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Kuhn AJ, Chan K, Sajimon M, Yoo S, Balasco Serrão VH, Lee J, Abrams B, Nowick JS, Uversky VN, Wheeler C, Raskatov JA. Amyloid-α Peptide Formed through Alternative Processing of the Amyloid Precursor Protein Attenuates Alzheimer's Amyloid-β Toxicity via Cross-Chaperoning. J Am Chem Soc 2024; 146:2634-2645. [PMID: 38236059 DOI: 10.1021/jacs.3c11511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Amyloid aggregation is a key feature of Alzheimer's disease (AD) and a primary target for past and present therapeutic efforts. Recent research is making it increasingly clear that the heterogeneity of amyloid deposits, extending past the commonly targeted amyloid-β (Aβ), must be considered for successful therapy. We recently demonstrated that amyloid-α (Aα or p3), a C-terminal peptidic fragment of Aβ, aggregates rapidly to form amyloids and can expedite the aggregation of Aβ through seeding. Here, we advance the understanding of Aα biophysics and biology in several important ways. We report the first cryogenic electron microscopy (cryo-EM) structure of an Aα amyloid fibril, proving unambiguously that the peptide is fibrillogenic. We demonstrate that Aα induces Aβ to form amyloid aggregates that are less toxic than pure Aβ aggregates and use nuclear magnetic resonance spectroscopy (NMR) to provide insights into specific interactions between Aα and Aβ in solution. This is the first evidence that Aα can coassemble with Aβ and alter its biological effects at relatively low concentrations. Based on the above, we urge researchers in the field to re-examine the significance of Aα in AD.
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Affiliation(s)
- Ariel J Kuhn
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Ka Chan
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Maria Sajimon
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Stan Yoo
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Vitor Hugo Balasco Serrão
- Biomolecular Cryoelectron Microscopy Facility, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Jack Lee
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Benjamin Abrams
- Department of Biomolecular Engineering, Life Sciences Microscopy Center, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - James S Nowick
- Department of Chemistry, University of California, Irvine, Irvine, California 92697-2025, United States
| | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Boulevard, MDC07, Tampa, Florida 33612, United States
| | - Christopher Wheeler
- World Brain Mapping Foundation, Society for Brain Mapping & Therapeutics, 860 Via De La Paz, Suite E-1, Pacific Palisades, California 90272-3668, United States
- StemVax Therapeutics (Subsidiary of NovAccess Global), 8584 E. Washington Street #127, Chagrin Falls, Ohio 44023, United States
- StemVax Therapeutics (Subsidiary of NovAccess Global), 2265 E. Foothill Boulevard, Pasadena, California 91107, United States
- T-Neuro Pharma, 1451 Innovation Parkway SE, Suite 600, Albuquerque, New Mexico 87123, United States
- T-Neuro Pharma, P.O. Box 781, Aptos, California 95003, United States
| | - Jevgenij A Raskatov
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
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Bernstein HG, Keilhoff G, Dobrowolny H, Steiner J. The many facets of CD26/dipeptidyl peptidase 4 and its inhibitors in disorders of the CNS - a critical overview. Rev Neurosci 2023; 34:1-24. [PMID: 35771831 DOI: 10.1515/revneuro-2022-0026] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/10/2022] [Indexed: 01/11/2023]
Abstract
Dipeptidyl peptidase 4 is a serine protease that cleaves X-proline or X-alanine in the penultimate position. Natural substrates of the enzyme are glucagon-like peptide-1, glucagon inhibiting peptide, glucagon, neuropeptide Y, secretin, substance P, pituitary adenylate cyclase-activating polypeptide, endorphins, endomorphins, brain natriuretic peptide, beta-melanocyte stimulating hormone and amyloid peptides as well as some cytokines and chemokines. The enzyme is involved in the maintenance of blood glucose homeostasis and regulation of the immune system. It is expressed in many organs including the brain. DPP4 activity may be effectively depressed by DPP4 inhibitors. Apart from enzyme activity, DPP4 acts as a cell surface (co)receptor, associates with adeosine deaminase, interacts with extracellular matrix, and controls cell migration and differentiation. This review aims at revealing the impact of DPP4 and DPP4 inhibitors for several brain diseases (virus infections affecting the brain, tumours of the CNS, neurological and psychiatric disorders). Special emphasis is given to a possible involvement of DPP4 expressed in the brain.While prominent contributions of extracerebral DPP4 are evident for a majority of diseases discussed herein; a possible role of "brain" DPP4 is restricted to brain cancers and Alzheimer disease. For a number of diseases (Covid-19 infection, type 2 diabetes, Alzheimer disease, vascular dementia, Parkinson disease, Huntington disease, multiple sclerosis, stroke, and epilepsy), use of DPP4 inhibitors has been shown to have a disease-mitigating effect. However, these beneficial effects should mostly be attributed to the depression of "peripheral" DPP4, since currently used DPP4 inhibitors are not able to pass through the intact blood-brain barrier.
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Affiliation(s)
- Hans-Gert Bernstein
- Department of Psychiatry and Psychotherapy, Otto v. Guericke University Magdeburg, Leipziger Str. 44, D-39120 Magdeburg, Germany
| | - Gerburg Keilhoff
- Institute of Biochemistry and Cell Biology, Otto v. Guericke University Magdeburg, Leipziger Str. 44, D-39120 Magdeburg, Germany
| | - Henrik Dobrowolny
- Department of Psychiatry and Psychotherapy, Otto v. Guericke University Magdeburg, Leipziger Str. 44, D-39120 Magdeburg, Germany
| | - Johann Steiner
- Department of Psychiatry and Psychotherapy, Otto v. Guericke University Magdeburg, Leipziger Str. 44, D-39120 Magdeburg, Germany
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3
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Abstract
Amyloid-β (Aβ) peptides are involved in Alzheimer's disease (AD) development. The interactions of these peptides with copper and zinc ions also seem to be crucial for this pathology. Although Cu(II) and Zn(II) ions binding by Aβ peptides has been scrupulously investigated, surprisingly, this phenomenon has not been so thoroughly elucidated for N-truncated Aβ4-x-probably the most common version of this biomolecule. This negligence also applies to mixed Cu-Zn complexes. From the structural in silico analysis presented in this work, it appears that there are two possible mixed Cu-Zn(Aβ4-x) complexes with different stoichiometries and, consequently, distinct properties. The Cu-Zn(Aβ4-x) complex with 1:1:1 stoichiometry may have a neuroprotective superoxide dismutase-like activity. On the other hand, another mixed 2:1:2 Cu-Zn(Aβ4-x) complex is perhaps a seed for toxic oligomers. Hence, this work proposes a novel research direction for our better understanding of AD development.
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4
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Discovery of a novel pseudo β-hairpin structure of N-truncated amyloid-β for use as a vaccine against Alzheimer's disease. Mol Psychiatry 2022; 27:840-848. [PMID: 34776512 DOI: 10.1038/s41380-021-01385-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 10/16/2021] [Accepted: 10/27/2021] [Indexed: 12/21/2022]
Abstract
One of the hallmarks of Alzheimer's disease (AD) are deposits of amyloid-beta (Aβ) protein in amyloid plaques in the brain. The Aβ peptide exists in several forms, including full-length Aβ1-42 and Aβ1-40 - and the N-truncated species, pyroglutamate Aβ3-42 and Aβ4-42, which appear to play a major role in neurodegeneration. We previously identified a murine antibody (TAP01), which binds specifically to soluble, non-plaque N-truncated Aβ species. By solving crystal structures for TAP01 family antibodies bound to pyroglutamate Aβ3-14, we identified a novel pseudo β-hairpin structure in the N-terminal region of Aβ and show that this underpins its unique binding properties. We engineered a stabilised cyclic form of Aβ1-14 (N-Truncated Amyloid Peptide AntibodieS; the 'TAPAS' vaccine) and showed that this adopts the same 3-dimensional conformation as the native sequence when bound to TAP01. Active immunisation of two mouse models of AD with the TAPAS vaccine led to a striking reduction in amyloid-plaque formation, a rescue of brain glucose metabolism, a stabilisation in neuron loss, and a rescue of memory deficiencies. Treating both models with the humanised version of the TAP01 antibody had similar positive effects. Here we report the discovery of a unique conformational epitope in the N-terminal region of Aβ, which offers new routes for active and passive immunisation against AD.
