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Tokatly Latzer I, Roullet JB, Afshar-Saber W, Lee HHC, Bertoldi M, McGinty GE, DiBacco ML, Arning E, Tsuboyama M, Rotenberg A, Opladen T, Jeltsch K, García-Cazorla À, Juliá-Palacios N, Gibson KM, Sahin M, Pearl PL. Clinical and molecular outcomes from the 5-Year natural history study of SSADH Deficiency, a model metabolic neurodevelopmental disorder. J Neurodev Disord 2024; 16:21. [PMID: 38658850 PMCID: PMC11044349 DOI: 10.1186/s11689-024-09538-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 04/09/2024] [Indexed: 04/26/2024] Open
Abstract
BACKGROUND Succinic semialdehyde dehydrogenase deficiency (SSADHD) represents a model neurometabolic disease at the fulcrum of translational research within the Boston Children's Hospital Intellectual and Developmental Disabilities Research Centers (IDDRC), including the NIH-sponsored natural history study of clinical, neurophysiological, neuroimaging, and molecular markers, patient-derived induced pluripotent stem cells (iPSC) characterization, and development of a murine model for tightly regulated, cell-specific gene therapy. METHODS SSADHD subjects underwent clinical evaluations, neuropsychological assessments, biochemical quantification of γ-aminobutyrate (GABA) and related metabolites, electroencephalography (standard and high density), magnetoencephalography, transcranial magnetic stimulation, magnetic resonance imaging and spectroscopy, and genetic tests. This was parallel to laboratory molecular investigations of in vitro GABAergic neurons derived from induced human pluripotent stem cells (hiPSCs) of SSADHD subjects and biochemical analyses performed on a versatile murine model that uses an inducible and reversible rescue strategy allowing on-demand and cell-specific gene therapy. RESULTS The 62 SSADHD subjects [53% females, median (IQR) age of 9.6 (5.4-14.5) years] included in the study had a reported symptom onset at ∼ 6 months and were diagnosed at a median age of 4 years. Language developmental delays were more prominent than motor. Autism, epilepsy, movement disorders, sleep disturbances, and various psychiatric behaviors constituted the core of the disorder's clinical phenotype. Lower clinical severity scores, indicating worst severity, coincided with older age (R= -0.302, p = 0.03), as well as age-adjusted lower values of plasma γ-aminobutyrate (GABA) (R = 0.337, p = 0.02) and γ-hydroxybutyrate (GHB) (R = 0.360, p = 0.05). While epilepsy and psychiatric behaviors increase in severity with age, communication abilities and motor function tend to improve. iPSCs, which were differentiated into GABAergic neurons, represent the first in vitro neuronal model of SSADHD and express the neuronal marker microtubule-associated protein 2 (MAP2), as well as GABA. GABA-metabolism in induced GABAergic neurons could be reversed using CRISPR correction of the pathogenic variants or mRNA transfection and SSADHD iPSCs were associated with excessive glutamatergic activity and related synaptic excitation. CONCLUSIONS Findings from the SSADHD Natural History Study converge with iPSC and animal model work focused on a common disorder within our IDDRC, deepening our knowledge of the pathophysiology and longitudinal clinical course of a complex neurodevelopmental disorder. This further enables the identification of biomarkers and changes throughout development that will be essential for upcoming targeted trials of enzyme replacement and gene therapy.
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Affiliation(s)
- Itay Tokatly Latzer
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA
- School of Medicine, Faculty of Medical and Health Sciences, Tel-Aviv University, Tel Aviv, Israel
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Wardiya Afshar-Saber
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA, 02115, USA
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Henry H C Lee
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA, 02115, USA
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Mariarita Bertoldi
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Gabrielle E McGinty
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Melissa L DiBacco
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA
| | - Erland Arning
- Institute of Metabolic Disease, Baylor Scott & White Research Institute, Dallas, TX, USA
| | - Melissa Tsuboyama
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA
| | - Alexander Rotenberg
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Thomas Opladen
- Division of Neuropediatrics & Metabolic Medicine, University Children's Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Kathrin Jeltsch
- Division of Neuropediatrics & Metabolic Medicine, University Children's Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Àngels García-Cazorla
- Neurometabolic Unit, Neurology Department, Institut de Recerca, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Natalia Juliá-Palacios
- Neurometabolic Unit, Neurology Department, Institut de Recerca, Hospital Sant Joan de Déu, Barcelona, Spain
| | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Mustafa Sahin
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA, 02115, USA
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Phillip L Pearl
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA.
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Pearl PL, Tokatly Latzer I, Lee HHC, Rotenberg A. New Therapeutic Approaches to Inherited Metabolic Pediatric Epilepsies. Neurology 2023; 101:124-133. [PMID: 36878704 PMCID: PMC10382274 DOI: 10.1212/wnl.0000000000207133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 01/17/2023] [Indexed: 03/08/2023] Open
Abstract
Treatment options for inherited metabolic epilepsies are rapidly expanding with advances in molecular biology and the genomic revolution. Traditional dietary and nutrient modification and inhibitors or enhancers of protein and enzyme function, the mainstays of therapy, are undergoing continuous revisions to increase biological activity and reduce toxicity. Enzyme replacement and gene replacement and editing hold promise for genetically targeted treatment and cures. Molecular, imaging, and neurophysiologic biomarkers are emerging as key indicators of disease pathophysiology, severity, and response to therapy.
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Affiliation(s)
- Phillip L Pearl
- From the Department of Neurology (P.L.P., I.T.L., H.H.C.L., A.R.), Boston Children's Hospital, Harvard Medical School, Boston, MA.
| | - Itay Tokatly Latzer
- From the Department of Neurology (P.L.P., I.T.L., H.H.C.L., A.R.), Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Henry H C Lee
- From the Department of Neurology (P.L.P., I.T.L., H.H.C.L., A.R.), Boston Children's Hospital, Harvard Medical School, Boston, MA
| | - Alexander Rotenberg
- From the Department of Neurology (P.L.P., I.T.L., H.H.C.L., A.R.), Boston Children's Hospital, Harvard Medical School, Boston, MA
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Tsuboyama M, Liu J, Kaye H, DiBacco M, Pearl PL, Rotenberg A. Transcranial Magnetic Stimulation in Succinic Semialdehyde Dehydrogenase Deficiency: A Measure of Maturational Trajectory of Cortical Excitability. J Child Neurol 2021; 36:1169-1176. [PMID: 34058900 PMCID: PMC8630082 DOI: 10.1177/08830738211008735] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a disorder of GABA degradation with use-dependent downregulation of postsynaptic GABAA/B receptors. We aim to measure the resulting cortical excitation: inhibition ratio using transcranial magnetic stimulation. METHODS In this single-center observational study, 18 subjects with SSADHD and 8 healthy controls underwent transcranial magnetic stimulation. Resting motor threshold, cortical silent period, and long-interval intracortical inhibition were measured in both groups. Resting motor threshold in focal epilepsy patients from an institutional transcranial magnetic stimulation database were also included. RESULTS SSADHD subjects had higher resting motor threshold than healthy controls but lower relative to focal epilepsy patients. Resting motor threshold decreased with age in all groups. Cortical silent period was longer in SSADHD subjects than in healthy controls. No difference was detected in long-interval intracortical inhibition between the 2 groups. CONCLUSION Findings suggest abnormal corticospinal tract physiology in SSADHD, but with preserved developmental trajectory for corticospinal tract maturation. Defining features of these transcranial magnetic stimulation metrics in SSADHD will be better elucidated through this ongoing longitudinal study.
