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Kruyer A, Kalivas PW, Scofield MD. Astrocyte regulation of synaptic signaling in psychiatric disorders. Neuropsychopharmacology 2023; 48:21-36. [PMID: 35577914 PMCID: PMC9700696 DOI: 10.1038/s41386-022-01338-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/27/2022] [Accepted: 05/01/2022] [Indexed: 02/07/2023]
Abstract
Over the last 15 years, the field of neuroscience has evolved toward recognizing the critical role of astroglia in shaping neuronal synaptic activity and along with the pre- and postsynapse is now considered an equal partner in tripartite synaptic transmission and plasticity. The relative youth of this recognition and a corresponding deficit in reagents and technologies for quantifying and manipulating astroglia relative to neurons continues to hamper advances in understanding tripartite synaptic physiology. Nonetheless, substantial advances have been made and are reviewed herein. We review the role of astroglia in synaptic function and regulation of behavior with an eye on how tripartite synapses figure into brain pathologies underlying behavioral impairments in psychiatric disorders, both from the perspective of measures in postmortem human brains and more subtle influences on tripartite synaptic regulation of behavior in animal models of psychiatric symptoms. Our goal is to provide the reader a well-referenced state-of-the-art understanding of current knowledge and predict what we may discover with deeper investigation of tripartite synapses using reagents and technologies not yet available.
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Affiliation(s)
- Anna Kruyer
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Peter W Kalivas
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
- Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, USA.
| | - Michael D Scofield
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA.
- Department of Anesthesia & Perioperative Medicine, Medical University of South Carolina, Charleston, SC, USA.
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2
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Zhang H, Lu J, Shang H, Chen J, Lin Z, Liu Y, Wang X, Song L, Jiang X, Jiang H, Shi J, Yan D, Wu S. Alterations of serine racemase expression determine proliferation and differentiation of neuroblastoma cells. FASEB J 2022; 36:e22473. [PMID: 35976172 DOI: 10.1096/fj.202200394rrr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 07/09/2022] [Accepted: 07/18/2022] [Indexed: 11/11/2022]
Abstract
Although the role of serine racemase (SR) in neuropsychiatric disorders has been extensively studied, its role in cell proliferation and differentiation remains unclear. Deletion of Srr, the encoding gene for SR, has been shown to reduce dendritic arborization and dendritic spine density in the brains of adult mice, whereas increased SR levels have been associated with differentiation in cell cultures. Previously, we demonstrated that valproic acid induces differentiation in the N2A neuroblastoma cell line, and that this differentiation is associated with increased SR expression. These observations suggest that SR may have a role in cell proliferation and differentiation. We herein found that both valproic acid and all-trans retinoic acid induced N2A differentiation. In contrast, knockdown of SR reduced levels of differentiation, increased N2A proliferation, promoted cell cycle entry, and modulated expression of cell cycle-related proteins. To further evaluate the effects of SR expression on cell proliferation and differentiation, we used an in vivo model of neuroblastoma in nude mice. N2A cells stably expressing scramble shRNA (Srrwt -N2A) or specific Srr shRNA (Srrkd -N2A) were subcutaneously injected into nude mice. The weights and volumes of Srrwt -N2A-derived tumors were lower than Srrkd -N2A-derived tumors. Furthermore, Srrwt -N2A-derived tumors were significantly mitigated by intraperitoneal injection of valproic acid, whereas Srrkd -N2A-derived tumors were unaffected. Taken together, our findings demonstrate for the first time that alterations in SR expression determine the transition between proliferation and differentiation in neural progenitor cells. Thus, in addition to its well-established roles in neuropsychiatric disorders, our study has highlighted a novel role for SR in cell proliferation and differentiation.
