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Katane M, Homma H. Biosynthesis and Degradation of Free D-Amino Acids and Their Physiological Roles in the Periphery and Endocrine Glands. Biol Pharm Bull 2024; 47:562-579. [PMID: 38432912 DOI: 10.1248/bpb.b23-00485] [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] [Indexed: 03/05/2024]
Abstract
It was long believed that D-amino acids were either unnatural isomers or laboratory artifacts, and that the important functions of amino acids were exerted only by L-amino acids. However, recent investigations have revealed a variety of D-amino acids in mammals that play important roles in physiological functions, including free D-serine and D-aspartate that are crucial in the central nervous system. The functions of several D-amino acids in the periphery and endocrine glands are also receiving increasing attention. Here, we present an overview of recent advances in elucidating the physiological roles of D-amino acids, especially in the periphery and endocrine glands.
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Affiliation(s)
- Masumi Katane
- Medicinal Research Laboratories, Graduate School of Pharmaceutical Sciences, Kitasato University
| | - Hiroshi Homma
- Laboratory of Analytical Chemistry, Graduate School of Pharmaceutical Sciences, Kitasato University
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2
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Koyama H, Takahashi Y, Matori S, Kuniyoshi H, Kurose K. A newly identified enzyme from Japanese common squid Todarodes pacificus has the ability to biosynthesize d-aspartate. Arch Biochem Biophys 2023; 750:109809. [PMID: 37925062 DOI: 10.1016/j.abb.2023.109809] [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: 06/30/2023] [Revised: 10/26/2023] [Accepted: 10/30/2023] [Indexed: 11/06/2023]
Abstract
Amino acids exist in two chiral forms, namely L and D. Although l-amino acids are predominant in vivo, certain limited circumstances have reported the usage of d-amino acids. d-aspartate (Asp), among them, plays crucial physiological roles in living organisms and is biosynthesized from L-Asp by the enzyme named aspartate racemase (AspRase). D-Asp is known to accumulate in large amounts in the nervous system of cephalopods. To understand the function of D-Asp in nervous system in more detail, it is necessary to elucidate its metabolic pathway; however, AspRase gene has not been identified in cephalopods as in the case of mammals. In this study, we successfully identified a novel gene encoding AspRase from the optic ganglion of Japanese common squid Todarodes pacificus. Our discovery of the squid AspRase challenges the prevailing assumption that AspRases across different animals share similar structures. Surprisingly, the squid AspRase is a unique enzyme that differs significantly from known AspRases, being structurally and phylogenetically related to aspartate aminotransferase (AST) and possessing both AspRase and AST activities. The optimum pH and temperature for AspRase activity using L-Asp as a substrate are approximately 7.0 and 20 °C, respectively. Moreover, we have found that AspRase activity is enhanced in the presence of 2-oxoacids. These findings have far-reaching implications for the understanding of enzymology and suggest that yet-to-be-identified mammalian AspRases may also be phylogenetically related to AST, rather than conventional AspRases. Furthermore, our results provide valuable insights into the evolution of the D-Asp biosynthetic pathway.
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Affiliation(s)
- Hiroki Koyama
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, 108-8477, Japan.
| | - Yui Takahashi
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, 108-8477, Japan
| | - San Matori
- Program of Food and AgriLife Science, Graduate School of Integrated Sciences for Life, Hiroshima University Higashi-hiroshima, 739-8528, Japan
| | - Hisato Kuniyoshi
- Program of Food and AgriLife Science, Graduate School of Integrated Sciences for Life, Hiroshima University Higashi-hiroshima, 739-8528, Japan
| | - Kouichi Kurose
- Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, 108-8477, Japan
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3
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Ding K, Xu Q, Zhang X, Liu S. Metabolomic insights into neurological effects of BDE-47 exposure in the sea cucumber Apostichopus japonicus. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 266:115558. [PMID: 37820477 DOI: 10.1016/j.ecoenv.2023.115558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/21/2023] [Accepted: 10/06/2023] [Indexed: 10/13/2023]
Abstract
The persistent organic pollutant 2,2',4,4'-Tetrabromodiphenyl ether (BDE-47), a prevalent congener among polybrominated diphenyl ethers (PBDEs), exhibits potent bioaccumulation and toxicity. Despite extensive research into the adverse effects of BDE-47, its neurotoxicity in sea cucumbers remains unexplored. Given the crucial role of the sea cucumber's nervous system in survival and adaptation, evaluating the impacts of BDE-47 is vital for sustainable aquaculture and consumption. In this study, we employed ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Triple-TOF-MS) to analyze metabolomic changes in neuro-related tissues of Apostichopus japonicus exposed to low (0.1 µg/L), medium (1.0 µg/L), and high (10.0 µg/L) BDE-47 concentrations. We identified significantly changed metabolites in each exposure group (87 in low, 79 in medium, and 102 in high), affecting a variety of physiological processes such as steroid hormone balance, nucleotide metabolism, energy metabolism, neurotransmitter levels, and neuroprotection. In addition, we identified concentration-dependent, common, and some other metabolic responses in the neuro-related tissues. Our findings reveal critical insights into the neurotoxic effects of BDE-47 in sea cucumbers and contribute to risk assessment related to BDE-47 exposure in the sea cucumber industry, paving the way for future neurotoxicological research in invertebrates.
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Affiliation(s)
- Kui Ding
- Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China; Laboratory of Marine Ecology and Environmental Science, National Laboratory for Marine Science and Technology, Qingdao 266061, China; CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
| | - Qinzeng Xu
- Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China; Laboratory of Marine Ecology and Environmental Science, National Laboratory for Marine Science and Technology, Qingdao 266061, China
| | - Xuelei Zhang
- Key Laboratory of Marine Eco-Environmental Science and Technology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China; Laboratory of Marine Ecology and Environmental Science, National Laboratory for Marine Science and Technology, Qingdao 266061, China
| | - Shilin Liu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
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Wang C, Liu Y, Liu X, Zhang Y, Yan X, Deng X, Shi J. Scutellarin Alleviates Ischemic Brain Injury in the Acute Phase by Affecting the Activity of Neurotransmitters in Neurons. Molecules 2023; 28:molecules28073181. [PMID: 37049959 PMCID: PMC10095904 DOI: 10.3390/molecules28073181] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/16/2023] [Accepted: 03/27/2023] [Indexed: 04/14/2023] Open
Abstract
Cerebral ischemic stroke is a common neuron loss disease that is caused by the interruption of the blood supply to the brain. In order to enhance the CIS outcome, both identifying the treatment target of ischemic brain damage in the acute phase and developing effective therapies are urgently needed. Scutellarin had been found to be beneficial to ischemic injuries and has been shown to have potent effects in clinical application on both stroke and myocardial infarction. However, whether scutellarin improves ischemic brain damage in the acute phase remains unknown. In this study, the protective effects of scutellarin on ischemic brain damage in the acute phase (within 12 h) were illustrated. In middle cerebral artery occlusion and reperfusion (MCAO/R) modeling rats, the Z-Longa score was significantly down-regulated by 25% and 23.1%, and the brain infarct size was reduced by 26.95 ± 0.03% and 25.63 ± 0.02% when responding to high-dose and low-dose scutellarin treatments, respectively. H&E and TUNEL staining results indicated that the neuron loss of the ischemic region was improved under scutellarin treatment. In order to investigate the mechanism of scutellarin's effects on ischemic brain damage in the acute phase, changes in proteins and metabolites were analyzed. The suppression of scutellarin on the glutamate-inducing excitatory amino acid toxicity was strongly indicated in the study of both proteomics and metabolomics. A molecular docking experiment presented strong interactions between scutellarin and glutamate receptors, which score much higher than those of memantine. Further, by performing a parallel reaction monitoring-mass spectrometry (PRM-MS) study on both the cortex and hippocampus tissue of the ischemic region, we screened the scutellarin-regulating molecules that are involved in both the release and transportation of neurotransmitters. It was found that the aberrant levels of glutamate receptors, including EAAT2, GRIN1, GRIN2B, and GRM1, as well as of other glutamatergic pathway-involving proteins, including CAMKK2, PSD95, and nNOS, were significantly regulated in the ischemic cortex. In the hippocampus, EAAT2, GRIN1, nNOS, and CAM were significantly regulated. Taken together, scutellarin exerts potent effects on ischemic brain damage in the acute phase by regulating the activity of neurotransmitters and reducing the toxicity of excitatory amino acids in in neurons.
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Affiliation(s)
- Chunguo Wang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100105, China
- Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100105, China
| | - Yaoyu Liu
- School of Trational Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100105, China
| | - Xi Liu
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100105, China
| | - Yuting Zhang
- Beijing Research Institute of Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100105, China
| | - Xingli Yan
- School of Trational Chinese Medicine, Beijing University of Chinese Medicine, Beijing 100105, China
| | - Xinqi Deng
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100091, China
| | - Jinli Shi
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100105, China
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de Dios SMR, Hass JL, Graham DL, Kumar N, Antony AE, Morton MD, Berkowitz DB. Information-Rich, Dual-Function 13C/ 2H-Isotopic Crosstalk NMR Assay for Human Serine Racemase (hSR) Provides a PLP-Enzyme "Partitioning Fingerprint" and Reveals Disparate Chemotypes for hSR Inhibition. J Am Chem Soc 2023; 145:3158-3174. [PMID: 36696670 PMCID: PMC11103274 DOI: 10.1021/jacs.2c12774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The first dual-function assay for human serine racemase (hSR), the only bona fide racemase in human biology, is reported. The hSR racemization function is essential for neuronal signaling, as the product, d-serine (d-Ser), is a potent N-methyl d-aspartate (NMDA) coagonist, important for learning and memory, with dysfunctional d-Ser-signaling being observed in some neuronal disorders. The second hSR function is β-elimination and gives pyruvate; this activity is elevated in colorectal cancer. This new NMR-based assay allows one to monitor both α-proton-exchange chemistry and β-elimination using only the native l-Ser substrate and hSR and is the most sensitive such assay. The assay judiciously employs segregated dual 13C-labeling and 13C/2H crosstalk, exploiting both the splitting and shielding effects of deuterium. The assay is deployed to screen a 1020-compound library and identifies an indolo-chroman-2,4-dione inhibitor family that displays allosteric site binding behavior (noncompetitive inhibition vs l-Ser substrate; competitive inhibition vs adenosine 5'-triphosphate (ATP)). This assay also reveals important mechanistic information for hSR; namely, that H/D exchange is ∼13-fold faster than racemization, implying that K56 protonates the carbanionic intermediate on the si-face much faster than does S84 on the re-face. Moreover, the 13C NMR peak pattern seen is suggestive of internal return, pointing to K56 as the likely enamine-protonating residue for β-elimination. The 13C/2H-isotopic crosstalk assay has also been applied to the enzyme tryptophan synthase and reveals a dramatically different partition ratio in this active site (β-replacement: si-face protonation ∼6:1 vs β-elimination: si-face protonation ∼1:3.6 for hSR), highlighting the value of this approach for fingerprinting the pyridoxal phosphate (PLP) enzyme mechanism.
