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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. Apolipoprotein E4 effects in Alzheimer's disease are mediated by synaptotoxic oligomeric amyloid-β.

    PubMed

    Koffie, Robert M; Hashimoto, Tadafumi; Tai, Hwan-Ching; Kay, Kevin R; Serrano-Pozo, Alberto; Joyner, Daniel; Hou, Steven; Kopeikina, Katherine J; Frosch, Matthew P; Lee, Virginia M; Holtzman, David M; Hyman, Bradley T; Spires-Jones, Tara L

    2012-07-01

    The apolipoprotein E ε4 gene is the most important genetic risk factor for sporadic Alzheimer's disease, but the link between this gene and neurodegeneration remains unclear. Using array tomography, we analysed >50000 synapses in brains of 11 patients with Alzheimer's disease and five non-demented control subjects and found that synapse loss around senile plaques in Alzheimer's disease correlates with the burden of oligomeric amyloid-β in the neuropil and that this synaptotoxic oligomerized peptide is present at a subset of synapses. Further analysis reveals apolipoprotein E ε4 patients with Alzheimer's disease have significantly higher oligomeric amyloid-β burden and exacerbated synapse loss around plaques compared with apolipoprotein E ε3 patients. Apolipoprotein E4 protein colocalizes with oligomeric amyloid-β and enhances synaptic localization of oligomeric amyloid-β by >5-fold. Biochemical characterization shows that the amyloid-β enriched at synapses by apolipoprotein E4 includes sodium dodecyl sulphate-stable dimers and trimers. In mouse primary neuronal culture, lipidated apolipoprotein E4 enhances oligomeric amyloid-β association with synapses via a mechanism involving apolipoprotein E receptors. Together, these data suggest that apolipoprotein E4 is a co-factor that enhances the toxicity of oligomeric amyloid-β both by increasing its levels and directing it to synapses, providing a link between apolipoprotein E ε4 genotype and synapse loss, a major correlate of cognitive decline in Alzheimer's disease.

  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. Apolipoprotein E receptors: linking brain development and Alzheimer's disease.

    PubMed

    Herz, J; Beffert, U

    2000-10-01

    Alzheimer's disease is a debilitating neurodegenerative disorder that afflicts an increasing part of our ageing population. An isoform of apolipoprotein E, a protein that mediates the transport of lipids and cholesterol in the circulatory system, predisposes carriers of this allele to the common late-onset form of the disease. How this protein is related to a neurodegenerative disorder is an enigma. Mounting evidence indicates that apolipoprotein E receptors, which are abundantly expressed in most neurons in the central nervous system, also fulfill critical functions during brain development and may profoundly influence the pathogenesis of Alzheimer's disease.

  5. Apolipoprotein E Isoforms and AMD.

    PubMed

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

    2016-01-01

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

  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. Direct Transcriptional Effects of Apolipoprotein E.

    PubMed

    Theendakara, Veena; Peters-Libeu, Clare A; Spilman, Patricia; Poksay, Karen S; Bredesen, Dale E; Rao, Rammohan V

    2016-01-20

    A major unanswered question in biology and medicine is the mechanism by which the product of the apolipoprotein E ε4 allele, the lipid-binding protein apolipoprotein E4 (ApoE4), plays a pivotal role in processes as disparate as Alzheimer's disease (AD; in which it is the single most important genetic risk factor), atherosclerotic cardiovascular disease, Lewy body dementia, hominid evolution, and inflammation. Using a combination of neural cell lines, skin fibroblasts from AD patients, and ApoE targeted replacement mouse brains, we show in the present report that ApoE4 undergoes nuclear translocation, binds double-stranded DNA with high affinity (low nanomolar), and functions as a transcription factor. Using chromatin immunoprecipitation and high-throughput DNA sequencing, our results indicate that the ApoE4 DNA binding sites include ∼1700 gene promoter regions. The genes associated with these promoters provide new insight into the mechanism by which AD risk is conferred by ApoE4, because they include genes associated with trophic support, programmed cell death, microtubule disassembly, synaptic function, aging, and insulin resistance, all processes that have been implicated in AD pathogenesis. Significance statement: This study shows for the first time that apolipoprotein E4 binds DNA with high affinity and that its binding sites include 1700 promoter regions that include genes associated with neurotrophins, programmed cell death, synaptic function, sirtuins and aging, and insulin resistance, all processes that have been implicated in Alzheimer's disease pathogenesis.

  9. Apolipoprotein E, especially apolipoprotein E4, increases the oligomerization of amyloid β peptide.

    PubMed

    Hashimoto, Tadafumi; Serrano-Pozo, Alberto; Hori, Yukiko; Adams, Kenneth W; Takeda, Shuko; Banerji, Adrian Olaf; Mitani, Akinori; Joyner, Daniel; Thyssen, Diana H; Bacskai, Brian J; Frosch, Matthew P; Spires-Jones, Tara L; Finn, Mary Beth; Holtzman, David M; Hyman, Bradley T

    2012-10-24

    Alzheimer's disease (AD) is the most common progressive neurodegenerative disorder causing dementia. Massive deposition of amyloid β peptide (Aβ) as senile plaques in the brain is the pathological hallmark of AD, but oligomeric, soluble forms of Aβ have been implicated as the synaptotoxic component. The apolipoprotein E ε 4 (apoE ε4) allele is known to be a genetic risk factor for developing AD. However, it is still unknown how apoE impacts the process of Aβ oligomerization. Here, we found that the level of Aβ oligomers in APOE ε4/ε4 AD patient brains is 2.7 times higher than those in APOE ε3/ε3 AD patient brains, matched for total plaque burden, suggesting that apoE4 impacts the metabolism of Aβ oligomers. To test this hypothesis, we examined the effect of apoE on Aβ oligomer formation. Using both synthetic Aβ and a split-luciferase method for monitoring Aβ oligomers, we observed that apoE increased the level of Aβ oligomers in an isoform-dependent manner (E2 < E3 < E4). This effect appears to be dependent on the ApoE C-terminal domain. Moreover, these results were confirmed using endogenous apoE isolated from the TBS-soluble fraction of human brain, which increased the formation of Aβ oligomers. Together, these data show that lipidated apoE, especially apoE4, increases Aβ oligomers in the brain. Higher levels of Aβ oligomers in the brains of APOE ε4/ε4 carriers compared with APOE ε3/ε3 carriers may increase the loss of dendritic spines and accelerate memory impairments, leading to earlier cognitive decline in AD.

  10. 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.

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

    PubMed

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

    2016-05-30

    We propose an optical dimer formed from two spherical lenses bound by the pressure that light exerts on matter. With the help of the method of force tracing, we find the required graded-index profiles of the lenses for the existence of the dimer. We study the dynamics of the opto-mechanical interaction of lenses under the illumination of collimated light beams and quantitatively validate the performance of proposed dimer. We also examine the stability of dimer due to the lateral misalignments and we show how restoring forces bring the dimer into lateral equilibrium. The dimer can be employed in various practical applications such as optical manipulation, sensing and imaging. PMID:27410066

  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 genotype in diverse neurodegenerative disorders.

    PubMed

    Schneider, J A; Gearing, M; Robbins, R S; de l'Aune, W; Mirra, S S

    1995-07-01

    While the apolipoprotein E (ApoE) epsilon 4 allele is a recognized risk factor for Alzheimer's disease (AD), an association of epsilon 4 with other neurodegenerative diseases (NDs) has not been extensively explored. We examined 51 cases of neuropathologically confirmed ND. After eliminating 18 cases exhibiting pathology sufficient to warrant an additional diagnosis of AD, three disorders characterized by tau-related cytoskeletal pathology, i.e., Pick's disease, corticobasal degeneration, and progressive supra-nuclear palsy, showed increased epsilon 4 frequencies. Since the number of cases within each category was small, these increased epsilon 4 frequencies were not statistically significant. beta-Amyloid (beta A4) immunoreactive diffuse plaques were observed in many of these cases. While we cannot eliminate the possibility that these patients were destined to develop AD, these changes may merely reflect an independent association of epsilon 4 with amyloid deposition. These preliminary data affirm the need for further study of well-characterized cases to explore the relationship of ApoE to cytoskeletal pathology and ND. PMID:7611717

  14. 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.

  15. Human IgG2 can form covalent dimers.

    PubMed

    Yoo, Esther M; Wims, Letitia A; Chan, Lisa A; Morrison, Sherie L

    2003-03-15

    Unlike IgA and IgM, IgG has not yet been shown to form covalent polymers. However in the presence of specific Ag, murine IgG3 has been shown to polymerize through noncovalent interactions. In contrast to the noncovalent oligomers found with murine IgG3, we have detected covalent dimers in three different recombinant human IgG2 Abs produced in myeloma cells. Both IgG2,kappa and IgG2,lambda can form dimers. In addition, analysis of pooled human gamma globulin and several normal sera revealed the presence of IgG2 dimers. The IgG2 dimers are in contrast to the noncovalent IgG dimers found in pooled sera of multiple donors resulting from idiotype/anti-idiotype (Id/anti-Id) interactions. Cyanogen bromide cleavage analysis suggests that one or more Cys residues in the gamma 2 hinge are involved in dimer assembly. The potential role of IgG2 dimers in immunity against carbohydrate Ags is discussed.

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

    PubMed

    Choy, Nicole; Raussens, Vincent; Narayanaswami, Vasanthy

    2003-11-28

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

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

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

    2016-01-01

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

  20. 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

  1. Impact of apolipoprotein E on Alzheimer's disease.

    PubMed

    Hauser, Paul S; Ryan, Robert O

    2013-10-01

    A key feature of Alzheimer's disease (AD) is deposition of extracellular amyloid plaque comprised chiefly of the amyloid β (Aβ) peptide. Studies of Aβ have shown that it may be catabolized by proteolysis or cleared from brain via members of the low-density lipoprotein receptor family. Alternatively, Aβ can undergo a conformational transition from α-helix to β-sheet, a conformer that displays a propensity to self-associate, oligomerize and form fibrils. Furthermore, β- sheet conformers catalyze conversion of other α-helical Aβ peptides to β-sheet, feeding the oligomer and fibril assembly process. A factor that influences the fate of Aβ in the extracellular space is apolipoprotein (apo) E. Polymorphism at position 112 or 158 in apoE give rise to three major isoforms. One isoform in particular, apoE4 (Arg at 112 and 158), has generated considerable interest since the discovery that it is the major genetic risk factor for development of late onset AD. Despite this striking correlation, the molecular mechanism underlying apoE4's association with AD remains unclear. A tertiary structural feature distinguishing apoE4 from apoE2 and apoE3, termed domain interaction, is postulated to affect the conformation and orientation of its' two independently folded domains. This feature has the potential to influence apoE4's interaction with Aβ, its sensitivity to proteolysis or its lipid accrual and receptor binding activities. Thus, domain interaction may constitute the principal molecular feature of apoE4 that predisposes carriers to late onset AD. By understanding the contribution of apoE4 to AD at the molecular level new therapeutic or prevention strategies will emerge.

  2. Dimers of mitochondrial ATP synthase form the permeability transition pore

    PubMed Central

    Giorgio, Valentina; von Stockum, Sophia; Antoniel, Manuela; Fabbro, Astrid; Fogolari, Federico; Forte, Michael; Glick, Gary D.; Petronilli, Valeria; Zoratti, Mario; Szabó, Ildikó; Lippe, Giovanna; Bernardi, Paolo

    2013-01-01

    Here we define the molecular nature of the mitochondrial permeability transition pore (PTP), a key effector of cell death. The PTP is regulated by matrix cyclophilin D (CyPD), which also binds the lateral stalk of the FOF1 ATP synthase. We show that CyPD binds the oligomycin sensitivity-conferring protein subunit of the enzyme at the same site as the ATP synthase inhibitor benzodiazepine 423 (Bz-423), that Bz-423 sensitizes the PTP to Ca2+ like CyPD itself, and that decreasing oligomycin sensitivity-conferring protein expression by RNAi increases the sensitivity of the PTP to Ca2+. Purified dimers of the ATP synthase, which did not contain voltage-dependent anion channel or adenine nucleotide translocator, were reconstituted into lipid bilayers. In the presence of Ca2+, addition of Bz-423 triggered opening of a channel with currents that were typical of the mitochondrial megachannel, which is the PTP electrophysiological equivalent. Channel openings were inhibited by the ATP synthase inhibitor AMP-PNP (γ-imino ATP, a nonhydrolyzable ATP analog) and Mg2+/ADP. These results indicate that the PTP forms from dimers of the ATP synthase. PMID:23530243

  3. Apolipoprotein E and alpha1-antichymotrypsin polymorphism in Alzheimer's disease.

    PubMed

    Nacmias, B; Tedde, A; Latorraca, S; Piacentini, S; Bracco, L; Amaducci, L; Guarnieri, B M; Petruzzi, C; Ortenzi, L; Sorbi, S

    1996-10-01

    A recent observation has shown that a common polymorphism in the alpha1-antichymotrypsin (ACT) gene modifies the apolipoprotein E (ApoE) epsilon4-associated Alzheimer's disease (AD) risk identifying the combination of the ACT/AA and ApoE epsilon4/epsilon4 genotypes as a potential susceptibility marker for AD. We analyzed the segregation of the ApoE and ACT polymorphism in sporadic and familial AD patients. In none of the sporadic AD patients did we find the combination of the ACT/AA and ApoE epsilon4/epsilon4 genotypes. The frequency of ApoE epsilon4/epsilon4 homozygosity in the AD sample resulted highest for the ACT/ TT genotype (17.6%). Our data fail to confirm any additional association with AD beyond the ApoE epsilon4 allele with any ACT genotype, suggesting that ACT does not represent an additional risk factor for AD. PMID:8871590

  4. No implication of apolipoprotein E polymorphism in Italian schizophrenic patients.

    PubMed

    Sorbi, S; Nacmias, B; Tedde, A; Latorraca, S; Forleo, P; Guarnieri, B M; Petruzzi, C; Daneluzzo, E; Ortenzi, L; Piacentini, S; Amaducci, L

    1998-03-13

    Numerous studies have provided evidence for a genetic association of the Apolipoprotein E (ApoE) epsilon4 allele and late onset familial and sporadic Alzheimer's disease (AD). Clinical observations show that a proportion of schizophrenic patients may suffer from severe cognitive impairment. That could reflect a particular clinical aspect of this mental disorder or a common, yet unknown, neurodegenerative mechanism. We analysed the ApoE gene polymorphism in a sample of 69 Italian patients with schizophrenia, 140 AD patients and 121 controls. In schizophrenic patients, the distribution of ApoE genotypes does not significantly differ from that of controls. No effect of the ApoE genotype on age of onset was found. The frequency of ApoE alleles in Italian schizophrenic patients is comparable with control values, suggesting that ApoE polymorphism does not represent a risk factor for schizophrenia. PMID:9572600

  5. 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

  6. 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.

  7. Apolipoprotein E polymorphism in hemodialysed patients and healthy controls

    PubMed Central

    Hubacek, Jaroslav A.; Bloudickova, Silvie; Kubinova, Ruzena; Pikhart, Hynek; Viklicky, Ondrej; Bobak, Martin

    2014-01-01

    The possible association between the end-stage renal disease (ESRD) and apolipoprotein E (APOE) polymorphism was found in some, but not all studies. We have analysed the APOE genotypes in 995 haemodialysed patients (cases) and a sample of 6242 healthy individuals (controls) in the Czech Republic. There was a statistically significant difference in the frequencies of APOE alleles between the cases and controls, with more carriers of the APOE2 allele in ESRD patients (15.9%) than in controls (12.2%) (p=0.005). The odds ratio of ESRD for the APOE2 allele, compared with APOE3E3 homozygotes, was 1.37 (95% confidence interval 1.13-1.67). The strength of the association increased with the time spent on haemodialysis: the odds ratios of all-cause ESRD in patients dialysed for 8 or more years, 1-8 years and less than one year (non-survivors) were 1.27 (0.94-1.71), 1.41 (1.09-1.81) and 1.94 (0.88-4.18), respectively. This study suggests that the APOE2 allele is a possible genetic risk factor for all-cause ESRD in Caucasians. PMID:19565203

  8. 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

  9. Role of Apolipoprotein E in β-Amyloidogenesis

    PubMed Central

    Hori, Yukiko; Hashimoto, Tadafumi; Nomoto, Hidetoshi; Hyman, Bradley T.; Iwatsubo, Takeshi

    2015-01-01

    Human APOE ϵ4 allele is a strong genetic risk factor of Alzheimer disease. Neuropathological and genetic studies suggested that apolipoprotein E4 (apoE4) protein facilitates deposition of amyloid β peptide (Aβ) in the brain, although the mechanism whereby apoE4 increases amyloid aggregates remains elusive. Here we show that injection of Aβ protofibrils induced Aβ deposition in the brain of APP transgenic mice, suggesting that Aβ protofibrils acted as a seed for aggregation and deposition of Aβ in vivo. Injection of Aβ protofibrils together with apoE3 significantly attenuated Aβ deposition, whereas apoE4 did not have this effect. In vitro assays revealed that the conversion of Aβ protofibrils to fibrils progressed more slowly upon coincubation with apoE2 or apoE3 compared with that with apoE4. Aβ protofibrils complexed with apoE4 were less stable than those with apoE2 or apoE3. These data suggest that the suppression effect of apoE2 or apoE3 on the structural conversion of Aβ protofibrils to fibrils is stronger than those of apoE4, thereby impeding β-amyloid deposition. PMID:25918154

  10. Absence of apolipoprotein E protects mice from cerebral malaria.

    PubMed

    Kassa, Fikregabrail Aberra; Van Den Ham, Kristin; Rainone, Anthony; Fournier, Sylvie; Boilard, Eric; Olivier, Martin

    2016-01-01

    Cerebral malaria claims the life of millions of people each year, particularly those of children, and is a major global public health problem. Thus, the identification of novel malaria biomarkers that could be utilized as diagnostic or therapeutic targets is becoming increasingly important. Using a proteomic approach, we previously identified unique biomarkers in the sera of malaria-infected individuals, including apolipoprotein E (ApoE). ApoE is the dominant apolipoprotein in the brain and has been implicated in several neurological disorders; therefore, we were interested in the potential role of ApoE in cerebral malaria. Here we report the first demonstration that cerebral malaria is markedly attenuated in ApoE(-/-) mice. The protection provided by the absence of ApoE was associated with decreased sequestration of parasites and T cells within the brain, and was determined to be independent from the involvement of ApoE receptors and from the altered lipid metabolism associated with the knock-out mice. Importantly, we demonstrated that treatment of mice with the ApoE antagonist heparin octasaccharide significantly decreased the incidence of cerebral malaria. Overall, our study indicates that the reduction of ApoE could be utilized in the development of therapeutic treatments aimed at mitigating the neuropathology of cerebral malaria. PMID:27647324

  11. Apolipoprotein e: essential catalyst of the Alzheimer amyloid cascade.

    PubMed

    Potter, Huntington; Wisniewski, Thomas

    2012-01-01

    The amyloid cascade hypothesis remains a robust model of AD neurodegeneration. However, amyloid deposits contain proteins besides Aβ, such as apolipoprotein E (apoE). Inheritance of the apoE4 allele is the strongest genetic risk factor for late-onset AD. However, there is no consensus on how different apoE isotypes contribute to AD pathogenesis. It has been hypothesized that apoE and apoE4 in particular is an amyloid catalyst or "pathological chaperone". Alternatively it has been posited that apoE regulates Aβ clearance, with apoE4 been worse at this function compared to apoE3. These views seem fundamentally opposed. The former would indicate that removing apoE will reduce AD pathology, while the latter suggests increasing brain ApoE levels may be beneficial. Here we consider the scientific basis of these different models of apoE function and suggest that these seemingly opposing views can be reconciled. The optimal therapeutic target may be to inhibit the interaction of apoE with Aβ rather than altering apoE levels. Such an approach will not have detrimental effects on the many beneficial roles apoE plays in neurobiology. Furthermore, other Aβ binding proteins, including ACT and apo J can inhibit or promote Aβ oligomerization/polymerization depending on conditions and might be manipulated to effect AD treatment.

  12. Absence of apolipoprotein E protects mice from cerebral malaria

    PubMed Central

    Kassa, Fikregabrail Aberra; Van Den Ham, Kristin; Rainone, Anthony; Fournier, Sylvie; Boilard, Eric; Olivier, Martin

    2016-01-01

    Cerebral malaria claims the life of millions of people each year, particularly those of children, and is a major global public health problem. Thus, the identification of novel malaria biomarkers that could be utilized as diagnostic or therapeutic targets is becoming increasingly important. Using a proteomic approach, we previously identified unique biomarkers in the sera of malaria-infected individuals, including apolipoprotein E (ApoE). ApoE is the dominant apolipoprotein in the brain and has been implicated in several neurological disorders; therefore, we were interested in the potential role of ApoE in cerebral malaria. Here we report the first demonstration that cerebral malaria is markedly attenuated in ApoE−/− mice. The protection provided by the absence of ApoE was associated with decreased sequestration of parasites and T cells within the brain, and was determined to be independent from the involvement of ApoE receptors and from the altered lipid metabolism associated with the knock-out mice. Importantly, we demonstrated that treatment of mice with the ApoE antagonist heparin octasaccharide significantly decreased the incidence of cerebral malaria. Overall, our study indicates that the reduction of ApoE could be utilized in the development of therapeutic treatments aimed at mitigating the neuropathology of cerebral malaria. PMID:27647324

  13. 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

  14. Transgenic Drosophila model to study apolipoprotein E4-induced neurodegeneration.

    PubMed

    Haddadi, Mohammad; Nongthomba, Upendra; Jahromi, Samaneh Reiszadeh; Ramesh, S R

    2016-03-15

    The ε4 isoform of apolipoprotein E (ApoE4) that is involved in neuron-glial lipid metabolism has been demonstrated as the main genetic risk factor in late-onset of Alzheimer's disease. However, the mechanism underlying ApoE4-mediated neurodegeneration remains unclear. We created a transgenic model of neurodegenerative disorder by expressing ε3 and ε4 isoforms of human ApoE in the Drosophila melanogaster. The genetic models exhibited progressive neurodegeneration, shortened lifespan and memory impairment. Genetic interaction studies between amyloid precursor protein and ApoE in axon pathology of the disease revealed that over expression of hApoE in Appl-expressing neurons of Drosophila brain causes neurodegeneration. Moreover, acute oxidative damage in the hApoE transgenic flies triggered a neuroprotective response of hApoE3 while chronic induction of oxidative damage accelerated the rate of neurodegeneration. This Drosophila model may facilitate analysis of the molecular and cellular events implicated in hApoE4 neurotoxicity.

  15. 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

  16. Apolipoprotein E and Alzheimer's disease: the implications of progress in molecular medicine.

    PubMed

    Mayeux, R; Schupf, N

    1995-09-01

    We review the current status as well as the risks and benefits of a recently developed DNA test of risk for Alzheimer's disease: the apolipoprotein E genotype. While apolipoprotein E genotypes may indicate a degree of susceptibility, the gene is neither necessary nor sufficient to cause the disease; thus, many questions remain. Because risk prediction is not straightforward, practical issues related to the testing of complex diseases like Alzheimer's and to the ethical, legal, and social implications of genetic tests require careful consideration and unambiguous answers. The use of apolipoprotein E genotyping in patients with Alzheimer's disease should be limited to research centers, and additional studies are strongly recommended. Apolipoprotein E genotypes should not be available to third parties such as insurers or employers until genotypic risks are fully understood. National policies that encourage scientific investigation while maintaining individual privacy and limiting unnecessary access to genetic information should be immediately developed.

  17. 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.

  18. Apolipoprotein E and Alzheimer's disease. A role in amyloid catabolism.

    PubMed

    Poirier, J

    2000-01-01

    It has been shown over the past few years that apolipoprotein E (apoE) plays a central role in the brain response to injury and neurodegeneration in mammalian species. The coordinated expression of apoE and its different receptors, the so-called LDL receptor family, appears to regulate the transport of cholesterol and phospholipids during the early and middle phases of the reinnervation in the adult mammalian brain. As neurons undergo dendritic remodelling and synaptogenesis using cholesterol internalization through the apoE/LDL receptor pathway, they progressively shut down 3,3-hydroxymethylglutaryl-Coenzyme A (HMG CoA) reductase activity, the rate-limiting enzyme in the synthesis of cholesterol. These results suggest that cholesterol delivery and synthesis in the brain are tightly regulated through an apoE-dependent mechanism. The discovery that the apolipoprotein e4 allele is strongly linked to both sporadic and familial late-onset Alzheimer's disease (AD) has raised the possibility that a dysfunction of lipid transport could explain the poor compensatory synaptogenesis reported by several independent research groups in the brain of AD subjects. Recently, it has been shown that alterations of cholesterol homeostasis in the brain by exogenous administration of dietary cholesterol, or through inhibition of cholesterol synthesis, markedly affect beta amyloid production (1-40 and 1-42) and deposition and significantly impair amyloid precursor protein (APP) metabolism. In vivo, it has been shown that breeding of APP-overexpressing mice with apoE knockout mice completely abolishes amyloid plaque deposition in the brain of hybrid animals, without affecting beta amyloid steady state levels. Conversely, introduction of the human apoE3 and apoE4 genes in APP-overexpressing mice drastically reduced beta amyloid deposition in the brain of hybrid mice, confirming the proposed biological role of apoE in the clearance of extracellular beta amyloid. These results indicate that

  19. Arsenic exposure accelerates atherogenesis in apolipoprotein E(-/-) mice.

    PubMed

    Simeonova, Petia P; Hulderman, Tracy; Harki, Dan; Luster, Michael I

    2003-11-01

    Epidemiologic studies have shown an association between elevated arsenic levels in drinking water and an increased risk of atherosclerosis and vascular diseases. The studies presented here were performed to evaluate the atherogenic potential of arsenic using a well-established and controlled animal model of human atherosclerosis, mice deficient in apolipoprotein E (ApoE), and in vitro systems including primary human vascular cells. Wild-type and ApoE-deficient mice were exposed to 20 or 100 microg/mL sodium arsenite in drinking water for 24 weeks. As assessed morphometrically, the size of grossly discernible lesions covering the intimal area of aorta were increased significantly in arsenic-treated ApoE-deficient mice compared with nontreated transgenic mice. This effect was not associated with increased levels of serum cholesterol but was accompanied by an accumulation of arsenic in the vessel wall. Introduction of cocoa butter into the diet for 2 weeks resulted in higher serum cholesterol levels and only slight increases in the lesion size in control or arsenic-exposed ApoE-deficient mice. There were no lesions observed in the wild-type C57BL6 mice, resistant to atherosclerosis, whether they received arsenic or control drinking water. In vitro studies, including primary aorta endothelial or smooth muscle cells, were conducted to evaluate whether arsenic induces cellular mechanisms relevant to atherogenesis such as endothelial dysfunction, lipid oxidation, and smooth muscle cell proliferation. Arsenic treatment does not modulate endothelial cell-mediated lipid oxidation or smooth muscle cell proliferation but induced the expression of genes coding inflammatory mediators, including interleukin-8. Induction of endothelial inflammatory activity may play a role in arsenic-related vascular effects.

  20. 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.

  1. 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

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

    PubMed Central

    Walker, L. C.; Parker, C. A.; Lipinski, W. J.; Callahan, M. J.; Carroll, R. T.; Gandy, S. E.; Smith, J. D.; Jucker, M.; Bisgaier, C. L.

    1997-01-01

    To assess the influence of age and diet on cerebral pathology in mice lacking apolipoprotein E (apoE), four male apoE knockout mice (epsilon -/-), and five male wild-type (epsilon +/+) littermate controls were placed on a high-fat/high-cholesterol diet for 7 weeks beginning at 17 months of age. All four aged knockout mice developed xanthomatous lesions in the brain consisting mostly of crystalline cholesterol clefts, lipid globules, and foam cells. Smaller xanthomas were confined mainly to the choroid plexus and ventral fornix in the roof of the third ventricle, occasionally extending subpially along the choroidal fissure and into the adjacent parenchyma. More advanced xanthomas disrupted adjoining neural tissue in the fornix, hippocampus, and dorsal diencephalon; in one case, over 60% of one telencephalic hemisphere, including nearly the entire neocortex, was obliterated by the lesion. No xanthomas were observed in aged wild-type controls fed the high-fat/high-cholesterol diet. Brains from 42 additional animals, fed only conventional chow, were examined; 3 of 15 aged (15- to 23-month-old) apoE knockout mice developed small choroidal xanthomas. In contrast, no lesions were observed in five young (2- to 4-month-old) apoE knockout mice or in any wild-type controls between the ages of 2 and 23 months. Our findings indicate that disorders of lipid metabolism can induce significant pathological changes in the central nervous system of aged apoE knockout mice, particularly those on a high-fat/high-cholesterol diet. It may be fruitful to seek potential interactions between genetic factors and diet in modulating the risk of Alzheimer's disease and other neurodegenerative disorders in aged humans. Images Figure 1 Figure 2 PMID:9358763

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

    PubMed

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

    2004-11-01

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

  4. 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

  5. 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

  6. 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

  7. Heterogeneity of apolipoprotein E polymorphism in different Mexican populations.

    PubMed

    Aceves, Dolores; Ruiz, Bertha; Nuño, Patricia; Roman, Sonia; Zepeda, Eloy; Panduro, Arturo

    2006-02-01

    Mexico has approximately 100 million inhabitants. Most of the urban Mexican population has been considered mestizo (Indian and Spanish descent), whereas the Indian population predominates in rural areas and small towns in the countryside. In this study we analyzed the apolipoprotein E (APOE) polymorphism in Guadalajara (the second largest metropolitan area of Mexico) and its surrounding areas, two adjoining states (Nayarit and Durango), and an Indian town (Huichol Indians) from western Mexico. APOE*3 was the most common allele, and APOE*3/*3 was the most common genotype in all populations studied. Guadalajara revealed the highest frequency of the APOE*2 allele (7.8%); the frequency decreased in the rural area (4.4%), followed by Nayarit (1.6%), and was absent in Durango and in the Huichols. On the contrary, the lowest frequency of the APOE*4 allele was in Guadalajara (8.4%); the frequency increased in the rural area (9.3%), in Nayarit and Durango (11.5% and 11.7%), and reached a high frequency in the Huichol Indians (28%). The distribution of the APOE allele in the western population of Mexico is similar to those described in Mexican American migrants living in the United States but is different from those populations living in Mexico City. This study shows the heterogeneity of the Mexican population, where the frequency of the APOE*2 allele is higher in Guadalajara than in other urban areas of Mexico and is similar to frequencies described in the Caucasian population. On the contrary, the Huichols revealed the highest frequency of the APOE*4 allele in Mexico and in the Americas. This information could be useful for the study of dyslipidemias associated with chronic diseases and as markers of ethnic variation in the Americas.

  8. 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

  9. 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.

  10. 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

  11. 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

  12. Members of the DAN Family are BMP Antagonists that form Highly Stable Noncovalent Dimers

    PubMed Central

    Kattamuri, Chandramohan; Luedeke, David M.; Nolan, Kristof; Rankin, Scott A.; Greis, Kenneth D.; Zorn, Aaron M.; Thompson, Thomas B.

    2012-01-01

    Signaling of BMP ligands is antagonized by a number of extracellular proteins, including noggin, follistatin and members of the DAN family. Structural studies on the DAN family member sclerostin (a weak BMP antagonist) have previously revealed that the protein is monomeric and consists of an 8-membered cystine knot motif with a fold similar to TGF-β ligands. In contrast to sclerostin, certain DAN family antagonists, including Protein related to DAN and Cerberus (PRDC), have an unpaired cysteine that is thought to function in covalent dimer assembly (analogous to TGF-β ligands). Through a combination of biophysical and biochemical studies, we determined that PRDC forms biologically active dimers that potently inhibit BMP ligands. Furthermore, we showed that PRDC dimers, surprisingly, are not covalently linked, as mutation of the unpaired cysteine does not inhibit dimer formation or biological activity. We further demonstrated that the noncovalent PRDC dimers are highly stable under both denaturing and reducing conditions. This study was extended to the founding family member DAN, which also forms noncovalent dimers that are highly stable. These results demonstrate that certain DAN family members can form both monomers and noncovalent dimers, implying that biological activity of DAN family members might be linked to their oligomeric state. PMID:23063586

  13. Neuropathological changes in scrapie and Alzheimer's disease are associated with increased expression of apolipoprotein E and cathepsin D in astrocytes.

    PubMed Central

    Diedrich, J F; Minnigan, H; Carp, R I; Whitaker, J N; Race, R; Frey, W; Haase, A T

    1991-01-01

    With the rationale that the neuropathological similarities between scrapie and Alzheimer's disease reflect convergent pathological mechanisms involving altered gene expression, we set out to identify molecular events involved in both processes, using scrapie as a model to study the time course of these changes. We differentially screened a cDNA library constructed from scrapie-infected mice to identify mRNAs that increase or decrease during disease and discovered in this way two mRNAs that are increased in scrapie and Alzheimer's disease. These mRNAs were subsequently shown by sequence analysis to encode apolipoprotein E and cathepsin D (EC 3.4.23.5). Using in situ hybridization and immunocytochemistry to define the cellular and anatomic pathology of altered gene expression, we found that in both diseases the increase in apolipoprotein E and cathepsin D mRNAs and proteins occurred in activated astrocytes. In scrapie, the increase in gene expression occurred soon after the amyloid-forming abnormal isoform of the prion protein has been shown to accumulate in astrocytes. In Alzheimer's disease, the increased expression of cathepsin D also occurred in association with beta-amyloid. These studies reveal some of the molecular antecedents of neuropathological changes in scrapie and Alzheimer's disease and accord new prominence to the role of astrocytes in neurodegenerative conditions. Images PMID:1870200

  14. 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

  15. Computational Design of Apolipoprotein E4 Inhibitors for Alzheimer's Disease Therapy from Traditional Chinese Medicine

    PubMed Central

    Huang, Hung-Jin; Chen, Hsin-Yi; Lee, Cheng-Chun

    2014-01-01

    Apolipoprotein E4 (Apo E4) is the major genetic risk factor in the causation of Alzheimer's disease (AD). In this study we utilize virtual screening of the world's largest traditional Chinese medicine (TCM) database and investigate potential compounds for the inhibition of ApoE4. We present the top three TCM candidates: Solapalmitine, Isodesacetyluvaricin, and Budmunchiamine L5 for further investigation. Dynamics analysis and molecular dynamics (MD) simulation were used to simulate protein-ligand complexes for observing the interactions and protein variations. Budmunchiamine L5 did not have the highest score from virtual screening; however, the dynamics pose is similar to the initial docking pose after MD simulation. Trajectory analysis reveals that Budmunchiamine L5 was stable over all simulation times. The migration distance of Budmunchiamine L5 illustrates that docked ligands are not variable from the initial docked site. Interestingly, Arg158 was observed to form H-bonds with Budmunchiamine L5 in the docking pose and MD snapshot, which indicates that the TCM compounds could stably bind to ApoE4. Our results show that Budmunchiamine L5 has good absorption, blood brain barrier (BBB) penetration, and less toxicity according to absorption, distribution, metabolism, excretion, and toxicity (ADMET) prediction and could, therefore, be safely used for developing novel ApoE4 inhibitors. PMID:24967370

  16. Computational design of apolipoprotein E4 inhibitors for Alzheimer's disease therapy from traditional Chinese medicine.

    PubMed

    Huang, Hung-Jin; Chen, Hsin-Yi; Lee, Cheng-Chun; Chen, Calvin Yu-Chian

    2014-01-01

    Apolipoprotein E4 (Apo E4) is the major genetic risk factor in the causation of Alzheimer's disease (AD). In this study we utilize virtual screening of the world's largest traditional Chinese medicine (TCM) database and investigate potential compounds for the inhibition of ApoE4. We present the top three TCM candidates: Solapalmitine, Isodesacetyluvaricin, and Budmunchiamine L5 for further investigation. Dynamics analysis and molecular dynamics (MD) simulation were used to simulate protein-ligand complexes for observing the interactions and protein variations. Budmunchiamine L5 did not have the highest score from virtual screening; however, the dynamics pose is similar to the initial docking pose after MD simulation. Trajectory analysis reveals that Budmunchiamine L5 was stable over all simulation times. The migration distance of Budmunchiamine L5 illustrates that docked ligands are not variable from the initial docked site. Interestingly, Arg158 was observed to form H-bonds with Budmunchiamine L5 in the docking pose and MD snapshot, which indicates that the TCM compounds could stably bind to ApoE4. Our results show that Budmunchiamine L5 has good absorption, blood brain barrier (BBB) penetration, and less toxicity according to absorption, distribution, metabolism, excretion, and toxicity (ADMET) prediction and could, therefore, be safely used for developing novel ApoE4 inhibitors.

  17. 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

  18. Anionic phospholipids inhibit apolipoprotein E--low-density lipoprotein receptor interactions.

    PubMed

    Yamamoto, Taichi; Ryan, Robert O

    2007-03-16

    Apolipoprotein E (apoE) is a ligand for members of the low-density lipoprotein receptor (LDLR) family. Lipid-free apoE is not recognized by LDLR, yet interaction with lipid confers receptor recognition properties. Although lipid interaction is known to induce a conformational change in apoE, it is not known if the lipid composition of the resulting complex influences binding. Using reconstituted lipoprotein particles of apoE3 N-terminal (NT) domain and dimyristoylphosphatidylcholine (DMPC), maximal LDLR binding was observed at DMPC:apoE3-NT ratios >2.5:1 (w/w). ApoE3-NT lipid particles prepared with egg sphingomyelin were functional as LDLR ligands while complexes formed with the anionic phospholipids dimyristoylphosphatidylglycerol or dimyristoylphosphatidylserine (DMPS) were not. In the case of apoE3-NT, lipid particles comprised of a mixture of DMPC and DMPS, a DMPS concentration dependent inhibition of LDLR binding activity was observed. Thus, in addition to affecting apoE conformational status, the lipid composition of ligand particles can modulate LDLR binding activity.

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

    PubMed

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

    2014-12-01

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

  20. 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 ...

  1. 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…

  2. 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 ...

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

    PubMed

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

    2007-08-01

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

  4. Volumes of hippocampus, amygdala and frontal lobe in Alzheimer patients with different apolipoprotein E genotypes.

    PubMed

    Lehtovirta, M; Laakso, M P; Soininen, H; Helisalmi, S; Mannermaa, A; Helkala, E L; Partanen, K; Ryynänen, M; Vainio, P; Hartikainen, P

    1995-07-01

    An increased frequency of apolipoprotein E E4 allele has been reported in patients with late onset Alzheimer's disease. Apolipoprotein E participates in the transport of cholesterol and other lipids and interferes with the growth and regeneration of both peripheral and central nervous system tissues during development and after injury. Apolipoprotein E is also implicated in synaptogenesis. Apolipoprotein E isoforms differ in binding to amyloid-beta-protein and tau protein in vitro. Here, we wanted to study the effect of apolipoprotein E genotype on the magnitude of damage in the hippocampus, where a marked synapse loss exists in Alzheimer's disease. We measured by magnetic resonance imaging the volumes of the hippocampus, amygdala, and frontal lobes in the three Alzheimer subgroups: patients with 2, 1 or 0 E4 alleles. We also investigated the profile of deficits on tests assessing memory, language, visuospatial, executive, and praxic functions of these Alzheimer subgroups. All Alzheimer patients were at early stage of the disease. We found that Alzheimer patients with E4/4 genotype (N = 5) had smaller volumes of the hippocampus and the amygdala than those with E3/4 (N = 9) and those with E3/3 or E2/3 (N = 12). The difference was significant for the right hippocampus (-54% of control) and the right amygdala (-37% of control). The volumes of the frontal lobes were similar across the Alzheimer subgroups. The patients with E4/4 also showed lowest scores on delayed memory tests and differed from E3/3, 3/2 patients in the list learning test (< 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Effect of Molecular Structure on Stability of Organic Nanoparticles Formed by Bodipy Dimers.

    PubMed

    Lin, Wenhai; Zhang, Wei; Sun, Tingting; Gu, Jingkai; Xie, Zhigang; Jing, Xiabin

    2016-09-20

    The objective was to evaluate the stability of organic nanoparticles made from Bodipy dimers. Bodipy dimers with different length of linkers were synthesized via multicomponent Passerini reaction, and could form the fluorescent nanoparticles (FNPs) through nanoprecipitation. Bodipy-dimers FNPs with long chain linker indicated better stability in biological condition than those with short one as revealed by changes of diameter and size distribution. The FNPs possessed high physical homogeneity and low cytotoxicity. The molecular structure dependent stability was also validated by confocal laser scanning microscope based on the dissociation-induced fluorescence recovering. Importantly, stable FNPs also could be used to load hydrophobic cargoes and deliver them into cytoplasm. We believe this systematic study between structure and stability might open new opportunities for designing stable nanoparticles for various applications. PMID:27571251

  6. Zinc affects the proteolytic stability of Apolipoprotein E in an isoform-dependent way.

    PubMed

    Xu, He; Gupta, Veer B; Martins, Ian J; Martins, Ralph N; Fowler, Christopher J; Bush, Ashley I; Finkelstein, David I; Adlard, Paul A

    2015-09-01

    The pathological role of zinc in Alzheimer's disease (AD) is not yet fully elucidated, but there is strong evidence that zinc homeostasis is impaired in the AD brain and that this contributes to disease pathogenesis. In this study we examined the effects of zinc on the proteolysis of synthetic Apolipoprotein E (ApoE), a protein whose allelic variants differentially contribute to the onset/progression of disease. We have demonstrated that zinc promotes the proteolysis (using plasma kallikrein, thrombin and chymotrypsin) of synthetic ApoE in an isoform-specific way (E4>E2 and E3), resulting in more ApoE fragments, particularly for ApoE4. In the absence of exogenous proteases there was no effect of metal modulation on either lipidated or non-lipidated ApoE isoforms. Thus, increased zinc in the complex milieu of the ageing and AD brain could reduce the level of normal full-length ApoE and increase other forms that are involved in neurodegeneration. We further examined human plasma samples from people with different ApoE genotypes. Consistent with previous studies, plasma ApoE levels varied according to different genotypes, with ApoE2 carriers showing the highest total ApoE levels and ApoE4 carriers the lowest. The levels of plasma ApoE were not affected by either the addition of exogenous metals (copper, zinc or iron) or by chelation. Taken together, our study reveals that zinc may contribute to the pathogenesis of AD by affecting the proteolysis of ApoE, which to some extent explains why APOE4 carriers are more susceptible to AD.

  7. 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

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

    PubMed

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

    2016-09-15

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

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

    PubMed

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

    2016-09-15

    Ezrin is a member of the ERM (ezrin-radixin-moesin) family of proteins that have been conserved through metazoan evolution. These proteins have dormant and active forms, where the latter links the actin cytoskeleton to membranes. ERM proteins have three domains: an N-terminal FERM [band Four-point-one (4.1) ERM] domain comprising three subdomains (F1, F2, and F3); a helical domain; and a C-terminal actin-binding domain. In the dormant form, FERM and C-terminal domains form a stable complex. We have determined crystal structures of the active FERM domain and the dormant FERM:C-terminal domain complex of human ezrin. We observe a bistable array of phenylalanine residues in the core of subdomain F3 that is mobile in the active form and locked in the dormant form. As subdomain F3 is pivotal in binding membrane proteins and phospholipids, these transitions may facilitate activation and signaling. Full-length ezrin forms stable monomers and dimers. We used small-angle X-ray scattering to determine the solution structures of these species. As expected, the monomer shows a globular domain with a protruding helical coiled coil. The dimer shows an elongated dumbbell structure that is twice as long as the monomer. By aligning ERM sequences spanning metazoan evolution, we show that the central helical region is conserved, preserving the heptad repeat. Using this, we have built a dimer model where each monomer forms half of an elongated antiparallel coiled coil with domain-swapped FERM:C-terminal domain complexes at each end. The model suggests that ERM dimers may bind to actin in a parallel fashion. PMID:27364155

  10. 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).

  11. 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.

  12. 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.

  13. 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.

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

    PubMed

    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.

  15. 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.

  16. Does Apolipoprotein E genotype affect cardiovascular risk in subjects with acromegaly?

    PubMed

    Bozok Cetintas, Vildan; Zengi, Ayhan; Tetik, Asli; Karadeniz, Muammer; Ergonen, Faruk; Kucukaslan, Ali Sahin; Tamsel, Sadik; Kosova, Buket; Sahin, Serap Baydur; Saygılı, Fusun; Eroglu, Zuhal

    2012-06-01

    Acromegaly is a syndrome that results when the pituitary gland produces excess growth hormone after epiphyseal closure at puberty. Usually, subjects with acromegaly exhibit a 2- to 3-fold higher mortality rate from diseases that are associated with cardiovascular complications when compared to the normal population. In this study, we therefore aimed to evaluate whether a well-established cardiovascular risk factor, the Apolipoprotein E (Apo E) genotype, contributes to increased risk of cardiovascular complications in subjects with acromegaly. A total of 102 unrelated acromegaly subjects were prospectively included into this case-control association study and constituted our study group. The study group was comparable by age and gender with 200 unrelated healthy subjects constituting our control group. Genomic DNA was isolated from the peripheral blood leukocytes of all subjects and Apo E genotype (codon 112/158) was assessed by melting temperature analyses after using a real-time PCR protocol. The Apolipoprotein E4 allele was found at a significantly higher frequency in the study group when compared with the control group (P = 0.032). Subjects with the E2 allele, on the other hand, had significantly increased values in body mass index (P = 0.004), waist circumference (P = 0.001), C-reactive protein (CRP) (P < 0.001), and left-side carotid intima media thickness (P = 0.025). The Apolipoprotein E2 genotype might contribute to increased risk of cardiovascular complications in subjects with acromegaly since it is concurrently present with other cardiovascular risk factors such as the left-side carotid intima media thickness and CRP.

  17. 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.

  18. 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

  19. Supramolecular hydrogels formed from poly(viologen) cross-linked with cyclodextrin dimers and their physical properties

    PubMed Central

    Takashima, Yoshinori; Yuting, Yang; Otsubo, Miyuki; Yamaguchi, Hiroyasu

    2012-01-01

    Summary Supramolecular materials with noncovalent bonds have attracted much attention due to their exclusive properties differentiating them from materials formed solely by covalent bonds. Especially interesting are rotor molecules of topological complexes that shuttle along a polymer chain. The shuttling of these molecules should greatly improve the tension strength. Our research employs cyclodextrin (CD) as a host molecule, because CD effectively forms polyrotaxanes with polymers. Herein we report the formation of supramolecular hydrogels with an α-CD dimer (α,α-CD dimer) as a topological linker molecule, and a viologen polymer (VP) as the polymer chain. The supramolecular hydrogel of α,α-CD dimer/VP forms a self-standing gel, which does not relax (G' > G'') in the frequency range 0.01–10 rad·s−1. On the other hand, the supramolecular hydrogel decomposes upon addition of bispyridyl decamethylene (PyC10Py) as a competitive guest. Moreover, the β-CD dimer (β,β-CD dimer) with VP does not form a supramolecular hydrogel, indicating that complexation between the C10 unit of VP and the α-CD unit of the α,α-CD dimer plays an important role in the formation of supramolecular hydrogels. PMID:23209491

  20. Reduced telomere length in subjects with dementia and diabetes mellitus type 2 is independent of apolipoprotein E4 genotype.

    PubMed

    Kota, Lakshmi Narayanan; Bharath, Srikala; Purushottam, Meera; Paul, Pradip; Sivakumar, Palanimuthu Thangaraju; Varghese, Mathew; Jain, Sanjeev

    2014-12-01

    Apolipoprotein E4 gene is associated with increased risk of dementia with comorbid diabetes mellitus. Both dementia and diabetes mellitus type 2 are independently associated with telomere shortening. We assessed relative telomere length and apolipoprotein E genotype in subjects with dementia (n=70) and cognitively normal control groups (n=55) with and without comorbid diabetes mellitus type 2. Relative telomere length was highest in the control group (Q2=0.91) followed by dementia (Q2=0.48) and dementia with comorbid diabetes mellitus type 2 (Q2=0.39). Apolipoprotein E4 allele frequency was highest in dementia with comorbid diabetes mellitus type 2 (0.26). Apolipoprotein E4 allele was not significantly associated with telomere attrition in both dementia and cognitively normal group irrespective of comorbid diabetes mellitus type 2 (P>0.05). The findings suggest that relative telomere length is unrelated to apolipoprotein E4 genotype in dementia and cognitive normal subjects with or without comorbid diabetes mellitus type 2.

  1. 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.

  2. Interleukin-10 Deficiency Increases Atherosclerosis, Thrombosis, and Low-density Lipoproteins in Apolipoprotein E Knockout Mice

    PubMed Central

    Caligiuri, Giuseppina; Rudling, Mats; Ollivier, Véronique; Jacob, Marie-Paule; Michel, Jean-Baptiste; Hansson, Göran K; Nicoletti, Antonino

    2003-01-01

    Interleukin (IL)-10 is an anti-inflammatory cytokine that may play a protective role in atherosclerosis. The aim of this study was to assess the effect of IL-10 deficiency in the apolipoprotein E knockout mouse. Apolipoprotein E deficient (E−/−) and IL-10 deficient (−/−) mice were crossed to generate E−/− × IL-10−/− double knockout mice. By 16 wk, cholesterol and triglycerides were similar in double and single knockouts but the lack of IL-10 led to increased low-density lipoprotein cholesterol whereas very-low-density lipoprotein was reduced. In parallel, T-helper 1 responses and lesion size were dramatically increased in double knockout compared with E−/− controls. At 48 wk, matrix metalloproteinases and tissue factor activities were increased in lesions of double-knockout mice. Furthermore, markers of systemic coagulation were increased, and vascular thrombosis in response to i.v. thrombin occurred more frequently in E−/− × IL-10−/− than in E−/− mice. Our findings suggest that IL-10 deficiency plays a deleterious role in atherosclerosis. The early phase of lesion development was increased, and the proteolytic and procoagulant activity was elevated in advanced lesions. These data show that IL-10 may reduce atherogenesis and improve the stability of plaques. PMID:12765335

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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

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

    PubMed

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

    2009-08-01

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

  9. 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

  10. Construction of a dimeric form of glutamate dehydrogenase from Clostridium symbiosum by site-directed mutagenesis.

    PubMed

    Pasquo, A; Britton, K L; Stillman, T J; Rice, D W; Cölfen, H; Harding, S E; Scandurra, R; Engel, P C

    1996-10-17

    basis of this, sedimentation equilibrium experiments were performed over a range of protein concentrations. M(r,app) showed a linear dependence on concentration and a value of 108 118 g/mol at infinite dilution. This indicates a rapid equilibrium between dimeric and hexameric forms of the mutant protein with an equilibrium constant of 0.13 l/g. An independent analysis of the radial absorption scans with Microcal Origin software indicated a threefold association constant of 0.11 l/g. Introduction of the F187D mutation thus appears to have been successful in producing a dimeric GDH species. Since this protein is inactive it is possible that activity requires subunit interaction around the 3-fold symmetry axis. On the other hand this mutation may disrupt the structure in a way that cannot be extrapolated to other dimers. This issue can only be resolved by making alternative dimeric mutants.

  11. 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

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

    PubMed

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

    2014-12-08

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

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

    PubMed Central

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

    2014-01-01

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

  14. 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.

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

    PubMed

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

    2010-01-01

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

  16. 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

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

    PubMed

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

    1994-03-01

    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.

  18. 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

  19. 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.

  20. A pyrene based fluorescence approach to study conformation of apolipoprotein E3 in macrophage-generated nascent high density lipoprotein.

    PubMed

    Kim, Sea H; Kothari, Shweta; Patel, Arti B; Bielicki, John K; Narayanaswami, Vasanthy

    2014-07-18

    Apolipoprotein E3 (apoE3) is an anti-atherogenic apolipoprotein with the ability to exist in lipid-free and lipoprotein-associated states. During atherosclerosis, its function in promoting cholesterol efflux from macrophages via the ATP-binding cassette transporter A1 (ABCA1) takes a prominent role, leading to generation of nascent high density lipoprotein (nHDL) particles. The objective of this study is to understand the conformation adopted by apoE3 in macrophage-generated nHDL using a fluorescence spectroscopic approach involving pyrene. Pyrene-labeled recombinant human apoE3 displayed a robust ability to stimulate ABCA1-mediated cholesterol efflux from cholesterol-loaded J774 macrophages (which do not express apoE), comparable to that elicited by unlabeled apoE3. The nHDL recovered from the conditioned medium revealed the presence of apoE3 by immunoblot analysis. A heterogeneous population of nHDL bearing exogenously added apoE3 was generated with particle size varying from ∼12 to ∼19 nm in diameter, corresponding to molecular mass of ∼450 to ∼700 kDa. The lipid: apoE3 ratio varied from ∼60:1 to 10:1. A significant extent of pyrene excimer emission was noted in nHDL, indicative of spatial proximity between Cys112 on neighboring apoE3 molecules similar to that noted in reconstituted HDL. Cross-linking analysis using Cys-specific cross-linkers revealed the predominant presence of dimers. Taken together the data indicate a double belt arrangement of apoE molecules on nHDL. A similar organization of the C-terminal tail of apoE on nHDL was noted when pyrene-apoEA277C(201-299) was used as the cholesterol acceptor. These studies open up the possibility of using exogenously labeled apoE3 to generate nHDL for structural and conformational analysis.

  1. 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.

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

    PubMed

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

    2016-04-13

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

  3. 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

  4. 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

  5. Rapid apolipoprotein E radioimmunoassay using solid-phase staphylococcus protein. Use of pooled plasma as a secondary standard

    SciTech Connect

    Au, Y.P.T.; Bren, N.D.; Kottke, B.A.

    1986-07-16

    A rapid apolipoprotein E (apo E) radioimmunoassay, which requires a total of 24 hour incubation as compared to the usual 3-5 days, has been developed in their laboratory. Solid phase staphylococcus protein A was used to separate bound and unbound labeled antigen. Use of a pooled plasma (quality control sample) as a secondary standard to reduce interassay variation was also described.

  6. An analysis of genotype effects and their interactions by using the apolipoprotein E polymorphism and longitudinal data.

    PubMed Central

    Gueguen, R; Visvikis, S; Steinmetz, J; Siest, G; Boerwinkle, E

    1989-01-01

    We investigate the interaction between the apolipoprotein E polymorphism and changes in weight and height as they affect the longitudinal profile of total cholesterol, triglyceride, beta lipoprotein, and glucose levels. Data were available on a sample of 466 individuals in 158 nuclear families from Nancy, France. Longitudinal data analyses were carried out on 128 unrelated adults and 56 unrelated children. We estimate the relative frequencies of the epsilon 2, epsilon 3, and epsilon 4 apolipoprotein E alleles in this population to be .120, .764, and .116, respectively. There is no significant evidence from these data that supports an effect of the apolipoprotein E polymorphism on the longitudinal profile of any of the variables considered. There is a significant interaction between the effects of this gene and weight change on the longitudinal change of serum triglyceride and beta lipoprotein levels in adults. In conjunction with weight gain, individuals with an epsilon 4 allele are expected to show a larger increase in triglyceride levels (0.15 +/- 0.03 mmol/L/kg) compared with individuals with no epsilon 4 allele. An increased production of very-low-density lipoprotein (VLDL) as one gains weight, along with retarded VLDL clearance attributable to the effects of the epsilon 4 allele, may account for this results. The significant interaction between the apolipoprotein E polymorphism and changes in weight on the longitudinal change in triglyceride levels corroborates epidemiological studies reporting that the epsilon 4 allele increases the risk of hypertriglyceridemia among obese individuals. PMID:2816943

  7. 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

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

    PubMed

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

    2014-09-01

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

  9. 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.

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

    PubMed

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

    2015-11-01

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

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

    PubMed

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

    2014-01-13

    Apolipoprotein E (ApoE) is found in three different forms in humans (ApoE2, ApoE3 and ApoE4), and ApoE polymorphism is recognized as a major risk factor for Alzheimer's disease (AD). ApoE is involved in lipid and cholesterol transport, cell repair, and amyloid-β deposition and certain studies suggest potential implications in neurogenesis. In this regard, we investigated the possible impact of the three different human ApoE isoforms on neurogenesis. We used ApoE knock-in mice of different ages and sex, and quantified newborn cells in the hippocampus by flow cytometry. Young adult ApoE4 mice (10-12 week-old) from both sexes displayed reduced neurogenesis compared with wild-types and the other genotypes. In addition, young adult ApoE2 female mice showed improved hippocampal progenitor cell proliferation. In older mice (1 year), hippocampal neurogenesis was globally decreased, particularly in females, and the difference between ApoE4 and the other genotypes observed in young animals disappeared for the two sexes, except for aged ApoE3 females. Indeed, a surprising protective effect of the ApoE3 genotype was observed in aged females. Our study highlights the role of ApoE in neurogenesis, and shows for the first time an early inequality between the ApoE genotypes. The reduced neurogenesis observed for the ApoE4 genotype and the improved results obtained in young ApoE2 females support the idea of a difference in the balance between neuronal birth and death modulated by the ApoE polymorphism in young animals. The maintenance of this balance and its modulation can influence pathophysiological mechanisms predisposing to neurodegenerative diseases like AD. PMID:24140109

  12. 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

  13. 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.

