1
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Blomgren F, Rodin A, Chrobak W, Pacut DW, Swenson J, Ermilova I. Two statins and cromolyn as possible drugs against the cytotoxicity of Aβ(31-35) and Aβ(25-35) peptides: a comparative study by advanced computer simulation methods. RSC Adv 2022; 12:13352-13366. [PMID: 35520132 PMCID: PMC9066867 DOI: 10.1039/d2ra01963a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 04/19/2022] [Indexed: 11/21/2022] Open
Abstract
In this work, possible effective mechanisms of cromolyn, atorvastatin and lovastatin on the cytotoxicity of Aβ(31-35) and Aβ(25-35) peptides were investigated by classical molecular dynamics and well-tempered metadynamics simulations. The results demonstrate that all the drugs affect the behavior of the peptides, such as their ability to aggregate, and alter their secondary structures and their affinity to a particular drug. Our findings from the computed properties suggest that the best drug candidate is lovastatin. This medicine inhibits peptide aggregation, adsorbs the peptides on the surface of the drug clusters, changes the secondary structure and binds to MET35, which has been seen as the reason for the toxicity of the studied peptide sequences. Moreover, lovastatin is the drug which previously has demonstrated the strongest ability to penetrate the blood-brain barrier and makes lovastatin the most promising medicine among the three investigated drugs. Atorvastatin is also seen as a potential candidate if its penetration through the blood-brain barrier could be improved. Otherwise, its properties are even better than the ones demonstrated by lovastatin. Cromolyn appears to be less interesting as an anti-aggregant from the computational data, in comparison to the two statins.
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Affiliation(s)
- Fredrik Blomgren
- Department of Physics, Chalmers University of Technology Fysikgränd 4 Göteborg 41258 Sweden +46-728487773
| | - Alexander Rodin
- Department of Physics, Chalmers University of Technology Fysikgränd 4 Göteborg 41258 Sweden +46-728487773
| | - Wojciech Chrobak
- Department of Physics, Chalmers University of Technology Fysikgränd 4 Göteborg 41258 Sweden +46-728487773
| | - Dawid Wojciech Pacut
- Department of Physics, Chalmers University of Technology Fysikgränd 4 Göteborg 41258 Sweden +46-728487773
| | - Jan Swenson
- Department of Physics, Chalmers University of Technology Fysikgränd 4 Göteborg 41258 Sweden +46-728487773
| | - Inna Ermilova
- Department of Physics, Chalmers University of Technology Fysikgränd 4 Göteborg 41258 Sweden +46-728487773
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2
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Howitz WJ, Guaglianone G, McKnelly KJ, Haduong K, Ashby SN, Laayouni M, Nowick JS. Macrocyclic Peptides Derived from Familial Alzheimer's Disease Mutants Show Charge-Dependent Oligomeric Assembly and Toxicity. ACS Chem Neurosci 2022; 13:714-720. [PMID: 35191689 PMCID: PMC9042422 DOI: 10.1021/acschemneuro.1c00833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
This work probes the role of charge in the oligomeric assembly, toxicity, and membrane destabilization of a series of peptides derived from Aβ and the E22Q and E22K familial mutants. In the mutant Aβ peptides, an acidic residue (E) is replaced with either a neutral or basic residue (Q or K), thus altering the net charge of the peptide. Acetylation at peripheral positions permits modulation of charge of the peptides and allows investigation of the role of charge in their oligomeric assembly, cytotoxicity, and membrane disruption. Peptides with the same net charge generally behave similarly even if the amino acid residue at position 22 differs. As the net charge of the peptide decreases, so does the extent of assembly, cytotoxicity, and membrane destabilization, which were determined using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, lactate dehydrogenase (LDH)-release assays with SH-SY5Y cells, and dye leakage assays using liposomes. These findings suggest that the charge of the amino acid side chain, rather than its size or hydrophobicity, accounts for the differences in the oligomeric assembly and toxicity of the E22 familial mutants of Aβ.
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Affiliation(s)
- William J Howitz
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Gretchen Guaglianone
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Kate J McKnelly
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Katelyn Haduong
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Shareen N Ashby
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - Mohamed Laayouni
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States
| | - James S Nowick
- Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States.,Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, California 92697, United States
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3
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Kurz C, Walker L, Rauchmann BS, Perneczky R. Dysfunction of the blood-brain barrier in Alzheimer's disease: evidence from human studies. Neuropathol Appl Neurobiol 2021; 48:e12782. [PMID: 34823269 DOI: 10.1111/nan.12782] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 11/04/2021] [Accepted: 11/16/2021] [Indexed: 11/28/2022]
Abstract
The pathological processes leading to synapse loss, neuronal loss, brain atrophy and gliosis in Alzheimer´s disease (AD) and their relation to vascular disease and immunological changes are yet to be fully explored. Amyloid-β (Aβ) aggregation, vascular damage and altered immune response interact at the blood-brain-barrier (BBB), affecting the brain endothelium and fuelling neurodegeneration. The aim of the present systematic literature review was to critically appraise and to summarise the published evidence on the clinical correlations and pathophysiological concepts of BBB damage in AD, focusing on human data. The PubMed, Cochrane, Medline and Embase databases were searched for original research articles, systematic reviews and meta-analyses, published in English language from 01/2000 to 07/2021, using the keywords Alzheimer*, amyloid-β or β-amyloid or abeta and brain-blood barrier or BBB. This review shows that specific changes of intercellular structures, reduced expression of transendothelial carriers, induction of vasoactive mediators and activation of both astroglia and monocytes/macrophages characterise blood-brain barrier damage in human AD and AD models. BBB dysfunction on magnetic resonance imaging takes place early in the disease course in AD-specific brain regions. The toxic effects of Aβ and apolipoprotein E (ApoE) are likely to induce a non-cerebral-amyloid-angiopathy-related degeneration of endothelial cells, independently of cerebrovascular disease; however, some of the observed structural changes may just arise with age. Small vessel disease, ApoE, loss of pericytes, pro-inflammatory signalling and cerebral amyloid angiopathy enhance blood-brain-barrier damage. Novel therapeutic approaches for AD, including magnetic resonance-guided focused ultrasound, aim to open the BBB, potentially leading to an improved drainage of Aβ along perivascular channels and increased elimination from the brain. In vitro treatments with ApoE-modifying agents yielded promising effects on modulating BBB function. Reducing cardiovascular risk factors represents one of the most promising interventions for dementia prevention at present. However, further research is needed to elucidate the connection of BBB damage and tau pathology, the role of pro-inflammatory mediators in draining macromolecules and cells from the cerebral parenchyma, including their contribution to cerebral amyloid angiopathy. Improved insight into these pathomechanisms may allow to shed light on the role of Aβ deposition as a primary vs. a secondary event in the complex pathogenesis of AD.
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Affiliation(s)
- Carolin Kurz
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany
| | - Lauren Walker
- Translational and Clinical Research Institute, Campus for Ageing and Vitality, Newcastle University
| | - Boris-Stephan Rauchmann
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany.,Department of Radiology, Department of Radiology, University Hospital, LMU Munich, Munich, Germany
| | - Robert Perneczky
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany.,German Center for Neurodegenerative Disorders (DZNE) Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Ageing Epidemiology (AGE) Research Unit, School of Public Health, Imperial College London, London, UK
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4
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Chrobak W, Pacut DW, Blomgren F, Rodin A, Swenson J, Ermilova I. Component of Cannabis, Cannabidiol, as a Possible Drug against the Cytotoxicity of Aβ(31-35) and Aβ(25-35) Peptides: An Investigation by Molecular Dynamics and Well-Tempered Metadynamics Simulations. ACS Chem Neurosci 2021; 12:660-674. [PMID: 33544587 PMCID: PMC8023578 DOI: 10.1021/acschemneuro.0c00692] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/01/2021] [Indexed: 12/14/2022] Open
Abstract
In this work cannabidiol (CBD) was investigated as a possible drug against the cytotoxicity of Aβ(31-35) and Aβ(25-35) peptides with the help of atomistic molecular dynamics (MD) and well-tempered metadynamics simulations. Four interrelated mechanisms of possible actions of CBD are proposed from our computations. This implies that one mechanism can be a cause or/and a consequence of another. CBD is able to decrease the aggregation of peptides at certain concentrations of compounds in water. This particular action is more prominent for Aβ(25-35), since originally Aβ(31-35) did not exhibit aggregation properties in aqueous solutions. Interactions of CBD with the peptides affect secondary structures of the latter ones. Clusters of CBD are seen as possible adsorbents of Aβ(31-35) and Aβ(25-35) since peptides are tending to aggregate around them. And last but not least, CBD exhibits binding to MET35. All four mechanisms of actions can possibly inhibit the Aβ-cytotoxicity as discussed in this paper. Moreover, the amount of water also played a role in peptide clustering: with a growing concentration of peptides in water without a drug, the aggregation of both Aβ(31-35) and Aβ(25-35) increased. The number of hydrogen bonds between peptides and water was significantly higher for simulations with Aβ(25-35) at the higher concentration of peptides, while for Aβ(31-35) that difference was rather insignificant. The presence of CBD did not substantially affect the number of hydrogen bonds in the simulated systems.
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Affiliation(s)
| | | | | | | | - Jan Swenson
- Department of Physics, Chalmers
University of Technology, 412 96 Gothenburg, Sweden
| | - Inna Ermilova
- Department of Physics, Chalmers
University of Technology, 412 96 Gothenburg, Sweden
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5
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Shi H, Koronyo Y, Rentsendorj A, Regis GC, Sheyn J, Fuchs DT, Kramerov AA, Ljubimov AV, Dumitrascu OM, Rodriguez AR, Barron E, Hinton DR, Black KL, Miller CA, Mirzaei N, Koronyo-Hamaoui M. Identification of early pericyte loss and vascular amyloidosis in Alzheimer's disease retina. Acta Neuropathol 2020; 139:813-836. [PMID: 32043162 PMCID: PMC7181564 DOI: 10.1007/s00401-020-02134-w] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/17/2020] [Accepted: 02/02/2020] [Indexed: 01/27/2023]
Abstract
Pericyte loss and deficient vascular platelet-derived growth factor receptor-β (PDGFRβ) signaling are prominent features of the blood-brain barrier breakdown described in Alzheimer's disease (AD) that can predict cognitive decline yet have never been studied in the retina. Recent reports using noninvasive retinal amyloid imaging, optical coherence tomography angiography, and histological examinations support the existence of vascular-structural abnormalities and vascular amyloid β-protein (Aβ) deposits in retinas of AD patients. However, the cellular and molecular mechanisms of such retinal vascular pathology were not previously explored. Here, by modifying a method of enzymatically clearing non-vascular retinal tissue and fluorescent immunolabeling of the isolated blood vessel network, we identified substantial pericyte loss together with significant Aβ deposition in retinal microvasculature and pericytes in AD. Evaluation of postmortem retinas from a cohort of 56 human donors revealed an early and progressive decrease in vascular PDGFRβ in mild cognitive impairment (MCI) and AD compared to cognitively normal controls. Retinal PDGFRβ loss significantly associated with increased retinal vascular Aβ40 and Aβ42 burden. Decreased vascular LRP-1 and early apoptosis of pericytes in AD retina were also detected. Mapping of PDGFRβ and Aβ40 levels in pre-defined retinal subregions indicated that certain geometrical and cellular layers are more susceptible to AD pathology. Further, correlations were identified between retinal vascular abnormalities and cerebral Aβ burden, cerebral amyloid angiopathy (CAA), and clinical status. Overall, the identification of pericyte and PDGFRβ loss accompanying increased vascular amyloidosis in Alzheimer's retina implies compromised blood-retinal barrier integrity and provides new targets for AD diagnosis and therapy.
