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Mortessagne P, Cartier E, Balia M, Fèvre M, Corailler F, Herry C, Abrous DN, Battefeld A, Pacary E. Genetic labeling of embryonically-born dentate granule neurons in young mice using the Penk Cre mouse line. Sci Rep 2024; 14:5022. [PMID: 38424161 PMCID: PMC10904803 DOI: 10.1038/s41598-024-55299-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/22/2024] [Indexed: 03/02/2024] Open
Abstract
The dentate gyrus (DG) of the hippocampus is a mosaic of dentate granule neurons (DGNs) accumulated throughout life. While many studies focused on the morpho-functional properties of adult-born DGNs, much less is known about DGNs generated during development, and in particular those born during embryogenesis. One of the main reasons for this gap is the lack of methods available to specifically label and manipulate embryonically-born DGNs. Here, we have assessed the relevance of the PenkCre mouse line as a genetic model to target this embryonically-born population. In young animals, PenkCre expression allows to tag neurons in the DG with positional, morphological and electrophysiological properties characteristic of DGNs born during the embryonic period. In addition, PenkCre+ cells in the DG are distributed in both blades along the entire septo-temporal axis. This model thus offers new possibilities to explore the functions of this underexplored population of embryonically-born DGNs.
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Affiliation(s)
- Pierre Mortessagne
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France
| | - Estelle Cartier
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France
| | - Maddalena Balia
- Univ. Bordeaux, CNRS, IMN, UMR 5293, 33000, Bordeaux, France
| | - Murielle Fèvre
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France
| | - Fiona Corailler
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France
| | - Cyril Herry
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France
| | - Djoher Nora Abrous
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France.
| | - Arne Battefeld
- Univ. Bordeaux, CNRS, IMN, UMR 5293, 33000, Bordeaux, France
| | - Emilie Pacary
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, 33000, Bordeaux, France.
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2
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Lods M, Mortessagne P, Pacary E, Terral G, Farrugia F, Mazier W, Masachs N, Charrier V, Cota D, Ferreira G, Abrous DN, Tronel S. Chemogenetic stimulation of adult neurogenesis, and not neonatal neurogenesis, is sufficient to improve long-term memory accuracy. Prog Neurobiol 2022; 219:102364. [DOI: 10.1016/j.pneurobio.2022.102364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 09/21/2022] [Accepted: 10/06/2022] [Indexed: 12/05/2022]
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3
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Koehl M, Ladevèze E, Montcouquiol M, Abrous DN. Vangl2, a Core Component of the WNT/PCP Pathway, Regulates Adult Hippocampal Neurogenesis and Age-Related Decline in Cognitive Flexibility. Front Aging Neurosci 2022; 14:844255. [PMID: 35370613 PMCID: PMC8965557 DOI: 10.3389/fnagi.2022.844255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 02/01/2022] [Indexed: 11/13/2022] Open
Abstract
Decline in episodic memory is one of the hallmarks of aging and represents one of the most important health problems facing Western societies. A key structure in episodic memory is the hippocampal formation and the dentate gyrus in particular, as the continuous production of new dentate granule neurons in this brain region was found to play a crucial role in memory and age-related decline in memory. As such, understanding the molecular processes that regulate the relationship between adult neurogenesis and aging of memory function holds great therapeutic potential. Recently, we found that Vang-Gogh like 2 (Vangl2), a core component of the Planar Cell Polarity (PCP) signaling pathway, is enriched in the dentate gyrus of adult mice. In this context, we sought to evaluate the involvement of this member of the Wnt/PCP pathway in both adult neurogenesis and memory abilities in adult and middle-aged mice. Using a heterozygous mouse model carrying a dominant-negative mutation in the Vangl2 gene, called Looptail (Vangl2Lp), we show that alteration in Vangl2 expression decreases the survival of adult-born granule cells and advances the onset of a decrease in cognitive flexibility. The inability of mutant mice to erase old irrelevant information to the benefit of new relevant ones highlights a key role of Vangl2 in interference-based forgetting. Taken together, our findings show that Vangl2 activity may constitute an interesting target to prevent age-related decline in hippocampal plasticity and memory.
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Affiliation(s)
- Muriel Koehl
- Univ. Bordeaux, INSERM, Magendie, U1215, Neurogenesis and Pathophysiology group, Bordeaux, France
- *Correspondence: Muriel Koehl
| | - Elodie Ladevèze
- Univ. Bordeaux, INSERM, Magendie, U1215, Neurogenesis and Pathophysiology group, Bordeaux, France
| | - Mireille Montcouquiol
- Univ. Bordeaux, INSERM, Magendie, U1215, Planar Polarity and Plasticity Group, Bordeaux, France
| | - Djoher Nora Abrous
- Univ. Bordeaux, INSERM, Magendie, U1215, Neurogenesis and Pathophysiology group, Bordeaux, France
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4
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Abrous DN, Koehl M, Lemoine M. A Baldwin interpretation of adult hippocampal neurogenesis: from functional relevance to physiopathology. Mol Psychiatry 2022; 27:383-402. [PMID: 34103674 PMCID: PMC8960398 DOI: 10.1038/s41380-021-01172-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 05/03/2021] [Accepted: 05/12/2021] [Indexed: 02/05/2023]
Abstract
Hippocampal adult neurogenesis has been associated to many cognitive, emotional, and behavioral functions and dysfunctions, and its status as a selected effect or an "appendix of the brain" has been debated. In this review, we propose to understand hippocampal neurogenesis as the process underlying the "Baldwin effect", a particular situation in evolution where fitness does not rely on the natural selection of genetic traits, but on "ontogenetic adaptation" to a changing environment. This supports the view that a strong distinction between developmental and adult hippocampal neurogenesis is made. We propose that their functions are the constitution and the lifelong adaptation, respectively, of a basic repertoire of cognitive and emotional behaviors. This lifelong adaptation occurs through new forms of binding, i.e., association or dissociation of more basic elements. This distinction further suggests that a difference is made between developmental vulnerability (or resilience), stemming from dysfunctional (or highly functional) developmental hippocampal neurogenesis, and adult vulnerability (or resilience), stemming from dysfunctional (or highly functional) adult hippocampal neurogenesis. According to this hypothesis, developmental and adult vulnerability are distinct risk factors for various mental disorders in adults. This framework suggests new avenues for research on hippocampal neurogenesis and its implication in mental disorders.
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Affiliation(s)
- Djoher Nora Abrous
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, Neurogenesis and Pathophysiology group, F-33000, Bordeaux, France.
| | - Muriel Koehl
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, Neurogenesis and Pathophysiology group, F-33000 Bordeaux, France
| | - Maël Lemoine
- grid.412041.20000 0001 2106 639XUniversity Bordeaux, CNRS, ImmunoConcEpT, UMR 5164, Bordeaux, France
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5
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Lods M, Pacary E, Mazier W, Farrugia F, Mortessagne P, Masachs N, Charrier V, Massa F, Cota D, Ferreira G, Abrous DN, Tronel S. Adult-born neurons immature during learning are necessary for remote memory reconsolidation in rats. Nat Commun 2021; 12:1778. [PMID: 33741954 PMCID: PMC7979763 DOI: 10.1038/s41467-021-22069-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 02/25/2021] [Indexed: 01/09/2023] Open
Abstract
Memory reconsolidation, the process by which memories are again stabilized after being reactivated, has strengthened the idea that memory stabilization is a highly plastic process. To date, the molecular and cellular bases of reconsolidation have been extensively investigated particularly within the hippocampus. However, the role of adult neurogenesis in memory reconsolidation is unclear. Here, we combined functional imaging, retroviral and chemogenetic approaches in rats to tag and manipulate different populations of rat adult-born neurons. We find that both mature and immature adult-born neurons are activated by remote memory retrieval. However, only specific silencing of the adult-born neurons immature during learning impairs remote memory retrieval-induced reconsolidation. Hence, our findings show that adult-born neurons immature during learning are required for the maintenance and update of remote memory reconsolidation.
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Affiliation(s)
- Marie Lods
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Emilie Pacary
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Wilfrid Mazier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Fanny Farrugia
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Pierre Mortessagne
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Nuria Masachs
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Vanessa Charrier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Federico Massa
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Daniela Cota
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Guillaume Ferreira
- INRA, Bordeaux INP, Nutrition and Integrative Neurobiology, UMR 1286, Bordeaux Cedex, France
| | - Djoher Nora Abrous
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France.
| | - Sophie Tronel
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France.
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6
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Kerloch T, Farrugia F, Bouit L, Maître M, Terral G, Koehl M, Mortessagne P, Heng JIT, Blanchard M, Doat H, Leste-Lasserre T, Goron A, Gonzales D, Perrais D, Guillemot F, Abrous DN, Pacary E. The atypical Rho GTPase Rnd2 is critical for dentate granule neuron development and anxiety-like behavior during adult but not neonatal neurogenesis. Mol Psychiatry 2021; 26:7280-7295. [PMID: 34561615 PMCID: PMC8872985 DOI: 10.1038/s41380-021-01301-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/06/2021] [Accepted: 09/08/2021] [Indexed: 02/08/2023]
Abstract
Despite the central role of Rho GTPases in neuronal development, their functions in adult hippocampal neurogenesis remain poorly explored. Here, by using a retrovirus-based loss-of-function approach in vivo, we show that the atypical Rho GTPase Rnd2 is crucial for survival, positioning, somatodendritic morphogenesis, and functional maturation of adult-born dentate granule neurons. Interestingly, most of these functions are specific to granule neurons generated during adulthood since the deletion of Rnd2 in neonatally-born granule neurons only affects dendritogenesis. In addition, suppression of Rnd2 in adult-born dentate granule neurons increases anxiety-like behavior whereas its deletion in pups has no such effect, a finding supporting the adult neurogenesis hypothesis of anxiety disorders. Thus, our results are in line with the view that adult neurogenesis is not a simple continuation of earlier processes from development, and establish a causal relationship between Rnd2 expression and anxiety.
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Affiliation(s)
- Thomas Kerloch
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Fanny Farrugia
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Lou Bouit
- grid.462202.00000 0004 0382 7329Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000 Bordeaux, France
| | - Marlène Maître
- grid.412041.20000 0001 2106 639XLaser microdissection Facility, Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Geoffrey Terral
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Muriel Koehl
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Pierre Mortessagne
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Julian Ik-Tsen Heng
- grid.1032.00000 0004 0375 4078Curtin Health Innovation Research Institute, Curtin University, 6102 Bentley, WA Australia
| | - Mylène Blanchard
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Hélène Doat
- grid.412041.20000 0001 2106 639XLaser microdissection Facility, Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France ,grid.412041.20000 0001 2106 639XTranscriptome Facility, Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Thierry Leste-Lasserre
- grid.412041.20000 0001 2106 639XTranscriptome Facility, Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Adeline Goron
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Delphine Gonzales
- grid.412041.20000 0001 2106 639XGenotyping Facility, Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - David Perrais
- grid.462202.00000 0004 0382 7329Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000 Bordeaux, France
| | - François Guillemot
- grid.451388.30000 0004 1795 1830The Francis Crick Institute, 1 Midland Road, London, NW1 1AT UK
| | - Djoher Nora Abrous
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Emilie Pacary
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300, Bordeaux, France.
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Masachs N, Charrier V, Farrugia F, Lemaire V, Blin N, Mazier W, Tronel S, Montaron MF, Ge S, Marsicano G, Cota D, Deroche-Gamonet V, Herry C, Abrous DN. The temporal origin of dentate granule neurons dictates their role in spatial memory. Mol Psychiatry 2021; 26:7130-7140. [PMID: 34526669 PMCID: PMC8873024 DOI: 10.1038/s41380-021-01276-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 07/20/2021] [Indexed: 11/27/2022]
Abstract
The dentate gyrus is one of the only brain regions that continues its development after birth in rodents. Adolescence is a very sensitive period during which cognitive competences are programmed. We investigated the role of dentate granule neurons (DGNs) born during adolescence in spatial memory and compared them with those generated earlier in life (in embryos or neonates) or during adulthood by combining functional imaging, retroviral and optogenetic tools to tag and silence DGNs. By imaging DGNs expressing Zif268, a proxy for neuronal activity, we found that neurons generated in adolescent rats (and not embryos or neonates) are transiently involved in spatial memory processing. In contrast, adult-generated DGNs are recruited at a later time point when animals are older. A causal relationship between the temporal origin of DGNs and spatial memory was confirmed by silencing DGNs in behaving animals. Our results demonstrate that the emergence of spatial memory depends on neurons born during adolescence, a function later assumed by neurons generated during adulthood.
