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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: 15] [Impact Index Per Article: 5.0] [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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Zhang XQ, Xu L, Yang SY, Hu LB, Dong FY, Sun BG, Shen HW. Reduced Synaptic Transmission and Intrinsic Excitability of a Subtype of Pyramidal Neurons in the Medial Prefrontal Cortex in a Mouse Model of Alzheimer's Disease. J Alzheimers Dis 2021; 84:129-140. [PMID: 34487044 DOI: 10.3233/jad-210585] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Abnormal morphology and function of neurons in the prefrontal cortex (PFC) are associated with cognitive deficits in rodent models of Alzheimer's disease (AD), particularly in cortical layer-5 pyramidal neurons that integrate inputs from different sources and project outputs to cortical or subcortical structures. Pyramidal neurons in layer-5 of the PFC can be classified as two subtypes depending on the inducibility of prominent hyperpolarization-activated cation currents (h-current). However, the differences in the neurophysiological alterations between these two subtypes in rodent models of AD remain poorly understood. OBJECTIVE To investigate the neurophysiological alterations between two subtypes of pyramidal neurons in hAPP-J20 mice, a transgenic model for early onset AD. METHODS The synaptic transmission and intrinsic excitability of pyramidal neurons were investigated using whole-cell patch recordings. The morphological complexity of pyramidal neurons was detected by biocytin labelling and subsequent Sholl analysis. RESULTS We found reduced synaptic transmission and intrinsic excitability of the prominent h-current (PH) cells but not the non-PH cells in hAPP-J20 mice. Furthermore, the function of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels which mediated h-current was disrupted in the PH cells of hAPP-J20 mice. Sholl analysis revealed that PH cells had less dendritic intersections in hAPP-J20 mice comparing to control mice, implying that a lower morphological complexity might contribute to the reduced neuronal activity. CONCLUSION These results suggest that the PH cells in the medial PFC may be more vulnerable to degeneration in hAPP-J20 mice and play a sustainable role in frontal dysfunction in AD.
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Affiliation(s)
- Xiao-Qin Zhang
- Department of Pharmacology, School of Medicine, Zhejiang Key Laboratory of Pathophysiology, Ningbo University, Ningbo, Zhejiang, China.,Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
| | - Le Xu
- Department of Pharmacology, School of Medicine, Zhejiang Key Laboratory of Pathophysiology, Ningbo University, Ningbo, Zhejiang, China
| | - Si-Yu Yang
- Department of Pharmacology, School of Medicine, Zhejiang Key Laboratory of Pathophysiology, Ningbo University, Ningbo, Zhejiang, China
| | - Lin-Bo Hu
- Department of Pharmacology, School of Medicine, Zhejiang Key Laboratory of Pathophysiology, Ningbo University, Ningbo, Zhejiang, China
| | - Fei-Yuan Dong
- Department of Pharmacology, School of Medicine, Zhejiang Key Laboratory of Pathophysiology, Ningbo University, Ningbo, Zhejiang, China
| | - Bing-Gui Sun
- Department of Neurobiology, NHC and CAMS Key Laboratory of Medical Neurobiology, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Hao-Wei Shen
- Department of Pharmacology, School of Medicine, Zhejiang Key Laboratory of Pathophysiology, Ningbo University, Ningbo, Zhejiang, China.,Key Laboratory of Addiction Research of Zhejiang Province, Ningbo Kangning Hospital, Ningbo, Zhejiang, China
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Borroni V, Barrantes FJ. Homomeric and Heteromeric α7 Nicotinic Acetylcholine Receptors in Health and Some Central Nervous System Diseases. MEMBRANES 2021; 11:membranes11090664. [PMID: 34564481 PMCID: PMC8465519 DOI: 10.3390/membranes11090664] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 11/22/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels involved in the modulation of essential brain functions such as memory, learning, and attention. Homomeric α7 nAChR, formed exclusively by five identical α7 subunits, is involved in rapid synaptic transmission, whereas the heteromeric oligomers composed of α7 in combination with β subunits display metabotropic properties and operate in slower time frames. At the cellular level, the activation of nAChRs allows the entry of Na+ and Ca2+; the two cations depolarize the membrane and trigger diverse cellular signals, depending on the type of nAChR pentamer and neurons involved, the location of the intervening cells, and the networks of which these neuronal cells form part. These features make the α7 nAChR a central player in neurotransmission, metabolically associated Ca2+-mediated signaling, and modulation of diverse fundamental processes operated by other neurotransmitters in the brain. Due to its ubiquitous distribution and the multiple functions it displays in the brain, the α7 nAChR is associated with a variety of neurological and neuropsychiatric disorders whose exact etiopathogenic mechanisms are still elusive.
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Affiliation(s)
- Virginia Borroni
- Instituto de Tecnología en Polímeros y Nanotecnología (ITPN-UBA-CONICET), Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires C1127AAR, Argentina;
| | - Francisco J. Barrantes
- Laboratory of Molecular Neurobiology, Institute for Biomedical Research, UCA–CONICET, Faculty of Medical Sciences, Catholic University of Argentina, Av. Alicia Moreau de Justo 1600, Buenos Aires C1107AAZ, Argentina
- Correspondence:
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The Amyloid-Tau-Neuroinflammation Axis in the Context of Cerebral Amyloid Angiopathy. Int J Mol Sci 2019; 20:ijms20246319. [PMID: 31847365 PMCID: PMC6941131 DOI: 10.3390/ijms20246319] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 12/10/2019] [Accepted: 12/12/2019] [Indexed: 12/15/2022] Open
Abstract
Cerebral amyloid angiopathy (CAA) is typified by the cerebrovascular deposition of amyloid. Currently, there is no clear understanding of the mechanisms underlying the contribution of CAA to neurodegeneration. Despite the fact that CAA is highly associated with the accumulation of Aβ, other types of amyloids have been shown to associate with the vasculature. Interestingly, in many cases, vascular amyloidosis has been associated with an active immune response and perivascular deposition of hyperphosphorylated tau. Despite the fact that in Alzheimer’s disease (AD) a major focus of research has been the understanding of the connection between parenchymal amyloid plaques, tau aggregates in the form of neurofibrillary tangles (NFTs), and immune activation, the contribution of tau and neuroinflammation to neurodegeneration associated with CAA remains understudied. In this review, we discussed the existing evidence regarding the amyloid diversity in CAA and its relation to tau pathology and immune response, as well as the possible contribution of molecular and cellular mechanisms, previously associated with parenchymal amyloid in AD and AD-related dementias, to the pathogenesis of CAA. The detailed understanding of the “amyloid-tau-neuroinflammation” axis in the context of CAA could open the opportunity to develop therapeutic interventions for dementias associated with CAA that are currently being proposed for AD and AD-related dementias.
