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Li Y, Guo Y, Bröer A, Dai L, Brӧer S, Yan R. Cryo-EM structure of the human Asc-1 transporter complex. Nat Commun 2024; 15:3036. [PMID: 38589439 PMCID: PMC11001984 DOI: 10.1038/s41467-024-47468-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 04/02/2024] [Indexed: 04/10/2024] Open
Abstract
The Alanine-Serine-Cysteine transporter 1 (Asc-1 or SLC7A10) forms a crucial heterodimeric transporter complex with 4F2hc (SLC3A2) through a covalent disulfide bridge. This complex enables the sodium-independent transport of small neutral amino acids, including L-Alanine (L-Ala), Glycine (Gly), and D-Serine (D-Ser), within the central nervous system (CNS). D-Ser and Gly are two key endogenous glutamate co-agonists that activate N-methyl-d-aspartate (NMDA) receptors by binding to the allosteric site. Mice deficient in Asc-1 display severe symptoms such as tremors, ataxia, and seizures, leading to early postnatal death. Despite its physiological importance, the functional mechanism of the Asc-1-4F2hc complex has remained elusive. Here, we present cryo-electron microscopy (cryo-EM) structures of the human Asc-1-4F2hc complex in its apo state, D-Ser bound state, and L-Ala bound state, resolved at 3.6 Å, 3.5 Å, and 3.4 Å, respectively. Through detailed structural analysis and transport assays, we uncover a comprehensive alternating access mechanism that underlies conformational changes in the complex. In summary, our findings reveal the architecture of the Asc-1 and 4F2hc complex and provide valuable insights into substrate recognition and the functional cycle of this essential transporter complex.
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Affiliation(s)
- Yaning Li
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong Province, China
- Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen, Guangdong Province, China
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yingying Guo
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| | - Angelika Bröer
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Lu Dai
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong Province, China
| | - Stefan Brӧer
- Research School of Biology, Australian National University, Canberra, ACT, Australia.
| | - Renhong Yan
- Department of Biochemistry, Key University Laboratory of Metabolism and Health of Guangdong, School of Medicine, Southern University of Science and Technology, Shenzhen, Guangdong Province, China.
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2
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Marchesani F, Michielon A, Viale E, Bianchera A, Cavazzini D, Pollegioni L, Murtas G, Mozzarelli A, Bettati S, Peracchi A, Campanini B, Bruno S. Phosphoserine Aminotransferase Pathogenetic Variants in Serine Deficiency Disorders: A Functional Characterization. Biomolecules 2023; 13:1219. [PMID: 37627284 PMCID: PMC10452355 DOI: 10.3390/biom13081219] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/27/2023] Open
Abstract
In humans, the phosphorylated pathway (PP) converts the glycolytic intermediate D-3-phosphoglycerate (3-PG) into L-serine through the enzymes 3-phosphoglycerate dehydrogenase, phosphoserine aminotransferase (PSAT) and phosphoserine phosphatase. From the pathogenic point of view, the PP in the brain is particularly relevant, as genetic defects of any of the three enzymes are associated with a group of neurometabolic disorders known as serine deficiency disorders (SDDs). We recombinantly expressed and characterized eight variants of PSAT associated with SDDs and two non-SDD associated variants. We show that the pathogenetic mechanisms in SDDs are extremely diverse, including low affinity of the cofactor pyridoxal 5'-phosphate and thermal instability for S179L and G79W PSAT, loss of activity of the holo form for R342W PSAT, aggregation for D100A PSAT, increased Km for one of the substrates with invariant kcats for S43R PSAT, and a combination of increased Km and decreased kcat for C245R PSAT. Finally, we show that the flux through the in vitro reconstructed PP at physiological concentrations of substrates and enzymes is extremely sensitive to alterations of the functional properties of PSAT variants, confirming PSAT dysfunctions as a cause of SSDs.
