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Nikolaev A, McLaughlin T, O'Leary DDM, Tessier-Lavigne M. Retraction Note: APP binds DR6 to trigger axon pruning and neuron death via distinct caspases. Nature 2024; 625:204. [PMID: 38110576 PMCID: PMC10872530 DOI: 10.1038/s41586-023-06943-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Affiliation(s)
- Anatoly Nikolaev
- Division of Research, Genentech, Inc., 1 DNA Way, South San Francisco, California, 94080, USA
| | - Todd McLaughlin
- Molecular Neurobiology Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, California, 92037, USA
| | - Dennis D M O'Leary
- Molecular Neurobiology Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, California, 92037, USA
| | - Marc Tessier-Lavigne
- Division of Research, Genentech, Inc., 1 DNA Way, South San Francisco, California, 94080, USA.
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Chau DDL, Ng LLH, Zhai Y, Lau KF. Amyloid precursor protein and its interacting proteins in neurodevelopment. Biochem Soc Trans 2023; 51:1647-1659. [PMID: 37387352 PMCID: PMC10629809 DOI: 10.1042/bst20221527] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
Amyloid precursor protein (APP) is a key molecule in the pathogenesis of Alzheimer's disease (AD) as the pathogenic amyloid-β peptide is derived from it. Two closely related APP family proteins (APPs) have also been identified in mammals. Current knowledge, including genetic analyses of gain- and loss-of-function mutants, highlights the importance of APPs in various physiological functions. Notably, APPs consist of multiple extracellular and intracellular protein-binding regions/domains. Protein-protein interactions are crucial for many cellular processes. In past decades, many APPs interactors have been identified which assist the revelation of the putative roles of APPs. Importantly, some of these interactors have been shown to influence several APPs-mediated neuronal processes which are found defective in AD and other neurodegenerative disorders. Studying APPs-interactor complexes would not only advance our understanding of the physiological roles of APPs but also provide further insights into the association of these processes to neurodegeneration, which may lead to the development of novel therapies. In this mini-review, we summarize the roles of APPs-interactor complexes in neurodevelopmental processes including neurogenesis, neurite outgrowth, axonal guidance and synaptogenesis.
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Affiliation(s)
- Dennis Dik-Long Chau
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Laura Lok-Haang Ng
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Yuqi Zhai
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Kwok-Fai Lau
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Hong Kong SAR, China
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Huang Z. A Function of Amyloid-β in Mediating Activity-Dependent Axon/Synapse Competition May Unify Its Roles in Brain Physiology and Pathology. J Alzheimers Dis 2023; 92:29-57. [PMID: 36710681 PMCID: PMC10023438 DOI: 10.3233/jad-221042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Amyloid-β protein precursor (AβPP) gives rise to amyloid-β (Aβ), a peptide at the center of Alzheimer's disease (AD). AβPP, however, is also an ancient molecule dating back in evolution to some of the earliest forms of metazoans. This suggests a possible ancestral function that may have been obscured by those that evolve later. Based on literature from the functions of Aβ/AβPP in nervous system development, plasticity, and disease, to those of anti-microbial peptides (AMPs) in bacterial competition as well as mechanisms of cell competition uncovered first by Drosophila genetics, I propose that Aβ/AβPP may be part of an ancient mechanism employed in cell competition, which is subsequently co-opted during evolution for the regulation of activity-dependent neural circuit development and plasticity. This hypothesis is supported by foremost the high similarities of Aβ to AMPs, both of which possess unique, opposite (i.e., trophic versus toxic) activities as monomers and oligomers. A large body of data further suggests that the different Aβ oligomeric isoforms may serve as the protective and punishment signals long predicted to mediate activity-dependent axonal/synaptic competition in the developing nervous system and that the imbalance in their opposite regulation of innate immune and glial cells in the brain may ultimately underpin AD pathogenesis. This hypothesis can not only explain the diverse roles observed of Aβ and AβPP family molecules, but also provide a conceptual framework that can unify current hypotheses on AD. Furthermore, it may explain major clinical observations not accounted for and identify approaches for overcoming shortfalls in AD animal modeling.
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Affiliation(s)
- Zhen Huang
- Departments of Neuroscience and Neurology, University of Wisconsin-Madison, Madison, WI, USA
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4
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de León A, Gibon J, Barker PA. APP Genetic Deficiency Alters Intracellular Ca 2+ Homeostasis and Delays Axonal Degeneration in Dorsal Root Ganglion Sensory Neurons. J Neurosci 2022; 42:6680-6691. [PMID: 35882556 PMCID: PMC9436018 DOI: 10.1523/jneurosci.0162-22.2022] [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: 01/20/2022] [Revised: 06/08/2022] [Accepted: 07/11/2022] [Indexed: 11/21/2022] Open
Abstract
The activation of self-destructive cellular programs helps sculpt the nervous system during development, but the molecular mechanisms used are not fully understood. Prior studies have investigated the role of the APP in the developmental degeneration of sensory neurons with contradictory results. In this work, we sought to elucidate the impact of APP deletion in the development of the sensory nervous system in vivo and in vitro. Our in vivo data show an increase in the number of sciatic nerve axons in adult male and female APP-null mice, consistent with the hypothesis that APP plays a pro-degenerative role in the development of peripheral axons. In vitro, we show that genetic deletion of APP delays axonal degeneration triggered by nerve growth factor deprivation, indicating that APP does play a pro-degenerative role. Interestingly, APP depletion does not affect caspase-3 levels but significantly attenuates the rise of axoplasmic Ca2+ that occurs during degeneration. We examined intracellular Ca2+ mechanisms that could be involved and found that APP-null DRG neurons had increased Ca2+ levels within the endoplasmic reticulum and enhanced store-operated Ca2+ entry. We also observed that DRG axons lacking APP have more mitochondria than their WT counterparts, but these display a lower mitochondrial membrane potential. Finally, we present evidence that APP deficiency causes an increase in mitochondrial Ca2+ buffering capacity. Our results support the hypothesis that APP plays a pro-degenerative role in the developmental degeneration of DRG sensory neurons, and unveil the importance of APP in the regulation of calcium signaling in sensory neurons.SIGNIFICANCE STATEMENT The nervous system goes through a phase of pruning and programmed neuronal cell death during development to reach maturity. In such context, the role played by the APP in the peripheral nervous system has been controversial, ranging from pro-survival to pro-degenerative. Here we present evidence in vivo and in vitro supporting the pro-degenerative role of APP, demonstrating the ability of APP to alter intracellular Ca2+ homeostasis and mitochondria, critical players of programmed cell death. This work provides a better understanding of the physiological function of APP and its implication in developmental neuronal death in the nervous system.
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Affiliation(s)
- Andrés de León
- University of British Columbia Okanagan, Kelowna, British Columbia V1V 1V7, Canada
| | - Julien Gibon
- University of British Columbia Okanagan, Kelowna, British Columbia V1V 1V7, Canada
| | - Philip A Barker
- University of British Columbia Okanagan, Kelowna, British Columbia V1V 1V7, Canada
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William CM, Stern MA, Pei X, Saqran L, Ramani M, Frosch MP, Hyman BT. Impairment of visual cortical plasticity by amyloid-beta species. Neurobiol Dis 2021; 154:105344. [PMID: 33766652 DOI: 10.1016/j.nbd.2021.105344] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 03/06/2021] [Accepted: 03/19/2021] [Indexed: 10/21/2022] Open
Abstract
INTRODUCTION A variety of transgenic and knock-in mice that express mutant alleles of Amyloid precursor protein (APP) have been used to model the effects of amyloid-beta (Aβ) on circuit function in Alzheimer's disease (AD); however phenotypes described in these mice may be affected by expression of mutant APP or proteolytic cleavage products independent of Aβ. In addition, the effects of mutant APP expression are attributed to elevated expression of the amyloidogenic, 42-amino acid-long species of Aβ (Aβ42) associated with amyloid plaque accumulation in AD, though elevated concentrations of Aβ40, an Aβ species produced with normal synaptic activity, may also affect neural function. METHODS To explore the effects of elevated expression of Aβ on synaptic function in vivo, we assessed visual system plasticity in transgenic mice that express and secrete Aβ throughout the brain in the absence of APP overexpression. Transgenic mice that express either Aβ40 or Aβ42 were assayed for their ability to appropriately demonstrate ocular dominance plasticity following monocular deprivation. RESULTS Using two complementary approaches to measure the plastic response to monocular deprivation, we find that male and female mice that express either 40- or 42-amino acid-long Aβ species demonstrate a plasticity defect comparable to that elicited in transgenic mice that express mutant alleles of APP and Presenilin 1 (APP/PS1 mice). CONCLUSIONS These data support the hypothesis that mutant APP-driven plasticity impairment in mouse models of AD is mediated by production and accumulation of Aβ. Moreover, these findings suggest that soluble species of Aβ are capable of modulating synaptic plasticity, likely independent of any aggregation. These findings may have implications for the role of soluble species of Aβ in both development and disease settings.
