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Holeček M. Aspartic Acid in Health and Disease. Nutrients 2023; 15:4023. [PMID: 37764806 PMCID: PMC10536334 DOI: 10.3390/nu15184023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 09/12/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
Aspartic acid exists in L- and D-isoforms (L-Asp and D-Asp). Most L-Asp is synthesized by mitochondrial aspartate aminotransferase from oxaloacetate and glutamate acquired by glutamine deamidation, particularly in the liver and tumor cells, and transamination of branched-chain amino acids (BCAAs), particularly in muscles. The main source of D-Asp is the racemization of L-Asp. L-Asp transported via aspartate-glutamate carrier to the cytosol is used in protein and nucleotide synthesis, gluconeogenesis, urea, and purine-nucleotide cycles, and neurotransmission and via the malate-aspartate shuttle maintains NADH delivery to mitochondria and redox balance. L-Asp released from neurons connects with the glutamate-glutamine cycle and ensures glycolysis and ammonia detoxification in astrocytes. D-Asp has a role in brain development and hypothalamus regulation. The hereditary disorders in L-Asp metabolism include citrullinemia, asparagine synthetase deficiency, Canavan disease, and dicarboxylic aminoaciduria. L-Asp plays a role in the pathogenesis of psychiatric and neurologic disorders and alterations in BCAA levels in diabetes and hyperammonemia. Further research is needed to examine the targeting of L-Asp metabolism as a strategy to fight cancer, the use of L-Asp as a dietary supplement, and the risks of increased L-Asp consumption. The role of D-Asp in the brain warrants studies on its therapeutic potential in psychiatric and neurologic disorders.
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Affiliation(s)
- Milan Holeček
- Department of Physiology, Faculty of Medicine in Hradec Králové, Charles University, Šimkova 870, 500 03 Hradec Králové, Czech Republic
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2
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Polyakov IV, Khrenova MG, Grigorenko BL, Nemukhin AV. Mechanism of chemical reactions in the active site of aspartate N-acetyltransferase NAT8L revealed by molecular modeling. MENDELEEV COMMUNICATIONS 2022. [DOI: 10.1016/j.mencom.2022.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Drosophila melanogaster Uncoupling Protein-4A (UCP4A) Catalyzes a Unidirectional Transport of Aspartate. Int J Mol Sci 2022; 23:ijms23031020. [PMID: 35162943 PMCID: PMC8834685 DOI: 10.3390/ijms23031020] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/14/2022] [Accepted: 01/16/2022] [Indexed: 12/23/2022] Open
Abstract
Uncoupling proteins (UCPs) form a distinct subfamily of the mitochondrial carrier family (MCF) SLC25. Four UCPs, DmUCP4A-C and DmUCP5, have been identified in Drosophila melanogaster on the basis of their sequence homology with mammalian UCP4 and UCP5. In a Parkinson’s disease model, DmUCP4A showed a protective role against mitochondrial dysfunction, by increasing mitochondrial membrane potential and ATP synthesis. To date, DmUCP4A is still an orphan of a biochemical function, although its possible involvement in mitochondrial uncoupling has been ruled out. Here, we show that DmUCP4A expressed in bacteria and reconstituted in phospholipid vesicles catalyzes a unidirectional transport of aspartate, which is saturable and inhibited by mercurials and other mitochondrial carrier inhibitors to various degrees. Swelling experiments carried out in yeast mitochondria have demonstrated that the unidirectional transport of aspartate catalyzed by DmUCP4 is not proton-coupled. The biochemical function of DmUCP4A has been further confirmed in a yeast cell model, in which growth has required an efflux of aspartate from mitochondria. Notably, DmUCP4A is the first UCP4 homolog from any species to be biochemically characterized. In Drosophila melanogaster, DmUCP4A could be involved in the transport of aspartate from mitochondria to the cytosol, in which it could be used for protein and nucleotide synthesis, as well as in the biosynthesis of ß-alanine and N-acetylaspartate, which play key roles in signal transmission in the central nervous system.
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4
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Fogh S, Dipace G, Bie A, Veiga‐da‐Cunha M, Hansen J, Kjeldsen M, Mosegaard S, Ribes A, Gregersen N, Aagaard L, Van Schaftingen E, Olsen RKJ. Variants in the ethylmalonyl-CoA decarboxylase (ECHDC1) gene: a novel player in ethylmalonic aciduria? J Inherit Metab Dis 2021; 44:1215-1225. [PMID: 33973257 PMCID: PMC8518634 DOI: 10.1002/jimd.12394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 05/03/2021] [Accepted: 05/07/2021] [Indexed: 12/13/2022]
Abstract
Ethylmalonic acid (EMA) is a major and potentially cytotoxic metabolite associated with short-chain acyl-CoA dehydrogenase (SCAD) deficiency, a condition whose status as a disease is uncertain. Unexplained high EMA is observed in some individuals with complex neurological symptoms, who carry the SCAD gene (ACADS) variants, c.625G>A and c.511C>T. The variants have a high allele frequency in the general population, but are significantly overrepresented in individuals with elevated EMA. This has led to the idea that these variants need to be associated with variants in other genes to cause hyperexcretion of ethylmalonic acid and possibly a diseased state. Ethylmalonyl-CoA decarboxylase (ECHDC1) has been described and characterized as an EMA metabolite repair enzyme, however, its clinical relevance has never been investigated. In this study, we sequenced the ECHDC1 gene (ECHDC1) in 82 individuals, who were reported with unexplained high EMA levels due to the presence of the common ACADS variants only. Three individuals with ACADS c.625G>A variants were found to be heterozygous for ECHDC1 loss-of-function variants. Knockdown experiments of ECHDC1, in healthy human cells with different ACADS c.625G>A genotypes, showed that ECHDC1 haploinsufficiency and homozygosity for the ACADS c.625G>A variant had a synergistic effect on cellular EMA excretion. This study reports the first cases of ECHDC1 gene defects in humans and suggests that ECHDC1 may be involved in elevated EMA excretion in only a small group of individuals with the common ACADS variants. However, a direct link between ECHDC1/ACADS deficiency, EMA and disease could not be proven.