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Affiliation(s)
- He Zhang
- College of Life and Environmental Sciences, Wenzhou University, Wenzhou, P.R. China.,Zhejiang Provincial Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou, P.R. China.,School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Wenzhou, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou Medical University, Wenzhou, P.R. China
| | - Jinfang Lu
- Wenzhou Key Laboratory of Sanitary Microbiology, Key Laboratory of Laboratory Medicine, Ministry of Education, Wenzhou, P.R. China.,School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, P.R. China
| | - Huiping Shang
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Wenzhou, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou Medical University, Wenzhou, P.R. China
| | - Juan Chen
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Wenzhou, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou Medical University, Wenzhou, P.R. China
| | - Zhengxiu Lin
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, P.R. China
| | - Yimei Liu
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Wenzhou, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou Medical University, Wenzhou, P.R. China
| | - Xianwei Wang
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Wenzhou, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou Medical University, Wenzhou, P.R. China
| | - Liping Song
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Wenzhou, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou Medical University, Wenzhou, P.R. China
| | - Xue Jiang
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Wenzhou, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou Medical University, Wenzhou, P.R. China
| | - Haiyan Jiang
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Wenzhou, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou Medical University, Wenzhou, P.R. China
| | - Jiandong Shi
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, P.R. China
| | - Dongsheng Yan
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Wenzhou, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou Medical University, Wenzhou, P.R. China
| | - Shengzhou Wu
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Wenzhou, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou Medical University, Wenzhou, P.R. China
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3
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Wu S, Zhou J, Zhang H, Barger SW. Serine Racemase Expression Differentiates Aging from Alzheimer's Brain. Curr Alzheimer Res 2022; 19:494-502. [PMID: 35929621 DOI: 10.2174/1567205019666220805105106] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 06/27/2022] [Accepted: 06/29/2022] [Indexed: 01/27/2023]
Abstract
Aging is an inevitable process characterized by progressive loss of physiological integrity and increased susceptibility to cancer, diabetes, cardiovascular, and neurodegenerative diseases; aging is the primary risk factor for Alzheimer's disease (AD), the most common cause of dementia. AD is characterized by brain pathology, including extracellular deposition of amyloid aggregation and intracellular accumulation of neurofibrillary tangles composed of hyperphosphorylated tau protein. In addition, losses of synapses and a wide range of neurons are pivotal pathologies in the AD brain. Accumulating evidence demonstrates hypoactivation of hippocampal neural networks in the aging brain, whereas AD-related mild cognitive impairment (AD-MCI) begins with hyperactivation, followed by a diminution of hippocampal activity as AD develops. The biphasic trends of the activity of the hippocampal neural network are consistent with the alteration of N-methyl-D-aspartate receptor (NMDA-R) activity from aging to prodromal (AD-MCI) to mid-/late stage AD. D-serine, a product of racemization catalyzed by serine racemase (SR), is an important co-agonist of the NMDA-R which is involved in synaptic events including neurotransmission, synaptogenesis, long-term potentiation (LTP), development, and excitotoxicity. SR and D-serine are decreased in the hippocampus of the aging brain, correlating with impairment of cognitive function. By contrast, SR is increased in AD brain, which is associated with a greater degree of cognitive dysfunction. Emerging studies suggest that D-serine levels in the brain or in cerebral spinal fluid from AD patients are higher than in age-matched controls, but the results are inconsistent. Very recently, serum D-serine levels in AD were reported to correlate with sex and clinical dementia rating (CDR) stage. This review will discuss alterations of NMDA-R and SR in aging and AD brain, and the mechanisms underlying the differential regulation of SR will be probed. Collectively, we propose that SR may be a molecular switch that distinguishes the effects of aging from those of AD on the brain.
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Affiliation(s)
- Shengzhou Wu
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, State Key Laboratory of Optometry, Wenzhou, Zhejiang 325003, P.R. China
| | - Jing Zhou
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, State Key Laboratory of Optometry, Wenzhou, Zhejiang 325003, P.R. China
| | - He Zhang
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, State Key Laboratory of Optometry, Wenzhou, Zhejiang 325003, P.R. China.,College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang, P.R. China
| | - Steven W Barger
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock AR, USA.,Geriatric Research, Education & Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock AR, USA
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Koulouris CR, Gardiner SE, Harris TK, Elvers KT, Mark Roe S, Gillespie JA, Ward SE, Grubisha O, Nicholls RA, Atack JR, Bax BD. Tyrosine 121 moves revealing a ligandable pocket that couples catalysis to ATP-binding in serine racemase. Commun Biol 2022; 5:346. [PMID: 35410329 PMCID: PMC9001717 DOI: 10.1038/s42003-022-03264-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 03/14/2022] [Indexed: 11/23/2022] Open
Abstract
Human serine racemase (hSR) catalyses racemisation of L-serine to D-serine, the latter of which is a co-agonist of the NMDA subtype of glutamate receptors that are important in synaptic plasticity, learning and memory. In a 'closed' hSR structure containing the allosteric activator ATP, the inhibitor malonate is enclosed between the large and small domains while ATP is distal to the active site, residing at the dimer interface with the Tyr121 hydroxyl group contacting the α-phosphate of ATP. In contrast, in 'open' hSR structures, Tyr121 sits in the core of the small domain with its hydroxyl contacting the key catalytic residue Ser84. The ability to regulate SR activity by flipping Tyr121 from the core of the small domain to the dimer interface appears to have evolved in animals with a CNS. Multiple X-ray crystallographic enzyme-fragment structures show Tyr121 flipped out of its pocket in the core of the small domain. Data suggest that this ligandable pocket could be targeted by molecules that inhibit enzyme activity.