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Affiliation(s)
- Nuria Masachs
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Vanessa Charrier
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Fanny Farrugia
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Valerie Lemaire
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Nicolas Blin
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Wilfrid Mazier
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Energy Balance and Obesity Group, U1215, F-33000 Bordeaux, France
| | - Sophie Tronel
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Marie-Françoise Montaron
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000 Bordeaux, France
| | - Shaoyu Ge
- grid.36425.360000 0001 2216 9681Program in Neuroscience, SUNY at Stony Brook, Stony Brook, New York, NY USA
| | - Giovanni Marsicano
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Endocannabinoids and Neuroadaptation Group, U1215, F-33000 Bordeaux, France
| | - Daniela Cota
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Energy Balance and Obesity Group, U1215, F-33000 Bordeaux, France
| | - Véronique Deroche-Gamonet
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Psychobiology of Drug Addiction Group, U1215, F-33000 Bordeaux, France
| | - Cyril Herry
- grid.412041.20000 0001 2106 639XUniv. Bordeaux, INSERM, Neurocenter Magendie, Neuronal Circuits of Associative Learning Group, U1215, F-33000 Bordeaux, France
| | - Djoher Nora Abrous
- Univ. Bordeaux, INSERM, Neurocenter Magendie, Neurogenesis and Pathophysiology Group, U1215, F-33000, Bordeaux, France.
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8
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Montaron M, Charrier V, Blin N, Garcia P, Abrous DN. Responsiveness of dentate neurons generated throughout adult life is associated with resilience to cognitive aging. Aging Cell 2020; 19:e13161. [PMID: 32599664 PMCID: PMC7431828 DOI: 10.1111/acel.13161] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/09/2020] [Accepted: 04/21/2020] [Indexed: 01/10/2023] Open
Abstract
During aging, some individuals are resilient to the decline of cognitive functions whereas others are vulnerable. These inter-individual differences in memory abilities have been associated with differences in the rate of hippocampal neurogenesis measured in elderlies. Whether the maintenance of the functionality of neurons generated throughout adult life is linked to resilience to cognitive aging remains completely unexplored. Using the immediate early gene Zif268, we analyzed the activation of dentate granule neurons born in adult (3-month-old), middle-aged (12-month-old), or senescent (18-month-old) rats (n = 96) in response to learning when animals reached 21 months of age. The activation of neurons born during the developmental period was also examined. We show that adult-born neurons can survive up to 19 months and that neurons generated 4, 10, or 19 months before learning, but not developmentally born neurons, are activated in senescent rats with good learning abilities. In contrast, aged rats with bad learning abilities do not exhibit activity-dependent regulation of newborn cells, whatever their birthdate. In conclusion, we propose that resilience to cognitive aging is associated with responsiveness of neurons born during adult life. These data add to our current knowledge by showing that the aging of memory abilities stems not only from the number but also from the responsiveness of adult-born neurons.
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Affiliation(s)
- Marie‐Françoise Montaron
- INSERM UMR 1215, Magendie Neurocenter Neurogenesis and Pathophysiology Group Bordeaux France
- Université de Bordeaux Bordeaux France
| | - Vanessa Charrier
- INSERM UMR 1215, Magendie Neurocenter Neurogenesis and Pathophysiology Group Bordeaux France
- Université de Bordeaux Bordeaux France
| | - Nicolas Blin
- INSERM UMR 1215, Magendie Neurocenter Neurogenesis and Pathophysiology Group Bordeaux France
- Université de Bordeaux Bordeaux France
| | - Pierre Garcia
- INSERM UMR 1215, Magendie Neurocenter Neurogenesis and Pathophysiology Group Bordeaux France
- Université de Bordeaux Bordeaux France
| | - Djoher Nora Abrous
- INSERM UMR 1215, Magendie Neurocenter Neurogenesis and Pathophysiology Group Bordeaux France
- Université de Bordeaux Bordeaux France
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9
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Kerloch T, Clavreul S, Goron A, Abrous DN, Pacary E. Dentate Granule Neurons Generated During Perinatal Life Display Distinct Morphological Features Compared With Later-Born Neurons in the Mouse Hippocampus. Cereb Cortex 2020; 29:3527-3539. [PMID: 30215686 DOI: 10.1093/cercor/bhy224] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 08/06/2018] [Indexed: 02/07/2023] Open
Abstract
In nonhuman mammals and in particular in rodents, most granule neurons of the dentate gyrus (DG) are generated during development and yet little is known about their properties compared with adult-born neurons. Although it is generally admitted that these populations are morphologically indistinguishable once mature, a detailed analysis of developmentally born neurons is lacking. Here, we used in vivo electroporation to label dentate granule cells (DGCs) generated in mouse embryos (E14.5) or in neonates (P0) and followed their morphological development up to 6 months after birth. By comparison with mature retrovirus-labeled DGCs born at weaning (P21) or young adult (P84) stages, we provide the evidence that perinatally born neurons, especially embryonically born cells, are morphologically distinct from later-born neurons and are thus easily distinguishable. In addition, our data indicate that semilunar and hilar GCs, 2 populations in ectopic location, are generated during the embryonic and the neonatal periods, respectively. Thus, our findings provide new insights into the development of the different populations of GCs in the DG and open new questions regarding their function in the brain.
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Affiliation(s)
- Thomas Kerloch
- INSERM U1215, Neurocentre Magendie, Bordeaux, France.,Université de Bordeaux, Bordeaux, France
| | - Solène Clavreul
- INSERM U1215, Neurocentre Magendie, Bordeaux, France.,Université de Bordeaux, Bordeaux, France
| | - Adeline Goron
- INSERM U1215, Neurocentre Magendie, Bordeaux, France.,Université de Bordeaux, Bordeaux, France
| | - Djoher Nora Abrous
- INSERM U1215, Neurocentre Magendie, Bordeaux, France.,Université de Bordeaux, Bordeaux, France
| | - Emilie Pacary
- INSERM U1215, Neurocentre Magendie, Bordeaux, France.,Université de Bordeaux, Bordeaux, France
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10
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von Wittgenstein J, Zheng F, Wittmann MT, Balta EA, Ferrazzi F, Schäffner I, Häberle BM, Valero-Aracama MJ, Koehl M, Miranda CJ, Kaspar BK, Ekici AB, Reis A, Abrous DN, Alzheimer C, Lie DC. Sox11 is an Activity-Regulated Gene with Dentate-Gyrus-Specific Expression Upon General Neural Activation. Cereb Cortex 2020; 30:3731-3743. [PMID: 32080705 DOI: 10.1093/cercor/bhz338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 06/25/2019] [Accepted: 07/04/2019] [Indexed: 01/21/2023] Open
Abstract
Neuronal activity initiates transcriptional programs that shape long-term changes in plasticity. Although neuron subtypes differ in their plasticity response, most activity-dependent transcription factors (TFs) are broadly expressed across neuron subtypes and brain regions. Thus, how region- and neuronal subtype-specific plasticity are established on the transcriptional level remains poorly understood. We report that in young adult (i.e., 6-8 weeks old) mice, the developmental TF SOX11 is induced in neurons within 6 h either by electroconvulsive stimulation or by exploration of a novel environment. Strikingly, SOX11 induction was restricted to the dentate gyrus (DG) of the hippocampus. In the novel environment paradigm, SOX11 was observed in a subset of c-FOS expressing neurons (ca. 15%); whereas around 75% of SOX11+ DG granule neurons were c-FOS+, indicating that SOX11 was induced in an activity-dependent fashion in a subset of neurons. Environmental enrichment or virus-mediated overexpression of SOX11 enhanced the excitability of DG granule cells and downregulated the expression of different potassium channel subunits, whereas conditional Sox11/4 knock-out mice presented the opposite phenotype. We propose that Sox11 is regulated in an activity-dependent fashion, which is specific to the DG, and speculate that activity-dependent Sox11 expression may participate in the modulation of DG neuron plasticity.
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Affiliation(s)
- Julia von Wittgenstein
- Institute of Biochemistry, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.,Department of Biology, Animal Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Fang Zheng
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Marie-Theres Wittmann
- Institute of Biochemistry, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.,Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Elli-Anna Balta
- Institute of Biochemistry, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Fulvia Ferrazzi
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Iris Schäffner
- Institute of Biochemistry, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Benjamin M Häberle
- Institute of Biochemistry, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Maria J Valero-Aracama
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Muriel Koehl
- Neurocentre Magendie U1215, INSERM and Université de Bordeaux, Bordeaux 33000, France
| | - Carlos J Miranda
- The Research Institute, Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Brian K Kaspar
- The Research Institute, Nationwide Children's Hospital, Columbus, OH 43205, USA
| | - Arif B Ekici
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - André Reis
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Djoher Nora Abrous
- Neurocentre Magendie U1215, INSERM and Université de Bordeaux, Bordeaux 33000, France
| | - Christian Alzheimer
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - D Chichung Lie
- Institute of Biochemistry, Emil Fischer Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
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11
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Clément T, Lee JB, Ichkova A, Rodriguez-Grande B, Fournier ML, Aussudre J, Ogier M, Haddad E, Canini F, Koehl M, Abrous DN, Obenaus A, Badaut J. Juvenile mild traumatic brain injury elicits distinct spatiotemporal astrocyte responses. Glia 2019; 68:528-542. [PMID: 31670865 DOI: 10.1002/glia.23736] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 09/30/2019] [Accepted: 10/01/2019] [Indexed: 12/14/2022]
Abstract
Mild-traumatic brain injury (mTBI) represents ~80% of all emergency room visits and increases the probability of developing long-term cognitive disorders in children. To date, molecular and cellular mechanisms underlying post-mTBI cognitive dysfunction are unknown. Astrogliosis has been shown to significantly alter astrocytes' properties following brain injury, potentially leading to significant brain dysfunction. However, such alterations have never been investigated in the context of juvenile mTBI (jmTBI). A closed-head injury model was used to study jmTBI on postnatal-day 17 mice. Astrogliosis was evaluated using glial fibrillary acidic protein (GFAP), vimentin, and nestin immunolabeling in somatosensory cortex (SSC), dentate gyrus (DG), amygdala (AMY), and infralimbic area (ILA) of prefrontal cortex in both hemispheres from 1 to 30 days postinjury (dpi). In vivo T2-weighted-imaging (T2WI) and diffusion tensor imaging (DTI) were performed at 7 and 30 dpi to examine tissue level structural alterations. Increased GFAP-labeling was observed up to 30 dpi in the ipsilateral SSC, the initial site of the impact. However, vimentin and nestin expression was not perturbed by jmTBI. The morphology of GFAP positive cells was significantly altered in the SSC, DG, AMY, and ILA up to 7 dpi that some correlated with magnetic resonance imaging changes. T2WI and DTI values were significantly altered at 30 dpi within these brain regions most prominently in regions distant from the impact site. Our data show that jmTBI triggers changes in astrocytic phenotype with a distinct spatiotemporal pattern. We speculate that the presence and time course of astrogliosis may contribute to pathophysiological processes and long-term structural alterations following jmTBI.