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Affiliation(s)
| | | | | | - Nivesh Kumar
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588 USA
| | - Aina E. Antony
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588 USA
| | - Martha D. Morton
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588 USA
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OYAIDE M, ISHII C, FUJII A, AKITA T, MITA M, NAGANO M, HAMASE K. Enantioselective Determination of Hydroxy Amino Acids in Japanese Traditional Amber Rice Vinegars. CHROMATOGRAPHY 2022. [DOI: 10.15583/jpchrom.2022.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Mai OYAIDE
- Graduate School of Pharmaceutical Sciences, Kyushu University
| | - Chiharu ISHII
- Graduate School of Pharmaceutical Sciences, Kyushu University
| | | | - Takeyuki AKITA
- Graduate School of Pharmaceutical Sciences, Kyushu University
| | | | | | - Kenji HAMASE
- Graduate School of Pharmaceutical Sciences, Kyushu University
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7
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Brinca AT, Ramalhinho AC, Sousa Â, Oliani AH, Breitenfeld L, Passarinha LA, Gallardo E. Follicular Fluid: A Powerful Tool for the Understanding and Diagnosis of Polycystic Ovary Syndrome. Biomedicines 2022; 10:1254. [PMID: 35740276 PMCID: PMC9219683 DOI: 10.3390/biomedicines10061254] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 02/04/2023] Open
Abstract
Polycystic ovary syndrome (PCOS) represents one of the leading causes of anovulatory infertility and affects 5% to 20% of women worldwide. Until today, both the subsequent etiology and pathophysiology of PCOS remain unclear, and patients with PCOS that undergo assisted reproductive techniques (ART) might present a poor to exaggerated response, low oocyte quality, ovarian hyperstimulation syndrome, as well as changes in the follicular fluid metabolites pattern. These abnormalities originate a decrease of Metaphase II (MII) oocytes and decreased rates for fertilization, cleavage, implantation, blastocyst conversion, poor egg to follicle ratio, and increased miscarriages. Focus on obtaining high-quality embryos has been taken into more consideration over the years. Nowadays, the use of metabolomic analysis in the quantification of proteins and peptides in biological matrices might predict, with more accuracy, the success in assisted reproductive technology. In this article, we review the use of human follicular fluid as the matrix in metabolomic analysis for diagnostic and ART predictor of success for PCOS patients.
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Affiliation(s)
- Ana Teresa Brinca
- Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, 6200-506 Covilhã, Portugal; (A.T.B.); (Â.S.); (L.B.)
| | - Ana Cristina Ramalhinho
- Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, 6200-506 Covilhã, Portugal; (A.T.B.); (Â.S.); (L.B.)
- Assisted Reproduction Laboratory of Academic Hospital of Cova da Beira, 6200-251 Covilhã, Portugal;
- C4-Cloud Computing Competence Centre, University of Beira Interior, 6201-001 Covilhã, Portugal
| | - Ângela Sousa
- Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, 6200-506 Covilhã, Portugal; (A.T.B.); (Â.S.); (L.B.)
| | - António Hélio Oliani
- Assisted Reproduction Laboratory of Academic Hospital of Cova da Beira, 6200-251 Covilhã, Portugal;
- São José do Rio Preto School of Medicine, Gynaecology and Obstetrics, São José do Rio Preto 15090-000, Brazil
| | - Luiza Breitenfeld
- Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, 6200-506 Covilhã, Portugal; (A.T.B.); (Â.S.); (L.B.)
- C4-Cloud Computing Competence Centre, University of Beira Interior, 6201-001 Covilhã, Portugal
| | - Luís A. Passarinha
- Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, 6200-506 Covilhã, Portugal; (A.T.B.); (Â.S.); (L.B.)
- UCIBIO–Applied Molecular Biosciences Unit, Departament of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal
- Associate Laboratory i4HB-Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516 Caparica, Portugal
- Laboratório de Fármaco-Toxicologia, UBIMedical, University of Beira Interior, 6200-284 Covilhã, Portugal
| | - Eugenia Gallardo
- Health Sciences Research Centre, Faculty of Health Sciences, University of Beira Interior, 6200-506 Covilhã, Portugal; (A.T.B.); (Â.S.); (L.B.)
- Laboratório de Fármaco-Toxicologia, UBIMedical, University of Beira Interior, 6200-284 Covilhã, Portugal
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8
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Human Serine Racemase Weakly Binds the Third PDZ Domain of PSD-95. Int J Mol Sci 2022; 23:ijms23094959. [PMID: 35563349 PMCID: PMC9105370 DOI: 10.3390/ijms23094959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/13/2022] [Accepted: 04/27/2022] [Indexed: 11/16/2022] Open
Abstract
Human serine racemase (hSR) is a pyridoxal-5'-phosphate (PLP)-dependent dimer that catalyzes the formation of D-serine from L-serine, as well as the dehydration of both L- and D-serine to pyruvate and ammonia. As D-serine is a co-agonist of N-methyl-D-aspartate receptors (NMDARs), hSR is a key enzyme in glutamatergic neurotransmission. hSR activity is finely regulated by Mg2+, ATP, post-translational modifications, and the interaction with protein partners. In particular, the C-terminus of murine SR binds the third PDZ domain (PDZ3) of postsynaptic density protein 95 (PSD-95), a member of the membrane-associated guanylate kinase (MAGUK) family involved in the trafficking and localization of glutamate receptors. The structural details of the interaction and the stability of the complex have not been elucidated yet. We evaluated the binding of recombinant human PSD-95 PDZ3 to hSR by glutaraldehyde cross-linking, pull-down assays, isothermal titration calorimetry, nuclear magnetic resonance, and enzymatic assays. Overall, a weak interaction was observed, confirming the binding for the human orthologs but supporting the hypothesis that a third protein partner (i.e., stargazin) is required for the regulation of hSR activity by PSD-95 and to stabilize their interaction.
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Sherwood MW, Oliet SHR, Panatier A. NMDARs, Coincidence Detectors of Astrocytic and Neuronal Activities. Int J Mol Sci 2021; 22:7258. [PMID: 34298875 PMCID: PMC8307462 DOI: 10.3390/ijms22147258] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/30/2021] [Accepted: 06/30/2021] [Indexed: 12/18/2022] Open
Abstract
Synaptic plasticity is an extensively studied cellular correlate of learning and memory in which NMDARs play a starring role. One of the most interesting features of NMDARs is their ability to act as a co-incident detector. It is unique amongst neurotransmitter receptors in this respect. Co-incident detection is possible because the opening of NMDARs requires membrane depolarisation and the binding of glutamate. Opening of NMDARs also requires a co-agonist. Although the dynamic regulation of glutamate and membrane depolarization have been well studied in coincident detection, the role of the co-agonist site is unexplored. It turns out that non-neuronal glial cells, astrocytes, regulate co-agonist availability, giving them the ability to influence synaptic plasticity. The unique morphology and spatial arrangement of astrocytes at the synaptic level affords them the capacity to sample and integrate information originating from unrelated synapses, regardless of any pre-synaptic and post-synaptic commonality. As astrocytes are classically considered slow responders, their influence at the synapse is widely recognized as modulatory. The aim herein is to reconsider the potential of astrocytes to participate directly in ongoing synaptic NMDAR activity and co-incident detection.
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Affiliation(s)
- Mark W. Sherwood
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France;
| | | | - Aude Panatier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France;
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10
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Lee CJ, Qiu TA, Sweedler JV. d-Alanine: Distribution, origin, physiological relevance, and implications in disease. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140482. [DOI: 10.1016/j.bbapap.2020.140482] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/19/2020] [Accepted: 06/29/2020] [Indexed: 01/01/2023]
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Michielon A, Marchesani F, Faggiano S, Giaccari R, Campanini B, Bettati S, Mozzarelli A, Bruno S. Human serine racemase is inhibited by glyceraldehyde 3-phosphate, but not by glyceraldehyde 3-phosphate dehydrogenase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1869:140544. [PMID: 32971286 DOI: 10.1016/j.bbapap.2020.140544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/14/2020] [Accepted: 09/19/2020] [Indexed: 11/28/2022]
Abstract
Murine serine racemase (SR), the enzyme responsible for the biosynthesis of the neuromodulator d-serine, was reported to form a complex with glyceraldehyde 3-phosphate dehydrogenase (GAPDH), resulting in SR inhibition. In this work, we investigated the interaction between the two human orthologues. We were not able to observe neither the inhibition nor the formation of the SR-GAPDH complex. Rather, hSR is inhibited by the hGAPDH substrate glyceraldehyde 3-phosphate (G3P) in a time- and concentration-dependent fashion, likely through a covalent reaction of the aldehyde functional group. The inhibition was similar for the two G3P enantiomers but it was not observed for structurally similar aldehydes. We ruled out a mechanism of inhibition based on the competition with either pyridoxal phosphate (PLP) - described for other PLP-dependent enzymes when incubated with small aldehydes - or ATP. Nevertheless, the inhibition time course was affected by the presence of hSR allosteric and orthosteric ligands, suggesting a conformation-dependence of the reaction.
