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Żukowska J, Moss SJ, Subramanian V, Acharya KR. Molecular basis of selective amyloid-β degrading enzymes in Alzheimer's disease. FEBS J 2024; 291:2999-3029. [PMID: 37622248 DOI: 10.1111/febs.16939] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/31/2023] [Accepted: 08/22/2023] [Indexed: 08/26/2023]
Abstract
The accumulation of the small 42-residue long peptide amyloid-β (Aβ) has been proposed as a major trigger for the development of Alzheimer's disease (AD). Within the brain, the concentration of Aβ peptide is tightly controlled through production and clearance mechanisms. Substantial experimental evidence now shows that reduced levels of Aβ clearance are present in individuals living with AD. This accumulation of Aβ can lead to the formation of large aggregated amyloid plaques-one of two detectable hallmarks of the disease. Aβ-degrading enzymes (ADEs) are major players in the clearance of Aβ. Stimulating ADE activity or expression, in order to compensate for the decreased clearance in the AD phenotype, provides a promising therapeutic target. It has been reported in mice that upregulation of ADEs can reduce the levels of Aβ peptide and amyloid plaques-in some cases, this led to improved cognitive function. Among several known ADEs, neprilysin (NEP), endothelin-converting enzyme-1 (ECE-1), insulin degrading enzyme (IDE) and angiotensin-1 converting enzyme (ACE) from the zinc metalloprotease family have been identified as important. These ADEs have the capacity to digest soluble Aβ which, in turn, cannot form the toxic oligomeric species. While they are known for their amyloid degradation, they exhibit complexity through promiscuous nature and a broad range of substrates that they can degrade. This review highlights current structural and functional understanding of these key ADEs, giving some insight into the molecular interactions that leads to the hydrolysis of peptide substrates, the crucial tasks performed by them and the potential for therapeutic use in the future.
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Wareham LK, Baratta RO, Del Buono BJ, Schlumpf E, Calkins DJ. Collagen in the central nervous system: contributions to neurodegeneration and promise as a therapeutic target. Mol Neurodegener 2024; 19:11. [PMID: 38273335 PMCID: PMC10809576 DOI: 10.1186/s13024-024-00704-0] [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: 09/27/2023] [Accepted: 01/10/2024] [Indexed: 01/27/2024] Open
Abstract
The extracellular matrix is a richly bioactive composition of substrates that provides biophysical stability, facilitates intercellular signaling, and both reflects and governs the physiological status of the local microenvironment. The matrix in the central nervous system (CNS) is far from simply an inert scaffold for mechanical support, instead conducting an active role in homeostasis and providing broad capacity for adaptation and remodeling in response to stress that otherwise would challenge equilibrium between neuronal, glial, and vascular elements. A major constituent is collagen, whose characteristic triple helical structure renders mechanical and biochemical stability to enable bidirectional crosstalk between matrix and resident cells. Multiple members of the collagen superfamily are critical to neuronal maturation and circuit formation, axon guidance, and synaptogenesis in the brain. In mature tissue, collagen interacts with other fibrous proteins and glycoproteins to sustain a three-dimensional medium through which complex networks of cells can communicate. While critical for matrix scaffolding, collagen in the CNS is also highly dynamic, with multiple binding sites for partnering matrix proteins, cell-surface receptors, and other ligands. These interactions are emerging as critical mediators of CNS disease and injury, particularly regarding changes in matrix stiffness, astrocyte recruitment and reactivity, and pro-inflammatory signaling in local microenvironments. Changes in the structure and/or deposition of collagen impact cellular signaling and tissue biomechanics in the brain, which in turn can alter cellular responses including antigenicity, angiogenesis, gliosis, and recruitment of immune-related cells. These factors, each involving matrix collagen, contribute to the limited capacity for regeneration of CNS tissue. Emerging therapeutics that attempt to rebuild the matrix using peptide fragments, including collagen-enriched scaffolds and mimetics, hold great potential to promote neural repair and regeneration. Recent evidence from our group and others indicates that repairing protease-degraded collagen helices with mimetic peptides helps restore CNS tissue and promote neuronal survival in a broad spectrum of degenerative conditions. Restoration likely involves bolstering matrix stiffness to reduce the potential for astrocyte reactivity and local inflammation as well as repairing inhibitory binding sites for immune-signaling ligands. Facilitating repair rather than endogenous replacement of collagen degraded by disease or injury may represent the next frontier in developing therapies based on protection, repair, and regeneration of neurons in the central nervous system.
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Affiliation(s)
- Lauren K Wareham
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute , Vanderbilt University Medical Center, 1161 21st Avenue S, 37232, Nashville, TN, USA
| | - Robert O Baratta
- Stuart Therapeutics, Inc., 411 SE Osceola St, 34994, Stuart, FL, USA
| | - Brian J Del Buono
- Stuart Therapeutics, Inc., 411 SE Osceola St, 34994, Stuart, FL, USA
| | - Eric Schlumpf
- Stuart Therapeutics, Inc., 411 SE Osceola St, 34994, Stuart, FL, USA
| | - David J Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute , Vanderbilt University Medical Center, 1161 21st Avenue S, 37232, Nashville, TN, USA
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Ge Y, AlObaidi AS, Kuchel GA, Bartley JM, Smith PP, He W, Hu X. Dysfunctional Bladder Morphology and Functional Impairments Are Identified in the Alzheimer's Disease APPNL-G-F/NL-G-F Murine Model. J Alzheimers Dis 2024; 97:395-408. [PMID: 38160353 DOI: 10.3233/jad-230547] [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] [Indexed: 01/03/2024]
Abstract
BACKGROUND While symptoms related to lower urinary tract dysfunction (LUTD) are common in individuals with Alzheimer's disease (AD), pathophysiological links between AD and LUTD remain unclear. OBJECTIVE This study aimed to investigate whether AD neuropathology would cause autonomic dysfunction along the spinal cord-bladder axis, which could result in alterations in bladder muscle kinetics. METHODS We utilized APPNL-G-F/NL-G-F knock-in (APP KI) and APPwt/wt (wild-type) mice at two different ages, 4- and 10-month-old, to investigate how AD impacts bladder tissue function by immunohistochemistry, western blotting, and pharmacomyography. RESULTS We showed that the mucosal layer partially separated from the detrusor in 10-month-old APP KI mouse bladders. Although there was no detectable amyloid deposition in the APP KI bladder, we found amyloid plaques in APP KI lumbar spinal cord. Further immunoblot analysis revealed that tyrosine hydroxylase protein levels were significantly reduced in both 4- and 10-month-old bladder tissues, suggesting reduction of norepinephrine synthesis in APP KI mouse bladders. In contrast, the level of β2 adrenergic receptor was increased in 4-month-old but not 10-month-old APP KI bladders. In bladder strips, the adrenergic agonist isoproterenol induced increased relaxation in 4- but not 10-month-old APP KI bladders. With 10 Hz electrical field stimulation, 10-month-old APP KI bladder strips were more responsive than wild-type controls, with no differences observed in 4-month-old APP KI bladders. CONCLUSIONS APP KI mice exhibit LUTD, which is likely arising from amyloid pathology in the spinal cord, and results in maturational declines in presynaptic activity combined with compensatory postsynaptic upregulation.
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Affiliation(s)
- Yingying Ge
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Alya S AlObaidi
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
- Center on Aging, UConn Health, Farmington, CT, USA
| | | | - Jenna M Bartley
- Center on Aging, UConn Health, Farmington, CT, USA
- Department of Immunology, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Phillip P Smith
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
- Center on Aging, UConn Health, Farmington, CT, USA
| | - Wanxia He
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Xiangyou Hu
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
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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: 5] [Impact Index Per Article: 2.5] [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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Qiu Y, Sha L, Zhang X, Li G, Zhu W, Xu Q. Induction of A Disintegrin and Metalloproteinase with Thrombospondin motifs 1 by a rare variant or cognitive activities reduces hippocampal amyloid-β and consequent Alzheimer’s disease risk. Front Aging Neurosci 2022; 14:896522. [PMID: 36016856 PMCID: PMC9395645 DOI: 10.3389/fnagi.2022.896522] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 07/15/2022] [Indexed: 11/30/2022] Open
Abstract
Amyloid-β (Aβ) derived from amyloid precursor protein (APP) hydrolysis is acknowledged as the predominant hallmark of Alzheimer’s disease (AD) that especially correlates to genetics and daily activities. In 2019, meta-analysis of AD has discovered five new risk loci among which A Disintegrin and Metalloproteinase with Thrombospondin motifs 1 (ADAMTS1) has been further suggested in 2021 and 2022. To verify the association, we re-sequenced ADAMTS1 of clinical AD samples and subsequently identified a novel rare variant c.–2067A > C with watchable relevance (whereas the P-value was not significant after adjustment). Dual-luciferase assay showed that the variant sharply stimulated ADAMTS1 expression. In addition, ADAMTS1 was also clearly induced by pentylenetetrazol-ignited neuronal activity and enriched environment (EE). Inspired by the above findings, we investigated ADAMTS1’s role in APP metabolism in vitro and in vivo. Results showed that ADAMTS1 participated in APP hydrolysis and consequently decreased Aβ generation through inhibiting β-secretase-mediated cleavage. In addition, we also verified that the hippocampal amyloid load of AD mouse model was alleviated by the introduction of ADAMTS1, and thus spatial cognition was restored as well. This study revealed the contribution of ADAMTS1 to the connection of genetic and acquired factors with APP metabolism, and its potential in reducing hippocampal amyloid and consequent risk of AD.
