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Islam MR, Rabbi MA, Hossain T, Sultana S, Uddin S. Mechanistic Approach to Immunity and Immunotherapy of Alzheimer's Disease: A Review. ACS Chem Neurosci 2024. [PMID: 39173186 DOI: 10.1021/acschemneuro.4c00360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2024] Open
Abstract
Alzheimer's disease (AD) is a debilitating neurodegenerative condition characterized by progressive cognitive decline and memory loss, affecting millions of people worldwide. Traditional treatments, such as cholinesterase inhibitors and NMDA receptor antagonists, offer limited symptomatic relief without addressing the underlying disease mechanisms. These limitations have driven the development of more potent and effective therapies. Recent advances in immunotherapy present promising avenues for AD treatment. Immunotherapy strategies, including both active and passive approaches, harness the immune system to target and mitigate AD-related pathology. Active immunotherapy stimulates the patient's immune response to produce antibodies against AD-specific antigens, while passive immunotherapy involves administering preformed antibodies or immune cells that specifically target amyloid-β (Aβ) or tau proteins. Monoclonal antibodies, such as aducanumab and lecanemab, have shown potential in reducing Aβ plaques and slowing cognitive decline in clinical trials, despite challenges related to adverse immune responses and the need for precise targeting. This comprehensive review explores the role of the immune system in AD, evaluates the current successes and limitations of immunotherapeutic approaches, and discusses future directions for enhancing the treatment efficacy.
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Affiliation(s)
- Md Rubiath Islam
- Department of Biochemistry and Molecular Biology, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
| | - Md Afser Rabbi
- Department of Biochemistry and Molecular Biology, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
| | - Tanbir Hossain
- Department of Biochemistry and Molecular Biology, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
| | - Sadia Sultana
- Department of Biochemistry and Molecular Biology, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
| | - Shihab Uddin
- Department of Bioengineering, King Fahad University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia
- Interdisciplinary Research Center for Bio Systems and Machines, King Fahad University of Petroleum & Minerals, Dhahran-31261, Saudi Arabia
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Żukowska J, Moss SJ, Subramanian V, Acharya KR. Molecular basis of selective amyloid-β degrading enzymes in Alzheimer's disease. FEBS J 2024; 291:2999-3029. [PMID: 37622248 DOI: 10.1111/febs.16939] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/31/2023] [Accepted: 08/22/2023] [Indexed: 08/26/2023]
Abstract
The accumulation of the small 42-residue long peptide amyloid-β (Aβ) has been proposed as a major trigger for the development of Alzheimer's disease (AD). Within the brain, the concentration of Aβ peptide is tightly controlled through production and clearance mechanisms. Substantial experimental evidence now shows that reduced levels of Aβ clearance are present in individuals living with AD. This accumulation of Aβ can lead to the formation of large aggregated amyloid plaques-one of two detectable hallmarks of the disease. Aβ-degrading enzymes (ADEs) are major players in the clearance of Aβ. Stimulating ADE activity or expression, in order to compensate for the decreased clearance in the AD phenotype, provides a promising therapeutic target. It has been reported in mice that upregulation of ADEs can reduce the levels of Aβ peptide and amyloid plaques-in some cases, this led to improved cognitive function. Among several known ADEs, neprilysin (NEP), endothelin-converting enzyme-1 (ECE-1), insulin degrading enzyme (IDE) and angiotensin-1 converting enzyme (ACE) from the zinc metalloprotease family have been identified as important. These ADEs have the capacity to digest soluble Aβ which, in turn, cannot form the toxic oligomeric species. While they are known for their amyloid degradation, they exhibit complexity through promiscuous nature and a broad range of substrates that they can degrade. This review highlights current structural and functional understanding of these key ADEs, giving some insight into the molecular interactions that leads to the hydrolysis of peptide substrates, the crucial tasks performed by them and the potential for therapeutic use in the future.
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3
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Terron HM, Parikh SJ, Abdul-Hay SO, Sahara T, Kang D, Dickson DW, Saftig P, LaFerla FM, Lane S, Leissring MA. Prominent tauopathy and intracellular β-amyloid accumulation triggered by genetic deletion of cathepsin D: implications for Alzheimer disease pathogenesis. Alzheimers Res Ther 2024; 16:70. [PMID: 38575959 PMCID: PMC10996108 DOI: 10.1186/s13195-024-01443-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 03/31/2024] [Indexed: 04/06/2024]
Abstract
BACKGROUND Cathepsin D (CatD) is a lysosomal protease that degrades both the amyloid-β protein (Aβ) and the microtubule-associated protein, tau, which accumulate pathognomonically in Alzheimer disease (AD), but few studies have examined the role of CatD in the development of Aβ pathology and tauopathy in vivo. METHODS CatD knockout (KO) mice were crossed to human amyloid precursor protein (hAPP) transgenic mice, and amyloid burden was quantified by ELISA and immunohistochemistry (IHC). Tauopathy in CatD-KO mice, as initially suggested by Gallyas silver staining, was further characterized by extensive IHC and biochemical analyses. Controls included human tau transgenic mice (JNPL3) and another mouse model of a disease (Krabbe A) characterized by pronounced lysosomal dysfunction. Additional experiments examined the effects of CatD inhibition on tau catabolism in vitro and in cultured neuroblastoma cells with inducible expression of human tau. RESULTS Deletion of CatD in hAPP transgenic mice triggers large increases in cerebral Aβ, manifesting as intense, exclusively intracellular aggregates; extracellular Aβ deposition, by contrast, is neither triggered by CatD deletion, nor affected in older, haploinsufficient mice. Unexpectedly, CatD-KO mice were found to develop prominent tauopathy by just ∼ 3 weeks of age, accumulating sarkosyl-insoluble, hyperphosphorylated tau exceeding the pathology present in aged JNPL3 mice. CatD-KO mice exhibit pronounced perinuclear Gallyas silver staining reminiscent of mature neurofibrillary tangles in human AD, together with widespread phospho-tau immunoreactivity. Striking increases in sarkosyl-insoluble phospho-tau (∼ 1250%) are present in CatD-KO mice but notably absent from Krabbe A mice collected at an identical antemortem interval. In vitro and in cultured cells, we show that tau catabolism is slowed by blockade of CatD proteolytic activity, including via competitive inhibition by Aβ42. CONCLUSIONS Our findings support a major role for CatD in the proteostasis of both Aβ and tau in vivo. To our knowledge, the CatD-KO mouse line is the only model to develop detectable Aβ accumulation and profound tauopathy in the absence of overexpression of hAPP or human tau with disease-associated mutations. Given that tauopathy emerges from disruption of CatD, which can itself be potently inhibited by Aβ42, our findings suggest that impaired CatD activity may represent a key mechanism linking amyloid accumulation and tauopathy in AD.
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Affiliation(s)
- Heather M Terron
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine (UCI MIND), Irvine, CA, 92697, USA
| | - Sagar J Parikh
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine (UCI MIND), Irvine, CA, 92697, USA
| | - Samer O Abdul-Hay
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Tomoko Sahara
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Dongcheul Kang
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Paul Saftig
- Institut für Biochemie, Christian-Albrechts-Universität zu Kiel, D-24098, Kiel, Germany
| | - Frank M LaFerla
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine (UCI MIND), Irvine, CA, 92697, USA
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, 92697, USA
| | - Shelley Lane
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine (UCI MIND), Irvine, CA, 92697, USA
| | - Malcolm A Leissring
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine (UCI MIND), Irvine, CA, 92697, USA.
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA.
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Rodrigo AP, Moutinho Cabral I, Alexandre A, Costa PM. Exploration of Toxins from a Marine Annelid: An Analysis of Phyllotoxins and Accompanying Bioactives. Animals (Basel) 2024; 14:635. [PMID: 38396603 PMCID: PMC10885894 DOI: 10.3390/ani14040635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/09/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024] Open
Abstract
Proteinaceous toxins are peptides or proteins that hold great biotechnological value, evidenced by their ecological role, whether as defense or predation mechanisms. Bioprospecting using bioinformatics and omics may render screening for novel bioactives more expeditious, especially considering the immense diversity of toxin-secreting marine organisms. Eulalia sp. (Annelida: Phyllodocidae), a toxin bearing marine annelid, was recently shown to secrete cysteine-rich protein (Crisp) toxins (hitherto referred to as 'phyllotoxins') that can immobilize its prey. By analyzing and validating transcriptomic data, we narrowed the list of isolated full coding sequences of transcripts of the most abundant toxins or accompanying bioactives secreted by the species (the phyllotoxin Crisp, hyaluronidase, serine protease, and peptidases M12A, M13, and M12B). Through homology matching with human proteins, the biotechnological potential of the marine annelid's toxins and related proteins was tentatively associated with coagulative and anti-inflammatory responses for the peptidases PepM12A, SePr, PepM12B, and PepM13, and with the neurotoxic activity of Crisp, and finally, hyaluronidase was inferred to bear properties of an permeabilizing agent. The in silico analysis succeeded by validation by PCR and Sanger sequencing enabled us to retrieve cDNAs can may be used for the heterologous expression of these toxins.
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Affiliation(s)
- Ana P. Rodrigo
- Associate Laboratory i4HB Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University of Lisbon, 2829-516 Caparica, Portugal; (I.M.C.); (A.A.)
- UCIBIO Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University of Lisbon, 2829-516 Caparica, Portugal
| | - Inês Moutinho Cabral
- Associate Laboratory i4HB Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University of Lisbon, 2829-516 Caparica, Portugal; (I.M.C.); (A.A.)
- UCIBIO Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University of Lisbon, 2829-516 Caparica, Portugal
| | - António Alexandre
- Associate Laboratory i4HB Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University of Lisbon, 2829-516 Caparica, Portugal; (I.M.C.); (A.A.)
- UCIBIO Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University of Lisbon, 2829-516 Caparica, Portugal
| | - Pedro M. Costa
- Associate Laboratory i4HB Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University of Lisbon, 2829-516 Caparica, Portugal; (I.M.C.); (A.A.)
- UCIBIO Applied Molecular Biosciences Unit, Department of Life Sciences, NOVA School of Science and Technology, NOVA University of Lisbon, 2829-516 Caparica, Portugal
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Eckman EA, Clausen DM, Solé-Domėnech S, Lee CW, Sinobas-Pereira C, Domalewski RJ, Nichols MR, Pacheco-Quinto J. Nascent Aβ42 Fibrillization in Synaptic Endosomes Precedes Plaque Formation in a Mouse Model of Alzheimer's-like β-Amyloidosis. J Neurosci 2023; 43:8812-8824. [PMID: 37884349 PMCID: PMC10727180 DOI: 10.1523/jneurosci.1318-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 10/05/2023] [Accepted: 10/23/2023] [Indexed: 10/28/2023] Open
Abstract
Accumulation of amyloid-β peptide (Aβ) aggregates in synapses may contribute to the profound synaptic loss characteristic of Alzheimer's disease (AD). The origin of synaptic Aβ aggregates remains elusive, but loss of endosomal proteostasis may trigger their formation. In this study, we identified the synaptic compartments where Aβ accumulates, and performed a longitudinal analysis of synaptosomes isolated from brains of TgCRND8 APP transgenic mice of either sex. To evaluate the specific contribution of Aβ-degrading protease endothelin-converting enzyme (ECE-1) to synaptic/endosomal Aβ homeostasis, we analyzed the effect of partial Ece1 KO in brain and complete ECE1 KO in SH-SY5Y cells. Global inhibition of ECE family members was used to further assess their role in preventing synaptic Aβ accumulation. Results showed that, before extracellular amyloid deposition, synapses were burdened with detergent-soluble Aβ monomers, oligomers, and fibrils. Levels of all soluble Aβ species declined thereafter, as Aβ42 turned progressively insoluble and accumulated in Aβ-producing synaptic endosomal vesicles with characteristics of multivesicular bodies. Accordingly, fibrillar Aβ was detected in brain exosomes. ECE-1-deficient mice had significantly increased endogenous synaptosomal Aβ42 levels, and protease inhibitor experiments showed that, in TgCRND8 mice, synaptic Aβ42 became nearly resistant to degradation by ECE-related proteases. Our study supports that Aβ accumulating in synapses is produced locally, within endosomes, and does not require the presence of amyloid plaques. ECE-1 is a determinant factor controlling the accumulation and fibrillization of nascent Aβ in endosomes and, in TgCRND8 mice, Aβ overproduction causes rapid loss of Aβ42 solubility that curtails ECE-mediated degradation.SIGNIFICANCE STATEMENT Deposition of aggregated Aβ in extracellular plaques is a defining feature of AD. Aβ aggregates also accumulate in synapses and may contribute to the profound synaptic loss and cognitive dysfunction typical of the disease. However, it is not clear whether synaptotoxic Aβ is mainly derived from plaques or if it is produced and aggregated locally, within affected synaptic compartments. Filling this knowledge gap is important for the development of an effective treatment for AD, as extracellular and intrasynaptic pools of Aβ may not be equally modulated by immunotherapies or other therapeutic approaches. In this manuscript, we provide evidence that Aβ aggregates building up in synapses are formed locally, within synaptic endosomes, because of disruptions in nascent Aβ proteostasis.
