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Haut F, Argyrousi EK, Arancio O. Re-Arranging the Puzzle between the Amyloid-Beta and Tau Pathology: An APP-Centric Approach. Int J Mol Sci 2023; 25:259. [PMID: 38203429 PMCID: PMC10779219 DOI: 10.3390/ijms25010259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/04/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024] Open
Abstract
After several years of research in the field of Alzheimer's disease (AD), it is still unclear how amyloid-beta (Aβ) and Tau, two key hallmarks of the disease, mediate the neuropathogenic events that lead to AD. Current data challenge the "Amyloid Cascade Hypothesis" that has prevailed in the field of AD, stating that Aβ precedes and triggers Tau pathology that will eventually become the toxic entity in the progression of the disease. This perspective also led the field of therapeutic approaches towards the development of strategies that target Aβ or Tau. In the present review, we discuss recent literature regarding the neurotoxic role of both Aβ and Tau in AD, as well as their physiological function in the healthy brain. Consequently, we present studies suggesting that Aβ and Tau act independently of each other in mediating neurotoxicity in AD, thereafter, re-evaluating the "Amyloid Cascade Hypothesis" that places Tau pathology downstream of Aβ. More recent studies have confirmed that both Aβ and Tau could propagate the disease and induce synaptic and memory impairments via the amyloid precursor protein (APP). This finding is not only interesting from a mechanistic point of view since it provides better insights into the AD pathogenesis but also from a therapeutic point of view since it renders APP a common downstream effector for both Aβ and Tau. Subsequently, therapeutic strategies that act on APP might provide a more viable and physiologically relevant approach for targeting AD.
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Affiliation(s)
- Florence Haut
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, 630 West 168th Street, P&S, New York, NY 10032, USA; (F.H.); (E.K.A.)
| | - Elentina K. Argyrousi
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, 630 West 168th Street, P&S, New York, NY 10032, USA; (F.H.); (E.K.A.)
| | - Ottavio Arancio
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, 630 West 168th Street, P&S, New York, NY 10032, USA; (F.H.); (E.K.A.)
- Department of Medicine, Columbia University, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
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2
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Fulop T, Ramassamy C, Lévesque S, Frost EH, Laurent B, Lacombe G, Khalil A, Larbi A, Hirokawa K, Desroches M, Rodrigues S, Bourgade K, Cohen AA, Witkowski JM. Viruses - a major cause of amyloid deposition in the brain. Expert Rev Neurother 2023; 23:775-790. [PMID: 37551672 DOI: 10.1080/14737175.2023.2244162] [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: 04/01/2023] [Accepted: 07/31/2023] [Indexed: 08/09/2023]
Abstract
INTRODUCTION Clinically, Alzheimer's disease (AD) is a syndrome with a spectrum of various cognitive disorders. There is a complete dissociation between the pathology and the clinical presentation. Therefore, we need a disruptive new approach to be able to prevent and treat AD. AREAS COVERED In this review, the authors extensively discuss the evidence why the amyloid beta is not the pathological cause of AD which makes therefore the amyloid hypothesis not sustainable anymore. They review the experimental evidence underlying the role of microbes, especially that of viruses, as a trigger/cause for the production of amyloid beta leading to the establishment of a chronic neuroinflammation as the mediator manifesting decades later by AD as a clinical spectrum. In this context, the emergence and consequences of the infection/antimicrobial protection hypothesis are described. The epidemiological and clinical data supporting this hypothesis are also analyzed. EXPERT OPINION For decades, we have known that viruses are involved in the pathogenesis of AD. This discovery was ignored and discarded for a long time. Now we should accept this fact, which is not a hypothesis anymore, and stimulate the research community to come up with new ideas, new treatments, and new concepts.
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Affiliation(s)
- Tamas Fulop
- Research Center on Aging, Centre Intégré Universitaire de Santé Et Services Sociaux de l'Estrie-Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
- Department of Medicine, Division of Geriatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | | | - Simon Lévesque
- CIUSSS de l'Estrie - CHUS, Sherbrooke, QC, Canada
- Département de Microbiologie Et Infectiologie, Faculté de Médecine Et des Sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Eric H Frost
- Département de Microbiologie Et Infectiologie, Faculté de Médecine Et des Sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Benoit Laurent
- Research Center on Aging, Centre Intégré Universitaire de Santé Et Services Sociaux de l'Estrie-Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Guy Lacombe
- Research Center on Aging, Centre Intégré Universitaire de Santé Et Services Sociaux de l'Estrie-Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
- Department of Medicine, Division of Geriatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Abedelouahed Khalil
- Research Center on Aging, Centre Intégré Universitaire de Santé Et Services Sociaux de l'Estrie-Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
- Department of Medicine, Division of Geriatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Anis Larbi
- Department of Medicine, Division of Geriatrics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Katsuiku Hirokawa
- Department of Pathology, Institute of Health and Life Science, Tokyo Medical Dental University, Tokyo and Nito-Memory Nakanosogo Hospital, Tokyo, Japan
| | - Mathieu Desroches
- MathNeuro Team, Inria Sophia Antipolis Méditerranée, Biot, France
- Université Côte d'Azur, Nice, France
| | - Serafim Rodrigues
- Ikerbasque, BCAM, the Basque Foundation for Science and BCAM - The Basque Center for Applied Mathematics, Bilbao, Spain
| | - Karine Bourgade
- Research Center on Aging, Centre Intégré Universitaire de Santé Et Services Sociaux de l'Estrie-Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada
| | - Alan A Cohen
- Department of Environmental Health Sciences, Butler Columbia Aging Center, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Jacek M Witkowski
- Department of Pathophysiology, Medical University of Gdansk, Gdansk, Poland
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PS1 Affects the Pathology of Alzheimer's Disease by Regulating BACE1 Distribution in the ER and BACE1 Maturation in the Golgi Apparatus. Int J Mol Sci 2022; 23:ijms232416151. [PMID: 36555791 PMCID: PMC9782474 DOI: 10.3390/ijms232416151] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 11/28/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022] Open
Abstract
Neuritic plaques are one of the major pathological hallmarks of Alzheimer's disease. They are formed by the aggregation of extracellular amyloid-β protein (Aβ), which is derived from the sequential cleavage of amyloid-β precursor protein (APP) by β- and γ-secretase. BACE1 is the main β-secretase in the pathogenic process of Alzheimer's disease, which is believed to be a rate-limiting step of Aβ production. Presenilin 1 (PS1) is the active center of the γ-secretase that participates in the APP hydrolysis process. Mutations in the PS1 gene (PSEN1) are the most common cause of early onset familial Alzheimer's disease (FAD). The PSEN1 mutations can alter the activity of γ-secretase on the cleavage of APP. Previous studies have shown that PSEN1 mutations increase the expression and activity of BACE1 and that BACE1 expression and activity are elevated in the brains of PSEN1 mutant knock-in mice, compared with wild-type mice, as well as in the cerebral cortex of FAD patients carrying PSEN1 mutations, compared with sporadic AD patients and controls. Here, we used a Psen1 knockout cell line and a PS1 inhibitor to show that PS1 affects the expression of BACE1 in vitro. Furthermore, we used sucrose gradient fractionation combined with western blotting to analyze the distribution of BACE1, combined with a time-lapse technique to show that PS1 upregulates the distribution and trafficking of BACE1 in the endoplasmic reticulum, Golgi, and endosomes. More importantly, we found that the PSEN1 mutant S170F increases the distribution of BACE1 in the endoplasmic reticulum and changes the ratio of mature BACE1 in the trans-Golgi network. The effect of PSEN1 mutations on BACE1 may contribute to determining the phenotype of early onset FAD.
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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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5
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Alexander C, Li T, Hattori Y, Chiu D, Frost GR, Jonas L, Liu C, Anderson CJ, Wong E, Park L, Iadecola C, Li YM. Hypoxia Inducible Factor-1α binds and activates γ-secretase for Aβ production under hypoxia and cerebral hypoperfusion. Mol Psychiatry 2022; 27:4264-4273. [PMID: 35764706 PMCID: PMC9722522 DOI: 10.1038/s41380-022-01676-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 06/09/2022] [Accepted: 06/15/2022] [Indexed: 02/07/2023]
Abstract
Hypoxic-ischemic injury has been linked with increased risk for developing Alzheimer's disease (AD). The underlying mechanism of this association is poorly understood. Here, we report distinct roles for hypoxia-inducible factor-1α (Hif-1α) in the regulation of BACE1 and γ-secretase activity, two proteases involved in the production of amyloid-beta (Aβ). We have demonstrated that Hif-1α upregulates both BACE1 and γ-secretase activity for Aβ production in brain hypoxia-induced either by cerebral hypoperfusion or breathing 10% O2. Hif-1α binds to γ-secretase, which elevates the amount of active γ-secretase complex without affecting the level of individual subunits in hypoxic-ischemic mouse brains. Additionally, the expression of full length Hif-1α increases BACE1 and γ-secretase activity in primary neuronal culture, whereas a transcriptionally incompetent Hif-1α variant only activates γ-secretase. These findings indicate that Hif-1α transcriptionally upregulates BACE1 and nontranscriptionally activates γ-secretase for Aβ production in hypoxic-ischemic conditions. Consequently, Hif-1α-mediated Aβ production may be an adaptive response to hypoxic-ischemic injury, subsequently leading to increased risk for AD. Preventing the interaction of Hif-1α with γ-secretase may therefore be a promising therapeutic strategy for AD treatment.
