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Jain S, LaFrancois JJ, Gerencer K, Botterill JJ, Kennedy M, Criscuolo C, Scharfman HE. Increasing adult-born neurons protects mice from epilepsy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.07.08.548217. [PMID: 37502909 PMCID: PMC10369878 DOI: 10.1101/2023.07.08.548217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Neurogenesis occurs in the adult brain in the hippocampal dentate gyrus, an area that contains neurons which are vulnerable to insults and injury, such as severe seizures. Previous studies showed that increasing adult neurogenesis reduced neuronal damage after these seizures. Because the damage typically is followed by chronic life-long seizures (epilepsy), we asked if increasing adult-born neurons would prevent epilepsy. Adult-born neurons were selectively increased by deleting the pro-apoptotic gene Bax from Nestin-expressing progenitors. Tamoxifen was administered at 6 weeks of age to conditionally delete Bax in Nestin-CreERT2 Bax fl/fl mice. Six weeks after tamoxifen administration, severe seizures (status epilepticus; SE) were induced by injection of the convulsant pilocarpine. After mice developed epilepsy, seizure frequency was quantified for 3 weeks. Mice with increased adult-born neurons exhibited fewer chronic seizures. Postictal depression was reduced also. These results were primarily in female mice, possibly because they were the more affected by Bax deletion than males, consistent with sex differences in Bax. The female mice with enhanced adult-born neurons also showed less neuronal loss of hilar mossy cells and hilar somatostatin-expressing neurons than wild type females or males, which is notable because these two hilar cell types are implicated in epileptogenesis. The results suggest that selective Bax deletion to increase adult-born neurons can reduce experimental epilepsy, and the effect shows a striking sex difference. The results are surprising in light of past studies showing that suppressing adult-born neurons can also reduce chronic seizures.
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Affiliation(s)
- Swati Jain
- Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962
| | - John J. LaFrancois
- Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962
| | - Kasey Gerencer
- Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Current address: Department of Psychology, The University of Maine, Orono, ME 04469
| | - Justin J. Botterill
- Department of Anatomy, Physiology, & Pharmacology, College of Medicine, Saskatoon, SK S7N 5E5
| | - Meghan Kennedy
- Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962
| | - Chiara Criscuolo
- Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Departments of Child and Adolescent Psychiatry, New York University Grossman School of Medicine, New York, NY 10016
| | - Helen E. Scharfman
- Center for Dementia Research, The Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962
- Departments of Child and Adolescent Psychiatry, New York University Grossman School of Medicine, New York, NY 10016
- Departments of Neuroscience & Physiology, Psychiatry, and the New York University, Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016
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2
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Moreira JF, Solá S. Dynamics of Neurogenic Signals as Biological Switchers of Brain Plasticity. Stem Cell Rev Rep 2024:10.1007/s12015-024-10788-2. [PMID: 39259446 DOI: 10.1007/s12015-024-10788-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2024] [Indexed: 09/13/2024]
Abstract
The discovery of adult neurogenesis in the middle of the past century is considered one of the most important breakthroughs in neuroscience. Despite its controversial nature, this discovery shaped our concept of neural plasticity, revolutionizing the way we look at our brains. In fact, after the discovery of adult neurogenesis, we started to consider the brain as something even more dynamic and highly adaptable. In neurogenic niches, adult neurogenesis is supported by neural stem cells (NSCs). These cells possess a unique set of characteristics such as being quiescent for long periods while actively sensing and reacting to their surroundings to influence a multitude of processes, including the generation of new neurons and glial cells. Therefore, NSCs can be viewed as sentinels to our brain's homeostasis, being able to replace damaged cells and simultaneously secrete numerous factors that restore regular brain function. In addition, it is becoming increasingly evident that NSCs play a central role in memory formation and consolidation. In this review, we will dissect how NSCs influence their surroundings through paracrine and autocrine types of action. We will also depict the mechanism of action of each factor. Finally, we will describe how NSCs integrate different and often opposing signals to guide their fate.
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Affiliation(s)
- João F Moreira
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisbon, Portugal
| | - Susana Solá
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003, Lisbon, Portugal.
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3
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Frechou MA, Martin SS, McDermott KD, Huaman EA, Gökhan Ş, Tomé WA, Coen-Cagli R, Gonçalves JT. Adult neurogenesis improves spatial information encoding in the mouse hippocampus. Nat Commun 2024; 15:6410. [PMID: 39080283 PMCID: PMC11289285 DOI: 10.1038/s41467-024-50699-x] [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: 12/15/2022] [Accepted: 06/24/2024] [Indexed: 08/02/2024] Open
Abstract
Adult neurogenesis is a unique form of neuronal plasticity in which newly generated neurons are integrated into the adult dentate gyrus in a process that is modulated by environmental stimuli. Adult-born neurons can contribute to spatial memory, but it is unknown whether they alter neural representations of space in the hippocampus. Using in vivo two-photon calcium imaging, we find that male and female mice previously housed in an enriched environment, which triggers an increase in neurogenesis, have increased spatial information encoding in the dentate gyrus. Ablating adult neurogenesis blocks the effect of enrichment and lowers spatial information, as does the chemogenetic silencing of adult-born neurons. Both ablating neurogenesis and silencing adult-born neurons decreases the calcium activity of dentate gyrus neurons, resulting in a decreased amplitude of place-specific responses. These findings are in contrast with previous studies that suggested a predominantly inhibitory action for adult-born neurons. We propose that adult neurogenesis improves representations of space by increasing the gain of dentate gyrus neurons and thereby improving their ability to tune to spatial features. This mechanism may mediate the beneficial effects of environmental enrichment on spatial learning and memory.
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Affiliation(s)
- M Agustina Frechou
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
- Gottesmann Institute for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
- Laboratory of Neurotechnology and Biophysics, The Rockefeller University, New York, NY, USA
| | - Sunaina S Martin
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
- Gottesmann Institute for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Psychology, University of California San Diego, La Jolla, CA, USA
| | - Kelsey D McDermott
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
- Gottesmann Institute for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Evan A Huaman
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
- Gottesmann Institute for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Şölen Gökhan
- Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Wolfgang A Tomé
- Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Ruben Coen-Cagli
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, USA
| | - J Tiago Gonçalves
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA.
- Gottesmann Institute for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of Medicine, Bronx, NY, USA.
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4
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Brenowitz EA, Lent KL, Miller KE, Perkel DJ. Adult neurogenesis is necessary for functional regeneration of a forebrain neural circuit. Proc Natl Acad Sci U S A 2024; 121:e2400596121. [PMID: 38968119 PMCID: PMC11252730 DOI: 10.1073/pnas.2400596121] [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: 01/10/2024] [Accepted: 05/21/2024] [Indexed: 07/07/2024] Open
Abstract
In adult songbirds, new neurons are born in large numbers in the proliferative ventricular zone in the telencephalon and migrate to the adjacent song control region HVC (acronym used as proper name) [A. Reiner et al., J. Comp. Neurol. 473, 377-414 (2004)]. Many of these new neurons send long axonal projections to the robust nucleus of the arcopallium (RA). The HVC-RA circuit is essential for producing stereotyped learned song. The function of adult neurogenesis in this circuit has not been clear. A previous study suggested that it is important for the production of well-structured songs [R. E. Cohen, M. Macedo-Lima, K. E. Miller, E. A. Brenowitz, J. Neurosci. 36, 8947-8956 (2016)]. We tested this hypothesis by infusing the neuroblast migration inhibitor cyclopamine into HVC of male Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii) to block seasonal regeneration of the HVC-RA circuit. Decreasing the number of new neurons in HVC prevented both the increase in spontaneous electrical activity of RA neurons and the improved structure of songs that would normally occur as sparrows enter breeding condition. These results show that the incorporation of new neurons into the adult HVC is necessary for the recovery of both electrical activity and song behavior in breeding birds and demonstrate the value of the bird song system as a model for investigating adult neurogenesis at the level of long projection neural circuits.
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Affiliation(s)
- Eliot A. Brenowitz
- Department of Psychology, University of Washington, Seattle, WA98195
- Department of Biology, University of Washington, Seattle, WA98195
| | - Karin L. Lent
- Department of Psychology, University of Washington, Seattle, WA98195
- Department of Biology, University of Washington, Seattle, WA98195
| | - Kimberly E. Miller
- Department of Psychology, University of Washington, Seattle, WA98195
- Department of Biology, University of Washington, Seattle, WA98195
| | - David J. Perkel
- Department of Biology, University of Washington, Seattle, WA98195
- Department of Otolaryngology, University of Washington, Seattle, WA98195
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5
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Stephens GS, Park J, Eagle A, You J, Silva-Pérez M, Fu CH, Choi S, Romain CPS, Sugimoto C, Buffington SA, Zheng Y, Costa-Mattioli M, Liu Y, Robison AJ, Chin J. Persistent ∆FosB expression limits recurrent seizure activity and provides neuroprotection in the dentate gyrus of APP mice. Prog Neurobiol 2024; 237:102612. [PMID: 38642602 PMCID: PMC11406539 DOI: 10.1016/j.pneurobio.2024.102612] [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: 04/03/2023] [Revised: 03/14/2024] [Accepted: 04/12/2024] [Indexed: 04/22/2024]
Abstract
Recurrent seizures lead to accumulation of the activity-dependent transcription factor ∆FosB in hippocampal dentate granule cells in both mouse models of epilepsy and mouse models of Alzheimer's disease (AD), which is also associated with increased incidence of seizures. In patients with AD and related mouse models, the degree of ∆FosB accumulation corresponds with increasing severity of cognitive deficits. We previously found that ∆FosB impairs spatial memory in mice by epigenetically regulating expression of target genes such as calbindin that are involved in synaptic plasticity. However, the suppression of calbindin in conditions of neuronal hyperexcitability has been demonstrated to provide neuroprotection to dentate granule cells, indicating that ∆FosB may act over long timescales to coordinate neuroprotective pathways. To test this hypothesis, we used viral-mediated expression of ∆JunD to interfere with ∆FosB signaling over the course of several months in transgenic mice expressing mutant human amyloid precursor protein (APP), which exhibit spontaneous seizures and develop AD-related neuropathology and cognitive deficits. Our results demonstrate that persistent ∆FosB activity acts through discrete modes of hippocampal target gene regulation to modulate neuronal excitability, limit recurrent seizure activity, and provide neuroprotection to hippocampal dentate granule cells in APP mice.
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Affiliation(s)
| | - Jin Park
- Department of Neuroscience, Baylor College of Medicine, USA
| | - Andrew Eagle
- Department of Physiology, Michigan State University, USA
| | - Jason You
- Department of Neuroscience, Baylor College of Medicine, USA
| | | | - Chia-Hsuan Fu
- Department of Neuroscience, Baylor College of Medicine, USA
| | - Sumin Choi
- Department of Neuroscience, Baylor College of Medicine, USA
| | | | - Chiho Sugimoto
- Department of Physiology, Michigan State University, USA
| | - Shelly A Buffington
- Center for Precision Environmental Health, Department of Neuroscience, Baylor College of Medicine, USA
| | - Yi Zheng
- Department of Neuroscience, Baylor College of Medicine, USA
| | | | - Yin Liu
- Department of Neurobiology and Anatomy, McGovern Medical School at UT Health, USA
| | - A J Robison
- Department of Physiology, Michigan State University, USA
| | - Jeannie Chin
- Department of Neuroscience, Baylor College of Medicine, USA.
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6
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Lazarov O, Gupta M, Kumar P, Morrissey Z, Phan T. Memory circuits in dementia: The engram, hippocampal neurogenesis and Alzheimer's disease. Prog Neurobiol 2024; 236:102601. [PMID: 38570083 PMCID: PMC11221328 DOI: 10.1016/j.pneurobio.2024.102601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 03/20/2024] [Accepted: 03/22/2024] [Indexed: 04/05/2024]
Abstract
Here, we provide an in-depth consideration of our current understanding of engrams, spanning from molecular to network levels, and hippocampal neurogenesis, in health and Alzheimer's disease (AD). This review highlights novel findings in these emerging research fields and future research directions for novel therapeutic avenues for memory failure in dementia. Engrams, memory in AD, and hippocampal neurogenesis have each been extensively studied. The integration of these topics, however, has been relatively less deliberated, and is the focus of this review. We primarily focus on the dentate gyrus (DG) of the hippocampus, which is a key area of episodic memory formation. Episodic memory is significantly impaired in AD, and is also the site of adult hippocampal neurogenesis. Advancements in technology, especially opto- and chemogenetics, have made sophisticated manipulations of engram cells possible. Furthermore, innovative methods have emerged for monitoring neurons, even specific neuronal populations, in vivo while animals engage in tasks, such as calcium imaging. In vivo calcium imaging contributes to a more comprehensive understanding of engram cells. Critically, studies of the engram in the DG using these technologies have shown the important contribution of hippocampal neurogenesis for memory in both health and AD. Together, the discussion of these topics provides a holistic perspective that motivates questions for future research.
