1
|
Yin T, Yesiltepe M, D'Adamio L. Functional BRI2-TREM2 interactions in microglia: implications for Alzheimer's and related dementias. EMBO Rep 2024; 25:1326-1360. [PMID: 38347225 PMCID: PMC10933458 DOI: 10.1038/s44319-024-00077-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 01/17/2024] [Accepted: 01/19/2024] [Indexed: 03/14/2024] Open
Abstract
ITM2B/BRI2 mutations cause Alzheimer's Disease (AD)-related dementias. We observe heightened ITM2B/BRI2 expression in microglia, a pivotal cell type in AD due to risk-increasing variants in the microglial gene TREM2. Single-cell RNA-sequencing demonstrates a Trem2/Bri2-dependent microglia cluster, underscoring their functional interaction. α-secretase cleaves TREM2 into TREM2-CTF and sTREM2. As BRI2 hinders α-secretase cleavage of the AD-related Aβ-Precursor-Protein, we probed whether BRI2 influences TREM2 processing. Our findings indicate a BRI2-TREM2 interaction that inhibits TREM2 processing in heterologous cells. Recombinant BRI2 and TREM2 proteins demonstrate a direct, cell-free BRI2-TREM2 ectodomain interaction. Constitutive and microglial-specific Itm2b-Knock-out mice, and Itm2b-Knock-out primary microglia provide evidence that Bri2 reduces Trem2 processing, boosts Trem2 mRNA expression, and influences Trem2 protein levels through α-secretase-independent pathways, revealing a multifaceted BRI2-TREM2 functional interaction. Moreover, a mutant Itm2b dementia mouse model exhibits elevated Trem2-CTF and sTrem2, mirroring sTREM2 increases in AD patients. Lastly, Bri2 deletion reduces phagocytosis similarly to a pathogenic TREM2 variant that enhances processing. Given BRI2's role in regulating Aβ-Precursor-Protein and TREM2 functions, it holds promise as a therapeutic target for AD and related dementias.
Collapse
Affiliation(s)
- Tao Yin
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 205 South Orange Ave, Newark, NJ, 07103, USA.
| | - Metin Yesiltepe
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 205 South Orange Ave, Newark, NJ, 07103, USA
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 205 South Orange Ave, Newark, NJ, 07103, USA.
| |
Collapse
|
2
|
Smirnova EV, Timofeev VI, Rakitina TV, Petrenko DE, Elmeeva OS, Saratov GA, Kudriaeva AA, Bocharov EV, Belogurov AA. Myelin Basic Protein Attenuates Furin-Mediated Bri2 Cleavage and Postpones Its Membrane Trafficking. Int J Mol Sci 2024; 25:2608. [PMID: 38473856 DOI: 10.3390/ijms25052608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/15/2024] [Accepted: 02/20/2024] [Indexed: 03/14/2024] Open
Abstract
Myelin basic protein (MBP) is the second most abundant protein in the central nervous system and is responsible for structural maintenance of the myelin sheath covering axons. Previously, we showed that MBP has a more proactive role in the oligodendrocyte homeostasis, interacting with membrane-associated proteins, including integral membrane protein 2B (ITM2B or Bri2) that is associated with familial dementias. Here, we report that the molecular dynamics of the in silico-generated MBP-Bri2 complex revealed that MBP covers a significant portion of the Bri2 ectodomain, assumingly trapping the furin cleavage site, while the surface of the BRICHOS domain, which is responsible for the multimerization and activation of the Bri2 high-molecular-weight oligomer chaperone function, remains unmasked. These observations were supported by the co-expression of MBP with Bri2, its mature form, and disease-associated mutants, which showed that in mammalian cells, MBP indeed modulates the post-translational processing of Bri2 by restriction of the furin-catalyzed release of its C-terminal peptide. Moreover, we showed that the co-expression of MBP and Bri2 also leads to an altered cellular localization of Bri2, restricting its membrane trafficking independently of the MBP-mediated suppression of the Bri2 C-terminal peptide release. Further investigations should elucidate if these observations have physiological meaning in terms of Bri2 as a MBP chaperone activated by the MBP-dependent postponement of Bri2 membrane trafficking.
Collapse
Affiliation(s)
- Evgeniya V Smirnova
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | | | - Tatiana V Rakitina
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Dmitry E Petrenko
- National Research Centre "Kurchatov Institute", 123182 Moscow, Russia
| | - Olga S Elmeeva
- Department of Chemistry and Technology of Biologically Active Compounds, Medical and Organic Chemistry Named after N.A. Preobrazhensky, Lomonosov Institute of Fine Chemical Technologies, MIREA-Russian Technological University, 119571 Moscow, Russia
| | - George A Saratov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology (National Research University), 141701 Dolgoprudny, Moscow Region, Russia
| | - Anna A Kudriaeva
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Eduard V Bocharov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology (National Research University), 141701 Dolgoprudny, Moscow Region, Russia
| | - Alexey A Belogurov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Department of Biological Chemistry, Federal State Budgetary Educational Institution of Higher Education "Russian University of Medicine" of the Ministry of Health of the Russian Federation, 127473 Moscow, Russia
| |
Collapse
|
3
|
D'Adamio L. Transfixed by transgenics: how pathology assumptions are slowing progress in Alzheimer's disease and related dementia research. EMBO Mol Med 2023; 15:e18479. [PMID: 37750482 PMCID: PMC10630870 DOI: 10.15252/emmm.202318479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/31/2023] [Accepted: 09/08/2023] [Indexed: 09/27/2023] Open
Abstract
Model organisms of human diseases are invaluable tools for unraveling pathogenic mechanisms, identifying potential targets for drug development, and evaluating the therapeutic efficacy of candidates in preclinical trials. The utility of model organisms hinges upon their ability to faithfully replicate the underlying pathogenic mechanisms of the human disease. For rodent models of Alzheimer's disease (AD) and AD-related dementias (ADRD), the limited translatability to human disease raises concerns about their overall utility. What factors contribute to this limitation? Is AD inherently too complex to be accurately modeled in nonhumans? Is the divergence between rodent brains and the human brain so pronounced that rodents are unsuitable as model organisms for AD? Or is it plausible that the commonly used rodent models don't capture the genuine pathogenic mechanisms underlying these diseases? This editorial discusses the challenges associated with transgenic models of AD and ADRD and offers some alternative approaches.
Collapse
Affiliation(s)
- Luciano D'Adamio
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, RutgersThe State University of New JerseyNewarkNJUSA
| |
Collapse
|
4
|
Yin T, D’Adamio L. BRI2-mediated regulation of TREM2 processing in microglia and its potential implications for Alzheimer's disease and related dementias. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.14.544924. [PMID: 37398330 PMCID: PMC10312752 DOI: 10.1101/2023.06.14.544924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
ITM2B/BRI2 mutations cause familial forms of Alzheimer's disease (AD)-related dementias by disrupting BRI2's protein function and leading to the accumulation of amyloidogenic peptides. Although typically studied in neurons, our findings show that BRI2 is highly expressed in microglia, which are crucial in AD pathogenesis due to the association of variants in the microglial gene TREM2 with increased AD risk. Our single-cell RNAseq (scRNAseq) analysis revealed a microglia cluster that depends on a Trem2 activity that is inhibited by Bri2, pointing to a functional interaction between Itm2b/Bri2 and Trem2. Given that the AD-related Amyloid-β Precursor protein (APP) and TREM2 undergo similar proteolytic processing, and that BRI2 inhibits APP processing, we hypothesized that BRI2 may also regulate TREM2 processing. We found that BRI2 interacts with Trem2 and inhibits its processing by α-secretase in transfected cells. In mice lacking Bri2 expression, we observed increased central nervous system (CNS) levels of Trem2-CTF and sTrem2, which are the products of α-secretase processing of Trem2, indicating increased Trem2 processing by α-secretase in vivo. Reducing Bri2 expression only in microglia resulted in increased sTrem2 levels, suggesting a cell-autonomous effect of Bri2 on α-secretase processing of Trem2. Our study reveals a previously unknow role of BRI2 in regulating TREM2-related neurodegenerative mechanisms. The ability of BRI2 to regulate the processing of both APP and TREM2, combined with its cell-autonomous role in neurons and microglia, makes it a promising candidate for the development of AD and AD-related dementias therapeutics.
Collapse
Affiliation(s)
- Tao Yin
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer’s Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 205 South Orange Ave, Newark, NJ, 07103, USA
| | - Luciano D’Adamio
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer’s Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 205 South Orange Ave, Newark, NJ, 07103, USA
| |
Collapse
|
5
|
Tigro H, Shimozawa M, Nilsson P, Lyashkov A, Khadeer M, Järving I, Ferrucci L, Shimmo R, Johansson J, Moaddel R. Identification of glycolytic proteins as binding partners of Bri2 BRICHOS domain. J Pharm Biomed Anal 2023; 232:115465. [PMID: 37220701 DOI: 10.1016/j.jpba.2023.115465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 04/30/2023] [Accepted: 05/16/2023] [Indexed: 05/25/2023]
Abstract
Human integral membrane protein 2B (ITM2B or Bri2) is a member of the BRICHOS family, that can attenuate Aβ pathology in the brain. As a result, the identification of novel Bri2 BRICHOS client proteins has been sought to help elucidate signaling pathways and the potential identification of novel therapeutic targets. To identify Bri2 BRICHOS interacting partners, we carried out a 'protein fishing' experiment using recombinant human (rh) Bri2 BRICHOS-coated magnetic particles, in combination with proteomic analysis on cytosolic and membrane fractions of cortical homogenates from C57BL/6 J WT mouse. We identified 4 proteins from the cytosolic fractions and 44 proteins from the membrane fractions that had significant interactions (p < 0.05) with Bri2 BRICHOS domain, of which 11 proteins were previously identified as proteins that interacted with Bri2 BRICHOS domain. Enrichment analysis of the retained proteins identified glycolysis/gluconeogenesis as the most enriched pathway, with several proteins identified playing roles in carbon metabolism, amino acid synthesis. The data suggested that Bri2 BRICHOS may have a role in cellular energy demands in the brain via glycolysis and mitochondrial oxidative phosphorylation and may play a role in mitochondrial homeostasis.
Collapse
Affiliation(s)
- Helene Tigro
- School of Natural Sciences and Health, Tallinn University, Tallinn, Estonia; Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Makoto Shimozawa
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna, Sweden
| | - Per Nilsson
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna, Sweden
| | - Alexey Lyashkov
- Biomedical Research Centre, National Institute on Aging, NIH, Baltimore, MD 21224, United States
| | - Mohammed Khadeer
- Biomedical Research Centre, National Institute on Aging, NIH, Baltimore, MD 21224, United States
| | - Ivar Järving
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Luigi Ferrucci
- Biomedical Research Centre, National Institute on Aging, NIH, Baltimore, MD 21224, United States
| | - Ruth Shimmo
- School of Natural Sciences and Health, Tallinn University, Tallinn, Estonia
| | - Jan Johansson
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Ruin Moaddel
- Biomedical Research Centre, National Institute on Aging, NIH, Baltimore, MD 21224, United States.
| |
Collapse
|
6
|
Shimozawa M, Tigro H, Biverstål H, Shevchenko G, Bergquist J, Moaddel R, Johansson J, Nilsson P. Identification of cytoskeletal proteins as binding partners of Bri2 BRICHOS domain. Mol Cell Neurosci 2023; 125:103843. [PMID: 36935047 DOI: 10.1016/j.mcn.2023.103843] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/08/2023] [Accepted: 03/12/2023] [Indexed: 03/19/2023] Open
Abstract
Proteins must fold into three-dimensional structures to execute their biological functions. Therefore, maintenance of protein homeostasis, proteostasis, including prevention of protein misfolding is essential for cellular activity and health. Molecular chaperones are key actors in proteostasis. BRICHOS domain is an intramolecular chaperone that also interferes with several aggregation-prone proteins including amyloid β (Aβ), involved in Alzheimer's disease (AD). To extend the knowledge about Bri2 BRICHOS interactome we here used recombinant human (rh) Bri2 BRICHOS-mCherry fusion protein to probe for potential binding partners. Firstly, exogenously added Bri2 BRICHOS-mCherry was used to stain brain sections of wildtype and amyloid precursor protein (App) knock-in AD mice exhibiting robust Aβ pathology. Unexpectedly, we found that rh Bri2 BRICHOS-mCherry stained the cytoplasm of neurons which are devoid of Aβ deposits. To identify these intraneuronal proteins that bind to the rh Bri2 BRICHOS domain, we performed co-immunoprecipitation (co-IP) of mouse brain hippocampi homogenates using the Bri2 BRICHOS-mCherry probe and analyzed co-IP proteins by LC-MS/MS. This identified several cytoskeletal proteins including spectrin alpha and beta chain, drebrin, tubulin β3, and β-actin as binding partners. The interactions were confirmed by a second round of pulldown experiments using rh Bri2 BRICHOS linked to magnetic beads. The interaction of rh Bri2 BRICHOS and tubulin β3 was further investigated by staining both mouse brain sections and SH-SY5Y neuroblastoma cells with rh Bri2 BRICHOS-mCherry and tubulin β3 immunostaining, which revealed partial co-localization. These data suggest a possible interplay of extracellular chaperone Bri2 BRICHOS domain in the intracellular space including the cytoskeleton.
