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Grønbæk-Thygesen M, Hartmann-Petersen R. Cellular and molecular mechanisms of aspartoacylase and its role in Canavan disease. Cell Biosci 2024; 14:45. [PMID: 38582917 PMCID: PMC10998430 DOI: 10.1186/s13578-024-01224-6] [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: 12/15/2023] [Accepted: 03/24/2024] [Indexed: 04/08/2024] Open
Abstract
Canavan disease is an autosomal recessive and lethal neurological disorder, characterized by the spongy degeneration of the white matter in the brain. The disease is caused by a deficiency of the cytosolic aspartoacylase (ASPA) enzyme, which catalyzes the hydrolysis of N-acetyl-aspartate (NAA), an abundant brain metabolite, into aspartate and acetate. On the physiological level, the mechanism of pathogenicity remains somewhat obscure, with multiple, not mutually exclusive, suggested hypotheses. At the molecular level, recent studies have shown that most disease linked ASPA gene variants lead to a structural destabilization and subsequent proteasomal degradation of the ASPA protein variants, and accordingly Canavan disease should in general be considered a protein misfolding disorder. Here, we comprehensively summarize the molecular and cell biology of ASPA, with a particular focus on disease-linked gene variants and the pathophysiology of Canavan disease. We highlight the importance of high-throughput technologies and computational prediction tools for making genotype-phenotype predictions as we await the results of ongoing trials with gene therapy for Canavan disease.
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Affiliation(s)
- Martin Grønbæk-Thygesen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200N, Copenhagen, Denmark.
| | - Rasmus Hartmann-Petersen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200N, Copenhagen, Denmark.
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2
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Wu Q, Zhou X, Wang Y, Hu Y. LncRNA GAS5 promotes spermidine‑induced autophagy through the miRNA‑31‑5p/NAT8L axis in pulmonary artery endothelial cells of patients with CTEPH. Mol Med Rep 2022; 26:297. [PMID: 35920180 PMCID: PMC9434988 DOI: 10.3892/mmr.2022.12813] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/23/2021] [Indexed: 11/17/2022] Open
Abstract
Chronic thromboembolic pulmonary hypertension (CTEPH) is a leading cause of pulmonary hypertension. The present study investigated the mechanisms of long non-coding RNA growth arrest-specific transcript 5 (GAS5) on spermidine (SP)-induced autophagy. Pulmonary artery endothelial cells (PAECs) were collected from patients with CTEPH and the rat model. Immunofluorescence, Western blots, reverse transcription-quantitative polymerase chain reaction, bioinformatics, rapid amplification of cDNA ends assays, luciferase reporter assays, RNA-binding protein immunoprecipitation assays, GFP-LC3 adenoviruses, tfLC3 assays and transmission electron microscopy were performed. The results revealed that SP-induced autophagy increased GAS5 in PAECs. The upregulation of GAS5 enhanced and the downregulation of GAS5 reversed the roles of SP in PAECs. Furthermore, GAS5 promoted SP-induced autophagy in PAECs by targeting miRNA-31-5p. The miRNA-31-5p mimic suppressed and the inhibitor promoted SP-induced autophagy. Furthermore, N-Acetyltransferase 8 Like (NAT8L) was a target gene of miRNA-31-5p and knockdown of NAT8L inhibited the autophagic levels of PAECs. In vivo, SP treatment decreased miRNA-31-5p and increased NAT8L levels, which was reversed by the knockdown of GAS5. The downregulation of GAS5 abolished the stimulatory role of SP in PAECs of CTEPH rats. In conclusion, GAS5 promoted SP-induced autophagy through miRNA-31-5p/NAT8L signaling pathways in vitro and in vivo and GAS5 may be a promising molecular marker for therapies of CTEPH.
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Affiliation(s)
- Qinghua Wu
- Department of Cardiovascular Medicine, Cangzhou Central Hospital, Cangzhou, Hebei 061001, P.R. China
| | - Xiaohui Zhou
- Department of Cardiovascular Medicine, Cangzhou Central Hospital, Cangzhou, Hebei 061001, P.R. China
| | - Yan Wang
- Department of Cardiovascular Medicine, Cangzhou Central Hospital, Cangzhou, Hebei 061001, P.R. China
| | - Yamin Hu
- Department of Cardiovascular Medicine, Cangzhou Central Hospital, Cangzhou, Hebei 061001, P.R. China
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3
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Wei H, Moffett JR, Amanat M, Fatemi A, Tsukamoto T, Namboodiri AM, Slusher BS. The pathogenesis of, and pharmacological treatment for, Canavan disease. Drug Discov Today 2022; 27:2467-2483. [DOI: 10.1016/j.drudis.2022.05.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/05/2022] [Accepted: 05/24/2022] [Indexed: 12/12/2022]
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4
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Salji MJ, Blomme A, Däbritz JHM, Repiscak P, Lilla S, Patel R, Sumpton D, van den Broek NJ, Daly R, Zanivan S, Leung HY. Multi-omics & pathway analysis identify potential roles for tumor N-acetyl aspartate accumulation in murine models of castration-resistant prostate cancer. iScience 2022; 25:104056. [PMID: 35345457 PMCID: PMC8957019 DOI: 10.1016/j.isci.2022.104056] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 11/10/2021] [Accepted: 03/08/2022] [Indexed: 11/22/2022] Open
Abstract
Castration-resistant prostate cancer (CRPC) is incurable and remains a significant worldwide challenge (Oakes and Papa, 2015). Matched untargeted multi-level omic datasets may reveal biological changes driving CRPC, identifying novel biomarkers and/or therapeutic targets. Untargeted RNA sequencing, proteomics, and metabolomics were performed on xenografts derived from three independent sets of hormone naive and matched CRPC human cell line models of local, lymph node, and bone metastasis grown as murine orthografts. Collectively, we tested the feasibility of muti-omics analysis on models of CRPC in revealing pathways of interest for future validation investigation. Untargeted metabolomics revealed NAA and NAAG commonly accumulating in CRPC across three independent models and proteomics showed upregulation of related enzymes, namely N-acetylated alpha-linked acidic dipeptidases (FOLH1/NAALADL2). Based on pathway analysis integrating multiple omic levels, we hypothesize that increased NAA in CRPC may be due to upregulation of NAAG hydrolysis via NAALADLases providing a pool of acetyl Co-A for upregulated sphingolipid metabolism and a pool of glutamate and aspartate for nucleotide synthesis during tumor growth.
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Affiliation(s)
- Mark J. Salji
- Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden, Glasgow G61 1QH, UK
- CRUK Beatson Institute, Bearsden, Glasgow G61 1BD, UK
| | - Arnaud Blomme
- Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden, Glasgow G61 1QH, UK
- CRUK Beatson Institute, Bearsden, Glasgow G61 1BD, UK
| | - J. Henry M. Däbritz
- Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden, Glasgow G61 1QH, UK
- CRUK Beatson Institute, Bearsden, Glasgow G61 1BD, UK
| | - Peter Repiscak
- Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden, Glasgow G61 1QH, UK
- CRUK Beatson Institute, Bearsden, Glasgow G61 1BD, UK
| | - Sergio Lilla
- Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden, Glasgow G61 1QH, UK
- CRUK Beatson Institute, Bearsden, Glasgow G61 1BD, UK
| | - Rachana Patel
- Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden, Glasgow G61 1QH, UK
- CRUK Beatson Institute, Bearsden, Glasgow G61 1BD, UK
| | - David Sumpton
- Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden, Glasgow G61 1QH, UK
- CRUK Beatson Institute, Bearsden, Glasgow G61 1BD, UK
| | - Niels J.F. van den Broek
- Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden, Glasgow G61 1QH, UK
- CRUK Beatson Institute, Bearsden, Glasgow G61 1BD, UK
| | - Ronan Daly
- Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden, Glasgow G61 1QH, UK
- CRUK Beatson Institute, Bearsden, Glasgow G61 1BD, UK
| | - Sara Zanivan
- Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden, Glasgow G61 1QH, UK
- CRUK Beatson Institute, Bearsden, Glasgow G61 1BD, UK
| | - Hing Y. Leung
- Institute of Cancer Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden, Glasgow G61 1QH, UK
- CRUK Beatson Institute, Bearsden, Glasgow G61 1BD, UK
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5
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Magnetic resonance spectroscopic evidence of increased choline in the dorsolateral prefrontal and visual cortices in recent onset schizophrenia. Neurosci Lett 2022; 770:136410. [PMID: 34933057 PMCID: PMC9332487 DOI: 10.1016/j.neulet.2021.136410] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 11/09/2021] [Accepted: 12/15/2021] [Indexed: 12/30/2022]
Abstract
A complete characterization of neurometabolite profiles in the dorsolateral prefrontal cortex (DLPFC) in recent onset schizophrenia (SZ) remains elusive. Filling in this knowledge gap is essential in order to better understand how the neurochemistry of this region contributes to SZ pathology. To that end, DLPFC N-acetyl aspartate (NAA), myo-inositol, glutamate, choline, and creatine levels were examined by 3 T magnetic resonance spectroscopy (MRS) in recent onset individuals with SZ (n = 40) and healthy controls (HC) (n = 47). Metabolite levels were also examined in the visual cortex (VC) as a control region. People with SZ showed significantly higher choline in both the DLPFC and VC, but no differences in NAA, myo-inositol, glutamate, or creatine in either region. A trend-level negative correlation was also observed between DLPFC NAA and negative symptoms in SZ. Our results suggest that choline is increased in both the prefrontal and occipital cortices in recent onset SZ, and that DLPFC NAA levels may be inversely related to negative symptoms in the illness. The observed increase in choline-containing compounds in both DLPFC and VC in recent onset SZ could reflect increased membrane remodeling such as occurs in activated microglia and astrocytes in response to neuroinflammation.
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Hsu CH, Lin S, Ho AC, Johnson TD, Wang PC, Scafidi J, Tu TW. Comparison of in vivo and in situ detection of hippocampal metabolites in mouse brain using 1 H-MRS. NMR IN BIOMEDICINE 2021; 34:e4451. [PMID: 33258202 PMCID: PMC8214416 DOI: 10.1002/nbm.4451] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 10/04/2020] [Accepted: 11/06/2020] [Indexed: 05/25/2023]
Abstract
The study of cerebral metabolites relies heavily on detection methods and sample preparation. Animal experiments in vivo require anesthetic agents that can alter brain metabolism, whereas ex vivo experiments demand appropriate fixation methods to preserve the tissue from rapid postmortem degradation. In this study, the metabolic profiles of mouse hippocampi using proton magnetic resonance spectroscopy (1 H-MRS) were compared in vivo and in situ with or without focused beam microwave irradiation (FBMI) fixation. Ten major brain metabolites, including lactate (Lac), N-acetylaspartate (NAA), total choline (tCho), myo-inositol (mIns), glutamine (Gln), glutamate (Glu), aminobutyric acid (GABA), glutathione (GSH), total creatine (tCr) and taurine (Tau), were analyzed using LCModel. After FBMI fixation, the concentrations of Lac, tCho and mIns were comparable with those obtained in vivo under isoflurane, whereas other metabolites were significantly lower. Except for a decrease in NAA and an increase in Tau, all the other metabolites remained stable over 41 hours in FBMI-fixed brains. Without FBMI, the concentrations of mIns (before 2 hours), tCho and GABA were close to those measured in vivo. However, higher Lac (P < .01) and lower NAA, Gln, Glu, GSH, tCr and Tau were observed (P < .01). NAA, Gln, Glu, GSH, tCr and Tau exhibited good temporal stability for at least 20 hours in the unfixed brain, whereas a linear increase of tCho, mIns and GABA was observed. Possible mechanisms of postmortem degradation are discussed. Our results indicate that a proper fixation method is required for in situ detection depending on the targeted metabolites of specific interests in the brain.
