1
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Han S, Kim J, Kim SH, Youn W, Kim J, Ji GY, Yang S, Park J, Lee GM, Kim Y, Choi IS. In vitro induction of in vivo-relevant stellate astrocytes in 3D brain-derived, decellularized extracellular matrices. Acta Biomater 2023; 172:218-233. [PMID: 37788738 DOI: 10.1016/j.actbio.2023.09.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 09/25/2023] [Accepted: 09/26/2023] [Indexed: 10/05/2023]
Abstract
In vitro fabrication of 3D cell culture systems that could provide in vivo tissue-like, structural, and biochemical environments to neural cells is essential not only for fundamental studies on brain function and behavior, but also for tissue engineering and regenerative medicine applicable to neural injury and neurodegenerative diseases. In particular, for astrocytes-which actively respond to the surroundings and exhibit varied morphologies based on stimuli (e.g., stiffness and chemicals) in vitro, as well as physiological or pathological conditions in vivo-it is crucial to establish an appropriate milieu in in vitro culture platforms. Herein, we report the induction of in vivo-relevant, stellate-shaped astrocytes derived from cortices of Rattus norvegicus by constructing the 3D cell culture systems of brain-derived, decellularized extracellular matrices (bdECMs). The bdECM hydrogels were mechanically stable and soft, and the bdECM-based 3D scaffolds supplied biochemically active environments that astrocytes could interact with, leading to the development of in vivo-like stellate structures. In addition to the distinct morphology with actively elongated endfeet, the astrocytes, cultured in 3D bdECM scaffolds, would have neurosupportive characteristics, indicated by the accelerated neurite outgrowth in the astrocyte-conditioned media. Furthermore, next-generation sequencing showed that the gene expression profiles of astrocytes cultured in bdECMs were significantly different from those cultured on 2D surfaces. The stellate-shaped astrocytes in the bdECMs were analyzed to have reached a more mature state, for instance, with decreased expression of genes for scaffold ECMs, actin filaments, and cell division. The results suggest that the bdECM-based 3D culture system offers an advanced platform for culturing primary cortical astrocytes and their mixtures with other neural cells, providing a brain-like, structural and biochemical milieu that promotes the maturity and in vivo-like characteristics of astrocytes in both form and gene expression. STATEMENT OF SIGNIFICANCE: Decellularized extracellular matrices (dECMs) have emerged as strong candidates for the construction of three-dimensional (3D) cell cultures in vitro, owing to the potential to provide native biochemical and physical environments. In this study, we fabricated hydrogels of brain-derived dECMs (bdECMs) and cultured primary astrocytes within the bdECM hydrogels in a 3D context. The cultured astrocytes exhibited a stellate morphology distinct from conventional 2D cultures, featuring tridimensionally elongated endfeet. qRT-PCR and NGS-based transcriptomic analyses revealed gene expression patterns indicative of a more mature state, compared with the 2D culture. Moreover, astrocytes cultured in bdECMs showed neurosupportive characteristics, as demonstrated by the accelerated neurite outgrowth in astrocyte-conditioned media. We believe that the bdECM hydrogel-based culture system can serve as an in vitro model system for astrocytes and their coculture with other neural cells, holding significant potential for neural engineering and therapeutic applications.
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Affiliation(s)
- Sol Han
- Center for Cell-Encapsulation Research, Department of Chemistry, KAIST, Daejeon 34141, South Korea
| | - Jungnam Kim
- Center for Cell-Encapsulation Research, Department of Chemistry, KAIST, Daejeon 34141, South Korea
| | - Su Hyun Kim
- Department of Biological Sciences, KAIST, Daejeon 34141, South Korea
| | - Wongu Youn
- Center for Cell-Encapsulation Research, Department of Chemistry, KAIST, Daejeon 34141, South Korea
| | - Jihoo Kim
- Center for Cell-Encapsulation Research, Department of Chemistry, KAIST, Daejeon 34141, South Korea
| | - Gil Yong Ji
- Cannabis Medical, Inc., Asan 31418, South Korea
| | - Seoin Yang
- Center for Cell-Encapsulation Research, Department of Chemistry, KAIST, Daejeon 34141, South Korea
| | - Joohyouck Park
- Center for Cell-Encapsulation Research, Department of Chemistry, KAIST, Daejeon 34141, South Korea
| | - Gyun Min Lee
- Department of Biological Sciences, KAIST, Daejeon 34141, South Korea
| | | | - Insung S Choi
- Center for Cell-Encapsulation Research, Department of Chemistry, KAIST, Daejeon 34141, South Korea; Department of Bio and Brain Engineering, KAIST, Daejeon 34141, South Korea.
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2
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Pan C, Mao S, Xiong Z, Chen Z, Xu N. Glutamate dehydrogenase: Potential therapeutic targets for neurodegenerative disease. Eur J Pharmacol 2023; 950:175733. [PMID: 37116563 DOI: 10.1016/j.ejphar.2023.175733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 03/31/2023] [Accepted: 04/17/2023] [Indexed: 04/30/2023]
Abstract
Glutamate dehydrogenase (GDH) is a key enzyme in mammalian glutamate metabolism. It is located at the intersection of multiple metabolic pathways and participates in a variety of cellular activities. GDH activity is strictly regulated by a variety of allosteric compounds. Here, we review the unique distribution and expressions of GDH in the brain nervous system. GDH plays an essential role in the glutamate-glutamine-GABA cycle between astrocytes and neurons. The dysfunction of GDH may induce the occurrence of many neurodegenerative diseases, such as Parkinson's disease, epilepsy, Alzheimer's disease, schizophrenia, and frontotemporal dementia. GDH activators and gene therapy have been found to protect neurons and improve motor disorders in neurodegenerative diseases caused by glutamate metabolism disorders. To date, no medicine has been discovered that specifically targets neurodegenerative diseases, although several potential medicines are used clinically. Targeting GDH to treat neurodegenerative diseases is expected to provide new insights and treatment strategies.
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Affiliation(s)
- Chuqiao Pan
- College of Pharmaceutical Science, Institute of Drug Development & Chemical Biology, Zhejiang University of Technology, Huzhou, 313200, Zhejiang, People's Republic of China
| | - Shijie Mao
- College of Pharmaceutical Science, Institute of Drug Development & Chemical Biology, Zhejiang University of Technology, Huzhou, 313200, Zhejiang, People's Republic of China
| | - Zeping Xiong
- Department of Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Huzhou, 313200, Zhejiang, People's Republic of China
| | - Zhao Chen
- College of Pharmaceutical Science, Institute of Drug Development & Chemical Biology, Zhejiang University of Technology, Huzhou, 313200, Zhejiang, People's Republic of China
| | - Ning Xu
- College of Pharmaceutical Science, Institute of Drug Development & Chemical Biology, Zhejiang University of Technology, Huzhou, 313200, Zhejiang, People's Republic of China.
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3
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The Role of Glutamate Receptors in Epilepsy. Biomedicines 2023; 11:biomedicines11030783. [PMID: 36979762 PMCID: PMC10045847 DOI: 10.3390/biomedicines11030783] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/26/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Glutamate is an essential excitatory neurotransmitter in the central nervous system, playing an indispensable role in neuronal development and memory formation. The dysregulation of glutamate receptors and the glutamatergic system is involved in numerous neurological and psychiatric disorders, especially epilepsy. There are two main classes of glutamate receptor, namely ionotropic and metabotropic (mGluRs) receptors. The former stimulate fast excitatory neurotransmission, are N-methyl-d-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), and kainate; while the latter are G-protein-coupled receptors that mediate glutamatergic activity via intracellular messenger systems. Glutamate, glutamate receptors, and regulation of astrocytes are significantly involved in the pathogenesis of acute seizure and chronic epilepsy. Some glutamate receptor antagonists have been shown to be effective for the treatment of epilepsy, and research and clinical trials are ongoing.
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4
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Heit BS, Chu A, Sane A, Featherstone DE, Park TJ, Larson J. Tonic extracellular glutamate and ischaemia: glutamate antiporter system x c - regulates anoxic depolarization in hippocampus. J Physiol 2023; 601:607-629. [PMID: 36321247 PMCID: PMC10107724 DOI: 10.1113/jp283880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 10/18/2022] [Indexed: 12/05/2022] Open
Abstract
In stroke, the sudden deprivation of oxygen to neurons triggers a profuse release of glutamate that induces anoxic depolarization (AD) and leads to rapid cell death. Importantly, the latency of the glutamate-driven AD event largely dictates subsequent tissue damage. Although the contribution of synaptic glutamate during ischaemia is well-studied, the role of tonic (ambient) glutamate has received far less scrutiny. The majority of tonic, non-synaptic glutamate in the brain is governed by the cystine/glutamate antiporter, system xc - . Employing hippocampal slice electrophysiology, we showed that transgenic mice lacking a functional system xc - display longer latencies to AD and altered depolarizing waves compared to wild-type mice after total oxygen deprivation. Experiments which pharmacologically inhibited system xc - , as well as those manipulating tonic glutamate levels and those antagonizing glutamate receptors, revealed that the antiporter's putative effect on ambient glutamate precipitates the ischaemic cascade. As such, the current study yields novel insight into the pathogenesis of acute stroke and may direct future therapeutic interventions. KEY POINTS: Ischaemic stroke remains the leading cause of adult disability in the world, but efforts to reduce stroke severity have been plagued by failed translational attempts to mitigate glutamate excitotoxicity. Elucidating the ischaemic cascade, which within minutes leads to irreversible tissue damage induced by anoxic depolarization, must be a principal focus. Data presented here show that tonic, extrasynaptic glutamate supplied by system xc - synergizes with ischaemia-induced synaptic glutamate release to propagate AD and exacerbate depolarizing waves. Exploiting the role of system xc - and its obligate release of ambient glutamate could, therefore, be a novel therapeutic direction to attenuate the deleterious effects of acute stroke.
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Affiliation(s)
- Bradley S Heit
- Graduate Program in Neuroscience, University of Illinois at Chicago, Chicago, IL, USA.,Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, USA
| | - Alex Chu
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, USA
| | - Abhay Sane
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, USA
| | - David E Featherstone
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Thomas J Park
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - John Larson
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, USA.,Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
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5
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Cuellar-Santoyo AO, Ruiz-Rodríguez VM, Mares-Barbosa TB, Patrón-Soberano A, Howe AG, Portales-Pérez DP, Miquelajáuregui Graf A, Estrada-Sánchez AM. Revealing the contribution of astrocytes to glutamatergic neuronal transmission. Front Cell Neurosci 2023; 16:1037641. [PMID: 36744061 PMCID: PMC9893894 DOI: 10.3389/fncel.2022.1037641] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 12/20/2022] [Indexed: 01/20/2023] Open
Abstract
Research on glutamatergic neurotransmission has focused mainly on the function of presynaptic and postsynaptic neurons, leaving astrocytes with a secondary role only to ensure successful neurotransmission. However, recent evidence indicates that astrocytes contribute actively and even regulate neuronal transmission at different levels. This review establishes a framework by comparing glutamatergic components between neurons and astrocytes to examine how astrocytes modulate or otherwise influence neuronal transmission. We have included the most recent findings about the role of astrocytes in neurotransmission, allowing us to understand the complex network of neuron-astrocyte interactions. However, despite the knowledge of synaptic modulation by astrocytes, their contribution to specific physiological and pathological conditions remains to be elucidated. A full understanding of the astrocyte's role in neuronal processing could open fruitful new frontiers in the development of therapeutic applications.
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Affiliation(s)
- Ares Orlando Cuellar-Santoyo
- División de Biología Molecular, Laboratorio de Neurobiología, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), San Luis Potosí, Mexico
| | - Victor Manuel Ruiz-Rodríguez
- División de Biología Molecular, Laboratorio de Neurobiología, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), San Luis Potosí, Mexico
| | - Teresa Belem Mares-Barbosa
- División de Biología Molecular, Laboratorio de Neurobiología, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), San Luis Potosí, Mexico,Translational and Molecular Medicine Laboratory, Research Center for Health Sciences and Biomedicine, Autonomous University of San Luis Potosí, San Luis Potosí, Mexico
| | - Araceli Patrón-Soberano
- División de Biología Molecular, Laboratorio de Neurobiología, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), San Luis Potosí, Mexico
| | - Andrew G. Howe
- Intelligent Systems Laboratory, HRL Laboratories, LLC, Malibu, CA, United States
| | - Diana Patricia Portales-Pérez
- Translational and Molecular Medicine Laboratory, Research Center for Health Sciences and Biomedicine, Autonomous University of San Luis Potosí, San Luis Potosí, Mexico
| | | | - Ana María Estrada-Sánchez
- División de Biología Molecular, Laboratorio de Neurobiología, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), San Luis Potosí, Mexico,*Correspondence: Ana María Estrada-Sánchez
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6
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Velloso FJ, Shankar S, Parpura V, Rakic P, Levison SW. Neural Stem Cells in Adult Mammals are not Astrocytes. ASN Neuro 2022; 14:17590914221134739. [PMID: 36330653 PMCID: PMC9638700 DOI: 10.1177/17590914221134739] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 09/27/2022] [Accepted: 10/01/2022] [Indexed: 11/06/2022] Open
Abstract
At the turn of the 21st century studies of the cells that resided in the adult mammalian subventricular zone (SVZ) characterized the neural stem cells (NSCs) as a subtype of astrocyte. Over the ensuing years, numerous studies have further characterized the properties of these NSCs and compared them to parenchymal astrocytes. Here we have evaluated the evidence collected to date to establish whether classifying the NSCs as astrocytes is appropriate and useful. We also performed a meta-analysis with 4 previously published datasets that used cell sorting and unbiased single-cell RNAseq to highlight the distinct gene expression profiles of adult murine NSCs and niche astrocytes. On the basis of our understanding of the properties and functions of astrocytes versus the properties and functions of NSCs, and from our comparative transcriptomic analyses we conclude that classifying the adult mammalian NSC as an astrocyte is potentially misleading. From our vantage point, it is more appropriate to refer to the cells in the adult mammalian SVZ that retain the capacity to produce new neurons and macroglia as NSCs without attaching the term "astrocyte-like."
