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Wang J, Fourriere L, Gleeson PA. Advances in the cell biology of the trafficking and processing of amyloid precursor protein: impact of familial Alzheimer's disease mutations. Biochem J 2024; 481:1297-1325. [PMID: 39302110 DOI: 10.1042/bcj20240056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 09/02/2024] [Accepted: 09/05/2024] [Indexed: 09/22/2024]
Abstract
The production of neurotoxic amyloid-β peptides (Aβ) is central to the initiation and progression of Alzheimer's disease (AD) and involves sequential cleavage of the amyloid precursor protein (APP) by β- and γ-secretases. APP and the secretases are transmembrane proteins and their co-localisation in the same membrane-bound sub-compartment is necessary for APP cleavage. The intracellular trafficking of APP and the β-secretase, BACE1, is critical in regulating APP processing and Aβ production and has been studied in several cellular systems. Here, we summarise the intracellular distribution and transport of APP and its secretases, and the intracellular location for APP cleavage in non-polarised cells and neuronal models. In addition, we review recent advances on the potential impact of familial AD mutations on APP trafficking and processing. This is critical information in understanding the molecular mechanisms of AD progression and in supporting the development of novel strategies for clinical treatment.
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Affiliation(s)
- Jingqi Wang
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Lou Fourriere
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Paul A Gleeson
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
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2
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Volloch V, Rits-Volloch S. Quintessential Synergy: Concurrent Transient Administration of Integrated Stress Response Inhibitors and BACE1 and/or BACE2 Activators as the Optimal Therapeutic Strategy for Alzheimer's Disease. Int J Mol Sci 2024; 25:9913. [PMID: 39337400 PMCID: PMC11432332 DOI: 10.3390/ijms25189913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2024] [Revised: 09/01/2024] [Accepted: 09/03/2024] [Indexed: 09/30/2024] Open
Abstract
The present study analyzes two potential therapeutic approaches for Alzheimer's disease (AD). One is the suppression of the neuronal integrated stress response (ISR). Another is the targeted degradation of intraneuronal amyloid-beta (iAβ) via the activation of BACE1 (Beta-site Aβ-protein-precursor Cleaving Enzyme) and/or BACE2. Both approaches are rational. Both are promising. Both have substantial intrinsic limitations. However, when combined in a carefully orchestrated manner into a composite therapy they display a prototypical synergy and constitute the apparently optimal, potentially most effective therapeutic strategy for AD.
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Affiliation(s)
- Vladimir Volloch
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Sophia Rits-Volloch
- Division of Molecular Medicine, Children's Hospital, Boston, MA 02115, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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Yao Y, Muench M, Alle T, Zhang B, Lucero B, Perez‐Tremble R, McGrosso D, Newman M, Gonzalez DJ, Lee VM, Ballatore C, Brunden KR. A small-molecule microtubule-stabilizing agent safely reduces Aβ plaque and tau pathology in transgenic mouse models of Alzheimer's disease. Alzheimers Dement 2024; 20:4540-4558. [PMID: 38884283 PMCID: PMC11247666 DOI: 10.1002/alz.13875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 04/04/2024] [Accepted: 04/12/2024] [Indexed: 06/18/2024]
Abstract
INTRODUCTION Intraneuronal inclusions composed of tau protein are found in Alzheimer's disease (AD) and other tauopathies. Tau normally binds microtubules (MTs), and its disengagement from MTs and misfolding in AD is thought to result in MT abnormalities. We previously identified triazolopyrimidine-containing MT-stabilizing compounds that provided benefit in AD mouse models and herein describe the characterization and efficacy testing of an optimized candidate, CNDR-51997. METHODS CNDR-51997 underwent pharmacokinetic, pharmacodynamic, safety pharmacology, and mouse tolerability testing. In addition, the compound was examined for efficacy in 5XFAD amyloid beta (Aβ) plaque mice and PS19 tauopathy mice. RESULTS CNDR-51997 significantly reduced Aβ plaques in 5XFAD mice and tau pathology in PS19 mice, with the latter also showing attenuated axonal dystrophy and gliosis. CNDR-51997 was well tolerated at doses that exceeded efficacy doses, with a good safety pharmacology profile. DISCUSSION CNDR-51997 may be a candidate for advancement as a potential therapeutic agent for AD and/or other tauopathies. Highlights There is evidence of microtubule alterations (MT) in Alzheimer's disease (AD) brain and in mouse models of AD pathology. Intermittent dosing with an optimized, brain-penetrant MT-stabilizing small-molecule, CNDR-51997, reduced both Aβ plaque and tau inclusion pathology in established mouse models of AD. CNDR-51997 attenuated axonal dystrophy and gliosis in a tauopathy mouse model, with a strong trend toward reduced hippocampal neuron loss. CNDR-51997 is well tolerated in mice at doses that are meaningfully greater than required for efficacy in AD mouse models, and the compound has a good safety pharmacology profile.
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Affiliation(s)
- Yuemang Yao
- Center for Neurodegenerative Disease ResearchPerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Megan Muench
- Center for Neurodegenerative Disease ResearchPerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Thibault Alle
- Skaggs School of Pharmacy and Pharmaceutical SciencesUniversity of CaliforniaSan DiegoCaliforniaUSA
| | - Bin Zhang
- Center for Neurodegenerative Disease ResearchPerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Bobby Lucero
- Department of Chemistry and BiochemistryUniversity of CaliforniaSan DiegoCaliforniaUSA
| | - Roxanne Perez‐Tremble
- Center for Neurodegenerative Disease ResearchPerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Dominic McGrosso
- Department of PharmacologyUniversity of CaliforniaSan DiegoCaliforniaUSA
| | - Mira Newman
- Center for Neurodegenerative Disease ResearchPerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - David J. Gonzalez
- Skaggs School of Pharmacy and Pharmaceutical SciencesUniversity of CaliforniaSan DiegoCaliforniaUSA
- Department of PharmacologyUniversity of CaliforniaSan DiegoCaliforniaUSA
| | - Virginia M.‐Y. Lee
- Center for Neurodegenerative Disease ResearchPerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Carlo Ballatore
- Skaggs School of Pharmacy and Pharmaceutical SciencesUniversity of CaliforniaSan DiegoCaliforniaUSA
| | - Kurt R. Brunden
- Center for Neurodegenerative Disease ResearchPerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
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4
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Volloch V, Rits-Volloch S. ACH2.0/E, the Consolidated Theory of Conventional and Unconventional Alzheimer's Disease: Origins, Progression, and Therapeutic Strategies. Int J Mol Sci 2024; 25:6036. [PMID: 38892224 PMCID: PMC11172602 DOI: 10.3390/ijms25116036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/19/2024] [Accepted: 05/21/2024] [Indexed: 06/21/2024] Open
Abstract
The centrality of amyloid-beta (Aβ) is an indisputable tenet of Alzheimer's disease (AD). It was initially indicated by the detection (1991) of a mutation within Aβ protein precursor (AβPP) segregating with the disease, which served as a basis for the long-standing Amyloid Cascade Hypothesis (ACH) theory of AD. In the intervening three decades, this notion was affirmed and substantiated by the discovery of numerous AD-causing and AD-protective mutations with all, without an exception, affecting the structure, production, and intraneuronal degradation of Aβ. The ACH postulated that the disease is caused and driven by extracellular Aβ. When it became clear that this is not the case, and the ACH was largely discredited, a new theory of AD, dubbed ACH2.0 to re-emphasize the centrality of Aβ, was formulated. In the ACH2.0, AD is caused by physiologically accumulated intraneuronal Aβ (iAβ) derived from AβPP. Upon reaching the critical threshold, it triggers activation of the autonomous AβPP-independent iAβ generation pathway; its output is retained intraneuronally and drives the AD pathology. The bridge between iAβ derived from AβPP and that generated independently of AβPP is the neuronal integrated stress response (ISR) elicited by the former. The ISR severely suppresses cellular protein synthesis; concurrently, it activates the production of a small subset of proteins, which apparently includes components necessary for operation of the AβPP-independent iAβ generation pathway that are absent under regular circumstances. The above sequence of events defines "conventional" AD, which is both caused and driven by differentially derived iAβ. Since the ISR can be elicited by a multitude of stressors, the logic of the ACH2.0 mandates that another class of AD, referred to as "unconventional", has to occur. Unconventional AD is defined as a disease where a stressor distinct from AβPP-derived iAβ elicits the neuronal ISR. Thus, the essence of both, conventional and unconventional, forms of AD is one and the same, namely autonomous, self-sustainable, AβPP-independent production of iAβ. What distinguishes them is the manner of activation of this pathway, i.e., the mode of causation of the disease. In unconventional AD, processes occurring at locations as distant from and seemingly as unrelated to the brain as, say, the knee can potentially trigger the disease. The present study asserts that these processes include traumatic brain injury (TBI), chronic traumatic encephalopathy, viral and bacterial infections, and a wide array of inflammatory conditions. It considers the pathways which are common to all these occurrences and culminate in the elicitation of the neuronal ISR, analyzes the dynamics of conventional versus unconventional AD, shows how the former can morph into the latter, explains how a single TBI can hasten the occurrence of AD and why it takes multiple TBIs to trigger the disease, and proposes the appropriate therapeutic strategies. It posits that yet another class of unconventional AD may occur where the autonomous AβPP-independent iAβ production pathway is initiated by an ISR-unrelated activator, and consolidates the above notions in a theory of AD, designated ACH2.0/E (for expanded ACH2.0), which incorporates the ACH2.0 as its special case and retains the centrality of iAβ produced independently of AβPP as the driving agent of the disease.
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Affiliation(s)
- Vladimir Volloch
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Sophia Rits-Volloch
- Division of Molecular Medicine, Children’s Hospital, Boston, MA 02115, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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Creekmore BC, Kixmoeller K, Black BE, Lee EB, Chang YW. Ultrastructure of human brain tissue vitrified from autopsy revealed by cryo-ET with cryo-plasma FIB milling. Nat Commun 2024; 15:2660. [PMID: 38531877 PMCID: PMC10965902 DOI: 10.1038/s41467-024-47066-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 03/19/2024] [Indexed: 03/28/2024] Open
Abstract
Ultrastructure of human brain tissue has traditionally been examined using electron microscopy (EM) following fixation, staining, and sectioning, which limit resolution and introduce artifacts. Alternatively, cryo-electron tomography (cryo-ET) allows higher resolution imaging of unfixed cellular samples while preserving architecture, but it requires samples to be vitreous and thin enough for transmission EM. Due to these requirements, cryo-ET has yet to be employed to investigate unfixed, never previously frozen human brain tissue. Here we present a method for generating lamellae in human brain tissue obtained at time of autopsy that can be imaged via cryo-ET. We vitrify the tissue via plunge-freezing and use xenon plasma focused ion beam (FIB) milling to generate lamellae directly on-grid at variable depth inside the tissue. Lamellae generated in Alzheimer's disease brain tissue reveal intact subcellular structures including components of autophagy and potential pathologic tau fibrils. Furthermore, we reveal intact compact myelin and functional cytoplasmic expansions. These images indicate that plasma FIB milling with cryo-ET may be used to elucidate nanoscale structures within the human brain.
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Affiliation(s)
- Benjamin C Creekmore
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Kathryn Kixmoeller
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ben E Black
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute of Structural Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Edward B Lee
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Institute of Structural Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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6
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Armbrust F, Bickenbach K, Altmeppen H, Foggetti A, Winkelmann A, Wulff P, Glatzel M, Pietrzik CU, Becker-Pauly C. A novel mouse model for N-terminal truncated Aβ2-x generation through meprin β overexpression in astrocytes. Cell Mol Life Sci 2024; 81:139. [PMID: 38480559 PMCID: PMC10937767 DOI: 10.1007/s00018-024-05139-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 01/15/2024] [Accepted: 01/18/2024] [Indexed: 03/17/2024]
Abstract
Neurotoxic amyloid-β (Aβ) peptides cause neurodegeneration in Alzheimer's disease (AD) patients' brains. They are released upon proteolytic processing of the amyloid precursor protein (APP) extracellularly at the β-secretase site and intramembranously at the γ-secretase site. Several AD mouse models were developed to conduct respective research in vivo. Most of these classical models overexpress human APP with mutations driving AD-associated pathogenic APP processing. However, the resulting pattern of Aβ species in the mouse brains differs from those observed in AD patients' brains. Particularly mutations proximal to the β-secretase cleavage site (e.g., the so-called Swedish APP (APPswe) fostering Aβ1-x formation) lead to artificial Aβ production, as N-terminally truncated Aβ peptides are hardly present in these mouse brains. Meprin β is an alternative β-secretase upregulated in brains of AD patients and capable of generating N-terminally truncated Aβ2-x peptides. Therefore, we aimed to generate a mouse model for the production of so far underestimated Aβ2-x peptides by conditionally overexpressing meprin β in astrocytes. We chose astrocytes as meprin β was detected in this cell type in close proximity to Aβ plaques in AD patients' brains. The meprin β-overexpressing mice showed elevated amyloidogenic APP processing detected with a newly generated neo-epitope-specific antibody. Furthermore, we observed elevated Aβ production from endogenous APP as well as AD-related behavior changes (hyperlocomotion and deficits in spatial memory). The novel mouse model as well as the established tools and methods will be helpful to further characterize APP cleavage and the impact of different Aβ species in future studies.