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Density of small dendritic spines and microtubule-associated-protein-2 immunoreactivity in the primary auditory cortex of subjects with schizophrenia. Neuropsychopharmacology 2019; 44:1055-1061. [PMID: 30795003 PMCID: PMC6461932 DOI: 10.1038/s41386-019-0350-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/15/2019] [Accepted: 02/16/2019] [Indexed: 12/22/2022]
Abstract
Previously, we demonstrated that dendritic spine density (DSD) in deep layer 3 of the primary auditory cortex (A1) is lower, due to having fewer small spines, in subjects with schizophrenia (SZ) than non-psychiatric control (NPC) subjects. We also previously demonstrated that microtubule-associated-protein-2 immunoreactivity (MAP2-IR) in A1 deep layer 3 is lower, and positively correlated with DSD, in SZ subjects. Here, we first sought to confirm these findings in an independent cohort of 25 SZ-NPC subject pairs (cohort 1). We used immunohistochemistry and confocal microscopy to measure DSD and MAP2-IR in A1 deep layer 3. Consistent with previous studies, both DSD and MAP2-IR were lower in SZ subjects. We then tested the hypothesis that MAP2-IR mediates the effect of SZ on DSD in a cohort of 45 SZ-NPC subject pairs (combined cohort) that included all subjects from cohort 1 and two previously studied cohorts. Based on the distribution of MAP2-IR values in NPC subjects, we categorized each SZ subject as having either low MAP2-IR (SZ MAP2-IR(low)) or normal MAP2-IR (SZ MAP2-IR(normal)). Among SZ MAP-IR(low) subjects, mean DSD was significantly lower than in NPC subjects. However, mean DSD did not differ between SZ MAP2-IR(normal) and NPC subjects. Moreover, MAP2-IR statistically mediated small spine differences, with lower MAP2-IR values associated with fewer small spines. Our findings confirm that low density of small spines and low MAP2-IR are robust SZ phenotypes and suggest that MAP2-IR mediates the effect of SZ on DSD.
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Fibrinogen Induces Microglia-Mediated Spine Elimination and Cognitive Impairment in an Alzheimer's Disease Model. Neuron 2019; 101:1099-1108.e6. [PMID: 30737131 DOI: 10.1016/j.neuron.2019.01.014] [Citation(s) in RCA: 243] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 09/21/2018] [Accepted: 01/04/2019] [Indexed: 12/14/2022]
Abstract
Cerebrovascular alterations are a key feature of Alzheimer's disease (AD) pathogenesis. However, whether vascular damage contributes to synaptic dysfunction and how it synergizes with amyloid pathology to cause neuroinflammation and cognitive decline remain poorly understood. Here, we show that the blood protein fibrinogen induces spine elimination and promotes cognitive deficits mediated by CD11b-CD18 microglia activation. 3D molecular labeling in cleared mouse and human AD brains combined with repetitive in vivo two-photon imaging showed focal fibrinogen deposits associated with loss of dendritic spines independent of amyloid plaques. Fibrinogen-induced spine elimination was prevented by inhibiting reactive oxygen species (ROS) generation or genetic ablation of CD11b. Genetic elimination of the fibrinogen binding motif to CD11b reduced neuroinflammation, synaptic deficits, and cognitive decline in the 5XFAD mouse model of AD. Thus, fibrinogen-induced spine elimination and cognitive decline via CD11b link cerebrovascular damage with immune-mediated neurodegeneration and may have important implications in AD and related conditions.
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Medawar E, Benway TA, Liu W, Hanan TA, Haslehurst P, James OT, Yap K, Muessig L, Moroni F, Nahaboo Solim MA, Baidildinova G, Wang R, Richardson JC, Cacucci F, Salih DA, Cummings DM, Edwards FA. Effects of rising amyloidβ levels on hippocampal synaptic transmission, microglial response and cognition in APP Swe/PSEN1 M146V transgenic mice. EBioMedicine 2019; 39:422-435. [PMID: 30555043 PMCID: PMC6354711 DOI: 10.1016/j.ebiom.2018.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 12/03/2018] [Accepted: 12/05/2018] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Progression of Alzheimer's disease is thought initially to depend on rising amyloidβ and its synaptic interactions. Transgenic mice (TASTPM; APPSwe/PSEN1M146V) show altered synaptic transmission, compatible with increased physiological function of amyloidβ, before plaques are detected. Recently, the importance of microglia has become apparent in the human disease. Similarly, TASTPM show a close association of plaque load with upregulated microglial genes. METHODS CA1 synaptic transmission and plasticity were investigated using in vitro electrophysiology. Microglial relationship to plaques was examined with immunohistochemistry. Behaviour was assessed with a forced-alternation T-maze, open field, light/dark box and elevated plus maze. FINDINGS The most striking finding is the increase in microglial numbers in TASTPM, which, like synaptic changes, begins before plaques are detected. Further increases and a reactive phenotype occur later, concurrent with development of larger plaques. Long-term potentiation is initially enhanced at pre-plaque stages but decrements with the initial appearance of plaques. Finally, despite altered plasticity, TASTPM have little cognitive deficit, even with a heavy plaque load, although they show altered non-cognitive behaviours. INTERPRETATION The pre-plaque synaptic changes and microglial proliferation are presumably related to low, non-toxic amyloidβ levels in the general neuropil and not directly associated with plaques. However, as plaques grow, microglia proliferate further, clustering around plaques and becoming phagocytic. Like in humans, even when plaque load is heavy, without development of neurofibrillary tangles and neurodegeneration, these alterations do not result in cognitive deficits. Behaviours are seen that could be consistent with pre-diagnosis changes in the human condition. FUNDING GlaxoSmithKline; BBSRC; UCL; ARUK; MRC.
