1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Xiong F, Jiang K, Wu Y, Lou C, Ding C, Zhang W, Zhang X, Li C, Zheng H, Gao H. Intermittent fasting alleviates type 1 diabetes-induced cognitive dysfunction by improving the frontal cortical metabolic disorder. Biochim Biophys Acta Mol Basis Dis 2023:166725. [PMID: 37127173 DOI: 10.1016/j.bbadis.2023.166725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 04/06/2023] [Accepted: 04/17/2023] [Indexed: 05/03/2023]
Abstract
Intermittent fasting (IF) is an ecological strategy to control various metabolic disorder symptoms, but its protective effect on type 1 diabetes (T1D)-induced cognitive dysfunction and the underlying mechanisms remain poorly defined. Herein, we examined the efficacy of IF in altering the behaviors and brain metabolome in T1D mice and investigated the potential molecular mechanisms. We demonstrated that IF remarkably improved frontal cortical-dependent memory in T1D mice and reduced the loss of neuronal cells. Metabolomics and targeted mass spectrometry assay showed that IF reprogrammed the frontal cortical metabolome composition, including activated the aspartate and glutamate pathway and reversed glycerophospholipid and sphingolipid depositions in T1D mice. Mechanistically, IF attenuated the levels of oxidative stress proteins, such as NOX2, NOX4, 8-OHdG, 4-HNE, and inhibited the levels of pro-apoptotic factors Bax and cleaved Caspase-3, finally improved the memory ability of T1D mice. In vitro studies confirmed the protective effect of the supplemented N-acetylaspartate, a pivotal metabolite involved in IF-regulated T1D-induced cognitive dysfunction, in high glucose-stimulated SH-SY5Y cells by eliminating toxic lipids accumulation, oxidative stress and apoptosis. To conclude, the frontal cortical metabolites mediated the protective effects of IF against T1D-induced cognitive dysfunction by attenuating oxidative stress and apoptotic signaling. Thus, IF can be a potential therapeutic strategy for T1D-induced cognitive dysfunction.
Collapse
Affiliation(s)
- Fen Xiong
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Institute of Metabonomics & Medical NMR, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Kaiyuan Jiang
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Institute of Metabonomics & Medical NMR, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Yali Wu
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Institute of Metabonomics & Medical NMR, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Cong Lou
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Institute of Metabonomics & Medical NMR, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Chengjie Ding
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Institute of Metabonomics & Medical NMR, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Wenli Zhang
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Institute of Metabonomics & Medical NMR, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Xi Zhang
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Institute of Metabonomics & Medical NMR, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China
| | - Chen Li
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Institute of Metabonomics & Medical NMR, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China.
| | - Hong Zheng
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Institute of Metabonomics & Medical NMR, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China.
| | - Hongchang Gao
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Institute of Metabonomics & Medical NMR, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China; Key Laboratory of Efficacy Evaluation of Traditional Chinese Medicine and Encephalopathy Research of Zhejiang Province, Wenzhou 325035, China.
| |
Collapse
|
3
|
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]
|
4
|
Olszewska A, Schmidt MJ, Failing K, Nicpoń J, Podgórski P, Wrzosek MA. Interictal Single-Voxel Proton Magnetic Resonance Spectroscopy of the Temporal Lobe in Dogs With Idiopathic Epilepsy. Front Vet Sci 2020; 7:644. [PMID: 33195502 PMCID: PMC7541947 DOI: 10.3389/fvets.2020.00644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 08/10/2020] [Indexed: 11/16/2022] Open
Abstract
Proton magnetic resonance spectroscopy (H1-MRS) could provide insight into the metabolic pathophysiology of the temporal lobe of canine brain after seizure. Currently, there is no evidence-based data available on MRS of temporal lobe in dogs with idiopathic epilepsy (IE). The aim of this prospective, cross-sectional study was to evaluate the interictal metabolic activity of the temporal lobe in IE dogs compared to a control group with the use of H1-MRS. Ten healthy dogs and 27 client-owned dogs with IE underwent 1.5-Tesla magnetic resonance imaging (MRI) and single-voxel H1-MRS. The MRS studies were acquired as spin echoes with a repetition time (TR) of 2,000 ms and an echo time (TE) of 144 ms. A cubic voxel (10 ×10 ×10 mm) was positioned bilaterally into the region of the left and right temporal lobe, including a middle part of the hippocampus and the amygdala. The N-acetylaspartate (NAA)-to-creatine (NAA/Cr), NAA-to-choline (NAA/Cho), choline-to-creatine (Cho/Cr), and choline-to-NAA (Cho/NAA) ratios were determined in both hemispheres and compared to controls. No significant differences in all metabolite ratios between epileptic dogs and the control group could be found. A time-dependent decrease in the NAA/Cho ratio as well as an increase in the Cho/NAA ratio was found with proximity in time to the last seizure. We found no correlation between metabolite ratios and age or sex in this animal group. Time span from the last seizure to the acquisition of MRS significantly correlated with NAA/Cho and Cho/NAA ratio. We conclude that without a time relation, metabolite ratios in dogs with IE do not differ from those of the control group.
Collapse
Affiliation(s)
- Agnieszka Olszewska
- Department of Veterinary Clinical Science, Small Animal Clinic, Justus-Liebig-University Giessen, Giessen, Germany
| | - Martin Jürgen Schmidt
- Department of Veterinary Clinical Science, Small Animal Clinic, Justus-Liebig-University Giessen, Giessen, Germany
| | - Klaus Failing
- Unit for Biomathematics and Data Processing, Faculty of Veterinary Medicine, Justus Liebig-University Giessen, Giessen, Germany
| | - Józef Nicpoń
- Department of Internal Diseases With a Clinic for Horses, Dogs and Cats, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland.,Center of Experimental Diagnostics and Innovative Biomedical Technologies, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
| | - Przemysław Podgórski
- Department of General Radiology and Interventional Radiology and Neuroradiology, Wrocław Medical University, Wrocław, Poland
| | - Marcin Adam Wrzosek
- Department of Internal Diseases With a Clinic for Horses, Dogs and Cats, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Wrocław, Poland
| |
Collapse
|
5
|
Nishitani A, Nagayoshi H, Takenaka S, Asano M, Shimizu S, Ohno Y, Kuramoto T. Involvement of NMDA receptors in tremor expression in Aspa/Hcn1 double-knockout rats. Exp Anim 2020; 69:388-394. [PMID: 32507787 PMCID: PMC7677080 DOI: 10.1538/expanim.20-0025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We recently demonstrated that aspartoacylase (Aspa) and
hyperpolarization-activated cyclic nucleotide-gated potassium channel 1
(Hcn1) genes were causative of essential tremor (ET) in rats. This
finding was obtained using
Aspaem34Kyo/Hcn1A354V
double-mutant rats, but they were bred on a heterogeneous genetic background of two
strains, F344 and WTC. Here, we developed an
Aspaem34Kyo/Hcn1em1Kyo
double-knockout rat strain with a homogenous F344 genetic background and studied the
ability of glutamate receptor antagonists to suppress ET. The
F344-Aspa/Hcn1 double-knockout rats exhibited
spontaneous, intense body tremor equivalent to that in the double-mutant rats.
