1
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Wang J, Gleeson PA, Fourriere L. Spatial-Temporal Mapping Reveals the Golgi as the Major Processing Site for the Pathogenic Swedish APP Mutation: Familial APP Mutant Shifts the Major APP Processing Site. Traffic 2024; 25:e12932. [PMID: 38528836 DOI: 10.1111/tra.12932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 02/13/2024] [Accepted: 03/01/2024] [Indexed: 03/27/2024]
Abstract
Alzheimer's disease is associated with increased levels of amyloid beta (Aβ) generated by sequential intracellular cleavage of amyloid precursor protein (APP) by membrane-bound secretases. However, the spatial and temporal APP cleavage events along the trafficking pathways are poorly defined. Here, we use the Retention Using Selective Hooks (RUSH) to compare in real time the anterograde trafficking and temporal cleavage events of wild-type APP (APPwt) with the pathogenic Swedish APP (APPswe) and the disease-protective Icelandic APP (APPice). The analyses revealed differences in the trafficking profiles and processing between APPwt and the APP familial mutations. While APPwt was predominantly processed by the β-secretase, BACE1, following Golgi transport to the early endosomes, the transit of APPswe through the Golgi was prolonged and associated with enhanced amyloidogenic APP processing and Aβ secretion. A 20°C block in cargo exit from the Golgi confirmed β- and γ-secretase processing of APPswe in the Golgi. Inhibition of the β-secretase, BACE1, restored APPswe anterograde trafficking profile to that of APPwt. APPice was transported rapidly through the Golgi to the early endosomes with low levels of Aβ production. This study has revealed different intracellular locations for the preferential cleavage of APPwt and APPswe and Aβ production, and the Golgi as the major processing site for APPswe, findings relevant to understand the molecular basis of Alzheimer's disease.
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Affiliation(s)
- Jingqi Wang
- The Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Paul A Gleeson
- The Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
| | - Lou Fourriere
- The Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria, Australia
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2
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Zimmer VC, Lauer AA, Haupenthal V, Stahlmann CP, Mett J, Grösgen S, Hundsdörfer B, Rothhaar T, Endres K, Eckhardt M, Hartmann T, Grimm HS, Grimm MOW. A bidirectional link between sulfatide and Alzheimer's disease. Cell Chem Biol 2024; 31:265-283.e7. [PMID: 37972592 DOI: 10.1016/j.chembiol.2023.10.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 09/05/2023] [Accepted: 10/27/2023] [Indexed: 11/19/2023]
Abstract
Reduced sulfatide level is found in Alzheimer's disease (AD) patients. Here, we demonstrate that amyloid precursor protein (APP) processing regulates sulfatide synthesis and vice versa. Different cell culture models and transgenic mice models devoid of APP processing or in particular the APP intracellular domain (AICD) reveal that AICD decreases Gal3st1/CST expression and subsequently sulfatide synthesis. In return, sulfatide supplementation decreases Aβ generation by reducing β-secretase (BACE1) and γ-secretase processing of APP. Increased BACE1 lysosomal degradation leads to reduced BACE1 protein level in endosomes. Reduced γ-secretase activity is caused by a direct effect on γ-secretase activity and reduced amounts of γ-secretase components in lipid rafts. Similar changes were observed by analyzing cells and mice brain samples deficient of arylsulfatase A responsible for sulfatide degradation or knocked down in Gal3st1/CST. In line with these findings, addition of sulfatides to brain homogenates of AD patients resulted in reduced γ-secretase activity. Human brain APP level shows a significant negative correlation with GAL3ST1/CST expression underlining the in vivo relevance of sulfatide homeostasis in AD.
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Affiliation(s)
- Valerie Christin Zimmer
- Deutsches Institut für Demenzprävention (DIDP), Neurodegeneration and Neurobiology and Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany
| | - Anna Andrea Lauer
- Deutsches Institut für Demenzprävention (DIDP), Neurodegeneration and Neurobiology and Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany; Nutrition Therapy and Counseling, Campus Rheinland, SRH University of Applied Health Sciences, 51377 Leverkusen, Germany
| | - Viola Haupenthal
- Deutsches Institut für Demenzprävention (DIDP), Neurodegeneration and Neurobiology and Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany
| | - Christoph Peter Stahlmann
- Deutsches Institut für Demenzprävention (DIDP), Neurodegeneration and Neurobiology and Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany
| | - Janine Mett
- Deutsches Institut für Demenzprävention (DIDP), Neurodegeneration and Neurobiology and Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany; Biosciences Zoology/Physiology-Neurobiology, ZHMB (Center of Human and Molecular Biology), Faculty NT-Natural Science and Technology, Saarland University, 66123 Saarbrücken, Germany
| | - Sven Grösgen
- Deutsches Institut für Demenzprävention (DIDP), Neurodegeneration and Neurobiology and Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany
| | - Benjamin Hundsdörfer
- Deutsches Institut für Demenzprävention (DIDP), Neurodegeneration and Neurobiology and Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany
| | - Tatjana Rothhaar
- Deutsches Institut für Demenzprävention (DIDP), Neurodegeneration and Neurobiology and Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany
| | - Kristina Endres
- Department of Psychiatry and Psychotherapy, University Medical Center Johannes Gutenberg-University, 55099 Mainz, Germany
| | - Matthias Eckhardt
- Institute of Biochemistry and Molecular Biology, Medical Faculty, University of Bonn, 53115 Bonn, Germany
| | - Tobias Hartmann
- Deutsches Institut für Demenzprävention (DIDP), Neurodegeneration and Neurobiology and Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany
| | - Heike Sabine Grimm
- Deutsches Institut für Demenzprävention (DIDP), Neurodegeneration and Neurobiology and Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany; Nutrition Therapy and Counseling, Campus Rheinland, SRH University of Applied Health Sciences, 51377 Leverkusen, Germany
| | - Marcus Otto Walter Grimm
- Deutsches Institut für Demenzprävention (DIDP), Neurodegeneration and Neurobiology and Experimental Neurology, Saarland University, 66424 Homburg/Saar, Germany; Nutrition Therapy and Counseling, Campus Rheinland, SRH University of Applied Health Sciences, 51377 Leverkusen, Germany.
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3
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Papadopoulos N, Suelves N, Perrin F, Vadukul DM, Vrancx C, Constantinescu SN, Kienlen-Campard P. Structural Determinant of β-Amyloid Formation: From Transmembrane Protein Dimerization to β-Amyloid Aggregates. Biomedicines 2022; 10:2753. [PMID: 36359274 PMCID: PMC9687742 DOI: 10.3390/biomedicines10112753] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/18/2022] [Accepted: 10/21/2022] [Indexed: 10/03/2023] Open
Abstract
Most neurodegenerative diseases have the characteristics of protein folding disorders, i.e., they cause lesions to appear in vulnerable regions of the nervous system, corresponding to protein aggregates that progressively spread through the neuronal network as the symptoms progress. Alzheimer's disease is one of these diseases. It is characterized by two types of lesions: neurofibrillary tangles (NFTs) composed of tau proteins and senile plaques, formed essentially of amyloid peptides (Aβ). A combination of factors ranging from genetic mutations to age-related changes in the cellular context converge in this disease to accelerate Aβ deposition. Over the last two decades, numerous studies have attempted to elucidate how structural determinants of its precursor (APP) modify Aβ production, and to understand the processes leading to the formation of different Aβ aggregates, e.g., fibrils and oligomers. The synthesis proposed in this review indicates that the same motifs can control APP function and Aβ production essentially by regulating membrane protein dimerization, and subsequently Aβ aggregation processes. The distinct properties of these motifs and the cellular context regulate the APP conformation to trigger the transition to the amyloid pathology. This concept is critical to better decipher the patterns switching APP protein conformation from physiological to pathological and improve our understanding of the mechanisms underpinning the formation of amyloid fibrils that devastate neuronal functions.
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Affiliation(s)
- Nicolas Papadopoulos
- SIGN Unit, de Duve Institute, UCLouvain, 1200 Brussels, Belgium
- Ludwig Institute for Cancer Research Brussels, 1348 Brussels, Belgium
| | - Nuria Suelves
- Aging and Dementia Research Group, Cellular and Molecular (CEMO) Division, Institute of Neuroscience, UCLouvain, 1200 Brussels, Belgium
| | - Florian Perrin
- Memory Disorders Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Devkee M. Vadukul
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London SW7 2BX, UK
| | - Céline Vrancx
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, KU Leuven, 3000 Leuven, Belgium
- Department of Neurosciences, KU Leuven, 3000 Leuven, Belgium
| | - Stefan N. Constantinescu
- SIGN Unit, de Duve Institute, UCLouvain, 1200 Brussels, Belgium
- Ludwig Institute for Cancer Research Brussels, 1348 Brussels, Belgium
- Walloon Excellence in Life Sciences and Biotechnology (WELBIO), 1300 Wavre, Belgium
- Nuffield Department of Medicine, Ludwig Institute for Cancer Research, Oxford University, Oxford OX1 2JD, UK
| | - Pascal Kienlen-Campard
- Aging and Dementia Research Group, Cellular and Molecular (CEMO) Division, Institute of Neuroscience, UCLouvain, 1200 Brussels, Belgium
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4
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Cho Y, Bae HG, Okun E, Arumugam TV, Jo DG. Physiology and pharmacology of amyloid precursor protein. Pharmacol Ther 2022; 235:108122. [PMID: 35114285 DOI: 10.1016/j.pharmthera.2022.108122] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/17/2022] [Accepted: 01/25/2022] [Indexed: 02/06/2023]
Abstract
Amyloid precursor protein (APP) is an evolutionarily conserved transmembrane protein and a well-characterized precursor protein of amyloid-beta (Aβ) peptides, which accumulate in the brains of individuals with Alzheimer's disease (AD)-related pathologies. Aβ has been extensively investigated since the amyloid hypothesis in AD was proposed. Besides Aβ, previous studies on APP and its proteolytic cleavage products have suggested their diverse pathological and physiological functions. However, their roles still have not been thoroughly understood. In this review, we extensively discuss the evolutionarily-conserved biology of APP, including its structure and processing pathway, as well as recent findings on the physiological roles of APP and its fragments in the central nervous system and peripheral nervous system. We have also elaborated upon the current status of APP-targeted therapeutic approaches for AD treatment by discussing inhibitors of several proteases participating in APP processing, including α-, β-, and γ-secretases. Finally, we have highlighted the future perspectives pertaining to further research and the potential clinical role of APP.
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Affiliation(s)
- Yoonsuk Cho
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, South Korea
| | - Han-Gyu Bae
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, South Korea
| | - Eitan Okun
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan 5290002, Israel; The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 5290002, Israel; The Pauld Feder Laboratory on Alzheimer's Disease Research, Israel
| | - Thiruma V Arumugam
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, South Korea; School of Life Sciences, La Trobe University, Bundoora, Victoria, Australia.
| | - Dong-Gyu Jo
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, South Korea; Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul 06351, South Korea; Biomedical Institute for Convergence, Sungkyunkwan University, Suwon 16419, South Korea.
