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Martínez-Canabal A, López-Oropeza G, Sotres-Bayón F. Hippocampal neurogenesis facilitates cognitive flexibility in a fear discrimination task. Front Behav Neurosci 2024; 17:1331928. [PMID: 38282713 PMCID: PMC10813213 DOI: 10.3389/fnbeh.2023.1331928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 12/18/2023] [Indexed: 01/30/2024] Open
Abstract
Hippocampal neurogenesis, the continuous creation of new neurons in the adult brain, influences memory, regulates the expression of defensive responses to threat (fear), and cognitive processes like pattern separation and behavioral flexibility. One hypothesis proposes that neurogenesis promotes cognitive flexibility by degrading established memories and promoting relearning. Yet, empirical evidence on its role in fear discrimination tasks is scarce. In this study, male rats were initially trained to differentiate between two similar environments, one associated with a threat. Subsequently, we enhanced neurogenesis through environmental enrichment and memantine treatments. We then reversed the emotional valence of these contexts. In both cases, neurogenesis improved the rats' ability to relearn the aversive context. Interestingly, we observed increased hippocampal activity, and decreased activity in the prelimbic cortex and lateral habenula, while the infralimbic cortex remained unchanged, suggesting neurogenesis-induced plasticity changes in this brain network. Moreover, when we pharmacologically inhibited the increased neurogenesis with Methotrexate, rats struggled to relearn context discrimination, confirming the crucial role of neurogenesis in this cognitive process. Overall, our findings highlight neurogenesis's capacity to facilitate changes in fear discrimination and emphasize the involvement of a prefrontal-hippocampal-habenula mechanism in this process. This study emphasizes the intricate relationship between hippocampal neurogenesis, cognitive flexibility, and the modulation of fear-related memories.
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Affiliation(s)
- Alonso Martínez-Canabal
- Department of Cell Biology, Faculty of Sciences, National Autonomous University of Mexico (UNAM), México City, Mexico
- Cell Physiology Institute - Neuroscience, National Autonomous University of Mexico (UNAM), México City, Mexico
| | - Grecia López-Oropeza
- Department of Cell Biology, Faculty of Sciences, National Autonomous University of Mexico (UNAM), México City, Mexico
- Cell Physiology Institute - Neuroscience, National Autonomous University of Mexico (UNAM), México City, Mexico
- Graduate Program in Biological Sciences, National Autonomous University of Mexico (UNAM), México City, Mexico
| | - Francisco Sotres-Bayón
- Cell Physiology Institute - Neuroscience, National Autonomous University of Mexico (UNAM), México City, Mexico
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Higuchi Y, Arakawa H. Serotonergic mediation of the brain-wide neurogenesis: Region-dependent and receptor-type specific roles on neurogenic cellular transformation. CURRENT RESEARCH IN NEUROBIOLOGY 2023; 5:100102. [PMID: 37638344 PMCID: PMC10458724 DOI: 10.1016/j.crneur.2023.100102] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 06/18/2023] [Accepted: 07/15/2023] [Indexed: 08/29/2023] Open
Abstract
Brain serotonin (5-hydroxytryptamine, 5-HT) is a key molecule for the mediation of depression-related brain states, but the neural mechanisms underlying 5-HT mediation need further investigation. A possible mechanism of the therapeutic antidepressant effects is neurogenic cell production, as stimulated by 5-HT signaling. Neurogenesis, the proliferation of neural stem cells (NSCs), and cell differentiation and maturation occur across brain regions, particularly the hippocampal dentate gyrus and the subventricular zone, throughout one's lifespan. 5-HT plays a major role in the mediation of neurogenic processes, which in turn leads to the therapeutic effect on depression-related states. In this review article, we aim to identify how the neuronal 5-HT system mediates the process of neurogenesis, including cell proliferation, cell-type differentiation and maturation. First, we will provide an overview of the neurogenic cell transformation that occurs in brain regions containing or lacking NSCs. Second, we will review brain region-specific mechanisms of 5-HT-mediated neurogenesis by comparing regions localized to NSCs, i.e., the hippocampus and subventricular zone, with those not containing NSCs. Highlighting these 5-HT mechanisms that mediate neurogenic cell production processes in a brain-region-specific manner would provide unique insights into the role of 5-HT in neurogenesis and its associated effects on depression.
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Affiliation(s)
- Yuki Higuchi
- Department of Systems Physiology, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Hiroyuki Arakawa
- Department of Systems Physiology, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
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3
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Blanco-Luquin I, Acha B, Urdánoz-Casado A, Gómez-Orte E, Roldan M, Pérez-Rodríguez DR, Cabello J, Mendioroz M. NXN Gene Epigenetic Changes in an Adult Neurogenesis Model of Alzheimer's Disease. Cells 2022; 11:cells11071069. [PMID: 35406633 PMCID: PMC8998146 DOI: 10.3390/cells11071069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/17/2022] [Accepted: 03/20/2022] [Indexed: 12/10/2022] Open
Abstract
In view of the proven link between adult hippocampal neurogenesis (AHN) and learning and memory impairment, we generated a straightforward adult neurogenesis in vitro model to recapitulate DNA methylation marks in the context of Alzheimer’s disease (AD). Neural progenitor cells (NPCs) were differentiated for 29 days and Aβ peptide 1–42 was added. mRNA expression of Neuronal Differentiation 1 (NEUROD1), Neural Cell Adhesion Molecule 1 (NCAM1), Tubulin Beta 3 Class III (TUBB3), RNA Binding Fox-1 Homolog 3 (RBFOX3), Calbindin 1 (CALB1), and Glial Fibrillary Acidic Protein (GFAP) was determined by RT-qPCR to characterize the culture and framed within the multistep process of AHN. Hippocampal DNA methylation marks previously identified in Contactin-Associated Protein 1 (CNTNAP1), SEPT5-GP1BB Readthrough (SEPT5-GP1BB), T-Box Transcription Factor 5 (TBX5), and Nucleoredoxin (NXN) genes were profiled by bisulfite pyrosequencing or bisulfite cloning sequencing; mRNA expression was also measured. NXN outlined a peak of DNA methylation overlapping type 3 neuroblasts. Aβ-treated NPCs showed transient decreases of mRNA expression for SEPT5-GP1BB and NXN on day 9 or 19 and an increase in DNA methylation on day 29 for NXN. NXN and SEPT5-GP1BB may reflect alterations detected in the brain of AD human patients, broadening our understanding of this disease.
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Affiliation(s)
- Idoia Blanco-Luquin
- Neuroepigenetics Laboratory-Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA (Navarra Institute for Health Research), 31008 Pamplona, Spain; (B.A.); (A.U.-C.); (M.R.); (M.M.)
- Correspondence: ; Tel.: +34-848425739
| | - Blanca Acha
- Neuroepigenetics Laboratory-Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA (Navarra Institute for Health Research), 31008 Pamplona, Spain; (B.A.); (A.U.-C.); (M.R.); (M.M.)
| | - Amaya Urdánoz-Casado
- Neuroepigenetics Laboratory-Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA (Navarra Institute for Health Research), 31008 Pamplona, Spain; (B.A.); (A.U.-C.); (M.R.); (M.M.)
| | - Eva Gómez-Orte
- CIBIR (Center for Biomedical Research of La Rioja), 26006 Logroño, Spain; (E.G.-O.); (J.C.)
| | - Miren Roldan
- Neuroepigenetics Laboratory-Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA (Navarra Institute for Health Research), 31008 Pamplona, Spain; (B.A.); (A.U.-C.); (M.R.); (M.M.)
| | - Diego R. Pérez-Rodríguez
- Neurophysiology Department, Hospital Universitario de Navarra (HUN), IdiSNA (Navarra Institute for Health Research), 31008 Pamplona, Spain;
| | - Juan Cabello
- CIBIR (Center for Biomedical Research of La Rioja), 26006 Logroño, Spain; (E.G.-O.); (J.C.)
| | - Maite Mendioroz
- Neuroepigenetics Laboratory-Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), IdiSNA (Navarra Institute for Health Research), 31008 Pamplona, Spain; (B.A.); (A.U.-C.); (M.R.); (M.M.)
- Department of Neurology, Hospital Universitario de Navarra (HUN), IdiSNA (Navarra Institute for Health Research), 31008 Pamplona, Spain
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Expression of Doublecortin, Glial Fibrillar Acidic Protein, and Vimentin in the Intact Subpallium and after Traumatic Injury to the Pallium in Juvenile Salmon, Oncorhynchus masou. Int J Mol Sci 2022; 23:ijms23031334. [PMID: 35163257 PMCID: PMC8836249 DOI: 10.3390/ijms23031334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/17/2022] [Accepted: 01/22/2022] [Indexed: 02/04/2023] Open
Abstract
Fetalization associated with a delay in development and the preservation of the features of the embryonic structure of the brain dominates the ontogeny of salmonids. The aim of the present study was to comparatively analyze the distribution of the glial-type aNSC markers such as vimentin and glial fibrillar acidic protein (GFAP) and the migratory neuronal precursors such as doublecortin in the telencephalon subpallium of juvenile masu salmon, Oncorhynchus masou, in normal conditions and at 1 week after an injury to the dorsal pallium. Immunohistochemical labeling of vimentin, GFAP, and doublecortin in the pallium of intact juvenile masu salmon revealed single cells with similar morphologies corresponding to a persistent pool of neuronal and/or glial progenitors. The study of the posttraumatic process showed the presence of intensely GFAP-labeled cells of the neuroepithelial type that form reactive neurogenic zones in all areas of the subpallial zone of juvenile masu salmon. A comparative analysis of the distribution of radial glia in the dorsal, ventral, and lateral zones of the subpallium showed a maximum concentration of cells in the dorsal part of subpallium (VD) and a minimum concentration in the lateral part of subpallium VL. An essential feature of posttraumatic immunolabeling in the masu salmon subpallium is the GFAP distribution patterns that are granular intracellular in the apical periventricular zone (PVZ) and fibrillar extracellular in the subventricular (SVZ) and parenchymal zones (PZ). In contrast to those in intact animals, most of the GFAP+ granules and constitutive neurogenic niches in injured fish were localized in the basal part of the PVZ. With the traumatic injury to the subpallium, the number of Vim+ cells in the lateral and ventral regions significantly increased. At 1 week post-injury, the total immunolabeling of vimentin cells in the PVZ was replaced by the granular pattern of Vim immunodistribution spreading from the PVZ to the SVZ and deeper parenchymal layers of the brain in all areas of the subpallium. A significant increase in the number of DC+ cells was observed also in all areas of the subpallium. The number of cells increased both in the PVZ and in the SVZ, as well as in the deeper PZ. Thus, at 1 week after the injury to the dorsal pallium, the number of DC, Vim, and GFAP expressing cells of the neuroepithelial type in the subpallium of juvenile masu salmon increased, and additionally GFAP+ radial glia appeared in VD, which was absent from intact animals.
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p27, The Cell Cycle and Alzheimer´s Disease. Int J Mol Sci 2022; 23:ijms23031211. [PMID: 35163135 PMCID: PMC8835212 DOI: 10.3390/ijms23031211] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 12/29/2022] Open
Abstract
The cell cycle consists of successive events that lead to the generation of new cells. The cell cycle is regulated by different cyclins, cyclin-dependent kinases (CDKs) and their inhibitors, such as p27Kip1. At the nuclear level, p27Kip1 has the ability to control the evolution of different phases of the cell cycle and oppose cell cycle progression by binding to CDKs. In the cytoplasm, diverse functions have been described for p27Kip1, including microtubule remodeling, axonal transport and phagocytosis. In Alzheimer’s disease (AD), alterations to cycle events and a purported increase in neurogenesis have been described in the early disease process before significant pathological changes could be detected. However, most neurons cannot progress to complete their cell division and undergo apoptotic cell death. Increased levels of both the p27Kip1 levels and phosphorylation status have been described in AD. Increased levels of Aβ42, tau hyperphosphorylation or even altered insulin signals could lead to alterations in p27Kip1 post-transcriptional modifications, causing a disbalance between the levels and functions of p27Kip1 in the cytoplasm and nucleus, thus inducing an aberrant cell cycle re-entry and alteration of extra cell cycle functions. Further studies are needed to completely understand the role of p27Kip1 in AD and the therapeutic opportunities associated with the modulation of this target.