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Affiliation(s)
- Melissa Tsuboyama
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, 1862Boston Children's Hospital, Boston, MA, USA
| | - Jingjing Liu
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, 1862Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, 1862Boston Children's Hospital, Boston, MA, USA
| | - Harper Kaye
- 12259Boston University School of Medicine, Behavioral Neuroscience Program, Boston, MA, USA
| | - Melissa DiBacco
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, 1862Boston Children's Hospital, Boston, MA, USA
| | - Phillip L Pearl
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, 1862Boston Children's Hospital, Boston, MA, USA
| | - Alexander Rotenberg
- Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, 1862Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, 1862Boston Children's Hospital, Boston, MA, USA.,Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA
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4
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Schreiber JM, Wiggs E, Cuento R, Norato G, Dustin IH, Rolinski R, Austermuehle A, Zhou X, Inati SK, Gibson KM, Pearl PL, Theodore WH. A Randomized Controlled Trial of SGS-742, a γ-aminobutyric acid B (GABA-B) Receptor Antagonist, for Succinic Semialdehyde Dehydrogenase Deficiency. J Child Neurol 2021; 36:1189-1199. [PMID: 34015244 PMCID: PMC8605041 DOI: 10.1177/08830738211012804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We examined safety, tolerability, and efficacy of SGS-742, a γ-aminobutyric acid B (GABA-B) receptor antagonist, in patients with succinic semialdehyde dehydrogenase deficiency. This was a single-center randomized, double-blind crossover phase II clinical trial of SGS-742 versus placebo in patients with succinic semialdehyde dehydrogenase deficiency. Procedures included transcranial magnetic stimulation and the Adaptive Behavior Assessment Scale. Nineteen subjects were consented and enrolled; the mean age was 14.0 ± 7.5 years and 11 (58%) were female. We did not find a significant effect of SGS-742 on the Adaptive Behavior Assessment Scale score, motor threshold, and paired-pulse stimulation. The difference in recruitment curve slopes between treatment groups was 0.003 (P = .09). There was no significant difference in incidence of adverse effects between drug and placebo arms. SGS-742 failed to produce improved cognition and normalization of cortical excitability as measured by the Adaptive Behavior Assessment Scale and transcranial magnetic stimulation. Our data do not support the current use of SGS-742 in succinic semialdehyde dehydrogenase deficiency.Trial registry number NCT02019667. Phase 2 Clinical Trial of SGS-742 Therapy in Succinic Semialdehyde Dehydrogenase Deficiency. https://clinicaltrials.gov/ct2/show/NCT02019667.
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Affiliation(s)
- John M. Schreiber
- NINDS NIH, Clinical Epilepsy Section, Bethesda, MD, USA
- Children’s National Hospital, Division of Epilepsy, Neurophysiology, and Critical Care Neurology, Washington, DC, USA
| | - Edythe Wiggs
- NINDS NIH, Office of the Clinical Director, Bethesda, MD, USA
| | - Rose Cuento
- NINDS NIH, Office of the Clinical Director, Bethesda, MD, USA
- NINDS NIH, Clinical Trials Unit, Bethesda, MD, USA
| | - Gina Norato
- NINDS NIH, Office of the Clinical Director, Bethesda, MD, USA
| | | | | | | | | | - Sara K. Inati
- NINDS NIH, Office of the Clinical Director, Bethesda, MD, USA
| | - K. Michael Gibson
- Washington State University, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacotherapy, Spokane, WA, USA
| | - Phillip L. Pearl
- Boston Children’s Hospital, Department of Epilepsy and Clinical Neurophysiology, Boston, MA, USA
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Walters DC, Lawrence R, Kirby T, Ahrendsen JT, Anderson MP, Roullet JB, Murphy EJ, Gibson KM. Postmortem Analyses in a Patient With Succinic Semialdehyde Dehydrogenase Deficiency (SSADHD): II. Histological, Lipid, and Gene Expression Outcomes in Regional Brain Tissue. J Child Neurol 2021; 36:1177-1188. [PMID: 33557678 PMCID: PMC8349921 DOI: 10.1177/0883073820987742] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This study has extended previous metabolic measures in postmortem tissues (frontal and parietal lobes, pons, cerebellum, hippocampus, and cerebral cortex) obtained from a 37-year-old male patient with succinic semialdehyde dehydrogenase deficiency (SSADHD) who expired from SUDEP (sudden unexplained death in epilepsy). Histopathologic characterization of fixed cortex and hippocampus revealed mild to moderate astrogliosis, especially in white matter. Analysis of total phospholipid mass in all sections of the patient revealed a 61% increase in cortex and 51% decrease in hippocampus as compared to (n = 2-4) approximately age-matched controls. Examination of mass and molar composition of major phospholipid classes showed decreases in phospholipids enriched in myelin, such as phosphatidylserine, sphingomyelin, and ethanolamine plasmalogen. Evaluation of gene expression (RT2 Profiler PCR Arrays, GABA, glutamate; Qiagen) revealed dysregulation in 14/15 GABAA receptor subunits in cerebellum, parietal, and frontal lobes with the most significant downregulation in ∊, θ, ρ1, and ρ2 subunits (7.7-9.9-fold). GABAB receptor subunits were largely unaffected, as were ionotropic glutamate receptors. The metabotropic glutamate receptor 6 was consistently downregulated (maximum 5.9-fold) as was the neurotransmitter transporter (GABA), member 13 (maximum 7.3-fold). For other genes, consistent dysregulation was seen for interleukin 1β (maximum downregulation 9.9-fold) and synuclein α (maximal upregulation 6.5-fold). Our data provide unique insight into SSADHD brain function, confirming astrogliosis and lipid abnormalities previously observed in the null mouse model while highlighting long-term effects on GABAergic/glutamatergic gene expression in this disorder.
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Affiliation(s)
- DC Walters
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA
| | - R Lawrence
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND
| | - T Kirby
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA
| | - JT Ahrendsen
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - MP Anderson
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - J-B Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA
| | - EJ Murphy
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND
| | - KM Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA,Correspondence: Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Health Sciences Building Room 210C, Washington State University, 412 E. Spokane Falls Boulevard, Spokane, WA 99202-2131; phone 509-358-7954; fax 508-358-7667;
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6
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Pearl PL, DiBacco ML, Papadelis C, Opladen T, Hanson E, Roullet JB, Gibson KM. Succinic Semialdehyde Dehydrogenase Deficiency: Review of the Natural History Study. J Child Neurol 2021; 36:1153-1161. [PMID: 33393837 PMCID: PMC8254814 DOI: 10.1177/0883073820981262] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The SSADHD Natural History Study was initiated in 2019 to define the natural course and identify biomarkers correlating with severity. METHODS The study is conducted by 4 institutions: BCH (US clinical), WSU (bioanalytical core), USF (biostatistical core), and Heidelberg (iNTD), with support from the family advocacy group (SSADH Association). Recruitment goals were to study 20 patients on-site at BCH, 10 with iNTD, and 25 as a standard-of care cohort. RESULTS At this half-way point of this longitudinal study, 28 subjects have been recruited (57% female, mean 9 years, range 18 months-40 years). Epilepsy is present in half and increases in incidence and severity, as do psychiatric symptoms, in adolescence and adulthood. The average Full Scale IQ (FSIQ) was 53 (Verbal score of 56, Non Verbal score of 49), and half scored as having ASD. Although there was no correlation between gene variant and phenotypic severity, there were extreme cases of lowest functioning in one individual and highest in another that may have genotype-phenotype correlation. The most common EEG finding was mild background slowing with rare epileptiform activity, whereas high-density EEG and magnetoencephalography showed reduction in the gamma frequency band consistent with GABAergic dysfunction. MR spectroscopy showed elevations in the GABA/NAA ratio in all regions studied with no crossover between subjects and controls. CONCLUSIONS The SSADH Natural History Study is providing a unique opportunity to study the complex pathophysiology longitudinally and derive electrophysiologic, neuroimaging, and laboratory data for correlation and to serve as biomarkers for clinical trials and prognostic assessments in this ultra-rare inherited disorder of GABA metabolism.