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5
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Smit T, Deshayes NAC, Borchelt DR, Kamphuis W, Middeldorp J, Hol EM. Reactive astrocytes as treatment targets in Alzheimer's disease-Systematic review of studies using the APPswePS1dE9 mouse model. Glia 2021; 69:1852-1881. [PMID: 33634529 PMCID: PMC8247905 DOI: 10.1002/glia.23981] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/04/2021] [Accepted: 02/08/2021] [Indexed: 12/15/2022]
Abstract
Astrocytes regulate synaptic communication and are essential for proper brain functioning. In Alzheimer's disease (AD) astrocytes become reactive, which is characterized by an increased expression of intermediate filament proteins and cellular hypertrophy. Reactive astrocytes are found in close association with amyloid-beta (Aβ) deposits. Synaptic communication and neuronal network function could be directly modulated by reactive astrocytes, potentially contributing to cognitive decline in AD. In this review, we focus on reactive astrocytes as treatment targets in AD in the APPswePS1dE9 AD mouse model, a widely used model to study amyloidosis and gliosis. We first give an overview of the model; that is, how it was generated, which cells express the transgenes, and the effect of its genetic background on Aβ pathology. Subsequently, to determine whether modifying reactive astrocytes in AD could influence pathogenesis and cognition, we review studies using this mouse model in which interventions were directly targeted at reactive astrocytes or had an indirect effect on reactive astrocytes. Overall, studies specifically targeting astrocytes to reduce astrogliosis showed beneficial effects on cognition, which indicates that targeting astrocytes should be included in developing novel therapies for AD.
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Affiliation(s)
- Tamar Smit
- Department of Translational NeuroscienceUniversity Medical Center Utrecht Brain Center, Utrecht UniversityUtrechtThe Netherlands
- Swammerdam Institute for Life SciencesCenter for Neuroscience, University of AmsterdamAmsterdamThe Netherlands
| | - Natasja A. C. Deshayes
- Department of Translational NeuroscienceUniversity Medical Center Utrecht Brain Center, Utrecht UniversityUtrechtThe Netherlands
- Swammerdam Institute for Life SciencesCenter for Neuroscience, University of AmsterdamAmsterdamThe Netherlands
| | - David R. Borchelt
- Center for Translational Research in Neurodegenerative Disease, McKnight Brain Institute, Department of NeuroscienceUniversity of Florida College of MedicineGainesvilleFloridaUSA
| | - Willem Kamphuis
- Netherlands Institute for NeuroscienceAn Institute of the Royal Netherlands Academy of Arts and SciencesAmsterdamThe Netherlands
| | - Jinte Middeldorp
- Department of Translational NeuroscienceUniversity Medical Center Utrecht Brain Center, Utrecht UniversityUtrechtThe Netherlands
- Department of ImmunobiologyBiomedical Primate Research CentreRijswijkThe Netherlands
| | - Elly M. Hol
- Department of Translational NeuroscienceUniversity Medical Center Utrecht Brain Center, Utrecht UniversityUtrechtThe Netherlands
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6
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Augustin V, Kins S. Fe65: A Scaffolding Protein of Actin Regulators. Cells 2021; 10:cells10071599. [PMID: 34202290 PMCID: PMC8304848 DOI: 10.3390/cells10071599] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/19/2021] [Accepted: 06/21/2021] [Indexed: 01/19/2023] Open
Abstract
The scaffolding protein family Fe65, composed of Fe65, Fe65L1, and Fe65L2, was identified as an interaction partner of the amyloid precursor protein (APP), which plays a key function in Alzheimer’s disease. All three Fe65 family members possess three highly conserved interaction domains, forming complexes with diverse binding partners that can be assigned to different cellular functions, such as transactivation of genes in the nucleus, modulation of calcium homeostasis and lipid metabolism, and regulation of the actin cytoskeleton. In this article, we rule out putative new intracellular signaling mechanisms of the APP-interacting protein Fe65 in the regulation of actin cytoskeleton dynamics in the context of various neuronal functions, such as cell migration, neurite outgrowth, and synaptic plasticity.
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7
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Pérez-González R, Kim Y, Miller C, Pacheco-Quinto J, Eckman EA, Levy E. Extracellular vesicles: where the amyloid precursor protein carboxyl-terminal fragments accumulate and amyloid-β oligomerizes. FASEB J 2020; 34:12922-12931. [PMID: 32772431 PMCID: PMC7496786 DOI: 10.1096/fj.202000823r] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/11/2020] [Accepted: 07/20/2020] [Indexed: 12/20/2022]
Abstract
Pleiotropic roles are proposed for brain extracellular vesicles (EVs) in the development of Alzheimer's disease (AD). Our previous studies have suggested a beneficial role for EVs in AD, where the endosomal system in vulnerable neurons is compromised, contributing to the removal of accumulated material from neurons. However, the involvement of EVs in propagating AD amyloidosis throughout the brain has been considered because the amyloid‐β precursor protein (APP), APP metabolites, and key APP cleaving enzymes were identified in association with EVs. Here, we undertook to determine whether the secretase machinery is actively processing APP in EVs isolated from the brains of wild‐type and APP overexpressing Tg2576 mice. We found that full‐length APP is cleaved in EVs incubated in the absence of cells. The resulting metabolites, both α‐ and β‐APP carboxyl‐terminal fragments and APP intracellular domain accumulate in EVs over time and amyloid‐β dimerizes. Thus, EVs contribute to the removal from neurons and transport of APP‐derived neurotoxic peptides. While this is potentially a venue for propagation of the pathology throughout the brain, it may contribute to efficient removal of neurotoxic peptides from the brain.
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Affiliation(s)
- Rocío Pérez-González
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA.,Department of Psychiatry, New York University School of Medicine, New York, NY, USA
| | - Yohan Kim
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA.,Department of Psychiatry, New York University School of Medicine, New York, NY, USA
| | - Chelsea Miller
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - Javier Pacheco-Quinto
- Biomedical Research Institute of New Jersey, Cedar Knolls, and Atlantic Health Systems, Morristown, NJ, USA
| | - Elizabeth A Eckman
- Biomedical Research Institute of New Jersey, Cedar Knolls, and Atlantic Health Systems, Morristown, NJ, USA
| | - Efrat Levy
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA.,Department of Psychiatry, New York University School of Medicine, New York, NY, USA.,Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA.,Neuroscience Institute, New York University School of Medicine, New York, NY, USA
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8
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Effect of memantine on expression of Bace1-as and Bace1 genes in STZ-induced Alzheimeric rats. Mol Biol Rep 2020; 47:5737-5745. [PMID: 32648077 DOI: 10.1007/s11033-020-05629-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 06/26/2020] [Indexed: 01/05/2023]
Abstract
Recent studies have showed that the long non-coding RNAs (lncRNAs) expression is dysregulated in different neurodegenerative disorders like Alzheimer's disease (AD). In the present study, the effects of memantine on the level of Bace1-as and Bace1 genes' expression in streptozotocin (STZ)-induced Alzheimer's and memantine treated rats were investigated. The male Wistar rats were randomly divided into four groups: 1-Normal control, 2-Sham-operated control, 3- Alzheimer'scontrol rats (ICV-STZ), 4-Experimental group rats treated by memantine in a dose of 30 mg/kg/day for 28 days in ICV-STZ rats. The expression of Bace1-as and Bace1 genes was measured by quantitative-PCR in the brain and blood tissues. ELISA was used to analyze Bace1 and Aβ proteins. Expression of Bace1-as was significantly increased in the brain and blood tissues of the experimental group (p = 0.032 and p = 0.034, respectively). The expression of Bace1 gene showed no significant changes in the brain. Furthermore, the ELISA analysis revealed that Bace1 protein was significantly increased in the plasma of the Alzheimer's control group (p = 0.000) and in the brain tissue of the experimental group (p = 0.000). Additionally, Aβ levels had no significant changes between all groups studied. The Bace1 protein may be used as a prognostic biomarker in plasma, or before using memantine as a treatment. Furthermore, Bace1-as gene expression may play a role in monitoring the progression of AD.
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9
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Lee YJ, Ch'ng TH. RIP at the Synapse and the Role of Intracellular Domains in Neurons. Neuromolecular Med 2019; 22:1-24. [PMID: 31346933 DOI: 10.1007/s12017-019-08556-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/12/2019] [Indexed: 12/18/2022]
Abstract
Regulated intramembrane proteolysis (RIP) occurs in a cell when transmembrane proteins are cleaved by intramembrane proteases such as secretases to generate soluble protein fragments in the extracellular environment and the cytosol. In the cytosol, these soluble intracellular domains (ICDs) have local functions near the site of cleavage or in many cases, translocate to the nucleus to modulate gene expression. While the mechanism of RIP is relatively well studied, the fate and function of ICDs for most substrate proteins remain poorly characterized. In neurons, RIP occurs in various subcellular compartments including at the synapse. In this review, we summarize current research on RIP in neurons, focusing specifically on synaptic proteins where the presence and function of the ICDs have been reported. We also briefly discuss activity-driven processing of RIP substrates at the synapse and the cellular machinery that support long-distance transport of ICDs from the synapse to the nucleus. Finally, we describe future challenges in this field of research in the context of understanding the contribution of ICDs in neuronal function.
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Affiliation(s)
- Yan Jun Lee
- Lee Kong Chian School of Medicine, Nanyang Technological University, Clinical Science Building, 11 Mandalay Road, 10-01-01 M, Singapore, 308232, Singapore.,Interdisciplinary Graduate School (IGS), Nanyang Technological University, Singapore, Singapore
| | - Toh Hean Ch'ng
- Lee Kong Chian School of Medicine, Nanyang Technological University, Clinical Science Building, 11 Mandalay Road, 10-01-01 M, Singapore, 308232, Singapore. .,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
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10
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Profiling of Alzheimer’s disease related genes in mild to moderate vitamin D hypovitaminosis. J Nutr Biochem 2019; 67:123-137. [DOI: 10.1016/j.jnutbio.2019.01.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 12/13/2018] [Accepted: 01/29/2019] [Indexed: 02/01/2023]
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11
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Castro MA, Hadziselimovic A, Sanders CR. The vexing complexity of the amyloidogenic pathway. Protein Sci 2019; 28:1177-1193. [PMID: 30897251 DOI: 10.1002/pro.3606] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 03/18/2019] [Accepted: 03/18/2019] [Indexed: 02/06/2023]
Abstract
The role of the amyloidogenic pathway in the etiology of Alzheimer's disease (AD), particularly the common sporadic late onset forms of the disease, is controversial. To some degree, this is a consequence of the failure of drug and therapeutic antibody trials based either on targeting the proteases in this pathway or its amyloid end products. Here, we explore the formidable complexity of the biochemistry and cell biology associated with this pathway. For example, we review evidence that the immediate precursor of amyloid-β, the C99 domain of the amyloid precursor protein (APP), may itself be toxic. We also review important new results that appear to finally establish a direct genetic link between mutations in APP and the sporadic forms of AD. Based on the complexity of amyloidogenesis, it seems possible that a major contributor to the failure of related drug trials is that we have an incomplete understanding of this pathway and how it is linked to Alzheimer's pathogenesis. If so, this highlights a need for further characterization of this pathway, not its abandonment.
