101
|
Sialylated glycosylphosphatidylinositols suppress the production of toxic amyloid-β oligomers. Biochem J 2017; 474:3045-3058. [PMID: 28729427 DOI: 10.1042/bcj20170239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 07/07/2017] [Accepted: 07/19/2017] [Indexed: 01/30/2023]
Abstract
The production of amyloid-β (Aβ) is a key factor driving pathogenesis in Alzheimer's disease (AD). Increasing concentrations of soluble Aβ oligomers within the brain lead to synapse degeneration and the progressive dementia characteristic of AD. Since Aβ exists in both disease-relevant (toxic) and non-toxic forms, the factors that affected the release of toxic Aβ were studied in a cell model. 7PA2 cells expressing the human amyloid precursor protein released Aβ oligomers that caused synapse damage when incubated with cultured neurones. These Aβ oligomers had similar potency to soluble Aβ oligomers derived from the brains of Alzheimer's patients. Although the conditioned media from 7PA2 cells treated with the cellular prion protein (PrPC) contained Aβ, it did not cause synapse damage. The loss of toxicity was associated with a reduction in Aβ oligomers and an increase in Aβ monomers. The suppression of toxic Aβ release was dependent on the glycosylphosphatidylinositol (GPI) anchor attached to PrPC, and treatment of cells with specific GPIs alone reduced the production of toxic Aβ. The efficacy of GPIs was structure-dependent and the presence of sialic acid was critical. The conditioned medium from GPI-treated cells protected neurones against Aβ oligomer-induced synapse damage; neuroprotection was mediated by Aβ monomers. These studies support the hypothesis that the ratio of Aβ monomers to Aβ oligomers is a critical factor that regulates synapse damage.
Collapse
|
102
|
Jayne T, Newman M, Verdile G, Sutherland G, Münch G, Musgrave I, Moussavi Nik SH, Lardelli M. Evidence For and Against a Pathogenic Role of Reduced γ-Secretase Activity in Familial Alzheimer's Disease. J Alzheimers Dis 2017; 52:781-99. [PMID: 27060961 DOI: 10.3233/jad-151186] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The majority of mutations causing familial Alzheimer's disease (fAD) have been found in the gene PRESENILIN1 (PSEN1) with additional mutations in the related gene PRESENILIN2 (PSEN2). The best characterized function of PRESENILIN (PSEN) proteins is in γ-secretase enzyme activity. One substrate of γ-secretase is encoded by the gene AMYLOID BETA A4 PRECURSOR PROTEIN (AβPP/APP) that is a fAD mutation locus. AβPP is the source of the amyloid-β (Aβ) peptide enriched in the brains of people with fAD or the more common, late onset, sporadic form of AD, sAD. These observations have resulted in a focus on γ-secretase activity and Aβ as we attempt to understand the molecular basis of AD pathology. In this paper we briefly review some of the history of research on γ-secretase in AD. We then discuss the main ideas regarding the role of γ-secretase and the PSEN genes in this disease. We examine the significance of the "fAD mutation reading frame preservation rule" that applies to PSEN1 and PSEN2 (and AβPP) and look at alternative roles for AβPP and Aβ in fAD. We present a case for an alternative interpretation of published data on the role of γ-secretase activity and fAD-associated mutations in AD pathology. Evidence supports a "PSEN holoprotein multimer hypothesis" where PSEN fAD mutations generate mutant PSEN holoproteins that multimerize with wild type holoprotein and dominantly interfere with an AD-critical function(s) such as autophagy or secretion of Aβ. Holoprotein multimerization may be required for the endoproteolysis that activates PSENs' γ-secretase activity.
Collapse
Affiliation(s)
- Tanya Jayne
- Alzheimer's Disease Genetics Laboratory, Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide SA, Australia
| | - Morgan Newman
- Alzheimer's Disease Genetics Laboratory, Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide SA, Australia
| | - Giuseppe Verdile
- School of Biomedical Sciences, Curtin Health Innovation Research Institute - Biosciences, Faculty of Health Sciences, Curtin University, Kent Street, Bentley, WA, Australia.,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, WA, Australia.,McCusker Alzheimer's Disease Research Foundation, Hollywood Private Hospital, Hollywood Medical Centre, Nedlands, WA, Australia
| | - Greg Sutherland
- Discipline of Pathology, Charles Perkins Centre, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Gerald Münch
- Molecular Medicine Research Group & School of Medicine, Western Sydney University, Campbelltown NSW, Australia
| | - Ian Musgrave
- Discipline of Pharmacology, School of Medicine, University of Adelaide, North Terrace, Adelaide, SA, Australia
| | - Seyyed Hani Moussavi Nik
- Alzheimer's Disease Genetics Laboratory, Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide SA, Australia
| | - Michael Lardelli
- Alzheimer's Disease Genetics Laboratory, Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide SA, Australia
| |
Collapse
|
103
|
Wang C, Chen P, He X, Peng Z, Chen S, Zhang R, Cheng J, Liu Q. Direct interaction between selenoprotein R and Aβ42. Biochem Biophys Res Commun 2017; 489:509-514. [PMID: 28579431 DOI: 10.1016/j.bbrc.2017.05.182] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 05/31/2017] [Indexed: 01/15/2023]
Abstract
Amyloid-β (Aβ) peptides have taken a central role in AD research, the aggregation of Aβ peptide is involved in the progression of Alzheimer's disease (AD). The 35th amino acid was methionine (Met) in Aβ peptides and it's redox state is critical in determining the biological activity of Aβ. It has been suggested that oxidation of Met35 (Met35O) plays a key role in the formation of paranuclei and in the control of oligomerization pathway choice. As an antioxidative selenoenzyme, Selenoprotein R (SelR) plays important roles in reducing the R-form of MetO to Met to maintain intracellular redox balance. However, the relationship between SelR and Aβ was little investigated. Here, we found that SelR can directly interact with Aβ42, and the interaction between SelR and Aβ42 was verified by fluorescence resonance energy transfer (FRET), co-immunoprecipitation (co-IP), and pull-down assays. SelR is closely related to AD, its biological functions in human brain become a research focus. This work implies that SelR makes it capable of modulating Aβ42 aggregation and provides a novel avenue for further study on the mechanism of SelR in AD prevention.
Collapse
Affiliation(s)
- Chao Wang
- Shenzhen Center for Disease Control and Prevention, 518055, Shenzhen, China
| | - Ping Chen
- Department of Biochemical Engineering, Nanyang Institute of Technology, 473004, Nanyang, China
| | - Xiaohong He
- Enshi Center for Disease Control and Prevention, 445000, Enshi, China
| | - Zaisheng Peng
- Enshi Center for Disease Control and Prevention, 445000, Enshi, China
| | - Siqiang Chen
- Enshi Center for Disease Control and Prevention, 445000, Enshi, China
| | - Renli Zhang
- Shenzhen Center for Disease Control and Prevention, 518055, Shenzhen, China.
| | - Jinquan Cheng
- Shenzhen Center for Disease Control and Prevention, 518055, Shenzhen, China.
| | - Qiong Liu
- Department of Marine Biology, Shenzhen Key Laboratory of Marine Biotechnology and Ecology, Shenzhen University, 518060, Shenzhen, China.
| |
Collapse
|
104
|
Dysregulation of intracellular trafficking and endosomal sorting in Alzheimer's disease: controversies and unanswered questions. Biochem J 2017; 473:1977-93. [PMID: 27407168 DOI: 10.1042/bcj20160147] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/18/2016] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of amyloid plaques in the brain consisting of an aggregated form of amyloid β-peptide (Aβ) derived from sequential amyloidogenic processing of the amyloid precursor protein (APP) by membrane-bound proteases β-site APP-cleaving enzyme 1 (BACE1) and γ-secretase. The initial processing of APP by BACE1 is re-gulated by intracellular sorting events of the enzyme, which is a prime target for therapeutic intervention. GWAS (genome-wide sequencing studies) have identified several AD-susceptibility genes that are associated with the regulation of membrane trafficking, and substantial evidence now indicates that AD is likely to arise from defective membrane trafficking in either or both of the secretory and endocytic pathways. Considerable progress has been made in defining the intracellular trafficking pathways of BACE1 and APP and the sorting signals of these membrane proteins that define their itineraries. In this review we highlight recent advances in understanding the regulation of the intracellular sorting of BACE1 and APP, discuss how dysregulation of these trafficking events may lead to enhanced generation of the neurotoxic Aβ products in AD and highlight the unresolved questions in the field.
Collapse
|
105
|
Barykin EP, Mitkevich VA, Kozin SA, Makarov AA. Amyloid β Modification: A Key to the Sporadic Alzheimer's Disease? Front Genet 2017; 8:58. [PMID: 28555154 PMCID: PMC5430028 DOI: 10.3389/fgene.2017.00058] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/27/2017] [Indexed: 11/13/2022] Open
Affiliation(s)
- Evgeny P Barykin
- Engelhardt Institute of Molecular Biology, Russian Academy of SciencesMoscow, Russia
| | - Vladimir A Mitkevich
- Engelhardt Institute of Molecular Biology, Russian Academy of SciencesMoscow, Russia
| | - Sergey A Kozin
- Engelhardt Institute of Molecular Biology, Russian Academy of SciencesMoscow, Russia
| | - Alexander A Makarov
- Engelhardt Institute of Molecular Biology, Russian Academy of SciencesMoscow, Russia
| |
Collapse
|
106
|
McInerney MP, Short JL, Nicolazzo JA. Neurovascular Alterations in Alzheimer's Disease: Transporter Expression Profiles and CNS Drug Access. AAPS JOURNAL 2017; 19:940-956. [PMID: 28462473 DOI: 10.1208/s12248-017-0077-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/15/2017] [Indexed: 01/05/2023]
Abstract
Despite a century of steady and incremental progress toward understanding the underlying biochemical mechanisms, Alzheimer's disease (AD) remains a complicated and enigmatic disease, and greater insight will be necessary before substantive clinical success is realised. Over the last decade in particular, a large body of work has highlighted the cerebral microvasculature as an anatomical region with an increasingly apparent role in the pathogenesis of AD. The causative interplay and temporal cascade that manifest between the brain vasculature and the wider disease progression of AD are not yet fully understood, and further inquiry is required to properly characterise these relationships. The purpose of this review is to highlight the recent advancements in research implicating neurovascular factors in AD, at both the molecular and anatomical levels. We begin with a brief introduction of the biochemical and genetic aspects of AD, before reviewing the essential concepts of the blood-brain barrier (BBB) and the neurovascular unit (NVU). In detail, we then examine the evidence demonstrating involvement of BBB dysfunction in AD pathogenesis, highlighting the importance of neurovascular components in AD. Lastly, we include within this review research that focuses on how altered properties of the BBB in AD impact upon CNS exposure of therapeutic agents and the potential clinical impact that this may have on people with this disease.