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Affiliation(s)
- Annalisa Michielon
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Francesco Marchesani
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Serena Faggiano
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy; Istituto di Biofisica, CNR, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Roberta Giaccari
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Barbara Campanini
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Stefano Bettati
- Dipartimento di Medicina e Chirurgia, Via Volturno 39, 43125 Parma, Italy
| | - Andrea Mozzarelli
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy; Istituto di Biofisica, CNR, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Stefano Bruno
- Dipartimento di Scienze degli Alimenti e del Farmaco, Università degli Studi di Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy.
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12
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Dalangin R, Kim A, Campbell RE. The Role of Amino Acids in Neurotransmission and Fluorescent Tools for Their Detection. Int J Mol Sci 2020; 21:E6197. [PMID: 32867295 PMCID: PMC7503967 DOI: 10.3390/ijms21176197] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/17/2020] [Accepted: 08/24/2020] [Indexed: 12/20/2022] Open
Abstract
Neurotransmission between neurons, which can occur over the span of a few milliseconds, relies on the controlled release of small molecule neurotransmitters, many of which are amino acids. Fluorescence imaging provides the necessary speed to follow these events and has emerged as a powerful technique for investigating neurotransmission. In this review, we highlight some of the roles of the 20 canonical amino acids, GABA and β-alanine in neurotransmission. We also discuss available fluorescence-based probes for amino acids that have been shown to be compatible for live cell imaging, namely those based on synthetic dyes, nanostructures (quantum dots and nanotubes), and genetically encoded components. We aim to provide tool developers with information that may guide future engineering efforts and tool users with information regarding existing indicators to facilitate studies of amino acid dynamics.
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Affiliation(s)
- Rochelin Dalangin
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; (R.D.); (A.K.)
| | - Anna Kim
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; (R.D.); (A.K.)
| | - Robert E. Campbell
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; (R.D.); (A.K.)
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Bunkyo City, Tokyo 113-0033, Japan
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13
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Bearne SL. Through the Looking Glass: Chiral Recognition of Substrates and Products at the Active Sites of Racemases and Epimerases. Chemistry 2020; 26:10367-10390. [DOI: 10.1002/chem.201905826] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/09/2020] [Indexed: 12/18/2022]
Affiliation(s)
- Stephen L. Bearne
- Department of Biochemistry & Molecular BiologyDepartment of ChemistryDalhousie University Halifax, Nova Scotia B3H 4R2 Canada
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14
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ISHII C, AKITA T, NAGANO M, MITA M, HAMASE K. Determination of Chiral Amino Acids in Various Fermented Products Using a Two-Dimensional HPLC-MS/MS System. CHROMATOGRAPHY 2019. [DOI: 10.15583/jpchrom.2019.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Chiharu ISHII
- Graduate School of Pharmaceutical Sciences, Kyushu University
| | - Takeyuki AKITA
- Graduate School of Pharmaceutical Sciences, Kyushu University
| | | | | | - Kenji HAMASE
- Graduate School of Pharmaceutical Sciences, Kyushu University
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Uda K, Ishizuka N, Edashige Y, Kikuchi A, Radkov AD, Moe LA. Cloning and characterization of a novel aspartate/glutamate racemase from the acorn worm Saccoglossus kowalevskii. Comp Biochem Physiol B Biochem Mol Biol 2019; 232:87-92. [DOI: 10.1016/j.cbpb.2019.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 03/08/2019] [Accepted: 03/14/2019] [Indexed: 02/02/2023]
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Panizzutti R, Fisher M, Garrett C, Man WH, Sena W, Madeira C, Vinogradov S. Association between increased serum d-serine and cognitive gains induced by intensive cognitive training in schizophrenia. Schizophr Res 2019; 207:63-69. [PMID: 29699895 PMCID: PMC9770102 DOI: 10.1016/j.schres.2018.04.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 04/01/2018] [Accepted: 04/04/2018] [Indexed: 02/04/2023]
Abstract
Neuroscience-guided cognitive training induces significant improvement in cognition in schizophrenia subjects, but the biological mechanisms associated with these changes are unknown. In animals, intensive cognitive activity induces increased brain levels of the NMDA-receptor co-agonist d-serine, a molecular system that plays a role in learning-induced neuroplasticity and that may be hypoactive in schizophrenia. Here, we investigated whether training-induced gains in cognition were associated with increases in serum d-serine in outpatients with schizophrenia. Ninety patients with schizophrenia and 53 healthy controls were assessed on baseline serum d-serine, l-serine, and glycine. Schizophrenia subjects performed neurocognitive tests and were assigned to 50 h of either cognitive training of auditory processing systems (N = 47) or a computer games control condition (N = 43), followed by reassessment of cognition and serum amino acids. At study entry, the mean serum d-serine level was significantly lower in schizophrenia subjects vs. healthy subjects, while the glycine levels were significantly higher. There were no significant changes in these measures at a group level after the intervention. However, in the active training group, increased d-serine was significantly and positively correlated with improvements in global cognition and in Verbal Learning. No such associations were observed in the computer games control subjects, and no such associations were found for glycine. d-Serine may be involved in the neurophysiologic changes induced by cognitive training in schizophrenia. Pharmacologic strategies that target d-serine co-agonism of NMDA-receptor functioning may provide a mechanism for enhancing the behavioral effects of intensive cognitive training.
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Affiliation(s)
- Rogerio Panizzutti
- W.M. Keck Foundation Center for Integrative Neurosciences, 675 Nelson Rising Lane, San Francisco, CA, USA; Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, CCS, Cidade Universitaria, Rio de Janeiro, RJ, Brazil; Instituto de Psiquiatria, Universidade Federal do Rio de Janeiro, Av. Venceslau Braz, 71, Rio de Janeiro, RJ, Brazil; Department of Psychiatry, UCSF School of Medicine, 982 Mission St, San Francisco, CA, USA.
| | - Melissa Fisher
- Department of Psychiatry, University of Minnesota, United States
| | - Coleman Garrett
- Department of Psychiatry, School of Medicine, University of California, San Francisco, CA
| | - Wai Hong Man
- Department of Psychiatry, School of Medicine, University of California, San Francisco, CA
| | - Walter Sena
- Biomedical Sciences Institute and Psychiatry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Caroline Madeira
- Biomedical Sciences Institute and Psychiatry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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Graham DL, Beio ML, Nelson DL, Berkowitz DB. Human Serine Racemase: Key Residues/Active Site Motifs and Their Relation to Enzyme Function. Front Mol Biosci 2019; 6:8. [PMID: 30918891 PMCID: PMC6424897 DOI: 10.3389/fmolb.2019.00008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 02/12/2019] [Indexed: 01/06/2023] Open
Abstract
Serine racemase (SR) is the first racemase enzyme to be identified in human biology and converts L-serine to D-serine, an important neuronal signaling molecule that serves as a co-agonist of the NMDA (N-methyl-D-aspartate) receptor. This overview describes key molecular features of the enzyme, focusing on the side chains and binding motifs that control PLP (pyridoxal phosphate) cofactor binding as well as activity modulation through the binding of both divalent cations and ATP, the latter showing allosteric modulation. Discussed are catalytically important residues in the active site including K56 and S84—the si- and re-face bases, respectively,—and R135, a residue that appears to play a critical role in the binding of both negatively charged alternative substrates and inhibitors. The interesting bifurcated mechanism followed by this enzyme whereby substrate L-serine can be channeled either into D-serine (racemization pathway) or into pyruvate (β-elimination pathway) is discussed extensively, as are studies that focus on a key loop region (the so-called “triple serine loop”), the modification of which can be used to invert the normal in vitro preference of this enzyme for the latter pathway over the former. The possible cross-talk between the PLP enzymes hSR and hCBS (human cystathionine β-synthase) is discussed, as the former produces D-serine and the latter produces H2S, both of which stimulate the NMDAR and both of which have been implicated in neuronal infarction pursuant to ischemic stroke. Efforts to gain a more complete mechanistic understanding of these PLP enzymes are expected to provide valuable insights for the development of specific small molecule modulators of these enzymes as tools to study their roles in neuronal signaling and in modulation of NMDAR function.