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Affiliation(s)
- Yunjie Qiu
- State Key Laboratory of Medical Molecular Biology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing, China
| | - Longze Sha
- State Key Laboratory of Medical Molecular Biology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing, China
- Neuroscience Center, Chinese Academy of Medical Sciences, Beijing, China
| | - Xiuneng Zhang
- State Key Laboratory of Medical Molecular Biology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing, China
| | - Guanjun Li
- State Key Laboratory of Medical Molecular Biology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing, China
| | - Wanwan Zhu
- State Key Laboratory of Medical Molecular Biology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing, China
- Neuroscience Center, Chinese Academy of Medical Sciences, Beijing, China
| | - Qi Xu
- State Key Laboratory of Medical Molecular Biology, School of Basic Medicine Peking Union Medical College, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Beijing, China
- Neuroscience Center, Chinese Academy of Medical Sciences, Beijing, China
- *Correspondence: Qi Xu,
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Armbrust F, Bickenbach K, Marengo L, Pietrzik C, Becker-Pauly C. The Swedish dilemma - the almost exclusive use of APPswe-based mouse models impedes adequate evaluation of alternative β-secretases. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1869:119164. [PMID: 34699873 DOI: 10.1016/j.bbamcr.2021.119164] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/30/2021] [Accepted: 10/11/2021] [Indexed: 02/07/2023]
Abstract
Alzheimer's disease (AD) is the most common form of dementia, however incurable so far. It is widely accepted that aggregated amyloid β (Aβ) peptides play a crucial role for the pathogenesis of AD, as they cause neurotoxicity and deposit as so-called Aβ plaques in AD patient brains. Aβ peptides derive from the amyloid precursor protein (APP) upon consecutive cleavage at the β- and γ-secretase site. Hence, mutations in the APP gene are often associated with autosomal dominant inherited AD. Almost thirty years ago, two mutations at the β-secretase site were observed in two Swedish families (termed Swedish APP (APPswe) mutations), which led to early-onset AD. Consequently, APPswe was established in almost every common AD mouse model, as it contributes to early Aβ plaque formation and cognitive impairments. Analyzing these APPswe-based mouse models, the aspartyl protease BACE1 has been evolving as the prominent β-secretase responsible for Aβ release in AD and as the most important therapeutic target for AD treatment. However, with respect to β-secretase processing, the very rare occurring APPswe variant substantially differs from wild-type APP. BACE1 dominates APPswe processing resulting in the release of Aβ1-x, whereas N-terminally truncated Aβ forms are scarcely generated. However, these N-terminally truncated Aβ species such as Aβ2-x, Aβ3-x and Aβ4-x are elevated in AD patient brains and exhibit an increased potential to aggregate compared to Aβ1-x peptides. Proteases such as meprin β, cathepsin B and ADAMTS4 were identified as alternative β-secretases being capable of generating these N-terminally truncated Aβ species from wild-type APP. However, neither meprin β nor cathepsin B are capable of generating N-terminally truncated Aβ peptides from APPswe. Hence, the role of BACE1 for the Aβ formation during AD might be overrepresented through the excessive use of APPswe mouse models. In this review we critically discuss the consideration of BACE1 as the most promising therapeutic target. Shifting the focus of AD research towards alternative β secretases might unveil promising alternatives to BACE1 inhibitors constantly failing in clinical trials due to ineffectiveness and harmful side effects.
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Affiliation(s)
- Fred Armbrust
- Biochemical Institute, Unit for Degradomics of the Protease Web, University of Kiel, Kiel, Germany
| | - Kira Bickenbach
- Biochemical Institute, Unit for Degradomics of the Protease Web, University of Kiel, Kiel, Germany
| | - Liana Marengo
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Claus Pietrzik
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Christoph Becker-Pauly
- Biochemical Institute, Unit for Degradomics of the Protease Web, University of Kiel, Kiel, Germany.
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CK1δ-Derived Peptides as Novel Tools Inhibiting the Interactions between CK1δ and APP695 to Modulate the Pathogenic Metabolism of APP. Int J Mol Sci 2021; 22:ijms22126423. [PMID: 34203978 PMCID: PMC8232658 DOI: 10.3390/ijms22126423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/11/2021] [Accepted: 06/11/2021] [Indexed: 12/26/2022] Open
Abstract
Alzheimer’s disease (AD) is the major cause of dementia, and affected individuals suffer from severe cognitive, mental, and functional impairment. Histologically, AD brains are basically characterized by the presence of amyloid plaques and neurofibrillary tangles. Previous reports demonstrated that protein kinase CK1δ influences the metabolism of amyloid precursor protein (APP) by inducing the generation of amyloid-β (Aβ), finally contributing to the formation of amyloid plaques and neuronal cell death. We therefore considered CK1δ as a promising therapeutic target and suggested an innovative strategy for the treatment of AD based on peptide therapeutics specifically modulating the interaction between CK1δ and APP. Initially, CK1δ-derived peptides manipulating the interactions between CK1δ and APP695 were identified by interaction and phosphorylation analysis in vitro. Selected peptides subsequently proved their potential to penetrate cells without inducing cytotoxic effects. Finally, for at least two of the tested CK1δ-derived peptides, a reduction in Aβ levels and amyloid plaque formation could be successfully demonstrated in a complex cell culture model for AD. Consequently, the presented results provide new insights into the interactions of CK1δ and APP695 while also serving as a promising starting point for further development of novel and highly innovative pharmacological tools for the treatment of AD.
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Crivelli SM, Luo Q, Stevens JA, Giovagnoni C, van Kruining D, Bode G, den Hoedt S, Hobo B, Scheithauer AL, Walter J, Mulder MT, Exley C, Mold M, Mielke MM, De Vries HE, Wouters K, van den Hove DLA, Berkes D, Ledesma MD, Verhaagen J, Losen M, Bieberich E, Martinez-Martinez P. CERT L reduces C16 ceramide, amyloid-β levels, and inflammation in a model of Alzheimer's disease. Alzheimers Res Ther 2021; 13:45. [PMID: 33597019 PMCID: PMC7890977 DOI: 10.1186/s13195-021-00780-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 01/31/2021] [Indexed: 02/08/2023]
Abstract
BACKGROUND Dysregulation of ceramide and sphingomyelin levels have been suggested to contribute to the pathogenesis of Alzheimer's disease (AD). Ceramide transfer proteins (CERTs) are ceramide carriers which are crucial for ceramide and sphingomyelin balance in cells. Extracellular forms of CERTs co-localize with amyloid-β (Aβ) plaques in AD brains. To date, the significance of these observations for the pathophysiology of AD remains uncertain. METHODS A plasmid expressing CERTL, the long isoform of CERTs, was used to study the interaction of CERTL with amyloid precursor protein (APP) by co-immunoprecipitation and immunofluorescence in HEK cells. The recombinant CERTL protein was employed to study interaction of CERTL with amyloid-β (Aβ), Aβ aggregation process in presence of CERTL, and the resulting changes in Aβ toxicity in neuroblastoma cells. CERTL was overexpressed in neurons by adeno-associated virus (AAV) in a mouse model of familial AD (5xFAD). Ten weeks after transduction, animals were challenged with behavior tests for memory, anxiety, and locomotion. At week 12, brains were investigated for sphingolipid levels by mass spectrometry, plaques, and neuroinflammation by immunohistochemistry, gene expression, and/or immunoassay. RESULTS Here, we report that CERTL binds to APP, modifies Aβ aggregation, and reduces Aβ neurotoxicity in vitro. Furthermore, we show that intracortical injection of AAV, mediating the expression of CERTL, decreases levels of ceramide d18:1/16:0 and increases sphingomyelin levels in the brain of male 5xFAD mice. CERTL in vivo over-expression has a mild effect on animal locomotion, decreases Aβ formation, and modulates microglia by decreasing their pro-inflammatory phenotype. CONCLUSION Our results demonstrate a crucial role of CERTL in regulating ceramide levels in the brain, in amyloid plaque formation and neuroinflammation, thereby opening research avenues for therapeutic targets of AD and other neurodegenerative diseases.
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Affiliation(s)
- Simone M. Crivelli
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY USA
- Veterans Affairs Medical Center, Lexington, KY 40502 USA
| | - Qian Luo
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Jo A.A. Stevens
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Caterina Giovagnoni
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Daan van Kruining
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Gerard Bode
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Sandra den Hoedt
- Department of Internal Medicine, Laboratory Vascular Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Barbara Hobo
- Laboratory for Neuroregeneration, Netherlands institute for Neuroscience, Amsterdam, the Netherlands
| | - Anna-Lena Scheithauer
- Department of Neurology, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Jochen Walter
- Department of Neurology, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Monique T. Mulder
- Department of Internal Medicine, Laboratory Vascular Medicine, Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Christopher Exley
- The Birchall Centre, Lennard-Jones Laboratories, Keele University, Staffordshire, UK
| | - Matthew Mold
- The Birchall Centre, Lennard-Jones Laboratories, Keele University, Staffordshire, UK
| | - Michelle M. Mielke
- Division of Epidemiology, Department of Health Science Research, and Department of Neurology, Mayo Clinic Rochester, Rochester, MN USA
| | - Helga E. De Vries
- Department of Molecular Cell Biology and Immunology, Amsterdam Neuroscience, Amsterdam UMC, Amsterdam, the Netherlands
| | - Kristiaan Wouters
- Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, the Netherlands
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht, the Netherlands
| | - Daniel L. A. van den Hove
- Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany
| | - Dusan Berkes
- Department of Organic Chemistry, Slovak University of Technology, Radlinského 9, 81237 Bratislava, Slovak Republic
| | - María Dolores Ledesma
- Department of Molecular Neuropathology, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Madrid, Spain
| | - Joost Verhaagen
- Laboratory for Neuroregeneration, Netherlands institute for Neuroscience, Amsterdam, the Netherlands
| | - Mario Losen
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Erhard Bieberich
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY USA
- Veterans Affairs Medical Center, Lexington, KY 40502 USA
| | - Pilar Martinez-Martinez
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
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Guo Y, Wang Q, Chen S, Xu C. Functions of amyloid precursor protein in metabolic diseases. Metabolism 2021; 115:154454. [PMID: 33248065 DOI: 10.1016/j.metabol.2020.154454] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 11/02/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023]
Abstract
Amyloid precursor protein (APP) is a transmembrane precursor protein that is widely expressed in the central nervous system and peripheral tissues in the liver and pancreas, adipose tissue, and myotubes. APP can be cleaved by proteases in two different ways to produce a variety of short peptides, each with different physiological properties and functions. APP peptides generated by non-amyloidogenic processing can positively influence metabolism, while the peptides produced by amyloidogenic processing have the opposite effects. Here, we summarize the regulatory effects of APP and its cleavage peptides on metabolism in the central nervous system and peripheral tissues. In addition, abnormal expression and function of APP and APP-derived peptides are associated with metabolic diseases, such as type 2 diabetes, obesity, non-alcoholic fatty liver disease, and cardiovascular disease, and cancers. Pharmacological intervention of APP function or reduction of the production of peptides derived from amyloidogenic processing may be effective strategies for the prevention and treatment of Alzheimer's disease, and they may also provide new guidance for the treatment of metabolic diseases.