  14. Apolipoprotein E4 reduces evoked hippocampal acetylcholine release in adult mice.

    PubMed

    Dolejší, Eva; Liraz, Ori; Rudajev, Vladimír; Zimčík, Pavel; Doležal, Vladimír; Michaelson, Daniel M

    2016-02-01

    Apolipoprotein E4 (apoE4) is the most prevalent genetic risk factor for Alzheimer's disease. We utilized apoE4-targeted replacement mice (approved by the Tel Aviv University Animal Care Committee) to investigate whether cholinergic dysfunction, which increases during aging and is a hallmark of Alzheimer's disease, is accentuated by apoE4. This revealed that levels of the pre-synaptic cholinergic marker, vesicular acetylcholine transporter in the hippocampus and the corresponding electrically evoked release of acetylcholine, are similar in 4-month-old apoE4 and apolipoprotein E3 (apoE3) mice. Both parameters decrease with age. This decrease is, however, significantly more pronounced in the apoE4 mice. The levels of cholinacetyltransferase (ChAT), acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) were similar in the hippocampus of young apoE4 and apoE3 mice and decreased during aging. For ChAT, this decrease was similar in the apoE4 and apoE3 mice, whereas it was more pronounced in the apoE4 mice, regarding their corresponding AChE and BuChE levels. The level of muscarinic receptors was higher in the apoE4 than in the apoE3 mice at 4 months and increased to similar levels with age. However, the relative representation of the M1 receptor subtype decreased during aging in apoE4 mice. These results demonstrate impairment of the evoked release of acetylcholine in hippocampus by apoE4 in 12-month-old mice but not in 4-month-old mice. The levels of ChAT and the extent of the M2 receptor-mediated autoregulation of ACh release were similar in the adult mice, suggesting that the apoE4-related inhibition of hippocampal ACh release in these mice is not driven by these parameters. Evoked ACh release from hippocampal and cortical slices is similar in 4-month-old apoE4 and apoE3 mice but is specifically and significantly reduced in hippocampus, but not cortex, of 12-month-old apoE4 mice. This effect is accompanied by decreased VAChT levels. These findings show that

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

    PubMed

    Rao, K N; Suresh, C G

    2007-10-01

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

  16. 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.

  17. Neuronal Regulation of Neuroprotective Microglial Apolipoprotein E Secretion in Rat In Vitro Models of Brain Pathophysiology.

    PubMed

    Polazzi, Elisabetta; Mengoni, Ilaria; Peña-Altamira, Emiliano; Massenzio, Francesca; Virgili, Marco; Petralla, Sabrina; Monti, Barbara

    2015-08-01

    Apolipoprotein E (ApoE) is mainly secreted by glial cells and is involved in many brain functions, including neuronal plasticity, β-amyloid clearance, and neuroprotection. Microglia--the main immune cells of the brain--are one source of ApoE, but little is known about the physiologic regulation of microglial ApoE secretion by neurons and whether this release changes under inflammatory or neurodegenerative conditions. Using rat primary neural cell cultures, we show that microglia release ApoE through a Golgi-mediated secretion pathway and that ApoE progressively accumulates in neuroprotective microglia-conditioned medium. This constitutive ApoE release is negatively affected by microglial activation both with lipopolysaccharide and with ATP. Microglial ApoE release is stimulated by neuron-conditioned media and under coculture conditions. Neuron-stimulated microglial ApoE release is mediated by serine and glutamate through N-methyl-D-aspartate receptors and is differently regulated by activation states (i.e. lipopolysaccharide vs ATP) and by 6-hydroxydopamine. Microglial ApoE silencing abrogated protection of cerebellar granule neurons against 6-hydroxydopamine toxicity in cocultures, indicating that microglial ApoE release is neuroprotective. Our findings shed light on the reciprocal cross-talk between neurons and microglia that is crucial for normal brain functions. They also open the way for the identification of possible pharmacologic targets that can modulate neuroprotective microglial ApoE release under pathologic conditions.

  18. 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

  19. 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.

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

    PubMed

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

    2010-01-01

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

  1. 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

  2. Reduced cortical thickness in hippocampal sub-regions among cognitively normal apolipoprotein E e4 carriers

    PubMed Central

    Burggren, A. C.; Zeineh, M. M.; Ekstrom, A. D.; Braskie, M. N.; Thompson, P. M.; Small, G. W.

    2008-01-01

    Our objective was to investigate whether asymptomatic carriers of apolipoprotein E ε4 [APOE-4] demonstrate pathological differences and atrophy in medial temporal lobe (MTL) sub-regions. We measured cortical thickness and volume in MTL sub-regions (hippocampal CA fields 1, 2 and 3; dentate gyrus; entorhinal cortex; subiculum; perirhinal cortex; parahippocampal cortex; and fusiform gyrus) using a high-resolution in-plane (.4×.4mm) MRI sequence in 30 cognitively normal volunteers (14 APOE–4 carriers, 16 non-carriers, mean age 57 years). A cortical unfolding procedure maximized visibility of this convoluted cortex, providing cortical ribbon thickness measures throughout individual subregions of the hippocampus and surrounding cortex. APOE–4 carriers had reduced cortical thickness compared with non-carriers in entorhinal cortex (ERC) and the subiculum (Sub), but not in the main hippocampal body or perirhinal cortex. Average cortical thickness was 14.8% lower (p=1.0e−6) for ERC and 12.6% lower (p=6.8e−5) for Sub in APOE-4 carriers. Standard volumetric measures of the same regions showed similar, but non-significant trends. Cognitively intact carriers of APOE-4 show regionally specific thinning of the cortical ribbon compared to APOE-3 carriers; cortical thickness may be a more sensitive measure of pathological differences in genetic risk subjects than standard volumetry. PMID:18486492

  3. 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

  4. 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

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

    PubMed

    Merritt, Victoria C; Arnett, Peter A

    2016-01-01

    Exploring the relationship between genetic factors and outcome following brain injury has received increased attention in recent years. However, few studies have evaluated the influence of genes on specific sequelae of concussion. The purpose of this study was to determine how the ϵ4 allele of the apolipoprotein E (APOE) gene influences symptom expression following sports-related concussion. Participants included 42 collegiate athletes who underwent neuropsychological testing, including completion of the Post-Concussion Symptom Scale (PCSS), within 3 months after sustaining a concussion (73.8% were evaluated within 1 week). Athletes provided buccal samples that were analyzed to determine the make-up of their APOE genotype. Dependent variables included a total symptom score and four symptom clusters derived from the PCSS. Mann-Whitney U tests showed higher scores reported by athletes with the ϵ4 allele compared to those without it on the total symptom score and the physical and cognitive symptom clusters. Furthermore, logistic regression showed that the ϵ4 allele independently predicted those athletes who reported physical and cognitive symptoms following concussion. These findings illustrate that ϵ4+ athletes report greater symptomatology post-concussion than ϵ4- athletes, suggesting that the ϵ4 genotype may confer risk for poorer post-concussion outcome. (JINS, 2016, 22, 89-94). PMID:26483005

  6. 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

  7. Di-(2-ethylhexyl) phthalate accelerates atherosclerosis in apolipoprotein E-deficient mice.

    PubMed

    Zhao, Jin-Feng; Hsiao, Sheng-Huang; Hsu, Ming-Hua; Pao, Kuan-Chuan; Kou, Yu Ru; Shyue, Song-Kun; Lee, Tzong-Shyuan

    2016-01-01

    Di-(2-ethylhexyl) phthalate (DEHP) is associated with atherosclerosis-related cardiovascular disease complications, but we lack direct evidence of its unfavorable effect on atherogenesis. In this study, we aimed to clarify in vivo and in vitro the contribution of DEHP to the development of atherosclerosis and its underlying mechanisms. Apolipoprotein E-deficient (apoE(-/-)) mice chronically treated with DEHP for 4 weeks showed exacerbated hyperlipidemia, systemic inflammation, and atherosclerosis. In addition, DEHP promoted low-density lipoprotein (LDL) oxidation, which led to inflammation in endothelial cells as evidenced by increased protein expression of pro-inflammatory mediators. Furthermore, chronic DEHP treatment increased hepatic cholesterol accumulation by downregulating the protein expression of key regulators in cholesterol clearance including LDL receptor, cholesterol 7α-hydrolase, ATP-binding cassette transporter G5 and G8, and liver X receptor α. Moreover, the adiposity and inflammation of white adipose tissues were promoted in DEHP-treated apoE(-/-) mice. In conclusion, DEHP may disturb cholesterol homeostasis and deregulate the inflammatory response, thus leading to accelerated atherosclerosis.

  8. 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.

  9. 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

  10. Epistatic effect of APP717 mutation and apolipoprotein E genotype in familial Alzheimer's disease.

    PubMed

    Sorbi, S; Nacmias, B; Forleo, P; Piacentini, S; Latorraca, S; Amaducci, L

    1995-07-01

    We found a new familial Alzheimer's disease kindred in which the disease cosegregates with the APP717Val-->Ile mutation and in which all of the three most common apolipoprotein E (ApoE) alleles are represented. We studied the relationship between ApoE genotype and the clinical expression of the disease and found that in this amyloid precursor protein-mutated family, ApoE genotype influences the age at onset of the disease. Three mutated subjects heterozygous for the epsilon 4 allele had the earliest age at onset in this family, subjects heterozygous for the epsilon 2 allele had the latest age at onset, and subjects homozygous for the epsilon 3 allele had an intermediate age at onset. In this large kindred we also found an amyloid precursor protein-mutated subject 2.4 standard deviations older than the mean age at onset without clinical signs and symptoms of the disease and carrying the epsilon 2/epsilon 3 genotype. PMID:7611715

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

    PubMed

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

    2011-06-01

    Radiation exposure from a number of terrestrial sources is associated with an increased risk for atherosclerosis. Recently, concern over whether exposure to cosmic radiation might pose a similar risk for astronauts has increased. To address this question, we examined the effect of 2 to 5 Gy iron ions ((56)Fe), a particularly damaging component of cosmic radiation, targeted to specific arterial sites in male apolipoprotein E-deficient (apoE(-/-)) mice. Radiation accelerated the development of atherosclerosis in irradiated portions of the aorta independent of any systemic effects on plasma lipid profiles or circulating leukocytes. Further, radiation exposure resulted in a more rapid progression of advanced aortic root lesions, characterized by larger necrotic cores associated with greater numbers of apoptotic macrophages and reduced lesional collagen compared to sham-treated mice. Intima media thickening of the carotid arteries was also exacerbated. Exposure to (56)Fe ions can therefore accelerate the development of atherosclerotic lesions and promote their progression to an advanced stage characterized by compositional changes indicative of increased thrombogenicity and instability. We conclude that the potential consequences of radiation exposure for astronauts on prolonged deep-space missions are a major concern. Knowledge gained from further studies with animal models should lead to a better understanding of the pathophysiological effects of accelerated ion radiation to better estimate atherogenic risk and develop appropriate countermeasures to mitigate its damaging effects. PMID:21466380

  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. Eplerenone reduced lesion size in early but not advanced atherosclerosis in apolipoprotein E-deficient mice.

    PubMed

    Raz-Pasteur, Ayelet; Gamliel-Lazarovich, Aviva; Coleman, Raymond; Keidar, Shlomo

    2012-12-01

    The beneficial effects of eplerenone, a specific mineralocorticoid receptor blocker, were previously demonstrated in early atherosclerosis (ATS). The aim of the present study was to evaluate the effect of eplerenone in advanced versus early ATS. Apolipoprotein E knockout mice aged 16 or 32 weeks were randomly divided into eplerenone (100 mg·kg·d) or vehicle treatment for 14 weeks. Eplerenone reduced atherosclerotic lesion size by 51% only in early ATS. In peritoneal macrophages obtained from these mice, eplerenone reduced messenger RNA expression of pro-inflammatory markers, interleukin 6, tumor necrosis factor α, monocyte chemotactic protein 1, and increased anti-inflammatory marker arginase 1 to a greater extent in early compared with advanced ATS. These changes correspond to macrophage polarization toward alternative inflammatory phenotype. Messenger RNA expression of the mineralocorticoid receptor and aldosterone synthase were also reduced by eplerenone to a greater extent in early ATS, and these might increase the sensitivity of macrophages to mineralocorticoid blockade in early ATS. The results of the present study point to the benefits of early initiation of treatment with eplerenone in reducing experimental ATS.

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

    PubMed Central

    1988-01-01

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

  15. 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

  16. Abolished synthesis of cholic acid reduces atherosclerotic development in apolipoprotein E knockout mice.

    PubMed

    Slätis, Katharina; Gåfvels, Mats; Kannisto, Kristina; Ovchinnikova, Olga; Paulsson-Berne, Gabrielle; Parini, Paolo; Jiang, Zhao-Yan; Eggertsen, Gösta

    2010-11-01

    To investigate the effects of abolished cholic acid (CA) synthesis in the ApoE knockout model [apolipoprotein E (apoE) KO],a double-knockout (DKO) mouse model was created by crossbreeding Cyp8b1 knockout mice (Cyp8b1 KO), unable to synthesize the primary bile acid CA, with apoE KO mice. After 5 months of cholesterol feeding, the development of atherosclerotic plaques in the proximal aorta was 50% less in the DKO mice compared with the apoE KO mice. This effect was associated with reduced intestinal cholesterol absorption, decreased levels of apoB-containing lipoproteins in the plasma, enhanced bile acid synthesis, reduced hepatic cholesteryl esters, and decreased hepatic activity of ACAT2. The upregulation of Cyp7a1 in DKO mice seemed primarily caused by reduced expression of the intestinal peptide FGF15. Treatment of DKO mice with the farnesoid X receptor (FXR) agonist GW4064 did not alter the intestinal cholesterol absorption, suggesting that the action of CA in this process is confined mainly to formation of intraluminal micelles and less to its ability to activate the nuclear receptor FXR. Inhibition of CA synthesis may offer a therapeutic strategy for the treatment of hyperlipidemic conditions that lead to atherosclerosis.

  17. Apolipoprotein E e4 allele is associated with more rapid motor decline in older persons.

    PubMed

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

    2009-01-01

    We tested the hypothesis that apolipoprotein E allele status predicts the rate of motor decline in the elderly. Eight hundred seventy-six older participants without dementia underwent baseline and annual motor testing for up to 10 years. In a generalized estimating equation controlling for age, sex, and education, motor function declined by about 0.03 U/y. The presence of epsilon4 allele was associated with a 2-fold increase in rate of motor decline epsilon4 allele x time: estimate=-0.027 (SE 0.012, P=0.025)]. The association of epsilon4 allele with motor decline persisted even after controlling for cognitive status, race, body mass index, vascular risk factors, and diseases. Further analyses suggested that the association of epsilon4 with motor decline was for the most part explained by the association between epsilon4 allele and change in muscle strength. These results suggest that the presence of epsilon4 allele is a risk factor for more rapid motor decline in the elderly.

  18. Is apolipoprotein E4 an important risk factor for vascular dementia?

    PubMed

    Rohn, Troy T

    2014-01-01

    Despite the fact that vascular dementia (VaD) represents the seconding leading cause of dementia in the USA, behind only Alzheimer's disease (AD), there remains a lack of consensus on the pathological criteria required for diagnosis of this disease. A number of clinical diagnostic criteria exist but are poorly validated and inconsistently applied. It is clear that vascular risk factors play an important role in the etiology of VaD, including hypertension, stroke, diabetes, and atherosclerosis. Vascular risk factors may increase the risk for VaD by promoting inflammation, cerebral vascular disease, white matter lesions, and hippocampal sclerosis. Because vascular risk factors seem to impart a high degree of risk for conferring VaD, it seems logical that the apolipoprotein E (APOE) status of individuals may be important. APOE plays a critical role in transporting cholesterol in and out of the CNS and in AD it is known that harboring the APOE allele increases the risk of AD perhaps due to the improper functioning of this protein. The purpose of this review is to examine the important pathological features and risk factors for VaD and to provide a critical assessment of the current literature regarding whether or not apoE4 also confers disease risk in VaD. The preponderance of data suggests that harboring one or both APOE4 alleles elevates the risk for VaD, but not to the same extent as found in AD.

  19. 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.

  20. Apolipoprotein E4 genotype does not increase risk of HIV-associated neurocognitive disorders.

    PubMed

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

    2013-04-01

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

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

    PubMed

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

    2008-12-26

    Oxidative stress is implicated in atherogenesis; however most clinical trials with dietary antioxidants failed to show marked success in preventing atherosclerotic diseases. We have found that hydrogen (dihydrogen; H(2)) acts as an effective antioxidant to reduce oxidative stress [I. Ohsawa, M. Ishikawa, K. Takahashi, M. Watanabe, K. Nishimaki, K. Yamagata, K. Katsura, Y. Katayama, S, Asoh, S. Ohta, Hydrogen acts as a therapeutic antioxidant by selectively reducing cytotoxic oxygen radicals, Nat. Med. 13 (2007) 688-694]. Here, we investigated whether drinking H(2)-dissolved water at a saturated level (H(2)-water) ad libitum prevents arteriosclerosis using an apolipoprotein E knockout mouse (apoE(-/-)), a model of the spontaneous development of atherosclerosis. ApoE(-/-) mice drank H(2)-water ad libitum from 2 to 6 month old throughout the whole period. Atherosclerotic lesions were significantly reduced by ad libitum drinking of H(2)-water (p=0.0069) as judged by Oil-Red-O staining series of sections of aorta. The oxidative stress level of aorta was decreased. Accumulation of macrophages in atherosclerotic lesions was confirmed. Thus, consumption of H(2)-dissolved water has the potential to prevent arteriosclerosis. PMID:18996093

  2. 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.

  3. 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

  4. 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

  5. Proteomic analysis of liver mitochondria of apolipoprotein E knockout mice treated with metformin.

    PubMed

    Stachowicz, Aneta; Suski, Maciej; Olszanecki, Rafał; Madej, Józef; Okoń, Krzysztof; Korbut, Ryszard

    2012-12-21

    Nonalcoholic fatty liver disease (NAFLD) is strongly associated with insulin resistance. Metformin, a widely known anti-diabetic drug, used for patients with type 2 diabetes mellitus, is also claimed to be useful in treatment of NAFLD. However, both the clinical efficacy and the putative mechanisms underlying the clinical effects of metformin in treating NAFLD are unclear. Adenosine monophosphate-activated protein kinase (AMPK), the primary molecular target for metformin, is a known regulator of mitochondrial function. Thus, we used a proteomic approach to investigate the effect of metformin on liver mitochondria of apolipoprotein E knockout (apoE(-/-)) mice, an animal model of NAFLD. Two-dimensional electrophoresis coupled with mass spectrometry was applied to study the changes in liver mitochondrial protein expression in 6-month old metformin-treated apoE(-/-) mice as compared to non-treated animals. Collectively, 25 differentially expressed proteins were indentified upon metformin treatment including proteins related to metabolism, oxidative stress and cellular respiration. The most up-regulated protein was glycine N-methyltransferase (GNMT) - an enzyme, whose deficiency was shown to be directly related to the development of NAFLD. Our results clearly point to the strong mitochondrial action of metformin in NAFLD. Up-regulation of GNMT may represent an important mechanism of beneficial action of metformin in NAFLD treatment.

  6. 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

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

    PubMed

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

    2014-09-01

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

  8. Apolipoprotein E genotype predicts 24-month bayley scales infant development score.

    PubMed

    Wright, Robert O; Hu, Howard; Silverman, Edwin K; Tsaih, Shirng W; Schwartz, Joel; Bellinger, David; Palazuelos, Eduardo; Weiss, Scott T; Hernandez-Avila, Mauricio

    2003-12-01

    Apolipoprotein E (APOE) regulates cholesterol and fatty acid metabolism, and may mediate synaptogenesis during neurodevelopment. To our knowledge, the effects of APOE4 isoforms on infant development have not been studied. This study was nested within a cohort of mother-infant pairs living in and around Mexico City. A multiple linear regression model was constructed using the 24-mo Mental Development Index (MDI) of the Bayley Scale as the primary outcome and infant APOE genotype as the primary risk factor of interest. Regression models stratified on APOE genotype were constructed to explore effect modification. Of 311 subjects, 53 (17%) carried at least one copy of the APOE4 allele. Mean (SD) MDI scores among carriers with at least one copy of APOE4 were 94.1 (14.3) and among E3/E2 carriers were 91.2 (14.0). After adjustment for covariates, APOE4 carrier status was associated with a 4.4 point (95% confidence interval: 0.1-8.7; p = 0.04) higher 24-mo MDI. In the stratified regression models, the negative effects for umbilical cord blood lead level on 24-mo MDI score was approximately 4-fold greater among APOE3/APOE2 carriers than among APOE4 carriers. These results suggest that subjects with the E4 isoform of APOE may have advantages over those with the E2 or E3 isoforms with respect to early life neuronal/brain development.

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

    PubMed Central

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

    2014-01-01

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

  10. 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

  11. Gestational hyperlipidemia and acute pancreatitis with underlying partial lipoprotein lipase deficiency and apolipoprotein E3/E2 genotype

    PubMed Central

    Han, Dong Hee; Moh, In Ho; Kim, Doo-Man; Ihm, Sung Hee; Choi, Moon-Gi; Yoo, Hyung Joon

    2013-01-01

    We report the case of a patient who experienced extreme recurrent gestational hyperlipidemia. She was diagnosed with partial lipoprotein lipase (LPL) deficiency but without an associated LPL gene mutation in the presence of the apolipoprotein E3/2 genotype. This is the first reported case of extreme gestational hyperlipidemia with a partial LPL deficiency in the absence of an LPL gene mutation and the apolipoprotein E 3/2 genotype. She was managed with strict dietary control and medicated with omega-3 acid ethyl esters. A patient with extreme hyperlipidemia that is limited to the gestational period should be considered partially LPL-deficient. Extreme instances of hyperlipidemia increase the risk of acute pancreatitis, and the effect of parturition on declining plasma lipid levels can be immediate and dramatic. Therefore, decisions regarding the timing and route of delivery with extreme gestational hyperlipidemia are critical and should be made carefully. PMID:24009459

  12. 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

  13. 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.

  14. 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.

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

    PubMed Central

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

    2015-01-01

    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

  16. 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

  17. Benzo[a]pyrene potentiates the pathogenesis of abdominal aortic aneurysms in apolipoprotein E knockout mice.

    PubMed

    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.

  18. Anti-atherogenic effect of Humulus japonicus in apolipoprotein E-deficient mice

    PubMed Central

    Lim, Haian; Noh, Jung-Ran; Kim, Yong-Hoon; Hwang, Jung Hwan; Kim, Kyoung-Shim; Choi, Dong-Hee; Go, Min-Jeong; Han, Sang-Seop; Oh, Won-Keun; Lee, Chul-Ho

    2016-01-01

    Humulus japonicus (HJ) is used as a traditional medicine in Korea owing to its multiple properties including anti-mycobacterial, antioxidant and antihypertensive effects. The present study aimed to examine the anti-inflammatory and anti-atherogenic effects of a methanol extract of HJ. In lipopolysaccharide-stimulated RAW 264.7 cells, HJ significantly suppressed the mRNA expression and secretion of pro-inflammatory cytokines [tumor necrosis factor-α, interleukin (IL)-1β and IL-6)], and the release of inflammatory mediators such as nitrite and prostaglandin E2, together with a concomitant decrease in the mRNA levels of inducible nitric oxide synthase and cyclooxygenase-2. To examine whether HJ is capable of inhibiting experimental atherogenesis in an animal model, we randomly divided apolipoprotein E-deficient (apoE−/−) mice into three groups: mice fed an atherogenic diet plus vehicle (0.5% carboxymethyl cellulose) as the control vehicle group, and mice fed an atherogenic diet plus either 100 (HJ100) or 500 mg/kg (HJ500) of HJ as the experimental groups. After 12 weeks of HJ administration, lipid accumulation and the formation of atherosclerotic lesions in the aorta (en face) and the aortic sinus markedly decreased in the HJ500 group compared with the corresponding values in the vehicle control group. Moreover, monocyte and macrophage infiltration in the aortic sinus was markedly reduced in the HJ500 group. Reverse transcription-quantitative polymerase chain reaction analysis of the whole aorta showed that the mRNA levels of intercellular adhesion molecule-1, monocyte chemoattractant protein-1, CD68 and IL-18 were significantly decreased in the HJ500 group. Collectively, these findings suggest that HJ may suppress atherosclerosis by inhibiting lipid accumulation and the expression of pro-atherogenic factors, and it may be effective at preventing the development of atherosclerosis. PMID:27600281

  19. Apolipoprotein E-epsilon 4 allele and familial risk in Alzheimer's disease.

    PubMed

    Li, G; Silverman, J M; Altstiel, L D; Haroutunian, V; Perl, D P; Purohit, D; Birstein, S; Lantz, M; Mohs, R C; Davis, K L

    1996-01-01

    Recent studies have found an association between presence of apolipoprotein E (APOE) epsilon 4 allele and Alzheimer's disease (AD). The present study compared the cumulative risk of primary progressive dementia (PPD) in relatives of AD probands carrying at least one copy of the epsilon 4 allele with the relatives of AD probands not carrying epsilon 4 and with relatives of non-demented controls. Our aim was to determine whether the familial aggregation of PPD in relatives of AD probands is primarily due to those carrying epsilon 4. Seventy-seven neuropathologically diagnosed AD patients were obtained as probands through our Alzheimer's Disease Research Center Brain Bank. AD probands were genotyped for APOE. As a comparison group, 198 non-demented probands were also included. Through family informants, demographic and diagnostic data were collected on 382 first-degree relatives (age > or = 45 years) of AD probands and 848 relatives of the controls. We found that the cumulative risk of PPD in both relatives of AD probands with and without the epsilon 4 allele was significantly higher than that in the relatives of non-demented controls. However, the increased risk in the relatives of AD probands with the epsilon 4 allele was marginally, but not significantly, lower than the risk in the relatives of probands without epsilon 4. A greater likelihood of death by heart diseases over developing PPD in relatives of AD probands with epsilon 4 (3.1-fold increase) was found compared to relatives of probands without epsilon 4 (1.7-fold increase), especially prior to age 70, although the difference was not statistically significant. The increased familial risk for PPD in the relatives of AD probands with the APOE-epsilon 4 allele relative to controls suggests that familial factors in addition to APOE-epsilon 4 are risk factors for AD. Differential censorship from increased mortality of heart diseases may have prevented a higher incidence of PPD among the relatives of probands with

  20. Anti-atherogenic effect of Humulus japonicus in apolipoprotein E-deficient mice.

    PubMed

    Lim, Haian; Noh, Jung-Ran; Kim, Yong-Hoon; Hwang, Jung Hwan; Kim, Kyoung-Shim; Choi, Dong-Hee; Go, Min-Jeong; Han, Sang-Seop; Oh, Won-Keun; Lee, Chul-Ho

    2016-10-01

    Humulus japonicus (HJ) is used as a traditional medicine in Korea owing to its multiple properties including anti-mycobacterial, antioxidant and antihypertensive effects. The present study aimed to examine the anti‑inflammatory and anti-atherogenic effects of a methanol extract of HJ. In lipopolysaccharide-stimulated RAW 264.7 cells, HJ significantly suppressed the mRNA expression and secretion of pro-inflammatory cytokines [tumor necrosis factor-α, interleukin (IL)-1β and IL-6)], and the release of inflammatory mediators such as nitrite and prostaglandin E2, together with a concomitant decrease in the mRNA levels of inducible nitric oxide synthase and cyclooxygenase-2. To examine whether HJ is capable of inhibiting experimental atherogenesis in an animal model, we randomly divided apolipoprotein E-deficient (apoE-/-) mice into three groups: mice fed an atherogenic diet plus vehicle (0.5% carboxymethyl cellulose) as the control vehicle group, and mice fed an atherogenic diet plus either 100 (HJ100) or 500 mg/kg (HJ500) of HJ as the experimental groups. After 12 weeks of HJ administration, lipid accumulation and the formation of atherosclerotic lesions in the aorta (en face) and the aortic sinus markedly decreased in the HJ500 group compared with the corresponding values in the vehicle control group. Moreover, monocyte and macrophage infiltration in the aortic sinus was markedly reduced in the HJ500 group. Reverse transcription-quantitative polymerase chain reaction analysis of the whole aorta showed that the mRNA levels of intercellular adhesion molecule-1, monocyte chemoattractant protein-1, CD68 and IL-18 were significantly decreased in the HJ500 group. Collectively, these findings suggest that HJ may suppress atherosclerosis by inhibiting lipid accumulation and the expression of pro-atherogenic factors, and it may be effective at preventing the development of atherosclerosis.

  1. Anti-atherogenic effect of Humulus japonicus in apolipoprotein E-deficient mice.

    PubMed

    Lim, Haian; Noh, Jung-Ran; Kim, Yong-Hoon; Hwang, Jung Hwan; Kim, Kyoung-Shim; Choi, Dong-Hee; Go, Min-Jeong; Han, Sang-Seop; Oh, Won-Keun; Lee, Chul-Ho

    2016-10-01

    Humulus japonicus (HJ) is used as a traditional medicine in Korea owing to its multiple properties including anti-mycobacterial, antioxidant and antihypertensive effects. The present study aimed to examine the anti‑inflammatory and anti-atherogenic effects of a methanol extract of HJ. In lipopolysaccharide-stimulated RAW 264.7 cells, HJ significantly suppressed the mRNA expression and secretion of pro-inflammatory cytokines [tumor necrosis factor-α, interleukin (IL)-1β and IL-6)], and the release of inflammatory mediators such as nitrite and prostaglandin E2, together with a concomitant decrease in the mRNA levels of inducible nitric oxide synthase and cyclooxygenase-2. To examine whether HJ is capable of inhibiting experimental atherogenesis in an animal model, we randomly divided apolipoprotein E-deficient (apoE-/-) mice into three groups: mice fed an atherogenic diet plus vehicle (0.5% carboxymethyl cellulose) as the control vehicle group, and mice fed an atherogenic diet plus either 100 (HJ100) or 500 mg/kg (HJ500) of HJ as the experimental groups. After 12 weeks of HJ administration, lipid accumulation and the formation of atherosclerotic lesions in the aorta (en face) and the aortic sinus markedly decreased in the HJ500 group compared with the corresponding values in the vehicle control group. Moreover, monocyte and macrophage infiltration in the aortic sinus was markedly reduced in the HJ500 group. Reverse transcription-quantitative polymerase chain reaction analysis of the whole aorta showed that the mRNA levels of intercellular adhesion molecule-1, monocyte chemoattractant protein-1, CD68 and IL-18 were significantly decreased in the HJ500 group. Collectively, these findings suggest that HJ may suppress atherosclerosis by inhibiting lipid accumulation and the expression of pro-atherogenic factors, and it may be effective at preventing the development of atherosclerosis. PMID:27600281

  2. 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

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. High serum apolipoprotein E determines hypertriglyceridemic dyslipidemias, coronary disease and apoA-I dysfunctionality.

    PubMed

    Onat, Altan; Can, Günay; Ornek, Ender; Ayhan, Erkan; Erginel-Ünaltuna, Nihan; Murat, Sani N

    2013-01-01

    The relevance of serum apolipoprotein E (apoE) levels to two hypertriglyceridemic dyslipidemias has not been clarified. We explored, in a cross-sectional (and short-term prospective) evaluation, the independent relationship of serum apoE to the atherogenic dyslipidemia, hypertriglyceridemia with elevated apoB (HtgB) and to apoA-I dysfunctionality, previously shown in Turkish adults to be independent of apoE genotype. Serum apoE concentrations were measured by immunonephelometry in 1,127 middle-aged adults. In multivariable regression analysis, apoE concentrations showed log-linear associations with apoB and apoA-I levels, waist circumference, independent of C-reactive protein (CRP), homeostatic model assessment (HOMA) index and other confounders. The likelihood of atherogenic dyslipidemia and of HtgB roughly tripled per 1-SD increment in apoE concentrations, additively to apoE genotype, HOMA, apoA-I, CRP concentrations and waist circumference; yet apoA-I, protective against atherogenic dyslipidemia, appeared to promote HtgB, a finding consistent with apoA-I dysfunctionality in this setting. Each 1-SD increment in the apoE level was moreover, associated in both genders with MetS (at OR 1.5), after adjustment for sex, age, apoB, apoA-I and CRP, or for apoE genotypes. Circulating apoE predicted in both genders age-adjusted prevalent and incident coronary heart disease (CHD), independent of apoE genotype and CRP (OR 1.32 [95 % CI 1.11; 1.58]). To conclude, in a general population prone to MetS, elevated apoE concentrations are strongly linked to HtgB and atherogenic dyslipidemia, irrespective of apoE genotype, are associated with MetS and CHD. Excess apoE reflects pro-inflammatory state and likely autoimmune activation.

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

    PubMed

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

    2013-02-27

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

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

    PubMed

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

    2007-10-01

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

  13. Distinct apolipoprotein E isoform preference for inhibition of smooth muscle cell migration and proliferation.

    PubMed

    Zeleny, Michelle; Swertfeger, Debi K; Weisgraber, Karl H; Hui, David Y

    2002-10-01

    The current study compared the effectiveness of the various human apolipoprotein E (apoE) isoforms in inhibiting platelet-derived growth factor- (PDGF-) stimulated smooth muscle cell proliferation and migration. The incubation of primary mouse aortic smooth muscle cells with apoE3 resulted in dose-dependent inhibition of smooth muscle cells stimulated by 10 ng/mL PDGF. Greater than 50% inhibition of smooth muscle cell proliferation was observed at 15 microg/mL of human apoE3. Human apoE2 was less effective, requiring a higher concentration to achieve inhibition comparable to that of apoE3. Human apoE4 was the least effective of the apoE isoforms with no significant inhibition of cell proliferation observed at concentrations up to 15 microg/mL. Interestingly, apoE inhibition of PDGF-directed smooth muscle cell migration did not show preference for any apoE isoforms. Human apoE2, apoE3, and apoE4 were equally effective in inhibiting smooth muscle cell migration toward PDGF. These results are consistent with previous data showing that apoE inhibition of smooth muscle cell proliferation is mediated through its binding to heparan sulfate proteoglycans, whereas its inhibition of cell migration is mediated via binding to the low-density lipoprotein receptor related protein. The low efficiency of apoE4 to inhibit smooth muscle cell proliferation also suggested another mechanism to explain the association between the apolipoprotein epsilon4 allele with increased risk of coronary artery disease. PMID:12269825

  14. 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.

  15. The effect of apolipoprotein E4 on synchronous neural interactions in brain cultures.

    PubMed

    Christopoulos, Vassilios; Georgopoulos, Angeliki; Georgopoulos, Apostolos P

    2015-06-01

    In a previous study, we assessed the synchronous neural interactions (SNI) in a developing neural network in brain cultures on multielectrode arrays (Christopoulos et al. in J Neural Eng 9:046008, 2012). Here, we report on the effects of apolipoprotein E4 (apoE4) on these neural interactions. We carried out six experiments (five using rodent brain cultures and one using neuroblastoma cultures) in which we recorded local field potentials (LFP) from 59 sites for several days in vitro under the following conditions. In one experiment, we added to the culture media triglyceride (TG)-rich lipoproteins from a human subject with the apoE4/4 genotype, whereas in the other experiments, we added recombinant human apoE4. We found that SNI in the apoE4-treated cultures had higher coefficient of SNI variation, as compared to control cultures. These findings further document the role of SNI as a fundamental aspect of the dynamic organization of neural networks (Langheim et al. in Proc Natl Acad Sci USA 103:455-459, 2006. doi: 10.1073/pnas.0509623102 ; Georgopoulos et al. in J Neural Eng 4:349-355, 2007) and extend the effect of apoE4 on SNI (Leuthold et al. in Exp Brain Res 226:525-536, 2013) across different brain species (human, rodents), apoE source (TG-rich lipoproteins, recombinant), neural signals (MEG, LFP), and brain network (intact brain, developing brain in vitro). To our knowledge, this is the first study of the effects of apoE4 on neural network function in vitro.

  16. Small molecule structure correctors abolish detrimental effects of apolipoprotein E4 in cultured neurons.

    PubMed

    Chen, Hung-Kai; Liu, Zhaoping; Meyer-Franke, Anke; Brodbeck, Jens; Miranda, Rene D; McGuire, James G; Pleiss, Michael A; Ji, Zhong-Sheng; Balestra, Maureen E; Walker, David W; Xu, Qin; Jeong, Dah-eun; Budamagunta, Madhu S; Voss, John C; Freedman, Stephen B; Weisgraber, Karl H; Huang, Yadong; Mahley, Robert W

    2012-02-17

    Apolipoprotein E4 (apoE4), the major genetic risk factor for late onset Alzheimer disease, assumes a pathological conformation, intramolecular domain interaction. ApoE4 domain interaction mediates the detrimental effects of apoE4, including decreased mitochondrial cytochrome c oxidase subunit 1 levels, reduced mitochondrial motility, and reduced neurite outgrowth in vitro. Mutant apoE4 (apoE4-R61T) lacks domain interaction, behaves like apoE3, and does not cause detrimental effects. To identify small molecules that inhibit domain interaction (i.e. structure correctors) and reverse the apoE4 detrimental effects, we established a high throughput cell-based FRET primary assay that determines apoE4 domain interaction and secondary cell- and function-based assays. Screening a ChemBridge library with the FRET assay identified CB9032258 (a phthalazinone derivative), which inhibits domain interaction in neuronal cells. In secondary functional assays, CB9032258 restored mitochondrial cytochrome c oxidase subunit 1 levels and rescued impairments of mitochondrial motility and neurite outgrowth in apoE4-expressing neuronal cells. These benefits were apoE4-specific and dose-dependent. Modifying CB9032258 yielded well defined structure-activity relationships and more active compounds with enhanced potencies in the FRET assay (IC(50) of 23 and 116 nm, respectively). These compounds efficiently restored functional activities of apoE4-expressing cells in secondary assays. An EPR binding assay showed that the apoE4 structure correction resulted from direct interaction of a phthalazinone. With these data, a six-feature pharmacophore model was constructed for future drug design. Our results serve as a proof of concept that pharmacological intervention with apoE4 structure correctors negates apoE4 detrimental effects in neuronal cells and could be further developed as an Alzheimer disease therapeutic.

  17. 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.

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

    PubMed

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

    2014-01-31

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

  19. 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

  20. 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

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

    PubMed

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

    2010-09-01

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

  2. 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.

  3. Frequency and effects of apolipoprotein E polymorphism in Mexican-American NIDDM subjects.

    PubMed

    Shriver, M D; Boerwinkle, E; Hewett-Emmett, D; Hanis, C L

    1991-03-01

    We typed 254 non-insulin-dependent diabetic (NIDDM) Mexican Americans living in Starr County, Texas, for the three common apolipoprotein E (apoE) alleles. Typing was performed via DNA amplification and Hha I restriction. The allele frequencies (epsilon 2 = 0.041, epsilon 3 = 0.860, epsilon 4 = 0.099) were in Hardy-Weinberg equilibrium (chi 2 = 0.60, df = 3) and did not differ from a random sample from the same population (chi 2 = 0.16, df = 2). Analysis of variance was used to test for mean differences in lipid, lipoprotein, and glucose levels among apoE types. Significant differences among types were detected for low-density lipoprotein cholesterol (LDL-chol; P = 0.042, R2 = 2.6) and beta-lipoprotein cholesterol (P = 0.019, R2 = 3.3) levels. Mean LDL-chol in E2/3 individuals was 2.69 mM, E3/3 was 3.26 mM, and E4/3 was 3.36 mM. Mean beta-lipoprotein cholesterol in E2/3 individuals was 3.05 mM, E3/3 was 3.64 mM, and E4/3 was 3.67 mM. Based on these results, we conclude that the effects of the apoE polymorphism on lipid profiles and glucose levels are the same in NIDDM subjects as in nondiabetic Mexican Americans and other populations. Other studies investigating the role of apoE polymorphism in diabetic subjects have found increased triglyceride levels in individuals possessing an epsilon 2-allele and an increased frequency of the epsilon 2-allele in hyperlipidemic diabetic subjects. We found no significant difference in mean triglyceride levels among genotypes. Possible reasons for this discrepancy are discussed, including DNA- versus protein-typing methods. PMID:1999275

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2016-08-01

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

  6. 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

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

    PubMed

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

    2004-11-01

    The effect on the electrochemical oxidation and reduction potentials of 5,10,15,20-tetrakis(benzo-15-crown-5)porphyrin (TCP) and its metal derivatives (MTCP; M = Mg(II), VO(IV), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Ag(II)) upon potassium ion induced dimerization of the porphyrins was systematically performed in benzonitrile containing 0.1 M (TBA)ClO(4) by differential pulse voltammetry technique. The HOMO--LUMO energy level diagram constructed from the electrochemical data revealed destabilization of the HOMO level and stabilization of the LUMO level upon dimer formation while such a perturbation was larger for the HOMO level than the LUMO level. The geometry and electronic structure of a representative ZnTCP and its dimer, K(4)(ZnTCP)(2), were evaluated by the ab initio B3LYP method utilizing a mixed basis set of 3-21G(*) for Zn, K, O, and N and STO-3G for C and H. The inter-porphyrin ring distance of the dimer calculated from the optimized geometry agreed with the spectroscopically determined one, and the calculated HOMO and LUMO frontier orbitals revealed delocalization on both of the porphyrins rings. The metal-metal distances calculated from the triplet ESR spectra of the K(+) induced porphyrin dimers bearing paramagnetic metal ions in the cavity followed the trend Cu--Cu < VO--VO < Ag--Ag. However, the spectral shifts resulting from the exciton coupling of the interacting porphyrin pi-systems revealed no specific trend with respect to the metal ion in the porphyrin cavity. Additionally, linear trends in the electrochemically measured HOMO--LUMO gap and the energy corresponding to the most intense visible band of both MTCP and K(4)(MTCP)(2) were observed. A reduced HOMO--LUMO gap predicted for the dimer by B3LYP/(3-21G(), STO-3G) calculations was confirmed by the results of optical absorption and electrochemical studies. PMID:15500335

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

    SciTech Connect

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

    2009-06-04

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

  9. 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

  10. 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

  11. 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

  12. Apolipoprotein E-related all-cause mortality in hospitalized elderly patients.

    PubMed

    Matera, Maria G; Sancarlo, Daniele; Panza, Francesco; Gravina, Carolina; D'Onofrio, Grazia; Frisardi, Vincenza; Longo, Grazia; D'Ambrosio, Luigi P; Addante, Filomena; Copetti, Massimiliano; Solfrizzi, Vincenzo; Seripa, Davide; Pilotto, Alberto

    2010-09-01

    The most common apolipoprotein E (APOE) allelic variation is implicated in many age-related diseases and human longevity with controversial findings. We investigated the effect of APOE gene polymorphism on all-cause mortality in elderly patients taking into consideration the functional disability, cognitive impairment, malnutrition, and the occurrence of common age-related diseases. APOE genotypes were determined in 2,124 geriatric hospitalized patients (46.5% men and 53.5% women; mean age, 78.2 +/- 7.1 years; range, 65-100 years). At hospital admission, all patients underwent a comprehensive geriatric assessment to evaluate functional disability, cognitive status, nutritional status, and comorbidity. The main and secondary diagnoses at hospital discharge were also recorded. Mortality status was evaluated in all patients after a maximum follow-up of 5 years (range, from 1.26 to 5.23 years; median, 2.86 years). During the study period, 671 patients died (32.0%). At hospital admission, these patients showed a significant higher prevalence of cardiovascular diseases (56.3% vs 53.4%; p = 0.007), neoplasias (32.3% vs 13.7%; p < 0.001), and lower prevalence of neurodegenerative diseases (17.7% vs 20.7%; p < 0.001) than survived patients. Moreover, they also showed an higher prevalence of disability (52.0% vs 25.6%; p < 0.001), cognitive impairment (31.0% vs 18.8%; p < 0.001), and malnutrition (74.0% vs 46.1%; p < 0.001) than survived patients. In the overall study population, the APOE epsilon2 allele was significantly associated to neurodegenerative diseases (odds ratio = 0.59; 95% confidence interval (CI), 0.37-0.94). No significant association between the APOE polymorphism and disability, malnutrition, co-morbidity status, and with all-cause mortality was observed. In patients with cardiovascular diseases, however, a decreased risk of all-cause mortality was found in the epsilon2 allele carriers (hazard ratio = 0.56; 95% CI, 0.36-0.88). In this population, APOE allele

  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.

  15. Apolipoprotein E Allelic Frequency Altered in Women with Early-onset Breast Cancer.

    PubMed

    Porrata-Doria, Tirtsa; Matta, Jaime L; Acevedo, Summer F

    2010-05-24

    Among women, the most prevalent type of cancer is breast cancer, affecting 1 out of every 8 women in the United States; in Puerto Rico, 70 out of every 100,000 will develop some type of breast cancer. Therefore, a better understand of the potential risk factors for breast cancer could lead to the development of early detection tools. A gene that has been proposed as a risk factor in several populations around the world is Apolipoprotein E (apoE). ApoE functions as a mechanism of transport for lipoproteins and cholesterol throughout the body, with 3 main isoforms present in humans (apoE2, apoE3, and apoE4). Whether or not apoE4 is a risk factor for breast cancer remains controversial. Previous studies have either included test subjects of all ages (20-80) or have focused on late-onset (after age 50) breast cancer; none has concentrated specifically on early-onset (aged 50 and younger) breast cancer. The objectives of this study was to examine (in a Puerto Rican population) the differences in the relative frequency of occurrence of apoE4 in non-breast cancer versus breast cancer patients and to examine, as well, the potential differences of same in early- versus late-onset patients. We found an increased frequency of apoE4 (odds ratio 2.15) only in early-onset breast cancer survivors, which is similar to the findings of those studies that combined or adjusted for age as well as for an association between apoE4 and decreased tumor size. ApoE is also a potential risk factor for long-term cognitive effects after chemotherapy and affects response to hormone replacement. Our data supports the theory that knowing the apoE genotype of women who are at risk of developing breast cancer may be beneficial, as such knowledge would aid in the prediction of tumor size and the development of treatment regimens.

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

    PubMed Central

    Zhao, Wenchen; Shimizu, Yoko; Pfeifer, Tom A.; Tak, Jun-Hyung; Isman, Murray B.; Van den Hoven, Bernard; Duggan, Mark E.; Wood, Michael W.; Wellington, Cheryl L.

    2016-01-01

    The apolipoprotein E (APOE) gene is the most highly associated susceptibility locus for late onset Alzheimer’s Disease (AD), and augmenting the beneficial physiological functions of apoE is a proposed therapeutic strategy. In a high throughput phenotypic screen for small molecules that enhance apoE secretion from human CCF-STTG1 astrocytoma cells, we show the chrysanthemic ester 82879 robustly increases expressed apoE up to 9.4-fold and secreted apoE up to 6-fold and is associated with increased total cholesterol in conditioned media. Compound 82879 is unique as structural analogues, including pyrethroid esters, show no effect on apoE expression or secretion. 82879 also stimulates liver x receptor (LXR) target genes including ATP binding cassette A1 (ABCA1), LXRα and inducible degrader of low density lipoprotein receptor (IDOL) at both mRNA and protein levels. In particular, the lipid transporter ABCA1 was increased by up to 10.6-fold upon 82879 treatment. The findings from CCF-STTG1 cells were confirmed in primary human astrocytes from three donors, where increased apoE and ABCA1 was observed along with elevated secretion of high-density lipoprotein (HDL)-like apoE particles. Nuclear receptor transactivation assays revealed modest direct LXR agonism by compound 82879, yet 10 μM of 82879 significantly upregulated apoE mRNA in mouse embryonic fibroblasts (MEFs) depleted of both LXRα and LXRβ, demonstrating that 82879 can also induce apoE expression independent of LXR transactivation. By contrast, deletion of LXRs in MEFs completely blocked mRNA changes in ABCA1 even at 10 μM of 82879, indicating the ability of 82879 to stimulate ABCA1 expression is entirely dependent on LXR transactivation. Taken together, compound 82879 is a novel chrysanthemic ester capable of modulating apoE secretion as well as apoE-associated lipid metabolic pathways in astrocytes, which is structurally and mechanistically distinct from known LXR agonists. PMID:27598782

  17. 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

  18. 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

  19. 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.

  20. 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

  1. The four canonical tpr subunits of human APC/C form related homo-dimeric structures and stack in parallel to form a TPR suprahelix.

    PubMed

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

    2013-11-15

    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 (Cdc23(Nterm)). Cdc23(Nterm) is composed of seven contiguous TPR motifs that self-associate through a related mechanism to those of Cdc16 and Cdc27. Using the Cdc23(Nterm) 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.

  2. 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

  3. Optical tuning of near and far fields form hybrid dimer nanoantennas via laser-induced melting

    NASA Astrophysics Data System (ADS)

    Kolodny, Stanislav A.; Sun, Yali; Zuev, Dmitry A.; Makarov, Sergey V.; Krasnok, Alexander E.; Belov, Pavel A.

    2016-08-01

    Hybrid nanophotonics based on metal-dielectric nanostructures unifies the advantages of plasmonics and all-dielectric nanophotonics providing strong localization of light, magnetic optical response and specifically designed scattering properties. Here, we propose a new method for optical properties tuning of hybrid dimer nanoantenas via laser-induced melting at the nanoscale. We demonstrate numerically that near- and farfield properties of a hybrid nanoantenna dramatically changes with fs-laser modification of Au particle. The results lay the groundwork for the fine-tuning of hybrid nanoantennas and can be applied for effective light manipulation at the nanoscale, as well as biomedical and energy applications.

  4. 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

  5. Thioredoxin A Active-Site Mutants Form Mixed Disulfide Dimers That Resemble Enzyme–Substrate Reaction Intermediates

    PubMed Central

    Kouwen, Thijs R.H.M.; Andréll, Juni; Schrijver, Rianne; Dubois, Jean-Yves F.; Maher, Megan J.; Iwata, So; Carpenter, Elisabeth P.; van Dijl, Jan Maarten

    2008-01-01

    Thioredoxin functions in nearly all organisms as the major thiol–disulfide oxidoreductase within the cytosol. Its prime purpose is to maintain cysteine-containing proteins in the reduced state by converting intramolecular disulfide bonds into dithiols in a disulfide exchange reaction. Thioredoxin has been reported to contribute to a wide variety of physiological functions by interacting with specific sets of substrates in different cell types. To investigate the function of the essential thioredoxin A (TrxA) in the low-GC Gram-positive bacterium Bacillus subtilis, we purified wild-type TrxA and three mutant TrxA proteins that lack either one or both of the two cysteine residues in the CxxC active site. The pure proteins were used for substrate-binding studies known as “mixed disulfide fishing” in which covalent disulfide-bonded reaction intermediates can be visualized. An unprecedented finding is that both active-site cysteine residues can form mixed disulfides with substrate proteins when the other active-site cysteine is absent, but only the N-terminal active-site cysteine forms stable interactions. A second novelty is that both single-cysteine mutant TrxA proteins form stable homodimers due to thiol oxidation of the remaining active-site cysteine residue. To investigate whether these dimers resemble mixed enzyme–substrate disulfides, the structure of the most abundant dimer, C32S, was characterized by X-ray crystallography. This yielded a high-resolution (1.5Å) X-ray crystallographic structure of a thioredoxin homodimer from a low-GC Gram-positive bacterium. The C32S TrxA dimer can be regarded as a mixed disulfide reaction intermediate of thioredoxin, which reveals the diversity of thioredoxin/substrate-binding modes. PMID:18455736

  6. Effect of apolipoprotein E and butyrylcholinesterase genotypes on cognitive response to cholinesterase inhibitor treatment at different stages of Alzheimer's disease.

    PubMed

    Patterson, C E; Todd, S A; Passmore, A P

    2011-12-01

    Factors that influence response to drug treatment are of increasing importance. We report an analysis of genetic factors affecting response to cholinesterase inhibitor therapy in 165 subjects with Alzheimer's disease (AD). The presence of apolipoprotein E ε4 (APOE ε4) allele was associated with early and late cognitive response to cholinesterase inhibitor treatment in mild AD (Mini-Mental State Examination (MMSE) ≥21) (P<0.01). In moderate-to-severe AD (MMSE ≤15), presence of the BCHE-K variant was associated with late response to cholinesterase inhibitor treatment (P=0.02). Testing for APOE and BCHE genotypes may be useful in therapeutic decision making.

  7. 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.

  8. Circulating Apolipoprotein E Concentration and Cardiovascular Disease Risk: Meta-analysis of Results from Three Studies

    PubMed Central

    Sofat, Reecha; Cooper, Jackie A.; Kumari, Meena; Casas, Juan P.; Acharya, Jayshree; Thom, Simon; Humphries, Steve E.; Hingorani, Aroon D.

    2016-01-01

    Background The association of APOE genotype with circulating apolipoprotein E (ApoE) concentration and cardiovascular disease (CVD) risk is well established. However, the relationship of circulating ApoE concentration and CVD has received little attention. Methods and Findings To address this, we measured circulating ApoE concentration in 9,587 individuals (with 1,413 CVD events) from three studies with incident CVD events: two population-based studies, the English Longitudinal Study of Ageing (ELSA) and the men-only Northwick Park Heart Study II (NPHSII), and a nested sub-study of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT). We examined the association of circulating ApoE with cardiovascular risk factors in the two population-based studies (ELSA and NPHSII) and the relationship between ApoE concentration and coronary heart disease and stroke in all three studies. Analyses were carried out within study, and, where appropriate, pooled effect estimates were derived using meta-analysis. In the population-based samples, circulating ApoE was associated with systolic blood pressure (correlation coefficient 0.08, p < 0.001, in both ELSA and NPHSII), total cholesterol (correlation coefficient 0.46 and 0.34 in ELSA and NPHSII, respectively; both p < 0.001), low-density lipoprotein cholesterol (correlation coefficient 0.30 and 0.14, respectively; both p < 0.001), high-density lipoprotein (correlation coefficient 0.16 and −0.14, respectively; both p < 0.001), and triglycerides (correlation coefficient 0.43 and 0.46, respectivly; both p < 0.001). In NPHSII, ApoE concentration was additionally associated with apolipoprotein B (correlation coefficient 0.13, p = 0.001) and lipoprotein(a) (correlation coefficient −0.11, p < 0.001). In the pooled analysis of ASCOT, ELSA, and NPHSII, there was no association of ApoE with CVD events; the odds ratio (OR) for CVD events per 1-standard-deviation higher ApoE concentration was 1.02 (95% CI 0.96, 1.09). After adjustment for

  9. Amplification refractory mutation system polymerase chain reaction versus optimized polymerase chain reaction restriction-fragment length polymorphism for apolipoprotein E genotyping of majorly depressed patients.

    PubMed

    You, Hongmin; Chen, Jin; Zhou, Jingjing; Huang, Hua; Pan, Junxi; Wang, Ziye; Lv, Lin; Zhang, Lujun; Li, Juan; Qin, Bin; Yang, Yongtao; Xie, Peng

    2015-11-01

    Major depressive disorder (MDD) is a prevalent, debilitating mood disorder that has been associated with several genetic polymorphisms. One such polymorphism, namely that of apolipoprotein E (APOE), has three allelic forms (ε2, ε3 and ε4) that encode for six unique isoforms of the APOE protein. A growing number of techniques have been developed for APOE genotyping; however, not all polymerase chain reaction (PCR)‑based genotyping techniques are equally accurate or cost‑effective. In order to find a more accurate and cost‑effective APOE genotyping method for MDD screening in large populations, the present study comparatively evaluated two genotyping methods, amplification refractory mutation system PCR (ARMS‑PCR) and optimized PCR restriction‑fragment length polymorphism (PCR‑RFLP), in blood samples taken from a population of 708 MDD patients. Although either of the two methods were able to detect all six unique APOE genotypes, comparisons of the two methods with Sanger sequencing demonstrated that ARMS‑PCR (94%) was significantly more accurate than optimized PCR‑RFLP (82%). ARMS‑PCR should prove useful in quickly verifying ambiguous results obtained by other APOE genotyping methods and can be cost-effectively performed in the setting of a small laboratory or a population-based screening program.

  10. Following activation of the amyloid cascade, apolipoprotein E4 drives the in vivo oligomerization of amyloid-β resulting in neurodegeneration.

    PubMed

    Belinson, Haim; Kariv-Inbal, Zehavit; Kayed, Rakez; Masliah, Eliezer; Michaelson, Daniel M

    2010-01-01

    According to the amyloid hypothesis, the accumulation of oligomerized amyloid-β (Aβ) is a primary event in the pathogenesis of Alzheimer's disease (AD). The trigger of the amyloid cascade and of Aβ oligomerization in sporadic AD, the most prevalent form of the disease, remains elusive. Here, we examined the hypothesis that apolipoprotein E4 (ApoE4), the most prevalent genetic risk factor for AD, triggers the accumulation of intraneuronal oligomerized Aβ following activation of the amyloid cascade. We investigated the intracellular organelles that are targeted by these processes and govern their pathological consequences. This revealed that activation of the amyloid cascade in vivo by inhibition of the Aβ degrading enzyme neprilysin specifically results in accumulation of Aβ and oligomerized Aβ and of ApoE4 in the CA1 neurons of ApoE4 mice. This was accompanied by lysosomal and mitochondrial pathology and the co-localization of Aβ, oligomerized Aβ, and ApoE4 with enlarged lysosomes and of Aβ and oligomerized Aβ with mitochondria. The time course of the lysosomal effects paralleled that of the loss of CA1 neurons, whereas the mitochondrial effects reached an earlier plateau. These findings suggest that ApoE4 potentiates the pathological effects of Aβ and the amyloid cascade by triggering the oligomerization of Aβ, which in turn, impairs intraneuronal mitochondria and lysosomes and drives neurodegeneration.