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Affiliation(s)
- Evelyn Medawar
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK..
| | - Tiffanie A Benway
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK..
| | - Wenfei Liu
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK..
| | - Taylor A Hanan
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Peter Haslehurst
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK..
| | - Owain T James
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Kenrick Yap
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Laurenz Muessig
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK..
| | - Fabia Moroni
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Muzammil A Nahaboo Solim
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.; Institute of Cellular Medicine, Newcastle University Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK..
| | - Gaukhar Baidildinova
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.; Department of Science and Innovations, Asfendiyarov Kazakh National Medical University, Zhamakayev Street, Almaty, A26P6B5, Kazakhstan
| | - Rui Wang
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK..
| | - Jill C Richardson
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK..
| | - Francesca Cacucci
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK..
| | - Dervis A Salih
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK..
| | - Damian M Cummings
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK..
| | - Frances A Edwards
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK..
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Heiss JK, Barrett J, Yu Z, Haas LT, Kostylev MA, Strittmatter SM. Early Activation of Experience-Independent Dendritic Spine Turnover in a Mouse Model of Alzheimer's Disease. Cereb Cortex 2018; 27:3660-3674. [PMID: 27365298 DOI: 10.1093/cercor/bhw188] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Synaptic loss is critical in Alzheimer's disease (AD), but the dynamics of synapse turnover are poorly defined. We imaged dendritic spines in transgenic APPswe/PSen1∆E9 (APP/PS1) cerebral cortex. Dendritic spine turnover is increased far from plaque in aged APP/PS1 mice, and in young APP/PS1 mice prior to plaque formation. Dysregulation occurs in the presence of soluble Aβ oligomer and requires cellular prion protein (PrPC). APP/PS1 mice lack responsiveness of spine turnover to sensory stimulation. Critically, enhanced spine turnover is coupled with the loss of persistent spines starting early and continuing with age. To evaluate mechanisms of experience-independent supranormal spine turnover, we analyzed the transcriptome of young APP/PS1 mouse brain when turnover is altered but synapse density and memory are normal, and plaque and inflammation are absent. Early PrPC-dependent expression changes occur in synaptic and lipid-metabolizing genes. Thus, pathologic synaptic dysregulation underlying AD begins at a young age prior to Aβ plaque.
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Affiliation(s)
- Jacqueline K Heiss
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA.,Department of Pharmacology, Yale University School of Medicine, New Haven CT 06520, USA
| | - Joshua Barrett
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Zizi Yu
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Laura T Haas
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Mikhail A Kostylev
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Stephen M Strittmatter
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06536, USA.,Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
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Parker EM, Sweet RA. Stereological Assessments of Neuronal Pathology in Auditory Cortex in Schizophrenia. Front Neuroanat 2018; 11:131. [PMID: 29375326 PMCID: PMC5767177 DOI: 10.3389/fnana.2017.00131] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 12/18/2017] [Indexed: 12/21/2022] Open
Abstract
It has long been known that auditory processing is disrupted in schizophrenia. More recently, postmortem studies have provided direct evidence that morphological alterations to neurons in auditory cortex are implicated in the pathophysiology of this illness, confirming previous predictions. Potential neural substrates for auditory impairment and gray matter loss in auditory cortex in schizophrenia have been identified, described, and are the focus of this review article. Pyramidal cell somal volume is reduced in auditory cortex, as are dendritic spine density and number in schizophrenia. Pyramidal cells are not lost in this region in schizophrenia, indicating that dendritic spine reductions reflect fewer spines per pyramidal cell, consistent with the reduced neuropil hypothesis of schizophrenia. Stereological methods have aided in the proper collection, reporting and interpretation of this data. Mechanistic studies exploring relationships between genetic risk for schizophrenia and altered dendrite morphology represent an important avenue for future research in order to further elucidate cellular pathology in auditory cortex in schizophrenia.
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Affiliation(s)
- Emily M Parker
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States
| | - Robert A Sweet
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Neurology, University of Pittsburgh, Pittsburgh, PA, United States.,VISN 4 Mental Illness Research, Education and Clinical Center (MIRECC), VA Pittsburgh Healthcare System, Pittsburgh, PA, United States
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Trim9 Deletion Alters the Morphogenesis of Developing and Adult-Born Hippocampal Neurons and Impairs Spatial Learning and Memory. J Neurosci 2017; 36:4940-58. [PMID: 27147649 DOI: 10.1523/jneurosci.3876-15.2016] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 03/07/2016] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED During hippocampal development, newly born neurons migrate to appropriate destinations, extend axons, and ramify dendritic arbors to establish functional circuitry. These developmental stages are recapitulated in the dentate gyrus of the adult hippocampus, where neurons are continuously generated and subsequently incorporate into existing, local circuitry. Here we demonstrate that the E3 ubiquitin ligase TRIM9 regulates these developmental stages in embryonic and adult-born mouse hippocampal neurons in vitro and in vivo Embryonic hippocampal and adult-born dentate granule neurons lacking Trim9 exhibit several morphological defects, including excessive dendritic arborization. Although gross anatomy of the hippocampus was not detectably altered by Trim9 deletion, a significant number of Trim9(-/-) adult-born dentate neurons localized inappropriately. These morphological and localization defects of hippocampal neurons in Trim9(-/-) mice were associated with extreme deficits in spatial learning and memory, suggesting that TRIM9-directed neuronal morphogenesis may be involved in hippocampal-dependent behaviors. SIGNIFICANCE STATEMENT Appropriate generation and incorporation of adult-born neurons in the dentate gyrus are critical for spatial learning and memory and other hippocampal functions. Here we identify the brain-enriched E3 ubiquitin ligase TRIM9 as a novel regulator of embryonic and adult hippocampal neuron shape acquisition and hippocampal-dependent behaviors. Genetic deletion of Trim9 elevated dendritic arborization of hippocampal neurons in vitro and in vivo Adult-born dentate granule cells lacking Trim9 similarly exhibited excessive dendritic arborization and mislocalization of cell bodies in vivo These cellular defects were associated with severe deficits in spatial learning and memory.