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Affiliation(s)
- Manuel A Castro
- Departments of Biochemistry and Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37240
| | - Arina Hadziselimovic
- Departments of Biochemistry and Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37240
| | - Charles R Sanders
- Departments of Biochemistry and Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37240
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12
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Steiner H, Fukumori A, Tagami S, Okochi M. Making the final cut: pathogenic amyloid-β peptide generation by γ-secretase. Cell Stress 2018; 2:292-310. [PMID: 31225454 PMCID: PMC6551803 DOI: 10.15698/cst2018.11.162] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alzheimer´s disease (AD) is a devastating neurodegenerative disease of the elderly population. Genetic evidence strongly suggests that aberrant generation and/or clearance of the neurotoxic amyloid-β peptide (Aβ) is triggering the disease. Aβ is generated from the amyloid precursor protein (APP) by the sequential cleavages of β- and γ-secretase. The latter cleavage by γ-secretase, a unique and fascinating four-component protease complex, occurs in the APP transmembrane domain thereby releasing Aβ species of 37-43 amino acids in length including the longer, highly pathogenic peptides Aβ42 and Aβ43. The lack of a precise understanding of Aβ generation as well as of the functions of other γ-secretase substrates has been one factor underlying the disappointing failure of γ-secretase inhibitors in clinical trials, but on the other side also been a major driving force for structural and in depth mechanistic studies on this key AD drug target in the past few years. Here we review recent breakthroughs in our understanding of how the γ-secretase complex recognizes substrates, of how it binds and processes β-secretase cleaved APP into different Aβ species, as well as the progress made on a question of outstanding interest, namely how clinical AD mutations in the catalytic subunit presenilin and the γ-secretase cleavage region of APP lead to relative increases of Aβ42/43. Finally, we discuss how the knowledge emerging from these studies could be used to therapeutically target this enzyme in a safe way.
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Affiliation(s)
- Harald Steiner
- Biomedical Center (BMC), Metabolic Biochemistry, Ludwig-Maximilians-University Munich, Germany.,German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Akio Fukumori
- Department of Aging Neurobiology, National Center for Geriatrics and Gerontology, Obu & Department of Mental Health Promotion, Osaka University Graduate School of Medicine, Toyonaka, Japan
| | - Shinji Tagami
- Neuropsychiatry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masayasu Okochi
- Neuropsychiatry, Department of Integrated Medicine, Division of Internal Medicine, Osaka University Graduate School of Medicine, Suita, Japan
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13
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Matsuda S, Senda T. BRI2 as an anti-Alzheimer gene. Med Mol Morphol 2018; 52:1-7. [DOI: 10.1007/s00795-018-0191-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 04/18/2018] [Indexed: 12/16/2022]
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14
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Contino S, Porporato PE, Bird M, Marinangeli C, Opsomer R, Sonveaux P, Bontemps F, Dewachter I, Octave JN, Bertrand L, Stanga S, Kienlen-Campard P. Presenilin 2-Dependent Maintenance of Mitochondrial Oxidative Capacity and Morphology. Front Physiol 2017; 8:796. [PMID: 29085303 PMCID: PMC5650731 DOI: 10.3389/fphys.2017.00796] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 09/28/2017] [Indexed: 12/19/2022] Open
Abstract
Mitochondrial dysfunction plays a pivotal role in the progression of Alzheimer's disease (AD), and yet the mechanisms underlying the impairment of mitochondrial function in AD remain elusive. Recent evidence suggested a role for Presenilins (PS1 or PS2) in mitochondrial function. Mutations of PSs, the catalytic subunits of the γ-secretase complex, are responsible for the majority of inherited AD cases (FAD). PSs were shown to be present in mitochondria and particularly enriched in mitochondria-associated membranes (MAM), where PS2 is involved in the calcium shuttling between mitochondria and the endoplasmic reticulum (ER). We investigated the precise contribution of PS1 and PS2 to the bioenergetics of the cell and to mitochondrial morphology in cell lines derived from wild type (PS+/+), PS1/2 double knock-out (PSdKO), PS2KO and PS1KO embryos. Our results showed a significant impairment in the respiratory capacity of PSdKO and PS2KO cells with reduction of basal oxygen consumption, oxygen utilization dedicated to ATP production and spare respiratory capacity. In line with these functional defects, we found a decrease in the expression of subunits responsible for mitochondrial oxidative phosphorylation (OXPHOS) associated with an altered morphology of the mitochondrial cristae. This OXPHOS disruption was accompanied by a reduction of the NAD+/NADH ratio. Still, neither ADP/ATP ratio nor mitochondrial membrane potential (ΔΨ) were affected, suggesting the existence of a compensatory mechanism for energetic balance. We observed indeed an increase in glycolytic flux in PSdKO and PS2KO cells. All these effects were truly dependent on PS2 since its stable re-expression in a PS2KO background led to a complete restoration of the parameters impaired in the absence of PS2. Our data clearly demonstrate here the crucial role of PS2 in mitochondrial function and cellular bioenergetics, pointing toward its peculiar role in the formation and integrity of the electron transport chain.
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Affiliation(s)
- Sabrina Contino
- Alzheimer Research Group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Paolo E Porporato
- Pharmacology and Therapeutics, Institute of Experimental and Clinical Research, Université catholique de Louvain, Brussels, Belgium
| | - Matthew Bird
- Alzheimer Research Group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Claudia Marinangeli
- Alzheimer Research Group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Rémi Opsomer
- Alzheimer Research Group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Pierre Sonveaux
- Pharmacology and Therapeutics, Institute of Experimental and Clinical Research, Université catholique de Louvain, Brussels, Belgium
| | - Françoise Bontemps
- Metabolic Research Group, de Duve Institute, Université catholique de Louvain, Brussels, Belgium
| | - Ilse Dewachter
- Alzheimer Research Group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Jean-Noël Octave
- Alzheimer Research Group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Luc Bertrand
- Pole of Cardiovascular Research, Institute of Experimental and clinical Research, Université catholique de Louvain, Brussels, Belgium
| | - Serena Stanga
- Alzheimer Research Group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Pascal Kienlen-Campard
- Alzheimer Research Group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
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15
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Stanga S, Vrancx C, Tasiaux B, Marinangeli C, Karlström H, Kienlen-Campard P. Specificity of presenilin-1- and presenilin-2-dependent γ-secretases towards substrate processing. J Cell Mol Med 2017; 22:823-833. [PMID: 28994238 PMCID: PMC5783875 DOI: 10.1111/jcmm.13364] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 07/27/2017] [Indexed: 12/20/2022] Open
Abstract
The two presenilin‐1 (PS1) and presenilin‐2 (PS2) homologs are the catalytic core of the γ‐secretase complex, which has a major role in cell fate decision and Alzheimer's disease (AD) progression. Understanding the precise contribution of PS1‐ and PS2‐dependent γ‐secretases to the production of β‐amyloid peptide (Aβ) from amyloid precursor protein (APP) remains an important challenge to design molecules efficiently modulating Aβ release without affecting the processing of other γ‐secretase substrates. To that end, we studied PS1‐ and PS2‐dependent substrate processing in murine cells lacking presenilins (PSs) (PS1KO, PS2KO or PS1‐PS2 double‐KO noted PSdKO) or stably re‐expressing human PS1 or PS2 in an endogenous PS‐null (PSdKO) background. We characterized the processing of APP and Notch on both endogenous and exogenous substrates, and we investigated the effect of pharmacological inhibitors targeting the PSs activity (DAPT and L‐685,458). We found that murine PS1 γ‐secretase plays a predominant role in APP and Notch processing when compared to murine PS2 γ‐secretase. The inhibitors blocked more efficiently murine PS2‐ than murine PS1‐dependent processing. Human PSs, especially human PS1, expression in a PS‐null background efficiently restored APP and Notch processing. Strikingly, and contrary to the results obtained on murine PSs, pharmacological inhibitors appear to preferentially target human PS1‐ than human PS2‐dependent γ‐secretase activity.
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Affiliation(s)
- Serena Stanga
- Alzheimer Research group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Céline Vrancx
- Alzheimer Research group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Bernadette Tasiaux
- Alzheimer Research group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Claudia Marinangeli
- Inserm, CHU Lille, UMR-S 1172 - JPArc - Centre de Recherche Jean-Pierre AUBERT, University of Lille, Lille, France
| | - Helena Karlström
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institute, Stockholm, Sweden
| | - Pascal Kienlen-Campard
- Alzheimer Research group, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
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16
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Small things matter: Implications of APP intracellular domain AICD nuclear signaling in the progression and pathogenesis of Alzheimer’s disease. Prog Neurobiol 2017; 156:189-213. [DOI: 10.1016/j.pneurobio.2017.05.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/25/2017] [Accepted: 05/30/2017] [Indexed: 01/08/2023]
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17
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Pousinha PA, Mouska X, Raymond EF, Gwizdek C, Dhib G, Poupon G, Zaragosi LE, Giudici C, Bethus I, Pacary E, Willem M, Marie H. Physiological and pathophysiological control of synaptic GluN2B-NMDA receptors by the C-terminal domain of amyloid precursor protein. eLife 2017; 6. [PMID: 28682239 PMCID: PMC5544428 DOI: 10.7554/elife.25659] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 07/05/2017] [Indexed: 12/11/2022] Open
Abstract
The amyloid precursor protein (APP) harbors physiological roles at synapses and is central to Alzheimer’s disease (AD) pathogenesis. Evidence suggests that APP intracellular domain (AICD) could regulate synapse function, but the underlying molecular mechanisms remain unknown. We addressed AICD actions at synapses, per se, combining in vivo AICD expression, ex vivo AICD delivery or APP knock-down by in utero electroporation of shRNAs with whole-cell electrophysiology. We report a critical physiological role of AICD in controlling GluN2B-containing NMDA receptors (NMDARs) at immature excitatory synapses, via a transcription-dependent mechanism. We further show that AICD increase in mature neurons, as reported in AD, alters synaptic NMDAR composition to an immature-like GluN2B-rich profile. This disrupts synaptic signal integration, via over-activation of SK channels, and synapse plasticity, phenotypes rescued by GluN2B antagonism. We provide a new physiological role for AICD, which becomes pathological upon AICD increase in mature neurons. Thus, AICD could contribute to AD synaptic failure. DOI:http://dx.doi.org/10.7554/eLife.25659.001
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Affiliation(s)
- Paula A Pousinha
- Team Molecular Mechanisms of neuronal plasticity in health and disease, Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Nice Sophia Antipolis, Nice, France
| | - Xavier Mouska
- Team Molecular Mechanisms of neuronal plasticity in health and disease, Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Nice Sophia Antipolis, Nice, France
| | - Elisabeth F Raymond
- Team Molecular Mechanisms of neuronal plasticity in health and disease, Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Nice Sophia Antipolis, Nice, France
| | - Carole Gwizdek
- Team SUMOylation in neuronal function and dysfunction, Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Nice Sophia Antipolis, Nice, France
| | - Gihen Dhib
- Team Molecular Mechanisms of neuronal plasticity in health and disease, Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Nice Sophia Antipolis, Nice, France
| | - Gwenola Poupon
- Team SUMOylation in neuronal function and dysfunction, Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Nice Sophia Antipolis, Nice, France
| | - Laure-Emmanuelle Zaragosi
- Team Physiological genomics of the eukaryotes, Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Nice Sophia Antipolis, Nice, France
| | | | - Ingrid Bethus
- Team Molecular Mechanisms of neuronal plasticity in health and disease, Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Nice Sophia Antipolis, Nice, France
| | - Emilie Pacary
- INSERM U1215, Neurocentre Magendie, France et Université de Bordeaux, Bordeaux, France
| | | | - Hélène Marie
- Team Molecular Mechanisms of neuronal plasticity in health and disease, Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Université de Nice Sophia Antipolis, Nice, France
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18
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Chiarini A, Armato U, Liu D, Dal Prà I. Calcium-Sensing Receptor Antagonist NPS 2143 Restores Amyloid Precursor Protein Physiological Non-Amyloidogenic Processing in Aβ-Exposed Adult Human Astrocytes. Sci Rep 2017; 7:1277. [PMID: 28455519 PMCID: PMC5430644 DOI: 10.1038/s41598-017-01215-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 03/27/2017] [Indexed: 12/11/2022] Open
Abstract
Physiological non-amyloidogenic processing (NAP) of amyloid precursor holoprotein (hAPP) by α-secretases (e.g., ADAM10) extracellularly sheds neurotrophic/neuroprotective soluble (s)APPα and precludes amyloid-β peptides (Aβs) production via β-secretase amyloidogenic processing (AP). Evidence exists that Aβs interact with calcium-sensing receptors (CaSRs) in human astrocytes and neurons, driving the overrelease of toxic Aβ42/Aβ42-os (oligomers), which is completely blocked by CaSR antagonist (calcilytic) NPS 2143. Here, we investigated the mechanisms underlying NPS 2143 beneficial effects in human astrocytes. Moreover, because Alzheimer's disease (AD) involves neuroinflammation, we examined whether NPS 2143 remained beneficial when both fibrillary (f)Aβ25-35 and a microglial cytokine mixture (CMT) were present. Thus, hAPP NAP prevailed over AP in untreated astrocytes, which extracellularly shed all synthesized sAPPα while secreting basal Aβ40/42 amounts. Conversely, fAβ25-35 alone dramatically reduced sAPPα extracellular shedding while driving Aβ42/Aβ42-os oversecretion that CMT accelerated but not increased, despite a concurring hAPP overexpression. NPS 2143 promoted hAPP and ADAM10 translocation to the plasma membrane, thereby restoring sAPPα extracellular shedding and fully suppressing any Aβ42/Aβ42-os oversecretion, but left hAPP expression unaffected. Therefore, as anti-AD therapeutics calcilytics support neuronal viability by safeguarding astrocytes neurotrophic/neuroprotective sAPPα shedding, suppressing neurons and astrocytes Aβ42/Aβ42-os build-up/secretion, and remaining effective even under AD-typical neuroinflammatory conditions.