N-acetyl-aspartate (NAA), a substrate of ASPA, showed accumulation in
all brain regions and in the spinal cord. However,
N-acetyl-aspartyl-glutamate (NAAG), which is derived from NAA and
interacts with glutamatergic receptors, was decreased in the medulla oblongata of the
double-knockout rats. The tremor was suppressed by
3-[(R)-2-carboxypiperazin-4-yl]-prop-2-enyl-1-phosphonic acid, an
N-methyl-D-aspartate (NMDA) receptor antagonist, in
F344-Aspa/Hcn1 double-knockout rats. The non-NMDA
glutamate receptor antagonist NBQX weakly inhibited the tremor, while the metabotropic
glutamate receptor antagonist LY341495 showed no effect. In addition, both NR2B
subunit-specific (Ro 25-6981) and NR2C/NR2D subunit-specific (cis-piperidine dicarboxylic
acid) NMDA receptor antagonists suppressed the tremor. These data indicated that the
pathogenesis of tremor in Aspa/Hcn1 double-knockout rats
involved ionotropic glutamate receptors, particularly NMDA receptors.
Collapse
Affiliation(s)
- Ai Nishitani
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Haruna Nagayoshi
- Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka 537-0025, Japan
| | - Shigeo Takenaka
- Department of Clinical Nutrition, Graduate School of Comprehensive Rehabilitation, Osaka Prefecture University, 3-7-30 Habikino, Osaka 583-8555, Japan
| | - Masahide Asano
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Saki Shimizu
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| | - Yukihiro Ohno
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
| | - Takashi Kuramoto
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.,Department of Animal Science, Faculty of Agriculture, Tokyo University of Agriculture, 1737 Funako, Atsugi, Kanagawa 243-0034, Japan
| |
Collapse
|
6
|
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.
Collapse
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
| |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
Abstract
Metabolic disorders comprise a large group of heterogeneous diseases ranging from very prevalent diseases such as diabetes mellitus to rare genetic disorders like Canavan Disease. Whether either of these diseases is amendable by gene therapy depends to a large degree on the knowledge of their pathomechanism, availability of the therapeutic gene, vector selection, and availability of suitable animal models. In this book chapter, we review three metabolic disorders of the central nervous system (CNS; Canavan Disease, Niemann-Pick disease and Phenylketonuria) to give examples for primary and secondary metabolic disorders of the brain and the attempts that have been made to use adeno-associated virus (AAV) based gene therapy for treatment. Finally, we highlight commonalities and obstacles in the development of gene therapy for metabolic disorders of the CNS exemplified by those three diseases.
Collapse
Affiliation(s)
- Dominic J Gessler
- University of Massachusetts Medical School, 368 Plantation Street, AS6-2049, Worcester, MA, 01605, USA
| | - Guangping Gao
- University of Massachusetts Medical School, 368 Plantation Street, AS6-2049, Worcester, MA, 01605, USA.
| |
Collapse
|
9
|
Ahmed SS, Gao G. Making the White Matter Matters: Progress in Understanding Canavan's Disease and Therapeutic Interventions Through Eight Decades. JIMD Rep 2015; 19:11-22. [PMID: 25604619 DOI: 10.1007/8904_2014_356] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 08/05/2014] [Accepted: 08/12/2014] [Indexed: 12/24/2022] Open
Abstract
Canavan's disease (CD) is a fatal autosomal recessive pediatric leukodystrophy in which patients show severe neurodegeneration and typically die by the age of 10, though life expectancy in patients can be highly variable. Currently, there is no effective treatment for CD; however, gene therapy seems to be a feasible approach to combat the disease. Being a monogenic defect, the disease provides an excellent model system to develop gene therapy approaches that can be extended to other monogenic leukodystrophies and neurodegenerative diseases. CD results from mutations in a single gene aspartoacylase which hydrolyses N-acetyl aspartic acid (NAA) which accumulates in its absences. Since CD is one of the few diseases that show high NAA levels, it can also be used to study the enigmatic biological role of NAA. The disease was first described in 1931, and this review traces the progress made in the past 8 decades to understand the disease by enumerating current hypotheses and ongoing palliative measures to alleviate patient symptoms in the context of the latest advances in the field.
Collapse
Affiliation(s)
- Seemin S Ahmed
- University of Massachusetts Medical School, 368 Plantation Street, ASC6, Worcester, MA, 01605, USA
| | | |
Collapse
|
10
|
Serikawa T, Mashimo T, Kuramoro T, Voigt B, Ohno Y, Sasa M. Advances on genetic rat models of epilepsy. Exp Anim 2014; 64:1-7. [PMID: 25312505 PMCID: PMC4329510 DOI: 10.1538/expanim.14-0066] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Considering the suitability of laboratory rats in epilepsy research, we and other groups
have been developing genetic models of epilepsy in this species. After epileptic rats or
seizure-susceptible rats were sporadically found in outbred stocks, the epileptic traits
were usually genetically-fixed by selective breeding. So far, the absence seizure models
GAERS and WAG/Rij, audiogenic seizure models GEPR-3 and GEPR-9, generalized tonic-clonic
seizure models IER, NER and WER, and Canavan-disease related epileptic models TRM and SER
have been established. Dissection of the genetic bases including causative genes in these
epileptic rat models would be a significant step toward understanding epileptogenesis.
N-ethyl-N-nitrosourea (ENU) mutagenesis provides a systematic approach which allowed us to
develop two novel epileptic rat models: heat-induced seizure susceptible (Hiss) rats with
an Scn1a missense mutation and autosomal dominant lateral temporal epilepsy (ADLTE) model
rats with an Lgi1 missense mutation. In addition, we have established episodic ataxia type
1 (EA1) model rats with a Kcna1 missense mutation derived from the ENU-induced rat mutant
stock, and identified a Cacna1a missense mutation in a N-Methyl-N-nitrosourea
(MNU)-induced mutant rat strain GRY, resulting in the discovery of episodic ataxia type 2
(EA2) model rats. Thus, epileptic rat models have been established on the two paths:
‘phenotype to gene’ and ‘gene to phenotype’. In the near future, development of novel
epileptic rat models will be extensively promoted by the use of sophisticated genome
editing technologies.
Collapse
Affiliation(s)
- Tadao Serikawa
- Graduate School of Medicine, Kyoto University, Sakyo-ku 606-8501; Laboratory of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki 569-1094, Japan
| | | | | | | | | | | |
Collapse
|
11
|
Leone P, Shera D, McPhee SWJ, Francis JS, Kolodny EH, Bilaniuk LT, Wang DJ, Assadi M, Goldfarb O, Goldman HW, Freese A, Young D, During MJ, Samulski RJ, Janson CG. Long-term follow-up after gene therapy for canavan disease. Sci Transl Med 2013; 4:165ra163. [PMID: 23253610 DOI: 10.1126/scitranslmed.3003454] [Citation(s) in RCA: 178] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Canavan disease is a hereditary leukodystrophy caused by mutations in the aspartoacylase gene (ASPA), leading to loss of enzyme activity and increased concentrations of the substrate N-acetyl-aspartate (NAA) in the brain. Accumulation of NAA results in spongiform degeneration of white matter and severe impairment of psychomotor development. The goal of this prospective cohort study was to assess long-term safety and preliminary efficacy measures after gene therapy with an adeno-associated viral vector carrying the ASPA gene (AAV2-ASPA). Using noninvasive magnetic resonance imaging and standardized clinical rating scales, we observed Canavan disease in 28 patients, with a subset of 13 patients being treated with AAV2-ASPA. Each patient received 9 × 10(11) vector genomes via intraparenchymal delivery at six brain infusion sites. Safety data collected over a minimum 5-year follow-up period showed a lack of long-term adverse events related to the AAV2 vector. Posttreatment effects were analyzed using a generalized linear mixed model, which showed changes in predefined surrogate markers of disease progression and clinical assessment subscores. AAV2-ASPA gene therapy resulted in a decrease in elevated NAA in the brain and slowed progression of brain atrophy, with some improvement in seizure frequency and with stabilization of overall clinical status.
