1
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Aow J, Huang TR, Goh YT, Sun AX, Thinakaran G, Koo EH. Evidence for a clathrin-independent endocytic pathway for APP internalization in the neuronal somatodendritic compartment. Cell Rep 2023; 42:112774. [PMID: 37450368 PMCID: PMC10449584 DOI: 10.1016/j.celrep.2023.112774] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 05/08/2023] [Accepted: 06/25/2023] [Indexed: 07/18/2023] Open
Abstract
Amyloid precursor protein (APP) internalization via clathrin-/dynamin-mediated endocytosis (CME) mediated by its YENPTY motif into endosomes containing β-secretase is proposed to be critical for amyloid-beta (Aβ) production. Here, we show that somatodendritic APP internalization in primary rodent neurons is not blocked by inhibiting dynamin or mutating the YENPTY motif, in contrast to non-neuronal cell lines. These phenomena, confirmed in induced human neurons under dynamin inhibition, occur during basal conditions and chemical long-term-depression stimulus, pointing to a clathrin-independent internalization pathway for somatodendritic APP. Mutating the YENPTY motif does not alter APP recycling, degradation, or endolysosomal colocalization. However, both dynamin inhibition and the YENPTY mutant significantly decrease secreted Aβ in neurons, suggesting that internalized somatodendritic APP may not constitute a major source of Aβ. Interestingly, like APP, somatodendritic low-density lipoprotein receptor (LDLR) internalization does not require its CME motif. These results highlight intriguing differences in neuronal internalization pathways and refine our understanding of Aβ production and secretion.
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Affiliation(s)
- Jonathan Aow
- Genome Institute of Singapore, Agency for Science, Technology and Research (A(∗)STAR), 60 Biopolis Street, Genome, Singapore 138672, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
| | - Tzu-Rung Huang
- Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | - Yeek Teck Goh
- Genome Institute of Singapore, Agency for Science, Technology and Research (A(∗)STAR), 60 Biopolis Street, Genome, Singapore 138672, Singapore
| | - Alfred Xuyang Sun
- Duke-NUS Graduate Medical School, Signature Research Program in Neuroscience and Behavioural Disorders, Singapore, Singapore
| | - Gopal Thinakaran
- USF Health Byrd Alzheimer's Center and Research Institute and Department of Molecular Medicine, University of South Florida, Tampa, FL, USA
| | - Edward H Koo
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; Department of Neurosciences, University of California San Diego, San Diego, CA, USA; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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2
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Hur JY. γ-Secretase in Alzheimer's disease. Exp Mol Med 2022; 54:433-446. [PMID: 35396575 PMCID: PMC9076685 DOI: 10.1038/s12276-022-00754-8] [Citation(s) in RCA: 125] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 01/05/2022] [Accepted: 01/20/2022] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) is caused by synaptic and neuronal loss in the brain. One of the characteristic hallmarks of AD is senile plaques containing amyloid β-peptide (Aβ). Aβ is produced from amyloid precursor protein (APP) by sequential proteolytic cleavages by β-secretase and γ-secretase, and the polymerization of Aβ into amyloid plaques is thought to be a key pathogenic event in AD. Since γ-secretase mediates the final cleavage that liberates Aβ, γ-secretase has been widely studied as a potential drug target for the treatment of AD. γ-Secretase is a transmembrane protein complex containing presenilin, nicastrin, Aph-1, and Pen-2, which are sufficient for γ-secretase activity. γ-Secretase cleaves >140 substrates, including APP and Notch. Previously, γ-secretase inhibitors (GSIs) were shown to cause side effects in clinical trials due to the inhibition of Notch signaling. Therefore, more specific regulation or modulation of γ-secretase is needed. In recent years, γ-secretase modulators (GSMs) have been developed. To modulate γ-secretase and to understand its complex biology, finding the binding sites of GSIs and GSMs on γ-secretase as well as identifying transiently binding γ-secretase modulatory proteins have been of great interest. In this review, decades of findings on γ-secretase in AD are discussed.
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Affiliation(s)
- Ji-Yeun Hur
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.
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3
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Nguyen PH, Ramamoorthy A, Sahoo BR, Zheng J, Faller P, Straub JE, Dominguez L, Shea JE, Dokholyan NV, De Simone A, Ma B, Nussinov R, Najafi S, Ngo ST, Loquet A, Chiricotto M, Ganguly P, McCarty J, Li MS, Hall C, Wang Y, Miller Y, Melchionna S, Habenstein B, Timr S, Chen J, Hnath B, Strodel B, Kayed R, Lesné S, Wei G, Sterpone F, Doig AJ, Derreumaux P. Amyloid Oligomers: A Joint Experimental/Computational Perspective on Alzheimer's Disease, Parkinson's Disease, Type II Diabetes, and Amyotrophic Lateral Sclerosis. Chem Rev 2021; 121:2545-2647. [PMID: 33543942 PMCID: PMC8836097 DOI: 10.1021/acs.chemrev.0c01122] [Citation(s) in RCA: 446] [Impact Index Per Article: 111.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein misfolding and aggregation is observed in many amyloidogenic diseases affecting either the central nervous system or a variety of peripheral tissues. Structural and dynamic characterization of all species along the pathways from monomers to fibrils is challenging by experimental and computational means because they involve intrinsically disordered proteins in most diseases. Yet understanding how amyloid species become toxic is the challenge in developing a treatment for these diseases. Here we review what computer, in vitro, in vivo, and pharmacological experiments tell us about the accumulation and deposition of the oligomers of the (Aβ, tau), α-synuclein, IAPP, and superoxide dismutase 1 proteins, which have been the mainstream concept underlying Alzheimer's disease (AD), Parkinson's disease (PD), type II diabetes (T2D), and amyotrophic lateral sclerosis (ALS) research, respectively, for many years.
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Affiliation(s)
- Phuong H Nguyen
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Bikash R Sahoo
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Jie Zheng
- Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, Ohio 44325, United States
| | - Peter Faller
- Institut de Chimie, UMR 7177, CNRS-Université de Strasbourg, 4 rue Blaise Pascal, 67000 Strasbourg, France
| | - John E Straub
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Laura Dominguez
- Facultad de Química, Departamento de Fisicoquímica, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - Nikolay V Dokholyan
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
- Department of Chemistry, and Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Alfonso De Simone
- Department of Life Sciences, Imperial College London, London SW7 2AZ, U.K
- Molecular Biology, University of Naples Federico II, Naples 80138, Italy
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, Maryland 21702, United States
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Saeed Najafi
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - Son Tung Ngo
- Laboratory of Theoretical and Computational Biophysics & Faculty of Applied Sciences, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
| | - Antoine Loquet
- Institute of Chemistry & Biology of Membranes & Nanoobjects, (UMR5248 CBMN), CNRS, Université Bordeaux, Institut Européen de Chimie et Biologie, 33600 Pessac, France
| | - Mara Chiricotto
- Department of Chemical Engineering and Analytical Science, University of Manchester, Manchester M13 9PL, U.K
| | - Pritam Ganguly
- Department of Chemistry and Biochemistry, and Department of Physics, University of California, Santa Barbara, California 93106, United States
| | - James McCarty
- Chemistry Department, Western Washington University, Bellingham, Washington 98225, United States
| | - Mai Suan Li
- Institute for Computational Science and Technology, SBI Building, Quang Trung Software City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City 700000, Vietnam
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Carol Hall
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Yiming Wang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States
| | - Yifat Miller
- Department of Chemistry and The Ilse Katz Institute for Nanoscale Science & Technology, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel
| | | | - Birgit Habenstein
- Institute of Chemistry & Biology of Membranes & Nanoobjects, (UMR5248 CBMN), CNRS, Université Bordeaux, Institut Européen de Chimie et Biologie, 33600 Pessac, France
| | - Stepan Timr
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Jiaxing Chen
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
| | - Brianna Hnath
- Department of Pharmacology and Biochemistry & Molecular Biology, Penn State University College of Medicine, Hershey, Pennsylvania 17033, United States
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry (ICS-6), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rakez Kayed
- Mitchell Center for Neurodegenerative Diseases, and Departments of Neurology, Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Sylvain Lesné
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Guanghong Wei
- Department of Physics, State Key Laboratory of Surface Physics, and Key Laboratory for Computational Physical Science, Multiscale Research Institute of Complex Systems, Fudan University, Shanghai 200438, China
| | - Fabio Sterpone
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
| | - Andrew J Doig
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, U.K
| | - Philippe Derreumaux
- CNRS, UPR9080, Université de Paris, Laboratory of Theoretical Biochemistry, IBPC, Fondation Edmond de Rothschild, PSL Research University, Paris 75005, France
- Laboratory of Theoretical Chemistry, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
- Faculty of Pharmacy, Ton Duc Thang University, 33000 Ho Chi Minh City, Vietnam
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4
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Ayton S, Bush AI. β-amyloid: The known unknowns. Ageing Res Rev 2021; 65:101212. [PMID: 33188924 DOI: 10.1016/j.arr.2020.101212] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) stands out as a major disease without any form of preventative or disease modifying therapy. This is not for lack of trying. 33 phase 3 clinical trials of drugs targeting amyloid beta (Aβ) have failed to slow cognitive decline in AD. The field is at a cross-roads about whether to continue anti-Aβ therapy or more actively pursue alternative targets. With the burden of this disease to patients, families, and healthcare budgets growing yearly, the need for disease modifying AD therapies has become one of the highest priorities in all of medicine. While pathology, genetic and biochemical data offer a popular narrative for the causative role of Aβ, there are alternative explanations, and dissenting findings that, now more than ever, warrant thorough reanalysis. This review questions the major assumptions about Aβ on which therapies for AD were premised, and invites renewed interrogation into AD pathogenesis.
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Affiliation(s)
- Scott Ayton
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3052, Australia.
| | - Ashley I Bush
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3052, Australia.
