. The possible consequences of the combination of the different symmetries of EpsE and EpsL for the architecture of the T2SS are discussed. PMID:19646531

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

    PubMed Central

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

    2008-01-01

    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 ∼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 ∼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. PMID:18276648

  10. Re-examination of the dimerization state of leucine-rich repeat kinase 2: predominance of the monomeric form.

    PubMed

    Ito, Genta; Iwatsubo, Takeshi

    2012-02-01

    Mutations in the LRRK2 (leucine-rich repeat kinase 2) gene have been identified in PARK8, a major form of autosomal-dominantly inherited familial Parkinson's disease, although the biochemical properties of LRRK2 are not fully understood. It has been proposed that LRRK2 predominantly exists as a homodimer on the basis of the observation that LRRK2, with a theoretical molecular mass of 280 kDa, migrates at 600 kDa (p600 LRRK2) on native polyacrylamide gels. In the present study, we biochemically re-examined the nature of p600 LRRK2 and found that p600 LRRK2 was fractionated with a single peak at ~272 kDa by ultracentrifugation on a glycerol gradient. In addition, p600 LRRK2 behaved similarly to monomeric proteins upon two-dimensional electrophoretic separation. These results suggested a monomeric composition of p600 LRRK2 within cells. The p600 LRRK2 exhibited kinase activity as well as GTP-binding activity, and forced dimerization of LRRK2 neither upregulated its kinase activity nor altered its subcellular localization. Collectively, we conclude that the monomer form of LRRK2 is predominant within cells, and that dimerization is dispensable for its enzymatic activity. PMID:22047502

  11. Megabirnavirus structure reveals a putative 120-subunit capsid formed by asymmetrical dimers with distinctive large protrusions.

    PubMed

    Miyazaki, Naoyuki; Salaipeth, Lakha; Kanematsu, Satoko; Iwasaki, Kenji; Suzuki, Nobuhiro

    2015-08-01

    Rosellinia necatrix megabirnavirus 1 (RnMBV1) W779 is a bi-segmented dsRNA virus and a strain of the type species Rosellinia necatrix megabirnavirus 1 of the family Megabirnaviridae. RnMBV1 causes severe reduction of both mycelial growth of Rosellinia necatrix in synthetic medium and fungal virulence to plant hosts, and thus has strong potential for virocontrol (biological control using viruses) of white rot. The structure of RnMBV1 was examined by cryo-electron microscopy and three-dimensional reconstruction at 15.7 Å resolution. The diameter of the RnMBV1 capsid was 520 Å, and the capsid was composed of 60 asymmetrical dimers in the T = 1 (so-called T = 2) lattice that is well conserved among dsRNA viruses. However, RnMBV1 has putatively 120 large protrusions with a width of ∼ 45 Å and a height of ∼ 50 Å on the virus surface, making it distinguishable from the other dsRNA viruses. PMID:25968130

  12. Anti-Inflammatory and Anti-Thrombotic Effects of the Fungal Metabolite Galiellalactone in Apolipoprotein E-Deficient Mice

    PubMed Central

    Schmidtke, Lisa; Schrick, Katharina; Reinhardt, Christoph; Jurk, Kerstin; Wu, Zhixiong; Xia, Ning; Li, Huige; Erkel, Gerhard; Walter, Ulrich; Kleinert, Hartmut; Pautz, Andrea

    2015-01-01

    Patients suffering from chronic inflammatory diseases have an increased mortality risk resulting from cardiovascular disorders due to enhanced atherosclerotic and thrombotic events. Until now, it is not completely understood in which way an abnormal expression of pro-inflammatory mediators contributes to this elevated cardiovascular risk, but there is a need for new drugs that on the one hand suppress the expression of pro-inflammatory mediators and on the other hand inhibit arterial platelet adhesion. Thus, we analyzed the anti-inflammatory and anti-thrombotic capacity of the fungal metabolite Galiellalactone in atherosclerosis-prone apolipoprotein E-deficient mice. Treatment of the mice with Galiellalactone lowered the inflammatory expression profile and improved blood clotting times, as well as platelet adhesion to the injured common carotid artery. The results indicate that administration of Galiellalactone is able to reduce the extent of inflammation and arterial platelet adhesion in this mouse model. PMID:26076475

  13. 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.