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Affiliation(s)
- Sarah Fogh
- Research Unit for Molecular Medicine, Department for Clinical MedicineAarhus University and Aarhus University HospitalAarhusDenmark
- Department of BiomedicineAarhus UniversityAarhusDenmark
| | - Graziana Dipace
- Research Unit for Molecular Medicine, Department for Clinical MedicineAarhus University and Aarhus University HospitalAarhusDenmark
| | - Anne Bie
- Research Unit for Molecular Medicine, Department for Clinical MedicineAarhus University and Aarhus University HospitalAarhusDenmark
| | | | - Jakob Hansen
- Department of Forensic MedicineAarhus University HospitalAarhusDenmark
| | - Margrethe Kjeldsen
- Research Unit for Molecular Medicine, Department for Clinical MedicineAarhus University and Aarhus University HospitalAarhusDenmark
| | - Signe Mosegaard
- Research Unit for Molecular Medicine, Department for Clinical MedicineAarhus University and Aarhus University HospitalAarhusDenmark
| | - Antonia Ribes
- Secció d'Errors Congènits del Metabolisme‐IBC, Servei de Bioquímica i Genètica MolecularHospital Clínic, IDIBAPS, CIBERERBarcelonaSpain
| | - Niels Gregersen
- Research Unit for Molecular Medicine, Department for Clinical MedicineAarhus University and Aarhus University HospitalAarhusDenmark
| | - Lars Aagaard
- Department of BiomedicineAarhus UniversityAarhusDenmark
| | | | - Rikke K. J. Olsen
- Research Unit for Molecular Medicine, Department for Clinical MedicineAarhus University and Aarhus University HospitalAarhusDenmark
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5
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Hussain MS, Wang Q, Viola RE. Engineering of a critical membrane-anchored enzyme for high solubility and catalytic activity. Arch Biochem Biophys 2021; 703:108870. [PMID: 33831357 DOI: 10.1016/j.abb.2021.108870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/18/2021] [Accepted: 03/30/2021] [Indexed: 10/21/2022]
Abstract
Membrane-associated proteins carry out a wide range of essential cellular functions but the structural characterization needed to understand these functions is dramatically underrepresented in the Protein Data Bank. Producing a soluble, stable and active form of a membrane-associated protein presents formidable challenges, as evidenced by the variety of approaches that have been attempted with a multitude of different membrane proteins to achieve this goal. Aspartate N-acetyltransferase (ANAT) is a membrane-anchored enzyme that performs a critical function, the synthesis of N-acetyl-l-aspartate (NAA), the second most abundant amino acid in the brain. This amino acid is a precursor for a neurotransmitter, and alterations in brain NAA levels have been implicated as a causative effect in Canavan disease and has been suggested to be involved in other neurological disorders. Numerous prior attempts have failed to produce a soluble form of ANAT that is amenable for functional and structural investigations. Through the application of a range of different approaches, including fusion partner constructs, linker modifications, membrane-anchor modifications, and domain truncations, a highly soluble, stable and fully active form of ANAT has now been obtained. Producing this modified enzyme form will accelerate studies aimed at structural characterization and structure-guided inhibitor development.
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Affiliation(s)
- Muhammad S Hussain
- Department of Chemistry & Biochemistry, University of Toledo, Toledo, OH, 43606, USA
| | - Qinzhe Wang
- Department of Chemistry & Biochemistry, University of Toledo, Toledo, OH, 43606, USA
| | - Ronald E Viola
- Department of Chemistry & Biochemistry, University of Toledo, Toledo, OH, 43606, USA.