Collapse
Affiliation(s)
- Makoto Shimozawa
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna, Sweden.
| | - Helene Tigro
- School of Natural Sciences and Health, Tallinn University, Tallin, Estonia; Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Henrik Biverstål
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Ganna Shevchenko
- Analytical Chemistry and Neurochemistry, Department of Chemistry - Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Jonas Bergquist
- Analytical Chemistry and Neurochemistry, Department of Chemistry - Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Ruin Moaddel
- Biomedical Research Centre, National Institute on Aging, NIH, Baltimore, MD 21224, United States
| | - Jan Johansson
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Per Nilsson
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Center for Alzheimer Research, Karolinska Institutet, Solna, Sweden.
| |
Collapse
|
7
|
Martins F, Santos I, da Cruz E Silva OAB, Tambaro S, Rebelo S. The role of the integral type II transmembrane protein BRI2 in health and disease. Cell Mol Life Sci 2021; 78:6807-6822. [PMID: 34480585 PMCID: PMC11072861 DOI: 10.1007/s00018-021-03932-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/07/2021] [Accepted: 08/26/2021] [Indexed: 10/20/2022]
Abstract
BRI2 is a type II transmembrane protein ubiquitously expressed whose physiological function remains poorly understood. Although several recent important advances have substantially impacted on our understanding of BRI2 biology and function, providing valuable information for further studies on BRI2. These findings have contributed to a better understanding of BRI2 biology and the underlying signaling pathways involved. In turn, these might provide novel insights with respect to neurodegeneration processes inherent to BRI2-related pathologies, namely Familial British and Danish dementias, Alzheimer's disease, ITM2B-related retinal dystrophy, and multiple sclerosis. In this review, we provided a state-of-the-art outline of BRI2 biology, both in physiological and pathological conditions, and discuss the proposed molecular underlying mechanisms. Overall, the BRI2 knowledge here reviewed is of extreme importance and may contribute to propose BRI2 and/or BRI2 proteolytic fragments as novel therapeutic targets for neurodegenerative diseases, such as Alzheimer's disease.
Collapse
Affiliation(s)
- Filipa Martins
- Neuroscience and Signaling Laboratory, Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, 3810-193, Aveiro, Portugal.
| | - Isabela Santos
- Neuroscience and Signaling Laboratory, Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Odete A B da Cruz E Silva
- Neuroscience and Signaling Laboratory, Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, 3810-193, Aveiro, Portugal
| | - Simone Tambaro
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Karolinska Institutet, 141 83, Huddinge, Sweden.
| | - Sandra Rebelo
- Neuroscience and Signaling Laboratory, Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, 3810-193, Aveiro, Portugal.
| |
Collapse
|
8
|
A familial Danish dementia rat shows impaired presynaptic and postsynaptic glutamatergic transmission. J Biol Chem 2021; 297:101089. [PMID: 34416235 PMCID: PMC8429969 DOI: 10.1016/j.jbc.2021.101089] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/11/2021] [Accepted: 08/16/2021] [Indexed: 11/20/2022] Open
Abstract
Familial British dementia and familial Danish dementia are neurodegenerative disorders caused by mutations in the gene integral membrane protein 2B (ITM2b) encoding BRI2, which tunes excitatory synaptic transmission at both presynaptic and postsynaptic termini. In addition, BRI2 interacts with and modulates proteolytic processing of amyloid-β precursor protein (APP), whose mutations cause familial forms of Alzheimer's disease (AD) (familial AD). To study the pathogenic mechanisms triggered by the Danish mutation, we generated rats carrying the Danish mutation in the rat Itm2b gene (Itm2bD rats). Given the BRI2/APP interaction and the widely accepted relevance of human amyloid β (Aβ), a proteolytic product of APP, to AD, Itm2bD rats were engineered to express two humanized App alleles and produce human Aβ. Here, we studied young Itm2bD rats to investigate early pathogenic changes in these diseases. We found that periadolescent Itm2bD rats not only present subtle changes in human Aβ levels along with decreased spontaneous glutamate release and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor–mediated responses but also had increased short-term synaptic facilitation in the hippocampal Schaeffer-collateral pathway. These alterations in excitatory interneuronal communication can impair learning and memory processes and were akin to those observed in adult mice producing rodent Aβ and carrying either the Danish or British mutations in the mouse Itm2b gene. Collectively, the data show that the pathogenic Danish mutation alters the physiological function of BRI2 at glutamatergic synapses across species and early in life. Future studies will determine whether this phenomenon represents an early pathogenic event in human dementia.
Collapse
|
9
|
Milardi D, Gazit E, Radford SE, Xu Y, Gallardo RU, Caflisch A, Westermark GT, Westermark P, Rosa CL, Ramamoorthy A. Proteostasis of Islet Amyloid Polypeptide: A Molecular Perspective of Risk Factors and Protective Strategies for Type II Diabetes. Chem Rev 2021; 121:1845-1893. [PMID: 33427465 PMCID: PMC10317076 DOI: 10.1021/acs.chemrev.0c00981] [Citation(s) in RCA: 117] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The possible link between hIAPP accumulation and β-cell death in diabetic patients has inspired numerous studies focusing on amyloid structures and aggregation pathways of this hormone. Recent studies have reported on the importance of early oligomeric intermediates, the many roles of their interactions with lipid membrane, pH, insulin, and zinc on the mechanism of aggregation of hIAPP. The challenges posed by the transient nature of amyloid oligomers, their structural heterogeneity, and the complex nature of their interaction with lipid membranes have resulted in the development of a wide range of biophysical and chemical approaches to characterize the aggregation process. While the cellular processes and factors activating hIAPP-mediated cytotoxicity are still not clear, it has recently been suggested that its impaired turnover and cellular processing by proteasome and autophagy may contribute significantly toward toxic hIAPP accumulation and, eventually, β-cell death. Therefore, studies focusing on the restoration of hIAPP proteostasis may represent a promising arena for the design of effective therapies. In this review we discuss the current knowledge of the structures and pathology associated with hIAPP self-assembly and point out the opportunities for therapy that a detailed biochemical, biophysical, and cellular understanding of its aggregation may unveil.
Collapse
Affiliation(s)
- Danilo Milardi
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Via P. Gaifami 18, 95126 Catania, Italy
| | - Ehud Gazit
- Department of Molecular Microbiology and Biotechnology, The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Yong Xu
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Rodrigo U Gallardo
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Amedeo Caflisch
- Department of Biochemistry, University of Zürich, Zürich CH-8057, Switzerland
| | - Gunilla T Westermark
- Department of Medical Cell Biology, Uppsala University, SE-751 23 Uppsala, Sweden
| | - Per Westermark
- Department of Immunology, Genetics and Pathology, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Carmelo La Rosa
- Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Viale Andrea Doria 6, 95125 Catania, Italy
| | - Ayyalusamy Ramamoorthy
- Biophysics, Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, Michigan 41809-1055, United States
| |
Collapse
|
10
|
Cohn W, Melnik M, Huang C, Teter B, Chandra S, Zhu C, McIntire LB, John V, Gylys KH, Bilousova T. Multi-Omics Analysis of Microglial Extracellular Vesicles From Human Alzheimer's Disease Brain Tissue Reveals Disease-Associated Signatures. Front Pharmacol 2021; 12:766082. [PMID: 34925024 PMCID: PMC8675946 DOI: 10.3389/fphar.2021.766082] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 10/19/2021] [Indexed: 12/23/2022] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia, yet there is no cure or diagnostics available prior to the onset of clinical symptoms. Extracellular vesicles (EVs) are lipid bilayer-delimited particles that are released from almost all types of cell. Genome-wide association studies have linked multiple AD genetic risk factors to microglia-specific pathways. It is plausible that microglia-derived EVs may play a role in the progression of AD by contributing to the dissemination of insoluble pathogenic proteins, such as tau and Aβ. Despite the potential utility of EVs as a diagnostic tool, our knowledge of human brain EV subpopulations is limited. Here we present a method for isolating microglial CD11b-positive small EVs from cryopreserved human brain tissue, as well as an integrated multiomics analysis of microglial EVs enriched from the parietal cortex of four late-stage AD (Braak V-VI) and three age-matched normal/low pathology (NL) cases. This integrated analysis revealed 1,000 proteins, 594 lipids, and 105 miRNAs using shotgun proteomics, targeted lipidomics, and NanoString nCounter technology, respectively. The results showed a significant reduction in the abundance of homeostatic microglia markers P2RY12 and TMEM119, and increased levels of disease-associated microglia markers FTH1 and TREM2, in CD11b-positive EVs from AD brain compared to NL cases. Tau abundance was significantly higher in AD brain-derived microglial EVs. These changes were accompanied by the upregulation of synaptic and neuron-specific proteins in the AD group. Levels of free cholesterol were elevated in microglial EVs from the AD brain. Lipidomic analysis also revealed a proinflammatory lipid profile, endolysosomal dysfunction, and a significant AD-associated decrease in levels of docosahexaenoic acid (DHA)-containing polyunsaturated lipids, suggesting a potential defect in acyl-chain remodeling. Additionally, four miRNAs associated with immune and cellular senescence signaling pathways were significantly upregulated in the AD group. Our data suggest that loss of the homeostatic microglia signature in late AD stages may be accompanied by endolysosomal impairment and the release of undigested neuronal and myelin debris, including tau, through extracellular vesicles. We suggest that the analysis of microglia-derived EVs has merit for identifying novel EV-associated biomarkers and providing a framework for future larger-scale multiomics studies on patient-derived cell-type-specific EVs.
Collapse
Affiliation(s)
- Whitaker Cohn
- Drug Discovery Lab, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Mikhail Melnik
- School of Nursing, University of California, Los Angeles, Los Angeles, CA, United States
| | - Calvin Huang
- School of Nursing, University of California, Los Angeles, Los Angeles, CA, United States
| | - Bruce Teter
- Drug Discovery Lab, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Sujyoti Chandra
- Drug Discovery Lab, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Chunni Zhu
- Drug Discovery Lab, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Laura Beth McIntire
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, United States
| | - Varghese John
- Drug Discovery Lab, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Karen H Gylys
- School of Nursing, University of California, Los Angeles, Los Angeles, CA, United States
| | - Tina Bilousova
- Drug Discovery Lab, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, United States.,School of Nursing, University of California, Los Angeles, Los Angeles, CA, United States
| |
Collapse
|
11
|
Ren S, Breuillaud L, Yao W, Yin T, Norris KA, Zehntner SP, D'Adamio L. TNF-α-mediated reduction in inhibitory neurotransmission precedes sporadic Alzheimer's disease pathology in young Trem2 R47H rats. J Biol Chem 2021; 296:100089. [PMID: 33434745 PMCID: PMC7949092 DOI: 10.1074/jbc.ra120.016395] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/14/2020] [Accepted: 11/16/2020] [Indexed: 12/31/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative dementia associated with deposition of amyloid plaques and neurofibrillary tangles, formed by amyloid β (Aβ) peptides and phosphor-tau, respectively, in the central nervous system. Approximately 2% of AD cases are due to familial AD (FAD); ∼98% of cases are sporadic AD (SAD). Animal models with FAD are commonly used to study SAD pathogenesis. Because mechanisms leading to FAD and SAD may be distinct, to study SAD pathogenesis, we generated Trem2R47H knock-in rats, which carry the SAD risk factor p.R47H variant of the microglia gene triggering receptor expressed on myeloid cells 2 (TREM2). Trem2R47H rats produce human-Aβ from a humanized-App rat allele because human-Aβ is more toxic than rodent-Aβ and the pathogenic role of the p.R47H TREM2 variant has been linked to human-Aβ-clearing deficits. Using periadolescent Trem2R47H rats, we previously demonstrated that supraphysiological tumor necrosis factor-α (TNF-α) boosts glutamatergic transmission, which is excitatory, and suppresses long-term potentiation, a surrogate of learning and memory. Here, we tested the effect of the p.R47H variant on the inhibitory neurotransmitter γ-aminobutyric acid. We report that GABAergic transmission is decreased in Trem2R47H/R47H rats. This decrease is due to acute and reversible action of TNF-α and is not associated with increased human-Aβ levels and AD pathology. Thus, the p.R47H variant changes the excitatory/inhibitory balance, favoring excitation. This imbalance could potentiate glutamate excitotoxicity and contribute to neuronal dysfunction, enhanced neuronal death, and neurodegeneration. Future studies will determine whether this imbalance represents an early, Aβ-independent pathway leading to dementia and may reveal the AD-modifying therapeutic potential of TNF-α inhibition in the central nervous system.
