1
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Is non-invasive brain stimulation effective for cognitive enhancement in Alzheimer's disease? An updated meta-analysis. Clin Neurophysiol 2022; 144:23-40. [PMID: 36215904 DOI: 10.1016/j.clinph.2022.09.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 08/30/2022] [Accepted: 09/18/2022] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Alzheimer's disease dementia (AD) and its preclinical stage, mild cognitive impairment (MCI), are critical issues confronting the aging society. Non-invasive brain stimulation (NIBS) techniques have the potential to be effective tools for enhancing cognitive functioning. The main objective of our meta-analysis was to quantify and update the status of the efficacy of repetitive Transcranial Magnetic Stimulation (rTMS) and Transcranial Direct Current Stimulation (tDCS) when applied in AD and MCI. METHODS The systematic literature search was conducted in PubMed and Web of Science according to PRISMA statement. RESULTS Pooled effect sizes (Hedges' g) from 32 studies were analyzed using random effect models. We found both, rTMS and tDCS to have significant immediate cognition-enhancing effect in AD with rTMS inducing also beneficial long-term effects. We found no evidence for synergistic effect of cognitive training with NIBS. CONCLUSIONS In AD a clinical recommendation can be made for NEURO-ADTM system and for high-frequency rTMS over the left dorsolateral prefrontal cortex (DLPFC) as probably effective protocols (B-level of evidence) and for anodal tDCS over the left DLPFC as a possibly effective. SIGNIFICANCE According to scientific literature, NIBS may be an effective method for improving cognition in AD and possibly in MCI.
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2
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Ammassari-Teule M. Inbred Mice Again at Stake: How the Cognitive Profile of the Wild-Type Mouse Background Discloses Pathogenic Effects of APP Mutations. Front Behav Neurosci 2022; 16:868473. [PMID: 35813596 PMCID: PMC9260142 DOI: 10.3389/fnbeh.2022.868473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
Increasing efforts have been made in the last decades to increase the face validity of Alzheimer's disease (AD) mouse models. Main advancements have consisted in generating AD mutations closer to those identified in humans, enhancing genetic diversity of wild-type backgrounds, and choosing protocols much apt to reveal AD-like cognitive dysfunctions. Nevertheless, two aspects remain less considered: the cognitive specialization of inbred strains used as recipient backgrounds of mutations and the heuristic importance of studying destabilization of memory circuits in pre-symptomatic mice facing cognitive challenges. This article underscores the relevance of these behavioral/experimental aspects by reviewing data which show that (i) inbred mice differ in their innate predisposition to rely on episodic vs. procedural memory, which implicates differential sensitivity to mutations aimed at disrupting temporal lobe-dependent memory, and that (ii) investigating training-driven neural alterations in asymptomatic mutants unveils early synaptic damage, which considerably anticipates detection of AD first signs.
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Affiliation(s)
- Martine Ammassari-Teule
- Laboratory of Psychobiology, Department of Experimental Neuroscience, Santa Lucia Foundation, Rome, Italy
- National Research Council, Institute of Biochemistry and Cell Biology, Rome, Italy
- *Correspondence: Martine Ammassari-Teule
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3
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Qu W, Yuan B, Liu J, Liu Q, Zhang X, Cui R, Yang W, Li B. Emerging role of AMPA receptor subunit GluA1 in synaptic plasticity: Implications for Alzheimer's disease. Cell Prolif 2020; 54:e12959. [PMID: 33188547 PMCID: PMC7791177 DOI: 10.1111/cpr.12959] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/23/2020] [Accepted: 10/24/2020] [Indexed: 02/06/2023] Open
Abstract
It is well established that GluA1 mediated synaptic plasticity plays a central role in the early development of AD. The complex cellular and molecular mechanisms that enable GluA1‐related synaptic regulation remain to fully understood. Particularly, understanding the mechanisms that disrupt GluA1 related synaptic plasticity is central to the development of disease‐modifying therapies which are sorely needed as the incidence of AD rises. We surmise that the published evidence establishes deficits in synaptic plasticity as a central factor of AD aetiology. We additionally highlight potential therapeutic strategies for the treatment of AD, and we delve into the roles of GluA1 in learning and memory. Particularly, we review the current understanding of the molecular interactions that confer the actions of this ubiquitous excitatory receptor subunit including post‐translational modification and accessory protein recruitment of the GluA1 subunit. These are proposed to regulate receptor trafficking, recycling, channel conductance and synaptic transmission and plasticity.
