151
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Paumier JM, Py NA, García-González L, Bernard A, Stephan D, Louis L, Checler F, Khrestchatisky M, Baranger K, Rivera S. Proamyloidogenic effects of membrane type 1 matrix metalloproteinase involve MMP‐2 and BACE‐1 activities, and the modulation of APP trafficking. FASEB J 2018; 33:2910-2927. [DOI: 10.1096/fj.201801076r] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Nathalie A. Py
- Aix-Marseille UnivCNRSINPInst NeurophysiopatholMarseilleFrance
| | | | - Anne Bernard
- Aix-Marseille UnivCNRSINPInst NeurophysiopatholMarseilleFrance
| | | | - Laurence Louis
- Aix-Marseille UnivCNRSINPInst NeurophysiopatholMarseilleFrance
| | - Frédéric Checler
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC)Unité Mixte de Recherche (UMR) 7275 CNRS–Université Nice Sophia (UNS)Excellence Laboratory (Labex) Development of Innovaive Strategies for a Transdisciplinary Approach to Alzheimer's Disease (DistAlz)ValbonneFrance
| | | | - Kévin Baranger
- Aix-Marseille UnivCNRSINPInst NeurophysiopatholMarseilleFrance
| | - Santiago Rivera
- Aix-Marseille UnivCNRSINPInst NeurophysiopatholMarseilleFrance
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152
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Consequences of Pharmacological BACE Inhibition on Synaptic Structure and Function. Biol Psychiatry 2018; 84:478-487. [PMID: 29945719 DOI: 10.1016/j.biopsych.2018.04.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 04/28/2018] [Accepted: 04/28/2018] [Indexed: 12/17/2022]
Abstract
Alzheimer's disease is the most prevalent neurodegenerative disorder among elderly persons. Overt accumulation and aggregation of the amyloid-β peptide (Aβ) is thought to be the initial causative factor for Alzheimer's disease. Aβ is produced by sequential proteolytic cleavage of the amyloid precursor protein. Beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) is the initial and rate-limiting protease for the generation of Aβ. Therefore, inhibiting BACE1 is considered one of the most promising therapeutic approaches for potential treatment of Alzheimer's disease. Currently, several drugs blocking this enzyme (BACE inhibitors) are being evaluated in clinical trials. However, high-dosage BACE-inhibitor treatment interferes with structural and functional synaptic plasticity in mice. These adverse side effects may mask the therapeutic benefit of lowering the Aβ concentration. In this review, we focus on the consequences of BACE inhibition-mediated synaptic deficits and the potential clinical implications.
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153
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Focke C, Blume T, Zott B, Shi Y, Deussing M, Peters F, Schmidt C, Kleinberger G, Lindner S, Gildehaus FJ, Beyer L, von Ungern-Sternberg B, Bartenstein P, Ozmen L, Baumann K, Dorostkar MM, Haass C, Adelsberger H, Herms J, Rominger A, Brendel M. Early and Longitudinal Microglial Activation but Not Amyloid Accumulation Predicts Cognitive Outcome in PS2APP Mice. J Nucl Med 2018; 60:548-554. [DOI: 10.2967/jnumed.118.217703] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 09/10/2018] [Indexed: 02/06/2023] Open
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154
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Tseng CH. Pioglitazone Reduces Dementia Risk in Patients with Type 2 Diabetes Mellitus: A Retrospective Cohort Analysis. J Clin Med 2018; 7:E306. [PMID: 30262775 PMCID: PMC6209987 DOI: 10.3390/jcm7100306] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 09/20/2018] [Accepted: 09/23/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The beneficial effect of pioglitazone on dementia requires confirmation. METHODS The database of Taiwan's National Health Insurance was used to enroll a propensity score-matched-pair cohort of patients who had ever used pioglitazone and patients who had never used pioglitazone from Taiwanese patients with newly diagnosed diabetes mellitus during 1999⁻2008. The patients were to be alive on 1 January 2009 and were followed up for dementia until 31 December 2011. Hazard ratios were estimated using the Cox proportional hazards model. RESULTS There were 11,011 never users and 11,011 ever users of pioglitazone, with respective numbers of incident dementia of 123 and 91. The overall hazard ratio was 0.716 (95% confidence interval: 0.545⁻0.940) for ever users versus never users. The hazard ratios for the first (<11.0 months), second (11.0⁻19.6 months) and third (>19.6 months) tertiles of cumulative duration were 0.806 (0.544⁻1.193), 0.654 (0.430⁻0.994) and 0.694 (0.469⁻1.026), respectively. When cumulative duration was treated as a continuous variable, the hazard ratio was 0.987 (0.976⁻0.998). In subgroup analyses, the beneficial effect was mainly observed in patients who had not been treated with metformin. Among metformin ever users, the hazard ratio for dementia for pioglitazone ever users versus never users was 0.802 (0.580⁻1.109); and was 0.494 (0.284⁻0.857) among never users of metformin. No interaction between pioglitazone and major risk factors of dementia (i.e., stroke, hypoglycemia, head injury and Parkinson's disease) was observed. CONCLUSIONS Pioglitazone use is associated with a lower risk of dementia, especially when it is used in never users of metformin and has been used for more than 20 months.
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Affiliation(s)
- Chin-Hsiao Tseng
- Department of Internal Medicine, National Taiwan University College of Medicine, Taipei 10051, Taiwan.
- Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan 350, Taiwan.
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155
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Brendel M, Jaworska A, Overhoff F, Blume T, Probst F, Gildehaus FJ, Bartenstein P, Haass C, Bohrmann B, Herms J, Willem M, Rominger A. Efficacy of chronic BACE1 inhibition in PS2APP mice depends on the regional Aβ deposition rate and plaque burden at treatment initiation. Theranostics 2018; 8:4957-4968. [PMID: 30429879 PMCID: PMC6217065 DOI: 10.7150/thno.27868] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 08/14/2018] [Indexed: 12/31/2022] Open
Abstract
Beta secretase (BACE) inhibitors are promising therapeutic compounds currently in clinical phase II/III trials. Preclinical [18F]-florbetaben (FBB) amyloid PET imaging facilitates longitudinal monitoring of amyloidosis in Alzheimer's disease (AD) mouse models. Therefore, we applied this theranostic concept to investigate, by serial FBB PET, the efficacy of a novel BACE1 inhibitor in the PS2APP mouse, which is characterized by early and massive amyloid deposition. Methods: PS2APP and C57BL/6 (WT) mice were assigned to treatment (PS2APP: N=13; WT: N=11) and vehicle control (PS2APP: N=13; WT: N=11) groups at the age of 9.5 months. All animals had a baseline PET scan and follow-up scans at two months and after completion of the four-month treatment period. In addition to this longitudinal analysis of cerebral amyloidosis by PET, we undertook biochemical amyloid peptide quantification and histological amyloid plaque analyses after the final PET session. Results: BACE1 inhibitor-treated transgenic mice revealed a progression of the frontal cortical amyloid signal by 8.4 ± 2.2% during the whole treatment period, which was distinctly lower when compared to vehicle-treated mice (15.3 ± 4.4%, p<0.001). A full inhibition of progression was evident in regions with <3.7% of the increase in controls, whereas regions with >10% of the increase in controls showed only 40% attenuation with BACE1 inhibition. BACE1 inhibition in mice with lower amyloidosis at treatment initiation showed a higher efficacy in attenuating progression to PET. A predominant reduction of small plaques in treated mice indicated a main effect of BACE1 on inhibition of de novo amyloidogenesis. Conclusions: This theranostic study with BACE1 treatment in a transgenic AD model together with amyloid PET monitoring indicated that progression of amyloidosis is more effectively reduced in regions with low initial plaque development and revealed the need of an early treatment initiation during amyloidogenesis.
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Affiliation(s)
- Matthias Brendel
- Department of Nuclear Medicine, University Hospital, LMU Munich; Munich, Germany
| | - Anna Jaworska
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Felix Overhoff
- Department of Nuclear Medicine, University Hospital, LMU Munich; Munich, Germany
| | - Tanja Blume
- Department of Nuclear Medicine, University Hospital, LMU Munich; Munich, Germany
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
| | - Federico Probst
- Department of Nuclear Medicine, University Hospital, LMU Munich; Munich, Germany
| | | | - Peter Bartenstein
- Department of Nuclear Medicine, University Hospital, LMU Munich; Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Christian Haass
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
- Biomedical Center (BMC), Ludwig-Maximilians-University Munich, 81377 Munich, Germany
| | | | - Jochen Herms
- DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Michael Willem
- Biomedical Center (BMC), Ludwig-Maximilians-University Munich, 81377 Munich, Germany
| | - Axel Rominger
- Department of Nuclear Medicine, University Hospital, LMU Munich; Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
- Department of Nuclear Medicine, Inselspital, University Hospital Bern, Bern, Switzerland
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156
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Paschkowsky S, Recinto SJ, Young JC, Bondar AN, Munter LM. Membrane cholesterol as regulator of human rhomboid protease RHBDL4. J Biol Chem 2018; 293:15556-15568. [PMID: 30143535 DOI: 10.1074/jbc.ra118.002640] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 08/18/2018] [Indexed: 12/28/2022] Open
Abstract
In the last decade, intramembrane proteases have gained increasing attention because of their many links to various diseases. Nevertheless, our understanding as to how they function or how they are regulated is still limited, especially when it comes to human homologues. In this regard, here we sought to unravel mechanisms of regulation of the protease rhomboid-like protein-4 (RHBDL4), one of five active human serine intramembrane proteases. In view of our recent finding that human RHBDL4 efficiently cleaves the amyloid precursor protein (APP), a key protein in the pathology of Alzheimer's disease, we used established reagents to modulate the cellular cholesterol content and analyzed the effects of this modulation on RHBDL4-mediated processing of endogenous APP. We discovered that lowering membrane cholesterol levels increased the levels of RHBDL4-specific endogenous APP fragments, whereas high cholesterol levels had the opposite effect. Direct binding of cholesterol to APP did not mediate these modulating effects of cholesterol. Instead, using homology modeling, we identified two potential cholesterol-binding motifs in the transmembrane helices 3 and 6 of RHBDL4. Substitution of the essential tyrosine residues of the potential cholesterol-binding motifs to alanine increased the levels of endogenous APP C-terminal fragments, reflecting enhanced RHBDL4 activity. In summary, we provide evidence that the activity of RHBDL4 is regulated by cholesterol likely through a direct binding of cholesterol to the enzyme.
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Affiliation(s)
- Sandra Paschkowsky
- From the Department of Pharmacology and Therapeutics and Cell Information Systems Group and
| | | | - Jason C Young
- Department of Biochemistry and Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec H3G 0B1, Canada and
| | - Ana-Nicoleta Bondar
- the Department of Physics, Theoretical Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany
| | - Lisa Marie Munter
- From the Department of Pharmacology and Therapeutics and Cell Information Systems Group and
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157
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Dunys J, Valverde A, Checler F. Are N- and C-terminally truncated Aβ species key pathological triggers in Alzheimer's disease? J Biol Chem 2018; 293:15419-15428. [PMID: 30143530 DOI: 10.1074/jbc.r118.003999] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The histopathology of Alzheimer's disease (AD) is characterized by neuronal loss, neurofibrillary tangles, and senile plaque formation. The latter results from an exacerbated production (familial AD cases) or altered degradation (sporadic cases) of 40/42-amino acid-long β-amyloid peptides (Aβ peptides) that are produced by sequential cleavages of Aβ precursor protein (βAPP) by β- and γ-secretases. The amyloid cascade hypothesis proposes a key role for the full-length Aβ42 and the Aβ40/42 ratio in AD etiology, in which soluble Aβ oligomers lead to neurotoxicity, tau hyperphosphorylation, aggregation, and, ultimately, cognitive defects. However, following this postulate, during the last decade, several clinical approaches aimed at decreasing full-length Aβ42 production or neutralizing it by immunotherapy have failed to reduce or even stabilize AD-related decline. Thus, the Aβ peptide (Aβ40/42)-centric hypothesis is probably a simplified view of a much more complex situation involving a multiplicity of APP fragments and Aβ catabolites. Indeed, biochemical analyses of AD brain deposits and fluids have unraveled an Aβ peptidome consisting of additional Aβ-related species. Such Aβ catabolites could be due to either primary enzymatic cleavages of βAPP or secondary processing of Aβ itself by exopeptidases. Here, we review the diversity of N- and C-terminally truncated Aβ peptides and their biosynthesis and outline their potential function/toxicity. We also highlight their potential as new pharmaceutical targets and biomarkers.
