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Tumanova NL, Vasilev DS, Dubrovskaya NM, Nalivaeva NN. Neurodegenerative Changes in the Structural and Ultrastructural Organization in the Pyriform Cortex of 5xFAD Transgenic Mice. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022040251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Chithanathan K, Xuan FL, Hickey MA, Tian L. Enhanced Anxiety and Olfactory Microglial Activation in Early-Stage Familial Alzheimer's Disease Mouse Model. BIOLOGY 2022; 11:biology11060938. [PMID: 35741458 PMCID: PMC9219751 DOI: 10.3390/biology11060938] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/15/2022] [Accepted: 06/15/2022] [Indexed: 04/30/2023]
Abstract
Anxiety is a known comorbidity and risk factor for conversion to neuroinflammation-mediated dementia in patients with Alzheimer's disease (AD). Here, we investigated if anxiety occurred as an early endophenotype of mutant familial AD (5 × FAD) male mice and the underlying neuroinflammatory mechanisms. We observed that compared to wildtype (WT) littermates, 5 × FAD mice showed enhanced anxiety at as early as 2 months old (mo). Interestingly, these 5 × FAD male mice had concomitantly increased mRNA levels of pro-inflammatory cytokines such as interleukin 1 beta (Il1b) and tumor necrosis factor (Tnf) in the olfactory bulb (OB) but not the frontal cortex (FC). Increased expression of Tnf in the OB was significantly correlated with the anxious behavior in the FAD but not WT mice. Furthermore, we found more prominent microglial activation and morphological changes in the OB of 2 mo 5 × FAD mice, while only microglial ramification was seen in the FC. To understand if neuroinflammatory changes in the FC could occur at a later stage, we studied 5~6 mo male mice and found that Il1b, interleukin 18 (Il18), and Tnf were upregulated in the FC at this older age. Furthermore, we observed that numbers of microglia and macrophage as well as microglial synaptic pruning, as indicated by phagocytosis of presynaptic component of vesicular glutamate transporter-2, were increased in the OB but not the FC of 5~6 mo 5 × FAD mice. Our findings demonstrated the OB as a more sensitive brain region than the cerebral cortex for microglia-mediated neuroinflammation in association with anxiety in FAD mice and supported the notion that the OB can be an early-stage biomarker in AD.
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Affiliation(s)
- Keerthana Chithanathan
- Department of Physiology, Faculty of Medicine, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 14b, 50411 Tartu, Estonia; (K.C.); (F.-L.X.)
| | - Fang-Ling Xuan
- Department of Physiology, Faculty of Medicine, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 14b, 50411 Tartu, Estonia; (K.C.); (F.-L.X.)
| | - Miriam Ann Hickey
- Department of Pharmacology, Faculty of Medicine, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 19, 50411 Tartu, Estonia;
| | - Li Tian
- Department of Physiology, Faculty of Medicine, Institute of Biomedicine and Translational Medicine, University of Tartu, Ravila 14b, 50411 Tartu, Estonia; (K.C.); (F.-L.X.)
- Correspondence:
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3
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Olfactory Evaluation in Alzheimer’s Disease Model Mice. Brain Sci 2022; 12:brainsci12050607. [PMID: 35624994 PMCID: PMC9139301 DOI: 10.3390/brainsci12050607] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/26/2022] [Accepted: 05/03/2022] [Indexed: 11/17/2022] Open
Abstract
Olfactory dysfunction is considered a pre-cognitive biomarker of Alzheimer’s disease (AD). Because the olfactory system is highly conserved across species, mouse models corresponding to various AD etiologies have been bred and used in numerous studies on olfactory disorders. The olfactory behavior test is a method required for early olfactory dysfunction detection in AD model mice. Here, we review the olfactory evaluation of AD model mice, focusing on traditional olfactory detection methods, olfactory behavior involving the olfactory cortex, and the results of olfactory behavior in AD model mice, aiming to provide some inspiration for further development of olfactory detection methods in AD model mice.