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Affiliation(s)
- Orly Lazarov
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA.
| | - Muskan Gupta
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Pavan Kumar
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Zachery Morrissey
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Trongha Phan
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
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7
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Li H, Tamura R, Hayashi D, Asai H, Koga J, Ando S, Yokota S, Kaneko J, Sakurai K, Sumiyoshi A, Yamamoto T, Hikishima K, Tanaka KZ, McHugh TJ, Hisatsune T. Silencing dentate newborn neurons alters excitatory/inhibitory balance and impairs behavioral inhibition and flexibility. SCIENCE ADVANCES 2024; 10:eadk4741. [PMID: 38198539 PMCID: PMC10780870 DOI: 10.1126/sciadv.adk4741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 12/13/2023] [Indexed: 01/12/2024]
Abstract
Adult neurogenesis confers the hippocampus with unparalleled neural plasticity, essential for intricate cognitive functions. The specific influence of sparse newborn neurons (NBNs) in modulating neural activities and subsequently steering behavior, however, remains obscure. Using an engineered NBN-tetanus toxin mouse model (NBN-TeTX), we noninvasively silenced NBNs, elucidating their crucial role in impulse inhibition and cognitive flexibility as evidenced through Morris water maze reversal learning and Go/Nogo task in operant learning. Task-based functional MRI (tb-fMRI) paired with operant learning revealed dorsal hippocampal hyperactivation during the Nogo task in male NBN-TeTX mice, suggesting that hippocampal hyperexcitability might underlie the observed behavioral deficits. Additionally, resting-state fMRI (rs-fMRI) exhibited enhanced functional connectivity between the dorsal and ventral dentate gyrus following NBN silencing. Further investigations into the activities of PV+ interneurons and mossy cells highlighted the indispensability of NBNs in maintaining the hippocampal excitation/inhibition balance. Our findings emphasize that the neural plasticity driven by NBNs extensively modulates the hippocampus, sculpting inhibitory control and cognitive flexibility.
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Affiliation(s)
- Haowei Li
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Risako Tamura
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Daiki Hayashi
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Hirotaka Asai
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Junya Koga
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Shota Ando
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Sayumi Yokota
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Jun Kaneko
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Keisuke Sakurai
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Akira Sumiyoshi
- Department of Molecular Imaging and Theranostics, National Institutes for Quantum and Radiological Science and Technology, Chiba, Japan
| | - Tadashi Yamamoto
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Keigo Hikishima
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Kazumasa Z. Tanaka
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, Saitama, Japan
| | - Thomas J. McHugh
- Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, Saitama, Japan
| | - Tatsuhiro Hisatsune
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
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8
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Chang WL, Hen R. Adult Neurogenesis, Context Encoding, and Pattern Separation: A Pathway for Treating Overgeneralization. ADVANCES IN NEUROBIOLOGY 2024; 38:163-193. [PMID: 39008016 DOI: 10.1007/978-3-031-62983-9_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
In mammals, the subgranular zone of the dentate gyrus is one of two brain regions (with the subventricular zone of the olfactory bulb) that continues to generate new neurons throughout adulthood, a phenomenon known as adult hippocampal neurogenesis (AHN) (Eriksson et al., Nat Med 4:1313-1317, 1998; García-Verdugo et al., J Neurobiol 36:234-248, 1998). The integration of these new neurons into the dentate gyrus (DG) has implications for memory encoding, with unique firing and wiring properties of immature neurons that affect how the hippocampal network encodes and stores attributes of memory. In this chapter, we will describe the process of AHN and properties of adult-born cells as they integrate into the hippocampal circuit and mature. Then, we will discuss some methodological considerations before we review evidence for the role of AHN in two major processes supporting memory that are performed by the DG. First, we will discuss encoding of contextual information for episodic memories and how this is facilitated by AHN. Second, will discuss pattern separation, a major role of the DG that reduces interference for the formation of new memories. Finally, we will review clinical and translational considerations, suggesting that stimulation of AHN may help decrease overgeneralization-a common endophenotype of mood, anxiety, trauma-related, and age-related disorders.
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Affiliation(s)
- Wei-Li Chang
- Departments of Psychiatry and Neuroscience, Columbia University, New York, NY, USA
- Division of Systems Neuroscience, New York State Psychiatric Institute, New York, NY, USA
| | - Rene Hen
- Departments of Psychiatry and Neuroscience, Columbia University, New York, NY, USA.
- Division of Systems Neuroscience, New York State Psychiatric Institute, New York, NY, USA.
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9
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Tuncdemir SN, Grosmark AD, Chung H, Luna VM, Lacefield CO, Losonczy A, Hen R. Adult-born granule cells facilitate remapping of spatial and non-spatial representations in the dentate gyrus. Neuron 2023; 111:4024-4039.e7. [PMID: 37820723 PMCID: PMC10841867 DOI: 10.1016/j.neuron.2023.09.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 06/10/2023] [Accepted: 09/13/2023] [Indexed: 10/13/2023]
Abstract
Adult-born granule cells (abGCs) have been implicated in memory discrimination through a neural computation known as pattern separation. Here, using in vivo Ca2+ imaging, we examined how chronic ablation or acute chemogenetic silencing of abGCs affects the activity of mature granule cells (mGCs). In both cases, we observed altered remapping of mGCs. Rather than broadly modulating the activity of all mGCs, abGCs promote the remapping of place cells' firing fields while increasing rate remapping of mGCs that represent sensory cues. In turn, these remapping deficits are associated with behavioral impairments in animals' ability to correctly identify new goal locations. Thus, abGCs facilitate pattern separation through the formation of non-overlapping representations for identical sensory cues encountered in different locations. In the absence of abGCs, the dentate gyrus shifts to a state that is dominated by cue information, a situation that is consistent with the overgeneralization often observed in anxiety or age-related disorders.
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Affiliation(s)
- Sebnem N Tuncdemir
- Departments of Psychiatry and Neuroscience, Columbia University, New York, NY 10032, USA; Division of Systems Neuroscience, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Andres D Grosmark
- Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Hannah Chung
- Division of Systems Neuroscience, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Victor M Luna
- Departments of Psychiatry and Neuroscience, Columbia University, New York, NY 10032, USA; Division of Systems Neuroscience, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Clay O Lacefield
- Departments of Psychiatry and Neuroscience, Columbia University, New York, NY 10032, USA; Division of Systems Neuroscience, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Attila Losonczy
- Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Rene Hen
- Departments of Psychiatry and Neuroscience, Columbia University, New York, NY 10032, USA; Division of Systems Neuroscience, New York State Psychiatric Institute, New York, NY 10032, USA.
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10
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Zanirati G, Shetty PA, Shetty AK. Neural stem cells persist to generate new neurons in the hippocampus of adult and aged human brain - Fiction or accurate? Ageing Res Rev 2023; 92:102133. [PMID: 38000512 PMCID: PMC10843673 DOI: 10.1016/j.arr.2023.102133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 11/18/2023] [Indexed: 11/26/2023]
Abstract
Adult neurogenesis, comprising the generation, differentiation and integration of new neurons in the mature brain, has emerged as a dynamic area of research over decades. The discovery of adult neurogenesis was a paradigm shift to comprehend mechanisms underlying brain plasticity, cognitive function, and neurological disorders. This review deliberates significant findings from articles published over four decades on adult neurogenesis, highlighting key milestones, methodological advances, and controversies that have shaped our comprehension of the phenomenon of adult neurogenesis. Early skepticism gave way to a rich body of evidence via various reliable approaches. Studies on neurogenic niches, microenvironmental factors, molecular regulators, and functional implications have uncovered the involvement of adult neurogenesis in learning, memory, mood, and even neurological and neurodegenerative conditions. Despite significant progress, several questions still need to be answered, including the exact contributions of new neurons to brain function, their integration into existing circuits, and the impact of enhancing adult neurogenesis in the human hippocampus. While the existence of robust neurogenesis in the adult and aged human hippocampus is yet to be confirmed, this review highlights evidence from a significant number of studies supporting the persistence of hippocampal neurogenesis during adulthood and aging in humans, including in some neurological conditions, such as epilepsy and Alzheimer's disease. Nonetheless, additional large-scale studies using single cell-RNA-seq, single nucleus-RNA-seq, and spatial transcriptomics are critical to validate the presence and contribution of hippocampal neurogenesis in the pathophysiology of various neurological and neurodegenerative conditions at different stages of the disease. There is also a need to develop standardized protocols for analyzing postmortem hippocampal tissues for cellular and molecular analyses.
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Affiliation(s)
- Gabriele Zanirati
- Brain Institute of Rio Grande do Sul (BraIns), Pontifical Catholic University of Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil
| | - Padmashri A Shetty
- Institute for Regenerative Medicine, Department of Cell Biology and Genetics, Texas A&M University School of Medicine, College Station, TX, USA; Department of Psychiatry, Foster School of Medicine, Texas Tech Health Science Center, El Paso, TX, USA
| | - Ashok K Shetty
- Institute for Regenerative Medicine, Department of Cell Biology and Genetics, Texas A&M University School of Medicine, College Station, TX, USA.
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11
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Berdugo‐Vega G, Dhingra S, Calegari F. Sharpening the blades of the dentate gyrus: how adult-born neurons differentially modulate diverse aspects of hippocampal learning and memory. EMBO J 2023; 42:e113524. [PMID: 37743770 PMCID: PMC11059975 DOI: 10.15252/embj.2023113524] [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: 01/16/2023] [Revised: 06/19/2023] [Accepted: 08/18/2023] [Indexed: 09/26/2023] Open
Abstract
For decades, the mammalian hippocampus has been the focus of cellular, anatomical, behavioral, and computational studies aimed at understanding the fundamental mechanisms underlying cognition. Long recognized as the brain's seat for learning and memory, a wealth of knowledge has been accumulated on how the hippocampus processes sensory input, builds complex associations between objects, events, and space, and stores this information in the form of memories to be retrieved later in life. However, despite major efforts, our understanding of hippocampal cognitive function remains fragmentary, and models trying to explain it are continually revisited. Here, we review the literature across all above-mentioned domains and offer a new perspective by bringing attention to the most distinctive, and generally neglected, feature of the mammalian hippocampal formation, namely, the structural separability of the two blades of the dentate gyrus into "supra-pyramidal" and "infra-pyramidal". Next, we discuss recent reports supporting differential effects of adult neurogenesis in the regulation of mature granule cell activity in these two blades. We propose a model for how differences in connectivity and adult neurogenesis in the two blades can potentially provide a substrate for subtly different cognitive functions.
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Affiliation(s)
- Gabriel Berdugo‐Vega
- CRTD‐Center for Regenerative Therapies DresdenTechnische Universität DresdenDresdenGermany
- Present address:
Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale Lausanne (EPFL)LausanneSwitzerland
| | - Shonali Dhingra
- CRTD‐Center for Regenerative Therapies DresdenTechnische Universität DresdenDresdenGermany
| | - Federico Calegari
- CRTD‐Center for Regenerative Therapies DresdenTechnische Universität DresdenDresdenGermany
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12
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Zhang L, Xu X, Ma L, Wang X, Jin M, Li L, Ni H. Zinc Water Prevents Autism-Like Behaviors in the BTBR Mice. Biol Trace Elem Res 2023; 201:4779-4792. [PMID: 36602746 PMCID: PMC10415509 DOI: 10.1007/s12011-022-03548-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 12/24/2022] [Indexed: 01/06/2023]
Abstract
This study aims to explore the effects of zinc water on autism-like behavior, convulsion threshold, and neurogenesis in ASD model animals. This study used the young BTBR ASD mouse model to explore the effect of a 6-week zinc water supplementation on ASD-like behaviors such as repetitive behavior and social communication disorder, seizure threshold, and the correlation with excitability regulation. The mice were divided into four groups of normal controls (B6) and models (BTBR) who did and did not receive zinc supplementation in water (B6, B6 + zinc, BTBR, and BTBR + zinc). For morphological changes in the hippocampus, we selected two indicators: hippocampal mossy fiber sprouting and neurogenesis. ASD-like behavior testing, seizure threshold determination, Timm staining, and neurogenesis-related assays-represented by Ki67 and DCX-were performed after 6 weeks of zinc supplementation. Our results show that zinc water can prevent autism-like behavior, reduce susceptibility to convulsions, and increase the proliferation of hippocampal progenitor cells in BTBR mice but has less effect on mossy fiber sprouting and neural progenitor cell differentiation. Zinc water reduces autism-like behavior in a partially inherited autism model mice-BTBR-which may be associated with hippocampal neural precursor cell proliferation and reversed hyperexcitability.
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Affiliation(s)
- Li Zhang
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Xiaowen Xu
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Liya Ma
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Xinxin Wang
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Meifang Jin
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Lili Li
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Hong Ni
- Division of Brain Science, Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China.
