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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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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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Jeong M, Jang JH, Oh SJ, Park J, Lee J, Hwang S, Oh YS. Maladaptation of dentate gyrus mossy cells mediates contextual discrimination deficit after traumatic stress. Cell Rep 2024; 43:114000. [PMID: 38527063 DOI: 10.1016/j.celrep.2024.114000] [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: 02/02/2023] [Revised: 02/15/2024] [Accepted: 03/10/2024] [Indexed: 03/27/2024] Open
Abstract
Fear overgeneralization is a maladaptive response to traumatic stress that is associated with the inability to discriminate between threat and safety contexts, a hallmark feature of post-traumatic stress disorder (PTSD). However, the neural mechanisms underlying this deficit remain unclear. Here, we show that traumatic stress exposure impairs contextual discrimination between threat and safety contexts in the learned helplessness (LH) model. Mossy cells (MCs) in the dorsal hippocampus are suppressed in response to traumatic stress. Bidirectional manipulation of MC activity in the LH model reveals that MC inhibition is causally linked to impaired contextual discrimination. Mechanistically, MC inhibition increases the number of active granule cells in a given context, significantly overlapping context-specific ensembles. Our study demonstrates that maladaptive inhibition of MCs after traumatic stress is a substantial mechanism underlying fear overgeneralization with contextual discrimination deficit, suggesting a potential therapeutic target for cognitive symptoms of PTSD.
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Affiliation(s)
- Minseok Jeong
- Department of Brain Sciences, Daegu-Gyeongbuk Institute of Science and Technology, Hyeonpung-eup, Dalseong-gun, Daegu 42988, Republic of Korea
| | - Jin-Hyeok Jang
- Department of Brain Sciences, Daegu-Gyeongbuk Institute of Science and Technology, Hyeonpung-eup, Dalseong-gun, Daegu 42988, Republic of Korea
| | - Seo-Jin Oh
- Department of Brain Sciences, Daegu-Gyeongbuk Institute of Science and Technology, Hyeonpung-eup, Dalseong-gun, Daegu 42988, Republic of Korea
| | - Jeongrak Park
- Department of Brain Sciences, Daegu-Gyeongbuk Institute of Science and Technology, Hyeonpung-eup, Dalseong-gun, Daegu 42988, Republic of Korea
| | - Junseop Lee
- Department of Brain Sciences, Daegu-Gyeongbuk Institute of Science and Technology, Hyeonpung-eup, Dalseong-gun, Daegu 42988, Republic of Korea
| | - Sehyeon Hwang
- Department of Brain Sciences, Daegu-Gyeongbuk Institute of Science and Technology, Hyeonpung-eup, Dalseong-gun, Daegu 42988, Republic of Korea
| | - Yong-Seok Oh
- Department of Brain Sciences, Daegu-Gyeongbuk Institute of Science and Technology, Hyeonpung-eup, Dalseong-gun, Daegu 42988, Republic of Korea; Emotion, Cognition & Behavior Research Group, Korea Brain Research Institute, 61 Cheomdan-ro, Daegu 41062, Republic of Korea.
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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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Piquet R, Faugère A, Parkes SL. Contribution of dorsal versus ventral hippocampus to the hierarchical modulation of goal-directed actions in rats. Eur J Neurosci 2023; 58:3737-3750. [PMID: 37697949 DOI: 10.1111/ejn.16143] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/21/2023] [Accepted: 08/28/2023] [Indexed: 09/13/2023]
Abstract
Adaptive behaviour often necessitates that animals learn about events in a manner that is specific to a particular context or environment. These hierarchical organisations allow the animal to decide which action is the most appropriate when faced with ambiguous or conflicting possibilities. This study examined the role of hippocampus in enabling animals to use the context to guide action selection. We used a hierarchical instrumental outcome devaluation task in which male rats learn that the context provides information about the unique action-outcome relations that are in effect. We first confirmed that rats encode and use hierarchical context-(action-outcome) relations. We then show that chemogenetic inhibition of ventral hippocampus impairs both the encoding and retrieval of these associations, while inhibition of dorsal hippocampus impairs only the retrieval. Importantly, neither dorsal nor ventral hippocampus was required for goal-directed behaviour per se as these impairments only emerged when rats were forced to use the context to identify the current action-outcome relationships. These findings are discussed with respect to the role of the hippocampus and its broader circuitry in the contextual modulation of goal-directed behaviour and the importance of hierarchical associations in flexible behaviour.
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Affiliation(s)
- Robin Piquet
- University of Bordeaux, CNRS, INCIA, UMR 5287, Bordeaux, France
| | | | - Shauna L Parkes
- University of Bordeaux, CNRS, INCIA, UMR 5287, Bordeaux, France
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Borzello M, Ramirez S, Treves A, Lee I, Scharfman H, Stark C, Knierim JJ, Rangel LM. Assessments of dentate gyrus function: discoveries and debates. Nat Rev Neurosci 2023; 24:502-517. [PMID: 37316588 PMCID: PMC10529488 DOI: 10.1038/s41583-023-00710-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2023] [Indexed: 06/16/2023]
Abstract
There has been considerable speculation regarding the function of the dentate gyrus (DG) - a subregion of the mammalian hippocampus - in learning and memory. In this Perspective article, we compare leading theories of DG function. We note that these theories all critically rely on the generation of distinct patterns of activity in the region to signal differences between experiences and to reduce interference between memories. However, these theories are divided by the roles they attribute to the DG during learning and recall and by the contributions they ascribe to specific inputs or cell types within the DG. These differences influence the information that the DG is thought to impart to downstream structures. We work towards a holistic view of the role of DG in learning and memory by first developing three critical questions to foster a dialogue between the leading theories. We then evaluate the extent to which previous studies address our questions, highlight remaining areas of conflict, and suggest future experiments to bridge these theories.
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Affiliation(s)
- Mia Borzello
- Department of Cognitive Science, University of California, San Diego, La Jolla, CA, USA
| | - Steve Ramirez
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
| | | | - Inah Lee
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, South Korea
| | - Helen Scharfman
- Departments of Child and Adolescent Psychiatry, Neuroscience and Physiology and Psychiatry and the Neuroscience Institute, New York University Langone Health, New York, NY, USA
- The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA
| | - Craig Stark
- Department of Neurobiology and Behaviour, University of California, Irvine, Irvine, CA, USA
| | - James J Knierim
- Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | - Lara M Rangel
- Department of Cognitive Science, University of California, San Diego, La Jolla, CA, USA.
