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Fan J, Wei X, Dong H, Zhang Y, Zhou Y, Xu M, Xiao G. Advancement in Analytical Techniques for Determining the Activity of β-Site Amyloid Precursor Protein Cleaving Enzyme 1. Crit Rev Anal Chem 2022; 54:1797-1809. [PMID: 36227582 DOI: 10.1080/10408347.2022.2132812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Alzheimer's disease (AD) is a degenerative disease of the central nervous system. The pathogenesis is still not fully clear. One of the main histopathological manifestations is senile plaques formed by β-amyloid (Aβ) accumulation. Aβ is generated from the sequential proteolysis of amyloid precursor protein (APP) by β-secretase [i.e. β-site APP cleaving enzyme 1 (BACE1)] and γ-secretase, with a rate-limiting step controlled by BACE1 activity. Therefore, inhibiting BACE1 activity has become a potential therapeutic strategy for AD. The development of reliable detection methods for BACE1 activity plays an important role in early diagnosis of AD and evaluation of the therapeutic effect of new drugs for AD. This article has reviewed the recent advances in BACE1 activity detection techniques. The challenges of applying these analysis techniques to early clinical diagnosis of AD and development trends of the detection techniques have been prospected.
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Affiliation(s)
- Jie Fan
- College of Materials Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, China
| | - Xiuhua Wei
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu, China
| | - Hui Dong
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu, China
| | - Yintang Zhang
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu, China
| | - Yanli Zhou
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu, China
| | - Maotian Xu
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu, China
| | - Guoqing Xiao
- College of Materials Science and Engineering, Xi'an University of Architecture and Technology, Xi'an, China
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Hampel H, Vassar R, De Strooper B, Hardy J, Willem M, Singh N, Zhou J, Yan R, Vanmechelen E, De Vos A, Nisticò R, Corbo M, Imbimbo BP, Streffer J, Voytyuk I, Timmers M, Tahami Monfared AA, Irizarry M, Albala B, Koyama A, Watanabe N, Kimura T, Yarenis L, Lista S, Kramer L, Vergallo A. The β-Secretase BACE1 in Alzheimer's Disease. Biol Psychiatry 2021; 89:745-756. [PMID: 32223911 PMCID: PMC7533042 DOI: 10.1016/j.biopsych.2020.02.001] [Citation(s) in RCA: 337] [Impact Index Per Article: 112.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 01/29/2020] [Accepted: 02/05/2020] [Indexed: 01/18/2023]
Abstract
BACE1 (beta-site amyloid precursor protein cleaving enzyme 1) was initially cloned and characterized in 1999. It is required for the generation of all monomeric forms of amyloid-β (Aβ), including Aβ42, which aggregates into bioactive conformational species and likely initiates toxicity in Alzheimer's disease (AD). BACE1 concentrations and rates of activity are increased in AD brains and body fluids, thereby supporting the hypothesis that BACE1 plays a critical role in AD pathophysiology. Therefore, BACE1 is a prime drug target for slowing down Aβ production in early AD. Besides the amyloidogenic pathway, BACE1 has other substrates that may be important for synaptic plasticity and synaptic homeostasis. Indeed, germline and adult conditional BACE1 knockout mice display complex neurological phenotypes. Despite BACE1 inhibitor clinical trials conducted so far being discontinued for futility or safety reasons, BACE1 remains a well-validated therapeutic target for AD. A safe and efficacious compound with high substrate selectivity as well as a more accurate dose regimen, patient population, and disease stage may yet be found. Further research should focus on the role of Aβ and BACE1 in physiological processes and key pathophysiological mechanisms of AD. The functions of BACE1 and the homologue BACE2, as well as the biology of Aβ in neurons and glia, deserve further investigation. Cellular and molecular studies of BACE1 and BACE2 knockout mice coupled with biomarker-based human research will help elucidate the biological functions of these important enzymes and identify their substrates and downstream effects. Such studies will have critical implications for BACE1 inhibition as a therapeutic approach for AD.
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Affiliation(s)
- Harald Hampel
- Neurology Business Group, Eisai Inc., Woodcliff Lake, New Jersey; Sorbonne University, GRC No. 21, Alzheimer Precision Medicine, Pitié-Salpêtrière Hospital, Paris, France.
| | - Robert Vassar
- Department of Neurology, Mesulam Center for Cognitive Neurology and Alzheimer's Disease, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Bart De Strooper
- Department of Neurosciences, KU Leuven, Leuven, Belgium; Centre for Brain and Disease Research, VIB (Flanders Institute for Biotechnology), Leuven, Belgium; Dementia Research Institute, University College London, London, United Kingdom
| | - John Hardy
- Department of Molecular Neuroscience and Reta Lilla Weston Laboratories, Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Michael Willem
- Chair of Metabolic Biochemistry, Biomedical Center, Faculty of Medicine, Ludwig Maximilians University Munich, Munich, Germany
| | - Neeraj Singh
- Department of Neuroscience, University of Connecticut Health, Farmington, Connecticut
| | - John Zhou
- Department of Neuroscience, University of Connecticut Health, Farmington, Connecticut
| | - Riqiang Yan
- Department of Neuroscience, University of Connecticut Health, Farmington, Connecticut
| | | | | | - Robert Nisticò
- Laboratory of Neuropharmacology, EBRI Rita Levi-Montalcini Foundation, Rome, Italy; School of Pharmacy, Department of Biology, University of Rome "Tor Vergata," Rome, Italy
| | - Massimo Corbo
- Department of Neurorehabilitation Sciences, Casa Cura Policlinico, Milan, Italy
| | | | - Johannes Streffer
- Reference Center for Biological Markers of Dementia, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium; UCB Biopharma SPRL, Braine-l'Alleud, Belgium
| | - Iryna Voytyuk
- Department of Neurosciences, KU Leuven, Leuven, Belgium; Centre for Brain and Disease Research, VIB (Flanders Institute for Biotechnology), Leuven, Belgium; ALBORADA Drug Discovery Institute, University of Cambridge, Cambridge, United Kingdom
| | - Maarten Timmers
- Reference Center for Biological Markers of Dementia, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium; Janssen Research and Development, a division of Janssen Pharmaceutica, Beerse, Belgium
| | - Amir Abbas Tahami Monfared
- Neurology Business Group, Eisai Inc., Woodcliff Lake, New Jersey; Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Quebec, Canada
| | - Michael Irizarry
- Neurology Business Group, Eisai Inc., Woodcliff Lake, New Jersey
| | - Bruce Albala
- Neurology Business Group, Eisai Inc., Woodcliff Lake, New Jersey
| | - Akihiko Koyama
- Neurology Business Group, Eisai Inc., Woodcliff Lake, New Jersey
| | | | | | - Lisa Yarenis
- Neurology Business Group, Eisai Inc., Woodcliff Lake, New Jersey
| | - Simone Lista
- Sorbonne University, GRC No. 21, Alzheimer Precision Medicine, Pitié-Salpêtrière Hospital, Paris, France; Institute of Memory and Alzheimer's Disease, Department of Neurology, Pitié-Salpêtrière Hospital, Paris, France; Brain & Spine Institute, INSERM U 1127, CNRS UMR 7225, Paris, France
| | - Lynn Kramer
- Neurology Business Group, Eisai Inc., Woodcliff Lake, New Jersey
| | - Andrea Vergallo
- Neurology Business Group, Eisai Inc., Woodcliff Lake, New Jersey; Sorbonne University, GRC No. 21, Alzheimer Precision Medicine, Pitié-Salpêtrière Hospital, Paris, France; Institute of Memory and Alzheimer's Disease, Department of Neurology, Pitié-Salpêtrière Hospital, Paris, France; Brain & Spine Institute, INSERM U 1127, CNRS UMR 7225, Paris, France.
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3
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Pedrero-Prieto CM, García-Carpintero S, Frontiñán-Rubio J, Llanos-González E, Aguilera García C, Alcaín FJ, Lindberg I, Durán-Prado M, Peinado JR, Rabanal-Ruiz Y. A comprehensive systematic review of CSF proteins and peptides that define Alzheimer's disease. Clin Proteomics 2020; 17:21. [PMID: 32518535 PMCID: PMC7273668 DOI: 10.1186/s12014-020-09276-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/09/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND During the last two decades, over 100 proteomics studies have identified a variety of potential biomarkers in CSF of Alzheimer's (AD) patients. Although several reviews have proposed specific biomarkers, to date, the statistical relevance of these proteins has not been investigated and no peptidomic analyses have been generated on the basis of specific up- or down- regulation. Herein, we perform an analysis of all unbiased explorative proteomics studies of CSF biomarkers in AD to critically evaluate whether proteins and peptides identified in each study are consistent in distribution; direction change; and significance, which would strengthen their potential use in studies of AD pathology and progression. METHODS We generated a database containing all CSF proteins whose levels are known to be significantly altered in human AD from 47 independent, validated, proteomics studies. Using this database, which contains 2022 AD and 2562 control human samples, we examined whether each protein is consistently present on the basis of reliable statistical studies; and if so, whether it is over- or under-represented in AD. Additionally, we performed a direct analysis of available mass spectrometric data of these proteins to generate an AD CSF peptide database with 3221 peptides for further analysis. RESULTS Of the 162 proteins that were identified in 2 or more studies, we investigated their enrichment or depletion in AD CSF. This allowed us to identify 23 proteins which were increased and 50 proteins which were decreased in AD, some of which have never been revealed as consistent AD biomarkers (i.e. SPRC or MUC18). Regarding the analysis of the tryptic peptide database, we identified 87 peptides corresponding to 13 proteins as the most highly consistently altered peptides in AD. Analysis of tryptic peptide fingerprinting revealed specific peptides encoded by CH3L1, VGF, SCG2, PCSK1N, FBLN3 and APOC2 with the highest probability of detection in AD. CONCLUSIONS Our study reveals a panel of 27 proteins and 21 peptides highly altered in AD with consistent statistical significance; this panel constitutes a potent tool for the classification and diagnosis of AD.
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Affiliation(s)
- Cristina M. Pedrero-Prieto
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, Regional Center for Biomedical Research, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Sonia García-Carpintero
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, Regional Center for Biomedical Research, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Javier Frontiñán-Rubio
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, Regional Center for Biomedical Research, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Emilio Llanos-González
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, Regional Center for Biomedical Research, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Cristina Aguilera García
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, Regional Center for Biomedical Research, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Francisco J. Alcaín
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, Regional Center for Biomedical Research, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201 USA
| | - Mario Durán-Prado
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, Regional Center for Biomedical Research, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Juan R. Peinado
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, Regional Center for Biomedical Research, University of Castilla-La Mancha, Ciudad Real, Spain
| | - Yoana Rabanal-Ruiz
- Department of Medical Sciences, Ciudad Real Medical School, Oxidative Stress and Neurodegeneration Group, Regional Center for Biomedical Research, University of Castilla-La Mancha, Ciudad Real, Spain
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4
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Barthet G, Mulle C. Presynaptic failure in Alzheimer's disease. Prog Neurobiol 2020; 194:101801. [PMID: 32428558 DOI: 10.1016/j.pneurobio.2020.101801] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/24/2020] [Accepted: 04/03/2020] [Indexed: 12/14/2022]
Abstract
Synaptic loss is the best correlate of cognitive deficits in Alzheimer's disease (AD). Extensive experimental evidence also indicates alterations of synaptic properties at the early stages of disease progression, before synapse loss and neuronal degeneration. A majority of studies in mouse models of AD have focused on post-synaptic mechanisms, including impairment of long-term plasticity, spine structure and glutamate receptor-mediated transmission. Here we review the literature indicating that the synaptic pathology in AD includes a strong presynaptic component. We describe the evidence indicating presynaptic physiological functions of the major molecular players in AD. These include the amyloid precursor protein (APP) and the two presenilin (PS) paralogs PS1 or PS2, genetically linked to the early-onset form of AD, in addition to tau which accumulates in a pathological form in the AD brain. Three main mechanisms participating in presynaptic functions are highlighted. APP fragments bind to presynaptic receptors (e.g. nAChRs and GABAB receptors), presenilins control Ca2+ homeostasis and Ca2+-sensors, and tau regulates the localization of presynaptic molecules and synaptic vesicles. We then discuss how impairment of these presynaptic physiological functions can explain or forecast the hallmarks of synaptic impairment and associated dysfunction of neuronal circuits in AD. Beyond the physiological roles of the AD-related proteins, studies in AD brains also support preferential presynaptic alteration. This review features presynaptic failure as a strong component of pathological mechanisms in AD.