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Affiliation(s)
- Wenrui Qu
- Department of Hand Surgery, The Second Hospital of Jilin University, Changchun, China.,Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
| | - Baoming Yuan
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun, China
| | - Jun Liu
- Department of Hand Surgery, The Second Hospital of Jilin University, Changchun, China
| | - Qianqian Liu
- Department of Hand Surgery, The Second Hospital of Jilin University, Changchun, China
| | - Xi Zhang
- Department of Burn Surgery, The First Hospital of Jilin University, Changchun, China
| | - Ranji Cui
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
| | - Wei Yang
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
| | - Bingjin Li
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetic, The Second Hospital of Jilin University, Changchun, China
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4
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Ammassari-Teule M. Early-Occurring Dendritic Spines Alterations in Mouse Models of Alzheimer's Disease Inform on Primary Causes of Neurodegeneration. Front Synaptic Neurosci 2020; 12:566615. [PMID: 33013348 PMCID: PMC7511703 DOI: 10.3389/fnsyn.2020.566615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/17/2020] [Indexed: 01/04/2023] Open
Abstract
The consensus that synaptic failure is the earliest cause of cognitive deterioration in Alzheimer’s disease (AD) has initially led to investigate structural (dendritic spines) and physiological (LTP) synaptic dysfunctions in mouse models of AD with established cognitive alterations. The challenge is now to track down ultra-early alterations in spines to uncover causes rather than disease’s symptoms. This review article pinpoints dysregulations of the postsynaptic density (PSD) protein network which alter the morphology and function of spines in pre- and early- symptomatic hAPP mouse models of AD, and, hence, inform on primary causes of neurodegeneration.
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Affiliation(s)
- Martine Ammassari-Teule
- Institute of Biochemistry and Cell Biology, CNR-National Research Council, Rome, Italy.,Laboratory of Psychobiology, IRCCS Santa Lucia Foundation, Rome, Italy
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5
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Neural compensation in presymptomatic hAPP mouse models of Alzheimer's disease. ACTA ACUST UNITED AC 2020; 27:390-394. [PMID: 32817305 PMCID: PMC7433654 DOI: 10.1101/lm.050401.119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/26/2020] [Indexed: 11/25/2022]
Abstract
Largely inspired from clinical concepts like brain reserve, cognitive reserve, and neural compensation, here we review data showing how neural circuits reorganize in presymptomatic and early symptomatic hAPP mice to maintain memory intact. By informing on molecular alterations and compensatory adaptations which take place in the brain before mice show cognitive impairments, these data can help to identify ultra-early disease markers that could be targeted in a therapeutic perspective aimed at preventing rather than treating cognitive deterioration.
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6
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Huang TT, Leu D, Zou Y. Oxidative stress and redox regulation on hippocampal-dependent cognitive functions. Arch Biochem Biophys 2015; 576:2-7. [PMID: 25797440 DOI: 10.1016/j.abb.2015.03.014] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 03/12/2015] [Accepted: 03/13/2015] [Indexed: 12/17/2022]
Abstract
Hippocampal-dependent cognitive functions rely on production of new neurons and maintenance of dendritic structures to provide the synaptic plasticity needed for learning and formation of new memories. Hippocampal formation is exquisitely sensitive to patho-physiological changes, and reduced antioxidant capacity and exposure to low dose irradiation can significantly impede hippocampal-dependent functions of learning and memory by reducing the production of new neurons and alter dendritic structures in the hippocampus. Although the mechanism leading to impaired cognitive functions is complex, persistent oxidative stress likely plays an important role in the SOD-deficient and radiation-exposed hippocampal environment. Aging is associated with increased production of pro-oxidants and accumulation of oxidative end products. Similar to the hippocampal defects observed in SOD-deficient mice and mice exposed to low dose irradiation, reduced capacity in learning and memory, diminishing hippocampal neurogenesis, and altered dendritic network are universal in the aging brains. Given the similarities in cellular and structural changes in the aged, SOD-deficient, and radiation-exposed hippocampal environment and the corresponding changes in cognitive decline, understanding the shared underlying mechanism will provide more flexible and efficient use of SOD deficiency or irradiation to model age-related changes in cognitive functions and identify potential therapeutic or intervention methods.
