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Buchanan RA, Wang Y, May JM, Harrison FE. Ascorbate insufficiency disrupts glutamatergic signaling and alters electroencephalogram phenotypes in a mouse model of Alzheimer's disease. Neurobiol Dis 2024; 199:106602. [PMID: 39004234 DOI: 10.1016/j.nbd.2024.106602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 07/08/2024] [Accepted: 07/09/2024] [Indexed: 07/16/2024] Open
Abstract
Clinical studies have reported that increased epileptiform and subclinical epileptiform activity can be detected in many patients with an Alzheimer's disease (AD) diagnosis using electroencephalogram (EEG) and this may correlate with poorer cognition. Ascorbate may have a specific role as a neuromodulator in AD as it is released concomitantly with glutamate reuptake following excitatory neurotransmission. Insufficiency may therefore result in an exacerbated excitatory/inhibitory imbalance in neuronal signaling. Using a mouse model of AD that requires dietary ascorbate (Gulo-/-APPswe/PSEN1dE9), EEG was recorded at baseline and during 4 weeks of ascorbate depletion in young (5-month-old) and aged (20-month-old) animals. Data were scored for changes in quantity of spike trains, individual spikes, sleep-wake rhythms, sleep fragmentation, and brainwave power bands during light periods each week. We found an early increase in neuronal spike discharges with age and following ascorbate depletion in AD model mice and not controls, which did not correlate with brain amyloid load. Our data also show more sleep fragmentation with age and with ascorbate depletion. Additionally, changes in brain wave activity were observed within different vigilance states in both young and aged mice, where Gulo-/-APPswe/PSEN1dE9 mice had shifts towards higher frequency bands (alpha, beta, and gamma) and ascorbate depletion resulted in shifts towards lower frequency bands (delta and theta). Microarray data supported ascorbate insufficiency altering glutamatergic transmission through the decreased expression of glutamate related genes, however no changes in protein expression of glutamate reuptake transporters were observed. These data suggest that maintaining optimal brain ascorbate levels may support normal brain electrical activity and sleep patterns, particularly in AD patient populations where disruptions are observed.
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Affiliation(s)
- Rebecca A Buchanan
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States
| | - Yuhan Wang
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - James M May
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Fiona E Harrison
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States.
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Chartampila E, Elayouby KS, Leary P, LaFrancois JJ, Alcantara-Gonzalez D, Jain S, Gerencer K, Botterill JJ, Ginsberg SD, Scharfman HE. Choline supplementation in early life improves and low levels of choline can impair outcomes in a mouse model of Alzheimer's disease. eLife 2024; 12:RP89889. [PMID: 38904658 PMCID: PMC11192536 DOI: 10.7554/elife.89889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2024] Open
Abstract
Maternal choline supplementation (MCS) improves cognition in Alzheimer's disease (AD) models. However, the effects of MCS on neuronal hyperexcitability in AD are unknown. We investigated the effects of MCS in a well-established mouse model of AD with hyperexcitability, the Tg2576 mouse. The most common type of hyperexcitability in Tg2576 mice are generalized EEG spikes (interictal spikes [IIS]). IIS also are common in other mouse models and occur in AD patients. In mouse models, hyperexcitability is also reflected by elevated expression of the transcription factor ∆FosB in the granule cells (GCs) of the dentate gyrus (DG), which are the principal cell type. Therefore, we studied ΔFosB expression in GCs. We also studied the neuronal marker NeuN within hilar neurons of the DG because reduced NeuN protein expression is a sign of oxidative stress or other pathology. This is potentially important because hilar neurons regulate GC excitability. Tg2576 breeding pairs received a diet with a relatively low, intermediate, or high concentration of choline. After weaning, all mice received the intermediate diet. In offspring of mice fed the high choline diet, IIS frequency declined, GC ∆FosB expression was reduced, and hilar NeuN expression was restored. Using the novel object location task, spatial memory improved. In contrast, offspring exposed to the relatively low choline diet had several adverse effects, such as increased mortality. They had the weakest hilar NeuN immunoreactivity and greatest GC ΔFosB protein expression. However, their IIS frequency was low, which was surprising. The results provide new evidence that a diet high in choline in early life can improve outcomes in a mouse model of AD, and relatively low choline can have mixed effects. This is the first study showing that dietary choline can regulate hyperexcitability, hilar neurons, ΔFosB, and spatial memory in an animal model of AD.
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Affiliation(s)
- Elissavet Chartampila
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric ResearchOrangeburgUnited States
| | - Karim S Elayouby
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric ResearchOrangeburgUnited States
| | - Paige Leary
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric ResearchOrangeburgUnited States
- Department of Neuroscience and Physiology, New York University Grossman School of MedicineNew YorkUnited States
| | - John J LaFrancois
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric ResearchOrangeburgUnited States
- Departments of Child and Adolescent Psychiatry, New York University Grossman School of MedicineNew YorkUnited States
| | - David Alcantara-Gonzalez
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric ResearchOrangeburgUnited States
- Departments of Child and Adolescent Psychiatry, New York University Grossman School of MedicineNew YorkUnited States
| | - Swati Jain
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric ResearchOrangeburgUnited States
| | - Kasey Gerencer
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric ResearchOrangeburgUnited States
| | - Justin J Botterill
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric ResearchOrangeburgUnited States
| | - Stephen D Ginsberg
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric ResearchOrangeburgUnited States
- Department of Neuroscience and Physiology, New York University Grossman School of MedicineNew YorkUnited States
- Department of Psychiatry, New York University Grossman School of MedicineNew YorkUnited States
- NYU Neuroscience Institute, New York University Grossman School of MedicineNew YorkUnited States
| | - Helen E Scharfman
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric ResearchOrangeburgUnited States
- Department of Neuroscience and Physiology, New York University Grossman School of MedicineNew YorkUnited States
- Departments of Child and Adolescent Psychiatry, New York University Grossman School of MedicineNew YorkUnited States
- Department of Psychiatry, New York University Grossman School of MedicineNew YorkUnited States
- NYU Neuroscience Institute, New York University Grossman School of MedicineNew YorkUnited States
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Nietz AK, Popa LS, Carter RE, Gerhart ML, Manikonda K, Ranum LP, Ebner TJ. Cerebral cortical functional hyperconnectivity in a mouse model of spinocerebellar ataxia type 8 (SCA8). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.20.599947. [PMID: 38948725 PMCID: PMC11212952 DOI: 10.1101/2024.06.20.599947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Spinocerebellar Ataxia Type 8 (SCA8) is an inherited neurodegenerative disease caused by a bidirectionally expressed CTG●CAG expansion mutation in the ATXN-8 and ATXN8-OS genes. While primarily a motor disorder, psychiatric and cognitive symptoms have been reported. It is difficult to elucidate how the disease alters brain function in areas with little or no degeneration producing both motor and cognitive symptoms. Using transparent polymer skulls and CNS-wide GCaMP6f expression, we studied neocortical networks throughout SCA8 progression using wide-field Ca2+ imaging in a transgenic mouse model of SCA8. We observed that neocortical networks in SCA8+ mice were hyperconnected globally which led to network configurations with increased global efficiency and centrality. At the regional level, significant network changes occurred in nearly all cortical regions, however mainly involved sensory and association cortices. Changes in functional connectivity in anterior motor regions worsened later in the disease. Near perfect decoding of animal genotype was obtained using a generalized linear model based on canonical correlation strengths between activity in cortical regions. The major contributors to decoding were concentrated in the somatosensory, higher visual and retrosplenial cortices and occasionally extended into the motor regions, demonstrating that the areas with the largest network changes are predictive of disease state.
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Affiliation(s)
- Angela K. Nietz
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Laurentiu S. Popa
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Russell E. Carter
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Morgan L Gerhart
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Keerthi Manikonda
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Laura P.W. Ranum
- Department of Molecular Genetics & Microbiology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Timothy J. Ebner
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
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Moguilner SG, Berezuk C, Bender AC, Pellerin KR, Gomperts SN, Cash SS, Sarkis RA, Lam AD. Sleep functional connectivity, hyperexcitability, and cognition in Alzheimer's disease. Alzheimers Dement 2024; 20:4234-4249. [PMID: 38764252 PMCID: PMC11180941 DOI: 10.1002/alz.13861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/29/2024] [Accepted: 04/01/2024] [Indexed: 05/21/2024]
Abstract
INTRODUCTION Sleep disturbances are common in Alzheimer's disease (AD) and may reflect pathologic changes in brain networks. To date, no studies have examined changes in sleep functional connectivity (FC) in AD or their relationship with network hyperexcitability and cognition. METHODS We assessed electroencephalogram (EEG) sleep FC in 33 healthy controls, 36 individuals with AD without epilepsy, and 14 individuals with AD and epilepsy. RESULTS AD participants showed increased gamma connectivity in stage 2 sleep (N2), which was associated with longitudinal cognitive decline. Network hyperexcitability in AD was associated with a distinct sleep connectivity signature, characterized by decreased N2 delta connectivity and reversal of several connectivity changes associated with AD. Machine learning algorithms using sleep connectivity features accurately distinguished diagnostic groups and identified "fast cognitive decliners" among study participants who had AD. DISCUSSION Our findings reveal changes in sleep functional networks associated with cognitive decline in AD and may have implications for disease monitoring and therapeutic development. HIGHLIGHTS Brain functional connectivity (FC) in Alzheimer's disease is altered during sleep. Sleep FC measures correlate with cognitive decline in AD. Network hyperexcitability in AD has a distinct sleep connectivity signature.
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Affiliation(s)
- Sebastian G. Moguilner
- Department of NeurologyHarvard Medical SchoolBostonMassachusettsUSA
- Department of NeurologyMassachusetts General HospitalBostonMassachusettsUSA
| | - Courtney Berezuk
- Department of NeurologyHarvard Medical SchoolBostonMassachusettsUSA
- Department of NeurologyMassachusetts General HospitalBostonMassachusettsUSA
| | - Alex C. Bender
- Department of NeurologyHarvard Medical SchoolBostonMassachusettsUSA
- Department of NeurologyMassachusetts General HospitalBostonMassachusettsUSA
| | - Kyle R. Pellerin
- Department of NeurologyMassachusetts General HospitalBostonMassachusettsUSA
| | - Stephen N. Gomperts
- Department of NeurologyHarvard Medical SchoolBostonMassachusettsUSA
- Department of NeurologyMassachusetts General HospitalBostonMassachusettsUSA
| | - Sydney S. Cash
- Department of NeurologyHarvard Medical SchoolBostonMassachusettsUSA
- Department of NeurologyMassachusetts General HospitalBostonMassachusettsUSA
| | - Rani A. Sarkis
- Department of NeurologyHarvard Medical SchoolBostonMassachusettsUSA
- Department of NeurologyBrigham and Women's HospitalBostonMassachusettsUSA
| | - Alice D. Lam
- Department of NeurologyHarvard Medical SchoolBostonMassachusettsUSA
- Department of NeurologyMassachusetts General HospitalBostonMassachusettsUSA
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Chartampila E, Elayouby KS, Leary P, LaFrancois JJ, Alcantara-Gonzalez D, Jain S, Gerencer K, Botterill JJ, Ginsberg SD, Scharfman HE. Choline supplementation in early life improves and low levels of choline can impair outcomes in a mouse model of Alzheimer's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.12.540428. [PMID: 37214805 PMCID: PMC10197642 DOI: 10.1101/2023.05.12.540428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Maternal choline supplementation (MCS) improves cognition in Alzheimer's disease (AD) models. However, effects of MCS on neuronal hyperexcitability in AD are unknown. We investigated effects of MCS in a well-established mouse model of AD with hyperexcitability, the Tg2576 mouse. The most common type of hyperexcitability in Tg2576 mice are generalized EEG spikes (interictal spikes; IIS). IIS also are common in other mouse models and occur in AD patients. Im mouse models, hyperexcitability is also reflected by elevated expression of the transcription factor ΔFosB in the granule cells (GCs) of the dentate gyrus (DG), which are the principal cell type. Therefore we studied ΔFosB expression in GCs. We also studied the the neuronal marker NeuN within hilar neurons of the DG because other studies have reduced NeuN protein expression is a sign of oxidative stress or other pathology. This is potentially important because hilar neurons regulate GC excitability. Tg2576 breeding pairs received a diet with a relatively low, intermediate or high concentration of choline. After weaning, all mice received the intermediate diet. In offspring of mice fed the high choline diet, IIS frequency declined, GC ΔFosB expression was reduced, and NeuN expression was restored. Using the novel object location task, spatial memory improved. In contrast, offspring exposed to the relatively low choline diet had several adverse effects, such as increased mortality. They had the weakest hilar NeuN immunoreactivity and greatest GC ΔFosB protein expression. However, their IIS frequency was low, which was surprising. The results provide new evidence that a diet high in choline in early life can improve outcomes in a mouse model of AD, and relatively low choline can have mixed effects. This is the first study showing that dietary choline can regulate hyperexcitability, hilar neurons, ΔFosB and spatial memory in an animal model of AD.