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Affiliation(s)
| | - Jeong B Lee
- Department of Physiology, Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | | | | | | | | | - Michael Ogier
- Département des Neurosciences et Sciences Cognitives, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Elizabeth Haddad
- Department of Pediatrics, University of California, Irvine, Irvine, California
| | - Frederic Canini
- Département des Neurosciences et Sciences Cognitives, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Muriel Koehl
- Neurocentre Magendie INSERM U1215, Bordeaux, France
| | | | - Andre Obenaus
- Department of Physiology, Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California.,Department of Pediatrics, University of California, Irvine, Irvine, California
| | - Jerome Badaut
- CNRS UMR5287, University of Bordeaux, Bordeaux, France.,Department of Physiology, Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
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12
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Donega V, Marcy G, Lo Giudice Q, Zweifel S, Angonin D, Fiorelli R, Abrous DN, Rival-Gervier S, Koehl M, Jabaudon D, Raineteau O. Transcriptional Dysregulation in Postnatal Glutamatergic Progenitors Contributes to Closure of the Cortical Neurogenic Period. Cell Rep 2019. [PMID: 29514086 DOI: 10.1016/j.celrep.2018.02.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Progenitors of cortical glutamatergic neurons (Glu progenitors) are usually thought to switch fate before birth to produce astrocytes. We used fate-mapping approaches to show that a large fraction of Glu progenitors persist in the postnatal forebrain after closure of the cortical neurogenesis period. Postnatal Glu progenitors do not accumulate during embryonal development but are produced by embryonal radial glial cells that persist after birth in the dorsal subventricular zone and continue to give rise to cortical neurons, although with low efficiency. Single-cell RNA sequencing reveals a dysregulation of transcriptional programs, which parallels changes in m6A methylation and correlates with the gradual decline in cortical neurogenesis observed in vivo. Rescuing experiments show that postnatal progenitors are partially permissive to genetic and pharmacological manipulations. Our study provides an in-depth characterization of postnatal Glu progenitors and identifies potential therapeutic targets for promoting brain repair.
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Affiliation(s)
- Vanessa Donega
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, 69500 Bron, France.
| | - Guillaume Marcy
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, 69500 Bron, France; Neurogenetics Department, Ecole Pratique des Hautes Etudes, PSL Research University, 75014 Paris, France
| | - Quentin Lo Giudice
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, 69500 Bron, France
| | - Stefan Zweifel
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, 69500 Bron, France
| | - Diane Angonin
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, 69500 Bron, France
| | - Roberto Fiorelli
- Brain Research Institute, University of Zürich/ETHZ, Zürich, Switzerland
| | - Djoher Nora Abrous
- Neurocentre Magendie, Neurogenesis and Physiopathology Group, Inserm, U1215, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Sylvie Rival-Gervier
- Stem Cell and Brain Research Institute U1208, Université Claude Bernard Lyon 1, Inserm, INRA, USC1361, 69500 Bron, France
| | - Muriel Koehl
- Neurocentre Magendie, Neurogenesis and Physiopathology Group, Inserm, U1215, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Denis Jabaudon
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
| | - Olivier Raineteau
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, 69500 Bron, France; Brain Research Institute, University of Zürich/ETHZ, Zürich, Switzerland.
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13
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André C, Catania C, Remus-Borel J, Ladeveze E, Leste-Lasserre T, Mazier W, Binder E, Gonzales D, Clark S, Guzman-Quevedo O, Abrous DN, Layé S, Cota D. mTORC1 pathway disruption abrogates the effects of the ciliary neurotrophic factor on energy balance and hypothalamic neuroinflammation. Brain Behav Immun 2018; 70:325-334. [PMID: 29548998 DOI: 10.1016/j.bbi.2018.03.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 03/02/2018] [Accepted: 03/12/2018] [Indexed: 11/19/2022] Open
Abstract
Ciliary neurotrophic factor (CNTF) potently decreases food intake and body weight in diet-induced obese mice by acting through neuronal circuits and pathways located in the arcuate nucleus (ARC) of the hypothalamus. CNTF also exerts pro-inflammatory actions within the brain. Here we tested whether CNTF modifies energy balance by inducing inflammatory responses in the ARC and whether these effects depend upon the mechanistic target of rapamycin complex 1 (mTORC1) pathway, which regulates both energy metabolism and inflammation. To this purpose, chow- and high fat diet (HFD)- fed mice lacking the S6 kinase 1 (S6K1-/-), a downstream target of mTORC1, and their wild-type (WT) littermates received 12 days continuous intracerebroventricular (icv) infusion of the CNTF analogue axokine (CNTFAx15). Behavioral, metabolic and molecular effects were evaluated. Central chronic administration of CNTFAx15 decreased body weight and feed efficiency in WT mice only, when fed HFD, but not chow. These metabolic effects correlated with increased number of iba-1 positive microglia specifically in the ARC and were accompanied by significant increases of IL-1β and TNF-α mRNA expression in the hypothalamus. Hypothalamic iNOS and SOCS3 mRNA, molecular markers of pro-inflammatory response, were also increased by CNTFAx15. All these changes were absent in S6K1-/- mice. This study reveals that CNTFAx15 requires a functional S6K1 to modulate energy balance and hypothalamic inflammation in a diet-dependent fashion. Further investigations should determine whether S6K1 is a suitable target for the treatment of pathologies characterized by a high neuroinflammatory state.
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Affiliation(s)
- Caroline André
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Caterina Catania
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Julie Remus-Borel
- INRA, Nutrition et Neurobiologie Intégrée, UMR 1286, F-33076 Bordeaux, France; University of Bordeaux, Nutrition et Neurobiologie Intégrée, UMR 1286, F-33076 Bordeaux, France
| | - Elodie Ladeveze
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Thierry Leste-Lasserre
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Wilfrid Mazier
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Elke Binder
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Delphine Gonzales
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Samantha Clark
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Omar Guzman-Quevedo
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Djoher Nora Abrous
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France
| | - Sophie Layé
- INRA, Nutrition et Neurobiologie Intégrée, UMR 1286, F-33076 Bordeaux, France; University of Bordeaux, Nutrition et Neurobiologie Intégrée, UMR 1286, F-33076 Bordeaux, France
| | - Daniela Cota
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France; University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, F-33000 Bordeaux, France.
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14
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Kanzari A, Bourcier-Lucas C, Freyssin A, Abrous DN, Haddjeri N, Lucas G. Inducing a long-term potentiation in the dentate gyrus is sufficient to produce rapid antidepressant-like effects. Mol Psychiatry 2018; 23:587-596. [PMID: 28485406 DOI: 10.1038/mp.2017.94] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 03/10/2017] [Accepted: 03/16/2017] [Indexed: 12/19/2022]
Abstract
Recent hypotheses propose that one prerequisite to obtain a rapid antidepressant (AD) effect would reside in processes of synaptic reinforcement occurring within the dentate gyrus (DG) of the hippocampus independently from neurogenesis. However, to date no relationship has been established between an increased DG synaptic plasticity, and rapid AD-like action. To the best of our knowledge, this study shows for the first time that inducing a long-term potentiation (LTP) within the DG by stimulating the perforant pathway (PP) is sufficient to induce such effects. Thus, Sprague-Dawley rats having undergone a successful LTP displayed a significant reduction of immobility when passed acutely 3 days thereafter in the forced swimming test (FST). Further, in a longitudinal paradigm using the pseudo-depressed Wistar-Kyoto rat strain, LTP elicited a decrease of FST immobility after only 2 days, whereas the AD desipramine was not effective before 16 days. In both models, the influence of LTP was transient, as it was no more observed after 8-9 days. No effects were observed on the locomotor activity or on anxiety-related behavior. Theta-burst stimulation of a brain region anatomically adjacent to the PP remained ineffective in the FST. Immunoreactivity of DG cells for phosphorylated histone H3 and doublecortin were not modified three days after LTP, indicating a lack of effect on both cell proliferation and neurogenesis. Finally, depleting brain serotonin contents reduced the success rate of LTP but did not affect its subsequent AD-like effects. These results confirm the 'plastic DG' theory of rapid AD efficacy. Beyond, they point out stimulations of the entorhinal cortex, from which the PP originates, as putative new approaches in AD research.
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Affiliation(s)
- A Kanzari
- INSERM and Université Claude Bernard Lyon 1, Institut Cellule Souche et Cerveau U846, Lyon, France.,Department of Biology, Université de Tunis El Manar, Tunis, Tunisia
| | - C Bourcier-Lucas
- INSERM and Université de Bordeaux, Neurocentre Magendie U1215, Bordeaux, France
| | - A Freyssin
- INSERM and Université Claude Bernard Lyon 1, Institut Cellule Souche et Cerveau U846, Lyon, France
| | - D N Abrous
- INSERM and Université de Bordeaux, Neurocentre Magendie U1215, Bordeaux, France
| | - N Haddjeri
- INSERM and Université Claude Bernard Lyon 1, Institut Cellule Souche et Cerveau U846, Lyon, France
| | - G Lucas
- INSERM and Université Claude Bernard Lyon 1, Institut Cellule Souche et Cerveau U846, Lyon, France.,INSERM and Université de Bordeaux, Neurocentre Magendie U1215, Bordeaux, France
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15
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Barker RA, Fricker RA, Abrous DN, Fawcett J, Dunnett SB. A Comparative Study of Preparation Techniques for Improving the Viability of Nigral Grafts using Vital Stains, in Vitro Cultures, and in Vivo Grafts. Cell Transplant 2017; 4:173-200. [PMID: 7539699 DOI: 10.1177/096368979500400204] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The intracerebral transplantation of embryonic dopaminergic nigral neurons, although relatively successful, leads to a fairly low yield of surviving cells. Many factors may influence the viability of dopaminergic grafts and one of these is the preparation of the tissue prior to transplantation. We have investigated the effects of different steps during the preparation and storage of embryonic rat nigral cell suspensions on their subsequent survival at a variety of different time points using a combination of techniques and studies. For studies concerned with the first 24 h we employed vital stains, in the period covering the next 7 days we used in vitro cultures, and in the long term experiment we used in vivo grafts. The results suggest that nigral cell suspensions may remain sufficiently viable for grafting for much longer periods than previously reported. In addition a number of parameters which affect cell survival have been characterised, including the age of the embryonic donor tissue, the use of proteolytic enzymes and the trituration procedure used during the preparation of the suspension. The optimal preparation technique, therefore, uses E13-E14 embryos with the dissected ventral mesencephalon being incubated in purified 0.1% trypsin solutions for 60 min and triturated using a flame polished Pasteur pipette. This may have important implications in improving intracerebral transplantation for Parkinson's disease.
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Affiliation(s)
- R A Barker
- MRC Cambridge Centre for Brain Repair, University of Cambridge, UK
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16
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André C, Guzman-Quevedo O, Rey C, Rémus-Borel J, Clark S, Castellanos-Jankiewicz A, Ladeveze E, Leste-Lasserre T, Nadjar A, Abrous DN, Laye S, Cota D. Inhibiting Microglia Expansion Prevents Diet-Induced Hypothalamic and Peripheral Inflammation. Diabetes 2017; 66:908-919. [PMID: 27903745 DOI: 10.2337/db16-0586] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 11/24/2016] [Indexed: 11/13/2022]
Abstract
Cell proliferation and neuroinflammation in the adult hypothalamus may contribute to the pathogenesis of obesity. We tested whether the intertwining of these two processes plays a role in the metabolic changes caused by 3 weeks of a high-saturated fat diet (HFD) consumption. Compared with chow-fed mice, HFD-fed mice had a rapid increase in body weight and fat mass and specifically showed an increased number of microglia in the arcuate nucleus (ARC) of the hypothalamus. Microglia expansion required the adequate presence of fats and carbohydrates in the diet because feeding mice a very high-fat, very low-carbohydrate diet did not affect cell proliferation. Blocking HFD-induced cell proliferation by central delivery of the antimitotic drug arabinofuranosyl cytidine (AraC) blunted food intake, body weight gain, and adiposity. AraC treatment completely prevented the increase in number of activated microglia in the ARC, the expression of the proinflammatory cytokine tumor necrosis factor-α in microglia, and the recruitment of the nuclear factor-κB pathway while restoring hypothalamic leptin sensitivity. Central blockade of cell proliferation also normalized circulating levels of the cytokines leptin and interleukin 1β and decreased peritoneal proinflammatory CD86 immunoreactive macrophage number. These findings suggest that inhibition of diet-dependent microglia expansion hinders body weight gain while preventing central and peripheral inflammatory responses due to caloric overload.