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Affiliation(s)
- Julie Dunys
- From the Université Côte d'Azur, INSERM, CNRS, IPMC, Team labeled "Laboratory of Excellence (LABEX) Distalz," 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France
| | - Audrey Valverde
- From the Université Côte d'Azur, INSERM, CNRS, IPMC, Team labeled "Laboratory of Excellence (LABEX) Distalz," 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France
| | - Frédéric Checler
- From the Université Côte d'Azur, INSERM, CNRS, IPMC, Team labeled "Laboratory of Excellence (LABEX) Distalz," 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France
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158
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Novel Quantitative Analyses of Spontaneous Synaptic Events in Cortical Pyramidal Cells Reveal Subtle Parvalbumin-Expressing Interneuron Dysfunction in a Knock-In Mouse Model of Alzheimer's Disease. eNeuro 2018; 5:eN-CFN-0059-18. [PMID: 30105300 PMCID: PMC6088364 DOI: 10.1523/eneuro.0059-18.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/19/2018] [Accepted: 06/24/2018] [Indexed: 12/19/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder that has become a compelling global public health concern. Besides pathological hallmarks such as extracellular amyloid plaques, intracellular neurofibrillary tangles (NFTs), and loss of neurons and synapses, clinical reports have shown that epileptiform activity, even seizures, can occur early in the disease. Aberrant synaptic and network activities as well as epileptiform discharges have also been observed in various mouse models of AD. The new AppNL-F mouse model is generated by a gene knock-in approach and there are limited studies on basic synaptic properties in AppNL-F mice. Therefore, we applied quantitative methods to analyze spontaneous excitatory and inhibitory synaptic events in parietal cortex layer 2/3 pyramidal cells. First, by an objective amplitude distribution analysis, we found decreased amplitudes of spontaneous IPSCs (sIPSCs) in aged AppNL-F mice caused by a reduction in the amplitudes of the large sIPSCs with fast rates of rise, consistent with deficits in the function of parvalbumin-expressing interneurons (PV INs). Second, we calculated the burstiness and memory in a series of successive synaptic events. Lastly, by using a novel approach to determine the excitation-to-inhibition (E/I) ratio, we found no changes in the AppNL-F mice, indicating that homeostatic mechanisms may have maintained the overall balance of excitation and inhibition in spite of a mildly impaired PV IN function.
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159
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Lichtenthaler SF, Lemberg MK, Fluhrer R. Proteolytic ectodomain shedding of membrane proteins in mammals-hardware, concepts, and recent developments. EMBO J 2018; 37:e99456. [PMID: 29976761 PMCID: PMC6068445 DOI: 10.15252/embj.201899456] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/05/2018] [Accepted: 06/18/2018] [Indexed: 12/14/2022] Open
Abstract
Proteolytic removal of membrane protein ectodomains (ectodomain shedding) is a post-translational modification that controls levels and function of hundreds of membrane proteins. The contributing proteases, referred to as sheddases, act as important molecular switches in processes ranging from signaling to cell adhesion. When deregulated, ectodomain shedding is linked to pathologies such as inflammation and Alzheimer's disease. While proteases of the "a disintegrin and metalloprotease" (ADAM) and "beta-site APP cleaving enzyme" (BACE) families are widely considered as sheddases, in recent years a much broader range of proteases, including intramembrane and soluble proteases, were shown to catalyze similar cleavage reactions. This review demonstrates that shedding is a fundamental process in cell biology and discusses the current understanding of sheddases and their substrates, molecular mechanisms and cellular localizations, as well as physiological functions of protein ectodomain shedding. Moreover, we provide an operational definition of shedding and highlight recent conceptual advances in the field. While new developments in proteomics facilitate substrate discovery, we expect that shedding is not a rare exception, but rather the rule for many membrane proteins, and that many more interesting shedding functions await discovery.
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Affiliation(s)
- Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, Klinikum rechts der Isar, School of Medicine, and Institute for Advanced Study, Technical University Munich, Munich, Germany
- Munich Center for Systems Neurology (SyNergy), Munich, Germany
| | - Marius K Lemberg
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Regina Fluhrer
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Biomedizinisches Centrum (BMC), Ludwig-Maximilians University of Munich, Munich, Germany
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160
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Lanza V, Bellia F, Rizzarelli E. An inorganic overview of natural Aβ fragments: Copper(II) and zinc(II)-mediated pathways. Coord Chem Rev 2018. [DOI: 10.1016/j.ccr.2018.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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161
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Ashton NJ, Schöll M, Heurling K, Gkanatsiou E, Portelius E, Höglund K, Brinkmalm G, Hye A, Blennow K, Zetterberg H. Update on biomarkers for amyloid pathology in Alzheimer's disease. Biomark Med 2018; 12:799-812. [DOI: 10.2217/bmm-2017-0433] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
At the center of Alzheimer's disease pathogenesis is the aberrant aggregation of amyloid-β (Aβ) into oligomers, fibrils and plaques. Effective monitoring of Aβ deposition directly in patients is essential to assist anti-Aβ therapeutics in target engagement and participant selection. In the advent of approved anti-Aβ therapeutics, biomarkers will become of fundamental importance in initiating treatments having disease modifying effects at the earliest stage. Two well-established Aβ biomarkers are widely utilized: Aβ-binding ligands for positron emission tomography and immunoassays to measure Aβ42 in cerebrospinal fluid. In this review, we will discuss the current clinical, diagnostic and research state of biomarkers for Aβ pathology. Furthermore, we will explore the current application of blood-based markers to assess Aβ pathology.
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Affiliation(s)
- Nicholas J Ashton
- King's College London, Institute of Psychiatry, Psychology & Neuroscience, Maurice Wohl Clinical Neuroscience Institute, London, UK
- NIHR Biomedical Research Centre for Mental Health & Biomedical Research Unit for Dementia at South London & Maudsley NHS Foundation, London, UK
- Wallenberg Centre for Molecular & Translational Medicine, University of Gothenburg, Gothenburg, Sweden
- Department of Psychiatry & Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Michael Schöll
- Wallenberg Centre for Molecular & Translational Medicine, University of Gothenburg, Gothenburg, Sweden
- Clinical Memory Research Unit, Department of Clinical Sciences, Malmö, Lund University, Lund, Sweden
| | - Kerstin Heurling
- Wallenberg Centre for Molecular & Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Eleni Gkanatsiou
- Department of Psychiatry & Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Erik Portelius
- Department of Psychiatry & Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Kina Höglund
- Department of Psychiatry & Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Gunnar Brinkmalm
- Department of Psychiatry & Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Abdul Hye
- King's College London, Institute of Psychiatry, Psychology & Neuroscience, Maurice Wohl Clinical Neuroscience Institute, London, UK
- NIHR Biomedical Research Centre for Mental Health & Biomedical Research Unit for Dementia at South London & Maudsley NHS Foundation, London, UK
| | - Kaj Blennow
- Department of Psychiatry & Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry & Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
- UK Dementia Research Institute at UCL, London, UK
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162
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Hong W, Wang Z, Liu W, O'Malley TT, Jin M, Willem M, Haass C, Frosch MP, Walsh DM. Diffusible, highly bioactive oligomers represent a critical minority of soluble Aβ in Alzheimer's disease brain. Acta Neuropathol 2018; 136:19-40. [PMID: 29687257 PMCID: PMC6647843 DOI: 10.1007/s00401-018-1846-7] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 04/02/2018] [Indexed: 01/02/2023]
Abstract
Significant data suggest that soluble Aβ oligomers play an important role in Alzheimer's disease (AD), but there is great confusion over what exactly constitutes an Aβ oligomer and which oligomers are toxic. Most studies have utilized synthetic Aβ peptides, but the relevance of these test tube experiments to the conditions that prevail in AD is uncertain. A few groups have studied Aβ extracted from human brain, but they employed vigorous tissue homogenization which is likely to release insoluble Aβ that was sequestered in plaques during life. Several studies have found such extracts to possess disease-relevant activity and considerable efforts are being made to purify and better understand the forms of Aβ therein. Here, we compared the abundance of Aβ in AD extracts prepared by traditional homogenization versus using a far gentler extraction, and assessed their bioactivity via real-time imaging of iPSC-derived human neurons plus the sensitive functional assay of long-term potentiation. Surprisingly, the amount of Aβ retrieved by gentle extraction constituted only a small portion of that released by traditional homogenization, but this readily diffusible fraction retained all of the Aβ-dependent neurotoxic activity. Thus, the bulk of Aβ extractable from AD brain was innocuous, and only the small portion that was aqueously diffusible caused toxicity. This unexpected finding predicts that generic anti-oligomer therapies, including Aβ antibodies now in trials, may be bound up by the large pool of inactive oligomers, whereas agents that specifically target the small pool of diffusible, bioactive Aβ would be more useful. Furthermore, our results indicate that efforts to purify and target toxic Aβ must employ assays of disease-relevant activity. The approaches described here should enable these efforts, and may assist the study of other disease-associated aggregation-prone proteins.
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Affiliation(s)
- Wei Hong
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Zemin Wang
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Wen Liu
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Tiernan T O'Malley
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Ming Jin
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA
| | - Michael Willem
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, 81377, Munich, Germany
| | - Christian Haass
- Biomedical Center (BMC), Biochemistry, Ludwig-Maximilians-University Munich, 81377, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), 81377, Munich, Germany
- German Center for Neurodegenerative Diseases (DZNE) Munich, 81377, Munich, Germany
| | - Matthew P Frosch
- Massachusetts General Institute for Neurodegenerative Disease, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, 02129, USA
| | - Dominic M Walsh
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Building for Transformative Medicine, 60 Fenwood Road, Boston, MA, 02115, USA.
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163
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Donner L, Gremer L, Ziehm T, Gertzen CGW, Gohlke H, Willbold D, Elvers M. Relevance of N-terminal residues for amyloid-β binding to platelet integrin α IIbβ 3, integrin outside-in signaling and amyloid-β fibril formation. Cell Signal 2018; 50:121-130. [PMID: 29964150 DOI: 10.1016/j.cellsig.2018.06.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 11/26/2022]
Abstract
A pathological hallmark of Alzheimer's disease (AD) is the aggregation of amyloid-β peptides (Aβ) into fibrils, leading to deposits in cerebral parenchyma and vessels known as cerebral amyloid angiopathy (CAA). Platelets are major players of hemostasis but are also implicated in AD. Recently we provided strong evidence for a direct contribution of platelets to AD pathology. We found that monomeric Aβ40 binds through its RHDS sequence to integrin αIIbβ3, and promotes the formation of fibrillar Aβ aggregates by the secretion of adenosine diphosphate (ADP) and the chaperone protein clusterin (CLU) from platelets. Here we investigated the molecular mechanisms of Aβ binding to integrin αIIbβ3 by using Aβ11 and Aβ16 peptides. These peptides include the RHDS binding motif important for integrin binding but lack the central hydrophobic core and the C-terminal sequence of Aβ. We observed platelet adhesion to truncated N-terminal Aβ11 and Aβ16 peptides that was not mediated by integrin αIIbβ3. Thus, no integrin outside-in signaling and reduced CLU release was detected. Accordingly, platelet mediated Aβ fibril formation was not observed. Taken together, the RHDS motif of Aβ is not sufficient for Aβ binding to platelet integrin αIIbβ3 and platelet mediated Aβ fibril formation but requires other recognition or binding motifs important for platelet mediated processes in CAA. Thus, increased understanding of the molecular mechanisms of Aβ binding to platelet integrin αIIbβ3 is important to understand the role of platelets in amyloid pathology.
