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Krishnan KS, Billups B. ASC Transporters Mediate D-Serine Transport into Astrocytes Adjacent to Synapses in the Mouse Brain. Biomolecules 2023; 13:biom13050819. [PMID: 37238689 DOI: 10.3390/biom13050819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
D-serine is an important signalling molecule, which activates N-methyl D-aspartate receptors (NMDARs) in conjunction with its fellow co-agonist, the neurotransmitter glutamate. Despite its involvement in plasticity and memory related to excitatory synapses, its cellular source and sink remain a question. We hypothesise that astrocytes, a type of glial cell that surrounds synapses, are likely candidates to control the extracellular concentration of D-Serine by removing it from the synaptic space. Using in situ patch clamp recordings and pharmacological manipulation of astrocytes in the CA1 region of the mouse hippocampal brain slices, we investigated the transport of D-serine across the plasma membrane. We observed the D-serine-induced transport-associated currents upon puff-application of 10 mM D-serine on astrocytes. Further, O-benzyl-L-serine and trans-4-hydroxy-proline, known substrate inhibitors of the alanine serine cysteine transporters (ASCT), reduced D-serine uptake. These results indicate that ASCT is a central mediator of astrocytic D-serine transport and plays a role in regulating its synaptic concentration by sequestration into astrocytes. Similar results were observed in astrocytes of the somatosensory cortex and Bergmann glia in the cerebellum, indicative of a general mechanism expressed across a range of brain areas. This removal of synaptic D-serine and its subsequent metabolic degradation are expected to reduce its extracellular availability, influencing NMDAR activation and NMDAR-dependent synaptic plasticity.
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Affiliation(s)
- Karthik Subramanian Krishnan
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Canberra, ACT 2601, Australia
| | - Brian Billups
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, 131 Garran Road, Canberra, ACT 2601, Australia
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Jersin RÅ, Jonassen LR, Dankel SN. The neutral amino acid transporter SLC7A10 in adipose tissue, obesity and insulin resistance. Front Cell Dev Biol 2022; 10:974338. [PMID: 36172277 PMCID: PMC9512047 DOI: 10.3389/fcell.2022.974338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 08/26/2022] [Indexed: 12/02/2022] Open
Abstract
Obesity, insulin resistance and type 2 diabetes represent major global health challenges, and a better mechanistic understanding of the altered metabolism in these conditions may give improved treatment strategies. SLC7A10, a member of the SLC7 subfamily of solute carriers, also named ASC-1 (alanine, serine, cysteine transporter-1), has recently been implicated as an important modulator of core processes in energy- and lipid metabolism, through its particularly high expression in adipocytes. In human cohorts, adipose SLC7A10 mRNA shows strong inverse correlations with insulin resistance, adipocyte size and components of the metabolic syndrome, strong heritability, and an association with type 2 diabetes risk alleles. SLC7A10 has been proposed as a marker of white as opposed to thermogenic beige and brown adipocytes, supported by increased formation of thermogenic beige adipocytes upon loss of Slc7a10 in mouse white preadipocytes. Overexpression of SLC7A10 in mature white adipocytes was found to lower the generation of reactive oxygen species (ROS) and stimulate mitochondrial respiratory capacity, while SLC7A10 inhibition had the opposite effect, indicating that SLC7A10 supports a beneficial increase in mitochondrial activity in white adipocytes. Consistent with these beneficial effects, inhibition of SLC7A10 was in mouse and human white adipocyte cultures found to increase lipid accumulation, likely explained by lowered serine uptake and glutathione production. Additionally, zebrafish with partial global Slc7a10b loss-of-function were found to have greater diet-induced body weight and larger visceral adipocytes compared to controls. However, challenging that SLC7A10 exerts metabolic benefits only in white adipocytes, suppression of SLC7A10 has been reported to decrease mitochondrial respiration and expression of thermogenic genes also in some beige and brown adipocyte cultures. Taken together, the data point to an important but complex role of SLC7A10 in metabolic regulation across different adipose tissue depots and adipocyte subtypes. Further research into SLC7A10 functions in specific adipocyte subtypes may lead to new precision therapeutics for mitigating the risk of insulin resistance and type 2 diabetes.