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Affiliation(s)
- Gael Barthet
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, University of Bordeaux, France
| | - Christophe Mulle
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, University of Bordeaux, France.
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5
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Schauenburg L, Liebsch F, Eravci M, Mayer MC, Weise C, Multhaup G. APLP1 is endoproteolytically cleaved by γ-secretase without previous ectodomain shedding. Sci Rep 2018; 8:1916. [PMID: 29382944 PMCID: PMC5789831 DOI: 10.1038/s41598-018-19530-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 01/04/2018] [Indexed: 12/12/2022] Open
Abstract
Regulated intramembrane proteolysis of the amyloid precursor protein (APP) and its homologs, the APP like proteins APLP1 and APLP2, is typically a two-step process, which is initiated by ectodomain-shedding of the substrates by α- or β-secretases. Growing evidence, however, indicates that the cleavage process for APLP1 is different than for APP. Here, we describe that full-length APLP1, but not APP or APLP2, is uniquely cleaved by γ-secretase without previous ectodomain shedding. The new fragment, termed sAPLP1γ, was exclusively associated with APLP1, not APP, APLP2. We provide an exact molecular analysis showing that sAPLP1γ was uniquely generated by γ-secretase from full-length APLP1. Mass spectrometry analysis showed that the sAPLP1γ fragment and the longest Aβ-like peptide share the C-terminus. This novel mechanism of γ-secretase action is consistent with an ϵ-cut based upon the nature of the reaction in APP. We further demonstrate that the APLP1 transmembrane sequence is the critical determinant for γ-shedding and release of full-length APLP1. Moreover, the APLP1 TMS is sufficient to convert larger type-I membrane proteins like APP into direct γ-secretase substrates. Taken together, the direct cleavage of APLP1 is a novel feature of the γ-secretase prompting a re-thinking of γ-secretase activity modulation as a therapeutic strategy for Alzheimer disease.
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Affiliation(s)
- Linda Schauenburg
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany.,Sphingotec Therapeutics GmbH, Neuendorfstr. 15a, 16761, Hennigsdorf, Germany
| | - Filip Liebsch
- Department of Pharmacology & Therapeutics and Integrated Program in Neuroscience, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
| | - Murat Eravci
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Magnus C Mayer
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany.,Miltenyi Biotec GmbH, Robert-Koch-Strasse 1, 17166, Teterow, Germany
| | - Christoph Weise
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Gerhard Multhaup
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany. .,Department of Pharmacology & Therapeutics and Integrated Program in Neuroscience, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada.
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6
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Stoop MP, Runia TF, Stingl C, van der Vuurst de Vries RM, Luider TM, Hintzen RQ. Decreased Neuro-Axonal Proteins in CSF at First Attack of Suspected Multiple Sclerosis. Proteomics Clin Appl 2017; 11. [PMID: 28941200 DOI: 10.1002/prca.201700005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 08/23/2017] [Indexed: 01/10/2023]
Abstract
The pathology of multiple sclerosis is located in the central nervous system, therefore cerebrospinal fluid (CSF) is an attractive biofluid for biomarker research for proteins related to the early stages of this disease. In this study, the CSF proteome of patients with a clinically isolated syndrome of demyelination (CIS, a first attack of multiple sclerosis) is compared to the CSF proteome of control patients to identify differentially abundant proteins. CSF samples of 47 CIS patients and 45 control subjects are enzymatically digested and subsequently measured by LC-MS/MS (LTQ-Orbitrap). Following mass spectrometry differential abundances of the identified proteins between groups are investigated. A total of 3159 peptides are identified, relating to 485 proteins. One protein is significantly more abundant in CSF of CIS patients than in controls: Ig kappa chain C region. In contrast, 35 proteins are significantly lower in CIS patients than controls, most of them with functions in nervous system development and function, such as amyloid-like protein 1 (validated by ELISA in an independent sample set (p < 0.01)), contactin 1, contactin 2 and neuronal cell adhesion molecule. A remarkably lower abundance of neuro-axonal proteins is observed in patients with a first demyelinating event compared to controls.
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Affiliation(s)
- Marcel P Stoop
- Departments of Neurology, Erasmus MC, Rotterdam, the Netherlands
| | - Tessel F Runia
- Departments of Neurology, Erasmus MC, Rotterdam, the Netherlands
| | - Christoph Stingl
- Departments of Neurology, Erasmus MC, Rotterdam, the Netherlands
| | | | - Theo M Luider
- Departments of Neurology, Erasmus MC, Rotterdam, the Netherlands
| | - Rogier Q Hintzen
- Departments of Neurology, Erasmus MC, Rotterdam, the Netherlands.,Departments of Immunology, Erasmus MC, Rotterdam, the Netherlands
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7
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Han K, Müller UC, Hülsmann S. Amyloid-precursor Like Proteins APLP1 and APLP2 Are Dispensable for Normal Development of the Neonatal Respiratory Network. Front Mol Neurosci 2017; 10:189. [PMID: 28690498 PMCID: PMC5479907 DOI: 10.3389/fnmol.2017.00189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/29/2017] [Indexed: 11/13/2022] Open
Abstract
Recent studies using animal models indicated that the members of the amyloid precursor protein (APP) gene family are important for the formation, maintenance, and plasticity of synapses. Despite this, the specific role of the APP homologs APLP1 and APLP2 within the CNS and PNS is still poorly understood. In contrast to the subtle phenotypes of single mutants, double knockout mice (DKO) lacking APP/APLP2 or APLP1/APLP2 die within the first day after birth. Whereas APP/APLP2-DKO mice show severe deficits of neuromuscular morphology and transmission, the underlying cause of lethality of APLP1/APLP2-DKO mice remains unclear. Since expression of both proteins was confirmed by in situ hybridization, we aimed to test the role of APLP1/APLP2 in the formation and maintenance of synapses in the brainstem, and assessed a potential dysfunction of the most vital central neuronal network in APLP1/APLP2-DKO mice by analyzing the respiratory network of the medulla. We performed in vivo unrestrained whole body plethysmography in newborn APLP1/APLP2-DKO mice at postnatal day zero. Additionally, we directly tested the activity of the respiratory network in an acute slice preparation that includes the pre-Bötzinger complex. In both sets of experiments, no significant differences were detected regarding respiratory rate and cycle variability, strongly arguing against central respiratory problems as the primary cause of death of APLP1/APLP2-DKO mice. Thus, we conclude that APLP1 and APLP2 are dispensable for the development of the network and the generation of a normal breathing rhythm.
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Affiliation(s)
- Kang Han
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg UniversityHeidelberg, Germany
| | - Ulrike C Müller
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg UniversityHeidelberg, Germany
| | - Swen Hülsmann
- Klinik für Anästhesiologie, Universitätsmedizin GöttingenGöttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB)Göttingen, Germany
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8
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APLP1 Is a Synaptic Cell Adhesion Molecule, Supporting Maintenance of Dendritic Spines and Basal Synaptic Transmission. J Neurosci 2017; 37:5345-5365. [PMID: 28450540 DOI: 10.1523/jneurosci.1875-16.2017] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 02/22/2017] [Accepted: 03/24/2017] [Indexed: 12/19/2022] Open
Abstract
The amyloid precursor protein (APP), a key player in Alzheimer's disease, belongs to the family of synaptic adhesion molecules (SAMs) due to its impact on synapse formation and synaptic plasticity. These functions are mediated by both the secreted APP ectodomain that acts as a neurotrophic factor and full-length APP forming trans-cellular dimers. Two homologs of APP exist in mammals: the APP like proteins APLP1 and APLP2, exhibiting functions that partly overlap with those of APP. Here we tested whether APLP1 and APLP2 also show features of SAMs. We found that all three family members were upregulated during postnatal development coinciding with synaptogenesis. We observed presynaptic and postsynaptic localization of all APP family members and could show that heterologous expression of APLP1 or APLP2 in non-neuronal cells induces presynaptic differentiation in contacting axons of cocultured neurons, similar to APP and other SAMs. Moreover, APP/APLPs all bind to synaptic-signaling molecules, such as MINT/X11. Furthermore, we report that aged APLP1 knock-out mice show impaired basal transmission and a reduced mEPSC frequency, likely resulting from reduced spine density. This demonstrates an essential nonredundant function of APLP1 at the synapse. Compared to APP, APLP1 exhibits increased trans-cellular binding and elevated cell-surface levels due to reduced endocytosis. In conclusion, our results establish that APLPs show typical features of SAMs and indicate that increased surface expression, as observed for APLP1, is essential for proper synapse formation in vitro and synapse maintenance in vivoSIGNIFICANCE STATEMENT According to the amyloid-cascade hypothesis, Alzheimer's disease is caused by the accumulation of Aβ peptides derived from sequential cleavage of the amyloid precursor protein (APP) by β-site APP cleaving enzyme 1 (BACE1) and γ-secretase. Here we show that all mammalian APP family members (APP, APLP1, and APLP2) exhibit synaptogenic activity, involving trans-synaptic dimerization, similar to other synaptic cell adhesion molecules, such as Neuroligin/Neurexin. Importantly, our study revealed that the loss of APLP1, which is one of the major substrates of BACE1, causes reduced spine density in aged mice. Because some therapeutic interventions target APP processing (e.g., BACE inhibitors), those strategies may alter APP/APLP physiological function. This should be taken into account for the development of pharmaceutical treatments of Alzheimer's disease.
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9
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Magdalinou NK, Noyce AJ, Pinto R, Lindstrom E, Holmén-Larsson J, Holtta M, Blennow K, Morris HR, Skillbäck T, Warner TT, Lees AJ, Pike I, Ward M, Zetterberg H, Gobom J. Identification of candidate cerebrospinal fluid biomarkers in parkinsonism using quantitative proteomics. Parkinsonism Relat Disord 2017; 37:65-71. [PMID: 28214264 DOI: 10.1016/j.parkreldis.2017.01.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 01/02/2017] [Accepted: 01/27/2017] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Neurodegenerative parkinsonian syndromes have significant clinical and pathological overlap, making early diagnosis difficult. Cerebrospinal fluid (CSF) biomarkers may aid the differentiation of these disorders, but other than α-synuclein and neurofilament light chain protein, which have limited diagnostic power, specific protein biomarkers remain elusive. OBJECTIVES To study disease mechanisms and identify possible CSF diagnostic biomarkers through discovery proteomics, which discriminate parkinsonian syndromes from healthy controls. METHODS CSF was collected consecutively from 134 participants; Parkinson's disease (n = 26), atypical parkinsonian syndromes (n = 78, including progressive supranuclear palsy (n = 36), multiple system atrophy (n = 28), corticobasal syndrome (n = 14)), and elderly healthy controls (n = 30). Participants were divided into a discovery and a validation set for analysis. The samples were subjected to tryptic digestion, followed by liquid chromatography-mass spectrometry analysis for identification and relative quantification by isobaric labelling. Candidate protein biomarkers were identified based on the relative abundances of the identified tryptic peptides. Their predictive performance was evaluated by analysis of the validation set. RESULTS 79 tryptic peptides, derived from 26 proteins were found to differ significantly between atypical parkinsonism patients and controls. They included acute phase/inflammatory markers and neuronal/synaptic markers, which were respectively increased or decreased in atypical parkinsonism, while their levels in PD subjects were intermediate between controls and atypical parkinsonism. CONCLUSION Using an unbiased proteomic approach, proteins were identified that were able to differentiate atypical parkinsonian syndrome patients from healthy controls. Our study indicates that markers that may reflect neuronal function and/or plasticity, such as the amyloid precursor protein, and inflammatory markers may hold future promise as candidate biomarkers in parkinsonism.