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Affiliation(s)
- Phillip L Pearl
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA
| | - Melissa L DiBacco
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA
| | - Christos Papadelis
- Jane and John Justin Neuroscience Center, Cook Children’s Health Care System, 1500 Cooper Street, Fort Worth, TX 76104, USA; Department of Pediatrics, TCU and UNTHSC School of Medicine, Fort Worth, TX, USA; Laboratory of Children’s Brain Dynamics, Division of Newborn Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Thomas Opladen
- Department of Child Neurology and Metabolic Disorders, University Children’s Hospital, Heidelberg, Germany
| | - Ellen Hanson
- Neurodevelopmental Core, Boston Children’s Hospital, Harvard Medical School, Boston, MA
| | - Jean-Baptiste Roullet
- College of Pharmacy, Department of Pharmacotherapy, Washington State University, Spokane, WA
| | - K. Michael Gibson
- College of Pharmacy, Department of Pharmacotherapy, Washington State University, Spokane, WA
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7
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Mastrangelo M. Epilepsy in inherited neurotransmitter disorders: Spotlights on pathophysiology and clinical management. Metab Brain Dis 2021; 36:29-43. [PMID: 33095372 DOI: 10.1007/s11011-020-00635-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 10/16/2020] [Indexed: 01/02/2023]
Abstract
Inborn errors of neurotransmitter metabolism are ultrarare disorders affecting neurotransmitter biosynthesis, breakdown or transport or their essential cofactors. Neurotransmitter dysfunctions could also result from the impairment of neuronal receptors, intracellular signaling, vesicle release or other synaptic abnormalities. Epilepsy is the main clinical hallmark in some of these diseases (e.g. disorders of GABA metabolism, glycine encephalopathy) while it is infrequent in others (e.g. all the disorders of monoamine metabolism in exception for dihydropteridine reductase deficiency). This review analyzes the epileptogenic mechanisms, the epilepsy phenotypes and the principle for the clinical management of epilepsy in primary and secondary inherited disorders of neurotransmitter metabolism (disorders of GABA, serine and glycine metabolism, disorders of neurotransmitter receptors and secondary neurotransmitter diseases).
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Affiliation(s)
- Mario Mastrangelo
- Child Neurology and Psychiatry Unit-Department of Human Neuroscience, Sapienza Università di Roma-Umberto I Policlinico di Roma, Via dei Sabelli, 108 - 00141, Roma, Italy.
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Gavrilovici C, Rho JM. Metabolic epilepsies amenable to ketogenic therapies: Indications, contraindications, and underlying mechanisms. J Inherit Metab Dis 2021; 44:42-53. [PMID: 32654164 DOI: 10.1002/jimd.12283] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 07/04/2020] [Accepted: 07/07/2020] [Indexed: 12/20/2022]
Abstract
Metabolic epilepsies arise in the context of rare inborn errors of metabolism (IEM), notably glucose transporter type 1 deficiency syndrome, succinic semialdehyde dehydrogenase deficiency, pyruvate dehydrogenase complex deficiency, nonketotic hyperglycinemia, and mitochondrial cytopathies. A common feature of these disorders is impaired bioenergetics, which through incompletely defined mechanisms result in a wide spectrum of neurological symptoms, such as epileptic seizures, developmental delay, and movement disorders. The ketogenic diet (KD) has been successfully utilized to treat such conditions to varying degrees. While the mechanisms underlying the clinical efficacy of the KD in IEM remain unclear, it is likely that the proposed heterogeneous targets influenced by the KD work in concert to rectify or ameliorate the downstream negative consequences of genetic mutations affecting key metabolic enzymes and substrates-such as oxidative stress and cell death. These beneficial effects can be broadly grouped into restoration of impaired bioenergetics and synaptic dysfunction, improved redox homeostasis, anti-inflammatory, and epigenetic activity. Hence, it is conceivable that the KD might prove useful in other metabolic disorders that present with epileptic seizures. At the same time, however, there are notable contraindications to KD use, such as fatty acid oxidation disorders. Clearly, more research is needed to better characterize those metabolic epilepsies that would be amenable to ketogenic therapies, both experimentally and clinically. In the end, the expanded knowledge base will be critical to designing metabolism-based treatments that can afford greater clinical efficacy and tolerability compared to current KD approaches, and improved long-term outcomes for patients.
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Affiliation(s)
- Cezar Gavrilovici
- Departments of Neurosciences and Pediatrics, University of California San Diego, Rady Children's Hospital, San Diego, California, USA
| | - Jong M Rho
- Departments of Neurosciences and Pediatrics, University of California San Diego, Rady Children's Hospital, San Diego, California, USA
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9
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Abdou MM. Synopsis of recent synthetic methods and biological applications of phosphinic acid derivatives. Tetrahedron 2020. [DOI: 10.1016/j.tet.2020.131251] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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10
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Abstract
Inborn errors of metabolism, also known as inherited metabolic diseases, constitute an important group of conditions presenting with neurologic signs in newborns. They are individually rare but collectively common. Many are treatable through restoration of homeostasis of a disrupted metabolic pathway. Given their frequency and potential for treatment, the clinician should be aware of this group of conditions and learn to identify the typical manifestations of the different inborn errors of metabolism. In this review, we summarize the clinical, laboratory, electrophysiologic, and neuroimaging findings of the different inborn errors of metabolism that can present with florid neurologic signs and symptoms in the neonatal period.
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MESH Headings
- Adult
- Female
- Humans
- Infant, Newborn
- Infant, Newborn, Diseases/diagnosis
- Infant, Newborn, Diseases/diagnostic imaging
- Infant, Newborn, Diseases/physiopathology
- Infant, Newborn, Diseases/therapy
- Metabolism, Inborn Errors/diagnosis
- Metabolism, Inborn Errors/diagnostic imaging
- Metabolism, Inborn Errors/physiopathology
- Metabolism, Inborn Errors/therapy
- Neuroimaging
- Pregnancy
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Affiliation(s)
- Carlos R Ferreira
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States; Rare Disease Institute, Children's National Health System, Washington, DC, United States
| | - Clara D M van Karnebeek
- Departments of Pediatrics and Clinical Genetics, Amsterdam University Medical Centers, Amsterdam, The Netherlands; Department of Pediatrics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC, Canada.
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11
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DiBacco ML, Roullet JB, Kapur K, Brown MN, Walters DC, Gibson KM, Pearl PL. Age-related phenotype and biomarker changes in SSADH deficiency. Ann Clin Transl Neurol 2018; 6:114-120. [PMID: 30656189 PMCID: PMC6331944 DOI: 10.1002/acn3.696] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 10/11/2018] [Indexed: 12/30/2022] Open
Abstract
Objective Succinic Semialdehyde Dehydrogenase (SSADH) deficiency is a disorder of elevated gamma‐amino butyric acid (GABA) and gamma hydroxybutyric acid (GHB) and a complex neuropsychiatric profile. Adult reports suggest worsening epilepsy and high SUDEP risk. Methods Subjects with confirmed SSADH deficiency were recruited into a longitudinal study. Plasma thyroid hormone and total GABA/GHB were quantified by standard clinical chemistry methodologies and mass spectrometry, respectively. Results A total of 133 subjects with SSADH deficiency are enrolled in the registry; 49 participated in the longitudinal study. The age range of the population is 8 weeks to 63 years (median 7.75 year; 44% male). There is a significant difference in proportions among the age groups in subjects affected with hypotonia, compulsive behavior, sleep disturbances, and seizures. Epilepsy is present in 50% of the total population, and more prevalent in subjects 12 years and older (P = 0.001). The median age of onset for absence seizures was 2 years, and 12 years for generalized tonic‐clonic seizures (P < 0.01). The SUDEP rate in adults was 12% (4/33). There was a significant age‐dependent negative correlation between GABA and T3 levels. Interpretation There is an age‐dependent association with worsening of epilepsy, behavioral disturbances including obsessive‐compulsive behavior, and sleep disturbances with age in SSADH deficiency. There is a high risk of SUDEP. We have observed more absence seizures in younger patients, compared to tonic‐clonic in the older cohort, which correlates with age‐related changes in GABA and GHB concentration and thyroid function, as well as the natural history of seizures in the murine model.
