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A role for APP in Wnt signalling links synapse loss with β-amyloid production. Transl Psychiatry 2018; 8:179. [PMID: 30232325 PMCID: PMC6145937 DOI: 10.1038/s41398-018-0231-6] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 07/24/2018] [Indexed: 01/18/2023] Open
Abstract
In Alzheimer's disease (AD), the canonical Wnt inhibitor Dickkopf-1 (Dkk1) is induced by β-amyloid (Aβ) and shifts the balance from canonical towards non-canonical Wnt signalling. Canonical (Wnt-β-catenin) signalling promotes synapse stability, while non-canonical (Wnt-PCP) signalling favours synapse retraction; thus Aβ-driven synapse loss is mediated by Dkk1. Here we show that the Amyloid Precursor Protein (APP) co-activates both arms of Wnt signalling through physical interactions with Wnt co-receptors LRP6 and Vangl2, to bi-directionally modulate synapse stability. Furthermore, activation of non-canonical Wnt signalling enhances Aβ production, while activation of canonical signalling suppresses Aβ production. Together, these findings identify a pathogenic-positive feedback loop in which Aβ induces Dkk1 expression, thereby activating non-canonical Wnt signalling to promote synapse loss and drive further Aβ production. The Swedish familial AD variant of APP (APPSwe) more readily co-activates non-canonical, at the expense of canonical Wnt activity, indicating that its pathogenicity likely involves direct effects on synapses, in addition to increased Aβ production. Finally, we report that pharmacological inhibition of the Aβ-Dkk1-Aβ positive feedback loop with the drug fasudil can restore the balance between Wnt pathways, prevent dendritic spine withdrawal in vitro, and reduce Aβ load in vivo in mice with advanced amyloid pathology. These results clarify a relationship between Aβ accumulation and synapse loss and provide direction for the development of potential disease-modifying treatments.
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52
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Eleutherio E, Brasil ADA, França MB, de Almeida DSG, Rona GB, Magalhães RSS. Oxidative stress and aging: Learning from yeast lessons. Fungal Biol 2018; 122:514-525. [DOI: 10.1016/j.funbio.2017.12.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 02/06/2023]
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53
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Ovchinnikov DA, Korn O, Virshup I, Wells CA, Wolvetang EJ. The Impact of APP on Alzheimer-like Pathogenesis and Gene Expression in Down Syndrome iPSC-Derived Neurons. Stem Cell Reports 2018; 11:32-42. [PMID: 29861166 PMCID: PMC6066957 DOI: 10.1016/j.stemcr.2018.05.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 05/03/2018] [Accepted: 05/04/2018] [Indexed: 12/17/2022] Open
Abstract
Early-onset Alzheimer disease (AD)-like pathology in Down syndrome is commonly attributed to an increased dosage of the amyloid precursor protein (APP) gene. To test this in an isogenic human model, we deleted the supernumerary copy of the APP gene in trisomic Down syndrome induced pluripotent stem cells or upregulated APP expression in euploid human pluripotent stem cells using CRISPRa. Cortical neuronal differentiation shows that an increased APP gene dosage is responsible for increased β-amyloid production, altered Aβ42/40 ratio, and deposition of the pyroglutamate (E3)-containing amyloid aggregates, but not for several tau-related AD phenotypes or increased apoptosis. Transcriptome comparisons demonstrate that APP has a widespread and temporally modulated impact on neuronal gene expression. Collectively, these data reveal an important role for APP in the amyloidogenic aspects of AD but challenge the idea that increased APP levels are solely responsible for increasing specific phosphorylated forms of tau or enhanced neuronal cell death in Down syndrome-associated AD pathogenesis.
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Affiliation(s)
- Dmitry A Ovchinnikov
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD 4072, Australia
| | - Othmar Korn
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD 4072, Australia
| | - Isaac Virshup
- Centre for Stem Cell Systems, MDHS, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Christine A Wells
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD 4072, Australia; Centre for Stem Cell Systems, MDHS, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Ernst J Wolvetang
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD 4072, Australia.
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54
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Functional analysis of juxta- and intra-membrane domains of murine APP by genome editing in Neuro2a cells. Biochem Biophys Res Commun 2018; 501:1023-1028. [PMID: 29777707 DOI: 10.1016/j.bbrc.2018.05.102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Accepted: 05/15/2018] [Indexed: 11/20/2022]
Abstract
Amyloid-β precursor protein (APP) correlates with the pathogenesis of certain brain diseases, such as Alzheimer disease (AD). APP is cleaved by several enzymes to produce APP metabolites, including the amyloid beta peptide (Aβ), which accumulates in the brain of AD patients. However, the exact functions of APP metabolites remain elusive. In this study, using genome editing technology, we mutated juxta- and intra-membrane domains of murine APP in the mouse neuroblastoma cell line, Neuro2a. We identified several clones that expressed characteristic patterns of APP metabolites. Mutations in juxta- (deletion 673A), and intra-membrane (deletion 705-6LM) domains of APP, decreased overall levels of APP metabolites or decreased the level of α-secretase-cleaved carboxy-terminal fragment (αCTF), respectively. APP is known to influence neuronal differentiation; therefore, we used theses clones to dissect the function of APP metabolites during neuronal differentiation. One clone (CA), which expressed reduced levels of both FL-APP and αCTF, showed increased expression of the neuronal marker, β3-tubulin, and enhanced retinoic acid (RA)-induced neurite outgrowth. In contrast, a clone that expressed FL-APP, but was devoid of αCTF (CE), showed comparable expression of β3-tubulin and neurite outgrowth compared with normal Neuro2a cells. These data indicate that FL-APP is a suppressor of neurite outgrowth. Our data suggest a novel regulatory function of juxta- and intra-membrane domains on the metabolism and function of APP.