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Affiliation(s)
- Haoshen Shi
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, CA, 90048, USA
| | - Yosef Koronyo
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, CA, 90048, USA
| | - Altan Rentsendorj
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, CA, 90048, USA
| | - Giovanna C Regis
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, CA, 90048, USA
| | - Julia Sheyn
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, CA, 90048, USA
| | - Dieu-Trang Fuchs
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, CA, 90048, USA
| | - Andrei A Kramerov
- Department of Biomedical Sciences and Eye Program, Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Alexander V Ljubimov
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, CA, 90048, USA
- Department of Biomedical Sciences and Eye Program, Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Biomedical Sciences, Division of Applied Cell Biology and Physiology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Oana M Dumitrascu
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Anthony R Rodriguez
- Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - David R Hinton
- Departments of Pathology and Ophthalmology, Keck School of Medicine, USC Roski Eye Institute, University of Southern California, Los Angeles, CA, USA
| | - Keith L Black
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, CA, 90048, USA
| | - Carol A Miller
- Department of Pathology Program in Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Nazanin Mirzaei
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, CA, 90048, USA
| | - Maya Koronyo-Hamaoui
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, 127 S. San Vicente Blvd., Los Angeles, CA, 90048, USA.
- Department of Biomedical Sciences, Division of Applied Cell Biology and Physiology, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
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6
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Jäkel L, Biemans EA, Klijn CJ, Kuiperij HB, Verbeek MM. Reduced Influence of apoE on Aβ43 Aggregation and Reduced Vascular Aβ43 Toxicity as Compared with Aβ40 and Aβ42. Mol Neurobiol 2020; 57:2131-2141. [PMID: 31953617 PMCID: PMC7118029 DOI: 10.1007/s12035-020-01873-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/07/2020] [Indexed: 01/08/2023]
Abstract
The amyloid-β 43 (Aβ43) peptide has been shown to be abundantly expressed in Alzheimer's disease plaques, whereas only relatively low levels have been demonstrated in cerebral amyloid angiopathy (CAA). To better understand this discrepant distribution, we studied various biochemical properties of Aβ43, in comparison with Aβ40 and Aβ42. We assessed the interaction of Aβ43 with the three apoE isoforms (apoE2, apoE3, and apoE4) using SDS-PAGE/Western blotting and ELISA, aggregation propensity using thioflavin T assays, and cytotoxicity towards cerebrovascular cells using MTT assays. We found that Aβ43 did not differ from Aβ42 in its interaction with apoE, whereas Aβ40 had a significantly lower degree of interaction with apoE. At a molar ratio of 1:100 (apoE:Aβ), all apoE isoforms were comparably capable of inhibiting aggregation of Aβ40 and Aβ42, but not Aβ43. All Aβ variants had a concentration-dependent negative effect on metabolic activity of cerebrovascular cells. However, the degree of this effect differed for the three Aβ isoforms (Aβ40 > Aβ42 > Aβ43), with Aβ43 being the least cytotoxic peptide towards cerebrovascular cells. We conclude that Aβ43 has different biochemical characteristics compared with Aβ40 and Aβ42. Aggregation of Aβ43 is not inhibited by apoE, in contrast to the aggregation of Aβ40 and Aβ42. Furthermore, cerebrovascular cells are less sensitive towards Aβ43, compared with Aβ40 and Aβ42. In contrast, Aβ43 neither differed from Aβ42 in its aggregation propensity (in the absence of apoE) nor in its apoE-binding capacity. Altogether, our findings may provide an explanation for the lower levels of Aβ43 accumulation in cerebral vessel walls.
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Affiliation(s)
- Lieke Jäkel
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Elisanne A.L.M. Biemans
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Catharina J.M. Klijn
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
| | - H. Bea Kuiperij
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marcel M. Verbeek
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Neurology, Radboud University Medical Center, 830 TML, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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7
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Mudedla SK, Murugan NA, Ågren H. Effect of Familial Mutations on the Interconversion of α-Helix to β-Sheet Structures in an Amyloid-Forming Peptide: Insight from Umbrella Sampling Simulations. ACS Chem Neurosci 2019; 10:1347-1354. [PMID: 30586502 DOI: 10.1021/acschemneuro.8b00425] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Understanding the initial events of aggregation of amyloid β monomers to form β-sheet rich fibrils is useful for the development of therapeutics for Alzheimer's disease. In this context, the changes in energetics involved in the aggregation of helical amyloid β monomers into β-sheet rich dimers have been investigated using umbrella sampling simulations and density functional theory calculations. The results from umbrella sampling simulations for the free energy profile for the interconversion closely agree with the results of density functional theory calculations. The results reveal that helical peptides converted to β-sheet structures through coil-like conformations as intermediates that are mostly stabilized by intramolecular hydrogen bonds. The stabilization of intermediate structures could be a possible way to inhibit fibril formation. Mutations substantially decrease the height of the energy barrier for interconversion from α-helix to β-sheet structure when compared to that of the wild type, something that is attributed to an increase in the number of intramolecular hydrogen bonds between backbone atoms in the coil structures that correspond to a maximum value on the free energy surface. The reduction of the energy barrier leads to an enhancement of the rate of aggregation of amyloid β monomers upon introduction of various familial mutations, which is consistent with previous experimental reports.
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Affiliation(s)
- Sathish Kumar Mudedla
- Division of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, AlbaNova University Center, Royal Institute of Technology (KTH), S-106 91 Stockholm, Sweden
| | - N. Arul Murugan
- Division of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, AlbaNova University Center, Royal Institute of Technology (KTH), S-106 91 Stockholm, Sweden
| | - Hans Ågren
- Division of Theoretical Chemistry and Biology, School of Engineering Sciences in Chemistry, Biotechnology and Health, AlbaNova University Center, Royal Institute of Technology (KTH), S-106 91 Stockholm, Sweden
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, P. R. China
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8
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Paik S, Somvanshi RK, Kumar U. Somatostatin Maintains Permeability and Integrity of Blood-Brain Barrier in β-Amyloid Induced Toxicity. Mol Neurobiol 2018; 56:292-306. [PMID: 29700775 DOI: 10.1007/s12035-018-1045-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 03/27/2018] [Indexed: 12/11/2022]
Abstract
In Alzheimer's disease (AD), the impaired clearance of β-amyloid peptide (Aβ) due to disrupted tight junction and transporter proteins is the prominent cause of disease progression. Somatostatin (SST) blocks the aggregation of Aβ and inflammation whereas reduction of SST levels in the CSF and brain tissue is associated with impaired cognitive function and memory loss. However, the role of SST in preservation of blood-brain barrier (BBB) integrity and functionality in Aβ-induced toxicity is not known. In the present study using human CMEC/D3 cells, we demonstrate that SST prevents Aβ-induced BBB permeability by regulating LRP1 and RAGE expression and improving the disrupted tight junction proteins. Furthermore, SST abrogates Aβ-induced JNK phosphorylation and expression of MMP2. Taken together, results presented here suggest that SST might serve as a therapeutic intervention in AD via targeting multiple pathways responsible for neurotoxicity, impaired BBB function, and disease progression.
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Affiliation(s)
- Seungil Paik
- Faculty of Pharmaceutical Sciences, The University of British Columbia, V6T1Z3, Vancouver, BC, Canada
| | - Rishi K Somvanshi
- Faculty of Pharmaceutical Sciences, The University of British Columbia, V6T1Z3, Vancouver, BC, Canada
| | - Ujendra Kumar
- Faculty of Pharmaceutical Sciences, The University of British Columbia, V6T1Z3, Vancouver, BC, Canada.
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9
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Vascular protective effects of KLF2 on Aβ-induced toxicity: Implications for Alzheimer’s disease. Brain Res 2017; 1663:174-183. [DOI: 10.1016/j.brainres.2017.01.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 12/29/2016] [Accepted: 01/02/2017] [Indexed: 11/19/2022]
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10
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Greco S, Zaccagnini G, Fuschi P, Voellenkle C, Carrara M, Sadeghi I, Bearzi C, Maimone B, Castelvecchio S, Stellos K, Gaetano C, Menicanti L, Martelli F. Increased BACE1-AS long noncoding RNA and β-amyloid levels in heart failure. Cardiovasc Res 2017; 113:453-463. [DOI: 10.1093/cvr/cvx013] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 01/25/2017] [Indexed: 01/18/2023] Open
Affiliation(s)
- Simona Greco
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | - Germana Zaccagnini
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | - Paola Fuschi
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | - Christine Voellenkle
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | - Matteo Carrara
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | - Iman Sadeghi
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | - Claudia Bearzi
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council of Italy (CNR), Monterotondo Scalo, Rome, Italy
| | - Biagina Maimone
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | | | - Konstantinos Stellos
- Laboratory of RNA Metabolism and Vascular Inflammation, Institute of Cardiovascular Regeneration, Centre of Molecular Medicine, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Carlo Gaetano
- Division of Cardiovascular Epigenetics, Department of Cardiology and Internal Medicine Clinic III, Department of Cardiology, Goethe University, Frankfurt/Main, Germany
| | - Lorenzo Menicanti
- Department of Cardiac Surgery, IRCCS Policlinico San Donato, Milan, Italy
| | - Fabio Martelli
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
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11
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Real-time monitoring of amyloid growth in a rigid gel matrix. Anal Biochem 2016; 511:13-6. [DOI: 10.1016/j.ab.2016.07.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 07/21/2016] [Accepted: 07/26/2016] [Indexed: 11/22/2022]
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12
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Kuan WL, Bennett N, He X, Skepper JN, Martynyuk N, Wijeyekoon R, Moghe PV, Williams-Gray CH, Barker RA. α-Synuclein pre-formed fibrils impair tight junction protein expression without affecting cerebral endothelial cell function. Exp Neurol 2016; 285:72-81. [PMID: 27632900 DOI: 10.1016/j.expneurol.2016.09.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/01/2016] [Accepted: 09/11/2016] [Indexed: 12/17/2022]
Abstract
Recently it has been shown that there is impaired cerebral endothelial function in many chronic neurodegenerative disorders including Alzheimer's and Huntington's disease. Such problems have also been reported in Parkinson's disease, in which α-synuclein aggregation is the pathological hallmark. However, little is known about the relationship between misfolded α-synuclein and endothelial function. In the present study, we therefore examined whether α-synuclein preformed fibrils affect endothelial function in vitro. Using a well-established endothelial cell model, we found that the expression of tight junction proteins, in particular zona occludens-1 and occludin, was significantly perturbed in the presence of fibril-seeded neurotoxicity. Disrupted expression of these proteins was also found in the postmortem brains of patients dying with Parkinson's disease. There was though little evidence in vitro of functional impairments in endothelial cell function in terms of transendothelial electrical resistance and permeability. This study therefore shows for the first time that misfolded α-synuclein can interact and affect the cerebral endothelial system, although its relevance to the pathogenesis of Parkinson's disease remains to be elucidated.