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Affiliation(s)
- Yanjun Guo
- Department of Gastroenterology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Qinqiu Wang
- Department of Gastroenterology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Shenghui Chen
- Department of Gastroenterology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Chengfu Xu
- Department of Gastroenterology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
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A Customized Next-Generation Sequencing-Based Panel to Identify Novel Genetic Variants in Dementing Disorders: A Pilot Study. Neural Plast 2020. [PMID: 32908482 DOI: 10.1155/2020/8078103.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Purpose The advancements in the next-generation sequencing (NGS) techniques have allowed for rapid, efficient, and cost-time-effective genetic variant detection. However, in both clinical practice and research setting, sequencing is still often limited to the use of gene panels clinically targeted on the genes underlying the disease of interest. Methods We performed a neurogenetic study through an ad hoc NGS-based custom sequencing gene panel in order to screen 16 genes in 8 patients with different types of degenerative cognitive disorders (Alzheimer's disease, mild cognitive impairment, frontotemporal dementia, and dementia associated with Parkinson's disease). The study protocol was based on previous evidence showing a high sensitivity and specificity of the technique even when the panel is limited to some hotspot exons. Results We found variants of the TREM2 and APP genes in three patients; these have been previously identified as pathogenic or likely pathogenic and, therefore, considered "disease causing." In the remaining subjects, the pathogenicity was evaluated according to the guidelines of the American College of Medical Genetics (ACMG). In one patient, the p.R205W variant in the CHMP2B gene was found to be likely pathogenic of the disease. A variant in the CSF1R and SERPINI1 genes found in two patients was classified as benign, whereas the other two (in the GRN and APP genes) were classified as likely pathogenic according to the ACMG. Conclusions Notwithstanding the preliminary value of this study, some rare genetic variants with a probable disease association were detected. Although future application of NGS-based sensors and further replication of these experimental data are needed, this approach seems to offer promising translational perspectives in the diagnosis and management of a wide range of neurodegenerative disorders.
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11
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Silva B, Niehage C, Maglione M, Hoflack B, Sigrist SJ, Wassmer T, Pavlowsky A, Preat T. Interactions between amyloid precursor protein-like (APPL) and MAGUK scaffolding proteins contribute to appetitive long-term memory in Drosophila melanogaster. J Neurogenet 2020; 34:92-105. [PMID: 31965876 DOI: 10.1080/01677063.2020.1712597] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Amyloid precursor protein (APP), the precursor of amyloid beta peptide, plays a central role in Alzheimer's disease (AD), a pathology characterized by memory decline and synaptic loss upon aging. Understanding the physiological role of APP is fundamental in deciphering the progression of AD, and several studies suggest a synaptic function via protein-protein interactions. Nevertheless, it remains unclear whether and how these interactions contribute to memory. In Drosophila, we previously showed that APP-like (APPL), the fly APP homolog, is required for aversive associative memory in the olfactory memory center, the mushroom body (MB). In the present study, we show that APPL is required for appetitive long-term memory (LTM), another form of associative memory, in a specific neuronal subpopulation of the MB, the α'/β' Kenyon cells. Using a biochemical approach, we identify the synaptic MAGUK (membrane-associated guanylate kinase) proteins X11, CASK, Dlgh2 and Dlgh4 as interactants of the APP intracellular domain (AICD). Next, we show that the Drosophila homologs CASK and Dlg are also required for appetitive LTM in the α'/β' neurons. Finally, using a double RNAi approach, we demonstrate that genetic interactions between APPL and CASK, as well as between APPL and Dlg, are critical for appetitive LTM. In summary, our results suggest that APPL contributes to associative long-term memory through its interactions with the main synaptic scaffolding proteins CASK and Dlg. This function should be conserved across species.
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Affiliation(s)
- Bryon Silva
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | | | - Marta Maglione
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | | | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | - Thomas Wassmer
- School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Alice Pavlowsky
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Thomas Preat
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
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12
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Lanza G, Calì F, Vinci M, Cosentino FII, Tripodi M, Spada RS, Cantone M, Bella R, Mattina T, Ferri R. A Customized Next-Generation Sequencing-Based Panel to Identify Novel Genetic Variants in Dementing Disorders: A Pilot Study. Neural Plast 2020; 2020:8078103. [PMID: 32908482 PMCID: PMC7450320 DOI: 10.1155/2020/8078103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 06/13/2020] [Accepted: 07/13/2020] [Indexed: 02/07/2023] Open
Abstract
PURPOSE The advancements in the next-generation sequencing (NGS) techniques have allowed for rapid, efficient, and cost-time-effective genetic variant detection. However, in both clinical practice and research setting, sequencing is still often limited to the use of gene panels clinically targeted on the genes underlying the disease of interest. METHODS We performed a neurogenetic study through an ad hoc NGS-based custom sequencing gene panel in order to screen 16 genes in 8 patients with different types of degenerative cognitive disorders (Alzheimer's disease, mild cognitive impairment, frontotemporal dementia, and dementia associated with Parkinson's disease). The study protocol was based on previous evidence showing a high sensitivity and specificity of the technique even when the panel is limited to some hotspot exons. RESULTS We found variants of the TREM2 and APP genes in three patients; these have been previously identified as pathogenic or likely pathogenic and, therefore, considered "disease causing." In the remaining subjects, the pathogenicity was evaluated according to the guidelines of the American College of Medical Genetics (ACMG). In one patient, the p.R205W variant in the CHMP2B gene was found to be likely pathogenic of the disease. A variant in the CSF1R and SERPINI1 genes found in two patients was classified as benign, whereas the other two (in the GRN and APP genes) were classified as likely pathogenic according to the ACMG. CONCLUSIONS Notwithstanding the preliminary value of this study, some rare genetic variants with a probable disease association were detected. Although future application of NGS-based sensors and further replication of these experimental data are needed, this approach seems to offer promising translational perspectives in the diagnosis and management of a wide range of neurodegenerative disorders.
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Affiliation(s)
- Giuseppe Lanza
- 1Department of Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
- 2Oasi Research Institute–IRCCS, Troina, Italy
| | | | | | | | | | | | - Mariagiovanna Cantone
- 3Department of Neurology, Sant'Elia Hospital, ASP Caltanissetta, Caltanissetta, Italy
| | - Rita Bella
- 4Department of Medical and Surgical Sciences and Advanced Technologies, University of Catania, Catania, Italy
| | - Teresa Mattina
- 5Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
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13
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Srivastava AK, Pittman JM, Zerweck J, Venkata BS, Moore PC, Sachleben JR, Meredith SC. β-Amyloid aggregation and heterogeneous nucleation. Protein Sci 2019; 28:1567-1581. [PMID: 31276610 PMCID: PMC6699094 DOI: 10.1002/pro.3674] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 06/26/2019] [Accepted: 07/03/2019] [Indexed: 01/09/2023]
Abstract
In this article, we consider the role of heterogeneous nucleation in β-amyloid aggregation. Heterogeneous nucleation is more common and occurs at lower levels of supersaturation than homogeneous nucleation. The nucleation period is also the stage at which most of the polymorphism of amyloids arises, this being one of the defining features of amyloids. We focus on several well-known heterogeneous nucleators of β-amyloid, including lipid surfaces, especially those enriched in gangliosides and cholesterol, and divalent metal ions. These two broad classes of nucleators affect β-amyloid particularly in light of the amphiphilicity of these peptides: the N-terminal region, which is largely polar and charged, contains the metal binding site, whereas the C-terminal region is aliphatic and is important in lipid binding. Notably, these two classes of nucleators can interact cooperatively, aggregation begetting greater aggregation.
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Affiliation(s)
- Atul K. Srivastava
- Department of PathologyThe University of ChicagoChicagoIllinois
- Department of Biochemistry and Molecular BiologyThe University of ChicagoChicagoIllinois
| | - Jay M. Pittman
- Department of Biochemistry and Molecular BiologyThe University of ChicagoChicagoIllinois
| | - Jonathan Zerweck
- Department of PathologyThe University of ChicagoChicagoIllinois
- Department of Biochemistry and Molecular BiologyThe University of ChicagoChicagoIllinois
| | - Bharat S. Venkata
- Department of PathologyThe University of ChicagoChicagoIllinois
- Department of Biochemistry and Molecular BiologyThe University of ChicagoChicagoIllinois
| | | | | | - Stephen C. Meredith
- Department of PathologyThe University of ChicagoChicagoIllinois
- Department of Biochemistry and Molecular BiologyThe University of ChicagoChicagoIllinois
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14
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Lu Y, Zhang S, Wang Y, Ren X, Han J. Molecular mechanisms and clinical manifestations of rare genetic disorders associated with type I collagen. Intractable Rare Dis Res 2019; 8:98-107. [PMID: 31218159 PMCID: PMC6557237 DOI: 10.5582/irdr.2019.01064] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Type I collagen is an important structural protein of bone, skin, tendon, ligament and other connective tissues. It is initially synthesized as a precursor form, procollagen, consisting of two identical pro-α1(I) and one proα2(I) chains, encoded by COL1A1 and COL1A2, respectively. The N- and C- terminal propeptides of procollagen are cleavage by N-proteinase and C-proteinase correspondingly, to form the central triple helix structure with Gly-X-Y repeat units. Mutations of COL1A1 and COL1A2 genes are associated with osteogenesis imperfecta, some types of Ehlers-Danlos syndrome, Caffey diseases, and osteogenesis imperfect/Ehlers- Danlos syndrome overlapping diseases. Clinical symptoms caused by different variations can be variable or similar, mild to lethal, and vice versa. We reviewed the relationship between clinical manifestations and type I collagen - related rare genetic disorders and their possible molecular mechanisms for different mutations and disorders.
