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Silvaieh S, König T, Wurm R, Parvizi T, Berger-Sieczkowski E, Goeschl S, Hotzy C, Wagner M, Berutti R, Sammler E, Stögmann E, Zimprich A. Comprehensive genetic screening of early-onset dementia patients in an Austrian cohort-suggesting new disease-contributing genes. Hum Genomics 2023; 17:55. [PMID: 37330543 PMCID: PMC10276391 DOI: 10.1186/s40246-023-00499-z] [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: 03/06/2023] [Accepted: 05/31/2023] [Indexed: 06/19/2023] Open
Abstract
Early-onset dementia (EOD), with symptom onset before age 65, has a strong genetic burden. Due to genetic and clinical overlaps between different types of dementia, whole-exome sequencing (WES) has emerged as an appropriate screening method for diagnostic testing and novel gene-finding approaches. We performed WES and C9orf72 repeat testing in 60 well-defined Austrian EOD patients. Seven patients (12%) carried likely disease-causing variants in monogenic genes, PSEN1, MAPT, APP, and GRN. Five patients (8%) were APOE4 homozygote carriers. Definite and possible risk variants were detected in the genes TREM2, SORL1, ABCA7 and TBK1. In an explorative approach, we cross-checked rare gene variants in our cohort with a curated neurodegeneration candidate gene list and identified DCTN1, MAPK8IP3, LRRK2, VPS13C and BACE1 as promising candidate genes. Conclusively, 12 cases (20%) carried variants relevant to patient counseling, comparable to previously reported studies, and can thus be considered genetically resolved. Reduced penetrance, oligogenic inheritance and not yet identified high-risk genes might explain the high number of unresolved cases. To address this issue, we provide complete genetic and phenotypic information (uploaded to the European Genome-phenome Archive), enabling other researchers to cross-check variants. Thereby, we hope to increase the chance of independently finding the same gene/variant-hit in other well-defined EOD patient cohorts, thus confirming new genetic risk variants or variant combinations.
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Affiliation(s)
- Sara Silvaieh
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Theresa König
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Raphael Wurm
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Tandis Parvizi
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Evelyn Berger-Sieczkowski
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Stella Goeschl
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Christoph Hotzy
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Matias Wagner
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
- Institute of Neurogenomics, Helmholtz Centrum, Munich, Germany
| | - Riccardo Berutti
- Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Esther Sammler
- Molecular and Clinical Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, UK
- Medical Research Council Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Elisabeth Stögmann
- Department of Neurology, Medical University of Vienna, Vienna, Austria.
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria.
| | - Alexander Zimprich
- Department of Neurology, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
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2
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Keable R, Hu S, Pfundstein G, Kozlova I, Su F, Du X, Yang H, Gunnersen J, Schachner M, Leshchyns'ka I, Sytnyk V. The BACE1-generated C-terminal fragment of the neural cell adhesion molecule 2 (NCAM2) promotes BACE1 targeting to Rab11-positive endosomes. Cell Mol Life Sci 2022; 79:555. [PMID: 36251052 PMCID: PMC9576659 DOI: 10.1007/s00018-022-04575-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 09/16/2022] [Accepted: 09/27/2022] [Indexed: 11/08/2022]
Abstract
Beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), also known as β-secretase, is an aspartic protease. The sorting of this enzyme into Rab11-positive recycling endosomes regulates the BACE1-mediated cleavage of its substrates, however, the mechanisms underlying this targeting remain poorly understood. The neural cell adhesion molecule 2 (NCAM2) is a substrate of BACE1. We show that BACE1 cleaves NCAM2 in cultured hippocampal neurons and NCAM2-transfected CHO cells. The C-terminal fragment of NCAM2 that comprises the intracellular domain and a small portion of NCAM2’s extracellular domain, associates with BACE1. This association is not affected in cells with inhibited endocytosis, indicating that the interaction of NCAM2 and BACE1 precedes the targeting of BACE1 from the cell surface to endosomes. In neurons and CHO cells, this fragment and BACE1 co-localize in Rab11-positive endosomes. Overexpression of full-length NCAM2 or a recombinant NCAM2 fragment containing the transmembrane and intracellular domains but lacking the extracellular domain leads to an increase in BACE1 levels in these organelles. In NCAM2-deficient neurons, the levels of BACE1 are increased at the cell surface and reduced in intracellular organelles. These effects are correlated with increased levels of the soluble extracellular domain of BACE1 in the brains of NCAM2-deficient mice, suggesting increased shedding of BACE1 from the cell surface. Of note, shedding of the extracellular domain of Sez6, a protein cleaved exclusively by BACE1, is reduced in NCAM2-deficient animals. These results indicate that the BACE1-generated fragment of NCAM2 regulates BACE1 activity by promoting the targeting of BACE1 to Rab11-positive endosomes.
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Affiliation(s)
- Ryan Keable
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Shangfeng Hu
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Grant Pfundstein
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Irina Kozlova
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Feifei Su
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Ximing Du
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Jenny Gunnersen
- Department of Anatomy and Physiology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Melitta Schachner
- Department of Cell Biology and Neuroscience, Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway, NJ, 08554, USA
| | - Iryna Leshchyns'ka
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Vladimir Sytnyk
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia.
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3
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Shen Q, Wu X, Zhang Z, Zhang D, Yang S, Xing D. Gamma frequency light flicker regulates amyloid precursor protein trafficking for reducing β-amyloid load in Alzheimer's disease model. Aging Cell 2022; 21:e13573. [PMID: 35199454 PMCID: PMC8920449 DOI: 10.1111/acel.13573] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 01/05/2022] [Accepted: 02/02/2022] [Indexed: 11/28/2022] Open
Abstract
Inducing gamma oscillations with non‐invasive light flicker has been reported to impact Alzheimer's disease‐related pathology. However, it is unclear which signaling pathways are involved in reducing amyloid load. Here, we found that gamma frequency light flicker increased anchoring of amyloid precursor protein (APP) to the plasma membrane for non‐amyloidogenic processing, and then physically interacted with KCC2, a neuron‐specific K+‐Cl− cotransporter, suggesting that it is essential to maintain surface GABAA receptor α1 levels and reduce β‐amyloid (Aβ) production. Stimulation with such light flicker limited KCC2 internalization and subsequent degradation via both tyrosine phosphorylation and ubiquitination, leading to an increase in surface‐KCC2 levels. Specifically, PKC‐dependent phosphorylation of APP on a serine residue was induced by gamma frequency light flicker, which was responsible for maintaining plasma membrane levels of full‐length APP, leading to its reduced trafficking to endosomes and inhibiting the β‐secretase cleavage pathway. The activated PKC from the gamma frequency light flicker subsequently phosphorylated serine of KCC2 and stabilized it onto the cell surface, which contributed to the upregulation of surface GABAA receptor α1 levels. Together, these data indicate that enhancement of APP trafficking to the plasma membrane via light flicker plays a critical modulatory role in reduction of Aβ load in Alzheimer's disease.
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Affiliation(s)
- Qi Shen
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou China
- College of Biophotonics South China Normal University Guangzhou China
| | - Xiaolei Wu
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou China
- College of Biophotonics South China Normal University Guangzhou China
| | - Zhan Zhang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou China
- College of Biophotonics South China Normal University Guangzhou China
| | - Di Zhang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou China
- College of Biophotonics South China Normal University Guangzhou China
| | - Sihua Yang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou China
- College of Biophotonics South China Normal University Guangzhou China
| | - Da Xing
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou China
- College of Biophotonics South China Normal University Guangzhou China
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Urban AS, Bershatskii YV, Pavlov KV, Bocharov EV. Structural Study of Membrane Glycoprotein-Precursor of β-Amyloid and Proteins Involved in Its Proteolysis. CRYSTALLOGR REP+ 2021. [DOI: 10.1134/s1063774521050229] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Du H, Wong MY, Zhang T, Santos MN, Hsu C, Zhang J, Yu H, Luo W, Hu F. A multifaceted role of progranulin in regulating amyloid-beta dynamics and responses. Life Sci Alliance 2021; 4:e202000874. [PMID: 34103390 PMCID: PMC8200295 DOI: 10.26508/lsa.202000874] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 05/26/2021] [Accepted: 05/26/2021] [Indexed: 01/07/2023] Open
Abstract
Haploinsufficiency of progranulin (PGRN) is a leading cause of frontotemporal lobar degeneration (FTLD). PGRN polymorphisms are associated with Alzheimer's disease. PGRN is highly expressed in the microglia near Aβ plaques and influences plaque dynamics and microglial activation. However, the detailed mechanisms remain elusive. Here we report that PGRN deficiency reduces human APP and Aβ levels in the young male but not female mice. PGRN-deficient microglia exhibit increased expression of markers associated with microglial activation, including CD68, galectin-3, TREM2, and GPNMB, specifically near Aβ plaques. In addition, PGRN loss leads to up-regulation of lysosome proteins and an increase in the nuclear localization of TFE3, a transcription factor involved in lysosome biogenesis. Cultured PGRN-deficient microglia show enhanced nuclear translocation of TFE3 and inflammation in response to Aβ fibril treatment. Taken together, our data revealed a sex- and age-dependent effect of PGRN on APP metabolism and a role of PGRN in regulating lysosomal activities and inflammation in plaque-associated microglia.
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Affiliation(s)
- Huan Du
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Man Ying Wong
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Tingting Zhang
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Mariela Nunez Santos
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Charlene Hsu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Junke Zhang
- Department of Computational Biology, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Haiyuan Yu
- Department of Computational Biology, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, USA
| | - Wenjie Luo
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Fenghua Hu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
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Farris F, Matafora V, Bachi A. The emerging role of β-secretases in cancer. J Exp Clin Cancer Res 2021; 40:147. [PMID: 33926496 PMCID: PMC8082908 DOI: 10.1186/s13046-021-01953-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 04/19/2021] [Indexed: 01/08/2023] Open
Abstract
BACE1 and BACE2 belong to a class of proteases called β-secretases involved in ectodomain shedding of different transmembrane substrates. These enzymes have been extensively studied in Alzheimer's disease as they are responsible for the processing of APP in neurotoxic Aβ peptides. These proteases, especially BACE2, are overexpressed in tumors and correlate with poor prognosis. Recently, different research groups tried to address the role of BACE1 and 2 in cancer development and progression. In this review, we summarize the latest findings on β-secretases in cancer, highlighting the mechanisms that build the rationale to propose inhibitors of these proteins as a new line of treatment for different tumor types.
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Affiliation(s)
| | | | - Angela Bachi
- IFOM- FIRC Institute of Molecular Oncology, Milan, Italy.
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7
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Live-cell monitoring of protein localization to membrane rafts using protein-fragment complementation. Biosci Rep 2021; 40:221616. [PMID: 31850494 PMCID: PMC6944658 DOI: 10.1042/bsr20191290] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 12/13/2019] [Accepted: 12/17/2019] [Indexed: 12/12/2022] Open
Abstract
The plasma membrane consists of a variety of discrete domains differing from the surrounding membrane in composition and properties. Selective partitioning of protein to these microdomains is essential for membrane functioning and integrity. Studying the nanoscale size and dynamic nature of the membrane microdomains requires advanced imaging approaches with a high spatiotemporal resolution and, consequently, expensive and specialized equipment, unavailable for most researchers and unsuited for large-scale studies. Thus, understanding of protein partitioning to the membrane microdomains in health and disease is still hampered by the lack of inexpensive live-cell approaches with an appropriate spatial resolution. Here, we have developed a novel approach based on Gaussia princeps luciferase protein-fragment complementation assay to quantitively investigate protein partitioning to cholesterol and sphingomyelin-rich domains, sometimes called ‘lipid rafts’, in intact living cells with a high-spatial resolution. In the assay, the reporter construct, carrying one half of the luciferase protein, is targeted to lipid microdomains through the fused acetylation motif from Src-family kinase Fyn. A protein of interest carries the second half of the luciferase protein. Together, this serves as a reversible real-time sensor of raft recruitment for the studied protein. We demonstrated that the assay can efficiently detect the dynamic alterations in raft localization of two disease-associated proteins: Akt and APP. Importantly, this method can be used in high-throughput screenings and other large-scale studies in living cells. This inexpensive, and easy to implement raft localization assay will benefit all researchers interested in protein partitioning in rafts.