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Affiliation(s)
- Caroline André
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
- University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
| | - Omar Guzman-Quevedo
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
- University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
- Facultad de Químico-Farmacobiología, Universidad Michoacána de San Nicolás de Hidalgo, Morelia, Michoacán, Mexico
| | - Charlotte Rey
- INRA, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux, France
- University of Bordeaux, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux, France
| | - Julie Rémus-Borel
- INRA, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux, France
- University of Bordeaux, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux, France
| | - Samantha Clark
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
- University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
| | - Ashley Castellanos-Jankiewicz
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
- University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
| | - Elodie Ladeveze
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
- University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
| | - Thierry Leste-Lasserre
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
- University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
| | - Agnes Nadjar
- INRA, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux, France
- University of Bordeaux, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux, France
| | - Djoher Nora Abrous
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
- University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
| | - Sophie Laye
- INRA, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux, France
- University of Bordeaux, Nutrition et Neurobiologie Intégrée, UMR 1286, Bordeaux, France
| | - Daniela Cota
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
- University of Bordeaux, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U1215, Bordeaux, France
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17
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Abstract
During the last decade, the questions on the functionality of adult neurogenesis have changed their emphasis from if to how the adult-born neurons participate in a variety of memory processes. The emerging answers are complex because we are overwhelmed by a variety of behavioral tasks that apparently require new neurons to be performed optimally. With few exceptions, the hippocampal memory system seems to use the newly generated neurons for multiple roles. Adult neurogenesis has given the dentate gyrus new capabilities not previously thought possible within the scope of traditional synaptic plasticity. Looking at these new developments from the perspective of past discoveries, the science of adult neurogenesis has emerged from its initial phase of being, first, a surprising oddity and, later, exciting possibility, to the present state of being an integral part of mainstream neuroscience. The answers to many remaining questions regarding adult neurogenesis will come along only with our growing understanding of the functionality of the brain as a whole. This, in turn, will require integration of multiple levels of organization from molecules and cells to circuits and systems, ultimately resulting in comprehension of behavioral outcomes.
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Affiliation(s)
- Djoher Nora Abrous
- Inserm U862, Bordeaux-F33077, France Université de Bordeaux, Bordeaux-F33077, France
| | - Jan Martin Wojtowicz
- Department of Physiology, University of Toronto, Medical Sciences Building, Toronto, Ontario M5S 1A8, Canada
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18
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Cathala A, Devroye C, Maitre M, Piazza PV, Abrous DN, Revest JM, Spampinato U. Serotonin2C receptors modulate dopamine transmission in the nucleus accumbens independently of dopamine release: behavioral, neurochemical and molecular studies with cocaine. Addict Biol 2015; 20:445-57. [PMID: 24661380 DOI: 10.1111/adb.12137] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In keeping with its ability to control the mesoaccumbens dopamine (DA) pathway, the serotonin2C receptor (5-HT2C R) plays a key role in mediating the behavioral and neurochemical effects of drugs of abuse. Studies assessing the influence of 5-HT2C R agonists on cocaine-induced responses have suggested that 5-HT2C Rs can modulate mesoaccumbens DA pathway activity independently of accumbal DA release, thereby controlling DA transmission in the nucleus accumbens (NAc). In the present study, we assessed this hypothesis by studying the influence of the 5-HT2C R agonist Ro 60-0175 on cocaine-induced behavioral, neurochemical and molecular responses. The i.p. administration of 1 mg/kg Ro 60-0175 inhibited hyperlocomotion induced by cocaine (15 mg/kg, i.p.), had no effect on cocaine-induced DA outflow in the shell, and increased it in the core subregion of the NAc. Furthermore, Ro 60-0175 inhibited the late-onset locomotion induced by the subcutaneous administration of the DA-D2 R agonist quinpirole (0.5 mg/kg), as well as cocaine-induced increase in c-Fos immunoreactivity in NAc subregions. Finally, Ro 60-0175 inhibited cocaine-induced phosphorylation of the DA and c-AMP regulated phosphoprotein of Mr 32 kDa (DARPP-32) at threonine residues in the NAc core, this effect being reversed by the selective 5-HT2C R antagonist SB 242084 (0.5 mg/kg, i.p.). Altogether, these findings demonstrate that 5-HT2C Rs are capable of modulating mesoaccumbens DA pathway activity at post-synaptic level by specifically controlling DA signaling in the NAc core subregion. In keeping with the tight relationship between locomotor activity and NAc DA function, this interaction could participate in the inhibitory control of cocaine-induced locomotor activity.
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Affiliation(s)
- Adeline Cathala
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Université de Bordeaux; France
| | - Céline Devroye
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Université de Bordeaux; France
| | - Marlène Maitre
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Université de Bordeaux; France
| | - Pier Vincenzo Piazza
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Université de Bordeaux; France
| | - Djoher Nora Abrous
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Neurocentre Magendie, Neurogenesis and Pathophysiology Group; Inserm U862; France
| | - Jean-Michel Revest
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Université de Bordeaux; France
| | - Umberto Spampinato
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Université de Bordeaux; France
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Devroye C, Cathala A, Maitre M, Piazza PV, Abrous DN, Revest JM, Spampinato U. Serotonin2C receptor stimulation inhibits cocaine-induced Fos expression and DARPP-32 phosphorylation in the rat striatum independently of dopamine outflow. Neuropharmacology 2015; 89:375-81. [DOI: 10.1016/j.neuropharm.2014.10.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 10/16/2014] [Accepted: 10/17/2014] [Indexed: 11/16/2022]
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Tronel S, Lemaire V, Charrier V, Montaron MF, Abrous DN. Influence of ontogenetic age on the role of dentate granule neurons. Brain Struct Funct 2014; 220:645-61. [PMID: 24510284 DOI: 10.1007/s00429-014-0715-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 01/24/2014] [Indexed: 12/20/2022]
Abstract
New neurons are continuously produced in the adult dentate gyrus of the hippocampus, a key structure in learning and memory. It has been shown that adult neurogenesis is crucial for normal memory processing. However, it is not known whether neurons born during the developmental period and during adulthood support the same functions. Here, we demonstrate that neurons born in neonates (first postnatal week) are activated in different memory processes when they are mature compared to neurons born in adults. By imaging the activation of these two different neuron generations in the same rat and using the IEG Zif268 and Fos, we show that these neurons are involved in discriminating dissimilar contexts and spatial problem solving, respectively. These findings demonstrate that the ontogenetic stage during which neurons are generated is crucial for their function within the memory network.
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Affiliation(s)
- P J Lucassen
- SILS-CNS, University of Amsterdam, Amsterdam, The Netherlands.
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Brayda-Bruno L, Mons N, Yee BK, Micheau J, Abrous DN, Nogues X, Marighetto A. Partial loss in septo-hippocampal cholinergic neurons alters memory-dependent measures of brain connectivity without overt memory deficits. Neurobiol Dis 2013; 54:372-81. [PMID: 23376311 DOI: 10.1016/j.nbd.2013.01.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 01/07/2013] [Accepted: 01/10/2013] [Indexed: 11/18/2022] Open
Abstract
The functional relevance of septo-hippocampal cholinergic (SHC) degeneration to the degradation of hippocampus-dependent declarative memory (DM) in aging and Alzheimer's disease (AD) remains ill-defined. Specifically, selective SHC lesions often fail to induce overt memory impairments in animal models. In spite of apparent normal performance, however, neuronal activity within relevant brain structures might be altered by SHC disruption. We hypothesized that partial SHC degeneration may contribute to functional alterations within memory circuits occurring in aging before DM decline. In young adult mice, we studied the effects of behaviorally ineffective (saporin-induced) SHC lesions - similar in extent to that seen in aged animals - on activity patterns and functional connectivity between three main neural memory systems: the septo-hippocampal system, the striatum and the amygdala that sustain declarative, procedural and emotional memory, respectively. Animals were trained in a radial maze procedure dissociating the human equivalents of relational/DM and non-R/DM expressions in animals. Test-induced Fos activation pattern revealed that the partial SHC lesion significantly altered the brain's functional activities and connectivity (co-activation pattern) despite the absence of overt behavioral deficit. Specifically, hippocampal CA3 hyperactivity and abnormal septo-hippocampo-amygdalar inter-connectivity resemble those observed in aging and prodromal AD. Hence, SHC neurons critically coordinate hippocampal function in concert with extra-hippocampal structures in accordance with specific mnemonic demand. Although partial SHC degeneration is not sufficient to impact DM performance by itself, the connectivity change might predispose the emergence of subsequent DM loss when, due to additional age-related insults, the brain can no longer compensate the holistic imbalance caused by cholinergic loss.
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Affiliation(s)
- Laurent Brayda-Bruno
- INSERM, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U862, F-33000 Bordeaux, France
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Koehl M, van der Veen R, Gonzales D, Piazza PV, Abrous DN. Interplay of maternal care and genetic influences in programming adult hippocampal neurogenesis. Biol Psychiatry 2012; 72:282-9. [PMID: 22483276 DOI: 10.1016/j.biopsych.2012.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 02/16/2012] [Accepted: 03/01/2012] [Indexed: 02/06/2023]
Abstract
BACKGROUND Adult hippocampal neurogenesis, which is involved in the physiopathology of hippocampal functions, is genetically determined and influenced by early life events. However, studies on the interaction of these determining forces are lacking. This prompted us to investigate whether adult hippocampal neurogenesis can be modulated by maternal care and whether this influence depends upon the genetic background of the individual. METHODS We used a model of fostering that allows singling out the influence of the genetic make-up of the pups on the outcome of maternal behavior. Mice from two different inbred strains (C57BL/6J and DBA/2J) known to differ in their baseline neurogenesis as well as in their sensitivity to the influence of environmental experiences were raised by nonrelated mothers from the AKR/Ola (AKR) and C3H/He (C3H) strains exhibiting low- and high-pup-oriented behavior, respectively. Neurogenesis was then assessed in the dentate gyrus of the adult adopted C57BL/6J and DBA/2J mice. RESULTS We show that both the number and the morphological features of newborn granule cells in the dentate gyrus are determined by the maternal environment to which mice were exposed as pups and that this sensitivity to maternal environment is observed only in genetically vulnerable subjects. CONCLUSIONS Altogether, our data indicate interplay between early environment and the genetic envelop of an individual in determining adult hippocampal neurogenesis. Our experimental approach could thus contribute to the identification of factors determining the neurogenic potential of the adult hippocampus.
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Affiliation(s)
- Muriel Koehl
- Institut National de la Santé et de la Recherche Médicale, Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, 146 rue Leo Saignat, Bordeaux, France.
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Pacary E, Haas MA, Wildner H, Azzarelli R, Bell DM, Abrous DN, Guillemot F. Visualization and genetic manipulation of dendrites and spines in the mouse cerebral cortex and hippocampus using in utero electroporation. J Vis Exp 2012:4163. [PMID: 22872172 PMCID: PMC3476406 DOI: 10.3791/4163] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In utero electroporation (IUE) has become a powerful technique to study the development of different regions of the embryonic nervous system (1-5). To date this tool has been widely used to study the regulation of cellular proliferation, differentiation and neuronal migration especially in the developing cerebral cortex (6-8). Here we detail our protocol to electroporate in utero the cerebral cortex and the hippocampus and provide evidence that this approach can be used to study dendrites and spines in these two cerebral regions. Visualization and manipulation of neurons in primary cultures have contributed to a better understanding of the processes involved in dendrite, spine and synapse development. However neurons growing in vitro are not exposed to all the physiological cues that can affect dendrite and/or spine formation and maintenance during normal development. Our knowledge of dendrite and spine structures in vivo in wild-type or mutant mice comes mostly from observations using the Golgi-Cox method( 9). However, Golgi staining is considered to be unpredictable. Indeed, groups of nerve cells and fiber tracts are labeled randomly, with particular areas often appearing completely stained while adjacent areas are devoid of staining. Recent studies have shown that IUE of fluorescent constructs represents an attractive alternative method to study dendrites, spines as well as synapses in mutant / wild-type mice (10-11) (Figure 1A). Moreover in comparison to the generation of mouse knockouts, IUE represents a rapid approach to perform gain and loss of function studies in specific population of cells during a specific time window. In addition, IUE has been successfully used with inducible gene expression or inducible RNAi approaches to refine the temporal control over the expression of a gene or shRNA (12). These advantages of IUE have thus opened new dimensions to study the effect of gene expression/suppression on dendrites and spines not only in specific cerebral structures (Figure 1B) but also at a specific time point of development (Figure 1C). Finally, IUE provides a useful tool to identify functional interactions between genes involved in dendrite, spine and/or synapse development. Indeed, in contrast to other gene transfer methods such as virus, it is straightforward to combine multiple RNAi or transgenes in the same population of cells. In summary, IUE is a powerful method that has already contributed to the characterization of molecular mechanisms underlying brain function and disease and it should also be useful in the study of dendrites and spines.
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Affiliation(s)
- Emilie Pacary
- Division of Molecular Neurobiology, MRC National Institute for Medical Research.
