1
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Li S, Roy ER, Wang Y, Watkins T, Cao W. DLK-MAPK Signaling Coupled with DNA Damage Promotes Intrinsic Neurotoxicity Associated with Non-Mutated Tau. Mol Neurobiol 2024; 61:2978-2995. [PMID: 37955806 PMCID: PMC11043018 DOI: 10.1007/s12035-023-03720-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 10/17/2023] [Indexed: 11/14/2023]
Abstract
Alzheimer's disease (AD) is the most prevalent form of neurodegeneration. Despite the well-established link between tau aggregation and clinical progression, the major pathways driven by this protein to intrinsically damage neurons are incompletely understood. To model AD-relevant neurodegeneration driven by tau, we overexpressed non-mutated human tau in primary mouse neurons and observed substantial axonal degeneration and cell death, a process accompanied by activated caspase 3. Mechanistically, we detected deformation of the nuclear envelope and increased DNA damage response in tau-expressing neurons. Gene profiling analysis further revealed significant alterations in the mitogen-activated protein kinase (MAPK) pathway; moreover, inhibitors of dual leucine zipper kinase (DLK) and c-Jun N-terminal kinase (JNK) were effective in alleviating wild-type human tau-induced neurodegeneration. In contrast, mutant P301L human tau was less toxic to neurons, despite causing comparable DNA damage. Axonal DLK activation induced by wild-type tau potentiated the impact of DNA damage response, resulting in overt neurotoxicity. In summary, we have established a cellular tauopathy model highly relevant to AD and identified a functional synergy between the DLK-MAPK axis and DNA damage response in the neuronal degenerative process.
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Affiliation(s)
- Sanming Li
- Department of Anesthesiology, Critical Care and Pain Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Ethan R Roy
- Department of Anesthesiology, Critical Care and Pain Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Yanyu Wang
- Department of Anesthesiology, Critical Care and Pain Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Trent Watkins
- Department of Neurology, University of California, San Francisco, CA, 94158, USA
| | - Wei Cao
- Department of Anesthesiology, Critical Care and Pain Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
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2
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Tsering W, Prokop S. Neuritic Plaques - Gateways to Understanding Alzheimer's Disease. Mol Neurobiol 2024; 61:2808-2821. [PMID: 37940777 PMCID: PMC11043180 DOI: 10.1007/s12035-023-03736-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 10/21/2023] [Indexed: 11/10/2023]
Abstract
Extracellular deposits of amyloid-β (Aβ) in the form of plaques are one of the main pathological hallmarks of Alzheimer's disease (AD). Over the years, many different Aβ plaque morphologies such as neuritic plaques, dense cored plaques, cotton wool plaques, coarse-grain plaques, and diffuse plaques have been described in AD postmortem brain tissues, but correlation of a given plaque type with AD progression or AD symptoms is not clear. Furthermore, the exact trigger causing the development of one Aβ plaque morphological subtype over the other is still unknown. Here, we review the current knowledge about neuritic plaques, a subset of Aβ plaques surrounded by swollen or dystrophic neurites, which represent the most detrimental and consequential Aβ plaque morphology. Neuritic plaques have been associated with local immune activation, neuronal network dysfunction, and cognitive decline. Given that neuritic plaques are at the interface of Aβ deposition, tau aggregation, and local immune activation, we argue that understanding the exact mechanism of neuritic plaque formation is crucial to develop targeted therapies for AD.
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Affiliation(s)
- Wangchen Tsering
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, USA
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, USA
- McKnight Brain Institute, University of Florida, Gainesville, USA
| | - Stefan Prokop
- Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, USA.
- McKnight Brain Institute, University of Florida, Gainesville, USA.
- Department of Pathology, University of Florida, Gainesville, USA.
- Fixel Institute for Neurological Diseases, University of Florida, Gainesville, USA.
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3
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Orlowski A, Karippaparambil J, Paumier JM, Ghanta S, Pallares E, Tandukar J, Gao R, Gowrishankar S. Axonal organelle buildup from loss of AP-4 complex function causes exacerbation of amyloid plaque pathology and gliosis in Alzheimer's disease mouse model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.31.587499. [PMID: 38617351 PMCID: PMC11014495 DOI: 10.1101/2024.03.31.587499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Lysosomes and related precursor organelles robustly build up in swollen axons that surround amyloid plaques and disrupted axonal lysosome transport has been implicated in worsening Alzheimer's pathology. Our prior studies have revealed that loss of Adaptor protein-4 (AP-4) complex function, linked primarily to Spastic Paraplegia (HSP), leads to a similar build of lysosomes in structures we term "AP-4 dystrophies". Surprisingly, these AP-4 dystrophies were also characterized by enrichment of components of APP processing machinery, β-site cleaving enzyme 1 (BACE1) and Presenilin 2. Our studies examining whether the abnormal axonal lysosome build up resulting from AP-4 loss could lead to amyloidogenesis revealed that the loss of AP-4 complex function in an Alzheimer's disease model resulted in a strong increase in size and abundance of amyloid plaques in the hippocampus and corpus callosum as well as increased microglial association with the plaques. Interestingly, we found a further increase in enrichment of the secretase, BACE1, in the axonal swellings of the plaques of Alzheimer model mice lacking AP-4 complex compared to those having normal AP-4 complex function, suggestive of increased amyloidogenic processing under this condition. Additionally, the exacerbation of plaque pathology was region-specific as it did not increase in the cortex. The burden of the AP-4 linked axonal dystrophies/AP-4 dystrophies was higher in the corpus callosum and hippocampus compared to the cortex, establishing the critical role of AP-4 -dependent axonal lysosome transport and maturation in regulating amyloidogenic amyloid precursor protein processing.
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Affiliation(s)
- Alex Orlowski
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, Chicago, IL 60612 USA
| | - Joseph Karippaparambil
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, Chicago, IL 60612 USA
| | - Jean-Michel Paumier
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, Chicago, IL 60612 USA
| | - Shraddha Ghanta
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, Chicago, IL 60612 USA
| | - Eduardo Pallares
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, Chicago, IL 60612 USA
| | - Jamuna Tandukar
- Department of Biological Sciences, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, IL 60607 USA
| | - Ruixuan Gao
- Department of Biological Sciences, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, IL 60607 USA
- Department of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, IL 60607 USA
| | - Swetha Gowrishankar
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, Chicago, IL 60612 USA
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4
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Almeida VN. Somatostatin and the pathophysiology of Alzheimer's disease. Ageing Res Rev 2024; 96:102270. [PMID: 38484981 DOI: 10.1016/j.arr.2024.102270] [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: 07/18/2023] [Revised: 03/09/2024] [Accepted: 03/09/2024] [Indexed: 03/28/2024]
Abstract
Among the central features of Alzheimer's disease (AD) progression are altered levels of the neuropeptide somatostatin (SST), and the colocalisation of SST-positive interneurons (SST-INs) with amyloid-β plaques, leading to cell death. In this theoretical review, I propose a molecular model for the pathogenesis of AD based on SST-IN hypofunction and hyperactivity. Namely, hypofunctional and hyperactive SST-INs struggle to control hyperactivity in medial regions in early stages, leading to axonal Aβ production through excessive presynaptic GABAB inhibition, GABAB1a/APP complex downregulation and internalisation. Concomitantly, excessive SST-14 release accumulates near SST-INs in the form of amyloids, which bind to Aβ to form toxic mixed oligomers. This leads to differential SST-IN death through excitotoxicity, further disinhibition, SST deficits, and increased Aβ release, fibrillation and plaque formation. Aβ plaques, hyperactive networks and SST-IN distributions thereby tightly overlap in the brain. Conversely, chronic stimulation of postsynaptic SST2/4 on gulutamatergic neurons by hyperactive SST-INs promotes intense Mitogen-Activated Protein Kinase (MAPK) p38 activity, leading to somatodendritic p-tau staining and apoptosis/neurodegeneration - in agreement with a near complete overlap between p38 and neurofibrillary tangles. This model is suitable to explain some of the principal risk factors and markers of AD progression, including mitochondrial dysfunction, APOE4 genotype, sex-dependent vulnerability, overactive glial cells, dystrophic neurites, synaptic/spine losses, inter alia. Finally, the model can also shed light on qualitative aspects of AD neuropsychology, especially within the domains of spatial and declarative (episodic, semantic) memory, under an overlying pattern of contextual indiscrimination, ensemble instability, interference and generalisation.
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Affiliation(s)
- Victor N Almeida
- Institute of Psychiatry, Faculty of Medicine, University of São Paulo (USP), Brazil; Faculty of Languages, Federal University of Minas Gerais (UFMG), Brazil.
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5
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Tsering W, Hery GP, Phillips JL, Lolo K, Bathe T, Villareal JA, Ruan IY, Prokop S. Transformation of non-neuritic into neuritic plaques during AD progression drives cortical spread of tau pathology via regenerative failure. Acta Neuropathol Commun 2023; 11:190. [PMID: 38037144 PMCID: PMC10691154 DOI: 10.1186/s40478-023-01688-6] [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: 11/08/2023] [Accepted: 11/10/2023] [Indexed: 12/02/2023] Open
Abstract
Extracellular amyloid-β (Aβ) plaques and intracellular aggregates of tau protein in form of neurofibrillary tangles (NFT) are pathological hallmarks of Alzheimer's disease (AD). The exact mechanism how these two protein aggregates interact in AD is still a matter of debate. Neuritic plaques (NP), a subset of Aβ plaques containing dystrophic neurites (DN), are suggested to be unique to AD and might play a role in the interaction of Aβ and tau. Quantifying NP and non-NP in postmortem brain specimens from patients with increasing severity of AD neuropathological changes (ADNC), we demonstrate that the total number of Aβ plaques and NP increase, while the number of non-NP stagnates. Furthermore, investigating the correlation between NP and NFT, we identified unexpected brain region-specific differences when comparing cases with increasingly more severe ADNC. In neocortical regions NFT counts increase in parallel with NP counts during the progression of ADNC, while this correlation is not observed in hippocampus. These data support the notion that non-NP are transformed into NP during the progression of ADNC and indicate that NP might drive cortical NFT formation. Next, using spatial transcriptomics, we analyzed the gene expression profile of the microenvironment around non-NP and NP. We identified an upregulation of neuronal systems and Ca-dependent event pathways around NP compared to non-NP. We speculate that the upregulation of these transcripts may hint at a compensatory mechanism underlying NP formation. Our studies suggest that the transformation of non-NP to NP is a key event in ADNC progression and points to regenerative failure as a potential driving force of this process.
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Affiliation(s)
- Wangchen Tsering
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, USA
- College of Medicine, Mcknight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Gabriela P Hery
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA
- Department of Pathology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Jennifer L Phillips
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA
- Department of Pathology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Kiara Lolo
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Tim Bathe
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA
- Department of Pathology, College of Medicine, University of Florida, Gainesville, FL, USA
- College of Medicine, Mcknight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Jonathan A Villareal
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Isabelle Y Ruan
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Stefan Prokop
- Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, USA.
- Department of Pathology, College of Medicine, University of Florida, Gainesville, FL, USA.
- College of Medicine, Mcknight Brain Institute, University of Florida, Gainesville, FL, USA.
- Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, USA.