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Affiliation(s)
- N K Magdalinou
- Reta Lila Weston Institute of Neurological Studies, UCL Institute of Neurology, Queen Square, London, UK.
| | - A J Noyce
- Reta Lila Weston Institute of Neurological Studies, UCL Institute of Neurology, Queen Square, London, UK
| | - R Pinto
- Institute of Chemistry University of Umeå, Umeå, Sweden
| | - E Lindstrom
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - J Holmén-Larsson
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - M Holtta
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - K Blennow
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - H R Morris
- Department of Clinical Neuroscience, UCL Institute of Neurology, Royal Free Hospital, London, UK
| | - T Skillbäck
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - T T Warner
- Reta Lila Weston Institute of Neurological Studies, UCL Institute of Neurology, Queen Square, London, UK
| | - A J Lees
- Reta Lila Weston Institute of Neurological Studies, UCL Institute of Neurology, Queen Square, London, UK
| | - I Pike
- Proteome Sciences Plc, London, UK
| | - M Ward
- Proteome Sciences Plc, London, UK
| | - H Zetterberg
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - J Gobom
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
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10
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Ludewig S, Korte M. Novel Insights into the Physiological Function of the APP (Gene) Family and Its Proteolytic Fragments in Synaptic Plasticity. Front Mol Neurosci 2017; 9:161. [PMID: 28163673 PMCID: PMC5247455 DOI: 10.3389/fnmol.2016.00161] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/14/2016] [Indexed: 12/31/2022] Open
Abstract
The amyloid precursor protein (APP) is well known to be involved in the pathophysiology of Alzheimer's disease (AD) via its cleavage product amyloid ß (Aß). However, the physiological role of APP, its various proteolytic products and the amyloid precursor-like proteins 1 and 2 (APLP1/2) are still not fully clarified. Interestingly, it has been shown that learning and memory processes represented by functional and structural changes at synapses are altered in different APP and APLP1/2 mouse mutants. In addition, APP and its fragments are implicated in regulating synaptic strength further reinforcing their modulatory role at the synapse. While APLP2 and APP are functionally redundant, the exclusively CNS expressed APLP1, might have individual roles within the synaptic network. The proteolytic product of non-amyloidogenic APP processing, APPsα, emerged as a neurotrophic peptide that facilitates long-term potentiation (LTP) and restores impairments occurring with age. Interestingly, the newly discovered η-secretase cleavage product, An-α acts in the opposite direction, namely decreasing LTP. In this review we summarize recent findings with emphasis on the physiological role of the APP gene family and its proteolytic products on synaptic function and plasticity, especially during processes of hippocampal LTP. Therefore, we focus on literature that provide electrophysiological data by using different mutant mouse strains either lacking full-length or parts of the APP proteins or that utilized secretase inhibitors as well as secreted APP fragments.
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Affiliation(s)
- Susann Ludewig
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig Braunschweig, Germany
| | - Martin Korte
- Division of Cellular Neurobiology, Zoological Institute, TU BraunschweigBraunschweig, Germany; Helmholtz Centre for Infection Research, AG NINDBraunschweig, Germany
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11
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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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12
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Begcevic I, Brinc D, Drabovich AP, Batruch I, Diamandis EP. Identification of brain-enriched proteins in the cerebrospinal fluid proteome by LC-MS/MS profiling and mining of the Human Protein Atlas. Clin Proteomics 2016; 13:11. [PMID: 27186164 PMCID: PMC4868024 DOI: 10.1186/s12014-016-9111-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 04/19/2016] [Indexed: 12/21/2022] Open
Abstract
Background Cerebrospinal fluid (CSF) is a proximal fluid which communicates closely with brain tissue, contains numerous brain-derived proteins and thus represents a promising fluid for discovery of biomarkers of central nervous system (CNS) diseases. The main purpose of this study was to generate an extensive CSF proteome and define brain-related proteins identified in CSF, suitable for development of diagnostic assays. Methods Six non-pathological CSF samples from three female and three male individuals were selected for CSF analysis. Samples were first subjected to strong cation exchange chromatography, followed by LC-MS/MS analysis. Secreted and membrane-bound proteins enriched in the brain tissues were retrieved from the Human Protein Atlas. Results In total, 2615 proteins were identified in the CSF. The number of proteins identified per individual sample ranged from 1109 to 1421, with inter-individual variability between six samples of 21 %. Based on the Human Protein Atlas, 78 brain-specific proteins found in CSF samples were proposed as a signature of brain-enriched proteins in CSF. Conclusion A combination of Human Protein Atlas database and experimental search of proteins in specific body fluid can be applied as an initial step in search for disease biomarkers specific for a particular tissue. This signature may be of significant interest for development of novel diagnostics of CNS diseases and identification of drug targets. Electronic supplementary material The online version of this article (doi:10.1186/s12014-016-9111-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ilijana Begcevic
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON Canada ; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON Canada
| | - Davor Brinc
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON Canada ; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON Canada ; Department of Clinical Biochemistry, University Health Network, Toronto, ON Canada
| | - Andrei P Drabovich
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON Canada ; Department of Clinical Biochemistry, University Health Network, Toronto, ON Canada
| | - Ihor Batruch
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON Canada
| | - Eleftherios P Diamandis
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON Canada ; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON Canada ; Department of Clinical Biochemistry, University Health Network, Toronto, ON Canada
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13
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The Association of Amyloid-β Protein Precursor With α- and β-Secretases in Mouse Cerebral Cortex Synapses Is Altered in Early Alzheimer’s Disease. Mol Neurobiol 2015; 53:5710-21. [DOI: 10.1007/s12035-015-9491-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 10/14/2015] [Indexed: 10/22/2022]
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14
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Vnencak M, Paul MH, Hick M, Schwarzacher SW, Del Turco D, Müller UC, Deller T, Jedlicka P. Deletion of the amyloid precursor-like protein 1 (APLP1) enhances excitatory synaptic transmission, reduces network inhibition but does not impair synaptic plasticity in the mouse dentate gyrus. J Comp Neurol 2015; 523:1717-29. [PMID: 25728909 DOI: 10.1002/cne.23766] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/21/2015] [Accepted: 02/23/2015] [Indexed: 01/02/2023]
Abstract
Amyloid precursor-like protein 1 (APLP1) is a transmembrane synaptic protein belonging to the amyloid precursor protein (APP) gene family. Although the role of this gene family-in particular of APP-has been intensely studied in the context of Alzheimer's disease, the physiological roles of its family members remain poorly understood. In particular, the function of APLP1, which is predominantly expressed in the nervous system, has remained enigmatic. Since APP has been implicated in synaptic plasticity, we wondered whether APLP1 could play a similar role. First, using in situ hybridization and laser microdissection combined with reverse transcription-quantitative polymerase chain reaction (PCR) we observed that Aplp1 mRNA is highly expressed in dentate granule cells. Having this examined, we studied synaptic plasticity at the perforant path-granule cell synapses in the dentate gyrus of APLP1-deficient mice in vivo. Analysis of field excitatory postsynaptic potentials evoked by stimulation of perforant path fibers revealed increased excitatory transmission in APLP1-deficient mice. Moreover, we observed decreased paired-pulse inhibition of population spikes indicating a decrease in network inhibition upon deletion of APLP1. In contrast, short-term presynaptic plasticity (STP) as well as long-term synaptic plasticity (LTP) was unchanged in the absence of APLP1. Based on these results we conclude that APLP1 deficiency on its own does not lead to defects in synaptic plasticity, but affects synaptic transmission and network inhibition in the dentate gyrus.
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Affiliation(s)
- Matej Vnencak
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University, Frankfurt am Main, Germany
| | - Mandy H Paul
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University, Frankfurt am Main, Germany
| | - Meike Hick
- Department of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Stephan W Schwarzacher
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University, Frankfurt am Main, Germany
| | - Domenico Del Turco
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University, Frankfurt am Main, Germany
| | - Ulrike C Müller
- Department of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University, Frankfurt am Main, Germany
| | - Peter Jedlicka
- Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe-University, Frankfurt am Main, Germany
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15
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Shi M, Movius J, Dator R, Aro P, Zhao Y, Pan C, Lin X, Bammler TK, Stewart T, Zabetian CP, Peskind ER, Hu SC, Quinn JF, Galasko DR, Zhang J. Cerebrospinal fluid peptides as potential Parkinson disease biomarkers: a staged pipeline for discovery and validation. Mol Cell Proteomics 2015; 14:544-55. [PMID: 25556233 DOI: 10.1074/mcp.m114.040576] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Finding robust biomarkers for Parkinson disease (PD) is currently hampered by inherent technical limitations associated with imaging or antibody-based protein assays. To circumvent the challenges, we adapted a staged pipeline, starting from our previous proteomic profiling followed by high-throughput targeted mass spectrometry (MS), to identify peptides in human cerebrospinal fluid (CSF) for PD diagnosis and disease severity correlation. In this multicenter study consisting of training and validation sets, a total of 178 subjects were randomly selected from a retrospective cohort, matching age and sex between PD patients, healthy controls, and neurological controls with Alzheimer disease (AD). From ∼14,000 unique peptides displaying differences between PD and healthy control in proteomic investigations, 126 peptides were selected based on relevance and observability in CSF using bioinformatic analysis and MS screening, and then quantified by highly accurate and sensitive selected reaction monitoring (SRM) in the CSF of 30 PD patients versus 30 healthy controls (training set), followed by diagnostic (receiver operating characteristics) and disease severity correlation analyses. The most promising candidates were further tested in an independent cohort of 40 PD patients, 38 AD patients, and 40 healthy controls (validation set). A panel of five peptides (derived from SPP1, LRP1, CSF1R, EPHA4, and TIMP1) was identified to provide an area under curve (AUC) of 0.873 (sensitivity = 76.7%, specificity = 80.0%) for PD versus healthy controls in the training set. The performance was essentially confirmed in the validation set (AUC = 0.853, sensitivity = 82.5%, specificity = 82.5%). Additionally, this panel could also differentiate the PD and AD groups (AUC = 0.990, sensitivity = 95.0%, specificity = 97.4%). Furthermore, a combination of two peptides belonging to proteins TIMP1 and APLP1 significantly correlated with disease severity as determined by the Unified Parkinson's Disease Rating Scale motor scores in both the training (r = 0.381, p = 0.038)j and the validation (r = 0.339, p = 0.032) sets. The novel panel of CSF peptides, if validated in independent cohorts, could be used to assist in clinical diagnosis of PD and has the potential to help monitoring or predicting disease progression.