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Affiliation(s)
- Wei-Li Kuan
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Forvie Site, Robinson Way, Cambridge CB2 0PY, United Kingdom.
| | - Neal Bennett
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Forvie Site, Robinson Way, Cambridge CB2 0PY, United Kingdom; Department of Biomedical Engineering, Rutgers University, Piscataway, NJ, United States
| | - Xiaoling He
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Forvie Site, Robinson Way, Cambridge CB2 0PY, United Kingdom
| | - Jeremy N Skepper
- Cambridge Advanced Imaging Centre, Department of Physiology, Development and Neuroscience, Anatomy Building, University of Cambridge, Downing Street, Cambridge CB2 3DY, United Kingdom
| | - Nataly Martynyuk
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Forvie Site, Robinson Way, Cambridge CB2 0PY, United Kingdom
| | - Ruwani Wijeyekoon
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Forvie Site, Robinson Way, Cambridge CB2 0PY, United Kingdom
| | - Prabhas V Moghe
- Department of Biomedical Engineering, Rutgers University, Piscataway, NJ, United States; Department of Chemical & Biochemical Engineering, Rutgers University, Piscataway, NJ, United States
| | - Caroline H Williams-Gray
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Forvie Site, Robinson Way, Cambridge CB2 0PY, United Kingdom
| | - Roger A Barker
- John van Geest Centre for Brain Repair and Department of Clinical Neuroscience, University of Cambridge, Forvie Site, Robinson Way, Cambridge CB2 0PY, United Kingdom; Department of Neurology, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom
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Griffin JM, Kho D, Graham ES, Nicholson LFB, O’Carroll SJ. Statins Inhibit Fibrillary β-Amyloid Induced Inflammation in a Model of the Human Blood Brain Barrier. PLoS One 2016; 11:e0157483. [PMID: 27309956 PMCID: PMC4911157 DOI: 10.1371/journal.pone.0157483] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 05/31/2016] [Indexed: 02/03/2023] Open
Abstract
Background Astrocytes and cerebral endothelial cells are important components of the blood-brain barrier (BBB). Disruption to this barrier through inflammation is a major contributor to Alzheimer’s disease (AD) pathology. The amyloid beta (Aβ) protein is known to exist in several forms and is a key modulator of AD that is known to cause inflammation and changes to BBB function. While one of these forms, fibrillary Aβ (fAβ), is known to cause endothelial cell death at the BBB, no studies have looked specifically at its role on inflammation in a model of the human BBB. Aims To determine if fAβ is inflammatory to the human BBB. As statins have been shown to be anti-inflammatory and protective in AD, we also tested if these could inhibit the inflammatory effect of fAβ. Methods Using cultured cerebral endothelial cells and astrocytes we determined changes in cytokine release, cell toxicity and barrier function in response to fibrillary β-amyloid1–42 (fAβ1–42) alone and in combination with statins. Results fAβ1–42 induced inflammatory cytokine release from endothelial cells in the absence of cell toxicity. It also induced astrocyte cytokine release and cell death and caused a loss of barrier integrity. Statin treatment inhibited all of these effects. Conclusions We conclude that fAβ1–42 has both inflammatory and cytotoxic effects on the BBB and the protective effect of statins in AD may in part be through inhibiting these effects.
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Affiliation(s)
- Jarred M. Griffin
- Centre for Brain Research, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Dan Kho
- Centre for Brain Research, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - E. Scott Graham
- Centre for Brain Research, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Louise F. B. Nicholson
- Centre for Brain Research, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Simon J. O’Carroll
- Centre for Brain Research, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Department of Anatomy and Medical Imaging, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- * E-mail:
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Kase CS, Shoamanesh A, Greenberg SM, Caplan LR. Intracerebral Hemorrhage. Stroke 2016. [DOI: 10.1016/b978-0-323-29544-4.00028-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
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15
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Differential contribution of isoaspartate post-translational modifications to the fibrillization and toxic properties of amyloid β and the Asn23 Iowa mutation. Biochem J 2015; 456:347-60. [PMID: 24028142 DOI: 10.1042/bj20130652] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mutations within the Aβ (amyloid β) peptide, especially those clustered at residues 21-23, are linked to early-onset AD (Alzheimer's disease) and primarily associated with cerebral amyloid angiopathy. The Iowa variant, a substitution of an aspartic acid residue for asparagine at position 23 (D23N), associates with widespread vascular amyloid and abundant diffuse pre-amyloid lesions significantly exceeding the incidence of mature plaques. Brain Iowa deposits consist primarily of a mixture of mutated and non-mutated Aβ species exhibiting partial aspartate isomerization at positions 1, 7 and 23. The present study analysed the contribution of the post-translational modification and the D23N mutation to the aggregation/fibrillization and cell toxicity properties of Aβ providing insight into the elicited cell death mechanisms. The induction of apoptosis by the different Aβ species correlated with their oligomerization/fibrillization propensity and β-sheet content. Although cell toxicity was primarily driven by the D23N mutation, all Aβ isoforms tested were capable, albeit at different time frames, of eliciting comparable apoptotic pathways with mitochondrial engagement and cytochrome c release to the cytoplasm in both neuronal and microvascular endothelial cells. Methazolamide, a cytochrome c release inhibitor, exerted a protective effect in both cell types, suggesting that pharmacological targeting of mitochondria may constitute a viable therapeutic avenue.
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BDNF prevents amyloid-dependent impairment of LTP in the entorhinal cortex by attenuating p38 MAPK phosphorylation. Neurobiol Aging 2014; 36:1303-9. [PMID: 25554494 DOI: 10.1016/j.neurobiolaging.2014.11.016] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 10/24/2014] [Accepted: 11/25/2014] [Indexed: 12/18/2022]
Abstract
The oligomeric form of the amyloid peptide Aβ(1-42) is capable of perturbing synaptic plasticity in different brain areas. Here, we evaluated the protective role of brain-derived neurotrophic factor (BDNF) in beta amyloid (Aβ)-dependent impairment of long-term potentiation in entorhinal cortex (EC) slices. We found that BDNF (1 ng/mL) supplied by perfusion was able to rescue long-term potentiation in Aβ(1-42)-treated slices; BDNF protection was mediated by TrkB receptor as assessed by using the tyrosine kinase inhibitor K252a (200 nM). We also investigated the function of endogenous BDNF using a soluble form of TrkB receptor (TrkB IgG). Incubation of slices with TrkB IgG (1 μg/mL) increased the EC vulnerability to Aβ. Finally, we investigated the effect of BDNF on the cell stress-kinase p38 mitogen-activated protein kinase (MAPK) in primary cortical cell cultures exposed to Aβ(1-42). We found that Aβ induces p38 MAPK phosphorylation, although pretreatment with BDNF prevented Aβ-dependent p38 MAPK phosphorylation. This result was confirmed by an immunoassay in tissue extracts from EC slices collected after electrophysiology.
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Yan J, Liu Q, Dou Y, Hsieh Y, Liu Y, Tao R, Zhu D, Lou Y. Activating glucocorticoid receptor-ERK signaling pathway contributes to ginsenoside Rg1 protection against β-amyloid peptide-induced human endothelial cells apoptosis. JOURNAL OF ETHNOPHARMACOLOGY 2013; 147:456-466. [PMID: 23538162 DOI: 10.1016/j.jep.2013.03.039] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 03/10/2013] [Accepted: 03/11/2013] [Indexed: 06/02/2023]
Abstract
The deposition of β-amyloid (Aβ) in neurons and vascular cells of the brain has been characterized in Alzheimer's disease. Ginsenoside Rg1 (Rg1) is an active components in Panax ginseng, a famous traditional Chinese medicines recorded in Compendium of Materia Medica. Present study attempted to evaluate the potential mechanisms of Aβ-mediated insult and the protective effects of Rg1 on human endothelial cells. Rg1 attenuated the Aβ25-35-associated mitochondrial apoptotic events, accompanied by inhibiting HIF-1α expression followed by intracellular reactive nitrogen species generation, and protein nitrotyrosination. These protective effects were abolished by glucocorticoid receptor (GR) antagonist RU486 or p-ERK inhibitor U0126 rather than estrogen receptor α antagonist ICI 82,780. Taken together, our results suggested that Rg1 protected against Aβ25-35-induced apoptosis at least in part by two complementary GR-dependent ERK phosphorylation pathways: (1) down-regulating HIF-1α initiated protein nitrotyrosination, and (2) inhibiting mitochondrial apoptotic cascades. These data provided a novel insight to the mechanisms of Rg1protective effects on Aβ25-35-induced endothelial cells apoptosis, suggesting that GR-ERK signaling pathway might play an important role in it.