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Affiliation(s)
- Elizabeth A Eckman
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey 07927
| | - Dana M Clausen
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey 07927
| | | | - Chris W Lee
- Biomedical Research Institute of New Jersey, Cedar Knolls, New Jersey 07927
| | - Cristina Sinobas-Pereira
- Department of Chemistry & Biochemistry, University of Missouri-St. Louis, St. Louis, Missouri 63121
| | - Ryan J Domalewski
- Department of Chemistry & Biochemistry, University of Missouri-St. Louis, St. Louis, Missouri 63121
| | - Michael R Nichols
- Department of Chemistry & Biochemistry, University of Missouri-St. Louis, St. Louis, Missouri 63121
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Rowland H, Moxon S, Corbett N, Hanson K, Fisher K, Kellett K, Hooper N. Inhibition of insulin-degrading enzyme in human neurons promotes amyloid-β deposition. Neuronal Signal 2023; 7:NS20230016. [PMID: 37808160 PMCID: PMC10550784 DOI: 10.1042/ns20230016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 10/10/2023] Open
Abstract
Alzheimer's disease (AD) is characterised by the aggregation and deposition of amyloid-β (Aβ) peptides in the human brain. In age-related late-onset AD, deficient degradation and clearance, rather than enhanced production, of Aβ contributes to disease pathology. In the present study, we assessed the contribution of the two key Aβ-degrading zinc metalloproteases, insulin-degrading enzyme (IDE) and neprilysin (NEP), to Aβ degradation in human induced pluripotent stem cell (iPSC)-derived cortical neurons. Using an Aβ fluorescence polarisation assay, inhibition of IDE but not of NEP, blocked the degradation of Aβ by human neurons. When the neurons were grown in a 3D extracellular matrix to visualise Aβ deposition, inhibition of IDE but not NEP, increased the number of Aβ deposits. The resulting Aβ deposits were stained with the conformation-dependent, anti-amyloid antibodies A11 and OC that recognise Aβ aggregates in the human AD brain. Inhibition of the Aβ-forming β-secretase prevented the formation of the IDE-inhibited Aβ deposits. These data indicate that inhibition of IDE in live human neurons grown in a 3D matrix increased the deposition of Aβ derived from the proteolytic cleavage of the amyloid precursor protein. This work has implications for strategies aimed at enhancing IDE activity to promote Aβ degradation in AD.
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Affiliation(s)
- Helen A. Rowland
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, M13 9PT, Manchester, U.K
| | - Samuel R. Moxon
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, M13 9PT, Manchester, U.K
| | - Nicola J. Corbett
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, M13 9PT, Manchester, U.K
| | - Kelsey Hanson
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, M13 9PT, Manchester, U.K
| | - Kate Fisher
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, M13 9PT, Manchester, U.K
| | - Katherine A.B. Kellett
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, M13 9PT, Manchester, U.K
| | - Nigel M. Hooper
- Division of Neuroscience, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, M13 9PT, Manchester, U.K
- Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance and University of Manchester, Manchester, U.K
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Terron HM, Parikh SJ, Abdul-Hay SO, Sahara T, Kang D, Dickson DW, Saftig P, LaFerla FM, Lane S, Leissring MA. Prominent tauopathy and intracellular β-amyloid accumulation triggered by genetic deletion of cathepsin D: Implications for Alzheimer disease pathogenesis. RESEARCH SQUARE 2023:rs.3.rs-3464352. [PMID: 37961253 PMCID: PMC10635349 DOI: 10.21203/rs.3.rs-3464352/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Background Cathepsin D (CatD) is a lysosomal protease that degrades both the amyloid-β protein (Aβ) and the microtubule-associated protein, tau, which accumulate pathognomonically in Alzheimer disease (AD), but few studies have examined the role of CatD in the development of Aβ pathology and tauopathy in vivo. Methods CatD knockout (KO) mice were crossed to human amyloid precursor protein (hAPP) transgenic mice, and amyloid burden was quantified by ELISA and immunohistochemistry (IHC). Tauopathy in CatD-KO mice, as initially suggested by Gallyas silver staining, was further characterized by extensive IHC and biochemical analyses. Controls included human tau transgenic mice (JNPL3) and another mouse model characterized by pronounced lysosomal dysfunction (Krabbe A). Additional experiments examined the effects of CatD inhibition on tau catabolism in vitro and in cultured neuroblastoma cells with inducible expression of human tau. Results Deletion of CatD in hAPP transgenic mice triggers large increases in cerebral Aβ, manifesting as intense, exclusively intracellular aggregates; extracellular Aβ deposition, by contrast, is neither triggered by CatD deletion, nor affected in older, haploinsufficient mice. Unexpectedly, CatDKO mice were found to develop prominent tauopathy by just ~ 3 weeks of age, accumulating sarkosyl-insoluble, hyperphosphorylated tau exceeding the pathology in aged JNPL3 mice. CatDKO mice exhibit pronounced perinuclear Gallyas silver staining reminiscent of mature neurofibrillary tangles in human AD, together with widespread phospho-tau immunoreactivity. Striking increases in sarkosyl-insoluble phospho-tau (~ 1250%) are present in CatD-KO mice, but notably absent from Krabbe A mice collected at an identical antemortem interval. In vitro and in cultured cells, we show that tau catabolism is slowed by blockade of CatD proteolytic activity, including via competitive inhibition by Aβ42. Conclusions Our findings support a major role for CatD in the proteostasis of both Aβ and tau in vivo. To our knowledge, CatD-KO mice are the only model to develop detectable Aβ acumulation and profound tauopathy in the absence of overexpression of hAPP or human tau with disease-associated mutations. Given that tauopathy emerges from disruption of CatD, which can itself be potently inhibited by Aβ42, our findings suggest that impaired CatD activity may represent a key mechanism linking amyloid accumulation and tauopathy in AD.
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Gutierrez-Merino C. Brain Hydrophobic Peptides Antagonists of Neurotoxic Amyloid β Peptide Monomers/Oligomers-Protein Interactions. Int J Mol Sci 2023; 24:13846. [PMID: 37762148 PMCID: PMC10531495 DOI: 10.3390/ijms241813846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/02/2023] [Accepted: 09/05/2023] [Indexed: 09/29/2023] Open
Abstract
Amyloid β (Aβ) oligomers have been linked to Alzheimer's disease (AD) pathogenesis and are the main neurotoxic forms of Aβ. This review focuses on the following: (i) the Aβ(1-42):calmodulin interface as a model for the design of antagonist Aβ peptides and its limitations; (ii) proteolytic degradation as the major source of highly hydrophobic peptides in brain cells; and (iii) brain peptides that have been experimentally demonstrated to bind to Aβ monomers or oligomers, Aβ fibrils, or Aβ plaques. It is highlighted that the hydrophobic amino acid residues of the COOH-terminal segment of Aβ(1-42) play a key role in its interaction with intracellular protein partners linked to its neurotoxicity. The major source of highly hydrophobic endogenous peptides of 8-10 amino acids in neurons is the proteasome activity. Many canonical antigen peptides bound to the major histocompatibility complex class 1 are of this type. These highly hydrophobic peptides bind to Aβ and are likely to be efficient antagonists of the binding of Aβ monomers/oligomers concentrations in the nanomolar range with intracellular proteins. Also, their complexation with Aβ will protect them against endopeptidases, suggesting a putative chaperon-like physiological function for Aβ that has been overlooked until now. Remarkably, the hydrophobic amino acid residues of Aβ responsible for the binding of several neuropeptides partially overlap with those playing a key role in its interaction with intracellular protein partners that mediates its neurotoxicity. Therefore, these latter neuropeptides are also potential candidates to antagonize Aβ peptides binding to target proteins. In conclusion, the analysis performed in this review points out that hydrophobic endogenous brain neuropeptides could be valuable biomarkers to evaluate the risk of the onset of sporadic AD, as well as for the prognosis of AD.
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Affiliation(s)
- Carlos Gutierrez-Merino
- Instituto de Biomarcadores de Patologías Moleculares, Universidad de Extremadura, 06006 Badajoz, Spain
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Sun Z, Zhao C, Liu X, Zhang P, Wang X, Man X, Li Z, Du Y, Che X, Xiang Y. Mutation analysis of the ECE1 gene in late-onset Alzheimer's disease. Neurobiol Aging 2023; 129:58-61. [PMID: 37271044 DOI: 10.1016/j.neurobiolaging.2023.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 04/22/2023] [Accepted: 05/02/2023] [Indexed: 06/06/2023]
Abstract
We recently identified a rare coding mutation (R186C) in the ECE2 gene in a late-onset AD (LOAD) family, and demonstrated ECE2 is a risk gene for AD development. ECE1 is a homologous enzyme that shares catalytic activity with ECE2. Although ECE1 has been regarded as a potential candidate gene for AD, few studies have investigated the role of ECE1 variants in patients with AD. In this study, we aimed to investigate rare variants in ECE1 in a cohort of 610 patients with LOAD (age of onset ≥65 years). The summary data of ECE1 variants from ChinaMAP database were used as controls (n = 10,588). We found four rare variants (p.R50W, p.A166=, p.R650Q, and p.P751=) in the patients with sporadic LOAD, while we identified a large number of controls carrying rare variants in ECE1. Moreover, there was no significant association between LOAD and non-synonymous rare damaging variants at the gene level. Our results suggest rare coding variants of ECE1 might not play an important role in AD risk in the Chinese population.
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Affiliation(s)
- Zhanfang Sun
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Cheng Zhao
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Xueming Liu
- Department of Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Shandong University, Jinan, China
| | - Peng Zhang
- iCarbonX (Zhuhai) Company Limited, Shenzhen, China
| | - Xiang Wang
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Xiao Man
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Zhen Li
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Yifeng Du
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Xiangqian Che
- Department of Neurology & Neuroscience Institute, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Yuanyuan Xiang
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.
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Ullah R, Lee EJ. Advances in Amyloid-β Clearance in the Brain and Periphery: Implications for Neurodegenerative Diseases. Exp Neurobiol 2023; 32:216-246. [PMID: 37749925 PMCID: PMC10569141 DOI: 10.5607/en23014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/25/2023] [Accepted: 08/23/2023] [Indexed: 09/27/2023] Open
Abstract
This review examines the role of impaired amyloid-β clearance in the accumulation of amyloid-β in the brain and the periphery, which is closely associated with Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA). The molecular mechanism underlying amyloid-β accumulation is largely unknown, but recent evidence suggests that impaired amyloid-β clearance plays a critical role in its accumulation. The review provides an overview of recent research and proposes strategies for efficient amyloid-β clearance in both the brain and periphery. The clearance of amyloid-β can occur through enzymatic or non-enzymatic pathways in the brain, including neuronal and glial cells, blood-brain barrier, interstitial fluid bulk flow, perivascular drainage, and cerebrospinal fluid absorption-mediated pathways. In the periphery, various mechanisms, including peripheral organs, immunomodulation/immune cells, enzymes, amyloid-β-binding proteins, and amyloid-β-binding cells, are involved in amyloid-β clearance. Although recent findings have shed light on amyloid-β clearance in both regions, opportunities remain in areas where limited data is available. Therefore, future strategies that enhance amyloid-β clearance in the brain and/or periphery, either through central or peripheral clearance approaches or in combination, are highly encouraged. These strategies will provide new insight into the disease pathogenesis at the molecular level and explore new targets for inhibiting amyloid-β deposition, which is central to the pathogenesis of sporadic AD (amyloid-β in parenchyma) and CAA (amyloid-β in blood vessels).