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Affiliation(s)
- Regine Åsen Jersin
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Laura Roxana Jonassen
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Simon Nitter Dankel
- Hormone Laboratory, Haukeland University Hospital, Bergen, Norway
- Mohn Nutrition Research Laboratory, Department of Clinical Science, University of Bergen, Bergen, Norway
- *Correspondence: Simon Nitter Dankel,
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Errasti-Murugarren E, Palacín M. Heteromeric Amino Acid Transporters in Brain: from Physiology to Pathology. Neurochem Res 2021; 47:23-36. [PMID: 33606172 DOI: 10.1007/s11064-021-03261-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 01/27/2021] [Accepted: 01/30/2021] [Indexed: 12/12/2022]
Abstract
In humans, more than 50 transporters are responsible for the traffic and balance of amino acids within and between cells and tissues, and half of them have been associated with disease [1]. Covering all common amino acids, Heteromeric Amino acid Transporters (HATs) are one class of such transporters. This review first highlights structural and functional studies that solved the atomic structure of HATs and revealed molecular clues on substrate interaction. Moreover, this review focuses on HATs that have a role in the central nervous system (CNS) and that are related to neurological diseases, including: (i) LAT1/CD98hc and its role in the uptake of branched chain amino acids trough the blood brain barrier and autism. (ii) LAT2/CD98hc and its potential role in the transport of glutamine between plasma and cerebrospinal fluid. (iii) y+LAT2/CD98hc that is emerging as a key player in hepatic encephalopathy. xCT/CD98hc as a potential therapeutic target in glioblastoma, and (iv) Asc-1/CD98hc as a potential therapeutic target in pathologies with alterations in NMDA glutamate receptors.
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Affiliation(s)
- Ekaitz Errasti-Murugarren
- Institute for Research in Biomedicine. Institute of Science and Technology (BIST), 08028, Barcelona, Spain. .,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 08028, Barcelona, Spain.
| | - Manuel Palacín
- Institute for Research in Biomedicine. Institute of Science and Technology (BIST), 08028, Barcelona, Spain. .,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 08028, Barcelona, Spain. .,Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, 08028, Barcelona, Spain.
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Comparative Pro-cognitive and Neurochemical Profiles of Glycine Modulatory Site Agonists and Glycine Reuptake Inhibitors in the Rat: Potential Relevance to Cognitive Dysfunction and Its Management. Mol Neurobiol 2020; 57:2144-2166. [PMID: 31960362 PMCID: PMC7170834 DOI: 10.1007/s12035-020-01875-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 01/09/2020] [Indexed: 12/30/2022]
Abstract
Frontocortical NMDA receptors are pivotal in regulating cognition and mood, are hypofunctional in schizophrenia, and may contribute to autistic spectrum disorders. Despite extensive interest in agents potentiating activity at the co-agonist glycine modulatory site, few comparative functional studies exist. This study systematically compared the actions of the glycine reuptake inhibitors, sarcosine (40–200 mg/kg) and ORG24598 (0.63–5 mg/kg), the agonists, glycine (40–800 mg/kg), and D-serine (10–160 mg/kg) and the partial agonists, S18841 (2.5 mg/kg s.c.) and D-cycloserine (2.5–40 mg/kg) that all dose-dependently prevented scopolamine disruption of social recognition in adult rats. Over similar dose ranges, they also prevented a delay-induced impairment of novel object recognition (NOR). Glycine reuptake inhibitors specifically elevated glycine but not D-serine levels in rat prefrontal cortical (PFC) microdialysates, while glycine and D-serine markedly increased levels of glycine and D-serine, respectively. D-Cycloserine slightly elevated D-serine levels. Conversely, S18841 exerted no influence on glycine, D-serine, other amino acids, monamines, or acetylcholine. Reversal of NOR deficits by systemic S18841 was prevented by the NMDA receptor antagonist, CPP (20 mg/kg), and the glycine modulatory site antagonist, L701,324 (10 mg/kg). S18841 blocked deficits in NOR following microinjection into the PFC (2.5–10 μg/side) but not the striatum. Finally, in rats socially isolated from weaning (a neurodevelopmental model of schizophrenia), S18841 (2.5 and 10 mg/kg s.c.) reversed impairment of NOR and contextual fear-motivated learning without altering isolation-induced hyperactivity. In conclusion, despite contrasting neurochemical profiles, partial glycine site agonists and glycine reuptake inhibitors exhibit comparable pro-cognitive effects in rats of potential relevance to treatment of schizophrenia and other brain disorders where cognitive performance is impaired.
