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Arber C, Belder CRS, Tomczuk F, Gabriele R, Buhidma Y, Farrell C, O'Connor A, Rice H, Lashley T, Fox NC, Ryan NS, Wray S. The presenilin 1 mutation P436S causes familial Alzheimer's disease with elevated Aβ43 and atypical clinical manifestations. Alzheimers Dement 2024. [PMID: 38824433 DOI: 10.1002/alz.13904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 04/22/2024] [Accepted: 04/24/2024] [Indexed: 06/03/2024]
Abstract
INTRODUCTION Familial Alzheimer's disease (fAD) is heterogeneous in terms of age at onset and clinical presentation. A greater understanding of the pathogenicity of fAD variants and how these contribute to heterogeneity will enhance our understanding of the mechanisms of AD more widely. METHODS To determine the pathogenicity of the unclassified PSEN1 P436S mutation, we studied an expanded kindred of eight affected individuals, with magnetic resonance imaging (MRI) (two individuals), patient-derived induced pluripotent stem cell (iPSC) models (two donors), and post-mortem histology (one donor). RESULTS An autosomal dominant pattern of inheritance of fAD was seen, with an average age at symptom onset of 46 years and atypical features. iPSC models and post-mortem tissue supported high production of amyloid beta 43 (Aβ43). PSEN1 peptide maturation was unimpaired. DISCUSSION We confirm that the P436S mutation in PSEN1 causes atypical fAD. The location of the mutation in the critical PSEN1 proline-alanine-leucine-proline (PALP) motif may explain the early age at onset despite appropriate protein maturation. HIGHLIGHTS PSEN1 P436S mutations cause familial Alzheimer's disease. This mutation is associated with atypical clinical presentation. Induced pluripotent stem cells (iPSCs) and post-mortem studies support increased amyloid beta (Aβ43) production. Early age at onset highlights the importance of the PALP motif in PSEN1 function.
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Affiliation(s)
- Charles Arber
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Christopher R S Belder
- Dementia Research Centre, UCL Queen Square Institute of Neurology, London, UK
- UCL Queen Square Institute of Neurology, UK Dementia Research Institute at UCL, London, UK
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Filip Tomczuk
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Rebecca Gabriele
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Yazead Buhidma
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Clíona Farrell
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
- UCL Queen Square Institute of Neurology, UK Dementia Research Institute at UCL, London, UK
| | - Antoinette O'Connor
- Dementia Research Centre, UCL Queen Square Institute of Neurology, London, UK
| | - Helen Rice
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
- Dementia Research Centre, UCL Queen Square Institute of Neurology, London, UK
- UCL Queen Square Institute of Neurology, UK Dementia Research Institute at UCL, London, UK
| | - Tammaryn Lashley
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Nick C Fox
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
- Dementia Research Centre, UCL Queen Square Institute of Neurology, London, UK
- UCL Queen Square Institute of Neurology, UK Dementia Research Institute at UCL, London, UK
| | - Natalie S Ryan
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
- Dementia Research Centre, UCL Queen Square Institute of Neurology, London, UK
- UCL Queen Square Institute of Neurology, UK Dementia Research Institute at UCL, London, UK
| | - Selina Wray
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
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Shen T, Shi J, Zhao X, Fu L, Wang N, Zheng X, Chen Y, Li M, Ma C, Liu P, Zhu D. Presenilin 1 Is a Therapeutic Target in Pulmonary Hypertension and Promotes Vascular Remodeling. Am J Respir Cell Mol Biol 2024; 70:468-481. [PMID: 38381098 DOI: 10.1165/rcmb.2022-0426oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 02/20/2024] [Indexed: 02/22/2024] Open
Abstract
Small muscular pulmonary artery remodeling is a dominant feature of pulmonary arterial hypertension (PAH). PSEN1 affects angiogenesis, cancer, and Alzheimer's disease. We aimed to determine the role of PSEN1 in the pathogenesis of vascular remodeling in pulmonary hypertension (PH). Hemodynamics and vascular remodeling in the Psen1-knockin and smooth muscle-specific Psen1-knockout mice were assessed. The functional partners of PSEN1 were predicted by bioinformatics analysis and biochemical experiments. The therapeutic effect of PH was evaluated by administration of the PSEN1-specific inhibitor ELN318463. We discovered that both the mRNA and protein levels of PSEN1 were increased over time in hypoxic rats, monocrotaline rats, and Su5416/hypoxia mice. Psen1 transgenic mice were highly susceptible to PH, whereas smooth muscle-specific Psen1-knockout mice were resistant to hypoxic PH. STRING analysis showed that Notch1/2/3, β-catenin, Cadherin-1, DNER (delta/notch-like epidermal growth factor-related receptor), TMP10, and ERBB4 appeared to be highly correlated with PSEN1. Immunoprecipitation confirmed that PSEN1 interacts with β-catenin and DNER, and these interactions were suppressed by the catalytic PSEN1 mutations D257A, D385A, and C410Y. PSEN1 was found to mediate the nuclear translocation of the Notch1 intracellular domains and activated RBP-Jκ. Octaarginine-coated liposome-mediated pharmacological inhibition of PSEN1 significantly prevented and reversed the pathological process in hypoxic and monocrotaline-induced PH. PSEN1 essentially drives the pathogenesis of PAH and interacted with the noncanonical Notch ligand DNER. PSEN1 can be used as a promising molecular target for treating PAH. PSEN1 inhibitor ELN318463 can prevent and reverse the progression of PH and can be developed as a potential anti-PAH drug.
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Affiliation(s)
- TingTing Shen
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - JiuCheng Shi
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - XiJuan Zhao
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - Li Fu
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - Na Wang
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - XiaoDong Zheng
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - YingLi Chen
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - MingHui Li
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - Cui Ma
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
| | - PiXu Liu
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, China
| | - DaLing Zhu
- Central Laboratory of Harbin Medical University-Daqing, College of Medical Laboratory Science and Technology, Harbin Medical University (Daqing), Daqing, China; and
- College of Pharmacy, Harbin Medical University, Harbin, China
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3
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Zoltowska KM, Das U, Lismont S, Enzlein T, Maesako M, Houser MCQ, Franco ML, Özcan B, Moreira DG, Karachentsev D, Becker A, Hopf C, Vilar M, Berezovska O, Mobley W, Chávez-Gutiérrez L. Alzheimer's disease linked Aβ42 exerts product feedback inhibition on γ-secretase impairing downstream cell signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.02.551596. [PMID: 37577527 PMCID: PMC10418207 DOI: 10.1101/2023.08.02.551596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Amyloid β (Aβ) peptides accumulating in the brain are proposed to trigger Alzheimer's disease (AD). However, molecular cascades underlying their toxicity are poorly defined. Here, we explored a novel hypothesis for Aβ42 toxicity that arises from its proven affinity for γ-secretases. We hypothesized that the reported increases in Aβ42, particularly in the endolysosomal compartment, promote the establishment of a product feedback inhibitory mechanism on γ-secretases, and thereby impair downstream signaling events. We show that human Aβ42 peptides, but neither murine Aβ42 nor human Aβ17-42 (p3), inhibit γ-secretases and trigger accumulation of unprocessed substrates in neurons, including C-terminal fragments (CTFs) of APP, p75 and pan-cadherin. Moreover, Aβ42 treatment dysregulated cellular -homeostasis, as shown by the induction of p75-dependent neuronal death in two distinct cellular systems. Our findings raise the possibility that pathological elevations in Aβ42 contribute to cellular toxicity via the γ-secretase inhibition, and provide a novel conceptual framework to address Aβ toxicity in the context of γ-secretase-dependent homeostatic signaling.
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Affiliation(s)
| | - Utpal Das
- Department of Neurosciences, University of California San Diego, La Jolla, CA, United States of America
| | - Sam Lismont
- VIB-KU Leuven Center for Brain & Disease Research, VIB, Leuven, Belgium
| | - Thomas Enzlein
- VIB-KU Leuven Center for Brain & Disease Research, VIB, Leuven, Belgium
- Center for Mass Spectrometry and Optical Spectroscopy (CeMOS), Mannheim University of Applied Sciences, Mannheim, Germany
| | - Masato Maesako
- Department of Neurology, Massachusetts General Hospital/Harvard Medical School, Charlestown, MA, United States of America
| | - Mei CQ Houser
- Department of Neurology, Massachusetts General Hospital/Harvard Medical School, Charlestown, MA, United States of America
| | - María Luisa Franco
- Molecular Basis of Neurodegeneration Unit, Institute of Biomedicine of València (IBV-CSIC), València, Spain
| | - Burcu Özcan
- VIB-KU Leuven Center for Brain & Disease Research, VIB, Leuven, Belgium
| | | | - Dmitry Karachentsev
- Department of Neurosciences, University of California San Diego, La Jolla, CA, United States of America
| | - Ann Becker
- Department of Neurosciences, University of California San Diego, La Jolla, CA, United States of America
| | - Carsten Hopf
- Center for Mass Spectrometry and Optical Spectroscopy (CeMOS), Mannheim University of Applied Sciences, Mannheim, Germany
- Medical Faculty, Heidelberg University, Heidelberg, Germany
- Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Marçal Vilar
- Molecular Basis of Neurodegeneration Unit, Institute of Biomedicine of València (IBV-CSIC), València, Spain
| | - Oksana Berezovska
- Department of Neurology, Massachusetts General Hospital/Harvard Medical School, Charlestown, MA, United States of America
| | - William Mobley
- Department of Neurosciences, University of California San Diego, La Jolla, CA, United States of America
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De Strooper B, Karran E. New precision medicine avenues to the prevention of Alzheimer's disease from insights into the structure and function of γ-secretases. EMBO J 2024; 43:887-903. [PMID: 38396302 PMCID: PMC10943082 DOI: 10.1038/s44318-024-00057-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 01/20/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Two phase-III clinical trials with anti-amyloid peptide antibodies have met their primary goal, i.e. slowing of Alzheimer's disease (AD) progression. However, antibody therapy may not be the optimal therapeutic modality for AD prevention, as we will discuss in the context of the earlier small molecules described as "γ-secretase modulators" (GSM). We review here the structure, function, and pathobiology of γ-secretases, with a focus on how mutations in presenilin genes result in early-onset AD. Significant progress has been made in generating compounds that act in a manner opposite to pathogenic presenilin mutations: they stabilize the proteinase-substrate complex, thereby increasing the processivity of substrate cleavage and altering the size spectrum of Aβ peptides produced. We propose the term "γ-secretase allosteric stabilizers" (GSAS) to distinguish these compounds from the rather heterogenous class of GSM. The GSAS represent, in theory, a precision medicine approach to the prevention of amyloid deposition, as they specifically target a discrete aspect in a complex cell biological signalling mechanism that initiates the pathological processes leading to Alzheimer's disease.
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Affiliation(s)
- Bart De Strooper
- Dementia Research Institute, Institute of Neurology, University College London, at the Francis Crick Institute, London, NW1 AT, UK.
- Laboratory for the Research of Neurodegenerative Diseases, VIB Center for Brain & Disease Research, and Leuven Brain Institute, KU Leuven, Leuven, 3000, Belgium.
| | - Eric Karran
- Cambridge Research Center, AbbVie, Inc., Cambridge, MA, USA
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5
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Koch M, Enzlein T, Chen S, Petit D, Lismont S, Zacharias M, Hopf C, Chávez‐Gutiérrez L. APP substrate ectodomain defines amyloid-β peptide length by restraining γ-secretase processivity and facilitating product release. EMBO J 2023; 42:e114372. [PMID: 37853914 PMCID: PMC10690472 DOI: 10.15252/embj.2023114372] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 09/19/2023] [Accepted: 09/25/2023] [Indexed: 10/20/2023] Open
Abstract
Sequential proteolysis of the amyloid precursor protein (APP) by γ-secretases generates amyloid-β (Aβ) peptides and defines the proportion of short-to-long Aβ peptides, which is tightly connected to Alzheimer's disease (AD) pathogenesis. Here, we study the mechanism that controls substrate processing by γ-secretases and Aβ peptide length. We found that polar interactions established by the APPC99 ectodomain (ECD), involving but not limited to its juxtamembrane region, restrain both the extent and degree of γ-secretases processive cleavage by destabilizing enzyme-substrate interactions. We show that increasing hydrophobicity, via mutation or ligand binding, at APPC99 -ECD attenuates substrate-driven product release and rescues the effects of Alzheimer's disease-associated pathogenic γ-secretase and APP variants on Aβ length. In addition, our study reveals that APPC99 -ECD facilitates the paradoxical production of longer Aβs caused by some γ-secretase inhibitors, which act as high-affinity competitors of the substrate. These findings assign a pivotal role to the substrate ECD in the sequential proteolysis by γ-secretases and suggest it as a sweet spot for the potential design of APP-targeting compounds selectively promoting its processing by these enzymes.