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5
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Hur JY, Frost GR, Wu X, Crump C, Pan SJ, Wong E, Barros M, Li T, Nie P, Zhai Y, Wang JC, Tcw J, Guo L, McKenzie A, Ming C, Zhou X, Wang M, Sagi Y, Renton AE, Esposito BT, Kim Y, Sadleir KR, Trinh I, Rissman RA, Vassar R, Zhang B, Johnson DS, Masliah E, Greengard P, Goate A, Li YM. The innate immunity protein IFITM3 modulates γ-secretase in Alzheimer's disease. Nature 2020; 586:735-740. [PMID: 32879487 PMCID: PMC7919141 DOI: 10.1038/s41586-020-2681-2] [Citation(s) in RCA: 223] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 05/29/2020] [Indexed: 01/13/2023]
Abstract
Innate immunity is associated with Alzheimer's disease1, but the influence of immune activation on the production of amyloid-β is unknown2,3. Here we identify interferon-induced transmembrane protein 3 (IFITM3) as a γ-secretase modulatory protein, and establish a mechanism by which inflammation affects the generation of amyloid-β. Inflammatory cytokines induce the expression of IFITM3 in neurons and astrocytes, which binds to γ-secretase and upregulates its activity, thereby increasing the production of amyloid-β. The expression of IFITM3 is increased with ageing and in mouse models that express familial Alzheimer's disease genes. Furthermore, knockout of IFITM3 reduces γ-secretase activity and the formation of amyloid plaques in a transgenic mouse model (5xFAD) of early amyloid deposition. IFITM3 protein is upregulated in tissue samples from a subset of patients with late-onset Alzheimer's disease that exhibit higher γ-secretase activity. The amount of IFITM3 in the γ-secretase complex has a strong and positive correlation with γ-secretase activity in samples from patients with late-onset Alzheimer's disease. These findings reveal a mechanism in which γ-secretase is modulated by neuroinflammation via IFITM3 and the risk of Alzheimer's disease is thereby increased.
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Affiliation(s)
- Ji-Yeun Hur
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Georgia R Frost
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Program of Neurosciences, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
| | - Xianzhong Wu
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Christina Crump
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Program of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
| | - Si Jia Pan
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Eitan Wong
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Marilia Barros
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Thomas Li
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Program of Neurosciences, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
| | - Pengju Nie
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Program of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
| | - Yujia Zhai
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jen Chyong Wang
- Ronald M. Loeb Center for Alzheimer's Disease, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Julia Tcw
- Ronald M. Loeb Center for Alzheimer's Disease, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Lei Guo
- Department of Genetics and Genomic Sciences, Mount Sinai Center for Transformative Disease Modeling, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Andrew McKenzie
- Department of Genetics and Genomic Sciences, Mount Sinai Center for Transformative Disease Modeling, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Chen Ming
- Department of Genetics and Genomic Sciences, Mount Sinai Center for Transformative Disease Modeling, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Xianxiao Zhou
- Department of Genetics and Genomic Sciences, Mount Sinai Center for Transformative Disease Modeling, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Minghui Wang
- Department of Genetics and Genomic Sciences, Mount Sinai Center for Transformative Disease Modeling, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yotam Sagi
- Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, NY, USA
| | - Alan E Renton
- Ronald M. Loeb Center for Alzheimer's Disease, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Bianca T Esposito
- Ronald M. Loeb Center for Alzheimer's Disease, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yong Kim
- Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, NY, USA
| | | | - Ivy Trinh
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Robert A Rissman
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Robert Vassar
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Bin Zhang
- Department of Genetics and Genomic Sciences, Mount Sinai Center for Transformative Disease Modeling, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Eliezer Masliah
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Paul Greengard
- Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, NY, USA
| | - Alison Goate
- Ronald M. Loeb Center for Alzheimer's Disease, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Genetics and Genomic Sciences, Mount Sinai Center for Transformative Disease Modeling, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yue-Ming Li
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Program of Neurosciences, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA.
- Program of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA.
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6
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Gireud-Goss M, Reyes S, Tewari R, Patrizz A, Howe MD, Kofler J, Waxham MN, McCullough LD, Bean AJ. The ubiquitin ligase UBE4B regulates amyloid precursor protein ubiquitination, endosomal trafficking, and amyloid β42 generation and secretion. Mol Cell Neurosci 2020; 108:103542. [PMID: 32841720 DOI: 10.1016/j.mcn.2020.103542] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 01/01/2023] Open
Abstract
The extracellular accumulation of amyloid β (Aβ) fragments of amyloid precursor protein (APP) in brain parenchyma is a pathological hallmark of Alzheimer's disease (AD). APP can be cleaved into Aβ on late endosomes/multivesicular bodies (MVBs). E3 ubiquitin ligases have been linked to Aβ production, but specific E3 ligases associated with APP ubiquitination that may affect targeting of APP to endosomes have not yet been described. Using cultured cortical neurons isolated from rat pups, we reconstituted APP movement into the internal vesicles (ILVs) of MVBs. Loss of endosomal sorting complexes required for transport (ESCRT) components inhibited APP movement into ILVs and increased endosomal Aβ42 generation, implying a requirement for APP ubiquitination. We identified an ESCRT-binding and APP-interacting endosomal E3 ubiquitin ligase, ubiquitination factor E4B (UBE4B) that regulates APP ubiquitination. Depleting UBE4B in neurons inhibited APP ubiquitination and internalization into MVBs, resulting in increased endosomal Aβ42 levels and increased neuronal secretion of Aβ42. When we examined AD brains, we found levels of the UBE4B-interacting ESCRT component, hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs), were significantly decreased in AD brains. These data suggest that ESCRT components critical for membrane protein sorting in the endocytic pathway are altered in AD. These results indicate that the molecular machinery underlying endosomal trafficking of APP, including the ubiquitin ligase UBE4B, regulates Aβ levels and may play an essential role in AD progression.
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Affiliation(s)
- Monica Gireud-Goss
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America; The M.D. Anderson/UTHealth Graduate School of Biomedical Sciences at Houston, United States of America; Department of Neurology McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America
| | - Sahily Reyes
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America; The M.D. Anderson/UTHealth Graduate School of Biomedical Sciences at Houston, United States of America
| | - Ritika Tewari
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America
| | - Anthony Patrizz
- The M.D. Anderson/UTHealth Graduate School of Biomedical Sciences at Houston, United States of America; Department of Neurology McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America
| | - Matthew D Howe
- The M.D. Anderson/UTHealth Graduate School of Biomedical Sciences at Houston, United States of America; Department of Neurology McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America
| | - Julia Kofler
- Division of Neuropathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, United States of America
| | - M Neal Waxham
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America
| | - Louise D McCullough
- The M.D. Anderson/UTHealth Graduate School of Biomedical Sciences at Houston, United States of America; Department of Neurology McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America
| | - Andrew J Bean
- Department of Neurobiology and Anatomy, McGovern Medical School at The University of Texas Health Science Center at Houston, United States of America; The M.D. Anderson/UTHealth Graduate School of Biomedical Sciences at Houston, United States of America; Department of Pediatrics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, United States of America; Rush University Graduate College, Chicago, IL 60612, United States of America.
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7
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Ahmad F, Liu P. Synaptosome as a tool in Alzheimer's disease research. Brain Res 2020; 1746:147009. [PMID: 32659233 DOI: 10.1016/j.brainres.2020.147009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/21/2020] [Accepted: 07/04/2020] [Indexed: 12/29/2022]
Abstract
Synapse dysfunction is an integral feature of Alzheimer's disease (AD) pathophysiology. In fact, prodromal manifestation of structural and functional deficits in synapses much prior to appearance of overt pathological hallmarks of the disease indicates that AD might be considered as a degenerative disorder of the synapses. Several research instruments and techniques have allowed us to study synaptic function and plasticity and their alterations in pathological conditions, such as AD. One such tool is the biochemically isolated preparations of detached and resealed synaptic terminals, the "synaptosomes". Because of the preservation of many of the physiological processes such as metabolic and enzymatic activities, synaptosomes have proved to be an indispensable ex vivo model system to study synapse physiology both when isolated from fresh or cryopreserved tissues, and from animal or human post-mortem tissues. This model system has been tremendously successful in the case of post-mortem tissues because of their accessibility relative to acute brain slices or cultures. The current review details the use of synaptosomes in AD research and its potential as a valuable tool in furthering our understanding of the pathogenesis and in devising and testing of therapeutic strategies for the disease.
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Affiliation(s)
- Faraz Ahmad
- Department of Anatomy, School of Biomedical Sciences, Brain Research New Zealand, University of Otago, Dunedin, New Zealand.
| | - Ping Liu
- Department of Anatomy, School of Biomedical Sciences, Brain Research New Zealand, University of Otago, Dunedin, New Zealand
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8
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Barthelson K, Newman M, Lardelli M. Sorting Out the Role of the Sortilin-Related Receptor 1 in Alzheimer's Disease. J Alzheimers Dis Rep 2020; 4:123-140. [PMID: 32587946 PMCID: PMC7306921 DOI: 10.3233/adr-200177] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2020] [Indexed: 12/18/2022] Open
Abstract
Sortilin-related receptor 1 (SORL1) encodes a large, multi-domain containing, membrane-bound receptor involved in endosomal sorting of proteins between the trans-Golgi network, endosomes and the plasma membrane. It is genetically associated with Alzheimer's disease (AD), the most common form of dementia. SORL1 is a unique gene in AD, as it appears to show strong associations with the common, late-onset, sporadic form of AD and the rare, early-onset familial form of AD. Here, we review the genetics of SORL1 in AD and discuss potential roles it could play in AD pathogenesis.
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Affiliation(s)
- Karissa Barthelson
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Morgan Newman
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Michael Lardelli
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
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9
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Mouchlis VD, Melagraki G, Zacharia LC, Afantitis A. Computer-Aided Drug Design of β-Secretase, γ-Secretase and Anti-Tau Inhibitors for the Discovery of Novel Alzheimer's Therapeutics. Int J Mol Sci 2020; 21:E703. [PMID: 31973122 PMCID: PMC7038192 DOI: 10.3390/ijms21030703] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/15/2020] [Accepted: 01/17/2020] [Indexed: 12/14/2022] Open
Abstract
Aging-associated neurodegenerative diseases, which are characterized by progressive neuronal death and synapses loss in human brain, are rapidly growing affecting millions of people globally. Alzheimer's is the most common neurodegenerative disease and it can be caused by genetic and environmental risk factors. This review describes the amyloid-β and Tau hypotheses leading to amyloid plaques and neurofibrillary tangles, respectively which are the predominant pathways for the development of anti-Alzheimer's small molecule inhibitors. The function and structure of the druggable targets of these two pathways including β-secretase, γ-secretase, and Tau are discussed in this review article. Computer-Aided Drug Design including computational structure-based design and ligand-based design have been employed successfully to develop inhibitors for biomolecular targets involved in Alzheimer's. The application of computational molecular modeling for the discovery of small molecule inhibitors and modulators for β-secretase and γ-secretase is summarized. Examples of computational approaches employed for the development of anti-amyloid aggregation and anti-Tau phosphorylation, proteolysis and aggregation inhibitors are also reported.