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Affiliation(s)
- Courtney Alexander
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Programs of Neurosciences and Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
| | - Thomas Li
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Programs of Neurosciences and Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
| | - Yorito Hattori
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Danica Chiu
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Programs of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
| | - Georgia R Frost
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Programs of Neurosciences and Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
| | - Lauren Jonas
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Programs of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
| | - Chenge Liu
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Programs of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
| | - Corey J Anderson
- Programs of Neurosciences and Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Eitan Wong
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Laibaik Park
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Costantino Iadecola
- Programs of Neurosciences and Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Yue-Ming Li
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Programs of Neurosciences and Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA.
- Programs of Pharmacology, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA.
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6
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Raha S, Ghosh A, Dutta D, Patel DR, Pahan K. Activation of PPARα enhances astroglial uptake and degradation of β-amyloid. Sci Signal 2021; 14:eabg4747. [PMID: 34699252 DOI: 10.1126/scisignal.abg4747] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Sumita Raha
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Arunava Ghosh
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Debashis Dutta
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Dhruv R Patel
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Kalipada Pahan
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA.,Division of Research and Development, Jesse Brown Veterans Affairs Medical Center, Chicago, IL 60612, USA
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7
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Armbrust F, Bickenbach K, Marengo L, Pietrzik C, Becker-Pauly C. The Swedish dilemma - the almost exclusive use of APPswe-based mouse models impedes adequate evaluation of alternative β-secretases. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1869:119164. [PMID: 34699873 DOI: 10.1016/j.bbamcr.2021.119164] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/30/2021] [Accepted: 10/11/2021] [Indexed: 02/07/2023]
Abstract
Alzheimer's disease (AD) is the most common form of dementia, however incurable so far. It is widely accepted that aggregated amyloid β (Aβ) peptides play a crucial role for the pathogenesis of AD, as they cause neurotoxicity and deposit as so-called Aβ plaques in AD patient brains. Aβ peptides derive from the amyloid precursor protein (APP) upon consecutive cleavage at the β- and γ-secretase site. Hence, mutations in the APP gene are often associated with autosomal dominant inherited AD. Almost thirty years ago, two mutations at the β-secretase site were observed in two Swedish families (termed Swedish APP (APPswe) mutations), which led to early-onset AD. Consequently, APPswe was established in almost every common AD mouse model, as it contributes to early Aβ plaque formation and cognitive impairments. Analyzing these APPswe-based mouse models, the aspartyl protease BACE1 has been evolving as the prominent β-secretase responsible for Aβ release in AD and as the most important therapeutic target for AD treatment. However, with respect to β-secretase processing, the very rare occurring APPswe variant substantially differs from wild-type APP. BACE1 dominates APPswe processing resulting in the release of Aβ1-x, whereas N-terminally truncated Aβ forms are scarcely generated. However, these N-terminally truncated Aβ species such as Aβ2-x, Aβ3-x and Aβ4-x are elevated in AD patient brains and exhibit an increased potential to aggregate compared to Aβ1-x peptides. Proteases such as meprin β, cathepsin B and ADAMTS4 were identified as alternative β-secretases being capable of generating these N-terminally truncated Aβ species from wild-type APP. However, neither meprin β nor cathepsin B are capable of generating N-terminally truncated Aβ peptides from APPswe. Hence, the role of BACE1 for the Aβ formation during AD might be overrepresented through the excessive use of APPswe mouse models. In this review we critically discuss the consideration of BACE1 as the most promising therapeutic target. Shifting the focus of AD research towards alternative β secretases might unveil promising alternatives to BACE1 inhibitors constantly failing in clinical trials due to ineffectiveness and harmful side effects.
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Affiliation(s)
- Fred Armbrust
- Biochemical Institute, Unit for Degradomics of the Protease Web, University of Kiel, Kiel, Germany
| | - Kira Bickenbach
- Biochemical Institute, Unit for Degradomics of the Protease Web, University of Kiel, Kiel, Germany
| | - Liana Marengo
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Claus Pietrzik
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.
| | - Christoph Becker-Pauly
- Biochemical Institute, Unit for Degradomics of the Protease Web, University of Kiel, Kiel, Germany.
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Shah H, Patel A, Parikh V, Nagani A, Bhimani B, Shah U, Bambharoliya T. The β-Secretase Enzyme BACE1: A Biochemical Enigma for Alzheimer's Disease. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2021; 19:184-194. [PMID: 32452328 DOI: 10.2174/1871527319666200526144141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 04/18/2020] [Accepted: 04/29/2020] [Indexed: 01/08/2023]
Abstract
Beta site amyloid precursor protein cleaving enzyme 1 (BACE1) is a rational target in Alzheimer's Disease (AD) drug development due to its role in amyloidogenic cleavage of Amyloid Precursor Protein (APP) in generating Amyloid β (Aβ). This β-secretase cleaves not only Amyloid Precursor Protein (APP) and its homologues, but also small series of substrates including neuregulin and β subunit of voltage-gated sodium channel that play a very important role in the development and normal function of the brain. Moreover, BACE1 is modulated at the post-translational level by several factors that are associated with both physiological and pathological functions. Since the discovery of BACE1 over a decade ago, medicinal chemistry and pharmacokinetics of BACE1 small molecule inhibitors have proven challenging for the treatment of Alzheimer's disease.
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Affiliation(s)
- Hirak Shah
- Department of Pharmaceutical Chemistry, Parul Institute of Pharmacy, Parul University, Vadodara, Gujarat 391760, India
| | - Ashish Patel
- Ramanbhai Patel College of Pharmacy, Charotar University of Science and Technology, Changa, Gujarat 388421, India
| | - Vruti Parikh
- Department of Pharmaceutical Chemistry, Parul Institute of Pharmacy, Parul University, Vadodara, Gujarat 391760, India
| | - Afzal Nagani
- Department of Pharmaceutical Chemistry, Parul Institute of Pharmacy, Parul University, Vadodara, Gujarat 391760, India
| | - Bhargav Bhimani
- Piramal Discovery Solution, Pharmaceutical Special Economic Zone, Ahmedabad 382213, India
| | - Umang Shah
- Ramanbhai Patel College of Pharmacy, Charotar University of Science and Technology, Changa, Gujarat 388421, India
| | - Tushar Bambharoliya
- Pharmaceutical Polymer Technology, North Carolina State University, North Carolina, NC, United States
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9
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Delta- and beta- secretases crosstalk amplifies the amyloidogenic pathway in Alzheimer's disease. Prog Neurobiol 2021; 204:102113. [PMID: 34166772 DOI: 10.1016/j.pneurobio.2021.102113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 05/17/2021] [Accepted: 06/18/2021] [Indexed: 11/20/2022]
Abstract
Asparagine endopeptidase (AEP), a newly identified delta-secretase, simultaneously cleaves both APP and Tau, promoting Alzheimer's disease (AD) pathologies. However, its pathological role in AD remains incompletely understood. Here we show that delta-secretase cleaves BACE1, a rate-limiting protease in amyloid-β (Aβ) generation, escalating its enzymatic activity and enhancing senile plaques deposit in AD. Delta-secretase binds BACE1 and cuts it at N294 residue in an age-dependent manner and elevates its protease activity. The cleaved N-terminal motif is active even under neutral pH and associates with senile plaques in human AD brains. Subcellular fractionation reveals that delta-secretase and BACE1 reside in the endo-lysosomes. Interestingly, truncated BACE1 enzymatic domain (1-294) augments delta-secretase enzymatic activity and accelerates Aβ production, facilitating AD pathologies and cognitive impairments in APP/PS1 AD mouse model. Uncleavable BACE1 (N294A) inhibits delta-secretase activity and Aβ production and decreases AD pathologies in 5XFAD mice, ameliorating cognitive dysfunctions. Hence, delta- and beta- secretases' crosstalk aggravates each other's roles in AD pathogenesis.