Collapse
Affiliation(s)
- Mitchell P McInerney
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - Jennifer L Short
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, 3052, VIC, Australia
| | - Joseph A Nicolazzo
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia.
| |
Collapse
|
107
|
Lin HC, Ho MY, Tsen CM, Huang CC, Wu CC, Huang YJ, Hsiao IL, Chuang CY. From the Cover: Comparative Proteomics Reveals Silver Nanoparticles Alter Fatty Acid Metabolism and Amyloid Beta Clearance for Neuronal Apoptosis in a Triple Cell Coculture Model of the Blood–Brain Barrier. Toxicol Sci 2017; 158:151-163. [DOI: 10.1093/toxsci/kfx079] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
|
108
|
Jang JK, Park KJ, Lee JH, Ko KY, Kang S, Kim IY. Selenoprotein S is required for clearance of C99 through endoplasmic reticulum-associated degradation. Biochem Biophys Res Commun 2017; 486:444-450. [PMID: 28315680 DOI: 10.1016/j.bbrc.2017.03.060] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 03/14/2017] [Indexed: 12/30/2022]
Abstract
Amyloid beta precursor protein (APP) is normally cleaved by α-secretase, but can also be cleaved by β-secretase (BACE1) to produce C99 fragments in the endoplasmic reticulum (ER) membrane. C99 is subsequently cleaved to amyloid β (Aβ), the aggregation of which is known to cause Alzheimer's disease. Therefore, C99 removing is for preventing the disease. Selenoprotein S (SelS) is an ER membrane protein participating in endoplasmic reticulum-associated degradation (ERAD), one of the stages in resolving ER stress of misfolded proteins accumulated in the ER. ERAD has been postulated as one of the processes to degrade C99; however, it remains unclear if the degradation depends on SelS. In this study, we investigated the effect of SelS on C99 degradation. We observed that both SelS and C99 were colocalized in the membrane fraction of mouse neuroblastoma Neuro2a (N2a) cells. While the level of SelS was increased by ER stress, the level of C99 was decreased. However, despite the induction of ER stress, there was no change in the amount of C99 in SelS knock-down cells. The interaction of C99 with p97(VCP), an essential component of the ERAD complex, did not occur in SelS knock-down cells. The ubiquitination of C99 was decreased in SelS knock-down cells. We also found that the extracellular amount of Aβ1-42 was relatively higher in SelS knock-down cells than in control cells. These results suggest that SelS is required for C99 degradation through ERAD, resulting in inhibition of Aβ production.
Collapse
Affiliation(s)
- Jun Ki Jang
- Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 02841, Republic of Korea
| | - Ki Jun Park
- Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 02841, Republic of Korea
| | - Jea Hwang Lee
- Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 02841, Republic of Korea
| | - Kwan Young Ko
- Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 02841, Republic of Korea
| | - Seongman Kang
- Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 02841, Republic of Korea
| | - Ick Young Kim
- Division of Life Sciences, Korea University, 1, 5-Ka, Anam-Dong, Sungbuk-Ku, Seoul 02841, Republic of Korea.
| |
Collapse
|
109
|
Takahashi RH, Nagao T, Gouras GK. Plaque formation and the intraneuronal accumulation of β-amyloid in Alzheimer's disease. Pathol Int 2017; 67:185-193. [PMID: 28261941 DOI: 10.1111/pin.12520] [Citation(s) in RCA: 218] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 02/02/2017] [Indexed: 12/25/2022]
Abstract
Amyloid plaques and neurofibrillary tangles (NFTs) in the brain are the neuropathological hallmarks of Alzheimer's disease (AD). Amyloid plaques are composed of β-amyloid peptides (Aβ), while NFTs contain hyperphosphorylated tau proteins. Patients with familial AD who have mutations in the amyloid precursor protein (APP) gene have either increased production of Aβ or generate more aggregation-prone forms of Aβ. The findings of familial AD mutations in the APP gene suggest that Aβ plays a central role in the pathophysiology of AD. Aβ42, composed of 42 amino acid residues, aggregates readily and is considered to form amyloid plaque. However, the processes of plaque formation are still not well known. It is generally thought that Aβ is secreted into the extracellular space and aggregates to form amyloid plaques. Aβ as extracellular aggregates and amyloid plaques are thought to be toxic to the surrounding neurons. The intraneuronal accumulation of Aβ has more recently been demonstrated and is reported to be involved in synaptic dysfunction, cognitive impairment, and the formation of amyloid plaques in AD. We herein provide an overview of the process of the intraneuronal accumulation of Aβ and plaque formation, and discuss its implications for the pathology, early diagnosis, and therapy of AD.
Collapse
Affiliation(s)
| | - Toshitaka Nagao
- Department of Anatomic Pathology, Tokyo Medical University, Tokyo, Japan
| | - Gunnar K Gouras
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| |
Collapse
|
110
|
Greco S, Zaccagnini G, Fuschi P, Voellenkle C, Carrara M, Sadeghi I, Bearzi C, Maimone B, Castelvecchio S, Stellos K, Gaetano C, Menicanti L, Martelli F. Increased BACE1-AS long noncoding RNA and β-amyloid levels in heart failure. Cardiovasc Res 2017; 113:453-463. [DOI: 10.1093/cvr/cvx013] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 01/25/2017] [Indexed: 01/18/2023] Open
Affiliation(s)
- Simona Greco
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | - Germana Zaccagnini
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | - Paola Fuschi
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | - Christine Voellenkle
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | - Matteo Carrara
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | - Iman Sadeghi
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | - Claudia Bearzi
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council of Italy (CNR), Monterotondo Scalo, Rome, Italy
| | - Biagina Maimone
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| | | | - Konstantinos Stellos
- Laboratory of RNA Metabolism and Vascular Inflammation, Institute of Cardiovascular Regeneration, Centre of Molecular Medicine, Goethe University Frankfurt, Frankfurt/Main, Germany
| | - Carlo Gaetano
- Division of Cardiovascular Epigenetics, Department of Cardiology and Internal Medicine Clinic III, Department of Cardiology, Goethe University, Frankfurt/Main, Germany
| | - Lorenzo Menicanti
- Department of Cardiac Surgery, IRCCS Policlinico San Donato, Milan, Italy
| | - Fabio Martelli
- Molecular Cardiology Laboratory, IRCCS Policlinico San Donato, Via Morandi, 30 20097 San Donato, Milanese, Milan, Italy
| |
Collapse
|
111
|
Tong BCK, Lee CSK, Cheng WH, Lai KO, Foskett JK, Cheung KH. Familial Alzheimer's disease-associated presenilin 1 mutants promote γ-secretase cleavage of STIM1 to impair store-operated Ca2+ entry. Sci Signal 2016; 9:ra89. [PMID: 27601731 DOI: 10.1126/scisignal.aaf1371] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Some forms of familial Alzheimer's disease (FAD) are caused by mutations in presenilins (PSs), catalytic components of a γ-secretase complex that cleaves target proteins, including amyloid precursor protein (APP). Calcium (Ca(2+)) dysregulation in cells with these FAD-causing PS mutants has been attributed to attenuated store-operated Ca(2+) entry [SOCE; also called capacitative Ca(2+) entry (CCE)]. CCE occurs when STIM1 detects decreases in Ca(2+) in the endoplasmic reticulum (ER) and activates ORAI channels to replenish Ca(2+) stores in the ER. We showed that CCE was attenuated by PS1-associated γ-secretase activity. Endogenous PS1 and STIM1 interacted in human neuroblastoma SH-SY5Y cells, patient fibroblasts, and mouse primary cortical neurons. Forms of PS1 with FAD-associated mutations enhanced γ-secretase cleavage of the STIM1 transmembrane domain at a sequence that was similar to the γ-secretase cleavage sequence of APP. Cultured hippocampal neurons expressing mutant PS1 had attenuated CCE that was associated with destabilized dendritic spines, which were rescued by either γ-secretase inhibition or overexpression of STIM1. Our results indicate that γ-secretase activity may physiologically regulate CCE by targeting STIM1 and that restoring STIM1 may be a therapeutic approach in AD.
Collapse
Affiliation(s)
- Benjamin Chun-Kit Tong
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Claire Shuk-Kwan Lee
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Wing-Hei Cheng
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Kwok-On Lai
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China. State Key Laboratory of Brain and Cognitive Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - J Kevin Foskett
- Departments of Physiology and Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - King-Ho Cheung
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China. State Key Laboratory of Brain and Cognitive Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China. HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, China.
| |
Collapse
|
112
|
Bernardo TC, Marques-Aleixo I, Beleza J, Oliveira PJ, Ascensão A, Magalhães J. Physical Exercise and Brain Mitochondrial Fitness: The Possible Role Against Alzheimer's Disease. Brain Pathol 2016; 26:648-63. [PMID: 27328058 PMCID: PMC8029062 DOI: 10.1111/bpa.12403] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 06/15/2016] [Indexed: 12/21/2022] Open
Abstract
Exercise is one of the most effective strategies to maintain a healthy body and mind, with particular beneficial effects of exercise on promoting brain plasticity, increasing cognition and reducing the risk of cognitive decline and dementia in later life. Moreover, the beneficial effects resulting from increased physical activity occur at different levels of cellular organization, mitochondria being preferential target organelles. The relevance of this review article relies on the need to integrate the current knowledge of proposed mechanisms, focus mitochondria, to explain the protective effects of exercise that might underlie neuroplasticity and seeks to synthesize these data in the context of exploring exercise as a feasible intervention to delay cognitive impairment associated with neurodegenerative conditions, particularly Alzheimer disease.