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Affiliation(s)
- Ting-Ting Huang
- Geriatric Research, Education, and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, USA; Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.
| | - David Leu
- Geriatric Research, Education, and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, USA; Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Yani Zou
- Geriatric Research, Education, and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, USA; Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
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7
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Middei S, Ammassari-Teule M, Marie H. Synaptic plasticity under learning challenge. Neurobiol Learn Mem 2014; 115:108-15. [DOI: 10.1016/j.nlm.2014.08.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 08/01/2014] [Accepted: 08/06/2014] [Indexed: 10/24/2022]
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8
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Morelli E, Ghiglieri V, Pendolino V, Bagetta V, Pignataro A, Fejtova A, Costa C, Ammassari-Teule M, Gundelfinger ED, Picconi B, Calabresi P. Environmental enrichment restores CA1 hippocampal LTP and reduces severity of seizures in epileptic mice. Exp Neurol 2014; 261:320-7. [DOI: 10.1016/j.expneurol.2014.05.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 05/08/2014] [Indexed: 12/13/2022]
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9
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Alldred MJ, Lee SH, Petkova E, Ginsberg SD. Expression profile analysis of hippocampal CA1 pyramidal neurons in aged Ts65Dn mice, a model of Down syndrome (DS) and Alzheimer's disease (AD). Brain Struct Funct 2014; 220:2983-96. [PMID: 25031177 DOI: 10.1007/s00429-014-0839-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 07/02/2014] [Indexed: 11/29/2022]
Abstract
Down syndrome (DS) is caused by the triplication of human chromosome 21 (HSA21) and is the most common genetic cause of intellectual disability, with individuals having deficits in cognitive function including hippocampal learning and memory and neurodegeneration of cholinergic basal forebrain neurons, a pathological hallmark of Alzheimer's disease (AD). To date, the molecular underpinnings driving this pathology have not been elucidated. The Ts65Dn mouse is a segmental trisomy model of DS and like DS/AD pathology, displays age-related cognitive dysfunction and basal forebrain cholinergic neuron (BFCN) degeneration. To determine molecular and cellular changes important for elucidating mechanisms of neurodegeneration in DS/AD pathology, expression profiling studies were performed. Molecular fingerprinting of homogeneous populations of Cornu Ammonis 1 (CA1) pyramidal neurons was performed via laser capture microdissection followed by Terminal Continuation RNA amplification combined with custom-designed microarray analysis and subsequent validation of individual transcripts by qPCR and protein analysis via immunoblotting. Significant alterations were observed within CA1 pyramidal neurons of aged Ts65Dn mice compared to normal disomic (2N) littermates, notably in excitatory and inhibitory neurotransmission receptor families and neurotrophins, including brain-derived neurotrophic factor as well as several cognate neurotrophin receptors. Examining gene and protein expression levels after the onset of BFCN degeneration elucidated transcriptional and translational changes in neurons within a vulnerable circuit that may cause the AD-like pathology seen in DS as these individuals age, and provide rational targets for therapeutic interventions.
