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Maccioni R, Travisan C, Badman J, Zerial S, Wagener A, Andrade-Talavera Y, Picciau F, Grassi C, Chen G, Lemoine L, Fisahn A, Jiang R, Fluhrer R, Mentrup T, Schröder B, Nilsson P, Tambaro S. Signal peptide peptidase-like 2b modulates the amyloidogenic pathway and exhibits an Aβ-dependent expression in Alzheimer's disease. Prog Neurobiol 2024; 235:102585. [PMID: 38367747 DOI: 10.1016/j.pneurobio.2024.102585] [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: 06/30/2023] [Revised: 01/25/2024] [Accepted: 02/08/2024] [Indexed: 02/19/2024]
Abstract
Alzheimer's disease (AD) is a multifactorial disorder driven by abnormal amyloid β-peptide (Aβ) levels. In this study, we investigated the role of presenilin-like signal peptide peptidase-like 2b (SPPL2b) in AD pathophysiology and its potential as a druggable target within the Aβ cascade. Exogenous Aβ42 influenced SPPL2b expression in human cell lines and acute mouse brain slices. SPPL2b and its AD-related substrate BRI2 were evaluated in the brains of AppNL-G-F knock-in AD mice and human postmortem AD brains. An early high cortical expression of SPPL2b was observed, followed by a downregulation in late AD pathology in AppNL-G-F mice, correlating with synaptic loss. To understand the consequences of pathophysiological SPPL2b dysregulation, we found that SPPL2b overexpression significantly increased APP cleavage, while genetic deletion reduced APP cleavage and Aβ production. Notably, postmortem AD brains showed higher levels of SPPL2b's BRI2 substrate compared to healthy control samples. These results strongly support the involvement of SPPL2b in AD pathology. The early Aβ-induced upregulation of SPPL2b may enhance Aβ production in a vicious cycle, further aggravating Aβ pathology. Therefore, SPPL2b emerges as a potential anti-Aβ drug target.
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Affiliation(s)
- Riccardo Maccioni
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, United States.
| | - Caterina Travisan
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; VIB-KU Leuven Center for Brain and Disease Research, Leuven 3001, Belgium.
| | - Jack Badman
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden.
| | - Stefania Zerial
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; Department of life science, University of Trieste, Trieste 34127, Italy.
| | - Annika Wagener
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, 69117 Germany.
| | - Yuniesky Andrade-Talavera
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden.
| | - Federico Picciau
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; Department of Biomedical Sciences, Cytomorphology, University of Cagliari, Cagliari 09042, Italy.
| | - Caterina Grassi
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; Department of Pharmacy and Biotechnology, University of Bologna, Bologna 40126, Italy.
| | - Gefei Chen
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge 141 52, Sweden.
| | - Laetitia Lemoine
- Department of Neurobiology, Care Sciences, and Society, Division of Clinical Geriatrics, Center for Alzheimer Research, Karolinska Institutet, Huddinge 141 52, Sweden.
| | - André Fisahn
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden.
| | - Richeng Jiang
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden; Department of Otolaryngology Head and Neck Surgery, The First Hospital of Jilin University, Changchun 130021, China.
| | - Regina Fluhrer
- Biochemistry and Molecular Biology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, 86159, Germany.
| | - Torben Mentrup
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden 01307, Germany.
| | - Bernd Schröder
- Institute of Physiological Chemistry, Technische Universität Dresden, Dresden 01307, Germany.
| | - Per Nilsson
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden.
| | - Simone Tambaro
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna 171 64, Sweden.
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2
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Bhembre N, Bonthron C, Opazo P. Synaptic Compensatory Plasticity in Alzheimer's Disease. J Neurosci 2023; 43:6833-6840. [PMID: 37821232 PMCID: PMC10573755 DOI: 10.1523/jneurosci.0379-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/28/2023] [Accepted: 07/06/2023] [Indexed: 10/13/2023] Open
Abstract
The loss of excitatory synapses is known to underlie the cognitive deficits in Alzheimer's disease (AD). Although much is known about the mechanisms underlying synaptic loss in AD, how neurons compensate for this loss and whether this provides cognitive benefits remain almost completely unexplored. In this review, we describe two potential compensatory mechanisms implemented following synaptic loss: the enlargement of the surviving neighboring synapses and the regeneration of synapses. Because dendritic spines, the postsynaptic site of excitatory synapses, are easily visualized using light microscopy, we focus on a range of microscopy approaches to monitor synaptic loss and compensation. Here, we stress the importance of longitudinal dendritic spine imaging, as opposed to fixed-tissue imaging, to gain insights into the temporal dynamics of dendritic spine compensation. We believe that understanding the molecular mechanisms behind these and other forms of synaptic compensation and regeneration will be critical for the development of therapeutics aiming at delaying the onset of cognitive deficits in AD.
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Affiliation(s)
- Nishita Bhembre
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Calum Bonthron
- UK Dementia Research Institute, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh Medical School, Edinburgh, EH16 4SB, United Kingdom
| | - Patricio Opazo
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
- UK Dementia Research Institute, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh Medical School, Edinburgh, EH16 4SB, United Kingdom
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3
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Selective plasticity of callosal neurons in the adult contralesional cortex following murine traumatic brain injury. Nat Commun 2022; 13:2659. [PMID: 35551446 PMCID: PMC9098892 DOI: 10.1038/s41467-022-29992-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/11/2022] [Indexed: 11/17/2022] Open
Abstract
Traumatic brain injury (TBI) results in deficits that are often followed by recovery. The contralesional cortex can contribute to this process but how distinct contralesional neurons and circuits respond to injury remains to be determined. To unravel adaptations in the contralesional cortex, we used chronic in vivo two-photon imaging. We observed a general decrease in spine density with concomitant changes in spine dynamics over time. With retrograde co-labeling techniques, we showed that callosal neurons are uniquely affected by and responsive to TBI. To elucidate circuit connectivity, we used monosynaptic rabies tracing, clearing techniques and histology. We demonstrate that contralesional callosal neurons adapt their input circuitry by strengthening ipsilateral connections from pre-connected areas. Finally, functional in vivo two-photon imaging demonstrates that the restoration of pre-synaptic circuitry parallels the restoration of callosal activity patterns. Taken together our study thus delineates how callosal neurons structurally and functionally adapt following a contralateral murine TBI. Which contralesional circuits adapt after traumatic brain injury (TBI) is unclear. Here the authors used in vivo imaging, retrograde labeling, rabies tracing, clearing and functional imaging to demonstrate that callosal neurons selectively adapt after TBI in mice.