Collapse
Affiliation(s)
- T C Bernardo
- CIAFEL-Research Centre in Physical Activity, , Health and Leisure, Faculty of Sport, University of Porto, Porto, Portugal.
| | - I Marques-Aleixo
- CIAFEL-Research Centre in Physical Activity, , Health and Leisure, Faculty of Sport, University of Porto, Porto, Portugal
| | - J Beleza
- CIAFEL-Research Centre in Physical Activity, , Health and Leisure, Faculty of Sport, University of Porto, Porto, Portugal
| | - P J Oliveira
- CNC-Centre for Neuroscience and Cell Biology, UC-Biotech, Biocant Park, University of Coimbra, Coimbra, Portugal
| | - A Ascensão
- CIAFEL-Research Centre in Physical Activity, , Health and Leisure, Faculty of Sport, University of Porto, Porto, Portugal
| | - J Magalhães
- CIAFEL-Research Centre in Physical Activity, , Health and Leisure, Faculty of Sport, University of Porto, Porto, Portugal
| |
Collapse
|
113
|
Wilkins HM, Swerdlow RH. Amyloid precursor protein processing and bioenergetics. Brain Res Bull 2016; 133:71-79. [PMID: 27545490 DOI: 10.1016/j.brainresbull.2016.08.009] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 08/15/2016] [Accepted: 08/17/2016] [Indexed: 02/08/2023]
Abstract
The processing of amyloid precursor protein (APP) to amyloid beta (Aβ) is of great interest to the Alzheimer's disease (AD) field. Decades of research define how APP is altered to form Aβ, and how Aβ generates oligomers, protofibrils, and fibrils. Numerous signaling pathways and changes in cell physiology are known to influence APP processing. Existing data additionally indicate a relationship exists between mitochondria, bioenergetics, and APP processing. Here, we review data that address whether mitochondrial function and bioenergetics modify APP processing and Aβ production.
Collapse
Affiliation(s)
- Heather M Wilkins
- Department of Neurology University of Kansas Medical Center, Kansas City, KS, USA; University of Kansas Alzheimer's Disease Center, Kansas City, KS, USA
| | - Russell H Swerdlow
- Department of Neurology University of Kansas Medical Center, Kansas City, KS, USA; University of Kansas Alzheimer's Disease Center, Kansas City, KS, USA; Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA; Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS USA.
| |
Collapse
|
114
|
Vella LJ, Hill AF, Cheng L. Focus on Extracellular Vesicles: Exosomes and Their Role in Protein Trafficking and Biomarker Potential in Alzheimer's and Parkinson's Disease. Int J Mol Sci 2016; 17:173. [PMID: 26861304 PMCID: PMC4783907 DOI: 10.3390/ijms17020173] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/21/2015] [Indexed: 12/21/2022] Open
Abstract
Growing evidence indicates that small extracellular vesicles, called exosomes, are prominent mediators of neurodegenerative diseases such as prion, Alzheimer's and Parkinson's disease. Exosomes contain neurodegenerative disease associated proteins such as the prion protein, β-amyloid and α-synuclein. Only demonstrated so far in vivo with prion disease, exosomes are hypothesised to also facilitate the spread of β-amyloid and α-synuclein from their cells of origin to the extracellular environment. In the current review, we will discuss the role of exosomes in Alzheimer's and Parkinson's disease including their possible contribution to disease propagation and pathology and highlight their utility as a diagnostic in neurodegenerative disease.
Collapse
Affiliation(s)
- Laura J Vella
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3010, Australia.
| | - Andrew F Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3083, Australia.
| | - Lesley Cheng
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC 3083, Australia.
| |
Collapse
|
115
|
Heterozygous Chorein Deficiency in Probable Tau-negative Early-onset Alzheimer Disease. Alzheimer Dis Assoc Disord 2016; 30:272-5. [PMID: 26825611 PMCID: PMC5035148 DOI: 10.1097/wad.0000000000000130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
116
|
Singh SK, Srivastav S, Yadav AK, Srikrishna S, Perry G. Overview of Alzheimer's Disease and Some Therapeutic Approaches Targeting Aβ by Using Several Synthetic and Herbal Compounds. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:7361613. [PMID: 27034741 PMCID: PMC4807045 DOI: 10.1155/2016/7361613] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 11/05/2015] [Indexed: 01/10/2023]
Abstract
Alzheimer's disease (AD) is a complex age-related neurodegenerative disease. In this review, we carefully detail amyloid-β metabolism and its role in AD. We also consider the various genetic animal models used to evaluate therapeutics. Finally, we consider the role of synthetic and plant-based compounds in therapeutics.
Collapse
Affiliation(s)
- Sandeep Kumar Singh
- Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, India
| | - Saurabh Srivastav
- Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, India
| | - Amarish Kumar Yadav
- Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, India
| | - Saripella Srikrishna
- Department of Biochemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, India
| | - George Perry
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX 78249, USA
| |
Collapse
|
117
|
Pallebage-Gamarallage M, Takechi R, Lam V, Elahy M, Mamo J. Pharmacological modulation of dietary lipid-induced cerebral capillary dysfunction: Considerations for reducing risk for Alzheimer's disease. Crit Rev Clin Lab Sci 2015; 53:166-83. [PMID: 26678521 DOI: 10.3109/10408363.2015.1115820] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
An increasing body of evidence suggests that cerebrovascular dysfunction and microvessel disease precede the evolution of hallmark pathological features that characterise Alzheimer's disease (AD), consistent with a causal association for onset or progression. Recent studies, principally in genetically unmanipulated animal models, suggest that chronic ingestion of diets enriched in saturated fats and cholesterol may compromise blood-brain barrier (BBB) integrity resulting in inappropriate blood-to-brain extravasation of plasma proteins, including lipid macromolecules that may be enriched in amyloid-β (Aβ). Brain parenchymal retention of blood proteins and lipoprotein bound Aβ is associated with heightened neurovascular inflammation, altered redox homeostasis and nitric oxide (NO) metabolism. Therefore, it is a reasonable proposition that lipid-lowering agents may positively modulate BBB integrity and by extension attenuate risk or progression of AD. In addition to their robust lipid lowering properties, reported beneficial effects of lipid-lowering agents were attributed to their pleiotropic properties via modulation of inflammation, oxidative stress, NO and Aβ metabolism. The review is a contemporary consideration of a complex body of literature intended to synthesise focussed consideration of mechanisms central to regulation of BBB function and integrity. Emphasis is given to dietary fat driven significant epidemiological evidence consistent with heightened risk amongst populations consuming greater amounts of saturated fats and cholesterol. In addition, potential neurovascular benefits associated with the use of hypolipidemic statins, probucol and fenofibrate are also presented in the context of lipid-lowering and pleiotropic properties.
Collapse
Affiliation(s)
- Menuka Pallebage-Gamarallage
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| | - Ryusuke Takechi
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| | - Virginie Lam
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| | - Mina Elahy
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| | - John Mamo
- a Faculty of Health Sciences , School of Public Health Curtin University , Perth , WA , Australia and.,b Curtin Health Innovation Research Institute of Aging and Chronic Disease, Curtin University , Perth , WA , Australia
| |
Collapse
|
118
|
Neuronal-Targeted TFEB Accelerates Lysosomal Degradation of APP, Reducing Aβ Generation and Amyloid Plaque Pathogenesis. J Neurosci 2015; 35:12137-51. [PMID: 26338325 DOI: 10.1523/jneurosci.0705-15.2015] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED In AD, an imbalance between Aβ production and removal drives elevated brain Aβ levels and eventual amyloid plaque deposition. APP undergoes nonamyloidogenic processing via α-cleavage at the plasma membrane, amyloidogenic β- and γ-cleavage within endosomes to generate Aβ, or lysosomal degradation in neurons. Considering multiple reports implicating impaired lysosome function as a driver of increased amyloidogenic processing of APP, we explored the efficacy of targeting transcription factor EB (TFEB), a master regulator of lysosomal pathways, to reduce Aβ levels. CMV promoter-driven TFEB, transduced via stereotactic hippocampal injections of adeno-associated virus particles in APP/PS1 mice, localized primarily to neuronal nuclei and upregulated lysosome biogenesis. This resulted in reduction of APP protein, the α and β C-terminal APP fragments (CTFs), and in the steady-state Aβ levels in the brain interstitial fluid. In aged mice, total Aβ levels and amyloid plaque load were selectively reduced in the TFEB-transduced hippocampi. TFEB transfection in N2a cells stably expressing APP695, stimulated lysosome biogenesis, reduced steady-state levels of APP and α- and β-CTFs, and attenuated Aβ generation by accelerating flux through the endosome-lysosome pathway. Cycloheximide chase assays revealed a shortening of APP half-life with exogenous TFEB expression, which was prevented by concomitant inhibition of lysosomal acidification. These data indicate that TFEB enhances flux through lysosomal degradative pathways to induce APP degradation and reduce Aβ generation. Activation of TFEB in neurons is an effective strategy to attenuate Aβ generation and attenuate amyloid plaque deposition in AD. SIGNIFICANCE STATEMENT A key driver for AD pathogenesis is the net balance between production and clearance of Aβ, the major component of amyloid plaques. Here we demonstrate that lysosomal degradation of holo-APP influences Aβ production by limiting the availability of APP for amyloidogenic processing. Using viral gene transfer of transcription factor EB (TFEB), a master regulator of lysosome biogenesis in neurons of APP/PS1 mice, steady-state levels of APP were reduced, resulting in decreased interstitial fluid Aβ levels and attenuated amyloid deposits. These effects were caused by accelerated lysosomal degradation of endocytosed APP, reflected by reduced APP half-life and steady-state levels in TFEB-expressing cells, with resultant decrease in Aβ production and release. Additional studies are needed to explore the therapeutic potential of this approach.
Collapse
|
119
|
Sun X, Chen WD, Wang YD. β-Amyloid: the key peptide in the pathogenesis of Alzheimer's disease. Front Pharmacol 2015; 6:221. [PMID: 26483691 PMCID: PMC4588032 DOI: 10.3389/fphar.2015.00221] [Citation(s) in RCA: 191] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 09/17/2015] [Indexed: 12/20/2022] Open
Abstract
The amyloid β peptide (Aβ) is a critical initiator that triggers the progression of Alzheimer's Disease (AD) via accumulation and aggregation, of which the process may be caused by Aβ overproduction or perturbation clearance. Aβ is generated from amyloid precursor protein through sequential cleavage of β- and γ-secretases while Aβ removal is dependent on the proteolysis and lysosome degradation system. Here, we overviewed the biogenesis and toxicity of Aβ as well as the regulation of Aβ production and clearance. Moreover, we also summarized the animal models correlated with Aβ that are essential in AD research. In addition, we discussed current immunotherapeutic approaches targeting Aβ to give some clues for exploring the more potentially efficient drugs for treatment of AD.