Collapse
Affiliation(s)
- Paola Leone
- Department of Cell Biology, Cell & Gene Therapy Center, University of Medicine & Dentistry of New Jersey, Stratford, NJ 08034, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
|
13
|
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.
Collapse
Affiliation(s)
- Sule Karaman
- Pioneer Hi-Bred, International, Inc., Ankeny, IA 50021-7102, USA
| | | | | | | | | |
Collapse
|
14
|
Scientific Opinion on application (EFSA‐GMO‐UK‐2007‐43) for the placing on the market of herbicide tolerant genetically modified soybean 356043 for food and feed uses, import and processing under Regulation (EC) No 1829/2003 from Pioneer. EFSA J 2011. [DOI: 10.2903/j.efsa.2011.2310] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
15
|
Dionne KR, Leser JS, Lorenzen KA, Beckham JD, Tyler KL. A brain slice culture model of viral encephalitis reveals an innate CNS cytokine response profile and the therapeutic potential of caspase inhibition. Exp Neurol 2011; 228:222-31. [PMID: 21241693 DOI: 10.1016/j.expneurol.2011.01.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 12/30/2010] [Accepted: 01/08/2011] [Indexed: 01/04/2023]
Abstract
Viral encephalitis is a significant cause of human morbidity and mortality in large part due to suboptimal diagnosis and treatment. Murine reovirus infection serves as a classic experimental model of viral encephalitis. Infection of neonatal mice with T3 reoviruses results in lethal encephalitis associated with neuronal infection, apoptosis, and CNS tissue injury. We have developed an ex vivo brain slice culture (BSC) system that recapitulates the basic pathological features and kinetics of viral replication seen in vivo. We utilize the BSC model to identify an innate, brain-tissue specific inflammatory cytokine response to reoviral infection, which is characterized by the release of IL6, CXCL10, RANTES, and murine IL8 analog (KC). Additionally, we demonstrate the potential utility of this system as a pharmaceutical screening platform by inhibiting reovirus-induced apoptosis and CNS tissue injury with the pan-caspase inhibitor, Q-VD-OPh. Cultured brain slices not only serve to model events occurring during viral encephalitis, but can also be utilized to investigate aspects of pathogenesis and therapy that are not experimentally accessible in vivo.
Collapse
Affiliation(s)
- Kalen R Dionne
- Medical Scientist Training Program, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | | | | | | | | |
Collapse
|
16
|
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.
Collapse
Affiliation(s)
- Sule Karaman
- Pioneer Hi-Bred International, Inc., Ankeny, Iowa 50021-7102, USA
| | | | | | | |
Collapse
|
17
|
Pederzolli CD, Rosa AP, de Oliveira AS, Coelho JG, da Luz Becker D, Dalazen GR, Moraes TB, Dutra-Filho CS. Neuroprotective role of lipoic acid against acute toxicity of N-acetylaspartic acid. Mol Cell Biochem 2010; 344:231-9. [DOI: 10.1007/s11010-010-0547-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Accepted: 07/23/2010] [Indexed: 11/28/2022]
|
18
|
Assadi M, Janson C, Wang DJ, Goldfarb O, Suri N, Bilaniuk L, Leone P. Lithium citrate reduces excessive intra-cerebral N-acetyl aspartate in Canavan disease. Eur J Paediatr Neurol 2010; 14:354-9. [PMID: 20034825 DOI: 10.1016/j.ejpn.2009.11.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 10/27/2009] [Accepted: 11/26/2009] [Indexed: 11/18/2022]
Abstract
Our group has previously reported the first clinical application of lithium in a child affected by Canavan disease. In this study, we aimed to assess the effects of lithium on N-acetyl aspartate (NAA) as well as other end points in a larger cohort. Six patients with clinical, laboratory and genetic confirmation of Canavan disease were recruited and underwent treatment with lithium. The battery of safety and efficacy testing performed before and after sixty days of treatment included Gross Motor Function Testing (GMFM), Magnetic Resonance Imaging (MRI) Proton Magnetic Spectroscopy (H-MRS) as well as blood work. The medication was safe without any clinical or laboratory evidence for toxicity. Parental reports indicated improvement in alertness and social interactions. GMFM did not show statistically significant improvement in motor development. H-MRS documented an overall drop in NAA which was statistically significant in the basal ganglia. T1 measurements recorded on MRI studies suggested a mild improvement in myelination in the frontal white matter after treatment. Diffusion Tensor Imaging was available in two patients and suggested micro-structural improvement in the corpus callosum. The results suggest that lithium administration may be beneficial in patients with Canavan disease.
Collapse
Affiliation(s)
- Mitra Assadi
- Robert Wood Johnson Medical School, Neurology, 3 Cooper Plaza, Suite 320, Camden, NJ 08103, USA.
| | | | | | | | | | | | | |
Collapse
|
19
|
Pederzolli CD, Mescka CP, Magnusson AS, Deckmann KB, de Souza Streck E, Sgaravatti AM, Sgarbi MB, Wyse ATS, Wannmacher CMD, Wajner M, Dutra-Filho CS. N-acetylaspartic acid impairs enzymatic antioxidant defenses and enhances hydrogen peroxide concentration in rat brain. Metab Brain Dis 2010; 25:251-9. [PMID: 20437087 DOI: 10.1007/s11011-010-9202-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Accepted: 03/22/2010] [Indexed: 11/27/2022]
Abstract
N-Acetylaspartic acid accumulates in Canavan Disease, a severe inherited neurometabolic disease clinically characterized by severe mental retardation, hypotonia, macrocephaly and generalized tonic and clonic type seizures. Considering that the mechanisms of brain damage in this disease remain poorly understood, in the present study we investigated the in vitro and in vivo effects of N-acetylaspartic acid on the activities of catalase, superoxide dismutase and glutathione peroxidase, as well as on hydrogen peroxide concentration in cerebral cortex of 14-day-old rats. Catalase and glutathione peroxidase activities were significantly inhibited, while hydrogen peroxide concentration was significantly enhanced by N-acetylaspartic acid both in vitro and in vivo. In contrast, superoxide dismutase activity was not altered by N-acetylaspartic acid. Our results clearly show that N-acetylaspartic acid impairs the enzymatic antioxidant defenses in rat brain. This could be involved in the pathophysiological mechanisms responsible for the brain damage observed in patients affected by Canavan Disease.