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4
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Ziegler-Waldkirch S, Friesen M, Loreth D, Sauer JF, Kemna S, Hilse A, Erny D, Helm C, d´Errico P, Prinz M, Bartos M, Meyer-Luehmann M. Seed-induced Aβ deposition alters neuronal function and impairs olfaction in a mouse model of Alzheimer's disease. Mol Psychiatry 2022; 27:4274-4284. [PMID: 35869271 PMCID: PMC9718674 DOI: 10.1038/s41380-022-01686-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 02/07/2023]
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of amyloid-β (Aβ) which ultimately forms plaques. These Aβ deposits can be induced in APP transgenic mouse models by prion-like seeding. It has been widely accepted that anosmia and hyposmia occur during the early stages of AD, even before cognitive deficits are present. In order to determine the impact of seed-induced Aβ deposits on olfaction, we performed intracerebral injections of seed-competent brain homogenate into the olfactory bulb of young pre-depositing APP transgenic mice. Remarkably, we observed a dramatic olfactory impairment in those mice. Furthermore, the number of newborn neurons as well as the activity of cells in the mitral cell layer was decreased. Notably, exposure to an enriched environment reduced Aβ seeding, vivified neurogenesis and most importantly reversed olfactory deficits. Based on our findings, we conclude that altered neuronal function as a result of induced Aβ pathology might contribute to olfactory dysfunction in AD.
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Affiliation(s)
- Stephanie Ziegler-Waldkirch
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Marina Friesen
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Faculty of Biology, University of Freiburg, 79110 Freiburg, Germany
| | - Desirée Loreth
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.13648.380000 0001 2180 3484Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Jonas-Frederic Sauer
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, 79104 Freiburg, Germany
| | - Solveig Kemna
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Alexandra Hilse
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Faculty of Biology, University of Freiburg, 79110 Freiburg, Germany
| | - Daniel Erny
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute of Neuropathology, University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Christina Helm
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Paolo d´Errico
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Marco Prinz
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute of Neuropathology, University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany
| | - Marlene Bartos
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, 79104 Freiburg, Germany ,grid.5963.9Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine University of Freiburg, 79110 Freiburg, Germany
| | - Melanie Meyer-Luehmann
- Department of Neurology, Medical Center - University of Freiburg, 79106, Freiburg, Germany. .,Faculty of Medicine, University of Freiburg, 79110, Freiburg, Germany. .,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine University of Freiburg, 79110, Freiburg, Germany.
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5
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Tzeng WY, Figarella K, Garaschuk O. Olfactory impairment in men and mice related to aging and amyloid-induced pathology. Pflugers Arch 2021; 473:805-821. [PMID: 33608800 PMCID: PMC7895745 DOI: 10.1007/s00424-021-02527-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 01/07/2021] [Accepted: 01/28/2021] [Indexed: 12/31/2022]
Abstract
Olfaction, or the sense of smell, is one of the most ancient senses in men and mice, important for a large variety of innate and acquired behaviors. Clinical data reveal an early impairment of olfaction during normal aging and in the course of neurodegenerative diseases, but the underlying cellular/molecular mechanisms remain obscure. In the current review, we compare different aspects of the aging- and Alzheimer's disease related impairment of olfaction in men and mice, aiming at the identification of common morbidities and biomarkers, which can be analyzed in detail in the appropriate mouse models. We also identify common, often interdependent (patho)physiological pathways, including but not limited to extracellular amyloid depositions, neuroinflammation, ɛ4 allele of the apolipoprotein E, CNS insulin resistance, and the impairment of adult neurogenesis, to be targeted by basic and clinical research.
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Affiliation(s)
- Wen-Yu Tzeng
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
| | - Katherine Figarella
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany
| | - Olga Garaschuk
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Keplerstr. 15, 72074, Tübingen, Germany.