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Affiliation(s)
- Lili Donner
- Department of Vascular and Endovascular Surgery, Heinrich-Heine-University University Medical Center, Moorenstraße.5, 40225 Düsseldorf, Germany
| | - Lothar Gremer
- Institute of Physical Biology, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany; Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany
| | - Tamar Ziehm
- Institute of Physical Biology, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany; Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany
| | - Christoph G W Gertzen
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Holger Gohlke
- Institute for Pharmaceutical and Medicinal Chemistry, Department of Mathematics and Natural Sciences, Heinrich-Heine-University, Düsseldorf, Germany; John von Neumann Institute for Computing (NIC), Jülich Supercomputing Centre (JSC), Institute for Complex Systems - Structural Biochemistry (ICS-6) Research Centre Jülich, 52425 Jülich, Germany
| | - Dieter Willbold
- Institute of Physical Biology, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany; Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany
| | - Margitta Elvers
- Department of Vascular and Endovascular Surgery, Heinrich-Heine-University University Medical Center, Moorenstraße.5, 40225 Düsseldorf, Germany.
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164
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Abstract
Alzheimer’s disease is one of the most severe neurodegenerative diseases among elderly people.
Different pathogenic factors for Alzheimer’s disease have been posited and
studied in recent decades, but no effective treatment has been found,
necessitating further studies. In this Viewpoint article, we assess studies on
the mechanisms underlying the accumulation of amyloid (Aβ) peptide and the
formation of Aβ oligomers because their accumulation in amyloid plaques in
brain tissue has become a well-studied hallmark of Alzheimer’s disease. We focus
on the production of Aβ and its impact on the function of synapses and
neural circuits, and also discuss the clinical prospects for amyloid-targeted
therapies.
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Affiliation(s)
- Yixiu Zhou
- Medical College of Soochow University, Soochow University, Suzhou, Jiangsu 215004, China
| | - Yuhui Sun
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215123, China
| | - Quan-Hong Ma
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215123, China
| | - Yaobo Liu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu 215123, China
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165
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Sharma B, Ranganathan SV, Belfort G. Weaker N-Terminal Interactions for the Protective over the Causative Aβ Peptide Dimer Mutants. ACS Chem Neurosci 2018; 9:1247-1253. [PMID: 29465978 DOI: 10.1021/acschemneuro.7b00412] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Knowing that abeta amyloid peptide (Aβ42) dimers are the smallest and most abundant neurotoxic oligomers for Alzheimer's disease (AD), we used molecular simulations with advanced sampling methods (replica-exchange) to characterize and compare interactions between the N-termini (residues 1-16) of wild type (WT-WT) and five mutant dimers under constrained and unconstrained conditions. The number of contacts and distances between the N-termini, and contact maps of their conformational landscape illustrate substantial differences for a single residue change. The N-terminal contacts are significantly diminished for the dimers containing the monomers that protect against (WT-A2T) as compared with those that predispose toward (A2V-A2V) AD and for the control WT-WT dimers. The reduced number of N-terminal contacts not only occurs at or near the second residue mutations but also is distributed through to the 10th residue. These findings provide added support to the accumulating evidence for the "N-terminal hypothesis of AD" and offer an alternate mechanism for the cause of protection from the A2T mutant.
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Affiliation(s)
- Bhanushee Sharma
- Howard P Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, United States
| | - Srivathsan V. Ranganathan
- The RNA Institute, University at Albany, State University of New York, Albany, New York 12222, United States
| | - Georges Belfort
- Howard P Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, United States
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166
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Zhang D, Mably AJ, Walsh DM, Rowan MJ. Peripheral Interventions Enhancing Brain Glutamate Homeostasis Relieve Amyloid β- and TNFα- Mediated Synaptic Plasticity Disruption in the Rat Hippocampus. Cereb Cortex 2018; 27:3724-3735. [PMID: 27390019 DOI: 10.1093/cercor/bhw193] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Dysregulation of glutamate homeostasis in the interstitial fluid of the brain is strongly implicated in causing synaptic dysfunction in many neurological and psychiatric illnesses. In the case of Alzheimer's disease (AD), amyloid β (Aβ)-mediated disruption of synaptic plasticity and memory can be alleviated by interventions that directly remove glutamate or block certain glutamate receptors. An alternative strategy is to facilitate the removal of excess glutamate from the nervous system by activating peripheral glutamate clearance systems. One such blood-based system, glutamate oxaloacetate transaminase (GOT), is activated by oxaloacetate, which acts as a co-substrate. We report here that synthetic and AD brain-derived Aβ-mediated inhibition of synaptic long-term potentiation in the hippocampus is alleviated by oxaloacetate. Moreover the effect of oxaloacetate was GOT-dependent. The disruptive effects of a general inhibitor of excitatory amino acid transport or TNFα, a pro-inflammatory mediator of Aβ action, were also reversed by oxaloacetate. Furthermore, another intervention that increases peripheral glutamate clearance, peritoneal dialysis, mimicked the beneficial effect of oxaloacetate. These findings lend support to the promotion of the peripheral clearance of glutamate as a means to alleviate synaptic dysfunction that is caused by impaired glutamate homeostasis in the brain.
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Affiliation(s)
- Dainan Zhang
- Department of Pharmacology and Therapeutics, and Trinity College Institute of Neuroscience, Trinity College, Dublin 2, Ireland
| | - Alexandra J Mably
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham & Women's Hospital, Harvard Institute of Medicine, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Dominic M Walsh
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham & Women's Hospital, Harvard Institute of Medicine, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Michael J Rowan
- Department of Pharmacology and Therapeutics, and Trinity College Institute of Neuroscience, Trinity College, Dublin 2, Ireland
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167
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Endosomal-Lysosomal Cholesterol Sequestration by U18666A Differentially Regulates Amyloid Precursor Protein (APP) Metabolism in Normal and APP-Overexpressing Cells. Mol Cell Biol 2018. [PMID: 29530923 DOI: 10.1128/mcb.00529-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Amyloid β (Aβ) peptide, derived from amyloid precursor protein (APP), plays a critical role in the development of Alzheimer's disease. Current evidence indicates that altered levels or subcellular distribution of cholesterol can regulate Aβ production and clearance, but it remains unclear how cholesterol sequestration within the endosomal-lysosomal (EL) system can influence APP metabolism. Thus, we evaluated the effects of U18666A, which triggers cholesterol redistribution within the EL system, on mouse N2a cells expressing different levels of APP in the presence or absence of extracellular cholesterol and lipids provided by fetal bovine serum (FBS). Our results reveal that U18666A and FBS differentially increase the levels of APP and its cleaved products, the α-, β-, and η-C-terminal fragments, in N2a cells expressing normal levels of mouse APP (N2awt), higher levels of human wild-type APP (APPwt), or "Swedish" mutant APP (APPsw). The cellular levels of Aβ1-40/Aβ1-42 were markedly increased in U18666A-treated APPwt and APPsw cells. Our studies further demonstrate that APP and its cleaved products are partly accumulated in the lysosomes, possibly due to decreased clearance. Finally, we show that autophagy inhibition plays a role in mediating U18666A effects. Collectively, these results suggest that altered levels and distribution of cholesterol and lipids can differentially regulate APP metabolism depending on the nature of APP expression.
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168
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A simplified protocol for differentiation of electrophysiologically mature neuronal networks from human induced pluripotent stem cells. Mol Psychiatry 2018; 23:1336-1344. [PMID: 28416807 PMCID: PMC5984104 DOI: 10.1038/mp.2017.56] [Citation(s) in RCA: 137] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 12/24/2016] [Accepted: 02/10/2017] [Indexed: 02/07/2023]
Abstract
Progress in elucidating the molecular and cellular pathophysiology of neuropsychiatric disorders has been hindered by the limited availability of living human brain tissue. The emergence of induced pluripotent stem cells (iPSCs) has offered a unique alternative strategy using patient-derived functional neuronal networks. However, methods for reliably generating iPSC-derived neurons with mature electrophysiological characteristics have been difficult to develop. Here, we report a simplified differentiation protocol that yields electrophysiologically mature iPSC-derived cortical lineage neuronal networks without the need for astrocyte co-culture or specialized media. This protocol generates a consistent 60:40 ratio of neurons and astrocytes that arise from a common forebrain neural progenitor. Whole-cell patch-clamp recordings of 114 neurons derived from three independent iPSC lines confirmed their electrophysiological maturity, including resting membrane potential (-58.2±1.0 mV), capacitance (49.1±2.9 pF), action potential (AP) threshold (-50.9±0.5 mV) and AP amplitude (66.5±1.3 mV). Nearly 100% of neurons were capable of firing APs, of which 79% had sustained trains of mature APs with minimal accommodation (peak AP frequency: 11.9±0.5 Hz) and 74% exhibited spontaneous synaptic activity (amplitude, 16.03±0.82 pA; frequency, 1.09±0.17 Hz). We expect this protocol to be of broad applicability for implementing iPSC-based neuronal network models of neuropsychiatric disorders.
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169
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Fisher DW, Bennett DA, Dong H. Sexual dimorphism in predisposition to Alzheimer's disease. Neurobiol Aging 2018; 70:308-324. [PMID: 29754747 DOI: 10.1016/j.neurobiolaging.2018.04.004] [Citation(s) in RCA: 144] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 04/08/2018] [Accepted: 04/10/2018] [Indexed: 12/20/2022]
Abstract
Clinical studies indicate that Alzheimer's disease (AD) disproportionately affects women in both disease prevalence and rate of symptom progression, but the mechanisms underlying this sexual divergence are unknown. Although some have suggested this difference in risk is a reflection of the known differences in longevity between men and women, mounting clinical and preclinical evidence supports women also having intrinsic susceptibilities toward the disease. Although a number of potential risk factors have been hypothesized to mediate these differences, none have been definitively verified. In this review, we first summarize the epidemiologic studies of prevalence and incidence of AD among the sexes. Next, we discuss the most likely risk factors to date that interact with biological sex, including (1) genetic factors, (2) sex hormones (3) deviations in brain structure, (4) inflammation and microglia, and (5) and psychosocial stress responses. Overall, though differences in life span are likely to account for part of the divide between the sexes in AD prevalence, the abundance of preclinical and clinical evidence presented here suggests an increase in intrinsic AD risk for women. Therefore, future studies focusing on the underlying biological mechanisms for this phenomenon are needed to better understand AD pathogenesis in both sexes, with the eventual goal of sex-specific prevention and treatment strategies.
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Affiliation(s)
- Daniel W Fisher
- Departments of Psychiatry and Behavioral Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - David A Bennett
- Department of Neurological Sciences, Rush Alzheimer's Disease Center, Rush Medical College, Chicago, IL, USA
| | - Hongxin Dong
- Departments of Psychiatry and Behavioral Sciences, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.