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Affiliation(s)
- Fernando Janczur Velloso
- Department of Pharmacology, Physiology & Neuroscience, New
Jersey Medical School, Rutgers University, Newark, NJ, USA
| | - Sandhya Shankar
- Department of Pharmacology, Physiology & Neuroscience, New
Jersey Medical School, Rutgers University, Newark, NJ, USA
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham,
Birmingham, AL, USA
| | - Pasko Rakic
- Department of Neuroscience, Yale School of Medicine, New Haven, CT,
USA
- Kavli Institute for Neuroscience, Yale School of Medicine, New
Haven, CT, USA
| | - Steven W. Levison
- Department of Pharmacology, Physiology & Neuroscience, New
Jersey Medical School, Rutgers University, Newark, NJ, USA
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7
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Yoon SR, Hong N, Lee MY, Ahn JC. Photobiomodulation with a 660-Nanometer Light-Emitting Diode Promotes Cell Proliferation in Astrocyte Culture. Cells 2021; 10:1664. [PMID: 34359834 PMCID: PMC8307591 DOI: 10.3390/cells10071664] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 12/17/2022] Open
Abstract
Astrocytes act as neural stem cells (NSCs) that have the potential to self-renew and differentiate into other neuronal cells. The protein expression of these astrocytes depends on the stage of differentiation, showing sequential expression of multiple proteins such as octamer-binding transcription factor 4 (Oct4), nestin, glial fibrillary acidic protein (GFAP), and aldehyde dehydrogenase 1 family member L1 (aldh1L1). Photobiomodulation (PBM) affects cell apoptosis, proliferation, migration, and adhesion. We hypothesized that astrocyte proliferation and differentiation would be modulated by PBM. We used an optimized astrocyte culture method and a 660-nanometer light-emitting diode (LED) to enhance the biological actions of many kinds of cells. We determined that the 660-nanometer LED promoted the biological actions of cultured astrocytes by increasing the reactive oxygen species levels. The overall viability of the cultured cells, which included various cells other than astrocytes, did not change after LED exposure; however, astrocyte-specific proliferation was observed by the increased co-expression of GFAP and bromodeoxyuridine (BrdU)/Ki67. Furthermore, the 660-nanometer LED provides evidence of differentiation, as shown by the decreased Oct4 and GFAP co-expression and increased nestin and aldh1L1 expression. These results demonstrate that a 660-nanometer LED can modify astrocyte proliferation, which suggests the efficacy of the therapeutic application of LED in various pathological states of the central nervous system.
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Affiliation(s)
- Sung-Ryeong Yoon
- Department of Medical Laser, Graduate School of Medicine, Dankook University, Cheonan 31116, Korea;
- Medical Laser Research Center, College of Medicine, Dankook University, Cheonan 31116, Korea;
| | - Namgue Hong
- Medical Laser Research Center, College of Medicine, Dankook University, Cheonan 31116, Korea;
| | - Min-Young Lee
- Department of Otolaryngology-Head & Neck Surgery, College of Medicine, Dankook University, Cheonan 31116, Korea
- Beckman Laser Institute Korea, College of Medicine, Dankook University, Cheonan 31116, Korea
| | - Jin-Chul Ahn
- Department of Medical Laser, Graduate School of Medicine, Dankook University, Cheonan 31116, Korea;
- Medical Laser Research Center, College of Medicine, Dankook University, Cheonan 31116, Korea;
- Beckman Laser Institute Korea, College of Medicine, Dankook University, Cheonan 31116, Korea
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8
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Hippocampal astrocytic neogenin regulating glutamate uptake, a critical pathway for preventing epileptic response. Proc Natl Acad Sci U S A 2021; 118:2022921118. [PMID: 33850017 DOI: 10.1073/pnas.2022921118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Epilepsy, a common neurological disorder, is featured with recurrent seizures. Its underlying pathological mechanisms remain elusive. Here, we provide evidence for loss of neogenin (NEO1), a coreceptor for multiple ligands, including netrins and bone morphological proteins, in the development of epilepsy. NEO1 is reduced in hippocampi from patients with epilepsy based on transcriptome and proteomic analyses. Neo1 knocking out (KO) in mouse brains displays elevated epileptiform spikes and seizure susceptibility. These phenotypes were undetectable in mice, with selectively depleted NEO1 in excitatory (NeuroD6-Cre+) or inhibitory (parvalbumin+) neurons, but present in mice with specific hippocampal astrocytic Neo1 KO. Additionally, neurons in hippocampal dentate gyrus, a vulnerable region in epilepsy, in mice with astrocyte-specific Neo1 KO show reductions in inhibitory synaptic vesicles and the frequency of miniature inhibitory postsynaptic current(mIPSC), but increase of the duration of miniature excitatory postsynaptic current and tonic NMDA receptor currents, suggesting impairments in both GABAergic transmission and extracellular glutamate clearance. Further proteomic and cell biological analyses of cell-surface proteins identified GLAST, a glutamate-aspartate transporter that is marked reduced in Neo1 KO astrocytes and the hippocampus. NEO1 interacts with GLAST and promotes GLAST surface distribution in astrocytes. Expressing NEO1 or GLAST in Neo1 KO astrocytes in the hippocampus abolishes the epileptic phenotype. Taken together, these results uncover an unrecognized pathway of NEO1-GLAST in hippocampal GFAP+ astrocytes, which is critical for GLAST surface distribution and function, and GABAergic transmission, unveiling NEO1 as a valuable therapeutic target to protect the brain from epilepsy.
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9
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Rurak GM, Woodside B, Aguilar-Valles A, Salmaso N. Astroglial cells as neuroendocrine targets in forebrain development: Implications for sex differences in psychiatric disease. Front Neuroendocrinol 2021; 60:100897. [PMID: 33359797 DOI: 10.1016/j.yfrne.2020.100897] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/05/2020] [Accepted: 12/15/2020] [Indexed: 12/23/2022]
Abstract
Astroglial cells are the most abundant cell type in the mammalian brain. They are implicated in almost every aspect of brain physiology, including maintaining homeostasis, building and maintaining the blood brain barrier, and the development and maturation of neuronal networks. Critically, astroglia also express receptors for gonadal sex hormones, respond rapidly to gonadal hormones, and are able to synthesize hormones. Thus, they are positioned to guide and mediate sexual differentiation of the brain, particularly neuronal networks in typical and pathological conditions. In this review, we describe astroglial involvement in the organization and development of the brain, and consider known sex differences in astroglial responses to understand how astroglial cell-mediated organization may play a role in forebrain sexual dimorphisms in human populations. Finally, we consider how sexually dimorphic astroglial responses and functions in development may lead to sex differences in vulnerability for neuropsychiatric disorders.
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Affiliation(s)
- Gareth M Rurak
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Barbara Woodside
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada; Concordia University, Montreal, Quebec, Canada
| | | | - Natalina Salmaso
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada.
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10
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Belov Kirdajova D, Kriska J, Tureckova J, Anderova M. Ischemia-Triggered Glutamate Excitotoxicity From the Perspective of Glial Cells. Front Cell Neurosci 2020; 14:51. [PMID: 32265656 PMCID: PMC7098326 DOI: 10.3389/fncel.2020.00051] [Citation(s) in RCA: 185] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/21/2020] [Indexed: 12/21/2022] Open
Abstract
A plethora of neurological disorders shares a final common deadly pathway known as excitotoxicity. Among these disorders, ischemic injury is a prominent cause of death and disability worldwide. Brain ischemia stems from cardiac arrest or stroke, both responsible for insufficient blood supply to the brain parenchyma. Glucose and oxygen deficiency disrupts oxidative phosphorylation, which results in energy depletion and ionic imbalance, followed by cell membrane depolarization, calcium (Ca2+) overload, and extracellular accumulation of excitatory amino acid glutamate. If tight physiological regulation fails to clear the surplus of this neurotransmitter, subsequent prolonged activation of glutamate receptors forms a vicious circle between elevated concentrations of intracellular Ca2+ ions and aberrant glutamate release, aggravating the effect of this ischemic pathway. The activation of downstream Ca2+-dependent enzymes has a catastrophic impact on nervous tissue leading to cell death, accompanied by the formation of free radicals, edema, and inflammation. After decades of “neuron-centric” approaches, recent research has also finally shed some light on the role of glial cells in neurological diseases. It is becoming more and more evident that neurons and glia depend on each other. Neuronal cells, astrocytes, microglia, NG2 glia, and oligodendrocytes all have their roles in what is known as glutamate excitotoxicity. However, who is the main contributor to the ischemic pathway, and who is the unsuspecting victim? In this review article, we summarize the so-far-revealed roles of cells in the central nervous system, with particular attention to glial cells in ischemia-induced glutamate excitotoxicity, its origins, and consequences.
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Affiliation(s)
- Denisa Belov Kirdajova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jan Kriska
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Jana Tureckova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia
| | - Miroslava Anderova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic (ASCR), Prague, Czechia.,Second Faculty of Medicine, Charles University, Prague, Czechia
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11
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Juneja DS, Nasuto S, Delivopoulos E. Fast and Efficient Differentiation of Mouse Embryonic Stem Cells Into ATP-Responsive Astrocytes. Front Cell Neurosci 2020; 13:579. [PMID: 32038173 PMCID: PMC6985097 DOI: 10.3389/fncel.2019.00579] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 12/16/2019] [Indexed: 12/25/2022] Open
Abstract
Astrocytes are multifunctional cells in the CNS, involved in the regulation of neurovascular coupling, the modulation of electrolytes, and the cycling of neurotransmitters at synapses. Induction of astrocytes from stem cells remains a largely underdeveloped area, as current protocols are time consuming, lack granularity in astrocytic subtype generation, and often are not as efficient as neural induction methods. In this paper we present an efficient method to differentiate astrocytes from mouse embryonic stem cells. Our technique uses a cell suspension protocol to produce embryoid bodies (EBs) that are neurally inducted and seeded onto laminin coated surfaces. Plated EBs attach to the surface and release migrating cells to their surrounding environment, which are further inducted into the astrocytic lineage, through an optimized, heparin-based media. Characterization and functional assessment of the cells consists of immunofluorescent labeling for specific astrocytic proteins and sensitivity to adenosine triphosphate (ATP) stimulation. Our experimental results show that even at the earliest stages of the protocol, cells are positive for astrocytic markers (GFAP, ALDH1L1, S100β, and GLAST) with variant expression patterns and purinergic receptors (P2Y). Generated astrocytes also exhibit differential Ca2+ transients upon stimulation with ATP, which evolve over the differentiation period. Metabotropic purinoceptors P2Y1R are expressed and we offer preliminary evidence that metabotropic purinoceptors contribute to Ca2+ transients. Our protocol is simple, efficient and fast, facilitating its use in multiple investigations, particularly in vitro studies of engineered neural networks.
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12
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Pajarillo E, Rizor A, Lee J, Aschner M, Lee E. The role of astrocytic glutamate transporters GLT-1 and GLAST in neurological disorders: Potential targets for neurotherapeutics. Neuropharmacology 2019; 161:107559. [PMID: 30851309 PMCID: PMC6731169 DOI: 10.1016/j.neuropharm.2019.03.002] [Citation(s) in RCA: 206] [Impact Index Per Article: 41.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/28/2019] [Accepted: 03/02/2019] [Indexed: 12/12/2022]
Abstract
Glutamate is the primary excitatory neurotransmitter in the central nervous system (CNS) which initiates rapid signal transmission in the synapse before its re-uptake into the surrounding glia, specifically astrocytes. The astrocytic glutamate transporters glutamate-aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1) and their human homologs excitatory amino acid transporter 1 (EAAT1) and 2 (EAAT2), respectively, are the major transporters which take up synaptic glutamate to maintain optimal extracellular glutamic levels, thus preventing accumulation in the synaptic cleft and ensuing excitotoxicity. Growing evidence has shown that excitotoxicity is associated with various neurological disorders, including amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), manganism, ischemia, schizophrenia, epilepsy, and autism. While the mechanisms of neurological disorders are not well understood, the dysregulation of GLAST/GLT-1 may play a significant role in excitotoxicity and associated neuropathogenesis. The expression and function of GLAST/GLT-1 may be dysregulated at the genetic, epigenetic, transcriptional or translational levels, leading to high levels of extracellular glutamate and excitotoxicity. Consequently, understanding the regulatory mechanisms of GLAST/GLT-1 has been an area of interest in developing therapeutics for the treatment of neurological disorders. Pharmacological agents including β-lactam antibiotics, estrogen/selective estrogen receptor modulators (SERMs), growth factors, histone deacetylase inhibitors (HDACi), and translational activators have shown significant efficacy in enhancing the expression and function of GLAST/GLT-1 and glutamate uptake both in vitro and in vivo. This comprehensive review will discuss the regulatory mechanisms of GLAST/GLT-1, their association with neurological disorders, and the pharmacological agents which mediate their expression and function. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Affiliation(s)
- Edward Pajarillo
- Department of Pharmaceutical Sciences, College of Pharmacy, Florida A&M University, Tallahassee, FL, 32301, USA
| | - Asha Rizor
- Department of Pharmaceutical Sciences, College of Pharmacy, Florida A&M University, Tallahassee, FL, 32301, USA
| | - Jayden Lee
- Department of Speech, Language & Hearing Sciences, Boston University, Boston, MA, 02215, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Eunsook Lee
- Department of Pharmaceutical Sciences, College of Pharmacy, Florida A&M University, Tallahassee, FL, 32301, USA.