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6
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O'Leary TP, Stover KR, Mantolino HM, Darvesh S, Brown RE. Intact olfactory memory in the 5xFAD mouse model of Alzheimer's disease from 3 to 15 months of age. Behav Brain Res 2020; 393:112731. [PMID: 32522622 DOI: 10.1016/j.bbr.2020.112731] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/18/2020] [Accepted: 05/23/2020] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is an age-related neurodegenerative disorder that causes profound cognitive dysfunction. Deficits in olfactory memory occur in early stages of AD and may be useful in AD diagnosis. The 5xFAD mouse is a commonly used model of AD, as it develops neuropathology, cognitive and sensori-motor dysfunctions similar to those seen in AD. However, olfactory memory dysfunction has not been studied adequately or in detail in 5xFAD mice. Furthermore, despite sex differences in AD prevalence and symptom presentation, few studies using 5xFAD mice have examined sex differences in learning and memory. Therefore, we tested olfactory memory in male and female 5xFAD mice from 3 to 15 months of age using a conditioned odour preference task. Olfactory memory was not impaired in male or female 5xFAD mice at any age tested, nor were there any sex differences. Because early-onset impairments in very long-term (remote) memory have been reported in 5xFAD mice, we trained a group of mice at 3 months of age and tested olfactory memory 90 days later. Very long-term olfactory memory in 5xFAD mice was not impaired, nor was their ability to perform the discrimination task with new odourants. Examination of brains from 5xFAD mice confirmed extensive Aβ-plaque deposition spanning the olfactory memory system, including the olfactory bulb, hippocampus, amygdala and piriform cortex. Overall this study indicates that male and female 5xFAD mice do not develop olfactory memory deficits, despite extensive Aβ deposition within the olfactory-memory regions of the brain.
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Affiliation(s)
- T P O'Leary
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - K R Stover
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - H M Mantolino
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - S Darvesh
- Department of Medicine (Neurology) and Medical Neuroscience, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - R E Brown
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, B3H 4R2, Canada.
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7
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Dibattista M, Pifferi S, Menini A, Reisert J. Alzheimer's Disease: What Can We Learn From the Peripheral Olfactory System? Front Neurosci 2020; 14:440. [PMID: 32508565 PMCID: PMC7248389 DOI: 10.3389/fnins.2020.00440] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/09/2020] [Indexed: 01/01/2023] Open
Abstract
The sense of smell has been shown to deteriorate in patients with some neurodegenerative disorders. In Parkinson's disease (PD) and Alzheimer's disease (AD), decreased ability to smell is associated with early disease stages. Thus, olfactory neurons in the nose and olfactory bulb (OB) may provide a window into brain physiology and pathophysiology to address the pathogenesis of neurodegenerative diseases. Because nasal olfactory receptor neurons regenerate throughout life, the olfactory system offers a broad variety of cellular mechanisms that could be altered in AD, including odorant receptor expression, neurogenesis and neurodegeneration in the olfactory epithelium, axonal targeting to the OB, and synaptogenesis and neurogenesis in the OB. This review focuses on pathophysiological changes in the periphery of the olfactory system during the progression of AD in mice, highlighting how the olfactory epithelium and the OB are particularly sensitive to changes in proteins and enzymes involved in AD pathogenesis. Evidence reviewed here in the context of the emergence of other typical pathological changes in AD suggests that olfactory impairments could be used to understand the molecular mechanisms involved in the early phases of the pathology.
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Affiliation(s)
- Michele Dibattista
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, University of Bari A. Moro, Bari, Italy
| | - Simone Pifferi
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy
| | - Anna Menini
- Neurobiology Group, SISSA, Scuola Internazionale Superiore di Studi Avanzati, Trieste, Italy
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8
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Franks KH, Chuah MI, King AE, Vickers JC. Connectivity of Pathology: The Olfactory System as a Model for Network-Driven Mechanisms of Alzheimer's Disease Pathogenesis. Front Aging Neurosci 2015; 7:234. [PMID: 26696886 PMCID: PMC4678206 DOI: 10.3389/fnagi.2015.00234] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 11/30/2015] [Indexed: 11/24/2022] Open
Abstract
The pathogenesis of Alzheimer’s disease (AD) has been postulated to preferentially impact specific neural networks in the brain. The olfactory system is a well-defined network that has been implicated in early stages of the disease, marked by impairment in olfaction and the presence of pathological hallmarks of the disease, even before clinical presentation. Discovering the cellular mechanisms involved in the connectivity of pathology will provide insight into potential targets for treatment. We review evidence from animal studies on sensory alteration through denervation or enrichment, which supports the notion of using the olfactory system to investigate the implications of connectivity and activity in the spread of pathology in AD.