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Affiliation(s)
- Fred Armbrust
- Biochemical Institute, Unit for Degradomics of the Protease Web, University of Kiel, Otto-Hahn-Platz 9, 24118, Kiel, Germany.
| | - Kira Bickenbach
- Biochemical Institute, Unit for Degradomics of the Protease Web, University of Kiel, Otto-Hahn-Platz 9, 24118, Kiel, Germany
| | - Hermann Altmeppen
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Angelica Foggetti
- Institute of Physiology, University of Kiel, Kiel, Germany
- Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Haining, 314400, China
- College of Medicine & Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
| | - Anne Winkelmann
- Biochemical Institute, Unit for Degradomics of the Protease Web, University of Kiel, Otto-Hahn-Platz 9, 24118, Kiel, Germany
| | - Peer Wulff
- Institute of Physiology, University of Kiel, Kiel, Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Claus U Pietrzik
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Christoph Becker-Pauly
- Biochemical Institute, Unit for Degradomics of the Protease Web, University of Kiel, Otto-Hahn-Platz 9, 24118, Kiel, Germany.
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7
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Volloch V, Rits-Volloch S. Next Generation Therapeutic Strategy for Treatment and Prevention of Alzheimer's Disease and Aging-Associated Cognitive Decline: Transient, Once-in-a-Lifetime-Only Depletion of Intraneuronal Aβ ( iAβ) by Its Targeted Degradation via Augmentation of Intra- iAβ-Cleaving Activities of BACE1 and/or BACE2. Int J Mol Sci 2023; 24:17586. [PMID: 38139415 PMCID: PMC10744314 DOI: 10.3390/ijms242417586] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
Although the long-standing Amyloid Cascade Hypothesis (ACH) has been largely discredited, its main attribute, the centrality of amyloid-beta (Aβ) in Alzheimer's disease (AD), remains the cornerstone of any potential interpretation of the disease: All known AD-causing mutations, without a single exception, affect, in one way or another, Aβ. The ACH2.0, a recently introduced theory of AD, preserves this attribute but otherwise differs fundamentally from the ACH. It posits that AD is a two-stage disorder where both stages are driven by intraneuronal (rather than extracellular) Aβ (iAβ) albeit of two distinctly different origins. The first asymptomatic stage is the decades-long accumulation of Aβ protein precursor (AβPP)-derived iAβ to the critical threshold. This triggers the activation of the self-sustaining AβPP-independent iAβ production pathway and the commencement of the second, symptomatic AD stage. Importantly, Aβ produced independently of AβPP is retained intraneuronally. It drives the AD pathology and perpetuates the operation of the pathway; continuous cycles of the iAβ-stimulated propagation of its own AβPP-independent production constitute an engine that drives AD, the AD Engine. It appears that the dynamics of AβPP-derived iAβ accumulation is the determining factor that either drives Aging-Associated Cognitive Decline (AACD) and triggers AD or confers the resistance to both. Within the ACH2.0 framework, the ACH-based drugs, designed to lower levels of extracellular Aβ, could be applicable in the prevention of AD and treatment of AACD because they reduce the rate of accumulation of AβPP-derived iAβ. The present study analyzes their utility and concludes that it is severely limited. Indeed, their short-term employment is ineffective, their long-term engagement is highly problematic, their implementation at the symptomatic stages of AD is futile, and their evaluation in conventional clinical trials for the prevention of AD is impractical at best, impossible at worst, and misleading in between. In contrast, the ACH2.0-guided Next Generation Therapeutic Strategy for the treatment and prevention of both AD and AACD, namely the depletion of iAβ via its transient, short-duration, targeted degradation by the novel ACH2.0-based drugs, has none of the shortcomings of the ACH-based drugs. It is potentially highly effective, easily evaluable in clinical trials, and opens up the possibility of once-in-a-lifetime-only therapeutic intervention for prevention and treatment of both conditions. It also identifies two plausible ACH2.0-based drugs: activators of physiologically occurring intra-iAβ-cleaving capabilities of BACE1 and/or BACE2.
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Affiliation(s)
- Vladimir Volloch
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Sophia Rits-Volloch
- Division of Molecular Medicine, Children’s Hospital, Boston, MA 02115, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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8
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Al-Kuraishy HM, Jabir MS, Al-Gareeb AI, Albuhadily AK, Albukhaty S, Sulaiman GM, Batiha GES. Evaluation and targeting of amyloid precursor protein (APP)/amyloid beta (Aβ) axis in amyloidogenic and non-amyloidogenic pathways: A time outside the tunnel. Ageing Res Rev 2023; 92:102119. [PMID: 37931848 DOI: 10.1016/j.arr.2023.102119] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 11/02/2023] [Accepted: 11/03/2023] [Indexed: 11/08/2023]
Abstract
In Alzheimer disease (AD), amyloid precursor protein (APP) and production of amyloid beta (Aβ) which is generated by amyloidogenic pathway is implicated in neurotoxicity and neuronal cell deaths. However, physiological Aβ level is essential to improves neuronal survival, attenuates neuronal apoptosis and has neuroprotective effect. In addition, physiological APP level has neurotrophic effect on the central nervous system (CNS). APP has a critical role in the brain growth and development via activation of long-term potentiation (LTP) and acceleration of neurite outgrowth. Moreover, APP is cleaved by α secretase to form a neuroprotective soluble APP alpha (sAPPα) in non-amyloidogenic pathway. Consequently, this mini-review purposes to highlight the possible beneficial role of APP and Aβ. In addition, this mini-review discussed the modulation of APP processing and Aβ production.
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Affiliation(s)
- Hayder M Al-Kuraishy
- Department of Clinical pharmacology and Medicine, College of Medicine, Mustansiriyah University, Baghdad, Iraq
| | - Majid S Jabir
- Department of Applied science, University of Technology, Iraq.
| | - Ali I Al-Gareeb
- Department of Clinical pharmacology and Medicine, College of Medicine, Mustansiriyah University, Baghdad, Iraq
| | - Ali K Albuhadily
- Department of Clinical pharmacology and Medicine, College of Medicine, Mustansiriyah University, Baghdad, Iraq
| | - Salim Albukhaty
- Department of Chemistry, College of Science, University of Misan, Maysan 62001, Iraq
| | | | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, AlBeheira 22511, Egypt
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9
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Volloch V, Rits-Volloch S. The Amyloid Cascade Hypothesis 2.0 for Alzheimer's Disease and Aging-Associated Cognitive Decline: From Molecular Basis to Effective Therapy. Int J Mol Sci 2023; 24:12246. [PMID: 37569624 PMCID: PMC10419172 DOI: 10.3390/ijms241512246] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/13/2023] Open
Abstract
With the long-standing amyloid cascade hypothesis (ACH) largely discredited, there is an acute need for a new all-encompassing interpretation of Alzheimer's disease (AD). Whereas such a recently proposed theory of AD is designated ACH2.0, its commonality with the ACH is limited to the recognition of the centrality of amyloid-β (Aβ) in the disease, necessitated by the observation that all AD-causing mutations affect, in one way or another, Aβ. Yet, even this narrow commonality is superficial since AD-causing Aβ of the ACH differs distinctly from that specified in the ACH2.0: Whereas in the former, the disease is caused by secreted extracellular Aβ, in the latter, it is triggered by Aβ-protein-precursor (AβPP)-derived intraneuronal Aβ (iAβ) and driven by iAβ generated independently of AβPP. The ACH2.0 envisions AD as a two-stage disorder. The first, asymptomatic stage is a decades-long accumulation of AβPP-derived iAβ, which occurs via internalization of secreted Aβ and through intracellular retention of a fraction of Aβ produced by AβPP proteolysis. When AβPP-derived iAβ reaches critical levels, it activates a self-perpetuating AβPP-independent production of iAβ that drives the second, devastating AD stage, a cascade that includes tau pathology and culminates in neuronal loss. The present study analyzes the dynamics of iAβ accumulation in health and disease and concludes that it is the prime factor driving both AD and aging-associated cognitive decline (AACD). It discusses mechanisms potentially involved in AβPP-independent generation of iAβ, provides mechanistic interpretations for all principal aspects of AD and AACD including the protective effect of the Icelandic AβPP mutation, the early onset of FAD and the sequential manifestation of AD pathology in defined regions of the affected brain, and explains why current mouse AD models are neither adequate nor suitable. It posits that while drugs affecting the accumulation of AβPP-derived iAβ can be effective only protectively for AD, the targeted degradation of iAβ is the best therapeutic strategy for both prevention and effective treatment of AD and AACD. It also proposes potential iAβ-degrading drugs.
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Affiliation(s)
- Vladimir Volloch
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Sophia Rits-Volloch
- Division of Molecular Medicine, Children’s Hospital, Boston, MA 02115, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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10
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Volloch V, Rits-Volloch S. The Amyloid Cascade Hypothesis 2.0: Generalization of the Concept. J Alzheimers Dis Rep 2023; 7:21-35. [PMID: 36777328 PMCID: PMC9912825 DOI: 10.3233/adr-220079] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/09/2022] [Indexed: 12/31/2022] Open
Abstract
Recently, we proposed the Amyloid Cascade Hypothesis 2.0 (ACH2.0), a reformulation of the ACH. In the former, in contrast to the latter, Alzheimer's disease (AD) is driven by intraneuronal amyloid-β (iAβ) and occurs in two stages. In the first, relatively benign stage, Aβ protein precursor (AβPP)-derived iAβ activates, upon reaching a critical threshold, the AβPP-independent iAβ-generating pathway, triggering a devastating second stage resulting in neuronal death. While the ACH2.0 remains aligned with the ACH premise that Aβ is toxic, the toxicity is exerted because of intra- rather than extracellular Aβ. In this framework, a once-in-a-lifetime-only iAβ depletion treatment via transient activation of BACE1 and/or BACE2 (exploiting their Aβ-cleaving activities) or by any means appears to be the best therapeutic strategy for AD. Whereas the notion of differentially derived iAβ being the principal moving force at both AD stages is both plausible and elegant, a possibility remains that the second AD stage is enabled by an AβPP-derived iAβ-activated self-sustaining mechanism producing a yet undefined deleterious "substance X" (sX) which anchors the second AD stage. The present study generalizes the ACH2.0 by incorporating this possibility and shows that, in this scenario, the iAβ depletion therapy may be ineffective at symptomatic AD stages but fully retains its preventive potential for both AD and the aging-associated cognitive decline, which is defined in the ACH2.0 framework as the extended first stage of AD.
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Affiliation(s)
- Vladimir Volloch
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, USA,Correspondence to: Vladimir Volloch, Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, USA. and Sophia Rits-Volloch, Division of Molecular Medicine, Children’s Hospital, Boston, MA, USA. E-mail:
| | - Sophia Rits-Volloch
- Division of Molecular Medicine, Children’s Hospital, Boston, MA, USA,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
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11
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Ulku I, Liebsch F, Akerman SC, Schulz JF, Kulic L, Hock C, Pietrzik C, Di Spiezio A, Thinakaran G, Saftig P, Multhaup G. Mechanisms of amyloid-β34 generation indicate a pivotal role for BACE1 in amyloid homeostasis. Sci Rep 2023; 13:2216. [PMID: 36750595 PMCID: PMC9905473 DOI: 10.1038/s41598-023-28846-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/25/2023] [Indexed: 02/09/2023] Open
Abstract
The beta‑site amyloid precursor protein (APP) cleaving enzyme (BACE1) was discovered due to its "amyloidogenic" activity which contributes to the production of amyloid-beta (Aβ) peptides. However, BACE1 also possesses an "amyloidolytic" activity, whereby it degrades longer Aβ peptides into a non‑toxic Aβ34 intermediate. Here, we examine conditions that shift the equilibrium between BACE1 amyloidogenic and amyloidolytic activities by altering BACE1/APP ratios. In Alzheimer disease brain tissue, we found an association between elevated levels of BACE1 and Aβ34. In mice, the deletion of one BACE1 gene copy reduced BACE1 amyloidolytic activity by ~ 50%. In cells, a stepwise increase of BACE1 but not APP expression promoted amyloidolytic cleavage resulting in dose-dependently increased Aβ34 levels. At the cellular level, a mislocalization of surplus BACE1 caused a reduction in Aβ34 levels. To align the role of γ-secretase in this pathway, we silenced Presenilin (PS) expression and identified PS2-γ-secretase as the main γ-secretase that generates Aβ40 and Aβ42 peptides serving as substrates for BACE1's amyloidolytic cleavage to generate Aβ34.