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170
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Galzitskaya OV, Galushko EI, Selivanova OM. Studies of the Process of Amyloid Formation by Aβ Peptide. BIOCHEMISTRY (MOSCOW) 2018; 83:S62-S80. [PMID: 29544432 DOI: 10.1134/s0006297918140079] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Studies of the process of amyloid formation by Aβ peptide have been topical due to the critical role of this peptide in the pathogenesis of Alzheimer's disease. Many articles devoted to this process are available in the literature; however, none of them gives a detailed description of the mechanism of the process of generation of amyloids. Moreover, there are no reliable data on the influence of modified forms of Aβ peptide on its amyloid formation. To appreciate the role of Aβ aggregation in the pathogenesis of Alzheimer's disease and to develop a strategy for its treatment, it is necessary to have a well-defined description of the molecular mechanism underlying the formation of amyloids as well as the contribution of each intermediate to this process. We are convinced that a combined analysis of theoretical and experimental methods is a way for understanding molecular mechanisms of numerous diseases. Based on our experimental data and molecular modeling, we have constructed a general model of the process of amyloid formation by Aβ peptide. Using the data described in our previous publications, we propose a model of amyloid formation by this peptide that differs from the generally accepted model. Our model can be applied to other proteins and peptides as well. According to this model, the main building unit for the formation of amyloid fibrils is a ring-like oligomer. Upon interaction with each other, ring-like oligomers form long fibrils of different morphology. This mechanism of generation of amyloid fibrils may be common for other proteins and peptides.
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Affiliation(s)
- O V Galzitskaya
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
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171
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Johansson P, Kaspersson K, Gurrell IK, Bäck E, Eketjäll S, Scott CW, Cebers G, Thorne P, McKenzie MJ, Beaton H, Davey P, Kolmodin K, Holenz J, Duggan ME, Budd Haeberlein S, Bürli RW. Toward β-Secretase-1 Inhibitors with Improved Isoform Selectivity. J Med Chem 2018; 61:3491-3502. [DOI: 10.1021/acs.jmedchem.7b01716] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Patrik Johansson
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, S-43183 Mölndal, Sweden
| | - Karin Kaspersson
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, S-43183 Mölndal, Sweden
| | - Ian K. Gurrell
- Neuroscience, IMED Biotech Unit, AstraZeneca, Cambridge CB21 6GH, U.K
| | - Elisabeth Bäck
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, S-43183 Mölndal, Sweden
| | - Susanna Eketjäll
- Cardiovascular and Metabolic Diseases, IMED Biotech Unit, AstraZeneca, 141 57 Huddinge, Sweden
| | - Clay W. Scott
- Discovery Safety, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Waltham, Massachusetts 02451, United States
| | - Gvido Cebers
- Neuroscience, IMED Biotech Unit, AstraZeneca, Cambridge CB21 6GH, U.K
| | | | | | | | - Paul Davey
- Oncology Chemistry, IMED Biotech Unit, AstraZeneca, Cambridge CB4 0WG, U.K
| | | | - Jörg Holenz
- Neuroscience, IMED Biotech Unit, AstraZeneca, Cambridge CB21 6GH, U.K
| | - Mark E. Duggan
- Neuroscience, IMED Biotech Unit, AstraZeneca, Cambridge CB21 6GH, U.K
| | | | - Roland W. Bürli
- Neuroscience, IMED Biotech Unit, AstraZeneca, Cambridge CB21 6GH, U.K
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172
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Cheignon C, Tomas M, Bonnefont-Rousselot D, Faller P, Hureau C, Collin F. Oxidative stress and the amyloid beta peptide in Alzheimer's disease. Redox Biol 2018; 14:450-464. [PMID: 29080524 PMCID: PMC5680523 DOI: 10.1016/j.redox.2017.10.014] [Citation(s) in RCA: 1297] [Impact Index Per Article: 216.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 10/14/2017] [Accepted: 10/17/2017] [Indexed: 01/12/2023] Open
Abstract
Oxidative stress is known to play an important role in the pathogenesis of a number of diseases. In particular, it is linked to the etiology of Alzheimer's disease (AD), an age-related neurodegenerative disease and the most common cause of dementia in the elderly. Histopathological hallmarks of AD are intracellular neurofibrillary tangles and extracellular formation of senile plaques composed of the amyloid-beta peptide (Aβ) in aggregated form along with metal-ions such as copper, iron or zinc. Redox active metal ions, as for example copper, can catalyze the production of Reactive Oxygen Species (ROS) when bound to the amyloid-β (Aβ). The ROS thus produced, in particular the hydroxyl radical which is the most reactive one, may contribute to oxidative damage on both the Aβ peptide itself and on surrounding molecule (proteins, lipids, …). This review highlights the existing link between oxidative stress and AD, and the consequences towards the Aβ peptide and surrounding molecules in terms of oxidative damage. In addition, the implication of metal ions in AD, their interaction with the Aβ peptide and redox properties leading to ROS production are discussed, along with both in vitro and in vivo oxidation of the Aβ peptide, at the molecular level.
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Affiliation(s)
- C Cheignon
- LCC (Laboratoire de Chimie de Coordination), CNRS UPR 8241, 205 route de Narbonne, 31062 Toulouse Cedex 09, France; Université de Toulouse; UPS, INPT, 31077 Toulouse, France
| | - M Tomas
- LCC (Laboratoire de Chimie de Coordination), CNRS UPR 8241, 205 route de Narbonne, 31062 Toulouse Cedex 09, France; Université de Toulouse; UPS, INPT, 31077 Toulouse, France
| | - D Bonnefont-Rousselot
- Department of Metabolic Biochemistry, La Pitié Salpêtrière-Charles Foix University Hospital (AP-HP), Paris, France; Department of Biochemistry, Faculty of Pharmacy, Paris Descartes University, Paris, France; CNRS UMR8258 - INSERM U1022, Faculty of Pharmacy, Paris Descartes University, Paris, France
| | - P Faller
- Biometals and Biology Chemistry, Institut de Chimie (CNRS UMR 7177), University of Strasbourg, 4 rue B. Pascal, 67081 Strasbourg Cedex, France
| | - C Hureau
- LCC (Laboratoire de Chimie de Coordination), CNRS UPR 8241, 205 route de Narbonne, 31062 Toulouse Cedex 09, France; Université de Toulouse; UPS, INPT, 31077 Toulouse, France
| | - F Collin
- LCC (Laboratoire de Chimie de Coordination), CNRS UPR 8241, 205 route de Narbonne, 31062 Toulouse Cedex 09, France; Université de Toulouse; UPS, INPT, 31077 Toulouse, France.
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173
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Abstract
Alzheimer's disease (AD), the main form of dementia in the elderly, is the most common progressive neurodegenerative disease characterized by rapidly progressive cognitive dysfunction and behavior impairment. AD exhibits a considerable heritability and great advances have been made in approaches to searching the genetic etiology of AD. In AD genetic studies, methods have developed from classic linkage-based and candidate-gene-based association studies to genome-wide association studies (GWAS) and next generation sequencing (NGS). The identification of new susceptibility genes has provided deeper insights to understand the mechanisms underlying AD. In addition to searching novel genes associated with AD in large samples, the NGS technologies can also be used to shed light on the 'black matter' discovery even in smaller samples. The shift in AD genetics between traditional studies and individual sequencing will allow biomaterials of each patient as the central unit of genetic studies. This review will cover genetic findings in AD and consequences of AD genetic findings. Firstly, we will discuss the discovery of mutations in APP, PSEN1, PSEN2, APOE, and ADAM10. Then we will summarize and evaluate the information obtained from GWAS of AD. Finally, we will outline the efforts to identify rare variants associated with AD using NGS.
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174
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van Maanen EMT, van Steeg TJ, Ahsman MJ, Michener MS, Savage MJ, Kennedy ME, Kleijn HJ, Stone J, Danhof M. Extending a Systems Model of the APP Pathway: Separation of β- and γ-Secretase Sequential Cleavage Steps of APP. J Pharmacol Exp Ther 2018; 365:507-518. [PMID: 29563326 DOI: 10.1124/jpet.117.244699] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 02/05/2018] [Indexed: 11/22/2022] Open
Abstract
The abnormal accumulation of amyloid-β (Aβ) in the brain parenchyma has been posited as a central event in the pathophysiology of Alzheimer's disease. Recently, we have proposed a systems pharmacology model of the amyloid precursor protein (APP) pathway, describing the Aβ APP metabolite responses (Aβ40, Aβ42, sAPPα, and sAPPβ) to β-secretase 1 (BACE1) inhibition. In this investigation this model was challenged to describe Aβ dynamics following γ-secretase (GS) inhibition. This led an extended systems pharmacology model, with separate descriptions to characterize the sequential cleavage steps of APP by BACE1 and GS, to describe the differences in Aβ response to their respective inhibition. Following GS inhibition, a lower Aβ40 formation rate constant was observed, compared with BACE1 inhibition. Both BACE1 and GS inhibition were predicted to lower Aβ oligomer levels. Further model refinement and new data may be helpful to fully understand the difference in Aβ dynamics following BACE1 versus GS inhibition.
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Affiliation(s)
- Eline M T van Maanen
- Division of Pharmacology, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands (E.M.T.v.M., M.D.); Leiden Experts on Advanced Pharmacokinetics and Pharmacodynamics, Leiden, The Netherlands (E.M.T.v.M., T.J.v.S., M.J.A.); and Merck & Company, Inc., Kenilworth, New Jersey (M.S.M., M.J.S., M.E.K., H.J.K., J.S.)
| | - Tamara J van Steeg
- Division of Pharmacology, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands (E.M.T.v.M., M.D.); Leiden Experts on Advanced Pharmacokinetics and Pharmacodynamics, Leiden, The Netherlands (E.M.T.v.M., T.J.v.S., M.J.A.); and Merck & Company, Inc., Kenilworth, New Jersey (M.S.M., M.J.S., M.E.K., H.J.K., J.S.)
| | - Maurice J Ahsman
- Division of Pharmacology, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands (E.M.T.v.M., M.D.); Leiden Experts on Advanced Pharmacokinetics and Pharmacodynamics, Leiden, The Netherlands (E.M.T.v.M., T.J.v.S., M.J.A.); and Merck & Company, Inc., Kenilworth, New Jersey (M.S.M., M.J.S., M.E.K., H.J.K., J.S.)
| | - Maria S Michener
- Division of Pharmacology, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands (E.M.T.v.M., M.D.); Leiden Experts on Advanced Pharmacokinetics and Pharmacodynamics, Leiden, The Netherlands (E.M.T.v.M., T.J.v.S., M.J.A.); and Merck & Company, Inc., Kenilworth, New Jersey (M.S.M., M.J.S., M.E.K., H.J.K., J.S.)
| | - Mary J Savage
- Division of Pharmacology, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands (E.M.T.v.M., M.D.); Leiden Experts on Advanced Pharmacokinetics and Pharmacodynamics, Leiden, The Netherlands (E.M.T.v.M., T.J.v.S., M.J.A.); and Merck & Company, Inc., Kenilworth, New Jersey (M.S.M., M.J.S., M.E.K., H.J.K., J.S.)
| | - Matthew E Kennedy
- Division of Pharmacology, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands (E.M.T.v.M., M.D.); Leiden Experts on Advanced Pharmacokinetics and Pharmacodynamics, Leiden, The Netherlands (E.M.T.v.M., T.J.v.S., M.J.A.); and Merck & Company, Inc., Kenilworth, New Jersey (M.S.M., M.J.S., M.E.K., H.J.K., J.S.)
| | - Huub Jan Kleijn
- Division of Pharmacology, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands (E.M.T.v.M., M.D.); Leiden Experts on Advanced Pharmacokinetics and Pharmacodynamics, Leiden, The Netherlands (E.M.T.v.M., T.J.v.S., M.J.A.); and Merck & Company, Inc., Kenilworth, New Jersey (M.S.M., M.J.S., M.E.K., H.J.K., J.S.)
| | - Julie Stone
- Division of Pharmacology, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands (E.M.T.v.M., M.D.); Leiden Experts on Advanced Pharmacokinetics and Pharmacodynamics, Leiden, The Netherlands (E.M.T.v.M., T.J.v.S., M.J.A.); and Merck & Company, Inc., Kenilworth, New Jersey (M.S.M., M.J.S., M.E.K., H.J.K., J.S.)
| | - Meindert Danhof
- Division of Pharmacology, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands (E.M.T.v.M., M.D.); Leiden Experts on Advanced Pharmacokinetics and Pharmacodynamics, Leiden, The Netherlands (E.M.T.v.M., T.J.v.S., M.J.A.); and Merck & Company, Inc., Kenilworth, New Jersey (M.S.M., M.J.S., M.E.K., H.J.K., J.S.)