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Affiliation(s)
- Melissa J Alldred
- Center for Dementia Research, Nathan Kline Institute, 140 Old Orangeburg Road, Orangeburg, NY, 10962, USA
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10
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Cognitive Reserve and Alzheimer’s Disease. Mol Neurobiol 2014; 51:187-208. [DOI: 10.1007/s12035-014-8720-y] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Accepted: 04/17/2014] [Indexed: 12/13/2022]
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11
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Girard SD, Jacquet M, Baranger K, Migliorati M, Escoffier G, Bernard A, Khrestchatisky M, Féron F, Rivera S, Roman FS, Marchetti E. Onset of hippocampus-dependent memory impairments in 5XFAD transgenic mouse model of Alzheimer's disease. Hippocampus 2014; 24:762-72. [DOI: 10.1002/hipo.22267] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 02/17/2014] [Accepted: 02/25/2014] [Indexed: 12/15/2022]
Affiliation(s)
| | - Marlyse Jacquet
- Aix Marseille Université, CNRS, NICN, UMR7259; Marseille France
| | - Kévin Baranger
- Aix Marseille Université, CNRS, NICN, UMR7259; Marseille France
- APHM; CHU La Timone; Département de Neurologie et de Neuropsychologie; Marseille France
| | | | - Guy Escoffier
- Aix Marseille Université, CNRS, NICN, UMR7259; Marseille France
| | - Anne Bernard
- Aix Marseille Université, CNRS, NICN, UMR7259; Marseille France
| | | | - François Féron
- Aix Marseille Université, CNRS, NICN, UMR7259; Marseille France
| | - Santiago Rivera
- Aix Marseille Université, CNRS, NICN, UMR7259; Marseille France
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12
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Nisticò R, Mori F, Feligioni M, Nicoletti F, Centonze D. Synaptic plasticity in multiple sclerosis and in experimental autoimmune encephalomyelitis. Philos Trans R Soc Lond B Biol Sci 2013; 369:20130162. [PMID: 24298163 DOI: 10.1098/rstb.2013.0162] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Approximately half of all patients with multiple sclerosis (MS) experience cognitive dysfunction, including learning and memory impairment. Recent studies suggest that hippocampal pathology is involved, although the mechanisms underlying these deficits remain poorly understood. Evidence obtained from a mouse model of MS, the experimental autoimmune encephalomyelitis (EAE), suggests that in the hippocampus of EAE mice long-term potentiation (LTP) is favoured over long-term depression in response to repetitive synaptic activation, through a mechanism dependent on enhanced IL-1β released from infiltrating lymphocytes or activated microglia. Facilitated LTP during an immune-mediated attack might underlie functional recovery, but also cognitive deficits and excitotoxic neurodegeneration. Having identified that pro-inflammatory cytokines such as IL-1β can influence synaptic function and integrity in early MS, it is hoped that new treatments targeted towards preventing synaptic pathology can be developed.
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Affiliation(s)
- Robert Nisticò
- Department of Physiology and Pharmacology, Sapienza University of Rome, , 00185 Rome, Italy
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13
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Tiveron C, Fasulo L, Capsoni S, Malerba F, Marinelli S, Paoletti F, Piccinin S, Scardigli R, Amato G, Brandi R, Capelli P, D'Aguanno S, Florenzano F, La Regina F, Lecci A, Manca A, Meli G, Pistillo L, Berretta N, Nisticò R, Pavone F, Cattaneo A. ProNGF\NGF imbalance triggers learning and memory deficits, neurodegeneration and spontaneous epileptic-like discharges in transgenic mice. Cell Death Differ 2013; 20:1017-30. [PMID: 23538417 DOI: 10.1038/cdd.2013.22] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 02/14/2013] [Accepted: 02/18/2013] [Indexed: 01/19/2023] Open
Abstract
ProNGF, the precursor of mature nerve growth factor (NGF), is the most abundant form of NGF in the brain. ProNGF and mature NGF differ significantly in their receptor interaction properties and in their bioactivity. ProNGF increases markedly in the cortex of Alzheimer's disease (AD) brains and proNGF\NGF imbalance has been postulated to play a role in neurodegeneration. However, a direct proof for a causal link between increased proNGF and AD neurodegeneration is lacking. In order to evaluate the consequences of increased levels of proNGF in the postnatal brain, transgenic mice expressing a furin cleavage-resistant form of proNGF, under the control of the neuron-specific mouse Thy1.2 promoter, were derived and characterized. Different transgenic lines displayed a phenotypic gradient of neurodegenerative severity features. We focused the analysis on the two lines TgproNGF#3 and TgproNGF#72, which shared learning and memory impairments in behavioral tests, cholinergic deficit and increased Aβ-peptide immunoreactivity. In addition, TgproNGF#3 mice developed Aβ oligomer immunoreactivity, as well as late diffuse astrocytosis. Both TgproNGF lines also display electrophysiological alterations related to spontaneous epileptic-like events. The results provide direct evidence that alterations in the proNGF/NGF balance in the adult brain can be an upstream driver of neurodegeneration, contributing to a circular loop linking alterations of proNGF/NGF equilibrium to excitatory/inhibitory synaptic imbalance and amyloid precursor protein (APP) dysmetabolism.