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11
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Zhao R, Hu W, Tsai J, Li W, Gan WB. Microglia limit the expansion of β-amyloid plaques in a mouse model of Alzheimer's disease. Mol Neurodegener 2017; 12:47. [PMID: 28606182 PMCID: PMC5468952 DOI: 10.1186/s13024-017-0188-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 06/02/2017] [Indexed: 11/25/2022] Open
Abstract
Background Microglia are known as resident immune cells in the brain. β-amyloid (Aβ) plaques in the brain of Alzheimer’s disease (AD) are surrounded by microglia, but whether and how microglia affect the formation and maintenance of plaques remains controversial. Methods We depleted microglia by injecting diphtheria toxin (DT) in CX3CR1CreER/+:R26DTR/+ (CX3CR1-iDTR) mice crossed with APPswe/PSEN1dE9 (APP/PS1) mice. Intravital time-lapse imaging was performed to examine changes in the number and size of Congo Red-labeled amyloid plaques over 1–2 weeks. We also examined spine density and shaft diameter of dendrites passing through plaques in a PSAPP mouse model of AD (PS1M146L line 6.2 × Tg2576) crossed with Thy1 YFP H-line mice. Results We found that DT administration to CX3CR1-iDTR mice efficiently ablated microglia within one week and that microglia repopulated in the second week after DT administration. Microglia depletion didn’t affect the number of amyloid plaques, but led to ~13% increase in the size of Aβ plaques within one week. Moreover, microglia repopulation was associated with the stabilization of plaque size during the second week. In addition, we found dendritic spine loss and shaft atrophy in the distal parts of dendrites passing through plaques. Conclusion Our results demonstrate the important role of microglia in limiting the growth of Aβ plaques and plaque-associated disruption of neuronal connection. Electronic supplementary material The online version of this article (doi:10.1186/s13024-017-0188-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ruohe Zhao
- Drug Discovery Center, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.,Skirball Institute, New York University School of Medicine, New York, NY, 10016, USA
| | - Wanling Hu
- Drug Discovery Center, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Julia Tsai
- Skirball Institute, New York University School of Medicine, New York, NY, 10016, USA
| | - Wei Li
- Drug Discovery Center, Peking University Shenzhen Graduate School, Shenzhen, 518055, China. .,Skirball Institute, New York University School of Medicine, New York, NY, 10016, USA.
| | - Wen-Biao Gan
- Drug Discovery Center, Peking University Shenzhen Graduate School, Shenzhen, 518055, China. .,Skirball Institute, New York University School of Medicine, New York, NY, 10016, USA.
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12
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Loss of precuneus dendritic spines immunopositive for spinophilin is related to cognitive impairment in early Alzheimer's disease. Neurobiol Aging 2017; 55:159-166. [PMID: 28259365 PMCID: PMC5440205 DOI: 10.1016/j.neurobiolaging.2017.01.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/27/2017] [Accepted: 01/27/2017] [Indexed: 01/25/2023]
Abstract
Precuneus (PreC) cortex is affected with amyloid plaques early in Alzheimer's disease (AD), and this pathology may be associated with alterations in PreC synapses and cognitive impairment. We quantified the spinophilin-immunoreactive (ir) dendritic spine density and the intensity of spinophilin immunofluorescence, the latter as a measure of relative protein levels of spinophilin, in PreC lamina III from 33 subjects with clinical diagnoses of no cognitive impairment (NCI), mild cognitive impairment (MCI), mild-moderate AD (mAD), or severe AD (sAD). Both measures of spinophilin were lower in mAD and sAD compared with NCI. The MCI group had higher protein levels of spinophilin compared with mAD and sAD, and higher spinophilin-ir dendritic spine density compared with sAD. Lower spinophilin-ir dendritic spine density and relative protein levels of spinophilin were associated with greater amyloid beta (Aβ) plaque burden, detected with a derivative of Pittsburgh compound-B (6-CN-PiB), and worse cognitive performance. Clinical onset of AD is marked by the loss of PreC spinophilin-ir dendritic spines that is related to Aβ pathology and may contribute to cognitive symptoms early in the disease.
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13
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Zhang C, Kuo CC, Moghadam SH, Monte L, Campbell SN, Rice KC, Sawchenko PE, Masliah E, Rissman RA. Corticotropin-releasing factor receptor-1 antagonism mitigates beta amyloid pathology and cognitive and synaptic deficits in a mouse model of Alzheimer's disease. Alzheimers Dement 2016; 12:527-37. [PMID: 26555315 PMCID: PMC4860182 DOI: 10.1016/j.jalz.2015.09.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 09/27/2015] [Accepted: 09/28/2015] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Stress and corticotropin-releasing factor (CRF) have been implicated as mechanistically involved in Alzheimer's disease (AD), but agents that impact CRF signaling have not been carefully tested for therapeutic efficacy or long-term safety in animal models. METHODS To test whether antagonism of the type-1 corticotropin-releasing factor receptor (CRFR1) could be used as a disease-modifying treatment for AD, we used a preclinical prevention paradigm and treated 30-day-old AD transgenic mice with the small-molecule, CRFR1-selective antagonist, R121919, for 5 months, and examined AD pathologic and behavioral end points. RESULTS R121919 significantly prevented the onset of cognitive impairment in female mice and reduced cellular and synaptic deficits and beta amyloid and C-terminal fragment-β levels in both genders. We observed no tolerability or toxicity issues in mice treated with R121919. DISCUSSION CRFR1 antagonism presents a viable disease-modifying therapy for AD, recommending its advancement to early-phase human safety trials.
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Affiliation(s)
- Cheng Zhang
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Ching-Chang Kuo
- NeuroInformatics Center, University of Oregon, Eugene, OR, USA
| | - Setareh H Moghadam
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Louise Monte
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Shannon N Campbell
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Kenner C Rice
- Chemical Biology Research Branch, National Institute on Drug Abuse and Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | | | - Eliezer Masliah
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA; Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Robert A Rissman
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA.
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14
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Regulation of the Postsynaptic Compartment of Excitatory Synapses by the Actin Cytoskeleton in Health and Its Disruption in Disease. Neural Plast 2016; 2016:2371970. [PMID: 27127658 PMCID: PMC4835652 DOI: 10.1155/2016/2371970] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 03/09/2016] [Indexed: 02/07/2023] Open
Abstract
Disruption of synaptic function at excitatory synapses is one of the earliest pathological changes seen in wide range of neurological diseases. The proper control of the segregation of neurotransmitter receptors at these synapses is directly correlated with the intact regulation of the postsynaptic cytoskeleton. In this review, we are discussing key factors that regulate the structure and dynamics of the actin cytoskeleton, the major cytoskeletal building block that supports the postsynaptic compartment. Special attention is given to the complex interplay of actin-associated proteins that are found in the synaptic specialization. We then discuss our current understanding of how disruption of these cytoskeletal elements may contribute to the pathological events observed in the nervous system under disease conditions with a particular focus on Alzheimer's disease pathology.