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175
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Abstract
As a member of the A Disintegrin And Metalloproteinase (ADAM) family, ADAM10 has been identified as the constitutive α-secretase in the process of amyloid-β protein precursor (AβPP) cleavage and plays a critical role in reducing the generation of the amyloid-β (Aβ) peptides. Recent studies have demonstrated its beneficial role in alleviating the pathologic impairment in Alzheimer's disease (AD) both in vitro and in vivo. However, the role of ADAM10 in AD and the underlying molecular mechanisms are still not well established. Increasing evidence indicates that ADAM10 not only reduces the generation of Aβ but may also affect the pathology of AD through potential mechanisms including reducing tau pathology, maintaining normal synaptic functions, and promoting hippocampal neurogenesis and the homeostasis of neuronal networks. Mechanistically, ADAM10 regulates these functions by interacting with postsynaptic substrates in brain, especially synaptic cell receptors and adhesion molecules. Furthermore, ADAM10 protein in platelets seems to be a promising biomarker for AD diagnosis. This review will summarize the role of ADAM10 in AD and highlight its functions besides its role as the α-secretase in AβPP cleavage. Meanwhile, we will discuss the therapeutic potential of ADAM10 in treating AD.
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Affiliation(s)
- Xiang-Zhen Yuan
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China
| | - Sen Sun
- Qingdao Blood Center, Qingdao, China
| | - Chen-Chen Tan
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China
| | - Jin-Tai Yu
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China
| | - Lan Tan
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China
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176
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Beta-Site Amyloid Precursor Protein Cleaving Enzyme 1 Inhibition Impairs Synaptic Plasticity via Seizure Protein 6. Biol Psychiatry 2018; 83:428-437. [PMID: 28129943 DOI: 10.1016/j.biopsych.2016.12.023] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 12/01/2016] [Accepted: 12/16/2016] [Indexed: 12/21/2022]
Abstract
BACKGROUND Beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) is a promising drug target for the treatment of Alzheimer's disease. Prolonged BACE1 inhibition interferes with structural and functional synaptic plasticity in mice, most likely by altering the metabolism of BACE1 substrates. Seizure protein 6 (SEZ6) is predominantly cleaved by BACE1, and Sez6 knockout mice share some phenotypes with BACE1 inhibitor-treated mice. We investigated whether SEZ6 is involved in BACE1 inhibition-induced structural and functional synaptic alterations. METHODS The function of NB-360, a novel blood-brain barrier penetrant and orally available BACE1 inhibitor, was verified by immunoblotting. In vivo microscopy was applied to monitor the impact of long-term pharmacological BACE1 inhibition on dendritic spines in the cerebral cortex of constitutive and conditional Sez6 knockout mice. Finally, synaptic functions were characterized using electrophysiological field recordings in hippocampal slices. RESULTS BACE1 enzymatic activity was strongly suppressed by NB-360. Prolonged NB-360 treatment caused a reversible spine density reduction in wild-type mice, but it did not affect Sez6-/- mice. Knocking out Sez6 in a small subset of mature neurons also prevented the structural postsynaptic changes induced by BACE1 inhibition. Hippocampal long-term potentiation was decreased in both chronic BACE1 inhibitor-treated wild-type mice and vehicle-treated Sez6-/- mice. However, chronic NB-360 treatment did not alter long-term potentiation in CA1 neurons of Sez6-/- mice. CONCLUSIONS Our results suggest that SEZ6 plays an important role in maintaining normal dendritic spine dynamics. Furthermore, SEZ6 is involved in BACE1 inhibition-induced structural and functional synaptic alterations.
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177
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Chiang ACA, Fowler SW, Reddy R, Pletnikova O, Troncoso JC, Sherman MA, Lesne SE, Jankowsky JL. Discrete Pools of Oligomeric Amyloid-β Track with Spatial Learning Deficits in a Mouse Model of Alzheimer Amyloidosis. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 188:739-756. [PMID: 29248459 PMCID: PMC5840490 DOI: 10.1016/j.ajpath.2017.11.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 10/24/2017] [Accepted: 11/02/2017] [Indexed: 01/08/2023]
Abstract
Despite increasing appreciation that oligomeric amyloid-β (Aβ) may contribute to cognitive decline of Alzheimer disease, defining the most critical forms has been thwarted by the changeable nature of these aggregates and the varying methods used for detection. Herein, using a broad approach, we quantified Aβ oligomers during the evolution of cognitive deficits in an aggressive model of Aβ amyloidosis. Amyloid precursor protein/tetracycline transactivator mice underwent behavioral testing at 3, 6, 9, and 12 months of age to evaluate spatial learning and memory, followed by histologic assessment of amyloid burden and biochemical characterization of oligomeric Aβ species. Transgenic mice displayed progressive impairments in acquisition and immediate recall of the trained platform location. Biochemical analysis of cortical extracts from behaviorally tested mice revealed distinct age-dependent patterns of accumulation in multiple oligomeric species. Dot blot analysis demonstrated that nonfibrillar Aβ oligomers were highly soluble and extracted into a fraction enriched for extracellular proteins, whereas prefibrillar species required high-detergent conditions to retrieve, consistent with membrane localization. Low-detergent extracts tested by 82E1 enzyme-linked immunosorbent assay confirmed the presence of bona fide Aβ oligomers, whereas immunoprecipitation-Western blotting using high-detergent extracts revealed a variety of SDS-stable low-n species. These findings show that different Aβ oligomers vary in solubility, consistent with distinct localization, and identify nonfibrillar Aβ oligomer-positive aggregates as tracking most closely with cognitive decline in this model.
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Affiliation(s)
- Angie C A Chiang
- Department of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, Houston, Texas
| | - Stephanie W Fowler
- Department of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, Houston, Texas
| | - Rohit Reddy
- Department of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, Houston, Texas; Department of Cognitive Science, Rice University, Houston, Texas
| | - Olga Pletnikova
- Division of Neuropathology, Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Juan C Troncoso
- Division of Neuropathology, Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Mathew A Sherman
- Department of Neuroscience, N. Bud Grossman Center for Memory Research and Care, Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Sylvain E Lesne
- Department of Neuroscience, N. Bud Grossman Center for Memory Research and Care, Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Joanna L Jankowsky
- Department of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, Houston, Texas; Department of Neurology and Neurosurgery, Huffington Center on Aging, Baylor College of Medicine, Houston, Texas.
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178
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Lopez-Font I, Boix CP, Zetterberg H, Blennow K, Sáez-Valero J. Alterations in the Balance of Amyloid-β Protein Precursor Species in the Cerebrospinal Fluid of Alzheimer's Disease Patients. J Alzheimers Dis 2018; 57:1281-1291. [PMID: 28372336 DOI: 10.3233/jad-161275] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We recently demonstrated that soluble forms of the amyloid-β protein precursor (sAβPP) assemble into multimeric complexes in cerebrospinal fluid (CSF), which contributes to the underestimation of specific sAβPP species when assessed by ELISA. To circumvent this issue, we analyzed by SDS-PAGE large fragments of sAβPP and their variants in the CSF from Alzheimer's disease (AD; n = 20) and control (n = 20) subjects, probing with specific antibodies against particular domains. Similar levels of sAβPPα and sAβPPβ protein were found in CSF samples from AD and controls, yet there appeared to be a shift in the balance of the soluble full-length AβPP (sAβPPf) species in AD samples, with a decrease in the proportion of the lower (∼100 kDa) band relative to the upper (∼120 kDa) band. Similar differences were observed in the contribution of the major KPI-immunoreactive AβPP species. CSF samples also displayed differences in the correlations of AβPP species with classical AD biomarkers, particularly with respect to the Aβ42 peptide. The differences reveal alterations that probably reflect pathophysiological changes in the brain.
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Affiliation(s)
- Inmaculada Lopez-Font
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Claudia P Boix
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Henrik Zetterberg
- Clinical Neurochemistry Laboratory, Inst. of Neuroscience and Physiology, University of Gothenburg, Mölndal Campus, Sweden.,Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Kaj Blennow
- Clinical Neurochemistry Laboratory, Inst. of Neuroscience and Physiology, University of Gothenburg, Mölndal Campus, Sweden
| | - Javier Sáez-Valero
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
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179
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Kamikubo Y, Takasugi N, Niisato K, Hashimoto Y, Sakurai T. Consecutive Analysis of BACE1 Function on Developing and Developed Neuronal Cells. J Alzheimers Dis 2018; 56:641-653. [PMID: 28035928 DOI: 10.3233/jad-160806] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The amyloid-β protein precursor (AβPP) is cleaved by a transmembrane protease termed β-site AβPP cleavage enzyme (BACE1), which is being explored as a target for therapy and prevention of Alzheimer's disease (AD). Although genetic deletion of BACE1 results in abolished amyloid pathology in AD model mice, it also results in neurodevelopmental phenotypes such as hypomyelination and synaptic loss, observed in schizophrenia and autism-like phenotype. These lines of evidence indicate that the inhibition of BACE1 causes adverse side effects during the neurodevelopmental stage. However, the effects of the inhibition of BACE1 activity on already developed neurons remain unclear. Here, we utilized hippocampal slice cultures as an ex vivo model that enabled continuous and long-term analysis for the effect of BACE1 inhibition on neuronal circuits and synapses. Temporal changes in synaptic proteins in hippocampal slices indicated acute synaptic loss, followed by synapse formation and maintenance phases. Long-term BACE1 inhibition in the neurodevelopmental stage caused the loss of synaptic proteins but failed to alter synaptic proteins in the already developed maintenance stage. These data indicate that BACE1 function on synapses is dependent on synaptic developmental stages, and our study provides a useful model to observe the long-term effect of BACE1 activity in the brain, and to evaluate adverse effects of BACE inhibitors.
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180
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Voytyuk I, De Strooper B, Chávez-Gutiérrez L. Modulation of γ- and β-Secretases as Early Prevention Against Alzheimer's Disease. Biol Psychiatry 2018; 83:320-327. [PMID: 28918941 DOI: 10.1016/j.biopsych.2017.08.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 08/01/2017] [Accepted: 08/03/2017] [Indexed: 01/18/2023]
Abstract
The genetic evidence implicating amyloid-β in the initial stage of Alzheimer's disease is unequivocal. However, the long biochemical and cellular prodromal phases of the disease suggest that dementia is the result of a series of molecular and cellular cascades whose nature and connections remain unknown. Therefore, it is unlikely that treatments directed at amyloid-β will have major clinical effects in the later stages of the disease. We discuss the two major candidate therapeutic targets to lower amyloid-β in a preventive mode, i.e., γ- and β-secretase; the rationale behind these two targets; and the current state of the field.