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Affiliation(s)
- C Tiveron
- Neurotrophic Factors and Neurodegenerative Diseases Unit, EBRI-European Brain Research Institute, Rome, Italy
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14
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Corniola R, Zou Y, Leu D, Fike JR, Huang TT. Paradoxical relationship between Mn superoxide dismutase deficiency and radiation-induced cognitive defects. PLoS One 2012; 7:e49367. [PMID: 23145165 PMCID: PMC3493523 DOI: 10.1371/journal.pone.0049367] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 10/10/2012] [Indexed: 02/04/2023] Open
Abstract
Radiation therapy of the CNS, even at low doses, can lead to deficits in neurocognitive functions. Reduction in hippocampal neurogenesis is usually, but not always, associated with cognitive deficits resulting from radiation therapy. Generation of reactive oxygen species is considered the main cause of radiation-induced tissue injuries, and elevated levels of oxidative stress persist long after the initial cranial irradiation. Consequently, mutant mice with reduced levels of the mitochondrial antioxidant enzyme, Mn superoxide dismutase (MnSOD or Sod2), are expected to be more sensitive to radiation-induced changes in hippocampal neurogenesis and the related functions. In this study, we showed that MnSOD deficiency led to reduced generation of immature neurons in Sod2−/+ mice even though progenitor cell proliferation was not affected. Compared to irradiated Sod2+/+ mice, which showed cognitive defects and reduced differentiation of newborn cells towards the neuronal lineage, irradiated Sod2−/+ mice showed normal hippocampal-dependent cognitive functions and normal differentiation pattern for newborn neurons and astroglia. However, we also observed a disproportional decrease in newborn neurons in irradiated Sod2−/+ following behavioral studies, suggesting that MnSOD deficiency may render newborn neurons more sensitive to stress from behavioral trainings following cranial irradiation. A positive correlation between normal cognitive functions and normal dendritic spine densities in dentate granule cells was observed. The data suggest that maintenance of synaptic connections, via maintenance of dendritic spines, may be important for normal cognitive functions following cranial irradiation.
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Affiliation(s)
- Rikki Corniola
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, United States of America
| | - Yani Zou
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, United States of America
| | - David Leu
- Palo Alto Institute for Research and Education, Palo Alto, California, United States of America
- Geriatric Research, Education, and Clinical Center (GRECC), VA Palo Alto Health Care System, Palo Alto, California, United States of America
| | - John R. Fike
- Departments of Neurosurgery and Radiation Oncology, University of California San Francisco, San Francisco, California, United States of America
| | - Ting-Ting Huang
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, United States of America
- Geriatric Research, Education, and Clinical Center (GRECC), VA Palo Alto Health Care System, Palo Alto, California, United States of America
- * E-mail:
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15
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Nisticò R, Pignatelli M, Piccinin S, Mercuri NB, Collingridge G. Targeting synaptic dysfunction in Alzheimer's disease therapy. Mol Neurobiol 2012; 46:572-87. [PMID: 22914888 DOI: 10.1007/s12035-012-8324-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 08/06/2012] [Indexed: 12/22/2022]
Abstract
In the past years, major efforts have been made to understand the genetics and molecular pathogenesis of Alzheimer's disease (AD), which has been translated into extensive experimental approaches aimed at slowing down or halting disease progression. Advances in transgenic (Tg) technologies allowed the engineering of different mouse models of AD recapitulating a range of AD-like features. These Tg models provided excellent opportunities to analyze the bases for the temporal evolution of the disease. Several lines of evidence point to synaptic dysfunction as a cause of AD and that synapse loss is a pathological correlate associated with cognitive decline. Therefore, the phenotypic characterization of these animals has included electrophysiological studies to analyze hippocampal synaptic transmission and long-term potentiation, a widely recognized cellular model for learning and memory. Transgenic mice, along with non-Tg models derived mainly from exogenous application of Aβ, have also been useful experimental tools to test the various therapeutic approaches. As a result, numerous pharmacological interventions have been reported to attenuate synaptic dysfunction and improve behavior in the different AD models. To date, however, very few of these findings have resulted in target validation or successful translation into disease-modifying compounds in humans. Here, we will briefly review the synaptic alterations across the different animal models and we will recapitulate the pharmacological strategies aimed at rescuing hippocampal plasticity phenotypes. Finally, we will highlight intrinsic limitations in the use of experimental systems and related challenges in translating preclinical studies into human clinical trials.
