151
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Pires AS, Porto WF, Franco OL, Alencar SA. In silico analyses of deleterious missense SNPs of human apolipoprotein E3. Sci Rep 2017; 7:2509. [PMID: 28559539 PMCID: PMC5449402 DOI: 10.1038/s41598-017-01737-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 03/27/2017] [Indexed: 12/23/2022] Open
Abstract
ApoE3 is the major chylomicron apolipoprotein, binding in a specific liver peripheral cell receptor, allowing transport and normal catabolism of triglyceride-rich lipoprotein constituents. Point mutations in ApoE3 have been associated with Alzheimer's disease, type III hyperlipoproteinemia, atherosclerosis, telomere shortening and impaired cognitive function. Here, we evaluate the impact of missense SNPs in APOE retrieved from dbSNP through 16 computational prediction tools, and further evaluate the structural impact of convergent deleterious changes using 100 ns molecular dynamics simulations. We have found structural changes in four analyzed variants (Pro102Arg, Arg132Ser, Arg176Cys and Trp294Cys), two of them (Pro102Arg and Arg176Cys) being previously associated with human diseases. In all cases, except for Trp294Cys, there was a loss in the number of hydrogen bonds between CT and NT domains that could result in their detachment. In conclusion, data presented here could increase the knowledge of ApoE3 activity and be a starting point for the study of the impact of variations on APOE gene.
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Affiliation(s)
- Allan S Pires
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil
- Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil
| | - William F Porto
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil
- Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil
- Porto Reports, Brasília-DF, Brazil
| | - Octavio L Franco
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil
- Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil
- S-Inova Biotech, Pós-graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil
| | - Sérgio A Alencar
- Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF, Brazil.
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152
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Crouchet E, Lefèvre M, Verrier ER, Oudot MA, Baumert TF, Schuster C. Extracellular lipid-free apolipoprotein E inhibits HCV replication and induces ABCG1-dependent cholesterol efflux. Gut 2017; 66:896-907. [PMID: 27609828 PMCID: PMC5531222 DOI: 10.1136/gutjnl-2015-311289] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 07/13/2016] [Accepted: 07/30/2016] [Indexed: 12/21/2022]
Abstract
OBJECTIVE The HCV life cycle and the lipid metabolism are inextricably intertwined. In the blood, HCV virions are associated with lipoproteins, forming lipoviroparticles (LVPs), which are the most infectious form of the virus. Apolipoprotein E (apoE), a key LVP component, plays an essential role in HCV entry, assembly and egress. ApoE is also a cell host factor involved in lipoprotein homeostasis. Although the majority of apoE is associated with lipoproteins, a lipid-free (LF) form exists in blood. However, the role of LF-apoE in both lipid metabolism and HCV life cycle is poorly understood. DESIGN In this study, using the cell culture-derived HCV model system in human hepatoma Huh7.5.1 cells and primary human hepatocytes (PHH), we investigated the effect of LF-apoE on the early steps of HCV life cycle and on the lipid metabolism of hepatic cells. RESULTS A dose-dependent decrease in HCV replication was observed when Huh7.5.1 cells and PHH were treated with increasing amounts of LF-apoE. We showed that LF-apoE acts on HCV replication independently of previously described apoE receptors. We observed that LF-apoE induced a marked hepatic cholesterol efflux via the ATP-binding cassette subfamily G member 1 (ABCG1) protein that in turn inhibits HCV replication. LF-apoE also increases both apolipoprotein AI and high-density lipoprotein production. CONCLUSIONS Our findings highlight a new mechanism in lipid metabolism regulation and interaction of the lipid metabolism with the HCV life cycle, which may be important for viral pathogenesis and might also be explored for antiviral therapy.
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Affiliation(s)
- Emilie Crouchet
- INSERM, UMR_S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France,Université de Strasbourg, Strasbourg, France
| | - Mathieu Lefèvre
- INSERM, UMR_S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France,Université de Strasbourg, Strasbourg, France
| | - Eloi R Verrier
- INSERM, UMR_S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France,Université de Strasbourg, Strasbourg, France
| | - Marine A Oudot
- INSERM, UMR_S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France,Université de Strasbourg, Strasbourg, France
| | - Thomas F Baumert
- INSERM, UMR_S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France,Université de Strasbourg, Strasbourg, France,Institut Hopitalo-Universitaire, Pôle hépato-digestif, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Catherine Schuster
- INSERM, UMR_S1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France,Université de Strasbourg, Strasbourg, France
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153
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Horn JVC, Ellena RA, Tran JJ, Beck WHJ, Narayanaswami V, Weers PMM. Transfer of C-terminal residues of human apolipoprotein A-I to insect apolipophorin III creates a two-domain chimeric protein with enhanced lipid binding activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1317-1325. [PMID: 28434970 DOI: 10.1016/j.bbamem.2017.04.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/14/2017] [Accepted: 04/19/2017] [Indexed: 01/11/2023]
Abstract
Apolipophorin III (apoLp-III) is an insect apolipoprotein (18kDa) that comprises a single five-helix bundle domain. In contrast, human apolipoprotein A-I (apoA-I) is a 28kDa two-domain protein: an α-helical N-terminal domain (residues 1-189) and a less structured C-terminal domain (residues 190-243). To better understand the apolipoprotein domain organization, a novel chimeric protein was engineered by attaching residues 179 to 243 of apoA-I to the C-terminal end of apoLp-III. The apoLp-III/apoA-I chimera was successfully expressed and purified in E. coli. Western blot analysis and mass spectrometry confirmed the presence of the C-terminal domain of apoA-I within the chimera. While parent apoLp-III did not self-associate, the chimera formed oligomers similar to apoA-I. The chimera displayed a lower α-helical content, but the stability remained similar compared to apoLp-III, consistent with the addition of a less structured domain. The chimera was able to solubilize phospholipid vesicles at a significantly higher rate compared to apoLp-III, approaching that of apoA-I. The chimera was more effective in protecting phospholipase C-treated low density lipoprotein from aggregation compared to apoLp-III. In addition, binding interaction of the chimera with phosphatidylglycerol vesicles and lipopolysaccharides was considerably improved compared to apoLp-III. Thus, addition of the C-terminal domain of apoA-I to apoLp-III created a two-domain protein, with self-association, lipid and lipopolysaccharide binding properties similar to apoA-I. The apoA-I like behavior of the chimera indicate that these properties are independent from residues residing in the N-terminal domain of apoA-I, and that they can be transferred from apoA-I to apoLp-III.
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Affiliation(s)
- James V C Horn
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, CA 90840, United States
| | - Rachel A Ellena
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, CA 90840, United States
| | - Jesse J Tran
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, CA 90840, United States
| | - Wendy H J Beck
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, CA 90840, United States
| | - Vasanthy Narayanaswami
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, CA 90840, United States
| | - Paul M M Weers
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, CA 90840, United States.
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154
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Jendresen C, Årskog V, Daws MR, Nilsson LNG. The Alzheimer's disease risk factors apolipoprotein E and TREM2 are linked in a receptor signaling pathway. J Neuroinflammation 2017; 14:59. [PMID: 28320424 PMCID: PMC5360024 DOI: 10.1186/s12974-017-0835-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 03/07/2017] [Indexed: 11/19/2022] Open
Abstract
Background Triggering receptor expressed on myeloid cells 2 (TREM2) and apolipoprotein E (APOE) are genetically linked to Alzheimer’s disease. Here, we investigated whether human ApoE mediates signal transduction through human and murine TREM2 and sought to identify a TREM2-binding domain in human ApoE. Methods To investigate cell signaling through TREM2, a cell line was used which expressed an NFAT-inducible β-galactosidase reporter and human or murine TREM2, fused to CD8 transmembrane and CD3ζ intracellular signaling domains. ELISA-based binding assays were used to determine binding affinities of human ApoE isoforms to human TREM2 and to identify a TREM2-binding domain in ApoE. Results ApoE was found to be an agonist to human TREM2 with EC50 in the low nM range, and to murine TREM2 with reduced potency. In the reporter cells, TREM2 expression was lower than in nontransgenic mouse brain. Human ApoE isoforms ε2, ε3, and ε4 bound to human TREM2 with Kd in the low nM range. The binding was displaced by an ApoE-mimetic peptide (amino acids 130–149). Conclusions An ApoE-mediated dose-dependent signal transduction through TREM2 in reporter cells was demonstrated, and a TREM2-binding region in ApoE was identified. The relevance of an ApoE-TREM2 receptor signaling pathway to Alzheimer’s disease is discussed. Electronic supplementary material The online version of this article (doi:10.1186/s12974-017-0835-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Charlotte Jendresen
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Postboks 1057 Blindern, 0316, Oslo, Norway
| | - Vibeke Årskog
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Postboks 1057 Blindern, 0316, Oslo, Norway
| | - Michael R Daws
- Division of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Lars N G Nilsson
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Postboks 1057 Blindern, 0316, Oslo, Norway.
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155
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Apolipoprotein E: the resilience gene. Exp Brain Res 2017; 235:1853-1859. [DOI: 10.1007/s00221-017-4941-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/02/2017] [Indexed: 02/07/2023]
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156
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A randomized trial and novel SPR technique identifies altered lipoprotein-LDL receptor binding as a mechanism underlying elevated LDL-cholesterol in APOE4s. Sci Rep 2017; 7:44119. [PMID: 28276521 PMCID: PMC5343425 DOI: 10.1038/srep44119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 02/03/2017] [Indexed: 11/10/2022] Open
Abstract
At a population level APOE4 carriers (~25% Caucasians) are at higher risk of cardiovascular diseases. The penetrance of genotype is however variable and influenced by dietary fat composition, with the APOE4 allele associated with greater LDL-cholesterol elevation in response to saturated fatty acids (SFA). The etiology of this greater responsiveness is unknown. Here a novel surface plasmon resonance technique (SPR) is developed and used, along with hepatocyte (with the liver being the main organ modulating lipoprotein metabolism and plasma lipid levels) uptake studies to establish the impact of dietary fatty acid composition on, lipoprotein-LDL receptor (LDLR) binding, and hepatocyte uptake, according to APOE genotype status. In men prospectively recruited according to APOE genotype (APOE3/3 common genotype, or APOE3/E4), triglyceride-rich lipoproteins (TRLs) were isolated at fasting and 4–6 h following test meals rich in SFA, unsaturated fat and SFA with fish oil. In APOE4s a greater LDLR binding affinity of postprandial TRL after SFA, and lower LDL binding and hepatocyte internalization, provide mechanisms for the greater LDL-cholesterol raising effect. The SPR technique developed may be used for the future study of the impact of genotype, and physiological and behavioral variables on lipoprotein metabolism. Trial registration number NCT01522482.
