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Insoluble Vascular Amyloid Deposits Trigger Disruption of the Neurovascular Unit in Alzheimer's Disease Brains. Int J Mol Sci 2021; 22:ijms22073654. [PMID: 33915754 PMCID: PMC8036769 DOI: 10.3390/ijms22073654] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 12/19/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease, characterized histopathologically by intra-neuronal tau-related lesions and by the accumulation of amyloid β-peptide (Aβ) in the brain parenchyma and around cerebral blood vessels. According to the vascular hypothesis of AD, an alteration in the neurovascular unit (NVU) could lead to Aβ vascular accumulation and promote neuronal dysfunction, accelerating neurodegeneration and dementia. To date, the effects of insoluble vascular Aβ deposits on the NVU and the blood-brain barrier (BBB) are unknown. In this study, we analyze different Aβ species and their association with the cells that make up the NVU. We evaluated post-mortem AD brain tissue. Multiple immunofluorescence assays were performed against different species of Aβ and the main elements that constitute the NVU. Our results showed that there are insoluble vascular deposits of both full-length and truncated Aβ species. Besides, insoluble aggregates are associated with a decrease in the phenotype of the cellular components that constitute the NVU and with BBB disruption. This approach could help identify new therapeutic targets against key molecules and receptors in the NVU that can prevent the accumulation of vascular fibrillar Aβ in AD.
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Zhao J, Shi Q, Zheng Y, Liu Q, He Z, Gao Z, Liu Q. Insights Into the Mechanism of Tyrosine Nitration in Preventing β-Amyloid Aggregation in Alzheimer's Disease. Front Mol Neurosci 2021; 14:619836. [PMID: 33658911 PMCID: PMC7917295 DOI: 10.3389/fnmol.2021.619836] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 01/20/2021] [Indexed: 01/30/2023] Open
Abstract
Nitration of tyrosine at the tenth residue (Tyr10) in amyloid-β (Aβ) has been reported to reduce its aggregation and neurotoxicity in our previous studies. However, the exact mechanism remains unclear. Here, we used Aβ1-42 peptide with differently modified forms at Tyr10 to investigate the molecular mechanism to fill this gap. By using immunofluorescent assay, we confirmed that nitrated Aβ was found in the cortex of 10-month-old female triple transgenic mice of Alzheimer's disease (AD). And then, we used the surface-enhanced Raman scattering (SERS) method and circular dichroism (CD) to demonstrate that the modification and mutation of Tyr10 in Aβ have little impact on conformational changes. Then, with the aids of fluorescence assays of thioflavin T and 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid, transmission electron microscopy (TEM), atomic force microscopy (AFM), and dynamic light scattering (DLS), we found that adding a large group to the phenolic ring of Tyr10 of Aβ could not inhibit Aβ fibrilization and aggregation. Nitration of Aβ reduces its aggregation mainly because it could induce the deprotonation of the phenolic hydroxyl group of Tyr10 of Aβ at physiological pH. We proposed that the negatively charged Tyr10 caused by nitration at physiological pH could interact with the salt bridge between Glu11 and His6 or His13 and block the kink around Tyr10, thereby preventing Aβ fibrilization and aggregation. These findings provide us new insights into the relationship between Tyr10 nitration and Aβ aggregation, which would help to further understand that keeping the balance of nitric oxide in vivo is important for preventing AD.