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Affiliation(s)
- Jieping Yan
- Institute of Pharmacology, Toxicology and Biochemical Pharmaceutics, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
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18
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Enhanced Aβ(1-40) production in endothelial cells stimulated with fibrillar Aβ(1-42). PLoS One 2013; 8:e58194. [PMID: 23505467 PMCID: PMC3591408 DOI: 10.1371/journal.pone.0058194] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 02/04/2013] [Indexed: 12/25/2022] Open
Abstract
Amyloid accumulation in the brain of Alzheimer’s patients results from altered processing of the 39- to 43-amino acid amyloid β protein (Aβ). The mechanisms for the elevated amyloid (Aβ1–42) are considered to be over-expression of the amyloid precursor protein (APP), enhanced cleavage of APP to Aβ, and decreased clearance of Aβ from the central nervous system (CNS). We report herein studies of Aβ stimulated effects on endothelial cells. We observe an interesting and as yet unprecedented feedback effect involving Aβ1–42 fibril-induced synthesis of APP by Western blot analysis in the endothelial cell line Hep-1. We further observe an increase in the expression of Aβ1–40 by flow cytometry and fluorescence microscopy. This phenomenon is reproducible for cultures grown both in the presence and absence of serum. In the former case, flow cytometry reveals that Aβ1–40 accumulation is less pronounced than under serum-free conditions. Immunofluorescence staining further corroborates these observations. Cellular responses to fibrillar Aβ1–42 treatment involving eNOS upregulation and increased autophagy are also reported.
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Cruz L, Rao JS, Teplow DB, Urbanc B. Dynamics of metastable β-hairpin structures in the folding nucleus of amyloid β-protein. J Phys Chem B 2012; 116:6311-25. [PMID: 22587454 PMCID: PMC3394227 DOI: 10.1021/jp301619v] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The amyloid β-protein (Aβ), which is present predominately as a 40- or 42-residue peptide, is postulated to play a seminal role in the pathogenesis of Alzheimer's disease (AD). Folding of the Aβ(21-30) decapeptide region is a critical step in the aggregation of Aβ. We report results of constant temperature all-atom molecular dynamics simulations in explicit water of the dynamics of monomeric Aβ(21-30) and its Dutch [Glu22Gln], Arctic [Glu22Gly], and Iowa [Asp23Asn] isoforms that are associated with familial forms of cerebral amyloid angiopathy and AD. The simulations revealed a variety of loop conformers that exhibited a hydrogen bond network involving the Asp23 and Ser26 amino acids. A population of conformers, not part of the loop population, was found to form metastable β-hairpin structures with the highest probability in the Iowa mutant. At least three β-hairpin structures were found that differed in their hydrogen bonding register, average number of backbone hydrogen bonds, and lifetimes. Analysis revealed that the Dutch mutant had the longest β-hairpin lifetime (≥500 ns), closely followed by the Iowa mutant (≈500 ns). Aβ(21-30) and the Arctic mutant had significantly lower lifetimes (≈200 ns). Hydrophobic packing of side chains was responsible for enhanced β-hairpin lifetimes in the Dutch and Iowa mutants, whereas lifetimes in Aβ(21-30) and its Arctic mutant were influenced by the backbone hydrogen bonding. The data suggest that prolonged β-hairpin lifetimes may impact peptide pathogenicity in vivo.
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Affiliation(s)
- L Cruz
- Department of Physics, 3141 Chestnut Street, Drexel University, Philadelphia, Pennsylvania 19104, United States.
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20
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Carrano A, Hoozemans JJM, van der Vies SM, Rozemuller AJM, van Horssen J, de Vries HE. Amyloid Beta induces oxidative stress-mediated blood-brain barrier changes in capillary amyloid angiopathy. Antioxid Redox Signal 2011; 15:1167-78. [PMID: 21294650 DOI: 10.1089/ars.2011.3895] [Citation(s) in RCA: 215] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cerebral amyloid angiopathy (CAA) is frequently observed in Alzheimer's disease (AD) and is characterized by deposition of amyloid beta (Aβ) in leptomeningeal and cortical brain vasculature. In 40% of AD cases, Aβ mainly accumulates in cortical capillaries, a phenomenon referred to as capillary CAA (capCAA). The aim of this study was to investigate blood-brain barrier (BBB) alterations in CAA-affected capillaries with the emphasis on tight junction (TJ) changes. First, capCAA brain tissue was analyzed for the distribution of TJs. Here, we show for the first time a dramatic loss of occludin, claudin-5, and ZO-1 in Aβ-laden capillaries surrounded by NADPH oxidase-2 (NOX-2)-positive activated microglia. Importantly, we observed abundant vascular expression of the Aβ transporter receptor for advanced glycation endproducts (RAGE). To unravel the underlying mechanism, a human brain endothelial cell line was stimulated with Aβ1-42 to analyze the effects of Aβ. We observed a dose-dependent cytotoxicity and increased ROS generation, which interestingly was reversed by administration of exogenous antioxidants, NOX-2 inhibitors, and by blocking RAGE. Taken together, our data evidently show that Aβ is toxic to brain endothelial cells via binding to RAGE and induction of ROS production, which ultimately leads to disruption of TJs and loss of BBB integrity.
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Affiliation(s)
- Anna Carrano
- Department of Molecular Cell Biology and Immunology (MCBI), VU University Medical Center, Amsterdam, The Netherlands.
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21
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Kase CS, Greenberg SM, Mohr J, Caplan LR. Intracerebral Hemorrhage. Stroke 2011. [DOI: 10.1016/b978-1-4160-5478-8.10029-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Chen X, Ghribi O, Geiger JD. Caffeine protects against disruptions of the blood-brain barrier in animal models of Alzheimer's and Parkinson's diseases. J Alzheimers Dis 2010; 20 Suppl 1:S127-41. [PMID: 20164568 DOI: 10.3233/jad-2010-1376] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Sporadic Alzheimer's disease (AD) and Parkinson's disease (PD) are two of the most common neurodegenerative diseases and as such they represent major public health problems. Finding effective treatments for AD and PD represents an unmet and elusive goal largely because these diseases are chronic and progressive, and have a complicated and ill-understood pathogenesis. Although the underlying mechanisms are not fully understood, caffeine, the most commonly ingested psychoactive drug in the world, has been shown in human and animal studies to be protective against AD and PD. One mechanism implicated in the pathogenesis of AD and PD is blood-brain barrier (BBB) dysfunction and we reported recently that caffeine exerts protective effects against AD and PD at least in part by keeping the BBB intact. The present review focuses on the role of BBB dysfunction in the pathogenesis of AD and PD, caffeine's protective effects against AD and PD, and potential mechanisms whereby caffeine protects against BBB leakage.
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Affiliation(s)
- Xuesong Chen
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, USA
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23
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Hernandez-Guillamon M, Mawhirt S, Fossati S, Blais S, Pares M, Penalba A, Boada M, Couraud PO, Neubert TA, Montaner J, Ghiso J, Rostagno A. Matrix metalloproteinase 2 (MMP-2) degrades soluble vasculotropic amyloid-beta E22Q and L34V mutants, delaying their toxicity for human brain microvascular endothelial cells. J Biol Chem 2010; 285:27144-27158. [PMID: 20576603 PMCID: PMC2930713 DOI: 10.1074/jbc.m110.135228] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 06/21/2010] [Indexed: 11/06/2022] Open
Abstract
Patients carrying mutations within the amyloid-beta (Abeta) sequence develop severe early-onset cerebral amyloid angiopathy with some of the related variants manifesting primarily with hemorrhagic phenotypes. Matrix metalloproteases (MMPs) are typically associated with blood brain barrier disruption and hemorrhagic transformations after ischemic stroke. However, their contribution to cerebral amyloid angiopathy-related hemorrhage remains unclear. Human brain endothelial cells challenged with Abeta synthetic homologues containing mutations known to be associated in vivo with hemorrhagic manifestations (AbetaE22Q and AbetaL34V) showed enhanced production and activation of MMP-2, evaluated via Multiplex MMP antibody arrays, gel zymography, and Western blot, which in turn proteolytically cleaved in situ the Abeta peptides. Immunoprecipitation followed by mass spectrometry analysis highlighted the generation of specific C-terminal proteolytic fragments, in particular the accumulation of Abeta-(1-16), a result validated in vitro with recombinant MMP-2 and quantitatively evaluated using deuterium-labeled internal standards. Silencing MMP-2 gene expression resulted in reduced Abeta degradation and enhanced apoptosis. Secretion and activation of MMP-2 as well as susceptibility of the Abeta peptides to MMP-2 degradation were dependent on the peptide conformation, with fibrillar elements of AbetaE22Q exhibiting negligible effects. Our results indicate that MMP-2 release and activation differentially degrades Abeta species, delaying their toxicity for endothelial cells. However, taking into consideration MMP ability to degrade basement membrane components, these protective effects might also undesirably compromise blood brain barrier integrity and precipitate a hemorrhagic phenotype.
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Affiliation(s)
- Mar Hernandez-Guillamon
- Neurovascular Research Laboratory, Institut de Recerca, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain
| | - Stephanie Mawhirt
- Department of Pathology, New York University School of Medicine, New York, New York 10016
| | - Silvia Fossati
- Department of Pathology, New York University School of Medicine, New York, New York 10016
| | - Steven Blais
- Department of Pharmacology, , New York University School of Medicine, New York, New York 10016; Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, New York 10016
| | - Mireia Pares
- Neurovascular Research Laboratory, Institut de Recerca, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain
| | - Anna Penalba
- Neurovascular Research Laboratory, Institut de Recerca, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain
| | - Merce Boada
- Neurovascular Unit, Department of Neurology, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain
| | | | - Thomas A Neubert
- Department of Pharmacology, , New York University School of Medicine, New York, New York 10016; Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, New York 10016
| | - Joan Montaner
- Neurovascular Research Laboratory, Institut de Recerca, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; Neurovascular Unit, Department of Neurology, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain
| | - Jorge Ghiso
- Department of Pathology, New York University School of Medicine, New York, New York 10016; Department of Psychiatry, New York University School of Medicine, New York, New York 10016
| | - Agueda Rostagno
- Department of Pathology, New York University School of Medicine, New York, New York 10016.