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Affiliation(s)
- Elissavet Chartampila
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Current address:Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27510
| | - Karim S. Elayouby
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Current address: Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029
| | - Paige Leary
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, NY 100016
| | - John J. LaFrancois
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Department of Child and Adolescent Psychiatry , New York University Grossman School of Medicine, New York, NY 10016
| | - David Alcantara-Gonzalez
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Department of Child and Adolescent Psychiatry , New York University Grossman School of Medicine, New York, NY 10016
| | - Swati Jain
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
| | - Kasey Gerencer
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Current address: Department of Psychology, University of Maine, Orono, ME 04469
| | - Justin J. Botterill
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Current address: Department of Anatomy, Physiology, & Pharmacology, College of Medicine, Saskatoon, SK S7N 5E5
| | - Stephen D. Ginsberg
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, NY 100016
- Department of Psychiatry, New York University Grossman School of Medicine New York, NY 10016
- NYU Neuroscience Institute,, New York University Grossman School of Medicine, New York, NY 10016
| | - Helen E. Scharfman
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, NY 100016
- Department of Child and Adolescent Psychiatry , New York University Grossman School of Medicine, New York, NY 10016
- Department of Psychiatry, New York University Grossman School of Medicine New York, NY 10016
- NYU Neuroscience Institute,, New York University Grossman School of Medicine, New York, NY 10016
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B Szabo A, Sayegh F, Gauzin S, Lejards C, Guiard B, Valton L, Verret L, Rampon C, Dahan L. No major effect of dopamine receptor 1/5 antagonist SCH-23390 on epileptic activity in the Tg2576 mouse model of amyloidosis. Eur J Neurosci 2024; 59:1558-1566. [PMID: 38308520 DOI: 10.1111/ejn.16268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 12/19/2023] [Accepted: 01/14/2024] [Indexed: 02/04/2024]
Abstract
The excitation-inhibition imbalance manifesting as epileptic activities in Alzheimer's disease is gaining more and more attention, and several potentially involved cellular and molecular pathways are currently under investigation. Based on in vitro studies, dopamine D1-type receptors in the anterior cingulate cortex and the hippocampus have been proposed to participate in this peculiar co-morbidity in mouse models of amyloidosis. Here, we tested the implication of dopaminergic transmission in vivo in the Tg2576 mouse model of Alzheimer's disease by monitoring epileptic activities via intracranial EEG before and after treatment with dopamine antagonists. Our results show that neither the D1-like dopamine receptor antagonist SCH23390 nor the D2-like dopamine receptor antagonist haloperidol reduces the frequency of epileptic activities. While requiring further investigation, our results indicate that on a systemic level, dopamine receptors are not significantly contributing to epilepsy observed in vivo in this mouse model of Alzheimer's disease.
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Affiliation(s)
- Anna B Szabo
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
- Centre de recherche Cerveau et Cognition (CerCo), CNRS, UMR 5549, Toulouse Mind and Brain Institute (TMBI), University of Toulouse, University Paul Sabatier (UPS), Toulouse, France
| | - Farès Sayegh
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Sèbastien Gauzin
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Camille Lejards
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Bruno Guiard
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Luc Valton
- Centre de recherche Cerveau et Cognition (CerCo), CNRS, UMR 5549, Toulouse Mind and Brain Institute (TMBI), University of Toulouse, University Paul Sabatier (UPS), Toulouse, France
- Department of Neurology, Hôpital Pierre Paul Riquet - Purpan, Toulouse University Hospital, University of Toulouse, Toulouse, France
| | - Laure Verret
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Claire Rampon
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Lionel Dahan
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
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Slutsky I. Linking activity dyshomeostasis and sleep disturbances in Alzheimer disease. Nat Rev Neurosci 2024; 25:272-284. [PMID: 38374463 DOI: 10.1038/s41583-024-00797-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2024] [Indexed: 02/21/2024]
Abstract
The presymptomatic phase of Alzheimer disease (AD) starts with the deposition of amyloid-β in the cortex and begins a decade or more before the emergence of cognitive decline. The trajectory towards dementia and neurodegeneration is shaped by the pathological load and the resilience of neural circuits to the effects of this pathology. In this Perspective, I focus on recent advances that have uncovered the vulnerability of neural circuits at early stages of AD to hyperexcitability, particularly when the brain is in a low-arousal states (such as sleep and anaesthesia). Notably, this hyperexcitability manifests before overt symptoms such as sleep and memory deficits. Using the principles of control theory, I analyse the bidirectional relationship between homeostasis of neuronal activity and sleep and propose that impaired activity homeostasis during sleep leads to hyperexcitability and subsequent sleep disturbances, whereas sleep disturbances mitigate hyperexcitability via negative feedback. Understanding the interplay among activity homeostasis, neuronal excitability and sleep is crucial for elucidating the mechanisms of vulnerability to and resilience against AD pathology and for identifying new therapeutic avenues.
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Affiliation(s)
- Inna Slutsky
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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Criscuolo C, Chartampila E, Ginsberg SD, Scharfman HE. Dentate Gyrus Granule Cells Show Stability of BDNF Protein Expression in Mossy Fiber Axons with Age, and Resistance to Alzheimer's Disease Neuropathology in a Mouse Model. eNeuro 2024; 11:ENEURO.0192-23.2023. [PMID: 38164567 PMCID: PMC10913042 DOI: 10.1523/eneuro.0192-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 11/03/2023] [Accepted: 11/13/2023] [Indexed: 01/03/2024] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is important in the development and maintenance of neurons and their plasticity. Hippocampal BDNF has been implicated in Alzheimer's disease (AD) because hippocampal levels in AD patients and AD animal models are often downregulated, suggesting that reduced BDNF contributes to AD. However, the location where hippocampal BDNF protein is most highly expressed, the mossy fiber (MF) axons of dentate gyrus granule cells (GCs), has been understudied, and not in controlled conditions. Therefore, we evaluated MF BDNF protein in the Tg2576 mouse model of AD. Tg2576 and wild-type (WT) mice of both sexes were examined at 2-3 months of age, when amyloid-β (Aβ) is present in neurons but plaques are absent, and 11-20 months of age, after plaque accumulation. As shown previously, WT mice exhibited high levels of MF BDNF protein. Interestingly, there was no significant decline with age in either the genotype or sex. Notably, MF BDNF protein was correlated with GC ΔFosB, a transcription factor that increases after 1-2 weeks of elevated neuronal activity. We also report the novel finding that Aβ in GCs or the GC layer was minimal even at old ages. The results indicate that MF BDNF is stable in the Tg2576 mouse, and MF BDNF may remain unchanged due to increased GC neuronal activity, since BDNF expression is well known to be activity dependent. The resistance of GCs to long-term Aβ accumulation provides an opportunity to understand how to protect vulnerable neurons from increased Aβ levels and therefore has translational implications.
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Affiliation(s)
- Chiara Criscuolo
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Department of Child & Adolescent Psychiatry, NewYork University Grossman School of Medicine, New York, NY 10016
| | - Elissavet Chartampila
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Stephen D Ginsberg
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Department of Neuroscience & Physiology, NewYork University Grossman School of Medicine, New York, NY 10016
- Psychiatry, NewYork University Grossman School of Medicine, New York, NY 10016
- NYU Neuroscience Institute, NewYork University Grossman School of Medicine, New York, NY 10016
| | - Helen E Scharfman
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Department of Child & Adolescent Psychiatry, NewYork University Grossman School of Medicine, New York, NY 10016
- Department of Neuroscience & Physiology, NewYork University Grossman School of Medicine, New York, NY 10016
- NYU Neuroscience Institute, NewYork University Grossman School of Medicine, New York, NY 10016
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Alcantara-Gonzalez D, Kennedy M, Criscuolo C, Botterill J, Scharfman HE. Increased excitability of dentate gyrus mossy cells occurs early in life in the Tg2576 model of Alzheimer's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.09.579729. [PMID: 38645244 PMCID: PMC11027210 DOI: 10.1101/2024.02.09.579729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
INTRODUCTION Hyperexcitability in Alzheimer's disease (AD) emerge early and contribute to disease progression. The dentate gyrus (DG) is implicated in hyperexcitability in AD. We hypothesized that mossy cells (MCs), regulators of DG excitability, contribute to early hyperexcitability in AD. Indeed, MCs generate hyperexcitability in epilepsy. METHODS Using the Tg2576 model and WT mice (∼1month-old), we compared MCs electrophysiologically, assessed c-Fos activity marker, Aβ expression and mice performance in a hippocampal-dependent memory task. RESULTS Tg2576 MCs exhibit increased spontaneous excitatory events and decreased inhibitory currents, increasing the charge transfer excitation/inhibition ratio. Tg2576 MC intrinsic excitability was enhanced, and showed higher c-Fos, intracellular Aβ expression, and axon sprouting. Granule cells only showed changes in synaptic properties, without intrinsic changes. The effects occurred before a memory task is affected. DISCUSSION Early electrophysiological and morphological alterations in Tg2576 MCs are consistent with enhanced excitability, suggesting an early role in DG hyperexcitability and AD pathophysiology. HIGHLIGHTS ∘ MCs from 1 month-old Tg2576 mice had increased spontaneous excitatory synaptic input. ∘ Tg2576 MCs had reduced spontaneous inhibitory synaptic input. ∘ Several intrinsic properties were abnormal in Tg2576 MCs. ∘ Tg2576 GCs had enhanced synaptic excitation but no changes in intrinsic properties. ∘ Tg2576 MCs exhibited high c-Fos expression, soluble Aβ and axonal sprouting.
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10
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Altunkaya A, Deichsel C, Kreuzer M, Nguyen DM, Wintergerst AM, Rammes G, Schneider G, Fenzl T. Altered sleep behavior strengthens face validity in the ArcAβ mouse model for Alzheimer's disease. Sci Rep 2024; 14:951. [PMID: 38200079 PMCID: PMC10781983 DOI: 10.1038/s41598-024-51560-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 01/06/2024] [Indexed: 01/12/2024] Open
Abstract
Demographic changes will expand the number of senior citizens suffering from Alzheimer's disease (AD). Key aspects of AD pathology are sleep impairments, associated with onset and progression of AD. AD mouse models may provide insights into mechanisms of AD-related sleep impairments. Such models may also help to establish new biomarkers predicting AD onset and monitoring AD progression. The present study aimed to establish sleep-related face validity of a widely used mouse model of AD (ArcAβ model) by comprehensively characterizing its baseline sleep/wake behavior. Chronic EEG recordings were performed continuously on four consecutive days in freely behaving mice. Spectral and temporal sleep/wake parameters were assessed and analyzed. EEG recordings showed decreased non-rapid eye movement sleep (NREMS) and increased wakefulness in transgenic mice (TG). Vigilance state transitions were different in TG mice when compared to wildtype littermates (WT). During NREMS, TG mice had lower power between 1 and 5 Hz and increased power between 5 and 30 Hz. Sleep spindle amplitudes in TG mice were lower. Our study strongly provides sleep-linked face validity for the ArcAβ model. These findings extend the potential of the mouse model to investigate mechanisms of AD-related sleep impairments and the impact of sleep impairments on the development of AD.
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Affiliation(s)
- Alp Altunkaya
- Department of Anesthesiology and Intensive Care, School of Medicine and Health, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Cassandra Deichsel
- Department of Anesthesiology and Intensive Care, School of Medicine and Health, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Matthias Kreuzer
- Department of Anesthesiology and Intensive Care, School of Medicine and Health, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Duy-Minh Nguyen
- Department of Anesthesiology and Intensive Care, School of Medicine and Health, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Ann-Marie Wintergerst
- Department of Anesthesiology and Intensive Care, School of Medicine and Health, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Gerhard Rammes
- Department of Anesthesiology and Intensive Care, School of Medicine and Health, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Gerhard Schneider
- Department of Anesthesiology and Intensive Care, School of Medicine and Health, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Thomas Fenzl
- Department of Anesthesiology and Intensive Care, School of Medicine and Health, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany.
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Ohno M. A Strategy for Allowing Earlier Diagnosis and Rigorous Evaluation of BACE1 Inhibitors in Preclinical Alzheimer's Disease. J Alzheimers Dis 2024; 99:431-445. [PMID: 38701146 DOI: 10.3233/jad-231451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
Given continued failure of BACE1 inhibitor programs at symptomatic and prodromal stages of Alzheimer's disease (AD), clinical trials need to target the earlier preclinical stage. However, trial design is complex in this population with negative diagnosis of classical hippocampal amnesia on standard memory tests. Besides recent advances in brain imaging, electroencephalogram, and fluid-based biomarkers, new cognitive markers should be established for earlier diagnosis that can optimize recruitment to BACE1 inhibitor trials in presymptomatic AD. Notably, accelerated long-term forgetting (ALF) is emerging as a sensitive cognitive measure that can discriminate between asymptomatic individuals with high risks for developing AD and healthy controls. ALF is a form of declarative memory impairment characterized by increased forgetting rates over longer delays (days to months) despite normal storage within the standard delays of testing (20-60 min). Therefore, ALF may represent a harbinger of preclinical dementia and the impairment of systems memory consolidation, during which memory traces temporarily stored in the hippocampus become gradually integrated into cortical networks. This review provides an overview of the utility of ALF in a rational design of next-generation BACE1 inhibitor trials in preclinical AD. I explore potential mechanisms underlying ALF and relevant early-stage biomarkers useful for BACE1 inhibitor evaluation, including synaptic protein alterations, astrocytic dysregulation and neuron hyperactivity in the hippocampal-cortical network. Furthermore, given the physiological role of the isoform BACE2 as an AD-suppressor gene, I also discuss the possible association between the poor selectivity of BACE1 inhibitors and their side effects (e.g., cognitive worsening) in prior clinical trials.
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Affiliation(s)
- Masuo Ohno
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA
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12
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Ueda S, Kuzuya A, Kawata M, Okawa K, Honjo C, Wada T, Matsumoto M, Goto K, Miyamoto M, Yonezawa A, Tanabe Y, Ikeda A, Kinoshita A, Takahashi R. Acute inhibition of AMPA receptors by perampanel reduces amyloid β-protein levels by suppressing β-cleavage of APP in Alzheimer's disease models. FASEB J 2023; 37:e23252. [PMID: 37850918 DOI: 10.1096/fj.202300837r] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 08/29/2023] [Accepted: 09/27/2023] [Indexed: 10/19/2023]
Abstract
Hippocampal hyperexcitability is a promising therapeutic target to prevent Aβ deposition in AD since enhanced neuronal activity promotes presynaptic Aβ production and release. This article highlights the potential application of perampanel (PER), an AMPA receptor (AMPAR) antagonist approved for partial seizures, as a therapeutic agent for AD. Using transgenic AD mice combined with in vivo brain microdialysis and primary neurons under oligomeric Aβ-evoked neuronal hyperexcitability, the acute effects of PER on Aβ metabolism were investigated. A single oral administration of PER rapidly decreased ISF Aβ40 and Aβ42 levels in the hippocampus of J20, APP transgenic mice, without affecting the Aβ40 /Aβ42 ratio; 5 mg/kg PER resulted in declines of 20% and 31%, respectively. Moreover, PER-treated J20 manifested a marked decrease in hippocampal APP βCTF levels with increased FL-APP levels. Consistently, acute treatment of PER reduced sAPPβ levels, a direct byproduct of β-cleavage of APP, released to the medium in primary neuronal cultures under oligomeric Aβ-induced neuronal hyperexcitability. To further evaluate the effect of PER on ISF Aβ clearance, a γ-secretase inhibitor was administered to J20 1 h after PER treatment. PER did not influence the elimination of ISF Aβ, indicating that the acute effect of PER is predominantly on Aβ production. In conclusion, acute treatment of PER reduces Aβ production by suppressing β-cleavage of amyloid-β precursor protein effectively, indicating a potential effect of PER against Aβ pathology in AD.