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8
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Abbaszadeh M, Sahin M, Ozgun A, Oncu G, Garipcan B, Saybasili H. A Transient Survival Model of Alteration of Electrophysiological Properties Due to Amyloid Beta Toxicity Based on SH-SY5Y Cell Line. Curr Alzheimer Res 2021; 17:1208-1213. [PMID: 33583383 DOI: 10.2174/1567205018666210212155750] [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: 03/29/2020] [Revised: 10/26/2020] [Accepted: 12/21/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Accumulation of toxic strands of amyloid beta (AB), which cause neurofibrillary tangles and, ultimately, cell death, is suspected to be the main culprit behind clinical symptoms of Alzheimer's disease. Although the mechanism of cell death due to AB accumulation is well known, the intermediate phase between the start of accumulation and cell death is less known and investigated, partially due to technical challenges in identifying partially affected cells. OBJECTIVE First, we aimed to establish an in vitro model that would show resilience against AB toxicity. Then we used morphological, molecular and electrophysiological assays to investigate how the characteristics of the surviving cells changed after AB toxicity. METHODS To investigate this phase, we used differentiation of SH-SY5Y neuroblastoma stem cells by Retinoic Acid (RA) and Brain Derived Neurotrophic Factor (BDNF) to establish an in vitro model which would be able to demonstrate various levels of resistance to AB toxicity. We utilized fluorescent microscopy and whole cell patch clamp recordings to investigate behavior of the model. RESULTS We observed significantly higher morphological resilience against AB toxicity in cells which were differentiated by both Retinoic Acid and Brain Derived Neurotrophic Factor compared to Retinoic Acid only. However, the electrophysiological properties of the Retinoic Acid + Brain-Derived Neurotrophic Factor differentiated cells were significantly altered after AB treatment. CONCLUSION We established a transient survival model for AB toxicity and observed the effects of AB on transmembrane currents of differentiated neurons.
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Affiliation(s)
- Morteza Abbaszadeh
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
| | - Meryem Sahin
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
| | - Alp Ozgun
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
| | - Gul Oncu
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
| | - Bora Garipcan
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
| | - Hale Saybasili
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
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Hrabinova M, Pejchal J, Kucera T, Jun D, Schmidt M, Soukup O. Is It the Twilight of BACE1 Inhibitors? Curr Neuropharmacol 2021; 19:61-77. [PMID: 32359337 PMCID: PMC7903497 DOI: 10.2174/1570159x18666200503023323] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/23/2020] [Accepted: 04/30/2020] [Indexed: 12/13/2022] Open
Abstract
β-secretase (BACE1) has been regarded as a prime target for the development of amyloid beta (Aβ) lowering drugs in the therapy of Alzheimer´s disease (AD). Although the enzyme was discovered in 1991 and helped to formulate the Aβ hypothesis as one of the very important features of AD etiopathogenesis, progress in AD treatment utilizing BACE1 inhibitors has remained limited. Moreover, in the last years, major pharmaceutical companies have discontinued clinical trials of five BACE1 inhibitors that had been strongly perceived as prospective. In our review, the Aβ hypothesis, the enzyme, its functions, and selected substrates are described. BACE1 inhibitors are classified into four generations. Those that underwent clinical trials displayed adverse effects, including weight loss, skin rashes, worsening of neuropsychiatric symptoms, etc. Some inhibitors could not establish a statistically significant risk-benefit ratio, or even scored worse than placebo. We still believe that drugs targeting BACE1 may still hide some potential, but a different approach to BACE1 inhibition or a shift of focus to modulation of its trafficking and/or post-translational modification should now be followed.
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Affiliation(s)
| | - Jaroslav Pejchal
- Address correspondence to this author at the Department of Toxicology and Military Pharmacy, Faculty of Military Health Sciences, University of Defence in Brno, Hradec Kralove, Czech Republic;E-mail:
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10
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Hampel H, Lista S, Vanmechelen E, Zetterberg H, Giorgi FS, Galgani A, Blennow K, Caraci F, Das B, Yan R, Vergallo A. β-Secretase1 biological markers for Alzheimer's disease: state-of-art of validation and qualification. Alzheimers Res Ther 2020; 12:130. [PMID: 33066807 PMCID: PMC7566058 DOI: 10.1186/s13195-020-00686-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/15/2020] [Indexed: 01/09/2023]
Abstract
β-Secretase1 (BACE1) protein concentrations and rates of enzyme activity, analyzed in human bodily fluids, are promising candidate biological markers for guidance in clinical trials investigating BACE1 inhibitors to halt or delay the dysregulation of the amyloid-β pathway in Alzheimer's disease (AD). A robust body of evidence demonstrates an association between cerebrospinal fluid/blood BACE1 biomarkers and core pathophysiological mechanisms of AD, such as brain protein misfolding and aggregration, neurodegeneration, and synaptic dysfunction.In pharmacological trials, BACE1 candidate biomarkers may be applied to a wide set of contexts of use (CoU), including proof of mechanism, dose-finding, response and toxicity dose estimation. For clinical CoU, BACE1 biomarkers show good performance for prognosis and disease prediction.The roadmap toward validation and qualification of BACE1 biomarkers requires standardized pre-analytical and analytical protocols to reduce inter-site variance that may have contributed to inconsistent results.BACE1 biomarker-drug co-development programs, including biomarker-guided outcomes and endpoints, may support the identification of sub-populations with a higher probability to benefit from BACE1 inhibitors with a reduced risk of adverse effects, in line with the evolving precision medicine paradigm.
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Affiliation(s)
- Harald Hampel
- Sorbonne University, GRC no 21, Alzheimer Precision Medicine (APM), AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Simone Lista
- Sorbonne University, GRC no 21, Alzheimer Precision Medicine (APM), AP-HP, Pitié-Salpêtrière Hospital, Paris, France
- Brain & Spine Institute (ICM), INSERM U 1127, CNRS UMR 7225, Boulevard de l'hôpital, F-75013, Paris, France
- Institute of Memory and Alzheimer's Disease (IM2A), Department of Neurology, Pitié-Salpêtrière Hospital, AP-HP, Boulevard de l'hôpital, F-75013, Paris, France
| | | | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
- UK Dementia Research Institute at UCL, London, UK
| | - Filippo Sean Giorgi
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Alessandro Galgani
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Kaj Blennow
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
| | - Filippo Caraci
- Department of Drug Sciences, University of Catania, Catania, Italy
- Oasi Research Institute-IRCCS, Troina, Italy
| | - Brati Das
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, USA
| | - Riqiang Yan
- Department of Neuroscience, University of Connecticut Health, Farmington, CT, USA
| | - Andrea Vergallo
- Sorbonne University, GRC no 21, Alzheimer Precision Medicine (APM), AP-HP, Pitié-Salpêtrière Hospital, Paris, France.
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11
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Ovsepian SV, Horacek J, O'Leary VB, Hoschl C. The Ups and Downs of BACE1: Walking a Fine Line between Neurocognitive and Other Psychiatric Symptoms of Alzheimer's Disease. Neuroscientist 2020; 27:222-234. [PMID: 32713260 DOI: 10.1177/1073858420940943] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although neurocognitive deficit is the best-recognized indicator of Alzheimer's disease (AD), psychotic and other noncognitive symptoms are the prime cause of institutionalization. BACE1 is the rate-limiting enzyme in the production of Aβ of AD, and one of the promising therapeutic targets in countering cognitive decline and amyloid pathology. Changes in BACE1 activity have also emerged to cause significant noncognitive neuropsychiatric symptoms and impairments of circadian rhythms, as evident from clinical trials and reports in transgenic models. In this study, we consider key characteristics of BACE1 with its contribution to neurocognitive deficit and other psychiatric symptoms of AD. We argue that a growing list of noncognitive mental impairments related to pharmacological modulation of BACE1 might present a major obstacle in clinical translation of emerging therapeutic leads targeting this protease. The adverse effects of BACE1 inhibition on mental health call for a revision of treatment strategies that assume indiscriminate inhibition of this key protease, and stress the need for further mechanistic and translational studies.
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Affiliation(s)
- Saak V Ovsepian
- National Institute of Mental Health, Klecany, Czech Republic.,Department of Psychiatry and Medical Psychology, Third Faculty of Medicine, Charles University, Prague, Czech Republic.,International Centre for Neurotherapeutics, Dublin City University, Dublin, Ireland
| | - Jiri Horacek
- National Institute of Mental Health, Klecany, Czech Republic
| | - Valerie B O'Leary
- Department of Medical Genetics, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Cyril Hoschl
- National Institute of Mental Health, Klecany, Czech Republic.,Department of Psychiatry and Medical Psychology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
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12
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Uddin MS, Kabir MT, Jeandet P, Mathew B, Ashraf GM, Perveen A, Bin-Jumah MN, Mousa SA, Abdel-Daim MM. Novel Anti-Alzheimer's Therapeutic Molecules Targeting Amyloid Precursor Protein Processing. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:7039138. [PMID: 32411333 PMCID: PMC7206886 DOI: 10.1155/2020/7039138] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 03/27/2020] [Accepted: 04/01/2020] [Indexed: 02/04/2023]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia among older people, and the prevalence of this disease is estimated to rise quickly in the upcoming years. Unfortunately, almost all of the drug candidates tested for AD until now have failed to exhibit any efficacy. Henceforth, there is an increased necessity to avert and/or slow down the advancement of AD. It is known that one of the major pathological characteristics of AD is the presence of senile plaques (SPs) in the brain. These SPs are composed of aggregated amyloid beta (Aβ), derived from the amyloid precursor protein (APP). Pharmaceutical companies have conducted a number of studies in order to identify safe and effective anti-Aβ drugs to combat AD. It is known that α-, β-, and γ-secretases are the three proteases that are involved in APP processing. Furthermore, there is a growing interest in these proteases, as they have a contribution to the modulation and production of Aβ. It has been observed that small compounds can be used to target these important proteases. Indeed, these compounds must satisfy the common strict requirements of a drug candidate targeted for brain penetration and selectivity toward different proteases. In this article, we have focused on the auspicious molecules which are under development for targeting APP-processing enzymes. We have also presented several anti-AD molecules targeting Aβ accumulation and phosphorylation signaling in APP processing. This review highlights the structure-activity relationship and other physicochemical features of several pharmacological candidates in order to successfully develop new anti-AD drugs.
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Affiliation(s)
- Md. Sahab Uddin
- Department of Pharmacy, Southeast University, Dhaka, Bangladesh
- Pharmakon Neuroscience Research Network, Dhaka, Bangladesh
| | | | - Philippe Jeandet
- Research Unit, Induced Resistance and Plant Bioprotection, EA 4707, SFR Condorcet FR CNRS 3417, Faculty of Sciences, University of Reims Champagne-Ardenne, PO Box 1039, 51687 Reims Cedex 2, France
| | - Bijo Mathew
- Division of Drug Design and Medicinal Chemistry Research Lab, Department of Pharmaceutical Chemistry, Ahalia School of Pharmacy, Palakkad, India
| | - Ghulam Md Ashraf
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Asma Perveen
- Glocal School of Life Sciences, Glocal University, Saharanpur, India
| | - May N. Bin-Jumah
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh 11474, Saudi Arabia
| | - Shaker A. Mousa
- Pharmaceutical Research Institute, Albany College of Pharmacy and Health Sciences, New York, NY 12144, USA
| | - Mohamed M. Abdel-Daim
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
- Pharmacology Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia 41522, Egypt
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13
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Alam J, Sharma L. Potential Enzymatic Targets in Alzheimer's: A Comprehensive Review. Curr Drug Targets 2020; 20:316-339. [PMID: 30124150 DOI: 10.2174/1389450119666180820104723] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/23/2018] [Accepted: 08/15/2018] [Indexed: 12/13/2022]
Abstract
Alzheimer's, a degenerative cause of the brain cells, is called as a progressive neurodegenerative disease and appears to have a heterogeneous etiology with main emphasis on amyloid-cascade and hyperphosphorylated tau-cascade hypotheses, that are directly linked with macromolecules called enzymes such as β- & γ-secretases, colinesterases, transglutaminases, and glycogen synthase kinase (GSK-3), cyclin-dependent kinase (cdk-5), microtubule affinity-regulating kinase (MARK). The catalytic activity of the above enzymes is the result of cognitive deficits, memory impairment and synaptic dysfunction and loss, and ultimately neuronal death. However, some other enzymes also lead to these dysfunctional events when reduced to their normal activities and levels in the brain, such as α- secretase, protein kinase C, phosphatases etc; metabolized to neurotransmitters, enzymes like monoamine oxidase (MAO), catechol-O-methyltransferase (COMT) etc. or these abnormalities can occur when enzymes act by other mechanisms such as phosphodiesterase reduces brain nucleotides (cGMP and cAMP) levels, phospholipase A2: PLA2 is associated with reactive oxygen species (ROS) production etc. On therapeutic fronts, several significant clinical trials are underway by targeting different enzymes for development of new therapeutics to treat Alzheimer's, such as inhibitors for β-secretase, GSK-3, MAO, phosphodiesterase, PLA2, cholinesterases etc, modulators of α- & γ-secretase activities and activators for protein kinase C, sirtuins etc. The last decades have perceived an increasing focus on findings and search for new putative and novel enzymatic targets for Alzheimer's. Here, we review the functions, pathological roles, and worth of almost all the Alzheimer's associated enzymes that address to therapeutic strategies and preventive approaches for treatment of Alzheimer's.