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Affiliation(s)
- Rahat Ullah
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, School of Medicine, The Johns Hopkins University, Baltimore, MD 21205, USA
- Department of Neurology, School of Medicine, The Johns Hopkins University, Baltimore, MD 21205, USA
| | - Eun Jeong Lee
- Department of Brain Science, Ajou University School of Medicine, Suwon 16499, Korea
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Valverde-Salazar V, Ruiz-Gabarre D, García-Escudero V. Alzheimer's Disease and Green Tea: Epigallocatechin-3-Gallate as a Modulator of Inflammation and Oxidative Stress. Antioxidants (Basel) 2023; 12:1460. [PMID: 37507998 PMCID: PMC10376369 DOI: 10.3390/antiox12071460] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/05/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia, characterised by a marked decline of both memory and cognition, along with pathophysiological hallmarks including amyloid beta peptide (Aβ) accumulation, tau protein hyperphosphorylation, neuronal loss and inflammation in the brain. Additionally, oxidative stress caused by an imbalance between free radicals and antioxidants is considered one of the main risk factors for AD, since it can result in protein, lipid and nucleic acid damage and exacerbate Aβ and tau pathology. To date, there is a lack of successful pharmacological approaches to cure or even ameliorate the terrible impact of this disease. Due to this, dietary compounds with antioxidative and anti-inflammatory properties acquire special relevance as potential therapeutic agents. In this context, green tea, and its main bioactive compound, epigallocatechin-3-gallate (EGCG), have been targeted as a plausible option for the modulation of AD. Specifically, EGCG acts as an antioxidant by regulating inflammatory processes involved in neurodegeneration such as ferroptosis and microglia-induced cytotoxicity and by inducing signalling pathways related to neuronal survival. Furthermore, it reduces tau hyperphosphorylation and aggregation and promotes the non-amyloidogenic route of APP processing, thus preventing the formation of Aβ and its subsequent accumulation. Taken together, these results suggest that EGCG may be a suitable candidate in the search for potential therapeutic compounds for neurodegenerative disorders involving inflammation and oxidative stress, including Alzheimer's disease.
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Affiliation(s)
- Víctor Valverde-Salazar
- Department of Anatomy, Histology and Neuroscience, School of Medicine, Universidad Autónoma de Madrid, 28029 Madrid, Spain
| | - Daniel Ruiz-Gabarre
- Department of Anatomy, Histology and Neuroscience, School of Medicine, Universidad Autónoma de Madrid, 28029 Madrid, Spain
| | - Vega García-Escudero
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, CIBERNED, 28031 Madrid, Spain
- Institute for Molecular Biology-IUBM, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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12
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Yamamoto N, Tokumon T, Obuchi A, Kono M, Saigo K, Tanida M, Ikeda-Matsuo Y, Sobue K. Poly(I:C) promotes neurotoxic amyloid β accumulation through reduced degradation by decreasing neprilysin protein levels in astrocytes. J Neurochem 2022; 163:517-530. [PMID: 36321194 DOI: 10.1111/jnc.15716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 08/19/2022] [Accepted: 09/18/2022] [Indexed: 11/06/2022]
Abstract
Inflammation associated with viral infection of the nervous system has been involved in the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease (AD) and multiple sclerosis. Polyinosinic:polycytidylic acid (poly[I:C]) is a Toll-like receptor 3 (TLR3) agonist that mimics the inflammatory response to systemic viral infections. Despite growing recognition of the role of glial cells in AD pathology, their involvement in the accumulation and clearance of amyloid β (Aβ) in the brain of patients with AD is poorly understood. Neprilysin (NEP) and insulin-degrading enzyme (IDE) are the main Aβ-degrading enzymes in the brain. This study investigated whether poly(I:C) regulated Aβ degradation and neurotoxicity by modulating NEP and IDE protein levels through TLR3 in astrocytes. To this aim, primary rat primary astrocyte cultures were treated with poly(I:C) and inhibitors of the TLR3 signaling. Protein levels were assessed by Western blot. Aβ toxicity to primary neurons was measured by lactate dehydrogenase release. Poly(I:C) induced a significant decrease in NEP levels on the membrane of astrocytes as well as in the culture medium. The degradation of exogenous Aβ was markedly delayed in poly(I:C)-treated astrocytes. This delay significantly increased the neurotoxicity of exogenous Aβ1-42. Altogether, these results suggest that viral infections induce Aβ neurotoxicity by decreasing NEP levels in astrocytes and consequently preventing Aβ degradation.
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Affiliation(s)
- Naoki Yamamoto
- Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Himeji, Hyogo, Japan.,Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, Ishikawa, Japan
| | - Takuya Tokumon
- Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, Ishikawa, Japan
| | - Ayako Obuchi
- Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Himeji, Hyogo, Japan
| | - Mari Kono
- Scientific Research, Scientific Affairs, Sysmex Corporation, Kobe, Hyogo, Japan
| | - Katsuyasu Saigo
- Faculty of Nursing, Himeji Dokkyo University, Himeji, Hyogo, Japan
| | - Mamoru Tanida
- Department of Physiology II, Kanazawa Medical University, Uchinada, Ishikawa, Japan
| | - Yuri Ikeda-Matsuo
- Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, Ishikawa, Japan
| | - Kazuya Sobue
- Department of Anesthesiology and Intensive Care Medicine, Nagoya City University Graduate School of Medical Sciences, Nagoya City, Aichi, Japan
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13
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Rai M, Curley M, Coleman Z, Demontis F. Contribution of proteases to the hallmarks of aging and to age-related neurodegeneration. Aging Cell 2022; 21:e13603. [PMID: 35349763 PMCID: PMC9124314 DOI: 10.1111/acel.13603] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/10/2022] [Accepted: 03/13/2022] [Indexed: 12/20/2022] Open
Abstract
Protein quality control ensures the degradation of damaged and misfolded proteins. Derangement of proteostasis is a primary cause of aging and age-associated diseases. The ubiquitin-proteasome and autophagy-lysosome play key roles in proteostasis but, in addition to these systems, the human genome encodes for ~600 proteases, also known as peptidases. Here, we examine the role of proteases in aging and age-related neurodegeneration. Proteases are present across cell compartments, including the extracellular space, and their substrates encompass cellular constituents, proteins with signaling functions, and misfolded proteins. Proteolytic processing by proteases can lead to changes in the activity and localization of substrates or to their degradation. Proteases cooperate with the autophagy-lysosome and ubiquitin-proteasome systems but also have independent proteolytic roles that impact all hallmarks of cellular aging. Specifically, proteases regulate mitochondrial function, DNA damage repair, cellular senescence, nutrient sensing, stem cell properties and regeneration, protein quality control and stress responses, and intercellular signaling. The capacity of proteases to regulate cellular functions translates into important roles in preserving tissue homeostasis during aging. Consequently, proteases influence the onset and progression of age-related pathologies and are important determinants of health span. Specifically, we examine how certain proteases promote the progression of Alzheimer's, Huntington's, and/or Parkinson's disease whereas other proteases protect from neurodegeneration. Mechanistically, cleavage by proteases can lead to the degradation of a pathogenic protein and hence impede disease pathogenesis. Alternatively, proteases can generate substrate byproducts with increased toxicity, which promote disease progression. Altogether, these studies indicate the importance of proteases in aging and age-related neurodegeneration.
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Affiliation(s)
- Mamta Rai
- Department of Developmental NeurobiologySt. Jude Children’s Research HospitalMemphisTennesseeUSA
| | - Michelle Curley
- Department of Developmental NeurobiologySt. Jude Children’s Research HospitalMemphisTennesseeUSA
| | - Zane Coleman
- Department of Developmental NeurobiologySt. Jude Children’s Research HospitalMemphisTennesseeUSA
| | - Fabio Demontis
- Department of Developmental NeurobiologySt. Jude Children’s Research HospitalMemphisTennesseeUSA
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14
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Sovateltide Mediated Endothelin B Receptors Agonism and Curbing Neurological Disorders. Int J Mol Sci 2022; 23:ijms23063146. [PMID: 35328566 PMCID: PMC8955091 DOI: 10.3390/ijms23063146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/08/2022] [Accepted: 03/11/2022] [Indexed: 11/17/2022] Open
Abstract
Neurological/neurovascular disorders constitute the leading cause of disability and the second leading cause of death globally. Major neurological/neurovascular disorders or diseases include cerebral stroke, Alzheimer’s disease, spinal cord injury, neonatal hypoxic-ischemic encephalopathy, and others. Their pathophysiology is considered highly complex and is the main obstacle in developing any drugs for these diseases. In this review, we have described the endothelin system, its involvement in neurovascular disorders, the importance of endothelin B receptors (ETBRs) as a novel potential drug target, and its agonism by IRL-1620 (INN—sovateltide), which we are developing as a drug candidate for treating the above-mentioned neurological disorders/diseases. In addition, we have highlighted the results of our preclinical and clinical studies related to these diseases. The phase I safety and tolerability study of sovateltide has shown it as a safe and tolerable compound at therapeutic dosages. Furthermore, preclinical and clinical phase II studies have demonstrated the efficacy of sovateltide in treating acute ischemic stroke. It is under development as a first-in-class drug. In addition, efficacy studies in Alzheimer’s disease (AD), acute spinal cord injury, and neonatal hypoxic-ischemic encephalopathy (HIE) are ongoing. Successful completion of these studies will validate that ETBRs signaling can be an important target in developing drugs to treat neurological/neurovascular diseases.
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15
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Peng HB, Bukuroshi P, Durk MR, Grootendorst P, Yan X, Pan SR, de Lannoy IAM, Pang KS. Impact of age, hypercholesterolemia, and the vitamin D receptor on brain endogenous β-amyloid peptide accumulation in mice. Biopharm Drug Dispos 2021; 42:372-388. [PMID: 34219248 DOI: 10.1002/bdd.2297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 06/12/2021] [Accepted: 06/14/2021] [Indexed: 12/24/2022]
Abstract
Age, hypercholesterolemia, and vitamin D deficiency are risk factors that increase the brain accumulation of pathogenic β-amyloid peptides (40 and 42), precursors leading to Alzheimer's disease (AD) in humans. The relative changes accompanying aging, high cholesterol, and/or treatment of calcitriol, active vitamin D receptor (VDR) ligand, under normal physiology are unknown. We examined these relative changes in C57BL/6 mice of ages 2, 4-8, and more than 10 months old, which were fed a normal or high fat / high cholesterol diet and treated with calcitriol, active ligand of the vitamin D receptor (0 or 2.5 μg/kg ×4, intraperitoneally, every other day to elicit cholesterol lowering in liver). Aβ40 but not Aβ42 accumulation in brain and lower P-glycoprotein (P-gp) and neprilysin protein expressions for Aβ efflux and degradation, respectively, were found to be associated with aging. But there was no trend for BACE1 (β-secretase 1, a cholesterol-sensitive enzyme) toward Aβ synthesis with age. In response to calcitriol treatment, P-gp was elevated, mitigating partially the age-related changes. Although age-dependent decreasing trends in mRNA expression levels existed for Cyp46a1, the brain cholesterol processing enzyme, whose inhibition increases BACE1 and ApoE to facilitate microglia Aβ degradation, mRNA changes for other cholesterol transporters: Acat1 and Abca1, and brain cholesterol levels remained unchanged. There was no observable change in the mRNA expression of amyloid precursor protein (APP) and the influx (RAGE) and efflux (LRP1) transporters with respect to age, diet, or calcitriol treatment. Overall, aging poses as a risk factor contributing to Aβ accumulation in brain, and VDR-mediated P-gp activation partially alleviates the outcome.