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Affiliation(s)
- Matthias Koch
- VIB/KU Leuven, VIB‐KU Leuven Center for Brain and Disease ResearchLeuvenBelgium
| | - Thomas Enzlein
- VIB/KU Leuven, VIB‐KU Leuven Center for Brain and Disease ResearchLeuvenBelgium
- Center for Mass Spectrometry and Optical Spectroscopy (CeMOS)Mannheim University of Applied SciencesMannheimGermany
| | - Shu‐Yu Chen
- Physics Department and Center of Functional Protein AssembliesTechnical University of MunichGarchingGermany
| | - Dieter Petit
- VIB/KU Leuven, VIB‐KU Leuven Center for Brain and Disease ResearchLeuvenBelgium
| | - Sam Lismont
- VIB/KU Leuven, VIB‐KU Leuven Center for Brain and Disease ResearchLeuvenBelgium
| | - Martin Zacharias
- Physics Department and Center of Functional Protein AssembliesTechnical University of MunichGarchingGermany
| | - Carsten Hopf
- Center for Mass Spectrometry and Optical Spectroscopy (CeMOS)Mannheim University of Applied SciencesMannheimGermany
- Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty MannheimHeidelberg UniversityMannheimGermany
- Medical FacultyHeidelberg UniversityHeidelbergGermany
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6
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Kepp KP, Robakis NK, Høilund-Carlsen PF, Sensi SL, Vissel B. The amyloid cascade hypothesis: an updated critical review. Brain 2023; 146:3969-3990. [PMID: 37183523 DOI: 10.1093/brain/awad159] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 04/20/2023] [Accepted: 04/23/2023] [Indexed: 05/16/2023] Open
Abstract
Results from recent clinical trials of antibodies that target amyloid-β (Aβ) for Alzheimer's disease have created excitement and have been heralded as corroboration of the amyloid cascade hypothesis. However, while Aβ may contribute to disease, genetic, clinical, imaging and biochemical data suggest a more complex aetiology. Here we review the history and weaknesses of the amyloid cascade hypothesis in view of the new evidence obtained from clinical trials of anti-amyloid antibodies. These trials indicate that the treatments have either no or uncertain clinical effect on cognition. Despite the importance of amyloid in the definition of Alzheimer's disease, we argue that the data point to Aβ playing a minor aetiological role. We also discuss data suggesting that the concerted activity of many pathogenic factors contribute to Alzheimer's disease and propose that evolving multi-factor disease models will better underpin the search for more effective strategies to treat the disease.
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Affiliation(s)
- Kasper P Kepp
- Section of Biophysical and Biomedicinal chemistry, DTU Chemistry, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Nikolaos K Robakis
- Icahn School of Medicine at Mount Sinai Medical Center, New York, NY 10029, USA
| | - Poul F Høilund-Carlsen
- Department of Nuclear Medicine, Odense University Hospital, 5000 Odense C, Denmark
- Department of Clinical Research, University of Southern Denmark, 5000 Odense C, Denmark
| | - Stefano L Sensi
- Center for Advanced Studies and Technology-CAST, and Institute for Advanced Biotechnology (ITAB), University G. d'Annunzio of Chieti-Pescara, Chieti, 66013, Italy
- Department of Neuroscience, Imaging, and Clinical Sciences, University G. d'Annunzio of Chieti-Pescara, Chieti, 66013, Italy
| | - Bryce Vissel
- St Vincent's Hospital Centre for Applied Medical Research, St Vincent's Hospital, Sydney, 2010, Australia
- School of Clinical Medicine, UNSW Medicine and Health, St Vincent's Healthcare Clinical Campus, Faculty of Medicine and Health, Sydney, NSW 2052, Australia
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7
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Kurth V, Ogorek I, Münch C, Lopez-Rios J, Ousson S, Lehmann S, Nieweg K, Roebroek AJM, Pietrzik CU, Beher D, Weggen S. Pathogenic Aβ production by heterozygous PSEN1 mutations is intrinsic to the mutant protein and not mediated by conformational hindrance of wild-type PSEN1. J Biol Chem 2023; 299:104997. [PMID: 37394008 PMCID: PMC10413157 DOI: 10.1016/j.jbc.2023.104997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 05/30/2023] [Accepted: 06/07/2023] [Indexed: 07/04/2023] Open
Abstract
Presenilin-1 (PSEN1) is the catalytic subunit of the intramembrane protease γ-secretase and undergoes endoproteolysis during its maturation. Heterozygous mutations in the PSEN1 gene cause early-onset familial Alzheimer's disease (eFAD) and increase the proportion of longer aggregation-prone amyloid-β peptides (Aβ42 and/or Aβ43). Previous studies had suggested that PSEN1 mutants might act in a dominant-negative fashion by functional impediment of wild-type PSEN1, but the exact mechanism by which PSEN1 mutants promote pathogenic Aβ production remains controversial. Using dual recombinase-mediated cassette exchange (dRMCE), here we generated a panel of isogenic embryonic and neural stem cell lines with heterozygous, endogenous expression of PSEN1 mutations. When catalytically inactive PSEN1 was expressed alongside the wild-type protein, we found the mutant accumulated as a full-length protein, indicating that endoproteolytic cleavage occurred strictly as an intramolecular event. Heterozygous expression of eFAD-causing PSEN1 mutants increased the Aβ42/Aβ40 ratio. In contrast, catalytically inactive PSEN1 mutants were still incorporated into the γ-secretase complex but failed to change the Aβ42/Aβ40 ratio. Finally, interaction and enzyme activity assays demonstrated the binding of mutant PSEN1 to other γ-secretase subunits, but no interaction between mutant and wild-type PSEN1 was observed. These results establish that pathogenic Aβ production is an intrinsic property of PSEN1 mutants and strongly argue against a dominant-negative effect in which PSEN1 mutants would compromise the catalytic activity of wild-type PSEN1 through conformational effects.
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Affiliation(s)
- Vanessa Kurth
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany
| | - Isabella Ogorek
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany; Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Carolina Münch
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany
| | - Javier Lopez-Rios
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide-Junta de Andalucia, Sevilla, Spain
| | | | - Sandra Lehmann
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany
| | - Katja Nieweg
- Institute of Pharmacology and Clinical Pharmacy, Philipps-University, Marburg, Germany
| | | | - Claus U Pietrzik
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | | | - Sascha Weggen
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany.
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8
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Tambini MD, Yin T, Yesiltepe M, Breuillaud L, Zehntner SP, d'Abramo C, Giliberto L, D'Adamio L. Aβ43 levels determine the onset of pathological amyloid deposition. J Biol Chem 2023; 299:104868. [PMID: 37257821 PMCID: PMC10404620 DOI: 10.1016/j.jbc.2023.104868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/18/2023] [Accepted: 05/22/2023] [Indexed: 06/02/2023] Open
Abstract
About 2% of Alzheimer's disease (AD) cases have early onset (FAD) and are caused by mutations in either Presenilins (PSEN1/2) or amyloid-β precursor protein (APP). PSEN1/2 catalyze production of Aβ peptides of different length from APP. Aβ peptides are the major components of amyloid plaques, a pathological lesion that characterizes AD. Analysis of mechanisms by which PSEN1/2 and APP mutations affect Aβ peptide compositions lead to the implication of the absolute or relative increase in Aβ42 in amyloid-β plaques formation. Here, to elucidate the formation of pathogenic Aβ cocktails leading to amyloid pathology, we utilized FAD rat knock-in models carrying the Swedish APP (Apps allele) and the PSEN1 L435F (Psen1LF allele) mutations. To accommodate the differences in the pathogenicity of rodent and human Aβ, these rat models are genetically engineered to express human Aβ species as both the Swedish mutant allele and the WT rat allele (called Apph) have been humanized in the Aβ-coding region. Analysis of the eight possible FAD mutant permutations indicates that the CNS levels of Aβ43, rather than absolute or relative increases in Aβ42, determine the onset of pathological amyloid deposition in FAD knock-in rats. Notably, Aβ43 was found in amyloid plaques in late onset AD and mild cognitive impairment cases, suggesting that the mechanisms initiating amyloid pathology in FAD knock-in rat reflect disease mechanisms driving amyloid pathology in late onset AD. This study helps clarifying the molecular determinants initiating amyloid pathology and supports therapeutic interventions targeting Aβ43 in AD.
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Affiliation(s)
- Marc D Tambini
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Tao Yin
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Metin Yesiltepe
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | | | | | - Cristina d'Abramo
- Litwin-Zucker Center for the Study of Alzheimer's Disease and Memory Disorders, Feinstein Institutes for Medical Research, Institute of Molecular Medicine, Northwell Health System, Manhasset, New York, USA
| | - Luca Giliberto
- Litwin-Zucker Center for the Study of Alzheimer's Disease and Memory Disorders, Feinstein Institutes for Medical Research, Institute of Molecular Medicine, Northwell Health System, Manhasset, New York, USA; Institute of Neurology and Neurosurgery, Northwell Health System, Manhasset, New York, USA
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA.
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9
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Schmidt FC, Fitz K, Feilen LP, Okochi M, Steiner H, Langosch D. Different transmembrane domains determine the specificity and efficiency of the cleavage activity of the γ-secretase subunit presenilin. J Biol Chem 2023; 299:104626. [PMID: 36944398 PMCID: PMC10164903 DOI: 10.1016/j.jbc.2023.104626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 03/07/2023] [Accepted: 03/11/2023] [Indexed: 03/23/2023] Open
Abstract
The γ-secretase complex catalyzes the intramembrane cleavage of C99, a carboxy-terminal fragment of the amyloid precursor protein. Two paralogs of its catalytic subunit presenilin (PS1 and PS2) are expressed which are autocatalytically cleaved into an N-terminal and a C-terminal fragment during maturation of γ-secretase. In this study, we compared the efficiency and specificity of C99 cleavage by PS1- and PS2-containing γ-secretases. Mass spectrometric analysis of cleavage products obtained in cell-free and cell-based assays revealed that the previously described lower amyloid-β (Aβ)38 generation by PS2 is accompanied by a reciprocal increase in Aβ37 production. We further found PS1 and PS2 to show different preferences in the choice of the initial cleavage site of C99. However, the differences in Aβ38 and Aβ37 generation appear to mainly result from altered subsequent stepwise cleavage of Aβ peptides. Apart from these differences in cleavage specificity, we confirmed a lower efficiency of initial C99 cleavage by PS2 using a detergent-solubilized γ-secretase system. By investigating chimeric PS1/2 molecules, we show that the membrane-embedded, nonconserved residues of the N-terminal fragment mainly account for the differential cleavage efficiency and specificity of both presenilins. At the level of individual transmembrane domains (TMDs), TMD3 was identified as a major modulator of initial cleavage site specificity. The efficiency of endoproteolysis strongly depends on nonconserved TMD6 residues at the interface to TMD2, i.e., at a putative gate of substrate entry. Taken together, our results highlight the role of individual presenilin TMDs in the cleavage of C99 and the generation of Aβ peptides.
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Affiliation(s)
- Fabian C Schmidt
- Biopolymer Chemistry, Technical University of Munich, Freising, Germany
| | - Katja Fitz
- Biopolymer Chemistry, Technical University of Munich, Freising, Germany
| | - Lukas P Feilen
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Masayasu Okochi
- Neuropsychiatry, Division of Internal Medicine, Department of Integrated Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Harald Steiner
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany; Division of Metabolic Biochemistry, Faculty of Medicine, Biomedical Center (BMC), Ludwig-Maximilians-University, Munich, Germany
| | - Dieter Langosch
- Biopolymer Chemistry, Technical University of Munich, Freising, Germany.
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10
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Cooperation of N- and C-terminal substrate transmembrane domain segments in intramembrane proteolysis by γ-secretase. Commun Biol 2023; 6:177. [PMID: 36792683 PMCID: PMC9931712 DOI: 10.1038/s42003-023-04470-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 01/11/2023] [Indexed: 02/17/2023] Open
Abstract
Intramembrane proteases play a pivotal role in biology and medicine, but how these proteases decode cleavability of a substrate transmembrane (TM) domain remains unclear. Here, we study the role of conformational flexibility of a TM domain, as determined by deuterium/hydrogen exchange, on substrate cleavability by γ-secretase in vitro and in cellulo. By comparing hybrid TMDs based on the natural amyloid precursor protein TM domain and an artificial poly-Leu non-substrate, we find that substrate cleavage requires conformational flexibility within the N-terminal half of the TMD helix (TM-N). Robust cleavability also requires the C-terminal TM sequence (TM-C) containing substrate cleavage sites. Since flexibility of TM-C does not correlate with cleavage efficiency, the role of the TM-C may be defined mainly by its ability to form a cleavage-competent state near the active site, together with parts of presenilin, the enzymatic component of γ-secretase. In sum, cleavability of a γ-secretase substrate appears to depend on cooperating TM domain segments, which deepens our mechanistic understanding of intramembrane proteolysis.