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13
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Chen L, Xu Y, Cheng H, Li Z, Lai N, Li M, Ruan Y, Zheng Y, Fei F, Xu C, Ma J, Wang S, Gu Y, Han F, Chen Z, Wang Y. Adult-born neurons in critical period maintain hippocampal seizures via local aberrant excitatory circuits. Signal Transduct Target Ther 2023; 8:225. [PMID: 37280192 DOI: 10.1038/s41392-023-01433-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 03/15/2023] [Accepted: 04/06/2023] [Indexed: 06/08/2023] Open
Abstract
Temporal lobe epilepsy (TLE), one common type of medically refractory epilepsy, is accompanied with altered adult-born dentate granule cells (abDGCs). However, the causal role of abDGCs in recurrent seizures of TLE is not fully understood. Here, taking advantage of optogenetic and chemogenetic tools to selectively manipulate abDGCs in a reversible manner, combined with Ca2+ fiber photometry, trans-synaptic viral tracing, in vivo/vitro electrophysiology approaches, we aimed to test the role of abDGCs born at different period of epileptogenic insult in later recurrent seizures in mouse TLE models. We found that abDGCs were functionally inhibited during recurrent seizures. Optogenetic activation of abDGCs significantly extended, while inhibition curtailed, the seizure duration. This seizure-modulating effect was attributed to specific abDGCs born at a critical early phase after kindled status, which experienced specific type of circuit re-organization. Further, abDGCs extended seizure duration via local excitatory circuit with early-born granule cells (ebDGCs). Repeated modulation of "abDGC-ebDGC" circuit may easily induce a change of synaptic plasticity, and achieve long-term anti-seizure effects in both kindling and kainic acid-induced TLE models. Together, we demonstrate that abDGCs born at a critical period of epileptogenic insult maintain seizure duration via local aberrant excitatory circuits, and inactivation of these aberrant circuits can long-termly alleviate severity of seizures. This provides a deeper and more comprehensive understanding of the potential pathological changes of abDGCs circuit and may be helpful for the precise treatment in TLE.
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Affiliation(s)
- Liying Chen
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yingwei Xu
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, China
| | - Heming Cheng
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Zhongxia Li
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
- Zhejiang Rehabilitation Medical Center Department, The Third Affiliated Hospital, Zhejiang Chinese Medical University, Hangzhou, China
| | - Nanxi Lai
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, China
| | - Menghan Li
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yeping Ruan
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yang Zheng
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Fan Fei
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Cenglin Xu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jiao Ma
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, China
| | - Shuang Wang
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yan Gu
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, China
| | - Feng Han
- Key Laboratory of Cardiovascular & Cerebrovascular Medicine, Drug Target and Drug Discovery Center, School of Pharmacy, Nanjing Medical University, Nanjing, China
| | - Zhong Chen
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, China.
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China.
| | - Yi Wang
- Institute of Pharmacology & Toxicology, College of Pharmaceutical Sciences, School of Medicine, Zhejiang University, Hangzhou, China.
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China.
- Zhejiang Rehabilitation Medical Center Department, The Third Affiliated Hospital, Zhejiang Chinese Medical University, Hangzhou, China.
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14
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Jiang M, Jang SE, Zeng L. The Effects of Extrinsic and Intrinsic Factors on Neurogenesis. Cells 2023; 12:cells12091285. [PMID: 37174685 PMCID: PMC10177620 DOI: 10.3390/cells12091285] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/18/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
In the mammalian brain, neurogenesis is maintained throughout adulthood primarily in two typical niches, the subgranular zone (SGZ) of the dentate gyrus and the subventricular zone (SVZ) of the lateral ventricles and in other nonclassic neurogenic areas (e.g., the amygdala and striatum). During prenatal and early postnatal development, neural stem cells (NSCs) differentiate into neurons and migrate to appropriate areas such as the olfactory bulb where they integrate into existing neural networks; these phenomena constitute the multistep process of neurogenesis. Alterations in any of these processes impair neurogenesis and may even lead to brain dysfunction, including cognitive impairment and neurodegeneration. Here, we first summarize the main properties of mammalian neurogenic niches to describe the cellular and molecular mechanisms of neurogenesis. Accumulating evidence indicates that neurogenesis plays an integral role in neuronal plasticity in the brain and cognition in the postnatal period. Given that neurogenesis can be highly modulated by a number of extrinsic and intrinsic factors, we discuss the impact of extrinsic (e.g., alcohol) and intrinsic (e.g., hormones) modulators on neurogenesis. Additionally, we provide an overview of the contribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection to persistent neurological sequelae such as neurodegeneration, neurogenic defects and accelerated neuronal cell death. Together, our review provides a link between extrinsic/intrinsic factors and neurogenesis and explains the possible mechanisms of abnormal neurogenesis underlying neurological disorders.
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Affiliation(s)
- Mei Jiang
- Department of Human Anatomy, Dongguan Key Laboratory of Stem Cell and Regenerative Tissue Engineering, Dongguan Campus, Guangdong Medical University, Dongguan 523808, China
| | - Se Eun Jang
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore 308433, Singapore
| | - Li Zeng
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore 308433, Singapore
- Neuroscience and Behavioral Disorders Program, DUKE-NUS Graduate Medical School, Singapore 169857, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technology University, Novena Campus, 11 Mandalay Road, Singapore 308232, Singapore
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15
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Parylak SL, Qiu F, Linker SB, Gallina IS, Lim CK, Preciado D, McDonald AH, Zhou X, Gage FH. Neuronal activity-related transcription is blunted in immature compared to mature dentate granule cells. Hippocampus 2023; 33:412-423. [PMID: 36811254 PMCID: PMC10985790 DOI: 10.1002/hipo.23515] [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: 09/26/2022] [Revised: 02/01/2023] [Accepted: 02/07/2023] [Indexed: 02/24/2023]
Abstract
Immature dentate granule cells (DGCs) generated in the hippocampus during adulthood are believed to play a unique role in dentate gyrus (DG) function. Although immature DGCs have hyperexcitable membrane properties in vitro, the consequences of this hyperexcitability in vivo remain unclear. In particular, the relationship between experiences that activate the DG, such as exploration of a novel environment (NE), and downstream molecular processes that modify DG circuitry in response to cellular activation is unknown in this cell population. We first performed quantification of immediate early gene (IEG) proteins in immature (5-week-old) and mature (13-week-old) DGCs from mice exposed to a NE. Paradoxically, we observed lower IEG protein expression in hyperexcitable immature DGCs. We then isolated nuclei from active and inactive immature DGCs and performed single-nuclei RNA-Sequencing. Compared to mature nuclei collected from the same animal, immature DGC nuclei showed less activity-induced transcriptional change, even though they were classified as active based on expression of ARC protein. These results demonstrate that the coupling of spatial exploration, cellular activation, and transcriptional change differs between immature and mature DGCs, with blunted activity-induced changes in immature cells.
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Affiliation(s)
- Sarah L Parylak
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Fan Qiu
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Sara B Linker
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Iryna S Gallina
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Christina K Lim
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - David Preciado
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Aidan H McDonald
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Xavier Zhou
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
| | - Fred H Gage
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California, USA
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16
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Kitchigina V, Shubina L. Oscillations in the dentate gyrus as a tool for the performance of the hippocampal functions: Healthy and epileptic brain. Prog Neuropsychopharmacol Biol Psychiatry 2023; 125:110759. [PMID: 37003419 DOI: 10.1016/j.pnpbp.2023.110759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 03/17/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
The dentate gyrus (DG) is part of the hippocampal formation and is essential for important cognitive processes such as navigation and memory. The oscillatory activity of the DG network is believed to play a critical role in cognition. DG circuits generate theta, beta, and gamma rhythms, which participate in the specific information processing performed by DG neurons. In the temporal lobe epilepsy (TLE), cognitive abilities are impaired, which may be due to drastic alterations in the DG structure and network activity during epileptogenesis. The theta rhythm and theta coherence are especially vulnerable in dentate circuits; disturbances in DG theta oscillations and their coherence may be responsible for general cognitive impairments observed during epileptogenesis. Some researchers suggested that the vulnerability of DG mossy cells is a key factor in the genesis of TLE, but others did not support this hypothesis. The aim of the review is not only to present the current state of the art in this field of research but to help pave the way for future investigations by highlighting the gaps in our knowledge to completely appreciate the role of DG rhythms in brain functions. Disturbances in oscillatory activity of the DG during TLE development may be a diagnostic marker in the treatment of this disease.
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Affiliation(s)
- Valentina Kitchigina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia.
| | - Liubov Shubina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia
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17
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Ash AM, Regele-Blasco E, Seib DR, Chahley E, Skelton PD, Luikart BW, Snyder JS. Adult-born neurons inhibit developmentally-born neurons during spatial learning. Neurobiol Learn Mem 2023; 198:107710. [PMID: 36572174 DOI: 10.1016/j.nlm.2022.107710] [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: 10/12/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022]
Abstract
Ongoing neurogenesis in the dentate gyrus (DG) subregion of the hippocampus results in a heterogenous population of neurons. Immature adult-born neurons (ABNs) have physiological and anatomical properties that may give them a unique role in learning. For example, compared to older granule neurons, they have greater somatic excitability, which could facilitate their recruitment into memory traces. However, recruitment is also likely to depend on interactions with other DG neurons through processes such as lateral inhibition. Immature ABNs target inhibitory interneurons and, compared to older neurons, they receive less GABAergic inhibition. Thus, they may induce lateral inhibition of mature DG neurons while being less susceptible to inhibition themselves. To test this we used a chemogenetic approach to silence immature ABNs as rats learned a spatial water maze task, and measured activity (Fos expression) in ABNs and developmentally-born neurons (DBNs). A retrovirus expressing the inhibitory DREADD receptor, hM4Di, was injected into the dorsal DG of male rats at 6w to infect neurons born in adulthood. Animals were also injected with BrdU to label DBNs or ABNs. DBNs were significantly more active than immature 4-week-old ABNs. Silencing 4-week-old ABNs did not alter learning but it increased activity in DBNs. However, silencing ABNs did not affect activation in other ABNs within the DG. Silencing ABNs also did not alter Fos expression in parvalbumin- and somatostatin-expressing interneurons. Collectively, these results suggest that ABNs may directly inhibit DBN activity during hippocampal-dependent learning, which may be relevant for maintaining sparse hippocampal representations of experienced events.
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Affiliation(s)
- Alyssa M Ash
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Elena Regele-Blasco
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Désirée R Seib
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Erin Chahley
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Patrick D Skelton
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States
| | - Bryan W Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States
| | - Jason S Snyder
- Department of Psychology, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.
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18
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Tran LM, Santoro A, Liu L, Josselyn SA, Richards BA, Frankland PW. Adult neurogenesis acts as a neural regularizer. Proc Natl Acad Sci U S A 2022; 119:e2206704119. [PMID: 36322739 PMCID: PMC9659416 DOI: 10.1073/pnas.2206704119] [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: 04/17/2022] [Accepted: 09/11/2022] [Indexed: 01/09/2023] Open
Abstract
New neurons are continuously generated in the subgranular zone of the dentate gyrus throughout adulthood. These new neurons gradually integrate into hippocampal circuits, forming new naive synapses. Viewed from this perspective, these new neurons may represent a significant source of "wiring" noise in hippocampal networks. In machine learning, such noise injection is commonly used as a regularization technique. Regularization techniques help prevent overfitting training data and allow models to generalize learning to new, unseen data. Using a computational modeling approach, here we ask whether a neurogenesis-like process similarly acts as a regularizer, facilitating generalization in a category learning task. In a convolutional neural network (CNN) trained on the CIFAR-10 object recognition dataset, we modeled neurogenesis as a replacement/turnover mechanism, where weights for a randomly chosen small subset of hidden layer neurons were reinitialized to new values as the model learned to categorize 10 different classes of objects. We found that neurogenesis enhanced generalization on unseen test data compared to networks with no neurogenesis. Moreover, neurogenic networks either outperformed or performed similarly to networks with conventional noise injection (i.e., dropout, weight decay, and neural noise). These results suggest that neurogenesis can enhance generalization in hippocampal learning through noise injection, expanding on the roles that neurogenesis may have in cognition.
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Affiliation(s)
- Lina M. Tran
- Neuroscience and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Vector Institute, Toronto, ON, Canada
| | | | - Lulu Liu
- Neuroscience and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Sheena A. Josselyn
- Neuroscience and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Department of Psychology, University of Toronto, Toronto, ON, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Blake A. Richards
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- School of Computer Science, McGill University, Montreal, QC, Canada
- Mila, Montreal, QC, Canada
- Learning in Machines and Brains, Canadian Institute for Advanced Research, Toronto, ON, Canada
| | - Paul W. Frankland
- Neuroscience and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Department of Psychology, University of Toronto, Toronto, ON, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Child and Brain Development Program, Canadian Institute for Advanced Research, Toronto, ON, Canada
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19
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Adult-born dentate granule cells promote hippocampal population sparsity. Nat Neurosci 2022; 25:1481-1491. [PMID: 36216999 PMCID: PMC9630129 DOI: 10.1038/s41593-022-01176-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 09/01/2022] [Indexed: 01/13/2023]
Abstract
The dentate gyrus (DG) gates neocortical information flow to the hippocampus. Intriguingly, the DG also produces adult-born dentate granule cells (abDGCs) throughout the lifespan, but their contribution to downstream firing dynamics remains unclear. Here, we show that abDGCs promote sparser hippocampal population spiking during mnemonic processing of novel stimuli. By combining triple-(DG-CA3-CA1) ensemble recordings and optogenetic interventions in behaving mice, we show that abDGCs constitute a subset of high-firing-rate neurons with enhanced activity responses to novelty and strong modulation by theta oscillations. Selectively activating abDGCs in their 4-7-week post-birth period increases sparsity of hippocampal population patterns, whereas suppressing abDGCs reduces this sparsity, increases principal cell firing rates and impairs novel object recognition with reduced dimensionality of the network firing structure, without affecting single-neuron spatial representations. We propose that adult-born granule cells transiently support sparser hippocampal population activity structure for higher-dimensional responses relevant to effective mnemonic information processing.