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Affiliation(s)
- Chloe R Koulouris
- Sussex Drug Discovery Centre, University of Sussex, Brighton, BN1 9QG, UK
| | - Sian E Gardiner
- Medicines Discovery Institute, Cardiff University, Cardiff, CF10 3AT, UK
| | - Tessa K Harris
- Medicines Discovery Institute, Cardiff University, Cardiff, CF10 3AT, UK
| | - Karen T Elvers
- Medicines Discovery Institute, Cardiff University, Cardiff, CF10 3AT, UK
| | - S Mark Roe
- Department of Biochemistry and Biomedicine, University of Sussex, Brighton, BN1 9QJ, UK
| | - Jason A Gillespie
- Medicines Discovery Institute, Cardiff University, Cardiff, CF10 3AT, UK
| | - Simon E Ward
- Medicines Discovery Institute, Cardiff University, Cardiff, CF10 3AT, UK
| | - Olivera Grubisha
- Medicines Discovery Institute, Cardiff University, Cardiff, CF10 3AT, UK
| | - Robert A Nicholls
- MRC Laboratory of Molecular Biology, Francis Crick Ave, CB2 0QH, Cambridge, UK
| | - John R Atack
- Medicines Discovery Institute, Cardiff University, Cardiff, CF10 3AT, UK.
| | - Benjamin D Bax
- Medicines Discovery Institute, Cardiff University, Cardiff, CF10 3AT, UK.
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5
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Human iPSC-Derived Glia as a Tool for Neuropsychiatric Research and Drug Development. Int J Mol Sci 2021; 22:ijms221910254. [PMID: 34638595 PMCID: PMC8508580 DOI: 10.3390/ijms221910254] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 12/19/2022] Open
Abstract
Neuropsychiatric disorders such as schizophrenia or autism spectrum disorder represent a leading and growing burden on worldwide mental health. Fundamental lack in understanding the underlying pathobiology compromises efficient drug development despite the immense medical need. So far, antipsychotic drugs reduce symptom severity and enhance quality of life, but there is no cure available. On the molecular level, schizophrenia and autism spectrum disorders correlate with compromised neuronal phenotypes. There is increasing evidence that aberrant neuroinflammatory responses of glial cells account for synaptic pathologies through deregulated communication and reciprocal modulation. Consequently, microglia and astrocytes emerge as central targets for anti-inflammatory treatment to preserve organization and homeostasis of the central nervous system. Studying the impact of neuroinflammation in the context of neuropsychiatric disorders is, however, limited by the lack of relevant human cellular test systems that are able to represent the dynamic cellular processes and molecular changes observed in human tissue. Today, patient-derived induced pluripotent stem cells offer the opportunity to study neuroinflammatory mechanisms in vitro that comprise the genetic background of affected patients. In this review, we summarize the major findings of iPSC-based microglia and astrocyte research in the context of neuropsychiatric diseases and highlight the benefit of 2D and 3D co-culture models for the generation of efficient in vitro models for target screening and drug development.
