1
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Pál B. On the functions of astrocyte-mediated neuronal slow inward currents. Neural Regen Res 2024; 19:2602-2612. [PMID: 38595279 DOI: 10.4103/nrr.nrr-d-23-01723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/24/2024] [Indexed: 04/11/2024] Open
Abstract
Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extrasynaptic N-methyl-D-aspartate receptors with the contribution of astrocytes. These events are significantly slower than the excitatory postsynaptic currents. Parameters of slow inward currents are determined by several factors including the mechanisms of astrocytic activation and glutamate release, as well as the diffusion pathways from the release site towards the extrasynaptic receptors. Astrocytes are stimulated by neuronal network activity, which in turn excite neurons, forming an astrocyte-neuron feedback loop. Mostly as a consequence of brain edema, astrocytic swelling can also induce slow inward currents under pathological conditions. There is a growing body of evidence on the roles of slow inward currents on a single neuron or local network level. These events often occur in synchrony on neurons located in the same astrocytic domain. Besides synchronization of neuronal excitability, slow inward currents also set synaptic strength via eliciting timing-dependent synaptic plasticity. In addition, slow inward currents are also subject to non-synaptic plasticity triggered by long-lasting stimulation of the excitatory inputs. Of note, there might be important region-specific differences in the roles and actions triggering slow inward currents. In greater networks, the pathophysiological roles of slow inward currents can be better understood than physiological ones. Slow inward currents are identified in the pathophysiological background of autism, as slow inward currents drive early hypersynchrony of the neural networks. Slow inward currents are significant contributors to paroxysmal depolarizational shifts/interictal spikes. These events are related to epilepsy, but also found in Alzheimer's disease, Parkinson's disease, and stroke, leading to the decline of cognitive functions. Events with features overlapping with slow inward currents (excitatory, N-methyl-D-aspartate-receptor mediated currents with astrocytic contribution) as ischemic currents and spreading depolarization also have a well-known pathophysiological role in worsening consequences of stroke, traumatic brain injury, or epilepsy. One might assume that slow inward currents occurring with low frequency under physiological conditions might contribute to synaptic plasticity and memory formation. However, to state this, more experimental evidence from greater neuronal networks or the level of the individual is needed. In this review, I aimed to summarize findings on slow inward currents and to speculate on the potential functions of it.
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Affiliation(s)
- Balázs Pál
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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2
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Weber FB, Santos CL, da Silva A, Schmitz I, Rezena E, Gonçalves CA, Quincozes-Santos A, Bobermin LD. Differences between cultured astrocytes from neonatal and adult Wistar rats: focus on in vitro aging experimental models. In Vitro Cell Dev Biol Anim 2024; 60:420-431. [PMID: 38546817 DOI: 10.1007/s11626-024-00896-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 03/07/2024] [Indexed: 05/07/2024]
Abstract
Astrocytes play key roles regulating brain homeostasis and accumulating evidence has suggested that glia are the first cells that undergo functional changes with aging, which can lead to a decline in brain function. In this context, in vitro models are relevant tools for studying aged astrocytes and, here, we investigated functional and molecular changes in cultured astrocytes obtained from neonatal or adult animals submitted to an in vitro model of aging by an additional period of cultivation of cells after confluence. In vitro aging induced different metabolic effects regarding glucose and glutamate uptake, as well as glutamine synthetase activity, in astrocytes obtained from adult animals compared to those obtained from neonatal animals. In vitro aging also modulated glutathione-related antioxidant defenses and increased reactive oxygen species and cytokine release especially in astrocytes from adult animals. Interestingly, in vitro aged astrocytes from adult animals exposed to pro-oxidant, inflammatory, and antioxidant stimuli showed enhanced oxidative and inflammatory responses. Moreover, these functional changes were correlated with the expression of the senescence marker p21, cytoskeleton markers, glutamate transporters, inflammatory mediators, and signaling pathways such as nuclear factor κB (NFκB)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1). Alterations in these genes are remarkably associated with a potential neurotoxic astrocyte phenotype. Therefore, considering the experimental limitations due to the need for long-term maintenance of the animals for studying aging, astrocyte cultures obtained from adult animals further aged in vitro can provide an improved experimental model for understanding the mechanisms associated with aging-related astrocyte dysfunction.
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Affiliation(s)
- Fernanda Becker Weber
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Camila Leite Santos
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Amanda da Silva
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Izaviany Schmitz
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Ester Rezena
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Carlos-Alberto Gonçalves
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
- Programa de Pós-Graduação Em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Ramiro Barcelos, 2600, Porto Alegre, RS, 90035-003, Brazil
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - André Quincozes-Santos
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
- Programa de Pós-Graduação Em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Ramiro Barcelos, 2600, Porto Alegre, RS, 90035-003, Brazil
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Larissa Daniele Bobermin
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil.
- Programa de Pós-Graduação Em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Ramiro Barcelos, 2600, Porto Alegre, RS, 90035-003, Brazil.
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3
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Tsai YC, Huang SM, Peng HH, Lin SW, Lin SR, Chin TY, Huang SM. Imbalance of synaptic and extrasynaptic NMDA receptors induced by the deletion of CRMP1 accelerates age-related cognitive decline in mice. Neurobiol Aging 2024; 135:48-59. [PMID: 38176125 DOI: 10.1016/j.neurobiolaging.2023.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 12/25/2023] [Accepted: 12/27/2023] [Indexed: 01/06/2024]
Abstract
Collapsin response mediator protein 1 (CRMP1) is involved in semaphorin 3A signaling pathway, promoting neurite extension and growth cone collapse. It is highly expressed in the nervous system, especially the hippocampus. The crmp1 knockout (KO) mice display impaired spatial learning and memory, and this phenomenon seemingly tends to deteriorate with age. Here we investigated whether CRMP1 is involved in age-related cognitive decline in WT and crmp1 KO mice at adult, middle-aged and older stages. The results revealed that cognitive dysfunction in the Morris water maze task became more severe and decreased glutamate and glutamine level in middle-aged crmp1 KO mice. Additionally, increasing levels of extrasynaptic NMDA receptors and phosphorylation of Tau were observed in middle-aged crmp1 KO mice, leading to synaptic and neuronal loss in the CA3 regions of hippocampus. These findings suggest that deletion of CRMP1 accelerates age-related cognitive decline by disrupting the balance between synaptic and extrasynaptic NMDA receptors, resulting in the loss of synapses and neurons.
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Affiliation(s)
- Yun-Chieh Tsai
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Sheng-Min Huang
- Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan
| | - Hsu-Hsia Peng
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Shu-Wha Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Shu-Rung Lin
- Department of Bioscience Technology, Chung Yuan Christian University, Taoyuan, Taiwan.
| | - Ting-Yu Chin
- Department of Bioscience Technology, Chung Yuan Christian University, Taoyuan, Taiwan.
| | - Shih-Ming Huang
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan; Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan.
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4
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Vazquez-Juarez E, Srivastava I, Lindskog M. The effect of ketamine on synaptic mistuning induced by impaired glutamate reuptake. Neuropsychopharmacology 2023; 48:1859-1868. [PMID: 37301901 PMCID: PMC10584870 DOI: 10.1038/s41386-023-01617-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 05/05/2023] [Accepted: 05/19/2023] [Indexed: 06/12/2023]
Abstract
Mistuning of synaptic transmission has been proposed to underlie many psychiatric disorders, with decreased reuptake of the excitatory neurotransmitter glutamate as one contributing factor. Synaptic tuning occurs through several diverging and converging forms of plasticity. By recording evoked field postsynaptic potentials in the CA1 area in hippocampal slices, we found that inhibiting glutamate transporters using DL-TBOA causes retuning of synaptic transmission, resulting in a new steady state with reduced synaptic strength and a lower threshold for inducing long-term synaptic potentiation (LTP). Moreover, a similar reduced threshold for LTP was observed in a rat model of depression with decreased levels of glutamate transporters. Most importantly, we found that the antidepressant ketamine counteracts the effects of increased glutamate on the various steps involved in synaptic retuning. We, therefore, propose that ketamine's mechanism of action as an antidepressant is to restore adequate synaptic tuning.
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Affiliation(s)
- Erika Vazquez-Juarez
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Ipsit Srivastava
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, 171 77, Stockholm, Sweden
- Department of Medical Cell Biology, Uppsala University, 751 24, Uppsala, Sweden
| | - Maria Lindskog
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, 171 77, Stockholm, Sweden.
- Department of Medical Cell Biology, Uppsala University, 751 24, Uppsala, Sweden.
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5
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Ladagu AD, Olopade FE, Adejare A, Olopade JO. GluN2A and GluN2B N-Methyl-D-Aspartate Receptor (NMDARs) Subunits: Their Roles and Therapeutic Antagonists in Neurological Diseases. Pharmaceuticals (Basel) 2023; 16:1535. [PMID: 38004401 PMCID: PMC10674917 DOI: 10.3390/ph16111535] [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: 09/08/2023] [Revised: 10/11/2023] [Accepted: 10/27/2023] [Indexed: 11/26/2023] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs) are ion channels that respond to the neurotransmitter glutamate, playing a crucial role in the permeability of calcium ions and excitatory neurotransmission in the central nervous system (CNS). Composed of various subunits, NMDARs are predominantly formed by two obligatory GluN1 subunits (with eight splice variants) along with regulatory subunits GluN2 (GluN2A-2D) and GluN3 (GluN3A-B). They are widely distributed throughout the CNS and are involved in essential functions such as synaptic transmission, learning, memory, plasticity, and excitotoxicity. The presence of GluN2A and GluN2B subunits is particularly important for cognitive processes and has been strongly implicated in neurodegenerative diseases like Parkinson's disease and Alzheimer's disease. Understanding the roles of GluN2A and GluN2B NMDARs in neuropathologies provides valuable insights into the underlying causes and complexities of major nervous system disorders. This knowledge is vital for the development of selective antagonists targeting GluN2A and GluN2B subunits using pharmacological and molecular methods. Such antagonists represent a promising class of NMDA receptor inhibitors that have the potential to be developed into neuroprotective drugs with optimal therapeutic profiles.
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Affiliation(s)
- Amany Digal Ladagu
- Department of Veterinary Anatomy, University of Ibadan, Ibadan 200284, Nigeria; (A.D.L.); (J.O.O.)
| | - Funmilayo Eniola Olopade
- Developmental Neurobiology Laboratory, Department of Anatomy, College of Medicine, University of Ibadan, Ibadan 200284, Nigeria
| | - Adeboye Adejare
- Department of Pharmaceutical Sciences, Philadelphia College of Pharmacy, Saint Joseph’s University, Philadelphia, PA 19131, USA
| | - James Olukayode Olopade
- Department of Veterinary Anatomy, University of Ibadan, Ibadan 200284, Nigeria; (A.D.L.); (J.O.O.)
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6
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Pinky PD, Bloemer J, Smith WD, Du Y, Heslin RT, Setti SE, Pfitzer JC, Chowdhury K, Hong H, Bhattacharya S, Dhanasekaran M, Dityatev A, Reed MN, Suppiramaniam V. Prenatal Cannabinoid Exposure Elicits Memory Deficits Associated with Reduced PSA-NCAM Expression, Altered Glutamatergic Signaling, and Adaptations in Hippocampal Synaptic Plasticity. Cells 2023; 12:2525. [PMID: 37947603 PMCID: PMC10648717 DOI: 10.3390/cells12212525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 10/02/2023] [Accepted: 10/06/2023] [Indexed: 11/12/2023] Open
Abstract
Cannabis is now one of the most commonly used illicit substances among pregnant women. This is particularly concerning since developmental exposure to cannabinoids can elicit enduring neurofunctional and cognitive alterations. This study investigates the mechanisms of learning and memory deficits resulting from prenatal cannabinoid exposure (PCE) in adolescent offspring. The synthetic cannabinoid agonist WIN55,212-2 was administered to pregnant rats, and a series of behavioral, electrophysiological, and immunochemical studies were performed to identify potential mechanisms of memory deficits in the adolescent offspring. Hippocampal-dependent memory deficits in adolescent PCE animals were associated with decreased long-term potentiation (LTP) and enhanced long-term depression (LTD) at hippocampal Schaffer collateral-CA1 synapses, as well as an imbalance between GluN2A- and GluN2B-mediated signaling. Moreover, PCE reduced gene and protein expression of neural cell adhesion molecule (NCAM) and polysialylated-NCAM (PSA-NCAM), which are critical for GluN2A and GluN2B signaling balance. Administration of exogenous PSA abrogated the LTP deficits observed in PCE animals, suggesting PSA mediated alterations in GluN2A- and GluN2B- signaling pathways may be responsible for the impaired hippocampal synaptic plasticity resulting from PCE. These findings enhance our current understanding of how PCE affects memory and how this process can be manipulated for future therapeutic purposes.