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4
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Cortical axon sub-population maintains density, but not turnover, of en passant boutons in the aged APP/PS1 amyloidosis model. Neurobiol Aging 2022; 115:29-38. [DOI: 10.1016/j.neurobiolaging.2022.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/10/2022] [Accepted: 03/12/2022] [Indexed: 11/21/2022]
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5
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Long-term dynamics of aberrant neuronal activity in awake Alzheimer's disease transgenic mice. Commun Biol 2021; 4:1368. [PMID: 34876653 PMCID: PMC8651654 DOI: 10.1038/s42003-021-02884-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 11/11/2021] [Indexed: 01/07/2023] Open
Abstract
Alzheimer's disease (AD) is associated with aberrant neuronal activity, which is believed to critically determine disease symptoms. How these activity alterations emerge, how stable they are over time, and whether cellular activity dynamics are affected by the amyloid plaque pathology remains incompletely understood. We here repeatedly recorded the activity from identified neurons in cortex of awake APPPS1 transgenic mice over four weeks during the early phase of plaque deposition using in vivo two-photon calcium imaging. We found that aberrant activity during this stage largely persisted over the observation time. Novel highly active neurons slowly emerged from former intermediately active neurons. Furthermore, activity fluctuations were independent of plaque proximity, but aberrant activity was more likely to persist close to plaques. These results support the notion that neuronal network pathology observed in models of cerebral amyloidosis is the consequence of persistent single cell aberrant neuronal activity, a finding of potential diagnostic and therapeutic relevance for AD.
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6
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Sosulina L, Mittag M, Geis HR, Hoffmann K, Klyubin I, Qi Y, Steffen J, Friedrichs D, Henneberg N, Fuhrmann F, Justus D, Keppler K, Cuello AC, Rowan MJ, Fuhrmann M, Remy S. Hippocampal hyperactivity in a rat model of Alzheimer's disease. J Neurochem 2021; 157:2128-2144. [PMID: 33583024 DOI: 10.1111/jnc.15323] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 01/19/2021] [Accepted: 01/31/2021] [Indexed: 12/21/2022]
Abstract
Neuronal network dysfunction is a hallmark of Alzheimer's disease (AD). However, the underlying pathomechanisms remain unknown. We analyzed the hippocampal micronetwork in transgenic McGill-R-Thy1-APP rats (APPtg) at the beginning of extracellular amyloid beta (Aβ) deposition. We established two-photon Ca2+ -imaging in vivo in the hippocampus of rats and found hyperactivity of CA1 neurons. Patch-clamp recordings in brain slices in vitro revealed increased neuronal input resistance and prolonged action potential width in CA1 pyramidal neurons. We did neither observe changes in synaptic inhibition, nor in excitation. Our data support the view that increased intrinsic excitability of CA1 neurons may precede inhibitory dysfunction at an early stage of Aβ-deposition and disease progression.
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Affiliation(s)
- Liudmila Sosulina
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Department of Cellular Neuroscience, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Manuel Mittag
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Hans-Rüdiger Geis
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Kerstin Hoffmann
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Igor Klyubin
- Department of Pharmacology and Therapeutics, Trinity College, Dublin, Ireland
| | - Yingjie Qi
- Department of Pharmacology and Therapeutics, Trinity College, Dublin, Ireland
| | - Julia Steffen
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Detlef Friedrichs
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Niklas Henneberg
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Falko Fuhrmann
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Daniel Justus
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Kevin Keppler
- Light Microscopy Facility, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - A Claudio Cuello
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Michael J Rowan
- Department of Pharmacology and Therapeutics, Trinity College, Dublin, Ireland
| | - Martin Fuhrmann
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Stefan Remy
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Department of Cellular Neuroscience, Leibniz Institute for Neurobiology, Magdeburg, Germany
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7
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Jamjoom AAB, Rhodes J, Andrews PJD, Grant SGN. The synapse in traumatic brain injury. Brain 2021; 144:18-31. [PMID: 33186462 PMCID: PMC7880663 DOI: 10.1093/brain/awaa321] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/13/2022] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability worldwide and is a risk factor for dementia later in life. Research into the pathophysiology of TBI has focused on the impact of injury on the neuron. However, recent advances have shown that TBI has a major impact on synapse structure and function through a combination of the immediate mechanical insult and the ensuing secondary injury processes, leading to synapse loss. In this review, we highlight the role of the synapse in TBI pathophysiology with a focus on the confluence of multiple secondary injury processes including excitotoxicity, inflammation and oxidative stress. The primary insult triggers a cascade of events in each of these secondary processes and we discuss the complex interplay that occurs at the synapse. We also examine how the synapse is impacted by traumatic axonal injury and the role it may play in the spread of tau after TBI. We propose that astrocytes play a crucial role by mediating both synapse loss and recovery. Finally, we highlight recent developments in the field including synapse molecular imaging, fluid biomarkers and therapeutics. In particular, we discuss advances in our understanding of synapse diversity and suggest that the new technology of synaptome mapping may prove useful in identifying synapses that are vulnerable or resistant to TBI.