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Affiliation(s)
- Danielle L Graham
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Matthew L Beio
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - David L Nelson
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - David B Berkowitz
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, United States
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18
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Du S, Wang Y, Alatrash N, Weatherly CA, Roy D, MacDonnell FM, Armstrong DW. Altered profiles and metabolism of l- and d-amino acids in cultured human breast cancer cells vs. non-tumorigenic human breast epithelial cells. J Pharm Biomed Anal 2019; 164:421-429. [DOI: 10.1016/j.jpba.2018.10.047] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 10/24/2018] [Accepted: 10/25/2018] [Indexed: 12/01/2022]
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Raboni S, Marchetti M, Faggiano S, Campanini B, Bruno S, Marchesani F, Margiotta M, Mozzarelli A. The Energy Landscape of Human Serine Racemase. Front Mol Biosci 2019; 5:112. [PMID: 30687716 PMCID: PMC6333871 DOI: 10.3389/fmolb.2018.00112] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/26/2018] [Indexed: 12/17/2022] Open
Abstract
Human serine racemase is a pyridoxal 5′-phosphate (PLP)-dependent dimeric enzyme that catalyzes the reversible racemization of L-serine and D-serine and their dehydration to pyruvate and ammonia. As D-serine is the co-agonist of the N-methyl-D-aspartate receptors for glutamate, the most abundant excitatory neurotransmitter in the brain, the structure, dynamics, function, regulation and cellular localization of serine racemase have been investigated in detail. Serine racemase belongs to the fold-type II of the PLP-dependent enzyme family and structural models from several orthologs are available. The comparison of structures of serine racemase co-crystallized with or without ligands indicates the presence of at least one open and one closed conformation, suggesting that conformational flexibility plays a relevant role in enzyme regulation. ATP, Mg2+, Ca2+, anions, NADH and protein interactors, as well as the post-translational modifications nitrosylation and phosphorylation, finely tune the racemase and dehydratase activities and their relative reaction rates. Further information on serine racemase structure and dynamics resulted from the search for inhibitors with potential therapeutic applications. The cumulative knowledge on human serine racemase allowed obtaining insights into its conformational landscape and into the mechanisms of cross-talk between the effector binding sites and the active site.
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Affiliation(s)
- Samanta Raboni
- Department of Food and Drug, University of Parma, Parma, Italy
| | | | - Serena Faggiano
- Department of Food and Drug, University of Parma, Parma, Italy.,Institute of Biophysics, National Research Council, Pisa, Italy
| | | | - Stefano Bruno
- Department of Food and Drug, University of Parma, Parma, Italy
| | | | | | - Andrea Mozzarelli
- Department of Food and Drug, University of Parma, Parma, Italy.,Institute of Biophysics, National Research Council, Pisa, Italy.,National Institute of Biostructures and Biosystems, Rome, Italy
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Glutamine 89 is a key residue in the allosteric modulation of human serine racemase activity by ATP. Sci Rep 2018; 8:9016. [PMID: 29899358 PMCID: PMC5998037 DOI: 10.1038/s41598-018-27227-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/25/2018] [Indexed: 11/17/2022] Open
Abstract
Serine racemase (SR) catalyses two reactions: the reversible racemisation of L-serine and the irreversible dehydration of L- and D-serine to pyruvate and ammonia. SRs are evolutionarily related to serine dehydratases (SDH) and degradative threonine deaminases (TdcB). Most SRs and TdcBs – but not SDHs – are regulated by nucleotides. SR binds ATP cooperatively and the nucleotide allosterically stimulates the serine dehydratase activity of the enzyme. A H-bond network comprising five residues (T52, N86, Q89, E283 and N316) and water molecules connects the active site with the ATP-binding site. Conservation analysis points to Q89 as a key residue for the allosteric communication, since its mutation to either Met or Ala is linked to the loss of control of activity by nucleotides. We verified this hypothesis by introducing the Q89M and Q89A point mutations in the human SR sequence. The allosteric communication between the active site and the allosteric site in both mutants is almost completely abolished. Indeed, the stimulation of the dehydratase activity by ATP is severely diminished and the binding of the nucleotide is no more cooperative. Ancestral state reconstruction suggests that the allosteric control by nucleotides established early in SR evolution and has been maintained in most eukaryotic lineages.
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22
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Murakami M, Saito M, Yokobori H, Nishimura K, Tanigawa M, Nagata Y. Involvement of C-terminal amino acids of a hyperthermophilic serine racemase in its thermostability. Extremophiles 2017; 22:99-107. [PMID: 29124361 DOI: 10.1007/s00792-017-0980-9] [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: 06/29/2017] [Accepted: 11/03/2017] [Indexed: 11/27/2022]
Abstract
Pyrobaculum islandicum is a hyperthermophilic archaeon that grows optimally at 95-100 °C. In the previous study, we extensively purified a serine racemase from this organism and cloned the gene for overexpression in Escherichia coli (Ohnishi et al. 2008). This enzyme also exhibits highly thermostable L-serine/L-threonine dehydratase activity. In the present study, we aimed to elucidate the molecular mechanisms underlying the high thermostability of this enzyme. A recombinant variant of this enzyme, PiSRvt, constructed by truncating the C-terminal 72 amino acids, was compared with the native enzyme, PiSR. The dehydratase activity of PiSR and PiSRvt was found to owe to a homotrimer and a monomer, respectively, that demonstrated high and moderate thermostability, respectively. These observations reveal that the C-terminal region contributes to monomer trimerization that provides the extreme thermostability.
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Affiliation(s)
- Masahito Murakami
- Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-Ward, Tokyo, 101-8308, Japan
| | - Makoto Saito
- Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-Ward, Tokyo, 101-8308, Japan
| | - Hirokazu Yokobori
- Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-Ward, Tokyo, 101-8308, Japan
| | - Katsushi Nishimura
- Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-Ward, Tokyo, 101-8308, Japan
| | - Minoru Tanigawa
- Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-Ward, Tokyo, 101-8308, Japan
| | - Yoko Nagata
- Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Chiyoda-Ward, Tokyo, 101-8308, Japan.
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Haitjema S, Meddens CA, van der Laan SW, Kofink D, Harakalova M, Tragante V, Foroughi Asl H, van Setten J, Brandt MM, Bis JC, O’Donnell C, Cheng C, Hoefer IE, Waltenberger J, Biessen E, Jukema JW, Doevendans PA, Nieuwenhuis EE, Erdmann J, Björkegren JL, Pasterkamp G, Asselbergs FW, den Ruijter HM, Mokry M. Additional Candidate Genes for Human Atherosclerotic Disease Identified Through Annotation Based on Chromatin Organization. ACTA ACUST UNITED AC 2017; 10:CIRCGENETICS.116.001664. [DOI: 10.1161/circgenetics.116.001664] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 12/12/2016] [Indexed: 11/16/2022]
Abstract
Background—
As genome-wide association efforts, such as CARDIoGRAM and METASTROKE, are ongoing to reveal susceptibility loci for their underlying disease—atherosclerotic disease—identification of candidate genes explaining the associations of these loci has proven the main challenge. Many disease susceptibility loci colocalize with DNA regulatory elements, which influence gene expression through chromatin interactions. Therefore, the target genes of these regulatory elements can be considered candidate genes. Applying these biological principles, we used an alternative approach to annotate susceptibility loci and identify candidate genes for human atherosclerotic disease based on circular chromosome conformation capture followed by sequencing.
Methods and Results—
In human monocytes and coronary endothelial cells, we generated 63 chromatin interaction data sets for 37 active DNA regulatory elements that colocalize with known susceptibility loci for coronary artery disease (CARDIoGRAMplusC4D) and large artery stroke (METASTROKE). By circular chromosome conformation capture followed by sequencing, we identified a physical 3-dimensional interaction with 326 candidate genes expressed in at least 1 of these cell types, of which 294 have not been reported before. We highlight 16 genes based on expression quantitative trait loci.
Conclusions—
Our findings provide additional candidate-gene annotation for 37 disease susceptibility loci for human atherosclerotic disease that are of potential interest to better understand the complex pathophysiology of cardiovascular diseases.
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Nagano H, Shibano K, Matsumoto Y, Yokota A, Wada M. Isolation and amino acid sequence of a dehydratase acting on d-erythro-3-hydroxyaspartate from Pseudomonas sp. N99, and its application in the production of optically active 3-hydroxyaspartate. Biosci Biotechnol Biochem 2017; 81:1156-1164. [PMID: 28290777 DOI: 10.1080/09168451.2017.1295804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
An enzyme catalyzing the ammonia-lyase reaction for the conversion of d-erythro-3-hydroxyaspartate to oxaloacetate was purified from the cell-free extract of a soil-isolated bacterium Pseudomonas sp. N99. The enzyme exhibited ammonia-lyase activity toward l-threo-3-hydroxyaspartate and d-erythro-3-hydroxyaspartate, but not toward other 3-hydroxyaspartate isomers. The deduced amino acid sequence of the enzyme, which belongs to the serine/threonine dehydratase family, shows similarity to the sequence of l-threo-3-hydroxyaspartate ammonia-lyase (EC 4.3.1.16) from Pseudomonas sp. T62 (74%) and Saccharomyces cerevisiae (64%) and serine racemase from Schizosaccharomyces pombe (65%). These results suggest that the enzyme is similar to l-threo-3-hydroxyaspartate ammonia-lyase from Pseudomonas sp. T62, which does not act on d-erythro-3-hydroxyaspartate. We also then used the recombinant enzyme expressed in Escherichia coli to produce optically pure l-erythro-3-hydroxyaspartate and d-threo-3-hydroxyaspartate from the corresponding dl-racemic mixtures. The enzymatic resolution reported here is one of the simplest and the first enzymatic method that can be used for obtaining optically pure l-erythro-3-hydroxyaspartate.