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Affiliation(s)
- Jie Zhao
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Sciences, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.,Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, China
| | - Qihui Shi
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Sciences, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Ye Zheng
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Sciences, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Qiulian Liu
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Sciences, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Zhijun He
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Sciences, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Zhonghong Gao
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Qiong Liu
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Sciences, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.,Shenzhen Bay Laboratory, Shenzhen, China
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Gunn AP, Wong BX, McLean C, Fowler C, Barnard PJ, Duce JA, Roberts BR. Increased glutaminyl cyclase activity in brains of Alzheimer's disease individuals. J Neurochem 2020; 156:979-987. [PMID: 32614980 DOI: 10.1111/jnc.15114] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/27/2020] [Accepted: 06/24/2020] [Indexed: 12/23/2022]
Abstract
Glutaminyl cyclases (QC) catalyze the formation of neurotoxic pGlu-modified amyloid-β peptides found in the brains of people with Alzheimer's disease (AD). Reports of several-fold increases in soluble QC (sQC) expression in the brain and peripheral circulation of AD individuals has prompted the development of QC inhibitors as potential AD therapeutics. There is, however, a lack of standardized quantitative data on QC expression in human tissues, precluding inter-laboratory comparison and validation. We tested the hypothesis that QC is elevated in AD tissues by quantifying levels of sQC protein and activity in post-mortem brain tissues from AD and age-matched control individuals. We found a modest but statistically significant increase in sQC protein, which paralleled a similar increase in enzyme activity. In plasma samples sourced from the Australian Imaging, Biomarker and Lifestyle study we determined that QC activity was not different between the AD and control group, though a modest increase was observed in female AD individuals compared to controls. Plasma QC activity was further correlated with levels of circulating monocytes in AD individuals. These data provide quantitative evidence that alterations in QC expression are associated with AD pathology.
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Affiliation(s)
- Adam P Gunn
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Vic, Australia.,Analytical Chemistry, Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
| | - Bruce X Wong
- The ALBORADA Drug Discovery Institute, University of Cambridge, Cambridge, UK
| | - Catriona McLean
- Department of Anatomical Pathology, Alfred Hospital, Prahran, Vic, Australia
| | - Chris Fowler
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Vic, Australia
| | - Peter J Barnard
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Vic, Australia
| | - James A Duce
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Vic, Australia.,The ALBORADA Drug Discovery Institute, University of Cambridge, Cambridge, UK
| | - Blaine R Roberts
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Vic, Australia.,Department of Biochemistry, Emory School of Medicine, Atlanta, GA, USA.,Department of Neurology, Emory School of Medicine, Atlanta, GA, USA
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Hu ZW, Vugmeyster L, Au DF, Ostrovsky D, Sun Y, Qiang W. Molecular structure of an N-terminal phosphorylated β-amyloid fibril. Proc Natl Acad Sci U S A 2019; 116:11253-11258. [PMID: 31097588 PMCID: PMC6561245 DOI: 10.1073/pnas.1818530116] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The structural polymorphism in β-amyloid (Aβ) plaques from Alzheimer disease (AD) has been recognized as an important pathological factor. Plaques from sporadic AD patients contain fibrillar deposits of various amyloid proteins/peptides, including posttranslational modified Aβ (PTM-Aβ) subtypes. Although many PTM-Aβs were shown to accelerate the fibrillation process, increase neuronal cytotoxicity of aggregates, or enhance the stability of fibrils, the contribution of PTM-Aβs to structural polymorphisms and their pathological roles remains unclear. We report here the NMR-based structure for the Ser-8-phosphorylated 40-residue Aβ (pS8-Aβ40) fibrils, which shows significant difference to the wild-type fibrils, with higher cross-seeding efficiency and thermodynamic stability. Given these physicochemical properties, the structures originated from pS8-Aβ40 fibrils may potentially dominate the polymorphisms in the mixture of wild-type and phosphorylated Aβ deposits. Our results imply that Aβ subtypes with "seeding-prone" properties may influence the polymorphisms of amyloid plaques through the cross-seeding process.