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6
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Zyśk M, Pikul P, Kowalski R, Lewandowski K, Sakowicz-Burkiewicz M, Pawełczyk T. Neither Excessive Nitric Oxide Accumulation nor Acute Hyperglycemia Affects the N-Acetylaspartate Network in Wistar Rat Brain Cells. Int J Mol Sci 2020; 21:ijms21228541. [PMID: 33198375 PMCID: PMC7697070 DOI: 10.3390/ijms21228541] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 11/09/2020] [Accepted: 11/11/2020] [Indexed: 12/12/2022] Open
Abstract
The N-acetylaspartate network begins in neurons with N-acetylaspartate production catalyzed by aspartate N-acetyltransferase from acetyl-CoA and aspartate. Clinical studies reported a significant depletion in N-acetylaspartate brain level in type 1 diabetic patients. The main goal of this study was to establish the impact of either hyperglycemia or oxidative stress on the N-acetylaspartate network. For the in vitro part of the study, embryonic rat primary neurons were treated by using a nitric oxide generator for 24 h followed by 6 days of post-treatment culture, while the neural stem cells were cultured in media with 25–75 mM glucose. For the in vivo part, male adult Wistar rats were injected with streptozotocin (65 mg/kg body weight, ip) to induce hyperglycemia (diabetes model) and euthanized 2 or 8 weeks later. Finally, the biochemical profile, NAT8L protein/Nat8l mRNA levels and enzymatic activity were analyzed. Ongoing oxidative stress processes significantly affected energy metabolism and cholinergic neurotransmission. However, the applied factors did not affect the N-acetylaspartate network. This study shows that reduced N-acetylaspartate level in type 1 diabetes is not related to oxidative stress and that does not trigger N-acetylaspartate network fragility. To reveal why N-acetylaspartate is reduced in this pathology, other processes should be considered.
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Affiliation(s)
- Marlena Zyśk
- Department of Molecular Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland; (M.S.-B.); (T.P.)
- Correspondence: ; Tel.: +48-58-349-2770
| | - Piotr Pikul
- Laboratory of Molecular and Cellular Nephrology, Polish Academy of Science, 80-308 Gdansk, Poland; (P.P.); (R.K.)
| | - Robert Kowalski
- Laboratory of Molecular and Cellular Nephrology, Polish Academy of Science, 80-308 Gdansk, Poland; (P.P.); (R.K.)
| | | | - Monika Sakowicz-Burkiewicz
- Department of Molecular Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland; (M.S.-B.); (T.P.)
| | - Tadeusz Pawełczyk
- Department of Molecular Medicine, Medical University of Gdansk, 80-211 Gdansk, Poland; (M.S.-B.); (T.P.)
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Low Molecular Weight Dextran Sulfate (ILB ®) Administration Restores Brain Energy Metabolism Following Severe Traumatic Brain Injury in the Rat. Antioxidants (Basel) 2020; 9:antiox9090850. [PMID: 32927770 PMCID: PMC7555574 DOI: 10.3390/antiox9090850] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/06/2020] [Accepted: 09/08/2020] [Indexed: 02/07/2023] Open
Abstract
Traumatic brain injury (TBI) is the leading cause of death and disability in people less than 40 years of age in Western countries. Currently, there are no satisfying pharmacological treatments for TBI patients. In this study, we subjected rats to severe TBI (sTBI), testing the effects of a single subcutaneous administration, 30 min post-impact, of a new low molecular weight dextran sulfate, named ILB®, at three different dose levels (1, 5, and 15 mg/kg body weight). A group of control sham-operated animals and one of untreated sTBI rats were used for comparison (each group n = 12). On day 2 or 7 post-sTBI animals were sacrificed and the simultaneous HPLC analysis of energy metabolites, N-acetylaspartate (NAA), oxidized and reduced nicotinic coenzymes, water-soluble antioxidants, and biomarkers of oxidative/nitrosative stress was carried out on deproteinized cerebral homogenates. Compared to untreated sTBI rats, ILB® improved energy metabolism by increasing ATP, ATP/ adenosine diphosphate ratio (ATP/ADP ratio), and triphosphate nucleosides, dose-dependently increased NAA concentrations, protected nicotinic coenzyme levels and their oxidized over reduced ratios, prevented depletion of ascorbate and reduced glutathione (GSH), and decreased oxidative (malondialdehyde formation) and nitrosative stress (nitrite + nitrate production). Although needing further experiments, these data provide the first evidence that a single post-injury injection of a new low molecular weight dextran sulfate (ILB®) has beneficial effects on sTBI metabolic damages. Due to the absence of adverse effects in humans, ILB® represents a promising therapeutic agent for the treatment of sTBI patients.
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Polyakov IV, Kniga AE, Grigorenko BL, Nemukhin AV. Structure of the Brain N-Acetylaspartate Biosynthetic Enzyme NAT8L Revealed by Computer Modeling. ACS Chem Neurosci 2020; 11:2296-2302. [PMID: 32639720 DOI: 10.1021/acschemneuro.0c00250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We report the results of computational modeling of a three-dimensional all-atom structure of the membrane-associated protein encoded by the NAT8L gene, aspartate N-acetyltransferase, which is essential for brain synthesis of N-acetyl-l-aspartate (NAA). The lack of experimentally derived three-dimensional structures of NAT8L poses one of the obstacles in studies of the mechanism of NAA formation and understanding the precise role of NAA in neurological disorders. We apply a computational protocol employing the contact map prediction, ab initio folding, homology modeling, and refinement to obtain a structure of NAT8L with the aspartate and acetyl coenzyme A cofactors in the protein molecule. To verify the computational protocol, we check its predictive power by reproducing the crystal structure of a related N-acetyltransferase domain, specifically, that from the bacterial N-acetylglutamate synthase. We show that the constructed NAT8L model correlates with structural features of the protein revealed in rare experimental studies. The obtained structure of the enzyme active site with the trapped reactants suggests a mechanism of the acetyl transfer upon NAA formation.