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Affiliation(s)
- Min Shi
- From the ‡Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98104
| | - James Movius
- From the ‡Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98104
| | - Romel Dator
- From the ‡Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98104
| | - Patrick Aro
- From the ‡Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98104
| | - Yanchun Zhao
- From the ‡Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98104
| | - Catherine Pan
- From the ‡Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98104
| | - Xiangmin Lin
- From the ‡Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98104; §School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Theo K Bammler
- ¶Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington 98195
| | - Tessandra Stewart
- From the ‡Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98104
| | - Cyrus P Zabetian
- ‖Geriatric and Parkinson's Disease Research, Education, and Clinical Centers, Veterans Affairs Puget Sound Health Care System, Seattle, Washington 98108; **Department of Neurology, University of Washington School of Medicine, Seattle, Washington 98195
| | - Elaine R Peskind
- ‡‡Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington 98195; §§Mental Illness Research, Education, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington 98108
| | - Shu-Ching Hu
- ‖Geriatric and Parkinson's Disease Research, Education, and Clinical Centers, Veterans Affairs Puget Sound Health Care System, Seattle, Washington 98108; **Department of Neurology, University of Washington School of Medicine, Seattle, Washington 98195
| | - Joseph F Quinn
- ¶¶Department of Neurology, Oregon Health and Science University, Portland, Oregon 97239
| | - Douglas R Galasko
- ‖‖Department of Neurosciences, University of California at San Diego, La Jolla, California 92093
| | - Jing Zhang
- From the ‡Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98104;
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16
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Stahl R, Schilling S, Soba P, Rupp C, Hartmann T, Wagner K, Merdes G, Eggert S, Kins S. Shedding of APP limits its synaptogenic activity and cell adhesion properties. Front Cell Neurosci 2014; 8:410. [PMID: 25520622 PMCID: PMC4253958 DOI: 10.3389/fncel.2014.00410] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 11/11/2014] [Indexed: 01/05/2023] Open
Abstract
The amyloid precursor protein (APP) plays a central role in Alzheimer's disease (AD) and has essential synapse promoting functions. Synaptogenic activity as well as cell adhesion properties of APP presumably depend on trans-cellular dimerization via its extracellular domain. Since neuronal APP is extensively processed by secretases, it raises the question if APP shedding affects its cell adhesion and synaptogenic properties. We show that inhibition of APP shedding using cleavage deficient forms of APP or a dominant negative α-secretase strongly enhanced its cell adhesion and synaptogenic activity suggesting that synapse promoting function of APP is tightly regulated by α-secretase mediated processing, similar to other trans-cellular synaptic adhesion molecules.
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Affiliation(s)
- Ronny Stahl
- Center of Molecular Biology ZMBH, University of Heidelberg Heidelberg, Germany ; Department of Physiological Genomics, Institute of Physiology, Ludwig-Maximilians University Munich Munich, Germany
| | - Sandra Schilling
- Department of Human Biology and Human Genetics, Technical University of Kaiserslautern Kaiserslautern, Germany
| | - Peter Soba
- Center of Molecular Biology ZMBH, University of Heidelberg Heidelberg, Germany ; Center for Molecular Neurobiology (ZMNH), University of Hamburg Hamburg, Germany
| | - Carsten Rupp
- Department of Human Biology and Human Genetics, Technical University of Kaiserslautern Kaiserslautern, Germany
| | - Tobias Hartmann
- Deutsches Institut für DemenzPrävention, Experimental Neurology, Saarland University Homburg/Saar, Germany
| | - Katja Wagner
- Center of Molecular Biology ZMBH, University of Heidelberg Heidelberg, Germany ; Department of Human Biology and Human Genetics, Technical University of Kaiserslautern Kaiserslautern, Germany
| | - Gunter Merdes
- Center of Molecular Biology ZMBH, University of Heidelberg Heidelberg, Germany ; Department of Biosystems Science and Engineering, ETH Zürich Basel, Switzerland
| | - Simone Eggert
- Department of Human Biology and Human Genetics, Technical University of Kaiserslautern Kaiserslautern, Germany
| | - Stefan Kins
- Center of Molecular Biology ZMBH, University of Heidelberg Heidelberg, Germany ; Department of Human Biology and Human Genetics, Technical University of Kaiserslautern Kaiserslautern, Germany ; Deutsches Institut für DemenzPrävention, Experimental Neurology, Saarland University Homburg/Saar, Germany
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17
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Mayer MC, Kaden D, Schauenburg L, Hancock MA, Voigt P, Roeser D, Barucker C, Than ME, Schaefer M, Multhaup G. Novel zinc-binding site in the E2 domain regulates amyloid precursor-like protein 1 (APLP1) oligomerization. J Biol Chem 2014; 289:19019-30. [PMID: 24855651 DOI: 10.1074/jbc.m114.570382] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The amyloid precursor protein (APP) and the APP-like proteins 1 and 2 (APLP1 and APLP2) are a family of multidomain transmembrane proteins possessing homo- and heterotypic contact sites in their ectodomains. We previously reported that divalent metal ions dictate the conformation of the extracellular APP E2 domain (Dahms, S. O., Könnig, I., Roeser, D., Gührs, K.-H., Mayer, M. C., Kaden, D., Multhaup, G., and Than, M. E. (2012) J. Mol. Biol. 416, 438-452), but unresolved is the nature and functional importance of metal ion binding to APLP1 and APLP2. We found here that zinc ions bound to APP and APLP1 E2 domains and mediated their oligomerization, whereas the APLP2 E2 domain interacted more weakly with zinc possessing a less surface-exposed zinc-binding site, and stayed monomeric. Copper ions bound to E2 domains of all three proteins. Fluorescence resonance energy transfer (FRET) analyses examined the effect of metal ion binding to APP and APLPs in the cellular context in real time. Zinc ions specifically induced APP and APLP1 oligomerization and forced APLP1 into multimeric clusters at the plasma membrane consistent with zinc concentrations in the blood and brain. The observed effects were mediated by a novel zinc-binding site within the APLP1 E2 domain as APLP1 deletion mutants revealed. Based upon its cellular localization and its dominant response to zinc ions, APLP1 is mainly affected by extracellular zinc among the APP family proteins. We conclude that zinc binding and APP/APLP oligomerization are intimately linked, and we propose that this represents a novel mechanism for regulating APP/APLP protein function at the molecular level.
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Affiliation(s)
- Magnus C Mayer
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Daniela Kaden
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Linda Schauenburg
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Mark A Hancock
- the Department of Pharmacology and Therapeutics, McGill University Montreal, Montreal, Quebec H3G 1Y6, Canada
| | - Philipp Voigt
- the Molekulare Pharmakologie und Zellbiologie, Thielallee 67-73, Neurowissenschaftliches Forschungszentrum, Charité-Universitätsmedizin Berlin, 14195 Berlin, Germany
| | - Dirk Roeser
- the Leibniz Institute for Age Research, Protein Crystallography Group, Fritz Lipmann Institute, Beutenbergstrasse 11, 07745 Jena, Germany, and
| | - Christian Barucker
- the Department of Pharmacology and Therapeutics, McGill University Montreal, Montreal, Quebec H3G 1Y6, Canada
| | - Manuel E Than
- the Leibniz Institute for Age Research, Protein Crystallography Group, Fritz Lipmann Institute, Beutenbergstrasse 11, 07745 Jena, Germany, and
| | - Michael Schaefer
- the Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Medizinische Fakultät der Universität Leipzig, Härtelstrasse 16-18, 04107 Leipzig, Germany
| | - Gerhard Multhaup
- From the Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany, the Department of Pharmacology and Therapeutics, McGill University Montreal, Montreal, Quebec H3G 1Y6, Canada,
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18
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Baumkötter F, Wagner K, Eggert S, Wild K, Kins S. Structural aspects and physiological consequences of APP/APLP trans-dimerization. Exp Brain Res 2012; 217:389-95. [PMID: 21952790 PMCID: PMC3308009 DOI: 10.1007/s00221-011-2878-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 09/13/2011] [Indexed: 12/02/2022]
Abstract
The amyloid precursor protein (APP) is one of the key proteins in Alzheimer's disease (AD), as it is the precursor of amyloid β (Aβ) peptides accumulating in amyloid plaques. The processing of APP and the pathogenic features of especially Aβ oligomers have been analyzed in detail. Remarkably, there is accumulating evidence from cell biological and structural studies suggesting that APP and its mammalian homologs, the amyloid precursor-like proteins (APLP1 and APLP2), participate under physiological conditions via trans-cellular dimerization in synaptogenesis. This offers the possibility that loss of synapses in AD might be partially explained by dysfunction of APP/APLPs cell adhesion properties. In this review, structural characteristics of APP trans-cellular interaction will be placed critically in context with its putative physiological functions focusing on cell adhesion and synaptogenesis.
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Affiliation(s)
- Frederik Baumkötter
- Department of Human Biology and Human Genetics, Technical University of Kaiserslautern, Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany
| | - Katja Wagner
- Department of Human Biology and Human Genetics, Technical University of Kaiserslautern, Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany
| | - Simone Eggert
- Department of Human Biology and Human Genetics, Technical University of Kaiserslautern, Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany
| | - Klemens Wild
- Heidelberg University Biochemistry Center, University of Heidelberg, 69120 Heidelberg, Germany
| | - Stefan Kins
- Department of Human Biology and Human Genetics, Technical University of Kaiserslautern, Erwin-Schrödinger-Straße 13, 67663 Kaiserslautern, Germany
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19
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Peters HL, Tuli A, Sharma M, Naslavsky N, Caplan S, MacDonald RG, Solheim JC. Regulation of major histocompatibility complex class I molecule expression on cancer cells by amyloid precursor-like protein 2. Immunol Res 2012; 51:39-44. [PMID: 21826533 DOI: 10.1007/s12026-011-8238-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The three members of the amyloid precursor protein family in mammals [amyloid precursor protein, amyloid precursor-like protein 1, and amyloid precursor-like protein 2 (APLP2)] have been implicated in a large array of intracellular processes, which include development, transcription, apoptosis, metabolism, and the cell cycle. A series of studies by our laboratories has demonstrated that APLP2 is highly expressed by many cancer cell lines (with the highest expression in pancreatic cancer cell lines) and that it facilitates major histocompatibility complex (MHC) class I molecule endocytosis. This review focuses on this recently revealed function of APLP2 relevant to tumor immunology: that it acts as a novel regulator of MHC class I molecule surface expression.
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Affiliation(s)
- Haley L Peters
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
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20
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Suh J, Lyckman A, Wang L, Eckman EA, Guénette SY. FE65 proteins regulate NMDA receptor activation-induced amyloid precursor protein processing. J Neurochem 2011; 119:377-88. [PMID: 21824144 PMCID: PMC3188680 DOI: 10.1111/j.1471-4159.2011.07419.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Amyloid precursor protein (APP) family members and their proteolytic products are implicated in normal nervous system function and Alzheimer's disease pathogenesis. APP processing and Aβ secretion are regulated by neuronal activity. Various data suggest that NMDA receptor (NMDAR) activity plays a role in both non-amyloidogenic and amyloidogenic APP processing depending on whether synaptic or extrasynaptic NMDARs are activated, respectively. The APP-interacting FE65 proteins modulate APP trafficking and processing in cell lines, but little is known about their contribution to APP trafficking and processing in neurons, either in vivo or in vitro. In this study, we examined the contribution of the FE65 protein family to APP trafficking and processing in WT and FE65/FE65L1 double knockout neurons under basal conditions and following NMDAR activation. We report that FE65 proteins facilitate neuronal Aβ secretion without affecting APP fast axonal transport to pre-synaptic terminals. In addition, FE65 proteins facilitate an NMDAR-dependent non-amyloidogenic APP processing pathway. Generation of high-molecular weight (HMW) species bearing an APP C-terminal epitope was also observed following NMDAR activation. These HMW species require proteasomal and calpain activities for their accumulation. Recovery of APP polypeptide fragments from electroeluted HMW species having molecular weights consistent with calpain I cleavage of APP suggests that HMW species are complexes formed from APP metabolic products. Our results indicate that the FE65 proteins contribute to physiological APP processing and accumulation of APP metabolic products resulting from NMDAR activation.