Collapse
Affiliation(s)
- Siqiang Ren
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | | | - Wen Yao
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Tao Yin
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Kelly A Norris
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | | | - Luciano D'Adamio
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA.
| |
Collapse
|
12
|
Thorsen AS, Khamis D, Kemp R, Colombé M, Lourenço FC, Morrissey E, Winton D. Heterogeneity in clone dynamics within and adjacent to intestinal tumours identified by Dre-mediated lineage tracing. Dis Model Mech 2021; 14:dmm046706. [PMID: 33093165 PMCID: PMC7823168 DOI: 10.1242/dmm.046706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 10/12/2020] [Indexed: 11/20/2022] Open
Abstract
Somatic models of tissue pathology commonly use induction of gene-specific mutations in mice mediated by spatiotemporal regulation of Cre recombinase. Subsequent investigation of the onset and development of disease can be limited by the inability to track changing cellular behaviours over time. Here, a lineage-tracing approach based on ligand-dependent activation of Dre recombinase that can be employed independently of Cre is described. The clonal biology of the intestinal epithelium following Cre-mediated stabilisation of β-catenin reveals that, within tumours, many new clones rapidly become extinct. Surviving clones show accelerated population of tumour glands compared to normal intestinal crypts but in a non-uniform manner, indicating that intra-tumour glands follow heterogeneous dynamics. In tumour-adjacent epithelia, clone sizes are smaller than in the background epithelia, as a whole. This suggests a zone of ∼seven crypt diameters within which clone expansion is inhibited by tumours and that may facilitate their growth.
Collapse
Affiliation(s)
- Ann-Sofie Thorsen
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Doran Khamis
- University of Oxford, Center for Computational Biology, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Richard Kemp
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Mathilde Colombé
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Filipe C. Lourenço
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Edward Morrissey
- University of Oxford, Center for Computational Biology, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
| | - Douglas Winton
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| |
Collapse
|
13
|
Yin T, Yao W, Lemenze AD, D'Adamio L. Danish and British dementia ITM2b/BRI2 mutations reduce BRI2 protein stability and impair glutamatergic synaptic transmission. J Biol Chem 2020; 296:100054. [PMID: 33172889 PMCID: PMC7948410 DOI: 10.1074/jbc.ra120.015679] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 12/31/2022] Open
Abstract
Mutations in integral membrane protein 2B (ITM2b/BRI2) gene cause familial British and Danish dementia (FBD and FDD), autosomal dominant disorders characterized by progressive cognitive deterioration. Two pathogenic mechanisms, which may not be mutually exclusive, have been proposed for FDD and FBD: 1) loss of BRI2 function; 2) accumulation of amyloidogenic mutant BRI2-derived peptides, but the mechanistic details remain unclear. We have previously reported a physiological role of BRI2 in excitatory synaptic transmission at both presynaptic termini and postsynaptic termini. To test whether pathogenic ITM2b mutations affect these physiological BRI2 functions, we analyzed glutamatergic transmission in FDD and FBD knock-in mice, which carry pathogenic FDD and FBD mutations into the mouse endogenous Itm2b gene. We show that in both mutant lines, spontaneous glutamate release and AMPAR-mediated responses are decreased, while short-term synaptic facilitation is increased, effects similar to those observed in Itm2bKO mice. In vivo and in vitro studies show that both pathogenic mutations alter maturation of BRI2 resulting in reduced levels of functional mature BRI2 protein at synapses. Collectively, the data show that FDD and FBD mutations cause a reduction of BRI2 levels and function at synapses, which results in reduced glutamatergic transmission. Notably, other genes mutated in Familial dementia, such as APP, PSEN1/PSEN2, are implicated in glutamatergic synaptic transmission, a function that is altered by pathogenic mutations. Thus, defects in excitatory neurotransmitter release may represent a general and convergent mechanism leading to neurodegeneration. Targeting these dysfunction may offer a unique disease modifying method of therapeutic intervention in neurodegenerative disorders.
Collapse
Affiliation(s)
- Tao Yin
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Wen Yao
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Alexander D Lemenze
- Department of Pathology, Immunology, and Laboratory Medicine, New Jersey Medical School, The State University of New Jersey, Newark, New Jersey, USA
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology & Neuroscience, New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, New Jersey, USA.
| |
Collapse
|
14
|
Ren S, Yao W, Tambini MD, Yin T, Norris KA, D'Adamio L. Microglia TREM2R47H Alzheimer-linked variant enhances excitatory transmission and reduces LTP via increased TNF-α levels. eLife 2020; 9:57513. [PMID: 32579116 PMCID: PMC7338048 DOI: 10.7554/elife.57513] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/23/2020] [Indexed: 01/09/2023] Open
Abstract
To study the mechanisms by which the p.R47H variant of the microglia gene and Alzheimer’s disease (AD) risk factor TREM2 increases dementia risk, we created Trem2R47H KI rats. Trem2R47H rats were engineered to produce human Aβ to define human-Aβ-dependent and -independent pathogenic mechanisms triggered by this variant. Interestingly, pre- and peri-adolescent Trem2R47H rats present increased brain concentrations of TNF-α, augmented glutamatergic transmission, suppression of Long-term-Potentiation (LTP), an electrophysiological surrogate of learning and memory, but normal Aβ levels. Acute reduction of TNF-α activity with a neutralizing anti-TNF-α antibody occludes the boost in amplitude of glutamatergic transmission and LTP suppression observed in young Trem2R47H/R47H rats. Thus, the microglia-specific pathogenic Trem2 variant boosts glutamatergic neuronal transmission and suppresses LTP by increasing brain TNF-α concentrations, directly linking microglia to neuronal dysfunction. Future studies will determine whether this phenomenon represents an early, Aβ-independent pathway that facilitates dementia pathogenesis in humans.
Collapse
Affiliation(s)
- Siqiang Ren
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Wen Yao
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Marc D Tambini
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Tao Yin
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Kelly A Norris
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Newark, United States.,Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, Newark, United States
| |
Collapse
|
15
|
Poska H, Leppert A, Tigro H, Zhong X, Kaldmäe M, Nilsson HE, Hebert H, Chen G, Johansson J. Recombinant Bri3 BRICHOS domain is a molecular chaperone with effect against amyloid formation and non-fibrillar protein aggregation. Sci Rep 2020; 10:9817. [PMID: 32555390 PMCID: PMC7299998 DOI: 10.1038/s41598-020-66718-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 04/21/2020] [Indexed: 11/29/2022] Open
Abstract
Molecular chaperones assist proteins in achieving a functional structure and prevent them from misfolding into aggregates, including disease-associated deposits. The BRICHOS domain from familial dementia associated protein Bri2 (or ITM2B) probably chaperones its specific proprotein region with high β-sheet propensity during biosynthesis. Recently, Bri2 BRICHOS activity was found to extend to other amyloidogenic, fibril forming peptides, in particular, Alzheimer’s disease associated amyloid-β peptide, as well as to amorphous aggregate forming proteins. However, the biological functions of the central nervous system specific homologue Bri3 BRICHOS are still to be elucidated. Here we give a detailed characterisation of the recombinant human (rh) Bri3 BRICHOS domain and compare its structural and functional properties with rh Bri2 BRICHOS. The results show that rh Bri3 BRICHOS forms more and larger oligomers, somewhat more efficiently prevents non-fibrillar protein aggregation, and less efficiently reduces Aβ42 fibril formation compared to rh Bri2 BRICHOS. This suggests that Bri2 and Bri3 BRICHOS have overlapping molecular mechanisms and that their apparently different tissue expression and processing may result in different physiological functions.
Collapse
Affiliation(s)
- Helen Poska
- School of Natural Sciences and Health, Tallinn University, Tallinn, Estonia.,Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden
| | - Axel Leppert
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden
| | - Helene Tigro
- School of Natural Sciences and Health, Tallinn University, Tallinn, Estonia
| | - Xueying Zhong
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Margit Kaldmäe
- School of Natural Sciences and Health, Tallinn University, Tallinn, Estonia.,Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet Biomedicum, Solna, Sweden
| | - Harriet E Nilsson
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Hans Hebert
- School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Gefei Chen
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden
| | - Jan Johansson
- Department of Neurobiology, Care Sciences and Society, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden.
| |
Collapse
|
16
|
Tambini MD, D'Adamio L. Trem2 Splicing and Expression are Preserved in a Human Aβ-producing, Rat Knock-in Model of Trem2-R47H Alzheimer's Risk Variant. Sci Rep 2020; 10:4122. [PMID: 32139718 PMCID: PMC7058057 DOI: 10.1038/s41598-020-60800-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/13/2020] [Indexed: 11/18/2022] Open
Abstract
The R47H variant of the Triggering-Receptor-Expressed on Myeloid cells 2 (TREM2) increases the risk of Alzheimer's disease (AD). Mutagenesis of exon 2 in Knock-in (KI) mouse models of the R47H variant introduced a cryptic splice site, leading to nonsense mediated decay. Since haploinsufficiency does not model Trem2-R47H function, a new rat KI model, the Trem2R47H KI rat was created. Human Aβ has higher propensity to form toxic Aβ species, which are considered the main pathogenic entity in AD, as compared to rodent Aβ, the rat Amyloid Precursor Protein (App) gene was mutated to produce human Aβ. Trem2 splicing and expression was measured in Trem2R47H KI rat brains and microglia by qualitative and quantitative RT-PCR. Trem2 levels and Trem2 processing was assessed by Western analysis. APP metabolite levels were determined by enzyme-linked immunosorbent assay (ELISA), for Human Aβ and soluble APP, and Western analysis, for full length APP, βCTF and αCTF. Trem2 expression and Trem2 levels are unchanged in Trem2R47H KI rats. The artifactual splicing seen in KI mouse models is not present; additionally, two novel isoforms of rat Trem2 are described. Trem2R47H rat brains have lower human Aβ38, sAPPα and sAPPβ levels. Thus, Trem2R47H KI rats may prove valuable to define pathogenic mechanisms triggered by the Trem2 R47H variant, including those mediated by toxic species of human Aβ peptides.
Collapse
Affiliation(s)
- Marc D Tambini
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 185 South Orange Ave, Newark, NJ, 07103, USA
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 185 South Orange Ave, Newark, NJ, 07103, USA.
| |
Collapse
|
17
|
Tambini MD, Yao W, D'Adamio L. Facilitation of glutamate, but not GABA, release in Familial Alzheimer's APP mutant Knock-in rats with increased β-cleavage of APP. Aging Cell 2019; 18:e13033. [PMID: 31496118 PMCID: PMC6826143 DOI: 10.1111/acel.13033] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 08/11/2019] [Indexed: 12/01/2022] Open
Abstract
Amyloid precursor protein (APP) modulates glutamate release via cytoplasmic and intravesicular interactions with the synaptic vesicle release machinery. The intravesicular domain, called ISVAID, contains the BACE1 cleavage site of APP. We have tested the functional significance of BACE1 processing of APP using App‐Swedish (Apps) knock‐in rats, which carry an App mutation that causes familial Alzheimer's disease (FAD) in humans. We show that in Apps rats, β‐cleavage of APP is favored over α‐cleavage. Apps rats show facilitated glutamate, but not GABA, release. Our data support the notion that APP tunes glutamate release, and that BACE1 cleavage of the ISVAID segment of APP facilitates this function. We define this phenomenon as BACE1 on APP‐dependent glutamate release (BAD‐Glu). Unsurprisingly, Apps rats show no evidence of AD‐related pathology at 15 days and 3 months of age, indicating that alterations in BAD‐Glu are not caused by pathological lesions. The evidence that a pathogenic APP mutation causes an early enhancement of BAD‐Glu suggests that alterations of BACE1 processing of APP in glutamatergic synaptic vesicles could contribute to dementia.