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Succinimidyl (3-[(benzyloxy)carbonyl]-5-oxo-1,3-oxazolidin-4-yl)acetate on a triazole-bonded phase for the separation of dl-amino-acid enantiomers and the mass-spectrometric determination of chiral amino acids in rat plasma. J Chromatogr A 2019; 1585:131-137. [DOI: 10.1016/j.chroma.2018.11.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 10/18/2018] [Accepted: 11/22/2018] [Indexed: 12/23/2022]
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Chou IC, Mong MC, Lin CL, Yin MC. Greater Protective Potent of s-Methyl Cysteine and Syringic Acid Combination for NGF-differentiated PC12 Cells against Kainic acid-induced Injury. Int J Med Sci 2019; 16:1180-1187. [PMID: 31523181 PMCID: PMC6743275 DOI: 10.7150/ijms.35083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 07/16/2019] [Indexed: 02/07/2023] Open
Abstract
Objective: The effects of pre-treatments from s-methyl cysteine (SMC) alone, syringic acid (SA) alone and SMC plus SA against kainic acid (KA) induced injury in nerve growth factor (NGF) differentiated PC12 cells were investigated. Methods: NGF-differentiated PC12 cells were treated with 1 μM SMC, 1 μM SA or 0.5 μM SMC plus 0.5 μM SA for 2 days. Subsequently, cells were further treated by 150 μM KA. Results: KA suppressed Bcl-2 mRNA expression, enhanced Bax mRNA expression and casued cell death. SMC was greater than SA, and similar as SMC+SA in increasing Bcl-2 mRNA expression. SMC+SA led to greater increase in mitochondrial membrane potential and cell survival than SMC or SA alone. SMC+SA resulted in more reduction in reactive oxygen species and tumor necrosis factor-alpha generation, more increase in glutathione content and glutathione reductase activity than SMC or SA alone. KA up-regulated protein expression of nuclear factor kappa B (NF-κB) p65 and phosphorylated p38 (p-p38). SMC or SA pre-treatments alone limited protein expression of both factors. SMC+SA resulted in more suppression in NF-κB p65 and p-p38 expression. KA decreased glutamine level, increased glutamate level and stimulated calcium release. SMC pre-treatments alone reversed these alterations. SMC alone elevated glutamine synthetase (GS) activity and mRNA expression. SMC+SA led to greater GS activity and mRNA expression than SMC pre-treatments alone. Conclusion: These findings suggested that this combination, SMC+SA, might provide greater protective potent for neuronal cells.
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Affiliation(s)
- I-Ching Chou
- Division of Pediatric Neurology, China Medical University Hospital, Taichung City, Taiwan
| | - Mei-Chin Mong
- Department of Food Nutrition and Health Biotechnology, Asia University, Taichung City, Taiwan
| | - Chih-Lung Lin
- Department of Neurosurgery, Asia University Hospital, Taichung City, Taiwan
| | - Mei-Chin Yin
- Department of Food Nutrition and Health Biotechnology, Asia University, Taichung City, Taiwan.,Department of Medical Research, China Medical University Hospital, China Medical University, Taichung City, Taiwan
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Liquid chromatography-mass spectrometry with triazole-bonded stationary phase for N-methyl-d-aspartate receptor-related amino acids: development and application in microdialysis studies. Anal Bioanal Chem 2017; 409:7201-7210. [DOI: 10.1007/s00216-017-0682-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/21/2017] [Accepted: 09/27/2017] [Indexed: 10/18/2022]
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Umino A, Ishiwata S, Iwama H, Nishikawa T. Evidence for Tonic Control by the GABA A Receptor of Extracellular D-Serine Concentrations in the Medial Prefrontal Cortex of Rodents. Front Mol Neurosci 2017; 10:240. [PMID: 28824371 PMCID: PMC5539225 DOI: 10.3389/fnmol.2017.00240] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 07/17/2017] [Indexed: 11/18/2022] Open
Abstract
Endogenous D-serine is a putative dominant co-agonist for the N-methyl-D-aspartate glutamate receptor (NMDAR) in the mammalian forebrain. Although the NMDAR regulates the higher order brain functions by interacting with various neurotransmitter systems, the possible interactions between D-serine and an extra-glutamatergic system largely remain elusive. For the first time, we show in the rat and mouse using an in vivo microdialysis technique that the extracellular D-serine concentrations are under tonic increasing control by a major inhibitory transmitter, GABA, via the GABAA (GABAAR) in the medial prefrontal cortex (mPFC). Thus, an intra-mPFC infusion of a selective GABAAR antagonist, bicuculline (BIC), caused a concentration-dependent and reversible decrease in the extracellular levels of D-serine in the rat mPFC without affecting those of another intrinsic NMDAR coagonist, glycine and an NMDAR agonist, L-glutamate. The decreasing effects of BIC were eliminated by co-infusion of a selective GABAA agonist, muscimol (MUS) and were mimicked by a GABAA antagonist, gabazine (GBZ). In contrast, selective blockade of the GABAB or homomeric ρGABAA (formerly GABAC) receptor by saclofen or (1,2,5,6-tetrahydropyridin-4-yl)-methylphosphinic acid (TPMPA), respectively, failed to downregulate the prefrontal extracellular D-serine levels. Moreover, the local BIC application attenuated the ability of NMDA given to the mPFC to increase the cortical extracellular concentrations of taurine, indicating the hypofunction of the NMDAR. Finally, in the mouse mPFC, the reduction of the extracellular D-serine levels by a local injection of BIC into the prefrontal portion was replicated, and was precluded by inhibition of the neuronal or glial activity by co-local injection with tetrodotoxin (TTX) or fluorocitrate (Fluo), respectively. These findings suggest that the GABAAR-mediated regulation of the D-serine signaling may exert fine-tuning of the NMDAR function and require both neuronal and glial activities in the mammalian mPFC.