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55
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Luu L, Ciccotosto GD, Vella LJ, Cheng L, Roisman LC, Multhaup G, Hill AF, Munter LM, Cappai R. Amyloid Precursor Protein Dimerisation Reduces Neurite Outgrowth. Mol Neurobiol 2018; 56:13-28. [PMID: 29675574 DOI: 10.1007/s12035-018-1070-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 04/09/2018] [Indexed: 02/08/2023]
Abstract
The amyloid precursor protein (APP) undergoes extensive metabolism, and its transport and proteolytic processing can be modulated by its ability to form a homodimer. We have investigated the functional consequences of stabilised APP dimer expression in cells by studying the engineered dimerisation of the APPL17C (residue 17 in Aβ sequence) construct, which is associated with a 30% increase in APP dimer expression, on APP's neurite outgrowth promoting activity. Overexpression of APPL17C in SH-SY5Y cells decreased neurite outgrowth upon retinoic acid differentiation as compared to overexpressing APPWT cells. The APPL17C phenotype was rescued by replacing the APPL17C media with conditioned media from APPWT cells, indicating that the APPL17C mutant is impairing the secretion of a neuritogenic promoting factor. APPL17C had altered transport and was localised in the endoplasmic reticulum. Defining the molecular basis of the APPL17C phenotype showed that RhoA GTPase activity, a negative regulator of neurite outgrowth, was increased in APPL17C cells. RhoA activity was decreased after APPWT conditioned media rescue. Moreover, treatment with the RhoA inhibitor, Y27632, restored a wild-type morphology to the APPL17C cells. Small RNAseq analysis of APPL17C and APPWT cells identified several differentially expressed miRNAs relating to neurite outgrowth. Of these, miR-34a showed the greatest decrease in expression. Lentiviral-mediated overexpression of miR-34a rescued neurite outgrowth in APPL17C cells to APPWT levels and changed RhoA activation. This study has identified a novel link between APP dimerisation and its neuritogenic activity which is mediated by miR-34a expression.
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Affiliation(s)
- Luan Luu
- Department of Pathology, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Giuseppe D Ciccotosto
- Department of Pathology, The University of Melbourne, Melbourne, VIC, 3010, Australia.,Department of Pharmacology & Therapeutics, The University of Melbourne, Melbourne, VIC, 3010, Australia.,Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Laura J Vella
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Lesley Cheng
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Laila C Roisman
- Department of Pathology, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Gerhard Multhaup
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Andrew F Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, 3086, Australia
| | - Lisa-Marie Munter
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Roberto Cappai
- Department of Pathology, The University of Melbourne, Melbourne, VIC, 3010, Australia. .,Department of Pharmacology & Therapeutics, The University of Melbourne, Melbourne, VIC, 3010, Australia.
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56
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Chang JL, Hinrich AJ, Roman B, Norrbom M, Rigo F, Marr RA, Norstrom EM, Hastings ML. Targeting Amyloid-β Precursor Protein, APP, Splicing with Antisense Oligonucleotides Reduces Toxic Amyloid-β Production. Mol Ther 2018; 26:1539-1551. [PMID: 29628304 DOI: 10.1016/j.ymthe.2018.02.029] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 02/21/2018] [Accepted: 02/27/2018] [Indexed: 12/22/2022] Open
Abstract
Alterations in amyloid beta precursor protein (APP) have been implicated in cognitive decline in Alzheimer's disease (AD), which is accelerated in Down syndrome/Trisomy 21 (DS/TS21), likely due to the extra copy of the APP gene, located on chromosome 21. Proteolytic cleavage of APP generates amyloid-β (Aβ) peptide, the primary component of senile plaques associated with AD. Reducing Aβ production is predicted to lower plaque burden and mitigate AD symptoms. Here, we designed a splice-switching antisense oligonucleotide (SSO) that causes skipping of the APP exon that encodes proteolytic cleavage sites required for Aβ peptide production. The SSO induced exon skipping in Down syndrome cell lines, resulting in a reduction of Aβ. Treatment of mice with the SSO resulted in widespread distribution in the brain accompanied by APP exon skipping and a reduction of Aβ. Overall, we show that an alternatively spliced isoform of APP encodes a cleavage-incompetent protein that does not produce Aβ peptide and that promoting the production of this isoform with an SSO can reduce Aβ in vivo. These findings demonstrate the utility of using SSOs to induce a spliced isoform of APP to reduce Aβ as a potential approach for treating AD.
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Affiliation(s)
- Jennifer L Chang
- Department of Cell Biology and Anatomy, Center for Genetic Diseases, Chicago Medical School and School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Anthony J Hinrich
- Department of Cell Biology and Anatomy, Center for Genetic Diseases, Chicago Medical School and School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Brandon Roman
- Department of Biological Sciences, DePaul University, Chicago, IL 60614, USA
| | | | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA 92010, USA
| | - Robert A Marr
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Eric M Norstrom
- Department of Biological Sciences, DePaul University, Chicago, IL 60614, USA
| | - Michelle L Hastings
- Department of Cell Biology and Anatomy, Center for Genetic Diseases, Chicago Medical School and School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA.
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57
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Laulagnier K, Javalet C, Hemming FJ, Chivet M, Lachenal G, Blot B, Chatellard C, Sadoul R. Amyloid precursor protein products concentrate in a subset of exosomes specifically endocytosed by neurons. Cell Mol Life Sci 2018; 75:757-773. [PMID: 28956068 PMCID: PMC11105273 DOI: 10.1007/s00018-017-2664-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 08/31/2017] [Accepted: 09/20/2017] [Indexed: 12/15/2022]
Abstract
Amyloid beta peptide (Aβ), the main component of senile plaques of Alzheimer's disease brains, is produced by sequential cleavage of amyloid precursor protein (APP) and of its C-terminal fragments (CTFs). An unanswered question is how amyloidogenic peptides spread throughout the brain during the course of the disease. Here, we show that small lipid vesicles called exosomes, secreted in the extracellular milieu by cortical neurons, carry endogenous APP and are strikingly enriched in CTF-α and the newly characterized CTF-η. Exosomes from N2a cells expressing human APP with the autosomal dominant Swedish mutation contain Aβ peptides as well as CTF-α and CTF-η, while those from cells expressing the non-mutated form of APP only contain CTF-α and CTF-η. APP and CTFs are sorted into a subset of exosomes which lack the tetraspanin CD63 and specifically bind to dendrites of neurons, unlike exosomes carrying CD63 which bind to both neurons and glial cells. Thus, neuroblastoma cells secrete distinct populations of exosomes carrying different cargoes and targeting specific cell types. APP-carrying exosomes can be endocytosed by receiving cells, allowing the processing of APP acquired by exosomes to give rise to the APP intracellular domain (AICD). Thus, our results show for the first time that neuronal exosomes may indeed act as vehicles for the intercellular transport of APP and its catabolites.
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Affiliation(s)
- Karine Laulagnier
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France.
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France.
| | - Charlotte Javalet
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France
| | - Fiona J Hemming
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France
| | - Mathilde Chivet
- Dulbecco Telethon Institute Lab of Neurodegenerative Diseases, Centre for Integrative Biology (CIBIO), University of Trento, 38123, Trento, Italy
| | - Gaëlle Lachenal
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France
| | - Béatrice Blot
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France
| | - Christine Chatellard
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France
| | - Rémy Sadoul
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, 38042, Grenoble, France.