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Affiliation(s)
- Sakiho Ueda
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Akira Kuzuya
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Masayoshi Kawata
- Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan
| | - Kohei Okawa
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Chika Honjo
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takafumi Wada
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Mizuki Matsumoto
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kazuya Goto
- Department of Regulation of Neurocognitive Disorders, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Masakazu Miyamoto
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Atsushi Yonezawa
- Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan
| | - Yasuto Tanabe
- Department of Regulation of Neurocognitive Disorders, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Ayae Kinoshita
- School of Human Health Sciences, Faculty of Medicine, Kyoto University, Kyoto, Japan
| | - Ryosuke Takahashi
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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13
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Lisgaras CP, Scharfman HE. Interictal spikes in Alzheimer's disease: Preclinical evidence for dominance of the dentate gyrus and cholinergic control by the medial septum. Neurobiol Dis 2023; 187:106294. [PMID: 37714307 PMCID: PMC10617404 DOI: 10.1016/j.nbd.2023.106294] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 09/17/2023] Open
Abstract
Interictal spikes (IIS) are a common type of abnormal electrical activity in Alzheimer's disease (AD) and preclinical models. The brain regions where IIS are largest are not known but are important because such data would suggest sites that contribute to IIS generation. Because hippocampus and cortex exhibit altered excitability in AD models, we asked which areas dominate the activity during IIS along the cortical-CA1-dentate gyrus (DG) dorso-ventral axis. Because medial septal (MS) cholinergic neurons are overactive when IIS typically occur, we also tested the novel hypothesis that silencing the MS cholinergic neurons selectively would reduce IIS. We used mice that simulate aspects of AD: Tg2576 mice, presenilin 2 (PS2) knockout mice and Ts65Dn mice. To selectively silence MS cholinergic neurons, Tg2576 mice were bred with choline-acetyltransferase (ChAT)-Cre mice and offspring were injected in the MS with AAV encoding inhibitory designer receptors exclusively activated by designer drugs (DREADDs). We recorded local field potentials along the cortical-CA1-DG axis using silicon probes during wakefulness, slow-wave sleep (SWS) and rapid eye movement (REM) sleep. We detected IIS in all transgenic or knockout mice but not age-matched controls. IIS were detectable throughout the cortical-CA1-DG axis and occurred primarily during REM sleep. In all 3 mouse lines, IIS amplitudes were significantly greater in the DG granule cell layer vs. CA1 pyramidal layer or overlying cortex. Current source density analysis showed robust and early current sources in the DG, and additional sources in CA1 and the cortex also. Selective chemogenetic silencing of MS cholinergic neurons significantly reduced IIS rate during REM sleep without affecting the overall duration, number of REM bouts, latency to REM sleep, or theta power during REM. Notably, two control interventions showed no effects. Consistent maximal amplitude and strong current sources of IIS in the DG suggest that the DG is remarkably active during IIS. In addition, selectively reducing MS cholinergic tone, at times when MS is hyperactive, could be a new strategy to reduce IIS in AD.
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Affiliation(s)
- Christos Panagiotis Lisgaras
- Departments of Child & Adolescent Psychiatry, Neuroscience & Physiology, and Psychiatry, and the Neuroscience Institute New York University Langone Health, 550 First Ave., New York, NY 10016, United States of America; Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, New York State Office of Mental Health, 140 Old Orangeburg Road, Bldg. 35, Orangeburg, NY 10962, United States of America.
| | - Helen E Scharfman
- Departments of Child & Adolescent Psychiatry, Neuroscience & Physiology, and Psychiatry, and the Neuroscience Institute New York University Langone Health, 550 First Ave., New York, NY 10016, United States of America; Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, New York State Office of Mental Health, 140 Old Orangeburg Road, Bldg. 35, Orangeburg, NY 10962, United States of America
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14
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Vande Vyver M, Daeninck L, De Smet G, Aourz N, Sahu S, Engelborghs S, Pauwels K, De Bundel D, Smolders I. The intracerebral injection of Aβ 1-42 oligomers does not invariably alter seizure susceptibility in mice. Front Aging Neurosci 2023; 15:1239140. [PMID: 37744393 PMCID: PMC10512828 DOI: 10.3389/fnagi.2023.1239140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/22/2023] [Indexed: 09/26/2023] Open
Abstract
Objectives Epileptiform activity and seizures are present in patients with Alzheimer's disease (AD) and genetic animal models of AD. Amyloid beta 1-42 (Aβ1-42) oligomers are thought to be crucial in AD and can cause neuronal hyperexcitability in vitro. However, it is unclear whether these Aβ1-42 oligomers cause the increased seizure susceptibility in vivo in people with AD and in AD animal models, nor via which mechanisms it would do so. We investigated this question by injecting Aβ1-42 oligomers intracerebrally in mice and assessed its impact on seizure susceptibility. Materials and methods We performed a single intracerebral injection of synthetic Aβ1-42 oligomers or scrambled Aβ1-42 in NMRI mice in three different cohorts and subjected them to an i.v. infusion of a chemoconvulsant. We evoked the seizures 1.5 h, 1 week, or 3 weeks after the intracerebral injection of Aβ1-42 oligomers, covering also the timepoints and injection locations that were used by others in similar experimental set-ups. Results With a thioflavine T assay and transmission electron microscopy we confirmed that Aβ1-42 monomers spontaneously aggregated to oligomers. We did not find an effect of Aβ1-42 oligomers on susceptibility to seizures - evoked 1.5 h, 1 week or 3 weeks - after their intracerebral injection. Significance The lack of effect of Aβ1-42 oligomers on seizure susceptibility in our experiments contrasts with recent findings in similar experimental set-ups. Contradicting conclusions are frequent in experiments with Aβ1-42 and they are often attributed to subtle differences in the various aggregation forms of the Aβ1-42 used in different experiments. We confirmed the presence of Aβ1-42 oligomers with state-of-the-art methods but cannot ascertain that the protein aggregates we used are identical to those used by others. Whether our findings or those previously published best represent the role of Aβ1-42 oligomers on seizures in AD remains unclear.
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Affiliation(s)
- Maxime Vande Vyver
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
- Department of Neurology and Bru-BRAIN, Universitair Ziekenhuis Brussel, Brussels, Belgium
- NEUR Research Group, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
- Department of Biomedical Sciences, Reference Center for Biological Markers of Dementia (BIODEM), University of Antwerp, Antwerp, Belgium
| | - Louise Daeninck
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
| | - Gino De Smet
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
| | - Najat Aourz
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
| | - Surajit Sahu
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
| | - Sebastiaan Engelborghs
- Department of Neurology and Bru-BRAIN, Universitair Ziekenhuis Brussel, Brussels, Belgium
- NEUR Research Group, Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
- Department of Biomedical Sciences, Reference Center for Biological Markers of Dementia (BIODEM), University of Antwerp, Antwerp, Belgium
| | - Kris Pauwels
- RESEARCH Department, Vrije Universiteit Brussel, Brussels, Belgium
| | - Dimitri De Bundel
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology (EFAR), Center for Neurosciences (C4N), Vrije Universiteit Brussel, Brussels, Belgium
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15
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Soula M, Maslarova A, Harvey RE, Valero M, Brandner S, Hamer H, Fernández‐Ruiz A, Buzsáki G. Interictal epileptiform discharges affect memory in an Alzheimer's disease mouse model. Proc Natl Acad Sci U S A 2023; 120:e2302676120. [PMID: 37590406 PMCID: PMC10450667 DOI: 10.1073/pnas.2302676120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 07/06/2023] [Indexed: 08/19/2023] Open
Abstract
Interictal epileptiform discharges (IEDs) are transient abnormal electrophysiological events commonly observed in epilepsy patients but are also present in other neurological diseases, such as Alzheimer's disease (AD). Understanding the role IEDs have on the hippocampal circuit is important for our understanding of the cognitive deficits seen in epilepsy and AD. We characterize and compare the IEDs of human epilepsy patients from microwire hippocampal recording with those of AD transgenic mice with implanted multilayer hippocampal silicon probes. Both the local field potential features and firing patterns of pyramidal cells and interneurons were similar in the mouse and human. We found that as IEDs emerged from the CA3-1 circuits, they recruited pyramidal cells and silenced interneurons, followed by post-IED suppression. IEDs suppressed the incidence and altered the properties of physiological sharp-wave ripples, altered their physiological properties, and interfered with the replay of place field sequences in a maze. In addition, IEDs in AD mice inversely correlated with daily memory performance. Together, our work implies that IEDs may present a common and epilepsy-independent phenomenon in neurodegenerative diseases that perturbs hippocampal-cortical communication and interferes with memory.
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Affiliation(s)
- Marisol Soula
- Neuroscience Institute, Langone Medical Center, New York University, New York, NY10016
| | - Anna Maslarova
- Neuroscience Institute, Langone Medical Center, New York University, New York, NY10016
- Department of Neurosurgery, Erlangen University Hospital, Friedrich Alexander University Erlangen-Nuremberg, 91054Erlangen, Germany
| | - Ryan E. Harvey
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY14853
| | - Manuel Valero
- Hospital del Mar Medical Research Institute, Barcelona Biomedical Research Park, Barcelona08003, Spain
| | - Sebastian Brandner
- Department of Neurosurgery, Erlangen University Hospital, Friedrich Alexander University Erlangen-Nuremberg, 91054Erlangen, Germany
| | - Hajo Hamer
- Department of Neurology, Epilepsy Center, Erlangen University Hospital, Friedrich Alexander University Erlangen-Nuremberg, 91054Erlangen, Germany
| | | | - György Buzsáki
- Neuroscience Institute, Langone Medical Center, New York University, New York, NY10016
- Department of Physiology and Neuroscience, Langone Medical Center, New York University, New York, NY10016
- Department of Neurology, Langone Medical Center, New York University, New York, NY10016
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16
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Lisgaras CP, Scharfman HE. Interictal Spikes in Alzheimer's Disease: Preclinical Evidence for Dominance of the Dentate Gyrus and Cholinergic Control by Medial Septum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.24.537999. [PMID: 37163065 PMCID: PMC10168266 DOI: 10.1101/2023.04.24.537999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
HIGHLIGHTS Interictal spikes (IIS) occur in 3 mouse lines with Alzheimer's disease featuresIIS in all 3 mouse lines were most frequent during rapid eye movement (REM) sleepThe dentate gyrus showed larger IIS and earlier current sources vs. CA1 or cortexChemogenetic silencing of medial septum (MS) cholinergic neurons reduced IIS during REMMS silencing did not change REM latency, duration, number of bouts or theta power. Interictal spikes (IIS) are a common type of abnormal electrical activity in Alzheimer's disease (AD) and preclinical models. The brain regions where IIS are largest are not known but are important because such data would suggest sites that contribute to IIS generation. Because hippocampus and cortex exhibit altered excitability in AD models, we asked which areas dominate the activity during IIS along the cortical-CA1-dentate gyrus (DG) dorso-ventral axis. Because medial septal (MS) cholinergic neurons are overactive when IIS typically occur, we also tested the novel hypothesis that silencing the MS cholinergic neurons selectively would reduce IIS.We used mice that simulate aspects of AD: Tg2576 mice, presenilin 2 (PS2) knockout mice and Ts65Dn mice. To selectively silence MS cholinergic neurons, Tg2576 mice were bred with choline-acetyltransferase (ChAT)-Cre mice and offspring were injected in the MS with AAV encoding inhibitory designer receptors exclusively activated by designer drugs (DREADDs). We recorded local field potentials along the cortical-CA1-DG axis using silicon probes during wakefulness, slow-wave sleep (SWS) and rapid eye movement (REM) sleep.We detected IIS in all transgenic or knockout mice but not age-matched controls. IIS were detectable throughout the cortical-CA1-DG axis and occurred primarily during REM sleep. In all 3 mouse lines, IIS amplitudes were significantly greater in the DG granule cell layer vs. CA1 pyramidal layer or overlying cortex. Current source density analysis showed robust and early current sources in the DG, and additional sources in CA1 and the cortex also. Selective chemogenetic silencing of MS cholinergic neurons significantly reduced IIS rate during REM sleep without affecting the overall duration, number of REM bouts, latency to REM sleep, or theta power during REM. Notably, two control interventions showed no effects.Consistent maximal amplitude and strong current sources of IIS in the DG suggest that the DG is remarkably active during IIS. In addition, selectively reducing MS cholinergic tone, at times when MS is hyperactive, could be a new strategy to reduce IIS in AD.
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17
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Fang Y, Si X, Wang J, Wang Z, Chen Y, Liu Y, Yan Y, Tian J, Zhang B, Pu J. Alzheimer Disease and Epilepsy: A Mendelian Randomization Study. Neurology 2023; 101:e399-e409. [PMID: 37225432 PMCID: PMC10435057 DOI: 10.1212/wnl.0000000000207423] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 04/03/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Observational studies suggested a bidirectional relationship between Alzheimer disease (AD) and epilepsies. However, it remains debated whether and in which direction a causal association exists. This study aims to explore the relationship between genetic predisposition to AD, CSF biomarkers of AD (β-amyloid [Aβ] 42 and phosphorylated tau [pTau]), and epilepsies with 2-sample, bidirectional Mendelian randomization (MR) method. METHODS Genetic instruments were obtained from large-scale genome-wide meta-analysis of AD (Ncase/proxy = 111,326, Ncontrol = 677,663), CSF biomarkers of AD (Aβ42 and pTau, N = 13,116), and epilepsy (Ncase = 15,212, Ncontrol = 29,677) of European ancestry. Epilepsy phenotypes included all epilepsy, generalized epilepsy, focal epilepsy, childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy, generalized epilepsy with tonic-clonic seizures, focal epilepsy with hippocampal sclerosis (focal HS), and lesion-negative focal epilepsy. Main analyses were performed using generalized summary data-based MR. Sensitivity analyses included inverse variance weighted, MR pleiotropy residual sum and outlier, MR-Egger, weighted mode, and weighted median. RESULTS For forward analysis, genetic predisposition to AD was associated with an increased risk of generalized epilepsy (odds ratio [OR] 1.053, 95% CI 1.002-1.105, p = 0.038) and focal HS (OR 1.013, 95% CI 1.004-1.022, p = 0.004). These associations were consistent across sensitivity analyses and replicated using a separate set of genetic instruments from another AD genome-wide association study. For reverse analysis, there was a suggestive effect of focal HS on AD (OR 3.994, 95% CI 1.172-13.613, p = 0.027). In addition, genetically predicted lower CSF Aβ42 was associated with an increased risk of generalized epilepsy (β = 0.090, 95% CI 0.022-0.158, p = 0.010). DISCUSSION This MR study supports a causal link between AD, amyloid pathology, and generalized epilepsy. This study also indicates a close association between AD and focal HS. More effort should be made to screen seizure in AD, unravel its clinical implications, and explore its role as a putative modifiable risk factor.