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157
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Pate KM, Murphy RM. Cerebrospinal Fluid Proteins as Regulators of Beta-amyloid Aggregation and Toxicity. Isr J Chem 2017; 57:602-612. [PMID: 29129937 DOI: 10.1002/ijch.201600078] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Amyloid disorders, such as Alzheimer's, are almost invariably late-onset diseases. One defining diagnostic feature of Alzheimer's disease is the deposition of beta-amyloid as extracellular plaques, primarily in the hippocampus. This raises the question: are there natural protective agents that prevent beta-amyloid from depositing, and is it loss of this protection that leads to onset of disease? Proteins in cerebrospinal fluid (CSF) have been suggested to act as just such natural protective agents. Here, we describe some of the early evidence that led to this suggestion, and we discuss, in greater detail, two CSF proteins that have garnered the bulk of the attention.
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Affiliation(s)
- Kayla M Pate
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison WI 53706 (USA)
| | - Regina M Murphy
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison WI 53706 (USA)
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158
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Recio C, Maione F, Iqbal AJ, Mascolo N, De Feo V. The Potential Therapeutic Application of Peptides and Peptidomimetics in Cardiovascular Disease. Front Pharmacol 2017; 7:526. [PMID: 28111551 PMCID: PMC5216031 DOI: 10.3389/fphar.2016.00526] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 12/19/2016] [Indexed: 12/11/2022] Open
Abstract
Cardiovascular disease (CVD) remains a leading cause of mortality and morbidity worldwide. Numerous therapies are currently under investigation to improve pathological cardiovascular complications, but yet, there have been very few new medications approved for intervention/treatment. Therefore, new approaches to treat CVD are urgently required. Attempts to prevent vascular complications usually involve amelioration of contributing risk factors and underlying processes such as inflammation, obesity, hyperglycaemia, or hypercholesterolemia. Historically, the development of peptides as therapeutic agents has been avoided by the Pharmaceutical industry due to their low stability, size, rate of degradation, and poor delivery. However, more recently, resurgence has taken place in developing peptides and their mimetics for therapeutic intervention. As a result, increased attention has been placed upon using peptides that mimic the function of mediators involved in pathologic processes during vascular damage. This review will provide an overview on novel targets and experimental therapeutic approaches based on peptidomimetics for modulation in CVD. We aim to specifically examine apolipoprotein A-I (apoA-I) and apoE mimetic peptides and their role in cholesterol transport during atherosclerosis, suppressors of cytokine signaling (SOCS)1-derived peptides and annexin-A1 as potent inhibitors of inflammation, incretin mimetics and their function in glucose-insulin tolerance, among others. With improvements in technology and synthesis platforms the future looks promising for the development of novel peptides and mimetics for therapeutic use. However, within the area of CVD much more work is required to identify and improve our understanding of peptide structure, interaction, and function in order to select the best targets to take forward for treatment.
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Affiliation(s)
- Carlota Recio
- Sir William Dunn School of Pathology, University of Oxford Oxford, UK
| | - Francesco Maione
- Department of Pharmacy, University of Naples Federico II Naples, Italy
| | - Asif J Iqbal
- Sir William Dunn School of Pathology, University of Oxford Oxford, UK
| | - Nicola Mascolo
- Department of Pharmacy, University of Naples Federico II Naples, Italy
| | - Vincenzo De Feo
- Department of Pharmacy, University of Salerno Salerno, Italy
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159
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Weller R, Todt D, Engelmann M, Friesland M, Wedemeyer H, Pietschmann T, Steinmann E. Apolipoprotein E polymorphisms and their protective effect on hepatitis E virus replication. Hepatology 2016; 64:2274-2276. [PMID: 27541341 DOI: 10.1002/hep.28788] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Romy Weller
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research GmbH; a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Daniel Todt
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research GmbH; a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Michael Engelmann
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research GmbH; a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Martina Friesland
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research GmbH; a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Heiner Wedemeyer
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany.,German Center for Infectious Disease Research (DZIF), Partner Site Hannover-Braunschweig, Braunschweig, Germany
| | - Thomas Pietschmann
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research GmbH; a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Eike Steinmann
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research GmbH; a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
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160
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Shabanzadeh DM, Sørensen LT, Jørgensen T. Gallstone disease and mortality: a cohort study. Int J Public Health 2016; 62:353-360. [DOI: 10.1007/s00038-016-0916-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/21/2016] [Accepted: 10/22/2016] [Indexed: 12/12/2022] Open
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161
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The Complex Role of Apolipoprotein E in Alzheimer's Disease: an Overview and Update. J Mol Neurosci 2016; 60:325-335. [PMID: 27647307 DOI: 10.1007/s12031-016-0839-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/05/2016] [Indexed: 10/21/2022]
Abstract
Apolipoprotein E (ApoE) plays a crucial role in the homeostatic control of lipids in both the periphery and the central nervous system (CNS). In humans, ApoE exists in three different isoforms: ε2, ε3 and ε4. ApoE ε3 is the most common isoform, while the ε4 isoform confers the greatest genetic risk for Alzheimer's disease (AD). However, the mechanisms underlying how ApoE contributes to the pathogenesis of AD are still debated. ApoE has been shown to impact amyloid β (Aβ) deposition and clearance in the brain. ApoE also has Aβ-independent pathways in AD, which has led to the discovery of new roles of ApoE ranging from mitochondria dysfunction to, most recently, iron metabolism. Here, we review the role of ApoE in health and in AD, with the view of identifying therapeutic approaches that could prevent the risk associated with the ε4 isoform.
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162
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Human Cathelicidin Compensates for the Role of Apolipoproteins in Hepatitis C Virus Infectious Particle Formation. J Virol 2016; 90:8464-77. [PMID: 27440892 DOI: 10.1128/jvi.00471-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 07/05/2016] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED Exchangeable apolipoproteins (ApoA, -C, and -E) have been shown to redundantly participate in the formation of infectious hepatitis C virus (HCV) particles during the assembly process, although their precise role in the viral life cycle is not well understood. Recently, it was shown that the exogenous expression of only short sequences containing amphipathic α-helices from various apolipoproteins is sufficient to restore the formation of infectious HCV particles in ApoB and ApoE double-gene-knockout Huh7 (BE-KO) cells. In this study, through the expression of a small library of human secretory proteins containing amphipathic α-helix structures, we identified the human cathelicidin antimicrobial peptide (CAMP), the only known member of the cathelicidin family of antimicrobial peptides (AMPs) in humans and expressed mainly in bone marrow and leukocytes. We showed that CAMP is able to rescue HCV infectious particle formation in BE-KO cells. In addition, we revealed that the LL-37 domain in CAMP containing amphipathic α-helices is crucial for the compensation of infectivity in BE-KO cells, and the expression of CAMP in nonhepatic 293T cells expressing claudin 1 and microRNA miR-122 confers complete propagation of HCV. These results suggest the possibility of extrahepatic propagation of HCV in cells with low-level or no expression of apolipoproteins but expressing secretory proteins containing amphipathic α-helices such as CAMP. IMPORTANCE Various exchangeable apolipoproteins play a pivotal role in the formation of infectious HCV during the assembly of viral particles, and amphipathic α-helix motifs in the apolipoproteins have been shown to be a key factor. To the best of our knowledge, we have identified for the first time the human cathelicidin CAMP as a cellular protein that can compensate for the role of apolipoproteins in the life cycle of HCV. We have also identified the domain in CAMP that contains amphipathic α-helices crucial for compensation and show that the expression of CAMP in nonhepatic cells expressing claudin 1 and miR-122 confers complete propagation of HCV. We speculate that low levels of HCV propagation might be possible in extrahepatic tissues expressing secretory proteins containing amphipathic α-helices without the expression of apolipoproteins.
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163
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Apolipoprotein E4: A Risk Factor for Successful Cognitive Aging. Dement Neurocogn Disord 2016; 15:61-67. [PMID: 30906344 PMCID: PMC6427966 DOI: 10.12779/dnd.2016.15.3.61] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 09/29/2016] [Accepted: 09/29/2016] [Indexed: 11/27/2022] Open
Abstract
Apolipoprotein E is a plasma protein that has an important role in transport and metabolism of lipids in serum as well as central nervous system. Among the 3 common alleles, the ε2 allele has the most stable structure followed by ε3 and ε4 in order. There is evidence for a deleterious role of ε4 allele by atherosclerosis and amyloid beta accumulation in brain and body. The presence and gene dose of ε4 allele are risk factors for late-onset Alzheimer's disease. Apolipoprotein E ε4 may have a role in the pathology of amyloid beta and tau and it has a strong relationship with the early onset of late-onset Alzheimer's disease. However, early-onset Alzheimer's disease has a weaker relationship with ε4 allele of apolipoprotein E.
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164
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Yamazaki Y, Painter MM, Bu G, Kanekiyo T. Apolipoprotein E as a Therapeutic Target in Alzheimer's Disease: A Review of Basic Research and Clinical Evidence. CNS Drugs 2016; 30:773-89. [PMID: 27328687 PMCID: PMC5526196 DOI: 10.1007/s40263-016-0361-4] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
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.
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Affiliation(s)
- Yu Yamazaki
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA
| | - Meghan M Painter
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA
| | - Takahisa Kanekiyo
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL, 32224, USA.
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165
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The ability of apolipoprotein E fragments to promote intraneuronal accumulation of amyloid beta peptide 42 is both isoform and size-specific. Sci Rep 2016; 6:30654. [PMID: 27476701 PMCID: PMC4967930 DOI: 10.1038/srep30654] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 07/07/2016] [Indexed: 11/15/2022] Open
Abstract
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.
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166
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Blum CB. Type III Hyperlipoproteinemia: Still Worth Considering? Prog Cardiovasc Dis 2016; 59:119-124. [PMID: 27481046 DOI: 10.1016/j.pcad.2016.07.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 07/28/2016] [Indexed: 01/06/2023]
Abstract
Familial type III hyperlipoproteinemia (HLP) was first recognized as a distinct entity over 60 years ago. Since then, it has proven to be instructive in identifying the key role of apolipoprotein E (apoE) in removal of the remnants of very low density lipoproteins and chylomicrons produced by the action of lipoprotein lipase on these triglyceride-transporting lipoproteins. It has additionally shed light on the potent atherogenicity of the remnant lipoproteins. This review describes the history of development of our understanding of type III HLP, discusses the several genetic variants of apoE that play roles in the genesis of type III HLP, and describes the remarkable responsiveness of this fascinating disorder to lifestyle modification, especially carbohydrate restriction and calorie restriction, and, when required, the addition of pharmacotherapy.
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Affiliation(s)
- Conrad B Blum
- Columbia University College of Physicians and Surgeons, New York, NY 10019, USA.