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6
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Li S, Roy ER, Wang Y, Watkins T, Cao W. Modeling Alzheimer's disease in primary neurons reveals DNA damage response coupled with MAPK-DLK signaling in wild-type tau-induced neurodegeneration. RESEARCH SQUARE 2023:rs.3.rs-2617457. [PMID: 36945524 PMCID: PMC10029119 DOI: 10.21203/rs.3.rs-2617457/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: 03/09/2023]
Abstract
Background Alzheimer's disease (AD) is the most prevalent form of neurodegeneration. Despite the well-established link between tau aggregation and clinical progression, the major pathways driven by this protein to intrinsically damage neurons are incompletely understood. Methods To model AD-relevant neurodegeneration driven by tau, we overexpressed wild-type human tau in primary mouse neurons and characterized the subsequent cellular and molecular changes. RNAseq profiling and functional investigation were performed as well. A direct comparison with a mutant human tau was conducted in detail. Results We observed substantial axonal degeneration and cell death associated with wild-type tau, a process accompanied by activated caspase 3. Mechanistically, we detected deformation of the nuclear envelope and increased DNA damage response in tau-expressing neurons. Gene profiling analysis further revealed significant alterations in the mitogen-activated protein kinase (MAPK) pathway; moreover, inhibitors of dual leucine zipper kinase (DLK) and c-Jun N-terminal kinase (JNK) were effective in alleviating wild-type human tau-induced neurodegeneration. In contrast, mutant P301L human tau was less toxic to neurons, despite causing comparable DNA damage. Axonal DLK activation induced by wild-type tau potentiated the impact of DNA damage response, resulting in overt neurotoxicity. Conclusions We have established a cellular tauopathy model highly relevant to AD and identified a functional synergy between DNA damage response and the MAPK-DLK axis in the neuronal degenerative process.
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Affiliation(s)
- Sanming Li
- Department of Anesthesiology, Critical Care and Pain Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ethan R Roy
- Department of Anesthesiology, Critical Care and Pain Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Yanyu Wang
- Department of Anesthesiology, Critical Care and Pain Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Trent Watkins
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA. Current address: Department of Neurology, University of California at San Francisco, San Francisco, CA 94158 USA
| | - Wei Cao
- Department of Anesthesiology, Critical Care and Pain Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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7
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Sanchez-Varo R, Sanchez-Mejias E, Fernandez-Valenzuela JJ, De Castro V, Mejias-Ortega M, Gomez-Arboledas A, Jimenez S, Sanchez-Mico MV, Trujillo-Estrada L, Moreno-Gonzalez I, Baglietto-Vargas D, Vizuete M, Davila JC, Vitorica J, Gutierrez A. Plaque-Associated Oligomeric Amyloid-Beta Drives Early Synaptotoxicity in APP/PS1 Mice Hippocampus: Ultrastructural Pathology Analysis. Front Neurosci 2021; 15:752594. [PMID: 34803589 PMCID: PMC8600261 DOI: 10.3389/fnins.2021.752594] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 10/04/2021] [Indexed: 01/14/2023] Open
Abstract
Alzheimer’s disease (AD) is a devastating neurodegenerative disorder characterized by initial memory impairments that progress to dementia. In this sense, synaptic dysfunction and loss have been established as the pathological features that best correlate with the typical early cognitive decline in this disease. At the histopathological level, post mortem AD brains typically exhibit intraneuronal neurofibrillary tangles (NFTs) along with the accumulation of amyloid-beta (Abeta) peptides in the form of extracellular deposits. Specifically, the oligomeric soluble forms of Abeta are considered the most synaptotoxic species. In addition, neuritic plaques are Abeta deposits surrounded by activated microglia and astroglia cells together with abnormal swellings of neuronal processes named dystrophic neurites. These periplaque aberrant neurites are mostly presynaptic elements and represent the first pathological indicator of synaptic dysfunction. In terms of losing synaptic proteins, the hippocampus is one of the brain regions most affected in AD patients. In this work, we report an early decline in spatial memory, along with hippocampal synaptic changes, in an amyloidogenic APP/PS1 transgenic model. Quantitative electron microscopy revealed a spatial synaptotoxic pattern around neuritic plaques with significant loss of periplaque synaptic terminals, showing rising synapse loss close to the border, especially in larger plaques. Moreover, dystrophic presynapses were filled with autophagic vesicles in detriment of the presynaptic vesicular density, probably interfering with synaptic function at very early synaptopathological disease stages. Electron immunogold labeling showed that the periphery of amyloid plaques, and the associated dystrophic neurites, was enriched in Abeta oligomers supporting an extracellular location of the synaptotoxins. Finally, the incubation of primary neurons with soluble fractions derived from 6-month-old APP/PS1 hippocampus induced significant loss of synaptic proteins, but not neuronal death. Indeed, this preclinical transgenic model could serve to investigate therapies targeted at initial stages of synaptic dysfunction relevant to the prodromal and early AD.
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Affiliation(s)
- Raquel Sanchez-Varo
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento Fisiologia Humana, Histologia Humana, Anatomia Patologica y Educacion Fisica y Deportiva, Facultad de Medicina, Universidad de Málaga, Málaga, Spain
| | - Elisabeth Sanchez-Mejias
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Juan Jose Fernandez-Valenzuela
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Vanessa De Castro
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Marina Mejias-Ortega
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Angela Gomez-Arboledas
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Sebastian Jimenez
- Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain.,Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocio CSIC/Universidad de Sevilla, Seville, Spain
| | - Maria Virtudes Sanchez-Mico
- Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain.,Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocio CSIC/Universidad de Sevilla, Seville, Spain
| | - Laura Trujillo-Estrada
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Ines Moreno-Gonzalez
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Department of Neurology, McGovern Medical School, UTHealth Science Center at Houston, Houston, TX, United States
| | - David Baglietto-Vargas
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Marisa Vizuete
- Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain.,Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocio CSIC/Universidad de Sevilla, Seville, Spain
| | - Jose Carlos Davila
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Javier Vitorica
- Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain.,Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocio CSIC/Universidad de Sevilla, Seville, Spain
| | - Antonia Gutierrez
- Departamento Biologia Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.,Centro de Investigación Biomedica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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8
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Shibasaki Y, Maeda N, Oshimi C, Shirakawa Y, Saito M. Quantifying scaling exponents for neurite morphology of in vitro-cultured human iPSC-derived neurons using discrete Loewner evolution: A statistical-physical approach to the neuropathology in Alzheimer's disease. CHAOS (WOODBURY, N.Y.) 2021; 31:073140. [PMID: 34340345 DOI: 10.1063/5.0048559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/02/2021] [Indexed: 06/13/2023]
Abstract
Defining the morphological disorders causing neurodegenerative diseases is an unresolved problem. In this study, we propose a statistical-physical approach to quantify neurite morphology and evaluate the pathological states induced by Alzheimer's disease (AD). We analyzed the two-dimensional morphologies of neurites of in vitro-cultured human induced-pluripotent stem cell-derived neurons, reprogrammed from both a healthy person and a patient with AD, using discrete chordal Loewner evolution. For the numerically calculated Loewner driving forces, detrended fluctuation analysis was performed, and the morphological characteristics of the neurites were quantified using short-range and long-range scaling exponents. The day in vitro (DIV)-dependent behaviors of the scaling exponents and the associated neurite-type categorizations suggested that differences between healthy and AD neurites can be observed from the early stage (DIV3) of their development. Notably, AD neurites have less long-range autocorrelations than healthy neurites, particularly in the earlier stages (DIV3-10). Immunofluorescence-staining results suggested that these differences precede significant expressions of β-amyloid and phosphorylated tau, which are known as biological factors causing AD. We expect that these results will lead to a theoretical interpretation of the neurogenerative disease, providing the physical properties of individual neurites with different morphologies.
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Affiliation(s)
- Yusuke Shibasaki
- Department of Correlative Study in Physics and Chemistry, Graduate School of Integrated Basic Sciences, Nihon University, Setagaya, Tokyo 156-8550, Japan
| | - Narumi Maeda
- Department of Correlative Study in Physics and Chemistry, Graduate School of Integrated Basic Sciences, Nihon University, Setagaya, Tokyo 156-8550, Japan
| | - Chihiro Oshimi
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Setagaya, Tokyo 156-8550, Japan
| | - Yuka Shirakawa
- The Institute of Natural Sciences, College of Humanities and Sciences, Nihon University, Setagaya, Tokyo 156-8550, Japan
| | - Minoru Saito
- Department of Correlative Study in Physics and Chemistry, Graduate School of Integrated Basic Sciences, Nihon University, Setagaya, Tokyo 156-8550, Japan
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9
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Edmison D, Wang L, Gowrishankar S. Lysosome Function and Dysfunction in Hereditary Spastic Paraplegias. Brain Sci 2021; 11:152. [PMID: 33498913 PMCID: PMC7911997 DOI: 10.3390/brainsci11020152] [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: 12/21/2020] [Revised: 01/15/2021] [Accepted: 01/21/2021] [Indexed: 12/13/2022] Open
Abstract
Hereditary Spastic Paraplegias (HSPs) are a genetically diverse group of inherited neurological diseases with over 80 associated gene loci. Over the last decade, research into mechanisms underlying HSPs has led to an emerging interest in lysosome dysfunction. In this review, we highlight the different classes of HSPs that have been linked to lysosome defects: (1) a subset of complex HSPs where mutations in lysosomal genes are causally linked to the diseases, (2) other complex HSPs where mutation in genes encoding membrane trafficking adaptors lead to lysosomal defects, and (3) a subset of HSPs where mutations affect genes encoding proteins whose function is primarily linked to a different cellular component or organelle such as microtubule severing and Endoplasmic Reticulum-shaping, while also altering to lysosomes. Interestingly, aberrant axonal lysosomes, associated with the latter two subsets of HSPs, are a key feature observed in other neurodegenerative diseases such as Alzheimer's disease. We discuss how altered lysosome function and trafficking may be a critical contributor to HSP pathology and highlight the need for examining these features in the cortico-spinal motor neurons of HSP mutant models.
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Affiliation(s)
| | | | - Swetha Gowrishankar
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA; (D.E.); (L.W.)
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10
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Shi YB, Tu T, Jiang J, Zhang QL, Ai JQ, Pan A, Manavis J, Tu E, Yan XX. Early Dendritic Dystrophy in Human Brains With Primary Age-Related Tauopathy. Front Aging Neurosci 2020; 12:596894. [PMID: 33364934 PMCID: PMC7750631 DOI: 10.3389/fnagi.2020.596894] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 11/06/2020] [Indexed: 12/15/2022] Open
Abstract
Dystrophic neurites (DNs) are found in many neurological conditions such as traumatic brain injury and age-related neurodegenerative diseases. In Alzheimer's disease (AD) specifically, senile plaques containing silver-stained DNs were already described in the original literature defining this disease. These DNs could be both axonal and dendritic in origin, while axonal dystrophy relative to plaque formation has been more extensively studied. Here, we demonstrate an early occurrence of dendritic dystrophy in the hippocampal CA1 and subicular regions in human brains (n = 23) with primary age-related tauopathy (PART), with neurofibrillary tangle (NFT) burden ranging from Braak stages I to III in the absence of cerebral β-amyloid (Aβ) deposition. In Bielschowsky's silver stain, segmented fusiform swellings on the apical dendrites of hippocampal and subicular pyramidal neurons were observed in all the cases, primarily over the stratum radiatum (s.r.). The numbers of silver-stained neuronal somata and dendritic swellings counted over CA1 to subiculum were positively correlated among the cases. Swollen dendritic processes were also detected in sections immunolabeled for phosphorylated tau (pTau) and sortilin. In aged and AD brains with both Aβ and pTau pathologies, silver- and immunolabeled dystrophic-like dendritic profiles occurred around and within individual neuritic plaques. These findings implicate that dendritic dystrophy can occur among hippocampal pyramidal neurons in human brains with PART. Therefore, as with the case of axonal dystrophy reported in literature, dendritic dystrophy can develop prior to Alzheimer-type plaque and tangle formation in the human brain.