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Affiliation(s)
| | | | | | | | - Davide Cavazzini
- Department of Chemistry/Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy
| | - Loredano Pollegioni
- The Protein Factory 2.0, Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
| | - Giulia Murtas
- The Protein Factory 2.0, Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
| | | | - Stefano Bettati
- Department of Medicine and Surgery, University of Parma, 43124 Parma, Italy
- Biopharmanet-TEC, University of Parma, 43124 Parma, Italy
- Institute of Biophysics, CNR, 56124 Pisa, Italy
| | - Alessio Peracchi
- Department of Chemistry/Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy
| | - Barbara Campanini
- Department of Food and Drug, University of Parma, 43124 Parma, Italy
- Biopharmanet-TEC, University of Parma, 43124 Parma, Italy
| | - Stefano Bruno
- Department of Food and Drug, University of Parma, 43124 Parma, Italy
- Biopharmanet-TEC, University of Parma, 43124 Parma, Italy
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3
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Functional Characterization and Structural Modeling of a Novel Glycine Oxidase from Variovorax paradoxus Iso1. Appl Environ Microbiol 2022; 88:e0107722. [PMID: 36377957 PMCID: PMC9746326 DOI: 10.1128/aem.01077-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The N-acyl-d-amino acid amidohydrolase (N-d-AAase) of Variovorax paradoxus Iso1 can enantioselectively catalyze the zinc-assisted deacetylation of N-acyl-d-amino acids to yield consistent d-amino acids. A putative FAD-binding glycine/d-amino acid oxidase was located immediately upstream of the N-d-AAase gene. The gene encoding this protein was cloned into Escherichia coli BL21 (DE3)pLysS and overexpressed at 25°C for 6 h with 0.5 mM isopropyl β-d-1-thiogalactopyranoside induction. After purification, the tag-free recombinant protein was obtained. The enzyme could metabolize glycine, sarcosine, and d-alanine, but not l-amino acids or bulky d-amino acids. Protein modeling further supported these results, demonstrating that glycine, sarcosine, and d-alanine could fit into the pocket of the enzyme's activation site, while l-alanine and d-threonine were out of position. Therefore, this protein was proposed as a glycine oxidase, and we designated it VpGO. Interestingly, VpGO showed low sequence similarity to other well-characterized glycine oxidases. We found that VpGO and N-d-AAase were expressed on the same mRNA and could be transcriptionally induced by various N-acetyl-d-amino acids. Western blotting and zymography showed that both proteins had similar expression patterns in response to different types of inducers. Thus, we have identified a novel glycine oxidase that is co-regulated with N-d-AAase in an operon, and metabolizes N-acyl-d-amino acids in the metabolically versatile V. paradoxus Iso1. IMPORTANCE The Gram-negative bacterium Variovorax paradoxus has numerous metabolic capabilities, including the association with important catabolic processes and the promotion of plant growth. We had previously identified and characterized an N-acyl-d-amino-acid amidohydrolase (N-d-AAase) gene from the strain of V. paradoxus Iso1. The aim of this study was to isolate and characterize (both in vitro and in vivo) another potential gene found in the promoter region of this N-d-AAase gene. The protein was identified as a glycine oxidase, and the gene existed in an operon with N-d-AAase. The structural basis for its FAD-binding potential and substrate stereo-specificity were also elucidated. This study first reported a novel glycine oxidase from V. paradoxus. We believe that our study makes a significant contribution to the literature, because this enzyme has great potential for use as an industrial catalysis, as a biosensor, and in agricultural biotechnology.
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The Role of D-Serine and D-Aspartate in the Pathogenesis and Therapy of Treatment-Resistant Schizophrenia. Nutrients 2022; 14:nu14235142. [PMID: 36501171 PMCID: PMC9736950 DOI: 10.3390/nu14235142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/28/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
Schizophrenia (Sch) is a severe and widespread mental disorder. Antipsychotics (APs) of the first and new generations as the first-line treatment of Sch are not effective in about a third of cases and are also unable to treat negative symptoms and cognitive deficits of schizophrenics. This explains the search for new therapeutic strategies for a disease-modifying therapy for treatment-resistant Sch (TRS). Biological compounds are of great interest to researchers and clinicians, among which D-Serine (D-Ser) and D-Aspartate (D-Asp) are among the promising ones. The Sch glutamate theory suggests that neurotransmission dysfunction caused by glutamate N-methyl-D-aspartate receptors (NMDARs) may represent a primary deficiency in this mental disorder and play an important role in the development of TRS. D-Ser and D-Asp are direct NMDAR agonists and may be involved in modulating the functional activity of dopaminergic neurons. This narrative review demonstrates both the biological role of D-Ser and D-Asp in the normal functioning of the central nervous system (CNS) and in the pathogenesis of Sch and TRS. Particular attention is paid to D-Ser and D-Asp as promising components of a nutritive disease-modifying therapy for TRS.
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5
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Dysfunctional d-aspartate metabolism in BTBR mouse model of idiopathic autism. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140531. [PMID: 32853769 DOI: 10.1016/j.bbapap.2020.140531] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 07/22/2020] [Accepted: 07/31/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Autism spectrum disorders (ASD) comprise a heterogeneous group of neurodevelopmental conditions characterized by impairment in social interaction, deviance in communication, and repetitive behaviors. Dysfunctional ionotropic NMDA and AMPA receptors, and metabotropic glutamate receptor 5 activity at excitatory synapses has been recently linked to multiple forms of ASD. Despite emerging evidence showing that d-aspartate and d-serine are important neuromodulators of glutamatergic transmission, no systematic investigation on the occurrence of these D-amino acids in preclinical ASD models has been carried out. METHODS Through HPLC and qPCR analyses we investigated d-aspartate and d-serine metabolism in the brain and serum of four ASD mouse models. These include BTBR mice, an idiopathic model of ASD, and Cntnap2-/-, Shank3-/-, and 16p11.2+/- mice, three established genetic mouse lines recapitulating high confidence ASD-associated mutations. RESULTS Biochemical and gene expression mapping in Cntnap2-/-, Shank3-/-, and 16p11.2+/- failed to find gross cerebral and serum alterations in d-aspartate and d-serine metabolism. Conversely, we found a striking and stereoselective increased d-aspartate content in the prefrontal cortex, hippocampus and serum of inbred BTBR mice. Consistent with biochemical assessments, in the same brain areas we also found a robust reduction in mRNA levels of d-aspartate oxidase, encoding the enzyme responsible for d-aspartate catabolism. CONCLUSIONS Our results demonstrated the presence of disrupted d-aspartate metabolism in a widely used animal model of idiopathic ASD. GENERAL SIGNIFICANCE Overall, this work calls for a deeper investigation of D-amino acids in the etiopathology of ASD and related developmental disorders.