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Affiliation(s)
- Chao-Hsiung Hsu
- Molecular Imaging Laboratory, Department of Radiology, Howard University, Washington, DC, USA
| | - Stephen Lin
- Molecular Imaging Laboratory, Department of Radiology, Howard University, Washington, DC, USA
| | - Ai-Chen Ho
- Molecular Imaging Laboratory, Department of Radiology, Howard University, Washington, DC, USA
- Department of Pharmacotherapy and Outcomes Science, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA
| | - T. Derek Johnson
- Center for Neuroscience Research, Department of Neurology, Children’s National Hospital, Washington, DC, USA
| | - Paul C. Wang
- Molecular Imaging Laboratory, Department of Radiology, Howard University, Washington, DC, USA
- Department of Electrical Engineering, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Joseph Scafidi
- Center for Neuroscience Research, Department of Neurology, Children’s National Hospital, Washington, DC, USA
| | - Tsang-Wei Tu
- Molecular Imaging Laboratory, Department of Radiology, Howard University, Washington, DC, USA
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7
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Stecula A, Hussain MS, Viola RE. Discovery of Novel Inhibitors of a Critical Brain Enzyme Using a Homology Model and a Deep Convolutional Neural Network. J Med Chem 2020; 63:8867-8875. [DOI: 10.1021/acs.jmedchem.0c00473] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Adrian Stecula
- Atomwise Inc., San Francisco, California 94103, United States
| | - Muhammad S. Hussain
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606, United States
| | - Ronald E. Viola
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606, United States
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8
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Hofer DC, Zirkovits G, Pelzmann HJ, Huber K, Pessentheiner AR, Xia W, Uno K, Miyazaki T, Kon K, Tsuneki H, Pendl T, Al Zoughbi W, Madreiter-Sokolowski CT, Trausinger G, Abdellatif M, Schoiswohl G, Schreiber R, Eisenberg T, Magnes C, Sedej S, Eckhardt M, Sasahara M, Sasaoka T, Nitta A, Hoefler G, Graier WF, Kratky D, Auwerx J, Bogner-Strauss JG. N-acetylaspartate availability is essential for juvenile survival on fat-free diet and determines metabolic health. FASEB J 2019; 33:13808-13824. [PMID: 31638418 PMCID: PMC6894082 DOI: 10.1096/fj.201801323r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/10/2019] [Indexed: 12/15/2022]
Abstract
N-acetylaspartate (NAA) is synthesized by aspartate N-acetyltransferase (gene: Nat8l) from acetyl-coenzyme A and aspartate. In the brain, NAA is considered an important energy metabolite for lipid synthesis. However, the role of NAA in peripheral tissues remained elusive. Therefore, we characterized the metabolic phenotype of knockout (ko) and adipose tissue-specific (ako) Nat8l-ko mice as well as NAA-supplemented mice on various diets. We identified an important role of NAA availability in the brain during adolescence, as 75% of Nat8l-ko mice died on fat-free diet (FFD) after weaning but could be rescued by NAA supplementation. In adult life, NAA deficiency promotes a beneficial metabolic phenotype, as Nat8l-ko and Nat8l-ako mice showed reduced body weight, increased energy expenditure, and improved glucose tolerance on chow, high-fat, and FFDs. Furthermore, Nat8l-deficient adipocytes exhibited increased mitochondrial respiration, ATP synthesis, and an induction of browning. Conversely, NAA-treated wild-type mice showed reduced adipocyte respiration and lipolysis and increased de novo lipogenesis, culminating in reduced energy expenditure, glucose tolerance, and insulin sensitivity. Mechanistically, our data point to a possible role of NAA as modulator of pancreatic insulin secretion and suggest NAA as a critical energy metabolite for adipocyte and whole-body energy homeostasis.-Hofer, D. C., Zirkovits, G., Pelzmann, H. J., Huber, K., Pessentheiner, A. R., Xia, W., Uno, K., Miyazaki, T., Kon, K., Tsuneki, H., Pendl, T., Al Zoughbi, W., Madreiter-Sokolowski, C. T., Trausinger, G., Abdellatif, M., Schoiswohl, G., Schreiber, R., Eisenberg, T., Magnes, C., Sedej, S., Eckhardt, M., Sasahara, M., Sasaoka, T., Nitta, A., Hoefler, G., Graier, W. F., Kratky, D., Auwerx, J., Bogner-Strauss, J. G. N-acetylaspartate availability is essential for juvenile survival on fat-free diet and determines metabolic health.
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Affiliation(s)
- Dina C. Hofer
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Laboratory of Integrative and Systems Physiology, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Gabriel Zirkovits
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Helmut J. Pelzmann
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Fresenius Kabi Austria GmbH, Graz, Austria
| | - Katharina Huber
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Ariane R. Pessentheiner
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Department of Medicine, University of California–San Diego, La Jolla, California, USA
| | - Wenmin Xia
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Kyosuke Uno
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Toh Miyazaki
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Kanta Kon
- Department of Clinical Pharmacology, University of Toyama, Toyama, Japan
| | - Hiroshi Tsuneki
- Department of Clinical Pharmacology, University of Toyama, Toyama, Japan
| | - Tobias Pendl
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
| | - Wael Al Zoughbi
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | | | - Gert Trausinger
- Joanneum Research, HEALTH–Institute for Biomedicine and Health Sciences, Graz, Austria
| | | | | | - Renate Schreiber
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Tobias Eisenberg
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Christoph Magnes
- Joanneum Research, HEALTH–Institute for Biomedicine and Health Sciences, Graz, Austria
| | - Simon Sedej
- Department of Cardiology, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Matthias Eckhardt
- Institute of Biochemistry and Molecular Biology, University of Bonn, Bonn, Germany
| | | | - Toshiyasu Sasaoka
- Department of Clinical Pharmacology, University of Toyama, Toyama, Japan
| | - Atsumi Nitta
- Department of Pharmaceutical Therapy and Neuropharmacology, Faculty of Pharmaceutical Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Gerald Hoefler
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Wolfgang F. Graier
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Johan Auwerx
- Laboratory of Integrative and Systems Physiology, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Juliane G. Bogner-Strauss
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- BioTechMed-Graz, Graz, Austria
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Osier ND, Ziari M, Puccio AM, Poloyac S, Okonkwo DO, Minnigh MB, Beers SR, Conley YP. Elevated cerebrospinal fluid concentrations of N-acetylaspartate correlate with poor outcome in a pilot study of severe brain trauma. Brain Inj 2019; 33:1364-1371. [PMID: 31305157 PMCID: PMC6675639 DOI: 10.1080/02699052.2019.1641743] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 07/06/2019] [Indexed: 10/26/2022]
Abstract
Primary objective: Examine the correlation between acute cerebrospinal fluid (CSF) levels of N-acetylaspartate (NAA) and injury severity upon admission in addition to long-term functional outcomes of severe traumatic brain injury (TBI). Design and rationale: This exploratory study assessed CSF NAA levels in the first four days after severe TBI, and correlated these findings with Glasgow Coma Scale (GCS) score and long-term outcomes at 3, 6, 12, and 24 months post-injury. Methods: CSF was collected after passive drainage via an indwelling ventriculostomy placed as standard of care in a total of 28 people with severe TBI. NAA levels were assayed using triple quadrupole mass spectrometry. Functional outcomes were assessed using the Glasgow Outcomes Scale (GOS) and Disability Rating Scale (DRS). Results: In this pilot study, better functional outcomes, assessed using the GOS and DRS, were found in individuals with lower acute CSF NAA levels after TBI. Key findings were that average NAA level was associated with GCS (p = .02), and GOS at 3 (p = .01), 6 (p = .04), 12 (p = .007), and 24 months (p = .002). Implications: The results of this study add to a growing body of neuroimaging evidence that raw NAA values are reduced and variable after TBI, potentially impacting patient outcomes, warranting additional exploration into this finding. This line of inquiry could lead to improved diagnosis and prognosis in patients with TBI.
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Affiliation(s)
- Nicole D Osier
- a School of Nursing, University of Texas at Austin , Austin , Texas , USA
- b Department of Neurology, University of Texas at Austin , Austin , Texas , USA
| | - Melody Ziari
- c College of Natural Sciences, University of Texas at Austin , Austin , Texas , USA
| | - Ava M Puccio
- d Department of Neurological Surgery, University of Pittsburgh , Pittsburgh , Pennsylvania , USA
| | - Samuel Poloyac
- e School of Pharmacy, University of Pittsburgh , Pittsburgh , Pennsylvania , USA
| | - David O Okonkwo
- d Department of Neurological Surgery, University of Pittsburgh , Pittsburgh , Pennsylvania , USA
| | - Margaret B Minnigh
- e School of Pharmacy, University of Pittsburgh , Pittsburgh , Pennsylvania , USA
| | - Sue R Beers
- f Department of Psychiatry, University of Pittsburgh , Pittsburgh , Pennsylvania , USA
| | - Yvette P Conley
- g School of Nursing, University of Pittsburgh , Pittsburgh , Pennsylvania , USA
- h Department of Human Genetics, University of Pittsburgh , Pittsburgh , Pennsylvania , USA
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10
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Huber K, Hofer DC, Trefely S, Pelzmann HJ, Madreiter-Sokolowski C, Duta-Mare M, Schlager S, Trausinger G, Stryeck S, Graier WF, Kolb D, Magnes C, Snyder NW, Prokesch A, Kratky D, Madl T, Wellen KE, Bogner-Strauss JG. N-acetylaspartate pathway is nutrient responsive and coordinates lipid and energy metabolism in brown adipocytes. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2019; 1866:337-348. [PMID: 30595160 PMCID: PMC6390944 DOI: 10.1016/j.bbamcr.2018.08.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 08/27/2018] [Indexed: 12/22/2022]
Abstract
The discovery of significant amounts of metabolically active brown adipose tissue (BAT) in adult humans renders it a promising target for anti-obesity therapies by inducing weight loss through increased energy expenditure. The components of the N-acetylaspartate (NAA) pathway are highly abundant in BAT. Aspartate N-acetyltransferase (Asp-NAT, encoded by Nat8l) synthesizes NAA from acetyl-CoA and aspartate and increases energy expenditure in brown adipocytes. However, the exact mechanism how the NAA pathway contributes to accelerated mobilization and oxidation of lipids and the physiological regulation of the NAA pathway remained elusive. Here, we demonstrate that the expression of NAA pathway genes corresponds to nutrient availability and specifically responds to changes in exogenous glucose. NAA is preferentially produced from glucose-derived acetyl-CoA and aspartate and its concentration increases during adipogenesis. Overexpression of Nat8l drains glucose-derived acetyl-CoA into the NAA pool at the expense of cellular lipids and certain amino acids. Mechanistically, we elucidated that a combined activation of neutral and lysosomal (acid) lipolysis is responsible for the increased lipid degradation. Specifically, translocation of the transcription factor EB to the nucleus activates the biosynthesis of autophagosomes and lysosomes. Lipid degradation within lysosomes accompanied by adipose triglyceride lipase-mediated lipolysis delivers fatty acids for the support of elevated mitochondrial respiration. Together, our data suggest a crucial role of the NAA pathway in energy metabolism and metabolic adaptation in BAT.