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Affiliation(s)
- H Benson Peng
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Paola Bukuroshi
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Matthew R Durk
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Paul Grootendorst
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Xiaoyu Yan
- Department of Pharmacy, Chinese University of Hong Kong, Hong Kong, China
| | - Sophie R Pan
- InterVivo Solutions Inc., Mississauga, Ontario, Canada
| | | | - K Sandy Pang
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
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16
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Pyun JM, Kang MJ, Ryoo N, Suh J, Youn YC, Park YH, Kim S. Amyloid Metabolism and Amyloid-Targeting Blood-Based Biomarkers of Alzheimer's Disease. J Alzheimers Dis 2021; 75:685-696. [PMID: 32390633 DOI: 10.3233/jad-200104] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Amyloid-β (Aβ) is a key protein in Alzheimer's disease (AD) in that its accumulation induces complex pathological changes. Although there has been extensive research on the metabolism of Aβ in AD, new compelling results have recently emerged. Historically, the production and clearance of Aβ have been thought to originate in the central nervous system (CNS). However, recent evidence suggests that the production and clearance of Aβ can also occur in the peripheral system, and that the peripherally driven Aβ migrates to the CNS and induces amyloidopathy with subsequent AD pathologic changes in the brain. This concept implies that AD is not restricted to the CNS but is a systemic disease instead. As such, the development of blood-based biomarkers targeting Aβ is of great interest. Central and peripheral Aβ are both active contributors to the pathology of AD and interact bidirectionally. Measuring peripheral Aβ is not just observing the reflection of the residual Aβ removed from the CNS but also tracking the ongoing process of AD pathology. Additionally, blood-based biomarkers could be a more accessible tool in clinical and research settings. Through arduous research, several blood-based biomarker assays have demonstrated notable results. In this review, we describe the metabolism of Aβ and the amyloid-targeting blood-based biomarkers of AD.
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Affiliation(s)
- Jung-Min Pyun
- Department of Neurology, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Seongnam-si, Republic of Korea
| | - Min Ju Kang
- Department of Neurology, Veterans Medical Research Institute, Veterans Health Service Medical Center, Seoul, Republic of Korea
| | - Nayoung Ryoo
- Department of Neurology, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Seongnam-si, Republic of Korea
| | - Jeewon Suh
- Department of Neurology, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Seongnam-si, Republic of Korea
| | - Young Chul Youn
- Department of Neurology, Chung-Ang University Hospital, Seoul, Republic of Korea
| | - Young Ho Park
- Department of Neurology, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Seongnam-si, Republic of Korea
| | - SangYun Kim
- Department of Neurology, Seoul National University College of Medicine and Seoul National University Bundang Hospital, Seongnam-si, Republic of Korea
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17
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Bang M, Gonzales EL, Shin CY, Kwon KJ. Late Passage Cultivation Induces Aged Astrocyte Phenotypes in Rat Primary Cultured Cells. Biomol Ther (Seoul) 2021; 29:144-153. [PMID: 33262320 PMCID: PMC7921865 DOI: 10.4062/biomolther.2020.175] [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: 10/06/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 11/10/2022] Open
Abstract
Astrocytes play various important roles such as maintaining brain homeostasis, supporting neurons, and secreting inflammatory mediators to protect the brain cells. In aged subjects, astrocytes show diversely changed phenotypes and dysfunctions. But, the study of aged astrocytes or astrocytes from aged subjects is not yet sufficient to provide a comprehensive understanding of their important processes in the regulation of brain function. In this study, we induced an in vitro aged astrocyte model through late passage cultivation of rat primary cultured astrocytes. Astrocytes were cultured until passage 7 (P7) as late passage astrocytes and compared with passage 1 (P1) astrocytes as early passage astrocytes to confirm the differences in phenotypes and the effects of serial passage. In this study, we confirmed the morphological, molecular, and functional changes of late passage astrocytes showing aging phenotypes through SA-β-gal staining and measurement of nuclear size. We also observed a reduced expression of inflammatory mediators including IL-1β, IL-6, TNFα, iNOS, and COX2, as well as dysregulation of wound-healing, phagocytosis, and mitochondrial functions such as mitochondrial membrane potential and mitochondrial oxygen consumption rate. Culture-conditioned media obtained from P1 astrocytes promoted neurite outgrowth in immature primary cultures of rat cortices, which is significantly reduced when we treated the immature neurons with the culture media obtained from P7 astrocytes. These results suggest that late passage astrocytes show senescent astrocyte phenotypes with functional defects, which makes it a suitable model for the study of the role of astrocyte senescence on the modulation of normal and pathological brain aging.
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Affiliation(s)
- Minji Bang
- Department of Neuroscience, School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul 05029, Republic of Korea
| | - Edson Luck Gonzales
- Department of Neuroscience, School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul 05029, Republic of Korea
| | - Chan Young Shin
- Department of Neuroscience, School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul 05029, Republic of Korea
| | - Kyoung Ja Kwon
- Department of Neuroscience, School of Medicine and Center for Neuroscience Research, Konkuk University, Seoul 05029, Republic of Korea
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18
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Ennerfelt HE, Lukens JR. The role of innate immunity in Alzheimer's disease. Immunol Rev 2020; 297:225-246. [PMID: 32588460 PMCID: PMC7783860 DOI: 10.1111/imr.12896] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/23/2020] [Accepted: 05/28/2020] [Indexed: 12/12/2022]
Abstract
The amyloid hypothesis has dominated Alzheimer's disease (AD) research for almost 30 years. This hypothesis hinges on the predominant clinical role of the amyloid beta (Aβ) peptide in propagating neurofibrillary tangles (NFTs) and eventual cognitive impairment in AD. Recent research in the AD field has identified the brain-resident macrophages, known as microglia, and their receptors as integral regulators of both the initiation and propagation of inflammation, Aβ accumulation, neuronal loss, and memory decline in AD. Emerging studies have also begun to reveal critical roles for distinct innate immune pathways in AD pathogenesis, which has led to great interest in harnessing the innate immune response as a therapeutic strategy to treat AD. In this review, we will highlight recent advancements in our understanding of innate immunity and inflammation in AD onset and progression. Additionally, there has been mounting evidence suggesting pivotal contributions of environmental factors and lifestyle choices in AD pathogenesis. Therefore, we will also discuss recent findings, suggesting that many of these AD risk factors influence AD progression via modulation of microglia and immune responses.
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Affiliation(s)
- Hannah E. Ennerfelt
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA 22908, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22908, USA
- Cell and Molecular Biology Training Program, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - John R. Lukens
- Center for Brain Immunology and Glia (BIG), Department of Neuroscience, University of Virginia, Charlottesville, VA 22908, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22908, USA
- Cell and Molecular Biology Training Program, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
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19
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Suire CN, Abdul-Hay SO, Sahara T, Kang D, Brizuela MK, Saftig P, Dickson DW, Rosenberry TL, Leissring MA. Cathepsin D regulates cerebral Aβ42/40 ratios via differential degradation of Aβ42 and Aβ40. ALZHEIMERS RESEARCH & THERAPY 2020; 12:80. [PMID: 32631408 PMCID: PMC7339583 DOI: 10.1186/s13195-020-00649-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/24/2020] [Indexed: 11/10/2022]
Abstract
BACKGROUND Cathepsin D (CatD) is a lysosomal protease that degrades both the amyloid β-protein (Aβ) and the microtubule-associated protein, tau, and has been genetically linked to late-onset Alzheimer disease (AD). Here, we sought to examine the consequences of genetic deletion of CatD on Aβ proteostasis in vivo and to more completely characterize the degradation of Aβ42 and Aβ40 by CatD. METHODS We quantified Aβ degradation rates and levels of endogenous Aβ42 and Aβ40 in the brains of CatD-null (CatD-KO), heterozygous null (CatD-HET), and wild-type (WT) control mice. CatD-KO mice die by ~ 4 weeks of age, so tissues from younger mice, as well as embryonic neuronal cultures, were investigated. Enzymological assays and surface plasmon resonance were employed to quantify the kinetic parameters (KM, kcat) of CatD-mediated degradation of monomeric human Aβ42 vs. Aβ40, and the degradation of aggregated Aβ42 species was also characterized. Competitive inhibition assays were used to interrogate the relative inhibition of full-length human and mouse Aβ42 and Aβ40, as well as corresponding p3 fragments. RESULTS Genetic deletion of CatD resulted in 3- to 4-fold increases in insoluble, endogenous cerebral Aβ42 and Aβ40, exceeding the increases produced by deletion of an insulin-degrading enzyme, neprilysin or both, together with readily detectable intralysosomal deposits of endogenous Aβ42-all by 3 weeks of age. Quite significantly, CatD-KO mice exhibited ~ 30% increases in Aβ42/40 ratios, comparable to those induced by presenilin mutations. Mechanistically, the perturbed Aβ42/40 ratios were attributable to pronounced differences in the kinetics of degradation of Aβ42 vis-à-vis Aβ40. Specifically, Aβ42 shows a low-nanomolar affinity for CatD, along with an exceptionally slow turnover rate that, together, renders Aβ42 a highly potent competitive inhibitor of CatD. Notably, the marked differences in the processing of Aβ42 vs. Aβ40 also extend to p3 fragments ending at positions 42 vs. 40. CONCLUSIONS Our findings identify CatD as the principal intracellular Aβ-degrading protease identified to date, one that regulates Aβ42/40 ratios via differential degradation of Aβ42 vs. Aβ40. The finding that Aβ42 is a potent competitive inhibitor of CatD suggests a possible mechanistic link between elevations in Aβ42 and downstream pathological sequelae in AD.
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Affiliation(s)
- Caitlin N Suire
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, 92697, USA.,Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, 92697, USA
| | - Samer O Abdul-Hay
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Tomoko Sahara
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Dongcheul Kang
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | - Monica K Brizuela
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, 92697, USA
| | - Paul Saftig
- Institut für Biochemie, Christian-Albrechts-Universität zu Kiel, 24098, Kiel, Germany
| | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA
| | | | - Malcolm A Leissring
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, 92697, USA. .,Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, 32224, USA.
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20
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Protein kinases A and C regulate amyloid-β degradation by modulating protein levels of neprilysin and insulin-degrading enzyme in astrocytes. Neurosci Res 2020; 166:62-72. [PMID: 32512031 DOI: 10.1016/j.neures.2020.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/02/2020] [Accepted: 05/21/2020] [Indexed: 12/24/2022]
Abstract
The pathology of sporadic Alzheimer's disease is hallmarked by altered signal transduction via the neurotransmitter receptor-G-protein-mediated protein kinase A (PKA) and protein kinase C (PKC) pathways. Because the accumulation of amyloid-β (Aβ) depends on its rates of synthesis and clearance, the metabolic pathway of Aβ in the brain and the entire body warrants exploration. The two major enzymes involved in Aβ degradation in the brain are believed to be the neprilysin and insulin-degrading enzyme (IDE). This study investigated whether PKA and PKC regulate the degradation of Aβ by modulating the protein levels of neprilysin and IDE in astrocytes. Activation of PKA induced a significant decrease in neprilysin protein levels in cultured astrocytes, whereas activation of PKC induced a significant decrease in the protein level of neprilysin and an increase in the protein level of IDE. Following activation of PKC, the reduction of neprilysin was achieved by its secretion into the culture media. Moreover, PKA-activated astrocytes significantly delayed the degradation of exogenous Aβ, whereas PKC-activated astrocytes significantly facilitated its degradation. These results suggest that PKA and PKC regulate Aβ degradation in astrocytes through a decrease in the protein level of neprilysin and an increase in neprilysin secretion and protein levels of IDE, respectively.
