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Kim H, Choi S, Lee E, Koh W, Lee CJ. Tonic NMDA Receptor Currents in the Brain: Regulation and Cognitive Functions. Biol Psychiatry 2024; 96:164-175. [PMID: 38490367 DOI: 10.1016/j.biopsych.2024.03.009] [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: 10/24/2023] [Revised: 02/20/2024] [Accepted: 03/04/2024] [Indexed: 03/17/2024]
Abstract
Synaptically localized NMDA receptors (NMDARs) play a crucial role in important cognitive functions by mediating synaptic transmission and plasticity. In contrast, a tonic NMDAR current, thought to be mediated by extrasynaptic NMDARs, has a less clear function. This review provides a comprehensive overview of tonic NMDAR currents, focusing on their roles in synaptic transmission/plasticity and their impact on cognitive functions and psychiatric disorders. We discuss the roles of 3 endogenous ligands (i.e., glutamate, glycine, and D-serine) and receptors in mediating tonic NMDAR currents and explore the diverse mechanisms that regulate tonic NMDAR currents. In light of recent controversies surrounding the source of D-serine, we highlight the recent findings suggesting that astrocytes release D-serine to modulate tonic NMDAR currents and control cognitive flexibility. Furthermore, we propose distinct roles of neuronal and astrocytic D-serine in different locations and their implications for synaptic regulation and cognitive functions. The potential roles of tonic NMDAR currents in various psychiatric disorders, such as schizophrenia and autism spectrum disorder, are discussed in the context of the NMDAR hypofunction hypothesis. By presenting the mechanisms by which various cells, particularly astrocytes, regulate tonic NMDAR currents, we aim to stimulate future research in NMDAR hypofunction- or hyperfunction-related psychiatric disorders. This review not only provides a better understanding of the complex interplay between tonic NMDAR currents and cognitive functions but also sheds light on its potential therapeutic target for the treatment of various psychiatric disorders.
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Affiliation(s)
- Hayoung Kim
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science, Daejeon, South Korea
| | - Sunyeong Choi
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science, Daejeon, South Korea
| | - Euisun Lee
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science, Daejeon, South Korea
| | - Wuhyun Koh
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science, Daejeon, South Korea.
| | - C Justin Lee
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science, Daejeon, South Korea.
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2
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Bean L, Bose PK, Rani A, Kumar A. Serine racemase expression profile in the prefrontal cortex and hippocampal subregions during aging in male and female rats. Aging (Albany NY) 2024; 16:8402-8416. [PMID: 38761177 PMCID: PMC11164512 DOI: 10.18632/aging.205841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 04/10/2024] [Indexed: 05/20/2024]
Abstract
Aging is associated with a decrease in N-methyl-D-aspartate (NMDA) receptor function, which is critical for maintaining synaptic plasticity, learning, and memory. Activation of the NMDA receptor requires binding of the neurotransmitter glutamate and also the presence of co-agonist D-serine at the glycine site. The enzymatic conversion of L-serine to D-serine is facilitated by the enzyme serine racemase (SR). Subsequently, SR plays a pivotal role in regulating NMDA receptor activity, thereby impacting synaptic plasticity and memory processes in the central nervous system. As such, age-related changes in the expression of SR could contribute to decreased NMDA receptor function. However, age-associated changes in SR expression levels in the medial and lateral prefrontal cortex (mPFC, lPFC), and in the dorsal hippocampal subfields, CA1, CA3, and dentate gyrus (DG), have not been thoroughly elucidated. Therefore, the current studies were designed to determine the SR expression profile, including protein levels and mRNA, for these regions in aged and young male and female Fischer-344 rats. Our results demonstrate a significant reduction in SR expression levels in the mPFC and all hippocampal subfields of aged rats compared to young rats. No sex differences were observed in the expression of SR. These findings suggest that the decrease in SR levels may play a role in the age-associated reduction of NMDA receptor function in brain regions crucial for cognitive function and synaptic plasticity.
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Affiliation(s)
- Linda Bean
- Department of Anatomy, Cell Biology, and Physiology, IU School of Medicine, Indianapolis, IN 46201, USA
| | - Prodip K. Bose
- Brain Rehabilitation Research Center, Malcom Randall Department of Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32607, USA
- Department of Anesthesiology and Department of Neurology at the College of Medicine, University of Florida, FL 32607, USA
| | - Asha Rani
- Department of Neuroscience, The McKnight Brain Institute, University of Florida, Gainesville, FL 32607, USA
| | - Ashok Kumar
- Department of Neuroscience, The McKnight Brain Institute, University of Florida, Gainesville, FL 32607, USA
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3
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Abreu DS, Gomes JI, Ribeiro FF, Diógenes MJ, Sebastião AM, Vaz SH. Astrocytes control hippocampal synaptic plasticity through the vesicular-dependent release of D-serine. Front Cell Neurosci 2023; 17:1282841. [PMID: 38145284 PMCID: PMC10740624 DOI: 10.3389/fncel.2023.1282841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 11/10/2023] [Indexed: 12/26/2023] Open
Abstract
Astrocytes, the most abundant glial cells in the central nervous system (CNS), sense synaptic activity and respond through the release of gliotransmitters, a process mediated by intracellular Ca2+ level changes and SNARE-dependent mechanisms. Ionotropic N-methyl-D-aspartate (NMDA) receptors, which are activated by glutamate along with D-serine or glycine, play a crucial role in learning, memory, and synaptic plasticity. However, the precise impact of astrocyte-released D-serine on neuronal modulation remains insufficiently characterized. To address this, we have used the dominant negative SNARE (dnSNARE) mouse model, which selectively inhibits SNARE-dependent exocytosis from astrocytes. We recorded field excitatory postsynaptic potentials (fEPSPs) in CA3-CA1 synapses within hippocampal slices obtained from dnSNARE mice and wild-type (Wt) littermates. Our results demonstrate that hippocampal θ-burst long-term potentiation (LTP), a critical form of synaptic plasticity, is impaired in hippocampal slices from dnSNARE mice. Notably, this LTP impairment was rescued upon incubation with D-serine. To further investigate the involvement of astrocytes in D-serine-mediated mechanisms of LTP maintenance, we perfused hippocampal slices with L-serine - a substrate used by both neurons and astrocytes for D-serine production. The enhancement in LTP observed in dnSNARE mice was exclusively associated with D-serine presence, with no effects evident in the presence of L-serine. Additionally, both D- and L-serine reduced basal synaptic strength in the hippocampal slices of both Wt and dnSNARE mice. These results provide compelling evidence that distinct processes underlie the modulation of basal synaptic transmission and LTP through D-serine. Our findings underscore the pivotal contribution of astrocytes in D-serine-mediated processes that govern LTP establishment and basal transmission. This study not only provides essential insights into the intricate interplay between neurons and astrocytes but also emphasizes their collective role in shaping hippocampal synaptic function.
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Affiliation(s)
- Daniela Sofia Abreu
- Faculdade de Medicina, Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisbon, Portugal
- Faculdade de Medicina, Instituto de Farmacologia e Neurociências, Universidade de Lisboa, Lisbon, Portugal
| | - Joana I. Gomes
- Faculdade de Medicina, Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisbon, Portugal
- Faculdade de Medicina, Instituto de Farmacologia e Neurociências, Universidade de Lisboa, Lisbon, Portugal
| | - Filipa F. Ribeiro
- Faculdade de Medicina, Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisbon, Portugal
- Faculdade de Medicina, Instituto de Farmacologia e Neurociências, Universidade de Lisboa, Lisbon, Portugal
| | - Maria J. Diógenes
- Faculdade de Medicina, Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisbon, Portugal
- Faculdade de Medicina, Instituto de Farmacologia e Neurociências, Universidade de Lisboa, Lisbon, Portugal
| | - Ana M. Sebastião
- Faculdade de Medicina, Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisbon, Portugal
- Faculdade de Medicina, Instituto de Farmacologia e Neurociências, Universidade de Lisboa, Lisbon, Portugal
| | - Sandra H. Vaz
- Faculdade de Medicina, Instituto de Medicina Molecular João Lobo Antunes, Universidade de Lisboa, Lisbon, Portugal
- Faculdade de Medicina, Instituto de Farmacologia e Neurociências, Universidade de Lisboa, Lisbon, Portugal
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Sugiyama E, Nishiya Y, Yamashita K, Hirokawa R, Iinuma Y, Nirasawa T, Mizuno H, Hamashima Y, Todoroki K. Charged chiral derivatization for enantioselective imaging of D-,L-2-hydroxyglutaric acid using ion mobility spectrometry/mass spectrometry. Chem Commun (Camb) 2023; 59:10916-10919. [PMID: 37606059 DOI: 10.1039/d3cc01963b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
A newly synthesized charged chiral tag-enabled enantioselective imaging of D-,L-2-hydroxyglutaric acid, which are independently associated with the regulation of DNA methylation. The tag-conjugated diastereomers were ionized efficiently through MALDI, separated by ion mobility spectrometry, and further separated from other molecules in mass spectrometry. On-tissue chiral derivatization using the tag facilitated the visualization of different distributions of the two isomers in the mouse testis.
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Affiliation(s)
- Eiji Sugiyama
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
| | - Yuki Nishiya
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
| | - Kenji Yamashita
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
| | - Ryo Hirokawa
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
| | - Yoshiteru Iinuma
- Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Takashi Nirasawa
- Daltonics Division, Bruker Japan K.K., Moriyacho Kanagawa-ku, Yokohama-shi, Kanagawa 221-0022, Japan
| | - Hajime Mizuno
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
- Laboratory of Analytical Chemistry, Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku, Nagoya, 468-8503, Japan
| | - Yoshitaka Hamashima
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
| | - Kenichiro Todoroki
- School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka, 422-8526, Japan.