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10
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Ugbaja SC, Lawal M, Kumalo H. An Overview of β-Amyloid Cleaving Enzyme 1 (Bace1) in Alzheimer's Disease Therapy Elucidating its Exosite-Binding Antibody and Allosteric Inhibitor. Curr Med Chem 2021; 29:114-135. [PMID: 34102967 DOI: 10.2174/0929867328666210608145357] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/18/2021] [Accepted: 04/19/2021] [Indexed: 11/22/2022]
Abstract
Over decades of its identification, numerous past and ongoing researches have focused on the therapeutic roles of β-amyloid cleaving enzyme 1 (BACE1) as a target in treating Alzheimer's disease (AD). Although the initial BACE1 inhibitors at phase-3 clinical trials tremendously reduced β-amyloid-associated plaques in patients with AD, the researchers eventually discontinued the tests due to the lack of potency. This discontinuation has resulted in limited drug development and discovery targeted at BACE1, despite the high demand for dementia and AD therapies. It is, therefore, imperative to describe the detailed underlying biological basis of the BACE1 therapeutic option in neurological diseases. Herein, we highlight BACE1 bioactivity, genetic properties, and role in neurodegenerative therapy. We review research contributions to BACE1 exosite-binding antibody and allosteric inhibitor development as AD therapies. The review also covers BACE1 biological function, the disease-associated mechanisms, and the enzyme conditions for amyloid precursor protein sites splitting. Based on the present review, we suggest further studies on anti-BACE1 exosite antibodies and BACE1 allosteric inhibitors. Non-active site inhibition might be the way forward to BACE1 therapy in Alzheimer's neurological disorder.
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Affiliation(s)
- Samuel C Ugbaja
- Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban 4001, South Africa
| | - Monsurat Lawal
- Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban 4001, South Africa
| | - Hezekiel Kumalo
- Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Science, University of KwaZulu-Natal, Durban 4001, South Africa
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11
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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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12
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Cortada E, Serradesanferm R, Brugada R, Verges M. The voltage-gated sodium channel β2 subunit associates with lipid rafts by S-palmitoylation. J Cell Sci 2021; 134:jcs.252189. [PMID: 33602743 DOI: 10.1242/jcs.252189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 02/08/2021] [Indexed: 12/19/2022] Open
Abstract
The voltage-gated sodium channel is critical for cardiomyocyte function. It consists of a protein complex comprising a pore-forming α subunit and associated β subunits. In polarized Madin-Darby canine kidney cells, we show evidence by acyl-biotin exchange that β2 is S-acylated at Cys-182. Interestingly, we found that palmitoylation increases β2 association with detergent-resistant membranes. β2 localizes exclusively to the apical surface. However, depletion of plasma membrane cholesterol, or blocking intracellular cholesterol transport, caused mislocalization of β2, as well as of the non-palmitoylable C182S mutant, to the basolateral domain. Apical β2 did not undergo endocytosis and displayed limited diffusion within the plane of the membrane; such behavior suggests that, at least in part, it is cytoskeleton anchored. Upon acute cholesterol depletion, its mobility was greatly reduced, and a slight reduction was also measured as a result of lack of palmitoylation, supporting β2 association with cholesterol-rich lipid rafts. Indeed, lipid raft labeling confirmed a partial overlap with apical β2. Although β2 palmitoylation was not required to promote surface localization of the α subunit, our data suggest that it is likely implicated in lipid raft association and the polarized localization of β2.
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Affiliation(s)
- Eric Cortada
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), 17190 Salt, Prov. Girona, Spain.,Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 17190 Salt, Prov. Girona, Spain
| | - Robert Serradesanferm
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), 17190 Salt, Prov. Girona, Spain.,Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 17190 Salt, Prov. Girona, Spain
| | - Ramon Brugada
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), 17190 Salt, Prov. Girona, Spain.,Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 17190 Salt, Prov. Girona, Spain.,Medical Sciences Department, University of Girona Medical School, 17071 Girona, Spain.,Cardiology Department, Hospital Josep Trueta - University of Girona Medical School, 17007 Girona, Spain
| | - Marcel Verges
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), 17190 Salt, Prov. Girona, Spain .,Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV), 17190 Salt, Prov. Girona, Spain.,Medical Sciences Department, University of Girona Medical School, 17071 Girona, Spain
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13
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Wen W, Li P, Liu P, Xu S, Wang F, Huang JH. Post-Translational Modifications of BACE1 in Alzheimer's Disease. Curr Neuropharmacol 2021; 20:211-222. [PMID: 33475074 PMCID: PMC9199555 DOI: 10.2174/1570159x19666210121163224] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 11/27/2020] [Accepted: 01/21/2021] [Indexed: 11/23/2022] Open
Abstract
Beta-Amyloid Cleaving Enzyme1 (BACE1) is a monospecific enzyme for the key rate-limiting step in the synthesis of beta-amyloid(Aβ) from cleavage of amyloid precursor protein (APP), to form senile plaques and causes cognitive dysfunction in Alzheimer's disease (AD). Post-translation modifications of BACE1, such as acetylation, glycosylation, palmitoylation, phosphorylation, play a crucial role in the trafficking and maturation process of BACE1. The study of BACE1 is of great importance not only for understanding the formation of toxic Aβ but also for the development of an effective therapeutic target for the treatment of AD. This paper review recent advances in the studies about BACE1, with focuses being paid to the relationship of Aβ, BACE1 with post- translational regulation of BACE1. In addition, we specially reviewed studies about the compounds that can be used to affect post-translational regulation of BACE1 or regulate BACE1 in the literature, which can be used for subsequent research on whether BACE1 is a post-translationally modified drug.
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Affiliation(s)
- Wen Wen
- Institute of Meterial Medica Integration and Transformation for Brain Disorders, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611137. China
| | - Ping Li
- Institute of Meterial Medica Integration and Transformation for Brain Disorders, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611137. China
| | - Panwang Liu
- Institute of Meterial Medica Integration and Transformation for Brain Disorders, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611137. China
| | - Shijun Xu
- Institute of Meterial Medica Integration and Transformation for Brain Disorders, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611137. China
| | - Fushun Wang
- Institute of Brain and Psychological Sciences, Sichuan Normal University, Chengdu, Sichuan 610000. China
| | - Jason H Huang
- Department of Neurosurgery, Baylor Scott & White Health Science Center, Temple, TX 79409. United States
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14
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Syeda T, Cannon JR. Environmental exposures and the etiopathogenesis of Alzheimer's disease: The potential role of BACE1 as a critical neurotoxic target. J Biochem Mol Toxicol 2021; 35:e22694. [PMID: 33393683 DOI: 10.1002/jbt.22694] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 12/18/2020] [Accepted: 12/22/2020] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is a major public health crisis due to devastating cognitive symptoms, a lack of curative treatments, and increasing prevalence. Most cases are sporadic (>95% of cases) after the age of 65 years, implicating an important role of environmental factors in disease pathogenesis. Environmental neurotoxicants have been implicated in neurodegenerative disorders including Parkinson's Disease and AD. Animal models of AD and in vitro studies have shed light on potential neuropathological mechanisms, yet the biochemical and molecular underpinnings of AD-relevant environmental neurotoxicity remain poorly understood. Beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) is a potentially critical pathogenic target of environmentally induced neurotoxicity. BACE1 clearly has a critical role in AD pathophysiology: It is required for amyloid beta production and expression and activity of BACE1 are increased in the AD brain. Though the literature on BACE1 in response to environmental insults is limited, current studies, along with extensive AD neurobiology literature suggest that BACE1 deserves attention as an important neurotoxic target. Here, we critically review research on environmental neurotoxicants such as metals, pesticides, herbicides, fungicides, polyfluoroalkyl substances, heterocyclic aromatic amines, advanced glycation end products, and acrolein that modulate BACE1 and potential mechanisms of action. Though more research is needed to clearly understand whether BACE1 is a critical mediator of AD-relevant neurotoxicity, available reports provide convincing evidence that BACE1 is altered by environmental risk factors associated with AD pathology, implying that BACE1 inhibition and its use as a biomarker should be considered in AD management and research.