Collapse
|
20
|
Pederzolli CD, Rockenbach FJ, Zanin FR, Henn NT, Romagna EC, Sgaravatti AM, Wyse ATS, Wannmacher CMD, Wajner M, de Mattos Dutra A, Dutra-Filho CS. Intracerebroventricular administration of N-acetylaspartic acid impairs antioxidant defenses and promotes protein oxidation in cerebral cortex of rats. Metab Brain Dis 2009; 24:283-98. [PMID: 19294497 DOI: 10.1007/s11011-009-9137-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Accepted: 09/29/2008] [Indexed: 01/24/2023]
Abstract
N-acetylaspartic acid (NAA) is the biochemical hallmark of Canavan Disease, an inherited metabolic disease caused by deficiency of aspartoacylase activity. NAA is an immediate precursor for the enzyme-mediated biosynthesis of N-acetylaspartylglutamic acid (NAAG), whose concentration is also increased in urine and cerebrospinal fluid of patients affected by CD. This neurodegenerative disorder is clinically characterized by severe mental retardation, hypotonia and macrocephaly, and generalized tonic and clonic type seizures. Considering that the mechanisms of brain damage in this disease remain not fully understood, in the present study we investigated whether intracerebroventricular administration of NAA or NAAG elicits oxidative stress in cerebral cortex of 30-day-old rats. NAA significantly reduced total radical-trapping antioxidant potential, catalase and glucose 6-phosphate dehydrogenase activities, whereas protein carbonyl content and superoxide dismutase activity were significantly enhanced. Lipid peroxidation indices and glutathione peroxidase activity were not affected by NAA. In contrast, NAAG did not alter any of the oxidative stress parameters tested. Our results indicate that intracerebroventricular administration of NAA impairs antioxidant defenses and induces oxidative damage to proteins, which could be involved in the neurotoxicity of NAA accumulation in CD patients.
Collapse
Affiliation(s)
- Carolina Didonet Pederzolli
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Brasil
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
N-Acetyl-l-aspartate activates hippocampal CA3 neurons in rodent slice preparations. Brain Res Bull 2008; 75:663-7. [DOI: 10.1016/j.brainresbull.2007.10.056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 10/22/2007] [Accepted: 10/26/2007] [Indexed: 11/17/2022]
|
22
|
Acute and repeated dose oral toxicity of N-acetyl-l-aspartic acid in Sprague-Dawley rats. Food Chem Toxicol 2008; 46:2023-34. [PMID: 18329151 DOI: 10.1016/j.fct.2008.01.042] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 01/25/2008] [Accepted: 01/27/2008] [Indexed: 11/22/2022]
Abstract
N-acetyl-l-aspartic acid (NAA) is a constituent of the mammalian central nervous system (CNS) that has been identified in a number of commonly consumed foods. The current study reports the outcome of acute and repeated dose oral toxicology studies conducted with NAA in Sprague-Dawley (SD) rats. No mortalities or evidence of adverse effects were observed in SD rats following acute oral administration of 2000mg/kg NAA. In a separate study, NAA was added to the diets of SD rats (n=10/sex group) at concentrations corresponding to daily doses of 10, 100, or 1000mg/kg/day for 14 consecutive days and 100, 500, and 1000mg/kg/day for another 14 days. All rats survived until scheduled sacrifice and no differences in body weights, feed consumption values, or clinical signs were observed in any of the treatment groups. No biologically significant differences were observed in functional observational battery (FOB), motor activity evaluations, ophthalmologic examinations, hematology, coagulation, clinical chemistry, or organ weights of any of the NAA treatment groups. Further, no test substance-related gross or microscopic changes were observed in NAA exposure groups. Based on these results, NAA was not considered acutely toxic following oral exposure to 2000mg/kg and the no-observed-adverse-effect-level (NOAEL) for systemic toxicity from repeated dose dietary exposure to NAA is 1000mg/kg/day.
Collapse
|
23
|
Gohma H, Kuramoto T, Matalon R, Surendran S, Tyring S, Kitada K, Sasa M, Serikawa T. Absence-like and tonic seizures in aspartoacylase/attractin double-mutant mice. Exp Anim 2007; 56:161-5. [PMID: 17460362 DOI: 10.1538/expanim.56.161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The Spontaneously Epileptic Rat (SER), a double-mutant for tremor and zitter mutations, shows spontaneous occurrences of absence-like and tonic seizures. Several lines of evidence suggest that the combined effect of Aspa and Atrn mutations is the most likely cause of the epileptic phenotype of the SER. To address this issue, we produced a new double-mutant mouse line carrying both homozygous Aspa-knockout and Atrn(mg-3J) mutant alleles. The Aspa/Atrn double-mutant mice exhibited absence-like and tonic seizures that were characterized by the appearance of 5-7 Hz spike-wave-like complexes and low voltage fast waves on EEGs. These results demonstrate directly that the simultaneous loss of the Aspa and Atrn gene functions causes epileptic seizures in the mouse and suggest that both Aspa and Atrn deficiencies might be responsible for epileptic seizures in the SER.
Collapse
Affiliation(s)
- Hiroshi Gohma
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Pederzolli CD, Mescka CP, Scapin F, Rockenbach FJ, Sgaravatti AM, Sgarbi MB, Wyse ATS, Wannmacher CMD, Wajner M, Dutra-Filho CS. N-acetylaspartic acid promotes oxidative stress in cerebral cortex of rats. Int J Dev Neurosci 2007; 25:317-24. [PMID: 17604935 DOI: 10.1016/j.ijdevneu.2007.04.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 04/23/2007] [Accepted: 04/25/2007] [Indexed: 11/18/2022] Open
Abstract
N-acetylaspartic acid accumulates in Canavan Disease, a severe leukodystrophy characterized by swelling and spongy degeneration of the white matter of the brain. This inherited metabolic disease, caused by deficiency of the enzyme aspartoacylase, is clinically characterized by severe mental retardation, hypotonia and macrocephaly, and also generalized tonic and clonic type seizures in about half of the patients. Considering that the mechanisms of brain damage in this disease remain not fully understood, in the present study we investigated whether oxidative stress is elicited by N-acetylaspartic acid. The in vitro effect of N-acetylaspartic acid (10-80 mM) was studied on oxidative stress parameters: total radical-trapping antioxidant potential (TRAP), total antioxidant reactivity (TAR), chemiluminescence, thiobarbituric acid-reactive substances (TBA-RS), reduced glutathione content, sufhydryl content and carbonyl content in the cerebral cortex of 14-day-old rats. The effect of the acute administration of N-acetylaspartic acid (0.1-0.6 mmol/g body weight) was studied on TRAP, TAR, carbonyl content, chemiluminescence and TBA-RS. TRAP, TAR, reduced glutathione content and sulfhydryl content were significantly reduced, while chemiluminescence, TBA-RS and carbonyl content were significantly enhanced by N-acetylaspartic acid in vitro. The enhancement in TBA-RS promoted by N-acetylaspartic acid was completely prevented by ascorbic acid plus Trolox, and partially prevented by glutathione and dithiothreitol. The acute administration of N-acetylaspartic acid also significantly reduced TRAP and TAR, and significantly enhanced carbonyl content, chemiluminescence and TBA-RS. Our results indicate that N-acetylaspartic acid promotes oxidative stress by stimulating lipid peroxidation, protein oxidation and by decreasing non-enzymatic antioxidant defenses in rat brain. This could be another pathophysiological mechanism involved in Canavan Disease.