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Affiliation(s)
- Hiroyuki Nagano
- a Laboratory of Microbial Physiology, Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan
| | - Kana Shibano
- a Laboratory of Microbial Physiology, Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan
| | - Yu Matsumoto
- a Laboratory of Microbial Physiology, Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan
| | - Atsushi Yokota
- a Laboratory of Microbial Physiology, Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan
| | - Masaru Wada
- a Laboratory of Microbial Physiology, Research Faculty of Agriculture , Hokkaido University , Sapporo , Japan
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Chen Z, Huang W, Srinivas SR, Jones CR, Ganapathy V, Prasad PD. Serine Racemase and D-Serine Transport in Human Placenta and Evidence for a Transplacental Gradient for D-Serine in Humans. ACTA ACUST UNITED AC 2016; 11:294-303. [PMID: 15219883 DOI: 10.1016/j.jsgi.2004.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To investigate the possible role of human placenta in providing D-serine to the developing fetus. METHODS Expression of serine racemase in placenta was determined by reverse transcriptase polymerase chain reaction and northern analysis and confirmed by subsequent cloning. The transport of D-serine by human ATB(0) was characterized by expressing the cloned cDNA transiently in mammalian cells using the vaccinia virus expression system. D-serine levels in maternal and fetal blood were measured by fluorescence high-performance liquid chromatography (HPLC) after derivatization of the amino acids with o-phthaldialdehyde and N-tertiary-butyloxycarbonyl-L-cysteine. RESULTS mRNA for serine racemase was detected in placenta. ATB(0) was capable of d-serine transport, and the transport process is obligatorily dependent on sodium (Na+) with a Na(+):substrate stoichiometry of 1:1 and saturable with a Michaelis-Menten constant of 310 +/- 30 microM. Furthermore, studies have shown that ATB(0) is not expressed in the maternal-facing brush border membrane of human placental syncytiotrophoblast. The circulating concentration of D-serine in maternal serum is 5.8 +/- 0.5 microM, and the corresponding value in the fetal serum is 14.6 +/- 1.2 microM, indicating a two- to three-fold higher concentration of D-serine in the fetus than in the mother. CONCLUSION We speculate that D-serine is synthesized in human placenta by the racemization of L-serine and that ATB(0), expressed on the basal membrane of the syncytiotrophoblast, mediates the efflux of D-serine into the fetal circulation in exchange for other amino acids in fetal blood.
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Affiliation(s)
- Zhong Chen
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, 1120 Laney Walker Boulevard, Augusta, GA 30912-2100, USA
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Abstract
Homochirality is fundamental for life. L-Amino acids are exclusively used as substrates for the polymerization and formation of peptides and proteins in living systems. However, D- amino acids were recently detected in various living organisms, including mammals. Of these D-amino acids, D-serine has been most extensively studied. D-Serine was found to play an important role as a neurotransmitter in the human central nervous system (CNS) by binding to the N-methyl- D-aspartate receptor (NMDAr). D-Serine binds with high affinity to a co-agonist site at the NMDAr and, along with glutamate, mediates several vital physiological and pathological processes, including NMDAr transmission, synaptic plasticity and neurotoxicity. Therefore, a key role for D-serine as a determinant of NMDAr mediated neurotransmission in mammalian CNS has been suggested. In this context, we review the known functions of D-serine in human physiology, such as CNS development, and pathology, such as neuro-psychiatric and neurodegenerative diseases related to NMDAr dysfunction.
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The NMDA Receptor and Schizophrenia: From Pathophysiology to Treatment. ADVANCES IN PHARMACOLOGY 2016; 76:351-82. [PMID: 27288082 DOI: 10.1016/bs.apha.2016.01.006] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Schizophrenia is a severe mental illness that affects almost 1% of the population worldwide. Even though the etiology of schizophrenia is uncertain, it is believed to be a neurodevelopmental disorder that results from a combination of environmental insults and genetic vulnerabilities. Over the past 20 years, there has been a confluence of evidence from many research disciplines pointing to alterations in excitatory signaling, particularly involving hypofunction of the N-methyl-d-aspartate receptor (NMDAR), as a key contributor to the schizophrenia disease process. This review describes the structure-function relationship of the NMDAR channel and how the glycine modulatory site acts as an important regulator of its activity. In addition, this review highlights the genetic, pharmacologic, and biochemical evidence supporting the hypothesis that NMDAR hypofunction contributes to the pathophysiology of schizophrenia. Finally, this chapter highlights some of the most recent and promising pharmacological strategies that are designed to either, directly or indirectly, augment NMDAR function in an effort to treat the cognitive and negative symptoms of schizophrenia that are not helped by currently available medications.
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Katane M, Kaneko Y, Watanabe M, Doi Y, Tanaka T, Kasuga Y, Yoshida N, Kumakubo S, Nakayama K, Matsuda S, Furuchi T, Saitoh Y, Sekine M, Koyama N, Tomoda H, Homma H. Identification and characterization of natural microbial products that alter the free d-aspartate content of mammalian cells. Bioorg Med Chem Lett 2016; 26:556-560. [PMID: 26642769 DOI: 10.1016/j.bmcl.2015.11.073] [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: 08/31/2015] [Revised: 11/13/2015] [Accepted: 11/20/2015] [Indexed: 11/17/2022]
Abstract
Mammalian cells possess the molecular apparatus necessary to take up, degrade, synthesize, and release free d-aspartate, which plays an important role in physiological functions within the body. Here, biologically active microbial compounds and pre-existing drugs were screened for their ability to alter the intracellular d-aspartate level in mammalian cells, and several candidate compounds were identified. Detailed analytical studies suggested that two of these compounds, mithramycin A and geldanamycin, suppress the biosynthesis of d-aspartate in cells. Further studies suggested that these compounds act at distinct sites within the cell. These compounds may advance our current understanding of biosynthesis of d-aspartate in mammals, a whole picture of which remains to be disclosed.
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Affiliation(s)
- Masumi Katane
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yuusuke Kaneko
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Misaki Watanabe
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yuki Doi
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Taku Tanaka
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yukino Kasuga
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Natsumi Yoshida
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Saeka Kumakubo
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Kazuki Nakayama
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Satsuki Matsuda
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Takemitsu Furuchi
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yasuaki Saitoh
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Masae Sekine
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Nobuhiro Koyama
- Laboratory of Microbial Chemistry, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Hiroshi Tomoda
- Laboratory of Microbial Chemistry, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Hiroshi Homma
- Laboratory of Biomolecular Science, Graduate School of Pharmaceutical and Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
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Kiriyama Y, Nochi H. D-Amino Acids in the Nervous and Endocrine Systems. SCIENTIFICA 2016; 2016:6494621. [PMID: 28053803 PMCID: PMC5178360 DOI: 10.1155/2016/6494621] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/14/2016] [Indexed: 05/12/2023]
Abstract
Amino acids are important components for peptides and proteins and act as signal transmitters. Only L-amino acids have been considered necessary in mammals, including humans. However, diverse D-amino acids, such as D-serine, D-aspartate, D-alanine, and D-cysteine, are found in mammals. Physiological roles of these D-amino acids not only in the nervous system but also in the endocrine system are being gradually revealed. N-Methyl-D-aspartate (NMDA) receptors are associated with learning and memory. D-Serine, D-aspartate, and D-alanine can all bind to NMDA receptors. H2S generated from D-cysteine reduces disulfide bonds in receptors and potentiates their activity. Aberrant receptor activity is related to diseases of the central nervous system (CNS), such as Alzheimer's disease, amyotrophic lateral sclerosis, and schizophrenia. Furthermore, D-amino acids are detected in parts of the endocrine system, such as the pineal gland, hypothalamus, pituitary gland, pancreas, adrenal gland, and testis. D-Aspartate is being investigated for the regulation of hormone release from various endocrine organs. Here we focused on recent findings regarding the synthesis and physiological functions of D-amino acids in the nervous and endocrine systems.
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Affiliation(s)
- Yoshimitsu Kiriyama
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Shido 1314-1, Sanuki, Kagawa 769-2193, Japan
| | - Hiromi Nochi
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Shido 1314-1, Sanuki, Kagawa 769-2193, Japan
- *Hiromi Nochi:
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Katane M, Nakayama K, Kawata T, Yokoyama Y, Matsui Y, Kaneko Y, Matsuda S, Saitoh Y, Miyamoto T, Sekine M, Homma H. A sensitive assay for measuring aspartate-specific amino acid racemase activity. J Pharm Biomed Anal 2015; 116:109-15. [DOI: 10.1016/j.jpba.2014.12.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/18/2014] [Accepted: 12/21/2014] [Indexed: 11/16/2022]
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Genome-wide association study of NMDA receptor coagonists in human cerebrospinal fluid and plasma. Mol Psychiatry 2015; 20:1557-64. [PMID: 25666758 DOI: 10.1038/mp.2014.190] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 11/05/2014] [Accepted: 12/08/2014] [Indexed: 01/13/2023]
Abstract
The N-methyl-D-aspartate receptor (NMDAR) coagonists glycine, D-serine and L-proline play crucial roles in NMDAR-dependent neurotransmission and are associated with a range of neuropsychiatric disorders. We conducted the first genome-wide association study of concentrations of these coagonists and their enantiomers in plasma and cerebrospinal fluid (CSF) of human subjects from the general population (N=414). Genetic variants at chromosome 22q11.2, located in and near PRODH (proline dehydrogenase), were associated with L-proline in plasma (β=0.29; P=6.38 × 10(-10)). The missense variant rs17279437 in the proline transporter SLC6A20 was associated with L-proline in CSF (β=0.28; P=9.68 × 10(-9)). Suggestive evidence of association was found for the D-serine plasma-CSF ratio at the D-amino-acid oxidase (DAO) gene (β=-0.28; P=9.08 × 10(-8)), whereas a variant in SRR (that encodes serine racemase and is associated with schizophrenia) constituted the most strongly associated locus for the L-serine to D-serine ratio in CSF. All these genes are highly expressed in rodent meninges and choroid plexus, anatomical regions relevant to CSF physiology. The enzymes and transporters they encode may be targeted to further construe the nature of NMDAR coagonist involvement in NMDAR gating. Furthermore, the highlighted genetic variants may be followed up in clinical populations, for example, schizophrenia and 22q11 deletion syndrome. Overall, this targeted metabolomics approach furthers the understanding of NMDAR coagonist concentration variability and sets the stage for non-targeted CSF metabolomics projects.