  11. Following activation of the amyloid cascade, apolipoprotein E4 drives the in vivo oligomerization of amyloid-β resulting in neurodegeneration

    PubMed Central

    Belinson, Haim; Kariv-Inbal, Zehavit; Kayed, Rakez; Masliah, Eliezer; Michaelson, Daniel M.

    2016-01-01

    According to the amyloid hypothesis, the accumulation of oligomerized Aβ is a primary event in the pathogenesis of Alzheimer’s disease (AD). The trigger of the amyloid cascade and of Aβ oligomerization in sporadic AD, the most prevalent form of the disease, remains elusive. Here we examined the hypothesis that apolipoprotein E4 (apoE4), the most prevalent genetic risk factor for AD, triggers the accumulation of intraneuronal oligomerized Aβ following activation of the amyloid cascade. We investigated the intracellular organelles that are targeted by these processes and govern their pathological consequences. This revealed that activation of the amyloid cascade in vivo by inhibition of the Aβ degrading enzyme neprilysin specifically results in accumulation of Aβ and oligomerized Aβ and of apoE4 in CA1 neurons of apoE4 mice. This was accompanied by lysosomal and mitochondrial pathology and the co-localization of Aβ, oligomerized Aβ and apoE4 with enlarged lysosomes and of Aβ and oligomerized Aβ with mitochondria. The time course of the lysosomal effects paralleled that of the loss of CA1 neurons, whereas the mitochondrial effects reached a plateau earlier. These findings suggest that apoE4 potentiates the pathological effects of Aβ and the amyloid cascade by triggering the oligomerization of Aβ, which in turn, impairs intraneuronal mitochondria and lysosomes and drives neurodegeneration. PMID:20858958

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

    Bax is a key regulator of apoptosis that mediates the release of cytochrome c to the cytosol via oligomerization in the outer mitochondrial membrane before pore formation. However, the molecular mechanism of Bax assembly and regulation by other Bcl-2 members remains obscure. Here, by analysing the stoichiometry of Bax oligomers at the single-molecule level, we find that Bax binds to the membrane in a monomeric state and then self-assembles in <1 min. Strikingly, active Bax does not exist in a unique oligomeric state, but as several different species based on dimer units. Moreover, we show that cBid activates Bax without affecting its assembly, while Bcl-xL induces the dissociation of Bax oligomers. On the basis of our experimental data and theoretical modelling, we propose a new mechanism for the molecular pathway of Bax assembly to form the apoptotic pore.

  13. 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

  14. Intrapolypeptide Interactions between the GTPase Effector Domain (GED) and the GTPase Domain Form the Bundle Signaling Element in Dynamin Dimers

    PubMed Central

    2015-01-01

    Biochemical and structural studies of dynamin have shown that the C-terminus of the GTPase effector domain (GED) folds back and docks onto a platform created by the N- and C-terminal α-helices of the GTPase domain to form a three-helix bundle. While cross-linking studies suggested that insect cell-expressed dynamin existed as a domain-swapped dimer, X-ray structures of protein expressed in Escherichia coli failed to detect evidence of this domain swap. Here, by cross-linking several cysteine pair replacements and analyzing cross-linked species by matrix-assisted laser desorption ionization Mega time of flight, we conclude that dynamin is not domain-swapped and that GED–GTPase domain interactions occur in cis. PMID:25171143

  15. 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.

  16. 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.

  17. 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

  18. Altered small-world anatomical networks in Apolipoprotein-E4 (ApoE4) carriers using MRI.

    PubMed

    Goryawala, Mohammed; Zhou, Qi; Duara, Ranjan; Loewenstein, David; Cabrerizo, Mercedes; Barker, Warren; Adjouadi, Malek

    2014-01-01

    Apolipoprotein E (ApoE) gene and primarily its allele e4 have been identified as a risk factor for Alzheimer's disease (AD). The prevalence of the gene in 25-30% in the population makes it essential to estimate its role in neuroregulation and its impact on distributed brain networks. In this study, we provide computational neuroanatomy based interpretation of large-scale and small-world cortical networks in cognitive normal (CN) subjects with differing Apolipoprotein-E4 (ApoE4) gene expression. We estimated large-scale anatomical networks from cortical thickness measurements derived from magnetic resonance imaging in 147 CN subjects explored in relation to ApoE4 genotype (e4+ carriers (n=41) versus e4- non-carriers (n=106)). Brain networks were constructed by thresholding cortical thickness correlation matrices of 68 bilateral regions of the brain analyzed using well-established graph theoretical approaches. Compared to ApoE4 non-carriers, carriers showed increased interregional correlation coefficients in regions like precentral, superior frontal and inferior temporal regions. Interestingly most of the altered connections were intra-hemispheric limited primarily to the right hemisphere. Furthermore, ApoE4 carriers demonstrated abnormal small-world architecture in the cortical networks with increased clustering coefficient and path lengths as compared to non-carrier, suggesting a less optimal topological organization. Additionally non-carriers demonstrated higher betweenness in regions such as middle temporal, para-hippocampal gyrus, posterior cingulate and insula of the default mode network (DMN), also seen in subjects with AD and mild cognitive impairment (MCI). The results suggest that the complex morphological cortical connectivity patterns are altered in ApoE4 carriers as compared to non-carriers, providing evidence for disruption of integrity in large-scale anatomical brain networks.

  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

    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

  1. 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

  2. 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.

  3. 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.…

  4. 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...

  5. Effect of dimer dissociation on activity and thermostability of the alpha-glucuronidase from Geobacillus stearothermophilus: dissecting the different oligomeric forms of family 67 glycoside hydrolases.

    PubMed

    Shallom, Dalia; Golan, Gali; Shoham, Gil; Shoham, Yuval

    2004-10-01

    The oligomeric organization of enzymes plays an important role in many biological processes, such as allosteric regulation, conformational stability and thermal stability. alpha-Glucuronidases are family 67 glycosidases that cleave the alpha-1,2-glycosidic bond between 4-O-methyl-D-glucuronic acid and xylose units as part of an array of hemicellulose-hydrolyzing enzymes. Currently, two crystal structures of alpha-glucuronidases are available, those from Geobacillus stearothermophilus (AguA) and from Cellvibrio japonicus (GlcA67A). Both enzymes are homodimeric, but surprisingly their dimeric organization is different, raising questions regarding the significance of dimerization for the enzymes' activity and stability. Structural comparison of the two enzymes suggests several elements that are responsible for the different dimerization organization. Phylogenetic analysis shows that the alpha-glucuronidases AguA and GlcA67A can be classified into two distinct subfamilies of bacterial alpha-glucuronidases, where the dimer-forming residues of each enzyme are conserved only within its own subfamily. It seems that the different dimeric forms of AguA and GlcA67A represent the two alternative dimeric organizations of these subfamilies. To study the biological significance of the dimerization in alpha-glucuronidases, we have constructed a monomeric form of AguA by mutating three of its interface residues (W328E, R329T, and R665N). The activity of the monomer was significantly lower than the activity of the wild-type dimeric AguA, and the optimal temperature for activity of the monomer was around 35 degrees C, compared to 65 degrees C of the wild-type enzyme. Nevertheless, the melting temperature of the monomeric protein, 72.9 degrees C, was almost identical to that of the wild-type, 73.4 degrees C. It appears that the dimerization of AguA is essential for efficient catalysis and that the dissociation into monomers results in subtle conformational changes in the structure

  6. Effect of Dimer Dissociation on Activity and Thermostability of the α-Glucuronidase from Geobacillus stearothermophilus: Dissecting the Different Oligomeric Forms of Family 67 Glycoside Hydrolases

    PubMed Central

    Shallom, Dalia; Golan, Gali; Shoham, Gil; Shoham, Yuval

    2004-01-01

    The oligomeric organization of enzymes plays an important role in many biological processes, such as allosteric regulation, conformational stability and thermal stability. α-Glucuronidases are family 67 glycosidases that cleave the α-1,2-glycosidic bond between 4-O-methyl-d-glucuronic acid and xylose units as part of an array of hemicellulose-hydrolyzing enzymes. Currently, two crystal structures of α-glucuronidases are available, those from Geobacillus stearothermophilus (AguA) and from Cellvibrio japonicus (GlcA67A). Both enzymes are homodimeric, but surprisingly their dimeric organization is different, raising questions regarding the significance of dimerization for the enzymes' activity and stability. Structural comparison of the two enzymes suggests several elements that are responsible for the different dimerization organization. Phylogenetic analysis shows that the α-glucuronidases AguA and GlcA67A can be classified into two distinct subfamilies of bacterial α-glucuronidases, where the dimer-forming residues of each enzyme are conserved only within its own subfamily. It seems that the different dimeric forms of AguA and GlcA67A represent the two alternative dimeric organizations of these subfamilies. To study the biological significance of the dimerization in α-glucuronidases, we have constructed a monomeric form of AguA by mutating three of its interface residues (W328E, R329T, and R665N). The activity of the monomer was significantly lower than the activity of the wild-type dimeric AguA, and the optimal temperature for activity of the monomer was around 35°C, compared to 65°C of the wild-type enzyme. Nevertheless, the melting temperature of the monomeric protein, 72.9°C, was almost identical to that of the wild-type, 73.4°C. It appears that the dimerization of AguA is essential for efficient catalysis and that the dissociation into monomers results in subtle conformational changes in the structure which indirectly influence the active site region

  7. Engineered humanized dimeric forms of IgG are more effective antibodies

    PubMed Central

    1992-01-01

    Humanized IgG1 M195 (HuG1-M195), a complementarity determining region- grafted recombinant monoclonal antibody, is reactive with CD33, an antigen expressed on myelogenous leukemia cells. M195 is in use in trials for the therapy of acute myelogenous leukemia. Since biological activity of IgG may depend, in part, on multimeric Fab and Fc clustering, homodimeric forms of HuG1-M195 were constructed by introducing a mutation in the gamma 1 chain CH3 region gene to change a serine to a cysteine, allowing interchain disulfide bond formation at the COOH terminal of the IgG. Despite similar avidity, the homodimeric IgG showed a dramatic improvement in the ability to internalize and retain radioisotope in target leukemia cells. Moreover, homodimers were 100-fold more potent at complement-mediated leukemia cell killing and antibody-dependent cellular cytotoxicity using human effectors. Therefore, genetically engineered multimeric constructs of IgG may have advantages relative to those forms that are found naturally. PMID:1402660

  8. 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

  9. 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.

  10. Subunit b-dimer of the Escherichia coli ATP synthase can form left-handed coiled-coils.

    PubMed

    Wise, John G; Vogel, Pia D

    2008-06-01

    One remaining challenge to our understanding of the ATP synthase concerns the dimeric coiled-coil stator subunit b of bacterial synthases. The subunit b-dimer has been implicated in important protein interactions that appear necessary for energy conservation and that may be instrumental in energy conservation during rotary catalysis by the synthase. Understanding the stator structure and its interactions with the rest of the enzyme is crucial to the understanding of the overall catalytic mechanism. Controversy exists on whether subunit b adopts a classic left-handed or a presumed right-handed dimeric coiled-coil and whether or not staggered pairing between nonhomologous residues in the homodimer is required for intersubunit packing. In this study we generated molecular models of the Escherichia coli subunit b-dimer that were based on the well-established heptad-repeat packing exhibited by left-handed, dimeric coiled-coils by employing simulated annealing protocols with structural restraints collected from known structures. In addition, we attempted to create hypothetical right-handed coiled-coil models and left- and right-handed models with staggered packing in the coiled-coil domains. Our analyses suggest that the available structural and biochemical evidence for subunit b can be accommodated by classic left-handed, dimeric coiled-coil quaternary structures.

  11. Conformational and thermal stability of mature dimeric human myeloperoxidase and a recombinant monomeric form from CHO cells.

    PubMed

    Banerjee, Srijib; Stampler, Johanna; Furtmüller, Paul G; Obinger, Christian

    2011-02-01

    Myeloperoxidase (MPO) is a lysosomal heme enzyme present in the azurophilic granules of human neutrophils and monocytes. It is a critical element of the human innate immune system by exerting antimicrobial effects. It is a disulfide bridged dimer with each monomer containing a light and a heavy polypeptide and its biosynthesis and intracellular transport includes several posttranslational processing steps. By contrast, MPO recombinantly produced in Chinese hamster ovary cell lines is monomeric, partially unprocessed and contains a N-terminal propeptide (proMPO). It mirrors a second form of MPO constitutively secreted from normal bone marrow myeloid precursors. In order to clarify the impact of posttranslational modifications on the structural integrity and enzymology of these two forms of human myeloperoxidase, we have undertaken an investigation on the conformational and thermal stability of leukocyte MPO and recombinant proMPO by using complementary biophysical techniques including UV-Vis, circular dichroism and fluorescence spectroscopy as well as differential scanning calorimetry. Mature leucocyte MPO exhibits a peculiar high chemical and thermal stability under oxidizing conditions but is significantly destabilized by addition of dithiothreitol. Unfolding of secondary and tertiary structure occurs concomitantly with denaturation of the heme cavity, reflecting the role of three MPO-typical heme to protein linkages and of six intra-chain disulfides for structural integrity by bridging N- and C-terminal regions of the protein. Recombinant monomeric proMPO follows a similar unfolding pattern but has a lower conformational and thermal stability. Spectroscopic and thermodynamic data of unfolding are discussed with respect to the known three-dimensional structure of leukocyte MPO as well as to known physiological roles. PMID:20933108

  12. The locus for apolipoprotein E (apoE) is close to the Lutheran (Lu) blood group locus on chromosome 19.

    PubMed

    Gedde-Dahl, T; Olaisen, B; Teisberg, P; Wilhelmy, M C; Mevåg, B; Helland, R

    1984-01-01

    Linkage has been described between the loci for apolipoprotein E (apoE) and the complement C3 (C3) on chromosome 19. C3 is known to belong to a linkage group with gene order C3-Se-Lu. The present study revealed linkage between Se and apoE with peak lod score +3.3 at recombination fraction 0.08 in males and +1.36 at 0.22 in females, and linkage between apoE and Lu with lod score +4.52 at zero recombination in sexes combined. The C3-apoE linkage gives lod score +4.00 at theta = 0.18 in males, but +0.04 at theta = 0.45 in females. Triple heterozygote families confirm that apoE is on the Se side and on the Lu side of C3. Allelic association between apoE and Lu has not been ruled out. Combining our data with published data on C3-Se and Se-Lu, this segment of chromosome 19 has an average age sex ratio of female/male recombination of 2.3.

  13. 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

  14. The Apolipoprotein E Polymorphism rs7412 Associates with Body Fatness Independently of Plasma Lipids in Middle Aged Men

    PubMed Central

    Tejedor, M. Teresa; Garcia-Sobreviela, Maria Pilar; Ledesma, Marta; Arbones-Mainar, Jose M.

    2014-01-01

    Background The apolipoprotein E (APOE) gene is polymorphic, encoding one of 3 common alleles (ε2, ε3, ε4) produced from combinations of 2 non-synonymous SNPs (rs429358 and rs7412). APOE plays an important role controlling plasma lipids but its association with adipocyte functionality and body fatness remains to be determined. Methods We analyzed fasting plasma lipids and genotyped the two main APOE-SNPs (rs429358 and rs7412), both located in the fourth exon of the APOE, in 4660 Caucasian middle-aged men free of cardiovascular disease. Results The rs7412 SNP, which determines the APOE2 isoform, was significantly associated with Body Mass Index (BMI) and Waist Girth (WG) in a multivariate model accounting for age, smoking status and plasma lipids. BMI and WG were highest in TT homozygotes and lowest in CC homozygotes. This effect was independent of the rs429358 SNP, which failed to show any association with the BMI and WG variables. The odds ratio of being obese (BMI>30) for individuals carrying the APOε2 allele, present in 14% of the cohort and defined by the rs7412 SNP, was also significant in this multivariate model, with an OR of 1.27 (95% CI: 1.01–1.59). Conclusions This study provides an evidence of a lipid-independent association between the APOE SNP rs7412 and body fatness surrogates, BMI and WG, in a large cohort of middle-aged males. PMID:25268647

  15. Angiopoietin-2 attenuates angiotensin II-induced aortic aneurysm and atherosclerosis in apolipoprotein E-deficient mice

    PubMed Central

    Yu, Hongyou; Moran, Corey S.; Trollope, Alexandra F.; Woodward, Lynn; Kinobe, Robert; Rush, Catherine M.; Golledge, Jonathan

    2016-01-01

    Angiogenesis and inflammation are implicated in aortic aneurysm and atherosclerosis and regulated by angiopoietin-2 (Angpt2). The effect of Angpt2 administration on experimental aortic aneurysm and atherosclerosis was examined. Six-month-old male apolipoprotein E deficient (ApoE−/−) mice were infused with angiotensin II (AngII) and administered subcutaneous human Fc-protein (control) or recombinant Angpt2 (rAngpt2) over 14 days. Administration of rAngpt2 significantly inhibited AngII-induced aortic dilatation and rupture of the suprarenal aorta (SRA), and development of atherosclerosis within the aortic arch. These effects were blood pressure and plasma lipoprotein independent and associated with Tie2 activation and down-regulation of monocyte chemotactic protein-1 (MCP-1) within the SRA. Plasma concentrations of MCP-1 and interleukin-6 were significantly lower in mice receiving rAngpt2. Immunostaining for the monocyte/macrophage marker MOMA-2 and the angiogenesis marker CD31 within the SRA were less in mice receiving rAngpt2 than controls. The percentage of inflammatory (Ly6Chi) monocytes within the bone marrow was increased while that in peripheral blood was decreased by rAngpt2 administration. In conclusion, administration of rAngpt2 attenuated angiotensin II-induced aortic aneurysm and atherosclerosis in ApoE−/− mice associated with reduced aortic inflammation and angiogenesis. Up-regulation of Angpt2 may have potential therapeutic value in patients with aortic aneurysm and atherosclerosis. PMID:27767064

  16. 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

  17. Comprehensive Plasma Metabolomic Analyses of Atherosclerotic Progression Reveal Alterations in Glycerophospholipid and Sphingolipid Metabolism in Apolipoprotein E-deficient Mice

    PubMed Central

    Dang, Vi T.; Huang, Aric; Zhong, Lexy H.; Shi, Yuanyuan; Werstuck, Geoff H.

    2016-01-01

    Atherosclerosis is the major underlying cause of most cardiovascular diseases. Despite recent advances, the molecular mechanisms underlying the pathophysiology of atherogenesis are not clear. In this study, comprehensive plasma metabolomics were used to investigate early-stage atherosclerotic development and progression in chow-fed apolipoprotein E-deficient mice at 5, 10 and 15 weeks of age. Comprehensive plasma metabolomic profiles, based on 4365 detected metabolite features, differentiate atherosclerosis-prone from atherosclerosis-resistant models. Metabolites in the sphingomyelin pathway were significantly altered prior to detectable lesion formation and at all subsequent time-points. The cytidine diphosphate-diacylglycerol pathway was up-regulated during stage I of atherosclerosis, while metabolites in the phosphatidylethanolamine and glycosphingolipid pathways were augmented in mice with stage II lesions. These pathways, involving glycerophospholipid and sphingolipid metabolism, were also significantly affected during the course of atherosclerotic progression. Our findings suggest that distinct plasma metabolomic profiles can differentiate the different stages of atherosclerotic progression. This study reveals that alteration of specific, previously unreported pathways of glycerophospholipid and sphingolipid metabolism are associated with atherosclerosis. The clear difference in the level of several metabolites supports the use of plasma lipid profiling as a diagnostic tool of atherogenesis. PMID:27721472

  18. Apolipoprotein E polymorphism in elderly Japanese-Brazilian immigrants does not explain the reduced cardiovascular risk factor incidence.

    PubMed

    Terra, N; Moriguchi, Y; Bittencourt, L; Trois, R S; Piccoli, J E C; Cruz, I B M

    2011-01-01

    Study of immigrant populations may contribute to a better understanding of the epidemiology of diseases associated with the aging process. We examined the prevalence of cardiovascular risk factors, including apolipoprotein E (ApoE) polymorphism, in elderly subjects who were born in Japan, migrated to South Brazil and have lived in that region for over 40 years, versus a group of elderly, locally born Brazilians living in the same region. These Japanese subjects came to Brazil after World War II (1950-1960) from several Japanese cities, mainly Nagasaki, Kumamoto and Hokkaido. Among 1007 subjects genotyped for ApoE polymorphism, we selected 540 elderly subjects (>60 years old), consisting of 270 Japanese-Brazilians and 270 Brazilians of European ancestry from Rio Grande do Sul State (Gaucha population). The Japanese-Brazilian group had significantly lower prevalences of obesity, type 2 diabetes mellitus, dyslipidemia, and metabolic syndrome than did the Gaucho population group. ApoE polymorphism frequencies were similar in the two groups. The differences in cardiovascular risk factors observed in the two populations cannot be explained by ApoE polymorphism; they could be related to conservation of Japanese lifestyle habits, such as diet. PMID:21948760

  19. Apolipoprotein E as a Therapeutic Target in Alzheimer's Disease: A Review of Basic Research and Clinical Evidence.

    PubMed

    Yamazaki, Yu; Painter, Meghan M; Bu, Guojun; Kanekiyo, Takahisa

    2016-09-01

    Alzheimer's disease (AD) is a devastating neurodegenerative disorder that causes progressive cognitive decline. The majority of AD cases are sporadic and late-onset (>65 years old) making it the leading cause of dementia in the elderly. While both genetic and environmental factors contribute to the development of late-onset AD (LOAD), APOE polymorphism is a major genetic risk determinant for LOAD. In humans, the APOE gene has three major allelic variants: ε2, ε3, and ε4, of which APOE ε4 is the strongest genetic risk factor for LOAD, whereas APOE ε2 is protective. Mounting evidence suggests that APOE ε4 contributes to AD pathogenesis through multiple pathways including facilitated amyloid-β deposition, increased tangle formation, synaptic dysfunction, exacerbated neuroinflammation, and cerebrovascular defects. Since APOE modulates multiple biological processes through its corresponding protein apolipoprotein E (apoE), APOE gene and apoE properties have been a promising target for therapy and drug development against AD. In this review, we summarize the current evidence regarding how the APOE ε4 allele contributes to the pathogenesis of AD and how relevant therapeutic approaches can be developed to target apoE-mediated pathways in AD. PMID:27328687

  20. 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

  1. 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.

  2. Smoking influences the association between apolipoprotein E and lipids: the National Heart, Lung, and Blood Institute Family Heart Study.

    PubMed

    Djoussé, L; Myers, R H; Coon, H; Arnett, D K; Province, M A; Ellison, R C

    2000-08-01

    Apolipoprotein E allele 4 (apo epsilon4) and smoking each have been associated with an unfavorable lipid profile. We used data collected on 1,472 subjects in the National Heart, Lung, and Blood Institute Family Heart Study to assess whether smoking interacts with apo epsilon4 to influence the levels of plasma lipids. We dichotomized smoking and apo epsilon4 and used analysis of covariance to estimate the means of lipids. Smokers had lower body mass index, were younger, and consumed less fruits and vegetables. Among individuals without apo epsilon4, comparing nonsmokers with smokers, mean low density lipoprotein cholesterol (LDL) was 129.3 and 134.4 mg/dL, respectively, for women and 126.1 and 127.6 mg/dL, respectively, for men. Among subjects with an apo epsilon4 allele, corresponding means were 132.0, and 152.9 mg/dL, respectively, for women and 131.3 and 137.3 mg/dL, respectively, for men (Pfor interaction <0.001 for women and 0.11 for men). A similar interaction was observed for total cholesterol among women (P = 0.02). This study shows a statistically significant effect modification of the relation of apo epsilon4 to LDL and total cholesterol by smoking among women. Smoking may enhance genetic susceptibility to an unfavorable lipid profile among subjects with apo epsilon4. PMID:10984105

  3. 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

  4. Maternal apolipoprotein E genotype as a potential risk factor for poor birth outcomes: The Bogalusa Heart Study

    PubMed Central

    Jacobs, Marni B.; Harville, Emily W.; Kelly, Tanika N.; Bazzano, Lydia A.; Chen, Wei

    2016-01-01

    Objective To assess the association between apolipoprotein E (apoE) genotype and preterm birth (PTB) and small for gestational age (SGA). Study Design ApoE phenotyping was performed on 680 women linked to 1 065 births. Allele frequencies were compared and PTB and SGA risk was estimated using log-binomial regression. Results The ε2 allele was more common in SGA births (p < 0.01). SGA risk was increased among ε2 carriers compared to genotype ε3/ε3, though associations were attenuated following adjustment for maternal age, education, race, smoking, and prenatal visits. Stronger associations were observed for term SGA (first birth: aRR = 1.78, 95% CI 1.06 – 2.98; any birth: aRR = 1.52, 95% CI 0.96 – 2.40) and among whites specifically (first: aRR = 2.88, 95% CI 1.45 – 5.69; any: aRR = 2.75, 95% CI 1.46 – 5.22). Conclusions Associations between maternal apoE genotype and SGA may represent decreased fetal growth in women with lower circulating cholesterol levels. PMID:26890557

  5. Apolipoprotein E (ApoE) polymorphism is related to differences in potential fertility in women: a case of antagonistic pleiotropy?

    PubMed

    Jasienska, Grazyna; Ellison, Peter T; Galbarczyk, Andrzej; Jasienski, Michal; Kalemba-Drozdz, Malgorzata; Kapiszewska, Maria; Nenko, Ilona; Thune, Inger; Ziomkiewicz, Anna

    2015-03-22

    The alleles that are detrimental to health, especially in older age, are thought to persist in populations because they also confer some benefits for individuals (through antagonistic pleiotropy). The ApoE4 allele at the ApoE locus, encoding apolipoprotein E (ApoE), significantly increases risk of poor health, and yet it is present in many populations at relatively high frequencies. Why has it not been replaced by natural selection with the health-beneficial ApoE3 allele? ApoE is a major supplier of cholesterol precursor for the production of ovarian oestrogen and progesterone, thus ApoE has been suggested as the potential candidate gene that may cause variation in reproductive performance. Our results support this hypothesis showing that in 117 regularly menstruating women those with genotypes with at least one ApoE4 allele had significantly higher levels of mean luteal progesterone (144.21 pmol l(-1)) than women with genotypes without ApoE4 (120.49 pmol l(-1)), which indicates higher potential fertility. The hormonal profiles were based on daily data for entire menstrual cycles. We suggest that the finding of higher progesterone in women with ApoE4 allele could provide first strong evidence for an evolutionary mechanism of maintaining the ancestral and health-worsening ApoE4 allele in human populations.

  6. Apolipoprotein E4 prevents growth of malaria at the intraerythrocyte stage: implications for differences in racial susceptibility to Alzheimer's disease.

    PubMed

    Fujioka, Hisashi; Phelix, Clyde F; Friedland, Robert P; Zhu, Xiongwei; Perry, Elizabeth A; Castellani, Rudy J; Perry, George

    2013-11-01

    Apolipoprotein E 4 (ApoE 4) has been linked to pathogenesis of Alzheimer's disease and has been suggested to be maintained through evolutionary pressure via a protective role in malaria infection. We evaluated Plasmodium falciparum viability at the intraerythrocyte stage by exposure to plasma from human subjects with ApoE 4/4 or ApoE 3/3. Plasma samples from ApoE 4/4 but not ApoE 3/3 donors inhibited growth and disrupted morphology of P. falciparum. Evolutionary history is characterized by war between pathogenic microorganisms and defense mechanisms countering their pathogenicities. ApoE 4 frequency is highest in sub-Saharan Africa and other isolated populations (e.g., Papua New Guinea) that exhibit endemic malaria. High ApoE frequency may offer selective advantage protecting against some infectious diseases (e.g., Plasmodium falciparum). These results implicate evolutionary pressure by malaria selecting humans with ApoE 4/4, even considering lower survival in late life. These selective advantages may be relevant in the exploration of possible disparities between Black and Whites in the incidence of Alzheimer's Disease.

  7. 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.

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

    PubMed

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

    2016-06-01

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

  9. 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.

  10. Accelerated pericyte degeneration and blood-brain barrier breakdown in apolipoprotein E4 carriers with Alzheimer's disease.

    PubMed

    Halliday, Matthew R; Rege, Sanket V; Ma, Qingyi; Zhao, Zhen; Miller, Carol A; Winkler, Ethan A; Zlokovic, Berislav V

    2016-01-01

    The blood–brain barrier (BBB) limits the entry of neurotoxic blood-derived products and cells into the brain that is required for normal neuronal functioning and information processing. Pericytes maintain the integrity of the BBB and degenerate in Alzheimer’s disease (AD). The BBB is damaged in AD, particularly in individuals carrying apolipoprotein E4 (APOE4) gene, which is a major genetic risk factor for late-onset AD. The mechanisms underlying the BBB breakdown in AD remain, however, elusive. Here, we show accelerated pericyte degeneration in AD APOE4 carriers >AD APOE3 carriers >non-AD controls, which correlates with the magnitude of BBB breakdown to immunoglobulin G and fibrin. We also show accumulation of the proinflammatory cytokine cyclophilin A (CypA) and matrix metalloproteinase-9 (MMP-9) in pericytes and endothelial cells in AD (APOE4 >APOE3), previously shown to lead to BBB breakdown in transgenic APOE4 mice. The levels of the apoE lipoprotein receptor, low-density lipoprotein receptor-related protein-1 (LRP1), were similarly reduced in AD APOE4 and APOE3 carriers. Our data suggest that APOE4 leads to accelerated pericyte loss and enhanced activation of LRP1-dependent CypA–MMP-9 BBB-degrading pathway in pericytes and endothelial cells, which can mediate a greater BBB damage in AD APOE4 compared with AD APOE3 carriers.

  11. Apolipoprotein E polymorphism and functional disability in Brazilian elders: the Bambuí Health and Aging Study.

    PubMed

    Megale, Rodrigo Zunzarren; de Loyola Filho, Antônio Ignácio; Firmo, Josélia Oliveira Araújo; Lima-Costa, Maria Fernanda; Peixoto, Sérgio Viana

    2016-02-01

    Numerous studies have associated the apolipoprotein E (apoE) ε4 allele with worse health status, but few have assessed the existence of genotype-dependent variations in functional performance. Among participants in the Bambuí Health and Aging Study, Minas Gerais State, Brazil, 1,408 elderly underwent apoE genotyping. Functionality was assessed with a questionnaire, and individuals were classified as dependent in basic activities of daily living (BADLs), instrumental activities of daily living (IADLs), and mobility. The association between apoE genotype and functional status was assessed by logistic regression, taking confounding factors into account. Presence of ε4 allele was associated with lower odds of mobility deficit (OR = 0.65; 95%CI: 0.47-0.92) in the adjusted analysis. There were no significant differences in relation to presence of dependency in BADLs and IADLs. The reasons are not entirely understood, but they may involve the role of ε4 allele as a "thrifty gene" in a sample exposed to high risk of infectious and nutritional diseases in the past.

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

    PubMed

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

    2016-03-01

    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.T he 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.O ur 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.

  13. Dataset on inflammatory proteins expressions and sialic acid levels in apolipoprotein E-deficient mice with administration of N-acetylneuraminic acid and/or quercetin.

    PubMed

    Dong, Rongrong; Li, Fahui; Qin, Shucun; Wang, Yi; Si, Yanhong; Xu, Xuelian; Tian, Hua; Zhai, Lei; Zhang, Guangjie; Li, Yongjun; Zhou, Yawei; Zhang, Ying; Zhang, Nan; Guo, Shoudong

    2016-09-01

    The data presented in this article describe an effect of N-acetylneuraminic acid and/or quercetin on the inflammatory proteins expressions (TNF-α, ICAM-1, VCAM-1 and MOMA-2) and the N-acetylneuraminic acid (NANA) levels of apolipoprotein E-deficient mice that are given a high-fat diet. Protein expression was performed by immunohistochemical imaging and NANA was quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) or semi-quantified using Image-Pro Plus software after ligation with fluorescein-5-thiosemicarbazide (FTSC). Further interpretation and discussion could be found at our research article entitled "Exogenous supplement of N-acetylneuraminic acid ameliorates atherosclerosis in apolipoprotein E-deficient mice" (Guo et al., 2016) [1]. PMID:27419199

  14. Involvement of toll-like receptor 2 and 4 in association between dyslipidemia and osteoclast differentiation in apolipoprotein E deficient rat periodontium

    PubMed Central

    2013-01-01

    Background Dyslipidemia increases circulating levels of oxidized low-density lipoprotein (OxLDL) and this may induce alveolar bone loss through toll-like receptor (TLR) 2 and 4. The purpose of this study was to investigate the effects of dyslipidemia on osteoclast differentiation associated with TLR2 and TLR4 in periodontal tissues using a rat dyslipidemia (apolipoprotein E deficient) model. Methods Levels of plasma OxLDL, and the cholesterol and phospholipid profiles in plasma lipoproteins were compared between apolipoprotein E-deficient rats (16-week-old males) and wild-type (control) rats. In the periodontal tissue, we evaluated the changes in TLR2, TLR4, receptor activator of nuclear factor kappa B ligand (RANKL) and tartrate resistant acid phosphatase (TRAP) expression. Results Apolipoprotein E-deficient rats showed higher plasma levels of OxLDL than control rats (p<0.05), with higher plasma levels of total cholesterol (p<0.05) and LDL-cholesterol (p<0.05) and lower plasma levels of high-density lipoprotein cholesterol (p<0.05). Their periodontal tissue also exhibited a higher ratio of RANKL-positive cells and a higher number of TRAP-positive osteoclasts than control rats (p<0.05). Furthermore, periodontal gene expression of TLR2, TLR4 and RANKL was higher in apolipoprotein E-deficient rats than in control rats (p<0.05). Conclusion These findings underscore the important role for TLR2 and TLR4 in mediating the osteoclast differentiation on alveolar bone response to dyslipidemia. PMID:23295061

  15. Expression of mRNA of apolipoprotein E, apolipoprotein A-IV, and matricellular proteins in the myocardium and intensity of fibroplastic processes during experimental hypercholesterolemia.

    PubMed

    Lushnikova, E L; Nepomnyashchikh, L M; Pichigin, V I; Klinnikova, M G; Nepomnyashchikh, R D; Sergeevichev, D S

    2013-12-01

    The expression of mRNA of matricellular proteins (osteopontin, and lumican), apolipoproteins E and A-IV, and microsomal triglyceride transfer protein, and the intensity of fibroplastic processes were studied in the myocardium of rats during experimental chronic hypercholesterolemia. We have found that the development of chronic hypercholesterolemia was followed by an increase in volume density of interstitial connective tissue in the myocardium reflecting the activation of fibroplastic processes. A slight positive correlation was observed between the connective tissue density in the myocardium and expression of osteopontin mRNA (r=0.408) and lumican mRNA (r=0.470). Myocardium remodeling during hypercholesterolemia is realized against the background of increased expression of apolipoproteins E and A-IV mRNA and microsomal triglyceride transfer protein mRNA involved in transport and metabolism of lipoproteins in several tissues and probably play a pivotal role in the regulation of lipoprotein transport and metabolism in the myocardium. We concluded that the increase in the expression of apolipoproteins (E and A-IV) and microsomal triglyceride transfer protein play adaptive and compensatory role and is related to the increase in lipoprotein utilization by macrophages.

  16. A Phytophthora sojae effector PsCRN63 forms homo-/hetero-dimers to suppress plant immunity via an inverted association manner

    PubMed Central

    Li, Qi; Zhang, Meixiang; Shen, Danyu; Liu, Tingli; Chen, Yanyu; Zhou, Jian-Min; Dou, Daolong

    2016-01-01

    Oomycete pathogens produce a large number of effectors to promote infection. Their mode of action are largely unknown. Here we show that a Phytophthora sojae effector, PsCRN63, suppresses flg22-induced expression of FRK1 gene, a molecular marker in pathogen-associated molecular patterns (PAMP)-triggered immunity (PTI). However, PsCRN63 does not suppress upstream signaling events including flg22-induced MAPK activation and BIK1 phosphorylation, indicating that it acts downstream of MAPK cascades. The PsCRN63-transgenic Arabidopsis plants showed increased susceptibility to bacterial pathogen Pseudomonas syringae pathovar tomato (Pst) DC3000 and oomycete pathogen Phytophthora capsici. The callose deposition were suppressed in PsCRN63-transgenic plants compared with the wild-type control plants. Genes involved in PTI were also down-regulated in PsCRN63-transgenic plants. Interestingly, we found that PsCRN63 forms an dimer that is mediated by inter-molecular interactions between N-terminal and C-terminal domains in an inverted association manner. Furthermore, the N-terminal and C-terminal domains required for the dimerization are widely conserved among CRN effectors, suggesting that homo-/hetero-dimerization of Phytophthora CRN effectors is required to exert biological functions. Indeed, the dimerization was required for PTI suppression and cell death-induction activities of PsCRN63. PMID:27243217

  17. Nuclear microprobe investigation into the trace elemental contents of carotid artery walls of apolipoprotein E deficient mice

    NASA Astrophysics Data System (ADS)

    Minqin, Ren; En, Huang; Beck, Konstanze; Rajendran, Reshmi; Wu, Ben J.; Halliwell, Barry; Watt, Frank; Stocker, Roland

    2007-07-01

    Atherosclerosis is a progressive disease that causes lesions in large and medium-sized arteries. There is increasing evidence that the function of vascular endothelial cells is impaired by oxidation reactions, and that metal ions may participate in these processes. The nuclear microscopy facility in NUS, which has the ability to focus a 2 MeV proton beam down to sub micron spot sizes, was used to investigate the trace elemental changes (e.g. Zn and Fe) in atherosclerotic lesions in the common carotid artery of apolipoprotein E deficient mice fed a high fat diet. In this preliminary study, which is part of a larger study to investigate the effects of probucol on carotid artery atherosclerosis, two sets of mice were used; a test set fed a high fat diet +1% probucol, and a control set which was fed a high fat diet only. The results show that the Zn/Fe ratio was significantly higher in the media of arteries of probucol treated animals without overlying lesion (4.3) compared to the media with overlying lesion (1.3) ( p = 0.004) for test mice. For the control mice, the arterial Zn/Fe ratio was 1.8 for media without overlying lesion, compared with 1.0 for media with overlying lesion ( p = 0.1). Thus, for media without overlying lesion, the Zn/Fe ratio was significantly higher ( p = 0.009) in probucol-treated (4.3) than control mice (1.8), whereas there was little difference in the ratios between the two groups in media with overlying lesion (1.3 compared with 1.0). These preliminary results are consistent with the idea that the levels of iron and zinc concentrations within the artery wall may influence the formation of atherosclerotic plaque in the carotid artery.

  18. Apolipoprotein E ε4 Modulates Cognitive Profiles, Hippocampal Volume, and Resting-State Functional Connectivity in Alzheimer's Disease.

    PubMed

    Wang, Xiao; Wang, Jinhui; He, Yi; Li, Huiying; Yuan, Huishu; Evans, Alan; Yu, Xin; He, Yong; Wang, Huali

    2015-01-01

    The apolipoprotein E ε4 (APOE ε4) allele is a well-established genetic risk factor for Alzheimer's disease (AD). Numerous studies have suggested that the modulation of APOE ε4 affects cognition and brain structure and function in healthy populations, particularly in the hippocampus, a key area associated with AD pathology. However, the effect of APOE ε4 allele on cognitive performance, hippocampal structural morphology, and specifically on functional characteristics in patients with AD remains poorly understood. Here, we employed a neuropsychological battery test and multi-modal structural MRI and resting-state functional MRI dataset to systematically investigate cognitive performance, hippocampal structural volume, and functional properties (including local low-frequency oscillating amplitude, intra-regional functional synchrony, and inter-regional functional connectivity) in 16 APOE ε4-carriers and 26 non-carriers at early stages of AD. Compared to non-carriers, APOE ε4-carriers exhibited poorer performance on recognition performance, but performed better on the late item generation of the verbal fluency task (associated with executive function). Structural imaging analysis revealed that APOE ε4-carriers exhibited smaller left hippocampal volumes compared to non-carriers, and the result remains significant after correcting for effects of brain size. Functional imaging analysis revealed that APOE ε4-carriers exhibited decreased amplitude of low-frequency fluctuations in the left hippocampus, non-significant changes in intra-regional synchronization within the hippocampus and decreased hippocampal functional connectivity predominantly in components of the default-mode network including the medial frontal and parietal cortices and the lateral temporal cortical regions. Taken together, our results showed APOE genotypic effects on the cognitive profile and hippocampal structural and functional characteristics in patients at early stages of AD, thus providing

  19. Fibrillin-1 impairment enhances blood-brain barrier permeability and xanthoma formation in brains of apolipoprotein E-deficient mice.

    PubMed

    Van der Donckt, C; Roth, L; Vanhoutte, G; Blockx, I; Bink, D I; Ritz, K; Pintelon, I; Timmermans, J-P; Bauters, D; Martinet, W; Daemen, M J; Verhoye, M; De Meyer, G R Y

    2015-06-01

    We recently reported that apolipoprotein E (ApoE)-deficient mice with a mutation in the fibrillin-1 gene (ApoE(-/-)Fbn1(C1039G+/-)) develop accelerated atherosclerosis with enhanced inflammation, atherosclerotic plaque rupture, myocardial infarction and sudden death. In the brain, fibrillin-1 functions as an attachment protein in the basement membrane, providing structural support to the blood-brain barrier (BBB). Here, we investigated whether fibrillin-1 impairment affects the permeability of the BBB proper and the blood-cerebrospinal fluid barrier (BCSFB), and whether this leads to the accelerated accumulation of lipids (xanthomas) in the brain. ApoE(-/-) (n=61) and ApoE(-/-)Fbn1(C1039G+/-) (n=73) mice were fed a Western-type diet (WD). After 14 weeks WD, a significantly higher permeability of the BBB was observed in ApoE(-/-)Fbn1(C1039G+/-) mice compared to age-matched ApoE(-/-) mice. This was accompanied by leukocyte infiltration, enhanced expression of pro-inflammatory cytokines, matrix metalloproteinases and transforming growth factor-β, and by decreased expression of tight junction proteins claudin-5 and occludin. After 20 weeks WD, 83% of ApoE(-/-)Fbn1(C1039G+/-) mice showed xanthomas in the brain, compared to 23% of their ApoE(-/-) littermates. Xanthomas were mainly located in fibrillin-1-rich regions, such as the choroid plexus and the neocortex. Our findings demonstrate that dysfunctional fibrillin-1 impairs BBB/BCSFB integrity, facilitating peripheral leukocyte infiltration, which further degrades the BBB/BCSFB. As a consequence, lipoproteins can enter the brain, resulting in accelerated formation of xanthomas. PMID:25797463

  20. Thyroid hormone receptor-α deletion decreases heart function and exercise performance in apolipoprotein E-deficient mice.

    PubMed

    Liu, Kiao Ling; Canaple, Laurence; Del Carmine, Peggy; Gauthier, Karine; Beylot, Michel; Lo, Ming

    2016-02-01

    The deletion of thyroid hormone receptor-α (TRα) in atherosclerosis-prone apolipoprotein E-deficient (ApoE(-/-)) mice (ApoE(-/-)TRα(0/0)) accelerates the formation of atherosclerotic plaques without aggravation of hypercholesterolemia. To evaluate other predisposition risk factors to atherosclerosis in this model, we studied blood pressure (BP) and cardiac and vascular functions, as well as exercise tolerance in young adult ApoE(-/-)TRα(0/0) mice before the development of atherosclerotic plaques. Telemetric BP recorded for 4 consecutive days showed that the spontaneous systolic BP was slightly decreased in ApoE(-/-)TRα(0/0) compared with ApoE(-/-) mice associated with a reduced locomotor activity. The percentage of animals that completed endurance (57% vs. 89%) and maximal running (0% vs. 89% at 46 cm/s speed in ApoE(-/-)TRα(0/0) and ApoE(-/-) mice, respectively) tests was lower in ApoE(-/-)TRα(0/0) mice. Moreover, during the maximal running test, both maximal running speed and running distance were significantly reduced in ApoE(-/-)TRα(0/0) mice, associated with a blunted BP response to exercise. Transthoracic echocardiography revealed a decreased interventricular septum thickness and an increased end-systolic left ventricular volume in ApoE(-/-)TRα(0/0) mice. Accordingly, left ventricular fractional shortening, ejection fraction, and stroke volume were all significantly decreased in ApoE(-/-)TRα(0/0) mice with a concomitant blunted cardiac output. No interstrain difference was observed in vascular reactivity, except that ApoE(-/-)TRα(0/0) mice exhibited an enhanced acetylcholine-induced relaxation in mesenteric and distal femoral arteries. In conclusion, the deletion of TRα in ApoE(-/-) mice alters cardiac structure and contractility; both could contribute to blunted BP response to physical exercise and impaired exercise performance.

  1. Apolipoprotein E (APOE) genotype has dissociable effects on memory and attentional-executive network function in Alzheimer's disease.

    PubMed

    Wolk, David A; Dickerson, Bradford C

    2010-06-01

    The epsilon4 allele of the apolipoprotein E (APOE) gene is the major genetic risk factor for Alzheimer's disease (AD), but limited work has suggested that APOE genotype may modulate disease phenotype. Carriers of the epsilon4 allele have been reported to have greater medial temporal lobe (MTL) pathology and poorer memory than noncarriers. Less attention has focused on whether there are domains of cognition and neuroanatomical regions more affected in noncarriers. Further, a major potential confound of prior in vivo studies is the possibility of different rates of clinical misdiagnosis for carriers vs. noncarriers. We compared phenotypic differences in cognition and topography of regional cortical atrophy of epsilon4 carriers (n = 67) vs. noncarriers (n = 24) with mild AD from the Alzheimer's Disease Neuroimaging Initiative, restricted to those with a cerebrospinal fluid (CSF) molecular profile consistent with AD. Between-group comparisons were made for psychometric tests and morphometric measures of cortical thickness and hippocampal volume. Carriers displayed significantly greater impairment on measures of memory retention, whereas noncarriers were more impaired on tests of working memory, executive control, and lexical access. Consistent with this cognitive dissociation, carriers exhibited greater MTL atrophy, whereas noncarriers had greater frontoparietal atrophy. Performance deficits in particular cognitive domains were associated with disproportionate regional brain atrophy within nodes of cortical networks thought to subserve these cognitive processes. These convergent cognitive and neuroanatomic findings in individuals with a CSF molecular profile consistent with AD support the hypothesis that APOE genotype modulates the clinical phenotype of AD through influence on specific large-scale brain networks. PMID:20479234

  2. Copper chelation by tetrathiomolybdate inhibits vascular inflammation and atherosclerotic lesion development in apolipoprotein E-deficient mice.

    PubMed

    Wei, Hao; Zhang, Wei-Jian; McMillen, Timothy S; Leboeuf, Renee C; Frei, Balz

    2012-08-01

    Endothelial activation, which is characterized by upregulation of cellular adhesion molecules and pro-inflammatory chemokines and cytokines, and consequent monocyte recruitment to the arterial intima are etiologic factors in atherosclerosis. Redox-active transition metal ions, such as copper and iron, may play an important role in endothelial activation by stimulating redox-sensitive cell signaling pathways. We have shown previously that copper chelation by tetrathiomolybdate (TTM) inhibits LPS-induced acute inflammatory responses in vivo. Here, we investigated whether TTM can inhibit atherosclerotic lesion development in apolipoprotein E-deficient (apoE-/-) mice. We found that 10-week treatment of apoE-/- mice with TTM (33-66 ppm in the diet) reduced serum levels of the copper-containing protein, ceruloplasmin, by 47%, and serum iron by 26%. Tissue levels of "bioavailable" copper, assessed by the copper-to-molybdenum ratio, decreased by 80% in aorta and heart, whereas iron levels of these tissues were not affected by TTM treatment. Furthermore, TTM significantly attenuated atherosclerotic lesion development in whole aorta by 25% and descending aorta by 45% compared to non-TTM treated apoE-/- mice. This anti-atherogenic effect of TTM was accompanied by several anti-inflammatory effects, i.e., significantly decreased serum levels of soluble vascular cell and intercellular adhesion molecules (VCAM-1 and ICAM-1); reduced aortic gene expression of VCAM-1, ICAM-1, monocyte chemotactic protein-1, and pro-inflammatory cytokines; and significantly less aortic accumulation of M1 type macrophages. In contrast, serum levels of oxidized LDL were not reduced by TTM. These data indicate that TTM inhibits atherosclerosis in apoE-/- mice by reducing bioavailable copper and vascular inflammation, not by altering iron homeostasis or reducing oxidative stress.

  3. Cytochrome P450 1B1 Contributes to the Development of Atherosclerosis and Hypertension in Apolipoprotein E-Deficient Mice.

    PubMed

    Song, Chi Young; Ghafoor, Khuzema; Ghafoor, Hafiz U; Khan, Nayaab S; Thirunavukkarasu, Shyamala; Jennings, Brett L; Estes, Anne M; Zaidi, Sahar; Bridges, Dave; Tso, Patrick; Gonzalez, Frank J; Malik, Kafait U

    2016-01-01

    Cytochrome P450 (CYP) 1B1 contributes to vascular smooth muscle cell growth and hypertension in male mice. This study was conducted to determine the contribution of CYP1B1 to the development of atherosclerosis and hypertension and associated pathogenesis in 8-week-old male apolipoprotein E-deficient (ApoE(-/-)/Cyp1b1(+/+)), and ApoE- and CYP1B1-deficient (ApoE(-/-)/Cyp1b1(-/-)) mice fed a normal or atherogenic diet for 12 weeks. A separate group of ApoE(-/-)/Cyp1b1(+/+) mice on an atherogenic diet was injected every third day with the CYP1B1 inhibitor, 2,3',4,5'-tetramethoxystilbene (300 μg/kg), or its vehicle, dimethyl sulfoxide (30 μL, IP); systolic blood pressure was measured by the tail cuff method. After 12 weeks, mice were euthanized, blood collected for lipid analysis, and aortas harvested for measuring lesions and remodeling, and for infiltration of inflammatory cells by histological and immunohistochemical analysis, respectively, and for reactive oxygen species production. Blood pressure, areas of lipids and collagen deposition, elastin breaks, infiltration of macrophages and T lymphocytes, reactive oxygen species generation in the aorta, and plasma lipid levels were increased in ApoE(-/-)/Cyp1b1(+/+) mice on an atherogenic diet; these changes were minimized in mice given 2,3',4,5'-tetramethoxystilbene, and in ApoE(-/-)/Cyp1b1(-/-) mice on an atherogenic diet; absorption/production of lipids remained unaltered in these mice. These data suggest that aortic lesions, hypertension, and associated pathogenesis in ApoE(-/-)/Cyp1b1(+/+) mice on an atherogenic diet are most likely dependent on CYP1B1-generated oxidative stress and increased plasma lipid levels independent of blood pressure and absorption of lipids. CYP1B1 could serve as a novel target for developing drugs to treat atherosclerosis and hypertension caused by hypercholesterolemia.

  4. Aronia melanocarpa (chokeberry) polyphenol-rich extract improves antioxidant function and reduces total plasma cholesterol in apolipoprotein E knockout mice.

    PubMed

    Kim, Bohkyung; Ku, Chai Siah; Pham, Tho X; Park, Youngki; Martin, Derek A; Xie, Liyang; Taheri, Rod; Lee, Jiyoung; Bolling, Bradley W

    2013-05-01

    We hypothesized that a polyphenol-rich chokeberry extract (CBE) would modulate hepatic lipid metabolism and improve antioxidant function in apolipoprotein E knockout (apoE(-/-)) mice. ApoE(-/-) mice were fed diets containing 15% fat with 0.2% cholesterol alone or supplemented with 0.005% or 0.05% CBE for 4 weeks. CBE polyphenol content was determined by the total phenols, 4-dimethylaminocinnamaldehyde, and ultra high-performance liquid chromatography-mass spectrometry methods. The 0.05% CBE diet provided mice with mean daily doses of 1.2 mg gallic acid equivalents of total phenols, 0.19 mg anthocyanins, 0.17 mg phenolic acids, 0.06 mg proanthocyanidins (as catechin-equivalents), and 0.02 mg flavonols. The 0.05% CBE group had 12% less plasma total cholesterol concentrations than the control. Despite the hypocholesterolemic effect of CBE, hepatic mRNA levels of low-density lipoprotein receptor, hydroxyl-3-methylglutaryl coenzyme A reductase and cholesterol 7α-hydroxylase in CBE-fed mice were not significantly different from controls. Dietary CBE did not alter hepatic lipid content or the hepatic expression of genes involved in lipogenesis and fatty acid β-oxidation such as fatty acid synthase, carnitine palmitoyltransferase 1 and acyl-CoA oxidase. Plasma paraoxonase and catalase activities were significantly increased in mice fed 0.05% CBE. Both CBE diets increased hepatic glutathione peroxidase (GPx) activity but the 0.05% CBE group had 24% less proximal intestine GPx activity relative to controls. Thus, dietary CBE lowered total cholesterol and improved plasma and hepatic antioxidant function at nutritionally-relevant doses in apoE(-/-) mice. Furthermore, the CBE cholesterol-lowering mechanism in apoE(-/-) mice was independent of hepatic expression of genes involved in cholesterol metabolism.

  5. Attenuation of atherosclerotic lesions in diabetic apolipoprotein E-deficient mice using gene silencing of macrophage migration inhibitory factor

    PubMed Central

    Sun, Hui; Zhang, XianJun; Zhao, Lei; Zhen, Xi; Huang, ShanYing; Wang, ShaSha; He, Hong; Liu, ZiMo; Xu, NaNa; Yang, FaLin; Qu, ZhongHua; Ma, ZhiYong; Zhang, Cheng; Zhang, Yun; Hu, Qin

    2015-01-01

    Macrophage migration inhibitory factor (MIF) involves the pathogenesis of atherosclerosis (AS) and increased plasma MIF levels in diabetes mellitus (DM) patients are associated with AS. Here, we have been suggested that MIF could be a critical contributor for the pathological process of diabetes-associated AS by using adenovirus-mediated RNA interference. First, streptozotocin (STZ)-induced diabetic animal model was constructed in 114 apolipoprotein E-deficient mice (apoE−/− mice) fed on a regular chow diet. Then, the animals were randomly divided into three groups: Adenovirus-mediated MIF interference (Ad-MIFi), Ad-enhanced green fluorescent protein (EGFP) and normal saline (NS) group (n ≈ 33/group). Non-diabetic apoE−/− mice (n = 35) were served as controls. Ad-MIFi, Ad-EGFP and NS were, respectively, injected into the tail vein of mice from Ad-MIFi, Ad-EGFP and NS group, which were injected repeatedly 4 weeks later. Physical, biochemical, morphological and molecular parameters were measured. The results showed that diabetic apoE−/− mice had significantly aggravated atherosclerotic lesions. MIF gene interference attenuated atherosclerotic lesions and stabilized atheromatous plaque, accompanied by the decreased macrophages and lipids deposition and inflammatory cytokines production, improved glucose intolerance and plasma cholesterol level, the decreased ratio of matrix matalloproteinase-2/tissue inhibitor of metalloproteinase-1 and plaque instability index. An increased expression of MIF and its ligand CD74 was also detected in the diabetic patients with coronary artery disease. The results suggest that MIF gene interference is able to inhibit atherosclerotic lesions and increase plaque stability in diabetic apoE−/−mice. MIF inhibition could be a novel and promising approach to the treatment of DM-associated AS. PMID:25661015

  6. Metformin reduces the endotoxin-induced down-regulation of apolipoprotein E gene expression in macrophages

    SciTech Connect

    Stavri, Simona; Trusca, Violeta G.; Simionescu, Maya; Gafencu, Anca V.

    2015-05-29

    The atheroprotective role of macrophage-derived apolipoprotein E (apoE) is well known. Our previous reports demonstrated that inflammatory stress down-regulates apoE expression in macrophages, aggravating atherogenesis. Metformin, extensively used as an anti-diabetic drug, has also anti-inflammatory properties, and thus confers vascular protection. In this study, we questioned whether metformin could have an effect on apoE expression in macrophages in normal conditions or under lipopolysaccharide (LPS)-induced stress. The results showed that metformin slightly increases the apoE expression only at high doses (5–10 mM). Low doses of metformin (1–3 mM) significantly reduce the LPS down-regulatory effect on apoE expression in macrophages. Our experiments demonstrated that LPS-induced NF-κB binds to the macrophage-specific distal regulatory element of apoE gene, namely to the multienhancer 2 (ME.2) and its 5′-deletion fragments. The NF-κB binding on ME.2 and apoE promoter has a down-regulatory effect. In addition, data revealed that metformin impairs NF-κB nuclear translocation, and thus, improves the apoE levels in macrophages under inflammatory stress. The positive effect of metformin in the inflammatory states, its clinical safety and low cost, make this drug a potential adjuvant in the therapeutic strategies for atherosclerosis. - Highlights: • High doses of metformin slightly increase apoE expression in macrophages. • Low doses of metformin up-regulate apoE gene in endotoxin-stressed macrophages. • Metformin reduces the negative effect of LPS on apoE expression by NF-κB inhibition.