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11
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Do HN, Devkota S, Bhattarai A, Wolfe MS, Miao Y. Effects of presenilin-1 familial Alzheimer's disease mutations on γ-secretase activation for cleavage of amyloid precursor protein. Commun Biol 2023; 6:174. [PMID: 36788318 PMCID: PMC9929099 DOI: 10.1038/s42003-023-04539-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 01/30/2023] [Indexed: 02/16/2023] Open
Abstract
Presenilin-1 (PS1) is the catalytic subunit of γ-secretase which cleaves within the transmembrane domain of over 150 peptide substrates. Dominant missense mutations in PS1 cause early-onset familial Alzheimer's disease (FAD); however, the exact pathogenic mechanism remains unknown. Here we combined Gaussian accelerated molecular dynamics (GaMD) simulations and biochemical experiments to determine the effects of six representative PS1 FAD mutations (P117L, I143T, L166P, G384A, L435F, and L286V) on the enzyme-substrate interactions between γ-secretase and amyloid precursor protein (APP). Biochemical experiments showed that all six PS1 FAD mutations rendered γ-secretase less active for the endoproteolytic (ε) cleavage of APP. Distinct low-energy conformational states were identified from the free energy profiles of wildtype and PS1 FAD-mutant γ-secretase. The P117L and L286V FAD mutants could still sample the "Active" state for substrate cleavage, but with noticeably reduced conformational space compared with the wildtype. The other mutants hardly visited the "Active" state. The PS1 FAD mutants were found to reduce γ-secretase proteolytic activity by hindering APP residue L49 from proper orientation in the active site and/or disrupting the distance between the catalytic aspartates. Therefore, our findings provide mechanistic insights into how PS1 FAD mutations affect structural dynamics and enzyme-substrate interactions of γ-secretase and APP.
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Affiliation(s)
- Hung N. Do
- grid.266515.30000 0001 2106 0692Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047 USA
| | - Sujan Devkota
- grid.266515.30000 0001 2106 0692Department of Medicinal Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS 66047 USA
| | - Apurba Bhattarai
- grid.266515.30000 0001 2106 0692Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66047 USA
| | - Michael S. Wolfe
- grid.266515.30000 0001 2106 0692Department of Medicinal Chemistry, School of Pharmacy, University of Kansas, Lawrence, KS 66047 USA
| | - Yinglong Miao
- Center for Computational Biology and Department of Molecular Biosciences, University of Kansas, Lawrence, KS, 66047, USA.
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12
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Lardelli M. An Alternative View of Familial Alzheimer's Disease Genetics. J Alzheimers Dis 2023; 96:13-39. [PMID: 37718800 DOI: 10.3233/jad-230313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
Probabilistic and parsimony-based arguments regarding available genetics data are used to propose that Hardy and Higgin's amyloid cascade hypothesis is valid but is commonly interpreted too narrowly to support, incorrectly, the primacy of the amyloid-β peptide (Aβ) in driving Alzheimer's disease pathogenesis. Instead, increased activity of the βCTF (C99) fragment of AβPP is the critical pathogenic determinant altered by mutations in the APP gene. This model is consistent with the regulation of APP mRNA translation via its 5' iron responsive element. Similar arguments support that the pathological effects of familial Alzheimer's disease mutations in the genes PSEN1 and PSEN2 are not exerted directly via changes in AβPP cleavage to produce different ratios of Aβ length. Rather, these mutations likely act through effects on presenilin holoprotein conformation and function, and possibly the formation and stability of multimers of presenilin holoprotein and/or of the γ-secretase complex. All fAD mutations in APP, PSEN1, and PSEN2 likely find unity of pathological mechanism in their actions on endolysosomal acidification and mitochondrial function, with detrimental effects on iron homeostasis and promotion of "pseudo-hypoxia" being of central importance. Aβ production is enhanced and distorted by oxidative stress and accumulates due to decreased lysosomal function. It may act as a disease-associated molecular pattern enhancing oxidative stress-driven neuroinflammation during the cognitive phase of the disease.
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Affiliation(s)
- Michael Lardelli
- Alzheimer's Disease Genetics Laboratory, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
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13
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Kobro-Flatmoen A, Hormann TM, Gouras G. Intracellular Amyloid-β in the Normal Rat Brain and Human Subjects and Its relevance for Alzheimer's Disease. J Alzheimers Dis 2023; 95:719-733. [PMID: 37574734 PMCID: PMC10578257 DOI: 10.3233/jad-230349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2023] [Indexed: 08/15/2023]
Abstract
BACKGROUND Amyloid-β (Aβ) is a normal product of neuronal activity, including that of the aggregation-prone Aβ42 variant that is thought to cause Alzheimer's disease (AD). Much knowledge about AD comes from studies of transgenic rodents expressing mutated human amyloid-β protein precursor (AβPP) to increase Aβ production or the Aβ42/40 ratio. Yet, little is known about the normal expression of Aβ42 in rodent brains. OBJECTIVE To characterize the brain-wide expression of Aβ42 throughout the life span of outbred Wistar rats, and to relate these findings to brains of human subjects without neurological disease. METHODS Aβ42 immunolabeling of 12 Wistar rat brains (3-18 months of age) and brain sections from six human subjects aged 20-88 years. RESULTS In healthy Wistar rats, we find intracellular Aβ42 (iAβ42) in neurons throughout the brain at all ages, but levels vary greatly between brain regions. The highest levels are in neurons of entorhinal cortex layer II, alongside hippocampal neurons at the CA1/subiculum border. Concerning entorhinal cortex layer II, we find similarly high levels of iAβ42 in the human subjects. CONCLUSION Expression of iAβ42 in healthy Wistar rats predominates in the same structures where iAβ accumulates and Aβ plaques initially form in the much used, Wistar based McGill-R-Thy1-APP rat model for AD. The difference between wild-type Wistar rats and these AD model rats, with respect to Aβ42, is therefore quantitative rather that qualitative. This, taken together with our human results, indicate that the McGill rat model in fact models the underlying wild-type neuronal population-specific vulnerability to Aβ42 accumulation.
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Affiliation(s)
- Asgeir Kobro-Flatmoen
- Kavli Institute for Systems Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway
- K.G. Jebsen Centre for Alzheimer’s Disease, NTNU, Trondheim, Norway
| | - Thea Meier Hormann
- Kavli Institute for Systems Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway
| | - Gunnar Gouras
- Department of Experimental Medical Science, Experimental Dementia Research Unit, Lund University, Lund, Sweden
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14
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Petit D, Hitzenberger M, Koch M, Lismont S, Zoltowska KM, Enzlein T, Hopf C, Zacharias M, Chávez-Gutiérrez L. Enzyme-substrate interface targeting by imidazole-based γ-secretase modulators activates γ-secretase and stabilizes its interaction with APP. EMBO J 2022; 41:e111084. [PMID: 36121025 DOI: 10.15252/embj.2022111084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 08/11/2022] [Accepted: 08/22/2022] [Indexed: 11/09/2022] Open
Abstract
Alzheimer's disease (AD) pathogenesis has been linked to the accumulation of longer, aggregation-prone amyloid β (Aβ) peptides in the brain. Γ-secretases generate Aβ peptides from the amyloid precursor protein (APP). Γ-secretase modulators (GSMs) promote the generation of shorter, less-amyloidogenic Aβs and have therapeutic potential. However, poorly defined drug-target interactions and mechanisms of action have hampered their therapeutic development. Here, we investigate the interactions between the imidazole-based GSM and its target γ-secretase-APP using experimental and in silico approaches. We map the GSM binding site to the enzyme-substrate interface, define a drug-binding mode that is consistent with functional and structural data, and provide molecular insights into the underlying mechanisms of action. In this respect, our analyses show that occupancy of a γ-secretase (sub)pocket, mediating binding of the modulator's imidazole moiety, is sufficient to trigger allosteric rearrangements in γ-secretase as well as stabilize enzyme-substrate interactions. Together, these findings may facilitate the rational design of new modulators of γ-secretase with improved pharmacological properties.
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Affiliation(s)
- Dieter Petit
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
| | - Manuel Hitzenberger
- Center for Functional Protein Assemblies, Theoretical Biophysics (T38), Technical University of Munich, Garching, Germany
| | - Matthias Koch
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
| | - Sam Lismont
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
| | - Katarzyna Marta Zoltowska
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
| | - Thomas Enzlein
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium.,Center for Mass Spectrometry and Optical Spectroscopy (CeMOS), Mannheim University of Applied Sciences, Mannheim, Germany
| | - Carsten Hopf
- Center for Mass Spectrometry and Optical Spectroscopy (CeMOS), Mannheim University of Applied Sciences, Mannheim, Germany.,Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - Martin Zacharias
- Center for Functional Protein Assemblies, Theoretical Biophysics (T38), Technical University of Munich, Garching, Germany
| | - Lucía Chávez-Gutiérrez
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium.,Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
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15
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Petit D, Fernández SG, Zoltowska KM, Enzlein T, Ryan NS, O'Connor A, Szaruga M, Hill E, Vandenberghe R, Fox NC, Chávez-Gutiérrez L. Aβ profiles generated by Alzheimer's disease causing PSEN1 variants determine the pathogenicity of the mutation and predict age at disease onset. Mol Psychiatry 2022; 27:2821-2832. [PMID: 35365805 PMCID: PMC9156411 DOI: 10.1038/s41380-022-01518-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 02/23/2022] [Accepted: 03/03/2022] [Indexed: 02/05/2023]
Abstract
Familial Alzheimer's disease (FAD), caused by mutations in Presenilin (PSEN1/2) and Amyloid Precursor Protein (APP) genes, is associated with an early age at onset (AAO) of symptoms. AAO is relatively consistent within families and between carriers of the same mutations, but differs markedly between individuals carrying different mutations. Gaining a mechanistic understanding of why certain mutations manifest several decades earlier than others is extremely important in elucidating the foundations of pathogenesis and AAO. Pathogenic mutations affect the protease (PSEN/γ-secretase) and the substrate (APP) that generate amyloid β (Aβ) peptides. Altered Aβ metabolism has long been associated with AD pathogenesis, with absolute or relative increases in Aβ42 levels most commonly implicated in the disease development. However, analyses addressing the relationships between these Aβ42 increments and AAO are inconsistent. Here, we investigated this central aspect of AD pathophysiology via comprehensive analysis of 25 FAD-linked Aβ profiles. Hypothesis- and data-driven approaches demonstrate linear correlations between mutation-driven alterations in Aβ profiles and AAO. In addition, our studies show that the Aβ (37 + 38 + 40) / (42 + 43) ratio offers predictive value in the assessment of 'unclear' PSEN1 variants. Of note, the analysis of PSEN1 variants presenting additionally with spastic paraparesis, indicates that a different mechanism underlies the aetiology of this distinct clinical phenotype. This study thus delivers valuable assays for fundamental, clinical and genetic research as well as supports therapeutic interventions aimed at shifting Aβ profiles towards shorter Aβ peptides.
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Affiliation(s)
- Dieter Petit
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Sara Gutiérrez Fernández
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Katarzyna Marta Zoltowska
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Thomas Enzlein
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
- Center for Mass Spectrometry and Optical Spectroscopy (CeMOS), Mannheim University of Applied Sciences, Paul-Wittsack Str. 10, 68163, Mannheim, Germany
| | - Natalie S Ryan
- UK Dementia Research Institute at UCL, Queen Square, WC1N 3BG, London, UK
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG, London, UK
| | - Antoinette O'Connor
- UK Dementia Research Institute at UCL, Queen Square, WC1N 3BG, London, UK
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG, London, UK
| | - Maria Szaruga
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Elizabeth Hill
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium
| | - Rik Vandenberghe
- Laboratory for Cognitive Neurology, Department of Neurosciences, KU Leuven, Herestraat 49 box 1027, 3000, Leuven, Belgium
- Neurology Department, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Nick C Fox
- UK Dementia Research Institute at UCL, Queen Square, WC1N 3BG, London, UK
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG, London, UK
| | - Lucía Chávez-Gutiérrez
- VIB-KU Leuven Center for Brain & Disease Research, Herestraat 49 box 602, 3000, Leuven, Belgium.
- Department of Neurosciences, Leuven Brain Institute, KU Leuven, Herestraat 49 box 602, 3000, Leuven, Belgium.
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16
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Golde TE. Alzheimer’s disease – the journey of a healthy brain into organ failure. Mol Neurodegener 2022; 17:18. [PMID: 35248124 PMCID: PMC8898417 DOI: 10.1186/s13024-022-00523-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/17/2022] [Indexed: 12/19/2022] Open
Abstract
As the most common dementia, Alzheimer’s disease (AD) exacts an immense personal, societal, and economic toll. AD was first described at the neuropathological level in the early 1900s. Today, we have mechanistic insight into select aspects of AD pathogenesis and have the ability to clinically detect and diagnose AD and underlying AD pathologies in living patients. These insights demonstrate that AD is a complex, insidious, degenerative proteinopathy triggered by Aβ aggregate formation. Over time Aβ pathology drives neurofibrillary tangle (NFT) pathology, dysfunction of virtually all cell types in the brain, and ultimately, overt neurodegeneration. Yet, large gaps in our knowledge of AD pathophysiology and huge unmet medical need remain. Though we largely conceptualize AD as a disease of aging, heritable and non-heritable factors impact brain physiology, either continuously or at specific time points during the lifespan, and thereby alter risk for devolvement of AD. Herein, I describe the lifelong journey of a healthy brain from birth to death with AD, while acknowledging the many knowledge gaps that remain regarding our understanding of AD pathogenesis. To ensure the current lexicon surrounding AD changes from inevitable, incurable, and poorly manageable to a lexicon of preventable, curable, and manageable we must address these knowledge gaps, develop therapies that have a bigger impact on clinical symptoms or progression of disease and use these interventions at the appropriate stage of disease.