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Dose J, Huebbe P, Nebel A, Rimbach G. APOE genotype and stress response - a mini review. Lipids Health Dis 2016; 15:121. [PMID: 27457486 PMCID: PMC4960866 DOI: 10.1186/s12944-016-0288-2] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 07/12/2016] [Indexed: 12/31/2022] Open
Abstract
The APOE gene is one of currently only two genes that have consistently been associated with longevity. Apolipoprotein E (APOE) is a plasma protein which plays an important role in lipid and lipoprotein metabolism. In humans, there are three major APOE isoforms, designated APOE2, APOE3, and APOE4. Of these three isoforms, APOE3 is most common while APOE4 was shown to be associated with age-related diseases, including cardiovascular and Alzheimer’s disease, and therefore an increased mortality risk with advanced age. Evidence accumulates, showing that oxidative stress and, correspondingly, mitochondrial function is affected in an APOE isoform-dependent manner. Accordingly, several stress response pathways implicated in the aging process, including the endoplasmic reticulum stress response and immune function, appear to be influenced by the APOE genotype. The investigation and development of treatment strategies targeting APOE4 have not resolved any therapeutic yet that could be entirely recommended. This mini-review provides an overview on the state of research concerning the impact of the APOE genotype on stress response-related processes, emphasizing the strong interconnection between mitochondrial function, endoplasmic reticulum stress and the immune response. Furthermore, this review addresses potential treatment strategies and associated pitfalls as well as lifestyle interventions that could benefit people with an at risk APOE4 genotype.
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Affiliation(s)
- Janina Dose
- Institute of Human Nutrition and Food Science, Kiel University, Hermann-Rodewald-Str. 6, D-24118, Kiel, Germany. .,Institute of Clinical Molecular Biology, Kiel University, Schittenhelmstr. 12, D-24105, Kiel, Germany.
| | - Patricia Huebbe
- Institute of Human Nutrition and Food Science, Kiel University, Hermann-Rodewald-Str. 6, D-24118, Kiel, Germany
| | - Almut Nebel
- Institute of Clinical Molecular Biology, Kiel University, Schittenhelmstr. 12, D-24105, Kiel, Germany
| | - Gerald Rimbach
- Institute of Human Nutrition and Food Science, Kiel University, Hermann-Rodewald-Str. 6, D-24118, Kiel, Germany
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168
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Dose J, Nebel A, Piegholdt S, Rimbach G, Huebbe P. Influence of the APOE genotype on hepatic stress response: Studies in APOE targeted replacement mice and human liver cells. Free Radic Biol Med 2016; 96:264-72. [PMID: 27130033 DOI: 10.1016/j.freeradbiomed.2016.04.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/22/2016] [Accepted: 04/25/2016] [Indexed: 11/29/2022]
Abstract
Apolipoprotein E (APOE) is a multifunctional plasma protein mainly acting in lipid metabolism. Human APOE is polymorphic with three major isoforms (APOE2, APOE3 and APOE4). Up to 75% of the body's APOE is produced by the liver. There is increasing evidence from studies in brain-derived cells that APOE4 affects mitochondrial function and biogenesis as well as stress and inflammatory responses - processes, whose disturbances are considered hallmarks of the ageing process. However, although the liver is the main production site of APOE, knowledge about the impact of the APOE genotype on hepatic stress response-related processes is rather limited. Therefore, we studied biomarkers of oxidative status (glutathione levels, 3-nitrotyrosine adducts, protein carbonyl concentration), ER stress (XBP1(S), BiP, DDIT3), proteasome activity, mitochondrial function (respiratory complexes, ATP levels and mitochondrial membrane potential as well as biomarkers of mitochondrial biogenesis, fission and fusion), autophagy (LC3, LAMP2A), apoptosis (BCL2, BAX, CYCS) and DNA damage in the liver of APOE targeted replacement (TR) mice and in Huh7 hepatocytes overexpressing the APOE3 and the APOE4 isoform, respectively. APOE4 mice exhibited a lower chymotrypsin-like and a higher trypsin-like proteasome activity. Levels of protein carbonyls were moderately higher in liver tissue of APOE4 vs. APOE3 mice. Other biomarkers of oxidative stress were similar between the two genotypes. Under basal conditions, the stress-response pathways investigated appeared largely unaffected by the APOE genotype. However, upon stress induction, APOE4 expressing cells showed lower levels of adenosine triphosphate (ATP) and lower mRNA levels of the ATP-generating complex V of the mitochondrial respiratory chain. Overall, our findings provide evidence for a rather low influence of the APOE genotype on the hepatic stress response processes investigated in this study.
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Affiliation(s)
- Janina Dose
- Institute of Human Nutrition and Food Science, University of Kiel, Hermann-Rodewald-Str. 6, 24118 Kiel, Germany.
| | - Almut Nebel
- Institute of Clinical Molecular Biology, University of Kiel, University Hospital Schleswig-Holstein, Schittenhelmstr. 12, 24105 Kiel, Germany.
| | - Stefanie Piegholdt
- Institute of Human Nutrition and Food Science, University of Kiel, Hermann-Rodewald-Str. 6, 24118 Kiel, Germany.
| | - Gerald Rimbach
- Institute of Human Nutrition and Food Science, University of Kiel, Hermann-Rodewald-Str. 6, 24118 Kiel, Germany.
| | - Patricia Huebbe
- Institute of Human Nutrition and Food Science, University of Kiel, Hermann-Rodewald-Str. 6, 24118 Kiel, Germany.
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Abstract
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.
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170
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Ganesh HV, Chow AM, Kerman K. Recent advances in biosensors for neurodegenerative disease detection. Trends Analyt Chem 2016. [DOI: 10.1016/j.trac.2016.02.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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171
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Zhao L, Gottesdiener AJ, Parmar M, Li M, Kaminsky SM, Chiuchiolo MJ, Sondhi D, Sullivan PM, Holtzman DM, Crystal RG, Paul SM. Intracerebral adeno-associated virus gene delivery of apolipoprotein E2 markedly reduces brain amyloid pathology in Alzheimer's disease mouse models. Neurobiol Aging 2016; 44:159-172. [PMID: 27318144 DOI: 10.1016/j.neurobiolaging.2016.04.020] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Revised: 04/22/2016] [Accepted: 04/23/2016] [Indexed: 12/25/2022]
Abstract
The common apolipoprotein E alleles (ε4, ε3, and ε2) are important genetic risk factors for late-onset Alzheimer's disease, with the ε4 allele increasing risk and reducing the age of onset and the ε2 allele decreasing risk and markedly delaying the age of onset. Preclinical and clinical studies have shown that apolipoprotein E (APOE) genotype also predicts the timing and amount of brain amyloid-β (Aβ) peptide deposition and amyloid burden (ε4 >ε3 >ε2). Using several administration protocols, we now report that direct intracerebral adeno-associated virus (AAV)-mediated delivery of APOE2 markedly reduces brain soluble (including oligomeric) and insoluble Aβ levels as well as amyloid burden in 2 mouse models of brain amyloidosis whose pathology is dependent on either the expression of murine Apoe or more importantly on human APOE4. The efficacy of APOE2 to reduce brain Aβ burden in either model, however, was highly dependent on brain APOE2 levels and the amount of pre-existing Aβ and amyloid deposition. We further demonstrate that a widespread reduction of brain Aβ burden can be achieved through a single injection of vector via intrathalamic delivery of AAV expressing APOE2 gene. Our results demonstrate that AAV gene delivery of APOE2 using an AAV vector rescues the detrimental effects of APOE4 on brain amyloid pathology and may represent a viable therapeutic approach for treating or preventing Alzheimer's disease especially if sufficient brain APOE2 levels can be achieved early in the course of the disease.
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Affiliation(s)
- Lingzhi Zhao
- Appel Alzheimer's Disease Research Institute, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College of Cornell University, New York, NY, USA.
| | - Andrew J Gottesdiener
- Appel Alzheimer's Disease Research Institute, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College of Cornell University, New York, NY, USA
| | - Mayur Parmar
- Appel Alzheimer's Disease Research Institute, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College of Cornell University, New York, NY, USA
| | - Mingjie Li
- Department of Neurology, Hope Center Viral Vector Core, Washington University, St. Louis, MO, USA
| | - Stephen M Kaminsky
- Department of Genetic Medicine, Weill Cornell Medical College of Cornell University, New York, NY, USA
| | - Maria J Chiuchiolo
- Department of Genetic Medicine, Weill Cornell Medical College of Cornell University, New York, NY, USA
| | - Dolan Sondhi
- Department of Genetic Medicine, Weill Cornell Medical College of Cornell University, New York, NY, USA
| | - Patrick M Sullivan
- Department of Medicine, Duke University Medical Center, Durham Veterans Health Administration Medical Center's Geriatric Research, Education and Clinical Center, Durham, NC, USA
| | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University in St. Louis, St. Louis, MO, USA
| | - Ronald G Crystal
- Department of Genetic Medicine, Weill Cornell Medical College of Cornell University, New York, NY, USA
| | - Steven M Paul
- Appel Alzheimer's Disease Research Institute, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College of Cornell University, New York, NY, USA.
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172
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Mondal T, Wang H, DeKoster GT, Baban B, Gross ML, Frieden C. ApoE: In Vitro Studies of a Small Molecule Effector. Biochemistry 2016; 55:2613-21. [PMID: 27065061 DOI: 10.1021/acs.biochem.6b00324] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Apolipoprotein E4 (apoE4), one of three isoforms of apoE, is the major risk factor for developing late onset Alzheimer's disease. The only differences among these isoforms (apoE2, apoE3, and apoE4) are single amino acid changes. Yet these proteins are functionally very different. One approach to ameliorating the effect of apoE4 with respect to Alzheimer's disease would be to find small molecular weight compounds that affect the behavior of apoE4. Few studies of this approach have been carried out in part because there was no complete structure of any full-length apoE isoform until 2011. Here, we focus on one small molecular weight compound, EZ-482, and explore the effects of its binding to apoE. Using hydrogen-deuterium exchange, we determined that EZ-482 binds to the C-terminal domains of both apoE3 and apoE4. The binding to apoE4, however, is accompanied by a unique N-terminal allosteric effect. Using fluorescence methods, we determined an apparent dissociation constant of approximately 8 μM. Although EZ-482 binds to the C-terminal domain, it blocks heparin binding to the N-terminal domain. The residues of apoE that bind heparin are the same as those involved in apoE binding to LDL and LRP-1 receptors. The methods and the data presented here may serve as a template for future studies using small molecular weight compounds to modulate the behavior of apoE.