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Affiliation(s)
- Jaehong Suh
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
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21
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Frigerio CS, Fadeeva JV, Minogue AM, Citron M, Leuven FV, Stufenbiel M, Paganetti P, Selkoe DJ, Walsh DM. beta-Secretase cleavage is not required for generation of the intracellular C-terminal domain of the amyloid precursor family of proteins. FEBS J 2010; 277:1503-18. [PMID: 20163459 PMCID: PMC2847843 DOI: 10.1111/j.1742-4658.2010.07579.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The amyloid precursor family of proteins are of considerable interest, both because of their role in Alzheimer's disease pathogenesis and because of their normal physiological functions. In mammals, the amyloid precursor protein (APP) has two homologs, amyloid precursor-like protein (APLP) 1 and APLP2. All three proteins undergo ectodomain shedding and regulated intramembrane proteolysis, and important functions have been attributed to the full-length proteins, shed ectodomains, C-terminal fragments and intracellular domains (ICDs). One of the proteases that is known to cleave APP and that is essential for generation of the amyloid beta-protein is the beta-site APP-cleaving enzyme 1 (BACE1). Here, we investigated the effects of genetic manipulation of BACE1 on the processing of the APP family of proteins. BACE1 expression regulated the levels and species of full-length APLP1, APP and APLP2, of their shed ectodomains, and of their membrane-bound C-terminal fragments. In particular, APP processing appears to be tightly regulated, with changes in beta-cleaved APPs (APPsbeta) being compensated for by changes in alpha-cleaved APPs (APPsalpha). In contrast, the total levels of soluble cleaved APLP1 and APLP2 species were less tightly regulated, and fluctuated with BACE1 expression. Importantly, the production of ICDs for all three proteins was not decreased by loss of BACE1 activity. These results indicate that BACE1 is involved in regulating ectodomain shedding, maturation and trafficking of the APP family of proteins. Consequently, whereas inhibition of BACE1 is unlikely to adversely affect potential ICD-mediated signaling, it may alter other important facets of amyloid precursor-like protein/APP biology.
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Affiliation(s)
- Carlo Sala Frigerio
- Laboratory for Neurodegenerative Research, The Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Republic of Ireland
| | - Julia V. Fadeeva
- Department of Neurology, Harvard Medical School and Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA 02115
| | - Aedín M. Minogue
- Laboratory for Neurodegenerative Research, The Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Republic of Ireland
| | - Martin Citron
- Amgen Inc., Thousand Oaks, CA 91320-1799, Current affiliation: Eli Lilly and Company, Indianapolis, IN 46285
| | - Fred Van Leuven
- Department of Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Matthias Stufenbiel
- Nervous System Research, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Paolo Paganetti
- Nervous System Research, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Dennis J. Selkoe
- Department of Neurology, Harvard Medical School and Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, MA 02115
| | - Dominic M. Walsh
- Laboratory for Neurodegenerative Research, The Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Republic of Ireland
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22
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Didych DA, Akopov SB, Snezhkov EV, Skaptsova NV, Nikolaev LG, Sverdlov ED. Identification and mapping of ten new potential insulators in the FXYD5-COX7A1 region of human chromosome 19q13.12. BIOCHEMISTRY (MOSCOW) 2009; 74:728-33. [PMID: 19747092 DOI: 10.1134/s0006297909070049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A positive-negative selection system revealed 10 potential insulators able to block enhancer interaction with promoter in the 10(6) bp human chromosome 19 region between genes FXYD5 and COX7A1. Relative positions of insulators and genes are in accord with the hypothesis that insulators subdivide genomic DNA into independently regulated loop domains.
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Affiliation(s)
- D A Didych
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
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23
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Hoe HS, Fu Z, Makarova A, Lee JY, Lu C, Feng L, Pajoohesh-Ganji A, Matsuoka Y, Hyman BT, Ehlers MD, Vicini S, Pak DTS, Rebeck GW. The effects of amyloid precursor protein on postsynaptic composition and activity. J Biol Chem 2009; 284:8495-506. [PMID: 19164281 PMCID: PMC2659208 DOI: 10.1074/jbc.m900141200] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Indexed: 11/06/2022] Open
Abstract
The amyloid precursor protein (APP) is cleaved to produce the Alzheimer disease-associated peptide Abeta, but the normal functions of uncleaved APP in the brain are unknown. We found that APP was present in the postsynaptic density of central excitatory synapses and coimmunoprecipitated with N-methyl-d-aspartate receptors (NMDARs). The presence of APP in the postsynaptic density was supported by the observation that NMDARs regulated trafficking and processing of APP; overexpression of the NR1 subunit increased surface levels of APP, whereas activation of NMDARs decreased surface APP and promoted production of Abeta. We transfected APP or APP RNA interference into primary neurons and used electrophysiological techniques to explore the effects of APP on postsynaptic function. Reduction of APP decreased (and overexpression of APP increased) NMDAR whole cell current density and peak amplitude of spontaneous miniature excitatory postsynaptic currents. The increase in NMDAR current by APP was due to specific recruitment of additional NR2B-containing receptors. Consistent with these findings, immunohistochemical experiments demonstrated that APP increased the surface levels and decreased internalization of NR2B subunits. These results demonstrate a novel physiological role of postsynaptic APP in enhancing NMDAR function.
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Affiliation(s)
- Hyang-Sook Hoe
- Departments of Neuroscience, Physiology and Biophysics, Pharmacology, and Neurology, Georgetown University Medical Center, Washington, D. C. 20057-1464, USA
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24
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Schrenk-Siemens K, Perez-Alcala S, Richter J, Lacroix E, Rahuel J, Korte M, Müller U, Barde YA, Bibel M. Embryonic stem cell-derived neurons as a cellular system to study gene function: lack of amyloid precursor proteins APP and APLP2 leads to defective synaptic transmission. Stem Cells 2008; 26:2153-63. [PMID: 18535156 DOI: 10.1634/stemcells.2008-0010] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The in vitro generation of uniform populations of neurons from mouse embryonic stem cells (ESCs) provides a novel opportunity to study gene function in neurons. This is of particular interest when mutations lead to lethal in vivo phenotypes. Although the amyloid precursor protein (APP) and its proteolysis are regarded as key elements of the pathology of Alzheimer's disease, the physiological function of APP is not well understood and mice lacking App and the related gene Aplp2 die early postnatally without any obvious histopathological abnormalities. Here we show that glutamatergic neurons differentiated from ESCs lacking both genes reveal a decreased expression of the vesicular glutamate transporter 2 (VGLUT2) both at the mRNA and protein level, as well as a reduced uptake and/or release of glutamate. Blocking gamma-secretase cleavage of APP in wild-type neurons resulted in a similar decrease of VGLUT2 expression, whereas VGLUT2 levels could be restored in App-/-Aplp2-/- neurons by a construct encompassing the C-terminal intracellular domain of APP. Electrophysiological recordings of hippocampal organotypic slice cultures prepared from corresponding mutant mice corroborated these observations. Gene expression profiling and pathway analysis of the differentiated App-/-Aplp2-/- neurons identified dysregulation of additional genes involved in synaptic transmission pathways. Our results indicate a significant functional role of APP and amyloid precursor-like protein 2 (APLP2) in the development of synaptic function by the regulation of glutamatergic neurotransmission. Differentiation of ESCs into homogeneous populations thus represents a new opportunity to explore gene function and to dissect signaling pathways in neurons. Disclosure of potential conflicts of interest is found at the end of this article.
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Affiliation(s)
- Katrin Schrenk-Siemens
- Neurodegeneration Department, Neuroscience Research, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
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25
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Regulated proteolysis of APP and ApoE receptors. Mol Neurobiol 2008; 37:64-72. [PMID: 18415033 DOI: 10.1007/s12035-008-8017-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Accepted: 03/24/2008] [Indexed: 10/22/2022]
Abstract
The beta-amyloid precursor protein (APP) shares intracellular and extracellular-binding partners with the family of receptors for apolipoprotein E (apoE). Binding of APP and apoE receptors to specific extracellular matrix proteins (F-spondin and Reelin) promotes their presence on the cell surface and influences whether they will interact with specific cytoplasmic adaptor proteins. Cleavage of APP and apoE receptors at the cell surface occurs by alpha-secretase activities; thus, the processing of these proteins can be regulated by their trafficking either to or from the cell surface. Their cleavages can also be regulated by tissue inhibitor of metalloproteinase-3 (TIMP-3), a metalloprotease inhibitor in the extracellular matrix. ApoE receptors have functions in neuronal migration during development and in proper synaptic function in the adult. Thus, the functions of apoE receptors and by analogy of APP will be modified by the various extracellular and intracellular interactions reviewed in this paper.
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26
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Guilarte TR, Burton NC, Verina T, Prabhu VV, Becker KG, Syversen T, Schneider JS. Increased APLP1 expression and neurodegeneration in the frontal cortex of manganese-exposed non-human primates. J Neurochem 2008; 105:1948-59. [PMID: 18284614 DOI: 10.1111/j.1471-4159.2008.05295.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Chronic manganese (Mn) exposure produces a neurological syndrome with psychiatric, cognitive, and parkinsonian features. Gene expression profiling in the frontal cortex of Cynomologous macaques receiving 3.3-5.0 mg Mn/kg weekly for 10 months showed that 61 genes were increased and four genes were decreased relative to controls from a total of 6766 genes. Gene changes were associated with cell cycle regulation, DNA repair, apoptosis, ubiquitin-proteasome system, protein folding, cholesterol homeostasis, axonal/vesicular transport, and inflammation. Amyloid-beta (Abeta) precursor-like protein 1, a member of the amyloid precursor protein family, was the most highly up-regulated gene. Immunohistochemistry confirmed increased amyloid precursor-like protein 1 protein expression and revealed the presence of diffuse Abeta plaques in Mn-exposed frontal cortex. Cortical neurons and white matter fibers from Mn-exposed animals accumulated silver grains indicative of on-going degeneration. Cortical neurons also exhibited nuclear hypertrophy, intracytoplasmic vacuoles, and apoptosis stigmata. p53 immunolabeling was increased in the cytoplasm of neurons and in the nucleus and processes of glial cells in Mn-exposed tissue. In summary, chronic Mn exposure produces a cellular stress response leading to neurodegenerative changes and diffuse Abeta plaques in the frontal cortex. These changes may explain the subtle cognitive deficits previously demonstrated in these same animals.
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Affiliation(s)
- Tomás R Guilarte
- Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205, USA.