Collapse
Affiliation(s)
- Marc D. Tambini
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School Brain Health Institute Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research Rutgers, The State University of New Jersey Newark NJ USA
| | - Wen Yao
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School Brain Health Institute Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research Rutgers, The State University of New Jersey Newark NJ USA
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School Brain Health Institute Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research Rutgers, The State University of New Jersey Newark NJ USA
| |
Collapse
|
18
|
Tuning of Glutamate, But Not GABA, Release by an Intrasynaptic Vesicle APP Domain Whose Function Can Be Modulated by β- or α-Secretase Cleavage. J Neurosci 2019; 39:6992-7005. [PMID: 31235642 DOI: 10.1523/jneurosci.0207-19.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 05/17/2019] [Accepted: 05/21/2019] [Indexed: 11/21/2022] Open
Abstract
APP, whose mutations cause familial Alzheimer's disease (FAD), modulates neurotransmission via interaction of its cytoplasmic tail with the synaptic release machinery. Here we identified an intravesicular domain of APP, called intraluminal SV-APP interacting domain (ISVAID), which interacts with glutamatergic, but not GABAergic, synaptic vesicle proteins. ISVAID contains the β- and α-secretase cleavage sites of APP: proteomic analysis of the interactome of ISVAID suggests that β- and α-secretase cleavage of APP cuts inside the interaction domain of ISVAID and destabilizes protein-protein interactions. We have tested the functional significance of the ISVAID and of β-/α-secretase-processing of APP using various ISVAID-derived peptides in competition experiments on both female and male mouse and rats hippocampal slices. A peptide encompassing the entire ISVAID facilitated glutamate, but not GABA, release acting as dominant negative inhibitor of the functions of this APP domain in acute hippocampal slices. In contrast, peptides representing the product of β-/α-secretase-processing of ISVAID did not alter excitatory neurotransmitter release. These findings suggest that cleavage of APP by either β- or α-secretase may inactivate the ISVAID, thereby enhancing glutamate release. Our present data support the notion that APP tunes glutamate release, likely through intravesicular and extravesicular interactions with synaptic vesicle proteins and the neurotransmitter release machinery, and that β-/α cleavage of APP facilitates the release of excitatory neurotransmitter.SIGNIFICANCE STATEMENT Alzheimer's disease has been linked to mutations in APP. However, the biological function of APP is poorly understood. Here we show that an intravesicular APP domain interacts with the proteins that control the release of glutamate, but not GABA. Interfering with the function of this domain promotes glutamate release. This APP domain contains the sites cleaved by β- and α-secretases: our data suggest that β-/α cleavage of APP inactivates this functional APP domain promoting excitatory neurotransmitter release.
Collapse
|
19
|
Yao W, Yin T, Tambini MD, D'Adamio L. The Familial dementia gene ITM2b/BRI2 facilitates glutamate transmission via both presynaptic and postsynaptic mechanisms. Sci Rep 2019; 9:4862. [PMID: 30890756 PMCID: PMC6425013 DOI: 10.1038/s41598-019-41340-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 03/07/2019] [Indexed: 12/12/2022] Open
Abstract
Mutations in the Integral membrane protein 2B (ITM2b/BRI2) gene, which codes for a protein called BRI2, cause familial British and Danish dementia (FBD and FDD). Loss of BRI2 function and/or accumulation of amyloidogenic mutant BRI2-derived peptides have been proposed to mediate FDD and FBD pathogenesis by impairing synaptic Long-term potentiation (LTP). However, the precise site and nature of the synaptic dysfunction remain unknown. Here we use a genetic approach to inactivate Itm2b in either presynaptic (CA3), postsynaptic (CA1) or both (CA3 + CA1) neurons of the hippocampal Schaeffer-collateral pathway in both female and male mice. We show that after CA3 + CA1 Itm2b inactivation, spontaneous glutamate release and AMPAR-mediated responses are decreased, while short-term synaptic facilitation is increased. Moreover, AMPAR-mediated responses are decreased after postsynaptic but not presynaptic deletion of Itm2b. In contrast, the probability of spontaneous glutamate release is decreased, while short-term synaptic facilitation is increased, primarily after presynaptic deletion of Itm2b. Collectively, these results indicate a dual physiological role of Itm2b in the regulation of excitatory synaptic transmission at both presynaptic termini and postsynaptic termini and suggest that presynaptic and postsynaptic dysfunctions may be a pathogenic event leading to dementia and neurodegeneration in FDD and FBD.
Collapse
Affiliation(s)
- Wen Yao
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 185 South Orange Ave, Newark, NJ, 07103, USA
| | - Tao Yin
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 185 South Orange Ave, Newark, NJ, 07103, USA
| | - Marc D Tambini
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 185 South Orange Ave, Newark, NJ, 07103, USA
| | - Luciano D'Adamio
- Department of Pharmacology, Physiology & Neuroscience New Jersey Medical School, Brain Health Institute, Jacqueline Krieger Klein Center in Alzheimer's Disease and Neurodegeneration Research, Rutgers, The State University of New Jersey, 185 South Orange Ave, Newark, NJ, 07103, USA.
| |
Collapse
|
20
|
Murray CE, Gami-Patel P, Gkanatsiou E, Brinkmalm G, Portelius E, Wirths O, Heywood W, Blennow K, Ghiso J, Holton JL, Mills K, Zetterberg H, Revesz T, Lashley T. The presubiculum is preserved from neurodegenerative changes in Alzheimer's disease. Acta Neuropathol Commun 2018; 6:62. [PMID: 30029687 PMCID: PMC6053705 DOI: 10.1186/s40478-018-0563-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 06/29/2018] [Indexed: 12/16/2022] Open
Abstract
In the majority of affected brain regions the pathological hallmarks of Alzheimer’s disease (AD) are β-amyloid (Aβ) deposits in the form of diffuse and neuritic plaques, tau pathology in the form of neurofibrillary tangles, neuropil threads and plaque-associated abnormal neurites in combination with an inflammatory response. However, the anatomical area of the presubiculum, is characterised by the presence of a single large evenly distributed ‘lake-like’ Aβ deposit with minimal tau deposition or accumulation of inflammatory markers. Post-mortem brain samples from sporadic AD (SAD) and familial AD (FAD) and two hereditary cerebral amyloid diseases, familial British dementia (FBD) and familial Danish dementia (FDD) were used to compare the morphology of the extracellular proteins deposited in the presubiculum compared to the entorhinal cortex. The level of tau pathology and the extent of microglial activation were quantitated in the two brain regions in SAD and FAD. Frozen tissue was used to investigate the Aβ species and proteomic differences between the two regions. Consistent with our previous investigations of FBD and FDD cases we were able to establish that the ‘lake-like’ pre-amyloid deposits of the presubiculum were not a unique feature of AD but they also found two non-Aβ amyloidosis. Comparing the presubiculum to the entorhinal cortex the number of neurofibrillary tangles and tau load were significantly reduced; there was a reduction in microglial activation; there were differences in the Aβ profiles and the investigation of the whole proteome showed significant changes in different protein pathways. In summary, understanding why the presubiculum has a different morphological appearance, biochemical and proteomic makeup compared to surrounding brain regions severely affected by neurodegeneration could lead us to understanding protective mechanisms in neurodegenerative diseases.
Collapse
|
21
|
Matsuda S, Senda T. BRI2 as an anti-Alzheimer gene. Med Mol Morphol 2018; 52:1-7. [DOI: 10.1007/s00795-018-0191-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 04/18/2018] [Indexed: 12/16/2022]
|
22
|
BRICHOS domain of Bri2 inhibits islet amyloid polypeptide (IAPP) fibril formation and toxicity in human beta cells. Proc Natl Acad Sci U S A 2018; 115:E2752-E2761. [PMID: 29507232 PMCID: PMC5866560 DOI: 10.1073/pnas.1715951115] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Accumulation of islet amyloid polypeptide (IAPP)-containing amyloid fibrils is the main pathological finding in pancreatic islets in type 2 diabetes. The formation of these IAPP amyloid fibrils is considered toxic and may constitute a major cause for the loss of insulin-producing beta cells. The protein domain BRICHOS is present in several different proproteins and possesses antiamyloid chaperone activity. This study demonstrates expression of the BRICHOS-containing protein Bri2 in human pancreatic beta cells and its colocalization with IAPP. The Bri2 BRICHOS domain effectively prevents IAPP from forming fibrils and protects cells from the toxicity associated with IAPP fibrillation. It is concluded that the Bri2 BRICHOS domain may act as an endogenous inhibitor of IAPP amyloid formation in pancreatic beta cells. Aggregation of islet amyloid polypeptide (IAPP) into amyloid fibrils in islets of Langerhans is associated with type 2 diabetes, and formation of toxic IAPP species is believed to contribute to the loss of insulin-producing beta cells. The BRICHOS domain of integral membrane protein 2B (Bri2), a transmembrane protein expressed in several peripheral tissues and in the brain, has recently been shown to prevent fibril formation and toxicity of Aβ42, an amyloid-forming peptide in Alzheimer disease. In this study, we demonstrate expression of Bri2 in human islets and in the human beta-cell line EndoC-βH1. Bri2 colocalizes with IAPP intracellularly and is present in amyloid deposits in patients with type 2 diabetes. The BRICHOS domain of Bri2 effectively inhibits fibril formation in vitro and instead redirects IAPP into formation of amorphous aggregates. Reduction of endogenous Bri2 in EndoC-βH1 cells with siRNA increases sensitivity to metabolic stress leading to cell death while a concomitant overexpression of Bri2 BRICHOS is protective. Also, coexpression of IAPP and Bri2 BRICHOS in lateral ventral neurons of Drosophila melanogaster results in an increased cell survival. IAPP is considered to be the most amyloidogenic peptide known, and described findings identify Bri2, or in particular its BRICHOS domain, as an important potential endogenous inhibitor of IAPP aggregation and toxicity, with the potential to be a possible target for the treatment of type 2 diabetes.
Collapse
|
23
|
Dolfe L, Tambaro S, Tigro H, Del Campo M, Hoozemans JJM, Wiehager B, Graff C, Winblad B, Ankarcrona M, Kaldmäe M, Teunissen CE, Rönnbäck A, Johansson J, Presto J. The Bri2 and Bri3 BRICHOS Domains Interact Differently with Aβ 42 and Alzheimer Amyloid Plaques. J Alzheimers Dis Rep 2018; 2:27-39. [PMID: 30480246 PMCID: PMC6159705 DOI: 10.3233/adr-170051] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia and there is no successful treatment available. Evidence suggests that fibril formation of the amyloid β-peptide (Aβ) is a major underlying cause of AD, and treatment strategies that reduce the toxic effects of Aβ amyloid are sought for. The BRICHOS domain is found in several proteins, including Bri2 (also called integral membrane protein 2B (ITM2B)), mutants of which are associated with amyloid and neurodegeneration, and Bri3 (ITM2C). We have used mouse hippocampal neurons and brain tissues from mice and humans and show Bri3 deposits dispersed on AD plaques. In contrast to what has been shown for Bri2, Bri3 immunoreactivity is decreased in AD brain homogenates compared to controls. Both Bri2 and Bri3 BRICHOS domains interact with Aβ40 and Aβ42 present in neurons and reduce Aβ42 amyloid fibril formation in vitro, but Bri3 BRICHOS is less efficient. These results indicate that Bri2 and Bri3 BRICHOS have different roles in relation to Aβ aggregation.
Collapse
Affiliation(s)
- Lisa Dolfe
- Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden
| | - Simone Tambaro
- Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden
| | - Helene Tigro
- School of Natural Sciences and Health, Tallinn University, Tallinn, Estonia
| | - Marta Del Campo
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Jeroen J M Hoozemans
- Neurochemistry Lab, Department of Clinical Chemistry, Amsterdam Neuroscience, VU University Medical Center, The Netherlands
| | - Birgitta Wiehager
- Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden
| | - Caroline Graff
- Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden.,Genetic Unit, Theme Aging, Karolinska University Hospital, Sweden
| | - Bengt Winblad
- Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden
| | - Maria Ankarcrona
- Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden
| | - Margit Kaldmäe
- School of Natural Sciences and Health, Tallinn University, Tallinn, Estonia
| | - Charlotte E Teunissen
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Annica Rönnbäck
- Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden
| | - Jan Johansson
- Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden.,School of Natural Sciences and Health, Tallinn University, Tallinn, Estonia
| | - Jenny Presto
- Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, Huddinge, Sweden
| |
Collapse
|
24
|
Expression Pattern of the BCL6 and ITM2B Proteins in Normal Human Brains and in Alzheimer Disease. Appl Immunohistochem Mol Morphol 2018; 25:489-496. [PMID: 26862951 DOI: 10.1097/pai.0000000000000329] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We reported that the integral membrane 2B gene (ITM2B, also called BRI2) is a target of BCL6 repression in lymphomas. Molecular alterations in ITM2B are associated with 2 neurodegenerative diseases, Familial British and Danish dementia, and dysregulation of ITM2B function has been implicated in the pathogenesis of Alzheimer disease (AD). Although ITM2B expression has been studied, the distribution of BCL6 in human brain has not been described. Our goal is to analyze BCL6 and ITM2B localization in normal human brains and in AD by immunohistochemistry to understand their relationship. We found that, in general, they have a reciprocal relationship. BCL6 expression is present in isolated cortical neurons, granule cells in the cerebellum, scattered glial cells, and in some cells of the ependyma and choroid plexus. ITM2B is expressed in most cortical neurons, neurons of the hippocampus and dentate nucleus, cerebellar Purkinje and granule cells, and (newly described here) in focal neurons in the basal ganglia, many neurons of the thalamus and brainstem, many cells in the ependyma and choroid plexus, and in the smooth muscle of blood vessels. ITM2B expression is prominent in plaques in AD-containing dystrophic neurites but absent in neurofibrillary tangles; BCL6 expression is absent in neurofibrillary tangles and in the nuclei of cells associated with plaques in AD. It is essential to understand the localization of BCL6 and ITM2B in the brain before considering manipulation of their expression as a potential therapeutic tool.