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Affiliation(s)
- Jahangir Alam
- School of Pharmaceutical Sciences, Shoolini University, Solan, H.P., Pin 173229, India
| | - Lalit Sharma
- School of Pharmaceutical Sciences, Shoolini University, Solan, H.P., Pin 173229, India
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14
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Familial Alzheimer's disease patient-derived neurons reveal distinct mutation-specific effects on amyloid beta. Mol Psychiatry 2020; 25:2919-2931. [PMID: 30980041 PMCID: PMC7577860 DOI: 10.1038/s41380-019-0410-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 01/04/2019] [Accepted: 03/18/2019] [Indexed: 02/07/2023]
Abstract
Familial Alzheimer's disease (fAD) mutations alter amyloid precursor protein (APP) cleavage by γ-secretase, increasing the proportion of longer amyloidogenic amyloid-β (Aβ) peptides. Using five control induced pluripotent stem cell (iPSC) lines and seven iPSC lines generated from fAD patients, we investigated the effects of mutations on the Aβ secretome in human neurons generated in 2D and 3D. We also analysed matched CSF, post-mortem brain tissue, and iPSCs from the same participant with the APP V717I mutation. All fAD mutation lines demonstrated an increased Aβ42:40 ratio relative to controls, yet displayed varied signatures for Aβ43, Aβ38, and short Aβ fragments. We propose four qualitatively distinct mechanisms behind raised Aβ42:40. (1) APP V717I mutations alter γ-secretase cleavage site preference. Whereas, distinct presenilin 1 (PSEN1) mutations lead to either (2) reduced γ-secretase activity, (3) altered protein stability or (4) reduced PSEN1 maturation, all culminating in reduced γ-secretase carboxypeptidase-like activity. These data support Aβ mechanistic tenets in a human physiological model and substantiate iPSC-neurons for modelling fAD.
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15
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Webers A, Heneka MT, Gleeson PA. The role of innate immune responses and neuroinflammation in amyloid accumulation and progression of Alzheimer's disease. Immunol Cell Biol 2019; 98:28-41. [PMID: 31654430 DOI: 10.1111/imcb.12301] [Citation(s) in RCA: 203] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/20/2019] [Accepted: 10/24/2019] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD) is characterized by amyloid beta (Aβ) accumulation, tau pathology and neuroinflammation. Recently, there has been considerable interest in the role of neuroinflammation in directly contributing to the progression of AD. Studies in mice and humans have identified a role for microglial cells, the resident innate immune cells of the central nervous system, in AD. Activated microglia are a key hallmark of the disease and the secretion of proinflammatory cytokines by microglia may result in a positive feedback loop between neurons and microglia, resulting in ongoing low-grade inflammation. Traditionally, the pathways of Aβ production and neuroinflammation have been considered independently; however, recent studies suggest that these processes may converge to promote the pathology associated with AD. Here we review the importance of inflammation and microglia in AD development and effects of inflammatory responses on cellular pathways of neurons, including Aβ generation.
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Affiliation(s)
- Alessandra Webers
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia.,Department of Neurodegenerative Disease and Geriatric Psychiatry, University of Bonn, Bonn, Germany
| | - Michael T Heneka
- Department of Neurodegenerative Disease and Geriatric Psychiatry, University of Bonn, Bonn, Germany.,German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Paul A Gleeson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
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16
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Won JH, Kim GW, Kim JY, Cho DG, Kwon B, Bae YK, Cho KO. ADAMTS Sol narae cleaves extracellular Wingless to generate a novel active form that regulates cell proliferation in Drosophila. Cell Death Dis 2019; 10:564. [PMID: 31332194 PMCID: PMC6646336 DOI: 10.1038/s41419-019-1794-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 06/14/2019] [Accepted: 07/04/2019] [Indexed: 11/23/2022]
Abstract
Wnt/ Wingless (Wg) is essential for embryonic development and adult homeostasis in all metazoans, but the mechanisms by which secreted Wnt/Wg is processed remain largely unknown. A Drosophila Sol narae (Sona) is a member of ADisintegrin And Metalloprotease with ThromboSpondin motif (ADAMTS) family, and positively regulates Wg signaling by promoting Wg secretion. Here we report that Sona and Wg are secreted by both conventional Golgi and exosomal transports, and Sona cleaves extracellular Wg at the two specific sites, leading to the generation of N-terminal domain (NTD) and C-terminal domain (CTD) fragments. The cleaved forms of extracellular Wg were detected in the extracellular region of fly wing discs, and its level was substantially reduced in sona mutants. Transient overexpression of Wg-CTD increased wing size while prolonged overexpression caused lethality and developmental defects. In contrast, Wg-NTD did not induce any phenotype. Moreover, the wing defects and lethality induced by sona RNAi were considerably rescued by Wg-CTD, indicating that a main function of extracellular Sona is the generation of Wg-CTD. Wg-CTD stabilized cytoplasmic Armadillo (Arm) and had genetic interactions with components of canonical Wg signaling. Wg-CTD also induced Wg downstream targets such as Distal-less (Dll) and Vestigial (Vg). Most importantly, Cyclin D (Cyc D) was induced by Wg-CTD but not by full-length Wg. Because Sona also induces Cyc D in a cell non-autonomous manner, Wg-CTD generated by Sona in the extracellular region activates a subset of Wg signaling whose major function is the regulation of cell proliferation.
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Affiliation(s)
- Jong-Hoon Won
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, Korea
| | - Go-Woon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, Korea
| | - Ja-Young Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, Korea
| | - Dong-Gyu Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, Korea
| | - Buki Kwon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, Korea
| | - Young-Kyung Bae
- Center for Bioanalysis, Korea Research Institute of Standards and Science, 267 Gajung-ro, Yuseung-gu, Daejeon, Korea
| | - Kyung-Ok Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, Korea.
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17
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Zhao L, Zhao Y, Tang FL, Xiong L, Su C, Mei L, Zhu XJ, Xiong WC. pHluorin-BACE1-mCherry Acts as a Reporter for the Intracellular Distribution of Active BACE1 In Vitro and In Vivo. Cells 2019; 8:E474. [PMID: 31108937 PMCID: PMC6562731 DOI: 10.3390/cells8050474] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/09/2019] [Accepted: 05/15/2019] [Indexed: 12/23/2022] Open
Abstract
β-site APP-cleaving enzyme 1 (BACE1) initiates amyloid precursor protein (APP) cleavage and β-amyloid (Aβ) production, a critical step in the pathogenesis of Alzheimer's disease (AD). It is thus of considerable interest to investigate how BACE1 activity is regulated. BACE1 has its maximal activity at acidic pH and GFP variant-pHluorin-displays pH dependence. In light of these observations, we generated three tandem fluorescence-tagged BACE1 fusion proteins, named pHluorin-BACE1-mCherry, BACE1-mCherry-pHluorin and BACE1-mCherry-EGFP. Comparing the fluorescence characteristics of these proteins in response to intracellular pH changes induced by chloroquine or bafilomycin A1, we found that pHluorin-BACE1-mCherry is a better pH sensor for BACE1 because its fluorescence intensity responds to pH changes more dramatically and more quickly. Additionally, we found that (pro)renin receptor (PRR), a subunit of the v-ATPase complex, which is critical for maintaining vesicular pH, regulates pHluorin's fluorescence and BACE1 activity in pHluorin-BACE1-mCherry expressing cells. Finally, we found that the expression of Swedish mutant APP (APPswe) suppresses pHluorin fluorescence in pHluorin-BACE1-mCherry expressing cells in culture and in vivo, implicating APPswe not only as a substrate but also as an activator of BACE1. Taken together, these results suggest that the pHluorin-BACE1-mCherry fusion protein may serve as a useful tool for visualizing active/inactive BACE1 in culture and in vivo.
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Affiliation(s)
- Lu Zhao
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China.
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
| | - Yang Zhao
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China.
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Fu-Lei Tang
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
| | - Lei Xiong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
| | - Ce Su
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China.
| | - Lin Mei
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
| | - Xiao-Juan Zhu
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Institute of Cytology and Genetics, Northeast Normal University, Changchun 130024, China.
| | - Wen-Cheng Xiong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA.
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18
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Gómez-Pinedo U, Galán L, Matías-Guiu JA, Pytel V, Moreno T, Guerrero-Sola A, Matías-Guiu J. Notch Signalling in the Hippocampus of Patients With Motor Neuron Disease. Front Neurosci 2019; 13:302. [PMID: 31024234 PMCID: PMC6460507 DOI: 10.3389/fnins.2019.00302] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/15/2019] [Indexed: 12/12/2022] Open
Abstract
Introduction The Notch signalling pathway regulates neuronal survival. It has some similarities with the APP signalling pathway, and competes with the latter for α- and γ-secretase proteolytic complexes. The objective of this study was to study the Notch signalling pathway in the hippocampi of patients with motor neuron disease. Methods We studied biological material from the autopsies of 12 patients with motor neuron disease and 4 controls. We analysed the molecular markers of the Notch and APP signalling pathways, TDP43, tau, and markers of neurogenesis. Results and Conclusion Low NICD expression suggests Notch signalling pathway inactivation in neurons. Inactivation of the pathway despite increased Notch1 expression is associated with a lack of α-secretase expression. We observed increased β-secretase expression associated with activation of the amyloid cascade of APP, leading to increases in amyloid-β and AICD peptides and decreased levels of Fe65. Inactivation of the Notch signalling pathway is an important factor in decreased neurogenic response in the hippocampi of patients with amyotrophic lateral sclerosis.
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Affiliation(s)
- Ulises Gómez-Pinedo
- Laboratory of Neurobiology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - Lucía Galán
- Department of Neurology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - Jordi A Matías-Guiu
- Department of Neurology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - Vanesa Pytel
- Laboratory of Neurobiology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain.,Department of Neurology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - Teresa Moreno
- Department of Neurology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - Antonio Guerrero-Sola
- Department of Neurology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
| | - Jorge Matías-Guiu
- Laboratory of Neurobiology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain.,Department of Neurology, Institute of Neurosciences, IdISSC, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain
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19
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Wang X, Pei G. Visualization of Alzheimer's Disease Related α-/β-/γ-Secretase Ternary Complex by Bimolecular Fluorescence Complementation Based Fluorescence Resonance Energy Transfer. Front Mol Neurosci 2018; 11:431. [PMID: 30538620 PMCID: PMC6277482 DOI: 10.3389/fnmol.2018.00431] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/05/2018] [Indexed: 11/13/2022] Open
Abstract
The competitive ectodomain shedding of amyloid-β precursor protein (APP) by α-secretase and β-secretase, and the subsequent regulated intramembrane proteolysis by γ-secretase are the key processes in amyloid-β peptides (Aβ) generation. Previous studies indicate that secretases form binary complex and the interactions between secretases take part in substrates processing. However, whether α-, β- and γ-secretase could form ternary complex remains to be explored. Here, we adopted bimolecular fluorescence complementation in combination with fluorescence resonance energy transfer (BiFC-FRET) to visualize the formation of triple secretase complex. We show that the interaction between α-secretase ADAM10 and β-secretase BACE1 could be monitored by BiFC assay and the binding of APP to α-/β-secretase binary complex was revealed by BiFC-FRET. Further, we observed that γ-secretase interacts with α-/β-secretase binary complex, providing evidence that α-, β- and γ-secretase might form a ternary complex. Thus our study extends the interplay among Alzheimer's disease (AD) related α-/β-/γ-secretase.