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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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Leal Santos S, Chen BK, Pereira GR, Pham V, Denny CA. Propranolol Administration Modulates Neural Activity in the Hippocampal Hilus During Fear Retrieval. Front Behav Neurosci 2022; 16:919831. [PMID: 35874651 PMCID: PMC9301278 DOI: 10.3389/fnbeh.2022.919831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/13/2022] [Indexed: 11/23/2022] Open
Abstract
Altered fear learning is a strong behavioral component of anxiety disorders such as post-traumatic stress disorder (PTSD). Recent efforts have attempted to combine exposure therapies with drugs that target fear memory retrieval and memory reconsolidation, in order to improve treatment efficacy. The noradrenergic (NA) signaling system is of particular interest, due to its role in regulating the stress response and its involvement in fear and learning processes. Importantly, propranolol (P), a non-selective β-adrenergic antagonist, has shown the potential in decreasing exaggerated fear in both humans and animal models. In a previous study, we utilized an activity-dependent tagging murine model to determine the neural mechanisms by which propranolol attenuates learned fear. We found that propranolol acutely decreased memory trace reactivation specifically in the dorsal dentate gyrus (dDG), but not in CA3 or CA1. Here, we extended our previous study by investigating whether propranolol additionally altered activity in the hilus, a polymorphic layer that consists of neurons, mossy cells, and GABAergic interneurons. We found that propranolol acutely reduced overall hilar activity in both the dorsal and ventral hilus. Moreover, we report that propranolol significantly altered the activity of parvalbumin (PV)+ cells in the ventral (vDG), but not dorsal DG (dDG). Together, these results suggest that a β-adrenergic blockade may affect the activity of excitatory and inhibitory cell types in the hilar layer of the DG, and that these alterations may contribute to manipulating fear memory traces.
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Affiliation(s)
- Sofia Leal Santos
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY, United States
- Division of Systems Neuroscience, Research Foundation for Mental Hygiene, Inc. (RFMH)/New York State Psychiatric Institute (NYSPI), New York, NY, United States
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- Instituto de Investigação em Ciências da Vida e da Saúde (ICVS)/3Bs - PT Government Associate Laboratory, Guimarães, Portugal
| | - Briana K. Chen
- Neurobiology and Behavior (NB&B) Graduate Program, Columbia University, New York, NY, United States
| | - Guilherme R. Pereira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- Instituto de Investigação em Ciências da Vida e da Saúde (ICVS)/3Bs - PT Government Associate Laboratory, Guimarães, Portugal
| | - Vananh Pham
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY, United States
- Division of Systems Neuroscience, Research Foundation for Mental Hygiene, Inc. (RFMH)/New York State Psychiatric Institute (NYSPI), New York, NY, United States
| | - Christine A. Denny
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY, United States
- Division of Systems Neuroscience, Research Foundation for Mental Hygiene, Inc. (RFMH)/New York State Psychiatric Institute (NYSPI), New York, NY, United States
- *Correspondence: Christine A. Denny,
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Abdulmajeed WI, Wang KY, Wu JW, Ajibola MI, Cheng IHJ, Lien CC. Connectivity and synaptic features of hilar mossy cells and their effects on granule cell activity along the hippocampal longitudinal axis. J Physiol 2022; 600:3355-3381. [PMID: 35671148 DOI: 10.1113/jp282804] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/01/2022] [Indexed: 11/08/2022] Open
Abstract
The hippocampus is an elongated brain structure which runs along a ventral-to-dorsal axis in rodents, corresponding to the anterior-to-posterior axis in humans. A glutamatergic cell type in the dentate gyrus (DG), the mossy cells (MCs), establishes extensive excitatory collateral connections with the DG principal cells, the granule cells (GCs), and inhibitory interneurons in both hippocampal hemispheres along the longitudinal axis. Although coupling of two physically separated GC populations via long-axis projecting MCs is instrumental for information processing, the connectivity and synaptic features of MCs along the longitudinal axis are poorly defined. Here, using channelrhodopsin-2 assisted circuit mapping, we showed that MC excitation results in a low synaptic excitation-inhibition (E/I) balance in the intralamellar (local) GCs, but a high synaptic E/I balance in the translamellar (distant) ones. In agreement with the differential E/I balance along the ventrodorsal axis, activation of MCs either enhances or suppresses the local GC response to the cortical input, but primarily promotes the distant GC activation. Moreover, activation of MCs enhances the spike timing precision of the local GCs, but not that of the distant ones. Collectively, these findings suggest that MCs differentially regulate the local and distant GC activity through distinct synaptic mechanisms. KEY POINTS: Hippocampal mossy cell (MC) pathways differentially regulate granule cell (GC) activity along the longitudinal axis. MCs mediate a low excitation-inhibition balance in intralamellar (local) GCs, but a high excitation-inhibition balance in translamellar (distant) GCs. MCs enhance the spiking precision of local GCs, but not distant GCs. MCs either promote or suppress local GC activity, but primarily promote distant GC activation.
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Affiliation(s)
- Wahab Imam Abdulmajeed
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, Academia Sinica, Taipei, Taiwan.,Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, University of Ilorin, Ilorin, Nigeria
| | - Kai-Yi Wang
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Jei-Wei Wu
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Musa Iyiola Ajibola
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, Academia Sinica, Taipei, Taiwan.,Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Irene Han-Juo Cheng
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, Academia Sinica, Taipei, Taiwan.,Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Cheng-Chang Lien
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, Academia Sinica, Taipei, Taiwan.,Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
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11
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GoodSmith D, Kim SH, Puliyadi V, Ming GL, Song H, Knierim JJ, Christian KM. Flexible encoding of objects and space in single cells of the dentate gyrus. Curr Biol 2022; 32:1088-1101.e5. [PMID: 35108522 PMCID: PMC8930604 DOI: 10.1016/j.cub.2022.01.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 11/12/2021] [Accepted: 01/10/2022] [Indexed: 01/05/2023]
Abstract
The hippocampus is involved in the formation of memories that require associations among stimuli to construct representations of space and the items and events within that space. Neurons in the dentate gyrus (DG), an initial input region of the hippocampus, have robust spatial tuning, but it is unclear how nonspatial information may be integrated with spatial activity in this region. We recorded from the DG of 21 adult mice as they foraged for food in an environment that contained discrete objects. We found DG cells with multiple firing fields at a fixed distance and direction from objects (landmark vector cells) and cells that exhibited localized changes in spatial firing when objects in the environment were manipulated. By classifying recorded DG cells into putative dentate granule cells and mossy cells, we examined how the addition or displacement of objects affected the spatial firing of these DG cell types. Object-related activity was detected in a significant proportion of mossy cells. Although few granule cells with responses to object manipulations were recorded, likely because of the sparse nature of granule cell firing, there was generally no significant difference in the proportion of granule cells and mossy cells with object responses. When mice explored a second environment with the same objects, DG spatial maps completely reorganized, and a different subset of cells responded to object manipulations. Together, these data reveal the capacity of DG cells to detect small changes in the environment while preserving a stable spatial representation of the overall context.
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Affiliation(s)
- Douglas GoodSmith
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 733 N Broadway, Baltimore, MD 21205, USA; Department of Neurobiology and Neuroscience Institute, University of Chicago, 5801 S Ellis Avenue, Chicago, IL 60637, USA
| | - Sang Hoon Kim
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Vyash Puliyadi
- Department of Psychological and Brain Sciences, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA; Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA
| | - Guo-Li Ming
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Hongjun Song
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA; The Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA.
| | - James J Knierim
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 733 N Broadway, Baltimore, MD 21205, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, 733 N Broadway, Baltimore, MD 21205, USA.
| | - Kimberly M Christian
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA.