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Affiliation(s)
- Yanqin Lu
- Key Laboratory for Biotech-Drugs of National Health Commission, Key Laboratory for Rare & Uncommon Diseases of Shandong Province, Shandong Medicinal Biotechnology Centre, Shandong First Medical University & Shandong Academy of Medical Sciences, Ji'nan, China
- School of Medicine and Life Sciences, University of Jinan-Shandong Academy of Medical Sciences, Ji'nan, China
- Address correspondence to:Dr. Yanqin Lu, Shandong First Medical University & Shandong Academy of Medical Sciences, 18877 Jingshi Road, Ji'nan 250062, China. E-mail:
| | - Shie Zhang
- Key Laboratory for Biotech-Drugs of National Health Commission, Key Laboratory for Rare & Uncommon Diseases of Shandong Province, Shandong Medicinal Biotechnology Centre, Shandong First Medical University & Shandong Academy of Medical Sciences, Ji'nan, China
- School of Medicine and Life Sciences, University of Jinan-Shandong Academy of Medical Sciences, Ji'nan, China
| | - Yanzhou Wang
- Shandong Provincial Hospital Affiliated to Shandong First Medical University, Ji'nan, China
| | - Xiuzhi Ren
- Department of Orthopaedic Surgery, The People’s Hospital of Wuqing District, Tianjin, China
| | - Jinxiang Han
- Key Laboratory for Biotech-Drugs of National Health Commission, Key Laboratory for Rare & Uncommon Diseases of Shandong Province, Shandong Medicinal Biotechnology Centre, Shandong First Medical University & Shandong Academy of Medical Sciences, Ji'nan, China
- School of Medicine and Life Sciences, University of Jinan-Shandong Academy of Medical Sciences, Ji'nan, China
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15
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Galvão F, Grokoski KC, da Silva BB, Lamers ML, Siqueira IR. The amyloid precursor protein (APP) processing as a biological link between Alzheimer's disease and cancer. Ageing Res Rev 2019; 49:83-91. [PMID: 30500566 DOI: 10.1016/j.arr.2018.11.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 11/12/2018] [Accepted: 11/26/2018] [Indexed: 01/07/2023]
Abstract
Aging is a risk factor for several illnesses, such as Alzheimer's Disease and various cancers. However, an inverse correlation between malignancies and Alzheimer's Disease has been suggested. This review addressed the potential role of non-amyloidogenic and amyloidogenic pathways of amyloid precursor protein processing as a relevant biochemical mechanism to clarify this association. Amyloidogenic and non-amyloidogenic pathways have been related to Alzheimer's Disease and certain malignancies, respectively. Several known molecules involved in APP processing, including its regulation and final products, were summarized. Among them some candidate mechanisms emerged, such as extracellular-regulated kinase (Erk) and protein kinase C (PKC). Therefore, the imbalance of APP processing may be involved with the negative correlation between cancer and Alzheimer Disease.
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16
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Schiel KA. A new etiologic model for Alzheimers Disease. Med Hypotheses 2018; 111:27-35. [DOI: 10.1016/j.mehy.2017.12.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 11/19/2017] [Accepted: 12/12/2017] [Indexed: 01/26/2023]
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17
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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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18
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Sosa LJ, Cáceres A, Dupraz S, Oksdath M, Quiroga S, Lorenzo A. The physiological role of the amyloid precursor protein as an adhesion molecule in the developing nervous system. J Neurochem 2017; 143:11-29. [PMID: 28677143 DOI: 10.1111/jnc.14122] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 06/28/2017] [Accepted: 06/29/2017] [Indexed: 12/12/2022]
Abstract
The amyloid precursor protein (APP) is a type I transmembrane glycoprotein better known for its participation in the physiopathology of Alzheimer disease as the source of the beta amyloid fragment. However, the physiological functions of the full length protein and its proteolytic fragments have remained elusive. APP was first described as a cell-surface receptor; nevertheless, increasing evidence highlighted APP as a cell adhesion molecule. In this review, we will focus on the current knowledge of the physiological role of APP as a cell adhesion molecule and its involvement in key events of neuronal development, such as migration, neurite outgrowth, growth cone pathfinding, and synaptogenesis. Finally, since APP is over-expressed in Down syndrome individuals because of the extra copy of chromosome 21, in the last section of the review, we discuss the potential contribution of APP to the neuronal and synaptic defects described in this genetic condition. Read the Editorial Highlight for this article on page 9. Cover Image for this issue: doi. 10.1111/jnc.13817.
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Affiliation(s)
- Lucas J Sosa
- Departamento de Química Biológica Ranwell Caputto, Facultad de Ciencias Químicas, CIQUIBIC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Alfredo Cáceres
- Laboratorio Neurobiología, Instituto Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina.,Instituto Universitario Ciencias Biomédicas Córdoba, Córdoba, Argentina
| | - Sebastián Dupraz
- Axonal Growth and Regeneration, German Center for Neurodegenarative Diseases, Bonn, Germany
| | - Mariana Oksdath
- Departamento de Química Biológica Ranwell Caputto, Facultad de Ciencias Químicas, CIQUIBIC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Santiago Quiroga
- Departamento de Química Biológica Ranwell Caputto, Facultad de Ciencias Químicas, CIQUIBIC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Alfredo Lorenzo
- Laboratorio de Neuropatología Experimental, Instituto de Investigación Médica Mercedes y Martín Ferreyra, INIMEC-CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
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19
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Pawlowski M, Meuth SG, Duning T. Cerebrospinal Fluid Biomarkers in Alzheimer's Disease-From Brain Starch to Bench and Bedside. Diagnostics (Basel) 2017; 7:diagnostics7030042. [PMID: 28703785 PMCID: PMC5617942 DOI: 10.3390/diagnostics7030042] [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: 05/06/2017] [Revised: 06/21/2017] [Accepted: 07/06/2017] [Indexed: 12/13/2022] Open
Abstract
Alzheimer’s disease is the most common cause of dementia. Over the last three decades, research has advanced dramatically and provided a detailed understanding of the molecular events underlying the pathogenesis of Alzheimer’s disease. In parallel, assays for the detection of biomarkers that reflect the typical Alzheimer’s disease-associated pathology have been developed and validated in myriads of clinical studies. Such biomarkers complement clinical diagnosis and improve diagnostic accuracy. The use of biomarkers will become even more important with the advent of disease-modifying therapies. Such therapies will likely be most beneficial when administered early in the disease course. Here, we summarise the development of the core Alzheimer’s disease cerebrospinal fluid biomarkers: amyloid-β and tau. We provide an overview of their role in cellular physiology and Alzheimer’s disease pathology, and embed their development as cerebrospinal fluid biomarkers into the historical context of Alzheimer’s disease research. Finally, we summarise recommendations for their use in clinical practice, and outline perspectives for novel cerebrospinal fluid candidate biomarkers.
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Affiliation(s)
- Matthias Pawlowski
- Department of Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, Münster 48149, Germany.
| | - Sven G Meuth
- Department of Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, Münster 48149, Germany.
| | - Thomas Duning
- Department of Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, Building A1, Münster 48149, Germany.
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20
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Montagna E, Dorostkar MM, Herms J. The Role of APP in Structural Spine Plasticity. Front Mol Neurosci 2017; 10:136. [PMID: 28539872 PMCID: PMC5423954 DOI: 10.3389/fnmol.2017.00136] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/21/2017] [Indexed: 11/15/2022] Open
Abstract
Amyloid precursor protein (APP) is a transmembrane protein highly expressed in neurons. The full-length protein has cell-adhesion and receptor-like properties, which play roles in synapse formation and stability. Furthermore, APP can be cleaved by several proteases into numerous fragments, many of which affect synaptic function and stability. This review article focuses on the mechanisms of APP in structural spine plasticity, which encompasses the morphological alterations at excitatory synapses. These occur as changes in the number and morphology of dendritic spines, which correspond to the postsynaptic compartment of excitatory synapses. Both overexpression and knockout (KO) of APP lead to impaired synaptic plasticity. Recent data also suggest a role of APP in the regulation of astrocytic D-serine homeostasis, which in turn regulates synaptic plasticity.
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Affiliation(s)
- Elena Montagna
- Department for Translational Brain Research, German Center for Neurodegenerative Diseases (DZNE), Ludwig-Maximilian-University MunichMunich, Germany
| | - Mario M Dorostkar
- Center for Neuropathology and Prion Research, Ludwig-Maximilian-University MunichMunich, Germany
| | - Jochen Herms
- Department for Translational Brain Research, German Center for Neurodegenerative Diseases (DZNE), Ludwig-Maximilian-University MunichMunich, Germany.,Center for Neuropathology and Prion Research, Ludwig-Maximilian-University MunichMunich, Germany.,Munich Cluster of Systems Neurology (SyNergy), Ludwig-Maximilian-University MunichMunich, Germany
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21
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Becker-Pauly C, Pietrzik CU. The Metalloprotease Meprin β Is an Alternative β-Secretase of APP. Front Mol Neurosci 2017; 9:159. [PMID: 28105004 PMCID: PMC5215381 DOI: 10.3389/fnmol.2016.00159] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 12/09/2016] [Indexed: 01/08/2023] Open
Abstract
The membrane bound metalloprotease meprin β is important for collagen fibril assembly in connective tissue formation and for the detachment of the intestinal mucus layer for proper barrier function. Recent proteomic studies revealed dozens of putative new substrates of meprin β, including the amyloid precursor protein (APP). It was shown that APP is cleaved by meprin β in distinct ways, either at the β-secretase site resulting in increased levels of Aβ peptides, or at the N-terminus releasing 11 kDa, and 20 kDa peptide fragments. The latter event was discussed to be rather neuroprotective, whereas the ectodomain shedding of APP by meprin β reminiscent to BACE-1 is in line with the amyloid hypothesis of Alzheimer's disease, promoting neurodegeneration. The N-terminal 11 kDa and 20 kDa peptide fragments represent physiological cleavage products, since they are found in human brains under different diseased or non-diseased states, whereas these fragments are completely missing in brains of meprin β knock-out animals. Meprin β is not only a sheddase of adhesion molecules, such as APP, but was additionally demonstrated to cleave within the prodomain of ADAM10. Activated ADAM10, the α-secretase of APP, is then able to shed meprin β from the cell surface thereby abolishing the β-secretase activity. All together meprin β seems to be a novel player in APP processing events, even influencing other enzymes involved in APP cleavage.
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Affiliation(s)
- Christoph Becker-Pauly
- Unit for Degradomics of the Protease Web, Institute of Biochemistry, University of Kiel Kiel, Germany
| | - Claus U Pietrzik
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz Mainz, Germany
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22
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Manocha GD, Floden AM, Rausch K, Kulas JA, McGregor BA, Rojanathammanee L, Puig KR, Puig KL, Karki S, Nichols MR, Darland DC, Porter JE, Combs CK. APP Regulates Microglial Phenotype in a Mouse Model of Alzheimer's Disease. J Neurosci 2016; 36:8471-86. [PMID: 27511018 PMCID: PMC4978805 DOI: 10.1523/jneurosci.4654-15.2016] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 05/20/2016] [Accepted: 06/24/2016] [Indexed: 01/13/2023] Open
Abstract
UNLABELLED Prior work suggests that amyloid precursor protein (APP) can function as a proinflammatory receptor on immune cells, such as monocytes and microglia. Therefore, we hypothesized that APP serves this function in microglia during Alzheimer's disease. Although fibrillar amyloid β (Aβ)-stimulated cytokine secretion from both wild-type and APP knock-out (mAPP(-/-)) microglial cultures, oligomeric Aβ was unable to stimulate increased secretion from mAPP(-/-) cells. This was consistent with an ability of oligomeric Aβ to bind APP. Similarly, intracerebroventricular infusions of oligomeric Aβ produced less microgliosis in mAPP(-/-) mice compared with wild-type mice. The mAPP(-/-) mice crossed to an APP/PS1 transgenic mouse line demonstrated reduced microgliosis and cytokine levels and improved memory compared with wild-type mice despite robust fibrillar Aβ plaque deposition. These data define a novel function for microglial APP in regulating their ability to acquire a proinflammatory phenotype during disease. SIGNIFICANCE STATEMENT A hallmark of Alzheimer's disease (AD) brains is the accumulation of amyloid β (Aβ) peptide within plaques robustly invested with reactive microglia. This supports the notion that Aβ stimulation of microglial activation is one source of brain inflammatory changes during disease. Aβ is a cleavage product of the ubiquitously expressed amyloid precursor protein (APP) and is able to self-associate into a wide variety of differently sized and structurally distinct multimers. In this study, we demonstrate both in vitro and in vivo that nonfibrillar, oligomeric forms of Aβ are able to interact with the parent APP protein to stimulate microglial activation. This provides a mechanism by which metabolism of APP results in possible autocrine or paracrine Aβ production to drive the microgliosis associated with AD brains.