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Molecular Markers of Adult Neurogenesis in the Telencephalon and Tectum of Rainbow Trout, Oncorhynchus mykiss. Int J Mol Sci 2022; 23:ijms23031188. [PMID: 35163116 PMCID: PMC8835435 DOI: 10.3390/ijms23031188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/17/2022] [Accepted: 01/17/2022] [Indexed: 12/04/2022] Open
Abstract
In the brain of teleost fish, radial glial cells are the major type of astroglial cells. To answer the question as to how radial glia structures adapt to the continuous growth of the brain, which is characteristic of salmonids, it is necessary to study various types of cells (neuronal precursors, astroglial cells, and cells in a state of neuronal differentiation) in the major integrative centers of the salmon brain (telencephalon and tectum opticum), using rainbow trout, Oncorhynchus mykiss, as a model. A study of the distribution of several molecular markers in the telencephalon and tectum with the identification of neural stem/progenitor cells, neuroblasts, and radial glia was carried out on juvenile (three-year-old) O. mykiss. The presence of all of these cell types provides specific conditions for the adult neurogenesis processes in the trout telencephalon and tectum. The distribution of glutamine synthetase, a molecular marker of neural stem cells, in the trout telencephalon revealed a large population of radial glia (RG) corresponding to adult-type neural stem cells (NSCs). RG dominated the pallial region of the telencephalon, while, in the subpallial region, RG was found in the lateral and ventral zones. In the optic tectum, RG fibers were widespread and localized both in the marginal layer and in the periventricular gray layer. Doublecortin (DC) immunolabeling revealed a large population of neuroblasts formed in the postembryonic period, which is indicative of intense adult neurogenesis in the trout brain. The pallial and subpallial regions of the telencephalon contained numerous DC+ cells and their clusters. In the tectum, DC+ cells were found not only in the stratum griseum periventriculare (SGP) and longitudinal torus (TL) containing proliferating cells, but also in the layers containing differentiated neurons: the central gray layer, the periventricular gray and white layers, and the superficial white layer. A study of the localization patterns of vimentin and nestin in the trout telencephalon and tectum showed the presence of neuroepithelial neural stem cells (eNSCs) and ependymoglial cells in the periventricular matrix zones of the brain. The presence of vimentin and nestin in the functionally heterogeneous cell types of adult trout indicates new functional properties of these proteins and their heterogeneous involvement in intracellular motility and adult neurogenesis. Investigation into the later stages of neuronal development in various regions of the fish brain can substantially elucidate the major mechanisms of adult neurogenesis, but it can also contribute to understanding the patterns of formation of certain brain regions and the involvement of RG in the construction of the definite brain structure.
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Lee S, Lee W, Yang S, Suh YJ, Hong DG, Chang SC, Kim HS, Lee J. Di- n-butyl phthalate disrupts neuron maturation in primary rat embryo neurons and male C57BL/6 mice. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2022; 85:56-70. [PMID: 34488563 DOI: 10.1080/15287394.2021.1973631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Di-n-butyl phthalate (DBP) is commonly used as a plasticizer and its usage continues to increase in conjunction with plastic consumption. DBP is readily released into air, drinking water, and soil, and unfortunately, is a potent endocrine disrupter that impairs central nervous system functions. Previously DBP was found to (1) arrest the cell cycle of C17.2 neural progenitor cells (NPCs) at the G1 phase, (2) reduce numbers of newly generated neural stem cells in the mouse hippocampus, and (3) adversely affect learning and memory. Other investigators also noted DBP-mediated neurotoxic effects, but as yet, no study has addressed the adverse effects of DBP on neuronal differentiation. Data demonstrated that at 200 μM DBP induced apoptosis in rat embryo primary neurons by increasing reactive oxygen species levels and inducing mitochondrial dysfunction. However, no significant effect was detected on neurons at concentrations of ≤100 μM. In contrast, doublecortin/microtubule associated protein-2 (DCX/MAP2) immunocytochemistry showed that DBP at 100 μM delayed neuronal maturation by increasing protein levels of DCX (an immature neuronal marker), without markedly affecting cell viability. Further in vivo studies confirmed that DCX+ cell numbers were significantly elevated in the hippocampus of DBP-treated mice, indicating that DBP delayed neuronal maturation, which is known to be associated with impaired memory retention. Data demonstrated that DBP might disrupt neuronal maturation, which is correlated with reduced neurocognitive functions.
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Affiliation(s)
- Seulah Lee
- Department of Pharmacy, College of Pharmacy and Research Institute for Drug Development, Pusan National University, Busan, Republic of Korea
| | - Wonjong Lee
- Department of Pharmacy, College of Pharmacy and Research Institute for Drug Development, Pusan National University, Busan, Republic of Korea
- Pharmacological Research Division, Toxicological Evaluation and Research Department, National Institute Of Food And Drug Safety Evaluation, Ministry of Food and Drug Safety, Heungdeok-gu, Korea
| | - Seonguk Yang
- Department of Pharmacy, College of Pharmacy and Research Institute for Drug Development, Pusan National University, Busan, Republic of Korea
| | - Yeon Ji Suh
- Department of Pharmacy, College of Pharmacy and Research Institute for Drug Development, Pusan National University, Busan, Republic of Korea
| | - Dong Geun Hong
- Department of Pharmacy, College of Pharmacy and Research Institute for Drug Development, Pusan National University, Busan, Republic of Korea
| | - Seung-Cheol Chang
- Department of Cogno-Mechatronics Engineering, College of Nanoscience and Nanotechnology, Pusan National University, Busan, Republic of Korea
| | - Hyung Sik Kim
- School of Pharmacy, Sungkyunkwan University, Seobu-ro, Republic of Korea1
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Sekeres MJ, Bradley-Garcia M, Martinez-Canabal A, Winocur G. Chemotherapy-Induced Cognitive Impairment and Hippocampal Neurogenesis: A Review of Physiological Mechanisms and Interventions. Int J Mol Sci 2021; 22:ijms222312697. [PMID: 34884513 PMCID: PMC8657487 DOI: 10.3390/ijms222312697] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/15/2021] [Accepted: 11/20/2021] [Indexed: 12/16/2022] Open
Abstract
A wide range of cognitive deficits, including memory loss associated with hippocampal dysfunction, have been widely reported in cancer survivors who received chemotherapy. Changes in both white matter and gray matter volume have been observed following chemotherapy treatment, with reduced volume in the medial temporal lobe thought to be due in part to reductions in hippocampal neurogenesis. Pre-clinical rodent models confirm that common chemotherapeutic agents used to treat various forms of non-CNS cancers reduce rates of hippocampal neurogenesis and impair performance on hippocampally-mediated learning and memory tasks. We review the pre-clinical rodent literature to identify how various chemotherapeutic drugs affect hippocampal neurogenesis and induce cognitive impairment. We also review factors such as physical exercise and environmental stimulation that may protect against chemotherapy-induced neurogenic suppression and hippocampal neurotoxicity. Finally, we review pharmacological interventions that target the hippocampus and are designed to prevent or reduce the cognitive and neurotoxic side effects of chemotherapy.
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Affiliation(s)
- Melanie J. Sekeres
- School of Psychology, University of Ottawa, Ottawa, ON K1N 6N5, Canada;
- Correspondence:
| | | | - Alonso Martinez-Canabal
- Cell Biology Department, National Autonomous University of Mexico, Mexico City 04510, Mexico;
| | - Gordon Winocur
- Rotman Research Institute, Baycrest Center, Toronto, ON M6A 2E1, Canada;
- Department of Psychology, Department of Psychiatry, University of Toronto, Toronto, ON M5S 3G3, Canada
- Department of Psychology, Trent University, Peterborough, ON K9J 7B8, Canada
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Martins-Macedo J, Salgado AJ, Gomes ED, Pinto L. Adult brain cytogenesis in the context of mood disorders: From neurogenesis to the emergent role of gliogenesis. Neurosci Biobehav Rev 2021; 131:411-428. [PMID: 34555383 DOI: 10.1016/j.neubiorev.2021.09.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 09/06/2021] [Accepted: 09/16/2021] [Indexed: 12/18/2022]
Abstract
Psychiatric disorders severely impact patients' lives. Motivational, cognitive and emotional deficits are the most common symptoms observed in these patients and no effective treatment is still available, either due to the adverse side effects or the low rate of efficacy of currently available drugs. Neurogenesis recovery has been one important focus in the treatment of psychiatric disorders, which undeniably contributes to the therapeutic action of antidepressants. However, glial plasticity is emerging as a new strategy to explore the deficits observed in mood disorders and the efficacy of therapeutic interventions. Thus, it is crucial to understand the mechanisms behind glio- and neurogenesis to better define treatments and preventive therapies, once adult cytogenesis is of pivotal importance to cognitive and emotional components of behavior, both in healthy and pathological contexts, including in psychiatric disorders. Here, we review the concepts and history of neuro- and gliogenesis, providing as well a reflection on the functional importance of cytogenesis in the context of disease.
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Affiliation(s)
- Joana Martins-Macedo
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - António J Salgado
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Eduardo D Gomes
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Luísa Pinto
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
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Positive Controls in Adults and Children Support That Very Few, If Any, New Neurons Are Born in the Adult Human Hippocampus. J Neurosci 2021; 41:2554-2565. [PMID: 33762407 DOI: 10.1523/jneurosci.0676-20.2020] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 11/06/2020] [Accepted: 11/10/2020] [Indexed: 01/19/2023] Open
Abstract
Adult hippocampal neurogenesis was originally discovered in rodents. Subsequent studies identified the adult neural stem cells and found important links between adult neurogenesis and plasticity, behavior, and disease. However, whether new neurons are produced in the human dentate gyrus (DG) during healthy aging is still debated. We and others readily observe proliferating neural progenitors in the infant hippocampus near immature cells expressing doublecortin (DCX), but the number of such cells decreases in children and few, if any, are present in adults. Recent investigations using dual antigen retrieval find many cells stained by DCX antibodies in adult human DG. This has been interpreted as evidence for high rates of adult neurogenesis, even at older ages. However, most of these DCX-labeled cells have mature morphology. Furthermore, studies in the adult human DG have not found a germinal region containing dividing progenitor cells. In this Dual Perspectives article, we show that dual antigen retrieval is not required for the detection of DCX in multiple human brain regions of infants or adults. We review prior studies and present new data showing that DCX is not uniquely expressed by newly born neurons: DCX is present in adult amygdala, entorhinal and parahippocampal cortex neurons despite being absent in the neighboring DG. Analysis of available RNA-sequencing datasets supports the view that DG neurogenesis is rare or absent in the adult human brain. To resolve the conflicting interpretations in humans, it is necessary to identify and visualize dividing neuronal precursors or develop new methods to evaluate the age of a neuron at the single-cell level.
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Rule L, Yang J, Watkin H, Hall J, Brydges NM. Environmental enrichment rescues survival and function of adult-born neurons following early life stress. Mol Psychiatry 2021; 26:1898-1908. [PMID: 32286496 DOI: 10.1038/s41380-020-0718-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/12/2020] [Accepted: 03/24/2020] [Indexed: 01/06/2023]
Abstract
Adverse experiences early in life are associated with the development of psychiatric illnesses. The hippocampus is likely to play pivotal role in generating these effects: it undergoes significant development during childhood and is extremely reactive to stress. In rodent models, stress in the pre-pubertal period impairs adult hippocampal neurogenesis (AHN) and behaviours which rely on this process. In normal adult animals, environmental enrichment (EE) is a potent promoter of AHN and hippocampal function. Whether exposure to EE during adolescence can restore normal hippocampal function and AHN following pre-pubertal stress (PPS) is unknown. We investigated EE as a treatment for reduced AHN and hippocampal function following PPS in a rodent model. Stress was administered between post-natal days (PND) 25-27, EE from PND 35 to early adulthood, when behavioural testing and assessment of AHN took place. PPS enhanced fear reactions to a conditioned stimulus (CS) following a trace fear protocol and reduced the survival of 4-week-old adult-born neurons throughout the adult hippocampus. Furthermore, we show that fewer adult-born neurons were active during recall of the CS stimulus following PPS. All effects were reversed by EE. Our results demonstrate lasting effects of PPS on the hippocampus and highlight the utility of EE during adolescence for restoring normal hippocampal function. EE during adolescence is a promising method of enhancing impaired hippocampal function resulting from early life stress, and due to multiple benefits (low cost, few side effects, widespread availability) should be more thoroughly explored as a treatment option in human sufferers of childhood adversity.
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Affiliation(s)
- Lowenna Rule
- Neuroscience and Mental Health Research Institute, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Jessica Yang
- Neuroscience and Mental Health Research Institute, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Holly Watkin
- Neuroscience and Mental Health Research Institute, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Jeremy Hall
- Neuroscience and Mental Health Research Institute, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK.,MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK
| | - Nichola Marie Brydges
- Neuroscience and Mental Health Research Institute, Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, CF24 4HQ, UK.
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Babcock KR, Page JS, Fallon JR, Webb AE. Adult Hippocampal Neurogenesis in Aging and Alzheimer's Disease. Stem Cell Reports 2021; 16:681-693. [PMID: 33636114 PMCID: PMC8072031 DOI: 10.1016/j.stemcr.2021.01.019] [Citation(s) in RCA: 109] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/27/2021] [Accepted: 01/27/2021] [Indexed: 12/19/2022] Open
Abstract
Cognitive deficits associated with Alzheimer's disease (AD) severely impact daily life for the millions of affected individuals. Progressive memory impairment in AD patients is associated with degeneration of the hippocampus. The dentate gyrus of the hippocampus, a region critical for learning and memory functions, is a site of adult neurogenesis in mammals. Recent evidence in humans indicates that hippocampal neurogenesis likely persists throughout life, but declines with age and is strikingly impaired in AD. Our understanding of how neurogenesis supports learning and memory in healthy adults is only beginning to emerge. The extent to which decreased neurogenesis contributes to cognitive decline in aging and AD remains poorly understood. However, studies in rodent models of AD and other neurodegenerative diseases raise the possibility that targeting neurogenesis may ameliorate cognitive dysfunction in AD. Here, we review recent progress in understanding how adult neurogenesis is impacted in the context of aging and AD.
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Affiliation(s)
- Kelsey R Babcock
- Graduate Program in Neuroscience, Brown University, Providence, RI 02912, USA
| | - John S Page
- Warren Alpert Medical School of Brown University, Providence, RI 02912, USA; Department of Neuroscience, Brown University, Providence, RI 02912, USA
| | - Justin R Fallon
- Department of Neuroscience, Brown University, Providence, RI 02912, USA; Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA; Center for Translational Neuroscience, Brown University, Providence, RI 02912, USA
| | - Ashley E Webb
- Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA; Center for Translational Neuroscience, Brown University, Providence, RI 02912, USA; Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, USA; Center on the Biology of Aging, Brown University, Providence, RI 02912, USA.