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12
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Ma Y, Bayguinov PO, McMahon SM, Scharfman HE, Jackson MB. Direct synaptic excitation between hilar mossy cells revealed with a targeted voltage sensor. Hippocampus 2021; 31:1215-1232. [PMID: 34478219 DOI: 10.1002/hipo.23386] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 08/09/2021] [Accepted: 08/21/2021] [Indexed: 12/18/2022]
Abstract
The dentate gyrus not only gates the flow of information into the hippocampus, it also integrates and processes this information. Mossy cells (MCs) are a major type of excitatory neuron strategically located in the hilus of the dentate gyrus where they can contribute to this processing through networks of synapses with inhibitory neurons and dentate granule cells. Some prior work has suggested that MCs can form excitatory synapses with other MCs, but the role of these synapses in the network activity of the dentate gyrus has received little attention. Here, we investigated synaptic inputs to MCs in mouse hippocampal slices using a genetically encoded hybrid voltage sensor (hVOS) targeted to MCs by Cre-lox technology. This enabled optical recording of voltage changes from multiple MCs simultaneously. Stimulating granule cells and CA3 pyramidal cells activated well-established inputs to MCs and elicited synaptic responses as expected. However, the weak blockade of MC responses to granule cell layer stimulation by DCG-IV raised the possibility of another source of excitation. To evaluate synapses between MCs as this source, single MCs were stimulated focally. Stimulation of one MC above its action potential threshold evoked depolarizing responses in neighboring MCs that depended on glutamate receptors. Short latency responses of MCs to other MCs did not depend on release from granule cell axons. However, granule cells did contribute to the longer latency responses of MCs to stimulation of other MCs. Thus, MCs transmit their activity to other MCs both through direct synaptic coupling and through polysynaptic coupling with dentate granule cells. MC-MC synapses can redistribute information entering the dentate gyrus and thus shape and modulate the electrical activity underlying hippocampal functions such as navigation and memory, as well as excessive excitation during seizures.
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Affiliation(s)
- Yihe Ma
- Department of Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Peter O Bayguinov
- Washington University Center for Cellular Imaging, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Shane M McMahon
- Department of Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Helen E Scharfman
- New York University Langone Health and the Nathan Kline Institute for Psychiatric Research, Orangeburg, New Jersey, USA
| | - Meyer B Jackson
- Department of Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Modeling intrahippocampal effects of anterior hippocampal hyperactivity relevant to schizophrenia using chemogenetic excitation of long axis-projecting mossy cells in the mouse dentate gyrus. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2021; 1:101-111. [PMID: 34414387 PMCID: PMC8372626 DOI: 10.1016/j.bpsgos.2021.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Background The anterior hippocampus of individuals with early psychosis or schizophrenia is hyperactive, as is the ventral hippocampus in many rodent models for schizophrenia risk. Mossy cells (MCs) of the ventral dentate gyrus (DG) densely project in the hippocampal long axis, targeting both dorsal DG granule cells and inhibitory interneurons. MCs are responsive to stimulation throughout hippocampal subfields and thus may be suited to detect hyperactivity in areas where it originates such as CA1. Here, we tested the hypothesis that hyperactivation of ventral MCs activates dorsal DG granule cells to influence dorsal hippocampal function. Methods In CD-1 mice, we targeted dorsal DG-projecting ventral MCs using an adeno-associated virus intersectional strategy. In vivo fiber photometry recording of ventral MCs was performed during exploratory behaviors. We used excitatory chemogenetic constructs to test the effects of ventral MC hyperactivation on long-term spatial memory during an object location memory task. Results Photometry revealed that ventral MCs were activated during exploratory rearing. Ventral MCs made functional monosynaptic inputs to dorsal DG granule cells, and chemogenetic activation of ventral MCs modestly increased activity of dorsal DG granule cells measured by c-Fos. Finally, chemogenetic activation of ventral MCs during the training phase of an object location memory task impaired test performance 24 hours later, without effects on locomotion or object exploration. Conclusions These data suggest that ventral MC activation can directly excite dorsal granule cells and interfere with dorsal DG function, supporting future study of their in vivo activity in animal models for schizophrenia featuring ventral hyperactivity.
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14
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Fredes F, Shigemoto R. The role of hippocampal mossy cells in novelty detection. Neurobiol Learn Mem 2021; 183:107486. [PMID: 34214666 DOI: 10.1016/j.nlm.2021.107486] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 04/29/2021] [Accepted: 06/24/2021] [Indexed: 10/21/2022]
Abstract
At the encounter with a novel environment, contextual memory formation is greatly enhanced, accompanied with increased arousal and active exploration. Although this phenomenon has been widely observed in animal and human daily life, how the novelty in the environment is detected and contributes to contextual memory formation has lately started to be unveiled. The hippocampus has been studied for many decades for its largely known roles in encoding spatial memory, and a growing body of evidence indicates a differential involvement of dorsal and ventral hippocampal divisions in novelty detection. In this brief review article, we discuss the recent findings of the role of mossy cells in the ventral hippocampal moiety in novelty detection and put them in perspective with other novelty-related pathways in the hippocampus. We propose a mechanism for novelty-driven memory acquisition in the dentate gyrus by the direct projection of ventral mossy cells to dorsal dentate granule cells. By this projection, the ventral hippocampus sends novelty signals to the dorsal hippocampus, opening a gate for memory encoding in dentate granule cells based on information coming from the entorhinal cortex. We conclude that, contrary to the presently accepted functional independence, the dorsal and ventral hippocampi cooperate to link the novelty and contextual information, and this dorso-ventral interaction is crucial for the novelty-dependent memory formation.
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Affiliation(s)
- Felipe Fredes
- Department of Biomedicine, Aarhus University, Ole Worms Ale 6, Building 1182, 8000 Aarhus C, Denmark
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria (IST Austria), Am Campus 1, Klosterneuburg 3400, Austria
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15
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Botterill JJ, Gerencer KJ, Vinod KY, Alcantara‐Gonzalez D, Scharfman HE. Dorsal and ventral mossy cells differ in their axonal projections throughout the dentate gyrus of the mouse hippocampus. Hippocampus 2021; 31:522-539. [PMID: 33600026 PMCID: PMC8247909 DOI: 10.1002/hipo.23314] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 01/24/2021] [Accepted: 01/30/2021] [Indexed: 11/14/2022]
Abstract
Glutamatergic hilar mossy cells (MCs) have axons that terminate both near and far from their cell body but stay within the DG, making synapses primarily in the molecular layer. The long-range axons are considered the primary projection, and extend throughout the DG ipsilateral to the soma, and project to the contralateral DG. The specificity of MC axons for the inner molecular layer (IML) has been considered to be a key characteristic of the DG. In the present study, we made the surprising finding that dorsal MC axons are an exception to this rule. We used two mouse lines that allow for Cre-dependent viral labeling of MCs and their axons: dopamine receptor D2 (Drd2-Cre) and calcitonin receptor-like receptor (Crlr-Cre). A single viral injection into the dorsal DG to label dorsal MCs resulted in labeling of MC axons in both the IML and middle molecular layer (MML). Interestingly, this broad termination of dorsal MC axons occurred throughout the septotemporal DG. In contrast, long-range axons of ventral MCs terminated in the IML, consistent with the literature. Taken together, these results suggest that dorsal and ventral MCs differ significantly in their axonal projections. Since MC projections in the ML are thought to terminate primarily on GCs, the results suggest a dorsal-ventral difference in MC activation of GCs. The surprising difference in dorsal and ventral MC projections should therefore be considered when evaluating dorsal-ventral differences in DG function.
