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Cystine/Glutamate Antiporter in Schizophrenia: From Molecular Mechanism to Novel Biomarker and Treatment. Int J Mol Sci 2021; 22:ijms22189718. [PMID: 34575878 PMCID: PMC8466274 DOI: 10.3390/ijms22189718] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/06/2021] [Accepted: 09/06/2021] [Indexed: 01/04/2023] Open
Abstract
Glutamate, a crucial excitatory neurotransmitter, plays a major role in the modulation of schizophrenia’s pathogenesis. New drug developments for schizophrenia have been prompted by the hypoglutamatergic hypothesis of schizophrenia. The cystine/glutamate antiporter system xc− is related to glutamate-release regulation. Patients with schizophrenia were recently discovered to exhibit downregulation of xc− subunits—the solute carrier (SLC) family 3 member 2 and the SLC family 7 member 11. We searched for relevant studies from 1980, when Bannai and Kitamura first identified the protein subunit system xc− in lung fibroblasts, with the aim of compiling the biological, functional, and pharmacological characteristics of antiporter xc−, which consists of several subunits. Some of them can significantly stimulate the human brain through the glutamate pathway. Initially, extracellular cysteine activates neuronal xc−, causing glutamate efflux. Next, excitatory amino acid transporters enhance the unidirectional transportation of glutamate and sodium. These two biochemical pathways are also crucial to the production of glutathione, a protective agent for neural and glial cells and astrocytes. Investigation of the expression of system xc− genes in the peripheral white blood cells of patients with schizophrenia can facilitate better understanding of the mental disorder and future development of novel biomarkers and treatments for schizophrenia. In addition, the findings further support the hypoglutamatergic hypothesis of schizophrenia.
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de Bartolomeis A, Manchia M, Marmo F, Vellucci L, Iasevoli F, Barone A. Glycine Signaling in the Framework of Dopamine-Glutamate Interaction and Postsynaptic Density. Implications for Treatment-Resistant Schizophrenia. Front Psychiatry 2020; 11:369. [PMID: 32477178 PMCID: PMC7240307 DOI: 10.3389/fpsyt.2020.00369] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/14/2020] [Indexed: 12/14/2022] Open
Abstract
Treatment-resistant schizophrenia (TRS) or suboptimal response to antipsychotics affects almost 30% of schizophrenia (SCZ) patients, and it is a relevant clinical issue with significant impact on the functional outcome and on the global burden of disease. Among putative novel treatments, glycine-centered therapeutics (i.e. sarcosine, glycine itself, D-Serine, and bitopertin) have been proposed, based on a strong preclinical rationale with, however, mixed clinical results. Therefore, a better appraisal of glycine interaction with the other major players of SCZ pathophysiology and specifically in the framework of dopamine - glutamate interactions is warranted. New methodological approaches at cutting edge of technology and drug discovery have been applied to study the role of glycine in glutamate signaling, both at presynaptic and post-synaptic level and have been instrumental for unveiling the role of glycine in dopamine-glutamate interaction. Glycine is a non-essential amino acid that plays a critical role in both inhibitory and excitatory neurotransmission. In caudal areas of central nervous system (CNS), such as spinal cord and brainstem, glycine acts as a powerful inhibitory neurotransmitter through binding to its receptor, i.e. the Glycine Receptor (GlyR). However, glycine also works as a co-agonist of the N-Methyl-D-Aspartate receptor (NMDAR) in excitatory glutamatergic neurotransmission. Glycine concentration in the synaptic cleft is finely tuned by glycine transporters, i.e. GlyT1 and GlyT2, that regulate the neurotransmitter's reuptake, with the first considered a highly potential target for psychosis therapy. Reciprocal regulation of dopamine and glycine in forebrain, glycine modulation of glutamate, glycine signaling interaction with postsynaptic density proteins at glutamatergic synapse, and human genetics of glycinergic pathways in SCZ are tackled in order to highlight the exploitation of this neurotransmitters and related molecules in SCZ and TRS.