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21
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Liao X, Cai F, Sun Z, Zhang Y, Wang J, Jiao B, Guo J, Li J, Liu X, Guo L, Zhou Y, Wang J, Yan X, Jiang H, Xia K, Li J, Tang B, Shen L, Song W. Identification of Alzheimer's disease-associated rare coding variants in the ECE2 gene. JCI Insight 2020; 5:135119. [PMID: 32102983 DOI: 10.1172/jci.insight.135119] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 01/29/2020] [Indexed: 11/17/2022] Open
Abstract
Accumulation of amyloid β protein (Aβ) due to increased generation and/or impaired degradation plays an important role in Alzheimer's disease (AD) pathogenesis. In this report, we describe the identification of rare coding mutations in the endothelin-converting enzyme 2 (ECE2) gene in 1 late-onset AD family, and additional case-control cohort analysis indicates ECE2 variants associated with the risk of developing AD. The 2 mutations (R186C and F751S) located in the peptidase domain in the ECE2 protein were found to severely impair the enzymatic activity of ECE2 in Aβ degradation. We further evaluated the effect of the R186C mutation in mutant APP-knockin mice. Overexpression of wild-type ECE2 in the hippocampus reduced amyloid load and plaque formation, and improved learning and memory deficits in the AD model mice. However, the effect was abolished by the R186C mutation in ECE2. Taken together, the results demonstrated that ECE2 peptidase mutations contribute to AD pathogenesis by impairing Aβ degradation, and overexpression of ECE2 alleviates AD phenotypes. This study indicates that ECE2 is a risk gene for AD development and pharmacological activation of ECE2 could be a promising strategy for AD treatment.
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Affiliation(s)
- Xinxin Liao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, Canada.,National Clinical Research Center for Geriatric Disorders
| | - Fang Cai
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, Canada
| | - Zhanfang Sun
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders
| | - Yun Zhang
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, Canada
| | - Juelu Wang
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, Canada
| | - Bin Jiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders
| | - Jifeng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China
| | - Jinchen Li
- National Clinical Research Center for Geriatric Disorders
| | - Xixi Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders
| | - Lina Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders
| | - Yafang Zhou
- National Clinical Research Center for Geriatric Disorders
| | - Junling Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders
| | - Xinxiang Yan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China
| | - Kun Xia
- School of Life Sciences, and
| | | | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China
| | - Lu Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, Canada
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22
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Castro A, Coria-Lucero C, Anzulovich A, Navigatore-Fonzo L. Effects of experimental intracerebral ventricular injection of amyloid beta peptide (1-42) aggregates on daily rhythms of Aβ-degrading enzymes in the hippocampus: Relevance to Alzheimer's disease pathophysiology. PATHOPHYSIOLOGY 2019; 26:281-287. [DOI: 10.1016/j.pathophys.2019.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 06/24/2019] [Accepted: 07/27/2019] [Indexed: 11/30/2022] Open
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23
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Fetahu IS, Ma D, Rabidou K, Argueta C, Smith M, Liu H, Wu F, Shi YG. Epigenetic signatures of methylated DNA cytosine in Alzheimer's disease. SCIENCE ADVANCES 2019; 5:eaaw2880. [PMID: 31489368 PMCID: PMC6713504 DOI: 10.1126/sciadv.aaw2880] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 07/18/2019] [Indexed: 05/23/2023]
Abstract
Alzheimer's disease (AD), a progressive neurodegenerative disorder, is the most common untreatable form of dementia. Identifying molecular biomarkers that allow early detection remains a key challenge in the diagnosis, treatment, and prognostic evaluation of the disease. Here, we report a novel experimental and analytical model characterizing epigenetic alterations during AD onset and progression. We generated the first integrated base-resolution genome-wide maps of the distribution of 5-methyl-cytosine (5mC), 5-hydroxymethyl-cytosine (5hmC), and 5-formyl/carboxy-cytosine (5fC/caC) in normal and AD neurons. We identified 27 AD region-specific and 39 CpG site-specific epigenetic signatures that were independently validated across our familial and sporadic AD models, and in an independent clinical cohort. Thus, our work establishes a new model and strategy to study the epigenetic alterations underlying AD onset and progression and provides a set of highly reliable AD-specific epigenetic signatures that may have early diagnostic and prognostic implications.
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Affiliation(s)
- Irfete S. Fetahu
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Dingailu Ma
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Laboratory of Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Kimberlie Rabidou
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
| | - Christian Argueta
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
| | - Michael Smith
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
| | - Hang Liu
- Laboratory of Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China
| | - Feizhen Wu
- Laboratory of Epigenetics, Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Yujiang G. Shi
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Harvard Medical School, Boston, MA 02115, USA
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24
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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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25
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Profiling of Alzheimer’s disease related genes in mild to moderate vitamin D hypovitaminosis. J Nutr Biochem 2019; 67:123-137. [DOI: 10.1016/j.jnutbio.2019.01.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 12/13/2018] [Accepted: 01/29/2019] [Indexed: 02/01/2023]
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26
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Quitterer U, AbdAlla S. Improvements of symptoms of Alzheimer`s disease by inhibition of the angiotensin system. Pharmacol Res 2019; 154:104230. [PMID: 30991105 DOI: 10.1016/j.phrs.2019.04.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 04/10/2019] [Accepted: 04/11/2019] [Indexed: 01/30/2023]
Abstract
With ageing of the global society, the frequency of ageing-related neurodegenerative diseases such as Alzheimer`s disease (AD) is on the rise worldwide. Currently, there is no cure for AD, and the four drugs approved for AD only have very small effects on AD symptoms. Consequently, there are enormous efforts worldwide to identify new targets for treatment of AD. Approaches that interfere with classical neuropathologic features of AD, such as extracellular senile plaques formed of aggregated amyloid-beta (Abeta), and intracellular neurofibrillary tangles of hyperphosphorylated tau have not been successful so far. In search for a treatment approach of AD, we found that inhibition of the angiotensin-converting enzyme (ACE) by a centrally acting ACE inhibitor retards symptoms of neurodegeneration, Abeta plaque formation and tau hyperphosphorylation in experimental models of AD. Our approach is currently being investigated in a clinical setting. Initial evidence with AD patients shows that a brain-penetrating ACE inhibitor counteracts the process of neurodegeneration and dementia. Moreover, centrally acting ACE inhibitors given in addition to the standard therapy, cholinesterase inhibition, can improve cognitive function of AD patients for several months. This is one of the most promising results for AD treatment since more than a decade.
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Affiliation(s)
- Ursula Quitterer
- Molecular Pharmacology, Department of Chemistry and Applied Biosciences, ETH Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland; Institute of Pharmacology and Toxicology, Department of Medicine, University of Zurich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland.
| | - Said AbdAlla
- Molecular Pharmacology, Department of Chemistry and Applied Biosciences, ETH Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
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27
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Sikanyika NL, Parkington HC, Smith AI, Kuruppu S. Powering Amyloid Beta Degrading Enzymes: A Possible Therapy for Alzheimer's Disease. Neurochem Res 2019; 44:1289-1296. [PMID: 30806879 DOI: 10.1007/s11064-019-02756-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 02/15/2019] [Accepted: 02/17/2019] [Indexed: 12/23/2022]
Abstract
The accumulation of amyloid beta (Aβ) in the brain is believed to play a central role in the development and progression of Alzheimer's disease. Revisions to the amyloid cascade hypothesis now acknowledge the dynamic equilibrium in which Aβ exists and the importance of enzymes involved in the production and breakdown of Aβ in maintaining healthy Aβ levels. However, while a wealth of pharmacological and immunological therapies are being generated to inhibit the Aβ-producing enzymes, β-site APP cleavage enzyme 1 and γ-secretase, the therapeutic potential of stimulating Aβ-degrading enzymes such as neprilysin, endothelin-converting enzyme-1 and insulin-degrading enzyme remains relatively unexplored. Recent evidence indicates that increasing Aβ degradation as opposed to inhibiting synthesis is a more effective strategy to prevent Aβ build-up. Therefore Aβ degrading enzymes have become valuable targets of therapy. In this review, we discuss the pathway of Aβ synthesis and clearance along with the opportunities they present for therapeutic intervention, the benefits of increasing the expression/activity of Aβ-degrading enzymes, and the untapped therapeutic potential of enzyme activation.
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Affiliation(s)
- Nkumbu L Sikanyika
- Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Helena C Parkington
- Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - A Ian Smith
- Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Sanjaya Kuruppu
- Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
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28
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Zhang M, Wu Q, Yao X, Zhao J, Zhong W, Liu Q, Xiao S. Xanthohumol inhibits tau protein aggregation and protects cells against tau aggregates. Food Funct 2019; 10:7865-7874. [DOI: 10.1039/c9fo02133g] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Xanthohumol is shown to interact with tau protein and inhibit its aggregation.
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Affiliation(s)
- Mohan Zhang
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
| | - Qiuping Wu
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
| | - Xuanbao Yao
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
| | - Junyi Zhao
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
| | - Weicong Zhong
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
| | - Qiong Liu
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
| | - Shifeng Xiao
- Shenzhen Key Laboratory of Marine Biotechnology and Ecology
- College of Life Sciences and Oceanography
- Shenzhen University
- Shenzhen
- China
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29
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Davenport AP, Kuc RE, Southan C, Maguire JJ. New drugs and emerging therapeutic targets in the endothelin signaling pathway and prospects for personalized precision medicine. Physiol Res 2018; 67:S37-S54. [PMID: 29947527 DOI: 10.33549/physiolres.933872] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
During the last thirty years since the discovery of endothelin-1, the therapeutic strategy that has evolved in the clinic, mainly in the treatment of pulmonary arterial hypertension, is to block the action of the peptide either at the ET(A) subtype or both receptors using orally active small molecule antagonists. Recently, there has been a rapid expansion in research targeting ET receptors using chemical entities other than small molecules, particularly monoclonal antibody antagonists and selective peptide agonists and antagonists. While usually sacrificing oral bio-availability, these compounds have other therapeutic advantages with the potential to considerably expand drug targets in the endothelin pathway and extend treatment to other pathophysiological conditions. Where the small molecule approach has been retained, a novel strategy to combine two vasoconstrictor targets, the angiotensin AT(1) receptor as well as the ET(A) receptor in the dual antagonist sparsentan has been developed. A second emerging strategy is to combine drugs that have two different targets, the ET(A) antagonist ambrisentan with the phosphodiesterase inhibitor tadalafil, to improve the treatment of pulmonary arterial hypertension. The solving of the crystal structure of the ET(B) receptor has the potential to identify allosteric binding sites for novel ligands. A further key advance is the experimental validation of a single nucleotide polymorphism that has genome wide significance in five vascular diseases and that significantly increases the amount of big endothelin-1 precursor in the plasma. This observation provides a rationale for testing this single nucleotide polymorphism to stratify patients for allocation to treatment with endothelin agents and highlights the potential to use personalized precision medicine in the endothelin field.
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Affiliation(s)
- A P Davenport
- Experimental Medicine and Immunotherapeutics, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
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30
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Lanza V, Bellia F, Rizzarelli E. An inorganic overview of natural Aβ fragments: Copper(II) and zinc(II)-mediated pathways. Coord Chem Rev 2018. [DOI: 10.1016/j.ccr.2018.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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31
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Insulin-signaling Pathway Regulates the Degradation of Amyloid β-protein via Astrocytes. Neuroscience 2018; 385:227-236. [PMID: 29932983 DOI: 10.1016/j.neuroscience.2018.06.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 06/09/2018] [Accepted: 06/11/2018] [Indexed: 01/06/2023]
Abstract
Alzheimer's disease (AD) has been considered as a metabolic dysfunction disease associated with impaired insulin signaling. Determining the mechanisms underlying insulin signaling dysfunction and resistance in AD will be important for its treatment. Impaired clearance of amyloid-β peptide (Aβ) significantly contributes to amyloid accumulation, which is typically observed in the brain of AD patients. Reduced expression of important Aβ-degrading enzymes in the brain, such as neprilysin (NEP) and insulin-degrading enzyme (IDE), can promote Aβ deposition in sporadic late-onset AD patients. Here, we investigated whether insulin regulates the degradation of Aβ by inducing expression of NEP and IDE in cultured astrocytes. Treatment of astrocytes with insulin significantly reduced cellular NEP levels, but increased IDE expression. The effects of insulin on the expression of NEP and IDE involved activation of an extracellular signal-regulated kinase (ERK)-mediated pathway. The reduction in cellular NEP levels was associated with NEP secretion into the culture medium, whereas IDE was increased in the cell membranes. Moreover, insulin-treated astrocytes significantly facilitated the degradation of exogenous Aβ within the culture medium. Interestingly, pretreatment of astrocytes with an ERK inhibitor prior to insulin exposure markedly inhibited insulin-induced degradation of Aβ. These results suggest that insulin exposure enhanced Aβ degradation via an increase in NEP secretion and IDE expression in astrocytes, via activation of the ERK-mediated pathway. The inhibition of insulin signaling pathways delayed Aβ degradation by attenuating alterations in NEP and IDE levels and competition with insulin and Aβ. Our results provide further insight into the pathological relevance of insulin resistance in AD development.