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Affiliation(s)
- Justin J. Botterill
- Center for Dementia ResearchThe Nathan Kline Institute for Psychiatric ResearchOrangeburgNew YorkUSA
| | - Kathleen J. Gerencer
- Center for Dementia ResearchThe Nathan Kline Institute for Psychiatric ResearchOrangeburgNew YorkUSA
| | - K. Yaragudri Vinod
- Department of Analytical PsychopharmacologyThe Nathan Kline Institute for Psychiatric ResearchOrangeburgNew YorkUSA
- Emotional Brain InstituteThe Nathan Kline Institute for Psychiatric ResearchOrangeburgNew YorkUSA
- Department of Child & Adolescent Psychiatry, Neuroscience & Physiology and Psychiatry and the New York University Neuroscience InstituteNew York University Langone HealthNew YorkNew YorkUSA
| | - David Alcantara‐Gonzalez
- Center for Dementia ResearchThe Nathan Kline Institute for Psychiatric ResearchOrangeburgNew YorkUSA
| | - Helen E. Scharfman
- Center for Dementia ResearchThe Nathan Kline Institute for Psychiatric ResearchOrangeburgNew YorkUSA
- Department of Child & Adolescent Psychiatry, Neuroscience & Physiology and Psychiatry and the New York University Neuroscience InstituteNew York University Langone HealthNew YorkNew YorkUSA
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16
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Houser CR, Peng Z, Wei X, Huang CS, Mody I. Mossy Cells in the Dorsal and Ventral Dentate Gyrus Differ in Their Patterns of Axonal Projections. J Neurosci 2021; 41:991-1004. [PMID: 33268544 PMCID: PMC7880284 DOI: 10.1523/jneurosci.2455-20.2020] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/08/2020] [Accepted: 11/20/2020] [Indexed: 01/22/2023] Open
Abstract
Mossy cells (MCs) of the dentate gyrus (DG) are a major group of excitatory hilar neurons that are important for regulating activity of dentate granule cells. MCs are particularly intriguing because of their extensive longitudinal connections within the DG. It has generally been assumed that MCs in the dorsal and ventral DG have similar patterns of termination in the inner one-third of the dentate molecular layer. Here, we demonstrate that axonal projections of MCs in these two regions are considerably different. MCs in dorsal and ventral regions were labeled selectively with Cre-dependent eYFP or mCherry, using two transgenic mouse lines (including both sexes) that express Cre-recombinase in MCs. At four to six weeks following unilateral labeling of MCs in the ventral DG, a dense band of fibers was present in the inner one-fourth of the molecular layer and extended bilaterally throughout the rostral-caudal extent of the DG, replicating the expected distribution of MC axons. In contrast, following labeling of MCs in the dorsal DG, the projections were more diffusely distributed. At the level of transfection, fibers were present in the inner molecular layer, but they progressively expanded into the middle molecular layer and, most ventrally, formed a distinct band in this region. Optical stimulation of these caudal fibers expressing ChR2 demonstrated robust EPSCs in ipsilateral granule cells and enhanced the effects of perforant path stimulation in the ventral DG. These findings suggest that MCs in the dorsal and ventral DG differ in the distribution of their axonal projections and possibly their function.SIGNIFICANCE STATEMENT Mossy cells (MCs), a major cell type in the hilus of the dentate gyrus (DG), are unique in providing extensive longitudinal and commissural projections throughout the DG. Although it has been assumed that all MCs have similar patterns of termination in the inner molecular layer of the DG, we discovered that the axonal projections of dorsal and ventral MCs differ. While ventral MC projections exhibit the classical pattern, with dense innervation in the inner molecular layer, dorsal MCs have a more diffuse distribution and expand into the middle molecular layer where they overlap and interact with innervation from the perforant path. These distinct locations and patterns of axonal projections suggest that dorsal and ventral MCs may have different functional roles.
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Affiliation(s)
- Carolyn R Houser
- Department of Neurobiology
- Brain Research Institute, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
| | | | | | | | - Istvan Mody
- Department of Neurology
- Brain Research Institute, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California 90095
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17
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Bidirectional Regulation of Cognitive and Anxiety-like Behaviors by Dentate Gyrus Mossy Cells in Male and Female Mice. J Neurosci 2021; 41:2475-2495. [PMID: 33472828 DOI: 10.1523/jneurosci.1724-20.2021] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 12/04/2020] [Accepted: 01/04/2021] [Indexed: 02/08/2023] Open
Abstract
The dentate gyrus (DG) of the hippocampus is important for cognition and behavior. However, the circuits underlying these functions are unclear. DG mossy cells (MCs) are potentially important because of their excitatory synapses on the primary cell type, granule cells (GCs). However, MCs also activate GABAergic neurons, which inhibit GCs. We used viral delivery of designer receptors exclusively activated by designer drugs (DREADDs) in mice to implement a gain- and loss-of-function study of MCs in diverse behaviors. Using this approach, manipulations of MCs could bidirectionally regulate behavior. The results suggest that inhibiting MCs can reduce anxiety-like behavior and improve cognitive performance. However, not all cognitive or anxiety-related behaviors were influenced, suggesting specific roles of MCs in some, but not all, types of cognition and anxiety. Notably, several behaviors showed sex-specific effects, with females often showing more pronounced effects than the males. We also used the immediate early gene c-Fos to address whether DREADDs bidirectionally regulated MC or GC activity. We confirmed excitatory DREADDs increased MC c-Fos. However, there was no change in GC c-Fos, consistent with MC activation leading to GABAergic inhibition of GCs. In contrast, inhibitory DREADDs led to a large increase in GC c-Fos, consistent with a reduction in MC excitation of GABAergic neurons, and reduced inhibition of GCs. Together, these results suggest that MCs regulate anxiety and cognition in specific ways. We also raise the possibility that cognitive performance may be improved by reducing anxiety.SIGNIFICANCE STATEMENT The dentate gyrus (DG) has many important cognitive roles as well as being associated with affective behavior. This study addressed how a glutamatergic DG cell type called mossy cells (MCs) contributes to diverse behaviors, which is timely because it is known that MCs regulate the activity of the primary DG cell type, granule cells (GCs), but how MC activity influences behavior is unclear. We show, surprisingly, that activating MCs can lead to adverse behavioral outcomes, and inhibiting MCs have an opposite effect. Importantly, the results appeared to be task-dependent and showed that testing both sexes was important. Additional experiments indicated what MC and GC circuitry was involved. Together, the results suggest how MCs influence behaviors that involve the DG.
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18
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Fredes F, Silva MA, Koppensteiner P, Kobayashi K, Joesch M, Shigemoto R. Ventro-dorsal Hippocampal Pathway Gates Novelty-Induced Contextual Memory Formation. Curr Biol 2021; 31:25-38.e5. [PMID: 33065009 PMCID: PMC7808756 DOI: 10.1016/j.cub.2020.09.074] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 09/08/2020] [Accepted: 09/24/2020] [Indexed: 01/07/2023]
Abstract
Novelty facilitates memory formation and is detected by both the dorsal and ventral hippocampus. Although dentate granule cells (GCs) in the dorsal hippocampus are known to mediate the formation of novelty-induced contextual memories, the required pathways and mechanisms remain unclear. Here we demonstrate that a powerful excitatory pathway from mossy cells (MCs) in the ventral hippocampus to dorsal GCs is necessary and sufficient for driving dorsal GC activation in novel environment exploration. In vivo Ca2+ imaging in freely moving mice indicated that this pathway relays environmental novelty. Furthermore, manipulation of ventral MC activity bidirectionally regulates novelty-induced contextual memory acquisition. Our results show that ventral MC activity gates contextual memory formation through an intra-hippocampal interaction activated by environmental novelty.