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6
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Asc-1 Transporter (SLC7A10): Homology Models And Molecular Dynamics Insights Into The First Steps Of The Transport Mechanism. Sci Rep 2020; 10:3731. [PMID: 32111919 PMCID: PMC7048771 DOI: 10.1038/s41598-020-60617-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 02/14/2020] [Indexed: 12/02/2022] Open
Abstract
The alanine-serine-cysteine transporter Asc-1 regulates the synaptic availability of d-serine and glycine (the two co-agonists of the NMDA receptor) and is regarded as an important drug target. To shuttle the substrate from the extracellular space to the cytoplasm, this transporter undergoes multiple distinct conformational states. In this work, homology modeling, substrate docking and molecular dynamics simulations were carried out to learn more about the transition between the “outward-open” and “outward-open occluded” states. We identified a transition state involving the highly-conserved unwound TM6 region in which the Phe243 flips close to the d-serine substrate without major movements of TM6. This feature and those of other key residues are proposed to control the binding site and substrate translocation. Competitive inhibitors ACPP, LuAE00527 and SMLC were docked and their binding modes at the substrate binding site corroborated the key role played by Phe243 of TM6. For ACPP and LuAE00527, strong hydrophobic interactions with this residue hinder its mobility and prevent the uptake and the efflux of substrates. As for SMLC, the weaker interactions maintain the flexibility of Phe243 and the efflux process. Overall, we propose a molecular basis for the inhibition of substrate translocation of the Asc-1 transporter that should be valuable for rational drug design.
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7
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Cuprizone-treated mice, a possible model of schizophrenia, highlighting the simultaneous abnormalities of GABA, serine and glycine in hippocampus. Schizophr Res 2019; 210:326-328. [PMID: 31296416 DOI: 10.1016/j.schres.2019.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 05/28/2019] [Accepted: 06/16/2019] [Indexed: 12/29/2022]
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8
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Quintero M, Stanisic D, Cruz G, Pontes JGM, Costa TBBC, Tasic L. Metabolomic Biomarkers in Mental Disorders: Bipolar Disorder and Schizophrenia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1118:271-293. [PMID: 30747428 DOI: 10.1007/978-3-030-05542-4_14] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Psychiatric disorders are some of the most impairing human diseases. Among them, bipolar disorder and schizophrenia are the most common. Both have complicated diagnostics due to their phenotypic, biological, and genetic heterogeneity, unknown etiology, and the underlying biological pathways, and molecular mechanisms are still not completely understood. Given the multifactorial complexity of these disorders, identification and implementation of metabolic biomarkers would assist in their early detection and diagnosis and facilitate disease monitoring and treatment responses. To date, numerous studies have utilized metabolomics to better understand psychiatric disorders, and findings from these studies have begun to converge. In this chapter, we briefly describe some of the metabolomic biomarkers found in these two disorders.
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Affiliation(s)
- Melissa Quintero
- Laboratory of Chemical Biology, Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Danijela Stanisic
- Laboratory of Chemical Biology, Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Guilherme Cruz
- Laboratory of Chemical Biology, Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - João G M Pontes
- Laboratory of Microbial Chemical Biology, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Tássia Brena Barroso Carneiro Costa
- Laboratory of Chemical Biology, Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Ljubica Tasic
- Laboratory of Chemical Biology, Department of Organic Chemistry, Institute of Chemistry, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil.
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9
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MacKay MAB, Kravtsenyuk M, Thomas R, Mitchell ND, Dursun SM, Baker GB. D-Serine: Potential Therapeutic Agent and/or Biomarker in Schizophrenia and Depression? Front Psychiatry 2019; 10:25. [PMID: 30787885 PMCID: PMC6372501 DOI: 10.3389/fpsyt.2019.00025] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 01/15/2019] [Indexed: 11/17/2022] Open
Abstract
D-Serine is a potent co-agonist at the NMDA glutamate receptor and has been the object of many preclinical studies to ascertain the nature of its metabolism, its regional and cellular distribution in the brain, its physiological functions and its possible clinical relevance. The enzymes involved in its formation and catabolism are serine racemase (SR) and D-amino acid oxidase (DAAO), respectively, and manipulations of the activity of those enzymes have been useful in developing animal models of schizophrenia and in providing clues to the development of potential new antipsychotic strategies. Clinical studies have been conducted in schizophrenia patients to evaluate body fluid levels of D-serine and/or to use D-serine alone or in combination with antipsychotics to determine its effectiveness as a therapeutic agent. D-serine has also been used in combination with DAAO inhibitors in preclinical investigations, and interesting results have been obtained. Genetic studies and postmortem brain studies have also been conducted on D-serine and the enzymes involved in its metabolism. It is also of considerable interest that in recent years clinical and preclinical investigations have suggested that D-serine may also have antidepressant properties. Clinical studies have also shown that D-serine may be a biomarker for antidepressant response to ketamine. Relevant to both schizophrenia and depression, preclinical and clinical studies with D-serine indicate that it may be effective in reducing cognitive dysfunction.