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Vershinina YS, Krasnov GS, Garbuz DG, Shaposhnikov MV, Fedorova MS, Pudova EA, Katunina IV, Kornev AB, Zemskaya NV, Kudryavtsev AA, Bulavkina EV, Matveeva AA, Ulyasheva NS, Guvatova ZG, Anurov AA, Moskalev AA, Kudryavtseva AV. Transcriptomic Analysis of the Effect of Torin-2 on the Central Nervous System of Drosophila melanogaster. Int J Mol Sci 2023; 24:ijms24109095. [PMID: 37240439 DOI: 10.3390/ijms24109095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/24/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
Torin-2, a synthetic compound, is a highly selective inhibitor of both TORC1 and TORC2 (target of rapamycin) complexes as an alternative to the well-known immunosuppressor, geroprotector, and potential anti-cancer natural compound rapamycin. Torin-2 is effective at hundreds of times lower concentrations and prevents some negative side effects of rapamycin. Moreover, it inhibits the rapamycin-resistant TORC2 complex. In this work, we evaluated transcriptomic changes in D. melanogaster heads induced with lifetime diets containing Torin-2 and suggested possible neuroprotective mechanisms of Torin-2. The analysis included D. melanogaster of three ages (2, 4, and 6 weeks old), separately for males and females. Torin-2, taken at the lowest concentration being tested (0.5 μM per 1 L of nutrient paste), had a slight positive effect on the lifespan of D. melanogaster males (+4% on the average) and no positive effect on females. At the same time, RNA-Seq analysis revealed interesting and previously undiscussed effects of Torin-2, which differed between sexes as well as in flies of different ages. Among the cellular pathways mostly altered by Torin-2 at the gene expression level, we identified immune response, protein folding (heat shock proteins), histone modification, actin cytoskeleton organization, phototransduction and sexual behavior. Additionally, we revealed that Torin-2 predominantly reduced the expression of Srr gene responsible for the conversion of L-serine to D-serine and thus regulating activity of NMDA receptor. Via western blot analysis, we showed than in old males Torin-2 tends to increase the ratio of the active phosphorylated form of ERK, the lowest node of the MAPK cascade, which may play a significant role in neuroprotection. Thus, the complex effect of Torin-2 may be due to the interplay of the immune system, hormonal background, and metabolism. Our work is of interest for further research in the field of NMDA-mediated neurodegeneration.
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Affiliation(s)
- Yulia S Vershinina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - George S Krasnov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - David G Garbuz
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | | | - Maria S Fedorova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Elena A Pudova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Irina V Katunina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Alexey B Kornev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Nadezhda V Zemskaya
- Institute of Biology, Komi Science Center, Ural Branch of RAS, 167000 Syktyvkar, Russia
| | - Alexander A Kudryavtsev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Elizaveta V Bulavkina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Anna A Matveeva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Natalia S Ulyasheva
- Institute of Biology, Komi Science Center, Ural Branch of RAS, 167000 Syktyvkar, Russia
| | - Zulfiya G Guvatova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Artemiy A Anurov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Alexey A Moskalev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Anna V Kudryavtseva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
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6
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Yegla B, Rani A, Kumar A. Viral vector-mediated upregulation of serine racemase expression in medial prefrontal cortex improves learning and synaptic function in middle age rats. Aging (Albany NY) 2023; 15:2433-2449. [PMID: 37052995 PMCID: PMC10120901 DOI: 10.18632/aging.204652] [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: 01/19/2023] [Accepted: 04/03/2023] [Indexed: 04/14/2023]
Abstract
An age-associated decrease in N-methyl-D-aspartate receptor (NMDAR)-mediated synaptic function contributes to impaired synaptic plasticity and is associated with cognitive impairments. Levels of serine racemase (SR), an enzyme that synthesizes D-serine, an NMDAR co-agonist, decline with age. Thus, enhancing NMDAR function via increased SR expression in middle age, when subtle declines in cognition emerge, was predicted to enhance performance on a prefrontal cortex-mediated task sensitive to aging. Middle-aged (~12 mo) male Fischer-344 rats were injected bilaterally in the medial prefrontal cortex (mPFC) with viral vector (LV), SR (LV-SR) or control (LV-GFP). Rats were trained on the operant attentional set-shift task (AST) to examine cognitive flexibility and attentional function. LV-SR rats exhibited a faster rate of learning compared to controls during visual discrimination of the AST. Extradimensional set shifting and reversal were not impacted. Immunohistochemical analyses demonstrated that LV-SR significantly increased SR expression in the mPFC. Electrophysiological characterization of synaptic transmission in the mPFC slices obtained from LV-GFP and LV-SR animals indicated a significant increase in isolated NMDAR-mediated synaptic responses in LV-SR slices. Thus, results of the current study demonstrated that prefrontal SR upregulation in middle age rats can improve learning of task contingencies for visual discrimination and increase glutamatergic synaptic transmission, including NMDAR activity.
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Affiliation(s)
- Brittney Yegla
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Asha Rani
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
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7
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Caldwell M, Hughes M, Wei F, Ngo C, Pascua R, Pugazhendhi AS, Coathup MJ. Promising applications of D-amino acids in periprosthetic joint infection. Bone Res 2023; 11:14. [PMID: 36894568 PMCID: PMC9998894 DOI: 10.1038/s41413-023-00254-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 02/02/2023] [Accepted: 02/10/2023] [Indexed: 03/11/2023] Open
Abstract
Due to the rise in our aging population, a disproportionate demand for total joint arthroplasty (TJA) in the elderly is forecast. Periprosthetic joint infection (PJI) represents one of the most challenging complications that can occur following TJA, and as the number of primary and revision TJAs continues to rise, an increasing PJI burden is projected. Despite advances in operating room sterility, antiseptic protocols, and surgical techniques, approaches to prevent and treat PJI remain difficult, primarily due to the formation of microbial biofilms. This difficulty motivates researchers to continue searching for an effective antimicrobial strategy. The dextrorotatory-isoforms of amino acids (D-AAs) are essential components of peptidoglycan within the bacterial cell wall, providing strength and structural integrity in a diverse range of species. Among many tasks, D-AAs regulate cell morphology, spore germination, and bacterial survival, evasion, subversion, and adhesion in the host immune system. When administered exogenously, accumulating data have demonstrated that D-AAs play a pivotal role against bacterial adhesion to abiotic surfaces and subsequent biofilm formation; furthermore, D-AAs have substantial efficacy in promoting biofilm disassembly. This presents D-AAs as promising and novel targets for future therapeutic approaches. Despite their emerging antibacterial efficacy, their role in disrupting PJI biofilm formation, the disassembly of established TJA biofilm, and the host bone tissue response remains largely unexplored. This review aims to examine the role of D-AAs in the context of TJAs. Data to date suggest that D-AA bioengineering may serve as a promising future strategy in the prevention and treatment of PJI.
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Affiliation(s)
- Matthew Caldwell
- Biionix Cluster & College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA
| | - Megan Hughes
- School of Biosciences, Cardiff University, CF10 3AT, Wales, UK
| | - Fei Wei
- Biionix Cluster & College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA
| | - Christopher Ngo
- Biionix Cluster & College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA
| | - Raven Pascua
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA
| | - Abinaya Sindu Pugazhendhi
- Biionix Cluster & College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA
| | - Melanie J Coathup
- Biionix Cluster & College of Medicine, University of Central Florida, 6900 Lake Nona Blvd, Orlando, FL, 32827, USA.
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8
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Wu S, Zhou J, Zhang H, Barger SW. Serine Racemase Expression Differentiates Aging from Alzheimer's Brain. Curr Alzheimer Res 2022; 19:494-502. [PMID: 35929621 DOI: 10.2174/1567205019666220805105106] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 01/27/2023]
Abstract
Aging is an inevitable process characterized by progressive loss of physiological integrity and increased susceptibility to cancer, diabetes, cardiovascular, and neurodegenerative diseases; aging is the primary risk factor for Alzheimer's disease (AD), the most common cause of dementia. AD is characterized by brain pathology, including extracellular deposition of amyloid aggregation and intracellular accumulation of neurofibrillary tangles composed of hyperphosphorylated tau protein. In addition, losses of synapses and a wide range of neurons are pivotal pathologies in the AD brain. Accumulating evidence demonstrates hypoactivation of hippocampal neural networks in the aging brain, whereas AD-related mild cognitive impairment (AD-MCI) begins with hyperactivation, followed by a diminution of hippocampal activity as AD develops. The biphasic trends of the activity of the hippocampal neural network are consistent with the alteration of N-methyl-D-aspartate receptor (NMDA-R) activity from aging to prodromal (AD-MCI) to mid-/late stage AD. D-serine, a product of racemization catalyzed by serine racemase (SR), is an important co-agonist of the NMDA-R which is involved in synaptic events including neurotransmission, synaptogenesis, long-term potentiation (LTP), development, and excitotoxicity. SR and D-serine are decreased in the hippocampus of the aging brain, correlating with impairment of cognitive function. By contrast, SR is increased in AD brain, which is associated with a greater degree of cognitive dysfunction. Emerging studies suggest that D-serine levels in the brain or in cerebral spinal fluid from AD patients are higher than in age-matched controls, but the results are inconsistent. Very recently, serum D-serine levels in AD were reported to correlate with sex and clinical dementia rating (CDR) stage. This review will discuss alterations of NMDA-R and SR in aging and AD brain, and the mechanisms underlying the differential regulation of SR will be probed. Collectively, we propose that SR may be a molecular switch that distinguishes the effects of aging from those of AD on the brain.
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Affiliation(s)
- Shengzhou Wu
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, State Key Laboratory of Optometry, Wenzhou, Zhejiang 325003, P.R. China
| | - Jing Zhou
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, State Key Laboratory of Optometry, Wenzhou, Zhejiang 325003, P.R. China
| | - He Zhang
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, State Key Laboratory of Optometry, Wenzhou, Zhejiang 325003, P.R. China.,College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang, P.R. China
| | - Steven W Barger
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock AR, USA.,Geriatric Research, Education & Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock AR, USA
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9
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Umino A, Iwama H, Umino M, Shimazu D, Kiuchi Y, Nishikawa T. Effects of Quinolinate-Induced Lesion of the Medial Prefrontal Cortex on Prefrontal and Striatal Concentrations of D-Serine in the Rat. Neurochem Res 2022; 47:2728-2740. [PMID: 35604516 DOI: 10.1007/s11064-022-03627-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 04/19/2022] [Accepted: 05/05/2022] [Indexed: 11/28/2022]
Abstract
D-Serine has been shown to play an important role in the expression and control of a variety of brain functions by acting as the endogenous coagonist for the N-methyl-D-aspartate type glutamate receptor (NMDAR), at least, in the forebrain. To obtain further insight into the still debatable cellular localization of the D-amino acid, we have examined the effects of the selective destruction of the neuronal cell bodies by quinolinate on the tissue or extracellular D-serine concentrations in the medial prefrontal cortex of the rat. A local quinolinate infusion into the bilateral medial prefrontal cortex produced a cortical lesion with a marked (- 65%) and non-significant alteration (- 5%) in the cortical and striatal tissue D-serine concentrations, respectively, 7 days post-infusion. In vivo microdialysis experiments in the right prefrontal lesion site 9 days after the quinolinate application revealed that the basal extracellular D-serine levels were also dramatically reduced (- 64%). A prominent reduction in the tissue levels of GABA in the interneurons of the prefrontal cortex (- 78%) without significant changes in those in the striatum (+ 12%) verified that a major lesion part was confined to the cortical portion. The lack of a significant influence of the prefrontal quinolinate lesion on its dopamine concentrations in the mesocortical dopamine projections suggests that the nerve terminals and axons in the lesion site may be spared. These findings are consistent with the perikarya-selective nature of the present quinolinate-induced lesion and further support the view that neuronal cell bodies of intrinsic neurons in the prefrontal cortical region contain substantial amounts of D-serine, which may sustain the basal extracellular concentrations of D-serine.