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Jouroukhin Y, Zhu X, Shevelkin AV, Hasegawa Y, Abazyan B, Saito A, Pevsner J, Kamiya A, Pletnikov MV. Adolescent Δ 9-Tetrahydrocannabinol Exposure and Astrocyte-Specific Genetic Vulnerability Converge on Nuclear Factor-κB-Cyclooxygenase-2 Signaling to Impair Memory in Adulthood. Biol Psychiatry 2019; 85:891-903. [PMID: 30219209 PMCID: PMC6525084 DOI: 10.1016/j.biopsych.2018.07.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/19/2018] [Accepted: 07/30/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND Although several studies have linked adolescent cannabis use to long-term cognitive dysfunction, there are negative reports as well. The fact that not all users develop cognitive impairment suggests a genetic vulnerability to adverse effects of cannabis, which are attributed to action of Δ9-tetrahydrocannabinol (Δ9-THC), a cannabis constituent and partial agonist of brain cannabinoid receptor 1. As both neurons and glial cells express cannabinoid receptor 1, genetic vulnerability could influence Δ9-THC-induced signaling in a cell type-specific manner. METHODS Here we use an animal model of inducible expression of dominant-negative disrupted in schizophrenia 1 (DN-DISC1) selectively in astrocytes to evaluate the molecular mechanisms, whereby an astrocyte genetic vulnerability could interact with adolescent Δ9-THC exposure to impair recognition memory in adulthood. RESULTS Selective expression of DN-DISC1 in astrocytes and adolescent treatment with Δ9-THC synergistically affected recognition memory in adult mice. Similar deficits in recognition memory were observed following knockdown of endogenous Disc1 in hippocampal astrocytes in mice treated with Δ9-THC during adolescence. At the molecular level, DN-DISC1 and Δ9-THC synergistically activated the nuclear factor-κB-cyclooxygenase-2 pathway in astrocytes and decreased immunoreactivity of parvalbumin-positive presynaptic inhibitory boutons around pyramidal neurons of the hippocampal CA3 area. The cognitive abnormalities were prevented in DN-DISC1 mice exposed to Δ9-THC by simultaneous adolescent treatment with the cyclooxygenase-2 inhibitor, NS398. CONCLUSIONS Our data demonstrate that individual vulnerability to cannabis can be exclusively mediated by astrocytes. Results of this work suggest that genetic predisposition within astrocytes can exaggerate Δ9-THC-produced cognitive impairments via convergent inflammatory signaling, suggesting possible targets for preventing adverse effects of cannabis within susceptible individuals.
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Affiliation(s)
- Yan Jouroukhin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Xiaolei Zhu
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Alexey V Shevelkin
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Yuto Hasegawa
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Bagrat Abazyan
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Atsushi Saito
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jonathan Pevsner
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland; Kennedy Krieger Institute, Baltimore, Maryland
| | - Atsushi Kamiya
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland.
| | - Mikhail V Pletnikov
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland.
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7
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Wu M, Liu Y, Zhang H, Lian M, Chen J, Jiang H, Xu Y, Shan G, Wu S. Intravenous injection of l-aspartic acid β-hydroxamate attenuates choroidal neovascularization via anti-VEGF and anti-inflammation. Exp Eye Res 2019; 182:93-100. [DOI: 10.1016/j.exer.2019.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/26/2019] [Accepted: 03/19/2019] [Indexed: 10/27/2022]
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8
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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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9
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Effects on Glial Cell Glycolysis in Schizophrenia: An Advanced Aging Phenotype? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1178:25-38. [DOI: 10.1007/978-3-030-25650-0_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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10
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Neuronal serine racemase associates with Disrupted-In-Schizophrenia-1 and DISC1 agglomerates: Implications for schizophrenia. Neurosci Lett 2018; 692:107-114. [PMID: 30391323 DOI: 10.1016/j.neulet.2018.10.055] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 10/18/2018] [Accepted: 10/29/2018] [Indexed: 12/21/2022]
Abstract
D-Serine, an endogenous coagonist of N-methyl-d-aspartate receptors (NMDARs) at the glycine binding site, is synthesized by serine racemase (SR) through conversion of l-Serine. Dysregulation of SR/D-Serine and Disrupted-In-Schizophrenia-1 (DISC1) contributes to the pathogenesis of schizophrenia at converging pathways, as perturbation of SR-DISC1 binding in astrocytes elicits schizophrenia-like behaviors in mice. However, an association of neuronal SR with DISC1 remains elusive. Here we report that SR associates with DISC1 and its agglomerates in cortical neurons, which can be modulated by NMDAR activity. Endogenous SR colocalizes with DISC1 large agglomerates in the soma and with smaller puncta in the nucleus and dendrites of cortical neurons. Co-immunoprecipitation assays demonstrate SR interaction with DISC1 in cortical neuronal lysates, suggesting the physiological presence of functional SR-DISC1 complexes in neurons. Moreover, exogenous d-Serine application significantly increases the interaction of SR with DISC1, the number of DISC1-SR large agglomerates and the levels of DISC1 agglomerated form along with SR in the triton-insoluble pellet fraction, whereas application of glycine with a glycine transporter inhibitor fails to increase their interactions, abundance of DISC1-SR large agglomerates and levels of DISC1 agglomerated form. This increase by d-Serine application is blocked by 7-chlorokynurenic acid, a specific antagonist at the glycine site of NMDARs, suggesting mediation through NMDARs. Our findings thus demonstrate neuronal SR association with DISC1 and its agglomerates, which can be modulated by d-Serine, thereby validating a novel neuronal SR-DISC1 complex responsive to NMDAR activation and providing a molecular mechanism by which pathways implicated in schizophrenia converge.