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5
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Pyroglutamate Aβ cascade as drug target in Alzheimer's disease. Mol Psychiatry 2022; 27:1880-1885. [PMID: 34880449 PMCID: PMC9126800 DOI: 10.1038/s41380-021-01409-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/19/2021] [Accepted: 11/25/2021] [Indexed: 02/07/2023]
Abstract
One of the central aims in Alzheimer's disease (AD) research is the identification of clinically relevant drug targets. A plethora of potential molecular targets work very well in preclinical model systems both in vitro and in vivo in AD mouse models. However, the lack of translation into clinical settings in the AD field is a challenging endeavor. Although it is long known that N-terminally truncated and pyroglutamate-modified Abeta (AβpE3) peptides are abundantly present in the brain of AD patients, form stable and soluble low-molecular weight oligomers, and induce neurodegeneration in AD mouse models, their potential as drug target has not been generally accepted in the past. This situation has dramatically changed with the report that passive immunization with donanemab, an AβpE3-specific antibody, cleared aymloid plaques and stabilized cognitive deficits in a group of patients with mild AD in a phase II trial. This review summarizes the current knowledge on the molecular mechanisms of generation of AβpE, its biochemical properties, and the intervention points as a drug target in AD.
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Effects of Aβ-derived peptide fragments on fibrillogenesis of Aβ. Sci Rep 2021; 11:19262. [PMID: 34584131 PMCID: PMC8479085 DOI: 10.1038/s41598-021-98644-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 09/13/2021] [Indexed: 11/08/2022] Open
Abstract
Amyloid β (Aβ) peptide aggregation plays a central role in Alzheimer's disease (AD) etiology. AD drug candidates have included small molecules or peptides directed towards inhibition of Aβ fibrillogenesis. Although some Aβ-derived peptide fragments suppress Aβ fibril growth, comprehensive analysis of inhibitory potencies of peptide fragments along the whole Aβ sequence has not been reported. The aim of this work is (a) to identify the region(s) of Aβ with highest propensities for aggregation and (b) to use those fragments to inhibit Aβ fibrillogenesis. Structural and aggregation properties of the parent Aβ1-42 peptide and seven overlapping peptide fragments have been studied, i.e. Aβ1-10 (P1), Aβ6-15 (P2), Aβ11-20 (P3), Aβ16-25 (P4), Aβ21-30 (P5), Aβ26-36 (P6), and Aβ31-42 (P7). Structural transitions of the peptides in aqueous buffer have been monitored by circular dichroism and Fourier transform infrared spectroscopy. Aggregation and fibrillogenesis were analyzed by light scattering and thioflavin-T fluorescence. The mode of peptide-peptide interactions was characterized by fluorescence resonance energy transfer. Three peptide fragments, P3, P6, and P7, exhibited exceptionally high propensity for β-sheet formation and aggregation. Remarkably, only P3 and P6 exerted strong inhibitory effect on the aggregation of Aβ1-42, whereas P7 and P2 displayed moderate inhibitory potency. It is proposed that P3 and P6 intercalate between Aβ1-42 molecules and thereby inhibit Aβ1-42 aggregation. These findings may facilitate therapeutic strategies of inhibition of Aβ fibrillogenesis by Aβ-derived peptides.
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7
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Bayer TA. N-Truncated Aβ Starting at Position Four-Biochemical Features, Preclinical Models, and Potential as Drug Target in Alzheimer's Disease. Front Aging Neurosci 2021; 13:710579. [PMID: 34489680 PMCID: PMC8417877 DOI: 10.3389/fnagi.2021.710579] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 07/29/2021] [Indexed: 12/21/2022] Open
Abstract
The discussion of whether amyloid plaque Aβ is a valid drug target to fight Alzheimer’s disease (AD) has been a matter of scientific dispute for decades. This question can only be settled by successful clinical trials and the approval of disease-modifying drugs. However, many clinical trials with antibodies against different regions of the amyloid Aβ peptide have been discontinued, as they did not meet the clinical endpoints required. Recently, passive immunization of AD patients with Donanemab, an antibody directed against the N-terminus of pyroglutamate Aβ, showed beneficial effects in a phase II trial, supporting the concept that N-truncated Aβ is a relevant target for AD therapy. There is long-standing evidence that N-truncated Aβ variants are the main variants found in amyloid plaques besides full-length Aβ1–42, t, therefore their role in triggering AD pathology and as targets for drug development are of interest. While the contribution of pyroglutamate Aβ3–42 to AD pathology has been well studied in the past, the potential role of Aβ4–42 has been largely neglected. The present review will therefore focus on Aβ4–42 as a possible drug target based on human and mouse pathology, in vitro and in vivo toxicity, and anti-Aβ4-X therapeutic effects in preclinical models.
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Affiliation(s)
- Thomas A Bayer
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center Göttingen (UMG), Georg-August-University, Göttingen, Germany
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Fasae KD, Abolaji AO, Faloye TR, Odunsi AY, Oyetayo BO, Enya JI, Rotimi JA, Akinyemi RO, Whitworth AJ, Aschner M. Metallobiology and therapeutic chelation of biometals (copper, zinc and iron) in Alzheimer's disease: Limitations, and current and future perspectives. J Trace Elem Med Biol 2021; 67:126779. [PMID: 34034029 DOI: 10.1016/j.jtemb.2021.126779] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 04/03/2021] [Accepted: 05/10/2021] [Indexed: 02/08/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) is the most prevalent cause of cognitive impairment and dementia worldwide. The pathobiology of the disease has been studied in the form of several hypotheses, ranging from oxidative stress, amyloid-beta (Aβ) aggregation, accumulation of tau forming neurofibrillary tangles (NFT) through metal dysregulation and homeostasis, dysfunction of the cholinergic system, and to inflammatory and autophagic mechanism. However, none of these hypotheses has led to confirmed diagnostics or approved cure for the disease. OBJECTIVE This review is aimed as a basic and an encyclopedic short course into metals in AD and discusses the advances in chelation strategies and developments adopted in the treatment of the disease. Since there is accumulating evidence of the role of both biometal dyshomeostasis (iron (Fe), copper (Cu), and zinc (Zn)) and metal-amyloid interactions that lead to the pathogenesis of AD, this review focuses on unraveling therapeutic chelation strategies that have been considered in the treatment of the disease, aiming to sequester free and protein-bound metal ions and reducing cerebral metal burden. Promising compounds possessing chemically modified moieties evolving as multi-target ligands used as anti-AD drug candidates are also covered. RESULTS AND CONCLUSION Several multidirectional and multifaceted studies on metal chelation therapeutics show the need for improved synthesis, screening, and analysis of compounds to be able to effectively present chelating anti-AD drugs. Most drug candidates studied have limitations in their physicochemical properties; some enhance redistribution of metal ions, while others indirectly activate signaling pathways in AD. The metal chelation process in vivo still needs to be established and the design of potential anti-AD compounds that bi-functionally sequester metal ions as well as inhibit the Aβ aggregation by competing with the metal ions and reducing metal-induced oxidative damage and neurotoxicity may signal a bright end in chelation-based therapeutics of AD.
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Affiliation(s)
- Kehinde D Fasae
- Department of Biochemistry, Molecular Drug Metabolism and Toxicology Unit, College of Medicine, University of Ibadan, Nigeria
| | - Amos O Abolaji
- Department of Biochemistry, Molecular Drug Metabolism and Toxicology Unit, College of Medicine, University of Ibadan, Nigeria.
| | - Tolulope R Faloye
- Department of Biochemistry, Molecular Drug Metabolism and Toxicology Unit, College of Medicine, University of Ibadan, Nigeria
| | - Atinuke Y Odunsi
- Department of Biochemistry, Molecular Drug Metabolism and Toxicology Unit, College of Medicine, University of Ibadan, Nigeria
| | - Bolaji O Oyetayo
- Department of Pharmacology and Therapeutics, Neuropharmacology Unit, College of Medicine, University of Ibadan, Nigeria
| | - Joseph I Enya
- Department of Anatomy, University of Ilorin, Kwara State, Nigeria
| | - Joshua A Rotimi
- Department of Biochemistry and Molecular Biology, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Rufus O Akinyemi
- Neuroscience and Ageing Research Unit, Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria
| | | | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA.