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Affiliation(s)
- Xin Wang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Gang Pei
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, and The Collaborative Innovation Center for Brain Science, Tongji University, Shanghai, China
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20
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Scholz D, Chernyshova Y, Ückert AK, Leist M. Reduced Aβ secretion by human neurons under conditions of strongly increased BACE activity. J Neurochem 2018; 147:256-274. [PMID: 29804308 DOI: 10.1111/jnc.14467] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 05/06/2018] [Accepted: 05/23/2018] [Indexed: 12/20/2022]
Abstract
The initial step in the amyloidogenic cascade of amyloid precursor protein (APP) processing is catalyzed by beta-site APP-cleaving enzyme (BACE), and this protease has increased activities in affected areas of Alzheimer's disease brains. We hypothesized that altered APP processing, because of augmented BACE activity, would affect the actions of direct and indirect BACE inhibitors. We therefore compared post-mitotic human neurons (LUHMES) with their BACE-overexpressing counterparts (BLUHMES). Although β-cleavage of APP was strongly increased in BLUHMES, they produced less full-length and truncated amyloid beta (Aβ) than LUHMES. Moreover, low concentrations of BACE inhibitors decreased cellular BACE activity as expected, but increased Aβ1-40 levels. Several other approaches to modulate BACE activity led to a similar, apparently paradoxical, behavior. For instance, reduction in intracellular acidification by bepridil increased Aβ production in parallel with decreased BACE activity. In contrast to BLUHMES, the respective control cells (LUHMES or BLUHMES with catalytically inactive BACE) showed conventional pharmacological responses. Other non-canonical neurochemical responses (so-called 'rebound effects') are well-documented for the Aβ pathway, especially for γ-secretase: a partial block of its activity leads to an increased Aβ secretion by some cell types. We therefore compared LUHMES and BLUHMES regarding rebound effects of γ-secretase inhibitors and found an Aβ rise in LUHMES but not in BLUHMES. Thus, different cellular factors are responsible for the γ-secretase- versus BACE-related Aβ rebound. We conclude that increased BACE activity, possibly accompanied by an altered cellular localization pattern, can dramatically influence Aβ generation in human neurons and affect pharmacological responses to secretase inhibitors. OPEN PRACTICES: Open Science: This manuscript was awarded with the Open Materials Badge. For more information see: https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Diana Scholz
- Chair for in vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - Yana Chernyshova
- Chair for in vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - Anna-Katharina Ückert
- Chair for in vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - Marcel Leist
- Chair for in vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
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21
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Du Y, Zhao Y, Li C, Zheng Q, Tian J, Li Z, Huang TY, Zhang W, Xu H. Inhibition of PKCδ reduces amyloid-β levels and reverses Alzheimer disease phenotypes. J Exp Med 2018; 215:1665-1677. [PMID: 29739836 PMCID: PMC5987914 DOI: 10.1084/jem.20171193] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 01/11/2018] [Accepted: 03/29/2018] [Indexed: 12/28/2022] Open
Abstract
β-amyloid protein (Aβ) plays a central role in the pathogenesis of Alzheimer disease (AD). Aβ is generated from sequential cleavage of amyloid precursor protein (APP) by β-site APP-cleaving enzyme 1 (BACE1) and the γ-secretase complex. Although activation of some protein kinase C (PKC) isoforms such as PKCα and ε has been shown to regulate nonamyloidogenic pathways and Aβ degradation, it is unclear whether other PKC isoforms are involved in APP processing/AD pathogenesis. In this study, we report that increased PKCδ levels correlate with BACE1 expression in the AD brain. PKCδ knockdown reduces BACE1 expression, BACE1-mediated APP processing, and Aβ production. Conversely, overexpression of PKCδ increases BACE1 expression and Aβ generation. Importantly, inhibition of PKCδ by rottlerin markedly reduces BACE1 expression, Aβ levels, and neuritic plaque formation and rescues cognitive deficits in an APP Swedish mutations K594N/M595L/presenilin-1 with an exon 9 deletion-transgenic AD mouse model. Our study indicates that PKCδ plays an important role in aggravating AD pathogenesis, and PKCδ may be a potential target in AD therapeutics.
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Affiliation(s)
- Ying Du
- Department of Neurology, Tangdu Hospital, Fourth Military Medical University, Xian, China
| | - Yingjun Zhao
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Chuan Li
- Department of Neurology, Tangdu Hospital, Fourth Military Medical University, Xian, China
| | - Qiuyang Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, The Collaborative Innovation Center for Brain Science, Medical College, Xiamen University, Xiamen, China
| | - Jing Tian
- College of Life Sciences and Oceanography, Shenzhen Key Laboratory of Marine Bioresources and Eco-Environmental Science, Shenzhen University, Shenzhen, China
| | - Zhuyi Li
- Department of Neurology, Tangdu Hospital, Fourth Military Medical University, Xian, China
| | - Timothy Y Huang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Wei Zhang
- Department of Neurology, Tangdu Hospital, Fourth Military Medical University, Xian, China
| | - Huaxi Xu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA.,Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, The Collaborative Innovation Center for Brain Science, Medical College, Xiamen University, Xiamen, China
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22
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Meakin PJ, Mezzapesa A, Benabou E, Haas ME, Bonardo B, Grino M, Brunel JM, Desbois-Mouthon C, Biddinger SB, Govers R, Ashford MLJ, Peiretti F. The beta secretase BACE1 regulates the expression of insulin receptor in the liver. Nat Commun 2018; 9:1306. [PMID: 29610518 PMCID: PMC5880807 DOI: 10.1038/s41467-018-03755-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 03/08/2018] [Indexed: 01/04/2023] Open
Abstract
Insulin receptor (IR) plays a key role in the control of glucose homeostasis; however, the regulation of its cellular expression remains poorly understood. Here we show that the amount of biologically active IR is regulated by the cleavage of its ectodomain, by the β-site amyloid precursor protein cleaving enzyme 1 (BACE1), in a glucose concentration-dependent manner. In vivo studies demonstrate that BACE1 regulates the amount of IR and insulin signaling in the liver. During diabetes, BACE1-dependent cleavage of IR is increased and the amount of IR in the liver is reduced, whereas infusion of a BACE1 inhibitor partially restores liver IR. We suggest the potential use of BACE1 inhibitors to enhance insulin signaling during diabetes. Additionally, we show that plasma levels of cleaved IR reflect IR isoform A expression levels in liver tumors, which prompts us to propose that the measurement of circulating cleaved IR may assist hepatic cancer detection and management.
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Affiliation(s)
- Paul J Meakin
- Division of Molecular & Clinical Medicine, Ninewells Hospital & Medical School, Dundee, DD19SY, UK
| | - Anna Mezzapesa
- Aix Marseille Univ, INSERM, INRA, C2VN, 13385, Marseille, France
| | - Eva Benabou
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Saint-Antoine Research Center, F-75012, Paris, France
| | - Mary E Haas
- Division of Endocrinology, Boston Children's Hospital, Boston, MA, 02115, USA
| | | | - Michel Grino
- Aix Marseille Univ, INSERM, INRA, C2VN, 13385, Marseille, France
| | - Jean-Michel Brunel
- Aix Marseille Univ, INSERM, CNRS, CRCM, Institut Paoli Calmettes, Marseille, 13385, France
| | - Christèle Desbois-Mouthon
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Saint-Antoine Research Center, F-75012, Paris, France
| | - Sudha B Biddinger
- Division of Endocrinology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Roland Govers
- Aix Marseille Univ, INSERM, INRA, C2VN, 13385, Marseille, France
| | - Michael L J Ashford
- Division of Molecular & Clinical Medicine, Ninewells Hospital & Medical School, Dundee, DD19SY, UK
| | - Franck Peiretti
- Aix Marseille Univ, INSERM, INRA, C2VN, 13385, Marseille, France.
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23
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Saadipour K, Mañucat-Tan NB, Lim Y, Keating DJ, Smith KS, Zhong JH, Liao H, Bobrovskaya L, Wang YJ, Chao MV, Zhou XF. p75 neurotrophin receptor interacts with and promotes BACE1 localization in endosomes aggravating amyloidogenesis. J Neurochem 2018; 144:302-317. [PMID: 28869759 DOI: 10.1111/jnc.14206] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 07/17/2017] [Accepted: 08/29/2017] [Indexed: 12/27/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a progressive deposition of amyloid beta (Aβ) and dysregulation of neurotrophic signaling, causing synaptic dysfunction, loss of memory, and cell death. The expression of p75 neurotrophin receptor is elevated in the brain of AD patients, suggesting its involvement in this disease. However, the exact mechanism of its action is not yet clear. Here, we show that p75 interacts with beta-site amyloid precursor protein cleaving enzyme-1 (BACE1), and this interaction is enhanced in the presence of Aβ. Our results suggest that the colocalization of BACE1 and amyloid precursor protein (APP) is increased in the presence of both Aβ and p75 in cortical neurons. In addition, the localization of APP and BACE1 in early endosomes is increased in the presence of Aβ and p75. An increased phosphorylation of APP-Thr668 and BACE1-Ser498 by c-Jun N-terminal kinase (JNK) in the presence of Aβ and p75 could be responsible for this localization. In conclusion, our study proposes a potential involvement in amyloidogenesis for p75, which may represent a future therapeutic target for AD. Cover Image for this Issue: doi. 10.1111/jnc.14163.
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Affiliation(s)
- Khalil Saadipour
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia
- Department of Human Physiology, Centre for Neuroscience, Flinders University, Adelaide, South Australia
- Departments of Cell Biology, Physiology & Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone School of Medicine, New York, NY, USA
| | - Noralyn B Mañucat-Tan
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia
| | - Yoon Lim
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia
| | - Damien J Keating
- Department of Human Physiology, Centre for Neuroscience, Flinders University, Adelaide, South Australia
| | - Kevin S Smith
- Department of Human Physiology, Centre for Neuroscience, Flinders University, Adelaide, South Australia
| | - Jin-Hua Zhong
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia
| | - Hong Liao
- New Drug Screening Centre, China Pharmaceutical University, Nanjing, China
| | - Larisa Bobrovskaya
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia
| | - Yan-Jiang Wang
- Department of Neurology and Center for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Moses V Chao
- Departments of Cell Biology, Physiology & Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone School of Medicine, New York, NY, USA
| | - Xin-Fu Zhou
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia
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24
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Bittner HJ, Guixà-González R, Hildebrand PW. Structural basis for the interaction of the beta-secretase with copper. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1105-1113. [PMID: 29391167 DOI: 10.1016/j.bbamem.2018.01.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 01/21/2018] [Accepted: 01/23/2018] [Indexed: 12/18/2022]
Abstract
The β-secretase (BACE1) features a unique sulfur rich motif (M462xxxC466xxxM470xxxC474xxxC478) in its transmembrane helix (BACE1-TM) which is characteristic for proteins involved in copper ion storage and transport. While this motif has been shown to promote BACE1-TM trimerization and binding of copper ions in vitro, the structural basis for the interaction of copper ions with the BACE1-TM is still not well understood. Using molecular dynamics (MD) simulations, we show that membrane embedded BACE1-TMs adopt a flexible trimeric structure that binds and conducts copper ions through variable coordination. In coarse-grained (CG) MD simulations, the spontaneous assembly of BACE1-TMs trimers results in a right-handed helix packing arrangement. In subsequent atomistic MD simulations the sulfur rich motif defines characteristic copper ion coordination sites along a constricted partially solvated axial pore. Sliding and tilting of BACE1-TMs along smooth A459xxxA463/464xxA467 surfaces, facilitated by a central P472 induced kink, enables copper ions to alternate between different coordination sites, including the prominent C466 and M470. We shed light into the structural arrangement of BACE1-TM trimers and propose a mechanism for copper ion conduction that might also apply to other proteins involved in metal ion transport.