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11
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de Almeida V, Martins-de-Souza D. Cannabinoids and glial cells: possible mechanism to understand schizophrenia. Eur Arch Psychiatry Clin Neurosci 2018; 268:727-737. [PMID: 29392440 DOI: 10.1007/s00406-018-0874-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/24/2018] [Indexed: 01/03/2023]
Abstract
Clinical and neurobiological findings have reported the involvement of endocannabinoid signaling in the pathophysiology of schizophrenia. This system modulates dopaminergic and glutamatergic neurotransmission that is associated with positive, negative, and cognitive symptoms of schizophrenia. Despite neurotransmitter impairments, increasing evidence points to a role of glial cells in schizophrenia pathobiology. Glial cells encompass three main groups: oligodendrocytes, microglia, and astrocytes. These cells promote several neurobiological functions, such as myelination of axons, metabolic and structural support, and immune response in the central nervous system. Impairments in glial cells lead to disruptions in communication and in the homeostasis of neurons that play role in pathobiology of disorders such as schizophrenia. Therefore, data suggest that glial cells may be a potential pharmacological tool to treat schizophrenia and other brain disorders. In this regard, glial cells express cannabinoid receptors and synthesize endocannabinoids, and cannabinoid drugs affect some functions of these cells that can be implicated in schizophrenia pathobiology. Thus, the aim of this review is to provide data about the glial changes observed in schizophrenia, and how cannabinoids could modulate these alterations.
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Affiliation(s)
- Valéria de Almeida
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), Rua Monteiro Lobato 255, Campinas, SP, 13083-862, Brazil.
| | - Daniel Martins-de-Souza
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), Rua Monteiro Lobato 255, Campinas, SP, 13083-862, Brazil.,Instituto Nacional de Biomarcadores em Neuropsiquiatria (INBION), Conselho Nacional de Desenvolvimento Científico e Tecnológico, São Paulo, Brazil
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12
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Gao X, Mi Y, Guo N, Xu H, Jiang P, Zhang R, Xu L, Gou X. Glioma in Schizophrenia: Is the Risk Higher or Lower? Front Cell Neurosci 2018; 12:289. [PMID: 30233327 PMCID: PMC6129591 DOI: 10.3389/fncel.2018.00289] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 08/13/2018] [Indexed: 12/17/2022] Open
Abstract
Whether persons with schizophrenia have a higher or lower incidence of cancer has been discussed for a long time. Due to the complex mechanisms and characteristics of different types of cancer, it is difficult to evaluate the exact relationship between cancers and schizophrenia without considering the type of tumor. Schizophrenia, a disabling mental illness that is now recognized as a neurodevelopmental disorder, is more correlated with brain tumors, such as glioma, than other types of tumors. Thus, we mainly focused on the relationship between schizophrenia and glioma morbidity. Glioma tumorigenesis and schizophrenia may share similar mechanisms; gene/pathway disruption would affect neurodevelopment and reduce the risk of glioma. The molecular defects of disrupted-in-schizophrenia-1 (DISC1), P53, brain-derived neurotrophic factor (BDNF) and C-X-C chemokine receptors type 4 (CXCR4) involved in schizophrenia pathogenesis might play opposite roles in glioma development. Many microRNAs (miRNAs) such as miR-183, miR-9, miR-137 and miR-126 expression change may be involved in the cross talk between glioma prevalence and schizophrenia. Finally, antipsychotic drugs may have antitumor effects. All these factors show that persons with schizophrenia have a decreased incidence of glioma; therefore, epidemiological investigation and studies comparing genetic and epigenetic aberrations involved in both of these complex diseases should be performed. These studies can provide more insightful knowledge about glioma and schizophrenia pathophysiology and help to determine the target/strategies for the prevention and treatment of the two diseases.