Collapse
Affiliation(s)
- Xiaojuan Sun
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Medicine, Henan University Kaifeng, China
| | - Wei-Dong Chen
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Medicine, Henan University Kaifeng, China
| | - Yan-Dong Wang
- State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology Beijing, China
| |
Collapse
|
120
|
Ghahghaei A, Shahraki S. Inhibitory Effect of β-Casein on the Amyloid Fibril Formation of Aβ1–40 Associated with Alzheimer’s Disease. Int J Pept Res Ther 2015. [DOI: 10.1007/s10989-015-9482-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
121
|
Molecular dynamics simulation study reveals potential substrate entry path into γ-secretase/presenilin-1. J Struct Biol 2015; 191:120-9. [DOI: 10.1016/j.jsb.2015.07.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 05/29/2015] [Accepted: 07/01/2015] [Indexed: 11/20/2022]
|
122
|
Fang D, Wang Y, Zhang Z, Du H, Yan S, Sun Q, Zhong C, Wu L, Vangavaragu JR, Yan S, Hu G, Guo L, Rabinowitz M, Glaser E, Arancio O, Sosunov AA, McKhann GM, Chen JX, Yan SS. Increased neuronal PreP activity reduces Aβ accumulation, attenuates neuroinflammation and improves mitochondrial and synaptic function in Alzheimer disease's mouse model. Hum Mol Genet 2015; 24:5198-210. [PMID: 26123488 DOI: 10.1093/hmg/ddv241] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 06/22/2015] [Indexed: 12/23/2022] Open
Abstract
Accumulation of amyloid-β (Aβ) in synaptic mitochondria is associated with mitochondrial and synaptic injury. The underlying mechanisms and strategies to eliminate Aβ and rescue mitochondrial and synaptic defects remain elusive. Presequence protease (PreP), a mitochondrial peptidasome, is a novel mitochondrial Aβ degrading enzyme. Here, we demonstrate for the first time that increased expression of active human PreP in cortical neurons attenuates Alzheimer disease's (AD)-like mitochondrial amyloid pathology and synaptic mitochondrial dysfunction, and suppresses mitochondrial oxidative stress. Notably, PreP-overexpressed AD mice show significant reduction in the production of proinflammatory mediators. Accordingly, increased neuronal PreP expression improves learning and memory and synaptic function in vivo AD mice, and alleviates Aβ-mediated reduction of long-term potentiation (LTP). Our results provide in vivo evidence that PreP may play an important role in maintaining mitochondrial integrity and function by clearance and degradation of mitochondrial Aβ along with the improvement in synaptic and behavioral function in AD mouse model. Thus, enhancing PreP activity/expression may be a new therapeutic avenue for treatment of AD.
Collapse
Affiliation(s)
- Du Fang
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Yongfu Wang
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Zhihua Zhang
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA, School of Life Sciences, Beijing Normal University, Beijing 100871, China
| | - Heng Du
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Shiqiang Yan
- Taub Institute for Research on Alzheimer's disease and the Aging Brain, New York, NY 10032, USA
| | - Qinru Sun
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Changjia Zhong
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Long Wu
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Jhansi Rani Vangavaragu
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Shijun Yan
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Gang Hu
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Lan Guo
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA
| | - Molly Rabinowitz
- Taub Institute for Research on Alzheimer's disease and the Aging Brain, New York, NY 10032, USA
| | - Elzbieta Glaser
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Ottavio Arancio
- Taub Institute for Research on Alzheimer's disease and the Aging Brain, New York, NY 10032, USA
| | - Alexander A Sosunov
- Department of Neurosurgery, Physicians & Surgeons College of Columbia University, New York, NY 10032, USA and
| | - Guy M McKhann
- Department of Neurosurgery, Physicians & Surgeons College of Columbia University, New York, NY 10032, USA and
| | - John Xi Chen
- Department of Neurology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Shirley ShiDu Yan
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS 66047, USA,
| |
Collapse
|
123
|
Demeritte T, Viraka Nellore BP, Kanchanapally R, Sinha SS, Pramanik A, Chavva SR, Ray PC. Hybrid Graphene Oxide Based Plasmonic-Magnetic Multifunctional Nanoplatform for Selective Separation and Label-Free Identification of Alzheimer's Disease Biomarkers. ACS APPLIED MATERIALS & INTERFACES 2015; 7:13693-700. [PMID: 26027901 PMCID: PMC4677996 DOI: 10.1021/acsami.5b03619] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Despite intense efforts, Alzheimer's disease (AD) is one of the top public health crisis for society even at 21st century. Since presently there is no cure for AD, early diagnosis of possible AD biomarkers is crucial for the society. Driven by the need, the current manuscript reports the development of magnetic core-plasmonic shell nanoparticle attached hybrid graphene oxide based multifunctional nanoplatform which has the capability for highly selective separation of AD biomarkers from whole blood sample, followed by label-free surface enhanced Raman spectroscopy (SERS) identification in femto gram level. Experimental ELISA data show that antibody-conjugated nanoplatform has the capability to capture more than 98% AD biomarkers from the whole blood sample. Reported result shows that nanoplatform can be used for SERS "fingerprint" identification of β-amyloid and tau protein after magnetic separation even at 100 fg/mL level. Experimental results indicate that very high sensitivity achieved is mainly due to the strong plasmon-coupling which generates huge amplified electromagnetic fields at the "hot spot". Experimental results with nontargeted HSA protein, which is one of the most abundant protein components in cerebrospinal fluid (CSF), show that multifunctional nanoplatform based AD biomarkers separation and identification is highly selective.
Collapse
|
124
|
Qiu T, Liu Q, Chen YX, Zhao YF, Li YM. Aβ42 and Aβ40: similarities and differences. J Pept Sci 2015; 21:522-9. [PMID: 26018760 DOI: 10.1002/psc.2789] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 05/05/2015] [Accepted: 05/06/2015] [Indexed: 01/03/2023]
Abstract
The abnormal accumulation of amyloid-β (Aβ) peptide in the brain is one of the most important hallmarks of Alzheimer's disease. Aβ is an aggregation-prone and toxic polypeptide with 39-43 residues, derived from the amyloid precursor protein proteolysis process. According to the amyloid hypothesis, abnormal accumulation of Aβ in the brain is the primary influence driving Alzheimer's disease pathologies. Among all kinds of Aβ isoforms, Aβ40 and Aβ42 are believed to be the most important ones. Although these two kinds of Aβ differ only in two amino acid residues, recent studies show that they differ significantly in their metabolism, physiological functions, toxicities, and aggregation mechanism. In this review, we mainly summarize the similarities and differences between Aβ42 and Aβ40, recent studies on selective inhibitors as well as probes will also be mentioned.
Collapse
Affiliation(s)
- Tian Qiu
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Qian Liu
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yong-Xiang Chen
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yu-Fen Zhao
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084, China
| | - Yan-Mei Li
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084, China.,Beijing Institute for Brain Disorders, Beijing, 100069, China
| |
Collapse
|
125
|
Justin Thenmozhi A, Dhivyabharathi M, William Raja TR, Manivasagam T, Essa MM. Tannoid principles of Emblica officinalis renovate cognitive deficits and attenuate amyloid pathologies against aluminum chloride induced rat model of Alzheimer's disease. Nutr Neurosci 2015; 19:269-78. [PMID: 25842984 DOI: 10.1179/1476830515y.0000000016] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND/AIMS Emblica officinalis is mentioned as a maharasayana in many Ayurvedic texts and promotes intelligence, memory, freedom from disease, longevity, and strength of the senses. The present study has been designed to explore the memory-enhancing effect of the tannoid principles of E. officinalis (EoT) at the biochemical, anatomical, behavioral, and molecular levels against aluminum chloride (AlCl3) induced Alzheimer's disease (AD) in rats. Aluminum is reported to have an important role in the etiology, pathogenesis, and development of AD. METHODS Male Wistar rats were divided into control, AlCl3 treated, AlCl3 and EoT (50, 100, and 200 mg/kg bw) co-treated, and EoT (200 mg/kg bw) alone treated groups. In control and experimental rats, behavior tests including water maze and open field test, estimation of aluminum, assay of acetylcholinesterase (AChE) activity, and expression of amyloidogenic proteins were performed. RESULTS Intraperitonial injection of AlCl3 (100 mg/kg bw) for 60 days significantly elevated the concentration of aluminum (Al), activity of AChE and protein expressions of amyloid precursor protein, A-beta1-42, beta-, and gamma-secretases as compared to control group in hippocampus and cortex. Co-administration of EoT orally to AlCl3 rats for 60 days significantly revert back the Al concentration, AChE activity, and A-beta synthesis-related molecules in the studied brain regions. The spatial learning, memory, and locomotor impairments observed in AlCl3 treated rats were significantly attenuated by EoT. CONCLUSION Therefore, EoT may be a promising therapy in ameliorating neurotoxicity of aluminum, however further studies are warranted to elucidate the exact mechanism of action of EoT.