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Affiliation(s)
- Katharina Huber
- Institute of Biochemistry, Graz University of Technology, Graz, Austria; Department of Cancer Biology, University of Pennsylvania, Philadelphia, USA; Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, USA
| | - Dina C Hofer
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Sophie Trefely
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, USA; Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, USA; AJ Drexel Autism Institute, Drexel University, Philadelphia, USA
| | - Helmut J Pelzmann
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Corina Madreiter-Sokolowski
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Madalina Duta-Mare
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Stefanie Schlager
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Gert Trausinger
- HEALTH Institute for Biomedicine and Health Sciences, Joanneum Research, Graz, Austria
| | - Sarah Stryeck
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Wolfgang F Graier
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Dagmar Kolb
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Histology and Embryology, Medical University of Graz, Graz, Austria
| | - Christoph Magnes
- HEALTH Institute for Biomedicine and Health Sciences, Joanneum Research, Graz, Austria
| | | | - Andreas Prokesch
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Histology and Embryology, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Cell Biology, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Kathryn E Wellen
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, USA; Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, USA
| | - Juliane G Bogner-Strauss
- Institute of Biochemistry, Graz University of Technology, Graz, Austria; BioTechMed-Graz, Graz, Austria.
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11
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Ryan MC, Kochunov P, Sherman PM, Rowland LM, Wijtenburg SA, Acheson A, Hong LE, Sladky J, McGuire S. Miniature pig magnetic resonance spectroscopy model of normal adolescent brain development. J Neurosci Methods 2018; 308:173-182. [PMID: 30099002 DOI: 10.1016/j.jneumeth.2018.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 08/07/2018] [Accepted: 08/08/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND We are developing the miniature pig (Sus scrofa domestica), an in-vivo translational, gyrencephalic model for brain development, as an alternative to laboratory rodents/non-human primates. We analyzed longitudinal changes in adolescent pigs using proton magnetic resonance spectroscopy (1H-MRS) and examined the relationship with white matter (WM) integrity derived from diffusion weighted imaging (DWI). NEW METHOD Twelve female Sinclair™ pigs underwent three imaging/spectroscopy sessions every 23.95 ± 3.73 days beginning at three months of age using a clinical 3 T scanner. 1H-MRS data were collected using 1.2 × 1.0 × 3.0 cm voxels placed in left and right hemisphere WM using a Point Resolved Spectroscopy sequence (TR = 2000 ms, TE = 30 ms). Concentrations of N-acetylaspartate, myo-inositol (MI), glutamate + glutamine, choline, creatine, and macromolecules (MM) 09 and 14 were averaged from both hemispheres. DWI data were collected using 15 shells of b-values (b = 0-3500 s/mm2) with 32 directions/shell and fit using the WM Tract Integrity model to calculate fractional anisotropy (FA), kurtosis anisotropy (KA) and permeability-diffusivity index. RESULTS MI and MM09 significantly declined with age. Increased FA and KA significantly correlated with decline in MI and MM09. Correlations lost significance once corrected for age. COMPARISON WITH EXISTING METHODS MRI scanners/protocols can be used to collect 1H-MRS and DWI data in pigs. Pigs have a larger, more complex, gyrencephalic brain than laboratory rodents but are less complex than non-human primates, thus satisfying the "replacement" principle of animal research. CONCLUSIONS Longitudinal effects in MRS measurements were similar to those reported in adolescent humans. MRS changes correlated with diffusion measurements indicating ongoing WM myelination/maturation.
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Affiliation(s)
- Meghann C Ryan
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, 55 Wade Avenue, Catonsville, MD 21228, United States.
| | - Peter Kochunov
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, 55 Wade Avenue, Catonsville, MD 21228, United States.
| | - Paul M Sherman
- U.S. Air Force School of Aerospace Medicine, Aeromedical Research Department, 2510 5th Street, Building 840, Wright-Patterson AFB, OH 45433-7913, United States; Department of Radiology, 59thMedical Wing, 1100 Wilford Hall Loop, Bldg 4551, Joint Base San Antonio, TX, 78236, United States.
| | - Laura M Rowland
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, 55 Wade Avenue, Catonsville, MD 21228, United States.
| | - S Andrea Wijtenburg
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, 55 Wade Avenue, Catonsville, MD 21228, United States.
| | - Ashley Acheson
- Department of Psychiatry, University of Arkansas for Medical Sciences, 4301 W Markham St., Little Rock, AR, 72205, United States.
| | - L Elliot Hong
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, 55 Wade Avenue, Catonsville, MD 21228, United States.
| | - John Sladky
- U.S. Air Force School of Aerospace Medicine, Aeromedical Research Department, 2510 5th Street, Building 840, Wright-Patterson AFB, OH 45433-7913, United States; Department of Neurology, 59th Medical Wing, 1100 Wilford Hall Loop, Bldg 4551, Joint Base San Antonio, Lackland AFB, TX, 78236, United States.
| | - Stephen McGuire
- Department of Neurology, University of Texas Health Science Center San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, United States.
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12
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Dervishi E, Zhang G, Hailemariam D, Mandal R, Wishart DS, Ametaj BN. Urine metabolic fingerprinting can be used to predict the risk of metritis and highlight the pathobiology of the disease in dairy cows. Metabolomics 2018; 14:83. [PMID: 30830348 DOI: 10.1007/s11306-018-1379-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 06/02/2018] [Indexed: 01/19/2023]
Abstract
INTRODUCTION Metritis is an uterine pathology that causes economic losses for the dairy industry. It is associated with lower reproductive efficiency, increased culling rates, decreased milk production and increased veterinary costs. OBJECTIVES To gain a more detailed view of the urine metabolome and to detect metabolite signature in cows with metritis. In addition, we aimed to identify early metabolites which can help to detect cows at risk to develop metritis in the future. METHODS We used nuclear magnetic resonance spectroscopy starting at 8 and 4 weeks prior to the expected day of parturition, during the week of diagnosis of metritis, and at 4 and 8 weeks after diagnosis of metritis in Holstein dairy cows. RESULTS At 8 weeks before parturition, pre-metritic cows had a total of 30 altered metabolites. Interestingly, 28 of them increased in urine when compared with control cows (P < 0.05). At 4 weeks before parturition, 34 metabolites were altered. At the week of diagnosis of metritis a total of 20 metabolites were altered (P < 0.05). The alteration continued at 4 and 8 weeks after diagnosis. CONCLUSIONS The metabolic fingerprints in the urine of pre-metritic and metritic cows point toward excretion of multiple amino acids, tricarboxylic acid cycle metabolites and monosaccharides. Combination of galactose, leucine, lysine and panthotenate at 8 weeks before parturition might serve as predictive biomarkers for metritis.
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Affiliation(s)
- E Dervishi
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada.
| | - G Zhang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
- Departments of Biological Sciences and Computing Science, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - D Hailemariam
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
| | - R Mandal
- Departments of Biological Sciences and Computing Science, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - D S Wishart
- Departments of Biological Sciences and Computing Science, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - B N Ametaj
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada
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13
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Williams NC, O'Neill LAJ. A Role for the Krebs Cycle Intermediate Citrate in Metabolic Reprogramming in Innate Immunity and Inflammation. Front Immunol 2018; 9:141. [PMID: 29459863 PMCID: PMC5807345 DOI: 10.3389/fimmu.2018.00141] [Citation(s) in RCA: 363] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 01/16/2018] [Indexed: 12/13/2022] Open
Abstract
Metabolism in immune cells is no longer thought of as merely a process for adenosine triphosphate (ATP) production, biosynthesis, and catabolism. The reprogramming of metabolic pathways upon activation is also for the production of metabolites that can act as immune signaling molecules. Activated dendritic cells (DCs) and macrophages have an altered Krebs cycle, one consequence of which is the accumulation of both citrate and succinate. Citrate is exported from the mitochondria via the mitochondrial citrate- carrier. Cytosolic metabolism of citrate to acetyl-coenzyme A (acetyl-CoA) is important for both fatty-acid synthesis and protein acetylation, both of which have been linked to macrophage and DC activation. Citrate-derived itaconate has a direct antibacterial effect and also has been shown to act as an anti-inflammatory agent, inhibiting succinate dehydrogenase. These findings identify citrate as an important metabolite for macrophage and DC effector function.
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Affiliation(s)
- Niamh C Williams
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Luke A J O'Neill
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
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14
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Uncoupling N-acetylaspartate from brain pathology: implications for Canavan disease gene therapy. Acta Neuropathol 2018; 135:95-113. [PMID: 29116375 PMCID: PMC5756261 DOI: 10.1007/s00401-017-1784-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Revised: 10/31/2017] [Accepted: 11/01/2017] [Indexed: 11/25/2022]
Abstract
N-Acetylaspartate (NAA) is the second most abundant organic metabolite in the brain, but its physiological significance remains enigmatic. Toxic NAA accumulation appears to be the key factor for neurological decline in Canavan disease—a fatal neurometabolic disorder caused by deficiency in the NAA-degrading enzyme aspartoacylase. To date clinical outcome of gene replacement therapy for this spongiform leukodystrophy has not met expectations. To identify the target tissue and cells for maximum anticipated treatment benefit, we employed comprehensive phenotyping of novel mouse models to assess cell type-specific consequences of NAA depletion or elevation. We show that NAA-deficiency causes neurological deficits affecting unconscious defensive reactions aimed at protecting the body from external threat. This finding suggests, while NAA reduction is pivotal to treat Canavan disease, abrogating NAA synthesis should be avoided. At the other end of the spectrum, while predicting pathological severity in Canavan disease mice, increased brain NAA levels are not neurotoxic per se. In fact, in transgenic mice overexpressing the NAA synthesising enzyme Nat8l in neurons, supra-physiological NAA levels were uncoupled from neurological deficits. In contrast, elimination of aspartoacylase expression exclusively in oligodendrocytes elicited Canavan disease like pathology. Although conditional aspartoacylase deletion in oligodendrocytes abolished expression in the entire CNS, the remaining aspartoacylase in peripheral organs was sufficient to lower NAA levels, delay disease onset and ameliorate histopathology. However, comparable endpoints of the conditional and complete aspartoacylase knockout indicate that optimal Canavan disease gene replacement therapies should restore aspartoacylase expression in oligodendrocytes. On the basis of these findings we executed an ASPA gene replacement therapy targeting oligodendrocytes in Canavan disease mice resulting in reversal of pre-existing CNS pathology and lasting neurological benefits. This finding signifies the first successful post-symptomatic treatment of a white matter disorder using an adeno-associated virus vector tailored towards oligodendroglial-restricted transgene expression.
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15
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Appu AP, Moffett JR, Arun P, Moran S, Nambiar V, Krishnan JKS, Puthillathu N, Namboodiri AMA. Increasing N-acetylaspartate in the Brain during Postnatal Myelination Does Not Cause the CNS Pathologies of Canavan Disease. Front Mol Neurosci 2017; 10:161. [PMID: 28626388 PMCID: PMC5454052 DOI: 10.3389/fnmol.2017.00161] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/09/2017] [Indexed: 01/03/2023] Open
Abstract
Canavan disease is caused by mutations in the gene encoding aspartoacylase (ASPA), a deacetylase that catabolizes N-acetylaspartate (NAA). The precise involvement of elevated NAA in the pathogenesis of Canavan disease is an ongoing debate. In the present study, we tested the effects of elevated NAA in the brain during postnatal development. Mice were administered high doses of the hydrophobic methyl ester of NAA (M-NAA) twice daily starting on day 7 after birth. This treatment increased NAA levels in the brain to those observed in the brains of Nur7 mice, an established model of Canavan disease. We evaluated various serological parameters, oxidative stress, inflammatory and neurodegeneration markers and the results showed that there were no pathological alterations in any measure with increased brain NAA levels. We examined oxidative stress markers, malondialdehyde content (indicator of lipid peroxidation), expression of NADPH oxidase and nuclear translocation of the stress-responsive transcription factor nuclear factor (erythroid-derived 2)-like 2 (NRF-2) in brain. We also examined additional pathological markers by immunohistochemistry and the expression of activated caspase-3 and interleukin-6 by Western blot. None of the markers were increased in the brains of M-NAA treated mice, and no vacuoles were observed in any brain region. These results show that ASPA expression prevents the pathologies associated with excessive NAA concentrations in the brain during postnatal myelination. We hypothesize that the pathogenesis of Canavan disease involves not only disrupted NAA metabolism, but also excessive NAA related signaling processes in oligodendrocytes that have not been fully determined and we discuss some of the potential mechanisms.