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Affiliation(s)
- Tridib Mondal
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine , 660 S. Euclid Avenue, St. Louis, Missouri 63110, United States
| | - Hanliu Wang
- Department of Chemistry, Washington University , One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Gregory T DeKoster
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine , 660 S. Euclid Avenue, St. Louis, Missouri 63110, United States
| | - Berevan Baban
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine , 660 S. Euclid Avenue, St. Louis, Missouri 63110, United States
| | - Michael L Gross
- Department of Chemistry, Washington University , One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Carl Frieden
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine , 660 S. Euclid Avenue, St. Louis, Missouri 63110, United States
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Apolipoprotein E levels and apolipoprotein E genotypes in incident cardiovascular disease risk in subjects of the Prevention of Renal and Vascular End-stage disease study. J Clin Lipidol 2016; 10:842-850. [PMID: 27578115 DOI: 10.1016/j.jacl.2016.03.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 03/05/2016] [Indexed: 11/21/2022]
Abstract
BACKGROUND Apolipoprotein E (apoE) is a component of all major lipoprotein classes with multiple functions including clearance of circulating triglyceride-rich lipoprotein particles and hepatic production of triglyceride-rich lipoprotein, thus affording several avenues for apoE involvement in atherosclerosis development. ApoE has 3 isoforms (E2, E3, and E4) based on a common genetic polymorphism. Numerous studies have been performed assessing cardiovascular disease (CVD) risk relative to the 6 resulting genotypes; however, surprisingly, few studies have been performed assessing risk attributable to apoE plasma levels either alone or in addition also taking into account apoE genotypes. OBJECTIVE To examine the role of apoE levels together with apoE genotypes on incident CVD risk in a large population-based cohort and also to afford preliminary characterization of atherogenic apoE-containing lipoprotein particles. METHODS Cox multivariable proportional hazards modeling was performed on a cohort of the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study as a function of apoE levels and apoE genotypes adjusted for age, gender, and past history of CVD. Further modeling was performed with single addition of clinical and biomarker parameters to elucidate the nature of apoE-associated risk. RESULTS High apoE levels were demonstrated to be associated with CVD risk (hazard ratio per apoE standard deviation, 1.20; 95% confidence interval, 1.11-1.31; P < .0001) both overall and within the high-frequency apoE genotype groups (ε2ε3, ε3ε3, and ε3ε4). Only on addition of apoB-containing lipoprotein parameters to models, did apoE levels lose association with risk. CONCLUSIONS ApoE levels positively associate with incident CVD risk with apoE-associated risk likely residing in apoB-containing lipoproteins.
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174
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Ruiz M, Arias I, Rolón G, Hernández E, Garavito P, Silvera-Redondo C. APOE gene polymorphism analysis in Barranquilla, Colombia. BIOMEDICA : REVISTA DEL INSTITUTO NACIONAL DE SALUD 2016; 36:52-58. [PMID: 27622438 DOI: 10.7705/biomedica.v36i1.2612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Indexed: 06/06/2023]
Abstract
INTRODUCTION The genetic variability present in the APOE gene polymorphism is considered an important factor associated with predisposition to diseases affecting lipid metabolism, as well as heart diseases and Alzheimer's disease, among others. Understanding it as a risk factor in different populations and ethnic groups is a useful tool. OBJECTIVE To analyze the APOE gene polymorphism and determine allelic and genotypic frequencies of a representative sample of population from Barranquilla, Colombia. MATERIALS AND METHODS We performed a descriptive and comparative study. The sample size was 227 unrelated individuals from Barranquilla, Colombia. RESULTS The most frequent allele was the ε3, with 85%, followed by the ε4 allele (13%) and ε2 (1.8%). The genotypes found were: ε3/ε3: 71.8%, ε3/ε4: 24.2%, ε2/ε3: 2.2%, ε2/ε4: 1.3% and ε4/ε4: 0.4%. The ε2/ε2 genotype was not found in this study. The sample exhibited the Hardy-Weinberg equilibrium. CONCLUSION The frequency of the ε3 allele and the ε3/ε3 genotype was similar to that reported in the literature in countries like Brazil, Mexico, Colombia, and in some Colombian Amerindian ethnic groups. The ε2/ε2 genotype was absent. This result is consistent with those found in other population groups worldwide. The frequency of the ε4 allele and the genotypes associated in this population could be related to the presence of diseases such as hypercholesterolemia, myocardial infarction and Alzheimer.
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Affiliation(s)
- Martha Ruiz
- Grupo de Investigación en Genética y Medicina Molecular, Departamento de Medicina, Universidad del Norte, Barranquilla, Colombia.
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Shao Y, Yamamoto M, Figeys D, Ning Z, Chan HM. Proteome profiling reveals regional protein alteration in cerebrum of common marmoset (Callithrix jacchus) exposed to methylmercury. Toxicology 2016; 347-349:29-39. [DOI: 10.1016/j.tox.2016.03.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 02/28/2016] [Accepted: 03/03/2016] [Indexed: 10/22/2022]
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176
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Wintjens R, Bozon D, Belabbas K, MBou F, Girardet JP, Tounian P, Jolly M, Boccara F, Cohen A, Karsenty A, Dubern B, Carel JC, Azar-Kolakez A, Feillet F, Labarthe F, Gorsky AMC, Horovitz A, Tamarindi C, Kieffer P, Lienhardt A, Lascols O, Di Filippo M, Dufernez F. Global molecular analysis and APOE mutations in a cohort of autosomal dominant hypercholesterolemia patients in France. J Lipid Res 2016; 57:482-91. [PMID: 26802169 DOI: 10.1194/jlr.p055699] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Indexed: 11/20/2022] Open
Abstract
Autosomal dominant hypercholesterolemia (ADH) is a human disorder characterized phenotypically by isolated high-cholesterol levels. Mutations in the low density lipoprotein receptor (LDLR), APOB, and proprotein convertase subtilisin/kexin type 9 (PCSK9) genes are well known to be associated with the disease. To characterize the genetic background associated with ADH in France, the three ADH-associated genes were sequenced in a cohort of 120 children and 109 adult patients. Fifty-one percent of the cohort had a possible deleterious variant in LDLR, 3.1% in APOB, and 1.7% in PCSK9. We identified 18 new variants in LDLR and 2 in PCSK9. Three LDLR variants, including two newly identified, were studied by minigene reporter assay confirming the predicted effects on splicing. Additionally, as recently an in-frame deletion in the APOE gene was found to be linked to ADH, the sequencing of this latter gene was performed in patients without a deleterious variant in the three former genes. An APOE variant was identified in three patients with isolated severe hypercholesterolemia giving a frequency of 1.3% in the cohort. Therefore, even though LDLR mutations are the major cause of ADH with a large mutation spectrum, APOE variants were found to be significantly associated with the disease. Furthermore, using structural analysis and modeling, the identified APOE sequence changes were predicted to impact protein function.
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Affiliation(s)
- René Wintjens
- Faculty of Pharmacy (CP206/04), Université Libre de Bruxelles, B-1050 Brussels, Belgium
| | | | - Khaldia Belabbas
- Laboratoire Commun de Biologie et Génétiques Moléculaires (LCBGM), AP-HP (Assistance Publique-Hopitaux de Paris), Hôpital Saint-Antoine, F-75012, Paris, France
| | - Félicien MBou
- Service d'Endocrinologie, CHU du Lamentin, F-97232 Le Lamentin, Martinique, France
| | - Jean-Philippe Girardet
- Service de Gastroentérologie et Nutrition Pédiatrique, AP-HP, Hôpital Trousseau, F-75012, Paris, France
| | - Patrick Tounian
- Service de Gastroentérologie et Nutrition Pédiatrique, AP-HP, Hôpital Trousseau, F-75012, Paris, France
| | - Mathilde Jolly
- Service d'Endocrinologie, Diabétologie et Nutrition, CH Angers, F-49933, Angers, France
| | - Franck Boccara
- Service d'Endocrinologie, Diabétologie et Nutrition, CH Angers, F-49933, Angers, France
| | - Ariel Cohen
- Service d'Endocrinologie, Diabétologie et Nutrition, CH Angers, F-49933, Angers, France
| | - Alexandra Karsenty
- Service de Gastroentérologie et Nutrition Pédiatrique, AP-HP, Hôpital Trousseau, F-75012, Paris, France
| | - Béatrice Dubern
- Service de Gastroentérologie et Nutrition Pédiatrique, AP-HP, Hôpital Trousseau, F-75012, Paris, France
| | - Jean-Claude Carel
- Université Paris Diderot, Sorbonne Paris Cité, F-75019, Paris, France Service d'Endocrinologie Diabétologie Pédiatrique et Centre de Référence des Maladies Endocriniennes Rares de la Croissance, AP-HP, Hôpital Robert Debré, F-75019, Paris, France
| | - Ahlam Azar-Kolakez
- Université Paris Diderot, Sorbonne Paris Cité, F-75019, Paris, France Service d'Endocrinologie Diabétologie Pédiatrique et Centre de Référence des Maladies Endocriniennes Rares de la Croissance, AP-HP, Hôpital Robert Debré, F-75019, Paris, France
| | - François Feillet
- Service de Médecine Infantile et de génétique clinique, CHU Nancy-Brabois, F-54511 Vandoeuvre les Nancy, France INSERM NGERE UMR 954, F-54500, Vandoeuvre les Nancy, France
| | - François Labarthe
- Service de médecine pédiatrique, Hopital Clocheville, CHU Tours, F-37044, Tours, France
| | | | - Alice Horovitz
- Service de Cardiologie, CHU Bordeaux-Haut Lévêque, F-33604, Pessac, France
| | | | - Pierre Kieffer
- Service de Médecine Interne, CH Mulhouse, Hôpital E. Muller, F-68070 Mulhouse, France
| | - Anne Lienhardt
- Service de Pédiatrie Médicale, CH Limoges, Hôpital mère/enfants, F-87042 Limoges, France
| | - Olivier Lascols
- Laboratoire Commun de Biologie et Génétiques Moléculaires (LCBGM), AP-HP (Assistance Publique-Hopitaux de Paris), Hôpital Saint-Antoine, F-75012, Paris, France
| | - Mathilde Di Filippo
- Centre de Biologie et de Pathologie Est, CHU Lyon, France Service de Pédiatrie Médicale, CH Limoges, Hôpital mère/enfants, F-87042 Limoges, France
| | - Fabienne Dufernez
- Laboratoire Commun de Biologie et Génétiques Moléculaires (LCBGM), AP-HP (Assistance Publique-Hopitaux de Paris), Hôpital Saint-Antoine, F-75012, Paris, France
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Zhong L, Xie YZ, Cao TT, Wang Z, Wang T, Li X, Shen RC, Xu H, Bu G, Chen XF. A rapid and cost-effective method for genotyping apolipoprotein E gene polymorphism. Mol Neurodegener 2016; 11:2. [PMID: 26754117 PMCID: PMC4710020 DOI: 10.1186/s13024-016-0069-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/04/2016] [Indexed: 11/10/2022] Open
Abstract
Background Apolipoprotein E (ApoE) is a major cholesterol carrier and plays an important role in maintaining lipid homeostasis both in the periphery and brain. Human APOE gene is polymorphic at two single nucleotides (rs429358 and rs7412) resulting in three different alleles (ε2, ε3 and ε4). ApoE isoforms modulate the risk for a variety of vascular and neurodegenerative diseases; thus, APOE genotyping is crucial for predicting disease risk and designing individualized therapy based on APOE genotype. Results We have developed an APOE genotyping method that is based on allele-specific PCR methodology adapted to Real Time PCR monitored by TaqMan probe. Rather than using TaqMan probes specific for the two polymorphic sites, only one TaqMan probe is used as the polymorphic alleles are recognized by site-specific PCR primers. Each genotyping assay can be completed within 90 minutes and is applicable to high-throughput analysis. Using this protocol, we genotyped a total of 1158 human DNA samples and obtained a 100 % concordance with the APOE genotype determined by sequencing analysis. Conclusion The APOE genotyping assay we have developed is accurate and cost-effective. In addition, our assay can readily be applied to genotyping large sample numbers. Therefore, our APOE genotyping method can be used for assessing the risk for a variety of vascular and neurodegenerative diseases that have been reported to be associated with APOE polymorphism.