  14. 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.

  15. Anti-Inflammatory and Anti-Thrombotic Effects of the Fungal Metabolite Galiellalactone in Apolipoprotein E-Deficient Mice.

    PubMed

    Bollmann, Franziska; Jäckel, Sven; Schmidtke, Lisa; Schrick, Katharina; Reinhardt, Christoph; Jurk, Kerstin; Wu, Zhixiong; Xia, Ning; Li, Huige; Erkel, Gerhard; Walter, Ulrich; Kleinert, Hartmut; Pautz, Andrea

    2015-01-01

    Patients suffering from chronic inflammatory diseases have an increased mortality risk resulting from cardiovascular disorders due to enhanced atherosclerotic and thrombotic events. Until now, it is not completely understood in which way an abnormal expression of pro-inflammatory mediators contributes to this elevated cardiovascular risk, but there is a need for new drugs that on the one hand suppress the expression of pro-inflammatory mediators and on the other hand inhibit arterial platelet adhesion. Thus, we analyzed the anti-inflammatory and anti-thrombotic capacity of the fungal metabolite Galiellalactone in atherosclerosis-prone apolipoprotein E-deficient mice. Treatment of the mice with Galiellalactone lowered the inflammatory expression profile and improved blood clotting times, as well as platelet adhesion to the injured common carotid artery. The results indicate that administration of Galiellalactone is able to reduce the extent of inflammation and arterial platelet adhesion in this mouse model. PMID:26076475

  16. 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

    2016-03-01

    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. PMID:26795031

  17. 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.

  18. Role of apolipoprotein E4 in protecting children against early childhood diarrhea outcomes and implications for later development

    PubMed Central

    Oriá, Reinaldo B.; Patrick, Peter D.; Blackman, James A.; Lima, Aldo A.M.; Guerrant, Richard L.

    2014-01-01

    Summary Our group and others have reported a series of studies showing that heavy burdens of diarrheal diseases in the formative first two years of life in children in urban shantytowns have profound consequences of impaired physical and cognitive development lasting into later childhood and schooling. Based on these previous studies showing that apolipoprotein E4 (APOE4) is relatively common in favela children, we review recent data suggesting a protective role for the APOE4 allele in the cognitive and physical development of children with heavy burdens of diarrhea in early childhood. Despite being a marker for cognitive decline with Alzheimer's and cardiovascular diseases later in life, APOE4 appears to be important for cognitive development under the stress of heavy diarrhea. The reviewed findings provide a potential explanation for the survival advantage in evolution of the thrifty APOE4 allele and raise questions about its implications for human development under life-style changes and environmental challenges. PMID:17098371

  19. 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.

  20. 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

  1. 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. PMID:25919366

  2. Bax monomers form dimer units in the membrane that further self-assemble into multiple oligomeric species

    PubMed Central

    Subburaj, Yamunadevi; Cosentino, Katia; Axmann, Markus; Pedrueza-Villalmanzo, Esteban; Hermann, Eduard; Bleicken, Stephanie; Spatz, Joachim; García-Sáez, Ana J.

    2015-01-01

    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. PMID:26271728

  3. Apolipoprotein E polymorphisms and postprandial triglyceridemia before and after fenofibrate treatment in the Genetics of Lipid Lowering and Diet Network (GOLDN) Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  4. 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.…

  5. The Influence of the Epsilon4 Allele of the Apolipoprotein E Gene on Childhood IQ, Nonverbal Reasoning in Old Age, and Lifetime Cognitive Change.

    ERIC Educational Resources Information Center

    Deary, Ian J.; Whalley, Lawrence J.; St. Clair, David; Breen, Gerome; Leaper, Steve; Lemmon, Helen; Hayward, Caroline; Starr, John M.

    2003-01-01

    Examines the influence of apolipoprotein E gene states on three cognitive outcomes in 173 people at age 11 and in the same people at age 77 and examined the change in IQ between these ages. There was no significant main effect of gene status on IQ in youth or old age, nor in cognitive change across the lifespan. (SLD)

  6. Dietary Soy Protein Isolate Ameliorates Atherosclerotic Lesions in Apolipoprotein E-Deficient Mice Potentially by Inhibiting Monocyte Chemoattractant Protein-1 Expression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  7. 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.