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Affiliation(s)
| | - Georgia Melagraki
- Division of Physical Sciences & Applications, Hellenic Military Academy, Vari 16672, Greece;
| | - Lefteris C. Zacharia
- Department of Life and Health Sciences, University of Nicosia, Nicosia 1700, Cyprus;
| | - Antreas Afantitis
- Department of ChemoInformatics, NovaMechanics Ltd., Nicosia 1046, Cyprus
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10
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Lee YJ, Ch'ng TH. RIP at the Synapse and the Role of Intracellular Domains in Neurons. Neuromolecular Med 2019; 22:1-24. [PMID: 31346933 DOI: 10.1007/s12017-019-08556-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/12/2019] [Indexed: 12/18/2022]
Abstract
Regulated intramembrane proteolysis (RIP) occurs in a cell when transmembrane proteins are cleaved by intramembrane proteases such as secretases to generate soluble protein fragments in the extracellular environment and the cytosol. In the cytosol, these soluble intracellular domains (ICDs) have local functions near the site of cleavage or in many cases, translocate to the nucleus to modulate gene expression. While the mechanism of RIP is relatively well studied, the fate and function of ICDs for most substrate proteins remain poorly characterized. In neurons, RIP occurs in various subcellular compartments including at the synapse. In this review, we summarize current research on RIP in neurons, focusing specifically on synaptic proteins where the presence and function of the ICDs have been reported. We also briefly discuss activity-driven processing of RIP substrates at the synapse and the cellular machinery that support long-distance transport of ICDs from the synapse to the nucleus. Finally, we describe future challenges in this field of research in the context of understanding the contribution of ICDs in neuronal function.
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Affiliation(s)
- Yan Jun Lee
- Lee Kong Chian School of Medicine, Nanyang Technological University, Clinical Science Building, 11 Mandalay Road, 10-01-01 M, Singapore, 308232, Singapore.,Interdisciplinary Graduate School (IGS), Nanyang Technological University, Singapore, Singapore
| | - Toh Hean Ch'ng
- Lee Kong Chian School of Medicine, Nanyang Technological University, Clinical Science Building, 11 Mandalay Road, 10-01-01 M, Singapore, 308232, Singapore. .,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
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11
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Willén K, Sroka A, Takahashi RH, Gouras GK. Heterogeneous Association of Alzheimer's Disease-Linked Amyloid-β and Amyloid-β Protein Precursor with Synapses. J Alzheimers Dis 2018; 60:511-524. [PMID: 28869466 PMCID: PMC5611798 DOI: 10.3233/jad-170262] [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] [Indexed: 11/15/2022]
Abstract
Alzheimer’s disease (AD) is increasingly viewed as a disease of synapses. Loss of synapses correlates better with cognitive decline than amyloid plaques and neurofibrillary tangles, the hallmark neuropathological lesions of AD. Soluble forms of amyloid-β (Aβ) have emerged as mediators of synapse dysfunction. Aβ binds to, accumulates, and aggregates in synapses. However, the anatomical and neurotransmitter specificity of Aβ and the amyloid-β protein precursor (AβPP) in AD remain poorly understood. In addition, the relative roles of Aβ and AβPP in the development of AD, at pre- versus post-synaptic compartments and axons versus dendrites, respectively, remain unclear. Here we use immunogold electron microscopy and confocal microscopy to provide evidence for heterogeneity in the localization of Aβ/AβPP. We demonstrate that Aβ binds to a subset of synapses in cultured neurons, with preferential binding to glutamatergic compared to GABAergic neurons. We also highlight the challenge of defining pre- versus post-synaptic localization of this binding by confocal microscopy. Further, endogenous Aβ42 accumulates in both glutamatergic and GABAergic AβPP/PS1 transgenic primary neurons, but at varying levels. Moreover, upon knock-out of presenilin 1 or inhibition of γ-secretase AβPP C-terminal fragments accumulate both pre- and post-synaptically; however earlier pre-synaptically, consistent with a higher rate of AβPP processing in axons. A better understanding of the synaptic and anatomical selectivity of Aβ/AβPP in AD can be important for the development of more effective new therapies for this major disease of aging.
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Affiliation(s)
- Katarina Willén
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Agnieszka Sroka
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | | | - Gunnar K Gouras
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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12
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Abstract
Synapse is the basic structural and functional component for neural communication in the brain. The presynaptic terminal is the structural and functionally essential area that initiates communication and maintains the continuous functional neural information flow. It contains synaptic vesicles (SV) filled with neurotransmitters, an active zone for release, and numerous proteins for SV fusion and retrieval. The structural and functional synaptic plasticity is a representative characteristic; however, it is highly vulnerable to various pathological conditions. In fact, synaptic alteration is thought to be central to neural disease processes. In particular, the alteration of the structural and functional phenotype of the presynaptic terminal is a highly significant evidence for neural diseases. In this review, we specifically describe structural and functional alteration of nerve terminals in several neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), Amyotrophic lateral sclerosis (ALS), and Huntington’s disease (HD).
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Affiliation(s)
- Jae Ryul Bae
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Korea
| | - Sung Hyun Kim
- Department of Physiology, School of Medicine, Kyung Hee University, Seoul 02447, Korea
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13
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Saadipour K, Mañucat-Tan NB, Lim Y, Keating DJ, Smith KS, Zhong JH, Liao H, Bobrovskaya L, Wang YJ, Chao MV, Zhou XF. p75 neurotrophin receptor interacts with and promotes BACE1 localization in endosomes aggravating amyloidogenesis. J Neurochem 2018; 144:302-317. [PMID: 28869759 DOI: 10.1111/jnc.14206] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 07/17/2017] [Accepted: 08/29/2017] [Indexed: 12/27/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a progressive deposition of amyloid beta (Aβ) and dysregulation of neurotrophic signaling, causing synaptic dysfunction, loss of memory, and cell death. The expression of p75 neurotrophin receptor is elevated in the brain of AD patients, suggesting its involvement in this disease. However, the exact mechanism of its action is not yet clear. Here, we show that p75 interacts with beta-site amyloid precursor protein cleaving enzyme-1 (BACE1), and this interaction is enhanced in the presence of Aβ. Our results suggest that the colocalization of BACE1 and amyloid precursor protein (APP) is increased in the presence of both Aβ and p75 in cortical neurons. In addition, the localization of APP and BACE1 in early endosomes is increased in the presence of Aβ and p75. An increased phosphorylation of APP-Thr668 and BACE1-Ser498 by c-Jun N-terminal kinase (JNK) in the presence of Aβ and p75 could be responsible for this localization. In conclusion, our study proposes a potential involvement in amyloidogenesis for p75, which may represent a future therapeutic target for AD. Cover Image for this Issue: doi. 10.1111/jnc.14163.
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Affiliation(s)
- Khalil Saadipour
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia
- Department of Human Physiology, Centre for Neuroscience, Flinders University, Adelaide, South Australia
- Departments of Cell Biology, Physiology & Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone School of Medicine, New York, NY, USA
| | - Noralyn B Mañucat-Tan
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia
| | - Yoon Lim
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia
| | - Damien J Keating
- Department of Human Physiology, Centre for Neuroscience, Flinders University, Adelaide, South Australia
| | - Kevin S Smith
- Department of Human Physiology, Centre for Neuroscience, Flinders University, Adelaide, South Australia
| | - Jin-Hua Zhong
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia
| | - Hong Liao
- New Drug Screening Centre, China Pharmaceutical University, Nanjing, China
| | - Larisa Bobrovskaya
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia
| | - Yan-Jiang Wang
- Department of Neurology and Center for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Moses V Chao
- Departments of Cell Biology, Physiology & Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone School of Medicine, New York, NY, USA
| | - Xin-Fu Zhou
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia
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14
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Regulated intramembrane proteolysis: emergent role in cell signalling pathways. Biochem Soc Trans 2017; 45:1185-1202. [PMID: 29079648 DOI: 10.1042/bst20170002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/27/2017] [Accepted: 08/29/2017] [Indexed: 12/12/2022]
Abstract
Receptor signalling events including those initiated following activation of cytokine and growth factor receptors and the well-characterised death receptors (tumour necrosis factor receptor, type 1, FasR and TRAIL-R1/2) are initiated at the cell surface through the recruitment and formation of intracellular multiprotein signalling complexes that activate divergent signalling pathways. Over the past decade, research studies reveal that many of these receptor-initiated signalling events involve the sequential proteolysis of specific receptors by membrane-bound proteases and the γ-secretase protease complexes. Proteolysis enables the liberation of soluble receptor ectodomains and the generation of intracellular receptor cytoplasmic domain fragments. The combined and sequential enzymatic activity has been defined as regulated intramembrane proteolysis and is now a fundamental signal transduction process involved in the termination or propagation of receptor signalling events. In this review, we discuss emerging evidence for a role of the γ-secretase protease complexes and regulated intramembrane proteolysis in cell- and immune-signalling pathways.
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Karelina T, Demin O, Nicholas T, Lu Y, Duvvuri S, Barton HA. A Translational Systems Pharmacology Model for Aβ Kinetics in Mouse, Monkey, and Human. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2017; 6:666-675. [PMID: 28571112 PMCID: PMC5658289 DOI: 10.1002/psp4.12211] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 03/13/2017] [Accepted: 05/18/2017] [Indexed: 01/06/2023]
Abstract
A mechanistic model of amyloid beta production, degradation, and distribution was constructed for mouse, monkey, and human, calibrated and externally verified across multiple datasets. Simulations of single‐dose avagacestat treatment demonstrate that the Aβ42 brain inhibition may exceed that in cerebrospinal fluid (CSF). The dose that achieves 50% CSF Aβ40 inhibition for humans (both healthy and with Alzheimer's disease (AD)) is about 1 mpk, one order of magnitude lower than for mouse (10 mpk), mainly because of differences in pharmacokinetics. The predicted maximal percent of brain Aβ42 inhibition after single‐dose avagacestat is higher for AD subjects (about 60%) than for healthy individuals (about 45%). The probability of achieving a normal physiological level for Aβ42 in brain (1 nM) during multiple avagacestat dosing can be increased by using a dosing regimen that achieves higher exposure. The proposed model allows prediction of brain pharmacodynamics for different species given differing dosing regimens.