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Affiliation(s)
- Priyanka D. Pinky
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36849, USA
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92697, USA
| | - Jenna Bloemer
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36849, USA
- Department of Pharmaceutical and Biomedical Sciences, Touro College of Pharmacy, New York, NY 10036, USA
| | - Warren D. Smith
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36849, USA
| | - Yifeng Du
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36849, USA
| | - Ryan T. Heslin
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36849, USA
| | - Sharay E. Setti
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36849, USA
| | - Jeremiah C. Pfitzer
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36849, USA
| | - Kawsar Chowdhury
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36849, USA
| | - Hao Hong
- Key Laboratory of Neuropsychiatric Diseases, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, and State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China
| | - Subhrajit Bhattacharya
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36849, USA
- Center for Neuroscience Initiative, Auburn University, Auburn, AL 36849, USA
- Keck Graduate Institute, School of Pharmacy and Health Sciences, Claremont Colleges, Claremont, CA 91711, USA
| | - Muralikrishnan Dhanasekaran
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36849, USA
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 37075 Magdeburg, Germany
| | - Alexander Dityatev
- Center for Neuroscience Initiative, Auburn University, Auburn, AL 36849, USA
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 37075 Magdeburg, Germany
- Medical Faculty, Otto-von-Guericke University, 39106 Magdeburg, Germany
| | - Miranda N. Reed
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36849, USA
- Center for Neuroscience Initiative, Auburn University, Auburn, AL 36849, USA
| | - Vishnu Suppiramaniam
- Department of Drug Discovery and Development, Auburn University, Auburn, AL 36849, USA
- Center for Neuroscience Initiative, Auburn University, Auburn, AL 36849, USA
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7
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Verkhratsky A, Butt A, Li B, Illes P, Zorec R, Semyanov A, Tang Y, Sofroniew MV. Astrocytes in human central nervous system diseases: a frontier for new therapies. Signal Transduct Target Ther 2023; 8:396. [PMID: 37828019 PMCID: PMC10570367 DOI: 10.1038/s41392-023-01628-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 08/15/2023] [Accepted: 08/22/2023] [Indexed: 10/14/2023] Open
Abstract
Astroglia are a broad class of neural parenchymal cells primarily dedicated to homoeostasis and defence of the central nervous system (CNS). Astroglia contribute to the pathophysiology of all neurological and neuropsychiatric disorders in ways that can be either beneficial or detrimental to disorder outcome. Pathophysiological changes in astroglia can be primary or secondary and can result in gain or loss of functions. Astroglia respond to external, non-cell autonomous signals associated with any form of CNS pathology by undergoing complex and variable changes in their structure, molecular expression, and function. In addition, internally driven, cell autonomous changes of astroglial innate properties can lead to CNS pathologies. Astroglial pathophysiology is complex, with different pathophysiological cell states and cell phenotypes that are context-specific and vary with disorder, disorder-stage, comorbidities, age, and sex. Here, we classify astroglial pathophysiology into (i) reactive astrogliosis, (ii) astroglial atrophy with loss of function, (iii) astroglial degeneration and death, and (iv) astrocytopathies characterised by aberrant forms that drive disease. We review astroglial pathophysiology across the spectrum of human CNS diseases and disorders, including neurotrauma, stroke, neuroinfection, autoimmune attack and epilepsy, as well as neurodevelopmental, neurodegenerative, metabolic and neuropsychiatric disorders. Characterising cellular and molecular mechanisms of astroglial pathophysiology represents a new frontier to identify novel therapeutic strategies.
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Affiliation(s)
- Alexei Verkhratsky
- International Joint Research Centre on Purinergic Signalling/School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, China.
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China.
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
- Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102, Vilnius, Lithuania.
| | - Arthur Butt
- Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
| | - Baoman Li
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China
| | - Peter Illes
- International Joint Research Centre on Purinergic Signalling/School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, China
- Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, 04109, Leipzig, Germany
| | - Robert Zorec
- Celica Biomedical, Lab Cell Engineering, Technology Park, 1000, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, University of Ljubljana, Faculty of Medicine, Ljubljana, Slovenia
| | - Alexey Semyanov
- Department of Physiology, Jiaxing University College of Medicine, 314033, Jiaxing, China
| | - Yong Tang
- International Joint Research Centre on Purinergic Signalling/School of Health and Rehabilitation, Chengdu University of Traditional Chinese Medicine, Chengdu, China.
- Key Laboratory of Acupuncture for Senile Disease (Chengdu University of TCM), Ministry of Education/Acupuncture and Chronobiology Key Laboratory of Sichuan Province, Chengdu, China.
| | - Michael V Sofroniew
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
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8
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Matias I, Diniz LP, Araujo APB, Damico IV, de Moura P, Cabral-Miranda F, Diniz F, Parmeggiani B, de Mello Coelho V, Leite REP, Suemoto CK, Ferreira GC, Kubrusly RCC, Gomes FCA. Age-Associated Upregulation of Glutamate Transporters and Glutamine Synthetase in Senescent Astrocytes In Vitro and in the Mouse and Human Hippocampus. ASN Neuro 2023; 15:17590914231157974. [PMID: 36815213 PMCID: PMC9950616 DOI: 10.1177/17590914231157974] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023] Open
Abstract
Aging is marked by complex and progressive physiological changes, including in the glutamatergic system, that lead to a decline of brain function. Increased content of senescent cells in the brain, such as glial cells, has been reported to impact cognition both in animal models and human tissue during normal aging and in the context of neurodegenerative disease. Changes in the glutamatergic synaptic activity rely on the glutamate-glutamine cycle, in which astrocytes handle glutamate taken up from synapses and provide glutamine for neurons, thus maintaining excitatory neurotransmission. However, the mechanisms of glutamate homeostasis in brain aging are still poorly understood. Herein, we showed that mouse senescent astrocytes in vitro undergo upregulation of GLT-1, GLAST, and glutamine synthetase (GS), along with the increased enzymatic activity of GS and [3H]-D-aspartate uptake. Furthermore, we observed higher levels of GS and increased [3H]-D-aspartate uptake in the hippocampus of aged mice, although the activity of GS was similar between young and old mice. Analysis of a previously available RNAseq dataset of mice at different ages revealed upregulation of GLAST and GS mRNA levels in hippocampal astrocytes during aging. Corroborating these rodent data, we showed an increased number of GS + cells, and GS and GLT-1 levels/intensity in the hippocampus of elderly humans. Our data suggest that aged astrocytes undergo molecular and functional changes that control glutamate-glutamine homeostasis upon brain aging.
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Affiliation(s)
- Isadora Matias
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de
Janeiro, Rio de Janeiro, Brasil, Isadora Matias, Instituto de Ciências
Biomédicas, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde,
Bloco F, Ilha do Fundão, 21941-902 - Rio de Janeiro, RJ, Brasil.
| | - Luan Pereira Diniz
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de
Janeiro, Rio de Janeiro, Brasil
| | - Ana Paula Bergamo Araujo
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de
Janeiro, Rio de Janeiro, Brasil
| | - Isabella Vivarini Damico
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de
Janeiro, Rio de Janeiro, Brasil
| | - Pâmella de Moura
- Instituto Biomédico, Universidade Federal
Fluminense, Niterói, Brasil
| | - Felipe Cabral-Miranda
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de
Janeiro, Rio de Janeiro, Brasil
| | - Fabiola Diniz
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de
Janeiro, Rio de Janeiro, Brasil,Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de
Janeiro, Rio de Janeiro, Brasil
| | - Belisa Parmeggiani
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de
Janeiro, Rio de Janeiro, Brasil
| | - Valeria de Mello Coelho
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de
Janeiro, Rio de Janeiro, Brasil
| | - Renata E. P. Leite
- Biobanco para Estudos em Envelhecimento, Faculdade de Medicina da Universidade de
São Paulo, São Paulo, Brasil,Divisão de Geriatria, Faculdade de Medicina da Universidade de São
Paulo, São Paulo, Brasil
| | - Claudia K. Suemoto
- Divisão de Geriatria, Faculdade de Medicina da Universidade de São
Paulo, São Paulo, Brasil
| | - Gustavo Costa Ferreira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de
Janeiro, Rio de Janeiro, Brasil
| | | | - Flávia Carvalho Alcantara Gomes
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de
Janeiro, Rio de Janeiro, Brasil,Flávia Carvalho Alcantara Gomes. Instituto
de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Centro de
Ciências da Saúde, Bloco F, Ilha do Fundão, 21941-902 - Rio de Janeiro, RJ,
Brasil.
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9
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Verkhratsky A, Semyanov A. Astrocytes in Ageing. Subcell Biochem 2023; 103:253-277. [PMID: 37120471 DOI: 10.1007/978-3-031-26576-1_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Ageing is associated with a morphological and functional decline of astrocytes with a prevalence of morphological atrophy and loss of function. In particular, ageing is manifested by the shrinkage of astrocytic processes: branches and leaflets, which decreases synaptic coverage. Astrocytic dystrophy affects multiple functions astrocytes play in the brain active milieu. In particular, and in combination with an age-dependent decline in the expression of glutamate transporters, astrocytic atrophy translates into deficient glutamate clearance and K+ buffering. Decreased astrocyte presence may contribute to age-dependent remodelling of brain extracellular space, hence affecting extrasynaptic signalling. Old astrocytes lose endfeet polarisation of AQP4 water channels, thus limiting the operation of the glymphatic system. In ageing, astrocytes down-regulate their antioxidant capacity leading to decreased neuroprotection. All these changes may contribute to an age-dependent cognitive decline.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
- Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
- Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain.
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China.
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania.
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- Sechenov First Moscow State Medical University, Moscow, Russia
- Department of Physiology, Jiaxing University College of Medicine, Jiaxing, Zhejiang Pro, China
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10
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Hu Z, Ondrejcak T, Yu P, Zhang Y, Yang Y, Klyubin I, Kennelly SP, Rowan MJ, Hu NW. Do tau-synaptic long-term depression interactions in the hippocampus play a pivotal role in the progression of Alzheimer's disease? Neural Regen Res 2022; 18:1213-1219. [PMID: 36453396 PMCID: PMC9838152 DOI: 10.4103/1673-5374.360166] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Cognitive decline in Alzheimer's disease correlates with the extent of tau pathology, in particular tau hyperphosphorylation that initially appears in the transentorhinal and related regions of the brain including the hippocampus. Recent evidence indicates that tau hyperphosphorylation caused by either amyloid-β or long-term depression, a form of synaptic weakening involved in learning and memory, share similar mechanisms. Studies from our group and others demonstrate that long-term depression-inducing low-frequency stimulation triggers tau phosphorylation at different residues in the hippocampus under different experimental conditions including aging. Conversely, certain forms of long-term depression at hippocampal glutamatergic synapses require endogenous tau, in particular, phosphorylation at residue Ser396. Elucidating the exact mechanisms of interaction between tau and long-term depression may help our understanding of the physiological and pathological functions of tau/tau (hyper)phosphorylation. We first summarize experimental evidence regarding tau-long-term depression interactions, followed by a discussion of possible mechanisms by which this interplay may influence the pathogenesis of Alzheimer's disease. Finally, we conclude with some thoughts and perspectives on future research about these interactions.
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Affiliation(s)
- Zhengtao Hu
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan Province, China,Department of Gerontology, The First Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
| | - Tomas Ondrejcak
- Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Pengpeng Yu
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan Province, China
| | - Yangyang Zhang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan Province, China
| | - Yin Yang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan Province, China,Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Igor Klyubin
- Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Sean P. Kennelly
- Department of Age-Related Healthcare, Tallaght University Hospital, Dublin, Ireland,Department of Medical Gerontology, Trinity College, Dublin, Ireland
| | - Michael J. Rowan
- Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Neng-Wei Hu
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan Province, China,Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland,Correspondence to: Neng-Wei Hu, .
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11
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Andersen JV, Schousboe A, Verkhratsky A. Astrocyte energy and neurotransmitter metabolism in Alzheimer's disease: integration of the glutamate/GABA-glutamine cycle. Prog Neurobiol 2022; 217:102331. [PMID: 35872221 DOI: 10.1016/j.pneurobio.2022.102331] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/14/2022] [Accepted: 07/19/2022] [Indexed: 02/06/2023]
Abstract
Astrocytes contribute to the complex cellular pathology of Alzheimer's disease (AD). Neurons and astrocytes function in close collaboration through neurotransmitter recycling, collectively known as the glutamate/GABA-glutamine cycle, which is essential to sustain neurotransmission. Neurotransmitter recycling is intimately linked to astrocyte energy metabolism. In the course of AD, astrocytes undergo extensive metabolic remodeling, which may profoundly affect the glutamate/GABA-glutamine cycle. The consequences of altered astrocyte function and metabolism in relation to neurotransmitter recycling are yet to be comprehended. Metabolic alterations of astrocytes in AD deprive neurons of metabolic support, thereby contributing to synaptic dysfunction and neurodegeneration. In addition, several astrocyte-specific components of the glutamate/GABA-glutamine cycle, including glutamine synthesis and synaptic neurotransmitter uptake, are perturbed in AD. Integration of the complex astrocyte biology within the context of AD is essential for understanding the fundamental mechanisms of the disease, while restoring astrocyte metabolism may serve as an approach to arrest or even revert clinical progression of AD.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK; Achucarro Center for Neuroscience, IKERBASQUE, 48011 Bilbao, Spain; Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102 Vilnius, Lithuania.
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12
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Zhang Y, Yang Y, Hu Z, Zhu M, Qin S, Yu P, Li B, Xu J, Ondrejcak T, Klyubin I, Rowan MJ, Hu NW. Long-Term Depression-Inducing Low Frequency Stimulation Enhances p-Tau181 and p-Tau217 in an Age-Dependent Manner in Live Rats. J Alzheimers Dis 2022; 89:335-350. [PMID: 35871344 PMCID: PMC9484260 DOI: 10.3233/jad-220351] [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] [Indexed: 11/15/2022]
Abstract
Background: Cognitive decline in Alzheimer’s disease (AD) correlates with the extent of tau pathology, in particular tau hyperphosphorylation, which is strongly age-associated. Although elevation of cerebrospinal fluid or blood levels of phosphorylated tau (p-Tau) at residues Thr181 (p-Tau181), Thr217 (p-Tau217), and Thr231 (p-Tau231) are proposed to be particularly sensitive markers of preclinical AD, the generation of p-Tau during brain activity is poorly understood. Objective: To study whether the expression levels of p-Tau181, p-Tau217, and p-Tau231 can be enhanced by physiological synaptic long-term depression (LTD) which has been linked to the enhancement of p-Tau in hippocampus. Methods: In vivo electrophysiology was performed in urethane anesthetized young adult and aged male rats. Low frequency electrical stimulation (LFS) was used to induce LTD at CA3 to CA1 synapses. The expression level of p-Tau and total tau was measured in dorsal hippocampus using immunofluorescent staining and/or western blotting. Results: We found that LFS enhanced p-Tau181 and p-Tau217 in an age-dependent manner in the hippocampus of live rats. In contrast, phosphorylation at residues Thr231, Ser202/Thr205, and Ser396 appeared less sensitive to LFS. Pharmacological antagonism of either N-methyl-D-aspartate or metabotropic glutamate 5 receptors inhibited the elevation of both p-Tau181 and p-Tau217. Targeting the integrated stress response, which increases with aging, using a small molecule inhibitor ISRIB, prevented the enhancement of p-Tau by LFS in aged rats. Conclusion: Together, our data provide a novel in vivo means to uncover brain plasticity-related cellular and molecular processes of tau phosphorylation at key sites in health and aging.