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20
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Kang YJ, Lee SH, Boychuk JA, Butler CR, Juras JA, Cloyd RA, Smith BN. Adult Born Dentate Granule Cell Mediated Upregulation of Feedback Inhibition in a Mouse Model of Traumatic Brain Injury. J Neurosci 2022; 42:7077-7093. [PMID: 36002261 PMCID: PMC9480876 DOI: 10.1523/jneurosci.2263-21.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 08/09/2022] [Accepted: 08/11/2022] [Indexed: 11/21/2022] Open
Abstract
Post-traumatic epilepsy (PTE) and behavioral comorbidities frequently develop after traumatic brain injury (TBI). Aberrant neurogenesis of dentate granule cells (DGCs) after TBI may contribute to the synaptic reorganization that occurs in PTE, but how neurogenesis at different times relative to the injury contributes to feedback inhibition and recurrent excitation in the dentate gyrus is unknown. Thus, we examined whether DGCs born at different postnatal ages differentially participate in feedback inhibition and recurrent excitation in the dentate gyrus using the controlled cortical impact (CCI) model of TBI. Both sexes of transgenic mice expressing channelrhodopsin2 (ChR2) in postnatally born DGCs were used for optogenetic activation of three DGC cohorts: postnatally early born DGCs, or those born just before or after CCI. We performed whole-cell patch-clamp recordings from ChR2-negative, mature DGCs and parvalbumin-expressing basket cells (PVBCs) in hippocampal slices to determine whether optogenetic activation of postnatally born DGCs increases feedback inhibition and/or recurrent excitation in mice 8-10 weeks after CCI and whether PVBCs are targets of ChR2-positive DGCs. In the dentate gyrus ipsilateral to CCI, activation of ChR2-expressing DGCs born before CCI produced increased feedback inhibition in ChR2-negative DGCs and increased excitation in PVBCs compared with those from sham controls. This upregulated feedback inhibition was less prominent in DGCs born early in life or after CCI. Surprisingly, ChR2-positive DGC activation rarely evoked recurrent excitation in mature DGCs from any cohort. These results support that DGC birth date-related increased feedback inhibition in of DGCs may contribute to altered excitability after TBI.SIGNIFICANCE STATEMENT Dentate granule cells (DGCs) control excitability of the dentate gyrus through synaptic interactions with inhibitory GABAergic interneurons. Persistent changes in DGC synaptic connectivity develop after traumatic brain injury, contributing to hyperexcitability in post-traumatic epilepsy (PTE). However, the impact of DGC neurogenesis on synaptic reorganization, especially on inhibitory circuits, after brain injury is not adequately described. Here, upregulation of feedback inhibition in mature DGCs from male and female mice was associated with increased excitation of parvalbumin-expressing basket cells by postnatally born DGCs, providing novel insights into underlying mechanisms of altered excitability after brain injury. A better understanding of these inhibitory circuit changes can help formulate hypotheses for development of novel, evidence-based treatments for post-traumatic epilepsy by targeting birth date-specific subsets of DGCs.
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Affiliation(s)
- Young-Jin Kang
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523
- Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - Sang-Hun Lee
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523
- Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
- Epilepsy Research Center, University of Kentucky, Lexington, Kentucky 40536
| | - Jeffery A Boychuk
- Epilepsy Research Center, University of Kentucky, Lexington, Kentucky 40536
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - Corwin R Butler
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - J Anna Juras
- Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - Ryan A Cloyd
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - Bret N Smith
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523
- Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
- Epilepsy Research Center, University of Kentucky, Lexington, Kentucky 40536
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536
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21
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Larivee R, Johnson N, Freedgood NR, Cameron HA, Schoenfeld TJ. Inhibition of Hippocampal Neurogenesis Starting in Adolescence Increases Anxiodepressive Behaviors Amid Stress. Front Behav Neurosci 2022; 16:940125. [PMID: 35864848 PMCID: PMC9294378 DOI: 10.3389/fnbeh.2022.940125] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 06/16/2022] [Indexed: 11/16/2022] Open
Abstract
Stressors during the adolescent period can affect development of the brain and have long-lasting impacts on behavior. Specifically, adolescent stress impairs hippocampal neurogenesis and can increase risk for anxiety, depression, and a dysregulated stress response in adulthood. In order to model the functional effects of reduced hippocampal neurogenesis during adolescence, a transgenic neurogenesis ablation rat model was used to suppress neurogenesis during the adolescent period and test anxiodepressive behaviors and stress physiology during adulthood. Wildtype and transgenic (TK) rats were given valganciclovir during the first two weeks of adolescence (4-6 weeks old) to knock down neurogenesis in TK rats. Starting in young adulthood (13 weeks old), blood was sampled for corticosterone at several time points following acute restraint stress to measure negative feedback of the stress response, and rats were tested on a battery of anxiodepressive tests at baseline and following acute restraint stress. Although TK rats had large reductions in both cell proliferation during adolescence, as measured by bromodeoxyuridine (BrdU), and ongoing neurogenesis in adulthood (by doublecortin), resulting in decreased volume of the dentate gyrus, negative feedback of the stress response following acute restraint was similar across all rats. Despite similar stress responses, TK rats showed higher anxiety-like behavior at baseline. In addition, only TK rats had increased depressive-like behavior when tested after acute stress. Together, these results suggest that long-term neurogenesis ablation starting in adolescence produces hippocampal atrophy and increases behavioral caution and despair amid stressful environments.
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Affiliation(s)
- Rachelle Larivee
- Department of Psychological Science and Neuroscience, Belmont University, Nashville, TN, United States
| | - Natalie Johnson
- Department of Psychological Science and Neuroscience, Belmont University, Nashville, TN, United States
| | - Natalie R. Freedgood
- Section on Neuroplasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Heather A. Cameron
- Section on Neuroplasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Timothy J. Schoenfeld
- Department of Psychological Science and Neuroscience, Belmont University, Nashville, TN, United States
- *Correspondence: Timothy J. Schoenfeld,
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22
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Anxiety and hippocampal neuronal activity: Relationship and potential mechanisms. COGNITIVE, AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2022; 22:431-449. [PMID: 34873665 DOI: 10.3758/s13415-021-00973-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/11/2021] [Indexed: 12/15/2022]
Abstract
The hippocampus has been implicated in modulating anxiety. It interacts with a variety of brain regions, both cortical and subcortical areas regulating emotion and stress responses, including prefrontal cortex, amygdala, hypothalamus, and the nucleus accumbens, to adjust anxiety levels in response to a variety of stressful conditions. Growing evidence indicates that anxiety is associated with increased neuronal excitability in the hippocampus, and alterations in local regulation of hippocampal excitability have been suggested to underlie behavioral disruptions characteristic of certain anxiety disorders. Furthermore, studies have shown that some anxiolytics can treat anxiety by altering the excitability and plasticity of hippocampal neurons. Hence, identifying cellular and molecular mechanisms and neural circuits that regulate hippocampal excitability in anxiety may be beneficial for developing targeted interventions for treatment of anxiety disorders particularly for the treatment-resistant cases. We first briefly review a role of the hippocampus in fear. We then review the evidence indicating a relationship between the hippocampal activity and fear/anxiety and discuss some possible mechanisms underlying stress-induced hippocampal excitability and anxiety-related behavior.
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23
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Dohm-Hansen S, Donoso F, Lucassen PJ, Clarke G, Nolan YM. The gut microbiome and adult hippocampal neurogenesis: A new focal point for epilepsy? Neurobiol Dis 2022; 170:105746. [DOI: 10.1016/j.nbd.2022.105746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 04/13/2022] [Accepted: 04/29/2022] [Indexed: 02/07/2023] Open
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24
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Jennen L, Mazereel V, Lecei A, Samaey C, Vancampfort D, van Winkel R. Exercise to spot the differences: a framework for the effect of exercise on hippocampal pattern separation in humans. Rev Neurosci 2022; 33:555-582. [PMID: 35172422 DOI: 10.1515/revneuro-2021-0156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/16/2022] [Indexed: 12/12/2022]
Abstract
Exercise has a beneficial effect on mental health and cognitive functioning, but the exact underlying mechanisms remain largely unknown. In this review, we focus on the effect of exercise on hippocampal pattern separation, which is a key component of episodic memory. Research has associated exercise with improvements in pattern separation. We propose an integrated framework mechanistically explaining this relationship. The framework is divided into three pathways, describing the pro-neuroplastic, anti-inflammatory and hormonal effects of exercise. The pathways are heavily intertwined and may result in functional and structural changes in the hippocampus. These changes can ultimately affect pattern separation through direct and indirect connections. The proposed framework might guide future research on the effect of exercise on pattern separation in the hippocampus.
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Affiliation(s)
- Lise Jennen
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium
| | - Victor Mazereel
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium.,University Psychiatric Center KU Leuven, Leuvensesteenweg 517, 3070 Leuven-Kortenberg, Belgium
| | - Aleksandra Lecei
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium
| | - Celine Samaey
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium
| | - Davy Vancampfort
- University Psychiatric Center KU Leuven, Leuvensesteenweg 517, 3070 Leuven-Kortenberg, Belgium.,KU Leuven Department of Rehabilitation Sciences, ON IV Herestraat 49, bus 1510, 3000, Leuven, Belgium
| | - Ruud van Winkel
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium.,University Psychiatric Center KU Leuven, Leuvensesteenweg 517, 3070 Leuven-Kortenberg, Belgium
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25
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Adult Hippocampal Neurogenesis in Alzheimer’s Disease: An Overview of Human and Animal Studies with Implications for Therapeutic Perspectives Aimed at Memory Recovery. Neural Plast 2022; 2022:9959044. [PMID: 35075360 PMCID: PMC8783751 DOI: 10.1155/2022/9959044] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/21/2021] [Accepted: 12/15/2021] [Indexed: 12/31/2022] Open
Abstract
The mammalian hippocampal dentate gyrus is a niche for adult neurogenesis from neural stem cells. Newborn neurons integrate into existing neuronal networks, where they play a key role in hippocampal functions, including learning and memory. In the ageing brain, neurogenic capability progressively declines while in parallel increases the risk for developing Alzheimer's disease (AD), the main neurodegenerative disorder associated with memory loss. Numerous studies have investigated whether impaired adult neurogenesis contributes to memory decline in AD. Here, we review the literature on adult hippocampal neurogenesis (AHN) and AD by focusing on both human and mouse model studies. First, we describe key steps of AHN, report recent evidence of this phenomenon in humans, and describe the specific contribution of newborn neurons to memory, as evinced by animal studies. Next, we review articles investigating AHN in AD patients and critically examine the discrepancies among different studies over the last two decades. Also, we summarize researches investigating AHN in AD mouse models, and from these studies, we extrapolate the contribution of molecular factors linking AD-related changes to impaired neurogenesis. Lastly, we examine animal studies that link impaired neurogenesis to specific memory dysfunctions in AD and review treatments that have the potential to rescue memory capacities in AD by stimulating AHN.
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26
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Surget A, Belzung C. Adult hippocampal neurogenesis shapes adaptation and improves stress response: a mechanistic and integrative perspective. Mol Psychiatry 2022; 27:403-421. [PMID: 33990771 PMCID: PMC8960391 DOI: 10.1038/s41380-021-01136-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 04/09/2021] [Accepted: 04/19/2021] [Indexed: 02/03/2023]
Abstract
Adult hippocampal neurogenesis (AHN) represents a remarkable form of neuroplasticity that has increasingly been linked to the stress response in recent years. However, the hippocampus does not itself support the expression of the different dimensions of the stress response. Moreover, the main hippocampal functions are essentially preserved under AHN depletion and adult-born immature neurons (abGNs) have no extrahippocampal projections, which questions the mechanisms by which abGNs influence functions supported by brain areas far from the hippocampus. Within this framework, we propose that through its computational influences AHN is pivotal in shaping adaption to environmental demands, underlying its role in stress response. The hippocampus with its high input convergence and output divergence represents a computational hub, ideally positioned in the brain (1) to detect cues and contexts linked to past, current and predicted stressful experiences, and (2) to supervise the expression of the stress response at the cognitive, affective, behavioral, and physiological levels. AHN appears to bias hippocampal computations toward enhanced conjunctive encoding and pattern separation, promoting contextual discrimination and cognitive flexibility, reducing proactive interference and generalization of stressful experiences to safe contexts. These effects result in gating downstream brain areas with more accurate and contextualized information, enabling the different dimensions of the stress response to be more appropriately set with specific contexts. Here, we first provide an integrative perspective of the functional involvement of AHN in the hippocampus and a phenomenological overview of the stress response. We then examine the mechanistic underpinning of the role of AHN in the stress response and describe its potential implications in the different dimensions accompanying this response.
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Affiliation(s)
- A Surget
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France.
| | - C Belzung
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France.
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27
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Kapri D, Fanibunda SE, Vaidya VA. Thyroid hormone regulation of adult hippocampal neurogenesis: Putative molecular and cellular mechanisms. VITAMINS AND HORMONES 2021; 118:1-33. [PMID: 35180924 DOI: 10.1016/bs.vh.2021.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Adult hippocampal neurogenesis is sensitive to perturbations in thyroid hormone signaling, with evidence supporting a key role for thyroid hormone and thyroid hormone receptors (TRs) in the regulation of postmitotic progenitor survival and neuronal differentiation. In this book chapter we summarize the current understanding of the effects of thyroid hormone signaling on adult hippocampal progenitor development, and also critically address the role of TRs in regulation of distinct aspects of stage-specific hippocampal progenitor progression. We highlight actions of thyroid hormone on thyroid hormone responsive target genes, and the implications for hippocampal progenitor regulation. Given the influence of thyroid hormone on both mitochondrial and lipid metabolism, we discuss a putative role for regulation of metabolism in the effects of thyroid hormone on adult hippocampal neurogenesis. Finally, we highlight specific ideas that require detailed experimental investigation, and the need for future studies to obtain a deeper mechanistic insight into the influence of thyroid hormone and TRs in the developmental progression of adult hippocampal progenitors.