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Affiliation(s)
- Igor V. Polyakov
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russian Federation
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russian Federation
| | - Artem E. Kniga
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russian Federation
| | - Bella L. Grigorenko
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russian Federation
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russian Federation
| | - Alexander V. Nemukhin
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991, Russian Federation
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russian Federation
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9
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Profilo E, Peña-Altamira LE, Corricelli M, Castegna A, Danese A, Agrimi G, Petralla S, Giannuzzi G, Porcelli V, Sbano L, Viscomi C, Massenzio F, Palmieri EM, Giorgi C, Fiermonte G, Virgili M, Palmieri L, Zeviani M, Pinton P, Monti B, Palmieri F, Lasorsa FM. Down-regulation of the mitochondrial aspartate-glutamate carrier isoform 1 AGC1 inhibits proliferation and N-acetylaspartate synthesis in Neuro2A cells. Biochim Biophys Acta Mol Basis Dis 2017; 1863:1422-1435. [DOI: 10.1016/j.bbadis.2017.02.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 02/02/2017] [Accepted: 02/20/2017] [Indexed: 12/26/2022]
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10
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Weindl D, Cordes T, Battello N, Sapcariu SC, Dong X, Wegner A, Hiller K. Bridging the gap between non-targeted stable isotope labeling and metabolic flux analysis. Cancer Metab 2016; 4:10. [PMID: 27110360 PMCID: PMC4842284 DOI: 10.1186/s40170-016-0150-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 03/31/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Metabolism gained increasing interest for the understanding of diseases and to pinpoint therapeutic intervention points. However, classical metabolomics techniques only provide a very static view on metabolism. Metabolic flux analysis methods, on the other hand, are highly targeted and require detailed knowledge on metabolism beforehand. RESULTS We present a novel workflow to analyze non-targeted metabolome-wide stable isotope labeling data to detect metabolic flux changes in a non-targeted manner. Furthermore, we show how similarity-analysis of isotopic enrichment patterns can be used for pathway contextualization of unidentified compounds. We illustrate our approach with the analysis of changes in cellular metabolism of human adenocarcinoma cells in response to decreased oxygen availability. Starting without a priori knowledge, we detect metabolic flux changes, leading to an increased glutamine contribution to acetyl-CoA production, reveal biosynthesis of N-acetylaspartate by N-acetyltransferase 8-like (NAT8L) in lung cancer cells and show that NAT8L silencing inhibits proliferation of A549, JHH-4, PH5CH8, and BEAS-2B cells. CONCLUSIONS Differential stable isotope labeling analysis provides qualitative metabolic flux information in a non-targeted manner. Furthermore, similarity analysis of enrichment patterns provides information on metabolically closely related compounds. N-acetylaspartate and NAT8L are important players in cancer cell metabolism, a context in which they have not received much attention yet.
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Affiliation(s)
- Daniel Weindl
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
| | - Thekla Cordes
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
- />Department of Bioengineering, University of California, Gilman Drive, San Diego, La Jolla, 92037 USA
| | - Nadia Battello
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
| | - Sean C. Sapcariu
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
| | - Xiangyi Dong
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
| | - Andre Wegner
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
| | - Karsten Hiller
- />Luxembourg Centre for Systems Biomedicine, University of Luxembourg, 7, Avenue des Hauts Fourneaux, Esch-sur-Alzette, 4362 Luxembourg
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11
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Wang Q, Zhao M, Parungao GG, Viola RE. Purification and characterization of aspartate N-acetyltransferase: A critical enzyme in brain metabolism. Protein Expr Purif 2016; 119:11-8. [DOI: 10.1016/j.pep.2015.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/02/2015] [Accepted: 11/03/2015] [Indexed: 10/22/2022]
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12
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Menga A, Iacobazzi V, Infantino V, Avantaggiati ML, Palmieri F. The mitochondrial aspartate/glutamate carrier isoform 1 gene expression is regulated by CREB in neuronal cells. Int J Biochem Cell Biol 2015; 60:157-66. [PMID: 25597433 PMCID: PMC4344217 DOI: 10.1016/j.biocel.2015.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 12/04/2014] [Accepted: 01/06/2015] [Indexed: 12/22/2022]
Abstract
The aspartate/glutamate carrier isoform 1 is an essential mitochondrial transporter that exchanges intramitochondrial aspartate and cytosolic glutamate across the inner mitochondrial membrane. It is expressed in brain, heart and muscle and is involved in important biological processes, including myelination. However, the signals that regulate the expression of this transporter are still largely unknown. In this study we first identify a CREB binding site within the aspartate/glutamate carrier gene promoter that acts as a strong enhancer element in neuronal SH-SY5Y cells. This element is regulated by active, phosphorylated CREB protein and by signal pathways that modify the activity of CREB itself and, most noticeably, by intracellular Ca(2+) levels. Specifically, aspartate/glutamate carrier gene expression is induced via CREB by forskolin while it is inhibited by the PKA inhibitor, H89. Furthermore, the CREB-induced activation of gene expression is increased by thapsigargin, which enhances cytosolic Ca(2+), while it is inhibited by BAPTA-AM that reduces cytosolic Ca(2+) or by STO-609, which inhibits CaMK-IV phosphorylation. We further show that CREB-dependent regulation of aspartate/glutamate carrier gene expression occurs in neuronal cells in response to pathological (inflammation) and physiological (differentiation) conditions. Since this carrier is necessary for neuronal functions and is involved in myelinogenesis, our results highlight that targeting of CREB activity and Ca(2+) might be therapeutically exploited to increase aspartate/glutamate carrier gene expression in neurodegenerative diseases.