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Affiliation(s)
- Yangyang Zhang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yin Yang
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Zhengtao Hu
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
- Department of Gerontology, The First Affiliated Hospital of Wannan Medical College, Wuhu, China
| | - Manyi Zhu
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Shuangying Qin
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Pengpeng Yu
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
- Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Bo Li
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Jitian Xu
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Tomas Ondrejcak
- Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Igor Klyubin
- Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Michael J. Rowan
- Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Neng-Wei Hu
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
- Department of Pharmacology & Therapeutics and Institute of Neuroscience, Trinity College, Dublin, Ireland
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13
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Estimating the glutamate transporter surface density in distinct sub-cellular compartments of mouse hippocampal astrocytes. PLoS Comput Biol 2022; 18:e1009845. [PMID: 35120128 PMCID: PMC8849624 DOI: 10.1371/journal.pcbi.1009845] [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: 05/24/2021] [Revised: 02/16/2022] [Accepted: 01/18/2022] [Indexed: 11/19/2022] Open
Abstract
Glutamate transporters preserve the spatial specificity of synaptic transmission by limiting glutamate diffusion away from the synaptic cleft, and prevent excitotoxicity by keeping the extracellular concentration of glutamate at low nanomolar levels. Glutamate transporters are abundantly expressed in astrocytes, and previous estimates have been obtained about their surface expression in astrocytes of the rat hippocampus and cerebellum. Analogous estimates for the mouse hippocampus are currently not available. In this work, we derive the surface density of astrocytic glutamate transporters in mice of different ages via quantitative dot blot. We find that the surface density of glial glutamate transporters is similar in 7-8 week old mice and rats. In mice, the levels of glutamate transporters increase until about 6 months of age and then begin to decline slowly. Our data, obtained from a combination of experimental and modeling approaches, point to the existence of stark differences in the density of expression of glutamate transporters across different sub-cellular compartments, indicating that the extent to which astrocytes limit extrasynaptic glutamate diffusion depends not only on their level of synaptic coverage, but also on the identity of the astrocyte compartment in contact with the synapse. Together, these findings provide information on how heterogeneity in the spatial distribution of glutamate transporters in the plasma membrane of hippocampal astrocytes my alter glutamate receptor activation out of the synaptic cleft.
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14
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Setti SE, Reed MN. Network activity changes in the pathophysiology of Alzheimer's disease: the role of aging and early entorhinal cortex dysfunction. Metab Brain Dis 2022; 37:289-298. [PMID: 34591222 DOI: 10.1007/s11011-021-00848-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 09/23/2021] [Indexed: 11/24/2022]
Abstract
The greatest risk factor for development of the deadly neurodegenerative disorder known as Alzheimer's disease (AD) is advancing age. Currently unknown is what mediates the impact of advanced age on development of AD. Also unknown is what impact activity alterations in the entorhinal cortex (EC) has on the spread of AD pathology such as pathological tau through the brain as AD progresses. This review focuses on evidence in the literature that describes how one potential age-related change, that of glutamate-mediated increases in neuronal activity, may ultimately increase the risk of developing AD and promote the spread of tau pathology in AD-affected brains from the EC to later regions such as the hippocampus and prefrontal cortex. A better understanding of these detrimental alterations may allow for earlier detection of AD, offering a better prognosis for affected individuals.
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Affiliation(s)
- Sharay E Setti
- Department of Drug Discovery and Development, Auburn University, 720 South Donahue, Auburn, AL, 36849, USA
- Center for Neuroscience Initiative, Auburn University, Auburn, AL, USA
| | - Miranda N Reed
- Department of Drug Discovery and Development, Auburn University, 720 South Donahue, Auburn, AL, 36849, USA.
- Center for Neuroscience Initiative, Auburn University, Auburn, AL, USA.
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15
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Bobermin LD, de Souza Almeida RR, Weber FB, Medeiros LS, Medeiros L, Wyse ATS, Gonçalves CA, Quincozes-Santos A. Lipopolysaccharide Induces Gliotoxicity in Hippocampal Astrocytes from Aged Rats: Insights About the Glioprotective Roles of Resveratrol. Mol Neurobiol 2022; 59:1419-1439. [PMID: 34993844 DOI: 10.1007/s12035-021-02664-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 11/23/2021] [Indexed: 12/13/2022]
Abstract
Astrocytes may undergo a functional remodeling with aging, acquiring a pro-inflammatory state. In line with this, resveratrol represents an interesting strategy for a healthier brain aging since it can improve glial functions. In the present study, we investigated the glioprotective role of resveratrol against lipopolysaccharide (LPS)-induced gliotoxicity in hippocampal aged astrocytes. Astrocyte cultures were obtained from aged rats (365 days old) and challenged in vitro with LPS in the presence of resveratrol. Cultured astrocytes from newborn rats were used as an age comparative for evaluating LPS gliotoxicity. In addition, aged rats were submitted to an acute systemic inflammation with LPS. Hippocampal astrocyte cultures were also obtained from these LPS-stimulated aged animals to further investigate the glioprotective effects of resveratrol in vitro. Overall, our results show that LPS induced a higher inflammatory response in aged astrocytes, compared to newborn astrocytes. Several inflammatory and gene expression alterations promoted by LPS in aged astrocyte cultures were similar in hippocampal tissue from aged animals submitted to in vivo LPS injection, corroborating our in vitro findings. Resveratrol, in turn, presented anti-inflammatory effects in aged astrocyte cultures, which were associated with downregulation of p21 and pro-inflammatory cytokines, Toll-like receptors (TLRs), and nuclear factor κB (NFκB). Resveratrol also improved astroglial functions. Upregulation of sirtuin 1 (SIRT1), nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase 1 (HO-1) represent potential molecular mechanisms associated with resveratrol-mediated glioprotection. In summary, our data show that resveratrol can prime aged astrocytes against gliotoxic stimuli, contributing to a healthier brain aging.
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Affiliation(s)
- Larissa Daniele Bobermin
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Rômulo Rodrigo de Souza Almeida
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Fernanda Becker Weber
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul- UFRGS, Rua Ramiro Barcelos, 2600 - Anexo Bairro Santa Cecília, Porto Alegre, RS, Brazil
| | - Lara Scopel Medeiros
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul- UFRGS, Rua Ramiro Barcelos, 2600 - Anexo Bairro Santa Cecília, Porto Alegre, RS, Brazil
| | - Lívia Medeiros
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul- UFRGS, Rua Ramiro Barcelos, 2600 - Anexo Bairro Santa Cecília, Porto Alegre, RS, Brazil
| | - Angela T S Wyse
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil.,Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul- UFRGS, Rua Ramiro Barcelos, 2600 - Anexo Bairro Santa Cecília, Porto Alegre, RS, Brazil
| | - Carlos-Alberto Gonçalves
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil.,Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul- UFRGS, Rua Ramiro Barcelos, 2600 - Anexo Bairro Santa Cecília, Porto Alegre, RS, Brazil
| | - André Quincozes-Santos
- Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil. .,Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul- UFRGS, Rua Ramiro Barcelos, 2600 - Anexo Bairro Santa Cecília, Porto Alegre, RS, Brazil.
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16
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Verbruggen L, Ates G, Lara O, De Munck J, Villers A, De Pauw L, Ottestad-Hansen S, Kobayashi S, Beckers P, Janssen P, Sato H, Zhou Y, Hermans E, Njemini R, Arckens L, Danbolt NC, De Bundel D, Aerts JL, Barbé K, Guillaume B, Ris L, Bentea E, Massie A. Lifespan extension with preservation of hippocampal function in aged system x c--deficient male mice. Mol Psychiatry 2022; 27:2355-2368. [PMID: 35181756 PMCID: PMC9126817 DOI: 10.1038/s41380-022-01470-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 01/11/2022] [Accepted: 02/02/2022] [Indexed: 11/25/2022]
Abstract
The cystine/glutamate antiporter system xc- has been identified as the major source of extracellular glutamate in several brain regions as well as a modulator of neuroinflammation, and genetic deletion of its specific subunit xCT (xCT-/-) is protective in mouse models for age-related neurological disorders. However, the previously observed oxidative shift in the plasma cystine/cysteine ratio of adult xCT-/- mice led to the hypothesis that system xc- deletion would negatively affect life- and healthspan. Still, till now the role of system xc- in physiological aging remains unexplored. We therefore studied the effect of xCT deletion on the aging process of mice, with a particular focus on the immune system, hippocampal function, and cognitive aging. We observed that male xCT-/- mice have an extended lifespan, despite an even more increased plasma cystine/cysteine ratio in aged compared to adult mice. This oxidative shift does not negatively impact the general health status of the mice. On the contrary, the age-related priming of the innate immune system, that manifested as increased LPS-induced cytokine levels and hypothermia in xCT+/+ mice, was attenuated in xCT-/- mice. While this was associated with only a very moderate shift towards a more anti-inflammatory state of the aged hippocampus, we observed changes in the hippocampal metabolome that were associated with a preserved hippocampal function and the retention of hippocampus-dependent memory in male aged xCT-/- mice. Targeting system xc- is thus not only a promising strategy to prevent cognitive decline, but also to promote healthy aging.
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Affiliation(s)
- Lise Verbruggen
- grid.8767.e0000 0001 2290 8069Laboratory of Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Gamze Ates
- grid.8767.e0000 0001 2290 8069Laboratory of Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Olaya Lara
- grid.8767.e0000 0001 2290 8069Laboratory of Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Jolien De Munck
- grid.8767.e0000 0001 2290 8069Laboratory of Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Agnès Villers
- grid.8364.90000 0001 2184 581XDepartment of Neurosciences, Université de Mons (UMONS), Mons, Belgium
| | - Laura De Pauw
- grid.8767.e0000 0001 2290 8069Laboratory of Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Sigrid Ottestad-Hansen
- grid.5510.10000 0004 1936 8921Neurotransporter Group, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Sho Kobayashi
- grid.268394.20000 0001 0674 7277Department of Food, Life and Environmental Science, Faculty of Agriculture, Yamagata University, Yamagata, Japan
| | - Pauline Beckers
- grid.7942.80000 0001 2294 713XInstitute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Pauline Janssen
- grid.8767.e0000 0001 2290 8069Laboratory of Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Hideyo Sato
- grid.260975.f0000 0001 0671 5144Department of Medical Technology, Niigata University, Niigata, Japan
| | - Yun Zhou
- grid.5510.10000 0004 1936 8921Neurotransporter Group, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Emmanuel Hermans
- grid.7942.80000 0001 2294 713XInstitute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Rose Njemini
- grid.8767.e0000 0001 2290 8069Frailty in Ageing research Department, VUB, Brussels, Belgium
| | - Lutgarde Arckens
- grid.5596.f0000 0001 0668 7884Laboratory of Neuroplasticity and Neuroproteomics, and Leuven Brain Institute (LBI), University of Leuven, Leuven, Belgium
| | - Niels C. Danbolt
- grid.5510.10000 0004 1936 8921Neurotransporter Group, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Dimitri De Bundel
- grid.8767.e0000 0001 2290 8069Pharmaceutical Chemistry, Drug Analysis and Drug Information, C4N, VUB, Brussels, Belgium
| | - Joeri L. Aerts
- grid.8767.e0000 0001 2290 8069Laboratory of Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Kurt Barbé
- grid.8767.e0000 0001 2290 8069The Biostatistics and Medical Informatics Department, VUB, Brussels, Belgium
| | | | - Laurence Ris
- grid.8364.90000 0001 2184 581XDepartment of Neurosciences, Université de Mons (UMONS), Mons, Belgium
| | - Eduard Bentea
- grid.8767.e0000 0001 2290 8069Laboratory of Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Ann Massie
- Laboratory of Neuro-Aging & Viro-Immunotherapy, Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), Brussels, Belgium.
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17
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Differential Effects of Human P301L Tau Expression in Young versus Aged Mice. Int J Mol Sci 2021; 22:ijms222111637. [PMID: 34769068 PMCID: PMC8583766 DOI: 10.3390/ijms222111637] [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: 09/20/2021] [Revised: 10/20/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
The greatest risk factor for developing Alzheimer’s disease (AD) is increasing age. Understanding the changes that occur in aging that make an aged brain more susceptible to developing AD could result in novel therapeutic targets. In order to better understand these changes, the current study utilized mice harboring a regulatable mutant P301L human tau transgene (rTg(TauP301L)4510), in which P301L tau expression can be turned off or on by the addition or removal of doxycycline in the drinking water. This regulatable expression allowed for assessment of aging independent of prolonged mutant tau expression. Our results suggest that P301L expression in aged mice enhances memory deficits in the Morris water maze task. These behavioral changes may be due to enhanced late-stage tau pathology, as evidenced by immunoblotting and exacerbated hippocampal dysregulation of glutamate release and uptake measured by the microelectrode array technique. We additionally observed changes in proteins important for the regulation of glutamate and tau phosphorylation that may mediate these age-related changes. Thus, age and P301L tau interact to exacerbate tau-induced detrimental alterations in aged animals.