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Kolodney G, Dumin E, Safory H, Rosenberg D, Mori H, Radzishevsky I, Radzishevisky I, Wolosker H. Nuclear Compartmentalization of Serine Racemase Regulates D-Serine Production: IMPLICATIONS FOR N-METHYL-D-ASPARTATE (NMDA) RECEPTOR ACTIVATION. J Biol Chem 2015; 290:31037-50. [PMID: 26553873 DOI: 10.1074/jbc.m115.699496] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Indexed: 11/06/2022] Open
Abstract
D-Serine is a physiological co-agonist that activates N-methyl D-aspartate receptors (NMDARs) and is essential for neurotransmission, synaptic plasticity, and behavior. D-Serine may also trigger NMDAR-mediated neurotoxicity, and its dysregulation may play a role in neurodegeneration. D-Serine is synthesized by the enzyme serine racemase (SR), which directly converts L-serine to D-serine. However, many aspects concerning the regulation of D-serine production under physiological and pathological conditions remain to be elucidated. Here, we investigate possible mechanisms regulating the synthesis of D-serine by SR in paradigms relevant to neurotoxicity. We report that SR undergoes nucleocytoplasmic shuttling and that this process is dysregulated by several insults leading to neuronal death, typically by apoptotic stimuli. Cell death induction promotes nuclear accumulation of SR, in parallel with the nuclear translocation of GAPDH and Siah proteins at an early stage of the cell death process. Mutations in putative SR nuclear export signals (NESs) elicit SR nuclear accumulation and its depletion from the cytosol. Following apoptotic insult, SR associates with nuclear GAPDH along with other nuclear components, and this is accompanied by complete inactivation of the enzyme. As a result, extracellular D-serine concentration is reduced, even though extracellular glutamate concentration increases severalfold. Our observations imply that nuclear translocation of SR provides a fail-safe mechanism to prevent or limit secondary NMDAR-mediated toxicity in nearby synapses.
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Affiliation(s)
- Goren Kolodney
- From the Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology and
| | - Elena Dumin
- the Laboratory of Clinical Biochemistry, Metabolic Unit, Rambam Health Care Campus, Haifa 31096, Israel, and
| | - Hazem Safory
- From the Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology and
| | - Dina Rosenberg
- From the Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology and
| | - Hisashi Mori
- the Department of Molecular Neuroscience, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan
| | - Inna Radzishevsky
- From the Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology and
| | | | - Herman Wolosker
- From the Department of Biochemistry, Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology and
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Kubota T, Shimamura S, Kobayashi T, Nunoura T, Deguchi S. Distribution of eukaryotic serine racemases in the bacterial domain and characterization of a representative protein in Roseobacter litoralis Och 149. MICROBIOLOGY-SGM 2015; 162:53-61. [PMID: 26475231 DOI: 10.1099/mic.0.000200] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Two distinct bacterial and eukaryotic serine racemases (SRs) have been identified based on phylogenetic and biochemical characteristics. Although some reports have suggested that marine heterotrophic bacteria have the potential to produce d-serine, the gene encoding bacterial SRs is not found in those bacterial genomes. In this study, using in-depth genomic analysis, we found that eukaryotic SR homologues were distributed widely in various bacterial genomes. Additionally, we selected a eukaryotic SR homologue from a marine heterotrophic bacterium, Roseobacter litoralis Och 149 (RiSR), and constructed an RiSR gene expression system in Escherichia coli for studying the properties of the enzyme. Among the tested amino acids, the recombinant RiSR exhibited both racemization and dehydration activities only towards serine, similar to many eukaryotic SRs. Mg2+ and MgATP enhanced both activities of RiSR, whereas EDTA abolished these enzymatic activities. The enzymatic properties and domain structure of RiSR were similar to those of eukaryotic SRs, particularly mammalian SRs. However, RiSR showed lower catalytic efficiency for L-serine dehydration (kcat/Km=0.094 min(-1) mM(-1)) than those of eukaryotic SRs reported to date (kcat/Km=0.6-21 min(-1) mM(-1)). In contrast, the catalytic efficiency for L-serine racemization of RiSR (kcat/Km=3.14 min(-1) mM(-1)) was 34-fold higher than that of l-serine dehydration. These data suggested that RiSR primarily catalysed serine racemization rather than dehydration.
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Affiliation(s)
- Takaaki Kubota
- Research and Development Center for Marine Biosciences, Marine Functional Biology Group, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan
| | - Shigeru Shimamura
- Research and Development Center for Marine Biosciences, Marine Functional Biology Group, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan
| | - Tohru Kobayashi
- Research and Development Center for Marine Biosciences, Marine Functional Biology Group, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan
| | - Takuro Nunoura
- Research and Development Center for Marine Biosciences, Marine Functional Biology Group, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan
| | - Shigeru Deguchi
- Research and Development Center for Marine Biosciences, Marine Functional Biology Group, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Japan
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Rama Rao KV, Kielian T. Neuron-astrocyte interactions in neurodegenerative diseases: Role of neuroinflammation. ACTA ACUST UNITED AC 2015; 6:245-263. [PMID: 26543505 DOI: 10.1111/cen3.12237] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Selective neuron loss in discrete brain regions is a hallmark of various neurodegenerative disorders, although the mechanisms responsible for this regional vulnerability of neurons remain largely unknown. Earlier studies attributed neuron dysfunction and eventual loss during neurodegenerative diseases as exclusively cell autonomous. Although cell-intrinsic factors are one critical aspect in dictating neuron death, recent evidence also supports the involvement of other central nervous system cell types in propagating non-cell autonomous neuronal injury during neurodegenerative diseases. One such example is astrocytes, which support neuronal and synaptic function, but can also contribute to neuroinflammatory processes through robust chemokine secretion. Indeed, aberrations in astrocyte function have been shown to negatively impact neuronal integrity in several neurological diseases. The present review focuses on neuroinflammatory paradigms influenced by neuron-astrocyte cross-talk in the context of select neurodegenerative diseases.
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Affiliation(s)
- Kakulavarapu V Rama Rao
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Tammy Kielian
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Yamamuro K, Kimoto S, Rosen KM, Kishimoto T, Makinodan M. Potential primary roles of glial cells in the mechanisms of psychiatric disorders. Front Cell Neurosci 2015; 9:154. [PMID: 26029044 PMCID: PMC4432872 DOI: 10.3389/fncel.2015.00154] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Accepted: 04/06/2015] [Indexed: 01/05/2023] Open
Abstract
While neurons have long been considered the major player in multiple brain functions such as perception, emotion, and memory, glial cells have been relegated to a far lesser position, acting as merely a “glue” to support neurons. Multiple lines of recent evidence, however, have revealed that glial cells such as oligodendrocytes, astrocytes, and microglia, substantially impact on neuronal function and activities and are significantly involved in the underlying pathobiology of psychiatric disorders. Indeed, a growing body of evidence indicates that glial cells interact extensively with neurons both chemically (e.g., through neurotransmitters, neurotrophic factors, and cytokines) and physically (e.g., through gap junctions), supporting a role for these cells as likely significant modifiers not only of neural function in brain development but also disease pathobiology. Since questions have lingered as to whether glial dysfunction plays a primary role in the biology of neuropsychiatric disorders or a role related solely to their support of neuronal physiology in these diseases, informative and predictive animal models have been developed over the last decade. In this article, we review recent findings uncovered using glia-specific genetically modified mice with which we can evaluate both the causation of glia dysfunction and its potential role in neuropsychiatric disorders such as autism and schizophrenia.
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Affiliation(s)
- Kazuhiko Yamamuro
- Department of Psychiatry, Faculty of Medicine, Nara Medical University, Kashihara Japan
| | - Sohei Kimoto
- Department of Psychiatry, Faculty of Medicine, Nara Medical University, Kashihara Japan
| | | | - Toshifumi Kishimoto
- Department of Psychiatry, Faculty of Medicine, Nara Medical University, Kashihara Japan
| | - Manabu Makinodan
- Department of Psychiatry, Faculty of Medicine, Nara Medical University, Kashihara Japan
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Glycolytic flux controls D-serine synthesis through glyceraldehyde-3-phosphate dehydrogenase in astrocytes. Proc Natl Acad Sci U S A 2015; 112:E2217-24. [PMID: 25870284 DOI: 10.1073/pnas.1416117112] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
D-Serine is an essential coagonist with glutamate for stimulation of N-methyl-D-aspartate (NMDA) glutamate receptors. Although astrocytic metabolic processes are known to regulate synaptic glutamate levels, mechanisms that control D-serine levels are not well defined. Here we show that d-serine production in astrocytes is modulated by the interaction between the D-serine synthetic enzyme serine racemase (SRR) and a glycolytic enzyme, glyceraldehyde 3-phosphate dehydrogenase (GAPDH). In primary cultured astrocytes, glycolysis activity was negatively correlated with D-serine level. We show that SRR interacts directly with GAPDH, and that activation of glycolysis augments this interaction. Biochemical assays using mutant forms of GAPDH with either reduced activity or reduced affinity to SRR revealed that GAPDH suppresses SRR activity by direct binding to GAPDH and through NADH, a product of GAPDH. NADH allosterically inhibits the activity of SRR by promoting the disassociation of ATP from SRR. Thus, astrocytic production of D-serine is modulated by glycolytic activity via interactions between GAPDH and SRR. We found that SRR is expressed in astrocytes in the subiculum of the human hippocampus, where neurons are known to be particularly vulnerable to loss of energy. Collectively, our findings suggest that astrocytic energy metabolism controls D-serine production, thereby influencing glutamatergic neurotransmission in the hippocampus.