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Affiliation(s)
- Melissa L DiBacco
- Department of Neurology Boston Children's Hospital Harvard Medical School Boston Massachusetts
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy College of Pharmacy and Pharmaceutical Sciences Washington State University Spokane Washington
| | - Kush Kapur
- Department of Neurology Boston Children's Hospital Harvard Medical School Boston Massachusetts
| | - Madalyn N Brown
- Department of Pharmacotherapy College of Pharmacy and Pharmaceutical Sciences Washington State University Spokane Washington
| | - Dana C Walters
- Department of Pharmacotherapy College of Pharmacy and Pharmaceutical Sciences Washington State University Spokane Washington
| | - K Michael Gibson
- Department of Pharmacotherapy College of Pharmacy and Pharmaceutical Sciences Washington State University Spokane Washington
| | - Phillip L Pearl
- Department of Neurology Boston Children's Hospital Harvard Medical School Boston Massachusetts
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Kölker S. Metabolism of amino acid neurotransmitters: the synaptic disorder underlying inherited metabolic diseases. J Inherit Metab Dis 2018; 41:1055-1063. [PMID: 29869166 DOI: 10.1007/s10545-018-0201-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/09/2018] [Accepted: 05/14/2018] [Indexed: 10/14/2022]
Abstract
Amino acids are involved in various metabolic pathways and some of them also act as neurotransmitters. Since biosynthesis of L-glutamate and γ-aminobutyric acid (GABA) requires 2-oxoglutarate while 3-phosphoglycerate is the precursor of L-glycine and D-serine, evolutionary selection of these amino acid neurotransmitters might have been driven by their capacity to provide important information about the glycolytic pathway and Krebs cycle. Synthesis and recycling of amino acid neurotransmitters as well as composition and function of their receptors are often compromised in inherited metabolic diseases. For instance, increased plasma L-phenylalanine concentrations impair cerebral biosynthesis of protein and bioamines in phenylketonuria, while elevated cerebral L-phenylalanine directly acts via ionotropic glutamate receptors. In succinic semialdehyde dehydrogenase deficiency, the neurotransmitter GABA and neuromodulatory γ-hydroxybutyric acid are elevated. Chronic hyperGABAergic state results in progressive downregulation of GABAA and GABAB receptors and impaired mitophagy. In glycine encephalopathy, the neurological phenotype is precipitated by L-glycine acting both via cortical NMDA receptors and glycine receptors in spinal cord and brain stem neurons. Serine deficiency syndromes are biochemically characterized by decreased biosynthesis of L-serine, an important neurotrophic factor, and the neurotransmitters D-serine and L-glycine. Supplementation with L-serine and L-glycine has a positive effect on seizure frequency and spasticity, while neurocognitive development can only be improved if treatment starts in utero or immediately postnatally. With novel techniques, the study of synaptic dysfunction in inherited metabolic diseases has become an emerging research field. More and better therapies are needed for these difficult-to-treat diseases.
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Affiliation(s)
- Stefan Kölker
- Division of Pediatric Neurology and Metabolic Medicine, Centre for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany.
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Vogel KR, Ainslie GR, Walters DC, McConnell A, Dhamne SC, Rotenberg A, Roullet JB, Gibson KM. Succinic semialdehyde dehydrogenase deficiency, a disorder of GABA metabolism: an update on pharmacological and enzyme-replacement therapeutic strategies. J Inherit Metab Dis 2018; 41:699-708. [PMID: 29460030 PMCID: PMC6041169 DOI: 10.1007/s10545-018-0153-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/29/2018] [Accepted: 01/31/2018] [Indexed: 12/16/2022]
Abstract
We present an update to the status of research on succinic semialdehyde dehydrogenase (SSADH) deficiency (SSADHD), a rare disorder of GABA metabolism. This is an unusual disorder featuring the accumulation of both GABA and its neuromodulatory analog, gamma-hydroxybutyric acid (GHB), and recent studies have advanced the potential clinical application of NCS-382, a putative GHB receptor antagonist. Animal studies have provided proof-of-concept that enzyme replacement therapy could represent a long-term therapeutic option. The characterization of neuronal stem cells (NSCs) derived from aldehyde dehydrogenase 5a1-/- (aldh5a1-/-) mice, the murine model of SSADHD, has highlighted NSC utility as an in vitro system in which to study therapeutics and associated toxicological properties. Gene expression analyses have revealed that transcripts encoding GABAA receptors are down-regulated and may remain largely immature in aldh5a1-/- brain, characterized by excitatory as opposed to inhibitory outputs, the latter being the expected action in the mature central nervous system. This indicates that agents altering chloride channel activity may be therapeutically relevant in SSADHD. The most recent therapeutic prospects include mTOR (mechanistic target of rapamycin) inhibitors, drugs that have received attention with the elucidation of the effects of elevated GABA on autophagy. The outlook for novel therapeutic trials in SSADHD continues to improve.
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Affiliation(s)
- Kara R Vogel
- Department of Neuroscience, University of Wisconsin, Madison, WI, USA
| | | | - Dana C Walters
- Department of Pharmacotherapy, College of Pharmacy, Washington State University, 412 E. Spokane Falls Blvd, Health Sciences Building Room 210, Spokane, WA, 99204, USA
| | | | - Sameer C Dhamne
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Alexander Rotenberg
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy, Washington State University, 412 E. Spokane Falls Blvd, Health Sciences Building Room 210, Spokane, WA, 99204, USA
| | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy, Washington State University, 412 E. Spokane Falls Blvd, Health Sciences Building Room 210, Spokane, WA, 99204, USA.
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Benke D, Möhler H. Impact on GABA systems in monogenetic developmental CNS disorders: Clues to symptomatic treatment. Neuropharmacology 2017; 136:46-55. [PMID: 28764992 DOI: 10.1016/j.neuropharm.2017.07.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 07/26/2017] [Accepted: 07/28/2017] [Indexed: 12/26/2022]
Abstract
Animal studies of several single-gene disorders demonstrate that reversing the molecular signaling deficits can result in substantial symptomatic improvements in function. Focusing on the ratio of excitation to inhibition as a potential pathophysiological hallmark, seven single-gene developmental CNS disorders are reviewed which are characterized by a striking dysregulation of neuronal inhibition. Deficits in inhibition and excessive inhibition are found. The examples of developmental disorders encompass Neurofibromatosis type 1, Fragile X syndrome, Rett syndrome, Dravet syndrome including autism-like behavior, NONO-mutation-induced intellectual disability, Succinic semialdehyde dehydrogenase deficiency and Congenital nystagmus due to FRMD7 mutations. The phenotype/genotype correlations observed in animal models point to potential treatment options and will continue to inspire clinical research. Three drugs are presently in clinical trials: acamprosate and ganoxolon for Fragile X syndrome and SGS-742 for SSADH deficiency. This article is part of the "Special Issue Dedicated to Norman G. Bowery".
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Affiliation(s)
- Dietmar Benke
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Neuroscience Center Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Drug Discovery Network Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland.
| | - Hanns Möhler
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Neuroscience Center Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland; Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH), Vladimir-Prelog-Weg 10, 8023 Zurich, Switzerland.