  7. Tyrphostin AG490 reduces NAPDH oxidase activity and expression in the aorta of hypercholesterolemic apolipoprotein E-deficient mice.

    PubMed

    Fenyo, Ioana M; Florea, Irina C; Raicu, Monica; Manea, Adrian

    2011-01-01

    Oxidative stress-induced vascular injury represents a major contributor to the pathoetiology of atherosclerosis. Elevated NADPH oxidase (Nox) activity promotes oxidative injury of the cardiovascular cells. Janus-tyrosine-kinase (Jak) family regulate various aspects of the atherosclerotic process e.g., inflammation, cellular growth, proliferation, and migration. Here, we investigated the potential of Jak2 inhibition to counteract Nox-dependent O(2)(•-) formation in atherogenesis in hypercholesterolemic apolipoprotein E-deficient (ApoE(-/-)) mice. Male ApoE(-/-) mice fed a high-fat, cholesterol-rich diet were treated for 5 weeks with either vehicle or tyrphostin AG490 (1 mg/kg), a specific Jak2 inhibitor. Lucigenin-enhanced-chemiluminescence assay, real-time PCR and Western blot analysis revealed that Nox-derived O(2)(•-) generation, Nox1, Nox2, and Nox4 mRNA and protein levels were significantly elevated in the aortas of ApoE(-/-) mice fed a high-fat diet compared to ApoE(-/-) mice fed a normal diet. Treatment with tyrphostin AG490 significantly reduced the up-regulated Nox activity, the expression of each Nox subtype, as well as the protein level of CD68, a macrophage-specific marker. Morphometric analysis showed a marked reduction of atherosclerotic lesions in the aorta of AG490-treated animals. These data provide new insights into the regulation of vascular Nox by tyrphostins in the cardiovascular system. Since Jak2 transduces the signals of various cardiovascular risk factors, pharmacological manipulation of this signaling pathway may represent a novel strategy to reduce oxidative stress in atherosclerosis. PMID:21457788

  8. Apolipoprotein E Genotype-Dependent Paradoxical Short-Term Effects of {sup 56}Fe Irradiation on the Brain

    SciTech Connect

    Haley, Gwendolen E.; Villasana, Laura; Dayger, Catherine; Davis, Matthew J.; Raber, Jacob

    2012-11-01

    Purpose: In humans, apolipoprotein E (apoE) is encoded by three major alleles ({epsilon}2, {epsilon}3, and {epsilon}4) and, compared to apoE3, apoE4 increases the risk of developing Alzheimer disease and cognitive impairments following various environmental challenges. Exposure to irradiation, including that of {sup 56}Fe, during space missions poses a significant risk to the central nervous system, and apoE isoform might modulate this risk. Methods and Materials: We investigated whether apoE isoform modulates hippocampus-dependent cognitive performance starting 2 weeks after {sup 56}Fe irradiation. Changes in reactive oxygen species (ROS) can affect cognition and are induced by irradiation. Therefore, after cognitive testing, we assessed hippocampal ROS levels in ex vivo brain slices, using the ROS-sensitive fluorescent probe, dihydroethidium (DHE). Brain levels of 3-nitrotyrosine (3-NT), CuZn superoxide dismutase (CuZnSOD), extracellular SOD, and apoE were assessed using Western blotting analysis. Results: In the water maze, spatial memory retention was impaired by irradiation in apoE2 and apoE4 mice but enhanced by irradiation in apoE3 mice. Irradiation reduced DHE-oxidation levels in the enclosed blade of the dentate gyrus and levels of 3-NT and CuZnSOD in apoE2 but not apoE3 or apoE4 mice. Finally, irradiation increased apoE levels in apoE3 but not apoE2 or apoE4 mice. Conclusions: The short-term effects of {sup 56}Fe irradiation on hippocampal ROS levels and hippocampus-dependent spatial memory retention are apoE isoform-dependent.

  9. Is hyperuricemia a risk factor for arteriosclerosis? Uric acid and arteriosclerosis in apolipoprotein e-deficient mice.

    PubMed

    Wakuda, Hirokazu; Uchida, Shinya; Ikeda, Masahiko; Tabuchi, Masaki; Akahoshi, Yasumitsu; Shinozuka, Kazumasa; Yamada, Shizuo

    2014-01-01

    Although hyperlipidemia, high blood pressure, and diabetes increase the risk of arteriosclerosis, it is not clear whether hyperuricemia increases the risk of arteriosclerosis or not. We examined the effects of uric acid and curative drugs for hyperuricemia on atherosclerosis-susceptible C57BL/6J apolipoprotein E-deficient (apoE(-/-)) mice. Male apoE(-/-) mice (age: 6 weeks) were fed a normal diet (normal diet group) or a uric acid-enriched diet. Mice fed the uric acid-enriched diet were divided into three groups and administered a drinking vehicle (high uric acid diet group), allopurinol (20 mg·kg(-1)·d(-1)), or benzbromarone (20 mg·kg(-1)·d(-1)) for 10 weeks. Serum uric acid concentrations were higher in the high uric acid diet group than in the normal diet group, and concentrations in the allopurinol and benzbromarone groups were lower than in the high uric acid diet group. Serum total cholesterol and triglyceride levels were lower in the allopurinol group than in the high uric acid diet group. Oxidative stress was lower in the benzbromarone group than in the high uric acid diet group. Atherosclerotic lesion areas were smaller in the allopurinol and benzbromarone groups than in the high uric acid diet group. Thus, hyperuricemia may not be an independent risk factor for arteriosclerosis; however, the administration of allopurinol and benzbromarone prevented the development of atherosclerosis in apoE(-/-) mice fed a uric acid-enriched diet. The anti-atherosclerotic effect was in part due to lower total cholesterol and oxidative stress in the serum. Other possible mechanisms underlying this effect should be investigated.

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

    PubMed

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

    2016-08-01

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

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

    PubMed Central

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

    2010-01-01

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

  12. Apolipoprotein E and Clusterin can Magnify Effects of Personality Vulnerability on Declarative Memory Performance in Non-Demented Older Adults

    PubMed Central

    Sapkota, Shraddha; Wiebe, Sandra A.; Small, Brent J.; Dixon, Roger A.

    2016-01-01

    Objectives Recent research has linked psychological (personality) factors and specific genetic risk polymorphisms to performance on neurocognitive phenotypes. We examined whether episodic or semantic memory performance is associated with (a) three personality traits (i.e., neuroticism, extraversion, openness to experience), (b) two neurodegenerative-related polymorphisms (i.e., Apolipoprotein E (APOE; rs7412; rs429358), Clusterin (CLU; rs11136000)), and (c) cross-domain risk interactions (magnification effects). Methods Linear growth models were examined to test independent associations between personality traits and declarative memory performance, and potential interaction effects with APOE and CLU genetic risk. Normal older adults (n = 282) with personality and genetic data from the Victoria Longitudinal Study were included at baseline and for up to 14 years of follow-up. Results First, we observed that higher openness to experience levels were associated with better episodic and semantic memory. Second, three significant gene × personality interactions were associated with poorer memory performance at baseline. These synergistic effects are: (a) APOE allelic risk (ε4+) carriers with lower openness to experience levels, (b) CLU (no risk: T/T) homozygotes with higher extraversion levels, and (c) CLU (no risk: T/T) homozygotes with lower neuroticism levels. Conclusions Specific neurodegenerative-related genetic polymorphisms (i.e., APOE and CLU) moderate and magnify the risk contributed by selected personality trait levels (i.e., openness to experience, extraversion) on declarative memory performance in non-demented aging. Future research could target interactions of other personality traits and genetic polymorphisms in different clinical populations for predicting other neurocognitive deficits or transitions to cognitive impairment and dementia. PMID:26343804

  13. Association of apolipoprotein E polymorphism with maximal oxygen uptake after exercise training: a study of Chinese young adult

    PubMed Central

    2014-01-01

    Background Although a few studies have been conducted, it is still unclear whether the apolipoprotein E (APOE) polymorphism is associated with maximal oxygen uptake (VO2max) after exercise training. The objective of this study was to examine if the APOE gene polymorphisms affect VO2max after exercise training in Chinese young adult. Methods A total of 360 Chinese young adult (180 male and 180 female) were recruited into this gender-specific cohorts. Anthropometrics, serum lipids, and VO2max were measured pre and post 6 months of supervised exercise training. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assay was applied to assess the APOE gene polymorphisms. Results VO2max after exercise training increased significantly higher in carriers of E2/E3 in male [odds ratio (OR) =0.68, 95% confidence interval (CI) = 0.04, 1.32; P = 0.04] and female (OR =0.62, 95% CI = 0.05, 1.18; P = 0.03). VO2max after exercise training increased significantly higher in carriers of E3/E4 in male (OR =0.60, 95% CI = 0.09, 1.11; P = 0.02) and female (OR =0.62, 95% CI = 0.09, 1.15; P = 0.02). No significant differences were found in carriers of E2/E2, E2/E4, E3/E3, E4/E4 in either male nor female. Conclusion Our study found that APOE gene polymorphism was associated with VO2max levels after exercise training in Chinese young adult. In the future, further experiments will be necessary to confirm this finding and to find the possible mechanism. PMID:24571688

  14. Synthetic gestagens exert differential effects on arterial thrombosis and aortic gene expression in ovariectomized apolipoprotein E-deficient mice

    PubMed Central

    Freudenberger, T; Deenen, R; Kretschmer, I; Zimmermann, A; Seiler, L F; Mayer, P; Heim, H-K; Köhrer, K; Fischer, J W

    2014-01-01

    Background and Purpose Combined hormone replacement therapy with oestrogens plus the synthetic progestin medroxyprogesterone acetate (MPA) is associated with an increased risk of thrombosis. However, the mechanisms of this pro-thrombotic effect are largely unknown. The purpose of this study was to: (i) compare the pro-thrombotic effect of MPA with another synthetic progestin, norethisterone acetate (NET-A), (ii) determine if MPA's pro-thrombotic effect can be antagonized by the progesterone and glucocorticoid receptor antagonist mifepristone and (iii) elucidate underlying mechanisms by comparing aortic gene expression after chronic MPA with that after NET-A treatment. Experimental Approach Female apolipoprotein E-deficient mice were ovariectomized and treated with placebo, MPA, a combination of MPA + mifepristone or NET-A for 90 days on a Western-type diet. Arterial thrombosis was measured in vivo in a photothrombosis model. Aortic gene expression was analysed using microarrays; GeneOntology and KEGG pathway analyses were conducted. Key Results MPA's pro-thrombotic effects were prevented by mifepristone, while NET-A did not affect arterial thrombosis. Aortic gene expression analysis showed, for the first time, that gestagens induce similar effects on a set of genes potentially promoting thrombosis. However, in NET-A-treated mice other genes with potentially anti-thrombotic effects were also affected, which might counterbalance the effects of the pro-thrombotic genes. Conclusions and Implications The pro-thrombotic effects of synthetic progestins appear to be compound-specific, rather than representing a class effect of gestagens. Furthermore, the different thrombotic responses elicited by MPA and NET-A might be attributed to a more balanced, ‘homeostatic’ gene expression induced in NET-A- as compared with MPA-treated mice. PMID:24923668

  15. Concentration-dependent inhibitory effects of apolipoprotein E on Alzheimer's beta-amyloid fibril formation in vitro.

    PubMed

    Naiki, H; Gejyo, F; Nakakuki, K

    1997-05-20

    Recently, many research groups have examined the effect of apolipoprotein E (apoE) on beta-amyloid fibril (betaAf) formation in vitro. However, their data were somewhat controversial and no exact kinetic assessment of the role of apoE has thus far been available. We examined the effect of human apoE on betaAf formation in vitro, starting with various concentrations of freshly prepared beta-amyloid(1-40) (beta1-40) and using fluorescence spectroscopy with thioflavine T. When 50 microM of beta1-40 was incubated with a 1:1000 to 1:100 molar ratio of apoE, a dose-dependent inhibitory effect of apoE was observed. Both the nucleation and extension phases of betaAf formation in vitro were inhibited by apoE. On the other hand, when 300 microM of beta1-40 was incubated with a 1:100 molar ratio of apoE, the inhibitory effect of apoE was completely abolished. We then focused our study on the kinetics of the inhibitory effect of apoE on the extension phase of betaAf formation in vitro, utilizing the recently established first-order kinetic model of betaAf extension in vitro [Naiki, H., & Nakakuki, K. (1996) Lab. Invest. 74, 374-383]. The mathematical treatment of the data suggests that apoE inhibits the extension of betaAf in vitro, by making a complex with beta1-40, thus eliminating free beta1-40 from the reaction mixture. The equilibrium association constant with beta1-40 was practically the same among the three major recombinant apoE isoforms. These results indicate that the effects of apoE on betaAf formation in vitro is differential and could settle some of the controversy about beta-amyloid-apoE interaction in vitro.

  16. Delivery of negatively charged liposomes into the atherosclerotic plaque of apolipoprotein E-deficient mouse aortic tissue.

    PubMed

    Zhaorigetu, Siqin; Rodriguez-Aguayo, Cristian; Sood, Anil K; Lopez-Berestein, Gabriel; Walton, Brian L

    2014-09-01

    Liposomes have been used to diagnose and treat cancer and, to a lesser extent, cardiovascular disease. We previously showed the uptake of anionic liposomes into the atheromas of Watanabe heritable hyperlipidemic rabbits within lipid pools. However, the cellular distribution of anionic liposomes in atherosclerotic plaque remains undescribed. In addition, how anionic liposomes are absorbed into atherosclerotic plaque is unclear. We investigated the uptake and distribution of anionic liposomes in atherosclerotic plaque in aortic tissues from apolipoprotein E-deficient (ApoE(-/-)) mice. To facilitate the tracking of liposomes, we used liposomes containing fluorescently labeled non-silencing small interfering RNA. Confocal microscopy analysis showed the uptake of anionic liposomes into atherosclerotic plaque and colocalization with macrophages. Transmission electron microscopy analysis revealed anionic liposomal accumulation in macrophages. To investigate how anionic liposomes cross the local endothelial barrier, we examined the role of clathrin-mediated endocytosis in human coronary artery endothelial cells (HCAECs) treated with or without the inflammatory cytokine tumor necrosis factor (TNF)-α. Pretreatment with amantadine, an inhibitor of clathrin-mediated endocytosis, significantly decreased liposomal uptake in HCAECs treated with or without TNF-α by 77% and 46%, respectively. Immunoblot analysis showed that endogenous clathrin expression was significantly increased in HCAECs stimulated with TNF-α but was inhibited by amantadine. These studies indicated that clathrin-mediated endocytosis is partly responsible for the uptake of liposomes by endothelial cells. Our results suggest that anionic liposomes target macrophage-rich areas of vulnerable plaque in ApoE(-)(/)(-) mice; this finding may lead to the development of novel diagnostic and therapeutic strategies for treating vulnerable plaque in humans.

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

    PubMed

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

    2013-12-01

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

  18. Angiotensin converting enzyme inhibitors and the reduced risk of Alzheimer's disease in the absence of apolipoprotein E4 allele.

    PubMed

    Qiu, Wei Qiao; Mwamburi, Mkaya; Besser, Lilah M; Zhu, Haihao; Li, Huajie; Wallack, Max; Phillips, Leslie; Qiao, Liyan; Budson, Andrew E; Stern, Robert; Kowall, Neil

    2013-01-01

    Our cross-sectional study showed that the interaction between apolipoprotein E4 (ApoE4) and angiotensin converting enzyme (ACE) inhibitors was associated with Alzheimer's disease (AD). The aim of this longitudinal study was to differentiate whether ACE inhibitors accelerate or reduce the risk of AD in the context of ApoE alleles. Using the longitudinal data from the National Alzheimer's Coordinating Center (NACC) with ApoE genotyping and documentation of ACE inhibitors use, we found that in the absence of ApoE4, subjects who had been taking central ACE inhibitor use (χ2 test: 21% versus 27%, p = 0.0002) or peripheral ACE inhibitor use (χ2 test: 13% versus 27%, p < 0.0001) had lower incidence of AD compared with those who had not been taking an ACE inhibitor. In contrast, in the presence of ApoE4, there was no such association between ACE inhibitor use and the risk of AD. After adjusting for the confounders, central ACE inhibitor use (OR = 0.68, 95% CI = 0.55, 0.83, p = 0.0002) or peripheral ACE inhibitor use (OR = 0.33, 95% CI = 0.33, 0.68, p < 0.0001) still remained inversely associated with a risk of developing AD in ApoE4 non-carriers. In conclusion, ACE inhibitors, especially peripherally acting ones, were associated with a reduced risk of AD in the absence of ApoE4, but had no such effect in those carrying the ApoE4 allele. A double-blind clinical trial should be considered to determine the effect of ACE inhibitors on prevention of AD in the context of ApoE genotype.

  19. Effect of the factor Xa inhibitor rivaroxaban on arterial thrombosis in wild-type and apolipoprotein E-deficient mice.

    PubMed

    Wagner, Nana-Maria; Dressel, Tobias; Schäfer, Katrin; Konstantinides, Stavros

    2012-11-01

    Rivaroxaban is a potent and specific direct inhibitor of coagulation factor Xa. Recent studies have highlighted its effectiveness in the prevention of venous thrombosis and embolic stroke due to atrial fibrillation. To evaluate the antithrombotic effects of rivaroxaban in an in vivo model of arterial thrombosis, photochemical vascular injury was induced in wild-type mice by intravenous rose bengal (50 mg/kg body weight [BW]) followed by illumination of the left common carotid artery using a 543 nm helium-neon laser beam. Rivaroxaban, injected concomitantly with rose bengal at doses of 1.0, 1.5, 2.0, or 3.0 mg/kg BW, dose-dependently prolonged the times to first thrombotic occlusion and stable thrombosis. Quantitative analysis of carotid flow curves revealed higher blood volumes passing through the injured artery with increasing rivaroxaban doses (P<0.01 and P<0.001 vs. vehicle for 2.0 and 3.0 mg/kg , respectively), suggesting a dose-dependent effect on vascular patency. Consistently, a significantly higher proportion of mice that received 2.0 and 3.0 mg/kg rivaroxaban exhibited patent carotid arteries at the end of the flow monitoring period compared to vehicle alone (P<0.05 and P<0.001, respectively). Histological analysis showed complete thrombotic arterial occlusion in vehicle-treated mice compared to less thrombotic material in mice injected with 3.0 mg/kg rivaroxaban (P<0.05). Rivaroxaban also prolonged the time to cessation of tail bleeding in a dose-dependent manner, starting at 1.5 mg/kg. Similar findings were obtained in apolipoprotein E-knockout mice. Rivaroxaban may exert beneficial effects by preventing arterial thrombosis and vascular occlusion after endothelial injury. PMID:22281071

  20. Apolipoprotein E (APOE) genotype has dissociable effects on memory and attentional-executive network function in Alzheimer's disease.

    PubMed

    Wolk, David A; Dickerson, Bradford C

    2010-06-01

    The epsilon4 allele of the apolipoprotein E (APOE) gene is the major genetic risk factor for Alzheimer's disease (AD), but limited work has suggested that APOE genotype may modulate disease phenotype. Carriers of the epsilon4 allele have been reported to have greater medial temporal lobe (MTL) pathology and poorer memory than noncarriers. Less attention has focused on whether there are domains of cognition and neuroanatomical regions more affected in noncarriers. Further, a major potential confound of prior in vivo studies is the possibility of different rates of clinical misdiagnosis for carriers vs. noncarriers. We compared phenotypic differences in cognition and topography of regional cortical atrophy of epsilon4 carriers (n = 67) vs. noncarriers (n = 24) with mild AD from the Alzheimer's Disease Neuroimaging Initiative, restricted to those with a cerebrospinal fluid (CSF) molecular profile consistent with AD. Between-group comparisons were made for psychometric tests and morphometric measures of cortical thickness and hippocampal volume. Carriers displayed significantly greater impairment on measures of memory retention, whereas noncarriers were more impaired on tests of working memory, executive control, and lexical access. Consistent with this cognitive dissociation, carriers exhibited greater MTL atrophy, whereas noncarriers had greater frontoparietal atrophy. Performance deficits in particular cognitive domains were associated with disproportionate regional brain atrophy within nodes of cortical networks thought to subserve these cognitive processes. These convergent cognitive and neuroanatomic findings in individuals with a CSF molecular profile consistent with AD support the hypothesis that APOE genotype modulates the clinical phenotype of AD through influence on specific large-scale brain networks.

  1. Insulin decreases atherosclerotic plaque burden and increases plaque stability via nitric oxide synthase in apolipoprotein E-null mice.

    PubMed

    Mori, Yusaku; Chiang, Simon; Bendeck, Michelle P; Giacca, Adria

    2016-08-01

    It has been argued whether insulin accelerates or prevents atherosclerosis. Although results from in vitro studies have been conflicting, recent in vivo mice studies demonstrated antiatherogenic effects of insulin. Insulin is a known activator of endothelial nitric oxide synthase (NOS), leading to increased production of NO, which has potent antiatherogenic effects. We aimed to examine the role of NOS in the protective effects of insulin against atherosclerosis. Male apolipoprotein E-null mice (8 wk old) fed a high-cholesterol diet (1.25% cholesterol) were assigned to the following 12-wk treatments: control, insulin (0.05 U/day via subcutaneous pellet), N(ω)-nitro-l-arginine methyl ester hydrochloride (l-NAME, via drinking water at 100 mg/l), and insulin plus l-NAME. Insulin reduced atherosclerotic plaque burden in the descending aorta by 42% compared with control (plaque area/aorta lumen area: control, 16.5 ± 1.9%; insulin, 9.6 ± 1.3%, P < 0.05). Although insulin did not decrease plaque burden in the aortic sinus, macrophage accumulation in the plaque was decreased by insulin. Furthermore, insulin increased smooth muscle actin and collagen content and decreased plaque necrosis, consistent with increased plaque stability. In addition, insulin treatment increased plasma NO levels, decreased inducible NOS staining, and tended to increase phosphorylated vasodilator-stimulated phosphoprotein staining in the plaques of the aortic sinus. All these effects of insulin were abolished by coadministration of l-NAME, whereas l-NAME alone showed no effect. Insulin also tended to increase phosphorylated endothelial NOS and total neuronal NOS staining, effects not modified by l-NAME. In conclusion, we demonstrate that insulin treatment decreases atherosclerotic plaque burden and increases plaque stability through NOS-dependent mechanisms. PMID:27221119

  2. Variable Frequencies of Apolipoprotein E Genotypes and Its Effect on Serum Lipids in the Guangxi Zhuang and Han Children

    PubMed Central

    Hu, Peng; Qin, Yuan Han; Lei, Feng Ying; Pei, Juan; Hu, Bo; Lu, Ling

    2011-01-01

    Guangxi Zhuang, the largest ethnic minority in China, is located in the southern part of the country, and well-known to the world as the longevity village. Studies of apolipoprotein E (APOE) polymorphism in adults suggest the lower frequencies of E4 allele and E4/E4 genotype may account, in part, for the favorable lipid profiles of Guangxi Zhuang. However, the effect of APOE polymorphism on serum lipids in the Guangxi Zhuang children is yet unknown to date. In the present study, genomic DNA was extracted from 278 Guangxi Zhuang and 200 Guangxi Han children. APOE genotypes were determined by PCR-restriction fragment length polymorphism (RFLP) analysis. The fasting serum lipoprotein a [Lp(a)], total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoprotein A1 (apoA1) and apoB were measured. Our results demonstrated that no significant differences in serum lipids were observed between the Guangxi Zhuang and Han children. The E4/E4 and E4/E3 genotypic frequencies were significantly lower in the Guangxi Zhuang children compared with the Guangxi Han children, whereas for E2/E2, E3/E2 and E4/E2 genotypic frequencies the opposite was presented. Though no significant differences in serum lipid concentrations were found for variant alleles both in the Guangxi Zhuang and Han children, the trend was observed in the association of higher levels of Lp(a), TC, TG and LDL-C with E4 allele in the Guangxi Zhuang children. In conclusion, a significant heterogeneity in APOE genetic variation indeed exists between the Guangxi Zhuang and Han ethnic group. The E4 allele may serve as a genetic marker for susceptibility to higher lipid profiles in the Guangxi Zhuang children. Lifestyle should be modified, according to APOE polymorphism even in the young children. PMID:22016612

  3. Apolipoprotein E (APOE) genotype has dissociable effects on memory and attentional–executive network function in Alzheimer’s disease

    PubMed Central

    Wolk, David A.; Dickerson, Bradford C.; Weiner, Michael; Aiello, Marilyn; Aisen, Paul; Albert, Marilyn S.; Alexander, Gene; Anderson, Heather S.; Anderson, Karen; Apostolova, Liana; Arnold, Steve; Ashford, Wes; Assaly, Michele; Asthana, Sanjay; Bandy, Dan; Bartha, Rob; Bates, Vernice; Beckett, Laurel; Bell, Karen L.; Benincasa, Amanda L.; Bergman, Howard; Bernick, Charles; Bernstein, Matthew; Black, Sandra; Blank, Karen; Borrie, Michael; Brand, Connie; Brewer, James; Brown, Alice D.; Burns, Jeffrey M.; Cairns, Nigel J.; Caldwell, Curtis; Capote, Horacio; Carlsson, Cynthia M.; Carmichael, Owen; Cellar, Janet S.; Celmins, Dzintra; Chen, Kewei; Chertkow, Howard; Chowdhury, Munir; Clark, David; Connor, Donald; Correia, Stephen; Crawford, Karen; Dale, Anders; de Leon, Mony J; De Santi, Susan M; DeCarli, Charles; deToledo-Morrell, Leyla; DeVous, Michael; Diaz-Arrastia, Ramon; Dolen, Sara; Donohue, Michael; Doody, Rachelle S.; Doraiswamy, P. Murali; Duara, Ranjan; Englert, Jessica; Farlow, Martin; Feldman, Howard; Felmlee, Joel; Fleisher, Adam; Fletcher, Evan; Foroud, Tatiana M.; Foster, Norm; Fox, Nick; Frank, Richard; Gamst, Anthony; Given, Curtis A.; Graff-Radford, Neill R; Green, Robert C.; Griffith, Randall; Grossman, Hillel; Hake, Ann M.; Hardy, Peter; Harvey, Danielle; Heidebrink, Judith L.; Hendin, Barry A.; Herring, Scott; Honig, Lawrence S.; Hosein, Chris; Robin Hsiung, Ging-Yuek; Hudson, Leon; Ismail, M. Saleem; Jack, Clifford R.; Jacobson, Sandra; Jagust, William; Jayam-Trouth, Annapurni; Johnson, Kris; Johnson, Heather; Johnson, Nancy; Johnson, Kathleen; Johnson, Keith A.; Johnson, Sterling; Kachaturian, Zaven; Karlawish, Jason H.; Kataki, Maria; Kaye, Jeffrey; Kertesz, Andrew; Killiany, Ronald; Kittur, Smita; Koeppe, Robert A.; Korecka, Magdalena; Kornak, John; Kozauer, Nicholas; Lah, James J.; Laubinger, Mary M.; Lee, Virginia M.-Y.; Lee, T.-Y.; Lerner, Alan; Levey, Allan I.; Longmire, Crystal Flynn; Lopez, Oscar L.; Lord, Joanne L.; Lu, Po H.; MacAvoy, Martha G.; Malloy, Paul; Marson, Daniel; Martin-Cook, Kristen; Martinez, Walter; Marzloff, George; Mathis, Chet; Mc-Adams-Ortiz, Catherine; Mesulam, Marsel; Miller, Bruce L.; Mintun, Mark A.; Mintzer, Jacobo; Molchan, Susan; Montine, Tom; Morris, John; Mulnard, Ruth A.; Munic, Donna; Nair, Anil; Neu, Scott; Nguyen, Dana; Norbash, Alexander; Oakley, MaryAnn; Obisesan, Thomas O.; Ogrocki, Paula; Ott, Brian R.; Parfitt, Francine; Pawluczyk, Sonia; Pearlson, Godfrey; Petersen, Ronald; Petrella, Jeffrey R.; Potkin, Steven; Potter, William Z.; Preda, Adrian; Quinn, Joseph; Rainka, Michelle; Reeder, Stephanie; Reiman, Eric M.; Rentz, Dorene M.; Reynolds, Brigid; Richard, Jennifer; Roberts, Peggy; Rogers, John; Rosen, Allyson; Rosen, Howard J.; Rusinek, Henry; Sabbagh, Marwan; Sadowsky, Carl; Salloway, Stephen; Santulli, Robert B.; Saykin, Andrew J.; Scharre, Douglas W.; Schneider, Lon; Schneider, Stacy; Schuff, Norbert; Shah, Raj C.; Shaw, Les; Shen, Li; Silverman, Daniel H.S.; Simpson, Donna M.; Sink, Kaycee M.; Smith, Charles D.; Snyder, Peter J.; Spann, Bryan M.; Sperling, Reisa A.; Spicer, Kenneth; Stefanovic, Bojana; Stern, Yaakov; Stopa, Edward; Tang, Cheuk; Tariot, Pierre; Taylor-Reinwald, Lisa; Thai, Gaby; Thomas, Ronald G.; Thompson, Paul; Tinklenberg, Jared; Toga, Arthur W.; Tremont, Geoffrey; Trojanowki, J.Q.; Trost, Dick; Turner, Raymond Scott; van Dyck, Christopher H.; Vanderswag, Helen; Varon, Daniel; Villanueva-Meyer, Javier; Villena, Teresa; Walter, Sarah; Wang, Paul; Watkins, Franklin; Weiner, Michael; Williamson, Jeff D.; Wolk, David; Wu, Chuang-Kuo; Zerrate, Maria; Zimmerman., Earl A.

    2010-01-01

    The ε4 allele of the apolipoprotein E (APOE) gene is the major genetic risk factor for Alzheimer’s disease (AD), but limited work has suggested that APOE genotype may modulate disease phenotype. Carriers of the ε4 allele have been reported to have greater medial temporal lobe (MTL) pathology and poorer memory than noncarriers. Less attention has focused on whether there are domains of cognition and neuroanatomical regions more affected in noncarriers. Further, a major potential confound of prior in vivo studies is the possibility of different rates of clinical misdiagnosis for carriers vs. noncarriers. We compared phenotypic differences in cognition and topography of regional cortical atrophy of ε4 carriers (n = 67) vs. noncarriers (n = 24) with mild AD from the Alzheimer’s Disease Neuroimaging Initiative, restricted to those with a cerebrospinal fluid (CSF) molecular profile consistent with AD. Between-group comparisons were made for psychometric tests and morphometric measures of cortical thickness and hippocampal volume. Carriers displayed significantly greater impairment on measures of memory retention, whereas noncarriers were more impaired on tests of working memory, executive control, and lexical access. Consistent with this cognitive dissociation, carriers exhibited greater MTL atrophy, whereas noncarriers had greater frontoparietal atrophy. Performance deficits in particular cognitive domains were associated with disproportionate regional brain atrophy within nodes of cortical networks thought to subserve these cognitive processes. These convergent cognitive and neuroanatomic findings in individuals with a CSF molecular profile consistent with AD support the hypothesis that APOE genotype modulates the clinical phenotype of AD through influence on specific large-scale brain networks. PMID:20479234

  4. Source analysis of spontaneous magnetoencephalograpic activity in healthy aging and mild cognitive impairment: influence of apolipoprotein E polymorphism.

    PubMed

    Cuesta, Pablo; Barabash, Ana; Aurtenetxe, Sara; Garcés, Pilar; López, María Eugenia; Bajo, Ricardo; Llanero-Luque, Marcos; Ancín, Inés; Cabranes, José Antonio; Marcos, Alberto; Sancho, Miguel; Nakamura, Akinori; Maestú, Fernando; Fernandez, Alberto

    2015-01-01

    The apolipoprotein E (APOE) ε4 allele is a genetic risk factor for the development of late-onset Alzheimer's disease (AD), which affects cholinergic system functioning. The association between reduced cholinergic levels and increase of magnetoencephalographic (MEG) low-frequency has been used to explain spectral changes found in AD patients. However, the investigation in predementia stages is scarce. We obtained MEG recordings from 25 aged controls and 36 mild cognitive impairment (MCI) patients during a resting-state condition. According to their APOE genotype, MCIs and controls were subdivided in carriers and non-carriers of the ε4 allele. Sources of spectral variations in these groups were calculated through beamforming. MCI patients exhibited a significant increase of relative power within the low-frequency domain, accompanied by a power decrease within the high-frequency range. APOEε4 carriers showed an increased relative power in the 4.5-6.5 Hz frequency range over frontal lobes. The power increase observed in controls carrying ε4 was significantly higher as compared with MCI non-carriers, while MCI carriers exhibited the highest relative power within the 4.5-6.5 Hz range. Higher power values within the low-frequency ranges correlated with a poorer cognitive performance in MCIs and controls. Our investigation demonstrates that APOEε4 affects resting-state activity to an extent that makes it more proximate to the pattern observed in early stages of AD. Therefore, a combination of genetic and neurophysiological information might help to detect MCI patients at higher risk of conversion to AD, and asymptomatic subjects at higher risk of developing a manifest cognitive deterioration.

  5. A systematic review and meta-analysis of the association between the apolipoprotein E genotype and delirium.

    PubMed

    Adamis, Dimitrios; Meagher, David; Williams, John; Mulligan, Owen; McCarthy, Geraldine

    2016-04-01

    The role of apolipoprotein E (APOE) in Alzheimer's disease and other dementias has been investigated intensively. However, the relationship between APOE and delirium has only recently been explored in studies that have included relatively small samples. A meta-analysis of the published pooled data is timely to explore the relationship between APOE and delirium and to inform further research in this topic. PubMed, EBSCOhost, Google Scholar, Scopus, all EBM Reviews (OVID) and the Cochrane Database of Systematic Reviews were searched with relevant keywords and from the references of relevant papers. Ten papers were found that examined the relationship between APOE and delirium. Data were extracted from eight of them and pooled for meta-analysis using random effects with R software. Data from 1762 participants, of whom 479 (27.2%) were diagnosed with delirium, showed low heterogeneity (Q=13.11, d.f.=7, P=0.07; I=44.86%). The possession of the APOE ε4 allele has a small (log odds ratio: 0.18, 95% confidence interval: 0.23-0.59), nonsignificant (P=0.38) effect on the presence of delirium. No publication bias was identified. The metapower of the pooled data was low (α=0.05, power=0.65). On analysing the studies to date, it seems that there is no association between APOE and the occurrence of delirium. We suggest that further studies are needed with greater number of patients to clarify any association as well as to examine for other patterns of association including relevance for subgroups of patients who develop delirium and for effects on the phenotype of delirium and the outcomes.

  6. C2238/αANP modulates apolipoprotein E through Egr-1/miR199a in vascular smooth muscle cells in vitro

    PubMed Central

    Stanzione, R; Sciarretta, S; Marchitti, S; Bianchi, F; Di Castro, S; Scarpino, S; Cotugno, M; Frati, G; Volpe, M; Rubattu, S

    2015-01-01

    Subjects carrying the T2238C ANP gene variant have a higher risk to suffer a stroke or myocardial infarction. The mechanisms through which T2238C/αANP exerts detrimental vascular effects need to be fully clarified. In the present work we aimed at exploring the impact of C2238/αANP (mutant form) on atherosclerosis-related pathways. As a first step, an atherosclerosis gene expression macroarray analysis was performed in vascular smooth muscle cells (VSMCs) exposed to either T2238/αANP (wild type) or C2238/αANP. The major finding was that apolipoprotein E (ApoE) gene expression was significantly downregulated by C2238/αANP and it was upregulated by T2238/αANP. We subsequently found that C2238/αANP induces ApoE downregulation through type C natriuretic peptide receptor (NPR-C)-dependent mechanisms involving the upregulation of miR199a-3p and miR199a-5p and the downregulation of DNAJA4. In fact, NPR-C knockdown rescued ApoE level. Upregulation of miR199a by NPR-C was mediated by a reactive oxygen species-dependent increase of the early growth response protein-1 (Egr-1) transcription factor. In fact, Egr-1 knockdown abolished the impact of C2238/αANP on ApoE and miR199a. Of note, downregulation of ApoE by C2238/αANP was associated with a significant increase in inflammation, apoptosis and necrosis that was completely rescued by the exogenous administration of recombinant ApoE. In conclusion, our study dissected a novel mechanism of vascular damage exerted by C2238/αANP that is mediated by ApoE downregulation. We provide the first demonstration that C2238/αANP downregulates ApoE in VSMCs through NPR-C-dependent activation of Egr-1 and the consequent upregulation of miR199a. Restoring ApoE levels could represent a potential therapeutic strategy to counteract the harmful effects of C2238/αANP. PMID:26720342

  7. C2238/αANP modulates apolipoprotein E through Egr-1/miR199a in vascular smooth muscle cells in vitro.

    PubMed

    Stanzione, R; Sciarretta, S; Marchitti, S; Bianchi, F; Di Castro, S; Scarpino, S; Cotugno, M; Frati, G; Volpe, M; Rubattu, S

    2015-01-01

    Subjects carrying the T2238C ANP gene variant have a higher risk to suffer a stroke or myocardial infarction. The mechanisms through which T2238C/αANP exerts detrimental vascular effects need to be fully clarified. In the present work we aimed at exploring the impact of C2238/αANP (mutant form) on atherosclerosis-related pathways. As a first step, an atherosclerosis gene expression macroarray analysis was performed in vascular smooth muscle cells (VSMCs) exposed to either T2238/αANP (wild type) or C2238/αANP. The major finding was that apolipoprotein E (ApoE) gene expression was significantly downregulated by C2238/αANP and it was upregulated by T2238/αANP. We subsequently found that C2238/αANP induces ApoE downregulation through type C natriuretic peptide receptor (NPR-C)-dependent mechanisms involving the upregulation of miR199a-3p and miR199a-5p and the downregulation of DNAJA4. In fact, NPR-C knockdown rescued ApoE level. Upregulation of miR199a by NPR-C was mediated by a reactive oxygen species-dependent increase of the early growth response protein-1 (Egr-1) transcription factor. In fact, Egr-1 knockdown abolished the impact of C2238/αANP on ApoE and miR199a. Of note, downregulation of ApoE by C2238/αANP was associated with a significant increase in inflammation, apoptosis and necrosis that was completely rescued by the exogenous administration of recombinant ApoE. In conclusion, our study dissected a novel mechanism of vascular damage exerted by C2238/αANP that is mediated by ApoE downregulation. We provide the first demonstration that C2238/αANP downregulates ApoE in VSMCs through NPR-C-dependent activation of Egr-1 and the consequent upregulation of miR199a. Restoring ApoE levels could represent a potential therapeutic strategy to counteract the harmful effects of C2238/αANP. PMID:26720342

  8. The intravenous injection of oxidized LDL- or Apolipoprotein B100 – Coupled splenocytes promotes Th1 polarization in wildtype and Apolipoprotein E – Deficient mice

    SciTech Connect

    Steinmetz, Martin; Ponnuswamy, Padmapriya; Laurans, Ludivine; Esposito, Bruno; Tedgui, Alain; Mallat, Ziad

    2015-08-14

    Background: Th1 responses in atherosclerosis are mainly associated with the aggravation of atherosclerotic plaques, whereas Th2 responses lead to a less pronounced disease in mouse models. The fixation of antigens on cells by means of ethylene carbodiimide (ECDI), and subsequent injection of these antigen-coupled splenocytes (Ag-SP) to induce tolerance against the attached antigens, has been successfully used to treat murine type 1 diabetes or encephalomyelitis in. We analyzed this approach in a mouse model for atherosclerosis. Methods and results: OTII-transgenic mice that were treated with a single dose of 5 × 10{sup 7} OVA-coupled splenocytes (OVA-SP), had decreased splenocyte proliferation, and lower IFNγ production in vitro upon antigen recall. However, in vivo CD4 cell activation was increased. To try lipoprotein-derived, “atherosclerosis-associated” antigens, we first tested human oxidized LDL. In wild type mice, an increase of IFNγ production upon in vitro recall was detected in the oxLDL-SP group. In Apolipoprotein E − deficient (ApoE−/−) mice that received oxLDL-SP every 5 weeks for 20 weeks, we did not find any difference of atherosclerotic plaque burden, but again increased IFNγ production. To overcome xenogenous limitations, we then examined the effects of mouse Apolipoprotein B100 peptides P3 and P6. ApoB100-SP treatment again promoted a more IFNγ pronounced response upon in vitro recall. Flow cytometry analysis of cytokine secreting spleen cells revealed CD4 positive T cells to be mainly the source for IFNγ. In ApoE−/− mice that were administered ApoB100-SP during 20 weeks, the atherosclerotic plaque burden in aortic roots as well as total aorta was unchanged compared to PBS treated controls. Splenocyte proliferation upon antigen recall was not significantly altered in ApoB100-SP treated ApoE−/− mice. Conclusion: Although we did not observe a relevant anti-atherosclerotic benefit, the treatment with antigen

  9. Production of recombinant orange-spotted grouper (Epinephelus coioides) follicle-stimulating hormone (FSH) in single-chain form and dimer form by Pichia pastoris and their biological activities.

    PubMed

    Chen, Jun; Zhang, Yanhong; Tang, Zhiguo; Mao, Jiewei; Kuang, Zhonglei; Qin, Chaobin; Li, Wensheng

    2012-09-01

    FSH is a key regulator of steroidogenesis and gonadal growth in teleosts. However, function of FSH is elusive in grouper due to the lack of purified and native FSH. In the present study, we reported production of bioactive orange-spotted grouper (Epinephelus coioides) FSH in dimer form and single-chain form by Pichia pastoris. Dimer form of recombinant grouper FSH (rgFSHba) was accomplished by co-expressing mature FSHb-subunit and a-subunit genes. Fusion of mature FSHb-subunit and a-subunit genes together linking with a polypeptide (4×(Gly-Ser)-Gly-Thr) gene generated single-chain form of recombinant grouper FSH (rgFSHb-a). Recombinant grouper common α-subunit (rgCga) and FSHb-subunit (rgFSHb) were also separately produced. Recombinant proteins were verified by Western blot and mass spectrometry assays, and characterized by deglycosylation analysis. Deglycosylation assay suggested that glycosylation of recombinant FSH mainly occurred on common a-subunit. Bioactivities of recombinant proteins were initially evaluated by activating grouper FSH receptor, and further demonstrated by incubating ovarian fragments of adult grouper and intraperitoneal injection in juvenile female grouper. Two forms of recombinant FSH presented similar biological activities of activating FSH receptor and stimulating in vitro testosterone (T) and estradiol-17β (E2) secretion, though the dimer form functioned slightly weaker than the single-chain form. However, injections of rgFSHb-a or rgFSHba could significantly increase serum T and E2 levels, induce early ovarian development, reduce hypothalamic gnrh1 mRNA level, and increase hypothalamic cyp19a1b mRNA level. Data in this study suggested that recombinant gonadotropin could be produced in dimer form or single-chain form by P. pastoris, and FSH could regulate steroidogenesis and early ovarian development in juvenile grouper.

  10. Crystal Structure of a Human Single Domain Antibody Dimer Formed through VH-VH Non-Covalent Interactions

    PubMed Central

    Li, Shenghua; Tanha, Jamshid; Arbabi-Ghahroudi, Mehdi; Zhang, Jianbing; Wang, Shuying

    2012-01-01

    Single-domain antibodies (sdAbs) derived from human VH are considered to be less soluble and prone to aggregate which makes it difficult to determine the crystal structures. In this study, we isolated and characterized two anti-human epidermal growth factor receptor-2 (HER2) sdAbs, Gr3 and Gr6, from a synthetic human VH phage display library. Size exclusion chromatography and surface plasmon resonance analyses demonstrated that Gr3 is a monomer, but that Gr6 is a strict dimer. To understand this different molecular behavior, we solved the crystal structure of Gr6 to 1.6 Å resolution. The crystal structure revealed that the homodimer assembly of Gr6 closely mimics the VH-VL heterodimer of immunoglobulin variable domains and the dimerization interface is dominated by hydrophobic interactions. PMID:22253912

  11. Familial apolipoprotein E deficiency.

    PubMed Central

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

    1986-01-01

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

  12. Chronic treatment with angiotensin-(1-7) improves renal endothelial dysfunction in apolipoproteinE-deficient mice

    PubMed Central

    Stegbauer, J; Potthoff, SA; Quack, I; Mergia, E; Clasen, T; Friedrich, S; Vonend, O; Woznowski, M; Königshausen, E; Sellin, L; Rump, LC

    2011-01-01

    BACKGROUND AND PURPOSE ApolipoproteinE-deficient [apoE (−/−)] mice, a model of human atherosclerosis, develop endothelial dysfunction caused by decreased levels of nitric oxide (NO). The endogenous peptide, angiotensin-(1-7) [Ang-(1-7)], acting through its specific GPCR, the Mas receptor, has endothelium-dependent vasodilator properties. Here we have investigated if chronic treatment with Ang-(1-7) improved endothelial dysfunction in apoE (−/−) mice. EXPERIMENTAL APPROACH ApoE (−/−) mice fed on a lipid-rich Western diet were divided into three groups and treated via osmotic minipumps with either saline, Ang-(1-7) (82 µg·kg−1·h−1) or the same dose of Ang-(1-7) together with D-Ala-Ang-(1-7) (125 µg·kg−1·h−1) for 6 weeks. Renal vascular function was assessed in isolated perfused kidneys. KEY RESULTS Ang-(1-7)-treated apoE (−/−) mice showed improved renal endothelium-dependent vasorelaxation induced by carbachol and increased renal basal cGMP production, compared with untreated apoE (−/−) mice. Tempol, a reactive oxygen species (ROS) scavenger, improved endothelium-dependent vasorelaxation in kidneys of saline-treated apoE (−/−) mice whereas no effect was observed in Ang-(1-7)-treated mice. Chronic treatment with D-Ala-Ang-(1-7), a specific Mas receptor antagonist, abolished the beneficial effects of Ang-(1-7) on endothelium-dependent vasorelaxation. Renal endothelium-independent vasorelaxation showed no differences between treated and untreated mice. ROS production and expression levels of the NAD(P)H oxidase subunits gp91phox and p47phox were reduced in isolated preglomerular arterioles of Ang-(1-7)-treated mice, compared with untreated mice, whereas eNOS expression was increased. CONCLUSION AND IMPLICATIONS Chronic infusion of Ang-(1-7) improved renal endothelial function via Mas receptors, in an experimental model of human cardiovascular disease, by increasing levels of endogenous NO. PMID:21371005

  13. Acrolein Modification Impairs Key Functional Features of Rat Apolipoprotein E: Identification of Modified Sites by Mass Spectrometry

    PubMed Central

    Tran, Tuyen N.; Kosaraju, Malathi G.; Tamamizu-Kato, Shiori; Akintunde, Olayemi; Zheng, Ying; Bielicki, John K.; Pinkerton, Kent; Uchida, Koji; Lee, Yuan Yu; Narayanaswami, Vasanthy

    2014-01-01

    Apolipoprotein E (apoE), an anti-atherogenic apolipoprotein, plays a significant role in the metabolism of lipoproteins. It lowers plasma lipid levels by acting as a ligand for low-density lipoprotein receptor (LDLr) family of proteins, in addition to playing a role in promoting macrophage cholesterol efflux in atherosclerotic lesions. The objective of this study is to examine the effect of acrolein modification on the structure and function of rat apoE and to determine sites and nature of modification by mass spectrometry. Acrolein is a highly reactive aldehyde, which is generated endogenously as one of the products of lipid peroxidation and is present in the environment in pollutants such as tobacco smoke and heated oils. In initial studies, acrolein-modified apoE was identified by immunoprecipitation using an acrolein-lysine specific antibody, in the plasma of ten-week old male rats that were exposed to filtered air (FA) or low doses of environmental tobacco smoke (ETS). While both groups displayed acrolein-modified apoE in the lipoprotein fraction, the ETS group had higher levels in lipid-free fraction compared to the FA group. This observation provided the rationale to further investigate the effect of acrolein modification on rat apoE at a molecular level. Treatment of recombinant rat apoE with a 10-fold molar excess of acrolein resulted in: (i) a significant decrease in lipid-binding and cholesterol efflux abilities, (ii) impairment in the LDLr- and heparin-binding capabilities, and (iii) significant alterations in the overall stability of the protein. The disruption in the functional abilities is attributed directly or indirectly to acrolein modification yielding: an aldimine adduct at K149 and K155 (+38); a propanal adduct at K135 and K138 (+56); an Nε-(3-methylpyridinium)lysine (MP-lysine) at K64, K67 and K254 (+76), and Nε-(3-formyl-3,4-dehydropiperidino)lysine (FDP-lysine) derivative at position K68 (+94), as determined by Matrix-Assisted Laser

  14. Polychlorinated biphenyl 77 augments angiotensin II-induced atherosclerosis and abdominal aortic aneurysms in male apolipoprotein E deficient mice

    SciTech Connect

    Arsenescu, Violeta; Arsenescu, Razvan; Parulkar, Madhura; Karounos, Michael; Zhang, Xuan; Baker, Nicki; Cassis, Lisa A.

    2011-11-15

    Infusion of angiotensin II (AngII) to hyperlipidemic mice augments atherosclerosis and causes formation of abdominal aortic aneurysms (AAAs). Each of these AngII-induced vascular pathologies exhibit pronounced inflammation. Previous studies demonstrated that coplanar polychlorinated biphenyls (PCBs) promote inflammation in endothelial cells and adipocytes, two cell types implicated in AngII-induced vascular pathologies. The purpose of this study was to test the hypothesis that administration of PCB77 to male apolipoprotein E (ApoE) -/- mice promotes AngII-induced atherosclerosis and AAA formation. Male ApoE-/- mice were administered vehicle or PCB77 (49 mg/kg, i.p.) during week 1 and 4 (2 divided doses/week) of AngII infusion. Body weights and total serum cholesterol concentrations were not influenced by administration of PCB77. Systolic blood pressure was increased in AngII-infused mice administered PCB77 compared to vehicle (156 {+-} 6 vs 137 {+-} 5 mmHg, respectively). The percentage of aortic arch covered by atherosclerotic lesions was increased in AngII-infused mice administered PCB77 compared to vehicle (2.0 {+-} 0.4 vs 0.9 {+-} 0.1%, respectively). Lumen diameters of abdominal aortas determined by in vivo ultrasound and external diameters of excised suprarenal aortas were increased in AngII-infused mice administered PCB77 compared to vehicle. In addition, AAA incidence increased from 47 to 85% in AngII-infused mice administered PCB77. Adipose tissue in close proximity to AAAs from mice administered PCB77 exhibited increased mRNA abundance of proinflammatory cytokines and elevated expression of components of the renin-angiotensin system (angiotensinogen, angiotensin type 1a receptor (AT1aR)). These results demonstrate that PCB77 augments AngII-induced atherosclerosis and AAA formation. -- Highlights: Black-Right-Pointing-Pointer Polychlorinated biphenyl 77 (PCB77) promotes AngII-induced hypertension. Black-Right-Pointing-Pointer PCB77 augments Ang

  15. Apolipoprotein E Likely Contributes to a Maturation Step of Infectious Hepatitis C Virus Particles and Interacts with Viral Envelope Glycoproteins

    PubMed Central

    Lee, Ji-Young; Acosta, Eliana G.; Stoeck, Ina Karen; Long, Gang; Hiet, Marie-Sophie; Mueller, Birthe; Fackler, Oliver T.; Kallis, Stephanie

    2014-01-01

    ABSTRACT The assembly of infectious hepatitis C virus (HCV) particles is tightly linked to components of the very-low-density lipoprotein (VLDL) pathway. We and others have shown that apolipoprotein E (ApoE) plays a major role in production of infectious HCV particles. However, the mechanism by which ApoE contributes to virion assembly/release and how it gets associated with the HCV particle is poorly understood. We found that knockdown of ApoE reduces titers of infectious intra- and extracellular HCV but not of the related dengue virus. ApoE depletion also reduced amounts of extracellular HCV core protein without affecting intracellular core amounts. Moreover, we found that ApoE depletion affected neither formation of nucleocapsids nor their envelopment, suggesting that ApoE acts at a late step of assembly, such as particle maturation and infectivity. Importantly, we demonstrate that ApoE interacts with the HCV envelope glycoproteins, most notably E2. This interaction did not require any other viral proteins and depended on the transmembrane domain of E2 that also was required for recruitment of HCV envelope glycoproteins to detergent-resistant membrane fractions. These results suggest that ApoE plays an important role in HCV particle maturation, presumably by direct interaction with viral envelope glycoproteins. IMPORTANCE The HCV replication cycle is tightly linked to host cell lipid pathways and components. This is best illustrated by the dependency of HCV assembly on lipid droplets and the VLDL component ApoE. Although the role of ApoE for production of infectious HCV particles is well established, it is still poorly understood how ApoE contributes to virion formation and how it gets associated with HCV particles. Here, we provide experimental evidence that ApoE likely is required for an intracellular maturation step of HCV particles. Moreover, we demonstrate that ApoE associates with the viral envelope glycoproteins. This interaction appears to be dispensable

  16. Apolipoprotein E-knockout mice show increased titers of serum anti-nuclear and anti-dsDNA antibodies

    SciTech Connect

    Wang, Yuehai; Huang, Ziyang; Lu, Huixia; Lin, Huili; Wang, Zhenhua; Chen, Xiaoqing; Ouyang, Qiufang; Tang, Mengxiong; Hao, Panpan; Ni, Jingqin; Xu, Dongming; Zhang, Mingxiang; Zhang, Qunye; Lin, Ling; and others

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer Titers of ANA and anti-dsDNA antibodies were higher in ApoE{sup -/-} than C57B6/L mice. Black-Right-Pointing-Pointer Spleen was greater and splenocyte apoptosis lower in ApoE{sup -/-} than B6 mice. Black-Right-Pointing-Pointer Level of TLR4 was lower in spleen tissue of ApoE{sup -/-} than B6 mice. Black-Right-Pointing-Pointer The TLR4 pathway may participate in maintaining the balance of splenocyte apoptosis. Black-Right-Pointing-Pointer The TLR4 pathway may participate in antibody production in spleen tissue. -- Abstract: Apolipoprotein E-knockout (ApoE{sup -/-}) mice, atherosclerosis-prone mice, show an autoimmune response, but the pathogenesis is not fully understood. We investigated the pathogenesis in female and male ApoE{sup -/-} mice. The spleens of all ApoE{sup -/-} and C57BL/6 (B6) mice were weighed. The serum IgG level and titers of anti-nuclear antibody (ANA) and anti-double-stranded DNA (anti-dsDNA) antibody were assayed by ELISA. Apoptosis of spleen tissue was evaluated by TUNEL. TLR4 level in spleen tissue was tested by immunohistochemistry and Western blot analysis. Levels of MyD88, p38, phosphorylated p38 (pp38), interferon regulatory factor 3 (IRF3) and Bcl-2-associated X protein (Bax) in spleen tissue were detected by Western blot analysis. We also survey the changes of serum autoantibodies, spleen weight, splenocyte apoptosis and the expressions of TLR4, MyD88, pp38, IRF3 and Bax in spleen tissue in male ApoE{sup -/-} mice after 4 weeks of lipopolysaccharide (LPS), Toll-like receptor 4 ligand, administration. ApoE{sup -/-} mice showed splenomegaly and significantly increased serum level of IgG and titers of ANA and anti-dsDNA antibody as compared with B6 mice. Splenocyte apoptosis and the expression of TLR4, MyD88, pp38, IRF3 and Bax in spleen tissue were significantly lower in ApoE{sup -/-} than B6 mice. The expression of TLR4, MyD88, IRF3, pp38, and Bax differed by sex in ApoE{sup -/-} spleen tissue. The

  17. Acrolein modification impairs key functional features of rat apolipoprotein E: identification of modified sites by mass spectrometry.