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Affiliation(s)
- Aimun A B Jamjoom
- Centre for Clinical Brain Sciences, Chancellor's Building, Edinburgh BioQuarter, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Jonathan Rhodes
- Anaesthesia, Critical Care and Pain Medicine, University of Edinburgh, Edinburgh EH16 4SA, UK
| | - Peter J D Andrews
- Anaesthesia, Critical Care and Pain Medicine, University of Edinburgh, Edinburgh EH16 4SA, UK
| | - Seth G N Grant
- Centre for Clinical Brain Sciences, Chancellor's Building, Edinburgh BioQuarter, University of Edinburgh, Edinburgh EH16 4SB, UK
- Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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8
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He P, Schulz P, Sierks MR. A conformation-specific antibody against oligomeric β-amyloid restores neuronal integrity in a mouse model of Alzheimer's disease. J Biol Chem 2021; 296:100241. [PMID: 33376140 PMCID: PMC7948963 DOI: 10.1074/jbc.ra120.015327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 12/03/2020] [Accepted: 12/29/2020] [Indexed: 11/06/2022] Open
Abstract
Conformationally distinct aggregates of the amyloid β (Aβ) peptide accumulate in brains of patients with Alzheimer's disease (AD), but the roles of the different aggregates in disease progression are not clear. We previously isolated two single-chain variable domain antibody fragments (scFvs), C6T and A4, that selectively bind different toxic conformational variants of oligomeric Aβ. Here, we utilize these scFvs to localize the presence of these Aβ variants in human AD brain and to demonstrate their potential as therapeutic agents for treating AD. Both A4 and C6T label oligomeric Aβ in extracellular amyloid plaques, whereas C6T also labels intracellular oligomeric Aβ in human AD brain tissue and in an AD mouse model. For therapeutic studies, the A4 and C6T scFvs were expressed in the AD mice by viral infection of liver cells. The scFvs were administered at 2 months of age, and mice sacrificed at 9 months. The scFvs contained a peptide tag to facilitate transport across the blood brain barrier. While treatment with C6T only slightly decreased Aβ deposits and plaque-associated inflammation, it restored neuronal integrity to WT levels, significantly promoted growth of new neurons, and impressively rescued survival rates to WT levels. Treatment with A4 on the other hand significantly decreased Aβ deposits but did not significantly decrease neuroinflammation or promote neuronal integrity, neurogenesis, or survival rate. These results suggest that the specific Aβ conformation targeted in therapeutic applications greatly affects the outcome, and the location of the targeted Aβ variants may also play a critical factor.
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Affiliation(s)
- Ping He
- Department of Chemical Engineering, Arizona State University, Tempe, Arizona, USA
| | - Philip Schulz
- Department of Chemical Engineering, Arizona State University, Tempe, Arizona, USA
| | - Michael R Sierks
- Department of Chemical Engineering, Arizona State University, Tempe, Arizona, USA.
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9
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Subramanian J, Savage JC, Tremblay MÈ. Synaptic Loss in Alzheimer's Disease: Mechanistic Insights Provided by Two-Photon in vivo Imaging of Transgenic Mouse Models. Front Cell Neurosci 2020; 14:592607. [PMID: 33408613 PMCID: PMC7780885 DOI: 10.3389/fncel.2020.592607] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 11/25/2020] [Indexed: 01/05/2023] Open
Abstract
Synapse loss is the strongest correlate for cognitive decline in Alzheimer's disease. The mechanisms underlying synapse loss have been extensively investigated using mouse models expressing genes with human familial Alzheimer's disease mutations. In this review, we summarize how multiphoton in vivo imaging has improved our understanding of synapse loss mechanisms associated with excessive amyloid in the living animal brain. We also discuss evidence obtained from these imaging studies for the role of cell-intrinsic calcium dyshomeostasis and cell-extrinsic activities of microglia, which are the immune cells of the brain, in mediating synapse loss.
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Affiliation(s)
- Jaichandar Subramanian
- Department of Pharmacology & Toxicology, University of Kansas, Lawrence, KS, United States
| | - Julie C Savage
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
| | - Marie-Ève Tremblay
- Neurology and Neurosurgery Department, McGill University, Montreal, QC, Canada.,Department of Molecular Medicine, Université Laval, Québec City, QC, Canada.,Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.,Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
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10
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Kartalou GI, Salgueiro-Pereira AR, Endres T, Lesnikova A, Casarotto P, Pousinha P, Delanoe K, Edelmann E, Castrén E, Gottmann K, Marie H, Lessmann V. Anti-Inflammatory Treatment with FTY720 Starting after Onset of Symptoms Reverses Synaptic Deficits in an AD Mouse Model. Int J Mol Sci 2020; 21:ijms21238957. [PMID: 33255764 PMCID: PMC7734581 DOI: 10.3390/ijms21238957] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/19/2020] [Accepted: 11/21/2020] [Indexed: 12/19/2022] Open
Abstract
Therapeutic approaches providing effective medication for Alzheimer's disease (AD) patients after disease onset are urgently needed. Previous studies in AD mouse models suggested that physical exercise or changed lifestyle can delay AD-related synaptic and memory dysfunctions when treatment started in juvenile animals long before onset of disease symptoms, while a pharmacological treatment that can reverse synaptic and memory deficits in AD mice was thus far not identified. Repurposing food and drug administration (FDA)-approved drugs for treatment of AD is a promising way to reduce the time to bring such medication into clinical practice. The sphingosine-1 phosphate analog fingolimod (FTY720) was approved recently for treatment of multiple sclerosis patients. Here, we addressed whether fingolimod rescues AD-related synaptic deficits and memory dysfunction in an amyloid precursor protein/presenilin-1 (APP/PS1) AD mouse model when medication starts after onset of symptoms (at five months). Male mice received intraperitoneal injections of fingolimod for one to two months starting at five to six months. This treatment rescued spine density as well as long-term potentiation in hippocampal cornu ammonis-1 (CA1) pyramidal neurons, that were both impaired in untreated APP/PS1 animals at six to seven months of age. Immunohistochemical analysis with markers of microgliosis (ionized calcium-binding adapter molecule 1; Iba1) and astrogliosis (glial fibrillary acid protein; GFAP) revealed that our fingolimod treatment regime strongly down regulated neuroinflammation in the hippocampus and neocortex of this AD model. These effects were accompanied by a moderate reduction of Aβ accumulation in hippocampus and neocortex. Our results suggest that fingolimod, when applied after onset of disease symptoms in an APP/PS1 mouse model, rescues synaptic pathology that is believed to underlie memory deficits in AD mice, and that this beneficial effect is mediated via anti-neuroinflammatory actions of the drug on microglia and astrocytes.