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Affiliation(s)
- Irem Ulku
- Integrated Program in Neuroscience, McGill University, Montreal, QC, H3G 0B1, Canada
| | - Filip Liebsch
- Integrated Program in Neuroscience, McGill University, Montreal, QC, H3G 0B1, Canada.,Department of Chemistry, Institute of Biochemistry, University of Cologne, 50674, Cologne, Germany
| | - S Can Akerman
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Jana F Schulz
- Institut Für Chemie Und Biochemie, Freie Universität Berlin, 14195, Berlin, Germany.,Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Luka Kulic
- Roche Pharma Research & Early Development, F.Hoffmann-La Roche Ltd., 4070, Basel, Switzerland
| | - Christoph Hock
- Institute for Regenerative Medicine, Un Iversity of Zurich, 8952, Schlieren, Switzerland.,Neurimmune AG, 8952, Schlieren, Switzerland
| | - Claus Pietrzik
- Department Molecular Neurodegeneration, Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University of Mainz, Duesbergweg 6, 55099, Mainz, Germany
| | | | - Gopal Thinakaran
- Department of Molecular Medicine and Byrd Alzheimer's Institute, University of South Florida, Tampa, FL, 33613, USA
| | - Paul Saftig
- Biochemisches Institut, CAU Kiel, Olshausenstr. 40, 24098, Kiel, Germany
| | - Gerhard Multhaup
- Integrated Program in Neuroscience, McGill University, Montreal, QC, H3G 0B1, Canada. .,Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, H3G 1Y6, Canada.
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12
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O’Day DH. Calmodulin and Amyloid Beta as Coregulators of Critical Events during the Onset and Progression of Alzheimer's Disease. Int J Mol Sci 2023; 24:ijms24021393. [PMID: 36674908 PMCID: PMC9863087 DOI: 10.3390/ijms24021393] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/03/2023] [Accepted: 01/05/2023] [Indexed: 01/12/2023] Open
Abstract
Calmodulin (CaM) and a diversity of CaM-binding proteins (CaMBPs) are involved in the onset and progression of Alzheimer's disease (AD). In the amyloidogenic pathway, AβPP1, BACE1 and PSEN-1 are all calcium-dependent CaMBPs as are the risk factor proteins BIN1 and TREM2. Ca2+/CaM-dependent protein kinase II (CaMKII) and calcineurin (CaN) are classic CaMBPs involved in memory and plasticity, two events impacted by AD. Coupled with these events is the production of amyloid beta monomers (Aβ) and oligomers (Aβo). The recent revelations that Aβ and Aβo each bind to both CaM and to a host of Aβ receptors that are also CaMBPs adds a new level of complexity to our understanding of the onset and progression of AD. Multiple Aβ receptors that are proven CaMBPs (e.g., NMDAR, PMCA) are involved in calcium homeostasis an early event in AD and other neurodegenerative diseases. Other CaMBPs that are Aβ receptors are AD risk factors while still others are involved in the amyloidogenic pathway. Aβ binding to receptors not only serves to control CaM's ability to regulate critical proteins, but it is also implicated in Aβ turnover. The complexity of the Aβ/CaM/CaMBP interactions is analyzed using two events: Aβ generation and NMDAR function. The interactions between Aβ, CaM and CaMBPs reveals a new level of complexity to critical events associated with the onset and progression of AD and may help to explain the failure to develop successful therapeutic treatments for the disease.
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Affiliation(s)
- Danton H. O’Day
- Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada;
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
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13
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Monteiro KLC, Dos Santos Alcântara MG, Freire NML, Brandão EM, do Nascimento VL, Dos Santos Viana LM, de Aquino TM, da Silva-Júnior EF. BACE-1 Inhibitors Targeting Alzheimer's Disease. Curr Alzheimer Res 2023; 20:131-148. [PMID: 37309767 DOI: 10.2174/1567205020666230612155953] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 04/27/2023] [Accepted: 05/25/2023] [Indexed: 06/14/2023]
Abstract
The accumulation of amyloid-β (Aβ) is the main event related to Alzheimer's disease (AD) progression. Over the years, several disease-modulating approaches have been reported, but without clinical success. The amyloid cascade hypothesis evolved and proposed essential targets such as tau protein aggregation and modulation of β-secretase (β-site amyloid precursor protein cleaving enzyme 1 - BACE-1) and γ-secretase proteases. BACE-1 cuts the amyloid precursor protein (APP) to release the C99 fragment, giving rise to several Aβ peptide species during the subsequent γ-secretase cleavage. In this way, BACE-1 has emerged as a clinically validated and attractive target in medicinal chemistry, as it plays a crucial role in the rate of Aβ generation. In this review, we report the main results of candidates in clinical trials such as E2609, MK8931, and AZD-3293, in addition to highlighting the pharmacokinetic and pharmacodynamic-related effects of the inhibitors already reported. The current status of developing new peptidomimetic, non-peptidomimetic, naturally occurring, and other class inhibitors are demonstrated, considering their main limitations and lessons learned. The goal is to provide a broad and complete approach to the subject, exploring new chemical classes and perspectives.
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Affiliation(s)
- Kadja Luana Chagas Monteiro
- Research Group on Therapeutic Strategies - GPET, Laboratory of Synthesis and Research in Medicinal Chemistry - LSPMED, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Lourival Melo Mota Avenue, 57072-970, Maceió, Alagoas, Brazil
| | - Marcone Gomes Dos Santos Alcântara
- Research Group on Therapeutic Strategies - GPET, Laboratory of Synthesis and Research in Medicinal Chemistry - LSPMED, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Lourival Melo Mota Avenue, 57072-970, Maceió, Alagoas, Brazil
| | - Nathalia Monteiro Lins Freire
- Research Group on Therapeutic Strategies - GPET, Laboratory of Synthesis and Research in Medicinal Chemistry - LSPMED, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Lourival Melo Mota Avenue, 57072-970, Maceió, Alagoas, Brazil
| | - Esaú Marques Brandão
- Research Group on Therapeutic Strategies - GPET, Laboratory of Synthesis and Research in Medicinal Chemistry - LSPMED, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Lourival Melo Mota Avenue, 57072-970, Maceió, Alagoas, Brazil
| | - Vanessa Lima do Nascimento
- Research Group on Therapeutic Strategies - GPET, Laboratory of Synthesis and Research in Medicinal Chemistry - LSPMED, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Lourival Melo Mota Avenue, 57072-970, Maceió, Alagoas, Brazil
| | - Líbni Maísa Dos Santos Viana
- Research Group on Therapeutic Strategies - GPET, Laboratory of Synthesis and Research in Medicinal Chemistry - LSPMED, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Lourival Melo Mota Avenue, 57072-970, Maceió, Alagoas, Brazil
| | - Thiago Mendonça de Aquino
- Research Group on Therapeutic Strategies - GPET, Laboratory of Synthesis and Research in Medicinal Chemistry - LSPMED, Institute of Chemistry and Biotechnology, Federal University of Alagoas, Lourival Melo Mota Avenue, 57072-970, Maceió, Alagoas, Brazil
| | - Edeildo Ferreira da Silva-Júnior
- Institute of Chemistry and Biotechnology, Federal University of Alagoas, Lourival Melo Mota Avenue, 57072-970, Maceió, Alagoas, Brazil
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14
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Volloch V, Rits-Volloch S. The Amyloid Cascade Hypothesis 2.0: On the Possibility of Once-in-a-Lifetime-Only Treatment for Prevention of Alzheimer’s Disease and for Its Potential Cure at Symptomatic Stages. J Alzheimers Dis Rep 2022; 6:369-399. [PMID: 36072366 PMCID: PMC9397896 DOI: 10.3233/adr-220031] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 06/08/2022] [Indexed: 11/15/2022] Open
Abstract
We posit that Alzheimer’s disease (AD) is driven by amyloid-β (Aβ) generated in the amyloid-β protein precursor (AβPP) independent pathway activated by AβPP-derived Aβ accumulated intraneuronally in a life-long process. This interpretation constitutes the Amyloid Cascade Hypothesis 2.0 (ACH2.0). It defines a tandem intraneuronal-Aβ (iAβ)-anchored cascade occurrence: intraneuronally-accumulated, AβPP-derived iAβ triggers relatively benign cascade that activates the AβPP-independent iAβ-generating pathway, which, in turn, initiates the second, devastating cascade that includes tau pathology and leads to neuronal loss. The entire output of the AβPP-independent iAβ-generating pathway is retained intraneuronally and perpetuates the pathway’s operation. This process constitutes a self-propagating, autonomous engine that drives AD and ultimately kills its host cells. Once activated, the AD Engine is self-reliant and independent from Aβ production in the AβPP proteolytic pathway; operation of the former renders the latter irrelevant to the progression of AD and brands its manipulation for therapeutic purposes, such as BACE (beta-site AβPP-cleaving enzyme) inhibition, as futile. In the proposed AD paradigm, the only valid direct therapeutic strategy is targeting the engine’s components, and the most effective feasible approach appears to be the activation of BACE1 and/or of its homolog BACE2, with the aim of exploiting their Aβ-cleaving activities. Such treatment would collapse the iAβ population and ‘reset’ its levels below those required for the operation of the AD Engine. Any sufficiently selective iAβ-depleting treatment would be equally effective. Remarkably, this approach opens the possibility of a short-duration, once-in-a-lifetime-only or very infrequent, preventive or curative therapy for AD; this therapy would be also effective for prevention and treatment of the ‘common’ pervasive aging-associated cognitive decline. The ACH2.0 clarifies all ACH-unresolved inconsistencies, explains the widespread ‘resilience to AD’ phenomenon, predicts occurrences of a category of AD-afflicted individuals without excessive Aβ plaque load and of a novel type of familial insusceptibility to AD; it also predicts the lifespan-dependent inevitability of AD in humans if untreated preventively. The article details strategy and methodology to generate an adequate AD model and validate the hypothesis; the proposed AD model may also serve as a research and drug development platform.
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Affiliation(s)
- Vladimir Volloch
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA, USA
| | - Sophia Rits-Volloch
- Division of Molecular Medicine, Children’s Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
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15
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Aow J, Huang TR, Thinakaran G, Koo EH. Enhanced cleavage of APP by co-expressed Bace1 alters the distribution of APP and its fragments in neuronal and non-neuronal cells. Mol Neurobiol 2022; 59:3073-3090. [PMID: 35266114 DOI: 10.1007/s12035-022-02733-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/04/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND Alzheimer's disease amyloid-beta peptides (Aβ) are generated via sequential cleavage of the amyloid precursor protein (APP) by β-secretase (Bace1) and γ-secretase. Though the precise subcellular location(s) of Bace1-mediated APP cleavage remains unresolved, current models suggest APP internalization into Bace1-containing endosomes is a critical step. However, direct evidence for this model is lacking, and previous reports that probed the APP/Bace1 interaction (using co-expressed APP and Bace1 differentially labeled with fluorescent protein tags) did not determine if APP fluorescence originated from full-length APP (fl-APP) molecules that had internalized from the cell surface pool. METHODS We adapted the bungarotoxin-ligand (BTX) system to label surface APP and track internalized fluorescent APP/BTX puncta in rodent primary neurons co-expressing fluorescently-tagged Bace1. Subsequently, we employed imaging and biochemical-based approaches to measure N- and C-terminal APP epitope levels in primary neurons, N2a neuroblastoma, and HeLa cell lines. RESULTS We hypothesized that surface-labeled APP/BTX puncta would, upon internalization, colocalize with fluorescently-tagged Bace1. Unexpectedly, we observed a dramatic loss of internalized APP in co-transfected neurons and ~ 80-90% loss of surface-resident fl-APP, which we also observed in HeLa and N2a cells. Loss of surface fl-APP could be reversed by a Bace1 inhibitor, suggesting that enhanced Bace1-mediated APP cleavage was responsible for the altered processing and mis-sorting. Importantly, in a C-terminally-tagged APP construct, the majority of C-terminal fluorescence was preserved in HeLa cells despite the loss of N-terminal APP signal. This phenomenon was not only recapitulated in cultured neurons, but also showed a progressive disappearance of the APP N-terminal tag, reflecting continual cleavage of fl-APP by Bace1 away from the cell body. CONCLUSIONS Our results strongly suggested that in APP/Bace1 co-expression approaches, there was significant early and aberrant Bace1-mediated APP cleavage that perturbed fl-APP trafficking from the secretory pathway onwards, resulting in a substantial loss of surface fl-APP, which in turn led to a marked reduction in APP internalization. In C-terminally-tagged APP constructs, a large fraction of the APP fluorescence signal therefore likely arose from fluorescently-tagged β-C-terminal-fragment (β-CTF) or downstream proteolytic derivatives instead of fl-APP. Thus, care is needed in interpreting results where APP is detected only with a C-terminal tag in the presence of Bace1 co-expression, and previous findings may need to be reinterpreted if it is unclear whether fl-APP is present in normal physiological levels.
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Affiliation(s)
- Jonathan Aow
- Agency for Science, Technology and Research (A*STAR), Genome Institute of Singapore, Singapore, Singapore.