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Affiliation(s)
- Li Zhong
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China.
| | - Yong-Zhuang Xie
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China.
| | - Tian-Tian Cao
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China.
| | - Zongqi Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China.
| | - Tingting Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China.
| | - Xinxiu Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China.
| | - Rui-Chi Shen
- Fujian Institute of Subtropical Botany, Xiamen, 361006, China.
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China.
| | - Guojun Bu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China. .,Department of Neuroscience, Mayo Clinic, Jacksonville, FL, 32224, USA.
| | - Xiao-Fen Chen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen, 361102, China.
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178
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Li XB, Wang J, Xu AD, Huang JM, Meng LQ, Huang RY, Wang JL. Apolipoprotein E polymorphisms increase the risk of post-stroke depression. Neural Regen Res 2016; 11:1790-1796. [PMID: 28123423 PMCID: PMC5204235 DOI: 10.4103/1673-5374.194748] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Recent reports have shown that apolipoprotein E (APOE) polymorphisms are involved in neurodegenerative disease. However, it is unclear whether APOE affects post-stroke depression. Accordingly, we hypothesized that APOE polymorphisms modify the risk of post-stroke depression. Here, we performed a hospital-based case-control study (including 76 cerebral infarction cases with post-stroke depression, 88 cerebral infarction cases without post-stroke depression, and 109 controls without any evidence of post-stroke depression or cerebral infarction) to determine possible association between APOE rs429358 and rs7412 polymorphisms and risk of post-stroke depression. Our findings show no difference among the groups with regards genotype distribution of the rs7412 polymorphism. In contrast, APOE genotypes with rs429358-C alleles increased the risk of post-stroke depression. Further, the rs429358 polymorphism was associated with significantly decreased regional cerebral blood flow values in the left temporal lobe of post-stroke depression cases. Additionally, the rs429358 polymorphism was not only associated with depression severity, but with increasing serum levels of total cholesterol. These results suggest that the APOE rs429358 polymorphism is associated with increased risk of developing post-stroke depression, and that APOE rs429358-C allele genotypes may be detrimental to recovery of nerve function after stoke. Indeed, these findings provide clinical data for future post-stroke depression gene interventions.
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Affiliation(s)
- Xue-Bin Li
- Stroke Center & Neurology Division, the First Affiliated Hospital of Jinan University, Guangzhou, Guangdong Province, China; Department of Neurology, the Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Zhuang Autonomous Region, China
| | - Jie Wang
- Department of Nephrology, the Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Zhuang Autonomous Region, China
| | - An-Ding Xu
- Stroke Center & Neurology Division, the First Affiliated Hospital of Jinan University, Guangzhou, Guangdong Province, China
| | - Jian-Min Huang
- Department of Neurology, the Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Zhuang Autonomous Region, China
| | - Lan-Qing Meng
- Department of Neurology, the Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Zhuang Autonomous Region, China
| | - Rui-Ya Huang
- Department of Neurology, the Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Zhuang Autonomous Region, China
| | - Jun-Li Wang
- Department of Laboratory Medicines, the Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, Guangxi Zhuang Autonomous Region, China
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179
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Montoliu-Gaya L, Villegas S. Protein structures in Alzheimer's disease: The basis for rationale therapeutic design. Arch Biochem Biophys 2015; 588:1-14. [DOI: 10.1016/j.abb.2015.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/24/2015] [Accepted: 10/09/2015] [Indexed: 01/06/2023]
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180
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Rezazadeh M, Khorrami A, Yeghaneh T, Talebi M, Kiani SJ, Heshmati Y, Gharesouran J. Genetic Factors Affecting Late-Onset Alzheimer's Disease Susceptibility. Neuromolecular Med 2015; 18:37-49. [PMID: 26553058 DOI: 10.1007/s12017-015-8376-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 10/19/2015] [Indexed: 11/29/2022]
Abstract
Alzheimer's disease is considered a progressive brain disease in the older population. Late-onset Alzheimer's disease (LOAD) as a multifactorial dementia has a polygenic inheritance. Age, environment, and lifestyle along with a growing number of genetic factors have been reported as risk factors for LOAD. Our aim was to present results of LOAD association studies that have been done in northwestern Iran, and we also explored possible interactions with apolipoprotein E (APOE) status. We re-evaluated the association of these markers in dominant, recessive, and additive models. In all, 160 LOAD and 163 healthy control subjects of Azeri Turkish ethnicity were studied. The Chi-square test with Yates' correction and Fisher's exact test were used for statistical analysis. A Bonferroni-corrected p value, based on the number of statistical tests, was considered significant. Our results confirmed that chemokine receptor type 2 (CCR2), estrogen receptor 1 (ESR1), toll-like receptor 2 (TLR2), tumor necrosis factor alpha (TNF α), APOE, bridging integrator 1 (BIN1), and phosphatidylinositol-binding clathrin assembly protein (PICALM) are LOAD susceptibility loci in Azeri Turk ancestry populations. Among them, variants of CCR2, ESR1, TNF α, and APOE revealed associations in three different genetic models. After adjusting for APOE, the association (both allelic and genotypic) with CCR2, BIN1, and ESRα (PvuII) was evident only among subjects without the APOE ε4, whereas the association with CCR5, without Bonferroni correction, was significant only among subjects carrying the APOE ε4 allele. This result is an evidence of a synergistic and antagonistic effect of APOE on variant associations with LOAD.
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Affiliation(s)
- Maryam Rezazadeh
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Aziz Khorrami
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Tarlan Yeghaneh
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mahnaz Talebi
- Neuroscience Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Seyed Jalal Kiani
- Virology Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Yaser Heshmati
- Department of Medicine, Huddinge, H7, Karolinska Institutet, Stockholm, Sweden
| | - Jalal Gharesouran
- Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
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181
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Amemori T, Jendelova P, Ruzicka J, Urdzikova LM, Sykova E. Alzheimer's Disease: Mechanism and Approach to Cell Therapy. Int J Mol Sci 2015; 16:26417-51. [PMID: 26556341 PMCID: PMC4661820 DOI: 10.3390/ijms161125961] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/26/2015] [Accepted: 10/26/2015] [Indexed: 12/19/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia. The risk of AD increases with age. Although two of the main pathological features of AD, amyloid plaques and neurofibrillary tangles, were already recognized by Alois Alzheimer at the beginning of the 20th century, the pathogenesis of the disease remains unsettled. Therapeutic approaches targeting plaques or tangles have not yet resulted in satisfactory improvements in AD treatment. This may, in part, be due to early-onset and late-onset AD pathogenesis being underpinned by different mechanisms. Most animal models of AD are generated from gene mutations involved in early onset familial AD, accounting for only 1% of all cases, which may consequently complicate our understanding of AD mechanisms. In this article, the authors discuss the pathogenesis of AD according to the two main neuropathologies, including senescence-related mechanisms and possible treatments using stem cells, namely mesenchymal and neural stem cells.
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Affiliation(s)
- Takashi Amemori
- Department of Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
| | - Pavla Jendelova
- Department of Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
- Department of Neuroscience, 2nd Faculty of Medicine, Charles University, V Uvalu 84, 150 06 Prague 5, Czech Republic.
| | - Jiri Ruzicka
- Department of Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
| | - Lucia Machova Urdzikova
- Department of Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
| | - Eva Sykova
- Department of Neuroscience, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
- Department of Neuroscience, 2nd Faculty of Medicine, Charles University, V Uvalu 84, 150 06 Prague 5, Czech Republic.
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182
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Influence of Abdominal Obesity on the Lipid-Lipoprotein Profile in Apoprotein E2/4 Carriers: The Effect of an Apparent Duality. J Lipids 2015; 2015:742408. [PMID: 26605088 PMCID: PMC4641183 DOI: 10.1155/2015/742408] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/07/2015] [Indexed: 11/20/2022] Open
Abstract
Background. Apolipoprotein (Apo) E plays a key role in the handling of lipoprotein particles with ApoE2 and ApoE4 frequently having opposite effects compared to ApoE3. Some individuals simultaneously carry both E2 and E4 alleles. The impact of the ApoE2/4 genotype on lipid concentrations and its consequences on health remain poorly documented. Objective. This study compared the lipid profile between ApoE2/4 carriers and other ApoE genotypes in relation to the waist circumference. Methods. Cholesterol, triglyceride (TG), and ApoB concentrations were measured among 2,680 Caucasians. Multivariate logistic regression models were used to estimate the contribution of ApoE2/4 to various dyslipidemic profiles associated with abdominal obesity. Results. In presence of abdominal obesity, the lipid profile was as deteriorated in ApoE2/4 carriers as in carriers of other ApoE genotypes. There was a more pronounced effect on TG-rich lipoproteins, particularly in ApoE2/2 (a feature of type III dysbetalipoproteinemia), and non-high-density lipoprotein (HDL) cholesterol in ApoE4/4. Compared to ApoE2/2, ApoE2/4 carriers presented lower very-low-density lipoprotein (VLDL) cholesterol concentrations and VLDL-cholesterol/TG ratios, with or without obesity, and higher low-density lipoprotein (LDL) cholesterol concentrations. Conclusion. In presence of abdominal obesity, the influence of the ApoE2 allele could be less pronounced than that of ApoE4 among ApoE2/4 individuals.
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183
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ApoE4-specific Misfolded Intermediate Identified by Molecular Dynamics Simulations. PLoS Comput Biol 2015; 11:e1004359. [PMID: 26506597 PMCID: PMC4623519 DOI: 10.1371/journal.pcbi.1004359] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 05/28/2015] [Indexed: 11/19/2022] Open
Abstract
The increased risk of developing Alzheimer's disease (AD) is associated with the APOE gene, which encodes for three variants of Apolipoprotein E, namely E2, E3, E4, differing only by two amino acids at positions 112 and 158. ApoE4 is known to be the strongest risk factor for AD onset, while ApoE3 and ApoE2 are considered to be the AD-neutral and AD-protective isoforms, respectively. It has been hypothesized that the ApoE isoforms may contribute to the development of AD by modifying the homeostasis of ApoE physiological partners and AD-related proteins in an isoform-specific fashion. Here we find that, despite the high sequence similarity among the three ApoE variants, only ApoE4 exhibits a misfolded intermediate state characterized by isoform-specific domain-domain interactions in molecular dynamics simulations. The existence of an ApoE4-specific intermediate state can contribute to the onset of AD by altering multiple cellular pathways involved in ApoE-dependent lipid transport efficiency or in AD-related protein aggregation and clearance. We present what we believe to be the first structural model of an ApoE4 misfolded intermediate state, which may serve to elucidate the molecular mechanism underlying the role of ApoE4 in AD pathogenesis. The knowledge of the structure for the ApoE4 folding intermediate provides a new platform for the rational design of alternative therapeutic strategies to fight AD.