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Affiliation(s)
- Gunjan D Manocha
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Angela M Floden
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Keiko Rausch
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Joshua A Kulas
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Brett A McGregor
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Lalida Rojanathammanee
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000 Thailand
| | - Kelley R Puig
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Kendra L Puig
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Sanjib Karki
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, St. Louis, Missouri 63121-4400, and
| | - Michael R Nichols
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, St. Louis, Missouri 63121-4400, and
| | - Diane C Darland
- Department of Biology, University of North Dakota, Grand Forks, North Dakota 58202
| | - James E Porter
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Colin K Combs
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203,
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23
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Yu Y, Li Y, Zhang Y. Yeast Two-Hybrid Screening for Proteins that Interact with the Extracellular Domain of Amyloid Precursor Protein. Neurosci Bull 2016; 32:171-6. [PMID: 26960425 DOI: 10.1007/s12264-016-0021-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 12/11/2015] [Indexed: 12/25/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder in which amyloid β plaques are a pathological characteristic. Little is known about the physiological functions of amyloid β precursor protein (APP). Based on its structure as a type I transmembrane protein, it has been proposed that APP might be a receptor, but so far, no ligand has been reported. In the present study, 9 proteins binding to the extracellular domain of APP were identified using a yeast two-hybrid system. After confirming the interactions in the mammalian system, mutated PLP1, members of the FLRT protein family, and KCTD16 were shown to interact with APP. These proteins have been reported to be involved in Pelizaeus-Merzbacher disease (PMD) and axon guidance. Therefore, our results shed light on the mechanisms of physiological function of APP in AD, PMD, and axon guidance.
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Affiliation(s)
- You Yu
- State Key Laboratory of Membrane Biology, College of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, 100871, China
| | - Yinan Li
- State Key Laboratory of Membrane Biology, College of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, 100871, China
| | - Yan Zhang
- State Key Laboratory of Membrane Biology, College of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, 100871, China.
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24
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APP Receptor? To Be or Not To Be. Trends Pharmacol Sci 2016; 37:390-411. [PMID: 26837733 DOI: 10.1016/j.tips.2016.01.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/07/2016] [Accepted: 01/11/2016] [Indexed: 11/22/2022]
Abstract
Amyloid precursor protein (APP) and its metabolites play a key role in Alzheimer's disease pathogenesis. The idea that APP may function as a receptor has gained momentum based on its structural similarities to type I transmembrane receptors and the identification of putative APP ligands. We review the recent experimental evidence in support of this notion and discuss how this concept is viewed in the field. Specifically, we focus on the structural and functional characteristics of APP as a cell surface receptor, and on its interaction with adaptors and signaling proteins. We also address the importance of APP function as a receptor in Alzheimer's disease etiology and discuss how this function might be potentially important for the development of novel therapeutic approaches.
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25
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Killing Me Softly: Connotations to Unfolded Protein Response and Oxidative Stress in Alzheimer's Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:1805304. [PMID: 26881014 PMCID: PMC4736771 DOI: 10.1155/2016/1805304] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 11/28/2015] [Accepted: 12/07/2015] [Indexed: 11/18/2022]
Abstract
This review is focused on the possible causes of mitochondrial dysfunction in AD, underlying molecular mechanisms of this malfunction, possible causes and known consequences of APP, Aβ, and hyperphosphorylated tau presence in mitochondria, and the contribution of altered lipid metabolism (nonsterol isoprenoids) to pathological processes leading to increased formation and accumulation of the aforementioned hallmarks of AD. Abnormal protein folding and unfolded protein response seem to be the outcomes of impaired glycosylation due to metabolic disturbances in geranylgeraniol intermediary metabolism. The origin and consecutive fate of APP, Aβ, and tau are emphasized on intracellular trafficking apparently influenced by inaccurate posttranslational modifications. We hypothesize that incorrect intracellular processing of APP determines protein translocation to mitochondria in AD. Similarly, without obvious reasons, the passage of Aβ and tau to mitochondria is observed. APP targeted to mitochondria blocks the activity of protein translocase complex resulting in poor import of proteins central to oxidative phosphorylation. Besides, APP, Aβ, and neurofibrillary tangles of tau directly or indirectly impair mitochondrial biochemistry and bioenergetics, with concomitant generation of oxidative/nitrosative stress. Limited protective mechanisms are inadequate to prevent the free radical-mediated lesions. Finally, neuronal loss is observed in AD-affected brains typically by pathologic apoptosis.
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Gonçalves R, Vasques J, Trindade P, Serfaty C, Campello-Costa P, Faria-Melibeu A. Nicotine-induced plasticity in the retinocollicular pathway: Evidence for involvement of amyloid precursor protein. Neuroscience 2016; 313:1-9. [DOI: 10.1016/j.neuroscience.2015.11.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 11/12/2015] [Accepted: 11/13/2015] [Indexed: 10/22/2022]
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van der Kant R, Goldstein LSB. Cellular functions of the amyloid precursor protein from development to dementia. Dev Cell 2015; 32:502-15. [PMID: 25710536 DOI: 10.1016/j.devcel.2015.01.022] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Amyloid precursor protein (APP) is a key player in Alzheimer's disease (AD). The Aβ fragments of APP are the major constituent of AD-associated amyloid plaques, and mutations or duplications of the gene coding for APP can cause familial AD. Here we review the roles of APP in neuronal development, signaling, intracellular transport, and other aspects of neuronal homeostasis. We suggest that APP acts as a signaling nexus that transduces information about a range of extracellular conditions, including neuronal damage, to induction of intracellular signaling events. Subtle disruptions of APP signaling functions may be major contributors to AD-causing neuronal dysfunction.
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Affiliation(s)
- Rik van der Kant
- Department of Cellular and Molecular Medicine, University of California-San Diego, La Jolla, CA 92093, USA.
| | - Lawrence S B Goldstein
- Department of Cellular and Molecular Medicine, University of California-San Diego, La Jolla, CA 92093, USA.
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Suh J, Moncaster JA, Wang L, Hafeez I, Herz J, Tanzi RE, Goldstein LE, Guénette SY. FE65 and FE65L1 amyloid precursor protein-binding protein compound null mice display adult-onset cataract and muscle weakness. FASEB J 2015; 29:2628-39. [PMID: 25757569 DOI: 10.1096/fj.14-261453] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 02/19/2015] [Indexed: 12/11/2022]
Abstract
FE65 and FE65L1 are cytoplasmic adaptor proteins that bind a variety of proteins, including the amyloid precursor protein, and that mediate the assembly of multimolecular complexes. We previously reported that FE65/FE65L1 double knockout (DKO) mice display disorganized laminin in meningeal fibroblasts and a cobblestone lissencephaly-like phenotype in the developing cortex. Here, we examined whether loss of FE65 and FE65L1 causes ocular and muscular deficits, 2 phenotypes that frequently accompany cobblestone lissencephaly. Eyes of FE65/FE65L1 DKO mice develop normally, but lens degeneration becomes apparent in young adult mice. Abnormal lens epithelial cell migration, widespread small vacuole formation, and increased laminin expression underneath lens capsules suggest impaired interaction between epithelial cells and capsular extracellular matrix in DKO lenses. Cortical cataracts develop in FE65L1 knockout (KO) mice aged 16 months or more but are absent in wild-type or FE65 KO mice. FE65 family KO mice show attenuated grip strength, and the nuclei of DKO muscle cells frequently locate in the middle of muscle fibers. These findings reveal that FE65 and FE65L1 are essential for the maintenance of lens transparency, and their loss produce phenotypes in brain, eye, and muscle that are comparable to the clinical features of congenital muscular dystrophies in humans.
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Affiliation(s)
- Jaehong Suh
- *Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, and Molecular Aging and Development Laboratory, Boston University School of Medicine, Boston, Massachusetts, USA; and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Juliet A Moncaster
- *Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, and Molecular Aging and Development Laboratory, Boston University School of Medicine, Boston, Massachusetts, USA; and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Lirong Wang
- *Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, and Molecular Aging and Development Laboratory, Boston University School of Medicine, Boston, Massachusetts, USA; and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Imran Hafeez
- *Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, and Molecular Aging and Development Laboratory, Boston University School of Medicine, Boston, Massachusetts, USA; and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Joachim Herz
- *Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, and Molecular Aging and Development Laboratory, Boston University School of Medicine, Boston, Massachusetts, USA; and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Rudolph E Tanzi
- *Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, and Molecular Aging and Development Laboratory, Boston University School of Medicine, Boston, Massachusetts, USA; and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Lee E Goldstein
- *Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, and Molecular Aging and Development Laboratory, Boston University School of Medicine, Boston, Massachusetts, USA; and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Suzanne Y Guénette
- *Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, and Molecular Aging and Development Laboratory, Boston University School of Medicine, Boston, Massachusetts, USA; and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Canobbio I, Abubaker AA, Visconte C, Torti M, Pula G. Role of amyloid peptides in vascular dysfunction and platelet dysregulation in Alzheimer's disease. Front Cell Neurosci 2015; 9:65. [PMID: 25784858 PMCID: PMC4347625 DOI: 10.3389/fncel.2015.00065] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 02/11/2015] [Indexed: 12/28/2022] Open
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative cause of dementia in the elderly. AD is accompanied by the accumulation of amyloid peptides in the brain parenchyma and in the cerebral vessels. The sporadic form of AD accounts for about 95% of all cases. It is characterized by a late onset, typically after the age of 65, with a complex and still poorly understood aetiology. Several observations point towards a central role of cerebrovascular dysfunction in the onset of sporadic AD (SAD). According to the "vascular hypothesis", AD may be initiated by vascular dysfunctions that precede and promote the neurodegenerative process. In accordance to this, AD patients show increased hemorrhagic or ischemic stroke risks. It is now clear that multiple bidirectional connections exist between AD and cerebrovascular disease, and in this new scenario, the effect of amyloid peptides on vascular cells and blood platelets appear to be central to AD. In this review, we analyze the effect of amyloid peptides on vascular function and platelet activation and its contribution to the cerebrovascular pathology associated with AD and the progression of this disease.