Collapse
|
25
|
Deletion of the γ-secretase subunits Aph1B/C impairs memory and worsens the deficits of knock-in mice modeling the Alzheimer-like familial Danish dementia. Oncotarget 2017; 7:11923-44. [PMID: 26942869 PMCID: PMC4914259 DOI: 10.18632/oncotarget.7389] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/08/2016] [Indexed: 12/26/2022] Open
Abstract
Mutations in BRI2/ITM2b genes cause Familial British and Danish Dementias (FBD and FDD), which are pathogenically similar to Familial Alzheimer Disease (FAD). BRI2 inhibits processing of Amyloid precursor protein (APP), a protein involved in FAD pathogenesis. Accumulation of a carboxyl-terminal APP metabolite -ß-CTF- causes memory deficits in a knock-in mouse model of FDD, called FDDKI.We have investigated further the pathogenic function of ß-CTF studying the effect of Aph1B/C deletion on FDDKI mice. This strategy is based on the evidence that deletion of Aph1B/C proteins, which are components of the γ-secretase that cleaves ß-CTF, results in stabilization of ß-CTF and a reduction of Aβ. We found that both the FDD mutation and the Aph1B/C deficiency mildly interfered with spatial long term memory, spatial working/short-term memory and long-term contextual fear memory. In addition, the Aph1BC deficiency induced deficits in long-term cued fear memory. Moreover, the two mutations have additive adverse effects as they compromise the accuracy of spatial long-term memory and induce spatial memory retention deficits in young mice. Overall, the data are consistent with a role for β-CTF in the genesis of memory deficits.
Collapse
|
26
|
Li X, Song Y, Sanders CR, Buxbaum JN. Transthyretin Suppresses Amyloid-β Secretion by Interfering with Processing of the Amyloid-β Protein Precursor. J Alzheimers Dis 2017; 52:1263-75. [PMID: 27079720 DOI: 10.3233/jad-160033] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In Alzheimer's disease (AD), most hippocampal and cortical neurons show increased staining with anti-transthyretin (TTR) antibodies. Genetically programmed overexpression of wild type human TTR suppressed the neuropathologic and behavioral abnormalities in APP23 AD model mice and TTR-Aβ complexes have been isolated from some human AD brains and those of APP23 transgenic mice. In the present study, in vitro NMR analysis showed interaction between the hydrophobic thyroxine binding pocket of TTR and the cytoplasmic loop of the C99 fragment released by β-secretase cleavage of AβPP, with Kd = 86±9 μM. In cultured cells expressing both proteins, the interaction reduced phosphorylation of C99 (at T668) and suppressed its cleavage by γ-secretase, significantly decreasing Aβ secretion. Coupled with its previously demonstrated capacity to inhibit Aβ aggregation (with the resultant cytotoxicity in tissue culture) and its regulation by HSF1, these findings indicate that TTR can behave as a stress responsive multimodal suppressor of AD pathogenesis.
Collapse
Affiliation(s)
- Xinyi Li
- Janssen Research & Development, LLC, Johnson & Johnson, San Diego, CA, USA.,Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Yuanli Song
- Bristol-Myers Squibb, Biologics Process Development, Devens, MA, USA.,Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Charles R Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Joel N Buxbaum
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| |
Collapse
|
27
|
Abolishing Tau cleavage by caspases at Aspartate 421 causes memory/synaptic plasticity deficits and pre-pathological Tau alterations. Transl Psychiatry 2017; 7:e1198. [PMID: 28786980 PMCID: PMC5611732 DOI: 10.1038/tp.2017.165] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 05/30/2017] [Accepted: 06/07/2017] [Indexed: 01/03/2023] Open
Abstract
TAU mutations are genetically linked to fronto-temporal dementia (FTD) and hyper-phosphorylated aggregates of Tau form neurofibrillary tangles (NFTs) that constitute a pathological hallmark of Alzheimer disease (AD) and FTD. These observations indicate that Tau has a pivotal role in the pathogenesis of neurodegenerative disorders. Tau is cleaved by caspases at Aspartate421, to form a Tau metabolite known as δTau; δTau is increased in AD, due to the hyper-activation of caspases in AD brains. δTau is considered a critical toxic moiety underlying neurodegeneration, which initiates and facilitates NFT formation. As Tau is a therapeutic target in neurodegeneration, it is important to rigorously determine whether δTau is a toxic Tau species that should be pharmacologically attacked. To directly address these questions, we have generated a knock-in (KI) mouse called TauDN-that expresses a Tau mutant that cannot be cleaved by caspases. TauDN mice present short-term memory deficits and synaptic plasticity defects. Moreover, mice carrying two mutant Tau alleles show increased total insoluble hyper-phosphorylated Tau in the forebrain. These data are in contrast with the concept that δTau is a critical toxic moiety underlying neurodegeneration, and suggest that cleavage of Tau by caspases represents a negative feedback mechanism aimed to eliminate toxic Tau species. Alternatively, it is possible that either a reduction or an increase in δTau leads to synaptic dysfunction, memory impairments and Tau pathology. Both possibilities will have to be considered when targeting caspase cleavage of Tau in AD therapy.
Collapse
|
28
|
Buxbaum JN, Johansson J. Transthyretin and BRICHOS: The Paradox of Amyloidogenic Proteins with Anti-Amyloidogenic Activity for Aβ in the Central Nervous System. Front Neurosci 2017; 11:119. [PMID: 28360830 PMCID: PMC5350149 DOI: 10.3389/fnins.2017.00119] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 02/27/2017] [Indexed: 01/19/2023] Open
Abstract
Amyloid fibrils are physiologically insoluble biophysically specific β-sheet rich structures formed by the aggregation of misfolded proteins. In vivo tissue amyloid formation is responsible for more than 30 different disease states in humans and other mammals. One of these, Alzheimer's disease (AD), is the most common form of human dementia for which there is currently no definitive treatment. Amyloid fibril formation by the amyloid β-peptide (Aβ) is considered to be an underlying cause of AD, and strategies designed to reduce Aβ production and/or its toxic effects are being extensively investigated in both laboratory and clinical settings. Transthyretin (TTR) and proteins containing a BRICHOS domain are etiologically associated with specific amyloid diseases in the CNS and other organs. Nonetheless, it has been observed that TTR and BRICHOS structures are efficient inhibitors of Aβ fibril formation and toxicity in vitro and in vivo, raising the possibility that some amyloidogenic proteins, or their precursors, possess properties that may be harnessed for combating AD and other amyloidoses. Herein, we review properties of TTR and the BRICHOS domain and discuss how their abilities to interfere with amyloid formation may be employed in the development of novel treatments for AD.
Collapse
Affiliation(s)
- Joel N Buxbaum
- Department of Molecular and Experimental Medicine, The Scripps Research InstituteLa Jolla, CA, USA; Scintillon InstituteSan Diego, CA, USA
| | - Jan Johansson
- Division of Neurogeriatrics, Department of Neurobiology, Care Sciences, and Society (NVS), Center for Alzheimer Research, Karolinska Institutet Huddinge, Sweden
| |
Collapse
|
29
|
Di Stadio CS, Altieri F, Minopoli G, Miselli G, Rippa E, Arcari P. Role of human GKN1 on APP processing in gastric cancer. Biochimie 2017; 135:149-153. [PMID: 28214529 DOI: 10.1016/j.biochi.2017.02.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 02/13/2017] [Indexed: 12/16/2022]
Abstract
Gastrokine 1 (GKN1) is highly expressed in gastric tissue and is secreted into the stomach but is not expressed in gastric cancer. GKN1 belongs to the BRICHOS domain family and plays a major role in maintaining gastric mucosa integrity. We previously demonstrated that a recombinant human GKN1 protein was able to interact with the amyloid precursor protein (APP) and was endowed with an anti-amyloidogenic property because it inhibited polymerization of the Aβ(1-40) peptide released from APP upon its partial hydrolysis. Here, we report that GKN1 can act as a physiological suppressor of Aβ production in gastric cancer cells. GKN1 blocked the access of γ-secretase to APP, thereby facilitating the cleavage of APP by α- and β-secretases. GKN1 directly interacted with APP C-terminal fragments, C83 and C99. In addition, it did not affect γ-secretase activity in gastric cancer cells because it did not alter Notch1 processing. GKN1-mediated inhibition of APP processing might represent a new approach for the prevention and therapy of Alzheimer's disease (AD).
Collapse
Affiliation(s)
- Chiara Stella Di Stadio
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Filomena Altieri
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Giuseppina Minopoli
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Giuseppina Miselli
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Emilia Rippa
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy.
| | - Paolo Arcari
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy; CEINGE, Advanced Biotechnology Scarl, Via Gaetano Salvatore 486, I-80145, Naples, Italy.
| |
Collapse
|
30
|
Garringer HJ, Sammeta N, Oblak A, Ghetti B, Vidal R. Amyloid and intracellular accumulation of BRI 2. Neurobiol Aging 2016; 52:90-97. [PMID: 28131015 DOI: 10.1016/j.neurobiolaging.2016.12.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 11/29/2016] [Accepted: 12/18/2016] [Indexed: 01/07/2023]
Abstract
Familial British dementia (FBD) and familial Danish dementia (FDD) are caused by mutations in the BRI2 gene. These diseases are characterized clinically by progressive dementia and ataxia and neuropathologically by amyloid deposits and neurofibrillary tangles. Herein, we investigate BRI2 protein accumulation in FBD, FDD, Alzheimer disease and Gerstmann-Sträussler-Scheinker disease. In FBD and FDD, we observed reduced processing of the mutant BRI2 pro-protein, which was found accumulating intracellularly in the Golgi of neurons and glial cells. In addition, we observed an accumulation of a mature form of BRI2 protein in dystrophic neurites, surrounding amyloid cores. Accumulation of BRI2 was also observed in dystrophic neurites of Alzheimer disease and Gerstmann-Sträussler-Scheinker disease cases. Although it remains to be determined whether intracellular accumulation of BRI2 may lead to cell damage in these degenerative diseases, our study provides new insights into the role of mutant BRI2 in the pathogenesis of FBD and FDD and implicates BRI2 as a potential indicator of neuritic damage in diseases characterized by cerebral amyloid deposition.
Collapse
Affiliation(s)
- Holly J Garringer
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Neeraja Sammeta
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Adrian Oblak
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Bernardino Ghetti
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ruben Vidal
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA.
| |
Collapse
|
31
|
Schröder B, Saftig P. Intramembrane proteolysis within lysosomes. Ageing Res Rev 2016; 32:51-64. [PMID: 27143694 DOI: 10.1016/j.arr.2016.04.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/01/2016] [Accepted: 04/26/2016] [Indexed: 11/26/2022]
Abstract
Regulated intramembrane proteolysis is of pivotal importance in a diverse set of developmental and physiological processes. Altered intramembrane substrate turnover may be associated with neurodegeneration, cancer and impaired immune function. In this review we will focus on the intramembrane proteases which have been localized in the lysosomal membrane. Members of the γ-secretase complex and γ-secretase activity are found in the lysosomal membrane and are discussed to contribute to intracellular amyloid β production. Mutant or deficient γ-secretase may cause disturbed lysosomal function. The signal peptide peptidase-like (SPPL) protease 2a is a lysosomal membrane component and cleaves CD74, the invariant chain of the MHC II complex, as well as FasL, TNF, ITM2B and TMEM106, type II transmembrane proteins involved in the regulation of immunity and neurodegeneration. Therefore, it can be concluded, that not only proteolysis within the lysosomal lumen but also within lysosomal membranes regulates important cellular functions and contributes essentially to proteostasis of membrane proteins what may become increasingly compromised in the aged individual.
Collapse
|
32
|
Domanski D, Zegrocka-Stendel O, Perzanowska A, Dutkiewicz M, Kowalewska M, Grabowska I, Maciejko D, Fogtman A, Dadlez M, Koziak K. Molecular Mechanism for Cellular Response to β-Escin and Its Therapeutic Implications. PLoS One 2016; 11:e0164365. [PMID: 27727329 PMCID: PMC5058498 DOI: 10.1371/journal.pone.0164365] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 09/23/2016] [Indexed: 11/18/2022] Open
Abstract
β-escin is a mixture of triterpene saponins isolated from the horse chestnut seeds (Aesculus hippocastanum L.). The anti-edematous, anti-inflammatory and venotonic properties of β-escin have been the most extensively clinically investigated effects of this plant-based drug and randomized controlled trials have proved the efficacy of β-escin for the treatment of chronic venous insufficiency. However, despite the clinical recognition of the drug its pharmacological mechanism of action still remains largely elusive. To determine the cellular and molecular basis for the therapeutic effectiveness of β-escin we performed discovery and targeted proteomic analyses and in vitro evaluation of cellular and molecular responses in human endothelial cells under inflammatory conditions. Our results demonstrate that in endothelial cells β-escin potently induces cholesterol synthesis which is rapidly followed with marked fall in actin cytoskeleton integrity. The concomitant changes in cell functioning result in a significantly diminished responses to TNF-α stimulation. These include reduced migration, alleviated endothelial monolayer permeability, and inhibition of NFκB signal transduction leading to down-expression of TNF-α-induced effector proteins. Moreover, the study provides evidence for novel therapeutic potential of β-escin beyond the current vascular indications.