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Affiliation(s)
- Yan-Bin Shi
- Medical Doctor Program, Xiangya School of Medicine, Central South University, Changsha, China
| | - Tian Tu
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Juan Jiang
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Qi-Lei Zhang
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Jia-Qi Ai
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Aihua Pan
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Jim Manavis
- Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Ewen Tu
- Department of Neurology, Brain Hospital of Hunan Province, Changsha, China
| | - Xiao-Xin Yan
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
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11
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Tran HT, Tsai EHR, Lewis AJ, Moors T, Bol JGJM, Rostami I, Diaz A, Jonker AJ, Guizar-Sicairos M, Raabe J, Stahlberg H, van de Berg WDJ, Holler M, Shahmoradian SH. Alterations in Sub-Axonal Architecture Between Normal Aging and Parkinson's Diseased Human Brains Using Label-Free Cryogenic X-ray Nanotomography. Front Neurosci 2020; 14:570019. [PMID: 33324142 PMCID: PMC7724048 DOI: 10.3389/fnins.2020.570019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/14/2020] [Indexed: 01/25/2023] Open
Abstract
Gaining insight to pathologically relevant processes in continuous volumes of unstained brain tissue is important for a better understanding of neurological diseases. Many pathological processes in neurodegenerative disorders affect myelinated axons, which are a critical part of the neuronal circuitry. Cryo ptychographic X-ray computed tomography in the multi-keV energy range is an emerging technology providing phase contrast at high sensitivity, allowing label-free and non-destructive three dimensional imaging of large continuous volumes of tissue, currently spanning up to 400,000 μm3. This aspect makes the technique especially attractive for imaging complex biological material, especially neuronal tissues, in combination with downstream optical or electron microscopy techniques. A further advantage is that dehydration, additional contrast staining, and destructive sectioning/milling are not required for imaging. We have developed a pipeline for cryo ptychographic X-ray tomography of relatively large, hydrated and unstained biological tissue volumes beyond what is typical for the X-ray imaging, using human brain tissue and combining the technique with complementary methods. We present four imaged volumes of a Parkinson's diseased human brain and five volumes from a non-diseased control human brain using cryo ptychographic X-ray tomography. In both cases, we distinguish neuromelanin-containing neurons, lipid and melanic pigment, blood vessels and red blood cells, and nuclei of other brain cells. In the diseased sample, we observed several swellings containing dense granular material resembling clustered vesicles between the myelin sheaths arising from the cytoplasm of the parent oligodendrocyte, rather than the axoplasm. We further investigated the pathological relevance of such swollen axons in adjacent tissue sections by immunofluorescence microscopy for phosphorylated alpha-synuclein combined with multispectral imaging. Since cryo ptychographic X-ray tomography is non-destructive, the large dataset volumes were used to guide further investigation of such swollen axons by correlative electron microscopy and immunogold labeling post X-ray imaging, a possibility demonstrated for the first time. Interestingly, we find that protein antigenicity and ultrastructure of the tissue are preserved after the X-ray measurement. As many pathological processes in neurodegeneration affect myelinated axons, our work sets an unprecedented foundation for studies addressing axonal integrity and disease-related changes in unstained brain tissues.
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Affiliation(s)
| | | | - Amanda J. Lewis
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, Basel, Switzerland
| | - Tim Moors
- Department of Anatomy and Neurosciences, Section Clinical Neuroanatomy, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - J. G. J. M. Bol
- Department of Anatomy and Neurosciences, Section Clinical Neuroanatomy, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | | | - Ana Diaz
- Paul Scherrer Institut, Villigen, Switzerland
| | - Allert J. Jonker
- Department of Anatomy and Neurosciences, Section Clinical Neuroanatomy, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | | | - Joerg Raabe
- Paul Scherrer Institut, Villigen, Switzerland
| | - Henning Stahlberg
- Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel, Basel, Switzerland
| | - Wilma D. J. van de Berg
- Department of Anatomy and Neurosciences, Section Clinical Neuroanatomy, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
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12
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Salvadores N, Gerónimo-Olvera C, Court FA. Axonal Degeneration in AD: The Contribution of Aβ and Tau. Front Aging Neurosci 2020; 12:581767. [PMID: 33192476 PMCID: PMC7593241 DOI: 10.3389/fnagi.2020.581767] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/09/2020] [Indexed: 12/25/2022] Open
Abstract
Alzheimer's disease (AD) represents the most common age-related neurodegenerative disorder, affecting around 35 million people worldwide. Despite enormous efforts dedicated to AD research over decades, there is still no cure for the disease. Misfolding and accumulation of Aβ and tau proteins in the brain constitute a defining signature of AD neuropathology, and mounting evidence has documented a link between aggregation of these proteins and neuronal dysfunction. In this context, progressive axonal degeneration has been associated with early stages of AD and linked to Aβ and tau accumulation. As the axonal degeneration mechanism has been starting to be unveiled, it constitutes a promising target for neuroprotection in AD. A comprehensive understanding of the mechanism of axonal destruction in neurodegenerative conditions is therefore critical for the development of new therapies aimed to prevent axonal loss before irreversible neuronal death occurs in AD. Here, we review current evidence of the involvement of Aβ and tau pathologies in the activation of signaling cascades that can promote axonal demise.
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Affiliation(s)
- Natalia Salvadores
- Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile.,Fondap Geroscience Center for Brain Health and Metabolism, Santiago, Chile
| | - Cristian Gerónimo-Olvera
- Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile.,Fondap Geroscience Center for Brain Health and Metabolism, Santiago, Chile
| | - Felipe A Court
- Center for Integrative Biology, Faculty of Sciences, Universidad Mayor, Santiago, Chile.,Fondap Geroscience Center for Brain Health and Metabolism, Santiago, Chile.,Buck Institute for Research on Aging, Novato, CA, United States
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13
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Sos KE, Mayer MI, Takács VT, Major A, Bardóczi Z, Beres BM, Szeles T, Saito T, Saido TC, Mody I, Freund TF, Nyiri G. Amyloid β induces interneuron-specific changes in the hippocampus of APPNL-F mice. PLoS One 2020; 15:e0233700. [PMID: 32469963 PMCID: PMC7259556 DOI: 10.1371/journal.pone.0233700] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 05/11/2020] [Indexed: 01/07/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline and amyloid-beta (Aβ) depositions generated by the proteolysis of amyloid precursor protein (APP) in the brain. In APPNL-F mice, APP gene was humanized and contains two familial AD mutations, and APP-unlike other mouse models of AD-is driven by the endogenous mouse APP promoter. Similar to people without apparent cognitive dysfunction but with heavy Aβ plaque load, we found no significant decline in the working memory of adult APPNL-F mice, but these mice showed decline in the expression of normal anxiety. Using immunohistochemistry and 3D block-face scanning electron microscopy, we found no changes in GABAA receptor positivity and size of somatic and dendritic synapses of hippocampal interneurons. We did not find alterations in the level of expression of perineuronal nets around parvalbumin (PV) interneurons or in the density of PV- or somatostatin-positive hippocampal interneurons. However, in contrast to other investigated cell types, PV interneuron axons were occasionally mildly dystrophic around Aβ plaques, and the synapses of PV-positive axon initial segment (AIS)-targeting interneurons were significantly enlarged. Our results suggest that PV interneurons are highly resistant to amyloidosis in APPNL-F mice and amyloid-induced increase in hippocampal pyramidal cell excitability may be compensated by PV-positive AIS-targeting cells. Mechanisms that make PV neurons more resilient could therefore be exploited in the treatment of AD for mitigating Aβ-related inflammatory effects on neurons.
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Affiliation(s)
- Katalin E. Sos
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Márton I. Mayer
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Virág T. Takács
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
| | - Abel Major
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
| | - Zsuzsanna Bardóczi
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
| | - Barnabas M. Beres
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
| | - Tamás Szeles
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN, Center for Brain Science, Saitama, Japan
- Department of Neurocognitive Science, Nagoya City University Graduate School of Medical Science, Aichi, Japan
| | - Takaomi C. Saido
- Laboratory for Proteolytic Neuroscience, RIKEN, Center for Brain Science, Saitama, Japan
| | - István Mody
- Department of Neurology, University of California, Los Angeles, California, United States of America
| | - Tamás F. Freund
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
| | - Gábor Nyiri
- Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, HAS, Budapest, Hungary
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14
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Tripathi A, Choubey PK, Sharma P, Seth A, Tripathi PN, Tripathi MK, Prajapati SK, Krishnamurthy S, Shrivastava SK. Design and development of molecular hybrids of 2-pyridylpiperazine and 5-phenyl-1,3,4-oxadiazoles as potential multifunctional agents to treat Alzheimer's disease. Eur J Med Chem 2019; 183:111707. [DOI: 10.1016/j.ejmech.2019.111707] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 09/14/2019] [Accepted: 09/15/2019] [Indexed: 01/04/2023]
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15
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Malik BR, Maddison DC, Smith GA, Peters OM. Autophagic and endo-lysosomal dysfunction in neurodegenerative disease. Mol Brain 2019; 12:100. [PMID: 31783880 PMCID: PMC6884906 DOI: 10.1186/s13041-019-0504-x] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 10/01/2019] [Indexed: 12/11/2022] Open
Abstract
Due to their post-mitotic state, metabolic demands and often large polarised morphology, the function and survival of neurons is dependent on an efficient cellular waste clearance system both for generation of materials for metabolic processes and removal of toxic components. It is not surprising therefore that deficits in protein clearance can tip the balance between neuronal health and death. Here we discuss how autophagy and lysosome-mediated degradation pathways are disrupted in several neurological disorders. Both genetic and cell biological evidence show the diversity and complexity of vesicular clearance dysregulation in cells, and together may ultimately suggest a unified mechanism for neuronal demise in degenerative conditions. Causative and risk-associated mutations in Alzheimer's disease, Frontotemporal Dementia, Amyotrophic Lateral Sclerosis, Parkinson's disease, Huntington's disease and others have given the field a unique mechanistic insight into protein clearance processes in neurons. Through their broad implication in neurodegenerative diseases, molecules involved in these genetic pathways, in particular those involved in autophagy, are emerging as appealing therapeutic targets for intervention in neurodegeneration.
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Affiliation(s)
- Bilal R Malik
- UK Dementia Research Institute at Cardiff University, Cardiff, Wales, UK
- School of Biosciences, Cardiff University, Cardiff, Wales, UK
| | - Daniel C Maddison
- UK Dementia Research Institute at Cardiff University, Cardiff, Wales, UK
- School of Medicine, Cardiff University, Cardiff, Wales, UK
| | - Gaynor A Smith
- UK Dementia Research Institute at Cardiff University, Cardiff, Wales, UK.
- School of Medicine, Cardiff University, Cardiff, Wales, UK.
| | - Owen M Peters
- UK Dementia Research Institute at Cardiff University, Cardiff, Wales, UK.
- School of Biosciences, Cardiff University, Cardiff, Wales, UK.
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16
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E L, Zhou T, Koh S, Chuang M, Sharma R, Pujol N, Chisholm AD, Eroglu C, Matsunami H, Yan D. An Antimicrobial Peptide and Its Neuronal Receptor Regulate Dendrite Degeneration in Aging and Infection. Neuron 2019; 97:125-138.e5. [PMID: 29301098 DOI: 10.1016/j.neuron.2017.12.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 10/09/2017] [Accepted: 11/30/2017] [Indexed: 01/01/2023]
Abstract
Infections have been identified as possible risk factors for aging-related neurodegenerative diseases, but it remains unclear whether infection-related immune molecules have a causative role in neurodegeneration during aging. Here, we reveal an unexpected role of an epidermally expressed antimicrobial peptide, NLP-29 (neuropeptide-like protein 29), in triggering aging-associated dendrite degeneration in C. elegans. The age-dependent increase of nlp-29 expression is regulated by the epidermal tir-1/SARM-pmk-1/p38 MAPK innate immunity pathway. We further identify an orphan G protein-coupled receptor NPR-12 (neuropeptide receptor 12) acting in neurons as a receptor for NLP-29 and demonstrate that the autophagic machinery is involved cell autonomously downstream of NPR-12 to transduce degeneration signals. Finally, we show that fungal infections cause dendrite degeneration using a similar mechanism as in aging, through NLP-29, NPR-12, and autophagy. Our findings reveal an important causative role of antimicrobial peptides, their neuronal receptors, and the autophagy pathway in aging- and infection-associated dendrite degeneration.