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Affiliation(s)
- Asami Umino
- Department of Pharmacology, School of Medicine, and Pharmacological Research Center, Showa University, Shinagawa-ku, Tokyo, 142-8555, Japan.,Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, 113-8519, Japan.,Departments of Mental Disorder Research, National Institute of Neuroscience, NCNP, Kodaira-shi, Tokyo, 187-8502, Japan
| | - Hisayuki Iwama
- Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, 113-8519, Japan.,Departments of Mental Disorder Research, National Institute of Neuroscience, NCNP, Kodaira-shi, Tokyo, 187-8502, Japan.,Kanagawa Psychiatric Center, Yokohama-shi, Kanagawa, 233-0006, Japan
| | - Masakazu Umino
- Department of Pharmacology, School of Medicine, and Pharmacological Research Center, Showa University, Shinagawa-ku, Tokyo, 142-8555, Japan.,Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - Dai Shimazu
- Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, 113-8519, Japan.,Departments of Mental Disorder Research, National Institute of Neuroscience, NCNP, Kodaira-shi, Tokyo, 187-8502, Japan.,Musashishinjo-Kokorono Clinic, Kawasaki-shi, Kanagawa, 211-0044, Japan
| | - Yuji Kiuchi
- Department of Pharmacology, School of Medicine, and Pharmacological Research Center, Showa University, Shinagawa-ku, Tokyo, 142-8555, Japan
| | - Toru Nishikawa
- Department of Pharmacology, School of Medicine, and Pharmacological Research Center, Showa University, Shinagawa-ku, Tokyo, 142-8555, Japan. .,Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, 113-8519, Japan. .,Departments of Mental Disorder Research, National Institute of Neuroscience, NCNP, Kodaira-shi, Tokyo, 187-8502, Japan.
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10
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Tworig JM, Feller MB. Müller Glia in Retinal Development: From Specification to Circuit Integration. Front Neural Circuits 2022; 15:815923. [PMID: 35185477 PMCID: PMC8856507 DOI: 10.3389/fncir.2021.815923] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 12/23/2021] [Indexed: 01/21/2023] Open
Abstract
Müller glia of the retina share many features with astroglia located throughout the brain including maintenance of homeostasis, modulation of neurotransmitter spillover, and robust response to injury. Here we present the molecular factors and signaling events that govern Müller glial specification, patterning, and differentiation. Next, we discuss the various roles of Müller glia in retinal development, which include maintaining retinal organization and integrity as well as promoting neuronal survival, synaptogenesis, and phagocytosis of debris. Finally, we review the mechanisms by which Müller glia integrate into retinal circuits and actively participate in neuronal signaling during development.
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Affiliation(s)
- Joshua M. Tworig
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
- *Correspondence: Joshua M. Tworig,
| | - Marla B. Feller
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, United States
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11
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Modulation of Hippocampal Astroglial Activity by Synaptamide in Rats with Neuropathic Pain. Brain Sci 2021; 11:brainsci11121561. [PMID: 34942863 PMCID: PMC8699312 DOI: 10.3390/brainsci11121561] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 11/19/2021] [Accepted: 11/24/2021] [Indexed: 11/23/2022] Open
Abstract
The present study demonstrates that synaptamide (N-docosahexaenoylethanolamine), an endogenous metabolite of docosahexaenoic acid, when administered subcutaneously (4 mg/kg/day, 14 days), exhibits analgesic activity and promotes cognitive recovery in the rat sciatic nerve chronic constriction injury (CCI) model. We analyzed the dynamics of GFAP-positive astroglia and S100β-positive astroglia activity, the expression of nerve growth factor (NGF), and two subunits of the NMDA receptor (NMDAR1 and NMDAR2A) in the hippocampi of the experimental animals. Hippocampal neurogenesis was evaluated by immunohistochemical detection of DCX. Analysis of N-acylethanolamines in plasma and in the brain was performed using the liquid chromatography-mass spectrometry technique. In vitro and in vivo experiments show that synaptamide (1) reduces cold allodynia, (2) improves working memory and locomotor activity, (3) stabilizes neurogenesis and astroglial activity, (4) enhances the expression of NGF and NMDAR1, (5) increases the concentration of Ca2+ in astrocytes, and (6) increases the production of N-acylethanolamines. The results of the present study demonstrate that synaptamide affects the activity of hippocampal astroglia, resulting in faster recovery after CCI.
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12
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Astrocytic contribution to glutamate-related central respiratory chemoreception in vertebrates. Respir Physiol Neurobiol 2021; 294:103744. [PMID: 34302992 DOI: 10.1016/j.resp.2021.103744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/01/2021] [Accepted: 07/18/2021] [Indexed: 12/24/2022]
Abstract
Central respiratory chemoreceptors play a key role in the respiratory homeostasis by sensing CO2 and H+ in brain and activating the respiratory neural network. This ability of specific brain regions to respond to acidosis and hypercapnia is based on neuronal and glial mechanisms. Several decades ago, glutamatergic transmission was proposed to be involved as a main mechanism in central chemoreception. However, a complete identification of mechanism has been elusive. At the rostral medulla, chemosensitive neurons of the retrotrapezoid nucleus (RTN) are glutamatergic and they are stimulated by ATP released by RTN astrocytes in response to hypercapnia. In addition, recent findings show that caudal medullary astrocytes in brainstem can also contribute as CO2 and H+ sensors that release D-serine and glutamate, both gliotransmitters able to activate the respiratory neural network. In this review, we describe the mammalian astrocytic glutamatergic contribution to the central respiratory chemoreception trying to trace in vertebrates the emergence of several components involved in this process.
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13
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Sherwood MW, Oliet SHR, Panatier A. NMDARs, Coincidence Detectors of Astrocytic and Neuronal Activities. Int J Mol Sci 2021; 22:7258. [PMID: 34298875 PMCID: PMC8307462 DOI: 10.3390/ijms22147258] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/30/2021] [Accepted: 06/30/2021] [Indexed: 12/18/2022] Open
Abstract
Synaptic plasticity is an extensively studied cellular correlate of learning and memory in which NMDARs play a starring role. One of the most interesting features of NMDARs is their ability to act as a co-incident detector. It is unique amongst neurotransmitter receptors in this respect. Co-incident detection is possible because the opening of NMDARs requires membrane depolarisation and the binding of glutamate. Opening of NMDARs also requires a co-agonist. Although the dynamic regulation of glutamate and membrane depolarization have been well studied in coincident detection, the role of the co-agonist site is unexplored. It turns out that non-neuronal glial cells, astrocytes, regulate co-agonist availability, giving them the ability to influence synaptic plasticity. The unique morphology and spatial arrangement of astrocytes at the synaptic level affords them the capacity to sample and integrate information originating from unrelated synapses, regardless of any pre-synaptic and post-synaptic commonality. As astrocytes are classically considered slow responders, their influence at the synapse is widely recognized as modulatory. The aim herein is to reconsider the potential of astrocytes to participate directly in ongoing synaptic NMDAR activity and co-incident detection.
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Affiliation(s)
- Mark W. Sherwood
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France;
| | | | - Aude Panatier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France;
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14
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Beltrán-Matas P, Hartveit E, Veruki ML. Different glutamate sources and endogenous co-agonists activate extrasynaptic NMDA receptors on amacrine cells of the rod pathway microcircuit. Eur J Neurosci 2021; 54:4456-4474. [PMID: 34048091 DOI: 10.1111/ejn.15325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/09/2021] [Accepted: 05/23/2021] [Indexed: 12/17/2022]
Abstract
The NMDA receptors (NMDARs) expressed by AII and A17 amacrine cells, the two main inhibitory interneurons of the rod pathway microcircuit in the mammalian retina, are exclusively extrasynaptic, activated by ambient levels of glutamate, and molecularly distinct, with AII and A17 amacrines expressing GluN2B- and GluN2A-containing receptors, respectively. This important sensory microcircuit thus provides a unique model to study the activation and function of extrasynaptic NMDARs. Here, we investigated the sources of glutamate and the endogenous co-agonists (d-serine or glycine) that activate these distinct populations of NMDARs. With acute slices from rat retina, we used whole-cell voltage-clamp recording and measurement of current noise to monitor levels of NMDAR activity. Pre-incubation of retina with bafilomycin A1 (an inhibitor of neurotransmitter uptake into synaptic vesicles) abolished NMDAR-mediated noise in AII, but not A17 amacrines, suggesting a vesicular source of glutamate activates AII NMDARs, whereas a non-vesicular source activates A17 NMDARs. Pre-incubation of retina with l-methionine sulfoximine (an inhibitor of glutamine synthetase) also abolished NMDAR-mediated noise in AII, but not A17 amacrines, suggesting a neuronal source of glutamate activates AII NMDARs, whereas a glial source activates A17 NMDARs. Enzymatic breakdown of d-serine reduced NMDAR-mediated noise in AII, but not A17 amacrines, suggesting d-serine is the endogenous co-agonist at AII, but not A17 NMDARs. Our results reveal unique characteristics of these two populations of extrasynaptic NMDARs. The differential and independent activation of these receptors is likely to provide specific contributions to the signal processing and plasticity of the cellular components of the rod pathway microcircuit.
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Affiliation(s)
| | - Espen Hartveit
- Department of Biomedicine, University of Bergen, Bergen, Norway
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15
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TGFβ1-Smad3 signaling mediates the formation of a stable serine racemase dimer in microglia. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140447. [DOI: 10.1016/j.bbapap.2020.140447] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 05/14/2020] [Accepted: 05/17/2020] [Indexed: 12/13/2022]
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16
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Beltrán-Castillo S, Olivares MJ, Ochoa M, Barria J, Chacón M, von Bernhardi R, Eugenín J. d-serine regulation of the timing and architecture of the inspiratory burst in neonatal mice. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140484. [PMID: 32652125 DOI: 10.1016/j.bbapap.2020.140484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 06/08/2020] [Accepted: 06/30/2020] [Indexed: 10/23/2022]
Abstract
d-serine, released from mouse medullary astrocytes in response to increased CO2 levels, boosts the respiratory frequency to adapt breathing to physiological demands. We analyzed in mouse neonates, the influence of d-serine upon inspiratory/expiratory durations and the architecture of the inspiratory burst, assessed by pwelch's power spectrum density (PSD) and continuous wavelet transform (CWT) analyses. Suction electrode recordings were performed in slices from the ventral respiratory column (VRC), site of generation of the respiratory rhythm, and in brainstem-spinal cord (en bloc) preparations, from the C5 ventral roots, containing phrenic fibers that in vivo innervate and drive the diaphragm, the main inspiratory muscle. In en bloc and slice preparations, d-serine (100 μM) reduced the expiratory, but not the inspiratory duration, and increased the frequency and the regularity of the respiratory rhythm. In en bloc preparations, d-serine (100 μM) also increased slightly the amplitude of the integrated inspiratory burst and the area under the curve of the integrated inspiratory burst, suggesting a change in the recruitment or the firing pattern of neurons within the burst. Time-frequency analyses revealed that d-serine changed the burst architecture of phrenic roots, widening their frequency spectrum and shifting the position of the core of firing frequencies towards the onset of the inspiratory burst. At the VRC, no clear d-serine induced changes in the frequency-time domain could be established. Our results show that d-serine not only regulates the timing of the respiratory cycle, but also the recruitment strategy of phrenic motoneurons within the inspiratory burst.