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15
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Wang S, Yu L, Yang H, Li C, Hui Z, Xu Y, Zhu X. Oridonin Attenuates Synaptic Loss and Cognitive Deficits in an Aβ1-42-Induced Mouse Model of Alzheimer's Disease. PLoS One 2016; 11:e0151397. [PMID: 26974541 PMCID: PMC4790895 DOI: 10.1371/journal.pone.0151397] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 02/26/2016] [Indexed: 12/31/2022] Open
Abstract
Synaptic loss induced by beta-amyloid (Aβ) plays a critical role in the pathophysiology of Alzheimer’s disease (AD), but the mechanisms underlying this process remain unknown. In this study, we found that oridonin (Ori) rescued synaptic loss induced by Aβ1–42in vivo and in vitro and attenuated the alterations in dendritic structure and spine density observed in the hippocampus of AD mice. In addition, Ori increased the expression of PSD-95 and synaptophysin and promoted mitochondrial activity in the synaptosomes of AD mice. Ori also activated the BDNF/TrkB/CREB signaling pathway in the hippocampus of AD mice. Furthermore, in the Morris water maze test, Ori reduced latency and searching distance and increased the number of platform crosses in AD mice. These data suggest that Ori might prevent synaptic loss and improve behavioral symptoms in Aβ1–42-induced AD mice.
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Affiliation(s)
- Sulei Wang
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Linjie Yu
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, PR China
| | - Hui Yang
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Chaosheng Li
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Zhen Hui
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, PR China
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, PR China
- Jiangsu Stroke Research Collaborative Group, Nanjing, PR China
- Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, PR China
- Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Nanjing, PR China
- * E-mail: (YX); (XLZ)
| | - Xiaolei Zhu
- Department of Neurology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, PR China
- * E-mail: (YX); (XLZ)
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16
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Herms J, Dorostkar MM. Dendritic Spine Pathology in Neurodegenerative Diseases. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2016; 11:221-50. [PMID: 26907528 DOI: 10.1146/annurev-pathol-012615-044216] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Substantial progress has been made toward understanding the neuropathology, genetic origins, and epidemiology of neurodegenerative diseases, including Alzheimer's disease; tauopathies, such as frontotemporal dementia; α-synucleinopathies, such as Parkinson's disease or dementia with Lewy bodies; Huntington's disease; and amyotrophic lateral sclerosis with dementia, as well as prion diseases. Recent evidence has implicated dendritic spine dysfunction as an important substrate of the pathogenesis of dementia in these disorders. Dendritic spines are specialized structures, extending from the neuronal processes, on which excitatory synaptic contacts are formed, and the loss of dendritic spines correlates with the loss of synaptic function. We review the literature that has implicated direct or indirect structural alterations at dendritic spines in the pathogenesis of major neurodegenerative diseases, focusing on those that lead to dementias such as Alzheimer's, Parkinson's, and Huntington's diseases, as well as frontotemporal dementia and prion diseases. We stress the importance of in vivo studies in animal models.
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Affiliation(s)
- Jochen Herms
- Center for Neuropathology and Prion Research, Ludwig Maximilian University, 81377 Munich, Germany; .,Munich Cluster for Systems Neurology, Ludwig Maximilian University, 81377 Munich, Germany.,German Center for Neurodegenerative Diseases, 81377 Munich, Germany
| | - Mario M Dorostkar
- Center for Neuropathology and Prion Research, Ludwig Maximilian University, 81377 Munich, Germany;
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17
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Abstract
Electron microscopy has enlarged the visual horizons of the morphological alterations in Alzheimer's disease (AD). Study of the mitochondria and Golgi apparatus in early cases of AD revealed the principal role that these important organelles play in the drama of pathogenic dialog of AD, substantially affecting energy production and supply, and protein trafficking in neurons and glia. In addition, study of the morphological alterations of the dendritic arbor, dendritic spines and neuronal synapses, which are associated with mitochondrial damage, may reasonably interpret the clinical phenomena of the irreversible decline of the mental faculties and an individual's personality changes. Electron microscopy also reveals the involvement of microvascular alterations in the etiopathogenic background of AD.
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18
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Aβ42-oligomer Interacting Peptide (AIP) neutralizes toxic amyloid-β42 species and protects synaptic structure and function. Sci Rep 2015; 5:15410. [PMID: 26510576 PMCID: PMC4625140 DOI: 10.1038/srep15410] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 09/22/2015] [Indexed: 12/21/2022] Open
Abstract
The amyloid-β42 (Aβ42) peptide is believed to be the main culprit in the pathogenesis of Alzheimer disease (AD), impairing synaptic function and initiating neuronal degeneration. Soluble Aβ42 oligomers are highly toxic and contribute to progressive neuronal dysfunction, loss of synaptic spine density, and affect long-term potentiation (LTP). We have characterized a short, L-amino acid Aβ-oligomer Interacting Peptide (AIP) that targets a relatively well-defined population of low-n Aβ42 oligomers, rather than simply inhibiting the aggregation of Aβ monomers into oligomers. Our data show that AIP diminishes the loss of Aβ42-induced synaptic spine density and rescues LTP in organotypic hippocampal slice cultures. Notably, the AIP enantiomer (comprised of D-amino acids) attenuated the rough-eye phenotype in a transgenic Aβ42 fly model and significantly improved the function of photoreceptors of these flies in electroretinography tests. Overall, our results indicate that specifically “trapping” low-n oligomers provides a novel strategy for toxic Aβ42-oligomer recognition and removal.