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Affiliation(s)
- Lezi E
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ting Zhou
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Sehwon Koh
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Marian Chuang
- Section of Neurobiology and Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ruchira Sharma
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Nathalie Pujol
- Centre d'Immunologie de Marseille-Luminy, CIML, Aix Marseille Université, Inserm, CNRS, Marseille 13288, France
| | - Andrew D Chisholm
- Section of Neurobiology and Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology and Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology and Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Dong Yan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology and Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC 27710, USA.
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17
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Chen XQ, Mobley WC. Alzheimer Disease Pathogenesis: Insights From Molecular and Cellular Biology Studies of Oligomeric Aβ and Tau Species. Front Neurosci 2019; 13:659. [PMID: 31293377 PMCID: PMC6598402 DOI: 10.3389/fnins.2019.00659] [Citation(s) in RCA: 176] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 06/07/2019] [Indexed: 01/08/2023] Open
Abstract
Alzheimer disease (AD) represents an oncoming epidemic that without an effective treatment promises to exact extraordinary human and financial burdens. Studies of pathogenesis are essential for defining targets for discovering disease-modifying treatments. Past studies of AD neuropathology provided valuable, albeit limited, insights. Nevertheless, building on these findings, recent studies have provided an increasingly rich harvest of genetic, molecular and cellular data that are creating unprecedented opportunities to both understand and treat AD. Among the most significant are those documenting the presence within the AD brain of toxic oligomeric species of Aβ and tau. Existing data support the view that such species can propagate and spread within neural circuits. To place these findings in context we first review the genetics and neuropathology of AD, including AD in Down syndrome (AD-DS). We detail studies that support the existence of toxic oligomeric species while noting the significant unanswered questions concerning their precise structures, the means by which they spread and undergo amplification and how they induce neuronal dysfunction and degeneration. We conclude by offering a speculative synthesis for how oligomers of Aβ and tau initiate and drive pathogenesis. While 100 years after Alzheimer's first report there is much still to learn about pathogenesis and the discovery of disease-modifying treatments, the application of new concepts and sophisticated new tools are poised to deliver important advances for combatting AD.
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Affiliation(s)
- Xu-Qiao Chen
- Department of Neurosciences, University of California, San Diego, San Diego, CA, United States
| | - William C. Mobley
- Department of Neurosciences, University of California, San Diego, San Diego, CA, United States
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18
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Early alterations in hippocampal perisomatic GABAergic synapses and network oscillations in a mouse model of Alzheimer's disease amyloidosis. PLoS One 2019; 14:e0209228. [PMID: 30645585 PMCID: PMC6333398 DOI: 10.1371/journal.pone.0209228] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/30/2018] [Indexed: 01/01/2023] Open
Abstract
Several lines of evidence imply changes in inhibitory interneuron connectivity and subsequent alterations in oscillatory network activities in the pathogenesis of Alzheimer’s Disease (AD). Recently, we provided evidence for an increased immunoreactivity of both the postsynaptic scaffold protein gephyrin and the GABAA receptor γ2-subunit in the hippocampus of young (1 and 3 months of age), APPPS1 mice. These mice represent a well-established model of cerebral amyloidosis, which is a hallmark of human AD. In this study, we demonstrate a robust increase of parvalbumin immunoreactivity and accentuated projections of parvalbumin positive (PV+) interneurons, which target perisomatic regions of pyramidal cells within the hippocampal subregions CA1 and CA3 of 3-month-old APPPS1 mice. Colocalisation studies confirmed a significant increase in the density of PV+ projections labeled with antibodies against a presynaptic (vesicular GABA transporter) and a postsynaptic marker (gephyrin) of inhibitory synapses within the pyramidal cell layer of CA1 and CA3. As perisomatic inhibition by PV+-interneurons is crucial for the generation of hippocampal network oscillations involved in spatial processing, learning and memory formation we investigated the impact of the putative enhanced perisomatic inhibition on two types of fast neuronal network oscillations in acute hippocampal slices: 1. spontaneously occurring sharp wave-ripple complexes (SPW-R), and 2. cholinergic γ-oscillations. Interestingly, both network patterns were generally preserved in APPPS1 mice similar to WT mice. However, the comparison of simultaneous CA3 and CA1 recordings revealed that the incidence and amplitude of SPW-Rs were significantly lower in CA1 vs CA3 in APPPS1 slices, whereas the power of γ-oscillations was significantly higher in CA3 vs CA1 in WT-slices indicating an impaired communication between the CA3 and CA1 network activities in APPPS1 mice. Taken together, our data demonstrate an increased GABAergic synaptic output of PV+ interneurons impinging on pyramidal cells of CA1 and CA3, which might limit the coordinated cross-talk between these two hippocampal areas in young APPPS1 mice and mediate long-term changes in synaptic inhibition during progression of amyloidosis.
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19
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Nanowired delivery of cerebrolysin with neprilysin and p-Tau antibodies induces superior neuroprotection in Alzheimer's disease. PROGRESS IN BRAIN RESEARCH 2019; 245:145-200. [DOI: 10.1016/bs.pbr.2019.03.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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20
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de la Monte SM. The Full Spectrum of Alzheimer's Disease Is Rooted in Metabolic Derangements That Drive Type 3 Diabetes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1128:45-83. [PMID: 31062325 PMCID: PMC9996398 DOI: 10.1007/978-981-13-3540-2_4] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The standard practice in neuropathology is to diagnose Alzheimer's disease (AD) based on the distribution and abundance of neurofibrillary tangles and Aβ deposits. However, other significant abnormalities including neuroinflammation, gliosis, white matter degeneration, non-Aβ microvascular disease, and insulin-related metabolic dysfunction require further study to understand how they could be targeted to more effectively remediate AD. This review addresses non-Aβ and non-pTau AD-associated pathologies, highlighting their major features, roles in neurodegeneration, and etiopathic links to deficits in brain insulin and insulin-like growth factor signaling and cognitive impairment. The discussion delineates why AD with its most characteristic clinical and pathological phenotypic profiles should be regarded as a brain form of diabetes, i.e., type 3 diabetes, and entertains the hypothesis that type 3 diabetes is just one of the categories of insulin resistance diseases that can occur independently or overlap with one or more of the others, including type 2 diabetes, metabolic syndrome, and nonalcoholic fatty liver disease.
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Affiliation(s)
- Suzanne M de la Monte
- Departments of Neurology, Neuropathology, and Neurosurgery, Rhode Island Hospital, and the Alpert Medical School of Brown University, Providence, RI, USA.
- Department of Pathology and Laboratory Medicine, Providence VA Medical Center, Providence, RI, USA.
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21
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Massimi L, Bukreeva I, Santamaria G, Fratini M, Corbelli A, Brun F, Fumagalli S, Maugeri L, Pacureanu A, Cloetens P, Pieroni N, Fiordaliso F, Forloni G, Uccelli A, Kerlero de Rosbo N, Balducci C, Cedola A. Exploring Alzheimer's disease mouse brain through X-ray phase contrast tomography: From the cell to the organ. Neuroimage 2018; 184:490-495. [PMID: 30240904 DOI: 10.1016/j.neuroimage.2018.09.044] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 09/09/2018] [Accepted: 09/17/2018] [Indexed: 12/14/2022] Open
Abstract
Alzheimer's disease (AD), the most common form of dementia, is a progressive neurodegenerative disorder associated with aberrant production of beta-amyloid (Aβ) peptide depositing in brain as amyloid plaques. While animal models allow investigation of disease progression and therapeutic efficacy, technology to fully dissect the pathological mechanisms of this complex disease at cellular and vascular levels is lacking. X-ray phase contrast tomography (XPCT) is an advanced non-destructive 3D multi-scale direct imaging from the cell through to the whole brain, with exceptional spatial and contrast resolution. We exploit XPCT to simultaneously analyse disease-relevant vascular and neuronal networks in AD mouse brain, without sectioning and staining. The findings clearly show the different typologies and internal structures of Aβ plaques, together with their interaction with patho/physiological cellular and neuro-vascular microenvironment. XPCT enables for the first time a detailed visualization of amyloid-angiopathy at capillary level, which is impossible to achieve with other approaches. XPCT emerges as added-value technology to explore AD mouse brain as a whole, preserving tissue chemistry and structure, enabling the comparison of physiological vs. pathological states at the level of crucial disease targets. In-vivo translation will permit to monitor emerging therapeutic approaches and possibly shed new light on pathological mechanisms of neurodegenerative diseases.
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Affiliation(s)
- Lorenzo Massimi
- Istituto di Nanotecnologia, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Inna Bukreeva
- Istituto di Nanotecnologia, Consiglio Nazionale delle Ricerche, Rome, Italy; Dipartimento di Fisica, Università Sapienza, Rome, Italy
| | | | - Michela Fratini
- Istituto di Nanotecnologia, Consiglio Nazionale delle Ricerche, Rome, Italy; IRCCS Fondazione Santa Lucia, Rome, Italy
| | | | - Francesco Brun
- Istituto di Nanotecnologia, Consiglio Nazionale delle Ricerche, Rome, Italy
| | | | - Laura Maugeri
- Istituto di Nanotecnologia, Consiglio Nazionale delle Ricerche, Rome, Italy; IRCCS Fondazione Santa Lucia, Rome, Italy
| | | | - Peter Cloetens
- European Synchrotron Radiation Facility, Grenoble, France
| | - Nicola Pieroni
- Istituto di Nanotecnologia, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Fabio Fiordaliso
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | | | - Antonio Uccelli
- DINOGMI, Università degli Studi di Genova, Genoa, Italy; Ospedale Policlinico San Martino, Genoa, Italy
| | | | - Claudia Balducci
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy.
| | - Alessia Cedola
- Istituto di Nanotecnologia, Consiglio Nazionale delle Ricerche, Rome, Italy; Dipartimento di Fisica, Università Sapienza, Rome, Italy.
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22
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Schiel KA. A new etiologic model for Alzheimers Disease. Med Hypotheses 2018; 111:27-35. [DOI: 10.1016/j.mehy.2017.12.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 11/19/2017] [Accepted: 12/12/2017] [Indexed: 01/26/2023]
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23
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Schweig JE, Yao H, Beaulieu-Abdelahad D, Ait-Ghezala G, Mouzon B, Crawford F, Mullan M, Paris D. Alzheimer's disease pathological lesions activate the spleen tyrosine kinase. Acta Neuropathol Commun 2017; 5:69. [PMID: 28877763 PMCID: PMC5588676 DOI: 10.1186/s40478-017-0472-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 08/30/2017] [Indexed: 01/17/2023] Open
Abstract
The pathology of Alzheimer’s disease (AD) is characterized by dystrophic neurites (DNs) surrounding extracellular Aβ-plaques, microgliosis, astrogliosis, intraneuronal tau hyperphosphorylation and aggregation. We have previously shown that inhibition of the spleen tyrosine kinase (Syk) lowers Aβ production and tau hyperphosphorylation in vitro and in vivo. Here, we demonstrate that Aβ-overexpressing Tg PS1/APPsw, Tg APPsw mice, and tau overexpressing Tg Tau P301S mice exhibit a pathological activation of Syk compared to wild-type littermates. Syk activation is occurring in a subset of microglia and is age-dependently increased in Aβ-plaque-associated dystrophic neurites of Tg PS1/APPsw and Tg APPsw mice. In Tg Tau P301S mice, a pure model of tauopathy, activated Syk occurs in neurons that show an accumulation of misfolded and hyperphosphorylated tau in the cortex and hippocampus. Interestingly, the tau pathology is exacerbated in neurons that display high levels of Syk activation supporting a role of Syk in the formation of tau pathological species in vivo. Importantly, human AD brain sections show both pathological Syk activation in DNs around Aβ deposits and in neurons immunopositive for pathological tau species recapitulating the data obtained in transgenic mouse models of AD. Additionally, we show that Syk overexpression leads to increased tau accumulation and promotes tau hyperphosphorylation at multiple epitopes in human neuron-like SH-SY5Y cells, further supporting a role of Syk in the formation of tau pathogenic species. Collectively, our data show that Syk activation occurs following Aβ deposition and the formation of tau pathological species. Given that we have previously shown that Syk activation also promotes Aβ formation and tau hyperphosphorylation, our data suggest that AD pathological lesions may be self-propagating via a Syk dependent mechanism highlighting Syk as an attractive therapeutic target for the treatment of AD.