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Affiliation(s)
- Alessio Menga
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Vito Iacobazzi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy
| | - Vittoria Infantino
- Department of Science, University of Basilicata, Via N. Sauro 85, 85100 Potenza, Italy
| | - Maria Laura Avantaggiati
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA
| | - Ferdinando Palmieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Via Orabona 4, 70125 Bari, Italy.
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13
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Occurrence and subcellular distribution of the NADPHX repair system in mammals. Biochem J 2014; 460:49-58. [PMID: 24611804 DOI: 10.1042/bj20131482] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Hydration of NAD(P)H to NAD(P)HX, which inhibits several dehydrogenases, is corrected by an ATP-dependent dehydratase and an epimerase recently identified as the products of the vertebrate Carkd (carbohydrate kinase domain) and Aibp (apolipoprotein AI-binding protein) genes respectively. The purpose of the present study was to assess the presence of these enzymes in mammalian tissues and determine their subcellular localization. The Carkd gene encodes proteins with a predicted mitochondrial propeptide (mCARKD), a signal peptide (spCARKD) or neither of them (cCARKD). Confocal microscopy analysis of transfected CHO (Chinese-hamster ovary) cells indicated that cCARKD remains in the cytosol, whereas mCARKD and spCARKD are targeted to the mitochondria and the endoplasmic reticulum respectively. Unlike the other two forms, spCARKD is N-glycosylated, supporting its targeting to the endoplasmic reticulum. The Aibp gene encodes two different proteins, which we show to be targeted to the mitochondria (mAIBP) and the cytosol (cAIBP). Quantification of the NAD(P)HX dehydratase and epimerase activities in rat tissues, performed after partial purification, indicated that both enzymes are widely distributed, with total activities of ≈3-10 nmol/min per g of tissue. Liver fractionation by differential centrifugation confirmed the presence of the dehydratase and the epimerase in the cytosol and in mitochondria. These data support the notion that NAD(P)HX repair is extremely widespread.
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14
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Di Pietro V, Amorini AM, Tavazzi B, Vagnozzi R, Logan A, Lazzarino G, Signoretti S, Lazzarino G, Belli A. The molecular mechanisms affecting N-acetylaspartate homeostasis following experimental graded traumatic brain injury. Mol Med 2014; 20:147-57. [PMID: 24515258 DOI: 10.2119/molmed.2013.00153] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 02/03/2014] [Indexed: 11/06/2022] Open
Abstract
To characterize the molecular mechanisms of N-acetylaspartate (NAA) metabolism following traumatic brain injury (TBI), we measured the NAA, adenosine triphosphate (ATP) and adenosine diphosphate (ADP) concentrations and calculated the ATP/ADP ratio at different times from impact, concomitantly evaluating the gene and protein expressions controlling NAA homeostasis (the NAA synthesizing and degrading enzymes N-acetyltransferase 8-like and aspartoacylase, respectively) in rats receiving either mild or severe TBI. The reversible changes in NAA induced by mild TBI were due to a combination of transient mitochondrial malfunctioning with energy crisis (decrease in ATP and in the ATP/ADP ratio) and modulation in the gene and protein levels of N-acetyltransferase 8-like and increase of aspartoacylase levels. The irreversible decrease in NAA following severe TBI, was instead characterized by profound mitochondrial malfunctioning (constant 65% decrease of the ATP/ADP indicating permanent impairment of the mitochondrial phosphorylating capacity), dramatic repression of the N-acetyltransferase 8-like gene and concomitant remarkable increase in the aspartoacylase gene and protein levels. The mechanisms underlying changes in NAA homeostasis following graded TBI might be of note for possible new therapeutic approaches and will help in understanding the effects of repeat concussions occurring during particular periods of the complex NAA recovery process, coincident with the so called window of brain vulnerability.