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19
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Shelton MA, Newman JT, Gu H, Sampson AR, Fish KN, MacDonald ML, Moyer CE, DiBitetto JV, Dorph-Petersen KA, Penzes P, Lewis DA, Sweet RA. Loss of Microtubule-Associated Protein 2 Immunoreactivity Linked to Dendritic Spine Loss in Schizophrenia. Biol Psychiatry 2015; 78:374-85. [PMID: 25818630 PMCID: PMC4520801 DOI: 10.1016/j.biopsych.2014.12.029] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 11/25/2014] [Accepted: 12/19/2014] [Indexed: 02/05/2023]
Abstract
BACKGROUND Microtubule-associated protein 2 (MAP2) is a neuronal protein that plays a role in maintaining dendritic structure through its interaction with microtubules. In schizophrenia (Sz), numerous studies have revealed that the typically robust immunoreactivity (IR) of MAP2 is significantly reduced across several cortical regions. The relationship between MAP2-IR reduction and lower dendritic spine density, which is frequently reported in Sz, has not been explored in previous studies, and MAP2-IR loss has not been investigated in the primary auditory cortex (Brodmann area 41), a site of conserved pathology in Sz. METHODS Using quantitative spinning disk confocal microscopy in two cohorts of subjects with Sz and matched control subjects (Sz subjects, n = 20; control subjects, n = 20), we measured MAP2-IR and dendritic spine density and spine number in deep layer 3 of BA41. RESULTS Subjects with Sz exhibited a significant reduction in MAP2-IR. The reductions in MAP2-IR were not associated with neuron loss, loss of MAP2 protein, clinical confounders, or technical factors. Dendritic spine density and number also were reduced in Sz and correlated with MAP2-IR. In 12 (60%) subjects with Sz, MAP2-IR values were lower than the lowest values in control subjects; only in this group were spine density and number significantly reduced. CONCLUSIONS These findings demonstrate that MAP2-IR loss is closely linked to dendritic spine pathology in Sz. Because MAP2 shares substantial sequence, regulatory, and functional homology with MAP tau, the wealth of knowledge regarding tau biology and the rapidly expanding field of tau therapeutics provide resources for identifying how MAP2 is altered in Sz and possible leads to novel therapeutics.
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Affiliation(s)
- Micah A Shelton
- Translational Neuroscience Program, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Jason T Newman
- Translational Neuroscience Program, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Hong Gu
- Department of Statistics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Allan R Sampson
- Department of Statistics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Kenneth N Fish
- Translational Neuroscience Program, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Matthew L MacDonald
- Translational Neuroscience Program, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Caitlin E Moyer
- Translational Neuroscience Program, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - James V DiBitetto
- Translational Neuroscience Program, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Karl-Anton Dorph-Petersen
- Translational Neuroscience Program, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Aarhus, Denmark
| | - Peter Penzes
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - David A Lewis
- Translational Neuroscience Program, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Robert A Sweet
- Translational Neuroscience Program, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Mental Illness Research, Education, and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania.
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20
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Baloyannis SJ, Mavroudis I, Mitilineos D, Baloyannis IS, Costa VG. The hypothalamus in Alzheimer's disease: a Golgi and electron microscope study. Am J Alzheimers Dis Other Demen 2015; 30:478-87. [PMID: 25380804 PMCID: PMC10852817 DOI: 10.1177/1533317514556876] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder, characterized by irreversible decline of mental faculties, emotional and behavioral changes, loss of motor skills, and dysfunction of autonomic nervous system and disruption of circadian rhythms (CRs). We attempted to describe the morphological findings of the hypothalamus in early cases of AD, focusing our study mostly on the suprachiasmatic nucleus (SCN), the supraoptic nucleus (SON), and the paraventricular nucleus (PVN). Samples were processed for electron microscopy and silver impregnation techniques. The hypothalamic nuclei demonstrated a substantial decrease in the neuronal population, which was particularly prominent in the SCN. Marked abbreviation of dendritic arborization, in association with spinal pathology, was also seen. The SON and PVN demonstrated a substantial number of dystrophic axons and abnormal spines. Alzheimer's pathology, such as deposits of amyloid-β peptide and neurofibrillary degeneration, was minimal. Electron microscopy revealed mitochondrial alterations in the cell body and the dendritic branches. The morphological alterations of the hypothalamic nuclei in early cases of AD may be related to the gradual alteration of CRs and the instability of autonomic regulation.
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Affiliation(s)
- Stavros J Baloyannis
- Department of Neurology, Laboratory of Neuropathology and Electron Microscopy, Aristotelian University, Thessaloniki, Greece Laboratory of Neuropathology, Institute for Research on Alzheimer's Disease, Iraklion, Greece
| | - Ioannis Mavroudis
- Department of Neurology, Laboratory of Neuropathology and Electron Microscopy, Aristotelian University, Thessaloniki, Greece
| | - Demetrios Mitilineos
- Department of Neurology, Laboratory of Neuropathology and Electron Microscopy, Aristotelian University, Thessaloniki, Greece
| | - Ioannis S Baloyannis
- Department of Neurology, Laboratory of Neuropathology and Electron Microscopy, Aristotelian University, Thessaloniki, Greece
| | - Vassiliki G Costa
- Department of Neurology, Laboratory of Neuropathology and Electron Microscopy, Aristotelian University, Thessaloniki, Greece Laboratory of Neuropathology, Institute for Research on Alzheimer's Disease, Iraklion, Greece
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21
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Dorostkar MM, Zou C, Blazquez-Llorca L, Herms J. Analyzing dendritic spine pathology in Alzheimer's disease: problems and opportunities. Acta Neuropathol 2015; 130:1-19. [PMID: 26063233 PMCID: PMC4469300 DOI: 10.1007/s00401-015-1449-5] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 06/02/2015] [Accepted: 06/02/2015] [Indexed: 12/22/2022]
Abstract
Synaptic failure is an immediate cause of cognitive decline and memory dysfunction in Alzheimer’s disease. Dendritic spines are specialized structures on neuronal processes, on which excitatory synaptic contacts take place and the loss of dendritic spines directly correlates with the loss of synaptic function. Dendritic spines are readily accessible for both in vitro and in vivo experiments and have, therefore, been studied in great detail in Alzheimer’s disease mouse models. To date, a large number of different mechanisms have been proposed to cause dendritic spine dysfunction and loss in Alzheimer’s disease. For instance, amyloid beta fibrils, diffusible oligomers or the intracellular accumulation of amyloid beta have been found to alter the function and structure of dendritic spines by distinct mechanisms. Furthermore, tau hyperphosphorylation and microglia activation, which are thought to be consequences of amyloidosis in Alzheimer’s disease, may also contribute to spine loss. Lastly, genetic and therapeutic interventions employed to model the disease and elucidate its pathogenetic mechanisms in experimental animals may cause alterations of dendritic spines on their own. However, to date none of these mechanisms have been translated into successful therapeutic approaches for the human disease. Here, we critically review the most intensely studied mechanisms of spine loss in Alzheimer’s disease as well as the possible pitfalls inherent in the animal models of such a complex neurodegenerative disorder.