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Vogel KR, Ainslie GR, Gibson KM. mTOR inhibitors rescue premature lethality and attenuate dysregulation of GABAergic/glutamatergic transcription in murine succinate semialdehyde dehydrogenase deficiency (SSADHD), a disorder of GABA metabolism. J Inherit Metab Dis 2016; 39:877-886. [PMID: 27518770 PMCID: PMC5114712 DOI: 10.1007/s10545-016-9959-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 06/15/2016] [Accepted: 06/21/2016] [Indexed: 02/07/2023]
Abstract
Recent studies have identified a role for supraphysiological gamma-aminobutyric acid (GABA) in the regulation of mechanistic target of rapamycin (mTOR), a protein kinase with pleiotropic roles in cellular development and homeostasis, including integration of growth factors and nutrient sensing and synaptic input in neurons (Lakhani et al. 2014; Vogel et al. 2015). Aldehyde dehydrogenase 5a1-deficient (aldh5a1 -/- ) mice, the murine orthologue of human succinic semialdehyde dehydrogenase deficiency (SSADHD), manifest increased GABA that disrupts mitophagy and increases mitochondria number with enhanced oxidant stress. Treatment with the mTOR inhibitor, rapamycin, significantly attenuates these GABA-related anomalies. We extend those studies through characterization of additional rapamycin analog (rapalog) agents including temsirolimus, dual mTOR inhibitors [Torin 1 and 2 (Tor 1/ Tor 2), Ku-0063794, and XL-765], as well as mTOR-independent autophagy inducers [trehalose, tat-Beclin 1, tacrolimus (FK-506), and NF-449) in aldh5a1 -/- mice. Rapamycin, Tor 1, and Tor 2 rescued these mice from premature lethality associated with status epilepticus. XL-765 extended lifespan significantly and induced weight gain in aldh5a1 -/- mice; untreated aldh5a1 -/- mice failed to increase body mass. Expression profiling of animals rescued with Tor 1/Tor 2 and XL-765 revealed multiple instances of pharmacological compensation and/or correction of GABAergic and glutamatergic receptors, GABA/glutamate transporters, and GABA/glutamate-associated proteins, with Tor 2 and XL-765 showing optimal outcomes. Our studies lay the groundwork for further evaluation of mTOR inhibitors in aldh5a1 -/- mice, with therapeutic ramifications for heritable disorders of GABA and glutamate neurotransmission.
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Affiliation(s)
- Kara R Vogel
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Pharmaceutical and Basic Sciences Building Room 347, 412 E. Spokane Falls Blvd, Spokane, WA, 99202, USA.
| | - Garrett R Ainslie
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Pharmaceutical and Basic Sciences Building Room 347, 412 E. Spokane Falls Blvd, Spokane, WA, 99202, USA
| | - K Michael Gibson
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Pharmaceutical and Basic Sciences Building Room 347, 412 E. Spokane Falls Blvd, Spokane, WA, 99202, USA
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Schreiber JM, Pearl PL, Dustin I, Wiggs E, Barrios E, Wassermann EM, Gibson KM, Theodore WH. Biomarkers in a Taurine Trial for Succinic Semialdehyde Dehydrogenase Deficiency. JIMD Rep 2016; 30:81-87. [PMID: 27338723 DOI: 10.1007/8904_2015_524] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 11/10/2015] [Accepted: 11/26/2015] [Indexed: 02/17/2023] Open
Abstract
AIM We tested the hypothesis that patients with succinic semialdehyde dehydrogenase (SSADH) deficiency on taurine would have decreased cortical excitability as measured by transcranial magnetic stimulation (TMS) and improved cognition, due to taurine's partial GABA(A and B) receptor agonist effects and rescue in the null mouse model from status epilepticus and premature lethality. METHOD Biomarkers including neuropsychological testing, TMS, and CSF metabolites were studied in a cohort of patients on and off three months' taurine treatment. RESULTS Seven patients (5M/2F; age range 12-33 years) were enrolled in this open-label crossover study. Baseline average full-scale IQ (FSIQ) was 44.1 (range 34-55). Of six who returned at 6-month follow-up, five completed cognitive testing (3M/2F) on therapy; average FSIQ = 43.4 (range 33-51). CSF biomarkers (n = 4 subjects) revealed elevation in taurine levels but no change in free or total GABA. Baseline cortical excitability measured with TMS agreed with previous findings in this population, with a short cortical silent period and lack of long-interval intracortical inhibition. Patients on taurine showed a decrease in cortical silent period and short-interval intracortical inhibition compared to their off taurine study. INTERPRETATION TMS demonstrated decreased inhibition in patients on taurine, in contrast to the study hypothesis, but consistent with its failure to produce clinical or cognitive improvement. TMS may be a useful biomarker for therapy in pediatric neurotransmitter disorders.
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Affiliation(s)
| | - Phillip L Pearl
- Department of Child Neurology, Children's National Medical Center (CNMC), Washington, DC, USA
| | | | | | - Emily Barrios
- Department of Child Neurology, Children's National Medical Center (CNMC), Washington, DC, USA
| | | | - K Michael Gibson
- Experimental and Systems Pharmacology, Washington State University (WSU), Spokane, WA, USA
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Malaspina P, Roullet JB, Pearl PL, Ainslie GR, Vogel KR, Gibson KM. Succinic semialdehyde dehydrogenase deficiency (SSADHD): Pathophysiological complexity and multifactorial trait associations in a rare monogenic disorder of GABA metabolism. Neurochem Int 2016; 99:72-84. [PMID: 27311541 DOI: 10.1016/j.neuint.2016.06.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 06/09/2016] [Accepted: 06/10/2016] [Indexed: 12/21/2022]
Abstract
Discovered some 35 years ago, succinic semialdehyde dehydrogenase deficiency (SSADHD) represents a rare, autosomal recessively-inherited defect in the second step of the GABA degradative pathway. Some 200 patients have been reported, with broad phenotypic and genotypic heterogeneity. SSADHD represents an unusual neurometabolic disorder in which two neuromodulatory agents, GABA (and the GABA analogue, 4-hydroxybutyrate), accumulate to supraphysiological levels. The unexpected occurrence of epilepsy in several patients is counterintuitive in view of the hyperGABAergic state, in which sedation might be expected. However, the epileptic status of some patients is most likely represented by broader imbalances of GABAergic and glutamatergic neurotransmission. Cumulative research encompassing decades of basic and clinical study of SSADHD reveal a monogenic disease with broad pathophysiological and clinical phenotypes. Numerous metabolic perturbations unmasked in SSADHD include alterations in oxidative stress parameters, dysregulation of autophagy and mitophagy, dysregulation of both inhibitory and excitatory neurotransmitters and gene expression, and unique subsets of SNP alterations of the SSADH gene (so-called ALDH5A1, or aldehyde dehydrogenase 5A1 gene) on the 6p22 chromosomal arm. While seemingly difficult to collate and interpret, these anomalies have continued to open novel pathways for pharmacotherapeutic considerations. Here, we present an update on selected aspects of SSADHD, the ALDH5A1 gene, and future avenues for research on this rare disorder of GABA metabolism.
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Affiliation(s)
- P Malaspina
- Department of Biology, University "Tor Vergata", Rome, Italy
| | - J-B Roullet
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA
| | - P L Pearl
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - G R Ainslie
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA
| | - K R Vogel
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA
| | - K M Gibson
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA.
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Parviz M, Vogel K, Gibson KM, Pearl PL. Disorders of GABA metabolism: SSADH and GABA-transaminase deficiencies. JOURNAL OF PEDIATRIC EPILEPSY 2015; 3:217-227. [PMID: 25485164 DOI: 10.3233/pep-14097] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Clinical disorders known to affect inherited gamma-amino butyric acid (GABA) metabolism are autosomal recessively inherited succinic semialdehyde dehydrogenase and GABA-transaminase deficiency. The clinical presentation of succinic semialdehyde dehydrogenase deficiency includes intellectual disability, ataxia, obsessive-compulsive disorder and epilepsy with a nonprogressive course in typical cases, although a progressive form in early childhood as well as deterioration in adulthood with worsening epilepsy are reported. GABA-transaminase deficiency is associated with a severe neonatal-infantile epileptic encephalopathy.