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Affiliation(s)
- Mary-Anne B MacKay
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Maryana Kravtsenyuk
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Rejish Thomas
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Nicholas D Mitchell
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Serdar M Dursun
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Glen B Baker
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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10
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Winship IR, Dursun SM, Baker GB, Balista PA, Kandratavicius L, Maia-de-Oliveira JP, Hallak J, Howland JG. An Overview of Animal Models Related to Schizophrenia. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2019; 64:5-17. [PMID: 29742910 PMCID: PMC6364139 DOI: 10.1177/0706743718773728] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Schizophrenia is a heterogeneous psychiatric disorder that is poorly treated with current therapies. In this brief review, we provide an update regarding the use of animal models to study schizophrenia in an attempt to understand its aetiology and develop novel therapeutic strategies. Tremendous progress has been made developing and validating rodent models that replicate the aetiologies, brain pathologies, and behavioural abnormalities associated with schizophrenia in humans. Here, models are grouped into 3 categories-developmental, drug induced, and genetic-to reflect the heterogeneous risk factors associated with schizophrenia. Each of these models is associated with varied but overlapping pathophysiology, endophenotypes, behavioural abnormalities, and cognitive impairments. Studying schizophrenia using multiple models will permit an understanding of the core features of the disease, thereby facilitating preclinical research aimed at the development and validation of better pharmacotherapies to alter the progression of schizophrenia or alleviate its debilitating symptoms.
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Affiliation(s)
- Ian R Winship
- 1 Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta
| | - Serdar M Dursun
- 2 Department of Psychiatry, Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta.,3 National Institute of Science and Technology-Translational Science, Brazil
| | - Glen B Baker
- 2 Department of Psychiatry, Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta.,3 National Institute of Science and Technology-Translational Science, Brazil
| | - Priscila A Balista
- 4 Department of Pharmacy, Centro Universitario das Faculdades Metropolitanas Unidas, São Paulo, Brazil
| | - Ludmyla Kandratavicius
- 5 Department of Neuroscience and Behavior, Faculty of Medicine of Ribeirao Preto, University of São Paulo, Ribeirao Preto, Brazil
| | - Joao Paulo Maia-de-Oliveira
- 3 National Institute of Science and Technology-Translational Science, Brazil.,6 Department of Clinical Medicine, Rio Grande do Norte Federal University, Natal, Brazil
| | - Jaime Hallak
- 3 National Institute of Science and Technology-Translational Science, Brazil.,5 Department of Neuroscience and Behavior, Faculty of Medicine of Ribeirao Preto, University of São Paulo, Ribeirao Preto, Brazil.,7 Department of Psychiatry (NRU), University of Alberta, Edmonton, Alberta
| | - John G Howland
- 8 Department of Physiology, University of Saskatchewan, Saskatoon, Saskatchewan
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11
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Qian PP, Wang S, Feng KR, Ren YJ. Molecular modeling studies of 1,2,4-triazine derivatives as novel h-DAAO inhibitors by 3D-QSAR, docking and dynamics simulations. RSC Adv 2018; 8:14311-14327. [PMID: 35540777 PMCID: PMC9079910 DOI: 10.1039/c8ra00094h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 03/30/2018] [Indexed: 02/01/2023] Open
Abstract
Computational modeling methods were successfully applied to discover new 1,2,4-triazine compounds as potential h-DAAO inhibitors.