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Affiliation(s)
- Mario M. Dorostkar
- />Ludwig-Maximilians University Munich, Center for Neuropathology and Prion Research, Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Chengyu Zou
- />Ludwig-Maximilians University Munich, Center for Neuropathology and Prion Research, Feodor-Lynen-Str. 23, 81377 Munich, Germany
- />Graduate School of Systemic Neuroscience, Ludwig-Maximilians-University Munich, Munich, Germany
- />German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Lidia Blazquez-Llorca
- />Ludwig-Maximilians University Munich, Center for Neuropathology and Prion Research, Feodor-Lynen-Str. 23, 81377 Munich, Germany
- />German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Jochen Herms
- />German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany
- />Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
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22
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Oikawa N, Matsubara T, Fukuda R, Yasumori H, Hatsuta H, Murayama S, Sato T, Suzuki A, Yanagisawa K. Imbalance in fatty-acid-chain length of gangliosides triggers Alzheimer amyloid deposition in the precuneus. PLoS One 2015; 10:e0121356. [PMID: 25798597 PMCID: PMC4370507 DOI: 10.1371/journal.pone.0121356] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 01/30/2015] [Indexed: 12/26/2022] Open
Abstract
Amyloid deposition, a crucial event of Alzheimer's disease (AD), emerges in distinct brain regions. A key question is what triggers the assembly of the monomeric amyloid ß-protein (Aß) into fibrils in the regions. On the basis of our previous findings that gangliosides facilitate the initiation of Aß assembly at presynaptic neuritic terminals, we investigated how lipids, including gangliosides, cholesterol and sphingomyelin, extracted from synaptic plasma membranes (SPMs) isolated from autopsy brains were involved in the Aß assembly. We focused on two regions of the cerebral cortex; precuneus and calcarine cortex, one of the most vulnerable and one of the most resistant regions to amyloid deposition, respectively. Here, we show that lipids extracted from SPMs isolated from the amyloid-bearing precuneus, but neither the amyloid-free precuneus nor the calcarine cortex, markedly accelerate the Aß assembly in vitro. Through liquid chromatography-mass spectrometry of the lipids, we identified an increase in the ratio of the level of GD1b-ganglioside containing C20:0 fatty acid to that containing C18:0 as a cause of the enhanced Aß assembly in the precuneus. Our results suggest that the local glycolipid environment play a critical role in the initiation of Alzheimer amyloid deposition.
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Affiliation(s)
- Naoto Oikawa
- Department of Drug Discovery, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Aichi, Japan
| | - Teruhiko Matsubara
- Department of Bioscience and Informatics, Keio University, Kanagawa, Japan
| | - Ryoto Fukuda
- Department of Bioscience and Informatics, Keio University, Kanagawa, Japan
| | - Hanaki Yasumori
- Department of Bioscience and Informatics, Keio University, Kanagawa, Japan
| | - Hiroyuki Hatsuta
- Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Shigeo Murayama
- Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Toshinori Sato
- Department of Bioscience and Informatics, Keio University, Kanagawa, Japan
| | - Akemi Suzuki
- Institute of Glycoscience, Tokai University, Kanagawa, Japan
| | - Katsuhiko Yanagisawa
- Department of Drug Discovery, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Aichi, Japan
- Department of Alzheimer’s Disease Research, Center for Development of Advanced Medicine for Dementia, National Center for Geriatrics and Gerontology, Aichi, Japan
- * E-mail:
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Moyer CE, Erickson SL, Fish KN, Thiels E, Penzes P, Sweet RA. Developmental Trajectories of Auditory Cortex Synaptic Structures and Gap-Prepulse Inhibition of Acoustic Startle Between Early Adolescence and Young Adulthood in Mice. Cereb Cortex 2015; 26:2115-26. [PMID: 25759333 DOI: 10.1093/cercor/bhv040] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Cortical excitatory and inhibitory synapses are disrupted in schizophrenia, the symptoms of which often emerge during adolescence, when cortical excitatory synapses undergo pruning. In auditory cortex, a brain region implicated in schizophrenia, little is known about the development of excitatory and inhibitory synapses between early adolescence and young adulthood, and how these changes impact auditory cortex function. We used immunohistochemistry and quantitative fluorescence microscopy to quantify dendritic spines and GAD65-expressing inhibitory boutons in auditory cortex of early adolescent, late adolescent, and young adult mice. Numbers of spines decreased between early adolescence and young adulthood, during which time responses increased in an auditory cortex-dependent sensory task, silent gap-prepulse inhibition of the acoustic startle reflex (gap-PPI). Within-bouton GAD65 protein and GAD65-expressing bouton numbers decreased between late adolescence and young adulthood, a delay in onset relative to spine and gap-PPI changes. In mice lacking the spine protein kalirin, there were no significant changes in spine number, within-bouton GAD65 protein, or gap-PPI between adolescence and young adulthood. These results illustrate developmental changes in auditory cortex spines, inhibitory boutons, and auditory cortex function between adolescence and young adulthood, and provide insights into how disrupted adolescent neurodevelopment could contribute to auditory cortex synapse pathology and auditory impairments.
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Affiliation(s)
- Caitlin E Moyer
- Center for Neuroscience Translational Neuroscience Program, Department of Psychiatry
| | | | - Kenneth N Fish
- Center for Neuroscience Translational Neuroscience Program, Department of Psychiatry
| | - Edda Thiels
- Center for Neuroscience Department of Neurobiology
| | - Peter Penzes
- Department of Physiology Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Robert A Sweet
- Center for Neuroscience Translational Neuroscience Program, Department of Psychiatry Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA Mental Illness Research, Education, and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA, USA
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Finch CE, Austad SN. Commentary: is Alzheimer's disease uniquely human? Neurobiol Aging 2014; 36:553-5. [PMID: 25533426 DOI: 10.1016/j.neurobiolaging.2014.10.025] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/16/2014] [Indexed: 11/17/2022]
Abstract
That Alzheimer's disease (AD) might be a human-specific disease was hypothesized by Rapoport in 1989. Apes and humans share an identical amyloid beta (Aβ) peptide amino acid sequence and accumulate considerable Aβ deposits after age 40 years, an age when amyloid plaques are uncommon in humans. Despite their early Aβ buildup, ape brains have not shown evidence dystrophic neurites near plaques. Aging great ape brains also have few neurofibrillary tangles, with one exception of 1 obese chimpanzee euthanized after a stroke who displayed abundant neurofibrillary tangles, but without the typical AD distribution. We discuss the need for more exacting evaluation of neuron density with age, and note husbandry issues that may allow great apes to live to greater ages. We remain reserved about expectations for fully developed AD-like pathology in the great apes of advanced ages and cautiously support Rapoport's hypothesis.