  8. A nontransgenic mouse model shows inducible amyloid-β (Aβ) peptide deposition and elucidates the role of apolipoprotein E in the amyloid cascade

    PubMed Central

    Dolev, Iftach; Michaelson, Daniel M.

    2004-01-01

    The amyloid-β (Aβ) peptide, a major pathological hallmark of Alzheimer's disease (AD), undergoes a cascade of interactions resulting in the formation of soluble aggregates and their conversion in the brain to insoluble deposits and mature senile plaques. Furthermore, the apoE4 isoform of apolipoprotein E (apoE), which is the major genetic risk factor of AD, is associated with increased Aβ deposition. It is not known how the different Aβ aggregates in the amyloid cascade are formed, contribute to the pathogenesis of AD, or are affected by apoE4. To investigate the initial aggregation stages underlying the amyloid cascade in vivo and how apoE affects them, we examined the effects of prolonged inhibition and subsequent reactivation of the Aβ-degrading protease neprilysin on deposition, disaggregation, and fibrillization of Aβ in apoE-transgenic and control mice. In control mice, intracerebroventricular infusion of thiorphan, which inhibits neprilysin, induced Aβ42 and Aβ40 deposition and fibrillization. On termination of thiorphan treatment, the number of Aβ deposits decreased, whereas the fibrillar Aβ deposits were unaffected. Similar treatments in apoE-deficient mice and mice transgenic for human apoE4 or apoE3 revealed that apoE4 enhances specifically the nucleation and aggregation of immunopositive Aβ deposits and that reversible disaggregation of these deposits and their irreversible conversion to fibrillar deposits are stimulated similarly by the different apoE isoforms. Deposition of Aβ and its enhancement by apoE4 were accompanied by increased astrogliosis both far from and near the Aβ deposits, suggesting that astrogliosis might be triggered by both insoluble and soluble Aβ aggregates. PMID:15365176

  9. 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. PMID:25395590

  10. The putative K+ channel subunit AtKCO3 forms stable dimers in Arabidopsis

    PubMed Central

    Rocchetti, Alessandra; Sharma, Tripti; Wulfetange, Camilla; Scholz-Starke, Joachim; Grippa, Alexandra; Carpaneto, Armando; Dreyer, Ingo; Vitale, Alessandro; Czempinski, Katrin; Pedrazzini, Emanuela

    2012-01-01

    The permeation pore of K+ channels is formed by four copies of the pore domain. AtKCO3 is the only putative voltage-independent K+ channel subunit of Arabidopsis thaliana with a single pore domain. KCO3-like proteins recently emerged in evolution and, to date, have been found only in the genus Arabidopsis (A. thaliana and A. lyrata). We show that the absence of KCO3 does not cause marked changes in growth under various conditions. Only under osmotic stress we observed reduced root growth of the kco3-1 null-allele line. This phenotype was complemented by expressing a KCO3 mutant with an inactive pore, indicating that the function of KCO3 under osmotic stress does not depend on its direct ability to transport ions. Constitutively overexpressed AtKCO3 or AtKCO3::GFP are efficiently sorted to the tonoplast indicating that the protein is approved by the endoplasmic reticulum quality control. However, vacuoles isolated from transgenic plants do not have significant alterations in current density. Consistently, both AtKCO3 and AtKCO3::GFP are detected as homodimers upon velocity gradient centrifugation, an assembly state that would not allow for activity. We conclude that if AtKCO3 ever functions as a K+ channel, active tetramers are held by particularly weak interactions, are formed only in unknown specific conditions and may require partner proteins. PMID:23162563

  11. 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

  12. 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.

  13. Evolution of magnetization due to asymmetric dimerization: theoretical considerations and application to aberrant oligomers formed by apoSOD1(2SH).