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Affiliation(s)
- Heiko J Bittner
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Medical Physics and Biophysics {Institut für Medizinische Physik und Biophysik}, AG ProteInFormatics, Charitéplatz 1, 10117 Berlin, Germany; Faculty of Medicine, Leipzig University, Institute for Medical Physics and Biophysics {Institut für Medizinische Physik und Biophysik}, Härtelstr. 16-18, 04107 Leipzig, Germany.
| | - Ramon Guixà-González
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Medical Physics and Biophysics {Institut für Medizinische Physik und Biophysik}, AG ProteInFormatics, Charitéplatz 1, 10117 Berlin, Germany.
| | - Peter W Hildebrand
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Medical Physics and Biophysics {Institut für Medizinische Physik und Biophysik}, AG ProteInFormatics, Charitéplatz 1, 10117 Berlin, Germany; Faculty of Medicine, Leipzig University, Institute for Medical Physics and Biophysics {Institut für Medizinische Physik und Biophysik}, Härtelstr. 16-18, 04107 Leipzig, Germany.
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25
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Sun J, Roy S. The physical approximation of APP and BACE-1: A key event in alzheimer's disease pathogenesis. Dev Neurobiol 2017; 78:340-347. [PMID: 29106038 DOI: 10.1002/dneu.22556] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 10/17/2017] [Accepted: 11/01/2017] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of insoluble deposits of Amyloid β (Aβ) in brains. Aβ is derived by sequential cleavage of the amyloid precursor protein (APP) by β-site secretase enzyme (BACE-1) and γ-secretase. Proteolytic processing of APP by BACE-1 is the rate-limiting step in Aβ production, and this pathway is a prime target for AD drug development. Both APP and BACE-1 are membrane-spanning proteins, transported via secretory and endocytic pathways; and the physical interaction of APP and BACE-1 during trafficking is a key cell biological event initiating the amyloidogenic pathway. Here, we highlight recent research on intracellular trafficking/sorting of APP and BACE-1, and discuss how dysregulation of these pathways might lead to enhanced convergence of APP and BACE-1, and subsequent β-cleavage of APP. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 78: 340-347, 2018.
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Affiliation(s)
- Jichao Sun
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin, 53705.,Department of Neuroscience, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin, 53705
| | - Subhojit Roy
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin, 53705.,Department of Neuroscience, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin, 53705
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26
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Brandimarti R, Hill GS, Geiger JD, Meucci O. The lipid raft-dwelling protein US9 can be manipulated to target APP compartmentalization, APP processing, and neurodegenerative disease pathogenesis. Sci Rep 2017; 7:15103. [PMID: 29118375 PMCID: PMC5678071 DOI: 10.1038/s41598-017-15128-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 10/20/2017] [Indexed: 01/13/2023] Open
Abstract
The trafficking behavior of the lipid raft-dwelling US9 protein from Herpes Simplex Virus strikingly overlaps with that of the amyloid precursor protein (APP). Both US9 and APP processing machinery rely on their ability to shuttle between endosomes and plasma membranes, as well as on their lateral accumulation in lipid rafts. Therefore, repurposing US9 to track/modify these molecular events represents a valid approach to investigate pathological states including Alzheimer's disease and HIV-associated neurocognitive disorders where APP misprocessing to amyloid beta formation has been observed. Accordingly, we investigated the cellular localization of US9-driven cargo in neurons and created a US9-driven functional assay based on the exogenous enzymatic activity of Tobacco Etch Virus Protease. Our results demonstrate that US9 can direct and control cleavage of recombinant proteins exposed on the luminal leaflet of transport vesicles. Furthermore, we confirmed that US9 is associated with lipid-rafts and can target functional enzymes to membrane microdomains where pathologic APP-processing is thought to occur. Overall, our results suggest strongly that US9 can serve as a molecular driver that targets functional cargos to the APP machinery and can be used as a tool to study the contribution of lipid rafts to neurodegenerative disease conditions where amyloidogenesis has been implicated.
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Affiliation(s)
- Renato Brandimarti
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia (PA), USA.
- Department of Pharmacy and Biotechnologies, Alma Mater Studiorum, University of Bologna, Bologna, Italy.
| | - Gordon S Hill
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia (PA), USA
| | - Jonathan D Geiger
- Department of Basic Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks (ND), USA
| | - Olimpia Meucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia (PA), USA.
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia (PA), USA.
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27
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Hou H, Fan Q, He W, Suh H, Hu X, Yan R. BACE1 Deficiency Causes Abnormal Neuronal Clustering in the Dentate Gyrus. Stem Cell Reports 2017; 9:217-230. [PMID: 28669600 PMCID: PMC5511112 DOI: 10.1016/j.stemcr.2017.05.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 12/04/2022] Open
Abstract
BACE1 is validated as Alzheimer's β-secretase and a therapeutic target for Alzheimer's disease. In examining BACE1-null mice, we discovered that BACE1 deficiency develops abnormal clusters of immature neurons, forming doublecortin-positive neuroblasts, in the developing dentate gyrus, mainly in the subpial zone (SPZ). Such clusters were rarely observed in wild-type SPZ and not reported in other mouse models. To understand their origins and fates, we examined how neuroblasts in BACE1-null SPZ mature and migrate during early postnatal development. We show that such neuroblasts are destined to form Prox1-positive granule cells in the dentate granule cell layer, and mainly mature to form excitatory neurons, but not inhibitory neurons. Mechanistically, higher levels of reelin potentially contribute to abnormal neurogenesis and timely migration in BACE1-null SPZ. Altogether, we demonstrate that BACE1 is a critical regulator in forming the dentate granule cell layer through timely maturation and migration of SPZ neuroblasts. BACE1 deficiency causes abnormal neuronal clusters retained in the mouse SPZ Mis-migrated neural progenitor cells in the SPZ are destined to form granule cells Such neural progenitor cells form excitatory neurons but not inhibitor neurons Elevated levels of reelin contribute to abnormal neuronal maturation and migration
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Affiliation(s)
- Hailong Hou
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue/NC30, Cleveland, OH 44195, USA
| | - Qingyuan Fan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue/NC30, Cleveland, OH 44195, USA
| | - Wanxia He
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue/NC30, Cleveland, OH 44195, USA
| | - Hoonkyo Suh
- Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Xiangyou Hu
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue/NC30, Cleveland, OH 44195, USA
| | - Riqiang Yan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue/NC30, Cleveland, OH 44195, USA.
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28
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Alsaqati M, Thomas RS, Kidd EJ. Proteins Involved in Endocytosis Are Upregulated by Ageing in the Normal Human Brain: Implications for the Development of Alzheimer’s Disease. J Gerontol A Biol Sci Med Sci 2017; 73:289-298. [DOI: 10.1093/gerona/glx135] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 06/25/2017] [Indexed: 12/13/2022] Open
Affiliation(s)
- Mouhamed Alsaqati
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, UK
- Neuroscience and Mental Health Research Institute, Cardiff University, UK
| | - Rhian S Thomas
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, UK
- Department of Applied Sciences, Faculty of Health and Applied Sciences, University of the West of England, Bristol, UK
| | - Emma J Kidd
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, UK
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29
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Dysregulation of intracellular trafficking and endosomal sorting in Alzheimer's disease: controversies and unanswered questions. Biochem J 2017; 473:1977-93. [PMID: 27407168 DOI: 10.1042/bcj20160147] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/18/2016] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of amyloid plaques in the brain consisting of an aggregated form of amyloid β-peptide (Aβ) derived from sequential amyloidogenic processing of the amyloid precursor protein (APP) by membrane-bound proteases β-site APP-cleaving enzyme 1 (BACE1) and γ-secretase. The initial processing of APP by BACE1 is re-gulated by intracellular sorting events of the enzyme, which is a prime target for therapeutic intervention. GWAS (genome-wide sequencing studies) have identified several AD-susceptibility genes that are associated with the regulation of membrane trafficking, and substantial evidence now indicates that AD is likely to arise from defective membrane trafficking in either or both of the secretory and endocytic pathways. Considerable progress has been made in defining the intracellular trafficking pathways of BACE1 and APP and the sorting signals of these membrane proteins that define their itineraries. In this review we highlight recent advances in understanding the regulation of the intracellular sorting of BACE1 and APP, discuss how dysregulation of these trafficking events may lead to enhanced generation of the neurotoxic Aβ products in AD and highlight the unresolved questions in the field.
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30
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Structural Similarities between Neuregulin 1-3 Isoforms Determine Their Subcellular Distribution and Signaling Mode in Central Neurons. J Neurosci 2017; 37:5232-5249. [PMID: 28432142 DOI: 10.1523/jneurosci.2630-16.2017] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 03/14/2017] [Accepted: 04/09/2017] [Indexed: 11/21/2022] Open
Abstract
The Neuregulin (NRG) family of ErbB ligands is comprised of numerous variants originating from the use of different genes, alternative promoters, and splice variants. NRGs have generally been thought to be transported to axons and presynaptic terminals where they signal via ErbB3/4 receptors in paracrine or juxtacrine mode. However, we recently demonstrated that unprocessed pro-NRG2 accumulates on cell bodies and proximal dendrites, and that NMDAR activity is required for shedding of its ectodomain by metalloproteinases. Here we systematically investigated the subcellular distribution and processing of major NRG isoforms in rat hippocampal neurons. We show that NRG1 isotypes I and II, which like NRG2 are single-pass transmembrane proteins with an Ig-like domain, share the same subcellular distribution and ectodomain shedding properties. We furthermore show that NRG3, like CRD-NRG1, is a dual-pass transmembrane protein that harbors a second transmembrane domain near its amino terminus. Both NRG3 and CRD-NRG1 cluster on axons through juxtacrine interactions with ErbB4 present on GABAergic interneurons. Interestingly, although single-pass NRGs accumulate as unprocessed proforms, axonal puncta of CRD-NRG1 and NRG3 are comprised of processed protein. Mutations of CRD-NRG1 and NRG3 that render them resistant to BACE cleavage, as well as BACE inhibition, result in the loss of axonal puncta and in the accumulation of unprocessed proforms in neuronal soma. Together, these results define two groups of NRGs with distinct membrane topologies and fundamentally different targeting and processing properties in central neurons. The implications of this functional diversity for the regulation of neuronal processes by the NRG/ErbB pathway are discussed.SIGNIFICANCE STATEMENT Numerous Neuregulins (NRGs) are generated through the use of different genes, promoters, and alternative splicing, but the functional significance of this evolutionary conserved diversity remains poorly understood. Here we show that NRGs can be categorized by their membrane topologies. Single-pass NRGs, such as NRG1 Types I/II and NRG2, accumulate as unprocessed proforms on cell bodies, and their ectodomains are shed by metalloproteinases in response to NMDA receptor activation. By contrast, dual-pass CRD-NRG1 and NRG3 are constitutively processed by BACE and accumulate on axons where they interact with ErbB4 in juxtacrine mode. These findings reveal a previously unknown functional relationship between membrane topology, protein processing, and subcellular distribution, and suggest that single- and dual-pass NRGs regulate neuronal functions in fundamentally different ways.
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31
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Yan R. Physiological Functions of the β-Site Amyloid Precursor Protein Cleaving Enzyme 1 and 2. Front Mol Neurosci 2017; 10:97. [PMID: 28469554 PMCID: PMC5395628 DOI: 10.3389/fnmol.2017.00097] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 03/22/2017] [Indexed: 01/18/2023] Open
Abstract
BACE1 was discovered as the β-secretase for initiating the cleavage of amyloid precursor protein (APP) at the β-secretase site, while its close homology BACE2 cleaves APP within the β-amyloid (Aβ) domain region and shows distinct cleavage preferences in vivo. Inhibition of BACE1 proteolytic activity has been confirmed to decrease Aβ generation and amyloid deposition, and thus specific inhibition of BACE1 by small molecules is a current focus for Alzheimer’s disease therapy. While BACE1 inhibitors are being tested in advanced clinical trials, knowledge regarding the properties and physiological functions of BACE is highly important and this review summarizes advancements in BACE1 research over the past several years. We and others have shown that BACE1 is not only a critical enzyme for testing the “Amyloid Hypothesis” associated with Alzheimer’s pathogenesis, but also important for various functions such as axon growth and pathfinding, astrogenesis, neurogenesis, hyperexcitation, and synaptic plasticity. BACE2 appears to play different roles such as glucose homeostasis and pigmentation. This knowledge regarding BACE1 functions is critical for monitoring the safe use of BACE1 inhibitors in humans.