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18
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P2X7-deficiency improves plasticity and cognitive abilities in a mouse model of Tauopathy. Prog Neurobiol 2021; 206:102139. [PMID: 34391810 DOI: 10.1016/j.pneurobio.2021.102139] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 07/06/2021] [Accepted: 08/06/2021] [Indexed: 12/29/2022]
Abstract
Alzheimer's disease is the most common form of dementia characterized by intracellular aggregates of hyperphosphorylated Tau protein and extracellular accumulation of amyloid β (Aβ) peptides. We previously demonstrated that the purinergic receptor P2X7 (P2X7) plays a major role in Aβ-mediated neurodegeneration but the relationship between P2X7 and Tau remained overlooked. Such a link was supported by cortical upregulation of P2X7 in patients with various type of frontotemporal lobar degeneration, including mutation in the Tau-coding gene, MAPT, as well as in the brain of a Tauopathy mouse model (THY-Tau22). Subsequent phenotype analysis of P2X7-deficient Tau mice revealed the instrumental impact of this purinergic receptor. Indeed, while P2X7-deficiency had a moderate effect on Tau pathology itself, we observed a significant reduction of microglia activation and of Tau-related inflammatory mediators, particularly CCL4. Importantly, P2X7 deletion ultimately rescued synaptic plasticity and memory impairments of Tau mice. Altogether, the present data support a contributory role of P2X7 dysregulation on processes governing Tau-induced brain anomalies. Due to the convergent role of P2X7 blockade in both Aβ and Tau background, P2X7 inhibitors might prove to be ideal candidate drugs to curb the devastating cognitive decline in Alzheimer's disease and Tauopathies.
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19
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Andersen JV, Markussen KH, Jakobsen E, Schousboe A, Waagepetersen HS, Rosenberg PA, Aldana BI. Glutamate metabolism and recycling at the excitatory synapse in health and neurodegeneration. Neuropharmacology 2021; 196:108719. [PMID: 34273389 DOI: 10.1016/j.neuropharm.2021.108719] [Citation(s) in RCA: 120] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/01/2021] [Accepted: 07/13/2021] [Indexed: 02/08/2023]
Abstract
Glutamate is the primary excitatory neurotransmitter of the brain. Cellular homeostasis of glutamate is of paramount importance for normal brain function and relies on an intricate metabolic collaboration between neurons and astrocytes. Glutamate is extensively recycled between neurons and astrocytes in a process known as the glutamate-glutamine cycle. The recycling of glutamate is closely linked to brain energy metabolism and is essential to sustain glutamatergic neurotransmission. However, a considerable amount of glutamate is also metabolized and serves as a metabolic hub connecting glucose and amino acid metabolism in both neurons and astrocytes. Disruptions in glutamate clearance, leading to neuronal overstimulation and excitotoxicity, have been implicated in several neurodegenerative diseases. Furthermore, the link between brain energy homeostasis and glutamate metabolism is gaining attention in several neurological conditions. In this review, we provide an overview of the dynamics of synaptic glutamate homeostasis and the underlying metabolic processes with a cellular focus on neurons and astrocytes. In particular, we review the recently discovered role of neuronal glutamate uptake in synaptic glutamate homeostasis and discuss current advances in cellular glutamate metabolism in the context of Alzheimer's disease and Huntington's disease. Understanding the intricate regulation of glutamate-dependent metabolic processes at the synapse will not only increase our insight into the metabolic mechanisms of glutamate homeostasis, but may reveal new metabolic targets to ameliorate neurodegeneration.
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Affiliation(s)
- Jens V Andersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
| | - Kia H Markussen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Department of Molecular and Cellular Biochemistry, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Helle S Waagepetersen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Paul A Rosenberg
- Department of Neurology and the F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA; Program in Neuroscience, Harvard Medical School, Boston, MA, USA
| | - Blanca I Aldana
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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20
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Gasiorowska A, Wydrych M, Drapich P, Zadrozny M, Steczkowska M, Niewiadomski W, Niewiadomska G. The Biology and Pathobiology of Glutamatergic, Cholinergic, and Dopaminergic Signaling in the Aging Brain. Front Aging Neurosci 2021; 13:654931. [PMID: 34326765 PMCID: PMC8315271 DOI: 10.3389/fnagi.2021.654931] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 06/14/2021] [Indexed: 12/12/2022] Open
Abstract
The elderly population is growing worldwide, with important health and socioeconomic implications. Clinical and experimental studies on aging have uncovered numerous changes in the brain, such as decreased neurogenesis, increased synaptic defects, greater metabolic stress, and enhanced inflammation. These changes are associated with cognitive decline and neurobehavioral deficits. Although aging is not a disease, it is a significant risk factor for functional worsening, affective impairment, disease exaggeration, dementia, and general disease susceptibility. Conversely, life events related to mental stress and trauma can also lead to accelerated age-associated disorders and dementia. Here, we review human studies and studies on mice and rats, such as those modeling human neurodegenerative diseases, that have helped elucidate (1) the dynamics and mechanisms underlying the biological and pathological aging of the main projecting systems in the brain (glutamatergic, cholinergic, and dopaminergic) and (2) the effect of defective glutamatergic, cholinergic, and dopaminergic projection on disabilities associated with aging and neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases. Detailed knowledge of the mechanisms of age-related diseases can be an important element in the development of effective ways of treatment. In this context, we briefly analyze which adverse changes associated with neurodegenerative diseases in the cholinergic, glutaminergic and dopaminergic systems could be targeted by therapeutic strategies developed as a result of our better understanding of these damaging mechanisms.
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Affiliation(s)
- Anna Gasiorowska
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Malgorzata Wydrych
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Patrycja Drapich
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Maciej Zadrozny
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Marta Steczkowska
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Wiktor Niewiadomski
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Grazyna Niewiadomska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
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21
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Coelho-Júnior HJ, Calvani R, Landi F, Picca A, Marzetti E. Protein Intake and Cognitive Function in Older Adults: A Systematic Review and Meta-Analysis. Nutr Metab Insights 2021; 14:11786388211022373. [PMID: 34158801 PMCID: PMC8182191 DOI: 10.1177/11786388211022373] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/08/2021] [Indexed: 12/04/2022] Open
Abstract
Introduction: The present study investigated the association between protein intake and
cognitive function in older adults. Methods: We performed a literature search with no restriction on publication year in
MEDLINE, SCOPUS, CINAHL, AgeLine from inception up to October 2020.
Observational studies that investigated as a primary or secondary outcome
the association of protein intake and cognitive function in older adults
aged ⩾60 years were included. Results: Nine cross-sectional studies that investigated a total of 4929 older adults
were included in the qualitative analysis. Overall cognitive function was
examined in 6 studies. Four investigations reported null associations and 2
studies found that older adults with a high protein intake had higher global
cognitive function than their counterparts. Results from the meta-analysis
suggested that there were no significant associations between protein
consumption and global cognitive function in older adults, regardless of
gender. Three studies investigated other cognitive domains. Memory and
protein intake were significantly and positively correlated in all studies.
In addition, visuospatial, verbal fluency, processing speed, and sustained
attention were positively associated with protein consumption in 1 study
each. Conclusion: No significant associations between protein intake and global cognitive
function were observed in neither qualitative nor quantitative analyses. The
association between protein consumption with multiple other cognitive
domains were also tested. As a whole, 3 studies reported a positive and
significant association between high protein intake and memory, while 1
study observed a significant and positive association with visuospatial,
verbal fluency, processing speed, and sustained attention.
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Affiliation(s)
| | - Riccardo Calvani
- Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS, Rome, Italy
| | | | - Anna Picca
- Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS, Rome, Italy
| | - Emanuele Marzetti
- Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS, Rome, Italy
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22
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Ebersole J, Rose G, Eid T, Behar K, Patrylo P. Altered hippocampal astroglial metabolism is associated with aging and preserved spatial learning and memory. Neurobiol Aging 2021; 102:188-199. [PMID: 33774381 DOI: 10.1016/j.neurobiolaging.2021.02.015] [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: 02/21/2020] [Revised: 02/18/2021] [Accepted: 02/19/2021] [Indexed: 11/23/2022]
Abstract
An age-related decrease in hippocampal metabolism correlates with cognitive decline. Hippocampus-dependent learning and memory requires glutamatergic neurotransmission supported by glutamate-glutamine (GLU-GLN) cycling between neurons and astrocytes. We examined whether GLU-GLN cycling in hippocampal subregions (dentate gyrus and CA1) in Fischer 344 rats was altered with age and cognitive status. Hippocampal slices from young adult, aged cognitively-unimpaired (AU) and aged cognitively-impaired (AI) rats were incubated in artificial cerebrospinal fluid (aCSF) containing 1-13C-glucose to assess neural metabolism. Incorporation of 13C-glucose into glutamate and glutamine, measured by mass spectroscopy/liquid chromatography tandem mass spectroscopy, did not significantly differ between groups. However, when 13C-acetate, a preferential astrocytic metabolite, was used, a significant increase in 13C-labeled glutamate was observed in slices from AU rats. Taken together, the data suggest that resting state neural metabolism and GLU-GLN cycling may be preserved during aging when sufficient extracellular glucose is available, but that enhanced astroglial metabolism can occur under resting state conditions. This may be an aging-related compensatory change to maintain hippocampus-dependent cognitive function.
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Affiliation(s)
- Jeremy Ebersole
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, USA
| | - Gregory Rose
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, USA; Department of Anatomy, Southern Illinois University School of Medicine, Carbondale, IL, USA; Center for Integrated Research in the Cognitive and Neural Sciences, Southern Illinois University School of Medicine, Carbondale, IL, USA
| | - Tore Eid
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Kevin Behar
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; MRRC Neurometabolism Research Laboratory, Yale University School of Medicine, New Haven, CT, USA
| | - Peter Patrylo
- Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, USA; Department of Anatomy, Southern Illinois University School of Medicine, Carbondale, IL, USA; Center for Integrated Research in the Cognitive and Neural Sciences, Southern Illinois University School of Medicine, Carbondale, IL, USA.
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23
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Chu SF, Zhang Z, Zhou X, He WB, Yang B, Cui LY, He HY, Wang ZZ, Chen NH. Low corticosterone levels attenuate late life depression and enhance glutamatergic neurotransmission in female rats. Acta Pharmacol Sin 2021; 42:848-860. [PMID: 33028984 PMCID: PMC8149629 DOI: 10.1038/s41401-020-00536-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 09/11/2020] [Indexed: 12/24/2022] Open
Abstract
Sustained elevation of corticosterone (CORT) is one of the common causes of aging and major depression disorder. However, the role of elevated CORT in late life depression (LLD) has not been elucidated. In this study, 18-month-old female rats were subjected to bilateral adrenalectomy or sham surgery. Their CORT levels in plasma were adjusted by CORT replacement and the rats were divided into high-level CORT (H-CORT), low-level CORT (L-CORT), and Sham group. We showed that L-CORT rats displayed attenuated depressive symptoms and memory defects in behavioral tests as compared with Sham or H-CORT rats. Furthermore, we showed that glutamatergic transmission was enhanced in L-CORT rats, evidenced by enhanced population spike amplitude (PSA) recorded from the dentate gyrus of hippocampus in vivo and increased glutamate release from hippocampal synaptosomes caused by high frequency stimulation or CORT exposure. Intracerebroventricular injection of an enzymatic glutamate scavenger system, glutamic-pyruvic transmine (GPT, 1 μM), significantly increased the PSA in Sham rats, suggesting that extracelluar accumulation of glutamate might be the culprit of impaired glutamatergic transmission, which was dependent on the uptake by Glt-1 in astrocytes. We revealed that hippocampal Glt-1 expression level in the L-CORT rats was much higher than in Sham and H-CORT rats. In a gradient neuron-astrocyte coculture, we found that the expression of Glt-1 was decreased with the increase of neural percentage, suggesting that impairment of Glt-1 might result from the high level of CORT contributed neural damage. In sham rats, administration of DHK that inhibited Glt-1 activity induced significant LLD symptoms, whereas administration of RIL that promoted glutamate uptake significantly attenuated LLD. All of these results suggest that glutamatergic transmission impairment is one of important pathogenesis in LLD induced by high level of CORT, which provide promising clues for the treatment of LLD.
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Affiliation(s)
- Shi-Feng Chu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Zhao Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Xin Zhou
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Wen-Bin He
- Shanxi Key Laboratory of Chinese Medicine Encephalopathy, Shanxi University of Chinese Medicine, Jinzhong, 030619, China
| | - Bo Yang
- Department of Pharmacy, Characteristic Medical Center of the Chinese People's Armed Police Force, Tianjin, 300300, China
| | - Li-Yuan Cui
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Hong-Yuan He
- Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica and Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.
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24
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Todd AC, Hardingham GE. The Regulation of Astrocytic Glutamate Transporters in Health and Neurodegenerative Diseases. Int J Mol Sci 2020; 21:E9607. [PMID: 33348528 PMCID: PMC7766851 DOI: 10.3390/ijms21249607] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 12/04/2020] [Accepted: 12/11/2020] [Indexed: 12/24/2022] Open
Abstract
The astrocytic glutamate transporters excitatory amino acid transporters 1 and 2 (EAAT1 and EAAT2) play a key role in nervous system function to maintain extracellular glutamate levels at low levels. In physiology, this is essential for the rapid uptake of synaptically released glutamate, maintaining the temporal fidelity of synaptic transmission. However, EAAT1/2 hypo-expression or hypo-function are implicated in several disorders, including epilepsy and neurodegenerative diseases, as well as being observed naturally with aging. This not only disrupts synaptic information transmission, but in extremis leads to extracellular glutamate accumulation and excitotoxicity. A key facet of EAAT1/2 expression in astrocytes is a requirement for signals from other brain cell types in order to maintain their expression. Recent evidence has shown a prominent role for contact-dependent neuron-to-astrocyte and/or endothelial cell-to-astrocyte Notch signalling for inducing and maintaining the expression of these astrocytic glutamate transporters. The relevance of this non-cell-autonomous dependence to age- and neurodegenerative disease-associated decline in astrocytic EAAT expression is discussed, plus the implications for disease progression and putative therapeutic strategies.