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Affiliation(s)
- S Beltrán-Castillo
- Facultad de Química y Biología, Departamento de Biología, Universidad de Santiago de Chile, USACH, PO 9170022, Santiago, Chile; Facultad de Medicina, Departamento de Neurología, Pontificia Universidad Católica de Chile, PO 8330024, Santiago, Chile
| | - M J Olivares
- Facultad de Química y Biología, Departamento de Biología, Universidad de Santiago de Chile, USACH, PO 9170022, Santiago, Chile
| | - M Ochoa
- Facultad de Química y Biología, Departamento de Biología, Universidad de Santiago de Chile, USACH, PO 9170022, Santiago, Chile
| | - J Barria
- Facultad de Química y Biología, Departamento de Biología, Universidad de Santiago de Chile, USACH, PO 9170022, Santiago, Chile; Facultad de Medicina, Universidad Diego Portales, PO 8370007, Santiago, Chile
| | - M Chacón
- Facultad de Ingeniería, Departamento de Ingeniería Informática, Universidad de Santiago de Chile, USACH, PO 9170022 Santiago, Chile
| | - R von Bernhardi
- Facultad de Medicina, Departamento de Neurología, Pontificia Universidad Católica de Chile, PO 8330024, Santiago, Chile.
| | - J Eugenín
- Facultad de Química y Biología, Departamento de Biología, Universidad de Santiago de Chile, USACH, PO 9170022, Santiago, Chile.
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17
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D-Serine, the Shape-Shifting NMDA Receptor Co-agonist. Neurochem Res 2020; 45:1344-1353. [PMID: 32189130 DOI: 10.1007/s11064-020-03014-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/04/2020] [Accepted: 03/11/2020] [Indexed: 12/17/2022]
Abstract
Shape-shifting, a phenomenon wide-spread in folklore, refers to the ability to physically change from one identity to another, typically from an innocuous entity to a destructive one. The amino acid D-serine over the last 25 years has "shape-shifted" into several identities: a purported glial transmitter activating N-methyl-D-aspartate receptors (NMDARs), a co-transmitter concentrated in excitatory glutamatergic neurons, an autocrine that is released at dendritic spines to prime their post-synaptic NMDARs for an instantaneous response to glutamate and an excitotoxic moiety released from inflammatory (A1) astrocytes. This article will review evidence in support of these scenarios and the artifacts that misled investigators of the true identity of D-serine.
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18
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Kumar A. Calcium Signaling During Brain Aging and Its Influence on the Hippocampal Synaptic Plasticity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:985-1012. [PMID: 31646542 DOI: 10.1007/978-3-030-12457-1_39] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Calcium (Ca2+) ions are highly versatile intracellular signaling molecules and are universal second messenger for regulating a variety of cellular and physiological functions including synaptic plasticity. Ca2+ homeostasis in the central nervous system endures subtle dysregulation with advancing age. Research has provided abundant evidence that brain aging is associated with altered neuronal Ca2+ regulation and synaptic plasticity mechanisms. Much of the work has focused on the hippocampus, a brain region critically involved in learning and memory, which is particularly susceptible to dysfunction during aging. The current chapter takes a specific perspective, assessing various Ca2+ sources and the influence of aging on Ca2+ sources and synaptic plasticity in the hippocampus. Integrating the knowledge of the complexity of age-related alterations in neuronal Ca2+ signaling and synaptic plasticity mechanisms will positively shape the development of highly effective therapeutics to treat brain disorders including cognitive impairment associated with aging and neurodegenerative disease.
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Affiliation(s)
- Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
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19
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Mothet JP, Billard JM, Pollegioni L, Coyle JT, Sweedler JV. Investigating brain d-serine: Advocacy for good practices. Acta Physiol (Oxf) 2019; 226:e13257. [PMID: 30650253 PMCID: PMC6462235 DOI: 10.1111/apha.13257] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 12/31/2022]
Abstract
The last two decades have witnessed remarkable advance in our understanding the role of d-amino acids in the mammalian nervous system: from the unknown, to known molecules with unknown functions, to potential central players in health and disease. d-Amino acids have emerged as an important class of signaling molecules. In particular, the exploration of the roles of d-serine in brain physiopathology is a vibrant field that is growing at an accelerating pace. However, disentangling the functions of a chiral molecule in a complex chemical matrice as the brain requires specific measurement and detection methods but is also a challenging task as many molecular tools and models investigators are using can lead to confounded observations. Thus, study of d-amino acids demands accurate methodologies and specific controls, and these have often been lacking. Here we outline best practices for d-amino acid research, with a special emphasis on d-serine. We hope these concepts help move the field to greater rigor and reproducibility, allowing the field to advance.
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Affiliation(s)
- Jean-Pierre Mothet
- Team Gliotransmission & Synaptopathies, Aix Marseille University, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille UMR7286 CNRS, Marseille, France
| | | | - Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell’Insubria, Varese, Italy
| | - Joseph T Coyle
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Jonathan V Sweedler
- Department of Chemistry and the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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20
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Chandran R, Kumar M, Kesavan L, Jacob RS, Gunasekaran S, Lakshmi S, Sadasivan C, Omkumar R. Cellular calcium signaling in the aging brain. J Chem Neuroanat 2019; 95:95-114. [DOI: 10.1016/j.jchemneu.2017.11.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/03/2017] [Accepted: 11/07/2017] [Indexed: 12/21/2022]
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21
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Billard JM. Changes in Serine Racemase-Dependent Modulation of NMDA Receptor: Impact on Physiological and Pathological Brain Aging. Front Mol Biosci 2018; 5:106. [PMID: 30555832 PMCID: PMC6282039 DOI: 10.3389/fmolb.2018.00106] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 11/09/2018] [Indexed: 02/02/2023] Open
Abstract
The N-methyl-D-Aspartate glutamate receptors (NMDARs) are pivotal for the functional and morphological plasticity that are required in neuronal networks for efficient brain activities and notably for cognitive-related abilities. Because NMDARs are heterogeneous in subunit composition and associated with multiple functional regulatory sites, their efficacy is under the tonic influence of numerous allosteric modulations, whose dysfunction generally represents the first step generating pathological states. Among the enzymatic candidates, serine racemase (SR) has recently gathered an increasing interest considering that it tightly regulates the production of d-serine, an amino acid now viewed as the main endogenous co-agonist necessary for NMDAR activation. Nowadays, SR deregulation is associated with a wide range of neurological and psychiatric diseases including schizophrenia, amyotrophic lateral sclerosis, and depression. This review aims at compelling the most recent experimental evidences indicating that changes in SR-related modulation of NMDARs also govern opposite functional dysfunctions in physiological and pathological (Alzheimer's disease) aging that finally results in memory disabilities in both cases. It also highlights SR as a relevant alternative target for new pharmacological strategies aimed at preventing functional alterations and cognitive impairments linked to the aging process.
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22
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Impact of Aging in Microglia-Mediated D-Serine Balance in the CNS. Mediators Inflamm 2018; 2018:7219732. [PMID: 30363571 PMCID: PMC6180939 DOI: 10.1155/2018/7219732] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 08/19/2018] [Accepted: 08/30/2018] [Indexed: 01/12/2023] Open
Abstract
A mild chronic inflammatory state, like that observed in aged individuals, affects microglial function, inducing a dysfunctional phenotype that potentiates neuroinflammation and cytotoxicity instead of neuroprotection in response to additional challenges. Given that inflammatory activation of microglia promotes increased release of D-serine, we postulate that age-dependent inflammatory brain environment leads to microglia-mediated changes on the D-serine-regulated glutamatergic transmission. Furthermore, D-serine dysregulation, in addition to affecting synaptogenesis and synaptic plasticity, appears also to potentiate NMDAR-dependent excitotoxicity, promoting neurodegeneration and cognitive impairment. D-serine dysregulation promoted by microglia could have a role in age-related cognitive impairment and in the induction and progression of neurodegenerative processes like Alzheimer's disease.
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23
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Permpoonputtana K, Tangweerasing P, Mukda S, Boontem P, Nopparat C, Govitrapong P. Long-term administration of melatonin attenuates neuroinflammation in the aged mouse brain. EXCLI JOURNAL 2018; 17:634-646. [PMID: 30108467 PMCID: PMC6088215 DOI: 10.17179/excli2017-654] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 06/11/2018] [Indexed: 01/08/2023]
Abstract
Aging is often accompanied by a decline in cognitive function in conjunction with a variety of neurobiological changes, including neuroinflammation. Melatonin is a key endogenous indoleamine secreted by the pineal gland that plays a crucial role in the regulation of circadian rhythms, is a potent free radical scavenger, has anti-inflammatory activity and serves numerous other functions. However, the role of melatonin in sterile inflammation in the brain has not been fully investigated. In the present study, we investigated the neuroinflammation status in aged mouse brains. The results showed that the protein levels of integrin αM (CD11b), glial fibrillary acidic protein (GFAP), the major pro-inflammatory cytokines (interleukin-1 beta [IL-1β], interleukin-6 [IL-6], and tumor necrosis factor alpha [TNF-α]) and phosphor-nuclear factor kappa B (pNFκB) were significantly increased, while N-methyl-D-aspartate (NMDA) receptor subunits NR2A and NR2B, Ca2+/calmodulin-dependent protein kinase II (CaMKII), and brain-derived neurotrophic factor (BDNF) were down-regulated in the hippocampus and prefrontal cortex (PFC) of 22-months-old (aged) mice compared with 2-months-old (young adult) mice. Melatonin was administered in the drinking water to a cohort of the aged mice at a dose of 10 mg/kg/day, beginning at an age of 16 months for 6 months. Our results revealed that melatonin significantly attenuated the alterations in these protein levels. The present study suggests an advantageous role for melatonin in anti-inflammation, and this may lead to the prevention of memory impairment in aging.