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Affiliation(s)
- Abhilash P. Appu
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - John R. Moffett
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Peethambaran Arun
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Sean Moran
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Vikram Nambiar
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Jishnu K. S. Krishnan
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Narayanan Puthillathu
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Aryan M. A. Namboodiri
- Department of Anatomy, Physiology and Genetics and Neuroscience Program, Uniformed Services University of the Health SciencesBethesda, MD, United States
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16
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Design and optimization of aspartate N -acetyltransferase inhibitors for the potential treatment of Canavan disease. Bioorg Med Chem 2017; 25:870-885. [DOI: 10.1016/j.bmc.2016.11.060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 11/27/2016] [Accepted: 11/29/2016] [Indexed: 11/19/2022]
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Singhal NK, Huang H, Li S, Clements R, Gadd J, Daniels A, Kooijman EE, Bannerman P, Burns T, Guo F, Pleasure D, Freeman E, Shriver L, McDonough J. The neuronal metabolite NAA regulates histone H3 methylation in oligodendrocytes and myelin lipid composition. Exp Brain Res 2016; 235:279-292. [PMID: 27709268 DOI: 10.1007/s00221-016-4789-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 09/27/2016] [Indexed: 01/01/2023]
Abstract
The neuronal mitochondrial metabolite N-acetylaspartate (NAA) is decreased in the multiple sclerosis (MS) brain. NAA is synthesized in neurons by the enzyme N-acetyltransferase-8-like (NAT8L) and broken down in oligodendrocytes by aspartoacylase (ASPA) into acetate and aspartate. We have hypothesized that NAA links the metabolism of axons with oligodendrocytes to support myelination. To test this hypothesis, we performed lipidomic analyses using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high-performance thin-layer chromatography (HPTLC) to identify changes in myelin lipid composition in postmortem MS brains and in NAT8L knockout (NAT8L-/-) mice which do not synthesize NAA. We found reduced levels of sphingomyelin in MS normal appearing white matter that mirrored decreased levels of NAA. We also discovered decreases in the amounts of sphingomyelin and sulfatide lipids in the brains of NAT8L-/- mice compared to controls. Metabolomic analysis of primary cultures of oligodendrocytes treated with NAA revealed increased levels of α-ketoglutarate, which has been reported to regulate histone demethylase activity. Consistent with this, NAA treatment resulted in alterations in the levels of histone H3 methylation, including H3K4me3, H3K9me2, and H3K9me3. The H3K4me3 histone mark regulates cellular energetics, metabolism, and growth, while H3K9me3 has been linked to alterations in transcriptional repression in developing oligodendrocytes. We also noted the NAA treatment was associated with increases in the expression of genes involved in sulfatide and sphingomyelin synthesis in cultured oligodendrocytes. This is the first report demonstrating that neuronal-derived NAA can signal to the oligodendrocyte nucleus. These data suggest that neuronal-derived NAA signals through epigenetic mechanisms in oligodendrocytes to support or maintain myelination.
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Affiliation(s)
- N K Singhal
- Department of Biological Sciences and School of Biomedical Sciences, Kent State University, Kent, OH, 44242, USA
| | - H Huang
- Department of Chemistry and Biology, University of Akron, Akron, OH, 44325, USA
| | - S Li
- Department of Biological Sciences and School of Biomedical Sciences, Kent State University, Kent, OH, 44242, USA
| | - R Clements
- Department of Biological Sciences and School of Biomedical Sciences, Kent State University, Kent, OH, 44242, USA
| | - J Gadd
- Department of Biological Sciences and School of Biomedical Sciences, Kent State University, Kent, OH, 44242, USA
| | - A Daniels
- Department of Biological Sciences and School of Biomedical Sciences, Kent State University, Kent, OH, 44242, USA
| | - E E Kooijman
- Department of Biological Sciences and School of Biomedical Sciences, Kent State University, Kent, OH, 44242, USA
| | - P Bannerman
- Department of Cell Biology and Human Anatomy, UC Davis School of Medicine, Sacramento, CA, 95817, USA
| | - T Burns
- Department of Neurology, UC Davis School of Medicine, Sacramento, CA, 95817, USA
| | - F Guo
- Department of Neurology, UC Davis School of Medicine, Sacramento, CA, 95817, USA
| | - D Pleasure
- Department of Neurology, UC Davis School of Medicine, Sacramento, CA, 95817, USA
| | - E Freeman
- Department of Biological Sciences and School of Biomedical Sciences, Kent State University, Kent, OH, 44242, USA
| | - L Shriver
- Department of Chemistry and Biology, University of Akron, Akron, OH, 44325, USA
| | - J McDonough
- Department of Biological Sciences and School of Biomedical Sciences, Kent State University, Kent, OH, 44242, USA.
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18
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Francis JS, Wojtas I, Markov V, Gray SJ, McCown TJ, Samulski RJ, Bilaniuk LT, Wang DJ, De Vivo DC, Janson CG, Leone P. N-acetylaspartate supports the energetic demands of developmental myelination via oligodendroglial aspartoacylase. Neurobiol Dis 2016; 96:323-334. [PMID: 27717881 DOI: 10.1016/j.nbd.2016.10.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 09/27/2016] [Accepted: 10/01/2016] [Indexed: 12/13/2022] Open
Abstract
Breakdown of neuro-glial N-acetyl-aspartate (NAA) metabolism results in the failure of developmental myelination, manifest in the congenital pediatric leukodystrophy Canavan disease caused by mutations to the sole NAA catabolizing enzyme aspartoacylase. Canavan disease is a major point of focus for efforts to define NAA function, with available evidence suggesting NAA serves as an acetyl donor for fatty acid synthesis during myelination. Elevated NAA is a diagnostic hallmark of Canavan disease, which contrasts with a broad spectrum of alternative neurodegenerative contexts in which levels of NAA are inversely proportional to pathological progression. Recently generated data in the nur7 mouse model of Canavan disease suggests loss of aspartoacylase function results in compromised energetic integrity prior to oligodendrocyte death, abnormalities in myelin content, spongiform degeneration, and motor deficit. The present study utilized a next-generation "oligotropic" adeno-associated virus vector (AAV-Olig001) to quantitatively assess the impact of aspartoacylase reconstitution on developmental myelination. AAV-Olig001-aspartoacylase promoted normalization of NAA, increased bioavailable acetyl-CoA, and restored energetic balance within a window of postnatal development preceding gross histopathology and deteriorating motor function. Long-term effects included increased oligodendrocyte numbers, a global increase in myelination, reversal of vacuolation, and rescue of motor function. Effects on brain energy observed following AAV-Olig001-aspartoacylase gene therapy are shown to be consistent with a metabolic profile observed in mild cases of Canavan disease, implicating NAA in the maintenance of energetic integrity during myelination via oligodendroglial aspartoacylase.
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Affiliation(s)
- Jeremy S Francis
- Department of Cell Biology, Cell & Gene Therapy Center, Rowan School of Osteopathic Medicine, Stratford, NJ, USA
| | - Ireneusz Wojtas
- Department of Cell Biology, Cell & Gene Therapy Center, Rowan School of Osteopathic Medicine, Stratford, NJ, USA
| | - Vladimir Markov
- Department of Cell Biology, Cell & Gene Therapy Center, Rowan School of Osteopathic Medicine, Stratford, NJ, USA
| | - Steven J Gray
- Department of Ophthalmology, UNC, Chapel Hill, NC, USA
| | | | - R Jude Samulski
- Department of Pharmacology and Gene Therapy Center, UNC, Chapel Hill, NC, USA
| | - Larissa T Bilaniuk
- Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Dah-Jyuu Wang
- Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | | | - Christopher G Janson
- Department of Neurology & Rehabilitation, University of Illinois at Chicago, Chicago, USA
| | - Paola Leone
- Department of Cell Biology, Cell & Gene Therapy Center, Rowan School of Osteopathic Medicine, Stratford, NJ, USA.
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Cameron AM, Lawless SJ, Pearce EJ. Metabolism and acetylation in innate immune cell function and fate. Semin Immunol 2016; 28:408-416. [PMID: 28340958 PMCID: PMC10911065 DOI: 10.1016/j.smim.2016.10.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 10/10/2016] [Accepted: 10/12/2016] [Indexed: 11/29/2022]
Abstract
Innate immunity is the first line of defense against invading pathogens. Changes in both metabolism and chromatin accessibility contribute to the shaping of these innate immune responses, and we are beginning to appreciate that cross-talk between these two systems plays an important role in determining innate immune cell differentiation and function. In this review we focus on acetylation, a post-translational modification important for both regulating chromatin accessibility by modulating histone function, and for functional regulation of non-histone proteins, which has many links to both immune signaling and metabolism. We discuss the interactions between metabolism and acetylation, including the requirement for metabolic intermediates as substrates and co-factors for acetylation, and the regulation of metabolic proteins and enzymes by acetylation. Here we highlight recent findings, which demonstrate the role that the metabolism-acetylation axis has in coordinating the responses of innate immune cells to the availability of nutrients and the microenvironment.
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Affiliation(s)
- Alanna M Cameron
- Department of Immunometabolism, Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
| | - Simon J Lawless
- Department of Immunometabolism, Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany
| | - Edward J Pearce
- Department of Immunometabolism, Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany.
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20
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Wynn ML, Yates JA, Evans CR, Van Wassenhove LD, Wu ZF, Bridges S, Bao L, Fournier C, Ashrafzadeh S, Merrins MJ, Satin LS, Schnell S, Burant CF, Merajver SD. RhoC GTPase Is a Potent Regulator of Glutamine Metabolism and N-Acetylaspartate Production in Inflammatory Breast Cancer Cells. J Biol Chem 2016; 291:13715-29. [PMID: 27129239 PMCID: PMC4919454 DOI: 10.1074/jbc.m115.703959] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 04/01/2016] [Indexed: 01/04/2023] Open
Abstract
Inflammatory breast cancer (IBC) is an extremely lethal cancer that rapidly metastasizes. Although the molecular attributes of IBC have been described, little is known about the underlying metabolic features of the disease. Using a variety of metabolic assays, including (13)C tracer experiments, we found that SUM149 cells, the primary in vitro model of IBC, exhibit metabolic abnormalities that distinguish them from other breast cancer cells, including elevated levels of N-acetylaspartate, a metabolite primarily associated with neuronal disorders and gliomas. Here we provide the first evidence of N-acetylaspartate in breast cancer. We also report that the oncogene RhoC, a driver of metastatic potential, modulates glutamine and N-acetylaspartate metabolism in IBC cells in vitro, revealing a novel role for RhoC as a regulator of tumor cell metabolism that extends beyond its well known role in cytoskeletal rearrangement.