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Biosynthesis of D-aspartate in mammals: the rat and human homologs of mouse aspartate racemase are not responsible for the biosynthesis of D-aspartate. Amino Acids 2015; 47:975-85. [PMID: 25646960 DOI: 10.1007/s00726-015-1926-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 01/21/2015] [Indexed: 12/23/2022]
Abstract
D-Aspartate (D-Asp) has important physiological functions, and recent studies have shown that substantial amounts of free D-Asp are present in a wide variety of mammalian tissues and cells. Biosynthesis of D-Asp has been observed in several cultured rat cell lines, and a murine gene (glutamate-oxaloacetate transaminase 1-like 1, Got1l1) that encodes Asp racemase, a synthetic enzyme that produces D-Asp from L-Asp, was proposed recently. The product of this gene is homologous to mammalian glutamate-oxaloacetate transaminase (GOT). Here, we tested the hypothesis that rat and human homologs of mouse GOT1L1 are involved in Asp synthesis. The following two approaches were applied, since the numbers of attempts were unsuccessful to prepare soluble GOT1L1 recombinant proteins. First, the relationship between the D-Asp content and the expression levels of the mRNAs encoding GOT1L1 and D-Asp oxidase, a primary degradative enzyme of D-Asp, was examined in several rat and human cell lines. Second, the effect of knockdown of the Got1l1 gene on D-Asp biosynthesis during culture of the cells was determined. The results presented here suggest that the rat and human homologs of mouse GOT1L1 are not involved in D-Asp biosynthesis. Therefore, D-Asp biosynthetic pathway in mammals is still an urgent issue to be resolved.
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Jun DY, Taub D, Chrest FJ, Kim YH. Requirement of the expression of 3-phosphoglycerate dehydrogenase for traversing S phase in murine T lymphocytes following immobilized anti-CD3 activation. Cell Immunol 2013; 287:78-85. [PMID: 24434753 DOI: 10.1016/j.cellimm.2013.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Revised: 10/29/2013] [Accepted: 12/05/2013] [Indexed: 11/25/2022]
Abstract
Murine resting (G(0)) T lymphocytes contained no detectable mRNA of 3-phosphoglycerate dehydrogenase (PHGDH) catalyzing the first step in the phosphorylated pathway of l-serine biosynthesis. Immobilized anti-CD3 activation of G(0) T cells expressed the PHGDH mRNA in G(1) with a maximum level in S phase. G(0) T cells activated with either immobilized anti-CD3 plus CsA or PBu(2), which failed to drive the activated T cells to enter S phase, did not express the PHGDH mRNA unless exogenous rIL-2 was added. Blocking of IL-2R signaling by adding anti-IL-2 and anti-IL-2Rα resulted in no expression of the PHGDH mRNA during immobilized anti-CD3 activation of G(0) T cells. Deprivation of l-serine from culture medium or addition of antisense PHGDH oligonucleotide significantly reduced [(3)H]TdR incorporation of activated T cells. These results indicate that the PHGDH gene expression, dictated by IL-2R signaling, is a crucial event for DNA synthesis during S phase of activated T cells.
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Affiliation(s)
- Do Youn Jun
- Laboratory of Immunobiology, School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Dennis Taub
- Laboratory of Immunology, Gerontology Research Center, NIA, NIH, Baltimore, MD 21224, USA
| | - Francis J Chrest
- Laboratory of Immunology, Gerontology Research Center, NIA, NIH, Baltimore, MD 21224, USA
| | - Young Ho Kim
- Laboratory of Immunobiology, School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea.
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Otte DM, Barcena de Arellano ML, Bilkei-Gorzo A, Albayram Ö, Imbeault S, Jeung H, Alferink J, Zimmer A. Effects of Chronic D-Serine Elevation on Animal Models of Depression and Anxiety-Related Behavior. PLoS One 2013; 8:e67131. [PMID: 23805296 PMCID: PMC3689701 DOI: 10.1371/journal.pone.0067131] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 05/15/2013] [Indexed: 12/17/2022] Open
Abstract
NMDA receptors are activated after binding of the agonist glutamate to the NR2 subunit along with a co-agonist, either L-glycine or D-serine, to the NR1 subunit. There is substantial evidence to suggest that D-serine is the most relevant co-agonist in forebrain regions and that alterations in D-serine levels contribute to psychiatric disorders. D-serine is produced through isomerization of L-serine by serine racemase (Srr), either in neurons or in astrocytes. It is released by astrocytes by an activity-dependent mechanism involving secretory vesicles. In the present study we generated transgenic mice (SrrTg) expressing serine racemase under a human GFAP promoter. These mice were biochemically and behaviorally analyzed using paradigms of anxiety, depression and cognition. Furthermore, we investigated the behavioral effects of long-term administration of D-serine added to the drinking water. Elevated brain D-serine levels in SrrTg mice resulted in specific behavioral phenotypes in the forced swim, novelty suppression of feeding and olfactory bulbectomy paradigms that are indicative of a reduced proneness towards depression-related behavior. Chronic dietary D-serine supplement mimics the depression-related behavioral phenotype observed in SrrTg mice. Our results suggest that D-serine supplementation may improve mood disorders.
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Affiliation(s)
- David-Marian Otte
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany
| | | | | | - Önder Albayram
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany
| | - Sophie Imbeault
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany
| | - Haang Jeung
- Department of Psychiatry, University of Bonn, Bonn, Germany
| | - Judith Alferink
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany
- Department of Psychiatry, University of Bonn, Bonn, Germany
| | - Andreas Zimmer
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany
- * E-mail:
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Paula-Lima AC, Brito-Moreira J, Ferreira ST. Deregulation of excitatory neurotransmission underlying synapse failure in Alzheimer's disease. J Neurochem 2013; 126:191-202. [PMID: 23668663 DOI: 10.1111/jnc.12304] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 05/09/2013] [Accepted: 05/10/2013] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia in the elderly. Memory loss in AD is increasingly attributed to soluble oligomers of the amyloid-β peptide (AβOs), toxins that accumulate in AD brains and target particular synapses. Glutamate receptors appear to be centrally involved in synaptic targeting by AβOs. Once bound to neurons, AβOs dysregulate the activity and reduce the surface expression of both N-methyl-D-aspartate (NMDA) and 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propanoic acid (AMPA) types of glutamate receptors, impairing signaling pathways involved in synaptic plasticity. In the extracellular milieu, AβOs promote accumulation of the excitatory amino acids, glutamate and D-serine. This leads to overactivation of glutamate receptors, triggering abnormal calcium signals with noxious impacts on neurons. Here, we review key findings linking AβOs to deregulated glutamate neurotransmission and implicating this as a primary mechanism of synapse failure in AD. We also discuss strategies to counteract the impact of AβOs on excitatory neurotransmission. In particular, we review evidence showing that inducing neuronal hyperpolarization via activation of inhibitory GABA(A) receptors prevents AβO-induced excitotoxicity, suggesting that this could comprise a possible therapeutic approach in AD.
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Affiliation(s)
- Andrea C Paula-Lima
- Department of Basic Sciences, Faculty of Dentistry, University of Chile, Santiago, Chile.
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Ma T, Abazyan S, Abazyan B, Nomura J, Yang C, Seshadri S, Sawa A, Snyder S, Pletnikov M. Pathogenic disruption of DISC1-serine racemase binding elicits schizophrenia-like behavior via D-serine depletion. Mol Psychiatry 2013; 18:557-67. [PMID: 22801410 PMCID: PMC3475769 DOI: 10.1038/mp.2012.97] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Perturbation of Disrupted-In-Schizophrenia-1 (DISC1) and D-serine/NMDA receptor hypofunction have both been implicated in the pathophysiology of schizophrenia and other psychiatric disorders. In the present study, we demonstrate that these two pathways intersect with behavioral consequences. DISC1 binds to and stabilizes serine racemase (SR), the enzyme that generates D-serine, an endogenous co-agonist of the NMDA receptor. Mutant DISC1 fails to bind to SR, facilitating ubiquitination and degradation of SR and a decrease in D-serine production. To elucidate DISC1-SR interactions in vivo, we generated a mouse model of selective and inducible expression of mutant DISC1 in astrocytes, the main source of D-serine in the brain. Expression of mutant DISC1 downregulates endogenous DISC1 and decreases protein but not mRNA levels of SR, resulting in diminished production of D-serine. In contrast, mutant DISC1 does not alter levels of ALDH1L1, connexins, GLT-1 or binding partners of DISC1 and SR, LIS1 or PICK1. Adult male and female mice with lifelong expression of mutant DISC1 exhibit behavioral abnormalities consistent with hypofunction of NMDA neurotransmission. Specifically, mutant mice display greater responses to an NMDA antagonist, MK-801, in open field and pre-pulse inhibition of the acoustic startle tests and are significantly more sensitive to the ameliorative effects of D-serine. These findings support a model wherein mutant DISC1 leads to SR degradation via dominant negative effects, resulting in D-serine deficiency that diminishes NMDA neurotransmission thus linking DISC1 and NMDA pathophysiological mechanisms in mental illness.
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Affiliation(s)
- T.M. Ma
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD
| | - S. Abazyan
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - B. Abazyan
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - J. Nomura
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD,Division of Molecular Medical Science, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan
| | - C. Yang
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - S. Seshadri
- Division of Molecular Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD
| | - A. Sawa
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD,Division of Molecular Psychiatry, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - S.H. Snyder
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD,Departments of Pharmacology and Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD,co-corresponding authors
| | - M.V. Pletnikov
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD,The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD,Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD,co-corresponding authors
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Calcia MA, Madeira C, Alheira FV, Silva TCS, Tannos FM, Vargas-Lopes C, Goldenstein N, Brasil MA, Ferreira ST, Panizzutti R. Plasma levels of D-serine in Brazilian individuals with schizophrenia. Schizophr Res 2012; 142:83-7. [PMID: 23063707 DOI: 10.1016/j.schres.2012.09.014] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 09/08/2012] [Accepted: 09/17/2012] [Indexed: 01/08/2023]
Abstract
Changes in D-serine availability in the brain may contribute to the hypofunction of NMDA-glutamate receptors in schizophrenia; however, measurements of blood levels of D-serine in individuals with schizophrenia have not been consistent amongst previous studies. Here we studied plasma levels of D-serine and L-serine in 84 Brazilian individuals with schizophrenia and 75 gender- and age-matched controls. Plasma levels of D-serine and the ratio of plasma D-serine to total serine were significantly lower in individuals with schizophrenia as compared to the control group. Levels of D-serine were significantly and negatively correlated to the severity of negative symptoms of schizophrenia. We also observed that plasma levels of D-serine significantly decreased with aging in healthy controls. Our results suggest that the possible role of D-serine in the pathophysiology of schizophrenia should be further investigated, with possible implications for the drug treatment of this disorder.