    PubMed

    Tran, Tuyen N; Kosaraju, Malathi G; Tamamizu-Kato, Shiori; Akintunde, Olayemi; Zheng, Ying; Bielicki, John K; Pinkerton, Kent; Uchida, Koji; Lee, Yuan Yu; Narayanaswami, Vasanthy

    2014-01-21

    Apolipoprotein E (apoE), an antiatherogenic apolipoprotein, plays a significant role in the metabolism of lipoproteins. It lowers plasma lipid levels by acting as a ligand for the low-density lipoprotein receptor (LDLr) family of proteins, in addition to playing a role in promoting macrophage cholesterol efflux in atherosclerotic lesions. The objective of this study is to examine the effect of acrolein modification on the structure and function of rat apoE and to determine the sites and nature of modification by mass spectrometry. Acrolein is a highly reactive aldehyde, which is generated endogenously as one of the products of lipid peroxidation and is present in the environment in pollutants such as tobacco smoke and heated oils. In initial studies, acrolein-modified apoE was identified by immunoprecipitation using an acrolein-lysine specific antibody in the plasma of 10-week old male rats that were exposed to filtered air (FA) or low doses of environmental tobacco smoke (ETS). While both groups displayed acrolein-modified apoE in the lipoprotein fraction, the ETS group had higher levels in the lipid-free fraction compared with the FA group. This observation provided the rationale to further investigate the effect of acrolein modification on rat apoE at a molecular level. Treatment of recombinant rat apoE with a 10-fold molar excess of acrolein resulted in (i) a significant decrease in lipid-binding and cholesterol efflux abilities, (ii) impairment in the LDLr- and heparin-binding capabilities, and (iii) significant alterations in the overall stability of the protein. The disruption in the functional abilities is attributed directly or indirectly to acrolein modification yielding an aldimine adduct at K149 and K155 (+38); a propanal adduct at K135 and K138 (+56); an N(ε)-(3-methylpyridinium)lysine (MP-lysine) at K64, K67, and K254 (+76), and an N(ε)-(3-formyl-3,4-dehydropiperidino)lysine (FDP-lysine) derivative at position K68 (+94), as determined by matrix

  18. Association between amylin and amyloid-β peptides in plasma in the context of apolipoprotein E4 allele.

    PubMed

    Qiu, Wei Qiao; Wallack, Max; Dean, Michael; Liebson, Elizabeth; Mwamburi, Mkaya; Zhu, Haihao

    2014-01-01

    Amylin, a pancreatic peptide that readily crosses the blood brain barrier (BBB), and amyloid-beta peptide (Aβ), the main component of amyloid plaques and a major component of Alzheimer's disease (AD) pathology in the brain, share several features. These include having similar β-sheet secondary structures, binding to the same receptor, and being degraded by the same protease. Thus, amylin may be associated with Aβ, but the nature of their relationship remains unclear. In this study, we used human samples to study the relationship between plasma amylin and Aβ in the context of the apolipoprotein E alleles (ApoE). We found that concentrations of Aβ1-42 (P<0.0001) and Aβ1-40 (P<0.0001) increased with each quartile increase of amylin. Using multivariate regression analysis, the study sample showed that plasma amylin was associated with Aβ1-42 (β = +0.149, SE = 0.025, P<0.0001) and Aβ1-40 (β = +0.034, SE = 0.016, P = 0.04) as an outcome after adjusting for age, gender, ethnicity, ApoE4, BMI, diabetes, stroke, kidney function and lipid profile. This positive association between amylin and Aβ1-42 in plasma was found regardless of the ApoE genotype. In contrast, the relationship between amylin and Aβ1-40 in plasma seen in ApoE4 non-carriers disappeared in the presence of ApoE4. Using AD mouse models, our recent study demonstrates that intraperitoneal (i.p.) injection of synthetic amylin enhances the removal of Aβ from the brain into blood, thus resulting in increased blood levels of both amylin and Aβ. The positive association between amylin and Aβ, especially Aβ1-42, in human blood samples is probably relevant to the findings in the AD mouse models. The presence of ApoE4 may attenuate amylin's capacity to remove Aβ, especially Aβ1-40, from the AD brain.

  19. Chick heat-shock protein of Mr = 90,000, free or released from progesterone receptor, is in a dimeric form.

    PubMed

    Radanyi, C; Renoir, J M; Sabbah, M; Baulieu, E E

    1989-02-15

    A monoclonal antibody (BF4) has been used to characterize and purify the heat-shock protein of Mr approximately 90,000 (hsp 90) present in the chick oviduct. In low salt cytosol, the sedimentation coefficient of hsp 90 is approximately 6.8 S, the Stokes radius approximately 7.1 nm, and the calculated Mr approximately 204,000, thus suggesting a dimeric structure. In 0.4 M KCl cytosol, only slightly smaller values were determined (approximately 6.5 S, approximately 6.8 nm, and approximately 187,000). Following purification by ion exchange and immunoaffinity chromatography, hsp 90 migrated as a single silver-stained band at Mr approximately 90,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, while the sedimentation coefficient 6.2 S, the Stokes radius approximately 6.8 nm, and the Mr approximately 178,000 confirmed the dimeric structure. However, in both antigen or antibody excess conditions, only one molecule of monoclonal antibody could be bound to the hsp 90 dimer. Whether steric hindrance in a homodimer or the presence of two different 90-kDa proteins in a heterodimer explains this result cannot yet be decided. The dimer is not dissociated by high salt (1 M KCl) or the chaotropic agent (0.5 M NaSCN), but is disrupted by 4 M urea, suggesting a stabilization of the structure by hydrogen bonds. The molybdate-stabilized progesterone receptor hetero-oligomer form of approximately 8 S sedimentation coefficient was purified, and its hsp 90 component was then released by salt treatment. It was found to sediment at approximately 5.8 S and have a Stokes radius approximately 7.1 nm, giving Mr approximately 174,000. This observation is consistent with a previous report suggesting from specific activity determination, scanning of polyacrylamide gels, and cross-linking experiments that each purified nontransformed progesterone receptor molecule includes one progesterone binding unit per two 90-kDa protein molecules (Renoir, J. M., Buchou, T., Mester, J

  20. Cannabidiol-2',6'-dimethyl ether stimulates body weight gain in apolipoprotein E-deficient BALB/c. KOR/Stm Slc-Apoe(shl) mice.

    PubMed

    Takeda, Shuso; Hirota, Rena; Teradaira, Sari; Takeda-Imoto, Masumi; Watanabe, Kazuhito; Toda, Akihisa; Aramaki, Hironori

    2015-12-01

    The biological activities of cannabidiol (CBD), a major non-psychotropic constituent of the fiber-type cannabis plant, have been examined in detail (e.g., CBD modulation of body weight in mice and rats). However, few studies have investigated the biological activities of cannabidiol-2',6'-dimethyl ether (CBDD), a dimethyl ether derivative of the parent CBD. We herein focused on the effects of CBDD on body weight changes in mice, and demonstrated that it stimulated body weight gain in apolipoprotein E (ApoE)-deficient BALB/c. KOR/Stm Slc-Apoe(shl) mice, especially between 10 and 20 weeks of age.

  1. Cold inactivation and dissociation into dimers of Escherichia coli tryptophanase and its W330F mutant form.

    PubMed

    Erez, T; Gdalevsky GYa; Torchinsky, Y M; Phillips, R S; Parola, A H

    1998-05-19

    The kinetics and mechanism of reversible cold inactivation of the tetrameric enzyme tryptophanase have been studied. Cold inactivation is shown to occur slowly in the presence of K+ ions and much faster in their absence. The W330F mutant tryptophanase undergoes rapid cold inactivation even in the presence of K+ ions. In all cases the inactivation is accompanied by a decrease of the coenzyme 420-nm CD and absorption peaks and a shift of the latter peak to shorter wavelengths. The spectral changes and the NaBH4 test indicate that cooling of tryptophanase leads to breaking of the internal aldimine bond and release of the coenzyme. HPLC analysis showed that the ensuing apoenzyme dissociates into dimers. The dissociation depends on the nature and concentration of anions in the buffer solution. It readily occurs at low protein concentrations in the presence of salting-in anions Cl-, NO3- and I-, whereas salting-out anions, especially HPO4(2-), hinder the dissociation. K+ ions do not influence the dissociation of the apoenzyme, but partially protect holotryptophanase from cold inactivation. Thus, the two processes, cold inactivation of tryptophanase and dissociation of its apoform into dimers exhibit different dependencies on K+ ions and anions.

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

    PubMed

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

    2011-04-01

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

  3. Multiple, diverse senile plaque-associated proteins are ligands of an apolipoprotein E receptor, the alpha 2-macroglobulin receptor/low-density-lipoprotein receptor-related protein.

    PubMed

    Rebeck, G W; Harr, S D; Strickland, D K; Hyman, B T

    1995-02-01

    Both apolipoprotein E and its receptor, the low-density-lipoprotein receptor-related protein (LRP), are associated with senile plaques in Alzheimer's disease. We examined the relationship of other LRP-related molecules to senile plaques. LRP is a multifunctional receptor that binds and rapidly internalizes at least seven ligands: apolipoprotein E, activated alpha 2-macroglobulin, tissue and urokinase-type plasminogen activators, plasminogen activator inhibitor-1, lipoprotein lipase, and lactoferrin. Using immunohistochemistry, we showed that all of these ligands, representing a diverse group of otherwise apparently unrelated proteins, accumulate on senile plaques. We also studied expression of the receptor-associated protein, a physiological inhibitor of LRP, in the hippocampal formation from normal subjects and Alzheimer's disease patients. Receptor-associated protein colocalizes with LRP on neuronal soma, but not on neuronal processes or reactive astrocytes. It is not present on senile plaques. These results suggest that senile plaque-associated LRP can bind its ligands, but clearance of these compounds may be impaired in the vicinity of senile plaques.

  4. Redesigning the procaspase-8 dimer interface for improved dimerization

    PubMed Central

    Ma, Chunxiao; MacKenzie, Sarah H; Clay Clark, A

    2014-01-01

    Caspase-8 is a cysteine directed aspartate-specific protease that is activated at the cytosolic face of the cell membrane upon receptor ligation. A key step in the activation of caspase-8 depends on adaptor-induced dimerization of procaspase-8 monomers. Dimerization is followed by limited autoproteolysis within the intersubunit linker (IL), which separates the large and small subunits of the catalytic domain. Although cleavage of the IL stabilizes the dimer, the uncleaved procaspase-8 dimer is sufficiently active to initiate apoptosis, so dimerization of the zymogen is an important mechanism to control apoptosis. In contrast, the effector caspase-3 is a stable dimer under physiological conditions but exhibits little enzymatic activity. The catalytic domains of caspases are structurally similar, but it is not known why procaspase-8 is a monomer while procaspase-3 is a dimer. To define the role of the dimer interface in assembly and activation of procaspase-8, we generated mutants that mimic the dimer interface of effector caspases. We show that procaspase-8 with a mutated dimer interface more readily forms dimers. Time course studies of refolding also show that the mutations accelerate dimerization. Transfection of HEK293A cells with the procaspase-8 variants, however, did not result in a significant increase in apoptosis, indicating that other factors are required in vivo. Overall, we show that redesigning the interface of procaspase-8 to remove negative design elements results in increased dimerization and activity in vitro, but increased dimerization, by itself, is not sufficient for robust activation of apoptosis. PMID:24442640

  5. A soluble form of the interleukin-6 family signal transducer gp130 is dimerized via a C-terminal disulfide bridge resulting from alternative mRNA splicing.

    PubMed

    Wolf, Janina; Waetzig, Georg H; Reinheimer, Torsten M; Scheller, Jürgen; Rose-John, Stefan; Garbers, Christoph

    2016-02-19

    Interleukin-6 (IL-6) signaling can be divided into classic signaling (via the membrane-bound IL-6 receptor, IL-6R) and trans-signaling (via the soluble IL-6R, sIL-6R), and both modes of signaling activate cells via a homodimer of the ubiquitously expressed β-receptor glycoprotein 130 (gp130). IL-6 trans-signaling is responsible for most of the pro-inflammatory activities of IL-6 and plays a role in many inflammatory diseases including inflammation-driven cancers. IL-6 trans-signaling can be selectively inhibited by soluble forms of gp130. To date, three forms of sgp130 (full-length sgp130, sgp130-RAPS and sgp130-E10) with different molecular weight have been described, which originate from alternative splicing or alternative polyadenylation of the gp130 mRNA. All these proteins are capable of blocking signaling of the IL-6/sIL-6R complex, albeit with different efficacy. The full length form of sgp130 comprises the domains D1 to D6 and a short unique C-terminus which arises from alternative splicing. In the present study, we analyze the role of a unique cysteine residue (Cys-628) within this C-terminus, which is contained neither in the membrane-bound gp130 nor in the two other sgp130 forms. Full-length sgp130 can form a disulfide-linked dimer via this cysteine residue. These natural sgp130 dimers are absent under reducing conditions or in a sgp130 C628A mutant. Although the disulfide-dimerized sgp130 represents only a small fraction of the total amount of sgp130 and, thus, may appear to be dispensable for the global inhibitory activities of sgp130 in the circulation, it may represent a further possibility to modulate gradients of sgp130 with different properties depending on the local redox potential in a cell- or tissue-dependent manner. PMID:26809098

  6. Effect of rubidium and cesium ions on the dimeric quaduplex formed by the Oxytricha nova telomeric repeat oligonucleotide d(GGGGTTTTGGGG).

    PubMed

    Marincola, Flaminia Cesare; Virno, Ada; Randazzo, Antonio; Lai, Adolfo

    2007-01-01

    The DNA sequence d(GGGGTTTTGGGG) consists of 1.5 units of the repeat in telomeres of Oxytricha nova. It has been shown by NMR and x-ray crystallographic analysis that it is capable to form a dimeric quadruplex structure and that a variety of cations, namely K(+), Na(+), and NH(4)(+), are able to interact with this complex with different affinity, leading to complexes characterized by different local conformations. Thus, in order to improve the knowledge of this kind of molecule, and in particular to provide further insight into the role of monovalent cations in the G-quadruplex folding and conformation, we have investigated by (1)H-NMR the effect of the addition of Rb(+) and Cs(+) to the quadruplex formed by the oligonucleotide d(GGGGTTTTGGGG).

  7. Modified-live infectious bovine rhinotracheitis virus vaccine expressing monomer and dimer forms of foot-and-mouth disease capsid protein epitopes on surface of hybrid virus particles.

    PubMed

    Kit, S; Kit, M; DiMarchi, R D; Little, S P; Gale, C

    1991-01-01

    Modified-live, attenuated infectious bovine rhinotracheitis (IBR) hybrid virus vaccines have been constructed by inserting in the major IBRV glycoprotein gIII gene chemically synthesized deoxyribonucleotide sequences encoding the bovine growth hormone signal sequence and monomeric or dimeric forms of the foot and mouth disease virus (FMDV) VP 1 epitope sequences. The foreign DNA sequences were inserted at the N-terminal end of the IBRV gIII coding sequence and were driven by the IBRV gIII promoter. The sequences encoding the first 38 and the first 21 amino acids of the IBRV gIII were deleted from the hybrid viruses containing inserts of the monomeric and dimeric FMDV epitope sequences, respectively, to avoid redundant signal sequences. Plaque immunoassay experiments with guinea pig and bovine anti-FMDV peptide antisera, and with anti-IBRV gIII monoclonal antibodies demonstrated that IBRV-FMDV fusion proteins were expressed in virus-infected MDBK cells. Immunoelectron microscopy analyses demonstrated that the IBRV-FMDV fusion proteins were expressed as repeated structures on the surface of virus particles. Experiments showed that the recombinant IBRV-FMDV viruses protected cattle from IBRV (Cooper) challenge and induced anti-FMDV peptide antibodies, thereby demonstrating that the FMDV epitopes were expressed in vivo. PMID:1718244

  8. Single-Molecule Analysis of Thymine Dimer-Containing G-Quadruplexes Formed from the Human Telomere Sequence

    PubMed Central

    2015-01-01

    The human telomere plays crucial roles in maintaining genome stability. In the presence of suitable cations, the repetitive 5′-TTAGGG-3′ human telomere sequence can fold into G-quadruplexes that adopt the hybrid, basket, or propeller fold. The telomere sequence is hypersensitive to UV-induced thymine dimer (T=T) formation, yet it does not cause telomere shortening. In this work, the potential structural disruption and thermodynamic stability of the T=T-containing natural telomere sequences were studied to understand why this damage is tolerated in telomeres. First, established methods, such as thermal melting measurements, electrophoretic mobility shift assays, and circular dichroism spectroscopy, were utilized to determine the effects of the damage on these structures. Second, a single-molecule ion channel recording technique using α-hemolysin (α-HL) was employed to examine further the structural differences between the damaged sequences. It was observed that the damage caused slightly lower thermal stabilities and subtle changes in the circular dichroism spectra for hybrid and basket folds. The α-HL experiments determined that T=Ts disrupt double-chain reversal loop formation but are tolerated in edgewise and diagonal loops. The largest change was observed for the T=T-containing natural telomere sequence when the propeller fold (all double-chain reversal loops) was studied. On the basis of the α-HL experiments, it was determined that a triplexlike structure exists under conditions that favor a propeller structure. The biological significance of these observations is discussed. PMID:25407781

  9. The C-terminal region of the transcriptional regulator THAP11 forms a parallel coiled-coil domain involved in protein dimerization.

    PubMed

    Cukier, Cyprian D; Maveyraud, Laurent; Saurel, Olivier; Guillet, Valérie; Milon, Alain; Gervais, Virginie

    2016-06-01

    Thanatos associated protein 11 (THAP11) is a cell cycle and cell growth regulator differentially expressed in cancer cells. THAP11 belongs to a distinct family of transcription factors recognizing specific DNA sequences via an atypical zinc finger motif and regulating diverse cellular processes. Outside the extensively characterized DNA-binding domain, THAP proteins vary in size and predicted domains, for which structural data are still lacking. We report here the crystal structure of the C-terminal region of human THAP11 protein, providing the first 3D structure of a coiled-coil motif from a THAP family member. We further investigate the stability, dynamics and oligomeric properties of the determined structure combining molecular dynamics simulations and biophysical experiments. Our results show that the C-ter region of THAP11 forms a left-handed parallel homo-dimeric coiled-coil structure possessing several unusual features. PMID:26975212

  10. Exploring the effects of the atherosclerosis progression and the choice of affected arteries in the design of experiments with Apolipoprotein E-deficient mice.

    PubMed

    Riera-Borrull, Marta; Sabench, Fàtima; del Castillo, Daniel; Camps, Jordi; Joven, Jorge

    2016-01-01

    The objective of this study is to explore the longitudinal progression of atherosclerosis and the correlation between methods to measure the lesion in apolipoprotein E-deficient mice. Atherosclerosis progression was assessed by measurements of foam cell-rich depositions in their proximal aortas, and/or in surgically excised arteries, to assess the histological luminal narrowing. A longitudinal study was performed by comparing the values for carotid, aorta, and femoral and iliac arteries using common histological techniques. There were no significant differences in progression between different arteries, but correlation with the classical measurement of atherosclerosis in the aortic root was poor. Each laboratory requires specific standardization. Carotid arteries were sensitive to atherosclerosis in these mice, and progression was exponential. In conclusion, morphometric data show the importance of the choice of the duration of treatment, the appropriate controls, and the age at which to begin the experiments. PMID:26899621

  11. Exploring the effects of the atherosclerosis progression and the choice of affected arteries in the design of experiments with Apolipoprotein E-deficient mice.

    PubMed

    Riera-Borrull, Marta; Sabench, Fàtima; del Castillo, Daniel; Camps, Jordi; Joven, Jorge

    2016-01-01

    The objective of this study is to explore the longitudinal progression of atherosclerosis and the correlation between methods to measure the lesion in apolipoprotein E-deficient mice. Atherosclerosis progression was assessed by measurements of foam cell-rich depositions in their proximal aortas, and/or in surgically excised arteries, to assess the histological luminal narrowing. A longitudinal study was performed by comparing the values for carotid, aorta, and femoral and iliac arteries using common histological techniques. There were no significant differences in progression between different arteries, but correlation with the classical measurement of atherosclerosis in the aortic root was poor. Each laboratory requires specific standardization. Carotid arteries were sensitive to atherosclerosis in these mice, and progression was exponential. In conclusion, morphometric data show the importance of the choice of the duration of treatment, the appropriate controls, and the age at which to begin the experiments.

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

    SciTech Connect

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

    1992-12-01

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

  13. Stress alleviates reduced expression of cell adhesion molecules (NCAM, L1), and deficits in learning and corticosterone regulation of apolipoprotein E knockout mice.

    PubMed

    Grootendorst, J; Oitzl, M S; Dalm, S; Enthoven, L; Schachner, M; de Kloet, E R; Sandi, C

    2001-11-01

    Cell adhesion molecules (CAMs) involved in synaptic changes underlying learning and memory processes, are implicated in the effect of stress on behavioural performance. The present study was designed to test the hypothesis that (i) expression of CAMs is apolipoprotein E- (apoE) genotype dependent and (ii) repeated exposure to stress modulates the synthesis of CAMs in an apoE-genotype dependent manner. Using ELISA we tested this hypothesis and measured expression of NCAM and L1 in different brain regions of naïve and stressed apolipoprotein E-knockout (apoE0/0) and C57Bl6 (wild-type) mice. Naïve apoE0/0 mice had elevated basal morning corticosterone and ACTH concentrations and decreased expression of NCAM and L1 compared to wild-type mice. Repeated exposure of mice to rats, as the common stressor, alleviated the reduction in expression of CAMs in apoE0/0 mice; seven days after the last rat exposure, expression of NCAM was increased in frontal brain and hippocampus whereas expression of L1 was increased in hippocampus and cerebellum. Rat stress attenuated the elevation of basal morning corticosterone concentration in apoE0/0 mice towards concentrations detected in wild-type mice. Moreover, rat stress improved learning and memory of apoE0/0 mice in the water maze. In conclusion, repeated exposure to stress eliminated apoE-genotype-related differences in expression of CAMs. Under these same conditions the differences in cognitive performance and corticosterone concentrations were abolished between wild type and apoE0/0 mice.

  14. UNC-45/CRO1/She4p (UCS) protein forms elongated dimer and joins two myosin heads near their actin binding region

    PubMed Central

    Shi, Hang; Blobel, Günter

    2010-01-01

    UNC-45/CRO1/She4p (UCS) proteins have variously been proposed to affect the folding, stability, and ATPase activity of myosins. They are the only proteins known to interact directly with the motor domain. To gain more insight into UCS function, we determined the atomic structure of the yeast UCS protein, She4p, at 2.9 Å resolution. We found that 16 helical repeats are organized into an L-shaped superhelix with an amphipathic N-terminal helix dangling off the short arm of the L-shaped molecule. In the crystal, She4p forms a 193-Å-long, zigzag-shaped dimer through three distinct and evolutionary conserved interfaces. We have identified She4p’s C-terminal region as a ligand for a 27-residue-long epitope on the myosin motor domain. Remarkably, this region consists of two adjacent, but distinct, binding epitopes localized at the nucleotide-responsive cleft between the nucleotide- and actin-filament-binding sites. One epitope is situated inside the cleft, the other outside the cleft. After ATP hydrolysis and Pi ejection, the cleft narrows at its base from 20 to 12 Å thereby occluding the inside the cleft epitope, while leaving the adjacent, outside the cleft binding epitope accessible to UCS binding. Hence, one cycle of higher and lower binding affinity would accompany one ATP hydrolysis cycle and a single step in the walk on an actin filament rope. We propose that a UCS dimer links two myosins at their motor domains and thereby functions as one of the determinants for step size of myosin on actin filaments. PMID:21115842

  15. High-affinity Manganese Coordination by Human Calprotectin is Calcium-dependent and Requires the Histidine-rich Site Formed at the Dimer Interface

    PubMed Central

    Hayden, Joshua A.; Brophy, Megan Brunjes; Cunden, Lisa S.; Nolan, Elizabeth M.

    2013-01-01

    Calprotectin (CP) is a transition metal-chelating antimicrobial protein of the calcium-binding S100 family that is produced and released by neutrophils. It inhibits the growth of various pathogenic microorganisms by sequestering the transition metal ions manganese and zinc. In this work, we investigate the manganese-binding properties of calprotectin. We demonstrate that the unusual His4 motif (site 2) formed at the S100A8/S100A9 dimer interface is the site of high-affinity Mn(II) coordination. We identify a low-temperature Mn(II) spectroscopic signal for this site consistent with an octahedral Mn(II) coordination sphere with simulated zero-field splitting parameters D = 270 MHz and E/D = 0.33 (E = 81 MHz). This analysis, combined with studies of mutant proteins, suggests that four histidine residues (H17 and H27 of S100A8; H91 and H95 of S100A9) coordinate Mn(II) in addition to two as-yet unidentified ligands. The His3Asp motif (site 1), which is also formed at the S100A8/S100A9 dimer interface, does not provide a high-affinity Mn(II) binding site. Calcium binding to the EF-hand domains of CP increases the Mn(II) affinity of the His4 site from the low-micromolar to the mid-nanomolar range. Metal-ion selectivity studies demonstrate that CP prefers to coordinate Zn(II) over Mn(II). Nevertheless, the specificity of Mn(II) for the His4 site provides CP with the propensity to form mixed Zn:Mn:CP complexes where one Zn(II) ion occupies site 1 and one Mn(II) ion occupies site 2. These studies support the notion that CP responds to physiological calcium ion gradients to become a high-affinity transition metal ion chelator in the extracellular space where it inhibits microbial growth. PMID:23276281

  16. Characterisation of the single copy trefoil peptides intestinal trefoil factor and pS2 and their ability to form covalent dimers.

    PubMed

    Chinery, R; Bates, P A; De, A; Freemont, P S

    1995-01-01

    A bacterial recombinant expression system was established to produce biologically active rat Intestinal Trefoil Factor (rITF). Characterisation of purified rITF shows that both monomers and dimers can be observed under reducing and non-reducing conditions, respectively. Site-directed mutagenesis studies show that Cys57 is necessary for rITF dimer formation. Samples of human gastrointestinal tissue following biopsy also demonstrated the presence of reducible human pS2 and ITF covalent dimers. Three-dimensional models for pS2 and ITF support the hypothesis that both pS2 and ITF can exist as disulphide-linked dimers in vivo and that any proposed function for these peptides must take dimer formation into account.

  17. Cloning of a cDNA encoding a putative human very low density lipoprotein/Apolipoprotein E receptor and assignment of the gene to chromosome 9pter-p23[sup 6

    SciTech Connect

    Gafvels, M.E.; Strauss, J.F. III ); Caird, M.; Patterson, D. ); Britt, D.; Jackson, C.L. )

    1993-11-01

    The authors report the cloning of a 3656-bp cDNA encoding a putative human very low density lipoprotein (VLDL)/apolipoprotein E (ApoE) receptor. The gene encoding this protein was mapped to chromosome 9pter-p23. Northern analysis of human RNA identified cognate mRNAs of 6.0 and 3.8 kb with most abundant expression in heart and skeletal muscle, followed by kidney, placenta, pancreas, and brain. The pattern of expression generally paralleled that of lipoprotein lipase mRNA but differed from that of the low density lipoprotein (LDL) receptor and the low density lipoprotein receptor-related protein/[alpha][sub 2]-macroglobulin receptor (LRP), which are members of the same gene family. VLDL/ApoE receptor message was not detected in liver, whereas mRNAs for both LDL receptor and LRP were found in hepatic tissue. In mouse 3T3-L1 cells, VLDL/ApoE receptor mRNA was induced during the transformation of the cells into adipocytes. Expression was also detected in human choriocarcinoma cells, suggesting that at least part of the expression observed in placenta may be in trophoblasts, cells which would be exposed to maternal blood. Expression in brain may be related to high levels of ApoE expression in that organ, an observation of potential relevance to the recently hypothesized role for ApoE in late onset Alzheimer disease. The results suggest that the putative VLDL/ApoE receptor could play a role in the uptake of triglyceride-rich lipoprotein particles by specific organs including striated and cardiac muscle and adipose tissue and in the transport of maternal lipids across the placenta. The findings presented here, together with recent observations from other laboratories, bring up the possibility that a single gene, the VLDL/ApoE receptor, may play a role in the pathogenesis of certain forms of atherosclerosis, Alzheimer disease, and obesity.

  18. Crystal Structure of a Novel Dimeric Form of NS5A Domain I Protein from Hepatitis C Virus

    SciTech Connect

    Love, Robert A.; Brodsky, Oleg; Hickey, Michael J.; Wells, Peter A.; Cronin, Ciarán N.; Pfizer

    2009-07-10

    A new protein expression vector design utilizing an N-terminal six-histidine tag and tobacco etch virus protease cleavage site upstream of the hepatitis C virus NS5A sequence has resulted in a more straightforward purification method and improved yields of purified NS5A domain I protein. High-resolution diffracting crystals of NS5A domain I (amino acids 33 to 202) [NS5A(33-202)] were obtained by using detergent additive crystallization screens, leading to the structure of a homodimer which is organized differently from that published previously (T. L. Tellinghuisen, J. Marcotrigiano, and C. M. Rice, Nature 435:374-379, 2005) yet is consistent with a membrane association model for NS5A. The monomer-monomer interface of NS5A(33-202) features an extensive buried surface area involving the most-highly conserved face of each monomer. The two alternate structural forms of domain I now available may be indicative of the multiple roles emerging for NS5A in viral RNA replication and viral particle assembly.

  19. RecA-binding pilE G4 sequence essential for pilin antigenic variation forms monomeric and 5' end-stacked dimeric parallel G-quadruplexes.

    PubMed

    Kuryavyi, Vitaly; Cahoon, Laty A; Seifert, H Steven; Patel, Dinshaw J

    2012-12-01

    Neisseria gonorrhoeae is an obligate human pathogen that can escape immune surveillance through antigenic variation of surface structures such as pili. A G-quadruplex-forming (G4) sequence (5'-G(3)TG(3)TTG(3)TG(3)) located upstream of the N. gonorrhoeae pilin expression locus (pilE) is necessary for initiation of pilin antigenic variation, a recombination-based, high-frequency, diversity-generation system. We have determined NMR-based structures of the all parallel-stranded monomeric and 5' end-stacked dimeric pilE G-quadruplexes in monovalent cation-containing solutions. We demonstrate that the three-layered all parallel-stranded monomeric pilE G-quadruplex containing single-residue double-chain reversal loops, which can be modeled without steric clashes into the 3 nt DNA-binding site of RecA, binds and promotes E. coli RecA-mediated strand exchange in vitro. We discuss how interactions between RecA and monomeric pilE G-quadruplex could facilitate the specialized recombination reactions leading to pilin diversification.

  20. Analysis of the Relationship between Estradiol and Follicle-Stimulating Hormone Concentrations and Polymorphisms of Apolipoprotein E and LeptinGenes in Women Post-Menopause

    PubMed Central

    Rył, Aleksandra; Jasiewicz, Andrzej; Grzywacz, Anna; Adler, Grażyna; Skonieczna-Żydecka, Karolina; Rotter, Iwona; Sipak-Szmigiel, Olimpia; Rumianowski, Bogdan; Karakiewicz, Beata; Jurczak, Anna; Parczewski, Miłosz; Urbańska, Anna; Grabowska, Marta; Laszczyńska, Maria

    2016-01-01

    Background: Menopause is the permanent cessation of menstruation due to loss of ovarian follicular activity. A review of the available literature indicates that correlations between the changes that take place in a woman’s body after menopause and different genetic variants are still being sought. Methods: The study was conducted in 252 women who had completed physiological menopause. The women were divided into groups according to the time elapsed since menopause. The total concentrations of estradiol and follicle-stimulating hormone were determined by means of electrochemiluminescence. The apolipoprotein E (APOE) and lepitn (LEP) genotypes were determined by real-time PCR and polymerase chain reaction–restriction fragment length polymorphism, respectively. Results: We observed that people with the APOE3/E3 genotype entered menopause insignificantly later compared to other genotypes. Additionally, in the group of patients with the APOE3/E3 genotypes, differences in the E2 concentration were significantly related to the time since their last menstruation. There is no association found in the literature between these polymorphisms of the LEP gene and hormones. Conclusions: To date, attempts to formulate a model describing the association between E2 and FSH concentration with the polymorphisms of various genes of menopause in women have not been successful. This relationship is difficult to study because of the number of nongenetic factors. Environmental factors can explain variation in postmenopausal changes in hormone levels. PMID:27240396

  1. A prospective study of cognitive health in the elderly (Oregon Brain Aging Study): effects of family history and apolipoprotein E genotype.

    PubMed Central

    Payami, H; Grimslid, H; Oken, B; Camicioli, R; Sexton, G; Dame, A; Howieson, D; Kaye, J

    1997-01-01

    The oldest old are the fastest-growing segment of our population and have the highest prevalence of dementia. Little is known about the genetics of cognitive health in the very old. The aim of this study was to determine whether the genetic risk factors for Alzheimer disease (AD)--namely, apolipoprotein E (APOE) epsilon4 allele and a family history of dementia-continue to be important factors in the cognitive health of the very old. Case-control studies suggest that the effect of genetic factors diminishes at age >75 years. The present prospective study provided evidence to the contrary. We studied 114 Caucasian subjects who were physically healthy and cognitively intact at age 75 years and who were followed, for an average of 4 years, with neurological, psychometric, and neuroimaging examinations. Excellent health at entry did not protect against cognitive decline. Incidence of cognitive decline rose sharply with age. epsilon4 and a family history of dementia (independent of epsilon4) were associated with an earlier age at onset of dementia. Subjects who had epsilon4 or a family history of dementia had a ninefold-higher age-specific risk for dementia than did those who had neither epsilon4 nor a family history of dementia. These observations suggest that the rate of cognitive decline increases with age and that APOE and other familial/genetic factors influence the onset age throughout life. PMID:9106542

  2. Gender difference in apolipoprotein E-associated risk for familial Alzheimer disease: a possible clue to the higher incidence of Alzheimer disease in women.

    PubMed Central

    Payami, H.; Zareparsi, S.; Montee, K. R.; Sexton, G. J.; Kaye, J. A.; Bird, T. D.; Yu, C. E.; Wijsman, E. M.; Heston, L. L.; Litt, M.; Schellenberg, G. D.

    1996-01-01

    Late-onset Alzheimer disease (AD) is associated with the apolipoprotein E (APOE)-epsilon4 allele. In late-onset familial AD, women have a significantly higher risk of developing the disease than do men. The aim of this study was to determine whether the gender difference in familial AD is a function of APOE genotype. We studied 58 late-onset familial AD kindreds. Kaplan-Meier survival analysis was used to assess genotype-specific distributions of age at onset. Odds ratios were estimated by logistic regression with adjustment for age and by conditional logistic regression with stratification on families. All methods detected a significant gender difference for the epsilon4 heterozygous genotype. In women, epsilon4 heterozygotes had higher risk than those without epsilon4; there was no significant difference between epsilon4 heterozygotes and epsilon4 homozygotes. In men, epsilon4 heterozygotes had lower risk than epsilon4 homozygotes; there was not significant difference between epsilon4 heterozygotes and those without epsilon4. A direct comparison of epsilon4 heterozygous men and women revealed a significant twofold increased risk in women. We confirmed these results in 15 autopsy-confirmed AD kindreds from the National Cell Repository at Indiana University Alzheimer Disease Center. These observations are consistent with the increased incidence of familial AD in women and may be a critical clue to the role of gender in the pathogenesis of AD. PMID:8644745

  3. Apolipoprotein E isoforms 3/3 and 3/4 differentially interact with circulating stearic, palmitic, and oleic fatty acids and lipid levels in Alaskan Natives.

    PubMed

    Castellanos-Tapia, Lyssia; López-Alvarenga, Juan Carlos; Ebbesson, Sven O E; Ebbesson, Lars O E; Tejero, M Elizabeth

    2015-04-01

    Lifestyle changes in Alaskan Natives have been related to the increase of cardiovascular disease and metabolic syndrome in the last decades. Variation of the apolipoprotein E (Apo E) genotype may contribute to the diverse response to diet in lipid metabolism and influence the association between fatty acids in plasma and risk factors for cardiovascular disease. The aim of this investigation was to analyze the interaction between Apo E isoforms and plasma fatty acids, influencing phenotypes related to metabolic diseases in Alaskan Natives. A sample of 427 adult Siberian Yupik Alaskan Natives was included. Fasting glucose, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, Apo A1, and Apo B plasma concentrations were measured using reference methods. Concentrations of 13 fatty acids in fasting plasma were analyzed by gas chromatography, and Apo E variants were identified. Analyses of covariance were conducted to identify Apo E isoform and fatty acid main effects and multiplicative interactions. The means for body mass index and age were 26 ± 5.2 and 47 ± 1.5, respectively. Significant main effects were observed for variation in Apo E and different fatty acids influencing Apo B levels, triglycerides, and total cholesterol. Significant interactions were found between Apo E isoform and selected fatty acids influencing total cholesterol, triglycerides, and Apo B concentrations. In summary, Apo E3/3 and 3/4 isoforms had significant interactions with circulating levels of stearic, palmitic, oleic fatty acids, and phenotypes of lipid metabolism in Alaskan Natives.

  4. Apolipoprotein E4 Prevents Growth of Malaria at the Intraerythrocyte Stage: Implications For Differences in Racial Susceptibility to Alzheimer’s Disease

    PubMed Central

    Fujioka, Hisashi; Phelix, Clyde F.; Friedland, Robert P.; Zhu, Xiongwei; Perry, Elizabeth A.; Castellani, Rudy J.; Perry, George

    2016-01-01

    Apolipoprotein E 4 (ApoE 4) has been linked to pathogenesis of Alzheimer’s disease and has been suggested to be maintained through evolutionary pressure via a protective role in malaria infection. We evaluated Plasmodium falciparum viability at the intraerythrocyte stage by exposure to plasma from human subjects with ApoE 4/4 or ApoE 3/3. Plasma samples from ApoE 4/4 but not ApoE 3/3 donors inhibited growth and disrupted morphology of P. falciparum. Evolutionary history is characterized by war between pathogenic microorganisms and defense mechanisms countering their pathogenicities. ApoE 4 frequency is highest in sub-Saharan Africa and other isolated populations (e.g., Papua New Guinea) that exhibit endemic malaria. High ApoE frequency may offer selective advantage protecting against some infectious diseases (e.g., Plasmodium falciparum). These results implicate evolutionary pressure by malaria selecting humans with ApoE 4/4, even considering lower survival in late life. These selective advantages may be relevant in the exploration of possible disparities between Black and Whites in the incidence of Alzheimer’s Disease. PMID:24241262

  5. Posterior cingulate γ-aminobutyric acid and glutamate/glutamine are reduced in amnestic mild cognitive impairment and are unrelated to amyloid deposition and apolipoprotein E genotype.

    PubMed

    Riese, Florian; Gietl, Anton; Zölch, Niklaus; Henning, Anke; O'Gorman, Ruth; Kälin, Andrea M; Leh, Sandra E; Buck, Alfred; Warnock, Geoffrey; Edden, Richard A E; Luechinger, Roger; Hock, Christoph; Kollias, Spyros; Michels, Lars

    2015-01-01

    The biomarker potential of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) for the in vivo characterization of preclinical stages in Alzheimer's disease has not yet been explored. We measured GABA, glutamate + glutamine (Glx), and N-acetyl-aspartate (NAA) levels by single-voxel MEGA-PRESS magnetic resonance spectroscopy in the posterior cingulate cortex of 21 elderly subjects and 15 patients with amnestic mild cognitive impairment. Participants underwent Pittsburgh Compound B positron emission tomography, apolipoprotein E (APOE) genotyping, and neuropsychological examination. GABA, Glx, and NAA levels were significantly lower in patients. NAA was lower in Pittsburgh Compound B-positive subjects and APOE ε4 allele carriers. GABA, Glx, and NAA levels were positively correlated to CERAD word learning scores. Reductions in GABA, Glx, and NAA levels may serve as metabolic biomarkers for cognitive impairment in amnestic mild cognitive impairment. Because GABA and Glx do not seem to reflect amyloid β deposition or APOE genotype, they are less likely biomarker candidates for preclinical Alzheimer's disease.

  6. The modulation of endoplasmic reticulum stress by chemical chaperone upregulates immune negative cytokine IL-35 in apolipoprotein E-deficient mice.

    PubMed

    Wang, Bo; Dai, Shen; Dong, Zhaojing; Sun, Yue; Song, Xingguo; Guo, Chun; Zhu, Faliang; Wang, Qun; Zhang, Lining

    2014-01-01

    Interleukin (IL)-35 is a newly identified immune negative molecule which is secreted by CD4(+)Foxp3(+) T regulatory cells (Tregs) and contributes to their suppressive capacity. Early data have shown that IL-35 inhibits development of several autoimmune diseases. However, the role of IL-35 in atherosclerosis, a lipid-driven chronic inflammatory disease in arterial wall, remains to be investigated. Here, we found that IL-35 was involved in atherosclerosis in apolipoprotein E-deficient (ApoE(-/-)) mice. ApoE(-/-) mice with established atherosclerotic lesion displayed a lower level of IL-35 compared to age-matched wild type C57BL/6 mice without plaque. However, IL-35 expression increased significantly in ApoE(-/-) mice with attenuated plaque. More importantly, we found that modulation of ER stress treated by chemical chaperone, 4-Phenyl butyric acid (PBA) in vivo, mainly upregulated immune negative regulating molecule IL-35, as well as IL-10 and Foxp3, accompanied by increased Tregs. However, no obvious impact on pro-inflammatory molecules such as TNF-α, IFN-γ, IL-17 and IL-23 was observed, which provides new insight into the benefit of ER stress recovery from attenuated plaque. Our results suggest that IL-35 might have a potential value for atherosclerotic therapy.

  7. Deficiency of cyclin-dependent kinase inhibitors p21{sup Cip1} and p27{sup Kip1} accelerates atherogenesis in apolipoprotein E-deficient mice

    SciTech Connect

    Akyuerek, Levent M.; Boehm, Manfred; Olive, Michelle; Zhou, Alex-Xianghua; San, Hong; Nabel, Elizabeth G.

    2010-05-28

    Cyclin-dependent kinase inhibitors, p21{sup Cip1} and p27{sup Kip1}, are upregulated during vascular cell proliferation and negatively regulate growth of vascular cells. We hypothesized that absence of either p21{sup Cip1} or p27{sup Kip1} in apolipoprotein E (apoE)-deficiency may increase atherosclerotic plaque formation. Compared to apoE{sup -/-} aortae, both apoE{sup -/-}/p21{sup -/-} and apoE{sup -/-}/p27{sup -/-} aortae exhibited significantly more atherosclerotic plaque following a high-cholesterol regimen. This increase was particularly observed in the abdominal aortic regions. Deficiency of p27{sup Kip1} accelerated plaque formation significantly more than p21{sup -/-} in apoE{sup -/-} mice. This increased plaque formation was in parallel with increased intima/media area ratios. Deficiency of p21{sup Cip1} and p27{sup Kip1} accelerates atherogenesis in apoE{sup -/-} mice. These findings have significant implications for our understanding of the molecular basis of atherosclerosis associated with excessive proliferation of vascular cells.

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

    PubMed Central

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

    2015-01-01

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

  9. Deletion of apolipoprotein E receptor-2 in mice lowers brain selenium and causes severe neurological dysfunction and death when a low-selenium diet is fed.

    PubMed

    Burk, Raymond F; Hill, Kristina E; Olson, Gary E; Weeber, Edwin J; Motley, Amy K; Winfrey, Virginia P; Austin, Lori M

    2007-06-01

    Selenoprotein P (Sepp1) is a plasma and extracellular protein that is rich in selenium. Deletion of Sepp1 results in sharp decreases of selenium levels in the brain and testis with dysfunction of those organs. Deletion of Sepp1 also causes increased urinary selenium excretion, leading to moderate depletion of whole-body selenium. The lipoprotein receptor apolipoprotein E receptor-2 (apoER2) binds Sepp1 and facilitates its uptake by Sertoli cells, thus providing selenium for spermatogenesis. Experiments were performed to assess the effect of apoER2 on the concentration and function of selenium in the brain and on whole-body selenium. ApoER2-/- and apoER2+/+ male mice were fed a semipurified diet with selenite added as the source of selenium. ApoER2-/- mice had depressed brain and testis selenium, but normal levels in liver, kidney, muscle, and the whole body. Feeding a selenium-deficient diet to apoER2-/- mice led to neurological dysfunction and death, with some of the characteristics exhibited by Sepp1-/- mice fed the same diet. Thus, although it does not affect whole-body selenium, apoER2 is necessary for maintenance of brain selenium and for prevention of neurological dysfunction and death under conditions of selenium deficiency, suggesting an interaction of apoER2 with Sepp1 in the brain.

  10. Fatty acid metabolism in carriers of apolipoprotein E epsilon 4 allele: is it contributing to higher risk of cognitive decline and coronary heart disease?

    PubMed

    Chouinard-Watkins, Raphaël; Plourde, Mélanie

    2014-10-01

    Apolipoprotein E (ApoE) is a protein playing a pivotal role in lipid homeostasis since it regulates cholesterol, triglyceride and phospholipid metabolism in the blood and the brain. APOE gene regulates the expression of this protein and has three different alleles: ε2, ε3 and ε4. Carrying an APOE4 allele is recognised as a genetic risk factor of late-onset Alzheimer's disease (LOAD) and coronary heart disease (CHD). Consuming fatty fish, rich in long chain omega-3 fatty acids (LC omega-3), seems to be associated with risk reduction of developing LOAD and CHD but this link seems not to hold in APOE4 carriers, at least in LOAD. In CHD trials, APOE4 carriers supplemented with LC omega-3 were categorized as differential responders to the treatment with regards to CHD risk markers. This is potentially because fatty acid metabolism is disturbed in APOE4 carriers compared to the non-carriers. More specifically, homeostasis of LC omega-3 is disrupted in carriers of APOE4 allele and this is potentially because they β-oxidize more LC omega-3 than the non-carriers. Therefore, there is a potential shift in fatty acid selection for β-oxidation towards LC omega-3 which are usually highly preserved for incorporation into cell membranes. PMID:25333200

  11. Hyperglycemia Induced by Glucokinase Deficiency Accelerates Atherosclerosis Development and Impairs Lesion Regression in Combined Heterozygous Glucokinase and the Apolipoprotein E-Knockout Mice

    PubMed Central

    Adingupu, Damilola D.; Andréasson, Anne-Christine; Ahnmark, Andrea

    2016-01-01

    Aim. Models combining diabetes and atherosclerosis are important in evaluating the cardiovascular (CV) effects and safety of antidiabetes drugs in the development of treatments targeting CV complications. Our aim was to evaluate if crossing the heterozygous glucokinase knockout mouse (GK+/−) and hyperlipidemic mouse deficient in apolipoprotein E (ApoE−/−) will generate a disease model exhibiting a diabetic and macrovascular phenotype. Methods. The effects of defective glucokinase on the glucose metabolism and on the progression and regression of atherosclerosis on high-fat diets were studied in both genders of GK+/−ApoE−/− and ApoE−/− mice. Coronary vascular function of the female GK+/−ApoE−/− and ApoE−/− mice was also investigated. Results. GK+/−ApoE−/− mice show a stable hyperglycemia which was increased on Western diet. In oral glucose tolerance test, GK+/−ApoE−/− mice showed significant glucose intolerance and impaired glucose-stimulated insulin secretion. Plasma lipids were comparable with ApoE−/− mice; nevertheless the GK+/−ApoE−/− mice showed slightly increased atherosclerosis development. Conclusions. The GK+/−ApoE−/− mice showed a stable and reproducible hyperglycemia, accelerated atherosclerotic lesion progression, and no lesion regression after lipid lowering. This novel model provides a promising tool for drug discovery, enabling the evaluation of compound effects against both diabetic and cardiovascular endpoints simultaneously in one animal model. PMID:27774459

  12. Gender difference in apolipoprotein E-associated risk for familial Alzheimer disease: A possible clue to the higher incidence of Alzheimer disease in women

    SciTech Connect

    Payami, H.; Zareparsi, S.; Montee, K.R.; Litt, M.

    1996-04-01

    Late-onset Alzheimer disease (AD) is associated with the apolipoprotein E (APOE)-{epsilon}4 allele. In late-onset familial AD, women have a significantly higher risk of developing the disease than do men. The aim of this study was to determine whether the gender difference in familial AD is a function of APOE genotype. We studied 58 late-onset familial AD kindreds. Kaplan-Meier survival analysis was used to assess genotype-specific distributions of age at onset. Odds ratios were estimated by logistic regression with adjustment for age and by conditional logistic regression with stratification on families. All methods detected a significant gender difference for the {epsilon}4 heterozygous genotype. In women, {epsilon}4 heterozygotes had higher risk than those without {epsilon}4; there was no significant difference between {epsilon}4 heterozygotes and {epsilon}4 homozygotes. In men, {epsilon}4 heterozygotes had lower risk than {epsilon}4 homozygotes; there was no significant difference between {epsilon}4 heterozygotes and those without {epsilon}4. A direct comparison of {epsilon}4 heterozygous men and women revealed a significant two-fold increased risk in women. We confirmed these results in 15 autopsy-confirmed AD kindreds from the National Cell Repository at Indiana University Alzheimer Disease Center. These observations are consistent with the increased incidence of familial AD in women and may be a critical clue to the role of gender in the pathogenesis of AD. 53 refs., 2 figs., 2 tabs.

  13. Genetic linkage of hyperglycemia, body weight and serum amyloid-P in an intercross between C57BL/6 and C3H apolipoprotein E-deficient mice.

    PubMed

    Su, Zhiguang; Li, Yuhua; James, Jessica C; Matsumoto, Alan H; Helm, Gregory A; Lusis, Aldons J; Shi, Weibin

    2006-05-15

    Dyslipidemia and hyperglycemia are integral components of the metabolic perturbations in type 2 diabetes. Apolipoprotein E-deficient (apoE(-/-)) mice develop severe hyperlipidemia and significant hyperglycemia when fed a western diet containing 21% fat (w/w), 0.15% cholesterol and 19.5% casein. Using an intercross between C57BL/6J (B6) and C3H/HeJ (C3H) apoE(-/-) mice, we performed quantitative trait locus (QTL) analysis to identify loci contributing to hyperglycemia and associated traits. Fasting plasma levels of glucose, insulin and serum amyloid-P (SAP) and body weight in 234 female F2 mice were measured after being fed the western diet for 12 weeks. QTL analysis revealed one significant QTL, named Bglu3 [95.8 cM, logarithm of odds ratio (OR)(LOD) 4.1], on chromosome 1 and a suggestive QTL on chromosome 9 (38 cM, LOD 2.3) that influenced plasma glucose levels. Bglu3 coincided with loci on distal chromosomal 1 that had a major influence on plasma SAP levels and body weight. Significant correlations between plasma glucose, SAP and body weight were observed in F2 mice. Thus, these results demonstrate genetic linkages of hyperglycemia and body weight with SAP, a marker of the acute-phase response, in hyperlipidemic apoE(-/-) mice and suggest a probability for the Sap gene to be a positional candidate of Bglu3.

  14. Genes determining the severity of cerebral palsy: the role of single nucleotide polymorphisms on the amount and structure of apolipoprotein E

    PubMed Central

    Lien, Espen; Andersen, Guro; Bao, Yongde; Gordish-Dressman, Heather; Skranes, Jon S.; Blackman, James A.; Vik, Torstein

    2015-01-01

    Aim ApolipoproteinE (apoE) influences repair and other processes in the brain and the apoE4 variant is a risk factor for Alzheimer's disease and for prolonged recovery following traumatic brain injury. We previously reported that specific single nucleotide polymorphisms in the APOE or TOMM40 genes affecting the structure and production of apoE were associated with epilepsy, more impaired hand function and gastrostomy tube feeding in children with cerebral palsy (CP). This study explored how various combinations of the same polymorphisms may affect these clinical manifestations. Methods Successful DNA analyses of APOE and TOMM40 were carried out on 227 children. The CP Register of Norway provided details of gross and fine motor function, epilepsy and gastrostomy tube feeding. Possible associations between these clinical manifestations and various combinations of the APOEε2, ε3 or ε4 alleles and of the rs59007384 polymorphism in the TOMM40 gene were explored. Results Epilepsy, impaired fine motor function and gastrostomy tube feeding were less common in children carrying the combination of rs59007384 GG and APOEε2 or ε3 than in children with other combinations. Conclusion Our findings suggest that specific combinations of genes influence the structure and production of apoE differently and affect the clinical manifestations of CP. PMID:25703783

  15. Interleukin-8-251T > A, Interleukin-1α-889C > T and Apolipoprotein E polymorphisms in Alzheimer’s disease

    PubMed Central

    Vendramini, Alex Augusto; de Lábio, Roger Willian; Rasmussen, Lucas Trevizani; dos Reis, Nathali Mattiuzo; Minett, Thais; Bertolucci, Paulo Henrique Ferreira; de Souza Pinhel, Marcela Augusta; Souza, Dorotéia Rossi Silva; Mazzotti, Diego Robles; de Arruda Cardoso Smith, Marília; Payão, Spencer Luiz Marques

    2011-01-01

    An inflammatory process has been involved in numerous neurodegenerative disorders such as Parkinson’s disease, stroke and Alzheimer’s disease (AD). In AD, the inflammatory response is mainly located in the vicinity of amyloid plaques. Cytokines, such as interleukin-8 (IL-8) and interleukin-1α (IL-1α), have been clearly involved in this inflammatory process. Polymorphisms of several interleukin genes have been correlated to the risk of developing AD. The present study investigated the association of AD with polymorphisms IL-8 -251T > A (rs4073) and IL-1α-889C > T (rs1800587) and the interactive effect of both, adjusted by the Apolipoprotein E genotype. 199 blood samples from patients with AD, 146 healthy elderly controls and 95 healthy young controls were obtained. DNA samples were isolated from blood cells, and the PCR-RFLP method was used for genotyping. The genotype distributions of polymorphisms IL-8, IL-1α and APOE were as expected under Hardy-Weinberg equilibrium. The allele frequencies did not differ significantly among the three groups tested. As expected, the APOE4 allele was strongly associated with AD (p < 0.001). No association of AD with either the IL-1α or the IL-8 polymorphism was observed, nor was any interactive effect between both polymorphisms. These results confirm previous studies in other populations, in which polymorphisms IL-8 -251T > A and IL-1α-889C > T were not found to be risk factors for AD. PMID:21637534

  16. Recoupling of eNOS with Folic Acid Prevents Abdominal Aortic Aneurysm Formation in Angiotensin II-Infused Apolipoprotein E Null Mice

    PubMed Central

    Siu, Kin Lung; Miao, Xiao Niu; Cai, Hua

    2014-01-01

    We have previously shown that eNOS uncoupling mediates abdominal aortic aneurysm (AAA) formation in hph-1 mice. In the present study we examined whether recoupling of eNOS prevents AAA formation in a well-established model of Angiotensin II-infused apolipoprotein E (apoE) null mice by targeting some common pathologies of AAA. Infusion of Ang II resulted in a 92% incidence rate of AAA in the apoE null animals. In a separate group, animals were treated orally with folic acid (FA), which is known to recouple eNOS through augmentation of dihydrofolate reductase (DHFR) function. This resulted in a reduction of AAA rate to 19.5%. Imaging with ultrasound showed that FA markedly inhibited expansion of abdominal aorta. FA also abolished elastin breakdown and macrophage infiltration in the AAA animals. The eNOS uncoupling activity, assessed by L-NAME-sensitive superoxide production, was minimal at baseline but greatly exaggerated with Ang II infusion, which was completely attenuated by FA. This was accompanied by markedly improved tetrahydrobiopterin and nitric oxide bioavailability. Furthermore, the expression and activity of DHFR was decreased in Ang II-infused apoE null mice specifically in the endothelial cells, while FA administration resulted in its recovery. Taken together, these data further establish a significant role of uncoupled eNOS in mediating AAA formation, and a universal efficacy of FA in preventing AAA formation via restoration of DHFR to restore eNOS function. PMID:24558445

  17. High-throughput method for determination of apolipoprotein E genotypes with use of restriction digestion analysis by microplate array diagonal gel electrophoresis.

    PubMed

    Bolla, M K; Haddad, L; Humphries, S E; Winder, A F; Day, I N

    1995-11-01

    Molecular epidemiological research has identified the association of a common apolipoprotein E (apo E) isoform (E4 as opposed to E3), with risk both of coronary artery disease and of Alzheimer dementia. In addition, the role of apo E genotype (usually E2/E2) in Type III hyperlipidemia is well known. However, both for diagnostic and research purposes, apo E genotyping is cumbersome. The preferred approach is electrophoretic sizing of restriction digestion fragments, enabling simultaneous analysis of the two codons (112 and 158) that represent the six common genotypes (E2/E2; E2/E3; E2/E4; E3/E3; E3/E4; E4/E4). However, the consequent demands of high-yield PCR, high-resolution, high-throughput electrophoresis, and sufficient detection sensitivity have left shortfalls in published protocols. In conjunction with a high-throughput electrophoresis system we described recently, microplate array diagonal gel electrophoresis (MADGE), we have constructed extensively optimized, simplified protocols for DNA isolation from mouthwash samples for PCR setup and high-yield PCR, for restriction digestion, and for subsequent MADGE gel image analysis. The integral system enables one worker to readily undertake apo E genotyping of as many as hundreds of DNA samples per day, without special equipment.

  18. Fucoidan alleviates high-fat diet-induced dyslipidemia and atherosclerosis in ApoE(shl) mice deficient in apolipoprotein E expression.