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Affiliation(s)
- Michelle L Wynn
- From the Departments of Internal Medicine, Molecular and Integrative Physiology, and
| | | | | | | | - Zhi Fen Wu
- From the Departments of Internal Medicine
| | | | - Liwei Bao
- From the Departments of Internal Medicine
| | | | | | - Matthew J Merrins
- the Department of Medicine, University of Wisconsin, Madison, Wisconsin 53705, and the William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin 53705
| | - Leslie S Satin
- Pharmacology, University of Michigan, Ann Arbor, Michigan 48109
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21
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Ahmed SS, Schattgen SA, Frakes AE, Sikoglu EM, Su Q, Li J, Hampton TG, Denninger AR, Kirschner DA, Kaspar B, Matalon R, Gao G. rAAV Gene Therapy in a Canavan's Disease Mouse Model Reveals Immune Impairments and an Extended Pathology Beyond the Central Nervous System. Mol Ther 2016; 24:1030-1041. [PMID: 27039844 PMCID: PMC4923332 DOI: 10.1038/mt.2016.68] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/25/2016] [Indexed: 02/07/2023] Open
Abstract
Aspartoacylase (AspA) gene mutations cause the pediatric lethal neurodegenerative Canavan disease (CD). There is emerging promise of successful gene therapy for CD using recombinant adeno-associated viruses (rAAVs). Here, we report an intracerebroventricularly delivered AspA gene therapy regime using three serotypes of rAAVs at a 20-fold reduced dose than previously described in AspA(-/-) mice, a bona-fide mouse model of CD. Interestingly, central nervous system (CNS)-restricted therapy prolonged survival over systemic therapy in CD mice but failed to sustain motor functions seen in systemically treated mice. Importantly, we reveal through histological and functional examination of untreated CD mice that AspA deficiency in peripheral tissues causes morphological and functional abnormalities in this heretofore CNS-defined disorder. We demonstrate for the first time that AspA deficiency, possibly through excessive N-acetyl aspartic acid accumulation, elicits both a peripheral and CNS immune response in CD mice. Our data establish a role for peripheral tissues in CD pathology and serve to aid the development of more efficacious and sustained gene therapy for this disease.
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Affiliation(s)
- Seemin Seher Ahmed
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA; Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Stefan A Schattgen
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Ashley E Frakes
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Elif M Sikoglu
- The Center for Comparative Neuroimaging, University of Massachusetts Medical School, Worcester, Massachusetts, USA; Department of Psychiatry, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Qin Su
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Jia Li
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | | | | | | | - Brian Kaspar
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Reuben Matalon
- Department of Pediatrics, Biochemical and Molecular Genetics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Guangping Gao
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA; Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
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Prokesch A, Pelzmann HJ, Pessentheiner AR, Huber K, Madreiter-Sokolowski CT, Drougard A, Schittmayer M, Kolb D, Magnes C, Trausinger G, Graier WF, Birner-Gruenberger R, Pospisilik JA, Bogner-Strauss JG. N-acetylaspartate catabolism determines cytosolic acetyl-CoA levels and histone acetylation in brown adipocytes. Sci Rep 2016; 6:23723. [PMID: 27045997 PMCID: PMC4820693 DOI: 10.1038/srep23723] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/14/2016] [Indexed: 12/15/2022] Open
Abstract
Histone acetylation depends on the abundance of nucleo-cytoplasmic acetyl-CoA. Here, we present a novel route for cytoplasmic acetyl-CoA production in brown adipocytes. N-acetylaspartate (NAA) is a highly abundant brain metabolite catabolized by aspartoacylase yielding aspartate and acetate. The latter can be further used for acetyl-CoA production. Prior to this work, the presence of NAA has not been described in adipocytes. Here, we show that accumulation of NAA decreases the brown adipocyte phenotype. We increased intracellular NAA concentrations in brown adipocytes via media supplementation or knock-down of aspartoacylase and measured reduced lipolysis, thermogenic gene expression, and oxygen consumption. Combinations of approaches to increase intracellular NAA levels showed additive effects on lipolysis and gene repression, nearly abolishing the expression of Ucp1, Cidea, Prdm16, and Ppara. Transcriptome analyses of aspartoacylase knock-down cells indicate deficiencies in acetyl-CoA and lipid metabolism. Concordantly, cytoplasmic acetyl-CoA levels and global histone H3 acetylation were decreased. Further, activating histone marks (H3K27ac and H3K9ac) in promoters/enhancers of brown marker genes showed reduced acetylation status. Taken together, we present a novel route for cytoplasmic acetyl-CoA production in brown adipocytes. Thereby, we mechanistically connect the NAA pathway to the epigenomic regulation of gene expression, modulating the phenotype of brown adipocytes.
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Affiliation(s)
- A. Prokesch
- Institute of Biochemistry, Graz University of Technology, Austria,Institute of Cell Biology, Histology and Embryology, Medical University of Graz, Austria,
| | - H. J. Pelzmann
- Institute of Biochemistry, Graz University of Technology, Austria
| | | | - K. Huber
- Institute of Biochemistry, Graz University of Technology, Austria
| | | | - A. Drougard
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - M. Schittmayer
- Research Unit Functional Proteomics and Metabolic Pathways, Institute of Pathology, Medical University of Graz and Omics Center Graz, BioTechMed-Graz, Austria
| | - D. Kolb
- Institute of Cell Biology, Histology and Embryology, Medical University of Graz, Austria,ZMF, Center for Medical Research, Medical University of Graz, Austria
| | - C. Magnes
- HEALTH Insitute for Biomedicine and Health Sciences, Joanneum Research, Graz, Austria
| | - G. Trausinger
- HEALTH Insitute for Biomedicine and Health Sciences, Joanneum Research, Graz, Austria
| | - W. F. Graier
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, Austria
| | - R. Birner-Gruenberger
- Research Unit Functional Proteomics and Metabolic Pathways, Institute of Pathology, Medical University of Graz and Omics Center Graz, BioTechMed-Graz, Austria
| | - J. A. Pospisilik
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
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23
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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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24
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Wright AD, Jarrett M, Vavasour I, Shahinfard E, Kolind S, van Donkelaar P, Taunton J, Li D, Rauscher A. Myelin Water Fraction Is Transiently Reduced after a Single Mild Traumatic Brain Injury--A Prospective Cohort Study in Collegiate Hockey Players. PLoS One 2016; 11:e0150215. [PMID: 26913900 PMCID: PMC4767387 DOI: 10.1371/journal.pone.0150215] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 02/10/2016] [Indexed: 12/12/2022] Open
Abstract
Impact-related mild traumatic brain injuries (mTBI) are a major public health concern, and remain as one of the most poorly understood injuries in the field of neuroscience. Currently, the diagnosis and management of such injuries are based largely on patient-reported symptoms. An improved understanding of the underlying pathophysiology of mTBI is urgently needed in order to develop better diagnostic and management protocols. Specifically, dynamic post-injury changes to the myelin sheath in the human brain have not been examined, despite ‘compromised white matter integrity’ often being described as a consequence of mTBI. In this preliminary cohort study, myelin water imaging was used to prospectively evaluate changes in myelin water fraction, derived from the T2 decay signal, in two varsity hockey teams (45 players) over one season of athletic competition. 11 players sustained a concussion during competition, and were scanned at 72 hours, 2 weeks, and 2 months post-injury. Results demonstrated a reduction in myelin water fraction at 2 weeks post-injury in several brain areas relative to preseason scans, including the splenium of the corpus callosum, right posterior thalamic radiation, left superior corona radiata, left superior longitudinal fasciculus, and left posterior limb of the internal capsule. Myelin water fraction recovered to pre-season values by 2 months post-injury. These results may indicate transient myelin disruption following a single mTBI, with subsequent remyelination of affected neurons. Myelin disruption was not apparent in the athletes who did not experience a concussion, despite exposure to repetitive subconcussive trauma over a season of collegiate hockey. These findings may help to explain many of the metabolic and neurological deficits observed clinically following mTBI.
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Affiliation(s)
- Alexander D. Wright
- MD/PhD Program, University of British Columbia, Vancouver, Canada
- Southern Medical Program, University of British Columbia Okanagan, Kelowna, Canada
- Department of Experimental Medicine, University of British Columbia, Vancouver, Canada
| | - Michael Jarrett
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
| | - Irene Vavasour
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
| | - Elham Shahinfard
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
| | - Shannon Kolind
- Faculty of Medicine, Division of Neurology, University of British Columbia, Vancouver, Canada
| | - Paul van Donkelaar
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, Canada
| | - Jack Taunton
- Faculty of Medicine, Division of Sports Medicine, University of British Columbia, Vancouver, Canada
| | - David Li
- Faculty of Medicine, Department of Radiology, University of British Columbia, Vancouver, Canada
| | - Alexander Rauscher
- UBC MRI Research Centre, University of British Columbia, Vancouver, Canada
- Department of Pediatrics, Division of Neurology, University of British Columbia, Vancouver, Canada
- * E-mail:
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25
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Abstract
The autosomal recessive Canavan disease (CD) is a neurological disorder that begins in infancy. CD is caused by mutations in the gene encoding the ASPA enzyme. It has been reported with high frequency in patients with Jewish ancestry, and with low frequency in non-Jewish patients. This review will shed light on some updates regarding CD prevalence and causative mutations across the Arab World. CD was reported in several Arab countries such as Saudi Arabia, Egypt, Jordan, Yemen, Kuwait, and Tunisia. The population with the highest risk is in Saudi Arabia due the prevalent consanguineous marriage culture. In several studies, four novel mutations were found among Arabian CD patients, including two missense mutations (p.C152R, p.C152W), a 3346bp deletion leading to the removal of exon 3 of the ASPA gene, and an insertion mutation (698insC). Other previously reported mutations, which led to damage in the ASPA enzyme activities found among CD Arab patients are c.530 T>C (p.I177T), c.79G>A (p.G27R), IVS4+1G>T, and a 92kb deletion, which is 7.16kb upstream from the ASPA start site. This review will help in developing customized molecular diagnostic approaches and promoting CD carrier screening in the Arab world in areas where consanguineous marriage is common particularly within Saudi Arabia.
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26
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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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Igarashi H, Suzuki Y, Huber VJ, Ida M, Nakada T. N-acetylaspartate decrease in acute stage of ischemic stroke: a perspective from experimental and clinical studies. Magn Reson Med Sci 2014; 14:13-24. [PMID: 25500779 DOI: 10.2463/mrms.2014-0039] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
N-acetylaspartate (NAA) appears in a prominent peak in proton magnetic resonance spectroscopy ((1)H-MRS) of the brain. Exhibition by NAA of time-dependent attenuation that reflects energy metabolism during the acute stage of cerebral ischemia makes this metabolite a unique biomarker for assessing ischemic stroke. Although magnetic resonance (MR) imaging is a powerful technique for inspecting the pathological changes that occur during ischemic stroke, biomarkers that directly reflect the drastic metabolic changes associated with acute-stage ischemia are strongly warranted for appropriate therapeutic decision-making in daily clinical settings. In this review, we provide a brief overview of NAA metabolism and focus on the use of attenuation in NAA as a means for assessing the pathophysiological changes that occur during the acute stage of ischemic stroke.