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Affiliation(s)
- Alison C. Todd
- UK Dementia Research Institute at the University of Edinburgh, Chancellor’s Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK;
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Giles E. Hardingham
- UK Dementia Research Institute at the University of Edinburgh, Chancellor’s Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK;
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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25
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Verkhratsky A, Augusto-Oliveira M, Pivoriūnas A, Popov A, Brazhe A, Semyanov A. Astroglial asthenia and loss of function, rather than reactivity, contribute to the ageing of the brain. Pflugers Arch 2020; 473:753-774. [PMID: 32979108 DOI: 10.1007/s00424-020-02465-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/05/2020] [Accepted: 09/09/2020] [Indexed: 12/13/2022]
Abstract
Astroglia represent a class of heterogeneous, in form and function, cells known as astrocytes, which provide for homoeostasis and defence of the central nervous system (CNS). Ageing is associated with morphological and functional remodelling of astrocytes with a prevalence of morphological atrophy and loss of function. In particular, ageing is associated with (i) decrease in astroglial synaptic coverage, (ii) deficits in glutamate and potassium clearance, (iii) reduced astroglial synthesis of synaptogenic factors such as cholesterol, (iv) decrease in aquaporin 4 channels in astroglial endfeet with subsequent decline in the glymphatic clearance, (v) decrease in astroglial metabolic support through the lactate shuttle, (vi) dwindling adult neurogenesis resulting from diminished proliferative capacity of radial stem astrocytes, (vii) decline in the astroglial-vascular coupling and deficient blood-brain barrier and (viii) decrease in astroglial ability to mount reactive astrogliosis. Decrease in reactive capabilities of astroglia are associated with rise of age-dependent neurodegenerative diseases. Astroglial morphology and function can be influenced and improved by lifestyle interventions such as intellectual engagement, social interactions, physical exercise, caloric restriction and healthy diet. These modifications of lifestyle are paramount for cognitive longevity.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK. .,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain. .,Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain.
| | - Marcus Augusto-Oliveira
- Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, 66075-110, Brazil
| | - Augustas Pivoriūnas
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, LT-01102, Vilnius, Lithuania
| | - Alexander Popov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya street 16/10, Moscow, Russia, 117997
| | - Alexey Brazhe
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya street 16/10, Moscow, Russia, 117997.,Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya street 16/10, Moscow, Russia, 117997. .,Sechenov First Moscow State Medical University, Moscow, Russia.
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26
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Srivastava I, Vazquez-Juarez E, Lindskog M. Reducing Glutamate Uptake in Rat Hippocampal Slices Enhances Astrocytic Membrane Depolarization While Down-Regulating CA3-CA1 Synaptic Response. Front Synaptic Neurosci 2020; 12:37. [PMID: 32973483 PMCID: PMC7461906 DOI: 10.3389/fnsyn.2020.00037] [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: 03/26/2020] [Accepted: 07/30/2020] [Indexed: 12/31/2022] Open
Abstract
The majority of synaptic activity in the brain consists of glutamatergic transmission, and there are numerous mechanisms, both intra- and inter-cellular that regulate this excitatory synaptic activity. Importantly, uptake of glutamate plays an important role and a reduced level of astrocytic glutamate transporters affect the normally balanced neurotransmission and is observed in many mental disorders. However, reduced glutamate uptake affects many different synaptic mechanisms in the astrocyte as well as in the neuron, and the effects are challenging to delineate. Combining electrophysiological recordings from neurons and astrocytes as well as extracellular glutamate recordings in rat hippocampal slices, we confirmed previous work showing that synaptic stimulation induces a long-lasting depolarization of the astrocytic membrane that is dependent on inward-rectifier potassium channels. We further showed that when glutamate transporters are blocked, this astrocytic depolarization is greatly enhanced although synaptic responses are reduced. We propose that increasing the levels of synaptic glutamate through blocking glutamate transporters reduces the AMPA-mediated synaptic response while the NMDA receptor current increases, contributing to a rise in extracellular K+ leading to enhanced astrocytic depolarization.
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Affiliation(s)
- Ipsit Srivastava
- Division of Neurogeriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| | - Erika Vazquez-Juarez
- Division of Neurogeriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
| | - Maria Lindskog
- Division of Neurogeriatrics, Center for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Solna, Sweden
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27
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Sharma A, Kazim SF, Larson CS, Ramakrishnan A, Gray JD, McEwen BS, Rosenberg PA, Shen L, Pereira AC. Divergent roles of astrocytic versus neuronal EAAT2 deficiency on cognition and overlap with aging and Alzheimer's molecular signatures. Proc Natl Acad Sci U S A 2019; 116:21800-21811. [PMID: 31591195 PMCID: PMC6815169 DOI: 10.1073/pnas.1903566116] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The excitatory amino acid transporter 2 (EAAT2) is the major glutamate transporter in the brain expressed predominantly in astrocytes and at low levels in neurons and axonal terminals. EAAT2 expression is reduced in aging and sporadic Alzheimer's disease (AD) patients' brains. The role EAAT2 plays in cognitive aging and its associated mechanisms remains largely unknown. Here, we show that conditional deletion of astrocytic and neuronal EAAT2 results in age-related cognitive deficits. Astrocytic, but not neuronal EAAT2, deletion leads to early deficits in short-term memory and in spatial reference learning and long-term memory. Neuronal EAAT2 loss results in late-onset spatial reference long-term memory deficit. Neuronal EAAT2 deletion leads to dysregulation of the kynurenine pathway, and astrocytic EAAT2 deficiency results in dysfunction of innate and adaptive immune pathways, which correlate with cognitive decline. Astrocytic EAAT2 deficiency also shows transcriptomic overlaps with human aging and AD. Overall, the present study shows that in addition to the widely recognized astrocytic EAAT2, neuronal EAAT2 plays a role in hippocampus-dependent memory. Furthermore, the gene expression profiles associated with astrocytic and neuronal EAAT2 deletion are substantially different, with the former associated with inflammation and synaptic function similar to changes observed in human AD and gene expression changes associated with inflammation similar to the aging human brain.
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Affiliation(s)
- Abhijeet Sharma
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Syed Faraz Kazim
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Chloe S Larson
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065
| | - Aarthi Ramakrishnan
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Jason D Gray
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065
| | - Bruce S McEwen
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY 10065;
| | - Paul A Rosenberg
- Department of Neurology and the F. M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115
- Program in Neuroscience, Harvard Medical School, Boston, MA 02115
| | - Li Shen
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Ana C Pereira
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029;
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
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28
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Matsuno M, Horiuchi J, Ofusa K, Masuda T, Saitoe M. Inhibiting Glutamate Activity during Consolidation Suppresses Age-Related Long-Term Memory Impairment in Drosophila. iScience 2019; 15:55-65. [PMID: 31030182 PMCID: PMC6487374 DOI: 10.1016/j.isci.2019.04.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 12/24/2018] [Accepted: 04/08/2019] [Indexed: 01/17/2023] Open
Abstract
In Drosophila, long-term memory (LTM) formation requires increases in glial gene expression. Klingon (Klg), a cell adhesion molecule expressed in both neurons and glia, induces expression of the glial transcription factor, Repo. However, glial signaling downstream of Repo has been unclear. Here we demonstrate that Repo increases expression of the glutamate transporter, EAAT1, and EAAT1 is required during consolidation of LTM. The expressions of Klg, Repo, and EAAT1 decrease upon aging, suggesting that age-related impairments in LTM are caused by dysfunction of the Klg-Repo-EAAT1 pathway. Supporting this idea, overexpression of Repo or EAAT1 rescues age-associated impairments in LTM. Pharmacological inhibition of glutamate activity during consolidation improves LTM in klg mutants and aged flies. Altogether, our results indicate that LTM formation requires glial-dependent inhibition of glutamate signaling during memory consolidation, and aging disrupts this process by inhibiting the Klg-Repo-EAAT1 pathway.
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Affiliation(s)
- Motomi Matsuno
- Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-8502, Japan
| | - Junjiro Horiuchi
- Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-8502, Japan
| | - Kyoko Ofusa
- Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-8502, Japan
| | - Tomoko Masuda
- Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-8502, Japan
| | - Minoru Saitoe
- Tokyo Metropolitan Institute of Medical Science, Setagaya, Tokyo 156-8502, Japan.
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29
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Lesuis SL, Kaplick PM, Lucassen PJ, Krugers HJ. Treatment with the glutamate modulator riluzole prevents early life stress-induced cognitive deficits and impairments in synaptic plasticity in APPswe/PS1dE9 mice. Neuropharmacology 2019; 150:175-183. [PMID: 30794835 DOI: 10.1016/j.neuropharm.2019.02.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 02/14/2019] [Accepted: 02/16/2019] [Indexed: 12/26/2022]
Abstract
BACKGROUND Environmental factors like stress affect age-related cognitive deficits and promote Alzheimer's disease (AD)-related pathology in mice. Excess glutamate has been proposed as a possible mediator underlying these effects in the hippocampus, a vulnerable brain region implicated in learning and memory. METHODS Here, we examined a) whether stress applied during a sensitive developmental period early in life affects later synaptic plasticity, learning and memory and plaque load in the APPswe/PS1dE9 mouse model for Alzheimer's disease and b) whether these effects could be rescued using long-term treatment with the glutamate modulator riluzole. RESULTS Our results demonstrate that ELS impairs synaptic plasticity in 6-month-old mice and increases plaque load in 12-month-old APPswe/PS1dE9 mice, while impairing flexible spatial learning in the Barnes maze at this age. Notably, spatial learning correlated well with hippocampal expression of the transporter EAAT2, which is important for extracellular glutamate uptake. The changes in LTP, plaque load and cognition after ELS were all prevented by riluzole treatment that started from post-weaning. CONCLUSION These results suggest that normalising glutamate signalling may be a viable therapeutic strategy for treating vulnerable individuals at risk of developing stress-aggravated AD, particularly in relation to adverse early life experiences.
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Affiliation(s)
- Sylvie L Lesuis
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands.
| | - Paul M Kaplick
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands.
| | - Paul J Lucassen
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands.
| | - Harm J Krugers
- Brain Plasticity Group, SILS-CNS, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, the Netherlands.
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30
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Oleson S, Eagan D, Kaur S, Hertzing WJ, Alkatan M, Davis JN, Tanaka H, Haley AP. Apolipoprotein E genotype moderates the association between dietary polyunsaturated fat and brain function: an exploration of cerebral glutamate and cognitive performance. Nutr Neurosci 2018; 23:696-705. [PMID: 30465491 DOI: 10.1080/1028415x.2018.1547857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Objective: To investigate the effect of Apolipoprotein E (APOE) genotype on the association between dietary polyunsaturated fat (PUFA), cognitive function, and cerebral glutamate. Methods: A participant sample of 122 middle-aged adults were grouped according to APOE genotype (ϵ4 carrier or ϵ4 non-carrier) and asked to record dietary intake for three consecutive days. All participants also underwent neuropsychological testing and a proton magnetic resonance spectroscopy (1H MRS) scan to assess glutamate in the posterior cingulate cortex. Results: Multiple regression analyses revealed a significant interaction between APOE genotype and PUFA intake on memory performance, F(1,113) = 6.749, p = .016. Greater PUFA intake was associated with better memory performance in healthy middle-aged adults who were APOE ϵ4 non-carriers, but not for ϵ4 carriers. Furthermore, there was a significant interaction between APOE genotype and PUFA intake on cerebral glutamate, in that dietary PUFA was associated with greater cerebral glutamate in APOE ϵ4 carriers, but not for ϵ4 non-carriers, F(1,114) = 5.173, p = .025. Conclusions: The findings suggest that PUFA action on the brain differs according to APOE polymorphism and points towards cerebral glutamate as a potential marker of genetic risk for Alzheimer's disease (AD). Early treatment consisting of PUFA supplementation that is tailored to APOE genotype may be an important intervention for the prevention of cognitive decline.
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Affiliation(s)
- Stephanie Oleson
- Department of Psychology, The University of Texas at Austin, USA
| | - Danielle Eagan
- Department of Psychology, The University of Texas at Austin, USA
| | - Sonya Kaur
- Department of Psychology, The University of Texas at Austin, USA
| | | | - Mohammed Alkatan
- Department of Physical Education, The Public Authority for Applied Education and Training, Kuwait City, Kuwait.,Department of Kinesiology and Health Education, The University of Texas at Austin, USA
| | - Jaimie N Davis
- Department of Nutritional Sciences, The University of Texas at Austin, USA
| | - Hirofumi Tanaka
- Department of Kinesiology and Health Education, The University of Texas at Austin, USA
| | - Andreana P Haley
- Department of Psychology, The University of Texas at Austin, USA
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Susceptibility to Aβo and TBOA of LTD and Extrasynaptic NMDAR-Dependent Tonic Current in the Aged Rat Hippocampus. Neurochem Res 2018; 44:692-702. [PMID: 30426348 DOI: 10.1007/s11064-018-2677-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 10/26/2018] [Accepted: 11/02/2018] [Indexed: 12/29/2022]
Abstract
Aging, as the major risk factor of Alzheimer's disease (AD), may increase susceptibility to neurodegenerative diseases through many gradual molecular and biochemical changes. Extracellular glutamate homeostasis and extrasynaptic glutamate N-methyl-D-aspartate receptors (NMDAR) are among early synaptic targets of oligomeric amyloid β (Aβo), one of the AD related synaptotoxic protein species. In this study, we asked for the effects of Aβo on long-term depression (LTD), a form of synaptic plasticity dependent on extrasynaptic NMDAR activation, and on a tonic current (TC) resulting from the activation of extrasynaptic NMDAR by ambient glutamate in hippocampal slices from young (3-6-month-old) and aged (24-28-month-old) Sprague-Dawley rats. Aβo significantly enhanced the magnitude of LTD and the amplitude of TC in aged slices compared to young ones. TBOA, a glutamate transporter inhibitor, also significantly increased LTD magnitude and TC amplitude in slices from aged rats, suggesting either an age-related weakness of the glutamate clearance system and/or a facilitated extrasynaptic NMDAR activation. From our present data, we hypothesize that senescence-related impairment of the extrasynaptic environment may be a vector of vulnerability of the aged hippocampus to neurodegenerative promotors such as Aβo.