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13
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Malik AR, Willnow TE. Excitatory Amino Acid Transporters in Physiology and Disorders of the Central Nervous System. Int J Mol Sci 2019; 20:ijms20225671. [PMID: 31726793 PMCID: PMC6888459 DOI: 10.3390/ijms20225671] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/07/2019] [Accepted: 11/11/2019] [Indexed: 12/12/2022] Open
Abstract
Excitatory amino acid transporters (EAATs) encompass a class of five transporters with distinct expression in neurons and glia of the central nervous system (CNS). EAATs are mainly recognized for their role in uptake of the amino acid glutamate, the major excitatory neurotransmitter. EAATs-mediated clearance of glutamate released by neurons is vital to maintain proper glutamatergic signalling and to prevent toxic accumulation of this amino acid in the extracellular space. In addition, some EAATs also act as chloride channels or mediate the uptake of cysteine, required to produce the reactive oxygen speciesscavenger glutathione. Given their central role in glutamate homeostasis in the brain, as well as their additional activities, it comes as no surprise that EAAT dysfunctions have been implicated in numerous acute or chronic diseases of the CNS, including ischemic stroke and epilepsy, cerebellar ataxias, amyotrophic lateral sclerosis, Alzheimer’s disease and Huntington’s disease. Here we review the studies in cellular and animal models, as well as in humans that highlight the roles of EAATs in the pathogenesis of these devastating disorders. We also discuss the mechanisms regulating EAATs expression and intracellular trafficking and new exciting possibilities to modulate EAATs and to provide neuroprotection in course of pathologies affecting the CNS.
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Affiliation(s)
- Anna R. Malik
- Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
- Correspondence:
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14
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Prabhu D, Khan SM, Blackburn K, Marshall JP, Ashpole NM. Loss of insulin-like growth factor-1 signaling in astrocytes disrupts glutamate handling. J Neurochem 2019; 151:689-702. [PMID: 31563149 DOI: 10.1111/jnc.14879] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 09/04/2019] [Accepted: 09/17/2019] [Indexed: 12/25/2022]
Abstract
Insulin-like Growth Factor-1 (IGF-1) has been studied extensively for its ability to promote neuronal growth and excitability. Declining levels of IGF-1 have been correlated with impaired learning and memory as well as an increased risk of neurodegenerative diseases. While neuronal regulation by IGF-1 is well understood, the role of IGF-1 in influencing astrocyte function requires further exploration. Astrocytes regulate many aspects of the brain microenvironment, including controlling glutamate-glutamine cycling, which ultimately supports neuronal metabolism, neurotransmission, and protection from over stimulation. In this study, we examined whether IGF-1 acts through its cognate receptor, IGFR, to alter astrocytic glutamate handling. We utilized both small molecule IGFR inhibitors and Cre-driven genetic approaches to reduce IGFR in vivo and in cultured rodent astrocytes. When IGFR was knocked out of primary astrocytes derived from igfrf/f mice using AAV5-CMV-Cre, significant reductions in glutamate uptake were observed. Similarly, inhibition of IGFR with picropodophyllotoxin for 2 h, as well as 24 h, reduced glutamate uptake in vitro. Mechanistically, short-term inhibition of IGFR resulted in a significant decrease in glutamate transporter availability on the cell surface, as assessed by biotinylation. Long-term inhibition of IGFR led to significant reductions in mRNA expression of glutamate transport machinery, as assessed with qPCR. Reduced glutamate transporter mRNA was also observed in the brains of astrocyte-specific IGFR-deficient mice, three to four months after knock-out was induced with tamoxifen. Interestingly, long-term IGF-1 inhibition also resulted in an increase in adenosine triphosphate-stimulated glutamate release, though no change in adenosine triphosphate-stimulated calcium flux was observed nor were any changes in purinergic receptor protein expression. Together, these data suggest that reduced IGF-1 signaling will favor an accumulation of extrasynaptic glutamate, which may contribute to neurodegeneration in disease states where IGF-1 levels are low. Cover Image for this issue: doi: 10.1111/jnc.14534.
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Affiliation(s)
- Disha Prabhu
- Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, University, Mississippi, USA
| | - Sariya M Khan
- Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, University, Mississippi, USA
| | - Katherine Blackburn
- Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, University, Mississippi, USA
| | - Jessica P Marshall
- Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, University, Mississippi, USA
| | - Nicole M Ashpole
- Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, University, Mississippi, USA.,Research Institute of Pharmaceutical Sciences, University of Mississippi School of Pharmacy, University, Mississippi, USA
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15
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Prabhu D, Khan SM, Blackburn K, Marshall JP, Ashpole NM. Loss of insulin-like growth factor-1 signaling in astrocytes disrupts glutamate handling. J Neurochem 2019. [PMID: 31563149 DOI: 10.1111/jnc.14534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Insulin-like Growth Factor-1 (IGF-1) has been studied extensively for its ability to promote neuronal growth and excitability. Declining levels of IGF-1 have been correlated with impaired learning and memory as well as an increased risk of neurodegenerative diseases. While neuronal regulation by IGF-1 is well understood, the role of IGF-1 in influencing astrocyte function requires further exploration. Astrocytes regulate many aspects of the brain microenvironment, including controlling glutamate-glutamine cycling, which ultimately supports neuronal metabolism, neurotransmission, and protection from over stimulation. In this study, we examined whether IGF-1 acts through its cognate receptor, IGFR, to alter astrocytic glutamate handling. We utilized both small molecule IGFR inhibitors and Cre-driven genetic approaches to reduce IGFR in vivo and in cultured rodent astrocytes. When IGFR was knocked out of primary astrocytes derived from igfrf/f mice using AAV5-CMV-Cre, significant reductions in glutamate uptake were observed. Similarly, inhibition of IGFR with picropodophyllotoxin for 2 h, as well as 24 h, reduced glutamate uptake in vitro. Mechanistically, short-term inhibition of IGFR resulted in a significant decrease in glutamate transporter availability on the cell surface, as assessed by biotinylation. Long-term inhibition of IGFR led to significant reductions in mRNA expression of glutamate transport machinery, as assessed with qPCR. Reduced glutamate transporter mRNA was also observed in the brains of astrocyte-specific IGFR-deficient mice, three to four months after knock-out was induced with tamoxifen. Interestingly, long-term IGF-1 inhibition also resulted in an increase in adenosine triphosphate-stimulated glutamate release, though no change in adenosine triphosphate-stimulated calcium flux was observed nor were any changes in purinergic receptor protein expression. Together, these data suggest that reduced IGF-1 signaling will favor an accumulation of extrasynaptic glutamate, which may contribute to neurodegeneration in disease states where IGF-1 levels are low. Cover Image for this issue: doi: 10.1111/jnc.14534.
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Affiliation(s)
- Disha Prabhu
- Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, University, Mississippi, USA
| | - Sariya M Khan
- Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, University, Mississippi, USA
| | - Katherine Blackburn
- Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, University, Mississippi, USA
| | - Jessica P Marshall
- Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, University, Mississippi, USA
| | - Nicole M Ashpole
- Department of BioMolecular Sciences, University of Mississippi School of Pharmacy, University, Mississippi, USA.,Research Institute of Pharmaceutical Sciences, University of Mississippi School of Pharmacy, University, Mississippi, USA
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16
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Garcia-Esparcia P, Diaz-Lucena D, Ainciburu M, Torrejón-Escribano B, Carmona M, Llorens F, Ferrer I. Glutamate Transporter GLT1 Expression in Alzheimer Disease and Dementia With Lewy Bodies. Front Aging Neurosci 2018; 10:122. [PMID: 29755340 PMCID: PMC5932187 DOI: 10.3389/fnagi.2018.00122] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 04/11/2018] [Indexed: 01/23/2023] Open
Abstract
Glutamate transporter solute carrier family 1, member 2 (GLT1/EAAT2), a major modulator of glutamate homeostasis in astrocytes, is assessed in post-mortem human brain samples of frontal cortex area 8 in advanced stages of Alzheimer disease (AD) and terminal stages of dementia with Lewy bodies (DLB) in order to gain understanding of astrogliopathy in diseases manifested by dementia. Glial fibrillary acidic protein (GFAP) mRNA expression is significantly increased in AD but not in DLB, whereas GLT1, vesicular glutamate transporter 1 (vGLUT1) and aldehyde dehydrogenase 1 family member 1 (ALDH1L1) are not modified in AD and DLB when compared with controls. GLT1 protein levels are not altered in AD and DLB but GFAP and ALDH1L1 are significantly increased in AD, and GFAP in DLB. As a result, a non-significant decrease in the ratio between GLT1 and GFAP, and between GLT1 and ALDH1L1, is found in both AD and DLB. Double-labeling immunofluorescence and confocal microscopy revealed no visible reduction of GLT1 immunoreactivity in relation to β-amyloid plaques in AD. These data suggest a subtle imbalance between GLT1, and GFAP and ALDH1L1 expression, with limited consequences in glutamate transport.
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Affiliation(s)
- Paula Garcia-Esparcia
- Department of Pathology and Experimental Therapeutics, University of Barcelona, Hospitalet de Llobregat, Barcelona, Spain.,CIBERNED (Biomedical Network Research Centre of Neurodegenerative Diseases), Institute of Health Carlos III, Madrid, Spain
| | - Daniela Diaz-Lucena
- CIBERNED (Biomedical Network Research Centre of Neurodegenerative Diseases), Institute of Health Carlos III, Madrid, Spain
| | - Marina Ainciburu
- Department of Pathology and Experimental Therapeutics, University of Barcelona, Hospitalet de Llobregat, Barcelona, Spain
| | - Benjamin Torrejón-Escribano
- Biology Unit, Scientific and Technical Services, University of Barcelona, Hospitalet de Llobregat, Barcelona, Spain
| | - Margarita Carmona
- Department of Pathology and Experimental Therapeutics, University of Barcelona, Hospitalet de Llobregat, Barcelona, Spain.,CIBERNED (Biomedical Network Research Centre of Neurodegenerative Diseases), Institute of Health Carlos III, Madrid, Spain
| | - Franc Llorens
- CIBERNED (Biomedical Network Research Centre of Neurodegenerative Diseases), Institute of Health Carlos III, Madrid, Spain.,Bellvitge Biomedical Research Institute, l'Hospitalet de Llobregat (IDIBELL), Barcelona, Spain
| | - Isidro Ferrer
- Department of Pathology and Experimental Therapeutics, University of Barcelona, Hospitalet de Llobregat, Barcelona, Spain.,CIBERNED (Biomedical Network Research Centre of Neurodegenerative Diseases), Institute of Health Carlos III, Madrid, Spain.,Senior Consultant Service of Pathology, Bellvitge University Hospital, IDIBELL, Hospitalet de Llobregat, Barcelona, Spain.,Institute of Neurosciences, University of Barcelona, Barcelona, Spain
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17
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Rose CR, Ziemens D, Untiet V, Fahlke C. Molecular and cellular physiology of sodium-dependent glutamate transporters. Brain Res Bull 2016; 136:3-16. [PMID: 28040508 DOI: 10.1016/j.brainresbull.2016.12.013] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/20/2016] [Accepted: 12/21/2016] [Indexed: 02/04/2023]
Abstract
Glutamate is the major excitatory transmitter in the vertebrate brain. After its release from presynaptic nerve terminals, it is rapidly taken up by high-affinity sodium-dependent plasma membrane transporters. While both neurons and glial cells express these excitatory amino acid transporters (EAATs), the majority of glutamate uptake is accomplished by astrocytes, which convert synaptically-released glutamate to glutamine or feed it into their own metabolism. Glutamate uptake by astrocytes not only shapes synaptic transmission by regulating the availability of glutamate to postsynaptic neuronal receptors, but also protects neurons from hyper-excitability and subsequent excitotoxic damage. In the present review, we provide an overview of the molecular and cellular characteristics of sodium-dependent glutamate transporters and their associated anion permeation pathways, with a focus on astrocytic glutamate transport. We summarize their functional properties and roles within tripartite synapses under physiological and pathophysiological conditions, exemplifying the intricate interactions and interrelationships between neurons and glial cells in the brain.
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Affiliation(s)
- Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany.
| | - Daniel Ziemens
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, Germany
| | - Verena Untiet
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, Germany
| | - Christoph Fahlke
- Institute of Complex Systems, Zelluläre Biophysik (ICS-4), Forschungszentrum Jülich, Germany
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18
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Engel M, Do-Ha D, Muñoz SS, Ooi L. Common pitfalls of stem cell differentiation: a guide to improving protocols for neurodegenerative disease models and research. Cell Mol Life Sci 2016; 73:3693-709. [PMID: 27154043 PMCID: PMC5002043 DOI: 10.1007/s00018-016-2265-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/05/2016] [Accepted: 05/03/2016] [Indexed: 12/17/2022]
Abstract
Induced pluripotent stem cells and embryonic stem cells have revolutionized cellular neuroscience, providing the opportunity to model neurological diseases and test potential therapeutics in a pre-clinical setting. The power of these models has been widely discussed, but the potential pitfalls of stem cell differentiation in this research are less well described. We have analyzed the literature that describes differentiation of human pluripotent stem cells into three neural cell types that are commonly used to study diseases, including forebrain cholinergic neurons for Alzheimer's disease, midbrain dopaminergic neurons for Parkinson's disease and cortical astrocytes for neurodegenerative and psychiatric disorders. Published protocols for differentiation vary widely in the reported efficiency of target cell generation. Additionally, characterization of the cells by expression profile and functionality differs between studies and is often insufficient, leading to highly variable protocol outcomes. We have synthesized this information into a simple methodology that can be followed when performing or assessing differentiation techniques. Finally we propose three considerations for future research, including the use of physiological O2 conditions, three-dimensional co-culture systems and microfluidics to control feeding cycles and growth factor gradients. Following these guidelines will help researchers to ensure that robust and meaningful data is generated, enabling the full potential of stem cell differentiation for disease modeling and regenerative medicine.
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Affiliation(s)
- Martin Engel
- Illawarra Health and Medical Research Institute, School of Biological Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Dzung Do-Ha
- Illawarra Health and Medical Research Institute, School of Biological Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Sonia Sanz Muñoz
- Illawarra Health and Medical Research Institute, School of Biological Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia
| | - Lezanne Ooi
- Illawarra Health and Medical Research Institute, School of Biological Sciences, Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, NSW, Australia.