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Affiliation(s)
- Tauqeerunnisa Syeda
- School of Health Sciences, Purdue University, West Lafayette, Indiana, USA.,Purdue Institute for Integrative Neurosciences, Purdue University, West Lafayette, Indiana, USA
| | - Jason R Cannon
- School of Health Sciences, Purdue University, West Lafayette, Indiana, USA.,Purdue Institute for Integrative Neurosciences, Purdue University, West Lafayette, Indiana, USA
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15
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Dai Y, Han G, Xu S, Yuan Y, Zhao C, Ma T. Echinacoside Suppresses Amyloidogenesis and Modulates F-actin Remodeling by Targeting the ER Stress Sensor PERK in a Mouse Model of Alzheimer's Disease. Front Cell Dev Biol 2020; 8:593659. [PMID: 33330477 PMCID: PMC7717986 DOI: 10.3389/fcell.2020.593659] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 11/02/2020] [Indexed: 01/23/2023] Open
Abstract
Endoplasmic reticulum stress (ERS) plays a vital and pathogenic role in the onset and progression of Alzheimer’s disease (AD). Phosphorylation of PKR-like endoplasmic reticulum kinase (PERK) induced by ERS depresses the interaction between actin-binding protein filamin-A (FLNA) and PERK, which promotes F-actin accumulation and reduces ER-plasma membrane (PM) communication. Echinacoside (ECH), a pharmacologically active component purified from Cistanche tubulosa, exhibits multiple neuroprotective activities, but the effects of ECH on ERS and F-actin remodeling remain elusive. Here, we found ECH could inhibit the phosphorylation of PERK. Firstly ECH can promote PERK-FLNA combination and modulate F-actin remodeling. Secondly, ECH dramatically decreased cerebral Aβ production and accumulation by inhibiting the translation of BACE1, and significantly ameliorated memory impairment in 2 × Tg-AD mice. Furthermore, ECH exhibited high affinity to either mouse PERK or human PERK. These findings provide novel insights into the neuroprotective actions of ECH against AD, indicating that ECH is a potential therapeutic agent for halting and preventing the progression of AD.
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Affiliation(s)
- Yuan Dai
- Institute of Material Medica Integration and Transformation for Brain Disorders, Chengdu University of Traditional Chinese Medicine, Chengdu, China.,School of Health Preservation and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Guanghui Han
- Dongfang Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Shijun Xu
- Institute of Material Medica Integration and Transformation for Brain Disorders, Chengdu University of Traditional Chinese Medicine, Chengdu, China.,School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Yongna Yuan
- School of Information Science and Engineering, Lanzhou University, Lanzhou, China
| | - Chunyan Zhao
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Tao Ma
- Dongfang Hospital, Beijing University of Chinese Medicine, Beijing, China
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16
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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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17
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Lopez-Font I, Boix CP, Zetterberg H, Blennow K, Sáez-Valero J. Characterization of Cerebrospinal Fluid BACE1 Species. Mol Neurobiol 2019; 56:8603-8616. [PMID: 31290061 DOI: 10.1007/s12035-019-01677-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 06/10/2019] [Indexed: 11/30/2022]
Abstract
The β-site amyloid precursor protein cleaving enzyme 1 (BACE1) is the main brain β-secretase responsible for the amyloidogenic processing of the amyloid precursor protein (APP). Previous studies have suggested that cerebrospinal fluid (CSF) β-secretase activity may be a candidate diagnostic biomarker for Alzheimer's disease (AD), but biochemical characterization of BACE1 protein in CSF is needed. CSF samples from 19 AD patients and 19 age-matched non-AD controls (n = 19) were classified according to their Aβ42, total tau, and P-tau CSF biomarker levels. We found that β-secretase activity was higher in the CSF of AD subjects than in that of the controls. We found that the majority of the β-secretase activity in the CSF, measured using a peptide substrate homologous to the BACE1 cleavage site, was not inhibited by specific BACE1 inhibitors. We defined enzymatic activity attributable specifically to BACE1 as the activity that was blocked by the specific inhibitors, which is still higher in AD subjects. BACE1 protein levels were characterized by lectin binding, immunoprecipitation, blue native-PAGE, and western blotting using antibodies against specific protein domains. BACE1 was found to be present in human CSF as a mature form of ~ 70 kDa that probably comprised truncated and full-length species, and also as an immature form of ~ 50 kDa that retains the prodomain. CSF-BACE1 was found to assemble into hetero-complexes containing distinct species. Immunoblotting with an antibody against the C-terminus of BACE1 revealed significantly higher levels of the 70-kDa full-length BACE1, while the 50 kDa immature form remained unaltered. When the 70-kDa species was probed with an antibody against the N-terminus of BACE1 (which does not discriminate between truncated and full-length forms), no increase in immunoreactivity was observed, suggesting that truncated forms of BACE1 do not increase in AD. In conclusion, the complexity of BACE1 species in CSF has to be taken into consideration when determining BACE1 activity and protein levels in CSF as biomarkers of AD.
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Affiliation(s)
- Inmaculada Lopez-Font
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Av. Ramón y Cajal s/n, E-03550, Sant Joan d'Alacant, Spain. .,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sant Joan d'Alacant, Spain.
| | - Claudia P Boix
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Av. Ramón y Cajal s/n, E-03550, Sant Joan d'Alacant, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sant Joan d'Alacant, Spain
| | - Henrik Zetterberg
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.,Department of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK.,UK Dementia Research Institute at UCL, London, UK
| | - Kaj Blennow
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.,Department of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Javier Sáez-Valero
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Av. Ramón y Cajal s/n, E-03550, Sant Joan d'Alacant, Spain. .,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sant Joan d'Alacant, Spain.
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18
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Ganeshpurkar A, Swetha R, Kumar D, Gangaram GP, Singh R, Gutti G, Jana S, Kumar D, Kumar A, Singh SK. Protein-Protein Interactions and Aggregation Inhibitors in Alzheimer's Disease. Curr Top Med Chem 2019; 19:501-533. [PMID: 30836921 DOI: 10.2174/1568026619666190304153353] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Revised: 10/31/2018] [Accepted: 11/20/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND Alzheimer's Disease (AD), a multifaceted disorder, involves complex pathophysiology and plethora of protein-protein interactions. Thus such interactions can be exploited to develop anti-AD drugs. OBJECTIVE The interaction of dynamin-related protein 1, cellular prion protein, phosphoprotein phosphatase 2A and Mint 2 with amyloid β, etc., studied recently, may have critical role in progression of the disease. Our objective has been to review such studies and their implications in design and development of drugs against the Alzheimer's disease. METHODS Such studies have been reviewed and critically assessed. RESULTS Review has led to show how such studies are useful to develop anti-AD drugs. CONCLUSION There are several PPIs which are current topics of research including Drp1, Aβ interactions with various targets including PrPC, Fyn kinase, NMDAR and mGluR5 and interaction of Mint2 with PDZ domain, etc., and thus have potential role in neurodegeneration and AD. Finally, the multi-targeted approach in AD may be fruitful and opens a new vista for identification and targeting of PPIs in various cellular pathways to find a cure for the disease.
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Affiliation(s)
- Ankit Ganeshpurkar
- Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Rayala Swetha
- Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Devendra Kumar
- Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Gore P Gangaram
- Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Ravi Singh
- Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Gopichand Gutti
- Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Srabanti Jana
- Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Dileep Kumar
- Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Ashok Kumar
- Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
| | - Sushil K Singh
- Pharmaceutical Chemistry Research Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India
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19
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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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20
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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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21
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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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22
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Lichtenthaler SF, Lemberg MK, Fluhrer R. Proteolytic ectodomain shedding of membrane proteins in mammals-hardware, concepts, and recent developments. EMBO J 2018; 37:e99456. [PMID: 29976761 PMCID: PMC6068445 DOI: 10.15252/embj.201899456] [Citation(s) in RCA: 181] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/05/2018] [Accepted: 06/18/2018] [Indexed: 12/14/2022] Open
Abstract
Proteolytic removal of membrane protein ectodomains (ectodomain shedding) is a post-translational modification that controls levels and function of hundreds of membrane proteins. The contributing proteases, referred to as sheddases, act as important molecular switches in processes ranging from signaling to cell adhesion. When deregulated, ectodomain shedding is linked to pathologies such as inflammation and Alzheimer's disease. While proteases of the "a disintegrin and metalloprotease" (ADAM) and "beta-site APP cleaving enzyme" (BACE) families are widely considered as sheddases, in recent years a much broader range of proteases, including intramembrane and soluble proteases, were shown to catalyze similar cleavage reactions. This review demonstrates that shedding is a fundamental process in cell biology and discusses the current understanding of sheddases and their substrates, molecular mechanisms and cellular localizations, as well as physiological functions of protein ectodomain shedding. Moreover, we provide an operational definition of shedding and highlight recent conceptual advances in the field. While new developments in proteomics facilitate substrate discovery, we expect that shedding is not a rare exception, but rather the rule for many membrane proteins, and that many more interesting shedding functions await discovery.