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24
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Gowrishankar S, Wu Y, Ferguson SM. Impaired JIP3-dependent axonal lysosome transport promotes amyloid plaque pathology. J Cell Biol 2017; 216:3291-3305. [PMID: 28784610 PMCID: PMC5626538 DOI: 10.1083/jcb.201612148] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 05/18/2017] [Accepted: 07/06/2017] [Indexed: 12/29/2022] Open
Abstract
Axonal lysosomes accumulate abnormally in Alzheimer’s disease brains. However, whether and how such lysosomes contribute to disease pathology has been unclear. Gowrishankar et al. show that the JIP3-dependent transport of axonal lysosomes negatively regulates amyloid precursor protein processing into amyloidogenic peptides. Lysosomes robustly accumulate within axonal swellings at Alzheimer’s disease (AD) amyloid plaques. However, the underlying mechanisms and disease relevance of such lysosome accumulations are not well understood. Motivated by these problems, we identified JNK-interacting protein 3 (JIP3) as an important regulator of axonal lysosome transport and maturation. JIP3 knockout mouse neuron primary cultures accumulate lysosomes within focal axonal swellings that resemble the dystrophic axons at amyloid plaques. These swellings contain high levels of amyloid precursor protein processing enzymes (BACE1 and presenilin 2) and are accompanied by elevated Aβ peptide levels. The in vivo importance of the JIP3-dependent regulation of axonal lysosomes was revealed by the worsening of the amyloid plaque pathology arising from JIP3 haploinsufficiency in a mouse model of AD. These results establish the critical role of JIP3-dependent axonal lysosome transport in regulating amyloidogenic amyloid precursor protein processing and support a model wherein Aβ production is amplified by plaque-induced axonal lysosome transport defects.
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Affiliation(s)
- Swetha Gowrishankar
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Yumei Wu
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Shawn M Ferguson
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT .,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
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25
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Fessel WJ. Concordance of Several Subcellular Interactions Initiates Alzheimer's Dementia: Their Reversal Requires Combination Treatment. Am J Alzheimers Dis Other Demen 2017; 32:166-181. [PMID: 28423937 PMCID: PMC10852791 DOI: 10.1177/1533317517698790] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The pathogenesis of Alzheimer's disease involves multiple pathways that, at the macrolevel, include decreased proliferation plus increased loss affecting neurons, astrocytes, and capillaries and, at the subcellular level, involve several elements: amyloid/amyloid precursor protein, presenilins, the unfolded protein response, the ubiquitin/proteasome system, the Wnt/catenin system, the Notch signaling system, mitochondria, mitophagy, calcium, and tau. Data presented show the intimate, anatomical interactions between neurons, astrocytes, and capillaries; the interactions between the several subcellular factors affecting those cells; and the treatments that are currently available and that might correct dysfunctions in the subcellular factors. Available treatments include lithium, valproate, pioglitazone, erythropoietin, and prazosin. Since the subcellular pathogenesis involves multiple interacting elements, combination treatment would be more effective than administration of a single drug directed at only 1 element. The overall purpose of this presentation is to describe the pathogenesis in detail and to explain the proposed treatments.
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Affiliation(s)
- W. J. Fessel
- University of California, San Francisco, CA, USA
- Kaiser Permanente Medical Care Program, San Francisco, CA, USA
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26
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Blazquez-Llorca L, Valero-Freitag S, Rodrigues EF, Merchán-Pérez Á, Rodríguez JR, Dorostkar MM, DeFelipe J, Herms J. High plasticity of axonal pathology in Alzheimer's disease mouse models. Acta Neuropathol Commun 2017; 5:14. [PMID: 28173876 PMCID: PMC5296955 DOI: 10.1186/s40478-017-0415-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 01/26/2017] [Indexed: 02/05/2023] Open
Abstract
Axonal dystrophies (AxDs) are swollen and tortuous neuronal processes that are associated with extracellular depositions of amyloid β (Aβ) and have been observed to contribute to synaptic alterations occurring in Alzheimer's disease. Understanding the temporal course of this axonal pathology is of high relevance to comprehend the progression of the disease over time. We performed a long-term in vivo study (up to 210 days of two-photon imaging) with two transgenic mouse models (dE9xGFP-M and APP-PS1xGFP-M). Interestingly, AxDs were formed only in a quarter of GFP-expressing axons near Aβ-plaques, which indicates a selective vulnerability. AxDs, especially those reaching larger sizes, had long lifetimes and appeared as highly plastic structures with large variations in size and shape and axonal sprouting over time. In the case of the APP-PS1 mouse only, the formation of new long axonal segments in dystrophic axons (re-growth phenomenon) was observed. Moreover, new AxDs could appear at the same point of the axon where a previous AxD had been located before disappearance (re-formation phenomenon). In addition, we observed that most AxDs were formed and developed during the imaging period, and numerous AxDs had already disappeared by the end of this time. This work is the first in vivo study analyzing quantitatively the high plasticity of the axonal pathology around Aβ plaques. We hypothesized that a therapeutically early prevention of Aβ plaque formation or their growth might halt disease progression and promote functional axon regeneration and the recovery of neural circuits.
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27
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Uchida Y, Gomi F. The role of calsyntenin-3 in dystrophic neurite formation in Alzheimer's disease brain. Geriatr Gerontol Int 2017; 16 Suppl 1:43-50. [PMID: 27018282 DOI: 10.1111/ggi.12737] [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] [Accepted: 12/22/2015] [Indexed: 11/27/2022]
Abstract
β-Amyloid (Aβ) oligomers may play an important role in the early pathogenesis of Alzheimer's disease: cognitive impairment caused by synaptic dysfunction. Dystrophic neurites surrounding Aβ plaques, another pathological feature of Alzheimer's disease, are plaque-associated neuritic alterations preceding the appearance of synaptic loss. In the present review, we focus on the mechanism of dystrophic neurite formation by Aß oligomers, and discuss the neurotoxic role of Aβ-induced calsyntenin-3 in mediating dystrophic neurite formation.
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Affiliation(s)
- Yoko Uchida
- Research Team for Aging Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Fujiya Gomi
- Research Team for Aging Neuroscience, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
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28
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Li Q, Liu Y, Sun M. Autophagy and Alzheimer's Disease. Cell Mol Neurobiol 2016; 37:377-388. [PMID: 27260250 DOI: 10.1007/s10571-016-0386-8] [Citation(s) in RCA: 219] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 05/24/2016] [Indexed: 01/20/2023]
Abstract
Autophagy is an essential degradation pathway in clearing abnormal protein aggregates in mammalian cells and is responsible for protein homeostasis and neuronal health. Several studies have shown that autophagy deficits occurred in early stage of Alzheimer's disease (AD). Autophagy plays an important role in generation and metabolism of β-amyloid (Aβ), assembling of tau and thus its malfunction may lead to the progress of AD. By considering the above evidences, autophagy may be a new target in developing drugs for AD. So far, a number of mammalian target of rapamycin (mTOR)-dependent and independent autophagy modulators have been identified to have positive effects in AD treatment. In this review, we summarized the latest progress supporting the role for autophagy deficits in AD and the potential therapeutic effects of autophagy modulators in AD.
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Affiliation(s)
- Qian Li
- Neuroscience Research Institute, Peking University, Beijing, China
| | - Yi Liu
- Department of Neurology, Dalian Municipal Central Hospital, Affiliated Hospital of Dalian Medical University, Dalian, 116033, China
| | - Miao Sun
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, 675 Hoes Lane West, Piscataway, NJ, 08854, USA.
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29
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Chu YY, Ko CY, Wang WJ, Wang SM, Gean PW, Kuo YM, Wang JM. Astrocytic CCAAT/Enhancer Binding Protein δ Regulates Neuronal Viability and Spatial Learning Ability via miR-135a. Mol Neurobiol 2015. [PMID: 26208701 PMCID: PMC4937099 DOI: 10.1007/s12035-015-9359-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The progression of Alzheimer’s disease (AD) has been associated with astrocytes-induced neuroinflammation. However, the detailed mechanism of astrocytes associated with learning impairments and neuronal loss in AD is poorly defined. Here, we provide novel evidences that astrocytic miR-135a is critical for neuronal viability and spatial learning ability in vivo. The AppTg/Cebpd−/− mice showed a spatial learning improvement compared with the APPswe/PS1/E9 bigenic (AppTg) mice. miR-135a was found to be a CCAAT/enhancer binding protein δ (CEBPD) responsive miRNA and can repress the transcription of thrombospondin 1 (THBS1) / Thbs1 (mouse) via its 3′-untranslated region (3′UTR). We used different experimental approaches to attenuate the expression of CEBPD/Cebpd (mouse) or miR-135a in astrocytes and found the following results: increase in THBS1/Thbs1 expression, decrease in neuronal apoptosis, and increase in growth of neurites. Importantly, injection of miR-135a antagonist (AM135a) into the brain of AppTg mice was found to prevent neuronal apoptosis and improved the spatial learning ability. Together, our findings demonstrate a critical function for the astrocytic CEBPD, and point to miR-135a antagonist as an attractive therapeutic target for the treatment of Alzheimer’s disease.
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Affiliation(s)
- Yu-Yi Chu
- Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, 701, Taiwan
| | - Chiung-Yuan Ko
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, 110, Taiwan.,Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, 110, Taiwan
| | - Wei-Jan Wang
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, 701, Taiwan
| | - Shao-Ming Wang
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, 701, Taiwan
| | - Po-Wu Gean
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, 701, Taiwan.,Department of Pharmacology, National Cheng Kung University, Tainan, 701, Taiwan
| | - Yu-Min Kuo
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, 701, Taiwan.,Department of Cell Biology and Anatomy, National Cheng Kung University, Tainan, 701, Taiwan
| | - Ju-Ming Wang
- Institute of Bioinformatics and Biosignal Transduction, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, 701, Taiwan. .,Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, 701, Taiwan. .,Department of Cell Biology and Anatomy, National Cheng Kung University, Tainan, 701, Taiwan. .,Infectious Disease and Signaling Research Center, National Cheng Kung University, Tainan, 701, Taiwan. .,Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, 110, Taiwan.
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30
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Cochran JN, Hall AM, Roberson ED. The dendritic hypothesis for Alzheimer's disease pathophysiology. Brain Res Bull 2014; 103:18-28. [PMID: 24333192 PMCID: PMC3989444 DOI: 10.1016/j.brainresbull.2013.12.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 11/28/2013] [Accepted: 12/02/2013] [Indexed: 01/02/2023]
Abstract
Converging evidence indicates that processes occurring in and around neuronal dendrites are central to the pathogenesis of Alzheimer's disease. These data support the concept of a "dendritic hypothesis" of AD, closely related to the existing synaptic hypothesis. Here we detail dendritic neuropathology in the disease and examine how Aβ, tau, and AD genetic risk factors affect dendritic structure and function. Finally, we consider potential mechanisms by which these key drivers could affect dendritic integrity and disease progression. These dendritic mechanisms serve as a framework for therapeutic target identification and for efforts to develop disease-modifying therapeutics for Alzheimer's disease.
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Affiliation(s)
- J Nicholas Cochran
- Center for Neurodegeneration and Experimental Therapeutics, Departments of Neurology and Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Alicia M Hall
- Center for Neurodegeneration and Experimental Therapeutics, Departments of Neurology and Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Erik D Roberson
- Center for Neurodegeneration and Experimental Therapeutics, Departments of Neurology and Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States.