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13
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Mishra P, Narayanan R. Ion-channel regulation of response decorrelation in a heterogeneous multi-scale model of the dentate gyrus. CURRENT RESEARCH IN NEUROBIOLOGY 2021; 2:100007. [PMID: 33997798 PMCID: PMC7610774 DOI: 10.1016/j.crneur.2021.100007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Heterogeneities in biological neural circuits manifest in afferent connectivity as well as in local-circuit components such as neuronal excitability, neural structure and local synaptic strengths. The expression of adult neurogenesis in the dentate gyrus (DG) amplifies local-circuit heterogeneities and guides heterogeneities in afferent connectivity. How do neurons and their networks endowed with these distinct forms of heterogeneities respond to perturbations to individual ion channels, which are known to change under several physiological and pathophysiological conditions? We sequentially traversed the ion channels-neurons-network scales and assessed the impact of eliminating individual ion channels on conductance-based neuronal and network models endowed with disparate local-circuit and afferent heterogeneities. We found that many ion channels differentially contributed to specific neuronal or network measurements, and the elimination of any given ion channel altered several functional measurements. We then quantified the impact of ion-channel elimination on response decorrelation, a well-established metric to assess the ability of neurons in a network to convey complementary information, in DG networks endowed with different forms of heterogeneities. Notably, we found that networks constructed with structurally immature neurons exhibited functional robustness, manifesting as minimal changes in response decorrelation in the face of ion-channel elimination. Importantly, the average change in output correlation was dependent on the eliminated ion channel but invariant to input correlation. Our analyses suggest that neurogenesis-driven structural heterogeneities could assist the DG network in providing functional resilience to molecular perturbations. Perturbations at one scale result in a cascading impact on physiology across scales. Heterogeneous multi-scale models used to assess the impact of ion-channel deletion. Mapping of structural components to functional outcomes is many-to-many. Differential & variable impact of ion channel deletion on response decorrelation. Neurogenesis-induced structural heterogeneity confers resilience to perturbations.
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Affiliation(s)
- Poonam Mishra
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Rishikesh Narayanan
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
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14
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Lybrand ZR, Goswami S, Zhu J, Jarzabek V, Merlock N, Aktar M, Smith C, Zhang L, Varma P, Cho KO, Ge S, Hsieh J. A critical period of neuronal activity results in aberrant neurogenesis rewiring hippocampal circuitry in a mouse model of epilepsy. Nat Commun 2021; 12:1423. [PMID: 33658509 PMCID: PMC7930276 DOI: 10.1038/s41467-021-21649-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 02/04/2021] [Indexed: 01/31/2023] Open
Abstract
In the mammalian hippocampus, adult-born granule cells (abGCs) contribute to the function of the dentate gyrus (DG). Disruption of the DG circuitry causes spontaneous recurrent seizures (SRS), which can lead to epilepsy. Although abGCs contribute to local inhibitory feedback circuitry, whether they are involved in epileptogenesis remains elusive. Here, we identify a critical window of activity associated with the aberrant maturation of abGCs characterized by abnormal dendrite morphology, ectopic migration, and SRS. Importantly, in a mouse model of temporal lobe epilepsy, silencing aberrant abGCs during this critical period reduces abnormal dendrite morphology, cell migration, and SRS. Using mono-synaptic tracers, we show silencing aberrant abGCs decreases recurrent CA3 back-projections and restores proper cortical connections to the hippocampus. Furthermore, we show that GABA-mediated amplification of intracellular calcium regulates the early critical period of activity. Our results demonstrate that aberrant neurogenesis rewires hippocampal circuitry aggravating epilepsy in mice.
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Affiliation(s)
- Zane R Lybrand
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
- Department of Biology, Texas Woman's University, Denton, TX, USA
| | - Sonal Goswami
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Jingfei Zhu
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Veronica Jarzabek
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Nikolas Merlock
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Mahafuza Aktar
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Courtney Smith
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Ling Zhang
- Department of Molecular Biology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Parul Varma
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Kyung-Ok Cho
- Department of Pharmacology, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, South Korea
- Department of Biomedicine & Health Sciences, Institute of Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Shaoyu Ge
- Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Jenny Hsieh
- Department of Biology, The University of Texas at San Antonio, San Antonio, TX, USA.
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, USA.
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15
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Huckleberry KA, Shansky RM. The unique plasticity of hippocampal adult-born neurons: Contributing to a heterogeneous dentate. Hippocampus 2021; 31:543-556. [PMID: 33638581 DOI: 10.1002/hipo.23318] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/15/2021] [Accepted: 02/09/2021] [Indexed: 12/14/2022]
Abstract
The dentate gyrus (DG) of the hippocampus is evolutionarily conserved as one of the few sites of adult neurogenesis in mammals. Although there is clear evidence that neurogenesis is necessary for healthy hippocampal function, whether adult-born neurons are simply integrated into existing hippocampal networks to serve a similar purpose to that of developmentally born neurons or whether they represent a discrete cell population with unique functions remains less clear. In this review, we consider evidence for discrete cellular, synaptic, and structural features of adult-born DG neurons, suggesting that neurogenesis contributes to the formation of a heterogeneous DG. We therefore propose that hippocampal neurogenesis creates a specialized neuronal subpopulation that may play a key role in hippocampal functions like episodic memory. We note critical gaps in this extensive body of work, including a general failure to include female animals in relevant research and a need for more precise consideration of intrahippocampal neuroanatomy.
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Affiliation(s)
- Kylie A Huckleberry
- Behavioral Neuroscience Program, Department of Psychology, Northeastern University, Boston, Massachusetts, USA
| | - Rebecca M Shansky
- Behavioral Neuroscience Program, Department of Psychology, Northeastern University, Boston, Massachusetts, USA
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16
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Trova S, Bovetti S, Pellegrino G, Bonzano S, Giacobini P, Peretto P. HPG-Dependent Peri-Pubertal Regulation of Adult Neurogenesis in Mice. Front Neuroanat 2020; 14:584493. [PMID: 33328903 PMCID: PMC7732626 DOI: 10.3389/fnana.2020.584493] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 10/29/2020] [Indexed: 11/13/2022] Open
Abstract
Adult neurogenesis, a striking form of neural plasticity, is involved in the modulation of social stimuli driving reproduction. Previous studies on adult neurogenesis have shown that this process is significantly modulated around puberty in female mice. Puberty is a critical developmental period triggered by increased secretion of the gonadotropin releasing hormone (GnRH), which controls the activity of the hypothalamic-pituitary-gonadal axis (HPG). Secretion of HPG-axis factors at puberty participates to the refinement of neural circuits that govern reproduction. Here, by exploiting a transgenic GnRH deficient mouse model, that progressively loses GnRH expression during postnatal development (GnRH::Cre;Dicer loxP/loxP mice), we found that a postnatally-acquired dysfunction in the GnRH system affects adult neurogenesis selectively in the subventricular-zone neurogenic niche in a sexually dimorphic way. Moreover, by examining adult females ovariectomized before the onset of puberty, we provide important evidence that, among the HPG-axis secreting factors, the circulating levels of gonadal hormones during pre-/peri-pubertal life contribute to set-up the proper adult subventricular zone-olfactory bulb neurogenic system.
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Affiliation(s)
- Sara Trova
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy.,Univ.Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience and Cognition, Laboratory of the Development and Plasticity of Neuroendocrine Brain, Lille, France
| | - Serena Bovetti
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy
| | - Giuliana Pellegrino
- Univ.Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience and Cognition, Laboratory of the Development and Plasticity of Neuroendocrine Brain, Lille, France
| | - Sara Bonzano
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy
| | - Paolo Giacobini
- Univ.Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience and Cognition, Laboratory of the Development and Plasticity of Neuroendocrine Brain, Lille, France
| | - Paolo Peretto
- Department of Life Sciences and Systems Biology, Neuroscience Institute Cavalieri Ottolenghi, University of Torino, Orbassano, Italy
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17
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Jurkowski MP, Bettio L, K Woo E, Patten A, Yau SY, Gil-Mohapel J. Beyond the Hippocampus and the SVZ: Adult Neurogenesis Throughout the Brain. Front Cell Neurosci 2020; 14:576444. [PMID: 33132848 PMCID: PMC7550688 DOI: 10.3389/fncel.2020.576444] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 08/19/2020] [Indexed: 12/31/2022] Open
Abstract
Convincing evidence has repeatedly shown that new neurons are produced in the mammalian brain into adulthood. Adult neurogenesis has been best described in the hippocampus and the subventricular zone (SVZ), in which a series of distinct stages of neuronal development has been well characterized. However, more recently, new neurons have also been found in other brain regions of the adult mammalian brain, including the hypothalamus, striatum, substantia nigra, cortex, and amygdala. While some studies have suggested that these new neurons originate from endogenous stem cell pools located within these brain regions, others have shown the migration of neurons from the SVZ to these regions. Notably, it has been shown that the generation of new neurons in these brain regions is impacted by neurologic processes such as stroke/ischemia and neurodegenerative disorders. Furthermore, numerous factors such as neurotrophic support, pharmacologic interventions, environmental exposures, and stem cell therapy can modulate this endogenous process. While the presence and significance of adult neurogenesis in the human brain (and particularly outside of the classical neurogenic regions) is still an area of debate, this intrinsic neurogenic potential and its possible regulation through therapeutic measures present an exciting alternative for the treatment of several neurologic conditions. This review summarizes evidence in support of the classic and novel neurogenic zones present within the mammalian brain and discusses the functional significance of these new neurons as well as the factors that regulate their production. Finally, it also discusses the potential clinical applications of promoting neurogenesis outside of the classical neurogenic niches, particularly in the hypothalamus, cortex, striatum, substantia nigra, and amygdala.
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Affiliation(s)
- Michal P Jurkowski
- Island Medical Program, University of British Columbia, Vancouver, BC, Canada
| | - Luis Bettio
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Emma K Woo
- Island Medical Program, University of British Columbia, Vancouver, BC, Canada
| | - Anna Patten
- Centre for Interprofessional Clinical Simulation Learning (CICSL), Royal Jubilee Hospital, Victoria, BC, Canada
| | - Suk-Yu Yau
- Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Joana Gil-Mohapel
- Island Medical Program, University of British Columbia, Vancouver, BC, Canada.,Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
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18
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Zhang X, Schlögl A, Jonas P. Selective Routing of Spatial Information Flow from Input to Output in Hippocampal Granule Cells. Neuron 2020; 107:1212-1225.e7. [PMID: 32763145 PMCID: PMC7523402 DOI: 10.1016/j.neuron.2020.07.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/22/2020] [Accepted: 07/10/2020] [Indexed: 11/18/2022]
Abstract
Dentate gyrus granule cells (GCs) connect the entorhinal cortex to the hippocampal CA3 region, but how they process spatial information remains enigmatic. To examine the role of GCs in spatial coding, we measured excitatory postsynaptic potentials (EPSPs) and action potentials (APs) in head-fixed mice running on a linear belt. Intracellular recording from morphologically identified GCs revealed that most cells were active, but activity level varied over a wide range. Whereas only ∼5% of GCs showed spatially tuned spiking, ∼50% received spatially tuned input. Thus, the GC population broadly encodes spatial information, but only a subset relays this information to the CA3 network. Fourier analysis indicated that GCs received conjunctive place-grid-like synaptic input, suggesting code conversion in single neurons. GC firing was correlated with dendritic complexity and intrinsic excitability, but not extrinsic excitatory input or dendritic cable properties. Thus, functional maturation may control input-output transformation and spatial code conversion.
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Affiliation(s)
- Xiaomin Zhang
- Cellular Neuroscience, IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Alois Schlögl
- Cellular Neuroscience, IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Peter Jonas
- Cellular Neuroscience, IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria.
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19
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Calsequestrin Deletion Facilitates Hippocampal Synaptic Plasticity and Spatial Learning in Post-Natal Development. Int J Mol Sci 2020; 21:ijms21155473. [PMID: 32751833 PMCID: PMC7432722 DOI: 10.3390/ijms21155473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/15/2020] [Accepted: 07/30/2020] [Indexed: 11/17/2022] Open
Abstract
Experimental evidence highlights the involvement of the endoplasmic reticulum (ER)-mediated Ca2+ signals in modulating synaptic plasticity and spatial memory formation in the hippocampus. Ca2+ release from the ER mainly occurs through two classes of Ca2+ channels, inositol 1,4,5-trisphosphate receptors (InsP3Rs) and ryanodine receptors (RyRs). Calsequestrin (CASQ) and calreticulin (CR) are the most abundant Ca2+-binding proteins allowing ER Ca2+ storage. The hippocampus is one of the brain regions expressing CASQ, but its role in neuronal activity, plasticity, and the learning processes is poorly investigated. Here, we used knockout mice lacking both CASQ type-1 and type-2 isoforms (double (d)CASQ-null mice) to: a) evaluate in adulthood the neuronal electrophysiological properties and synaptic plasticity in the hippocampal Cornu Ammonis 1 (CA1) field and b) study the performance of knockout mice in spatial learning tasks. The ablation of CASQ increased the CA1 neuron excitability and improved the long-term potentiation (LTP) maintenance. Consistently, (d)CASQ-null mice performed significantly better than controls in the Morris Water Maze task, needing a shorter time to develop a spatial preference for the goal. The Ca2+ handling analysis in CA1 pyramidal cells showed a decrement of Ca2+ transient amplitude in (d)CASQ-null mouse neurons, which is consistent with a decrease in afterhyperpolarization improving LTP. Altogether, our findings suggest that CASQ deletion affects activity-dependent ER Ca2+ release, thus facilitating synaptic plasticity and spatial learning in post-natal development.