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Affiliation(s)
- Darshana Kapri
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Sashaina E Fanibunda
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India; Medical Research Centre, Kasturba Health Society, Mumbai, India
| | - Vidita A Vaidya
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.
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28
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Ko SY, Frankland PW. Neurogenesis-dependent transformation of hippocampal engrams. Neurosci Lett 2021; 762:136176. [PMID: 34400284 DOI: 10.1016/j.neulet.2021.136176] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 07/29/2021] [Accepted: 08/11/2021] [Indexed: 11/29/2022]
Abstract
In humans and other mammals, memories of events are encoded by neuronal ensembles (or engrams) in the hippocampus. The mnemonic information stored in these engrams can then be used to guide future behavior, including prediction- and decision-making in dynamic environments. While some hippocampal engrams may be persistently stored, others are modified over time, suggesting that the represented memories may also be transformed. How might hippocampal engrams be modified through time? Adult hippocampal neurogenesis represents one process that continuously rewires hippocampal circuitry, presumably including stored hippocampal engrams. At intermediate stages, we propose that neurogenesis-mediated rewiring of hippocampal engram circuitry induces forgetting of specific stimulus attributes, and this less precise engram allows for generalization. At more advanced stages, we propose that neurogenesis-mediated rewiring of hippocampal engram circuitry leads to silencing of hippocampal engrams, rendering them no longer accessible by natural retrieval cues.
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Affiliation(s)
- Sangyoon Y Ko
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Temerty Centre for AI Research and Education in Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Paul W Frankland
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Psychology, University of Toronto, Toronto, ON M5S 3G3, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON M5S 1A8, Canada; Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, ON M5G 1M1, Canada.
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29
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Ceanga M, Dahab M, Witte OW, Keiner S. Adult Neurogenesis and Stroke: A Tale of Two Neurogenic Niches. Front Neurosci 2021; 15:700297. [PMID: 34447293 PMCID: PMC8382802 DOI: 10.3389/fnins.2021.700297] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 06/30/2021] [Indexed: 01/17/2023] Open
Abstract
In the aftermath of an acute stroke, numerous signaling cascades that reshape the brain both in the perilesional zone as well as in more distal regions are activated. Despite continuous improvement in the acute treatment of stroke and the sustained research efforts into the pathophysiology of stroke, we critically lag in our integrated understanding of the delayed and chronic responses to ischemic injury. As such, the beneficial or maladaptive effect of some stroke-induced cellular responses is unclear, restricting the advancement of therapeutic strategies to target long-term complications. A prominent delayed effect of stroke is the robust increase in adult neurogenesis, which raises hopes for a regenerative strategy to counter neurological deficits in stroke survivors. In the adult brain, two regions are known to generate new neurons from endogenous stem cells: the subventricular zone (SVZ) and the dentate subgranular zone (SGZ) of the hippocampus. While both niches respond with an increase in neurogenesis post-stroke, there are significant regional differences in the ensuing stages of survival, migration, and maturation, which may differently influence functional outcome. External interventions such as rehabilitative training add a further layer of complexity by independently modulating the process of adult neurogenesis. In this review we summarize the current knowledge regarding the effects of ischemic stroke on neurogenesis in the SVZ and in the SGZ, and the influence of exogenous stimuli such as motor activity or enriched environment (EE). In addition, we discuss the contribution of SVZ or SGZ post-stroke neurogenesis to sensory, motor and cognitive recovery.
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Affiliation(s)
- Mihai Ceanga
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
- Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Jena, Germany
| | - Mahmoud Dahab
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Otto W. Witte
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Silke Keiner
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
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30
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Zocher S, Overall RW, Berdugo-Vega G, Rund N, Karasinsky A, Adusumilli VS, Steinhauer C, Scheibenstock S, Händler K, Schultze JL, Calegari F, Kempermann G. De novo DNA methylation controls neuronal maturation during adult hippocampal neurogenesis. EMBO J 2021; 40:e107100. [PMID: 34337766 PMCID: PMC8441477 DOI: 10.15252/embj.2020107100] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 06/28/2021] [Accepted: 07/02/2021] [Indexed: 11/20/2022] Open
Abstract
Adult neurogenesis enables the life‐long addition of functional neurons to the hippocampus and is regulated by both cell‐intrinsic molecular programs and behavioral activity. De novo DNA methylation is crucial for embryonic brain development, but its role during adult hippocampal neurogenesis has remained unknown. Here, we show that de novo DNA methylation is critical for maturation and functional integration of adult‐born neurons in the mouse hippocampus. Bisulfite sequencing revealed that de novo DNA methyltransferases target neuronal enhancers and gene bodies during adult hippocampal neural stem cell differentiation, to establish neuronal methylomes and facilitate transcriptional up‐regulation of neuronal genes. Inducible deletion of both de novo DNA methyltransferases Dnmt3a and Dnmt3b in adult neural stem cells did not affect proliferation or fate specification, but specifically impaired dendritic outgrowth and synaptogenesis of newborn neurons, thereby hampering their functional maturation. Consequently, abolishing de novo DNA methylation modulated activation patterns in the hippocampal circuitry and caused specific deficits in hippocampus‐dependent learning and memory. Our results demonstrate that proper establishment of neuronal methylomes during adult neurogenesis is fundamental for hippocampal function.
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Affiliation(s)
- Sara Zocher
- German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany.,Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
| | - Rupert W Overall
- German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany.,Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
| | - Gabriel Berdugo-Vega
- Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
| | - Nicole Rund
- German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany.,Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
| | - Anne Karasinsky
- German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany.,Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
| | - Vijay S Adusumilli
- German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany.,Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
| | - Christina Steinhauer
- German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany.,Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
| | - Sina Scheibenstock
- German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany.,Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
| | - Kristian Händler
- PRECISE Platform for Single Cell Genomics and Epigenomics, German Center for Neurodegenerative Diseases, University of Bonn, Bonn, Germany
| | - Joachim L Schultze
- PRECISE Platform for Single Cell Genomics and Epigenomics, German Center for Neurodegenerative Diseases, University of Bonn, Bonn, Germany
| | - Federico Calegari
- Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
| | - Gerd Kempermann
- German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany.,Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Dresden, Germany
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31
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Johnston S, Parylak SL, Kim S, Mac N, Lim C, Gallina I, Bloyd C, Newberry A, Saavedra CD, Novak O, Gonçalves JT, Gage FH, Shtrahman M. AAV ablates neurogenesis in the adult murine hippocampus. eLife 2021; 10:e59291. [PMID: 34259630 PMCID: PMC8331179 DOI: 10.7554/elife.59291] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/13/2021] [Indexed: 12/14/2022] Open
Abstract
Recombinant adeno-associated virus (rAAV) has been widely used as a viral vector across mammalian biology and has been shown to be safe and effective in human gene therapy. We demonstrate that neural progenitor cells (NPCs) and immature dentate granule cells (DGCs) within the adult murine hippocampus are particularly sensitive to rAAV-induced cell death. Cell loss is dose dependent and nearly complete at experimentally relevant viral titers. rAAV-induced cell death is rapid and persistent, with loss of BrdU-labeled cells within 18 hr post-injection and no evidence of recovery of adult neurogenesis at 3 months post-injection. The remaining mature DGCs appear hyperactive 4 weeks post-injection based on immediate early gene expression, consistent with previous studies investigating the effects of attenuating adult neurogenesis. In vitro application of AAV or electroporation of AAV2 inverted terminal repeats (ITRs) is sufficient to induce cell death. Efficient transduction of the dentategyrus (DG)- without ablating adult neurogenesis- can be achieved by injection of rAAV2-retro serotyped virus into CA3. rAAV2-retro results in efficient retrograde labeling of mature DGCs and permits in vivo two-photon calcium imaging of dentate activity while leaving adult neurogenesis intact. These findings expand on recent reports implicating rAAV-linked toxicity in stem cells and other cell types and suggest that future work using rAAV as an experimental tool in the DG and as a gene therapy for diseases of the central nervous system should be carefully evaluated.
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Affiliation(s)
- Stephen Johnston
- Neurosciences Graduate Program, University of California, San DiegoLa JollaUnited States
- Laboratory of Genetics, Salk Institute for Biological StudiesLa JollaUnited States
| | - Sarah L Parylak
- Laboratory of Genetics, Salk Institute for Biological StudiesLa JollaUnited States
| | - Stacy Kim
- Laboratory of Genetics, Salk Institute for Biological StudiesLa JollaUnited States
- Department of Neurosciences, University of California, San DiegoLa JollaUnited States
| | - Nolan Mac
- Department of Biology, University of California, San DiegoLa JollaUnited States
| | - Christina Lim
- Laboratory of Genetics, Salk Institute for Biological StudiesLa JollaUnited States
| | - Iryna Gallina
- Laboratory of Genetics, Salk Institute for Biological StudiesLa JollaUnited States
| | - Cooper Bloyd
- Laboratory of Genetics, Salk Institute for Biological StudiesLa JollaUnited States
| | - Alexander Newberry
- Department of Physics, University of California, San DiegoLa JollaUnited States
| | - Christian D Saavedra
- Laboratory of Genetics, Salk Institute for Biological StudiesLa JollaUnited States
| | - Ondrej Novak
- Laboratory of Experimental Epileptology, Department of Physiology, Second Faculty of Medicine, Charles UniversityPragueUnited Kingdom
| | - J Tiago Gonçalves
- Ruth L. and David S. Gottesman Institute for Stem Cell Biology and Regenerative Medicine, Albert Einstein College of MedicineBronxUnited States
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of MedicineBronxUnited States
| | - Fred H Gage
- Laboratory of Genetics, Salk Institute for Biological StudiesLa JollaUnited States
| | - Matthew Shtrahman
- Department of Neurosciences, University of California, San DiegoLa JollaUnited States
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32
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Life and Death of Immature Neurons in the Juvenile and Adult Primate Amygdala. Int J Mol Sci 2021; 22:ijms22136691. [PMID: 34206571 PMCID: PMC8268704 DOI: 10.3390/ijms22136691] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/11/2021] [Accepted: 06/18/2021] [Indexed: 12/12/2022] Open
Abstract
In recent years, a large population of immature neurons has been documented in the paralaminar nucleus of the primate amygdala. A substantial fraction of these immature neurons differentiate into mature neurons during postnatal development or following selective lesion of the hippocampus. Notwithstanding a growing number of studies on the origin and fate of these immature neurons, fundamental questions about the life and death of these neurons remain. Here, we briefly summarize what is currently known about the immature neurons present in the primate ventral amygdala during development and in adulthood, as well as following selective hippocampal lesions. We provide evidence confirming that the distribution of immature neurons extends to the anterior portions of the entorhinal cortex and layer II of the perirhinal cortex. We also provide novel arguments derived from stereological estimates of the number of mature and immature neurons, which support the view that the migration of immature neurons from the lateral ventricle accompanies neuronal maturation in the primate amygdala at all ages. Finally, we propose and discuss the hypothesis that increased migration and maturation of neurons in the amygdala following hippocampal dysfunction may be linked to behavioral alterations associated with certain neurodevelopmental disorders.
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33
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Structural and Functional Modulation of Perineuronal Nets: In Search of Important Players with Highlight on Tenascins. Cells 2021; 10:cells10061345. [PMID: 34072323 PMCID: PMC8230358 DOI: 10.3390/cells10061345] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/18/2021] [Accepted: 05/26/2021] [Indexed: 12/30/2022] Open
Abstract
The extracellular matrix (ECM) of the brain plays a crucial role in providing optimal conditions for neuronal function. Interactions between neurons and a specialized form of ECM, perineuronal nets (PNN), are considered a key mechanism for the regulation of brain plasticity. Such an assembly of interconnected structural and regulatory molecules has a prominent role in the control of synaptic plasticity. In this review, we discuss novel ways of studying the interplay between PNN and its regulatory components, particularly tenascins, in the processes of synaptic plasticity, mechanotransduction, and neurogenesis. Since enhanced neuronal activity promotes PNN degradation, it is possible to study PNN remodeling as a dynamical change in the expression and organization of its constituents that is reflected in its ultrastructure. The discovery of these subtle modifications is enabled by the development of super-resolution microscopy and advanced methods of image analysis.
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34
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Sossin WS, Anadolu MN, Langille JJ. Neuroscience: A New Pathway to Make Us Smarter and Happier. Curr Biol 2021; 30:R1051-R1054. [PMID: 32961162 DOI: 10.1016/j.cub.2020.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Treatments that improve cognition and decrease depression converge on decreasing phosphorylation of eukaryotic elongation factor 2 (eEF2). This decrease is sufficient to lead to altered levels of proteins that cause an increase in new neurons, improved cognition and less depression.