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19
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Astroglial glutamate transporters coordinate excitatory signaling and brain energetics. Neurochem Int 2016; 98:56-71. [PMID: 27013346 DOI: 10.1016/j.neuint.2016.03.014] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/15/2016] [Accepted: 03/17/2016] [Indexed: 12/22/2022]
Abstract
In the mammalian brain, a family of sodium-dependent transporters maintains low extracellular glutamate and shapes excitatory signaling. The bulk of this activity is mediated by the astroglial glutamate transporters GLT-1 and GLAST (also called EAAT2 and EAAT1). In this review, we will discuss evidence that these transporters co-localize with, form physical (co-immunoprecipitable) interactions with, and functionally couple to various 'energy-generating' systems, including the Na(+)/K(+)-ATPase, the Na(+)/Ca(2+) exchanger, glycogen metabolizing enzymes, glycolytic enzymes, and mitochondria/mitochondrial proteins. This functional coupling is bi-directional with many of these systems both being regulated by glutamate transport and providing the 'fuel' to support glutamate uptake. Given the importance of glutamate uptake to maintaining synaptic signaling and preventing excitotoxicity, it should not be surprising that some of these systems appear to 'redundantly' support the energetic costs of glutamate uptake. Although the glutamate-glutamine cycle contributes to recycling of neurotransmitter pools of glutamate, this is an over-simplification. The ramifications of co-compartmentalization of glutamate transporters with mitochondria for glutamate metabolism are discussed. Energy consumption in the brain accounts for ∼20% of the basal metabolic rate and relies almost exclusively on glucose for the production of ATP. However, the brain does not possess substantial reserves of glucose or other fuels. To ensure adequate energetic supply, increases in neuronal activity are matched by increases in cerebral blood flow via a process known as 'neurovascular coupling'. While the mechanisms for this coupling are not completely resolved, it is generally agreed that astrocytes, with processes that extend to synapses and endfeet that surround blood vessels, mediate at least some of the signal that causes vasodilation. Several studies have shown that either genetic deletion or pharmacologic inhibition of glutamate transport impairs neurovascular coupling. Together these studies strongly suggest that glutamate transport not only coordinates excitatory signaling, but also plays a pivotal role in regulating brain energetics.
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20
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Hacimuftuoglu A, Tatar A, Cetin D, Taspinar N, Saruhan F, Okkay U, Turkez H, Unal D, Stephens RL, Suleyman H. Astrocyte/neuron ratio and its importance on glutamate toxicity: an in vitro voltammetric study. Cytotechnology 2015; 68:1425-33. [PMID: 26438331 DOI: 10.1007/s10616-015-9902-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 07/09/2015] [Indexed: 01/05/2023] Open
Abstract
The purpose of this study was to clarify the relationship between neuron cells and astrocyte cells in regulating glutamate toxicity on the 10th and 20th day in vitro. A mixed primary culture system from newborn rats that contain cerebral cortex neurons cells was employed to investigate the glutamate toxicity. All cultures were incubated with various glutamate concentrations, then viability tests and histological analyses were performed. The activities of glutamate transporters were determined by using in vitro voltammetry technique. Viable cell number was decreased significantly on the 10th day at 10(-7) M and at 10(-6) M glutamate applications, however, viable cell number was not decreased at 20th day. Astrocyte number was increased nearly six times on the 20th day as compared to the 10th day. The peak point of glutamate reuptake capacity was about 2 × 10(-4) M on the 10th day and 10(-3) M on the 20th day. According to our results, we suggested that astrocyte age was important to maintain neuronal survival against glutamate toxicity. Thus, we revealed activation or a trigger point of glutamate transporters on astrocytes due to time since more glutamate was taken up by astrocytes when glutamate transporters on the astrocyte were triggered with high exogenous glutamate concentrations. In conclusion, the present investigation is the first voltammetric study on the reuptake parameters of glutamate in vitro.
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Affiliation(s)
- Ahmet Hacimuftuoglu
- Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey.
| | - Abdulgani Tatar
- Department of Medical Genetics, Faculty of Medicine, Ataturk University, Erzurum, Turkey
| | - Damla Cetin
- Department of Medical Pharmacology, Faculty of Medicine, Kafkas University, Kars, Turkey
| | - Numan Taspinar
- Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Fatih Saruhan
- Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Ufuk Okkay
- Department of Medical Pharmacology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Hasan Turkez
- Department of Molecular Biology and Genetics, Faculty of Sciences, Erzurum Technical University, Erzurum, Turkey.,Department of Pharmaceutical Sciences, University of "G. D'Annunzio", Chieti, Italy
| | - Deniz Unal
- Department of Histology, Faculty of Medicine, Ataturk University, Erzurum, Turkey
| | - Robert Louis Stephens
- Department of Physiology and Cell Biology, Medical College, The Ohio State University, Columbus, OH, USA
| | - Halis Suleyman
- Department of Medical Pharmacology, Faculty of Medicine, Erzincan University, Erzincan, Turkey
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21
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Molecular Biomarkers for Embryonic and Adult Neural Stem Cell and Neurogenesis. BIOMED RESEARCH INTERNATIONAL 2015; 2015:727542. [PMID: 26421301 PMCID: PMC4569757 DOI: 10.1155/2015/727542] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 11/19/2014] [Indexed: 02/07/2023]
Abstract
The procedure of neurogenesis has made numerous achievements in the past decades, during which various molecular biomarkers have been emerging and have been broadly utilized for the investigation of embryonic and adult neural stem cell (NSC). Nevertheless, there is not a consistent and systematic illustration to depict the functional characteristics of the specific markers expressed in distinct cell types during the different stages of neurogenesis. Here we gathered and generalized a series of NSC biomarkers emerging during the procedures of embryonic and adult neural stem cell, which may be used to identify the subpopulation cells with distinguishing characters in different timeframes of neurogenesis. The identifications of cell patterns will provide applications to the detailed investigations of diverse developmental cell stages and the extents of cell differentiation, which will facilitate the tracing of cell time-course and fate determination of specific cell types and promote the further and literal discoveries of embryonic and adult neurogenesis. Meanwhile, via the utilization of comprehensive applications under the aiding of the systematic knowledge framework, researchers may broaden their insights into the derivation and establishment of novel technologies to analyze the more detailed process of embryogenesis and adult neurogenesis.
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22
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Human glial progenitor engraftment and gene expression is independent of the ALS environment. Exp Neurol 2014; 264:188-99. [PMID: 25523812 DOI: 10.1016/j.expneurol.2014.12.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 11/22/2014] [Accepted: 12/07/2014] [Indexed: 12/12/2022]
Abstract
Although Amyotrophic Lateral Sclerosis (ALS) is a motor neuron disease, basic research studies have highlighted that astrocytes contribute to the disease process. Therefore, strategies which replace the diseased astrocyte population with healthy astrocytes may protect against motor neuron degeneration. Our studies have sought to evaluate astrocyte replacement using glial-restricted progenitors (GRPs), which are lineage-restricted precursors capable of differentiating into astrocytes after transplantation. The goal of our current study was to evaluate how transplantation to the diseased ALS spinal cord versus a healthy, wild-type spinal cord may affect human GRP engraftment and selected gene expression. Human GRPs were transplanted into the spinal cord of either an ALS mouse model or wild-type littermate mice. Mice were sacrificed for analysis at either the onset of disease course or at the endstage of disease. The transplanted GRPs were analyzed by immunohistochemistry and NanoString gene profiling which showed no gross differences in the engraftment or gene expression of the cells. Our data indicate that human glial progenitor engraftment and gene expression is independent of the neurodegenerative ALS spinal cord environment. These findings are of interest given that human GRPs are currently in clinical development for spinal cord transplantation into ALS patients.
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23
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Schreiner AE, Durry S, Aida T, Stock MC, Rüther U, Tanaka K, Rose CR, Kafitz KW. Laminar and subcellular heterogeneity of GLAST and GLT-1 immunoreactivity in the developing postnatal mouse hippocampus. J Comp Neurol 2014; 522:204-24. [PMID: 23939750 DOI: 10.1002/cne.23450] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 05/23/2013] [Accepted: 08/02/2013] [Indexed: 11/06/2022]
Abstract
Astrocytes express two sodium-coupled transporters, glutamate-aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1), which are essential for the maintenance of low extracellular glutamate levels. We performed a comparative analysis of the laminar and subcellular expression profile of GLAST and GLT-1 in the developing postnatal mouse hippocampus by using immunohistochemistry and western blotting and employing high-resolution fluorescence microscopy. Astrocytes were identified by costaining with glial fibrillary acidic protein (GFAP) or S100β. In CA1, the density of GFAP-positive cells and GFAP expression rose during the first 2 weeks after birth, paralleled by a steady increase in GLAST immunoreactivity and protein content. Upregulation of GLT-1 was completed only at postnatal days (P) P20-25 and was thus delayed by about 10 days. GLAST staining was highest along the stratum pyramidale and was especially prominent in astrocytes at P3-5. GLAST immunoreactivity indicated no preferential localization to a specific cellular compartment. GLT-1 exhibited a laminar expression pattern from P10-15 on, with the highest immunoreactivity in the stratum lacunosum-moleculare. At the cellular level, GLT-1 immunoreactivity did not entirely cover astrocyte somata and exhibited clusters at processes. In neonatal and juvenile animals, discrete clusters of GLT-1 were also detected at perivascular endfeet. From these results, we conclude there is a remarkable subcellular heterogeneity of GLAST and GLT-1 expression in the developing hippocampus. The clustering of GLT-1 at astrocyte endfeet indicates that it might serve a specialized functional role at the blood-brain barrier during formation of the hippocampal network.
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Affiliation(s)
- Alexandra E Schreiner
- Institute of Neurobiology, Heinrich Heine University Duesseldorf, 40225, Duesseldorf, Germany
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24
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Heterogeneous Cellular Distribution of Glutamate Dehydrogenase in Brain and in Non-neural Tissues. Neurochem Res 2014; 39:500-15. [DOI: 10.1007/s11064-013-1235-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Revised: 12/27/2013] [Accepted: 12/30/2013] [Indexed: 01/30/2023]
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25
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Okuda H, Tatsumi K, Morita S, Shibukawa Y, Korekane H, Horii-Hayashi N, Wada Y, Taniguchi N, Wanaka A. Chondroitin sulfate proteoglycan tenascin-R regulates glutamate uptake by adult brain astrocytes. J Biol Chem 2013; 289:2620-31. [PMID: 24337573 DOI: 10.1074/jbc.m113.504787] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
In our previous study, the CS-56 antibody, which recognizes a chondroitin sulfate moiety, labeled a subset of adult brain astrocytes, yielding a patchy extracellular matrix pattern. To explore the molecular nature of CS-56-labeled glycoproteins, we purified glycoproteins of the adult mouse cerebral cortex using a combination of anion-exchange, charge-transfer, and size-exclusion chromatographies. One of the purified proteins was identified as tenascin-R (TNR) by mass spectrometric analysis. When we compared TNR mRNA expression patterns with the distribution patterns of CS-56-positive cells, TNR mRNA was detected in CS-56-positive astrocytes. To examine the functions of TNR in astrocytes, we first confirmed that cultured astrocytes also expressed TNR protein. TNR knockdown by siRNA expression significantly reduced glutamate uptake in cultured astrocytes. Furthermore, expression of mRNA and protein of excitatory amino acid transporter 1 (GLAST), which is a major component of astrocytic glutamate transporters, was reduced by TNR knockdown. Our results suggest that TNR is expressed in a subset of astrocytes and contributes to glutamate homeostasis by regulating astrocytic GLAST expression.
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Affiliation(s)
- Hiroaki Okuda
- From the Departments of Anatomy and Neuroscience and
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26
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Human stem cell-derived spinal cord astrocytes with defined mature or reactive phenotypes. Cell Rep 2013; 4:1035-1048. [PMID: 23994478 DOI: 10.1016/j.celrep.2013.06.021] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 05/15/2013] [Accepted: 06/18/2013] [Indexed: 12/23/2022] Open
Abstract
Differentiation of astrocytes from human stem cells has significant potential for analysis of their role in normal brain function and disease, but existing protocols generate only immature astrocytes. Using early neuralization, we generated spinal cord astrocytes from mouse or human embryonic or induced pluripotent stem cells with high efficiency. Remarkably, short exposure to fibroblast growth factor 1 (FGF1) or FGF2 was sufficient to direct these astrocytes selectively toward a mature quiescent phenotype, as judged by both marker expression and functional analysis. In contrast, tumor necrosis factor alpha and interleukin-1β, but not FGFs, induced multiple elements of a reactive inflammatory phenotype but did not affect maturation. These phenotypically defined, scalable populations of spinal cord astrocytes will be important both for studying normal astrocyte function and for modeling human pathological processes in vitro.
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Candidate biomarker discovery for angiogenesis by automatic integration of Orbitrap MS1 spectral- and X!Tandem MS2 sequencing information. GENOMICS PROTEOMICS & BIOINFORMATICS 2013; 11:182-94. [PMID: 23557902 PMCID: PMC4357783 DOI: 10.1016/j.gpb.2013.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 02/21/2013] [Accepted: 02/28/2013] [Indexed: 02/06/2023]
Abstract
Candidate protein biomarker discovery by full automatic integration of Orbitrap full MS1 spectral peptide profiling and X!Tandem MS2 peptide sequencing is investigated by analyzing mass spectra from brain tumor samples using Peptrix. Potential protein candidate biomarkers found for angiogenesis are compared with those previously reported in the literature and obtained from previous Fourier transform ion cyclotron resonance (FT-ICR) peptide profiling. Lower mass accuracy of peptide masses measured by Orbitrap compared to those measured by FT-ICR is compensated by the larger number of detected masses separated by liquid chromatography (LC), which can be directly linked to protein identifications. The number of peptide sequences divided by the number of unique sequences is 9248/6911 ≈ 1.3. Peptide sequences appear 1.3 times redundant per up-regulated protein on average in the peptide profile matrix, and do not seem always up-regulated due to tailing in LC retention time (40%), modifications (40%) and mass determination errors (20%). Significantly up-regulated proteins found by integration of X!Tandem are described in the literature as tumor markers and some are linked to angiogenesis. New potential biomarkers are found, but need to be validated independently. Eventually more proteins could be found by actively involving MS2 sequence information in the creation of the MS1 peptide profile matrix.