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17
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Golde TE. Disease-Modifying Therapies for Alzheimer's Disease: More Questions than Answers. Neurotherapeutics 2022; 19:209-227. [PMID: 35229269 PMCID: PMC8885119 DOI: 10.1007/s13311-022-01201-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2022] [Indexed: 12/17/2022] Open
Abstract
Scientific advances over the last four decades have steadily infused the Alzheimer's disease (AD) field with great optimism that therapies targeting Aβ, amyloid, tau, and innate immune activation states in the brain would provide disease modification. Unfortunately, this optimistic scenario has not yet played out. Though a recent approval of the anti-Aβ aggregate binding antibody, Aduhelm (aducanumab), as a "disease-modifying therapy for AD" is viewed by some as a breakthrough, many remain unconvinced by the data underlying this approval. Collectively, we have not succeeded in changing AD from a largely untreatable, inevitable, and incurable disease to a treatable, preventable, and curable one. Here, I will review the major foci of the AD "disease-modifying" therapeutic pipeline and some of the "open questions" that remain in terms of these therapeutic approaches. I will conclude the review by discussing how we, as a field, might adjust our approach, learning from our past failures to ensure future success.
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Affiliation(s)
- Todd E Golde
- Departments of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, Evelyn F. and William L. McKnight Brain Institute, Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, USA.
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18
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Rahman MS, Uddin MS, Rahman MA, Samsuzzaman M, Behl T, Hafeez A, Perveen A, Barreto GE, Ashraf GM. Exploring the Role of Monoamine Oxidase Activity in Aging and Alzheimer's Disease. Curr Pharm Des 2021; 27:4017-4029. [PMID: 34126892 DOI: 10.2174/1381612827666210612051713] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 04/06/2021] [Indexed: 11/22/2022]
Abstract
Monoamine oxidases (MAOs) are a family of flavin adenine dinucleotide-dependent enzymes that exert a crucial role in the metabolism of neurotransmitters of the central nervous system. The impaired function of MAOs is associated with copious brain diseases. The alteration of monoamine metabolism is a characteristics feature of aging. MAO plays a crucial role in the pathogenesis of Alzheimer's disease (AD) - a progressive neurodegenerative disorder associated with an excessive accumulation of amyloid-beta (Aβ) peptide and neurofibrillary tangles (NFTs). Activated MAO has played a critical role in the development of amyloid plaques from Aβ, as well as the formation of the NFTs. In the brain, MAO mediated metabolism of monoamines is the foremost source of reactive oxygen species formation. The elevated level of MAO-B expression in astroglia has been reported in the AD brains adjacent to amyloid plaques. Increased MAO-B activity in the cortical and hippocampal regions is associated with AD. This review describes the pathogenic mechanism of MAOs in aging as well as the development and propagation of Alzheimer's pathology.
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Affiliation(s)
- Md Sohanur Rahman
- Department of Biochemistry and Molecular Biology, Trust University, Ruiya, Nobogram Road, Barishal 8200, Bangladesh
| | - Md Sahab Uddin
- Department of Pharmacy, Southeast University, Dhaka, Bangladesh
| | - Md Ataur Rahman
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology, Seoul. Korea
| | - Md Samsuzzaman
- Department of Food and Life Science, Pukyong National University, Busan 48513. Korea
| | - Tapan Behl
- Glocal School of Pharmacy, Glocal University, Saharanpur, India
| | - Abdul Hafeez
- Glocal School of Pharmacy, Glocal University, Saharanpur, India
| | - Asma Perveen
- Glocal School of Life Sciences, Glocal University, Saharanpur, India
| | - George E Barreto
- Department of Biological Sciences, University of Limerick, Limerick. Ireland
| | - Ghulam Md Ashraf
- Pre-Clinical Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah. Saudi Arabia
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19
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Ruiz-Riquelme A, Mao A, Barghash MM, Lau HHC, Stuart E, Kovacs GG, Nilsson KPR, Fraser PE, Schmitt-Ulms G, Watts JC. Aβ43 aggregates exhibit enhanced prion-like seeding activity in mice. Acta Neuropathol Commun 2021; 9:83. [PMID: 33971978 PMCID: PMC8112054 DOI: 10.1186/s40478-021-01187-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 04/24/2021] [Indexed: 02/07/2023] Open
Abstract
When injected into genetically modified mice, aggregates of the amyloid-β (Aβ) peptide from the brains of Alzheimer’s disease (AD) patients or transgenic AD mouse models seed cerebral Aβ deposition in a prion-like fashion. Within the brain, Aβ exists as a pool of distinct C-terminal variants with lengths ranging from 37 to 43 amino acids, yet the relative contribution of individual C-terminal Aβ variants to the seeding behavior of Aβ aggregates remains unknown. Here, we have investigated the relative seeding activities of Aβ aggregates composed exclusively of recombinant Aβ38, Aβ40, Aβ42, or Aβ43. Cerebral Aβ42 levels were not increased in AppNL−F knock-in mice injected with Aβ38 or Aβ40 aggregates and were only increased in a subset of mice injected with Aβ42 aggregates. In contrast, significant accumulation of Aβ42 was observed in the brains of all mice inoculated with Aβ43 aggregates, and the extent of Aβ42 induction was comparable to that in mice injected with brain-derived Aβ seeds. Mice inoculated with Aβ43 aggregates exhibited a distinct pattern of cerebral Aβ pathology compared to mice injected with brain-derived Aβ aggregates, suggesting that recombinant Aβ43 may polymerize into a unique strain. Our results indicate that aggregates containing longer Aβ C-terminal variants are more potent inducers of cerebral Aβ deposition and highlight the potential role of Aβ43 seeds as a crucial factor in the initial stages of Aβ pathology in AD.
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20
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Devkota S, Williams TD, Wolfe MS. Familial Alzheimer's disease mutations in amyloid protein precursor alter proteolysis by γ-secretase to increase amyloid β-peptides of ≥45 residues. J Biol Chem 2021; 296:100281. [PMID: 33450230 PMCID: PMC7948801 DOI: 10.1016/j.jbc.2021.100281] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/28/2020] [Accepted: 01/08/2021] [Indexed: 02/04/2023] Open
Abstract
Production of amyloid β-protein (Aβ) is carried out by the membrane-embedded γ-secretase complex. Mutations in the transmembrane domain of amyloid β-protein precursor (APP) associated with early-onset familial Alzheimer's disease (FAD) can alter the ratio of aggregation-prone 42-residue Aβ (Aβ42) to 40-residue Aβ (Aβ40). However, APP substrate is proteolyzed processively by γ-secretase along two pathways: Aβ49→Aβ46→Aβ43→Aβ40 and Aβ48→Aβ45→Aβ42→Aβ38. Effects of FAD mutations on each proteolytic step are unknown, largely due to difficulties in detecting and quantifying longer Aβ peptides. To address this, we carried out systematic and quantitative analyses of all tri- and tetrapeptide coproducts from proteolysis of wild-type and 14 FAD-mutant APP substrates by purified γ-secretase. These small peptides, including FAD-mutant forms, were detected by tandem mass spectrometry and quantified by establishing concentration curves for each of 32 standards. APP intracellular domain (AICD) coproducts were quantified by immunoblot, and the ratio of AICD products corresponding to Aβ48 and Aβ49 was determined by mass spectrometry. Levels of individual Aβ peptides were determined by subtracting levels of peptide coproducts associated with degradation from those associated with production. This method was validated for Aβ40 and Aβ42 by specific ELISAs and production of equimolar levels of Aβ and AICD. Not all mutant substrates led to increased Aβ42/40. However, all 14 disease-causing mutations led to inefficient processing of longer forms of Aβ ≥ 45 residues. In addition, the effects of certain mutations provided insight into the mechanism of processive proteolysis: intermediate Aβ peptides apparently remain bound for subsequent trimming and are not released and reassociated.
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Affiliation(s)
- Sujan Devkota
- Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas, USA
| | - Todd D Williams
- Mass Spectrometry Laboratory, University of Kansas, Lawrence, Kansas, USA
| | - Michael S Wolfe
- Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas, USA.
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21
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A computer-simulated mechanism of familial Alzheimer’s disease: Mutations enhance thermal dynamics and favor looser substrate-binding to γ-secretase. J Struct Biol 2020; 212:107648. [DOI: 10.1016/j.jsb.2020.107648] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/22/2020] [Accepted: 10/09/2020] [Indexed: 11/22/2022]
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22
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Oakley DH, Chung M, Klickstein N, Commins C, Hyman BT, Frosch MP. The Alzheimer Disease-Causing Presenilin-1 L435F Mutation Causes Increased Production of Soluble Aβ43 Species in Patient-Derived iPSC-Neurons, Closely Mimicking Matched Patient Brain Tissue. J Neuropathol Exp Neurol 2020; 79:592-604. [PMID: 32388561 DOI: 10.1093/jnen/nlaa025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/13/2020] [Accepted: 03/19/2020] [Indexed: 11/14/2022] Open
Abstract
Familial Alzheimer disease-causing mutations in Presenilin 1 (PSEN1) are generally thought to shift the processing of APP toward longer, more amyloidogenic Aβ fragments. However, certain PSEN1 mutations cause severe reduction in gamma secretase function when expressed in the homozygous state, thus challenging the amyloid hypothesis. We sought to evaluate the effects of one such mutation, PSEN1 L435F, in more physiologic conditions and genetic contexts by using human induced pluripotent stem cell (iPSC)-derived neurons from an individual with familial AD (fAD) linked to the PSEN1 L435F mutation, and compared the biochemical phenotype of the iPS-derived neurons with brain tissue obtained at autopsy from the same patient. Our results demonstrate that in the endogenous heterozygous state, the PSEN1 L435F mutation causes a large increase in soluble Aβ43 but does not change the overall levels of soluble Aβ40 or Aβ42 when compared with control iPSC-neurons. Increased pathologically phosphorylated tau species were also observed in PSEN1-mutant iPSC-neurons. Concordant changes in Aβ species were present in autopsy brain tissue from the same patient. Finally, the feasibility of using Aβ43 immunohistochemistry of brain tissue to identify fAD cases was evaluated in a limited autopsy case series with the finding that strong Aβ43 staining occurred only in fAD cases.