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Affiliation(s)
- Ping Ping Qian
- School of Chemical and Environmental Engineering
- Shanghai Institute of Technology
- China
| | - Shuai Wang
- School of Chemical and Environmental Engineering
- Shanghai Institute of Technology
- China
| | - Kai Rui Feng
- School of Chemical and Environmental Engineering
- Shanghai Institute of Technology
- China
| | - Yu Jie Ren
- School of Chemical and Environmental Engineering
- Shanghai Institute of Technology
- China
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12
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MacKay MAB, Paylor JW, Wong JTF, Winship IR, Baker GB, Dursun SM. Multidimensional Connectomics and Treatment-Resistant Schizophrenia: Linking Phenotypic Circuits to Targeted Therapeutics. Front Psychiatry 2018; 9:537. [PMID: 30425662 PMCID: PMC6218602 DOI: 10.3389/fpsyt.2018.00537] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 10/10/2018] [Indexed: 01/08/2023] Open
Abstract
Schizophrenia is a very complex syndrome that involves widespread brain multi-dysconnectivity. Neural circuits within specific brain regions and their links to corresponding regions are abnormal in the illness. Theoretical models of dysconnectivity and the investigation of connectomics and brain network organization have been examined in schizophrenia since the early nineteenth century. In more recent years, advancements have been achieved with the development of neuroimaging tools that have provided further clues to the structural and functional organization of the brain and global neural networks in the illness. Neural circuitry that extends across prefrontal, temporal and parietal areas of the cortex as well as limbic and other subcortical brain regions is disrupted in schizophrenia. As a result, many patients have a poor response to antipsychotic treatment and treatment failure is common. Treatment resistance that is specific to positive, negative, and cognitive domains of the illness may be related to distinct circuit phenotypes unique to treatment-refractory disease. Currently, there are no customized neural circuit-specific and targeted therapies that address this neural dysconnectivity. Investigation of targeted therapeutics that addresses particular areas of substantial regional dysconnectivity is an intriguing approach to precision medicine in schizophrenia. This review examines current findings of system and circuit-level brain dysconnectivity in treatment-resistant schizophrenia based on neuroimaging studies. Within a connectome context, on-off circuit connectivity synonymous with excitatory and inhibitory neuronal pathways is discussed. Mechanistic cellular, neurochemical and molecular studies are included with specific emphasis given to cell pathology and synaptic communication in glutamatergic and GABAergic systems. In this review we attempt to deconstruct how augmenting treatments may be applied within a circuit context to improve circuit integration and treatment response. Clinical studies that have used a variety of glutamate receptor and GABA interneuron modulators, nitric oxide-based therapies and a variety of other strategies as augmenting treatments with antipsychotic drugs are included. This review supports the idea that the methodical mapping of system-level networks to both on (excitatory) and off (inhibitory) cellular circuits specific to treatment-resistant disease may be a logical and productive approach in directing future research toward the advancement of targeted pharmacotherapeutics in schizophrenia.
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Affiliation(s)
- Mary-Anne B MacKay
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - John W Paylor
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - James T F Wong
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Ian R Winship
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Glen B Baker
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Serdar M Dursun
- Neurochemical Research Unit and Bebensee Schizophrenia Research Unit, Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
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13
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Kohiki T, Kato Y, Nishikawa Y, Yorita K, Sagawa I, Denda M, Inokuma T, Shigenaga A, Fukui K, Otaka A. Elucidation of inhibitor-binding pockets ofd-amino acid oxidase using docking simulation and N-sulfanylethylanilide-based labeling technology. Org Biomol Chem 2017; 15:5289-5297. [DOI: 10.1039/c7ob00633k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Binding pockets of a schizophrenia-relatedd-amino acid oxidase to its inhibitor were clarified by docking simulation and protein labeling experiments.
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Affiliation(s)
- Taiki Kohiki
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences
- Tokushima University
- Tokushima 770-8505
- Japan
| | - Yusuke Kato
- Division of Enzyme Pathophysiology
- The Institute for Enzyme Research (KOSOKEN)
- Tokushima University
- Tokushima 770-8503
- Japan
| | - Yusuke Nishikawa
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences
- Tokushima University
- Tokushima 770-8505
- Japan
| | - Kazuko Yorita
- Division of Enzyme Pathophysiology
- The Institute for Enzyme Research (KOSOKEN)
- Tokushima University
- Tokushima 770-8503
- Japan
| | - Ikuko Sagawa
- Support Center for Advanced Medical Sciences
- Institute of Biomedical Sciences
- Tokushima University Graduate School
- Tokushima 770-8505
- Japan
| | - Masaya Denda
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences
- Tokushima University
- Tokushima 770-8505
- Japan
| | - Tsubasa Inokuma
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences
- Tokushima University
- Tokushima 770-8505
- Japan
| | - Akira Shigenaga
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences
- Tokushima University
- Tokushima 770-8505
- Japan
- PRESTO
| | - Kiyoshi Fukui
- Division of Enzyme Pathophysiology
- The Institute for Enzyme Research (KOSOKEN)
- Tokushima University
- Tokushima 770-8503
- Japan
| | - Akira Otaka
- Institute of Biomedical Sciences and Graduate School of Pharmaceutical Sciences
- Tokushima University
- Tokushima 770-8505
- Japan
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14
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Dhami K, MacKay M, Maia-de-Oliveira JP, Hallak J, Todd K, Baker G, Dursun S. Novel Targets for Development of Drugs for Treating Schizophrenia: Focus on Glycine, D-Serine and Nitric Oxide. ACTA ACUST UNITED AC 2016. [DOI: 10.5455/bcp.20130629042437] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Kamaldeep Dhami
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Marnie MacKay
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Joao Paulo Maia-de-Oliveira
- National Institute of Science and Technology in Translational Medicine, Ribeirao Preto Medical School, Sao Paulo, Brazil
| | - Jaime Hallak
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
- National Institute of Science and Technology in Translational Medicine, Ribeirao Preto Medical School, Sao Paulo, Brazil
| | - Kathryn Todd
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Glen Baker