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Affiliation(s)
- Andrea de Bartolomeis
- Laboratory of Molecular Psychiatry and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Section of Psychiatry, Department of Neuroscience, Reproductive Science and Odontostomatology, University School of Medicine of Napoli Federico II, Naples, Italy
| | - Mirko Manchia
- Section of Psychiatry, Department of Medical Science and Public Health, University of Cagliari, Cagliari, Italy.,Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
| | - Federica Marmo
- Laboratory of Molecular Psychiatry and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Section of Psychiatry, Department of Neuroscience, Reproductive Science and Odontostomatology, University School of Medicine of Napoli Federico II, Naples, Italy
| | - Licia Vellucci
- Laboratory of Molecular Psychiatry and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Section of Psychiatry, Department of Neuroscience, Reproductive Science and Odontostomatology, University School of Medicine of Napoli Federico II, Naples, Italy
| | - Felice Iasevoli
- Laboratory of Molecular Psychiatry and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Section of Psychiatry, Department of Neuroscience, Reproductive Science and Odontostomatology, University School of Medicine of Napoli Federico II, Naples, Italy
| | - Annarita Barone
- Laboratory of Molecular Psychiatry and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Section of Psychiatry, Department of Neuroscience, Reproductive Science and Odontostomatology, University School of Medicine of Napoli Federico II, Naples, Italy
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Ohnuma T, Nishimon S, Takeda M, Sannohe T, Katsuta N, Arai H. Carbonyl Stress and Microinflammation-Related Molecules as Potential Biomarkers in Schizophrenia. Front Psychiatry 2018; 9:82. [PMID: 29593588 PMCID: PMC5859354 DOI: 10.3389/fpsyt.2018.00082] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 02/28/2018] [Indexed: 12/30/2022] Open
Abstract
This literature review primarily aims to summarize our research, comprising both cross-sectional and longitudinal studies, and discuss the possibility of using microinflammation-related biomarkers as peripheral biomarkers in the diagnosis and monitoring of patients with schizophrenia. To date, several studies have been conducted on peripheral biomarkers to recognize the potential markers for the diagnosis of schizophrenia and to determine the state and effects of therapy in patients with schizophrenia. Research has established a correlation between carbonyl stress, an environmental factor, and the pathophysiology of neuropsychiatric diseases, including schizophrenia. In addition, studies on biomarkers related to these stresses have achieved results that are either replicable or exhibit consistent increases or decreases in patients with schizophrenia. For instance, pentosidine, an advanced glycation end product (AGE), is considerably elevated in patients with schizophrenia; however, low levels of vitamin B6 [a detoxifier of reactive carbonyl compounds (RCOs)] have also been reported in some patients with schizophrenia. Another study on peripheral markers of carbonyl stress in patients with schizophrenia revealed a correlation of higher levels of glyceraldehyde-derived AGEs with higher neurotoxicity and lower levels of soluble receptors capable of diminishing the effects of AGEs. Furthermore, studies on evoked microinflammation-related biomarkers (e.g., soluble tumor necrosis factor receptor 1) have reported relatively consistent results, suggesting the involvement of microinflammation in the pathophysiology of schizophrenia. We believe that our cross-sectional and longitudinal studies as well as various previous inflammation marker studies that could be interpreted from several perspectives, such as mild localized encephalitis and microvascular disturbance, highlighted the importance of early intervention as prevention and distinguished the possible exclusion of inflammations in schizophrenia.
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Affiliation(s)
- Tohru Ohnuma
- Juntendo University Schizophrenia Projects (JUSP), Department of Psychiatry, Faculty of Medicine, Juntendo University, Tokyo, Japan
| | - Shohei Nishimon
- Juntendo University Schizophrenia Projects (JUSP), Department of Psychiatry, Faculty of Medicine, Juntendo University, Tokyo, Japan
| | - Mayu Takeda
- Juntendo University Schizophrenia Projects (JUSP), Department of Psychiatry, Faculty of Medicine, Juntendo University, Tokyo, Japan
| | - Takahiro Sannohe
- Juntendo University Schizophrenia Projects (JUSP), Department of Psychiatry, Faculty of Medicine, Juntendo University, Tokyo, Japan
| | - Narimasa Katsuta
- Juntendo University Schizophrenia Projects (JUSP), Department of Psychiatry, Faculty of Medicine, Juntendo University, Tokyo, Japan
| | - Heii Arai
- Juntendo University Schizophrenia Projects (JUSP), Department of Psychiatry, Faculty of Medicine, Juntendo University, Tokyo, Japan
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NMDA-receptor coagonists in serum, plasma, and cerebrospinal fluid of schizophrenia patients: A meta-analysis of case–control studies. Neurosci Biobehav Rev 2013; 37:1587-96. [DOI: 10.1016/j.neubiorev.2013.06.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 06/03/2013] [Accepted: 06/10/2013] [Indexed: 02/04/2023]
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Cacabelos R, Cacabelos P, Aliev G. Genomics of schizophrenia and pharmacogenomics of antipsychotic drugs. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/ojpsych.2013.31008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Nunes EA, MacKenzie EM, Rossolatos D, Perez-Parada J, Baker GB, Dursun SM. D-serine and schizophrenia: an update. Expert Rev Neurother 2012; 12:801-12. [PMID: 22853788 DOI: 10.1586/ern.12.65] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Considering the lengthy history of pharmacological treatment of schizophrenia, the development of novel antipsychotic agents targeting the glutamatergic system is relatively new. A glutamatergic deficit has been proposed to underlie many of the symptoms typically observed in schizophrenia, particularly the negative and cognitive symptoms (which are less likely to respond to current treatments). D-serine is an important coagonist of the glutamate NMDA receptor, and accumulating evidence suggests that D-serine levels and/or activity may be dysfunctional in schizophrenia and that facilitation of D-serine transmission could provide a significant therapeutic breakthrough, especially where conventional treatments have fallen short. A summary of the relevant animal data, as well as genetic studies and clinical trials examining D-serine as an adjunct to standard antipsychotic therapy, is provided in this article. Together, the evidence suggests that research on the next generation of antipsychotic agents should include studies on increasing brain levels of D-serine or mimicking its action on the NMDA receptor.