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32
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Alldred MJ, Chao HM, Lee SH, Beilin J, Powers BE, Petkova E, Strupp BJ, Ginsberg SD. CA1 pyramidal neuron gene expression mosaics in the Ts65Dn murine model of Down syndrome and Alzheimer's disease following maternal choline supplementation. Hippocampus 2018; 28:251-268. [PMID: 29394516 PMCID: PMC5874173 DOI: 10.1002/hipo.22832] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 12/14/2017] [Accepted: 01/23/2018] [Indexed: 12/15/2022]
Abstract
Although there are changes in gene expression and alterations in neuronal density and afferent inputs in the forebrain of trisomic mouse models of Down syndrome (DS) and Alzheimer's disease (AD), there is a lack of systematic assessments of gene expression and encoded proteins within individual vulnerable cell populations, precluding translational investigations at the molecular and cellular level. Further, no effective treatment exists to combat intellectual disability and basal forebrain cholinergic neurodegeneration seen in DS. To further our understanding of gene expression changes before and following cholinergic degeneration in a well-established mouse model of DS/AD, the Ts65Dn mouse, we assessed RNA expression levels from CA1 pyramidal neurons at two adult ages (∼6 months of age and ∼11 months of age) in both Ts65Dn and their normal disomic (2N) littermates. We further examined a therapeutic intervention, maternal choline supplementation (MCS), which has been previously shown to lessen dysfunction in spatial cognition and attention, and have protective effects on the survival of basal forebrain cholinergic neurons in the Ts65Dn mouse model. Results indicate that MCS normalized expression of several genes in key gene ontology categories, including synaptic plasticity, calcium signaling, and AD-associated neurodegeneration related to amyloid-beta peptide (Aβ) clearance. Specifically, normalized expression levels were found for endothelin converting enzyme-2 (Ece2), insulin degrading enzyme (Ide), Dyrk1a, and calcium/calmodulin-dependent protein kinase II (Camk2a), among other relevant genes. Single population expression profiling of vulnerable CA1 pyramidal neurons indicates that MCS is a viable therapeutic for long-term reprogramming of key transcripts involved in neuronal signaling that are dysregulated in the trisomic mouse brain which have translational potential for DS and AD.
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Affiliation(s)
- Melissa J. Alldred
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY
- Departments of Psychiatry, New York University Langone Medical Center, New York, NY
| | - Helen M. Chao
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY
- Departments of Psychiatry, New York University Langone Medical Center, New York, NY
| | - Sang Han Lee
- Center for Biomedical Imaging and Neuromodulation, Nathan Kline Institute, Orangeburg, NY
- Child Psychiatry, Nathan Kline Institute, Orangeburg, NY
- Departments of Psychiatry, New York University Langone Medical Center, New York, NY
- Child and Adolescent Psychiatry, New York University Langone Medical Center, New York, NY
| | - Judah Beilin
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY
| | | | - Eva Petkova
- Child Psychiatry, Nathan Kline Institute, Orangeburg, NY
- Child and Adolescent Psychiatry, New York University Langone Medical Center, New York, NY
| | - Barbara J. Strupp
- Division of Nutritional Sciences, Cornell University, Ithaca, NY
- Department of Psychology, Cornell University, Ithaca, NY
| | - Stephen D. Ginsberg
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY
- Departments of Psychiatry, New York University Langone Medical Center, New York, NY
- Neuroscience & Physiology, New York University Langone Medical Center, New York, NY
- NYU Neuroscience Institute, New York University Langone Medical Center, New York, NY
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Yao P, Zhuo S, Mei H, Chen X, Li N, Zhu T, Chen S, Wang J, Hou R, Le Y. Androgen alleviates neurotoxicity of β-amyloid peptide (Aβ) by promoting microglial clearance of Aβ and inhibiting microglial inflammatory response to Aβ. CNS Neurosci Ther 2017; 23:855-865. [PMID: 28941188 PMCID: PMC6492702 DOI: 10.1111/cns.12757] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/30/2017] [Accepted: 09/01/2017] [Indexed: 12/24/2022] Open
Abstract
AIMS Lower androgen level in elderly men is a risk factor of Alzheimer's disease (AD). It has been reported that androgen reduces amyloid peptides (Aβ) production and increases Aβ degradation by neurons. Activated microglia are involved in AD by either clearing Aβ deposits through uptake of Aβ or releasing cytotoxic substances and pro-inflammatory cytokines. Here, we investigated the effect of androgen on Aβ uptake and clearance and Aβ-induced inflammatory response in microglia, on neuronal death induced by Aβ-activated microglia, and explored underlying mechanisms. METHODS Intracellular and extracellular Aβ were examined by immunofluorescence staining and Western blot. Amyloid peptides (Aβ) receptors, Aβ degrading enzymes, and pro-inflammatory cytokines were detected by RT-PCR, real-time PCR, and ELISA. Phosphorylation of MAP kinases and NF-κB was examined by Western blot. RESULTS We found that physiological concentrations of androgen enhanced Aβ42 uptake and clearance, suppressed Aβ42 -induced IL-1β and TNFα expression by murine microglia cell line N9 and primary microglia, and alleviated neuronal death induced by Aβ42 -activated microglia. Androgen administration also reduced Aβ42 -induced IL-1β expression and neuronal death in murine hippocampus. Mechanistic studies revealed that androgen promoted microglia to phagocytose and degrade Aβ42 through upregulating formyl peptide receptor 2 and endothelin-converting enzyme 1c expression, and inhibited Aβ42 -induced pro-inflammatory cytokines expression via suppressing MAPK p38 and NF-κB activation by Aβ42 , in an androgen receptor independent manner. CONCLUSION Our study demonstrates that androgen promotes microglia to phagocytose and clear Aβ42 and inhibits Aβ42 -induced inflammatory response, which may play an important role in reducing the neurotoxicity of Aβ.
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Affiliation(s)
- Peng‐Le Yao
- Key Laboratory of Food Safety ResearchChinese Academy of SciencesInstitute for Nutritional SciencesShanghai Institutes for Biological SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Shu Zhuo
- Key Laboratory of Food Safety ResearchChinese Academy of SciencesInstitute for Nutritional SciencesShanghai Institutes for Biological SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Hong Mei
- Key Laboratory of Food Safety ResearchChinese Academy of SciencesInstitute for Nutritional SciencesShanghai Institutes for Biological SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Xiao‐Fang Chen
- Key Laboratory of Food Safety ResearchChinese Academy of SciencesInstitute for Nutritional SciencesShanghai Institutes for Biological SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Na Li
- Key Laboratory of Food Safety ResearchChinese Academy of SciencesInstitute for Nutritional SciencesShanghai Institutes for Biological SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Teng‐Fei Zhu
- Key Laboratory of Food Safety ResearchChinese Academy of SciencesInstitute for Nutritional SciencesShanghai Institutes for Biological SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Shi‐Ting Chen
- Key Laboratory of Food Safety ResearchChinese Academy of SciencesInstitute for Nutritional SciencesShanghai Institutes for Biological SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Ji‐Ming Wang
- Cancer and Inflammation ProgramCenter for Cancer ResearchNational Cancer Institute at FrederickFrederickMDUSA
| | - Rui‐Xing Hou
- Ruihua Affiliated Hospital of Soochow UniversitySuzhouChina
| | - Ying‐Ying Le
- Key Laboratory of Food Safety ResearchChinese Academy of SciencesInstitute for Nutritional SciencesShanghai Institutes for Biological SciencesUniversity of Chinese Academy of SciencesShanghaiChina
- Ruihua Affiliated Hospital of Soochow UniversitySuzhouChina
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Yamamoto N, Shibata M, Ishikuro R, Tanida M, Taniguchi Y, Ikeda-Matsuo Y, Sobue K. Epigallocatechin gallate induces extracellular degradation of amyloid β-protein by increasing neprilysin secretion from astrocytes through activation of ERK and PI3K pathways. Neuroscience 2017; 362:70-78. [DOI: 10.1016/j.neuroscience.2017.08.030] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/08/2017] [Accepted: 08/15/2017] [Indexed: 01/29/2023]
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Chen GF, Xu TH, Yan Y, Zhou YR, Jiang Y, Melcher K, Xu HE. Amyloid beta: structure, biology and structure-based therapeutic development. Acta Pharmacol Sin 2017; 38:1205-1235. [PMID: 28713158 PMCID: PMC5589967 DOI: 10.1038/aps.2017.28] [Citation(s) in RCA: 989] [Impact Index Per Article: 141.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 03/02/2017] [Indexed: 12/12/2022] Open
Abstract
Amyloid beta peptide (Aβ) is produced through the proteolytic processing of a transmembrane protein, amyloid precursor protein (APP), by β- and γ-secretases. Aβ accumulation in the brain is proposed to be an early toxic event in the pathogenesis of Alzheimer's disease, which is the most common form of dementia associated with plaques and tangles in the brain. Currently, it is unclear what the physiological and pathological forms of Aβ are and by what mechanism Aβ causes dementia. Moreover, there are no efficient drugs to stop or reverse the progression of Alzheimer's disease. In this paper, we review the structures, biological functions, and neurotoxicity role of Aβ. We also discuss the potential receptors that interact with Aβ and mediate Aβ intake, clearance, and metabolism. Additionally, we summarize the therapeutic developments and recent advances of different strategies for treating Alzheimer's disease. Finally, we will report on the progress in searching for novel, potentially effective agents as well as selected promising strategies for the treatment of Alzheimer's disease. These prospects include agents acting on Aβ, its receptors and tau protein, such as small molecules, vaccines and antibodies against Aβ; inhibitors or modulators of β- and γ-secretase; Aβ-degrading proteases; tau protein inhibitors and vaccines; amyloid dyes and microRNAs.
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Affiliation(s)
- Guo-Fang Chen
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Ting-Hai Xu
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yan Yan
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yu-Ren Zhou
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yi Jiang
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Karsten Melcher
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - H Eric Xu
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, MI 49503, USA
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36
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Newman SA, Pan Y, Short JL, Nicolazzo JA. Assessing the Impact of Lithium Chloride on the Expression of P-Glycoprotein at the Blood-Brain Barrier. J Pharm Sci 2017; 106:2625-2631. [DOI: 10.1016/j.xphs.2017.01.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/19/2016] [Accepted: 01/05/2017] [Indexed: 12/14/2022]
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37
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Kikuchi K, Kidana K, Tatebe T, Tomita T. Dysregulated Metabolism of the Amyloid‐β Protein and Therapeutic Approaches in Alzheimer Disease. J Cell Biochem 2017; 118:4183-4190. [DOI: 10.1002/jcb.26129] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 05/08/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Kazunori Kikuchi
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical SciencesThe University of TokyoTokyoJapan
| | - Kiwami Kidana
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical SciencesThe University of TokyoTokyoJapan
| | - Takuya Tatebe
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical SciencesThe University of TokyoTokyoJapan
| | - Taisuke Tomita
- Laboratory of Neuropathology and Neuroscience, Graduate School of Pharmaceutical SciencesThe University of TokyoTokyoJapan
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Smith-Anttila CJA, Bensing S, Alimohammadi M, Dalin F, Oscarson M, Zhang MD, Perheentupa J, Husebye ES, Gustafsson J, Björklund P, Fransson A, Nordmark G, Rönnblom L, Meloni A, Scott RJ, Hökfelt T, Crock PA, Kämpe O. Identification of endothelin-converting enzyme-2 as an autoantigen in autoimmune polyendocrine syndrome type 1. Autoimmunity 2017; 50:223-231. [PMID: 28557628 DOI: 10.1080/08916934.2017.1332183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Autoimmune polyendocrine syndrome type 1 (APS1) is a rare monogenic autoimmune disorder caused by mutations in the autoimmune regulator (AIRE) gene. High titer autoantibodies are a characteristic feature of APS1 and are often associated with particular disease manifestations. Pituitary deficits are reported in up to 7% of all APS1 patients, with immunoreactivity to pituitary tissue frequently reported. We aimed to isolate and identify specific pituitary autoantigens in patients with APS1. Immunoscreening of a pituitary cDNA expression library identified endothelin-converting enzyme (ECE)-2 as a potential candidate autoantigen. Immunoreactivity against ECE-2 was detected in 46% APS1 patient sera, with no immunoreactivity detectable in patients with other autoimmune disorders or healthy controls. Quantitative-PCR showed ECE-2 mRNA to be most abundantly expressed in the pancreas with high levels also in the pituitary and brain. In the pancreas ECE-2 was co-expressed with insulin or somatostatin, but not glucagon and was widely expressed in GH producing cells in the guinea pig pituitary. The correlation between immunoreactivity against ECE-2 and the major recognized clinical phenotypes of APS1 including hypopituitarism was not apparent. Our results identify ECE-2 as a specific autoantigen in APS1 with a restricted neuroendocrine distribution.