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Affiliation(s)
- Christopher M William
- New York University Grossman School of Medicine, Department of Pathology, 550 First Avenue, New York, NY 10016, United States.
| | - Matthew A Stern
- MassGeneral Institute for Neurodegenerative Disease, Neurology, Massachusetts General Hospital, 114 16th St., Charlestown, MA 02129, United States.
| | - Xuewei Pei
- New York University Grossman School of Medicine, Department of Pathology, 550 First Avenue, New York, NY 10016, United States
| | - Lubna Saqran
- MassGeneral Institute for Neurodegenerative Disease, Neurology, Massachusetts General Hospital, 114 16th St., Charlestown, MA 02129, United States
| | - Margish Ramani
- New York University Grossman School of Medicine, Department of Pathology, 550 First Avenue, New York, NY 10016, United States.
| | - Matthew P Frosch
- Neuropathology Service, Massachusetts General Hospital, 114 16th St., Charlestown, MA 02129, United States; MassGeneral Institute for Neurodegenerative Disease, Neurology, Massachusetts General Hospital, 114 16th St., Charlestown, MA 02129, United States.
| | - Bradley T Hyman
- MassGeneral Institute for Neurodegenerative Disease, Neurology, Massachusetts General Hospital, 114 16th St., Charlestown, MA 02129, United States.
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Mishra V, Re DB, Le Verche V, Alvarez MJ, Vasciaveo A, Jacquier A, Doulias PT, Greco TM, Nizzardo M, Papadimitriou D, Nagata T, Rinchetti P, Perez-Torres EJ, Politi KA, Ikiz B, Clare K, Than ME, Corti S, Ischiropoulos H, Lotti F, Califano A, Przedborski S. Systematic elucidation of neuron-astrocyte interaction in models of amyotrophic lateral sclerosis using multi-modal integrated bioinformatics workflow. Nat Commun 2020; 11:5579. [PMID: 33149111 PMCID: PMC7642391 DOI: 10.1038/s41467-020-19177-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/02/2020] [Indexed: 12/31/2022] Open
Abstract
Cell-to-cell communications are critical determinants of pathophysiological phenotypes, but methodologies for their systematic elucidation are lacking. Herein, we propose an approach for the Systematic Elucidation and Assessment of Regulatory Cell-to-cell Interaction Networks (SEARCHIN) to identify ligand-mediated interactions between distinct cellular compartments. To test this approach, we selected a model of amyotrophic lateral sclerosis (ALS), in which astrocytes expressing mutant superoxide dismutase-1 (mutSOD1) kill wild-type motor neurons (MNs) by an unknown mechanism. Our integrative analysis that combines proteomics and regulatory network analysis infers the interaction between astrocyte-released amyloid precursor protein (APP) and death receptor-6 (DR6) on MNs as the top predicted ligand-receptor pair. The inferred deleterious role of APP and DR6 is confirmed in vitro in models of ALS. Moreover, the DR6 knockdown in MNs of transgenic mutSOD1 mice attenuates the ALS-like phenotype. Our results support the usefulness of integrative, systems biology approach to gain insights into complex neurobiological disease processes as in ALS and posit that the proposed methodology is not restricted to this biological context and could be used in a variety of other non-cell-autonomous communication mechanisms.
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Affiliation(s)
- Vartika Mishra
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
- Spark Therapeutics, 3737 Market Street, Philadelphia, PA, 19104, USA
| | - Diane B Re
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
- Department of Environmental Health Sciences, Columbia University, New York, NY, 10032, USA
| | - Virginia Le Verche
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
- Center for Gene Therapy, City of Hope, 1500 E. Duarte Road, Duarte, CA, 91010, USA
| | - Mariano J Alvarez
- Department of Systems Biology, Columbia University, New York, NY, 10032, USA
- DarwinHealth Inc., New York, NY, 10032, USA
| | - Alessandro Vasciaveo
- Department of Systems Biology, Columbia University, New York, NY, 10032, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA
| | - Arnaud Jacquier
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
- Institut NeuroMyoGène, CNRS UMR 5310 - INSERM U1217 - Université de Lyon - Université Claude Bernard Lyon 1, Lyon, France
| | - Paschalis-Tomas Doulias
- Department of Pediatrics, Children's Hospital of Philadelphia Research Institute and the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Todd M Greco
- Department of Pediatrics, Children's Hospital of Philadelphia Research Institute and the University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Molecular Biology, Princeton University, Princeton, USA
| | - Monica Nizzardo
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
- Dino Ferrari Center, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, 20122, Italy
| | - Dimitra Papadimitriou
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
- Henry Dunant Hospital, BRFAA, Athens, Greece
| | - Tetsuya Nagata
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
- Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Paola Rinchetti
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
- Dino Ferrari Center, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, 20122, Italy
| | - Eduardo J Perez-Torres
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
| | - Kristin A Politi
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
| | - Burcin Ikiz
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
| | - Kevin Clare
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
- New York Medical College, Valhalla, NY, 10595, USA
| | - Manuel E Than
- Protein Crystallography Group, Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Beutenbergstr. 11, 07745, Jena, Germany
| | - Stefania Corti
- Dino Ferrari Center, Department of Pathophysiology and Transplantation, University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, 20122, Italy
| | - Harry Ischiropoulos
- Department of Pediatrics, Children's Hospital of Philadelphia Research Institute and the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Francesco Lotti
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA
| | - Andrea Califano
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA.
- Department of Systems Biology, Columbia University, New York, NY, 10032, USA.
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA.
- J.P. Sulzberger Columbia Genome Center, Columbia University, New York, NY, USA.
- Department of Biomedical Informatics, Columbia University, New York, NY, USA.
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
| | - Serge Przedborski
- Departments of Pathology and Cell Biology, Columbia University, New York, NY, 10032, USA.
- Center for Motor Neuron Biology and Diseases, Columbia University, New York, NY, 10032, USA.
- Departments of Neurology and Neuroscience, Columbia University, New York, NY, 10032, USA.
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Peters van Ton AM, Verbeek MM, Alkema W, Pickkers P, Abdo WF. Downregulation of synapse-associated protein expression and loss of homeostatic microglial control in cerebrospinal fluid of infectious patients with delirium and patients with Alzheimer's disease. Brain Behav Immun 2020; 89:656-667. [PMID: 32592865 DOI: 10.1016/j.bbi.2020.06.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 06/18/2020] [Accepted: 06/18/2020] [Indexed: 12/16/2022] Open
Abstract
Delirium is a complex and multifactorial condition associated with long-term cognitive decline. Due to the strong links between systemic inflammation, delirium and dementia we hypothesized that responses within the brain in patients who develop delirium could show biochemical overlap with patients with Alzheimer's disease (AD). In this observational study we analyzed protein expression signatures in cerebrospinal fluid (CSF) from 15 patients with infectious delirium and compared these to 29 patients with AD, 30 infectious patients without delirium and 15 non-infectious controls free of neurological disease. A proximity extension assay was performed measuring a total of 184 inflammatory and neurology-related proteins. Eight inflammatory proteins (4%), including the key neuron-microglia communication marker CX3CL1 (fractalkine), were significantly upregulated in both delirium and AD, compared to infectious patients without delirium. Likewise, 23 proteins (13%) showed downregulation in both delirium and AD, relative to infectious patients without delirium, which interestingly included CD200R1, another neuron-microglia communication marker, as well as a cluster of proteins related to synapse formation and function. Synaptopathy is an early event in AD and correlates strongly with cognitive dysfunction. These results were partially mediated by aging, which is an important predisposing risk factor among many others for both conditions. Within this study we report the first in vivo human evidence suggesting that synapse pathology and loss of homeostatic microglial control is involved in the pathophysiology of both infectious delirium and AD and thus may provide a link for the association between infections, delirium and long-term cognitive decline.
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Affiliation(s)
- A M Peters van Ton
- Radboudumc, Radboud Institute for Molecular Life Sciences, Department of Intensive Care Medicine, Nijmegen, The Netherlands; Radboudumc, Radboud Center for Infectious Diseases, Nijmegen, The Netherlands
| | - M M Verbeek
- Radboudumc, Donders Center of Medical Neurosciences, Department of Neurology, Nijmegen, The Netherlands; Radboudumc, Department of Laboratory Medicine, Nijmegen, The Netherlands
| | - W Alkema
- Radboudumc, Radboud Institute for Molecular Life Sciences, Center for Molecular and Biomolecular Informatics, Nijmegen, The Netherlands
| | - P Pickkers
- Radboudumc, Radboud Institute for Molecular Life Sciences, Department of Intensive Care Medicine, Nijmegen, The Netherlands; Radboudumc, Radboud Center for Infectious Diseases, Nijmegen, The Netherlands
| | - W F Abdo
- Radboudumc, Radboud Institute for Molecular Life Sciences, Department of Intensive Care Medicine, Nijmegen, The Netherlands; Radboudumc, Radboud Center for Infectious Diseases, Nijmegen, The Netherlands.
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Yong Y, Gamage K, Cheng I, Barford K, Spano A, Winckler B, Deppmann C. p75NTR and DR6 Regulate Distinct Phases of Axon Degeneration Demarcated by Spheroid Rupture. J Neurosci 2019; 39:9503-9520. [PMID: 31628183 PMCID: PMC6880466 DOI: 10.1523/jneurosci.1867-19.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/11/2019] [Accepted: 10/13/2019] [Indexed: 12/19/2022] Open
Abstract
The regressive events associated with trophic deprivation are critical for sculpting a functional nervous system. After nerve growth factor withdrawal, sympathetic axons derived from male and female neonatal mice maintain their structural integrity for ∼18 h (latent phase) followed by a rapid and near unison disassembly of axons over the next 3 h (catastrophic phase). Here we examine the molecular basis by which axons transition from latent to catastrophic phases of degeneration following trophic withdrawal. Before catastrophic degeneration, we observed an increase in intra-axonal calcium. This calcium flux is accompanied by p75 neurotrophic factor receptor-Rho-actin-dependent expansion of calcium-rich axonal spheroids that eventually rupture, releasing their contents to the extracellular space. Conditioned media derived from degenerating axons are capable of hastening transition into the catastrophic phase of degeneration. We also found that death receptor 6, but not p75 neurotrophic factor receptor, is required for transition into the catastrophic phase in response to conditioned media but not for the intra-axonal calcium flux, spheroid formation, or rupture that occur toward the end of latency. Our results support the existence of an interaxonal degenerative signal that promotes catastrophic degeneration among trophically deprived axons.SIGNIFICANCE STATEMENT Developmental pruning shares several morphological similarities to both disease- and injury-induced degeneration, including spheroid formation. The function and underlying mechanisms governing axonal spheroid formation, however, remain unclear. In this study, we report that axons coordinate each other's degeneration during development via axonal spheroid rupture. Before irreversible breakdown of the axon in response to trophic withdrawal, p75 neurotrophic factor receptor-RhoA signaling governs the formation and growth of spheroids. These spheroids then rupture, allowing exchange of contents ≤10 kDa between the intracellular and extracellular space to drive death receptor 6 and calpain-dependent catastrophic degeneration. This finding informs not only our understanding of regressive events during development but may also provide a rationale for designing new treatments toward myriad neurodegenerative disorders.