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Affiliation(s)
- Robert Nisticò
- Department of Pharmacobiology, University of Calabria, 87036 Rende, Italy.
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16
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Postsynaptic dysfunction is associated with spatial and object recognition memory loss in a natural model of Alzheimer's disease. Proc Natl Acad Sci U S A 2012; 109:13835-40. [PMID: 22869717 DOI: 10.1073/pnas.1201209109] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Alzheimer's disease (AD) is an age-related neurodegenerative disorder associated with progressive memory loss, severe dementia, and hallmark neuropathological markers, such as deposition of amyloid-β (Aβ) peptides in senile plaques and accumulation of hyperphosphorylated tau proteins in neurofibrillary tangles. Recent evidence obtained from transgenic mouse models suggests that soluble, nonfibrillar Aβ oligomers may induce synaptic failure early in AD. Despite their undoubted value, these transgenic models rely on genetic manipulations that represent the inherited and familial, but not the most abundant, sporadic form of AD. A nontransgenic animal model that still develops hallmarks of AD would be an important step toward understanding how sporadic AD is initiated. Here we show that starting between 12 and 36 mo of age, the rodent Octodon degus naturally develops neuropathological signs of AD, such as accumulation of Aβ oligomers and phosphorylated tau proteins. Moreover, age-related changes in Aβ oligomers and tau phosphorylation levels are correlated with decreases in spatial and object recognition memory, postsynaptic function, and synaptic plasticity. These findings validate O. degus as a suitable natural model for studying how sporadic AD may be initiated.
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17
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Vetere G, Restivo L, Ammassari-Teule M. Pre-synaptic control of remote fear extinction in the neocortex. Front Behav Neurosci 2012; 6:34. [PMID: 22737111 PMCID: PMC3380197 DOI: 10.3389/fnbeh.2012.00034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 06/08/2012] [Indexed: 12/26/2022] Open
Abstract
Consolidation of remote memory enhances immediate early genes induction (IEGs), augments the expression of the pre-synaptic growth associated protein-43 (GAP-43), and increases the density and size of dendritic spines in anterior cingulate (aCC) and infra-limbic (ILC) cortices. Remote memory extinction, however, does not uniformly alter consolidation-induced structural changes. In the aCC, the density, but not the size, of spines is reset to pseudo-conditioning levels while novel thin spines are formed in the ILC. Whether IEGs and GAP-43 also undergo region-specific changes upon remote memory extinction is undetermined. Here we confirm in the same batch of mice that c-Fos induction and GAP-43 expression are increased in both the aCC and the ILC 36 days after contextual fear conditioning. We then show that, in both regions, remote memory extinction is associated with decrease of c-Fos induction but no change in GAP-43 expression thus revealing similar, although protein-specific, pre-synaptic adaptations in aCC and ILC neurons. These observations, in addition to our previous report of region-specific post-synaptic structural changes, disclose a complex pattern of extinction-driven neocortical alterations suitable to support erasure or reinstatement of fear according to the environment demand.