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Affiliation(s)
- Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada.
| | - Mina N Anadolu
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
| | - Jesse J Langille
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
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35
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Planchez B, Lagunas N, Le Guisquet AM, Legrand M, Surget A, Hen R, Belzung C. Increasing Adult Hippocampal Neurogenesis Promotes Resilience in a Mouse Model of Depression. Cells 2021; 10:cells10050972. [PMID: 33919292 PMCID: PMC8143348 DOI: 10.3390/cells10050972] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/13/2021] [Accepted: 04/19/2021] [Indexed: 11/16/2022] Open
Abstract
Many studies evaluated the functional role of adult hippocampal neurogenesis (AHN) and its key role in cognitive functions and mood regulation. The effects of promoting AHN on the recovery of stress-induced symptoms have been well studied, but its involvement in stress resilience remains elusive. We used a mouse model enabling us to foster AHN before the exposure to unpredictable chronic mild stress (UCMS) to evaluate the potential protective effects of AHN on stress, assessing the depressive-like phenotype and executive functions. For this purpose, an inducible transgenic mouse model was used to delete the pro-apoptotic gene Bax from neural progenitors four weeks before UCMS, whereby increasing the survival of adult-generated neurons. Our results showed that UCMS elicited a depressive-like phenotype, highlighted by a deteriorated coat state, a higher immobility duration in the tail suspension test (TST), and a delayed reversal learning in a water maze procedure. Promoting AHN before UCMS was sufficient to prevent the development of stressed-induced behavioral changes in the TST and the water maze, reflecting an effect of AHN on stress resilience. Taken together, our data suggest that increasing AHN promotes stress resilience on some depressive-like symptoms but also in cognitive symptoms, which are often observed in MD.
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Affiliation(s)
- Barbara Planchez
- UMR 1253, iBrain, Université de Tours, Inserm, CEDEX 1, 37032 Tours, France; (B.P.); (N.L.); (A.-M.L.G.); (M.L.); (A.S.)
| | - Natalia Lagunas
- UMR 1253, iBrain, Université de Tours, Inserm, CEDEX 1, 37032 Tours, France; (B.P.); (N.L.); (A.-M.L.G.); (M.L.); (A.S.)
| | - Anne-Marie Le Guisquet
- UMR 1253, iBrain, Université de Tours, Inserm, CEDEX 1, 37032 Tours, France; (B.P.); (N.L.); (A.-M.L.G.); (M.L.); (A.S.)
| | - Marc Legrand
- UMR 1253, iBrain, Université de Tours, Inserm, CEDEX 1, 37032 Tours, France; (B.P.); (N.L.); (A.-M.L.G.); (M.L.); (A.S.)
| | - Alexandre Surget
- UMR 1253, iBrain, Université de Tours, Inserm, CEDEX 1, 37032 Tours, France; (B.P.); (N.L.); (A.-M.L.G.); (M.L.); (A.S.)
| | - René Hen
- Departments of Neuroscience, Psychiatry & Pharmacology, Columbia University, New York, NY 10027, USA;
- Division of Integrative Neuroscience, Department of Psychiatry, New York State Psychiatric Institute, New York, NY 10032, USA
- Kavli Institute for Brain Sciences, Columbia University, New York, NY 10027, USA
| | - Catherine Belzung
- UMR 1253, iBrain, Université de Tours, Inserm, CEDEX 1, 37032 Tours, France; (B.P.); (N.L.); (A.-M.L.G.); (M.L.); (A.S.)
- Correspondence:
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Gampierakis IA, Koutmani Y, Semitekolou M, Morianos I, Polissidis A, Katsouda A, Charalampopoulos I, Xanthou G, Gravanis A, Karalis KP. Hippocampal neural stem cells and microglia response to experimental inflammatory bowel disease (IBD). Mol Psychiatry 2021; 26:1248-1263. [PMID: 31969694 DOI: 10.1038/s41380-020-0651-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 11/26/2019] [Accepted: 11/26/2019] [Indexed: 12/20/2022]
Abstract
Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a disease associated with dysbiosis, resulting in compromised intestinal epithelial barrier and chronic mucosal inflammation. Patients with IBD present with increased incidence of psychiatric disorders and cognitive impairment. Hippocampus is a brain region where adult neurogenesis occurs with functional implications in mood control and cognition. Using a well-established model of experimental colitis based on the administration of dextran sodium sulfate (DSS) in the drinking water, we sought to characterize the short and long-term effects of colitis on neurogenesis and glia responses in the hippocampus. We show that acute DSS colitis enhanced neurogenesis but with deficits in cell cycle kinetics of proliferating progenitors in the hippocampus. Chronic DSS colitis was characterized by normal levels of neurogenesis but with deficits in the migration and integration of newborn neurons in the functional circuitry of the DG. Notably, we found that acute DSS colitis-induced enhanced infiltration of the hippocampus with macrophages and inflammatory myeloid cells from the periphery, along with elevated frequencies of inflammatory M1-like microglia and increased release of pro-inflammatory cytokines. In contrast, increased percentages of tissue-repairing M2-like microglia, along with elevated levels of the anti-inflammatory cytokine, IL-10 were observed in the hippocampus during chronic DSS colitis. These findings uncover key effects of acute and chronic experimental colitis on adult hippocampal neurogenesis and innate immune cell responses, highlighting the potential mechanisms underlying cognitive and mood dysfunction in patients with IBD.
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Affiliation(s)
- Ioannis-Alexandros Gampierakis
- Center for Experimental Surgery, Clinical and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Greece
| | - Yassemi Koutmani
- Center for Experimental Surgery, Clinical and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Maria Semitekolou
- Cellular Immunology Laboratory, Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Ioannis Morianos
- Cellular Immunology Laboratory, Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Alexia Polissidis
- Center for Experimental Surgery, Clinical and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Antonia Katsouda
- Center for Experimental Surgery, Clinical and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- School of Pharmacy, University of Athens, Athens, Greece
| | - Ioannis Charalampopoulos
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Greece
- Institute of Molecular Biology & Biotechnology (IMBB), Foundation of Research & Technology Hellas (FORTH), Heraklion, Greece
| | - Georgina Xanthou
- Cellular Immunology Laboratory, Center for Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Achille Gravanis
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Greece
- Institute of Molecular Biology & Biotechnology (IMBB), Foundation of Research & Technology Hellas (FORTH), Heraklion, Greece
| | - Katia P Karalis
- Center for Experimental Surgery, Clinical and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece.
- Emulate, Inc., 27 Drydock Avenue, Boston, MA, 02210, USA.
- Endocrine Division, Children's Hospital, Harvard Medical School, Boston, MA, USA.
- Institute for Fundamental Biomedical Research, Biomedical Science Research Centre "Alexander Fleming", Athens, Greece.
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Briones BA, Pisano TJ, Pitcher MN, Haye AE, Diethorn EJ, Engel EA, Cameron HA, Gould E. Adult-born granule cell mossy fibers preferentially target parvalbumin-positive interneurons surrounded by perineuronal nets. Hippocampus 2021; 31:375-388. [PMID: 33432721 PMCID: PMC8020456 DOI: 10.1002/hipo.23296] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 12/07/2020] [Accepted: 12/12/2020] [Indexed: 12/11/2022]
Abstract
Adult-born granule cells (abGCs) integrate into the hippocampus and form connections with dentate gyrus parvalbumin-positive (PV+) interneurons, a circuit important for modulating plasticity. Many of these interneurons are surrounded by perineuronal nets (PNNs), extracellular matrix structures known to participate in plasticity. We compared abGC projections to PV+ interneurons with negative-to-low intensity PNNs to those with high intensity PNNs using retroviral and 3R-Tau labeling in adult mice, and found that abGC mossy fibers and boutons are more frequently located near PV+ interneurons with high intensity PNNs. These results suggest that axons of new neurons preferentially stabilize near target cells with intense PNNs. Next, we asked whether the number of abGCs influences PNN formation around PV+ interneurons, and found that near complete ablation of abGCs produced a decrease in the intensity and number of PV+ neurons with PNNs, suggesting that new neuron innervation may enhance PNN formation. Experience-driven changes in adult neurogenesis did not produce consistent effects, perhaps due to widespread effects on plasticity. Our study identifies abGC projections to PV+ interneurons with PNNs, with more presumed abGC mossy fiber boutons found near the cell body of PV+ interneurons with strong PNNs.
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Affiliation(s)
- Brandy A. Briones
- Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey
- Department of Psychology, Princeton University, Princeton, New Jersey
| | - Thomas J. Pisano
- Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey
| | - Miah N. Pitcher
- Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey
| | - Amanda E. Haye
- Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey
- Department of Psychology, Princeton University, Princeton, New Jersey
| | - Emma J. Diethorn
- Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey
- Department of Psychology, Princeton University, Princeton, New Jersey
| | - Esteban A. Engel
- Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey
| | - Heather A. Cameron
- Section on Neuroplasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Elizabeth Gould
- Princeton Neuroscience Institute, Princeton University, Princeton, New Jersey
- Department of Psychology, Princeton University, Princeton, New Jersey
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38
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Huckleberry KA, Shansky RM. The unique plasticity of hippocampal adult-born neurons: Contributing to a heterogeneous dentate. Hippocampus 2021; 31:543-556. [PMID: 33638581 DOI: 10.1002/hipo.23318] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/15/2021] [Accepted: 02/09/2021] [Indexed: 12/14/2022]
Abstract
The dentate gyrus (DG) of the hippocampus is evolutionarily conserved as one of the few sites of adult neurogenesis in mammals. Although there is clear evidence that neurogenesis is necessary for healthy hippocampal function, whether adult-born neurons are simply integrated into existing hippocampal networks to serve a similar purpose to that of developmentally born neurons or whether they represent a discrete cell population with unique functions remains less clear. In this review, we consider evidence for discrete cellular, synaptic, and structural features of adult-born DG neurons, suggesting that neurogenesis contributes to the formation of a heterogeneous DG. We therefore propose that hippocampal neurogenesis creates a specialized neuronal subpopulation that may play a key role in hippocampal functions like episodic memory. We note critical gaps in this extensive body of work, including a general failure to include female animals in relevant research and a need for more precise consideration of intrahippocampal neuroanatomy.
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Affiliation(s)
- Kylie A Huckleberry
- Behavioral Neuroscience Program, Department of Psychology, Northeastern University, Boston, Massachusetts, USA
| | - Rebecca M Shansky
- Behavioral Neuroscience Program, Department of Psychology, Northeastern University, Boston, Massachusetts, USA
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Eliwa H, Brizard B, Le Guisquet AM, Hen R, Belzung C, Surget A. Adult neurogenesis augmentation attenuates anhedonia and HPA axis dysregulation in a mouse model of chronic stress and depression. Psychoneuroendocrinology 2021; 124:105097. [PMID: 33302237 PMCID: PMC8715720 DOI: 10.1016/j.psyneuen.2020.105097] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/06/2020] [Accepted: 11/26/2020] [Indexed: 11/26/2022]
Abstract
Major depressive disorder is a common debilitating mental health problem that represents one of the leading causes of disability. Up to date, the therapeutic targets and approaches are still limited. Adult hippocampal neurogenesis (AHN) has been proposed as a critical contributor to the pathophysiology and treatment of depression, altering the hippocampal control over stress response at network, neuroendocrine and behavioral levels. These findings together have suggested that manipulating AHN may be a promising therapeutic strategy for depression. To investigate this question, we assessed whether increasing adult neurogenesis would be sufficient to produce antidepressant-like effects at behavioral and neuroendocrine levels in a mouse model of depression; the unpredictable chronic mild stress (UCMS). For this purpose, we used a bi-transgenic mouse line (iBax) in which AHN increase was induced by deletion of the pro-apoptotic gene Bax from the neural progenitors following the tamoxifen-dependent action of CreERT2 recombinases. UCMS induced a syndrome that is reminiscent of depression-like states, including anhedonia (cookie test), physical changes (coat deterioration, reduced weight gain), anxiety-like behaviors (higher latency in the novelty-supressed feeding -NSF- test), passive stress-coping behaviors (immobility in the forced swim test -FST-) and a blunted hypothalamo-pituitary-adrenal (HPA) axis reactivity to acute stress in addition to AHN decrease. Tamoxifen injection reversed the AHN decrease as well as partly counteracted UCMS effects on the cookie test and HPA axis but not for the coat state, weight gain, NSF test and FST. Taken together, our results suggest that a strategy directing at increasing AHN may be able to alleviate some depression-related behavioral and neuroendocrine dimensions of UCMS, such as anhedonia and HPA axis reactivity deficits, but may be hardly sufficient to produce a complete recovery.