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Affiliation(s)
| | - Kanchana Gamage
- Department of Cell Biology
- Amgen, Massachusetts & Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Irene Cheng
- Department of Biology
- Neuroscience Graduate Program
| | | | | | | | - Christopher Deppmann
- Department of Biology,
- Neuroscience Graduate Program
- Department of Cell Biology
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22903, and
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García-González L, Pilat D, Baranger K, Rivera S. Emerging Alternative Proteinases in APP Metabolism and Alzheimer's Disease Pathogenesis: A Focus on MT1-MMP and MT5-MMP. Front Aging Neurosci 2019; 11:244. [PMID: 31607898 PMCID: PMC6769103 DOI: 10.3389/fnagi.2019.00244] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 08/20/2019] [Indexed: 12/12/2022] Open
Abstract
Processing of amyloid beta precursor protein (APP) into amyloid-beta peptide (Aβ) by β-secretase and γ-secretase complex is at the heart of the pathogenesis of Alzheimer’s disease (AD). Targeting this proteolytic pathway effectively reduces/prevents pathology and cognitive decline in preclinical experimental models of the disease, but therapeutic strategies based on secretase activity modifying drugs have so far failed in clinical trials. Although this may raise some doubts on the relevance of β- and γ-secretases as targets, new APP-cleaving enzymes, including meprin-β, legumain (δ-secretase), rhomboid-like protein-4 (RHBDL4), caspases and membrane-type matrix metalloproteinases (MT-MMPs/η-secretases) have confirmed that APP processing remains a solid mechanism in AD pathophysiology. This review will discuss recent findings on the roles of all these proteinases in the nervous system, and in particular on the roles of MT-MMPs, which are at the crossroads of pathological events involving not only amyloidogenesis, but also inflammation and synaptic dysfunctions. Assessing the potential of these emerging proteinases in the Alzheimer’s field opens up new research prospects to improve our knowledge of fundamental mechanisms of the disease and help us establish new therapeutic strategies.
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Affiliation(s)
| | - Dominika Pilat
- Aix-Marseille Univ, CNRS, INP, Inst Neurophysiopathol, Marseille, France
| | - Kévin Baranger
- Aix-Marseille Univ, CNRS, INP, Inst Neurophysiopathol, Marseille, France
| | - Santiago Rivera
- Aix-Marseille Univ, CNRS, INP, Inst Neurophysiopathol, Marseille, France
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10
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Scharfenberg F, Armbrust F, Marengo L, Pietrzik C, Becker-Pauly C. Regulation of the alternative β-secretase meprin β by ADAM-mediated shedding. Cell Mol Life Sci 2019; 76:3193-3206. [PMID: 31201463 PMCID: PMC11105663 DOI: 10.1007/s00018-019-03179-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 05/23/2019] [Accepted: 05/29/2019] [Indexed: 12/12/2022]
Abstract
Alzheimer's Disease (AD) is the sixth-leading cause of death in industrialized countries. Neurotoxic amyloid-β (Aβ) plaques are one of the pathological hallmarks in AD patient brains. Aβ accumulates in the brain upon sequential, proteolytic processing of the amyloid precursor protein (APP) by β- and γ-secretases. However, so far disease-modifying drugs targeting β- and γ-secretase pathways seeking a decrease in the production of toxic Aβ peptides have failed in clinics. It has been demonstrated that the metalloproteinase meprin β acts as an alternative β-secretase, capable of generating truncated Aβ2-x peptides that have been described to be increased in AD patients. This indicates an important β-site cleaving enzyme 1 (BACE-1)-independent contribution of the metalloprotease meprin β within the amyloidogenic pathway and may lead to novel drug targeting avenues. However, meprin β itself is embedded in a complex regulatory network. Remarkably, the anti-amyloidogenic α-secretase a disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) is a direct competitor for APP at the cell surface, but also a sheddase of inactive pro-meprin β. Overall, we highlight the current cellular, molecular and structural understanding of meprin β as alternative β-secretase within the complex protease web, regulating APP processing in health and disease.
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Affiliation(s)
- Franka Scharfenberg
- Unit for Degradomics of the Protease Web, Biochemical Institute, University of Kiel, Kiel, Germany
| | - Fred Armbrust
- Unit for Degradomics of the Protease Web, Biochemical Institute, University of Kiel, Kiel, Germany
| | - Liana Marengo
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Claus Pietrzik
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Christoph Becker-Pauly
- Unit for Degradomics of the Protease Web, Biochemical Institute, University of Kiel, Kiel, Germany.
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Penserga T, Kudumala SR, Poulos R, Godenschwege TA. A Role for Drosophila Amyloid Precursor Protein in Retrograde Trafficking of L1-Type Cell Adhesion Molecule Neuroglian. Front Cell Neurosci 2019; 13:322. [PMID: 31354437 PMCID: PMC6640005 DOI: 10.3389/fncel.2019.00322] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/01/2019] [Indexed: 11/21/2022] Open
Abstract
The role of the Amyloid Precursor Protein (APP) in the pathology of Alzheimer’s disease (AD) has been well studied. However, the normal function of APP in the nervous system is poorly understood. Here, we characterized the role of the Drosophila homolog (APPL) in the adult giant fiber (GF) neurons. We find that endogenous APPL is transported from the synapse to the soma in the adult. Live-imaging revealed that retrograde moving APPL vesicles co-traffic with L1-type cell adhesion molecule Neuroglian (Nrg). In APPL null mutants, stationary Nrg vesicles were increased along the axon, and the number of Nrg vesicles moving in retrograde but not anterograde direction was reduced. In contrast, trafficking of endo-lysosomal vesicles, which did not co-localize with APPL in GF axons, was not affected. This suggests that APPL loss of function does not generally disrupt axonal transport but that APPL has a selective role in the effectiveness of retrograde transport of proteins it co-traffics with. While the GF terminals of APPL loss of function animals exhibited pruning defects, APPL gain of function had no disruptive effect on GF morphology and function, or on retrograde axonal transport of Nrg. However, cell-autonomous developmental expression of a secretion-deficient form of APPL (APPL-SD), lacking the α-, β-, and, γ-secretase cleavage sites, resulted in progressive retraction of the GF terminals. Conditional expression of APPL-SD in mature GFs caused accumulation of Nrg in normal sized synaptic terminals, which was associated with severely reduced retrograde flux of Nrg labeled vesicles in the axons. Albeit β-secretase null mutants developed GF terminals they also exhibited Nrg accumulations. This suggests that cleavage defective APPL has a toxic effect on retrograde trafficking and that β-secretase cleavage has a function in Nrg sorting in endosomal compartments at the synapse. In summary, our results suggest a role for APPL and its proteolytic cleavage sites in retrograde trafficking, thus our findings are of relevance to the understanding of the endogenous role of APP as well as to the development of therapeutic treatments of Alzheimer’s disease.
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Affiliation(s)
- Tyrone Penserga
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States
| | - Sirisha Rani Kudumala
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States
| | - Richelle Poulos
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States
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12
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Abstract
PURPOSE OF REVIEW The current review analyzes recent findings that suggest that axon degeneration is a druggable process in the treatment of neurodegenerative disorders and a subset of traumas. RECENT FINDINGS Emerging evidence reveals that axon degeneration is an active and regulated process in the early progression of some neurodegenerative diseases and acute traumas, which is orchestrated through a combination of axon-intrinsic and somatically derived signaling events. The identification of these pathways has presented appealing drug targets whose specificity for the nervous system and phenotypes in mouse models offers significant clinical opportunity. SUMMARY As the biology of axon degeneration becomes clear, so too has the realization that the pathways driving axon degeneration overlap in part with those that drive neuronal apoptosis and, importantly, axon regeneration. Axon-specific disorders like those seen in CIPN, where injury signaling to the nucleus is not a prominent feature, have been shown to benefit from disruption of Sarm1. In injury and disease contexts, where involvement of somatic events is prominent, inhibition of the MAP Kinase DLK exhibits promise for neuroprotection. Here, however, interfering with somatic signaling may preclude the ability of an axon or a circuit to regenerate or functionally adapt following acute injuries.