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Affiliation(s)
- Riqiang Yan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, ClevelandOH, USA
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32
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Hu X, Hou H, Bastian C, He W, Qiu S, Ge Y, Yin X, Kidd GJ, Brunet S, Trapp BD, Baltan S, Yan R. BACE1 regulates the proliferation and cellular functions of Schwann cells. Glia 2017; 65:712-726. [PMID: 28191691 DOI: 10.1002/glia.23122] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 12/16/2016] [Accepted: 01/18/2017] [Indexed: 12/31/2022]
Abstract
BACE1 is an indispensable enzyme for generating β-amyloid peptides, which are excessively accumulated in brains of Alzheimer's patients. However, BACE1 is also required for proper myelination of peripheral nerves, as BACE1-null mice display hypomyelination. To determine the precise effects of BACE1 on myelination, here we have uncovered a role of BACE1 in the control of Schwann cell proliferation during development. We demonstrate that BACE1 regulates the cleavage of Jagged-1 and Delta-1, two membrane-bound ligands of Notch. BACE1 deficiency induces elevated Jag-Notch signaling activity, which in turn facilitates proliferation of Schwann cells. This increase in proliferation leads to shortened internodes and decreased Schmidt-Lanterman incisures. Functionally, evoked compound action potentials in BACE1-null nerves were significantly smaller and slower, with a clear decrease in excitability. BACE1-null nerves failed to effectively use lactate as an alternative energy source under conditions of increased physiological activity. Correlatively, BACE1-null mice showed reduced performance on rotarod tests. Collectively, our data suggest that BACE1 deficiency enhances proliferation of Schwann cell due to the elevated Jag1/Delta1-Notch signaling, but fails to myelinate axons efficiently due to impaired the neuregulin1-ErbB signaling, which has been documented.
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Affiliation(s)
- Xiangyou Hu
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195.,Department of Anatomy, Anhui Medical University, Hefei, 230032, Anhui, People's Republic of China
| | - Hailong Hou
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195
| | - Chinthasagar Bastian
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195
| | - Wanxia He
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195
| | - Shupeng Qiu
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195
| | - Yingying Ge
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195
| | - Xinhua Yin
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195
| | - Grahame J Kidd
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195
| | - Sylvain Brunet
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195
| | - Bruce D Trapp
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195
| | - Selva Baltan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195
| | - Riqiang Yan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, 44195
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33
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Abstract
Alzheimer's disease (AD) is the primary cause of dementia in the elderly. It remains incurable and poses a huge socio-economic challenge for developed countries with an aging population. AD manifests by progressive decline in cognitive functions and alterations in behaviour, which are the result of the extensive degeneration of brain neurons. The AD pathogenic mechanism involves the accumulation of amyloid beta peptide (Aβ), an aggregating protein fragment that self-associates to form neurotoxic fibrils that trigger a cascade of cellular events leading to neuronal injury and death. Researchers from academia and the pharmaceutical industry have pursued a rational approach to AD drug discovery and targeted the amyloid cascade. Schemes have been devised to prevent the overproduction and accumulation of Aβ in the brain. The extensive efforts of the past 20 years have been translated into bringing new drugs to advanced clinical trials. The most progressed mechanism-based therapies to date consist of immunological interventions to clear Aβ oligomers, and pharmacological drugs to inhibit the secretase enzymes that produce Aβ, namely β-site amyloid precursor-cleaving enzyme (BACE) and γ-secretase. After giving an update on the development and current status of new AD therapeutics, this review will focus on BACE inhibitors and, in particular, will discuss the prospects of verubecestat (MK-8931), which has reached phase III clinical trials.
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Affiliation(s)
- Genevieve Evin
- Florey Institute of Neuroscience and Mental Health, Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia.
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34
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Matías-Guiu JA, Oreja-Guevara C, Cabrera-Martín MN, Moreno-Ramos T, Carreras JL, Matías-Guiu J. Amyloid Proteins and Their Role in Multiple Sclerosis. Considerations in the Use of Amyloid-PET Imaging. Front Neurol 2016; 7:53. [PMID: 27065425 PMCID: PMC4814935 DOI: 10.3389/fneur.2016.00053] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 03/22/2016] [Indexed: 02/06/2023] Open
Abstract
Thioflavin T derivatives are used in positron-emission tomography (PET) studies to detect amyloid protein deposits in patients with Alzheimer disease. These tracers bind extensively to white matter, which suggests that they may be useful in studies of multiple sclerosis (MS), and that proteins resulting from proteolytic processing of the amyloid precursor protein (APP) may contribute to MS. This article reviews data from both clinical and preclinical studies addressing the role of these proteins, whether they are detected in CSF studies or using PET imaging. APP is widely expressed in demyelinated axons and may have a protective effect in MS and in experimental allergic encephalomyelitis in animals. Several mechanisms associated with this increased expression may affect the degree of remyelination in MS. Amyloid-PET imaging may help determine the degree of demyelination and provide information on the molecular changes linked to APP proteolytic processing experienced by patients with MS.
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Affiliation(s)
- Jordi A Matías-Guiu
- Department of Neurology, Hospital Clínico San Carlos, San Carlos Institute for Health Research (IdISSC), Complutense University of Madrid , Madrid , Spain
| | - Celia Oreja-Guevara
- Department of Neurology, Hospital Clínico San Carlos, San Carlos Institute for Health Research (IdISSC), Complutense University of Madrid , Madrid , Spain
| | - María Nieves Cabrera-Martín
- Department of Nuclear Medicine, Hospital Clínico San Carlos, San Carlos Institute for Health Research (IdISSC), Complutense University of Madrid , Madrid , Spain
| | - Teresa Moreno-Ramos
- Department of Neurology, Hospital Clínico San Carlos, San Carlos Institute for Health Research (IdISSC), Complutense University of Madrid , Madrid , Spain
| | - José Luis Carreras
- Department of Nuclear Medicine, Hospital Clínico San Carlos, San Carlos Institute for Health Research (IdISSC), Complutense University of Madrid , Madrid , Spain
| | - Jorge Matías-Guiu
- Department of Neurology, Hospital Clínico San Carlos, San Carlos Institute for Health Research (IdISSC), Complutense University of Madrid , Madrid , Spain
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35
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Ben Halima S, Mishra S, Raja KMP, Willem M, Baici A, Simons K, Brüstle O, Koch P, Haass C, Caflisch A, Rajendran L. Specific Inhibition of β-Secretase Processing of the Alzheimer Disease Amyloid Precursor Protein. Cell Rep 2016; 14:2127-2141. [PMID: 26923602 DOI: 10.1016/j.celrep.2016.01.076] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 11/09/2015] [Accepted: 01/26/2016] [Indexed: 01/18/2023] Open
Abstract
Development of disease-modifying therapeutics is urgently needed for treating Alzheimer disease (AD). AD is characterized by toxic β-amyloid (Aβ) peptides produced by β- and γ-secretase-mediated cleavage of the amyloid precursor protein (APP). β-secretase inhibitors reduce Aβ levels, but mechanism-based side effects arise because they also inhibit β-cleavage of non-amyloid substrates like Neuregulin. We report that β-secretase has a higher affinity for Neuregulin than it does for APP. Kinetic studies demonstrate that the affinities and catalytic efficiencies of β-secretase are higher toward non-amyloid substrates than toward APP. We show that non-amyloid substrates are processed by β-secretase in an endocytosis-independent manner. Exploiting this compartmentalization of substrates, we specifically target the endosomal β-secretase by an endosomally targeted β-secretase inhibitor, which blocked cleavage of APP but not non-amyloid substrates in many cell systems, including induced pluripotent stem cell (iPSC)-derived neurons. β-secretase inhibitors can be designed to specifically inhibit the Alzheimer process, enhancing their potential as AD therapeutics without undesired side effects.
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Affiliation(s)
- Saoussen Ben Halima
- Systems and Cell Biology of Neurodegeneration, Institute of Regenerative Medicine, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland; Graduate Program in Neuroscience, Neuroscience Center Zurich, 8057 Zurich, Switzerland; Graduate Program of the Zurich Center for Integrative Human Physiology, University of Zurich, 8057 Zurich, Switzerland
| | - Sabyashachi Mishra
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
| | - K Muruga Poopathi Raja
- Department of Physical Chemistry, School of Chemistry, Madurai Kamaraj University, Tamil Nadu 625002, Madurai, India
| | - Michael Willem
- Biomedical Center, Ludwig-Maximilians-University, 81337 Munich, Germany
| | - Antonio Baici
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Kai Simons
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Oliver Brüstle
- Institute of Reconstructive Neurobiology, University of Bonn, 53127 Bonn, Germany; German Center for Neurodegenerative Diseases, 53175 Bonn, Germany; Life & Brain, 53127 Bonn, Germany
| | - Philipp Koch
- Institute of Reconstructive Neurobiology, University of Bonn, 53127 Bonn, Germany
| | - Christian Haass
- Biomedical Center, Ludwig-Maximilians-University, 81337 Munich, Germany; German Center for Neurodegenerative Diseases, 53175 Bonn, Germany; Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Amedeo Caflisch
- Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Lawrence Rajendran
- Systems and Cell Biology of Neurodegeneration, Institute of Regenerative Medicine, University of Zurich, Wagistrasse 12, 8952 Schlieren, Switzerland; Graduate Program in Neuroscience, Neuroscience Center Zurich, 8057 Zurich, Switzerland; Graduate Program of the Zurich Center for Integrative Human Physiology, University of Zurich, 8057 Zurich, Switzerland.
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Gong B, Radulovic M, Figueiredo-Pereira ME, Cardozo C. The Ubiquitin-Proteasome System: Potential Therapeutic Targets for Alzheimer's Disease and Spinal Cord Injury. Front Mol Neurosci 2016; 9:4. [PMID: 26858599 PMCID: PMC4727241 DOI: 10.3389/fnmol.2016.00004] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 01/07/2016] [Indexed: 01/20/2023] Open
Abstract
The ubiquitin-proteasome system (UPS) is a crucial protein degradation system in eukaryotes. Herein, we will review advances in the understanding of the role of several proteins of the UPS in Alzheimer’s disease (AD) and functional recovery after spinal cord injury (SCI). The UPS consists of many factors that include E3 ubiquitin ligases, ubiquitin hydrolases, ubiquitin and ubiquitin-like molecules, and the proteasome itself. An extensive body of work links UPS dysfunction with AD pathogenesis and progression. More recently, the UPS has been shown to have vital roles in recovery of function after SCI. The ubiquitin hydrolase (Uch-L1) has been proposed to increase cellular levels of mono-ubiquitin and hence to increase rates of protein turnover by the UPS. A low Uch-L1 level has been linked with Aβ accumulation in AD and reduced neuroregeneration after SCI. One likely mechanism for these beneficial effects of Uch-L1 is reduced turnover of the PKA regulatory subunit and consequently, reduced signaling via CREB. The neuron-specific F-box protein Fbx2 ubiquitinates β-secretase thus targeting it for proteasomal degradation and reducing generation of Aβ. Both Uch-L1 and Fbx2 improve synaptic plasticity and cognitive function in mouse AD models. The role of Fbx2 after SCI has not been examined, but abolishing ß-secretase reduces neuronal recovery after SCI, associated with reduced myelination. UBB+1, which arises through a frame-shift mutation in the ubiquitin gene that adds 19 amino acids to the C-terminus of ubiquitin, inhibits proteasomal function and is associated with increased neurofibrillary tangles in patients with AD, Pick’s disease and Down’s syndrome. These advances in understanding of the roles of the UPS in AD and SCI raise new questions but, also, identify attractive and exciting targets for potential, future therapeutic interventions.