Collapse
Affiliation(s)
- Arokiasamy Justin Thenmozhi
- a Department of Biochemistry and Biotechnology, Faculty of Science , Annamalai University , Annamalai Nagar, Tamilnadu 608 002 , India
| | - Mathiyazahan Dhivyabharathi
- a Department of Biochemistry and Biotechnology, Faculty of Science , Annamalai University , Annamalai Nagar, Tamilnadu 608 002 , India
| | - Tharsius Raja William Raja
- a Department of Biochemistry and Biotechnology, Faculty of Science , Annamalai University , Annamalai Nagar, Tamilnadu 608 002 , India
| | - Thamilarasan Manivasagam
- a Department of Biochemistry and Biotechnology, Faculty of Science , Annamalai University , Annamalai Nagar, Tamilnadu 608 002 , India
| | - Musthafa Mohamed Essa
- b Department of Food Science and Nutrition , CAMS, Sultan Qaboos University , Muscat , Oman.,c Ageing and Dementia Research Group, Sultan Qaboos University , Muscat , Oman
| |
Collapse
|
126
|
Jung ES, Hong H, Kim C, Mook-Jung I. Acute ER stress regulates amyloid precursor protein processing through ubiquitin-dependent degradation. Sci Rep 2015; 5:8805. [PMID: 25740315 PMCID: PMC5390087 DOI: 10.1038/srep08805] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 02/05/2015] [Indexed: 12/15/2022] Open
Abstract
Beta-amyloid (Aβ), a major pathological hallmark of Alzheimer's disease (AD), is derived from amyloid precursor protein (APP) through sequential cleavage by β-secretase and γ-secretase enzymes. APP is an integral membrane protein, and plays a key role in the pathogenesis of AD; however, the biological function of APP is still unclear. The present study shows that APP is rapidly degraded by the ubiquitin-proteasome system (UPS) in the CHO cell line in response to endoplasmic reticulum (ER) stress, such as calcium ionophore, A23187, induced calcium influx. Increased levels of intracellular calcium by A23187 induces polyubiquitination of APP, causing its degradation. A23187-induced reduction of APP is prevented by the proteasome inhibitor MG132. Furthermore, an increase in levels of the endoplasmic reticulum-associated degradation (ERAD) marker, E3 ubiquitin ligase HRD1, proteasome activity, and decreased levels of the deubiquitinating enzyme USP25 were observed during ER stress. In addition, we found that APP interacts with USP25. These findings suggest that acute ER stress induces degradation of full-length APP via the ubiquitin-proteasome proteolytic pathway.
Collapse
Affiliation(s)
- Eun Sun Jung
- Department of Biochemistry &Biomedical Science, Seoul National University College of Medicine, Seoul, 110-799, Republic of Korea
| | - HyunSeok Hong
- Medifron DBT, Inc., Gyeongi, 425-838, Republic of Korea
| | - Chaeyoung Kim
- Department of Biochemistry &Biomedical Science, Seoul National University College of Medicine, Seoul, 110-799, Republic of Korea
| | - Inhee Mook-Jung
- Department of Biochemistry &Biomedical Science, Seoul National University College of Medicine, Seoul, 110-799, Republic of Korea
| |
Collapse
|
127
|
Muresan V, Ladescu Muresan Z. Amyloid-β precursor protein: Multiple fragments, numerous transport routes and mechanisms. Exp Cell Res 2015; 334:45-53. [PMID: 25573596 DOI: 10.1016/j.yexcr.2014.12.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 12/26/2014] [Indexed: 02/01/2023]
Abstract
This review provides insight into the intraneuronal transport of the Amyloid-β Precursor Protein (APP), the prototype of an extensively posttranslationally modified and proteolytically cleaved transmembrane protein. Uncovering the intricacies of APP transport proves to be a challenging endeavor of cell biology research, deserving increased priority, since APP is at the core of the pathogenic process in Alzheimer's disease. After being synthesized in the endoplasmic reticulum in the neuronal soma, APP enters the intracellular transport along the secretory, endocytic, and recycling routes. Along these routes, APP undergoes cleavage into defined sets of fragments, which themselves are transported - mostly independently - to distinct sites in neurons, where they exert their functions. We review the currently known routes and mechanisms of transport of full-length APP, and of APP fragments, commenting largely on the experimental challenges posed by studying transport of extensively cleaved proteins. The review emphasizes the interrelationships between the proteolytic and posttranslational modifications, the intracellular transport, and the functions of the APP species. A goal remaining to be addressed in the future is the incorporation of the various views on APP transport into a coherent picture. In this review, the disease context is only marginally addressed; the focus is on the basic biology of APP transport under normal conditions. As shown, the studies of APP transport uncovered numerous mechanisms of transport, some of them conventional, and others, novel, awaiting exploration.
Collapse
Affiliation(s)
- Virgil Muresan
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07101-1709, USA.
| | - Zoia Ladescu Muresan
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07101-1709, USA.
| |
Collapse
|
128
|
Batkulwar KB, Bansode SB, Patil GV, Godbole RK, Kazi RS, Chinnathambi S, Shanmugam D, Kulkarni MJ. Investigation of phosphoproteome in RAGE signaling. Proteomics 2014; 15:245-59. [DOI: 10.1002/pmic.201400169] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 08/14/2014] [Accepted: 10/06/2014] [Indexed: 12/11/2022]
Affiliation(s)
- Kedar B. Batkulwar
- Proteomics Facility; Division of Biochemical Sciences; CSIR-National Chemical Laboratory; Pune India
| | - Sneha B. Bansode
- Proteomics Facility; Division of Biochemical Sciences; CSIR-National Chemical Laboratory; Pune India
| | - Gouri V. Patil
- Proteomics Facility; Division of Biochemical Sciences; CSIR-National Chemical Laboratory; Pune India
| | - Rashmi K. Godbole
- Proteomics Facility; Division of Biochemical Sciences; CSIR-National Chemical Laboratory; Pune India
| | - Rubina S. Kazi
- Proteomics Facility; Division of Biochemical Sciences; CSIR-National Chemical Laboratory; Pune India
| | | | - Dhanasekaran Shanmugam
- Proteomics Facility; Division of Biochemical Sciences; CSIR-National Chemical Laboratory; Pune India
| | - Mahesh J. Kulkarni
- Proteomics Facility; Division of Biochemical Sciences; CSIR-National Chemical Laboratory; Pune India
| |
Collapse
|
129
|
Xu L, Wang C, Chen L, Ren J, Xie J, Jia L. Detection of Aβ-interacting proteins via a novel Aβ-adsorbents that use immobilized regular comb polymer. J Chromatogr B Analyt Technol Biomed Life Sci 2014; 971:94-8. [PMID: 25278441 DOI: 10.1016/j.jchromb.2014.09.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/10/2014] [Accepted: 09/15/2014] [Indexed: 11/25/2022]
Abstract
A detailed study of individual Aβ-interacting proteins has always been a difficult task because Aβ has a wide range of molecular weights and can easily form aggregates. In this study, we established a novel method for isolating Aβ-interacting proteins by utilizing regular comb polymer immobilized on Sepharose CL-4B. To achieve site-directed ligation of Aβ, a cysteine residue was added at the N-terminus of Aβ. Asp and Asp12, which have 2 and 13 carboxyl groups, respectively, were selected as the carriers for the regular comb polymer. Firstly, the N-termini of Asp and Asp12 were immobilized on Sepharose CL-4B. Next, modified Aβ molecules were coupled to the carboxyl groups of Asp and Asp12 using bromoethylamine as a spacer. To obtain homogeneous comb polymer, the efficiency of the reaction was controlled during the synthesis process. Thioflavin T staining indicated that homogeneous Aβ was achieved. The prepared Aβ-adsorbents were used to isolate Aβ-interacting proteins from mice brain extracts. The results showed that the adsorption capacity of the Aβ-adsorbents for proteins in mice brain extracts increased with the ages of the animals. SDS-PAGE analysis of the Aβ-interacting proteins showed that many kinds of brain proteins were selectively adsorbed by the Aβ adsorbents, and the levels of some of these proteins varied with the ages of the animals. The results indicated that Aβ-interacting proteins could be successfully obtained through the use of immobilized comb polymer. Similar method could also be used to isolate other amyloid-interacting proteins.
Collapse
Affiliation(s)
- Li Xu
- College of Life Science and Biotechnology, Dalian University of Technology, Dalian, China
| | - Conggang Wang
- College of Life Science and Biotechnology, Dalian University of Technology, Dalian, China
| | - Linli Chen
- College of Life Science and Biotechnology, Dalian University of Technology, Dalian, China
| | - Jun Ren
- College of Life Science and Biotechnology, Dalian University of Technology, Dalian, China
| | - Jian Xie
- College of Life Science and Biotechnology, Dalian University of Technology, Dalian, China
| | - Lingyun Jia
- College of Life Science and Biotechnology, Dalian University of Technology, Dalian, China.
| |
Collapse
|
130
|
Badshah H, Kim TH, Kim MO. Protective effects of anthocyanins against amyloid beta-induced neurotoxicity in vivo and in vitro. Neurochem Int 2014; 80:51-9. [PMID: 25451757 DOI: 10.1016/j.neuint.2014.10.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 10/08/2014] [Accepted: 10/27/2014] [Indexed: 10/24/2022]
Abstract
Alzheimer's disease (AD) is one of the most common neurodegenerative disorders in recent world, characterized by increased production of amyloid beta in the nervous system with an ultimate effect of apoptotic neurodegeneration. This study was aimed to investigate the neuroprotective effect of black soybean anthocyanins in a neurodegenerative model of amyloid beta 1-42 (Aβ1-42). Aβ1-42 was treated to HT22 cell lines or adult male rats via intra-cerebro-ventricular injection to induce neurotoxicity in these experimental models. Anthocyanins were treated 0.2 mg/kg in case of cell lines or 4 mg/kg intragastrically to adult rats to protect against Aβ-induced neurodegeneration. Assay for cell viability, mitochondrial membrane potential (Ψm), intracellular free Ca(2+) and apoptotic cells (fluoro-jade B and TUNEL) were performed in vitro while western blot analyses were performed to the hippocampal proteins of adult rats. Our results showed that Aβ1-42 treatment reduced cell viability, disturbed the Ψm and Ca(2+) homeostasis in and out of the cell, and increased neuronal apoptosis. Treatment with anthocyanins for 12 hr retained the cell viability, normalized Ψm and Ca(2+) level, and decreased the neuronal cell death. In accordance, anthocyanins reversed Aβ-induced effect on protein expression of mitochondrial apoptotic pathway (Bax, cytochrome C, caspase-9 and caspase-3) and major Alzheimer's markers i.e. Aβ, APP, P-tau and BACE-1. Overall, our results showed that anthocyanins are potential candidates to treat neurodegenerative disorders like AD.