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Affiliation(s)
- Anna Chiarini
- Human Histology & Embryology Unit, Medical School, University of Verona, Verona, Venetia, Italy.
| | - Ubaldo Armato
- Human Histology & Embryology Unit, Medical School, University of Verona, Verona, Venetia, Italy
| | - Daisong Liu
- The Third Xiangya Hospital of Central South University, Department of Plastic Surgery, Changsha, Hunan, China
| | - Ilaria Dal Prà
- Human Histology & Embryology Unit, Medical School, University of Verona, Verona, Venetia, Italy.
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Guénette S, Strecker P, Kins S. APP Protein Family Signaling at the Synapse: Insights from Intracellular APP-Binding Proteins. Front Mol Neurosci 2017; 10:87. [PMID: 28424586 PMCID: PMC5371672 DOI: 10.3389/fnmol.2017.00087] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 03/13/2017] [Indexed: 12/17/2022] Open
Abstract
Understanding the molecular mechanisms underlying amyloid precursor protein family (APP/APP-like proteins, APLP) function in the nervous system can be achieved by studying the APP/APLP interactome. In this review article, we focused on intracellular APP interacting proteins that bind the YENPTY internalization motif located in the last 15 amino acids of the C-terminal region. These proteins, which include X11/Munc-18-interacting proteins (Mints) and FE65/FE65Ls, represent APP cytosolic binding partners exhibiting different neuronal functions. A comparison of FE65 and APP family member mutant mice revealed a shared function for APP/FE65 protein family members in neurogenesis and neuronal positioning. Accumulating evidence also supports a role for membrane-associated APP/APLP proteins in synapse formation and function. Therefore, it is tempting to speculate that APP/APLP C-terminal interacting proteins transmit APP/APLP-dependent signals at the synapse. Herein, we compare our current knowledge of the synaptic phenotypes of APP/APLP mutant mice with those of mice lacking different APP/APLP interaction partners and discuss the possible downstream effects of APP-dependent FE65/FE65L or X11/Mint signaling on synaptic vesicle release, synaptic morphology and function. Given that the role of X11/Mint proteins at the synapse is well-established, we propose a model highlighting the role of FE65 protein family members for transduction of APP/APLP physiological function at the synapse.
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Affiliation(s)
| | - Paul Strecker
- Department of Biology, Division of Human Biology, University of KaiserslauternKaiserslautern, Germany
| | - Stefan Kins
- Department of Biology, Division of Human Biology, University of KaiserslauternKaiserslautern, Germany
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20
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Membrane tethering of APP c-terminal fragments is a prerequisite for T668 phosphorylation preventing nuclear sphere generation. Cell Signal 2016; 28:1725-34. [DOI: 10.1016/j.cellsig.2016.08.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 08/12/2016] [Accepted: 08/12/2016] [Indexed: 01/11/2023]
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21
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Extensive nuclear sphere generation in the human Alzheimer's brain. Neurobiol Aging 2016; 48:103-113. [PMID: 27644079 DOI: 10.1016/j.neurobiolaging.2016.08.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 08/16/2016] [Accepted: 08/18/2016] [Indexed: 10/21/2022]
Abstract
Nuclear spheres are protein aggregates consisting of FE65, TIP60, BLM, and other yet unknown proteins. Generation of these structures in the cellular nucleus is putatively modulated by the amyloid precursor protein (APP), either by its cleavage or its phosphorylation. Nuclear spheres were preferentially studied in cell culture models and their existence in the human brain had not been known. Existence of nuclear spheres in the human brain was studied using immunohistochemistry. Cell culture experiments were used to study regulative mechanisms of nuclear sphere generation. The comparison of human frontal cortex brain samples from Alzheimer's disease (AD) patients to age-matched controls revealed a dramatically and highly significant enrichment of nuclear spheres in the AD brain. Costaining demonstrated that neurons are distinctly affected by nuclear spheres, but astrocytes never are. Nuclear spheres were predominantly found in neurons that were negative for threonine 668 residue in APP phosphorylation. Cell culture experiments revealed that JNK3-mediated APP phosphorylation reduces the amount of sphere-positive cells. The study suggests that nuclear spheres are a new APP-derived central hallmark of AD, which might be of crucial relevance for the molecular mechanisms in neurodegeneration.
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Ghosal K, Fan Q, Dawson HN, Pimplikar SW. Tau Protein Mediates APP Intracellular Domain (AICD)-Induced Alzheimer's-Like Pathological Features in Mice. PLoS One 2016; 11:e0159435. [PMID: 27459671 PMCID: PMC4961442 DOI: 10.1371/journal.pone.0159435] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 07/01/2016] [Indexed: 11/20/2022] Open
Abstract
Amyloid precursor protein (APP) is cleaved by gamma-secretase to simultaneously generate amyloid beta (Aβ) and APP Intracellular Domain (AICD) peptides. Aβ plays a pivotal role in Alzheimer's disease (AD) pathogenesis but recent studies suggest that amyloid-independent mechanisms also contribute to the disease. We previously showed that AICD transgenic mice (AICD-Tg) exhibit AD-like features such as tau pathology, aberrant neuronal activity, memory deficits and neurodegeneration in an age-dependent manner. Since AD is a tauopathy and tau has been shown to mediate Aβ-induced toxicity, we examined the role of tau in AICD-induced pathological features. We report that ablating endogenous tau protects AICD-Tg mice from deficits in adult neurogenesis, seizure severity, short-term memory deficits and neurodegeneration. Deletion of tau restored abnormal phosphorylation of NMDA receptors, which is likely to underlie hyperexcitability and associated excitotoxicity in AICD-Tg mice. Conversely, overexpression of wild-type human tau aggravated receptor phosphorylation, impaired adult neurogenesis, memory deficits and neurodegeneration. Our findings show that tau is essential for mediating the deleterious effects of AICD. Since tau also mediates Aβ-induced toxic effects, our findings suggest that tau is a common downstream factor in both amyloid-dependent and-independent pathogenic mechanisms and therefore could be a more effective drug target for therapeutic intervention in AD.
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Affiliation(s)
- Kaushik Ghosal
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195, United States of America
| | - Qingyuan Fan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195, United States of America
| | - Hana N. Dawson
- Department of Neurology, Duke University, Durham, North Carolina, 27710, United States of America
| | - Sanjay W. Pimplikar
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195, United States of America
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23
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CHEN QING, LIU XINGHUI, XU LIMIN, WANG YING, WANG SUWEI, LI QIONG, HUANG YONGYI, LIU TE. Long non-coding RNA BACE1-AS is a novel target for anisomycin-mediated suppression of ovarian cancer stem cell proliferation and invasion. Oncol Rep 2016; 35:1916-24. [DOI: 10.3892/or.2016.4571] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 12/16/2015] [Indexed: 11/06/2022] Open
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24
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Loosse C, Pawlas M, Bukhari HS, Maghnouj A, Hahn S, Marcus K, Müller T. Nuclear spheres modulate the expression of BEST1 and GADD45G. Cell Signal 2016; 28:100-9. [DOI: 10.1016/j.cellsig.2015.10.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 10/19/2015] [Accepted: 10/27/2015] [Indexed: 11/28/2022]
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25
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Stanga S, Zanou N, Audouard E, Tasiaux B, Contino S, Vandermeulen G, René F, Loeffler JP, Clotman F, Gailly P, Dewachter I, Octave JN, Kienlen-Campard P. APP-dependent glial cell line-derived neurotrophic factor gene expression drives neuromuscular junction formation. FASEB J 2015; 30:1696-711. [PMID: 26718890 DOI: 10.1096/fj.15-278739] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 12/08/2015] [Indexed: 12/13/2022]
Abstract
Besides its crucial role in the pathogenesis of Alzheimer's disease, the knowledge of amyloid precursor protein (APP) physiologic functions remains surprisingly scarce. Here, we show that APP regulates the transcription of the glial cell line-derived neurotrophic factor (GDNF). APP-dependent regulation of GDNF expression affects muscle strength, muscular trophy, and both neuronal and muscular differentiation fundamental for neuromuscular junction (NMJ) maturation in vivo In a nerve-muscle coculture model set up to modelize NMJ formation in vitro, silencing of muscular APP induces a 30% decrease in secreted GDNF levels and a 40% decrease in the total number of NMJs together with a significant reduction in the density of acetylcholine vesicles at the presynaptic site and in neuronal maturation. These defects are rescued by GDNF expression in muscle cells in the conditions where muscular APP has been previously silenced. Expression of GDNF in muscles of amyloid precursor protein null mice corrected the aberrant synaptic morphology of NMJs. Our findings highlight for the first time that APP-dependent GDNF expression drives the process of NMJ formation, providing new insights into the link between APP gene regulatory network and physiologic functions.-Stanga, S., Zanou, N., Audouard, E., Tasiaux, B., Contino, S., Vandermeulen, G., René, F., Loeffler, J.-P., Clotman, F., Gailly, P., Dewachter, I., Octave, J.-N., Kienlen-Campard, P. APP-dependent glial cell line-derived neurotrophic factor gene expression drives neuromuscular junction formation.