Collapse
Affiliation(s)
- Carolina D Pederzolli
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600 Anexo, CEP 90035-003, Porto Alegre, RS, Brazil
| | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Yan HD, Ishihara K, Hanaya R, Kurisu K, Serikawa T, Sasa M. Voltage-dependent Calcium Channel Abnormalities in Hippocampal CA3 Neurons of Spontaneously Epileptic Rats. Epilepsia 2007; 48:758-64. [PMID: 17326796 DOI: 10.1111/j.1528-1167.2007.00957.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE Hippocampal CA3 neurons of spontaneously epileptic rats (SER; zi/zi, tm/tm), which show both absence-like seizures and tonic convulsions, exhibit a long-lasting depolarization shift with repetitive firing with a single stimulation of mossy fibers. Therefore a whole-cell patch-clamp study using temporarily dissociated hippocampal CA3 neurons from SER was performed to elucidate whether such abnormal excitability was due to abnormalities in voltage-dependent Ca(2+) channels (VDCCs). METHODS Hippocampal CA3 neurons were temporarily dissociated with enzymatic and mechanical treatments. In a voltage-clamp mode with whole-cell recording, depolarizing step pulses were applied to induce Ca(2+) currents in the presence of tetrodotoxin and tetraethylammonium. RESULTS The threshold level of the Ca(2+) current induced by depolarizing pulses was found to be lower in hippocampal CA3 neurons of SER compared with those of control Wistar rats. In addition, the Ca(2+) current peak amplitude was greater, and decay of the current was weaker in CA3 neurons of SER than in those of normal Wistar rats. CONCLUSIONS These findings suggest that enhancements of Ca(2+) influx into hippocampal CA3 neurons due to the easier activation properties of VDCCs, as well as a decrease in decay, are involved in SER epileptic seizures.
Collapse
Affiliation(s)
- Hai-Dun Yan
- Department of Pharmacology, Hiroshima University School of Medicine, Hrioshima, Japan
| | | | | | | | | | | |
Collapse
|
26
|
Moffett JR, Ross B, Arun P, Madhavarao CN, Namboodiri AMA. N-Acetylaspartate in the CNS: from neurodiagnostics to neurobiology. Prog Neurobiol 2007; 81:89-131. [PMID: 17275978 PMCID: PMC1919520 DOI: 10.1016/j.pneurobio.2006.12.003] [Citation(s) in RCA: 991] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2006] [Revised: 12/07/2006] [Accepted: 12/11/2006] [Indexed: 01/02/2023]
Abstract
The brain is unique among organs in many respects, including its mechanisms of lipid synthesis and energy production. The nervous system-specific metabolite N-acetylaspartate (NAA), which is synthesized from aspartate and acetyl-coenzyme A in neurons, appears to be a key link in these distinct biochemical features of CNS metabolism. During early postnatal central nervous system (CNS) development, the expression of lipogenic enzymes in oligodendrocytes, including the NAA-degrading enzyme aspartoacylase (ASPA), is increased along with increased NAA production in neurons. NAA is transported from neurons to the cytoplasm of oligodendrocytes, where ASPA cleaves the acetate moiety for use in fatty acid and steroid synthesis. The fatty acids and steroids produced then go on to be used as building blocks for myelin lipid synthesis. Mutations in the gene for ASPA result in the fatal leukodystrophy Canavan disease, for which there is currently no effective treatment. Once postnatal myelination is completed, NAA may continue to be involved in myelin lipid turnover in adults, but it also appears to adopt other roles, including a bioenergetic role in neuronal mitochondria. NAA and ATP metabolism appear to be linked indirectly, whereby acetylation of aspartate may facilitate its removal from neuronal mitochondria, thus favoring conversion of glutamate to alpha ketoglutarate which can enter the tricarboxylic acid cycle for energy production. In its role as a mechanism for enhancing mitochondrial energy production from glutamate, NAA is in a key position to act as a magnetic resonance spectroscopy marker for neuronal health, viability and number. Evidence suggests that NAA is a direct precursor for the enzymatic synthesis of the neuron specific dipeptide N-acetylaspartylglutamate, the most concentrated neuropeptide in the human brain. Other proposed roles for NAA include neuronal osmoregulation and axon-glial signaling. We propose that NAA may also be involved in brain nitrogen balance. Further research will be required to more fully understand the biochemical functions served by NAA in CNS development and activity, and additional functions are likely to be discovered.
Collapse
Affiliation(s)
- John R Moffett
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Building C, 4301 Jones Bridge Rd., Bethesda, MD 20814, USA.
| | | | | | | | | |
Collapse
|
27
|
Janson CG, Assadi M, Francis J, Bilaniuk L, Shera D, Leone P. Lithium citrate for Canavan disease. Pediatr Neurol 2005; 33:235-43. [PMID: 16194720 DOI: 10.1016/j.pediatrneurol.2005.04.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Revised: 03/03/2005] [Accepted: 04/04/2005] [Indexed: 11/15/2022]
Abstract
Current evidence suggests that the effects of lithium on metabolic and signaling pathways in the brain may vary depending on the specific clinical condition or disease model. For example, lithium increases levels of cerebral N-acetyl aspartate in patients with bipolar disorder but does not appear to affect N-acetyl aspartate levels in normal human subjects. Conversely, lithium significantly decreases whole-brain levels of N-acetyl aspartate in a rat genetic model of Canavan disease in which cerebral N-acetyl aspartate is chronically elevated. While N-acetyl aspartate is a commonly used surrogate marker for neuronal density and correlates with neuronal viability, grossly elevated whole-brain levels of N-acetyl aspartate in Canavan disease are associated with dysmyelination and mental retardation. This report describes the first clinical application of lithium in a human subject with Canavan disease. Spectroscopic and clinical changes were observed over the time period in which lithium was administered, which reversed during a 2-week wash-out period after withdrawal of lithium. This investigation reports decreased N-acetyl aspartate levels in the brain regions tested and magnetic resonance spectroscopic values that are more characteristic of normal development and myelination, suggesting that a larger, controlled trial of lithium may be warranted as supportive therapy for Canavan disease by decreasing abnormally elevated N-acetyl aspartate.
Collapse
Affiliation(s)
- Christopher G Janson
- Department of Neurosurgery and Molecular Genetics, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Camden, USA
| | | | | | | | | | | |
Collapse
|
28
|
Yan HD, Ji-qun C, Ishihara K, Nagayama T, Serikawa T, Sasa M. Separation of Antiepileptogenic and Antiseizure Effects of Levetiracetam in the Spontaneously Epileptic Rat (SER). Epilepsia 2005; 46:1170-7. [PMID: 16060925 DOI: 10.1111/j.1528-1167.2005.35204.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
PURPOSE The long-lasting antiseizure effects of levetiracetam (LEV) have been observed in the spontaneously epileptic rat (SER) that expresses both tonic and absence-like seizures. Furthermore, the antiepileptogenic effects of LEV in addition to antiseizure effects have been reported in the amygdala-kindling model in rats. This suggests that the long-lasting seizure protection of LEV may be at least partly due to its antiepileptogenic effects. Therefore this study aimed to differentiate the antiseizure and potential antiepileptogenic effects of LEV by administering LEV continuously to SERs before the appearance of any seizure expression. METHODS LEV was administered to the SERs at 80 mg/kg/day (i.p.) from postnatal weeks 5 to 8. The period of observation for tonic convulsions was from postnatal week 5 to 13. Absence-like seizures were recorded by using conventional EEG in weeks 12 and 13. RESULTS After age 7-8 weeks, SERs exhibit spontaneous tonic convulsions. Development of tonic convulsions was significantly inhibited in the LEV group, compared with the control group, by the middle of week 9. A significant reduction of tonic convulsions also was observed in the LEV group until week 13 (5 weeks after termination of the administration). In week 12, the absence-like seizures were significantly lower in the LEV group, compared with the control group. CONCLUSIONS This study demonstrates a significant inhibition of seizures after prolonged treatment with LEV before the developmental expression of seizure activity in SERs. This effect is suggested to be due to an antiepileptogenic effect and not an antiseizure effect of LEV, because the half-life of the drug in plasma is short (2-3 h in rats) after single and long-term administration. Furthermore, the inhibition of seizure expression in SERs was still apparent 5 weeks after termination of LEV treatment. These results further suggest that LEV possesses not only antiseizure effects but also antiepileptogenic properties.