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Xu C, Wang YN, Wu H. Glutaminyl Cyclase, Diseases, and Development of Glutaminyl Cyclase Inhibitors. J Med Chem 2021; 64:6549-6565. [PMID: 34000808 DOI: 10.1021/acs.jmedchem.1c00325] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pyroglutamate (pE) modification, catalyzed mainly by glutaminyl cyclase (QC), is prevalent throughout nature and is particularly important in mammals including humans for the maturation of hormones, peptides, and proteins. In humans, the upregulation of QC is involved in multiple diseases and conditions including Alzheimer's disease, Huntington's disease, melanomas, thyroid carcinomas, accelerated atherosclerosis, septic arthritics, etc. This upregulation catalyzes the generation of modified mediators such as pE-amyloid beta (Aß) and pE-chemokine ligand 2 (CCL2) peptides. Not surprisingly, QC has emerged as a reasonable target for the development of therapeutics to combat these diseases and conditions. In this manuscript the deleterious effects of upregulated QC resulting in disease manifestation are reviewed, along with progress on the development of QC inhibitors.
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Affiliation(s)
- Chenshu Xu
- School of Pharmaceutical Sciences, Health Science Center, Shenzhen University, Shenzhen 518060, China
| | - Yi-Nan Wang
- School of Pharmaceutical Sciences, Health Science Center, Shenzhen University, Shenzhen 518060, China
| | - Haiqiang Wu
- School of Pharmaceutical Sciences, Health Science Center, Shenzhen University, Shenzhen 518060, China
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10
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The Aggregation Pattern of Aβ
1–40
is Altered by the Presence of
N
‐Truncated Aβ
4–40
and/or Cu
II
in a Similar Way through Ionic Interactions. Chemistry 2021; 27:2798-2809. [DOI: 10.1002/chem.202004484] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Indexed: 12/19/2022]
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11
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Neuron Loss in Alzheimer's Disease: Translation in Transgenic Mouse Models. Int J Mol Sci 2020; 21:ijms21218144. [PMID: 33143374 PMCID: PMC7663280 DOI: 10.3390/ijms21218144] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 10/28/2020] [Accepted: 10/28/2020] [Indexed: 02/07/2023] Open
Abstract
Transgenic mouse models represent an essential tool for the exploration of Alzheimer’s disease (AD) pathological mechanisms and the development of novel treatments, which at present provide only symptomatic and transient effects. While a variety of mouse models successfully reflects the main neuropathological hallmarks of AD, such as extracellular amyloid-β (Aβ) deposits, intracellular accumulation of Tau protein, the development of micro- and astrogliosis, as well as behavioral deficits, substantial neuron loss, as a key feature of the disease, seems to be more difficult to achieve. In this review, we summarize information on classic and more recent transgenic mouse models for AD, focusing in particular on loss of pyramidal, inter-, and cholinergic neurons. Although the cause of neuron loss in AD is still a matter of scientific debate, it seems to be linked to intraneuronal Aβ accumulation in several transgenic mouse models, especially in pyramidal neurons.
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Kuiperij HB, Hondius DC, Kersten I, Versleijen AAM, Rozemuller AJM, Greenberg SM, Schreuder FHBM, Klijn CJM, Verbeek MM. Apolipoprotein D: a potential biomarker for cerebral amyloid angiopathy. Neuropathol Appl Neurobiol 2020; 46:431-440. [PMID: 31872472 DOI: 10.1111/nan.12595] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 12/18/2019] [Indexed: 01/08/2023]
Abstract
AIMS We investigated the potential of apolipoprotein D (apoD) as cerebrospinal fluid (CSF) biomarker for cerebral amyloid angiopathy (CAA) after confirmation of its association with CAA pathology in human brain tissue. METHODS The association of apoD with CAA pathology was analysed in human occipital lobe tissue of CAA (n = 9), Alzheimer's disease (AD) (n = 11) and healthy control cases (n = 11). ApoD levels were quantified in an age- and sex-matched CSF cohort of CAA patients (n = 31), AD patients (n = 27) and non-neurological controls (n = 67). The effects of confounding factors (age, sex, serum levels) on apoD levels were studied using CSF of non-neurological controls (age range 16-85 years), and paired CSF and serum samples. RESULTS ApoD was strongly associated with amyloid deposits in vessels, but not with parenchymal plaques in human brain tissue. CSF apoD levels correlated with age and were higher in men than women in subjects >50 years. The apoD CSF/serum ratio correlated with the albumin ratio. When controlling for confounding factors, CSF apoD levels were significantly lower in CAA patients compared with controls and compared with AD patients (P = 0.0008). CONCLUSIONS Our data show that apoD is specifically associated with CAA pathology and may be a CSF biomarker for CAA, but clinical application is complicated due to dependency on age, sex and blood-CSF barrier integrity. Well-controlled follow-up studies are required to determine whether apoD can be used as reliable biomarker for CAA.
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Affiliation(s)
- H B Kuiperij
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - D C Hondius
- Department of Pathology, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands.,Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - I Kersten
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - A A M Versleijen
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - A J M Rozemuller
- Department of Pathology, Neuroscience Campus Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
| | - S M Greenberg
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - F H B M Schreuder
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
| | - C J M Klijn
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
| | - M M Verbeek
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
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13
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Teng X, Stefaniak E, Girvan P, Kotuniak R, Płonka D, Bal W, Ying L. Hierarchical binding of copperII to N-truncated Aβ4–16 peptide. Metallomics 2020; 12:470-473. [DOI: 10.1039/c9mt00299e] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Multiple intermediates were found in Cu(ii) binding to Aβ4–16 before the formation of a tight complex.
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Affiliation(s)
- Xiangyu Teng
- Department of Chemistry
- Imperial College London
- Molecular Sciences Research Hub
- White City Campus
- London W12 0BZ
| | - Ewelina Stefaniak
- Institute of Biochemistry and Biophysics
- Polish Academy of Sciences
- 02-106 Warsaw
- Poland
| | - Paul Girvan
- Department of Chemistry
- Imperial College London
- Molecular Sciences Research Hub
- White City Campus
- London W12 0BZ
| | - Radosław Kotuniak
- Institute of Biochemistry and Biophysics
- Polish Academy of Sciences
- 02-106 Warsaw
- Poland
| | - Dawid Płonka
- Institute of Biochemistry and Biophysics
- Polish Academy of Sciences
- 02-106 Warsaw
- Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics
- Polish Academy of Sciences
- 02-106 Warsaw
- Poland
| | - Liming Ying
- National Heart and Lung Institute
- Imperial College London
- Molecular Sciences Research Hub
- White City Campus
- London W12 0BZ
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14
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Hillen H. The Beta Amyloid Dysfunction (BAD) Hypothesis for Alzheimer's Disease. Front Neurosci 2019; 13:1154. [PMID: 31787864 PMCID: PMC6853841 DOI: 10.3389/fnins.2019.01154] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 10/14/2019] [Indexed: 02/05/2023] Open
Abstract
Beta amyloid, Aβ 1–42, originally named as Amyloid A4 protein, is one of the most investigated peptides in neuroscience and has attracted substantial interest since its discovery as the main insoluble fibril-type protein in cerebrovascular amyloid angiopathy (Glenner and Wong, 1984; Masters et al., 1985) of Alzheimer’s disease (AD). From the very beginning, Aβ was regarded per se as a “bad molecule,” triggering the so-called “beta amyloid cascade hypothesis” (Hardy and Higgins, 1992). This hypothesis ignored any physiological function for in situ generated Aβ monomer with normal production and turnover rate (Bateman et al., 2006). Accordingly, pan-Aβ-related therapeutic approaches were designed to eliminate or lower the three structural isoforms in parallel: (1) the pre-amyloid monomer, (2) the misfolded oligomer, and (3) the final fibril. While we already knew about poor correlations between plaques and cognitive decline quite early (Terry et al., 1991), data for an essential benign physiological role for Aβ monomer at low concentrations were also not considered to be relevant. Here, a different Beta Amyloid hypothesis is described, the so-called “Beta Amyloid Dysfunction hypothesis,” which, in contrast to the “Beta Amyloid Cascade hypothesis,” builds on the homeostasis of essential Aβ monomer in the synaptic vesicle cycle (SVC). Disease-relevant early pathology emerges through disturbance of the Aβ homeostasis by so far unknown factors leading to the formation of misfolded Aβ oligomers. These early species interfere with the synaptic physiological Aβ monomer regulation and exert their neurotoxicity via various receptors for sticky oligomer-type Aβ aggregates. The Beta Amyloid Dysfunction (BAD) hypothesis is introduced and shown to explain negative clinical results of Gamma-secretase and Beta-secretase (BACE) inhibitors as well as pan-Aβ isotype unselective immunotherapies. This hypothesis gives guidance to what needs to be done therapeutically to revive successful clinical testing in AD for this highly validated target. The BAD hypothesis will need further refinement in particular through more detailed exploration for the role of physiological Aβ monomer.