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Affiliation(s)
- Iryna Voytyuk
- KU Leuven Department for Neurosciences, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | - Bart De Strooper
- KU Leuven Department for Neurosciences, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium; UK Dementia Research Institute, University College, London, United Kingdom.
| | - Lucía Chávez-Gutiérrez
- KU Leuven Department for Neurosciences, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
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181
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Styr B, Slutsky I. Imbalance between firing homeostasis and synaptic plasticity drives early-phase Alzheimer's disease. Nat Neurosci 2018; 21:463-473. [PMID: 29403035 DOI: 10.1038/s41593-018-0080-x] [Citation(s) in RCA: 186] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/08/2018] [Indexed: 12/18/2022]
Abstract
During recent years, the preclinical stage of Alzheimer's disease (AD) has become a major focus of research. Continued failures in clinical trials and the realization that early intervention may offer better therapeutic outcome triggered a conceptual shift from late-stage AD pathology to early-stage pathophysiology. While much effort has been directed at understanding the factors initiating AD, little is known about the principle basis underlying the disease progression at its early stages. In this Perspective, we suggest a hypothesis to explain the transition from 'silent' signatures of aberrant neural circuit activity to clinically evident memory impairments. Namely, we propose that failures in firing homeostasis and imbalance between firing stability and synaptic plasticity in cortico-hippocampal circuits represent the driving force of early disease progression. We analyze the main types of possible homeostatic failures and provide the essential conceptual framework for examining the causal link between dysregulation of firing homeostasis, aberrant neural circuit activity and memory-related plasticity impairments associated with early AD.
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Affiliation(s)
- Boaz Styr
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Inna Slutsky
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. .,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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182
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Geerts H, Spiros A, Roberts P. Impact of amyloid-beta changes on cognitive outcomes in Alzheimer's disease: analysis of clinical trials using a quantitative systems pharmacology model. Alzheimers Res Ther 2018; 10:14. [PMID: 29394903 PMCID: PMC5797372 DOI: 10.1186/s13195-018-0343-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 01/15/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND Despite a tremendous amount of information on the role of amyloid in Alzheimer's disease (AD), almost all clinical trials testing this hypothesis have failed to generate clinically relevant cognitive effects. METHODS We present an advanced mechanism-based and biophysically realistic quantitative systems pharmacology computer model of an Alzheimer-type neuronal cortical network that has been calibrated with Alzheimer Disease Assessment Scale, cognitive subscale (ADAS-Cog) readouts from historical clinical trials and simulated the differential impact of amyloid-beta (Aβ40 and Aβ42) oligomers on glutamate and nicotinic neurotransmission. RESULTS Preclinical data suggest a beneficial effect of shorter Aβ forms within a limited dose range. Such a beneficial effect of Aβ40 on glutamate neurotransmission in human patients is absolutely necessary to reproduce clinical data on the ADAS-Cog in minimal cognitive impairment (MCI) patients with and without amyloid load, the effect of APOE genotype effect on the slope of the cognitive trajectory over time in placebo AD patients and higher sensitivity to cholinergic manipulation with scopolamine associated with higher Aβ in MCI subjects. We further derive a relationship between units of Aβ load in our model and the standard uptake value ratio from amyloid imaging. When introducing the documented clinical pharmacodynamic effects on Aβ levels for various amyloid-related clinical interventions in patients with low Aβ baseline, the platform predicts an overall significant worsening for passive vaccination with solanezumab, beta-secretase inhibitor verubecestat and gamma-secretase inhibitor semagacestat. In contrast, all three interventions improved cognition in subjects with moderate to high baseline Aβ levels, with verubecestat anticipated to have the greatest effect (around ADAS-Cog value 1.5 points), solanezumab the lowest (0.8 ADAS-Cog value points) and semagacestat in between. This could explain the success of many amyloid interventions in transgene animals with an artificial high level of Aβ, but not in AD patients with a large variability of amyloid loads. CONCLUSIONS If these predictions are confirmed in post-hoc analyses of failed clinical amyloid-modulating trials, one should question the rationale behind testing these interventions in early and prodromal subjects with low or zero amyloid load.
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Affiliation(s)
- Hugo Geerts
- In Silico Biosciences, 686 Westwind Dr, Berwyn, PA, 1312, USA.
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Athan Spiros
- In Silico Biosciences, 686 Westwind Dr, Berwyn, PA, 1312, USA
| | - Patrick Roberts
- In Silico Biosciences, 686 Westwind Dr, Berwyn, PA, 1312, USA
- Amazon AI AWS, Portland, OR, USA
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183
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Yan Y, Dominguez S, Fisher DW, Dong H. Sex differences in chronic stress responses and Alzheimer's disease. Neurobiol Stress 2018; 8:120-126. [PMID: 29888307 PMCID: PMC5991323 DOI: 10.1016/j.ynstr.2018.03.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 02/10/2018] [Accepted: 03/17/2018] [Indexed: 11/13/2022] Open
Abstract
Clinical studies indicate that Alzheimer's disease (AD) disproportionately affects women in both disease prevalence and severity, but the mechanisms underlying this sex divergence are unknown. Though some have suggested this difference in risk is a reflection of known differences in longevity between men and women, mounting clinical and preclinical evidence supports women also having intrinsic susceptibilities towards the disease. While a number of potential risk factors have been hypothesized to affect these differences in risks, none have been definitively verified. In this review, we discuss a novel hypothesis whereby women's susceptibility to chronic stress also mediates increased risk for AD. As stress is a risk factor for AD, and women are twice as likely to develop mood disorders where stress is a major etiology, it is possible that sex dimorphisms in stress responses contribute to the increase in women with AD. In line with this, sex divergence in biochemical responses to stress have been noted along the hypothalamic-pituitary-adrenal (HPA) axis and among known molecular effectors of AD, with crosstalk between these processes also being likely. In addition, activation of the cortical corticotrophin-releasing factor receptor 1 (CRF1) signaling pathway leads to distinct female-biased increases in molecules associated with AD pathogenesis. Therefore, the different biochemical responses to stress between women and men may represent an intrinsic, sex-dependent risk factor for AD.
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Affiliation(s)
- Yan Yan
- Department of Psychiatry & Behavioral Sciences, Northwestern University, Feinberg School of Medicine, 303 East Chicago Avenue, Chicago, IL 60611, USA
- Department of Physiology, Zunyi Medical University, Zunyi Guizhou 563099, China
| | - Sky Dominguez
- Department of Psychiatry & Behavioral Sciences, Northwestern University, Feinberg School of Medicine, 303 East Chicago Avenue, Chicago, IL 60611, USA
| | - Daniel W. Fisher
- Department of Neurology, Northwestern University, Feinberg School of Medicine, 303 East Chicago Avenue, Chicago, IL 60611, USA
| | - Hongxin Dong
- Department of Psychiatry & Behavioral Sciences, Northwestern University, Feinberg School of Medicine, 303 East Chicago Avenue, Chicago, IL 60611, USA
- Department of Physiology, Zunyi Medical University, Zunyi Guizhou 563099, China
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184
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Laulagnier K, Javalet C, Hemming FJ, Chivet M, Lachenal G, Blot B, Chatellard C, Sadoul R. Amyloid precursor protein products concentrate in a subset of exosomes specifically endocytosed by neurons. Cell Mol Life Sci 2018; 75:757-773. [PMID: 28956068 PMCID: PMC11105273 DOI: 10.1007/s00018-017-2664-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 08/31/2017] [Accepted: 09/20/2017] [Indexed: 12/15/2022]
Abstract
Amyloid beta peptide (Aβ), the main component of senile plaques of Alzheimer's disease brains, is produced by sequential cleavage of amyloid precursor protein (APP) and of its C-terminal fragments (CTFs). An unanswered question is how amyloidogenic peptides spread throughout the brain during the course of the disease. Here, we show that small lipid vesicles called exosomes, secreted in the extracellular milieu by cortical neurons, carry endogenous APP and are strikingly enriched in CTF-α and the newly characterized CTF-η. Exosomes from N2a cells expressing human APP with the autosomal dominant Swedish mutation contain Aβ peptides as well as CTF-α and CTF-η, while those from cells expressing the non-mutated form of APP only contain CTF-α and CTF-η. APP and CTFs are sorted into a subset of exosomes which lack the tetraspanin CD63 and specifically bind to dendrites of neurons, unlike exosomes carrying CD63 which bind to both neurons and glial cells. Thus, neuroblastoma cells secrete distinct populations of exosomes carrying different cargoes and targeting specific cell types. APP-carrying exosomes can be endocytosed by receiving cells, allowing the processing of APP acquired by exosomes to give rise to the APP intracellular domain (AICD). Thus, our results show for the first time that neuronal exosomes may indeed act as vehicles for the intercellular transport of APP and its catabolites.
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Affiliation(s)
- Karine Laulagnier
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France.
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France.
| | - Charlotte Javalet
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France
| | - Fiona J Hemming
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France
| | - Mathilde Chivet
- Dulbecco Telethon Institute Lab of Neurodegenerative Diseases, Centre for Integrative Biology (CIBIO), University of Trento, 38123, Trento, Italy
| | - Gaëlle Lachenal
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France
| | - Béatrice Blot
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France
| | - Christine Chatellard
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France
| | - Rémy Sadoul
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France.
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France.
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185
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Role of Amyloid Precursor Protein (APP) and Its Derivatives in the Biology and Cell Fate Specification of Neural Stem Cells. Mol Neurobiol 2018; 55:7107-7117. [DOI: 10.1007/s12035-018-0914-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/18/2018] [Indexed: 01/31/2023]
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186
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Jang JY, Rhim H, Kang S. NABi, a novel β-sheet breaker, inhibits Aβ aggregation and neuronal toxicity: Therapeutic implications for Alzheimer's disease. Biochim Biophys Acta Gen Subj 2018; 1862:71-80. [DOI: 10.1016/j.bbagen.2017.10.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 10/18/2017] [Accepted: 10/24/2017] [Indexed: 01/08/2023]
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187
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Hunter S, Brayne C. Understanding the roles of mutations in the amyloid precursor protein in Alzheimer disease. Mol Psychiatry 2018; 23:81-93. [PMID: 29112196 DOI: 10.1038/mp.2017.218] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 08/23/2017] [Accepted: 08/24/2017] [Indexed: 12/16/2022]
Abstract
Many models of disease progression in Alzheimer's disease (AD) have been proposed to help guide experimental design and aid the interpretation of results. Models focussing on the genetic evidence include the amyloid cascade (ACH) and presenilin (PSH) hypotheses and the amyloid precursor protein (APP) matrix approach (AMA), of which the ACH has held a dominant position for over two decades. However, the ACH has never been fully accepted and has not yet delivered on its therapeutic promise. We review the ACH, PSH and AMA in relation to levels of APP proteolytic fragments reported from AD-associated mutations in APP. Different APP mutations have diverse effects on the levels of APP proteolytic fragments. This evidence is consistent with at least three disease pathways that can differ between familial and sporadic AD and two pathways associated with cerebral amyloid angiopathy. We cannot fully evaluate the ACH, PSH and AMA in relation to the effects of mutations in APP as the APP proteolytic system has not been investigated systematically. The confounding effects of sequence homology, complexity of competing cleavages and antibody cross reactivities all illustrate limitations in our understanding of the roles these fragments and the APP proteolytic system as a whole in normal aging and disease play. Current experimental design should be refined to generate clearer evidence, addressing both aging and complex disorders with standardised reporting formats. A more flexible theoretical framework capable of accommodating the complexity of the APP proteolytic system is required to integrate available evidence.