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Komlos D, Mann KD, Zhuo Y, Ricupero CL, Hart RP, Liu AYC, Firestein BL. Glutamate dehydrogenase 1 and SIRT4 regulate glial development. Glia 2012; 61:394-408. [PMID: 23281078 DOI: 10.1002/glia.22442] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 10/22/2012] [Indexed: 01/10/2023]
Abstract
Congenital hyperinsulinism/hyperammonemia (HI/HA) syndrome is caused by an activation mutation of glutamate dehydrogenase 1 (GDH1), a mitochondrial enzyme responsible for the reversible interconversion between glutamate and α-ketoglutarate. The syndrome presents clinically with hyperammonemia, significant episodic hypoglycemia, seizures, and frequent incidences of developmental and learning defects. Clinical research has implicated that although some of the developmental and neurological defects may be attributed to hypoglycemia, some characteristics cannot be ascribed to low glucose and as hyperammonemia is generally mild and asymptomatic, there exists the possibility that altered GDH1 activity within the brain leads to some clinical changes. GDH1 is allosterically regulated by many factors, and has been shown to be inhibited by the ADP-ribosyltransferase sirtuin 4 (SIRT4), a mitochondrially localized sirtuin. Here we show that SIRT4 is localized to mitochondria within the brain. SIRT4 is highly expressed in glial cells, specifically astrocytes, in the postnatal brain and in radial glia during embryogenesis. Furthermore, SIRT4 protein decreases in expression during development. We show that factors known to allosterically regulate GDH1 alter gliogenesis in CTX8 cells, a novel radial glial cell line. We find that SIRT4 and GDH1 overexpression play antagonistic roles in regulating gliogenesis and that a mutant variant of GDH1 found in HI/HA patients accelerates the development of glia from cultured radial glia cells.
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Affiliation(s)
- Daniel Komlos
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey, USA
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Bristot Silvestrin R, Bambini-Junior V, Galland F, Daniele Bobermim L, Quincozes-Santos A, Torres Abib R, Zanotto C, Batassini C, Brolese G, Gonçalves CA, Riesgo R, Gottfried C. Animal model of autism induced by prenatal exposure to valproate: altered glutamate metabolism in the hippocampus. Brain Res 2012; 1495:52-60. [PMID: 23219577 DOI: 10.1016/j.brainres.2012.11.048] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 11/05/2012] [Accepted: 11/28/2012] [Indexed: 10/27/2022]
Abstract
Autism spectrum disorders (ASD) are characterized by deficits in social interaction, language and communication impairments and repetitive and stereotyped behaviors, with involvement of several areas of the central nervous system (CNS), including hippocampus. Although neurons have been the target of most studies reported in the literature, recently, considerable attention has been centered upon the functionality and plasticity of glial cells, particularly astrocytes. These cells participate in normal brain development and also in neuropathological processes. The present work investigated hippocampi from 15 (P15) and 120 (P120) days old male rats prenatally exposed to valproic acid (VPA) as an animal model of autism. Herein, we analyzed astrocytic parameters such as glutamate transporters and glutamate uptake, glutamine synthetase (GS) activity and glutathione (GSH) content. In the VPA group glutamate uptake was unchanged at P15 and increased 160% at P120; the protein expression of GLAST did not change neither in P15 nor in P120, while GLT1 decreased 40% at P15 and increased 92% at P120; GS activity increased 43% at P15 and decreased 28% at P120; GSH content was unaltered at P15 and had a 27% increase at P120. These data highlight that the astrocytic clearance and destination of glutamate in the synaptic cleft might be altered in autism, pointing out important aspects to be considered from both pathophysiologic and pharmacological approaches in ASD.
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Affiliation(s)
- Roberta Bristot Silvestrin
- Research Group in Neuroglial Plasticity at the Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Cavaliere C, Cirillo G, Bianco MR, Adriani W, De Simone A, Leo D, Perrone-Capano C, Papa M. Methylphenidate administration determines enduring changes in neuroglial network in rats. Eur Neuropsychopharmacol 2012; 22:53-63. [PMID: 21550213 DOI: 10.1016/j.euroneuro.2011.04.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Revised: 03/31/2011] [Accepted: 04/06/2011] [Indexed: 12/23/2022]
Abstract
Repeated exposure to psychostimulant drugs induces complex molecular and structural modifications in discrete brain regions of the meso-cortico-limbic system. This structural remodeling is thought to underlie neurobehavioral adaptive responses. Administration to adolescent rats of methylphenidate (MPH), commonly used in attention deficit and hyperactivity disorder (ADHD), triggers alterations of reward-based behavior paralleled by persistent and plastic synaptic changes of neuronal and glial markers within key areas of the reward circuits. By immunohistochemistry, we observe a marked increase of glial fibrillary acidic protein (GFAP) and neuronal nitric oxide synthase (nNOS) expression and a down-regulation of glial glutamate transporter GLAST in dorso-lateral and ventro-medial striatum. Using electron microscopy, we find in the prefrontal cortex a significant reduction of the synaptic active zone length, paralleled by an increase of dendritic spines. We demonstrate that in limbic areas the MPH-induced reactive astrocytosis affects the glial glutamatergic uptake system that in turn could determine glutamate receptor sensitization. These processes could be sustained by NO production and synaptic rearrangement and contribute to MPH neuroglial induced rewiring.
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Affiliation(s)
- Carlo Cavaliere
- Department of Medicina Pubblica Clinica e Preventiva, Second University of Naples, Naples, Italy
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Moussawi K, Riegel A, Nair S, Kalivas PW. Extracellular glutamate: functional compartments operate in different concentration ranges. Front Syst Neurosci 2011; 5:94. [PMID: 22275885 PMCID: PMC3254064 DOI: 10.3389/fnsys.2011.00094] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Accepted: 10/31/2011] [Indexed: 12/24/2022] Open
Abstract
Extracellular glutamate of glial origin modulates glial and neuronal glutamate release and synaptic plasticity. Estimates of the tonic basal concentration of extracellular glutamate range over three orders of magnitude (0.02-20 μM) depending on the technology employed to make the measurement. Based upon binding constants for glutamate receptors and transporters, this range of concentrations translates into distinct physiological and pathophysiological roles for extracellular glutamate. Here we speculate that the difference in glutamate measurements can be explained if there is patterned membrane surface expression of glutamate release and transporter sites creating extracellular subcompartments that vary in glutamate concentration and are preferentially sampled by different technologies.
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Affiliation(s)
- Khaled Moussawi
- Department of Neurosciences, Medical University of South Carolina Charleston, SC, USA
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Lai PC, Huang YT, Wu CC, Lai CJ, Wang PJ, Chiu TH. Ceftriaxone attenuates hypoxic-ischemic brain injury in neonatal rats. J Biomed Sci 2011; 18:69. [PMID: 21933448 PMCID: PMC3191508 DOI: 10.1186/1423-0127-18-69] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 09/21/2011] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Perinatal brain injury is the leading cause of subsequent neurological disability in both term and preterm baby. Glutamate excitotoxicity is one of the major factors involved in perinatal hypoxic-ischemic encephalopathy (HIE). Glutamate transporter GLT1, expressed mainly in mature astrocytes, is the major glutamate transporter in the brain. HIE induced excessive glutamate release which is not reuptaked by immature astrocytes may induce neuronal damage. Compounds, such as ceftriaxone, that enhance the expression of GLT1 may exert neuroprotective effect in HIE. METHODS We used a neonatal rat model of HIE by unilateral ligation of carotid artery and subsequent exposure to 8% oxygen for 2 hrs on postnatal day 7 (P7) rats. Neonatal rats were administered three dosages of an antibiotic, ceftriaxone, 48 hrs prior to experimental HIE. Neurobehavioral tests of treated rats were assessed. Brain sections from P14 rats were examined with Nissl and immunohistochemical stain, and TUNEL assay. GLT1 protein expression was evaluated by Western blot and immunohistochemistry. RESULTS Pre-treatment with 200 mg/kg ceftriaxone significantly reduced the brain injury scores and apoptotic cells in the hippocampus, restored myelination in the external capsule of P14 rats, and improved the hypoxia-ischemia induced learning and memory deficit of P23-24 rats. GLT1 expression was observed in the cortical neurons of ceftriaxone treated rats. CONCLUSION These results suggest that pre-treatment of infants at risk for HIE with ceftriaxone may reduce subsequent brain injury.
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Affiliation(s)
- Pei Chun Lai
- Institute of Pharmacology and Toxicology, Tzu Chi University, Hualien, Taiwan
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Mimura K, Tomimatsu T, Minato K, Jugder O, Kinugasa-Taniguchi Y, Kanagawa T, Nozaki M, Yanagihara I, Kimura T. Ceftriaxone Preconditioning Confers Neuroprotection in Neonatal Rats Through Glutamate Transporter 1 Upregulation. Reprod Sci 2011; 18:1193-201. [DOI: 10.1177/1933719111410710] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Kazuya Mimura
- Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
- Department of Developmental Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, Izumi, Osaka, Japan
| | - Takuji Tomimatsu
- Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Kenji Minato
- Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Otgonbaatar Jugder
- Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Yukiko Kinugasa-Taniguchi
- Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Takeshi Kanagawa
- Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Masatoshi Nozaki
- Department of Developmental Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, Izumi, Osaka, Japan
| | - Itaru Yanagihara
- Department of Developmental Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, Izumi, Osaka, Japan
| | - Tadashi Kimura
- Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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Immunohistological markers for proliferative events, gliogenesis, and neurogenesis within the adult hippocampus. Cell Tissue Res 2011; 345:1-19. [PMID: 21647561 DOI: 10.1007/s00441-011-1196-4] [Citation(s) in RCA: 237] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 05/13/2011] [Indexed: 12/29/2022]
Abstract
Biologists long believed that, once development is completed, no new neurons are produced in the forebrain. However, as is now firmly established, new neurons can be produced at least in two specific forebrain areas: the subventricular zone (SVZ) and the dentate gyrus (DG) of the hippocampal formation. Neurogenesis within the adult DG occurs constitutively throughout postnatal life, and the rate of neurogenesis within the DG can be altered under various physiological and pathophysiological conditions. The process of adult neurogenesis within the DG is a multi-step process (proliferation, differentiation, migration, targeting, and synaptic integration) that ends with the formation of a post-mitotic functionally integrated new neuron. Various markers are expressed during specific stages of adult neurogenesis. The availability of such markers allows the time-course and fate of newly born cells to be followed within the DG in a detailed and precise fashion. Several of the available markers (e.g., PCNA, Ki-67, PH3, MCM2) are markers for proliferative events, whereas others are more specific for early phases of neurogenesis and gliogenesis within the adult DG (e.g., nestin, GFAP, Sox2, Pax6). In addition, markers are available allowing events to be distinguished that are related to later steps of gliogenesis (e.g., vimentin, BLBP, S100beta) or neurogenesis (e.g., NeuroD, PSA-NCAM, DCX).
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The relative roles of diffusion and uptake in clearing synaptically released glutamate change during early postnatal development. J Neurosci 2011; 31:4743-54. [PMID: 21430173 DOI: 10.1523/jneurosci.5953-10.2011] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Glutamate uptake by transporters expressed in astrocytes combines with synaptic structure to regulate the time that synaptically released glutamate remains in the extracellular space and, consequently, the duration and location of postsynaptic receptor activation. Both factors change greatly in the rodent hippocampus during the second postnatal week when most synapses become established and begin to mature, processes that are influenced by synaptically released glutamate. Transporter expression increases, potentially speeding removal of synaptically released glutamate, whereas extracellular space decreases, thereby slowing dilution. We investigated whether these competing changes influence the glutamate concentration time course and postsynaptic responses in the CA1 region of the mouse hippocampus during this critical period of synaptic development. Our results suggest that the glutamate concentration time course remains relatively consistent over this period, although the primary mechanisms regulating glutamate clearance change. Before the second postnatal week, clearance of synaptically released glutamate depends primarily on diffusion into large extracellular spaces, whereas later in development it relies more on increased uptake capacity. Thus, increased transporter expression during this period accompanies structural changes in the neuropil, preserving a relatively consistent glutamate concentration time course and ensuring that postsynaptic receptor activation remains brief and primarily localized to receptors close to release sites.
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36
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Sasaki T, Kuga N, Namiki S, Matsuki N, Ikegaya Y. Locally Synchronized Astrocytes. Cereb Cortex 2011; 21:1889-900. [DOI: 10.1093/cercor/bhq256] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Björklund U, Persson M, Rönnbäck L, Hansson E. Primary Cultures From Cerebral Cortex and Hippocampus Enriched in Glutamatergic and GABAergic Neurons. Neurochem Res 2010; 35:1733-42. [DOI: 10.1007/s11064-010-0236-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2010] [Indexed: 12/13/2022]
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Brito VI, Rozanski VE, Beyer C, Küppers E. Dopamine regulates the expression of the glutamate transporter GLT1 but not GLAST in developing striatal astrocytes. J Mol Neurosci 2009; 39:372-9. [PMID: 19685014 DOI: 10.1007/s12031-009-9273-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 07/22/2009] [Indexed: 11/25/2022]
Abstract
Dopamine and L: -glutamate are important signals which guide the development of functional neural circuits within the striatal complex. Disequilibrium of these neurotransmitter systems is believed to be etiological for the genesis of neurological and psychiatric diseases. Since dopamine plays a crucial role for the early transmitter-regulated differentiation of striatal GABAergic neurons, we emphasized that dopaminergic transmission may also be involved in the fine tuning of intra-striatal glutamate action. In this study, we report that dopamine decreases the expression of the glutamate transporter GLT1 but not GLAST in striatal astrocytes by measuring gene and protein expression. Using glutamate-uptake approaches, we demonstrate an increase in glutamate clearance of externally added glutamate in dopamine-treated cultures compared to controls. Our findings imply that dopamine regulates the availability of L: -glutamate in the developing striatum. It is also suggested that the application of dopaminergic drugs can interfere with ontogenetic processes within the striatal complex.