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Affiliation(s)
- Katherine H Franks
- Faculty of Health, Wicking Dementia Research and Education Centre, University of Tasmania , Hobart, TAS , Australia
| | - Meng Inn Chuah
- Faculty of Health, Wicking Dementia Research and Education Centre, University of Tasmania , Hobart, TAS , Australia
| | - Anna E King
- Faculty of Health, Wicking Dementia Research and Education Centre, University of Tasmania , Hobart, TAS , Australia
| | - James C Vickers
- Faculty of Health, Wicking Dementia Research and Education Centre, University of Tasmania , Hobart, TAS , Australia
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9
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Saiz-Sanchez D, Flores-Cuadrado A, Ubeda-Bañon I, de la Rosa-Prieto C, Martinez-Marcos A. Interneurons in the human olfactory system in Alzheimer's disease. Exp Neurol 2015; 276:13-21. [PMID: 26616239 DOI: 10.1016/j.expneurol.2015.11.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 11/12/2015] [Accepted: 11/21/2015] [Indexed: 01/09/2023]
Abstract
The principal olfactory structures display Alzheimer's disease (AD) related pathology at early stages of the disease. Consequently, olfactory deficits are among the earliest symptoms. Reliable olfactory tests for accurate clinical diagnosis are rarely made. In addition, neuropathological analysis postmortem of olfactory structures is often not made. Therefore, the relationship between the clinical features and the underlying pathology is poorly defined. Traditionally, research into Alzheimer's disease has focused on the degeneration of cortical temporal projection neurons and cholinergic neurons. Recent evidence has demonstrated the neurodegeneration of interneuron populations in AD. This review provides an updated overview of the pathological involvement of interneuron populations in the human olfactory system in Alzheimer's disease.
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Affiliation(s)
- Daniel Saiz-Sanchez
- Laboratorio de Neuroplasticidad y Neurodegeneración, Facultad de Medicina de Ciudad Real, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, 13005 Ciudad Real, Spain
| | - Alicia Flores-Cuadrado
- Laboratorio de Neuroplasticidad y Neurodegeneración, Facultad de Medicina de Ciudad Real, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, 13005 Ciudad Real, Spain
| | - Isabel Ubeda-Bañon
- Laboratorio de Neuroplasticidad y Neurodegeneración, Facultad de Medicina de Ciudad Real, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, 13005 Ciudad Real, Spain
| | - Carlos de la Rosa-Prieto
- Laboratorio de Neuroplasticidad y Neurodegeneración, Facultad de Medicina de Ciudad Real, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, 13005 Ciudad Real, Spain
| | - Alino Martinez-Marcos
- Laboratorio de Neuroplasticidad y Neurodegeneración, Facultad de Medicina de Ciudad Real, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, 13005 Ciudad Real, Spain.
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10
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Attems J, Walker L, Jellinger KA. Olfaction and Aging: A Mini-Review. Gerontology 2015; 61:485-90. [DOI: 10.1159/000381619] [Citation(s) in RCA: 162] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 03/12/2015] [Indexed: 11/19/2022] Open
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Daulatzai MA. Olfactory dysfunction: its early temporal relationship and neural correlates in the pathogenesis of Alzheimer’s disease. J Neural Transm (Vienna) 2015; 122:1475-97. [DOI: 10.1007/s00702-015-1404-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 04/29/2015] [Indexed: 12/18/2022]
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Yan XX, Ma C, Gai WP, Cai H, Luo XG. Can BACE1 inhibition mitigate early axonal pathology in neurological diseases? J Alzheimers Dis 2014; 38:705-18. [PMID: 24081378 DOI: 10.3233/jad-131400] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
β-Secretase-1 (BACE1) is the rate-limiting enzyme for the genesis of amyloid-β (Aβ) peptides, the main constituents of the amyloid plaques in the brains of Alzheimer's disease (AD) patients. BACE1 is being evaluated as an anti-Aβ target for AD therapy. Recent studies indicate that BACE1 elevation is associated with axonal and presynaptic pathology during plaque development. Evidence also points to a biological role for BACE1 in axonal outgrowth and synapse formation during development. Axonal, including presynaptic, pathology exists in AD as well as many other neurological disorders such as Parkinson's disease, epilepsy, stroke, and trauma. In this review, we discuss pharmaceutical BACE1 inhibition as a therapeutic option for axonal pathogenesis, in addition to amyloid pathology. We first introduce the amyloidogenic processing of amyloid-β protein precursor and describe the normal expression pattern of the amyloidogenic proteins in the brain, with an emphasis on BACE1. We then address BACE1 elevation relative to amyloid plaque development, followed by updating recent understanding of a neurotrophic role of BACE1 in axon and synapse development. We further elaborate the occurrence of axonal pathology in some other neurological conditions. Finally, we propose pharmacological inhibition of excessive BACE1 activity as an option to mitigate early axonal pathology occurring in AD and other neurological disorders.