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20
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Di Palma M, Sartini S, Lattanzi D, Cuppini R, Pita-Rodriguez M, Diaz-Carmenate Y, Narvaez M, Fuxe K, Borroto-Escuela DO, Ambrogini P. Evidence for the existence of A2AR-TrkB heteroreceptor complexes in the dorsal hippocampus of the rat brain: Potential implications of A2AR and TrkB interplay upon ageing. Mech Ageing Dev 2020; 190:111289. [PMID: 32565059 DOI: 10.1016/j.mad.2020.111289] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 06/14/2020] [Accepted: 06/16/2020] [Indexed: 10/24/2022]
Abstract
Adenosine A2A receptors (A2AR) are crucial in facilitating the BDNF action on synaptic transmission in the rat hippocampus primarily upon ageing. Furthermore, it has been suggested that A2AR-Tropomyosin related kinase B receptor (TrkB) crosstalk has a pivotal role in adenosine A2AR-mediated modulation of the BDNF action on hippocampal plasticity. Considering the impact of the above receptors interplay on what concerns BDNF-induced enhancement of synaptic transmission, gaining a better insight into the mechanisms behind this powerful crosstalk becomes of primary interest. Using in situ proximity ligation assay (PLA), the existence of a direct physical interaction between adenosine A2AR and TrkB is demonstrated. The A2AR-TrkB heteroreceptor complexes show a heterogeneous distribution within the rat dorsal hippocampus. High densities of the heteroreceptor complexes were observed in the pyramidal cell layers of CA1-CA3 regions and in the polymorphic layer of the dentate gyrus (DG). The stratum radiatum of the CA1-3 regions showed positive PLA signal in contrast to the oriens region. The molecular and granular layers of the DG also lacked significant densities of PLA positive heteroreceptor complexes, but subgranular zone showed some PLA positive cells. Their allosteric receptor-receptor interactions may significantly modulate BDNF signaling impacting on hippocampal plasticity which is impaired upon ageing.
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Affiliation(s)
- Michael Di Palma
- Department of Experimental and Clinical Medicine, Faculty of Medicine and Surgery, Università Politecnica Delle Marche, Ancona, Italy.
| | - Stefano Sartini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Davide Lattanzi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Riccardo Cuppini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Mariana Pita-Rodriguez
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Málaga, Spain; Departamento de Diagnóstico Molecular, Centro de Neurociencias de Cuba, La Habana, Cuba
| | | | - Manuel Narvaez
- Universidad de Málaga, Instituto de Investigación Biomédica de Málaga, Málaga, Spain
| | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Dasiel O Borroto-Escuela
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Patrizia Ambrogini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
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21
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Moutin E, Hemonnot AL, Seube V, Linck N, Rassendren F, Perroy J, Compan V. Procedures for Culturing and Genetically Manipulating Murine Hippocampal Postnatal Neurons. Front Synaptic Neurosci 2020; 12:19. [PMID: 32425766 PMCID: PMC7204911 DOI: 10.3389/fnsyn.2020.00019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 04/03/2020] [Indexed: 12/15/2022] Open
Abstract
Neuronal hippocampal cultures are simple and valuable models for studying neuronal function. While embryonic cultures are widely used for different applications, mouse postnatal cultures are still challenging, lack reproducibility and/or exhibit inappropriate neuronal activity. Yet, postnatal cultures have major advantages such as allowing genotyping of pups before culture and reducing the number of experimental animals. Herein we describe a simple and fast protocol for culturing and genetically manipulating hippocampal neurons from P0 to P3 mice. This protocol provides reproducible cultures exhibiting a consistent neuronal development, normal excitatory over inhibitory neuronal ratio and a physiological neuronal activity. We also describe simple and efficient procedures for genetic manipulation of neurons using transfection reagent or lentiviral particles. Overall, this method provides a detailed and validated protocol allowing to explore cellular mechanisms and neuronal activity in postnatal hippocampal neurons in culture.
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Affiliation(s)
- Enora Moutin
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Anne-Laure Hemonnot
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France.,Laboratoire d'Excellence Canaux Ioniques d'Intérêt Thérapeutique (LabEx ICST), Montpellier, France
| | - Vincent Seube
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France.,Laboratoire d'Excellence Canaux Ioniques d'Intérêt Thérapeutique (LabEx ICST), Montpellier, France
| | - Nathalie Linck
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France.,Laboratoire d'Excellence Canaux Ioniques d'Intérêt Thérapeutique (LabEx ICST), Montpellier, France
| | - François Rassendren
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France.,Laboratoire d'Excellence Canaux Ioniques d'Intérêt Thérapeutique (LabEx ICST), Montpellier, France
| | - Julie Perroy
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Vincent Compan
- Institut de Génomique Fonctionnelle (IGF), University of Montpellier, CNRS, INSERM, Montpellier, France.,Laboratoire d'Excellence Canaux Ioniques d'Intérêt Thérapeutique (LabEx ICST), Montpellier, France
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22
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Jaimes LF, Mansk LMZ, Almeida-Santos AF, Pereira GS. Maturation of newborn neurons predicts social memory persistence in mice. Neuropharmacology 2020; 171:108102. [PMID: 32302616 DOI: 10.1016/j.neuropharm.2020.108102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 04/01/2020] [Accepted: 04/06/2020] [Indexed: 10/24/2022]
Abstract
Memory transience is essential to gain cognitive flexibility. Recently, hippocampal neurogenesis is emerging as one of the mechanisms involved in the balance between persistence and forgetting. Social recognition memory (SRM) has its duration prolonged by neurogenesis. However, it is still to be determined whether boosting neurogenesis in distinct phases of SRM may favor forgetting over persistence. In the present study, we used enriched environment (EE) and memantine (MEM) to increase neurogenesis. SRM was ubiquitously prolonged by both, while EE after the memory acquisition did not favor forgetting. Interestingly, the proportion of newborn neurons with mature morphology in the dorsal hippocampus was higher in animals where persistence prevailed. Finally, one of the main factors for dendritic growth is the formation of cytoskeleton. We found that Latrunculin A, an inhibitor of actin polymerization, blunted the promnesic effect of EE. Altogether, our results indicate that the mechanisms triggered by EE to improve SRM are not limited to increasing the number of newborn neurons.
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Affiliation(s)
- Laura F Jaimes
- Núcleo de Neurociências, Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas, Gerais, Brazil
| | - Lara M Z Mansk
- Núcleo de Neurociências, Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas, Gerais, Brazil
| | - Ana F Almeida-Santos
- Núcleo de Neurociências, Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas, Gerais, Brazil
| | - Grace S Pereira
- Núcleo de Neurociências, Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas, Gerais, Brazil.
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23
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Pushchina EV, Zharikova EI, Varaksin AA, Prudnikov IM, Tsyvkin VN. Proliferation, Adult Neuronal Stem Cells and Cells Migration in Pallium during Constitutive Neurogenesis and after Traumatic Injury of Telencephalon of Juvenile Masu Salmon, Oncorhynchus masou. Brain Sci 2020; 10:brainsci10040222. [PMID: 32276413 PMCID: PMC7226367 DOI: 10.3390/brainsci10040222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/31/2020] [Accepted: 04/06/2020] [Indexed: 12/11/2022] Open
Abstract
A study of the lateral pallium in zebrafish and the visual tectum of the medaka revealed a population of adult neuroepithelial (NE) cells supported from the early stage of development to various postembryonic stages of ontogenesis. These data emphasize the importance of non-radial glial stem cells in the neurogenesis of adult animals, in particular fish. However, the distribution, cell cycle features, and molecular markers of NE cells and glial progenitors in fish are still poorly understood at the postembryonic stages of ontogenesis. Fetalization predominates in the ontogenetic development of salmon fish, which is associated with a delay in development and preservation of the features of the embryonic structure of the brain during the first year of life. In the present work, we studied the features of proliferation and the migration of neuronal precursors in the pallial proliferative zone of juvenile Oncorhynchus masou. The aim of the study is a comparative analysis of the distribution of glial-type aNSCs markers, such as vimentin and glial fibrillar acid protein GFAP, as well as the proliferation marker BrdU and migratory neuronal precursor doublecortin, in the pallial zone of the intact telencephalon in juvenile O. masou normal and after mechanical injury. The immunohistochemical IHC labeling with antibodies to vimentin, GFAP and doublecortin in the pallium of intact fish revealed single, small, round and oval immunopositive cells, that correspond to a persistent pool of neuronal and/or glial progenitors. After the injury, heterogeneous cell clusters, radial glia processes, single and small intensely labeled GFAP+ cells in the parenchyma of Dd and lateral part of pallium (Dl) appeared, corresponding to reactive neurogenic niches containing glial aNSCs. A multifold increase in the pool of Vim+ neuronal precursor cells (NPCs) resulting from the injury was observed. Vim+ cells of the neuroepithelial type in Dd and Dm and cells of the glial type were identified in Dl after the injury. Doublecortine (Dc) immunolabeling after the injury revealed the radial migration of neuroblasts into Dm from the neurogenic zone of the pallium. The appearance of intensely labeled Dc+ cells in the brain parenchyma might indicate the activation of resident aNSCs as a consequence of the traumatic process.
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Affiliation(s)
- Evgeniya V. Pushchina
- Zhirmunsky National Scientific Center of Marine Biology, Far East Branch, Russian Academy of Sciences, 690041 Vladivostok, Russia; (E.I.Z.); (A.A.V.)
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 01024 Kyiv, Ukraine; (I.M.P.); (V.N.T.)
- Correspondence: ; Tel.: +79-149680177
| | - Eva I. Zharikova
- Zhirmunsky National Scientific Center of Marine Biology, Far East Branch, Russian Academy of Sciences, 690041 Vladivostok, Russia; (E.I.Z.); (A.A.V.)
| | - Anatoly A. Varaksin
- Zhirmunsky National Scientific Center of Marine Biology, Far East Branch, Russian Academy of Sciences, 690041 Vladivostok, Russia; (E.I.Z.); (A.A.V.)
| | - Igor M. Prudnikov
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 01024 Kyiv, Ukraine; (I.M.P.); (V.N.T.)
| | - Vladimir N. Tsyvkin
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 01024 Kyiv, Ukraine; (I.M.P.); (V.N.T.)
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Lattanzi D, Di Palma M, Cuppini R, Ambrogini P. GABAergic Input Affects Intracellular Calcium Levels in Developing Granule Cells of Adult Rat Hippocampus. Int J Mol Sci 2020; 21:ijms21051715. [PMID: 32138257 PMCID: PMC7084234 DOI: 10.3390/ijms21051715] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 03/02/2020] [Indexed: 12/20/2022] Open
Abstract
In the dentate gyrus (DG) of the mammalian hippocampus, granule neurons are generated from neural stem cells (NSCs) throughout the life span and are integrated into the hippocampal network. Adult DG neurogenesis is regulated by multiple intrinsic and extrinsic factors that control NSC proliferation, maintenance, and differentiation into mature neurons. γ-Aminobutyric acid (GABA), released by local interneurons, regulates the development of neurons born in adulthood by activating extrasynaptic and synaptic GABAA receptors. In the present work, patch-clamp and calcium imaging techniques were used to record very immature granule cells of adult rat dentate gyrus for investigating the actual role of GABAA receptor activation in intracellular calcium level regulation at an early stage of maturation. Our findings highlight a novel molecular and electrophysiological mechanism, involving calcium-activated potassium channels (BK) and T-type voltage-dependent calcium channels, through which GABA fine-tunes intracellular calcium homeostasis in rat adult-born granule neurons early during their maturation. This mechanism might be instrumental in promoting newborn cell survival.
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Pushchina EV, Kapustyanov IA, Varaksin AA. Neural Stem Cells/Neuronal Precursor Cells and Postmitotic Neuroblasts in Constitutive Neurogenesis and After ,Traumatic Injury to the Mesencephalic Tegmentum of Juvenile Chum Salmon, Oncorhynchus keta. Brain Sci 2020; 10:brainsci10020065. [PMID: 31991815 PMCID: PMC7071460 DOI: 10.3390/brainsci10020065] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/15/2020] [Accepted: 01/22/2020] [Indexed: 11/30/2022] Open
Abstract
The proliferation of neural stem cells (NSCs)/neuronal precursor cells (NPCs) and the occurrence of postmitotic neuroblasts in the mesencephalic tegmentum of intact juvenile chum salmon, Oncorhynchus keta, and at 3 days after a tegmental injury, were studied by immunohistochemical labeling. BrdU+ constitutive progenitor cells located both in the periventricular matrix zone and in deeper subventricular and parenchymal layers of the brain are revealed in the tegmentum of juvenile chum salmon. As a result of traumatic damage to the tegmentum, the proliferation of resident progenitor cells of the neuroepithelial type increases. Nestin-positive and vimentin-positive NPCs and granules located in the periventricular and subventricular matrix zones, as well as in the parenchymal regions of the tegmentum, are revealed in the mesencephalic tegmentum of juvenile chum salmon, which indicates a high level of constructive metabolism and constitutive neurogenesis. The expression of vimentin and nestin in the extracellular space, as well as additionally in the NSCs and NPCs of the neuroepithelial phenotype, which do not express nestin in the control animals, is enhanced during the traumatic process. As a result of the proliferation of such cells in the post-traumatic period, local Nes+ and Vim+ NPCs clusters are formed and become involved in the reparative response. Along with the primary traumatic lesion, which coincides with the injury zone, additional Nes+ and Vim+ secondary lesions are observed to form in the adjacent subventricular and parenchymal zones of the tegmentum. In the lateral tegmentum, the number of doublecortin-positive cells is higher compared to that in the medial tegmentum, which determines the different intensities and rates of neuronal differentiation in the sensory and motor regions of the tegmentum, respectively. In periventricular regions remote from the injury, the expression of doublecortin in single cells and their groups significantly increases compared to that in the damage zone.