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Han J, Kesner P, Metna-Laurent M, Duan T, Xu L, Georges F, Koehl M, Abrous DN, Mendizabal-Zubiaga J, Grandes P, Liu Q, Bai G, Wang W, Xiong L, Ren W, Marsicano G, Zhang X. Acute cannabinoids impair working memory through astroglial CB1 receptor modulation of hippocampal LTD. Cell 2012; 148:1039-50. [PMID: 22385967 DOI: 10.1016/j.cell.2012.01.037] [Citation(s) in RCA: 337] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 10/21/2011] [Accepted: 01/11/2012] [Indexed: 01/27/2023]
Abstract
Impairment of working memory is one of the most important deleterious effects of marijuana intoxication in humans, but its underlying mechanisms are presently unknown. Here, we demonstrate that the impairment of spatial working memory (SWM) and in vivo long-term depression (LTD) of synaptic strength at hippocampal CA3-CA1 synapses, induced by an acute exposure of exogenous cannabinoids, is fully abolished in conditional mutant mice lacking type-1 cannabinoid receptors (CB(1)R) in brain astroglial cells but is conserved in mice lacking CB(1)R in glutamatergic or GABAergic neurons. Blockade of neuronal glutamate N-methyl-D-aspartate receptors (NMDAR) and of synaptic trafficking of glutamate α-amino-3-hydroxy-5-methyl-isoxazole propionic acid receptors (AMPAR) also abolishes cannabinoid effects on SWM and LTD induction and expression. We conclude that the impairment of working memory by marijuana and cannabinoids is due to the activation of astroglial CB(1)R and is associated with astroglia-dependent hippocampal LTD in vivo.
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Affiliation(s)
- Jing Han
- College of Life Sciences and Key Laboratory of Modern Teaching Technology, Shaanxi Normal University, Xian, China
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Noguès X, Corsini MM, Marighetto A, Abrous DN. Functions for adult neurogenesis in memory: an introduction to the neurocomputational approach and to its contribution. Behav Brain Res 2011; 227:418-25. [PMID: 21856335 DOI: 10.1016/j.bbr.2011.08.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 08/04/2011] [Accepted: 08/06/2011] [Indexed: 01/26/2023]
Abstract
Until recently, it was believed that the introduction of new neurons in neuronal networks was incompatible with memory function. Since the rediscovery of adult hippocampal neurogenesis, behavioral data demonstrate that adult neurogenesis is required for memory processing. We examine neurocomputational studies to identify which basic mechanisms involved in memory might be mediated by adult neurogenesis. Mainly, adult neurogenesis might be involved in the reduction of catastrophic interference and in a time-related pattern separation function. Artificial neuronal networks suggest that the selective recruitment of new-born or old neurons is not stochastic, but depends on environmental requirements. This leads us to propose the novel concept of "soft-supervision". Soft-supervision would be a biologically plausible process, by which the environment is able to influence activation and learning rules of neurons differentially.
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Affiliation(s)
- X Noguès
- INSERM U862, Neurocenter Magendie, Pathophysiology of Declarative Memory group, Bordeaux F33077, France.
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Massa F, Koehl M, Wiesner T, Grosjean N, Revest JM, Piazza PV, Abrous DN, Oliet SHR. Conditional reduction of adult neurogenesis impairs bidirectional hippocampal synaptic plasticity. Proc Natl Acad Sci U S A 2011; 108:6644-9. [PMID: 21464314 PMCID: PMC3081011 DOI: 10.1073/pnas.1016928108] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Adult neurogenesis is a process by which the brain produces new neurons once development has ceased. Adult hippocampal neurogenesis has been linked to the relational processing of spatial information, a role attributed to the contribution of newborn neurons to long-term potentiation (LTP). However, whether newborn neurons also influence long-term depression (LTD), and how synaptic transmission and plasticity are affected as they incorporate their network, remain to be determined. To address these issues, we took advantage of a genetic model in which a majority of adult-born neurons can be selectively ablated in the dentate gyrus (DG) and, most importantly, in which neurogenesis can be restored on demand. Using electrophysiological recordings, we show that selective reduction of adult-born neurons impairs synaptic transmission at medial perforant pathway synapses onto DG granule cells. Furthermore, LTP and LTD are largely compromised at these synapses, probably as a result of an increased induction threshold. Whereas the deficits in synaptic transmission and plasticity are completely rescued by restoring neurogenesis, these synapses regain their ability to express LTP much faster than their ability to express LTD. These results demonstrate that both LTP and LTD are influenced by adult neurogenesis. They also indicate that as newborn neurons integrate their network, the ability to express bidirectional synaptic plasticity is largely improved at these synapses. These findings establish that adult neurogenesis is an important process for synaptic transmission and bidirectional plasticity in the DG, accounting for its role in efficiently integrating novel incoming information and in forming new memories.
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Affiliation(s)
- Federico Massa
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Glia-Neuron Interactions Group, F33077 Bordeaux, France
- Université de Bordeaux, F33077 Bordeaux, France
| | - Muriel Koehl
- Université de Bordeaux, F33077 Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Neurogenesis and Pathophysiology Group, F33077 Bordeaux, France
| | - Theresa Wiesner
- Université de Bordeaux, F33077 Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Endocannabinoids and Neuroadaptation Group, F33077 Bordeaux, France; and
| | - Noelle Grosjean
- Université de Bordeaux, F33077 Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Neurogenesis and Pathophysiology Group, F33077 Bordeaux, France
| | - Jean-Michel Revest
- Université de Bordeaux, F33077 Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Pathophysiology of Addiction Group, F33077 Bordeaux, France
| | - Pier-Vincenzo Piazza
- Université de Bordeaux, F33077 Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Pathophysiology of Addiction Group, F33077 Bordeaux, France
| | - Djoher Nora Abrous
- Université de Bordeaux, F33077 Bordeaux, France
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Neurogenesis and Pathophysiology Group, F33077 Bordeaux, France
| | - Stéphane H. R. Oliet
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie, Glia-Neuron Interactions Group, F33077 Bordeaux, France
- Université de Bordeaux, F33077 Bordeaux, France
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Tronel S, Belnoue L, Grosjean N, Revest JM, Piazza PV, Koehl M, Abrous DN. Adult-born neurons are necessary for extended contextual discrimination. Hippocampus 2010; 22:292-8. [PMID: 21049483 DOI: 10.1002/hipo.20895] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2010] [Indexed: 12/25/2022]
Abstract
New neurons are continuously produced in the adult dentate gyrus of the hippocampus. It has been shown that one of the functions of adult neurogenesis is to support spatial pattern separation, a process that transforms similar memories into nonoverlapping representations. This prompted us to investigate whether adult-born neurons are required for discriminating two contexts, i.e., for identifying a familiar environment and detect any changes introduced in it. We show that depleting adult-born neurons impairs the animal's ability to disambiguate two contexts after extensive training. These data suggest that the continuous production of new dentate neurons plays a crucial role in extracting and separating efficiently contextual representation in order to discriminate features within events.
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Dupret D, Abrous DN. [A new chapter in the field of memory: hippocampal neo-neurogenesis]. Biol Aujourdhui 2010; 204:113-29. [PMID: 20950556 DOI: 10.1051/jbio/2010004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2010] [Indexed: 11/14/2022]
Abstract
The dogma according to which "once the development of the central nervous system ended, generation of neurons was impossible" has been challenged by the discovery that new neurons are created in specific regions of the adult mammalian brain. This discovery has been one of the most controversial of modern neuroscience. One of these regions is the dentate gyrus of the hippocampal formation, a key structure in memory. Here we will review our current knowledge on the role of adult hippocampal neurogenesis in memory and in the pathophysiology of memory. In particular we will review evidence showing that adult-born neurons are required for learning and memory and that an alteration of their production rate leads to memory impairments. We also discuss how neurogenesis is finely shaped by learning for the purpose of mnemonic information processing.
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Affiliation(s)
- David Dupret
- MRC Anatomical Neuropharmacology Unit, Oxford OX1 3TH, UK
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Lazarini F, Mouthon MA, Gheusi G, de Chaumont F, Olivo-Marin JC, Lamarque S, Abrous DN, Boussin FD, Lledo PM. Cellular and behavioral effects of cranial irradiation of the subventricular zone in adult mice. PLoS One 2009; 4:e7017. [PMID: 19753118 PMCID: PMC2737283 DOI: 10.1371/journal.pone.0007017] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Accepted: 07/13/2009] [Indexed: 11/25/2022] Open
Abstract
Background In mammals, new neurons are added to the olfactory bulb (OB) throughout life. Most of these new neurons, granule and periglomerular cells originate from the subventricular zone (SVZ) lining the lateral ventricles and migrate via the rostral migratory stream toward the OB. Thousands of new neurons appear each day, but the function of this ongoing neurogenesis remains unclear. Methodology/Principal Findings In this study, we irradiated adult mice to impair constitutive OB neurogenesis, and explored the functional impacts of this irradiation on the sense of smell. We found that focal irradiation of the SVZ greatly decreased the rate of production of new OB neurons, leaving other brain areas intact. This effect persisted for up to seven months after exposure to 15 Gray. Despite this robust impairment, the thresholds for detecting pure odorant molecules and short-term olfactory memory were not affected by irradiation. Similarly, the ability to distinguish between odorant molecules and the odorant-guided social behavior of irradiated mice were not affected by the decrease in the number of new neurons. Only long-term olfactory memory was found to be sensitive to SVZ irradiation. Conclusion/Significance These findings suggest that the continuous production of adult-generated neurons is involved in consolidating or restituting long-lasting olfactory traces.
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Affiliation(s)
- Françoise Lazarini
- Institut Pasteur, Laboratory for Perception and Memory, Paris, France
- Centre National de la Recherche Scientifique (CNRS) Unité de Recherche Associée (URA), Paris, France
| | - Marc-André Mouthon
- CEA, DSV, iRCM, SCSR, Laboratoire de RadioPathologie, INSERM U967, Fontenay-aux-Roses, France
| | - Gilles Gheusi
- Institut Pasteur, Laboratory for Perception and Memory, Paris, France
- Centre National de la Recherche Scientifique (CNRS) Unité de Recherche Associée (URA), Paris, France
| | - Fabrice de Chaumont
- Institut Pasteur, Unité Analyse d'Images Quantitative, CNRS (URA 2582), Paris, France
| | | | - Stéphanie Lamarque
- INSERM U862, Neurocentre Magendie, Neurogenesis and Pathophysiology group, Bordeaux, France
- Université de Bordeaux, Bordeaux, France
| | - Djoher Nora Abrous
- INSERM U862, Neurocentre Magendie, Neurogenesis and Pathophysiology group, Bordeaux, France
- Université de Bordeaux, Bordeaux, France
| | - François D. Boussin
- CEA, DSV, iRCM, SCSR, Laboratoire de RadioPathologie, INSERM U967, Fontenay-aux-Roses, France
| | - Pierre-Marie Lledo
- Institut Pasteur, Laboratory for Perception and Memory, Paris, France
- Centre National de la Recherche Scientifique (CNRS) Unité de Recherche Associée (URA), Paris, France
- * E-mail:
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Bonnet E, Touyarot K, Alfos S, Pallet V, Higueret P, Abrous DN. Retinoic acid restores adult hippocampal neurogenesis and reverses spatial memory deficit in vitamin A deprived rats. PLoS One 2008; 3:e3487. [PMID: 18941534 PMCID: PMC2567033 DOI: 10.1371/journal.pone.0003487] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Accepted: 09/25/2008] [Indexed: 01/23/2023] Open
Abstract
A dysfunction of retinoid hippocampal signaling pathway has been involved in the appearance of affective and cognitive disorders. However, the underlying neurobiological mechanisms remain unknown. Hippocampal granule neurons are generated throughout life and are involved in emotion and memory. Here, we investigated the effects of vitamin A deficiency (VAD) on neurogenesis and memory and the ability of retinoic acid (RA) treatment to prevent VAD-induced impairments. Adult retinoid-deficient rats were generated by a vitamin A-free diet from weaning in order to allow a normal development. The effects of VAD and/or RA administration were examined on hippocampal neurogenesis, retinoid target genes such as neurotrophin receptors and spatial reference memory measured in the water maze. Long-term VAD decreased neurogenesis and led to memory deficits. More importantly, these effects were reversed by 4 weeks of RA treatment. These beneficial effects may be in part related to an up-regulation of retinoid-mediated molecular events, such as the expression of the neurotrophin receptor TrkA. We have demonstrated for the first time that the effect of vitamin A deficient diet on the level of hippoccampal neurogenesis is reversible and that RA treatment is important for the maintenance of the hippocampal plasticity and function.