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Affiliation(s)
- Felipe Fredes
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria; Department of Biomedicine, Aarhus University, Ole Worms Alle 6, Building 1182, 8000 Aarhus C, Denmark.
| | - Maria Alejandra Silva
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Peter Koppensteiner
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Kenta Kobayashi
- Section of Viral Vector Development, National Institute for Physiological Sciences, Myodaiji, Okazaki, Japan
| | - Maximilian Joesch
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria.
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19
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Botterill JJ, Lu YL, LaFrancois JJ, Bernstein HL, Alcantara-Gonzalez D, Jain S, Leary P, Scharfman HE. An Excitatory and Epileptogenic Effect of Dentate Gyrus Mossy Cells in a Mouse Model of Epilepsy. Cell Rep 2020; 29:2875-2889.e6. [PMID: 31775052 PMCID: PMC6905501 DOI: 10.1016/j.celrep.2019.10.100] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 09/25/2019] [Accepted: 10/24/2019] [Indexed: 12/20/2022] Open
Abstract
The sparse activity of hippocampal dentate gyrus (DG) granule cells (GCs) is thought to be critical for cognition and behavior, whereas excessive DG activity may contribute to disorders such as temporal lobe epilepsy (TLE). Glutamatergic mossy cells (MCs) of the DG are potentially critical to normal and pathological functions of the DG because they can regulate GC activity through innervation of GCs or indirectly through GABAergic neurons. Here, we test the hypothesis that MC excitation of GCs is normally weak, but under pathological conditions, MC excitation of GCs is dramatically strengthened. We show that selectively inhibiting MCs during severe seizures reduced manifestations of those seizures, hippocampal injury, and chronic epilepsy. In contrast, selectively activating MCs was pro-convulsant. Mechanistic in vitro studies using optogenetics further demonstrated the unanticipated ability of MC axons to excite GCs under pathological conditions. These results demonstrate an excitatory and epileptogenic effect of MCs in the DG.
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Affiliation(s)
- Justin J Botterill
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Yi-Ling Lu
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - John J LaFrancois
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Hannah L Bernstein
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Neuroscience & Physiology, New York University Langone Health, New York, NY 10016, USA
| | - David Alcantara-Gonzalez
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Swati Jain
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Paige Leary
- 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 Neuroscience & Physiology, New York University Langone Health, New York, NY 10016, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA.
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20
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Grovola MR, Paleologos N, Wofford KL, Harris JP, Browne KD, Johnson V, Duda JE, Wolf JA, Cullen DK. Mossy cell hypertrophy and synaptic changes in the hilus following mild diffuse traumatic brain injury in pigs. J Neuroinflammation 2020; 17:44. [PMID: 32005260 PMCID: PMC6993507 DOI: 10.1186/s12974-020-1720-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 01/19/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Each year in the USA, over 2.4 million people experience mild traumatic brain injury (TBI), which can induce long-term neurological deficits. The dentate gyrus of the hippocampus is notably susceptible to damage following TBI, as hilar mossy cell changes in particular may contribute to post-TBI dysfunction. Moreover, microglial activation after TBI may play a role in hippocampal circuit and/or synaptic remodeling; however, the potential effects of chronic microglial changes are currently unknown. The objective of the current study was to assess neuropathological and neuroinflammatory changes in subregions of the dentate gyrus at acute to chronic time points following mild TBI using an established model of closed-head rotational acceleration induced TBI in pigs. METHODS This study utilized archival tissue of pigs which were subjected to sham conditions or rapid head rotation in the coronal plane to generate mild TBI. A quantitative assessment of neuropathological changes in the hippocampus was performed via immunohistochemical labeling of whole coronal tissue sections at 3 days post-injury (DPI), 7 DPI, 30 DPI, and 1 year post-injury (YPI), with a focus on mossy cell atrophy and synaptic reorganization, in context with microglial alterations (e.g., density, proximity to mossy cells) in the dentate gyrus. RESULTS There were no changes in mossy cell density between sham and injured animals, indicating no frank loss of mossy cells at the mild injury level evaluated. However, we found significant mossy cell hypertrophy at 7 DPI and 30 DPI in anterior (> 16% increase in mean cell area at each time; p = < 0.001 each) and 30 DPI in posterior (8.3% increase; p = < 0.0001) hippocampus. We also found dramatic increases in synapsin staining around mossy cells at 7 DPI in both anterior (74.7% increase in synapsin labeling; p = < 0.0001) and posterior (82.7% increase; p = < 0.0001) hippocampus. Interestingly, these morphological and synaptic alterations correlated with a significant change in microglia in proximity to mossy cells at 7 DPI in anterior and at 30 DPI in the posterior hippocampus. For broader context, while we found that there were significant increases in microglia density in the granule cell layer at 30 DPI (anterior and posterior) and 1 YPI (posterior only) and in the molecular layer at 1 YPI (anterior only), we found no significant changes in overall microglial density in the hilus at any of the time points evaluated post-injury. CONCLUSIONS The alterations of mossy cell size and synaptic inputs paired with changes in microglia density around the cells demonstrate the susceptibility of hilar mossy cells after even mild TBI. This subtle hilar mossy cell pathology may play a role in aberrant hippocampal function post-TBI, although additional studies are needed to characterize potential physiological and cognitive alterations.
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Affiliation(s)
- Michael R Grovola
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, Philadelphia, PA, 19104, USA
| | - Nicholas Paleologos
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, Philadelphia, PA, 19104, USA
| | - Kathryn L Wofford
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, Philadelphia, PA, 19104, USA
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA
| | - James P Harris
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, Philadelphia, PA, 19104, USA
| | - Kevin D Browne
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, Philadelphia, PA, 19104, USA
| | - Victoria Johnson
- Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, Philadelphia, PA, 19104, USA
| | - John E Duda
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Parkinson's Disease Research, Education and Clinical Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - John A Wolf
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA
- Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, Philadelphia, PA, 19104, USA
| | - D Kacy Cullen
- Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, USA.
- Center for Brain Injury & Repair, Department of Neurosurgery, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, Philadelphia, PA, 19104, USA.
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, 105E Hayden Hall/3320 Smith Walk, Philadelphia, PA, 19104, USA.
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21
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Christian KM, Ming GL, Song H. Adult neurogenesis and the dentate gyrus: Predicting function from form. Behav Brain Res 2019; 379:112346. [PMID: 31722241 DOI: 10.1016/j.bbr.2019.112346] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/05/2019] [Accepted: 11/05/2019] [Indexed: 12/11/2022]
Abstract
Hypotheses about the functional properties of the dentate gyrus and adult dentate neurogenesis have been shaped by early observations of the anatomy of this region, mostly in rodents. This has led to the development of a few core propositions that have guided research over the past several years, including the predicted role of this region in pattern separation and the local transformation of inputs from the entorhinal cortex. We now have the opportunity to review these predictions and update these anatomical observations based on recently developed techniques that reveal the complex structure, connectivity, and dynamic properties of distinct cell populations in the dentate gyrus at a higher resolution. Cumulative evidence suggests that the dentate gyrus and adult-born granule cells play a role in some forms of behavioral discriminations, but there are still many unanswered questions about how the dentate gyrus processes information to support the disambiguation of stimuli.