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Affiliation(s)
- Yi Fang
- From the Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoli Si
- From the Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jiali Wang
- From the Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhiyun Wang
- From the Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ying Chen
- From the Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Liu
- From the Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yaping Yan
- From the Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jun Tian
- From the Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Baorong Zhang
- From the Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jiali Pu
- From the Department of Neurology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
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18
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Musaeus CS, Frederiksen KS, Andersen BB, Høgh P, Kidmose P, Fabricius M, Hribljan MC, Hemmsen MC, Rank ML, Waldemar G, Kjær TW. Detection of subclinical epileptiform discharges in Alzheimer's disease using long-term outpatient EEG monitoring. Neurobiol Dis 2023; 183:106149. [PMID: 37196736 DOI: 10.1016/j.nbd.2023.106149] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/26/2023] [Accepted: 05/09/2023] [Indexed: 05/19/2023] Open
Abstract
BACKGROUND In patients with Alzheimer's disease (AD) without clinical seizures, up to half have epileptiform discharges on long-term in-patient electroencephalography (EEG) recordings. Long-term in-patient monitoring is obtrusive, and expensive as compared to outpatient monitoring. No studies have so far investigated if long-term outpatient EEG monitoring is able to identify epileptiform discharges in AD. Our aim is to investigate if epileptiform discharges as measured with ear-EEG are more common in patients with AD compared to healthy elderly controls (HC). METHODS In this longitudinal observational study, 24 patients with mild to moderate AD and 15 age-matched HC were included in the analysis. Patients with AD underwent up to three ear-EEG recordings, each lasting up to two days, within 6 months. RESULTS The first recording was defined as the baseline recording. At baseline, epileptiform discharges were detected in 75.0% of patients with AD and in 46.7% of HC (p-value = 0.073). The spike frequency (spikes or sharp waves/24 h) was significantly higher in patients with AD as compared to HC with a risk ratio of 2.90 (CI: 1.77-5.01, p < 0.001). Most patients with AD (91.7%) showed epileptiform discharges when combining all ear-EEG recordings. CONCLUSIONS Long-term ear-EEG monitoring detects epileptiform discharges in most patients with AD with a three-fold increased spike frequency compared to HC, which most likely originates from the temporal lobes. Since most patients showed epileptiform discharges with multiple recordings, elevated spike frequency should be considered a marker of hyperexcitability in AD.
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Affiliation(s)
- Christian Sandøe Musaeus
- Danish Dementia Research Centre, Department of Neurology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark.
| | - Kristian Steen Frederiksen
- Danish Dementia Research Centre, Department of Neurology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Birgitte Bo Andersen
- Danish Dementia Research Centre, Department of Neurology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Peter Høgh
- Regional Dementia Research Centre, Department of Neurology, Zealand University Hospital, Roskilde, Denmark; Department of Clinical Medicine, University of Copenhagen, Denmark
| | - Preben Kidmose
- Department of Electrical and Computer Engineering, Aarhus University, Aarhus N, Denmark
| | - Martin Fabricius
- Department of Clinical Neurophysiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Melita Cacic Hribljan
- Department of Clinical Neurophysiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | | | | | - Gunhild Waldemar
- Danish Dementia Research Centre, Department of Neurology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Denmark
| | - Troels Wesenberg Kjær
- Danish Dementia Research Centre, Department of Neurology, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
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Criscuolo C, Chartampila E, Ginsberg SD, Scharfman HE. Stability of dentate gyrus granule cell mossy fiber BDNF protein expression with age and resistance of granule cells to Alzheimer's disease neuropathology in a mouse model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.07.539742. [PMID: 37214931 PMCID: PMC10197599 DOI: 10.1101/2023.05.07.539742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The neurotrophin brain-derived neurotrophic factor (BDNF) is important in development and maintenance of neurons and their plasticity. Hippocampal BDNF has been implicated Alzheimer's disease (AD) because hippocampal levels in AD patients and AD animal models are consistently downregulated, suggesting that reduced BDNF contributes to AD. However, the location where hippocampal BDNF protein is most highly expressed, the mossy fiber (MF) axons of dentate gyrus (DG) granule cells (GCs), has been understudied, and never in controlled in vivo conditions. We examined MF BDNF protein in the Tg2576 mouse model of AD. Tg2576 and wild type (WT) mice of both sexes were examined at 2-3 months of age, when amyloid-β (Aβ) is present in neurons but plaques are absent, and 11-20 months of age, after plaque accumulation. As shown previously, WT mice exhibited high levels of MF BDNF protein. Interestingly, there was no significant decline with age in either genotype or sex. Notably, we found a correlation between MF BDNF protein and GC ΔFosB, a transcription factor that increases after 1-2 weeks of elevated neuronal activity. Remarkably, there was relatively little evidence of Aβ in GCs or the GC layer even at old ages. Results indicate MF BDNF is stable in the Tg2576 mouse, and MF BDNF may remain unchanged due to increased GC neuronal activity, since BDNF expression is well known to be activity-dependent. The resistance of GCs to long-term Aβ accumulation provides an opportunity to understand how to protect other vulnerable neurons from increased Aβ levels and therefore has translational implications.
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Affiliation(s)
- Chiara Criscuolo
- Center for Dementia Research, the Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, 10962, USA
- Department of Child & Adolescent Psychiatry, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Elissavet Chartampila
- Center for Dementia Research, the Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, 10962, USA
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Stephen D Ginsberg
- Center for Dementia Research, the Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, 10962, USA
- Department of Neuroscience & Physiology, New York University Grossman School of Medicine, New York, NY, 10016, USA
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, 10016, USA
- NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Helen E Scharfman
- Center for Dementia Research, the Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, 10962, USA
- Department of Child & Adolescent Psychiatry, New York University Grossman School of Medicine, New York, NY, 10016, USA
- Department of Neuroscience & Physiology, New York University Grossman School of Medicine, New York, NY, 10016, USA
- NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY, 10016, USA
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B Szabo A, Cattaud V, Bezzina C, Dard RF, Sayegh F, Gauzin S, Lejards C, Valton L, Rampon C, Verret L, Dahan L. Neuronal hyperexcitability in the Tg2576 mouse model of Alzheimer's disease - the influence of sleep and noradrenergic transmission. Neurobiol Aging 2023; 123:35-48. [PMID: 36634385 DOI: 10.1016/j.neurobiolaging.2022.11.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/23/2022]
Abstract
The link between Alzheimer's disease (AD) and network hypersynchrony - manifesting as epileptic activities - received considerable attention in the past decade. However, several questions remain unanswered as to its mechanistic underpinnings. Therefore, our objectives were (1) to better characterise epileptic events in the Tg2576 mouse model throughout the sleep-wake cycle and disease progression via electrophysiological recordings and (2) to explore the involvement of noradrenergic transmission in this pathological hypersynchrony. Over and above confirming the previously described early presence and predominance of epileptic events during rapid-eye-movement (REM) sleep, we also show that these events do not worsen with age and are highly phase-locked to the section of the theta cycle during REM sleep where hippocampal pyramidal cells reach their highest firing probability. Finally, we reveal an antiepileptic mechanism of noradrenergic transmission via α1-adrenoreceptors that could explain the intriguing distribution of epileptic events over the sleep-wake cycle in this model, with potential therapeutic implications in the treatment of the epileptic events occurring in many AD patients.
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Affiliation(s)
- Anna B Szabo
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France; Centre de recherche Cerveau et Cognition (CerCo), CNRS, UMR 5549, Toulouse Mind and Brain Institute (TMBI), University of Toulouse, University Paul Sabatier (UPS), Toulouse, France.
| | - Vanessa Cattaud
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Charlotte Bezzina
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Robin F Dard
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Fares Sayegh
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Sebastien Gauzin
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Camille Lejards
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Luc Valton
- Centre de recherche Cerveau et Cognition (CerCo), CNRS, UMR 5549, Toulouse Mind and Brain Institute (TMBI), University of Toulouse, University Paul Sabatier (UPS), Toulouse, France; Department of Neurology, Hôpital Pierre Paul Riquet - Purpan, Toulouse University Hospital, University of Toulouse, Toulouse, France
| | - Claire Rampon
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Laure Verret
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Lionel Dahan
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France.
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21
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Early impairments of visually-driven neuronal ensemble dynamics in the rTg4510 tauopathy mouse model. Neurobiol Dis 2023; 178:106012. [PMID: 36696792 DOI: 10.1016/j.nbd.2023.106012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/20/2023] [Accepted: 01/21/2023] [Indexed: 01/24/2023] Open
Abstract
Tau protein pathology is a hallmark of many neurodegenerative diseases, including Alzheimer's Disease or frontotemporal dementia. Synaptic dysfunction and abnormal visual evoked potentials have been reported in murine models of tauopathy, but little is known about the state of the network activity on a single neuronal level prior to brain atrophy. In the present study, oscillatory rhythms and single-cell calcium activity of primary visual cortex pyramidal neuron population were investigated in basal and light evoked states in the rTg4510 tauopathy mouse model prior to neurodegeneration. We found a decrease in their responsivity and overall activity which was insensitive to GABAergic modulation. Despite an enhancement of basal state coactivation of cortical pyramidal neurons, a loss of input-output synchronicity was observed. Dysfunction of cortical pyramidal function was also reflected in a reduction of basal theta oscillations and enhanced susceptibility to a sub-convulsive dose of pentylenetetrazol in rTg4510 mice. Our results unveil impairments in visual cortical pyramidal neuron processing and define aberrant oscillations as biomarker candidates in early stages of neurodegenerative tauopathies.
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22
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Rizzello E, Pimpinella D, Pignataro A, Titta G, Merenda E, Saviana M, Porcheddu G, Paolantoni C, Malerba F, Giorgi C, Curia G, Middei S, Marchetti C. Lamotrigine rescues neuronal alterations and prevents seizure-induced memory decline in an Alzheimer's disease mouse model. Neurobiol Dis 2023; 181:106106. [PMID: 37001613 DOI: 10.1016/j.nbd.2023.106106] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/17/2023] [Accepted: 03/25/2023] [Indexed: 03/31/2023] Open
Abstract
Epilepsy is a comorbidity associated with Alzheimer's disease (AD), often starting many years earlier than memory decline. Investigating this association in the early pre-symptomatic stages of AD can unveil new mechanisms of the pathology as well as guide the use of antiepileptic drugs to prevent or delay hyperexcitability-related pathological effects of AD. We investigated the impact of repeated seizures on hippocampal memory and amyloid-β (Aβ) load in pre-symptomatic Tg2576 mice, a transgenic model of AD. Seizure induction caused memory deficits and an increase in oligomeric Aβ42 and fibrillary species selectively in pre-symptomatic transgenic mice, and not in their wildtype littermates. Electrophysiological patch-clamp recordings in ex vivo CA1 pyramidal neurons and immunoblots were carried out to investigate the neuronal alterations associated with the behavioral outcomes of Tg2576 mice. CA1 pyramidal neurons exhibited increased intrinsic excitability and lower hyperpolarization-activated Ih current. CA1 also displayed lower expression of the hyperpolarization-activated cyclic nucleotide-gated HCN1 subunit, a protein already identified as downregulated in the AD human proteome. The antiepileptic drug lamotrigine restored electrophysiological alterations and prevented both memory deficits and the increase in extracellular Aβ induced by seizures. Thus our study provides evidence of pre-symptomatic hippocampal neuronal alterations leading to hyperexcitability and associated with both higher susceptibility to seizures and to AD-specific seizure-induced memory impairment. Our findings also provide a basis for the use of the antiepileptic drug lamotrigine as a way to counteract acceleration of AD induced by seizures in the early phases of the pathology.
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Soula M, Maslarova A, Harvey RE, Valero M, Brandner S, Hamer H, Fernández-Ruiz A, Buzsáki G. Interictal epileptiform discharges affect memory in an Alzheimer's Disease mouse model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528683. [PMID: 36824810 PMCID: PMC9949089 DOI: 10.1101/2023.02.15.528683] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Interictal epileptiform discharges (IEDs) are transient abnormal electrophysiological events commonly observed in epilepsy patients but are also present in other neurological disease, such as Alzheimer's Disease (AD). Understanding the role IEDs have on the hippocampal circuit is important for our understanding of the cognitive deficits seen in epilepsy and AD. We characterize and compare the IEDs of human epilepsy patients from microwire hippocampal recording with those of AD transgenic mice with implanted multi-layer hippocampal silicon probes. Both the local field potential features and firing patterns of pyramidal cells and interneurons were similar in mouse and human. We found that as IEDs emerged from the CA3-1 circuits, they recruited pyramidal cells and silenced interneurons, followed by post-IED suppression. IEDs suppressed the incidence and altered the properties of physiological sharp-wave ripples (SPW-Rs), altered their physiological properties, and interfered with the replay of place field sequences in a maze. In addition, IEDs in AD mice inversely correlated with daily memory performance. Together, our work implicates that IEDs may present a common and epilepsy-independent phenomenon in neurodegenerative diseases that perturbs hippocampal-cortical communication and interferes with memory. Significant Statement Prevalence of neurodegenerative diseases and the number of people with dementia is increasing steadily. Therefore, novel treatment strategies for learning and memory disorders are urgently necessary. IEDs, apart from being a surrogate for epileptic brain regions, have also been linked to cognitive decline. Here we report that IEDs in human epilepsy patients and AD mouse models have similar local field potential characteristics and associated firing patterns of pyramidal cells and interneurons. Mice with more IEDs displayed fewer hippocampal SPW-Rs, poorer replay of spatial trajectories, and decreased memory performance. IED suppression is an unexplored target to treat cognitive dysfunction in neurodegenerative diseases.