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13
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Wallach D. The Tumor Necrosis Factor Family: Family Conventions and Private Idiosyncrasies. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a028431. [PMID: 28847899 DOI: 10.1101/cshperspect.a028431] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The tumor necrosis factor (TNF) cytokine family and the TNF/nerve growth factor (NGF) family of their cognate receptors together control numerous immune functions, as well as tissue-homeostatic and embryonic-development processes. These diverse functions are dictated by both shared and distinct features of family members, and by interactions of some members with nonfamily ligands and coreceptors. The spectra of their activities are further expanded by the occurrence of the ligands and receptors in both membrane-anchored and soluble forms, by "re-anchoring" of soluble forms to extracellular matrix components, and by signaling initiation via intracellular domains (IDs) of both receptors and ligands. Much has been learned about shared features of the receptors as well as of the ligands; however, we still have only limited knowledge of the mechanistic basis for their functional heterogeneity and for the differences between their functions and those of similarly acting cytokines of other families.
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Affiliation(s)
- David Wallach
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 76100 Rehovot, Israel
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14
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Richter MC, Ludewig S, Winschel A, Abel T, Bold C, Salzburger LR, Klein S, Han K, Weyer SW, Fritz AK, Laube B, Wolfer DP, Buchholz CJ, Korte M, Müller UC. Distinct in vivo roles of secreted APP ectodomain variants APPsα and APPsβ in regulation of spine density, synaptic plasticity, and cognition. EMBO J 2018; 37:embj.201798335. [PMID: 29661886 DOI: 10.15252/embj.201798335] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 02/23/2018] [Accepted: 03/02/2018] [Indexed: 11/09/2022] Open
Abstract
Increasing evidence suggests that synaptic functions of the amyloid precursor protein (APP), which is key to Alzheimer pathogenesis, may be carried out by its secreted ectodomain (APPs). The specific roles of APPsα and APPsβ fragments, generated by non-amyloidogenic or amyloidogenic APP processing, respectively, remain however unclear. Here, we expressed APPsα or APPsβ in the adult brain of conditional double knockout mice (cDKO) lacking APP and the related APLP2. APPsα efficiently rescued deficits in spine density, synaptic plasticity (LTP and PPF), and spatial reference memory of cDKO mice. In contrast, APPsβ failed to show any detectable effects on synaptic plasticity and spine density. The C-terminal 16 amino acids of APPsα (lacking in APPsβ) proved sufficient to facilitate LTP in a mechanism that depends on functional nicotinic α7-nAChRs. Further, APPsα showed high-affinity, allosteric potentiation of heterologously expressed α7-nAChRs in oocytes. Collectively, we identified α7-nAChRs as a crucial physiological receptor specific for APPsα and show distinct in vivo roles for APPsα versus APPsβ. This implies that reduced levels of APPsα that might occur during Alzheimer pathogenesis cannot be compensated by APPsβ.
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Affiliation(s)
- Max C Richter
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Ruprecht-Karls University Heidelberg, Heidelberg, Germany
| | - Susann Ludewig
- Zoological Institute, Division of Cellular Neurobiology, TU Braunschweig, Braunschweig, Germany
| | - Alex Winschel
- Department of Biology, Neurophysiology und Neurosensory Systems, TU Darmstadt, Darmstadt, Germany
| | - Tobias Abel
- Paul-Ehrlich-Institut (PEI), Langen, Germany
| | - Charlotte Bold
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Ruprecht-Karls University Heidelberg, Heidelberg, Germany
| | - Leonie R Salzburger
- Zoological Institute, Division of Cellular Neurobiology, TU Braunschweig, Braunschweig, Germany
| | - Susanne Klein
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Ruprecht-Karls University Heidelberg, Heidelberg, Germany
| | - Kang Han
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Ruprecht-Karls University Heidelberg, Heidelberg, Germany
| | - Sascha W Weyer
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Ruprecht-Karls University Heidelberg, Heidelberg, Germany
| | - Ann-Kristina Fritz
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Institute of Human Movements Sciences and Sport, ETH Zurich, Zurich, Switzerland
| | - Bodo Laube
- Department of Biology, Neurophysiology und Neurosensory Systems, TU Darmstadt, Darmstadt, Germany
| | - David P Wolfer
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Institute of Human Movements Sciences and Sport, ETH Zurich, Zurich, Switzerland
| | | | - Martin Korte
- Zoological Institute, Division of Cellular Neurobiology, TU Braunschweig, Braunschweig, Germany.,Helmholtz Centre for Infection Research, AG NIND, Braunschweig, Germany
| | - Ulrike C Müller
- Institute of Pharmacy and Molecular Biotechnology (IPMB), Ruprecht-Karls University Heidelberg, Heidelberg, Germany
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15
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Fricker M, Tolkovsky AM, Borutaite V, Coleman M, Brown GC. Neuronal Cell Death. Physiol Rev 2018; 98:813-880. [PMID: 29488822 PMCID: PMC5966715 DOI: 10.1152/physrev.00011.2017] [Citation(s) in RCA: 654] [Impact Index Per Article: 109.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/23/2017] [Accepted: 07/10/2017] [Indexed: 02/07/2023] Open
Abstract
Neuronal cell death occurs extensively during development and pathology, where it is especially important because of the limited capacity of adult neurons to proliferate or be replaced. The concept of cell death used to be simple as there were just two or three types, so we just had to work out which type was involved in our particular pathology and then block it. However, we now know that there are at least a dozen ways for neurons to die, that blocking a particular mechanism of cell death may not prevent the cell from dying, and that non-neuronal cells also contribute to neuronal death. We review here the mechanisms of neuronal death by intrinsic and extrinsic apoptosis, oncosis, necroptosis, parthanatos, ferroptosis, sarmoptosis, autophagic cell death, autosis, autolysis, paraptosis, pyroptosis, phagoptosis, and mitochondrial permeability transition. We next explore the mechanisms of neuronal death during development, and those induced by axotomy, aberrant cell-cycle reentry, glutamate (excitoxicity and oxytosis), loss of connected neurons, aggregated proteins and the unfolded protein response, oxidants, inflammation, and microglia. We then reassess which forms of cell death occur in stroke and Alzheimer's disease, two of the most important pathologies involving neuronal cell death. We also discuss why it has been so difficult to pinpoint the type of neuronal death involved, if and why the mechanism of neuronal death matters, the molecular overlap and interplay between death subroutines, and the therapeutic implications of these multiple overlapping forms of neuronal death.
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Affiliation(s)
- Michael Fricker
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
| | - Aviva M Tolkovsky
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
| | - Vilmante Borutaite
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
| | - Michael Coleman
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
| | - Guy C Brown
- Hunter Medical Research Institute, University of Newcastle, Callaghan, New South Wales , Australia ; Department of Clinical Neurosciences, University of Cambridge , Cambridge , United Kingdom ; Neuroscience Institute, Lithuanian University of Health Sciences , Kaunas , Lithuania ; and Department of Biochemistry, University of Cambridge , Cambridge , United Kingdom
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16
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Abstract
Optic neuropathies such as glaucoma are characterized by the degeneration of retinal ganglion cells (RGCs) and the irreversible loss of vision. In these diseases, focal axon injury triggers a propagating axon degeneration and, eventually, cell death. Previous work by us and others identified dual leucine zipper kinase (DLK) and JUN N-terminal kinase (JNK) as key mediators of somal cell death signaling in RGCs following axonal injury. Moreover, others have shown that activation of the DLK/JNK pathway contributes to distal axonal degeneration in some neuronal subtypes and that this activation is dependent on the adaptor protein, sterile alpha and TIR motif containing 1 (SARM1). Given that SARM1 acts upstream of DLK/JNK signaling in axon degeneration, we tested whether SARM1 plays a similar role in RGC somal apoptosis in response to optic nerve injury. Using the mouse optic nerve crush (ONC) model, our results show that SARM1 is critical for RGC axonal degeneration and that axons rescued by SARM1 deficiency are electrophysiologically active. Genetic deletion of SARM1 did not, however, prevent DLK/JNK pathway activation in RGC somas nor did it prevent or delay RGC cell death. These results highlight the importance of SARM1 in RGC axon degeneration and suggest that somal activation of the DLK/JNK pathway is activated by an as-yet-unidentified SARM1-independent signal.
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17
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Hollville E, Deshmukh M. Physiological functions of non-apoptotic caspase activity in the nervous system. Semin Cell Dev Biol 2017; 82:127-136. [PMID: 29199140 DOI: 10.1016/j.semcdb.2017.11.037] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 11/22/2017] [Accepted: 11/29/2017] [Indexed: 12/15/2022]
Abstract
Caspases are cysteine proteases that play important and well-defined roles in apoptosis and inflammation. Increasing evidence point to alternative functions of caspases where restricted and localized caspase activation within neurons allows for a variety of non-apoptotic and non-inflammatory processes required for brain development and function. In this review, we highlight sublethal caspase functions in axon and dendrite pruning, neurite outgrowth and dendrite branches formation, as well as in long-term depression and synaptic plasticity. Importantly, as non-apoptotic activity of caspases is often confined in space and time in neurons, we also discuss the mechanisms that restrict caspase activity in order to maintain the neuronal networks in a healthy and functional state.
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Affiliation(s)
| | - Mohanish Deshmukh
- Neuroscience Center, UNC Chapel Hill, Chapel Hill, NC, USA; Department of Cell Biology and Physiology, UNC Chapel Hill, Chapel Hill, NC, USA.