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Affiliation(s)
- Emerson A Nunes
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
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Yamanaka M, Miyoshi Y, Ohide H, Hamase K, Konno R. d-Amino acids in the brain and mutant rodents lacking d-amino-acid oxidase activity. Amino Acids 2012; 43:1811-21. [DOI: 10.1007/s00726-012-1384-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Accepted: 07/30/2012] [Indexed: 12/27/2022]
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d-Amino acid metabolism in mammals: Biosynthesis, degradation and analytical aspects of the metabolic study. J Chromatogr B Analyt Technol Biomed Life Sci 2011; 879:3162-8. [DOI: 10.1016/j.jchromb.2011.06.028] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2010] [Revised: 06/15/2011] [Accepted: 06/15/2011] [Indexed: 12/28/2022]
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The association of schizophrenia risk D-amino acid oxidase polymorphisms with sensorimotor gating, working memory and personality in healthy males. Neuropsychopharmacology 2011; 36:1677-88. [PMID: 21471957 PMCID: PMC3138651 DOI: 10.1038/npp.2011.49] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
There is evidence supporting a role for the D-amino acid oxidase (DAO) locus in schizophrenia. This study aimed to determine the relationship of five single-nucleotide polymorphisms (SNPs) within the DAO gene identified as promising schizophrenia risk genes (rs4623951, rs2111902, rs3918346, rs3741775, and rs3825251) to acoustic startle, prepulse inhibition (PPI), working memory, and personality dimensions. A highly homogeneous study entry cohort (n = 530) of healthy, young male army conscripts (n = 703) originating from the Greek LOGOS project (Learning On Genetics Of Schizophrenia Spectrum) underwent PPI of the acoustic startle reflex, working memory, and personality assessment. The QTPHASE from the UNPHASED package was used for the association analysis of each SNP or haplotype data, with p-values corrected for multiple testing by running 10,000 permutations of the data. The rs4623951_T-rs3741775_G and rs4623951_T-rs2111902_T diplotypes were associated with reduced PPI and worse performance in working memory tasks and a personality pattern characterized by attenuated anxiety. Median stratification analysis of the risk diplotype group (ie, those individuals homozygous for the T and G alleles (TG+)) showed reduced PPI and working memory performance only in TG+ individuals with high trait anxiety. The rs4623951_T allele, which is the DAO polymorphism most strongly associated with schizophrenia, might tag a haplotype that affects PPI, cognition, and personality traits in general population. Our findings suggest an influence of the gene in the neural substrate mediating sensorimotor gating and working memory, especially when combined with high anxiety and further validate DAO as a candidate gene for schizophrenia and spectrum disorders.