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
- National Institute of Science and Technology in Translational Medicine, Ribeirao Preto Medical School, Sao Paulo, Brazil
| | - Serdar Dursun
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
- National Institute of Science and Technology in Translational Medicine, Ribeirao Preto Medical School, Sao Paulo, Brazil
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15
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Thomas R, Baker G, Dursun S, Todd K, Dhami K, Chue J, Chue P. Glycine Reuptake Inhibitors in the Treatment of Negative Symptoms of Schizophrenia. ACTA ACUST UNITED AC 2016. [DOI: 10.5455/bcp.20140918102748] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Reji Thomas
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Glen Baker
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Serdar Dursun
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Kathryn Todd
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Kamaldeep Dhami
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - James Chue
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
| | - Pierre Chue
- Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta, Canada
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16
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Zheng HF, Wang WQ, Li XM, Rauw G, Baker GB. Body fluid levels of neuroactive amino acids in autism spectrum disorders: a review of the literature. Amino Acids 2016; 49:57-65. [PMID: 27686223 PMCID: PMC5241332 DOI: 10.1007/s00726-016-2332-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 09/08/2016] [Indexed: 01/08/2023]
Abstract
A review of studies on the body fluid levels of neuroactive amino acids, including glutamate, glutamine, taurine, gamma-aminobutyric acid (GABA), glycine, tryptophan, d-serine, and others, in autism spectrum disorders (ASD) is given. The results reported in the literature are generally inconclusive and contradictory, but there has been considerable variation among the previous studies in terms of factors such as age, gender, number of subjects, intelligence quotient, and psychoactive medication being taken. Future studies should include simultaneous analyses of a large number of amino acids [including d-serine and branched-chain amino acids (BCAAs)] and standardization of the factors mentioned above. It may also be appropriate to use saliva sampling to detect amino acids in ASD patients in the future—this is noninvasive testing that can be done easily more frequently than other sampling, thus providing more dynamic monitoring.
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Affiliation(s)
- Hui-Fei Zheng
- Mental Health Research Laboratory, Xiamen Xianyue Hospital, Xiamen, Fujian, China.,Neurochemical Research Unit, Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Wen-Qiang Wang
- Mental Health Research Laboratory, Xiamen Xianyue Hospital, Xiamen, Fujian, China.
| | - Xin-Min Li
- Neurochemical Research Unit, Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Gail Rauw
- Neurochemical Research Unit, Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Glen B Baker
- Neurochemical Research Unit, Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.
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17
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Sakimura K, Nakao K, Yoshikawa M, Suzuki M, Kimura H. A novel Na(+) -Independent alanine-serine-cysteine transporter 1 inhibitor inhibits both influx and efflux of D-Serine. J Neurosci Res 2016; 94:888-95. [PMID: 27302861 DOI: 10.1002/jnr.23772] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 04/15/2016] [Accepted: 05/06/2016] [Indexed: 01/28/2023]
Abstract
NMDA receptor dysfunctions are hypothesized to underlie the pathophysiology of schizophrenia, and treatment with D-serine (D-Ser), an NMDA receptor coagonist, may improve the clinical symptoms of schizophrenia. Thus, upregulating the synaptic D-Ser level is a novel strategy for schizophrenia treatment. Na(+) -independent alanine-serine-cysteine transporter 1 (asc-1) is a transporter responsible for regulating the extracellular D-Ser levels in the brain. In this study, we discovered a novel asc-1 inhibitor, (+)-amino(1-(3,5-dichlorophenyl)-3,5-dimethyl-1H-pyrazol-4-yl)acetic acid (ACPP), and assessed its pharmacological profile. ACPP inhibited the D-[(3) H]Ser uptake in human asc-1-expressing CHO cells and rat primary neurons with IC50 values of 0.72 ± 0.13 and 0.89 ± 0.30 μM, respectively. In accordance with the lower asc-1 expression levels in astrocytes, ACPP did not inhibit D-Ser uptake in rat primary astrocytes. In a microdialysis study, ACPP dose dependently decreased the extracellular D-Ser levels in the rat hippocampus under the same conditions in which the asc-1 inhibitor S-methyl-L-cysteine (SMLC) increased it. To obtain insights into this difference, we conducted a D-[(3) H]Ser efflux assay using asc-1-expressing CHO cells. ACPP inhibited D-[(3) H]Ser efflux, whereas SMLC increased it. These results suggest that ACPP is a novel inhibitor of asc-1. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Katsuya Sakimura
- CNS Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Kanagawa, Japan
| | - Kenji Nakao
- Biomolecular Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Kanagawa, Japan
| | - Masato Yoshikawa
- Inflammation Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Kanagawa, Japan
| | - Motohisa Suzuki
- CNS Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Kanagawa, Japan
| | - Haruhide Kimura
- CNS Drug Discovery Unit, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Kanagawa, Japan
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18
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Zink M, Correll CU. Glutamatergic agents for schizophrenia: current evidence and perspectives. Expert Rev Clin Pharmacol 2015; 8:335-52. [PMID: 25916667 DOI: 10.1586/17512433.2015.1040393] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Suboptimal outcomes in schizophrenia are a consequence of lacking insight into the etiology, biomarkers and treatment-relevant subgroups, the therapeutic restriction to dopaminergic-modulating antipsychotics that fail to significantly improve negative and cognitive symptoms, non-adherence, and, in the case of treatment-resistance, the underutilization of clozapine. Evidence suggests additional, extra-dopaminergic abnormalities in amino acid neurotransmission, particularly the glutamatergic system. Antidopaminergic antipsychotics modulate this system on several levels, as do mood stabilizers, including lamotrigine, topiramate and pregabaline. Recently, agonists at metabotropic glutamate receptors and glycine uptake inhibitors failed in large placebo-controlled trials for schizophrenia. Problems to overcome for successfully leveraging glutamatergic agents for schizophrenia are patient selection, focus on positive symptoms and late disease stages, and dose-response relationships. Because glutamate guides processes of brain development and maturation, clinical research should focus on the at-risk mental state or first-episode psychosis, address cognition and negative symptoms and use monotherapy designs in parallel to augmentation strategies.