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18
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HIV-1 counteracts an innate restriction by amyloid precursor protein resulting in neurodegeneration. Nat Commun 2017; 8:1522. [PMID: 29142315 PMCID: PMC5688069 DOI: 10.1038/s41467-017-01795-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 10/16/2017] [Indexed: 12/19/2022] Open
Abstract
While beta-amyloid (Aβ), a classic hallmark of Alzheimer's disease (AD) and dementia, has long been known to be elevated in the human immunodeficiency virus type 1 (HIV-1)-infected brain, why and how Aβ is produced, along with its contribution to HIV-associated neurocognitive disorder (HAND) remains ill-defined. Here, we reveal that the membrane-associated amyloid precursor protein (APP) is highly expressed in macrophages and microglia, and acts as an innate restriction against HIV-1. APP binds the HIV-1 Gag polyprotein, retains it in lipid rafts and blocks HIV-1 virion production and spread. To escape this restriction, Gag promotes secretase-dependent cleavage of APP, resulting in the overproduction of toxic Aβ isoforms. This Gag-mediated Aβ production results in increased degeneration of primary cortical neurons, and can be prevented by γ-secretase inhibitor treatment. Interfering with HIV-1's evasion of APP-mediated restriction also suppresses HIV-1 spread, offering a potential strategy to both treat infection and prevent HAND.
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19
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Liu A, Zhang Y, Han L, He G, Xie W, Zhou Z, Jia Z. Regulation of Neurotransmitter Release by Amyloid Precursor Protein Through Synapsin Phosphorylation. Neurochem Res 2017; 44:683-691. [PMID: 29052089 DOI: 10.1007/s11064-017-2418-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 10/01/2017] [Accepted: 10/09/2017] [Indexed: 12/19/2022]
Abstract
Abnormal processing of amyloid precursor protein (APP) and aggregation of the Aβ peptide are known to play a key role in the pathogenesis of Alzheimer disease, but the function of endogenous APP under normal physiological conditions remains poorly understood. In this study, we investigated presynaptic changes in APP knockout (KO) mice. We demonstrate that both sucrose-induced neurotransmission and synaptic depletion in response to high frequency stimulation are significantly enhanced in APP KO compared to wild type littermates. In addition, the level of phosphorylated forms of synapsins, but not total synapsins, is elevated in the KO mice. Furthermore, we show that the inhibition of L-type calcium channels normalizes phosphorylated synapsins and slows down the high frequency induced synaptic depletion in APP KO mice. These results suggest a new mechanism by which APP regulates synaptic vesicle dynamics through synapsin-dependent phosphorylation.
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Affiliation(s)
- An Liu
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing, 210096, China
| | - Ying Zhang
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing, 210096, China
| | - Lifang Han
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing, 210096, China
| | - Guiqin He
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing, 210096, China
| | - Wei Xie
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing, 210096, China
| | - Zikai Zhou
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, Nanjing, 210096, China
| | - Zhengping Jia
- Neurosciences & Mental Health, the Hospital for Sick Children, 555 University Ave., Toronto, ON, M5G 1X8, Canada. .,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
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20
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Sosa LJ, Cáceres A, Dupraz S, Oksdath M, Quiroga S, Lorenzo A. The physiological role of the amyloid precursor protein as an adhesion molecule in the developing nervous system. J Neurochem 2017; 143:11-29. [PMID: 28677143 DOI: 10.1111/jnc.14122] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 06/28/2017] [Accepted: 06/29/2017] [Indexed: 12/12/2022]
Abstract
The amyloid precursor protein (APP) is a type I transmembrane glycoprotein better known for its participation in the physiopathology of Alzheimer disease as the source of the beta amyloid fragment. However, the physiological functions of the full length protein and its proteolytic fragments have remained elusive. APP was first described as a cell-surface receptor; nevertheless, increasing evidence highlighted APP as a cell adhesion molecule. In this review, we will focus on the current knowledge of the physiological role of APP as a cell adhesion molecule and its involvement in key events of neuronal development, such as migration, neurite outgrowth, growth cone pathfinding, and synaptogenesis. Finally, since APP is over-expressed in Down syndrome individuals because of the extra copy of chromosome 21, in the last section of the review, we discuss the potential contribution of APP to the neuronal and synaptic defects described in this genetic condition. Read the Editorial Highlight for this article on page 9. Cover Image for this issue: doi. 10.1111/jnc.13817.
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Affiliation(s)
- Lucas J Sosa
- Departamento de Química Biológica Ranwell Caputto, Facultad de Ciencias Químicas, CIQUIBIC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Alfredo Cáceres
- Laboratorio Neurobiología, Instituto Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina.,Instituto Universitario Ciencias Biomédicas Córdoba, Córdoba, Argentina
| | - Sebastián Dupraz
- Axonal Growth and Regeneration, German Center for Neurodegenarative Diseases, Bonn, Germany
| | - Mariana Oksdath
- Departamento de Química Biológica Ranwell Caputto, Facultad de Ciencias Químicas, CIQUIBIC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Santiago Quiroga
- Departamento de Química Biológica Ranwell Caputto, Facultad de Ciencias Químicas, CIQUIBIC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Alfredo Lorenzo
- Laboratorio de Neuropatología Experimental, Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
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21
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Sato Y, Uchida Y, Hu J, Young-Pearse TL, Niikura T, Mukouyama YS. Soluble APP functions as a vascular niche signal that controls adult neural stem cell number. Development 2017; 144:2730-2736. [PMID: 28694255 DOI: 10.1242/dev.143370] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 06/29/2017] [Indexed: 12/18/2022]
Abstract
The molecular mechanism by which NSC number is controlled in the neurogenic regions of the adult brain is not fully understood but it has been shown that vascular niche signals regulate neural stem cell (NSC) quiescence and growth. Here, we have uncovered a role for soluble amyloid precursor protein (sAPP) as a vascular niche signal in the subventricular zone (SVZ) of the lateral ventricle of the adult mouse brain. sAPP suppresses NSC growth in culture. Further in vivo studies on the role of APP in regulating NSC number in the SVZ clearly demonstrate that endothelial deletion of App causes a significant increase in the number of BrdU label-retaining NSCs in the SVZ, whereas NSC/astrocyte deletion of App has no detectable effect on the NSC number. Taken together, these results suggest that endothelial APP functions as a vascular niche signal that negatively regulates NSC growth to control the NSC number in the SVZ.
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Affiliation(s)
- Yuya Sato
- Laboratory of Stem Cell and Neuro-Vascular Biology, Genetics and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/6C103, 10 Center Drive, Bethesda, MD 20892, USA
| | - Yutaka Uchida
- Laboratory of Stem Cell and Neuro-Vascular Biology, Genetics and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/6C103, 10 Center Drive, Bethesda, MD 20892, USA
| | - Jingqiong Hu
- Laboratory of Stem Cell and Neuro-Vascular Biology, Genetics and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/6C103, 10 Center Drive, Bethesda, MD 20892, USA.,Stem Cell Center, Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China
| | - Tracy L Young-Pearse
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Takako Niikura
- Department of Information and Communication Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554, Japan
| | - Yoh-Suke Mukouyama
- Laboratory of Stem Cell and Neuro-Vascular Biology, Genetics and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/6C103, 10 Center Drive, Bethesda, MD 20892, USA
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22
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Not just amyloid: physiological functions of the amyloid precursor protein family. Nat Rev Neurosci 2017; 18:281-298. [PMID: 28360418 DOI: 10.1038/nrn.2017.29] [Citation(s) in RCA: 381] [Impact Index Per Article: 54.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyloid precursor protein (APP) gives rise to the amyloid-β peptide and thus has a key role in the pathogenesis of Alzheimer disease. By contrast, the physiological functions of APP and the closely related APP-like proteins (APLPs) remain less well understood. Studying these physiological functions has been challenging and has required a careful long-term strategy, including the analysis of different App-knockout and Aplp-knockout mice. In this Review, we summarize these findings, focusing on the in vivo roles of APP family members and their processing products for CNS development, synapse formation and function, brain injury and neuroprotection, as well as ageing. In addition, we discuss the implications of APP physiology for therapeutic approaches.
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23
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Gamage KK, Cheng I, Park RE, Karim MS, Edamura K, Hughes C, Spano AJ, Erisir A, Deppmann CD. Death Receptor 6 Promotes Wallerian Degeneration in Peripheral Axons. Curr Biol 2017; 27:890-896. [PMID: 28285993 DOI: 10.1016/j.cub.2017.01.062] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/19/2016] [Accepted: 01/30/2017] [Indexed: 11/17/2022]
Abstract
Axon degeneration during development is required to sculpt a functional nervous system and is also a hallmark of pathological insult, such as injury [1, 2]. Despite similar morphological characteristics, very little overlap in molecular mechanisms has been reported between pathological and developmental degeneration [3-5]. In the peripheral nervous system (PNS), developmental axon pruning relies on receptor-mediated extrinsic degeneration mechanisms to determine which axons are maintained or degenerated [5-7]. Receptors have not been implicated in Wallerian axon degeneration; instead, axon autonomous, intrinsic mechanisms are thought to be the primary driver for this type of axon disintegration [8-10]. Here we survey the role of neuronally expressed, paralogous tumor necrosis factor receptor super family (TNFRSF) members in Wallerian degeneration. We find that an orphan receptor, death receptor 6 (DR6), is required to drive axon degeneration after axotomy in sympathetic and sensory neurons cultured in microfluidic devices. We sought to validate these in vitro findings in vivo using a transected sciatic nerve model. Consistent with the in vitro findings, DR6-/- animals displayed preserved axons up to 4 weeks after injury. In contrast to phenotypes observed in Wlds and Sarm1-/- mice, preserved axons in DR6-/- animals display profound myelin remodeling. This indicates that deterioration of axons and myelin after axotomy are mechanistically distinct processes. Finally, we find that JNK signaling after injury requires DR6, suggesting a link between this novel extrinsic pathway and the axon autonomous, intrinsic pathways that have become established for Wallerian degeneration.