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Affiliation(s)
- Casey J. A. Smith-Anttila
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
- Department of Paediatric Endocrinology and Diabetes, John Hunter Children’s Hospital and Faculty of Health and Medicine, University of Newcastle, Newcastle, Australia
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Australia
| | - Sophie Bensing
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | | | - Frida Dalin
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
- Department of Medicine (Solna), Centre for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Mikael Oscarson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Ming-Dong Zhang
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Medical Biochemistry and Biophysics, Division of Molecular Neurobiology, Karolinska Institutet, Stockholm, Sweden
| | - Jaakko Perheentupa
- Hospital for Children and Adolescents, Helsinki University Hospital, Helsinki, Finland
| | - Eystein S. Husebye
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Jan Gustafsson
- Department of Women’s and Children’s Health, Uppsala University, Uppsala, Sweden
| | - Peyman Björklund
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Anette Fransson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Gunnel Nordmark
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Lars Rönnblom
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Antonella Meloni
- Department of Biomedical Biotechnological Sciences, University of Cagliari, Cagliari, Italy
| | - Rodney J. Scott
- Information Based Medicine, Hunter Medical Research Institute and School of Biomedical Sciences, Faculty of Health and Medicine, University of Newcastle, Australia
- Division of Molecular Medicine, Hunter Area Pathology Service, Newcastle, NSW, Australia
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Patricia A. Crock
- Department of Paediatric Endocrinology and Diabetes, John Hunter Children’s Hospital and Faculty of Health and Medicine, University of Newcastle, Newcastle, Australia
- Division of Molecular Medicine, Hunter Area Pathology Service, Newcastle, NSW, Australia
| | - Olle Kämpe
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
- Department of Medicine (Solna), Centre for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
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Huang C, Dong D, Jiao Q, Pan H, Ma L, Wang R. Sarsasapogenin-AA13 ameliorates Aβ-induced cognitive deficits via improving neuroglial capacity on Aβ clearance and antiinflammation. CNS Neurosci Ther 2017; 23:498-509. [PMID: 28466999 DOI: 10.1111/cns.12697] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/11/2017] [Accepted: 03/17/2017] [Indexed: 01/14/2023] Open
Abstract
AIMS Sarsasapogenin has been reported to improve dementia symptoms somehow, probably through modulating the function of cholinergic system, suppressing neurofibrillary tangles, and inhibiting inflammation. However, the role of sarsasapogenin in response to beta-amyloid (Aβ) remains to be delineated. This study aimed to determine the therapeutic effect of sarsasapogenin-13 (AA13, a sarsasapogenin derivative) on learning and memory impairments in Aβ-injected mice, as well as the role of AA13 in neuroglia-mediated antiinflammation and Aβ clearance. METHODS Focusing on the role of AA13 in regulating glial responses to Aβ, we conducted behavioral, morphological, and protein expression studies to explore the effects of AA13 on Aβ clearance and inflammatory regulation. RESULTS The results indicated that oral administration of AA13 attenuated the memory deficits of intracerebroventricular (i.c.v.) Aβ-injected mice; also, AA13 protected neuroglial cells against Aβ-induced cytotoxicity. The further mechanical studies demonstrated that AA13 reversed the upregulation of proinflammatory M1 markers and increased the expression of antiinflammatory M2 markers in Aβ-treated cells. Furthermore, AA13 facilitated Aβ clearance through promoting Aβ phagocytosis and degradation. AA13 modulated the expression of fatty acid translocase (CD36), insulin-degrading enzyme (IDE), neprilysin (NEP), and endothelin-converting enzyme (ECE) in neuroglia. CONCLUSION The present study indicated that the neuroprotective effect of AA13 might relate to its modulatory effects on microglia activation state, phagocytic ability, and expression of Aβ-degrading enzymes, which makes it a promising therapeutic agent in the early stage of Alzheimer's disease (AD).
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Affiliation(s)
- Cui Huang
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Dong Dong
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Qian Jiao
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Hui Pan
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Lei Ma
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
| | - Rui Wang
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai, China
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Miners JS, Love S. Endothelin-converting enzymes degrade α-synuclein and are reduced in dementia with Lewy bodies. J Neurochem 2017; 141:275-286. [PMID: 28171705 DOI: 10.1111/jnc.13974] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 01/17/2017] [Accepted: 01/26/2017] [Indexed: 01/12/2023]
Abstract
We have examined the roles of the endothelin-converting enzyme-1 and -2 (ECE-1 and ECE-2) in the homeostasis of α-synuclein (α-syn) and pathogenesis of Lewy body disease. The ECEs are named for their ability to convert inactive big endothelin to the vasoactive peptide endothelin-1 (EDN1). We have found that ECE-1 and ECE-2 cleave and degrade α-syn in vitro and siRNA-mediated knockdown of ECE-1 and ECE-2 in SH-SY5Y neuroblastoma cells significantly increased α-syn both intracellularly (within the cell lysate) (p < 0.05 for both ECE-1 and -2) and extracellularly (in the surrounding medium) (p < 0.05 for ECE-1 and p = 0.07 for ECE-2). Double immunofluorescent labelling showed co-localization of ECE-1 and ECE-2 with α-syn within the endolysosomal system (confirmed by a proximity ligation assay). To assess the possible relevance of these findings to human Lewy body disease, we measured ECE-1 and ECE-2 levels by sandwich ELISA in post-mortem samples of cingulate cortex (a region with a predilection for Lewy body pathology) in dementia with Lewy bodies (DLB) and age-matched controls. ECE-1 (p < 0.001) and ECE-2 (p < 0.01) levels were significantly reduced in DLB and both enzymes correlated inversely with the severity of Lewy body pathology as indicated by the level of α-syn phosphorylated at Ser129 (r = -0.54, p < 0.01 for ECE-1 and r = -0.49, p < 0.05 for ECE-2). Our novel findings suggest a role for ECEs in the metabolism of α-syn that could contribute to the development and progression of DLB.
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Affiliation(s)
| | - Seth Love
- Dementia Research Group, University of Bristol, Bristol, UK
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41
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Nookala AR, Mitra J, Chaudhari NS, Hegde ML, Kumar A. An Overview of Human Immunodeficiency Virus Type 1-Associated Common Neurological Complications: Does Aging Pose a Challenge? J Alzheimers Dis 2017; 60:S169-S193. [PMID: 28800335 PMCID: PMC6152920 DOI: 10.3233/jad-170473] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
With increasing survival of patients infected with human immunodeficiency virus type 1 (HIV-1), the manifestation of heterogeneous neurological complications is also increasing alarmingly in these patients. Currently, more than 30% of about 40 million HIV-1 infected people worldwide develop central nervous system (CNS)-associated dysfunction, including dementia, sensory, and motor neuropathy. Furthermore, the highly effective antiretroviral therapy has been shown to increase the prevalence of mild cognitive functions while reducing other HIV-1-associated neurological complications. On the contrary, the presence of neurological disorder frequently affects the outcome of conventional HIV-1 therapy. Although, both the children and adults suffer from the post-HIV treatment-associated cognitive impairment, adults, especially depending on the age of disease onset, are more prone to CNS dysfunction. Thus, addressing neurological complications in an HIV-1-infected patient is a delicate balance of several factors and requires characterization of the molecular signature of associated CNS disorders involving intricate cross-talk with HIV-1-derived neurotoxins and other cellular factors. In this review, we summarize some of the current data supporting both the direct and indirect mechanisms, including neuro-inflammation and genome instability in association with aging, leading to CNS dysfunction after HIV-1 infection, and discuss the potential strategies addressing the treatment or prevention of HIV-1-mediated neurotoxicity.
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Affiliation(s)
- Anantha Ram Nookala
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Joy Mitra
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
| | - Nitish S. Chaudhari
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Muralidhar L. Hegde
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
- Weill Cornell Medical College of Cornell University, NY, USA
| | - Anil Kumar
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO, USA
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Solé-Domènech S, Cruz DL, Capetillo-Zarate E, Maxfield FR. The endocytic pathway in microglia during health, aging and Alzheimer's disease. Ageing Res Rev 2016; 32:89-103. [PMID: 27421577 DOI: 10.1016/j.arr.2016.07.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 07/01/2016] [Accepted: 07/05/2016] [Indexed: 12/14/2022]
Abstract
Microglia, the main phagocytes of the central nervous system (CNS), are involved in the surveillance and maintenance of nervous tissue. During normal tissue homeostasis, microglia migrates within the CNS, phagocytose dead cells and tissue debris, and modulate synapse pruning and spine formation via controlled phagocytosis. In the event of an invasion by a foreign body, microglia are able to phagocytose the invading pathogen and process it proteolytically for antigen presentation. Internalized substrates are incorporated and sorted within the endocytic pathway and thereafter transported via complex vesicular routes. When targeted for degradation, substrates are delivered to acidic late endosomes and lysosomes. In these, the enzymatic degradation relies on pH and enzyme content. Endocytosis, sorting, transport, compartment acidification and degradation are regulated by complex signaling mechanisms, and these may be altered during aging and pathology. In this review, we discuss the endocytic pathway in microglia, with insight into the mechanisms controlling lysosomal biogenesis and pH regulation. We also discuss microglial lysosome function associated with Alzheimer's disease (AD) and the mechanisms of amyloid-beta (Aβ) internalization and degradation. Finally, we explore some therapies currently being investigated to treat AD and their effects on microglial response to Aβ, with insight in those involving enhancement of lysosomal function.
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43
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Duarte AC, Hrynchak MV, Gonçalves I, Quintela T, Santos CRA. Sex Hormone Decline and Amyloid β Synthesis, Transport and Clearance in the Brain. J Neuroendocrinol 2016; 28. [PMID: 27632792 DOI: 10.1111/jne.12432] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 09/12/2016] [Accepted: 09/12/2016] [Indexed: 12/15/2022]
Abstract
Sex hormones (SH) are essential regulators of the central nervous system. The decline in SH levels along with ageing may contribute to compromised neuroprotection and set the grounds for neurodegeneration and cognitive impairments. In Alzheimer's disease, besides other pathological features, there is an imbalance between amyloid β (Aβ) production and clearance, leading to its accumulation in the brain of older subjects. Aβ accumulation is a primary cause for brain inflammation and degeneration, as well as concomitant cognitive decline. There is mounting evidence that SH modulate Aβ production, transport and clearance. Importantly, SH regulate most of the molecules involved in the amyloidogenic pathway, their transport across brain barriers for elimination, and their degradation in the brain interstitial fluid. This review brings together data on the regulation of Aβ production, metabolism, degradation and clearance by SH.