- Department of Medicine, National University of Singapore, Singapore, Singapore.
| | - Tzu-Rung Huang
- Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | - Gopal Thinakaran
- USF Health Byrd Alzheimer's Center and Research Institute and Department of Molecular Medicine, University of South Florida, Tampa, FL, USA
| | - Edward H Koo
- Department of Medicine, National University of Singapore, Singapore, Singapore.
- Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore.
- Department of Neurosciences, University of California San Diego, San Diego, CA, USA.
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16
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Arora S, Sharma D, Layek B, Singh J. A Review of Brain-Targeted Nonviral Gene-Based Therapies for the Treatment of Alzheimer's Disease. Mol Pharm 2021; 18:4237-4255. [PMID: 34705472 DOI: 10.1021/acs.molpharmaceut.1c00611] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Diseases of the central nervous system (CNS) are difficult to treat owing to the complexity of the brain and the presence of a natural blood-brain-barrier (BBB). Alzheimer's disease (AD) is one of the major progressive and currently incurable neurodegenerative disorders of the CNS, which accounts for 60-80% of cases of dementia. The pathophysiology of AD involves the accumulation of amyloid beta (Aβ) plaques and neurofibrillary tangles (NFTs) in the brain. Additionally, synaptic loss and imbalance of neuronal signaling molecules are characterized as important markers of AD. Existing treatments of AD help in the management of its symptoms and aim toward the maintenance of cognitive functions, behavior, and attenuation of gradual memory loss. Over the past decade, nonviral gene therapy has attracted increasing interest due to its various advantages over its viral counterparts. Moreover, advancements in nonviral gene technology have led to their increasing contributions in clinical trials. However, brain-targeted nonviral gene delivery vectors come across various extracellular and intracellular barriers, limiting their ability to transfer the therapeutic gene into the target cells. Chief barriers to nonviral gene therapy have been discussed briefly in this review. We have also highlighted the rapid advancement of several nonviral gene therapies for AD, which are broadly categorized into physical and chemical methods. These methods aim to modulate Aβ, beta-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1), apolipoprotein E, or neurotrophic factors' expression in the CNS. Overall, this review discusses challenges and recent advancements of nonviral gene therapy for AD.
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Affiliation(s)
- Sanjay Arora
- Department of Pharmaceutical Sciences, School of Pharmacy, College of Health Professions, North Dakota State University, Fargo, North Dakota 58105, United States
| | - Divya Sharma
- Department of Pharmaceutical Sciences, School of Pharmacy, College of Health Professions, North Dakota State University, Fargo, North Dakota 58105, United States
| | - Buddhadev Layek
- Department of Pharmaceutical Sciences, School of Pharmacy, College of Health Professions, North Dakota State University, Fargo, North Dakota 58105, United States
| | - Jagdish Singh
- Department of Pharmaceutical Sciences, School of Pharmacy, College of Health Professions, North Dakota State University, Fargo, North Dakota 58105, United States
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17
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Niederschweiberer MA, Schaefer PM, Singh LN, Lausser L, Bhosale D, Hesse R, Calzia E, Kestler HA, Rueck A, Wallace DC, von Einem B, von Arnim CAF. NADH Fluorescence Lifetime Imaging Microscopy Reveals Selective Mitochondrial Dysfunction in Neurons Overexpressing Alzheimer's Disease-Related Proteins. Front Mol Biosci 2021; 8:671274. [PMID: 34195227 PMCID: PMC8236706 DOI: 10.3389/fmolb.2021.671274] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 05/11/2021] [Indexed: 11/13/2022] Open
Abstract
Alzheimer's disease (AD), the most prevalent form of dementia, affects globally more than 30 million people suffering from cognitive deficits and neuropsychiatric symptoms. Substantial evidence for the involvement of mitochondrial dysfunction in the development and/or progression of AD has been shown in addition to the pathological hallmarks amyloid beta (Aβ) and tau. Still, the selective vulnerability and associated selective mitochondrial dysfunction cannot even be resolved to date. We aimed at optically quantifying mitochondrial function on a single-cell level in primary hippocampal neuron models of AD, unraveling differential involvement of cell and mitochondrial populations in amyloid precursor protein (APP)-associated mitochondrial dysfunction. NADH lifetime imaging is a highly sensitive marker-free method with high spatial resolution. However, deciphering cellular bioenergetics of complex cells like primary neurons has still not succeeded yet. To achieve this, we combined highly sensitive NADH lifetime imaging with respiratory inhibitor treatment, allowing characterization of mitochondrial function down to even the subcellular level in primary neurons. Measuring NADH lifetime of the same neuron before and after respiratory treatment reveals the metabolic delta, which can be taken as a surrogate for cellular redox capacity. Correlating NADH lifetime delta with overexpression strength of Aβ-related proteins on the single-cell level, we could verify the important role of intracellular Aβ-mediated mitochondrial toxicity. Subcellularly, we could demonstrate a higher respiration in neuronal somata in general than dendrites, but a similar impairment of somatic and dendritic mitochondria in our AD models. This illustrates the power of NADH lifetime imaging in revealing mitochondrial function on a single and even subcellular level and its potential to shed light into bioenergetic alterations in neuropsychiatric diseases and beyond.
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Affiliation(s)
- Moritz A Niederschweiberer
- Department of Neurology, Ulm University, Ulm, Germany.,Department of Neurology and Experimental Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Patrick M Schaefer
- Department of Neurology, Ulm University, Ulm, Germany.,Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia Research Institute, University of Pennsylvania, Philadelphia, PA, United States
| | - Larry N Singh
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia Research Institute, University of Pennsylvania, Philadelphia, PA, United States
| | - Ludwig Lausser
- Institute of Medical Systems Biology, Ulm University, Ulm, Germany
| | - Devyani Bhosale
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, University of the Sciences, Philadelphia, PA, United States
| | - Raphael Hesse
- Department of Neurology, Ulm University, Ulm, Germany
| | - Enrico Calzia
- University Medical School, Institute of Anesthesiological Pathophysiology and Process Engineering, Ulm, Germany
| | - Hans A Kestler
- Institute of Medical Systems Biology, Ulm University, Ulm, Germany
| | - Angelika Rueck
- Core Facility Confocal and Multiphoton Microscopy, Ulm University, Ulm, Germany
| | - Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia Research Institute, University of Pennsylvania, Philadelphia, PA, United States.,Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | | | - Christine A F von Arnim
- Department of Neurology, Ulm University, Ulm, Germany.,Division of Geriatrics, University Medical Center Göttingen, Göttingen, Germany
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18
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Bhattacharyya R, Black SE, Lotlikar MS, Fenn RH, Jorfi M, Kovacs DM, Tanzi RE. Axonal generation of amyloid-β from palmitoylated APP in mitochondria-associated endoplasmic reticulum membranes. Cell Rep 2021; 35:109134. [PMID: 34010653 PMCID: PMC8287518 DOI: 10.1016/j.celrep.2021.109134] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 02/09/2021] [Accepted: 04/23/2021] [Indexed: 11/14/2022] Open
Abstract
Axonal generation of Alzheimer’s disease (AD)-associated amyloid-β (Aβ) plays a key role in AD neuropathology, but the cellular mechanisms involved in its release have remained elusive. We previously reported that palmitoylated APP (palAPP) partitions to lipid rafts where it serves as a preferred substrate for β-secretase. Mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs) are cholesterol-rich lipid rafts that are upregulated in AD. Here, we show that downregulating MAM assembly by either RNA silencing or pharmacological modulation of the MAM-resident sigma1 receptor (S1R) leads to attenuated β-secretase cleavage of palAPP. Upregulation of MAMs promotes trafficking of palAPP to the cell surface, β-secretase cleavage, and Aβ generation. We develop a microfluidic device and use it to show that MAM levels alter Aβ generation specifically in neuronal processes and axons, but not in cell bodies. These data suggest therapeutic strategies for reducing axonal release of Aβ and attenuating β-amyloid pathology in AD. Bhattacharyya et al. show that the modulation of mitochondrial-associated endoplasmic reticulum membranes (MAMs) via sigma-1 receptor regulates Aβ generation from axons via cell surface trafficking and β-secretase cleavage of MAM-resident palmitoylated APP (palAPP).
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Affiliation(s)
- Raja Bhattacharyya
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Sophia E Black
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Madhura S Lotlikar
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Rebecca H Fenn
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Mehdi Jorfi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Dora M Kovacs
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Rudolph E Tanzi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Henry and Allison McCance Center for Brain Health, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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19
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Zhang J, Long B, Li A, Sun Q, Tian J, Luo T, Ding Z, Gong H, Li X. Whole-Brain Three-Dimensional Profiling Reveals Brain Region Specific Axon Vulnerability in 5xFAD Mouse Model. Front Neuroanat 2020; 14:608177. [PMID: 33324177 PMCID: PMC7726261 DOI: 10.3389/fnana.2020.608177] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 11/03/2020] [Indexed: 11/13/2022] Open
Abstract
Axonopathy is a pathological feature observed in both Alzheimer's disease (AD) patients and animal models. However, identifying the temporal and regional progression of axonopathy during AD development remains elusive. Using the fluorescence micro-optical sectioning tomography system, we acquired whole-brain datasets in the early stage of 5xFAD/Thy1-GFP-M mice. We reported that among GFP labeled axons, GFP-positive axonopathy first formed in the lateral septal nucleus, subiculum, and medial mammillary nucleus. The axonopathy further increased in most brain regions during aging. However, most of the axonopathic varicosities disappeared significantly in the medial mammillary nucleus after 8 weeks old. Continuous three-dimensional datasets showed that axonopathy in the medial mammillary nucleus was mainly located on axons from hippocampal GFP-positive neurons. Using the rabies viral tracer in combination with immunohistochemistry, we found that axons in the medial mammillary nucleus from the subiculum were susceptible to lesions that prior to the occurrence of behavioral disorders. In conclusion, we created an early-stage spatiotemporal map of axonopathy in 5xFAD/Thy1-GFP-M mice and identified specific neural circuits which are vulnerable to axon lesions in an AD mouse model. These findings underline the importance of early interventions for AD, and may contribute to the understanding of its progression and its early symptom treatment.
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Affiliation(s)
- Jianping Zhang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Ben Long
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Anan Li
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China.,HUST-Suzhou Institute for Brainsmatics, JITRI Institute for Brainsmatics, Suzhou, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Qingtao Sun
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China.,HUST-Suzhou Institute for Brainsmatics, JITRI Institute for Brainsmatics, Suzhou, China
| | - Jiaojiao Tian
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Ting Luo
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Zhangheng Ding
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Gong
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China.,HUST-Suzhou Institute for Brainsmatics, JITRI Institute for Brainsmatics, Suzhou, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Xiangning Li
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China.,HUST-Suzhou Institute for Brainsmatics, JITRI Institute for Brainsmatics, Suzhou, China
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20
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Yao Y, Nzou G, Alle T, Tsering W, Maimaiti S, Trojanowski JQ, Lee VMY, Ballatore C, Brunden KR. Correction of microtubule defects within Aβ plaque-associated dystrophic axons results in lowered Aβ release and plaque deposition. Alzheimers Dement 2020; 16:1345-1357. [PMID: 32918367 DOI: 10.1002/alz.12144] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 06/16/2020] [Indexed: 11/09/2022]
Abstract
The hallmark pathologies of the Alzheimer's disease (AD) brain are amyloid beta (Aβ)-containing senile plaques and neurofibrillary tangles formed from the microtubule (MT)-binding tau protein. Tau becomes hyperphosphorylated and disengages from MTs in AD, with evidence of resulting MT structure/function defects. Brain-penetrant MT-stabilizing compounds can normalize MTs and axonal transport in mouse models with tau pathology, thereby reducing neuron loss and decreasing tau pathology. MT dysfunction is also observed in dystrophic axons adjacent to Aβ plaques, resulting in accumulation of amyloid precursor protein (APP) and BACE1 with the potential for enhanced localized Aβ generation. We have examined whether the brain-penetrant MT-stabilizing compound CNDR-51657 might decrease plaque-associated axonal dystrophy and Aβ release in 5XFAD mice that develop an abundance of Aβ plaques. Administration of CNDR-51657 to 1.5-month-old male and female 5XFAD mice for 4 or 7 weeks led to decreased soluble brain Aβ that coincided with reduced APP and BACE1 levels, resulting in decreased formation of insoluble Aβ deposits. These data suggest a vicious cycle whereby initial Aβ plaque formation causes MT disruption in nearby axons, resulting in the local accumulation of APP and BACE1 that facilitates additional Aβ generation and plaque deposition. The ability of a MT-stabilizing compound to attenuate this cycle, and also reduce deficits resulting from reduced tau binding to MTs, suggests that molecules of this type hold promise as potential AD therapeutics.