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Affiliation(s)
- Veronica I Brito
- Department of Cellular Neurobiology, Eberhard-Karls University of Tübingen, Institute of Anatomy, 72074 Tübingen, Germany
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Andersson M, Blomstrand F, Hanse E. Astrocytes play a critical role in transient heterosynaptic depression in the rat hippocampal CA1 region. J Physiol 2007; 585:843-52. [PMID: 17962333 DOI: 10.1113/jphysiol.2007.142737] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Active synapses can reduce the probability of transmitter release at neighbouring synapses. Depending on whether such heterosynaptic depression is mediated by intersynaptic diffusion of transmitter or by release of gliotransmitters, astrocytes should either hinder or promote the heterosynaptic depression. In the present study we have examined the developmental profile and astrocytic involvement in a transient heterosynaptic depression (tHeSD) in the CA1 region of the rat hippocampal slice preparation. A short stimulus burst (3 impulses at 50 Hz) to one group of synapses elicited a depression of the field EPSP evoked in another group of synapses that amounted to about 25% 0.5 s after the conditioning burst. This tHeSD was associated with an increase in the paired-pulse ratio of about 30%. The tHeSD was not present in slices from rats younger than 10 postnatal days and developed towards the adult magnitude between postnatal days 10 and 20. The tHeSD was totally prevented by the glia-specific toxin fluoroacetate (FAC), by carbenoxolone, a general blocker of connexin-based channels, and by endothelin, an endogenous peptide that has been shown to block astrocytic connexin-based channels. Antagonists to GABA(B) receptors and group II/III metabotropic glutamate receptors (mGluRs) abolished the tHeSD whereas antagonists to NMDA- and adenosine A1 receptors, and to group I mGluRs, did not affect the tHeSD. These results suggest that the tHeSD relies on GABA(B) receptors, group II/III mGluRs and on gliotransmitter release from functionally mature astrocytes.
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Affiliation(s)
- My Andersson
- Institute of Neuroscience and Physiology, Göteborg University, Medicinaregatan 11, Göteborg, Sweden.
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40
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Frizzo ME, Frizzo JK, Amadio S, Rodrigues JM, Perry ML, Bernardi G, Volonté C. Extracellular adenosine triphosphate induces glutamate transporter-1 expression in hippocampus. Hippocampus 2007; 17:305-15. [PMID: 17330863 DOI: 10.1002/hipo.20269] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ATP can be significantly released following various brain insults and activates the extracellular signal-regulated protein kinase (ERK) pathway in astrocytes. Glutamate transporter-1 (GLT1) is the major forebrain astroglial glutamate transporter and its expression is stimulated also via ERK1/2 phosphorylation. We thus hypothesized that extracellular ATP could be a signal to GLT1 modulation in hippocampal slices obtained from rat. We indeed observed by western blot analysis that, after 1 mM ATP exposure, GLT1 expression, but not the glutamate-aspartate transporter, was enhanced. At the same time, high ATP induced significant rates of cell death in piramidal and granule cell layers, as shown by propidium iodide uptake, and increased glutamate uptake through GLT1 transporter. Also using confocal laser-scanning microscopy, we observed that ATP induced a vigorous and extensive GLT1-labeling on glial fibrillary acidic protein-positive cells. This stimulation was abolished by purine/pyrimidine nucleotide receptor antagonists and by MEK1/2 inhibitor. The present study demonstrates a novel mechanism of GLT1 regulation by extracellular ATP, reinforcing the evidence of cross talk between glutamatergic and purinergic systems.
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Lipski J, Wan CK, Bai JZ, Pi R, Li D, Donnelly D. Neuroprotective potential of ceftriaxone in in vitro models of stroke. Neuroscience 2007; 146:617-29. [PMID: 17363173 DOI: 10.1016/j.neuroscience.2007.02.003] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 02/01/2007] [Accepted: 02/03/2007] [Indexed: 12/01/2022]
Abstract
Astrocytic glutamate transporters are considered an important target for neuroprotective therapies as the function of these transporters is abnormal in stroke and other neurological disorders associated with excitotoxicity. Recently, Rothstein et al., [Rothstein JD, Patel S, Regan MR, Haenggeli C, Huang YH, Bergles DE, Jin L, Dykes Hoberg M, Vidensky S, Chung DS, Toan SV, Bruijn LI, Su ZZ, Gupta P, Fisher PB (2005) Beta-lactam antibiotics offer neuroprotection by increasing glutamate transporter expression. Nature 433:73-77] reported that beta-lactam antibiotics (including ceftriaxone, which easily crosses the blood-brain barrier) increase glutamate transporter 1 (GLT-1) expression and reduce cell death resulting from oxygen-glucose deprivation (OGD) in dissociated embryonic cortical cultures. To determine whether a similar neuroprotective mechanism operates in more mature neurons, which show a different pattern of response to ischemia than primary cultures, we exposed acute hippocampal slices obtained from rats treated with ceftriaxone for 5 days (200 mg/kg; i.p.) to OGD. Whole-cell patch clamp recording of glutamate-induced N-methyl-d-aspartate (NMDA) currents from CA1 pyramidal neurons showed a larger potentiation of these currents after application of 15 microM dl-threo-beta-benzyloxyaspartic acid (TBOA; a potent blocker of glutamate transporters) in ceftriaxone-injected animals than in untreated animals, indicating increased glutamate transporter activity. Western blot analysis did not reveal GLT-1 upregulation in the hippocampus. Delay to OGD-induced hypoxic spreading depression (HSD) recorded in slices obtained from ceftriaxone-treated rats was longer (6.3+/-0.2 vs. 5.2+/-0.2 min; P<0.001) than that in the control group, demonstrating a neuroprotective action of the antibiotic in this model. The effect of ceftriaxone was also tested in organotypic hippocampal slices obtained from P7-9 rats (>14 days in vitro). OGD or glutamate (3.5-5.0 mM) damaged CA1 pyramidal neurons as assessed by propidium iodide (PI) fluorescence. Similar damage was observed after pre-treatment with ceftriaxone (10-200 microM; 5 days) and ceftriaxone exposure did not result in GLT-1 upregulation as assayed by Western blot. Treatment of slice cultures with dibutyryl cAMP (100-250 microM; 5 days) increased GLT-1 expression but did not reduce cell damage induced by OGD or glutamate. Thus we confirm the neuroprotective effect of antibiotic exposure on OGD-induced injury, but suggest that this action is related to independent modulation of transporter activity rather than to the level of GLT-1 protein expression. In addition, our results indicate that the protective effects of beta-lactam antibiotics are highly dependent on the experimental model.
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Affiliation(s)
- J Lipski
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92-019, Auckland 1142, New Zealand.
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42
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Szatmari P, Paterson A, Zwaigenbaum L, Roberts W, Brian J, Liu XQ, Vincent J, Skaug J, Thompson A, Senman L, Feuk L, Qian C, Bryson S, Jones M, Marshall C, Scherer S, Vieland V, Bartlett C, Mangin LV, Goedken R, Segre A, Pericak-Vance M, Cuccaro M, Gilbert J, Wright H, Abramson R, Betancur C, Bourgeron T, Gillberg C, Leboyer M, Buxbaum J, Davis K, Hollander E, Silverman J, Hallmayer J, Lotspeich L, Sutcliffe J, Haines J, Folstein S, Piven J, Wassink T, Sheffield V, Geschwind D, Bucan M, Brown T, Cantor R, Constantino J, Gilliam C, Herbert M, Lajonchere C, Ledbetter D, Lese-Martin C, Miller J, Nelson S, Samango-Sprouse C, Spence S, State M, Tanzi R, Coon H, Dawson G, Devlin B, Estes A, Flodman P, Klei L, Mcmahon W, Minshew N, Munson J, Korvatska E, Rodier P, Schellenberg G, Smith M, Spence A, Stodgell C, Tepper PG, Wijsman E, Yu CE, Rogé B, Mantoulan C, Wittemeyer K, Poustka A, Felder B, Klauck S, Schuster C, Poustka F, Bölte S, Feineis-Matthews S, Herbrecht E, Schmötzer G, Tsiantis J, Papanikolaou K, Maestrini E, Bacchelli E, Blasi F, Carone S, Toma C, Van Engeland H, De Jonge M, Kemner C, Koop F, Langemeijer M, Hijmans C, Staal W, Baird G, Bolton P, Rutter M, Weisblatt E, Green J, Aldred C, Wilkinson JA, Pickles A, Le Couteur A, Berney T, Mcconachie H, Bailey A, Francis K, Honeyman G, Hutchinson A, Parr J, Wallace S, Monaco A, Barnby G, Kobayashi K, Lamb J, Sousa I, Sykes N, Cook E, Guter S, Leventhal B, Salt J, Lord C, Corsello C, Hus V, Weeks D, Volkmar F, Tauber M, Fombonne E, Shih A, Meyer K. Mapping autism risk loci using genetic linkage and chromosomal rearrangements. Nat Genet 2007; 39:319-28. [PMID: 17322880 PMCID: PMC4867008 DOI: 10.1038/ng1985] [Citation(s) in RCA: 972] [Impact Index Per Article: 57.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Accepted: 01/19/2007] [Indexed: 01/08/2023]
Abstract
Autism spectrum disorders (ASDs) are common, heritable neurodevelopmental conditions. The genetic architecture of ASDs is complex, requiring large samples to overcome heterogeneity. Here we broaden coverage and sample size relative to other studies of ASDs by using Affymetrix 10K SNP arrays and 1,181 [corrected] families with at least two affected individuals, performing the largest linkage scan to date while also analyzing copy number variation in these families. Linkage and copy number variation analyses implicate chromosome 11p12-p13 and neurexins, respectively, among other candidate loci. Neurexins team with previously implicated neuroligins for glutamatergic synaptogenesis, highlighting glutamate-related genes as promising candidates for contributing to ASDs.