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Affiliation(s)
- Hironaka Igarashi
- Center for Integrated Human Brain Science, Brain Research Institute, University of Niigata
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28
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Li S, Clements R, Sulak M, Gregory R, Freeman E, McDonough J. Decreased NAA in gray matter is correlated with decreased availability of acetate in white matter in postmortem multiple sclerosis cortex. Neurochem Res 2014; 38:2385-96. [PMID: 24078261 DOI: 10.1007/s11064-013-1151-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 08/02/2013] [Accepted: 09/05/2013] [Indexed: 01/31/2023]
Abstract
Multiple sclerosis (MS) is an inflammatory neurodegenerative disease of the central nervous system (CNS) which leads to progressive neurological disability. Our previous studies have demonstrated mitochondrial involvement in MS cortical pathology and others have documented decreased levels of the neuronal mitochondrial metabolite N-acetyl aspartate (NAA) in the MS brain. While NAA is synthesized in neurons, it is broken down in oligodendrocytes into aspartate and acetate. The resulting acetate is incorporated into myelin lipids, linking neuronal mitochondrial function to oligodendrocyte-mediated elaboration of myelin lipids in the CNS. In the present study we show that treating human SH-SY5Y neuroblastoma cells with the electron transport chain inhibitor antimycin A decreased levels of NAA as measured by HPLC. To better understand the significance of the relationship between mitochondrial function and levels of NAA and its breakdown product acetate on MS pathology we then quantitated the levels of NAA and acetate in MS and control postmortem tissue blocks. Regardless of lesion status, we observed that levels of NAA were decreased 25 and 32 % in gray matter from parietal and motor cortex in MS, respectively, compared to controls. Acetate levels in adjacent white matter mirrored these decreases as evidenced by the 36 and 45 % reduction in acetate obtained from parietal and motor cortices. These data suggest a novel mechanism whereby mitochondrial dysfunction and reduced NAA levels in neurons may result in compromised myelination by oligodendrocytes due to decreased availability of acetate necessary for the synthesis of myelin lipids.
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29
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Nordengen K, Heuser C, Rinholm JE, Matalon R, Gundersen V. Localisation of N-acetylaspartate in oligodendrocytes/myelin. Brain Struct Funct 2013; 220:899-917. [PMID: 24379086 DOI: 10.1007/s00429-013-0691-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 12/14/2013] [Indexed: 11/29/2022]
Abstract
The role of N-acetylaspartate in the brain is unclear. Here we used specific antibodies against N-acetylaspartate and immunocytochemistry of carbodiimide-fixed adult rodent brain to show that, besides staining of neuronal cell bodies in the grey matter, N-acetylaspartate labelling was present in oligodendrocytes/myelin in white matter tracts. Immunoelectron microscopy of the rat hippocampus showed that N-acetylaspartate was concentrated in the myelin. Also neuronal cell bodies and axons contained significant amounts of N-acetylaspartate, while synaptic elements and astrocytes were low in N-acetylaspartate. Mitochondria in axons and neuronal cell bodies contained higher levels of N-acetylaspartate compared to the cytosol, compatible with synthesis of N-acetylaspartate in mitochondria. In aspartoacylase knockout mice, in which catabolism of N-acetylaspartate is blocked, the levels of N-acetylaspartate were largely increased in oligodendrocytes/myelin. In these mice, the highest myelin concentration of N-acetylaspartate was found in the cerebellum, a region showing overt dysmyelination. In organotypic cortical slice cultures there was no evidence for N-acetylaspartate-induced myelin toxicity, supporting the notion that myelin damage is induced by the lack of N-acetylaspartate for lipid production. Our findings also implicate that N-acetylaspartate signals on magnetic resonance spectroscopy reflect not only vital neurons but also vital oligodendrocytes/myelin.
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Affiliation(s)
- Kaja Nordengen
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, PO Box 1105, 0317, Oslo, Norway
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30
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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: 124] [Impact Index Per Article: 11.3] [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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31
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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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32
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Long PM, Moffett JR, Namboodiri AMA, Viapiano MS, Lawler SE, Jaworski DM. N-acetylaspartate (NAA) and N-acetylaspartylglutamate (NAAG) promote growth and inhibit differentiation of glioma stem-like cells. J Biol Chem 2013; 288:26188-26200. [PMID: 23884408 DOI: 10.1074/jbc.m113.487553] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Metabolic reprogramming is a pathological feature of cancer and a driver of tumor cell transformation. N-Acetylaspartate (NAA) is one of the most abundant amino acid derivatives in the brain and serves as a source of metabolic acetate for oligodendrocyte myelination and protein/histone acetylation or a precursor for the synthesis of the neurotransmitter N-acetylaspartylglutamate (NAAG). NAA and NAAG as well as aspartoacylase (ASPA), the enzyme responsible for NAA degradation, are significantly reduced in glioma tumors, suggesting a possible role for decreased acetate metabolism in tumorigenesis. This study sought to examine the effects of NAA and NAAG on primary tumor-derived glioma stem-like cells (GSCs) from oligodendroglioma as well as proneural and mesenchymal glioblastoma, relative to oligodendrocyte progenitor cells (Oli-Neu). Although the NAA dicarboxylate transporter NaDC3 is primarily thought to be expressed by astrocytes, all cell lines expressed NaDC3 and, thus, are capable of NAA up-take. Treatment with NAA or NAAG significantly increased GSC growth and suppressed differentiation of Oli-Neu cells and proneural GSCs. Interestingly, ASPA was expressed in both the cytosol and nuclei of GSCs and exhibited greatest nuclear immunoreactivity in differentiation-resistant GSCs. Both NAA and NAAG elicited the expression of a novel immunoreactive ASPA species in select GSC nuclei, suggesting differential ASPA regulation in response to these metabolites. Therefore, this study highlights a potential role for nuclear ASPA expression in GSC malignancy and suggests that the use of NAA or NAAG is not an appropriate therapeutic approach to increase acetate bioavailability in glioma. Thus, an alternative acetate source is required.
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Affiliation(s)
- Patrick M Long
- From the Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont 05405
| | - John R Moffett
- the Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, and
| | - Aryan M A Namboodiri
- the Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, and
| | - Mariano S Viapiano
- the Department of Neurosurgery, Brigham and Women's Hospital, Boston, Massachusetts 02215
| | - Sean E Lawler
- the Department of Neurosurgery, Brigham and Women's Hospital, Boston, Massachusetts 02215
| | - Diane M Jaworski
- From the Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont 05405,.
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33
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Ahmed SS, Li H, Cao C, Sikoglu EM, Denninger AR, Su Q, Eaton S, Liso Navarro AA, Xie J, Szucs S, Zhang H, Moore C, Kirschner DA, Seyfried TN, Flotte TR, Matalon R, Gao G. A single intravenous rAAV injection as late as P20 achieves efficacious and sustained CNS Gene therapy in Canavan mice. Mol Ther 2013; 21:2136-47. [PMID: 23817205 DOI: 10.1038/mt.2013.138] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Accepted: 05/29/2013] [Indexed: 11/09/2022] Open
Abstract
Canavan's disease (CD) is a fatal pediatric leukodystrophy caused by mutations in aspartoacylase (AspA) gene. Currently, there is no effective treatment for CD; however, gene therapy is an attractive approach to ameliorate the disease. Here, we studied progressive neuropathology and gene therapy in short-lived (≤ 1 month) AspA(-/-) mice, a bona-fide animal model for the severest form of CD. Single intravenous (IV) injections of several primate-derived recombinant adeno-associated viruses (rAAVs) as late as postnatal day 20 (P20) completely rescued their early lethality and alleviated the major disease symptoms, extending survival in P0-injected rAAV9 and rAAVrh8 groups to as long as 2 years thus far. We successfully used microRNA (miRNA)-mediated post-transcriptional detargeting for the first time to restrict therapeutic rAAV expression in the central nervous system (CNS) and minimize potentially deleterious effects of transgene overexpression in peripheral tissues. rAAV treatment globally improved CNS myelination, although some abnormalities persisted in the content and distribution of myelin-specific and -enriched lipids. We demonstrate that systemically delivered and CNS-restricted rAAVs can serve as efficacious and sustained gene therapeutics in a model of a severe neurodegenerative disorder even when administered as late as P20.
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Affiliation(s)
- Seemin Seher Ahmed
- 1] Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA [2] Department of Microbiology & Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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34
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Abstract
The inherited leukodystrophy Canavan disease arises due to a loss of the ability to catabolize N-acetylaspartic acid (NAA) in the brain and constitutes a major point of focus for efforts to define NAA function. Accumulation of noncatabolized NAA is diagnostic for Canavan disease, but contrasts with the abnormally low NAA associated with compromised neuronal integrity in a broad spectrum of other clinical conditions. Experimental evidence for NAA function supports a role in white matter lipid synthesis, but does not explain how both elevated and lowered NAA can be associated with pathology in the brain. We have undertaken a systematic analysis of postnatal development in a mouse model of Canavan disease that delineates development and pathology by identifying markers of oxidative stress preceding oligodendrocyte loss and dysmyelination. These data suggest a role for NAA in the maintenance of metabolic integrity in oligodendrocytes that may be of relevance to the strong association between NAA and neuronal viability. N-acetylaspartic acid is proposed here to support lipid synthesis and energy metabolism via the provision of substrate for both cellular processes during early postnatal development.
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Lewis SJ, Shine JM, Duffy S, Halliday G, Naismith SL. Anterior cingulate integrity: Executive and neuropsychiatric features in Parkinson's disease. Mov Disord 2012; 27:1262-7. [DOI: 10.1002/mds.25104] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 05/28/2012] [Accepted: 06/11/2012] [Indexed: 11/06/2022] Open
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Moffett JR, Arun P, Ariyannur PS, Garbern JY, Jacobowitz DM, Namboodiri AMA. Extensive aspartoacylase expression in the rat central nervous system. Glia 2011; 59:1414-34. [PMID: 21598311 PMCID: PMC3143213 DOI: 10.1002/glia.21186] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 04/14/2011] [Indexed: 11/08/2022]
Abstract
Aspartoacylase (ASPA) catalyzes deacetylation of N-acetylaspartate (NAA) to generate acetate and aspartate. Mutations in the gene for ASPA lead to reduced acetate availability in the CNS during development resulting in the fatal leukodystrophy Canavan disease. Highly specific polyclonal antibodies to ASPA were used to examine CNS expression in adult rats. In white matter, ASPA expression was associated with oligodendrocyte cell bodies, nuclei, and some processes, but showed a dissimilar distribution pattern to myelin basic protein and oligodendrocyte specific protein. Microglia expressed ASPA in all CNS regions examined, as did epiplexus cells of the choroid plexus. Pial and ependymal cells and some endothelial cells were ASPA positive, as were unidentified cellular nuclei throughout the CNS. Astrocytes did not express ASPA in their cytoplasm. In some fiber pathways and nerves, particularly in the brainstem and spinal cord, the axoplasm of many neuronal fibers expressed ASPA, as did some neurons. Acetyl coenzyme A synthase immunoreactivity was also observed in the axoplasm of many of the same fiber pathways and nerves. All ASPA-immunoreactive elements were unstained in brain sections from tremor rats, an ASPA-null mutant. The strong expression of ASPA in oligodendrocyte cell bodies is consistent with a lipogenic role in myelination. Strong ASPA expression in cell nuclei is consistent with a role for NAA-derived acetate in nuclear acetylation reactions, including histone acetylation. Expression of ASPA in microglia may indicate a role in lipid synthesis in these cells, whereas expression in axons suggests that some neurons can both synthesize and catabolize NAA.
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Affiliation(s)
- John R Moffett
- Department of Anatomy, Physiology & Genetics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA.