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32
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Pál B. Involvement of extrasynaptic glutamate in physiological and pathophysiological changes of neuronal excitability. Cell Mol Life Sci 2018; 75:2917-2949. [PMID: 29766217 PMCID: PMC11105518 DOI: 10.1007/s00018-018-2837-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/27/2018] [Accepted: 05/07/2018] [Indexed: 12/14/2022]
Abstract
Glutamate is the most abundant neurotransmitter of the central nervous system, as the majority of neurons use glutamate as neurotransmitter. It is also well known that this neurotransmitter is not restricted to synaptic clefts, but found in the extrasynaptic regions as ambient glutamate. Extrasynaptic glutamate originates from spillover of synaptic release, as well as from astrocytes and microglia. Its concentration is magnitudes lower than in the synaptic cleft, but receptors responding to it have higher affinity for it. Extrasynaptic glutamate receptors can be found in neuronal somatodendritic location, on astroglia, oligodendrocytes or microglia. Activation of them leads to changes of neuronal excitability with different amplitude and kinetics. Extrasynaptic glutamate is taken up by neurons and astrocytes mostly via EAAT transporters, and astrocytes, in turn metabolize it to glutamine. Extrasynaptic glutamate is involved in several physiological phenomena of the central nervous system. It regulates neuronal excitability and synaptic strength by involving astroglia; contributing to learning and memory formation, neurosecretory and neuromodulatory mechanisms, as well as sleep homeostasis.The extrasynaptic glutamatergic system is affected in several brain pathologies related to excitotoxicity, neurodegeneration or neuroinflammation. Being present in dementias, neurodegenerative and neuropsychiatric diseases or tumor invasion in a seemingly uniform way, the system possibly provides a common component of their pathogenesis. Although parts of the system are extensively discussed by several recent reviews, in this review I attempt to summarize physiological actions of the extrasynaptic glutamate on neuronal excitability and provide a brief insight to its pathology for basic understanding of the topic.
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Affiliation(s)
- Balázs Pál
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, Debrecen, 4012, Hungary.
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33
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Evidence for altered dendritic spine compartmentalization in Alzheimer's disease and functional effects in a mouse model. Acta Neuropathol 2018; 135:839-854. [PMID: 29696365 DOI: 10.1007/s00401-018-1847-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/30/2018] [Accepted: 04/05/2018] [Indexed: 12/23/2022]
Abstract
Alzheimer's disease (AD) is associated with a progressive loss of synapses and neurons. Studies in animal models indicate that morphological alterations of dendritic spines precede synapse loss, increasing the proportion of large and short ("stubby") spines. Whether similar alterations occur in human patients, and what their functional consequences could be, is not known. We analyzed biopsies from AD patients and APP x presenilin 1 knock-in mice that were previously shown to present a loss of pyramidal neurons in the CA1 area of the hippocampus. We observed that the proportion of stubby spines and the width of spine necks are inversely correlated with synapse density in frontal cortical biopsies from non-AD and AD patients. In mice, the reduction in the density of synapses in the stratum radiatum was preceded by an alteration of spine morphology, with a reduction of their length and an enlargement of their neck. Serial sectioning examined with electron microscopy allowed us to precisely measure spine parameters. Mathematical modeling indicated that the shortening and widening of the necks should alter the electrical compartmentalization of the spines, leading to reduced postsynaptic potentials in spine heads, but not in soma. Accordingly, there was no alteration in basal synaptic transmission, but long-term potentiation and spatial memory were impaired. These results indicate that an alteration of spine morphology could be involved in the early cognitive deficits associated with AD.
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34
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Avila J, Llorens-Martín M, Pallas-Bazarra N, Bolós M, Perea JR, Rodríguez-Matellán A, Hernández F. Cognitive Decline in Neuronal Aging and Alzheimer's Disease: Role of NMDA Receptors and Associated Proteins. Front Neurosci 2017; 11:626. [PMID: 29176942 PMCID: PMC5687061 DOI: 10.3389/fnins.2017.00626] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 10/26/2017] [Indexed: 01/01/2023] Open
Abstract
Molecular changes associated with neuronal aging lead to a decrease in cognitive capacity. Here we discuss these alterations at the level of brain regions, brain cells, and brain membrane and cytoskeletal proteins with an special focus in NMDA molecular changes through aging and its effect in cognitive decline and Alzheimer disease. Here, we propose that some neurodegenerative disorders, like Alzheimer's disease (AD), are characterized by an increase and acceleration of some of these changes.
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Affiliation(s)
- Jesús Avila
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - María Llorens-Martín
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Noemí Pallas-Bazarra
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Marta Bolós
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Juan R Perea
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Alberto Rodríguez-Matellán
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Félix Hernández
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autonoma de Madrid (CSIC-UAM), Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud Carlos III (ISCIII), Madrid, Spain
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35
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Age and Alzheimer's disease gene expression profiles reversed by the glutamate modulator riluzole. Mol Psychiatry 2017; 22:296-305. [PMID: 27021815 PMCID: PMC5042881 DOI: 10.1038/mp.2016.33] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 01/27/2016] [Accepted: 02/12/2016] [Indexed: 01/21/2023]
Abstract
Alzheimer's disease (AD) and age-related cognitive decline represent a growing health burden and involve the hippocampus, a vulnerable brain region implicated in learning and memory. To understand the molecular effects of aging on the hippocampus, this study characterized the gene expression changes associated with aging in rodents using RNA-sequencing (RNA-seq). The glutamate modulator, riluzole, which was recently shown to improve memory performance in aged rats, prevented many of the hippocampal age-related gene expression changes. A comparison of the effects of riluzole in rats against human AD data sets revealed that many of the gene changes in AD are reversed by riluzole. Expression changes identified by RNA-Seq were validated by qRT-PCR open arrays. Riluzole is known to increase the glutamate transporter EAAT2's ability to scavenge excess glutamate, regulating synaptic transmission. RNA-seq and immunohistochemistry confirmed an increase in EAAT2 expression in hippocampus, identifying a possible mechanism underlying the improved memory function after riluzole treatment.
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36
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Cutuli D. Functional and Structural Benefits Induced by Omega-3 Polyunsaturated Fatty Acids During Aging. Curr Neuropharmacol 2017; 15:534-542. [PMID: 27306037 PMCID: PMC5543674 DOI: 10.2174/1570159x14666160614091311] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/16/2016] [Accepted: 05/31/2016] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Omega-3 polyunsaturated fatty acids (n-3 PUFA) are structural components of the brain and are indispensable for neuronal membrane synthesis. Along with decline in cognition, decreased synaptic density and neuronal loss, normal aging is accompanied by a reduction in n-3 PUFA concentration in the brain in both humans and rodents. Recently, many clinical and experimental studies have demonstrated the importance of n-3 PUFA in counteracting neurodegeneration and agerelated dysfunctions. METHODS This review will focus on the neuroprotective effects of n-3 PUFA on cognitive impairment, neuroinflammation and neurodegeneration during normal aging. Multiple pathways of n-3 PUFA preventive action will be examined. RESULTS Namely, n-3 PUFA have been shown to increase the levels of several signaling factors involved in synaptic plasticity, thus leading to the increase of dendritic spines and synapses as well as the enhancement of hippocampal neurogenesis even at old age. In elderly subjects n-3 PUFA exert anti-inflammatory effects associated with improved cognitive functions. Interestingly, growing evidence highlights n-3 PUFA efficacy in preventing the loss of both gray and white matter volume and integrity. CONCLUSION This review shows that n-3 PUFA are essential for a successful aging and appear as ideal cognitive enhancers to be implemented in nutritional interventions for the promotion of healthy aging.
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Affiliation(s)
- Debora Cutuli
- Fondazione Santa Lucia of Rome, Via del Fosso di Fiorano 64, 00143 Rome, Italy
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37
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Pinho J, Vale R, Batalha VL, Costenla AR, Dias R, Rombo D, Sebastião AM, de Mendonça A, Diógenes MJ. Enhanced LTP in aged rats: Detrimental or compensatory? Neuropharmacology 2016; 114:12-19. [PMID: 27889488 DOI: 10.1016/j.neuropharm.2016.11.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 09/22/2016] [Accepted: 11/22/2016] [Indexed: 11/19/2022]
Abstract
Age-dependent memory deterioration has been well documented and yet an increase in rat hippocampal LTP upon aging has been reported. This poses the question of whether the enhanced LTP is a cause or an attempt to compensate the memory deficits described in aged rats. Hippocampal slices from young, adult and aged Wistar rats were pre-incubated, with an NMDA receptor (NMDAR) antagonist, memantine (1 μM, 4 h), and hippocampal LTP was evaluated. The results show that memantine significantly decreases the larger LTP magnitude recorded in hippocampal slices from aged rats without compromising LTP recorded in slices from young and adult animals. To unveil the impact of in vivo administration of memantine, different doses (1, 5 and 10 mg/kg/day) or saline vehicle solution were intraperitoneally administered, for 15-20 days, to both young and aged animals. Memantine did not significantly affect neither the place learning of young animals, evaluated by Morris Water Maze, nor LTP recorded from hippocampal slices from the same group of animals. However, memantine (5 and 10 mg/kg/day) significantly decreased the large LTP recorded in hippocampal slices from aged animals. Moreover, aged animals treated with memantine (10 mg/kg/day) showed a significantly compromised place learning when compared to aged control animals. Overall, these results suggest that the larger LTP observed in aged animals is a compensatory phenomenon, rather than pathological. The finding that age-dependent blockade of LTP by a NMDAR antagonist leads to learning deficits, implies that the increased LTP observed upon aging may be playing an important role in the learning process.
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Affiliation(s)
- Júlia Pinho
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal.
| | - Ruben Vale
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal.
| | - Vânia L Batalha
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal.
| | - Ana Rita Costenla
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal.
| | - Raquel Dias
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal.
| | - Diogo Rombo
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal.
| | - Ana M Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal.
| | - Alexandre de Mendonça
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal.
| | - Maria José Diógenes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal; Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Portugal.
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Oleson S, Gonzales MM, Tarumi T, Davis JN, Cassill CK, Tanaka H, Haley AP. Nutrient intake and cerebral metabolism in healthy middle-aged adults: Implications for cognitive aging. Nutr Neurosci 2016; 20:489-496. [PMID: 27237189 DOI: 10.1080/1028415x.2016.1186341] [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] [Indexed: 12/31/2022]
Abstract
OBJECTIVES Growing evidence suggests dietary factors influence cognition, but the effects of nutrient intake on cerebral metabolism in adults are currently unknown. The present study investigated the relationship between major macronutrient intake (fat, carbohydrate, and protein) and cerebral neurochemical profiles in middle-aged adults. METHODS Thirty-six adults recorded dietary intake for 3 days prior to completing cognitive testing and a proton magnetic resonance spectroscopy (1H-MRS) scan. 1H-MRS of occipitoparietal gray matter was used to assess glutamate (Glu), N-acetyl-aspartate (NAA), choline (Cho), and myo-inositol (mI) relative to creatine (Cr) levels. RESULTS Regression analyses revealed that high intake of polyunsaturated fatty acids (PUFAs) was associated with lower cerebral Glu/Cr (P = 0.005), and high intake of saturated fat (SFA) was associated with poorer memory function (P = 0.030) independent of age, sex, education, estimated intelligence, total caloric intake, and body mass index. DISCUSSION In midlife, greater PUFA intake (ω-3 and ω-6) may be associated with lower cerebral glutamate, potentially indicating more efficient cellular reuptake of glutamate. SFA intake, on the other hand, was linked with poorer memory performance. These results suggest that dietary fat intake modification may be an important intervention target for the prevention of cognitive decline.