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24
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Vande Vyver M, Barker‐Haliski M, Aourz N, Nagels G, Bjerke M, Engelborghs S, De Bundel D, Smolders I. Higher susceptibility to 6 Hz corneal kindling and lower responsiveness to antiseizure drugs in mouse models of Alzheimer's disease. Epilepsia 2022; 63:2703-2715. [PMID: 35775150 PMCID: PMC9804582 DOI: 10.1111/epi.17355] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 06/17/2022] [Accepted: 06/29/2022] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Epileptic spikes and seizures seem present early in the disease process of Alzheimer's disease (AD). However, it is unclear how soluble and insoluble amyloid beta (Aβ) and tau proteins affect seizure development in vivo. We aim to contribute to this field by assessing the vulnerability to 6 Hz corneal kindling of young female mice from two well-characterized transgenic AD models and by testing their responsiveness to selected antiseizure drugs (ASDs). METHODS We used 7-week-old triple transgenic (3xTg) mice that have both amyloid and tau mutations, and amyloid precursor protein Swedish/presenillin 1 dE9 (APP/PS1) mice, bearing only amyloid-related mutations. We assessed the absence of plaques via immunohistochemistry and analyzed the concentrations of both soluble and insoluble forms of Aβ1-42 and total tau (t-tau) in brain hippocampal and prefrontal cortical tissue. Seven-week-old mice of the different genotypes were subjected to the 6 Hz corneal kindling model. After kindling acquisition, we tested the anticonvulsant effects of three marketed ASDs (levetiracetam, brivaracetam, and lamotrigine) in fully kindled mice. RESULTS No Aβ plaques were present in either genotype. Soluble Aβ1-42 levels were increased in both AD genotypes, whereas insoluble Aβ1-42 concentrations were only elevated in APP/PS1 mice compared with their respective controls. Soluble and insoluble forms of t-tau were increased in 3xTg mice only. 3xTg and APP/PS1 mice displayed more severe seizures induced by 6 Hz corneal kindling from the first stimulation onward and were more rapidly kindled compared with control mice. In fully kindled AD mice, ASDs had less-pronounced anticonvulsive effects compared with controls. SIGNIFICANCE Mutations increasing Aβ only or both Aβ and tau in the brain enhance susceptibility for seizures and kindling in mice. The effect of ASDs on seizures measured by the Racine scale is less pronounced in both investigated AD models and suggests that seizures of young AD mice are more difficult to treat.
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Affiliation(s)
- Maxime Vande Vyver
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for NeurosciencesVrije Universiteit BrusselBrusselsBelgium,Department of NeurologyUniversitair Ziekenhuis BrusselJetteBelgium,Reference Center for Biological Markers of Dementia (BIODEM), Department of Biomedical SciencesUniversity of AntwerpAntwerpBelgium,Neuroprotection and Neuromodulation (NEUR), Center for NeurosciencesVrije Universiteit BrusselBrusselsBelgium
| | | | - Najat Aourz
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for NeurosciencesVrije Universiteit BrusselBrusselsBelgium
| | - Guy Nagels
- Department of NeurologyUniversitair Ziekenhuis BrusselJetteBelgium,Department of AI Supported Modelling in Clinical Sciences (AIMS)Vrije Universiteit BrusselBrusselsBelgium
| | - Maria Bjerke
- Neuroprotection and Neuromodulation (NEUR), Center for NeurosciencesVrije Universiteit BrusselBrusselsBelgium,Department of NeurochemistryUniversitair Ziekenhuis BrusselBrusselsBelgium
| | - Sebastiaan Engelborghs
- Department of NeurologyUniversitair Ziekenhuis BrusselJetteBelgium,Reference Center for Biological Markers of Dementia (BIODEM), Department of Biomedical SciencesUniversity of AntwerpAntwerpBelgium,Neuroprotection and Neuromodulation (NEUR), Center for NeurosciencesVrije Universiteit BrusselBrusselsBelgium
| | - Dimitri De Bundel
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for NeurosciencesVrije Universiteit BrusselBrusselsBelgium
| | - Ilse Smolders
- Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Research Group Experimental Pharmacology, Center for NeurosciencesVrije Universiteit BrusselBrusselsBelgium
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Piccialli I, Sisalli MJ, de Rosa V, Boscia F, Tedeschi V, Secondo A, Pannaccione A. Increased K V2.1 Channel Clustering Underlies the Reduction of Delayed Rectifier K + Currents in Hippocampal Neurons of the Tg2576 Alzheimer's Disease Mouse. Cells 2022; 11:cells11182820. [PMID: 36139395 PMCID: PMC9497218 DOI: 10.3390/cells11182820] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 09/01/2022] [Accepted: 09/07/2022] [Indexed: 11/30/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by the progressive deterioration of cognitive functions. Cortical and hippocampal hyperexcitability intervenes in the pathological derangement of brain activity leading to cognitive decline. As key regulators of neuronal excitability, the voltage-gated K+ channels (KV) might play a crucial role in the AD pathophysiology. Among them, the KV2.1 channel, the main α subunit mediating the delayed rectifier K+ currents (IDR) and controlling the intrinsic excitability of pyramidal neurons, has been poorly examined in AD. In the present study, we investigated the KV2.1 protein expression and activity in hippocampal neurons from the Tg2576 mouse, a widely used transgenic model of AD. To this aim we performed whole-cell patch-clamp recordings, Western blotting, and immunofluorescence analyses. Our Western blotting results reveal that KV2.1 was overexpressed in the hippocampus of 3-month-old Tg2576 mice and in primary hippocampal neurons from Tg2576 mouse embryos compared with the WT counterparts. Electrophysiological experiments unveiled that the whole IDR were reduced in the Tg2576 primary neurons compared with the WT neurons, and that this reduction was due to the loss of the KV2.1 current component. Moreover, we found that the reduction of the KV2.1-mediated currents was due to increased channel clustering, and that glutamate, a stimulus inducing KV2.1 declustering, was able to restore the IDR to levels comparable to those of the WT neurons. These findings add new information about the dysregulation of ionic homeostasis in the Tg2576 AD mouse model and identify KV2.1 as a possible player in the AD-related alterations of neuronal excitability.
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26
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Anti-epileptogenic effects of synaptic vesicle protein 2 A modulation in a mouse model of Alzheimer’s disease. Epilepsy Res 2022; 186:106994. [DOI: 10.1016/j.eplepsyres.2022.106994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 07/18/2022] [Accepted: 08/01/2022] [Indexed: 11/21/2022]
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27
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Kawabata S. Excessive/Aberrant and Maladaptive Synaptic Plasticity: A Hypothesis for the Pathogenesis of Alzheimer’s Disease. Front Aging Neurosci 2022; 14:913693. [PMID: 35865745 PMCID: PMC9294348 DOI: 10.3389/fnagi.2022.913693] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/08/2022] [Indexed: 01/01/2023] Open
Abstract
The amyloid hypothesis for the pathogenesis of Alzheimer’s disease (AD) is widely accepted. Last year, the US Food and Drug Administration considered amyloid-β peptide (Aβ) as a surrogate biomarker and approved an anti-Aβ antibody, aducanumab, although its effectiveness in slowing the progression of AD is still uncertain. This approval has caused a great deal of controversy. Opinions are divided about whether there is enough evidence to definitely consider Aβ as a causative substance of AD. To develop this discussion constructively and to discover the most suitable therapeutic interventions in the end, an alternative persuasive hypothesis needs to emerge to better explain the facts. In this paper, I propose a hypothesis that excessive/aberrant and maladaptive synaptic plasticity is the pathophysiological basis for AD.
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Targa Dias Anastacio H, Matosin N, Ooi L. Neuronal hyperexcitability in Alzheimer's disease: what are the drivers behind this aberrant phenotype? Transl Psychiatry 2022; 12:257. [PMID: 35732622 PMCID: PMC9217953 DOI: 10.1038/s41398-022-02024-7] [Citation(s) in RCA: 78] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/01/2022] [Accepted: 06/08/2022] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder leading to loss of cognitive abilities and ultimately, death. With no cure available, limited treatments mostly focus on symptom management. Identifying early changes in the disease course may provide new therapeutic targets to halt or reverse disease progression. Clinical studies have shown that cortical and hippocampal hyperactivity are a feature shared by patients in the early stages of disease, progressing to hypoactivity during later stages of neurodegeneration. The exact mechanisms causing neuronal excitability changes are not fully characterized; however, animal and cell models have provided insights into some of the factors involved in this phenotype. In this review, we summarize the evidence for neuronal excitability changes over the course of AD onset and progression and the molecular mechanisms underpinning these differences. Specifically, we discuss contributors to aberrant neuronal excitability, including abnormal levels of intracellular Ca2+ and glutamate, pathological amyloid β (Aβ) and tau, genetic risk factors, including APOE, and impaired inhibitory interneuron and glial function. In light of recent research indicating hyperexcitability could be a predictive marker of cognitive dysfunction, we further argue that the hyperexcitability phenotype could be leveraged to improve the diagnosis and treatment of AD, and present potential targets for future AD treatment development.
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Affiliation(s)
- Helena Targa Dias Anastacio
- grid.510958.0Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia ,grid.1007.60000 0004 0486 528XMolecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522 Australia
| | - Natalie Matosin
- grid.510958.0Illawarra Health and Medical Research Institute, Wollongong, NSW 2522 Australia ,grid.1007.60000 0004 0486 528XMolecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522 Australia
| | - Lezanne Ooi
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia. .,Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, 2522, Australia.
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29
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B. Szabo A, Cretin B, Gérard F, Curot J, J. Barbeau E, Pariente J, Dahan L, Valton L. Sleep: The Tip of the Iceberg in the Bidirectional Link Between Alzheimer's Disease and Epilepsy. Front Neurol 2022; 13:836292. [PMID: 35481265 PMCID: PMC9035794 DOI: 10.3389/fneur.2022.836292] [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: 12/15/2021] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
The observation that a pathophysiological link might exist between Alzheimer's disease (AD) and epilepsy dates back to the identification of the first cases of the pathology itself and is now strongly supported by an ever-increasing mountain of literature. An overwhelming majority of data suggests not only a higher prevalence of epilepsy in Alzheimer's disease compared to healthy aging, but also that AD patients with a comorbid epileptic syndrome, even subclinical, have a steeper cognitive decline. Moreover, clinical and preclinical investigations have revealed a marked sleep-related increase in the frequency of epileptic activities. This characteristic might provide clues to the pathophysiological pathways underlying this comorbidity. Furthermore, the preferential sleep-related occurrence of epileptic events opens up the possibility that they might hasten cognitive decline by interfering with the delicately orchestrated synchrony of oscillatory activities implicated in sleep-related memory consolidation. Therefore, we scrutinized the literature for mechanisms that might promote sleep-related epileptic activity in AD and, possibly dementia onset in epilepsy, and we also aimed to determine to what degree and through which processes such events might alter the progression of AD. Finally, we discuss the implications for patient care and try to identify a common basis for methodological considerations for future research and clinical practice.
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Affiliation(s)
- Anna B. Szabo
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, France
- Centre de Recherche Cerveau & Cognition (CerCo), UMR 5549, CNRS-UPS, Toulouse, France
- *Correspondence: Anna B. Szabo
| | - Benjamin Cretin
- Clinical Neuropsychology Unit, Neurology Department, CM2R (Memory Resource and Research Centre), University Hospital of Strasbourg, Strasbourg, France
- CNRS, ICube Laboratory, UMR 7357 and FMTS (Fédération de Médecine Translationnelle de Strasbourg), Team IMIS, University of Strasbourg, Strasbourg, France
- CMRR d'Alsace, Service de Neurologie des Hôpitaux Universitaires de Strasbourg, Pôle Tête et Cou, Strasbourg, France
| | - Fleur Gérard
- Centre de Recherche Cerveau & Cognition (CerCo), UMR 5549, CNRS-UPS, Toulouse, France
- Neurology Department, Hôpital Purpan Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Jonathan Curot
- Centre de Recherche Cerveau & Cognition (CerCo), UMR 5549, CNRS-UPS, Toulouse, France
- Neurology Department, Hôpital Purpan Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Emmanuel J. Barbeau
- Centre de Recherche Cerveau & Cognition (CerCo), UMR 5549, CNRS-UPS, Toulouse, France
| | - Jérémie Pariente
- Neurology Department, Hôpital Purpan Centre Hospitalier Universitaire de Toulouse, Toulouse, France
- Toulouse NeuroImaging Center (ToNIC), INSERM-University of Toulouse Paul Sabatier, Toulouse, France
| | - Lionel Dahan
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Luc Valton
- Centre de Recherche Cerveau & Cognition (CerCo), UMR 5549, CNRS-UPS, Toulouse, France
- Neurology Department, Hôpital Purpan Centre Hospitalier Universitaire de Toulouse, Toulouse, France
- Luc Valton
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30
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Das R, Luczak A. Epileptic seizures and link to memory processes. AIMS Neurosci 2022; 9:114-127. [PMID: 35434278 PMCID: PMC8941196 DOI: 10.3934/neuroscience.2022007] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/17/2022] [Accepted: 03/01/2022] [Indexed: 12/02/2022] Open
Abstract
Epileptogenesis is a complex and not well understood phenomenon. Here, we explore the hypothesis that epileptogenesis could be "hijacking" normal memory processes, and how this hypothesis may provide new directions for epilepsy treatment. First, we review similarities between the hypersynchronous circuits observed in epilepsy and memory consolidation processes involved in strengthening neuronal connections. Next, we describe the kindling model of seizures and its relation to long-term potentiation model of synaptic plasticity. We also examine how the strengthening of epileptic circuits is facilitated during the physiological slow wave sleep, similarly as episodic memories. Furthermore, we present studies showing that specific memories can directly trigger reflex seizures. The neuronal hypersynchrony in early stages of Alzheimer's disease, and the use of anti-epileptic drugs to improve the cognitive symptoms in this disease also suggests a connection between memory systems and epilepsy. Given the commonalities between memory processes and epilepsy, we propose that therapies for memory disorders might provide new avenues for treatment of epileptic patients.