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Affiliation(s)
- Mathias Zink
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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19
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Takahashi S, Shimada K, Nozawa S, Goto M, Abe K, Kera Y. Possible role of a histidine residue in the substrate specificity of yeast d-aspartate oxidase. J Biochem 2015; 159:371-8. [DOI: 10.1093/jb/mvv108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 09/29/2015] [Indexed: 02/02/2023] Open
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20
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Hin N, Duvall B, Ferraris D, Alt J, Thomas AG, Rais R, Rojas C, Wu Y, Wozniak K, Slusher BS, Tsukamoto T. 6-Hydroxy-1,2,4-triazine-3,5(2H,4H)-dione Derivatives as Novel D-Amino Acid Oxidase Inhibitors. J Med Chem 2015; 58:7258-72. [PMID: 26309148 PMCID: PMC5003509 DOI: 10.1021/acs.jmedchem.5b00482] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Indexed: 02/04/2023]
Abstract
A series of 2-substituted 6-hydroxy-1,2,4-triazine-3,5(2H,4H)-dione derivatives were synthesized as inhibitors of D-amino acid oxidase (DAAO). Many compounds in this series were found to be potent DAAO inhibitors, with IC50 values in the double-digit nanomolar range. The 6-hydroxy-1,2,4-triazine-3,5(2H,4H)-dione pharmacophore appears metabolically resistant to O-glucuronidation unlike other structurally related DAAO inhibitors. Among them, 6-hydroxy-2-(naphthalen-1-ylmethyl)-1,2,4-triazine-3,5(2H,4H)-dione 11h was found to be selective over a number of targets and orally available in mice. Furthermore, oral coadministration of D-serine with 11h enhanced the plasma levels of D-serine in mice compared to the oral administration of D-serine alone, demonstrating its ability to serve as a pharmacoenhancer of D-serine.
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Affiliation(s)
- Niyada Hin
- Brain Science Institute, Department of Neurology, and Department of
Molecular and Comparative
Pathobiology, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Bridget Duvall
- Brain Science Institute, Department of Neurology, and Department of
Molecular and Comparative
Pathobiology, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Dana Ferraris
- Brain Science Institute, Department of Neurology, and Department of
Molecular and Comparative
Pathobiology, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Jesse Alt
- Brain Science Institute, Department of Neurology, and Department of
Molecular and Comparative
Pathobiology, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Ajit G. Thomas
- Brain Science Institute, Department of Neurology, and Department of
Molecular and Comparative
Pathobiology, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Rana Rais
- Brain Science Institute, Department of Neurology, and Department of
Molecular and Comparative
Pathobiology, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Camilo Rojas
- Brain Science Institute, Department of Neurology, and Department of
Molecular and Comparative
Pathobiology, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Ying Wu
- Brain Science Institute, Department of Neurology, and Department of
Molecular and Comparative
Pathobiology, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Krystyna
M. Wozniak
- Brain Science Institute, Department of Neurology, and Department of
Molecular and Comparative
Pathobiology, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Barbara S. Slusher
- Brain Science Institute, Department of Neurology, and Department of
Molecular and Comparative
Pathobiology, Johns Hopkins University, Baltimore, Maryland 21205, United States
| | - Takashi Tsukamoto
- Brain Science Institute, Department of Neurology, and Department of
Molecular and Comparative
Pathobiology, Johns Hopkins University, Baltimore, Maryland 21205, United States
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21
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Abstract
Go/No Go decisions concerning development of any single compound determine investment in increasingly costly studies from Phases I-III. Such decisions are problematic for CNS drug development where the variety of molecular targets in the brain have stimulated decades of studies without major therapeutic advances. Many costly studies do not even yield interpretable results as to whether the mechanism being pursued has therapeutic potential. Therefore, both industry and the public sector have implemented a decision making strategy based on whether a compound can test a molecular hypothesis of drug action. One requires, at a minimum, compelling evidence in humans that a compound both interacts with its presumed molecular targets in brain and ideally documents a CNS functional consequence of the interaction prior to efficacy studies. This strategy will much more quickly rule out ineffective mechanisms although it does not address the problem of poorly predictive models of novel CNS drug efficacy.