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Affiliation(s)
- Kanchana K Gamage
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Irene Cheng
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22903, USA
| | - Rachel E Park
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Mardeen S Karim
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Kazusa Edamura
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Christopher Hughes
- Department of Physics and Astronomy, James Madison University, Harrisonburg, VA 22807, USA
| | - Anthony J Spano
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Alev Erisir
- Department of Psychology, University of Virginia, Charlottesville, VA 22903, USA
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24
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Ramaker JM, Copenhaver PF. Amyloid Precursor Protein family as unconventional Go-coupled receptors and the control of neuronal motility. NEUROGENESIS 2017; 4:e1288510. [PMID: 28321435 PMCID: PMC5345750 DOI: 10.1080/23262133.2017.1288510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/21/2017] [Accepted: 01/25/2017] [Indexed: 01/06/2023]
Abstract
Cleavage of the Amyloid Precursor Protein (APP) generates amyloid peptides that accumulate in Alzheimer Disease (AD), but APP is also upregulated by developing and injured neurons, suggesting that it regulates neuronal motility. APP can also function as a G protein-coupled receptor that signals via the heterotrimeric G protein Gαo, but evidence for APP-Gαo signaling in vivo has been lacking. Using Manduca as a model system, we showed that insect APP (APPL) regulates neuronal migration in a Gαo-dependent manner. Recently, we also demonstrated that Manduca Contactin (expressed by glial cells) induces APPL-Gαo retraction responses in migratory neurons, consistent with evidence that mammalian Contactins also interact with APP family members. Preliminary studies using cultured hippocampal neurons suggest that APP-Gαo signaling can similarly regulate growth cone motility. Whether Contactins (or other APP ligands) induce this response within the developing nervous system, and how this pathway is disrupted in AD, remains to be explored.
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Affiliation(s)
- Jenna M Ramaker
- Department of Cell, Developmental and Cancer Biology L-215, Oregon Health & Sciences University , Portland, OR, USA
| | - Philip F Copenhaver
- Department of Cell, Developmental and Cancer Biology L-215, Oregon Health & Sciences University , Portland, OR, USA
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Nesse RM, Finch CE, Nunn CL. Does selection for short sleep duration explain human vulnerability to Alzheimer's disease? Evol Med Public Health 2017; 2017:39-46. [PMID: 28096295 PMCID: PMC5381352 DOI: 10.1093/emph/eow035] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/15/2016] [Accepted: 12/29/2016] [Indexed: 01/17/2023] Open
Abstract
Compared with other primates, humans sleep less and have a much higher prevalence of Alzheimer 's disease (AD) pathology. This article reviews evidence relevant to the hypothesis that natural selection for shorter sleep time in humans has compromised the efficacy of physiological mechanisms that protect against AD during sleep. In particular, the glymphatic system drains interstitial fluid from the brain, removing extra-cellular amyloid beta (eAβ) twice as fast during sleep. In addition, melatonin - a peptide hormone that increases markedly during sleep - is an effective antioxidant that inhibits the polymerization of soluble eAβ into insoluble amyloid fibrils that are associated with AD. Sleep deprivation increases plaque formation and AD, which itself disrupts sleep, potentially creating a positive feedback cycle. These and other physiological benefits of sleep may be compromised by short sleep durations. Our hypothesis highlights possible long-term side effects of medications that reduce sleep, and may lead to potential new strategies for preventing and treating AD.
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Affiliation(s)
| | - Caleb E Finch
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
| | - Charles L Nunn
- Department of Evolutionary Anthropology and Duke Global Health Institute, Duke University, Durham, NC 27708
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26
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Death receptor 6 is a novel plasmacytoid dendritic cell-specific receptor and modulates type I interferon production. Protein Cell 2016; 7:291-294. [PMID: 26906057 PMCID: PMC4818848 DOI: 10.1007/s13238-015-0239-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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27
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Copenhaver PF, Ramaker JM. Neuronal migration during development and the amyloid precursor protein. CURRENT OPINION IN INSECT SCIENCE 2016; 18:1-10. [PMID: 27939704 PMCID: PMC5157842 DOI: 10.1016/j.cois.2016.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 08/06/2016] [Indexed: 06/06/2023]
Abstract
The Amyloid Precursor Protein (APP) is the source of amyloid peptides that accumulate in Alzheimer's disease. However, members of the APP family are strongly expressed in the developing nervous systems of invertebrates and vertebrates, where they regulate neuronal guidance, synaptic remodeling, and injury responses. In contrast to mammals, insects express only one APP ortholog (APPL), simplifying investigations into its normal functions. Recent studies have shown that APPL regulates neuronal migration in the developing insect nervous system, analogous to the roles ascribed to APP family proteins in the mammalian cortex. The comparative simplicity of insect systems offers new opportunities for deciphering the signaling mechanisms by which this enigmatic class of proteins contributes to the formation and function of the nervous system.
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Affiliation(s)
- Philip F Copenhaver
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, OR 97239, USA.
| | - Jenna M Ramaker
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, OR 97239, USA; Department of Pathology, Oregon Health & Science University, Portland, OR 97239, USA
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28
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Ramaker JM, Cargill RS, Swanson TL, Quirindongo H, Cassar M, Kretzschmar D, Copenhaver PF. Amyloid Precursor Proteins Are Dynamically Trafficked and Processed during Neuronal Development. Front Mol Neurosci 2016; 9:130. [PMID: 27932950 PMCID: PMC5122739 DOI: 10.3389/fnmol.2016.00130] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/10/2016] [Indexed: 01/10/2023] Open
Abstract
Proteolytic processing of the Amyloid Precursor Protein (APP) produces beta-amyloid (Aβ) peptide fragments that accumulate in Alzheimer's Disease (AD), but APP may also regulate multiple aspects of neuronal development, albeit via mechanisms that are not well understood. APP is a member of a family of transmembrane glycoproteins expressed by all higher organisms, including two mammalian orthologs (APLP1 and APLP2) that have complicated investigations into the specific activities of APP. By comparison, insects express only a single APP-related protein (APP-Like, or APPL) that contains the same protein interaction domains identified in APP. However, unlike its mammalian orthologs, APPL is only expressed by neurons, greatly simplifying an analysis of its functions in vivo. Like APP, APPL is processed by secretases to generate a similar array of extracellular and intracellular cleavage fragments, as well as an Aβ-like fragment that can induce neurotoxic responses in the brain. Exploiting the complementary advantages of two insect models (Drosophila melanogaster and Manduca sexta), we have investigated the regulation of APPL trafficking and processing with respect to different aspects of neuronal development. By comparing the behavior of endogenously expressed APPL with fluorescently tagged versions of APPL and APP, we have shown that some full-length protein is consistently trafficked into the most motile regions of developing neurons both in vitro and in vivo. Concurrently, much of the holoprotein is rapidly processed into N- and C-terminal fragments that undergo bi-directional transport within distinct vesicle populations. Unexpectedly, we also discovered that APPL can be transiently sequestered into an amphisome-like compartment in developing neurons, while manipulations targeting APPL cleavage altered their motile behavior in cultured embryos. These data suggest that multiple mechanisms restrict the bioavailability of the holoprotein to regulate APPL-dependent responses within the nervous system. Lastly, targeted expression of our double-tagged constructs (combined with time-lapse imaging) revealed that APP family proteins are subject to complex patterns of trafficking and processing that vary dramatically between different neuronal subtypes. In combination, our results provide a new perspective on how the regulation of APP family proteins can be modulated to accommodate a variety of cell type-specific responses within the embryonic and adult nervous system.
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Affiliation(s)
- Jenna M Ramaker
- Department of Cell, Developmental and Cancer Biology, Oregon Health and Science UniversityPortland, OR, USA; Neuroscience Graduate Program, Oregon Health and Science UniversityPortland, OR, USA
| | - Robert S Cargill
- Oregon Institute of Occupational Health Sciences, Oregon Health and Science University Portland, OR, USA
| | - Tracy L Swanson
- Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University Portland, OR, USA
| | - Hanil Quirindongo
- Oregon Institute of Occupational Health Sciences, Oregon Health and Science University Portland, OR, USA
| | - Marlène Cassar
- Oregon Institute of Occupational Health Sciences, Oregon Health and Science University Portland, OR, USA
| | - Doris Kretzschmar
- Oregon Institute of Occupational Health Sciences, Oregon Health and Science University Portland, OR, USA
| | - Philip F Copenhaver
- Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University Portland, OR, USA
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29
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Andrew RJ, Kellett KAB, Thinakaran G, Hooper NM. A Greek Tragedy: The Growing Complexity of Alzheimer Amyloid Precursor Protein Proteolysis. J Biol Chem 2016; 291:19235-44. [PMID: 27474742 DOI: 10.1074/jbc.r116.746032] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Proteolysis of the amyloid precursor protein (APP) liberates various fragments including the proposed initiator of Alzheimer disease-associated dysfunctions, amyloid-β. However, recent evidence suggests that the accepted view of APP proteolysis by the canonical α-, β-, and γ-secretases is simplistic, with the discovery of a number of novel APP secretases (including δ- and η-secretases, alternative β-secretases) and additional metabolites, some of which may also cause synaptic dysfunction. Furthermore, various proteins have been identified that interact with APP and modulate its cleavage by the secretases. Here, we give an overview of the increasingly complex picture of APP proteolysis.