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Affiliation(s)
- Zhi-Wen Hu
- Department of Chemistry, Binghamton University, Binghamton, NY 13902
| | - Liliya Vugmeyster
- Department of Chemistry, University of Colorado Denver, Denver, CO 80204;
| | - Dan Fai Au
- Department of Chemistry, University of Colorado Denver, Denver, CO 80204
| | - Dmitry Ostrovsky
- Department of Mathematics, University of Colorado Denver, Denver, CO 80204
| | - Yan Sun
- Health Science Core Facility, Small Scale System Integration and Packaging Center, Binghamton University, Binghamton, NY 13902
| | - Wei Qiang
- Department of Chemistry, Binghamton University, Binghamton, NY 13902;
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Plant-based chimeric HPV-virus-like particles bearing amyloid-β epitopes elicit antibodies able to recognize amyloid plaques in APP-tg mouse and Alzheimer’s disease brains. Inflammopharmacology 2017; 26:817-827. [DOI: 10.1007/s10787-017-0408-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 10/11/2017] [Indexed: 10/18/2022]
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Perez-Garmendia R, Gevorkian G. Pyroglutamate-Modified Amyloid Beta Peptides: Emerging Targets for Alzheimer´s Disease Immunotherapy. Curr Neuropharmacol 2014; 11:491-8. [PMID: 24403873 PMCID: PMC3763757 DOI: 10.2174/1570159x11311050004] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 03/16/2013] [Accepted: 03/28/2013] [Indexed: 12/25/2022] Open
Abstract
Extracellular and intraneuronal accumulation of amyloid-beta (Aβ) peptide aggregates in the brain has been hypothesized to play an important role in the neuropathology of Alzheimer’s Disease (AD). The main Aβ variants detected in the human brain are Aβ1-40 and Aβ1-42, however a significant proportion of AD brain Aβ consists also of N-terminal truncated species. Pyroglutamate-modified Aβ peptides have been demonstrated to be the predominant components among all N-terminal truncated Aβ species in AD brains and represent highly desirable and abundant therapeutic targets. The current review describes the properties and localization of two pyroglutamate-modified Aβ peptides, AβN3(pE) and AβN11(pE), in the brain. The role of glutaminyl cyclase (QC) in the formation of these peptides is also addressed. In addition, two potential therapeutic strategies, the inhibition of QC and immunotherapy approaches, and clinical trials aimed to target these important pathological Aβ species are reviewed.
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Affiliation(s)
- Roxanna Perez-Garmendia
- Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico (UNAM), Mexico DF, Mexico
| | - Goar Gevorkian
- Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico (UNAM), Mexico DF, Mexico
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Hernandez-Zimbron LF, Luna-Muñoz J, Mena R, Vazquez-Ramirez R, Kubli-Garfias C, Cribbs DH, Manoutcharian K, Gevorkian G. Amyloid-β peptide binds to cytochrome C oxidase subunit 1. PLoS One 2012; 7:e42344. [PMID: 22927926 PMCID: PMC3424232 DOI: 10.1371/journal.pone.0042344] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 07/03/2012] [Indexed: 11/24/2022] Open
Abstract
Extracellular and intraneuronal accumulation of amyloid-beta aggregates has been demonstrated to be involved in the pathogenesis of Alzheimer's disease (AD). However, the precise mechanism of amyloid-beta neurotoxicity is not completely understood. Previous studies suggest that binding of amyloid-beta to a number of macromolecules has deleterious effects on cellular functions. Mitochondria were found to be the target for amyloid-beta, and mitochondrial dysfunction is well documented in AD. In the present study we have shown for the first time that Aβ 1–42 bound to a peptide comprising the amino-terminal region of cytochrome c oxidase subunit 1. Phage clone, selected after screening of a human brain cDNA library expressed on M13 phage and bearing a 61 amino acid fragment of cytochrome c oxidase subunit 1, bound to Aβ 1–42 in ELISA as well as to Aβ aggregates present in AD brain. Aβ 1–42 and cytochrome c oxidase subunit 1 co-immunoprecipitated from mitochondrial fraction of differentiated human neuroblastoma cells. Likewise, molecular dynamics simulation of the cytochrome c oxidase subunit 1 and the Aβ 1–42 peptide complex resulted in a reliable helix-helix interaction, supporting the experimental results. The interaction between Aβ 1–42 and cytochrome c oxidase subunit 1 may explain, in part, the diminished enzymatic activity of respiratory chain complex IV and subsequent neuronal metabolic dysfunction observed in AD.