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Karaman S, Barnett J, Sykes GP, Hong B, Delaney B. Two-generation reproductive and developmental toxicity assessment of dietary N-acetyl-L-aspartic acid in rats. Food Chem Toxicol 2011; 49:3192-205. [PMID: 21920405 DOI: 10.1016/j.fct.2011.08.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 08/26/2011] [Accepted: 08/27/2011] [Indexed: 10/17/2022]
Abstract
N-acetyl-l-aspartic acid (NAA) is a component of the mammalian central nervous system (CNS) that has also been identified in a number of foods. This paper reports the outcome of a reproductive toxicology study conducted with NAA in Sprague-Dawley rats. NAA was added to diets at target doses of 100, 250 and 500 mg/kg of body weight/day and administered for two consecutive generations. A carrier control group was administered diet with no added NAA and a comparative control group was given aspartate (ASP), the constituent amino acid of NAA, at a target dose of 500 mg/kg of body weight/day. The study evaluated OECD 416 reproductive performance variables and additional segments to assess potential developmental effects, neurobehavioural and ophthalmologic function, and the concentrations of NAA or ASP in brain and plasma. No biologically significant differences were observed in any reproductive response variables, neurobehavioural tests, ophthalmologic examinations, body weights, feed consumption, or organ weights. Further, no test substance related mortalities or adverse clinical, neurohistopathologic or histopathologic findings were observed. Under the conditions of this study, the highest target dose of NAA, 500 mg/kg of body weight/day, represents the no-observed-adverse-effect-level (NOAEL) for reproductive and systemic toxicity, and neurotoxicity for Sprague-Dawley rats.
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Affiliation(s)
- Sule Karaman
- Pioneer Hi-Bred, International, Inc., Ankeny, IA 50021-7102, USA
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Jennen D, Ruiz-Aracama A, Magkoufopoulou C, Peijnenburg A, Lommen A, van Delft J, Kleinjans J. Integrating transcriptomics and metabonomics to unravel modes-of-action of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in HepG2 cells. BMC SYSTEMS BIOLOGY 2011; 5:139. [PMID: 21880148 PMCID: PMC3231768 DOI: 10.1186/1752-0509-5-139] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 08/31/2011] [Indexed: 12/30/2022]
Abstract
BACKGROUND The integration of different 'omics' technologies has already been shown in several in vivo studies to offer a complementary insight into cellular responses to toxic challenges. Being interested in developing in vitro cellular models as alternative to animal-based toxicity assays, we hypothesize that combining transcriptomics and metabonomics data improves the understanding of molecular mechanisms underlying the effects caused by a toxic compound also in vitro in human cells. To test this hypothesis, and with the focus on non-genotoxic carcinogenesis as an endpoint of toxicity, in the present study, the human hepatocarcinoma cell line HepG2 was exposed to the well-known environmental carcinogen 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). RESULTS Transcriptomics as well as metabonomics analyses demonstrated changes in TCDD-exposed HepG2 in common metabolic processes, e.g. amino acid metabolism, of which some of the changes only being confirmed if both 'omics' were integrated. In particular, this integrated analysis identified unique pathway maps involved in receptor-mediated mechanisms, such as the G-protein coupled receptor protein (GPCR) signaling pathway maps, in which the significantly up-regulated gene son of sevenless 1 (SOS1) seems to play an important role. SOS1 is an activator of several members of the RAS superfamily, a group of small GTPases known for their role in carcinogenesis. CONCLUSIONS The results presented here were not only comparable with other in vitro studies but also with in vivo studies. Moreover, new insights on the molecular responses caused by TCDD exposure were gained by the cross-omics analysis.
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Affiliation(s)
- Danyel Jennen
- Department of Toxicogenomics, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
- Netherlands Toxicogenomics Centre, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Ainhoa Ruiz-Aracama
- RIKILT-Institute of Food Safety, Wageningen University and Research Centre, PO Box 230, 6700 AE Wageningen, the Netherlands
- Netherlands Toxicogenomics Centre, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Christina Magkoufopoulou
- Department of Toxicogenomics, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Ad Peijnenburg
- RIKILT-Institute of Food Safety, Wageningen University and Research Centre, PO Box 230, 6700 AE Wageningen, the Netherlands
- Netherlands Toxicogenomics Centre, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Arjen Lommen
- RIKILT-Institute of Food Safety, Wageningen University and Research Centre, PO Box 230, 6700 AE Wageningen, the Netherlands
- Netherlands Toxicogenomics Centre, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Joost van Delft
- Department of Toxicogenomics, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
- Netherlands Toxicogenomics Centre, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Jos Kleinjans
- Department of Toxicogenomics, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
- Netherlands Toxicogenomics Centre, PO Box 616, 6200 MD Maastricht, the Netherlands
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Segel R, Anikster Y, Zevin S, Steinberg A, Gahl WA, Fisher D, Staretz-Chacham O, Zimran A, Altarescu G. A safety trial of high dose glyceryl triacetate for Canavan disease. Mol Genet Metab 2011; 103:203-6. [PMID: 21474353 DOI: 10.1016/j.ymgme.2011.03.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 03/09/2011] [Accepted: 03/09/2011] [Indexed: 10/18/2022]
Abstract
Canavan disease (CD MIM#271900) is a rare autosomal recessive neurodegenerative disorder presenting in early infancy. The course of the disease is variable, but it is always fatal. CD is caused by mutations in the ASPA gene, which codes for the enzyme aspartoacylase (ASPA), which breaks down N-acetylaspartate (NAA) to acetate and aspartic acid. The lack of NAA-degrading enzyme activity leads to excess accumulation of NAA in the brain and deficiency of acetate, which is necessary for myelin lipid synthesis. Glyceryltriacetate (GTA) is a short-chain triglyceride with three acetate moieties on a glycerol backbone and has proven an effective acetate precursor. Intragastric administration of GTA to tremor mice results in greatly increased brain acetate levels, and improved motor functions. GTA given to infants with CD at a low dose (up to 0.25 g/kg/d) resulted in no improvement in their clinical status, but also no detectable toxicity. We present for the first time the safety profile of high dose GTA (4.5 g/kg/d) in 2 patients with CD. We treated 2 infants with CD at ages 8 months and 1 year with high dose GTA, for 4.5 and 6 months respectively. No significant side effects and no toxicity were observed. Although the treatment resulted in no motor improvement, it was well tolerated. The lack of clinical improvement might be explained mainly by the late onset of treatment, when significant brain damage was already present. Further larger studies of CD patients below age 3 months are required in order to test the long-term efficacy of this drug.
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Affiliation(s)
- Reeval Segel
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel.
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Napolioni V, Persico AM, Porcelli V, Palmieri L. The mitochondrial aspartate/glutamate carrier AGC1 and calcium homeostasis: physiological links and abnormalities in autism. Mol Neurobiol 2011; 44:83-92. [PMID: 21691713 DOI: 10.1007/s12035-011-8192-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 06/02/2011] [Indexed: 10/18/2022]
Abstract
Autism spectrum disorder (ASD) is a severe, complex neurodevelopmental disorder characterized by impairments in reciprocal social interaction and communication, and restricted and stereotyped patterns of interests and behaviors. Recent evidence has unveiled an important role for calcium (Ca(2+)) signaling in the pathogenesis of ASD. Post-mortem studies of autistic brains have pointed toward abnormalities in mitochondrial function as possible downstream consequences of altered Ca(2+) signaling, abnormal synapse formation, and dysreactive immunity. SLC25A12, an ASD susceptibility gene, encodes the Ca(2+)-regulated mitochondrial aspartate-glutamate carrier, isoform 1 (AGC1). AGC1 is an important component of the malate/aspartate shuttle, a crucial system supporting oxidative phosphorylation and adenosine triphosphate (ATP) production. Here, we review the physiological roles of AGC1, its links to calcium homeostasis, and its involvement in autism pathogenesis.
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Affiliation(s)
- Valerio Napolioni
- Laboratory of Molecular Psychiatry & Neurogenetics, University Campus Bio-Medico, Via Alvaro del Portillo 21, 00128 Rome, Italy
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Ramos M, Pardo B, Llorente-Folch I, Saheki T, del Arco A, Satrústegui J. Deficiency of the mitochondrial transporter of aspartate/glutamate aralar/AGC1 causes hypomyelination and neuronal defects unrelated to myelin deficits in mouse brain. J Neurosci Res 2011; 89:2008-17. [DOI: 10.1002/jnr.22639] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 01/31/2011] [Accepted: 02/08/2011] [Indexed: 12/24/2022]
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Zano S, Malik R, Szucs S, Matalon R, Viola RE. Modification of aspartoacylase for potential use in enzyme replacement therapy for the treatment of Canavan disease. Mol Genet Metab 2011; 102:176-80. [PMID: 21095151 PMCID: PMC3022971 DOI: 10.1016/j.ymgme.2010.10.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2010] [Accepted: 10/25/2010] [Indexed: 11/17/2022]
Abstract
Canavan disease is a fatal neurological disease without any effective treatments to slow the relentless progress of this disorder. Enzyme replacement therapy has been used effectively to treat a number of metabolic disorders, but the presence of the blood-brain-barrier presents an additional challenge in the treatment of neurological disorders. Studies have begun with the aim of establishing a treatment protocol that can effectively replace the defective enzyme in Canavan disease patients. The human enzyme, aspartoacylase, has been cloned, expressed and purified, and the surface lysyl groups modified through PEGylation. Fully active modified enzymes were administered to mice that are defective in this enzyme and that show many of the symptoms of Canavan disease. Statistically significant increases in brain enzyme activity levels have been achieved in this animal model, as well as decreases in the elevated substrate levels that mimic those found in Canavan disease patients. These results demonstrate that the modified enzyme is gaining access to the brain and functions to correct this metabolic defect. The stage is now set for a long term study to optimize this enzyme replacement approach for the development of a treatment protocol.
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Affiliation(s)
- Stephen Zano
- Department of Chemistry, University of Toledo, Toledo, OH 43606, USA
| | - Radhika Malik
- Department of Chemistry, University of Toledo, Toledo, OH 43606, USA
| | - Sylvia Szucs
- Department of Pediatrics, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Reuben Matalon
- Department of Pediatrics, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Ronald E. Viola
- Department of Chemistry, University of Toledo, Toledo, OH 43606, USA
- Corresponding author at: Department of Chemistry, University of Toledo, 2801 W. Bancroft Street, Toledo, Ohio 43606, USA, Phone: 419-530-1582, Fax:419 -530-1583,
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Karaman S, Barnett J, Sykes GP, Delaney B. Subchronic oral toxicity assessment of N-acetyl-L-aspartic acid in rats. Food Chem Toxicol 2010; 49:155-65. [PMID: 20946933 DOI: 10.1016/j.fct.2010.10.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 10/04/2010] [Accepted: 10/07/2010] [Indexed: 11/25/2022]
Abstract
We investigated the systemic effects of subchronic dietary exposure to NAA in Sprague Dawley® rats. NAA was added to the diet at different concentrations to deliver target doses of 100, 250 and 500 mg/kg of body weight/day and was administered for 90 consecutive days. All rats (10/sex/group) survived until scheduled sacrifice. No diet-related differences in body weights, feed consumption and efficiency, clinical signs, or ophthalmologic findings were observed. No biologically significant differences or adverse effects were observed in functional observation battery (FOB) and motor activity evaluations, hematology, coagulation, clinical chemistry, urinalysis, organ weights, or gross pathology evaluations that were attributable to dietary exposure to NAA. Treatment-related increased incidence and degree of acinar cell hypertrophy in salivary glands was observed in both male and female rats in the high dose group. Because there was no evidence of injury or cytotoxicity to the salivary glands, this finding was not considered to be an adverse effect. Based on these results and the actual average doses consumed, the no-observed-adverse-effect-levels (NOAEL) for systemic toxicity from subchronic dietary exposure to NAA were 451.6 and 490.8 mg/kg of body weight/day for male and female Sprague Dawley® rats, respectively.