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Affiliation(s)
- Georgia-Ioanna Kartalou
- Institute of Physiology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (G.-I.K.); (T.E.); (E.E.)
- Institute of Neuro- and Sensory Physiology, Medical Faculty, Heinrich Heine University, 40225 Duesseldorf, Germany
| | - Ana Rita Salgueiro-Pereira
- Université Côte d’Azur, CNRS, IPMC, UMR7275, 06560 Valbonne, France; (A.R.S.-P.); (P.P.); (K.D.); (H.M.)
| | - Thomas Endres
- Institute of Physiology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (G.-I.K.); (T.E.); (E.E.)
| | - Angelina Lesnikova
- Neuroscience Center, HiLIFE, University of Helsinki, 00290 Helsinki, Finland; (A.L.); (P.C.); (E.C.)
| | - Plinio Casarotto
- Neuroscience Center, HiLIFE, University of Helsinki, 00290 Helsinki, Finland; (A.L.); (P.C.); (E.C.)
| | - Paula Pousinha
- Université Côte d’Azur, CNRS, IPMC, UMR7275, 06560 Valbonne, France; (A.R.S.-P.); (P.P.); (K.D.); (H.M.)
| | - Kevin Delanoe
- Université Côte d’Azur, CNRS, IPMC, UMR7275, 06560 Valbonne, France; (A.R.S.-P.); (P.P.); (K.D.); (H.M.)
| | - Elke Edelmann
- Institute of Physiology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (G.-I.K.); (T.E.); (E.E.)
| | - Eero Castrén
- Neuroscience Center, HiLIFE, University of Helsinki, 00290 Helsinki, Finland; (A.L.); (P.C.); (E.C.)
| | - Kurt Gottmann
- Institute of Neuro- and Sensory Physiology, Medical Faculty, Heinrich Heine University, 40225 Duesseldorf, Germany
- Correspondence: (K.G.); (V.L.)
| | - Hélène Marie
- Université Côte d’Azur, CNRS, IPMC, UMR7275, 06560 Valbonne, France; (A.R.S.-P.); (P.P.); (K.D.); (H.M.)
| | - Volkmar Lessmann
- Institute of Physiology, Medical Faculty, Otto-von-Guericke University, 39120 Magdeburg, Germany; (G.-I.K.); (T.E.); (E.E.)
- Center for Behavioral Brain Sciences (CBBS), 39120 Magdeburg, Germany
- Correspondence: (K.G.); (V.L.)
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11
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Golgi-Cox impregnation combined with fluorescence staining of amyloid plaques reveals local spine loss in an Alzheimer mouse model. J Neurosci Methods 2020; 341:108797. [PMID: 32479974 DOI: 10.1016/j.jneumeth.2020.108797] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 05/25/2020] [Accepted: 05/25/2020] [Indexed: 11/20/2022]
Abstract
BACKGROUND Spine loss is a hallmark of Alzheimer´s and other neurodegenerative diseases, and testing candidate therapeutic drugs needs quantitative analysis of dendritic spine densities. Golgi-Cox impregnation of neurons is a classical method to visualize dendritic spines in diseased brains. Importantly, at early disease stages spine loss occurs locally in the vicinity of amyloid plaques, and concomitant fluorescence labeling of amyloid plaques is required to detect local spine damage. NEW METHOD Because Golgi-Cox impregnation is done on unsectioned brains, whereas fluorescence staining is performed on sectioned material, the combination is technically challenging. We have now developed a novel combination of Golgi-Cox impregnation with methoxy-X04 fluorescence labeling of plaques that is performed on unsectioned brains. RESULTS We used this new combination method to quantify dendritic spine densities in mouse hippocampal CA1 pyramidal neurons. Comparison of neurons from wildtype and APP/PS1 mice revealed local spine loss in the vicinity of amyloid plaques in both male and female APP/PS1 mice. COMPARISON WITH EXISTING METHOD Golgi-Cox impregnation of neurons combined with methoxy-X04 staining of amyloid plaques is a highly reliable, easy-to-use method for permanent visualization of spines as compared to the technically more sophisticated and less stable fluorescence imaging of spines. CONCLUSION Our novel combination method will be highly useful for testing potential therapeutic drugs in Alzheimer mouse models.
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12
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Hrynchak MV, Rierola M, Golovyashkina N, Penazzi L, Pump WC, David B, Sündermann F, Brandt R, Bakota L. Chronic Presence of Oligomeric Aβ Differentially Modulates Spine Parameters in the Hippocampus and Cortex of Mice With Low APP Transgene Expression. Front Synaptic Neurosci 2020; 12:16. [PMID: 32390822 PMCID: PMC7194154 DOI: 10.3389/fnsyn.2020.00016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 03/25/2020] [Indexed: 01/06/2023] Open
Abstract
Alzheimer’s disease is regarded as a synaptopathy with a long presymptomatic phase. Soluble, oligomeric amyloid-β (Aβ) is thought to play a causative role in this disease, which eventually leads to cognitive decline. However, most animal studies have employed mice expressing high levels of the Aβ precursor protein (APP) transgene to drive pathology. Here, to understand how the principal neurons in different brain regions cope with moderate, chronically present levels of Aβ, we employed transgenic mice expressing equal levels of mouse and human APP carrying a combination of three familial AD (FAD)-linked mutations (Swedish, Dutch, and London), that develop plaques only in old age. We analyzed dendritic spine parameters in hippocampal and cortical brain regions after targeted expression of EGFP to allow high-resolution imaging, followed by algorithm-based evaluation of mice of both sexes from adolescence to old age. We report that Aβ species gradually accumulated throughout the life of APPSDL mice, but not the oligomeric forms, and that the amount of membrane-associated oligomers decreased at the onset of plaque formation. We observed an age-dependent loss of thin spines under most conditions as an indicator of a loss of synaptic plasticity in older mice. We further found that hippocampal pyramidal neurons respond to increased Aβ levels by lowering spine density and shifting spine morphology, which reached significance in the CA1 subfield. In contrast, the spine density in cortical pyramidal neurons of APPSDL mice was unchanged. We also observed an increase in the protein levels of PSD-95 and Arc in the hippocampus and cortex, respectively. Our data demonstrated that increased concentrations of Aβ have diverse effects on dendritic spines in the brain and suggest that hippocampal and cortical neurons have different adaptive and compensatory capacity during their lifetime. Our data also indicated that spine morphology differs between sexes in a region-specific manner.