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Papagni SA, Mechelli A, Prata DP, Kambeitz J, Fu CH, Picchioni M, Walshe M, Toulopoulou T, Bramon E, Murray RM, Collier DA, Bellomo A, McGuire P. Differential effects of DAAO on regional activation and functional connectivity in schizophrenia, bipolar disorder and controls. Neuroimage 2011; 56:2283-91. [DOI: 10.1016/j.neuroimage.2011.03.037] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 02/10/2011] [Accepted: 03/14/2011] [Indexed: 01/02/2023] Open
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Lin CH, Lane HY, Tsai GE. Glutamate signaling in the pathophysiology and therapy of schizophrenia. Pharmacol Biochem Behav 2011; 100:665-77. [PMID: 21463651 DOI: 10.1016/j.pbb.2011.03.023] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 03/14/2011] [Accepted: 03/28/2011] [Indexed: 11/26/2022]
Abstract
Glutamatergic neurotransmission, particularly through the N-methyl-d-aspartate (NMDA) receptor, has drawn attention for its role in the pathophysiology of schizophrenia. This paper reviews the neurodevelopmental origin and genetic susceptibility of schizophrenia relevant to NMDA neurotransmission, and discusses the relationship between NMDA hypofunction and different domains of symptom in schizophrenia as well as putative treatment modality for the disorder. A series of clinical trials and a meta-analysis which compared currently available NMDA-enhancing agents suggests that glycine, d-serine, and sarcosine are more efficacious than d-cycloserine in improving the overall psychopathology of schizophrenia without side effect or safety concern. In addition, enhancing glutamatergic neurotransmission via activating the AMPA receptor, metabotropic glutamate receptor or inhibition of d-amino acid oxidase (DAO) is also reviewed. More studies are needed to determine the NMDA vulnerability in schizophrenia and to confirm the long-term efficacy, functional outcome, and safety of these NMDA-enhancing agents in schizophrenic patients, particularly those with refractory negative and cognitive symptoms, or serious adverse effects while taking the existing antipsychotic agents.
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Affiliation(s)
- Chieh-Hsin Lin
- Department of Psychiatry, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan
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Labrie V, Wong AHC, Roder JC. Contributions of the D-serine pathway to schizophrenia. Neuropharmacology 2011; 62:1484-503. [PMID: 21295046 DOI: 10.1016/j.neuropharm.2011.01.030] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2010] [Revised: 01/16/2011] [Accepted: 01/19/2011] [Indexed: 01/30/2023]
Abstract
The glutamate neurotransmitter system is one of the major candidate pathways for the pathophysiology of schizophrenia, and increased understanding of the pharmacology, molecular biology and biochemistry of this system may lead to novel treatments. Glutamatergic hypofunction, particularly at the NMDA receptor, has been hypothesized to underlie many of the symptoms of schizophrenia, including psychosis, negative symptoms and cognitive impairment. This review will focus on D-serine, a co-agonist at the NMDA receptor that in combination with glutamate, is required for full activation of this ion channel receptor. Evidence implicating D-serine, NMDA receptors and related molecules, such as D-amino acid oxidase (DAO), G72 and serine racemase (SRR), in the etiology or pathophysiology of schizophrenia is discussed, including knowledge gained from mouse models with altered D-serine pathway genes and from preliminary clinical trials with D-serine itself or compounds modulating the D-serine pathway. Abnormalities in D-serine availability may underlie glutamatergic dysfunction in schizophrenia, and the development of new treatments acting through the D-serine pathway may significantly improve outcomes for many schizophrenia patients.
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Affiliation(s)
- Viviane Labrie
- Krembil Family Epigenetics Laboratory, Centre for Addiction and Mental Health, 250 College St, Toronto, ON M5T 1R8, Canada.
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Maekawa M, Ohnishi T, Hashimoto K, Watanabe A, Iwayama Y, Ohba H, Hattori E, Yamada K, Yoshikawa T. Analysis of strain-dependent prepulse inhibition points to a role for Shmt1 (SHMT1) in mice and in schizophrenia. J Neurochem 2010; 115:1374-85. [DOI: 10.1111/j.1471-4159.2010.07039.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Konno R, Hamase K, Maruyama R, Zaitsu K. Mutant mice and rats lacking D-amino acid oxidase. Chem Biodivers 2010; 7:1450-8. [PMID: 20564563 DOI: 10.1002/cbdv.200900303] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
D-amino acid oxidase (DAO) catalyzes oxidative deamination of D-amino acids. Since D-amino acids are considered to be rare in eukaryotes, physiological function of this enzyme has been enigmatic for a long time. Mutant mice lacking DAO were found, and their strain was established. The urine of the mutant mice contained large amounts of D-amino acids. D-Amino acids were also present in their organs and blood. The origin of these D-amino acids was pursued. The results indicate that one of the physiological functions of DAO is the metabolism of D-amino acids of internal and external origin. A large amount of D-serine is shown to exist in the brain of mammals. It binds to the coagonist-binding site of N-methyl-D-aspartate (NMDA) subtype of glutamate receptors and enhances the neurotransmission. DAO metabolizes this D-serine and, therefore, modulates neurotransmission. Mutant mice displayed phenotypes resulting from the enhanced NMDA receptor function. Recent studies have shown that DAO is associated with schizophrenia. Mutant mice were resistant to the drugs which act on NMDA receptors and elicit schizophrenia-like symptoms. Recently, mutant rats lacking DAO have also been found. They were free from D-serine-induced nephrotoxicity, indicating involvement of DAO in this toxicity. The mutant mice and rats lacking DAO would be useful for the elucidation of the physiological functions of DAO and the etiology of neuronal diseases associated with DAO.