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Affiliation(s)
- Ritwik Das
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
| | - Artur Luczak
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
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31
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Harutyunyan A, Jones NC, Kwan P, Anderson A. Network Preservation Analysis Reveals Dysregulated Synaptic Modules and Regulatory Hubs Shared Between Alzheimer’s Disease and Temporal Lobe Epilepsy. Front Genet 2022; 13:821343. [PMID: 35309145 PMCID: PMC8926077 DOI: 10.3389/fgene.2022.821343] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 01/20/2022] [Indexed: 01/08/2023] Open
Abstract
Background: There is increased prevalence of epilepsy in patients with Alzheimer’s disease (AD). Although shared pathological and clinical features have been identified, the underlying pathophysiology and cause-effect relationships are poorly understood. We aimed to identify commonly dysregulated groups of genes between these two disorders. Methods: Using publicly available transcriptomic data from hippocampal tissue of patients with temporal lobe epilepsy (TLE), late onset AD and non-AD controls, we constructed gene coexpression networks representing all three states. We then employed network preservation statistics to compare the density and connectivity-based preservation of functional gene modules between TLE, AD and controls and used the difference in significance scores as a surrogate quantifier of module preservation. Results: The majority (>90%) of functional gene modules were highly preserved between all coexpression networks, however several modules identified in the TLE network showed various degrees of preservation in the AD network compared to that of control. Of note, two synaptic signalling-associated modules and two metabolic modules showed substantial gain of preservation, while myelination and immune system-associated modules showed significant loss of preservation. The genes SCN3B and EPHA4 were identified as central regulatory hubs of the highly preserved synaptic signalling-associated module. GABRB3 and SCN2A were identified as central regulatory hubs of a smaller neurogenesis-associated module, which was enriched for multiple epileptic activity and seizure-related human phenotype ontologies. Conclusion: We conclude that these hubs and their downstream signalling pathways are common modulators of synaptic activity in the setting of AD and TLE, and may play a critical role in epileptogenesis in AD.
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Affiliation(s)
- Anna Harutyunyan
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, VIC, Australia
| | - Nigel C. Jones
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, VIC, Australia
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Neurology, The Alfred Hospital, Melbourne, VIC, Australia
| | - Patrick Kwan
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, VIC, Australia
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Neurology, The Alfred Hospital, Melbourne, VIC, Australia
| | - Alison Anderson
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, VIC, Australia
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
- *Correspondence: Alison Anderson,
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32
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Leparulo A, Bisio M, Redolfi N, Pozzan T, Vassanelli S, Fasolato C. Accelerated Aging Characterizes the Early Stage of Alzheimer's Disease. Cells 2022; 11:238. [PMID: 35053352 PMCID: PMC8774248 DOI: 10.3390/cells11020238] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/12/2021] [Accepted: 01/08/2022] [Indexed: 02/01/2023] Open
Abstract
For Alzheimer's disease (AD), aging is the main risk factor, but whether cognitive impairments due to aging resemble early AD deficits is not yet defined. When working with mouse models of AD, the situation is just as complicated, because only a few studies track the progression of the disease at different ages, and most ignore how the aging process affects control mice. In this work, we addressed this problem by comparing the aging process of PS2APP (AD) and wild-type (WT) mice at the level of spontaneous brain electrical activity under anesthesia. Using local field potential recordings, obtained with a linear probe that traverses the posterior parietal cortex and the entire hippocampus, we analyzed how multiple electrical parameters are modified by aging in AD and WT mice. With this approach, we highlighted AD specific features that appear in young AD mice prior to plaque deposition or that are delayed at 12 and 16 months of age. Furthermore, we identified aging characteristics present in WT mice but also occurring prematurely in young AD mice. In short, we found that reduction in the relative power of slow oscillations (SO) and Low/High power imbalance are linked to an AD phenotype at its onset. The loss of SO connectivity and cortico-hippocampal coupling between SO and higher frequencies as well as the increase in UP-state and burst durations are found in young AD and old WT mice. We show evidence that the aging process is accelerated by the mutant PS2 itself and discuss such changes in relation to amyloidosis and gliosis.
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Affiliation(s)
- Alessandro Leparulo
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35131 Padua, Italy; (A.L.); (M.B.); (N.R.); (T.P.)
| | - Marta Bisio
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35131 Padua, Italy; (A.L.); (M.B.); (N.R.); (T.P.)
| | - Nelly Redolfi
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35131 Padua, Italy; (A.L.); (M.B.); (N.R.); (T.P.)
| | - Tullio Pozzan
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35131 Padua, Italy; (A.L.); (M.B.); (N.R.); (T.P.)
- Neuroscience Institute-Italian National Research Council (CNR), Via U. Bassi 58/B, 35131 Padua, Italy
- Venetian Institute of Molecular Medicine (VIMM), Via G. Orus 2B, 35129 Padua, Italy
| | - Stefano Vassanelli
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35131 Padua, Italy; (A.L.); (M.B.); (N.R.); (T.P.)
- Padua Neuroscience Center (PNC), University of Padua, Via G. Orus 2B, 35129 Padua, Italy
| | - Cristina Fasolato
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35131 Padua, Italy; (A.L.); (M.B.); (N.R.); (T.P.)
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33
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Somogyi A, Wolf E. Increased Signal Delays and Unaltered Synaptic Input Pattern Recognition in Layer III Neocortical Pyramidal Neurons of the rTg4510 Mouse Model of Tauopathy: A Computer Simulation Study With Passive Membrane. Front Neurosci 2021; 15:721773. [PMID: 34733131 PMCID: PMC8558261 DOI: 10.3389/fnins.2021.721773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 09/22/2021] [Indexed: 11/13/2022] Open
Abstract
Abnormal tau proteins are involved in pathology of many neurodegenerative disorders. Transgenic rTg4510 mice express high levels of human tau protein with P301L mutation linked to chromosome 17 that has been associated with frontotemporal dementia with parkinsonism. By 9 months of age, these mice recapitulate key features of human tauopathies, including presence of hyperphosphorylated tau and neurofibrillary tangles (NFTs) in brain tissue, atrophy and loss of neurons and synapses, and hyperexcitability of neurons, as well as cognitive deficiencies. We investigated effects of such human mutant tau protein on neuronal membrane, subthreshold dendritic signaling, and synaptic input pattern recognition/discrimination in layer III frontal transgenic (TG) pyramidal neurons of 9-month-old rTg4510 mice and compared these characteristics to those of wild-type (WT) pyramidal neurons from age-matched control mice. Passive segmental cable models of WT and TG neurons were set up in the NEURON simulator by using three-dimensionally reconstructed morphology and electrophysiological data of these cells. Our computer simulations predict leakage resistance and capacitance of neuronal membrane to be unaffected by the mutant tau protein. Computer models of TG neurons showed only modest alterations in distance dependence of somatopetal voltage and current transfers along dendrites and in rise times and half-widths of somatic Excitatory Postsynaptic Potential (EPSPs) relative to WT control. In contrast, a consistent and statistically significant slowdown was detected in the speed of simulated subthreshold dendritic signal propagation in all regions of the dendritic surface of mutant neurons. Predictors of synaptic input pattern recognition/discrimination remained unaltered in model TG neurons. This suggests that tau pathology is primarily associated with failures/loss in synaptic connections rather than with altered intraneuronal synaptic integration in neurons of affected networks.
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Affiliation(s)
- Attila Somogyi
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Department of Emergency Medicine, University of Debrecen, Debrecen, Hungary
| | - Ervin Wolf
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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34
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Wirt RA, Crew LA, Ortiz AA, McNeela AM, Flores E, Kinney JW, Hyman JM. Altered theta rhythm and hippocampal-cortical interactions underlie working memory deficits in a hyperglycemia risk factor model of Alzheimer's disease. Commun Biol 2021; 4:1036. [PMID: 34480097 PMCID: PMC8417282 DOI: 10.1038/s42003-021-02558-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 07/28/2021] [Indexed: 01/04/2023] Open
Abstract
Diabetes mellitus is a metabolic disease associated with dysregulated glucose and insulin levels and an increased risk of developing Alzheimer’s disease (AD) later in life. It is thought that chronic hyperglycemia leads to neuroinflammation and tau hyperphosphorylation in the hippocampus leading to cognitive decline, but effects on hippocampal network activity are unknown. A sustained hyperglycemic state was induced in otherwise healthy animals and subjects were then tested on a spatial delayed alternation task while recording from the hippocampus and anterior cingulate cortex (ACC). Hyperglycemic animals performed worse on long delay trials and had multiple electrophysiological differences throughout the task. We found increased delta power and decreased theta power in the hippocampus, which led to altered theta/delta ratios at the end of the delay period. Cross frequency coupling was significantly higher in multiple bands and delay period hippocampus-ACC theta coherence was elevated, revealing hypersynchrony. The highest coherence values appeared long delays on error trials for STZ animals, the opposite of what was observed in controls, where lower delay period coherence was associated with errors. Consistent with previous investigations, we found increases in phosphorylated tau in STZ animals’ hippocampus and cortex, which might account for the observed oscillatory and cognitive changes. To investigate the effects of chronic hyperglycemia on hippocampal network activity Wirt et al induced sustained hyperglycemia in rats and tested them in a spatial delayed alternation task while recording from the hippocampus and anterior cingulate cortex. They demonstrated that hyperglycemia impaired task performance and altered theta rhythm as well as increasing tau phosphorylation, which suggest there is potentially a direct link between chronic hyperglycemia and Alzheimer’s disease.
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Affiliation(s)
- Ryan A Wirt
- Interdisciplinary Program in Neuroscience, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Lauren A Crew
- Interdisciplinary Program in Neuroscience, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Andrew A Ortiz
- Interdisciplinary Program in Neuroscience, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Adam M McNeela
- Interdisciplinary Program in Neuroscience, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Emmanuel Flores
- Interdisciplinary Program in Neuroscience, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Jefferson W Kinney
- Department of Brain Health, School of Integrated Health Sciences, University of Nevada, Las Vegas, NV, USA
| | - James M Hyman
- Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV, USA.
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35
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Fernandez‐Perez EJ, Muñoz B, Bascuñan DA, Peters C, Riffo‐Lepe NO, Espinoza MP, Morgan PJ, Filippi C, Bourboulou R, Sengupta U, Kayed R, Epsztein J, Aguayo LG. Synaptic dysregulation and hyperexcitability induced by intracellular amyloid beta oligomers. Aging Cell 2021; 20:e13455. [PMID: 34409748 PMCID: PMC8441418 DOI: 10.1111/acel.13455] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/21/2021] [Accepted: 08/05/2021] [Indexed: 12/19/2022] Open
Abstract
Intracellular amyloid beta oligomer (iAβo) accumulation and neuronal hyperexcitability are two crucial events at early stages of Alzheimer's disease (AD). However, to date, no mechanism linking iAβo with an increase in neuronal excitability has been reported. Here, the effects of human AD brain-derived (h-iAβo) and synthetic (iAβo) peptides on synaptic currents and action potential firing were investigated in hippocampal neurons. Starting from 500 pM, iAβo rapidly increased the frequency of synaptic currents and higher concentrations potentiated the AMPA receptor-mediated current. Both effects were PKC-dependent. Parallel recordings of synaptic currents and nitric oxide (NO)-associated fluorescence showed that the increased frequency, related to pre-synaptic release, was dependent on a NO-mediated retrograde signaling. Moreover, increased synchronization in NO production was also observed in neurons neighboring those dialyzed with iAβo, indicating that iAβo can increase network excitability at a distance. Current-clamp recordings suggested that iAβo increased neuronal excitability via AMPA-driven synaptic activity without altering membrane intrinsic properties. These results strongly indicate that iAβo causes functional spreading of hyperexcitability through a synaptic-driven mechanism and offers an important neuropathological significance to intracellular species in the initial stages of AD, which include brain hyperexcitability and seizures.
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Affiliation(s)
| | - Braulio Muñoz
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Denisse A. Bascuñan
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Christian Peters
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Nicolas O. Riffo‐Lepe
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Maria P. Espinoza
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
| | - Peter J. Morgan
- Institute of Neurobiology of the Mediterranean Sea (INMED)Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille UniversitéMarseilleFrance
| | - Caroline Filippi
- Institute of Neurobiology of the Mediterranean Sea (INMED)Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille UniversitéMarseilleFrance
| | - Romain Bourboulou
- Institute of Neurobiology of the Mediterranean Sea (INMED)Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille UniversitéMarseilleFrance
| | - Urmi Sengupta
- Mitchell Center for Neurodegenerative DiseasesUniversity of Texas Medical BranchGalvestonTexasUSA
- Department of Neurology, Neuroscience and Cell BiologyUniversity of Texas Medical BranchGalvestonTexasUSA
| | - Rakez Kayed
- Mitchell Center for Neurodegenerative DiseasesUniversity of Texas Medical BranchGalvestonTexasUSA
- Department of Neurology, Neuroscience and Cell BiologyUniversity of Texas Medical BranchGalvestonTexasUSA
| | - Jérôme Epsztein
- Institute of Neurobiology of the Mediterranean Sea (INMED)Institut National de la Santé et de la Recherche Médicale (INSERM) U901, Aix-Marseille UniversitéMarseilleFrance
| | - Luis G. Aguayo
- Laboratory of NeurophysiologyDepartment of PhysiologyUniversidad de ConcepciónConcepciónChile
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36
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Tok S, Ahnaou A, Drinkenburg W. Functional Neurophysiological Biomarkers of Early-Stage Alzheimer's Disease: A Perspective of Network Hyperexcitability in Disease Progression. J Alzheimers Dis 2021; 88:809-836. [PMID: 34420957 PMCID: PMC9484128 DOI: 10.3233/jad-210397] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Network hyperexcitability (NH) has recently been suggested as a potential neurophysiological indicator of Alzheimer’s disease (AD), as new, more accurate biomarkers of AD are sought. NH has generated interest as a potential indicator of certain stages in the disease trajectory and even as a disease mechanism by which network dysfunction could be modulated. NH has been demonstrated in several animal models of AD pathology and multiple lines of evidence point to the existence of NH in patients with AD, strongly supporting the physiological and clinical relevance of this readout. Several hypotheses have been put forward to explain the prevalence of NH in animal models through neurophysiological, biochemical, and imaging techniques. However, some of these hypotheses have been built on animal models with limitations and caveats that may have derived NH through other mechanisms or mechanisms without translational validity to sporadic AD patients, potentially leading to an erroneous conclusion of the underlying cause of NH occurring in patients with AD. In this review, we discuss the substantiation for NH in animal models of AD pathology and in human patients, as well as some of the hypotheses considering recently developed animal models that challenge existing hypotheses and mechanisms of NH. In addition, we provide a preclinical perspective on how the development of animal models incorporating AD-specific NH could provide physiologically relevant translational experimental data that may potentially aid the discovery and development of novel therapies for AD.