Collapse
Affiliation(s)
- Hai-Dun Yan
- Department of Pharmacology, Hiroshima University School of Medicine, Hiroshima, Japan
| | | | | | | | | | | |
Collapse
|
29
|
Klugmann M, Leichtlein CB, Symes CW, Serikawa T, Young D, During MJ. Restoration of aspartoacylase activity in CNS neurons does not ameliorate motor deficits and demyelination in a model of Canavan disease. Mol Ther 2005; 11:745-53. [PMID: 15851013 DOI: 10.1016/j.ymthe.2005.01.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2004] [Accepted: 01/06/2005] [Indexed: 10/25/2022] Open
Abstract
Canavan disease is an early onset leukodystrophy associated with psychomotor retardation, seizures, and premature death. This disorder is caused by mutations in the gene encoding the enzyme aspartoacylase (ASPA). Normally, ASPA is enriched in oligodendrocytes and ASPA deficiency results in elevated levels of its substrate molecule, N-acetylaspartate (NAA), brain edema, and dysmyelination. Using adeno-associated virus, we permanently expressed ASPA in CNS neurons of the tremor rat, a genetic model of Canavan disease, and examined the efficacy of the treatment by monitoring NAA metabolism, myelination, motor behavior, and seizures. Assessment of ASPA protein and enzyme activity in whole brain hemispheres showed restoration to normal levels as long as 6 months after treatment. This finding correlated with a reduction of NAA levels, along with a rescue of the seizure phenotype. However, gross brain pathology, such as dilated ventricles and spongiform vacuolization, was unchanged. Moreover, hypomyelination and motor deficits were not resolved by ASPA gene transfer. Our data suggest that NAA-mediated neuronal hyperexcitation but not oligodendrocyte dysfunction can be compensated for by neuronal ASPA expression.
Collapse
Affiliation(s)
- Matthias Klugmann
- Laboratory of Functional Genomics and Translational Neuroscience, Department of Molecular Medicine and Pathology, University of Auckland School of Medicine, 85 Park Road, Auckland, New Zealand.
| | | | | | | | | | | |
Collapse
|
30
|
McPhee SWJ, Francis J, Janson CG, Serikawa T, Hyland K, Ong EO, Raghavan SS, Freese A, Leone P. Effects of AAV-2-mediated aspartoacylase gene transfer in the tremor rat model of Canavan disease. ACTA ACUST UNITED AC 2005; 135:112-21. [PMID: 15857674 DOI: 10.1016/j.molbrainres.2004.12.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2004] [Revised: 11/15/2004] [Accepted: 12/05/2004] [Indexed: 11/26/2022]
Abstract
The tremor rat is a spontaneous epilepsy model with a seizure phenotype caused by a deletion in the aspartoacylase (ASPA) gene. The absence of ASPA expression in these animals results in undetectable levels of enzyme activity and the accumulation of the substrate N-acetyl-aspartate (NAA) in brain, leading to generalized myelin vacuolation and severe motor and cognitive impairment. In support of human gene therapy for CD, recombinant adeno-associated viral vector (AAV-2) expressing ASPA was stereotactically delivered to the tremor rat brain and effects on the mutant phenotype were measured. AAV-ASPA gene transfer resulted in elevated aspartoacylase bioactivity compared to untreated mutant animals and elicited a significant decrease in the pathologically elevated whole-brain NAA levels. Assessment of motor function via quantitative rotorod testing demonstrated that rats injected with AAV-ASPA significantly improved on tests of balance and coordinated locomotion compared to animals receiving control vectors. This study provides evidence that AAV-2-mediated aspartoacylase gene transfer to the brain improves biochemical and behavioral deficits in tremor rat mutants (tm/tm) and supports the rationale of human gene transfer for Canavan disease.
Collapse
Affiliation(s)
- S W J McPhee
- Cell and Gene Therapy Center, UMDNJ-Robert Wood Johnson Medical School, 401 Haddon Avenue, Suite #395, Camden, NJ 08103, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Tranberg M, Stridh MH, Guy Y, Jilderos B, Wigström H, Weber SG, Sandberg M. NMDA-receptor mediated efflux of N-acetylaspartate: physiological and/or pathological importance? Neurochem Int 2004; 45:1195-204. [PMID: 15380629 DOI: 10.1016/j.neuint.2004.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2004] [Accepted: 06/03/2004] [Indexed: 10/26/2022]
Abstract
N-Acetylaspartate (NAA) is a largely neuron specific dianionic amino acid present in high concentration in vertebrate brain. Many fundamental questions concerning N-acetylaspartate in brain remain unanswered. One such issue is the predominantly neuronal synthesis and largely glial catabolism which implies the existence of a regulated efflux from neurons. Here we show that transient (5 min) NMDA-receptor activation (60 microM) induces a long lasting Ca2+ -dependent efflux of N-acetylaspartate from organotypic slices of rat hippocampus. The NMDA-receptor stimulated efflux was unaffected by hyper-osmotic conditions (120 mM sucrose) and no efflux of N-acetylaspartate was evoked by high K+ -depolarization (50 mM) or kainate (300 microM). These results indicate that the efflux induced by NMDA is not related directly to either cell swelling or depolarization but is coupled to Ca2+ -influx via the NMDA-receptor. The efflux of N-acetylaspartate persisted at least 20 min after the omission of NMDA, similar to the efflux of the organic anions glutathione and phosphoethanolamine. The efflux of taurine and hypotaurine was also stimulated by NMDA but returned more quickly to basal levels. The NMDA-receptor stimulated efflux of N-acetylaspartate, glutathione, phosphoethanolamine, taurine and hypotaurine correlated with delayed nerve cell death measured 24 h after the transient NMDA-receptor stimulation. However, exogenous administration of high concentrations of N-acetylaspartate to the culture medium was non-toxic. The results suggest that Ca2+ -influx via the NMDA-receptor regulates the efflux of N-acetylaspartate from neurons which may have both physiological and pathological importance.
Collapse
Affiliation(s)
- Mattias Tranberg
- Department of Medical Biophysics, Göteborg University, Göteborg, Sweden
| | | | | | | | | | | | | |
Collapse
|
32
|
Klugmann M, Symes CW, Klaussner BK, Leichtlein CB, Serikawa T, Young D, During MJ. Identification and distribution of aspartoacylase in the postnatal rat brain. Neuroreport 2003; 14:1837-40. [PMID: 14534431 DOI: 10.1097/00001756-200310060-00016] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Aspartoacylase metabolizes N-acetylaspartic acid to produce L-aspartate and acetate. An aspartoacylase deficiency in humans is responsible for Canavan disease, a lethal autosomal recessive leukodystrophy. The role of aspartoacylase in the mammalian brain is unclear. Here we have generated and characterized a highly specific polyclonal antibody against aspartoacylase which recognizes a 37 kDa monomer and a dimer in normal but not in aspartoacylase-deficient rat tissue. Aspartoacylase protein expression sharply increases at P14, peaks at P28 and plateaus thereafter. Biochemical analysis reveals immunoreactivity in cytosolic but not in membrane fractions. Histologically, most abundant expression was observed in white matter tracts and thalamus. On the cellular level, aspartoacylase immunoreactivity is restricted to oligodendrocyte somata in both white and gray matter.