- Institut des Neurosciences, Université Grenoble Alpes, 38042, Grenoble, France.
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58
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Azevedo PO, Lousado L, Paiva AE, Andreotti JP, Santos GSP, Sena IFG, Prazeres PHDM, Filev R, Mintz A, Birbrair A. Endothelial cells maintain neural stem cells quiescent in their niche. Neuroscience 2017; 363:62-65. [PMID: 28893649 PMCID: PMC6089873 DOI: 10.1016/j.neuroscience.2017.08.059] [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: 08/09/2017] [Revised: 08/24/2017] [Accepted: 08/31/2017] [Indexed: 01/02/2023]
Abstract
Niches are specialized microenvironments that regulate stem cells' activity. The neural stem cell (NSC) niche defines a zone in which NSCs are retained and produce new cells of the nervous system throughout life. Understanding the signaling mechanisms by which the niche controls the NSC fate is crucial for the success of clinical applications. In a recent study, Sato and colleagues, by using state-of-the-art techniques, including sophisticated in vivo lineage-tracing technologies, provide evidence that endothelial amyloid precursor protein (APP) is an important component of the NSC niche. Strikingly, depletion of APP increased NSC proliferation in the subventricular zone, indicating that endothelial cells negatively regulate NSCs' growth. The emerging knowledge from this research will be important for the treatment of several neurological diseases.
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Affiliation(s)
- Patrick O Azevedo
- Department of Pathology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Luiza Lousado
- Department of Pathology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ana E Paiva
- Department of Pathology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Julia P Andreotti
- Department of Pathology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Gabryella S P Santos
- Department of Pathology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Isadora F G Sena
- Department of Pathology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Pedro H D M Prazeres
- Department of Pathology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Renato Filev
- Laboratory of Neurobiology, Federal University of São Paulo, SP, Brazil
| | - Akiva Mintz
- Department of Radiology, Columbia University Medical Center, New York, NY, USA
| | - Alexander Birbrair
- Department of Pathology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil; Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY, USA; Ruth L. and David S. Gottesman Institute for Stem Cell and Regenerative Medicine Research, Albert Einstein College of Medicine, Bronx, NY, USA.
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59
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Langosch D, Steiner H. Substrate processing in intramembrane proteolysis by γ-secretase - the role of protein dynamics. Biol Chem 2017; 398:441-453. [PMID: 27845877 DOI: 10.1515/hsz-2016-0269] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 11/08/2016] [Indexed: 01/31/2023]
Abstract
Intramembrane proteases comprise a number of different membrane proteins with different types of catalytic sites. Their common denominator is cleavage within the plane of the membrane, which usually results in peptide bond scission within the transmembrane helices of their substrates. Despite recent progress in the determination of high-resolution structures, as illustrated here for the γ-secretase complex and its substrate C99, it is still unknown how these enzymes function and how they distinguish between substrates and non-substrates. In principle, substrate/non-substrate discrimination could occur at the level of substrate binding and/or cleavage. Focusing on the γ-secretase/C99 pair, we will discuss recent observations suggesting that global motions within a substrate transmembrane helix may be much more important for defining a substrate than local unraveling at cleavage sites.
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60
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Fu W, Vukojevic V, Patel A, Soudy R, MacTavish D, Westaway D, Kaur K, Goncharuk V, Jhamandas J. Role of microglial amylin receptors in mediating beta amyloid (Aβ)-induced inflammation. J Neuroinflammation 2017; 14:199. [PMID: 28985759 PMCID: PMC5639602 DOI: 10.1186/s12974-017-0972-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 09/27/2017] [Indexed: 02/06/2023] Open
Abstract
Background Neuroinflammation in the brain consequent to activation of microglia is viewed as an important component of Alzheimer’s disease (AD) pathology. Amyloid beta (Aβ) protein is known to activate microglia and unleash an inflammatory cascade that eventually results in neuronal dysfunction and death. In this study, we sought to identify the presence of amylin receptors on human fetal and murine microglia and determine whether Aβ activation of the inflammasome complex and subsequent release of cytokines is mediated through these receptors. Methods The presence of dimeric components of the amylin receptor (calcitonin receptor and receptor activity modifying protein 3) were first immunohistochemically identified on microglia. Purified human fetal microglial (HFM) cultures were incubated with an in vivo microglial marker, DyLight 594-conjugated tomato lectin, and loaded with the membrane-permeant green fluorescent dye, Fluo-8L-AM for measurements of intracellular calcium [Ca2+]i. HFM and BV-2 cells were primed with lipopolysaccharide and then exposed to either human amylin or soluble oligomeric Aβ1–42 prior to treatment with and without the amylin receptor antagonist, AC253. Changes in the inflammasome complex, NLRP3 and caspase-1, were examined in treated cell cultures with Western blot and fluorometric assays. RT-PCR measurements were performed to assess cytokine release. Finally, in vivo studies were performed in transgenic mouse model of AD (5xFAD) to examine the effects of systemic administration of AC253 on markers of neuroinflammation in the brain. Results Acute applications of human amylin or Aβ1–42 resulted in an increase in [Ca2+]i that could be blocked by the amylin receptor antagonist, AC253. Activation of the NLRP3 and caspase-1 and subsequent release of cytokines, TNFα and IL-1β, was diminished by AC253 pretreatment of HFMs and BV2 cells. In vivo, intraperitoneal administration of AC253 resulted in a reduction in microglial markers (Iba-1 and CD68), caspase-1, TNFα, and IL-1β. These reductions in inflammatory markers were accompanied by reduction in amyloid plaque and size in the brains of 5xFAD mice compared to controls. Conclusion Microglial amylin receptors mediate Aβ-evoked inflammation, and amylin receptor antagonists therefore offer an attractive therapeutic target for intervention in AD. Electronic supplementary material The online version of this article (10.1186/s12974-017-0972-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wen Fu
- Department of Medicine (Neurology), Neuroscience and Mental Health Institute, University of Alberta, 530 Heritage Medical Research Centre, Edmonton, AB, T6G 2S2, Canada
| | - Vlatka Vukojevic
- Department of Medicine (Neurology), Neuroscience and Mental Health Institute, University of Alberta, 530 Heritage Medical Research Centre, Edmonton, AB, T6G 2S2, Canada
| | - Aarti Patel
- Department of Medicine (Neurology), Neuroscience and Mental Health Institute, University of Alberta, 530 Heritage Medical Research Centre, Edmonton, AB, T6G 2S2, Canada
| | - Rania Soudy
- Department of Medicine (Neurology), Neuroscience and Mental Health Institute, University of Alberta, 530 Heritage Medical Research Centre, Edmonton, AB, T6G 2S2, Canada.,Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - David MacTavish
- Department of Medicine (Neurology), Neuroscience and Mental Health Institute, University of Alberta, 530 Heritage Medical Research Centre, Edmonton, AB, T6G 2S2, Canada
| | - David Westaway
- Department of Medicine (Neurology), Neuroscience and Mental Health Institute, University of Alberta, 530 Heritage Medical Research Centre, Edmonton, AB, T6G 2S2, Canada.,Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.,Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB, Canada
| | - Kamaljit Kaur
- Chapman University School of Pharmacy, Irvine, CA, USA
| | | | - Jack Jhamandas
- Department of Medicine (Neurology), Neuroscience and Mental Health Institute, University of Alberta, 530 Heritage Medical Research Centre, Edmonton, AB, T6G 2S2, Canada.