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184
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Haapasalo K, van Kessel K, Nissilä E, Metso J, Johansson T, Miettinen S, Varjosalo M, Kirveskari J, Kuusela P, Chroni A, Jauhiainen M, van Strijp J, Jokiranta TS. Complement Factor H Binds to Human Serum Apolipoprotein E and Mediates Complement Regulation on High Density Lipoprotein Particles. J Biol Chem 2015; 290:28977-87. [PMID: 26468283 DOI: 10.1074/jbc.m115.669226] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Indexed: 11/06/2022] Open
Abstract
The alternative pathway of complement is an important part of the innate immunity response against foreign particles invading the human body. To avoid damage to host cells, it needs to be efficiently down-regulated by plasma factor H (FH) as exemplified by various diseases caused by mutations in its domains 19-20 (FH19-20) and 5-7 (FH5-7). These regions are also the main interaction sites for microbial pathogens that bind host FH to evade complement attack. We previously showed that inhibition of FH binding by a recombinant FH5-7 construct impairs survival of FH binding pathogens in human blood. In this study we found that upon exposure to full blood, the addition of FH5-7 reduces survival of, surprisingly, also those microbes that are not able to bind FH. This effect was mediated by inhibition of complement regulation and subsequently enhanced neutrophil phagocytosis by FH5-7. We found that although FH5-7 does not reduce complement regulation in the actual fluid phase of plasma, it reduces regulation on HDL particles in plasma. Using affinity chromatography and mass spectrometry we revealed that FH interacts with serum apolipoprotein E (apoE) via FH5-7 domains. Furthermore, binding of FH5-7 to HDL was dependent on the concentration of apoE on the HDL particles. These findings explain why the addition of FH5-7 to plasma leads to excessive complement activation and phagocytosis of microbes in full anticoagulated blood. In conclusion, our data show how FH interacts with apoE molecules via domains 5-7 and regulates alternative pathway activation on plasma HDL particles.
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Affiliation(s)
- Karita Haapasalo
- From the Department of Bacteriology and Immunology, Haartman Institute, and Research Programs Unit, Immunobiology, University of Helsinki, FIN-00014 Helsinki, Finland, Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands,
| | - Kok van Kessel
- Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Eija Nissilä
- From the Department of Bacteriology and Immunology, Haartman Institute, and Research Programs Unit, Immunobiology, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Jari Metso
- Department of Molecular Medicine, National Institute for Health and Welfare, Biomedicum, FI-00290 Helsinki, Finland
| | - Tiira Johansson
- From the Department of Bacteriology and Immunology, Haartman Institute, and Research Programs Unit, Immunobiology, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Sini Miettinen
- University of Helsinki, Institute of Biotechnology, 00014 Helsinki, Finland
| | - Markku Varjosalo
- University of Helsinki, Institute of Biotechnology, 00014 Helsinki, Finland
| | - Juha Kirveskari
- HUSLAB, Helsinki University Central Hospital Laboratory, 00290 Helsinki, Finland, and
| | - Pentti Kuusela
- HUSLAB, Helsinki University Central Hospital Laboratory, 00290 Helsinki, Finland, and
| | - Angelika Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos," 15310 Athens, Greece
| | - Matti Jauhiainen
- Department of Molecular Medicine, National Institute for Health and Welfare, Biomedicum, FI-00290 Helsinki, Finland
| | - Jos van Strijp
- Medical Microbiology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - T Sakari Jokiranta
- From the Department of Bacteriology and Immunology, Haartman Institute, and Research Programs Unit, Immunobiology, University of Helsinki, FIN-00014 Helsinki, Finland
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185
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MacKay DS, Eck PK, Gebauer SK, Baer DJ, Jones PJ. CYP7A1-rs3808607 and APOE isoform associate with LDL cholesterol lowering after plant sterol consumption in a randomized clinical trial. Am J Clin Nutr 2015; 102:951-7. [PMID: 26333513 DOI: 10.3945/ajcn.115.109231] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 07/31/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The benefits of plant sterols (PSs) for cholesterol lowering are hampered by large heterogeneity across individuals, potentially because of genetic polymorphisms. OBJECTIVE We investigated the impact of candidate genetic variations on cholesterol response to PSs in a trial that recruited individuals with high or low endogenous cholesterol synthesis, estimated by lathosterol to cholesterol (L:C) ratio. DESIGN Mildly hypercholesterolemic adults preselected as possessing either high endogenous cholesterol synthesis (n = 24; mean ± SEM: L:C ratio = 2.03 ± 0.39 μmol/mmol) or low endogenous cholesterol synthesis (n = 39; mean ± SEM: L:C ratio = 0.99 ± 0.28 μmol/mmol) consumed 2 g PS/d or a placebo for 28 d by using a dual-center, single-blind, randomized crossover design. Cholesterol synthesis and change in cholesterol absorption were measured with stable isotopic tracers. Candidate single-nucleotide polymorphisms and apolipoprotein E (APOE) isoform were assessed by TaqMan genotyping assay. RESULTS The cholesterol fractional synthesis rate was higher (P < 0.001) in participants with high endogenous cholesterol synthesis (mean ± SEM: placebo: 9.16% ± 0.47%; PSs: 9.74% ± 0.47%) than in participants with low endogenous cholesterol synthesis (mean ± SEM placebo: 5.72% ± 0.43%; PS: 7.10% ± 0.43%). Low-density lipoprotein (LDL) cholesterol lowering in response to PSs was associated with individuals' genotypes. Cholesterol 7 alpha-hydroxylase (CYP7A1-rs3808607) T/T homozygotes showed no LDL cholesterol lowering (mean ± SEM: -0.05 ± 0.07 mmol/L, P = 0.9999, n = 20), whereas the presence of the G-allele associated with LDL cholesterol response in a dose-dependent fashion (mean ± SEM G/T: -0.22 ± 0.06 mmol/L, P = 0.0006, n = 35; G/G: -0.46 ± 0.12 mmol/L, P = 0.0009, n = 8). Similarly, APOE ɛ3 carriers (mean ± SEM: -0.13 ± 0.05 mmol/L, P = 0.0370, n = 40) responded less than APOE ɛ4 carriers (mean ± SEM: -0.31 ± 0.07 mmol/L, P < 0.0001, n = 23). Moreover, genoset CYP7A1-rs3808607 T/T/APOE ɛ3 was associated with nonresponsiveness (mean ± SEM: +0.09 ± 0.08 mmol/L, P = 0.9999, n = 14). rs5882 in cholesteryl ester transfer protein (CETP) and rs4148217 in ATP-binding cassette subfamily G member 8 (ABCG8) did not associate with LDL cholesterol lowering. Cholesterol absorption decreased as a result of PS consumption, but this decrease was not related to circulating LDL cholesterol concentrations, cholesterol synthesis phenotype, or genotypes. CONCLUSION CYP7A1-rs3808607 and APOE isoform are associated with the extent of reduction in circulating LDL cholesterol in response to PS consumption and could serve as potential predictive genetic markers to identify individuals who would derive maximum LDL cholesterol lowering with PS consumption. The trial was registered at clinicaltrials.gov as NCT01131832.
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Affiliation(s)
- Dylan S MacKay
- Richardson Centre for Functional Foods and Nutraceuticals, Department of Human Nutritional Sciences
| | | | - Sarah K Gebauer
- USDA, Agricultural Research Service, Beltsville Human Nutrition Research Center, Beltsville, MD, and
| | - David J Baer
- USDA, Agricultural Research Service, Beltsville Human Nutrition Research Center, Beltsville, MD, and
| | - Peter Jh Jones
- Richardson Centre for Functional Foods and Nutraceuticals, Department of Human Nutritional Sciences, Department of Food Science, University of Manitoba, Winnipeg, Canada
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186
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Neuronal Regulation of Neuroprotective Microglial Apolipoprotein E Secretion in Rat In Vitro Models of Brain Pathophysiology. J Neuropathol Exp Neurol 2015; 74:818-34. [PMID: 26185969 DOI: 10.1097/nen.0000000000000222] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
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.
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187
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Al-Asmary SM, Kadasah S, Arfin M, Tariq M, Al-Asmari A. Apolipoprotein E polymorphism is associated with susceptibility to schizophrenia among Saudis. Arch Med Sci 2015; 11:869-76. [PMID: 26322100 PMCID: PMC4548040 DOI: 10.5114/aoms.2015.53308] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 07/12/2013] [Accepted: 09/10/2013] [Indexed: 01/12/2023] Open
Abstract
INTRODUCTION Apolipoprotein E (APOE) genotypes influence the phenotype of several neurodegenerative disorders including Alzheimer's and Parkinson disease and may affect schizophrenia pathogenesis. This study was undertaken to determine the association between APOE gene polymorphisms and schizophrenia in the Saudi population. MATERIAL AND METHODS APOE allele and genotype frequencies were studied in 380 Saudi subjects including schizophrenia patients and matched controls using polymerase chain reaction (PCR) and reverse-hybridization techniques. RESULTS The frequencies of the APOE allele ε2 and genotypes ε2/ε3 and ε2/ε4 were significantly higher in the schizophrenia patients as compared to controls, suggesting that the ε2 allele and its heterozygous genotypes may increase the susceptibility to schizophrenia. In contrast, the frequencies of the ε3 allele and ε3/ε3 genotype were lower in patients as compared to controls, suggesting a protective effect of APOE ε3 for schizophrenia. This study indicated that APOE ε4 was differentially associated with schizophrenia depending on the symptoms as the frequency of the ε4 allele was significantly higher in schizophrenia patients with positive symptoms. By contrast, no significant association between APOE ε4 and schizophrenia patients with negative symptoms was observed. Genotypes ε2/ε2 and ε4/ε4 were absent in patients and controls. Moreover, the age of onset was significantly lower in patients with the APOE ε2/ε3 genotype. There was no significant difference in the frequencies of APOE alleles and genotypes between male and female schizophrenia patients. CONCLUSIONS The results of this study clearly show that APOE alleles and genotypes are associated with risk of developing schizophrenia and early age of onset in Saudis.