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15
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Stefaniak E, Bal W. Cu II Binding Properties of N-Truncated Aβ Peptides: In Search of Biological Function. Inorg Chem 2019; 58:13561-13577. [PMID: 31304745 DOI: 10.1021/acs.inorgchem.9b01399] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
As life expectancy increases, the number of people affected by progressive and irreversible dementia, Alzheimer's Disease (AD), is predicted to grow. No drug designs seem to be working in humans, apparently because the origins of AD have not been identified. Invoking amyloid cascade, metal ions, and ROS production hypothesis of AD, herein we share our point of view on Cu(II) binding properties of Aβ4-x, the most prevalent N-truncated Aβ peptide, currently known as the main constituent of amyloid plaques. The capability of Aβ4-x to rapidly take over copper from previously tested Aβ1-x peptides and form highly stable complexes, redox unreactive and resistant to copper exchange reactions, prompted us to propose physiological roles for these peptides. We discuss the new findings on the reactivity of Cu(II)Aβ4-x with coexisting biomolecules in the context of synaptic cleft; we suggest that the role of Aβ4-x peptides is to quench Cu(II) toxicity in the brain and maintain neurotransmission.
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Affiliation(s)
- Ewelina Stefaniak
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
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16
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Kehoe PG. The Coming of Age of the Angiotensin Hypothesis in Alzheimer's Disease: Progress Toward Disease Prevention and Treatment? J Alzheimers Dis 2019; 62:1443-1466. [PMID: 29562545 PMCID: PMC5870007 DOI: 10.3233/jad-171119] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
There is wide recognition of a complex association between midlife hypertension and cardiovascular disease and later development of Alzheimer’s disease (AD) and cognitive impairment. While significant progress has been made in reducing rates of mortality and morbidity due to cardiovascular disease over the last thirty years, progress towards effective treatments for AD has been slower. Despite the known association between hypertension and dementia, research into each disease has largely been undertaken in parallel and independently. Yet over the last decade and a half, the emergence of converging findings from pre-clinical and clinical research has shown how the renin angiotensin system (RAS), which is very important in blood pressure regulation and cardiovascular disease, warrants careful consideration in the pathogenesis of AD. Numerous components of the RAS have now been found to be altered in AD such that the multifunctional and potent vasoconstrictor angiotensin II, and similarly acting angiotensin III, are greatly altered at the expense of other RAS signaling peptides considered to contribute to neuronal and cognitive function. Collectively these changes may contribute to many of the neuropathological hallmarks of AD, as well as observed progressive deficiencies in cognitive function, while also linking elements of a number of the proposed hypotheses for the cause of AD. This review discusses the emergence of the RAS and its likely importance in AD, not only because of the multiple facets of its involvement, but also perhaps fortuitously because of the ready availability of numerous RAS-acting drugs, that could be repurposed as interventions in AD.
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Affiliation(s)
- Patrick Gavin Kehoe
- Dementia Research Group, Translational Health Sciences, Bristol Medical School, University of Bristol, Southmead Hospital, Bristol, UK
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17
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Walter S, Jumpertz T, Hüttenrauch M, Ogorek I, Gerber H, Storck SE, Zampar S, Dimitrov M, Lehmann S, Lepka K, Berndt C, Wiltfang J, Becker-Pauly C, Beher D, Pietrzik CU, Fraering PC, Wirths O, Weggen S. The metalloprotease ADAMTS4 generates N-truncated Aβ4-x species and marks oligodendrocytes as a source of amyloidogenic peptides in Alzheimer's disease. Acta Neuropathol 2019; 137:239-257. [PMID: 30426203 DOI: 10.1007/s00401-018-1929-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 10/17/2018] [Accepted: 11/04/2018] [Indexed: 02/06/2023]
Abstract
Brain accumulation and aggregation of amyloid-β (Aβ) peptides is a critical step in the pathogenesis of Alzheimer's disease (AD). Full-length Aβ peptides (mainly Aβ1-40 and Aβ1-42) are produced through sequential proteolytic cleavage of the amyloid precursor protein (APP) by β- and γ-secretases. However, studies of autopsy brain samples from AD patients have demonstrated that a large fraction of insoluble Aβ peptides are truncated at the N-terminus, with Aβ4-x peptides being particularly abundant. Aβ4-x peptides are highly aggregation prone, but their origin and any proteases involved in their generation are unknown. We have identified a recognition site for the secreted metalloprotease ADAMTS4 (a disintegrin and metalloproteinase with thrombospondin motifs 4) in the Aβ peptide sequence, which facilitates Aβ4-x peptide generation. Inducible overexpression of ADAMTS4 in HEK293 cells resulted in the secretion of Aβ4-40 but unchanged levels of Aβ1-x peptides. In the 5xFAD mouse model of amyloidosis, Aβ4-x peptides were present not only in amyloid plaque cores and vessel walls, but also in white matter structures co-localized with axonal APP. In the ADAMTS4-/- knockout background, Aβ4-40 levels were reduced confirming a pivotal role of ADAMTS4 in vivo. Surprisingly, in the adult murine brain, ADAMTS4 was exclusively expressed in oligodendrocytes. Cultured oligodendrocytes secreted a variety of Aβ species, but Aβ4-40 peptides were absent in cultures derived from ADAMTS4-/- mice indicating that the enzyme was essential for Aβ4-x production in this cell type. These findings establish an enzymatic mechanism for the generation of Aβ4-x peptides. They further identify oligodendrocytes as a source of these highly amyloidogenic Aβ peptides.
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18
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Dunys J, Valverde A, Checler F. Are N- and C-terminally truncated Aβ species key pathological triggers in Alzheimer's disease? J Biol Chem 2018; 293:15419-15428. [PMID: 30143530 DOI: 10.1074/jbc.r118.003999] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The histopathology of Alzheimer's disease (AD) is characterized by neuronal loss, neurofibrillary tangles, and senile plaque formation. The latter results from an exacerbated production (familial AD cases) or altered degradation (sporadic cases) of 40/42-amino acid-long β-amyloid peptides (Aβ peptides) that are produced by sequential cleavages of Aβ precursor protein (βAPP) by β- and γ-secretases. The amyloid cascade hypothesis proposes a key role for the full-length Aβ42 and the Aβ40/42 ratio in AD etiology, in which soluble Aβ oligomers lead to neurotoxicity, tau hyperphosphorylation, aggregation, and, ultimately, cognitive defects. However, following this postulate, during the last decade, several clinical approaches aimed at decreasing full-length Aβ42 production or neutralizing it by immunotherapy have failed to reduce or even stabilize AD-related decline. Thus, the Aβ peptide (Aβ40/42)-centric hypothesis is probably a simplified view of a much more complex situation involving a multiplicity of APP fragments and Aβ catabolites. Indeed, biochemical analyses of AD brain deposits and fluids have unraveled an Aβ peptidome consisting of additional Aβ-related species. Such Aβ catabolites could be due to either primary enzymatic cleavages of βAPP or secondary processing of Aβ itself by exopeptidases. Here, we review the diversity of N- and C-terminally truncated Aβ peptides and their biosynthesis and outline their potential function/toxicity. We also highlight their potential as new pharmaceutical targets and biomarkers.