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Affiliation(s)
- Mariya V Hrynchak
- Department of Neurobiology, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Marina Rierola
- Department of Neurobiology, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Nataliya Golovyashkina
- Department of Neurobiology, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Lorène Penazzi
- Department of Neurobiology, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Wiebke C Pump
- Department of Neurobiology, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Bastian David
- Department of Neurobiology, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Frederik Sündermann
- Department of Neurobiology, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Roland Brandt
- Department of Neurobiology, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany.,Center for Cellular Nanoanalytics, University of Osnabrück, Osnabrück, Germany.,Institute of Cognitive Science, University of Osnabrück, Osnabrück, Germany
| | - Lidia Bakota
- Department of Neurobiology, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
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13
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Vyas Y, Montgomery JM, Cheyne JE. Hippocampal Deficits in Amyloid-β-Related Rodent Models of Alzheimer's Disease. Front Neurosci 2020; 14:266. [PMID: 32317913 PMCID: PMC7154147 DOI: 10.3389/fnins.2020.00266] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/09/2020] [Indexed: 12/18/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease that is the most common cause of dementia. Symptoms of AD include memory loss, disorientation, mood and behavior changes, confusion, unfounded suspicions, and eventually, difficulty speaking, swallowing, and walking. These symptoms are caused by neuronal degeneration and cell loss that begins in the hippocampus, and later in disease progression spreading to the rest of the brain. While there are some medications that alleviate initial symptoms, there are currently no treatments that stop disease progression. Hippocampal deficits in amyloid-β-related rodent models of AD have revealed synaptic, behavioral and circuit-level defects. These changes in synaptic function, plasticity, neuronal excitability, brain connectivity, and excitation/inhibition imbalance all have profound effects on circuit function, which in turn could exacerbate disease progression. Despite, the wealth of studies on AD pathology we don't yet have a complete understanding of hippocampal deficits in AD. With the increasing development of in vivo recording techniques in awake and freely moving animals, future studies will extend our current knowledge of the mechanisms underpinning how hippocampal function is altered in AD, and aid in progression of treatment strategies that prevent and/or delay AD symptoms.
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Affiliation(s)
| | - Johanna M. Montgomery
- Department of Physiology, Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Juliette E. Cheyne
- Department of Physiology, Centre for Brain Research, University of Auckland, Auckland, New Zealand
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14
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Poppe L, Rué L, Timmers M, Lenaerts A, Storm A, Callaerts-Vegh Z, Courtand G, de Boer A, Smolders S, Van Damme P, Van Den Bosch L, D'Hooge R, De Strooper B, Robberecht W, Lemmens R. EphA4 loss improves social memory performance and alters dendritic spine morphology without changes in amyloid pathology in a mouse model of Alzheimer's disease. ALZHEIMERS RESEARCH & THERAPY 2019; 11:102. [PMID: 31831046 PMCID: PMC6909519 DOI: 10.1186/s13195-019-0554-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/08/2019] [Indexed: 12/24/2022]
Abstract
Background EphA4 is a receptor of the ephrin system regulating spine morphology and plasticity in the brain. These processes are pivotal in the pathophysiology of Alzheimer’s disease (AD), characterized by synapse dysfunction and loss, and the progressive loss of memory and other cognitive functions. Reduced EphA4 signaling has been shown to rescue beta-amyloid-induced dendritic spine loss and long-term potentiation (LTP) deficits in cultured hippocampal slices and primary hippocampal cultures. In this study, we investigated whether EphA4 ablation might preserve synapse function and ameliorate cognitive performance in the APPPS1 transgenic mouse model of AD. Methods A postnatal genetic ablation of EphA4 in the forebrain was established in the APPPS1 mouse model of AD, followed by a battery of cognitive tests at 9 months of age to investigate cognitive function upon EphA4 loss. A Golgi-Cox staining was used to explore alterations in dendritic spine density and morphology in the CA1 region of the hippocampus. Results Upon EphA4 loss in APPPS1 mice, we observed improved social memory in the preference for social novelty test without affecting other cognitive functions. Dendritic spine analysis revealed altered synapse morphology as characterized by increased dendritic spine length and head width. These modifications were independent of hippocampal plaque load and beta-amyloid peptide levels since these were similar in mice with normal versus reduced levels of EphA4. Conclusion Loss of EphA4 improved social memory in a mouse model of Alzheimer’s disease in association with alterations in spine morphology.