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Affiliation(s)
| | - Jose Luna-Muñoz
- Department of Neurosciences, CINVESTAV-IPN, Mexico DF, Mexico
| | - Raul Mena
- Department of Neurosciences, CINVESTAV-IPN, Mexico DF, Mexico
| | - Ricardo Vazquez-Ramirez
- Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico (UNAM), Mexico DF, Mexico
| | - Carlos Kubli-Garfias
- Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico (UNAM), Mexico DF, Mexico
| | - David H. Cribbs
- Institute for Memory Impairments and Neurological Disorders, University of California Irvine, Irvine, California, United States of America
- Department of Neurology, University of California Irvine, Irvine, California, United States of America
| | - Karen Manoutcharian
- Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico (UNAM), Mexico DF, Mexico
| | - Goar Gevorkian
- Instituto de Investigaciones Biomedicas, Universidad Nacional Autonoma de Mexico (UNAM), Mexico DF, Mexico
- * E-mail:
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Lane RF, Shineman DW, Steele JW, Lee LBH, Fillit HM. Beyond amyloid: the future of therapeutics for Alzheimer's disease. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2012; 64:213-71. [PMID: 22840749 DOI: 10.1016/b978-0-12-394816-8.00007-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Currently, the field is awaiting the results of several pivotal Phase III clinical Alzheimer's disease (AD) trials that target amyloid-β (Aβ). In light of the recent biomarker studies that indicate Aβ levels are at their most dynamic 5-10 years before the onset of clinical symptoms, it is becoming uncertain whether direct approaches to target Aβ will achieve desired clinical efficacy. AD is a complex neurodegenerative disease caused by dysregulation of numerous neurobiological networks and cellular functions, resulting in synaptic loss, neuronal loss, and ultimately impaired memory. While it is clear that Aβ plays a key role in the pathogenesis of AD, it may be a challenging and inefficient target for mid-to-late stage AD intervention. Throughout the course of AD, multiple pathways become perturbed, presenting a multitude of possible therapeutic avenues for design of AD intervention and prophylactic therapies. In this chapter, we sought to first provide an overview of Aβ-directed strategies that are currently in development, and the pivotal Aβ-targeted trials that are currently underway. Next, we delve into the biology and therapeutic designs associated with other key areas of research in the field including tau, protein trafficking and degradation pathways, ApoE, synaptic function, neurotrophic/neuroprotective strategies, and inflammation and energy utilization. For each area we have provided a comprehensive and balanced overview of the therapeutic strategies currently in preclinical and clinical development, which will shape the future therapeutic landscape of AD.
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Affiliation(s)
- Rachel F Lane
- Alzheimer's Drug Discovery Foundation, New York, NY, USA
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Pyroglutamate-Aβ 3 and 11 colocalize in amyloid plaques in Alzheimer's disease cerebral cortex with pyroglutamate-Aβ 11 forming the central core. Neurosci Lett 2011; 505:109-12. [PMID: 22001577 DOI: 10.1016/j.neulet.2011.09.071] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 09/21/2011] [Accepted: 09/30/2011] [Indexed: 10/16/2022]
Abstract
N-terminal truncated amyloid beta (Aβ) derivatives, especially the forms having pyroglutamate at the 3 position (AβpE3) or at the 11 position (AβpE11) have become the topic of considerable study. AβpE3 is known to make up a substantial portion of the Aβ species in senile plaques while AβpE11 has received less attention. We have generated very specific polyclonal antibodies against both species. Each antibody recognizes only the antigen against which it was generated on Western blots and neither recognizes full length Aβ. Both anti-AβpE3 and anti-AβpE11 stain senile plaques specifically in Alzheimer's disease cerebral cortex and colocalize with Aβ, as shown by confocal microscopy. In a majority of plaques examined, AβpE11 was observed to be the dominant form in the innermost core. These data suggest that AβpE11 may serve as a generating site for senile plaque formation.
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