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Soluble amyloid-beta, effect on cerebral arteriolar regulation and vascular cells. Mol Neurodegener 2010; 5:15. [PMID: 20388225 PMCID: PMC2873254 DOI: 10.1186/1750-1326-5-15] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 04/13/2010] [Indexed: 12/22/2022] Open
Abstract
Background Evidence indicates that soluble forms of amyloid-β (Aβ) are vasoactive, which may contribute to cerebrovascular dysfunction noted in patients with Alzheimer's Disease and cerebral amyloid angiopathy. The effects of soluble Aβ on penetrating cerebral arterioles - the vessels most responsible for controlling cerebrovascular resistance - have not been studied. Results Freshly dissolved Aβ1-40 and Aβ1-42, but not the reverse peptide Aβ40-1 constricted isolated rat penetrating arterioles and diminished dilation to adenosine tri-phosphate (ATP). Aβ1-42 also enhanced ATP-induced vessel constriction. Aβ1-40 diminished arteriolar myogenic response, and an anti-Aβ antibody reduced Aβ1-40 induced arteriolar constriction. Prolonged Aβ exposure in vessels of Tg2576 mice resulted in a marked age-dependent effect on ATP-induced vascular responses. Vessels from 6 month old Tg2576 mice had reduced vascular responses whereas these were absent from 12 month old animals. Aβ1-40 and Aβ1-42 acutely increased production of reactive oxygen species (ROS) in cultured rat cerebro-microvascular cells. The radical scavenger MnTBAP attenuated this Aβ-induced oxidative stress and Aβ1-40-induced constriction in rat arterioles. Conclusions Our results suggest that soluble Aβ1-40 and Aβ1-42 directly affect the vasomotor regulation of isolated rodent penetrating arterioles, and that ROS partially mediate these effects. Once insoluble Aβ deposits are present, arteriolar reactivity is greatly diminished.
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Origlia N, Arancio O, Domenici L, Yan SS. MAPK, beta-amyloid and synaptic dysfunction: the role of RAGE. Expert Rev Neurother 2010; 9:1635-45. [PMID: 19903023 DOI: 10.1586/ern.09.107] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Genetic and biological studies provide strong support for the hypothesis that accumulation of beta amyloid peptide (Abeta) contributes to the etiology of Alzheimer's disease (AD). Growing evidence indicates that oligomeric soluble Abeta plays an important role in the development of synaptic dysfunction and the impairment of cognitive function in AD. The receptor for advanced glycation end products (RAGE), a multiligand receptor in the immunoglobulin superfamily, acts as a cell surface binding site for Abeta and mediates alternations in the phosphorylation state of mitogen-activated protein kinase (MAPKs). Recent results have shown that MAPKs are involved in neurodegenerative processes. In particular, changes in the phosphorylation state of various MAPKs by Abeta lead to synaptic dysfunction and cognitive decline, as well as development of inflammatory responses in AD. The present review summarizes the evidence justifying a novel therapeutic approach focused on inhibition of RAGE signaling in order to arrest or halt the development of neuronal dysfunction in AD.
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Kassler K, Horn AHC, Sticht H. Effect of pathogenic mutations on the structure and dynamics of Alzheimer’s Aβ42-amyloid oligomers. J Mol Model 2009; 16:1011-20. [DOI: 10.1007/s00894-009-0611-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Accepted: 10/01/2009] [Indexed: 10/20/2022]
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Viana RJS, Nunes AF, Castro RE, Ramalho RM, Meyerson J, Fossati S, Ghiso J, Rostagno A, Rodrigues CMP. Tauroursodeoxycholic acid prevents E22Q Alzheimer's Abeta toxicity in human cerebral endothelial cells. Cell Mol Life Sci 2009; 66:1094-104. [PMID: 19189048 PMCID: PMC2760857 DOI: 10.1007/s00018-009-8746-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The vasculotropic E22Q mutant of the amyloid-beta (Abeta) peptide is associated with hereditary cerebral hemorrhage with amyloidosis Dutch type. The cellular mechanism(s) of toxicity and nature of the AbetaE22Q toxic assemblies are not completely understood. Comparative assessment of structural parameters and cell death mechanisms elicited in primary human cerebral endothelial cells by AbetaE22Q and wild-type Abeta revealed that only AbetaE22Q triggered the Bax mitochondrial pathway of apoptosis. AbetaE22Q neither matched the fast oligomerization kinetics of Abeta42 nor reached its predominant beta-sheet structure, achieving a modest degree of oligomerization with a secondary structure that remained a mixture of beta and random conformations. The endogenous molecule tauroursodeoxycholic acid (TUDCA) was a strong modulator of AbetaE22Q-triggered apoptosis but did not significantly change the secondary structures and fibrillogenic propensities of Abeta peptides. These data dissociate the pro-apoptotic properties of Abeta peptides from their distinct mechanisms of aggregation/fibrillization in vitro, providing new perspectives for modulation of amyloid toxicity.
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Affiliation(s)
- R. J. S. Viana
- iMed.UL, Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, Lisbon, 1649–019 Portugal
| | - A. F. Nunes
- iMed.UL, Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, Lisbon, 1649–019 Portugal
| | - R. E. Castro
- iMed.UL, Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, Lisbon, 1649–019 Portugal
| | - R. M. Ramalho
- iMed.UL, Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, Lisbon, 1649–019 Portugal
| | - J. Meyerson
- Department of Pathology, New York University School of Medicine, New York, New York USA
| | - S. Fossati
- Department of Pathology, New York University School of Medicine, New York, New York USA
| | - J. Ghiso
- Department of Pathology, New York University School of Medicine, New York, New York USA
- Department of Psychiatry, New York University School of Medicine, New York, New York USA
| | - A. Rostagno
- Department of Pathology, New York University School of Medicine, New York, New York USA
| | - C. M. P. Rodrigues
- iMed.UL, Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, Lisbon, 1649–019 Portugal
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Solito R, Corti F, Fossati S, Mezhericher E, Donnini S, Ghiso J, Giachetti A, Rostagno A, Ziche M. Dutch and Arctic mutant peptides of beta amyloid(1-40) differentially affect the FGF-2 pathway in brain endothelium. Exp Cell Res 2008; 315:385-95. [PMID: 19061884 DOI: 10.1016/j.yexcr.2008.11.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 09/25/2008] [Accepted: 11/04/2008] [Indexed: 11/27/2022]
Abstract
Single point mutations of the amyloid precursor protein generate Abeta variants bearing amino acid substitutions at positions 21-23. These mutants are associated with distinct hereditary phenotypes of cerebral amyloid angiopathy, manifesting varying degrees of tropism for brain vessels, and impaired microvessel remodeling and angiogenesis. We examined the differential effects of E22Q (Dutch), and E22G (Arctic) variants in comparison to WT Abeta on brain endothelial cell proliferation, angiogenic phenotype expression triggered by fibroblast growth factor (FGF-2), pseudo-capillary sprouting, and induction of apoptosis. E22Q exhibited a potent anti-angiogenic profile in contrast to E22G, which had a much weaker effect. Investigations on the FGF-2 signaling pathway revealed the greatest differences among the peptides: E22Q and WT peptides suppressed FGF-2 expression while E22G had barely any effect. Phosphorylation of the FGF-2 receptor, FGFR-1, and the survival signal Akt were abolished by E22Q and WT peptides, but not by E22G. The biological dissimilar effect of the mutant and WT peptides on cerebral EC cannot be assigned to a particular Abeta structure, suggesting that the toxic effect of the Abeta assemblies goes beyond mere multimerization.
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Affiliation(s)
- Raffaella Solito
- Department of Molecular Biology, University of Siena, Via A. Moro 2, 53100, Siena, Italy
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Receptor for advanced glycation end product-dependent activation of p38 mitogen-activated protein kinase contributes to amyloid-beta-mediated cortical synaptic dysfunction. J Neurosci 2008; 28:3521-30. [PMID: 18367618 DOI: 10.1523/jneurosci.0204-08.2008] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Soluble amyloid-beta (Abeta) peptide is likely to play a key role during early stages of Alzheimer's disease (AD) by perturbing synaptic function and cognitive processes. Receptor for advanced glycation end products (RAGE) has been identified as a receptor involved in Abeta-induced neuronal dysfunction. We investigated the role of neuronal RAGE in Abeta-induced synaptic dysfunction in the entorhinal cortex, an area of the brain important in memory processes that is affected early in AD. We found that soluble oligomeric Abeta peptide (Abeta42) blocked long-term potentiation (LTP), but did not affect long-term depression, paired-pulse facilitation, or basal synaptic transmission. In contrast, Abeta did not inhibit LTP in slices from RAGE-null mutant mice or in slices from wild-type mice treated with anti-RAGE IgG. Similarly, transgenic mice expressing a dominant-negative form of RAGE targeted to neurons showed normal LTP in the presence of Abeta, suggesting that neuronal RAGE functions as a signal transducer for Abeta-mediated LTP impairment. To investigate intracellular pathway transducing RAGE activation by Abeta, we used inhibitors of stress activated kinases. We found that inhibiting p38 mitogen-activated protein kinase (p38 MAPK), but not blocking c-Jun N-terminal kinase activation, was capable of maintaining LTP in Abeta-treated slices. Moreover, Abeta-mediated enhancement of p38 MAPK phosphorylation in cortical neurons was reduced by blocking antibodies to RAGE. Together, our results indicate that Abeta impairs LTP in the entorhinal cortex through neuronal RAGE-mediated activation of p38 MAPK.
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30
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Han F, Ali Raie A, Shioda N, Qin ZH, Fukunaga K. Accumulation of beta-amyloid in the brain microvessels accompanies increased hyperphosphorylated tau proteins following microsphere embolism in aged rats. Neuroscience 2008; 153:414-27. [PMID: 18400410 DOI: 10.1016/j.neuroscience.2008.02.044] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 02/12/2008] [Accepted: 02/13/2008] [Indexed: 11/19/2022]
Abstract
To define mechanisms underlying neurovascular injury following brain embolism-induced neurodegeneration, we investigated temporal and spatial pathological changes in brain microvessels up to 12 weeks after microsphere embolism (ME) induction in aged male rats. Mild ME upregulated endothelial nitric oxide synthase (eNOS) and protein tyrosine nitration in brain microvessels. Strong beta-amyloid immunoreactivity coincident with increased eNOS immunoreactivity was observed in microvessels. Immunoblotting of purified brain microvessels revealed that beta-amyloid accumulation significantly increased 1 week after ME induction and remained elevated for 12 weeks. Importantly, beta-amyloid accumulation in brain parenchyma was also observed in areas surrounding injured microvessels at 12 weeks. Levels of Alzheimer's-related hyperphosphorylated tau proteins also concomitantly increased in neurons surrounding regions of beta-amyloid accumulation 12 weeks after ME induction, as did glycogen synthase kinase (GSK3beta) (Tyr-216) phosphorylation. Taken together, ME-induced aberrant eNOS expression and subsequent protein tyrosine nitration in microvessels preceded beta-amyloid accumulation both in microvessels and brain parenchyma, leading to hyperphosphorylation of neuronal tau proteins through GSK3beta activation.