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Affiliation(s)
| | - Patlada Tangweerasing
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Thailand
| | - Sujira Mukda
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Thailand
| | | | - Chutikorn Nopparat
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Thailand
| | - Piyarat Govitrapong
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Thailand.,Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Thailand.,Department of Pharmacology, Faculty of Science, Mahidol University, Thailand
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24
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25
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Beltrán-Castillo S, Olivares MJ, Contreras RA, Zúñiga G, Llona I, von Bernhardi R, Eugenín JL. D-serine released by astrocytes in brainstem regulates breathing response to CO 2 levels. Nat Commun 2017; 8:838. [PMID: 29018191 PMCID: PMC5635109 DOI: 10.1038/s41467-017-00960-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 08/09/2017] [Indexed: 11/17/2022] Open
Abstract
Central chemoreception is essential for adjusting breathing to physiological demands, and for maintaining CO2 and pH homeostasis in the brain. CO2-induced ATP release from brainstem astrocytes stimulates breathing. NMDA receptor (NMDAR) antagonism reduces the CO2-induced hyperventilation by unknown mechanisms. Here we show that astrocytes in the mouse caudal medullary brainstem can synthesize, store, and release d-serine, an agonist for the glycine-binding site of the NMDAR, in response to elevated CO2 levels. We show that systemic and raphe nucleus d-serine administration to awake, unrestrained mice increases the respiratory frequency. Application of d-serine to brainstem slices also increases respiratory frequency, which was prevented by NMDAR blockade. Inhibition of d-serine synthesis, enzymatic degradation of d-serine, or the sodium fluoroacetate-induced impairment of astrocyte functions decrease the basal respiratory frequency and the CO2-induced respiratory response in vivo and in vitro. Our findings suggest that astrocytic release of d-serine may account for the glutamatergic contribution to central chemoreception. Astrocytes are involved in chemoreception in brainstem areas that regulate breathing rhythm, and astrocytes are known to release d-serine. Here the authors show that astrocyte release of d-serine contributes to CO2 sensing and breathing in brainstem slices, and in vivo in awake unrestrained mice.
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Affiliation(s)
- S Beltrán-Castillo
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, 9170022, Chile
| | - M J Olivares
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, 9170022, Chile
| | - R A Contreras
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, 9170022, Chile
| | - G Zúñiga
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, 9170022, Chile
| | - I Llona
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, 9170022, Chile
| | - R von Bernhardi
- Departamento de Neurología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, 8330024, Chile.
| | - J L Eugenín
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, USACH, Santiago, 9170022, Chile.
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26
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Bohmbach K, Schwarz MK, Schoch S, Henneberger C. The structural and functional evidence for vesicular release from astrocytes in situ. Brain Res Bull 2017; 136:65-75. [PMID: 28122264 DOI: 10.1016/j.brainresbull.2017.01.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 01/17/2017] [Accepted: 01/19/2017] [Indexed: 12/31/2022]
Abstract
The concept of the tripartite synapse states that bi-directional signalling between perisynaptic astrocyte processes, presynaptic axonal boutons and postsynaptic neuronal structures defines the properties of synaptic information processing. Ca2+-dependent vesicular release from astrocytes, as one of the mechanisms of astrocyte-neuron communication, has attracted particular attention but has also been the subject of intense debate. In neurons, regulated vesicular release is a strongly coordinated process. It requires a complex release machinery comprised of many individual components ranging from vesicular neurotransmitter transporters and soluble NSF attachment protein receptors (SNARE) proteins to Ca2+-sensors and the proteins that spatially and temporally control exocytosis of synaptic vesicles. If astrocytes employ similar mechanisms to release neurotransmitters is less well understood. The aim of this review is therefore to discuss recent experimental evidence that sheds light on the central structural components responsible for vesicular release from astrocytes in situ.
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Affiliation(s)
- Kirsten Bohmbach
- Institute of Cellular Neurosciences, University of Bonn Medical School, Bonn, Germany.
| | - Martin K Schwarz
- Department of Epileptology, University of Bonn Medical School, Bonn, Germany
| | - Susanne Schoch
- Institute of Neuropathology, University of Bonn Medical School, Bonn, Germany
| | - Christian Henneberger
- Institute of Cellular Neurosciences, University of Bonn Medical School, Bonn, Germany; German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany; Institute of Neurology, University College London, London, United Kingdom.
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Wolosker H, Balu DT, Coyle JT. The Rise and Fall of the d-Serine-Mediated Gliotransmission Hypothesis. Trends Neurosci 2016; 39:712-721. [PMID: 27742076 DOI: 10.1016/j.tins.2016.09.007] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/19/2016] [Accepted: 09/20/2016] [Indexed: 01/26/2023]
Abstract
d-Serine modulates N-methyl d-aspartate receptors (NMDARs) and regulates synaptic plasticity, neurodevelopment, and learning and memory. However, the primary site of d-serine synthesis and release remains controversial, with some arguing that it is a gliotransmitter and others defining it as a neuronal cotransmitter. Results from several laboratories using different strategies now show that the biosynthetic enzyme of d-serine, serine racemase (SR), is expressed almost entirely by neurons, with few astrocytes appearing to contain d-serine. Cell-selective suppression of SR expression demonstrates that neuronal, rather than astrocytic d-serine, modulates synaptic plasticity. Here, we propose an alternative conceptualization whereby astrocytes affect d-serine levels by synthesizing l-serine that shuttles to neurons to fuel the neuronal synthesis of d-serine.
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Affiliation(s)
- Herman Wolosker
- Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 31096, Israel.
| | - Darrick T Balu
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA; Translational Psychiatry Laboratory, McLean Hospital, Belmont, MA 02478, USA.
| | - Joseph T Coyle
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA; Laboratory of Psychiatric and Molecular Neuroscience, McLean Hospital, Belmont, MA 02478, USA.
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Kumar A. NMDA Receptor Function During Senescence: Implication on Cognitive Performance. Front Neurosci 2015; 9:473. [PMID: 26732087 PMCID: PMC4679982 DOI: 10.3389/fnins.2015.00473] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 11/25/2015] [Indexed: 12/13/2022] Open
Abstract
N-methyl-D-aspartate (NMDA) receptors, a family of L-glutamate receptors, play an important role in learning and memory, and are critical for spatial memory. These receptors are tetrameric ion channels composed of a family of related subunits. One of the hallmarks of the aging human population is a decline in cognitive function; studies in the past couple of years have demonstrated deterioration in NMDA receptor subunit expression and function with advancing age. However, a direct relationship between impaired memory function and a decline in NMDA receptors is still ambiguous. Recent studies indicate a link between an age-associated NMDA receptor hypofunction and memory impairment and provide evidence that age-associated enhanced oxidative stress might be contributing to the alterations associated with senescence. However, clear evidence is still deficient in demonstrating the underlying mechanisms and a relationship between age-associated impaired cognitive faculties and NMDA receptor hypofunction. The current review intends to present an overview of the research findings regarding changes in expression of various NMDA receptor subunits and deficits in NMDA receptor function during senescence and its implication in age-associated impaired hippocampal-dependent memory function.
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Affiliation(s)
- Ashok Kumar
- Department of Neuroscience, Evelyn F. and William L. McKnight Brain Institute, University of Florida Gainesville, FL, USA
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Yamamuro K, Kimoto S, Rosen KM, Kishimoto T, Makinodan M. Potential primary roles of glial cells in the mechanisms of psychiatric disorders. Front Cell Neurosci 2015; 9:154. [PMID: 26029044 PMCID: PMC4432872 DOI: 10.3389/fncel.2015.00154] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 04/06/2015] [Indexed: 01/05/2023] Open
Abstract
While neurons have long been considered the major player in multiple brain functions such as perception, emotion, and memory, glial cells have been relegated to a far lesser position, acting as merely a “glue” to support neurons. Multiple lines of recent evidence, however, have revealed that glial cells such as oligodendrocytes, astrocytes, and microglia, substantially impact on neuronal function and activities and are significantly involved in the underlying pathobiology of psychiatric disorders. Indeed, a growing body of evidence indicates that glial cells interact extensively with neurons both chemically (e.g., through neurotransmitters, neurotrophic factors, and cytokines) and physically (e.g., through gap junctions), supporting a role for these cells as likely significant modifiers not only of neural function in brain development but also disease pathobiology. Since questions have lingered as to whether glial dysfunction plays a primary role in the biology of neuropsychiatric disorders or a role related solely to their support of neuronal physiology in these diseases, informative and predictive animal models have been developed over the last decade. In this article, we review recent findings uncovered using glia-specific genetically modified mice with which we can evaluate both the causation of glia dysfunction and its potential role in neuropsychiatric disorders such as autism and schizophrenia.
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Affiliation(s)
- Kazuhiko Yamamuro
- Department of Psychiatry, Faculty of Medicine, Nara Medical University, Kashihara Japan
| | - Sohei Kimoto
- Department of Psychiatry, Faculty of Medicine, Nara Medical University, Kashihara Japan
| | | | - Toshifumi Kishimoto
- Department of Psychiatry, Faculty of Medicine, Nara Medical University, Kashihara Japan
| | - Manabu Makinodan
- Department of Psychiatry, Faculty of Medicine, Nara Medical University, Kashihara Japan
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D'Ascenzo M, Podda MV, Grassi C. The role of D-serine as co-agonist of NMDA receptors in the nucleus accumbens: relevance to cocaine addiction. Front Synaptic Neurosci 2014; 6:16. [PMID: 25076900 PMCID: PMC4100571 DOI: 10.3389/fnsyn.2014.00016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 06/29/2014] [Indexed: 12/20/2022] Open
Abstract
Cocaine addiction is characterized by compulsive drug use despite adverse consequences and high rate of relapse during periods of abstinence. Increasing consensus suggests that addiction to drugs of abuse usurps learning and memory mechanisms normally related to natural rewards, ultimately producing long-lasting neuroadaptations in the mesocorticolimbic system. This system, formed in part by the ventral tegmental area and nucleus accumbens (NAc), has a central role in the development and expression of addictive behaviors. In addition to a broad spectrum of changes that affect morphology and function of NAc excitatory circuits in cocaine–treated animals, impaired N-methyl-D-aspartate receptor (NMDAR)-dependent synaptic plasticity is a typical feature. D-serine, a D-amino acid that has been found at high levels in mammalian brain, binds with high affinity the co-agonist site of NMDAR and mediates, along with glutamate, several important processes including synaptic plasticity. Here we review recent literature focusing on cocaine-induced impairment in synaptic plasticity mechanisms in the NAc and on the fundamental role of D-serine as co-agonist of NMDAR in functional and dysfunctional synaptic plasticity within this nucleus. The emerging picture is that reduced D-serine levels play a crucial role in synaptic plasticity relevant to cocaine addiction. This finding opens new perspectives for therapeutic approaches to treat this addictive state.