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Affiliation(s)
- Valentina Di Pietro
- Neuropharmacology and Neurobiology Section, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Angela Maria Amorini
- Institute of Biochemistry and Clinical Biochemistry, Catholic University of Rome, Rome, Italy
| | - Barbara Tavazzi
- Institute of Biochemistry and Clinical Biochemistry, Catholic University of Rome, Rome, Italy
| | - Roberto Vagnozzi
- Department of Biomedicine and Prevention, Section of Neurosurgery, University of Rome Tor Vergata, Rome, Italy
| | - Ann Logan
- Neuropharmacology and Neurobiology Section, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Giacomo Lazzarino
- Institute of Biochemistry and Clinical Biochemistry, Catholic University of Rome, Rome, Italy
| | - Stefano Signoretti
- Division of Neurosurgery, Department of Neurosciences Head and Neck Surgery, San Camillo Hospital, Rome, Italy
| | - Giuseppe Lazzarino
- Department of Biology, Geology and Environmental Sciences, Division of Biochemistry and Molecular Biology, University of Catania, Catania, Italy
| | - Antonio Belli
- Neuropharmacology and Neurobiology Section, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
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15
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Deletion of SHATI/NAT8L increases dopamine D1 receptor on the cell surface in the nucleus accumbens, accelerating methamphetamine dependence. Int J Neuropsychopharmacol 2014; 17:443-53. [PMID: 24246274 DOI: 10.1017/s1461145713001302] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
In a previous report, we identified a novel molecule, SHATI/NAT8L, having an inhibitory effect on methamphetamine (METH)-induced hyperlocomotion, sensitization, and conditioned place preference (CPP). SHATI/NAT8L attenuates the METH-induced increase in dopamine overflow in the nucleus accumbens (NAc) by promoting plasmalemmal and vesicular dopamine uptake. However, the biological functions of the protein remain unclear. In this study, we explored NAT8L-binding proteins using pull-down assays and identified a number of components of the adaptor protein (AP)-2 complex, which is a multimeric protein localized to the plasma membrane that functions to internalize cargo during clathrin-mediated endocytosis. To investigate whether NAT8L regulates the receptor localization to the cell surface, cell-surface dopamine D1 receptor in the NAc of Nat8l knockout (KO) mice was quantified. We found that dopamine D1 receptor on the cell surface was increased in the NAc of Nat8l KO mice compared with the wild type (WT) animals. Consistent with this finding, Nat8l KO mice showed higher basal locomotor activity and heightened sensitivity to D1 agonist compared with WT mice. In addition, METH-induced sensitization and CPP were enhanced in Nat8l KO mice. These results suggest that NAT8L might regulate the localization of cell-surface dopamine D1 receptor, thereby controlling basal behaviour and sensitivity to METH. Furthermore, we observed a single nucleotide polymorphism (SNP) in the human NAT8L gene related to reward dependence, a personality trait, and grey matter volume in the caudate nucleus in healthy subjects, suggesting that NAT8L might also affect human personality.
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16
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Cominelli A, Halbout M, N'Kuli F, Lemoine P, Courtoy PJ, Marbaix E, Tyteca D, Henriet P. A unique C-terminal domain allows retention of matrix metalloproteinase-27 in the endoplasmic reticulum. Traffic 2014; 15:401-17. [PMID: 24548619 DOI: 10.1111/tra.12149] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 01/08/2014] [Accepted: 01/08/2014] [Indexed: 11/29/2022]
Abstract
Matrix metalloproteinase-27 (MMP-27) is poorly characterized. Sequence comparison suggests that a C-terminal extension (CTE) includes a potential transmembrane domain as in some membrane-type (MT)-MMPs. Having noticed that MMP-27 was barely secreted, we investigated its subcellular localization and addressed CTE contribution for MMP-27 retention. Intracellular MMP-27 was sensitive to endoglycosidase H. Subcellular fractionation and confocal microscopy evidenced retention of endogenous MMP-27 or recombinant rMMP-27 in the endoplasmic reticulum (ER) with locked exit across the intermediate compartment (ERGIC). Conversely, truncated rMMP-27 without CTE accessed downstream secretory compartments (ERGIC and Golgi) and was constitutively secreted. CTE addition to rMMP-10 (a secreted MMP) caused ER retention and blocked secretion. Addition of a PKA target sequence to the cytosolic C-terminus of transmembrane MT1-MMP/MMP-14 led to effective phosphorylation upon forskolin stimulation, but not for MMP-27, excluding transmembrane anchorage. Moreover, MMP-27 was protected from digestion by proteinase K. Finally, MT1-MMP/MMP-14 but neither endogenous nor recombinant MMP-27 partitioned in the detergent phase after Triton X-114 extraction, indicating that MMP-27 is not an integral membrane protein. In conclusion, MMP-27 is efficiently retained within the ER due to its unique CTE, which does not lead to stable membrane insertion. This could represent a novel ER retention system.
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Affiliation(s)
- Antoine Cominelli
- Cell Biology Unit, de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, Box B1.75.05, B-1200, Brussels, Belgium
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17
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Moffett JR, Arun P, Ariyannur PS, Namboodiri AMA. N-Acetylaspartate reductions in brain injury: impact on post-injury neuroenergetics, lipid synthesis, and protein acetylation. FRONTIERS IN NEUROENERGETICS 2013; 5:11. [PMID: 24421768 PMCID: PMC3872778 DOI: 10.3389/fnene.2013.00011] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 12/09/2013] [Indexed: 12/22/2022]
Abstract
N-Acetylaspartate (NAA) is employed as a non-invasive marker for neuronal health using proton magnetic resonance spectroscopy (MRS). This utility is afforded by the fact that NAA is one of the most concentrated brain metabolites and that it produces the largest peak in MRS scans of the healthy human brain. NAA levels in the brain are reduced proportionately to the degree of tissue damage after traumatic brain injury (TBI) and the reductions parallel the reductions in ATP levels. Because NAA is the most concentrated acetylated metabolite in the brain, we have hypothesized that NAA acts in part as an extensive reservoir of acetate for acetyl coenzyme A synthesis. Therefore, the loss of NAA after TBI impairs acetyl coenzyme A dependent functions including energy derivation, lipid synthesis, and protein acetylation reactions in distinct ways in different cell populations. The enzymes involved in synthesizing and metabolizing NAA are predominantly expressed in neurons and oligodendrocytes, respectively, and therefore some proportion of NAA must be transferred between cell types before the acetate can be liberated, converted to acetyl coenzyme A and utilized. Studies have indicated that glucose metabolism in neurons is reduced, but that acetate metabolism in astrocytes is increased following TBI, possibly reflecting an increased role for non-glucose energy sources in response to injury. NAA can provide additional acetate for intercellular metabolite trafficking to maintain acetyl CoA levels after injury. Here we explore changes in NAA, acetate, and acetyl coenzyme A metabolism in response to brain injury.