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Affiliation(s)
- Yuemang Yao
- Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Goodwell Nzou
- Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Thibault Alle
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
| | - Wangchen Tsering
- Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Shaniya Maimaiti
- Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John Q Trojanowski
- Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Virginia M-Y Lee
- Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Carlo Ballatore
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA
| | - Kurt R Brunden
- Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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21
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Lv L, Yang F, Li H, Yuan J. Brain‐targeted co‐delivery of β‐amyloid converting enzyme 1
shRNA
and epigallocatechin‐3‐gallate by multifunctional nanocarriers for Alzheimer's disease treatment. IUBMB Life 2020; 72:1819-1829. [PMID: 32668504 DOI: 10.1002/iub.2330] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/24/2020] [Accepted: 05/24/2020] [Indexed: 12/22/2022]
Affiliation(s)
- Lijie Lv
- Department of Medical and NursingThe First Hospital of Jilin University Changchun China
| | - Fan Yang
- Department of Pediatric SurgeryThe First Hospital of Jilin University Changchun China
| | - He Li
- Department of Pain MedicineThe First Hospital of Jilin University Changchun China
| | - Jiuli Yuan
- Department of Medical and NursingThe First Hospital of Jilin University Changchun China
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22
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Liebsch F, Kulic L, Teunissen C, Shobo A, Ulku I, Engelschalt V, Hancock MA, van der Flier WM, Kunach P, Rosa-Neto P, Scheltens P, Poirier J, Saftig P, Bateman RJ, Breitner J, Hock C, Multhaup G. Aβ34 is a BACE1-derived degradation intermediate associated with amyloid clearance and Alzheimer's disease progression. Nat Commun 2019; 10:2240. [PMID: 31110178 PMCID: PMC6527709 DOI: 10.1038/s41467-019-10152-w] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 04/17/2019] [Indexed: 12/13/2022] Open
Abstract
The beta-site APP cleaving enzyme 1 (BACE1) is known primarily for its initial cleavage of the amyloid precursor protein (APP), which ultimately leads to the generation of Aβ peptides. Here, we provide evidence that altered BACE1 levels and activity impact the degradation of Aβ40 and Aβ42 into a common Aβ34 intermediate. Using human cerebrospinal fluid (CSF) samples from the Amsterdam Dementia Cohort, we show that Aβ34 is elevated in individuals with mild cognitive impairment who later progressed to dementia. Furthermore, Aβ34 levels correlate with the overall Aβ clearance rates in amyloid positive individuals. Using CSF samples from the PREVENT-AD cohort (cognitively normal individuals at risk for Alzheimer’s disease), we further demonstrate that the Aβ34/Aβ42 ratio, representing Aβ degradation and cortical deposition, associates with pre-clinical markers of neurodegeneration. We propose that Aβ34 represents a marker of amyloid clearance and may be helpful for the characterization of Aβ turnover in clinical samples. Aβ34 is generated from degradation of Aβ40 and Aβ42 by β-secretase. Here, the authors show that Aβ34 is a marker for amyloid clearance and is elevated in the CSF of patients that go on to convert from mild cognitive impairment to Alzheimer’s disease, suggesting it may be a useful biomarker.
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Affiliation(s)
- Filip Liebsch
- Department of Pharmacology and Therapeutics and Integrated Program in Neuroscience, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Luka Kulic
- Institute for Regenerative Medicine, University of Zurich, CH-8952, Schlieren, Switzerland
| | - Charlotte Teunissen
- Department of Clinical Chemistry, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, 1081HZ, Amsterdam, The Netherlands
| | - Adeola Shobo
- Department of Pharmacology and Therapeutics and Integrated Program in Neuroscience, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Irem Ulku
- Department of Pharmacology and Therapeutics and Integrated Program in Neuroscience, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Vivienne Engelschalt
- Institut für Chemie und Biochemie, Freie Universität Berlin, 14195, Berlin, Germany
| | - Mark A Hancock
- SPR-MS Facility, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Wiesje M van der Flier
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, 1081HZ, The Netherlands
| | - Peter Kunach
- Translational Neuroimaging Laboratory, The McGill University Research Centre for Studies in Aging, Alzheimer's Disease Research Unit, Douglas Research Institute, McGill University, Montreal, H4H 1R3, QC, Canada
| | - Pedro Rosa-Neto
- Translational Neuroimaging Laboratory, The McGill University Research Centre for Studies in Aging, Alzheimer's Disease Research Unit, Douglas Research Institute, McGill University, Montreal, H4H 1R3, QC, Canada
| | - Philip Scheltens
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, 1081HZ, The Netherlands
| | - Judes Poirier
- Department of Psychiatry, McGill University, Montreal, QC, H4H 1R3, Canada
| | - Paul Saftig
- Biochemisches Institut, Christian-Albrechts-Universität-Kiel, 24118, Kiel, Germany
| | - Randall J Bateman
- Department of Neurology, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - John Breitner
- Department of Psychiatry, McGill University, Montreal, QC, H4H 1R3, Canada
| | - Christoph Hock
- Institute for Regenerative Medicine, University of Zurich, CH-8952, Schlieren, Switzerland.,Neurimmune, CH-8952, Schlieren, Switzerland
| | - Gerhard Multhaup
- Department of Pharmacology and Therapeutics and Integrated Program in Neuroscience, McGill University, Montreal, QC, H3G 1Y6, Canada.
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23
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Wang Z, Xu Q, Cai F, Liu X, Wu Y, Song W. BACE2, a conditional β-secretase, contributes to Alzheimer's disease pathogenesis. JCI Insight 2019; 4:123431. [PMID: 30626751 DOI: 10.1172/jci.insight.123431] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 12/05/2018] [Indexed: 12/21/2022] Open
Abstract
Deposition of amyloid-β protein (Aβ) to form neuritic plaques is the characteristic neuropathology of Alzheimer's disease (AD). Aβ is generated from amyloid precursor protein (APP) by β- and γ-secretase cleavages. BACE1 is the β-secretase and its inhibition induces severe side effects, whereas its homolog BACE2 normally suppresses Aβ by cleaving APP/Aβ at the θ-site (Phe20) within the Aβ domain. Here, we report that BACE2 also processes APP at the β site, and the juxtamembrane helix (JH) of APP inhibits its β-secretase activity, enabling BACE2 to cleave nascent APP and aggravate AD symptoms. JH-disrupting mutations and clusterin binding to JH triggered BACE2-mediated β-cleavage. Both BACE2 and clusterin were elevated in aged mouse brains, and enhanced β-cleavage during aging. Therefore, BACE2 contributes to AD pathogenesis as a conditional β-secretase and could be a preventive and therapeutic target for AD without the side effects of BACE1 inhibition.
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Affiliation(s)
- Zhe Wang
- The National Clinical Research Center for Geriatric Disease, Xuanwu Hospital, Capital Medical University, Beijing, China.,Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, British Columbia, Canada.,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Qin Xu
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Fang Cai
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Xi Liu
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Yili Wu
- Department of Psychiatry, Jining Medical University, Jining, Shandong, China
| | - Weihong Song
- The National Clinical Research Center for Geriatric Disease, Xuanwu Hospital, Capital Medical University, Beijing, China.,Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, British Columbia, Canada.,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
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24
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Zhang M, Wu Q, Yao X, Zhao J, Zhong W, Liu Q, Xiao S. Xanthohumol inhibits tau protein aggregation and protects cells against tau aggregates. Food Funct 2019; 10:7865-7874. [DOI: 10.1039/c9fo02133g] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Xanthohumol is shown to interact with tau protein and inhibit its aggregation.
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Affiliation(s)
- Mohan Zhang
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
| | - Qiuping Wu
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
| | - Xuanbao Yao
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
| | - Junyi Zhao
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
| | - Weicong Zhong
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
| | - Qiong Liu
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
| | - Shifeng Xiao
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
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25
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Scholz D, Chernyshova Y, Ückert AK, Leist M. Reduced Aβ secretion by human neurons under conditions of strongly increased BACE activity. J Neurochem 2018; 147:256-274. [PMID: 29804308 DOI: 10.1111/jnc.14467] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 05/06/2018] [Accepted: 05/23/2018] [Indexed: 12/20/2022]
Abstract
The initial step in the amyloidogenic cascade of amyloid precursor protein (APP) processing is catalyzed by beta-site APP-cleaving enzyme (BACE), and this protease has increased activities in affected areas of Alzheimer's disease brains. We hypothesized that altered APP processing, because of augmented BACE activity, would affect the actions of direct and indirect BACE inhibitors. We therefore compared post-mitotic human neurons (LUHMES) with their BACE-overexpressing counterparts (BLUHMES). Although β-cleavage of APP was strongly increased in BLUHMES, they produced less full-length and truncated amyloid beta (Aβ) than LUHMES. Moreover, low concentrations of BACE inhibitors decreased cellular BACE activity as expected, but increased Aβ1-40 levels. Several other approaches to modulate BACE activity led to a similar, apparently paradoxical, behavior. For instance, reduction in intracellular acidification by bepridil increased Aβ production in parallel with decreased BACE activity. In contrast to BLUHMES, the respective control cells (LUHMES or BLUHMES with catalytically inactive BACE) showed conventional pharmacological responses. Other non-canonical neurochemical responses (so-called 'rebound effects') are well-documented for the Aβ pathway, especially for γ-secretase: a partial block of its activity leads to an increased Aβ secretion by some cell types. We therefore compared LUHMES and BLUHMES regarding rebound effects of γ-secretase inhibitors and found an Aβ rise in LUHMES but not in BLUHMES. Thus, different cellular factors are responsible for the γ-secretase- versus BACE-related Aβ rebound. We conclude that increased BACE activity, possibly accompanied by an altered cellular localization pattern, can dramatically influence Aβ generation in human neurons and affect pharmacological responses to secretase inhibitors. OPEN PRACTICES: Open Science: This manuscript was awarded with the Open Materials Badge. For more information see: https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Diana Scholz
- Chair for in vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - Yana Chernyshova
- Chair for in vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - Anna-Katharina Ückert
- Chair for in vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
| | - Marcel Leist
- Chair for in vitro Toxicology and Biomedicine, University of Konstanz, Konstanz, Germany
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26
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Sharoar MG, Yan R. Effects of altered RTN3 expression on BACE1 activity and Alzheimer's neuritic plaques. Rev Neurosci 2018; 28:145-154. [PMID: 27883331 DOI: 10.1515/revneuro-2016-0054] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 09/20/2016] [Indexed: 12/15/2022]
Abstract
Reticulon 3 (RTN3), which is a member of the reticulon family of proteins, has a biochemical function of shaping tubular endoplasmic reticulum. RTN3 has also been found to interact with β-site amyloid precursor protein cleaving enzyme 1 (BACE1), which initiates the generation of β-amyloid peptides (Aβ) from amyloid precursor protein. Aβ is the major proteinaceous component in neuritic plaques, which constitute one of the major pathological features in brains of Alzheimer's disease (AD) patients. Mice deficient in or overexpressing RTN3 have altered amyloid deposition through effects on BACE1 expression and activity. In this review, we will summarize the current findings concerning the role of RTN3 in AD pathogenesis and demonstrate that RTN3 protein levels act as age-dependent modulators of BACE1 activity and Aβ deposition during the pathogenic progression of AD.
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27
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Lack of BACE1 S-palmitoylation reduces amyloid burden and mitigates memory deficits in transgenic mouse models of Alzheimer's disease. Proc Natl Acad Sci U S A 2017; 114:E9665-E9674. [PMID: 29078331 DOI: 10.1073/pnas.1708568114] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative disorder characterized by pathological brain lesions and a decline in cognitive function. β-Amyloid peptides (Aβ), derived from proteolytic processing of amyloid precursor protein (APP), play a central role in AD pathogenesis. β-Site APP cleaving enzyme 1 (BACE1), the transmembrane aspartyl protease which initiates Aβ production, is axonally transported in neurons and accumulates in dystrophic neurites near cerebral amyloid deposits in AD. BACE1 is modified by S-palmitoylation at four juxtamembrane cysteine residues. S-palmitoylation is a dynamic posttranslational modification that is important for trafficking and function of several synaptic proteins. Here, we investigated the in vivo significance of BACE1 S-palmitoylation through the analysis of knock-in mice with cysteine-to-alanine substitution at the palmitoylated residues (4CA mice). BACE1 expression, as well as processing of APP and other neuronal substrates, was unaltered in 4CA mice despite the lack of BACE1 S-palmitoylation and reduced lipid raft association. Whereas steady-state Aβ levels were similar, synaptic activity-induced endogenous Aβ production was not observed in 4CA mice. Furthermore, we report a significant reduction of cerebral amyloid burden and BACE1 accumulation in dystrophic neurites in the absence of BACE1 S-palmitoylation in mouse models of AD amyloidosis. Studies in cultured neurons suggest that S-palmitoylation is required for dendritic spine localization and axonal targeting of BACE1. Finally, the lack of BACE1 S-palmitoylation mitigates cognitive deficits in 5XFAD mice. Using transgenic mouse models, these results demonstrate that intrinsic posttranslational S-palmitoylation of BACE1 has a significant impact on amyloid pathogenesis and the consequent cognitive decline.