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Affiliation(s)
- Gisella Vetere
- CNR-National Research Council of Italy, Cell Biology and Neurobiology Institute Rome, Italy
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18
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Pignatelli M, Vollmayr B, Richter SH, Middei S, Matrisciano F, Molinaro G, Nasca C, Battaglia G, Ammassari-Teule M, Feligioni M, Nisticò R, Nicoletti F, Gass P. Enhanced mGlu5-receptor dependent long-term depression at the Schaffer collateral-CA1 synapse of congenitally learned helpless rats. Neuropharmacology 2012; 66:339-47. [PMID: 22709946 DOI: 10.1016/j.neuropharm.2012.05.046] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 05/19/2012] [Accepted: 05/31/2012] [Indexed: 12/31/2022]
Abstract
Alterations of the glutamatergic system have been implicated in the pathophysiology and treatment of major depression. In order to investigate the expression and function of mGlu5 receptors in an animal model for treatment-resistant depression we used rats bred for congenital learned helplessness (cLH) and the control strain, bred for resistance against inescapable stress, congenitally. not learned helpless rats (cNLH). Western blot analysis showed an increased expression of mGlu5 (but not mGlu1a) receptors in the hippocampus of cLH rats, as compared with control cNLH rats. We also examined mGlu1/5 receptor signaling by in vivo measurement of DHPG-stimulated polyphosphoinositides hydrolysis. Stimulation of (3)H-inositolmonophosphate formation induced by i.c.v. injection of DHPG was enhanced by about 50% in the hippocampus of cLH rats. Correspondingly, DHPG-induced long-term depression (LTD) at Schaffer collateral/CA1 pyramidal cell synapses was amplified in hippocampal slices of cLH rats, whereas LTD induced by low frequency stimulation of the Schaffer collaterals did not change. Moreover, these effects were associated with decreased basal dendritic spine density of CA1 pyramidal cell in cLH rats. These data raise the attractive possibility that changes in the expression and function of mGlu5 receptors in the hippocampus might underlie the changes in synaptic plasticity associated with the depressive-like phenotype of cLH rats. However, chronic treatment of cLH rats with MPEP did not reverse learned helplessness, indicating that the enhanced mGlu5 receptor function is not the only player in the behavioral phenotype of this genetic model of depression. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Marco Pignatelli
- Department of Physiology and Pharmacology, University of Rome "La Sapienza", 00185 Rome, Italy.
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Chronic treatment with rivastigmine in patients with Alzheimer’s disease: A study on primary motor cortex excitability tested by 5Hz-repetitive transcranial magnetic stimulation. Clin Neurophysiol 2012; 123:902-9. [DOI: 10.1016/j.clinph.2011.09.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 09/01/2011] [Accepted: 09/05/2011] [Indexed: 12/27/2022]
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Hu NW, Ondrejcak T, Rowan MJ. Glutamate receptors in preclinical research on Alzheimer's disease: Update on recent advances. Pharmacol Biochem Behav 2012; 100:855-62. [DOI: 10.1016/j.pbb.2011.04.013] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 04/05/2011] [Accepted: 04/15/2011] [Indexed: 01/01/2023]
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Hansen N. Action mechanisms of transcranial direct current stimulation in Alzheimer's disease and memory loss. Front Psychiatry 2012; 3:48. [PMID: 22615703 PMCID: PMC3351674 DOI: 10.3389/fpsyt.2012.00048] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 04/24/2012] [Indexed: 01/01/2023] Open
Abstract
The pharmacological treatment of Alzheimer's disease (AD) is often limited and accompanied by drug side effects. Thus alternative therapeutic strategies such as non-invasive brain stimulation are needed. Few studies have demonstrated that transcranial direct current stimulation (tDCS), a method of neuromodulation with consecutive robust excitability changes within the stimulated cortex area, is beneficial in AD. There is also evidence that tDCS enhances memory function in cognitive rehabilitation in depressive patients, Parkinson's disease, and stroke. tDCS improves working and visual recognition memory in humans and object-recognition learning in the elderly. AD's neurobiological mechanisms comprise changes in neuronal activity and the cerebral blood flow (CBF) caused by altered microvasculature, synaptic dysregulation from ß-amyloid peptide accumulation, altered neuromodulation via degenerated modulatory amine transmitter systems, altered brain oscillations, and changes in network connectivity. tDCS alters (i) neuronal activity and (ii) human CBF, (iii) has synaptic and non-synaptic after-effects (iv), can modify neurotransmitters polarity-dependently, (v) and alter oscillatory brain activity and (vi) functional connectivity patterns in the brain. It thus is reasonable to use tDCS as a therapeutic instrument in AD as it improves cognitive function in manner based on a disease mechanism. Moreover, it could prove valuable in other types of dementia. Future large-scale clinical and mechanism-oriented studies may enable us to identify its therapeutic validity in other types of demential disorders.