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Affiliation(s)
- Xingchun Gao
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic Medical Sciences & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, China.,State Key Laboratory of Military Stomatology, Department of Anesthesiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Yajing Mi
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic Medical Sciences & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, China
| | - Na Guo
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic Medical Sciences & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, China
| | - Hao Xu
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic Medical Sciences & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, China.,State Key Laboratory of Military Stomatology, Department of Anesthesiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Pengtao Jiang
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic Medical Sciences & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, China
| | - Ruisan Zhang
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic Medical Sciences & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, China
| | - Lixian Xu
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic Medical Sciences & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, China.,State Key Laboratory of Military Stomatology, Department of Anesthesiology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Xingchun Gou
- Shaanxi Key Laboratory of Brain Disorders & Institute of Basic Medical Sciences & Institute of Basic and Translational Medicine, Xi'an Medical University, Xi'an, China
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13
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Disrupted in schizophrenia 1 (DISC1) inhibits glioblastoma development by regulating mitochondria dynamics. Oncotarget 2018; 7:85963-85974. [PMID: 27852062 PMCID: PMC5349889 DOI: 10.18632/oncotarget.13290] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 11/07/2016] [Indexed: 12/12/2022] Open
Abstract
Glioblastoma(GBM) is one of the most common and aggressive malignant primary tumors of the central nervous system and mitochondria have been proposed to participate in GBM tumorigenesis. Previous studies have identified a potential role of Disrupted in Schizophrenia 1 (DISC1), a multi-compartmentalized protein, in mitochondria. But whether DISC1 could regulate GBM tumorigenesis via mitochondria is still unknown. We determined the expression level of DISC1 by both bioinformatics analysis and tissue analysis, and found that DISC1 was highly expressed in GBM. Knocking down of DISC1 by shRNA in GBM cells significantly inhibited cell proliferation both in vitro and in vivo. In addition, down-regulation of DISC1 decreased cell migration and invasion of GBM and self renewal capacity of glioblastoma stem-like cells. Furthermore, multiple independent rings or spheres could be observed in mitochondria in GBM depleted of DISC1, while normal filamentous morphology was observed in control cells, demonstrating that DISC1 affected the mitochondrial dynamic. Dynamin-related protein 1 (Drp1) was reported to contribute to mitochondrial dynamic regulation and influence glioma cells proliferation and invasion by RHOA/ ROCK1 pathway. Our data showed a significant decrease of Drp1 both in mRNA and protein level in GBM lack of DISC1, indicating that DISC1 maybe affect the mitochondrial dynamic by regulating Drp1. Taken together, our findings reveal that DISC1 affects glioblastoma cell development via mitochondria dynamics partly by down regulation of Drp1.
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14
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Mei YY, Wu DC, Zhou N. Astrocytic Regulation of Glutamate Transmission in Schizophrenia. Front Psychiatry 2018; 9:544. [PMID: 30459650 PMCID: PMC6232167 DOI: 10.3389/fpsyt.2018.00544] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 10/12/2018] [Indexed: 01/19/2023] Open
Abstract
According to the glutamate hypothesis of schizophrenia, the abnormality of glutamate transmission induced by hypofunction of NMDA receptors (NMDARs) is causally associated with the positive and negative symptoms of schizophrenia. However, the underlying mechanisms responsible for the changes in glutamate transmission in schizophrenia are not fully understood. Astrocytes, the major regulatory glia in the brain, modulate not only glutamate metabolism but also glutamate transmission. Here we review the recent progress in understanding the role of astrocytes in schizophrenia. We focus on the astrocytic mechanisms of (i) glutamate synthesis via the glutamate-glutamine cycle, (ii) glutamate clearance by excitatory amino acid transporters (EAATs), (iii) D-serine release to activate NMDARs, and (iv) glutamatergic target engagement biomarkers. Abnormality in these processes is highly correlated with schizophrenia phenotypes. These findings will shed light upon further investigation of pathogenesis as well as improvement of biomarkers and therapies for schizophrenia.