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28
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BACE1 Function and Inhibition: Implications of Intervention in the Amyloid Pathway of Alzheimer's Disease Pathology. Molecules 2017; 22:molecules22101723. [PMID: 29027981 PMCID: PMC6151801 DOI: 10.3390/molecules22101723] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/09/2017] [Accepted: 10/10/2017] [Indexed: 01/18/2023] Open
Abstract
Alzheimer's disease (AD) is a fatal progressive neurodegenerative disorder characterized by increasing loss in memory, cognition, and function of daily living. Among the many pathologic events observed in the progression of AD, changes in amyloid β peptide (Aβ) metabolism proceed fastest, and precede clinical symptoms. BACE1 (β-secretase 1) catalyzes the initial cleavage of the amyloid precursor protein to generate Aβ. Therefore inhibition of BACE1 activity could block one of the earliest pathologic events in AD. However, therapeutic BACE1 inhibition to block Aβ production may need to be balanced with possible effects that might result from diminished physiologic functions BACE1, in particular processing of substrates involved in neuronal function of the brain and periphery. Potentials for beneficial or consequential effects resulting from pharmacologic inhibition of BACE1 are reviewed in context of ongoing clinical trials testing the effect of BACE1 candidate inhibitor drugs in AD populations.
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29
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Chen GF, Xu TH, Yan Y, Zhou YR, Jiang Y, Melcher K, Xu HE. Amyloid beta: structure, biology and structure-based therapeutic development. Acta Pharmacol Sin 2017; 38:1205-1235. [PMID: 28713158 PMCID: PMC5589967 DOI: 10.1038/aps.2017.28] [Citation(s) in RCA: 1001] [Impact Index Per Article: 143.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 03/02/2017] [Indexed: 12/12/2022] Open
Abstract
Amyloid beta peptide (Aβ) is produced through the proteolytic processing of a transmembrane protein, amyloid precursor protein (APP), by β- and γ-secretases. Aβ accumulation in the brain is proposed to be an early toxic event in the pathogenesis of Alzheimer's disease, which is the most common form of dementia associated with plaques and tangles in the brain. Currently, it is unclear what the physiological and pathological forms of Aβ are and by what mechanism Aβ causes dementia. Moreover, there are no efficient drugs to stop or reverse the progression of Alzheimer's disease. In this paper, we review the structures, biological functions, and neurotoxicity role of Aβ. We also discuss the potential receptors that interact with Aβ and mediate Aβ intake, clearance, and metabolism. Additionally, we summarize the therapeutic developments and recent advances of different strategies for treating Alzheimer's disease. Finally, we will report on the progress in searching for novel, potentially effective agents as well as selected promising strategies for the treatment of Alzheimer's disease. These prospects include agents acting on Aβ, its receptors and tau protein, such as small molecules, vaccines and antibodies against Aβ; inhibitors or modulators of β- and γ-secretase; Aβ-degrading proteases; tau protein inhibitors and vaccines; amyloid dyes and microRNAs.
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Affiliation(s)
- Guo-Fang Chen
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Ting-Hai Xu
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yan Yan
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yu-Ren Zhou
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yi Jiang
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Karsten Melcher
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - H Eric Xu
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, MI 49503, USA
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30
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Schaefer PM, von Einem B, Walther P, Calzia E, von Arnim CAF. Metabolic Characterization of Intact Cells Reveals Intracellular Amyloid Beta but Not Its Precursor Protein to Reduce Mitochondrial Respiration. PLoS One 2016; 11:e0168157. [PMID: 28005987 PMCID: PMC5178995 DOI: 10.1371/journal.pone.0168157] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 11/24/2016] [Indexed: 12/17/2022] Open
Abstract
One hallmark of Alzheimer´s disease are senile plaques consisting of amyloid beta (Aβ), which derives from the processing of the amyloid precursor protein (APP). Mitochondrial dysfunction has been linked to the pathogenesis of Alzheimer´s disease and both Aβ and APP have been reported to affect mitochondrial function in isolated systems. However, in intact cells, considering a physiological localization of APP and Aβ, it is pending what triggers the mitochondrial defect. Thus, the aim of this study was to dissect the impact of APP versus Aβ in inducing mitochondrial alterations with respect to their subcellular localization. We performed an overexpression of APP or beta-site amyloid precursor protein cleaving enzyme 1 (BACE1), increasing APP and Aβ levels or Aβ alone, respectively. Conducting a comprehensive metabolic characterization we demonstrate that only APP overexpression reduced mitochondrial respiration, despite lower extracellular Aβ levels compared to BACE overexpression. Surprisingly, this could be rescued by a gamma secretase inhibitor, oppositionally indicating an Aβ-mediated mitochondrial toxicity. Analyzing Aβ localization revealed that intracellular levels of Aβ and an increased spatial association of APP/Aβ with mitochondria are associated with reduced mitochondrial respiration. Thus, our data provide marked evidence for a prominent role of intracellular Aβ accumulation in Alzheimer´s disease associated mitochondrial dysfunction. Thereby it highlights the importance of the localization of APP processing and intracellular transport as a decisive factor for mitochondrial function, linking two prominent hallmarks of neurodegenerative diseases.
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Affiliation(s)
| | | | - Paul Walther
- Central Facility for Electron Microscopy, Ulm University, Ulm, Germany
| | - Enrico Calzia
- Institut für Anästhesiologische Pathophysiologie und Verfahrensentwicklung, Universitätsklinikum Ulm, Ulm, Germany
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31
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Hung COY, Coleman MP. KIF1A mediates axonal transport of BACE1 and identification of independently moving cargoes in living SCG neurons. Traffic 2016; 17:1155-1167. [PMID: 27484852 PMCID: PMC5132087 DOI: 10.1111/tra.12428] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 07/27/2016] [Accepted: 07/29/2016] [Indexed: 12/17/2022]
Abstract
Neurons rely heavily on axonal transport to deliver materials from the sites of synthesis to the axon terminals over distances that can be many centimetres long. KIF1A is the neuron-specific kinesin with the fastest reported anterograde motor activity. Previous studies have shown that KIF1A transports a subset of synaptic proteins, neurofilaments and dense-core vesicles. Using two-colour live imaging, we showed that beta-secretase 1 (BACE1)-mCherry moves together with KIF1A-GFP in both the anterograde and retrograde directions in superior cervical ganglions (SCG) neurons. We confirmed that KIF1A is functionally required for BACE1 transport by using KIF1A siRNA and a KIF1A mutant construct (KIF1A-T312M) to impair its motor activity. We further identified several cargoes that have little or no co-migration with KIF1A-GFP and also move independently from BACE1-mCherry. Together, these findings support a primary role for KIF1A in the anterograde transport of BACE1 and suggest that axonally transported cargoes are sorted into different classes of carrier vesicles in the cell body and are transported by cargo-specific motor proteins through the axon.
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Affiliation(s)
- Christy O Y Hung
- Department of Signalling Programme, Babraham Institute, Cambridge, UK
| | - Michael P Coleman
- Department of Signalling Programme, Babraham Institute, Cambridge, UK.
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK.
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32
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Kimura A, Hata S, Suzuki T. Alternative Selection of β-Site APP-Cleaving Enzyme 1 (BACE1) Cleavage Sites in Amyloid β-Protein Precursor (APP) Harboring Protective and Pathogenic Mutations within the Aβ Sequence. J Biol Chem 2016; 291:24041-24053. [PMID: 27687728 DOI: 10.1074/jbc.m116.744722] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 09/21/2016] [Indexed: 11/06/2022] Open
Abstract
β-Site APP-cleaving enzyme 1 (BACE1) cleaves amyloid β-protein precursor (APP) at the bond between Met671 and Asp672 (β-site) to generate the carboxyl-terminal fragment (CTFβ/C99). BACE1 also cleaves APP at another bond between Thr681 and Gln682 (β'-site), yielding CTFβ'/C89. Cleavage of CTFβ/C99 by γ-secretase generates Aβ(1-XX), whereas cleavage of CTFβ'/C89 generates Aβ(11-XX). Thus, β'-site cleavage by BACE1 is amyloidolytic rather than amyloidogenic. β' cleavage of mouse APP is more common than the corresponding cleavage of human APP. We found that the H684R substitution within human Aβ, which replaces the histidine in the human protein with the arginine found at the corresponding position in mouse, facilitated β' cleavage irrespective of the species origin of BACE1, thereby significantly increasing the level of Aβ(11-XX) and decreasing the level of Aβ(1-XX). Thus, amino acid substitutions within the Aβ sequence influenced the selectivity of alternative β- or β'-site cleavage of APP by BACE1. In familial Alzheimer's disease (FAD), the APP gene harbors pathogenic variations such as the Swedish (K670N/M671L), Leuven (E682K), and A673V mutations, all of which decrease Aβ(11-40) generation, whereas the protective Icelandic mutation (A673T) increases generation of Aβ(11-40). Thus, A673T promotes β' cleavage of APP and protects subjects against AD. In addition, CTFβ/C99 was cleaved by excess BACE1 activity to generate CTFβ'/C89, followed by Aβ(11-40), even if APP harbored pathogenic mutations. The resultant Aβ(11-40) was more metabolically labile in vivo than Aβ(1-40). Our analysis suggests that some FAD mutations in APP are amyloidogenic and/or amyloidolytic via selection of alternative BACE1 cleavage sites.
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Affiliation(s)
- Ayano Kimura
- From the Laboratory of Neuroscience, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12-Nishi 6, Kita-ku, Sapporo 060-0812, Japan
| | - Saori Hata
- From the Laboratory of Neuroscience, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12-Nishi 6, Kita-ku, Sapporo 060-0812, Japan
| | - Toshiharu Suzuki
- From the Laboratory of Neuroscience, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12-Nishi 6, Kita-ku, Sapporo 060-0812, Japan
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Structure of amyloid oligomers and their mechanisms of toxicities: Targeting amyloid oligomers using novel therapeutic approaches. Eur J Med Chem 2016; 114:41-58. [DOI: 10.1016/j.ejmech.2016.02.065] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 02/25/2016] [Accepted: 02/25/2016] [Indexed: 01/22/2023]
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Zhang JS, Zhou SF, Wang Q, Guo JN, Liang HM, Deng JB, He WY. Gastrodin suppresses BACE1 expression under oxidative stress condition via inhibition of the PKR/eIF2α pathway in Alzheimer's disease. Neuroscience 2016; 325:1-9. [PMID: 26987953 DOI: 10.1016/j.neuroscience.2016.03.024] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 02/23/2016] [Accepted: 03/08/2016] [Indexed: 10/22/2022]
Abstract
The expression of β-site APP-cleaving enzyme 1 (BACE1) is increased in the brain of late-onset sporadic Alzheimer's disease (AD) and oxidative stress may be the potential cause of this event. The phenolic glucoside gastrodin (Gas), a main component of a Chinese herbal medicine Gastrodia elata Blume, has been demonstrated to display antioxidant activity and suppresses BACE1 expression. However, the mechanisms by which Gas suppresses BACE1 expression are not clear. Morris water maze test was performed to assess the effect of Gas treatment on memory impairments in Tg2576 mice. The level of oxidative stress in the brain of Tg2576 mice was determined by measuring the superoxide dismutase (SOD) activity, catalase (CAT) activity, and the levels of malondialdehyde (MDA) and ROS. In vivo and in vitro, we detected the expression levels of BACE1, pPKRThr446, PKR, pPERKThr981, PERK, peIF2αSer51, and eIF2α using western blot analysis. We found that Gas improved learning and memory abilities of Tg2576 transgenic mice and attenuated intracellular oxidative stress in hippocampi of Tg2576 mice. We discovered that the expression levels of BACE1, activated PKR (pPKRThr446) and activated eIF2α (peIF2αSer51) were elevated in the brains of Tg2576 mice and hydrogen peroxide (H2O2)-stimulated SH-SY5Y cells. Moreover, peptide PKR inhibitor (PRI) and Gas down-regulated BACE1 expression in Tg2576 mice and H2O2-stimulated SH-SY5Y cells by inhibiting activation of PKR and eIF2α. Gas alleviates memory deficits in mice and suppresses BACE1 expression by inhibiting the protein kinase/Eukaryotic initiation factor-2α (PKR/eIF2α) pathway. The research suggested that Gas may develop as an drug candidate in neurodegenerative diseases.
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Affiliation(s)
- J-S Zhang
- Department of Neurology, Huaihe Hospital of Henan University, Kaifeng 475000, China
| | - S-F Zhou
- Department of Neurology, Huaihe Hospital of Henan University, Kaifeng 475000, China
| | - Q Wang
- Department of Neurology, Huaihe Hospital of Henan University, Kaifeng 475000, China
| | - J-N Guo
- Department of Neurology, Huaihe Hospital of Henan University, Kaifeng 475000, China
| | - H-M Liang
- Department of Neurology, Huaihe Hospital of Henan University, Kaifeng 475000, China
| | - J-B Deng
- Department of Neurology, Huaihe Hospital of Henan University, Kaifeng 475000, China; Department of Neurobiology, College of Life Sciences, Henan University, Kaifeng 475004, China.
| | - W-Y He
- Department of Neurology, Huaihe Hospital of Henan University, Kaifeng 475000, China.