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Affiliation(s)
- Hoda Eliwa
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France; Department of Cell Biology, Medical Research Institute, Alexandria University, Egypt
| | - Bruno Brizard
- UMR 1253, iBrain, Université de Tours, Inserm, Tours, France
| | | | - René Hen
- Departments of Neuroscience, Psychiatry, & Pharmacology, Columbia University, New York, NY, USA; Division of Integrative Neuroscience, Department of Psychiatry, New York State Psychiatric Institute, New York, NY, USA; Kavli Institute for Brain Sciences, Columbia University, New York, NY, USA
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40
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Lensu S, Waselius T, Mäkinen E, Kettunen H, Virtanen A, Tiirola M, Penttonen M, Pekkala S, Nokia MS. Irradiation of the head reduces adult hippocampal neurogenesis and impairs spatial memory, but leaves overall health intact in rats. Eur J Neurosci 2021; 53:1885-1904. [PMID: 33382141 DOI: 10.1111/ejn.15102] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/21/2020] [Accepted: 12/28/2020] [Indexed: 12/19/2022]
Abstract
Treatment of brain cancer, glioma, can cause cognitive impairment as a side-effect, possibly because it disrupts the integrity of the hippocampus, a structure vital for normal memory. Radiotherapy is commonly used to treat glioma, but the effects of irradiation on the brain are still poorly understood, and other biological effects have not been extensively studied. Here, we exposed healthy adult male rats to moderate-dose irradiation of the head. We found no effect of irradiation on systemic inflammation, weight gain or gut microbiota diversity, although it increased the abundance of Bacteroidaceae family, namely Bacteroides genus in the gut microbiota. Irradiation had no effect on long-term potentiation in the CA3-CA1 synapse or endogenous hippocampal electrophysiology, but it did reduce adult hippocampal neurogenesis and impaired short-term spatial recognition memory. However, no overall cognitive impairment was observed. To summarize, our results suggest that in adult male rats head irradiation does not compromise health or cognition overall even though the number of new, adult-born hippocampal neurons is decreased. Thus, the sole effects of head irradiation on the body, brain and cognition might be less harmful than previously thought, and the cognitive decline experienced by cancer patients might originate from physiological and mental effects of the disease itself. Therefore, to increase the translational value of animal studies, the effects of irradiation should be studied together with cancer, in older animals, using varying irradiation protocols and doses.
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Affiliation(s)
- Sanna Lensu
- Faculty of Sport and Health Sciences, University of Jyvaskyla, Jyvaskyla, Finland.,Department of Psychology, University of Jyvaskyla, Jyvaskyla, Finland
| | - Tomi Waselius
- Department of Psychology, University of Jyvaskyla, Jyvaskyla, Finland
| | - Elina Mäkinen
- Faculty of Sport and Health Sciences, University of Jyvaskyla, Jyvaskyla, Finland
| | - Heikki Kettunen
- Department of Physics, University of Jyvaskyla, Jyvaskyla, Finland
| | - Ari Virtanen
- Department of Physics, University of Jyvaskyla, Jyvaskyla, Finland
| | - Marja Tiirola
- Department of Biological and Environmental Sciences, University of Jyvaskyla, Jyvaskyla, Finland
| | - Markku Penttonen
- Department of Psychology, University of Jyvaskyla, Jyvaskyla, Finland
| | - Satu Pekkala
- Faculty of Sport and Health Sciences, University of Jyvaskyla, Jyvaskyla, Finland
| | - Miriam S Nokia
- Department of Psychology, University of Jyvaskyla, Jyvaskyla, Finland
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41
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Clark LR, Yun S, Acquah NK, Kumar PL, Metheny HE, Paixao RCC, Cohen AS, Eisch AJ. Mild Traumatic Brain Injury Induces Transient, Sequential Increases in Proliferation, Neuroblasts/Immature Neurons, and Cell Survival: A Time Course Study in the Male Mouse Dentate Gyrus. Front Neurosci 2021; 14:612749. [PMID: 33488351 PMCID: PMC7817782 DOI: 10.3389/fnins.2020.612749] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/02/2020] [Indexed: 12/17/2022] Open
Abstract
Mild traumatic brain injuries (mTBIs) are prevalent worldwide. mTBIs can impair hippocampal-based functions such as memory and cause network hyperexcitability of the dentate gyrus (DG), a key entry point to hippocampal circuitry. One candidate for mediating mTBI-induced hippocampal cognitive and physiological dysfunction is injury-induced changes in the process of DG neurogenesis. There are conflicting results on how TBI impacts the process of DG neurogenesis; this is not surprising given that both the neurogenesis process and the post-injury period are dynamic, and that the quantification of neurogenesis varies widely in the literature. Even within the minority of TBI studies focusing specifically on mild injuries, there is disagreement about if and how mTBI changes the process of DG neurogenesis. Here we utilized a clinically relevant rodent model of mTBI (lateral fluid percussion injury, LFPI), gold-standard markers and quantification of the neurogenesis process, and three time points post-injury to generate a comprehensive picture of how mTBI affects adult hippocampal DG neurogenesis. Male C57BL/6J mice (6-8 weeks old) received either sham surgery or mTBI via LFPI. Proliferating cells, neuroblasts/immature neurons, and surviving cells were quantified via stereology in DG subregions (subgranular zone [SGZ], outer granule cell layer [oGCL], molecular layer, and hilus) at short-term (3 days post-injury, dpi), intermediate (7 dpi), and long-term (31 dpi) time points. The data show this model of mTBI induces transient, sequential increases in ipsilateral SGZ/GCL proliferating cells, neuroblasts/immature neurons, and surviving cells which is suggestive of mTBI-induced neurogenesis. In contrast to these ipsilateral hemisphere findings, measures in the contralateral hemisphere were not increased in key neurogenic DG subregions after LFPI. Our work in this mTBI model is in line with most literature on other and more severe models of TBI in showing TBI stimulates the process of DG neurogenesis. However, as our DG data in mTBI provide temporal, subregional, and neurogenesis-stage resolution, these data are important to consider in regard to the functional importance of TBI-induction of the neurogenesis process and future work assessing the potential of replacing and/or repairing DG neurons in the brain after TBI.
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Affiliation(s)
- Lyles R. Clark
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia (CHOP) Research Institute, Philadelphia, PA, United States
- Mahoney Institute for Neurosciences, Perelman School of Medicine, Philadelphia, PA, United States
| | - Sanghee Yun
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia (CHOP) Research Institute, Philadelphia, PA, United States
- Mahoney Institute for Neurosciences, Perelman School of Medicine, Philadelphia, PA, United States
| | - Nana K. Acquah
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia (CHOP) Research Institute, Philadelphia, PA, United States
- Biological Basis of Behavior Program, University of Pennsylvania, Philadelphia, PA, United States
| | - Priya L. Kumar
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia (CHOP) Research Institute, Philadelphia, PA, United States
- Biomechanical Engineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Hannah E. Metheny
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia (CHOP) Research Institute, Philadelphia, PA, United States
| | - Rikley C. C. Paixao
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia (CHOP) Research Institute, Philadelphia, PA, United States
| | - Akivas S. Cohen
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia (CHOP) Research Institute, Philadelphia, PA, United States
- Mahoney Institute for Neurosciences, Perelman School of Medicine, Philadelphia, PA, United States
| | - Amelia J. Eisch
- Department of Anesthesiology and Critical Care Medicine, The Children’s Hospital of Philadelphia (CHOP) Research Institute, Philadelphia, PA, United States
- Mahoney Institute for Neurosciences, Perelman School of Medicine, Philadelphia, PA, United States
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42
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Morales C, Morici JF, Espinosa N, Sacson A, Lara-Vasquez A, García-Pérez MA, Bekinschtein P, Weisstaub NV, Fuentealba P. Dentate Gyrus Somatostatin Cells are Required for Contextual Discrimination During Episodic Memory Encoding. Cereb Cortex 2021; 31:1046-1059. [PMID: 33026440 DOI: 10.1093/cercor/bhaa273] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 08/24/2020] [Accepted: 08/25/2020] [Indexed: 11/12/2022] Open
Abstract
Memory systems ought to store and discriminate representations of similar experiences in order to efficiently guide future decisions. This problem is solved by pattern separation, implemented in the dentate gyrus (DG) by granule cells to support episodic memory formation. Pattern separation is enabled by tonic inhibitory bombardment generated by multiple GABAergic cell populations that strictly maintain low activity levels in granule cells. Somatostatin-expressing cells are one of those interneuron populations, selectively targeting the distal dendrites of granule cells, where cortical multimodal information reaches the DG. Nonetheless, somatostatin cells have very low connection probability and synaptic efficacy with both granule cells and other interneuron types. Hence, the role of somatostatin cells in DG circuitry, particularly in the context of pattern separation, remains uncertain. Here, by using optogenetic stimulation and behavioral tasks in mice, we demonstrate that somatostatin cells are required for the acquisition of both contextual and spatial overlapping memories.
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Affiliation(s)
- Cristian Morales
- Departamento de Psiquiatria, Centro Interdisciplinario de Neurociencia, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile
| | - Juan Facundo Morici
- Instituto de Neurociencia Cognitiva y Traslacional, Instituto de Neurologia Cognitiva, Consejo Nacional de Investigaciones Cientificas y Tecnicas Fundacion INECO, Universidad Favaloro, 1078 Buenos Aires, Argentina
| | - Nelson Espinosa
- Departamento de Psiquiatria, Centro Interdisciplinario de Neurociencia, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile
| | - Agostina Sacson
- Instituto de Neurociencia Cognitiva y Traslacional, Instituto de Neurologia Cognitiva, Consejo Nacional de Investigaciones Cientificas y Tecnicas Fundacion INECO, Universidad Favaloro, 1078 Buenos Aires, Argentina
| | - Ariel Lara-Vasquez
- Departamento de Psiquiatria, Centro Interdisciplinario de Neurociencia, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile
| | - M A García-Pérez
- Departamento de Psiquiatria, Centro Interdisciplinario de Neurociencia, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile
| | - Pedro Bekinschtein
- Instituto de Neurociencia Cognitiva y Traslacional, Instituto de Neurologia Cognitiva, Consejo Nacional de Investigaciones Cientificas y Tecnicas Fundacion INECO, Universidad Favaloro, 1078 Buenos Aires, Argentina
| | - Noelia V Weisstaub
- Instituto de Neurociencia Cognitiva y Traslacional, Instituto de Neurologia Cognitiva, Consejo Nacional de Investigaciones Cientificas y Tecnicas Fundacion INECO, Universidad Favaloro, 1078 Buenos Aires, Argentina
| | - Pablo Fuentealba
- Departamento de Psiquiatria, Centro Interdisciplinario de Neurociencia, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile.,Centro de Investigacion en Nanotecnologia y Materiales Avanzados, Pontificia Universidad Catolica de Chile, Santiago 7820436, Chile
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Adult-Born Neurons in the Hippocampus Are Essential for Social Memory Maintenance. eNeuro 2020; 7:ENEURO.0182-20.2020. [PMID: 33060182 PMCID: PMC7768285 DOI: 10.1523/eneuro.0182-20.2020] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/18/2020] [Accepted: 09/30/2020] [Indexed: 01/02/2023] Open
Abstract
Throughout adulthood, the dentate gyrus continues to produce new granule cells, which integrate into the hippocampal circuitry. New neurons have been linked to several known functions of the hippocampus, including learning and memory, anxiety and stress regulation, and social behavior. We explored whether transgenic reduction of adult-born neurons in mice would impair social memory and the formation of social dominance hierarchies. We used a conditional transgenic mouse strain [thymidine kinase (TK) mice] that selectively reduces adult neurogenesis by treatment with the antiviral drug valganciclovir (VGCV). TK mice treated with VGCV were unable to recognize conspecifics as familiar 24 h after initial exposure. We then explored whether reducing new neurons completely impaired their ability to acquire or retrieve a social memory and found that TK mice treated with VGCV were able to perform at control levels when the time between exposure (acquisition) and reexposure (retrieval) was brief. We next explored whether adult-born neurons are involved in dominance hierarchy formation by analyzing their home cage behavior as well as their performance in the tube test, a social hierarchy test, and did not find any consistent alterations in behavior between control and TK mice treated with VGCV. These data suggest that adult neurogenesis is essential for social memory maintenance, but not for acquisition nor retrieval over a short time frame, with no effect on social dominance hierarchy. Future work is needed to explore whether the influence of new neurons on social memory is mediated through connections with the CA2, an area involved in social recognition.
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44
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Changes in Hippocampal Plasticity in Depression and Therapeutic Approaches Influencing These Changes. Neural Plast 2020; 2020:8861903. [PMID: 33293948 PMCID: PMC7718046 DOI: 10.1155/2020/8861903] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/30/2020] [Accepted: 11/11/2020] [Indexed: 02/06/2023] Open
Abstract
Depression is a common neurological disease that seriously affects human health. There are many hypotheses about the pathogenesis of depression, and the most widely recognized and applied is the monoamine hypothesis. However, no hypothesis can fully explain the pathogenesis of depression. At present, the brain-derived neurotrophic factor (BDNF) and neurogenesis hypotheses have highlighted the important role of plasticity in depression. The plasticity of neurons and glial cells plays a vital role in the transmission and integration of signals in the central nervous system. Plasticity is the adaptive change in the nervous system in response to changes in external signals. The hippocampus is an important anatomical area associated with depression. Studies have shown that some antidepressants can treat depression by changing the plasticity of the hippocampus. Furthermore, caloric restriction has also been shown to affect antidepressant and hippocampal plasticity changes. In this review, we summarize the latest research, focusing on changes in the plasticity of hippocampal neurons and glial cells in depression and the role of BDNF in the changes in hippocampal plasticity in depression, as well as caloric restriction and mitochondrial plasticity. This review may contribute to the development of antidepressant drugs and elucidating the mechanism of depression.