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Affiliation(s)
- Stephanie Oleson
- a Department of Psychology , The University of Texas at Austin , USA
| | - Mitzi M Gonzales
- a Department of Psychology , The University of Texas at Austin , USA
| | - Takashi Tarumi
- b Department of Kinesiology and Health Education , The University of Texas at Austin , USA
| | - Jaimie N Davis
- c Department of Nutritional Sciences , The University of Texas at Austin , USA
| | - Carolyn K Cassill
- a Department of Psychology , The University of Texas at Austin , USA
| | - Hirofumi Tanaka
- b Department of Kinesiology and Health Education , The University of Texas at Austin , USA
| | - Andreana P Haley
- a Department of Psychology , The University of Texas at Austin , USA
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39
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Perkins E, Suminaite D, Jackson M. Cerebellar ataxias: β-III spectrin's interactions suggest common pathogenic pathways. J Physiol 2016; 594:4661-76. [PMID: 26821241 PMCID: PMC4983618 DOI: 10.1113/jp271195] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 12/14/2015] [Indexed: 12/12/2022] Open
Abstract
Spinocerebellar ataxias (SCAs) are a genetically heterogeneous group of disorders all characterised by postural abnormalities, motor deficits and cerebellar degeneration. Animal and in vitro models have revealed β‐III spectrin, a cytoskeletal protein present throughout the soma and dendritic tree of cerebellar Purkinje cells, to be required for the maintenance of dendritic architecture and for the trafficking and/or stabilisation of several membrane proteins: ankyrin‐R, cell adhesion molecules, metabotropic glutamate receptor‐1 (mGluR1), voltage‐gated sodium channels (Nav) and glutamate transporters. This scaffold of interactions connects β‐III spectrin to a wide variety of proteins implicated in the pathology of many SCAs. Heterozygous mutations in the gene encoding β‐III spectrin (SPTBN2) underlie SCA type‐5 whereas homozygous mutations cause spectrin associated autosomal recessive ataxia type‐1 (SPARCA1), an infantile form of ataxia with cognitive impairment. Loss‐of β‐III spectrin function appears to underpin cerebellar dysfunction and degeneration in both diseases resulting in thinner dendrites, excessive dendritic protrusion with loss of planarity, reduced resurgent sodium currents and abnormal glutamatergic neurotransmission. The initial physiological consequences are a decrease in spontaneous activity and excessive excitation, likely to be offsetting each other, but eventually hyperexcitability gives rise to dark cell degeneration and reduced cerebellar output. Similar molecular mechanisms have been implicated for SCA1, 2, 3, 7, 13, 14, 19, 22, 27 and 28, highlighting alterations to intrinsic Purkinje cell activity, dendritic architecture and glutamatergic transmission as possible common mechanisms downstream of various loss‐of‐function primary genetic defects. A key question for future research is whether similar mechanisms underlie progressive cerebellar decline in normal ageing.
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Affiliation(s)
- Emma Perkins
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Daumante Suminaite
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Mandy Jackson
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
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40
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Early exposure to dynamic environments alters patterns of motor exploration throughout the lifespan. Behav Brain Res 2016; 302:81-7. [PMID: 26778790 DOI: 10.1016/j.bbr.2016.01.007] [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: 07/20/2015] [Revised: 12/01/2015] [Accepted: 01/05/2016] [Indexed: 11/21/2022]
Abstract
We assessed early rearing conditions on aging-related changes in mouse behavior. Two isolated-housing groups, running wheel (IHRW) and empty cage (IHEC), were compared against two enriched environments, static (EEST) and dynamic (EEDY), both of which included toys and other mice. For EEDY, the location of toys and sources of food and water changed daily, but remained constant for EEST. All mice, randomly assigned to one of the four groups at ∼4 weeks of age, remained in their respective environments for 25 weeks followed by single housing in empty cages. Beginning at ∼40 weeks of age, all mice were tested at monthly intervals in a plus-shaped maze in which we measured the number of arm entries and the probability of entering a perpendicular arm. Despite making significantly more arm entries than any other group, IHEC mice also were less likely to turn into the left or right arm, a sign of motor inflexibility. Both EEDY and EEST mice showed enhanced turning relative to IHRW and IHEC groups, but only EEDY mice maintained their turning performance for up to ∼100 weeks of age. EEDY and EEST mice also were unique in showing an increase in expression of the major glutamate transporter (GLT1) in striatum, but a decrease in motor cortex, suggesting a need for further assessment of environmental manipulations on long-term changes in forebrain glutamate transmission. Our behavioral results indicate that early exposure to continually changing environments, rather than socialization or exercise alone, results in life-long changes in patterns of motor exploration.
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Burlot MA, Braudeau J, Michaelsen-Preusse K, Potier B, Ayciriex S, Varin J, Gautier B, Djelti F, Audrain M, Dauphinot L, Fernandez-Gomez FJ, Caillierez R, Laprévote O, Bièche I, Auzeil N, Potier MC, Dutar P, Korte M, Buée L, Blum D, Cartier N. Cholesterol 24-hydroxylase defect is implicated in memory impairments associated with Alzheimer-like Tau pathology. Hum Mol Genet 2015; 24:5965-76. [PMID: 26358780 DOI: 10.1093/hmg/ddv268] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/06/2015] [Indexed: 01/01/2023] Open
Abstract
Alzheimer's disease (AD) is characterized by both amyloid and Tau pathologies. The amyloid component and altered cholesterol metabolism are closely linked, but the relationship between Tau pathology and cholesterol is currently unclear. Brain cholesterol is synthesized in situ and cannot cross the blood-brain barrier: to be exported from the central nervous system into the blood circuit, excess cholesterol must be converted to 24S-hydroxycholesterol by the cholesterol 24-hydroxylase encoded by the CYP46A1 gene. In AD patients, the concentration of 24S-hydroxycholesterol in the plasma and the cerebrospinal fluid are lower than in healthy controls. The THY-Tau22 mouse is a model of AD-like Tau pathology without amyloid pathology. We used this model to investigate the potential association between Tau pathology and CYP46A1 modulation. The amounts of CYP46A1 and 24S-hydroxycholesterol in the hippocampus were lower in THY-Tau22 than control mice. We used an adeno-associated virus (AAV) gene transfer strategy to increase CYP46A1 expression in order to investigate the consequences on THY-Tau22 mouse phenotype. Injection of the AAV-CYP46A1 vector into the hippocampus of THY-Tau22 mice led to CYP46A1 and 24S-hydroxycholesterol content normalization. The cognitive deficits, impaired long-term depression and spine defects that characterize the THY-Tau22 model were completely rescued, whereas Tau hyperphosphorylation and associated gliosis were unaffected. These results argue for a causal link between CYP46A1 protein content and memory impairments that result from Tau pathology. Therefore, CYP46A1 may be a relevant therapeutic target for Tauopathies and especially for AD.
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Affiliation(s)
- Marie-Anne Burlot
- INSERM U1169/MIRCen CEA, Fontenay aux Roses 92265, France, Université Paris-Sud, Université Paris-Saclay, Orsay 91400, France, Université Paris Descartes, Paris 75006, France
| | - Jérôme Braudeau
- INSERM U1169/MIRCen CEA, Fontenay aux Roses 92265, France, Université Paris-Sud, Université Paris-Saclay, Orsay 91400, France
| | - Kristin Michaelsen-Preusse
- Division of Cellular Neurobiology, Zoological Institute, University of Braunschweig, Braunschweig 38106, Germany, AG NIND, HZI, Inhoffenstraße 7, Braunschweig D-38124, Germany
| | - Brigitte Potier
- Centre de Psychiatrie et Neurosciences, Université Paris Descartes, Sorbonne Paris Cité, INSERM UMRS894, Paris 75014, France
| | | | - Jennifer Varin
- EA7331, Université Paris Descartes, Sorbonne Paris Cité, Faculté des Sciences Pharmaceutiques et Biologiques, Paris 75006, France
| | - Benoit Gautier
- INSERM U1169/MIRCen CEA, Fontenay aux Roses 92265, France, Université Paris-Sud, Université Paris-Saclay, Orsay 91400, France
| | - Fathia Djelti
- INSERM U1169/MIRCen CEA, Fontenay aux Roses 92265, France, Université Paris-Sud, Université Paris-Saclay, Orsay 91400, France, Université Paris Descartes, Paris 75006, France
| | - Mickael Audrain
- INSERM U1169/MIRCen CEA, Fontenay aux Roses 92265, France, Université Paris-Sud, Université Paris-Saclay, Orsay 91400, France, Université Paris Descartes, Paris 75006, France
| | - Luce Dauphinot
- ICM, Hopital Pitie-Salpetriere, CNRS UMR7225, INSERM UMRS975, UPMC, Paris 75013, France
| | - Francisco-Jose Fernandez-Gomez
- Université de Lille, UDSL, Lille 59045, France, INSERM UMR1172, Jean-Pierre Aubert Research Centre, Lille 59045, France and
| | - Raphaëlle Caillierez
- Université de Lille, UDSL, Lille 59045, France, INSERM UMR1172, Jean-Pierre Aubert Research Centre, Lille 59045, France and
| | | | - Ivan Bièche
- EA7331, Université Paris Descartes, Sorbonne Paris Cité, Faculté des Sciences Pharmaceutiques et Biologiques, Paris 75006, France
| | - Nicolas Auzeil
- Chimie-Toxicologie Analytique et Cellulaire, EA 4463 and
| | - Marie-Claude Potier
- ICM, Hopital Pitie-Salpetriere, CNRS UMR7225, INSERM UMRS975, UPMC, Paris 75013, France
| | - Patrick Dutar
- Centre de Psychiatrie et Neurosciences, Université Paris Descartes, Sorbonne Paris Cité, INSERM UMRS894, Paris 75014, France
| | - Martin Korte
- Division of Cellular Neurobiology, Zoological Institute, University of Braunschweig, Braunschweig 38106, Germany, AG NIND, HZI, Inhoffenstraße 7, Braunschweig D-38124, Germany
| | - Luc Buée
- Université de Lille, UDSL, Lille 59045, France, INSERM UMR1172, Jean-Pierre Aubert Research Centre, Lille 59045, France and CHRU-Lille, Faculté de Médecine, Lille 59037, France
| | - David Blum
- Université de Lille, UDSL, Lille 59045, France, INSERM UMR1172, Jean-Pierre Aubert Research Centre, Lille 59045, France and CHRU-Lille, Faculté de Médecine, Lille 59037, France
| | - Nathalie Cartier
- INSERM U1169/MIRCen CEA, Fontenay aux Roses 92265, France, Université Paris-Sud, Université Paris-Saclay, Orsay 91400, France,
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GLT-1 Transport Stoichiometry Is Constant at Low and High Glutamate Concentrations when Chloride Is Substituted by Gluconate. PLoS One 2015; 10:e0136111. [PMID: 26301411 PMCID: PMC4547712 DOI: 10.1371/journal.pone.0136111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 07/29/2015] [Indexed: 12/25/2022] Open
Abstract
Glutamate is the major excitatory neurotransmitter, but prolonged exposure even at micromolar concentrations causes neuronal death. Extracellular glutamate is maintained at nanomolar level by glutamate transporters, which, however, may reverse transport and release glutamate. If and when the reverse occurs depends on glutamate transport stoichiometry (GTS). Previously we found that in the presence of chloride, the coupled GLT-1 glutamate transporter current and its relationship to radiolabeled glutamate flux significantly decreased when extracellular glutamate concentration increased above 0.2 mM, which implies a change in GTS. Such high concentrations are feasible near GLT-1 expressed close to synaptic release site during excitatory neurotransmission. The aim of this study was to determine GLT-1 GTS at both low (19–75 μM) and high (300–1200 μM) glutamate concentration ranges. GTS experiments were conducted in the absence of chloride to avoid contributions by the GLT-1 uncoupled chloride conductance. Mathematical analysis of the transporter thermodynamic equilibrium allowed us to derive equations revealing the number of a particular type of ion transported per elementary charge based on the measurements of the transporter reversal potential. We found that GLT-1a expressed in COS-7 cells co-transports 1.5 Na+, 0.5 Glu-, 0.5 H+ and counter-transports 0.6 K+ per elementary charge in both glutamate concentration ranges, and at both 37°C and 26°C temperatures. The thermodynamic parameter Q10 = 2.4 for GLT-1 turnover rate of 19 s-1 (37°C, -50 mV) remained constant in the 10 μM–10 mM glutamate concentration range. Importantly, the previously reported decrease in the current/flux ratio at high glutamate concentration was not seen in the absence of chloride in both COS-7 cells and cultured rat neurons. Therefore, only in the absence of chloride, GLT-1 GTS remains constant at all glutamate concentrations. Possible explanations for why apparent GTS might vary in the presence of chloride are discussed.
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Feng D, Guo B, Liu G, Wang B, Wang W, Gao G, Qin H, Wu S. FGF2 alleviates PTSD symptoms in rats by restoring GLAST function in astrocytes via the JAK/STAT pathway. Eur Neuropsychopharmacol 2015; 25:1287-99. [PMID: 25979764 DOI: 10.1016/j.euroneuro.2015.04.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Revised: 04/06/2015] [Accepted: 04/24/2015] [Indexed: 12/18/2022]
Abstract
In our previous study, we demonstrated that fibroblast growth factor 2 (FGF2) administration alleviated posttraumatic stress disorder (PTSD) symptoms via an "astrocyte-related" mechanism. We further investigated the changes in the astrocytic glutamate transporters GLAST and GLT-1 and in JAK/STAT3 signaling (which is involved in astrocyte activation and GLAST/GLT-1 function) in single prolonged stress (SPS) model rats. High-performance liquid chromatography (HPLC), Western blot and immunohistochemistry analyses revealed a significant SPS-induced increase in the concentration of glutamate in the cerebrospinal fluid and decrease in GLAST/GLT-1 expression and JAK/STAT3 signaling. Treatment with FGF2 significantly alleviated GLAST/GLT-1 dysfunction, JAK/STAT3 signaling inhibition, and the behavioral abnormalities. The administration of the JAK/STAT pathway inhibitor AG490 blocked the effects of FGF2 on PTSD symptoms, astrocyte activation, and GLAST, but not GLT-1, expression in vivo and in vitro. Our findings suggest that astrocytic JAK/STAT signaling is associated with SPS-induced GLAST dysfunction and that FGF2 protects against PTSD symptoms by restoring astrocytic glutamate uptake via the JAK/STAT signaling pathway.