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Sun SW, Nishioka C, Labib W, Liang HF. Axonal Terminals Exposed to Amyloid-β May Not Lead to Pre-Synaptic Axonal Damage. J Alzheimers Dis 2016; 45:1139-48. [PMID: 25697704 DOI: 10.3233/jad-142154] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Synaptic deficits and neuronal loss are the major pathological manifestations of Alzheimer's disease. However, the link between the early synaptic loss and subsequent neurodegeneration is not entirely clear. Cell culture studies have shown that amyloid-β (Aβ) applied to axonal terminals can cause retrograde degeneration leading to the neuronal loss, but this process has not been demonstrated in live animals. OBJECTIVE To test if Aβ applied to retinal ganglion cell axonal terminals can induce axonal damage in the optic nerve and optic tract in mice. METHODS Aβ was injected into the terminal field of the optic tract, in the left lateral geniculate nucleus of wildtype C57BL/6 mice. Following the injection, monthly diffusion tensor imaging was performed. Three months after the injection, mice underwent visual evoked potential recordings, and then sacrificed for immunohistochemical examination. RESULTS There were no significant changes seen with diffusion tensor imaging in the optic nerve and optic tract 3 months after the Aβ injection. The myelin and axons in these regions remained intact according to immunohistochemistry. The only significant changes observed in this study were delayed transduction and reduced amplitude of visual evoked potentials, although both Aβ and its reversed form caused similar changes. CONCLUSION Despite the published in vitro studies, there was no significant axonal damage in the optic nerve and optic tract after injecting Aβ onto retinal ganglion cell axonal terminals of wildtype C57BL/6 mice.
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Affiliation(s)
- Shu-Wei Sun
- Basic Sciences, Schools of Medicine, Loma Linda University, Loma Linda, CA, USA Radiation Medicine, Schools of Medicine, Loma Linda University, Loma Linda, CA, USA Pharmaceutical Science, School of Pharmacy, Loma Linda University, Loma Linda, CA, USA Neuroscience, University of California in Riverside, Riverside, CA, USA Bioengineering, University of California in Riverside, Riverside, CA, USA
| | | | - Wessam Labib
- Family Medicine, Loma Linda University Medical Center, Loma Linda, CA, USA
| | - Hsiao-Fang Liang
- Basic Sciences, Schools of Medicine, Loma Linda University, Loma Linda, CA, USA
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Liu Y, An S, Li J, Kuang Y, He X, Guo Y, Ma H, Zhang Y, Ji B, Jiang C. Brain-targeted co-delivery of therapeutic gene and peptide by multifunctional nanoparticles in Alzheimer's disease mice. Biomaterials 2016; 80:33-45. [DOI: 10.1016/j.biomaterials.2015.11.060] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 11/24/2015] [Accepted: 11/29/2015] [Indexed: 12/31/2022]
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Deng QS, Dong XY, Wu H, Wang W, Wang ZT, Zhu JW, Liu CF, Jia WQ, Zhang Y, Schachner M, Ma QH, Xu RX. Disrupted-in-Schizophrenia-1 Attenuates Amyloid-β Generation and Cognitive Deficits in APP/PS1 Transgenic Mice by Reduction of β-Site APP-Cleaving Enzyme 1 Levels. Neuropsychopharmacology 2016; 41:440-53. [PMID: 26062786 PMCID: PMC5130120 DOI: 10.1038/npp.2015.164] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 04/27/2015] [Accepted: 05/05/2015] [Indexed: 02/05/2023]
Abstract
Disrupted-in-Schizophrenia-1 (DISC1) is a genetic risk factor for a wide range of major mental disorders, including schizophrenia, major depression, and bipolar disorders. Recent reports suggest a potential role of DISC1 in the pathogenesis of Alzheimer's disease (AD), by referring to an interaction between DISC1 and amyloid precursor protein (APP), and to an association of a single-nucleotide polymorphism in a DISC1 intron and late onset of AD. However, the function of DISC1 in AD remains unknown. In this study, decreased levels of DISC1 were observed in the cortex and hippocampus of 8-month-old APP/PS1 transgenic mice, an animal model of AD. Overexpression of DISC1 reduced, whereas knockdown of DISC1 increased protein levels, but not mRNA levels of β-site APP-Cleaving Enzyme 1 (BACE1), a key enzyme in amyloid-β (Aβ) generation. Reduction of BACE1 protein levels by overexpression of DISC1 was accompanied by an accelerating decline rate of BACE1, and was blocked by the lysosomal inhibitor chloroquine, rather than proteasome inhibitor MG-132. Moreover, overexpression of DISC1 in the hippocampus with an adeno-associated virus reduced the levels of BACE1, soluble Aβ40/42, amyloid plaque density, and rescued cognitive deficits of APP/PS1 transgenic mice. These results indicate that DISC1 attenuates Aβ generation and cognitive deficits of APP/PS1 transgenic mice through promoting lysosomal degradation of BACE1. Our findings provide new insights into the role of DISC1 in AD pathogenesis and link a potential function of DISC1 to the psychiatric symptoms of AD.
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Affiliation(s)
- Qing-Shan Deng
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
| | - Xing-Yu Dong
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
| | - Hao Wu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
| | - Wang Wang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
| | - Zhao-Tao Wang
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
| | - Jian-Wei Zhu
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
| | - Chun-Feng Liu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
| | - Wei-Qiang Jia
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
| | - Yan Zhang
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
| | - Melitta Schachner
- Center for Neuroscience, Shantou University Medical College, Shantou, China
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
| | - Quan-Hong Ma
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, China
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute, of Neuroscience, Soochow University, Blk402, Renai Road 199, Suzhou, Jiangsu 215021, China, Tel: +86 18015504376, Fax: +86 512 65880829 E-mail:
| | - Ru-Xiang Xu
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing, China
- Affiliated Bayi Brain Hospital and Affiliated Beijing Military Hospital of Southern Medical University, Beijing 100070, China, Tel: +8613391788118, Fax: +86 10 64057752, E-mail:
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Herbst-Robinson KJ, Liu L, James M, Yao Y, Xie SX, Brunden KR. Inflammatory Eicosanoids Increase Amyloid Precursor Protein Expression via Activation of Multiple Neuronal Receptors. Sci Rep 2015; 5:18286. [PMID: 26672557 PMCID: PMC4682150 DOI: 10.1038/srep18286] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 10/26/2015] [Indexed: 01/27/2023] Open
Abstract
Senile plaques comprised of Aβ peptides are a hallmark of Alzheimer's disease (AD) brain, as are activated glia that release inflammatory molecules, including eicosanoids. Previous studies have demonstrated that amyloid precursor protein (APP) and Aβ levels can be increased through activation of thromboxane A2-prostanoid (TP) receptors on neurons. We demonstrate that TP receptor regulation of APP expression depends on Gαq-signaling and conventional protein kinase C isoforms. Importantly, we discovered that Gαq-linked prostaglandin E2 and leukotriene D4 receptors also regulate APP expression. Prostaglandin E2 and thromboxane A2, as well as total APP levels, were found to be elevated in the brains of aged 5XFAD transgenic mice harboring Aβ plaques and activated glia, suggesting that increased APP expression resulted from eicosanoid binding to Gαq-linked neuronal receptors. Notably, inhibition of eicosanoid synthesis significantly lowered brain APP protein levels in aged 5XFAD mice. These results provide new insights into potential AD therapeutic strategies.
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Affiliation(s)
- Katie J. Herbst-Robinson
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Li Liu
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Michael James
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Yuemang Yao
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Sharon X. Xie
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Kurt R. Brunden
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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Jiang Y, Rigoglioso A, Peterhoff CM, Pawlik M, Sato Y, Bleiwas C, Stavrides P, Smiley JF, Ginsberg SD, Mathews PM, Levy E, Nixon RA. Partial BACE1 reduction in a Down syndrome mouse model blocks Alzheimer-related endosomal anomalies and cholinergic neurodegeneration: role of APP-CTF. Neurobiol Aging 2015; 39:90-8. [PMID: 26923405 DOI: 10.1016/j.neurobiolaging.2015.11.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 11/17/2015] [Accepted: 11/23/2015] [Indexed: 11/30/2022]
Abstract
β-amyloid precursor protein (APP) and amyloid beta peptide (Aβ) are strongly implicated in Alzheimer's disease (AD) pathogenesis, although recent evidence has linked APP-βCTF generated by BACE1 (β-APP cleaving enzyme 1) to the development of endocytic abnormalities and cholinergic neurodegeneration in early AD. We show that partial BACE1 genetic reduction prevents these AD-related pathological features in the Ts2 mouse model of Down syndrome. Partially reducing BACE1 by deleting one BACE1 allele blocked development of age-related endosome enlargement in the medial septal nucleus, cerebral cortex, and hippocampus and loss of choline acetyltransferase (ChAT)-positive medial septal nucleus neurons. BACE1 reduction normalized APP-βCTF elevation but did not alter Aβ40 and Aβ42 peptide levels in brain, supporting a critical role in vivo for APP-βCTF in the development of these abnormalities. Although ameliorative effects of BACE1 inhibition on β-amyloidosis and synaptic proteins levels have been previously noted in AD mouse models, our results highlight the additional potential value of BACE1 modulation in therapeutic targeting of endocytic dysfunction and cholinergic neurodegeneration in Down syndrome and AD.
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Affiliation(s)
- Ying Jiang
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA
| | - Andrew Rigoglioso
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | | | - Monika Pawlik
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - Yutaka Sato
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - Cynthia Bleiwas
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - Philip Stavrides
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - John F Smiley
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA
| | - Stephen D Ginsberg
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA; Department of Neuroscience & Physiology, NYU Langone Medical Center, New York, NY, USA
| | - Paul M Mathews
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA
| | - Efrat Levy
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA; Department of Biochemistry and Molecular Pharmacology, NYU Langone Medical Center, New York, NY, USA
| | - Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, NYU Langone Medical Center, New York, NY, USA; Department of Cell Biology, NYU Langone Medical Center, New York, NY, USA.
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Amlie-Wolf A, Ryvkin P, Tong R, Dragomir I, Suh E, Xu Y, Van Deerlin VM, Gregory BD, Kwong LK, Trojanowski JQ, Lee VMY, Wang LS, Lee EB. Transcriptomic Changes Due to Cytoplasmic TDP-43 Expression Reveal Dysregulation of Histone Transcripts and Nuclear Chromatin. PLoS One 2015; 10:e0141836. [PMID: 26510133 PMCID: PMC4624943 DOI: 10.1371/journal.pone.0141836] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 10/13/2015] [Indexed: 12/13/2022] Open
Abstract
TAR DNA-binding protein 43 (TDP-43) is normally a nuclear RNA-binding protein that exhibits a range of functions including regulation of alternative splicing, RNA trafficking, and RNA stability. However, in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-TDP), TDP-43 is abnormally phosphorylated, ubiquitinated, and cleaved, and is mislocalized to the cytoplasm where it forms distinctive aggregates. We previously developed a mouse model expressing human TDP-43 with a mutation in its nuclear localization signal (ΔNLS-hTDP-43) so that the protein preferentially localizes to the cytoplasm. These mice did not exhibit a significant number of cytoplasmic aggregates, but did display dramatic changes in gene expression as measured by microarray, suggesting that cytoplasmic TDP-43 may be associated with a toxic gain-of-function. Here, we analyze new RNA-sequencing data from the ΔNLS-hTDP-43 mouse model, together with published RNA-sequencing data obtained previously from TDP-43 antisense oligonucleotide (ASO) knockdown mice to investigate further the dysregulation of gene expression in the ΔNLS model. This analysis reveals that the transcriptomic effects of the overexpression of the ΔNLS-hTDP-43 transgene are likely due to a gain of cytoplasmic function. Moreover, cytoplasmic TDP-43 expression alters transcripts that regulate chromatin assembly, the nucleolus, lysosomal function, and histone 3' untranslated region (UTR) processing. These transcriptomic alterations correlate with observed histologic abnormalities in heterochromatin structure and nuclear size in transgenic mouse and human brains.