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Affiliation(s)
- T Karelina
- Institute for Systems Biology, Moscow, Russia
| | - O Demin
- Institute for Systems Biology, Moscow, Russia
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16
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Dysregulation of intracellular trafficking and endosomal sorting in Alzheimer's disease: controversies and unanswered questions. Biochem J 2017; 473:1977-93. [PMID: 27407168 DOI: 10.1042/bcj20160147] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/18/2016] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of amyloid plaques in the brain consisting of an aggregated form of amyloid β-peptide (Aβ) derived from sequential amyloidogenic processing of the amyloid precursor protein (APP) by membrane-bound proteases β-site APP-cleaving enzyme 1 (BACE1) and γ-secretase. The initial processing of APP by BACE1 is re-gulated by intracellular sorting events of the enzyme, which is a prime target for therapeutic intervention. GWAS (genome-wide sequencing studies) have identified several AD-susceptibility genes that are associated with the regulation of membrane trafficking, and substantial evidence now indicates that AD is likely to arise from defective membrane trafficking in either or both of the secretory and endocytic pathways. Considerable progress has been made in defining the intracellular trafficking pathways of BACE1 and APP and the sorting signals of these membrane proteins that define their itineraries. In this review we highlight recent advances in understanding the regulation of the intracellular sorting of BACE1 and APP, discuss how dysregulation of these trafficking events may lead to enhanced generation of the neurotoxic Aβ products in AD and highlight the unresolved questions in the field.
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17
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Lian Q, Nie Y, Zhang X, Tan B, Cao H, Chen W, Gao W, Chen J, Liang Z, Lai H, Huang S, Xu Y, Jiang W, Huang P. Effects of grape seed proanthocyanidin on Alzheimer's disease in vitro and in vivo. Exp Ther Med 2016; 12:1681-1692. [PMID: 27588088 PMCID: PMC4998082 DOI: 10.3892/etm.2016.3530] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 04/21/2016] [Indexed: 11/09/2022] Open
Abstract
Grape seed proanthocyanidin (GSPA) consists of catechin, epicatechin and epicatechin gallate, which are strong antioxidants that are beneficial to health and may attenuate or prevent Alzheimer's disease (AD). In the present study, the effects of GSPA on pheochromocytoma (PC12) cell viability were determined using cell counting kit-8 and lactate dehydrogenase (LDH) assays, whereas apoptosis and mitochondrial membrane potential (Ψm) were measured via flow cytometry analysis. The effect of GSPA administration on the behavior and memory of amyloid precursor protein (APP)/presenilin-1 (PS-1) double transgenic mice was assessed using a Morris water maze. APP Aβ peptides and tau hyperphosphorylation were examined by western blotting; whereas the expression levels of PS-1 were evaluated by reverse transcription-quantitative polymerase chain reaction and compared with pathological sections stained with hematoxylin-eosin and Congo red. Data from the in vitro experiments demonstrated that GSPA significantly alleviated Aβ25–35 cytotoxicity and LDH leakage ratio, inhibited apoptosis and increased Ψm. The findings from the in vivo experiments showed a significant enhancement in cognition and spatial memory ability, an improvement in the pathology of APP and tau protein and a decrease in PS-1 mRNA expression levels. Therefore, the results of the present study indicated that GSPA may be a novel therapeutic strategy for the treatment of AD or may, at the very least, improve the quality of life of patients with AD.
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Affiliation(s)
- Qingwang Lian
- Department of Pharmacology Teaching and Research, College of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Yongsheng Nie
- Department of Pharmacology Teaching and Research, College of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Xiaoyou Zhang
- BannerBioNutraceuticals Inc., Shenzhen, Guangdong 518057, P.R. China
| | - Bo Tan
- Department of Pharmacology Teaching and Research, College of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Hongying Cao
- Department of Pharmacology Teaching and Research, College of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Wenling Chen
- BannerBioNutraceuticals Inc., Shenzhen, Guangdong 518057, P.R. China
| | - Weiming Gao
- BannerBioNutraceuticals Inc., Shenzhen, Guangdong 518057, P.R. China
| | - Jiayi Chen
- Department of Pharmacology Teaching and Research, College of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Zhijian Liang
- Department of Pharmacology Teaching and Research, College of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Huangling Lai
- Department of Pharmacology Teaching and Research, College of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Siming Huang
- Department of Pharmacology Teaching and Research, College of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Yifei Xu
- Department of Pharmacology Teaching and Research, College of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Weiwen Jiang
- Department of Pharmacology Teaching and Research, College of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
| | - Ping Huang
- Department of Pharmacology Teaching and Research, College of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, P.R. China
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18
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Kuzuya A, Zoltowska KM, Post KL, Arimon M, Li X, Svirsky S, Maesako M, Muzikansky A, Gautam V, Kovacs D, Hyman BT, Berezovska O. Identification of the novel activity-driven interaction between synaptotagmin 1 and presenilin 1 links calcium, synapse, and amyloid beta. BMC Biol 2016; 14:25. [PMID: 27036734 PMCID: PMC4818459 DOI: 10.1186/s12915-016-0248-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 03/18/2016] [Indexed: 12/20/2022] Open
Abstract
Background Synaptic loss strongly correlates with memory deterioration. Local accumulation of amyloid β (Aβ) peptide, and neurotoxic Aβ42 in particular, due to abnormal neuronal activity may underlie synaptic dysfunction, neurodegeneration, and memory impairments. To gain an insight into molecular events underlying neuronal activity-regulated Aβ production at the synapse, we explored functional outcomes of the newly discovered calcium-dependent interaction between Alzheimer’s disease-associated presenilin 1 (PS1)/γ-secretase and synaptic vesicle proteins. Results Mass spectrometry screen of mouse brain lysates identified synaptotagmin 1 (Syt1) as a novel synapse-specific PS1-binding partner that shows Ca2+-dependent PS1 binding profiles in vitro and in vivo. We found that Aβ level, and more critically, conformation of the PS1 and the Aβ42/40 ratio, are affected by Syt1 overexpression or knockdown, indicating that Syt1 and its interaction with PS1 might regulate Aβ production at the synapse. Moreover, β-secretase 1 (BACE1) stability, β- and γ-secretase activity, as well as intracellular compartmentalization of PS1 and BACE1, but not of amyloid precursor protein (APP), nicastrin (Nct), presenilin enhancer 2 (Pen-2), or synaptophysin (Syp) were altered in the absence of Syt1, suggesting a selective effect of Syt1 on PS1 and BACE1 trafficking. Conclusions Our findings identify Syt1 as a novel Ca2+-sensitive PS1 modulator that could regulate synaptic Aβ, opening avenues for novel and selective synapse targeting therapeutic strategies. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0248-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Akira Kuzuya
- MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Katarzyna M Zoltowska
- MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Kathryn L Post
- MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Muriel Arimon
- MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Xuejing Li
- MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Sarah Svirsky
- MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Masato Maesako
- MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Alona Muzikansky
- MGH Biostatistics Center, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Vivek Gautam
- MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Dora Kovacs
- MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Bradley T Hyman
- MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA
| | - Oksana Berezovska
- MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA.
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19
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P. Hurst T, Coleman-Vaughan C, Patwal I, V. McCarthy J. Regulated intramembrane proteolysis, innate immunity and therapeutic targets in Alzheimer’s disease. AIMS MOLECULAR SCIENCE 2016. [DOI: 10.3934/molsci.2016.2.138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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20
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Gautam V, D'Avanzo C, Berezovska O, Tanzi RE, Kovacs DM. Synaptotagmins interact with APP and promote Aβ generation. Mol Neurodegener 2015. [PMID: 26202512 PMCID: PMC4511450 DOI: 10.1186/s13024-015-0028-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background Accumulation of the β-amyloid peptide (Aβ) is a major pathological hallmark of Alzheimer’s disease (AD). Recent studies have shown that synaptic Aβ toxicity may directly impair synaptic function. However, proteins regulating Aβ generation at the synapse have not been characterized. Here, we sought to identify synaptic proteins that interact with the extracellular domain of APP and regulate Aβ generation. Results Affinity purification-coupled mass spectrometry identified members of the Synaptotagmin (Syt) family as novel interacting proteins with the APP ectodomain in mouse brains. Syt-1, −2 and −9 interacted with APP in cells and in mouse brains in vivo. Using a GST pull-down approach, we have further demonstrated that the Syt interaction site lies in the 108 amino acids linker region between the E1 and KPI domains of APP. Stable overexpression of Syt-1 or Syt-9 with APP in CHO and rat pheochromocytoma cells (PC12) significantly increased APP-CTF and sAPP levels, with a 2 to 3 fold increase in secreted Aβ levels in PC12 cells. Moreover, using a stable knockdown approach to reduce the expression of endogenous Syt-1 in PC12 cells, we have observed a ~ 50 % reduction in secreted Aβ generation. APP processing also decreased in these cells, shown by lower CTF levels. Lentiviral-mediated knock down of endogenous Syt-1 in mouse primary neurons also led to a significant reduction in both Aβ40 and Aβ42 generation. As secreted sAPPβ levels were significantly reduced in PC12 cells lacking Syt-1 expression, our results suggest that Syt-1 regulates Aβ generation by modulating BACE1-mediated cleavage of APP. Conclusion Altogether, our data identify the synaptic vesicle proteins Syt-1 and 9 as novel APP-interacting proteins that promote Aβ generation and thus may play an important role in the pathogenesis of AD. Electronic supplementary material The online version of this article (doi:10.1186/s13024-015-0028-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Vivek Gautam
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA.
| | - Carla D'Avanzo
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA.
| | - Oksana Berezovska
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA.
| | - Rudolph E Tanzi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA.
| | - Dora M Kovacs
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, 02129, USA.
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21
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Yetman MJ, Lillehaug S, Bjaalie JG, Leergaard TB, Jankowsky JL. Transgene expression in the Nop-tTA driver line is not inherently restricted to the entorhinal cortex. Brain Struct Funct 2015; 221:2231-49. [PMID: 25869275 DOI: 10.1007/s00429-015-1040-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 04/02/2015] [Indexed: 01/07/2023]
Abstract
The entorhinal cortex (EC) plays a central role in episodic memory and is among the earliest sites of neurodegeneration and neurofibrillary tangle formation in Alzheimer's disease. Given its importance in memory and dementia, the ability to selectively modulate gene expression or neuronal function in the EC is of widespread interest. To this end, several recent studies have taken advantage of a transgenic line in which the tetracycline transactivator (tTA) was placed under control of the neuropsin (Nop) promoter to limit transgene expression within the medial EC and pre-/parasubiculum. Although the utility of this driver is contingent on its spatial specificity, no detailed neuroanatomical analysis of its expression has yet been conducted. We therefore undertook a systematic analysis of Nop-tTA expression using a lacZ reporter and have made the complete set of histological sections available through the Rodent Brain Workbench tTA atlas, www.rbwb.org . Our findings confirm that the highest density of tTA expression is found in the EC and pre-/parasubiculum, but also reveal considerable expression in several other cortical areas. Promiscuous transgene expression may account for the appearance of pathological protein aggregates outside of the EC in mouse models of Alzheimer's disease using this driver, as we find considerable overlap between sites of delayed amyloid deposition and regions with sparse β-galactosidase reporter labeling. While different tet-responsive lines can display individual expression characteristics, our results suggest caution when designing experiments that depend on precise localization of gene products controlled by the Nop-tTA or other spatially restrictive transgenic drivers.