Collapse
Affiliation(s)
- Haroon Badshah
- Department of Biology and Applied Life Science (BK 21 plus), College of Natural Sciences (RINS), Gyeongsang National University, Jinju 660-701, South Korea
| | - Tae Hyun Kim
- Department of Biology and Applied Life Science (BK 21 plus), College of Natural Sciences (RINS), Gyeongsang National University, Jinju 660-701, South Korea
| | - Myeong Ok Kim
- Department of Biology and Applied Life Science (BK 21 plus), College of Natural Sciences (RINS), Gyeongsang National University, Jinju 660-701, South Korea.
| |
Collapse
|
131
|
Enhancing astrocytic lysosome biogenesis facilitates Aβ clearance and attenuates amyloid plaque pathogenesis. J Neurosci 2014; 34:9607-20. [PMID: 25031402 DOI: 10.1523/jneurosci.3788-13.2014] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In sporadic Alzheimer's disease (AD), impaired Aβ removal contributes to elevated extracellular Aβ levels that drive amyloid plaque pathogenesis. Extracellular proteolysis, export across the blood-brain barrier, and cellular uptake facilitate physiologic Aβ clearance. Astrocytes can take up and degrade Aβ, but it remains unclear whether this function is insufficient in AD or can be enhanced to accelerate Aβ removal. Additionally, age-related dysfunction of lysosomes, the major degradative organelles wherein Aβ localizes after uptake, has been implicated in amyloid plaque pathogenesis. We tested the hypothesis that enhancing lysosomal function in astrocytes with transcription factor EB (TFEB), a master regulator of lysosome biogenesis, would promote Aβ uptake and catabolism and attenuate plaque pathogenesis. Exogenous TFEB localized to the nucleus with transcriptional induction of lysosomal biogenesis and function in vitro. This resulted in significantly accelerated uptake of exogenously applied Aβ42, with increased localization to and degradation within lysosomes in C17.2 cells and primary astrocytes, indicating that TFEB is sufficient to coordinately enhance uptake, trafficking, and degradation of Aβ. Stereotactic injection of adeno-associated viral particles carrying TFEB driven by a glial fibrillary acidic protein promoter was used to achieve astrocyte-specific expression in the hippocampus of APP/PS1 transgenic mice. Exogenous TFEB localized to astrocyte nuclei and enhanced lysosome function, resulting in reduced Aβ levels and shortened half-life in the brain interstitial fluid and reduced amyloid plaque load in the hippocampus compared with control virus-injected mice. Therefore, activation of TFEB in astrocytes is an effective strategy to restore adequate Aβ removal and counter amyloid plaque pathogenesis in AD.
Collapse
|
132
|
Plácido AI, Oliveira CR, Moreira PI, Pereira CMF. Enhanced Amyloidogenic Processing of Amyloid Precursor Protein and Cell Death Under Prolonged Endoplasmic Reticulum Stress in Brain Endothelial Cells. Mol Neurobiol 2014; 51:571-90. [DOI: 10.1007/s12035-014-8819-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 07/15/2014] [Indexed: 01/22/2023]
|
133
|
Yan XX, Ma C, Gai WP, Cai H, Luo XG. Can BACE1 inhibition mitigate early axonal pathology in neurological diseases? J Alzheimers Dis 2014; 38:705-18. [PMID: 24081378 DOI: 10.3233/jad-131400] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
β-Secretase-1 (BACE1) is the rate-limiting enzyme for the genesis of amyloid-β (Aβ) peptides, the main constituents of the amyloid plaques in the brains of Alzheimer's disease (AD) patients. BACE1 is being evaluated as an anti-Aβ target for AD therapy. Recent studies indicate that BACE1 elevation is associated with axonal and presynaptic pathology during plaque development. Evidence also points to a biological role for BACE1 in axonal outgrowth and synapse formation during development. Axonal, including presynaptic, pathology exists in AD as well as many other neurological disorders such as Parkinson's disease, epilepsy, stroke, and trauma. In this review, we discuss pharmaceutical BACE1 inhibition as a therapeutic option for axonal pathogenesis, in addition to amyloid pathology. We first introduce the amyloidogenic processing of amyloid-β protein precursor and describe the normal expression pattern of the amyloidogenic proteins in the brain, with an emphasis on BACE1. We then address BACE1 elevation relative to amyloid plaque development, followed by updating recent understanding of a neurotrophic role of BACE1 in axon and synapse development. We further elaborate the occurrence of axonal pathology in some other neurological conditions. Finally, we propose pharmacological inhibition of excessive BACE1 activity as an option to mitigate early axonal pathology occurring in AD and other neurological disorders.
Collapse
Affiliation(s)
- Xiao-Xin Yan
- Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan, China
| | | | | | | | | |
Collapse
|
134
|
Brännström K, Öhman A, Nilsson L, Pihl M, Sandblad L, Olofsson A. The N-terminal Region of Amyloid β Controls the Aggregation Rate and Fibril Stability at Low pH Through a Gain of Function Mechanism. J Am Chem Soc 2014; 136:10956-64. [DOI: 10.1021/ja503535m] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Anders Öhman
- Department
of Pharmacology and Clinical Neuroscience, Umeå University, SE-901 85 Umeå, Sweden
| | | | | | | | | |
Collapse
|
135
|
Wolfe MS. Unlocking truths of γ-secretase in Alzheimer's disease: what is the translational potential? FUTURE NEUROLOGY 2014; 9:419-429. [PMID: 26146489 DOI: 10.2217/fnl.14.35] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Considerable evidence, particularly from genetics, points to the aggregation-prone amyloid β-peptide as a pathogenic entity in Alzheimer's disease. Hence, the proteases that produce this peptide from its precursor protein have been prime targets for the development of potential therapeutics. One of these proteases, γ-secretase, has been a particular focus. Many inhibitors and modulators of this membrane-embedded protease complex have been identified, with some brought into late-stage clinical trials, where they have spectacularly failed. The reasons for these failures will be discussed, along with recent findings on the mechanism of γ-secretase and of Alzheimer-causing mutations that may suggest new strategies for targeting this enzyme.
Collapse
Affiliation(s)
- Michael S Wolfe
- Center for Neurologic Disease, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Tel.: +1 617 525 5511
| |
Collapse
|
136
|
Iulita MF, Allard S, Richter L, Munter LM, Ducatenzeiler A, Weise C, Do Carmo S, Klein WL, Multhaup G, Cuello AC. Intracellular Aβ pathology and early cognitive impairments in a transgenic rat overexpressing human amyloid precursor protein: a multidimensional study. Acta Neuropathol Commun 2014; 2:61. [PMID: 24903713 PMCID: PMC4229908 DOI: 10.1186/2051-5960-2-61] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 05/07/2014] [Indexed: 01/09/2023] Open
Abstract
Numerous studies have implicated the abnormal accumulation of intraneuronal amyloid-β (Aβ) as an important contributor to Alzheimer's disease (AD) pathology, capable of triggering neuroinflammation, tau hyperphosphorylation and cognitive deficits. However, the occurrence and pathological relevance of intracellular Aβ remain a matter of controversial debate. In this study, we have used a multidimensional approach including high-magnification and super-resolution microscopy, cerebro-spinal fluid (CSF) mass spectrometry analysis and ELISA to investigate the Aβ pathology and its associated cognitive impairments, in a novel transgenic rat model overexpressing human APP. Our microscopy studies with quantitative co-localization analysis revealed the presence of intraneuronal Aβ in transgenic rats, with an immunological signal that was clearly distinguished from that of the amyloid precursor protein (APP) and its C-terminal fragments (CTFs). The early intraneuronal pathology was accompanied by a significant elevation of soluble Aβ42 peptides that paralleled the presence and progression of early cognitive deficits, several months prior to amyloid plaque deposition. Aβ38, Aβ39, Aβ40 and Aβ42 peptides were detected in the rat CSF by MALDI-MS analysis even at the plaque-free stages; suggesting that a combination of intracellular and soluble extracellular Aβ may be responsible for impairing cognition at early time points. Taken together, our results demonstrate that the intraneuronal development of AD-like amyloid pathology includes a mixture of molecular species (Aβ, APP and CTFs) of which a considerable component is Aβ; and that the early presence of these species within neurons has deleterious effects in the CNS, even before the development of full-blown AD-like pathology.
Collapse
Affiliation(s)
- M Florencia Iulita
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - Simon Allard
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - Luise Richter
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - Lisa-Marie Munter
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - Adriana Ducatenzeiler
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - Christoph Weise
- />Intitutes of Chemistry and Biochemistry, Freie Universität, Berlin, Germany
| | - Sonia Do Carmo
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - William L Klein
- />Cognitive Neurology and Alzheimer’s Disease Center, Northwestern University Institute for Neuroscience, Chicago, USA
| | - Gerhard Multhaup
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
| | - A Claudio Cuello
- />Department of Pharmacology and Therapeutics, McGill University, 3655 Sir-William-Osler Promenade, Room 1210, Montreal, Quebec Canada
- />Department of Anatomy and Cell Biology, McGill University, Montreal, Canada
- />Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| |
Collapse
|
137
|
Conformational targeting of intracellular Aβ oligomers demonstrates their pathological oligomerization inside the endoplasmic reticulum. Nat Commun 2014; 5:3867. [PMID: 24861166 PMCID: PMC4050278 DOI: 10.1038/ncomms4867] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 04/10/2014] [Indexed: 01/18/2023] Open
Abstract
Aβ oligomers (AβOs) are crucially involved in Alzheimer’s Disease (AD). However, the lack of selective approaches for targeting these polymorphic Aβ assemblies represents a major hurdle in understanding their biosynthesis, traffic and actions in living cells. Here, we established a subcellularly localized conformational-selective interference (CSI) approach, based on the expression of a recombinant antibody fragment against AβOs in the endoplasmic reticulum (ER). By CSI, we can control extra- and intracellular pools of AβOs produced in an AD-relevant cell model, without interfering with the maturation and processing of the Aβ precursor protein. The anti-AβOs intrabody selectively intercepts critical AβO conformers in the ER, modulating their assembly and controlling their actions in pathways of cellular homeostasis and synaptic signalling. Our results demonstrate that intracellular Aβ undergoes pathological oligomerization through critical conformations formed inside the ER. This establishes intracellular AβOs as key targets for AD treatment and presents CSI as a potential targeting strategy. Intracellular Aß oligomers have been linked to Alzheimer’s disease but details about their biosynthesis and function have been hard to obtain due to the lack of selective approaches for targeting them. Here, Meli et al. develop a strategy using recombinant antibodies to target Aß oligomers in the endoplasmic reticulum of cells, and perform mechanistic studies in cellular models of the disease.