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Affiliation(s)
- Marcello D'Ascenzo
- Institute of Human Physiology, Medical School, Universitá Cattolica "S. Cuore" Rome, Italy
| | - Maria Vittoria Podda
- Institute of Human Physiology, Medical School, Universitá Cattolica "S. Cuore" Rome, Italy
| | - Claudio Grassi
- Institute of Human Physiology, Medical School, Universitá Cattolica "S. Cuore" Rome, Italy
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31
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Abstract
D-Serine (DSR) is an endogenous amino acid involved in glia-synapse interactions that has unique neurotransmitter characteristics. DSR acts as obligatory coagonist at the glycine site associated with the N-methyl-D-aspartate subtype of glutamate receptors (NMDAR) and has a cardinal modulatory role in major NMDAR-dependent processes including NMDAR-mediated neurotransmission, neurotoxicity, synaptic plasticity, and cell migration. Since either over- or underfunction of NMDARs may be involved in the pathophysiology of neuropsychiatric disorders; the pharmacological manipulation of DSR signaling represents a major drug development target. A first generation of proof-of-concept animal and clinical studies suggest beneficial DSR effects in treatment-refractory schizophrenia, movement, depression, and anxiety disorders and for the improvement of cognitive performance. A related developing pharmacological strategy is the indirect modification of DSR synaptic levels by use of compounds that alter the function of main enzymes responsible for DSR production and degradation. Accumulating data indicate that, during the next decade, we will witness important advances in the understanding of DSR role that will further contribute to elucidating the causes of neuropsychiatric disorders and will be instrumental in the development of innovative treatments.
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Martineau M, Parpura V, Mothet JP. Cell-type specific mechanisms of D-serine uptake and release in the brain. Front Synaptic Neurosci 2014; 6:12. [PMID: 24910611 PMCID: PMC4039169 DOI: 10.3389/fnsyn.2014.00012] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 05/02/2014] [Indexed: 12/30/2022] Open
Abstract
Accumulating evidence during the last decade established that D-serine is a key signaling molecule utilized by neurons and astroglia in the mammalian central nervous system. D-serine is increasingly appreciated as the main physiological endogenous coagonist for synaptic NMDA receptors at central excitatory synapses; it is mandatory for long-term changes in synaptic strength, memory, learning, and social interactions. Alterations in the extracellular levels of D-serine leading to disrupted cell-cell signaling are a trademark of many chronic or acute neurological (i.e., Alzheimer disease, epilepsy, stroke) and psychiatric (i.e., schizophrenia) disorders, and are associated with addictive behavior (i.e., cocaine addiction). Indeed, fine tuning of the extracellular levels of D-serine, achieved by various molecular machineries and signaling pathways, is necessary for maintenance of accurate NMDA receptor functions. Here, we review the experimental data supporting the notion that astroglia and neurons use different pathways to regulate levels of extracellular D-serine.
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Affiliation(s)
- Magalie Martineau
- Department of Cellular Biophysics, Institute for Medical Physics and Biophysics, University of Muenster Muenster, Germany
| | - Vladimir Parpura
- Department of Neurobiology, University of Alabama at Birmingham Birmingham, AL, USA ; Department of Biotechnology, University of Rijeka Rijeka, Croatia
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Chen XG, Wang YH, Wen CC, Chen YH. Overdose of D-serine Induces Movement Disorder and Neuromuscular Changes of Zebrafish Larvae. J Toxicol Pathol 2014; 27:19-24. [PMID: 24791063 PMCID: PMC4000069 DOI: 10.1293/tox.2013-0032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 09/04/2013] [Indexed: 01/28/2023] Open
Abstract
D-serine is a well-known activator of N-methyl-D-aspartate receptors; however, little is known about the teratogenic effects of D-serine overdose during early embryonic development. Here, we used zebrafish as a model to test toxicity and teratogenicity, since they have transparent eggs, making the organogenesis of zebrafish embryos easier to be observed. After D-serine injection (100–1000 ppm), the most evident defective phenotypes were bent trunk phenotypes, including malformed somite boundary, twisted body axis and shorter body length. As the injection dosages increased, the rates of embryos with bent trunk phenotypes decreased (0% for 0 ppm, n=573; 59.9~84.3% for 100–1000 ppm of D-serine, n=383–451). In addition, D-serine-injected embryos exhibited significantly reduced the frequencies of spontaneous in-chorion contraction (21.7 for 0 ppm vs. 18.3–0.9 for 100–1000 ppm D-serine, n=30) in comparison with mock-treated controls (0 ppm). Subtle changes are easily observed by staining with specific monoclonal antibodies F59, Znp1, Zn5 and α-bungarotoxin to detect morphological changes in muscle fibers, primary motor axons, secondary motor axon projections and neuromuscular junctions, respectively. Our data show that overdose of D-serine leads to misalignment of muscle fibers and motor neuron defects, especially secondary motor neuron axonal growth defects.
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Affiliation(s)
- Xing-Guang Chen
- Department of Chemistry, Tamkang University, No. 151 Ying-chuan Road, Tamsui, New Taipei City 251, Taiwan
| | - Yun-Hsin Wang
- Division of Basic Research, Koo Foundation Sun Yat-Sen Cancer Center, No. 125, Lide Road, Beitou, Taipei, Taiwan
| | - Chi-Chung Wen
- Department of Mathematics, Tamkang University, No. 151, Ying-chuan Road, Tamsui, New Taipei City, Taiwan
| | - Yau-Hung Chen
- Department of Chemistry, Tamkang University, No. 151 Ying-chuan Road, Tamsui, New Taipei City 251, Taiwan
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Astroglial d-serine is the endogenous co-agonist at the presynaptic NMDA receptor in rat entorhinal cortex. Neuropharmacology 2014; 83:118-27. [PMID: 24747728 DOI: 10.1016/j.neuropharm.2014.04.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 03/17/2014] [Accepted: 04/07/2014] [Indexed: 12/17/2022]
Abstract
Presynaptic NMDA receptors facilitate the release of glutamate at excitatory cortical synapses and are involved in regulation of synaptic dynamics and plasticity. At synapses in the entorhinal cortex these receptors are tonically activated and provide a positive feedback modulation of the level of background excitation. NMDA receptor activation requires obligatory occupation of a co-agonist binding site, and in the present investigation we have examined whether this site on the presynaptic receptor is activated by endogenous glycine or d-serine. We used whole-cell patch clamp recordings of spontaneous AMPA receptor-mediated synaptic currents from rat entorhinal cortex neurones in vitro as a monitor of presynaptic glutamate release. Addition of exogenous glycine or d-serine had minimal effects on spontaneous release, suggesting that the co-agonist site was endogenously activated and likely to be saturated in our slices. This was supported by the observation that a co-agonist site antagonist reduced the frequency of spontaneous currents. Depletion of endogenous glycine by enzymatic breakdown with a bacterial glycine oxidase had little effect on glutamate release, whereas d-serine depletion with a yeast d-amino acid oxidase significantly reduced glutamate release, suggesting that d-serine is the endogenous agonist. Finally, the effects of d-serine depletion were mimicked by compromising astroglial cell function, and this was rescued by exogenous d-serine, indicating that astroglial cells are the provider of the d-serine that tonically activates the presynaptic NMDA receptor. We discuss the significance of these observations for the aetiology of epilepsy and possible targeting of the presynaptic NMDA receptor in anticonvulsant therapy.
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35
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Paul P, de Belleroche J. The role of D-serine and glycine as co-agonists of NMDA receptors in motor neuron degeneration and amyotrophic lateral sclerosis (ALS). Front Synaptic Neurosci 2014; 6:10. [PMID: 24795623 PMCID: PMC3997022 DOI: 10.3389/fnsyn.2014.00010] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 03/29/2014] [Indexed: 12/11/2022] Open
Abstract
The fundamental role of D-serine as a co-agonist at the N-methyl-D-aspartate receptor (NMDAR), mediating both physiological actions of glutamate in long term potentiation and nociception and also pathological effects mediated by excitotoxicty, are well-established. More recently, a direct link to a chronic neurodegenerative disease, amyotrophic lateral sclerosis/motor neuron disease (ALS) has been suggested by findings that D-serine levels are elevated in sporadic ALS and the G93A SOD1 model of ALS (Sasabe et al., 2007, 2012) and that a pathogenic mutation (R199W) in the enzyme that degrades D-serine, D-amino acid oxidase (DAO), co-segregates with disease in familial ALS (Mitchell et al., 2010). Moreover, D-serine, its biosynthetic enzyme, serine racemase (SR) and DAO are abundant in human spinal cord and severely depleted in ALS. Using cell culture models, we have defined the effects of R199W-DAO, and shown that it activates autophagy, leads to the formation of ubiquitinated aggregates and promotes apoptosis, all of which processes are attenuated by a D-serine/glycine site NMDAR antagonist. These studies provide considerable insight into the crosstalk between neurons and glia and also into potential therapeutic approaches for ALS.
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Affiliation(s)
- Praveen Paul
- Neurogenetics Group, Division of Brain Sciences, Department of Medicine, Imperial College London London, UK
| | - Jackie de Belleroche
- Neurogenetics Group, Division of Brain Sciences, Department of Medicine, Imperial College London London, UK
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36
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Pathogenic effects of amyotrophic lateral sclerosis-linked mutation in D-amino acid oxidase are mediated by D-serine. Neurobiol Aging 2014; 35:876-85. [DOI: 10.1016/j.neurobiolaging.2013.09.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 08/15/2013] [Accepted: 09/06/2013] [Indexed: 01/05/2023]
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Cappelletti P, Campomenosi P, Pollegioni L, Sacchi S. The degradation (by distinct pathways) of humand-amino acid oxidase and its interacting partner pLG72 - two key proteins ind-serine catabolism in the brain. FEBS J 2013; 281:708-23. [DOI: 10.1111/febs.12616] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 11/08/2013] [Accepted: 11/11/2013] [Indexed: 12/26/2022]
Affiliation(s)
- Pamela Cappelletti
- Dipartimento di Biotecnologie e Scienze della Vita; Università degli Studi dell'Insubria; Varese Italy
- Centro Interuniversitario di Ricerca in Biotecnologie Proteiche ‘The Protein Factory’; Politecnico di Milano; ICRM-CNR Milano and Università degli studi dell'Insubria; Varese Italy
| | - Paola Campomenosi
- Dipartimento di Biotecnologie e Scienze della Vita; Università degli Studi dell'Insubria; Varese Italy
- Centro Interuniversitario di Ricerca in Biotecnologie Proteiche ‘The Protein Factory’; Politecnico di Milano; ICRM-CNR Milano and Università degli studi dell'Insubria; Varese Italy
| | - Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita; Università degli Studi dell'Insubria; Varese Italy
- Centro Interuniversitario di Ricerca in Biotecnologie Proteiche ‘The Protein Factory’; Politecnico di Milano; ICRM-CNR Milano and Università degli studi dell'Insubria; Varese Italy
| | - Silvia Sacchi
- Dipartimento di Biotecnologie e Scienze della Vita; Università degli Studi dell'Insubria; Varese Italy
- Centro Interuniversitario di Ricerca in Biotecnologie Proteiche ‘The Protein Factory’; Politecnico di Milano; ICRM-CNR Milano and Università degli studi dell'Insubria; Varese Italy
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Ribeiro BMM, do Carmo MRS, Freire RS, Rocha NFM, Borella VCM, de Menezes AT, Monte AS, Gomes PXL, de Sousa FCF, Vale ML, de Lucena DF, Gama CS, Macêdo D. Evidences for a progressive microglial activation and increase in iNOS expression in rats submitted to a neurodevelopmental model of schizophrenia: reversal by clozapine. Schizophr Res 2013; 151:12-9. [PMID: 24257517 DOI: 10.1016/j.schres.2013.10.040] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/17/2013] [Accepted: 10/28/2013] [Indexed: 01/11/2023]
Abstract
Schizophrenia was proposed as a progressive neurodevelopmental disorder. In this regard herein we attempted to determine progressive inflammatory and oxidative alterations induced by a neonatal immune challenge and its possible reversal by clozapine administration. For this end, Wistar rats at postnatal day (PN) 5-7 were administered the viral mimetic polyriboinosinic-polyribocytidilic acid (polyI:C) or saline. A distinct group of animals additionally received the antipsychotic drug clozapine (25mg/kg) from PN60 to 74. At PN35 (periadolescence), 60 (adult) and 74 (adulthood) the animals were submitted to behavioral determinations of prepulse inhibition of the startle (PPI) and Y maze task for working memory evaluation. At PN35 and 74 the animals were sacrificed and the hippocampus (HC), prefrontal cortex (PFC) and striatum (ST) immunostained for Iba-1, a microglial marker, and inducible nitric oxide synthase (iNOS). At PN74 oxidative stress parameters, such as, reduced glutathione levels (GSH) and lipid peroxidation were determined. The results showed a progressive increase of microglial activation and iNOS immunostaining from PN35 to PN74 mainly in the CA2 and CA3 regions of the HC and in the ST. At PN74 neonatal challenge also induced an oxidative imbalance. These inflammatory alterations were accompanied by deficits in PPI and working memory only in adult life that were reversed by clozapine. Clozapine administration reversed microglial activation and iNOS increase, but not the alterations of oxidative stress parameters. Taken together these results give further evidences for a neuroprogressive etiology and course of schizophrenia and that clozapine may partly alleviate this process.