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Affiliation(s)
- Evgeniya V. Pushchina
- Zhirmunsky National Scientific Center of Marine Biology, Far East Branch, Russian Academy of Sciences, Vladivostok 690041, Russia; (I.A.K.); (A.A.V.)
- Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv 01024, Ukraine
- Correspondence:
| | - Ilya A. Kapustyanov
- Zhirmunsky National Scientific Center of Marine Biology, Far East Branch, Russian Academy of Sciences, Vladivostok 690041, Russia; (I.A.K.); (A.A.V.)
| | - Anatoly A. Varaksin
- Zhirmunsky National Scientific Center of Marine Biology, Far East Branch, Russian Academy of Sciences, Vladivostok 690041, Russia; (I.A.K.); (A.A.V.)
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Sartini S, Lattanzi D, Di Palma M, Savelli D, Eusebi S, Sestili P, Cuppini R, Ambrogini P. Maternal Creatine Supplementation Positively Affects Male Rat Hippocampal Synaptic Plasticity in Adult Offspring. Nutrients 2019; 11:nu11092014. [PMID: 31461895 PMCID: PMC6770830 DOI: 10.3390/nu11092014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 08/16/2019] [Accepted: 08/23/2019] [Indexed: 01/16/2023] Open
Abstract
Creatine plays a crucial role in developing the brain, so much that its genetic deficiency results in mental dysfunction and cognitive impairments. Moreover, creatine supplementation is currently under investigation as a preventive measure to protect the fetus against oxidative stress during difficult pregnancies. Although creatine use is considered safe, posing minimal risk to clinical health, we found an alteration in morpho-functional maturation of neurons when male rats were exposed to creatine loads during brain development. In particular, increased excitability and enhanced long-term potentiation (LTP) were observed in the hippocampal pyramidal neurons of weaning pups. Since these effects were observed a long time after creatine treatment had been terminated, long-lasting modifications persisting into adulthood were hypothesized. Such modifications were investigated in the present study using morphological, electrophysiological, and calcium imaging techniques applied to hippocampal Cornu Ammonis 1 (CA1) neurons of adult rats born from dams supplemented with creatine. When compared to age-matched controls, the treated adult offspring were found to retain enhanced neuron excitability and an improved LTP, the best-documented neuronal substrate for memory formation. While translating data from rats to humans does have limitations, our findings suggest that prenatal creatine supplementation could have positive effects on adult cognitive abilities.
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Affiliation(s)
- Stefano Sartini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, I-61029 Urbino, Italy.
| | - Davide Lattanzi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, I-61029 Urbino, Italy
| | - Michael Di Palma
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, I-61029 Urbino, Italy
| | - David Savelli
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, I-61029 Urbino, Italy
| | - Silvia Eusebi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, I-61029 Urbino, Italy
| | - Piero Sestili
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, I-61029 Urbino, Italy
| | - Riccardo Cuppini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, I-61029 Urbino, Italy
| | - Patrizia Ambrogini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, I-61029 Urbino, Italy
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Jain S, LaFrancois JJ, Botterill JJ, Alcantara-Gonzalez D, Scharfman HE. Adult neurogenesis in the mouse dentate gyrus protects the hippocampus from neuronal injury following severe seizures. Hippocampus 2019; 29:683-709. [PMID: 30672046 PMCID: PMC6640126 DOI: 10.1002/hipo.23062] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/29/2018] [Accepted: 11/30/2018] [Indexed: 01/20/2023]
Abstract
Previous studies suggest that reducing the numbers of adult-born neurons in the dentate gyrus (DG) of the mouse increases susceptibility to severe continuous seizures (status epilepticus; SE) evoked by systemic injection of the convulsant kainic acid (KA). However, it was not clear if the results would be the same for other ways to induce seizures, or if SE-induced damage would be affected. Therefore, we used pilocarpine, which induces seizures by a different mechanism than KA. Also, we quantified hippocampal damage after SE. In addition, we used both loss-of-function and gain-of-function methods in adult mice. We hypothesized that after loss-of-function, mice would be more susceptible to pilocarpine-induced SE and SE-associated hippocampal damage, and after gain-of-function, mice would be more protected from SE and hippocampal damage after SE. For loss-of-function, adult neurogenesis was suppressed by pharmacogenetic deletion of dividing radial glial precursors. For gain-of-function, adult neurogenesis was increased by conditional deletion of pro-apoptotic gene Bax in Nestin-expressing progenitors. Fluoro-Jade C (FJ-C) was used to quantify neuronal injury and video-electroencephalography (video-EEG) was used to quantify SE. Pilocarpine-induced SE was longer in mice with reduced adult neurogenesis, SE had more power and neuronal damage was greater. Conversely, mice with increased adult-born neurons had shorter SE, SE had less power, and there was less neuronal damage. The results suggest that adult-born neurons exert protective effects against SE and SE-induced neuronal injury.
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Affiliation(s)
- Swati Jain
- Center for Dementia Research, The Nathan Kline Institute of Psychiatric Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
| | - John J. LaFrancois
- Center for Dementia Research, The Nathan Kline Institute of Psychiatric Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
| | - Justin J. Botterill
- Center for Dementia Research, The Nathan Kline Institute of Psychiatric Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
| | - David Alcantara-Gonzalez
- Center for Dementia Research, The Nathan Kline Institute of Psychiatric Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
| | - Helen E. Scharfman
- Center for Dementia Research, The Nathan Kline Institute of Psychiatric Research, 140 Old Orangeburg Rd., Orangeburg, NY 10962, USA
- Departments of Child & Adolescent Psychiatry, Neuroscience & Physiology, and Psychiatry, New York Langone Medical Center, New York, NY 10016, USA
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28
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Dentate gyrus neurogenesis across different ages in male rats: an immunohistochemical approach. Biologia (Bratisl) 2019. [DOI: 10.2478/s11756-019-00246-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Synaptic properties of newly generated granule cells support sparse coding in the adult hippocampus. Behav Brain Res 2019; 372:112036. [PMID: 31201871 DOI: 10.1016/j.bbr.2019.112036] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/06/2019] [Accepted: 06/11/2019] [Indexed: 12/14/2022]
Abstract
In the adult hippocampus new neurons are continuously generated throughout life and integrate into the existing network via the formation of thousands of new synapses. Adult-born granule cells are known to improve learning and memory at about 3-6 weeks post mitosis by enhancing the brains ability to discriminate similar memory items. However, the underlying mechanisms are still controversial. Here we review the distinct functional properties of the newborn young neurons, including enhanced excitability, reduced GABAergic inhibition, NMDA-receptor dependent electrogenesis and enhanced synaptic plasticity. Although these cellular properties provide a competitive advantage for synapse formation, they do not generate 'hyperactivity' of young neurons. By contrast, in vivo evidence from immediate early gene expression and calcium imaging indicates that young neurons show sparse activity during learning. Similarly, in vitro data show a low number of high-impact synapses, leading to activation young cells by distinct subsets of afferent fibers with minimal overlap. Overall, the enhanced excitability of young cells does not generate hyperactivity but rather counterbalance the low number of excitatory input synapses. Finally, sparse coding in young neurons has been shown to be crucial for neurogenesis-dependent improvement of learning behavior. Taken together, converging evidence from cell physiology and behavioral studies suggests a mechanism that can explain the beneficial effects of adult neurogenesis on brain function.
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Micheli L, Ceccarelli M, D'Andrea G, Costanzi M, Giacovazzo G, Coccurello R, Caruso C, Tirone F. Fluoxetine or Sox2 reactivate proliferation-defective stem and progenitor cells of the adult and aged dentate gyrus. Neuropharmacology 2018; 141:316-330. [PMID: 30142401 DOI: 10.1016/j.neuropharm.2018.08.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 08/06/2018] [Accepted: 08/20/2018] [Indexed: 01/19/2023]
Abstract
The dentate gyrus of the hippocampus and the subventricular zone are neurogenic niches where the production of new neurons from glia-like stem cells continues throughout adult life. It is not clear whether the pool of stem cells is fated to be exhausted or is conserved until old age. We observed that the antiproliferative gene Btg1 maintains the quiescence of stem cells, and its ablation causes an increase of stem/progenitor cells proliferation in neonatal mice followed by progressive loss of proliferation during adulthood. Fluoxetine is an antidepressant, which exerts a powerful neurogenic effect on dentate gyrus progenitor cells, but is ineffective on stem cells. Here we show that adult dentate gyrus stem cells in the Btg1 knockout mice, with reduced self-renewal and proliferative capability, can be reactivated by fluoxetine, which increases their number greatly above the level of control or fluoxetine-treated wild-type mice. The increase of mitotic index above wild-type in Btg1 knockout fluoxetine-treated stem cells indicates that fluoxetine forces quiescent stem cells to enter the cycle. Stem cell proliferation undergoes continuous reactivation until fluoxetine is administered. Remarkably, fluoxetine reactivates proliferation-defective stem cells also in aged Btg1 knockout mice (15-month-old), an effect absent in wild-type aged mice. Moreover, overexpression of Sox2 retrovirally transduced in Btg1 knockout dentate gyrus cells significantly increases the number of neuroblasts, indicating that Sox2 is able to promote the self-renewal of proliferation-defective stem cells. Overall, the deletion of an antiproliferative gene, such as Btg1, reveals that dentate gyrus stem cells retain a hidden plasticity for self-renewal also in old age, in agreement with a model of permanent self-renewal.
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Affiliation(s)
- Laura Micheli
- Institute of Cell Biology and Neurobiology, National Research Council, Fondazione S.Lucia, Via Del Fosso di Fiorano 64, 00143, Rome, Italy.
| | - Manuela Ceccarelli
- Institute of Cell Biology and Neurobiology, National Research Council, Fondazione S.Lucia, Via Del Fosso di Fiorano 64, 00143, Rome, Italy.
| | - Giorgio D'Andrea
- Institute of Cell Biology and Neurobiology, National Research Council, Fondazione S.Lucia, Via Del Fosso di Fiorano 64, 00143, Rome, Italy; Department of Ecological and Biological Sciences, University of Tuscia, Largo Dell'Università S.n.c., 01100, Viterbo, Italy.
| | - Marco Costanzi
- Department of Human Sciences, LUMSA University, Piazza Delle Vaschette 101, 00193, Rome, Italy.
| | - Giacomo Giacovazzo
- Institute of Cell Biology and Neurobiology, National Research Council, Fondazione S.Lucia, Via Del Fosso di Fiorano 64, 00143, Rome, Italy.
| | - Roberto Coccurello
- Institute of Cell Biology and Neurobiology, National Research Council, Fondazione S.Lucia, Via Del Fosso di Fiorano 64, 00143, Rome, Italy.
| | - Carla Caruso
- Department of Ecological and Biological Sciences, University of Tuscia, Largo Dell'Università S.n.c., 01100, Viterbo, Italy.
| | - Felice Tirone
- Institute of Cell Biology and Neurobiology, National Research Council, Fondazione S.Lucia, Via Del Fosso di Fiorano 64, 00143, Rome, Italy.
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Preferential Targeting of Lateral Entorhinal Inputs onto Newly Integrated Granule Cells. J Neurosci 2018; 38:5843-5853. [PMID: 29793975 DOI: 10.1523/jneurosci.1737-17.2018] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 04/26/2018] [Accepted: 05/17/2018] [Indexed: 12/20/2022] Open
Abstract
Mature dentate granule cells in the hippocampus receive input from the entorhinal cortex via the perforant path in precisely arranged lamina, with medial entorhinal axons innervating the middle molecular layer and lateral entorhinal cortex axons innervating the outer molecular layer. Although vastly outnumbered by mature granule cells, adult-generated newborn granule cells play a unique role in hippocampal function, which has largely been attributed to their enhanced excitability and plasticity (Schmidt-Hieber et al., 2004; Ge et al., 2007). Inputs from the medial and lateral entorhinal cortex carry different informational content. Thus, the distribution of inputs onto newly integrated granule cells will affect their function in the circuit. Using retroviral labeling in combination with selective optogenetic activation of medial or lateral entorhinal inputs, we examined the functional innervation and synaptic maturation of newly generated dentate granule cells in the mouse hippocampus. Our results indicate that lateral entorhinal inputs provide the majority of functional innervation of newly integrated granule cells at 21 d postmitosis. Despite preferential functional targeting, the dendritic spine density of immature granule cells was similar in the outer and middle molecular layers, which we speculate could reflect an unequal distribution of shaft synapses. However, chronic blockade of neurotransmitter release of medial entorhinal axons with tetanus toxin disrupted normal synapse development of both medial and lateral entorhinal inputs. Our results support a role for preferential lateral perforant path input onto newly generated neurons in mediating pattern separation, but also indicate that medial perforant path input is necessary for normal synaptic development.SIGNIFICANCE STATEMENT The formation of episodic memories involves the integration of contextual and spatial information. Newly integrated neurons in the dentate gyrus of the hippocampus play a critical role in this process, despite constituting only a minor fraction of the total number of granule cells. Here we demonstrate that these neurons preferentially receive information thought to convey the context of an experience. Each newly integrated granule cell plays this unique role for ∼1 month before reaching maturity.