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Affiliation(s)
- Kimberly M Christian
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, 19104, USA; Mahoney Institute for Neurosciences, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Guo-Li Ming
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, 19104, USA; Mahoney Institute for Neurosciences, University of Pennsylvania, Philadelphia, PA, 19104, USA; Department of Developmental and Cell Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA; Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, 19104, USA; Institute for Epigenetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hongjun Song
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, 19104, USA; Mahoney Institute for Neurosciences, University of Pennsylvania, Philadelphia, PA, 19104, USA; Department of Developmental and Cell Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA; Institute for Regenerative Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Institute for Epigenetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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22
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Bernstein HL, Lu YL, Botterill JJ, Scharfman HE. Novelty and Novel Objects Increase c-Fos Immunoreactivity in Mossy Cells in the Mouse Dentate Gyrus. Neural Plast 2019; 2019:1815371. [PMID: 31534449 PMCID: PMC6732597 DOI: 10.1155/2019/1815371] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/05/2019] [Indexed: 02/06/2023] Open
Abstract
The dentate gyrus (DG) and its primary cell type, the granule cell (GC), are thought to be critical to many cognitive functions. A major neuronal subtype of the DG is the hilar mossy cell (MC). MCs have been considered to play an important role in cognition, but in vivo studies to understand the activity of MCs during cognitive tasks are challenging because the experiments usually involve trauma to the overlying hippocampus or DG, which kills hilar neurons. In addition, restraint typically occurs, and MC activity is reduced by brief restraint stress. Social isolation often occurs and is potentially confounding. Therefore, we used c-fos protein expression to understand when MCs are active in vivo in socially housed adult C57BL/6 mice in their home cage. We focused on c-fos protein expression after animals explored novel objects, based on previous work which showed that MCs express c-fos protein readily in response to a novel housing location. Also, MCs are required for the training component of the novel object location task and novelty-encoding during a food-related task. GluR2/3 was used as a marker of MCs. The results showed that MC c-fos protein is greatly increased after exposure to novel objects, especially in ventral DG. We also found that novel objects produced higher c-fos levels than familiar objects. Interestingly, a small subset of neurons that did not express GluR2/3 also increased c-fos protein after novel object exposure. In contrast, GCs appeared relatively insensitive. The results support a growing appreciation of the role of the DG in novelty detection and novel object recognition, where hilar neurons and especially MCs are very sensitive.
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Affiliation(s)
- Hannah L. Bernstein
- The Nathan S. Kline Institute for Psychiatric Research, Center for Dementia Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
- Departments of Child and Adolescent Psychiatry, Neuroscience and Physiology, and Psychiatry, and the Neuroscience Institute, New York University Langone Health, 100 First Ave., New York, NY 10016, USA
| | - Yi-Ling Lu
- The Nathan S. Kline Institute for Psychiatric Research, Center for Dementia Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
- Departments of Child and Adolescent Psychiatry, Neuroscience and Physiology, and Psychiatry, and the Neuroscience Institute, New York University Langone Health, 100 First Ave., New York, NY 10016, USA
| | - Justin J. Botterill
- The Nathan S. Kline Institute for Psychiatric Research, Center for Dementia Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
- Departments of Child and Adolescent Psychiatry, Neuroscience and Physiology, and Psychiatry, and the Neuroscience Institute, New York University Langone Health, 100 First Ave., New York, NY 10016, USA
| | - Helen E. Scharfman
- The Nathan S. Kline Institute for Psychiatric Research, Center for Dementia Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
- Departments of Child and Adolescent Psychiatry, Neuroscience and Physiology, and Psychiatry, and the Neuroscience Institute, New York University Langone Health, 100 First Ave., New York, NY 10016, USA
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23
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Jung D, Kim S, Sariev A, Sharif F, Kim D, Royer S. Dentate granule and mossy cells exhibit distinct spatiotemporal responses to local change in a one-dimensional landscape of visual-tactile cues. Sci Rep 2019; 9:9545. [PMID: 31267019 PMCID: PMC6606600 DOI: 10.1038/s41598-019-45983-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 06/19/2019] [Indexed: 11/09/2022] Open
Abstract
The dentate gyrus (DG) is critical for detecting changes in environments; however, how granule cells (GCs) and mossy cells (MCs), the two excitatory cell types of the DG, respond to small changes in the object layout is unclear. Here, we recorded GCs and MCs, identified by spike feature and optogenetic tagging, as mice ran on a treadmill belt enriched with visual-tactile cues. We observed that fixing a new cue on the belt induced a reconfiguration of GC and MC spatial representations via the emergence, extinction and rate alteration of firing fields. For both GCs and MCs, the response was maximal near the cue and spread over the entire belt. However, compared to the GC response, the MC response was stronger and more immediate, peaked at a slightly earlier belt position, and exhibited a transient component reminiscent of neuromodulatory activity. A competitive neural network model reproduced the GC response contingent on both the introduction of new object-vector inputs and the reconfiguration of MC activity, the former being critical for spreading the GC response in locations distant from the cue. These findings suggest that GCs operate as a competitive network and that MCs precede GCs in detecting changes and help expand the range of GC pattern separation.
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Affiliation(s)
- Dajung Jung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
| | - Soyoun Kim
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
| | - Anvar Sariev
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea
| | - Farnaz Sharif
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea
| | - Daesoo Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Sebastien Royer
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea.
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology, Seoul, 02792, Republic of Korea.
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24
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Scharfman HE. Advances in understanding hilar mossy cells of the dentate gyrus. Cell Tissue Res 2018; 373:643-652. [PMID: 29222692 PMCID: PMC5993616 DOI: 10.1007/s00441-017-2750-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 11/21/2017] [Indexed: 02/01/2023]
Abstract
Hilar mossy cells (MCs) of the dentate gyrus (DG) distinguish the DG from other hippocampal subfields (CA1-3) because there are two glutamatergic cell types in the DG rather than one. Thus, in the DG, the main cell types include glutamatergic granule cells (GCs) and MCs, whereas in CA1-3, the only glutamatergic cell type is the pyramidal cell. In contrast to GCs, MCs are different in morphology, intrinsic electrophysiological properties, afferent input and axonal projections, so their function is likely to be very different from GCs. Why are MCs necessary to the DG? In past studies, the answer has been unclear because MCs not only excite GCs directly but also inhibit them disynaptically, by exciting GABAergic neurons that project to GCs. Results of new studies are discussed that shed light on this issue. These studies take advantage of recently available transgenic mice with Cre recombinase expression mostly in MCs and techniques such as optogenetics and DREADDs (designer receptors exclusively activated by designer drugs). The recent studies also address in vivo behavioral functions of MCs. Some of the results support past hypotheses whereas others suggest new conceptualizations of how the MCs contribute to DG circuitry and function. While substantial progess has been made, additional research is still needed to clarify the characteristics and functions of these unique cells.
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Affiliation(s)
- Helen E Scharfman
- Departments of Child & Adolescent Psychiatry, Neuroscience & Physiology, Psychiatry, and the New York University Neuroscience Institute, New York University Langone Medical Center, One Park Avenue, 7th floor, New York, NY, 10016, USA.
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Building 39, Orangeburg, NY, 10962, USA.