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Affiliation(s)
- Bruna Mara Machado Ribeiro
- Neuropharmacology Laboratory, Department of Physiology and Pharmacology, Universidade Federal do Ceará, Fortaleza, CE, Brazil
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39
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The serine shuttle between glia and neurons: implications for neurotransmission and neurodegeneration. Biochem Soc Trans 2013; 41:1546-50. [DOI: 10.1042/bst20130220] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
D-Serine is a physiological co-agonist of NMDARs (N-methyl-D-aspartate receptors) required for neurotransmission, synaptic plasticity and neurotoxicity. There is no consensus, however, on the relative roles of neurons and astrocytes in D-serine signalling. The effects of D-serine had been attributed to its role as a gliotransmitter specifically produced and released by astrocytes. In contrast, recent studies indicate that neurons regulate their own NMDARs by releasing D-serine via plasma membrane transporters and depolarization-sensitive pathways. Only a minority of astrocytes contain authentic D-serine, whereas neuronal D-serine accounts for up to 90% of the total D-serine pool. Neuronal and glial D-serine production requires astrocytic L-serine generated by a 3-phosphoglycerate dehydrogenase-dependent pathway. These findings support a model whereby astrocyte-derived L-serine shuttles to neurons to fuel the synthesis of D-serine by serine racemase. We incorporate these new findings in a revised model of serine dynamics, called the glia–neuron serine shuttle, which highlights the role of glia–neuron cross-talk for optimal NMDAR activity and brain development.
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40
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Abstract
d-Serine is an endogenous ligand for NMDARs generated from l-serine by the enzyme serine racemase (Srr). Both neuronal and glial localizations have been reported for d-serine and Srr. 3-Phosphoglycerate dehydrogenase is an exclusively astrocytic enzyme that catalyzes the first committed step of l-serine biosynthesis. Using transgenic mice expressing enhanced green fluorescent protein under the Srr promoter and mice with targeted deletion of Srr or 3-Phosphoglycerate dehydrogenase, we demonstrate predominantly neuronal sources of d-serine dependent on astrocytic supply of l-serine. These findings clarify the cellular basis for the regulation of NMDAR neurotransmission by d-serine.
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Scianni M, Antonilli L, Chece G, Cristalli G, Di Castro MA, Limatola C, Maggi L. Fractalkine (CX3CL1) enhances hippocampal N-methyl-D-aspartate receptor (NMDAR) function via D-serine and adenosine receptor type A2 (A2AR) activity. J Neuroinflammation 2013; 10:108. [PMID: 23981568 PMCID: PMC3765929 DOI: 10.1186/1742-2094-10-108] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 05/28/2013] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND N-Methyl-D-aspartate receptors (NMDARs) play fundamental roles in basic brain functions such as excitatory neurotransmission and learning and memory processes. Their function is largely regulated by factors released by glial cells, including the coagonist d-serine. We investigated whether the activation of microglial CX3CR1 induces the release of factors that modulate NMDAR functions. METHODS We recorded the NMDAR component of the field excitatory postsynaptic potentials (NMDA-fEPSPs) elicited in the CA1 stratum radiatum of mouse hippocampal slices by Shaffer collateral stimulation and evaluated D-serine content in the extracellular medium of glial primary cultures by mass spectrometry analysis. RESULTS We demonstrated that CX3CL1 increases NMDA-fEPSPs by a mechanism involving the activity of the adenosine receptor type A2 (A2AR) and the release of the NMDAR coagonist D-serine. Specifically (1) the selective A2AR blocker 7-(2-phenylethyl)-5-amino-2-(2-furyl)-pyrazolo-[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine (SCH58261) and the genetic ablation of A2AR prevent CX3CL1 action while the A2AR agonist 5-(6-amino-2-(phenethylthio)-9H-purin-9-yl)-N-ethyl-3,4-dihydroxytetrahydrofuran-2-carboxamide (VT7) mimics CX3CL1 effect, and (2) the selective blocking of the NMDAR glycine (and D-serine) site by 5,7-dicholorokynurenic acid (DCKA), the enzymatic degradation of D-serine by D-amino acid oxidase (DAAO) and the saturation of the coagonist site by D-serine, all block the CX3CL1 effect. In addition, mass spectrometry analysis demonstrates that stimulation of microglia and astrocytes with CX3CL1 or VT7 increases D-serine release in the extracellular medium. CONCLUSIONS CX3CL1 transiently potentiates NMDAR function though mechanisms involving A2AR activity and the release of D-serine.
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Affiliation(s)
- Maria Scianni
- Institute Pasteur-Cenci Bolognetti Foundation, Department of Physiology and Pharmacology, University Sapienza, Rome, Italy.
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42
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Billard JM. Serine racemase as a prime target for age-related memory deficits. Eur J Neurosci 2013; 37:1931-8. [DOI: 10.1111/ejn.12226] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 02/26/2013] [Accepted: 03/22/2013] [Indexed: 11/29/2022]
Affiliation(s)
- J.-M. Billard
- Centre de Psychiatrie et Neurosciences; Faculté de Médecine; Université Paris Descartes; UMR 894; Sorbonne Paris Cité; 2 ter rue d'Alésia; Paris; 75014; France
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Paula-Lima AC, Brito-Moreira J, Ferreira ST. Deregulation of excitatory neurotransmission underlying synapse failure in Alzheimer's disease. J Neurochem 2013; 126:191-202. [PMID: 23668663 DOI: 10.1111/jnc.12304] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 05/09/2013] [Accepted: 05/10/2013] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia in the elderly. Memory loss in AD is increasingly attributed to soluble oligomers of the amyloid-β peptide (AβOs), toxins that accumulate in AD brains and target particular synapses. Glutamate receptors appear to be centrally involved in synaptic targeting by AβOs. Once bound to neurons, AβOs dysregulate the activity and reduce the surface expression of both N-methyl-D-aspartate (NMDA) and 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propanoic acid (AMPA) types of glutamate receptors, impairing signaling pathways involved in synaptic plasticity. In the extracellular milieu, AβOs promote accumulation of the excitatory amino acids, glutamate and D-serine. This leads to overactivation of glutamate receptors, triggering abnormal calcium signals with noxious impacts on neurons. Here, we review key findings linking AβOs to deregulated glutamate neurotransmission and implicating this as a primary mechanism of synapse failure in AD. We also discuss strategies to counteract the impact of AβOs on excitatory neurotransmission. In particular, we review evidence showing that inducing neuronal hyperpolarization via activation of inhibitory GABA(A) receptors prevents AβO-induced excitotoxicity, suggesting that this could comprise a possible therapeutic approach in AD.
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Affiliation(s)
- Andrea C Paula-Lima
- Department of Basic Sciences, Faculty of Dentistry, University of Chile, Santiago, Chile.
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Maucler C, Pernot P, Vasylieva N, Pollegioni L, Marinesco S. In vivo D-serine hetero-exchange through alanine-serine-cysteine (ASC) transporters detected by microelectrode biosensors. ACS Chem Neurosci 2013; 4:772-81. [PMID: 23581544 DOI: 10.1021/cn4000549] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
D-serine, a co-agonist of N-methyl D-aspartate (NMDA) receptors, has been implicated in neurological and psychiatric disorders such as cerebral ischemia, lateral amyotrophic sclerosis, or schizophrenia. D-serine signaling represents an important pharmacological target for treating these diseases; however, the biochemical mechanisms controlling extracellular D-serine levels in vivo are still unclear. D-serine heteroexchange through small neutral amino acid transporters has been shown in cell cultures and brain slices and could provide a biochemical mechanism for the control of D-serine extracellular concentration in vivo. Alternatively, exocytotic D-serine release has also been proposed. In this study, the dynamics of D-serine release and clearance were explored in vivo on a second-by-second time scale using microelectrode biosensors. The rate of D-serine clearance in the rat frontal cortex after a microionophoretic injection revealed a transporter-mediated uptake mechanism. D-serine uptake was blocked by small neutral l-amino acids, implicating alanine-serine-cysteine (ASC) transporters, in particular high affinity Asc-1 and low affinity ASCT2 transporters. Interestingly, changes in alanine, serine, or threonine levels resulted in D-serine release through ASC transporters. Asc-1, but not ASCT2, appeared to release D-serine in response to changes in amino acid concentrations. Finally, neuronal silencing by tetrodotoxin increased D-serine extracellular concentration by an ASC-transporter-dependent mechanism. Together, these results indicate that D-serine heteroexchange through ASC transporters is present in vivo and may constitute a key component in the regulation of D-serine extracellular concentration.