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Affiliation(s)
- Dayun Feng
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, Fourth Military Medical University, Xi'an 710032, PR China; Department of Neurosurgery and Institute for Functional Brain Disorders, Tangdu Hospital, Fourth Military Medical University, Xi'an 710032, PR China
| | - Baolin Guo
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, Fourth Military Medical University, Xi'an 710032, PR China
| | - Gaohua Liu
- Department of Psychosomatics, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, PR China
| | - Bao Wang
- Department of Neurosurgery and Institute for Functional Brain Disorders, Tangdu Hospital, Fourth Military Medical University, Xi'an 710032, PR China
| | - Wen Wang
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, Fourth Military Medical University, Xi'an 710032, PR China
| | - Guodong Gao
- Department of Neurosurgery and Institute for Functional Brain Disorders, Tangdu Hospital, Fourth Military Medical University, Xi'an 710032, PR China
| | - Huaizhou Qin
- Department of Neurosurgery and Institute for Functional Brain Disorders, Tangdu Hospital, Fourth Military Medical University, Xi'an 710032, PR China.
| | - Shengxi Wu
- Department of Neurobiology and Collaborative Innovation Center for Brain Science, Fourth Military Medical University, Xi'an 710032, PR China.
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Rudy CC, Hunsberger HC, Weitzner DS, Reed MN. The role of the tripartite glutamatergic synapse in the pathophysiology of Alzheimer's disease. Aging Dis 2015; 6:131-48. [PMID: 25821641 PMCID: PMC4365957 DOI: 10.14336/ad.2014.0423] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 04/23/2014] [Indexed: 12/26/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia in individuals over 65 years of age and is characterized by accumulation of beta-amyloid (Aβ) and tau. Both Aβ and tau alter synaptic plasticity, leading to synapse loss, neural network dysfunction, and eventually neuron loss. However, the exact mechanism by which these proteins cause neurodegeneration is still not clear. A growing body of evidence suggests perturbations in the glutamatergic tripartite synapse, comprised of a presynaptic terminal, a postsynaptic spine, and an astrocytic process, may underlie the pathogenic mechanisms of AD. Glutamate is the primary excitatory neurotransmitter in the brain and plays an important role in learning and memory, but alterations in glutamatergic signaling can lead to excitotoxicity. This review discusses the ways in which both beta-amyloid (Aβ) and tau act alone and in concert to perturb synaptic functioning of the tripartite synapse, including alterations in glutamate release, astrocytic uptake, and receptor signaling. Particular emphasis is given to the role of N-methyl-D-aspartate (NMDA) as a possible convergence point for Aβ and tau toxicity.
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Affiliation(s)
- Carolyn C. Rudy
- Behavioral Neuroscience, Department of Psychology, West Virginia University, Morgantown, WV, 26506, USA
| | - Holly C. Hunsberger
- Behavioral Neuroscience, Department of Psychology, West Virginia University, Morgantown, WV, 26506, USA
| | - Daniel S. Weitzner
- Behavioral Neuroscience, Department of Psychology, West Virginia University, Morgantown, WV, 26506, USA
| | - Miranda N. Reed
- Behavioral Neuroscience, Department of Psychology, West Virginia University, Morgantown, WV, 26506, USA
- Center for Neuroscience, West Virginia University, Morgantown, WV, 26506, USA
- Center for Basic and Translational Stroke Research, West Virginia University, Morgantown, WV, 26506, USA
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Abstract
PURPOSE OF REVIEW The literature on the influence of dietary omega-3 polyunsaturated fatty acid (ω-3 PUFA) on brain aging has grown exponentially during the last decade. Many avenues have been explored but no global picture or clear evidence has emerged. Experimental studies have shown that ω-3 PUFA is involved in many neurobiological processes that are involved in neurotransmission and neuroprotection, indicating that these PUFAs may prevent age-related brain damage. Human studies have revealed only a weak link between ω-3 PUFA status and cognitive aging, whereas interventional studies have yet to confirm it. The purpose of this review is to analyze the developments in the area during the last 2 years. RECENT FINDINGS Human brain MRI studies have confirmed previous findings that ω-3 PUFA can protect the brain during aging; two intervention studies obtained clear evidence. We also analyzed the experimental data clarifying the involvement of ω-3 PUFA in neurotransmission, neuroprotection (including prevention of peroxidation, inflammation, and excitotoxicity), and neurogenesis, thereby helping the brain cope with aging. SUMMARY These recent human and experimental studies provide support for and clarification of how ω-3 PUFA protect against brain aging and highlight the main lines for future research.
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Affiliation(s)
- Isabelle Denis
- aUnité de Neurobiologie de l'Olfaction, NBO U1197, INRA, Jouy-en-Josas bINSERM UMR 894, Centre de Psychiatrie et Neurosciences, Paris cUnité MICALIS, UMR 1319, INRA, Jouy-en-Josas dUnité NutriNeurO, UMR INRA 1286, Université Victor Segalen Bordeaux 2, Bordeaux, France
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Kervern M, Silvestre de Ferron B, Alaux-Cantin S, Fedorenko O, Antol J, Naassila M, Pierrefiche O. Aberrant NMDA-dependent LTD after perinatal ethanol exposure in young adult rat hippocampus. Hippocampus 2015; 25:912-23. [PMID: 25581546 DOI: 10.1002/hipo.22414] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2015] [Indexed: 12/29/2022]
Abstract
Irreversible cognitive deficits induced by ethanol exposure during fetal life have been ascribed to a lower NMDA-dependent synaptic long-term potentiation (LTP) in the hippocampus. Whether NMDA-dependent long-term depression (LTD) may also play a critical role in those deficits remains unknown. Here, we show that in vitro LTD induced with paired-pulse low frequency stimulation is enhanced in CA1 hippocampus field of young adult rats exposed to ethanol during brain development. Furthermore, single pulse low frequency stimulation, ineffective at this age (LFS600), induced LTD after ethanol exposure accompanied with a stronger response than controls during LFS600, thus revealing an aberrant form of activity-dependent plasticity at this age. Blocking NMDA receptor or GluN2B containing NMDA receptor prevented both the stronger response during LFS600 and LTD whereas Zinc, an antagonist of GluN2A containing NMDA receptor, was ineffective on both responses. In addition, LFS600-induced LTD was revealed in controls only with a reduced-Mg(2+) medium. In whole dissected hippocampus CA1 field, perinatal ethanol exposure increased GluN2B subunit expression in the synaptic compartment whereas GluN2A was unaltered. Using pharmacological tools, we suggest that LFS600 LTD was of synaptic origin. Altogether, we describe a new mechanism by which ethanol exposure during fetal life induces a long-term alteration of synaptic plasticity involving NMDA receptors, leading to an aberrant LTD. We suggest this effect of ethanol may reflect a delayed maturation of the synapse and that aberrant LTD may also participates to long-lasting cognitive deficits in fetal alcohol spectrum disorder.
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Affiliation(s)
| | | | | | | | | | | | - Olivier Pierrefiche
- INSERM ERi 24 - GRAP, Groupe de Recherche sur l'Alcool et les Pharmacodépendances, C.U.R.S., UPJV, Amiens, France
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Glutamatergic regulation prevents hippocampal-dependent age-related cognitive decline through dendritic spine clustering. Proc Natl Acad Sci U S A 2014; 111:18733-8. [PMID: 25512503 DOI: 10.1073/pnas.1421285111] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The dementia of Alzheimer's disease (AD) results primarily from degeneration of neurons that furnish glutamatergic corticocortical connections that subserve cognition. Although neuron death is minimal in the absence of AD, age-related cognitive decline does occur in animals as well as humans, and it decreases quality of life for elderly people. Age-related cognitive decline has been linked to synapse loss and/or alterations of synaptic proteins that impair function in regions such as the hippocampus and prefrontal cortex. These synaptic alterations are likely reversible, such that maintenance of synaptic health in the face of aging is a critically important therapeutic goal. Here, we show that riluzole can protect against some of the synaptic alterations in hippocampus that are linked to age-related memory loss in rats. Riluzole increases glutamate uptake through glial transporters and is thought to decrease glutamate spillover to extrasynaptic NMDA receptors while increasing synaptic glutamatergic activity. Treated aged rats were protected against age-related cognitive decline displayed in nontreated aged animals. Memory performance correlated with density of thin spines on apical dendrites in CA1, although not with mushroom spines. Furthermore, riluzole-treated rats had an increase in clustering of thin spines that correlated with memory performance and was specific to the apical, but not the basilar, dendrites of CA1. Clustering of synaptic inputs is thought to allow nonlinear summation of synaptic strength. These findings further elucidate neuroplastic changes in glutamatergic circuits with aging and advance therapeutic development to prevent and treat age-related cognitive decline.
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Stephens ML, Williamson A, Deel ME, Bensalem-Owen M, Davis VA, Slevin J, Pomerleau F, Huettl P, Gerhardt GA. Tonic glutamate in CA1 of aging rats correlates with phasic glutamate dysregulation during seizure. Epilepsia 2014; 55:1817-25. [PMID: 25266171 DOI: 10.1111/epi.12797] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2014] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Characterize glutamate neurotransmission in the hippocampus of awake-behaving rodents during focal seizures in a model of aging. METHODS We used enzyme-based ceramic microelectrode array technology to measure in vivo extracellular tonic glutamate levels and real-time phasic glutamate release and clearance events in the hippocampus of awake Fischer 344 rats. Local application of 4-aminopyridine (4-AP) into the CA1 region was used to induce focal motor seizures in different animal age groups representing young, late-middle aged and elderly humans. RESULTS Rats with the highest preseizure tonic glutamate levels (all in late-middle aged or elderly groups) experienced the most persistent 4-AP-induced focal seizure motor activity (wet dog shakes) and greatest degree of acute seizure-associated disruption of glutamate neurotransmission measured as rapid transient changes in extracellular glutamate levels. SIGNIFICANCE Increased seizure susceptibility was demonstrated in the rats with the highest baseline hippocampal extracellular glutamate levels, all of which were late-middle aged or aged animals. The manifestation of seizures behaviorally was associated with dynamic changes in glutamate neurotransmission. To our knowledge, this is the first report of a relationship between seizure susceptibility and alterations in both baseline tonic and phasic glutamate neurotransmission.
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Affiliation(s)
- Michelle L Stephens
- Department of Anesthesiology, The Ohio State University Wexner Medical Center, Columbus, Ohio, U.S.A
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Wang ZC, Zhao J, Li S. Dysregulation of synaptic and extrasynaptic N-methyl-D-aspartate receptors induced by amyloid-β. Neurosci Bull 2013; 29:752-60. [PMID: 24136243 DOI: 10.1007/s12264-013-1383-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Accepted: 02/25/2013] [Indexed: 02/07/2023] Open
Abstract
The toxicity of amyloid-beta (Aβ) is strongly associated with Alzheimer's disease (AD), which has a high incidence in the elderly worldwide. Recent evidence showed that alteration in the activity of N-methyl-D-aspartate receptors (NMDARs) plays a key role in Aβ-induced neurotoxicity. However, the activation of synaptic and extrasynaptic NMDARs has distinct consequences for plasticity, gene regulation, neuronal death, and Aβ production. This review focuses on the dysregulation of synaptic and extrasynaptic NMDARs induced by Aβ. On one hand, Aβ downregulates the synaptic NMDAR response by promoting NMDAR endocytosis, leading to either neurotoxicity or neuroprotection. On the other hand, Aβ enhances the activation of extrasynaptic NMDARs by decreasing neuronal glutamate uptake and inducing glutamate spillover, subsequently causing neurotoxicity. In addition, selective enhancement of synaptic activity by low doses of NMDA, or reduction of extrasynaptic activity by memantine, a non-competitive NMDAR antagonist, halts Aβ-induced neurotoxicity. Therefore, future neuroprotective drugs for AD should aim at both the enhancement of synaptic activity and the disruption of extrasynaptic NMDAR-dependent death signaling.
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Affiliation(s)
- Zhi-Cong Wang
- Department of Physiology, Dalian Medical University, Dalian, 116044, China
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Brothers HM, Bardou I, Hopp SC, Kaercher RM, Corona AW, Fenn AM, Godbout JP, Wenk GL. Riluzole partially rescues age-associated, but not LPS-induced, loss of glutamate transporters and spatial memory. J Neuroimmune Pharmacol 2013; 8:1098-105. [PMID: 23709339 DOI: 10.1007/s11481-013-9476-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 05/15/2013] [Indexed: 01/22/2023]
Abstract
Impaired memory may result from synaptic glutamatergic dysregulation related to chronic neuroinflammation. GLT1 is the primary excitatory amino acid transporter responsible for regulating extracellular glutamate levels in the hippocampus. We tested the hypothesis that if impaired spatial memory results from increased extracellular glutamate due to age or experimentally induced chronic neuroinflammation in the hippocampus, then pharmacological augmentation of the glutamate transporter GLT1 will attenuate deficits in a hippocampal-dependent spatial memory task. The profile of inflammation-related genes and proteins associated with normal aging, or chronic neuroinflammation experimentally-induced via a four-week LPS infusion into the IV(th) ventricle, were correlated with performance in the Morris water maze following treatment with Riluzole, a drug that can enhance glutamate clearance by increasing GLT1 expression. Age-associated inflammation was qualitatively different from LPS-induced neuro-inflammation in young rats. LPS produced a pro-inflammatory phenotype characterized by increased IL-1ß expression in the hippocampus, whereas aging was not associated with a strong central pro-inflammatory response but with a mixed peripheral immune phenotype. Riluzole attenuated the spatial memory impairment, the elevation of serum cytokines and the decrease in GLT1 gene expression in Aged rats, but had no effect on young rats infused with LPS. Our findings highlight the therapeutic potential of reducing glutamatergic function upon memory impairment in neurodegenerative diseases associated with aging.
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Affiliation(s)
- Holly M Brothers
- Department of Psychology, Ohio State University, 1835 Neil Avenue, Columbus, OH, 43210, USA
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