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Affiliation(s)
- Bing Gong
- Department of Medicine, Mount Sinai School of MedicineNew York, NY, USA; Medicine, James J. Peters Veteran Affairs Medical CenterBronx, NY, USA
| | - Miroslav Radulovic
- Department of Medicine, Mount Sinai School of MedicineNew York, NY, USA; Medicine, James J. Peters Veteran Affairs Medical CenterBronx, NY, USA; National Center of Excellence for the Medical Consequences of Spinal Cord Injury (SCI)Bronx, NY, USA
| | - Maria E Figueiredo-Pereira
- Department of Biological Sciences, Hunter College, and the Graduate School and University Center, The City University of New York New York, NY, USA
| | - Christopher Cardozo
- Department of Medicine, Mount Sinai School of MedicineNew York, NY, USA; Medicine, James J. Peters Veteran Affairs Medical CenterBronx, NY, USA; National Center of Excellence for the Medical Consequences of Spinal Cord Injury (SCI)Bronx, NY, USA
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Deng QS, Dong XY, Wu H, Wang W, Wang ZT, Zhu JW, Liu CF, Jia WQ, Zhang Y, Schachner M, Ma QH, Xu RX. Disrupted-in-Schizophrenia-1 Attenuates Amyloid-β Generation and Cognitive Deficits in APP/PS1 Transgenic Mice by Reduction of β-Site APP-Cleaving Enzyme 1 Levels. Neuropsychopharmacology 2016; 41:440-53. [PMID: 26062786 PMCID: PMC5130120 DOI: 10.1038/npp.2015.164] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 04/27/2015] [Accepted: 05/05/2015] [Indexed: 02/05/2023]
Abstract
Disrupted-in-Schizophrenia-1 (DISC1) is a genetic risk factor for a wide range of major mental disorders, including schizophrenia, major depression, and bipolar disorders. Recent reports suggest a potential role of DISC1 in the pathogenesis of Alzheimer's disease (AD), by referring to an interaction between DISC1 and amyloid precursor protein (APP), and to an association of a single-nucleotide polymorphism in a DISC1 intron and late onset of AD. However, the function of DISC1 in AD remains unknown. In this study, decreased levels of DISC1 were observed in the cortex and hippocampus of 8-month-old APP/PS1 transgenic mice, an animal model of AD. Overexpression of DISC1 reduced, whereas knockdown of DISC1 increased protein levels, but not mRNA levels of β-site APP-Cleaving Enzyme 1 (BACE1), a key enzyme in amyloid-β (Aβ) generation. Reduction of BACE1 protein levels by overexpression of DISC1 was accompanied by an accelerating decline rate of BACE1, and was blocked by the lysosomal inhibitor chloroquine, rather than proteasome inhibitor MG-132. Moreover, overexpression of DISC1 in the hippocampus with an adeno-associated virus reduced the levels of BACE1, soluble Aβ40/42, amyloid plaque density, and rescued cognitive deficits of APP/PS1 transgenic mice. These results indicate that DISC1 attenuates Aβ generation and cognitive deficits of APP/PS1 transgenic mice through promoting lysosomal degradation of BACE1. Our findings provide new insights into the role of DISC1 in AD pathogenesis and link a potential function of DISC1 to the psychiatric symptoms of AD.
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Affiliation(s)
- Qing-Shan Deng
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
| | - Xing-Yu Dong
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
| | - Hao Wu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
| | - Wang Wang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
| | - Zhao-Tao Wang
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
| | - Jian-Wei Zhu
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
| | - Chun-Feng Liu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
| | - Wei-Qiang Jia
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
| | - Yan Zhang
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
| | - Melitta Schachner
- Center for Neuroscience, Shantou University Medical College, Shantou, China
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
| | - Quan-Hong Ma
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute, of Neuroscience, Soochow University, Blk402, Renai Road 199, Suzhou, Jiangsu 215021, China, Tel: +86 18015504376, Fax: +86 512 65880829 E-mail:
| | - Ru-Xiang Xu
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing 100070, China, Tel: +8613391788118, Fax: +86 10 64057752, E-mail:
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He W, Hu J, Xia Y, Yan R. β-site amyloid precursor protein cleaving enzyme 1(BACE1) regulates Notch signaling by controlling the cleavage of Jagged 1 (Jag1) and Jagged 2 (Jag2) proteins. J Biol Chem 2015; 289:20630-7. [PMID: 24907271 DOI: 10.1074/jbc.m114.579862] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
BACE1 is a type I transmembrane aspartyl protease that cleaves amyloid precursor protein at the β-secretase site to initiate the release of β-amyloid peptide. As a secretase, BACE1 also cleaves additional membrane-bound molecules by exerting various cellular functions. In this study, we showed that BACE1 can effectively shed the membrane-anchored signaling molecule Jagged 1 (Jag1).Wealso mapped the cleavage sites of Jag1 by ADAM10 and ADAM17. Although Jag1 shares a high degree of homology with Jag2 in the ectodomain region, BACE1 fails to cleave Jag2 effectively, indicating a selective cleavage of Jag1. Abolished cleavage of Jag1 in BACE1-null mice leads to enhanced astrogenesis and, concomitantly, reduced neurogenesis. This characterization provides biochemical evidence that the Jag1-Notch pathway is under the control of BACE1 activity
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Yan XX, Ma C, Gai WP, Cai H, Luo XG. Can BACE1 inhibition mitigate early axonal pathology in neurological diseases? J Alzheimers Dis 2014; 38:705-18. [PMID: 24081378 DOI: 10.3233/jad-131400] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
β-Secretase-1 (BACE1) is the rate-limiting enzyme for the genesis of amyloid-β (Aβ) peptides, the main constituents of the amyloid plaques in the brains of Alzheimer's disease (AD) patients. BACE1 is being evaluated as an anti-Aβ target for AD therapy. Recent studies indicate that BACE1 elevation is associated with axonal and presynaptic pathology during plaque development. Evidence also points to a biological role for BACE1 in axonal outgrowth and synapse formation during development. Axonal, including presynaptic, pathology exists in AD as well as many other neurological disorders such as Parkinson's disease, epilepsy, stroke, and trauma. In this review, we discuss pharmaceutical BACE1 inhibition as a therapeutic option for axonal pathogenesis, in addition to amyloid pathology. We first introduce the amyloidogenic processing of amyloid-β protein precursor and describe the normal expression pattern of the amyloidogenic proteins in the brain, with an emphasis on BACE1. We then address BACE1 elevation relative to amyloid plaque development, followed by updating recent understanding of a neurotrophic role of BACE1 in axon and synapse development. We further elaborate the occurrence of axonal pathology in some other neurological conditions. Finally, we propose pharmacological inhibition of excessive BACE1 activity as an option to mitigate early axonal pathology occurring in AD and other neurological disorders.
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Affiliation(s)
- Xiao-Xin Yan
- Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan, China
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40
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Abstract
Alzheimer's disease (AD) is a neurodegenerative disease of the central nervous system that causes dementia in a large percentage of the aged population and for which there are only symptomatic treatments. Disease-modifying therapies that are currently being pursued are based on the amyloid cascade theory. This states that accumulation of amyloid β (Aβ) in the brain triggers a cascade of cellular events leading to neurodegeneration. Aβ, which is the major constituent of amyloid plaques, is a peptidic fragment derived from proteolytic processing of the amyloid precursor protein (APP) by sequential cleavages that involve β-site APP-cleaving enzyme 1 (BACE1) and γ-secretase. Targeting BACE1 is a rational approach as its cleavage of APP is the rate-limiting step in Aβ production and this enzyme is elevated in the brain of patients with AD. Furthermore, knocking out the BACE1 gene in mice showed little apparent consequences. Ten years of intensive research has led to the design of efficacious BACE1 inhibitors with favorable pharmacological properties. Several drug candidates have shown promising results in animal models, as they reduce amyloid plaque pathology in the brain and rescue cognitive deficits. Phase I clinical trials indicate that these drugs are well tolerated, and the results from further trials in AD patients are now awaited eagerly. Yet, recent novel information on BACE1 biology, and the discovery that BACE1 cleaves a selection of substrates involved in myelination, retinal homeostasis, brain circuitry, and synaptic function, alert us to potential side effects of BACE1 inhibitors that will require further evaluation to provide a safe therapy for AD.
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41
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Henriques AG, Oliveira JM, Gomes B, Ruivo R, da Cruz e Silva EF, da Cruz e Silva OAB. Complexing Aβ prevents the cellular anomalies induced by the Peptide alone. J Mol Neurosci 2014; 53:661-8. [PMID: 24599756 PMCID: PMC4112052 DOI: 10.1007/s12031-014-0233-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 01/10/2014] [Indexed: 12/01/2022]
Abstract
Retention of intracellular secreted APP (isAPP) can be provoked by the neurotoxic peptide Aβ. The latter decreases in the cerebrospinal fluid of Alzheimer’s disease (AD) patients, as a consequence of its cerebral accumulation and deposition into senile plaques. Of similar relevance, secreted APP (sAPP) levels can be associated with AD. The studies here presented, reinforce the link between sAPP and Aβ and address putative therapeutic strategies. Laminin and gelsolin are potential candidates; both prevent Aβ fibril formation by complexing with Aβ, thus attenuating its neurotoxicity. We show that preincubation of Aβ with laminin and gelsolin has the effect of rendering it less potent to isAPP accumulation in cortical neurons. This appears to be related to a decrease in F-actin polymerization, whereas Aβ alone induces the polymerization. Further, Aβ decreases gelsolin levels, and the latter is involved in Aβ removal. Our data indicates that Aβ-laminin and Aβ-gelsolin complexes are less neurotoxic and also less potent than fibrillar Aβ at inducing isAPP retention. These results validate the potential of these proteins as therapeutic strategies that prevent the Aβ-induced effects. In hence, given that Aβ decreases the levels of proteins involved in its own clearance, this may contribute to the mechanisms underlying AD pathology.
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Affiliation(s)
- A. G. Henriques
- Laboratório de Neurociências, Centro de Biologia Celular, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - J. M. Oliveira
- Laboratório de Neurociências, Centro de Biologia Celular, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - B. Gomes
- Laboratório de Neurociências, Centro de Biologia Celular, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - R. Ruivo
- Laboratório de Neurociências, Centro de Biologia Celular, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - E. F. da Cruz e Silva
- Laboratório de Neurociências, Centro de Biologia Celular, SACS, Universidade de Aveiro, Aveiro, Portugal
| | - O. A. B. da Cruz e Silva
- Laboratório de Neurociências, Centro de Biologia Celular, SACS, Universidade de Aveiro, Aveiro, Portugal
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Evin G, Barakat A. Critical analysis of the use of β-site amyloid precursor protein-cleaving enzyme 1 inhibitors in the treatment of Alzheimer's disease. Degener Neurol Neuromuscul Dis 2014; 4:1-19. [PMID: 32669897 PMCID: PMC7337240 DOI: 10.2147/dnnd.s41056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/06/2014] [Indexed: 01/18/2023] Open
Abstract
Alzheimer’s disease (AD) is the major cause of dementia in the elderly and an unmet clinical challenge. A variety of therapies that are currently under development are directed to the amyloid cascade. Indeed, the accumulation and toxicity of amyloid-β (Aβ) is believed to play a central role in the etiology of the disease, and thus rational interventions are aimed at reducing the levels of Aβ in the brain. Targeting β-site amyloid precursor protein-cleaving enzyme (BACE)-1 represents an attractive strategy, as this enzyme catalyzes the initial and rate-limiting step in Aβ production. Observation of increased levels of BACE1 and enzymatic activity in the brain, cerebrospinal fluid, and platelets of patients with AD and mild cognitive impairment supports the potential benefits of BACE1 inhibition. Numerous potent inhibitors have been generated, and many of these have been proved to lower Aβ levels in the brain of animal models. Over 10 years of intensive research on BACE1 inhibitors has now culminated in advancing half a dozen of these drugs into human trials, yet translating the in vitro and cellular efficacy of BACE1 inhibitors into preclinical and clinical trials represents a challenge. This review addresses the promises and also the potential problems associated with BACE1 inhibitors for AD therapy, as the complex biological function of BACE1 in the brain is becoming unraveled.