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25
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Kassab R, Alexandre F. Pattern separation in the hippocampus: distinct circuits under different conditions. Brain Struct Funct 2018; 223:2785-2808. [PMID: 29637298 DOI: 10.1007/s00429-018-1659-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 03/26/2018] [Indexed: 10/17/2022]
Abstract
Pattern separation is a fundamental hippocampal process thought to be critical for distinguishing similar episodic memories, and has long been recognized as a natural function of the dentate gyrus (DG), supporting autoassociative learning in CA3. Understanding how neural circuits within the DG-CA3 network mediate this process has received much interest, yet the exact mechanisms behind remain elusive. Here, we argue for the case that sparse coding is necessary but not sufficient to ensure efficient separation and, alternatively, propose a possible interaction of distinct circuits which, nevertheless, act in synergy to produce a unitary function of pattern separation. The proposed circuits involve different functional granule-cell populations, a primary population mediates sparsification and provides recurrent excitation to the other populations which are related to additional pattern separation mechanisms with higher degrees of robustness against interference in CA3. A variety of top-down and bottom-up factors, such as motivation, emotion, and pattern similarity, control the selection of circuitry depending on circumstances. According to this framework, a computational model is implemented and tested against model variants in a series of numerical simulations and biological experiments. The results demonstrate that the model combines fast learning, robust pattern separation and high storage capacity. It also accounts for the controversy around the involvement of the DG during memory recall, explains other puzzling findings, and makes predictions that can inform future investigations.
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Affiliation(s)
- Randa Kassab
- INRIA, Bordeaux Sud-Ouest, Talence, France. .,Institut des Maladies Neurodégénératives, University of Bordeaux, CNRS UMR 5293-Case 28, Centre Broca Nouvelle-Aquitaine, 146 rue Léo Saignat, 33076, Bordeaux, France. .,LaBRI, UMR 5800, CNRS, Bordeaux INP, University of Bordeaux, Talence, France.
| | - Frédéric Alexandre
- INRIA, Bordeaux Sud-Ouest, Talence, France.,Institut des Maladies Neurodégénératives, University of Bordeaux, CNRS UMR 5293-Case 28, Centre Broca Nouvelle-Aquitaine, 146 rue Léo Saignat, 33076, Bordeaux, France.,LaBRI, UMR 5800, CNRS, Bordeaux INP, University of Bordeaux, Talence, France
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26
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Moretto JN, Duffy ÁM, Scharfman HE. Acute restraint stress decreases c-fos immunoreactivity in hilar mossy cells of the adult dentate gyrus. Brain Struct Funct 2017; 222:2405-2419. [PMID: 28190104 DOI: 10.1007/s00429-016-1349-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 12/14/2016] [Indexed: 11/29/2022]
Abstract
Although a great deal of information is available about the circuitry of the mossy cells (MCs) of the dentate gyrus (DG) hilus, their activity in vivo is not clear. The immediate early gene c-fos can be used to gain insight into the activity of MCs in vivo, because c-fos protein expression reflects increased neuronal activity. In prior work, it was identified that control rats that were perfusion-fixed after removal from their home cage exhibited c-fos immunoreactivity (ir) in the DG in a spatially stereotyped pattern: ventral MCs and dorsal granule cells (GCs) expressed c-fos protein (Duffy et al., Hippocampus 23:649-655, 2013). In this study, we hypothesized that restraint stress would alter c-fos-ir, because MCs express glucocorticoid type 2 receptors and the DG is considered to be involved in behaviors related to stress or anxiety. We show that acute restraint using a transparent nose cone for just 10 min led to reduced c-fos-ir in ventral MCs compared to control rats. In these comparisons, c-fos-ir was evaluated 30 min after the 10 min-long period of restraint, and if evaluation was later than 30 min c-fos-ir was no longer suppressed. Granule cells (GCs) also showed suppressed c-fos-ir after acute restraint, but it was different than MCs, because the suppression persisted for over 30 min after the restraint. We conclude that c-fos protein expression is rapidly and transiently reduced in ventral hilar MCs after a brief period of restraint, and suppressed longer in dorsal GCs.
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Affiliation(s)
- Jillian N Moretto
- The Nathan Kline Institute of Psychiatric Research, Orangeburg, NY, 10962, USA
| | - Áine M Duffy
- The Nathan Kline Institute of Psychiatric Research, Orangeburg, NY, 10962, USA
| | - Helen E Scharfman
- The Nathan Kline Institute of Psychiatric Research, Orangeburg, NY, 10962, USA. .,Departments of Child and Adolescent Psychiatry, Physiology and Neuroscience, and Psychiatry, New York University Langone Medical Center, New York, NY, 10016, USA.
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27
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Abstract
Mossy cells comprise a large fraction of the cells in the hippocampal dentate gyrus, suggesting that their function in this region is important. They are vulnerable to ischaemia, traumatic brain injury and seizures, and their loss could contribute to dentate gyrus dysfunction in such conditions. Mossy cell function has been unclear because these cells innervate both glutamatergic and GABAergic neurons within the dentate gyrus, contributing to a complex circuitry. It has also been difficult to directly and selectively manipulate mossy cells to study their function. In light of the new data generated using methods to preferentially eliminate or activate mossy cells in mice, it is timely to ask whether mossy cells have become any less enigmatic than they were in the past.
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Affiliation(s)
- Helen E Scharfman
- Departments of Child and Adolescent Psychiatry, Physiology and Neuroscience, and Psychiatry, New York University Langone Medical Center, New York 10016, USA.,Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 10962, USA
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28
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Kam K, Duffy ÁM, Moretto J, LaFrancois JJ, Scharfman HE. Interictal spikes during sleep are an early defect in the Tg2576 mouse model of β-amyloid neuropathology. Sci Rep 2016; 6:20119. [PMID: 26818394 PMCID: PMC4730189 DOI: 10.1038/srep20119] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 12/21/2015] [Indexed: 01/25/2023] Open
Abstract
It has been suggested that neuronal hyperexcitability contributes to Alzheimer's disease (AD), so we asked how hyperexcitability develops in a common mouse model of β-amyloid neuropathology - Tg2576 mice. Using video-EEG recordings, we found synchronized, large amplitude potentials resembling interictal spikes (IIS) in epilepsy at just 5 weeks of age, long before memory impairments or β-amyloid deposition. Seizures were not detected, but they did occur later in life, suggesting that IIS are possibly the earliest stage of hyperexcitability. Interestingly, IIS primarily occurred during rapid-eye movement (REM) sleep, which is notable because REM is associated with increased cholinergic tone and cholinergic impairments are implicated in AD. Although previous studies suggest that cholinergic antagonists would worsen pathophysiology, the muscarinic antagonist atropine reduced IIS frequency. In addition, we found IIS occurred in APP51 mice which overexpress wild type (WT)-APP, although not as uniformly or as early in life as Tg2576 mice. Taken together with results from prior studies, the data suggest that surprising and multiple mechanisms contribute to hyperexcitability. The data also suggest that IIS may be a biomarker for early detection of AD.