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Ambrogini P, Albertini MC, Betti M, Galati C, Lattanzi D, Savelli D, Di Palma M, Saccomanno S, Bartolini D, Torquato P, Ruffolo G, Olivieri F, Galli F, Palma E, Minelli A, Cuppini R. Neurobiological Correlates of Alpha-Tocopherol Antiepileptogenic Effects and MicroRNA Expression Modulation in a Rat Model of Kainate-Induced Seizures. Mol Neurobiol 2018; 55:7822-7838. [PMID: 29468563 PMCID: PMC6132771 DOI: 10.1007/s12035-018-0946-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/31/2018] [Indexed: 12/19/2022]
Abstract
Seizure-triggered maladaptive neural plasticity and neuroinflammation occur during the latent period as a key underlying event in epilepsy chronicization. Previously, we showed that α-tocopherol (α-T) reduces hippocampal neuroglial activation and neurodegeneration in the rat model of kainic acid (KA)-induced status epilepticus (SE). These findings allowed us to postulate an antiepileptogenic potential for α-T in hippocampal excitotoxicity, in line with clinical evidence showing that α-T improves seizure control in drug-resistant patients. To explore neurobiological correlates of the α-T antiepileptogenic role, rats were injected with such vitamin during the latent period starting right after KA-induced SE, and the effects on circuitry excitability, neuroinflammation, neuronal death, and microRNA (miRNA) expression were investigated in the hippocampus. Results show that in α-T-treated epileptic rats, (1) the number of population spikes elicited by pyramidal neurons, as well as the latency to the onset of epileptiform-like network activity recover to control levels; (2) neuronal death is almost prevented; (3) down-regulation of claudin, a blood-brain barrier protein, is fully reversed; (4) neuroinflammation processes are quenched (as indicated by the decrease of TNF-α, IL-1β, GFAP, IBA-1, and increase of IL-6); (5) miR-146a, miR-124, and miR-126 expression is coherently modulated in hippocampus and serum by α-T. These findings support the potential of a timely intervention with α-T in clinical management of SE to reduce epileptogenesis, thus preventing chronic epilepsy development. In addition, we suggest that the analysis of miRNA levels in serum could provide clinicians with a tool to evaluate disease evolution and the efficacy of α-T therapy in SE.
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Affiliation(s)
- Patrizia Ambrogini
- Department of Biomolecular Sciences, Section of Physiology, University of Urbino Carlo Bo, I-61029, Urbino, Italy.
| | - Maria Cristina Albertini
- Department of Biomolecular Sciences, Section of Physiology, University of Urbino Carlo Bo, I-61029, Urbino, Italy
| | - Michele Betti
- Department of Biomolecular Sciences, Section of Physiology, University of Urbino Carlo Bo, I-61029, Urbino, Italy
| | - Claudia Galati
- Department of Biomolecular Sciences, Section of Physiology, University of Urbino Carlo Bo, I-61029, Urbino, Italy
| | - Davide Lattanzi
- Department of Biomolecular Sciences, Section of Physiology, University of Urbino Carlo Bo, I-61029, Urbino, Italy
| | - David Savelli
- Department of Biomolecular Sciences, Section of Physiology, University of Urbino Carlo Bo, I-61029, Urbino, Italy
| | - Michael Di Palma
- Department of Biomolecular Sciences, Section of Physiology, University of Urbino Carlo Bo, I-61029, Urbino, Italy
| | - Stefania Saccomanno
- Department of Gastroenterology, Marche Polytechnic University, Ancona, Italy
| | - Desirée Bartolini
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Pierangelo Torquato
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Gabriele Ruffolo
- Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy
| | - Fabiola Olivieri
- Department of Molecular and Clinical Sciences, Marche Polytechnic University, Ancona, Italy.,Center of Clinical Pathology and Innovative Therapy, INRCA-IRCCS, Ancona, Italy
| | - Francesco Galli
- Department of Pharmaceutical Sciences, University of Perugia, Perugia, Italy
| | - Eleonora Palma
- Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy
| | - Andrea Minelli
- Department of Biomolecular Sciences, Section of Physiology, University of Urbino Carlo Bo, I-61029, Urbino, Italy
| | - Riccardo Cuppini
- Department of Biomolecular Sciences, Section of Physiology, University of Urbino Carlo Bo, I-61029, Urbino, Italy
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Hester MS, Tulina N, Brown A, Barila G, Elovitz MA. Intrauterine inflammation reduces postnatal neurogenesis in the hippocampal subgranular zone and leads to accumulation of hilar ectopic granule cells. Brain Res 2018; 1685:51-59. [PMID: 29448014 PMCID: PMC5880291 DOI: 10.1016/j.brainres.2018.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 01/04/2018] [Accepted: 02/02/2018] [Indexed: 01/09/2023]
Abstract
Prenatal inflammation is associated with poor neurobehavioral outcomes in exposed offspring. A common route of exposure for the fetus is intrauterine infection, which is often associated with preterm birth. Hippocampal development may be particularly vulnerable to an inflammatory insult during pregnancy as this region remains highly neurogenic both prenatally and postnatally. These studies sought to determine if intrauterine inflammation specifically altered hippocampal neurogenesis and migration of newly produced granule neurons during the early postnatal period. Microglial and astroglial cell populations known to play a role in the regulation of postnatal neurogenesis were also examined. We show that intrauterine inflammation significantly reduced hippocampal neurogenesis between postnatal days 7 (P7) and P14 as well as decreased granule cell density at P28. Ectopic migration of granule cells was observed in LPS-exposed mice at P14, but not at P28. Intrauterine inflammation had no effect on hippocampal astrocyte or microglia density or on apoptosis rate at the postnatal time points examined. Thus, exposure to intrauterine inflammation disrupts early postnatal neurogenesis and leads to aberrant migration of newly born granule cells.
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Affiliation(s)
- Michael S Hester
- Maternal and Child Health Research Center, Department of Obstetrics and Gynecology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Natalia Tulina
- Maternal and Child Health Research Center, Department of Obstetrics and Gynecology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Amy Brown
- Maternal and Child Health Research Center, Department of Obstetrics and Gynecology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Guillermo Barila
- Maternal and Child Health Research Center, Department of Obstetrics and Gynecology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michal A Elovitz
- Maternal and Child Health Research Center, Department of Obstetrics and Gynecology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
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Endoplasmic Reticulum Stress Contributes to the Loss of Newborn Hippocampal Neurons after Traumatic Brain Injury. J Neurosci 2018; 38:2372-2384. [PMID: 29386258 DOI: 10.1523/jneurosci.1756-17.2018] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 12/17/2017] [Accepted: 01/24/2018] [Indexed: 01/24/2023] Open
Abstract
Adult hippocampal neurogenesis has been shown to be required for certain types of cognitive function. For example, studies have shown that these neurons are critical for pattern separation, the ability to store similar experiences as distinct memories. Although traumatic brain injury (TBI) has been shown to cause the loss of newborn hippocampal neurons, the signaling pathway(s) that triggers their death is unknown. Endoplasmic reticulum (ER) stress activates the PERK-eIF2α pathway that acts to restore ER function and improve cell survival. However, unresolved/intense ER stress activates C/EBP homologous protein (CHOP), leading to cell death. We show that TBI causes the death of hippocampal newborn neurons via CHOP. Using CHOP KO mice, we show that loss of CHOP markedly reduces newborn neuron loss after TBI. Injured CHOP mice performed significantly better in a context fear discrimination task compared with injured wild-type mice. In contrast, the PERK inhibitor GSK2606414 exacerbated doublecortin cell loss and worsened contextual discrimination. Administration of guanabenz (which reduces ER stress) to injured male rats reduced the loss of newborn neurons and improved one-trial contextual fear memory. Interestingly, we also found that the surviving newborn neurons in brain-injured animals had dendritic loss, which was not observed in injured CHOP KO mice or in animals treated with guanabenz. These results indicate that ER stress plays a key role in the death of newborn neurons after TBI. Further, these findings indicate that ER stress can alter dendritic arbors, suggesting a role for ER stress in neuroplasticity and dendritic pathologies.SIGNIFICANCE STATEMENT The hippocampus, a structure in the temporal lobe, is critical for learning and memory. The hippocampus is one of only two areas in which neurons are generated in the adult brain. These newborn neurons are required for certain types of memory, and are particularly vulnerable to traumatic brain injury (TBI). However, the mechanism(s) that causes the loss of these cells after TBI is poorly understood. We show that endoplasmic reticulum (ER) stress pathways are activated in newborn neurons after TBI, and that manipulation of the CHOP cascade improves newborn neuron survival and cognitive outcome. These results suggest that treatments that prevent/resolve ER stress may be beneficial in treating TBI-triggered memory dysfunction.
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Hamilton LK, Fernandes KJL. Neural stem cells and adult brain fatty acid metabolism: Lessons from the 3xTg model of Alzheimer's disease. Biol Cell 2017; 110:6-25. [DOI: 10.1111/boc.201700037] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 09/24/2017] [Accepted: 09/26/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Laura K. Hamilton
- Department of Neurosciences; Faculty of Medicine; University of Montreal; Montreal Canada
- The Research Center of the University of Montreal Hospital (CRCHUM); Montreal Canada
| | - Karl J. L. Fernandes
- Department of Neurosciences; Faculty of Medicine; University of Montreal; Montreal Canada
- The Research Center of the University of Montreal Hospital (CRCHUM); Montreal Canada
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Borroto-Escuela DO, DuPont CM, Li X, Savelli D, Lattanzi D, Srivastava I, Narváez M, Di Palma M, Barbieri E, Andrade-Talavera Y, Cuppini R, Odagaki Y, Palkovits M, Ambrogini P, Lindskog M, Fuxe K. Disturbances in the FGFR1-5-HT1A Heteroreceptor Complexes in the Raphe-Hippocampal 5-HT System Develop in a Genetic Rat Model of Depression. Front Cell Neurosci 2017; 11:309. [PMID: 29066953 PMCID: PMC5641403 DOI: 10.3389/fncel.2017.00309] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/19/2017] [Indexed: 12/04/2022] Open
Abstract
The FGFR1-5-HT1A heteroreceptor complexes are involved in neuroplasticity in the rat hippocampus and in the mesencephalic raphe 5-HT nerve cells. There exists a 5-HT1A protomer enhancement of FGFR1 protomer signaling. Acute and 10 day treatment with intracerebroventricular (i.c.v.) FGF-2 and the 5-HT1A agonist 8-OH-DPAT produced enhanced antidepressant effects in the forced swim test (FST). We studied in the current work the disturbances in the FGFR1-5-HT1A heterocomplexes in a genetic rat model of depression, the Flinders sensitive line (FSL) rats of Sprague-Dawley (SD) origin, by means of neurochemical, neurophysiological and behavioral techniques. In control SD rats, the FGFR1 agonist SUN11602 and FGF2 produced a significant reduction of G protein-coupled inwardly rectifying K+ channel (GIRK) currents induced by 8-OH-DPAT in the CA1 area of the hippocampus. In FSL rats, only i.c.v. 8-OH-DPAT alone treatment produced a significant reduction in the immobility time. The combined i.c.v. treatment (FGF2 + 8-OH-DPAT) in FSL rats did not cause a significant decrease in immobility time in the FST. However, in the SD rats this combined treatment produced a significant reduction. Furthermore, in the FSL rat a significant increase in the density of FGFR1-5-HT1A proximity ligation assay (PLA) positive clusters was only found after i.c.v. 8-OH-DPAT treatment alone in the CA2 and CA3 areas. In the SD rat a significant increase in the density of specific PLA clusters was only observed in the CA2 area of the i.c.v. combined treatment (FGF2 + 8-OH-DPAT) group. No treatment led to significant changes in the PLA clusters of the dorsal raphe in the FSL rat. However, significant changes in the density of specific PLA clusters were only found in the dorsal raphe of SD rats after combined treatment and treatment with 8-OH-DPAT alone. The results indicate that in FSL rats compared with SD rats alterations may develop in the ability of 8-OH-DPAT and combined FGFR1 and 5-HT1A agonist treatment to increase the density of FGFR1-5-HT1A heteroreceptor complexes of the dorsal raphe. It is proposed that such deficits in FSL rats may possibly reflect a failure of the combined agonist treatment to uncouple the 5-HT1A autoreceptors from the GIRK channels. This may contribute to the failure of producing antidepressant-like effects in the FSL rat by combined agonist treatment as seen in the SD rat. The antidepressant-like effects seen with the 5-HT1A agonist alone treatment in FSL but not in SD rats may instead involve significant increases in the FGFR1-5-HT1A complexes of the CA2 and CA3 areas of the hippocampus.