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Affiliation(s)
- Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, Klinikum rechts der Isar, School of Medicine, and Institute for Advanced Study, Technical University Munich, Munich, Germany
- Munich Center for Systems Neurology (SyNergy), Munich, Germany
| | - Marius K Lemberg
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Regina Fluhrer
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Biomedizinisches Centrum (BMC), Ludwig-Maximilians University of Munich, Munich, Germany
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Mañucat-Tan NB, Saadipour K, Wang YJ, Bobrovskaya L, Zhou XF. Cellular Trafficking of Amyloid Precursor Protein in Amyloidogenesis Physiological and Pathological Significance. Mol Neurobiol 2018; 56:812-830. [PMID: 29797184 DOI: 10.1007/s12035-018-1106-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 05/03/2018] [Indexed: 12/26/2022]
Abstract
The accumulation of excess intracellular or extracellular amyloid beta (Aβ) is one of the key pathological events in Alzheimer's disease (AD). Aβ is generated from the cleavage of amyloid precursor protein (APP) by beta secretase-1 (BACE1) and gamma secretase (γ-secretase) within the cells. The endocytic trafficking of APP facilitates amyloidogenesis while at the cell surface, APP is predominantly processed in a non-amyloidogenic manner. Several adaptor proteins bind to both APP and BACE1, regulating their trafficking and recycling along the secretory and endocytic pathways. The phosphorylation of APP at Thr668 and BACE1 at Ser498, also influence their trafficking. Neurotrophins and proneurotrophins also influence APP trafficking through their receptors. In this review, we describe the molecular trafficking pathways of APP and BACE1 that lead to Aβ generation, the involvement of different signaling molecules or adaptor proteins regulating APP and BACE1 subcellular localization. We have also discussed how neurotrophins could modulate amyloidogenesis through their receptors.
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Affiliation(s)
- Noralyn Basco Mañucat-Tan
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, 5000, Australia.
| | - Khalil Saadipour
- Departments of Cell Biology, Physiology and Neuroscience, and Psychiatry, Skirball Institute of Biomolecular Medicine, New York University Langone School of Medicine, New York, NY, USA
| | - Yan-Jiang Wang
- Department of Neurology and Center for Clinical Neuroscience, Daping Hospital, Third Military Medical University, Chongqing, 400042, China
| | - Larisa Bobrovskaya
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, 5000, Australia
| | - Xin-Fu Zhou
- School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, 5000, Australia.
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BACE1 SUMOylation increases its stability and escalates the protease activity in Alzheimer's disease. Proc Natl Acad Sci U S A 2018; 115:3954-3959. [PMID: 29581300 PMCID: PMC5899489 DOI: 10.1073/pnas.1800498115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
BACE1 is a rate-limiting enzyme for amyloid beta polypeptide production, which plays a crucial role in Alzheimer’s disease (AD) pathogenesis. However, how this essential protease is posttranslationally regulated remains incompletely understood. In the current study, we show that K501 residue on BACE1, a ubiquitin modification site, is also competitively SUMOylated. We discovered that SUMOylation of BACE1 augments its stability and enzymatic activity, resulting in senile plaque formation and cognitive defect. Identification of the posttranslational modification on BACE1 provides insight into the molecular mechanism in AD. Amyloid beta (Aβ) is a major pathological marker in Alzheimer’s disease (AD), which is principally regulated by the rate-limiting β-secretase (i.e., BACE1) cleavage of amyloid precursor protein (APP). However, how BACE1 activity is posttranslationally regulated remains incompletely understood. Here, we show that BACE1 is predominantly SUMOylated at K501 residue, which escalates its protease activity and stability and subsequently increases Aβ production, leading to cognitive defect seen in the AD mouse model. Compared with a non-SUMOylated K501R mutant, injection of wild-type BACE1 significantly increases Aβ production and triggers cognitive dysfunction. Furthermore, overexpression of wild-type BACE1, but not non-SUMOylated K501R mutant, facilitates senile plaque formation and aggravates the cognitive deficit seen in the APP/PS1 AD mouse model. Together, our data strongly suggest that K501 SUMOylation on BACE1 plays a critical role in mediating its stability and enzymatic activity.
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BACE1 Function and Inhibition: Implications of Intervention in the Amyloid Pathway of Alzheimer's Disease Pathology. Molecules 2017; 22:molecules22101723. [PMID: 29027981 PMCID: PMC6151801 DOI: 10.3390/molecules22101723] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/09/2017] [Accepted: 10/10/2017] [Indexed: 01/18/2023] Open
Abstract
Alzheimer's disease (AD) is a fatal progressive neurodegenerative disorder characterized by increasing loss in memory, cognition, and function of daily living. Among the many pathologic events observed in the progression of AD, changes in amyloid β peptide (Aβ) metabolism proceed fastest, and precede clinical symptoms. BACE1 (β-secretase 1) catalyzes the initial cleavage of the amyloid precursor protein to generate Aβ. Therefore inhibition of BACE1 activity could block one of the earliest pathologic events in AD. However, therapeutic BACE1 inhibition to block Aβ production may need to be balanced with possible effects that might result from diminished physiologic functions BACE1, in particular processing of substrates involved in neuronal function of the brain and periphery. Potentials for beneficial or consequential effects resulting from pharmacologic inhibition of BACE1 are reviewed in context of ongoing clinical trials testing the effect of BACE1 candidate inhibitor drugs in AD populations.
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26
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Alzheimer disease: modeling an Aβ-centered biological network. Mol Psychiatry 2016; 21:861-71. [PMID: 27021818 DOI: 10.1038/mp.2016.38] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/16/2016] [Accepted: 02/18/2016] [Indexed: 01/15/2023]
Abstract
In genetically complex diseases, the search for missing heritability is focusing on rare variants with large effect. Thanks to next generation sequencing technologies, genome-wide characterization of these variants is now feasible in every individual. However, a lesson from current studies is that collapsing rare variants at the gene level is often insufficient to obtain a statistically significant signal in case-control studies, and that network-based analyses are an attractive complement to classical approaches. In Alzheimer disease (AD), according to the prevalent amyloid cascade hypothesis, the pathology is driven by the amyloid beta (Aβ) peptide. In past years, based on experimental studies, several hundreds of proteins have been shown to interfere with Aβ production, clearance, aggregation or toxicity. Thanks to a manual curation of the literature, we identified 335 genes/proteins involved in this biological network and classified them according to their cellular function. The complete list of genes, or its subcomponents, will be of interest in ongoing AD genetic studies.
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Deposition of BACE-1 Protein in the Brains of APP/PS1 Double Transgenic Mice. BIOMED RESEARCH INTERNATIONAL 2016; 2016:8380618. [PMID: 27294139 PMCID: PMC4887654 DOI: 10.1155/2016/8380618] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/13/2016] [Accepted: 04/17/2016] [Indexed: 11/30/2022]
Abstract
The main causes of Alzheimer's disease remain elusive. Previous data have implicated the BACE-1 protein as a central player in the pathogenesis of Alzheimer's disease. However, many inhibitors of BACE-1 have failed during preclinical and clinical trials for AD treatment. Therefore, uncovering the exact role of BACE-1 in AD may have significant impact on the future development of therapeutic agents. Three- and six-month-old female APP/PS1 double transgenic mice were used to study abnormal accumulation of BACE-1 protein in brains of mice here. Immunofluorescence, immunohistochemistry, and western blot were performed to measure the distributing pattern and expression level of BACE-1. We found obvious BACE-1 protein accumulation in 3-month-old APP/PS1 mice, which had increased by the time of 6 months. Coimmunostaining results showed BACE-1 surrounded amyloid plaques in brain sections. The abnormal protein expression might not be attributable to the upregulation of BACE-1 protein, as no significant difference of protein expression was observed between wild-type and APP/PS1 mice. With antibodies against BACE-1 and CD31, we found a high immunoreactive density of BACE-1 protein on the outer layer of brain blood vessels. The aberrant distribution of BACE-1 in APP/PS1 mice suggests BACE-1 may be involved in the microvascular abnormality of AD.
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Post-translational regulation of the β-secretase BACE1. Brain Res Bull 2016; 126:170-177. [PMID: 27086128 DOI: 10.1016/j.brainresbull.2016.04.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 04/08/2016] [Accepted: 04/12/2016] [Indexed: 11/21/2022]
Abstract
β-Secretase, widely known as β-site APP cleaving enzyme 1 (BACE1), is a membrane-associated protease that cleaves amyloid precursor protein (APP) to generate amyloid β-protein (Aβ). As this cleavage is a pathologically relevant event in Alzheimer's disease, BACE1 is considered a viable therapeutic target. BACE1 can be regulated at the transcriptional, post-transcriptional, translational, and post-translational levels. Elucidation of the regulatory pathways of BACE1 is critical, not only for understanding the pathological mechanisms of AD but also developing effective therapeutic strategies to inhibit activity of the protease. This mini-review focuses on the post-translational regulation of BACE1, as modulation at this level is closely associated with both physiological and pathological conditions. Current knowledge on the mechanisms underlying such BACE1 regulation and their implications for therapy are discussed.