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61
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William Rebeck G, Pak DTS. A mobile APP for sharing contacts on your cell: An Editorial Highlight for 'The physiological role of the amyloid precursor protein as an adhesion molecule in the developing nervous system' on page 11. J Neurochem 2017; 143:9-10. [PMID: 28809040 DOI: 10.1111/jnc.14115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 06/25/2017] [Indexed: 12/14/2022]
Abstract
The Review highlighted in this Editorial followed a CAEN Return Home Grant.
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Affiliation(s)
- George William Rebeck
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC, USA
| | - Daniel T S Pak
- Department of Pharmacology & Physiology, Georgetown University Medical Center, Washington, DC, USA
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62
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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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63
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Platelet amyloid precursor protein is a modulator of venous thromboembolism in mice. Blood 2017; 130:527-536. [DOI: 10.1182/blood-2017-01-764910] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 06/08/2017] [Indexed: 10/19/2022] Open
Abstract
Key Points
APP is dispensable for platelet activation and arterial thrombosis. APP is an important novel regulator of vein thrombosis and controls coagulation and neutrophil extracellular traps formation.
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Manduca Contactin Regulates Amyloid Precursor Protein-Dependent Neuronal Migration. J Neurosci 2017; 36:8757-75. [PMID: 27535920 DOI: 10.1523/jneurosci.0729-16.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 07/12/2016] [Indexed: 01/06/2023] Open
Abstract
UNLABELLED Amyloid precursor protein (APP) was originally identified as the source of β-amyloid peptides that accumulate in Alzheimer's disease (AD), but it also has been implicated in the control of multiple aspects of neuronal motility. APP belongs to an evolutionarily conserved family of transmembrane proteins that can interact with a variety of adapter and signaling molecules. Recently, we showed that both APP and its insect ortholog [APPL (APP-Like)] directly bind the heterotrimeric G-protein Goα, supporting the model that APP can function as an unconventional Goα-coupled receptor. We also adapted a well characterized assay of neuronal migration in the hawkmoth, Manduca sexta, to show that APPL-Goα signaling restricts ectopic growth within the developing nervous system, analogous to the role postulated for APP family proteins in controlling migration within the mammalian cortex. Using this assay, we have now identified Manduca Contactin (MsContactin) as an endogenous ligand for APPL, consistent with previous work showing that Contactins interact with APP family proteins in other systems. Using antisense-based knockdown protocols and fusion proteins targeting both proteins, we have shown that MsContactin is selectively expressed by glial cells that ensheath the migratory neurons (expressing APPL), and that MsContactin-APPL interactions normally prevent inappropriate migration and outgrowth. These results provide new evidence that Contactins can function as authentic ligands for APP family proteins that regulate APP-dependent responses in the developing nervous system. They also support the model that misregulated Contactin-APP interactions might provoke aberrant activation of Goα and its effectors, thereby contributing to the neurodegenerative sequelae that typify AD. SIGNIFICANCE STATEMENT Members of the amyloid precursor protein (APP) family participate in many aspects of neuronal development, but the ligands that normally activate APP signaling have remained controversial. This research provides new evidence that members of the Contactin family function as authentic ligands for APP and its orthologs, and that this evolutionarily conserved class of membrane-attached proteins regulates key aspects of APP-dependent migration and outgrowth in the embryonic nervous system. By defining the normal role of Contactin-APP signaling during development, these studies also provide the framework for investigating how the misregulation of Contactin-APP interactions might contribute to neuronal dysfunction in the context of both normal aging and neurodegenerative conditions, including Alzheimer's disease.
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Puzzo D, Piacentini R, Fá M, Gulisano W, Li Puma DD, Staniszewski A, Zhang H, Tropea MR, Cocco S, Palmeri A, Fraser P, D'Adamio L, Grassi C, Arancio O. LTP and memory impairment caused by extracellular Aβ and Tau oligomers is APP-dependent. eLife 2017; 6. [PMID: 28696204 PMCID: PMC5529106 DOI: 10.7554/elife.26991] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/10/2017] [Indexed: 12/21/2022] Open
Abstract
The concurrent application of subtoxic doses of soluble oligomeric forms of human amyloid-beta (oAβ) and Tau (oTau) proteins impairs memory and its electrophysiological surrogate long-term potentiation (LTP), effects that may be mediated by intra-neuronal oligomers uptake. Intrigued by these findings, we investigated whether oAβ and oTau share a common mechanism when they impair memory and LTP in mice. We found that as already shown for oAβ, also oTau can bind to amyloid precursor protein (APP). Moreover, efficient intra-neuronal uptake of oAβ and oTau requires expression of APP. Finally, the toxic effect of both extracellular oAβ and oTau on memory and LTP is dependent upon APP since APP-KO mice were resistant to oAβ- and oTau-induced defects in spatial/associative memory and LTP. Thus, APP might serve as a common therapeutic target against Alzheimer's Disease (AD) and a host of other neurodegenerative diseases characterized by abnormal levels of Aβ and/or Tau. DOI:http://dx.doi.org/10.7554/eLife.26991.001
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Affiliation(s)
- Daniela Puzzo
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Roberto Piacentini
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Mauro Fá
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, United States
| | - Walter Gulisano
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Domenica D Li Puma
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Agnes Staniszewski
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, United States
| | - Hong Zhang
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, United States
| | - Maria Rosaria Tropea
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Sara Cocco
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Agostino Palmeri
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Paul Fraser
- Tanz Centre for Research in Neurodegenerative Diseases and Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - Luciano D'Adamio
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, United States
| | - Claudio Grassi
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Ottavio Arancio
- Department of Pathology and Cell Biology and Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New york, United States
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Amylin Receptor: A Potential Therapeutic Target for Alzheimer's Disease. Trends Mol Med 2017; 23:709-720. [PMID: 28694141 DOI: 10.1016/j.molmed.2017.06.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 06/08/2017] [Accepted: 06/14/2017] [Indexed: 01/29/2023]
Abstract
Alzheimer'sdisease (AD) is a progressive neurodegenerative disorder, characterized by senile plaques constituting extracellular deposits of β-amyloid (Aβ) fibrils. Since Aβ accumulation in the brain is considered an early event preceding, by decades, cognitive dysfunction, disease-modifying treatments are aimed at facilitating clearance of this protein from the brain or ameliorating its toxic effects. Recent studies have identified the amylin receptor as a capable mediator of the deleterious actions of Aβ and furthermore, administration of amylin receptor-based peptides has been shown to improve spatial memory and learning in transgenic mouse models of AD. Here, by discussing available evidence, we posit that the amylin receptor could be considered a potential therapeutic target for AD, and present the rationale for using amylin receptor antagonists to treat this debilitating condition.