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Affiliation(s)
- Derek H Oakley
- From the Harvard Medical School, Boston, Massachusetts.,Massachusetts General Hospital Department of Pathology, Boston, Massachusetts.,C.S. Kubik Laboratory for Neuropathology, Boston, Massachusetts.,Massachusetts Alzheimer's Disease Research Center, Boston, Massachusetts
| | - Mirra Chung
- From the Harvard Medical School, Boston, Massachusetts.,Massachusetts General Hospital Department of Neurology, Boston, Massachusetts
| | - Naomi Klickstein
- From the Harvard Medical School, Boston, Massachusetts.,Massachusetts General Hospital Department of Neurology, Boston, Massachusetts
| | - Caitlin Commins
- From the Harvard Medical School, Boston, Massachusetts.,Massachusetts General Hospital Department of Neurology, Boston, Massachusetts
| | - Bradley T Hyman
- From the Harvard Medical School, Boston, Massachusetts.,Massachusetts General Hospital Department of Neurology, Boston, Massachusetts.,Massachusetts Alzheimer's Disease Research Center, Boston, Massachusetts
| | - Matthew P Frosch
- From the Harvard Medical School, Boston, Massachusetts.,Massachusetts General Hospital Department of Neurology, Boston, Massachusetts.,Massachusetts General Hospital Department of Pathology, Boston, Massachusetts.,C.S. Kubik Laboratory for Neuropathology, Boston, Massachusetts.,Massachusetts Alzheimer's Disease Research Center, Boston, Massachusetts
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23
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Perrone F, Bjerke M, Hens E, Sieben A, Timmers M, De Roeck A, Vandenberghe R, Sleegers K, Martin JJ, De Deyn PP, Engelborghs S, van der Zee J, Van Broeckhoven C, Cacace R. Amyloid-β 1-43 cerebrospinal fluid levels and the interpretation of APP, PSEN1 and PSEN2 mutations. ALZHEIMERS RESEARCH & THERAPY 2020; 12:108. [PMID: 32917274 PMCID: PMC7488767 DOI: 10.1186/s13195-020-00676-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 09/01/2020] [Indexed: 01/01/2023]
Abstract
Background Alzheimer’s disease (AD) mutations in amyloid precursor protein (APP) and presenilins (PSENs) could potentially lead to the production of longer amyloidogenic Aβ peptides. Amongst these, Aβ1–43 is more prone to aggregation and has higher toxic properties than the long-known Aβ1–42. However, a direct effect on Aβ1–43 in biomaterials of individuals carrying genetic mutations in the known AD genes is yet to be determined. Methods N = 1431 AD patients (n = 280 early-onset (EO) and n = 1151 late-onset (LO) AD) and 809 control individuals were genetically screened for APP and PSENs. For the first time, Aβ1–43 levels were analysed in cerebrospinal fluid (CSF) of 38 individuals carrying pathogenic or unclear rare mutations or the common PSEN1 p.E318G variant and compared with Aβ1–42 and Aβ1–40 CSF levels. The soluble sAPPα and sAPPβ species were also measured for the first time in mutation carriers. Results A known pathogenic mutation was identified in 5.7% of EOAD patients (4.6% PSEN1, 1.07% APP) and in 0.3% of LOAD patients. Furthermore, 12 known variants with unclear pathogenicity and 11 novel were identified. Pathogenic and unclear mutation carriers showed a significant reduction in CSF Aβ1–43 levels compared to controls (p = 0.037; < 0.001). CSF Aβ1–43 levels positively correlated with CSF Aβ1–42 in both pathogenic and unclear carriers and controls (all p < 0.001). The p.E318G carriers showed reduced Aβ1–43 levels (p < 0.001), though genetic association with AD was not detected. sAPPα and sAPPβ CSF levels were significantly reduced in the group of unclear (p = 0.006; 0.005) and p.E318G carriers (p = 0.004; 0.039), suggesting their possible involvement in AD. Finally, using Aβ1–43 and Aβ1–42 levels, we could re-classify as “likely pathogenic” 3 of the unclear mutations. Conclusion This is the first time that Aβ1–43 levels were analysed in CSF of AD patients with genetic mutations in the AD causal genes. The observed reduction of Aβ1–43 in APP and PSENs carriers highlights the pathogenic role of longer Aβ peptides in AD pathogenesis. Alterations in Aβ1–43 could prove useful in understanding the pathogenicity of unclear APP and PSENs variants, a critical step towards a more efficient genetic counselling.
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Affiliation(s)
- Federica Perrone
- Neurodegenerative Brain Diseases Group, VIB Center for Molecular Neurology, Antwerp, Belgium.,Institute Born-Bunge, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Maria Bjerke
- Institute Born-Bunge, Antwerp, Belgium.,Reference Centre for Biological Markers of Dementia (BIODEM), Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Laboratory of Neurochemistry and Center for Neurosciences, UZ Brussel and Vrije Universiteit Brussel, Brussels, Belgium
| | - Elisabeth Hens
- Neurodegenerative Brain Diseases Group, VIB Center for Molecular Neurology, Antwerp, Belgium.,Institute Born-Bunge, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Department of Neurology and Memory Clinic, Hospital Network Antwerp, Middelheim and Hoge Beuken, Antwerp, Belgium.,Department of Neurology, University Hospital Antwerp, Edegem, Belgium.,Department of Neurology, University Hospital Brussel and Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Anne Sieben
- Neurodegenerative Brain Diseases Group, VIB Center for Molecular Neurology, Antwerp, Belgium.,Institute Born-Bunge, Antwerp, Belgium.,Department of Neurology, University Hospital Ghent and University of Ghent, Ghent, Belgium
| | - Maarten Timmers
- Reference Centre for Biological Markers of Dementia (BIODEM), Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Janssen Research and Development, Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Arne De Roeck
- Neurodegenerative Brain Diseases Group, VIB Center for Molecular Neurology, Antwerp, Belgium.,Institute Born-Bunge, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Rik Vandenberghe
- Department of Neurosciences, Faculty of Medicine, KU Leuven, Louvain, Belgium.,Laboratory of Cognitive Neurology, Department of Neurology, University Hospitals Leuven, Louvain, Belgium
| | - Kristel Sleegers
- Neurodegenerative Brain Diseases Group, VIB Center for Molecular Neurology, Antwerp, Belgium.,Institute Born-Bunge, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | | | - Peter P De Deyn
- Institute Born-Bunge, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Department of Neurology and Memory Clinic, Hospital Network Antwerp, Middelheim and Hoge Beuken, Antwerp, Belgium
| | - Sebastiaan Engelborghs
- Reference Centre for Biological Markers of Dementia (BIODEM), Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Department of Neurology, University Hospital Brussel and Center for Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Julie van der Zee
- Neurodegenerative Brain Diseases Group, VIB Center for Molecular Neurology, Antwerp, Belgium.,Institute Born-Bunge, Antwerp, Belgium.,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Christine Van Broeckhoven
- Neurodegenerative Brain Diseases Group, VIB Center for Molecular Neurology, Antwerp, Belgium. .,Institute Born-Bunge, Antwerp, Belgium. .,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.
| | - Rita Cacace
- Neurodegenerative Brain Diseases Group, VIB Center for Molecular Neurology, Antwerp, Belgium. .,Institute Born-Bunge, Antwerp, Belgium. .,Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.
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24
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Substrate recruitment by γ-secretase. Semin Cell Dev Biol 2020; 105:54-63. [DOI: 10.1016/j.semcdb.2020.03.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 03/18/2020] [Accepted: 03/20/2020] [Indexed: 12/27/2022]
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25
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Tambini MD, D'Adamio L. Knock-in rats with homozygous PSEN1L435F Alzheimer mutation are viable and show selective γ-secretase activity loss causing low Aβ40/42 and high Aβ43. J Biol Chem 2020; 295:7442-7451. [PMID: 32265300 PMCID: PMC7247318 DOI: 10.1074/jbc.ra120.012542] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 04/01/2020] [Indexed: 12/20/2022] Open
Abstract
Familial forms of Alzheimer's disease (FAD) are caused by mutations in the gene encoding amyloid precursor protein, whose processing can result in formation of β-amyloid (Aβ). FAD can also result from mutations in the presenilin 1/2 (PSEN1/2) genes, whose protein products partially compose the γ-secretase complex that cleaves Aβ from amyloid precursor protein fragments. Psen1 KO mice and knock-in (KI) mice with homozygous FAD-associated L435F mutations (Psen1LF/LF ) are embryonic and perinatally lethal, precluding a more rigorous examination of the effect of Alzheimer's disease-causing Psen1 mutations on neurodegeneration. Given that the rat is a more suitable model organism with regard to surgical interventions and behavioral testing, we generated a rat KI model of the Psen1LF mutation. In this study, we focused on young Psen1LF rats to determine potential early pathogenic changes caused by this mutation. We found that, unlike Psen1LF/LF mice, Psen1LF/LF rats survive into adulthood despite loss of γ-secretase activity. Consistent with loss of γ-secretase function, Psen1LF/LF rats exhibited low levels of Aβ38, Aβ40, and Aβ42 peptides. In contrast, levels of Aβ43, a longer and potentially more amyloidogenic Aβ form, were significantly increased in Psen1LF/LF and Psen1LF/w rats. The longer survival of these KI rats affords the opportunity to examine the effect of homozygous Psen1 Alzheimer's disease-associated mutations on neurodegeneration in older animals.
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Affiliation(s)
- Marc D Tambini
- Department of Pharmacology, Physiology, and Neuroscience, the Brain Health Institute, the Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research of Rutgers New Jersey Medical School, Newark, New Jersey 07103
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology, and Neuroscience, the Brain Health Institute, the Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research of Rutgers New Jersey Medical School, Newark, New Jersey 07103.
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26
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Chávez-Gutiérrez L, Szaruga M. Mechanisms of neurodegeneration - Insights from familial Alzheimer's disease. Semin Cell Dev Biol 2020; 105:75-85. [PMID: 32418657 DOI: 10.1016/j.semcdb.2020.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 03/13/2020] [Accepted: 03/16/2020] [Indexed: 12/18/2022]
Abstract
The rising prevalence of Alzheimer's disease (AD), together with the lack of effective treatments, portray it as one of the major health challenges of our times. Untangling AD implies advancing the knowledge of the biology that gets disrupted during the disease while deciphering the molecular and cellular mechanisms leading to AD-related neurodegeneration. In fact, a solid mechanistic understanding of the disease processes stands as an essential prerequisite for the development of safe and effective treatments. Genetics has provided invaluable clues to the genesis of the disease by revealing deterministic genes - Presenilins (PSENs) and the Amyloid Precursor Protein (APP) - that, when affected, lead in an autosomal dominant manner to early-onset, familial AD (FAD). PSEN is the catalytic subunit of the membrane-embedded γ-secretase complexes, which act as proteolytic switches regulating key cell signalling cascades. Importantly, these intramembrane proteases are responsible for the production of Amyloid β (Aβ) peptides from APP. The convergence of pathogenic mutations on one functional pathway, the amyloidogenic cleavage of APP, strongly supports the significance of this process in AD pathogenesis. Here, we review and discuss the state-of-the-art knowledge of the molecular mechanisms underlying FAD, their implications for the sporadic form of the disease and for the development of safe AD therapeutics.
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Affiliation(s)
- Lucía Chávez-Gutiérrez
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium.
| | - Maria Szaruga
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium; Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
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27
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Trambauer J, Fukumori A, Steiner H. Pathogenic Aβ generation in familial Alzheimer’s disease: novel mechanistic insights and therapeutic implications. Curr Opin Neurobiol 2020; 61:73-81. [DOI: 10.1016/j.conb.2020.01.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/16/2020] [Accepted: 01/23/2020] [Indexed: 01/06/2023]
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28
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Wolfe MS. Unraveling the complexity of γ-secretase. Semin Cell Dev Biol 2020; 105:3-11. [PMID: 31980377 PMCID: PMC7371508 DOI: 10.1016/j.semcdb.2020.01.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/26/2019] [Accepted: 01/15/2020] [Indexed: 01/07/2023]
Abstract
γ-Secretase was initially defined as a proteolytic activity that cleaves within the transmembrane of the amyloid precursor protein (APP) to produce the amyloid β-peptide of Alzheimer's disease. The discovery of mutations in APP and the presenilins associated with familial Alzheimer's disease and their effects on APP processing dovetailed with pharmacological studies on γ-secretase, leading to the revelation that presenilins are unprecedented membrane-embedded aspartyl proteases. Other members of what became known as the γ-secretase complex were subsequently identified. In parallel with these advances, connections between presenilins and Notch receptors essential to metazoan development became evident, resulting in the concurrent realization that γ-secretase also carries out intramembrane proteolysis of Notch as part of its signaling mechanism. Substantial progress has been made toward elucidating how γ-secretase carries out complex processing of transmembrane domains, how it goes awry in familial Alzheimer's disease, the scope of its substrates, and the atomic details of its structure. Critical questions remain for future study, toward further unraveling the complexity of this unique membrane-embedded proteolytic machine and its roles in biology and disease.
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Affiliation(s)
- Michael S Wolfe
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66045, USA.
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29
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Trambauer J, Rodríguez Sarmiento RM, Fukumori A, Feederle R, Baumann K, Steiner H. Aβ43-producing PS1 FAD mutants cause altered substrate interactions and respond to γ-secretase modulation. EMBO Rep 2020; 21:e47996. [PMID: 31762188 PMCID: PMC6945062 DOI: 10.15252/embr.201947996] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 10/28/2019] [Accepted: 10/29/2019] [Indexed: 12/22/2022] Open
Abstract
Abnormal generation of neurotoxic amyloid-β peptide (Aβ) 42/43 species due to mutations in the catalytic presenilin 1 (PS1) subunit of γ-secretase is the major cause of familial Alzheimer's disease (FAD). Deeper mechanistic insight on the generation of Aβ43 is still lacking, and it is unclear whether γ-secretase modulators (GSMs) can reduce the levels of this Aβ species. By comparing several types of Aβ43-generating FAD mutants, we observe that very high levels of Aβ43 are often produced when presenilin function is severely impaired. Altered interactions of C99, the precursor of Aβ, are found for all mutants and are independent of their particular effect on Aβ production. Furthermore, unlike previously described GSMs, the novel compound RO7019009 can effectively lower Aβ43 production of all mutants. Finally, substrate-binding competition experiments suggest that RO7019009 acts mechanistically after initial C99 binding. We conclude that altered C99 interactions are a common feature of diverse types of PS1 FAD mutants and that also patients with Aβ43-generating FAD mutations could in principle be treated by GSMs.