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31
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Serrano-Pozo A, Frosch MP, Masliah E, Hyman BT. Neuropathological alterations in Alzheimer disease. Cold Spring Harb Perspect Med 2013; 1:a006189. [PMID: 22229116 DOI: 10.1101/cshperspect.a006189] [Citation(s) in RCA: 2024] [Impact Index Per Article: 184.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The neuropathological hallmarks of Alzheimer disease (AD) include "positive" lesions such as amyloid plaques and cerebral amyloid angiopathy, neurofibrillary tangles, and glial responses, and "negative" lesions such as neuronal and synaptic loss. Despite their inherently cross-sectional nature, postmortem studies have enabled the staging of the progression of both amyloid and tangle pathologies, and, consequently, the development of diagnostic criteria that are now used worldwide. In addition, clinicopathological correlation studies have been crucial to generate hypotheses about the pathophysiology of the disease, by establishing that there is a continuum between "normal" aging and AD dementia, and that the amyloid plaque build-up occurs primarily before the onset of cognitive deficits, while neurofibrillary tangles, neuron loss, and particularly synaptic loss, parallel the progression of cognitive decline. Importantly, these cross-sectional neuropathological data have been largely validated by longitudinal in vivo studies using modern imaging biomarkers such as amyloid PET and volumetric MRI.
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Affiliation(s)
- Alberto Serrano-Pozo
- Alzheimer Research Unit of the MassGeneral Institute for Neurodegenerative Disease, Department of Neurology of the Massachusetts General Hospital, and Harvard Medical School, Charlestown, Massachusetts, USA, 02129-4404
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32
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Torres M, Jimenez S, Sanchez-Varo R, Navarro V, Trujillo-Estrada L, Sanchez-Mejias E, Carmona I, Davila JC, Vizuete M, Gutierrez A, Vitorica J. Defective lysosomal proteolysis and axonal transport are early pathogenic events that worsen with age leading to increased APP metabolism and synaptic Abeta in transgenic APP/PS1 hippocampus. Mol Neurodegener 2012; 7:59. [PMID: 23173743 PMCID: PMC3575255 DOI: 10.1186/1750-1326-7-59] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 11/04/2012] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Axonal pathology might constitute one of the earliest manifestations of Alzheimer disease. Axonal dystrophies were observed in Alzheimer's patients and transgenic models at early ages. These axonal dystrophies could reflect the disruption of axonal transport and the accumulation of multiple vesicles at local points. It has been also proposed that dystrophies might interfere with normal intracellular proteolysis. In this work, we have investigated the progression of the hippocampal pathology and the possible implication in Abeta production in young (6 months) and aged (18 months) PS1(M146L)/APP(751sl) transgenic mice. RESULTS Our data demonstrated the existence of a progressive, age-dependent, formation of axonal dystrophies, mainly located in contact with congophilic Abeta deposition, which exhibited tau and neurofilament hyperphosphorylation. This progressive pathology was paralleled with decreased expression of the motor proteins kinesin and dynein. Furthermore, we also observed an early decrease in the activity of cathepsins B and D, progressing to a deep inhibition of these lysosomal proteases at late ages. This lysosomal impairment could be responsible for the accumulation of LC3-II and ubiquitinated proteins within axonal dystrophies. We have also investigated the repercussion of these deficiencies on the APP metabolism. Our data demonstrated the existence of an increase in the amyloidogenic pathway, which was reflected by the accumulation of hAPPfl, C99 fragment, intracellular Abeta in parallel with an increase in BACE and gamma-secretase activities. In vitro experiments, using APPswe transfected N2a cells, demonstrated that any imbalance on the proteolytic systems reproduced the in vivo alterations in APP metabolism. Finally, our data also demonstrated that Abeta peptides were preferentially accumulated in isolated synaptosomes. CONCLUSION A progressive age-dependent cytoskeletal pathology along with a reduction of lysosomal and, in minor extent, proteasomal activity could be directly implicated in the progressive accumulation of APP derived fragments (and Abeta peptides) in parallel with the increase of BACE-1 and gamma-secretase activities. This retard in the APP metabolism seemed to be directly implicated in the synaptic Abeta accumulation and, in consequence, in the pathology progression between synaptically connected regions.
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Affiliation(s)
- Manuel Torres
- Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocio, Consejo Superior de Investigaciones Cientificas Universidad de Sevilla, c/ Manuel Siurot s/n, 41013, Sevilla, Spain
- Department Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Sevilla, 41012, Spain
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Sebastian Jimenez
- Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocio, Consejo Superior de Investigaciones Cientificas Universidad de Sevilla, c/ Manuel Siurot s/n, 41013, Sevilla, Spain
- Department Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Sevilla, 41012, Spain
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Raquel Sanchez-Varo
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- Department Biologia Celular, Genetica y Fisiologia, Facultad de Ciencias, Universidad de Malaga, Malaga, 29071, Spain
| | - Victoria Navarro
- Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocio, Consejo Superior de Investigaciones Cientificas Universidad de Sevilla, c/ Manuel Siurot s/n, 41013, Sevilla, Spain
- Department Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Sevilla, 41012, Spain
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Laura Trujillo-Estrada
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- Department Biologia Celular, Genetica y Fisiologia, Facultad de Ciencias, Universidad de Malaga, Malaga, 29071, Spain
| | - Elisabeth Sanchez-Mejias
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- Department Biologia Celular, Genetica y Fisiologia, Facultad de Ciencias, Universidad de Malaga, Malaga, 29071, Spain
| | - Irene Carmona
- Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocio, Consejo Superior de Investigaciones Cientificas Universidad de Sevilla, c/ Manuel Siurot s/n, 41013, Sevilla, Spain
- Department Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Sevilla, 41012, Spain
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Jose Carlos Davila
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- Department Biologia Celular, Genetica y Fisiologia, Facultad de Ciencias, Universidad de Malaga, Malaga, 29071, Spain
| | - Marisa Vizuete
- Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocio, Consejo Superior de Investigaciones Cientificas Universidad de Sevilla, c/ Manuel Siurot s/n, 41013, Sevilla, Spain
- Department Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Sevilla, 41012, Spain
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Antonia Gutierrez
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
- Department Biologia Celular, Genetica y Fisiologia, Facultad de Ciencias, Universidad de Malaga, Malaga, 29071, Spain
| | - Javier Vitorica
- Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocio, Consejo Superior de Investigaciones Cientificas Universidad de Sevilla, c/ Manuel Siurot s/n, 41013, Sevilla, Spain
- Department Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad de Sevilla, Sevilla, 41012, Spain
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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Sanchez-Varo R, Trujillo-Estrada L, Sanchez-Mejias E, Torres M, Baglietto-Vargas D, Moreno-Gonzalez I, De Castro V, Jimenez S, Ruano D, Vizuete M, Davila JC, Garcia-Verdugo JM, Jimenez AJ, Vitorica J, Gutierrez A. Abnormal accumulation of autophagic vesicles correlates with axonal and synaptic pathology in young Alzheimer's mice hippocampus. Acta Neuropathol 2012; 123:53-70. [PMID: 22020633 PMCID: PMC3249205 DOI: 10.1007/s00401-011-0896-x] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 09/27/2011] [Accepted: 10/13/2011] [Indexed: 12/25/2022]
Abstract
Dystrophic neurites associated with amyloid plaques precede neuronal death and manifest early in Alzheimer's disease (AD). In this work we have characterized the plaque-associated neuritic pathology in the hippocampus of young (4- to 6-month-old) PS1(M146L)/APP(751SL) mice model, as the initial degenerative process underlying functional disturbance prior to neuronal loss. Neuritic plaques accounted for almost all fibrillar deposits and an axonal origin of the dystrophies was demonstrated. The early induction of autophagy pathology was evidenced by increased protein levels of the autophagosome marker LC3 that was localized in the axonal dystrophies, and by electron microscopic identification of numerous autophagic vesicles filling and causing the axonal swellings. Early neuritic cytoskeletal defects determined by the presence of phosphorylated tau (AT8-positive) and actin-cofilin rods along with decreased levels of kinesin-1 and dynein motor proteins could be responsible for this extensive vesicle accumulation within dystrophic neurites. Although microsomal Aβ oligomers were identified, the presence of A11-immunopositive Aβ plaques also suggested a direct role of plaque-associated Aβ oligomers in defective axonal transport and disease progression. Most importantly, presynaptic terminals morphologically disrupted by abnormal autophagic vesicle buildup were identified ultrastructurally and further supported by synaptosome isolation. Finally, these early abnormalities in axonal and presynaptic structures might represent the morphological substrate of hippocampal dysfunction preceding synaptic and neuronal loss and could significantly contribute to AD pathology in the preclinical stages.
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34
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Yan J, Sun XB, Wang HQ, Zhao H, Zhao XY, Xu YX, Guo JC, Zhu CQ. Chronic restraint stress alters the expression and distribution of phosphorylated tau and MAP2 in cortex and hippocampus of rat brain. Brain Res 2010; 1347:132-41. [PMID: 20513368 DOI: 10.1016/j.brainres.2010.05.074] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Revised: 05/18/2010] [Accepted: 05/24/2010] [Indexed: 12/30/2022]
Abstract
Microtubule-associated proteins (MAPs) play a critical role in maintaining normal cytoskeletal architecture and functions. In the present study, we aim to explore the effects of the emotional stressor, chronic restraint stress, on the expression levels and localization of tau and MAP2. We found that after chronic restraint stress, soluble hyperphosphorylated tau was greatly increased, whereas MAP2 was decreased. Moreover, immunohistochemistry analysis demonstrated that phosphorylated tau and MAP2 displayed the similar subcellular distribution pattern after chronic restraint stress. Robust hyperphosphorylated tau immunolabeling was observed both in cortex and hippocampus of stressed animals and mainly located to perikaryal/dendritic elements. After stress, the MAP2 was mainly distributed in the perikaryal compartments, discontinuous dendrites and neuropil. Moreover, the distribution pattern of MAP2 in hippocampus significantly changed. Immunofluorescence double labeling indicated that hyperphosphorylated tau increased in the regions where there displayed an decrease of MAP2. These results suggest that the involvement of repeated restraint stress may not only induce phosphorylation state of tau and distribution of phosphorylated tau, but also alter the content and neuronal distribution of MAP2. Tau and MAP2 are most important MAPs for neuronal cells, the subcellular distribution change of them might be link to functional change of neurons after emotional stress.
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Affiliation(s)
- Jie Yan
- State Key Laboratory of Medical Neurobiology and Department of Neurobiology, Shanghai Medical College, Fudan University, 138 Yixueyuan Road, Shanghai 200032, PR China
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Teipel SJ, Pogarell O, Meindl T, Dietrich O, Sydykova D, Hunklinger U, Georgii B, Mulert C, Reiser MF, Möller HJ, Hampel H. Regional networks underlying interhemispheric connectivity: an EEG and DTI study in healthy ageing and amnestic mild cognitive impairment. Hum Brain Mapp 2009; 30:2098-119. [PMID: 18781594 DOI: 10.1002/hbm.20652] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interhemispheric coherence derived from electroencephalogram (EEG) recordings is a measure of functional interhemispheric connectivity. Diffusion tensor imaging (DTI) determines the integrity of subcortical fiber tracts. We studied the pattern of subcortical fiber tracts underlying interhemispheric coherence and its alteration in 16 subjects with amnestic mild cognitive impairment (MCI), an at risk syndrome for Alzheimer's disease, and 20 cognitively healthy elderly control subjects using resting state EEG and high resolution DTI at 3 T. We used a multivariate network approach based on principal component analysis to determine effects of coherence on the regional pattern of diffusivity. Temporo-parietal coherence in the alpha band was significantly correlated with diffusivity in predominantly posterior white matter tracts including posterior corpus callosum, parietal, temporal and occipital lobe white matter, thalamus, midbrain, pons, and cerebellum, both in MCI subjects and controls (P < 0.05). In MCI subjects, frontal coherence in the alpha band was significantly correlated with a predominately frontal pattern of diffusivity including fiber tracts of the anterior corpus callosum, frontal lobe white matter, thalamus, pons, and cerebellum (P < 0.05). The study provides a methodology to access specific networks of subcortical fiber tracts subserving the maintenance of interhemispheric resting state coherence in the human brain.