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45
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Traumatic brain injury modifies synaptic plasticity in newly-generated granule cells of the adult hippocampus. Exp Neurol 2020; 336:113527. [PMID: 33188818 DOI: 10.1016/j.expneurol.2020.113527] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/30/2020] [Accepted: 10/27/2020] [Indexed: 01/11/2023]
Abstract
The hippocampus is vulnerable to traumatic brain injury (TBI), and hippocampal damage is associated with cognitive deficits that are often the hallmark of TBI. Recent studies have found that TBI induces enhanced neurogenesis in the dentate gyrus (DG) of the hippocampus, and this cellular response is related to innate cognitive recovery. However, cellular mechanisms of the role of DG neurogenesis in post-TBI recovery remain unclear. This study investigated changes in long-term potentiation (LTP) within the DG in relation to TBI-induced neurogenesis. Adult male rats received a moderate TBI or sham injury and were sacrificed for brain slice recordings at 30 or 60 days post-injury. Recordings were taken from the medial perforant path input to DG granule cells in the presence or absence of the GABAergic antagonist picrotoxin, reflecting activity of either all DG granule cells or predominately newborn granule cells, respectively. Measurements of LTP observed in the total granule cell population (with picrotoxin) showed a prolonged impairment which worsened between 30 and 60 days post-TBI. Under conditions which predominantly reflected the LTP elicited in newly born granule cells (no picrotoxin), a strikingly different pattern of post-TBI changes was observed, with a time-dependent cycle of functional impairment and recovery. At 30 days after injury this cell population showed little or no LTP, but by 60 days the capacity for LTP of the newly born granule cells was no different from that of sham controls. The time-frame of LTP improvements in the newborn cell population, comparable to that of behavioral recovery reported previously, suggests the unique functional properties of newborn granule cells enable them to contribute to restorative change following brain injury.
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Yohn CN, Dieterich A, Maita I, Bazer AS, Diethorn E, Ma D, Gergues MM, Hu P, Samuels BA. Behavioral response to fluoxetine in both female and male mice is modulated by dentate gyrus granule cell activity. Neurobiol Stress 2020; 13:100257. [PMID: 33344712 PMCID: PMC7739193 DOI: 10.1016/j.ynstr.2020.100257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/08/2020] [Accepted: 10/11/2020] [Indexed: 12/28/2022] Open
Abstract
Depression is a complex psychiatric disorder that is a major burden on society, with only ~33% of depressed patients attaining remission upon initial monotherapy with a selective serotonin reuptake inhibitor (SSRI). In preclinical studies using rodents, chronic stress paradigms, such as chronic corticosterone and social instability stress, are used to induce avoidance behaviors associated with negative affective states. Chronic fluoxetine (FLX; an SSRI) treatment reverses these chronic stress-induced behavioral changes in some, but not all mice, permitting stratification of mice into behavioral responders and non-responders to FLX. We previously reported that 5-HT1A receptors, which are Gi-coupled inhibitory receptors, on mature granule cells (GCs) in the dentate gyrus (DG) are necessary and sufficient for the behavioral, neurogenic, and neuroendocrine response to chronic SSRI treatment. Since inhibition of mature DG GCs through cell autonomous Gi-coupled receptors is critical for mounting an antidepressant response, we assessed the relationship between behavioral response to FLX and DG GC activation in FLX responders, non-responders, and stress controls in both male and female mice. Intriguingly, using disparate stress paradigms, we found that male and female behavioral FLX responders show decreased DG GC activation (as measured by cFos immunostaining) relative to non-responders and stress controls. We then show in both sexes that chronic inhibition of ventral DG GCs (through usage of Gi-DREADDs) results in a decrease in maladaptive avoidance behaviors, while ventral DG GCs stimulation with Gq-DREADDs increases maladaptive behaviors. Finally, we were able to bidirectionally control the behavioral response to FLX through modulation of DG GCs. Chronic inhibition of ventral DG GCs with Gi-DREADDs converted FLX non-responders into responders, while activation of ventral DG GCs with Gq-DREADDs converted FLX responders into non-responders. This study illustrates ventral DG GC activity is a major modulator of the behavioral response to FLX in both male and female mice.
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Affiliation(s)
| | - Andrew Dieterich
- Neuroscience Graduate Program, Rutgers, The State University of New Jersey, 152 Frelinghuysen Rd, Piscataway, NJ, USA
| | - Isabella Maita
- Neuroscience Graduate Program, Rutgers, The State University of New Jersey, 152 Frelinghuysen Rd, Piscataway, NJ, USA
| | - Allyson S. Bazer
- Behavioral & Systems Neuroscience, Department of Psychology, USA
| | - Emma Diethorn
- Behavioral & Systems Neuroscience, Department of Psychology, USA
| | - Debbie Ma
- Behavioral & Systems Neuroscience, Department of Psychology, USA
| | - Mark M. Gergues
- Behavioral & Systems Neuroscience, Department of Psychology, USA
| | - Pu Hu
- Behavioral & Systems Neuroscience, Department of Psychology, USA
| | - Benjamin A. Samuels
- Behavioral & Systems Neuroscience, Department of Psychology, USA
- Neuroscience Graduate Program, Rutgers, The State University of New Jersey, 152 Frelinghuysen Rd, Piscataway, NJ, USA
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47
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Xia Y, Zhang Z, Lin W, Yan J, Zhu C, Yin D, He S, Su Y, Xu N, Caldwell RW, Yao L, Chen Y. Modulating microglia activation prevents maternal immune activation induced schizophrenia-relevant behavior phenotypes via arginase 1 in the dentate gyrus. Neuropsychopharmacology 2020; 45:1896-1908. [PMID: 32599605 PMCID: PMC7608378 DOI: 10.1038/s41386-020-0743-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 06/10/2020] [Accepted: 06/16/2020] [Indexed: 12/31/2022]
Abstract
Prenatal infection during pregnancy increases the risk for developing neuropsychiatric disorders such as schizophrenia. This is linked to an inflammatory microglial phenotype in the offspring induced by maternal immune activation (MIA). Microglia are crucial for brain development and maintenance of neuronal niches, however, whether and how their activation is involved in the regulation of neurodevelopment remains unclear. Here, we used a MIA rodent model in which polyinosinic: polycytidylic acid (poly (I:C)) was injected into pregnant mice. We found fewer parvalbumin positive (PV+) cells and impaired GABAergic transmission in the dentate gyrus (DG), accompanied by schizophrenia-like behavior in the adult offspring. Minocycline, a potent inhibitor of microglia activation, successfully prevented the above-mentioned deficits in the offspring. Furthermore, by using microglia-specific arginase 1 (Arg1) ablation as well as overexpression in DG, we identified a critical role of Arg1 in microglia activation to protect against poly (I:C) imparted neuropathology and altered behavior in offspring. Taken together, our results highlight that Arg1-mediated alternative activation of microglia are potential therapeutic targets for psychiatric disorders induced by MIA.
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Affiliation(s)
- Yucen Xia
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, 510006 China
| | - Zhiqing Zhang
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, 510006 China
| | - Weipeng Lin
- grid.22069.3f0000 0004 0369 6365Key Laboratory of Brain Functional Genomics, Ministry of Education and Shanghai, School of Life Science, East China Normal University, Shanghai, 200062 China
| | - Jinglan Yan
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, 510006 China
| | - Chuan’an Zhu
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, 510006 China
| | - Dongmin Yin
- grid.22069.3f0000 0004 0369 6365Key Laboratory of Brain Functional Genomics, Ministry of Education and Shanghai, School of Life Science, East China Normal University, Shanghai, 200062 China
| | - Su He
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, 510006 China
| | - Yang Su
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, 510006 China
| | - Nenggui Xu
- grid.411866.c0000 0000 8848 7685South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, 510006 China
| | - Robert William Caldwell
- grid.410427.40000 0001 2284 9329Department of Pharmacology and Toxicology, Augusta University, Augusta, GA 30912 USA
| | - Lin Yao
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China. .,School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China.
| | - Yongjun Chen
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China. .,Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong-Macao Greater Bay Area, Guangzhou, 510515, China. .,Guangdong Province Key Laboratory of Psychiatric Disorders, Southern Medical University, Guangzhou, 510515, China.
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48
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Besnard A, Sahay A. Enhancing adult neurogenesis promotes contextual fear memory discrimination and activation of hippocampal-dorsolateral septal circuits. Behav Brain Res 2020; 399:112917. [PMID: 32949641 DOI: 10.1016/j.bbr.2020.112917] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/01/2020] [Accepted: 09/09/2020] [Indexed: 12/21/2022]
Abstract
Hippocampal circuitry is continuously modified by integration of adult-born dentate granule cells (DGCs). Prior work has shown that enhancing adult hippocampal neurogenesis decreases interference or overlap or conflict between ensembles of similar contexts and promotes discrimination of a shock-associated context from a similar, neutral context. However, the impact of enhanced integration of adult-born neurons on hippocampal network activity or downstream circuits such as the dorsolateral septum that mediate defensive behavioral responses is poorly understood. Here, we first replicated our finding that genetic expansion of the population of adult-born dentate granule cells (8 weeks and younger) promotes contextual fear discrimination. We found that enhanced contextual fear discrimination is associated with greater c-Fos expression in discrete hippocampal subfields along the proximo-distal and dorsoventral axis. Examination of the dorsolateral septum revealed an increase in activation of somatostatin expressing neurons consistent with recent characterization of these cells as calibrators of defensive behavior. Together, these findings begin to shed light on how genetically enhancing adult hippocampal neurogenesis affects activity of hippocampal-dorsolateral septal circuits.
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Affiliation(s)
- Antoine Besnard
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, 02114, USA; Harvard Stem Cell Institute, Cambridge, MA, 02138, USA; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Amar Sahay
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, 02114, USA; Harvard Stem Cell Institute, Cambridge, MA, 02138, USA; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA; BROAD Institute of Harvard and MIT, Cambridge, MA, 02142, USA.
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49
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Taha E, Patil S, Barrera I, Panov J, Khamaisy M, Proud CG, Bramham CR, Rosenblum K. eEF2/eEF2K Pathway in the Mature Dentate Gyrus Determines Neurogenesis Level and Cognition. Curr Biol 2020; 30:3507-3521.e7. [PMID: 32707059 DOI: 10.1016/j.cub.2020.06.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 05/08/2020] [Accepted: 06/18/2020] [Indexed: 12/13/2022]
Abstract
Levels of adult neurogenesis in the dentate gyrus (DG) of the hippocampus are correlated with unique cognitive functions. However, the molecular pathways controlling it are poorly understood. Here, we found that the known physiological ways to enhance neurogenesis converged on the eEF2/eEF2K pathway via AMPK in the DG. Enhancing the elongation phase of mRNA translation in eEF2K-knockout (eEF2K-KO) mice induced the expression of neurogenesis-related proteins in the hippocampus. We thus tested the hypothesis that inducing eEF2K-KO in mature neurons of the DG controls neurogenesis. Indeed, both general eEF2K-KO and targeted KO in DG excitatory mature neurons resulted in enhanced neurogenesis levels and upregulation of neurogenesis-related proteins. Increased neurogenesis was correlated with enhanced performance in DG-dependent learning. Moreover, general and local eEF2K-KO in old mice rejuvenated the DG, paving the way for better mechanistic understanding of how neurogenesis is controlled in the mature DG and possible treatments for incurable aging-associated diseases.
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Affiliation(s)
- Elham Taha
- Sagol Department of Neurobiology, 199 Aba Khoushy Avenue Mount Carmel, University of Haifa, 3498838 Haifa, Israel
| | - Sudarshan Patil
- Department of Biomedicine and KG Jebsen Centre for Research on Neuropsychiatric Disorders, Jonas Lies vei 91, University of Bergen, 5009 Bergen, Norway
| | - Iliana Barrera
- Sagol Department of Neurobiology, 199 Aba Khoushy Avenue Mount Carmel, University of Haifa, 3498838 Haifa, Israel
| | - Julia Panov
- Sagol Department of Neurobiology, 199 Aba Khoushy Avenue Mount Carmel, University of Haifa, 3498838 Haifa, Israel
| | - Mohammad Khamaisy
- Sagol Department of Neurobiology, 199 Aba Khoushy Avenue Mount Carmel, University of Haifa, 3498838 Haifa, Israel
| | - Christopher G Proud
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia; Hopwood Centre for Neurobiology, Lifelong Health, South Australian Health and Medical Research Institute, PO Box 11060, 5001 Adelaide, SA, Australia
| | - Clive R Bramham
- Department of Biomedicine and KG Jebsen Centre for Research on Neuropsychiatric Disorders, Jonas Lies vei 91, University of Bergen, 5009 Bergen, Norway
| | - Kobi Rosenblum
- Sagol Department of Neurobiology, 199 Aba Khoushy Avenue Mount Carmel, University of Haifa, 3498838 Haifa, Israel; Center for Gene Manipulation in the Brain, 199 Aba Khoushy Avenue Mount Carmel, University of Haifa, 3498838 Haifa, Israel.
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50
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Abstract
In the adult mammalian hippocampus, new neurons arise from stem and progenitor cell division, in a process known as adult neurogenesis. Adult-generated neurons are sensitive to experience and may participate in hippocampal functions, including learning and memory, anxiety and stress regulation, and social behavior. Increasing evidence emphasizes the importance of new neuron connectivity within hippocampal circuitry for understanding the impact of adult neurogenesis on brain function. In this Review, we discuss how the functional consequences of new neurons arise from the collective interactions of presynaptic and postsynaptic neurons, glial cells, and the extracellular matrix, which together form the "tetrapartite synapse."
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Affiliation(s)
- Elise C Cope
- Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, NJ 08544, USA
| | - Elizabeth Gould
- Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, NJ 08544, USA.
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