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Affiliation(s)
- Julie Dunys
- From the Université Côte d'Azur, INSERM, CNRS, IPMC, Team labeled "Laboratory of Excellence (LABEX) Distalz," 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France
| | - Audrey Valverde
- From the Université Côte d'Azur, INSERM, CNRS, IPMC, Team labeled "Laboratory of Excellence (LABEX) Distalz," 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France
| | - Frédéric Checler
- From the Université Côte d'Azur, INSERM, CNRS, IPMC, Team labeled "Laboratory of Excellence (LABEX) Distalz," 660 Route des Lucioles, Sophia-Antipolis, 06560 Valbonne, France
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19
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Li G, Yang WY, Zhao YF, Chen YX, Hong L, Li YM. Differential Modulation of the Aggregation of N-Terminal Truncated Aβ using Cucurbiturils. Chemistry 2018; 24:13647-13653. [DOI: 10.1002/chem.201802655] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Gao Li
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry; Tsinghua University; 100084 Beijing China
| | - Wu-Yue Yang
- Zhou Pei-Yuan Center for Applied Mathematics; Department of, Mathematical Sciences; Tsinghua University; 100084 Beijing China
| | - Yu-Fen Zhao
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry; Tsinghua University; 100084 Beijing China
| | - Yong-Xiang Chen
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry; Tsinghua University; 100084 Beijing China
| | - Liu Hong
- Zhou Pei-Yuan Center for Applied Mathematics; Department of, Mathematical Sciences; Tsinghua University; 100084 Beijing China
| | - Yan-Mei Li
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry; Tsinghua University; 100084 Beijing China
- Beijing Institute for Brain Disorders; 100069 Beijing China
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20
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Gerth J, Kumar S, Rijal Upadhaya A, Ghebremedhin E, von Arnim CAF, Thal DR, Walter J. Modified amyloid variants in pathological subgroups of β-amyloidosis. Ann Clin Transl Neurol 2018; 5:815-831. [PMID: 30009199 PMCID: PMC6043770 DOI: 10.1002/acn3.577] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 03/21/2018] [Accepted: 04/16/2018] [Indexed: 12/22/2022] Open
Abstract
Objective Amyloid β (Aβ) depositions in plaques and cerebral amyloid angiopathy (CAA) represent common features of Alzheimer's disease (AD). Sequential deposition of post-translationally modified Aβ in plaques characterizes distinct biochemical stages of Aβ maturation. However, the molecular composition of vascular Aβ deposits in CAA and its relation to plaques remain enigmatic. Methods Vascular and parenchymal deposits were immunohistochemically analyzed for pyroglutaminated and phosphorylated Aβ in the medial temporal and occipital lobe of 24 controls, 27 pathologically-defined preclinical AD, and 20 symptomatic AD cases. Results Sequential deposition of Aβ in CAA resembled Aβ maturation in plaques and enabled the distinction of three biochemical stages of CAA. B-CAA stage 1 was characterized by deposition of Aβ in the absence of pyroglutaminated AβN3pE and phosphorylated AβpS8. B-CAA stage 2 showed additional AβN3pE and B-CAA stage 3 additional AβpS8. Based on the Aβ maturation staging in CAA and plaques, three case groups for Aβ pathology could be distinguished: group 1 with advanced Aβ maturation in CAA; group 2 with equal Aβ maturation in CAA and plaques; group 3 with advanced Aβ maturation in plaques. All symptomatic AD cases presented with end-stage plaque maturation, whereas CAA could exhibit immature Aβ deposits. Notably, Aβ pathology group 1 was associated with arterial hypertension, and group 2 with the development of dementia. Interpretation Balance of Aβ maturation in CAA and plaques defines distinct pathological subgroups of β-amyloidosis. The association of CAA-related Aβ maturation with cognitive decline, the individual contribution of CAA and plaque pathology to the development of dementia within the defined Aβ pathology subgroups, and the subgroup-related association with arterial hypertension should be considered for differential diagnosis and therapeutic intervention.
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Affiliation(s)
- Janina Gerth
- Department of Neurology University of Bonn Bonn Germany
| | - Sathish Kumar
- Department of Neurology University of Bonn Bonn Germany
| | - Ajeet Rijal Upadhaya
- Laboratory for Neuropathology Institute for Pathology University of Ulm Ulm Germany
| | | | | | - Dietmar R Thal
- Laboratory for Neuropathology Institute for Pathology University of Ulm Ulm Germany.,Department of Neurosciences KU Leuven Leuven Belgium.,Department of Pathology UZ Leuven Leuven Belgium
| | - Jochen Walter
- Department of Neurology University of Bonn Bonn Germany
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21
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Sumner IL, Edwards RA, Asuni AA, Teeling JL. Antibody Engineering for Optimized Immunotherapy in Alzheimer's Disease. Front Neurosci 2018; 12:254. [PMID: 29740272 PMCID: PMC5924811 DOI: 10.3389/fnins.2018.00254] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/03/2018] [Indexed: 12/17/2022] Open
Abstract
There are nearly 50 million people with Alzheimer's disease (AD) worldwide and currently no disease modifying treatment is available. AD is characterized by deposits of Amyloid-β (Aβ), neurofibrillary tangles, and neuroinflammation, and several drug discovery programmes studies have focussed on Aβ as therapeutic target. Active immunization and passive immunization against Aβ leads to the clearance of deposits in humans and transgenic mice expressing human Aβ but have failed to improve memory loss. This review will discuss the possible explanations for the lack of efficacy of Aβ immunotherapy, including the role of a pro-inflammatory response and subsequent vascular side effects, the binding site of therapeutic antibodies and the timing of the treatment. We further discuss how antibodies can be engineered for improved efficacy.
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Affiliation(s)
- Isabelle L Sumner
- Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Ross A Edwards
- Biological Sciences, University of Southampton, Southampton, United Kingdom
| | | | - Jessica L Teeling
- Biological Sciences, University of Southampton, Southampton, United Kingdom
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22
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Kehoe PG, Hibbs E, Palmer LE, Miners JS. Angiotensin-III is Increased in Alzheimer's Disease in Association with Amyloid-β and Tau Pathology. J Alzheimers Dis 2018; 58:203-214. [PMID: 28387670 DOI: 10.3233/jad-161265] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Hyperactivity of the renin-angiotensin system (RAS) is associated with the pathogenesis of Alzheimer's disease (AD) believed to be mediated by angiotensin-II (Ang-II) activation of the angiotensin type 1 receptor (AT1R). We previously showed that angiotensin-converting enzyme-1 (ACE-1) activity, the rate-limiting enzyme in the production of Ang-II, is increased in human postmortem brain tissue in AD. Angiotensin-III (Ang-III) activates the AT1R and angiotensin type-2 receptor (AT2R), but its potential role in the pathophysiology of AD remains unexplored. We measured Ang-II and Ang-III levels by ELISA, and the levels and activities of aminopeptidase-A (AP-A) and aminopeptidase-N (AP-N) (responsible for the production and metabolism of Ang-III, respectively) in human postmortem brain tissue in the mid-frontal cortex (Brodmann area 9) in a cohort of AD (n = 90) and age-matched non-demented controls (n = 59), for which we had previous measurements of ACE-1 activity, Aβ level, and tau pathology (also in the mid-frontal cortex). We found that both Ang-II and Ang-III levels were significantly higher in AD compared to age-matched controls and that Ang-III, rather than Ang-II, was strongly associated with Aβ load and tau load. Levels of AP-A were significantly reduced in AD but AP-A enzyme activity was unchanged whereas AP-N activity was reduced in AD but AP-N protein level was unchanged. Together, these data indicate that the APA/Ang-III/APN/Ang-IV/AT4R pathway is dysregulated and that elevated Ang-III could contribute to the pathogenesis of AD.