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Affiliation(s)
- Robert J Andrew
- From the Departments of Neurobiology, Neurology, and Pathology, The University of Chicago, Chicago, Illinois 60637 and
| | - Katherine A B Kellett
- the Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Gopal Thinakaran
- From the Departments of Neurobiology, Neurology, and Pathology, The University of Chicago, Chicago, Illinois 60637 and
| | - Nigel M Hooper
- the Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom
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30
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Physiological role for amyloid precursor protein in adult experience-dependent plasticity. Proc Natl Acad Sci U S A 2016; 113:7912-7. [PMID: 27354516 DOI: 10.1073/pnas.1604299113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Changes in neural circuits after experience-dependent plasticity are brought about by the formation of new circuits via axonal growth and pruning. Here, using a combination of electrophysiology, adeno-associated virus-delivered fluorescent proteins, analysis of mutant mice, and two-photon microscopy, we follow long-range horizontally projecting axons in primary somatosensory cortex before and after selective whisker plucking. Whisker plucking induces axonal growth and pruning of horizontal projecting axons from neurons located in the surrounding intact whisker representations. We report that amyloid precursor protein is crucial for axonal pruning and contributes in a cell autonomous way.
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31
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Axon degeneration: context defines distinct pathways. Curr Opin Neurobiol 2016; 39:108-15. [PMID: 27197022 DOI: 10.1016/j.conb.2016.05.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/02/2016] [Accepted: 05/03/2016] [Indexed: 12/29/2022]
Abstract
Axon degeneration is an essential part of development, plasticity, and injury response and has been primarily studied in mammalian models in three contexts: 1) Axotomy-induced Wallerian degeneration, 2) Apoptosis-induced axon degeneration (axon apoptosis), and 3) Axon pruning. These three contexts dictate engagement of distinct pathways for axon degeneration. Recent advances have identified the importance of SARM1, NMNATs, NAD+ depletion, and MAPK signaling in axotomy-induced Wallerian degeneration. Interestingly, apoptosis-induced axon degeneration and axon pruning have many shared mechanisms both in signaling (e.g. DLK, JNKs, GSK3α/β) and execution (e.g. Puma, Bax, caspase-9, caspase-3). However, the specific mechanisms by which caspases are activated during apoptosis versus pruning appear distinct, with apoptosis requiring Apaf-1 but not caspase-6 while pruning requires caspase-6 but not Apaf-1.
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32
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Sundberg JP, Berndt A, Sundberg BA, Silva KA, Kennedy V, Smith RS, Cooper TK, Schofield PN. Approaches to Investigating Complex Genetic Traits in a Large-Scale Inbred Mouse Aging Study. Vet Pathol 2016; 53:456-67. [PMID: 26936752 PMCID: PMC5297262 DOI: 10.1177/0300985815612556] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Inbred mice are a unique model system for studying aging because of the genetic homogeneity within inbred strains, the short life span of mice relative to humans, and the rich array of analytic tools that are available. A large-scale aging study was conducted on 28 inbred strains representing great genetic diversity to determine, via histopathology, the type and diversity of spontaneous diseases that aging mice develop. A total of 20 885 different diagnoses were made, with an average of 12 diagnoses per mouse in the study. Eighteen inbred strains have had their genomes sequenced, and many others have been partially sequenced to provide large repositories of data on genetic variation among the strains. This vast amount of genomic information can be utilized in genome-wide association studies to find candidate genes that are involved in the pathogenesis of spontaneous diseases. As an illustration, this article presents a genome-wide association study of the genetic associations of age-related intestinal amyloidosis, which implicated 3 candidate genes: translocating chain-associated membrane protein 1 (Tram1); splicing factor 3b, subunit 5 (Sf3b5); and syntaxin 11 (Stx11). Representative photomicrographs are available on the Mouse Tumor Biology Database and Pathbase to serve as a reference when evaluating inbred mice used in other genetic or experimental studies to rule out strain background lesions. Many of the age-related mouse diseases are similar, if not identical, to human diseases; therefore, the genetic discoveries have direct translational benefit.
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Affiliation(s)
| | - A Berndt
- University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | | | - K A Silva
- The Jackson Laboratory, Bar Harbor, ME, USA
| | - V Kennedy
- The Jackson Laboratory, Bar Harbor, ME, USA
| | - R S Smith
- The Jackson Laboratory, Bar Harbor, ME, USA
| | - T K Cooper
- Department of Comparative Medicine, Department of Pathology, Penn State Milton S. Hershey Medical Center, College of Medicine, Hershey, PA, USA
| | - P N Schofield
- The Jackson Laboratory, Bar Harbor, ME, USA Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, UK
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33
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Unsain N, Barker PA. New Views on the Misconstrued: Executioner Caspases and Their Diverse Non-apoptotic Roles. Neuron 2016; 88:461-74. [PMID: 26539888 DOI: 10.1016/j.neuron.2015.08.029] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Initially characterized for their roles in apoptosis, executioner caspases have emerged as important regulators of an array of cellular activities. This is especially true in the nervous system, where sublethal caspase activity has been implicated in axonal pathfinding and branching, axonal degeneration, dendrite pruning, regeneration, long-term depression, and metaplasticity. Here we examine the roles of sublethal executioner caspase activity in nervous system development and maintenance, consider the mechanisms that locally activate and restrain these potential killers, and discuss how their activity be subverted in neurodegenerative disease.
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Affiliation(s)
- Nicolas Unsain
- Laboratorio de Neurobiología, Instituto de Investigación Médica Mercedes y Martín Ferreyra, Instituto Nacional de Investigación Médica Córdoba-Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional de Córdoba, Friuli 2434, Córdoba (5016), Argentina
| | - Philip A Barker
- Irving K. Barber School of Arts and Sciences, University of British Columbia, Kelowna, BC V1V 1V7, Canada.
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34
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APP Receptor? To Be or Not To Be. Trends Pharmacol Sci 2016; 37:390-411. [PMID: 26837733 DOI: 10.1016/j.tips.2016.01.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/07/2016] [Accepted: 01/11/2016] [Indexed: 11/22/2022]
Abstract
Amyloid precursor protein (APP) and its metabolites play a key role in Alzheimer's disease pathogenesis. The idea that APP may function as a receptor has gained momentum based on its structural similarities to type I transmembrane receptors and the identification of putative APP ligands. We review the recent experimental evidence in support of this notion and discuss how this concept is viewed in the field. Specifically, we focus on the structural and functional characteristics of APP as a cell surface receptor, and on its interaction with adaptors and signaling proteins. We also address the importance of APP function as a receptor in Alzheimer's disease etiology and discuss how this function might be potentially important for the development of novel therapeutic approaches.
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35
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Abstract
The assembly of functional neural circuits requires the combined action of progressive and regressive events. Regressive events encompass a variety of inhibitory developmental processes, including axon and dendrite pruning, which facilitate the removal of exuberant neuronal connections. Most axon pruning involves the removal of axons that had already made synaptic connections; thus, axon pruning is tightly associated with synapse elimination. In many instances, these developmental processes are regulated by the interplay between neurons and glial cells that act instructively during neural remodeling. Owing to the importance of axon and dendritic pruning, these remodeling events require precise spatial and temporal control, and this is achieved by a range of distinct molecular mechanisms. Disruption of these mechanisms results in abnormal pruning, which has been linked to brain dysfunction. Therefore, understanding the mechanisms of axon and dendritic pruning will be instrumental in advancing our knowledge of neural disease and mental disorders.
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Affiliation(s)
- Martin M Riccomagno
- Department of Cell Biology and Neuroscience, University of California, Riverside, California 92521;
| | - Alex L Kolodkin
- Solomon H. Snyder Department of Neuroscience, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
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36
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Pasciuto E, Ahmed T, Wahle T, Gardoni F, D’Andrea L, Pacini L, Jacquemont S, Tassone F, Balschun D, Dotti C, Callaerts-Vegh Z, D’Hooge R, Müller U, Di Luca M, De Strooper B, Bagni C. Dysregulated ADAM10-Mediated Processing of APP during a Critical Time Window Leads to Synaptic Deficits in Fragile X Syndrome. Neuron 2015; 87:382-98. [DOI: 10.1016/j.neuron.2015.06.032] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Revised: 04/23/2015] [Accepted: 06/23/2015] [Indexed: 10/23/2022]
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37
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Contactin-4 mediates axon-target specificity and functional development of the accessory optic system. Neuron 2015; 86:985-999. [PMID: 25959733 DOI: 10.1016/j.neuron.2015.04.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 02/19/2015] [Accepted: 03/31/2015] [Indexed: 12/31/2022]
Abstract
The mammalian eye-to-brain pathway includes more than 20 parallel circuits, each consisting of precise long-range connections between specific sets of retinal ganglion cells (RGCs) and target structures in the brain. The mechanisms that drive assembly of these parallel connections and the functional implications of their specificity remain unresolved. Here we show that in the absence of contactin 4 (CNTN4) or one of its binding partners, amyloid precursor protein (APP), a subset of direction-selective RGCs fail to target the nucleus of the optic tract (NOT)--the accessory optic system (AOS) target controlling horizontal image stabilization. Conversely, ectopic expression of CNTN4 biases RGCs to arborize in the NOT, and that process also requires APP. Our data reveal critical and novel roles for CNTN4/APP in promoting target-specific axon arborization, and they highlight the importance of this process for functional development of a behaviorally relevant parallel visual pathway.