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Affiliation(s)
- John R. Moffett
- Neuroscience Program, Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health SciencesBethesda, MD, USA
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18
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Pessentheiner AR, Pelzmann HJ, Walenta E, Schweiger M, Groschner LN, Graier WF, Kolb D, Uno K, Miyazaki T, Nitta A, Rieder D, Prokesch A, Bogner-Strauss JG. NAT8L (N-acetyltransferase 8-like) accelerates lipid turnover and increases energy expenditure in brown adipocytes. J Biol Chem 2013; 288:36040-51. [PMID: 24155240 PMCID: PMC3861652 DOI: 10.1074/jbc.m113.491324] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
NAT8L (N-acetyltransferase 8-like) catalyzes the formation of N-acetylaspartate (NAA) from acetyl-CoA and aspartate. In the brain, NAA delivers the acetate moiety for synthesis of acetyl-CoA that is further used for fatty acid generation. However, its function in other tissues remained elusive. Here, we show for the first time that Nat8l is highly expressed in adipose tissues and murine and human adipogenic cell lines and is localized in the mitochondria of brown adipocytes. Stable overexpression of Nat8l in immortalized brown adipogenic cells strongly increases glucose incorporation into neutral lipids, accompanied by increased lipolysis, indicating an accelerated lipid turnover. Additionally, mitochondrial mass and number as well as oxygen consumption are elevated upon Nat8l overexpression. Concordantly, expression levels of brown marker genes, such as Prdm16, Cidea, Pgc1α, Pparα, and particularly UCP1, are markedly elevated in these cells. Treatment with a PPARα antagonist indicates that the increase in UCP1 expression and oxygen consumption is PPARα-dependent. Nat8l knockdown in brown adipocytes has no impact on cellular triglyceride content, lipogenesis, or oxygen consumption, but lipolysis and brown marker gene expression are increased; the latter is also observed in BAT of Nat8l-KO mice. Interestingly, the expression of ATP-citrate lyase is increased in Nat8l-silenced adipocytes and BAT of Nat8l-KO mice, indicating a compensatory mechanism to sustain the acetyl-CoA pool once Nat8l levels are reduced. Taken together, our data show that Nat8l impacts on the brown adipogenic phenotype and suggests the existence of the NAT8L-driven NAA metabolism as a novel pathway to provide cytosolic acetyl-CoA for lipid synthesis in adipocytes.
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Affiliation(s)
- Ariane R. Pessentheiner
- From the Institute for Genomics and Bioinformatics, Graz University of Technology, Petergasse 14, 8010 Graz, Austria, ,the Institute of Biochemistry, Graz University of Technology, Petergasse 12, 8010 Graz, Austria
| | - Helmut J. Pelzmann
- From the Institute for Genomics and Bioinformatics, Graz University of Technology, Petergasse 14, 8010 Graz, Austria, ,the Institute of Biochemistry, Graz University of Technology, Petergasse 12, 8010 Graz, Austria
| | - Evelyn Walenta
- From the Institute for Genomics and Bioinformatics, Graz University of Technology, Petergasse 14, 8010 Graz, Austria
| | - Martina Schweiger
- the Institute for Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
| | | | | | - Dagmar Kolb
- Institute of Cell Biology, Histology, and Embryology, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria, ,the Core Facility Ultrastructure Analysis, Center for Medical Research, Medical University of Graz, Stiftingtalstrasse 24, 8010 Graz, Austria
| | - Kyosuke Uno
- the Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan, and
| | - Toh Miyazaki
- the Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan, and
| | - Atsumi Nitta
- the Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan, and
| | - Dietmar Rieder
- the Division of Bioinformatics, Biocenter, Innsbruck Medical University, Innrain 80, 6020 Innsbruck, Austria
| | - Andreas Prokesch
- From the Institute for Genomics and Bioinformatics, Graz University of Technology, Petergasse 14, 8010 Graz, Austria, ,the Institute of Biochemistry, Graz University of Technology, Petergasse 12, 8010 Graz, Austria
| | - Juliane G. Bogner-Strauss
- From the Institute for Genomics and Bioinformatics, Graz University of Technology, Petergasse 14, 8010 Graz, Austria, ,the Institute of Biochemistry, Graz University of Technology, Petergasse 12, 8010 Graz, Austria, , To whom correspondence should be addressed: Petersgasse 14/5, 8010 Graz, Austria. Tel.: 43-316-873-5337; E-mail:
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19
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Toriumi K, Ikami M, Kondo M, Mouri A, Koseki T, Ibi D, Furukawa-Hibi Y, Nagai T, Mamiya T, Nitta A, Yamada K, Nabeshima T. SHATI/NAT8L regulates neurite outgrowth via microtubule stabilization. J Neurosci Res 2013; 91:1525-32. [DOI: 10.1002/jnr.23273] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 04/09/2013] [Accepted: 06/06/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Kazuya Toriumi
- Department of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences, Meijo University; Nagoya Japan
- The Academic Frontier Project for Private University, Comparative Cognitive Science Institutes, Meijo University; Nagoya Japan