Collapse
|
138
|
Durk MR, Han K, Chow ECY, Ahrens R, Henderson JT, Fraser PE, Pang KS. 1α,25-Dihydroxyvitamin D3 reduces cerebral amyloid-β accumulation and improves cognition in mouse models of Alzheimer's disease. J Neurosci 2014; 34:7091-101. [PMID: 24849345 PMCID: PMC6608194 DOI: 10.1523/jneurosci.2711-13.2014] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 04/02/2014] [Accepted: 04/10/2014] [Indexed: 02/05/2023] Open
Abstract
We demonstrate a role of the vitamin D receptor (VDR) in reducing cerebral soluble and insoluble amyloid-β (Aβ) peptides. Short-term treatment of two human amyloid precursor protein-expressing models, Tg2576 and TgCRND8 mice, with 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3], the endogenous active ligand of VDR, resulted in higher brain P-glycoprotein (P-gp) and lower soluble Aβ levels, effects negated with coadministration of elacridar, a P-gp inhibitor. Long-term treatment of TgCRND8 mice with 1,25(OH)2D3 during the period of plaque formation reduced soluble and insoluble plaque-associated Aβ, particularly in the hippocampus in which the VDR is abundant and P-gp induction is greatest after 1,25(OH)2D3 treatment, and this led to improved conditioned fear memory. In mice fed a vitamin D-deficient diet, lower cerebral P-gp expression was observed, but levels were restored on replenishment with VDR ligands. The composite data suggest that the VDR is an important therapeutic target in the prevention and treatment of Alzheimer's disease.
Collapse
Affiliation(s)
- Matthew R Durk
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, Toronto, Ontario, Canada, M5S 3M2
| | - Kyung Han
- Tanz Centre for Research in Neurodegenerative Diseases, Krembil Discovery Tower, Toronto, Ontario, Canada, M5T 2S8
| | - Edwin C Y Chow
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, Toronto, Ontario, Canada, M5S 3M2
| | - Rosemary Ahrens
- Tanz Centre for Research in Neurodegenerative Diseases, Krembil Discovery Tower, Toronto, Ontario, Canada, M5T 2S8
| | - Jeffrey T Henderson
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, Toronto, Ontario, Canada, M5S 3M2
| | - Paul E Fraser
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada, M5S 3H2, and Tanz Centre for Research in Neurodegenerative Diseases, Krembil Discovery Tower, Toronto, Ontario, Canada, M5T 2S8
| | - K Sandy Pang
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, Toronto, Ontario, Canada, M5S 3M2,
| |
Collapse
|
139
|
He XP, Deng Q, Cai L, Wang CZ, Zang Y, Li J, Chen GR, Tian H. Fluorogenic resveratrol-confined graphene oxide for economic and rapid detection of Alzheimer's disease. ACS APPLIED MATERIALS & INTERFACES 2014; 6:5379-5382. [PMID: 24702005 DOI: 10.1021/am5010909] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Developing an effective means for the real-time probing of amyloid β (Aβ) that is closely implicated in Alzheimer's disease (AD) could help better understand and monitor the disease. Here we describe an economic approach based on the simple composition of a natural product, resveratrol (Res), with graphene oxide (GO) for the rapid, fluorogenic recognition of Aβ. The Res@GO composite has proved specific for Aβ over a range of proteins and ions, and could sensitively capture both Aβ monomers and fibers in a physiological buffer solution within only 3 min. The composite can also fluorescently image amyloid deposits in a mouse brain section within 30 min. This new protocol is much cheaper and more timesaving than the conventional immunofluorescence staining technique employed clinically, providing an economic tool for the concise detection of AD.
Collapse
Affiliation(s)
- Xiao-Peng He
- Key Laboratory for Advanced Materials & Institute of Fine Chemicals, East China University of Science and Technology , 130 Meilong Road, Shanghai 200237, P. R. China
| | | | | | | | | | | | | | | |
Collapse
|
140
|
McCord MC, Aizenman E. The role of intracellular zinc release in aging, oxidative stress, and Alzheimer's disease. Front Aging Neurosci 2014; 6:77. [PMID: 24860495 PMCID: PMC4028997 DOI: 10.3389/fnagi.2014.00077] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 04/02/2014] [Indexed: 01/26/2023] Open
Abstract
Brain aging is marked by structural, chemical, and genetic changes leading to cognitive decline and impaired neural functioning. Further, aging itself is also a risk factor for a number of neurodegenerative disorders, most notably Alzheimer’s disease (AD). Many of the pathological changes associated with aging and aging-related disorders have been attributed in part to increased and unregulated production of reactive oxygen species (ROS) in the brain. ROS are produced as a physiological byproduct of various cellular processes, and are normally detoxified by enzymes and antioxidants to help maintain neuronal homeostasis. However, cellular injury can cause excessive ROS production, triggering a state of oxidative stress that can lead to neuronal cell death. ROS and intracellular zinc are intimately related, as ROS production can lead to oxidation of proteins that normally bind the metal, thereby causing the liberation of zinc in cytoplasmic compartments. Similarly, not only can zinc impair mitochondrial function, leading to excess ROS production, but it can also activate a variety of extra-mitochondrial ROS-generating signaling cascades. As such, numerous accounts of oxidative neuronal injury by ROS-producing sources appear to also require zinc. We suggest that zinc deregulation is a common, perhaps ubiquitous component of injurious oxidative processes in neurons. This review summarizes current findings on zinc dyshomeostasis-driven signaling cascades in oxidative stress and age-related neurodegeneration, with a focus on AD, in order to highlight the critical role of the intracellular liberation of the metal during oxidative neuronal injury.
Collapse
Affiliation(s)
- Meghan C McCord
- Department of Neurobiology, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
| | - Elias Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
| |
Collapse
|
141
|
Accumulation of amyloid-like Aβ1-42 in AEL (autophagy-endosomal-lysosomal) vesicles: potential implications for plaque biogenesis. ASN Neuro 2014; 6:AN20130044. [PMID: 24521233 PMCID: PMC4379859 DOI: 10.1042/an20130044] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Abnormal accumulation of Aβ (amyloid β) within AEL (autophagy-endosomal-lysosomal) vesicles is a prominent neuropathological feature of AD (Alzheimer's disease), but the mechanism of accumulation within vesicles is not clear. We express secretory forms of human Aβ1-40 or Aβ1-42 in Drosophila neurons and observe preferential localization of Aβ1-42 within AEL vesicles. In young animals, Aβ1-42 appears to associate with plasma membrane, whereas Aβ1-40 does not, suggesting that recycling endocytosis may underlie its routing to AEL vesicles. Aβ1-40, in contrast, appears to partially localize in extracellular spaces in whole brain and is preferentially secreted by cultured neurons. As animals become older, AEL vesicles become dysfunctional, enlarge and their turnover appears delayed. Genetic inhibition of AEL function results in decreased Aβ1-42 accumulation. In samples from older animals, Aβ1-42 is broadly distributed within neurons, but only the Aβ1-42 within dysfunctional AEL vesicles appears to be in an amyloid-like state. Moreover, the Aβ1-42-containing AEL vesicles share properties with AD-like extracellular plaques. They appear to be able to relocate to extracellular spaces either as a consequence of age-dependent neurodegeneration or a non-neurodegenerative separation from host neurons by plasma membrane infolding. We propose that dysfunctional AEL vesicles may thus be the source of amyloid-like plaque accumulation in Aβ1-42-expressing Drosophila with potential relevance for AD.
Collapse
|
142
|
Baptista FI, Henriques AG, Silva AMS, Wiltfang J, da Cruz e Silva OAB. Flavonoids as therapeutic compounds targeting key proteins involved in Alzheimer's disease. ACS Chem Neurosci 2014; 5:83-92. [PMID: 24328060 DOI: 10.1021/cn400213r] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Alzheimer's disease is characterized by pathological aggregation of protein tau and amyloid-β peptides, both of which are considered to be toxic to neurons. Naturally occurring dietary flavonoids have received considerable attention as alternative candidates for Alzheimer's therapy taking into account their antiamyloidogenic, antioxidative, and anti-inflammatory properties. Experimental evidence supports the hypothesis that certain flavonoids may protect against Alzheimer's disease in part by interfering with the generation and assembly of amyloid-β peptides into neurotoxic oligomeric aggregates and also by reducing tau aggregation. Several mechanisms have been proposed for the ability of flavonoids to prevent the onset or to slow the progression of the disease. Some mechanisms include their interaction with important signaling pathways in the brain like the phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase pathways that regulate prosurvival transcription factors and gene expression. Other processes include the disruption of amyloid-β aggregation and alterations in amyloid precursor protein processing through the inhibition of β-secretase and/or activation of α-secretase, and inhibiting cyclin-dependent kinase-5 and glycogen synthase kinase-3β activation, preventing abnormal tau phosphorylation. The interaction of flavonoids with different signaling pathways put forward their therapeutic potential to prevent the onset and progression of Alzheimer's disease and to promote cognitive performance. Nevertheless, further studies are needed to give additional insight into the specific mechanisms by which flavonoids exert their potential neuroprotective actions in the brain of Alzheimer's disease patients.
Collapse
Affiliation(s)
- Filipa I. Baptista
- Laboratory
of Neurosciences, Centre for Cell Biology, Health Sciences Department
and Biology Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Ana G. Henriques
- Laboratory
of Neurosciences, Centre for Cell Biology, Health Sciences Department
and Biology Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Artur M. S. Silva
- Department of Chemistry & QOPNA, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Jens Wiltfang
- Department
of Psychiatry and Psychotherapy, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Odete A. B. da Cruz e Silva
- Laboratory
of Neurosciences, Centre for Cell Biology, Health Sciences Department
and Biology Department, University of Aveiro, 3810-193 Aveiro, Portugal
| |
Collapse
|
143
|
Pharmacologic inhibition of ROCK2 suppresses amyloid-β production in an Alzheimer's disease mouse model. J Neurosci 2014; 33:19086-98. [PMID: 24305806 DOI: 10.1523/jneurosci.2508-13.2013] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia and has no cure. Genetic, cell biological, and biochemical studies suggest that reducing amyloid-β (Aβ) production may serve as a rational therapeutic avenue to delay or prevent AD progression. Inhibition of RhoA, a Rho GTPase family member, is proposed to curb Aβ production. However, a barrier to this hypothesis has been the limited understanding of how the principal downstream effectors of RhoA, Rho-associated, coiled-coil containing protein kinase (ROCK) 1 and ROCK2, modulate Aβ generation. Here, we report that ROCK1 knockdown increased endogenous human Aβ production, whereas ROCK2 knockdown decreased Aβ levels. Inhibition of ROCK2 kinase activity, using an isoform-selective small molecule (SR3677), suppressed β-site APP cleaving enzyme 1 (BACE1) enzymatic action and diminished production of Aβ in AD mouse brain. Immunofluorescence and confocal microscopy analyses revealed that SR3677 alters BACE1 endocytic distribution and promotes amyloid precursor protein (APP) traffic to lysosomes. Moreover, SR3677 blocked ROCK2 phosphorylation of APP at threonine 654 (T654); in neurons, T654 was critical for APP processing to Aβ. These observations suggest that ROCK2 inhibition reduces Aβ levels through independent mechanisms. Finally, ROCK2 protein levels were increased in asymptomatic AD, mild cognitive impairment, and AD brains, demonstrating that ROCK2 levels change in the earliest stages of AD and remain elevated throughout disease progression. Collectively, these findings highlight ROCK2 as a mechanism-based therapeutic target to combat Aβ production in AD.