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Affiliation(s)
| | - Saeed Kadasah
- Department of Psychiatry, Riyadh Military Hospital, Riyadh, Saudi Arabia
| | - Misbahul Arfin
- Research Center, Riyadh Military Hospital, Riyadh, Saudi Arabia
| | - Mohammad Tariq
- Research Center, Riyadh Military Hospital, Riyadh, Saudi Arabia
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188
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Kim SH, Adhikari BB, Cruz S, Schramm MP, Vinson JA, Narayanaswami V. Targeted intracellular delivery of resveratrol to glioblastoma cells using apolipoprotein E-containing reconstituted HDL as a nanovehicle. PLoS One 2015; 10:e0135130. [PMID: 26258481 PMCID: PMC4530947 DOI: 10.1371/journal.pone.0135130] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 07/18/2015] [Indexed: 11/23/2022] Open
Abstract
The objective of this study is to transport and deliver resveratrol to intracellular sites using apolipoprotein E3 (apoE3). Reconstituted high-density lipoprotein (rHDL) bearing resveratrol (rHDL/res) was prepared using phospholipids and the low-density lipoprotein receptor (LDLr)-binding domain of apoE3. Biophysical characterization revealed that resveratrol was partitioned into the phospholipid bilayer of discoidal rHDL/res particles (~19 nm diameter). Co-immunoprecipitation studies indicated that the LDLr-binding ability of apoE3 was retained. Cellular uptake of resveratrol to intracellular sites was evaluated in glioblastoma A-172 cells by direct fluorescence using chemically synthesized NBD-labeled resveratrol (res/NBD) embedded in rHDL/res. Competition and inhibition studies indicate that the uptake is by receptor mediated endocytosis via the LDLr, with co-localization of apoE3 and res/NBD in late endosomes/lysosomes. We propose that rHDL provides an ideal hydrophobic milieu to sequester resveratrol and that rHDL containing apoE3 serves as an effective “nanovehicle” to transport and deliver resveratrol to targeted intracellular sites.
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Affiliation(s)
- Sea H. Kim
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, California, United States of America
| | - Birendra Babu Adhikari
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, California, United States of America
| | - Siobanth Cruz
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, California, United States of America
| | - Michael P. Schramm
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, California, United States of America
| | - Joe A. Vinson
- Chemistry Department, Loyola Science Center, University of Scranton, Scranton, Pennsylvania, United States of America
| | - Vasanthy Narayanaswami
- Department of Chemistry and Biochemistry, California State University Long Beach, Long Beach, California, United States of America
- * E-mail:
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189
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Phillips MC. Apolipoprotein E isoforms and lipoprotein metabolism. IUBMB Life 2015; 66:616-23. [PMID: 25328986 DOI: 10.1002/iub.1314] [Citation(s) in RCA: 199] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 09/09/2014] [Indexed: 11/09/2022]
Abstract
Apolipoprotein (apo) E is a 299-residue protein which functions as a key regulator of plasma lipid levels. Human apoE exists as three common isoforms and the parent form, apoE3, operates optimally in promoting clearance of triglyceride (TG)-rich lipoproteins and is associated with normal plasma lipid levels. This result occurs because apoE3 possesses both the requisite lipid-binding ability and affinity for the low density lipoprotein receptor (LDLR) to mediate appropriate lipolytic processing and endocytosis of TG-rich lipoprotein remnant particles. ApoE2 which differs from apoE3 by the single amino acid substitution Arg158Cys located near the LDLR recognition site exhibits impaired binding to the receptor and an inability to promote clearance of TG-rich lipoprotein remnant particles; this isoform is associated with Type-III hyperlipoproteinemia. ApoE4 which differs from apoE3 by the single amino acid substitution Cys112Arg is also associated with dyslipidemia although binding of this isoform to the LDLR is unaffected. The amino acid substitution affects the organization and stability of both the N-terminal helix bundle domain and separately folded C-terminal domain so that apoE4 has enhanced lipid binding ability. As a consequence, apoE4 binds better than apoE3 to the surface of very low density lipoprotein (VLDL) particles and impairs their lipolytic processing in the circulation so that apoE4 is associated with a more pro-atherogenic lipoprotein-cholesterol distribution (higher VLDL-cholesterol/high density lipoprotein-cholesterol ratio). This review summarizes current understanding of the structural differences between apoE2, apoE3, and apoE4, and the molecular mechanisms responsible for the alterations in lipoprotein metabolism resulting from this polymorphism of apoE. Detailed knowledge of how expression of structurally distinct apoE variants modifies lipoprotein metabolism provides a basis for developing ways to manipulate the functionality of apoE in vivo.
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Affiliation(s)
- Michael C Phillips
- Division of Translational Medicine and Human Genetics, Perelman School of Medicine at the University of Pennsylvania, 11-130 Translational Research Center, Philadelphia, PA, USA
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190
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Klapper Y, Maffre P, Shang L, Ekdahl KN, Nilsson B, Hettler S, Dries M, Gerthsen D, Nienhaus GU. Low affinity binding of plasma proteins to lipid-coated quantum dots as observed by in situ fluorescence correlation spectroscopy. NANOSCALE 2015; 7:9980-9984. [PMID: 25975280 DOI: 10.1039/c5nr01694k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Protein binding to lipid-coated nanoparticles has been pursued quantitatively by using fluorescence correlation spectroscopy. The binding of three important plasma proteins to lipid-enwrapped quantum dots (QDs) shows very low affinity, with an apparent dissociation coefficient in the range of several hundred micromolar. Thus, the tendency to adsorb is orders of magnitude weaker than for QDs coated with dihydrolipoic acid.
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Affiliation(s)
- Yvonne Klapper
- Institute of Applied Physics and Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
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191
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Analysis of differentially expressed novel post-translational modifications of plasma apolipoprotein E in Taiwanese females with breast cancer. J Proteomics 2015; 126:252-62. [PMID: 26079612 DOI: 10.1016/j.jprot.2015.05.038] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Revised: 05/07/2015] [Accepted: 05/24/2015] [Indexed: 12/22/2022]
Abstract
APOE ε2 or ε4 alleles being used as indicators of breast cancer risk are controversial in Taiwanese females. We provide a concept for relative comparisons of post-translational modifications (PTMs) of plasma apolipoprotein E (ApoE) between normal controls and breast cancer patients to investigate the association of ApoE with breast cancer risk. APOE polymorphisms (ApoE isoforms) were not assessed in this study. The relative modification ratio (%) of 15 targeted and 21 modified peptides were evaluated by 1D SDS-PAGE, in-gel digestion, and label-free nano-LC/MS to compare normal controls with breast cancer patients. Plasma levels of the ApoE protein did not significantly differ between normal controls and breast cancer patients. Eleven sites with novel PTMs were identified from 7 pairs of differentially expressed targeted and modified peptides according to the relative modification ratio including methylation at the E3 (↑1.45-fold), E7 (↑1.45-fold), E11 (↑1.19-fold), E77 (↑2.02-fold), E87 (↑2.02-fold), and Q98 (↑1.62-fold) residues; dimethylation at the Q187 (↑1.44-fold) residue; dihydroxylation at the R92 (↑1.25-fold), K95 (↑1.25-fold), and R103 (↑1.25-fold) residues; and glycosylation at the S129 (↑1.14-fold) residue. The clustered methylation and dihydroxylation of plasma ApoE proteins may play a role in breast cancer.
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192
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Van der Horst DJ, Rodenburg KW. Lipoprotein assembly and function in an evolutionary perspective. Biomol Concepts 2015; 1:165-83. [PMID: 25961995 DOI: 10.1515/bmc.2010.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Circulatory fat transport in animals relies on members of the large lipid transfer protein (LLTP) superfamily, including mammalian apolipoprotein B (apoB) and insect apolipophorin II/I (apoLp-II/I). ApoB and apoLp-II/I, constituting the structural (non-exchangeable) basis for the assembly of various lipoproteins, acquire lipids through microsomal triglyceride-transfer protein, another LLTP family member, and bind them by means of amphipathic α-helical and β-sheet structural motifs. Comparative research reveals that LLTPs evolved from the earliest animals and highlights the structural adaptations in these lipid-binding proteins. Thus, in contrast to apoB, apoLp-II/I is cleaved post-translationally by a furin, resulting in the appearance of two non-exchangeable apolipoproteins in the single circulatory lipoprotein in insects, high-density lipophorin (HDLp). The remarkable structural similarities between mammalian and insect lipoproteins notwithstanding important functional differences relate to the mechanism of lipid delivery. Whereas in mammals, partial delipidation of apoB-containing lipoproteins eventually results in endocytic uptake of their remnants, mediated by members of the low-density lipoprotein receptor (LDLR) family, and degradation in lysosomes, insect HDLp functions as a reusable lipid shuttle capable of alternate unloading and reloading of lipid. Also, during muscular efforts (flight activity), an HDLp-based lipoprotein shuttle provides for the transport of lipid for energy generation. Although a lipophorin receptor - a homolog of LDLR - was identified that mediates endocytic uptake of HDLp during specific developmental periods, the endocytosed lipoprotein appears to be recycled in a transferrin-like manner. These data highlight that the functional adaptations in the lipoprotein lipid carriers in mammals and insects also emerge with regard to the functioning of their cognate receptors.
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193
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Inekci D, Jonesco DS, Kennard S, Karsdal MA, Henriksen K. The potential of pathological protein fragmentation in blood-based biomarker development for dementia - with emphasis on Alzheimer's disease. Front Neurol 2015; 6:90. [PMID: 26029153 PMCID: PMC4426721 DOI: 10.3389/fneur.2015.00090] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 04/10/2015] [Indexed: 12/12/2022] Open
Abstract
The diagnosis of dementia is challenging and early stages are rarely detected limiting the possibilities for early intervention. Another challenge is the overlap in the clinical features across the different dementia types leading to difficulties in the differential diagnosis. Identifying biomarkers that can detect the pre-dementia stage and allow differential diagnosis could provide an opportunity for timely and optimal intervention strategies. Also, such biomarkers could help in selection and inclusion of the right patients in clinical trials of both Alzheimer’s disease and other dementia treatment candidates. The cerebrospinal fluid (CSF) has been the most investigated source of biomarkers and several candidate proteins have been identified. However, looking solely at protein levels is too simplistic to provide enough detailed information to differentiate between dementias, as there is a significant crossover between the proteins involved in the different types of dementia. Additionally, CSF sampling makes these biomarkers challenging for presymptomatic identification. We need to focus on disease-specific protein fragmentation to find a fragment pattern unique for each separate dementia type – a form of protein fragmentology. Targeting protein fragments generated by disease-specific combinations of proteins and proteases opposed to detecting the intact protein could reduce the overlap between diagnostic groups as the extent of processing as well as which proteins and proteases constitute the major hallmark of each dementia type differ. In addition, the fragments could be detectable in blood as they may be able to cross the blood–brain barrier due to their smaller size. In this review, the potential of the fragment-based biomarker discovery for dementia diagnosis and prognosis is discussed, especially highlighting how the knowledge from CSF protein biomarkers can be used to guide blood-based biomarker development.