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Affiliation(s)
- Xiao-Xin Yan
- Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan, China
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13
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Olfactory Dysfunction in the Elderly: Basic Circuitry and Alterations with Normal Aging and Alzheimer's Disease. CURRENT GERIATRICS REPORTS 2014; 3:91-100. [PMID: 25045620 DOI: 10.1007/s13670-014-0080-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Preclinical detection of Alzheimer disease is critical to determining at-risk individuals in order to improve patient and caregiver planning for their futures and to identify individuals likely to benefit from treatment as advances in therapeutics develop over time. Identification of olfactory dysfunction at the preclinical and early stages of the disease is a potentially useful method to accomplish these goals. We first review basic olfactory circuitry. We then evaluate the evidence of pathophysiological change in the olfactory processing pathways during aging and Alzheimer disease in both human and animal models. We also review olfactory behavioral studies during these processes in both types of models. In doing so, we suggest hypotheses about the localization and mechanisms of olfactory dysfunction and identify important avenues for future work.
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14
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Attems J, Walker L, Jellinger KA. Olfactory bulb involvement in neurodegenerative diseases. Acta Neuropathol 2014; 127:459-75. [PMID: 24554308 DOI: 10.1007/s00401-014-1261-7] [Citation(s) in RCA: 218] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 02/11/2014] [Accepted: 02/11/2014] [Indexed: 12/24/2022]
Abstract
Olfactory dysfunction is a common and early symptom of many neurodegenerative diseases, particularly of Parkinson's disease and other synucleinopathies, Alzheimer's disease (AD), and mild cognitive impairment heralding its progression to dementia. The neuropathologic changes of olfactory dysfunction in neurodegenerative diseases may involve the olfactory epithelium, olfactory bulb/tract, primary olfactory cortices, and their secondary targets. Olfactory dysfunction is related to deposition of pathological proteins, α-synuclein, hyperphosphorylated tau protein, and neurofilament protein in these areas, featured by neurofibrillary tangles, Lewy bodies and neurites inducing a complex cascade of molecular processes including oxidative damage, neuroinflammation, and cytosolic disruption of cellular processes leading to cell death. Damage to cholinergic, serotonergic, and noradrenergic systems is likely involved, since such damage is most marked in those diseases with severe anosmia. Recent studies of olfactory dysfunction have focused its potential as an early biomarker for the diagnosis of neurodegenerative disorders and their disease progression. Here, we summarize the current knowledge on neuropathological and pathophysiological changes of the olfactory system in the most frequent neurodegenerative diseases, in particular AD and synucleinopathies. We also present neuropathological findings in the olfactory bulb and tract in a large autopsy cohort (n = 536, 57.8 % female, mean age 81.3 years). The severity of olfactory bulb HPτ, Aβ, and αSyn pathology correlated and increased significantly (P < 0.001) with increasing neuritic Braak stages, Thal Aβ phases, and cerebral Lewy body pathology, respectively. Hence, further studies are warranted to investigate the potential role of olfactory biopsies (possibly restricted to the olfactory epithelium) in the diagnostic process of neurodegenerative diseases in particular in clinical drug trials to identify subjects showing early, preclinical stages of neurodegeneration and to stratify clinically impaired cohorts according to the underlying cerebral neuropathology.