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Affiliation(s)
- Johannes Trambauer
- Biomedical Center (BMC), Metabolic BiochemistryLudwig‐Maximilians‐UniversityMunichGermany
| | | | - Akio Fukumori
- Department of Aging NeurobiologyNational Center for Geriatrics and GerontologyObuJapan
- Department of Mental Health PromotionOsaka University Graduate School of MedicineToyonakaJapan
| | - Regina Feederle
- Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility, Helmholtz Center MunichGerman Research Center for Environmental HealthNeuherbergGermany
- German Center for Neurodegenerative Diseases (DZNE)MunichGermany
| | - Karlheinz Baumann
- Roche Pharma Research and Early DevelopmentRoche Innovation Center Basel, F. Hoffmann‐La Roche Ltd.BaselSwitzerland
| | - Harald Steiner
- Biomedical Center (BMC), Metabolic BiochemistryLudwig‐Maximilians‐UniversityMunichGermany
- German Center for Neurodegenerative Diseases (DZNE)MunichGermany
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30
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Vöglein J, Willem M, Trambauer J, Schönecker S, Dieterich M, Biskup S, Giudici C, Utz K, Oberstein T, Brendel M, Rominger A, Danek A, Steiner H, Haass C, Levin J. Identification of a rare presenilin 1 single amino acid deletion mutation (F175del) with unusual amyloid-β processing effects. Neurobiol Aging 2019; 84:241.e5-241.e11. [DOI: 10.1016/j.neurobiolaging.2019.08.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/22/2019] [Accepted: 08/31/2019] [Indexed: 10/26/2022]
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Abstract
Animal models are indispensable tools for Alzheimer disease (AD) research. Over the course of more than two decades, an increasing number of complementary rodent models has been generated. These models have facilitated testing hypotheses about the aetiology and progression of AD, dissecting the associated pathomechanisms and validating therapeutic interventions, thereby providing guidance for the design of human clinical trials. However, the lack of success in translating rodent data into therapeutic outcomes may challenge the validity of the current models. This Review critically evaluates the genetic and non-genetic strategies used in AD modelling, discussing their strengths and limitations, as well as new opportunities for the development of better models for the disease.
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32
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Abstract
γ-Secretase is a membrane-embedded protease complex, with presenilin as the catalytic component containing two transmembrane aspartates in the active site. With more than 90 known substrates, the γ-secretase complex is considered "the proteasome of the membrane", with central roles in biology and medicine. The protease carries out hydrolysis within the lipid bilayer to cleave the transmembrane domain of the substrate multiple times before releasing secreted products. For many years, elucidation of γ-secretase structure and function largely relied on small-molecule probes and mutagenesis. Recently, however, advances in cryo-electron microscopy have led to the first detailed structures of the protease complex. Two new reports of structures of γ-secretase bound to membrane protein substrates provide great insight into the nature of substrate recognition and how Alzheimer's disease-causing mutations in presenilin might alter substrate binding and processing. These new structures offer a powerful platform for elucidating enzyme mechanisms, deciphering effects of disease-causing mutations, and advancing Alzheimer's disease drug discovery.
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Affiliation(s)
- Michael S Wolfe
- Department of Medicinal Chemistry , University of Kansas , Lawrence , Kansas 66045 , United States
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33
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Shen L, Qin W, Wu L, Zhou A, Tang Y, Wang Q, Jia L, Jia J. Two novel presenilin-1 mutations (I249L and P433S) in early onset Chinese Alzheimer's pedigrees and their functional characterization. Biochem Biophys Res Commun 2019; 516:264-269. [PMID: 31235249 DOI: 10.1016/j.bbrc.2019.05.185] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 05/30/2019] [Indexed: 01/02/2023]
Abstract
Clinical case study and functional characterization of the disease-associated presenilin-1 (PSEN1) mutations may help reveal the roles of PSEN1 in the pathogenesis of Alzheimer's disease (AD). By mutation screening of PSEN1, presenilin-2, and amyloid precursor protein genes in two Chinese Alzheimer's pedigrees, we identified two novel PSEN1 mutations, I249L and P433S. The two probands presented with progressive memory decline and subsequent psychiatric symptoms, with the age of onset at 54 and 34 years old, respectively. The effects of these two mutations on presenilin-1 endoproteolysis and β-amyloid (Aβ) production were examined in SH-SY5Y neuroblastoma cells infected with lentiviruses expressing presenilin-1 wild type (WT), I249L and P433S mutants. Both mutants showed increased Aβ42 levels and Aβ42/Aβ40 ratios. However, the I249L did not affect presenilin-1 endoproteolysis or Aβ43 production, whereas the P433S mutant inhibited presenilin-1 endoproteolysis and enhanced Aβ43 production. Our findings suggest that both I249L and P433S are pathogenic for early onset of AD by increasing Aβ42 production and Aβ42/Aβ40 ratios. Furthermore, P433S may contribute to the very early onset of AD by inhibiting PS1 endoproteolysis and enhancing the production of longer Aβ peptide Aβ43.
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Affiliation(s)
- Luxi Shen
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Wei Qin
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Liyong Wu
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Aihong Zhou
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Yi Tang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Qi Wang
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Longfei Jia
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China
| | - Jianping Jia
- Innovation Center for Neurological Disorders, Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, 100053, PR China; Beijing Key Laboratory of Geriatric Cognitive Disorders, Beijing, 100053, PR China; Clinical Center for Neurodegenerative Disease and Memory Impairment, Capital Medical University, Beijing, 100053, PR China; Center of Alzheimer's Disease, Beijing Institute for Brain Disorders, Beijing, 100053, PR China; Key Laboratory of Neurodegenerative Diseases, Ministry of Education, Beijing, 100053, PR China; National Clinical Research Center for Geriatric Disorders, Beijing, 100053, PR China.
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34
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Cline EN, Bicca MA, Viola KL, Klein WL. The Amyloid-β Oligomer Hypothesis: Beginning of the Third Decade. J Alzheimers Dis 2019; 64:S567-S610. [PMID: 29843241 PMCID: PMC6004937 DOI: 10.3233/jad-179941] [Citation(s) in RCA: 520] [Impact Index Per Article: 104.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The amyloid-β oligomer (AβO) hypothesis was introduced in 1998. It proposed that the brain damage leading to Alzheimer’s disease (AD) was instigated by soluble, ligand-like AβOs. This hypothesis was based on the discovery that fibril-free synthetic preparations of AβOs were potent CNS neurotoxins that rapidly inhibited long-term potentiation and, with time, caused selective nerve cell death (Lambert et al., 1998). The mechanism was attributed to disrupted signaling involving the tyrosine-protein kinase Fyn, mediated by an unknown toxin receptor. Over 4,000 articles concerning AβOs have been published since then, including more than 400 reviews. AβOs have been shown to accumulate in an AD-dependent manner in human and animal model brain tissue and, experimentally, to impair learning and memory and instigate major facets of AD neuropathology, including tau pathology, synapse deterioration and loss, inflammation, and oxidative damage. As reviewed by Hayden and Teplow in 2013, the AβO hypothesis “has all but supplanted the amyloid cascade.” Despite the emerging understanding of the role played by AβOs in AD pathogenesis, AβOs have not yet received the clinical attention given to amyloid plaques, which have been at the core of major attempts at therapeutics and diagnostics but are no longer regarded as the most pathogenic form of Aβ. However, if the momentum of AβO research continues, particularly efforts to elucidate key aspects of structure, a clear path to a successful disease modifying therapy can be envisioned. Ensuring that lessons learned from recent, late-stage clinical failures are applied appropriately throughout therapeutic development will further enable the likelihood of a successful therapy in the near-term.
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Affiliation(s)
- Erika N Cline
- Department of Neurobiology, Cognitive Neurology and Alzheimer's Disease Center, International Institute for Nanotechnology, and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - Maíra Assunção Bicca
- Department of Neurobiology, Cognitive Neurology and Alzheimer's Disease Center, International Institute for Nanotechnology, and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - Kirsten L Viola
- Department of Neurobiology, Cognitive Neurology and Alzheimer's Disease Center, International Institute for Nanotechnology, and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
| | - William L Klein
- Department of Neurobiology, Cognitive Neurology and Alzheimer's Disease Center, International Institute for Nanotechnology, and Chemistry of Life Processes Institute, Northwestern University, Evanston, IL, USA
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35
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Lessard CB, Rodriguez E, Ladd TB, Minter LM, Osborne BA, Miele L, Golde TE, Ran Y. Individual and combined presenilin 1 and 2 knockouts reveal that both have highly overlapping functions in HEK293T cells. J Biol Chem 2019; 294:11276-11285. [PMID: 31167792 DOI: 10.1074/jbc.ra119.008041] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/30/2019] [Indexed: 01/13/2023] Open
Abstract
Presenilins 1 and 2 (PS1 and 2) are the catalytic subunits of γ-secretase, a multiprotein protease that cleaves amyloid protein precursor and other type I transmembrane proteins. Previous studies with mouse models or cells have indicated differences in PS1 and PS2 functions. We have recently reported that clinical γ-secretase inhibitors (GSIs), initially developed to manage Alzheimer's disease and now being considered for other therapeutic interventions, are both pharmacologically and functionally distinct. Here, using CRISPR/Cas9-based gene editing, we established human HEK 293T cell lines in which endogenous PS1, PS2, or both have been knocked out. Using these knockout lines to examine differences in PS1- and PS2-mediated cleavage events, we confirmed that PS2 generates more intracellular β-amyloid than does PS1. Moreover, we observed subtle differences in PS1- and PS2-mediated cleavages of select substrates. In exploring the question of whether differences in activity among clinical GSIs could be attributed to differential inhibition of PS1 or PS2, we noted that select GSIs inhibit PS1 and PS2 activities on specific substrates with slightly different potencies. We also found that endoproteolysis of select PS1 FAD-linked variants in human cells is more efficient than what has been previously reported for mouse cell lines. Overall, these results obtained with HEK293T cells suggest that selective PS1 or PS2 inhibition by a given GSI does not explain the previously observed differences in functional and pharmacological properties among various GSIs.
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Affiliation(s)
- Christian B Lessard
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Edgardo Rodriguez
- Department of Pharmacology and Therapeutics, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
| | - Thomas B Ladd
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Lisa M Minter
- Department of Veterinary and Animal Sciences, Center for Bioactive Delivery, Institute for Applied Life Sciences, and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Barbara A Osborne
- Department of Veterinary and Animal Sciences, Center for Bioactive Delivery, Institute for Applied Life Sciences, and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Lucio Miele
- Department of Genetics and Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112
| | - Todd E Golde
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Yong Ran
- Department of Neuroscience and Neurology, Center for Translational Research in Neurodegenerative Disease, and McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida 32610
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Götz A, Mylonas N, Högel P, Silber M, Heinel H, Menig S, Vogel A, Feyrer H, Huster D, Luy B, Langosch D, Scharnagl C, Muhle-Goll C, Kamp F, Steiner H. Modulating Hinge Flexibility in the APP Transmembrane Domain Alters γ-Secretase Cleavage. Biophys J 2019; 116:2103-2120. [PMID: 31130234 PMCID: PMC6554489 DOI: 10.1016/j.bpj.2019.04.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/14/2019] [Accepted: 04/15/2019] [Indexed: 01/27/2023] Open
Abstract
Intramembrane cleavage of the β-amyloid precursor protein C99 substrate by γ-secretase is implicated in Alzheimer's disease pathogenesis. Biophysical data have suggested that the N-terminal part of the C99 transmembrane domain (TMD) is separated from the C-terminal cleavage domain by a di-glycine hinge. Because the flexibility of this hinge might be critical for γ-secretase cleavage, we mutated one of the glycine residues, G38, to a helix-stabilizing leucine and to a helix-distorting proline. Both mutants impaired γ-secretase cleavage and also altered its cleavage specificity. Circular dichroism, NMR, and backbone amide hydrogen/deuterium exchange measurements as well as molecular dynamics simulations showed that the mutations distinctly altered the intrinsic structural and dynamical properties of the substrate TMD. Although helix destabilization and/or unfolding was not observed at the initial ε-cleavage sites of C99, subtle changes in hinge flexibility were identified that substantially affected helix bending and twisting motions in the entire TMD. These resulted in altered orientation of the distal cleavage domain relative to the N-terminal TMD part. Our data suggest that both enhancing and reducing local helix flexibility of the di-glycine hinge may decrease the occurrence of enzyme-substrate complex conformations required for normal catalysis and that hinge mobility can thus be conducive for productive substrate-enzyme interactions.
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Affiliation(s)
- Alexander Götz
- Physics of Synthetic Biological Systems (E14), Technical University of Munich, Freising, Germany
| | - Nadine Mylonas
- Biomedical Center (BMC), Metabolic Biochemistry, Ludwig-Maximilians-University, Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Philipp Högel
- Center for Integrated Protein Science Munich at the Lehrstuhl Chemie der Biopolymere, Technical University Munich, Freising, Germany
| | - Mara Silber
- Institute of Organic Chemistry and Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Hannes Heinel
- Institute for Medical Physics and Biophysics, Leipzig University, Leipzig, Germany
| | - Simon Menig
- Physics of Synthetic Biological Systems (E14), Technical University of Munich, Freising, Germany
| | - Alexander Vogel
- Institute for Medical Physics and Biophysics, Leipzig University, Leipzig, Germany
| | - Hannes Feyrer
- Institute of Organic Chemistry and Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Daniel Huster
- Institute for Medical Physics and Biophysics, Leipzig University, Leipzig, Germany
| | - Burkhard Luy
- Institute of Organic Chemistry and Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Dieter Langosch
- Center for Integrated Protein Science Munich at the Lehrstuhl Chemie der Biopolymere, Technical University Munich, Freising, Germany
| | - Christina Scharnagl
- Physics of Synthetic Biological Systems (E14), Technical University of Munich, Freising, Germany.
| | - Claudia Muhle-Goll
- Institute of Organic Chemistry and Institute for Biological Interfaces 4, Karlsruhe Institute of Technology, Karlsruhe, Germany.
| | - Frits Kamp
- Biomedical Center (BMC), Metabolic Biochemistry, Ludwig-Maximilians-University, Munich, Germany
| | - Harald Steiner
- Biomedical Center (BMC), Metabolic Biochemistry, Ludwig-Maximilians-University, Munich, Germany; German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.