Collapse
Affiliation(s)
- Dominik Domanski
- Laboratory of Mass Spectrometry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Oliwia Zegrocka-Stendel
- Centre for Preclinical Research and Technology, Department of Immunology, Biochemistry and Nutrition, Medical University of Warsaw, Warsaw, Poland
| | - Anna Perzanowska
- Laboratory of Mass Spectrometry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Malgorzata Dutkiewicz
- Centre for Preclinical Research and Technology, Department of Immunology, Biochemistry and Nutrition, Medical University of Warsaw, Warsaw, Poland
| | - Magdalena Kowalewska
- Department of Molecular and Translational Oncology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
| | - Iwona Grabowska
- Department of Cytology, Faculty of Biology, University of Warsaw, Warsaw, Miecznikowa 1, 02–096 Warsaw, Poland
| | - Dorota Maciejko
- Centre for Preclinical Research and Technology, Department of Immunology, Biochemistry and Nutrition, Medical University of Warsaw, Warsaw, Poland
| | - Anna Fogtman
- Laboratory for Microarray Analysis CORELAB, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Michal Dadlez
- Laboratory of Mass Spectrometry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Koziak
- Centre for Preclinical Research and Technology, Department of Immunology, Biochemistry and Nutrition, Medical University of Warsaw, Warsaw, Poland
| |
Collapse
|
33
|
Dementia-related Bri2 BRICHOS is a versatile molecular chaperone that efficiently inhibits Aβ42 toxicity in Drosophila. Biochem J 2016; 473:3683-3704. [PMID: 27514716 DOI: 10.1042/bcj20160277] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 08/11/2016] [Indexed: 11/17/2022]
Abstract
Formation of fibrils of the amyloid-β peptide (Aβ) is suggested to play a central role in neurodegeneration in Alzheimer's disease (AD), for which no effective treatment exists. The BRICHOS domain is a part of several disease-related proproteins, the most studied ones being Bri2 associated with familial dementia and prosurfactant protein C (proSP-C) associated with lung amyloid. BRICHOS from proSP-C has been found to be an efficient inhibitor of Aβ aggregation and toxicity, but its lung-specific expression makes it unsuited to target in AD. Bri2 is expressed in the brain, affects processing of Aβ precursor protein, and increased levels of Bri2 are found in AD brain, but the specific role of its BRICHOS domain has not been studied in vivo Here, we find that transgenic expression of the Bri2 BRICHOS domain in the Drosophila central nervous system (CNS) or eyes efficiently inhibits Aβ42 toxicity. In the presence of Bri2 BRICHOS, Aβ42 is diffusely distributed throughout the mushroom bodies, a brain region involved in learning and memory, whereas Aβ42 expressed alone or together with proSP-C BRICHOS forms punctuate deposits outside the mushroom bodies. Recombinant Bri2 BRICHOS domain efficiently prevents Aβ42-induced reduction in γ-oscillations in hippocampal slices. Finally, Bri2 BRICHOS inhibits several steps in the Aβ42 fibrillation pathway and prevents aggregation of heat-denatured proteins, indicating that it is a more versatile chaperone than proSP-C BRICHOS. These findings suggest that Bri2 BRICHOS can be a physiologically relevant chaperone for Aβ in the CNS and needs to be further investigated for its potential in AD treatment.
Collapse
|
34
|
Andrew RJ, Kellett KAB, Thinakaran G, Hooper NM. A Greek Tragedy: The Growing Complexity of Alzheimer Amyloid Precursor Protein Proteolysis. J Biol Chem 2016; 291:19235-44. [PMID: 27474742 DOI: 10.1074/jbc.r116.746032] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Proteolysis of the amyloid precursor protein (APP) liberates various fragments including the proposed initiator of Alzheimer disease-associated dysfunctions, amyloid-β. However, recent evidence suggests that the accepted view of APP proteolysis by the canonical α-, β-, and γ-secretases is simplistic, with the discovery of a number of novel APP secretases (including δ- and η-secretases, alternative β-secretases) and additional metabolites, some of which may also cause synaptic dysfunction. Furthermore, various proteins have been identified that interact with APP and modulate its cleavage by the secretases. Here, we give an overview of the increasingly complex picture of APP proteolysis.
Collapse
Affiliation(s)
- Robert J Andrew
- From the Departments of Neurobiology, Neurology, and Pathology, The University of Chicago, Chicago, Illinois 60637 and
| | - Katherine A B Kellett
- the Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Gopal Thinakaran
- From the Departments of Neurobiology, Neurology, and Pathology, The University of Chicago, Chicago, Illinois 60637 and
| | - Nigel M Hooper
- the Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom
| |
Collapse
|
35
|
Alzheimer disease: modeling an Aβ-centered biological network. Mol Psychiatry 2016; 21:861-71. [PMID: 27021818 DOI: 10.1038/mp.2016.38] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/16/2016] [Accepted: 02/18/2016] [Indexed: 01/15/2023]
Abstract
In genetically complex diseases, the search for missing heritability is focusing on rare variants with large effect. Thanks to next generation sequencing technologies, genome-wide characterization of these variants is now feasible in every individual. However, a lesson from current studies is that collapsing rare variants at the gene level is often insufficient to obtain a statistically significant signal in case-control studies, and that network-based analyses are an attractive complement to classical approaches. In Alzheimer disease (AD), according to the prevalent amyloid cascade hypothesis, the pathology is driven by the amyloid beta (Aβ) peptide. In past years, based on experimental studies, several hundreds of proteins have been shown to interfere with Aβ production, clearance, aggregation or toxicity. Thanks to a manual curation of the literature, we identified 335 genes/proteins involved in this biological network and classified them according to their cellular function. The complete list of genes, or its subcomponents, will be of interest in ongoing AD genetic studies.
Collapse
|
36
|
Del Prete D, Rice RC, Rajadhyaksha AM, D'Adamio L. Amyloid Precursor Protein (APP) May Act as a Substrate and a Recognition Unit for CRL4CRBN and Stub1 E3 Ligases Facilitating Ubiquitination of Proteins Involved in Presynaptic Functions and Neurodegeneration. J Biol Chem 2016; 291:17209-27. [PMID: 27325702 DOI: 10.1074/jbc.m116.733626] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Indexed: 12/23/2022] Open
Abstract
The amyloid precursor protein (APP), whose mutations cause Alzheimer disease, plays an important in vivo role and facilitates transmitter release. Because the APP cytosolic region (ACR) is essential for these functions, we have characterized its brain interactome. We found that the ACR interacts with proteins that regulate the ubiquitin-proteasome system, predominantly with the E3 ubiquitin-protein ligases Stub1, which binds the NH2 terminus of the ACR, and CRL4(CRBN), which is formed by Cul4a/b, Ddb1, and Crbn, and interacts with the COOH terminus of the ACR via Crbn. APP shares essential functions with APP-like protein-2 (APLP2) but not APP-like protein-1 (APLP1). Noteworthy, APLP2, but not APLP1, interacts with Stub1 and CRL4(CRBN), pointing to a functional pathway shared only by APP and APLP2. In vitro ubiquitination/ubiquitome analysis indicates that these E3 ligases are enzymatically active and ubiquitinate the ACR residues Lys(649/650/651/676/688) Deletion of Crbn reduces ubiquitination of Lys(676) suggesting that Lys(676) is physiologically ubiquitinated by CRL4(CRBN) The ACR facilitated in vitro ubiquitination of presynaptic proteins that regulate exocytosis, suggesting a mechanism by which APP tunes transmitter release. Other dementia-related proteins, namely Tau and apoE, interact with and are ubiquitinated via the ACR in vitro This, and the evidence that CRBN and CUL4B are linked to intellectual disability, prompts us to hypothesize a pathogenic mechanism, in which APP acts as a modulator of E3 ubiquitin-protein ligase(s), shared by distinct neuronal disorders. The well described accumulation of ubiquitinated protein inclusions in neurodegenerative diseases and the link between the ubiquitin-proteasome system and neurodegeneration make this concept plausible.
Collapse
Affiliation(s)
- Dolores Del Prete
- From the Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461 and
| | - Richard C Rice
- the Division of Pediatric Neurology, Department of Pediatrics, and
| | - Anjali M Rajadhyaksha
- the Division of Pediatric Neurology, Department of Pediatrics, and Feil Family Brain and Mind Research Institute, Weill Cornell Autism Research Program, Weill Cornell Medical College, New York, New York 10065
| | - Luciano D'Adamio
- From the Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461 and
| |
Collapse
|
37
|
APP Receptor? To Be or Not To Be. Trends Pharmacol Sci 2016; 37:390-411. [PMID: 26837733 DOI: 10.1016/j.tips.2016.01.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/07/2016] [Accepted: 01/11/2016] [Indexed: 11/22/2022]
Abstract
Amyloid precursor protein (APP) and its metabolites play a key role in Alzheimer's disease pathogenesis. The idea that APP may function as a receptor has gained momentum based on its structural similarities to type I transmembrane receptors and the identification of putative APP ligands. We review the recent experimental evidence in support of this notion and discuss how this concept is viewed in the field. Specifically, we focus on the structural and functional characteristics of APP as a cell surface receptor, and on its interaction with adaptors and signaling proteins. We also address the importance of APP function as a receptor in Alzheimer's disease etiology and discuss how this function might be potentially important for the development of novel therapeutic approaches.
Collapse
|
38
|
Fanutza T, Del Prete D, Ford MJ, Castillo PE, D’Adamio L. APP and APLP2 interact with the synaptic release machinery and facilitate transmitter release at hippocampal synapses. eLife 2015; 4:e09743. [PMID: 26551565 PMCID: PMC4755753 DOI: 10.7554/elife.09743] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 11/08/2015] [Indexed: 12/16/2022] Open
Abstract
The amyloid precursor protein (APP), whose mutations cause familial Alzheimer's disease, interacts with the synaptic release machinery, suggesting a role in neurotransmission. Here we mapped this interaction to the NH2-terminal region of the APP intracellular domain. A peptide encompassing this binding domain -named JCasp- is naturally produced by a γ-secretase/caspase double-cut of APP. JCasp interferes with the APP-presynaptic proteins interaction and, if linked to a cell-penetrating peptide, reduces glutamate release in acute hippocampal slices from wild-type but not APP deficient mice, indicating that JCasp inhibits APP function.The APP-like protein-2 (APLP2) also binds the synaptic release machinery. Deletion of APP and APLP2 produces synaptic deficits similar to those caused by JCasp. Our data support the notion that APP and APLP2 facilitate transmitter release, likely through the interaction with the neurotransmitter release machinery. Given the link of APP to Alzheimer's disease, alterations of this synaptic role of APP could contribute to dementia.
Collapse
Affiliation(s)
- Tomas Fanutza
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, United States
| | - Dolores Del Prete
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, United States
| | | | - Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, United States
| | - Luciano D’Adamio
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, United States
| |
Collapse
|
39
|
Biundo F, Ishiwari K, Del Prete D, D'Adamio L. Interaction of ApoE3 and ApoE4 isoforms with an ITM2b/BRI2 mutation linked to the Alzheimer disease-like Danish dementia: Effects on learning and memory. Neurobiol Learn Mem 2015; 126:18-30. [PMID: 26528887 DOI: 10.1016/j.nlm.2015.10.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 10/09/2015] [Accepted: 10/15/2015] [Indexed: 12/30/2022]
Abstract
Mutations in Amyloid β Precursor Protein (APP) and in genes that regulate APP processing--such as PSEN1/2 and ITM2b/BRI2--cause familial dementia, such Familial Alzheimer disease (FAD), Familial Danish (FDD) and British (FBD) dementias. The ApoE gene is the major genetic risk factor for sporadic AD. Three major variants of ApoE exist in humans (ApoE2, ApoE3, and ApoE4), with the ApoE4 allele being strongly associated with AD. ITM2b/BRI2 is also a candidate regulatory node genes predicted to mediate the common patterns of gene expression shared by healthy ApoE4 carriers and late-onset AD patients not carrying ApoE4. This evidence provides a direct link between ITM2b/BRI2 and ApoE4. To test whether ApoE4 and pathogenic ITM2b/BRI2 interact to modulate learning and memory, we crossed a mouse carrying the ITM2b/BRI2 mutations that causes FDD knocked-in the endogenous mouse Itm2b/Bri2 gene (FDDKI mice) with human ApoE3 and ApoE4 targeted replacement mice. The resultant ApoE3, FDDKI/ApoE3, ApoE4, FDDKI/ApoE4 male mice were assessed longitudinally for learning and memory at 4, 6, 12, and 16-17 months of age. The results showed that ApoE4-carrying mice displayed spatial working/short-term memory deficits relative to ApoE3-carrying mice starting in early middle age, while long-term spatial memory of ApoE4 mice was not adversely affected even at 16-17 months, and that the FDD mutation impaired working/short-term spatial memory in ApoE3-carrying mice and produced impaired long-term spatial memory in ApoE4-carrying mice in middle age. The present results suggest that the FDD mutation may differentially affect learning and memory in ApoE4 carriers and non-carriers.