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Affiliation(s)
- Michael J Yetman
- Departments of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, BCM295, One Baylor Plaza, Houston, TX, 77030, USA
| | - Sveinung Lillehaug
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Jan G Bjaalie
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Trygve B Leergaard
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Joanna L Jankowsky
- Departments of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, BCM295, One Baylor Plaza, Houston, TX, 77030, USA. .,Departments of Neurology and Neurosurgery, Huffington Center on Aging, Baylor College of Medicine, Houston, TX, USA.
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22
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Liu L, Fujino K, Nishimura M. Pre-synaptic localization of the γ-secretase-inhibiting protein p24α2 in the mammalian brain. J Neurochem 2015; 133:422-31. [PMID: 25438880 DOI: 10.1111/jnc.13000] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 11/19/2014] [Accepted: 11/22/2014] [Indexed: 12/13/2022]
Abstract
Dysregulated metabolism and consequent extracellular accumulation of amyloid-β (Aβ) peptides in the brain underlie the pathogenesis of Alzheimer's disease. Extracellular Aβ in the brain parenchyma is mainly secreted from the pre-synaptic terminals of neuronal cells in a synaptic activity-dependent manner. The p24 family member p24α2 reportedly attenuates Aβ generation by inhibiting γ-secretase processing of amyloid precursor protein; however, the pattern of expression and localization of p24α2 in the brain remains unknown. We performed immunohistochemical staining and subcellular fractionation for p24α2 in the mouse brain. Immunostaining showed that p24α2 is broadly distributed in the gray matter of the central nervous system and is predominantly localized to synapses. Subcellular fractionation revealed prominent localization of p24α2 in the pre-synaptic terminals. Immunoisolation of synaptic vesicles (SV) indicated that p24α2 is condensed at active zone-docked SV. During development, p24α2 expression is highest in the post-natal period and gradually decreases with age. We also confirmed that amyloid precursor protein and γ-secretase components are localized at active zone-docked SV. Our results suggest a novel functional role for p24α2 in the regulation of synaptic transmission and synaptogenesis, and provide evidence for the participation of p24α2 in the regulation of Aβ generation and secretion in the brain. The p24 family member p24α2 attenuates amyloid-β (Aβ) generation by inhibiting the γ-secretase processing. We report that p24α2 is condensed at active zone-docked synaptic vesicles in the brain. p24α2 expression is highest in the post-natal period and gradually decreases with age. Our results suggest a novel function for p24α2 at the synapse, including the regulation of brain Aβ generation.
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Affiliation(s)
- Lei Liu
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Shiga, Japan
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Stargardt A, Swaab DF, Bossers K. The storm before the quiet: neuronal hyperactivity and Aβ in the presymptomatic stages of Alzheimer's disease. Neurobiol Aging 2015; 36:1-11. [DOI: 10.1016/j.neurobiolaging.2014.08.014] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Revised: 07/29/2014] [Accepted: 08/12/2014] [Indexed: 12/27/2022]
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Chen WT, Hsieh YF, Huang YJ, Lin CC, Lin YT, Liu YC, Lien CC, Cheng IHJ. G206D Mutation of Presenilin-1 Reduces Pen2 Interaction, Increases Aβ42/Aβ40 Ratio and Elevates ER Ca(2+) Accumulation. Mol Neurobiol 2014; 52:1835-1849. [PMID: 25394380 DOI: 10.1007/s12035-014-8969-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 10/28/2014] [Indexed: 12/23/2022]
Abstract
Early-onset familial Alzheimer's disease (AD) is most commonly associated with the mutations in presenilin-1 (PS1). PS1 is the catalytic component of the γ-secretase complex, which cleaves amyloid precursor protein to produce amyloid-β (Aβ), the major cause of AD. Presenilin enhancer 2 (Pen2) is critical for activating γ-secretase and exporting PS1 from endoplasmic reticulum (ER). Among all the familial AD-linked PS1 mutations, mutations at the G206 amino acid are the most adjacent position to the Pen2 binding site. Here, we characterized the effect of a familial AD-linked PS1 G206D mutation on the PS1-Pen2 interaction and the accompanied alteration in γ-secretase-dependent and -independent functions. We found that the G206D mutation reduced PS1-Pen2 interaction, but did not abolish γ-secretase formation and PS1 endoproteolysis. For γ-secretase-dependent function, the G206D mutation increased Aβ42 production but not Notch cleavage. For γ-secretase-independent function, this mutation disrupted the ER calcium homeostasis but not lysosomal calcium homeostasis and autophagosome maturation. Impaired ER calcium homeostasis may due to the reduced mutant PS1 level in the ER. Although this mutation did not alter the cell survival under stress, both increased Aβ42 ratio and disturbed ER calcium regulation could be the mechanisms underlying the pathogenesis of the familial AD-linked PS1 G206D mutation.
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Affiliation(s)
- Wei-Ting Chen
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan.,Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.,Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Fang Hsieh
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Yan-Jing Huang
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Che-Ching Lin
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Yen-Tung Lin
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Chao Liu
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan
| | - Cheng-Chang Lien
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan.,Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Irene Han-Juo Cheng
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan. .,Brain Research Center, National Yang-Ming University, Taipei, Taiwan. .,Infection and Immunity Research Center, National Yang-Ming University, Taipei, Taiwan. .,Immunology Center, Taipei Veterans General Hospital, Taipei, Taiwan. .,Institute of Brain Science, School of Medicine, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Taipei, 112, Taiwan.
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Wang L, Hu J, Zhao Y, Lu X, Zhang Q, Niu Q. Effects of aluminium on β-amyloid (1-42) and secretases (APP-cleaving enzymes) in rat brain. Neurochem Res 2014; 39:1338-45. [PMID: 24792732 DOI: 10.1007/s11064-014-1317-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Revised: 04/16/2014] [Accepted: 04/21/2014] [Indexed: 01/22/2023]
Abstract
Chronic administration of aluminium has been proposed as an environmental factor that may affect some pathological changes related to neurotoxicity and Alzheimer's disease (AD). The abnormal generation and deposition of β-amyloid (Aβ) in senile plaques are hallmark features in the brains of AD patients. Furthermore, Aβ is generated by the sequential cleavage of the amyloid precursor protein (APP) via the APP cleaving enzyme (α-secretase, or β-secretase) and γ-secretase. In the present study, we investigated the modulation of Aβ deposition and neurotoxicity in aluminium-maltolate-treated (0, 15, 30, 45 mmol/kg body weight via intraperitoneal injection) in experimental rats. We measured Aβ1-40 and Aβ1-42 in the cortex and hippocampus in rat brains using ELISA. Subtypes of α-secretase, β-secretase, and γ-secretase, including ADAM9, ADAM10, ADAM17 (TACE), BACE1, presenilin 1 (PS1) and nicastrin (NCT), were determined using western blotting analyses. These results indicated that aluminium-maltolate induced an AD-like behavioural deficit in rats at 30 and 45 mmol/kg body weight. Moreover, the Aβ1-42 content increased significantly, both in the cortex and hippocampus, although no changes were observed in Aβ1-40. Furthermore, ADAM9, ADAM10, and ADAM17 decreased significantly; in contrast, BACE1, PS1, and NCT showed significant increase. Taken together, these results suggest that the changes in secretases may correlate to the abnormal deposition of Aβ by aluminium in rat brains.
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Affiliation(s)
- Linping Wang
- School of Public Health, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
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26
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UV irradiation accelerates amyloid precursor protein (APP) processing and disrupts APP axonal transport. J Neurosci 2014; 34:3320-39. [PMID: 24573290 DOI: 10.1523/jneurosci.1503-13.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Overexpression and/or abnormal cleavage of amyloid precursor protein (APP) are linked to Alzheimer's disease (AD) development and progression. However, the molecular mechanisms regulating cellular levels of APP or its processing, and the physiological and pathological consequences of altered processing are not well understood. Here, using mouse and human cells, we found that neuronal damage induced by UV irradiation leads to specific APP, APLP1, and APLP2 decline by accelerating their secretase-dependent processing. Pharmacological inhibition of endosomal/lysosomal activity partially protects UV-induced APP processing implying contribution of the endosomal and/or lysosomal compartments in this process. We found that a biological consequence of UV-induced γ-secretase processing of APP is impairment of APP axonal transport. To probe the functional consequences of impaired APP axonal transport, we isolated and analyzed presumptive APP-containing axonal transport vesicles from mouse cortical synaptosomes using electron microscopy, biochemical, and mass spectrometry analyses. We identified a population of morphologically heterogeneous organelles that contains APP, the secretase machinery, molecular motors, and previously proposed and new residents of APP vesicles. These possible cargoes are enriched in proteins whose dysfunction could contribute to neuronal malfunction and diseases of the nervous system including AD. Together, these results suggest that damage-induced APP processing might impair APP axonal transport, which could result in failure of synaptic maintenance and neuronal dysfunction.
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Sotelo P, Farfán P, Benitez ML, Bu G, Marzolo MP. Sorting nexin 17 regulates ApoER2 recycling and reelin signaling. PLoS One 2014; 9:e93672. [PMID: 24705369 PMCID: PMC3976305 DOI: 10.1371/journal.pone.0093672] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 03/10/2014] [Indexed: 11/30/2022] Open
Abstract
ApoER2 is a member of the low density-lipoprotein receptor (LDL-R) family. As a receptor for reelin, ApoER2 participates in neuronal migration during development as well as synaptic plasticity and survival in the adult brain. A previous yeast two-hybrid screen showed that ApoER2 is a binding partner of sorting nexin 17 (SNX17) - a cytosolic adaptor protein that regulates the trafficking of several membrane proteins in the endosomal pathway, including LRP1, P-selectin and integrins. However, no further studies have been performed to investigate the role of SNX17 in ApoER2 trafficking and function. In this study, we present evidence based on GST pull-down and inmunoprecipitation assays that the cytoplasmic NPxY endocytosis motif of ApoER2 interacts with the FERM domain of SNX17. SNX17 stimulates ApoER2 recycling in different cell lines including neurons without affecting its endocytic rate and also facilitates the transport of ApoER2 from the early endosomes to the recycling endosomes. The reduction of SNX17 was associated with accumulation of an ApoER2 carboxy-terminal fragment (CTF). In addition, in SNX17 knockdown cells, constitutive ApoER2 degradation was not modified, whereas reelin-induced ApoER2 degradation was increased, implying that SNX17 is a regulator of the receptor's half-life. Finally, in SNX17 silenced hippocampal and cortical neurons, we underscored a positive role of this endosomal protein in the development of the dendritic tree and reelin signaling. Overall, these results establish the role of SNX17 in ApoER2 trafficking and function and aid in identifying new links between endocytic trafficking and receptor signaling.