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Affiliation(s)
- Mahsa Parviz
- Harvard Medical School and Boston Children's Hospital, Boston, Massachusetts, USA
| | - Kara Vogel
- Biological Pharmacology, Washington State University, Pullman, Washington, USA
| | - K Michael Gibson
- Biological Pharmacology, Washington State University, Pullman, Washington, USA
| | - Phillip L Pearl
- Harvard Medical School and Boston Children's Hospital, Boston, Massachusetts, USA
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Pearl PL, Parviz M, Vogel K, Schreiber J, Theodore WH, Gibson KM. Inherited disorders of gamma-aminobutyric acid metabolism and advances in ALDH5A1 mutation identification. Dev Med Child Neurol 2015; 57:611-617. [PMID: 25558043 PMCID: PMC4485983 DOI: 10.1111/dmcn.12668] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/30/2014] [Indexed: 02/01/2023]
Abstract
Inherited disorders of gamma-aminobutyric acid (GABA) metabolism include succinic semialdehyde dehydrogenase (SSADH) and gamma-aminobutyric acid transaminase (GABA-T) deficiencies. The clinical features, pathophysiology, diagnosis, and management of both, and an updated list of mutations in the ALDH5A1 gene, which cause SSADH deficiency, are discussed. A database of 112 individuals (71 children and adolescents, and 41 adults) indicates that developmental delay and hypotonia are the most common symptoms arising from SSADH deficiency. Furthermore, epilepsy is present in two-thirds of SSADH-deficient individuals by adulthood. Research with murine genetic models and human participants, using [11 C] flumazenil positron emission tomography (FMZ-PET) and transcranial magnetic stimulation, have led to therapeutic trials, and the identification of additional disruptions to GABA metabolism. Suggestions for new therapies have arisen from findings of GABAergic effects on autophagy, with enhanced activation of the mammalian target of rapamycin (mTOR) pathway. Details of known pathogenic mutations in the ALDH5A1 gene, three of which have not previously been reported, are summarized here. Investigations into disorders of GABA metabolism provide fundamental insights into the mechanisms underlying epilepsy, and support the importance of developing biomarkers and clinical trials. Comprehensive definition of phenotypes arising as a result of deficiencies in both SSADH and GABA-T may increase our understanding of the neurophysiological consequences of a hyper-GABAergic state.
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Affiliation(s)
- Phillip L. Pearl
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston MA
| | - Mahsa Parviz
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston MA
| | - Kara Vogel
- Department of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane WA
| | - John Schreiber
- Department of Neurology, Children’s National Medical Center, Washington, DC
| | | | - K. Michael Gibson
- Department of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane WA
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Püttmann L, Stehr H, Garshasbi M, Hu H, Kahrizi K, Lipkowitz B, Jamali P, Tzschach A, Najmabadi H, Ropers HH, Musante L, Kuss AW. A novelALDH5A1mutation is associated with succinic semialdehyde dehydrogenase deficiency and severe intellectual disability in an Iranian family. Am J Med Genet A 2013; 161A:1915-22. [DOI: 10.1002/ajmg.a.36030] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 04/15/2013] [Indexed: 01/20/2023]
Affiliation(s)
| | - Henning Stehr
- Department of Vertebrate Genomics; Max Planck Institute for Molecular Genetics; Berlin; Germany
| | - Masoud Garshasbi
- Department of Human Molecular Genetics; Max Planck Institute for Molecular Genetics; Berlin; Germany
| | - Hao Hu
- Department of Human Molecular Genetics; Max Planck Institute for Molecular Genetics; Berlin; Germany
| | - Kimia Kahrizi
- Genetics Research Center; University of Social Welfare and Rehabilitation Sciences; Tehran; Iran
| | - Bettina Lipkowitz
- Department of Human Molecular Genetics; Max Planck Institute for Molecular Genetics; Berlin; Germany
| | | | - Andreas Tzschach
- Department of Human Molecular Genetics; Max Planck Institute for Molecular Genetics; Berlin; Germany
| | - Hossein Najmabadi
- Genetics Research Center; University of Social Welfare and Rehabilitation Sciences; Tehran; Iran
| | - Hans-Hilger Ropers
- Department of Human Molecular Genetics; Max Planck Institute for Molecular Genetics; Berlin; Germany
| | - Luciana Musante
- Department of Human Molecular Genetics; Max Planck Institute for Molecular Genetics; Berlin; Germany
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Vogel KR, Pearl PL, Theodore WH, McCarter RC, Jakobs C, Gibson KM. Thirty years beyond discovery--clinical trials in succinic semialdehyde dehydrogenase deficiency, a disorder of GABA metabolism. J Inherit Metab Dis 2013; 36:401-10. [PMID: 22739941 PMCID: PMC4349389 DOI: 10.1007/s10545-012-9499-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 05/09/2012] [Accepted: 05/14/2012] [Indexed: 10/28/2022]
Abstract
This review summarizes a presentation made at the retirement Symposium of Prof. Dr. Cornelis Jakobs in November of 2011, highlighting the progress toward clinical trials in succinic semialdehyde dehydrogenase (SSADH) deficiency, a disorder first recognized in 1981. Active and potential clinical interventions, including vigabatrin, L-cycloserine, the GHB receptor antagonist NCS-382, and the ketogenic diet, are discussed. Several biomarkers to gauge clinical efficacy have been identified, including cerebrospinal fluid metabolites, neuropsychiatric testing, MRI, EEG, and measures of GABAergic function including (11 C)flumazenil positron emission tomography (PET) and transcranial magnetic stimulation (TMS). Thirty years after its discovery, encompassing extensive studies in both patients and the corresponding murine model, we are now running an open-label trial of taurine intervention, and are poised to undertake a phase II trial of the GABAB receptor antagonist SGS742.
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Affiliation(s)
- Kara R Vogel
- Section of Clinical Pharmacology, College of Pharmacy, Washington State University, Spokane, WA 99202-2131, USA.
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Vanadia E, Gibson KM, Pearl PL, Trapolino E, Mangano S, Vanadia F. Therapeutic efficacy of magnesium valproate in succinic semialdehyde dehydrogenase deficiency. JIMD Rep 2012; 8:133-7. [PMID: 23430529 DOI: 10.1007/8904_2012_170] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Revised: 07/18/2012] [Accepted: 07/24/2012] [Indexed: 12/26/2022] Open
Abstract
Succinic semialdehyde dehydrogenase deficiency (SSADHD), a disorder of γ-aminobutyric acid (GABA) metabolism, manifests typically as a nonprogressive neurodevelopmental disorder with cognitive deficiency, neuropsychiatric morbidity and epilepsy. Therapy targets symptomatic seizures and neurobehavioral disturbances. We report an adolescent female with SSADHD whose unresponsiveness to a broad spectrum of antiepileptics was circumvented with magnesium valproate (MgVPA). Epilepsy remains well controlled in our patient, with concomitant improvements in behavioral symptoms and an absence of adverse symptoms. MgVPA intervention may have utility in SSADHD.
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Affiliation(s)
- Elena Vanadia
- Department of Child and Adolescent Neuropsychiatry, University of Palermo, Palermo, Italy,
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Reis J, Cohen LG, Pearl PL, Fritsch B, Jung NH, Dustin I, Theodore WH. GABAB-ergic motor cortex dysfunction in SSADH deficiency. Neurology 2012; 79:47-54. [PMID: 22722631 DOI: 10.1212/wnl.0b013e31825dcf71] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Succinic semialdehyde dehydrogenase (SSADH) deficiency is a rare autosomal recessive disorder of GABA degradation leading to elevations in brain GABA and γ-hydroxybutyric acid (GHB). The effect of chronically elevated GABA and GHB on cortical excitability is unknown. We hypothesized that use-dependent downregulation of GABA receptor expression would promote cortical disinhibition rather than inhibition, predominantly via presynaptic GABAergic mechanisms. METHODS We quantified the magnitude of excitation and inhibition in primary motor cortex (M1) in patients with SSADH deficiency, their parents (obligate heterozygotes), age-matched healthy young controls, and healthy adults using single and paired pulse transcranial magnetic stimulation (TMS). RESULTS Long interval intracortical inhibition was significantly reduced and the cortical silent period was significantly shortened in patients with SSADH deficiency compared to heterozygous parents and control groups. CONCLUSIONS Since long interval intracortical inhibition and cortical silent period are thought to reflect GABA(B) receptor-mediated inhibitory circuits, our results point to a particularly GABA(B)-ergic motor cortex dysfunction in patients with SSADH deficiency. This human phenotype is consistent with the proposed mechanism of use-dependent downregulation of postsynaptic GABA(B) receptors in SSADH deficiency animal models. Additionally, the results suggest autoinhibition of GABAergic neurons. This first demonstration of altered GABA(B)-ergic function in patients with SSADH deficiency may help to explain clinical features of the disease, and suggest pathophysiologic mechanisms in other neurotransmitter-related disorders.