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Affiliation(s)
- Sean Tok
- Department of Neuroscience, Janssen Research & Development, Janssen Pharmaceutica NV, Beerse, Belgium.,Groningen Institute for Evolutionary Life Sciences, Faculty of Science and Engineering, University of Groningen, The Netherlands
| | - Abdallah Ahnaou
- Department of Neuroscience, Janssen Research & Development, Janssen Pharmaceutica NV, Beerse, Belgium
| | - Wilhelmus Drinkenburg
- Department of Neuroscience, Janssen Research & Development, Janssen Pharmaceutica NV, Beerse, Belgium.,Groningen Institute for Evolutionary Life Sciences, Faculty of Science and Engineering, University of Groningen, The Netherlands
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37
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Ahnaou A, Drinkenburg WHIM. Sleep, neuronal hyperexcitability, inflammation and neurodegeneration: Does early chronic short sleep trigger and is it the key to overcoming Alzheimer's disease? Neurosci Biobehav Rev 2021; 129:157-179. [PMID: 34214513 DOI: 10.1016/j.neubiorev.2021.06.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 05/13/2021] [Accepted: 06/25/2021] [Indexed: 01/13/2023]
Abstract
Evidence links neuroinflammation to Alzheimer's disease (AD); however, its exact contribution to the onset and progression of the disease is poorly understood. Symptoms of AD can be seen as the tip of an iceberg, consisting of a neuropathological build-up in the brain of extracellular amyloid-β (Aβ) plaques and intraneuronal hyperphosphorylated aggregates of Tau (pTau), which are thought to stem from an imbalance between its production and clearance resulting in loss of synaptic health and dysfunctional cortical connectivity. The glymphatic drainage system, which is particularly active during sleep, plays a key role in the clearance of proteinopathies. Poor sleep can cause hyperexcitability and promote Aβ and tau pathology leading to systemic inflammation. The early neuronal hyperexcitability of γ-aminobutyric acid (GABA)-ergic inhibitory interneurons and impaired inhibitory control of cortical pyramidal neurons lie at the crossroads of excitatory/inhibitory imbalance and inflammation. We outline, with a prospective framework, a possible vicious spiral linking early chronic short sleep, neuronal hyperexcitability, inflammation and neurodegeneration. Understanding the early predictors of AD, through an integrative approach, may hold promise for reducing attrition in the late stages of neuroprotective drug development.
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Affiliation(s)
- A Ahnaou
- Dept. of Neuroscience Discovery, Janssen Research & Development, A Division of Janssen Pharmaceutica NV, Turnhoutseweg 30, Beerse, B-2340, Belgium.
| | - W H I M Drinkenburg
- Dept. of Neuroscience Discovery, Janssen Research & Development, A Division of Janssen Pharmaceutica NV, Turnhoutseweg 30, Beerse, B-2340, Belgium
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38
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Jin N, Babiloni C, Drinkenburg WH, Hajós M, Nygaard HB, Tanila H. Recommendations for Preclinical Testing of Treatments Against Alzheimer's Disease-Related Epileptiform Spikes in Transgenic Rodent Models. J Alzheimers Dis 2021; 88:849-865. [PMID: 34092642 DOI: 10.3233/jad-210209] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Recent evidence suggests that about 30%of patients with mild to moderate Alzheimer's disease (AD) without a known diagnosis of epilepsy may display epileptiform spikes during electroencephalographic (EEG) recordings. These abnormal discharges occur predominantly during sleep and may be associated with accelerated disease progression. Subclinical spikes may represent a relevant target for clinical drug interventions, and there is a clear unmet need for preclinical testing of novel disease modifying agents in suitable animal models. Transgenic rodent models of AD pathology exhibit various forms of epileptiform EEG activity related to the abnormal levels of amyloid species in the brain. Among them, large-amplitude cortical and hippocampal EEG spikes in mouse and rat AD models may be reminiscent of the subclinical epileptiform EEG spikes recorded in some AD patients. This article reports the recommendations of a multidisciplinary panel of experts on optimal EEG markers and experimental designs to measure and report epileptiform activities and their response to symptomatic and disease-modifying drugs in transgenic AD model rodents. These recommendations may harmonize future preclinical EEG studies in the drug discovery research and may increase the comparability of experimental outcomes and their translational clinical value.
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Affiliation(s)
- Nanxiang Jin
- A. I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
| | - Claudio Babiloni
- Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Rome, Italy.,Hospital San Raffaele Cassino, Cassino (FR), Italy
| | - Wilhelmus H Drinkenburg
- Janssen Research & Development, Janssen Pharmaceutica NV, Beerse, Belgium.,Groningen Institute for Evolutionary Life Sciences, University of Groningen, The Netherlands
| | - Mihály Hajós
- Cognito Therapeutics, Cambridge, MA, USA.,Yale University School of Medicine, New Haven, CT, USA
| | - Haakon B Nygaard
- Division of Neurology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Heikki Tanila
- A. I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland
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39
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Dejakaisaya H, Kwan P, Jones NC. Astrocyte and glutamate involvement in the pathogenesis of epilepsy in Alzheimer's disease. Epilepsia 2021; 62:1485-1493. [PMID: 33971019 DOI: 10.1111/epi.16918] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) can increase the risk of epilepsy by up to 10-fold compared to healthy age-matched controls. However, the pathological mechanisms that underlie this increased risk are poorly understood. Because disruption in brain glutamate homeostasis has been implicated in both AD and epilepsy, this might play a mechanistic role in the pathogenesis of epilepsy in AD. Prior to the formation of amyloid beta (Aβ) plaques, the brain can undergo pathological changes as a result of increased production of amyloid precursor protein (APP) and Aβ oligomers. Impairments in the glutamate uptake ability of astrocytes due to astrogliosis are hypothesized to be an early event occurring before Aβ plaque formation. Astrogliosis may increase the susceptibility to epileptogenesis of the brain via accumulation of extracellular glutamate and resulting excitotoxicity. Here we hypothesize that Aβ oligomers and proinflammatory cytokines can cause astrogliosis and accumulation of extracellular glutamate, which then contribute to the pathogenesis of epilepsy in AD. In this review article, we consider the evidence supporting a potential role of dysfunction of the glutamate-glutamine cycle and the astrocyte in the pathogenesis of epilepsy in AD.
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Affiliation(s)
- Hattapark Dejakaisaya
- Department of Neuroscience, Central Clinical School, The Alfred Hospital, Monash University, Melbourne, Vic., Australia.,Faculty of Medicine and Public Health, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Patrick Kwan
- Department of Neuroscience, Central Clinical School, The Alfred Hospital, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Vic., Australia
| | - Nigel C Jones
- Department of Neuroscience, Central Clinical School, The Alfred Hospital, Monash University, Melbourne, Vic., Australia.,Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Vic., Australia
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40
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McGlynn E, Nabaei V, Ren E, Galeote‐Checa G, Das R, Curia G, Heidari H. The Future of Neuroscience: Flexible and Wireless Implantable Neural Electronics. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2002693. [PMID: 34026431 PMCID: PMC8132070 DOI: 10.1002/advs.202002693] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 01/15/2021] [Indexed: 05/04/2023]
Abstract
Neurological diseases are a prevalent cause of global mortality and are of growing concern when considering an ageing global population. Traditional treatments are accompanied by serious side effects including repeated treatment sessions, invasive surgeries, or infections. For example, in the case of deep brain stimulation, large, stiff, and battery powered neural probes recruit thousands of neurons with each pulse, and can invoke a vigorous immune response. This paper presents challenges in engineering and neuroscience in developing miniaturized and biointegrated alternatives, in the form of microelectrode probes. Progress in design and topology of neural implants has shifted the goal post toward highly specific recording and stimulation, targeting small groups of neurons and reducing the foreign body response with biomimetic design principles. Implantable device design recommendations, fabrication techniques, and clinical evaluation of the impact flexible, integrated probes will have on the treatment of neurological disorders are provided in this report. The choice of biocompatible material dictates fabrication techniques as novel methods reduce the complexity of manufacture. Wireless power, the final hurdle to truly implantable neural interfaces, is discussed. These aspects are the driving force behind continued research: significant breakthroughs in any one of these areas will revolutionize the treatment of neurological disorders.
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Affiliation(s)
- Eve McGlynn
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Vahid Nabaei
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Elisa Ren
- Laboratory of Experimental Electroencephalography and NeurophysiologyDepartment of BiomedicalMetabolic and Neural SciencesUniversity of Modena and Reggio EmiliaModena41125Italy
| | - Gabriel Galeote‐Checa
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Rupam Das
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
| | - Giulia Curia
- Laboratory of Experimental Electroencephalography and NeurophysiologyDepartment of BiomedicalMetabolic and Neural SciencesUniversity of Modena and Reggio EmiliaModena41125Italy
| | - Hadi Heidari
- Microelectronics LabJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUnited Kingdom
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41
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Neuronal Network Excitability in Alzheimer's Disease: The Puzzle of Similar versus Divergent Roles of Amyloid β and Tau. eNeuro 2021; 8:ENEURO.0418-20.2020. [PMID: 33741601 PMCID: PMC8174042 DOI: 10.1523/eneuro.0418-20.2020] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/02/2020] [Accepted: 12/18/2020] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD) is the most frequent neurodegenerative disorder that commonly causes dementia in the elderly. Recent evidence indicates that network abnormalities, including hypersynchrony, altered oscillatory rhythmic activity, interneuron dysfunction, and synaptic depression, may be key mediators of cognitive decline in AD. In this review, we discuss characteristics of neuronal network excitability in AD, and the role of Aβ and tau in the induction of network hyperexcitability. Many patients harboring genetic mutations that lead to increased Aβ production suffer from seizures and epilepsy before the development of plaques. Similarly, pathologic accumulation of hyperphosphorylated tau has been associated with hyperexcitability in the hippocampus. We present common and divergent roles of tau and Aβ on neuronal hyperexcitability in AD, and hypotheses that could serve as a template for future experiments.
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Lamoureux L, Marottoli FM, Tseng KY, Tai LM. APOE4 Promotes Tonic-Clonic Seizures, an Effect Modified by Familial Alzheimer's Disease Mutations. Front Cell Dev Biol 2021; 9:656521. [PMID: 33796539 PMCID: PMC8007905 DOI: 10.3389/fcell.2021.656521] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/23/2021] [Indexed: 11/13/2022] Open
Abstract
Seizures are emerging as a common symptom in Alzheimer's disease (AD) patients, often attributed to high levels of amyloid β (Aβ). However, the extent that AD disease risk factors modulate seizure activity in aging and AD-relevant contexts is unclear. APOE4 is the greatest genetic risk factor for AD and has been linked to seizures independent of AD and Aβ. The goal of the present study was to evaluate the role of APOE genotype in modulating seizures in the absence and presence of high Aβ levels in vivo. To achieve this goal, we utilized EFAD mice, which express human APOE3 or APOE4 in the absence (EFAD-) or presence (EFAD+) of familial AD mutations that result in Aβ overproduction. When quantified during cage change day, we found that unlike APOE3, APOE4 is associated with tonic-clonic seizures. Interestingly, there were lower tonic-clonic seizures in E4FAD+ mice compared to E4FAD- mice. Restraint handing and auditory stimuli failed to recapitulate the tonic-clonic phenotype in EFAD mice that express APOE4. However, after chemical-induction with pentylenetetrazole, there was a higher incidence of tonic-clonic seizures with APOE4 compared to APOE3. Interestingly, the distribution of seizures to the tonic-clonic phenotype was higher with FAD mutations. These data support that APOE4 is associated with higher tonic-clonic seizures in vivo, and that FAD mutations impact tonic-clonic seizures in a paradigm dependent manner.
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Affiliation(s)
- Lorissa Lamoureux
- Biological Resources Laboratory, University of Illinois at Chicago, Chicago, IL, United States
| | - Felecia M Marottoli
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Kuei Y Tseng
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
| | - Leon M Tai
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL, United States
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Sosulina L, Mittag M, Geis HR, Hoffmann K, Klyubin I, Qi Y, Steffen J, Friedrichs D, Henneberg N, Fuhrmann F, Justus D, Keppler K, Cuello AC, Rowan MJ, Fuhrmann M, Remy S. Hippocampal hyperactivity in a rat model of Alzheimer's disease. J Neurochem 2021; 157:2128-2144. [PMID: 33583024 DOI: 10.1111/jnc.15323] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 01/19/2021] [Accepted: 01/31/2021] [Indexed: 12/21/2022]
Abstract
Neuronal network dysfunction is a hallmark of Alzheimer's disease (AD). However, the underlying pathomechanisms remain unknown. We analyzed the hippocampal micronetwork in transgenic McGill-R-Thy1-APP rats (APPtg) at the beginning of extracellular amyloid beta (Aβ) deposition. We established two-photon Ca2+ -imaging in vivo in the hippocampus of rats and found hyperactivity of CA1 neurons. Patch-clamp recordings in brain slices in vitro revealed increased neuronal input resistance and prolonged action potential width in CA1 pyramidal neurons. We did neither observe changes in synaptic inhibition, nor in excitation. Our data support the view that increased intrinsic excitability of CA1 neurons may precede inhibitory dysfunction at an early stage of Aβ-deposition and disease progression.