    PubMed

    Sekhar, Ashok; Bain, Alex D; Rumfeldt, Jessica A O; Meiering, Elizabeth M; Kay, Lewis E

    2016-02-17

    A set of coupled differential equations is presented describing the evolution of magnetization due to an exchange reaction whereby a pair of identical monomers form an asymmetric dimer. In their most general form the equations describe a three-site exchange process that reduces to two-site exchange under certain limiting conditions that are discussed. An application to the study of sparsely populated, transiently formed sets of aberrant dimers, symmetric and asymmetric, of superoxide dismutase is presented. Fits of concentration dependent CPMG relaxation dispersion profiles provide measures of the dimer dissociation constants and both on- and off-rates. Dissociation constants on the order of 70 mM are extracted from fits of the data, with dimeric populations of ∼2% and lifetimes of ∼6 and ∼2 ms for the symmetric and asymmetric complexes, respectively. This work emphasizes the important role that NMR relaxation experiments can play in characterizing very weak molecular complexes that remain invisible to most biophysical approaches. PMID:26156673

  14. Succinyl-5-aminoimidazole-4-carboxamide-1-ribose 5'-Phosphate (SAICAR) Activates Pyruvate Kinase Isoform M2 (PKM2) in Its Dimeric Form.

    PubMed

    Yan, Ming; Chakravarthy, Srinivas; Tokuda, Joshua M; Pollack, Lois; Bowman, Gregory D; Lee, Young-Sam

    2016-08-23

    Human pyruvate kinase isoform M2 (PKM2) is a glycolytic enzyme isoform implicated in cancer. Malignant cancer cells have higher levels of dimeric PKM2, which is regarded as an inactive form of tetrameric pyruvate kinase. This perceived inactivity has fueled controversy about how the dimeric form of pyruvate kinase might contribute to cancer. Here we investigate enzymatic properties of PKM2(G415R), a variant derived from a cancer patient, which we show by size-exclusion chromatography and small-angle X-ray scattering to be a dimer that cannot form a tetramer in solution. Although PKM2(G415R) binds to fructose 1,6-bisphosphate (FBP), unlike the wild type this PKM2 variant shows no activation by FBP. In contrast, PKM2(G415R) is activated by succinyl-5-aminoimidazole-4-carboxamide-1-ribose 5'-phosphate (SAICAR), an endogenous metabolite that we previously showed correlates with an increased level of cell proliferation and promotes protein kinase activity of PKM2. Our results demonstrate an important and unexpected enzymatic activity of the PKM2 dimer that likely has a key role in cancer progression. PMID:27481063

  15. 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. PMID:25261526

  16. Inhalation exposure of gas-metal arc stainless steel welding fume increased atherosclerotic lesions in apolipoprotein E knockout mice.

    PubMed

    Erdely, Aaron; Hulderman, Tracy; Salmen-Muniz, Rebecca; Liston, Angie; Zeidler-Erdely, Patti C; Chen, Bean T; Stone, Samuel; Frazer, David G; Antonini, James M; Simeonova, Petia P

    2011-07-01

    Epidemiological studies suggest that welding, a process which generates an aerosol of inhalable gases and metal rich particulates, increases the risk for cardiovascular disease. In this study we analyzed systemic inflammation and atherosclerotic lesions following gas metal arc-stainless steel (GMA-SS) welding fume exposure. Apolipoprotein E knockout (apoE(-/-)) mice, fed a Western diet, were exposed to GMA-SS at 40mg/m(3) for 3h/day for ten days (∼8.26μg daily alveolar deposition). Mice were sacrificed two weeks after exposure and serum chemistry, serum protein profiling and aortic lesion area were determined. There were no significant changes in serum total cholesterol, triglycerides or alanine aminotransferase. Serum levels of uric acid, a potent antioxidant, were decreased perhaps suggesting a reduced capacity to combat systemic oxidative stress. Inflammatory serum proteins interleukin 1 beta (IL-1β) and monocyte chemoattractant protein 3 (MCP-3) were increased two weeks after GMA-SS exposure. Analysis of atherosclerotic plaques showed an increase in lesion area as the result of GMA-SS exposure. In conclusion, GMA-SS exposure showed evidence of systemic inflammation and increased plaque progression in apoE(-/-) mice. These results complement epidemiological and functional human studies that suggest welding may result in adverse cardiovascular effects. PMID:21513782

  17. Apolipoprotein E ϵ4 is positively related to spatial performance but unrelated to hippocampal volume in healthy young adults.