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Affiliation(s)
- S Hunter
- Department of Public Health and Primary Care, Institute of Public Health, Forvie Site University of Cambridge, School of Clinical Medicine, Cambridge, UK
| | - C Brayne
- Department of Public Health and Primary Care, Institute of Public Health, Forvie Site University of Cambridge, School of Clinical Medicine, Cambridge, UK
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188
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Doig AJ. Positive Feedback Loops in Alzheimer's Disease: The Alzheimer's Feedback Hypothesis. J Alzheimers Dis 2018; 66:25-36. [PMID: 30282364 PMCID: PMC6484277 DOI: 10.3233/jad-180583] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2018] [Indexed: 12/17/2022]
Abstract
The dominant model for Alzheimer's disease (AD) is the amyloid cascade hypothesis, in which the accumulation of excess amyloid-β (Aβ) leads to inflammation, excess glutamate and intracellular calcium, oxidative stress, tau hyperphosphorylation and tangle formation, neuronal loss, and ultimately dementia. In a cascade, AD proceeds in a unidirectional fashion, with events only affecting downstream processes. Compelling evidence now exists for the presence of positive feedback loops in AD, however, involving oxidative stress, inflammation, glutamate, calcium, and tau. The pathological state of AD is thus a system of positive feedback loops, leading to amplification of the initial perturbation, rather than a linear cascade. Drugs may therefore be effective by targeting numerous points within the loops, rather than concentrating on upstream processes. Anti-inflammatories and anti-oxidants may be especially valuable, since these processes are involved in many loops and hence would affect numerous processes in AD.
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Affiliation(s)
- Andrew J. Doig
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology Medicine and Health, Oxford Road, University of Manchester, UK
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189
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Bate C, Williams A. Monomeric amyloid-β reduced amyloid-β oligomer-induced synapse damage in neuronal cultures. Neurobiol Dis 2017; 111:48-58. [PMID: 29272738 DOI: 10.1016/j.nbd.2017.12.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 11/12/2017] [Accepted: 12/12/2017] [Indexed: 12/25/2022] Open
Abstract
Alzheimer's disease is a progressive neurodegenerative disease characterized by the accumulation of amyloid-β (Aβ) in the brain. Aβ oligomers are believed to cause synapse damage resulting in the memory deficits that are characteristic of this disease. Since the loss of synaptic proteins in the brain correlates closely with the degree of dementia in Alzheimer's disease, the process of Aβ-induced synapse damage was investigated in cultured neurons by measuring the loss of synaptic proteins. Soluble Aβ oligomers, derived from Alzheimer's-affected brains, caused the loss of cysteine string protein and synaptophysin from neurons. When applied to synaptosomes Aβ oligomers increased cholesterol concentrations and caused aberrant activation of cytoplasmic phospholipase A2 (cPLA2). In contrast, Aβ monomer preparations did not affect cholesterol concentrations or activate synaptic cPLA2, nor did they damage synapses. The Aβ oligomer-induced aggregation of cellular prion proteins (PrPC) at synapses triggered the activation of cPLA2 that leads to synapse degeneration. Critically, Aβ monomer preparations did not cause the aggregation of PrPC; rather they reduced the Aβ oligomer-induced aggregation of PrPC. The presence of Aβ monomer preparations also inhibited the Aβ oligomer-induced increase in cholesterol concentrations and activation of cPLA2 in synaptosomes and protected neurons against the Aβ oligomer-induced synapse damage. These results support the hypothesis that Aβ monomers are neuroprotective. We hypothesise that synapse damage may result from a pathological Aβ monomer:oligomer ratio rather than the total concentrations of Aβ within the brain.
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Affiliation(s)
- Clive Bate
- Department of Pathology and Pathogen Biology, Royal Veterinary College, Hawkshead Lane, North Mymms, Herts AL9 7TA, UK.
| | - Alun Williams
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK.
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190
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Boziki M, Polyzos SA, Deretzi G, Kazakos E, Katsinelos P, Doulberis M, Kotronis G, Giartza-Taxidou E, Laskaridis L, Tzivras D, Vardaka E, Kountouras C, Grigoriadis N, Thomann R, Kountouras J. A potential impact of Helicobacter pylori-related galectin-3 in neurodegeneration. Neurochem Int 2017; 113:137-151. [PMID: 29246761 DOI: 10.1016/j.neuint.2017.12.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/03/2017] [Accepted: 12/11/2017] [Indexed: 02/07/2023]
Abstract
Neurodegeneration represents a component of the central nervous system (CNS) diseases pathogenesis, either as a disability primary source in the frame of prototype neurodegenerative disorders, or as a secondary effect, following inflammation, hypoxia or neurotoxicity. Galectins are members of the lectin superfamily, a group of endogenous glycan-binding proteins, able to interact with glycosylated receptors expressed by several immune cell types. Glycan-lectin interactions play critical roles in the living systems by involving and mediating a variety of biologically important normal and pathological processes, including cell-cell signaling shaping cell communication, proliferation and migration, immune responses and fertilization, host-pathogen interactions and diseases such as neurodegenerative disorders and tumors. This review focuses in the role of Galectin-3 in shaping responses of the immune system against microbial agents, and concretely, Helicobacter pylori (Hp), thereby potentiating effect of the microbe in areas distant from the ordinary site of colonization, like the CNS. We hereby postulate that gastrointestinal Hp alterations in terms of immune cell functional phenotype, cytokine and chemokine secretion, may trigger systemic responses, thereby conferring implications for remote processes susceptible in immunity disequilibrium, namely, the CNS inflammation and/or neurodegeneration.
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Affiliation(s)
- Marina Boziki
- Department of Medicine, Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece; Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Stergios A Polyzos
- Department of Medicine, Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece
| | - Georgia Deretzi
- Department of Neurology, Multiple Sclerosis Unit, Papageorgiou Hospital, Thessaloniki, Greece
| | - Evangelos Kazakos
- Department of Medicine, Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece
| | - Panagiotis Katsinelos
- Department of Medicine, Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece
| | - Michael Doulberis
- Department of Medicine, Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece; Department of Internal Medicine, Bürgerspital Solothurn, Solothurn, Switzerland
| | - Georgios Kotronis
- Department of Medicine, Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece
| | - Evaggelia Giartza-Taxidou
- Department of Medicine, Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece
| | - Leonidas Laskaridis
- Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Dimitri Tzivras
- Department of Medicine, Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece
| | - Elisabeth Vardaka
- Department of Medicine, Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece
| | - Constantinos Kountouras
- Department of Medicine, Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece
| | - Nikolaos Grigoriadis
- Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Robert Thomann
- Department of Internal Medicine, Bürgerspital Solothurn, Solothurn, Switzerland
| | - Jannis Kountouras
- Department of Medicine, Second Medical Clinic, Aristotle University of Thessaloniki, Ippokration Hospital, Thessaloniki, Greece.
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191
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HIV-1 counteracts an innate restriction by amyloid precursor protein resulting in neurodegeneration. Nat Commun 2017; 8:1522. [PMID: 29142315 PMCID: PMC5688069 DOI: 10.1038/s41467-017-01795-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 10/16/2017] [Indexed: 12/19/2022] Open
Abstract
While beta-amyloid (Aβ), a classic hallmark of Alzheimer's disease (AD) and dementia, has long been known to be elevated in the human immunodeficiency virus type 1 (HIV-1)-infected brain, why and how Aβ is produced, along with its contribution to HIV-associated neurocognitive disorder (HAND) remains ill-defined. Here, we reveal that the membrane-associated amyloid precursor protein (APP) is highly expressed in macrophages and microglia, and acts as an innate restriction against HIV-1. APP binds the HIV-1 Gag polyprotein, retains it in lipid rafts and blocks HIV-1 virion production and spread. To escape this restriction, Gag promotes secretase-dependent cleavage of APP, resulting in the overproduction of toxic Aβ isoforms. This Gag-mediated Aβ production results in increased degeneration of primary cortical neurons, and can be prevented by γ-secretase inhibitor treatment. Interfering with HIV-1's evasion of APP-mediated restriction also suppresses HIV-1 spread, offering a potential strategy to both treat infection and prevent HAND.
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192
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Prostaglandin J2 promotes O-GlcNAcylation raising APP processing by α- and β-secretases: relevance to Alzheimer's disease. Neurobiol Aging 2017; 62:130-145. [PMID: 29149631 DOI: 10.1016/j.neurobiolaging.2017.10.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 09/26/2017] [Accepted: 10/11/2017] [Indexed: 12/19/2022]
Abstract
Regulation of the amyloid precursor protein (APP) processing by α- and β-secretases is of special interest to Alzheimer's disease (AD), as these proteases prevent or mediate amyloid beta formation, respectively. Neuroinflammation is also implicated in AD. Our data demonstrate that the endogenous mediator of inflammation prostaglandin J2 (PGJ2) promotes full-length APP (FL-APP) processing by α- and β-secretases. The decrease in FL-APP was independent of proteasomal, lysosomal, calpain, caspase, and γ-secretase activities. Moreover, PGJ2-treatment promoted cleavage of secreted APP, specifically sAPPα and sAPPβ, generated by α and β-secretase, respectively. Notably, PGJ2-treatment induced caspase-dependent cleavage of sAPPβ. Mechanistically, PGJ2-treatment selectively diminished mature (O- and N-glycosylated) but not immature (N-glycosylated only) FL-APP. PGJ2-treatment also increased the overall levels of protein O-GlcNAcylation, which occurs within the nucleocytoplasmic compartment. It is known that APP undergoes O-GlcNAcylation and that the latter protects proteins from proteasomal degradation. Our results suggest that by increasing protein O-GlcNAcylation levels, PGJ2 renders mature APP less prone to proteasomal degradation, thus shunting APP toward processing by α- and β-secretases.
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193
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Human Brain-Derived Aβ Oligomers Bind to Synapses and Disrupt Synaptic Activity in a Manner That Requires APP. J Neurosci 2017; 37:11947-11966. [PMID: 29101243 DOI: 10.1523/jneurosci.2009-17.2017] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 09/19/2017] [Accepted: 09/29/2017] [Indexed: 12/20/2022] Open
Abstract
Compelling genetic evidence links the amyloid precursor protein (APP) to Alzheimer's disease (AD) and several theories have been advanced to explain the relationship. A leading hypothesis proposes that a small amphipathic fragment of APP, the amyloid β-protein (Aβ), self-associates to form soluble aggregates that impair synaptic and network activity. Here, we used the most disease-relevant form of Aβ, protein isolated from AD brain. Using this material, we show that the synaptotoxic effects of Aβ depend on expression of APP and that the Aβ-mediated impairment of synaptic plasticity is accompanied by presynaptic effects that disrupt the excitatory/inhibitory (E/I) balance. The net increase in the E/I ratio and inhibition of plasticity are associated with Aβ localizing to synapses and binding of soluble Aβ aggregates to synapses requires the expression of APP. Our findings indicate a role for APP in AD pathogenesis beyond the generation of Aβ and suggest modulation of APP expression as a therapy for AD.SIGNIFICANCE STATEMENT Here, we report on the plasticity-disrupting effects of amyloid β-protein (Aβ) isolated from Alzheimer's disease (AD) brain and the requirement of amyloid precursor protein (APP) for these effects. We show that Aβ-containing AD brain extracts block hippocampal LTP, augment glutamate release probability, and disrupt the excitatory/inhibitory balance. These effects are associated with Aβ localizing to synapses and genetic ablation of APP prevents both Aβ binding and Aβ-mediated synaptic dysfunctions. Our results emphasize the importance of APP in AD and should stimulate new studies to elucidate APP-related targets suitable for pharmacological manipulation.
