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Nogueira M, Ferreira Golbert DC, Menezes R, Nóbrega de Almeida R, Galvão-Coelho NL, Siroky AN, Lima TZ, Maia H, Leão KE, Leão RN. Serotonergic psychedelic 5-MeO-DMT alters plasticity-related gene expression and generates anxiolytic effects in stressed mice. Mol Psychiatry 2024:10.1038/s41380-024-02655-w. [PMID: 38969716 DOI: 10.1038/s41380-024-02655-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 06/21/2024] [Accepted: 06/27/2024] [Indexed: 07/07/2024]
Abstract
Serotonergic psychedelics have potential therapeutic effects in treating anxiety and mood disorders, often after a single dose, and are suggested to have plasticity-inducing action. However, a comprehensive mechanism of action is still lacking. Here, we investigated how a single dose of the short-acting 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) acts on gene expression from microdissected brain regions (anterior cingulate cortex - ACC; basolateral amygdala - BLA; ventral hippocampus CA1 region - vCA1 and dentate gyrus-DG) of naive and stressed mice. Specifically, we compared gene expression of Arc, Zif268, BDNF, CREB, mTORC1, NR2A, TRIP8b, and NFkB in mice injected with 5-MeO-DMT or saline at different time points (1 h, 5 h, or 5 days prior). 5-MeO-DMT altered mRNA expression of immediate early genes Arc and ZiF268 in the ACC, BLA, and vCA1, while NR2A expression was decreased after 5 h in the vCA1. We also found a long-term increase in TRIP8b, a gene related to the modulation of neuronal activity, in the vCA1 after 5 days. Behaviorally, 5-MeO-DMT treated mice showed mixed anxiolytic and anxiogenic effects in the elevated plus maze and open field test 24 h or 5 days after treatment. However, pre-treated mice subjected to acute stress showed both lower corticosterone levels and robust anxiolytic effects of 5-MeO-DMT administration. Together, our findings provide insights into the molecular actions of 5-MeO-DMT in the brain related to anxiolytic effects of behavior.
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Affiliation(s)
- Margareth Nogueira
- Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
- Hearing and Neuronal Activity Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Daiane C Ferreira Golbert
- Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
- Sleep, Dreams and Memory Laboratory, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Richardson Menezes
- Automation and Robotics Laboratory, School of Science and Technology, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Raíssa Nóbrega de Almeida
- Laboratory of Hormone Measurement, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Nicole L Galvão-Coelho
- Laboratory of Hormone Measurement, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Andressa N Siroky
- Department of Statistics, Exact and Earth Sciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Thiago Z Lima
- Hearing and Neuronal Activity Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
- Department of Statistics, Exact and Earth Sciences Center, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Helton Maia
- Automation and Robotics Laboratory, School of Science and Technology, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Katarina E Leão
- Hearing and Neuronal Activity Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
| | - Richardson N Leão
- Neurodynamics Lab, Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
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Ehtezazi T, Rahman K, Davies R, Leach AG. The Pathological Effects of Circulating Hydrophobic Bile Acids in Alzheimer's Disease. J Alzheimers Dis Rep 2023; 7:173-211. [PMID: 36994114 PMCID: PMC10041467 DOI: 10.3233/adr-220071] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
Recent clinical studies have revealed that the serum levels of toxic hydrophobic bile acids (deoxy cholic acid, lithocholic acid [LCA], and glycoursodeoxycholic acid) are significantly higher in patients with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) when compared to control subjects. The elevated serum bile acids may be the result of hepatic peroxisomal dysfunction. Circulating hydrophobic bile acids are able to disrupt the blood-brain barrier and promote the formation of amyloid-β plaques through enhancing the oxidation of docosahexaenoic acid. Hydrophobic bile acid may find their ways into the neurons via the apical sodium-dependent bile acid transporter. It has been shown that hydrophobic bile acids impose their pathological effects by activating farnesoid X receptor and suppressing bile acid synthesis in the brain, blocking NMDA receptors, lowering brain oxysterol levels, and interfering with 17β-estradiol actions such as LCA by binding to E2 receptors (molecular modelling data exclusive to this paper). Hydrophobic bile acids may interfere with the sonic hedgehog signaling through alteration of cell membrane rafts and reducing brain 24(S)-hydroxycholesterol. This article will 1) analyze the pathological roles of circulating hydrophobic bile acids in the brain, 2) propose therapeutic approaches, and 3) conclude that consideration be given to reducing/monitoring toxic bile acid levels in patients with AD or aMCI, prior/in combination with other treatments.