    PubMed

    Yokota, Takashi; Nomura, Koichi; Nagashima, Mikio; Kamimura, Naomi

    2016-06-01

    Fucoidan, a sulfated polysaccharide extracted from brown seaweeds, possesses many biological activities including anti-inflammatory and antioxidant activities. We aimed to investigate the protective effects of fucoidan on dyslipidemia and atherosclerosis in apolipoprotein E-deficient mice (ApoE(shl) mice) and to elucidate its molecular targets in the liver by using a transcriptomic approach. For 12weeks, ApoE(shl) mice were fed a high-fat diet (HFD) supplemented with either 1% or 5% fucoidan. Fucoidan supplementation significantly reduced tissue weight (liver and white adipose tissue), blood lipid, total cholesterol (TC), triglyceride (TG), non-high-density lipoprotein cholesterol (non-HDL-C) and glucose levels in HFD-fed ApoE(shl) mice but increased plasma lipoprotein lipase (LPL) activity and HDL-C levels. Fucoidan also reduced hepatic steatosis levels (liver size, TC and TG levels, and lipid peroxidation) and increased white adipose tissue LPL activity. DNA microarray analysis and quantitative reverse transcription-polymerase chain reaction demonstrated differential expression of genes encoding proteins involved in lipid metabolism, energy homeostasis and insulin sensitivity, by activating Ppara and inactivating Srebf1. Fucoidan supplementation markedly reduced the thickness of the lipid-rich plaque, lipid peroxidation and foaming macrophage accumulation in the aorta in HFD-fed ApoE(shl) mice. Thus, fucoidan supplementation appears to have anti-dyslipidemic and anti-atherosclerotic effects by inducing LPL activity and inhibiting the effects of inflammation and oxidative stress in HFD-fed ApoE(shl) mice.

  19. High-Fat Diet Changes Hippocampal Apolipoprotein E (ApoE) in a Genotype- and Carbohydrate-Dependent Manner in Mice.

    PubMed

    Lane-Donovan, Courtney; Herz, Joachim

    2016-01-01

    Alzheimer's disease is a currently incurable neurodegenerative disease affecting millions of individuals worldwide. Risk factors for Alzheimer's disease include genetic risk factors, such as possession of ε4 allele of apolipoprotein E (ApoE4) over the risk-neutral ApoE3 allele, and lifestyle risk factors, such as diet and exercise. The intersection of these two sources of disease risk is not well understood. We investigated the impact of diet on ApoE levels by feeding wildtype, ApoE3, and ApoE4 targeted replacement (TR) mice with chow, high-fat, or ketogenic (high-fat, very-low-carbohydrate) diets. We found that high-fat diet affected both plasma and hippocampal levels of ApoE in an isoform-dependent manner, with high-fat diet causing a surprising reduction of hippocampal ApoE levels in ApoE3 TR mice. Conversely, the ketogenic diet had no effect on hippocampal ApoE. Our findings suggest that the use of dietary interventions to slow the progression AD should take ApoE genotype into consideration.

  20. Substantial effects of apolipoprotein E ε4 on memory decline in very old age: longitudinal findings from a population-based sample.

    PubMed

    Praetorius, Marcus; Thorvaldsson, Valgeir; Hassing, Linda B; Johansson, Boo

    2013-12-01

    We examined associations between the apolipoprotein E (APOE) ε4 allele and levels of performance and rates of change in cognition in late life taking incident dementia into account. The sample consisted of 482 nondemented individuals, aged 80 years and older at baseline, drawn from the OCTO twin study. A battery of 10 cognitive tests was administered at 5 occasions with measurements intervals of 2 years. We fitted hierarchical linear models with time specified as time to death and controlled for baseline age, sex, education, stroke, cardiovascular disease, hypertension, diabetes, and incident dementia. The ε4 allele was significantly associated with lower levels of performance or steeper rate of decline in all 7 memory tests. Largest effect sizes were found in tests of delayed recall and recognition memory. The effects of the APOE ε4 allele were, however, reduced to a nonsignificant level in all tests except 1 after accounting for incident dementia. The findings support the notion that the APOE ε4 allele is associated with substantial memory decline in very old age, but as expected, the effect is largely related to incident dementia.

  1. Investigation of long chain omega-3 PUFAs on arterial blood pressure, vascular reactivity and survival in angiotensin II-infused Apolipoprotein E-knockout mice.

    PubMed

    Bürgin-Maunder, Corinna S; Nataatmadja, Maria; Vella, Rebecca K; Fenning, Andrew S; Brooks, Peter R; Russell, Fraser D

    2016-02-01

    Abdominal aortic aneurysm (AAA) is an inflammatory vascular disease. Long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs) decrease inflammation and oxidative stress in an angiotensin II-infused apolipoprotein E-knockout (ApoE(-/-)) mouse model of AAA. This study investigated the effects of LC n-3 PUFAs on blood pressure and vascular reactivity in fourteen angiotensin II-infused ApoE(-/-) male mice. Blood pressure was obtained using a non-invasive tail cuff method and whole blood was collected by cardiac puncture. Vascular reactivity of the thoracic aorta was assessed using wire myography and activation of endothelial nitric oxide synthase (eNOS) was determined by immunohistochemistry. A high LC n-3 PUFA diet increased the omega-3 index and reduced the n-6 to n-3 PUFA ratio. At day 10 post-infusion with angiotensin II, there was no difference in systolic blood pressure or diastolic blood pressure in mice fed the high or low n-3 PUFA diets. The high LC n-3 PUFA diet resulted in a non-significant trend for delay in time to death from abdominal aortic rupture. Vascular reactivity and eNOS activation remained unchanged in mice fed the high compared to the low LC n-3 PUFA diet. This study argues against direct improvement in vascular reactivity in ApoE(-/-) mice that were supplemented with n-3 PUFA for 8 weeks prior to infusion with angiotensin II.

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

    PubMed Central

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

    1991-01-01

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

  3. Roles of apolipoprotein E4 (ApoE4) in the pathogenesis of Alzheimer's disease: lessons from ApoE mouse models.

    PubMed

    Huang, Yadong

    2011-08-01

    ApoE4 (apolipoprotein E4) is the major known genetic risk factor for AD (Alzheimer's disease). In most clinical studies, apoE4 carriers account for 65-80% of all AD cases, highlighting the importance of apoE4 in AD pathogenesis. Emerging data suggest that apoE4, with its multiple cellular origins and multiple structural and biophysical properties, contributes to AD in multiple ways either independently or in combination with other factors, such as Aβ (amyloid β-peptide) and tau. Many apoE mouse models have been established to study the mechanisms underlying the pathogenic actions of apoE4. These include transgenic mice expressing different apoE isoforms in neurons or astrocytes, those expressing neurotoxic apoE4 fragments in neurons and human apoE isoform knock-in mice. Since apoE is expressed in different types of cells, including astrocytes and neurons, and in brains under diverse physiological and/or pathophysiological conditions, these apoE mouse models provide unique tools to study the cellular source-dependent roles of apoE isoforms in neurobiology and in the pathogenesis of AD. They also provide useful tools for discovery and development of drugs targeting apoE4's detrimental effects.

  4. Genetic influence of apolipoprotein E4 genotype on hippocampal morphometry: An N = 725 surface-based Alzheimer's disease neuroimaging initiative study.

    PubMed

    Shi, Jie; Leporé, Natasha; Gutman, Boris A; Thompson, Paul M; Baxter, Leslie C; Caselli, Richard J; Wang, Yalin

    2014-08-01

    The apolipoprotein E (APOE) e4 allele is the most prevalent genetic risk factor for Alzheimer's disease (AD). Hippocampal volumes are generally smaller in AD patients carrying the e4 allele compared to e4 noncarriers. Here we examined the effect of APOE e4 on hippocampal morphometry in a large imaging database-the Alzheimer's Disease Neuroimaging Initiative (ADNI). We automatically segmented and constructed hippocampal surfaces from the baseline MR images of 725 subjects with known APOE genotype information including 167 with AD, 354 with mild cognitive impairment (MCI), and 204 normal controls. High-order correspondences between hippocampal surfaces were enforced across subjects with a novel inverse consistent surface fluid registration method. Multivariate statistics consisting of multivariate tensor-based morphometry (mTBM) and radial distance were computed for surface deformation analysis. Using Hotelling's T(2) test, we found significant morphological deformation in APOE e4 carriers relative to noncarriers in the entire cohort as well as in the nondemented (pooled MCI and control) subjects, affecting the left hippocampus more than the right, and this effect was more pronounced in e4 homozygotes than heterozygotes. Our findings are consistent with previous studies that showed e4 carriers exhibit accelerated hippocampal atrophy; we extend these findings to a novel measure of hippocampal morphometry. Hippocampal morphometry has significant potential as an imaging biomarker of early stage AD.

  5. Interactive effects of apolipoprotein E4 and diabetes risk on later myelinating white matter regions in neurologically healthy older aged adults.

    PubMed

    Foley, Jessica M; Salat, David H; Stricker, Nikki H; Zink, Tyler A; Grande, Laura J; McGlinchey, Regina E; Milberg, William P; Leritz, Elizabeth C

    2014-05-01

    Possession of the apolipoprotein E4 (APOE4) allele and diabetes risk are independently related to reduced white matter (WM) integrity that may contribute to the development of Alzheimer's disease (AD). The purpose of this study is to examine the interactive effects of APOE4 and diabetes risk on later myelinating WM regions among healthy elderly individuals at risk of AD. A sample of 107 healthy elderly (80 APOE4-/27 APOE4+) individuals underwent structural magnetic resonance imaging/diffusion tensor imaging (DTI). Data were prepared using Tract-Based Spatial Statistics, and a priori regions of interest (ROIs) were extracted from T1-based WM parcellations. Regions of interest included later myelinating frontal/temporal/parietal WM regions and control regions measured by fractional anisotropy (FA). There were no APOE group differences in DTI for any ROI. Within the APOE4 group, we found negative relationships between hemoglobin A1c/fasting glucose and APOE4 on FA for all later myelinating WM regions but not for early/middle myelinating control regions. Results also showed APOE4/diabetes risk interactions for WM underlying supramarginal, superior temporal, precuneus, superior parietal, and superior frontal regions. Results suggest interactive effects of APOE4 and diabetes risk on later myelinating WM regions, which supports preclinical detection of AD among this particularly susceptible subgroup.

  6. Synergistic epistasis of paraoxonase 1 (rs662 and rs85460) and apolipoprotein E4 genes in pathogenesis of Alzheimer's disease and vascular dementia.

    PubMed

    Alam, Rizwan; Tripathi, Manjari; Mansoori, Nasim; Parveen, Shama; Luthra, Kalpana; Lakshmy, Ramakrishnan; Sharma, Subhadra; Arulselvi, Subramanian; Mukhopadhyay, Asok K

    2014-12-01

    Genetic polymorphism and epistasis play a role in etiopathogenesis of Alzheimer's disease (AD) and vascular dementia (VaD). In this case-control study, a total of 241 patients were included in the study to see the effect of paraoxonase 1 (PON1; rs662 and rs85460) and apolipoprotein E (ApoE) genes in altering the odds of having AD and VaD along with serum PON and lipid profile. The presence of at least 1 variant allele of rs662, but not rs85460, increased the risk of having AD by 1.8-fold (95% confidence interval [CI]: 0.97-3.40) and VaD by 3.09-fold (95% CI: 1.4-6.9). The interaction between PON1 genes (rs662 and rs85460) and ApoE genes showed synergistic epistasis in altering the odds of significantly having both AD and VaD. On the other hand, low serum level of high-density lipoprotein and low level of serum PON activity were found associated significantly (P ≤ .001 in both cases) only in patients with VaD as compared to healthy control.

  7. The association between small vessel infarcts and the activities of amyloid-β peptide degrading proteases in apolipoprotein E4 allele carriers.

    PubMed

    Zhu, Haihao; Bhadelia, Rafeeque A; Liu, Zhiheng; Vu, Linh; Li, Huajie; Scott, Tammy; Bergethon, Peter; Mwamburi, Mkaya; Rosenzweig, James L; Rosenberg, Irwine; Qiu, Wei Qiao

    2013-11-01

    Small vessel (SV) and large vessel (LV) brain infarcts are distinct pathologies. Using a homebound elderly sample, the numbers of either infarct subtypes were similar between those apolipoprotein E4 allele (ApoE4) carriers (n = 80) and noncarriers (n = 243). We found that the higher the number of SV infarcts, but not LV infarcts, a participant had, the higher the activity of substrate V degradation in serum especially among ApoE4 carriers (β = +0.154, SE = 0.031, P < .0001) after adjusting for the confounders. Since substrate V degradation could be mediated by insulin-degrading enzyme (IDE) or/and angiotensin-converting enzyme (ACE), but no relationship was found between SV infarcts and specific ACE activities, blood IDE may be a useful biomarker to distinguish the brain infarct subtypes. Insulin-degrading enzyme in blood may also imply an important biomarker and a pathological event in Alzheimer disease through SV infarcts in the presence of ApoE4.

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

    PubMed

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

    2015-09-08

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

  9. Apolipoprotein e4 affects topographical changes in hippocampal and cortical atrophy in Alzheimer's disease dementia: a five-year longitudinal study.

    PubMed

    Kim, Yeo Jin; Cho, Hanna; Kim, Yun Joong; Ki, Chang-Seok; Chung, Sun Ju; Ye, Byoung Seok; Kim, Hee Jin; Kim, Jung-Hyun; Kim, Sung Tae; Lee, Kyung Han; Jeon, Seun; Lee, Jong-Min; Chin, Juhee; Kim, Jeong-Hun; Na, Duk L; Seong, Joon-Kyung; Seo, Sang Won

    2015-01-01

    Apolipoprotein E4 (APOE4) is a genetic risk factor for developing Alzheimer's disease (AD). Once AD manifests clinically, however, the effects of APOE4 are less clear. Therefore, we investigated the longitudinal effects of APOE4 on topographical changes in AD patient brain atrophy. We prospectively recruited 35 patients with AD (19 APOE4 carriers and 16 non-carriers), and 14 normal controls, then followed them for five years. We measured hippocampal deformities and cortical thickness. Hippocampal comparison between APOE4 carriers and non-carriers with AD showed carriers had rapid changes in the head and body, while non-carriers had rapid changes in a small portion of the body. Cortical thickness comparison between APOE4 carriers and non-carriers with AD dementia showed carriers had rapid thinning in the lateral frontal, temporal, and parietal regions, while no region showed more rapid cortical thinning in non-carriers than in carriers. These findings underlined the importance of the APOE4 allele for designing and interpreting future treatment trials in patients with AD dementia.

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

    PubMed

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

    2007-07-17

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

  11. Structural basis for enhanced neutralization of HIV-1 by a dimeric IgG form of the glycan-recognizing antibody 2G12

    PubMed Central

    Wu, Yunji; West, Anthony P.; Kim, Helen J.; Thornton, Matthew E.; Ward, Andrew B.; Bjorkman, Pamela J.

    2013-01-01

    SUMMARY The human IgG 2G12 recognizes high-mannose carbohydrates on the HIV-1 envelope glycoprotein gp120. Its two antigen-binding fragments (Fabs) are intramolecularly domain exchanged, resulting in a rigid (Fab)2 unit including a third antigen-binding interface not found in antibodies with flexible Fab arms. We determined crystal structures of dimeric 2G12 IgG created by intermolecular domain exchange, which exhibits increased breadth and >50-fold increased neutralization potency compared with monomeric 2G12. The four Fab and two Fc regions of dimeric 2G12 were localized at low resolution in two independent structures, revealing IgG dimers with two (Fab)2 arms analogous to the Fabs of conventional monomeric IgGs. Structures revealed three conformationally-distinct dimers, demonstrating flexibility of the (Fab)2–Fc connections that was confirmed by electron microscopy, small-angle X-ray scattering, and binding studies. We conclude that intermolecular domain exchange, flexibility, and bivalent binding to allow avidity effects are responsible for the increased potency and breadth of dimeric 2G12. PMID:24316082

  12. Mechanism of FGF receptor dimerization and activation

    PubMed Central

    Sarabipour, Sarvenaz; Hristova, Kalina

    2016-01-01

    Fibroblast growth factors (fgfs) are widely believed to activate their receptors by mediating receptor dimerization. Here we show, however, that the FGF receptors form dimers in the absence of ligand, and that these unliganded dimers are phosphorylated. We further show that ligand binding triggers structural changes in the FGFR dimers, which increase FGFR phosphorylation. The observed effects due to the ligands fgf1 and fgf2 are very different. The fgf2-bound dimer structure ensures the smallest separation between the transmembrane (TM) domains and the highest possible phosphorylation, a conclusion that is supported by a strong correlation between TM helix separation in the dimer and kinase phosphorylation. The pathogenic A391E mutation in FGFR3 TM domain emulates the action of fgf2, trapping the FGFR3 dimer in its most active state. This study establishes the existence of multiple active ligand-bound states, and uncovers a novel molecular mechanism through which FGFR-linked pathologies can arise. PMID:26725515

  13. Metalloporphines: Dimers and Trimers.

    PubMed

    Jentzen, Walter; Shelnutt, John A; Scheidt, W Robert

    2016-06-20

    Procedures for the purification and subsequent crystallization of the slightly soluble four-coordinate metallporphines, the simplest possible porphyrin derivatives, are described. Crystals of the porphine derivatives of cobalt(II), copper(II), platinum(II), and two polymorphs of zinc(II) were obtained. Analysis of the crystal and molecular structures shows that all except the platinum(II) derivative form an unusual trimeric species in the solid state. The isomorphous cobalt(II), copper(II), and one zinc(II) polymorph pack in the unit cell to form dimers as well as the trimers. Interplanar spacings between porphine rings are similar in both the dimers and trimers and range between 3.24 and 3.37 Å. Porphine rings are strongly overlapped with lateral shifts between ring centers in both the dimers and trimers with values between 1.52 and 1.70 Å or in Category S as originally defined by Scheidt and Lee. Periodic trends in the M-Np bond distances parallel those observed previously for tetraphenyl- and octaethylporphyrin derivatives. PMID:27276239

  14. Molecular structure investigation of neutral, dimer and anion forms of 3,4-pyridinedicarboxylic acid: A combined experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Karabacak, Mehmet; Bilgili, Sibel; Atac, Ahmet

    2015-01-01

    In this study, the structural and vibrational analysis of 3,4-pyridinedicarboxylic acid (3,4-PDCA) are presented using experimental techniques as FT-IR, FT-Raman, NMR, UV and quantum chemical calculations. FT-IR and FT-Raman spectra of 3,4-pyridinedicarboxylic acid in the solid phase are recorded in the region 4000-400 cm-1 and 4000-50 cm-1, respectively. The geometrical parameters and energies of all different and possible monomer, dimer, anion-1 and anion-2 conformers of 3,4-PDCA are obtained from Density Functional Theory (DFT) with B3LYP/6-311++G(d,p) basis set. There are sixteen conformers (C1sbnd C16) for this molecule (neutral form). The most stable conformer of 3,4-PDCA is the C1 conformer. The complete assignments are performed on the basis of the total energy distribution (TED) of the vibrational modes calculated with scaled quantum mechanics (SQM) method. 1H and 13C NMR spectra are recorded and the chemical shifts are calculated by using DFT/B3LYP methods with 6-311++G(d,p) basis set. The UV absorption spectrum of the studied compound is recorded in the range of 200-400 nm by dissolved in ethanol. The optimized geometric parameters were compared with experimental data via the X-ray results derived from complexes of this molecule. In addition these, molecular electrostatic potential (MEP), thermodynamic and electronic properties, HOMO-LUMO energies and Mulliken atomic charges, are performed.

  15. Molecular structure investigation of neutral, dimer and anion forms of 3,4-pyridinedicarboxylic acid: a combined experimental and theoretical study.

    PubMed

    Karabacak, Mehmet; Bilgili, Sibel; Atac, Ahmet

    2015-01-25

    In this study, the structural and vibrational analysis of 3,4-pyridinedicarboxylic acid (3,4-PDCA) are presented using experimental techniques as FT-IR, FT-Raman, NMR, UV and quantum chemical calculations. FT-IR and FT-Raman spectra of 3,4-pyridinedicarboxylic acid in the solid phase are recorded in the region 4000-400 cm(-1) and 4000-50 cm(-1), respectively. The geometrical parameters and energies of all different and possible monomer, dimer, anion(-1) and anion(-2) conformers of 3,4-PDCA are obtained from Density Functional Theory (DFT) with B3LYP/6-311++G(d,p) basis set. There are sixteen conformers (C1C16) for this molecule (neutral form). The most stable conformer of 3,4-PDCA is the C1 conformer. The complete assignments are performed on the basis of the total energy distribution (TED) of the vibrational modes calculated with scaled quantum mechanics (SQM) method. (1)H and (13)C NMR spectra are recorded and the chemical shifts are calculated by using DFT/B3LYP methods with 6-311++G(d,p) basis set. The UV absorption spectrum of the studied compound is recorded in the range of 200-400 nm by dissolved in ethanol. The optimized geometric parameters were compared with experimental data via the X-ray results derived from complexes of this molecule. In addition these, molecular electrostatic potential (MEP), thermodynamic and electronic properties, HOMO-LUMO energies and Mulliken atomic charges, are performed. PMID:25072741

  16. Development of a Melting Curve-Based Allele-Specific PCR of Apolipoprotein E (APOE) Genotyping Method for Genomic DNA, Guthrie Blood Spot, and Whole Blood.

    PubMed

    Chen, Chia-Hsiang

    2016-01-01

    Genetic polymorphisms of apolipoprotein E (APOE) are associated with various health conditions and diseases, such as Alzheimer's disease, cardiovascular diseases, type 2 diabetes, etc. Hence, genotyping of APOE has broad applications in biomedical research and clinical settings, particularly in the era of precision medicine. The study aimed to develop a convenient and accurate method with flexible throughput to genotype the APOE polymorphisms. A melting curve-based allele-specific PCR method was developed to genotype two single nucleotide polymorphisms (SNPs) of APOE, i.e. rs429358 at codon 112 and rs7412 at codon 158. These two SNPs determine the genotype of APOE2, E3, and E4. PCR-based Sanger sequencing was used as the reference method for APOE genotyping. A 100% concordance rate was obtained in 300 subjects between the melting curve-based allele-specific PCR method and the Sanger sequencing method. This method was applied to a genetic association analysis of APOE and schizophrenia consisting of 711 patients with schizophrenia and 665 control subjects from Taiwan. However, no significant differences in the allele and genotype frequencies were detected between these two groups. Further experiments showed that DNA dissolved from blood collected on Guthrie filter paper and total blood cell lysate without DNA extraction can be used in the melting curve-based allele-specific PCR method. Thus, we suggest that this is a fast, accurate and robust APOE genotyping method with a flexible throughput and suitable for DNA template from different preparations. This convenient method shall meet the different needs of various research and clinical laboratories. PMID:27078154

  17. Evolutionary conservation of the mouse apolipoprotein e-c1-c2 gene cluster: Structure and genetic variability in inbred mice

    SciTech Connect

    Hoffer, M.J.V.; Hofker, M.H.; Eck, M.M. van; Frants, R.R. ); Havekes, L.M. )

    1993-01-01

    The human apolipoprotein E (APOE), APOC1, pseudo APOC1 (APOC1[prime]), and APOC2 genes are clustered within 48 kb on the long arm of chromosome 19. A mouse Apoe cDNA probe was used to isolate overlapping cosmid clones from a cosmid library of the C57BL/Rij inbred mouse strain. These clones were investigated for the presence of the Apocl and Apoc2 genes by heterologous hybridization. Our results show that the Apoe-cl-c2 gene cluster is conserved in the mouse. In line with evolutionary data, the mouse lacks the equivalent of APOC1[prime]. These data were confirmed using a mouse Apoc2 cDNA clone, and surprisingly the CDNA clone isolated here was 965 bp in size, which is on average 450 bp longer than other APOC2 cDNAs described so far. Correspondingly, the Apoc2 gene occupies an unusually large genomic region, due to an extended 5[prime] end. Interestingly, a variable number of tandem repeat (VNTR) in the third intron of the human APOC2 gene shows a high sequence homology and is located at the identical position in the mouse gene. Despite the high copy number of this VNTR (27 or 34 copies) only two variants were found among 11 different inbred strains. With the aid of six restriction fragment length variations in this gene cluster only two different haplotypes could be deduced, indicating that the Apoe-cl-c2 gene cluster is highly conserved in the inbred strains that were studied. 32 refs., 5 figs., 1 tab.

  18. Long-Term Effects of {sup 56}Fe Irradiation on Spatial Memory of Mice: Role of Sex and Apolipoprotein E Isoform

    SciTech Connect

    Villasana, Laura E.; Benice, Theodore S.; Raber, Jacob

    2011-06-01

    Purpose: To assess whether the effects of cranial {sup 56}Fe irradiation on the spatial memory of mice in the water maze are sex and apolipoprotein E (apoE) isoform dependent and whether radiation-induced changes in spatial memory are associated with changes in the dendritic marker microtubule-associated protein 2 (MAP-2) and the presynaptic marker synaptophysin. Methods and Materials: Two-month-old male and female mice expressing human apoE3 or apoE4 received either a 3-Gy dose of cranial {sup 56}Fe irradiation (600 MeV/amu) or sham irradiation. Mice were tested in a water maze task 13 months later to assess effects of irradiation on spatial memory retention. After behavioral testing, the brain tissues of these mice were analyzed for synaptophysin and MAP-2 immunoreactivity. Results: After irradiation, spatial memory retention of apoE3 female, but not male, mice was impaired. A general genotype deficit in spatial memory was observed in sham-irradiated apoE4 mice. Strikingly, irradiation prevented this genotype deficit in apoE4 male mice. A similar but nonsignificant trend was observed in apoE4 female mice. Although there was no change in MAP-2 immunoreactivity after irradiation, synaptophysin immunoreactivity was increased in irradiated female mice, independent of genotype. Conclusions: The effects of {sup 56}Fe irradiation on the spatial memory retention of mice are critically influenced by sex, and the direction of these effects is influenced by apoE isoform. Although in female mice synaptophysin immunoreactivity provides a sensitive marker for effects of irradiation, it cannot explain the apoE genotype-dependent effects of irradiation on the spatial memory retention of the mice.

  19. Attenuation of apoptosis by telmisartan in atherosclerotic plaques of apolipoprotein E-/- mice: evaluation using technetium 99m-annexin A5.

    PubMed

    Zhao, Yan; Zhao, Songji; Kuge, Yuji; Strauss, H William; Blankenberg, Francis G; Tamaki, Nagara

    2013-01-01

    Technetium 99m (99mTc)-annexin A5, a marker of ongoing apoptosis, is supposed to be useful in the detection of metabolically active atheroma. The aim of this study was to determine the potential of 99mTc-annexin A5 for evaluating the therapeutic effects of an angiotensin II receptor type 1 blocker (ARB) (telmisartan) on atherosclerosis. Male apolipoprotein E-/- mice were divided into telmisartan-treated (3 mg/kg/d, n  =  10) and control (n  =  10) groups. After 16 to 21 weeks of treatment, 99mTc-annexin A5 was injected and cryostat sections of aortic tissues (n  =  10-12/aorta) were prepared. The 99mTc-annexin A5 accumulation level in the plaques was evaluated by autoradiography. Serial sections of the plaques were histologically examined to identify the lesion phenotypes (normal vessels, early lesions, atheromatous lesions, and fibrotic lesions), plaque size, macrophage infiltration levels, and lipid deposition levels. Telmisartan treatment significantly decreased the plaque size (0.05 ± 0.05 vs 0.11 ± 0.08, mm2), macrophage infiltration level (0.02 ± 0.02 vs 0.03 ± 0.02, mm2), lipid deposition level (0.01 ± 0.01 vs 0.02 ± 0.02, mm2), and 99mTc-annexin A5 accumulation level (1.30 ± 1.09 vs 2.15 ± 1.91, × 10-6/g). 99mTc-annexin A5 accumulation levels in the plaques positively correlated with macrophage infiltration (r  =  .69, p < .05) and lipid deposition (r  =  .66, p < .05) levels. Apoptosis imaging with 99mTc-annexin A5 may be useful for evaluating the therapeutic effects of ARBs on atherosclerosis.

  20. Resveratrol protects against diet-induced atherosclerosis by reducing low-density lipoprotein cholesterol and inhibiting inflammation in apolipoprotein E-deficient mice

    PubMed Central

    Chang, Geng-Ruei; Chen, Po-Lin; Hou, Po-Hsun; Mao, Frank Chiahung

    2015-01-01

    Objective(s): Resveratrol (RES) is a polyphenol compound that has been shown a promising cardioprotective effect. However, some reports have yielded conflicting findings. Herein, we investigated the anti-atherosclerotic effects of RES in apolipoprotein E (apo E)-deficient mice on a high cholesterol diet. Materials and Methods: Firstly, atherosclerosis was induced by feeding a high cholesterol diet to apo E-deficient mice. Then, we examined its effects on weight control, and serum interleukin-6 (IL-6) levels and used histopathological methods to analyze morphology and inflammatory marker of atherosclerotic lesions in mice orally supplemented with high (25 mg/kg/day) and low (5 mg/kg/day) doses of RES for 8 weeks. Results: Mice with high dose of RES had reduced epididymal fat pads, and lower serum IL-6 levels compared with those of control mice. Moreover, RES in high doses also decreased the low-density lipoprotein cholesterol (LDL-C) levels and atherogenic index (LDL-C/HDL-C) in the mice. Dissection of high-dose RES-treated mice revealed a marked reduction in fat deposition, percentage of mice with atherosclerotic lesion, and intima/media ratio in the aortic areas. The expressions of macrophage-specific marker F4/80 and cardiovascular inflammatory marker NF-κB in atherosclerotic vessels were both diminished in the atherosclerotic vessels of high-dose RES-supplementated apo E-deficient mice. Conclusion: These results suggest that RES prevented the effects of a high cholesterol diet on the rate of accretion in atherosclerosis progression by reducing the LDL-C levels and suppressing atherosclerotic inflammation. RES can therefore be valuable in the development of new anti-atherosclerotic agents. PMID:26949492

  1. H1-antihistamines exacerbate high-fat diet-induced hepatic steatosis in wild-type but not in apolipoprotein E knockout mice.

    PubMed

    Raveendran, Vineesh V; Kassel, Karen M; Smith, Donald D; Luyendyk, James P; Williams, Kurt J; Cherian, Rachel; Reed, Gregory A; Flynn, Colleen A; Csanaky, Iván L; Lickteig, Andrew L; Pratt-Hyatt, Matthew J; Klaassen, Curtis D; Dileepan, Kottarappat N

    2014-07-15

    We examined the effects of two over-the-counter H1-antihistamines on the progression of fatty liver disease in male C57Bl/6 wild-type and apolipoprotein E (ApoE)-/- mice. Mice were fed a high-fat diet (HFD) for 3 mo, together with administration of either cetirizine (4 mg/kg body wt) or fexofenadine (40 mg/kg body wt) in drinking water. Antihistamine treatments increased body weight gain, gonadal fat deposition, liver weight, and hepatic steatosis in wild-type mice but not in ApoE-/- mice. Lobular inflammation, acute inflammation, and necrosis were not affected by H1-antihistamines in either genotype. Serum biomarkers of liver injury tended to increase in antihistamine-treated wild-type mice. Serum level of glucose was increased by fexofenadine, whereas lipase was increased by cetirizine. H1-antihistamines reduced the mRNA expression of ApoE and carbohydrate response element-binding protein in wild-type mice, without altering the mRNA expression of sterol regulatory element-binding protein 1c, fatty acid synthase, or ApoB100, in either genotype. Fexofenadine increased both triglycerides and cholesterol ester, whereas cetirizine increased only cholesterol ester in liver, with a concomitant decrease in serum triglycerides by both antihistamines in wild-type mice. Antihistamines increased hepatic levels of conjugated bile acids in wild-type mice, with the effect being significant in fexofenadine-treated animals. The increase was associated with changes in the expression of organic anion transport polypeptide 1b2 and bile salt export pump. These results suggest that H1-antihistamines increase the progression of fatty liver disease in wild-type mice, and there seems to be an association between the severity of disease, presence of ApoE, and increase in hepatic bile acid levels.

  2. Effect of n-3 fatty acids on serum lipid levels and hepatic fatty acid metabolism in BALB/c.KOR-Apoeshl mice deficient in apolipoprotein E expression.

    PubMed

    Ide, Takashi; Takahashi, Yoko; Kushiro, Masayo; Tachibana, Masayoshi; Matsushima, Yoshibumi

    2004-03-01

    N-3 fatty acids exert a potent serum lipid-lowering effect in rodents mainly by affecting hepatic fatty acid oxidation and synthesis. However, it has been observed that fish oil and docosahexaenoic acid ethyl ester do not lower serum lipid levels in apolipoprotein E (apoE)-knockout (Apoetm1Unc) mice generated by gene targeting. To test the hypothesis that apoE expression is required for n-3 fatty acid-dependent regulation of serum lipid levels and hepatic fatty acid metabolism, we examined the effect of fish oil and n-3 fatty acid ethyl esters on the activity and gene expression of hepatic enzymes involved in fatty acid oxidation and synthesis using an alternative apoE-deficient mouse model with the BALB/c genetic background (BALB/c.KOR-Apoeshl). ApoE-deficient mice were fed diets containing 9.4% palm oil, fish oil, or 5.4% palm oil and 1% EPA plus 3% DHA ethyl esters for 15 days. In contrast to the reported data on apoE-knockout mice, fish oil and n-3 fatty acid ethyl esters greatly decreased serum triacylglycerol, cholesterol, and phospholipid levels in the Apoeshl mice. The decreases were greater with fish oil than with ethyl esters. The alterations by dietary n-3 fatty acids of serum lipid levels were accompanied by parallel changes in the activity and mRNA levels of enzymes involved in hepatic fatty acid oxidation and synthesis. The reason for the discrepancy between the results of the current study and previous studies is unknown. However, our study at least indicates that a lack of apoE expression does not necessarily accompany deficits in the n-3 fatty acid-dependent regulation of serum lipid levels and hepatic fatty acid metabolism.

  3. Ultrasound Biomicroscopic Imaging for Interleukin-1 Receptor Antagonist-Inhibiting Atherosclerosis and Markers of Inflammation in Atherosclerotic Development in Apolipoprotein-E Knockout Mice.

    PubMed

    Li, Rong-Juan; Sun, Yan; Wang, Qin; Yang, Jiao; Yang, Ya; Song, Li; Wang, Zheng; Luo, Xiang-Hong; Su, Rui-Juan

    2015-08-01

    We sought to validate the hypothesis that the development of atherosclerosis can be suppressed by the interleukin-1 receptor antagonist (IL-1Ra) in murine models of atherosclerosis in vivo, noninvasively seen by means of high-resolution ultrasound biomicroscopy, and we studied changes in inflammatory markers such as IL-1 and C-reactive protein (CRP) plasma levels in these models of atherosclerosis. We divided IL-1Ra(+/-)/apolipoprotein-E (apoE)(-/-) and IL-1Ra(+/+)/apoE(-/-) mice into 2 age groups, used as atherosclerotic models. The control groups were age-matched IL-1Ra(+/+)/apoE(+/+) mice. Plaque thickness was measured in the ascending aorta in short-axis images by means of ultrasound and histology. Plasma levels of IL-1 and CRP were quantified in the 3 murine groups. At 16 weeks, plaque thickness in the ascending aortas of the IL-1Ra(+/-)/apoE(-/-) mice was significantly greater than that in the IL-1Ra(+/+)/apoE(-/-) mice, on ultrasound and histology (P <0.01). In contrast, at 32 weeks, the differences between these 2 genotypes were not statistically significant. Serum IL-1 levels were lower in the IL-1Ra(+/-)/apoE(-/-) mice than in the IL-1Ra(+/+)/apoE(-/-) mice at 16 and 32 weeks (P <0.05). At 16 weeks, serum CRP levels in the IL-1Ra(+/-)/apoE(-/-) mice were higher than in the IL-1Ra(+/+)/apoE(-/-) mice (P <0.01). Our results suggest that ultrasound biomicroscopy enables evaluation of atherosclerotic lesions in vivo, noninvasively and in real-time, in apoE(-/-) mice. Partial IL-1Ra deficiencies might promote early plaque development in 16-week-old apoE(-/-) mice. The balance of IL-1 and IL-1Ra might influence atherosclerotic development. Finally, CRP might affect the initiation of atherosclerosis, rather than its progression.

  4. Plasma S-adenosylhomocysteine is a better biomarker of atherosclerosis than homocysteine in apolipoprotein E-deficient mice fed high dietary methionine.

    PubMed

    Liu, Chi; Wang, Qing; Guo, Honghui; Xia, Min; Yuan, Qin; Hu, Yan; Zhu, Huilian; Hou, Mengjun; Ma, Jing; Tang, Zhihong; Ling, Wenhua

    2008-02-01

    Homocysteine (Hcy) and S-adenosylhomocysteine (AdoHcy) are critical intermediates of methionine metabolism. To investigate which, if either, of these compounds is more closely related to atherosclerosis, we fed 5 groups of apolipoprotein E (apoE)-deficient mice different diets for 8 wk to induce changes in their plasma Hcy and AdoHcy concentrations. These included an AIN-93G control diet (C), this C diet supplemented with methionine (M), the M diet deficient in folates, vitamin B-6, and vitamin B-12 (M-V), this M diet supplemented with these B vitamins (M+V), and a C diet deficient in B vitamins (C-V). Compared with controls, mice fed the C-V diet had a moderate elevation in their plasma total Hcy (tHcy) levels; however, their plasma AdoHcy concentration and atherosclerotic lesion areas were not different. In contrast, the mice fed the M+V diet had larger atherosclerotic lesion areas and elevated plasma AdoHcy concentrations but their plasma tHcy concentration did not differ from that of the group C mice. The plasma AdoHcy concentration and aortic sinus lesion areas were positively correlated (r = 0.866; P < 0.001). We observed a negative correlation between the plasma AdoHcy concentration and both the DNA methyltransferase activity (r = -0.792; P < 0.001) and global DNA methylation status (r = -0.824; P < 0.001) in the aortic tissue. Hence, our study suggests that plasma AdoHcy is a better biomarker of atherosclerosis than Hcy and may accelerate the development of atherosclerotic lesions in apoE-deficient mice that have been fed a high methionine diet. The mechanisms underlying this effect may be related to the AdoHcy-mediated inhibition of DNA methylation in the aortic tissue. PMID:18203897

  5. Plasma Lipidomic Profiling in a Military Population of Mild Traumatic Brain Injury and Post-Traumatic Stress Disorder with Apolipoprotein E ɛ4-Dependent Effect.

    PubMed

    Emmerich, Tanja; Abdullah, Laila; Crynen, Gogce; Dretsch, Michael; Evans, James; Ait-Ghezala, Ghania; Reed, Jon; Montague, Hannah; Chaytow, Helena; Mathura, Venkatarajan; Martin, Justin; Pelot, Robert; Ferguson, Scott; Bishop, Alex; Phillips, John; Mullan, Michael; Crawford, Fiona

    2016-07-15

    In the military population, there is high comorbidity between mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) due to the inherent risk of psychological trauma associated with combat. These disorders present with long-term neurological dysfunction and remain difficult to diagnose due to their comorbidity and overlapping clinical presentation. Therefore, we performed cross-sectional analysis of blood samples from demographically matched soldiers (total, n = 120) with mTBI, PTSD, and mTBI+PTSD and those who were considered cognitively and psychologically normal. Soldiers were genotyped for apolipoprotein E (APOE) ɛ4, and phospholipids (PL) were examined using liquid chromatography/mass spectrometry analysis. We observed significantly lower levels of several major PL classes in TBI, PTSD, and TBI+PTSD, compared with controls. PTSD severity analysis revealed that significant PL decreases were primarily restricted to the moderate-to-severe PTSD group. An examination of the degree of unsaturation showed that monounsaturated fatty acid-containing phosphatidylcholine (PC) and phosphatidylinositol (PI) species were lower in the TBI and TBI+PTSD groups. However, these PLs were unaltered among PTSD subjects, compared with controls. Similarly, ether PC (ePC) levels were lower in PTSD and TBI+PTSD subjects, relative to controls. Ratios of arachidonic acid (AA) to docosahexaenoic acid (DHA)-containing species were significantly decreased within PC and phosphatidylethanolamine (PE) classes. APOE ɛ4 (+) subjects exhibited higher PL levels than their APOE ɛ4 (-) counterparts within the same diagnostic groups. These findings suggest that PL profiles, together with APOE genotyping, could potentially aid to differentiate diagnosis of mTBI and PTSD and warrant further validation. In conclusion, PL profiling may facilitate clinical diagnosis of mTBI and PTSD currently hindered by comorbid pathology and overlapping symptomology of these two conditions.

  6. Direct demonstration of P-selectin- and VCAM-1-dependent mononuclear cell rolling in early atherosclerotic lesions of apolipoprotein E-deficient mice.

    PubMed

    Ramos, C L; Huo, Y; Jung, U; Ghosh, S; Manka, D R; Sarembock, I J; Ley, K

    1999-06-11

    Apolipoprotein E-deficient (ApoE-/-) mice develop atherosclerotic lesions throughout the arterial tree, including the carotid bifurcation. Although the expression of adhesion molecules such as ICAM-1, vascular cell adhesion molecule-1 (VCAM-1), and P-selectin on endothelium that overlie atherosclerotic plaques has been implicated in monocyte recruitment to developing lesions, monocyte adhesion in atherosclerotic vessels has not been observed directly. To investigate which adhesion molecules may be important in monocyte adhesion to atherosclerotic lesions, an isolated mouse carotid artery preparation was developed and perfused with mononuclear cells. We show rolling and attachment of the human monocytic cell line U937 and the mouse monocyte-macrophage cell line P388D1 in carotid arteries from 10- to 12-week-old ApoE-/- and C57BL/6 wild-type mice fed a Western-type diet (21% fat wt/wt) for 4 to 5 weeks. No rolling was observed in carotid arteries from C57BL/6 or BALB/c wild-type mice fed a chow diet and little was observed in BALB/c mice fed a Western-type diet. This model represents early lesion development as shown by minimal macrophage infiltration in the intima of carotid arteries from ApoE-/- mice fed a Western-type diet. Rolling was observed at shear stresses that were characteristic of the low-shear recirculation zone near the carotid bifurcation. Mononuclear cell attachment and rolling were significantly inhibited by monoclonal antibody blockade of P-selectin or its leukocyte ligand P-selectin glycoprotein ligand-1. Rolling velocities increased after monoclonal antibody blockade of mononuclear cell alpha4-integrin or VCAM-1, which indicates that alpha4-integrin interacting with VCAM-1 stabilizes rolling interactions and prolongs monocyte transit times.

  7. Antiatherosclerotic Effects of 1-Methylnicotinamide in Apolipoprotein E/Low-Density Lipoprotein Receptor-Deficient Mice: A Comparison with Nicotinic Acid.

    PubMed

    Mateuszuk, Lukasz; Jasztal, Agnieszka; Maslak, Edyta; Gasior-Glogowska, Marlena; Baranska, Malgorzata; Sitek, Barbara; Kostogrys, Renata; Zakrzewska, Agnieszka; Kij, Agnieszka; Walczak, Maria; Chlopicki, Stefan

    2016-02-01

    1-Methylnicotinamide (MNA), the major endogenous metabolite of nicotinic acid (NicA), may partially contribute to the vasoprotective properties of NicA. Here we compared the antiatherosclerotic effects of MNA and NicA in apolipoprotein E (ApoE)/low-density lipoprotein receptor (LDLR)-deficient mice. ApoE/LDLR(-/-) mice were treated with MNA or NicA (100 mg/kg). Plaque size, macrophages, and cholesterol content in the brachiocephalic artery, endothelial function in the aorta, systemic inflammation, platelet activation, as well as the concentration of MNA and its metabolites in plasma and urine were measured. MNA and NicA reduced atherosclerotic plaque area, plaque inflammation, and cholesterol content in the brachiocephalic artery. The antiatherosclerotic actions of MNA and NicA were associated with improved endothelial function, as evidenced by a higher concentration of 6-keto-prostaglandin F1 α and nitrite/nitrate in the aortic ring effluent, inhibition of platelets (blunted thromboxane B2 generation), and inhibition of systemic inflammation (lower plasma concentration of serum amyloid P, haptoglobin). NicA treatment resulted in an approximately 2-fold higher concentration of MNA and its metabolites in urine and a 4-fold higher nicotinamide/MNA ratio in plasma, compared with MNA treatment. In summary; MNA displays pronounced antiatherosclerotic action in ApoE/LDLR(-/-) mice, an effect associated with an improvement in prostacyclin- and nitric oxide-dependent endothelial function, inhibition of platelet activation, inhibition of inflammatory burden in plaques, and diminished systemic inflammation. Despite substantially higher MNA availability after NicA treatment, compared with an equivalent dose of MNA, the antiatherosclerotic effect of NicA was not stronger. We suggest that detrimental effects of NicA or its metabolites other than MNA may limit beneficial effects of NicA-derived MNA.

  8. Apolipoprotein E knockout mice have accentuated malnutrition with mucosal disruption and blunted insulin-like growth factor I responses to refeeding.

    PubMed

    Oriá, Reinaldo B; Vieira, Carlos Meton G; Pinkerton, Relana C; de Castro Costa, Carlos M; Lopes, Maria Beatriz; Hussaini, Isa; Shi, Weibin; Brito, Gerly A C; Lima, Aldo A M; Guerrant, Richard L

    2006-08-01

    Apolipoprotein E (apoE) is synthesized mainly in the liver and in the brain and is critical for cholesterol metabolism and recovery from brain injury. However, although apoE mRNA increases at birth, during suckling, and after fasting in rat liver, little is known about its role in early postnatal development. Using an established postnatal malnutrition model and apoE knock-out (ko) mice, we examined the role of apoE in intestinal adaptation responses to early postnatal malnutrition. Wild-type and apoE-ko mice were separated from their lactating dams for defined periods each day (4 hours on day 1, 8 hours on day 2, and 12 hours thereafter). We found significant growth deficits, as measured by weight gain or tail length, in the apoE-ko mice submitted to a malnutrition challenge, as compared with malnourished wild type, especially during the second week of postnatal development (P < .05). In addition, apoE-ko animals failed to show growth catch-up after refeeding, compared with wild-type malnourished controls. Furthermore, we found shorter crypts and reduced villus height and area in the apoE-ko malnourished mice, compared with controls, after refeeding. Insulinlike growth factor 1 expression was also blunted in the ileum in apoE-ko mice after refeeding, compared with wild-type controls, which exhibited full insulinlike growth factor 1 expression along the intestinal crypts, villi, and in the muscular layer. Taken together, these findings suggest the importance of apoE in coping with a malnutrition challenge and during the intestinal adaptation after refeeding.

  9. Apolipoprotein E gene ε4ε4 is associated with elevated risk of primary open angle glaucoma in Asians: a meta-analysis

    PubMed Central

    2014-01-01

    Background Epidemiological studies have evaluated the association between Apolipoprotein E (APOE) gene ε2/ε3/ε4 polymorphism and glaucoma susceptibility. However, the published data are still inconclusive. The aim of the present study is to evaluate the impact of APOE gene ε2/ε3/ε4 polymorphism on glaucoma risk by using meta-analysis. Methods A comprehensive literature search of PubMed, EMBASE, Cochrane, Elsevier Science Direct and CNKI databases was conducted to identify relevant articles, with the last report up to January 5, 2014. Pooled odds ratio (OR) and 95% confidence interval (CI) were used to assess the strength of association by using the fixed or random effect model. Results Fifteen separate studies including 2,700 cases and 2,365 controls were included in the meta-analysis. We did not detect a significant association between APOE gene ε2/ε3/ε4 polymorphism and glaucoma in overall population (P > 0.0083). In Asians, we detected an association of the ε4ε4 genotype with elevated risk for glaucoma (OR = 5.22, 95% CI = 1.85-14.68, P = 0.002), mainly for primary open angle glaucoma (OR = 4.98, 95% CI = 1.75-14.20, P = 0.003). Conclusions The meta-analysis suggests that APOE gene ε4ε4 may be associated with elevated risk for primary open angle glaucoma in Asians. However, more epidemiologic studies based on larger sample size, case–control design and stratified by ethnicity as well as types of glaucoma are suggested to further clarify the relationship between APOE gene ε2/ε3/ε4 polymorphism and genetic predisposition to glaucoma. PMID:24885013

  10. Paraoxonase 1 gene transfer lowers vascular oxidative stress and improves vasomotor function in apolipoprotein E-deficient mice with pre-existing atherosclerosis

    PubMed Central

    Guns, P-J; Van Assche, T; Verreth, W; Fransen, P; Mackness, B; Mackness, M; Holvoet, P; Bult, H

    2007-01-01

    Background and purpose: Transgenesis of human paraoxonase 1 (PON1), a HDL-associated enzyme that destroys lipid peroxides, has been reported to reduce early atherogenesis in mice. The present study explored the therapeutic potential of human PON1 gene transfer in old apolipoprotein E-deficient (apoE−/−) mice with advanced atherosclerosis. Experimental approach: ApoE−/− mice (18 months, regular chow) were transfected with PON1 adenovirus (AdPON1, n=10) or control adenovirus (AdRR5, n=10). Non-transfected apoE−/− (n=9) and C57Bl/6J (WT, n=6) mice served as controls. Three weeks later, plaque size and composition, and endothelial cell (EC) and smooth muscle cell (SMC) function were assessed in the aorta. Key results: PON1 gene transfer raised total PON1 serum activity 13-15 fold during the 3-week study period, without affecting hypercholesterolaemia or lesion size. However, PON1 decreased the oxLDL content of the plaque. Plaque-free thoracic aorta rings from apoE−/− mice displayed, like rings from WT mice, complete relaxation to acetylcholine (ACh, 86±2%), ATP (90±2%) or UTP (83±3%). In contrast, in plaque-bearing segments amplitude (55±7%, 68±8%, 52±8% respectively) and sensitivity were decreased. EC function was completely (ATP, UTP) or largely (ACh) restored by AdPON1. Furthermore, apoE−/− SMCs released less intracellular calcium than WT upon sarco-endoplasmic reticulum calcium ATPase (SERCA) inhibition by cyclopiazonic acid. This defect was also restored by AdPON1 transfection. Conclusions and implications: These data indicate that AdPON1 gene transfer improved vascular wall oxidative stress, EC function, and SMC Ca2+ homeostasis in segments with pre-existing atherosclerosis, independently of an effect on plaque size. PMID:18059326

  11. Apolipoprotein E-dependent inverse regulation of vertebral bone and adipose tissue mass in C57Bl/6 mice: modulation by diet-induced obesity.

    PubMed

    Bartelt, Alexander; Beil, F Timo; Schinke, Thorsten; Roeser, Kerstin; Ruether, Wolfgang; Heeren, Joerg; Niemeier, Andreas

    2010-10-01

    The long prevailing view that obesity is generally associated with beneficial effects on the skeleton has recently been challenged. Apolipoprotein E (apoE) is known to influence both adipose tissue and bone. The goal of the current study was to examine the impact of apoE on the development of fat mass and bone mass in mice under conditions of diet-induced obesity (DIO). Four week-old male C57BL/6 (WT) and apoE-deficient (apoE(-/-)) mice received a control or a diabetogenic high-fat diet (HFD) for 16 weeks. The control-fed apoE(-/-) animals displayed less total fat mass and higher lumbar trabecular bone volume (BV/TV) than WT controls. When stressed with HFD to induce obesity, apoE(-/-) mice had a lower body weight, lower serum glucose, insulin and leptin levels and accumulated less white adipose tissue mass at all sites including bone marrow. While WT animals showed no significant change in BV/TV and bone formation rate (BFR), apoE deficiency led to a decrease of BV/TV and BFR when stressed with HFD. Bone resorption parameters were not affected by HFD in either genotype. Taken together, under normal dietary conditions, apoE-deficient mice acquire less fat mass and more bone mass than WT littermates. When stressed with HFD to develop DIO, the difference of total body fat mass becomes larger and the difference of bone mass smaller between the genotypes. We conclude that apoE is involved in an inverse regulation of bone mass and fat mass in growing mice and that this effect is modulated by diet-induced obesity. PMID:20633710

  12. Ultrasound Biomicroscopic Imaging for Interleukin-1 Receptor Antagonist-Inhibiting Atherosclerosis and Markers of Inflammation in Atherosclerotic Development in Apolipoprotein-E Knockout Mice.

    PubMed

    Li, Rong-Juan; Sun, Yan; Wang, Qin; Yang, Jiao; Yang, Ya; Song, Li; Wang, Zheng; Luo, Xiang-Hong; Su, Rui-Juan

    2015-08-01

    We sought to validate the hypothesis that the development of atherosclerosis can be suppressed by the interleukin-1 receptor antagonist (IL-1Ra) in murine models of atherosclerosis in vivo, noninvasively seen by means of high-resolution ultrasound biomicroscopy, and we studied changes in inflammatory markers such as IL-1 and C-reactive protein (CRP) plasma levels in these models of atherosclerosis. We divided IL-1Ra(+/-)/apolipoprotein-E (apoE)(-/-) and IL-1Ra(+/+)/apoE(-/-) mice into 2 age groups, used as atherosclerotic models. The control groups were age-matched IL-1Ra(+/+)/apoE(+/+) mice. Plaque thickness was measured in the ascending aorta in short-axis images by means of ultrasound and histology. Plasma levels of IL-1 and CRP were quantified in the 3 murine groups. At 16 weeks, plaque thickness in the ascending aortas of the IL-1Ra(+/-)/apoE(-/-) mice was significantly greater than that in the IL-1Ra(+/+)/apoE(-/-) mice, on ultrasound and histology (P <0.01). In contrast, at 32 weeks, the differences between these 2 genotypes were not statistically significant. Serum IL-1 levels were lower in the IL-1Ra(+/-)/apoE(-/-) mice than in the IL-1Ra(+/+)/apoE(-/-) mice at 16 and 32 weeks (P <0.05). At 16 weeks, serum CRP levels in the IL-1Ra(+/-)/apoE(-/-) mice were higher than in the IL-1Ra(+/+)/apoE(-/-) mice (P <0.01). Our results suggest that ultrasound biomicroscopy enables evaluation of atherosclerotic lesions in vivo, noninvasively and in real-time, in apoE(-/-) mice. Partial IL-1Ra deficiencies might promote early plaque development in 16-week-old apoE(-/-) mice. The balance of IL-1 and IL-1Ra might influence atherosclerotic development. Finally, CRP might affect the initiation of atherosclerosis, rather than its progression. PMID:26413013

  13. Antiatherosclerotic Effects of 1-Methylnicotinamide in Apolipoprotein E/Low-Density Lipoprotein Receptor-Deficient Mice: A Comparison with Nicotinic Acid.

    PubMed

    Mateuszuk, Lukasz; Jasztal, Agnieszka; Maslak, Edyta; Gasior-Glogowska, Marlena; Baranska, Malgorzata; Sitek, Barbara; Kostogrys, Renata; Zakrzewska, Agnieszka; Kij, Agnieszka; Walczak, Maria; Chlopicki, Stefan

    2016-02-01

    1-Methylnicotinamide (MNA), the major endogenous metabolite of nicotinic acid (NicA), may partially contribute to the vasoprotective properties of NicA. Here we compared the antiatherosclerotic effects of MNA and NicA in apolipoprotein E (ApoE)/low-density lipoprotein receptor (LDLR)-deficient mice. ApoE/LDLR(-/-) mice were treated with MNA or NicA (100 mg/kg). Plaque size, macrophages, and cholesterol content in the brachiocephalic artery, endothelial function in the aorta, systemic inflammation, platelet activation, as well as the concentration of MNA and its metabolites in plasma and urine were measured. MNA and NicA reduced atherosclerotic plaque area, plaque inflammation, and cholesterol content in the brachiocephalic artery. The antiatherosclerotic actions of MNA and NicA were associated with improved endothelial function, as evidenced by a higher concentration of 6-keto-prostaglandin F1 α and nitrite/nitrate in the aortic ring effluent, inhibition of platelets (blunted thromboxane B2 generation), and inhibition of systemic inflammation (lower plasma concentration of serum amyloid P, haptoglobin). NicA treatment resulted in an approximately 2-fold higher concentration of MNA and its metabolites in urine and a 4-fold higher nicotinamide/MNA ratio in plasma, compared with MNA treatment. In summary; MNA displays pronounced antiatherosclerotic action in ApoE/LDLR(-/-) mice, an effect associated with an improvement in prostacyclin- and nitric oxide-dependent endothelial function, inhibition of platelet activation, inhibition of inflammatory burden in plaques, and diminished systemic inflammation. Despite substantially higher MNA availability after NicA treatment, compared with an equivalent dose of MNA, the antiatherosclerotic effect of NicA was not stronger. We suggest that detrimental effects of NicA or its metabolites other than MNA may limit beneficial effects of NicA-derived MNA. PMID:26631491

  14. Apolipoprotein E4 impairs in vivo hippocampal long-term synaptic plasticity by reducing the phosphorylation of CaMKIIα and CREB.