Collapse
Affiliation(s)
- Matthias Klugmann
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand. m.
| | | | | | | | | | | | | |
Collapse
|
33
|
Yan HD, Ishihara K, Serikawa T, Sasa M. Activation by N-acetyl-L-aspartate of acutely dissociated hippocampal neurons in rats via metabotropic glutamate receptors. Epilepsia 2003; 44:1153-9. [PMID: 12919386 DOI: 10.1046/j.1528-1157.2003.49402.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE We previously reported that an increase in the N-acetyl-L-aspartate (NAA) level due to the lack of aspartoacylase gene was found in the brain of the tremor rat (tm/tm), which is a mutant with a causative gene named tm that shows epileptic seizures. Therefore, NAA is suggested to be one of the factors involved in the induction of epileptic seizures. Patch-clamp studies were performed to determine whether NAA produces an excitatory effect on acutely dissociated rat hippocampal neurons. METHODS Acutely dissociated hippocampal neurons were prepared from normal Wistar rats aged 3-4 weeks. NAA-induced currents were investigated by using the whole-cell voltage-clamp recording technique. RESULTS Application of NAA at concentrations of 100 nM to 1 mM through a U-tube for 2 s produced an inward current in a concentration-dependent manner at a holding potential of -60 mV. When the current-voltage relation was examined, the reversal potential of the NAA-induced current was found to be approximately 0 mV. The NAA-induced current was inhibited by bath application of the metabotropic glutamate receptor (mGluR) antagonist (+/-)-alpha-methyl-4-carboxyphenylglycine (MCPG) and by intracellular application of guanosine 5'-O-(2-thiodiphosphate) (GDP-betaS), a nonhydrolyzable GDP analogue. However, the NAA-induced current remained unaffected by glutamic acid diethyl ester, a non-N-methyl-D-aspartate (NMDA)-subtype ionotropic glutamate receptor antagonist, or the voltage-dependent ion channel blockers tetrodotoxin, CdCl2, and tetraethylammonium-chloride. Conversely, the mGluR agonist, trans-(1S,3R)-1-amino-1,3-cyclopentanedicarboxylic acid (ACPD) also induced an inward current, with a reversal potential of 0 mV. The ACPD-induced current also was inhibited by MCPG. CONCLUSIONS These results suggest that NAA acts on the G protein-coupled mGluRs to induce an inward current that results in excitation of the neurons, thereby contributing to the occurrence of epileptic seizures.
Collapse
Affiliation(s)
- Hai-Dun Yan
- Department of Pharmacology, Hiroshima University School of Medicine, Hiroshima, Japan
| | | | | | | |
Collapse
|
34
|
Seki T, Matsubayashi H, Amano T, Kitada K, Serikawa T, Sakai N, Sasa M. Adenoviral gene transfer of aspartoacylase into the tremor rat, a genetic model of epilepsy, as a trial of gene therapy for inherited epileptic disorder. Neurosci Lett 2002; 328:249-52. [PMID: 12147318 DOI: 10.1016/s0304-3940(02)00522-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The tremor rat (tm/tm) is a genetic model of epilepsy that exhibits absence-like seizures characterized by 5-7 Hz spike-wave-like complexes in cortical and hippocampal electroencephalograms (EEGs). A deletion of the aspartoacylase (ASPA) gene and resultant high levels of N-acetyl-aspartate (NAA) in the brain have been found in tremor rats. We attempted to determine whether gene transfer of ASPA inhibited absence-like seizures in tremor rats using recombinant adenovirus. Recombinant adenovirus (5x10(7) pfu) carrying the rat ASPA gene (AxASPA) or beta-galactosidase gene (AxLacZ), as a control virus, was intracerebroventricularly administered to premature tremor rats aged 7 weeks. Cortical and hippocampal EEG were recorded with chronically implanted electrodes before and after viral administration. The absence-like seizures were increased in AxLacZ-administered control rats with age. However, the increase was significantly inhibited in AxASPA-administered rats at 1 week after treatment. These results suggest that gene transfer of ASPA is effective in inhibiting the generation of absence-like seizures, probably by reducing the NAA level.
Collapse
Affiliation(s)
- Takahiro Seki
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical Sciences, Hiroshima University, Minami-ku, 1-2-3 Kasumi, 734-8551, Hiroshima, Japan.
| | | | | | | | | | | | | |
Collapse
|
35
|
Ferraz AC, Anselmo-Franci JA, Perosa SR, de Castro-Neto EF, Bellissimo MI, de Oliveira BH, Cavalheiro EA, Naffah-Mazzacoratti MDG, Da Cunha C. Amino acid and monoamine alterations in the cerebral cortex and hippocampus of mice submitted to ricinine-induced seizures. Pharmacol Biochem Behav 2002; 72:779-86. [PMID: 12062566 DOI: 10.1016/s0091-3057(02)00750-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The alkaloid ricinine isolated from the plant Ricinus communis, when administered to mice at high doses, induces clonic seizures accompanied by electroencephalographic alterations in the cerebral cortex and hippocampus. The lethal nature of ricinine-induced seizures is considered to be a good model for the study of the events that cause death during clonic seizures, particularly those related to respiratory spasms. The initial signs (pre-seizure period) were marked by exophthalmus and decreased locomotor behavior. Animals killed during the preseizure period presented an increased utilization rate (HVA/DA) of dopamine (DA), an increased concentration of noradrenaline (NA), and a decreased concentration of glutamate (Glu), glutamine (Gln), taurine (Tau), and serotonin (5-HT) in the cerebral cortex. The seizure period is characterized by the occurrence of hind limb myoclonus and respiratory spasms, which are followed by death. Alterations in the cerebral cortex concentration of these neurotransmitters persisted during the seizure period. These alterations are only partially observed in the hippocampus, mainly during the seizure period. The present results suggest that an increased release of Glu in the cerebral cortex can be implicated in the genesis of the ricinine-induced seizure and that it triggers many anticonvulsive mechanisms, like the release of Tau, DA, 5-HT, and NA.
Collapse
Affiliation(s)
- Anete C Ferraz
- Laboratório de Fisiologia e Farmacologia do SNC, Departamento de Fisiologia e Departamento de Farmacologia, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Nakane Y, Adachi T, Voigt B, Yamasaki KI, Kaji S, Inui T, Kitada K, Serikawa T. A novel mutation vf causing abnormal vacuoles in the central nervous system maps on rat chromosome 8. Exp Anim 2002; 51:149-55. [PMID: 12012723 DOI: 10.1538/expanim.51.149] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Body-tremorous rats were found in a colony of WTC-tm rats and a new coisogenic mutant strain void of the tm mutation was established. Histological analysis revealed that these rat mutants had abnormal vacuoles in the red nucleus of the midbrain, the reticular formation in the brain stem, and the white matter of the cerebellum and spinal cord. Electron microscopic observation showed many irregular myelin-bound vacuoles and degenerated oligodendroglia. Genetic analysis indicated that the presence of the abnormal vacuoles in the central nervous system (CNS) is controlled by a recessive gene named "vacuole formation (vf)" on chromosome (Chr) 8, and that this gene is also involved in the appearance of body tremors. Comparative maps suggested that the mouse and human orthologs would be located on Chr 9 (43-48 cM) and Chr 6 (328-370 cR3000), respectively. Since similar mutations have not been mapped yet around these regions, the authors believe this novel rat mutation will allow the discovery of a new function of these particular genes that is involved in the development and maintenance of the CNS.