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Affiliation(s)
- Dasiel O Borroto-Escuela
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy.,Grupo Bohío-Estudio, Observatorio Cubano de Neurociencias, Yaguajay, Cuba
| | - Caitlin M DuPont
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Xiang Li
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - David Savelli
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Davide Lattanzi
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Ipsit Srivastava
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Manuel Narváez
- Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Universidad de Málaga, Málaga, Spain
| | - Michael Di Palma
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Elisa Barbieri
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Yuniesky Andrade-Talavera
- Neuronal Oscillations Laboratory, Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Karolinska Institutet, Stockholm, Sweden
| | - Riccardo Cuppini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Yuji Odagaki
- Department of Psychiatry, Faculty of Medicine, Saitama Medical University, Saitama, Japan
| | - Miklos Palkovits
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Patrizia Ambrogini
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Maria Lindskog
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Kjell Fuxe
- Division of Cellular and Molecular Neurochemistry, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Spencer WC, Deneris ES. Regulatory Mechanisms Controlling Maturation of Serotonin Neuron Identity and Function. Front Cell Neurosci 2017; 11:215. [PMID: 28769770 PMCID: PMC5515867 DOI: 10.3389/fncel.2017.00215] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/05/2017] [Indexed: 11/29/2022] Open
Abstract
The brain serotonin (5-hydroxytryptamine; 5-HT) system has been extensively studied for its role in normal physiology and behavior, as well as, neuropsychiatric disorders. The broad influence of 5-HT on brain function, is in part due to the vast connectivity pattern of 5-HT-producing neurons throughout the CNS. 5-HT neurons are born and terminally specified midway through embryogenesis, then enter a protracted period of maturation, where they functionally integrate into CNS circuitry and then are maintained throughout life. The transcriptional regulatory networks controlling progenitor cell generation and terminal specification of 5-HT neurons are relatively well-understood, yet the factors controlling 5-HT neuron maturation are only recently coming to light. In this review, we first provide an update on the regulatory network controlling 5-HT neuron development, then delve deeper into the properties and regulatory strategies governing 5-HT neuron maturation. In particular, we discuss the role of the 5-HT neuron terminal selector transcription factor (TF) Pet-1 as a key regulator of 5-HT neuron maturation. Pet-1 was originally shown to positively regulate genes needed for 5-HT synthesis, reuptake and vesicular transport, hence 5-HT neuron-type transmitter identity. It has now been shown to regulate, both positively and negatively, many other categories of genes in 5-HT neurons including ion channels, GPCRs, transporters, neuropeptides, and other transcription factors. Its function as a terminal selector results in the maturation of 5-HT neuron excitability, firing characteristics, and synaptic modulation by several neurotransmitters. Furthermore, there is a temporal requirement for Pet-1 in the control of postmitotic gene expression trajectories thus indicating a direct role in 5-HT neuron maturation. Proper regulation of the maturation of cellular identity is critical for normal neuronal functioning and perturbations in the gene regulatory networks controlling these processes may result in long-lasting changes in brain function in adulthood. Further study of 5-HT neuron gene regulatory networks is likely to provide additional insight into how neurons acquire their mature identities and how terminal selector-type TFs function in postmitotic vertebrate neurons.
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Affiliation(s)
- William C Spencer
- Department of Neurosciences, Case Western Reserve UniversityCleveland, OH, United States
| | - Evan S Deneris
- Department of Neurosciences, Case Western Reserve UniversityCleveland, OH, United States
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Vidal V, García-Cerro S, Martínez P, Corrales A, Lantigua S, Vidal R, Rueda N, Ozmen L, Hernández MC, Martínez-Cué C. Decreasing the Expression of GABA A α5 Subunit-Containing Receptors Partially Improves Cognitive, Electrophysiological, and Morphological Hippocampal Defects in the Ts65Dn Model of Down Syndrome. Mol Neurobiol 2017; 55:4745-4762. [PMID: 28717969 DOI: 10.1007/s12035-017-0675-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 06/27/2017] [Indexed: 12/31/2022]
Abstract
Trisomy 21 or Down syndrome (DS) is the most common cause of intellectual disability of a genetic origin. The Ts65Dn (TS) mouse, which is the most commonly used and best-characterized mouse model of DS, displays many of the cognitive, neuromorphological, and biochemical anomalies that are found in the human condition. One of the mechanisms that have been proposed to be responsible for the cognitive deficits in this mouse model is impaired GABA-mediated inhibition. Because of the well-known modulatory role of GABAA α5 subunit-containing receptors in cognitive processes, these receptors are considered to be potential targets for improving the intellectual disability in DS. The chronic administration of GABAA α5-negative allosteric modulators has been shown to be procognitive without anxiogenic or proconvulsant side effects. In the present study, we use a genetic approach to evaluate the contribution of GABAA α5 subunit-containing receptors to the cognitive, electrophysiological, and neuromorphological deficits in TS mice. We show that reducing the expression of GABAA α5 receptors by deleting one or two copies of the Gabra5 gene in TS mice partially ameliorated the cognitive impairments, improved long-term potentiation, enhanced neural differentiation and maturation, and normalized the density of the GABAergic synapse markers. Reducing the gene dosage of Gabra5 in TS mice did not induce motor alterations and anxiety or affect the viability of the mice. Our results provide further evidence of the role of GABAA α5 receptor-mediated inhibition in cognitive impairment in the TS mouse model of DS.
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Affiliation(s)
- Verónica Vidal
- Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad deCantabria, Santander, Spain
| | - Susana García-Cerro
- Departamento de Fundamentos Clínicos, Unidad de Farmacología, Universitat de Barcelona, Barcelona, Spain
| | - Paula Martínez
- Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad deCantabria, Santander, Spain
| | - Andrea Corrales
- Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad deCantabria, Santander, Spain
| | - Sara Lantigua
- Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad deCantabria, Santander, Spain
| | - Rebeca Vidal
- Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad deCantabria, Santander, Spain.,Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC (Universidad de Cantabria, CSIC, SODERCAN), Santander, Spain.,Centro de Investigacion Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain
| | - Noemí Rueda
- Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad deCantabria, Santander, Spain
| | - Laurence Ozmen
- Pharma Research and Early Development, Hoffman-La Roche Ltd., Basel, Switzerland
| | | | - Carmen Martínez-Cué
- Departamento de Fisiología y Farmacología, Facultad de Medicina, Universidad deCantabria, Santander, Spain.
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Imoto Y, Segi-Nishida E, Suzuki H, Kobayashi K. Rapid and stable changes in maturation-related phenotypes of the adult hippocampal neurons by electroconvulsive treatment. Mol Brain 2017; 10:8. [PMID: 28253930 PMCID: PMC5335812 DOI: 10.1186/s13041-017-0288-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 02/22/2017] [Indexed: 12/28/2022] Open
Abstract
Electroconvulsive therapy (ECT) is a highly effective and fast-acting treatment for depression. Despite a long history of clinical use, its mechanism of action remains poorly understood. Recently, a novel cellular mechanism of antidepressant action has been proposed: the phenotype of mature brain neurons is transformed to immature-like one by antidepressant drug treatments. We show here that electroconvulsive stimulation (ECS), an animal model of ECT, causes profound changes in maturation-related phenotypes of neurons in the hippocampal dentate gyrus of adult mice. Single ECS immediately reduced expression of mature neuronal markers in almost entire population of dentate granule cells. After ECS treatments, granule cells showed some of physiological properties characteristic of immature granule cells such as higher somatic intrinsic excitability and smaller frequency facilitation at the detate-to-CA3 synapse. The rapid downregulation of maturation markers was suppressed by antagonizing glutamate NMDA receptors, but not by perturbing the serotonergic system. While single ECS caused short-lasting effects, repeated ECS induced stable changes in the maturation-related phenotypes lasting more than 2 weeks along with enhancement of synaptic excitation of granule cells. Augmentation of synaptic inhibition or blockade of NMDA receptors after repeated ECS facilitated regaining the initial mature phenotype, suggesting a role for endogenous neuronal excitation in maintaining the altered maturation-related phenotype probably via NMDA receptor activation. These results suggest that brief neuronal activation by ECS induces "dematuration" of the mature granule cells and that enhanced endogenous excitability is likely to support maintenance of such a demature state. The global increase in neuronal excitability accompanying this process may be relevant to the high efficacy of ECT.
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Affiliation(s)
- Yuki Imoto
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Eri Segi-Nishida
- Center for Integrative Education in Pharmacy and Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan. .,Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, Katsushika-ku, Tokyo, Japan.
| | - Hidenori Suzuki
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, Sendagi, Bunkyō, Tokyo, Japan.,Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Saitama, Japan
| | - Katsunori Kobayashi
- Department of Pharmacology, Graduate School of Medicine, Nippon Medical School, Sendagi, Bunkyō, Tokyo, Japan. .,Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Saitama, Japan.
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40
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Yin M, Chen Y, Zheng H, Pu T, Marshall C, Wu T, Xiao M. Assessment of mouse cognitive and anxiety-like behaviors and hippocampal inflammation following a repeated and intermittent paradoxical sleep deprivation procedure. Behav Brain Res 2017; 321:69-78. [DOI: 10.1016/j.bbr.2016.12.034] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/21/2016] [Accepted: 12/25/2016] [Indexed: 12/12/2022]
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41
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Ambrogini P, Betti M, Galati C, Di Palma M, Lattanzi D, Savelli D, Galli F, Cuppini R, Minelli A. α-Tocopherol and Hippocampal Neural Plasticity in Physiological and Pathological Conditions. Int J Mol Sci 2016; 17:E2107. [PMID: 27983697 PMCID: PMC5187907 DOI: 10.3390/ijms17122107] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/01/2016] [Accepted: 12/09/2016] [Indexed: 12/25/2022] Open
Abstract
Neuroplasticity is an "umbrella term" referring to the complex, multifaceted physiological processes that mediate the ongoing structural and functional modifications occurring, at various time- and size-scales, in the ever-changing immature and adult brain, and that represent the basis for fundamental neurocognitive behavioral functions; in addition, maladaptive neuroplasticity plays a role in the pathophysiology of neuropsychiatric dysfunctions. Experiential cues and several endogenous and exogenous factors can regulate neuroplasticity; among these, vitamin E, and in particular α-tocopherol (α-T), the isoform with highest bioactivity, exerts potent effects on many plasticity-related events in both the physiological and pathological brain. In this review, the role of vitamin E/α-T in regulating diverse aspects of neuroplasticity is analyzed and discussed, focusing on the hippocampus, a brain structure that remains highly plastic throughout the lifespan and is involved in cognitive functions. Vitamin E-mediated influences on hippocampal synaptic plasticity and related cognitive behavior, on post-natal development and adult hippocampal neurogenesis, as well as on cellular and molecular disruptions in kainate-induced temporal seizures are described. Besides underscoring the relevance of its antioxidant properties, non-antioxidant functions of vitamin E/α-T, mainly involving regulation of cell signaling molecules and their target proteins, have been highlighted to help interpret the possible mechanisms underlying the effects on neuroplasticity.
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Affiliation(s)
- Patrizia Ambrogini
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - Michele Betti
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - Claudia Galati
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - Michael Di Palma
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - Davide Lattanzi
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - David Savelli
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - Francesco Galli
- Department of Pharmaceutical Sciences, University of Perugia, 06123 Perugia, Italy.
| | - Riccardo Cuppini
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
| | - Andrea Minelli
- Department of Biomolecular Sciences, University of Urbino, 61029 Urbino, Italy.
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Diamantaki M, Frey M, Berens P, Preston-Ferrer P, Burgalossi A. Sparse activity of identified dentate granule cells during spatial exploration. eLife 2016; 5. [PMID: 27692065 PMCID: PMC5077296 DOI: 10.7554/elife.20252] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 10/01/2016] [Indexed: 01/20/2023] Open
Abstract
In the dentate gyrus - a key component of spatial memory circuits - granule cells (GCs) are known to be morphologically diverse and to display heterogeneous activity profiles during behavior. To resolve structure-function relationships, we juxtacellularly recorded and labeled single GCs in freely moving rats. We found that the vast majority of neurons were silent during exploration. Most active GCs displayed a characteristic spike waveform, fired at low rates and showed spatial activity. Primary dendritic parameters were sufficient for classifying neurons as active or silent with high accuracy. Our data thus support a sparse coding scheme in the dentate gyrus and provide a possible link between structural and functional heterogeneity among the GC population.
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Affiliation(s)
- Maria Diamantaki
- Werner-Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Graduate Training Centre of Neuroscience - IMPRS, University of Tübingen, Tübingen, Germany
| | - Markus Frey
- Werner-Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Philipp Berens
- Werner-Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.,Bernstein Centre for Computational Neuroscience, University of Tübingen, Tübingen, Germany
| | - Patricia Preston-Ferrer
- Werner-Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Andrea Burgalossi
- Werner-Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
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Øverli Ø, Sørensen C. On the Role of Neurogenesis and Neural Plasticity in the Evolution of Animal Personalities and Stress Coping Styles. BRAIN, BEHAVIOR AND EVOLUTION 2016; 87:167-174. [DOI: 10.1159/000447085] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Individual variation in how animals react to stress and environmental change has become a central topic in a wide range of biological disciplines, from evolutionary ecology to biomedicine. Such variation manifests phenotypically as correlated trait-clusters (referred to as coping styles, behavioral syndromes, shyness-boldness, or personality traits). Thresholds for switching from active coping (fight-flight) to inhibition and passive behavior when exposed to stress depend on experience and genetic factors. Comparative research has revealed a range of neuroendocrine-behavioral associations which are conserved throughout the vertebrate subphylum, including factors affecting perception, learning, and memory of stimuli and events. Here we review conserved aspects of the contribution of neurogenesis and other aspects of neural plasticity to stress coping. In teleost fish, brain cell proliferation and neurogenesis have received recent attention. This work reveals that brain cell proliferation and neurogenesis are associated with heritable variation in stress coping style, and they are also differentially affected by short- and long-term stress in a biphasic manner. Routine-dependent and inflexible behavior in proactive individuals is associated with limited neural plasticity. These evolutionarily conserved relationships hold the potential to illuminate the biological background for stress-related neurobiological disorders.