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Affiliation(s)
- Ilaria Canobbio
- Department of Biology and Biotechnology, Unit of Biochemistry, University of Pavia Pavia, Italy
| | - Aisha Alsheikh Abubaker
- Department of Biology and Biotechnology, Unit of Biochemistry, University of Pavia Pavia, Italy
| | - Caterina Visconte
- Department of Biology and Biotechnology, Unit of Biochemistry, University of Pavia Pavia, Italy
| | - Mauro Torti
- Department of Biology and Biotechnology, Unit of Biochemistry, University of Pavia Pavia, Italy
| | - Giordano Pula
- Department of Biology and Biotechnology, Unit of Biochemistry, University of Pavia Pavia, Italy
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Plácido A, Pereira C, Duarte A, Candeias E, Correia S, Santos R, Carvalho C, Cardoso S, Oliveira C, Moreira P. The role of endoplasmic reticulum in amyloid precursor protein processing and trafficking: Implications for Alzheimer's disease. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1444-53. [DOI: 10.1016/j.bbadis.2014.05.003] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 04/29/2014] [Accepted: 05/06/2014] [Indexed: 12/21/2022]
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Hoefgen S, Coburger I, Roeser D, Schaub Y, Dahms SO, Than ME. Heparin induced dimerization of APP is primarily mediated by E1 and regulated by its acidic domain. J Struct Biol 2014; 187:30-37. [PMID: 24859793 DOI: 10.1016/j.jsb.2014.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 05/08/2014] [Accepted: 05/14/2014] [Indexed: 11/24/2022]
Abstract
The amyloid precursor protein (APP) and its cellular processing are believed to be centrally involved in the etiology of Alzheimer's disease (AD). In addition, many physiological functions have been described for APP, including a role in cell-cell- and cell-ECM-adhesion as well as in axonal outgrowth. We show here the molecular determinants of the oligomerization/dimerization of APP, which is central for its cellular (mis)function. Using size exclusion chromatography (SEC), dynamic light scattering and SEC-coupled static light scattering we demonstrate that the dimerization of APP is energetically induced by a heparin mediated dimerization of the E1 domain, which results in a dimeric interaction of E2. We also show that the acidic domain (AcD) interferes with the dimerization of E1 and propose a model where both, cis- and trans-dimerization occur dependent on cellular localization and function.
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Affiliation(s)
- Sandra Hoefgen
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Protein Crystallography Group, Beutenbergstr. 11, 07745 Jena, Germany
| | - Ina Coburger
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Protein Crystallography Group, Beutenbergstr. 11, 07745 Jena, Germany
| | - Dirk Roeser
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Protein Crystallography Group, Beutenbergstr. 11, 07745 Jena, Germany
| | - Yvonne Schaub
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Protein Crystallography Group, Beutenbergstr. 11, 07745 Jena, Germany
| | - Sven O Dahms
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Protein Crystallography Group, Beutenbergstr. 11, 07745 Jena, Germany
| | - Manuel E Than
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Protein Crystallography Group, Beutenbergstr. 11, 07745 Jena, Germany.
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Soldano A, Hassan BA. Beyond pathology: APP, brain development and Alzheimer's disease. Curr Opin Neurobiol 2014; 27:61-7. [PMID: 24632309 DOI: 10.1016/j.conb.2014.02.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/15/2014] [Accepted: 02/06/2014] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia among the elderly. Research in the AD field has been mostly focused on the biology of the Aβ peptide but increasing evidence is shifting attention toward the physiological role of APP as key to understanding AD pathology. It is becoming apparent that APP plays a central role in the mechanisms that guarantee the accuracy and the robustness of brain wiring. In the present review we explore APP functions with focus on some of the underlying molecular mechanisms.
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Affiliation(s)
- Alessia Soldano
- VIB Center for the Biology of Disease, VIB, 3000 Leuven, Belgium; Center for Human Genetics, University of Leuven School of Medicine, 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.
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Dawkins E, Small DH. Insights into the physiological function of the β-amyloid precursor protein: beyond Alzheimer's disease. J Neurochem 2014; 129:756-69. [PMID: 24517464 PMCID: PMC4314671 DOI: 10.1111/jnc.12675] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Revised: 02/02/2014] [Accepted: 02/03/2014] [Indexed: 12/21/2022]
Abstract
The β-amyloid precursor protein (APP) has been extensively studied for its role as the precursor of the β-amyloid protein (Aβ) of Alzheimer's disease. However, the normal function of APP remains largely unknown. This article reviews studies on the structure, expression and post-translational processing of APP, as well as studies on the effects of APP in vitro and in vivo. We conclude that the published data provide strong evidence that APP has a trophic function. APP is likely to be involved in neural stem cell development, neuronal survival, neurite outgrowth and neurorepair. However, the mechanisms by which APP exerts its actions remain to be elucidated. The available evidence suggests that APP interacts both intracellularly and extracellularly to regulate various signal transduction mechanisms. This article reviews studies on the structure, expression and post-translational processing of β-amyloid precursor protein (APP), as well as studies on the effects of APP in vitro and in vivo. We conclude that the published data provide strong evidence that APP has a trophic function. APP is likely to be involved in neural stem cell development, neuronal survival, neurite outgrowth and neurorepair. However, the mechanisms by which APP exerts its actions remain to be elucidated. The available evidence suggests that APP interacts both intracellularly and extracellularly to regulate various signal transduction mechanisms.
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Affiliation(s)
- Edgar Dawkins
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia
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Sosa LJ, Postma NL, Estrada-Bernal A, Hanna M, Guo R, Busciglio J, Pfenninger KH. Dosage of amyloid precursor protein affects axonal contact guidance in Down syndrome. FASEB J 2013; 28:195-205. [PMID: 24036883 DOI: 10.1096/fj.13-232686] [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: 01/06/2023]
Abstract
Amyloid precursor protein (APP), encoded on Hsa21, functions as a cell adhesion molecule (CAM) in axonal growth cones (GCs) of the developing brain. We show here that axonal GCs of human fetal Down syndrome (DS) neurons (and of a DS mouse model) overexpress APP protein relative to euploid controls. We investigated whether DS neurons generate an abnormal, APP-dependent GC phenotype in vitro. On laminin, which binds APP and β1 integrins (Itgb1), DS neurons formed enlarged and faster-advancing GCs compared to controls. On peptide matrices that bind APP only, but not on those binding exclusively Itgb1 or L1CAM, DS GCs were significantly enlarged (2.0-fold), formed increased close adhesions (1.8-fold), and advanced faster (1.4-fold). In assays involving alternating stripes of monospecific matrices, human control GCs exhibited no preference for any of the substrates, whereas DS GCs preferred the APP-binding matrix (cross-over decreased significantly from 48.2 to 27.2%). Reducing APP expression in DS GCs with siRNA normalized most measures of the phenotype, including substrate choice. These experiments show that human DS neurons exhibit an APP-dependent, abnormal GC phenotype characterized by increased adhesion and altered contact guidance. The results suggest that APP overexpression may perturb axonal pathfinding and circuit formation in developing DS brain.
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Affiliation(s)
- Lucas J Sosa
- 3Department of Pediatrics, University of Colorado, Mailbox 8313, 12800 E. 19th Ave, Aurora, CO 80045, USA.
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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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Amyloid β precursor protein as a molecular target for amyloid β--induced neuronal degeneration in Alzheimer's disease. Neurobiol Aging 2013; 34:2525-37. [PMID: 23714735 DOI: 10.1016/j.neurobiolaging.2013.04.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/17/2013] [Accepted: 04/20/2013] [Indexed: 11/23/2022]
Abstract
A role of amyloid β (Aβ) peptide aggregation and deposition in Alzheimer's disease (AD) pathogenesis is widely accepted. Significantly, abnormalities induced by aggregated Aβ have been linked to synaptic and neuritic degeneration, consistent with the "dying-back" pattern of degeneration that characterizes neurons affected in AD. However, molecular mechanisms underlying the toxic effect of aggregated Aβ remain elusive. In the last 2 decades, a variety of aggregated Aβ species have been identified and their toxic properties demonstrated in diverse experimental systems. Concurrently, specific Aβ assemblies have been shown to interact and misregulate a growing number of molecular effectors with diverse physiological functions. Such pleiotropic effects of aggregated Aβ posit a mayor challenge for the identification of the most cardinal Aβ effectors relevant to AD pathology. In this review, we discuss recent experimental evidence implicating amyloid β precursor protein (APP) as a molecular target for toxic Aβ assemblies. Based on a significant body of pathologic observations and experimental evidence, we propose a novel pathologic feed-forward mechanism linking Aβ aggregation to abnormalities in APP processing and function, which in turn would trigger the progressive loss of neuronal connectivity observed early in AD.
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37
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Sosa LJ, Bergman J, Estrada-Bernal A, Glorioso TJ, Kittelson JM, Pfenninger KH. Amyloid precursor protein is an autonomous growth cone adhesion molecule engaged in contact guidance. PLoS One 2013; 8:e64521. [PMID: 23691241 PMCID: PMC3653867 DOI: 10.1371/journal.pone.0064521] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 04/15/2013] [Indexed: 12/22/2022] Open
Abstract
Amyloid precursor protein (APP), a transmembrane glycoprotein, is well known for its involvement in the pathogenesis of Alzheimer disease of the aging brain, but its normal function is unclear. APP is a prominent component of the adult as well as the developing brain. It is enriched in axonal growth cones (GCs) and has been implicated in cell adhesion and motility. We tested the hypothesis that APP is an extracellular matrix adhesion molecule in experiments that isolated the function of APP from that of well-established adhesion molecules. To this end we plated wild-type, APP-, or β1-integrin (Itgb1)- misexpressing mouse hippocampal neurons on matrices of either laminin, recombinant L1, or synthetic peptides binding specifically to Itgb1 s or APP. We measured GC adhesion, initial axonal outgrowth, and substrate preference on alternating matrix stripes and made the following observations: Substrates of APP-binding peptide alone sustain neurite outgrowth; APP dosage controls GC adhesion to laminin and APP-binding peptide as well as axonal outgrowth in Itgb1- independent manner; and APP directs GCs in contact guidance assays. It follows that APP is an independently operating cell adhesion molecule that affects the GC's phenotype on APP-binding matrices including laminin, and that it is likely to affect axon pathfinding in vivo.