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Affiliation(s)
- Touraj Ehtezazi
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
| | - Khalid Rahman
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
| | - Rhys Davies
- The Walton Centre, NHS Foundation Trust, Liverpool, UK
| | - Andrew G Leach
- School of Pharmacy, University of Manchester, Manchester, UK
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Ni L, Zhuge F, Yang S, Ma L, Zheng A, Zhao Y, Hu L, Fu Z, Ni Y. Hydrolyzed Chicken Meat Extract Attenuates Neuroinflammation and Cognitive Impairment in Middle-Aged Mouse by Regulating M1/M2 Microglial Polarization. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:9800-9812. [PMID: 34404209 DOI: 10.1021/acs.jafc.1c03541] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Aging is the most common cause of several neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease. The pathological hallmarks of age-dependent neuropathology consist of chronic neuroinflammation, oxidative stress, gliosis, learning disability, and cognitive decline. A novel hydrolyzed bioactive peptide mixture extracted from chicken meat, that is, hydrolyzed chicken extract (HCE) has been previously demonstrated to exert neuroprotective effects in rodents and humans. However, the mechanism of HCE on age-related neurological disorders remains unclear. Herein, we aimed to clarify the impact and mechanism of isolated bioactive components (BCs) from HCE on age-dependent neuroinflammation and cognitive impairment in middle-aged mice. We found that both BC and HCE supplementation ameliorated age-induced memory loss, alleviated hippocampal neuroinflammation and oxidative stress, followed by promoting hippocampal neurogenesis in mice. BC and HCE treatment also ameliorated age-dependent morphological anomalies and alleviated microgliosis and astrogliosis. In parallel, BC and HCE treatment showed a significant decrease in the NF-κB p65 and p38 MAPK signaling, which were associated with the enhancement of antioxidative enzymes activities. Furthermore, BC treatment attenuated the neuroinflammatory phenotypes by the decrease in M1-polarized microglia and the increase in M2-polarized microglia in vivo and in vitro. In addition, we found that cyclo(Phe-Phe), one of the cyclopeptides purified from BC, showed notable anti-inflammatory effects in BV2 cells. Taken together, BC might be used as a dietary supplement for alleviating age-dependent neuropathology in middle-aged individuals.
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Affiliation(s)
- Liyang Ni
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Fen Zhuge
- Institute of Translational Medicine, The Affiliated Hospital of Hangzhou Normal University, Hangzhou 310015, China
| | - Song Yang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Lingyan Ma
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Aqian Zheng
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Yufeng Zhao
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Luting Hu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Zhengwei Fu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Yinhua Ni
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
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Fomin-Thunemann N, Kovalchuk Y, Fink S, Alsema A, Mojtahedi N, Zirdum E, Garaschuk O. Unique Functional Properties of Mature Adult-Born Neurons in the Mouse Olfactory Bulb. Stem Cell Reports 2020; 15:1333-1346. [PMID: 33217326 PMCID: PMC7724478 DOI: 10.1016/j.stemcr.2020.10.010] [Citation(s) in RCA: 3] [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: 05/04/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 11/19/2022] Open
Abstract
The rodent olfactory bulb (OB) is continuously supplied with adult-born cells maturing into GABAergic neurons. Using in vivo ratiometric Ca2+ imaging to readout ongoing and sensory-driven activity, we asked whether mature adult-born cells (mABCs) in the glomerular layer of the bulb become functionally identical to resident GABAergic (ResGABA) neurons. In awake head-restrained mice the two cell populations differed significantly in terms of ongoing spontaneous activity, with 24% of mABCs contributing to a strongly active cell cluster, absent among ResGABA cells. Odor-evoked responses of mABCs were sparse, less reliable, and had smaller amplitudes compared with ResGABA cells. The opposite was seen under anesthesia, with response reliability increasing and response size of mABCs becoming larger than that of ResGABA cells. Furthermore, ongoing activity of mABCs showed increased sensitivity to ketamine/xylazine and was selectively blocked by the antagonist of serotonin receptors methysergide. These functional features of mABCs clearly distinguish them from other OB interneurons.