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27
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Tang X, Milyavsky M, Goldfinger N, Rotter V. Amyloid-beta precursor-like protein APLP1 is a novel p53 transcriptional target gene that augments neuroblastoma cell death upon genotoxic stress. Oncogene 2007; 26:7302-12. [PMID: 17533371 DOI: 10.1038/sj.onc.1210542] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The tumor suppressor p53 is a key modulator of the cellular stress response, inducing cell-cycle arrest, apoptosis, senescence and cell differentiation. To evaluate further the molecular mechanism underlying p53 function, the transcriptional profiles of proliferating and senescent WI-38 cells, both wild-type p53 expressers and counterparts with an inactivated p53, were compared by DNA microarray analysis. In particular, the amyloid-beta precursor-like protein 1 (APLP1) is induced in senescent cells in a p53-dependent manner. APLP1 was confirmed to be a novel transcriptional target of p53 by in vivo and in vitro characterization of a p53 responsive element found in the first intron of the APLP1 gene locus. APLP1 knockdown experiments demonstrate that APLP1 is required for the proliferation of fibroblastic and epithelial cells. Moreover, depletion of APLP1 expression diminishes stress-induced apoptosis of neural cells, whereas ectopic APLP1 expression augments apoptosis. Based on these data, a mechanism is proposed whereby p53-dependent induction of APLP1 is involved in neural cell death, and which may exacerbate neuronal cell loss in some acute or chronic neurodegenerative disorders.
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Affiliation(s)
- X Tang
- Department of Molecular Cell Biology, The Weizmann Institute of Science, Rehovot, Israel
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28
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Weber B, Schaper C, Scholz J, Bein B, Rodde C, H Tonner P. Interaction of the amyloid precursor like protein 1 with the alpha2A-adrenergic receptor increases agonist-mediated inhibition of adenylate cyclase. Cell Signal 2006; 18:1748-57. [PMID: 16531006 DOI: 10.1016/j.cellsig.2006.01.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Revised: 01/24/2006] [Accepted: 01/24/2006] [Indexed: 10/24/2022]
Abstract
Alpha2-adrenergic receptor agonists exert potent analgesic and sedative/hypnotic effects. In addition, they have been shown to be neuroprotective, but the mechanisms of these actions are still poorly defined. To isolate proteins that may control alpha2-adrenergic receptor function or trafficking, we performed a two-hybrid screen using the carboxy-terminal fourth intracellular tail of the alpha2A-adrenergic receptor as bait. This screen identified the amyloid precursor like protein 1 (APLP1), a homologue of the beta-amyloid precursor protein involved in Alzheimer's disease, as alpha2A-adrenergic receptor-binding protein. GST affinity chromatography revealed that APLP1 specifically interacts with all three human alpha2-adrenergic receptor subtypes and deletion mutant analysis confined the APLP1 domain involved in binding to alpha2-adrenergic receptors to the 13 amino acid residues Ser599-Ala611. Coimmunoprecipitations of transiently transfected cells with epitope-tagged APLP1 and alpha2-adrenergic receptors confirmed the interaction. Agonist treatment tended to increase the amount of alpha2A-adrenergic receptor associated with APLP1 while coimmunoprecipitations were not affected by the state of receptor phosphorylation or cotransfection of arrestin-3. Confocal laser microscopy showed that APLP1 causes a considerable shift of the alpha2A-adrenergic receptor localization from plasma membrane to intracellular compartments. Furthermore, cotransfection of alpha2A-adrenergic receptor and APLP1 into HEK293 cells significantly increased norepinephrine mediated inhibition of adenylate cyclase activity. These results suggest a possible role of APLP1 in regulation of alpha2A-adrenergic receptor trafficking. Moreover, we speculate that this interaction may present one mechanism by which alpha2-adrenergic receptor agonists exert their neuroprotective effects.
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Affiliation(s)
- Bernd Weber
- Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Schwanenweg 21, 24105 Kiel, Germany.
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29
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Kins S, Lauther N, Szodorai A, Beyreuther K. Subcellular Trafficking of the Amyloid Precursor Protein Gene Family and Its Pathogenic Role in Alzheimer’s Disease. NEURODEGENER DIS 2006; 3:218-26. [PMID: 17047360 DOI: 10.1159/000095259] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Changes in the intracellular transport of amyloid precursor protein (APP) affect the extent to which APP is exposed to alpha- or beta-secretase in a common subcellular compartment and therefore directly influence the degree to which APP undergoes the amyloidogenic pathway leading to generation of beta-amyloid. As the presynaptic regions of neurons are thought to be the main source of beta-amyloid in the brain, attention has been focused on axonal APP trafficking. APP is transported along axons by a fast, kinesin-dependent anterograde transport mechanism. Despite the wealth of in vivo and in vitro data that have accumulated regarding the connection of APP to kinesin transport, it is not yet clear if APP is coupled to its specific motor protein via an intracellular interaction partner, such as the c-Jun N-terminal kinase-interacting protein, or by yet another unknown molecular mechanism. The cargo proteins that form a functional complex with APP are also unknown. Due to the long lifespan, and vast extent, of neurons, in particular axons, neurons are highly sensitive to changes in subcellular transport. Recent in vitro and in vivo studies have shown that variations in APP or tau affect mitochondrial and synaptic vesicle transport. Further, it was shown that this axonal dysfunction might lead to impaired synaptic plasticity, which is crucial for neuronal viability and function. Thus, changes in APP and tau expression may cause perturbed axonal transport and changes in APP processing, contributing to cognitive decline and neurodegeneration in Alzheimer's disease.
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Affiliation(s)
- Stefan Kins
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany.
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30
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Abstract
Glutamatergic synapses in the central nervous system are characterized by an electron-dense web underneath the postsynaptic membrane; this web is called the postsynaptic density (PSD). PSDs are composed of a dense network of several hundred proteins, creating a macromolecular complex that serves a wide range of functions. Prominent PSD proteins such as members of the MaGuk or ProSAP/Shank family build up a dense scaffold that creates an interface between clustered membrane-bound receptors, cell adhesion molecules and the actin-based cytoskeleton. Moreover, kinases, phosphatases and several proteins of different signalling pathways are specifically localized within the spine/PSD compartment. Small GTPases and regulating proteins are also enriched in PSDs being the molecular basis for regulated structural changes of cytoskeletal components within the synapse in response to external or internal stimuli, e.g. synaptic activation. This synaptic rearrangement (structural plasticity) is a rapid process and is believed to underlie learning and memory formation. The characterization of synapse/PSD proteins is especially important in the light of recent data suggesting that several mental disorders have their molecular defect at the synapse/PSD level.
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Affiliation(s)
- T M Boeckers
- Department of Anatomy and Cell Biology, Ulm University, 89081 Ulm, Germany.
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31
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Xu Y, Kim HS, Joo Y, Choi Y, Chang KA, Park CH, Shin KY, Kim S, Cheon YH, Baik TK, Kim JH, Suh YH. Intracellular domains of amyloid precursor-like protein 2 interact with CP2 transcription factor in the nucleus and induce glycogen synthase kinase-3β expression. Cell Death Differ 2006; 14:79-91. [PMID: 16645641 DOI: 10.1038/sj.cdd.4401928] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Amyloid precursor protein (APP) is a member of a gene family that includes two APP-like proteins, APLP1 and 2. Recently, it has been reported that APLP1 and 2 undergo presenilin-dependent gamma-secretase cleavage, as does APP, resulting in the release of an approximately 6 kDa intracellular C-terminal domain (ICD), which can translocate into the nucleus. In this study, we demonstrate that the APLP2-ICDs interact with CP2/LSF/LBP1 (CP2) transcription factor in the nucleus and induce the expression of glycogen synthase kinase 3beta (GSK-3beta), which has broad-ranged substrates such as tau- and beta-catenin. The significance of this finding is substantiated by the in vivo evidence of the increase in the immunoreactivities for the nuclear C-terminal fragments of APLP2, and for GSK-3beta in the AD patients' brain. Taken together, these results suggest that APLP2-ICDs contribute to the AD pathogenesis, by inducing GSK-3beta expression through the interaction with CP2 transcription factor in the nucleus.
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Affiliation(s)
- Y Xu
- Department of Pharmacology, College of Medicine, National Creative Research Initiative Center for Alzheimer's Dementia and Neuroscience Research Institute, MRC, Seoul National University, Seoul, South Korea
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32
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Conboy L, Murphy KJ, Regan CM. Amyloid precursor protein expression in the rat hippocampal dentate gyrus modulates during memory consolidation. J Neurochem 2005; 95:1677-88. [PMID: 16236032 DOI: 10.1111/j.1471-4159.2005.03484.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Despite advances in our understanding of the basic biology of amyloid precursor protein (APP), the normal physiological function(s) of APP in learning and memory remains unclear. Here we show increased APP degradation in the hippocampus to be associated with the consolidation of a passive avoidance response. Neurone-specific APP695 expression became transiently reduced 2-4 h post-training through association with endosomal adaptin proteins and enhanced internalization. By contrast, internalization of glial-associated APP containing a Kunitz protease inhibitor-like domain (APP-KPI) was dependent on the low-density lipoprotein receptor-related protein (LRP). In addition, LRP expression and association with apolipoprotein E increased in the 2-4 h post-training period. The LRP antagonist receptor-associated protein prevented the APP-KPI internalization and LRP-apolipoprotein E association and this resulted in amnesia. Degradation of APP695 and APP-KPI did not appear to be related to alpha-secretase activity, as no learning-associated increase of secreted APP was observed in the CSF. Moreover, as internalization of APP isoforms was observed only in dentate gyrus, it probably relates to the learning-associated restructuring of the perforant path terminals. Memory-associated APP processing in both neuronal and glial compartments points to a role for glial unsheathing of synaptic connections, an event required for the synaptic restructuring that accompanies memory consolidation. These observations may have a direct relevance to understanding the pathophysiology of Alzheimer's disease as beta/gamma-secretase-derived beta-amyloid is formed following internalization of cell surface APP into the endosomal compartment.
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Affiliation(s)
- Lisa Conboy
- Applied Neurotherapeutics Research Group, Department of Pharmacology, Conway Institute, University College Dublin, Belfield, Dublin, Ireland
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33
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Soba P, Eggert S, Wagner K, Zentgraf H, Siehl K, Kreger S, Löwer A, Langer A, Merdes G, Paro R, Masters CL, Müller U, Kins S, Beyreuther K. Homo- and heterodimerization of APP family members promotes intercellular adhesion. EMBO J 2005; 24:3624-34. [PMID: 16193067 PMCID: PMC1276707 DOI: 10.1038/sj.emboj.7600824] [Citation(s) in RCA: 223] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Accepted: 09/01/2005] [Indexed: 02/07/2023] Open
Abstract
The amyloid precursor protein (APP) plays a central role in Alzheimer's disease, but its physiological function and that of its mammalian paralogs, the amyloid precursor-like proteins 1 and 2 (APLPs), is still poorly understood. APP has been proposed to form dimers, a process that could promote cell adhesion via trans-dimerization. We investigated the dimerization and cell adhesion properties of APP/APLPs and provide evidence that all three paralogs are capable of forming homo- and heterocomplexes. Moreover, we show that trans-interaction of APP family proteins promotes cell-cell adhesion in a homo- and heterotypic fashion and that endogenous APLP2 is required for cell-cell adhesion in mouse embryonic fibroblasts. We further demonstrate interaction of all the three APP family members in mouse brain, genetic interdependence, and molecular interaction of APP and APLPs in synaptically enriched membrane compartments. Together, our results provide evidence that homo- and heterocomplexes of APP/APLPs promote trans-cellular adhesion in vivo.
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Affiliation(s)
- Peter Soba
- ZMBH, University of Heidelberg, Heidelberg, Germany.