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Affiliation(s)
- Lucas J. Sosa
- Department of Pediatrics and Colorado Intellectual and Developmental Disabilities Research Center, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Jared Bergman
- Department of Pediatrics and Colorado Intellectual and Developmental Disabilities Research Center, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Adriana Estrada-Bernal
- Department of Pediatrics and Colorado Intellectual and Developmental Disabilities Research Center, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Thomas J. Glorioso
- Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Anschutz Medical Center, Aurora, Colorado, United States of America
| | - John M. Kittelson
- Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Anschutz Medical Center, Aurora, Colorado, United States of America
| | - Karl H. Pfenninger
- Department of Pediatrics and Colorado Intellectual and Developmental Disabilities Research Center, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- * E-mail:
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Evin G, Li QX. Platelets and Alzheimer’s disease: Potential of APP as a biomarker. World J Psychiatry 2012; 2:102-13. [PMID: 24175176 PMCID: PMC3782192 DOI: 10.5498/wjp.v2.i6.102] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 07/13/2012] [Accepted: 07/23/2012] [Indexed: 02/05/2023] Open
Abstract
Platelets are the first peripheral source of amyloid precursor protein (APP). They possess the proteolytic machinery to produce Aβ and fragments similar to those produced in neurons, and thus offer an ex-vivo model to study APP processing and changes associated with Alzheimer’s disease (AD). Platelet process APP mostly through the α-secretase pathway to release soluble APP (sAPP). They produce small amounts of Aβ, predominantly Aβ40 over Aβ42. sAPP and Aβ are stored in α-granules and are released upon platelet activation by thrombin and collagen, and agents inducing platelet degranulation. A small proportion of full-length APP is present at the platelet surface and this increases by 3-fold upon platelet activation. Immunoblotting of platelet lysates detects APP as isoforms of 130 kDa and 106-110 kDa. The ratio of these of APP isoforms is significantly lower in patients with AD and mild cognitive impairment (MCI) than in healthy controls. This ratio follows a decrease that parallels cognitive decline and can predict conversion from MCI to AD. Alterations in the levels of α-secretase ADAM10 and in the enzymatic activities of α- and β-secretase observed in platelets of patients with AD are consistent with increased processing through the amyloidogenic pathway. β-APP cleaving enzyme activity is increased by 24% in platelet membranes of patients with MCI and by 17% in those with AD. Reports of changes in platelet APP expression with MCI and AD have been promising so far and merit further investigation as the search for blood biomarkers in AD, in particular at the prodromal stage, remains a priority and a challenge.
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Affiliation(s)
- Geneviève Evin
- Geneviève Evin, Qiao-Xin Li, Department of Pathology and Mental Health Research Institute, The University of Melbourne, Parkville 3010, Australia
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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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40
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Hunter S, Brayne C. Relationships between the amyloid precursor protein and its various proteolytic fragments and neuronal systems. Alzheimers Res Ther 2012; 4:10. [PMID: 22498202 PMCID: PMC3583130 DOI: 10.1186/alzrt108] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease and in its familial form is associated with mutations in the amyloid precursor protein (APP) and the presenilins (PSs). Much data regarding the interactions of APP, its proteolytic fragments and PS have been generated, expanding our understanding of the roles of these proteins in mechanisms underlying cognitive function and revealing many complex relationships with wide ranging cellular systems. In this review, we examine the multiple interactions of APP and its proteolytic fragments with other neuronal systems in terms of feedback loops and use these relationships to build a map. We highlight the complexity involved in the APP proteolytic system and discuss alternative perspectives on the roles of APP and its proteolytic fragments in dynamic processes associated with disease progression in AD. We highlight areas where data are missing and suggest potential confounding factors. We suggest that a systems biology approach enhances representations of the data and may be more useful in modelling both normal cognition and disease processes.
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Affiliation(s)
- Sally Hunter
- Institute of Public Health, University of Cambridge, Forvie site, Robinson Way, Cambridge CB2 0SR, UK
| | - Carol Brayne
- Institute of Public Health, University of Cambridge, Forvie site, Robinson Way, Cambridge CB2 0SR, UK
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41
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Schreiber A, Fischer S, Lang T. The amyloid precursor protein forms plasmalemmal clusters via its pathogenic amyloid-β domain. Biophys J 2012; 102:1411-7. [PMID: 22455924 DOI: 10.1016/j.bpj.2012.02.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 02/17/2012] [Accepted: 02/21/2012] [Indexed: 11/26/2022] Open
Abstract
The amyloid precursor protein (APP) is a large, ubiquitous integral membrane protein with a small amyloid-β (Aβ) domain. In the human brain, endosomal processing of APP produces neurotoxic Aβ-peptides, which are involved in Alzheimer's disease. Here, we show that the Aβ sequence exerts a physiological function when still present in the unprocessed APP molecule. From the extracellular site, Aβ concentrates APP molecules into plasmalemmal membrane protein clusters. Moreover, Aβ stabilization of clusters is a prerequisite for their targeting to endocytic clathrin structures. Therefore, we conclude that the Aβ domain directly mediates a central step in APP trafficking, driving its own conversion into neurotoxic peptides.
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Affiliation(s)
- Arne Schreiber
- Department of Membrane Biochemistry, Life and Medical Sciences Institute, University of Bonn, Bonn, Germany
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42
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Burgess JK, Weckmann M. Matrikines and the lungs. Pharmacol Ther 2012; 134:317-37. [PMID: 22366287 DOI: 10.1016/j.pharmthera.2012.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 02/03/2012] [Indexed: 01/09/2023]
Abstract
The extracellular matrix is a complex network of fibrous and nonfibrous molecules that not only provide structure to the lung but also interact with and regulate the behaviour of the cells which it surrounds. Recently it has been recognised that components of the extracellular matrix proteins are released, often through the action of endogenous proteases, and these fragments are termed matrikines. Matrikines have biological activities, independent of their role within the extracellular matrix structure, which may play important roles in the lung in health and disease pathology. Integrins are the primary cell surface receptors, characterised to date, which are used by the matrikines to exert their effects on cells. However, evidence is emerging for the need for co-factors and other receptors for the matrikines to exert their effects on cells. The potential for matrikines, and peptides derived from these extracellular matrix protein fragments, as therapeutic agents has recently been recognised. The natural role of these matrikines (including inhibitors of angiogenesis and possibly inflammation) make them ideal targets to mimic as therapies. A number of these peptides have been taken forward into clinical trials. The focus of this review will be to summarise our current understanding of the role, and potential for highly relevant actions, of matrikines in lung health and disease.
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Affiliation(s)
- Janette K Burgess
- Cell Biology, Woolcock Institute of Medical Research, Sydney, NSW, Australia.
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Wentzell JS, Bolkan BJ, Carmine-Simmen K, Swanson TL, Musashe DT, Kretzschmar D. Amyloid precursor proteins are protective in Drosophila models of progressive neurodegeneration. Neurobiol Dis 2012; 46:78-87. [PMID: 22266106 DOI: 10.1016/j.nbd.2011.12.047] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 12/06/2011] [Accepted: 12/31/2011] [Indexed: 12/11/2022] Open
Abstract
The processing of Amyloid Precursor Proteins (APPs) results in several fragments, including soluble N-terminal ectodomains (sAPPs) and C-terminal intracellular domains (AICD). sAPPs have been ascribed neurotrophic or neuroprotective functions in cell culture, although β-cleaved sAPPs can have deleterious effects and trigger neuronal cell death. Here we describe a neuroproprotective function of APP and fly APPL (Amyloid Precursor Protein-like) in vivo in several Drosophila mutants with progressive neurodegeneration. We show that expression of the N-terminal ectodomain is sufficient to suppress the progressive degeneration in these mutants and that the secretion of the ectodomain is required for this function. In addition, a protective effect is achieved by expressing kuzbanian (which has α-secretase activity) whereas expression of fly and human BACE aggravates the phenotypes, suggesting that the protective function is specifically mediated by the α-cleaved ectodomain. Furthermore, genetic and molecular studies suggest that the N-terminal fragments interact with full-length APPL activating a downstream signaling pathway via the AICD. Because we show protective effects in mutants that affect different genes (AMP-activated protein kinase, MAP1b, rasGAP), we propose that the protective effect is not due to a genetic interaction between APPL and these genes but a more general aspect of APP proteins. The result that APP proteins and specifically their soluble α-cleaved ectodomains can protect against progressive neurodegeneration in vivo provides support for the hypothesis that a disruption of the physiological function of APP could play a role in the pathogenesis of Alzheimer's Disease.
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Affiliation(s)
- Jill S Wentzell
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Sciences University, Portland, OR 97239, USA
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Isbert S, Wagner K, Eggert S, Schweitzer A, Multhaup G, Weggen S, Kins S, Pietrzik CU. APP dimer formation is initiated in the endoplasmic reticulum and differs between APP isoforms. Cell Mol Life Sci 2011; 69:1353-75. [PMID: 22105709 PMCID: PMC3314181 DOI: 10.1007/s00018-011-0882-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 10/25/2011] [Accepted: 10/27/2011] [Indexed: 12/30/2022]
Abstract
The amyloid precursor protein (APP) is part of a larger gene family, which has been found to form homo- or heterotypic complexes with its homologues, whereby the exact molecular mechanism and origin of dimer formation remains elusive. In order to assess the cellular location of dimerization, we have generated a cell culture model system in CHO-K1 cells, stably expressing human APP, harboring dilysine-based organelle sorting motifs [KKAA-endoplasmic reticulum (ER); KKFF-Golgi], accomplishing retention within early secretory compartments. We show that APP exists as disulfide-bonded dimers upon ER retention after it was isolated from cells, and analyzed by SDS-polyacrylamide gel electrophoresis under non-reducing conditions. In contrast, strong denaturing and reducing conditions, or deletion of the E1 domain, resulted in the disappearance of those dimers. Thus we provide first evidence that a fraction of APP can associate via intermolecular disulfide bonds, likely generated between cysteines located in the extracellular E1 domain. We particularly visualize APP dimerization itself and identified the ER as subcellular compartment of its origin using biochemical or split GFP approaches. Interestingly, we also found that minor amounts of SDS-resistant APP dimers were located to the cell surface, revealing that once generated in the oxidative environment of the ER, dimers remained stably associated during transport. In addition, we show that APP isoforms encompassing the Kunitz-type protease inhibitor (KPI) domain exhibit a strongly reduced ability to form cis-directed dimers in the ER, whereas trans-mediated cell aggregation of Drosophila Schneider S2-cells was isoform independent. Thus, suggesting that steric properties of KPI-APP might be the cause for weaker cis-interaction in the ER, compared to APP695. Finally, we provide evidence that APP/APLP1 heterointeractions are likewise initiated in the ER.