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Affiliation(s)
- Natalie Fomin-Thunemann
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Yury Kovalchuk
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Stefan Fink
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Astrid Alsema
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Nima Mojtahedi
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Elizabeta Zirdum
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Institute of Physiology, Department of Neurophysiology, Eberhard Karls University of Tübingen, Tübingen, Germany.
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Bottemanne H, Claret A, Fossati P. [Ketamine, psilocybin, and rapid acting antidepressant: new promise for psychiatry?]. Encephale 2020; 47:171-178. [PMID: 33190819 DOI: 10.1016/j.encep.2020.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 07/12/2020] [Accepted: 08/08/2020] [Indexed: 12/20/2022]
Abstract
The hypothesis of monoaminergic deficiency has long dominated the conceptual framework for the development of new antidepressant strategies, but the limits of conventional antidepressant treatments targeting monoaminergic signaling have motivated the search for new antidepressant pathways. The success of ketamine in the management of depressive disorders has provoked a renewed interest in hallucinogenic substances such as psilocybin targeting the serotonergic signaling 5HT2A and neurosteroid allosteric modulator of γ-aminobutyric acid (GABAA) receptors such as brexanolone. Unlike conventional treatments, these modulators of glutamatergic, serotonergic and GABAergic systems exert a rapid antidepressant effect ranging from 24hours to a week. Apart from their clinical interest and the fantasized search for a "miracle" molecule that jointly meets the expectations of patients and clinicians, these new targets could lead to the identification of potential new biomarkers for the development of rapid-acting antidepressants and redefine therapeutic strategies in mood disorders.
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Affiliation(s)
- H Bottemanne
- Control-Interoception-Attention team, Paris Brain Institute, Institut du Cerveau (ICM), UMR 7225/UMR_S 1127, Sorbonne University/CNRS/Inserm, Paris, France.; Department of Psychiatry, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris (APHP), Paris, France.
| | - A Claret
- Department of Psychiatry, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris (APHP), Paris, France
| | - P Fossati
- Control-Interoception-Attention team, Paris Brain Institute, Institut du Cerveau (ICM), UMR 7225/UMR_S 1127, Sorbonne University/CNRS/Inserm, Paris, France.; Department of Psychiatry, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris (APHP), Paris, France
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6
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Karlov DS, Radchenko EV, Palyulin VA, Zefirov NS. Molecular design of proneurogenic and neuroprotective compounds-allosteric NMDA receptor modulators. DOKL BIOCHEM BIOPHYS 2017; 473:132-136. [PMID: 28510125 DOI: 10.1134/s1607672917020119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Indexed: 01/23/2023]
Abstract
N-Methyl-D-aspartic acid (NMDA) receptor is a promising target for treatment of neurodegenerative diseases and other brain disorders as well as for designing proneurogenic compounds able to stimulate neurogenesis in adult brain. We analyzed the structure of the binding site of negative allosteric modulators in the amino-terminal domain of the NMDA receptor and identified possible modes of their binding as well as performed molecular design of new modulators that significantly differ from the known ones in structure and binding mode. In addition, we formed a focused library of chemical compounds with potential neuroprotective and proneurogenic properties, desirable set of pharmacokinetic properties, and low toxicity, which can be the basis for development of new-generation drugs.