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Steiner H, Fukumori A, Tagami S, Okochi M. Making the final cut: pathogenic amyloid-β peptide generation by γ-secretase. Cell Stress 2018; 2:292-310. [PMID: 31225454 PMCID: PMC6551803 DOI: 10.15698/cst2018.11.162] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alzheimer´s disease (AD) is a devastating neurodegenerative disease of the elderly population. Genetic evidence strongly suggests that aberrant generation and/or clearance of the neurotoxic amyloid-β peptide (Aβ) is triggering the disease. Aβ is generated from the amyloid precursor protein (APP) by the sequential cleavages of β- and γ-secretase. The latter cleavage by γ-secretase, a unique and fascinating four-component protease complex, occurs in the APP transmembrane domain thereby releasing Aβ species of 37-43 amino acids in length including the longer, highly pathogenic peptides Aβ42 and Aβ43. The lack of a precise understanding of Aβ generation as well as of the functions of other γ-secretase substrates has been one factor underlying the disappointing failure of γ-secretase inhibitors in clinical trials, but on the other side also been a major driving force for structural and in depth mechanistic studies on this key AD drug target in the past few years. Here we review recent breakthroughs in our understanding of how the γ-secretase complex recognizes substrates, of how it binds and processes β-secretase cleaved APP into different Aβ species, as well as the progress made on a question of outstanding interest, namely how clinical AD mutations in the catalytic subunit presenilin and the γ-secretase cleavage region of APP lead to relative increases of Aβ42/43. Finally, we discuss how the knowledge emerging from these studies could be used to therapeutically target this enzyme in a safe way.
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Affiliation(s)
- Harald Steiner
- Biomedical Center (BMC), Metabolic Biochemistry, Ludwig-Maximilians-University Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Akio Fukumori
- Department of Aging Neurobiology, National Center for Geriatrics and Gerontology, Obu & Department of Mental Health Promotion, Osaka University Graduate School of Medicine, Toyonaka, Japan
| | - Shinji Tagami
- Neuropsychiatry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masayasu Okochi
- Neuropsychiatry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
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Tiwari S, Atluri VSR, Yndart Arias A, Jayant RD, Kaushik A, Geiger J, Nair MN. Withaferin A Suppresses Beta Amyloid in APP Expressing Cells: Studies for Tat and Cocaine Associated Neurological Dysfunctions. Front Aging Neurosci 2018; 10:291. [PMID: 30356847 PMCID: PMC6190869 DOI: 10.3389/fnagi.2018.00291] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/04/2018] [Indexed: 12/31/2022] Open
Abstract
Neurological disorders are the biggest concern globally. Out of ~36 million human immunodeficiency virus (HIV) positive people, about 30%-60% exhibit neurological disorders, including dementia and Alzheimer's disease (AD) like pathology. In AD or AD like neurological disorders, the pathogenesis is mainly due to the abnormal accumulation of extracellular amyloid beta (Aβ). In this era of antiretroviral therapy, the life span of the HIV-infected individuals has increased leading towards increased neurocognitive dysfunction in nearly 30% of HIV-infected individuals, specifically older people. Deposition of the Aβ plaques in the CNS is one the major phenomenon happening in aging HIV patients. ART suppresses the viral replication, but the neurotoxic protein (Tat) is still produced and results in increased levels of Aβ. Furthermore, drugs of abuse like cocaine (coc) is known to induce the HIV associated neurocognitive disorders as well as the Aβ secretion. To target the Tat and coc induced Aβ secretion, we propose a potent bifunctional molecule Withaferin A (WA) which may act as a neuro-protectant against Aβ neurotoxicity. In this study, we show that WA reduces secreted Aβ and induced neurotoxicity in amyloid precursor protein (APP)-plasmid transfected SH-SY5Y cells (SH-APP). In this study, we show that in SH-APP cells, Aβ secretion is induced in the presence of HIV-1 Tat (neurotoxic) and drug of abuse coc. Our fluorescent microscopy studies show the increased concentration of Aβ40 in Tat (50 ng/ml) and coc (0.1 μM) treated SH-APP cells as compared to control. Our dose optimization study show, lower concentrations (0.5-2 μM) of WA significantly reduce the Aβ40 levels, without inducing cytotoxicity in the SH-APP cells. Additionally, WA reduces the Tat and cocaine induced Aβ levels. Therefore, we propose that Aβ aggregation is induced by the presence of Tat and coc and WA is potent in reducing the secreted Aβ and induced neurotoxicity. Our study provides new opportunities for exploring the pathophysiology and targeting the neurological disorders.
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Affiliation(s)
- Sneham Tiwari
- Institute of NeuroImmune Pharmacology, Center for Personalized Nanomedicine, Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States
| | - Venkata Subba Rao Atluri
- Institute of NeuroImmune Pharmacology, Center for Personalized Nanomedicine, Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States
| | - Adriana Yndart Arias
- Institute of NeuroImmune Pharmacology, Center for Personalized Nanomedicine, Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States
| | - Rahul Dev Jayant
- Institute of NeuroImmune Pharmacology, Center for Personalized Nanomedicine, Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States
| | - Ajeet Kaushik
- Institute of NeuroImmune Pharmacology, Center for Personalized Nanomedicine, Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States
| | - Jonathan Geiger
- Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, United States
| | - Madhavan N Nair
- Institute of NeuroImmune Pharmacology, Center for Personalized Nanomedicine, Department of Immunology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States
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A key role for MAM in mediating mitochondrial dysfunction in Alzheimer disease. Cell Death Dis 2018; 9:335. [PMID: 29491396 PMCID: PMC5832428 DOI: 10.1038/s41419-017-0215-0] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/27/2017] [Accepted: 12/06/2017] [Indexed: 12/19/2022]
Abstract
In the last few years, increased emphasis has been devoted to understanding the contribution of mitochondria-associated endoplasmic reticulum (ER) membranes (MAM) to human pathology in general, and neurodegenerative diseases in particular. A major reason for this is the central role that this subdomain of the ER plays in metabolic regulation and in mitochondrial biology. As such, aberrant MAM function may help explain the seemingly unrelated metabolic abnormalities often seen in neurodegeneration. In the specific case of Alzheimer disease (AD), besides perturbations in calcium and lipid homeostasis, there are numerous documented alterations in mitochondrial behavior and function, including reduced respiratory chain activity and oxidative phosphorylation, increased free radical production, and altered organellar morphology, dynamics, and positioning (especially perinuclear mitochondria). However, whether these alterations are primary events causative of the disease, or are secondary downstream events that are the result of some other, more fundamental problem, is still unclear. In support of the former possibility, we recently reported that C99, the C-terminal processing product of the amyloid precursor protein (APP) derived from its cleavage by β-secretase, is present in MAM, that its level is increased in AD, and that this increase reduces mitochondrial respiration, likely via a C99-induced alteration in cellular sphingolipid homeostasis. Thus, the metabolic disturbances seen in AD likely arise from increased ER-mitochondrial communication that is driven by an increase in the levels of C99 at the MAM.
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40
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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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41
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Pimenova AA, Raj T, Goate AM. Untangling Genetic Risk for Alzheimer's Disease. Biol Psychiatry 2018; 83:300-310. [PMID: 28666525 PMCID: PMC5699970 DOI: 10.1016/j.biopsych.2017.05.014] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/15/2017] [Accepted: 05/15/2017] [Indexed: 01/01/2023]
Abstract
Alzheimer's disease (AD) is a genetically heterogeneous neurodegenerative disorder caused by fully penetrant single gene mutations in a minority of cases, while the majority of cases are sporadic or show modest familial clustering. These cases are of late onset and likely result from the interaction of many genes and the environment. More than 30 loci have been implicated in AD by a combination of linkage, genome-wide association, and whole genome/exome sequencing. We have learned from these studies that perturbations in endolysosomal, lipid metabolism, and immune response pathways substantially contribute to sporadic AD pathogenesis. We review here current knowledge about functions of AD susceptibility genes, highlighting cells of the myeloid lineage as drivers of at least part of the genetic component in late-onset AD. Although targeted resequencing utilized for the identification of causal variants has discovered coding mutations in some AD-associated genes, a lot of risk variants lie in noncoding regions. Here we discuss the use of functional genomics approaches that integrate transcriptomic, epigenetic, and endophenotype traits with systems biology to annotate genetic variants, and to facilitate discovery of AD risk genes. Further validation in cell culture and mouse models will be necessary to establish causality for these genes. This knowledge will allow mechanism-based design of novel therapeutic interventions in AD and promises coherent implementation of treatment in a personalized manner.
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Affiliation(s)
- Anna A Pimenova
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York; Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Towfique Raj
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York; Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Alison M Goate
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York; Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York.
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42
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Moore BD, Martin J, de Mena L, Sanchez J, Cruz PE, Ceballos-Diaz C, Ladd TB, Ran Y, Levites Y, Kukar TL, Kurian JJ, McKenna R, Koo EH, Borchelt DR, Janus C, Rincon-Limas D, Fernandez-Funez P, Golde TE. Short Aβ peptides attenuate Aβ42 toxicity in vivo. J Exp Med 2017; 215:283-301. [PMID: 29208777 PMCID: PMC5748850 DOI: 10.1084/jem.20170600] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 08/18/2017] [Accepted: 10/04/2017] [Indexed: 01/05/2023] Open
Abstract
Data demonstrate that short amyloid-β (Aβ) peptides are not toxic in vivo and can partially block toxicity associated with Aβ42 accumulation. Moore et al. further validate the use of γ-secretase modulators that lower Aβ42 and increase short Aβs as potential Alzheimer’s disease therapeutics. Processing of amyloid-β (Aβ) precursor protein (APP) by γ-secretase produces multiple species of Aβ: Aβ40, short Aβ peptides (Aβ37–39), and longer Aβ peptides (Aβ42–43). γ-Secretase modulators, a class of Alzheimer’s disease therapeutics, reduce production of the pathogenic Aβ42 but increase the relative abundance of short Aβ peptides. To evaluate the pathological relevance of these peptides, we expressed Aβ36–40 and Aβ42–43 in Drosophila melanogaster to evaluate inherent toxicity and potential modulatory effects on Aβ42 toxicity. In contrast to Aβ42, the short Aβ peptides were not toxic and, when coexpressed with Aβ42, were protective in a dose-dependent fashion. In parallel, we explored the effects of recombinant adeno-associated virus–mediated expression of Aβ38 and Aβ40 in mice. When expressed in nontransgenic mice at levels sufficient to drive Aβ42 deposition, Aβ38 and Aβ40 did not deposit or cause behavioral alterations. These studies indicate that treatments that lower Aβ42 by raising the levels of short Aβ peptides could attenuate the toxic effects of Aβ42.