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Affiliation(s)
- Stefan J Teipel
- Department of Psychiatry, University of Rostock, Rostock, Germany.
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Shah SB, Nolan R, Davis E, Stokin GB, Niesman I, Canto I, Glabe C, Goldstein LSB. Examination of potential mechanisms of amyloid-induced defects in neuronal transport. Neurobiol Dis 2009; 36:11-25. [PMID: 19497367 DOI: 10.1016/j.nbd.2009.05.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Revised: 05/03/2009] [Accepted: 05/25/2009] [Indexed: 01/31/2023] Open
Abstract
Microtubule-based neuronal transport pathways are impaired during the progression of Alzheimer's disease and other neurodegenerative conditions. However, mechanisms leading to defects in transport remain to be determined. We quantified morphological changes in neuronal cells following treatment with fibrils and unaggregated peptides of beta-amyloid (Abeta). Abeta fibrils induce axonal and dendritic swellings indicative of impaired transport. In contrast, Abeta peptides induce a necrotic phenotype in both neurons and non-neuronal cells. We tested several popular hypotheses by which aggregated Abeta could disrupt transport. Using fluorescent polystyrene beads, we developed experimental models of physical blockage and localized release of reactive oxygen species (ROS) that reliably induce swellings. Like the beads, Abeta fibrils localize in close proximity to swellings; however, fibril internalization is not required for disrupting transport. ROS and membrane permeability are also unlikely to be responsible for fibril-mediated toxicity. Collectively, our results indicate that multiple initiating factors converge upon pathways of defective transport.
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Affiliation(s)
- Sameer B Shah
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
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Ding B, Chen KM, Ling HW, Zhang H, Chai WM, Li X, Wang T. Diffusion tensor imaging correlates with proton magnetic resonance spectroscopy in posterior cingulate region of patients with Alzheimer's disease. Dement Geriatr Cogn Disord 2008; 25:218-25. [PMID: 18219201 DOI: 10.1159/000113948] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/09/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS To compare proton magnetic resonance spectroscopy ((1)H-MRS) and diffusion tensor imaging (DTI) findings in the posterior cingulate regions in patients with Alzheimer's disease (AD). METHODS 17 patients with mild AD, 20 with moderate to severe AD and 20 cognitively normal aging subjects (CN) underwent single-voxel MRS and DTI examinations. A region of interest was positioned in the posterior cingulate regions. Ratios of N-acetylaspartate (NAA), myo-inositol (mI), and choline to creatine (Cr) were measured. Mean spectroscopy data and DTI values (fractional anisotropy, FA, and mean diffusivity, MD) were analyzed with nonparametric testing. RESULTS The group with mild AD showed a significantly lower FA value in the left posterior cingulum compared to CN. The group with moderate to severe AD revealed significantly decreased FA values and increased MD values in both the left and right cingulum compared to the group with mild AD. Partial correlation analysis revealed a positive correlation between mI/Cr and left-side FA values in the group with mild AD and a negative correlation between NAA/Cr and right-side MD values in the group with moderate to severe AD. CONCLUSION There are different regional and temporal patterns in AD, resulting from gliosis or axonal loss. Combining MRS with DTI could provide valuable information to better understand the AD process.
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Affiliation(s)
- Bei Ding
- Department of Radiology, Ruijin Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
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Teipel SJ, Meindl T, Grinberg L, Heinsen H, Hampel H. Novel MRI techniques in the assessment of dementia. Eur J Nucl Med Mol Imaging 2008; 35 Suppl 1:S58-69. [PMID: 18205002 DOI: 10.1007/s00259-007-0703-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
INTRODUCTION Positive markers of Alzheimer's disease (AD) have been established in MRI that may allow early detection of AD in at-risk groups. In the near future, these markers will be of high relevance for the selection of at-risk subjects in secondary preventive trials. METHODS We describe the methodology and diagnostic value of manual volumetry of the hippocampus and entorhinal cortex, automated voxel-based morphometry, cortical thickness measurement, basal forebrain volumetry and deformation-based morphometry, implementing multivariate statistics and machine learning algorithms to improve group separation and prediction of AD in at-risk groups. We also describe the methodological basis and results obtained in AD using the recently developed technique of diffusion tensor-based morphometry (DTI). This technique gives access to the integrity of subcortical fibre systems in the human brain. RESULTS The best established structural biomarker of AD to date is hippocampus volume that already has been implemented as secondary endpoint in clinical trials on disease modification in AD. Automated approaches will gain an increasing role as endpoints of clinical trials in the near future given the interest in these techniques expressed by the regulatory authorities. DTI is still a developing field where analysis techniques are presently being devised to make optimal use of the multivariate data. Data on changes of fibre tract in preclinical AD are still limited, but the first results are promising in respect to a further enhancement of diagnostic accuracy by combining MRI and DTI. CONCLUSION Besides their diagnostic use, MRI and DTI will broaden our understanding of the pathophysiology of AD and the structural and functional basis of normal cognition.
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Affiliation(s)
- Stefan J Teipel
- Dementia and Neuroimaging Section, Department of Psychiatry, Alzheimer Memorial Center, Ludwig-Maximilian University, Nussbaumstrasse 7, Munich, Germany.
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Insulin dysfunction induces in vivo tau hyperphosphorylation through distinct mechanisms. J Neurosci 2008; 27:13635-48. [PMID: 18077675 DOI: 10.1523/jneurosci.3949-07.2007] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Hyperphosphorylated tau is the major component of paired helical filaments in neurofibrillary tangles found in Alzheimer's disease (AD) brains, and tau hyperphosphorylation is thought to be a critical event in the pathogenesis of the disease. The large majority of AD cases is late onset and sporadic in origin, with aging as the most important risk factor. Insulin resistance, impaired glucose tolerance, and diabetes mellitus (DM) are other common syndromes in the elderly also strongly age dependent, and there is evidence supporting a link between insulin dysfunction and AD. To investigate the possibility that insulin dysfunction might promote tau pathology, we induced insulin deficiency and caused DM in mice with streptozotocin (STZ). A mild hyperphosphorylation of tau could be detected 10, 20, and 30 d after STZ injection, and a massive hyperphosphorylation of tau was observed after 40 d. The robust hyperphosphorylation of tau was localized in the axons and neuropil, and prevented tau binding to microtubules. Neither mild nor massive tau phosphorylation induced tau aggregation. Body temperature of the STZ-treated mice did not differ from control animals during 30 d, but dropped significantly thereafter. No change in beta-amyloid (Abeta) precursor protein (APP), APP C-terminal fragments, or Abeta levels were observed in STZ-treated mice; however, cellular protein phosphatase 2A activity was significantly decreased. Together, these data indicate that insulin dysfunction induced abnormal tau hyperphosphorylation through two distinct mechanisms: one was consequent to hypothermia; the other was temperature-independent, inherent to insulin depletion, and probably caused by inhibition of phosphatase activity.
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Teipel SJ, Stahl R, Dietrich O, Schoenberg SO, Perneczky R, Bokde ALW, Reiser MF, Möller HJ, Hampel H. Multivariate network analysis of fiber tract integrity in Alzheimer's disease. Neuroimage 2006; 34:985-95. [PMID: 17166745 DOI: 10.1016/j.neuroimage.2006.07.047] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Revised: 04/24/2006] [Accepted: 07/11/2006] [Indexed: 01/09/2023] Open
Abstract
Axonal and dendritic integrity is affected early in Alzheimer's disease (AD). Studies using region of interest or voxel-based analysis of diffusion tensor imaging data found significant decline of fractional anisotropy, a marker of fiber tract integrity, in selected white matter areas. We applied a multivariate network analysis based on principal component analysis to fractional anisotropy maps derived from diffusion-weighted scans from 15 AD patients, and 14 elderly healthy controls. Fractional anisotropy maps were obtained from an EPI diffusion sequence using parallel imaging to reduce distortion artifacts. We used high-dimensional image warping to control for partial volume effects due to white matter atrophy in AD. We found a significant regional pattern of fiber changes (p < 0.01) indicating that the integrity of intracortical projecting fiber tracts (including corpus callosum, cingulum and fornix, and frontal, temporal and occipital lobe white matter areas) was reduced, whereas extracortical projecting fiber tracts, including the pyramidal and extrapyramidal systems and somatosensory projections, were relatively preserved in AD. Effects of a univariate analysis were almost entirely contained within the multivariate effect. Our findings illustrate the use of a multivariate approach to fractional anisotropy data that takes advantage of the highly organized structure of anisotropy maps, and is independent of multiple comparison correction and partial volume effects. In agreement with post-mortem evidence, our study demonstrates dissociation between intracortical and extracortical projecting fiber systems in AD in the living human brain.
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Affiliation(s)
- Stefan J Teipel
- Alzheimer Memorial Center, Dementia and Neuroimaging Section, Department of Psychiatry, Ludwig-Maximilian University, Nussbaumstr.7, 80336 Munich, Germany.
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41
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Feng Q, Cheng B, Yang R, Sun FY, Zhu CQ. Dynamic changes of phosphorylated tau in mouse hippocampus after cold water stress. Neurosci Lett 2005; 388:13-6. [PMID: 16005567 DOI: 10.1016/j.neulet.2005.06.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Revised: 06/08/2005] [Accepted: 06/08/2005] [Indexed: 11/17/2022]
Abstract
The abnormal hyperphosphorylation of tau protein in brain is attributed to a number of neurodegenerative diseases such as Alzheimer disease. It has been reported that cold water stress (CWS) could cause rapid reversible tau phosphorylation in brain. To explore the possible long-tem effects of CWS on tau phosphorylation, we employed the immunoblot and immunohistochemical methods to analyze the phosphorylation of tau in the hippocampus of mice subjected to CWS. Results showed that CWS stimulation caused not only an early phase reversible tau phosphorylation, but also a later phase tau phosphorylation after 6h. The distribution pattern of phosphorylated tau (P-tau) in the later phase was different to that of early phase. At 1h after CWS, defined as early phase, P-tau was strikingly located in the mossy fibers and nerve terminals at the molecular layer of dentate gray (DG), whereas at 12h, defined as later phase, P-tau was dominantly located in the somatodendritic compartments of neurons in DG and CA3/CA1 regions, but obviously decreased in the mossy fibers and nerve terminals of molecular layer. These findings demonstrate that CWS leads to prominent changes of tau phosphorylation and P-tau localization in the hippocampus in a time dependent manner.
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Affiliation(s)
- Qiong Feng
- National Laboratory of Medical Neurobiology, Shanghai Medical College, Fudan University, 138 Yi-Xue-Yuan Road, Shanghai 200032, PR China
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42
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Spires TL, Meyer-Luehmann M, Stern EA, McLean PJ, Skoch J, Nguyen PT, Bacskai BJ, Hyman BT. Dendritic spine abnormalities in amyloid precursor protein transgenic mice demonstrated by gene transfer and intravital multiphoton microscopy. J Neurosci 2005; 25:7278-87. [PMID: 16079410 PMCID: PMC1820616 DOI: 10.1523/jneurosci.1879-05.2005] [Citation(s) in RCA: 412] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 06/13/2005] [Accepted: 07/01/2005] [Indexed: 12/16/2022] Open
Abstract
Accumulation of amyloid-beta (Abeta) into senile plaques in Alzheimer's disease (AD) is a hallmark neuropathological feature of the disorder, which likely contributes to alterations in neuronal structure and function. Recent work has revealed changes in neurite architecture associated with plaques and functional changes in cortical signaling in amyloid precursor protein (APP) expressing mouse models of AD. Here we developed a method using gene transfer techniques to introduce green fluorescent protein (GFP) into neurons, allowing the investigation of neuronal processes in the vicinity of plaques. Multiphoton imaging of GFP-labeled neurons in living Tg2576 APP mice revealed disrupted neurite trajectories and reductions in dendritic spine density compared with age-matched control mice. A profound deficit in spine density (approximately 50%) extends approximately 20 mum from plaque edges. Importantly, a robust decrement (approximately 25%) also occurs on dendrites not associated with plaques, suggesting widespread loss of postsynaptic apparatus. Plaques and dendrites remained stable over the course of weeks of imaging. Postmortem analysis of axonal immunostaining and colocalization of synaptophysin and postsynaptic density 95 protein staining around plaques indicate a parallel loss of presynaptic and postsynaptic partners. These results show considerable changes in dendrites and dendritic spines in APP transgenic mice, demonstrating a dramatic synaptotoxic effect of dense-cored plaques. Decreased spine density will likely contribute to altered neural system function and behavioral impairments observed in Tg2576 mice.