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Affiliation(s)
- Serena Stanga
- Alzheimer Research Group, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Nadège Zanou
- Laboratory of Cell Physiology, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Emilie Audouard
- Laboratory of Neural Differentiation, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Bernadette Tasiaux
- Alzheimer Research Group, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Sabrina Contino
- Alzheimer Research Group, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Gaëlle Vandermeulen
- Advanced Drug Delivery and Biomaterials, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium; and
| | - Frédérique René
- Institut National de la Santé et de la Recherche Médicale, Unité 1118 Mécanismes Centraux et Périphériques de la Neurodégénérescence, Université de Strasbourg, Strasbourg Cedex, France
| | - Jean-Philippe Loeffler
- Institut National de la Santé et de la Recherche Médicale, Unité 1118 Mécanismes Centraux et Périphériques de la Neurodégénérescence, Université de Strasbourg, Strasbourg Cedex, France
| | - Frédéric Clotman
- Laboratory of Neural Differentiation, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Philippe Gailly
- Laboratory of Cell Physiology, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Ilse Dewachter
- Alzheimer Research Group, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Jean-Noël Octave
- Alzheimer Research Group, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Pascal Kienlen-Campard
- Alzheimer Research Group, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium;
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26
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Singh SK, Srivastav S, Yadav AK, Srikrishna S, Perry G. Overview of Alzheimer's Disease and Some Therapeutic Approaches Targeting Aβ by Using Several Synthetic and Herbal Compounds. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:7361613. [PMID: 27034741 PMCID: PMC4807045 DOI: 10.1155/2016/7361613] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 11/05/2015] [Indexed: 01/10/2023]
Abstract
Alzheimer's disease (AD) is a complex age-related neurodegenerative disease. In this review, we carefully detail amyloid-β metabolism and its role in AD. We also consider the various genetic animal models used to evaluate therapeutics. Finally, we consider the role of synthetic and plant-based compounds in therapeutics.
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Affiliation(s)
- Sandeep Kumar Singh
- Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, India
| | - Saurabh Srivastav
- Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, India
| | - Amarish Kumar Yadav
- Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, India
| | - Saripella Srikrishna
- Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, India
| | - George Perry
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX 78249, USA
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27
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Crenshaw E, Leung BP, Kwok CK, Sharoni M, Olson K, Sebastian NP, Ansaloni S, Schweitzer-Stenner R, Akins MR, Bevilacqua PC, Saunders AJ. Amyloid Precursor Protein Translation Is Regulated by a 3'UTR Guanine Quadruplex. PLoS One 2015; 10:e0143160. [PMID: 26618502 PMCID: PMC4664259 DOI: 10.1371/journal.pone.0143160] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 11/02/2015] [Indexed: 12/13/2022] Open
Abstract
A central event in Alzheimer’s disease is the accumulation of amyloid β (Aβ) peptides generated by the proteolytic cleavage of the amyloid precursor protein (APP). APP overexpression leads to increased Aβ generation and Alzheimer’s disease in humans and altered neuronal migration and increased long term depression in mice. Conversely, reduction of APP expression results in decreased Aβ levels in mice as well as impaired learning and memory and decreased numbers of dendritic spines. Together these findings indicate that therapeutic interventions that aim to restore APP and Aβ levels must do so within an ideal range. To better understand the effects of modulating APP levels, we explored the mechanisms regulating APP expression focusing on post-transcriptional regulation. Such regulation can be mediated by RNA regulatory elements such as guanine quadruplexes (G-quadruplexes), non-canonical structured RNA motifs that affect RNA stability and translation. Via a bioinformatics approach, we identified a candidate G-quadruplex within the APP mRNA in its 3’UTR (untranslated region) at residues 3008–3027 (NM_201414.2). This sequence exhibited characteristics of a parallel G-quadruplex structure as revealed by circular dichroism spectrophotometry. Further, as with other G-quadruplexes, the formation of this structure was dependent on the presence of potassium ions. This G-quadruplex has no apparent role in regulating transcription or mRNA stability as wild type and mutant constructs exhibited equivalent mRNA levels as determined by real time PCR. Instead, we demonstrate that this G-quadruplex negatively regulates APP protein expression using dual luciferase reporter and Western blot analysis. Taken together, our studies reveal post-transcriptional regulation by a 3’UTR G-quadruplex as a novel mechanism regulating APP expression.
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Affiliation(s)
- Ezekiel Crenshaw
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
| | - Brian P. Leung
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
- Department of Chemistry, Drexel University, Philadelphia, PA, United States of America
| | - Chun Kit Kwok
- Department of Chemistry, Pennsylvania State University, University Park, PA, United States of America
- Department of Biochemistry & Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, United States of America
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Michal Sharoni
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
| | - Kalee Olson
- Department of Chemistry, Pennsylvania State University, University Park, PA, United States of America
| | - Neeraj P. Sebastian
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
| | - Sara Ansaloni
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
| | | | - Michael R. Akins
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
- Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States of America
| | - Philip C. Bevilacqua
- Department of Chemistry, Pennsylvania State University, University Park, PA, United States of America
- Department of Biochemistry & Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, United States of America
| | - Aleister J. Saunders
- Department of Biology, Drexel University, Philadelphia, PA, United States of America
- Department of Biochemistry & Molecular Biology, Drexel University College of Medicine, Philadelphia, PA, United States of America
- Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA, United States of America
- * E-mail:
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28
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Multhaup G, Huber O, Buée L, Galas MC. Amyloid Precursor Protein (APP) Metabolites APP Intracellular Fragment (AICD), Aβ42, and Tau in Nuclear Roles. J Biol Chem 2015; 290:23515-22. [PMID: 26296890 DOI: 10.1074/jbc.r115.677211] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Amyloid precursor protein (APP) metabolites (amyloid-β (Aβ) peptides) and Tau are the main components of senile plaques and neurofibrillary tangles, the two histopathological hallmarks of Alzheimer disease. Consequently, intense research has focused upon deciphering their physiological roles to understand their altered state in Alzheimer disease pathophysiology. Recently, the impact of APP metabolites (APP intracellular fragment (AICD) and Aβ) and Tau on the nucleus has emerged as an important, new topic. Here we discuss (i) how AICD, Aβ, and Tau reach the nucleus and how AICD and Aβ control protein expression at the transcriptional level, (ii) post-translational modifications of AICD, Aβ, and Tau, and (iii) what these three molecules have in common.
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Affiliation(s)
- Gerhard Multhaup
- From the Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada,
| | - Otmar Huber
- the Institute of Biochemistry II, Jena University Hospital, Friedrich Schiller University, D-07743 Jena, Germany, and
| | - Luc Buée
- the Jean Pierre Aubert Research Centre, Alzheimer & Tauopathies, INSERM, CHU-Lille, UMR-S 1172, University of Lille, F-59000 Lille, France
| | - Marie-Christine Galas
- the Jean Pierre Aubert Research Centre, Alzheimer & Tauopathies, INSERM, CHU-Lille, UMR-S 1172, University of Lille, F-59000 Lille, France
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29
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Grimm MOW, Mett J, Stahlmann CP, Grösgen S, Haupenthal VJ, Blümel T, Hundsdörfer B, Zimmer VC, Mylonas NT, Tanila H, Müller U, Grimm HS, Hartmann T. APP intracellular domain derived from amyloidogenic β- and γ-secretase cleavage regulates neprilysin expression. Front Aging Neurosci 2015; 7:77. [PMID: 26074811 PMCID: PMC4443740 DOI: 10.3389/fnagi.2015.00077] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 04/24/2015] [Indexed: 01/30/2023] Open
Abstract
Alzheimer's disease (AD) is characterized by an accumulation of Amyloid-β (Aβ), released by sequential proteolytic processing of the amyloid precursor protein (APP) by β - and γ-secretase. Aβ peptides can aggregate, leading to toxic Aβ oligomers and amyloid plaque formation. Aβ accumulation is not only dependent on de novo synthesis but also on Aβ degradation. Neprilysin (NEP) is one of the major enzymes involved in Aβ degradation. Here we investigate the molecular mechanism of NEP regulation, which is up to now controversially discussed to be affected by APP processing itself. We found that NEP expression is highly dependent on the APP intracellular domain (AICD), released by APP processing. Mouse embryonic fibroblasts devoid of APP processing, either by the lack of the catalytically active subunit of the γ-secretase complex [presenilin (PS) 1/2] or by the lack of APP and the APP-like protein 2 (APLP2), showed a decreased NEP expression, activity and protein level. Similar results were obtained by utilizing cells lacking a functional AICD domain (APPΔCT15) or expressing mutations in the genes encoding for PS1. AICD supplementation or retransfection with an AICD encoding plasmid could rescue the down-regulation of NEP further strengthening the link between AICD and transcriptional NEP regulation, in which Fe65 acts as an important adaptor protein. Especially AICD generated by the amyloidogenic pathway seems to be more involved in the regulation of NEP expression. In line, analysis of NEP gene expression in vivo in six transgenic AD mouse models (APP and APLP2 single knock-outs, APP/APLP2 double knock-out, APP-swedish, APP-swedish/PS1Δexon9, and APPΔCT15) confirmed the results obtained in cell culture. In summary, in the present study we clearly demonstrate an AICD-dependent regulation of the Aβ-degrading enzyme NEP in vitro and in vivo and elucidate the underlying mechanisms that might be beneficial to develop new therapeutic strategies for the treatment of AD.