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23
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Kumar K, Kumar A, Keegan RM, Deshmukh R. Recent advances in the neurobiology and neuropharmacology of Alzheimer’s disease. Biomed Pharmacother 2018; 98:297-307. [DOI: 10.1016/j.biopha.2017.12.053] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 12/03/2017] [Accepted: 12/13/2017] [Indexed: 01/24/2023] Open
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24
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Wirths O, Walter S, Kraus I, Klafki HW, Stazi M, Oberstein TJ, Ghiso J, Wiltfang J, Bayer TA, Weggen S. N-truncated Aβ 4-x peptides in sporadic Alzheimer's disease cases and transgenic Alzheimer mouse models. ALZHEIMERS RESEARCH & THERAPY 2017; 9:80. [PMID: 28978359 PMCID: PMC5628465 DOI: 10.1186/s13195-017-0309-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/11/2017] [Indexed: 01/03/2023]
Abstract
Background The deposition of neurotoxic amyloid-β (Aβ) peptides in plaques in the brain parenchyma and in cerebral blood vessels is considered to be a key event in Alzheimer’s disease (AD) pathogenesis. Although the presence and impact of full-length Aβ peptides such as Aβ1–40 and Aβ1–42 have been analyzed extensively, the deposition of N-terminally truncated Aβ peptide species has received much less attention, largely because of the lack of specific antibodies. Methods This paper describes the generation and characterization of novel antibodies selective for Aβ4–x peptides and provides immunohistochemical evidence of Aβ4–x in the human brain and its distribution in the APP/PS1KI and 5XFAD transgenic mouse models. Results The Aβ4–x staining pattern was restricted mainly to amyloid plaque cores and cerebral amyloid angiopathy in AD and Down syndrome cases and in both AD mouse models. In contrast, diffuse amyloid deposits were largely negative for Aβ4–x immunoreactivity. No overt intraneuronal staining was observed. Conclusions The findings of this study are consistent with previous reports demonstrating a high aggregation propensity of Aβ4–x peptides and suggest an important role of these N-truncated Aβ species in the process of amyloidogenesis and plaque core formation. Electronic supplementary material The online version of this article (doi:10.1186/s13195-017-0309-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Oliver Wirths
- Division of Molecular Psychiatry, University Medical Center (UMG), Georg-August-University, von-Siebold-Strasse 5, 37075, Goettingen, Germany. .,Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, von-Siebold-Strasse 5, 37075, Goettingen, Germany.
| | - Susanne Walter
- Department of Neuropathology, Heinrich-Heine-University, Düsseldorf, Germany
| | - Inga Kraus
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, von-Siebold-Strasse 5, 37075, Goettingen, Germany
| | - Hans W Klafki
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, von-Siebold-Strasse 5, 37075, Goettingen, Germany
| | - Martina Stazi
- Division of Molecular Psychiatry, University Medical Center (UMG), Georg-August-University, von-Siebold-Strasse 5, 37075, Goettingen, Germany.,Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, von-Siebold-Strasse 5, 37075, Goettingen, Germany
| | - Timo J Oberstein
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen, Germany
| | - Jorge Ghiso
- Department of Pathology, New York University School of Medicine, New York, NY, USA.,Departments of Psychiatry, New York University School of Medicine, New York, NY, USA
| | - Jens Wiltfang
- Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, von-Siebold-Strasse 5, 37075, Goettingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany.,Institute for Research in Biomedicine (iBiMED), Medical Sciences Department, University of Aveiro, Aveiro, Portugal
| | - Thomas A Bayer
- Division of Molecular Psychiatry, University Medical Center (UMG), Georg-August-University, von-Siebold-Strasse 5, 37075, Goettingen, Germany.,Department of Psychiatry and Psychotherapy, University Medical Center (UMG), Georg-August-University, von-Siebold-Strasse 5, 37075, Goettingen, Germany
| | - Sascha Weggen
- Department of Neuropathology, Heinrich-Heine-University, Düsseldorf, Germany
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25
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Hullmann M, Albrecht C, van Berlo D, Gerlofs-Nijland ME, Wahle T, Boots AW, Krutmann J, Cassee FR, Bayer TA, Schins RPF. Diesel engine exhaust accelerates plaque formation in a mouse model of Alzheimer's disease. Part Fibre Toxicol 2017; 14:35. [PMID: 28854940 PMCID: PMC5577845 DOI: 10.1186/s12989-017-0213-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 08/16/2017] [Indexed: 11/24/2022] Open
Abstract
Background Increasing evidence from toxicological and epidemiological studies indicates that the central nervous system is an important target for ambient air pollutants. We have investigated whether long-term inhalation exposure to diesel engine exhaust (DEE), a dominant contributor to particulate air pollution in urban environments, can aggravate Alzheimer’s Disease (AD)-like effects in female 5X Familial AD (5XFAD) mice and their wild-type female littermates. Following 3 and 13 weeks exposures to diluted DEE (0.95 mg/m3, 6 h/day, 5 days/week) or clean air (controls) behaviour tests were performed and amyloid-β (Aβ) plaque formation, pulmonary histopathology and systemic inflammation were evaluated. Results In a string suspension task, assessing for grip strength and motor coordination, 13 weeks exposed 5XFAD mice performed significantly less than the 5XFAD controls. Spatial working memory deficits, assessed by Y-maze and X-maze tasks, were not observed in association with the DEE exposures. Brains of the 3 weeks DEE-exposed 5XFAD mice showed significantly higher cortical Aβ plaque load and higher whole brain homogenate Aβ42 levels than the clean air-exposed 5XFAD littermate controls. After the 13 weeks exposures, with increasing age and progression of the AD-phenotype of the 5XFAD mice, DEE-related differences in amyloid pathology were no longer present. Immunohistochemical evaluation of lungs of the mice revealed no obvious genetic background-related differences in tissue structure, and the DEE exposure did not cause histopathological changes in the mice of both backgrounds. Luminex analysis of plasma cytokines demonstrated absence of sustained systemic inflammation upon DEE exposure. Conclusions Inhalation exposure to DEE causes accelerated plaque formation and motor function impairment in 5XFAD transgenic mice. Our study provides further support that the brain is a relevant target for the effects of inhaled DEE and suggests that long-term exposure to this ubiquitous air pollution mixture may promote the development of Alzheimer’s disease.
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Affiliation(s)
- Maja Hullmann
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany
| | - Catrin Albrecht
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany
| | - Damiën van Berlo
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany.,, Present address: Triskelion BV Utrechtseweg 48, 3704 HE, Zeist, The Netherlands
| | | | - Tina Wahle
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany
| | - Agnes W Boots
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany.,Department of Pharmacology and Toxicology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Jean Krutmann
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany.,Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Flemming R Cassee
- National Institute for Public Health and the Environment, Bilthoven, The Netherlands.,Institute of Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
| | - Thomas A Bayer
- Department of Psychiatry and Psychotherapy, Division of Molecular Psychiatry, Georg-August-University Göttingen, University Medicine Göttingen, Göttingen, Germany
| | - Roel P F Schins
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Düsseldorf, Germany.