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Affiliation(s)
- Brenda D Moore
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Jason Martin
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Lorena de Mena
- McKnight Brain Institute, University of Florida, Gainesville, FL.,Department of Neurology, University of Florida, Gainesville, FL
| | - Jonatan Sanchez
- McKnight Brain Institute, University of Florida, Gainesville, FL.,Department of Neurology, University of Florida, Gainesville, FL
| | - Pedro E Cruz
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Carolina Ceballos-Diaz
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Thomas B Ladd
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Yong Ran
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Yona Levites
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Thomas L Kukar
- Department of Pharmacology and Neurology, Emory University School of Medicine, Atlanta, GA
| | - Justin J Kurian
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL
| | - Edward H Koo
- Department of Neuroscience, University of California, San Diego, La Jolla, CA
| | - David R Borchelt
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Christopher Janus
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL.,McKnight Brain Institute, University of Florida, Gainesville, FL
| | - Diego Rincon-Limas
- McKnight Brain Institute, University of Florida, Gainesville, FL.,Department of Neurology, University of Florida, Gainesville, FL
| | - Pedro Fernandez-Funez
- Department of Biomedical Sciences, University of Minnesota School of Medicine, Duluth, MN
| | - Todd E Golde
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, FL .,McKnight Brain Institute, University of Florida, Gainesville, FL
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43
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Somavarapu AK, Kepp KP. Membrane Dynamics of γ-Secretase Provides a Molecular Basis for β-Amyloid Binding and Processing. ACS Chem Neurosci 2017; 8:2424-2436. [PMID: 28841371 DOI: 10.1021/acschemneuro.7b00208] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
γ-Secretase produces β-amyloid (Aβ) within its presenilin (PS1) subunit, mutations in which cause Alzheimer's disease, and current therapies thus seek to modulate its activity. While the general structure is known from recent electron microscopy studies, direct loop and membrane interactions and explicit dynamics relevant to substrate processing remain unknown. We report a modeled structure utilizing the optimal multitemplate information available, including loops and missing side chains, account of maturation cleavage, and explicit all-atom molecular dynamics in the membrane. We observe three distinct conformations of γ-secretase (open, semiopen, and closed) that remarkably differ by tilting of helices 2 and 3 of PS1, directly controlling active site availability. The large hydrophilic loop of PS1 where maturation occurs reveals a new helix segment that parallels the likely helix character of other substrates. The semiopen conformation consistently shows the best fit of Aβ peptides, that is, longer residence before release and by inference more trimming. In contrast, the closed, hydrophobic conformation is largely inactive and the open conformation is active but provides fewer optimal interactions and induces shorter residence time and by inference releases Aβ peptides of longer lengths. Our simulations thus provide a molecular basis for substrate processing and changes in the Aβ42/Aβ40 ratio. Accordingly, selective binding to protect the semiopen "innocent" conformation provides a molecular recipe for effective γ-secretase modulators; we provide the full atomic structures for these states that may play a key role in developing selective γ-secretase modulators for treatment of Alzheimer's disease.
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Affiliation(s)
| | - Kasper P. Kepp
- Technical University of Denmark, DTU Chemistry, DK-2800 Kongens Lyngby, Denmark
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44
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Langosch D, Steiner H. Substrate processing in intramembrane proteolysis by γ-secretase - the role of protein dynamics. Biol Chem 2017; 398:441-453. [PMID: 27845877 DOI: 10.1515/hsz-2016-0269] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/08/2016] [Indexed: 01/31/2023]
Abstract
Intramembrane proteases comprise a number of different membrane proteins with different types of catalytic sites. Their common denominator is cleavage within the plane of the membrane, which usually results in peptide bond scission within the transmembrane helices of their substrates. Despite recent progress in the determination of high-resolution structures, as illustrated here for the γ-secretase complex and its substrate C99, it is still unknown how these enzymes function and how they distinguish between substrates and non-substrates. In principle, substrate/non-substrate discrimination could occur at the level of substrate binding and/or cleavage. Focusing on the γ-secretase/C99 pair, we will discuss recent observations suggesting that global motions within a substrate transmembrane helix may be much more important for defining a substrate than local unraveling at cleavage sites.
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45
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Cieplak AS. Protein folding, misfolding and aggregation: The importance of two-electron stabilizing interactions. PLoS One 2017; 12:e0180905. [PMID: 28922400 PMCID: PMC5603215 DOI: 10.1371/journal.pone.0180905] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 06/22/2017] [Indexed: 12/17/2022] Open
Abstract
Proteins associated with neurodegenerative diseases are highly pleiomorphic and may adopt an all-α-helical fold in one environment, assemble into all-β-sheet or collapse into a coil in another, and rapidly polymerize in yet another one via divergent aggregation pathways that yield broad diversity of aggregates’ morphology. A thorough understanding of this behaviour may be necessary to develop a treatment for Alzheimer’s and related disorders. Unfortunately, our present comprehension of folding and misfolding is limited for want of a physicochemical theory of protein secondary and tertiary structure. Here we demonstrate that electronic configuration and hyperconjugation of the peptide amide bonds ought to be taken into account to advance such a theory. To capture the effect of polarization of peptide linkages on conformational and H-bonding propensity of the polypeptide backbone, we introduce a function of shielding tensors of the Cα atoms. Carrying no information about side chain-side chain interactions, this function nonetheless identifies basic features of the secondary and tertiary structure, establishes sequence correlates of the metamorphic and pH-driven equilibria, relates binding affinities and folding rate constants to secondary structure preferences, and manifests common patterns of backbone density distribution in amyloidogenic regions of Alzheimer’s amyloid β and tau, Parkinson’s α-synuclein and prions. Based on those findings, a split-intein like mechanism of molecular recognition is proposed to underlie dimerization of Aβ, tau, αS and PrPC, and divergent pathways for subsequent association of dimers are outlined; a related mechanism is proposed to underlie formation of PrPSc fibrils. The model does account for: (i) structural features of paranuclei, off-pathway oligomers, non-fibrillar aggregates and fibrils; (ii) effects of incubation conditions, point mutations, isoform lengths, small-molecule assembly modulators and chirality of solid-liquid interface on the rate and morphology of aggregation; (iii) fibril-surface catalysis of secondary nucleation; and (iv) self-propagation of infectious strains of mammalian prions.
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Affiliation(s)
- Andrzej Stanisław Cieplak
- Department of Chemistry, Bilkent University, Ankara, Turkey
- Department of Chemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, United States of America
- * E-mail:
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Schedin-Weiss S, Inoue M, Hromadkova L, Teranishi Y, Yamamoto NG, Wiehager B, Bogdanovic N, Winblad B, Sandebring-Matton A, Frykman S, Tjernberg LO. Monoamine oxidase B is elevated in Alzheimer disease neurons, is associated with γ-secretase and regulates neuronal amyloid β-peptide levels. ALZHEIMERS RESEARCH & THERAPY 2017; 9:57. [PMID: 28764767 PMCID: PMC5540560 DOI: 10.1186/s13195-017-0279-1] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 06/21/2017] [Indexed: 01/03/2023]
Abstract
Background Increased levels of the pathogenic amyloid β-peptide (Aβ), released from its precursor by the transmembrane protease γ-secretase, are found in Alzheimer disease (AD) brains. Interestingly, monoamine oxidase B (MAO-B) activity is also increased in AD brain, but its role in AD pathogenesis is not known. Recent neuroimaging studies have shown that the increased MAO-B expression in AD brain starts several years before the onset of the disease. Here, we show a potential connection between MAO-B, γ-secretase and Aβ in neurons. Methods MAO-B immunohistochemistry was performed on postmortem human brain. Affinity purification of γ-secretase followed by mass spectrometry was used for unbiased identification of γ-secretase-associated proteins. The association of MAO-B with γ-secretase was studied by coimmunoprecipitation from brain homogenate, and by in-situ proximity ligation assay (PLA) in neurons as well as mouse and human brain sections. The effect of MAO-B on Aβ production and Notch processing in cell cultures was analyzed by siRNA silencing or overexpression experiments followed by ELISA, western blot or FRET analysis. Methodology for measuring relative intraneuronal MAO-B and Aβ42 levels in single cells was developed by combining immunocytochemistry and confocal microscopy with quantitative image analysis. Results Immunohistochemistry revealed MAO-B staining in neurons in the frontal cortex, hippocampus CA1 and entorhinal cortex in postmortem human brain. Interestingly, the neuronal staining intensity was higher in AD brain than in control brain in these regions. Mass spectrometric data from affinity purified γ-secretase suggested that MAO-B is a γ-secretase-associated protein, which was confirmed by immunoprecipitation and PLA, and a neuronal location of the interaction was shown. Strikingly, intraneuronal Aβ42 levels correlated with MAO-B levels, and siRNA silencing of MAO-B resulted in significantly reduced levels of intraneuronal Aβ42. Furthermore, overexpression of MAO-B enhanced Aβ production. Conclusions This study shows that MAO-B levels are increased not only in astrocytes but also in pyramidal neurons in AD brain. The study also suggests that MAO-B regulates Aβ production in neurons via γ-secretase and thereby provides a key to understanding the relationship between MAO-B and AD pathogenesis. Potentially, the γ-secretase/MAO-B association may be a target for reducing Aβ levels using protein–protein interaction breakers. Electronic supplementary material The online version of this article (doi:10.1186/s13195-017-0279-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sophia Schedin-Weiss
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden.
| | - Mitsuhiro Inoue
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden.,Present address: Dainippon Sumitomo Pharma Co., Ltd, Drug Development Research Laboratories, Osaka, Japan
| | - Lenka Hromadkova
- National Institute of Mental Health, Klecany, Czech Republic.,Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Yasuhiro Teranishi
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden.,Present address: Dainippon Sumitomo Pharma Co., Ltd, Drug Development Research Laboratories, Osaka, Japan
| | - Natsuko Goto Yamamoto
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden.,Present address: Dainippon Sumitomo Pharma Co., Ltd, Drug Development Research Laboratories, Osaka, Japan
| | - Birgitta Wiehager
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden
| | - Nenad Bogdanovic
- Department of Geriatric Medicine, University in Oslo, Memory Clinic, Oslo University Hospital, Oslo, Norway
| | - Bengt Winblad
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden
| | - Anna Sandebring-Matton
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden
| | - Susanne Frykman
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden
| | - Lars O Tjernberg
- Karolinska Institutet, Department NVS, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden
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Veugelen S, Saito T, Saido TC, Chávez-Gutiérrez L, De Strooper B. Familial Alzheimer's Disease Mutations in Presenilin Generate Amyloidogenic Aβ Peptide Seeds. Neuron 2017; 90:410-6. [PMID: 27100199 DOI: 10.1016/j.neuron.2016.03.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 12/24/2015] [Accepted: 03/10/2016] [Indexed: 01/15/2023]
Abstract
Recently it was proposed that the familial Alzheimer's disease (FAD) causing presenilin (PSEN) mutations PSEN1-L435F and PSEN1-C410Y do not support the generation of Aβ-peptides from the amyloid precursor protein (APP). This challenges the amyloid hypothesis and disagrees with previous work showing that PSEN1 FAD causing mutations generate invariably long Aβ and seed amyloid. We contrast here the proteolytic activities of these mutant PSEN alleles with the complete loss-of-function PSEN1-D257A allele. We find residual carboxy- and endo-peptidase γ-secretase activities, similar to the formerly characterized PSEN1-R278I. We conclude that the PSEN1-L435F and -C410Y mutations are extreme examples of the previously proposed "dysfunction" of γ-secretase that characterizes FAD-associated PSEN. This Matters Arising paper is in response to Xia et al. (2015), published in Neuron. See also the response by Xia et al. (2016), published in this issue.
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Affiliation(s)
- Sarah Veugelen
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium; Center for Human Genetics, and Leuven Institute for Neurodegenerative Diseases (LIND), University of Leuven (KU Leuven), 3000 Leuven, Belgium
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Lucía Chávez-Gutiérrez
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium; Center for Human Genetics, and Leuven Institute for Neurodegenerative Diseases (LIND), University of Leuven (KU Leuven), 3000 Leuven, Belgium.
| | - Bart De Strooper
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium; Center for Human Genetics, and Leuven Institute for Neurodegenerative Diseases (LIND), University of Leuven (KU Leuven), 3000 Leuven, Belgium; Institute of Neurology, University College London, London, WC1N 3BG, UK.
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Trambauer J, Fukumori A, Kretner B, Steiner H. Analyzing Amyloid-β Peptide Modulation Profiles and Binding Sites of γ-Secretase Modulators. Methods Enzymol 2017; 584:157-183. [DOI: 10.1016/bs.mie.2016.10.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Schröder B, Saftig P. Intramembrane proteolysis within lysosomes. Ageing Res Rev 2016; 32:51-64. [PMID: 27143694 DOI: 10.1016/j.arr.2016.04.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/01/2016] [Accepted: 04/26/2016] [Indexed: 11/26/2022]
Abstract
Regulated intramembrane proteolysis is of pivotal importance in a diverse set of developmental and physiological processes. Altered intramembrane substrate turnover may be associated with neurodegeneration, cancer and impaired immune function. In this review we will focus on the intramembrane proteases which have been localized in the lysosomal membrane. Members of the γ-secretase complex and γ-secretase activity are found in the lysosomal membrane and are discussed to contribute to intracellular amyloid β production. Mutant or deficient γ-secretase may cause disturbed lysosomal function. The signal peptide peptidase-like (SPPL) protease 2a is a lysosomal membrane component and cleaves CD74, the invariant chain of the MHC II complex, as well as FasL, TNF, ITM2B and TMEM106, type II transmembrane proteins involved in the regulation of immunity and neurodegeneration. Therefore, it can be concluded, that not only proteolysis within the lysosomal lumen but also within lysosomal membranes regulates important cellular functions and contributes essentially to proteostasis of membrane proteins what may become increasingly compromised in the aged individual.
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Yao D, Wang J, Wang G, Jiang Y, Shang L, Zhao Y, Huang J, Yang S, Wang J, Yu Y. Design, synthesis and biological evaluation of coumarin derivatives as novel acetylcholinesterase inhibitors that attenuate H2O2-induced apoptosis in SH-SY5Y cells. Bioorg Chem 2016; 68:112-23. [DOI: 10.1016/j.bioorg.2016.07.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/20/2016] [Accepted: 07/25/2016] [Indexed: 01/04/2023]
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