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Affiliation(s)
- Johannes Attems
- Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
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15
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Abstract
The olfactory system has a rich cortical representation, including a large archicortical component present in most vertebrates, and in mammals neocortical components including the entorhinal and orbitofrontal cortices. Together, these cortical components contribute to normal odor perception and memory. They help transform the physicochemical features of volatile molecules inhaled or exhaled through the nose into the perception of odor objects with rich associative and hedonic aspects. This chapter focuses on how olfactory cortical areas contribute to odor perception and begins to explore why odor perception is so sensitive to disease and pathology. Odor perception is disrupted by a wide range of disorders including Alzheimer's disease, Parkinson's disease, schizophrenia, depression, autism, and early life exposure to toxins. This olfactory deficit often occurs despite maintained functioning in other sensory systems. Does the unusual network of olfactory cortical structures contribute to this sensitivity?
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16
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Saiz-Sanchez D, De La Rosa-Prieto C, Ubeda-Bañon I, Martinez-Marcos A. Interneurons and beta-amyloid in the olfactory bulb, anterior olfactory nucleus and olfactory tubercle in APPxPS1 transgenic mice model of Alzheimer's disease. Anat Rec (Hoboken) 2013; 296:1413-23. [PMID: 23904197 DOI: 10.1002/ar.22750] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 06/18/2013] [Indexed: 01/29/2023]
Abstract
Impaired olfaction has been described as an early symptom in Alzheimer's disease (AD). Neuroanatomical changes underlying this deficit in the olfactory system are largely unknown. Given that interneuron populations are crucial in olfactory information processing, we have quantitatively analyzed somatostatin- (SOM), parvalbumin- (PV), and calretinin-expressing (CR) cells in the olfactory bulb, anterior olfactory nucleus, and olfactory tubercle in PS1 x APP double transgenic mice model of AD. The experiments were performed in wild type and double transgenic homozygous animal groups of 2, 4, 6, and 8 months of age to analyze early stages of the pathology. In addition, beta-amyloid (Aβ) expression and its correlation with SOM cells have been quantified under confocal microscopy. The results indicate increasing expressions of Aβ with aging as well as an early fall of SOM and CR expression, whereas PV was decreased later in the disease progression. These observations evidence an early, preferential vulnerability of SOM and CR cells in rostral olfactory structures during AD that may be useful to unravel neural basis of olfactory deficits associated to this neurodegenerative disorder.
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Affiliation(s)
- Daniel Saiz-Sanchez
- Laboratorio de Neuroplasticidad y Neurodegeneración, Departamento de Ciencias Médicas, Centro Regional de Investigaciones Biomédicas, Facultad de Medicina de Ciudad Real, Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain
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Yan XX, Cai Y, Shelton J, Deng SH, Luo XG, Oddo S, LaFerla FM, Cai H, Rose GM, Patrylo PR. Chronic temporal lobe epilepsy is associated with enhanced Alzheimer-like neuropathology in 3×Tg-AD mice. PLoS One 2012; 7:e48782. [PMID: 23155407 PMCID: PMC3498246 DOI: 10.1371/journal.pone.0048782] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 10/01/2012] [Indexed: 11/18/2022] Open
Abstract
The comorbidity between epilepsy and Alzheimer's disease (AD) is a topic of growing interest. Senile plaques and tauopathy are found in epileptic human temporal lobe structures, and individuals with AD have an increased incidence of spontaneous seizures. However, why and how epilepsy is associated with enhanced AD-like pathology remains unknown. We have recently shown β-secretase-1 (BACE1) elevation associated with aberrant limbic axonal sprouting in epileptic CD1 mice. Here we sought to explore whether BACE1 upregulation affected the development of Alzheimer-type neuropathology in mice expressing mutant human APP, presenilin and tau proteins, the triple transgenic model of AD (3×Tg-AD). 3×Tg-AD mice were treated with pilocarpine or saline (i.p.) at 6-8 months of age. Immunoreactivity (IR) for BACE1, β-amyloid (Aβ) and phosphorylated tau (p-tau) was subsequently examined at 9, 11 or 14 months of age. Recurrent convulsive seizures, as well as mossy fiber sprouting and neuronal death in the hippocampus and limbic cortex, were observed in all epileptic mice. Neuritic plaques composed of BACE1-labeled swollen/sprouting axons and extracellular AβIR were seen in the hippocampal formation, amygdala and piriform cortices of 9 month-old epileptic, but not control, 3×Tg-AD mice. Densities of plaque-associated BACE1 and AβIR were elevated in epileptic versus control mice at 11 and 14 months of age. p-Tau IR was increased in dentate granule cells and mossy fibers in epileptic mice relative to controls at all time points examined. Thus, pilocarpine-induced chronic epilepsy was associated with accelerated and enhanced neuritic plaque formation and altered intraneuronal p-tau expression in temporal lobe structures in 3×Tg-AD mice, with these pathologies occurring in regions showing neuronal death and axonal dystrophy.