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Affiliation(s)
- Caleb E Finch
- Davis School of Gerontology and Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.
| | - Steven N Austad
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL, USA
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25
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Dorostkar MM, Burgold S, Filser S, Barghorn S, Schmidt B, Anumala UR, Hillen H, Klein C, Herms J. Immunotherapy alleviates amyloid-associated synaptic pathology in an Alzheimer's disease mouse model. ACTA ACUST UNITED AC 2014; 137:3319-26. [PMID: 25281869 PMCID: PMC4240293 DOI: 10.1093/brain/awu280] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Accumulation of amyloid-beta leads to loss of functional synapses in Alzheimer’s disease. Dorostkar et al. report that immunotherapy against oligomeric amyloid-beta in the Tg2576 mouse model attenuates synapse loss near plaques, and abolishes it elsewhere. Sequestering oligomeric amyloid-beta may counteract synaptic pathology, even while fibrillar amyloid load remains unchanged. Cognitive decline in Alzheimer’s disease is attributed to loss of functional synapses, most likely caused by synaptotoxic, oligomeric forms of amyloid-β. Many treatment options aim at reducing amyloid-β levels in the brain, either by decreasing its production or by increasing its clearance. We quantified the effects of immunotherapy directed against oligomeric amyloid-β in Tg2576 mice, a mouse model of familial Alzheimer’s disease. Treatment of 12-month-old mice with oligomer-specific (A-887755) or conformation-unspecific (6G1) antibodies for 8 weeks did not affect fibrillar plaque density or growth. We also quantified densities of DLG4 (previously known as PSD95) expressing post-synapses and synapsin expressing presynapses immunohistochemically. We found that both pre- and post-synapses were strongly reduced in the vicinity of plaques, whereas distant from plaques, in the cortex and hippocampal CA1 field, only post-synapses were reduced. Immunotherapy alleviated this synapse loss. Synapse loss was completely abolished distant from plaques, whereas it was only attenuated in the vicinity of plaques. These results suggest that fibrillar plaques may act as reservoirs for synaptotoxic, oligomeric amyloid-β and that sequestering oligomers suffices to counteract synaptic pathology. Therefore, cognitive function may be improved by immunotherapy even when the load of fibrillar amyloid remains unchanged.
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Affiliation(s)
- Mario M Dorostkar
- 1 Centre for Neuropathology and Prion Research, Ludwig Maximilian University, Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Steffen Burgold
- 1 Centre for Neuropathology and Prion Research, Ludwig Maximilian University, Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Severin Filser
- 2 Department of Translational Brain Research, German Centre for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany
| | - Stefan Barghorn
- 3 AbbVie Deutschland GmbH and Co. KG, Neuroscience Discovery Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Boris Schmidt
- 4 Clemens Schoepf-Institute for Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Petersenstrasse 22, 64287 Darmstadt, Germany
| | - Upendra Rao Anumala
- 4 Clemens Schoepf-Institute for Organic Chemistry and Biochemistry, Technische Universität Darmstadt, Petersenstrasse 22, 64287 Darmstadt, Germany
| | - Heinz Hillen
- 3 AbbVie Deutschland GmbH and Co. KG, Neuroscience Discovery Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Corinna Klein
- 3 AbbVie Deutschland GmbH and Co. KG, Neuroscience Discovery Research, Knollstrasse, 67061 Ludwigshafen, Germany
| | - Jochen Herms
- 1 Centre for Neuropathology and Prion Research, Ludwig Maximilian University, Feodor-Lynen-Str. 23, 81377 Munich, Germany 2 Department of Translational Brain Research, German Centre for Neurodegenerative Diseases (DZNE), Feodor-Lynen-Str. 23, 81377 Munich, Germany 5 Munich Cluster of Systems Neurology (SyNergy), Ludwig Maximilian University, Schillerstraße 44, 80336 Munich, Germany
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Afanador L, Roltsch EA, Holcomb L, Campbell KS, Keeling DA, Zhang Y, Zimmer DB. The Ca2+ sensor S100A1 modulates neuroinflammation, histopathology and Akt activity in the PSAPP Alzheimer's disease mouse model. Cell Calcium 2014; 56:68-80. [DOI: 10.1016/j.ceca.2014.05.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 05/15/2014] [Accepted: 05/16/2014] [Indexed: 11/25/2022]
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27
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Simultaneous changes of spatial memory and spine density after intrahippocampal administration of fibrillar aβ1-42 to the rat brain. BIOMED RESEARCH INTERNATIONAL 2014; 2014:345305. [PMID: 25050342 PMCID: PMC4094878 DOI: 10.1155/2014/345305] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Revised: 05/25/2014] [Accepted: 06/02/2014] [Indexed: 01/29/2023]
Abstract
Several animal models of Alzheimer's disease have been used in laboratory experiments. Intrahippocampal injection of fibrillar amyloid-beta (fAβ) peptide represents one of the most frequently used models, mimicking Aβ deposits in the brain. In our experiment synthetic fAβ1–42 peptide was administered to rat hippocampus. The effect of the Aβ peptide on spatial memory and dendritic spine density was studied. The fAβ1–42-treated rats showed decreased spatial learning ability measured in Morris water maze (MWM). Simultaneously, fAβ1–42 caused a significant reduction of the dendritic spine density in the rat hippocampus CA1 region. The decrease of learning ability and the loss of spine density were in good correlation. Our results prove that both methods (MWM and dendritic spine density measurement) are suitable for studying Aβ-triggered neurodegeneration processes.
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Rosenblum WI. Why Alzheimer trials fail: removing soluble oligomeric beta amyloid is essential, inconsistent, and difficult. Neurobiol Aging 2014; 35:969-74. [DOI: 10.1016/j.neurobiolaging.2013.10.085] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 10/14/2013] [Accepted: 10/16/2013] [Indexed: 01/08/2023]
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