    PubMed

    Stening, Eva; Persson, Jonas; Eriksson, Elias; Wahlund, Lars-Olof; Zetterberg, Henrik; Söderlund, Hedvig

    2016-02-15

    The apolipoprotein E (APOE) ϵ4 allele is known to be a major genetic risk factor for Alzheimer's disease (AD). It has been linked to especially episodic memory decline and hippocampal atrophy in both healthy and demented elderly populations. In young adults, ϵ4 carriers have shown better performance in episodic memory compared to non-carriers. Spatial memory, however, has not been thoroughly assessed in relation to APOE in spite of its dependence on the hippocampus. In this study, we assessed the effect of APOE genotype on a variety of spatial and episodic memory tasks as well as hippocampal volume assessed through manual tracing in a sample of young adults (N=123). We also assessed whether potential effects were modulated by sex. The presence of one or more ϵ4 alleles had positive effects on spatial function and memory and object location memory, but no effect on word recognition. Men were superior to women in spatial function and memory but there were no sex differences in the other tasks. In spite of APOE ϵ4 carriers having superior performance in several memory tasks, no difference was found as a function of APOE genotype in hippocampal volume. To our knowledge, this study is the first to show that APOE ϵ4 has a positive effect on spatial ability in young adults. PMID:26581118

  18. Identification, expression and function of apolipoprotein E in annual fish Nothobranchius guentheri: implication for an aging marker.

    PubMed

    Wang, Xia; Shang, Xiaomei; Luan, Jing; Zhang, Shicui

    2014-06-01

    Apolipoprotein E (apoE) is a lipid-associated protein present in both plasma and in central nervous system. Variation in apoE gene has been reported to be associated with longevity in humans as well as with aged diseases such as atherosclerosis, Alzheimer's disease, and Parkinson's disease. However, information regarding the function and structure-activity relationship of apoE in lower vertebrates is rather limited. In this study we show that the apoE gene from the annual fish Nothobranchius guentheri, NapoE, encodes a protein of 262 amino acids, which shares common structural features characteristic of mammalian apoE. We also show that like human apoE, recombinant NapoE is able to inhibit LDL oxidation, and it is the N-terminal domain of NapoE with lysine or arginine residues that plays a key role in inhibition of LDL oxidation. NapoE is predominantly expressed in the liver of N. guentheri, consistent with that in mammalian species. More importantly, we demonstrate an age-dependent down-regulation of NapoE gene, rendering it a suitable biomarker of aging. This lays a foundation for further study of the role of apoE in the aging process of fish. PMID:24573419

  19. 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.

  20. Targeted Intracellular Delivery of Resveratrol to Glioblastoma Cells Using Apolipoprotein E-Containing Reconstituted HDL as a Nanovehicle

    PubMed Central

    Kim, Sea H.; Adhikari, Birendra Babu; Cruz, Siobanth; Schramm, Michael P.; Vinson, Joe A.; Narayanaswami, Vasanthy

    2015-01-01

    The objective of this study is to transport and deliver resveratrol to intracellular sites using apolipoprotein E3 (apoE3). Reconstituted high-density lipoprotein (rHDL) bearing resveratrol (rHDL/res) was prepared using phospholipids and the low-density lipoprotein receptor (LDLr)-binding domain of apoE3. Biophysical characterization revealed that resveratrol was partitioned into the phospholipid bilayer of discoidal rHDL/res particles (~19 nm diameter). Co-immunoprecipitation studies indicated that the LDLr-binding ability of apoE3 was retained. Cellular uptake of resveratrol to intracellular sites was evaluated in glioblastoma A-172 cells by direct fluorescence using chemically synthesized NBD-labeled resveratrol (res/NBD) embedded in rHDL/res. Competition and inhibition studies indicate that the uptake is by receptor mediated endocytosis via the LDLr, with co-localization of apoE3 and res/NBD in late endosomes/lysosomes. We propose that rHDL provides an ideal hydrophobic milieu to sequester resveratrol and that rHDL containing apoE3 serves as an effective “nanovehicle” to transport and deliver resveratrol to targeted intracellular sites. PMID:26258481

  1. The thromboxane receptor antagonist S18886 attenuates renal oxidant stress and proteinuria in diabetic apolipoprotein E-deficient mice.