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Affiliation(s)
- Yu-Ying Mei
- Translational Medicine Research Center, China Medical University Hospital, Taichung, Taiwan.,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
| | - Dong Chuan Wu
- Translational Medicine Research Center, China Medical University Hospital, Taichung, Taiwan.,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
| | - Ning Zhou
- Translational Medicine Research Center, China Medical University Hospital, Taichung, Taiwan.,Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
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15
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Um JW. Roles of Glial Cells in Sculpting Inhibitory Synapses and Neural Circuits. Front Mol Neurosci 2017; 10:381. [PMID: 29180953 PMCID: PMC5694142 DOI: 10.3389/fnmol.2017.00381] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/01/2017] [Indexed: 01/04/2023] Open
Abstract
Glial cells are essential for every aspect of normal neuronal development, synapse formation, and function in the central nervous system (CNS). Astrocytes secrete a variety of factors that regulate synaptic connectivity and circuit formation. Microglia also modulate synapse development through phagocytic activity. Most of the known actions of CNS glial cells are limited to roles at excitatory synapses. Nevertheless, studies have indicated that both astrocytes and microglia shape inhibitory synaptic connections through various mechanisms, including release of regulatory molecules, direct contact with synaptic terminals, and utilization of mediators in the extracellular matrix. This review summarizes recent investigations into the mechanisms underlying CNS glial cell-mediated inhibitory synapse development.
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Affiliation(s)
- Ji Won Um
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
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16
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Jiang H, Wu M, Liu Y, Song L, Li S, Wang X, Zhang YF, Fang J, Wu S. Serine racemase deficiency attenuates choroidal neovascularization and reduces nitric oxide and VEGF levels by retinal pigment epithelial cells. J Neurochem 2017; 143:375-388. [PMID: 28892569 DOI: 10.1111/jnc.14214] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 08/16/2017] [Accepted: 09/05/2017] [Indexed: 02/01/2023]
Abstract
Choroidal neovascularization (CNV) is a leading cause of blindness in age-related macular degeneration. Production of vascular endothelial growth factor (VEGF) and macrophage recruitment by retinal pigment epithelial cells (RPE) significantly contributes to the process of CNV in an experimental CNV model. Serine racemase (SR) is expressed in retinal neurons and glial cells, and its product, d-serine, is an endogenous co-agonist of N-methyl-d-aspartate receptor. Activation of the receptor results in production of nitric oxide (. NO), a molecule that promotes retinal and choroidal neovascularization. These observations suggest possible roles of SR in CNV. With laser-injured CNV mice, we found that inactivation of SR-coding gene (Srrnull ) significantly reduced CNV volume, neovascular density, and invading macrophages. We exploited the underlying mechanism in vivo and ex vivo. RPE from wild-type (WT) mice expressed SR. To explore the possible downstream target of SR inactivation, we showed that choroid/RPE homogenates extracted from laser-injured Srrnull mice contained less inducible nitric oxide synthase and decreased phospho-VEGFR2 compared to amounts in WT mice. In vitro, inflammation-primed WT RPEs expressed more inducible NOS, produced more. NO and VEGF than did inflammation-primed Srrnull RPEs. When co-cultured with inflammation-primed Srrnull RPE, significantly fewer RF/6A-a cell line of choroidal endothelial cell, migrated to the opposite side of the insert membrane than did cells co-cultured with pre-treated WT RPE. Altogether, SR deficiency reduces RPE response to laser-induced inflammatory stimuli, resulting in decreased production of a cascade of pro-angiogenic cytokines, including. NO and VEGF, and reduced macrophage recruitment, which contribute synergistically to attenuated angiogenesis.