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22
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Antipsychotic treatment modulates glutamate transport and NMDA receptor expression. Eur Arch Psychiatry Clin Neurosci 2014; 264 Suppl 1:S67-82. [PMID: 25214389 DOI: 10.1007/s00406-014-0534-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 09/02/2014] [Indexed: 12/21/2022]
Abstract
Schizophrenia patients often suffer from treatment-resistant cognitive and negative symptoms, both of which are influenced by glutamate neurotransmission. Innovative therapeutic strategies such as agonists at metabotropic glutamate receptors or glycin reuptake inhibitors try to modulate the brain's glutamate network. Interactions of amino acids with monoamines have been described on several levels, and first- and second-generation antipsychotic agents (FGAs, SGAs) are known to exert modulatory effects on the glutamatergic system. This review summarizes the current knowledge on effects of FGAs and SGAs on glutamate transport and receptor expression derived from pharmacological studies. Such studies serve as a control for molecular findings in schizophrenia brain tissue and are clinically relevant. Moreover, they may validate animal models for psychosis, foster basic research on antipsychotic substances and finally lead to a better understanding of how monoaminergic and amino acid neurotransmissions are intertwined. In the light of these results, important differences dependent on antipsychotic substances, dosage and duration of treatment became obvious. While some post-mortem findings might be confounded with multifold drug effects, others are unlikely to be influenced by antipsychotic treatment and could represent important markers of schizophrenia pathophysiology. In similarity to the convergence of toxic and psychotomimetic effects of dopaminergic, serotonergic and anti-glutamatergic substances, the therapeutic mechanisms of SGAs might merge on a yet to be defined molecular level. In particular, serotonergic effects of SGAs, such as an agonism at 5HT1A receptors, represent important targets for further clinical research.
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23
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Current and emergent treatments for symptoms and neurocognitive impairment in schizophrenia. ACTA ACUST UNITED AC 2014; 1:107-120. [PMID: 26301175 DOI: 10.1007/s40501-014-0010-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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24
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Glycine reuptake inhibition: a promising therapeutic strategy in the treatment of schizophrenia? Future Med Chem 2014; 5:1475-7. [PMID: 24024940 DOI: 10.4155/fmc.13.118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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25
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Dietary cyclic dipeptides, apoptosis and psychiatric disorders: a hypothesis. Med Hypotheses 2014; 82:740-3. [PMID: 24717821 DOI: 10.1016/j.mehy.2014.03.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 02/27/2014] [Accepted: 03/08/2014] [Indexed: 12/14/2022]
Abstract
Cyclic dipeptides from food and intestinal yeast cyclic dipeptides may play a role in causing psychiatric disorders such as schizophrenia. From cancer research, cyclic dipeptides such as cyclo (proline-phenylalanine) have been found to activate the pathways of apoptosis and to cause programmed cell death. Activation of such pathways is also thought to be important in causing the neurodevelopmental abnormalities seen in disorders such as schizophrenia and autistic disorder, and also may be important in Alzheimer's. Cyclic dipeptides are found in foods such as malt and cocoa and beer. The intestinal yeast Candida albicans also synthesizes cyclic dipeptides. These dipeptides may be activating apoptosis pathways throughout fetal development and postnatal development, leading to some of the changes seen in brain in schizophrenia and in other psychiatric disorders. These compounds should be researched further to see if they play a role in causing these brain changes. In addition, these cyclic dipeptides are considered within the larger context of research on amino acids and other cyclic dipeptides in neurotransmission and neurophysiology. A better understanding of the role of these cyclic dipeptides in psychiatric disorders could lead to strategies for prevention and treatment of these disorders.
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Chue P, Lalonde JK. Addressing the unmet needs of patients with persistent negative symptoms of schizophrenia: emerging pharmacological treatment options. Neuropsychiatr Dis Treat 2014; 10:777-89. [PMID: 24855363 PMCID: PMC4020880 DOI: 10.2147/ndt.s43404] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The negative symptoms of schizophrenia represent an impairment of normal emotional responses, thought processes and behaviors, and include blunting or flattening of affect, alogia/aprosody, avolition/apathy, anhedonia, and asociality. Negative symptoms contribute to a reduced quality of life, increased functional disability, increased burden of illness, and poorer long-term outcomes, to a greater degree than positive symptoms. Primary negative symptoms are prominent and persistent in up to 26% of patients with schizophrenia, and they are estimated to occur in up to 58% of outpatients at any given time. Negative symptoms respond less well to medications than positive symptoms, and to date treatment options for negative symptoms have been limited, with no accepted standard treatment. Modest benefits have been reported with a variety of different agents, including second-generation antipsychotics and add-on therapy with antidepressants and other pharmacological classes. Recent clinical research focusing on negative symptoms target novel biological systems, such as glutamatergic neurotransmission. Different approaches include: enhancing N-methyl-D-aspartate receptor function with agents that bind directly to the glycine ligand site or with glycine reuptake inhibitors; influencing the metabotropic glutamate receptor (mGluR2/3) with positive allosteric modulators; and stimulating nicotinic acetylcholine receptors. In conclusion, the lack of clearly efficacious pharmacological treatments for the management of negative symptoms represents a significant unmet need, especially considering the importance of these symptoms on patient outcomes. Hence, further research to identify and characterize novel pharmacological treatments for negative symptoms is greatly needed.
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Affiliation(s)
- Pierre Chue
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
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