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Zhang F, Gannon M, Chen Y, Zhou L, Jiao K, Wang Q. The amyloid precursor protein modulates α 2A-adrenergic receptor endocytosis and signaling through disrupting arrestin 3 recruitment. FASEB J 2017. [PMID: 28646018 DOI: 10.1096/fj.201700346r] [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] [Indexed: 12/12/2022]
Abstract
The amyloid precursor protein (APP) has long been appreciated for its role in Alzheimer's disease (AD) pathology. However, less is known about the physiologic function of APP outside of AD. Particularly, whether and how APP may regulate functions of cell surface receptors, including GPCRs, remains largely unclear. In this study, we identified a novel direct interaction between APP and the α2A-adrenergic receptor (α2AAR) that occurs at the intracellular domains of both proteins. The APP interaction with α2AAR is promoted by agonist stimulation and competes with arrestin 3 binding to the receptor. Consequently, the presence of APP attenuates α2AAR internalization and desensitization, which are arrestin-dependent processes. Furthermore, in neuroblastoma neuro-2A cells and primary superior cervical ganglion neurons, where APP is highly expressed, the lack of APP leads to a dramatic increase in plasma membrane recruitment of endogenous arrestin 3 following α2AAR activation. Concomitantly, agonist-induced internalization of α2AAR is significantly enhanced in these neuronal cells. Our study provided the first evidence that APP fine tunes GPCR signaling and trafficking. Given the important role of α2AAR in controlling norepinephrine release and response, this novel regulation of α2AAR by APP may have an impact on modulation of noradrenergic activity and sympathetic tone.-Zhang, F., Gannon, M., Chen, Y., Zhou, L., Jiao, K., Wang, Q. The amyloid precursor protein modulates α2A-adrenergic receptor endocytosis and signaling through disrupting arrestin 3 recruitment.
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Affiliation(s)
- Fang Zhang
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Mary Gannon
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Yunjia Chen
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Lufang Zhou
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Kai Jiao
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Qin Wang
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA;
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Montagna E, Dorostkar MM, Herms J. The Role of APP in Structural Spine Plasticity. Front Mol Neurosci 2017; 10:136. [PMID: 28539872 PMCID: PMC5423954 DOI: 10.3389/fnmol.2017.00136] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/21/2017] [Indexed: 11/15/2022] Open
Abstract
Amyloid precursor protein (APP) is a transmembrane protein highly expressed in neurons. The full-length protein has cell-adhesion and receptor-like properties, which play roles in synapse formation and stability. Furthermore, APP can be cleaved by several proteases into numerous fragments, many of which affect synaptic function and stability. This review article focuses on the mechanisms of APP in structural spine plasticity, which encompasses the morphological alterations at excitatory synapses. These occur as changes in the number and morphology of dendritic spines, which correspond to the postsynaptic compartment of excitatory synapses. Both overexpression and knockout (KO) of APP lead to impaired synaptic plasticity. Recent data also suggest a role of APP in the regulation of astrocytic D-serine homeostasis, which in turn regulates synaptic plasticity.
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Affiliation(s)
- Elena Montagna
- Department for Translational Brain Research, German Center for Neurodegenerative Diseases (DZNE), Ludwig-Maximilian-University MunichMunich, Germany
| | - Mario M Dorostkar
- Center for Neuropathology and Prion Research, Ludwig-Maximilian-University MunichMunich, Germany
| | - Jochen Herms
- Department for Translational Brain Research, German Center for Neurodegenerative Diseases (DZNE), Ludwig-Maximilian-University MunichMunich, Germany.,Center for Neuropathology and Prion Research, Ludwig-Maximilian-University MunichMunich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Ludwig-Maximilian-University MunichMunich, Germany
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Chiarini A, Armato U, Liu D, Dal Prà I. Calcium-Sensing Receptor Antagonist NPS 2143 Restores Amyloid Precursor Protein Physiological Non-Amyloidogenic Processing in Aβ-Exposed Adult Human Astrocytes. Sci Rep 2017; 7:1277. [PMID: 28455519 PMCID: PMC5430644 DOI: 10.1038/s41598-017-01215-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 03/27/2017] [Indexed: 12/11/2022] Open
Abstract
Physiological non-amyloidogenic processing (NAP) of amyloid precursor holoprotein (hAPP) by α-secretases (e.g., ADAM10) extracellularly sheds neurotrophic/neuroprotective soluble (s)APPα and precludes amyloid-β peptides (Aβs) production via β-secretase amyloidogenic processing (AP). Evidence exists that Aβs interact with calcium-sensing receptors (CaSRs) in human astrocytes and neurons, driving the overrelease of toxic Aβ42/Aβ42-os (oligomers), which is completely blocked by CaSR antagonist (calcilytic) NPS 2143. Here, we investigated the mechanisms underlying NPS 2143 beneficial effects in human astrocytes. Moreover, because Alzheimer's disease (AD) involves neuroinflammation, we examined whether NPS 2143 remained beneficial when both fibrillary (f)Aβ25-35 and a microglial cytokine mixture (CMT) were present. Thus, hAPP NAP prevailed over AP in untreated astrocytes, which extracellularly shed all synthesized sAPPα while secreting basal Aβ40/42 amounts. Conversely, fAβ25-35 alone dramatically reduced sAPPα extracellular shedding while driving Aβ42/Aβ42-os oversecretion that CMT accelerated but not increased, despite a concurring hAPP overexpression. NPS 2143 promoted hAPP and ADAM10 translocation to the plasma membrane, thereby restoring sAPPα extracellular shedding and fully suppressing any Aβ42/Aβ42-os oversecretion, but left hAPP expression unaffected. Therefore, as anti-AD therapeutics calcilytics support neuronal viability by safeguarding astrocytes neurotrophic/neuroprotective sAPPα shedding, suppressing neurons and astrocytes Aβ42/Aβ42-os build-up/secretion, and remaining effective even under AD-typical neuroinflammatory conditions.