Collapse
Affiliation(s)
- Yoshifumi Nakane
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Yoshida-Konoe-Cho, Sakyo-Ku, Kyoto 606-8501, Japan
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Bhakoo KK, Craig TJ, Styles P. Developmental and regional distribution of aspartoacylase in rat brain tissue. J Neurochem 2001; 79:211-20. [PMID: 11595773 DOI: 10.1046/j.1471-4159.2001.00561.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The function of N-acetyl-aspartate (NAA), a predominant molecule in the brain, has not yet been determined. However, NAA is commonly used as a putative marker of viable neurones. To investigate the possible function of NAA, we determined the anatomical, developmental and cellular distribution of aspartoacylase, which catalyses the hydrolysis of NAA. Levels of aspartoacylase activity were measured during postnatal development in several brain regions. The differential distribution of aspartoacylase activity in purified populations of cells derived from the rat CNS was also investigated. The developmental and anatomical distribution of aspartoacylase correlated with the maturation of white matter tracts in the rat brain. Activity increased markedly after 7 days and coincided with the time course for the onset of myelination in the rat brain. Gray matter showed little activity or developmental trend. There was a 60-fold excess in optic nerve (a white matter tract) when compared with cortex at 21 days of development. In the adult brain there was a 18-fold difference in corpus callosum compared with cortex (stripped of corpus callosum). Cellular studies demonstrated that purified cortical neurons and cerebellar granular neurones have no activity. Primary O-2A progenitor cells had moderate activity, with three-fold higher activity in immature oligodendrocyte and 13-fold increase in mature oligodendrocytes (myelinating cells of the CNS). The highest activity was seen in type-2 astrocytes (20-fold difference compared with O-2A progenitors) derived from the same source. Aspartoacylase activity increased with time in freshly isolated astrocytes, with significantly higher activity after 15 days in culture. We conclude that aspartoacylase activity in the developing postnatal brain corresponds with maturation of myelination, and that the cellular distribution is limited to glial cells.
Collapse
Affiliation(s)
- K K Bhakoo
- MRC Biochemical and Clinical Magnetic Resonance Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford.
| | | | | |
Collapse
|
38
|
Baslow MH, Suckow RF, Hungund BL. Effects of ethanol and of alcohol dehydrogenase inhibitors on the reduction of N-acetylaspartate levels of brain in mice in vivo: a search for substances that may have therapeutic value in the treatment of Canavan disease. J Inherit Metab Dis 2000; 23:684-92. [PMID: 11117430 DOI: 10.1023/a:1005618526988] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
N-Acetylaspartate (NAA) is an important osmolyte in the vertebrate brain that participates in an intercompartmental metabolic cycle. It is synthesized primarily in neurons from L-aspartate (Asp) and acetyl-CoA and, after its regulated release, it is hydrolysed by aspartoacylase in an oligodendrocyte compartment to produce Asp and acetate. NAA also gives a strong 1H magnetic resonance spectroscopic signal, which has led to its widespread use as a neuronal marker. Utilizing this noninvasive technique, the NAA concentrations in normal brain and in brains exhibiting a variety of CNS disease syndromes have been studied. In normal individuals, the concentration of NAA has been observed to be relatively stable over long periods. However, in many CNS disease processes there are long-term changes in the level of NAA that have been considered to signal changes in neuron density or function. We report that the concentration of NAA in brain is malleable and that, in addition to normal endogenous variation or changes due to disease processes, it can be modified by a variety of exogenous drugs and other substances. As a result of this investigation, we have also been able to identify a new class of NAA-active compounds--pyrazole and pyrazole derivatives--that have the ability to reduce brain NAA concentrations in normal mice. The importance of these findings in understanding the NAA intercompartmental cycle, and its role in Canavan disease, a genetic aspartoacylase deficiency disease, are discussed.
Collapse
Affiliation(s)
- M H Baslow
- Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York 10962, USA.
| | | | | |
Collapse
|
39
|
Maihara T, Noda A, Yamazoe H, Voigt B, Kitada K, Serikawa T. Chromosomal mapping of genes for epilepsy in NER: a rat strain with tonic-clonic seizures. Epilepsia 2000; 41:941-9. [PMID: 10961618 DOI: 10.1111/j.1528-1157.2000.tb00276.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE NER is a mutant rat strain that exhibits spontaneous tonic-clonic convulsions accompanied by epileptic discharges on ictal EEG and serves as a model for generalized tonic-clonic seizures in humans. Our previous experiments have suggested that a major autosomal recessive gene and several minor genes regulate the inheritance of tonic-clonic seizures in NER. The purpose of this study was to confirm the mode of inheritance and to locate the causative genes for epilepsy in NER on the rat genetic map. METHODS We developed F1 hybrid (F1) and reciprocal back-cross progenies of NER with a seizure-resistant strain, F344, and evaluated their seizure susceptibility under tossing-stimulated and nonstimulated conditions. Backcross animals were genotyped using simple sequence length polymorphism markers for polymerase chain reactions. Linkage between seizure susceptibility and marker loci was analyzed by chi2 statistic tests and by the computer programs MAPMAKER/EXP and MAPMAKER/QTL. RESULTS Under tossing-stimulating conditions, tonic-clonic seizures were provoked in 90% of NER and 66% of (F1 x NER) backcross animals, but no seizures occurred in the F344, F1, or (F1 x F344) backcross animals. Routine monitoring of nonstimulated animals revealed spontaneous tonic-clonic convulsions in 100% of NER and 64.2% of (F1 x NER) backcross animals, but no seizures in F344 or F1. Gender effect on seizure susceptibility was negligible in (F1 x NER) backcross in both conditions. Preliminary genome-wide scanning and subsequent precise location of the causative genes revealed seizure susceptibility loci, designated Ner1 and Ner2, on rat chromosomes 1 and 3, respectively. CONCLUSIONS Ner1 is a locus that controls the inheritance of spontaneous tonic-clonic seizures in an autosomal recessive mode, whereas Ner2 affects the occurrence of tossing-induced seizures. Orthologous genes in the vicinity of these loci may be related to epileptogenesis in other species, including humans.
Collapse
Affiliation(s)
- T Maihara
- Institute of Laboratory Animals and Department of Pediatrics, Graduate School of Medicine, Kyoto University, Japan
| | | | | | | | | | | |
Collapse
|
40
|
Kitada K, Akimitsu T, Shigematsu Y, Kondo A, Maihara T, Yokoi N, Kuramoto T, Sasa M, Serikawa T. Accumulation of N-acetyl-L-aspartate in the brain of the tremor rat, a mutant exhibiting absence-like seizure and spongiform degeneration in the central nervous system. J Neurochem 2000; 74:2512-9. [PMID: 10820213 DOI: 10.1046/j.1471-4159.2000.0742512.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The tremor rat is a mutant that exhibits absence-like seizure and spongiform degeneration in the CNS. By positional cloning, a genomic deletion was found within the critical region in which the aspartoacylase gene is located. Accordingly, no aspartoacylase expression was detected in any of the tissues examined, and abnormal accumulation of N-acetyl-L-aspartate (NAA) was shown in the mutant brain, in correlation with the severity of the vacuole formation. Therefore, the tremor rat may be regarded as a suitable animal model of human Canavan disease, characterized by spongy leukodystrophy that is caused by aspartoacylase deficiency. Interestingly, direct injection of NAA into normal rat cerebroventricle induced 4- to 10-Hz polyspikes or spikewave-like complexes in cortical and hippocampal EEG, concomitantly with behavior characterized by sudden immobility and staring. These results suggested that accumulated NAA in the CNS would induce neuroexcitation and neurodegeneration directly or indirectly.
Collapse
Affiliation(s)
- K Kitada
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|