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Affiliation(s)
- Pablo Sotelo
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Millenium Nucleus for Renerative Biology (MINREB), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pamela Farfán
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Millenium Nucleus for Renerative Biology (MINREB), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - María Luisa Benitez
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Millenium Nucleus for Renerative Biology (MINREB), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, United States of America
| | - María-Paz Marzolo
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Millenium Nucleus for Renerative Biology (MINREB), Pontificia Universidad Católica de Chile, Santiago, Chile
- * E-mail:
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28
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Lundgren JL, Ahmed S, Winblad B, Gouras GK, Tjernberg LO, Frykman S. Activity-independent release of the amyloid β-peptide from rat brain nerve terminals. Neurosci Lett 2014; 566:125-30. [PMID: 24602978 DOI: 10.1016/j.neulet.2014.02.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 02/10/2014] [Accepted: 02/23/2014] [Indexed: 01/21/2023]
Abstract
Synaptic degeneration is one of the earliest hallmarks of Alzheimer disease. The molecular mechanism underlying this degeneration is not fully elucidated but one key player appears to be the synaptotoxic amyloid β-peptide (Aβ). The exact localization of the production of Aβ and the mechanisms whereby Aβ is released remain elusive. We have earlier shown that Aβ can be produced in crude synaptic vesicle fractions and it has been reported that increased synaptic activity results in increased secreted but decreased intracellular Aβ levels. Therefore, we considered whether Aβ could be produced in synaptic vesicles and/or released through the same mechanisms as neurotransmitters in synaptic vesicle exocytosis. Small amounts of Aβ were found to be produced in pure synaptic vesicle preparations. We also studied the release of glutamate and Aβ from rat cortical nerve terminals (synaptosomes). We found that large amounts of Aβ were secreted from non-stimulated synaptosomes, from which glutamate was not released. On the contrary, we could not detect any differences in Aβ release between non-stimulated synaptosomes and synaptosomes stimulated with KCl or 4-aminopyridine, whereas glutamate release was readily inducible in this system. To conclude, our results indicate that the major release mechanism of Aβ from isolated nerve terminals differs from the synaptic release of glutamate and that the activity-dependent increase of secreted Aβ, reported by several groups using intact cells, is likely dependent on post-synaptic events, trafficking and/or protein synthesis mechanisms.
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Affiliation(s)
- Jolanta L Lundgren
- Karolinska Institutet, Department of Neurobiology, Care Science and Society, Center for Alzheimer Research, Novum level 5, 141 86 Stockholm, Sweden
| | - Saheeb Ahmed
- European Neuroscience Institute, Grisebachstrasse 5, 37077 Göttingen, Germany
| | - Bengt Winblad
- Karolinska Institutet, Department of Neurobiology, Care Science and Society, Center for Alzheimer Research, Novum level 5, 141 86 Stockholm, Sweden
| | - Gunnar K Gouras
- Lund University, Department of Experimental Medical Science, Experimental Dementia Research Unit, Sölveg 19, BMC B12, 221 84 Lund, Sweden
| | - Lars O Tjernberg
- Karolinska Institutet, Department of Neurobiology, Care Science and Society, Center for Alzheimer Research, Novum level 5, 141 86 Stockholm, Sweden
| | - Susanne Frykman
- Karolinska Institutet, Department of Neurobiology, Care Science and Society, Center for Alzheimer Research, Novum level 5, 141 86 Stockholm, Sweden.
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29
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Impaired endolysosomal function disrupts Notch signalling in optic nerve astrocytes. Nat Commun 2013; 4:1629. [PMID: 23535650 DOI: 10.1038/ncomms2624] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 02/20/2013] [Indexed: 12/28/2022] Open
Abstract
Astrocytes migrate from the optic nerve into the inner retina, forming a template upon which retinal vessels develop. In the Nuc1 rat, mutation in the gene encoding βA3/A1-crystallin disrupts both Notch signalling in astrocytes and formation of the astrocyte template. Here we show that loss of βA3/A1-crystallin in astrocytes does not impede Notch ligand binding or extracellular cleavages. However, it affects vacuolar-type proton ATPase (V-ATPase) activity, thereby compromising acidification of the endolysosomal compartments, leading to reduced γ-secretase-mediated processing and release of the Notch intracellular domain (NICD). Lysosomal-mediated degradation of Notch is also impaired. These defects decrease the level of NICD in the nucleus, inhibiting the expression of Notch target genes. Overexpression of βA3/A1-crystallin in those same astrocytes restored V-ATPase activity and normal endolysosomal acidification, thereby increasing the levels of γ-secretase to facilitate optimal Notch signalling. We postulate that βA3/A1-crystallin is essential for normal endolysosomal acidification, and thereby, normal activation of Notch signalling in astrocytes.
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Smolarkiewicz M, Skrzypczak T, Wojtaszek P. The very many faces of presenilins and the γ-secretase complex. PROTOPLASMA 2013; 250:997-1011. [PMID: 23504135 PMCID: PMC3788181 DOI: 10.1007/s00709-013-0494-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 03/01/2013] [Indexed: 05/02/2023]
Abstract
Presenilin is a central, catalytic component of the γ-secretase complex which conducts intramembrane cleavage of various protein substrates. Although identified and mainly studied through its role in the development of amyloid plaques in Alzheimer disease, γ-secretase has many other important functions. The complex seems to be evolutionary conserved throughout the Metazoa, but recent findings in plants and Dictyostelium discoideum as well as in archeons suggest that its evolution and functions might be much more diversified than previously expected. In this review, a selective survey of the multitude of functions of presenilins and the γ-secretase complex is presented. Following a brief overview of γ-secretase structure, assembly and maturation, three functional aspects are analyzed: (1) the role of γ-secretase in autophagy and phagocytosis; (2) involvement of the complex in signaling related to endocytosis; and (3) control of calcium fluxes by presenilins.
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Affiliation(s)
- Michalina Smolarkiewicz
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Tomasz Skrzypczak
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Przemysław Wojtaszek
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
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31
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Schedin-Weiss S, Inoue M, Teranishi Y, Yamamoto NG, Karlström H, Winblad B, Tjernberg LO. Visualizing active enzyme complexes using a photoreactive inhibitor for proximity ligation--application on γ-secretase. PLoS One 2013; 8:e63962. [PMID: 23717518 PMCID: PMC3663845 DOI: 10.1371/journal.pone.0063962] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 04/09/2013] [Indexed: 11/20/2022] Open
Abstract
Here, we present a highly sensitive method to study protein-protein interactions and subcellular location selectively for active multicomponent enzymes. We apply the method on γ-secretase, the enzyme complex that catalyzes the cleavage of the amyloid precursor protein (APP) to generate amyloid β-peptide (Aβ), the major causative agent in Alzheimer disease (AD). The novel assay is based on proximity ligation, which can be used to study protein interactions in situ with very high sensitivity. In traditional proximity ligation assay (PLA), primary antibody recognition is typically accompanied by oligonucleotide-conjugated secondary antibodies as detection probes. Here, we first performed PLA experiments using antibodies against the γ-secretase components presenilin 1 (PS1), containing the catalytic site residues, and nicastrin, suggested to be involved in substrate recognition. To selectively study the interactions of active γ-secretase, we replaced one of the primary antibodies with a photoreactive γ-secretase inhibitor containing a PEG linker and a biotin group (GTB), and used oligonucleotide-conjugated streptavidin as a probe. Interestingly, significantly fewer interactions were detected with the latter, novel, assay, which is a reasonable finding considering that a substantial portion of PS1 is inactive. In addition, the PLA signals were located more peripherally when GTB was used instead of a PS1 antibody, suggesting that γ-secretase matures distal from the perinuclear ER region. This novel technique thus enables highly sensitive protein interaction studies, determines the subcellular location of the interactions, and differentiates between active and inactive γ-secretase in intact cells. We suggest that similar PLA assays using enzyme inhibitors could be useful also for other enzyme interaction studies.
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Affiliation(s)
- Sophia Schedin-Weiss
- KI-Alzheimer Disease Research Center-KI-ADRC, Karolinska Institutet, Department of Neurobiology, Care Sciences and Society-NVS, Novum Level 5, Stockholm, Sweden.
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Plasma renin-angiotensin system-regulating aminopeptidase activities are modified in early stage Alzheimer's disease and show gender differences but are not related to apolipoprotein E genotype. Exp Gerontol 2013; 48:557-64. [PMID: 23500679 DOI: 10.1016/j.exger.2013.03.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 03/05/2013] [Accepted: 03/07/2013] [Indexed: 12/25/2022]
Abstract
Alterations in blood pressure and components of the renin-angiotensin system (RAS) contribute to the development and progression of Alzheimer's disease (AD), resulting in changes that can lead or contribute to cognitive decline. Aspartyl aminopeptidase (ASAP), aminopeptidase A (APA), aminopeptidase N (APN) and aminopeptidase B (APB) catabolise circulating angiotensins, whereas insulin-regulated aminopeptidase (IRAP) has been described as the AT4 receptor. We have found in AD patients a significant decrease of APA activity in men but not in women, and of APN, APB and IRAP in both genders, when compared with control subjects. No changes were found in ASAP activity. Also, APN, APB and IRAP but not APA correlated with the Mini-Mental test, but no relationship with APOE genotype was found. We conclude that several components of the RAS are modified in AD patients, with gender differences. Furthermore, ROC analysis indicates that APN, APB and IRAP activities could be useful non-invasive biomarkers of AD from the earliest stages.