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34
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López-Sánchez N, Müller U, Frade JM. Lengthening of G2/mitosis in cortical precursors from mice lacking β-amyloid precursor protein. Neuroscience 2005; 130:51-60. [PMID: 15561424 DOI: 10.1016/j.neuroscience.2004.09.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2004] [Indexed: 12/31/2022]
Abstract
The beta-amyloid precursor protein (APP) is expressed within the nervous system, even at the earliest stages of embryonic development when cell growth and proliferation is particularly important. In order to study the function of APP at these early developmental stages, we have studied the development of the cerebral cortex in both wild type and App-/- mutant mice. Here, we demonstrate that APP mRNA is expressed in cortical precursor cells and that APP protein is concentrated within their apical domains during interphase. However, during mitosis, APP re-localizes to the peripheral space surrounding the metaphase plate. In APP-deficient cortical precursors, the duration of mitosis is increased and a higher proportion of cortical precursor cells contained nuclei in late G2. We conclude that during cortical development APP plays a role in controlling cell cycle progression, particularly affecting G2 and mitosis. These observations may have important implications for our understanding of how APP influences the progression of Alzheimer's disease, since degenerating cortical neurons have been shown to up-regulate cell cycle markers and re-enter the mitotic cycle before dying.
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Affiliation(s)
- N López-Sánchez
- Instituto Cajal, CSIC, Avda. Dr Arce, 37, E-28002 Madrid, Spain
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35
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Collin RWJ, van Strien D, Leunissen JAM, Martens GJM. Identification and expression of the first nonmammalian amyloid-beta precursor-like protein APLP2 in the amphibian Xenopus laevis. ACTA ACUST UNITED AC 2004; 271:1906-12. [PMID: 15128300 DOI: 10.1111/j.1432-1033.2004.04100.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The Alzheimer's disease-linked amyloid-beta precursor protein (APP) belongs to a superfamily of proteins, which also comprises the amyloid-beta precursor-like proteins, APLP1 and APLP2. Whereas APP has been identified in both lower and higher vertebrates, thus far, APLP1 and 2 have been characterized only in human and rodents. Here we identify the first nonmammalian APLP2 protein in the South African claw-toed frog Xenopus laevis. The identity between the Xenopus and mammalian APLP2 proteins is approximately 75%, with the highest degree of conservation in a number of amino-terminal regions, the transmembrane domain and the cytoplasmic tail. Furthermore, amino acid residues known to be phosphorylated and glycosylated in mammalian APLP2 are conserved in Xenopus. The availability of the Xenopus APLP2 protein sequence allowed a phylogenetic analysis of APP superfamily members that suggested the occurrence of APP and preAPLP lineages with their separation predating the mammalian-amphibian split. As in mammals, Xenopus APLP2 mRNA was ubiquitously expressed and alternatively spliced forms were detected. However, the expression ratios between the mRNA forms in the various tissues examined were different between Xenopus and mammals, most prominently for the alternatively spliced forms containing the Kunitz protease inhibitor-coding region that were less abundantly expressed than the corresponding mammalian forms. Thus, the identification of APLP2 in Xenopus has revealed evolutionarily conserved regions that may help to delineate functionally important domains, and its overall high degree of conservation suggests an important role for this APP superfamily member.
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Affiliation(s)
- Rob W J Collin
- Department of Molecular Animal Physiology, Nijmegen Center for Molecular Life Sciences (NCMLS), University of Nijmegen, The Netherlands
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36
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Engidawork E, Gulesserian T, Fountoulakis M, Lubec G. Aberrant protein expression in cerebral cortex of fetus with Down syndrome. Neuroscience 2004; 122:145-54. [PMID: 14596856 DOI: 10.1016/s0306-4522(03)00605-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Down syndrome is the most common birth defect associated with mental retardation. Identifying proteins that are aberrantly expressed therefore helps to understand how chromosomal imbalance leads to subnormal intelligence in Down syndrome. In the present study, we generated a fetal brain map with the use of an analytical method based on two-dimensional electrophoresis coupled with mass spectrometry and searched the proteome for differential protein expression. Among 49 proteins analyzed in seven control and nine Down syndrome fetuses, we found 11 proteins that have been deregulated in cerebral cortex of fetal Down syndrome. While double-strand break repair protein rad 21 homologue, eukaryotic translation initiation factor 3 subunit 5, mixed lineage leukemia septin-like fusion protein-B and heat shock protein 75 were increased; beta-amyloid precursor-like protein 1, tropomyosin 4-anaplastic lymphoma kinase fusion oncoprotein type 2, Nck adaptor protein 2, Src homology domain growth factor receptor bound 2-like endophilin B2, beta tubulin, septin 7 and hematopoietic stem/progenitor cells 140 were decreased. The current data suggest that misexpression of proteins that have functions ranging from signaling to cellular structural organization could contribute to or reflect brain dysgenesis in Down syndrome.
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Affiliation(s)
- E Engidawork
- Department of Neonatology, University of Vienna, Vienna, Austria
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37
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Ribaut-Barassin C, Dupont JL, Haeberlé AM, Bombarde G, Huber G, Moussaoui S, Mariani J, Bailly Y. Alzheimer's disease proteins in cerebellar and hippocampal synapses during postnatal development and aging of the rat. Neuroscience 2003; 120:405-23. [PMID: 12890511 DOI: 10.1016/s0306-4522(03)00332-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Alzheimer's dementia may be considered a synaptic disease of central neurons: the loss of synapses, reflected by early cognitive impairments, precedes the appearance of extra cellular focal deposits of beta-amyloid peptide in the brain of patients. Distinct immunocytochemical patterns of amyloid precursor proteins (APPs) have previously been demonstrated in the synapses by ultrastructural analysis in the cerebellum and hippocampus of adult rats and mice. Now we show that during postnatal development and during aging in these structures, the immunocytochemical expression of APPs increases in the synapses in parallel with the known up-regulation of total APPs brain levels. Interestingly, as shown previously in the adult rodents, the presenilins (PSs) 1 and 2, which intervene in APPs metabolism, exhibit a synaptic distribution pattern similar to that of APPs with parallel quantitative changes throughout life. In the brain tissue, single and double immunocytochemistry at the ultrastructural level shows co-localisation of APPs and PSs in axonal and dendritic synaptic compartments during postnatal synaptogenesis, adulthood and aging. In addition, double-labelling immunocytofluorescence detects these proteins close to synaptophysin at the growth cones of developing cultured neurons. Thusly, the brain expression of APPs and PSs appears to be regulated synchronously during lifespan in the synaptic compartments where the proteins are colocated. This suggests that PS-dependent processing of important synaptic proteins such as APPs could intervene in age-induced adjustments of synaptic relationships between specific types of neurons.
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Affiliation(s)
- C Ribaut-Barassin
- Neurotransmission et Sécrétion Neuroendocrine, UPR 2356 CNRS et IFR 37 des Neurosciences, 5 rue Blaise Pascal, 67084 Strasbourg, France
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38
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Scheinfeld MH, Ghersi E, Laky K, Fowlkes BJ, D'Adamio L. Processing of beta-amyloid precursor-like protein-1 and -2 by gamma-secretase regulates transcription. J Biol Chem 2002; 277:44195-201. [PMID: 12228233 DOI: 10.1074/jbc.m208110200] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The familial Alzheimer's disease gene product beta-amyloid (Abeta) precursor protein (APP) is processed by the beta- and gamma-secretases to produce Abeta as well as AID (APP Intracellular Domain) which is derived from the extreme carboxyl terminus of APP. AID was originally shown to lower the cellular threshold to apoptosis and more recently has been shown to modulate gene expression such that it represses Notch-dependent gene expression while in combination with Fe65 it enhances gene activation. Here we report that the two other members of the APP family, beta-amyloid precursor-like protein-1 and -2 (APLP1 and APLP2), are also processed by the gamma-secretase in a Presenilin 1-dependent manner. Furthermore, the extreme carboxyl-terminal fragments produced by this processing (here termed APP-like Intracellular Domain or ALID1 and ALID2) are able to enhance Fe65-dependent gene activation, similar to what has been reported for AID. Considering that only APP and not the APLPs have been linked to familial Alzheimer's disease (AD), this data should help in understanding the physiologic roles of the APP family members and in differentiating these functions from the pathologic role of APP in Alzheimer's disease.
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Affiliation(s)
- Meir H Scheinfeld
- Albert Einstein College of Medicine, Department of Microbiology and Immunology, Bronx, New York 10461, USA
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39
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Abstract
The amyloid precursor protein (APP) gene and its protein products have multiple functions in the central nervous system and fulfil criteria as neuractive peptides: presence, release and identity of action. There is increased understanding of the role of secretases (proteases) in the metabolism of APP and the production of its peptide fragments. The APP gene and its products have physiological roles in synaptic action, development of the brain, and in the response to stress and injury. These functions reveal the strategic importance of APP in the workings of the brain and point to its evolutionary significance.
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Affiliation(s)
- P K Panegyres
- Department of Neuropathology, Royal Perth Hospital, Western Australia.
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40
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Arendt T. Alzheimer's disease as a disorder of mechanisms underlying structural brain self-organization. Neuroscience 2001; 102:723-65. [PMID: 11182240 DOI: 10.1016/s0306-4522(00)00516-9] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mental function has as its cerebral basis a specific dynamic structure. In particular, cortical and limbic areas involved in "higher brain functions" such as learning, memory, perception, self-awareness and consciousness continuously need to be self-adjusted even after development is completed. By this lifelong self-optimization process, the cognitive, behavioural and emotional reactivity of an individual is stepwise remodelled to meet the environmental demands. While the presence of rigid synaptic connections ensures the stability of the principal characteristics of function, the variable configuration of the flexible synaptic connections determines the unique, non-repeatable character of an experienced mental act. With the increasing need during evolution to organize brain structures of increasing complexity, this process of selective dynamic stabilization and destabilization of synaptic connections becomes more and more important. These mechanisms of structural stabilization and labilization underlying a lifelong synaptic remodelling according to experience, are accompanied, however, by increasing inherent possibilities of failure and may, thus, not only allow for the evolutionary acquisition of "higher brain function" but at the same time provide the basis for a variety of neuropsychiatric disorders. It is the objective of the present paper to outline the hypothesis that it might be the disturbance of structural brain self-organization which, based on both genetic and epigenetic information, constantly "creates" and "re-creates" the brain throughout life, that is the defect that underlies Alzheimer's disease (AD). This hypothesis is, in particular, based on the following lines of evidence. (1) AD is a synaptic disorder. (2) AD is associated with aberrant sprouting at both the presynaptic (axonal) and postsynaptic (dendritic) site. (3) The spatial and temporal distribution of AD pathology follows the pattern of structural neuroplasticity in adulthood, which is a developmental pattern. (4) AD pathology preferentially involves molecules critical for the regulation of modifications of synaptic connections, i.e. "morphoregulatory" molecules that are developmentally controlled, such as growth-inducing and growth-associated molecules, synaptic molecules, adhesion molecules, molecules involved in membrane turnover, cytoskeletal proteins, etc. (5) Life events that place an additional burden on the plastic capacity of the brain or that require a particularly high plastic capacity of the brain might trigger the onset of the disease or might stimulate a more rapid progression of the disease. In other words, they might increase the risk for AD in the sense that they determine when, not whether, one gets AD. (6) AD is associated with a reactivation of developmental programmes that are incompatible with a differentiated cellular background and, therefore, lead to neuronal death. From this hypothesis, it can be predicted that a therapeutic intervention into these pathogenetic mechanisms is a particular challenge as it potentially interferes with those mechanisms that at the same time provide the basis for "higher brain function".
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Affiliation(s)
- T Arendt
- Paul Flechsig Institute of Brain Research, Department of Neuroanatomy, University of Leipzig, Jahnallee 59, D-04109, Leipzig, Germany.