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Affiliation(s)
- D S Karlov
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia.,Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Moscow oblast, 142432, Russia
| | - E V Radchenko
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia. .,Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Moscow oblast, 142432, Russia.
| | - V A Palyulin
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia.,Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Moscow oblast, 142432, Russia
| | - N S Zefirov
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russia.,Institute of Physiologically Active Compounds, Russian Academy of Sciences, Chernogolovka, Moscow oblast, 142432, Russia
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7
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Ravi N, Sanchez-Guardado L, Lois C, Kelsch W. Determination of the connectivity of newborn neurons in mammalian olfactory circuits. Cell Mol Life Sci 2017; 74:849-867. [PMID: 27695873 PMCID: PMC11107630 DOI: 10.1007/s00018-016-2367-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 08/24/2016] [Accepted: 09/13/2016] [Indexed: 12/24/2022]
Abstract
The mammalian olfactory bulb is a forebrain structure just one synapse downstream from the olfactory sensory neurons and performs the complex computations of sensory inputs. The formation of this sensory circuit is shaped through activity-dependent and cell-intrinsic mechanisms. Recent studies have revealed that cell-type specific connectivity and the organization of synapses in dendritic compartments are determined through cell-intrinsic programs already preset in progenitor cells. These progenitor programs give rise to subpopulations within a neuron type that have distinct synaptic organizations. The intrinsically determined formation of distinct synaptic organizations requires factors from contacting cells that match the cell-intrinsic programs. While certain genes control wiring within the newly generated neurons, other regulatory genes provide intercellular signals and are only expressed in neurons that will form contacts with the newly generated cells. Here, the olfactory system has provided a useful model circuit to reveal the factors regulating assembly of the highly structured connectivity in mammals.
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Affiliation(s)
- Namasivayam Ravi
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Luis Sanchez-Guardado
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA, 91125, USA
| | - Carlos Lois
- Division of Biology and Biological Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA, 91125, USA.
| | - Wolfgang Kelsch
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany.
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Yun S, Reynolds RP, Masiulis I, Eisch AJ. Re-evaluating the link between neuropsychiatric disorders and dysregulated adult neurogenesis. Nat Med 2016; 22:1239-1247. [PMID: 27783068 PMCID: PMC5791154 DOI: 10.1038/nm.4218] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 09/30/2016] [Indexed: 12/11/2022]
Abstract
People diagnosed with neuropsychiatric disorders such as depression, anxiety, addiction or schizophrenia often have dysregulated memory, mood, pattern separation and/or reward processing. These symptoms are indicative of a disrupted function of the dentate gyrus (DG) subregion of the brain, and they improve with treatment and remission. The dysfunction of the DG is accompanied by structural maladaptations, including dysregulation of adult-generated neurons. An increasing number of studies using modern inducible approaches to manipulate new neurons show that the behavioral symptoms in animal models of neuropsychiatric disorders can be produced or exacerbated by the inhibition of DG neurogenesis. Thus, here we posit that the connection between neuropsychiatric disorders and dysregulated DG neurogenesis is beyond correlation or epiphenomenon, and that the regulation of adult-generated DG neurogenesis merits continued and focused attention in the ongoing effort to develop novel treatments for neuropsychiatric disorders.
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Affiliation(s)
- Sanghee Yun
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ryan P Reynolds
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Irene Masiulis
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Amelia J Eisch
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Neuroscience and Mahoney Institute of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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9
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Jin X. The role of neurogenesis during development and in the adult brain. Eur J Neurosci 2016; 44:2291-9. [DOI: 10.1111/ejn.13251] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 04/05/2016] [Accepted: 04/05/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Xing Jin
- Department of Pharmacy; the Affiliated Suzhou Municipal Hospital; Nanjing Medical University; Suzhou 215001 China
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10
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Mu Y, Zhao C, Toni N, Yao J, Gage FH. Distinct roles of NMDA receptors at different stages of granule cell development in the adult brain. eLife 2015; 4:e07871. [PMID: 26473971 PMCID: PMC4608052 DOI: 10.7554/elife.07871] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 09/12/2015] [Indexed: 12/01/2022] Open
Abstract