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Affiliation(s)
- F Han
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki-Aoba Aoba-ku, Sendai 980-8578, Japan
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31
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Abstract
Alzheimer's disease (AD) is a complex disorder of the central nervous system (CNS). Molecular genetic research has provided a wealth of information regarding the genetic etiology of this devastating disease. Identification and functional characterization of autosomal dominant mutations in the amyloid precursor protein gene (APP) and the presenilin genes 1 and 2 (PSEN1 and PSEN2) have contributed substantially to our understanding of the biological mechanisms leading towards CNS neurodegeneration in AD. Nonetheless, a large part of the genetic etiology remains unresolved, especially that of more common, sporadic forms of AD. While substantial efforts were invested in the identification of genetic risk factors underlying sporadic AD, using carefully designed genetic association studies in large patient-control groups, the only firmly established risk factor remains the epsilon4 allele of the apolipoprotein E gene (APOE). Nevertheless, one can expect that with the current availability of high-throughput genotyping platforms and dense maps of single-nucleotide polymorphisms (SNPs), large-scale genetic studies will eventually generate additional knowledge about the genetic risk profile for AD. This review provides an overview of the current understanding in the field of AD genetics, covering both the rare monogenic forms as well as recent developments in the search for novel AD susceptibility genes.
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Affiliation(s)
- Nathalie Brouwers
- Neurodegenerative Brain Diseases Group, Department of Molecular Genetics, VIB, Antwerpen, Belgium
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32
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Ionov ID. Specific mechanism for blood inflow stimulation in brain area prone to Alzheimer's disease lesions. Int J Neurosci 2007; 117:1425-42. [PMID: 17729154 DOI: 10.1080/00207450601125733] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The present study describes the specific two-stage mechanism that intensifies blood supply to the brain area comprising amygdala, hippocampus, olfactory bulb, entorhinal cortex, and neocortex (AHBC). Cholinergic neurons from the nuclei of basal forebrain induce vasodilatory effect through release of acetylcholine. In physiological aging the efficacy of this neuronal system declines, while intensive formation of amyloidogenic peptides starts. These peptides at low, picomolar concentrations activate alpha7 nicotinic acetylcholine receptors, thus enhancing angiogenesis and in so doing restoring blood supply to the AHBC area.
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Affiliation(s)
- Ilya D Ionov
- Center on Theoretical Problems in Physicochemical Pharmacology, Russian Academy of Sciences, Moscow, Russia.
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33
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Gonzalez-Velasquez FJ, Moss MA. Soluble aggregates of the amyloid-beta protein activate endothelial monolayers for adhesion and subsequent transmigration of monocyte cells. J Neurochem 2007; 104:500-13. [PMID: 17953673 DOI: 10.1111/j.1471-4159.2007.04988.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Increasing evidence suggests that the deposition of amyloid plaques, composed primarily of the amyloid-beta protein (Abeta), within the cerebrovasculature is a frequent occurrence in Alzheimer's disease and may play a significant role in disease progression. Accordingly, the pathogenic mechanisms by which Abeta can alter vascular function may have therapeutic implications. Despite observations that Abeta elicits a number of physiological responses in endothelial cells, ranging from alteration of protein expression to cell death, the Abeta species accountable for these responses remains unexplored. In the current study, we show that isolated soluble Abeta aggregation intermediates activate human brain microvascular endothelial cells for both adhesion and subsequent transmigration of monocyte cells in the absence of endothelial cell death and monolayer disruption. In contrast, unaggregated Abeta monomer and mature Abeta fibril fail to induce any change in endothelial adhesion or transmigration. Correlations between average Abeta aggregate size and observed increases in adhesion illustrate that smaller soluble aggregates are more potent activators of endothelium. These results support previous studies demonstrating heightened neuronal activity of soluble Abeta aggregates, including Abeta-derived diffusible ligands, oligomers, and protofibrils, and further show that soluble aggregates also selectively exhibit activity in a vascular cell model.
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Affiliation(s)
- Francisco J Gonzalez-Velasquez
- Department of Chemical Engineering, University of South Carolina, Swearingen Engineering Center, Columbia, South Carolina 29208, USA
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34
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Herzig MC, Van Nostrand WE, Jucker M. Mechanism of cerebral beta-amyloid angiopathy: murine and cellular models. Brain Pathol 2006; 16:40-54. [PMID: 16612981 PMCID: PMC8095938 DOI: 10.1111/j.1750-3639.2006.tb00560.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cerebral amyloid angiopathy of the beta-amyloid type (Abeta-CAA) is a risk factor for hemorrhagic stroke and independently is believed to contribute to dementia. Naturally occurring animal models of Abeta-CAA are scarce and not well suited for the laboratory. To this end, a variety of transgenic mouse models have been developed that, similar to cerebral Abeta-amyloidosis in humans, develop either Abeta-CAA only or both Abeta-CAA and parenchymal amyloid, or primarily parenchymal amyloid with only scarce Abeta-CAA. The lessons learned from these mouse models are: i) Abeta-CAA alone is sufficient to induce cerebral hemorrhage and associate pathologies including neuroinflammation, ii) the origin of vascular amyloid is mainly neuronal, iii) Abeta-CAA results largely from impaired Abeta clearance, iv) a high ratio Abeta40:42 favors vascular over parenchymal amyloidosis, and v) genetic risk factors such as ApoE modulate Abeta-CAA and CAA-induced hemorrhages. Therapeutic strategies to inhibit Abeta-CAA are poor at the present time. Once Abeta-CAA is present current Abeta immunotherapy strategies have failed to clear vascular amyloid and even run the risk of serious side effects. Despite this progress in deciphering the pathomechanism of Abeta-CAA, with these first generation mouse models of Abeta-CAA, refining these models is needed and will help to understand the emerging importance of Abeta-CAA for dementia and to develop biomarkers and therapeutic strategies.
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Affiliation(s)
- Martin C. Herzig
- Department of Cellular Neurology, Hertie‐Institute for Clinical Brain Research, University of Tübingen, Germany
- Department of Neuropathology, Institute of Pathology, University of Basel, Switzerland
| | | | - Mathias Jucker
- Department of Cellular Neurology, Hertie‐Institute for Clinical Brain Research, University of Tübingen, Germany
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Haglund M, Kalaria R, Slade JY, Englund E. Differential deposition of amyloid beta peptides in cerebral amyloid angiopathy associated with Alzheimer's disease and vascular dementia. Acta Neuropathol 2006; 111:430-5. [PMID: 16555084 DOI: 10.1007/s00401-006-0054-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2005] [Revised: 02/08/2006] [Accepted: 02/09/2006] [Indexed: 10/24/2022]
Abstract
Cerebral amyloid angiopathy (CAA) caused by deposition of amyloid beta (Abeta) peptides in the cerebrovasculature, involves degeneration of normal vascular components and increases the risk of infarction and cerebral hemorrhage. Accumulating evidence suggests that sporadic CAA is also a significant contributor to cognitive decline and dementia in the elderly. However, the mechanisms by which CAA arises are poorly understood. While neuronal sources of Abeta peptides are sufficient to cause CAA in transgenic mice overexpressing the amyloid precursor protein, there is reason to believe that in aging man, vascular disease modulates the disease process. To better understand CAA mechanisms in dementia, we assessed the frontal cortex of 62 consecutive cases of Alzheimer's disease (AD), vascular dementia (VaD), and mixed dementia (MD) using immunohistochemistry with antibodies to Abeta, smooth muscle actin and the carboxyl-terminal peptides to detect Abeta(40) and Abeta(42). While vascular Abeta deposition was invariably associated with smooth muscle degeneration as indicated by absence of smooth muscle cell actin reactivity, VaD/MD cases exhibited markedly more vascular Abeta(42) deposits and smooth muscle actin loss compared to AD cases with similar degrees of CAA and Abeta(40) deposition. This suggests that distinct mechanisms are responsible for the differential deposition of Abeta in CAA associated with AD and that associated with ischemic/cerebrovascular disease. It is plausible that experimental studies on the effects of cerebrovascular disease on Abeta production and elimination will yield important clues on the pathogenesis of CAA.
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Affiliation(s)
- Mattias Haglund
- Division of Neuropathology, Department of Pathology and Cytology, Lund University Hospital, 221 85, Lund, Sweden.
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36
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Marco S, Skaper SD. Amyloid beta-peptide1-42 alters tight junction protein distribution and expression in brain microvessel endothelial cells. Neurosci Lett 2006; 401:219-24. [PMID: 16644119 DOI: 10.1016/j.neulet.2006.03.047] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Revised: 03/08/2006] [Accepted: 03/09/2006] [Indexed: 11/24/2022]
Abstract
Alzheimer's disease is characterised by neuronal loss, numerous intraneuronal deposits of neurofibrillary tangles, senile plaques, and cerebrovascular amyloid deposits. The major component of senile plaques and cerebrovascular deposits is the 39-43 amino acid beta-amyloid peptide (Abeta). The effects of Abeta on cerebral endothelium and thus the blood-brain barrier remain unclear. Utilising endothelial cells isolated from rat cerebral cortex microvessels, we have examined effects of Abeta peptides on tight junction protein behaviour. The transmembrane tight junction proteins occludin, claudin-1 and claudin-5, as well as the cytoplasmic accessory proteins ZO-1 and ZO-2 displayed a continuous distribution at cell boundaries. Endothelial cells exposed to Abeta1-42 (20 microM) for 3 days showed a disrupted plasma membrane pattern of claudin-5 and ZO-2 with relocation to the cytoplasm. These effects were not seen with Abeta25-35 or Abeta1-40[Gln22] (Dutch type). Abeta1-42 treatment altered also protein expression: occludin was lower at 1st day, claudin-1 increased at all times, and ZO-2 increased after 1 day and then decreased. These data suggest that Abeta1-42 effects on tight junction protein complexes may alter blood-brain barrier integrity and contribute to the neuropathological sequelae of Alzheimer's disease.