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Affiliation(s)
- Marcus O W Grimm
- Department of Experimental Neurology, Saarland University Homburg, Germany ; Department of Neurodegeneration and Neurobiology, Saarland University Homburg, Germany ; Deutsches Institut für DemenzPrävention, Saarland University Homburg, Germany
| | - Janine Mett
- Department of Experimental Neurology, Saarland University Homburg, Germany
| | | | - Sven Grösgen
- Department of Experimental Neurology, Saarland University Homburg, Germany
| | - Viola J Haupenthal
- Department of Experimental Neurology, Saarland University Homburg, Germany
| | - Tamara Blümel
- Department of Experimental Neurology, Saarland University Homburg, Germany
| | | | - Valerie C Zimmer
- Department of Experimental Neurology, Saarland University Homburg, Germany
| | - Nadine T Mylonas
- Department of Experimental Neurology, Saarland University Homburg, Germany
| | - Heikki Tanila
- Department of Neurobiology, A.I. Virtanen Institute, University of Eastern Finland Kuopio, Finland ; Department of Neurology, Kuopio University Hospital Kuopio, Finland
| | - Ulrike Müller
- Department of Functional Genomics, Institute for Pharmacy and Molecular Biotechnology, Heidelberg University Heidelberg, Germany
| | - Heike S Grimm
- Department of Experimental Neurology, Saarland University Homburg, Germany
| | - Tobias Hartmann
- Department of Experimental Neurology, Saarland University Homburg, Germany ; Department of Neurodegeneration and Neurobiology, Saarland University Homburg, Germany ; Deutsches Institut für DemenzPrävention, Saarland University Homburg, Germany
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Abstract
Since the original publication describing the illness in 1907, the genetic understanding of Alzheimer’s disease (AD) has advanced such that it is now clear that it is a genetically heterogeneous condition, the subtypes of which may not uniformly respond to a given intervention. It is therefore critical to characterize the clinical and preclinical stages of AD subtypes, including the rare autosomal dominant forms caused by known mutations in the PSEN1, APP, and PSEN2 genes that are being studied in the Dominantly Inherited Alzheimer Network study and its associated secondary prevention trial. Similar efforts are occurring in an extended Colombian family with a PSEN1 mutation, in APOE ε4 homozygotes, and in Down syndrome. Despite commonalities in the mechanisms producing the AD phenotype, there are also differences that reflect specific genetic origins. Treatment modalities should be chosen and trials designed with these differences in mind. Ideally, the varying pathological cascades involved in the different subtypes of AD should be defined so that both areas of overlap and of distinct differences can be taken into account. At the very least, clinical trials should determine the influence of known genetic factors in post hoc analyses.
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31
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Hage S, Stanga S, Marinangeli C, Octave JN, Dewachter I, Quetin-Leclercq J, Kienlen-Campard P. Characterization of Pterocarpus erinaceus kino extract and its gamma-secretase inhibitory properties. JOURNAL OF ETHNOPHARMACOLOGY 2015; 163:192-202. [PMID: 25639816 DOI: 10.1016/j.jep.2015.01.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 01/14/2015] [Accepted: 01/21/2015] [Indexed: 06/04/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The aqueous decoction of Pterocarpus erinaceus has been traditionally used in Benin against memory troubles. AIM OF THE STUDY New strategies are needed against Alzheimer׳s disease (AD), for, to date, AD treatment is symptomatic and consists in drugs treating the cognitive decline. An interesting target is the β-amyloid peptide (Aβ), whose accumulation and progressive deposition into amyloid plaques are key events in AD aetiology. Identifying new and more selective γ-secretase inhibitors or modulators (none of the existing has proven so far to be selective or fully efficient) appears in this respect of particular interest. We studied the activity and mechanisms of action of Pterocarpus erinaceus kino aqueous extract, after the removal of catechic tannins (KAST). METHODS AND RESULTS We tested KAST at non-toxic concentrations on cells expressing the human Amyloid Precursor Protein (APP695), as well as on primary neurons. Pterocarpus erinaceus extract was found to inhibit Aβ release in both models. We further showed that KAST inhibited γ-secretase activity in cell-free and in vitro assays, strongly suggesting that KAST is a natural γ-secretase inhibitor. Importantly, this extract did not inhibit the cleavage of Notch, another γ-secretase substrate responsible for major detrimental side effects observed with γ-secretase inhibitors. Epicatechin was further identified in KAST by HPLC-MS. CONCLUSION Pterocarpus erinaceus kino extract appears therefore as a new γ-secretase inhibitor selective towards APP processing.
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Affiliation(s)
- Salim Hage
- Université catholique de Louvain, B-1200 Brussels, Belgium; Louvain Drug Research Institute (LDRI), Université catholique de Louvain, Belgium
| | - Serena Stanga
- Université catholique de Louvain, B-1200 Brussels, Belgium; Institute of Neuroscience (IoNS), Université catholique de Louvain, Belgium
| | - Claudia Marinangeli
- Université catholique de Louvain, B-1200 Brussels, Belgium; Institute of Neuroscience (IoNS), Université catholique de Louvain, Belgium
| | - Jean-Noël Octave
- Université catholique de Louvain, B-1200 Brussels, Belgium; Institute of Neuroscience (IoNS), Université catholique de Louvain, Belgium
| | - Ilse Dewachter
- Université catholique de Louvain, B-1200 Brussels, Belgium; Institute of Neuroscience (IoNS), Université catholique de Louvain, Belgium
| | - Joëlle Quetin-Leclercq
- Université catholique de Louvain, B-1200 Brussels, Belgium; Louvain Drug Research Institute (LDRI), Université catholique de Louvain, Belgium
| | - Pascal Kienlen-Campard
- Université catholique de Louvain, B-1200 Brussels, Belgium; Institute of Neuroscience (IoNS), Université catholique de Louvain, Belgium.
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32
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Zheng C, Gu X, Zhong Z, Zhu R, Gao T, Wang F. Two memory associated genes regulated by amyloid precursor protein intracellular domain: Novel insights into the pathogenesis of learning and memory impairment in Alzheimer's disease. Neural Regen Res 2015; 7:341-6. [PMID: 25774172 PMCID: PMC4350115 DOI: 10.3969/j.issn.1673-5374.2012.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 01/22/2012] [Indexed: 12/24/2022] Open
Abstract
In this study, we employed chromatin immunoprecipitation, a useful method for studying the locations of transcription factors bound to specific DNA regions in specific cells, to investigate amyloid precursor protein intracellular domain binding sites in chromatin DNA from hippocampal neurons of rats, and to screen out five putative genes associated with the learning and memory functions. The promoter regions of the calcium/calmodulin-dependent protein kinase II alpha and glutamate receptor-2 genes were amplified by PCR from DNA products immunoprecipitated by amyloid precursor protein intracellular domain. An electrophoretic mobility shift assay and western blot analysis suggested that the promoter regions of these two genes associated with learning and memory were bound by amyloid precursor protein intracellular domain (in complex form). Our experimental findings indicate that the amyloid precursor protein intracellular domain is involved in the transcriptional regulation of learning- and memory-associated genes in hippocampal neurons. These data may provide new insights into the molecular mechanism underlying the symptoms of progressive memory loss in Alzheimer's disease.
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Affiliation(s)
- Chuandong Zheng
- Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, Guangdong Province, China
| | - Xi Gu
- Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, Guangdong Province, China
| | - Zhimei Zhong
- Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, Guangdong Province, China
| | - Rui Zhu
- Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, Guangdong Province, China
| | - Tianming Gao
- Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, Guangdong Province, China
| | - Fang Wang
- Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, Guangdong Province, China
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33
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Marinangeli C, Tasiaux B, Opsomer R, Hage S, Sodero AO, Dewachter I, Octave JN, Smith SO, Constantinescu SN, Kienlen-Campard P. Presenilin transmembrane domain 8 conserved AXXXAXXXG motifs are required for the activity of the γ-secretase complex. J Biol Chem 2015; 290:7169-84. [PMID: 25614624 DOI: 10.1074/jbc.m114.601286] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Understanding the molecular mechanisms controlling the physiological and pathological activity of γ-secretase represents a challenging task in Alzheimer disease research. The assembly and proteolytic activity of this enzyme require the correct interaction of the 19 transmembrane domains (TMDs) present in its four subunits, including presenilin (PS1 or PS2), the γ-secretase catalytic core. GXXXG and GXXXG-like motifs are critical for TMDs interactions as well as for protein folding and assembly. The GXXXG motifs on γ-secretase subunits (e.g. APH-1) or on γ-secretase substrates (e.g. APP) are known to be involved in γ-secretase assembly and in Aβ peptide production, respectively. We identified on PS1 and PS2 TMD8 two highly conserved AXXXAXXXG motifs. The presence of a mutation causing an inherited form of Alzheimer disease (familial Alzheimer disease) in the PS1 motif suggested their involvement in the physiopathological configuration of the γ-secretase complex. In this study, we targeted the role of these motifs on TMD8 of PSs, focusing on their role in PS assembly and catalytic activity. Each motif was mutated, and the impact on complex assembly, activity, and substrate docking was monitored. Different amino acid substitutions on the same motif resulted in opposite effects on γ-secretase activity, without affecting the assembly or significantly impairing the maturation of the complex. Our data suggest that AXXXAXXXG motifs in PS TMD8 are key determinants for the conformation of the mature γ-secretase complex, participating in the switch between the physiological and pathological functional conformations of the γ-secretase.
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Affiliation(s)
| | | | | | - Salim Hage
- the Louvain Drug Research Institute, and
| | | | | | | | - Steven O Smith
- the Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794-5215
| | - Stefan N Constantinescu
- the de Duve Institute and Ludwig Institute for Cancer Research, Université Catholique de Louvain, Brussels 1200, Belgium and
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34
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Abstract
Interest in the amyloid precursor protein (APP) has increased in recent years due to its involvement in Alzheimer's disease. Since its molecular cloning, significant genetic and biochemical work has focused on the role of APP in the pathogenesis of this disease. Thus far, however, these studies have failed to deliver successful therapies. This suggests that understanding the basic biology of APP and its physiological role during development might be a crucial missing link for a better comprehension of Alzheimer's disease. Here, we present an overview of some of the key studies performed in various model organisms that have revealed roles for APP at different stages of neuronal development.
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Affiliation(s)
- Maya Nicolas
- VIB Center for the Biology of Disease, VIB, 3000 Leuven, Belgium Center for Human Genetics, University of Leuven School of Medicine, 3000 Leuven, Belgium Doctoral Program in Molecular and Developmental Genetics, University of Leuven Group Biomedicine, 3000 Leuven, Belgium
| | - Bassem A Hassan
- VIB Center for the Biology of Disease, VIB, 3000 Leuven, Belgium Center for Human Genetics, University of Leuven School of Medicine, 3000 Leuven, Belgium Doctoral Program in Molecular and Developmental Genetics, University of Leuven Group Biomedicine, 3000 Leuven, Belgium
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35
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Wolfe MS. Unlocking truths of γ-secretase in Alzheimer's disease: what is the translational potential? FUTURE NEUROLOGY 2014; 9:419-429. [PMID: 26146489 DOI: 10.2217/fnl.14.35] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Considerable evidence, particularly from genetics, points to the aggregation-prone amyloid β-peptide as a pathogenic entity in Alzheimer's disease. Hence, the proteases that produce this peptide from its precursor protein have been prime targets for the development of potential therapeutics. One of these proteases, γ-secretase, has been a particular focus. Many inhibitors and modulators of this membrane-embedded protease complex have been identified, with some brought into late-stage clinical trials, where they have spectacularly failed. The reasons for these failures will be discussed, along with recent findings on the mechanism of γ-secretase and of Alzheimer-causing mutations that may suggest new strategies for targeting this enzyme.