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26
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Aβ truncated species: Implications for brain clearance mechanisms and amyloid plaque deposition. Biochim Biophys Acta Mol Basis Dis 2017; 1864:208-225. [PMID: 28711595 DOI: 10.1016/j.bbadis.2017.07.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 06/24/2017] [Accepted: 07/11/2017] [Indexed: 12/14/2022]
Abstract
Extensive parenchymal and vascular Aβ deposits are pathological hallmarks of Alzheimer's disease (AD). Besides classic full-length peptides, biochemical analyses of brain deposits have revealed high degree of Aβ heterogeneity likely resulting from the action of multiple proteolytic enzymes. In spite of the numerous studies focusing in Aβ, the relevance of N- and C-terminal truncated species for AD pathogenesis remains largely understudied. In the present work, using novel antibodies specifically recognizing Aβ species N-terminally truncated at position 4 or C-terminally truncated at position 34, we provide a clear assessment of the differential topographic localization of these species in AD brains and transgenic models. Based on their distinct solubility, brain N- and C-terminal truncated species were extracted by differential fractionation and identified via immunoprecipitation coupled to mass spectrometry analysis. Biochemical/biophysical studies with synthetic homologues further confirmed the different solubility properties and contrasting fibrillogenic characteristics of the truncated species composing the brain Aβ peptidome. Aβ C-terminal degradation leads to the production of more soluble fragments likely to be more easily eliminated from the brain. On the contrary, N-terminal truncation at position 4 favors the formation of poorly soluble, aggregation prone peptides with high amyloidogenic propensity and the potential to exacerbate the fibrillar deposits, self-perpetuating the amyloidogenic loop. Detailed assessment of the molecular diversity of Aβ species composing interstitial fluid and amyloid deposits at different disease stages, as well as the evaluation of the truncation profile during various pharmacologic approaches will provide a comprehensive understanding of the still undefined contribution of Aβ truncations to the disease pathogenesis and their potential as novel therapeutic targets.
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27
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Lyons B, Friedrich M, Raftery M, Truscott R. Amyloid Plaque in the Human Brain Can Decompose from Aβ(1-40/1-42) by Spontaneous Nonenzymatic Processes. Anal Chem 2016; 88:2675-84. [DOI: 10.1021/acs.analchem.5b03891] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Brian Lyons
- Illawarra
Health and Medical Research Institute, University of Wollongong, Northfields
Avenue, Wollongong, New South
Wales 2522, Australia
- Save
Sight Institute, Sydney Eye Hospital, University of Sydney, 8 Macquarie
Street, Sydney, New South
Wales 2001, Australia
| | - Michael Friedrich
- Illawarra
Health and Medical Research Institute, University of Wollongong, Northfields
Avenue, Wollongong, New South
Wales 2522, Australia
| | - Mark Raftery
- Biological
Mass Spectrometry Facility, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Roger Truscott
- Illawarra
Health and Medical Research Institute, University of Wollongong, Northfields
Avenue, Wollongong, New South
Wales 2522, Australia
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28
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Immunotherapy Against N-Truncated Amyloid-β Oligomers. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2016. [DOI: 10.1007/978-1-4939-3560-4_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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29
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Alzheimer therapy with an antibody against N-terminal Abeta 4-X and pyroglutamate Abeta 3-X. Sci Rep 2015; 5:17338. [PMID: 26626428 PMCID: PMC4667289 DOI: 10.1038/srep17338] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 10/28/2015] [Indexed: 11/28/2022] Open
Abstract
Full-length Aβ1-42 and Aβ1-40, N-truncated pyroglutamate Aβ3-42 and Aβ4-42 are major variants in the Alzheimer brain. Aβ4-42 has not been considered as a therapeutic target yet. We demonstrate that the antibody NT4X and its Fab fragment reacting with both the free N-terminus of Aβ4-x and pyroglutamate Aβ3-X mitigated neuron loss in Tg4-42 mice expressing Aβ4-42 and completely rescued spatial reference memory deficits after passive immunization. NT4X and its Fab fragment also rescued working memory deficits in wild type mice induced by intraventricular injection of Aβ4-42. NT4X reduced pyroglutamate Aβ3-x, Aβx-40 and Thioflavin-S positive plaque load after passive immunization of 5XFAD mice. Aβ1-x and Aβx-42 plaque deposits were unchanged. Importantly, for the first time, we demonstrate that passive immunization using the antibody NT4X is therapeutically beneficial in Alzheimer mouse models showing that N-truncated Aβ starting with position four in addition to pyroglutamate Aβ3-x is a relevant target to fight Alzheimer’s disease.
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Bouter Y, Lopez Noguerola JS, Tucholla P, Crespi GAN, Parker MW, Wiltfang J, Miles LA, Bayer TA. Abeta targets of the biosimilar antibodies of Bapineuzumab, Crenezumab, Solanezumab in comparison to an antibody against N‑truncated Abeta in sporadic Alzheimer disease cases and mouse models. Acta Neuropathol 2015; 130:713-29. [PMID: 26467270 DOI: 10.1007/s00401-015-1489-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/05/2015] [Accepted: 10/05/2015] [Indexed: 01/01/2023]
Abstract
Solanezumab and Crenezumab are two humanized antibodies targeting Amyloid-β (Aβ) which are currently tested in multiple clinical trials for the prevention of Alzheimer's disease. However, there is a scientific discussion ongoing about the target engagement of these antibodies. Here, we report the immunohistochemical staining profiles of biosimilar antibodies of Solanezumab, Crenezumab and Bapineuzumab in human formalin-fixed, paraffin-embedded tissue and human fresh frozen tissue. Furthermore, we performed a direct comparative immunohistochemistry analysis of the biosimilar versions of the humanized antibodies in different mouse models including 5XFAD, Tg4-42, TBA42, APP/PS1KI, 3xTg. The staining pattern with these humanized antibodies revealed a surprisingly similar profile. All three antibodies detected plaques, cerebral amyloid angiopathy and intraneuronal Aβ in a similar fashion. Remarkably, Solanezumab showed a strong binding affinity to plaques. We also reaffirmed that Bapineuzumab does not recognize N-truncated or modified Aβ, while Solanezumab and Crenezumab do detect N-terminally modified Aβ peptides Aβ4-42 and pyroglutamate Aβ3-42. In addition, we compared the results with the staining pattern of the mouse NT4X antibody that recognizes specifically Aβ4-42 and pyroglutamate Aβ3-42, but not full-length Aβ1-42. In contrast to the biosimilar antibodies of Solanezumab, Crenezumab and Bapineuzumab, the murine NT4X antibody shows a unique target engagement. NT4X does barely cross-react with amyloid plaques in human tissue. It does, however, detect cerebral amyloid angiopathy in human tissue. In Alzheimer mouse models, NT4X detects intraneuronal Aβ and plaques comparable to the humanized antibodies. In conclusion, the biosimilar antibodies Solanezumab, Crenezumab and Bapineuzumab strongly react with amyloid plaques, which are in contrast to the NT4X antibody that hardly recognizes plaques in human tissue. Therefore, NT4X is the first of a new class of therapeutic antibodies.
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Luccarini I, Grossi C, Rigacci S, Coppi E, Pugliese AM, Pantano D, la Marca G, Ed Dami T, Berti A, Stefani M, Casamenti F. Oleuropein aglycone protects against pyroglutamylated-3 amyloid-ß toxicity: biochemical, epigenetic and functional correlates. Neurobiol Aging 2014; 36:648-63. [PMID: 25293421 DOI: 10.1016/j.neurobiolaging.2014.08.029] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 08/01/2014] [Accepted: 08/28/2014] [Indexed: 01/12/2023]
Abstract
Amyloid-ß (Aß) fragments, oligomeric Aß aggregates, and pyroglutamylated-Aß peptides, as well as epigenetic mechanisms and autophagy dysfunction all appear to contribute in various ways to Alzheimer's disease progression. We previously showed that dietary supplementation of oleuropein aglycone, a natural phenol abundant in the extra virgin olive oil, can be protective by reducing Aß42 deposits in the brain of young and middle-aged TgCRND8 mice. Here, we extended our study to aged TgCRND8 mice showing increased pE3-Aß in the brain deposits. We report that oleuropein aglycone is active against glutaminylcyclase-catalyzed pE3-Aß generation reducing enzyme expression and interferes both with Aß42 and pE3-Aß aggregation. Moreover, the phenol astonishingly activates neuronal autophagy even in mice at advanced stage of pathology, where it increases histone 3 and 4 acetylation, which matches both a decrease of histone deacetylase 2 expression and a significant improvement of synaptic function. The occurrence of these functional, epigenetic, and histopathologic beneficial effects even at a late stage of the pathology suggests that the phenol could be beneficial at the therapeutic, in addition to the prevention, level.