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Affiliation(s)
- Sonia Marco
- Neurology and GI Centre of Excellence for Drug Discovery, GlaxoSmithKline Research and Development Limited, New Frontiers Science Park, Third Avenue, CM19 5AW Harlow, Essex, United Kingdom
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37
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Magrane J, Christensen RA, Rosen KM, Veereshwarayya V, Querfurth HW. Dissociation of ERK and Akt signaling in endothelial cell angiogenic responses to beta-amyloid. Exp Cell Res 2006; 312:996-1010. [PMID: 16427623 DOI: 10.1016/j.yexcr.2005.12.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2005] [Revised: 11/08/2005] [Accepted: 12/13/2005] [Indexed: 02/05/2023]
Abstract
Cerebrovascular deposits of beta-amyloid (Abeta) peptides are found in Alzheimer's disease and cerebral amyloid angiopathy with stroke or dementia. Dysregulations of angiogenesis, the blood-brain barrier and other critical endothelial cell (EC) functions have been implicated in aggravating chronic hypoperfusion in AD brain. We have used cultured ECs to model the effects of beta-amyloid on the activated phosphorylation states of multifunctional serine/threonine kinases since these are differentially involved in the survival, proliferation and migration aspects of angiogenesis. Serum-starved EC cultures containing amyloid-beta peptides underwent a 2- to 3-fold increase in nuclear pyknosis. Under growth conditions with sublethal doses of beta-amyloid, loss of cell membrane integrity and inhibition of cell proliferation were observed. By contrast, cell migration was the most sensitive to Abeta since inhibition was significant already at 1 muM (P = 0.01, migration vs. proliferation). In previous work, intracellular Abeta accumulation was shown toxic to ECs and Akt function. Here, extracellular Abeta peptides do not alter Akt activation, resulting instead in proportionate decreases in the phosphorylations of the MAPKs: ERK1/2 and p38 (starting at 1 microM). This inhibitory action occurs proximal to MEK1/2 activation, possibly through interference with growth factor receptor coupling. Levels of phospho-JNK remained unchanged. Addition of PD98059, but not LY294002, resulted in a similar decrease in activated ERK1/2 levels and inhibition of EC migration. Transfection of ERK1/2 into Abeta-poisoned ECs functionally rescued migration. The marked effect of extracellular Abeta on the migration component of angiogenesis is associated with inhibition of MAPK signaling, while Akt-dependent cell survival appears more affected by cellular Abeta.
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Affiliation(s)
- Jordi Magrane
- Department of Neurology, Caritas St. Elizabeth's Medical Center and Tufts University School of Medicine, Boston, MA 02135, USA
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38
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Ujiie M, Dickstein DL, Carlow DA, Jefferies WA. Blood-brain barrier permeability precedes senile plaque formation in an Alzheimer disease model. Microcirculation 2004; 10:463-70. [PMID: 14745459 DOI: 10.1038/sj.mn.7800212] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2002] [Accepted: 02/10/2003] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To establish the generality of cerebrovascular pathology frequently observed with Alzheimer disease, we have assessed blood-brain barrier (BBB) integrity using the Alzheimer disease model Tg2576 mice in which cognitive deficits and neuritic plaque formation develop around 10-12 months of age. METHODS We assessed BBB integrity using well-established methods involving albumin and Evans blue uptake and introduce the use of a novel perfusion protocol using succinimidyl ester of carboxyfluorescein diacetate. RESULTS BBB permeability is increased in the cerebral cortex of 10-month-old Tg2576 mice preceding Alzheimer disease pathology presentation. Furthermore, when compared with their nontransgenic littermates, 4-month-old Tg2576 mice exhibit compromised BBB integrity in some areas of the cerebral cortex. An age-related increase in albumin uptake by the brains of Tg2576 mice, compared with nontransgenic mice, was also observed. These findings were supported by quantitative Evans blue analysis (p = 0.07, two-way analysis of variance). CONCLUSION A breakdown of BBB was evident in young 4- to 10-month-old Tg2576 mice. Compromised barrier function could explain the mechanisms of Abeta entry into the brain observed in experimental Alzheimer disease vaccination models. Such structural changes to the BBB caused by elevated Abeta could play a central role in Alzheimer disease development and might define an early point of intervention for designing effective therapy against the disease.
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Affiliation(s)
- Maki Ujiie
- Biotechnology Laboratory, University of British Columbia, Vancouver V6T 1Z3, Canada
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39
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McCarron MO, Nicoll JAR. Cerebral amyloid angiopathy and thrombolysis-related intracerebral haemorrhage. Lancet Neurol 2004; 3:484-92. [PMID: 15261609 DOI: 10.1016/s1474-4422(04)00825-7] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Intracerebral haemorrhage is a complication of thrombolytic therapy for acute myocardial infarction, pulmonary embolism, and ischaemic stroke. There is increasing evidence that cerebral amyloid angiopathy (CAA), which itself can cause haemorrhage (CAAH), may be a risk factor for thrombolysis-related intracerebral haemorrhage. CAAH and thrombolysis-related intracerebral haemorrhage share some clinical features, such as predisposition to lobar or superficial regions of the brain, multiple haemorrhages, increasing frequency with age, and an association with dementia. In vitro work showed that accumulation of amyloid-beta peptide causes degeneration of cells in the walls of blood vessels, affects vasoactivity, and improves proteolytic mechanisms, such as fibrinolysis, anticoagulation, and degradation of the extracellular matrix. In a mouse model of CAA there is a low haemorrhagic threshold after thrombolytic therapy compared with that in wild-type mice. To date only a small number of anecdotal clinicopathological relations have been reported; neuroimaging advances and further study of the frequency and role of CAA in patients with thrombolysis-related intracerebral haemorrhage are required.
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Affiliation(s)
- Mark O McCarron
- Department of Neurology, Altnagelvin Hospital, Londonderry, BT47 6SB, UK.
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40
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Abstract
Cerebral amyloid angiopathy (CAA) is the result of the deposition of an amyloidogenic protein in cortical and leptomeningeal vessels. The most common type of CAA is caused by amyloid beta-protein (Abeta), which is particularly associated with Alzheimer's disease (AD). Excessive Abeta-CAA formation can be caused by several mutations in the Abeta precursor protein and presenilin genes. The origin of Abeta in CAA is likely to be neuronal, although cerebrovascular cells or the circulation cannot be excluded as a source. Despite the apparent similarity, the pathogenesis of CAA appears to differ from that of senile plaques in several aspects, including the mechanism of Abeta-induced cellular toxicity, the extent of inflammatory reaction and the role of oxidative stress. Therefore, therapeutic strategies for AD should, at least in part, also target CAA. Moreover, CAA and cerebrovascular disease (CVD) may set a lower threshold for AD-like changes to cause dementia and may even cause dementia on its own, since patients with AD and CAA and/or CVD appear to be more cognitively impaired than patients with only AD. In conclusion, the precise impact of CAA on AD or dementia remains unclear, however, its role may have been underestimated in the past, and more extensive studies of in vitro and in vivo models for CAA will be needed to elucidate the importance of CAA-specific approaches in designing intervention strategies for AD.
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Affiliation(s)
- Annemieke A M Rensink
- Department of Neurology, Laboratory of Pediatrics and Neurology, University Medical Center, 319, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
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42
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Abstract
A remarkable rise in life expectancy during the past century has made Alzheimer's disease (AD) the most common form of progressive cognitive failure in humans. Compositional analyses of the classical brain lesions, the senile (amyloid) plaques and neurofibrillary tangles, preceded and has guided the search for genetic alterations. Four genes have been unequivocally implicated in inherited forms of AD, and mutations or polymorphisms in these genes cause excessive cerebral accumulation of the amyloid beta-protein and subsequent neuronal and glial pathology in brain regions important for memory and cognition. This understanding of the genotype-to-phenotype conversions of familial AD has led to the development of pharmacological strategies to lower amyloid beta-protein levels as a way of treating or preventing all forms of the disease.
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Affiliation(s)
- Dennis J Selkoe
- Center for Neurologic Diseases, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
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43
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Abstract
Genetic studies of primary intracerebral hemorrhage (PICH) have begun to yield important biologic insights into the pathogenesis of this disorder. This review of candidate genes for PICH emphasizes the value of focusing on individual pathogenic phenotypes. One type of PICH in particular, cerebral amyloid angiopathy, is known to have specific genetic factors regulating both its familial and sporadic forms. Another promising research method is to focus on pathways involved in hemostasis that may be etiologically relevant to all types of PICH. Genetic studies will improve our understanding of the biology of PICH, and may eventually be incorporated into clinical decision making regarding anticoagulation.
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Affiliation(s)
- Steven M Greenberg
- Neurology Clinical Trials Unit, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA.
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44
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Abstract
Cerebral amyloid angiopathy (CAA), defined by deposition of the beta-amyloid peptide in medium and small cortical and meningeal vessels, is a well-recognized cause of hemorrhagic stroke. This paper reviews the accumulating evidence supporting an additional role for CAA in producing vessel dysfunction, reduced cerebral blood flow and ischemia. Ischemic lesions are characteristic of several hereditary CAA syndromes, including a recently described mutation of the amyloid precursor protein associated with dementia (but not hemorrhagic stroke) in an Iowa family. Ischemic lesions are seen in some sporadic CAA patients as well, and recent data from transgenic mice suggest potential mechanisms by which beta-amyloid may alter vessel physiology. Future studies will seek to define the clinical importance of vascular beta-amyloid as a potential target for drug therapy in dementia.
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Affiliation(s)
- Steven M Greenberg
- Department of Neurology, Massachusetts General Hospital, Boston, Mass 02114, USA.
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45
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Familial amyloid polyneuropathy: receptor for advanced glycation end products-dependent triggering of neuronal inflammatory and apoptotic pathways. J Neurosci 2001. [PMID: 11567048 DOI: 10.1523/jneurosci.21-19-07576.2001] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Familial amyloid polyneuropathy (FAP) is a neurodegenerative disorder associated with extracellular deposition of mutant transthyretin (TTR) amyloid fibrils, particularly in the peripheral nervous system. We have hypothesized that binding of TTR fibrils to the receptor for advanced glycation end products (RAGE) on critical cellular targets is associated with a destructive stress response underlying peripheral nerve dysfunction. Analysis of nerve biopsy samples from patients with FAP (n = 16) at different stages of disease (0-3), compared with age-matched controls (n = 4), by semiquantitative immunohistology and in situ hybridization showed increased levels of RAGE, beginning at the earliest stages of the disease (FAP 0; p < 0.02) and especially localized in axons. Upregulation of proinflammatory cytokines (tumor necrosis factor-alpha and interleukin-1beta) (approximately threefold; p < 0.02) and the inducible form of nitric oxide synthase (iNOS) ( approximately 2.5-fold; p < 0.04) was also observed in a distribution overlapping RAGE expression. Tyrosine nitration and increased activated caspase-3 in axons from FAP patients (p < 0.03) were apparent. Although these data suggest the presence of ongoing neuronal stress, there was no upregulation of neurotrophins (nerve growth factor and neurotrophin-3) in FAP nerves. Studies on cultured neuronal-like, Schwann, and endothelial cells incubated with TTR fibrils displayed RAGE-dependent expression of cytokines and iNOS at early times (6 and 12 hr, respectively), followed by later (24 hr) activation of caspase-3 and DNA fragmentation. We propose that the interaction of TTR fibrils with RAGE may contribute to cellular stress and toxicity in FAP. Furthermore, there is an apparent lack of responsiveness of Schwann cells in FAP nerve to provide neurotrophic factors.