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Affiliation(s)
- Asami Umino
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental UniversityTokyo, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental UniversityTokyo, Japan
| | - Sayuri Ishiwata
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental UniversityTokyo, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental UniversityTokyo, Japan
| | - Hisayuki Iwama
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental UniversityTokyo, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental UniversityTokyo, Japan
| | - Toru Nishikawa
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental UniversityTokyo, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental UniversityTokyo, Japan
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Sakimura K, Nakao K, Yoshikawa M, Suzuki M, Kimura H. A novel Na(+) -Independent alanine-serine-cysteine transporter 1 inhibitor inhibits both influx and efflux of D-Serine. J Neurosci Res 2016; 94:888-95. [PMID: 27302861 DOI: 10.1002/jnr.23772] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 04/15/2016] [Accepted: 05/06/2016] [Indexed: 01/28/2023]
Abstract
NMDA receptor dysfunctions are hypothesized to underlie the pathophysiology of schizophrenia, and treatment with D-serine (D-Ser), an NMDA receptor coagonist, may improve the clinical symptoms of schizophrenia. Thus, upregulating the synaptic D-Ser level is a novel strategy for schizophrenia treatment. Na(+) -independent alanine-serine-cysteine transporter 1 (asc-1) is a transporter responsible for regulating the extracellular D-Ser levels in the brain. In this study, we discovered a novel asc-1 inhibitor, (+)-amino(1-(3,5-dichlorophenyl)-3,5-dimethyl-1H-pyrazol-4-yl)acetic acid (ACPP), and assessed its pharmacological profile. ACPP inhibited the D-[(3) H]Ser uptake in human asc-1-expressing CHO cells and rat primary neurons with IC50 values of 0.72 ± 0.13 and 0.89 ± 0.30 μM, respectively. In accordance with the lower asc-1 expression levels in astrocytes, ACPP did not inhibit D-Ser uptake in rat primary astrocytes. In a microdialysis study, ACPP dose dependently decreased the extracellular D-Ser levels in the rat hippocampus under the same conditions in which the asc-1 inhibitor S-methyl-L-cysteine (SMLC) increased it. To obtain insights into this difference, we conducted a D-[(3) H]Ser efflux assay using asc-1-expressing CHO cells. ACPP inhibited D-[(3) H]Ser efflux, whereas SMLC increased it. These results suggest that ACPP is a novel inhibitor of asc-1. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Katsuya Sakimura
- CNS Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Kanagawa, Japan
| | - Kenji Nakao
- Biomolecular Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Kanagawa, Japan
| | - Masato Yoshikawa
- Inflammation Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Kanagawa, Japan
| | - Motohisa Suzuki
- CNS Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Kanagawa, Japan
| | - Haruhide Kimura
- CNS Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Kanagawa, Japan
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Ishiwata S, Umino A, Balu DT, Coyle JT, Nishikawa T. Neuronal serine racemase regulates extracellular D-serine levels in the adult mouse hippocampus. J Neural Transm (Vienna) 2015; 122:1099-103. [PMID: 25782690 DOI: 10.1007/s00702-015-1388-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 02/25/2015] [Indexed: 10/23/2022]
Abstract
In the hippocampus of mice lacking the gene for serine racemase (SR), a D-serine synthesizing enzyme, in the CaMKIIα-expressing neurons, we observed a significant decrease in the extracellular concentration of D-serine, a coagonist for the N-methyl-D-aspartate type glutamate receptor (NMDAR), and NMDAR hypofunction as revealed by diminished extracellular taurine concentrations after an intra-hippocampal NMDA infusion when compared to the wild type controls. Therefore, the neuronal SR could regulate the extracellular D-serine signaling responsible for NMDAR activation in the hippocampus.