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Affiliation(s)
- Michael S Wolfe
- Center for Neurologic Disease, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Tel.: +1 617 525 5511
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36
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Epigenetic regulations of immediate early genes expression involved in memory formation by the amyloid precursor protein of Alzheimer disease. PLoS One 2014; 9:e99467. [PMID: 24919190 PMCID: PMC4053420 DOI: 10.1371/journal.pone.0099467] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/14/2014] [Indexed: 11/19/2022] Open
Abstract
We previously demonstrated that APP epigenetically regulates Egr1 expression both in cultured neurons and in vivo. Since Egr1 is an immediate early gene involved in memory formation, we wondered whether other early genes involved in memory were regulated by APP and we studied molecular mechanisms involved. By comparing prefrontal (PF) cortex from wild type (APP+/+) and APP knockout mice (APP−/−), we observed that APP down regulates expression of four immediate early genes, Egr1, c-Fos, Bdnf and Arc. Down regulation of Egr1, c-Fos and Bdnf transcription resulted from a decreased enrichment of acetylated histone H4 on the corresponding gene promoter. Further characterization of H4 acetylation at Egr1 and c-Fos promoters revealed increased acetylation of H4K5 and H4K12 residues in APP−/− mice. Whereas APP affected Egr1 promoter activity by reducing access of the CREB transcription factor, its effect on c-Fos appeared to depend on increased recruitment of HDAC2 histone deacetylase to the gene promoter. The physiological relevance of the epigenetic regulation of Egr1 and c-Fos gene transcription by APP was further analyzed following exposure of mice to novelty. Although transcription of Egr1 and c-Fos was increased following exposure of APP+/+ mice to novelty, such an induction was not possible in APP−/− mice with a high basal level of expression of these immediate early genes. Altogether, these results demonstrate that APP-mediated regulation of c-Fos and Egr1 by different epigenetic mechanisms is needed for their induction during exposure to novelty.
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37
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Descamps O, Spilman P, Zhang Q, Libeu CP, Poksay K, Gorostiza O, Campagna J, Jagodzinska B, Bredesen DE, John V. AβPP-selective BACE inhibitors (ASBI): novel class of therapeutic agents for alzheimer's disease. J Alzheimers Dis 2014; 37:343-55. [PMID: 23948888 DOI: 10.3233/jad-130578] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A systematic approach was used to identify AβPP-selective BACE inhibitors (ASBI) and to evaluate their in vivo ability to modulate AβPP processing selectively. We identified a bioflavonoid nutritional supplement as a molecular lead that acts as an ASBI in cell models, and show that increasing brain levels of this bioflavonoid through a pro-drug approach leads to reduction of Aβ42 in an Alzheimer's disease mouse model. ASBIs represent a novel class of candidate therapeutic agents for Alzheimer's disease.
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Branca C, Sarnico I, Ruotolo R, Lanzillotta A, Viscomi AR, Benarese M, Porrini V, Lorenzini L, Calzà L, Imbimbo BP, Ottonello S, Pizzi M. Pharmacological targeting of the β-amyloid precursor protein intracellular domain. Sci Rep 2014; 4:4618. [PMID: 24714650 PMCID: PMC3980230 DOI: 10.1038/srep04618] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 03/18/2014] [Indexed: 11/09/2022] Open
Abstract
Amyloid precursor protein (APP) intracellular domain (AICD) is a product of APP processing with transcriptional modulation activity, whose overexpression causes various Alzheimer's disease (AD)-related dysfunctions. Here we report that 1-(3',4'-dichloro-2-fluoro[1,1'-biphenyl]-4-yl)-cyclopropanecarboxylic acid) (CHF5074), a compound that favorably affects neurodegeneration, neuroinflammation and memory deficit in transgenic mouse models of AD, interacts with the AICD and impairs its nuclear activity. In neuroglioma-APPswe cells, CHF5074 shifted APP cleavage from Aβ42 to the less toxic Aβ38 peptide without affecting APP-C-terminal fragment, nor APP levels. As revealed by photoaffinity labeling, CHF5074 does not interact with γ-secretase, but binds to the AICD and lowers its nuclear translocation. In vivo treatment with CHF5074 reduced AICD occupancy as well as histone H3 acetylation levels and transcriptional output of the AICD-target gene KAI1. The data provide new mechanistic insights on this compound, which is under clinical investigation for AD treatment/prevention, as well as on the contribution of the AICD to AD pathology.
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Affiliation(s)
- Caterina Branca
- 1] Department of Molecular & Translational Medicine and National Institute of Neuroscience, School of Medicine, University of Brescia, Italy [2]
| | - Ilenia Sarnico
- 1] Department of Molecular & Translational Medicine and National Institute of Neuroscience, School of Medicine, University of Brescia, Italy [2]
| | - Roberta Ruotolo
- Laboratory of Functional Genomics and Protein Engineering, Biochemistry and Molecular Biology Unit, Department of Life Sciences, University of Parma, Italy
| | - Annamaria Lanzillotta
- Department of Molecular & Translational Medicine and National Institute of Neuroscience, School of Medicine, University of Brescia, Italy
| | - Arturo Roberto Viscomi
- 1] Laboratory of Functional Genomics and Protein Engineering, Biochemistry and Molecular Biology Unit, Department of Life Sciences, University of Parma, Italy [2]
| | - Marina Benarese
- Department of Molecular & Translational Medicine and National Institute of Neuroscience, School of Medicine, University of Brescia, Italy
| | - Vanessa Porrini
- 1] Department of Molecular & Translational Medicine and National Institute of Neuroscience, School of Medicine, University of Brescia, Italy [2] IRCCS, San Camillo Hospital, Venice, Italy
| | - Luca Lorenzini
- Department of Veterinary Medicine and Health Science, University of Bologna, Italy
| | - Laura Calzà
- Department of Veterinary Medicine and Health Science, University of Bologna, Italy
| | | | - Simone Ottonello
- Laboratory of Functional Genomics and Protein Engineering, Biochemistry and Molecular Biology Unit, Department of Life Sciences, University of Parma, Italy
| | - Marina Pizzi
- 1] Department of Molecular & Translational Medicine and National Institute of Neuroscience, School of Medicine, University of Brescia, Italy [2] IRCCS, San Camillo Hospital, Venice, Italy
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Hage S, Marinangeli C, Stanga S, Octave JN, Quetin-Leclercq J, Kienlen-Campard P. Gamma-Secretase Inhibitor Activity of aPterocarpus erinaceusExtract. NEURODEGENER DIS 2014; 14:39-51. [DOI: 10.1159/000355557] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 09/10/2013] [Indexed: 11/19/2022] Open
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40
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Grimm MOW, Mett J, Stahlmann CP, Haupenthal VJ, Zimmer VC, Hartmann T. Neprilysin and Aβ Clearance: Impact of the APP Intracellular Domain in NEP Regulation and Implications in Alzheimer's Disease. Front Aging Neurosci 2013; 5:98. [PMID: 24391587 PMCID: PMC3870290 DOI: 10.3389/fnagi.2013.00098] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 12/09/2013] [Indexed: 12/18/2022] Open
Abstract
One of the characteristic hallmarks of Alzheimer's disease (AD) is an accumulation of amyloid β (Aβ) leading to plaque formation and toxic oligomeric Aβ complexes. Besides the de novo synthesis of Aβ caused by amyloidogenic processing of the amyloid precursor protein (APP), Aβ levels are also highly dependent on Aβ degradation. Several enzymes are described to cleave Aβ. In this review we focus on one of the most prominent Aβ degrading enzymes, the zinc-metalloprotease Neprilysin (NEP). In the first part of the review we discuss beside the general role of NEP in Aβ degradation the alterations of the enzyme observed during normal aging and the progression of AD. In vivo and cell culture experiments reveal that a decreased NEP level results in an increased Aβ level and vice versa. In a pathological situation like AD, it has been reported that NEP levels and activity are decreased and it has been suggested that certain polymorphisms in the NEP gene result in an increased risk for AD. Conversely, increasing NEP activity in AD mouse models revealed an improvement in some behavioral tests. Therefore it has been suggested that increasing NEP might be an interesting potential target to treat or to be protective for AD making it indispensable to understand the regulation of NEP. Interestingly, it is discussed that the APP intracellular domain (AICD), one of the cleavage products of APP processing, which has high similarities to Notch receptor processing, might be involved in the transcriptional regulation of NEP. However, the mechanisms of NEP regulation by AICD, which might be helpful to develop new therapeutic strategies, are up to now controversially discussed and summarized in the second part of this review. In addition, we review the impact of AICD not only in the transcriptional regulation of NEP but also of further genes.
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Affiliation(s)
- Marcus O W Grimm
- Experimental Neurology, Saarland University , Homburg, Saar , Germany ; Neurodegeneration and Neurobiology, Saarland University , Homburg, Saar , Germany ; Deutsches Institut für DemenzPrävention, Saarland University , Homburg, Saar , Germany
| | - Janine Mett
- Experimental Neurology, Saarland University , Homburg, Saar , Germany
| | | | | | - Valerie C Zimmer
- Experimental Neurology, Saarland University , Homburg, Saar , Germany
| | - Tobias Hartmann
- Experimental Neurology, Saarland University , Homburg, Saar , Germany ; Neurodegeneration and Neurobiology, Saarland University , Homburg, Saar , Germany ; Deutsches Institut für DemenzPrävention, Saarland University , Homburg, Saar , Germany
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41
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Hicks DA, Makova NZ, Gough M, Parkin ET, Nalivaeva NN, Turner AJ. The amyloid precursor protein represses expression of acetylcholinesterase in neuronal cell lines. J Biol Chem 2013; 288:26039-26051. [PMID: 23897820 DOI: 10.1074/jbc.m113.461269] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The toxic role of amyloid β peptides in Alzheimer's disease is well documented. Their generation is via sequential β- and γ-secretase cleavage of the membrane-bound amyloid precursor protein (APP). Other APP metabolites include the soluble ectodomains sAPPα and sAPPβ and also the amyloid precursor protein intracellular domain (AICD). In this study, we examined whether APP is involved in the regulation of acetylcholinesterase (AChE), which is a key protein of the cholinergic system and has been shown to accelerate amyloid fibril formation and increase their toxicity. Overexpression of the neuronal specific isoform, APP695, in the neuronal cell lines SN56 and SH-SY5Y substantially decreased levels of AChE mRNA, protein, and catalytic activity. Although similar decreases in mRNA levels were observed of the proline-rich anchor of AChE, PRiMA, no changes were seen in mRNA levels of the related enzyme, butyryl-cholinesterase, nor of the high-affinity choline transporter. A γ-secretase inhibitor did not affect AChE transcript levels or enzyme activity in SN56 (APP695) or SH-SY5Y (APP695) cells, showing that regulation of AChE by APP does not require the generation of AICD or amyloid β peptide. Treatment of wild-type SN56 cells with siRNA targeting APP resulted in a significant up-regulation in AChE mRNA levels. Mutagenesis studies suggest that the observed transcriptional repression of AChE is mediated by the E1 region of APP, specifically its copper-binding domain, but not the C-terminal YENTPY motif. In conclusion, AChE is regulated in two neuronal cell lines by APP in a manner independent of the generation of sAPPα, sAPPβ, and AICD.