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Affiliation(s)
- Liudmila Sosulina
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Department of Cellular Neuroscience, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Manuel Mittag
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Hans-Rüdiger Geis
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Kerstin Hoffmann
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Igor Klyubin
- Department of Pharmacology and Therapeutics, Trinity College, Dublin, Ireland
| | - Yingjie Qi
- Department of Pharmacology and Therapeutics, Trinity College, Dublin, Ireland
| | - Julia Steffen
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Detlef Friedrichs
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Niklas Henneberg
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Falko Fuhrmann
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Daniel Justus
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Kevin Keppler
- Light Microscopy Facility, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - A Claudio Cuello
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Michael J Rowan
- Department of Pharmacology and Therapeutics, Trinity College, Dublin, Ireland
| | - Martin Fuhrmann
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Stefan Remy
- Neuronal Networks Group, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Department of Cellular Neuroscience, Leibniz Institute for Neurobiology, Magdeburg, Germany
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Alcantara-Gonzalez D, Chartampila E, Criscuolo C, Scharfman HE. Early changes in synaptic and intrinsic properties of dentate gyrus granule cells in a mouse model of Alzheimer's disease neuropathology and atypical effects of the cholinergic antagonist atropine. Neurobiol Dis 2021; 152:105274. [PMID: 33484828 DOI: 10.1016/j.nbd.2021.105274] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 01/09/2021] [Accepted: 01/16/2021] [Indexed: 12/19/2022] Open
Abstract
It has been reported that hyperexcitability occurs in a subset of patients with Alzheimer's disease (AD) and hyperexcitability could contribute to the disease. Several studies have suggested that the hippocampal dentate gyrus (DG) may be an important area where hyperexcitability occurs. Therefore, we tested the hypothesis that the principal DG cell type, granule cells (GCs), would exhibit changes at the single-cell level which would be consistent with hyperexcitability and might help explain it. We used the Tg2576 mouse, where it has been shown that hyperexcitability is robust at 2-3 months of age. GCs from 2 to 3-month-old Tg2576 mice were compared to age-matched wild type (WT) mice. Effects of muscarinic cholinergic antagonism were tested because previously we found that Tg2576 mice exhibited hyperexcitability in vivo that was reduced by the muscarinic cholinergic antagonist atropine, counter to the dogma that in AD one needs to boost cholinergic function. The results showed that GCs from Tg2576 mice exhibited increased frequency of spontaneous excitatory postsynaptic potentials/currents (sEPSP/Cs) and reduced frequency of spontaneous inhibitory synaptic events (sIPSCs) relative to WT, increasing the excitation:inhibition (E:I) ratio. There was an inward NMDA receptor-dependent current that we defined here as a novel synaptic current (nsC) in Tg2576 mice because it was very weak in WT mice. Intrinsic properties were distinct in Tg2576 GCs relative to WT. In summary, GCs of the Tg2576 mouse exhibit early electrophysiological alterations that are consistent with increased synaptic excitation, reduced inhibition, and muscarinic cholinergic dysregulation. The data support previous suggestions that the DG contributes to hyperexcitability and there is cholinergic dysfunction early in life in AD mouse models.
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Affiliation(s)
- David Alcantara-Gonzalez
- Center for Dementia Research, the Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
| | - Elissavet Chartampila
- Center for Dementia Research, the Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
| | - Chiara Criscuolo
- Center for Dementia Research, the Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA.
| | - Helen E Scharfman
- Center for Dementia Research, the Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Child & Adolescent Psychiatry, Neuroscience & Physiology, and Psychiatry, New York University Langone Health, New York, NY 10016, USA; Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA.
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Unravelling the Role of Glycogen Synthase Kinase-3 in Alzheimer's Disease-Related Epileptic Seizures. Int J Mol Sci 2020; 21:ijms21103676. [PMID: 32456185 PMCID: PMC7279454 DOI: 10.3390/ijms21103676] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/20/2020] [Accepted: 05/20/2020] [Indexed: 12/21/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia. An increasing body of evidence describes an elevated incidence of epilepsy in patients with AD, and many transgenic animal models of AD also exhibit seizures and susceptibility to epilepsy. However, the biological mechanisms that underlie the occurrence of seizure or increased susceptibility to seizures in AD is unknown. Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase that regulates various cellular signaling pathways, and plays a crucial role in the pathogenesis of AD. It has been suggested that GSK-3 might be a key factor that drives epileptogenesis in AD by interacting with the pathological hallmarks of AD, amyloid precursor protein (APP) and tau. Furthermore, seizures may also contribute to the progression of AD through GSK-3. In this way, GSK-3 might be involved in initiating a vicious cycle between AD and seizures. This review aims to summarise the possible role of GSK-3 in the link between AD and seizures. Understanding the role of GSK-3 in AD-associated seizures and epilepsy may help researchers develop new therapeutic approach that can manage seizure and epilepsy in AD patients as well as decelerate the progression of AD.
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Rizzello E, Middei S, Marchetti C. Synaptic Correlates of Anterograde Amnesia and Intact Retrograde Memory in a Mouse Model of Alzheimer’s Disease. Curr Alzheimer Res 2020; 17:259-268. [DOI: 10.2174/1567205017666200224122113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 12/30/2019] [Accepted: 02/12/2020] [Indexed: 01/08/2023]
Abstract
Background:
Clinical evidence indicates that patients affected by Alzheimer's Disease (AD)
fail to form new memories although their memories for old events are intact. This amnesic pattern depends
on the selective vulnerability to AD-neurodegeneration of the hippocampus, the brain region that
sustains the formation of new memories, while cortical regions that store remote memories are spared.
Objective:
To identify the cellular mechanisms underlying impaired recent memories and intact remote
memories in a mouse model of AD.
Method:
Glutamatergic synaptic currents were recorded by patch-clamp in acute hippocampal and
anterior Cingulate Cortical (aCC) slices of AD-like Tg2576 mice and Wild-type (Wt) littermates subjected
to the Contextual Fear Conditioning (CFC) task or in naïve conditions.
Results:
Glutamatergic synaptic currents were recorded by patch-clamp in acute hippocampal and
anterior Cingulate Cortical (aCC) slices of AD-like Tg2576 mice and Wild-type (Wt) littermates subjected
to the Contextual Fear Conditioning (CFC) task or in naïve conditions.
Conclusion:
Our data suggest that in the early AD stages synaptic plasticity of CA1 synapses, crucial
to form new memories, is lost, while plasticity of aCC synapses is intact and contributes to the persistence
of long-term memories.
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Affiliation(s)
- Emanuela Rizzello
- European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Via Regina Elena 295, 00161, Rome, Italy
| | - Silvia Middei
- Consiglio Nazionale delle Ricerche (CNR), Institute of Biochemistry and Cell Biology, Via E. Ramarini 32, 00015 Monterotondo, Rome, Italy
| | - Cristina Marchetti
- European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Via Regina Elena 295, 00161, Rome, Italy
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Abe Y, Ikegawa N, Yoshida K, Muramatsu K, Hattori S, Kawai K, Murakami M, Tanaka T, Goda W, Goto M, Yamamoto T, Hashimoto T, Yamada K, Shibata T, Misawa H, Mimura M, Tanaka KF, Miyakawa T, Iwatsubo T, Hata JI, Niikura T, Yasui M. Behavioral and electrophysiological evidence for a neuroprotective role of aquaporin-4 in the 5xFAD transgenic mice model. Acta Neuropathol Commun 2020; 8:67. [PMID: 32398151 PMCID: PMC7218576 DOI: 10.1186/s40478-020-00936-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 04/21/2020] [Indexed: 12/19/2022] Open
Abstract
Aquaporin-4 (AQP4) has been suggested to be involved in the pathogenesis of neurodegenerative diseases including Alzheimer's disease (AD), which may be due to the modulation of neuroinflammation or the impairment of interstitial fluid bulk flow system in the central nervous system. Here, we show an age-dependent impairment of several behavioral outcomes in 5xFAD AQP4 null mice. Twenty-four-hour video recordings and computational analyses of their movement revealed that the nighttime motion of AQP4-deficient 5xFAD mice was progressively reduced between 20 and 36 weeks of age, with a sharp deterioration occurring between 30 and 32 weeks. This reduction in nighttime motion was accompanied by motor dysfunction and epileptiform neuronal activities, demonstrated by increased abnormal spikes by electroencephalography. In addition, all AQP4-deficient 5xFAD mice exhibited convulsions at least once during the period of the analysis. Interestingly, despite such obvious phenotypes, parenchymal amyloid β (Aβ) deposition, reactive astrocytosis, and activated microgliosis surrounding amyloid plaques were unchanged in the AQP4-deficient 5xFAD mice relative to 5xFAD mice. Taken together, our data indicate that AQP4 deficiency greatly accelerates an age-dependent deterioration of neuronal function in 5xFAD mice associated with epileptiform neuronal activity without significantly altering Aβ deposition or neuroinflammation in this mouse model. We therefore propose that there exists another pathophysiological phase in AD which follows amyloid plaque deposition and neuroinflammation and is sensitive to AQP4 deficiency.
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Amyloid β-Induced Upregulation of Na v1.6 Underlies Neuronal Hyperactivity in Tg2576 Alzheimer's Disease Mouse Model. Sci Rep 2019; 9:13592. [PMID: 31537873 PMCID: PMC6753212 DOI: 10.1038/s41598-019-50018-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 07/31/2019] [Indexed: 12/19/2022] Open
Abstract
Hyperexcitability and alterations in neuronal networks contribute to cognitive impairment in Alzheimer’s Disease (AD). Voltage-gated sodium channels (NaV), which are crucial for regulating neuronal excitability, have been implicated in AD-related hippocampal hyperactivity and higher incidence of spontaneous non-convulsive seizures. Here, we show by using primary hippocampal neurons exposed to amyloid-β1–42 (Aβ1–42) oligomers and from Tg2576 mouse embryos, that the selective upregulation of NaV1.6 subtype contributes to membrane depolarization and to the increase of spike frequency, thereby resulting in neuronal hyperexcitability. Interestingly, we also found that NaV1.6 overexpression is responsible for the aberrant neuronal activity observed in hippocampal slices from 3-month-old Tg2576 mice. These findings identify the NaV1.6 channels as a determinant of the hippocampal neuronal hyperexcitability induced by Aβ1–42 oligomers. The selective blockade of NaV1.6 overexpression and/or hyperactivity might therefore offer a new potential therapeutic approach to counteract early hippocampal hyperexcitability and subsequent cognitive deficits in the early stages of AD.
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Pignataro A, Meli G, Pagano R, Fontebasso V, Battistella R, Conforto G, Ammassari-Teule M, Middei S. Activity-Induced Amyloid-β Oligomers Drive Compensatory Synaptic Rearrangements in Brain Circuits Controlling Memory of Presymptomatic Alzheimer's Disease Mice. Biol Psychiatry 2019; 86:185-195. [PMID: 30528194 DOI: 10.1016/j.biopsych.2018.10.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 10/02/2018] [Accepted: 10/22/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND A consistent proportion of individuals at risk for Alzheimer's disease show intact cognition regardless of the extensive accumulation of amyloid-β (Aβ) peptide in their brain. Several pieces of evidence indicate that overactivation of brain regions negative for Aβ can compensate for the underactivation of Aβ-positive ones to preserve cognition, but the underlying synaptic changes are still unexplored. METHODS Using Golgi staining, we investigate how dendritic spines rearrange following contextual fear conditioning (CFC) in the hippocampus and amygdala of presymptomatic Tg2576 mice, a genetic model for Aβ accumulation. A molecular biology approach combined with intrahippocampal injection of a γ-secretase inhibitor evaluates the impact of Aβ fluctuations on spine rearrangements. RESULTS Encoding of CFC increases Aβ oligomerization in the hippocampus but not in the amygdala of Tg2576 mice. The presence of Aβ oligomers predicts vulnerability to network dysfunctions, as low c-Fos activation and spine maturation are detected in the hippocampus of Tg2576 mice upon recall of CFC memory. Rather, enhanced c-Fos activation and new spines are evident in the amygdala of Tg2576 mice compared with wild-type control mice. Preventing Aβ increase in the hippocampus of Tg2576 mice restores CFC-associated spine changes to wild-type levels in both the hippocampus and amygdala. CONCLUSIONS Our study provides the first evidence of neural compensation consisting of enhanced synaptic activity in brain regions spared by Aβ load. Furthermore, it unravels an activity-mediated feedback loop through which neuronal activation during CFC encoding favors Aβ oligomerization in the hippocampus and prevents synaptic rearrangements in this region.
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Affiliation(s)
- Annabella Pignataro
- Laboratory of Psychobiology, Department of Experimental Neurology, Santa Lucia Foundation, Rome, Italy; Institute of Cell Biology and Neurobiology, National Research Council, Rome, Italy
| | - Giovanni Meli
- European Brain Research Institute-Fondazione Rita Levi Montalcini, Rome, Italy.
| | - Roberto Pagano
- Department of Molecular and Cellular Neurobiology Laboratory of Molecular Basis of Behavior, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Veronica Fontebasso
- Department of Pharmacology & Toxicology and Center for Chemistry and Biomedicine, University of Innsbruck, Innsbruck, Austria
| | - Roberta Battistella
- Department of Experimental Biomedical Sciences, Lund University, Lund, Sweden
| | - Giulia Conforto
- Laboratory of Psychobiology, Department of Experimental Neurology, Santa Lucia Foundation, Rome, Italy
| | - Martine Ammassari-Teule
- Laboratory of Psychobiology, Department of Experimental Neurology, Santa Lucia Foundation, Rome, Italy; Institute of Cell Biology and Neurobiology, National Research Council, Rome, Italy
| | - Silvia Middei
- Institute of Cell Biology and Neurobiology, National Research Council, Rome, Italy.
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Vico Varela E, Etter G, Williams S. Excitatory-inhibitory imbalance in Alzheimer's disease and therapeutic significance. Neurobiol Dis 2019; 127:605-615. [DOI: 10.1016/j.nbd.2019.04.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 04/08/2019] [Accepted: 04/12/2019] [Indexed: 11/29/2022] Open
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