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38
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van der Kant R, Goldstein LSB. Cellular functions of the amyloid precursor protein from development to dementia. Dev Cell 2015; 32:502-15. [PMID: 25710536 DOI: 10.1016/j.devcel.2015.01.022] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Amyloid precursor protein (APP) is a key player in Alzheimer's disease (AD). The Aβ fragments of APP are the major constituent of AD-associated amyloid plaques, and mutations or duplications of the gene coding for APP can cause familial AD. Here we review the roles of APP in neuronal development, signaling, intracellular transport, and other aspects of neuronal homeostasis. We suggest that APP acts as a signaling nexus that transduces information about a range of extracellular conditions, including neuronal damage, to induction of intracellular signaling events. Subtle disruptions of APP signaling functions may be major contributors to AD-causing neuronal dysfunction.
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Affiliation(s)
- Rik van der Kant
- Department of Cellular and Molecular Medicine, University of California-San Diego, La Jolla, CA 92093, USA.
| | - Lawrence S B Goldstein
- Department of Cellular and Molecular Medicine, University of California-San Diego, La Jolla, CA 92093, USA.
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39
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The crystal structure of DR6 in complex with the amyloid precursor protein provides insight into death receptor activation. Genes Dev 2015; 29:785-90. [PMID: 25838500 PMCID: PMC4403255 DOI: 10.1101/gad.257675.114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/09/2015] [Indexed: 11/25/2022]
Abstract
Death receptor 6 (DR6) was recently shown to bind amyloid precursor protein (APP) via the protein extracellular regions, stimulate axonal pruning, and inhibit synapse formation. Xu et al. report the crystal structure of the DR6 ectodomain in complex with the E2 domain of APP and show that it supports a model for APP-induced dimerization and activation of cell surface DR6. The amyloid precursor protein (APP) has garnered considerable attention due to its genetic links to Alzheimer's disease. Death receptor 6 (DR6) was recently shown to bind APP via the protein extracellular regions, stimulate axonal pruning, and inhibit synapse formation. Here, we report the crystal structure of the DR6 ectodomain in complex with the E2 domain of APP and show that it supports a model for APP-induced dimerization and activation of cell surface DR6.
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40
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The multifaceted nature of amyloid precursor protein and its proteolytic fragments: friends and foes. Acta Neuropathol 2015; 129:1-19. [PMID: 25287911 DOI: 10.1007/s00401-014-1347-2] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 09/26/2014] [Accepted: 09/26/2014] [Indexed: 12/29/2022]
Abstract
The amyloid precursor protein (APP) has occupied a central position in Alzheimer's disease (AD) pathophysiology, in large part due to the seminal role of amyloid-β peptide (Aβ), a proteolytic fragment derived from APP. Although the contribution of Aβ to AD pathogenesis is accepted by many in the research community, recent studies have unveiled a more complicated picture of APP's involvement in neurodegeneration in that other APP-derived fragments have been shown to exert pathological influences on neuronal function. However, not all APP-derived peptides are neurotoxic, and some even harbor neuroprotective effects. In this review, we will explore this complex picture by first discussing the pleiotropic effects of the major APP-derived peptides cleaved by multiple proteases, including soluble APP peptides (sAPPα, sAPPβ), various C- and N-terminal fragments, p3, and APP intracellular domain fragments. In addition, we will highlight two interesting sequences within APP that likely contribute to this duality in APP function. First, it has been found that caspase-mediated cleavage of APP in the cytosolic region may release a cytotoxic peptide, C31, which plays a role in synapse loss and neuronal death. Second, recent studies have implicated the -YENPTY- motif in the cytoplasmic region as a domain that modulates several APP activities through phosphorylation and dephosphorylation of the first tyrosine residue. Thus, this review summarizes the current understanding of various APP proteolytic products and the interplay among them to gain deeper insights into the possible mechanisms underlying neurodegeneration and AD pathophysiology.
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41
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Martin DDO, Ladha S, Ehrnhoefer DE, Hayden MR. Autophagy in Huntington disease and huntingtin in autophagy. Trends Neurosci 2014; 38:26-35. [PMID: 25282404 DOI: 10.1016/j.tins.2014.09.003] [Citation(s) in RCA: 219] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/08/2014] [Accepted: 09/09/2014] [Indexed: 01/20/2023]
Abstract
Autophagy is an important biological process that is essential for the removal of damaged organelles and toxic or aggregated proteins by delivering them to the lysosome for degradation. Consequently, autophagy has become a primary target for the treatment of neurodegenerative diseases that involve aggregating proteins. In Huntington disease (HD), an expansion of the polyglutamine (polyQ) tract in the N-terminus of the huntingtin (HTT) protein leads to protein aggregation. However, HD is unique among the neurodegenerative proteinopathies in that autophagy is not only dysfunctional but wild type (wt) HTT also appears to play several roles in regulating the dynamics of autophagy. Herein, we attempt to integrate the recently described novel roles of wtHTT and altered autophagy in HD.
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Affiliation(s)
- Dale D O Martin
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada.
| | - Safia Ladha
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Dagmar E Ehrnhoefer
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada.
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42
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Pease SE, Segal RA. Preserve and protect: maintaining axons within functional circuits. Trends Neurosci 2014; 37:572-82. [PMID: 25167775 DOI: 10.1016/j.tins.2014.07.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 07/21/2014] [Accepted: 07/27/2014] [Indexed: 12/14/2022]
Abstract
During development, neural circuits are initially generated by exuberant innervation and are rapidly refined by selective preservation and elimination of axons. The establishment and maintenance of functional circuits therefore requires coordination of axon survival and degeneration pathways. Both developing and mature circuits rely on interdependent mitochondrial and cytoskeletal components to maintain axonal health and homeostasis; injury or diseases that impinge on these components frequently cause pathologic axon loss. Here, we review recent findings that identify mechanisms of axonal preservation in the contexts of development, injury, and disease.
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Affiliation(s)
- Sarah E Pease
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Rosalind A Segal
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA.
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43
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Xu Y, Wang D, Luo Y, Li W, Shan Y, Tan X, Zhu C. Beta amyloid-induced upregulation of death receptor 6 accelerates the toxic effect of N-terminal fragment of amyloid precursor protein. Neurobiol Aging 2014; 36:157-68. [PMID: 25150572 DOI: 10.1016/j.neurobiolaging.2014.07.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 06/29/2014] [Accepted: 07/21/2014] [Indexed: 12/18/2022]
Abstract
Amyloid precursor protein (APP) plays essential roles in the development of the Alzheimer's disease. Although full-length APP has been thoroughly studied, the role of the cleavage fragments especially the N-terminal fragments (N-APPs) in Alzheimer's disease pathogenesis was still elusive. In this study, we demonstrated that application of recombinant APP₁₈₋₂₈₆ could enhance beta amyloid (Aβ)-induced neuronal injuries which were related to the activation of apoptosis proteins. Aβ treatment could induce a slight increase of N-APPs release. In addition, expression of death receptor 6 (DR6) was increased in Aβ-treated neurons and APP transgenic mice. Moreover, the effect of APP₁₈₋₂₈₆ on Aβ-induced injuries could be suppressed by the application of recombinant DR6₄₁₋₃₄₁ and DR6 antibody. Furthermore, pull-down assay revealed that APP₁₈₋₂₈₆ could bind both exogenous and endogenous DR6. Aβ promoted APP₁₈₋₂₈₆ targeting to neuron which was accompanied with the increase of DR6 expression, whereas downregulation of DR6 by interference RNA could alleviate the binding of N-APPs to neuron and also suppressed Aβ-dependent toxic effect with N-APPs. These results suggested that APP N-terminal fragments might play neurotoxic roles in Aβ-induced neuronal injuries through cell surface DR6.
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Affiliation(s)
- Yuxia Xu
- State Key Laboratory of Medical Neurobiology, Department of Neurobiology and Institutes of Brain Science, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Dandan Wang
- State Key Laboratory of Medical Neurobiology, Department of Neurobiology and Institutes of Brain Science, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Ying Luo
- Department of Chemistry and Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - Wei Li
- Department of Chemistry and Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - Ye Shan
- State Key Laboratory of Medical Neurobiology, Department of Neurobiology and Institutes of Brain Science, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Xiangshi Tan
- Department of Chemistry and Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - Cuiqing Zhu
- State Key Laboratory of Medical Neurobiology, Department of Neurobiology and Institutes of Brain Science, School of Basic Medical Science, Fudan University, Shanghai, China.
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A death receptor 6-amyloid precursor protein pathway regulates synapse density in the mature CNS but does not contribute to Alzheimer's disease-related pathophysiology in murine models. J Neurosci 2014; 34:6425-37. [PMID: 24806669 DOI: 10.1523/jneurosci.4963-13.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Recent studies implicate death receptor 6 (DR6) in an amyloid precursor protein (APP)-dependent pathway regulating developmental axon pruning, and in a pruning pathway operating during plastic rearrangements in adult brain. DR6 has also been suggested to mediate toxicity in vitro of Aβ peptides derived from APP. Given the link between APP, Aβ, and Alzheimer's disease (AD), these findings have raised the possibility that DR6 contributes to aspects of neurodegeneration in AD. To test this possibility, we have used mouse models to characterize potential function(s) of DR6 in the adult CNS and in AD-related pathophysiology. We show that DR6 is broadly expressed within the adult CNS and regulates the density of excitatory synaptic connections onto pyramidal neurons in a genetic pathway with APP. DR6 knock-out also gives rise to behavioral abnormalities, some of which are similar to those previously documented in APP knock-out animals. However, in two distinct APP transgenic models of AD, we did not observe any alteration in the formation of amyloid plaques, gliosis, synaptic loss, or cognitive behavioral deficits with genetic deletion of DR6, though we did observe a transient reduction in the degree of microglial activation in one model. Our results support the view that DR6 functions with APP to modulate synaptic density in the adult CNS, but do not provide evidence for a role of DR6 in the pathophysiology of AD.
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