NMDA receptor (NMDAR)-dependent forms of synaptic plasticity are thought to underlie the assembly of developing neuronal circuits and to play a crucial role in learning and memory. It remains unclear how NMDAR might contribute to the wiring of adult-born granule cells (GCs). Here we demonstrate that nascent GCs lacking NMDARs but rescued from apoptosis by overexpressing the pro-survival protein Bcl2 were deficient in spine formation. Insufficient spinogenesis might be a general cause of cell death restricted within the NMDAR-dependent critical time window for GC survival. NMDAR loss also led to enhanced mushroom spine formation and synaptic AMPAR activity throughout the development of newborn GCs. Moreover, similar elevated synapse maturation in the absence of NMDARs was observed in neonate-generated GCs and CA1 pyramidal neurons. Together, these data suggest that NMDAR operates as a molecular monitor for controlling the activity-dependent establishment and maturation rate of synaptic connections between newborn neurons and others. DOI:http://dx.doi.org/10.7554/eLife.07871.001 The brain contains billions of cells called neurons. Although most neurons have already formed by the time we are born, part of the brain called the hippocampus produces new neurons throughout our life. These new neurons are thought to be important for learning and forming new memories. Neurons send signals to each other across connections called synapses. Small protrusions called spines stick out of the neuron and each tends to have one synapse that receives a signal from another neuron. Via these connections, the neurons are organized into networks and circuits that control how different parts of the brain work. Therefore, once new neurons are made, they also need to be connected to the correct neurons. The NMDA receptor is found in the surface of neurons, and mutated neurons that lack this receptor often die shortly after birth. The NMDA receptor is also known to be important for organizing synapses. Exactly how NMDA receptors help new neurons to survive and integrate into circuits has not been investigated in detail. Mu, Zhao et al. now address this issue by using mice in which a gene called NR1, which produces one of the proteins that makes up the NMDA receptor, can be deleted at specific stages of neuron development. Analyzing brain slices from the mice showed that deleting NR1 from newly-formed neurons caused them to die within two or three weeks. When these neurons were forced to survive, they had fewer spines than normal. By contrast, deleting NR1 from neurons that has already survived for longer than four weeks did not alter how many spines the neurons had. Instead, the synapses on the spines worked better. Mu, Zhao et al. therefore suggest that NMDA receptors have different roles at different stages of a neuron's development. Initially, NMDA receptors help the neurons to survive and form spines. The receptors then help to ensure the spines become the correct size, and enable the neurons to connect into the right neural circuits by helping to control the strength of synapses. Mu, Zhao et al. theorize that the mere presence of NMDA receptors suppresses spine maturation. Furthermore, this inhibitory effect is only released when the NMDA receptor is activated, or when the NMDA receptor is absent due to the deletion of the NR1 gene. Further studies will be needed to validate this hypothesis. DOI:http://dx.doi.org/10.7554/eLife.07871.002
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Affiliation(s)
- Yangling Mu
- Department of Physiology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China.,Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China
| | - Chunmei Zhao
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, United States
| | - Nicolas Toni
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Jun Yao
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Fred H Gage
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, United States
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GluN2B-containing NMDA receptors promote glutamate synapse development in hippocampal interneurons. J Neurosci 2015; 34:16022-30. [PMID: 25429143 DOI: 10.1523/jneurosci.1210-14.2014] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In postnatal development, GluN2B-containing NMDARs are critical for the functional maturation of glutamatergic synapses. GluN2B-containing NMDARs prevail until the second postnatal week when GluN2A subunits are progressively added, conferring mature properties to NMDARs. In cortical principal neurons, deletion of GluN2B results in an increase in functional AMPAR synapses, suggesting that GluN2B-containing NMDARs set a brake on glutamate synapse maturation. The function of GluN2B in the maturation of glutamatergic inputs to cortical interneurons is not known. To examine the function of GluN2B in interneurons, we generated mutant mice with conditional deletion of GluN2B in interneurons (GluN2B(ΔGAD67)). In GluN2B(ΔGAD67) mice interneurons distributed normally in cortical brain regions. After the second postnatal week, GluN2B(ΔGAD67) mice developed hippocampal seizures and died shortly thereafter. Before the onset of seizures, GluN2B-deficient hippocampal interneurons received fewer glutamatergic synaptic inputs than littermate controls, indicating that GluN2B-containing NMDARs positively regulate the maturation of glutamatergic input synapses in interneurons. These findings suggest that GluN2B-containing NMDARs keep the circuit activity under control by promoting the maturation of excitatory synapses in interneurons.