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194
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Baranger K, Giannoni P, Girard SD, Girot S, Gaven F, Stephan D, Migliorati M, Khrestchatisky M, Bockaert J, Marchetti-Gauthier E, Rivera S, Claeysen S, Roman FS. Chronic treatments with a 5-HT 4 receptor agonist decrease amyloid pathology in the entorhinal cortex and learning and memory deficits in the 5xFAD mouse model of Alzheimer's disease. Neuropharmacology 2017; 126:128-141. [DOI: 10.1016/j.neuropharm.2017.08.031] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 07/25/2017] [Accepted: 08/22/2017] [Indexed: 12/11/2022]
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195
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Yang H, Wang Y, Kar S. Effects of cholesterol transport inhibitor U18666A on APP metabolism in rat primary astrocytes. Glia 2017; 65:1728-1743. [PMID: 28722194 DOI: 10.1002/glia.23191] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 12/21/2022]
Abstract
Amyloid β (Aβ) peptides generated from the amyloid precursor protein (APP) play an important role in the degeneration of neurons and development of Alzheimer's disease (AD). Current evidence indicates that high levels of cholesterol-which increase the risk of developing AD-can influence Aβ production in neurons. However, it remains unclear how altered level/subcellular distribution of cholesterol in astrocytes can influence APP metabolism. In this study, we evaluated the effects of cholesterol transport inhibitor U18666A-a class II amphiphile that triggers redistribution of cholesterol within the endosomal-lysosomal (EL) system-on APP levels and metabolism in rat primary cultured astrocytes. Our results revealed that U18666A increased the levels of the APP holoprotein and its cleaved products (α-/β-/η-CTFs) in cultured astrocytes, without altering the total levels of cholesterol or cell viability. The cellular levels of Aβ1-40 were also found to be markedly increased, while secretory levels of Aβ1-40 were decreased in U18666A-treated astrocytes. We further report a corresponding increase in the activity of the enzymes regulating APP processing, such as α-secretase, β-secretase, and γ-secretase as a consequence of U18666A treatment. Additionally, APP-cleaved products are partly accumulated in the lysosomes following cholesterol sequestration within EL system possibly due to decreased clearance. Interestingly, serum delipidation attenuated enhanced levels of APP and its cleaved products following U18666A treatment. Collectively, these results suggest that cholesterol sequestration within the EL system in astrocytes can influence APP metabolism and the accumulation of APP-cleaved products including Aβ peptides, which can contribute to the development of AD pathology.
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Affiliation(s)
- Hongyan Yang
- Department of Psychiatry, Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, T6G 2M8, Canada
- Department of Pharmacology, Qiqihar Medical University, Qiqihar, Heilongjiang, China
| | - Yanlin Wang
- Department of Psychiatry, Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, T6G 2M8, Canada
| | - Satyabrata Kar
- Department of Psychiatry, Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, T6G 2M8, Canada
- Department of Medicine, Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, T6G 2M8, Canada
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196
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Roher AE, Kokjohn TA, Clarke SG, Sierks MR, Maarouf CL, Serrano GE, Sabbagh MS, Beach TG. APP/Aβ structural diversity and Alzheimer's disease pathogenesis. Neurochem Int 2017; 110:1-13. [PMID: 28811267 PMCID: PMC5688956 DOI: 10.1016/j.neuint.2017.08.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/25/2017] [Accepted: 08/11/2017] [Indexed: 02/01/2023]
Abstract
The amyloid cascade hypothesis of Alzheimer's disease (AD) proposes amyloid- β (Aβ) is a chief pathological element of dementia. AD therapies have targeted monomeric and oligomeric Aβ 1-40 and 1-42 peptides. However, alternative APP proteolytic processing produces a complex roster of Aβ species. In addition, Aβ peptides are subject to extensive posttranslational modification (PTM). We propose that amplified production of some APP/Aβ species, perhaps exacerbated by differential gene expression and reduced peptide degradation, creates a diverse spectrum of modified species which disrupt brain homeostasis and accelerate AD neurodegeneration. We surveyed the literature to catalog Aβ PTM including species with isoAsp at positions 7 and 23 which may phenocopy the Tottori and Iowa Aβ mutations that result in early onset AD. We speculate that accumulation of these alterations induce changes in secondary and tertiary structure of Aβ that favor increased toxicity, and seeding and propagation in sporadic AD. Additionally, amyloid-β peptides with a pyroglutamate modification at position 3 and oxidation of Met35 make up a substantial portion of sporadic AD amyloid deposits. The intrinsic physical properties of these species, including resistance to degradation, an enhanced aggregation rate, increased neurotoxicity, and association with behavioral deficits, suggest their emergence is linked to dementia. The generation of specific 3D-molecular conformations of Aβ impart unique biophysical properties and a capacity to seed the prion-like global transmission of amyloid through the brain. The accumulation of rogue Aβ ultimately contributes to the destruction of vascular walls, neurons and glial cells culminating in dementia. A systematic examination of Aβ PTM and the analysis of the toxicity that they induced may help create essential biomarkers to more precisely stage AD pathology, design countermeasures and gauge the impacts of interventions.
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Affiliation(s)
- Alex E Roher
- Division of Neurobiology, Barrow Neurological Institute, Phoenix, AZ 85013, USA; Division of Clinical Education, Midwestern University, Glendale, AZ 85308, USA.
| | - Tyler A Kokjohn
- Department of Microbiology, Midwestern University, Glendale, AZ 85308, USA
| | - Steven G Clarke
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California, Los Angeles, Los Angeles CA 90095-1569, USA
| | - Michael R Sierks
- Department of Chemical Engineering, Arizona State University, Tempe, AZ 85287-6106, USA
| | - Chera L Maarouf
- Laboratory of Neuropathology, Banner Sun Health Research Institute, Sun City, AZ 85351, USA
| | - Geidy E Serrano
- Laboratory of Neuropathology, Banner Sun Health Research Institute, Sun City, AZ 85351, USA
| | - Marwan S Sabbagh
- Alzheimer's and Memory Disorders Division, Barrow Neurological Institute, Phoenix, AZ 85013, USA
| | - Thomas G Beach
- Laboratory of Neuropathology, Banner Sun Health Research Institute, Sun City, AZ 85351, USA
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197
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Amendments and Corrections to Mattusch et al. (Anesthesiology 2015; 122[5]:1047–59), “Impact of Hyperpolarization-activated, Cyclic Nucleotide-gated Cation Channel Type 2 for the Xenon-mediated Anesthetic Effect: Evidence from In Vitro and In Vivo Experiments”. Anesthesiology 2017; 127:905-910. [DOI: 10.1097/aln.0000000000001830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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198
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Distinct amyloid precursor protein processing machineries of the olfactory system. Biochem Biophys Res Commun 2017; 495:533-538. [PMID: 29097202 DOI: 10.1016/j.bbrc.2017.10.153] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 10/28/2017] [Indexed: 11/21/2022]
Abstract
Processing of amyloid precursor protein (APP) occurs through sequential cleavages first by β-secretase and then by the γ-secretase complex. However, abnormal processing of APP leads to excessive production of β-amyloid (Aβ) in the central nervous system (CNS), an event which is regarded as a primary cause of Alzheimer's disease (AD). In particular, gene mutations of the γ-secretase complex-which contains presenilin 1 or 2 as the catalytic core-could trigger marked Aβ accumulation. Olfactory dysfunction usually occurs before the onset of typical AD-related symptoms (eg, memory loss or muscle retardation), suggesting that the olfactory system may be one of the most vulnerable regions to AD. To date however, little is known about why the olfactory system is affected so early by AD prior to other regions. Thus, we examined the distribution of secretases and levels of APP processing in the olfactory system under either healthy or pathological conditions. Here, we show that the olfactory system has distinct APP processing machineries. In particular, we identified higher expressions levels and activity of γ-secretase in the olfactory epithelium (OE) than other regions of the brain. Moreover, APP c-terminal fragments (CTF) are markedly detected. During AD progression, we note increased expression of presenilin2 of γ-secretases in the OE, not in the OB, and show that neurotoxic Aβ*56 accumulates more quickly in the OE. Taken together, these results suggest that the olfactory system has distinct APP processing machineries under healthy and pathological conditions. This finding may provide a crucial understanding of the unique APP-processing mechanisms in the olfactory system, and further highlights the correlation between olfactory deficits and AD symptoms.
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199
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Trafficking in Alzheimer's Disease: Modulation of APP Transport and Processing by the Transmembrane Proteins LRP1, SorLA, SorCS1c, Sortilin, and Calsyntenin. Mol Neurobiol 2017; 55:5809-5829. [PMID: 29079999 DOI: 10.1007/s12035-017-0806-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/17/2017] [Indexed: 12/11/2022]
Abstract
The amyloid precursor protein (APP), one key player in Alzheimer's disease (AD), is extensively processed by different proteases. This leads to the generation of diverging fragments including the amyloid β (Aβ) peptide, which accumulates in brains of AD patients. Subcellular trafficking of APP is an important aspect for its proteolytic conversion, since the various secretases which cleave APP are located in different cellular compartments. As a consequence, altered subcellular targeting of APP is thought to directly affect the degree to which Aβ is generated. The mechanisms underlying intracellular APP transport are critical to understand AD pathogenesis and can serve as a target for future pharmacological interventions. In the recent years, a number of APP interacting proteins were identified which are implicated in sorting of APP, thereby influencing APP processing at different angles of the secretory or endocytic pathway. This review provides an update on the proteolytic processing of APP and the interplay of the transmembrane proteins low-density lipoprotein receptor-related protein 1, sortilin-receptor with A-type repeats, SorCS1c, sortilin, and calsyntenin. We discuss the specific interactions with APP, the capacity to modulate the intracellular itinerary and the proteolytic conversion of APP, a possible involvement in the clearance of Aβ, and the implications of these transmembrane proteins in AD and other neurodegenerative diseases.
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200
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Widagdo J, Guntupalli S, Jang SE, Anggono V. Regulation of AMPA Receptor Trafficking by Protein Ubiquitination. Front Mol Neurosci 2017; 10:347. [PMID: 29123470 PMCID: PMC5662755 DOI: 10.3389/fnmol.2017.00347] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 10/12/2017] [Indexed: 11/27/2022] Open
Abstract
The molecular mechanisms underlying plastic changes in the strength and connectivity of excitatory synapses have been studied extensively for the past few decades and remain the most attractive cellular models of learning and memory. One of the major mechanisms that regulate synaptic plasticity is the dynamic adjustment of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptor content on the neuronal plasma membrane. The expression of surface AMPA receptors (AMPARs) is controlled by the delicate balance between the biosynthesis, dendritic transport, exocytosis, endocytosis, recycling and degradation of the receptors. These processes are dynamically regulated by AMPAR interacting proteins as well as by various post-translational modifications that occur on their cytoplasmic domains. In the last few years, protein ubiquitination has emerged as a major regulator of AMPAR intracellular trafficking. Dysregulation of AMPAR ubiquitination has also been implicated in the pathophysiology of Alzheimer’s disease. Here we review recent advances in the field and provide insights into the role of protein ubiquitination in regulating AMPAR membrane trafficking and function. We also discuss how aberrant ubiquitination of AMPARs contributes to the pathogenesis of various neurological disorders, including Alzheimer’s disease, chronic stress and epilepsy.
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Affiliation(s)
- Jocelyn Widagdo
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Sumasri Guntupalli
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Se E Jang
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Victor Anggono
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
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