Collapse
Affiliation(s)
- Fabrizio Biundo
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Keita Ishiwari
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Dolores Del Prete
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Luciano D'Adamio
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, United States.
| |
Collapse
|
40
|
Martins F, Rebelo S, Santos M, Cotrim CZ, da Cruz e Silva EF, da Cruz e Silva OAB. BRI2 and BRI3 are functionally distinct phosphoproteins. Cell Signal 2015; 28:130-44. [PMID: 26515131 DOI: 10.1016/j.cellsig.2015.10.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/24/2015] [Indexed: 01/21/2023]
Abstract
Three BRI protein family members have been identified. Among these are BRI3 and BRI2, the latter is associated with Familial Danish and Familial British dementias. 'In silico' sequence analysis identified putative PP1 binding sites in BRI2 and BRI3. This is singularly important, given that protein phosphorylation is a major mechanism regulating intracellular processes. Protein phosphatase 1 (PP1) interacting proteins (PIPs) are fundamental in determining substrate specificity and subcellular localization of this phosphatase. More than 200 PIPs have thus far been reported. Both BRI2 and BRI3 are type II transmembrane glycoproteins relevant in neuronal systems. Using Myc-BRI2 and Myc-BRI3, wild type and PP1 binding mutant constructs, it was possible to show, for the first time, that in fact BRI2 and BRI3 bind PP1. The complexes BRI2:PP1 and BRI3:PP1 were validated in vitro and in vivo. The subcellular distribution of BRI2 and BRI3 is similar; both localize to the perinuclear area and Golgi apparatus in non-neuronal cells. However, in SH-SY5Y cells, BRI2 and BRI3 could also be detected in elongated cellular projections ('processes') and in rat cortical neurons both are broadly distributed throughout the cell body, neuritis and the nucleus. Consistently, co-localization of BRI2 and BRI3 with PP1 was evident. The functional significance of these complexes is apparent given that both BRI proteins are substrates of PP1, thus simultaneously this is the first report of BRI2 and BRI3 as phosphoproteins. Moreover, we show that when BRI2 is phosphorylated a significant increase in neuronal outgrowth and differentiation is evident. Interestingly, the Alzheimer's amyloid precursor protein (APP), forms a trimeric complex composed of PP1 and Fe65, with PP1 having the capacity to dephosphorylate APP at Thr668 residue. The emerging consensus appears to be that PP1 containing complexes are crucial in regulating signaling events underlying neuropathological conditions.
Collapse
Affiliation(s)
- Filipa Martins
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Sandra Rebelo
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal.
| | - Mariana Santos
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Cândida Zita Cotrim
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Edgar F da Cruz e Silva
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - Odete A B da Cruz e Silva
- Laboratório de Neurociências e Sinalização Celular, Centro de Biologia Celular, iBiMED, SACS, Universidade de Aveiro, Aveiro, Portugal
| |
Collapse
|
41
|
Abstract
Here we review the similarities between a rare inherited disorder, familial British dementia (FBD), and the most common of all late-life neurological conditions, Alzheimer's diseases (AD). We describe the symptoms, pathology and genetics of FBD, the biology of the BRI2 protein and mouse models of FBD and familial Danish dementia. In particular, we focus on the evolving recognition of the importance of protein oligomers and aberrant processing of the amyloid β-protein precursor (APP) - themes that are common to both FBD and AD. The initial discovery that FBD is phenotypically similar to AD, but associated with the deposition of an amyloid peptide (ABri) distinct from the amyloid β-protein (Aβ) led many to assume that amyloid production alone is sufficient to initiate disease and that ABri is the molecular equivalent of Aβ. Parallel with work on Aβ, studies of ABri producing animal models and in vitro ABri toxicity experiments caused a revision of the amyloid hypothesis and a focus on soluble oligomers of Aβ and ABri. Contemporaneous other studies suggested that loss of the ABri precursor protein (BRI2) may underlie the cognitive deficits in FBD. In this regard it is important to note that BRI2 has been shown to interact with and regulate the processing of APP, and that mutant BRI2 leads to altered cleavage of APP. A synthesis of these results suggests that a “two-hit mechanism” better explains FBD than earlier toxic gain of function and toxic loss of function models. The lessons learned from the study of FBD imply that the molecular pathology of AD is also likely to involve both aberrant aggregation (in AD, Aβ) and altered APP processing. With regard to FBD, we propose that the C-terminal 11 amino acid of FBD-BRI2 interfere with both the normal function of BRI2 and promotes the production of cystine cross-linked toxic ABri oligomers. In this scenario, loss of BRI2 function leads to altered APP processing in as yet underappreciated ways. Given the similarities between FBD and AD it seems likely that study of the structure of ABri oligomers and FBD-induced changes in APP metabolites will further our understanding of AD.
Collapse
Affiliation(s)
- Adam Cantlon
- Laboratory for Neurodegenerative Research, School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Republic of Ireland ; Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, USA
| | - Carlo Sala Frigerio
- Laboratory for Neurodegenerative Research, School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Republic of Ireland
| | - Dominic M Walsh
- Laboratory for Neurodegenerative Research, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, USA
| |
Collapse
|
42
|
Landreh M, Rising A, Presto J, Jörnvall H, Johansson J. Specific chaperones and regulatory domains in control of amyloid formation. J Biol Chem 2015; 290:26430-6. [PMID: 26354437 DOI: 10.1074/jbc.r115.653097] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Many proteins can form amyloid-like fibrils in vitro, but only about 30 amyloids are linked to disease, whereas some proteins form physiological amyloid-like assemblies. This raises questions of how the formation of toxic protein species during amyloidogenesis is prevented or contained in vivo. Intrinsic chaperoning or regulatory factors can control the aggregation in different protein systems, thereby preventing unwanted aggregation and enabling the biological use of amyloidogenic proteins. The molecular actions of these chaperones and regulators provide clues to the prevention of amyloid disease, as well as to the harnessing of amyloidogenic proteins in medicine and biotechnology.
Collapse
Affiliation(s)
- Michael Landreh
- From the Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 5QY, United Kingdom
| | - Anna Rising
- the Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Karolinska Institutet - Novum, 141 57 Huddinge, Sweden, the Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, The Biomedical Centre, Box 575, 751 23 Uppsala, Sweden
| | - Jenny Presto
- the Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Karolinska Institutet - Novum, 141 57 Huddinge, Sweden
| | - Hans Jörnvall
- the Department of Medical Biochemistry and Biophysics (MBB), Karolinska Institutet, SE-171 77 Stockholm, Sweden, and
| | - Jan Johansson
- the Department of Neurobiology, Care Sciences and Society (NVS), Center for Alzheimer Research, Karolinska Institutet - Novum, 141 57 Huddinge, Sweden, the Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, The Biomedical Centre, Box 575, 751 23 Uppsala, Sweden, the Institute of Mathematics and Natural Sciences, Tallinn University, Narva mnt 25, 101 20 Tallinn, Estonia
| |
Collapse
|
43
|
Del Campo M, Oliveira CR, Scheper W, Zwart R, Korth C, Müller-Schiffmann A, Kostallas G, Biverstal H, Presto J, Johansson J, Hoozemans JJ, Pereira CF, Teunissen CE. BRI2 ectodomain affects Aβ42 fibrillation and tau truncation in human neuroblastoma cells. Cell Mol Life Sci 2015; 72:1599-611. [PMID: 25336154 PMCID: PMC11113771 DOI: 10.1007/s00018-014-1769-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 10/15/2014] [Accepted: 10/17/2014] [Indexed: 11/29/2022]
Abstract
Alzheimer's disease (AD) is pathologically characterized by the presence of misfolded proteins such as amyloid beta (Aβ) in senile plaques, and hyperphosphorylated tau and truncated tau in neurofibrillary tangles (NFT). The BRI2 protein inhibits Aβ aggregation via its BRICHOS domain and regulates critical proteins involved in initiating the amyloid cascade, which has been hypothesized to be central in AD pathogenesis. We recently detected the deposition of BRI2 ectodomain associated with Aβ plaques and concomitant changes in its processing enzymes in early stages of AD. Here, we aimed to investigate the effects of recombinant BRI2 ectodomain (rBRI276-266) on Aβ aggregation and on important molecular pathways involved in early stages of AD, including the unfolded protein response (UPR), phosphorylation and truncation of tau, as well as apoptosis. We found that rBRI276-266 delays Aβ fibril formation, although less efficiently than the BRI2 BRICHOS domain (BRI2 residues 113-231). In human neuroblastoma SH-SY5Y cells, rBRI276-266 slightly decreased cell viability and increased up to two-fold the Bax/Bcl-2 ratio and the subsequent activity of caspases 3 and 9, indicating activation of apoptosis. rBRI276-266 upregulated the chaperone BiP but did not modify the mRNA expression of other UPR markers (CHOP and Xbp-1). Strikingly, rBRI276-266 induced the activation of GSK3β but not the phosphorylation of tau. However, exposure to rBRI276-266 significantly induced the truncation of tau, indicating that BRI2 ectodomain can contribute to NFT formation. Since BRI2 can also regulate the metabolism of Aβ, the current data suggests that BRI2 ectodomain is a potential nexus between Aβ, tau pathology and neurodegeneration.
Collapse
Affiliation(s)
- M Del Campo
- Neurochemistry Laboratory, Department of Clinical Chemistry, VU University Medical Center (VUmc), Room PK1 Br016, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands,
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Del Campo M, Stargardt A, Veerhuis R, Reits E, Teunissen CE. Accumulation of BRI2-BRICHOS ectodomain correlates with a decreased clearance of Aβ by insulin degrading enzyme (IDE) in Alzheimer's disease. Neurosci Lett 2015; 589:47-51. [PMID: 25597881 DOI: 10.1016/j.neulet.2015.01.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 01/22/2023]
Abstract
The precursor protein BRI2 that in its mutated form is associated with British and Danish dementia, can regulate critical processes involved in AD pathogenesis including not only the metabolism of amyloid precursor protein (APP) and formation of Aβ, but also the levels of secreted insulin degrading enzyme (IDE), an enzyme involved in Aβ clearance. We recently observed increased levels of a 45kDa BRI2 form as well as BRI2 ectodomain deposits in Aβ plaques in human AD hippocampus, which may affect BRI2 functional activity. Since BRI2 regulated the levels of secreted IDE and subsequent degradation of Aβ in human cell culture models, we explored if BRI2 changes could affect the Aβ degradation capacity of IDE in human hippocampus (n=28). We observed that IDE is the main enzyme involved in Aβ degradation, and both IDE levels as well as Aβ degradation tend to be decreased in AD. Interestingly, the levels of the 45kDa BRI2 form and BRI2 deposits in hippocampal tissue were inversely correlated with IDE protein levels (r=-0.52, p=0.005; r=-0.4, p=0.045) and IDE activity (r=-0.5935, p=0.0004; r=-0.4, p=0.03). Taken together, the current results suggest a relationship between BRI2 protein changes, IDE activity and Aβ levels in human hippocampus. Thus, the formation and accumulation high of molecular weight BRI2 forms observed in AD may impair IDE functioning and consequently lead to impaired Aβ clearance and to the accumulation of Aβ.