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Affiliation(s)
- Haiyan Jiang
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou, Zhejiang, China
| | - Mengjuan Wu
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou, Zhejiang, China
| | - Yimei Liu
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou, Zhejiang, China
| | - Liping Song
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou, Zhejiang, China
| | - Shifeng Li
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xianwei Wang
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou, Zhejiang, China
| | - Yun-Feng Zhang
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou, Zhejiang, China
| | - Junxu Fang
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou, Zhejiang, China
| | - Shengzhou Wu
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Wenzhou, Zhejiang, China
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17
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Nelson DL, Applegate GA, Beio ML, Graham DL, Berkowitz DB. Human serine racemase structure/activity relationship studies provide mechanistic insight and point to position 84 as a hot spot for β-elimination function. J Biol Chem 2017; 292:13986-14002. [PMID: 28696262 DOI: 10.1074/jbc.m117.777904] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 06/26/2017] [Indexed: 11/06/2022] Open
Abstract
There is currently great interest in human serine racemase, the enzyme responsible for producing the NMDA co-agonist d-serine. Reported correlation of d-serine levels with disorders including Alzheimer's disease, ALS, and ischemic brain damage (elevated d-serine) and schizophrenia (reduced d-serine) has further piqued this interest. Reported here is a structure/activity relationship study of position Ser84, the putative re-face base. In the most extreme case of functional reprogramming, the S84D mutant displays a dramatic reversal of β-elimination substrate specificity in favor of l-serine over the normally preferred l-serine-O-sulfate (∼1200-fold change in kcat/Km ratios) and l (l-THA; ∼5000-fold change in kcat/Km ratios) alternative substrates. On the other hand, the S84T (which performs l-Ser racemization activity), S84A (good kcat but high Km for l-THA elimination), and S84N mutants (nearly WT efficiency for l-Ser elimination) displayed intermediate activity, all showing a preference for the anionic substrates, but generally attenuated compared with the native enzyme. Inhibition studies with l-erythro-β-hydroxyaspartate follow this trend, with both WT serine racemase and the S84N mutant being competitively inhibited, with Ki = 31 ± 1.5 μm and 1.5 ± 0.1 mm, respectively, and the S84D being inert to inhibition. Computational modeling pointed to a key role for residue Arg-135 in binding and properly positioning the l-THA and l-serine-O-sulfate substrates and the l-erythro-β-hydroxyaspartate inhibitor. Examination of available sequence data suggests that Arg-135 may have originated for l-THA-like β-elimination function in earlier evolutionary variants, and examination of available structural data suggests that a Ser84-H2O-Lys114 hydrogen-bonding network in human serine racemase lowers the pKa of the Ser84re-face base.
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Affiliation(s)
- David L Nelson
- From the Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588
| | - Greg A Applegate
- From the Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588
| | - Matthew L Beio
- From the Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588
| | - Danielle L Graham
- From the Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588
| | - David B Berkowitz
- From the Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588.
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18
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Wu S, Barger SW. Disrupted-in-schizophrenia-1 as a broader link of glutamatergic transmission to schizophrenia impacts cerebral neurochemistry via the production of the 'gliotransmitter' d-serine, a NMDA receptor coagonist. J Neurochem 2017; 138:503-5. [PMID: 27501180 DOI: 10.1111/jnc.13699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 06/07/2016] [Indexed: 01/07/2023]
Abstract
This Editorial highlights a study by Xia and coworkers in the current issue of the Journal of Neurochemistry, in which the authors reveal a possible mechanistic link between DISC1 (disrupted-in-schizophrenia-1), a genetic risk factor for schizophrenia, and N-methyl-d-aspartate receptor (NMDAR) that is also linked with schizophrenia. The authors show that perturbed communication between DISC1 and NMDARs represents a hidden perpetrator for abnormal dendritic and synaptic maturation. Read the highlighted article 'DISC1, astrocytes and neuronal maturation: a possible mechanistic link with implications for mental disorders' on page 518.
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Affiliation(s)
- Shengzhou Wu
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.,State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Steven W Barger
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.,Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA.,Geriatric Research Education and Clinical Center, Central Arkansas Veterans Healthcare System, Little Rock, Arkansas, USA
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19
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Hertz L, Chen Y. Importance of astrocytes for potassium ion (K+) homeostasis in brain and glial effects of K+ and its transporters on learning. Neurosci Biobehav Rev 2016; 71:484-505. [DOI: 10.1016/j.neubiorev.2016.09.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/12/2016] [Accepted: 09/23/2016] [Indexed: 10/20/2022]
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