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Affiliation(s)
- A C Duarte
- Health Sciences Research Centre - CICS-UBI, University of Beira Interior, Covilhã, Portugal
| | - M V Hrynchak
- Health Sciences Research Centre - CICS-UBI, University of Beira Interior, Covilhã, Portugal
| | - I Gonçalves
- Health Sciences Research Centre - CICS-UBI, University of Beira Interior, Covilhã, Portugal
| | - T Quintela
- Health Sciences Research Centre - CICS-UBI, University of Beira Interior, Covilhã, Portugal
| | - C R A Santos
- Health Sciences Research Centre - CICS-UBI, University of Beira Interior, Covilhã, Portugal
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Love S, Miners J. Cerebral Hypoperfusion and the Energy Deficit in Alzheimer's Disease. Brain Pathol 2016; 26:607-17. [PMID: 27327656 PMCID: PMC8028913 DOI: 10.1111/bpa.12401] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 06/21/2016] [Accepted: 05/25/2016] [Indexed: 12/19/2022] Open
Abstract
There is a perfusion deficit in Alzheimer's disease (AD), commencing in the precuneus and spreading to other parts of the cerebral cortex. The deficit anticipates the development of dementia, contributes to brain damage, and is caused by both functional and structural abnormalities of the cerebral vasculature. Most of the abnormalities are probably secondary to the accumulation of Aβ but the consequent hypoperfusion may, in turn, increase Aβ production. In the early stages of disease, abnormalities that cause vasoconstriction predominate. These include cholinergic vascular denervation, inhibition of endothelial nitric oxide synthase, increased production of endothelin-1 production and possibly also of angiotensin II. Patients with AD also have an increased prevalence of structural disease of cerebral microvessels, particularly CAA and capillary damage, and particularly in the later stages of disease these are likely to make an important contribution to the cerebral hypoperfusion. The metabolic abnormalities that cause early vascular dysfunction offer several targets for therapeutic intervention. However, for intervention to be effective it probably needs to be early. Prolonged cerebral hypoperfusion may induce compensatory circulatory changes that are themselves damaging, including hypertension and small vessel disease. This has implications for the use of antihypertensive drugs once there is accumulation of Aβ within the brain.
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Affiliation(s)
- Seth Love
- Dementia Research Group, Institute of Clinical Neurosciences, School of Clinical SciencesUniversity of BristolBristolUnited Kingom
| | - J.Scott Miners
- Dementia Research Group, Institute of Clinical Neurosciences, School of Clinical SciencesUniversity of BristolBristolUnited Kingom
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Pacheco-Quinto J, Eckman CB, Eckman EA. Major amyloid-β-degrading enzymes, endothelin-converting enzyme-2 and neprilysin, are expressed by distinct populations of GABAergic interneurons in hippocampus and neocortex. Neurobiol Aging 2016; 48:83-92. [PMID: 27644077 DOI: 10.1016/j.neurobiolaging.2016.08.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 08/10/2016] [Accepted: 08/12/2016] [Indexed: 01/17/2023]
Abstract
Impaired clearance of amyloid-β peptide (Aβ) has been postulated to significantly contribute to the amyloid accumulation typical of Alzheimer's disease. Among the enzymes known to degrade Aβ in vivo are endothelin-converting enzyme (ECE)-1, ECE-2, and neprilysin (NEP), and evidence suggests that they regulate independent pools of Aβ that may be functionally significant. To better understand the differential regulation of Aβ concentration by its physiological degrading enzymes, we characterized the cell and region-specific expression pattern of ECE-1, ECE-2, and NEP by in situ hybridization and immunohistochemistry in brain areas relevant to Alzheimer's disease. In contrast to the broader distribution of ECE-1, ECE-2 and NEP were found enriched in GABAergic neurons. ECE-2 was majorly expressed by somatostatin-expressing interneurons and was active in isolated synaptosomes. NEP messenger RNA was found mainly in parvalbumin-expressing interneurons, with NEP protein localized to perisomatic parvalbuminergic synapses. The identification of somatostatinergic and parvalbuminergic synapses as hubs for Aβ degradation is consistent with the possibility that Aβ may have a physiological function related to the regulation of inhibitory signaling.
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Affiliation(s)
- Javier Pacheco-Quinto
- Atlantic Health System, Morristown, NJ, USA; Biomedical Research Institute of New Jersey, Cedar Knolls, NJ, USA
| | - Christopher B Eckman
- Atlantic Health System, Morristown, NJ, USA; Biomedical Research Institute of New Jersey, Cedar Knolls, NJ, USA
| | - Elizabeth A Eckman
- Atlantic Health System, Morristown, NJ, USA; Biomedical Research Institute of New Jersey, Cedar Knolls, NJ, USA.
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Ries M, Sastre M. Mechanisms of Aβ Clearance and Degradation by Glial Cells. Front Aging Neurosci 2016; 8:160. [PMID: 27458370 PMCID: PMC4932097 DOI: 10.3389/fnagi.2016.00160] [Citation(s) in RCA: 340] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 06/17/2016] [Indexed: 12/24/2022] Open
Abstract
Glial cells have a variety of functions in the brain, ranging from immune defense against external and endogenous hazardous stimuli, regulation of synaptic formation, calcium homeostasis, and metabolic support for neurons. Their dysregulation can contribute to the development of neurodegenerative disorders, including Alzheimer’s disease (AD). One of the most important functions of glial cells in AD is the regulation of Amyloid-β (Aβ) levels in the brain. Microglia and astrocytes have been reported to play a central role as moderators of Aβ clearance and degradation. The mechanisms of Aβ degradation by glial cells include the production of proteases, including neprilysin, the insulin degrading enzyme, and the endothelin-converting enzymes, able to hydrolyse Aβ at different cleavage sites. Besides these enzymes, other proteases have been described to have some role in Aβ elimination, such as plasminogen activators, angiotensin-converting enzyme, and matrix metalloproteinases. Other relevant mediators that are released by glial cells are extracellular chaperones, involved in the clearance of Aβ alone or in association with receptors/transporters that facilitate their exit to the blood circulation. These include apolipoproteins, α2macroglobulin, and α1-antichymotrypsin. Finally, astrocytes and microglia have an essential role in phagocytosing Aβ, in many cases via a number of receptors that are expressed on their surface. In this review, we examine all of these mechanisms, providing an update on the latest research in this field.
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Affiliation(s)
- Miriam Ries
- Division of Brain Sciences, Imperial College London, Hammersmith Hospital London, UK
| | - Magdalena Sastre
- Division of Brain Sciences, Imperial College London, Hammersmith Hospital London, UK
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47
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Structure of amyloid oligomers and their mechanisms of toxicities: Targeting amyloid oligomers using novel therapeutic approaches. Eur J Med Chem 2016; 114:41-58. [DOI: 10.1016/j.ejmech.2016.02.065] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 02/25/2016] [Accepted: 02/25/2016] [Indexed: 01/22/2023]
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Love S, Miners JS. Cerebrovascular disease in ageing and Alzheimer's disease. Acta Neuropathol 2016; 131:645-58. [PMID: 26711459 PMCID: PMC4835514 DOI: 10.1007/s00401-015-1522-0] [Citation(s) in RCA: 200] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 12/03/2015] [Accepted: 12/07/2015] [Indexed: 12/14/2022]
Abstract
Cerebrovascular disease (CVD) and Alzheimer’s disease (AD) have more in common than their association with ageing. They share risk factors and overlap neuropathologically. Most patients with AD have Aβ amyloid angiopathy and degenerative changes affecting capillaries, and many have ischaemic parenchymal abnormalities. Structural vascular disease contributes to the ischaemic abnormalities in some patients with AD. However, the stereotyped progression of hypoperfusion in this disease, affecting first the precuneus and cingulate gyrus, then the frontal and temporal cortex and lastly the occipital cortex, suggests that other factors are more important, particularly in early disease. Whilst demand for oxygen and glucose falls in late disease, functional MRI, near infrared spectroscopy to measure the saturation of haemoglobin by oxygen, and biochemical analysis of myelin proteins with differential susceptibility to reduced oxygenation have all shown that the reduction in blood flow in AD is primarily a problem of inadequate blood supply, not reduced metabolic demand. Increasing evidence points to non-structural vascular dysfunction rather than structural abnormalities of vessel walls as the main cause of cerebral hypoperfusion in AD. Several mediators are probably responsible. One that is emerging as a major contributor is the vasoconstrictor endothelin-1 (EDN1). Whilst there is clearly an additive component to the clinical and pathological effects of hypoperfusion and AD, experimental and clinical observations suggest that the disease processes also interact mechanistically at a cellular level in a manner that exacerbates both. The elucidation of some of the mechanisms responsible for hypoperfusion in AD and for the interactions between CVD and AD has led to the identification of several novel therapeutic approaches that have the potential to ameliorate ischaemic damage and slow the progression of neurodegenerative disease.
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Affiliation(s)
- Seth Love
- Institute of Clinical Neurosciences, School of Clinical Sciences, Learning and Research Level 2, Southmead Hospital, University of Bristol, Bristol, BS10 5NB, UK.
| | - J Scott Miners
- Institute of Clinical Neurosciences, School of Clinical Sciences, Learning and Research Level 2, Southmead Hospital, University of Bristol, Bristol, BS10 5NB, UK
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Sun X, Chen WD, Wang YD. β-Amyloid: the key peptide in the pathogenesis of Alzheimer's disease. Front Pharmacol 2015; 6:221. [PMID: 26483691 PMCID: PMC4588032 DOI: 10.3389/fphar.2015.00221] [Citation(s) in RCA: 187] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 09/17/2015] [Indexed: 12/20/2022] Open
Abstract
The amyloid β peptide (Aβ) is a critical initiator that triggers the progression of Alzheimer's Disease (AD) via accumulation and aggregation, of which the process may be caused by Aβ overproduction or perturbation clearance. Aβ is generated from amyloid precursor protein through sequential cleavage of β- and γ-secretases while Aβ removal is dependent on the proteolysis and lysosome degradation system. Here, we overviewed the biogenesis and toxicity of Aβ as well as the regulation of Aβ production and clearance. Moreover, we also summarized the animal models correlated with Aβ that are essential in AD research. In addition, we discussed current immunotherapeutic approaches targeting Aβ to give some clues for exploring the more potentially efficient drugs for treatment of AD.
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Affiliation(s)
- Xiaojuan Sun
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Medicine, Henan University Kaifeng, China
| | - Wei-Dong Chen
- Key Laboratory of Receptors-Mediated Gene Regulation and Drug Discovery, School of Medicine, Henan University Kaifeng, China
| | - Yan-Dong Wang
- State Key Laboratory of Chemical Resource Engineering, College of Life Science and Technology, Beijing University of Chemical Technology Beijing, China
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50
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Love S, Miners JS. White matter hypoperfusion and damage in dementia: post-mortem assessment. Brain Pathol 2015; 25:99-107. [PMID: 25521180 DOI: 10.1111/bpa.12223] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 10/08/2014] [Indexed: 01/19/2023] Open
Abstract
Neuroimaging has revealed a range of white matter abnormalities that are common in dementia, some that predict cognitive decline. The abnormalities may result from structural diseases of the cerebral vasculature, such as arteriolosclerosis and amyloid angiopathy, but can also be caused by nonstructural vascular abnormalities (eg, of vascular contractility or permeability), neurovascular instability or extracranial cardiac or vascular disease. Conventional histopathological assessment of the white matter has tended to conflate morphological vascular abnormalities with changes that reflect altered interstitial fluid dynamics or white matter ischemic damage, even though the latter may be of extracranial or nonstructural etiology. However, histopathology is being supplemented by biochemical approaches, including the measurement of proteins involved in the molecular responses to brain ischemia, myelin proteins differentially susceptible to ischemic damage, vessel-associated proteins that allow rapid measurement of microvessel density, markers of blood-brain barrier dysfunction and axonal injury, and mediators of white matter damage. By combining neuroimaging with histopathology and biochemical analysis, we can provide reproducible, quantitative data on the severity of white matter damage, and information on its etiology and pathogenesis. Together these have the potential to inform and improve treatment, particularly in forms of dementia to which white matter hypoperfusion makes a significant contribution.
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Affiliation(s)
- Seth Love
- Dementia Research Group, Institute of Clinical Neurosciences, University of Bristol, Learning and Research Level 2, Southmead Hospital, Bristol, UK
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