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Affiliation(s)
- Janine Reis
- Human Cortical Physiology and Stroke Neurorehabilitation Section, NINDS, NIH, Bethesda, MD, USA.
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Pearl PL, Shukla L, Theodore WH, Jakobs C, Gibson KM. Epilepsy in succinic semialdehyde dehydrogenase deficiency, a disorder of GABA metabolism. Brain Dev 2011; 33:796-805. [PMID: 21664777 PMCID: PMC4385391 DOI: 10.1016/j.braindev.2011.04.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 04/27/2011] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Succinic semialdehyde dehydrogenase (SSADH) deficiency is a gamma-aminobutyric acid (GABA) degradative defect. Epilepsy affects half of patients. The murine model is associated with a transition from absence to convulsive seizures in the third week, with fatal status epilepticus. METHODS The clinical phenotype is reported from a patient database. Flumazenil-Positron Emission Topography (FMZ-PET) and Transcranial Magnetic Stimulation (TMS) were used to study GABA neurotransmission. Electrocorticography, single cell electrophysiology, and radioligand binding studies are reported from animal studies. RESULTS Generalized seizures predominate, including tonic-clonic, atypical absence, and myoclonic. EEG discharges are typically generalized spike-wave. MRI shows a dentatopallidoluysian pattern. Sudden Unexpected Death in Epilepsy Patients (SUDEP) has occurred and the associated neuropathology reveals chronic excitotoxic injury in gloubus pallidus. Investigations using FMZ-PET and TMS support downregulation of GABA(A) and GABA(B) activity, respectively, in patients. Gamma-hydroxybutyrate (GHB) induces spike-wave discharges in homozygous null mice via GHB and GABA(B)-mediated mechanisms. These resemble absence seizures and are abolished by a GABA(B) receptor antagonist. Decreased binding of GABA(A) and GABA(B) receptor antagonists has been demonstrated in P19 and P14 null mice, respectively. Downregulation of GABA(A) and GABA(B) receptor subunits is observed by P14. GABA(A) and GABA(B) mediated potentials are reduced from P8-P14. CONCLUSION Generalized epilepsy and epileptiform discharges are characteristic of SSADH deficiency. Spontaneous absence seizures appear in null mice by the third week, which may be induced by GHB or GABA(B) activity. Subsequent overuse dependent downregulation of GABA(A) and GABA(B) receptor activity may be associated with hyperexcitability concomitant with the transition to generalized seizures.
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Affiliation(s)
- Phillip L. Pearl
- Department of Neurology, Children’s National Medical Center, George Washington University School of Medicine, Washington, D.C., USA,Clinical Epilepsy Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Lovy Shukla
- Department of Neurology, Children’s National Medical Center, George Washington University School of Medicine, Washington, D.C., USA
| | - William H. Theodore
- Clinical Epilepsy Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Cornelis Jakobs
- Metabolic Unit, Department of Clinical Chemistry, Vrije University Medical Center, Amsterdam, The Netherlands
| | - K. Michael Gibson
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
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Kim KJ, Pearl PL, Jensen K, Snead OC, Malaspina P, Jakobs C, Gibson KM. Succinic semialdehyde dehydrogenase: biochemical-molecular-clinical disease mechanisms, redox regulation, and functional significance. Antioxid Redox Signal 2011; 15:691-718. [PMID: 20973619 PMCID: PMC3125545 DOI: 10.1089/ars.2010.3470] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH; aldehyde dehydrogenase 5a1, ALDH5A1; E.C. 1.2.1.24; OMIM 610045, 271980) deficiency is a rare heritable disorder that disrupts the metabolism of the inhibitory neurotransmitter 4-aminobutyric acid (GABA). Identified in conjunction with increased urinary excretion of the GABA analog gamma-hydroxybutyric acid (GHB), numerous patients have been identified worldwide and the autosomal-recessive disorder has been modeled in mice. The phenotype is one of nonprogressive neurological dysfunction in which seizures may be prominently displayed. The murine model is a reasonable phenocopy of the human disorder, yet the severity of the seizure disorder in the mouse exceeds that observed in SSADH-deficient patients. Abnormalities in GABAergic and GHBergic neurotransmission, documented in patients and mice, form a component of disease pathophysiology, although numerous other disturbances (metabolite accumulations, myelin abnormalities, oxidant stress, neurosteroid depletion, altered bioenergetics, etc.) are also likely to be involved in developing the disease phenotype. Most recently, the demonstration of a redox control system in the SSADH protein active site has provided new insights into the regulation of SSADH by the cellular oxidation/reduction potential. The current review summarizes some 30 years of research on this protein and disease, addressing pathological mechanisms in human and mouse at the protein, metabolic, molecular, and whole-animal level.
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Affiliation(s)
- Kyung-Jin Kim
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Phillip L. Pearl
- Department of Neurology, Children's National Medical Center, Washington, District of Columbia
| | - Kimmo Jensen
- Synaptic Physiology Laboratory, Department of Physiology and Biophysics, Aarhus University, Aarhus, Denmark
- Center for Psychiatric Research, Aarhus University Hospital, Risskov, Denmark
| | - O. Carter Snead
- Department of Neurology, Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | | | - Cornelis Jakobs
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - K. Michael Gibson
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan
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Errington AC, Gibson KM, Crunelli V, Cope DW. Aberrant GABA(A) receptor-mediated inhibition in cortico-thalamic networks of succinic semialdehyde dehydrogenase deficient mice. PLoS One 2011; 6:e19021. [PMID: 21526163 PMCID: PMC3079762 DOI: 10.1371/journal.pone.0019021] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 03/14/2011] [Indexed: 01/19/2023] Open
Abstract
Aberrant γ-aminobutyric acid type A (GABAA) receptor-mediated inhibition in cortico-thalamic networks remains an attractive mechanism for typical absence seizure genesis. Using the whole-cell patch clamp technique we examined ‘phasic’ and ‘tonic’ GABAA inhibition in thalamocortical neurons of somatosensory (ventrobasal, VB) thalamus, nucleus reticularis thalami (NRT) neurons, and layer 5/6 pyramidal neurons of the somatosensory (barrel) cortex of succinic semialdehyde dehydrogenase (SSADH) knock-out (SSADH−/−) mice that replicate human SSADH deficiency and exhibit typical absence seizures. We found increased sIPSC frequency in both VB and NRT neurons and larger sIPSC amplitude in VB neurons of SSADH−/− mice compared to wild-type animals, demonstrating an increase in total phasic inhibition in thalamus of SSADH−/− mice. mIPSCs in both VB and NRT neurons were no different between genotypes, although there remained a trend toward more events in SSADH−/− mice. In cortical layer 5/6 pyramidal neurons, sIPSCs were fewer but larger in SSADH−/− mice, a feature retained by mIPSCs. Tonic currents were larger in both thalamocortical neurons and layer 5/6 pyramidal neurons from SSADH−/− mice compared to WTs. These data show that enhanced, rather than compromised, GABAA receptor-mediated inhibition occurs in cortico-thalamic networks of SSADH−/− mice. In agreement with previous studies, GABAA receptor-mediated inhibitory gain-of-function may be a common feature in models of typical absence seizures, and could be of pathological importance in patients with SSADH deficiency.
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Affiliation(s)
- Adam C Errington
- School of Biosciences, Cardiff University, Cardiff, United Kingdom.