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Affiliation(s)
- Xiao-Xin Yan
- Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan, China
- * E-mail: (XXY); (GMR); (PRP)
| | - Yan Cai
- Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan, China
- Center for Integrated Research in Cognitive and Neural Sciences, Southern Illinois University Carbondale, Illinois, United States of America
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, Illinois, United States of America
| | - Jarod Shelton
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, Illinois, United States of America
| | - Si-Hao Deng
- Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan, China
| | - Xue-Gang Luo
- Department of Anatomy and Neurobiology, Central South University Xiangya School of Medicine, Changsha, Hunan, China
| | - Salvatore Oddo
- Department of Physiology and The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Frank M. LaFerla
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, California, United States of America
| | - Huaibin Cai
- Laboratory of Neurogenetics, National Institute on Aging, Bethesda, Maryland, United States of America
| | - Gregory M. Rose
- Center for Integrated Research in Cognitive and Neural Sciences, Southern Illinois University Carbondale, Illinois, United States of America
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, Illinois, United States of America
- * E-mail: (XXY); (GMR); (PRP)
| | - Peter R. Patrylo
- Center for Integrated Research in Cognitive and Neural Sciences, Southern Illinois University Carbondale, Illinois, United States of America
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, Illinois, United States of America
- * E-mail: (XXY); (GMR); (PRP)
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Amyloid plaque pathogenesis in 5XFAD mouse spinal cord: retrograde transneuronal modulation after peripheral nerve injury. Neurotox Res 2012; 24:1-14. [PMID: 23055086 DOI: 10.1007/s12640-012-9355-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 09/14/2012] [Accepted: 09/26/2012] [Indexed: 12/25/2022]
Abstract
The spinal cord is composed of distinct neuronal groups with well-defined anatomic connections. In some transgenic (Tg) models of Alzheimer's disease (AD), amyloid plaques develop in this structure, although the underlying cellular mechanism remains elusive. We attempted to explore the origin, evolution, and modulation of spinal β-amyloid (Aβ) deposition using Tg mice harboring five familiar AD-related mutations (5XFAD) as an experiential model. Dystrophic neuritic elements with enhanced β-secretase-1 (BACE1) immunoreactivity (IR) appeared as early as 2 months of age, and increased with age up to 12 months examined in this study, mostly over the ventral horn (VH). Extracellular Aβ IR emerged and developed during this same period, site-specifically co-existing with BACE1-labeled neurites often in the vicinity of large VH neurons that expressed the mutant human APP. The BACE1-labeled neurites almost invariably colocalized with β-amyloid precursor protein (APP) and synaptophysin, and frequently with the vesicular glutamate transporter-1 (VGLUT). Reduced IR for the neuronal-specific nuclear antigen (NeuN) occurred in the VH by 12 months of age. In 8-month-old animals surviving 6 months after a unilateral sciatic nerve transection, there were significant increases of Aβ, BACE1, and VGLUT IR in the VN of the ipsilateral relative to contralateral lumbar spinal segments. These results suggest that extracellular Aβ deposition in 5XFAD mouse spinal cord relates to a progressive and amyloidogenic synaptic pathology largely involving presynaptic axon terminals from projection neurons in the brain. Spinal neuritic plaque formation is enhanced after peripheral axotomy, suggesting a retrograde transneuronal modulation on pathogenesis.
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Thinnes FP. Alzheimer disease controls cancer - concerning the apoptogenic interaction of cell membrane-standing type-1 VDAC and amyloid peptides via GxxxG motifs. Mol Genet Metab 2012; 106:502-3. [PMID: 22766436 DOI: 10.1016/j.ymgme.2012.06.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 06/05/2012] [Indexed: 01/30/2023]
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