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12
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Pallotto M, Deprez F. Regulation of adult neurogenesis by GABAergic transmission: signaling beyond GABAA-receptors. Front Cell Neurosci 2014; 8:166. [PMID: 24999317 PMCID: PMC4064292 DOI: 10.3389/fncel.2014.00166] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 06/02/2014] [Indexed: 01/09/2023] Open
Abstract
In the adult mammalian brain, neurogenesis occurs in the olfactory bulb (OB) and in the dentate gyrus (DG) of the hippocampus. Several studies have shown that multiple stages of neurogenesis are regulated by GABAergic transmission with precise spatio-temporal selectivity, and involving mechanisms common to both systems or specific only to one. In the subgranular zone (SGZ) of the DG, GABA neurotransmitter, released by a specific population of interneurons, regulates stem cell quiescence and neuronal cell fate decisions. Similarly, in the subventricular zone (SVZ), OB neuroblast production is modulated by ambient GABA. Ambient GABA, acting on extrasynaptic GABAA receptors (GABAAR), is also crucial for proper adult-born granule cell (GC) maturation and synaptic integration in the OB as well as in the DG. Throughout adult-born neuron development, various GABA receptors and receptor subunits play specific roles. Previous work has demonstrated that adult-born GCs in both the OB and the DG show a time window of increased plasticity in which adult-born cells are more prone to modification by external stimuli. One mechanism that controls this "critical period" is GABAergic modulation. Indeed, depleting the main phasic GABAergic inputs in adult-born neurons results in dramatic effects, such as reduction of spine density and dendritic branching in adult-born OB GCs. In this review, we systematically compare the role of GABAergic transmission in the regulation of adult neurogenesis between the OB and the hippocampus, focusing on the role of GABA in modulating plasticity and critical periods of adult-born neuron development. Finally, we discuss signaling pathways that might mediate some of the deficits observed upon targeted deletion of postsynaptic GABAARs in adult-born neurons.
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Affiliation(s)
- Marta Pallotto
- Circuit Dynamics and Connectivity Unit, National Institute Neurological Disorders and Stroke, National Institute of Health Bethesda, MD, USA
| | - Francine Deprez
- Neuroscience Center Zurich, Institute of Pharmacology and Toxicology, University of Zurich Zurich, Switzerland
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13
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Schmidt-Salzmann C, Li L, Bischofberger J. Functional properties of extrasynaptic AMPA and NMDA receptors during postnatal hippocampal neurogenesis. J Physiol 2013; 592:125-40. [PMID: 24218546 DOI: 10.1113/jphysiol.2013.267203] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In the mammalian hippocampus, new granule cells are continuously generated throughout life. Although it is well known that they rapidly form several thousand new glutamatergic synapses, the underlying mechanisms are not well understood. As extrasynaptic NMDA receptors are believed to support the generation of new spines, we have studied the functional properties of extrasynaptic ionotropic glutamate receptors in newborn granule cells in juvenile rats during and after synaptic integration. Using the fast application of glutamate to outside-out membrane patches, we show that all immature granule cells express functional AMPA and NMDA receptors. The density of AMPA receptors was small in cells starting to receive excitatory synaptic input (∼30 pS μm(-2)) but substantially increased during synaptic integration to finally reach ∼120 pS μm(-2) in fully mature cells. Interestingly, AMPA receptors showed a biphasic change in desensitization time constant which was slowest during synaptic integration and substantially faster before and afterwards. This was paralleled by a change in the non-desensitizing current component which was maximal during synaptic integration and about 50% smaller afterwards. Surprisingly, the NMDA receptor kinetics and density in young cells was already comparable to mature cells (∼10 pS μm(-2)), leading to an enhanced NMDA/AMPA receptor density ratio. Similar to somatic outside-out patches, iontophoretic application of glutamate onto dendrites also revealed an enhanced dendritic NMDA/AMPA ratio in young cells. These data indicate that prolonged AMPA receptor currents in newly generated young granule cells might support the effective activation of extrasynaptic NMDA receptors and therefore constitute a competitive advantage over mature cells for new synapse formation.
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Affiliation(s)
- Charlotte Schmidt-Salzmann
- J. Bischofberger: Department of Biomedicine, Physiological Institute, University of Basel, Pestalozzistr. 20, CH-4056 Basel, Switzerland.
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