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Affiliation(s)
- Ilaria Luccarini
- Department of Neuroscience, Psychology, Drug Research and Child Health, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Cristina Grossi
- Department of Neuroscience, Psychology, Drug Research and Child Health, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Stefania Rigacci
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Elisabetta Coppi
- Department of Health Sciences, University of Florence, Florence, Italy
| | - Anna Maria Pugliese
- Department of Neuroscience, Psychology, Drug Research and Child Health, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Daniela Pantano
- Department of Neuroscience, Psychology, Drug Research and Child Health, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Giancarlo la Marca
- Department of Neuroscience, Psychology, Drug Research and Child Health, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy; Department of NEUROFARBA, Newborn Screening, Clinical Chemistry and Pharmacology Lab, Meyer Children's University Hospital, Florence, Italy
| | - Teresa Ed Dami
- Department of Neuroscience, Psychology, Drug Research and Child Health, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy; Department of NEUROFARBA, Newborn Screening, Clinical Chemistry and Pharmacology Lab, Meyer Children's University Hospital, Florence, Italy
| | - Andrea Berti
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Massimo Stefani
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Fiorella Casamenti
- Department of Neuroscience, Psychology, Drug Research and Child Health, Division of Pharmacology and Toxicology, University of Florence, Florence, Italy.
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Schneider F, Baldauf K, Wetzel W, Reymann KG. Behavioral and EEG changes in male 5xFAD mice. Physiol Behav 2014; 135:25-33. [PMID: 24907698 DOI: 10.1016/j.physbeh.2014.05.041] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 04/23/2014] [Accepted: 05/28/2014] [Indexed: 11/18/2022]
Abstract
Transgenic animal models of Alzheimer's disease (AD) are widely used to investigate mechanisms of pathophysiology and cognitive dysfunctions. A model with a very early development of parenchymal plaque load at the age of 2months is the 5xFAD mouse (Tg6799, Oakley et al. 2006). These 5xFAD mice over-express both human amyloid precursor protein (APP) and human presenilin 1 (PS1). Mice from this line have a high APP expression correlating with a high burden and an accelerated accumulation of the 42 amino acid species of amyloid-β (Aβ). The aim of this study was the behavioral and functional investigations of 5xFAD males because in most studies females of this strain were characterized. In comparison to literature of transgenic 5xFAD females, transgenic 5xFAD males showed decreased anxiety in the elevated plus maze, reduced locomotion and exploration in the open field and disturbances in learning performance in the Morris water maze starting at 9months of age. Electroencephalogram (EEG) recordings on 6month old transgenic mice revealed a decrease of delta, theta, alpha, beta and gamma frequency bands whereas the subdelta frequency was increased. EEG recordings during sleep showed a reduction of rapid eye movement sleep in relation to the amount of total sleep. Thus, 5xFAD males develop early functional disturbances and subsequently behavioral deficits and therefore they are a good mouse model for studying Alzheimer's disease.
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Affiliation(s)
- F Schneider
- German Centre for Neurodegenerative Diseases (DZNE), D-39120 Magdeburg, Germany.
| | - K Baldauf
- German Centre for Neurodegenerative Diseases (DZNE), D-39120 Magdeburg, Germany.
| | - W Wetzel
- Leibniz Institute for Neurobiology, Brenneckestr. 6, D-39118 Magdeburg, Germany.
| | - K G Reymann
- German Centre for Neurodegenerative Diseases (DZNE), D-39120 Magdeburg, Germany; Leibniz Institute for Neurobiology, Brenneckestr. 6, D-39118 Magdeburg, Germany.
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Focusing the amyloid cascade hypothesis on N-truncated Abeta peptides as drug targets against Alzheimer's disease. Acta Neuropathol 2014; 127:787-801. [PMID: 24803226 PMCID: PMC4024135 DOI: 10.1007/s00401-014-1287-x] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 04/25/2014] [Accepted: 04/25/2014] [Indexed: 02/07/2023]
Abstract
Although N-truncated Aβ variants are known to be the main constituent of amyloid plaques in the brains of patients with Alzheimer’s disease, their potential as targets for pharmacological intervention has only recently been investigated. In the last few years, the Alzheimer field has experienced a paradigm shift with the ever increasing understanding that targeting amyloid plaques has not led to a successful immunotherapy. On the other hand, there can be no doubt that the amyloid cascade hypothesis is central to the etiology of Alzheimer’s disease, raising the question as to why it is apparently failing to translate into the clinic. In this review, we aim to refocus the amyloid hypothesis integrating N-truncated Aβ peptides based on mounting evidence that they may represent better targets than full-length Aβ. In addition to Aβ peptides starting with an Asp at position 1, a variety of different N-truncated Aβ peptides have been identified starting with amino residue Ala-2, pyroglutamylated Glu-3, Phe-4, Arg-5, His-6, Asp-7, Ser-8, Gly-9, Tyr-10 and pyroglutamylated Glu-11. Certain forms of N-truncated species are better correlates for early pathological changes found pre-symptomatically more often than others. There is also evidence that, together with full-length Aβ, they might be physiologically detectable and are naturally secreted by neurons. Others are known to form soluble aggregates, which have neurotoxic properties in transgenic mouse models. It has been clearly demonstrated by several groups that some N-truncated Aβs dominate full-length Aβ in the brains of Alzheimer’s patients. We try to address which of the N-truncated variants may be promising therapeutic targets and which enzymes might be involved in the generation of these peptides
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Abundance of Aβ₅-x like immunoreactivity in transgenic 5XFAD, APP/PS1KI and 3xTG mice, sporadic and familial Alzheimer's disease. Mol Neurodegener 2014; 9:13. [PMID: 24694184 PMCID: PMC3975588 DOI: 10.1186/1750-1326-9-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 03/28/2014] [Indexed: 01/23/2023] Open
Abstract
Background According to the modified amyloid hypothesis the main event in the pathogenesis of Alzheimer’s disease (AD) is the deposition of neurotoxic amyloid β-peptide (Aβ) within neurons. Additionally to full-length peptides, a great diversity of N-truncated Aβ variants is derived from the larger amyloid precursor protein (APP). Vast evidence suggests that Aβx-42 isoforms play an important role triggering neurodegeneration due to its high abundance, amyloidogenic propensity and toxicity. Although N-truncated and Aβx-42 species have been pointed as crucial players in AD etiology, the Aβ5-x isoforms have not received much attention. Results The present study is the first to show immunohistochemical evidence of Aβ5-x in familial cases of AD (FAD) and its distribution in APP/PS1KI, 5XFAD and 3xTG transgenic mouse models. In order to probe Aβ5-x peptides we generated the AB5-3 antibody. Positive plaques and congophilic amyloid angiopathy (CAA) were observed among all the FAD cases tested carrying either APP or presenilin 1 (PS1) mutations and most of the sporadic cases of AD (SAD). Different patterns of Aβ5-x distribution were found in the mouse models carrying different combinations of autosomal mutations in the APP, PS1 and Tau genes. All of them showed extracellular Aβ deposits but none CAA. Additionally, they were all affected by a severe amyloid pathology in the hippocampus among other areas. Interestingly, neither 5XFAD nor APP/PS1KI showed any evidence for intraneuronal Aβ5-x. Conclusions Different degrees of Aβ5-x accumulations can be found in the transgenic AD mouse models and human cases expressing the sporadic or the familial form of the disease. Due to the lack of intracellular Aβ5-x, these isoforms might not be contributing to early mechanisms in the cascade of events triggering AD pathology. Brain sections obtained from SAD cases showed higher Aβ5-x–immunoreactivity in vascular deposits than in extracellular plaques, while both are equally important in the FAD cases. The difference may rely on alternative mechanisms involving Aβ5-x peptides and operating in a divergent way in the late and early onset forms of the disease.
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