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Affiliation(s)
- Marilia A Calcia
- Serviço de Psiquiatria e Psicologia Médica, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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43
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Wolosker H, Mori H. Serine racemase: an unconventional enzyme for an unconventional transmitter. Amino Acids 2012; 43:1895-904. [PMID: 22847782 DOI: 10.1007/s00726-012-1370-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Accepted: 07/14/2012] [Indexed: 12/19/2022]
Abstract
The discovery of large amounts of D-serine in the brain challenged the dogma that only L-amino acids are relevant for eukaryotes. The levels of D-serine in the brain are higher than many L-amino acids and account for as much as one-third of L-serine levels. Several studies in the last decades have demonstrated a role of D-serine as an endogenous agonist of N-methyl-D-aspartate receptors (NMDARs). D-Serine is required for NMDAR activity during normal neurotransmission as well as NMDAR overactivation that takes place in neurodegenerative conditions. Still, there are many unanswered questions about D-serine neurobiology, including regulation of its synthesis, release and metabolism. Here, we review the mechanisms of D-serine synthesis by serine racemase and discuss the lessons we can learn from serine racemase knockout mice, focusing on the roles attributed to D-serine and its cellular origin.
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Affiliation(s)
- Herman Wolosker
- Department of Biochemistry, B. Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, 31096, Haifa, Israel.
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Wang W, Barger SW. Cross-linking of serine racemase dimer by reactive oxygen species and reactive nitrogen species. J Neurosci Res 2012; 90:1218-29. [PMID: 22354542 PMCID: PMC3323679 DOI: 10.1002/jnr.22832] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 10/06/2011] [Accepted: 10/23/2011] [Indexed: 11/11/2022]
Abstract
Serine racemase (SR) is the only identified enzyme in mammals responsible for isomerization of L-serine to D-serine, a coagonist at N-methyl-D-aspartate (NMDA) receptors in the forebrain. Our previous data showed that an apparent SR dimer resistant to sodium dodecyl sulfate and β-mercaptoethanol was elevated in microglial cells after proinflammatory activation. Because the activation of microglia is typically associated with an oxidative burst, oxidative cross-linking between SR subunits was speculated. In this study, an siRNA technique was employed to confirm the identity of this SR dimer band. The oxidative species potentially responsible for the cross-linking was investigated with recombinant SR protein. The data indicate that nitric oxide, peroxynitrite, and hydroxyl radical were the likely candidates, whereas superoxide and hydrogen peroxide per se failed to contribute. Furthermore, the mechanism of formation of SR dimer by peroxynitrite oxidation was studied by mass spectrometry. A disulfide bond between Cys₆ and Cys₁₁₃ was identified in 3-morpholinosydnonimine hydrochloride (SIN-1)-treated SR monomer and dimer. Activity assays indicated that SIN-1 treatment decreased SR activity, confirming our previous conclusion that noncovalent dimer is the most active form of SR. These findings suggest a compensatory feedback in which the consequences of neuroinflammation might dampen D-serine production to limit excitotoxic stimulation of NMDA receptors.
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Affiliation(s)
- Wei Wang
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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Baumgart F, Aicart-Ramos C, Rodriguez-Crespo I. Preparation and assay of recombinant serine racemase. Methods Mol Biol 2012; 794:357-366. [PMID: 21956576 DOI: 10.1007/978-1-61779-331-8_24] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Serine racemase is a glial and neuronal enzyme that reversibly converts L-serine to D-serine, an endogenous co-agonist of N-methyl-D-aspartate receptor type glutamate receptors (NMDARs). Here we present methods to recombinantly express and purify serine racemase in bacteria and two complementary ways to determine D-serine levels in unknown samples. Furthermore, a detailed protocol of serine racemase activity assays is described that can be used to screen for activators and inhibitors in vitro.
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Affiliation(s)
- Florian Baumgart
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas, Universidad Complutense, Madrid, Spain
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Abstract
D-Amino acids play important physiological roles in the mammalian body. Recent investigations revealed that, in mammals, D-amino acids are synthesized from their corresponding L-enantiomers via amino acid racemase. This article describes a method used to measure amino acid racemase activity by high-performance liquid chromatography (HPLC). The assay involves fluorogenic chiral derivatization of amino acids with a newly developed reagent, and enantioseparation of D- and L-amino acid derivatives by HPLC. The method is accurate and reliable, and can be automated using a programmable autosampling injector.
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Affiliation(s)
- Masumi Katane
- Department of Pharmaceutical Life Sciences, Kitasato University, Minatoku, Tokyo, Japan
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Roles of quaternary structure and cysteine residues in the activity of human serine racemase. BMC BIOCHEMISTRY 2011; 12:63. [PMID: 22151352 PMCID: PMC3252284 DOI: 10.1186/1471-2091-12-63] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 12/08/2011] [Indexed: 11/11/2022]
Abstract
Background D-serine is an important coagonist at the NR1 subunit of the NMDA receptor class of glutamate receptors. It is chiefly synthesized in the CNS by serine racemase (SR). Regulation of SR activity is still poorly understood. As step toward developing reagents and methods for investigating SR in vitro, we analyzed structure-function relationships of a recombinant enzyme of human sequence. Results Michaelis-Menten kinetic analysis indicated a KM value of 14 mM and Vmax value of 3.66 μmol·mg-1·hr-1 when L-serine was used as a substrate for purified SR. Gel-filtration chromatography and protein cross-linking experiments revealed that dimer is the major oligomeric form of recombinant SR in aqueous solution, though the proportions of monomer, tetramer, and larger aggregates differed somewhat with the specific buffer used. These buffers also altered activity in a manner correlating with the relative abundance of dimer. Activity assays showed that the dimeric gel-filtration fraction held the highest activity. Chemical reduction with DTT increased the activity of SR by elevating Vmax; cystamine, a reagent that blocks sulfhydryl groups, abolished SR activity. Gel-filtration chromatography and western blot analysis indicated that DTT enhanced the recovery of noncovalent SR dimer. Conclusions These data suggest that SR is most active as a noncovalent dimer containing one or more free sulfhydryls in the enzyme's active center or a modulatory site. Buffer composition and reduction/oxidation status during preparation can dramatically impact interpretations of SR activity. These findings also highlight the possibility that SR is sensitive to oxidative stress in vivo.
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Controlling reaction specificity in pyridoxal phosphate enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1814:1407-18. [PMID: 21664990 DOI: 10.1016/j.bbapap.2011.05.019] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 05/18/2011] [Accepted: 05/25/2011] [Indexed: 11/20/2022]
Abstract
Pyridoxal 5'-phosphate enzymes are ubiquitous in the nitrogen metabolism of all organisms. They catalyze a wide variety of reactions including racemization, transamination, decarboxylation, elimination, retro-aldol cleavage, Claisen condensation, and others on substrates containing an amino group, most commonly α-amino acids. The wide variety of reactions catalyzed by PLP enzymes is enabled by the ability of the covalent aldimine intermediate formed between substrate and PLP to stabilize carbanionic intermediates at Cα of the substrate. This review attempts to summarize the mechanisms by which reaction specificity can be achieved in PLP enzymes by focusing on three aspects of these reactions: stereoelectronic effects, protonation state of the external aldimine intermediate, and interaction of the carbanionic intermediate with the protein side chains present in the active site. This article is part of a Special Issue entitled: Pyridoxal Phosphate Enzymology.
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Katane M, Homma H. D-Aspartate--an important bioactive substance in mammals: a review from an analytical and biological point of view. J Chromatogr B Analyt Technol Biomed Life Sci 2011; 879:3108-21. [PMID: 21524944 DOI: 10.1016/j.jchromb.2011.03.062] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 03/23/2011] [Accepted: 03/30/2011] [Indexed: 01/08/2023]
Abstract
It was long believed that D-amino acids were either unnatural isomers or laboratorial artifacts and that the important functions of amino acids were exerted only by l-amino acids. However, recent investigations have shown that a variety of D-amino acids are present in mammals and that they play important roles in physiological functions in the body. Among the free d-amino acids that have been identified in mammals, D-aspartate (D-Asp) has been shown to play a crucial role in the neuroendocrine and endocrine systems as well as in the central nervous system. Here, we present an overview of recent studies of free D-Asp, focusing on the analytical methods in real biological matrices, expression and localization in tissues and cells, biological and physiological activities, biosynthesis, degradation, cellular transport, and possible relevance to disease. In addition to frequently used techniques for the enantiomeric determination of amino acids, including high-performance liquid chromatography and enzymatic methods, the recent development of analytical methods is also described.
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Affiliation(s)
- Masumi Katane
- Laboratory of Biomolecular Science, Department of Pharmaceutical Life Sciences, Kitasato University, 5-9-1 Shirokane, Tokyo 108-8641, Japan
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Bruno A, Amori L, Costantino G. Addressing the Conformational Flexibility of Serine Racemase by Combining Targeted Molecular Dynamics, Conformational Sampling and Docking Studies. Mol Inform 2011; 30:317-28. [DOI: 10.1002/minf.201000162] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 12/22/2010] [Indexed: 11/06/2022]
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