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Affiliation(s)
- Alexandre Amlie-Wolf
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Paul Ryvkin
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Rui Tong
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Isabelle Dragomir
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, United States of America
| | - EunRan Suh
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Yan Xu
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Vivianna M. Van Deerlin
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Brian D. Gregory
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Linda K. Kwong
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - John Q. Trojanowski
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Virginia M.-Y. Lee
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Li-San Wang
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Edward B. Lee
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
- * E-mail:
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Transcriptional regulation of BACE1 by NFAT3 leads to enhanced amyloidogenic processing. Neurochem Res 2015; 40:829-36. [PMID: 25663301 DOI: 10.1007/s11064-015-1533-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/27/2015] [Accepted: 01/30/2015] [Indexed: 12/23/2022]
Abstract
Deposition of amyloid β (Aβ) to form neuritic plaques in the brain is the pathological hallmark of Alzheimer's disease (AD). Aβ is generated from sequential cleavages of the β-amyloid precursor protein (APP) by the β- and γ-secretases, and β-site APP-cleaving enzyme 1 (BACE1) is the essential β-secretase for Aβ generation. Vulnerable regions in AD brains show increased BACE1 protein levels. However, the underlying mechanism how BACE1 is regulated remains to be further illustrated. Nuclear Factor of Activated T-cells (NFAT) has been implicated in AD pathogenesis. Despite the increasing appreciation for the importance of NFAT-dependent transcription in the nervous system, the regulation and function of specific NFAT isoforms in neurons is poorly understood. In this report we found that both BACE1 and NFAT3 levels were significantly increased in the brains of APP/PS1 transgenic mice. We found that overexpression of NFAT3 resulted in increase of BACE1 promoter activity and BACE1 transcription, while disruption of NFAT3 expression decreased BACE1 gene transcription and protein expression in SAS1 cells. In a addition, overexpression of NFAT3 leads to increase levels of Aβ production. Chromatin immunoprecipitation analysis revealed direct binding of NFAT3 to specific DNA sequences within BACE1 promoter region. Taken together, our results indicate that NFAT is a BACE1 transcription factor. Our study suggests that inhibition of NFAT-mediated BACE1 expression may be a valuable drug target for AD therapy.
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Amyloid-β pathology is attenuated by tauroursodeoxycholic acid treatment in APP/PS1 mice after disease onset. Neurobiol Aging 2014; 36:228-40. [PMID: 25443293 DOI: 10.1016/j.neurobiolaging.2014.08.034] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 07/31/2014] [Accepted: 08/12/2014] [Indexed: 01/06/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder hallmarked by the accumulation of extracellular amyloid-β (Aβ) peptide and intraneuronal hyperphosphorylated tau, as well as chronic neuroinflammation. Tauroursodeoxycholic acid (TUDCA) is an endogenous anti-apoptotic bile acid with potent neuroprotective properties in several experimental models of AD. We have previously reported the therapeutic efficacy of TUDCA treatment before amyloid plaque deposition in APP/PS1 double-transgenic mice. In the present study, we evaluated the protective effects of TUDCA when administrated after the onset of amyloid pathology. APP/PS1 transgenic mice with 7 months of age were injected intraperitoneally with TUDCA (500 mg/kg) every 3 days for 3 months. TUDCA treatment significantly attenuated Aβ deposition in the brain, with a concomitant decrease in Aβ₁₋₄₀ and Aβ₁₋₄₂ levels. The amyloidogenic processing of amyloid precursor protein was also reduced, indicating that TUDCA interferes with Aβ production. In addition, TUDCA abrogated GSK3β hyperactivity, which is highly implicated in tau hyperphosphorylation and glial activation. This effect was likely dependent on the specific activation of the upstream kinase, Akt. Finally, TUDCA treatment decreased glial activation and reduced proinflammatory cytokine messenger RNA expression, while partially rescuing synaptic loss. Overall, our results suggest that TUDCA is a promising therapeutic strategy not only for prevention but also for treatment of AD after disease onset.
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Encalada SE, Goldstein LSB. Biophysical challenges to axonal transport: motor-cargo deficiencies and neurodegeneration. Annu Rev Biophys 2014; 43:141-69. [PMID: 24702007 DOI: 10.1146/annurev-biophys-051013-022746] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Axonal transport is indispensable for the distribution of vesicles, organelles, messenger RNAs (mRNAs), and signaling molecules along the axon. This process is mediated by kinesins and dyneins, molecular motors that bind to cargoes and translocate on microtubule tracks. Tight modulation of motor protein activity is necessary, but little is known about the molecules and mechanisms that regulate transport. Moreover, evidence suggests that transport impairments contribute to the initiation or progression of neurodegenerative diseases, or both, but the mechanisms by which motor activity is affected in disease are unclear. In this review, we discuss some of the physical and biophysical properties that influence motor regulation in healthy neurons. We further discuss the evidence for the role of transport in neurodegeneration, highlighting two pathways that may contribute to transport impairment-dependent disease: genetic mutations or variation, and protein aggregation. Understanding how and when transport parameters change in disease will help delineate molecular mechanisms of neurodegeneration.
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Affiliation(s)
- Sandra E Encalada
- Department of Molecular and Experimental Medicine, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California 92037;
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The clearance of misfolded proteins in neurodegenerative diseases by zinc metalloproteases: An inorganic perspective. Coord Chem Rev 2014. [DOI: 10.1016/j.ccr.2013.10.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Zhang X, Song W. The role of APP and BACE1 trafficking in APP processing and amyloid-β generation. ALZHEIMERS RESEARCH & THERAPY 2013; 5:46. [PMID: 24103387 PMCID: PMC3978418 DOI: 10.1186/alzrt211] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neuritic plaques in the brain are a major neuropathological hallmark of Alzheimer’s disease. They are formed by the deposition and aggregation of extracellular amyloid-β protein (Aβ). Aβ is derived from the sequential cleavage of amyloid-β precursor protein (APP) by β-secretase and γ-secretase. β-Site APP cleaving enzyme 1 (BACE1) functions as the primary, if not sole, β-secretase in vivo and is essential for Aβ production. Regulation of APP processing is a major focus of research into AD pathogenesis. The trafficking systems of APP and its cleavage enzymes are complex. Transporting APP and secretases into the same subcellular organelles facilitates their interaction and favors APP processing. The role of APP and BACE1 trafficking in the amyloidgenic pathway and the underlying mechanisms for Aβ production are discussed in this review. In addition, the distinct mechanisms of amino- and carboxy-terminal Aβ generation are reviewed.
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Affiliation(s)
- Xiaojie Zhang
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, 2255 Wesbrook Mall, Vancouver BC V6T 1Z3, Canada
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, Brain Research Center, Graduate Program in Neuroscience, The University of British Columbia, 2255 Wesbrook Mall, Vancouver BC V6T 1Z3, Canada
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Suh J, Choi SH, Romano DM, Gannon MA, Lesinski AN, Kim DY, Tanzi RE. ADAM10 missense mutations potentiate β-amyloid accumulation by impairing prodomain chaperone function. Neuron 2013; 80:385-401. [PMID: 24055016 DOI: 10.1016/j.neuron.2013.08.035] [Citation(s) in RCA: 152] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2013] [Indexed: 12/22/2022]
Abstract
The generation of Aβ, the main component of senile plaques in Alzheimer's disease (AD), is precluded by α-secretase cleavage within the Aβ domain of the amyloid precursor protein (APP). We identified two rare mutations (Q170H and R181G) in the prodomain of the metalloprotease, ADAM10, that cosegregate with late-onset AD (LOAD). Here, we addressed the pathogenicity of these mutations in transgenic mice expressing human ADAM10 in brain. In Tg2576 AD mice, both mutations attenuated α-secretase activity of ADAM10 and shifted APP processing toward β-secretase-mediated cleavage, while enhancing Aβ plaque load and reactive gliosis. We also demonstrated ADAM10 expression potentiates adult hippocampal neurogenesis, which is reduced by the LOAD mutations. Mechanistically, both LOAD mutations impaired the molecular chaperone activity of ADAM10 prodomain. Collectively, these findings suggest that diminished α-secretase activity, owing to LOAD ADAM10 prodomain mutations, leads to AD-related pathology, strongly supporting ADAM10 as a promising therapeutic target for this devastating disease.
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Affiliation(s)
- Jaehong Suh
- Genetics and Aging Research Unit, MassGeneral Institute of Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02129, USA
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Deng M, He W, Tan Y, Han H, Hu X, Xia K, Zhang Z, Yan R. Increased expression of reticulon 3 in neurons leads to reduced axonal transport of β site amyloid precursor protein-cleaving enzyme 1. J Biol Chem 2013; 288:30236-30245. [PMID: 24005676 DOI: 10.1074/jbc.m113.480079] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
BACE1 is the sole enzyme responsible for cleaving amyloid precursor protein at the β-secretase site, and this cleavage initiates the generation of β-amyloid peptide (Aβ). Because amyloid precursor protein is predominantly expressed by neurons and deposition of Aβ aggregates in the human brain is highly correlated with the Aβ released at axonal terminals, we focused our investigation of BACE1 localization on the neuritic region. We show that BACE1 was not only enriched in the late Golgi, trans-Golgi network, and early endosomes but also in both axons and dendrites. BACE1 was colocalized with the presynaptic vesicle marker synaptophysin, indicating the presence of BACE1 in synapses. Because the excessive release of Aβ from synapses is attributable to an increase in amyloid deposition, we further explored whether the presence of BACE1 in synapses was regulated by reticulon 3 (RTN3), a protein identified previously as a negative regulator of BACE1. We found that RTN3 is not only localized in the endoplasmic reticulum but also in neuritic regions where no endoplasmic reticulum-shaping proteins are detected, implicating additional functions of RTN3 in neurons. Coexpression of RTN3 with BACE1 in cultured neurons was sufficient to reduce colocalization of BACE1 with synaptophysin. This reduction correlated with decreased anterograde transport of BACE1 in axons in response to overexpressed RTN3. Our results in this study suggest that altered RTN3 levels can impact the axonal transport of BACE1 and demonstrate that reducing axonal transport of BACE1 in axons is a viable strategy for decreasing BACE1 in axonal terminals and, perhaps, reducing amyloid deposition.
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Affiliation(s)
- Minzi Deng
- From the State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan 410078, China and
| | - Wanxia He
- the Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Ya Tan
- From the State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan 410078, China and
| | - Hailong Han
- From the State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan 410078, China and
| | - Xiangyou Hu
- the Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Kun Xia
- From the State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan 410078, China and
| | - Zhuohua Zhang
- From the State Key Laboratory of Medical Genetics, Xiangya Medical School, Central South University, Changsha, Hunan 410078, China and.
| | - Riqiang Yan
- the Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195.
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Fan LF, Xu DE, Wang WH, Yan K, Wu H, Yao XQ, Xu RX, Liu CF, Ma QH. Caspr interaction with Amyloid Precursor Protein reduces amyloid-β generation in vitro. Neurosci Lett 2013; 548:255-60. [DOI: 10.1016/j.neulet.2013.05.055] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 05/04/2013] [Accepted: 05/18/2013] [Indexed: 11/15/2022]
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Saido T, Leissring MA. Proteolytic degradation of amyloid β-protein. Cold Spring Harb Perspect Med 2013; 2:a006379. [PMID: 22675659 DOI: 10.1101/cshperspect.a006379] [Citation(s) in RCA: 253] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The amyloid β-protein (Aβ) is subject to proteolytic degradation by a diverse array of peptidases and proteinases, known collectively as Aβ-degrading proteases (AβDPs). A growing number of AβDPs have been identified, which, under physiological and/or pathophysiological conditions, contribute significantly to the determination of endogenous cerebral Aβ levels. Despite more than a decade of investigation, the complete set of AβDPs remains to be established, and our understanding of even well-established AβDPs is incomplete. Nevertheless, the study of known AβDPs has contributed importantly to our understanding of the molecular pathogenesis of Alzheimer disease (AD) and has inspired the development of several novel therapeutic approaches to the regulation of cerebral Aβ levels. In this article, we discuss the general features of Aβ degradation and introduce the best-characterized AβDPs, focusing on their diverse properties and the numerous conceptual insights that have emerged from the study of each.
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Affiliation(s)
- Takaomi Saido
- Riken Brain Science Institute, Saitamo 351-0198, Japan
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Gunawardena S, Yang G, Goldstein LSB. Presenilin controls kinesin-1 and dynein function during APP-vesicle transport in vivo. Hum Mol Genet 2013; 22:3828-43. [PMID: 23710041 DOI: 10.1093/hmg/ddt237] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Neurons and other cells require intracellular transport of essential components for viability and function. Previous work has shown that while net amyloid precursor protein (APP) transport is generally anterograde, individual vesicles containing APP move bi-directionally. This discrepancy highlights our poor understanding of the in vivo regulation of APP-vesicle transport. Here, we show that reduction of presenilin (PS) or suppression of gamma-secretase activity substantially increases anterograde and retrograde velocities for APP vesicles. Strikingly, PS deficiency has no effect on an unrelated cargo vesicle class containing synaptotagmin, which is powered by a different kinesin motor. Increased velocities caused by PS or gamma-secretase reduction require functional kinesin-1 and dynein motors. Together, our findings suggest that a normal function of PS is to repress kinesin-1 and dynein motor activity during axonal transport of APP vesicles. Furthermore, our data suggest that axonal transport defects induced by loss of PS-mediated regulatory effects on APP-vesicle motility could be a major cause of neuronal and synaptic defects observed in Alzheimer's Disease (AD) pathogenesis. Thus, perturbations of APP/PS transport could contribute to early neuropathology observed in AD, and highlight a potential novel therapeutic pathway for early intervention, prior to neuronal loss and clinical manifestation of disease.
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