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Affiliation(s)
- Tara L Spires
- Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA
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43
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Abstract
During the course of Alzheimer's disease (AD), neurons undergo extensive remodeling, contributing to the loss of function observed in the disease. Many brain regions in patients with AD show changes in axonal and dendritic fields, dystrophic neurites, synapse loss, and neuron loss. Accumulation of amyloid-beta protein, a pathological hallmark of the disease, contributes to many of these alterations of neuronal structure. Areas of the brain displaying a high degree of plasticity are particularly vulnerable to degeneration in Alzheimer's disease. This article describes neuronal changes that occur in AD, reviews evidence that amyloid-beta contributes to these changes, and finally discusses the recovery of amyloid-induced changes in the brains of transgenic mice, lending hope to the idea that therapeutic strategies which reduce amyloid-beta production will lead to functional recovery in patients with AD.
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Affiliation(s)
- Tara L Spires
- Department of Neurology, Alzheimer's Disease Research Laboratory, Massachusetts General Hospital, Charlestown, MA 02129, USA.
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Abstract
Neurofibrillary degeneration, associated with the formation of paired helical filaments (PHF), is one of the critical neuropathological hallmarks of Alzheimer's disease (AD). Although the microtubule-associated protein tau in a hyperphosphorylated form has been established as primary PHF constituent, the process of tau phosphorylation and its potential link to degeneration is not very well understood, mostly because of the lack of a physiological in vivo model of PHF-like tau phosphorylation. PHF formation in AD follows a hierarchical pattern of development throughout different cortical areas, which closely matches the pattern of neuronal plasticity in the adult brain. Those brain areas are most early and most severely affected which are involved in the regulation of memory, learning, perception, self-awareness, consciousness, and higher brain functions that require a life-long re-fitting of connectivity, a process based on a particularly high degree of plasticity. Failures of synaptic plasticity are, thus, assumed to represent early events in the course of AD that eventually lead to alteration of tau phosphorylation. Recently, we have used the hibernation cycle, a physiological model of adaptation associated with an extraordinary high degree of structural neuronal plasticity, to analyze the potential link between synaptic plasticity, synaptic detachment and the regulation of tau phosphorylation. During torpor, a natural state of hypothermia, synaptic contacts between mossy fibers and hippocampal pyramidal neurons undergo dramatic regressive changes that are fully reversible very rapidly during euthermy. This rapid, reversible, and repeated regression of synaptic and dendritic components on CA3 neurons is associated with a reversible PHF-like phosphorylation of tau at a similar time course. The repeated formation and degradation of PHF-tau might, thus, represent a physiological mechanism not necessarily associated with pathological effects. These findings implicate an essential link between neuronal plasticity and PHF-like phosphorylation of tau, potentially involved in neurofibrillary degeneration.
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Affiliation(s)
- Thomas Arendt
- Paul Flechsig Institute of Brain Research, Department of Neuroanatomy, Jahnallee 59, D-04109 Leipzig, Germany.
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Planel E, Miyasaka T, Launey T, Chui DH, Tanemura K, Sato S, Murayama O, Ishiguro K, Tatebayashi Y, Takashima A. Alterations in glucose metabolism induce hypothermia leading to tau hyperphosphorylation through differential inhibition of kinase and phosphatase activities: implications for Alzheimer's disease. J Neurosci 2004; 24:2401-11. [PMID: 15014115 PMCID: PMC6729502 DOI: 10.1523/jneurosci.5561-03.2004] [Citation(s) in RCA: 190] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alzheimer's disease (AD) brains contain neurofibrillary tangles (NFTs) composed of abnormally hyperphosphorylated tau protein. Regional reductions in cerebral glucose metabolism correlating to NFT densities have been reported in AD brains. Assuming that reduced glucose metabolism might cause abnormal tau hyperphosphorylation, we induced in vivo alterations of glucose metabolism in mice by starvation or intraperitoneal injections of either insulin or deoxyglucose. We found that the treatments led to abnormal tau hyperphosphorylation with patterns resembling those in early AD brains and also resulted in hypothermia. Surprisingly, tau hyperphosphorylation could be traced down to a differential effect of low temperatures on kinase and phosphatase activities. These data indicate that abnormal tau hyperphosphorylation is associated with altered glucose metabolism through hypothermia. Our results imply that serine-threonine protein phosphatase 2A plays a major role in regulating tau phosphorylation in the adult brain and provide in vivo evidence for its crucial role in abnormal tau hyperphosphorylation in AD.
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Affiliation(s)
- Emmanuel Planel
- Laboratory for Alzheimer's Disease, The Institute of Physical and Chemical Research, Wako-shi, Saitama 351-0198, Japan
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Abstract
Ramon y Cajal proclaimed in 1928 that "once development was ended, the founts of growth and regeneration of the axons and dendrites dried up irrevocably. In the adult centers the nerve paths are something fixed, ended and immutable. Everything must die, nothing may be regenerated. It is for the science of the future to change, if possible, this harsh decree." (Ramon y Cajal, 1928). In large part, despite the extensive knowledge gained since then, the latter directive has not yet been achieved by 'modern' science. Although we know now that Ramon y Cajal's observation on CNS plasticity is largely true (for lower brain and primary cortical structures), there are mechanisms for recovery from CNS injury. These mechanisms, however, may contribute to the vulnerability to neurodegenerative disease. They may also be exploited therapeutically to help alleviate the suffering from neurodegenerative conditions.
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Affiliation(s)
- Bruce Teter
- Department of Medicine, University of California Los Angeles, California and Veteran's Affairs-Greater Los Angeles Healthcare System, Sepulveda, California 91343, USA
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Abstract
In order to fully evaluate the effects of colchicine treatment on learning ability in rats, colchicine was administered, and both Morris water maze (MWM) and step-through type passive avoidance (PA) learning tests were conducted. In both learning tests, infusion of colchicine into the rat dentate gyrus, at two distinct bilateral rostrocaudal locations, potently impaired memory function in a dose-dependent manner (0.01-2.0 microg/site), whereas systemic injection of colchicine (50-300 microg/kg) did not. In the MWM test, memory impairment was observed even at doses where there was no evidence of any histological changes in the dentate granule cells. This suggests that functional deterioration, that is, learning impairment was induced by the dysfunction of microtubules and/or axons, was caused by colchicine. Moreover, ameliorated learning behavior was observed with chronic treatment of beta-estradiol 3-benzoate, which has been suggested to have an important role as an adjuvant treatment for younger Alzheimer's disease (AD), immediately after colchicine infusion (0.3 microg). These results indicate that the animal model accompanying the colchicine-induced functional defect showing early tau pathology, but not neuronal cell degeneration, may well mimic comparatively early stage of AD.
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Affiliation(s)
- Takahiro Nakayama
- BF Research Institute, Inc., c/o National Cardiovascular Center, 7-1, 5-Chome, Fujishiro-dai, Suita, Osaka 565-0873, Japan.
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Koudinov AR, Koudinova NV. Essential role for cholesterol in synaptic plasticity and neuronal degeneration. FASEB J 2001; 15:1858-60. [PMID: 11481254 DOI: 10.1096/fj.00-0815fje] [Citation(s) in RCA: 193] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- A R Koudinov
- Institute of Biomedical Chemistry and. National Mental Health Research Center, Russian Academy of Medical Sciences, 38-27, Moscow, 121359 Russia.
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Arendt T. Disturbance of neuronal plasticity is a critical pathogenetic event in Alzheimer's disease. Int J Dev Neurosci 2001; 19:231-45. [PMID: 11337192 DOI: 10.1016/s0736-5748(01)00007-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Brain areas affected by AD pathology are primarily those structures that are invovled in the regulation of "higher brain functions". The functions these areas subserve such as learning, memory, perception, self-awareness, and consciousness require a life-long re-fittng of synaptic contacts that allows for the acquistion of new epigenetic information, a process based on a particularly high degree of structural plasticity. Here, we outline a hypothesis that it is the "labile state fo differentiation" of a subset of neurons in the adult brain that allows for ongoing neuroplastic processes after development is completed but at the same time renders these neurons particularly vulnerable. Mechanisms of molecular and cellular control of neuronal differentiation and proliferation might, thus, not only play a role during development but critically involved in the pathogenesis of neurodegeneration.
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Affiliation(s)
- T Arendt
- Department of Neuranatomy, Paul Flechsig Institute of Brain Research, University of Leipzig, Jahnallee 59, D-04109, Leipzig, Germany.
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Arendt T. Alzheimer's disease as a disorder of mechanisms underlying structural brain self-organization. Neuroscience 2001; 102:723-65. [PMID: 11182240 DOI: 10.1016/s0306-4522(00)00516-9] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mental function has as its cerebral basis a specific dynamic structure. In particular, cortical and limbic areas involved in "higher brain functions" such as learning, memory, perception, self-awareness and consciousness continuously need to be self-adjusted even after development is completed. By this lifelong self-optimization process, the cognitive, behavioural and emotional reactivity of an individual is stepwise remodelled to meet the environmental demands. While the presence of rigid synaptic connections ensures the stability of the principal characteristics of function, the variable configuration of the flexible synaptic connections determines the unique, non-repeatable character of an experienced mental act. With the increasing need during evolution to organize brain structures of increasing complexity, this process of selective dynamic stabilization and destabilization of synaptic connections becomes more and more important. These mechanisms of structural stabilization and labilization underlying a lifelong synaptic remodelling according to experience, are accompanied, however, by increasing inherent possibilities of failure and may, thus, not only allow for the evolutionary acquisition of "higher brain function" but at the same time provide the basis for a variety of neuropsychiatric disorders. It is the objective of the present paper to outline the hypothesis that it might be the disturbance of structural brain self-organization which, based on both genetic and epigenetic information, constantly "creates" and "re-creates" the brain throughout life, that is the defect that underlies Alzheimer's disease (AD). This hypothesis is, in particular, based on the following lines of evidence. (1) AD is a synaptic disorder. (2) AD is associated with aberrant sprouting at both the presynaptic (axonal) and postsynaptic (dendritic) site. (3) The spatial and temporal distribution of AD pathology follows the pattern of structural neuroplasticity in adulthood, which is a developmental pattern. (4) AD pathology preferentially involves molecules critical for the regulation of modifications of synaptic connections, i.e. "morphoregulatory" molecules that are developmentally controlled, such as growth-inducing and growth-associated molecules, synaptic molecules, adhesion molecules, molecules involved in membrane turnover, cytoskeletal proteins, etc. (5) Life events that place an additional burden on the plastic capacity of the brain or that require a particularly high plastic capacity of the brain might trigger the onset of the disease or might stimulate a more rapid progression of the disease. In other words, they might increase the risk for AD in the sense that they determine when, not whether, one gets AD. (6) AD is associated with a reactivation of developmental programmes that are incompatible with a differentiated cellular background and, therefore, lead to neuronal death. From this hypothesis, it can be predicted that a therapeutic intervention into these pathogenetic mechanisms is a particular challenge as it potentially interferes with those mechanisms that at the same time provide the basis for "higher brain function".
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Affiliation(s)
- T Arendt
- Paul Flechsig Institute of Brain Research, Department of Neuroanatomy, University of Leipzig, Jahnallee 59, D-04109, Leipzig, Germany.
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