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Affiliation(s)
- Emilie Bonnet
- Nutrition & Neurosciences laboratory, University of Bordeaux 1, Talence, France
- University of Bordeaux 2, Bordeaux, France
| | - Katia Touyarot
- Nutrition & Neurosciences laboratory, University of Bordeaux 1, Talence, France
- University of Bordeaux 2, Bordeaux, France
| | - Serge Alfos
- Nutrition & Neurosciences laboratory, University of Bordeaux 1, Talence, France
- University of Bordeaux 2, Bordeaux, France
| | - Véronique Pallet
- Nutrition & Neurosciences laboratory, University of Bordeaux 1, Talence, France
- University of Bordeaux 2, Bordeaux, France
| | - Paul Higueret
- Nutrition & Neurosciences laboratory, University of Bordeaux 1, Talence, France
- University of Bordeaux 2, Bordeaux, France
| | - Djoher Nora Abrous
- University of Bordeaux 2, Bordeaux, France
- Neurogenesis & Pathophysiology laboratory, Bordeaux Neuroscience Research Center, INSERM 862, Bordeaux, France
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Abstract
Neuroplasticity is characterized by growth and branching of dendrites, remodeling of synaptic contacts, and neurogenesis, thus allowing the brain to adapt to changes over time. It is maintained in adulthood but strongly repressed during aging. An age-related decline in neurogenesis is particularly pronounced in the two adult neurogenic areas, the subventricular zone and the dentate gyrus. This age-related decline seems to be attributable mainly to limited proliferation, associated with an age-dependent increase in quiescence and/or a lengthening of the cell cycle, and is closely dependent on environmental changes. Indeed, when triggered by appropriate signals, neurogenesis can be reactivated in senescent brains, thus confirming the idea that the age-related decrease in new neuron production is not an irreversible, cell-intrinsic process. The coevolution of neurogenesis and age-related memory deficits--especially regarding spatial memory--during senescence supports the idea that new neurons in the adult brain participate in memory processing, and that a reduction in the ability to generate new neurons contributes to the appearance of memory deficits with advanced age. Furthermore, the age-related changes in hippocampal plasticity and function are under environmental influences that can favor successful or pathological aging. A better understanding of the mechanisms that regulate neurogenesis is necessary to develop new therapeutic tools to cure or prevent the development of memory disorders that may appear during the course of aging in some individuals.
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Affiliation(s)
- Elodie Drapeau
- Doetsch's Laboratory, Columbia University, Department of PathologyP&S 14-511, 630 W 168th Street, New York, NY 10032, USA
| | - Djoher Nora Abrous
- INSERM U862, Bordeaux Neuroscience Research Center, University of Bordeaux 2Bordeaux Cedex 33077, France
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Dupret D, Revest JM, Koehl M, Ichas F, De Giorgi F, Costet P, Abrous DN, Piazza PV. Spatial relational memory requires hippocampal adult neurogenesis. PLoS One 2008; 3:e1959. [PMID: 18509506 PMCID: PMC2396793 DOI: 10.1371/journal.pone.0001959] [Citation(s) in RCA: 446] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Accepted: 03/03/2008] [Indexed: 01/28/2023] Open
Abstract
The dentate gyrus of the hippocampus is one of the few regions of the mammalian brain where new neurons are generated throughout adulthood. This adult neurogenesis has been proposed as a novel mechanism that mediates spatial memory. However, data showing a causal relationship between neurogenesis and spatial memory are controversial. Here, we developed an inducible transgenic strategy allowing specific ablation of adult-born hippocampal neurons. This resulted in an impairment of spatial relational memory, which supports a capacity for flexible, inferential memory expression. In contrast, less complex forms of spatial knowledge were unaltered. These findings demonstrate that adult-born neurons are necessary for complex forms of hippocampus-mediated learning.
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Affiliation(s)
- David Dupret
- INSERM U862, Institut F. Magendie, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
| | - Jean-Michel Revest
- INSERM U862, Institut F. Magendie, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
| | - Muriel Koehl
- INSERM U862, Institut F. Magendie, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
| | - François Ichas
- INSERM E347, Institut Bergonié, University of Bordeaux 2, Bordeaux, France
| | | | - Pierre Costet
- Laboratoire de Transgénèse, University of Bordeaux 2, Bordeaux, France
| | - Djoher Nora Abrous
- INSERM U862, Institut F. Magendie, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
| | - Pier Vincenzo Piazza
- INSERM U862, Institut F. Magendie, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
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Dupret D, Fabre A, Döbrössy MD, Panatier A, Rodríguez JJ, Lamarque S, Lemaire V, Oliet SHR, Piazza PV, Abrous DN. Spatial learning depends on both the addition and removal of new hippocampal neurons. PLoS Biol 2008; 5:e214. [PMID: 17683201 PMCID: PMC1939885 DOI: 10.1371/journal.pbio.0050214] [Citation(s) in RCA: 289] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Accepted: 06/11/2007] [Indexed: 12/18/2022] Open
Abstract
The role of adult hippocampal neurogenesis in spatial learning remains a matter of debate. Here, we show that spatial learning modifies neurogenesis by inducing a cascade of events that resembles the selective stabilization process characterizing development. Learning promotes survival of relatively mature neurons, apoptosis of more immature cells, and finally, proliferation of neural precursors. These are three interrelated events mediating learning. Thus, blocking apoptosis impairs memory and inhibits learning-induced cell survival and cell proliferation. In conclusion, during learning, similar to the selective stabilization process, neuronal networks are sculpted by a tightly regulated selection and suppression of different populations of newly born neurons. The birth of adult hippocampal neurons is associated with enhanced learning and memory performance. In particular, spatial learning increases the survival and the proliferation of newborn cells, but surprisingly, it also decreases their number. Here, we hypothesized that spatial learning also depends upon the death of newborn hippocampal neurons. We examined the effect of spatial learning in the water maze on cell birth and death in the rodent hippocampus. We then determined the influence of an inhibitor of cell death on memory abilities and learning-induced changes in cell death, cell proliferation, and cell survival. We show that learning increases the elimination of the youngest newborn cells during a specific developmental period. The cell-death inhibitor impairs memory abilities and blocks the learning-induced cell death, the survival-promoting effect of learning on older newly born neurons, and the subsequent learning-induced proliferation of neural precursors. These results show that spatial learning induces cell death in the hippocampus, a phenomenon that subserves learning and is necessary for both the survival of older newly born neurons and the proliferation of neural precursors. These findings suggest that during learning, neuronal networks are sculpted by a tightly regulated selection of newly born neurons and reveal a novel mechanism mediating learning and memory in the adult brain. Spatial learning-induced cell death in the hippocampus is necessary for the survival of newly born cells, the proliferation of neural precursors, and the retention of spatial memories.
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Affiliation(s)
- David Dupret
- INSERM U862, Bordeaux Neuroscience Research Center, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
| | - Annabelle Fabre
- INSERM U862, Bordeaux Neuroscience Research Center, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
| | - Màtè Dàniel Döbrössy
- INSERM U862, Bordeaux Neuroscience Research Center, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
| | - Aude Panatier
- INSERM U862, Bordeaux Neuroscience Research Center, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
| | | | - Stéphanie Lamarque
- INSERM U862, Bordeaux Neuroscience Research Center, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
| | - Valerie Lemaire
- INSERM U862, Bordeaux Neuroscience Research Center, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
| | - Stephane H. R Oliet
- INSERM U862, Bordeaux Neuroscience Research Center, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
| | - Pier-Vincenzo Piazza
- INSERM U862, Bordeaux Neuroscience Research Center, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
| | - Djoher Nora Abrous
- INSERM U862, Bordeaux Neuroscience Research Center, Bordeaux, France
- University of Bordeaux 2, Bordeaux, France
- * To whom correspondence should be addressed. E-mail:
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Abstract
The importance of maternal care in shaping an individual's phenotype in health and disease is becoming more and more apparent in both human and animal studies. However, in mouse studies using inbred strains or knockout mice to analyze the genetic influences on the development of normal and aberrant behavioral phenotypes, maternal behavior is very poorly characterized and often ignored. This study provides an extensive analysis of spontaneous maternal behavior of inbred mice in three conditions: (1) comparing two commonly used strains, (2) analyzing the impact of adopting pups from the same strain (intrastrain cross-fostering) and (3) analyzing the impact of adopting pups from a different strain (interstrain cross-fostering). For each condition, maternal behavior was analyzed continuously over 23-h periods on postnatal days 2, 4, 6 and 9. We report that (1) the maternal behavior of C57BL/6J and DBA/2J dams toward their biological offspring is highly similar, (2) intrastrain cross-fostering has minimal impact on maternal behavior of C57BL/6J and DBA/2J dams, (3) interstrain cross-fostering does not modify the strain differences in maternal care observed between AKR and C3H/He mothers and (4) the pup strain does influence the amount of maternal behavior shown by both mothers in interstrain cross-fostering. These latter findings demonstrate that both mother strain and pup strain are key determinants of maternal behavior.
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Affiliation(s)
- R van der Veen
- INSERM, U862, University Of Bordeaux 2, Bordeaux, France
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Koehl M, Meerlo P, Gonzales D, Rontal A, Turek FW, Abrous DN. Exercise-induced promotion of hippocampal cell proliferation requires beta-endorphin. FASEB J 2008; 22:2253-62. [PMID: 18263701 DOI: 10.1096/fj.07-099101] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Adult hippocampal neurogenesis is influenced by a variety of stimuli, including exercise, but the mechanisms by which running affects neurogenesis are not yet fully understood. Because beta-endorphin, which is released in response to exercise, increases cell proliferation in vitro, we hypothesized that it could exert a similar effect in vivo and mediate the stimulatory effects of running on neurogenesis. We thus analyzed the effects of voluntary wheel-running on adult neurogenesis (proliferation, differentiation, survival/death) in wild-type and beta-endorphin-deficient mice. In wild-type mice, exercise promoted cell proliferation evaluated by sacrificing animals 24 h after the last 5-bromo-2'-deoxyuridine (BrdU) pulse and by using endogenous cell cycle markers (Ki67 and pH(3)). This was accompanied by an increased survival of 4-wk-old BrdU-labeled cells, leading to a net increase of neurogenesis. Beta-endorphin deficiency had no effect in sedentary mice, but it completely blocked the running-induced increase in cell proliferation; this blockade was accompanied by an increased survival of 4-wk-old cells and a decreased cell death. Altogether, adult neurogenesis was increased in response to exercise in knockout mice. We conclude that beta-endorphin released during running is a key factor for exercise-induced cell proliferation and that a homeostatic balance may regulate the final number of new neurons.
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Affiliation(s)
- M Koehl
- Centre de Recherche INSERM U862, Physiopathologie de la Plasticité Neuronale, 146 Rue Léo Saignat, 33077 Bordeaux Cedex, France.
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Abstract
Aging is accompanied by an alteration of spatial memory, which has been related to an alteration in hippocampal plasticity. Within the dentate gyrus, new neurons are generated throughout the entire life of an individual. This neurogenesis seems to play a role in hippocampal-mediated learning and learning-induced changes in neurogenesis have been proposed to be involved in memory. However, in aged rats, little is known on the influence of learning on the early development of the adult-born neurons and on the possible involvement of learning-induced changes in neurogenesis in age-related memory deficits. To address this issue, we took advantage of the existence of spontaneous individual differences for performances observed in aged subjects in the water maze. In this task, learning can be divided into two phases, an early phase during which performances quickly improve, and a late phase during which asymptotic levels of performances are reached. We show that the influence of spatial learning on the survival of the newly born cells depends on their birth date and the memory abilities of the aged rats. In aged rats with preserved spatial memory, learning increases the survival of cells generated before learning whereas it decreases survival of cells produced during the early phase of learning. These results highlight the importance of learning-induced changes in adult-born cell survival in memory. Furthermore, they provide new insights on the possible neural mechanisms of aging of cognitive functions and show that an alteration to the steps leading to neurogenesis may be involved in the determination of individual memory abilities.