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Vergés M. Retromer in Polarized Protein Transport. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 323:129-79. [PMID: 26944621 DOI: 10.1016/bs.ircmb.2015.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Retromer is an evolutionary conserved protein complex required for endosome-to-Golgi retrieval of receptors for lysosomal hydrolases. It is constituted by a heterotrimer encoded by the vacuolar protein sorting (VPS) gene products Vps26, Vps35, and Vps29, which selects cargo, and a dimer of phosphoinositide-binding sorting nexins, which deforms the membrane. Recent progress in the mechanism of retromer assembly and functioning has strengthened the link between sorting at the endosome and cytoskeleton dynamics. Retromer is implicated in endosomal sorting of many cargos and plays an essential role in plant and animal development. Although it is best known for endosome sorting to the trans-Golgi network, it also intervenes in recycling to the plasma membrane. In polarized cells, such as epithelial cells and neurons, retromer may also be utilized for transcytosis and long-range transport. Considerable evidence implicates retromer in establishment and maintenance of cell polarity. That includes sorting of the apical polarity module Crumbs; regulation of retromer function by the basolateral polarity module Scribble; and retromer-dependent recycling of various cargoes to a certain surface domain, thus controlling polarized location and cell homeostasis. Importantly, altered retromer function has been linked to neurodegeneration, such as in Alzheimer's or Parkinson's disease. This review will underline how alterations in retromer localization and function may affect polarized protein transport and polarity establishment, thereby causing developmental defects and disease.
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Affiliation(s)
- Marcel Vergés
- Cardiovascular Genetics Group, Girona Biomedical Research Institute (IDIBGI), Girona, Spain; Medical Sciences Department, University of Girona, Girona, Spain.
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Fleck D, Voss M, Brankatschk B, Giudici C, Hampel H, Schwenk B, Edbauer D, Fukumori A, Steiner H, Kremmer E, Haug-Kröper M, Rossner MJ, Fluhrer R, Willem M, Haass C. Proteolytic Processing of Neuregulin 1 Type III by Three Intramembrane-cleaving Proteases. J Biol Chem 2015; 291:318-33. [PMID: 26574544 DOI: 10.1074/jbc.m115.697995] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Indexed: 12/22/2022] Open
Abstract
Numerous membrane-bound proteins undergo regulated intramembrane proteolysis. Regulated intramembrane proteolysis is initiated by shedding, and the remaining stubs are further processed by intramembrane-cleaving proteases (I-CLiPs). Neuregulin 1 type III (NRG1 type III) is a major physiological substrate of β-secretase (β-site amyloid precursor protein-cleaving enzyme 1 (BACE1)). BACE1-mediated cleavage is required to allow signaling of NRG1 type III. Because of the hairpin nature of NRG1 type III, two membrane-bound stubs with a type 1 and a type 2 orientation are generated by proteolytic processing. We demonstrate that these stubs are substrates for three I-CLiPs. The type 1-oriented stub is further cleaved by γ-secretase at an ϵ-like site five amino acids N-terminal to the C-terminal membrane anchor and at a γ-like site in the middle of the transmembrane domain. The ϵ-cleavage site is only one amino acid N-terminal to a Val/Leu substitution associated with schizophrenia. The mutation reduces generation of the NRG1 type III β-peptide as well as reverses signaling. Moreover, it affects the cleavage precision of γ-secretase at the γ-site similar to certain Alzheimer disease-associated mutations within the amyloid precursor protein. The type 2-oriented membrane-retained stub of NRG1 type III is further processed by signal peptide peptidase-like proteases SPPL2a and SPPL2b. Expression of catalytically inactive aspartate mutations as well as treatment with 2,2'-(2-oxo-1,3-propanediyl)bis[(phenylmethoxy)carbonyl]-l-leucyl-l-leucinamide ketone inhibits formation of N-terminal intracellular domains and the corresponding secreted C-peptide. Thus, NRG1 type III is the first protein substrate that is not only cleaved by multiple sheddases but is also processed by three different I-CLiPs.
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Affiliation(s)
- Daniel Fleck
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Matthias Voss
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Ben Brankatschk
- the Department of Molecular Neurobiology, Clinic for Psychiatry, Ludwig-Maximilians-University Munich, 80336 Munich
| | - Camilla Giudici
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Heike Hampel
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Benjamin Schwenk
- the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich
| | - Dieter Edbauer
- the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich, the Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, and
| | - Akio Fukumori
- the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich
| | - Harald Steiner
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich
| | - Elisabeth Kremmer
- the Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, and the Institute of Molecular Immunology, Helmholtz Center Munich, 81377 Munich, Germany
| | - Martina Haug-Kröper
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Moritz J Rossner
- the Department of Molecular Neurobiology, Clinic for Psychiatry, Ludwig-Maximilians-University Munich, 80336 Munich
| | - Regina Fluhrer
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich
| | - Michael Willem
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich,
| | - Christian Haass
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich, the Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, and
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The Association of Amyloid-β Protein Precursor With α- and β-Secretases in Mouse Cerebral Cortex Synapses Is Altered in Early Alzheimer’s Disease. Mol Neurobiol 2015; 53:5710-21. [DOI: 10.1007/s12035-015-9491-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 10/14/2015] [Indexed: 10/22/2022]
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Structural insight into the mechanism of amyloid precursor protein recognition by β-secretase 1: A molecular dynamics study. Biophys Chem 2015; 202:1-12. [DOI: 10.1016/j.bpc.2015.03.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/08/2015] [Accepted: 03/09/2015] [Indexed: 02/06/2023]
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Kandalepas PC, Vassar R. The normal and pathologic roles of the Alzheimer's β-secretase, BACE1. Curr Alzheimer Res 2015; 11:441-9. [PMID: 24893886 DOI: 10.2174/1567205011666140604122059] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 01/15/2014] [Accepted: 01/25/2014] [Indexed: 01/18/2023]
Abstract
As the most common neurodegenerative disease, therapeutic avenues for the treatment and prevention of Alzheimer's Disease are highly sought after. The aspartic protease BACE1 is the initiator enzyme for the formation of Aβ, a major constituent of amyloid plaques that represent one of the hallmark pathological features of this disorder. Thus, targeting BACE1 for disease-modifying AD therapies represents a rationale approach. The collective knowledge acquired from investigations of BACE1 deletion mutants and characterization of BACE1 substrates has downstream significance not only for the discovery of AD drug therapies but also for predicting side effects of BACE1 inhibition. Here we discuss the identification and validation of BACE1 as the β-secretase implicated in AD, in addition to information regarding BACE1 cell biology, localization, substrates and potential physiological functions derived from BACE1 knockout models.
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Affiliation(s)
| | - Robert Vassar
- Northwestern University, Feinberg School of Medicine, Department of Cell & Molecular Biology, 300 E. Superior, Tarry 8-713, IL 60611, Chicago.
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Abstract
Increased amyloid beta (Aβ) production by sequential cleavage of the amyloid precursor protein (APP) by the β- and γ-secretases contributes to the etiological basis of Alzheimer's disease (AD). This process requires APP and the secretases to be in the same subcellular compartments, such as the endosomes. Since all membrane organelles in the endomembrane system are kinetically and functionally linked, any defects in the trafficking and sorting machinery would be expected to change the functional properties of the whole system. The Golgi is a primary organelle for protein trafficking, sorting and modifications, and Golgi defects have been reported in AD. Here we hypothesize that Golgi fragmentation in AD accelerates APP trafficking and Aβ production. Furthermore, Golgi defects may perturb the proper trafficking and processing of many essential neuronal proteins, resulting in compromised neuronal function. Therefore, molecular tools that can restore Golgi structure and function could prove useful as potential drugs for AD treatment.