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Liu F, Xue ZQ, Deng SH, Kun X, Luo XG, Patrylo PR, Rose GM, Cai H, Struble RG, Cai Y, Yan XX. γ-secretase binding sites in aged and Alzheimer's disease human cerebrum: the choroid plexus as a putative origin of CSF Aβ. Eur J Neurosci 2013; 37:1714-25. [PMID: 23432732 DOI: 10.1111/ejn.12159] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 12/15/2012] [Accepted: 01/17/2013] [Indexed: 01/05/2023]
Abstract
Deposition of β -amyloid (Aβ) peptides, cleavage products of β-amyloid precursor protein (APP) by β-secretase-1 (BACE1) and γ-secretase, is a neuropathological hallmark of Alzheimer's disease (AD). γ-Secretase inhibition is a therapeutical anti-Aβ approach, although changes in the enzyme's activity in AD brain are unclear. Cerebrospinal fluid (CSF) Aβ peptides are thought to derive from brain parenchyma and thus may serve as biomarkers for assessing cerebral amyloidosis and anti-Aβ efficacy. The present study compared active γ-secretase binding sites with Aβ deposition in aged and AD human cerebrum, and explored the possibility of Aβ production and secretion by the choroid plexus (CP). The specific binding density of [(3) H]-L-685,458, a radiolabeled high-affinity γ-secretase inhibitor, in the temporal neocortex and hippocampal formation was similar for AD and control cases with similar ages and post-mortem delays. The CP in post-mortem samples exhibited exceptionally high [(3) H]-L-685,458 binding density, with the estimated maximal binding sites (Bmax) reduced in the AD relative to control groups. Surgically resected human CP exhibited APP, BACE1 and presenilin-1 immunoreactivity, and β-site APP cleavage enzymatic activity. In primary culture, human CP cells also expressed these amyloidogenic proteins and released Aβ40 and Aβ42 into the medium. Overall, our results suggest that γ-secretase activity appears unaltered in the cerebrum in AD and is not correlated with regional amyloid plaque pathology. The CP appears to be a previously unrecognised non-neuronal contributor to CSF Aβ, probably at reduced levels in AD.
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Affiliation(s)
- Fei Liu
- Department of Neurosurgery, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
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Cuello AC, Allard S, Ferretti MT. Evidence for the accumulation of Abeta immunoreactive material in the human brain and in transgenic animal models. Life Sci 2012; 91:1141-7. [PMID: 22705309 DOI: 10.1016/j.lfs.2012.05.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 05/11/2012] [Accepted: 05/24/2012] [Indexed: 12/19/2022]
Abstract
In this review we highlight the evidence for an intracellular origin of Abeta (Aβ) amyloid peptides as well as the observations for a pathological accumulation of these peptides in Alzheimer's disease and Down syndrome, as well as in transgenic animal models. We deliberate on the controversy as to whether the intracellular Aβ immunoreactive material is simply an accumulation of unprocessed full length amyloid precursor protein (APP) or a mix of processed APP fragments including Aβ. Finally, we discuss the possible pathological significance of these intracellular APP fragments and the expected future research directions regarding this thought-provoking problem.
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Affiliation(s)
- A Claudio Cuello
- Department of Pharmacology and Therapeutics, McGill University, 3655 Sir William Osler Promenade, Room 1210, Montreal, Quebec, Canada.
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35
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Endolysosome involvement in LDL cholesterol-induced Alzheimer's disease-like pathology in primary cultured neurons. Life Sci 2012; 91:1159-68. [PMID: 22580286 DOI: 10.1016/j.lfs.2012.04.039] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 04/19/2012] [Accepted: 04/24/2012] [Indexed: 12/26/2022]
Abstract
AIMS Elevated levels of circulating cholesterol are extrinsic factors contributing to the pathogenesis of sporadic Alzheimer's disease (AD). We showed previously that rabbits fed a cholesterol-enriched diet exhibited blood-brain barrier (BBB) dysfunction, increased accumulation of apolipoprotein B (ApoB) in brain neurons, and endolysosomes in brain had disturbed structures and functions. These effects were linked to increased amyloid beta (Aβ) production, increased tau-pathology, and disrupted synaptic integrity. Because pathological changes to endolysosomes represent a very early event in sporadic AD, we determined here the extent to which ApoB-containing LDL cholesterol altered the structure and function of endolysosomes and contributed to the development of AD-like pathology in primary cultured neurons. MAIN METHODS Cholesterol distribution and endolysosome morphology were determined histologically. Endolysosome pH was measured ratio-metrically with LysoSensor dye. Endolysosome enzyme activity was measured for acid phosphatase, cathepsins B and D, and beta-site APP cleaving enzyme 1 (BACE-1). AD-like pathologies, including increased production of Aβ, increased tau-pathology, and disrupted synaptic integrity were determined using ELISA, immunoblotting, and immunostaining techniques. KEY FINDINGS Treatment of neurons with ApoB-containing LDL cholesterol increased endolysosome accumulation of cholesterol, enlarged endolysosomes, and elevated endolysosome pH. In addition, ApoB-containing LDL cholesterol increased endolysosome accumulation of BACE-1, enhanced BACE-1 activity, increased Aβ levels, increased levels of phosphorylated tau, and decreased levels of synaptophysin. SIGNIFICANCE Our findings suggest strongly that alterations in the structure and function of endolysosomes play a key role in the exhibition of pathological features of AD that result from neuronal exposure to ApoB-containing LDL cholesterol.
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36
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Haass C, Kaether C, Thinakaran G, Sisodia S. Trafficking and proteolytic processing of APP. Cold Spring Harb Perspect Med 2012; 2:a006270. [PMID: 22553493 PMCID: PMC3331683 DOI: 10.1101/cshperspect.a006270] [Citation(s) in RCA: 761] [Impact Index Per Article: 58.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Accumulations of insoluble deposits of amyloid β-peptide are major pathological hallmarks of Alzheimer disease. Amyloid β-peptide is derived by sequential proteolytic processing from a large type I trans-membrane protein, the β-amyloid precursor protein. The proteolytic enzymes involved in its processing are named secretases. β- and γ-secretase liberate by sequential cleavage the neurotoxic amyloid β-peptide, whereas α-secretase prevents its generation by cleaving within the middle of the amyloid domain. In this chapter we describe the cell biological and biochemical characteristics of the three secretase activities involved in the proteolytic processing of the precursor protein. In addition we outline how the precursor protein maturates and traffics through the secretory pathway to reach the subcellular locations where the individual secretases are preferentially active. Furthermore, we illuminate how neuronal activity and mutations which cause familial Alzheimer disease affect amyloid β-peptide generation and therefore disease onset and progression.
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Affiliation(s)
- Christian Haass
- DZNE-German Center for Neurodegenerative Diseases, 80336 Munich, Germany; Adolf Butenandt-Institute, Biochemistry, Ludwig-Maximilians University, 80336 Munich, Germany.
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Frykman S, Teranishi Y, Hur JY, Sandebring A, Yamamoto NG, Ancarcrona M, Nishimura T, Winblad B, Bogdanovic N, Schedin-Weiss S, Kihara T, Tjernberg LO. Identification of two novel synaptic γ-secretase associated proteins that affect amyloid β-peptide levels without altering Notch processing. Neurochem Int 2012; 61:108-18. [PMID: 22521230 DOI: 10.1016/j.neuint.2012.03.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 03/13/2012] [Accepted: 03/26/2012] [Indexed: 12/15/2022]
Abstract
Synaptic degeneration is one of the earliest hallmarks of Alzheimer disease (AD) and results in loss of cognitive function. One of the causative agents for the synaptic degeneration is the amyloid β-peptide (Aβ), which is formed from its precursor protein by two sequential cleavages mediated by β- and γ-secretase. We have earlier shown that γ-secretase activity is enriched in synaptic compartments, suggesting that the synaptotoxic Aβ is produced locally. Proteins that interact with γ-secretase at the synapse and regulate the production of Aβ can therefore be potential therapeutic targets. We used a recently developed affinity purification approach to identify γ-secretase associated proteins (GSAPs) in synaptic membranes and synaptic vesicles prepared from rat brain. Liquid chromatography-tandem mass spectrometry analysis of the affinity purified samples revealed the known γ-secretase components presenilin-1, nicastrin and Aph-1b along with a number of novel potential GSAPs. To investigate the effect of these GSAPs on APP processing, we performed siRNA experiments to knock down the expression of the GSAPs and measured the Aβ levels. Silencing of NADH dehydrogenase [ubiquinone] iron-sulfur protein 7 (NDUFS7) resulted in a decrease in Aβ levels whereas silencing of tubulin polymerization promoting protein (TPPP) resulted in an increase in Aβ levels. Treatment with γ-secretase inhibitors often results in Notch-related side effects and therefore we also studied the effect of the siRNAs on Notch processing. Interestingly, silencing of TPPP or NDUFS7 did not affect cleavage of Notch. We also studied the expression of TPPP and NDUFS7 in control and AD brain and found NDUFS7 to be highly expressed in vulnerable neurons such as pyramidal neurons in the hippocampus, whereas TPPP was found to accumulate in intraneuronal granules and fibrous structures in hippocampus from AD cases. In summary, we here report on two proteins, TPPP and NDUFS7, which interact with γ-secretase and alter the Aβ levels without affecting Notch cleavage.
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Affiliation(s)
- Susanne Frykman
- Karolinska Institutet Alzheimer Disease Research Center (KI-ADRC), Novum Level 5, 141 86 Stockholm, Sweden.
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Sokolow S, Henkins KM, Bilousova T, Miller CA, Vinters HV, Poon W, Cole GM, Gylys KH. AD synapses contain abundant Aβ monomer and multiple soluble oligomers, including a 56-kDa assembly. Neurobiol Aging 2011; 33:1545-55. [PMID: 21741125 DOI: 10.1016/j.neurobiolaging.2011.05.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 05/05/2011] [Accepted: 05/20/2011] [Indexed: 10/18/2022]
Abstract
Much evidence indicates that soluble amyloid beta (Aβ) oligomers are key mediators of early cognitive loss, but the localization and key peptide species remain unclear. We have used flow cytometry analysis to demonstrate that surviving Alzheimer's disease (AD) synapses accumulate both Aβ and phosphorylated tau (p-tau). The present experiments use peptide-specific X-map assays and Western blot analyses to identify the Aβ peptide species in synaptosome-enriched samples from normal human subjects, neurologic controls, and AD cases. Aβ40 peptide levels did not vary, but both Aβ42 and Aβ oligomers were increased in soluble AD extracts, with oligomer levels 20-fold higher in aqueous compared with detergent extracts. In Western blot analysis, a ladder of sodium dodecyl sulfate (SDS)-stable oligomers was observed in AD cases, varying in size from monomer, the major peptide observed, to larger assemblies up to about 200 kDa and larger. Multiple oligomers, including monomer, small oligomers, a 56-kDa assembly, and amyloid precursor protein (APP) were correlated with the Aβ level measured in flow cytometry-purified synaptosomes. These results suggest that multiple amyloid precursor protein processing pathways are active in AD synapses and multiple soluble oligomeric assemblies may contribute to synaptic dysfunction.