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Affiliation(s)
- Simone Isbert
- Department of Pathobiochemistry, Molecular Neurodegeneration, University Medical Center of the Johannes Gutenberg-University Mainz, Germany
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Asada-Utsugi M, Uemura K, Noda Y, Kuzuya A, Maesako M, Ando K, Kubota M, Watanabe K, Takahashi M, Kihara T, Shimohama S, Takahashi R, Berezovska O, Kinoshita A. N-cadherin enhances APP dimerization at the extracellular domain and modulates Aβ production. J Neurochem 2011; 119:354-63. [PMID: 21699541 DOI: 10.1111/j.1471-4159.2011.07364.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Sequential processing of amyloid precursor protein (APP) by β- and γ-secretase leads to the generation of amyloid-β (Aβ) peptides, which plays a central role in Alzheimer's disease pathogenesis. APP is capable of forming a homodimer through its extracellular domain as well as transmembrane GXXXG motifs. A number of reports have shown that dimerization of APP modulates Aβ production. On the other hand, we have previously reported that N-cadherin-based synaptic contact is tightly linked to Aβ production. In the present report, we investigated the effect of N-cadherin expression on APP dimerization and metabolism. Here, we demonstrate that N-cadherin expression facilitates cis-dimerization of APP. Moreover, N-cadherin expression led to increased production of Aβ as well as soluble APPβ, indicating that β-secretase-mediated cleavage of APP is enhanced. Interestingly, N-cadherin expression affected neither dimerization of C99 nor Aβ production from C99, suggesting that the effect of N-cadherin on APP metabolism is mediated through APP extracellular domain. We confirmed that N-cadherin enhances APP dimerization by a novel luciferase-complementation assay, which could be a platform for drug screening on a high-throughput basis. Taken together, our results suggest that modulation of APP dimerization state could be one of mechanisms, which links synaptic contact and Aβ production.
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Affiliation(s)
- Megumi Asada-Utsugi
- School of Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Crystal structure of amyloid precursor-like protein 1 and heparin complex suggests a dual role of heparin in E2 dimerization. Proc Natl Acad Sci U S A 2011; 108:16229-34. [PMID: 21930949 DOI: 10.1073/pnas.1103407108] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutations in amyloid precursor protein (APP) are associated with familial Alzheimer's disease. Recent development suggests that homo- and heterodimerization of APP and APP-like proteins (APLPs), which are enhanced by heparan sulfate binding, may play a role in signal transduction and cell adhesion. Despite efforts to model heparin binding based on known apo crystal structures, the mechanism of heparin-induced APP/APLP dimerization has not been established experimentally. Here we report the crystal structure of a complex between heparin and the E2 domain of APLP1, which harbors the conserved high affinity heparin binding site of the full-length molecule. Within the asymmetric E2:heparin complex, the polysaccharide is snugly bound inside a narrow groove between the two helical subdomains of one protein protomer. The nonreducing end of the sugar is positioned near the protein's 2-fold axis, making contacts with basic residues from the second protomer. The inability of the E2 dimer to accommodate two heparin molecules near its symmetry axis explains the observed 21 binding stoichiometry, which is confirmed by isothermal titration calorimetric experiment carried out in solution. We also show that, at high concentrations, heparin can destabilize E2 dimer, probably by forcing into the unoccupied binding site observed in the 21 complex. The binding model suggested by the crystal structure may facilitate the design of heparin mimetics that are capable of modulating APP dimerization in cells.
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Hashimoto H, Takeuchi T, Komatsu K, Miyazaki K, Sato M, Higashi S. Structural basis for matrix metalloproteinase-2 (MMP-2)-selective inhibitory action of β-amyloid precursor protein-derived inhibitor. J Biol Chem 2011; 286:33236-43. [PMID: 21813640 DOI: 10.1074/jbc.m111.264176] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Unlike other synthetic or physiological inhibitors for matrix metalloproteinases (MMPs), the β-amyloid precursor protein-derived inhibitory peptide (APP-IP) having an ISYGNDALMP sequence has a high selectivity toward MMP-2. Our previous study identified amino acid residues of MMP-2 essential for its selective inhibition by APP-IP and demonstrated that the N to C direction of the decapeptide inhibitor relative to the substrate-binding cleft of MMP-2 is opposite that of substrate. However, detailed interactions between the two molecules remained to be clarified. Here, we determined the crystal structure of the catalytic domain of MMP-2 in complex with APP-IP. We found that APP-IP in the complex is indeed embedded into the substrate-binding cleft of the catalytic domain in the N to C direction opposite that of substrate. With the crystal structure, it was first clarified that the aromatic side chain of Tyr(3) of the inhibitor is accommodated into the S1' pocket of the protease, and the carboxylate group of Asp(6) of APP-IP coordinates bidentately to the catalytic zinc of the enzyme. The Ala(7) to Pro(10) and Tyr(3) to Ile(1) strands of the inhibitor extend into the nonprime and the prime sides of the cleft, respectively. Therefore, the decapeptide inhibitor has long range contact with the substrate-binding cleft of the protease. This mode of interaction is probably essential for the high MMP-2 selectivity of the inhibitor because MMPs share a common architecture in the vicinity of the catalytic center, but whole structures of their substrate-binding clefts have sufficient variety for the inhibitor to distinguish MMP-2 from other MMPs.
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Affiliation(s)
- Hiroshi Hashimoto
- Department of Supramolecular Biology, Graduate School of Nanobioscience, Yokohama City University, 1-7-29, Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
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Lee S, Xue Y, Hu J, Wang Y, Liu X, Demeler B, Ha Y. The E2 domains of APP and APLP1 share a conserved mode of dimerization. Biochemistry 2011; 50:5453-64. [PMID: 21574595 DOI: 10.1021/bi101846x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Amyloid precursor protein (APP) is genetically linked to Alzheimer's disease. APP is a type I membrane protein, and its oligomeric structure is potentially important because this property may play a role in its function or affect the processing of the precursor by the secretases to generate amyloid β-peptide. Several independent studies have shown that APP can form dimers in the cell, but how it dimerizes remains controversial. At least three regions of the precursor, including a centrally located and conserved domain called E2, have been proposed to contribute to dimerization. Here we report two new crystal structures of E2, one from APP and the other from APLP1, a mammalian APP homologue. Comparison with an earlier APP structure, which was determined in a different space group, shows that the E2 domains share a conserved and antiparallel mode of dimerization. Biophysical measurements in solution show that heparin binding induces E2 dimerization. The 2.1 Å resolution electron density map also reveals phosphate ions that are bound to the protein surface. Mutational analysis shows that protein residues interacting with the phosphate ions are also involved in heparin binding. The locations of two of these residues, Arg-369 and His-433, at the dimeric interface suggest a mechanism for heparin-induced protein dimerization.
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Affiliation(s)
- Sangwon Lee
- Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut 06520, USA
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Kaden D, Munter LM, Reif B, Multhaup G. The amyloid precursor protein and its homologues: structural and functional aspects of native and pathogenic oligomerization. Eur J Cell Biol 2011; 91:234-9. [PMID: 21459473 DOI: 10.1016/j.ejcb.2011.01.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Revised: 01/24/2011] [Accepted: 01/24/2011] [Indexed: 12/20/2022] Open
Abstract
Over the last 25 years, remarkable progress has been made not only in identifying key molecules of Alzheimer's disease but also in understanding their meaning in the pathogenic state. One hallmark of Alzheimer pathology is the amyloid plaque. A major component of the extracellular deposit is the amyloid-β (Aβ) peptide which is generated from its larger precursor molecule, i.e., the amyloid precursor protein (APP) by consecutive cleavages. Processing is exerted by two enzymes, i.e., the β-secretase and the γ-secretase. We and others have found that the self-association of the amyloid peptide and the dimerization and oligomerization of these proteins is a key factor under native and pathogenic conditions. In particular, the Aβ homodimer represents a nidus for plaque formation and a well defined therapeutic target. Further, dimerization of the APP was reported to increase generation of toxic Aβ whereas heterodimerization with its homologues amyloid precursor like proteins (APLP1 and APLP2) decreased Aβ formation. This review mainly focuses on structural features of the homophilic and heterophilic interactions among APP family proteins. The proposed contact sites are described and the consequences of protein dimerization on their functions and in the pathogenesis of Alzheimer's disease are discussed.
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Affiliation(s)
- Daniela Kaden
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
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Kitazume S, Tachida Y, Kato M, Yamaguchi Y, Honda T, Hashimoto Y, Wada Y, Saito T, Iwata N, Saido T, Taniguchi N. Brain endothelial cells produce amyloid {beta} from amyloid precursor protein 770 and preferentially secrete the O-glycosylated form. J Biol Chem 2010; 285:40097-103. [PMID: 20952385 DOI: 10.1074/jbc.m110.144626] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Deposition of amyloid β (Aβ) in the brain is closely associated with Alzheimer disease (AD). Aβ is generated from amyloid precursor protein (APP) by the actions of β- and γ-secretases. In addition to Aβ deposition in the brain parenchyma, deposition of Aβ in cerebral vessel walls, termed cerebral amyloid angiopathy, is observed in more than 80% of AD individuals. The mechanism for how Aβ accumulates in blood vessels remains largely unknown. In the present study, we show that brain endothelial cells expressed APP770, a differently spliced APP mRNA isoform from neuronal APP695, and produced Aβ40 and Aβ42. Furthermore, we found that the endothelial APP770 had sialylated core 1 type O-glycans. Interestingly, Ο-glycosylated APP770 was preferentially processed by both α- and β-cleavage and secreted into the media, suggesting that O-glycosylation and APP processing involved related pathways. By immunostaining human brain sections with an anti-APP770 antibody, we found that APP770 was expressed in vascular endothelial cells. Because we were able to detect O-glycosylated sAPP770β in human cerebrospinal fluid, this unique soluble APP770β has the potential to serve as a marker for cortical dementias such as AD and vascular dementia.
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