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Affiliation(s)
- Niels Hansen
- Department of Neurophysiology, Ruhr University Bochum Bochum, Germany
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Spines, plasticity, and cognition in Alzheimer's model mice. Neural Plast 2011; 2012:319836. [PMID: 22203915 PMCID: PMC3238410 DOI: 10.1155/2012/319836] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 10/27/2011] [Indexed: 01/03/2023] Open
Abstract
The pathological hallmarks of Alzheimer's disease (AD)--widespread synaptic and neuronal loss and the pathological accumulation of amyloid-beta peptide (Aβ) in senile plaques, as well as hyperphosphorylated tau in neurofibrillary tangles--have been known for many decades, but the links between AD pathology and dementia and effective therapeutic strategies remain elusive. Transgenic mice have been developed based on rare familial forms of AD and frontotemporal dementia, allowing investigators to test in detail the structural, functional, and behavioral consequences of AD-associated pathology. Here, we review work on transgenic AD models that investigate the degeneration of dendritic spine structure, synaptic function, and cognition. Together, these data support a model of AD pathogenesis in which soluble Aβ initiates synaptic dysfunction and loss, as well as pathological changes in tau, which contribute to both synaptic and neuronal loss. These changes in synapse structure and function as well as frank synapse and neuronal loss contribute to the neural system dysfunction which causes cognitive deficits. Understanding the underpinnings of dementia in AD will be essential to develop and evaluate therapeutic approaches for this widespread and devastating disease.
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Liu HL, Zhao G, Cai K, Zhao HH, Shi LD. Treadmill exercise prevents decline in spatial learning and memory in APP/PS1 transgenic mice through improvement of hippocampal long-term potentiation. Behav Brain Res 2011; 218:308-14. [DOI: 10.1016/j.bbr.2010.12.030] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 12/16/2010] [Accepted: 12/17/2010] [Indexed: 01/12/2023]
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Hippocampal synaptic plasticity in Alzheimer’s disease: what have we learned so far from transgenic models? Rev Neurosci 2011; 22:373-402. [DOI: 10.1515/rns.2011.035] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Fitzjohn SM, Kuenzi F, Morton RA, Rosahl TW, Lewis H, Smith D, Seabrook GR, Collingridge GL. A study of long-term potentiation in transgenic mice over-expressing mutant forms of both amyloid precursor protein and presenilin-1. Mol Brain 2010; 3:21. [PMID: 20630068 PMCID: PMC2912307 DOI: 10.1186/1756-6606-3-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Accepted: 07/14/2010] [Indexed: 12/31/2022] Open
Abstract
Synaptic transmission and long-term potentiation (LTP) in the CA1 region of hippocampal slices have been studied during ageing of a double transgenic mouse strain relevant to early-onset familial Alzheimer's disease (AD). This strain, which over-expresses both the 695 amino acid isoform of human amyloid precursor protein (APP) with K670N and M671L mutations and presenilin 1 with the A246E mutation, has accelerated amyloidosis and plaque formation. There was a decrease in synaptic transmission in both wildtype and transgenic mice between 2 and 9 months of age. However, preparing slices from 14 month old animals in kynurenic acid (1 mM) counteracted this age-related deficit. Basal transmission and paired-pulse facilitation was similar between the two groups at all ages (2, 6, 9 and 14 months) tested. Similarly, at all ages LTP, induced either by theta burst stimulation or by multiple tetani, was normal. These data show that a prolonged, substantially elevated level of Abeta are not sufficient to cause deficits in the induction or expression of LTP in the CA1 hippocampal region.
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Affiliation(s)
- Stephen M Fitzjohn
- MRC Centre for Synaptic Plasticity, Department of Anatomy, University of Bristol, UK.
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