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Affiliation(s)
- Sule Karaman
- Pioneer Hi-Bred International, Inc., Ankeny, Iowa 50021-7102, USA
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Vagnozzi R, Signoretti S, Cristofori L, Alessandrini F, Floris R, Isgro E, Ria A, Marziale S, Zoccatelli G, Tavazzi B, Del Bolgia F, Sorge R, Broglio SP, McIntosh TK, Lazzarino G. Assessment of metabolic brain damage and recovery following mild traumatic brain injury: a multicentre, proton magnetic resonance spectroscopic study in concussed patients. Brain 2010; 133:3232-42. [DOI: 10.1093/brain/awq200] [Citation(s) in RCA: 295] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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46
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Biochemical disorders induced by cytotoxic marine natural products in breast cancer cells as revealed by proton NMR spectroscopy-based metabolomics. Biochem Pharmacol 2010; 80:1170-9. [PMID: 20637732 DOI: 10.1016/j.bcp.2010.07.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 07/05/2010] [Accepted: 07/07/2010] [Indexed: 12/16/2022]
Abstract
Marine plants and animals are sources of a huge number of pharmacologically active compounds, some of which exhibit antineoplastic activity of clinical relevance. However the mechanism of action of marine natural products (MNPs) is poorly understood. In this study, proton NMR spectroscopy-based metabolomics was applied to unravel biochemical disorders induced in human MCF7 breast cancer cells by 3 lead candidate anticancer MNPs: ascididemin (Asc), lamellarin-D (Lam-D), and kahalalide F (KF). Asc, Lam-D, and KF provoked a severe decrease in DNA content in MCF7 cells after 24-h treatment. Asc and Lam-D provoked apoptosis, whereas KF induced non-apoptotic cell death. Metabolite profiling revealed major biochemical disorders following treatment. The response of MCF7 tumor cells to Asc involved the accumulation of citrate (x17 the control level, P<0.001), testifying enzyme blockade in citrate metabolism, and the accumulation of gluconate (x9.8, P<0.005), a metabolite never reported at such concentration in tumor cells, probably testifying glycolysis shutdown. The response to Lam-D involved the accumulation of aspartate (x7.2, P<0.05), glutamate (x14.7, P<0.05), and lactate (x2.3, P<0.05), probably in relation with the targeting of the malate-aspartate shuttle, as discussed. The response to KF involved increased lipid accumulation (polyunsaturated fatty acids x9.8, P<0.05), and phospholipid and acetate derivative alterations. Altogether, this study demonstrates the potential of proton NMR spectroscopy-based metabolomics to help uncover metabolic targets and elucidate the mechanism of cytotoxicity of candidate antineoplastic MNPs.
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Mattan NS, Ghiani CA, Lloyd M, Matalon R, Bok D, Casaccia P, de Vellis J. Aspartoacylase deficiency affects early postnatal development of oligodendrocytes and myelination. Neurobiol Dis 2010; 40:432-43. [PMID: 20637282 DOI: 10.1016/j.nbd.2010.07.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 06/29/2010] [Accepted: 07/07/2010] [Indexed: 12/21/2022] Open
Abstract
Canavan disease (CD) is a neurodegenerative disease, caused by a deficiency in the enzyme aspartoacylase (ASPA). This enzyme has been localized to oligodendrocytes; however, it is still undefined how ASPA deficiency affects oligodendrocyte development. In normal mice the pattern of ASPA expression coincides with oligodendrocyte maturation. Therefore, postnatal oligodendrocyte maturation was analyzed in ASPA-deficient mice (CD mice). Early in development, CD mice brains showed decreased expression of neural cell markers that was later compensated. In addition, the levels of myelin proteins were decreased along with abnormal myelination in CD mice compared to wild-type (WT). These defects were associated with increased global levels of acetylated histone H3, decreased chromatin compaction and increased GFAP protein, a marker for astrogliosis. Together, these findings strongly suggest that, early in postnatal development, ASPA deficiency affects oligodendrocyte maturation and myelination.
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Affiliation(s)
- Natalia S Mattan
- Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
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48
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Ariyannur PS, Moffett JR, Manickam P, Pattabiraman N, Arun P, Nitta A, Nabeshima T, Madhavarao CN, Namboodiri AMA. Methamphetamine-induced neuronal protein NAT8L is the NAA biosynthetic enzyme: implications for specialized acetyl coenzyme A metabolism in the CNS. Brain Res 2010; 1335:1-13. [PMID: 20385109 DOI: 10.1016/j.brainres.2010.04.008] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 02/20/2010] [Accepted: 04/05/2010] [Indexed: 01/12/2023]
Abstract
N-acetylaspartate (NAA) is a concentrated, neuron-specific brain metabolite routinely used as a magnetic resonance spectroscopy marker for brain injury and disease. Despite decades of research, the functional roles of NAA remain unclear. Biochemical investigations over several decades have associated NAA with myelin lipid synthesis and energy metabolism. However, studies have been hampered by an inability to identify the gene for the NAA biosynthetic enzyme aspartate N-acetyltransferase (Asp-NAT). A very recent report has identified Nat8l as the gene encoding Asp-NAT and confirmed that the only child diagnosed with a lack of NAA on brain magnetic resonance spectrograms has a 19-bp deletion in this gene. Based on in vitro Nat8l expression studies the researchers concluded that many previous biochemical investigations have been technically flawed and that NAA may not be associated with brain energy or lipid metabolism. In studies done concurrently in our laboratory we have demonstrated via cloning, expression, specificity for acetylation of aspartate, responsiveness to methamphetamine treatment, molecular modeling and comparative immunolocalization that NAT8L is the NAA biosynthetic enzyme Asp-NAT. We conclude that NAA is a major storage and transport form of acetyl coenzyme A specific to the nervous system, thus linking it to both lipid synthesis and energy metabolism.
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Affiliation(s)
- Prasanth S Ariyannur
- Uniformed Services University of Health Sciences, Department of Anatomy, Physiology and Genetics, Molecular and Cell Biology Program, Neuroscience Program, 4301 Jones Bridge Road, Bldg C, Rm 2069, APG, Bethesda, MD 20814, USA
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Madhavarao CN, Arun P, Anikster Y, Mog SR, Staretz-Chacham O, Moffett JR, Grunberg NE, Gahl WA, Namboodiri AMA. Glyceryl triacetate for Canavan disease: a low-dose trial in infants and evaluation of a higher dose for toxicity in the tremor rat model. J Inherit Metab Dis 2009; 32:640. [PMID: 19685155 DOI: 10.1007/s10545-009-1155-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 06/24/2009] [Accepted: 06/25/2009] [Indexed: 12/24/2022]
Abstract
Canavan disease (CD) is a fatal dysmyelinating genetic disorder associated with aspartoacylase deficiency, resulting in decreased brain acetate levels and reduced myelin lipid synthesis in the developing brain. Here we tested tolerability of a potent acetate precursor, glyceryl triacetate (GTA), at low doses in two infants diagnosed with CD, aged 8 and 13 months. Much higher doses of GTA were evaluated for toxicity in the tremor rat model of CD. GTA was given orally to the infants for up to 4.5 and 6 months, starting at 25 mg/kg twice daily, doubling the dose weekly until a maximum of 250 mg/kg reached. Wild-type and tremor rat pups were given GTA orally twice daily, initially at a dose of 4.2 g/kg from postnatal days 7 through 14, and at 5.8 g/kg from day 15 through 23, and thereafter in food (7.5%) and water (5%). At the end of the trial (approximately 90 to 120 days) sera and tissues from rats were analysed for changes in blood chemistry and histopathology. GTA treatment caused no detectable toxicity and the patients showed no deterioration in clinical status. In the high-dose animal studies, no significant differences in the mean blood chemistry values occurred between treated and untreated groups, and no lesions indicating toxicity were detectable in any of the tissues examined. Lack of GTA toxicity in two CD patients in low-dose trials, as well as in high-dose animal studies, suggests that higher, effective dose studies in human CD patients are warranted.
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Affiliation(s)
- C N Madhavarao
- Department of Anatomy, Physiology and Genetics, Program in Neuroscience and Program in Molecular and Cell Biology, USUHS, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - P Arun
- Department of Anatomy, Physiology and Genetics, Program in Neuroscience and Program in Molecular and Cell Biology, USUHS, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Y Anikster
- Metabolic Disease Unit, Safra Children Hospital, Sheba Medical Center, Tel-Hashomer, and Sackler Medical School, Tel Aviv University, Tel Aviv, Israel
| | - S R Mog
- Division of Comparative Pathology, AFRRI, Bethesda, MD, USA
| | | | - J R Moffett
- Department of Anatomy, Physiology and Genetics, Program in Neuroscience and Program in Molecular and Cell Biology, USUHS, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - N E Grunberg
- Department of Medical and Clinical Psychology, Program in Neuroscience, USUHS, Bethesda, MD, USA
| | - W A Gahl
- Medical Genetics Branch, NHGRI, NIH, Bethesda, MD, USA
| | - A M A Namboodiri
- Department of Anatomy, Physiology and Genetics, Program in Neuroscience and Program in Molecular and Cell Biology, USUHS, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA.
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50
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Wang J, Leone P, Wu G, Francis JS, Li H, Jain MR, Serikawa T, Ledeen RW. Myelin lipid abnormalities in the aspartoacylase-deficient tremor rat. Neurochem Res 2008; 34:138-48. [PMID: 18478328 DOI: 10.1007/s11064-008-9726-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Accepted: 04/21/2008] [Indexed: 11/25/2022]
Abstract
The high concentration of N-acetylaspartate (NAA) in neurons of the central nervous system and its growing clinical use as an indicator of neuronal viability has intensified interest in the biological function of this amino acid derivative. The biomedical relevance of such inquiries is highlighted by the myelin-associated pathology of Canavan disease, an inherited childhood disorder resulting from mutation of aspartoacylase (ASPA), the NAA-hydrolyzing enzyme. This enzyme is known to be localized in oligodendrocytes with bimodal distribution in cytosol and the myelin sheath, and to produce acetyl groups utilized in myelin lipid synthesis. Loss of this acetyl source in Canavan disease and rodent models such as the tremor rat are thought to account for the observed myelin deficit. This study was undertaken to further define and quantify the specific lipid abnormalities that occur as a result of ASPA deficit in the tremor rat. Employing mass spectrometry together with high performance thin-layer chromatography, we found that myelin from 28-day-old animals showed major reduction in cerebrosides (CB) and sulfatides (Sulf) with unsubstituted fatty acids, and equal if not greater changes in myelin from 7-month-old tremors. Cerebrosides with 2-hydroxyfatty acids showed little if any change at either age; Sulf with 2-hydroxyfatty acids showed no significant change at 28 days, but surprisingly a major increase at 7 months. Two species of phosphatidylcholine, 32:0 and 34:1, also showed significant increase, but only at 28 days. One form of phosphatidylethanolamine, PE36:1, was reduced a modest amount at both ages, whereas the plasmalogen form did not change. The dysmyelination that results from inactivation of ASPA is thus characterized by selective decreases as well as some increases in specific lipids.
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Affiliation(s)
- Jianfeng Wang
- Department of Neurology and Neurosciences, New Jersey Medical School, UMDNJ, 185 So. Orange Ave., MSB-H506, Newark, NJ 07103, USA
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