    PubMed

    Xu, Shanqin; Jiang, Bingbing; Maitland, Karlene A; Bayat, Hossein; Gu, Jiali; Nadler, Jerry L; Corda, Stefano; Lavielle, Gilbert; Verbeuren, Tony J; Zuccollo, Adriana; Cohen, Richard A

    2006-01-01

    Arachidonic acid metabolites, some of which may activate thromboxane A(2) receptors (TPr) and contribute to the development of diabetes complications, including nephropathy, are elevated in diabetes. This study determined the effect of blocking TPr with S18886 or inhibiting cyclooxygenase with aspirin on oxidative stress and the early stages of nephropathy in streptozotocin-induced diabetic apolipoprotein E(-/-) mice. Diabetic mice were treated with S18886 (5 mg . kg(-1) . day(-1)) or aspirin (30 mg . kg(-1) . day(-1)) for 6 weeks. Neither S18886 nor aspirin affected hyperglycemia or hypercholesterolemia. There was intense immunohistochemical staining for nitrotyrosine in diabetic mouse kidney. In addition, a decrease in manganese superoxide dismutase (MnSOD) activity was associated with an increase in MnSOD tyrosine-34 nitration. Tyrosine nitration was significantly reduced by S18886 but not by aspirin. Staining for the NADPH oxidase subunit p47(phox), inducible nitric oxide synthase, and 12-lipoxygenase was increased in diabetic mouse kidney, as were urine levels of 12-hydroxyeicosatetraenoic acid and 8-iso-prostaglandin F(2alpha). S18886 attenuated all of these markers of oxidant stress and inflammation. Furthermore, S18886 significantly attenuated microalbuminuria in diabetic mice and ameliorated histological evidence of diabetic nephropathy, including transforming growth factor-beta and extracellular matrix expression. Thus, in contrast to inhibiting cyclooxygenase, blockade of TPr may have therapeutic potential in diabetic nephropathy, in part by attenuating oxidative stress. PMID:16380483

  2. 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

  3. Pharmacogenetics of apolipoprotein E gene during lipid-lowering therapy: lipid levels and prevention of coronary heart disease.

    PubMed

    Nieminen, Tuomo; Kähönen, Mika; Viiri, Leena E; Grönroos, Paula; Lehtimäki, Terho

    2008-10-01

    A non-optimal plasma concentration of lipids is among the major modifiable risk factors of atherosclerosis. Therefore, the prevention of cardiovascular disease by means of lipid-lowering therapy with statins and other agents is of great importance for patient groups where a lifestyle change, for example, diet modification, does not lead to adequately reduced lipid levels. The response of low-density-lipoprotein cholesterol (LDL-C) levels to statin therapy is highly variable. This is partly attributed to hereditary variation in genes involved in pharmacokinetics, pharmacodynamics and lipid metabolism. The pharmacogenetics of lipid-lowering therapy have been investigated for more than 40 different genes. The gene for apolipoprotein E (APOE) has been the most frequently studied, particularly regarding the epsilon2/epsilon3/epsilon4 polymorphism. Those with the epsilon4 allele seem to have the poorest and those with the epsilon2 allele the strongest response to statins with regards to LDL-C levels. In addition, the epsilon2 carriers may reach the LDL-C treatment goals more frequently than epsilon4 carriers. Few studies have investigated the interaction of the APOE epsilon2/epsilon3/epsilon4 polymorphism and lipid-lowering therapy in relation to the course of coronary heart disease; the results are contradictory and so far inconclusive. This review summarizes the pharmacogenetic findings related to the influence of APOE gene variation on lipid responses and the prevention of coronary heart disease during lipid-lowering therapy. PMID:18855536

  4. 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

  5. Pitavastatin Reduces Inflammation in Atherosclerotic Plaques in Apolipoprotein E-Deficient Mice with Late Stage Renal Disease

    PubMed Central

    Figueiredo, Jose-Luiz; New, Sophie E. P.; Quillard, Thibaut; Goettsch, Claudia; Koga, Jun-ichiro; Sonoki, Hiroyuki; Matsumoto, Jiro; Aikawa, Masanori; Aikawa, Elena