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Affiliation(s)
- Anna Chiarini
- Human Histology & Embryology Unit, Medical School, University of Verona, Verona, Venetia, Italy.
| | - Ubaldo Armato
- Human Histology & Embryology Unit, Medical School, University of Verona, Verona, Venetia, Italy
| | - Daisong Liu
- The Third Xiangya Hospital of Central South University, Department of Plastic Surgery, Changsha, Hunan, China
| | - Ilaria Dal Prà
- Human Histology & Embryology Unit, Medical School, University of Verona, Verona, Venetia, Italy.
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70
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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: 387] [Impact Index Per Article: 55.3] [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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71
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Guénette S, Strecker P, Kins S. APP Protein Family Signaling at the Synapse: Insights from Intracellular APP-Binding Proteins. Front Mol Neurosci 2017; 10:87. [PMID: 28424586 PMCID: PMC5371672 DOI: 10.3389/fnmol.2017.00087] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 03/13/2017] [Indexed: 12/17/2022] Open
Abstract
Understanding the molecular mechanisms underlying amyloid precursor protein family (APP/APP-like proteins, APLP) function in the nervous system can be achieved by studying the APP/APLP interactome. In this review article, we focused on intracellular APP interacting proteins that bind the YENPTY internalization motif located in the last 15 amino acids of the C-terminal region. These proteins, which include X11/Munc-18-interacting proteins (Mints) and FE65/FE65Ls, represent APP cytosolic binding partners exhibiting different neuronal functions. A comparison of FE65 and APP family member mutant mice revealed a shared function for APP/FE65 protein family members in neurogenesis and neuronal positioning. Accumulating evidence also supports a role for membrane-associated APP/APLP proteins in synapse formation and function. Therefore, it is tempting to speculate that APP/APLP C-terminal interacting proteins transmit APP/APLP-dependent signals at the synapse. Herein, we compare our current knowledge of the synaptic phenotypes of APP/APLP mutant mice with those of mice lacking different APP/APLP interaction partners and discuss the possible downstream effects of APP-dependent FE65/FE65L or X11/Mint signaling on synaptic vesicle release, synaptic morphology and function. Given that the role of X11/Mint proteins at the synapse is well-established, we propose a model highlighting the role of FE65 protein family members for transduction of APP/APLP physiological function at the synapse.
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Affiliation(s)
| | - Paul Strecker
- Department of Biology, Division of Human Biology, University of KaiserslauternKaiserslautern, Germany
| | - Stefan Kins
- Department of Biology, Division of Human Biology, University of KaiserslauternKaiserslautern, Germany
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72
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Singh SK, Srivastav S, Yadav AK, Srikrishna S. Knockdown of APPL mimics transgenic Aβ induced neurodegenerative phenotypes in Drosophila. Neurosci Lett 2017; 648:8-13. [PMID: 28336338 DOI: 10.1016/j.neulet.2017.03.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Revised: 03/14/2017] [Accepted: 03/17/2017] [Indexed: 12/22/2022]
Abstract
A variety of Drosophila mutant lines have been established as potential disease-models to study various disease mechanisms including human neurodegenerative diseases like Alzheimer's disease (AD), Huntington's disease (HD) and Parkinson's disease (PD). The evolutionary conservation of APP (Amyloid Precursor Protein) and APPL (Amyloid Precursor Protein-Like) and the comparable detrimental effects caused by their metabolic products strongly implies the conservation of their normal physiological functions. In view of this milieu, a comparative analysis on the pattern of neurodegenerative phenotypes between Drosophila APPL-RNAi line and transgenic Drosophila line expressing eye tissue specific human Aβ (Amyloid beta) was undertaken. Our results clearly show that Drosophila APPL-RNAi largely mimics transgenic Aβ in various phenotypes which include eye degeneration, reduced longevity and motor neuron deficit functions, etc. The ultra-structural morphological pattern of eye degeneration was confirmed by scanning electron microscopy. Further, a comparative study on longevity and motor behaviour between Aβ expressing and APPL knockdown lines revealed similar kind of behavioural deficit and longevity phenotypes. Therefore, it is suggested that APPL-knockdown approach can be used as an alternative approach to study neurodegenerative diseases in the fly model. To the best of our knowledge this is the first report showing comparable phenotypes between APPL and Aβ in AD model of Drosophila.