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Affiliation(s)
- Elodie Drapeau
- Institut National de la Santé et de la Recherche Médicale U862, Bordeaux Neuroscience Research Center, University of Bordeaux 2, Bordeaux, France
| | - Marie-Françoise Montaron
- Institut National de la Santé et de la Recherche Médicale U862, Bordeaux Neuroscience Research Center, University of Bordeaux 2, Bordeaux, France
| | - Sylvie Aguerre
- Institut National de la Santé et de la Recherche Médicale U862, Bordeaux Neuroscience Research Center, University of Bordeaux 2, Bordeaux, France
| | - Djoher Nora Abrous
- Institut National de la Santé et de la Recherche Médicale U862, Bordeaux Neuroscience Research Center, University of Bordeaux 2, Bordeaux, France
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Lopez-Fernandez MA, Montaron MF, Varea E, Rougon G, Venero C, Abrous DN, Sandi C. Upregulation of polysialylated neural cell adhesion molecule in the dorsal hippocampus after contextual fear conditioning is involved in long-term memory formation. J Neurosci 2007; 27:4552-61. [PMID: 17460068 PMCID: PMC6673006 DOI: 10.1523/jneurosci.0396-07.2007] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The role of the hippocampus in pavlovian fear conditioning is controversial. Although lesion and pharmacological inactivation studies have suggested a key role for the dorsal hippocampus in contextual fear conditioning, the involvement of the ventral part is still uncertain. Likewise, the debate is open with regard to the putative implication of each hippocampal subdivision in fear conditioning to a discrete conditioned stimulus. We explored the potential existence of dissociations occurring in the dorsal versus ventral hippocampus at the cellular level while dealing with either contextual or cued fear conditioning and focused in a molecular "signature" linked to structural plasticity, the polysialylated form of the neural cell adhesion molecule (PSA-NCAM). We found an upregulation of PSA-NCAM expression in the dorsal (but not ventral) dentate gyrus at 24 h after contextual (but not tone) fear conditioning. Specific removal of PSA through microinfusion of the enzyme endoneuraminidase-N in the dorsal (but not ventral) hippocampus reduced freezing responses to the conditioned context. Therefore, we present evidence for a specific role of PSA-NCAM in the dorsal hippocampus in the plasticity processes occurring during consolidation of the context representation after "standard" contextual fear conditioning. Interestingly, we also found that exposing animals just to the context induced an activation of PSA-NCAM in both dorsal and ventral dentate gyrus. Altogether, these findings highlighting the distinctive occurrence of these neuroplastic processes in the dorsal hippocampus during the standard contextual fear-conditioning task enlighten the ongoing debate about the involvement of these hippocampal subdivisions in pavlovian fear conditioning.
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Affiliation(s)
| | - Marie-Françoise Montaron
- Neurogenesis and Pathophysiology Laboratory, Bordeaux Neuroscience Research Center, Institut National de la Santé et de la Recherche Médicale 862 and University of Bordeaux 2, Bordeaux Cedex 33077, France
| | - Emilio Varea
- Brain Mind Institute, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland
| | - Genevieve Rougon
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 6216, Université de la Méditerranée, Institut de Biologie du Développement de Marseille-Luminy Case 907, Marseille Cedex 13288, France
| | - Cesar Venero
- Psychobiology Department, Universidad Nacional de Educacion a Distancia, 28040 Madrid, Spain, and
| | - Djoher Nora Abrous
- Neurogenesis and Pathophysiology Laboratory, Bordeaux Neuroscience Research Center, Institut National de la Santé et de la Recherche Médicale 862 and University of Bordeaux 2, Bordeaux Cedex 33077, France
| | - Carmen Sandi
- Brain Mind Institute, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland
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Markram K, Lopez Fernandez MA, Abrous DN, Sandi C. Amygdala upregulation of NCAM polysialylation induced by auditory fear conditioning is not required for memory formation, but plays a role in fear extinction. Neurobiol Learn Mem 2007; 87:573-82. [PMID: 17223582 DOI: 10.1016/j.nlm.2006.11.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2006] [Revised: 11/20/2006] [Accepted: 11/28/2006] [Indexed: 10/23/2022]
Abstract
There is much interest to understand the mechanisms leading to the establishment, maintenance, and extinction of fear memories. The amygdala has been critically involved in the processing of fear memories and a number of molecular changes have been implicated in this brain region in relation to fear learning. Although neural cell adhesion molecules (NCAMs) have been hypothesized to play a role, information available about their contribution to fear memories is scarce. We investigate here whether polysialylated NCAM (PSA-NCAM) contributes to auditory fear conditioning in the amygdala. First, PSA-NCAM expression was evaluated in different amygdala nuclei after auditory fear conditioning at two different shock intensities. Results showed that PSA-NCAM expression was increased 24 h post-training only in animals subjected to the highest shock intensity (1mA). Second, PSA-NCAM was cleaved in the basolateral amygdaloid complex through micro-infusions of the enzyme endoneuraminidase N, and the consequences of such treatment were investigated on the acquisition, consolidation, remote memory expression, and extinction of conditioned fear memories. Intra-amygdaloid cleavage of PSA-NCAM did not affect acquisition, consolidation or expression of remote fear memories. However, intra-amygdaloid PSA-NCAM cleavage enhanced fear extinction processes. These results suggest that upregulation of PSA-NCAM is a correlate of fear conditioning that is not necessary for the establishment of fear memory in the amygdala, but participates in mechanisms precluding fear extinction. These findings point out PSA-NCAM as a potential target for the treatment of psychopathologies that involve impairment in fear extinction.
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Affiliation(s)
- Kamila Markram
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Switzerland
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Lemaire V, Lamarque S, Le Moal M, Piazza PV, Abrous DN. Postnatal stimulation of the pups counteracts prenatal stress-induced deficits in hippocampal neurogenesis. Biol Psychiatry 2006; 59:786-92. [PMID: 16460692 DOI: 10.1016/j.biopsych.2005.11.009] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 09/09/2005] [Accepted: 11/30/2005] [Indexed: 11/22/2022]
Abstract
BACKGROUND Prenatal stress constitutes a developmental risk factor for later psychopathology. The behavioral disorders are sustained by neurobiological alterations including long-term reduction of hippocampal neurogenesis; its deregulation has been involved in cognitive impairments, mood disorders and addiction. A major goal is to define periods in development and strategies for intervening to prevent the effects of early stressful events. We investigated the ability of a postnatal infantile stimulation to prevent prenatal stress-induced alteration in hippocampal neurogenesis. METHODS The influence of postnatal handling on prenatal stress-induced changes in hippocampal neurogenesis was examined in 4 and 26 month-old male rats. Three distinct phases of the neurogenesis were studied: proliferation, survival and neuronal differentiation. RESULTS Prenatal stress reduced hippocampal cell proliferation all throughout life. Furthermore, the survival rate of newborn cells, the number of immature neurons and the number of differentiated new neurons were reduced in young and old prenatally-stressed rats. All those deleterious effects were counteracted by neonatal handling. CONCLUSIONS These data show that finer aspects of brain shaping can be rewired by environmental influences occurring at sensitive phase of development. They also suggest that infantile stimulation may reverse the appearance of behavioral disorders induced by early life stress.
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Affiliation(s)
- Valerie Lemaire
- Institut National de la Santé et de la Recherche Médicale U588, Institut François Magendie, University of Bordeaux II, Bordeaux Cedex, France
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Montaron MF, Drapeau E, Dupret D, Kitchener P, Aurousseau C, Le Moal M, Piazza PV, Abrous DN. Lifelong corticosterone level determines age-related decline in neurogenesis and memory. Neurobiol Aging 2006; 27:645-54. [PMID: 15953661 DOI: 10.1016/j.neurobiolaging.2005.02.014] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2004] [Revised: 01/04/2005] [Accepted: 02/24/2005] [Indexed: 10/25/2022]
Abstract
Ageing is accompanied by an alteration of spatial memory, a decline in hippocampal neurogenesis and a dysregulation of the hypothalamic-pituitary axis (HPA) leading to elevated levels of circulating corticosterone. However, the role of the HPA axis in age-related decline in cognitive functions and in neurogenesis decline remains unclear. We found that suppression of glucocorticoids secretion from midlife to the rest of the animals' life increases neurogenesis in old animals and prevents the emergence of age-related memory disorders. Reciprocally, aged rats with a chronic upregulation of the HPA axis exhibit not only spatial memory impairments but also very low levels of hippocampal cell proliferation and survival. Altogether, these results indicate that the extent of lifetime exposure to glucocorticoids determines the extent of age-related decline in hippocampal neurogenesis and consequently age-related cognitive dysfunctions.
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Affiliation(s)
- M F Montaron
- Laboratoire de Physiopathologie du Comportement, I.N.S.E.R.M. Unité 588, Université de Bordeaux II, Domaine de Carreire, 146, rue Léo. Saignat, 33077 Bordeaux Cedex, France
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Dupret D, Montaron MF, Drapeau E, Aurousseau C, Le Moal M, Piazza PV, Abrous DN. Methylazoxymethanol acetate does not fully block cell genesis in the young and aged dentate gyrus. Eur J Neurosci 2005; 22:778-83. [PMID: 16101760 DOI: 10.1111/j.1460-9568.2005.04262.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
During adulthood, new neurons are continuously added to the mammalian dentate gyrus (DG). An increasing number of studies have correlated changes in rates of dentate neurogenesis with memory abilities. One study based on subchronic treatment with the toxin methylazoxymethanol acetate (MAM) has provided causal evidence that neurogenesis is involved in hippocampal-dependent trace conditioning. In contrast, spatial learning is not impaired following MAM treatment. We hypothesized that this was due to the small residual number of new cells produced following MAM treatment. In the present experiment, we attempted to achieve a higher level of reduction of adult-generated cells following MAM treatment in young and aged rats. We found only a partial reduction of adult-generated cells in the DG. More importantly, independently of the age of the animals, MAM treatment at a dose necessary to reduce neurogenesis altered the overall health of the animals. In conclusion, the behavioural results obtained following subchronic treatment with high doses of MAM in adulthood must be interpreted with extreme caution.
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Affiliation(s)
- David Dupret
- INSERM U588, University of Bordeaux II, Institute F Magendie, 146 rue Léo-Saignat, 33077 Bordeaux Cedex, France
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Abstract
The discovery that the adult mammalian brain creates new neurons from pools of stemlike cells was a breakthrough in neuroscience. Interestingly, this particular new form of structural brain plasticity seems specific to discrete brain regions, and most investigations concern the subventricular zone (SVZ) and the dentate gyrus (DG) of the hippocampal formation (HF). Overall, two main lines of research have emerged over the last two decades: the first aims to understand the fundamental biological properties of neural stemlike cells (and their progeny) and the integration of the newly born neurons into preexisting networks, while the second focuses on understanding its relevance in brain functioning, which has been more extensively approached in the DG. Here, we propose an overview of the current knowledge on adult neurogenesis and its functional relevance for the adult brain. We first present an analysis of the methodological issues that have hampered progress in this field and describe the main neurogenic sites with their specificities. We will see that despite considerable progress, the levels of anatomic and functional integration of the newly born neurons within the host circuitry have yet to be elucidated. Then the intracellular mechanisms controlling neuronal fate are presented briefly, along with the extrinsic factors that regulate adult neurogenesis. We will see that a growing list of epigenetic factors that display a specificity of action depending on the neurogenic site under consideration has been identified. Finally, we review the progress accomplished in implicating neurogenesis in hippocampal functioning under physiological conditions and in the development of hippocampal-related pathologies such as epilepsy, mood disorders, and addiction. This constitutes a necessary step in promoting the development of therapeutic strategies.
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Affiliation(s)
- Djoher Nora Abrous
- Laboratoire de Physiopathologie des Comportements, Institut National de la Sané et de la Recherche Médicale, U588, Université de Bordeaux, France.