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Affiliation(s)
- Peter Szatmari
- Department of Psychiatry and Behavioural Neurosciences
McMaster University [Hamilton, Ontario]Offord Centre for Child StudiesHamilton, Ontario, L8S 4K1, Canada
| | - Andrew Paterson
- The Centre for Applied Genomics, Toronto
University of TorontoThe Hospital for Sick ChildrenDepartment of Molecular GeneticsMcLaughlin CentreToronto, Ontario, Canada M5G 1L7
| | - Lonnie Zwaigenbaum
- Department of Pediatrics
University of Alberta [Edmonton]Edmonton, AL T6G 2J3, USA
| | - Wendy Roberts
- Autism Research Unit
University of TorontoThe Hospital for Sick ChildrenToronto, Ontario, M5G 1X8, Canada
| | - Jessica Brian
- Autism Research Unit
University of TorontoThe Hospital for Sick ChildrenToronto, Ontario, M5G 1X8, Canada
| | - Xiao-Qing Liu
- The Centre for Applied Genomics, Toronto
University of TorontoThe Hospital for Sick ChildrenDepartment of Molecular GeneticsMcLaughlin CentreToronto, Ontario, Canada M5G 1L7
| | - John Vincent
- Department of Psychiatry
University of TorontoDepartment of Psychiatry - 250 College Street 8th floor Toronto, Ontario M5T 1R8, Canada
| | - Jennifer Skaug
- The Centre for Applied Genomics, Toronto
University of TorontoThe Hospital for Sick ChildrenDepartment of Molecular GeneticsMcLaughlin CentreToronto, Ontario, Canada M5G 1L7
| | - Ann Thompson
- Department of Psychiatry and Behavioural Neurosciences
McMaster University [Hamilton, Ontario]Offord Centre for Child StudiesHamilton, Ontario, L8S 4K1, Canada
| | - Lili Senman
- Autism Research Unit
University of TorontoThe Hospital for Sick ChildrenToronto, Ontario, M5G 1X8, Canada
| | - Lars Feuk
- The Centre for Applied Genomics, Toronto
University of TorontoThe Hospital for Sick ChildrenDepartment of Molecular GeneticsMcLaughlin CentreToronto, Ontario, Canada M5G 1L7
| | - Cheng Qian
- The Centre for Applied Genomics, Toronto
University of TorontoThe Hospital for Sick ChildrenDepartment of Molecular GeneticsMcLaughlin CentreToronto, Ontario, Canada M5G 1L7
| | - Susan Bryson
- Departments of Pediatrics and Psychology
Dalhousie University [Halifax]Izaak Walton Killam Health Centre - Halifax, Canada
| | - Marshall Jones
- Department of Neural and Behavioral Sciences
Pennsylvania State University College of MedicineHershey, PA, USA
| | - Christian Marshall
- The Centre for Applied Genomics, Toronto
University of TorontoThe Hospital for Sick ChildrenDepartment of Molecular GeneticsMcLaughlin CentreToronto, Ontario, Canada M5G 1L7
| | - Stephen Scherer
- The Centre for Applied Genomics, Toronto
University of TorontoThe Hospital for Sick ChildrenDepartment of Molecular GeneticsMcLaughlin CentreToronto, Ontario, Canada M5G 1L7
- Department of Molecular Genetics [Toronto]
University of Toronto1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Veronica Vieland
- Battelle Center for Mathematical Medicine
Ohio State University [Columbus]Nationwide Children's Hospital700 Childrens Dr, Columbus, OH 43205, USA
| | - Christopher Bartlett
- Department of Pathology and Laboratory Medicine
The University of North Carolina at Chapel HillChapel Hill, North Carolina, USA
| | - La Vonne Mangin
- Battelle Center for Mathematical Medicine
Ohio State University [Columbus]Nationwide Children's Hospital700 Childrens Dr, Columbus, OH 43205, USA
| | - Rhinda Goedken
- Department of Computer Science
University of IowaIowa City, IA 52242, USA
| | - Alberto Segre
- Department of Computer Science
University of IowaIowa City, IA 52242, USA
| | - Margaret Pericak-Vance
- John P. Hussman Institute for Human Genomics
University of MiamiDr John T. Macdonald Foundation Department of Human Genetics, Miami, Florida 33136, USA
| | - Michael Cuccaro
- John P. Hussman Institute for Human Genomics
University of MiamiDr John T. Macdonald Foundation Department of Human Genetics, Miami, Florida 33136, USA
| | - John Gilbert
- John P. Hussman Institute for Human Genomics
University of MiamiDr John T. Macdonald Foundation Department of Human Genetics, Miami, Florida 33136, USA
| | - Harry Wright
- W.S. Hall Psychiatric Institute
University of South Carolina [Columbia]Columbia, South Carolina SC 29203, USA
| | - Ruth Abramson
- W.S. Hall Psychiatric Institute
University of South Carolina [Columbia]Columbia, South Carolina SC 29203, USA
| | - Catalina Betancur
- Neurobiologie et Psychiatrie
INSERM U513AP-HP, Groupe hospitalier Henri Mondor-Albert ChenevierUniversité Paris 12 - Paris-Est Créteil Val de Marne51 Avenue du Maréchal de Lattre de Tassigny, 94010 Créteil, France
| | - Thomas Bourgeron
- Génétique Humaine et Fonctions Cognitives
Institut Pasteur [Paris]Centre National de la Recherche Scientifique25-28 rue du Docteur Roux F-75724 Paris Cedex 15, France
| | - Christopher Gillberg
- Gillberg Neuropsychiatry Centre
Gothenburg UniversityVasagatan 33, 411 37 Göteborg, Sweden
- Institute of Child Health
University College of London [London]Gower St, London WC1E 6BT, UK
| | - Marion Leboyer
- IMRB, Institut Mondor de Recherche Biomédicale
INSERMIFR10Université Paris-Est Créteil Val-de-Marne - Paris 128 rue du Général Sarrail 94010 Créteil, France
| | - Joseph Buxbaum
- Friedman Brain Institute, Mount Sinai
Icahn School of Medicine at Mount Sinai [New York]New York 10029, USA
- Department of Neuroscience
Icahn School of Medicine at Mount Sinai [New York]1428 Madison Ave, New York, NY 10029, USA
| | - Kenneth Davis
- Friedman Brain Institute, Mount Sinai
Icahn School of Medicine at Mount Sinai [New York]New York 10029, USA
- Department of Meteorology
Pennsylvania State University503 Walker Building University Park, PA 16802-5013, USA
| | - Eric Hollander
- Friedman Brain Institute, Mount Sinai
Icahn School of Medicine at Mount Sinai [New York]New York 10029, USA
| | - Jeremy Silverman
- Friedman Brain Institute, Mount Sinai
Icahn School of Medicine at Mount Sinai [New York]New York 10029, USA
- Department of Psychiatry [Pittsburgh]
University of Pittsburgh School of Medicine [Pittsburgh]Thomas Detre Hall of the Western Psychiatric Institute and Clinic, University of Pittsburgh, 3811 O'Hara Street, Pittsburgh, PA 15213
| | - Joachim Hallmayer
- Stanford University School of Medicine [Stanford]
Stanford University [Stanford]291 Campus Drive Rm LK3C02 Li Ka Shing Building, 3rd floor Dean's Office, MC 5216 Stanford, CA 94305-5101
| | - Linda Lotspeich
- Department of Psychiatry
Stanford University School of MedicineDivision of Child and Adolescent Psychiatry and Child Development, Stanford, CA 94304,
| | - James Sutcliffe
- Vanderbilt Brain Institute
Vanderbilt University Medical CentreCenter for Human Genetics Research - Nashville, Tennessee 37232
- Department of Molecular Physiology & Biophysics and Psychiatry
Vanderbilt University of NashvilleCenters for Human Genetics Research and Molecular NeuroscienceNashville, Tennessee 37232
| | - Jonathan Haines
- Vanderbilt Brain Institute
Vanderbilt University Medical CentreCenter for Human Genetics Research - Nashville, Tennessee 37232
| | - Susan Folstein
- John P. Hussman Institute for Human Genomics
University of MiamiDr John T. Macdonald Foundation Department of Human Genetics, Miami, Florida 33136, USA
- Department of Psychiatry
Johns Hopkins UniversityBaltimore, MD
| | - Joseph Piven
- Carolina Institute for Developmental Disabilities
The University of North Carolina at Chapel HillUniversity of North Carolina Chapel Hill Campus Box # 7255 Chapel Hill, N.C. 27599-3366
| | - Thomas Wassink
- Department of Psychiatry
Carver College of MedicineIowa City, Iowa 52242
| | - Val Sheffield
- Department of Pediatrics
Howard Hughes MedicalInstitute Carver College of MedicineUniversity of IowaIowa City, Iowa 52242
| | - Daniel Geschwind
- Department of Neurology
UCLA School of MedicineLos Angeles, California
| | - Maja Bucan
- Department of Genetics
University of PennsylvaniaSchool of Medicine3451 Walnut St, Philadelphia, PA 19104
| | - Ted Brown
- N.Y.S. Institute for Basic Research in Developmental Disabilities
N.Y.S. Institute for Basic Research in Developmental DisabilitiesStaten Island, NY
| | - Rita Cantor
- Department of Human Genetics, UCLA
University of California at Los Angeles [Los Angeles]Semel InstituteDavid Geffen School of Medicine, CA 90095
| | - John Constantino
- Department of Psychiatry
Washington university in St. LouisSchool of Medicine, St. Louis, Missouri 63130
| | - Conrad Gilliam
- University of Chicago
Edward H. Levi Hall 5801 South Ellis Avenue Chicago, Illinois 60637
| | - Martha Herbert
- Harvard Medical School
Massachusetts General Hospital [Boston]Boston, MA
| | - Clara Lajonchere
- Autism Genetic Resource Exchange
Autism SpeaksLos Angeles, California 90036-4234
| | - David Ledbetter
- Department of Genetics
Emory University [Atlanta, GA]Atlanta, GA
- Developmental Brain and Behaviour Unit
University of Southampton [Southampton]School of Psychology - University Rd, Southampton SO17 1BJ
| | | | | | - Stan Nelson
- Institute of Human Genetics
Bonn Universität [Bonn]Regina-Pacis-Weg 3, 53113 Bonn
| | - Carol Samango-Sprouse
- Children's National Medical Center
George Washington UniversitySchool of Medicine - 2121 I St NW, Washington, DC 20052
| | - Sarah Spence
- Department of Human Genetics, UCLA
University of California at Los Angeles [Los Angeles]Semel InstituteDavid Geffen School of Medicine, CA 90095
| | - Matthew State
- Institute of Human Genetics
Bonn Universität [Bonn]Regina-Pacis-Weg 3, 53113 Bonn
| | - Rudolph Tanzi
- Massachusetts General Hospital
Massachusetts General HospitalBoston, MA
| | - Hilary Coon
- Department of Developmental Neuroscience
IRCCS Fondazione Stella Maris PisaViale del Tirreno 331 - 56128, Calambrone, Pisa
| | - Geraldine Dawson
- Autism Speaks and the Department of Psychiatry
The University of North Carolina at Chapel HillChapel Hill, North Carolina
| | - Bernie Devlin
- Department of Psychiatry [Pittsburgh]
University of Pittsburgh School of Medicine [Pittsburgh]Thomas Detre Hall of the Western Psychiatric Institute and Clinic, University of Pittsburgh, 3811 O'Hara Street, Pittsburgh, PA 15213
| | - Annette Estes
- Department of Speech and Hearing Sciences
University of Washington [Seattle]Seattle, Washington 98195
| | - Pamela Flodman
- Department of Pediatrics
University of California, Irvine [Irvine]Irvine, CA 92697
| | - Lambertus Klei
- Department of Psychiatry [Pittsburgh]
University of Pittsburgh School of Medicine [Pittsburgh]Thomas Detre Hall of the Western Psychiatric Institute and Clinic, University of Pittsburgh, 3811 O'Hara Street, Pittsburgh, PA 15213
| | - William Mcmahon
- Department of Developmental Neuroscience
IRCCS Fondazione Stella Maris PisaViale del Tirreno 331 - 56128, Calambrone, Pisa
| | - Nancy Minshew
- Department of Psychiatry [Pittsburgh]
University of Pittsburgh School of Medicine [Pittsburgh]Thomas Detre Hall of the Western Psychiatric Institute and Clinic, University of Pittsburgh, 3811 O'Hara Street, Pittsburgh, PA 15213
| | - Jeff Munson
- Department of Psychiatry and Behavioral Sciences
University of Washington [Seattle]Seattle, WA 98195
| | - Elena Korvatska
- Department of Pediatrics
University of California, Irvine [Irvine]Irvine, CA 92697
| | - Patricia Rodier
- Department of OB/GYN
University of Rochester Medical Center601 Elmwood Ave, Rochester, NY 14642
| | - Gerard Schellenberg
- Pathology and Laboratory Medicine
University of PennsylvaniaPennsylvania 19104
| | - Moyra Smith
- Department of Pediatrics
University of California, Irvine [Irvine]Irvine, CA 92697
| | - Anne Spence
- Department of Pediatrics
University of California, Irvine [Irvine]Irvine, CA 92697
| | - Chris Stodgell
- Department of OB/GYN
University of Rochester Medical Center601 Elmwood Ave, Rochester, NY 14642
| | - Ping Guo Tepper
- Department of Epidemiology
University of Pittsburgh4200 Fifth Ave, Pittsburgh, PA 15260
| | - Ellen Wijsman
- Departments of Biostatistics and Medicine
University of Washington [Seattle]Seattle, Washington 98195
| | - Chang-En Yu
- Department of Medicine
University of Washington [Seattle]Seattle, WA
| | - Bernadette Rogé
- Octogone, Octogone Unité de Recherche Interdisciplinaire
Université Toulouse 2Université Toulouse - Jean Jaurès (campus Mirail)Maison de la Recherche 5, Allées A. Machado 31058 Toulouse Cedex 9
| | - Carine Mantoulan
- Centre de Référence du Syndrome de Prader-Willi
CHU Toulouse [Toulouse]Service d'endocrinologie, génétique, gynécologie et maladies de l'os, Toulouse
| | - Kerstin Wittemeyer
- Department of Psychiatry
University of Oxford [Oxford]Warneford HospitalHeadington, Oxford, OX3 7JX
| | - Annemarie Poustka
- Division of Molecular Genome Analysis
German Cancer Research CenterIm Neuenheimer Feld 280, 69121 Heidelberg
| | - Bärbel Felder
- Division of Molecular Genome Analysis
German Cancer Research CenterIm Neuenheimer Feld 280, 69121 Heidelberg
| | - Sabine Klauck
- Division of Molecular Genome Analysis
German Cancer Research CenterIm Neuenheimer Feld 280, 69121 Heidelberg
| | - Claudia Schuster
- Division of Molecular Genome Analysis
German Cancer Research CenterIm Neuenheimer Feld 280, 69121 Heidelberg
| | - Fritz Poustka
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy
Goethe-Universität Frankfurt am MainSenckenberganlage 31 - 60325 Frankfurt am Main
| | - Sven Bölte
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy
Goethe-Universität Frankfurt am MainSenckenberganlage 31 - 60325 Frankfurt am Main
| | - Sabine Feineis-Matthews
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy
Goethe-Universität Frankfurt am MainSenckenberganlage 31 - 60325 Frankfurt am Main
| | - Evelyn Herbrecht
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy
Goethe-Universität Frankfurt am MainSenckenberganlage 31 - 60325 Frankfurt am Main
| | - Gabi Schmötzer
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy
Goethe-Universität Frankfurt am MainSenckenberganlage 31 - 60325 Frankfurt am Main
| | - John Tsiantis
- University Department of Child Psychiatry
Athens UniversityMedical School, Agia Sophia Children's Hospital, 115 27 Athens
| | - Katerina Papanikolaou
- University Department of Child Psychiatry
Athens UniversityMedical School, Agia Sophia Children's Hospital, 115 27 Athens
| | - Elena Maestrini
- Department of Pharmacy and Biotechnology
Università di Bologna [Bologna]Via Zamboni, 33, 40126 Bologna
| | - Elena Bacchelli
- Department of Pharmacy and Biotechnology
Università di Bologna [Bologna]Via Zamboni, 33, 40126 Bologna
| | - Francesca Blasi
- Department of Pharmacy and Biotechnology
Università di Bologna [Bologna]Via Zamboni, 33, 40126 Bologna
| | - Simona Carone
- Medical Genetics Laboratory
Policlinico S. Orsola-MalpighiVia Pietro Albertoni, 15, 40138 Bologna
| | - Claudio Toma
- Department of Pharmacy and Biotechnology
Università di Bologna [Bologna]Via Zamboni, 33, 40126 Bologna
| | - Herman Van Engeland
- Department of Psychiatry
University Medical Center UtrechtBrain Center Rudolf MagnusHeidelberglaan 100, 3584 CX Utrecht
| | - Maretha De Jonge
- Department of Psychiatry
University Medical Center UtrechtBrain Center Rudolf MagnusHeidelberglaan 100, 3584 CX Utrecht