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41
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Coulson EJ, Paliga K, Beyreuther K, Masters CL. What the evolution of the amyloid protein precursor supergene family tells us about its function. Neurochem Int 2000; 36:175-84. [PMID: 10676850 DOI: 10.1016/s0197-0186(99)00125-4] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Alzheimer's disease amyloid protein precursor (APP) gene is part of a multi-gene super-family from which sixteen homologous amyloid precursor-like proteins (APLP) and APP species homologues have been isolated and characterised. Comparison of exon structure (including the uncharacterised APL-1 gene), construction of phylogenetic trees, and analysis of the protein sequence alignment of known homologues of the APP super-family were performed to reconstruct the evolution of the family and to assess the functional significance of conserved protein sequences between homologues. This analysis supports an adhesion function for all members of the APP super family, with specificity determined by those sequences which are not conserved between APLP lineages, and provides evidence for an increasingly complex APP superfamily during evolution. The analysis also suggests that Drosophila APPL and Caenorhabditis elegans APL-1 may be a fourth APLP lineage indicating that these proteins, while not functional homologues of human APP, are similarly likely to regulate cell adhesion. Furthermore, the betaA4 sequence is highly conserved only in APP orthologues, strongly suggesting this sequence is of significant functional importance in this lineage.
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Affiliation(s)
- E J Coulson
- Department of Pathology, University of Melbourne and The Mental Health Research Institute, Parkville, Victoria, Australia.
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42
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Cappai R, Mok SS, Galatis D, Tucker DF, Henry A, Beyreuther K, Small DH, Masters CL. Recombinant human amyloid precursor-like protein 2 (APLP2) expressed in the yeast Pichia pastoris can stimulate neurite outgrowth. FEBS Lett 1999; 442:95-8. [PMID: 9923612 DOI: 10.1016/s0014-5793(98)01635-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The human amyloid precursor-like protein 2 (APLP2) is a member of the Alzheimer's disease amyloid precursor protein (APP) gene family. The human APLP2 ectodomain (sAPLP2) was expressed in the yeast Pichia pastoris and the recombinant sAPLP2 was purified from the culture medium in a single step by metal-chelating Sepharose chromatography. The neuritotrophic activity of APLP2 was compared to the APP isoforms sAPP695 and sAPP751 on chick sympathetic neurones. APLP2 had neurite outgrowth-promoting activity similar to that of the APP isoforms. This suggests that APP and APLP2 have a similar or related role and supports the idea of a redundancy in function between the APP-gene family proteins.
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Affiliation(s)
- R Cappai
- Department of Pathology, The University of Melbourne and The Mental Health Research Institute of Victoria, Parkville, Australia.
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43
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Harper SJ, Bilsland JG, Shearman MS, Zheng H, Van der Ploeg L, Sirinathsinghji DJ. Mouse cortical neurones lacking APP show normal neurite outgrowth and survival responses in vitro. Neuroreport 1998; 9:3053-8. [PMID: 9804315 DOI: 10.1097/00001756-199809140-00025] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We have cultured neurones from the developing cortex of mice that have had the amyloid precursor protein gene deleted (APP-null). Neurones cultured for a period of 24 h show similar neurite outgrowth and survival responses to wild-type neurones. Similar neurite outgrowth responses were also seen when neurones from APP-null mice were treated with a neurotrophic peptide derived from the APP sequence and compared with wild-type neurones. Finally, cortical cultures derived from APP-null mice showed similar survival responses to the toxic amyloid-beta peptide.
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Affiliation(s)
- S J Harper
- Department of Pharmacology, Merck, Sharp & Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex, UK
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44
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Breen KC, Coughlan CM, Hayes FD. The role of glycoproteins in neural development function, and disease. Mol Neurobiol 1998; 16:163-220. [PMID: 9588627 DOI: 10.1007/bf02740643] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Glycoproteins play key roles in the development, structuring, and subsequent functioning of the nervous system. However, the complex glycosylation process is a critical component in the biosynthesis of CNS glycoproteins that may be susceptible to the actions of toxicological agents or may be altered by genetic defects. This review will provide an outline of the complexity of this glycosylation process and of some of the key neural glycoproteins that play particular roles in neural development and in synaptic plasticity in the mature CNS. Finally, the potential of glycoproteins as targets for CNS disorders will be discussed.
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Affiliation(s)
- K C Breen
- Neurosciences Institute, Department of Pharmacology and Clinical Pharmacology, University of Dundee, Ninewells Hospital Medical School, Scotland, UK
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45
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Pekkarinen P, Hovatta I, Hakola P, Järvi O, Kestilä M, Lenkkeri U, Adolfsson R, Holmgren G, Nylander PO, Tranebjaerg L, Terwilliger JD, Lönnqvist J, Peltonen L. Assignment of the locus for PLO-SL, a frontal-lobe dementia with bone cysts, to 19q13. Am J Hum Genet 1998; 62:362-72. [PMID: 9463329 PMCID: PMC1376898 DOI: 10.1086/301722] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
PLO-SL (polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy) is a recessively inherited disorder characterized by systemic bone cysts and progressive presenile frontal-lobe dementia, resulting in death at <50 years of age. Since the 1960s, approximately 160 cases have been reported, mainly in Japan and Finland. The pathogenesis of the disease is unknown. In this article, we report the assignment of the locus for PLO-SL, by random genome screening using a modification of the haplotype-sharing method, in patients from a genetically isolated population. By screening five patient samples from 2 Finnish families, followed by linkage analysis of 12 Finnish families, 3 Swedish families, and 1 Norwegian family, we were able to assign the PLO-SL locus to a 9-cM interval between markers D19S191 and D19S420 on chromosome 19q13. The critical region was further restricted, to approximately 1.8 Mb, by linkage-disequilibrium analysis of the Finnish families. According to the haplotype analysis, one Swedish and one Norwegian PLO-SL family are not linked to the chromosome 19 locus, suggesting that PLO-SL is a heterogeneous disease. In this chromosomal region, one potential candidate gene for PLO-SL, the gene encoding amyloid precursor-like protein 1, was analyzed, but no mutations were detected in the coding region.
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Affiliation(s)
- P Pekkarinen
- Department of Human Molecular Genetics, Institute of Biomedicine, University of Helsinki, Helsinki, Finland
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46
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Ermekova KS, Chang A, Zambrano N, de Candia P, Russo T, Sudol M. Proteins Implicated In Alzheimer Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1998. [DOI: 10.1007/978-1-4615-4869-0_10] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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47
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Paliga K, Peraus G, Kreger S, Dürrwang U, Hesse L, Multhaup G, Masters CL, Beyreuther K, Weidemann A. Human amyloid precursor-like protein 1--cDNA cloning, ectopic expression in COS-7 cells and identification of soluble forms in the cerebrospinal fluid. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 250:354-63. [PMID: 9428684 DOI: 10.1111/j.1432-1033.1997.0354a.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Amyloid precursor-like protein 1 (APLP1) represents an integral membrane type 1 protein of unknown function which was originally cloned from a mouse cDNA library on the basis of sequence similarity with the Alzheimer's amyloid precursor protein (APP). Here we report on the molecular cloning and expression of the human APLP1 (hAPLP1). hAPLP1 consists of 650 amino acids, displays 89% identity on the amino acid level to its mouse homologue and has a calculated molecular mass of 72 kDa. hAPLP1 synthesized in a cell-free system displays an apparent molecular mass of approximately 80 kDa in SDS-containing gels and becomes N-glycosylated when the in vitro translation is performed in the presence of microsomes. The hAPLP1 cDNA was also expressed ectopically in COS-7 cells and the protein expression was analyzed by immunoprecipitation and western blotting. We have demonstrated that hAPLP1 represents a novel glycoprotein which carries both N- and O-linked glycans. Moreover, hAPLP1 undergoes limited proteolysis which results in the secretion of the carboxy-terminal truncated molecule into the cells conditioned medium. Examination of cells transfected with hAPLP1 cDNA by confocal laser microscopy reveals an intense perinuclear and Golgi staining, a pattern resembling the subcellular distribution of APP. Using a novel hAPLP1-specific antiserum, we identified soluble hAPLP1 in the human cerebrospinal fluid, which suggests that secretion of hAPLP1 from brain cells also takes place in vivo.
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Affiliation(s)
- K Paliga
- Center for Molecular Biology Heidelberg, Germany.
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48
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Affiliation(s)
- E B Ziff
- Howard Hughes Medical Institute, New York University Medical Center, Department of Biochemistry, New York, New York 10016, USA
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49
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Wu K, Aoki C, Elste A, Rogalski-Wilk AA, Siekevitz P. The synthesis of ATP by glycolytic enzymes in the postsynaptic density and the effect of endogenously generated nitric oxide. Proc Natl Acad Sci U S A 1997; 94:13273-8. [PMID: 9371836 PMCID: PMC24299 DOI: 10.1073/pnas.94.24.13273] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/1997] [Indexed: 02/05/2023] Open
Abstract
The major contribution of this paper is the finding of a glycolytic source of ATP in the isolated postsynaptic density (PSD). The enzymes involved in the generation of ATP are glyceraldehyde-3-phosphate dehydrogenase (G3PD) and phosphoglycerate kinase (PGK). Lactate dehydrogenase (LDH) is available for the regeneration of NAD+, as well as aldolase for the regeneration of glyceraldehyde-3-phosphate (G3P). The ATP was shown to be used by the PSD Ca2+/calmodulin-dependent protein kinase and can probably be used by two other PSD kinases, protein kinase A and protein kinase C. We confirmed by immunocytochemistry the presence of G3PD in the PSD and its binding to actin. Also present in the PSD is NO synthase, the source of NO. NO increases the binding of NAD, a G3PD cofactor, to G3PD and inhibits its activity as also found by others. The increased NAD binding resulted in an increase in G3PD binding to actin. We confirmed the autophosphorylation of G3PD by ATP, and further found that this procedure also increased the binding of G3PD to actin. ATP and NO are connected in that the formation of NO from NOS at the PSD resulted, in the presence of NAD, in a decrease of ATP formation in the PSD. In the discussion, we raise the possible roles of G3PD and of ATP in protein synthesis at the PSD, the regulation by NO, as well as the overall regulatory role of the PSD complex in synaptic transmission.
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Affiliation(s)
- K Wu
- Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey/Robert Wood Johnson Medical School, Piscataway 08854, USA
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50
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Beckman M, Iverfeldt K. Increased gene expression of beta-amyloid precursor protein and its homologues APLP1 and APLP2 in human neuroblastoma cells in response to retinoic acid. Neurosci Lett 1997; 221:73-6. [PMID: 9121703 DOI: 10.1016/s0304-3940(96)13292-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
beta-Amyloid precursor protein (APP) belongs to a family of homologous beta-amyloid precursor-like proteins (APLPs) including APLP1 and APLP2. Previously it has been shown that APP is subject to regulation by retinoic acid (RA). In this paper we show that APLP1 and APLP2 mRNA expression is upregulated during RA-induced differentiation of human SH-SY5Y neuroblastoma cells. The cells were treated with RA (10 microM) for 3 and 6 days and mRNA levels were analysed by a non-radioactive Northern blot assay. RA induced a 2- to 3-fold increase in the gene expression of both APLP2 and APP, whereas the increase in APLP1 mRNA expression was significantly higher. Our results support a role for APLPs during neuronal differentiation.
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Affiliation(s)
- M Beckman
- Department of Neurochemistry and Neurotoxicology, The Arrhenius Laboratories for Natural Sciences, Stockholm University, Sweden
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