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Affiliation(s)
- Lindsay Poppe
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Laura Rué
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Mieke Timmers
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Annette Lenaerts
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Annet Storm
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Zsuzsanna Callaerts-Vegh
- Laboratory of Biological Psychology, Faculty of Psychology and Educational Sciences, KU Leuven - University of Leuven, Leuven, Belgium.,mINT Animal Behavior Core Facility, Faculty of Psychology, KU Leuven, Leuven, Belgium
| | - Gilles Courtand
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, Unité Mixte de Recherche 5287, Centre National de la Recherche Scientifique, Université de Bordeaux, 33076, Bordeaux, France
| | - Antina de Boer
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Silke Smolders
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Philip Van Damme
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Herestraat 49, B-3000, Leuven, Belgium
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium
| | - Rudi D'Hooge
- Laboratory of Biological Psychology, Faculty of Psychology and Educational Sciences, KU Leuven - University of Leuven, Leuven, Belgium
| | - Bart De Strooper
- VIB Center for Brain and Disease Research, Leuven, Belgium.,Department of Neurosciences, Katholieke Universiteit Leuven, Leuven, Belgium.,UK Dementia Research Institute at University College London, London, UK
| | - Wim Robberecht
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium.,Department of Neurology, University Hospitals Leuven, Herestraat 49, B-3000, Leuven, Belgium
| | - Robin Lemmens
- Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), KU Leuven - University of Leuven, Leuven, Belgium. .,Laboratory of Neurobiology, Center for Brain and Disease Research, VIB, Leuven, Belgium. .,Department of Neurology, University Hospitals Leuven, Herestraat 49, B-3000, Leuven, Belgium.
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15
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Imbalance in the response of pre- and post-synaptic components to amyloidopathy. Sci Rep 2019; 9:14837. [PMID: 31619689 PMCID: PMC6795896 DOI: 10.1038/s41598-019-50781-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 09/12/2019] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD)-associated synaptic dysfunction drives the progression of pathology from its earliest stages. Amyloid β (Aβ) species, both soluble and in plaque deposits, have been causally related to the progressive, structural and functional impairments observed in AD. It is, however, still unclear how Aβ plaques develop over time and how they progressively affect local synapse density and turnover. Here we observed, in a mouse model of AD, that Aβ plaques grow faster in the earlier stages of the disease and if their initial area is >500 µm2; this may be due to deposition occurring in the outer regions of the plaque, the plaque cloud. In addition, synaptic turnover is higher in the presence of amyloid pathology and this is paralleled by a reduction in pre- but not post-synaptic densities. Plaque proximity does not appear to have an impact on synaptic dynamics. These observations indicate an imbalance in the response of the pre- and post-synaptic terminals and that therapeutics, alongside targeting the underlying pathology, need to address changes in synapse dynamics.
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16
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Disruption of NOTCH signaling by a small molecule inhibitor of the transcription factor RBPJ. Sci Rep 2019; 9:10811. [PMID: 31346210 PMCID: PMC6658660 DOI: 10.1038/s41598-019-46948-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 07/03/2019] [Indexed: 01/08/2023] Open
Abstract
NOTCH plays a pivotal role during normal development and in congenital disorders and cancer. γ-secretase inhibitors are commonly used to probe NOTCH function, but also block processing of numerous other proteins. We discovered a new class of small molecule inhibitor that disrupts the interaction between NOTCH and RBPJ, which is the main transcriptional effector of NOTCH signaling. RBPJ Inhibitor-1 (RIN1) also blocked the functional interaction of RBPJ with SHARP, a scaffold protein that forms a transcriptional repressor complex with RBPJ in the absence of NOTCH signaling. RIN1 induced changes in gene expression that resembled siRNA silencing of RBPJ rather than inhibition at the level of NOTCH itself. Consistent with disruption of NOTCH signaling, RIN1 inhibited the proliferation of hematologic cancer cell lines and promoted skeletal muscle differentiation from C2C12 myoblasts. Thus, RIN1 inhibits RBPJ in its repressing and activating contexts, and can be exploited for chemical biology and therapeutic applications.
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17
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Bispecific Antibody Fragment Targeting APP and Inducing α-Site Cleavage Restores Neuronal Health in an Alzheimer's Mouse Model. Mol Neurobiol 2019; 56:7420-7432. [PMID: 31041656 DOI: 10.1007/s12035-019-1597-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 04/02/2019] [Indexed: 12/14/2022]
Abstract
The amyloid β (Aβ) peptide, correlated with development of Alzheimer's disease (AD), is produced by sequential proteolytic cleavage of the amyloid precursor protein (APP) by β- and γ-secretases. Alternative proteolytic cleavage of APP by α-secretase prevents formation of Aβ peptide and produces a neuroprotective protein, a soluble fragment of APPα (sAPPα). We previously generated a single-chain variable domain antibody fragment (scFv) that binds APP at the β-secretase cleavage site and blocks cleavage of APP (iBsec1), and a second scFv which has been engineered to have α-secretase-like activity that increases α-secretase cleavage of APP (Asec1a) and showed that a bispecific antibody (Diab) combining both iBsec1 and Asec1a constructs protects mammalian cells from oxidative stress. Here, we show that the diabody is an effective therapeutic agent in a mouse model of AD. An apolipoprotein B (ApoB) binding domain peptide was genetically added to the diabody to facilitate transfer across the blood-brain barrier, and a recombinant human adeno-associated virus 2/8 (rAAV2/8) was used as a vector to express the gene constructs in a APP/PS1 mouse model of AD. The diabody increased levels of sAPPα, decreased Aβ deposits and levels of oligomeric Aβ, increased neuronal health as indicated by MAP2 and synaptophysin staining, increased hippocampal neurogenesis, and most importantly dramatically increased survival rates compared with untreated mice or mice treated only with the β-secretase inhibitor. These results indicate that altering APP processing to inhibit β-site activity while simultaneously promoting α-secretase processing provides substantially increased neuronal benefits compared with inhibition of β-secretase processing alone and represents a promising new therapeutic approach for treating AD.
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18
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Overk C, Masliah E. Dale Schenk One Year Anniversary: Fighting to Preserve the Memories. J Alzheimers Dis 2019; 62:1-13. [PMID: 29439357 DOI: 10.3233/jad-171071] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
It has been a year since we lost Dale Schenk on September 30, 2016. Dale's visionary work resulted in the remarkable discovery in 1999 that an experimental amyloid-β (Aβ) vaccine reduced the neurodegeneration in a transgenic model of Alzheimer's disease (AD). Following Dale's seminal work, several active and passive immunotherapies have since been developed and tested in the clinic for AD, Parkinson's disease (PD), and other neurodegenerative disorders. Here we provide a brief overview of the current state of development of immunotherapy for AD, PD, and other neurodegenerative disorders in the context of this anniversary. The next steps in the development of immunotherapies will require combinatorial approaches mixing antibodies against various targets (e.g., Aβ, α-syn, Tau, and TDP43) with small molecules that block toxicity, aggregation, inflammation, and promote cell survival.