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44
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Mayo W, Lemaire V, Malaterre J, Rodriguez JJ, Cayre M, Stewart MG, Kharouby M, Rougon G, Le Moal M, Piazza PV, Abrous DN. Pregnenolone sulfate enhances neurogenesis and PSA-NCAM in young and aged hippocampus. Neurobiol Aging 2005; 26:103-14. [PMID: 15585350 DOI: 10.1016/j.neurobiolaging.2004.03.013] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2003] [Revised: 02/11/2004] [Accepted: 03/11/2004] [Indexed: 01/03/2023]
Abstract
Age-dependent cognitive impairments have been correlated with functional and structural modifications in the hippocampal formation. In particular, the brain endogenous steroid pregnenolone-sulfate (Preg-S) is a cognitive enhancer whose hippocampal levels have been linked physiologically to cognitive performance in senescent animals. However, the mechanism of its actions remains unknown. Because neurogenesis is sensitive to hormonal influences, we examined the effect of Preg-S on neurogenesis, a novel form of plasticity, in young and old rats. We demonstrate that in vivo infusion of Preg-S stimulates neurogenesis and the expression of the polysialylated forms of NCAM, PSA-NCAM, in the dentate gyrus of 3- and 20-month-old rats. These influences on hippocampal plasticity are mediated by the modulation of the gamma-aminobutyric acid receptor complex A (GABA(A)) receptors present on hippocampal neuroblasts. In vitro, Preg-S stimulates the division of adult-derived spheres suggesting a direct influence on progenitors. These data provide evidence that neurosteroids represent one of the local secreted signals controlling hippocampal neurogenesis. Thus, therapies which stimulate neurosteroidogenesis could preserve hippocampal plasticity and prevent the appearance of age-related cognitive disturbances.
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Affiliation(s)
- W Mayo
- Laboratoire de Psychobiologie des Comportements Adaptatifs, INSERM U588, Domaine de Carreire, Rue Camille Saint-Saëns, 33077 Bordeaux, France
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45
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Montaron MF, Koehl M, Lemaire V, Drapeau E, Abrous DN, Le Moal M. Environmentally induced long-term structural changes: cues for functional orientation and vulnerabilities. Neurotox Res 2004; 6:571-80. [PMID: 15639789 DOI: 10.1007/bf03033453] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Environmental challenges profoundly modify phenotypes and disrupt inherent developmental programs both at functional and structural levels. As an example, we have studied the impact of these environmental influences on adult neurogenesis in the dentate gyrus. Neurogenesis results from an inherent program, participates to hippocampal network organization and, as a consequence, to the various functional abilities depending on this region, including memories. In preclinical studies of aging we have shown that phenotypes vulnerable to the development of spatial memory disorders are characterized by lower hippocampal neurogenesis. We have hypothesized that these interindividual variations in functional expression of neurogenesis in senescent subjects could be predicted early in life. Indeed, a behavioral response (novelty-induced locomotor reactivity) and a biological trait (hypothalamo-pituitary-adrenal axis activity), which are predictive of cognitive impairments later in life, are related to neurogenesis in young adult rats. This suggests that subjects starting off with an impaired neurogenesis, here rats that are high reactive to stress, are predisposed for the development of age-related cognitive disorders. We have further shown that these inter-individual differences result from early deleterious life events. Indeed, prenatal stress orients neurogenesis in pathological ways for the entire life, and precipitates age-related cognitive impairments. Altogether these data suggest first that hippocampal neurogenesis plays a pivotal role in environmentally-induced vulnerability to the development of pathological aging, and second that environmental challenges and life events orient structural developments, leading to different phenotypes.
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Affiliation(s)
- M F Montaron
- INSERM U588, Domaine de Carreire, Rue Camille Saint Saëns, University of Bordeaux II Bordeaux Cedex 33077, France
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Montaron MF, Piazza PV, Aurousseau C, Urani A, Le Moal M, Abrous DN. Implication of corticosteroid receptors in the regulation of hippocampal structural plasticity. Eur J Neurosci 2003; 18:3105-11. [PMID: 14656306 DOI: 10.1111/j.1460-9568.2003.03048.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The dentate gyrus is one of the few areas of the adult brain that continues to produce neurons and to express the embryonic polysialylated isoforms of neuronal cell adhesion molecules (PSA-NCAM). The stress hormone corticosterone exerts a complex modulation on neurogenesis and PSA-NCAM, and previous studies have shown that mature granule cells require corticosterone for their survival. Thus, the aim of our work was to investigate the respective role of the different corticosteroid receptors on these three parameters in adrenalectomized rats. It was found that treatment with a low dose of the mineralocorticoid receptor agonist, aldosterone, prevents only the adrenalectomy-induced increase in cell death. Treatment with a higher dose of aldosterone normalized cell proliferation whereas PSA-NCAM expression was normalized only by treatment with the glucocorticoid receptor agonist, RU 28362. It is concluded that stimulation of the mineralocorticoid receptor is sufficient to mediate the effects of corticosterone on neurogenesis and to protect mature cells from cell death whereas stimulation of the glucocorticoid receptor is necessary to modulate PSA-NCAM expression.
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Affiliation(s)
- M F Montaron
- INSERM U588, Rue Camille Saint Saëns, 33 077, Bordeaux Cedex, France
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Drapeau E, Mayo W, Aurousseau C, Le Moal M, Piazza PV, Abrous DN. Spatial memory performances of aged rats in the water maze predict levels of hippocampal neurogenesis. Proc Natl Acad Sci U S A 2003; 100:14385-90. [PMID: 14614143 PMCID: PMC283601 DOI: 10.1073/pnas.2334169100] [Citation(s) in RCA: 488] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2003] [Accepted: 09/26/2003] [Indexed: 12/12/2022] Open
Abstract
Neurogenesis occurs within the adult dentate gyrus of the hippocampal formation and it has been proposed that the newly born neurons, recruited into the preexistent neuronal circuits, might be involved in hippocampal-dependent learning processes. Age-dependent spatial memory impairments have been related to an alteration in hippocampal plasticity. The aim of the current study was to examine whether cognitive functions in aged rats are quantitatively correlated with hippocampal neurogenesis. To this end, we took advantage of the existence of spontaneous individual differences observed in aged subjects in a hippocampal-dependent task, the water maze. We expected that the spatial memory capabilities of aged rats would be related to the levels of hippocampal neurogenesis. Old rats were trained in the water maze, and, 3 weeks after training, rats were injected with 5-bromo-2'-deoxyuridine (BrdUrd, 50 or 150 mg/kg) to label dividing cells. Cell proliferation was examined one day after the last BrdUrd injection, whereas cell survival and differentiation were determined 3 weeks later. It is shown that a quantitative relationship exists between learning and the number of newly generated neurons. Animals with preserved spatial memory, i.e., the aged-unimpaired rats, exhibited a higher level of cell proliferation and a higher number of new neurons in comparison with rats with spatial memory impairments, i.e., the aged-impaired rats. In conclusion, the extent of memory dysfunction in aged rats is quantitatively related to the hippocampal neurogenesis. These data reinforce the assumption that neurogenesis is involved in memory processes and aged-related cognitive alterations.
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Affiliation(s)
- Elodie Drapeau
- Institut National de la Santá et de la Recherche Médicale Unité 588, Domaine de Carreire, Rue Camille Saint Saëns, University of Bordeaux II, 33077 Bordeaux Cedex, France
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Döbrössy MD, Drapeau E, Aurousseau C, Le Moal M, Piazza PV, Abrous DN. Differential effects of learning on neurogenesis: learning increases or decreases the number of newly born cells depending on their birth date. Mol Psychiatry 2003; 8:974-82. [PMID: 14647395 DOI: 10.1038/sj.mp.4001419] [Citation(s) in RCA: 199] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The hippocampal formation, to which new neurons are added on a daily basis throughout life, is important in spatial learning. Surviving de novo produced cells integrate into the functional circuitry, where they can influence both normal and pathological behaviors. In this study, we examined the effect of the water-maze (a hippocampal-dependent spatial task) on neurogenesis. Learning in this task can be divided into two phases, an early phase during which performance improves rapidly, and a late phase during which asymptotic levels of performance are reached. Here we demonstrate that the late phase of learning has a multifaceted effect on neurogenesis depending on the birth date of new neurons. The number of newly born cells increased contingently with the late phase and a large proportion of these cells survived for at least 4 weeks and differentiated into neurons. In contrast, late-phase learning decreased the number of newly born cells produced during the early phase. This decline in neurogenesis was positively correlated with performance in the water-maze. Thus, rats with the highest de novo cell number were less able to acquire and use spatial information than those with low numbers of new cells. These results show that learning has a complex effect on hippocampal neurogenesis, and reveals a novel mechanism through which neurogenesis may influence normal and pathological behaviors.
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Affiliation(s)
- M D Döbrössy
- INSERM U259, University of Bordeaux, Domaine de Carreire, Bordeaux, France
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Koehl M, Lemaire V, Mayo W, Abrous DN, Maccari S, Piazza PV, Le Moal M, Vallée M. Individual vulnerability to substance abuse and affective disorders: role of early environmental influences. Neurotox Res 2002; 4:281-96. [PMID: 12829419 DOI: 10.1080/1029842021000010866] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
One of the most important questions raised by modern psychiatry and experimental psychopathology is the origin of mental diseases. More concisely, clinical and experimental neurosciences are increasingly concerned with the factors that render one individual more vulnerable than another to a given pathological outcome. Animal models are now available to understand the sources of individual differences for specific phenotypes prone to behavioral disadaptations. Over the last 10 years we have explored the consequences of environmental perinatal manipulations in the rat. We have shown that prenatal stress is at the origin of a wide range of physiological and behavioral aberrances such as alterations in the activity of the hormonal stress axis, increased vulnerability to drug of abuse, emotional liability, cognitive impairments and predisposition to pathological aging. Taken together, these abnormalities define a bio-behavioral syndrome. Furthermore, the cognitive disabilities observed in prenatally-stressed rats were recently related to an alteration of neurogenesis in the dentate gyrus, thus confirming the impact of early life events on brain morphology. A second model (handling model) has also been developed in which pups are briefly separated from their mothers during early postnatal life. In contrast with prenatally-stressed animals, handled rats exhibited a reduced emotion response when confronted with novel situations and were protected against age-induced impairments of both the hormonal stress axis and cognitive functions. Taken together, the results of these investigations show that the bio-behavioral phenotype that characterizes each individual is strongly linked to the nature and timing of perinatal experience. Furthermore, data collected in prenatally-stressed animals indicate that this model could be used profitably to understand the etiology and pathophysiology of affective disorders.
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Affiliation(s)
- Muriel Koehl
- Laboratoire de Psychobiologie des Comportements Adaptatifs - INSERM U.259, Université Victor Ségalen Bordeaux 2, Institut François Magendie, Rue Camille Saint-Saëns, 33077 Bordeaux Cedex, France.
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Abstract
Neurosteroids are a subclass of steroids that can be synthesized in the central nervous system independently of peripheral sources. Several neurosteroids influence cognitive functions. Indeed, in senescent animals we have previously demonstrated a significant correlation between the cerebral concentration of pregnenolone sulfate (PREG-S) and cognitive performance. Indeed, rats with memory impairments exhibited low PREG-S concentrations compared to animals with correct memory performance. Furthermore, these memory deficits can be reversed by intracerebral infusions of PREG-S. Neurotransmitter systems modulated by this neurosteroid were unknown until our recent report of an enhancement of acetylcholine (ACh) release in basolateral amygdala, cortex, and hippocampus induced by central administrations of PREG-S. Central ACh neurotransmission is involved in the regulation of memory processes and is affected in normal aging and in human neurodegenerative pathologies like Alzheimer's disease. ACh neurotransmission is also involved in the modulation of sleep-wakefulness cycle and relationships between paradoxical sleep and memory are well documented in the literature. PREG-S infused at the level of ACh cell bodies induces a dramatic increase of paradoxical sleep in young animals. Cognitive dysfunctions, particularly those observed in Alzheimer's disease, have also been related to alterations of cerebral plasticity. Among these mechanisms, neurogenesis has been recently studied. Preliminary data suggest that PREG-S central infusions dramatically increase neurogenesis. Taken together these data suggest that PREG-S can influence cognitive processes, particularly in senescent subjects, through a modulation of ACh neurotransmission associated with paradoxical sleep modifications; furthermore our recent data suggest a role for neurosteroids in the modulation of hippocampal neurogenesis.
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Affiliation(s)
- W Mayo
- INSERM U259, Institut François Magendie, Rue Camille Saint-Saens, 33077 Bordeaux Cedex, France.
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