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Affiliation(s)
- Korey Kam
- The Nathan Kline Institute for Psychiatric Research Center for Dementia Research Orangeburg, NY 10962, USA.,Graduate Program in Physiology and Neuroscience New York University Langone Medical Center New York, NY 10016, USA
| | - Áine M Duffy
- The Nathan Kline Institute for Psychiatric Research Center for Dementia Research Orangeburg, NY 10962, USA.,Department of Physiology and Neuroscience New York University Langone Medical Center New York, NY 10016, USA
| | - Jillian Moretto
- The Nathan Kline Institute for Psychiatric Research Center for Dementia Research Orangeburg, NY 10962, USA
| | - John J LaFrancois
- The Nathan Kline Institute for Psychiatric Research Center for Dementia Research Orangeburg, NY 10962, USA
| | - Helen E Scharfman
- The Nathan Kline Institute for Psychiatric Research Center for Dementia Research Orangeburg, NY 10962, USA.,Department of Physiology and Neuroscience New York University Langone Medical Center New York, NY 10016, USA.,Department of Child and Adolescent Psychiatry and Psychiatry New York University Langone Medical Center New York, NY 10016, USA
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29
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Ameliorative Effects of Antioxidants on the Hippocampal Accumulation of Pathologic Tau in a Rat Model of Blast-Induced Traumatic Brain Injury. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:4159357. [PMID: 27034735 PMCID: PMC4806690 DOI: 10.1155/2016/4159357] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/15/2015] [Indexed: 01/22/2023]
Abstract
Traumatic brain injury (TBI) can lead to early onset dementia and other related neurodegenerative diseases. We previously demonstrated that damage to the central auditory pathway resulting from blast-induced TBI (bTBI) could be significantly attenuated by a combinatorial antioxidant treatment regimen. In the current study, we examined the localization patterns of normal Tau and the potential blast-induced accumulation of neurotoxic variants of this microtubule-associated protein that are believed to potentiate the neurodegenerative effects associated with synaptic dysfunction in the hippocampus following three successive blast overpressure exposures in nontransgenic rats. We observed a marked increase in the number of both hyperphosphorylated and oligomeric Tau-positive hilar mossy cells and somatic accumulation of endogenous Tau in oligodendrocytes in the hippocampus. Remarkably, a combinatorial regimen of 2,4-disulfonyl α-phenyl tertiary butyl nitrone (HPN-07) and N-acetylcysteine (NAC) resulted in striking reductions in the numbers of both mossy cells and oligodendrocytes positively labeled for these pathological Tau immunoreactivity patterns in response to bTBI. This treatment strategy represents a promising therapeutic approach for simultaneously reducing or eliminating both primary auditory injury and nonauditory changes associated with bTBI-induced hippocampal neurodegeneration.
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Narváez M, Borroto-Escuela DO, Millón C, Gago B, Flores-Burgess A, Santín L, Fuxe K, Narváez JA, Díaz-Cabiale Z. Galanin receptor 2-neuropeptide Y Y1 receptor interactions in the dentate gyrus are related with antidepressant-like effects. Brain Struct Funct 2015; 221:4129-4139. [DOI: 10.1007/s00429-015-1153-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 11/19/2015] [Indexed: 11/30/2022]
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31
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Scharfman HE, Bernstein HL. Potential implications of a monosynaptic pathway from mossy cells to adult-born granule cells of the dentate gyrus. Front Syst Neurosci 2015; 9:112. [PMID: 26347618 PMCID: PMC4541026 DOI: 10.3389/fnsys.2015.00112] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Accepted: 07/20/2015] [Indexed: 11/13/2022] Open
Abstract
The dentate gyrus (DG) is important to many aspects of hippocampal function, but there are many aspects of the DG that are incompletely understood. One example is the role of mossy cells (MCs), a major DG cell type that is glutamatergic and innervates the primary output cells of the DG, the granule cells (GCs). MCs innervate the GCs as well as local circuit neurons that make GABAergic synapses on GCs, so the net effect of MCs on GCs – and therefore the output of the DG – is unclear. Here we first review fundamental information about MCs and the current hypotheses for their role in the normal DG and in diseases that involve the DG. Then we review previously published data which suggest that MCs are a source of input to a subset of GCs that are born in adulthood (adult-born GCs). In addition, we discuss the evidence that adult-born GCs may support the normal inhibitory ‘gate’ functions of the DG, where the GCs are a filter or gate for information from the entorhinal cortical input to area CA3. The implications are then discussed in the context of seizures and temporal lobe epilepsy (TLE). In TLE, it has been suggested that the DG inhibitory gate is weak or broken and MC loss leads to insufficient activation of inhibitory neurons, causing hyperexcitability. That idea was called the “dormant basket cell hypothesis.” Recent data suggest that loss of normal adult-born GCs may also cause disinhibition, and seizure susceptibility. Therefore, we propose a reconsideration of the dormant basket cell hypothesis with an intervening adult-born GC between the MC and basket cell and call this hypothesis the “dormant immature granule cell hypothesis.”
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Affiliation(s)
- Helen E Scharfman
- The Nathan Kline Institute for Psychiatric Research, Orangeburg NY, USA ; New York University Langone Medical Center, New York NY, USA
| | - Hannah L Bernstein
- The Nathan Kline Institute for Psychiatric Research, Orangeburg NY, USA ; New York University Langone Medical Center, New York NY, USA
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Duffy AM, Morales-Corraliza J, Bermudez-Hernandez KM, Schaner MJ, Magagna-Poveda A, Mathews PM, Scharfman HE. Entorhinal cortical defects in Tg2576 mice are present as early as 2-4 months of age. Neurobiol Aging 2014; 36:134-48. [PMID: 25109765 DOI: 10.1016/j.neurobiolaging.2014.07.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 06/30/2014] [Accepted: 07/08/2014] [Indexed: 11/15/2022]
Abstract
The entorhinal cortex (EC) is one of the first brain areas to display neuropathology in Alzheimer's disease. A mouse model which simulates amyloid-β (Aβ) neuropathology, the Tg2576 mouse, was used to address these early changes. Here, we show EC abnormalities occur in 2- to 4-month-old Tg2576 mice, an age before Aβ deposition and where previous studies suggest that there are few behavioral impairments. First we show, using a sandwich enzyme-linked immunosorbent assay, that soluble human Aβ40 and Aβ42 are detectable in the EC of 2-month-old Tg2576 mice before Aβ deposition. We then demonstrate that 2- to 4-month-old Tg2576 mice are impaired at object placement, an EC-dependent cognitive task. Next, we show that defects in neuronal nuclear antigen expression and myelin uptake occur in the superficial layers of the EC in 2- to 4-month-old Tg2576 mice. In slices from Tg2576 mice that contained the EC, there were repetitive field potentials evoked by a single stimulus to the underlying white matter, and a greater response to reduced extracellular magnesium ([Mg(2+)]o), suggesting increased excitability. However, deep layer neurons in Tg2576 mice had longer latencies to antidromic activation than wild type mice. The results show changes in the EC at early ages and suggest that altered excitability occurs before extensive plaque pathology.
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Affiliation(s)
- Aine M Duffy
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA; Department of Child & Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, USA.
| | - Jose Morales-Corraliza
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Keria M Bermudez-Hernandez
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA; Department of Physiology & Neuroscience, Sackler Institute of Graduate Biomedical Sciences, New York University Langone Medical Center, New York, NY, USA
| | - Michael J Schaner
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA
| | - Alejandra Magagna-Poveda
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA
| | - Paul M Mathews
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Helen E Scharfman
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, New York, NY, USA; Department of Child & Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA; Department of Physiology & Neuroscience, New York University Langone Medical Center, New York, NY, USA
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