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Affiliation(s)
- Cassia Overk
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Eliezer Masliah
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA.,Division of Neurosciences and Molecular Neuropathology Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
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19
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Ziegler-Waldkirch S, Meyer-Luehmann M. The Role of Glial Cells and Synapse Loss in Mouse Models of Alzheimer's Disease. Front Cell Neurosci 2018; 12:473. [PMID: 30618627 PMCID: PMC6297249 DOI: 10.3389/fncel.2018.00473] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 11/20/2018] [Indexed: 11/13/2022] Open
Abstract
Synapse loss has detrimental effects on cellular communication, leading to network disruptions within the central nervous system (CNS) such as in Alzheimer’s disease (AD). AD is characterized by a progressive decline of memory function, cognition, neuronal and synapse loss. The two main neuropathological hallmarks are amyloid-β (Aβ) plaques and neurofibrillary tangles. In the brain of AD patients and in mouse models of AD several morphological and functional changes, such as microgliosis and astrogliosis around Aβ plaques, as well as dendritic and synaptic alterations, are associated with these lesions. In this review article, we will summarize the current literature on synapse loss in mouse models of AD and discuss current and prospective treatments for AD.
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Affiliation(s)
- Stephanie Ziegler-Waldkirch
- Department of Neurology, Medical Center-University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Melanie Meyer-Luehmann
- Department of Neurology, Medical Center-University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
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20
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Heiss JK, Barrett J, Yu Z, Haas LT, Kostylev MA, Strittmatter SM. Early Activation of Experience-Independent Dendritic Spine Turnover in a Mouse Model of Alzheimer's Disease. Cereb Cortex 2018; 27:3660-3674. [PMID: 27365298 DOI: 10.1093/cercor/bhw188] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Synaptic loss is critical in Alzheimer's disease (AD), but the dynamics of synapse turnover are poorly defined. We imaged dendritic spines in transgenic APPswe/PSen1∆E9 (APP/PS1) cerebral cortex. Dendritic spine turnover is increased far from plaque in aged APP/PS1 mice, and in young APP/PS1 mice prior to plaque formation. Dysregulation occurs in the presence of soluble Aβ oligomer and requires cellular prion protein (PrPC). APP/PS1 mice lack responsiveness of spine turnover to sensory stimulation. Critically, enhanced spine turnover is coupled with the loss of persistent spines starting early and continuing with age. To evaluate mechanisms of experience-independent supranormal spine turnover, we analyzed the transcriptome of young APP/PS1 mouse brain when turnover is altered but synapse density and memory are normal, and plaque and inflammation are absent. Early PrPC-dependent expression changes occur in synaptic and lipid-metabolizing genes. Thus, pathologic synaptic dysregulation underlying AD begins at a young age prior to Aβ plaque.
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Affiliation(s)
- Jacqueline K Heiss
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA.,Department of Pharmacology, Yale University School of Medicine, New Haven CT 06520, USA
| | - Joshua Barrett
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Zizi Yu
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Laura T Haas
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Mikhail A Kostylev
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Stephen M Strittmatter
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA.,Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
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21
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EPBscore: a Novel Method for Computer-Assisted Analysis of Axonal Structure and Dynamics. Neuroinformatics 2016; 14:121-7. [PMID: 26163988 DOI: 10.1007/s12021-015-9274-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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22
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Schmid LC, Mittag M, Poll S, Steffen J, Wagner J, Geis HR, Schwarz I, Schmidt B, Schwarz MK, Remy S, Fuhrmann M. Dysfunction of Somatostatin-Positive Interneurons Associated with Memory Deficits in an Alzheimer's Disease Model. Neuron 2016; 92:114-125. [PMID: 27641495 DOI: 10.1016/j.neuron.2016.08.034] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 04/11/2016] [Accepted: 08/19/2016] [Indexed: 02/09/2023]
Abstract
Alzheimer's disease (AD) is characterized by cognitive decline and neuronal network dysfunction, but the underlying mechanisms remain unknown. In the hippocampus, microcircuit activity during learning and memory processes is tightly controlled by O-LM interneurons. Here, we investigated the effect of beta-amyloidosis on O-LM interneuron structural and functional connectivity, combining two-photon in vivo imaging of synaptic morphology, awake Ca2+ imaging, and retrograde mono-transsynaptic rabies tracing. We find severely impaired synaptic rewiring that occurs on the O-LM interneuron input and output level in a mouse model of AD. Synaptic rewiring that occurs upon fear learning on O-LM interneuron input level is affected in mice with AD-like pathology. This process requires the release of acetylcholine from septo-hippocampal projections. We identify decreased cholinergic action on O-LM interneurons in APP/PS1 mice as a key pathomechanism that contributes to memory impairment in a mouse model, with potential relevance for human AD.