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Mental and physical skill training increases neurogenesis via cell survival in the adolescent hippocampus. Brain Res 2016; 1654:95-101. [PMID: 27531182 DOI: 10.1016/j.brainres.2016.08.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 08/10/2016] [Accepted: 08/12/2016] [Indexed: 12/30/2022]
Abstract
The adolescent hippocampus produces thousands more new neurons daily than the adult, yet many die within weeks of their generation (Cameron and McCay, 2001; Curlik, DiFeo & Shors, 2014; Shors et al., 2016). Learning new skills can increase their survival. The present study tested the effects of physical skill training on the survival of these newly generated cells in males and female rodents during puberty. Newly generated cells were labeled with BrdU, a marker of cell mitosis, and training began one week later, just as the new cells begin to die. Significantly more BrdU-labeled cells were present in the hippocampus of both sexes after engaging in the physical training experiences. The young animals were able to maintain their balance on a modified rotarod task throughout most trials of training and as a consequence expended considerable energy and endurance during each training trial. These data suggest that a combination of both exercise and skill training can increase brain plasticity through increases in neurogenesis in the adolescent hippocampus. This finding supports the premise behind a clinical intervention known as MAP Training, which combines mental and physical training to enhance brain health in humans (Shors et al., 2014; Alderman et al., 2016). Although theoretical at this stage, the positive consequences of MAP Training for brain function may be mediated through neurogenesis. This article is part of a Special Issue entitled SI: Adolescent plasticity.
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Zhang D, Wang X, Lu XY. Adiponectin Exerts Neurotrophic Effects on Dendritic Arborization, Spinogenesis, and Neurogenesis of the Dentate Gyrus of Male Mice. Endocrinology 2016; 157:2853-69. [PMID: 27187175 PMCID: PMC4929553 DOI: 10.1210/en.2015-2078] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The hippocampus, a brain region critical for learning, memory and emotional processing, maintains its capacity to undergo structural plasticity throughout life. Hippocampal structural plasticity can be modulated by a number of intrinsic and extrinsic factors. This study investigated the effects of adiponectin, an adipocyte-derived hormone, on dendritic growth, arborization, and spinogenesis in mature granule neurons of the hippocampal dentate gyrus generated during embryonic (early-born) or early postnatal (late-born) stages. We found that adiponectin deficiency reduced dendritic length, branching and spine density of granule neurons. The reduction was more evident in early-born granule neurons than in late-born granule neurons. Intracerebroventricular infusion of adiponectin for 1 week increased of dendritic spines and arbor complexity in late-born granule neurons. Moreover, adiponectin deficiency decreased the production of adult-born new granule neurons through suppressing neural progenitor cell proliferation and differentiation, whereas intracerebroventricular adiponectin infusion increased the proliferation of neural progenitor cells in adult dentate gyrus. These results suggest that adiponectin plays an important role in dendritic spine remodeling and neurogenesis in the dentate gyrus.
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Affiliation(s)
- Di Zhang
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, Texas 78229
| | - Xuezhen Wang
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, Texas 78229
| | - Xin-Yun Lu
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, Texas 78229
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The effects of hormones and physical exercise on hippocampal structural plasticity. Front Neuroendocrinol 2016; 41:23-43. [PMID: 26989000 DOI: 10.1016/j.yfrne.2016.03.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 03/02/2016] [Accepted: 03/08/2016] [Indexed: 01/22/2023]
Abstract
The hippocampus plays an integral role in certain aspects of cognition. Hippocampal structural plasticity and in particular adult hippocampal neurogenesis can be influenced by several intrinsic and extrinsic factors. Here we review how hormones (i.e., intrinsic modulators) and physical exercise (i.e., an extrinsic modulator) can differentially modulate hippocampal plasticity in general and adult hippocampal neurogenesis in particular. Specifically, we provide an overview of the effects of sex hormones, stress hormones, and metabolic hormones on hippocampal structural plasticity and adult hippocampal neurogenesis. In addition, we also discuss how physical exercise modulates these forms of hippocampal plasticity, giving particular emphasis on how this modulation can be affected by variables such as exercise regime, duration, and intensity. Understanding the neurobiological mechanisms underlying the modulation of hippocampal structural plasticity by intrinsic and extrinsic factors will impact the design of new therapeutic approaches aimed at restoring hippocampal plasticity following brain injury or neurodegeneration.
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Nozaki K, Kubo R, Furukawa Y. Serotonin modulates the excitatory synaptic transmission in the dentate granule cells. J Neurophysiol 2016; 115:2997-3007. [PMID: 26961099 DOI: 10.1152/jn.00064.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 03/04/2016] [Indexed: 01/23/2023] Open
Abstract
Serotonergic fibers from the raphe nuclei project to the hippocampal formation, the activity of which is known to modulate the inhibitory interneurons in the dentate gyrus. On the other hand, serotonergic modulation of the excitatory synapses in the dentate gyrus is not well examined. In the present study, we examined the effects of 5-HT on the excitatory postsynaptic potentials (EPSPs) in the dentate granule cells evoked by the selective stimulation of the lateral perforant path (LPP), the medial perforant path (MPP), or the mossy cell fibers (MCF). 5-HT depressed the amplitude of unitary EPSPs (uEPSPs) evoked by the stimulation of LPP or MPP, whereas uEPSPs evoked by MCF stimulation were little affected. The effect was partly explained by the decrease of the resting membrane resistance following the activation of 5-HT1A receptors, which was confirmed by computer simulations. We also found that the probability of evoking uEPSP by LPP stimulation but not MPP or MCF stimulation was reduced by 5-HT and that the paired-pulse ratio of LPP-evoked EPSP but not that of MPP- or MCF-evoked ones was increased by 5-HT. These effects were blocked by 5-HT2 antagonist, suggesting that the transmitter release in the LPP-granule cell synapse is inhibited by the activation of 5-HT2 receptors. The present results suggest that 5-HT can modulate the EPSPs in the dentate granule cells by at least two distinct mechanisms.
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Affiliation(s)
- Kanako Nozaki
- Laboratory of Neurobiology, Faculty of Integrated Arts and Sciences, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Japan; and
| | - Reika Kubo
- Department of Neurophysiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Kasumi, Naka-ku, Hiroshima, Japan
| | - Yasuo Furukawa
- Laboratory of Neurobiology, Faculty of Integrated Arts and Sciences, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Japan; and
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Gros A, Veyrac A, Laroche S. [Brain and memory: new neurons to remember]. Biol Aujourdhui 2016; 209:229-248. [PMID: 26820830 DOI: 10.1051/jbio/2015028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Indexed: 06/05/2023]
Abstract
A defining characteristic of the brain is its remarkable capacity to undergo activity-dependent functional and structural remodelling via mechanisms of plasticity that form the basis of our capacity to encode and retain memories. The prevailing model of how our brain stores new information about relationships between events or new abstract constructs suggests it resides in activity-driven modifications of synaptic strength and remodelling of neural networks brought about by cellular and molecular changes within the neurons activated during learning. To date, the idea that a form of activity-dependent synaptic plasticity known as long-term potentiation, or LTP, and the associated synaptic growth play a central role in the laying down of memories has received considerable support. Beyond this mechanism of plasticity at the synapse, adult neurogenesis, i.e. the birth and growth of new neurons, is another form of neural plasticity that occurs continuously in defined brain regions such as the dentate gyrus of the hippocampus. Here, based on work in the hippocampus, we review the processes and mechanisms of the generation and selection of new neurons in the adult brain and the accumulating evidence that supports the idea that this form of neural plasticity is essential to store and lead to retrievable hippocampal-dependent memories.
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Affiliation(s)
- Alexandra Gros
- Institut des Neurosciences Paris-Saclay, UMR 9197, CNRS, Université Paris Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Alexandra Veyrac
- Centre de Recherche en Neurosciences de Lyon, UMR 5292 CNRS, INSERM U1028, Université Lyon 1, 69366 Lyon, France
| | - Serge Laroche
- Institut des Neurosciences Paris-Saclay, UMR 9197, CNRS, Université Paris Sud, Université Paris-Saclay, 91405 Orsay, France
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49
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Sartini S, Lattanzi D, Ambrogini P, Di Palma M, Galati C, Savelli D, Polidori E, Calcabrini C, Rocchi MBL, Sestili P, Cuppini R. Maternal creatine supplementation affects the morpho-functional development of hippocampal neurons in rat offspring. Neuroscience 2015; 312:120-9. [PMID: 26592720 DOI: 10.1016/j.neuroscience.2015.11.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 11/05/2015] [Accepted: 11/10/2015] [Indexed: 12/28/2022]
Abstract
Creatine supplementation has been shown to protect neurons from oxidative damage due to its antioxidant and ergogenic functions. These features have led to the hypothesis of creatine supplementation use during pregnancy as prophylactic treatment to prevent CNS damage, such as hypoxic-ischemic encephalopathy. Unfortunately, very little is known on the effects of creatine supplementation during neuron differentiation, while in vitro studies revealed an influence on neuron excitability, leaving the possibility of creatine supplementation during the CNS development an open question. Using a multiple approach, we studied the hippocampal neuron morphological and functional development in neonatal rats born by dams supplemented with 1% creatine in drinking water during pregnancy. CA1 pyramidal neurons of supplemented newborn rats showed enhanced dendritic tree development, increased LTP maintenance, larger evoked-synaptic responses, and higher intrinsic excitability in comparison to controls. Moreover, a faster repolarizing phase of action potential with the appearance of a hyperpolarization were recorded in neurons of the creatine-treated group. Consistently, CA1 neurons of creatine exposed pups exhibited a higher maximum firing frequency than controls. In summary, we found that creatine supplementation during pregnancy positively affects morphological and electrophysiological development of CA1 neurons in offspring rats, increasing neuronal excitability. Altogether, these findings emphasize the need to evaluate the benefits and the safety of maternal intake of creatine in humans.
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Affiliation(s)
- S Sartini
- University of Urbino Carlo Bo, Dept. of Earth, Life and Environmental Sciences, Campus Scientifico "Enrico Mattei", via Ca' le Suore, 2, 61029 Urbino, Italy.
| | - D Lattanzi
- University of Urbino Carlo Bo, Dept. of Earth, Life and Environmental Sciences, Campus Scientifico "Enrico Mattei", via Ca' le Suore, 2, 61029 Urbino, Italy
| | - P Ambrogini
- University of Urbino Carlo Bo, Dept. of Earth, Life and Environmental Sciences, Campus Scientifico "Enrico Mattei", via Ca' le Suore, 2, 61029 Urbino, Italy
| | - M Di Palma
- University of Urbino Carlo Bo, Dept. of Earth, Life and Environmental Sciences, Campus Scientifico "Enrico Mattei", via Ca' le Suore, 2, 61029 Urbino, Italy
| | - C Galati
- University of Urbino Carlo Bo, Dept. of Earth, Life and Environmental Sciences, Campus Scientifico "Enrico Mattei", via Ca' le Suore, 2, 61029 Urbino, Italy
| | - D Savelli
- University of Urbino Carlo Bo, Dept. of Earth, Life and Environmental Sciences, Campus Scientifico "Enrico Mattei", via Ca' le Suore, 2, 61029 Urbino, Italy
| | - E Polidori
- University of Urbino Carlo Bo, Dept. of Biomolecular Sciences, via I Maggetti, 26, 61029 Urbino, Italy
| | - C Calcabrini
- University of Urbino Carlo Bo, Dept. of Biomolecular Sciences, via I Maggetti, 26, 61029 Urbino, Italy
| | - M B L Rocchi
- University of Urbino Carlo Bo, Dept. of Biomolecular Sciences, via I Maggetti, 26, 61029 Urbino, Italy
| | - P Sestili
- University of Urbino Carlo Bo, Dept. of Biomolecular Sciences, via I Maggetti, 26, 61029 Urbino, Italy
| | - R Cuppini
- University of Urbino Carlo Bo, Dept. of Earth, Life and Environmental Sciences, Campus Scientifico "Enrico Mattei", via Ca' le Suore, 2, 61029 Urbino, Italy
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Molecular Biomarkers for Embryonic and Adult Neural Stem Cell and Neurogenesis. BIOMED RESEARCH INTERNATIONAL 2015; 2015:727542. [PMID: 26421301 PMCID: PMC4569757 DOI: 10.1155/2015/727542] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 11/19/2014] [Indexed: 02/07/2023]
Abstract
The procedure of neurogenesis has made numerous achievements in the past decades, during which various molecular biomarkers have been emerging and have been broadly utilized for the investigation of embryonic and adult neural stem cell (NSC). Nevertheless, there is not a consistent and systematic illustration to depict the functional characteristics of the specific markers expressed in distinct cell types during the different stages of neurogenesis. Here we gathered and generalized a series of NSC biomarkers emerging during the procedures of embryonic and adult neural stem cell, which may be used to identify the subpopulation cells with distinguishing characters in different timeframes of neurogenesis. The identifications of cell patterns will provide applications to the detailed investigations of diverse developmental cell stages and the extents of cell differentiation, which will facilitate the tracing of cell time-course and fate determination of specific cell types and promote the further and literal discoveries of embryonic and adult neurogenesis. Meanwhile, via the utilization of comprehensive applications under the aiding of the systematic knowledge framework, researchers may broaden their insights into the derivation and establishment of novel technologies to analyze the more detailed process of embryogenesis and adult neurogenesis.
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