Collapse
Affiliation(s)
- M Del Campo
- Neurochemistry Laboratory of the Clinical Chemistry department, VU University Medical Center, 1081HV, Amsterdam, The Netherlands; Alzheimer Center, VU University Medical Center, 1081HV, Amsterdam, The Netherlands.
| | - A Stargardt
- Department of Cell Biology and Histology, Academic Medical Center, Amsterdam, The Netherlands
| | - R Veerhuis
- Neurochemistry Laboratory of the Clinical Chemistry department, VU University Medical Center, 1081HV, Amsterdam, The Netherlands; Psychiatry department, VU University Medical Center, 1081HV, Amsterdam, The Netherlands
| | - E Reits
- Department of Cell Biology and Histology, Academic Medical Center, Amsterdam, The Netherlands
| | - C E Teunissen
- Neurochemistry Laboratory of the Clinical Chemistry department, VU University Medical Center, 1081HV, Amsterdam, The Netherlands
| |
Collapse
|
45
|
The ITM2B (BRI2) gene is a target of BCL6 repression: Implications for lymphomas and neurodegenerative diseases. Biochim Biophys Acta Mol Basis Dis 2014; 1852:742-8. [PMID: 25557390 DOI: 10.1016/j.bbadis.2014.12.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Revised: 12/21/2014] [Accepted: 12/25/2014] [Indexed: 11/20/2022]
Abstract
The human BCL6 gene encodes a transcriptional repressor that is crucial for germinal center B cell development and T follicular helper cell differentiation. It is involved in the pathogenesis of certain human lymphomas. In an effort to identify targets of BCL6 repression, we used a previously described cell system in which BCL6 repressive effects are inhibited, followed by subtractive hybridization, and identified the integral membrane 2B gene (ITM2B, formerly BRI2) as a potential target. Here we show that BCL6 can bind to its preferential consensus binding site within the first intron of ITM2B and represses its transcription. Knockdown of endogenous BCL6 in a human B cell lymphoma line increases ITM2B expression. Further, there is an inverse relationship between the expression levels of BCL6 and ITM2B proteins in 16 human B- and T-cell lymphomas studied by immunohistochemistry. Both the BCL6 and ITM2B proteins are expressed ubiquitously. Similar to some other targets of BCL6, a short form of the ITM2B protein generated by alternative splicing induces apoptosis in hematopoietic cell lines. Molecular alterations in the ITM2B gene are associated with two neurodegenerative diseases, Familial British and Familial Danish dementia. ITM2B dysfunction also may be relevant for the development of Alzheimer's disease. Our data confirm ITM2B as a target of BCL6 repression in lymphoma. A further understanding of the genes that function as regulators of the ITM2B protein may provide insights for the development of new molecular tools not only for targeted lymphoma therapy but also for the treatment of these dementias.
Collapse
|
46
|
Del Prete D, Lombino F, Liu X, D'Adamio L. APP is cleaved by Bace1 in pre-synaptic vesicles and establishes a pre-synaptic interactome, via its intracellular domain, with molecular complexes that regulate pre-synaptic vesicles functions. PLoS One 2014; 9:e108576. [PMID: 25247712 PMCID: PMC4172690 DOI: 10.1371/journal.pone.0108576] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 08/31/2014] [Indexed: 12/21/2022] Open
Abstract
Amyloid Precursor Protein (APP) is a type I membrane protein that undergoes extensive processing by secretases, including BACE1. Although mutations in APP and genes that regulate processing of APP, such as PSENs and BRI2/ITM2B, cause dementias, the normal function of APP in synaptic transmission, synaptic plasticity and memory formation is poorly understood. To grasp the biochemical mechanisms underlying the function of APP in the central nervous system, it is important to first define the sub-cellular localization of APP in synapses and the synaptic interactome of APP. Using biochemical and electron microscopy approaches, we have found that APP is localized in pre-synaptic vesicles, where it is processed by Bace1. By means of a proteomic approach, we have characterized the synaptic interactome of the APP intracellular domain. We focused on this region of APP because in vivo data underline the central functional and pathological role of the intracellular domain of APP. Consistent with the expression of APP in pre-synaptic vesicles, the synaptic APP intracellular domain interactome is predominantly constituted by pre-synaptic, rather than post-synaptic, proteins. This pre-synaptic interactome of the APP intracellular domain includes proteins expressed on pre-synaptic vesicles such as the vesicular SNARE Vamp2/Vamp1 and the Ca2+ sensors Synaptotagmin-1/Synaptotagmin-2, and non-vesicular pre-synaptic proteins that regulate exocytosis, endocytosis and recycling of pre-synaptic vesicles, such as target-membrane-SNAREs (Syntaxin-1b, Syntaxin-1a, Snap25 and Snap47), Munc-18, Nsf, α/β/γ-Snaps and complexin. These data are consistent with a functional role for APP, via its carboxyl-terminal domain, in exocytosis, endocytosis and/or recycling of pre-synaptic vesicles.
Collapse
Affiliation(s)
- Dolores Del Prete
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Franco Lombino
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Xinran Liu
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Luciano D'Adamio
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| |
Collapse
|
47
|
Del Campo M, Hoozemans JJM, Dekkers LL, Rozemuller AJ, Korth C, Müller-Schiffmann A, Scheltens P, Blankenstein MA, Jimenez CR, Veerhuis R, Teunissen CE. BRI2-BRICHOS is increased in human amyloid plaques in early stages of Alzheimer's disease. Neurobiol Aging 2014; 35:1596-604. [PMID: 24524963 DOI: 10.1016/j.neurobiolaging.2014.01.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 12/31/2013] [Accepted: 01/08/2014] [Indexed: 10/25/2022]
Abstract
BRI2 protein binds amyloid precursor protein to halt amyloid-β production and inhibits amyloid-β aggregation via its BRICHOS-domain suggesting a link between BRI2 and Alzheimer's disease (AD). Here, we investigate the possible involvement of BRI2 in human AD pathogenesis. BRI2 containing BRICHOS-domain was increased up to 3-fold in AD hippocampus (p = 0.003, n = 14/group). Immunohistochemistry showed BRI2 deposits associated with amyloid-β plaques in early pathologic stages (Braak-III; Thal-2/3). We observed a decrease in the protein levels of ADAM10 (p = 0.02) and furin (p = 0.066), as well as an increase in SPPL2b (p < 0.0001) in AD hippocampus. Because these enzymes are involved in BRI2 processing, their changes may lead to aberrant processing of BRI2 promoting its deposition and likely affecting BRI2 function. Loss of BRI2 function in AD was supported by the decreased presence of BRI2-amyloid precursor protein complexes in the hippocampus of AD patients compared with control subjects. In conclusion, our data obtained from human samples indicate that in early stages of AD there is an increased deposition of BRI2, which likely leads to impaired BRI2 function thereby influencing AD pathophysiology.
Collapse
Affiliation(s)
- Marta Del Campo
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, the Netherlands; Neurochemistry Laboratory, VU University Medical Center, Amsterdam, the Netherlands; Alzheimer Center, VU University Medical Center, Amsterdam, the Netherlands.
| | - Jeroen J M Hoozemans
- Department of Pathology, VU University Medical Center, Amsterdam, the Netherlands
| | - Lois-Lee Dekkers
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, the Netherlands; Neurochemistry Laboratory, VU University Medical Center, Amsterdam, the Netherlands
| | | | - Carsten Korth
- Department of Neuropathology, Heinrich Heine University Medical School, Düsseldorf, Germany
| | | | - Philip Scheltens
- Alzheimer Center, VU University Medical Center, Amsterdam, the Netherlands
| | - Marinus A Blankenstein
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, the Netherlands; Neurochemistry Laboratory, VU University Medical Center, Amsterdam, the Netherlands
| | - Connie R Jimenez
- Department of Medical Oncology and OncoProteomics Laboratory, VU University Medical Center, Amsterdam, the Netherlands
| | - Robert Veerhuis
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, the Netherlands; Neurochemistry Laboratory, VU University Medical Center, Amsterdam, the Netherlands; Department of Pathology, VU University Medical Center, Amsterdam, the Netherlands; Department of Psychiatry, VU University Medical Center, Amsterdam, the Netherlands
| | - Charlotte E Teunissen
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, the Netherlands; Neurochemistry Laboratory, VU University Medical Center, Amsterdam, the Netherlands
| |
Collapse
|
48
|
Audo I, Bujakowska K, Orhan E, El Shamieh S, Sennlaub F, Guillonneau X, Antonio A, Michiels C, Lancelot ME, Letexier M, Saraiva JP, Nguyen H, Luu TD, Léveillard T, Poch O, Dollfus H, Paques M, Goureau O, Mohand-Saïd S, Bhattacharya SS, Sahel JA, Zeitz C. The familial dementia gene revisited: a missense mutation revealed by whole-exome sequencing identifies ITM2B as a candidate gene underlying a novel autosomal dominant retinal dystrophy in a large family. Hum Mol Genet 2013; 23:491-501. [PMID: 24026677 DOI: 10.1093/hmg/ddt439] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Inherited retinal diseases are a group of clinically and genetically heterogeneous disorders for which a significant number of cases remain genetically unresolved. Increasing knowledge on underlying pathogenic mechanisms with precise phenotype-genotype correlation is, however, critical for establishing novel therapeutic interventions for these yet incurable neurodegenerative conditions. We report phenotypic and genetic characterization of a large family presenting an unusual autosomal dominant retinal dystrophy. Phenotypic characterization revealed a retinopathy dominated by inner retinal dysfunction and ganglion cell abnormalities. Whole-exome sequencing identified a missense variant (c.782A>C, p.Glu261Ala) in ITM2B coding for Integral Membrane Protein 2B, which co-segregates with the disease in this large family and lies within the 24.6 Mb interval identified by microsatellite haplotyping. The physiological role of ITM2B remains unclear and has never been investigated in the retina. RNA in situ hybridization reveals Itm2b mRNA in inner nuclear and ganglion cell layers within the retina, with immunostaining demonstrating the presence of the corresponding protein in the same layers. Furthermore, ITM2B in the retina co-localizes with its known interacting partner in cerebral tissue, the amyloid β precursor protein, critical in Alzheimer disease physiopathology. Interestingly, two distinct ITM2B mutations, both resulting in a longer protein product, had already been reported in two large autosomal dominant families with Alzheimer-like dementia but never in subjects with isolated retinal diseases. These findings should better define pathogenic mechanism(s) associated with ITM2B mutations underlying dementia or retinal disease and add a new candidate to the list of genes involved in inherited retinal dystrophies.
Collapse
|
49
|
Lombino F, Biundo F, Tamayev R, Arancio O, D’Adamio L. An intracellular threonine of amyloid-β precursor protein mediates synaptic plasticity deficits and memory loss. PLoS One 2013; 8:e57120. [PMID: 23451158 PMCID: PMC3579798 DOI: 10.1371/journal.pone.0057120] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 01/17/2013] [Indexed: 11/22/2022] Open
Abstract
Mutations in Amyloid-ß Precursor Protein (APP) and BRI2/ITM2b genes cause Familial Alzheimer and Danish Dementias (FAD/FDD), respectively. APP processing by BACE1, which is inhibited by BRI2, yields sAPPß and ß-CTF. ß-CTF is cleaved by gamma-secretase to produce Aß. A knock-in mouse model of FDD, called FDDKI, shows deficits in memory and synaptic plasticity, which can be attributed to sAPPß/ß-CTF but not Aß. We have investigated further the pathogenic function of ß-CTF focusing on Thr(668) of ß-CTF because phosphorylation of Thr(668) is increased in AD cases. We created a knock-in mouse bearing a Thr(668)Ala mutation (APP(TA) mice) that prevents phosphorylation at this site. This mutation prevents the development of memory and synaptic plasticity deficits in FDDKI mice. These data are consistent with a role for the carboxyl-terminal APP domain in the pathogenesis of dementia and suggest that averting the noxious role of Thr(668) is a viable therapeutic strategy for human dementias.
Collapse
Affiliation(s)
- Franco Lombino
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Fabrizio Biundo
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Robert Tamayev
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Ottavio Arancio
- Department of Pathology & Cell Biology, Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, New York, United States of America
| | - Luciano D’Adamio
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| |
Collapse
|
50
|
Tamayev R, Akpan N, Arancio O, Troy CM, D'Adamio L. Caspase-9 mediates synaptic plasticity and memory deficits of Danish dementia knock-in mice: caspase-9 inhibition provides therapeutic protection. Mol Neurodegener 2012; 7:60. [PMID: 23217200 PMCID: PMC3543220 DOI: 10.1186/1750-1326-7-60] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 12/05/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mutations in either Aβ Precursor protein (APP) or genes that regulate APP processing, such as BRI2/ITM2B and PSEN1/PSEN2, cause familial dementias. Although dementias due to APP/PSEN1/PSEN2 mutations are classified as familial Alzheimer disease (FAD) and those due to mutations in BRI2/ITM2B as British and Danish dementias (FBD, FDD), data suggest that these diseases have a common pathogenesis involving toxic APP metabolites. It was previously shown that FAD mutations in APP and PSENs promote activation of caspases leading to the hypothesis that aberrant caspase activation could participate in AD pathogenesis. RESULTS Here, we tested whether a similar mechanism applies to the Danish BRI2/ITM2B mutation. We have generated a genetically congruous mouse model of FDD, called FDD(KI), which presents memory and synaptic plasticity deficits. We found that caspase-9 is activated in hippocampal synaptic fractions of FDD(KI) mice and inhibition of caspase-9 activity rescues both synaptic plasticity and memory deficits. CONCLUSION These data directly implicate caspase-9 in the pathogenesis of Danish dementia and suggest that reducing caspase-9 activity is a valid therapeutic approach to treating human dementias.
Collapse
Affiliation(s)
- Robert Tamayev
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | | | | | | | |
Collapse
|