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Affiliation(s)
- Sandeep Kumar Singh
- Cancer and Neurobiology Laboratory, Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Saurabh Srivastav
- Cancer and Neurobiology Laboratory, Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Amarish Kumar Yadav
- Cancer and Neurobiology Laboratory, Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Saripella Srikrishna
- Cancer and Neurobiology Laboratory, Department of Biochemistry, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
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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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Xiong M, Jones OD, Peppercorn K, Ohline SM, Tate WP, Abraham WC. Secreted amyloid precursor protein-alpha can restore novel object location memory and hippocampal LTP in aged rats. Neurobiol Learn Mem 2017; 138:291-299. [DOI: 10.1016/j.nlm.2016.08.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/27/2016] [Accepted: 08/08/2016] [Indexed: 12/12/2022]
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Copenhaver PF, Kögel D. Role of APP Interactions with Heterotrimeric G Proteins: Physiological Functions and Pathological Consequences. Front Mol Neurosci 2017; 10:3. [PMID: 28197070 PMCID: PMC5281615 DOI: 10.3389/fnmol.2017.00003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 01/05/2017] [Indexed: 12/27/2022] Open
Abstract
Following the discovery that the amyloid precursor protein (APP) is the source of β-amyloid peptides (Aβ) that accumulate in Alzheimer’s disease (AD), structural analyses suggested that the holoprotein resembles a transmembrane receptor. Initial studies using reconstituted membranes demonstrated that APP can directly interact with the heterotrimeric G protein Gαo (but not other G proteins) via an evolutionarily G protein-binding motif in its cytoplasmic domain. Subsequent investigations in cell culture showed that antibodies against the extracellular domain of APP could stimulate Gαo activity, presumably mimicking endogenous APP ligands. In addition, chronically activating wild type APP or overexpressing mutant APP isoforms linked with familial AD could provoke Go-dependent neurotoxic responses, while biochemical assays using human brain samples suggested that the endogenous APP-Go interactions are perturbed in AD patients. More recently, several G protein-dependent pathways have been implicated in the physiological roles of APP, coupled with evidence that APP interacts both physically and functionally with Gαo in a variety of contexts. Work in insect models has demonstrated that the APP ortholog APPL directly interacts with Gαo in motile neurons, whereby APPL-Gαo signaling regulates the response of migratory neurons to ligands encountered in the developing nervous system. Concurrent studies using cultured mammalian neurons and organotypic hippocampal slice preparations have shown that APP signaling transduces the neuroprotective effects of soluble sAPPα fragments via modulation of the PI3K/Akt pathway, providing a mechanism for integrating the stress and survival responses regulated by APP. Notably, this effect was also inhibited by pertussis toxin, indicating an essential role for Gαo/i proteins. Unexpectedly, C-terminal fragments (CTFs) derived from APP have also been found to interact with Gαs, whereby CTF-Gαs signaling can promote neurite outgrowth via adenylyl cyclase/PKA-dependent pathways. These reports offer the intriguing perspective that G protein switching might modulate APP-dependent responses in a context-dependent manner. In this review, we provide an up-to-date perspective on the model that APP plays a variety of roles as an atypical G protein-coupled receptor in both the developing and adult nervous system, and we discuss the hypothesis that disruption of these normal functions might contribute to the progressive neuropathologies that typify AD.
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Affiliation(s)
- Philip F Copenhaver
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Sciences University, Portland OR, USA
| | - Donat Kögel
- Experimental Neurosurgery, Goethe University Frankfurt Frankfurt am Main, Germany
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Salminen A, Kauppinen A, Kaarniranta K. Hypoxia/ischemia activate processing of Amyloid Precursor Protein: impact of vascular dysfunction in the pathogenesis of Alzheimer's disease. J Neurochem 2017; 140:536-549. [DOI: 10.1111/jnc.13932] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/05/2016] [Accepted: 12/10/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Antero Salminen
- Department of Neurology; Institute of Clinical Medicine; University of Eastern Finland; Kuopio Finland
| | - Anu Kauppinen
- School of Pharmacy; Faculty of Health Sciences; University of Eastern Finland; Kuopio Finland
| | - Kai Kaarniranta
- Department of Ophthalmology; Institute of Clinical Medicine; University of Eastern Finland; Kuopio Finland
- Department of Ophthalmology; Kuopio University Hospital; Kuopio Finland
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Hooper C, De Souto Barreto P, Payoux P, Salabert AS, Guyonnet S, Andrieu S, Sourdet S, Delrieu J, Vellas B. Association of Cortical β-Amyloid with Erythrocyte Membrane Monounsaturated and Saturated Fatty Acids in Older Adults at Risk of Dementia. J Nutr Health Aging 2017; 21:1170-1175. [PMID: 29188876 DOI: 10.1007/s12603-017-0975-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVES We examined the relationships between erythrocyte membrane monounsaturated fatty acids (MUFAs) and saturated fatty acids (SFAs) and cortical β-amyloid (Aβ) load in older adults reporting subjective memory complaints. DESIGN This is a cross-sectional study using data from the Multidomain Alzheimer Preventive Trial (MAPT); a randomised controlled trial. SETTING French community dwellers aged 70 or over reporting subjective memory complaints, but free from a diagnosis of clinical dementia. PARTICIPANTS Participants of this study were 61 individuals from the placebo arm of the MAPT trial with data on erythrocyte membrane fatty acid levels and cortical Aβ load. MEASUREMENTS Cortical-to-cerebellar standard uptake value ratios were assessed using [18F] florbetapir positron emission tomography (PET). Fatty acids were measured in erythrocyte cell membranes using gas chromatography. Associations between erythrocyte membrane MUFAs and SFAs and cortical Aβ load were explored using adjusted multiple linear regression models and were considered significant at p ≤ 0.005 (10 comparisons) after correction for multiple testing. RESULTS We found no significant associations between fatty acids and cortical Aβ load using multiple linear regression adjusted for age, sex, education, cognition, PET-scan to clinical assessment interval, PET-scan to blood collection interval and apolipoprotein E (ApoE) status. The association closest to significance was that between erythrocyte membrane stearic acid and Aβ (B-coefficient 0.03, 95 % CI: 0.00,0.05, p = 0.05). This association, although statistically non-significant, appeared to be stronger amongst ApoE ε4 carriers (B-coefficient 0.04, 95 % CI: -0.01,0.09, p = 0.08) compared to ApoE ε4 non-carriers (B-coefficient 0.02, 95 % CI: -0.01,0.05, p = 0.18) in age and sex stratified analysis. CONCLUSION Future research in the form of large longitudinal observational study is needed to validate our findings, particularly regarding the potential association of stearic acid with cortical Aβ.
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Affiliation(s)
- C Hooper
- Claudie Hooper, Gérontopôle, Department of Geriatrics, CHU Toulouse, Purpan University Hospital, Toulouse, France. , Tel : +33 (5) 61 77 64 25, Fax : +33 (5) 61 77 64 75
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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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Cassar M, Kretzschmar D. Analysis of Amyloid Precursor Protein Function in Drosophila melanogaster. Front Mol Neurosci 2016; 9:61. [PMID: 27507933 PMCID: PMC4960247 DOI: 10.3389/fnmol.2016.00061] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 07/13/2016] [Indexed: 01/10/2023] Open
Abstract
The Amyloid precursor protein (APP) has mainly been investigated in connection with its role in Alzheimer’s Disease (AD) due to its cleavage resulting in the production of the Aβ peptides that accumulate in the plaques characteristic for this disease. However, APP is an evolutionary conserved protein that is not only found in humans but also in many other species, including Drosophila, suggesting an important physiological function. Besides Aβ, several other fragments are produced by the cleavage of APP; large secreted fragments derived from the N-terminus and a small intracellular C-terminal fragment. Although these fragments have received much less attention than Aβ, a picture about their function is finally emerging. In contrast to mammals, which express three APP family members, Drosophila expresses only one APP protein called APP-like or APPL. Therefore APPL functions can be studied in flies without the complication that other APP family members may have redundant functions. Flies lacking APPL are viable but show defects in neuronal outgrowth in the central and peripheral nervous system (PNS) in addition to synaptic changes. Furthermore, APPL has been connected with axonal transport functions. In the adult nervous system, APPL, and more specifically its secreted fragments, can protect neurons from degeneration. APPL cleavage also prevents glial death. Lastly, APPL was found to be involved in behavioral deficits and in regulating sleep/activity patterns. This review, will describe the role of APPL in neuronal development and maintenance and briefly touch on its emerging function in circadian rhythms while an accompanying review will focus on its role in learning and memory formation.