| | - Miki Ikami
- Department of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences, Meijo University; Nagoya Japan
| | - Mizuki Kondo
- Department of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences, Meijo University; Nagoya Japan
| | - Akihiro Mouri
- Department of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences, Meijo University; Nagoya Japan
| | - Takenao Koseki
- Department of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences, Meijo University; Nagoya Japan
- The Academic Frontier Project for Private University, Comparative Cognitive Science Institutes, Meijo University; Nagoya Japan
| | - Daisuke Ibi
- Department of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences, Meijo University; Nagoya Japan
- Department of Neuropsychopharmacology and Hospital Pharmacy; Nagoya University Graduate School of Medicine; Nagoya Japan
- Department of Regional Pharmaceutical Care and Sciences; Graduate School of Pharmaceutical Sciences, Meijo University; Nagoya Japan
| | - Yoko Furukawa-Hibi
- Department of Neuropsychopharmacology and Hospital Pharmacy; Nagoya University Graduate School of Medicine; Nagoya Japan
| | - Taku Nagai
- Department of Neuropsychopharmacology and Hospital Pharmacy; Nagoya University Graduate School of Medicine; Nagoya Japan
| | - Takayoshi Mamiya
- Department of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences, Meijo University; Nagoya Japan
- The Academic Frontier Project for Private University, Comparative Cognitive Science Institutes, Meijo University; Nagoya Japan
| | - Atsumi Nitta
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Science; Graduate School of Medicine and Pharmaceutical Science, University of Toyama; Toyama Japan
| | - Kiyofumi Yamada
- Department of Neuropsychopharmacology and Hospital Pharmacy; Nagoya University Graduate School of Medicine; Nagoya Japan
| | - Toshitaka Nabeshima
- Department of Chemical Pharmacology; Graduate School of Pharmaceutical Sciences, Meijo University; Nagoya Japan
- The Academic Frontier Project for Private University, Comparative Cognitive Science Institutes, Meijo University; Nagoya Japan
- Department of Regional Pharmaceutical Care and Sciences; Graduate School of Pharmaceutical Sciences, Meijo University; Nagoya Japan
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20
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Satori CP, Henderson MM, Krautkramer EA, Kostal V, Distefano MM, Arriaga EA. Bioanalysis of eukaryotic organelles. Chem Rev 2013; 113:2733-811. [PMID: 23570618 PMCID: PMC3676536 DOI: 10.1021/cr300354g] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Chad P. Satori
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Michelle M. Henderson
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Elyse A. Krautkramer
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Vratislav Kostal
- Tescan, Libusina trida 21, Brno, 623 00, Czech Republic
- Institute of Analytical Chemistry ASCR, Veveri 97, Brno, 602 00, Czech Republic
| | - Mark M. Distefano
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Edgar A. Arriaga
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
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21
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Du F, Cooper A, Cohen BM, Renshaw PF, Öngür D. Water and metabolite transverse T2 relaxation time abnormalities in the white matter in schizophrenia. Schizophr Res 2012; 137:241-5. [PMID: 22356802 PMCID: PMC3351533 DOI: 10.1016/j.schres.2012.01.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 01/17/2012] [Accepted: 01/19/2012] [Indexed: 11/26/2022]
Abstract
Multiple lines of evidence suggest that microstructural abnormalities in the white matter are important in the pathophysiology of schizophrenia. Diffusion MRI approaches which can provide evidence on tissue structure have been widely used to probe these abnormalities in vivo, but transverse relaxation times (T2) may provide additional insights since they are determined by molecule-microenvironment interactions not revealed by diffusion MRI. T2 of water - located both intra and extracellularly - and N-acetylaspartate (NAA - located intracellularly) reflect related but distinct processes due to their differential localization and interactions with other molecules. In this study, we collected water and NAA T2 data from 16 healthy subjects (HC), and 16 patients with schizophrenia (SZ) at 4 T in a 9 cm(3) voxel in the right prefrontal white matter. The SZ group had longer water but shorter NAA T2 relaxation times when compared with the HC group. This pattern resulted in a statistically significant metabolite×group interaction (F(18,1):4.980, p=0.039). Prolongation of water T2 and shortening of NAA T2 is consistent with an impoverishment of white matter macromolecule structures (including myelin) and abnormal intra-axonal milieu and volume in SZ.
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Affiliation(s)
- Fei Du
- McLean Hospital, Belmont, MA
,Harvard Medical School, Boston, MA
| | | | - Bruce M. Cohen
- McLean Hospital, Belmont, MA
,Harvard Medical School, Boston, MA
| | | | - Dost Öngür
- McLean Hospital, Belmont, MA
,Harvard Medical School, Boston, MA
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