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Affiliation(s)
- Sophie Sokolow
- UCLA School of Nursing and Mary S Easton Center for Alzheimer's Research, Los Angeles, CA, USA
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Winblad B, Giacobini E, Frölich L, Friedhoff LT, Bruinsma G, Becker RE, Greig NH. Phenserine efficacy in Alzheimer's disease. J Alzheimers Dis 2011; 22:1201-8. [PMID: 20930279 DOI: 10.3233/jad-2010-101311] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
To gather preliminary evidence in Alzheimer's disease (AD) for the efficacy of phenserine, a non-competitive acetylcholinesterase inhibitor that has independent modulatory effects on amyloid-β generation, a 12-week comparison of patients receiving phenserine (10 and 15 mg BID) or placebo was conducted under double-blind conditions. Patients who completed 12 weeks of the double-blind before others were continued in the double-blind to determine longer-term treatment effects. At 12 weeks, mean ADAS-cog (AD assessment scale-cognitive) changes from baseline were -2.5 and -1.9 for high-dose phenserine (n=83) and placebo (n=81) groups, respectively, a non-statistically significant improvement for the high-dose phenserine group relative to placebo. CIBIC+ (clinician's interview based impression of change + caregiver's input) values for the high-dose and placebo groups were similar at 12 weeks. For patients who received more than 12 weeks of therapy, the ADAS-cog changes were -3.18 and -0.66 for the high-dose phenserine (n=52) and placebo (n=63) groups, respectively, a difference achieving statistical significance (p=0.0286). After 12 weeks, CIBIC+ values were 3.59 and 3.95 for the high-dose (n=54) and placebo (n=66) groups respectively (p=0.0568). These results from this short-term study are consistent with phenserine potentially benefiting mild to moderate Alzheimer's disease symptomatically but do not address possible amyloid metabolic mediated effects on disease processes in AD.
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Affiliation(s)
- Bengt Winblad
- Alzheimer's Disease Research Center, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
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Groemer TW, Thiel CS, Holt M, Riedel D, Hua Y, Hüve J, Wilhelm BG, Klingauf J. Amyloid precursor protein is trafficked and secreted via synaptic vesicles. PLoS One 2011; 6:e18754. [PMID: 21556148 PMCID: PMC3083403 DOI: 10.1371/journal.pone.0018754] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 03/16/2011] [Indexed: 02/04/2023] Open
Abstract
A large body of evidence has implicated amyloid precursor protein (APP) and its proteolytic derivatives as key players in the physiological context of neuronal synaptogenesis and synapse maintenance, as well as in the pathology of Alzheimer's Disease (AD). Although APP processing and release are known to occur in response to neuronal stimulation, the exact mechanism by which APP reaches the neuronal surface is unclear. We now demonstrate that a small but relevant number of synaptic vesicles contain APP, which can be released during neuronal activity, and most likely represent the major exocytic pathway of APP. This novel finding leads us to propose a revised model of presynaptic APP trafficking that reconciles existing knowledge on APP with our present understanding of vesicular release and recycling.
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Affiliation(s)
- Teja W. Groemer
- Department of Membrane Biophysics, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
- Department of Psychiatry and Psychotherapy, University of Erlangen,
Erlangen, Germany
| | - Cora S. Thiel
- Department of Membrane Biophysics, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
- Institute of Medical Physics and Biophysics, University of Münster,
Münster, Germany
| | - Matthew Holt
- Department of Neurobiology, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
- * E-mail: (MH); (JK)
| | - Dietmar Riedel
- Electron Microscopy Group, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
| | - Yunfeng Hua
- Department of Membrane Biophysics, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
- Institute of Medical Physics and Biophysics, University of Münster,
Münster, Germany
| | - Jana Hüve
- Fluorescence Microscopy Facility Münster, Institute of Medical
Physics and Biophysics, University of Münster, Münster,
Germany
| | - Benjamin G. Wilhelm
- Department of Membrane Biophysics, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
| | - Jürgen Klingauf
- Department of Membrane Biophysics, Max Planck Institute for Biophysical
Chemistry, Göttingen, Germany
- Institute of Medical Physics and Biophysics, University of Münster,
Münster, Germany
- * E-mail: (MH); (JK)
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Zhu D, Shi J, Zhang Y, Wang B, Liu W, Chen Z, Tong Q. Central angiotensin II stimulation promotes β amyloid production in Sprague Dawley rats. PLoS One 2011; 6:e16037. [PMID: 21297982 PMCID: PMC3030571 DOI: 10.1371/journal.pone.0016037] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 12/05/2010] [Indexed: 11/29/2022] Open
Abstract
Background Stress and various stress hormones, including catecholamines and glucocorticoids, have recently been implicated in the pathogenesis of Alzheimer's disease (AD), which represents the greatest unresolved medical challenge in neurology. Angiotensin receptor blockers have shown benefits in AD and prone-to-AD animals. However, the mechanisms responsible for their efficacy remain unknown, and no studies have directly addressed the role of central angiotensin II (Ang II), a fundamental stress hormone, in the pathogenesis of AD. The present study focused on the role of central Ang II in amyloidogenesis, the critical process in AD neuropathology, and aimed to provide direct evidence for the role of this stress hormone in the pathogenesis of AD. Methodology/Principal Findings Increased central Ang II levels during stress response were modeled by intracerebroventricular (ICV) administration of graded doses of Ang II (6 ng/hr low dose, 60 ng/hr medium dose, and 600 ng/hr high dose, all delivered at a rate of 0.25 µl/hr) to male Sprague Dawley rats (280–310 g) via osmotic pumps. After 1 week of continuous Ang II infusion, the stimulation of Ang II type 1 receptors was accompanied by the modulation of amyloid precursor protein, α-, β-and γ-secretase, and increased β amyloid production. These effects could be completely abolished by concomitant ICV infusion of losartan, indicating that central Ang II played a causative role in these alterations. Conclusions/Significance Central Ang II is essential to the stress response, and the results of this study suggest that increased central Ang II levels play an important role in amyloidogenesis during stress, and that central Ang II-directed stress prevention and treatment might represent a novel anti-AD strategy.
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Affiliation(s)
- Donglin Zhu
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, People's Republic of China
| | - Jingping Shi
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, People's Republic of China
- * E-mail:
| | - Yingdong Zhang
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, People's Republic of China
| | - Bianrong Wang
- Department of Neurology, School of Medicine, Nanjing University, Nanjing, People's Republic of China
| | - Wei Liu
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, People's Republic of China
| | - Zhicong Chen
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, People's Republic of China
| | - Qiang Tong
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, People's Republic of China
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Mattsson N, Zetterberg H, Bianconi S, Yanjanin NM, Fu R, Månsson JE, Porter FD, Blennow K. Gamma-secretase-dependent amyloid-beta is increased in Niemann-Pick type C: a cross-sectional study. Neurology 2010; 76:366-72. [PMID: 21205675 DOI: 10.1212/wnl.0b013e318208f4ab] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
OBJECTIVE Niemann-Pick disease type C (NPC) is an inherited disorder characterized by intracellular accumulation of lipids such as cholesterol and glycosphingolipids in endosomes and lysosomes. This accumulation induces progressive degeneration of the nervous system. NPC shows some intriguing similarities with Alzheimer disease (AD), including neurofibrillary tangles, but patients with NPC generally lack amyloid-β (Aβ) plaques. Lipids affect γ-secretase-dependent amyloid precursor protein (APP) metabolism that generates Aβ in vitro, but this has been difficult to prove in vivo. Our aim was to assess the effect of altered lipid constituents in neuronal membranes on amyloidogenic APP processing in humans. METHODS We examined Aβ in CSF from patients with NPC (n = 38) and controls (n = 14). CSF was analyzed for Aβ(38), Aβ(40), Aβ(42), α-cleaved soluble APP, β-cleaved soluble APP, total-tau, and phospho-tau. RESULTS Aβ release was markedly increased in NPC, with a shift toward the Aβ(42) isoform. Levels of α- and β-cleaved soluble APP were similar in patients and controls. Patients with NPC had increased total-tau. Patients on treatment with miglustat (n = 18), a glucosylceramide synthase blocker, had lower Aβ(42) and total-tau than untreated patients. CONCLUSION Increased CSF levels of Aβ(38), Aβ(40), and Aβ(42) and unaltered levels of β-cleaved soluble APP are consistent with increased γ-secretase-dependent Aβ release in the brains of patients with NPC. These results provide the first in vivo evidence that neuronal lipid accumulation facilitates γ-secretase-dependent Aβ production in humans and may be of relevance to AD pathogenesis.
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Affiliation(s)
- N Mattsson
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy, University of Gothenburg, Mölndal, Sweden.
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Parent AT, Thinakaran G. Modeling presenilin-dependent familial Alzheimer's disease: emphasis on presenilin substrate-mediated signaling and synaptic function. Int J Alzheimers Dis 2010; 2010:825918. [PMID: 20798900 PMCID: PMC2925324 DOI: 10.4061/2010/825918] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 06/17/2010] [Indexed: 11/24/2022] Open
Abstract
Mutations in PSEN genes, which encode presenilin proteins, cause familial early-onset Alzheimer's disease (AD). Transgenic mouse models based on coexpression of familial AD-associated presenilin and amyloid precursor protein variants successfully mimic characteristic pathological features of AD, including plaque formation, synaptic dysfunction, and loss of memory. Presenilins function as the catalytic subunit of gamma-secretase, the enzyme that catalyzes intramembraneous proteolysis of amyloid precursor protein to release beta-amyloid peptides. Familial AD-associated mutations in presenilins alter the site of gamma-secretase cleavage in a manner that increases the generation of longer and highly fibrillogenic beta-amyloid peptides. In addition to amyloid precursor protein, gamma-secretase catalyzes intramembrane proteolysis of many other substrates known to be important for synaptic function. This paper focuses on how various animal models have enabled us to elucidate the physiological importance of diverse gamma-secretase substrates, including amyloid precursor protein and discusses their roles in the context of cellular signaling and synaptic function.
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Affiliation(s)
- Angèle T. Parent
- Department of Neurobiology, The University of Chicago, 924 East 57th Street, Chicago, IL 60637, USA
| | - Gopal Thinakaran
- Department of Neurobiology, The University of Chicago, 924 East 57th Street, Chicago, IL 60637, USA
- Department of Neurology, The University of Chicago, 924 East 57th Street, Chicago, IL 60637, USA
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