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Van Nostrand WE, Melchor JP, Cho HS, Greenberg SM, Rebeck GW. Pathogenic effects of D23N Iowa mutant amyloid beta -protein. J Biol Chem 2001; 276:32860-6. [PMID: 11441013 DOI: 10.1074/jbc.m104135200] [Citation(s) in RCA: 197] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cerebral amyloid beta-protein angiopathy (CAA) is a key pathological feature of patients with Alzheimer's disease and certain related disorders. In these conditions the CAA is characterized by the deposition of Abeta within the cerebral vessel wall and, in severe cases, hemorrhagic stroke. Several mutations have been identified within the Abeta region of the Abeta protein precursor (AbetaPP) gene that appear to enhance the severity of CAA. We recently described a new mutation within the Abeta region (D23N) of AbetaPP that is associated with severe CAA in an Iowa kindred (Grabowski, T. J., Cho, H. S., Vonsattel, J. P. G., Rebeck, G. W., and Greenberg, S. M. (2001) Ann. Neurol. 49, 697-705). In the present study, we investigated the effect of this new D23N mutation on the processing of AbetaPP and the pathogenic properties of Abeta. Neither the D23N Iowa mutation nor the E22Q Dutch mutation affected the amyloidogenic processing of AbetaPP expressed in H4 cells. The A21G Flemish mutation, in contrast, resulted in a 2.3-fold increase in secreted Abeta peptide. We also tested synthetic wild-type and mutant Abeta40 peptides for fibrillogenesis and toxicity toward cultured human cerebrovascular smooth muscle (HCSM) cells. The E22Q Dutch, D23N Iowa, and E22Q,D23N Dutch/Iowa double mutant Abeta40 peptides rapidly assembled in solution to form fibrils, whereas wild-type and A21G Flemish Abeta40 peptides exhibited little fibril formation. Similarly, the E22Q Dutch and D23N Iowa Abeta40 peptides were found to induce robust pathologic responses in cultured HCSM cells, including elevated levels of cell-associated AbetaPP, proteolytic breakdown of smooth muscle cell alpha-actin, and cell death. Double mutant E22Q,D23N Dutch/Iowa Abeta40 was more potent than either single mutant form of Abeta in causing pathologic responses in HCSM cells. These data suggest that the different CAA mutations in AbetaPP may exert their pathogenic effects through different mechanisms. Whereas the A21G Flemish mutation appears to enhance Abeta production, the E22Q Dutch and D23N Iowa mutations enhance fibrillogenesis and the pathogenicity of Abeta toward HCSM cells.
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Affiliation(s)
- W E Van Nostrand
- Departments of Medicine and Pathology, Health Sciences Center, State University of New York, Stony Brook, NY 11794-8153, USA.
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47
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Zurdo J, Guijarro JI, Jiménez JL, Saibil HR, Dobson CM. Dependence on solution conditions of aggregation and amyloid formation by an SH3 domain. J Mol Biol 2001; 311:325-40. [PMID: 11478864 DOI: 10.1006/jmbi.2001.4858] [Citation(s) in RCA: 182] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The formation of amyloid fibrils by the SH3 domain of the alpha-subunit of bovine phosphatidylinositol-3'-kinase (PI3-SH3) has been investigated under carefully controlled solution conditions. NMR and CD characterisation of the denatured states from which fibrils form at low pH show that their properties can be correlated with the nature of the resulting aggregates defined by EM and FTIR spectroscopy. Compact partially folded states, favoured by the addition of anions, are prone to precipitate rapidly into amorphous species, whilst well-defined fibrillar structures are formed slowly from more expanded denatured states. Kinetic data obtained by a variety of techniques show a clear lag phase in the formation of amyloid fibrils. NMR spectroscopy shows no evidence for a significant population of small oligomers in solution during or after this lag phase. EM and FTIR indicate the presence of amorphous aggregates (protofibrils) rich in beta-structure after the lag phase but prior to the development of well-defined amyloid fibrils. These observations strongly suggest a nucleation and growth mechanism for the formation of the ordered aggregates. The morphologies of the fibrillar structures were found to be highly sensitive to the pH at which the protein solutions are incubated. This can be attributed to the effect of small perturbations in the electrostatic interactions that stabilise the contacts between the protofilaments forming the amyloid fibrils. Moreover, different hydrogen bonding patterns related to the various aggregate morphologies can be distinguished by FTIR analysis.
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Affiliation(s)
- J Zurdo
- Oxford Centre for Molecular Sciences, New Chemistry Laboratory, South Parks Road, Oxford, OX1 3QH, UK
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48
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Grabowski TJ, Cho HS, Vonsattel JP, Rebeck GW, Greenberg SM. Novel amyloid precursor protein mutation in an Iowa family with dementia and severe cerebral amyloid angiopathy. Ann Neurol 2001; 49:697-705. [PMID: 11409420 DOI: 10.1002/ana.1009] [Citation(s) in RCA: 403] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Several mutations in the amyloid precursor protein (APP) gene have been found to associate with pathologic deposition of the beta-amyloid peptide (Abeta) in neuritic plaques or in the walls of cerebral vessels. We report a mutation at a novel site in APP in a three-generation Iowa family with autosomal dominant dementia beginning in the sixth or seventh decade of life. The proband and an affected brother had progressive aphasic dementia, leukoencephalopathy, and occipital calcifications. Neuropathological examination of the proband revealed severe cerebral amyloid angiopathy, widespread neurofibrillary tangles, and unusually extensive distribution of Abeta40 in plaques. The affected brothers shared a missense mutation in APP, resulting in substitution of asparagine for aspartic acid at position 694. This site corresponds to residue 23 of Abeta, thus differing from familial Alzheimer's disease mutations, which occur outside the Abeta sequence. Restriction enzyme analysis of DNA from 94 unrelated patients with sporadic cerebral amyloid angiopathy-related hemorrhage found no other instances of this mutation. These results suggest a novel site within Abeta that may promote its deposition and toxicity.
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Affiliation(s)
- T J Grabowski
- Department of Neurology and Radiology, College of Medicine, University of Iowa, Iowa City, USA
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49
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Abstract
The extracellular deposition of short amyloid peptides in the brain of patients is thought to be a central event in the pathogenesis of Alzheimer's Disease. The generation of the amyloid peptide occurs via a regulated cascade of cleavage events in its precursor protein, A beta PP. At least three enzymes are responsible for A beta PP proteolysis and have been tentatively named alpha-, beta- and gamma-secretases. The recent identification of several of these secretases is a major leap in the understanding how these secretases regulate amyloid peptide formation. Members of the ADAM family of metalloproteases are involved in the non-amyloidogenic alpha-secretase pathway. The amyloidogenic counterpart pathway is initiated by the recently cloned novel aspartate protease named BACE. The available data are conclusive and crown BACE as the long-sought beta-secretase. This enzyme is a prime candidate drug target for the development of therapy aiming to lower the amyloid burden in the disease. Finally, the gamma-secretases are intimately linked to the function of the presenilins. These multi-transmembrane domain proteins remain intriguing study objects. The hypothesis that the presenilins constitute a complete novel type of protease family, and are cleaving A beta PP within the transmembrane region, remains an issue of debate. Several questions remain unanswered and direct proof that they exert catalytic activity is still lacking. The subcellular localization of presenilins in neurons, their integration in functional multiprotein complexes and the recent identification of additional modulators of gamma-secretase, like nicastrin, indicate already that several players are involved. Nevertheless, the rapidly increasing knowledge in this area is already paving the road towards selective inhibitors of this secretase as well. It is hoped that such drugs, possibly in concert with the experimental vaccination therapies that are currently tested, will lead to a cure of this inexorable disease.
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Affiliation(s)
- D I Dominguez
- Flanders Interuniversitary Institute for Biotechnology and K.U. Leuven, Neuronal Cell Biology and Gene Transfer Laboratory, Center for Human Genetics, Gasthuisberg, B-3000 Leuven, Belgium
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50
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Papaioannou N, Tooten PC, van Ederen AM, Bohl JR, Rofina J, Tsangaris T, Gruys E. Immunohistochemical investigation of the brain of aged dogs. I. Detection of neurofibrillary tangles and of 4-hydroxynonenal protein, an oxidative damage product, in senile plaques. Amyloid 2001; 8:11-21. [PMID: 11293821 DOI: 10.3109/13506120108993810] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In the aging dog brain lesions develop spontaneously. They share some morphological characteristics with those of Alzheimer 's disease in man. Diffuse and primitive plaques are well known, whereas neuritic plaques rarely develop. Neurofibrillary tangles have not been seen in the canine. The aim of the present investigation was to study major age-related changes of the dog's brain using paraffin sections with respect to cross-immunoreactivity of tau, A beta protein and other immunoreactive components including hydroxynonenal protein, which is a marker for oxidative damage. The occurrence of neurofibrillary tangles and of the protein tau therein was studied in serial brain sections of two dogs with the Gallyas stain and by immunohistochemistry with three different antibodies against tau. Senile plaques were stained with a monoclonal anti-A beta (residues 8-17), polyclonal anti-apolipoprotein E and a monoclonal antibody against 4-hydroxynonenal (HNE). Amyloid deposits and controls were screened by Congo red staining viewed in fluorescent light, followed by polarized light for green birefringence. With the Gallyas stain and one of the antisera against tau, neurofibrillary tangles were revealed in a similar dispersed pattern, whereas the other antitau antisera gave negative results. With the anti-HNE a positive reaction was found in cerebral amyloid deposits and in vascular wall areas where amyloid deposition was confirmed by Congo-red staining, and in perivascular cells and in some neurons. These results indicate that the canine with his tangles and plaques which show oxidative changes, forms a spontaneous modelfor understanding the early changes and their interrelationships in Alzheimer's disease.
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Affiliation(s)
- N Papaioannou
- Department of Pathology, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
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