    2015-01-01

    Objectives Chronic renal disease (CRD) accelerates atherosclerosis and cardiovascular calcification. Statins reduce low-density lipoprotein-cholesterol levels in patients with CRD, however, the benefits of statins on cardiovascular disease in CRD remain unclear. This study has determined the effects of pitavastatin, the newest statin, on arterial inflammation and calcification in atherogenic mice with CRD. Methods and Results CRD was induced by 5/6 nephrectomy in cholesterol-fed apolipoprotein E-deficient mice. Mice were randomized into three groups: control mice, CRD mice, and CRD mice treated with pitavastatin. Ultrasonography showed that pitavastatin treatment significantly attenuated luminal stenosis in brachiocephalic arteries of CRD mice. Near-infrared molecular imaging and correlative Mac3 immunostaining demonstrated a significant reduction in macrophage accumulation in pitavastatin-treated CRD mice. Pitavastatin treatment reduced levels of osteopontin in plasma and atherosclerotic lesions in CRD mice, but did not produce a significant reduction in calcification in atherosclerotic plaques as assesses by histology. CRD mice had significantly higher levels of phosphate in plasma than did control mice, which did not change by pitavastatin. In vitro, pitavastatin suppressed the expression of osteopontin in peritoneal macrophages stimulated with phosphate or calcium/phosphate in concentrations similar to those found in human patients with CRD. Conclusion Our study provides in vivo evidence that pitavastatin reduces inflammation within atherosclerotic lesions in CRD mice. PMID:26367531

  6. 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

  7. Apolipoprotein E ε4 Allele was Associated With Nonlesional Mesial Temporal Lobe Epilepsy in Han Chinese Population

    PubMed Central

    Li, Zhimei; Ding, Chengyun; Gong, Xiping; Wang, Xiaofei; Cui, Tao

    2016-01-01

    Abstract Apolipoprotein E (APOE) gene has been implicated as one of the genes susceptible to temporal lobe epilepsy (TLE), but the association is inconsistent. We carried out a study to investigate the association of APOEε4 allele with a subtype of TLE-nonlesional mesial temporal lobe epilepsy (NLMTLE) in Han Chinese people. The study consisted of total 308 NLMTLE patients and 302 controls in Han Chinese. The APOE polymorphisms were genotyped using polymerase chain reaction (PCR) DNA sequencing. We compared the frequency of APOEε4 allele and carrying status between NLMTLE patients and control subjects to test for the association of APOEε4 allele with NLMTLE clinical status. Carrying status of APOEε4 allele was significantly associated with the risk of NLMTLE. No effect of APOEε4 allele was found on the age of onset, duration of epilepsy, or frequency of seizure. Moreover, there was no association between APOEε4 allele and hippocampal sclerosis (HS) or febrile convulsion (FC) history. Our study provided an evidence that APOEε4 allele was a possible risk factor for NLMTLE, and further study with a larger sample is needed to warrant this finding. PMID:26945380

  8. 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

  9. Apolipoprotein E polymorphism and acute ischemic stroke: a diffusion- and perfusion-weighted magnetic resonance imaging study.

    PubMed

    Liu, Yawu; Laakso, Mikko P; Karonen, Jari O; Vanninen, Ritva L; Nuutinen, Juho; Soimakallio, Seppo; Aronen, Hannu J

    2002-11-01

    Diffusion- and perfusion-weighted magnetic resonance imaging (MRI) was used to study the putative effects of apolipoprotein E (ApoE) polymorphism in stroke. Thirty-one patients with acute stroke, comparative for age and gender were scanned, nine of whom were ApoE allele epsilon 4 carriers. Initially, less than 24 hours from the onset of stroke, the epsilon 4 carriers had significantly smaller volumes of hypoperfusion on relative cerebral blood volume map (P = 0.001), and smaller infarct volumes (P = 0.008) compared with the noncarriers. By day 8, this difference in the infarct volumes had disappeared, suggesting relatively enhanced infarct growth. On average, the total infarct volume increased 145% of the initial infarct volume in the epsilon 4 carriers, and 84% in the noncarriers. There were strong correlations between the imaging findings and clinical status initially and with the outcome 3 months after the stroke in the epsilon 4 noncarriers, but, with a single exception at acute phase, a lack thereof in the epsilon 4 carriers. These patterns were virtually similar in a subgroup of patients with middle cerebral artery stroke. These data support the hypothesis of increased general vulnerability of the brain in the epsilon 4 carriers. Thus, the effects of ApoE polymorphism should be accounted for when interpreting diffusion- and perfusion-weighted MRI studies, particularly if predicting lesion growth. PMID:12439291

  10. 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