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Affiliation(s)
- 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
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80
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Bock HH, May P. Canonical and Non-canonical Reelin Signaling. Front Cell Neurosci 2016; 10:166. [PMID: 27445693 PMCID: PMC4928174 DOI: 10.3389/fncel.2016.00166] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 06/08/2016] [Indexed: 12/11/2022] Open
Abstract
Reelin is a large secreted glycoprotein that is essential for correct neuronal positioning during neurodevelopment and is important for synaptic plasticity in the mature brain. Moreover, Reelin is expressed in many extraneuronal tissues; yet the roles of peripheral Reelin are largely unknown. In the brain, many of Reelin's functions are mediated by a molecular signaling cascade that involves two lipoprotein receptors, apolipoprotein E receptor-2 (Apoer2) and very low density-lipoprotein receptor (Vldlr), the neuronal phosphoprotein Disabled-1 (Dab1), and members of the Src family of protein tyrosine kinases as crucial elements. This core signaling pathway in turn modulates the activity of adaptor proteins and downstream protein kinase cascades, many of which target the neuronal cytoskeleton. However, additional Reelin-binding receptors have been postulated or described, either as coreceptors that are essential for the activation of the "canonical" Reelin signaling cascade involving Apoer2/Vldlr and Dab1, or as receptors that activate alternative or additional signaling pathways. Here we will give an overview of canonical and alternative Reelin signaling pathways, molecular mechanisms involved, and their potential physiological roles in the context of different biological settings.
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Affiliation(s)
- Hans H Bock
- Clinic of Gastroenterology and Hepatology, Heinrich-Heine-University Düsseldorf Düsseldorf, Germany
| | - Petra May
- Clinic of Gastroenterology and Hepatology, Heinrich-Heine-University Düsseldorf Düsseldorf, Germany
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81
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Deyts C, Clutter M, Herrera S, Jovanovic N, Goddi A, Parent AT. Loss of presenilin function is associated with a selective gain of APP function. eLife 2016; 5. [PMID: 27196744 PMCID: PMC4915812 DOI: 10.7554/elife.15645] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 05/18/2016] [Indexed: 12/12/2022] Open
Abstract
Presenilin 1 (PS1) is an essential γ-secretase component, the enzyme responsible for amyloid precursor protein (APP) intramembraneous cleavage. Mutations in PS1 lead to dominant-inheritance of early-onset familial Alzheimer’s disease (FAD). Although expression of FAD-linked PS1 mutations enhances toxic Aβ production, the importance of other APP metabolites and γ-secretase substrates in the etiology of the disease has not been confirmed. We report that neurons expressing FAD-linked PS1 variants or functionally deficient PS1 exhibit enhanced axodendritic outgrowth due to increased levels of APP intracellular C-terminal fragment (APP-CTF). APP expression is required for exuberant neurite outgrowth and hippocampal axonal sprouting observed in knock-in mice expressing FAD-linked PS1 mutation. APP-CTF accumulation initiates CREB signaling cascade through an association of APP-CTF with Gαs protein. We demonstrate that pathological PS1 loss-of-function impinges on neurite formation through a selective APP gain-of-function that could impact on axodendritic connectivity and contribute to aberrant axonal sprouting observed in AD patients. DOI:http://dx.doi.org/10.7554/eLife.15645.001 One of the hallmarks of Alzheimer’s disease is the accumulation within the brain of sticky deposits called plaques. These plaques form from clumps of molecules called amyloid-beta peptide. An enzyme called gamma-secretase generates the amyloid-beta peptide, by cutting it from a membrane-associated protein called APP. This enzyme consists of multiple subunits, and a mutation in one of these – presenilin-1 – causes a particularly severe form of Alzheimer’s disease. For decades, research into Alzheimer’s disease has focused on the harmful effects of amyloid-beta peptides and plaques. However, Deyts et al. now argue that the protein that gives rise to amyloid-beta peptides has a more direct role in Alzheimer’s disease than previously thought. Specifically, APP may contribute to the harmful effects of the presenilin-1 mutations. By studying genetically modified mice carrying a human presenilin-1 mutation, Deyts et al. show that some of these animals’ nerve cells grow abnormally. Their cell bodies sprout too many branches, while their nerve fibers – which carry electrical signals away from the cell body – become too long. These abnormalities resemble changes seen in the brain in Alzheimer’s disease. Unexpectedly, however, deleting the gene for APP in the presenilin-1 mutant mice prevents the changes from occurring. This suggests that APP must be present for the presenilin-1 mutation to exert this unwanted effect. An increase in APP-driven signaling within cells seems to trigger the observed abnormalities in nerve cells. The presenilin-1 mutation modifies how gamma-secretase cuts APP at the cell membrane to produce amyloid-beta peptides. This frees up the APP to instead interact with signaling cascades inside the cell. Given that gamma-secretase is a key therapeutic target in Alzheimer’s disease, further work is needed to explore the implications of these protein interactions for potential treatments. DOI:http://dx.doi.org/10.7554/eLife.15645.002
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Affiliation(s)
- Carole Deyts
- Departments of Neurobiology, The University of Chicago, Chicago, United States
| | - Mary Clutter
- Departments of Neurobiology, The University of Chicago, Chicago, United States
| | - Stacy Herrera
- Departments of Neurobiology, The University of Chicago, Chicago, United States
| | - Natalia Jovanovic
- Departments of Neurobiology, The University of Chicago, Chicago, United States
| | - Anna Goddi
- Departments of Neurobiology, The University of Chicago, Chicago, United States
| | - Angèle T Parent
- Departments of Neurobiology, The University of Chicago, Chicago, United States
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