    PubMed

    Qiao, Feng; Gao, Xiu-Ping; Yuan, Li; Cai, Hong-Yan; Qi, Jin-Shun

    2014-01-01

    Inheritance of the apolipoprotein E genotype ε4 (APOE4) is a powerful risk factor for most cases of late-onset Alzheimer's disease (AD). However, the effects of ApoE4 on the long-term synaptic plasticity and its underlying mechanism have not clearly investigated. In the present study, we examined the effects of ApoE4 on the hippocampal late-phase long-term potentiation (L-LTP) and investigated its probable molecular mechanisms by using in vivo field potential recording, immunohistochemistry, and western blotting. The results showed that: (1) intra-hippocampal injection of 0.2 μg ApoE4, but not ApoE2, before high frequency stimulations (HFSs) attenuated the induction of hippocampal L-LTP in the CA1 region, while injection of the same concentration of ApoE4 after HFSs, even at a higher concentration (2 μg), did not affect the long term synaptic plasticity; (2) ApoE4 injection did not affect the paired pulse facilitation in the hippocampal CA1 region; (3) ApoE4 injection before, not after, HFSs significantly decreased the levels of phosphorylated Ca2+/calmodulin-dependent protein kinase IIα (p-CaMKIIα) and phosphorylated cAMP response element-binding protein (p-CREB) in the hippocampus. These results demonstrated for the first time that ApoE4 could impair hippocampal L-LTP by reducing p-CaMKIIα and p-CREB, suggesting that the ApoE4-induced suppression of hippocampal long-term synaptic plasticity may contribute to the cognitive impairments in genetic AD; and both CaMKIIα and CREB are important intracellular targets of the neurotoxic ApoE4.

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

    PubMed

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

    2014-01-01

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

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

    PubMed

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

    2013-05-01

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

  17. The apolipoprotein E4 allele is not associated with an abnormal lipid profile in a Native American population following its traditional lifestyle.

    PubMed

    Aguilar, C A; Talavera, G; Ordovas, J M; Barriguete, J A; Guillén, L E; Leco, M E; Pedro-Botet, J; Gonzalez-Barranco, J; Gómez-Pérez, F J; Rull, J A

    1999-02-01

    The apolipoprotein E4 allele is associated in industrialized countries with an elevated LDL cholesterol concentration and an increased cardiovascular risk. Our purpose in this study was to assess the influence of the genetic variation at the APOE gene locus on the lipid profile of a Native American rural population. We examined plasma lipid levels and the common apo E alleles in 142 healthy randomly selected adults living in their native communities in western Mexico. Their age was 38+/-17 years and the BMI 25.7+/-4.5 kg/m2. Plasma cholesterol, triglycerides, LDL C and HDL C were 165+/-29.6, 126+/-83, 98+/-26 and 42+/-12.7 mg/dl respectively. Ninety-one per cent of the subjects had Lp(a) concentrations below 20 mg/dl and 30% had levels lower than 2 mg/dl. The most common APOE genotype was E3/3 (63%), followed by E3/4 (30.1%). The prevalence of the E2 allele was very low (2.3%). No difference was observed in LDL C concentrations between the E3/E3 and E3/E4 subjects; however carriers of the E2/3 genotype had lower LDL C levels. Similar results were obtained for cholesterol and apo B levels. In summary, the increased LDL C levels associated with the E4 allele in previous studies were not observed in a population with non-westernized habits. Environmental factors, such as diet and lifestyle, could outweigh the hypercholesterolemic predisposition resulting from the presence of the apo E4 allele.

  18. Quantitative Trait Loci Affecting Atherosclerosis at the Aortic Root Identified in an Intercross between DBA2J and 129S6 Apolipoprotein E-Null Mice

    PubMed Central

    Kayashima, Yukako; Tomita, Hirofumi; Zhilicheva, Svetlana; Kim, Shinja; Kim, Hyung-Suk; Bennett, Brian J.; Maeda, Nobuyo

    2014-01-01

    Apolipoprotein E-null mice on a DBA/2J genetic background (DBA-apoE) are highly susceptible to atherosclerosis in the aortic root area compared with those on a 129S6 background (129-apoE). To explore atherosclerosis-responsible genetic regions, we performed a quantitative trait locus (QTL) analysis using 172 male and 137 female F2 derived from an intercross between DBA-apoE and 129-apoE mice. A genome-wide scan identified two significant QTL for the size of lesions at the root: one is Ath44 on Chromosome (Chr) 1 at 158 Mb, and the other Ath45 on Chr 2 at 162 Mb. Ath44 co-localizes with but appears to be independent of a previously reported QTL, Ath1, while Ath45 is a novel QTL. DBA alleles of both Ath44 and Ath45 confer atherosclerosis-susceptibility. In addition, a QTL on Chr 14 at 73 Mb was found significant only in males, and 129 allele conferring susceptibility. Further analysis detected female-specific interactions between a second QTL on Chr 1 at 73 Mb and a QTL on Chr 3 at 21 Mb, and between Chr 7 at 84 Mb and Chr 12 at 77 Mb. These loci for the root atherosclerosis were independent of QTLs for plasma total cholesterol and QTLs for triglycerides, but a QTL for HDL (Chr 1 at 126 Mb) overlapped with the Ath44. Notably, haplotype analysis among 129S6, DBA/2J and C57BL/6 genomes and their gene expression data narrowed the candidate regions for Ath44 and Ath45 to less than 5 Mb intervals where multiple genome wide associations with cardiovascular phenotypes have also been reported in humans. SNPs in or near Fmo3, Sele and Selp for Ath44, and Lbp and Pkig for Ath45 were suggested for further investigation as potential candidates underlying the atherosclerosis susceptibility. PMID:24586312

  19. Association of the apolipoprotein E {epsilon}4 allele with clinical subtypes of autopsy-confirmed Alzheimer`s Disease

    SciTech Connect

    Zubenko, G.S.; Stiffler, S.; Kopp, U.

    1994-09-15

    Consistent with previous reports, we observed a significant association of the APOE {epsilon}4 allele with Alzheimer`s Disease (AD) in a series of 91 autopsy-confirmed cases. The {epsilon}4 allele frequency was higher in cases with a family history of AD-like dementia (0.54 {+-} 0.07), although the {epsilon}4 allele frequency in the AD cases with a negative family history (0.38 {+-} 0.05) remained significantly greater than that for the non-AD control group (0.13 {+-} 0.03). A similar increase in {epsilon}4 allele frequency (0.54 {+-} 0.07) was observed in the AD cases with amyloid angiopathy, compared to those who did not have amyloid angiopathy (0.35 {+-} 0.04). Contrary to previous reports, no effect of the dosage of the {epsilon}4 allele was found on the age of onset of dementia among the AD cases and, contrary to reports suggesting an association of {epsilon}4 and atherosclerosis, the {epsilon}4 allele frequency was similar in cases with or without concurrent brain infarcts. Modest but consistent correlations were observed between the dosage of {epsilon}4 alleles and the cortical density of senile plaques, but not neurofibrillary tangles. The last finding suggests that the pathogenic events mediated by the {epsilon}4 allele may be more directly involved in the formation of senile plaques, the identifying lesions in AD, than neurofibrillary tangles. A robust association of both the presence of an {epsilon}4 allele and a family history of AD-like dementia with concurrent amyloid angiopathy occurred within our sample of AD cases. This association arose from an interaction of the {epsilon}4 allele with a separate familial factor for which a family history of dementia served as a surrogate. These results suggest that amyloid angiopathy may be a common or central feature of a form of familial AD that is associated with the transmission of the APOE {epsilon}4 allele. 22 refs., 2 figs., 5 tabs.

  20. Structure determination of functional membrane proteins using small-angle neutron scattering (sans) with small, mixed-lipid liposomes: native beef heart mitochondrial cytochrome c oxidase forms dimers.

    PubMed

    Rubinson, Kenneth A; Pokalsky, Christine; Krueger, Susan; Prochaska, Lawrence J

    2013-01-01

    The low-resolution three-dimensional structure of purified native beef heart mitochondrial cytochrome c oxidase (COX) in asolectin unilamellar liposomes has been measured by small-angle neutron scattering under the conditions where the protein remains fully functional. From a neutron scattering perspective, the use of mixed-lipid liposomes provided for a more homogeneous matrix than can be achieved using a single lipid. As a result, the measurements were able to be performed under conditions where the liposome scattering was essentially eliminated (contrast-matched conditions). The protein structure in the membrane was modeled as a simple parallelepiped with side lengths of (59 × 70 × 120) Å with uncertainties, respectively, (11, 12, 20 Å). The molecular mass calculated for a typical protein with this volume is estimated to be (410 ± 124) kDa, which indicates the mass of a COX dimer. The longest dimension has some uncertainty due to intermolecular scattering contributing to the data. Nevertheless, that length was estimated using an average protein density and the known dimer molecular mass. Using the same cross sectional dimensions for the structure, the length is estimated to be 120 Å. However, the measured scattering curve of the dimer in the liposome differs significantly from that calculated from the X-ray structure of the dimer in a crystal of mixed micelles (PDB 3AG1). The calculated SANS scattering from the crystal structure was fit with a parallelepiped, measuring (59 × 101 × 129) Å with fitting uncertainties, respectively, (2, 3, 3 Å). Our results suggest that COX is a functional dimer when reconstituted into mixed-lipid liposomes.

  1. RecFOR is not required for pneumococcal transformation but together with XerS for resolution of chromosome dimers frequently formed in the process.

    PubMed

    Johnston, Calum; Mortier-Barrière, Isabelle; Granadel, Chantal; Polard, Patrice; Martin, Bernard; Claverys, Jean-Pierre

    2015-01-01

    Homologous recombination (HR) is required for both genome maintenance and generation of diversity in eukaryotes and prokaryotes. This process initiates from single-stranded (ss) DNA and is driven by a universal recombinase, which promotes strand exchange between homologous sequences. The bacterial recombinase, RecA, is loaded onto ssDNA by recombinase loaders, RecBCD and RecFOR for genome maintenance. DprA was recently proposed as a third loader dedicated to genetic transformation. Here we assessed the role of RecFOR in transformation of the human pathogen Streptococcus pneumoniae. We firstly established that RecFOR proteins are not required for plasmid transformation, strongly suggesting that DprA ensures annealing of plasmid single-strands internalized in the process. We then observed no reduction in chromosomal transformation using a PCR fragment as donor, contrasting with the 10,000-fold drop in dprA- cells and demonstrating that RecFOR play no role in transformation. However, a ∼1.45-fold drop in transformation was observed with total chromosomal DNA in recFOR mutants. To account for this limited deficit, we hypothesized that transformation with chromosomal DNA stimulated unexpectedly high frequency (>30% of cells) formation of chromosome dimers as an intermediate in the generation of tandem duplications, and that RecFOR were crucial for dimer resolution. We validated this hypothesis, showing that the site-specific recombinase XerS was also crucial for dimer resolution. An even higher frequency of dimer formation (>80% of cells) was promoted by interspecies transformation with Streptococcus mitis chromosomal DNA, which contains numerous inversions compared to pneumococcal chromosome, each potentially promoting dimerization. In the absence of RecFOR and XerS, dimers persist, as confirmed by DAPI staining, and can limit the efficiency of transformation, since resulting in loss of transformant chromosome. These findings strengthen the view that different HR

  2. RecFOR Is Not Required for Pneumococcal Transformation but Together with XerS for Resolution of Chromosome Dimers Frequently Formed in the Process

    PubMed Central

    Johnston, Calum; Mortier-Barrière, Isabelle; Granadel, Chantal; Polard, Patrice; Martin, Bernard; Claverys, Jean-Pierre

    2015-01-01

    Homologous recombination (HR) is required for both genome maintenance and generation of diversity in eukaryotes and prokaryotes. This process initiates from single-stranded (ss) DNA and is driven by a universal recombinase, which promotes strand exchange between homologous sequences. The bacterial recombinase, RecA, is loaded onto ssDNA by recombinase loaders, RecBCD and RecFOR for genome maintenance. DprA was recently proposed as a third loader dedicated to genetic transformation. Here we assessed the role of RecFOR in transformation of the human pathogen Streptococcus pneumoniae. We firstly established that RecFOR proteins are not required for plasmid transformation, strongly suggesting that DprA ensures annealing of plasmid single-strands internalized in the process. We then observed no reduction in chromosomal transformation using a PCR fragment as donor, contrasting with the 10,000-fold drop in dprA - cells and demonstrating that RecFOR play no role in transformation. However, a ∼1.45-fold drop in transformation was observed with total chromosomal DNA in recFOR mutants. To account for this limited deficit, we hypothesized that transformation with chromosomal DNA stimulated unexpectedly high frequency (>30% of cells) formation of chromosome dimers as an intermediate in the generation of tandem duplications, and that RecFOR were crucial for dimer resolution. We validated this hypothesis, showing that the site-specific recombinase XerS was also crucial for dimer resolution. An even higher frequency of dimer formation (>80% of cells) was promoted by interspecies transformation with Streptococcus mitis chromosomal DNA, which contains numerous inversions compared to pneumococcal chromosome, each potentially promoting dimerization. In the absence of RecFOR and XerS, dimers persist, as confirmed by DAPI staining, and can limit the efficiency of transformation, since resulting in loss of transformant chromosome. These findings strengthen the view that different HR

  3. Functional Significance of Serotonin Receptor Dimerization

    PubMed Central

    Herrick-Davis, Katharine

    2013-01-01

    The original model of G protein activation by a single G-protein-coupled receptor (GPCR) is giving way to a new model wherein two protomers of a GPCR dimer interact with a single G protein. This article will review the evidence suggesting that 5-HT receptors form dimers/oligomers and will compare the findings with results obtained from studies with other biogenic amine receptors. Topics to be covered include the origin or biogenesis of dimer formation, potential dimer interface(s), and oligomer size (dimer versus tetramer or higher order). The functional significance will be discussed in terms of G-protein activation following ligand binding to one or two protomers in a dimeric structure, the formation of heterodimers and the development of bivalent ligands. PMID:23811735

  4. Structural insights into the IgE mediated responses induced by the allergens Hev b 8 and Zea m 12 in their dimeric forms

    PubMed Central

    Mares-Mejía, Israel; Martínez-Caballero, Siseth; Garay-Canales, Claudia; Cano-Sánchez, Patricia; Torres-Larios, Alfredo; Lara-González, Samuel; Ortega, Enrique; Rodríguez-Romero, Adela

    2016-01-01

    Oligomerization of allergens plays an important role in IgE-mediated reactions, as effective crosslinking of IgE- FcεRI complexes on the cell membrane is dependent on the number of exposed B-cell epitopes in a single allergen molecule or on the occurrence of identical epitopes in a symmetrical arrangement. Few studies have attempted to experimentally demonstrate the connection between allergen dimerization and the ability to trigger allergic reactions. Here we studied plant allergenic profilins rHev b 8 (rubber tree) and rZea m 12 (maize) because they represent an important example of cross-reactivity in the latex-pollen-food syndrome. Both allergens in their monomeric and dimeric states were isolated and characterized by exclusion chromatography and mass spectrometry and were used in immunological in vitro experiments. Their crystal structures were solved, and for Hev b 8 a disulfide-linked homodimer was found. Comparing the structures we established that the longest loop is relevant for recognition by IgE antibodies, whereas the conserved regions are important for cross-reactivity. We produced a novel monoclonal murine IgE (mAb 2F5), specific for rHev b 8, which was useful to provide evidence that profilin dimerization considerably increases the IgE-mediated degranulation in rat basophilic leukemia cells. PMID:27586352

  5. Structural insights into the IgE mediated responses induced by the allergens Hev b 8 and Zea m 12 in their dimeric forms.

    PubMed

    Mares-Mejía, Israel; Martínez-Caballero, Siseth; Garay-Canales, Claudia; Cano-Sánchez, Patricia; Torres-Larios, Alfredo; Lara-González, Samuel; Ortega, Enrique; Rodríguez-Romero, Adela

    2016-01-01

    Oligomerization of allergens plays an important role in IgE-mediated reactions, as effective crosslinking of IgE- FcεRI complexes on the cell membrane is dependent on the number of exposed B-cell epitopes in a single allergen molecule or on the occurrence of identical epitopes in a symmetrical arrangement. Few studies have attempted to experimentally demonstrate the connection between allergen dimerization and the ability to trigger allergic reactions. Here we studied plant allergenic profilins rHev b 8 (rubber tree) and rZea m 12 (maize) because they represent an important example of cross-reactivity in the latex-pollen-food syndrome. Both allergens in their monomeric and dimeric states were isolated and characterized by exclusion chromatography and mass spectrometry and were used in immunological in vitro experiments. Their crystal structures were solved, and for Hev b 8 a disulfide-linked homodimer was found. Comparing the structures we established that the longest loop is relevant for recognition by IgE antibodies, whereas the conserved regions are important for cross-reactivity. We produced a novel monoclonal murine IgE (mAb 2F5), specific for rHev b 8, which was useful to provide evidence that profilin dimerization considerably increases the IgE-mediated degranulation in rat basophilic leukemia cells. PMID:27586352

  6. Structural insights into the IgE mediated responses induced by the allergens Hev b 8 and Zea m 12 in their dimeric forms.

    PubMed

    Mares-Mejía, Israel; Martínez-Caballero, Siseth; Garay-Canales, Claudia; Cano-Sánchez, Patricia; Torres-Larios, Alfredo; Lara-González, Samuel; Ortega, Enrique; Rodríguez-Romero, Adela

    2016-09-02

    Oligomerization of allergens plays an important role in IgE-mediated reactions, as effective crosslinking of IgE- FcεRI complexes on the cell membrane is dependent on the number of exposed B-cell epitopes in a single allergen molecule or on the occurrence of identical epitopes in a symmetrical arrangement. Few studies have attempted to experimentally demonstrate the connection between allergen dimerization and the ability to trigger allergic reactions. Here we studied plant allergenic profilins rHev b 8 (rubber tree) and rZea m 12 (maize) because they represent an important example of cross-reactivity in the latex-pollen-food syndrome. Both allergens in their monomeric and dimeric states were isolated and characterized by exclusion chromatography and mass spectrometry and were used in immunological in vitro experiments. Their crystal structures were solved, and for Hev b 8 a disulfide-linked homodimer was found. Comparing the structures we established that the longest loop is relevant for recognition by IgE antibodies, whereas the conserved regions are important for cross-reactivity. We produced a novel monoclonal murine IgE (mAb 2F5), specific for rHev b 8, which was useful to provide evidence that profilin dimerization considerably increases the IgE-mediated degranulation in rat basophilic leukemia cells.

  7. High ethanol and acetaldehyde impair spatial memory in mouse models: opposite effects of aldehyde dehydrogenase 2 and apolipoprotein E on memory.

    PubMed

    Jamal, Mostofa; Ameno, Kiyoshi; Miki, Takanori; Tanaka, Naoko; Ono, Junichiro; Shirakami, Gotaro; Sultana, Ruby; Yu, Nakamura; Kinoshita, Hiroshi

    2012-05-01

    Aldehyde dehydrogenase 2 deficiency may directly contribute to excess acetaldehyde (AcH) accumulation after ethanol (EtOH) drinking and AcH mediates some of the behavioral effects of EtOH. Apolipoprotein E has been suggested to be involved in the alteration of attention and memory. We have chosen Aldh2-knockout (Aldh2-KO), ApoE-KO, and their wild-type (WT) control mice to examine the effects of EtOH and AcH on spatial memory and to compare the possible relationship between genetic deficiency and memory using two behavioral assessments. Mice were trained for 4 days, with EtOH (0.5, 1.0, 2.0 g/kg) being given intraperitoneally on day 4. A probe trial was given on day 5 in the non-EtOH state in the Morris water maze (MWM). The results showed that 2.0 g/kg EtOH increased errors, indicating memory impairment on the eight-arm radial maze (RAM) for all the mice studied. One gram per kilogram EtOH impaired the performance of Aldh2-KO and ApoE-KO mice, but not WT mice. We found similar effects of EtOH on the MWM performance, with 2.0 g/kg EtOH increasing the latencies. One gram per kilogram EtOH increased the latencies of Aldh2-KO and WT mice, but not ApoE-KO mice. The 2.0 g/kg EtOH-induced memory impairment in Aldh2-KO mice was greater, suggesting an AcH effect. Furthermore, time spent on the probe trial was shorter in mice that had previously received 2.0 g/kg EtOH. ApoE-KO mice learned more slowly, while Aldh2-KO mice learned more quickly. Both the RAM and MWM results suggest that high EtOH and AcH impair spatial memory in mice, while lower doses do not have consistent memory effects. In addition, we conclude that genetic differences might underlie some of EtOH's effects on memory.

  8. Apolipoprotein E enhances hepatic lipase-mediated hydrolysis of reconstituted high-density lipoprotein phospholipid and triacylglycerol in an isoform-dependent manner.

    PubMed

    Hime, Neil J; Drew, Kate J; Hahn, Chris; Barter, Philip J; Rye, Kerry-Anne

    2004-09-28

    This study compares the kinetics of hepatic lipase (HL)-mediated phospholipid and triacylglycerol hydrolysis in spherical, reconstituted high-density lipoproteins (rHDL) that contain either apolipoprotein E2 (apoE2), apoE3, apoE4, or apoA-I as the sole apolipoprotein. HL-mediated phospholipid hydrolysis was assessed by incubating various concentrations of rHDL that contained only cholesteryl esters (CE) in their core, (E2/CE)rHDL, (E3/CE)rHDL, (E4/CE)rHDL, and (A-I/CE)rHDL, with a constant amount of HL. The rate of phospholipid hydrolysis was determined as the formation of nonesterified fatty acid mass. HL-mediated triacylglycerol hydrolysis was assessed in rHDL containing CE, unlabeled triacylglycerol, and [(3)H]triacylglycerol in their core, (E2/TG)rHDL, (E3/TG)rHDL, (E4/TG)rHDL, and (A-I/TG)rHDL. Triacylglycerol hydrolysis was determined as the ratio of (3)H-labeled hydrolysis products to (3)H-labeled unhydrolyzed triacylglycerol. The rates of phospholipid hydrolysis in the (E2/CE)rHDL, (E3/CE)rHDL, and (E4/CE)rHDL were significantly greater than that in the (A-I/CE)rHDL. The rates of triacylglycerol hydrolysis were also greater in the (E2/TG)rHDL, (E3/TG)rHDL, and (E4/TG)rHDL compared to the (A-I/TG)rHDL, although to a lesser degree than observed with phospholipid hydrolysis. Furthermore, the rates of both phospholipid and triacylglycerol hydrolyses were greater in the (E2)rHDL than in either the (E3)rHDL or the (E4)rHDL. These results show that apoE increases the rate of HL-mediated phospholipid and triacylglycerol hydrolysis in rHDL and that this influence is isoform dependent.

  9. Age, gender, and cancer but not neurodegenerative and cardiovascular diseases strongly modulate systemic effect of the Apolipoprotein E4 allele on lifespan.

    PubMed

    Kulminski, Alexander M; Arbeev, Konstantin G; Culminskaya, Irina; Arbeeva, Liubov; Ukraintseva, Svetlana V; Stallard, Eric; Christensen, Kaare; Schupf, Nicole; Province, Michael A; Yashin, Anatoli I

    2014-01-01

    Enduring interest in the Apolipoprotein E (ApoE) polymorphism is ensured by its evolutionary-driven uniqueness in humans and its prominent role in geriatrics and gerontology. We use large samples of longitudinally followed populations from the Framingham Heart Study (FHS) original and offspring cohorts and the Long Life Family Study (LLFS) to investigate gender-specific effects of the ApoE4 allele on human survival in a wide range of ages from midlife to extreme old ages, and the sensitivity of these effects to cardiovascular disease (CVD), cancer, and neurodegenerative disorders (ND). The analyses show that women's lifespan is more sensitive to the e4 allele than men's in all these populations. A highly significant adverse effect of the e4 allele is limited to women with moderate lifespan of about 70 to 95 years in two FHS cohorts and the LLFS with relative risk of death RR = 1.48 (p = 3.6 × 10(-6)) in the FHS cohorts. Major human diseases including CVD, ND, and cancer, whose risks can be sensitive to the e4 allele, do not mediate the association of this allele with lifespan in large FHS samples. Non-skin cancer non-additively increases mortality of the FHS women with moderate lifespans increasing the risks of death of the e4 carriers with cancer two-fold compared to the non-e4 carriers, i.e., RR = 2.07 (p = 5.0 × 10(-7)). The results suggest a pivotal role of non-sex-specific cancer as a nonlinear modulator of survival in this sample that increases the risk of death of the ApoE4 carriers by 150% (p = 5.3 × 10(-8)) compared to the non-carriers. This risk explains the 4.2 year shorter life expectancy of the e4 carriers compared to the non-carriers in this sample. The analyses suggest the existence of age- and gender-sensitive systemic mechanisms linking the e4 allele to lifespan which can non-additively interfere with cancer-related mechanisms.

  10. MicroRNA-27 Prevents Atherosclerosis by Suppressing Lipoprotein Lipase-Induced Lipid Accumulation and Inflammatory Response in Apolipoprotein E Knockout Mice

    PubMed Central

    Cheng, Hai-Peng; Gong, Duo; Lv, Yun-Cheng; Yao, Feng; He, Ping-Ping; Ouyang, Xin-Ping; Lan, Gang; Liu, Dan; Zhao, Zhen-Wang; Tan, Yu-Lin; Zheng, Xi-Long; Yin, Wei-Dong; Tang, Chao-Ke

    2016-01-01

    Atherosclerotic lesions are lipometabolic disorder characterized by chronic progressive inflammation in arterial walls. Previous studies have shown that macrophage-derived lipoprotein lipase (LPL) might be a key factor that promotes atherosclerosis by accelerating lipid accumulation and proinflammatory cytokine secretion. Increasing evidence indicates that microRNA-27 (miR-27) has beneficial effects on lipid metabolism and inflammatory response. However, it has not been fully understood whether miR-27 affects the expression of LPL and subsequent development of atherosclerosis in apolipoprotein E knockout (apoE KO) mice. To address these questions and its potential mechanisms, oxidized low-density lipoprotein (ox-LDL)-treated THP-1 macrophages were transfected with the miR-27 mimics/inhibitors and apoE KO mice fed high-fat diet were given a tail vein injection with miR-27 agomir/antagomir, followed by exploring the potential roles of miR-27. MiR-27 agomir significantly down-regulated LPL expression in aorta and peritoneal macrophages by western blot and real-time PCR analyses. We performed LPL activity assay in the culture media and found that miR-27 reduced LPL activity. ELISA showed that miR-27 reduced inflammatory response as analyzed in vitro and in vivo experiments. Our results showed that miR-27 had an inhibitory effect on the levels of lipid both in plasma and in peritoneal macrophages of apoE KO mice as examined by HPLC. Consistently, miR-27 suppressed the expression of scavenger receptors associated with lipid uptake in ox-LDL-treated THP-1 macrophages. In addition, transfection with LPL siRNA inhibited the miR-27 inhibitor-induced lipid accumulation and proinflammatory cytokines secretion in ox-LDL-treated THP-1 macrophages. Finally, systemic treatment revealed that miR-27 decreased aortic plaque size and lipid content in apoE KO mice. The present results provide evidence that a novel antiatherogenic role of miR-27 was closely related to reducing lipid

  11. The crystal structures of the calcium-bound con-G and con-T[K7gamma] dimeric peptides demonstrate a metal-dependent helix-forming motif.

    PubMed

    Cnudde, Sara E; Prorok, Mary; Dai, Qiuyun; Castellino, Francis J; Geiger, James H

    2007-02-14

    Short peptides that have the ability to form stable alpha-helices in solution are rare, and a number of strategies have been used to produce them, including the use of metal chelation to stabilize folding of the backbone. However, no example exists of a structurally well-defined helix stabilized exclusively through metal ion chelation. Conantokins (con)-G and -T are short peptides that are potent antagonists of N-methyl-D-aspartate receptor channels. While con-G exhibits no helicity alone, it undergoes a structural transition to a helical conformation in the presence of a variety of multivalent cations, especially Mg2+ and Ca2+. This complexation also results in antiparallel dimerization of two peptide helices in the presence of Ca2+, but not Mg2+. A con-T variant, con-T[K7gamma], displays very similar behavior. We have solved the crystal structures of both Ca2+/con-G and Ca2+/con-T [K7gamma] at atomic resolution. These structures clearly show the nature of the metal-dependent dimerization and helix formation and surprisingly also show that the con-G dimer interface is completely different from the con-T[K7gamma] interface, even though the metal chelation is similar in the two peptides. This represents a new paradigm in helix stabilization completely independent of the hydrophobic effect, which we define as the "metallo-zipper."

  12. D-dimer test

    MedlinePlus

    D-dimer tests are used to check for blood clotting problems. Blood clots can cause health problems, such ... that you probably do not have problems with blood clotting. If you are getting the D-dimer test ...

  13. Mechanically Stabilized Tetrathiafulvalene Radical Dimers

    SciTech Connect

    Coskun, Ali; Spruell, Jason M.; Barin, Gokhan; Fahrenbach, Albert C.; Forgan, Ross S.; Colvin, Michael T.; Carmieli, Raanan; Benitez, Diego; Tkatchouk, Ekaterina; Friedman, Douglas C.; Sarjeant, Amy A.; Wasielewski, Michael R.; Goddard, William A.; Stoddart, J. Fraser

    2011-01-01

    Two donor-acceptor [3]catenanes—composed of a tetracationic molecular square, cyclobis(paraquat-4,4'-biphenylene), as the π-electron deficient ring and either two tetrathiafulvalene (TTF) and 1,5-dioxynaphthalene (DNP) containing macrocycles or two TTF-butadiyne-containing macrocycles as the π-electron rich components—have been investigated in order to study their ability to form TTF radical dimers. It has been proven that the mechanically interlocked nature of the [3]catenanes facilitates the formation of the TTF radical dimers under redox control, allowing an investigation to be performed on these intermolecular interactions in a so-called “molecular flask” under ambient conditions in considerable detail. In addition, it has also been shown that the stability of the TTF radical-cation dimers can be tuned by varying the secondary binding motifs in the [3]catenanes. By replacing the DNP station with a butadiyne group, the distribution of the TTF radical-cation dimer can be changed from 60% to 100%. These findings have been established by several techniques including cyclic voltammetry, spectroelectrochemistry and UV-vis-NIR and EPR spectroscopies, as well as with X-ray diffraction analysis which has provided a range of solid-state crystal structures. The experimental data are also supported by high-level DFT calculations. The results contribute significantly to our fundamental understanding of the interactions within the TTF radical dimers.

  14. Ligand regulation of a constitutively dimeric EGF receptor

    NASA Astrophysics Data System (ADS)

    Freed, Daniel M.; Alvarado, Diego; Lemmon, Mark A.

    2015-06-01

    Ligand-induced receptor dimerization has traditionally been viewed as the key event in transmembrane signalling by epidermal growth factor receptors (EGFRs). Here we show that the Caenorhabditis elegans EGFR orthologue LET-23 is constitutively dimeric, yet responds to its ligand LIN-3 without changing oligomerization state. SAXS and mutational analyses further reveal that the preformed dimer of the LET-23 extracellular region is mediated by its domain II dimerization arm and resembles other EGFR extracellular dimers seen in structural studies. Binding of LIN-3 induces only minor structural rearrangements in the LET-23 dimer to promote signalling. Our results therefore argue that EGFR can be regulated by allosteric changes within an existing receptor dimer--resembling signalling by insulin receptor family members, which share similar extracellular domain compositions but form covalent dimers.

  15. Influence of Aqueous-Salt Conditions on the Structure and Dynamics of the Monomeric and Novel Dimeric forms of the Alzheimer s ABeta21-30 protein fragment

    NASA Astrophysics Data System (ADS)

    Smith, Micholas Dean

    The behavior of the Alzheimer's related peptide Abeta is the subject of much study. In typical computational studies the environment local to the peptide is assumed to be pure water; however, in vivo the peptide is found in the extracellular space near the plasma membrane which is rich in ionic species. In this thesis, the hypothesis that the presence of group I/IIA salts will result in increased sampling of disordered structures as well as modify the dynamics of meta-stable structural motifs in the small folding nucleus of the Abeta peptide (Abeta21-30) is examined under a variety of ionic environments and was shown that of the tested salts, CaCl2 (and MgCl2, to a much lesser degree) did increase the propensity for disordered states; while, the group IA salts, KCl and NaCl, had little effect on the secondary structure of the peptide. Further, study of three familial mutations of this peptide region is also performed under aqueous salt-environments to elucidate further mechanistic details of how aqueous salts modify the region's behavior. Finally, as experimental results have highlighted that aggregation rates of the full-length peptide are modified by the presence of CaCl2, this work examines novel dimers states of Abeta21-30 and their stabilities when exposed to CaCl2.

  16. Ammine(2,2′-bipyridine-κ2 N,N′)silver(I) nitrate: a dimer formed by π–π stacking and ligand-unsupported Ag⋯Ag inter­actions

    PubMed Central

    Sun, Di; Zhang, Na; Luo, Geng-Geng; Huang, Rong-Bin; Zheng, Lan-Sun

    2010-01-01

    Reaction of AgNO3 and 2,2′-bipyridine (bipy) under ultrasonic treatment gave the title compound, [Ag(C10H8N2)(NH3)]NO3. The crystal structure consists of dimers formed by two symmetry-related AgI–bipy monomers connected through intra-dimer π–π stacking and ligand-unsupported Ag⋯Ag inter­actions. A crystallographic C2 axis passes through the mid-point of and is perpendicular to the Ag⋯Agi(−x + 1, y, −z + ) axis. In addition, each AgI cation is coordinated by one chelating bipy ligand and one ammine ligand, giving a trigonal coordination environment capped by the symmetry-equivalent Ag atom. Mol­ecules are assembled by Ag⋯Ag, π–π, hydrogen-bond (N—H⋯O and C—H⋯O) and weak Ag⋯π inter­actions into a three-dimensional framework. Comparing the products synthesized under different mechanical treatments, we found that reaction conditions have a significant influence on the resulting structures. The luminescence properties of the title compound are also discussed. PMID:20203399

  17. Influence of socio-demographic features and apolipoprotein E epsilon 4 expression on the prevalence of dementia and cognitive impairment in a population of 70-74-year olds: the InveCe.Ab study.

    PubMed

    Guaita, Antonio; Vaccaro, Roberta; Davin, Annalisa; Colombo, Mauro; Vitali, Silvia Francesca; Polito, Letizia; Abbondanza, Simona; Valle, Eleonora; Forloni, Gianluigi; Ferretti, Virginia Valeria; Villani, Simona

    2015-01-01

    The age-specific prevalence rates of dementia vary widely. Studies focusing on specific age groups are needed to provide reliable estimates for healthcare providers and policy makers. We estimated the prevalence of dementia, dementia subtypes and cognitive impairment in "InveCe.Ab" (ClinicalTrials.gov, NCT01345110), a single-step multidimensional population-based study of 70-74-year olds living in Abbiategrasso (Milan, Italy). We also looked for associations with socio-demographic factors and the presence of the apolipoprotein E-ɛ4 allele. The overall dementia prevalence was 3% (95%CI: 2.1-4.1%) [Alzheimer's disease (AD): 1.2% (95%CI 0.6-1.9%); vascular dementia (VD): 1.4% (95%CI: 0.8-2.2%)]. Being single was found to be a risk factor for vascular dementia; subjects born in southern Italy were shown to be at greater risk both of overall dementia and of vascular dementia. The prevalence of cognitive impairment, with or without subjective cognitive complaints (cognitive impairment, no dementia, CIND) was 7.8% (95%CI: 6.4-9.4%). As regards the CIND subgroups, the prevalence of subjects with subjective cognitive complaints (mild cognitive impairment, MCI) was 5.0% (95%CI 3.9-6.3%), while the prevalence of those without MCI (CIND-other) was 2.8% (95%CI: 1.9-3.8). The males had a higher risk of MCI and CIND-other; the older subjects were more likely to have MCI, and those born in north-eastern Italy to have CIND-other. The prevalence of AD was higher among the apolipoprotein E-ɛ4 carriers. Our data highlight the importance of dementia and cognitive impairment in the transitional period from adulthood to old age, and reveal the presence of different associations with socio-demographic and genetic factors.

  18. Dimeric Cinchona alkaloids.

    PubMed

    Boratyński, Przemysław J

    2015-05-01

    Nature is full of dimeric alkaloids of various types from many plant families, some of them with interesting biological properties. However, dimeric Cinchona alkaloids were not isolated from any species but were products of designed partial chemical synthesis. Although the Cinchona bark is amongst the sources of oldest efficient medicines, the synthetic dimers found most use in the field of asymmetric synthesis. Prominent examples include the Sharpless dihydroxylation and aminohydroxylation ligands, and dimeric phase transfer catalysts. In this article the syntheses of Cinchona alkaloid dimers and oligomers are reviewed, and their structure and applications are outlined. Various synthetic routes exploit reactivity of the alkaloids at the central 9-hydroxyl group, quinuclidine, and quinoline rings, as well as 3-vinyl group. This availability of reactive sites, in combination with a plethora of linker molecules, contributes to the diversity of the products obtained.

  19. 2-Amino-3,5-dichlorobenzonitrile: DFT calculations in the monomer and dimer forms, FT-IR and FT-Raman spectra, molecular geometry, atomic charges and thermodynamical parameters.

    PubMed

    Rastogi, V K; Alcolea Palafox, M; Tomar, Rashmi; Singh, Upama

    2013-06-01

    The experimental IR and Raman spectra of 2-amino-3,5-dichlorobenzonitrile molecule were recorded, and the results compared with theoretical values. Molecular geometry, vibrational wavenumbers and thermodynamic parameters were calculated using MP2 and DFT quantum chemical methods. With the help of specific scaling procedures for the computed wavenumbers, the experimentally observed FTIR and FT-Raman bands were analyzed and assigned to different normal modes of vibrations of the molecule. Simulations in the dimer form were carried out to improve the assignment of the bands in the solid state experimental spectra. The error obtained was in general very low. Using PED's were determined the contributions of the different modes to each wavenumber. Several general conclusions were also deduced.

  20. Dimer monomer transition and dimer re-formation play important role for ATM cellular function during DNA repair

    SciTech Connect

    Du, Fengxia; Zhang, Minjie; Li, Xiaohua; Yang, Caiyun; Meng, Hao; Wang, Dong; Chang, Shuang; Xu, Ye; Price, Brendan; Sun, Yingli

    2014-10-03

    Highlights: • ATM phosphorylates the opposite strand of the dimer in response to DNA damage. • The PETPVFRLT box of ATM plays a key role in its dimer dissociation in DNA repair. • The dephosphorylation of ATM is critical for dimer re-formation after DNA repair. - Abstract: The ATM protein kinase, is a serine/threonine protein kinase that is recruited and activated by DNA double-strand breaks, mediates responses to ionizing radiation in mammalian cells. Here we show that ATM is held inactive in unirradiated cells as a dimer and phosphorylates the opposite strand of the dimer in response to DNA damage. Cellular irradiation induces rapid intermolecular autophosphorylation of serine 1981 that causes dimer dissociation and initiates cellular ATM kinase activity. ATM cannot phosphorylate the substrates when it could not undergo dimer monomer transition. After DNA repair, the active monomer will undergo dephosphorylation to form dimer again and dephosphorylation is critical for dimer re-formation. Our work reveals novel function of ATM dimer monomer transition and explains why ATM dimer monomer transition plays such important role for ATM cellular activity during DNA repair.

  1. Dimerization of lipocalin allergens

    PubMed Central

    Niemi, Merja H.; Rytkönen-Nissinen, Marja; Miettinen, Ilja; Jänis, Janne; Virtanen, Tuomas; Rouvinen, Juha

    2015-01-01

    Lipocalins are one of the most important groups of inhalant animal allergens. The analysis of structural features of these proteins is important to get insights into their allergenicity. We have determined two different dimeric crystal structures for bovine dander lipocalin Bos d 2, which was earlier described as a monomeric allergen. The crystal structure analysis of all other determined lipocalin allergens also revealed oligomeric structures which broadly utilize inherent structural features of the β-sheet in dimer formation. According to the moderate size of monomer-monomer interfaces, most of these dimers would be transient in solution. Native mass spectrometry was employed to characterize quantitatively transient dimerization of two lipocalin allergens, Bos d 2 and Bos d 5, in solution. PMID:26346541

  2. RING DOMAIN DIMERIZATION IS ESSENTIAL FOR RNF4 FUNCTION

    PubMed Central

    Liew, Chu Wai; Sun, Huaiyu; Hunter, Tony; Day, Catherine L.

    2011-01-01

    SYNOPSIS RNF4 family ubiquitin ligases are RING E3 ligases that regulate the homeostasis of SUMOylated proteins by promoting their ubiquitylation. Here we report that the RING domain of RNF4 forms a stable dimer, and that dimerization is required for ubiquitin transfer. Our data suggests that the stability of the E2~ubiquitin thioester bond is regulated by RING domain dimerization. PMID:20681948

  3. Oligomerization of deoxynucleoside-bisphosphate dimers: template and linkage specificity

    NASA Technical Reports Server (NTRS)

    Visscher, J.; van der Woerd, R.; Bakker, C. G.; Schwartz, A. W.; Orgel, L. E. (Principal Investigator)

    1989-01-01

    Evidence is presented that a poly(U) template selectively favors the oligomerization of the activated, 3'-5' pyrophosphate-linked dimer pdAppdAp, in comparison with the 3'-3' and 5'-5' linked dimers. In the absence of poly(U), the 5'-5' linked dimer is the most reactive, and chains are formed which are more than 60 monomer units in length.

  4. Peptides Interfering 3A Protein Dimerization Decrease FMDV Multiplication

    PubMed Central

    de la Torre, Beatriz G.; Valle, Javier; Andreu, David; Sobrino, Francisco

    2015-01-01

    Nonstructural protein 3A is involved in relevant functions in foot-and-mouth disease virus (FMDV) replication. FMDV 3A can form homodimers and preservation of the two hydrophobic α-helices (α1 and α2) that stabilize the dimer interface is essential for virus replication. In this work, small peptides mimicking residues involved in the dimer interface were used to interfere with dimerization and thus gain insight on its biological function. The dimer interface peptides α1, α2 and that spanning the two hydrophobic α-helices, α12, impaired in vitro dimer formation of a peptide containing the two α-helices, this effect being higher with peptide α12. To assess the effect of dimer inhibition in cultured cells, the interfering peptides were N-terminally fused to a heptaarginine (R7) sequence to favor their intracellular translocation. Thus, when fused to R7, interference peptides (100 μM) were able to inhibit dimerization of transiently expressed 3A, the higher inhibitions being found with peptides α1 and α12. The 3A dimerization impairment exerted by the peptides correlated with significant, specific reductions in the viral yield recovered from peptide-treated FMDV infected cells. In this case, α2 was the only peptide producing significant reductions at concentrations lower than 100 μM. Thus, dimer interface peptides constitute a tool to understand the structure-function relationship of this viral protein and point to 3A dimerization as a potential antiviral target. PMID:26505190

  5. Superbackscattering nanoparticle dimers.

    PubMed

    Liberal, Iñigo; Ederra, Iñigo; Gonzalo, Ramón; Ziolkowski, Richard W

    2015-07-10

    The theory and design of superbackscattering nanoparticle dimers are presented. We analytically derive the optimal configurations and the upper bound of their backscattering cross-sections. In particular, it is demonstrated that electrically small nanoparticle dimers can enhance the backscattering by a factor of 6.25 with respect to single dipolar particles. We demonstrate that optimal designs approaching this theoretical limit can be found by using a simple circuit model. The study of practical implementations based on plasmonic and high-permittivity particles has been also addressed. Moreover, the numerical examples reveal that the dimers can attain close to a fourfold enhancement of the single nanoparticle response even in the presence of high losses.

  6. Superbackscattering nanoparticle dimers

    NASA Astrophysics Data System (ADS)

    Liberal, Iñigo; Ederra, Iñigo; Gonzalo, Ramón; Ziolkowski, Richard W.

    2015-07-01

    The theory and design of superbackscattering nanoparticle dimers are presented. We analytically derive the optimal configurations and the upper bound of their backscattering cross-sections. In particular, it is demonstrated that electrically small nanoparticle dimers can enhance the backscattering by a factor of 6.25 with respect to single dipolar particles. We demonstrate that optimal designs approaching this theoretical limit can be found by using a simple circuit model. The study of practical implementations based on plasmonic and high-permittivity particles has been also addressed. Moreover, the numerical examples reveal that the dimers can attain close to a fourfold enhancement of the single nanoparticle response even in the presence of high losses.

  7. Mutation of Non-Essential Cysteines Shows that NF-κB Essential Modulator (NEMO) Forms a Constitutive Noncovalent Dimer that Binds IκB Kinase-β (IKKβ) with High Affinity

    PubMed Central

    Cote, Shaun M.; Gilmore, Thomas D.; Shaffer, Robert; Weber, Urs; Bollam, Rishitha; Golden, Mary S.; Glover, Kimberley; Herscovitch, Melanie; Ennis, Thomas; Allen, Karen N.; Whitty, Adrian

    2014-01-01

    NEMO (NF-κB essential modulator) associates with the catalytic subunits IKKα and IKKβ to form the IκB kinase (IKK) complex, and is a key regulator of NF-κB pathway signaling. Biochemical and structural characterization of NEMO has been challenging, however, leading to conflicting data on basic biochemical properties such as the oligomeric state of active NEMO and its binding affinity for IKKβ. We show that up to seven of NEMO’s 11 cysteine residues can be mutated to generate recombinant full-length NEMO that is highly soluble and active. Using a fluorescence anisotropy binding assay we show that full-length NEMO binds a 44-mer peptide encompassing residues 701-745 of IKKβ with KD = 2.2 ± 0.8 nM. The IKKβ binding affinities of mutants with five and seven Cys-to-Ala substitutions are indistinguishable from that of wild-type NEMO. Moreover, when expressed in NEMO −/− fibroblasts, the 5xAla and 7xAla NEMO mutants can interact with cellular IKKβ and restore NF-κB signaling to provide protection against TNFα-induced cell death. Treatment of the NEMO-reconstituted cells with H2O2 led to formation of covalent dimers for wild-type NEMO and the 5xAla mutant, but not for the 7xAla mutant, confirming that Cys54 and/or Cys347 can mediate inter-chain disulfide bonding. However, the IKKβ binding affinity of NEMO is unaffected by the presence or absence of inter-chain disulfide bonding at Cys54 – which lies within the IKKβ binding domain of NEMO – or at Cys347, indicating that NEMO exists as a noncovalent dimer independent of the redox state of its cysteines. This conclusion was corroborated by the observation that the secondary structure content of NEMO and its thermal stability were independent of the presence or absence of inter-chain disulfide bonds. PMID:24266532

  8. Involvement of NADPH oxidase in up-regulation of plasminogen activator inhibitor-1 and heat shock factor-1 in mouse embryo fibroblasts induced by oxidized LDL and in apolipoprotein E-deficient mice.

    PubMed

    Zhao, Ruozhi; Moghadasian, Mohammed H; Shen, Garry X

    2011-09-01

    The present study demonstrated that oxidized LDL (oLDL) increased the generation of superoxide and hydrogen peroxide (H(2)O(2)), the abundances of NADPH oxidase (NOX)4, NOX2, p22-phox and lectin-like oLDL receptor-1 (LOX-1) in wild-type or heat shock factor-1 (HSF1)-deficient mouse embryo fibroblasts (MEF). LOX-1 antibody inhibited LDL or oLDL-induced expression of NOX components in MEF. Abundance of HSF1 or plasminogen activator inhibitor-1 (PAI-1) was increased by oLDL in wild-type, but not in HSF1-deficient MEF. Diphenyleneiodonium or siRNA for NOX or p22-phox inhibited oLDL-induced increases of HSF1, PAI-1 and H(2)O(2) in MEF. Increased NOX4, NOX2, LOX1, HSF1 and PAI-1 were detected in aortae and hearts of apolipoprotein E-knockout (apoE-KO) mice compared to controls, which were associated with increased serum cholesterol or plasma PAI-1. The results suggest that NOX is required for oLDL-induced HSF1 or PAI-1 expression in MEF, which was supported by the up-regulation of NOX, LOX-1, HSF1 and PAI-1 in apoE-KO mice.

  9. Quantum Dimer Model: Phase Diagrams

    NASA Astrophysics Data System (ADS)

    Goldstein, Garry; Chamon, Claudio; Castelnovo, Claudio

    We present new theoretical analysis of the Quantum Dimer Model. We study dimer models on square, cubic and triangular lattices and we reproduce their phase diagrams (which were previously known only numerically). We show that there are several types of dimer liquids and solids. We present preliminary analysis of several other models including doped dimers and planar spin ice, and some results on the Kagome and hexagonal lattices.

  10. The ability of apolipoprotein E fragments to promote intraneuronal accumulation of amyloid beta peptide 42 is both isoform and size-specific.

    PubMed

    Dafnis, Ioannis; Argyri, Letta; Sagnou, Marina; Tzinia, Athina; Tsilibary, Effie C; Stratikos, Efstratios; Chroni, Angeliki

    2016-01-01

    The apolipoprotein (apo) E4 isoform is the strongest risk factor for late-onset Alzheimer's disease (AD). ApoE4 is more susceptible to proteolysis than apoE2 and apoE3 isoforms and carboxyl-terminal truncated apoE4 forms have been found in AD patients' brain. We have previously shown that a specific apoE4 fragment, apoE4-165, promotes amyloid-peptide beta 42 (Aβ42) accumulation in human neuroblastoma SK-N-SH cells and increased intracellular reactive oxygen species formation, two events considered to occur early in AD pathogenesis. Here, we show that these effects are allele-dependent and absolutely require the apoE4 background. Furthermore, the exact length of the fragment is critical since longer or shorter length carboxyl-terminal truncated apoE4 forms do not elicit the same effects. Structural and thermodynamic analyses showed that apoE4-165 has a compact structure, in contrast to other carboxyl-terminal truncated apoE4 forms that are instead destabilized. Compared however to other allelic backgrounds, apoE4-165 is structurally distinct and less thermodynamically stable suggesting that the combination of a well-folded structure with structural plasticity is a unique characteristic of this fragment. Overall, our findings suggest that the ability of apoE fragments to promote Aβ42 intraneuronal accumulation is specific for both the apoE4 isoform and the particular structural and thermodynamic properties of the fragment. PMID:27476701

  11. The ability of apolipoprotein E fragments to promote intraneuronal accumulation of amyloid beta peptide 42 is both isoform and size-specific

    PubMed Central

    Dafnis, Ioannis; Argyri, Letta; Sagnou, Marina; Tzinia, Athina; Tsilibary, Effie C.; Stratikos, Efstratios; Chroni, Angeliki

    2016-01-01

    The apolipoprotein (apo) E4 isoform is the strongest risk factor for late-onset Alzheimer’s disease (AD). ApoE4 is more susceptible to proteolysis than apoE2 and apoE3 isoforms and carboxyl-terminal truncated apoE4 forms have been found in AD patients’ brain. We have previously shown that a specific apoE4 fragment, apoE4-165, promotes amyloid-peptide beta 42 (Aβ42) accumulation in human neuroblastoma SK-N-SH cells and increased intracellular reactive oxygen species formation, two events considered to occur early in AD pathogenesis. Here, we show that these effects are allele-dependent and absolutely require the apoE4 background. Furthermore, the exact length of the fragment is critical since longer or shorter length carboxyl-terminal truncated apoE4 forms do not elicit the same effects. Structural and thermodynamic analyses showed that apoE4-165 has a compact structure, in contrast to other carboxyl-terminal truncated apoE4 forms that are instead destabilized. Compared however to other allelic backgrounds, apoE4-165 is structurally distinct and less thermodynamically stable suggesting that the combination of a well-folded structure with structural plasticity is a unique characteristic of this fragment. Overall, our findings suggest that the ability of apoE fragments to promote Aβ42 intraneuronal accumulation is specific for both the apoE4 isoform and the particular structural and thermodynamic properties of the fragment. PMID:27476701

  12. The ability of apolipoprotein E fragments to promote intraneuronal accumulation of amyloid beta peptide 42 is both isoform and size-specific.

    PubMed

    Dafnis, Ioannis; Argyri, Letta; Sagnou, Marina; Tzinia, Athina; Tsilibary, Effie C; Stratikos, Efstratios; Chroni, Angeliki

    2016-08-01

    The apolipoprotein (apo) E4 isoform is the strongest risk factor for late-onset Alzheimer's disease (AD). ApoE4 is more susceptible to proteolysis than apoE2 and apoE3 isoforms and carboxyl-terminal truncated apoE4 forms have been found in AD patients' brain. We have previously shown that a specific apoE4 fragment, apoE4-165, promotes amyloid-peptide beta 42 (Aβ42) accumulation in human neuroblastoma SK-N-SH cells and increased intracellular reactive oxygen species formation, two events considered to occur early in AD pathogenesis. Here, we show that these effects are allele-dependent and absolutely require the apoE4 background. Furthermore, the exact length of the fragment is critical since longer or shorter length carboxyl-terminal truncated apoE4 forms do not elicit the same effects. Structural and thermodynamic analyses showed that apoE4-165 has a compact structure, in contrast to other carboxyl-terminal truncated apoE4 forms that are instead destabilized. Compared however to other allelic backgrounds, apoE4-165 is structurally distinct and less thermodynamically stable suggesting that the combination of a well-folded structure with structural plasticity is a unique characteristic of this fragment. Overall, our findings suggest that the ability of apoE fragments to promote Aβ42 intraneuronal accumulation is specific for both the apoE4 isoform and the particular structural and thermodynamic properties of the fragment.

  13. Influence of Isoforms and Carboxyl-Terminal Truncations on the Capacity of Apolipoprotein E To Associate with and Activate Phospholipid Transfer Protein.

    PubMed

    Dafnis, Ioannis; Metso, Jari; Zannis, Vassilis I; Jauhiainen, Matti; Chroni, Angeliki

    2015-09-29

    Phospholipid transfer protein (PLTP), a main protein in lipid and lipoprotein metabolism, exists in high-activity (HA-PLTP) and low-activity (LA-PLTP) forms in human plasma. Proper phospholipid transfer activity of PLTP is modulated by interactions with various apolipoproteins (apo) including apoE. The domains of apoE involved in interactions with PLTP are not known. Here we analyzed the capacity of recombinant apoE isoforms and apoE4 mutants with progressive carboxyl-terminal deletions to bind to and activate HA-PLTP and LA-PLTP. Our analyses demonstrated that lipid-free apoE isoforms bind to both HA-PLTP and LA-PLTP, resulting in phospholipid transfer activation, with apoE3 inducing the highest PLTP activation. The isoform-specific differences in apoE/PLTP binding and PLTP activation were abolished following apoE lipidation. Lipid-free apoE4[Δ(260-299)], apoE4[Δ(230-299)], apoE4[Δ(203-299)], and apoE4[Δ(186-299)] activated HA-PLTP by 120-160% compared to full-length apoE4. Lipid-free apoE4[Δ(186-299)] also activated LA-PLTP by 85% compared to full-length apoE4. All lipidated truncated apoE4 forms displayed a similar effect on HA-PLTP and LA-PLTP activity as full-length apoE4. Strikingly, lipid-free or lipidated full-length apoE4 and apoE4[Δ(186-299)] demonstrated similar binding capacity to LA-PLTP and HA-PLTP. Biophysical studies showed that the carboxyl-terminal truncations of apoE4 resulted in small changes of the structural or thermodynamic properties of lipidated apoE4, that were much less pronounced compared to changes observed previously for lipid-free apoE4. Overall, our findings show an isoform-dependent binding to and activation of PLTP by lipid-free apoE. Furthermore, the domain of apoE4 required for PLTP activation resides within its amino-terminal 1-185 region. The apoE/PLTP interactions can be modulated by the conformation and lipidation state of apoE.

  14. Compared with saturated fatty acids, dietary monounsaturated fatty acids and carbohydrates increase atherosclerosis and VLDL cholesterol levels in LDL receptor-deficient, but not apolipoprotein E-deficient, mice.