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Affiliation(s)
- Sayuri Ishiwata
- Department of Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
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Liu CL, Hsia TC, Yin MC. s-Methyl cysteine enhanced survival of nerve growth factor differentiated PC12 cells under hypoxic conditions. Food Funct 2014; 5:1125-33. [DOI: 10.1039/c3fo60689a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A nerve growth factor-differentiated PC12 cell line was used to investigate the protective effects ofs-methyl cysteine (SMC) at 1, 2, 4, and 8 μM under oxygen–glucose deprivation (OGD) conditions.
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Affiliation(s)
- Chun-lin Liu
- Department of Neurosurgery
- China Medical University Hospital
- Taichung City, Taiwan
| | - Te-chun Hsia
- Department of Respiratory Therapy
- China Medical University
- Taichung City, Taiwan
| | - Mei-chin Yin
- Department of Health and Nutrition Biotechnology
- Asia University
- Taichung City, Taiwan
- Department of Nutrition
- China Medical University
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12
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Maucler C, Pernot P, Vasylieva N, Pollegioni L, Marinesco S. In vivo D-serine hetero-exchange through alanine-serine-cysteine (ASC) transporters detected by microelectrode biosensors. ACS Chem Neurosci 2013; 4:772-81. [PMID: 23581544 DOI: 10.1021/cn4000549] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
D-serine, a co-agonist of N-methyl D-aspartate (NMDA) receptors, has been implicated in neurological and psychiatric disorders such as cerebral ischemia, lateral amyotrophic sclerosis, or schizophrenia. D-serine signaling represents an important pharmacological target for treating these diseases; however, the biochemical mechanisms controlling extracellular D-serine levels in vivo are still unclear. D-serine heteroexchange through small neutral amino acid transporters has been shown in cell cultures and brain slices and could provide a biochemical mechanism for the control of D-serine extracellular concentration in vivo. Alternatively, exocytotic D-serine release has also been proposed. In this study, the dynamics of D-serine release and clearance were explored in vivo on a second-by-second time scale using microelectrode biosensors. The rate of D-serine clearance in the rat frontal cortex after a microionophoretic injection revealed a transporter-mediated uptake mechanism. D-serine uptake was blocked by small neutral l-amino acids, implicating alanine-serine-cysteine (ASC) transporters, in particular high affinity Asc-1 and low affinity ASCT2 transporters. Interestingly, changes in alanine, serine, or threonine levels resulted in D-serine release through ASC transporters. Asc-1, but not ASCT2, appeared to release D-serine in response to changes in amino acid concentrations. Finally, neuronal silencing by tetrodotoxin increased D-serine extracellular concentration by an ASC-transporter-dependent mechanism. Together, these results indicate that D-serine heteroexchange through ASC transporters is present in vivo and may constitute a key component in the regulation of D-serine extracellular concentration.
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Affiliation(s)
- Caroline Maucler
- INSERM U1028; CNRS UMR5292 Lyon Neuroscience Research Center, AniRA-Neurochem technological platform, team WAKING, Lyon F-69000, France
- Université Claude Bernard Lyon 1, Lyon F-69000, France
| | - Pierre Pernot
- INSERM U1028; CNRS UMR5292 Lyon Neuroscience Research Center, AniRA-Neurochem technological platform, team WAKING, Lyon F-69000, France
- Université Claude Bernard Lyon 1, Lyon F-69000, France
| | - Natalia Vasylieva
- INSERM U1028; CNRS UMR5292 Lyon Neuroscience Research Center, AniRA-Neurochem technological platform, team WAKING, Lyon F-69000, France
- Université Claude Bernard Lyon 1, Lyon F-69000, France
- Institut de nanotechnologie de Lyon, CNRS UMR-5270, INSA de Lyon, France
| | - Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell’Insubria, Varese, Italy
- “The Protein Factory”, Centro Interuniversitario di Ricerca in Biotecnologie Proteiche ICRM-CNR Milano, Politecnico di Milano and Università degli studi dell’Insubria, Italy
| | - Stéphane Marinesco
- INSERM U1028; CNRS UMR5292 Lyon Neuroscience Research Center, AniRA-Neurochem technological platform, team WAKING, Lyon F-69000, France
- Université Claude Bernard Lyon 1, Lyon F-69000, France
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