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Affiliation(s)
- Genevieve Evin
- Oxidation Biology Laboratory, Mental Health Research Institute, Florey Institute of Neuroscience and Mental Health, University of Melbourne.,Department of Pathology, University of Melbourne, Parkville, VIC, Australia
| | - Adel Barakat
- Department of Pathology, University of Melbourne, Parkville, VIC, Australia
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Shahani N, Pryor W, Swarnkar S, Kholodilov N, Thinakaran G, Burke RE, Subramaniam S. Rheb GTPase regulates β-secretase levels and amyloid β generation. J Biol Chem 2013; 289:5799-808. [PMID: 24368770 DOI: 10.1074/jbc.m113.532713] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The β-site amyloid precursor protein (APP)-cleaving enzyme 1 (β-secretase, BACE1) initiates amyloidogenic processing of APP to generate amyloid β (Aβ), which is a hallmark of Alzheimer disease (AD) pathology. Cerebral levels of BACE1 are elevated in individuals with AD, but the molecular mechanisms are not completely understood. We demonstrate that Rheb GTPase (Ras homolog enriched in brain), which induces mammalian target of rapamycin (mTOR) activity, is a physiological regulator of BACE1 stability and activity. Rheb overexpression depletes BACE1 protein levels and reduces Aβ generation, whereas the RNAi knockdown of endogenous Rheb promotes BACE1 accumulation, and this effect by Rheb is independent of its mTOR signaling. Moreover, GTP-bound Rheb interacts with BACE1 and degrades it through proteasomal and lysosomal pathways. Finally, we demonstrate that Rheb levels are down-regulated in the AD brain, which is consistent with an increased BACE1 expression. Altogether, our study defines Rheb as a novel physiological regulator of BACE1 levels and Aβ generation, and the Rheb-BACE1 circuitry may have a role in brain biology and disease.
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Affiliation(s)
- Neelam Shahani
- From the Department of Neuroscience, The Scripps Research Institute, Florida, Jupiter, Florida 33458
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44
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Munter LM, Sieg H, Bethge T, Liebsch F, Bierkandt FS, Schleeger M, Bittner HJ, Heberle J, Jakubowski N, Hildebrand PW, Multhaup G. Model Peptides Uncover the Role of the β-Secretase Transmembrane Sequence in Metal Ion Mediated Oligomerization. J Am Chem Soc 2013; 135:19354-61. [DOI: 10.1021/ja410812r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lisa M. Munter
- Department of Pharmacology
and Therapeutics, McGill University, 3655 Promenade Sir William Osler, H3G 1Y6 Montreal, Canada
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Holger Sieg
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Tobias Bethge
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
| | - Filip Liebsch
- Department of Pharmacology
and Therapeutics, McGill University, 3655 Promenade Sir William Osler, H3G 1Y6 Montreal, Canada
| | - Frank S. Bierkandt
- Division 1.1 “Inorganic
Trace Analysis”, BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Straße 11, 12489 Berlin, Germany
| | - Michael Schleeger
- Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Heiko J. Bittner
- Institut für Medizinische
Physik und Biophysik, ProteInformatics Group, Charité, Charitéplatz
1, 10117 Berlin, Germany
| | - Joachim Heberle
- Experimental Molecular Biophysics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Norbert Jakubowski
- Division 1.1 “Inorganic
Trace Analysis”, BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Straße 11, 12489 Berlin, Germany
| | - Peter W. Hildebrand
- Institut für Medizinische
Physik und Biophysik, ProteInformatics Group, Charité, Charitéplatz
1, 10117 Berlin, Germany
| | - Gerd Multhaup
- Department of Pharmacology
and Therapeutics, McGill University, 3655 Promenade Sir William Osler, H3G 1Y6 Montreal, Canada
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
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Hamada Y, Suzuki K, Nakanishi T, Sarma D, Ohta H, Yamaguchi R, Yamasaki M, Hidaka K, Ishiura S, Kiso Y. Structure-activity relationship study of BACE1 inhibitors possessing a chelidonic or 2,6-pyridinedicarboxylic scaffold at the P(2) position. Bioorg Med Chem Lett 2013; 24:618-23. [PMID: 24360554 DOI: 10.1016/j.bmcl.2013.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 11/27/2013] [Accepted: 12/02/2013] [Indexed: 11/16/2022]
Abstract
We have previously reported potent substrate-based pentapeptidic BACE1 inhibitors possessing a hydroxymethylcarbonyl isostere as a substrate transition-state mimic. While these inhibitors exhibited potent activities in enzymatic and cellular assays (KMI-429 in particular inhibited Aβ production in vivo), these inhibitors contained some natural amino acids that seemed to be required to improve enzymatic stability in vivo and permeability across the blood-brain barrier, so as to be practical drug. Recently, we synthesized non-peptidic and small-sized BACE1 inhibitors possessing a heterocyclic scaffold at the P2 position. Herein we report the SAR study of BACE1 inhibitors possessing this heterocyclic scaffold, a chelidonic or 2,6-pyridinedicarboxylic moiety.
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Affiliation(s)
- Yoshio Hamada
- Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Minatojima, Chuo-ku, Kobe 650-8586, Japan; Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan.
| | - Kenji Suzuki
- Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | - Tomoya Nakanishi
- Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | - Diganta Sarma
- Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | - Hiroko Ohta
- Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | - Ryoji Yamaguchi
- Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | - Moe Yamasaki
- Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | - Koushi Hidaka
- Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan
| | - Shoichi Ishiura
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Yoshiaki Kiso
- Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Minatojima, Chuo-ku, Kobe 650-8586, Japan; Center for Frontier Research in Medicinal Science, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8412, Japan; Laboratory of Peptide Science, Nagahama Institute of Bio-Science and Technology, Tamura-cho, Nagahama 526-0829, Japan
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Trafficking in neurons: Searching for new targets for Alzheimer's disease future therapies. Eur J Pharmacol 2013; 719:84-106. [DOI: 10.1016/j.ejphar.2013.07.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/11/2013] [Indexed: 11/22/2022]
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47
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Zhang X, Song W. The role of APP and BACE1 trafficking in APP processing and amyloid-β generation. ALZHEIMERS RESEARCH & THERAPY 2013; 5:46. [PMID: 24103387 PMCID: PMC3978418 DOI: 10.1186/alzrt211] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neuritic plaques in the brain are a major neuropathological hallmark of Alzheimer’s disease. They are formed by the deposition and aggregation of extracellular amyloid-β protein (Aβ). Aβ is derived from the sequential cleavage of amyloid-β precursor protein (APP) by β-secretase and γ-secretase. β-Site APP cleaving enzyme 1 (BACE1) functions as the primary, if not sole, β-secretase in vivo and is essential for Aβ production. Regulation of APP processing is a major focus of research into AD pathogenesis. The trafficking systems of APP and its cleavage enzymes are complex. Transporting APP and secretases into the same subcellular organelles facilitates their interaction and favors APP processing. The role of APP and BACE1 trafficking in the amyloidgenic pathway and the underlying mechanisms for Aβ production are discussed in this review. In addition, the distinct mechanisms of amino- and carboxy-terminal Aβ generation are reviewed.
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Affiliation(s)
- Xiaojie Zhang
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, 2255 Wesbrook Mall, Vancouver BC V6T 1Z3, Canada
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, 2255 Wesbrook Mall, Vancouver BC V6T 1Z3, Canada
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Li X, Hong L, Coughlan K, Wang L, Cao L, Tang J. Structure-activity relationship of memapsin 2: implications on physiological functions and Alzheimer's disease. Acta Biochim Biophys Sin (Shanghai) 2013; 45:613-21. [PMID: 23676825 DOI: 10.1093/abbs/gmt050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Memapsin 2 (BACE1, β-secretase), a membrane aspartic protease, functions in the cleavage of the type I transmembrane protein, β-amyloid precursor protein (APP), leading to the production of amyloid β (Aβ) in the brain. Since Aβ is closely associated with the pathogenesis of Alzheimer's disease, understanding the biological function, particularly the catalytic activities of memapsin 2, would assist in a better understanding of the disease and the development of its inhibitors. The transmembrane and cytosolic domains of memapsin 2 function in cellular transport and localization, which are important regulatory mechanisms for its activity. The catalytic ectodomain contains a long substrate cleft that is responsible for substrate recognition, specificity, and peptide bond hydrolysis. The substrate cleft accommodates 11 residues of the substrate in separate binding subsites. Besides APP, a number of membrane proteins have been reported to be substrates of memapsin 2. The elucidation for the specificity of these subsites and the amino acid sequences surrounding the memapsin 2 cleavage site in these proteins has led to the establishment of a predictive model that can quantitatively estimate the efficiency of cleavage for any potential substrates. Such tools may be employed for future studies of memapsin 2 about its biological function. Herein, we review the current knowledge on the structure-function relationship of memapsin 2 and its relationship in the biological function.
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Affiliation(s)
- Xiaoman Li
- Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang 110001, China
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Charfi C, Levros LC, Edouard E, Rassart E. Characterization and identification of PARM-1 as a new potential oncogene. Mol Cancer 2013; 12:84. [PMID: 23902727 PMCID: PMC3750824 DOI: 10.1186/1476-4598-12-84] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 07/25/2013] [Indexed: 11/21/2022] Open
Abstract
Background The Graffi murine retrovirus is a powerful tool to find leukemia associated oncogenes. Using DNA microarrays, we recently identified several genes specifically deregulated in T- and B-leukemias induced by this virus. Results In the present study, probsets associated with T-CD8+ leukemias were analyzed and we validated the expression profile of the Parm-1 gene. PARM-1 is a member of the mucin family. We showed that human PARM-1 is an intact secreted protein accumulating predominantly, such as murine PARM-1, at the Golgi and in the early and late endosomes. PARM-1 colocalization with α-tubulin suggests that its trafficking within the cell involves the microtubule cytoskeleton. Also, the protein co-localizes with caveolin-1 which probably mediates its internalization. Transient transfection of both mouse and human Parm-1 cDNAs conferred anchorage- and serum-independent growth and enhanced cell proliferation. Moreover, deletion mutants of human PARM-1 without either extracellular or cytoplasmic portions seem to retain the ability to induce anchorage-independent growth of NIH/3T3 cells. In addition, PARM-1 increases ERK1/2, but more importantly AKT and STAT3 phosphorylation. Conclusions Our results strongly suggest the oncogenic potential of PARM-1.
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Affiliation(s)
- Cyndia Charfi
- Laboratoire de Biologie Moléculaire, Département des Sciences Biologiques, Centre BioMed, Université du Québec à Montréal, Case Postale 8888, Succursale Centre-ville, Montréal, QC H3C-3P8, Canada
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50
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Hu X, He W, Luo X, Tsubota KE, Yan R. BACE1 regulates hippocampal astrogenesis via the Jagged1-Notch pathway. Cell Rep 2013; 4:40-9. [PMID: 23831026 DOI: 10.1016/j.celrep.2013.06.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 05/24/2013] [Accepted: 06/04/2013] [Indexed: 01/18/2023] Open
Abstract
BACE1 is the sole secretase for generating β-amyloid (Aβ) in vivo and is being actively pursued as a drug target for the treatment of Alzheimer's disease. Transmembrane BACE1 exerts its biological activity by cleaving its membrane-bound cellular substrates. Here, we reveal that BACE1 directly regulates the level of membrane-anchored full-length Jagged1 (Jag1), a signaling molecule important for the control of neurogenesis and astrogenesis, via interaction with its cognate Notch receptor. We show that shedding of Jag1 is reduced in BACE1 null mice and upregulated Jag1 enhances Notch signaling via cell-cell juxtacrine interactions. Additional biochemical assays confirmed that overexpression of BACE1 enhanced cleavage of Jag1. Consequently, BACE1 null mice exhibit a significant increase in astrogenesis with a corresponding decrease in neurogenesis in their hippocampi during early development. Hence, BACE1 appears to function as a signaling protease that controls the balance of neurogenesis and astrogenesis via the Jag1-Notch pathway.
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Affiliation(s)
- Xiangyou Hu
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
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