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Affiliation(s)
- Gunjan Joshi
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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Joshi G, Gan KA, Johnson DA, Johnson JA. Increased Alzheimer's disease-like pathology in the APP/ PS1ΔE9 mouse model lacking Nrf2 through modulation of autophagy. Neurobiol Aging 2014; 36:664-79. [PMID: 25316599 DOI: 10.1016/j.neurobiolaging.2014.09.004] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 07/01/2014] [Accepted: 09/01/2014] [Indexed: 12/21/2022]
Abstract
The presence of senile plaques is one of the major pathologic hallmarks of the brain with Alzheimer's disease (AD). The plaques predominantly contain insoluble amyloid β-peptide, a cleavage product of the larger amyloid precursor protein (APP). Two enzymes, named β and γ secretase, generate the neurotoxic amyloid-β peptide from APP. Mature APP is also turned over endogenously by autophagy, more specifically by the endosomal-lysosomal pathway. A defective lysosomal system is known to be pathogenic in AD. Modulation of NF-E2 related factor 2 (Nrf2) has been shown in several neurodegenerative disorders, and Nrf2 has become a potential therapeutic target for various neurodegenerative disorders, including AD, Parkinson's disease, and amyotrophic lateral sclerosis. In the current study, we explored the effect of genetic ablation of Nrf2 on APP/Aβ processing and/or aggregation as well as changes in autophagic dysfunction in APP/PS1 mice. There was a significant increase in inflammatory response in APP/PS1 mice lacking Nrf2. This was accompanied by increased intracellular levels of APP, Aβ (1-42), and Aβ (1-40), without a change total full-length APP. There was a shift of APP and Aβ into the insoluble fraction, as well as increased poly-ubiquitin conjugated proteins in mice lacking Nrf2. APP/PS1-mediated autophagic dysfunction is also enhanced in Nrf2-deficient mice. Finally, neurons in the APP/PS1/Nrf2-/- mice had increased accumulation of multivesicular bodies, endosomes, and lysosomes. These outcomes provide a better understanding of the role of Nrf2 in modulating autophagy in an AD mouse model and may help design better Nrf2 targeted therapeutics that could be efficacious in the treatment of AD.
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Affiliation(s)
- Gururaj Joshi
- School of Pharmacy, University of Wisconsin-Madison, WI, USA
| | - Kok Ann Gan
- School of Pharmacy, University of Wisconsin-Madison, WI, USA
| | - Delinda A Johnson
- School of Pharmacy, University of Wisconsin-Madison, WI, USA; Center of Neuroscience, University of Wisconsin-Madison, WI, USA; Waisman Center, University of Wisconsin-Madison, WI, USA
| | - Jeffrey A Johnson
- School of Pharmacy, University of Wisconsin-Madison, WI, USA; Molecular and Environmental Toxicology Center, University of Wisconsin-Madison, WI, USA; Center of Neuroscience, University of Wisconsin-Madison, WI, USA; Waisman Center, University of Wisconsin-Madison, WI, USA.
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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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Vassar R, Kuhn PH, Haass C, Kennedy ME, Rajendran L, Wong PC, Lichtenthaler SF. Function, therapeutic potential and cell biology of BACE proteases: current status and future prospects. J Neurochem 2014; 130:4-28. [PMID: 24646365 PMCID: PMC4086641 DOI: 10.1111/jnc.12715] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 03/12/2014] [Accepted: 03/14/2014] [Indexed: 01/18/2023]
Abstract
The β-site APP cleaving enzymes 1 and 2 (BACE1 and BACE2) were initially identified as transmembrane aspartyl proteases cleaving the amyloid precursor protein (APP). BACE1 is a major drug target for Alzheimer's disease because BACE1-mediated cleavage of APP is the first step in the generation of the pathogenic amyloid-β peptides. BACE1, which is highly expressed in the nervous system, is also required for myelination by cleaving neuregulin 1. Several recent proteomic and in vivo studies using BACE1- and BACE2-deficient mice demonstrate a much wider range of physiological substrates and functions for both proteases within and outside of the nervous system. For BACE1 this includes axon guidance, neurogenesis, muscle spindle formation, and neuronal network functions, whereas BACE2 was shown to be involved in pigmentation and pancreatic β-cell function. This review highlights the recent progress in understanding cell biology, substrates, and functions of BACE proteases and discusses the therapeutic options and potential mechanism-based liabilities, in particular for BACE inhibitors in Alzheimer's disease. The protease BACE1 is a major drug target in Alzheimer disease. Together with its homolog BACE2, both proteases have an increasing number of functions within and outside of the nervous system. This review highlights recent progress in understanding cell biology, substrates, and functions of BACE proteases and discusses the therapeutic options and potential mechanism-based liabilities, in particular for BACE inhibitors in Alzheimer disease.
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Affiliation(s)
- Robert Vassar
- Department of Cell and Molecular Biology, Feinberg University School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Peer-Hendrik Kuhn
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Institute for Advanced Study, Technische Universität München, Garching, Germany
| | - Christian Haass
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
- Adolf-Butenandt Institute, Biochemistry, Ludwig-Maximilians University Munich, Munich, Germany
| | - Matthew E. Kennedy
- Neurosciences, Merck Research Labs, Boston, Massachusetts, USA
- Division of Psychiatry Research, University of Zurich, Zurich, Switzerland
| | - Lawrence Rajendran
- Systems and Cell Biology of Neurodegeneration, Division of Psychiatry Research, University of Zurich, Zurich, Switzerland
- Graduate programs of the Zurich Center for Integrative Human Physiology and Zurich Neuroscience Center, University of Zurich, Zurich, Switzerland
| | - Philip C. Wong
- Departments of Pathology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Stefan F. Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
- Neuroproteomics, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Institute for Advanced Study, Technische Universität München, Garching, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
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Mocali A, Della Malva N, Abete C, Mitidieri Costanza VA, Bavazzano A, Boddi V, Sanchez L, Dessì S, Pani A, Paoletti F. Altered proteolysis in fibroblasts of Alzheimer patients with predictive implications for subjects at risk of disease. Int J Alzheimers Dis 2014; 2014:520152. [PMID: 24949214 PMCID: PMC4052202 DOI: 10.1155/2014/520152] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 04/09/2014] [Accepted: 05/04/2014] [Indexed: 02/04/2023] Open
Abstract
There is great interest in developing reliable biomarkers to support antemortem diagnosis of late-onset Alzheimer's disease (AD). Early prediction and diagnosis of AD might be improved by the detection of a proteolytic dysfunction in extracts from cultured AD fibroblasts, producing altered isoelectrophoretic forms of the enzyme transketolase (TK-alkaline bands). The TK profile and apolipoprotein E (APOE) genotype were examined in fibroblasts from 36 clinically diagnosed probable late-onset sporadic AD patients and 38 of their asymptomatic relatives, 29 elderly healthy individuals, 12 neurological non-AD patients, and 5 early-onset AD patients. TK alterations occurred in (i) several probable AD patients regardless of age-of-onset and severity of disease; (ii) all early-onset AD patients and APOE ε 4/4 carriers; and (iii) nearly half of asymptomatic AD relatives. Normal subjects and non-AD patients were all negative. Notably, culture conditions promoting TK alterations were also effective in increasing active BACE1 levels. Overall, the TK assay might represent a low-cost laboratory tool useful for supporting AD differential diagnosis and identifying asymptomatic subjects who are at greater risk of AD and who should enter a follow-up study. Moreover, the cultured fibroblasts were confirmed as a useful in vitro model for further studies on the pathogenetic process of AD.
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Affiliation(s)
- Alessandra Mocali
- Section of Experimental Pathology and Oncology, Department of Biomedical Experimental and Clinical Sciences, University of Florence, 50134 Florence, Italy
| | - Nunzia Della Malva
- Section of Experimental Pathology and Oncology, Department of Biomedical Experimental and Clinical Sciences, University of Florence, 50134 Florence, Italy
| | - Claudia Abete
- Department of Internal Medicine, University of Cagliari, 09042 Monserrato, Italy
| | | | | | - Vieri Boddi
- Department of Public Health, University of Florence, 50134 Florence, Italy
| | - Luis Sanchez
- 1st Unit of General Surgery and Transplantation, Careggi Hospital, 50134 Florence, Italy
| | - Sandra Dessì
- Department of Internal Medicine, University of Cagliari, 09042 Monserrato, Italy
| | - Alessandra Pani
- Department of Biomedical Sciences, University of Cagliari, 09042 Monserrato, Italy
| | - Francesco Paoletti
- Section of Experimental Pathology and Oncology, Department of Biomedical Experimental and Clinical Sciences, University of Florence, 50134 Florence, Italy
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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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40
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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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41
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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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42
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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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43
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Chia PZC, Toh WH, Sharples R, Gasnereau I, Hill AF, Gleeson PA. Intracellular itinerary of internalised β-secretase, BACE1, and its potential impact on β-amyloid peptide biogenesis. Traffic 2013; 14:997-1013. [PMID: 23773724 DOI: 10.1111/tra.12088] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 06/11/2013] [Accepted: 06/14/2013] [Indexed: 01/17/2023]
Abstract
β-Secretase (BACE1) cleavage of the amyloid precursor protein (APP) represents the initial step in the formation of the Alzheimer's disease associated amyloidogenic Aβ peptide. Substantive evidence indicates that APP processing by BACE1 is dependent on intracellular sorting of this enzyme. Nonetheless, knowledge of the intracellular trafficking pathway of internalised BACE1 remains in doubt. Here we show that cell surface BACE1 is rapidly internalised by the AP2/clathrin dependent pathway in transfected cells and traffics to early endosomes and Rab11-positive, juxtanuclear recycling endosomes, with very little transported to the TGN as has been previously suggested. Moreover, BACE1 is predominantly localised to the early and recycling endosome compartments in different cell types, including neuronal cells. In contrast, the majority of internalised wild-type APP traffics to late endosomes/lysosomes. To explore the relevance of the itinerary of BACE1 on APP processing, we generated a BACE1 chimera containing the cytoplasmic tail of TGN38 (BACE/TGN38), which cycles between the cell surface and TGN in an AP2-dependent manner. Wild-type BACE1 is less efficient in Aβ production than the BACE/TGN38 chimera, highlighting the relevance of the itinerary of BACE1 on APP processing. Overall the data suggests that internalised BACE1 and APP diverge at early endosomes and that Aβ biogenesis is regulated in part by the recycling itinerary of BACE1.