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Affiliation(s)
- Dilek Inekci
- Nordic Bioscience, Biomarkers and Research , Herlev , Denmark ; Systems Biology, Technical University of Denmark , Lyngby , Denmark
| | | | - Sophie Kennard
- Nordic Bioscience, Biomarkers and Research , Herlev , Denmark
| | | | - Kim Henriksen
- Nordic Bioscience, Biomarkers and Research , Herlev , Denmark
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194
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Mizuguchi C, Hata M, Dhanasekaran P, Nickel M, Okuhira K, Phillips MC, Lund-Katz S, Saito H. Fluorescence study of domain structure and lipid interaction of human apolipoproteins E3 and E4. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1841:1716-24. [PMID: 25281910 DOI: 10.1016/j.bbalip.2014.09.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 09/06/2014] [Accepted: 09/24/2014] [Indexed: 12/19/2022]
Abstract
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.
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195
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APOE polymorphisms contribute to reduced atorvastatin response in Chilean Amerindian subjects. Int J Mol Sci 2015; 16:7890-9. [PMID: 25860945 PMCID: PMC4425056 DOI: 10.3390/ijms16047890] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 04/03/2015] [Accepted: 04/03/2015] [Indexed: 11/17/2022] Open
Abstract
Genetic factors can determine the high variability observed in response to lipid-lowering therapy with statins. Nonetheless, the frequency of single nucleotide polymorphisms (SNPs) and their impact can vary due to ethnicity. Because the Chilean population carries a strong Amerindian background, the objective of this study was to evaluate the influence of apolipoprotein E (APOE) variants (rs429358, rs7412) and the 1959C>T SNP (rs5925) in the low-density lipoprotein receptor (LDLR) in response to atorvastatin treatment in hypercholesterolemic individuals. A hundred and thirty nine subjects undergoing statin therapy were included. Identification of Amerindian mtDNA haplogroups was determined by polymerase chain reaction (PCR) and PCR followed by restriction fragment length polymorphism (RFLP), respectively. SNPs were determined by PCR-RFLP. Out of the 139 individuals studied, 84.4% had an Amerindian background, according to mtDNA analysis. In relation to APOE variants, carriers of the E3/4 genotype presented lower cholesterol reduction compared to genotype E3/3 (LDL-C: -18% vs. -29%, p ˂ 0.001). On the other hand, the LDLR rs5925 SNP was not related to atorvastatin response (p = 0.5760). Our results suggest that APOE SNPs are potential predictors to atorvastatin therapy in Amerindian Chilean subjects.
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196
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Wu L, Snyder M. Impact of allele-specific peptides in proteome quantification. Proteomics Clin Appl 2015; 9:432-6. [PMID: 25676416 DOI: 10.1002/prca.201400126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 01/03/2015] [Accepted: 02/05/2015] [Indexed: 11/06/2022]
Abstract
MS-based proteome technologies have greatly improved our ability to detect and quantify proteomes across various biological samples. High throughput bottom-up proteome profiling in combination with targeted MS method, e.g. SRM assay, is emerging as a powerful approach in the field of biomarker discovery. In the past few years, increasing number of studies have attempted to integrate genomic and proteomic data for biomarker discovery. Here, we describe how allele-specific peptide can be applied in biomarker discovery and their impact in protein quantification.
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Affiliation(s)
- Linfeng Wu
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA; Caprion Proteomics US LLC, Menlo Park, CA, USA
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197
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Zhang X, Lei D, Zhang L, Rames M, Zhang S. A model of lipid-free apolipoprotein A-I revealed by iterative molecular dynamics simulation. PLoS One 2015; 10:e0120233. [PMID: 25793886 PMCID: PMC4368682 DOI: 10.1371/journal.pone.0120233] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 01/29/2015] [Indexed: 01/06/2023] Open
Abstract
Apolipoprotein A-I (apo A-I), the major protein component of high-density lipoprotein, has been proven inversely correlated to cardiovascular risk in past decades. The lipid-free state of apo A-I is the initial stage which binds to lipids forming high-density lipoprotein. Molecular models of lipid-free apo A-I have been reported by methods like X-ray crystallography and chemical cross-linking/mass spectrometry (CCL/MS). Through structural analysis we found that those current models had limited consistency with other experimental results, such as those from hydrogen exchange with mass spectrometry. Through molecular dynamics simulations, we also found those models could not reach a stable equilibrium state. Therefore, by integrating various experimental results, we proposed a new structural model for lipid-free apo A-I, which contains a bundled four-helix N-terminal domain (1–192) that forms a variable hydrophobic groove and a mobile short hairpin C-terminal domain (193–243). This model exhibits an equilibrium state through molecular dynamics simulation and is consistent with most of the experimental results known from CCL/MS on lysine pairs, fluorescence resonance energy transfer and hydrogen exchange. This solution-state lipid-free apo A-I model may elucidate the possible conformational transitions of apo A-I binding with lipids in high-density lipoprotein formation.
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Affiliation(s)
- Xing Zhang
- Department of Applied Physics, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
- Molecular Foundry, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Dongsheng Lei
- Department of Applied Physics, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
- Molecular Foundry, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Lei Zhang
- Molecular Foundry, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Matthew Rames
- Molecular Foundry, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Shengli Zhang
- Department of Applied Physics, Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China
- * E-mail:
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198
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APOEε4 increases trauma induced early apoptosis via reducing delayed rectifier K(+) currents in neuronal/glial co-cultures model. Exp Cell Res 2015; 334:294-300. [PMID: 25773779 DOI: 10.1016/j.yexcr.2015.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 02/28/2015] [Accepted: 03/04/2015] [Indexed: 02/04/2023]
Abstract
Traumatic brain injury (TBI) is a commonly encountered emergency and severe neurosurgical injury. Previous studies have shown that the presence of the apolipoprotein E (APOE) ε4 allele has adverse outcomes across the spectrum of TBI severity. Our objective was to evaluate the effects of APOE alleles on trauma induced early apoptosis via modification of delayed rectifier K(+) current (Ik(DR)) in neuronal/glial co-cultures model. An ex vivo neuronal/glial co-cultures model carrying individual APOE alleles (ε2, ε3, ε4) of mechanical injury was developed. Flow cytometry and patch clamp recording were performed to analyze the correlations among APOE genotypes, early apoptosis and Ik(DR). We found that APOEε4 increased early apoptosis at 24h (p<0.05) compared to the ones transfected with APOEε3 and APOEε2. Noticeably, APOEε4 significantly reduced the amplitude of the Ik(DR) at 24h compared to the APOEε3 and APOEε2 (p<0.05) which exacerbate Ca(2+) influx. This indicates a possible effect of APOEε4 on early apoptosis via inhibiting Ik(DR) following injury which may adversely affect the outcome of TBI.
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199
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Hu J, Liu CC, Chen XF, Zhang YW, Xu H, Bu G. Opposing effects of viral mediated brain expression of apolipoprotein E2 (apoE2) and apoE4 on apoE lipidation and Aβ metabolism in apoE4-targeted replacement mice. Mol Neurodegener 2015; 10:6. [PMID: 25871773 PMCID: PMC4356137 DOI: 10.1186/s13024-015-0001-3] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 01/26/2015] [Indexed: 02/06/2023] Open
Abstract
Background Human apolipoprotein E (apoE) exists in three major isoforms: apoE2, apoE3 and apoE4. In the brain, apoE is produced mostly by astrocytes and transports cholesterol to neurons via apoE receptors. Among the gene alleles encoding the three isoforms, the APOE4 allele is the strongest genetic risk factor for late-onset Alzheimer’s disease (AD), whereas APOE2 is protective. ApoE4 confers a gain of toxic function, a loss of neuroprotective function or a combination of both in AD pathogenesis. Given that therapeutic impacts of modulating apoE expression may be isoform-dependent, we sought to investigate the relationship between overexpressing apoE isoform and apoE-related functions in apoE-targeted replacement (TR) mice. Specifically, apoE isoform expression driven by the astrocyte-specific glial fibrillary acidic protein (GFAP) promoter was built into an adeno-associated virus serotype 8 (AAV8) vector and injected into the ventricles of postnatal day 2 (P2) apoE3-TR or apoE4-TR mice. Upon confirmation of apoE isoform expression, effects on apoE lipidation and the levels of amyloid-β (Aβ) in the brain were assessed. Results AAV8-GFAP-apoE isoforms were specifically expressed in astrocytes throughout all brain regions, which led to overall increased apoE levels in the brain. Viral mediated overexpression of apoE4 in the apoE4-TR background increased poorly-lipidated apoE lipoprotein particles and decreased apoE-associated cholesterol in apoE4-TR mice. Conversely, apoE2 overexpression in apoE4-TR mice enhanced apoE lipidation and associated cholesterol. Furthermore, overexpression of apoE4 elevated the levels of endogenous Aβ, whereas apoE2 overexpression trended to lower endogenous Aβ. Conclusions Overexpression of apoE isoforms induces differential effects in the apoE4-TR background: apoE4 decreases apoE lipidation and enhances Aβ accumulation, whereas apoE2 has the opposite effects. Our findings suggest that increasing apoE2 in APOE4 carriers is a beneficial strategy to treat AD, whereas increasing apoE4 in APOE4 carriers is likely harmful. We have also established novel methods to express apoE isoforms in mouse brain to study apoE-related pathways in AD and related dementia. Electronic supplementary material The online version of this article (doi:10.1186/s13024-015-0001-3) contains supplementary material, which is available to authorized users.
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200
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Liu QN, Lin KZ, Yang LN, Dai LS, Wang L, Sun Y, Qian C, Wei GQ, Liu DR, Zhu BJ, Liu CL. Molecular characterization of an Apolipophorin-III gene from the Chinese oak silkworm, Antheraea pernyi (Lepidoptera: Saturniidae). ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2015; 88:155-167. [PMID: 25348706 DOI: 10.1002/arch.21210] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Apolipophorin-III (ApoLp-III) acts in lipid transport, lipoprotein metabolism, and innate immunity in insects. In this study, an ApoLp-III gene of Antheraea pernyi pupae (Ap-ApoLp-III) was isolated and characterized. The full-length cDNA of Ap-ApoLp-III is 687 bp, including a 5'-untranslated region (UTR) of 40 bp, 3'-UTR of 86 bp and an open reading frame of 561 bp encoding a polypeptide of 186 amino acids that contains an Apolipophorin-III precursor domain (PF07464). The deduced Ap-apoLp-III protein sequence has 68, 59, and 23% identity with its orthologs of Manduca sexta, Bombyx mori, and Aedes aegypti, respectively. Phylogenetic analysis showed that the Ap-apoLp-III was close to that of Bombycoidea. qPCR analysis revealed that Ap-ApoLp-III expressed during the four developmental stages and in integument, fat body, and ovaries. After six types of microorganism infections, expression levels of the Ap-ApoLp-III gene were upregulated significantly at different time points compared with control. RNA interference (RNAi) of Ap-ApoLp-III showed that the expression of Ap-ApoLp-III was significantly downregulated using qPCR after injection of E. coli. We infer that the Ap-ApoLp-III gene acts in the innate immunity of A. pernyi.
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Affiliation(s)
- Qiu-Ning Liu
- College of Life Sciences, Anhui Agricultural University, Hefei, P. R.China
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