| | - Chantal Kemner
- Department of Neurocognition
Maastricht University [Maastricht]Faculty of Psychology - Minderbroedersberg 4, 6211 LK Maastricht
| | - Frederieke Koop
- Department of Psychiatry
University Medical Center UtrechtBrain Center Rudolf MagnusHeidelberglaan 100, 3584 CX Utrecht
| | - Marjolein Langemeijer
- Department of Psychiatry
University Medical Center UtrechtBrain Center Rudolf MagnusHeidelberglaan 100, 3584 CX Utrecht
| | - Channa Hijmans
- Department of Psychiatry
University Medical Center UtrechtBrain Center Rudolf MagnusHeidelberglaan 100, 3584 CX Utrecht
| | - Wouter Staal
- Department of Psychiatry
University Medical Center UtrechtBrain Center Rudolf MagnusHeidelberglaan 100, 3584 CX Utrecht
| | - Gillian Baird
- Newcomen Centre
Guy's Hospital [London]London, SE1 9RT
| | - Patrick Bolton
- Department of Child and Adolescent Psychiatry
Institute of psychiatryLondon, SE5 8AF
| | - Michael Rutter
- SGDP, MRC Social, Genetic and Developmental Psychiatry Centre
The Institute of PsychiatryKing's College LondonStrand, London WC2R 2LS
| | - Emma Weisblatt
- University of Cambridge Clinical School
University of CambridgeCambridge
| | - Jonathan Green
- Manchester Academic Health Sciences Centre
Manchester Academic Health Sciences CentreManchester M13 9NT
| | - Catherine Aldred
- Manchester Academic Health Sciences Centre
Manchester Academic Health Sciences CentreManchester M13 9NT
| | - Julie-Anne Wilkinson
- Manchester Academic Health Sciences Centre
Manchester Academic Health Sciences CentreManchester M13 9NT
| | - Andrew Pickles
- Department of Medicine, Manchester
The University of Manchester [Manchester]School of Epidemiology and Health ScienceManchester M13 9PT
| | - Ann Le Couteur
- Department of Child and Adolescent Psychiatry
Newcastle University [Newcastle]Institute of Health & Society (Child & Adolescent Psychiatry)3rd Floor - Sir James Spence Institute - Royal Victoria Infirmary - Queen Victoria Road - Newcastle upon Tyne NE1 4LP
| | - Tom Berney
- Department of Child and Adolescent Psychiatry
Newcastle University [Newcastle]Institute of Health & Society (Child & Adolescent Psychiatry)3rd Floor - Sir James Spence Institute - Royal Victoria Infirmary - Queen Victoria Road - Newcastle upon Tyne NE1 4LP
| | - Helen Mcconachie
- Child and Adolescent Mental Health
Newcastle University [Newcastle]Sir James Spence Institute, Newcastle upon Tyne, NE1 4LP
| | - Anthony Bailey
- Department of Psychiatry
University of Oxford [Oxford]Warneford HospitalHeadington, Oxford, OX3 7JX
| | - Kostas Francis
- Department of Psychiatry
University of Oxford [Oxford]Warneford HospitalHeadington, Oxford, OX3 7JX
| | - Gemma Honeyman
- Department of Psychiatry
University of Oxford [Oxford]Warneford HospitalHeadington, Oxford, OX3 7JX
| | - Aislinn Hutchinson
- Department of Psychiatry
University of Oxford [Oxford]Warneford HospitalHeadington, Oxford, OX3 7JX
| | - Jeremy Parr
- Department of Psychiatry
University of Oxford [Oxford]Warneford HospitalHeadington, Oxford, OX3 7JX
- Institutes of Neuroscience and Health and Society
Newcastle University [Newcastle]Newcastle Upon Tyne, NE1 7RU
| | - Simon Wallace
- Department of Psychiatry
University of Oxford [Oxford]Warneford HospitalHeadington, Oxford, OX3 7JX
| | - Anthony Monaco
- Wellcome Trust Centre for Human Genetics
University of Oxford [Oxford]Roosevelt Drive - Headington, Oxford OX3 7BN
| | - Gabrielle Barnby
- Wellcome Trust Centre for Human Genetics
University of Oxford [Oxford]Roosevelt Drive - Headington, Oxford OX3 7BN
| | - Kazuhiro Kobayashi
- Wellcome Trust Centre for Human Genetics
University of Oxford [Oxford]Roosevelt Drive - Headington, Oxford OX3 7BN
| | - Janine Lamb
- Wellcome Trust Centre for Human Genetics
University of Oxford [Oxford]Roosevelt Drive - Headington, Oxford OX3 7BN
- Centre for Integrated Genomic Medical Research, Manchester
The University of Manchester [Manchester]Manchester, M13 9PT
| | - Ines Sousa
- Wellcome Trust Centre for Human Genetics
University of Oxford [Oxford]Roosevelt Drive - Headington, Oxford OX3 7BN
| | - Nuala Sykes
- Wellcome Trust Centre for Human Genetics
University of Oxford [Oxford]Roosevelt Drive - Headington, Oxford OX3 7BN
| | - Edwin Cook
- Department of Psychiatry
Institute for Juvenile ResearchUniversity of Illinois at Chicago2035 W Taylor St, Chicago, IL 60612
- Institute for Juvenile Research
University of Illinois at ChicagoDepartment of Psychiatry - 2035 W Taylor St, Chicago, IL 60612
| | - Stephen Guter
- Department of Psychiatry
Institute for Juvenile ResearchUniversity of Illinois at Chicago2035 W Taylor St, Chicago, IL 60612
- Department of Disability and Human Development
University of Illinois at ChicagoChicago, IL 60608
| | - Bennett Leventhal
- Department of Psychiatry
Institute for Juvenile ResearchUniversity of Illinois at Chicago2035 W Taylor St, Chicago, IL 60612
- Department of Child and Adolescent Psychiatry
New York University [New York]NYU Child Study Center - 70 Washington Square S, New York, NY 10012
| | - Jeff Salt
- Department of Psychiatry [Pittsburgh]
University of Pittsburgh School of Medicine [Pittsburgh]Thomas Detre Hall of the Western Psychiatric Institute and Clinic, University of Pittsburgh, 3811 O'Hara Street, Pittsburgh, PA 15213
| | - Catherine Lord
- Autism and Communicative Disorders Centre
University of MichiganAnn Arbor, Michigan
| | - Christina Corsello
- Autism and Communicative Disorders Centre
University of MichiganAnn Arbor, Michigan
| | - Vanessa Hus
- Autism and Communicative Disorders Centre
University of MichiganAnn Arbor, Michigan
| | - Daniel Weeks
- Human Genetics Department
University of Pittsburgh4200 Fifth Ave, Pittsburgh, PA 15260
- SFU-DMG, SFU Discrete Mathematics Group
Simon Fraser UniversityDept. Mathematics, SFU 8888 University Drive Burnaby, BC, V5A 1S6
| | - Fred Volkmar
- Child Study Centre
Yale University School of MedicineNew Haven, Connecticut 0652
| | - Maïté Tauber
- Centre d'Endocrinologie, Maladies Osseuses, Génétique et Gynécologie Médicale
CHU Toulouse [Toulouse]Hôpital des Enfants330, avenue de Grande-Bretagne - TSA 70034 - 31059 Toulouse cedex 9
| | - Eric Fombonne
- Department of Child Psychiatry
McGill University [Montreal]Montreal Children's Hospital2300 rue Tupper, Montreal, H3H 1P3
| | - Andy Shih
- Scientific Affairs
Autism Speaks2 Park Avenue, 11th Floor, New York, NY 10016
| | - Kacie Meyer
- University of Iowa [Iowa]
University of IowaIowa City, IA 52242
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Lauriat TL, Schmeidler J, McInnes LA. Early rapid rise in EAAT2 expression follows the period of maximal seizure susceptibility in human brain. Neurosci Lett 2007; 412:89-94. [PMID: 17127000 DOI: 10.1016/j.neulet.2006.10.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 10/19/2006] [Accepted: 10/24/2006] [Indexed: 11/23/2022]
Abstract
Seizures are relatively common in the first weeks of life and can have lasting effects on brain development due to glutamate excitotoxicity. The excitatory amino acid transporter 2 (EAAT2) is responsible for the majority of glutamate uptake in the brain and mice with this gene deleted die from seizures. Therefore, we reasoned that developmental changes in the expression of EAAT2 might correlate with the period of increased susceptibility to seizures in humans, reflecting a changing vulnerability to excitotoxic insults. Expression levels of eight splice forms of EAAT2 were measured using quantitative RT-PCR from human prefrontal cortex and hippocampus at 1-2 months, 1-2 years, 8 years, 15-16 years, and 18-22 years of age. There was a significant increase in expression of most isoforms between 1-2 months and 1-2 years with isoform-specific patterns after that period. The increase in EAAT2 expression during the first 2 years of life corresponds to a period of maximal synapse formation and other changes in the glutamatergic system such as increased NMDA receptor expression. Moreover, the low expression of EAAT2 in the first months of life corresponds to the period of maximum susceptibility to seizures.
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Affiliation(s)
- Tara L Lauriat
- Department of Psychiatry, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA
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Le Meur K, Galante M, Angulo MC, Audinat E. Tonic activation of NMDA receptors by ambient glutamate of non-synaptic origin in the rat hippocampus. J Physiol 2006; 580:373-83. [PMID: 17185337 PMCID: PMC2075557 DOI: 10.1113/jphysiol.2006.123570] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In several neuronal types of the CNS, glutamate and GABA receptors mediate a persistent current which reflects the presence of a low concentration of transmitters in the extracellular space. Here, we further characterize the tonic current mediated by ambient glutamate in rat hippocampal slices. A tonic current of small amplitude (53.99 +/- 6.48 pA at +40 mV) with the voltage dependency and the pharmacology of NMDA receptors (NMDARs) was detected in virtually all pyramidal cells of the CA1 and subiculum areas. Manipulations aiming at increasing D-serine or glycine extracellular concentrations failed to modify this current indicating that the glycine binding sites of the NMDARs mediating the tonic current were saturated. In contrast, non-transportable inhibitors of glutamate transporters increased the amplitude of this tonic current, indicating that the extracellular concentration of glutamate primarily regulates its magnitude. Neither AMPA/kainate receptors nor metabotropic glutamate receptors contributed significantly to this tonic excitation of pyramidal neurons. In the presence of glutamate transporter inhibitors, however, a significant proportion of the tonic conductance was mediated by AMPA receptors. The tonic current was unaffected when inhibiting vesicular release of transmitters from neurons but was increased upon inhibition of the enzyme converting glutamate in glutamine in glial cells. These observations indicate that ambient glutamate is mainly of glial origin. Finally, experiments with the use-dependent antagonist MK801 indicated that NMDARs mediating the tonic conductance are probably extra-synaptic NMDARs.
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Affiliation(s)
- Karim Le Meur
- Inserm U603, Université Paris Descartes, 45 rue des Saints Pères, 75006 Paris, France
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Imasawa M, Kashiwagi K, Iizuka Y, Tanaka M, Tsukahara S. Different expression role among glutamate transporters in rat retinal glial cells under various culture conditions. ACTA ACUST UNITED AC 2005; 142:1-8. [PMID: 16269203 DOI: 10.1016/j.molbrainres.2005.08.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Revised: 04/25/2005] [Accepted: 08/16/2005] [Indexed: 11/26/2022]
Abstract
Using cultured rat retinal glial cells, the changes in the expression of glutamate transporters (GLTs) under such conditions as the degree of confluence of the cells, hypoxia, glutamate loading, and potassium loading, were assessed. After the retinal glial cells were isolated from 3-day-old Sprague-Dawley rats, GLAST, GLT-1, and EAAC1 mRNA expression was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and their protein expression was confirmed by Western blot analysis and immunostaining. Changes in the expression of the GLTs at 6 h after passage and at confluence, during culture in 5% oxygen, during glutamate loading and during potassium loading were assessed using real-time PCR. Although the GLAST mRNA expression was increased during glutamate and potassium loading, no changes in the expression were observed during hypoxia and at confluence. By contrast, the GLT-1 mRNA expression was increased during hypoxia and at confluence, but not during glutamate and potassium loading, and the EAAC1 mRNA expression was not changed only during glutamate loading. The expression of EAAC1 in the cultured retinal glial cells was confirmed. The expression of the GLTs varied according to the environment and the type of load suggests that the involvement of the GLTs in retinal physiology and pathology varies depending on the subtype.
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Affiliation(s)
- Mitsuhiro Imasawa
- Department of Ophthalmology, University of Yamanashi Medical Faculty of Medicine, 1110 Shimokato, Tamaho, Yamanashi 409-3898, Japan
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46
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Renden R, Taschenberger H, Puente N, Rusakov DA, Duvoisin R, Wang LY, Lehre KP, von Gersdorff H. Glutamate transporter studies reveal the pruning of metabotropic glutamate receptors and absence of AMPA receptor desensitization at mature calyx of Held synapses. J Neurosci 2005; 25:8482-97. [PMID: 16162930 PMCID: PMC3375655 DOI: 10.1523/jneurosci.1848-05.2005] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2005] [Revised: 06/29/2005] [Accepted: 07/21/2005] [Indexed: 11/21/2022] Open
Abstract
We examined the effect of glutamate transporter blockade at the calyx of Held synapse. In immature synapses [defined as postnatal day 8 (P8) to P10 rats], transporter blockade causes tonic activation of NMDA receptors and strong inhibition of the AMPA receptor-mediated EPSC amplitude. EPSC inhibition was blocked with a metabotropic glutamate receptor (mGluR) antagonist [1 microm LY341495 (2S-2-amino-2-(1S,2S-2-carboxycycloprop-1-yl)-3-(xanth-9-yl)propanoic acid)], suggesting that elevated resting glutamate concentration specifically activates group II and group III mGluRs. Using mGluR subtype-specific agonists and antagonists, we determined that increased glutamate activates presynaptic mGluR2/3 and mGluR8 receptors but not mGluR4, although this receptor is present. Surprisingly, in older animals (P16-P18), transporter blockade had no effect on EPSC amplitude because of a developmental downregulation of group II/III mGluR activation in rats and mice. In contrast to other CNS synapses, we observed no effect of transporter blockade on EPSC decay kinetics, although expression of glutamate transporters was strong in nearby glial processes at both P9 and P17. Finally, using a low-affinity AMPA receptor antagonist (gamma-D-glutamylglycine), we show that desensitization occurs at P8-P10 but is absent at P16-P18, even during trains of high-frequency (100-300 Hz) stimulation. We suggest that diffusion and transporter activation are insufficient to clear synaptically released glutamate at immature calyces, resulting in significant desensitization. Thus, mGluRs may be expressed in the immature calyx to help limit glutamate release. In the more mature calyx, there is a far smaller diffusional barrier attributable to the highly fenestrated synaptic terminal morphology, so AMPA receptor desensitization is avoided and mGluR-mediated inhibition is not necessary.
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Affiliation(s)
- Robert Renden
- The Vollum Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
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