    PubMed

    Merkel, M; Velez-Carrasco, W; Hudgins, L C; Breslow, J L

    2001-11-01

    Heart-healthy dietary recommendations include decreasing the intake of saturated fatty acids (SFA). However, the relative benefit of replacing SFA with monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), or carbohydrates (CARB) is still being debated. We have used two mouse models of atherosclerosis, low density lipoprotein receptor-deficient (LDLRKO) and apolipoprotein E-deficient (apoEKO) mice to measure the effects of four isocaloric diets enriched with either SFA, MUFA, PUFA, or CARB on atherosclerotic lesion area and lipoprotein levels. In LDLRKO mice, compared with the SFA diet, the MUFA and CARB diets significantly increased atherosclerosis in both sexes, but the PUFA diet had no effect. The MUFA and CARB diets also increased very low density lipoprotein-cholesterol (VLDL-C) and LDL-cholesterol (LDL-C) in males and VLDL-C levels in females. Analysis of data from LDLRKO mice on all diets showed that atherosclerotic lesion area correlated positively with VLDL-C levels (males: r = 0.47, P < 0.005; females: r = 0.52, P < 0.001). In contrast, in apoEKO mice there were no significant dietary effects on atherosclerosis in either sex. Compared with the SFA diet, the CARB diet significantly decreased VLDL-C in males and the MUFA, PUFA, and CARB diets decreased VLDL-C and the CARB diet decreased LDL-C in females. In summary, in LDLRKO mice the replacement of dietary SFA by either MUFA or CARB causes a proportionate increase in both atherosclerotic lesion area and VLDL-C. There were no significant dietary effects on atherosclerotic lesion area in apoEKO mice. These results are surprising and suggest that, depending on the underlying genotype, dietary MUFA and CARB can actually increase atherosclerosis susceptibility, probably by raising VLDL-C levels through a non-LDL receptor, apoE-dependent pathway. PMID:11606787

  15. The effect of galantamine on brain atrophy rate in subjects with mild cognitive impairment is modified by apolipoprotein E genotype: post-hoc analysis of data from a randomized controlled trial

    PubMed Central

    2014-01-01

    Introduction The aim of this investigation was to assess the effect of galantamine, an acetylcholinesterase inhibitor and allosteric modulator of nicotinic receptors, on brain atrophy in individuals with mild cognitive impairment (MCI), and to assess effect modification by apolipoprotein E (APOE) genotype. Methods We used data from the Galantamine-International-11 (Gal-Int-11) trial, a 24-month, randomized, double blind, placebo-controlled, flexible-dose (16 to 24 mg daily) study in patients with MCI. Brain magnetic resonance imaging (MRI), including a 3-dimensional T1-weighted gradient echo volumetric sequence, was performed at screening and at 24 months. We recorded whole brain and hippocampal volumes, and calculated annual atrophy rates. Linear regression analysis was used to calculate adjusted mean differences in the rate of whole brain and hippocampal atrophy, between MCI patients treated with galantamine and with placebo. Additionally, we performed stratified analyses according to APOE genotype. Results Data from 364 MCI patients with 24-month MRI data (galantamine, n = 176; placebo, n = 188) were included in the volumetric analysis. Subjects treated with galantamine demonstrated a lower rate of whole brain atrophy compared to those treated with placebo (adjusted mean difference 0.18% per year (95% confidence interval (CI) 0.04; 0.30)). Stratified analyses according to APOE genotype, showed that this effect was confined to patients who carried an APOE ϵ4 allele (adjusted mean difference 0.28% per year (95% CI 0.07; 0.50)). Rates of hippocampal atrophy did not differ significantly between study groups. Conclusions Patients with MCI who were treated with galantamine demonstrated a lower rate of whole brain atrophy, but not of hippocampal atrophy, over a 24-month treatment period, compared to those treated with placebo. This protective effect of galantamine on whole brain atrophy rate in MCI was only present in APOE ϵ4 carriers. PMID:25478019

  16. The role of Alzheimer’s and cerebrovascular pathology in mediating the effects of age, race, and apolipoprotein E genotype on dementia severity in pathologically confirmed Alzheimer’s disease

    PubMed Central

    Gavett, Brandon E.; John, Samantha E.; Gurnani, Ashita S.; Bussell, Cara A.; Saurman, Jessica L.

    2016-01-01

    Background Dementia severity can be modeled as the construct δ, representing the “cognitive correlates of functional status.” Objective We recently validated a model for estimating δ in the National Alzheimer’s Coordinating Center’s Uniform Data Set; however, δ’s association with neuropathology remains untested. Methods We used data from 727 decedents evaluated at Alzheimer’s Disease (AD) Centers nationwide. Participants spoke English, had no genetic abnormalities, and were pathologically diagnosed with AD as a primary or contributing etiology. Clinical data from participants’ last visit prior to death were used to estimate dementia severity (δ). Results A structural equation model using age, education, race, and apolipoprotein E (APOE) genotype (number of ε2 and ε4 alleles) as predictors and latent AD pathology and cerebrovascular disease (CVD) pathology as mediators fit the data well (RMSEA = 0.031; CFI = .957). AD pathology mediated the effects of age and APOE genotype on dementia severity. An older age at death and more ε2 alleles were associated with less AD pathology and, in turn, with less severe dementia. In contrast, more ε4 alleles were associated with more pathology and more severe dementia. Although age and race contributed to differences in CVD pathology, CVD pathology was not related to dementia severity in this sample of decedents with pathologically confirmed AD. Conclusions Using δ as an estimate of dementia severity fits well within a structural model in which AD pathology directly affects dementia severity and mediates the relationship between age and APOE genotype on dementia severity. PMID:26444761

  17. Spectroscopy of dimers.

    NASA Technical Reports Server (NTRS)

    Levine, H. B.

    1972-01-01

    The method of Stogryn and Hirschfelder, which divides two-particle phase space into bound, metastable, and free particle parts, is applied to the statistical averages which determine the first three spectroscopic moments of 'collision-induced' far-infrared and Raman spectra. Numerical results are presented for a number of models of noble gas systems. It is shown that for some systems, but not all, dimers make important, although not necessarily well-separated, contributions to the spectrum.

  18. Molecular Basis for Increased Risk for Late-onset Alzheimer Disease Due to the Naturally Occurring L28P Mutation in Apolipoprotein E4*

    PubMed Central

    Argyri, Letta; Dafnis, Ioannis; Theodossiou, Theodossis A.; Gantz, Donald; Stratikos, Efstratios; Chroni, Angeliki

    2014-01-01

    The apolipoprotein (apo) E4 isoform has consistently emerged as a susceptibility factor for late-onset Alzheimer disease (AD), although the exact mechanism is not clear. A rare apoE4 mutant, apoE4[L28P] Pittsburgh, burdens carriers with an added risk for late-onset AD and may be a useful tool for gaining insights into the role of apoE4 in disease pathogenesis. Toward this end, we evaluated the effect of the L28P mutation on the structural and functional properties of apoE4. ApoE4[L28P] was found to have significantly perturbed thermodynamic properties, to have reduced helical content, and to expose a larger portion of the hydrophobic surface to the solvent. Furthermore, this mutant is thermodynamically destabilized and more prone to proteolysis. When interacting with lipids, apoE4[L28P] formed populations of lipoprotein particles with structural defects. The structural perturbations brought about by the mutation were accompanied by aberrant functions associated with the pathogenesis of AD. Specifically, apoE4[L28P] promoted the cellular uptake of extracellular amyloid β peptide 42 (Aβ42) by human neuroblastoma SK-N-SH cells as well as by primary mouse neuronal cells and led to increased formation of intracellular reactive oxygen species that persisted for at least 24 h. Furthermore, lipoprotein particles containing apoE4[L28P] induced intracellular reactive oxygen species formation and reduced SK-N-SH cell viability. Overall, our findings suggest that the L28P mutation leads to significant structural and conformational perturbations in apoE4 and can induce functional defects associated with neuronal Aβ42 accumulation and oxidative stress. We propose that these structural and functional changes underlie the observed added risk for AD development in carriers of apoE4[L28P]. PMID:24644280

  19. Molecular basis for increased risk for late-onset Alzheimer disease due to the naturally occurring L28P mutation in apolipoprotein E4.

    PubMed

    Argyri, Letta; Dafnis, Ioannis; Theodossiou, Theodossis A; Gantz, Donald; Stratikos, Efstratios; Chroni, Angeliki

    2014-05-01

    The apolipoprotein (apo) E4 isoform has consistently emerged as a susceptibility factor for late-onset Alzheimer disease (AD), although the exact mechanism is not clear. A rare apoE4 mutant, apoE4[L28P] Pittsburgh, burdens carriers with an added risk for late-onset AD and may be a useful tool for gaining insights into the role of apoE4 in disease pathogenesis. Toward this end, we evaluated the effect of the L28P mutation on the structural and functional properties of apoE4. ApoE4[L28P] was found to have significantly perturbed thermodynamic properties, to have reduced helical content, and to expose a larger portion of the hydrophobic surface to the solvent. Furthermore, this mutant is thermodynamically destabilized and more prone to proteolysis. When interacting with lipids, apoE4[L28P] formed populations of lipoprotein particles with structural defects. The structural perturbations brought about by the mutation were accompanied by aberrant functions associated with the pathogenesis of AD. Specifically, apoE4[L28P] promoted the cellular uptake of extracellular amyloid β peptide 42 (Aβ42) by human neuroblastoma SK-N-SH cells as well as by primary mouse neuronal cells and led to increased formation of intracellular reactive oxygen species that persisted for at least 24 h. Furthermore, lipoprotein particles containing apoE4[L28P] induced intracellular reactive oxygen species formation and reduced SK-N-SH cell viability. Overall, our findings suggest that the L28P mutation leads to significant structural and conformational perturbations in apoE4 and can induce functional defects associated with neuronal Aβ42 accumulation and oxidative stress. We propose that these structural and functional changes underlie the observed added risk for AD development in carriers of apoE4[L28P].

  20. Apolipoprotein E LDL receptor-binding domain-containing high-density lipoprotein: a nanovehicle to transport curcumin, an antioxidant and anti-amyloid bioflavonoid.

    PubMed

    Khumsupan, Panupon; Ramirez, Ricardo; Khumsupan, Darin; Narayanaswami, Vasanthy

    2011-01-01

    Curcumin is an antioxidant and anti-inflammatory bioflavonoid that has been recently identified as an anti-amyloid agent as well. To make it more available in its potent form as a potential amyloid disaggregation agent, we employed high-density lipoproteins (HDL), which are lipid-protein complexes that transport plasma cholesterol, to transport curcumin. The objective of this study was to employ reconstituted HDL containing human apoE3 N-terminal (NT) domain, as a vehicle to transport curcumin. The NT domain serves as a ligand to mediate binding and uptake of lipoprotein complexes via the low-density lipoprotein receptor (LDLr) family of proteins located at the cell surface. Reconstituted HDL was prepared with phospholipids and recombinant apoE3-NT domain in the absence or presence of curcumin. Non-denaturing polyacrylamide gel electrophoresis indicated that the molecular mass and Stokes' diameter of HDL bearing curcumin were ~670kDa and ~17nm, respectively, while electron microscopy revealed the presence of discoidal particles. Fluorescence emission spectra of HDL bearing (the intrinsically fluorescent) curcumin indicated that the wavelength of maximal fluorescence emission (λ(max)) of curcumin was ~495nm, which is highly blue-shifted compared to λ(max) of curcumin in solvents of varying polarity (λ(max) ranging from 515-575nm) or in aqueous buffers. In addition, an enormous enhancement in fluorescence emission intensity was noted in curcumin-containing HDL compared to curcumin in aqueous buffers. Curcumin fluorescence emission was quenched to a significant extent by lipid-based quenchers but not by aqueous quenchers. These observations indicate that curcumin has partitioned efficiently into the hydrophobic milieu of the phospholipid bilayer of HDL. Functional assays indicated that the LDLr-binding ability of curcumin-containing HDL with apoE3-NT is similar to that of HDL without curcumin. Taken together, we report that apoE-containing HDL has a tremendous

  1. Dimer vacancy interactions on the Si(0 0 1) surface

    NASA Astrophysics Data System (ADS)

    Chang, Jianlin; Stott, M. J.

    1998-07-01

    Dimer vacancy (DV) interactions on the Si(0 0 1) surface are studied using ab initio total energy calculations. Two kinds of DVs are considered: single DV (1-DV) and a DV cluster composed of two single DVs in the nearest-neighbor positions on the same dimer row (2-DV). Calculation of the total energy as a function of DV separation gives the DV interaction energy. Attractive interactions between 1-DVs on the same dimer row and 2-DVs on neighboring dimer rows are found which provide an explanation of the experimentally observed formation of 2-DVs, the aligning of 2-DVs in the direction perpendicular to the dimer row to form long extended DV lines, and subsequently, the formation of 2× n periodic structures on the surface.

  2. Condensation in CO2 free jet expansions. I - Dimer formation.

    NASA Technical Reports Server (NTRS)

    Dorfeld, W. G.; Hudson, J. B.

    1973-01-01

    A theoretical and experimental investigation of the kinetics of CO2 dimer formation in the adiabatically expanding core of a free jet expansion has been carried out. The theoretical analysis is based on dimer formation by an efficient termolecular process and dimer destruction by bimolecular collisions. Account is taken of the expected variation of the specific heat ratio during the expansion and of the effective increase in the termolecular collision rate at low temperatures due to the presence of loosely bound orbiting pairs. Experimental dimer concentrations were measured mass spectrometrically by forming a molecular beam from the expanded gas mixture after the onset of molecular flow. Observed dimer concentrations, for a range of pre-expansion conditions of 400 to 900 torr pressure and room temperature, are in good agreement with the theoretical analysis, provided that account is taken of the effect of loosely bound orbiting pairs at low temperatures.

  3. A variant form of the human deleted in malignant brain tumor 1 (DMBT1) gene shows increased expression in inflammatory bowel diseases and interacts with dimeric trefoil factor 3 (TFF3).

    PubMed

    Madsen, Jens; Sorensen, Grith Lykke; Nielsen, Ole; Tornøe, Ida; Thim, Lars; Fenger, Claus; Mollenhauer, Jan; Holmskov, Uffe

    2013-01-01

    The protein deleted in malignant brain tumors (DMBT1) and the trefoil factor (TFF) proteins have all been proposed to have roles in epithelial cell growth and cell differentiation and shown to be up regulated in inflammatory bowel diseases. A panel of monoclonal antibodies was raised against human DMBT1(gp340). Analysis of lung washings and colon tissue extracts by Western blotting in the unreduced state, two antibodies (Hyb213-1 and Hyb213-6) reacted with a double band of 290 kDa in lung lavage. Hyb213-6, in addition, reacted against a double band of 270 kDa in colon extract while Hyb213-1 showed no reaction. Hyb213-6 showed strong cytoplasmic staining in epithelial cells of both the small and large intestine whereas no staining was seen with Hyb213-1. The number of DMBT1(gp340) positive epithelial cells, stained with Hyb213-6, was significantly up regulated in inflammatory colon tissue sections from patients with ulcerative colitis (p<0.0001) and Crohn's disease (p = 0.006) compared to normal colon tissue. Immunohistochemical analysis of trefoil factor TFF1, 2 and 3 showed that TFF1 and 3 localized to goblet cells in both normal colon tissue and in tissue from patients with ulcerative colitis or Crohn's disease. No staining for TFF2 was seen in goblet cells in normal colon tissue whereas the majority of tissue sections in ulcerative colitis and Crohn's disease showed sparse and scattered TFF2 positive goblet cells. DMBT1 and TFF proteins did therefore not co-localize in the same cells but localized in adjacent cells in the colon. The interaction between DMBT1(gp340) and trefoil TFFs proteins was investigated using an ELISA assay. DMBT1(gp340) bound to solid-phase bound recombinant dimeric TFF3 in a calcium dependent manner (p<0.0001) but did not bind to recombinant forms of monomeric TFF3, TFF2 or glycosylated TFF2. This implies a role for DMBT1 and TFF3 together in inflammatory bowel disease.

  4. Calcium-dependent Dimerization of Human Soluble Calcium Activated Nucleotidase: Characterization of the Dimer Interface

    SciTech Connect

    Yang,M.; Horii, K.; Herr, A.; Kirley, T.

    2006-01-01

    Mammals express a protein homologous to soluble nucleotidases used by blood-sucking insects to inhibit host blood clotting. These vertebrate nucleotidases may play a role in protein glycosylation. The activity of this enzyme family is strictly dependent on calcium, which induces a conformational change in the secreted, soluble human nucleotidase. The crystal structure of this human enzyme was recently solved; however, the mechanism of calcium activation and the basis for the calcium-induced changes remain unclear. In this study, using analytical ultracentrifugation and chemical cross-linking, we show that calcium or strontium induce noncovalent dimerization of the soluble human enzyme. The location and nature of the dimer interface was elucidated using a combination of site-directed mutagenesis and chemical cross-linking, coupled with crystallographic analyses. Replacement of Ile{sup 170}, Ser{sup 172}, and Ser{sup 226} with cysteine residues resulted in calcium-dependent, sulfhydryl-specific intermolecular cross-linking, which was not observed after cysteine introduction at other surface locations. Analysis of a super-active mutant, E130Y, revealed that this mutant dimerized more readily than the wild-type enzyme. The crystal structure of the E130Y mutant revealed that the mutated residue is found in the dimer interface. In addition, expression of the full-length nucleotidase revealed that this membrane-bound form can also dimerize and that these dimers are stabilized by spontaneous oxidative cross-linking of Cys{sup 30}, located between the single transmembrane helix and the start of the soluble sequence. Thus, calcium-mediated dimerization may also represent a mechanism for regulation of the activity of this nucleotidase in the physiological setting of the endoplasmic reticulum or Golgi.

  5. ApoE (Apolipoprotein E) Genotyping

    MedlinePlus

    ... There are no clear-cut tests to diagnose Alzheimer disease during life. Health practitioners can, however, make a reasonably accurate clinical diagnosis of AD by ruling out other potential causes of dementia and checking for a genetic predisposition to AD with APOE genotyping as supplemental ...

  6. Apolipoprotein E: from lipid transport to neurobiology.

    PubMed

    Hauser, Paul S; Narayanaswami, Vasanthy; Ryan, Robert O

    2011-01-01

    Apolipoprotein (apo) E has a storied history as a lipid transport protein. The integral association between cholesterol homeostasis and lipoprotein clearance from circulation are intimately related to apoE's function as a ligand for cell-surface receptors of the low-density lipoprotein receptor family. The receptor binding properties of apoE are strongly influenced by isoform specific amino acid differences as well as the lipidation state of the protein. As understanding of apoE as a structural component of circulating plasma lipoproteins has evolved, exciting developments in neurobiology have revitalized interest in apoE. The strong and enduring correlation between the apoE4 isoform and age of onset and increased risk of Alzheimer's disease has catapulted apoE to the forefront of neurobiology. Using genetic tools generated for study of apoE lipoprotein metabolism, transgenic "knock-in" and gene-disrupted mice are now favored models for study of its role in a variety of neurodegenerative diseases. Key structural knowledge of apoE and isoform-specific differences is driving research activity designed to elucidate how a single amino acid change can manifest such profoundly significant pathological consequences. This review describes apoE through a lens of structure-based knowledge that leads to hypotheses that attempt to explain the functions of apoE and isoform-specific effects relating to disease mechanism.

  7. [Dichotomizing method applied to calculating equilibrium constant of dimerization system].

    PubMed

    Cheng, Guo-zhong; Ye, Zhi-xiang

    2002-06-01

    The arbitrary trivariate algebraic equations are formed based on the combination principle. The univariata algebraic equation of equilibrium constant kappa for dimerization system is obtained through a series of algebraic transformation, and it depends on the properties of monotonic functions whether the equation is solvable or not. If the equation is solvable, equilibrium constant of dimerization system is obtained by dichotomy and its final equilibrium constant of dimerization system is determined according to the principle of error of fitting. The equilibrium constants of trisulfophthalocyanine and biosulfophthalocyanine obtained with this method are 47,973.4 and 30,271.8 respectively. The results are much better than those reported previously.

  8. Relationship between hemodynamics and atherosclerosis in aortic arches of apolipoprotein E-null mice on 129S6/SvEvTac and C57BL/6J genetic backgrounds

    PubMed Central

    Tomita, Hirofumi; Hagaman, John; Friedman, Morton H.; Maeda, Nobuyo

    2011-01-01

    Objective We investigated the relationships between hemodynamics and differential plaque development at the aortic arch of apolipoprotein E (apoE)-null mice on 129S6/SvEvTac (129) and C57BL/6J (B6) genetic backgrounds. Methods Mean flow velocities at the ascending and descending aorta (mVAA and mVDA) were measured by Doppler ultrasound in wild type and apoE-null male mice at 3 and 9 months of age. Following dissection of the aortic arches, anatomical parameters and plaque areas were evaluated. Results Arch plaques were five times bigger in 129-apoE than in B6-apoE mice at 3 months, and twice as large at 9 months. The geometric differences, namely larger vessel diameter in the B6 strain and broader inner curvature of the aortic arch in the 129 strain, were exaggerated in 9-month-old apoE-null mice. Cardiac output and heart rate under anesthesia were significantly higher in the B6 strain than in the 129 strain. The values of mVAA were similar in the two strains, while mVDA was lower in the 129 strain. However, there was a 129-apoE-specific reduction of flow velocities with age, and both mVAA and mVDA were significantly lower in 129-apoE than in B6-apoE mice at 9 months. The mean relative wall shear stress (rWSS) over the aortic arch in 129-apoE and B6-apoE mice were not different, but animals with lower mean rWSS had larger arch plaques within each strain. Conclusions The plaque formation in the arch of apoE-null mice is accompanied by strain-dependent changes in both arch geometry and hemodynamics. While arch plaque sizes negatively correlate with mean rWSS, additional factors are necessary to account for the strain differences in arch plaque development. PMID:22078246

  9. Increased apolipoprotein E and c-fms gene expression without elevated interleukin 1 or 6 mRNA levels indicates selective activation of macrophage functions in advanced human atheroma.

    PubMed Central

    Salomon, R N; Underwood, R; Doyle, M V; Wang, A; Libby, P

    1992-01-01

    Cells found within atherosclerotic lesions can produce in culture protein mediators that may participate in atherogenesis. To test whether human atheromata actually contain transcripts for certain of these genes, we compared levels of mRNAs in carotid or coronary atheromata and in nonatherosclerotic human vessels by polymerase chain reaction (PCR) amplification of cDNAs reverse-transcribed from RNA. We measured PCR products (generated during exponential amplification) by incorporation of 32P-labeled primers. Levels of interleukin 1 alpha, 1 beta, or 6 mRNAs in plaques and controls did not differ. Compared to uninvolved vessels, plaques did contain higher levels of mRNA encoding platelet-derived growth factor A chain (42 +/- 24 vs. 12 +/- 10 fmol of product; mean +/- SD; n = 8 and 8, respectively; P = 0.007) and B chain (41 +/- 36 vs. 4 +/- 3 fmol of product, n = 14 and 6, respectively; P = 0.024). Atherosclerotic lesions consistently had much higher levels of apolipoprotein E (apoE) mRNA than did control vessels (131 +/- 71 vs. 5 +/- 3 fmol of product; n = 12 and 10, respectively; P less than 0.001). Direct RNA blot analyses confirmed elevated levels of apoE mRNA in plaque extracts. To test whether mononuclear phagocytes might be a source of the apoE mRNA, we studied a selective marker for cells of the monocytic lineage, the c-fms protooncogene, which encodes the receptor for macrophage colony-stimulating factor. Plaques also contained elevated levels of c-fms mRNA (30 +/- 17 vs. 5 +/- 3 fmol of product; n = 10 and 7, respectively; P = 0.002). Immunohistochemical colocalization demonstrated apoE protein in association with macrophages in plaques, whereas nonatherosclerotic vessels showed no immunoreactive apoE. ApoE produced locally in atheroma might modulate the functions of lesional T cells or promote "reverse cholesterol transport" by associating with high density lipoprotein particles, thus targeting them for peripheral uptake. Macrophages within the advanced

  10. Dimer model for Tau proteins bound in microtubule bundles

    NASA Astrophysics Data System (ADS)

    Hall, Natalie; Kluber, Alexander; Hayre, N. Robert; Singh, Rajiv; Cox, Daniel

    2013-03-01

    The microtubule associated protein tau is important in nucleating and maintaining microtubule spacing and structure in neuronal axons. Modification of tau is implicated as a later stage process in Alzheimer's disease, but little is known about the structure of tau in microtubule bundles. We present preliminary work on a proposed model for tau dimers in microtubule bundles (dimers are the minimal units since there is one microtubule binding domain per tau). First, a model of tau monomer was created and its characteristics explored using implicit solvent molecular dynamics simulation. Multiple simulations yield a partially collapsed form with separate positively/negatively charged clumps, but which are a factor of two smaller than required by observed microtubule spacing. We argue that this will elongate in dimer form to lower electrostatic energy at a cost of entropic ``spring'' energy. We will present preliminary results on steered molecular dynamics runs on tau dimers to estimate the actual force constant. Supported by US NSF Grant DMR 1207624.

  11. Versatile SPR aptasensor for detection of lysozyme dimer in oligomeric and aggregated mixtures.

    PubMed

    Vasilescu, Alina; Purcarea, Cristina; Popa, Elena; Zamfir, Medana; Mihai, Iuliana; Litescu, Simona; David, Sorin; Gaspar, Szilveszter; Gheorghiu, Mihaela; Jean-Louis Marty

    2016-09-15

    A Surface Plasmon Resonance (SPR) sensor for the quantitation of lysozyme dimer in monomer-dimer mixtures, reaching a detection limit of 1.4nM dimer, has been developed. The sensor is based on an aptamer which, although developed for the monomeric form, binds also the dimeric form but with a strikingly different kinetics. The aptasensor was calibrated using a dimer obtained by cross-linking. Sensorgrams acquired with the aptasensor in monomer-dimer mixtures were analysed using Principal Components Analysis and Multiple Regression to establish correlations with the dimer content in the mixtures. The method allows the detection of 0.1-1% dimer in monomer solutions without any separation. As an application, the aptasensor was used to qualitatively observe the initial stages of aggregation of lysozyme solutions at 60°C and pH 2, through the variations in lysozyme dimer amounts. Several other methods were used to characterize the lysozyme dimer obtained by cross-linking and confirm the SPR results. This work highlights the versatility of the aptasensor, which can be used, by simply tuning the experimental conditions, for the sensitive detection of either the monomer or the dimer and for the observation of the aggregation process of lysozyme.

  12. An algebra of dimerization and its implications for G-protein coupled receptor signaling.

    PubMed

    Woolf, Peter J; Linderman, Jennifer J

    2004-07-21

    Many species of receptors form dimers, but how can we use this information to make predictions about signal transduction? This problem is particularly difficult when receptors dimerize with many different species, leading to a combinatoric increase in the possible number of dimer pairs. As an example system, we focus on receptors in the G-protein coupled receptor (GPCR) family. GPCRs have been shown to reversibly form dimers, but this dimerization does not directly affect signal transduction. Here we present a new theoretical framework called a dimerization algebra. This algebra provides a systematic and rational way to represent, manipulate, and in some cases simplify large and often complicated networks of dimerization interactions. To compliment this algebra, Monte Carlo simulations are used to predict dimerization's effect on receptor organization on the membrane, signal transduction, and internalization. These simulation results are directly comparable to various experimental measures such as fluorescence resonance energy transfer (FRET), and as such provide a link between the dimerization algebra and experimental data. As an example, we show how the algebra and computational results can be used to predict the effects of dimerization on the dopamine D2 and somatastatin SSTR1 receptors. When these predictions were compared to experimental findings from the literature, good agreement was found, demonstrating the utility of our approach. Applications of this work to the development of a novel class of dimerization-modulating drugs are also discussed.

  13. Structure and NLO properties of halogen (F, Cl) substituted formic acid dimers.

    PubMed

    Umadevi, P; Senthilkumar, L; Gayathri, M; Kolandaivel, P

    2014-11-11

    In this work, using ab initio and density functional theory (DFT) methods halogen substituted formic acid (FA) dimer is studied. The dimer stability is due to the hydrogen bonds, either conventional (OH⋯O, OH⋯F, OH⋯Cl) or non-conventional (CH⋯O, CH⋯F, CH⋯Cl). Among all the dimers, trans-trans form is more stable than the trans-cis, and cis-cis form. Basis set extrapolated counterpoise corrected interaction energy results for the FA dimer are in excellent agreement with BSSE corrected MP2 interaction energy. Symmetry Adopted Perturbation Theory (SAPT) analysis reveals that the electrostatic effect plays a dominant role in stabilization among the dimers with maximum interaction energy. Chlorine substituted FA dimer has high hyperpolarizability, which makes them excellent candidate for nonlinear optical materials (NLO). The halogen substituted formic acid dimers have higher stability and polarizability value than the unsubstituted formic acid dimer. The hyperpolarizability values depend on the geometrical structures of halogenated formic acid dimers than the type of hydrogen bonds. The small excitation energy and HOMO-LUMO gap in the halogenated formic acid dimer has led to the strong nonlinear optical response. The depolarization ratio and Rayleigh scattering increases in formic acid dimer after the halogen atom substitution.

  14. Final report on the amended safety assessment of diisopropyl dimer dilinoleate, dicetearyl dimer dilinoleate, diisostearyl dimer dilinoleate, dioctyl dimer dilinoleate, dioctyldodecyl dimer dilinoleate, and ditridecyl dimer dilinoleate.

    PubMed

    Fiume, Monice Zondlo

    2003-01-01

    Diisopropyl Dimer Dilinoleate, Dicetearyl Dimer Dilinoleate, Diisostearyl Dimer Dilinoleate, Dioctyl Dimer Dilinoleate, Dioctyldodecyl Dimer Dilinoleate, and Ditridecyl Dimer Dilinoleate are diesters of their respective alcohols and dilinoleic acid. They function as skin-conditioning agents in a variety of cosmetic products at concentrations around 10%, but may be used at concentrations up to 53% in lipsticks. These ingredients do not absorb radiation in the ultraviolet (UV) UVA or UVB range and the only impurities expected are <0.5% dilinoleic acid, <0.1% isopropyl alcohol or <1% isostearyl alcohol, and/or small amounts of dilinoleic acid and cetearyl alcohol or octyldodecanol, depending on which diester is used. The potential skin penetration of these ingredients was evaluated using an estimate of the octanol/water partition coefficient (logP of 17.7) based on the structure of Diisopropyl Dimer Dilinoleate. This is consistent with the insolubility of these ingredients in water. Safety test data on dilinoleic acid (no adverse effects) were considered relevant because dilinoleic acid is a component of these diesters and a likely breakdown product. The acute oral and dermal LD(50) values for rats of Diisopropyl, Diisostearyl, and Dioctyldodecyl Dimer Dilinoleate were >5.0 g/kg. In a subchronic feeding study, macrophage aggregation was seen in the mesenteric lymph node at the lowest dose level (0.1% in the diet). These ingredients did not produce skin or ocular irritation in animal tests, nor were they comedogenic. Ames testing, clastogenesis in human lymphocytes in culture, and L5178Y mouse lymphoma cell forward mutations were all negative, indicating no dilinoleic acid genotoxicity. No carcinogenicity or reproductive/developmental toxicity data were available; however, structural alerts that would suggest a mutagenic or carcinogenic risk are absent. Significant reproductive/developmental toxicity or other systemic toxicity is not expected with these ingredients

  15. Human Erythropoietin Dimers with Markedly Enhanced in vivo Activity

    NASA Astrophysics Data System (ADS)

    Sytkowski, Arthur J.; Dotimas Lunn, Elizabeth; Davis, Kerry Lynn; Feldman, Laurie; Siekman, Suvia

    1998-02-01

    Human erythropoietin, a widely used and important therapeutic glycoprotein, has a relatively short plasma half-life due to clearance by glomerular filtration as well as by other mechanisms. We hypothesized that an erythropoietin species with a larger molecular size would exhibit an increased plasma half-life and, potentially, an enhanced biological activity. We now report the production of biologically active erythropoietin dimers and trimers by chemical crosslinking of the conventional monomeric form. We imparted free sulfhydryl residues to a pool of erythropoietin monomer by chemical modification. A second pool was reacted with another modifying reagent to yield monomer with male-imido groups. Upon mixing these two pools, covalently linked dimers and trimers were formed that were biologically active in vitro. The plasma half-life of erythropoietin dimers in rabbits was >24 h compared with 4 h for the monomers. Importantly, erythropoietin dimers were biologically active in vivo as shown by their ability to increase the hematocrits of mice when injected subcutaneously. In addition, the dimers exhibited >26-fold higher activity in vivo than did the monomers and were very effective after only one dose. Dimeric and other oligomeric forms of Epo may have an important role in therapy.

  16. Lipid-directed vinculin dimerization.

    PubMed

    Chinthalapudi, Krishna; Patil, Dipak N; Rangarajan, Erumbi S; Rader, Christoph; Izard, Tina

    2015-05-01

    Vinculin localizes to cellular adhesions where it regulates motility, migration, development, wound healing, and response to force. Importantly, vinculin loss results in cancer phenotypes, cardiovascular disease, and embryonic lethality. At the plasma cell membrane, the most abundant phosphoinositide, phosphatidylinositol 4,5-bisphosphate (PIP2), binds the vinculin tail domain, Vt, and triggers homotypic and heterotypic interactions that amplify binding of vinculin to the actin network. Binding of PIP2 to Vt is necessary for maintaining optimal focal adhesions, for organizing stress fibers, for cell migration and spreading, and for the control of vinculin dynamics and turnover of focal adhesions. While the recently determined Vt/PIP2 crystal structure revealed the conformational changes occurring upon lipid binding and oligomerization, characterization of PIP2-induced vinculin oligomerization has been challenging in the adhesion biology field. Here, via a series of novel biochemical assays not performed in previous studies that relied on chemical cross-linking, we characterize the PIP2-induced vinculin oligomerization. Our results show that Vt/PIP2 forms a tight dimer with Vt or with the muscle-specific vinculin isoform, metavinculin, at sites of adhesion at the cell membrane. Insight into how PIP2 regulates clustering and into mechanisms that regulate cell adhesion allows the development for a more definite sensor for PIP2, and our developed techniques can be applied generally and thus open the door for the characterization of many other protein/PIP2 complexes under physiological conditions. PMID:25880222

  17. Lipid-directed vinculin dimerization.

    PubMed

    Chinthalapudi, Krishna; Patil, Dipak N; Rangarajan, Erumbi S; Rader, Christoph; Izard, Tina

    2015-05-01

    Vinculin localizes to cellular adhesions where it regulates motility, migration, development, wound healing, and response to force. Importantly, vinculin loss results in cancer phenotypes, cardiovascular disease, and embryonic lethality. At the plasma cell membrane, the most abundant phosphoinositide, phosphatidylinositol 4,5-bisphosphate (PIP2), binds the vinculin tail domain, Vt, and triggers homotypic and heterotypic interactions that amplify binding of vinculin to the actin network. Binding of PIP2 to Vt is necessary for maintaining optimal focal adhesions, for organizing stress fibers, for cell migration and spreading, and for the control of vinculin dynamics and turnover of focal adhesions. While the recently determined Vt/PIP2 crystal structure revealed the conformational changes occurring upon lipid binding and oligomerization, characterization of PIP2-induced vinculin oligomerization has been challenging in the adhesion biology field. Here, via a series of novel biochemical assays not performed in previous studies that relied on chemical cross-linking, we characterize the PIP2-induced vinculin oligomerization. Our results show that Vt/PIP2 forms a tight dimer with Vt or with the muscle-specific vinculin isoform, metavinculin, at sites of adhesion at the cell membrane. Insight into how PIP2 regulates clustering and into mechanisms that regulate cell adhesion allows the development for a more definite sensor for PIP2, and our developed techniques can be applied generally and thus open the door for the characterization of many other protein/PIP2 complexes under physiological conditions.

  18. Rotational spectra of propargyl alcohol dimer: A dimer bound with three different types of hydrogen bonds

    SciTech Connect

    Mani, Devendra; Arunan, E.

    2014-10-28

    Pure rotational spectra of the propargyl alcohol dimer and its three deuterium isotopologues have been observed in the 4 to 13 GHz range using a pulsed-nozzle Fourier transform microwave spectrometer. For the parent dimer, a total of 51 transitions could be observed and fitted within experimental uncertainty. For two mono-substituted and one bi-substituted deuterium isotopologues, a total of 14, 17, and 19 transitions were observed, respectively. The observed rotational constants for the parent dimer [A = 2321.8335(4) MHz, B = 1150.4774(2) MHz, and C = 1124.8898(2) MHz] are close to those of the most stable structure predicted by ab initio calculations. Spectra of the three deuterated isotopologues and Kraitchman analysis positively confirm this structure. Geometrical parameters and “Atoms in Molecules” analysis on the observed structure reveal that the two propargyl alcohol units in the dimer are bound by three different types of hydrogen bonds: O–H⋯O, O–H⋯π, and C–H⋯π. To the best of our knowledge, propargyl alcohol seems to be the smallest molecule forming a homodimer with three different points of contact.

  19. Intermolecular dimerization with pillared layered clay templates.

    SciTech Connect

    Wiederrecht, G. P.; Sandi, G.; Carrado, K. A.; Seifert, S.; Chemistry

    2001-11-19

    Solutions of pyrene in the presence of a pillared, layered montmorillonite clay produce hybrid organic-inorganic materials with substantial molecular loading in the gallery regions between the clay layers. The results are in sharp contrast to other aromatics, such as benzene, naphthalene, or perylene, which show minimal incorporation of the molecules into the gallery regions of the clay. We present evidence that the unusual affinity for pyrene to form intermolecular dimers is the reason for the high loading. Pyrene monomers are easily introduced to the layers. Through steric hindrance, subsequent intermolecular dimer formation is allowed, and they are captured by the pillared, layered structure. CW and time-resolved emission spectra strongly indicate the presence of face-to-face intermolecular dimers (excimers) within the clay galleries. The combination of the ease of high molecular loading into an inorganic, high aspect ratio template and the collective optical properties of the organic layer may be useful as a new means to create hybrid structures.

  20. Plasmon hybridization in nanoparticle dimers

    NASA Astrophysics Data System (ADS)

    Nordlander, Peter; Prodan, Emil; Oubre, Chris

    2004-03-01

    We apply the recently developed plasmon hybridization method (Science 302(2003)419-422) to solid sphere and nanoshell dimers. The results provide a simple and intuitive description of how the energy and excitation cross sections of the dimer plasmons depend on nanoparticle separation, D. We show that the dimer plasmons can be viewed as bonding and antibonding combinations, i.e. hybridization of the individual nanoparticle plasmons. For large D, the shifts of the dipolar dimer plasmons essentially follow the interaction energy between two classical dipoles (1/D^3). As D becomes smaller, the shifts of the dipolar dimer plasmons becomes much stronger and varies much faster with D due to the interaction of the dipolar plasmon of an individual particle with higher energy multipolar plasmons of the other particle. For the heterodimer, the hybridization between the individual nanoparticle plasmons on the different particles result in dimer plasmons whose energies as a function of D exhibit avoided crossings and other interesting effects. The results are compared with FDTD calculations. Work supported by ARO, TATP and the Robert A. Welch Foundation

  1. Cholesterol-dependent Conformational Plasticity in GPCR Dimers

    PubMed Central

    Prasanna, Xavier; Sengupta, Durba; Chattopadhyay, Amitabha

    2016-01-01

    The organization and function of the serotonin1A receptor, an important member of the GPCR family, have been shown to be cholesterol-dependent, although the molecular mechanism is not clear. We performed a comprehensive structural and dynamic analysis of dimerization of the serotonin1A receptor by coarse-grain molecular dynamics simulations totaling 3.6 ms to explore the molecular details of its cholesterol-dependent association. A major finding is that the plasticity and flexibility of the receptor dimers increase with increased cholesterol concentration. In particular, a dimer interface formed by transmembrane helices I-I was found to be sensitive to cholesterol. The modulation of dimer interface appears to arise from a combination of direct cholesterol occupancy and indirect membrane effects. Interestingly, the presence of cholesterol at the dimer interface is correlated with increased dimer plasticity and flexibility. These results represent an important step in characterizing the molecular interactions in GPCR organization with potential relevance to therapeutic interventions. PMID:27535203

  2. Cholesterol-dependent Conformational Plasticity in GPCR Dimers.

    PubMed

    Prasanna, Xavier; Sengupta, Durba; Chattopadhyay, Amitabha

    2016-01-01

    The organization and function of the serotonin1A receptor, an important member of the GPCR family, have been shown to be cholesterol-dependent, although the molecular mechanism is not clear. We performed a comprehensive structural and dynamic analysis of dimerization of the serotonin1A receptor by coarse-grain molecular dynamics simulations totaling 3.6 ms to explore the molecular details of its cholesterol-dependent association. A major finding is that the plasticity and flexibility of the receptor dimers increase with increased cholesterol concentration. In particular, a dimer interface formed by transmembrane helices I-I was found to be sensitive to cholesterol. The modulation of dimer interface appears to arise from a combination of direct cholesterol occupancy and indirect membrane effects. Interestingly, the presence of cholesterol at the dimer interface is correlated with increased dimer plasticity and flexibility. These results represent an important step in characterizing the molecular interactions in GPCR organization with potential relevance to therapeutic interventions. PMID:27535203

  3. DNA excision repair: where do all the dimers go?

    PubMed

    Kemp, Michael G; Sancar, Aziz

    2012-08-15

    Exposure of cells to UV light from the sun causes the formation of pyrimidine dimers in DNA that have the potential to lead to mutation and cancer. In humans, pyrimidine dimers are removed from the genome in the form of ~30 nt-long oligomers by concerted dual incisions. Though nearly 50 y of excision repair research has uncovered many details of UV photoproduct damage recognition and removal, the fate of the excised oligonucleotides and, in particular, the ultimate fate of the chemically very stable pyrimidine dimers remain unknown. Physiologically relevant UV doses introduce hundreds of thousands of pyrimidine dimers in diploid human cells, which are excised from the genome within ~24 h. Once removed from the genome, "where do all the dimers go?" In a recent study we addressed this question. Although our study did not determine the fate of the dimer itself, it revealed that the excised ~30-mer is released from the duplex in a tight complex with the transcription/repair factor TFIIH. This finding combined with recent reports that base and oligonucleotide products of the base and double-strand break repair pathways also make stable complexes with the cognate repair enzymes, and that these complexes activate the MAP kinase and checkpoint signaling pathways, respectively, raises the possibility that TFIIH-30-mer excision complexes may play a role in signaling reactions in response to UV damage.

  4. Altered Dimer Interface Decreases Stability in an Amyloidogenic Protein

    SciTech Connect

    Baden, Elizabeth M.; Owen, Barbara A.L.; Peterson, Francis C.; Volkman, Brian F.; Ramirez-Alvarado, Marina; Thompson, James R.

    2008-07-21

    Amyloidoses are devastating and currently incurable diseases in which the process of amyloid formation causes fatal cellular and organ damage. The molecular mechanisms underlying amyloidoses are not well known. In this study, we address the structural basis of immunoglobulin light chain amyloidosis, which results from deposition of light chains produced by clonal plasma cells. We compare light chain amyloidosis protein AL-09 to its wild-type counterpart, the kl O18/O8 light chain germline. Crystallographic studies indicate that both proteins form dimers. However, AL-09 has an altered dimer interface that is rotated 90 degrees from the kl O18/O8 dimer interface. The three non-conservative mutations in AL-09 are located within the dimer interface, consistent with their role in the decreased stability of this amyloidogenic protein. Moreover, AL-09 forms amyloid fibrils more quickly than kl O18/O8 in vitro. These results support the notion that the increased stability of the monomer and delayed fibril formation, together with a properly formed dimer, may be protective against amyloidogenesis. This could open a new direction into rational drug design for amyloidogenic proteins.

  5. A comparison of kinetic and regulatory properties of the tetrameric and dimeric forms of wild-type and Thr427-->Pro mutant human phenylalanine hydroxylase: contribution of the flexible hinge region Asp425-Gln429 to the tetramerization and cooperative substrate binding.

    PubMed

    Bjørgo, E; de Carvalho, R M; Flatmark, T

    2001-02-01

    Recombinant human phenylalanine hydroxylase (hPAH, phenylalanine 4-monooxygenase EC 1.14.16.1) is catalytically active both as a tetramer and a dimer [Knappskog, P.M., Flatmark, T., Aarden, J.M., Haavik, J. and Martínez, A. (1996) Eur. J. Biochem. 242, 813-821]. In the present study we have further characterized the differences in kinetic and regulatory properties of the two oligomeric forms when expressed in Escherichia coli. The positive cooperativity of L-Phe binding to the tetrameric form both in enzyme kinetic studies (h = 1.6) and intrinsic tryptophan fluorescence measurements (h = 2.3) was abolished in the dimer, which also revealed a catalytic efficiency (Vmax/[S]0.5) of only 35% of the tetramer. Whereas the catalytic activity of the tetramer was activated fivefold to sixfold by preincubation with L-Phe, the dimer revealed only a 1.6-fold activation. The crystal structure has identified a five-residue flexible hinge region (Asp425-Gln429) that links the beta-strand Tbeta2 (Ile421-Leu424) and the 24 residue amphipathic alpha-helix Talpha1 (Gln428-Lys452) at the C-terminus which forms an antiparallel coiled-coil structure in the center of the tetramer [Fusetti, F., Erlandsen, H., Flatmark, T. & Stevens, R.C. (1998) J. Biol. Chem. 273, 16962-16967]. The potential role of this flexible hinge in the tetramerization and the conformational transition of wt-hPAH on the cooperative binding of L-Phe was examined by site-specific mutagenesis. Substitution of Thr427 by a Pro (as in tyrosine hydroxylase) resulted in a mutant protein which was isolated mainly (about 95%) as a dimer. The isolated tetramer of T427P revealed no kinetic cooperativity of L-Phe binding, the catalytic efficiency (Vmax/[S]0.5) was decreased to about 39% of the wild-type tetramer and it was not activated by L-Phe preincubation. The dimeric forms of T427P and wt-hPAH revealed rather similar kinetic properties. The lack of kinetic cooperativity of the T427P tetramer was associated with a

  6. Lifetime of 6 Li40 K dimers near a Feshbach resonance

    NASA Astrophysics Data System (ADS)

    Jag, Michael; Cetina, Marko; Lous, Rianne; Levinsen, Jesper; Petrov, Dmitry; Grimm, Rudolf

    2016-05-01

    We investigate the lifetime of bosonic dimers formed in a Fermi- Fermi mixture of 6 Li and 40 K atoms near a Feshbach resonance. Pure dimer samples are created from a Li-K mixture by ramping a magnetic field across the resonance and removing unbound atoms. We then perform lifetime measurements using both trapped high-density as well as expanding low-density samples after release from the trap. These measurements discriminate between the spontaneous and the collisional dimer decay. We further determine the dimer decay due to Li-LiK collisions in an atom-dimer mixture. Our measurements reveal a more than three-fold (five-fold) decrease in decay due to dimer-dimer (atom-dimer) collisions as the Feshbach resonance is approached. This observation is in good agreement with a theoretical prediction, which relates the decay rate to the probability of finding the colliding atoms within a short distance, and can mostly be explained by the increased fermionic character of the halo-dimer state together with Pauli blocking. We apply our model to combinations of other fermionic species to predict the dimer lifetime, which is an important parameter for their prospect towards realizing novel quantum phases. SFB FoQuS.

  7. The Ammonia Dimer Revisited

    NASA Astrophysics Data System (ADS)

    Dawes, Richard; Van Der Avoird, Ad

    2012-06-01

    The conclusion from microwave spectra by Nelson, Fraser, and Klemperer that the ammonia dimer has a nearly cyclic structure led to much debate about the issue of whether (NH_3)_2 is hydrogen bonded. This structure was surprising because most {ab initio} calculations led to a classical, nearly linear, hydrogen-bonded structure. An obvious explanation of the discrepancy between the outcome of these calculations and the microwave data which led Nelson {et al.} to their ``surprising structure'' might be the effect of vibrational averaging: the electronic structure calculations focus on finding the minimum of the intermolecular potential, the experiment gives a vibrationally averaged structure. Isotope substitution studies seemed to indicate, however, that the complex is nearly rigid. Additional data became available from high-resolution molecular beam far-infrared spectroscopy in the Saykally group. These spectra, displaying large tunneling splittings, indicate that the complex is very floppy. The seemingly contradictory experimental data were explained when it became possible to calculate the vibration-rotation-tunneling (VRT) states of the complex on a six-dimensional intermolecular potential surface. The potential used was a simple model potential, with parameters fitted to the far-infrared data. Now, for the first time, a six-dimensional potential was computed by high level {ab initio} methods and this potential will be used in calculations of the VRT states of (NH_3)_2 and (ND_3)_2. So, we will finally be able to answer the question whether the conclusions from the model calculations are indeed a valid explanation of the experimental data. D. Nelson, G. T. Fraser, and W. Klemperer J. Chem. Phys. 83 6201 (1985) J. G. Loeser, C. A. Schmuttenmaer, R. C. Cohen, M. J. Elrod, D. W. Steyert, R. J. Saykally, R. E. Bumgarner, and G. A. Blake J. Chem. Phys. 97 4727 (1992) E. H. T. Olthof, A. van der Avoird, and P. E. S. Wormer J. Chem. Phys. 101 8430 (1994) E. H. T. Olthof

  8. Radiation-induced tetramer-to-dimer transition of Escherichia coli lactose repressor

    SciTech Connect

    Goffinont, S.; Davidkova, M.

    2009-08-21

    The wild type lactose repressor of Escherichia coli is a tetrameric protein formed by two identical dimers. They are associated via a C-terminal 4-helix bundle (called tetramerization domain) whose stability is ensured by the interaction of leucine zipper motifs. Upon in vitro {gamma}-irradiation the repressor losses its ability to bind the operator DNA sequence due to damage of its DNA-binding domains. Using an engineered dimeric repressor for comparison, we show here that irradiation induces also the change of repressor oligomerisation state from tetramer to dimer. The splitting of the tetramer into dimers can result from the oxidation of the leucine residues of the tetramerization domain.

  9. Regioisomeric allene dimer formation by the reaction of tetraarylbutatrienes with tetracyanoethene.

    PubMed

    Ueta, Shoko; Hida, Kazuo; Nishiuchi, Masaki; Kawamura, Yasuhiko

    2014-05-01

    The reaction of tetraarylbutatrienes (tetraaryl[3]cumulenes) with tetracyanoethene (TCNE), a strong electron-accepting molecule, at room temperature yielded novel four-membered ring compounds (head-to-tail unsymmetrically substituted diarylallene dimers) by [2 + 2] cycloaddition of the central C=C bond of the butatrienes. This reaction proceeded through a head-to-head symmetrically substituted diarylallene dimer intermediate. Unsymmetrical butatriene also formed a small amount of another head-to-tail dimer. Although the allene dimer is stable in nonpolar solvents, it converts to other bicyclic and tricyclic compounds in MeOH or CH3CN at room temperature.

  10. Thiazole Orange Dimers in DNA: Fluorescent Base Substitutions with Hybridization Readout.

    PubMed

    Berndl, Sina; Dimitrov, Stoichko D; Menacher, Florian; Fiebig, Torsten; Wagenknecht, Hans-Achim

    2016-02-12

    By using (S)-2-amino-1,3-propanediol as a linker, thiazole orange (TO) was incorporated in a dimeric form into DNA. The green fluorescence (λ=530 nm) of the intrastrand TO dimer is quenched, whereas the interstrand TO dimer shows a characteristic redshifted orange emission (λ=585 nm). Steady-state optical spectroscopic methods reveal that the TO dimer fluorescence is independent of the sequential base contexts. Time-resolved pump-probe measurements and excitation spectra reveal the coexistence of conformations, including mainly stacked TO dimers and partially unstacked ones, which yield exciton and excimer contributions to the fluorescence, respectively. The helicity of the DNA framework distorts the excitonic coupling. In particular, the interstrand TO dimer could be regarded as an excitonically interacting base pair with fluorescence readout for DNA hybridization. Finally, the use of this fluorescent readout was representatively demonstrated in molecular beacons.

  11. Structure of acetylcholine receptor dimer determined by neutron scattering and electron microscopy

    SciTech Connect

    Wise, D.S.; Schoenborn, B.P.; Karlin, A.

    1981-04-10

    Previous work has shown that the predominant native form of the acetylcholine receptor from the electric tissue of Torpedo californica is a dimer of M/sub r/ = 500,000, cross-linked by a disulfide bond between the largest (delta) of the five chains (..cap alpha../sub 2/..beta gamma..delta) that comprise the monomer. Small-angle neutron scattering of purified receptor dimer in Triton X-100 solution containing 18% D/sub 2/O, in which the Triton X-100 is contrast-matched, yields a radius of gyration of the dimer of 66 A. Based on the assumptions that the dimer is symmetrical and that the radius of gyration of the monomer does not change in forming dimer, this value, together with the radius of gyration of the receptor monomer (46 A), determined previously, allows the calculation of the distance separating the centers of neutron scattering density of monomers in a dimer; the result is 96 A. Electron microscopy of negatively stained dimers permits an independent measurement of the distance between the apparent centers of mass of the monomers; the average is 96 A, in agreement with the result of the neutron scattering analysis. The electron micrographs of dimer also permit the location of the delta chains at the region of contact of the monomers. A model for the receptor dimer consistent with all available structural information is presented.

  12. Effects of Dimerization of Serratia marcescens Endonuclease on Water Dynamics.

    SciTech Connect

    Chen, Chuanying; Beck, Brian W.; Krause, Kurt; Weksberg, Tiffany E.; Pettitt, Bernard M.

    2007-02-15

    The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. The dynamics and structure of Serratia marcescens endonuclease and its neighboring solvent are investigated by molecular dynamics (MD). Comparisons are made with structural and biochemical experiments. The dimer form is physiologic and functions more processively than the monomer. We previously found a channel formed by connected clusters of waters from the active site to the dimer interface. Here, we show that dimerization clearly changes correlations in the water structure and dynamics in the active site not seen in the monomer. Our results indicate that water at the active sites of the dimer is less affected compared with bulk solvent than in the monomer where it has much slower characteristic relaxation times. Given that water is a required participant in the reaction, this gives a clear advantage to dimerization in the absence of an apparent ability to use both active sites simultaneously.

  13. Adventures in Holographic Dimer Models

    SciTech Connect

    Kachru, Shamit; Karch, Andreas; Yaida, Sho; /Stanford U., Phys. Dept.

    2011-08-12

    We abstract the essential features of holographic dimer models, and develop several new applications of these models. Firstly, semi-holographically coupling free band fermions to holographic dimers, we uncover novel phase transitions between conventional Fermi liquids and non-Fermi liquids, accompanied by a change in the structure of the Fermi surface. Secondly, we make dimer vibrations propagate through the whole crystal by way of double trace deformations, obtaining nontrivial band structure. In a simple toy model, the topology of the band structure experiences an interesting reorganization as we vary the strength of the double trace deformations. Finally, we develop tools that would allow one to build, in a bottom-up fashion, a holographic avatar of the Hubbard model.

  14. Benchmarking of Optical Dimerizer Systems

    PubMed Central

    2015-01-01

    Optical dimerizers are a powerful new class of optogenetic tools that allow light-inducible control of protein–protein interactions. Such tools have been useful for regulating cellular pathways and processes with high spatiotemporal resolution in live cells, and a growing number of dimerizer systems are available. As these systems have been characterized by different groups using different methods, it has been difficult for users to compare their properties. Here, we set about to systematically benchmark the properties of four optical dimerizer systems, CRY2/CIB1, TULIPs, phyB/PIF3, and phyB/PIF6. Using a yeast transcriptional assay, we find significant differences in light sensitivity and fold-activation levels between the red light regulated systems but similar responses between the CRY2/CIB and TULIP systems. Further comparison of the ability of the CRY2/CIB1 and TULIP systems to regulate a yeast MAPK signaling pathway also showed similar responses, with slightly less background activity in the dark observed with CRY2/CIB. In the process of developing this work, we also generated an improved blue-light-regulated transcriptional system using CRY2/CIB in yeast. In addition, we demonstrate successful application of the CRY2/CIB dimerizers using a membrane-tethered CRY2, which may allow for better local control of protein interactions. Taken together, this work allows for a better understanding of the capacities of these different dimerization systems and demonstrates new uses of these dimerizers to control signaling and transcription in yeast. PMID:25350266

  15. Benchmarking of optical dimerizer systems.

    PubMed

    Pathak, Gopal P; Strickland, Devin; Vrana, Justin D; Tucker, Chandra L

    2014-11-21

    Optical dimerizers are a powerful new class of optogenetic tools that allow light-inducible control of protein-protein interactions. Such tools have been useful for regulating cellular pathways and processes with high spatiotemporal resolution in live cells, and a growing number of dimerizer systems are available. As these systems have been characterized by different groups using different methods, it has been difficult for users to compare their properties. Here, we set about to systematically benchmark the properties of four optical dimerizer systems, CRY2/CIB1, TULIPs, phyB/PIF3, and phyB/PIF6. Using a yeast transcriptional assay, we find significant differences in light sensitivity and fold-activation levels between the red light regulated systems but similar responses between the CRY2/CIB and TULIP systems. Further comparison of the ability of the CRY2/CIB1 and TULIP systems to regulate a yeast MAPK signaling pathway also showed similar responses, with slightly less background activity in the dark observed with CRY2/CIB. In the process of developing this work, we also generated an improved blue-light-regulated transcriptional system using CRY2/CIB in yeast. In addition, we demonstrate successful application of the CRY2/CIB dimerizers using a membrane-tethered CRY2, which may allow for better local control of protein interactions. Taken together, this work allows for a better understanding of the capacities of these different dimerization systems and demonstrates new uses of these dimerizers to control signaling and transcription in yeast. PMID:25350266

  16. DNA melting properties of the dityrosine cross-linked dimer of Ribonuclease A.

    PubMed

    Dinda, Amit Kumar; Chattaraj, Saparya; Ghosh, Sudeshna; Tripathy, Debi Ranjan; Dasgupta, Swagata

    2016-09-01

    Several DNA binding proteins exist in dimeric form when bound with DNA to be able to exhibit various biological processes such as DNA repair, DNA replication and gene expression. Various dimeric