Collapse
|
144
|
Jiang S, Li Y, Zhang X, Bu G, Xu H, Zhang YW. Trafficking regulation of proteins in Alzheimer's disease. Mol Neurodegener 2014; 9:6. [PMID: 24410826 PMCID: PMC3891995 DOI: 10.1186/1750-1326-9-6] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 12/15/2013] [Indexed: 12/12/2022] Open
Abstract
The β-amyloid (Aβ) peptide has been postulated to be a key determinant in the pathogenesis of Alzheimer’s disease (AD). Aβ is produced through sequential cleavage of the β-amyloid precursor protein (APP) by β- and γ-secretases. APP and relevant secretases are transmembrane proteins and traffic through the secretory pathway in a highly regulated fashion. Perturbation of their intracellular trafficking may affect dynamic interactions among these proteins, thus altering Aβ generation and accelerating disease pathogenesis. Herein, we review recent progress elucidating the regulation of intracellular trafficking of these essential protein components in AD.
Collapse
Affiliation(s)
| | | | | | | | | | - Yun-wu Zhang
- Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian 361102, China.
| |
Collapse
|
145
|
|
146
|
Stygelbout V, Leroy K, Pouillon V, Ando K, D’Amico E, Jia Y, Luo HR, Duyckaerts C, Erneux C, Schurmans S, Brion JP. Inositol trisphosphate 3-kinase B is increased in human Alzheimer brain and exacerbates mouse Alzheimer pathology. Brain 2014; 137:537-52. [DOI: 10.1093/brain/awt344] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
|
147
|
Lee SL, Thomas P, Fenech M. Extracellular amyloid beta 42 causes necrosis, inhibition of nuclear division, and mitotic disruption under both folate deficient and folate replete conditions as measured by the cytokinesis-block micronucleus cytome assay. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2014; 55:1-14. [PMID: 24038346 DOI: 10.1002/em.21811] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 07/17/2013] [Accepted: 07/19/2013] [Indexed: 06/02/2023]
Abstract
Alzheimer's disease is associated with accumulation of extracellular beta amyloid peptide 42 (Aβ42) which may induce DNA damage and reduce cellular regenerative potential. These effects may be exacerbated under conditions of folate deficiency. The aim of this study was to investigate whether extracellular Aβ42 induces DNA damage and cell death in human peripheral lymphocytes and whether there is an interactive effect between extracellular Aβ42 and folic acid status. Peripheral blood lymphocytes were cultured in medium under conditions of both low and high folate (20 and 200 nM, respectively) and challenged with either Aβ42 or the physiologically normal form Aβ40 (both at 5, 10, 15 µM). Genome stability and cytotoxicity events were investigated using the cytokinesis-block micronucleus cytome (CBMN-cyt) assay. Outcome measures scored included the nuclear division index (NDI), necrosis, apoptosis, binucleated cells with micronuclei (MN), nucleoplasmic bridges (NPB), and nuclear buds (NBUD) and abnormally shaped nuclei (circular, (CIR) and horse-shoe, (HS) that may be indicative of mitotic disruption. Folic acid deficiency significantly reduced NDI (P < 0.001) and increased all the DNA damage biomarkers (MN, NPB, NBUD, HS, CIR), (P < 0.001). In contrast, exposure to Aβ40 had no impact on CBMN cytome biomarkers but Aβ42 significantly reduced NDI (P < 0.01), increased necrosis (P < 0.05) and frequency of cells with circular nuclei (P < 0.01). There was no evidence of an interaction between Aβ42 and folic acid with respect to CBMN cytome biomarkers. Extracellular Aβ42 appears to have cytotoxic and cytostatic effects but its effect on chromosomal instability appears to be small relative to folate deficiency.
Collapse
Affiliation(s)
- Sau Lai Lee
- Commonwealth Scientific and Industrial Research Organisation, (Animal, Food and Health Sciences), Adelaide, South Australia, 5000; Discipline of Physiology, School of Medical Sciences, The University of Adelaide, Adelaide, South Australia, 5005
| | | | | |
Collapse
|
148
|
Bustamante HA, Rivera-Dictter A, Cavieres VA, Muñoz VC, González A, Lin Y, Mardones GA, Burgos PV. Turnover of C99 is controlled by a crosstalk between ERAD and ubiquitin-independent lysosomal degradation in human neuroglioma cells. PLoS One 2013; 8:e83096. [PMID: 24376644 PMCID: PMC3869756 DOI: 10.1371/journal.pone.0083096] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 11/06/2013] [Indexed: 12/28/2022] Open
Abstract
Alzheimer’s disease (AD) is characterized by the buildup of amyloid-β peptides (Aβ) aggregates derived from proteolytic processing of the β-amyloid precursor protein (APP). Amyloidogenic cleavage of APP by β-secretase/BACE1 generates the C-terminal fragment C99/CTFβ that can be subsequently cleaved by γ-secretase to produce Aβ. Growing evidence indicates that high levels of C99/CTFβ are determinant for AD. Although it has been postulated that γ-secretase-independent pathways must control C99/CTFβ levels, the contribution of organelles with degradative functions, such as the endoplasmic reticulum (ER) or lysosomes, is unclear. In this report, we investigated the turnover and amyloidogenic processing of C99/CTFβ in human H4 neuroglioma cells, and found that C99/CTFβ is localized at the Golgi apparatus in contrast to APP, which is mostly found in endosomes. Conditions that localized C99/CTFβ to the ER resulted in its degradation in a proteasome-dependent manner that first required polyubiquitination, consistent with an active role of the ER associated degradation (ERAD) in this process. Furthermore, when proteasomal activity was inhibited C99/CTFβ was degraded in a chloroquine (CQ)-sensitive compartment, implicating lysosomes as alternative sites for its degradation. Our results highlight a crosstalk between degradation pathways within the ER and lysosomes to avoid protein accumulation and toxicity.
Collapse
Affiliation(s)
- Hianara A. Bustamante
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Andrés Rivera-Dictter
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Viviana A. Cavieres
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Vanessa C. Muñoz
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Alexis González
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Yimo Lin
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Gonzalo A. Mardones
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Patricia V. Burgos
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
- * E-mail:
| |
Collapse
|
149
|
Coskuner O, Wise-Scira O. Arginine and disordered amyloid-β peptide structures: molecular level insights into the toxicity in Alzheimer's disease. ACS Chem Neurosci 2013; 4:1549-58. [PMID: 24041422 DOI: 10.1021/cn4001389] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Recent studies present that the single arginine (R) residue in the sequence of Aβ42 adopts abundant β-sheet structure and forms stable salt bridges with various residues. Furthermore, experiments proposed that R stimulates the Aβ assembly and arginine (R) to alanine (A) mutation (R5A) decreases both aggregate formation tendency and the degree of its toxicity. However, the exact roles of R and R5A mutation in the structures of Aβ42 are poorly understood. Extensive molecular dynamics simulations along with thermodynamic calculations present that R5A mutation impacts the structures and free energy landscapes of the aqueous Aβ42 peptide. The β-sheet structure almost disappears in the Ala21-Ala30 region but is more abundant in parts of the central hydrophobic core and C-terminal regions of Aβ42 upon R5A mutation. More abundant α-helix is adopted in parts of the N-terminal and mid-domain regions and less prominent α-helix formation occurs in the central hydrophobic core region of Aβ42 upon R5A mutation. Interestingly, intramolecular interactions between N- and C-terminal or mid-domain regions disappear upon R5A mutation. The structures of Aβ42 are thermodynamically less stable and retain reduced compactness upon R5A mutation. R5A mutant-type structure stability increases with more prominent central hydrophobic core and mid-domain or C-terminal region interactions. Based on our results reported in this work, small organic molecules and antibodies that avoid β-sheet formation in the Ala21-Ala30 region and hinder the intramolecular interactions occurring between the N-terminal and mid-domain or C-terminal regions of Aβ42 may help to reduce Aβ42 toxicity in Alzheimer's disease.
Collapse
Affiliation(s)
- Orkid Coskuner
- Department of Chemistry and ‡Neurosciences
Institute, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
| | - Olivia Wise-Scira
- Department of Chemistry and ‡Neurosciences
Institute, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
| |
Collapse
|
150
|
APP regulates NGF receptor trafficking and NGF-mediated neuronal differentiation and survival. PLoS One 2013; 8:e80571. [PMID: 24224055 PMCID: PMC3815101 DOI: 10.1371/journal.pone.0080571] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 10/14/2013] [Indexed: 11/30/2022] Open
Abstract
β-amyloid precursor protein (APP) is a key factor in Alzheimer's disease (AD) but its physiological function is largely undetermined. APP has been found to regulate retrograde transport of nerve growth factor (NGF), which plays a crucial role in mediating neuronal survival and differentiation. Herein, we reveal the mechanism underlying APP-mediated NGF trafficking, by demonstrating a direct interaction between APP and the two NGF receptors, TrkA and p75NTR. Downregulation of APP leads to reduced cell surface levels of TrkA/p75NTR and increased endocytosis of TrkA/p75NTR and NGF. In addition, APP-deficient cells manifest defects in neurite outgrowth and are more susceptible to Aβ-induced neuronal death at physiological levels of NGF. However, APP-deficient cells show better responses to NGF-stimulated differentiation and survival than control cells. This may be attributed to increased receptor endocytosis and enhanced activation of Akt and MAPK upon NGF stimulation in APP-deficient cells. Together, our results suggest that APP mediates endocytosis of NGF receptors through direct interaction, thereby regulating endocytosis of NGF and NGF-induced downstream signaling pathways for neuronal survival and differentiation.
Collapse
|