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Affiliation(s)
- Caroline Maucler
- INSERM U1028; CNRS UMR5292 Lyon Neuroscience Research Center, AniRA-Neurochem technological platform, team WAKING, Lyon F-69000, France
- Université Claude Bernard Lyon 1, Lyon F-69000, France
| | - Pierre Pernot
- INSERM U1028; CNRS UMR5292 Lyon Neuroscience Research Center, AniRA-Neurochem technological platform, team WAKING, Lyon F-69000, France
- Université Claude Bernard Lyon 1, Lyon F-69000, France
| | - Natalia Vasylieva
- INSERM U1028; CNRS UMR5292 Lyon Neuroscience Research Center, AniRA-Neurochem technological platform, team WAKING, Lyon F-69000, France
- Université Claude Bernard Lyon 1, Lyon F-69000, France
- Institut de nanotechnologie de Lyon, CNRS UMR-5270, INSA de Lyon, France
| | - Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell’Insubria, Varese, Italy
- “The Protein Factory”, Centro Interuniversitario di Ricerca in Biotecnologie Proteiche ICRM-CNR Milano, Politecnico di Milano and Università degli studi dell’Insubria, Italy
| | - Stéphane Marinesco
- INSERM U1028; CNRS UMR5292 Lyon Neuroscience Research Center, AniRA-Neurochem technological platform, team WAKING, Lyon F-69000, France
- Université Claude Bernard Lyon 1, Lyon F-69000, France
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Ma T, Abazyan S, Abazyan B, Nomura J, Yang C, Seshadri S, Sawa A, Snyder S, Pletnikov M. Pathogenic disruption of DISC1-serine racemase binding elicits schizophrenia-like behavior via D-serine depletion. Mol Psychiatry 2013; 18:557-67. [PMID: 22801410 PMCID: PMC3475769 DOI: 10.1038/mp.2012.97] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Perturbation of Disrupted-In-Schizophrenia-1 (DISC1) and D-serine/NMDA receptor hypofunction have both been implicated in the pathophysiology of schizophrenia and other psychiatric disorders. In the present study, we demonstrate that these two pathways intersect with behavioral consequences. DISC1 binds to and stabilizes serine racemase (SR), the enzyme that generates D-serine, an endogenous co-agonist of the NMDA receptor. Mutant DISC1 fails to bind to SR, facilitating ubiquitination and degradation of SR and a decrease in D-serine production. To elucidate DISC1-SR interactions in vivo, we generated a mouse model of selective and inducible expression of mutant DISC1 in astrocytes, the main source of D-serine in the brain. Expression of mutant DISC1 downregulates endogenous DISC1 and decreases protein but not mRNA levels of SR, resulting in diminished production of D-serine. In contrast, mutant DISC1 does not alter levels of ALDH1L1, connexins, GLT-1 or binding partners of DISC1 and SR, LIS1 or PICK1. Adult male and female mice with lifelong expression of mutant DISC1 exhibit behavioral abnormalities consistent with hypofunction of NMDA neurotransmission. Specifically, mutant mice display greater responses to an NMDA antagonist, MK-801, in open field and pre-pulse inhibition of the acoustic startle tests and are significantly more sensitive to the ameliorative effects of D-serine. These findings support a model wherein mutant DISC1 leads to SR degradation via dominant negative effects, resulting in D-serine deficiency that diminishes NMDA neurotransmission thus linking DISC1 and NMDA pathophysiological mechanisms in mental illness.
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Affiliation(s)
- T.M. Ma
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD
| | - S. Abazyan
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - B. Abazyan
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - J. Nomura
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD,Division of Molecular Medical Science, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan
| | - C. Yang
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - S. Seshadri
- Division of Molecular Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - A. Sawa
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD,Division of Molecular Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - S.H. Snyder
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD,Departments of Pharmacology and Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD,co-corresponding authors
| | - M.V. Pletnikov
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD,The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD,Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD,co-corresponding authors
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Storage and uptake of D-serine into astrocytic synaptic-like vesicles specify gliotransmission. J Neurosci 2013; 33:3413-23. [PMID: 23426669 DOI: 10.1523/jneurosci.3497-12.2013] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Glial cells are increasingly recognized as active players that profoundly influence neuronal synaptic transmission by specialized signaling pathways. In particular, astrocytes have been shown recently to release small molecules, such as the amino acids l-glutamate and d-serine as "gliotransmitters," which directly control the efficacy of adjacent synapses. However, it is still controversial whether gliotransmitters are released from a cytosolic pool or by Ca(2+)-dependent exocytosis from secretory vesicles, i.e., by a mechanism similar to the release of synaptic vesicles in synapses. Here we report that rat cortical astrocytes contain storage vesicles that display morphological and biochemical features similar to neuronal synaptic vesicles. These vesicles share some, but not all, membrane proteins with synaptic vesicles, including the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) synaptobrevin 2, and contain both l-glutamate and d-serine. Furthermore, they show uptake of l-glutamate and d-serine that is driven by a proton electrochemical gradient. d-Serine uptake is associated with vesicle acidification and is dependent on chloride. Whereas l-serine is not transported, serine racemase, the synthesizing enzyme for d-serine, is anchored to the membrane of the vesicles, allowing local generation of d-serine. Finally, we reveal a previously unexpected mutual vesicular synergy between d-serine and l-glutamate filling in glia vesicles. We conclude that astrocytes contain vesicles capable of storing and releasing d-serine, l-glutamate, and most likely other neuromodulators in an activity-dependent manner.
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Kang N, Peng H, Yu Y, Stanton PK, Guilarte TR, Kang J. Astrocytes release D-serine by a large vesicle. Neuroscience 2013; 240:243-57. [PMID: 23485803 DOI: 10.1016/j.neuroscience.2013.02.029] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 01/14/2013] [Accepted: 02/13/2013] [Indexed: 11/30/2022]
Abstract
Long-term potentiation (LTP) of synaptic transmission in the CA1 region of the hippocampus depends on the activation of N-methyl-D-aspartate receptors (NMDARs), which can be regulated by Ca²⁺-dependent release of D-serine from astrocytes. The detailed mechanism underlying astrocytic d-serine release is still unknown. In hippocampal slices prepared from Sprague-Dawley rats, we found that clamping astrocytic [Ca²⁺] at 100-150 nM or puffing artificial cerebrospinal fluid (ACSF) into the extracellular space (weak mechanical stimulation) enhanced the synaptic activation of NMDARs. The enhancement was blocked by the NMDAR glycine site antagonist 5,7-dichlorokynurenic acid, glycine saturation, and infusion of astrocytes with D-amino acid oxidase and the serine racemase inhibitor L-erythro-3-hydroxyaspartate, suggesting the involvement of astrocytic D-serine release. Intracellular 100-150 nM [Ca²⁺] or puffing ACSF stimulated astrocytes to generate D-serine-containing large vesicles (1-3 μm), exocytotic fusion of which released D-serine. The formation of astrocytic large vesicles involved the intracellular fusion of small vesicles and/or other organelles. Spontaneous fusion of large vesicles occurred occasionally in astrocytes at rest, contributing to baseline D-serine levels, which increased the rising slope of NMDAR post-burst potentiation (PBP) without altering the PBP peak amplitude. Thus, under physiological conditions, astrocytic D-serine release by large vesicles facilitated weak theta-burst (TBS consisting of five bursts), but not strong TBS (TBS consisting of 10 bursts) stimulation-induced LTP.
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Affiliation(s)
- N Kang
- Department of Cell Biology and Anatomy, New York Medical College, Basic Science Building, Room 220, Valhalla, NY 10595, USA
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Filali M, Lalonde R. The effects of subchronic d-serine on left–right discrimination learning, social interaction, and exploratory activity in APPswe/PS1 mice. Eur J Pharmacol 2013; 701:152-8. [DOI: 10.1016/j.ejphar.2012.12.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 12/12/2012] [Accepted: 12/19/2012] [Indexed: 10/27/2022]
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López-Hidalgo M, Salgado-Puga K, Alvarado-Martínez R, Medina AC, Prado-Alcalá RA, García-Colunga J. Nicotine uses neuron-glia communication to enhance hippocampal synaptic transmission and long-term memory. PLoS One 2012; 7:e49998. [PMID: 23185511 PMCID: PMC3503711 DOI: 10.1371/journal.pone.0049998] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 10/19/2012] [Indexed: 01/08/2023] Open
Abstract
Nicotine enhances synaptic transmission and facilitates long-term memory. Now it is known that bi-directional glia-neuron interactions play important roles in the physiology of the brain. However, the involvement of glial cells in the effects of nicotine has not been considered until now. In particular, the gliotransmitter D-serine, an endogenous co-agonist of NMDA receptors, enables different types of synaptic plasticity and memory in the hippocampus. Here, we report that hippocampal long-term synaptic plasticity induced by nicotine was annulled by an enzyme that degrades endogenous D-serine, or by an NMDA receptor antagonist that acts at the D-serine binding site. Accordingly, both effects of nicotine: the enhancement of synaptic transmission and facilitation of long-term memory were eliminated by impairing glial cells with fluoroacetate, and were restored with exogenous D-serine. Together, these results show that glial D-serine is essential for the long-term effects of nicotine on synaptic plasticity and memory, and they highlight the roles of glial cells as key participants in brain functions.
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Affiliation(s)
- Mónica López-Hidalgo
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro, México
| | - Karla Salgado-Puga
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro, México
| | - Reynaldo Alvarado-Martínez
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro, México
| | - Andrea Cristina Medina
- Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro, México
| | - Roberto A. Prado-Alcalá
- Departamento de Neurobiología Conductual y Cognitiva, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro, México
| | - Jesús García-Colunga
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro, México
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D-Serine Production, Degradation, and Transport in ALS: Critical Role of Methodology. Neurol Res Int 2012; 2012:625245. [PMID: 23029613 PMCID: PMC3458282 DOI: 10.1155/2012/625245] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Accepted: 07/31/2012] [Indexed: 01/12/2023] Open
Abstract
In mammalian systems, D-serine is perhaps the most biologically active D-amino acid described to date. D-serine is a coagonist at the NMDA-receptor, and receptor activation is dependent on D-serine binding. Because D-serine binding dramatically increases receptor affinity for glutamate, it can produce excitotoxicity without any change in glutamate per se. D-serine is twofold higher in the spinal cords of mSOD1 (G93A) ALS mice, and the deletion of serine racemase (SR), the enzyme that produces D-serine, results in an earlier onset of symptoms, but with a much slower rate of disease progression. Localization studies within the brain suggest that mSOD1 and subsequent glial activation could contribute to the alterations in SR and D-serine seen in ALS. By also degrading both D-serine and L-serine, SR appears to be a prime bidirectional regulator of free serine levels in vivo. Therefore, accurate and reproducible measurements of D-serine are critical to understanding its regulation by SR. Several methods for measuring D-serine have been employed, and significant issues related to validation and standardization remain unresolved. Further insights into the intracellular transport and tissue-specific compartmentalization of D-serine within the CNS will aid in the understanding of the role of D-serine in the pathogenesis of ALS.
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