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Affiliation(s)
- Ryuichi Konno
- Graduate School of Pharmaceutical Sciences, International University of Health and Welfare, 2600-1 Kitakanemaru, Ohtawara, Tochigi 324-8501, Japan.
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Pollegioni L, Sacchi S. Metabolism of the neuromodulator D-serine. Cell Mol Life Sci 2010; 67:2387-404. [PMID: 20195697 PMCID: PMC11115609 DOI: 10.1007/s00018-010-0307-9] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 01/27/2010] [Accepted: 02/08/2010] [Indexed: 01/09/2023]
Abstract
Over the past years, accumulating evidence has indicated that D-serine is the endogenous ligand for the glycine-modulatory binding site on the NR1 subunit of N-methyl-D-aspartate receptors in various brain areas. D-Serine is synthesized in glial cells and neurons by the pyridoxal-5' phosphate-dependent enzyme serine racemase, and it is released upon activation of glutamate receptors. The cellular concentration of this novel messenger is regulated by both serine racemase isomerization and elimination reactions, as well as by its selective degradation catalyzed by the flavin adenine dinucleotide-containing flavoenzyme D-amino acid oxidase. Here, we present an overview of the current knowledge of the metabolism of D-serine in human brain at the molecular and cellular levels, with a specific emphasis on the brain localization and regulatory pathways of D-serine, serine racemase, and D-amino acid oxidase. Furthermore, we discuss how D-serine is involved with specific pathological conditions related to N-methyl-D-aspartate receptors over- or down-regulation.
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Affiliation(s)
- Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze Molecolari, Università degli studi dell'Insubria, Varese, Italy.
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Ohnuma T, Shibata N, Baba H, Ohi K, Yasuda Y, Nakamura Y, Okochi T, Naitoh H, Hashimoto R, Iwata N, Ozaki N, Takeda M, Arai H. No association between DAO and schizophrenia in a Japanese patient population: a multicenter replication study. Schizophr Res 2010; 118:300-2. [PMID: 20178891 DOI: 10.1016/j.schres.2010.01.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 01/13/2010] [Accepted: 01/29/2010] [Indexed: 11/27/2022]
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Abstract
D-amino acid oxidase (DAO) is a flavoenzyme that metabolizes certain D-amino acids, notably the endogenous N-methyl D-aspartate receptor (NMDAR) co-agonist, D-serine. As such, it has the potential to modulate the function of NMDAR and to contribute to the widely hypothesized involvement of NMDAR signalling in schizophrenia. Three lines of evidence now provide support for this possibility: DAO shows genetic associations with the disorder in several, although not all, studies; the expression and activity of DAO are increased in schizophrenia; and DAO inactivation in rodents produces behavioural and biochemical effects, suggestive of potential therapeutic benefits. However, several key issues remain unclear. These include the regional, cellular and subcellular localization of DAO, the physiological importance of DAO and its substrates other than D-serine, as well as the causes and consequences of elevated DAO in schizophrenia. Herein, we critically review the neurobiology of DAO, its involvement in schizophrenia, and the therapeutic value of DAO inhibition. This review also highlights issues that have a broader relevance beyond DAO itself: how should we weigh up convergent and cumulatively impressive, but individually inconclusive, pieces of evidence regarding the role that a given gene may have in the aetiology, pathophysiology and pharmacotherapy of schizophrenia?
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Williams M. Commentary: Genome-based CNS drug discovery: d-Amino acid oxidase (DAAO) as a novel target for antipsychotic medications: Progress and challenges. Biochem Pharmacol 2009; 78:1360-5. [DOI: 10.1016/j.bcp.2009.06.108] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2009] [Revised: 06/29/2009] [Accepted: 06/29/2009] [Indexed: 12/28/2022]
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Nagai Y, Ohnuma T, Karibe J, Shibata N, Maeshima H, Baba H, Hatano T, Hanzawa R, Arai H. No genetic association between the SLC1A2 gene and Japanese patients with schizophrenia. Neurosci Lett 2009; 463:223-7. [DOI: 10.1016/j.neulet.2009.07.092] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 07/18/2009] [Accepted: 07/30/2009] [Indexed: 01/18/2023]
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