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Affiliation(s)
- Lena C Schmid
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Manuel Mittag
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Stefanie Poll
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Julia Steffen
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Jens Wagner
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Hans-Rüdiger Geis
- Neuronal Networks Group, German Center for Neurodegenerative Diseases, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Inna Schwarz
- Functional Neuroconnectomics Group, Department of Epileptology, Medical School, University of Bonn, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany
| | - Boris Schmidt
- Clemens-Schöpf-Institute, Technical University of Darmstadt, 64289 Darmstadt, Germany
| | - Martin K Schwarz
- Functional Neuroconnectomics Group, Department of Epileptology, Medical School, University of Bonn, Sigmund-Freud-Str. 25, D-53105 Bonn, Germany
| | - Stefan Remy
- Neuronal Networks Group, German Center for Neurodegenerative Diseases, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Martin Fuhrmann
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases, Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
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23
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Fukumori A, Steiner H. Substrate recruitment of γ-secretase and mechanism of clinical presenilin mutations revealed by photoaffinity mapping. EMBO J 2016; 35:1628-43. [PMID: 27220847 DOI: 10.15252/embj.201694151] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/26/2016] [Indexed: 12/27/2022] Open
Abstract
Intramembrane proteases execute fundamental biological processes ranging from crucial signaling events to general membrane proteostasis. Despite the availability of structural information on these proteases, it remains unclear how these enzymes bind and recruit substrates, particularly for the Alzheimer's disease-associated γ-secretase. Systematically scanning amyloid precursor protein substrates containing a genetically inserted photocrosslinkable amino acid for binding to γ-secretase allowed us to identify residues contacting the protease. These were primarily found in the transmembrane cleavage domain of the substrate and were also present in the extramembranous domains. The N-terminal fragment of the catalytic subunit presenilin was determined as principal substrate-binding site. Clinical presenilin mutations altered substrate binding in the active site region, implying a pathogenic mechanism for familial Alzheimer's disease. Remarkably, PEN-2 was identified besides nicastrin as additional substrate-binding subunit. Probing proteolysis of crosslinked substrates revealed a mechanistic model of how these subunits interact to mediate a stepwise transfer of bound substrate to the catalytic site. We propose that sequential binding steps might be common for intramembrane proteases to sample and select cognate substrates for catalysis.
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Affiliation(s)
- Akio Fukumori
- Biomedical Center (BMC), Metabolic Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Harald Steiner
- Biomedical Center (BMC), Metabolic Biochemistry, Ludwig-Maximilians-University Munich, Munich, Germany German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
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24
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Selective Persistence of Sensorimotor Mismatch Signals in Visual Cortex of Behaving Alzheimer’s Disease Mice. Curr Biol 2016; 26:956-64. [DOI: 10.1016/j.cub.2016.01.070] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 12/23/2015] [Accepted: 01/28/2016] [Indexed: 11/20/2022]
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25
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Brendel M, Jaworska A, Herms J, Trambauer J, Rötzer C, Gildehaus FJ, Carlsen J, Cumming P, Bylund J, Luebbers T, Bartenstein P, Steiner H, Haass C, Baumann K, Rominger A. Amyloid-PET predicts inhibition of de novo plaque formation upon chronic γ-secretase modulator treatment. Mol Psychiatry 2015; 20:1179-87. [PMID: 26055427 PMCID: PMC4759098 DOI: 10.1038/mp.2015.74] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 03/31/2015] [Accepted: 04/13/2015] [Indexed: 01/18/2023]
Abstract
In a positron-emission tomography (PET) study with the β-amyloid (Aβ) tracer [(18)F]-florbetaben, we previously showed that Aβ deposition in transgenic mice expressing Swedish mutant APP (APP-Swe) mice can be tracked in vivo. γ-Secretase modulators (GSMs) are promising therapeutic agents by reducing generation of the aggregation prone Aβ42 species without blocking general γ-secretase activity. We now aimed to investigate the effects of a novel GSM [8-(4-Fluoro-phenyl)-[1,2,4]triazolo[1,5-a]pyridin-2-yl]-[1-(3-methyl-[1,2,4]thiadiazol-5-yl)-piperidin-4-yl]-amine (RO5506284) displaying high potency in vitro and in vivo on amyloid plaque burden and used longitudinal Aβ-microPET to trace individual animals. Female transgenic (TG) APP-Swe mice aged 12 months (m) were assigned to vehicle (TG-VEH, n=12) and treatment groups (TG-GSM, n=12), which received daily RO5506284 (30 mg kg(-1)) treatment for 6 months. A total of 131 Aβ-PET recordings were acquired at baseline (12 months), follow-up 1 (16 months) and follow-up 2 (18 months, termination scan), whereupon histological and biochemical analyses of Aβ were performed. We analyzed the PET data as VOI-based cortical standard-uptake-value ratios (SUVR), using cerebellum as reference region. Individual plaque load assessed by PET remained nearly constant in the TG-GSM group during 6 months of RO5506284 treatment, whereas it increased progressively in the TG-VEH group. Baseline SUVR in TG-GSM mice correlated with Δ%-SUVR, indicating individual response prediction. Insoluble Aβ42 was reduced by 56% in the TG-GSM versus the TG-VEH group relative to the individual baseline plaque load estimates. Furthermore, plaque size histograms showed differing distribution between groups of TG mice, with fewer small plaques in TG-GSM animals. Taken together, in the first Aβ-PET study monitoring prolonged treatment with a potent GSM in an AD mouse model, we found clear attenuation of de novo amyloidogenesis. Moreover, longitudinal PET allows non-invasive assessment of individual plaque-load kinetics, thereby accommodating inter-animal variations.
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Affiliation(s)
- M Brendel
- Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - A Jaworska
- DZNE—German Center for Neurodegenerative Diseases, Munich, Germany,Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - J Herms
- DZNE—German Center for Neurodegenerative Diseases, Munich, Germany,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - J Trambauer
- Biomedical Center (BMC), Ludwig-Maximilians-University of Munich, Munich, Germany
| | - C Rötzer
- Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - F-J Gildehaus
- Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - J Carlsen
- Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - P Cumming
- Department of Psychiatry, University of Oslo, Oslo, Norway
| | - J Bylund
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - T Luebbers
- Roche Pharma Research and Early Development, Small Molecule Research, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - P Bartenstein
- Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - H Steiner
- DZNE—German Center for Neurodegenerative Diseases, Munich, Germany,Biomedical Center (BMC), Ludwig-Maximilians-University of Munich, Munich, Germany
| | - C Haass
- DZNE—German Center for Neurodegenerative Diseases, Munich, Germany,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany,Biomedical Center (BMC), Ludwig-Maximilians-University of Munich, Munich, Germany
| | - K Baumann
- Roche Pharma Research and Early Development, Neuroscience Discovery, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - A Rominger
- Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany,Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Marchioninistr. 15, Munich 81377, Germany. E-mail:
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