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Affiliation(s)
- Pei Zhi Cheryl Chia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
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Dual cleavage of neuregulin 1 type III by BACE1 and ADAM17 liberates its EGF-like domain and allows paracrine signaling. J Neurosci 2013; 33:7856-69. [PMID: 23637177 DOI: 10.1523/jneurosci.3372-12.2013] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Proteolytic shedding of cell surface proteins generates paracrine signals involved in numerous signaling pathways. Neuregulin 1 (NRG1) type III is involved in myelination of the peripheral nervous system, for which it requires proteolytic activation by proteases of the ADAM family and BACE1. These proteases are major therapeutic targets for the prevention of Alzheimer's disease because they are also involved in the proteolytic generation of the neurotoxic amyloid β-peptide. Identification and functional investigation of their physiological substrates is therefore of greatest importance in preventing unwanted side effects. Here we investigated proteolytic processing of NRG1 type III and demonstrate that the ectodomain can be cleaved by three different sheddases, namely ADAM10, ADAM17, and BACE1. Surprisingly, we not only found cleavage by ADAM10, ADAM17, and BACE1 C-terminal to the epidermal growth factor (EGF)-like domain, which is believed to play a pivotal role in signaling, but also additional cleavage sites for ADAM17 and BACE1 N-terminal to that domain. Proteolytic processing at N- and C-terminal sites of the EGF-like domain results in the secretion of this domain from NRG1 type III. The soluble EGF-like domain is functionally active and stimulates ErbB3 signaling in tissue culture assays. Moreover, the soluble EGF-like domain is capable of rescuing hypomyelination in a zebrafish mutant lacking BACE1. Our data suggest that NRG1 type III-dependent myelination is not only controlled by membrane-retained NRG1 type III, but also in a paracrine manner via proteolytic liberation of the EGF-like domain.
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45
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Shen Y. From Bench to Bedside. Bioinformatics 2013. [DOI: 10.4018/978-1-4666-3604-0.ch017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Alzheimer’s disease (AD) is a constantly progressive and highly complex neurodegenerative disease, and there are many ways to molecularly characterize the various stages. Morphologically, AD patients are characterized by neurofibrillar abnormalities associated with pathological hyperphosphorylation of tau protein, and deposits of ß– amyloid peptides (Aß). There is an overwhelming amount of information to support the hypothesis that generation, formation, and ß-amyloid deposits play key mechanistic roles in the early development of AD. It is known that the cause of early-onset familial AD (FAD) is due to mutations in three genes which cause an increase in the production of the toxic peptide, Aß42. The molecules that cause the proteolytic activities of beta and gamma secretase, two proteases that free the Aß-peptide by endoproteolyzing APP, have recently been discovered. Homologous to BACE1, BACE2 was also a recent discovery (Lin et al, 2000; Vassar et al, 1999; Yan et al, 1999), and together these two enzymes make up a new family of transmembrane aspartic proteases. The key enzyme, BACE1, initiates the formation of Aß, represents a candidate biomarker, as well as a drug target for AD, exhibit all the functional properties of ß–secretase. This chapter will review the biology of BACE1 and focus attention to BACE1 as a candidate biomarker for the early detection, prediction, and biological activity in AD.
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Affiliation(s)
- Yong Shen
- Center for Advanced Therapeutic Strategies for Brain Disorders, Raskamp Institute, USA
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46
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Wang H, Li R, Shen Y. β-Secretase: its biology as a therapeutic target in diseases. Trends Pharmacol Sci 2013; 34:215-25. [PMID: 23452816 DOI: 10.1016/j.tips.2013.01.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 01/21/2013] [Accepted: 01/29/2013] [Indexed: 11/24/2022]
Abstract
β-Secretase (BACE1, β-site APP cleaving enzyme 1) is an aspartic proteinase that has multiple functions in various physiological processes, such as cell differentiation, immunoregulation, and cell death. There is increasing evidence that changes in BACE1 activity are involved in many diseases, such as Alzheimer's disease (AD), schizophrenia, epileptic behavior, and others. However, a deeper understanding of the molecular biology of BACE1 is necessary for further exploration of cell development, immunological regulation, and disease pathogenesis. Here, we review the molecular and cellular biology of BACE1, including its enzymatic properties, structure, biosynthesis, and physiological functions to provide a new perspective and rational assessment of drugability. Lastly, we discuss proposed strategies to control BACE1 activity for possible therapeutic application.
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Affiliation(s)
- Haibo Wang
- Center for Advanced Therapeutic Strategies for Brain Disorders, Roskamp Institute, Sarasota, FL 34203, USA
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47
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Chen S, Ge X, Chen Y, Lv N, Liu Z, Yuan W. Advances with RNA interference in Alzheimer's disease research. DRUG DESIGN DEVELOPMENT AND THERAPY 2013; 7:117-25. [PMID: 23459401 PMCID: PMC3582316 DOI: 10.2147/dddt.s40229] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized clinically by memory and cognitive dysfunction. Unfortunately, there is no effective therapeutic method for AD treatment or ways to halt disease progression. Many mechanisms are involved in the disease, including genes mutation and protein dysfunction. RNA interference (RNAi) technology may potentially be able to control AD. It can inhibit the protein expression of specific genes by activating a sequence-specific RNA degradation process. This is a powerful tool with which to study gene function, investigate the mechanism of the disease, and validate drug targets. In this review, we highlight the advances in RNAi technology in the investigation and treatment of AD.
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Affiliation(s)
- Shun Chen
- Department of Neurology, Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine, Shanghai Jiaotong University, Shanghai
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48
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Tamagno E, Guglielmotto M, Monteleone D, Vercelli A, Tabaton M. Transcriptional and post-transcriptional regulation of β-secretase. IUBMB Life 2012. [DOI: 10.1002/iub.1099] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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49
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Holsinger RMD, Goense N, Bohorquez J, Strappe P. Splice variants of the Alzheimer's disease beta-secretase, BACE1. Neurogenetics 2012; 14:1-9. [PMID: 23142975 DOI: 10.1007/s10048-012-0348-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 10/15/2012] [Indexed: 10/27/2022]
Abstract
Cleavage of the amyloid precursor protein by enzymes commonly referred to as β- and γ-secretase constitute an important process in the pathogenesis of Alzheimer's disease (AD). The regulation of this process is therefore an important subject of investigation. Numerous sources of endogenous regulation have been identified, and one of these is the relative abundance and regulation of splice variants of the β-secretase, BACE1 (β-site amyloid precursor protein cleaving enzyme 1). In this review, we will briefly discuss the main characteristics of BACE1, review the different variants of this enzyme that have been identified to date, and highlight their possible implication in AD.
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Affiliation(s)
- R M Damian Holsinger
- Laboratory of Molecular Neuroscience, Brain and Mind Research Institute, The University of Sydney, Camperdown, NSW 2050, Australia.
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50
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Cuartero Y, Mellado M, Capell A, Álvarez-Dolado M, Verges M. Retromer Regulates Postendocytic Sorting of β-Secretase in Polarized Madin-Darby Canine Kidney Cells. Traffic 2012; 13:1393-410. [DOI: 10.1111/j.1600-0854.2012.01392.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 06/28/2012] [Accepted: 07/03/2012] [Indexed: 01/24/2023]
Affiliation(s)
- Yasmina Cuartero
- Laboratory of Epithelial Cell Biology; Centro de Investigación Príncipe Felipe; Valencia; Spain
| | - Maravillas Mellado
- Laboratory of Epithelial Cell Biology; Centro de Investigación Príncipe Felipe; Valencia; Spain
| | - Anja Capell
- German Center for Neurodegenerative Diseases & Adolf Butenandt Institute - Biochemistry; Ludwig Maximilians University; Munich; Germany
| | - Manuel Álvarez-Dolado
- Department of Cell Therapy and Regenerative Medicine; Andalusian Center for Molecular Biology and Regenerative Medicine; Seville; Spain
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