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Affiliation(s)
- David A Hicks
- From the School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Natalia Z Makova
- From the School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Mallory Gough
- the Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, United Kingdom, and
| | - Edward T Parkin
- the Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, United Kingdom, and
| | - Natalia N Nalivaeva
- From the School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom,; the I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg 194223, Russia
| | - Anthony J Turner
- From the School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom,.
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Increasing Tip60 HAT levels rescues axonal transport defects and associated behavioral phenotypes in a Drosophila Alzheimer's disease model. J Neurosci 2013; 33:7535-47. [PMID: 23616558 DOI: 10.1523/jneurosci.3739-12.2013] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Axonal transport defects and axonopathy are prominent in early preclinical stages of Alzheimer's disease (AD), often preceding known disease-related pathology by over a year. As epigenetic transcriptional regulatory mechanisms, such as histone acetylation, are critical for neurogenesis, it is postulated that their misregulation might be linked to early pathophysiological mechanisms that contribute to AD. The histone acetyltransferase (HAT) Tip60 epigenetically regulates genes enriched for neuronal functions and is implicated in AD via its formation of a transcriptional regulatory complex with the amyloid precursor protein (APP) intracellular domain. Disruption of APP function is associated with axonal transport defects, raising the possibility that an epigenetic role for Tip60 might also be involved. Here, we examine whether Tip60 HAT activity functions in axonal transport using Drosophila CNS motor neurons as a well-characterized transport model. We show that reduction of Tip60 HAT activity in the nervous system causes axonopathy and transport defects associated with epigenetic misregulation of certain axonal transport-linked Tip60 target genes. Functional consequences of these defects are evidenced by reduced locomotion activity of the mutant Tip60 larvae, and these phenotypes can be partially rescued with certain histone deacetylase inhibitors. Finally, we demonstrate that Tip60 function in axonal transport is mediated by APP and that, remarkably, excess Tip60 exerts a neuroprotective role in APP-induced axonal transport and functional locomotion defects. Our observations highlight a novel functional interactive role between Tip60 HAT activity and APP in axonal transport and provide insight into the importance of specific HAT modulators for cognitive disorder treatment.
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Abstract
Biochemical and genetic evidence establishes a central role of the amyloid precursor protein (APP) in Alzheimer disease (AD) pathogenesis. Biochemically, deposition of the β-amyloid (Aβ) peptides produced from proteolytic processing of APP forms the defining pathological hallmark of AD; genetically, both point mutations and duplications of wild-type APP are linked to a subset of early onset of familial AD (FAD) and cerebral amyloid angiopathy. As such, the biological functions of APP and its processing products have been the subject of intense investigation, and the past 20+ years of research have met with both excitement and challenges. This article will review the current understanding of the physiological functions of APP in the context of APP family members.
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Affiliation(s)
- Ulrike C Müller
- Institute for Pharmacy and Molecular Biotechnology, University of Heidelberg, D-69120 Heidelberg, Germany.
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Shariati SAM, De Strooper B. Redundancy and divergence in the amyloid precursor protein family. FEBS Lett 2013; 587:2036-45. [PMID: 23707420 DOI: 10.1016/j.febslet.2013.05.026] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 05/08/2013] [Indexed: 11/30/2022]
Abstract
Gene duplication provides genetic material required for functional diversification. An interesting example is the amyloid precursor protein (APP) protein family. The APP gene family has experienced both expansion and contraction during evolution. The three mammalian members have been studied quite extensively in combined knock out models. The underlying assumption is that APP, amyloid precursor like protein 1 and 2 (APLP1, APLP2) are functionally redundant. This assumption is primarily supported by the similarities in biochemical processing of APP and APLPs and on the fact that the different APP genes appear to genetically interact at the level of the phenotype in combined knockout mice. However, unique features in each member of the APP family possibly contribute to specification of their function. In the current review, we discuss the evolution and the biology of the APP protein family with special attention to the distinct properties of each homologue. We propose that the functions of APP, APLP1 and APLP2 have diverged after duplication to contribute distinctly to different neuronal events. Our analysis reveals that APLP2 is significantly diverged from APP and APLP1.
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Affiliation(s)
- S Ali M Shariati
- KU Leuven, Center for Human Genetics and Leuven Institute for Neurodegenerative Diseases (LIND), 3000 Leuven, Belgium
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Nalivaeva NN, Turner AJ. The amyloid precursor protein: a biochemical enigma in brain development, function and disease. FEBS Lett 2013; 587:2046-54. [PMID: 23684647 DOI: 10.1016/j.febslet.2013.05.010] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 05/06/2013] [Accepted: 05/06/2013] [Indexed: 12/11/2022]
Abstract
For 20 years the amyloid cascade hypothesis of Alzheimer disease (AD) has placed the amyloid-β peptide (Aβ), formed from the amyloid precursor protein (APP), centre stage in the process of neurodegeneration. However, no new therapeutic agents have reached the clinic through exploitation of the hypothesis. The APP metabolites, including Aβ, generated by its proteolytic processing, have distinct physiological functions. In particular, the cleaved intracellular domain of APP (AICD) regulates expression of several genes, including APP itself, the β-secretase BACE-1 and the Aβ-degrading enzyme, neprilysin and this transcriptional regulation involves direct promoter binding of AICD. Of the three major splice isoforms of APP (APP695, APP751, APP770), APP695 is the predominant neuronal form, from which Aβ and transcriptionally-active AICD are preferentially generated by selective processing through the amyloidogenic pathway. Despite intensive research, the normal functions of the APP isoforms remain an enigma. APP plays an important role in brain development, memory and synaptic plasticity and secreted forms of APP are neuroprotective. A fuller understanding of the physiological and pathological actions of APP and its metabolic and gene regulatory network could provide new therapeutic opportunities in neurodegeneration, including AD.
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Affiliation(s)
- Natalia N Nalivaeva
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
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Rice HC, Young-Pearse TL, Selkoe DJ. Systematic evaluation of candidate ligands regulating ectodomain shedding of amyloid precursor protein. Biochemistry 2013; 52:3264-77. [PMID: 23597280 DOI: 10.1021/bi400165f] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Despite intense interest in the proteolysis of the β-Amyloid Precursor Protein (APP) in Alzheimer's disease, how the normal processing of this type I receptor-like glycoprotein is physiologically regulated remains ill-defined. In recent years, several candidate protein ligands for APP, including F-spondin, Reelin, β1 Integrin, Contactins, Lingo-1, and Pancortin, have been reported. However, a cognate ligand for APP that regulates its processing by α- or β-secretase has yet to be widely confirmed in multiple laboratories. Here, we developed new assays in an effort to confirm a role for one or more of these candidate ligands in regulating APP ectodomain shedding in a biologically relevant context. A comprehensive quantification of APPsα and APPsβ, the immediate products of secretase processing, in both non-neuronal cell lines and primary neuronal cultures expressing endogenous APP yielded no evidence that any of these published candidate ligands stimulate ectodomain shedding. Rather, Reelin, Lingo-1, and Pancortin-1 emerged as the most consistent ligands for significantly inhibiting ectodomain shedding. These findings led us to conduct further detailed analyses of the interactions of Reelin and Lingo-1 with APP.
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Affiliation(s)
- Heather C Rice
- Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School , Boston, Massachusetts 02115, United States
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Engulfment adaptor phosphotyrosine-binding-domain-containing 1 (GULP1) is a nucleocytoplasmic shuttling protein and is transactivationally active together with low-density lipoprotein receptor-related protein 1 (LRP1). Biochem J 2013; 450:333-43. [PMID: 23167255 DOI: 10.1042/bj20121100] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
APP (amyloid precursor protein) and LRP1 (low-density lipoprotein receptor-related protein 1) have been implicated in the pathogenesis of AD (Alzheimer's disease). They are functionally linked by Fe65, a PTB (phosphotyrosine-binding)-domain-containing adaptor protein that binds to intracellular NPxY-motifs of APP and LRP1, thereby influencing expression levels, cellular trafficking and processing. Additionally, Fe65 has been reported to mediate nuclear signalling in combination with intracellular domains of APP and LRP1. We have previously identified another adaptor protein, GULP1 (engulfment adaptor PTB-domain-containing 1). In the present study we characterize and compare nuclear trafficking and transactivation of GULP1 and Fe65 together with APP and LRP1 and report differential nuclear trafficking of adaptors when APP or LRP1 are co-expressed. The observed effects were additionally supported by a reporter-plasmid-based transactivation assay. The results from the present study indicate that Fe65 might have signalling properties together with APP and LRP1, whereas GULP1 only mediates LRP1 transactivation.
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Shariati SAM, Lau P, Hassan BA, Müller U, Dotti CG, De Strooper B, Gärtner A. APLP2 regulates neuronal stem cell differentiation during cortical development. J Cell Sci 2013; 126:1268-77. [PMID: 23345401 DOI: 10.1242/jcs.122440] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Expression of amyloid precursor protein (APP) and its two paralogues, APLP1 and APLP2 during brain development coincides with key cellular events such as neuronal differentiation and migration. However, genetic knockout and shRNA studies have led to contradictory conclusions about their role during embryonic brain development. To address this issue, we analysed in depth the role of APLP2 during neurogenesis by silencing APLP2 in vivo in an APP/APLP1 double knockout mouse background. We find that under these conditions cortical progenitors remain in their undifferentiated state much longer, displaying a higher number of mitotic cells. In addition, we show that neuron-specific APLP2 downregulation does not impact the speed or position of migrating excitatory cortical neurons. In summary, our data reveal that APLP2 is specifically required for proper cell cycle exit of neuronal progenitors, and thus has a distinct role in priming cortical progenitors for neuronal differentiation.
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Affiliation(s)
- S Ali M Shariati
- KU Leuven, Center for Human Genetics and Leuven Institute for Neurodegenerative Diseases, 3000 Leuven, Belgium
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Müller T, Schrötter A, Loosse C, Pfeiffer K, Theiss C, Kauth M, Meyer HE, Marcus K. A ternary complex consisting of AICD, FE65, and TIP60 down-regulates Stathmin1. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:387-94. [DOI: 10.1016/j.bbapap.2012.07.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 06/14/2012] [Accepted: 07/31/2012] [Indexed: 01/08/2023]
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Abstract
Compelling evidence from in vivo model systems within the past decade shows that the APP family of proteins is important for synaptic development and function in the central and peripheral nervous systems. The synaptic role promises to be complex and multifaceted for several reasons. The three family members have overlapping and redundant functions in mammals. They have both adhesive and signaling properties and may, in principle, act as both ligands and receptors. Moreover, they bind a multitude of synapse-specific proteins, and we predict that additional interacting protein partners will be discovered. Transgenic mice with modified or abolished expression of APP and APLPs have synaptic defects that are readily apparent. Studies of the neuromuscular junction (NMJ) in these transgenic mice have revealed molecular and functional deficits in neurotransmitter release, in organization of the postsynaptic receptors, and in coordinated intercellular development. The results summarized here from invertebrate and vertebrate systems confirm that the NMJ with its accessibility, large size, and homogeneity provides a model synapse for identifying and analyzing molecular pathways of APP actions.
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