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Expression of GABAergic receptors in mouse taste receptor cells. PLoS One 2010; 5:e13639. [PMID: 21049022 PMCID: PMC2964312 DOI: 10.1371/journal.pone.0013639] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 10/04/2010] [Indexed: 12/05/2022] Open
Abstract
Background Multiple excitatory neurotransmitters have been identified in the mammalian taste transduction, with few studies focused on inhibitory neurotransmitters. Since the synthetic enzyme glutamate decarboxylase (GAD) for gamma-aminobutyric acid (GABA) is expressed in a subset of mouse taste cells, we hypothesized that other components of the GABA signaling pathway are likely expressed in this system. GABA signaling is initiated by the activation of either ionotropic receptors (GABAA and GABAC) or metabotropic receptors (GABAB) while it is terminated by the re-uptake of GABA through transporters (GATs). Methodology/Principal Findings Using reverse transcriptase-PCR (RT-PCR) analysis, we investigated the expression of different GABA signaling molecules in the mouse taste system. Taste receptor cells (TRCs) in the circumvallate papillae express multiple subunits of the GABAA and GABAB receptors as well as multiple GATs. Immunocytochemical analyses examined the distribution of the GABA machinery in the circumvallate papillae. Both GABAA-and GABAB- immunoreactivity were detected in the peripheral taste receptor cells. We also used transgenic mice that express green fluorescent protein (GFP) in either the Type II taste cells, which can respond to bitter, sweet or umami taste stimuli, or in the Type III GAD67 expressing taste cells. Thus, we were able to identify that GABAergic receptors are expressed in some Type II and Type III taste cells. Mouse GAT4 labeling was concentrated in the cells surrounding the taste buds with a few positively labeled TRCs at the margins of the taste buds. Conclusions/Significance The presence of GABAergic receptors localized on Type II and Type III taste cells suggests that GABA is likely modulating evoked taste responses in the mouse taste bud.
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Dósa Z, Nieto-Gonzalez JL, Korshoej AR, Gibson KM, Jensen K. Effect of gene dosage on single-cell hippocampal electrophysiology in a murine model of SSADH deficiency (gamma-hydroxybutyric aciduria). Epilepsy Res 2010; 90:39-46. [PMID: 20363598 DOI: 10.1016/j.eplepsyres.2010.03.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 03/02/2010] [Accepted: 03/07/2010] [Indexed: 12/20/2022]
Abstract
Human and murine succinic semialdehyde dehydrogenase (SSADH; gamma-hydroxybutyric (GHB) aciduria) deficiency represents an epileptic disorder associated with hyperGABA- and hyperGHB-ergic states. Despite significant neurotransmitters alterations, well-defined single-cell electrophysiological studies, aimed to provide insight into regional neuropathology, have been lacking. In this study, we characterized the effect of residual SSADH enzyme function/increased GABA levels on single-cell hippocampal electrophysiology in SSADH+/+ (wild-type; WT), SSADH+/- (heterozygous; HET), and SSADH-/- (knock-out; KO) mice. Tonic extrasynaptic GABAA receptor (GABAAR)-mediated currents were elevated in HET and KO mice, whereas phasic synaptic GABAAR currents were unaltered in dentate gyrus granule cells. Similarly, tonic GABAAR-mediated currents were increased in dentate gyrus interneurons of KO animals, while phasic GABAergic neurotransmission was unaffected in the same cells. Our results indicate global disruption of cortical networks in SSADH KO mice, affecting both excitatory and inhibitory neurons. Our findings provide new clues concerning seizure evolution in the murine model (absence-->tonic-clonic-->status epilepticus), and extend pathophysiological insight into human SSADH deficiency.
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Affiliation(s)
- Zita Dósa
- Synaptic Physiology Laboratory, Department of Physiology and Biophysics, Aarhus University, Aarhus, Denmark
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Tsuji M, Aida N, Obata T, Tomiyasu M, Furuya N, Kurosawa K, Errami A, Gibson KM, Salomons GS, Jakobs C, Osaka H. A new case of GABA transaminase deficiency facilitated by proton MR spectroscopy. J Inherit Metab Dis 2010; 33:85-90. [PMID: 20052547 PMCID: PMC2828554 DOI: 10.1007/s10545-009-9022-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 10/29/2009] [Accepted: 11/23/2009] [Indexed: 11/20/2022]
Abstract
BACKGROUND Deficiency of 4-aminobutyrate aminotransferase (GABA-T) is a rare disorder of GABA catabolism, with only a single sibship reported. We report on a third case, a Japanese female infant with severe psychomotor retardation and recurrent episodic lethargy with intractable seizures, with the diagnosis facilitated by proton magnetic resonance (MR) spectroscopy ((1)H-MRS). METHODS Neuroimaging was performed at the first episode of lethargy. For (1)H-MRS, locations were placed in the semioval center and the basal ganglia. Quantification of metabolite concentrations were derived using the LCModel. We confirmed the diagnosis subsequently by enzyme and molecular studies, which involved direct DNA sequence analysis and the development of a novel multiplex ligation-dependent probe amplification test. RESULTS (1)H-MRS analysis revealed an elevated GABA concentration in the basal ganglia (2.9 mmol/l). Based on the results of quantitative (1)H-MRS and clinical findings, GABA-T deficiency was suspected and confirmed in cultured lymphoblasts. Molecular studies of the GABA-T gene revealed compound heterozygosity for a deletion of one exon and a missense mutation, 275G>A, which was not detected in 210 control chromosomes. CONCLUSIONS Our results suggest that excessive prenatal GABA exposure in the central nervous system (CNS) was responsible for the clinical manifestations of GABA transaminase deficiency. Our findings suggest the dual nature of GABA as an excitatory molecule early in life, followed by a functional switch to an inhibitory species later in development. Furthermore, quantitative (1)H-MRS appears to be a useful, noninvasive tool for detecting inborn errors of GABA metabolism in the CNS.
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Affiliation(s)
- Megumi Tsuji
- Division of Neurology, Clinical Research Institute, Kanagawa Children’s Medical Center, 2-138-4 Mutsukawa, Minami-ku, Yokohama, 232-8555 Japan
| | - Noriko Aida
- Division of Radiology, Clinical Research Institute, Kanagawa Children’s Medical Center, 2-138-4 Mutsukawa, Minami-ku, Yokohama, 232-8555 Japan
| | - Takayuki Obata
- Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Moyoko Tomiyasu
- Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan
| | - Noritaka Furuya
- Division of Genetics, Clinical Research Institute, Kanagawa Children’s Medical Center, 2-138-4 Mutsukawa, Minami-ku, Yokohama, 232-8555 Japan
| | - Kenji Kurosawa
- Division of Genetics, Clinical Research Institute, Kanagawa Children’s Medical Center, 2-138-4 Mutsukawa, Minami-ku, Yokohama, 232-8555 Japan
| | | | - K. Michael Gibson
- Department of Biological Sciences, Michigan Technological University, Houghton, MI USA
| | - Gajja S. Salomons
- Metabolic Unit, Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Cornelis Jakobs
- Metabolic Unit, Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Hitoshi Osaka
- Division of Neurology, Clinical Research Institute, Kanagawa Children’s Medical Center, 2-138-4 Mutsukawa, Minami-ku, Yokohama, 232-8555 Japan
- Molecular Pathology & Genetics Division, Kanagawa Cancer Center Research Institute, Yokohama, Japan
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Di Rosa G, Malaspina P, Blasi P, Dionisi-Vici C, Rizzo C, Tortorella G, Crutchfield SR, Gibson KM. Visual evoked potentials in succinate semialdehyde dehydrogenase (SSADH) deficiency. J Inherit Metab Dis 2009; 32 Suppl 1:S201-5. [PMID: 19484191 PMCID: PMC2888988 DOI: 10.1007/s10545-009-1154-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 04/17/2009] [Accepted: 04/23/2009] [Indexed: 10/20/2022]
Abstract
In mammals, increased GABA in the central nervous system has been associated with abnormalities of visual evoked potentials (VEPs), predominantly manifested as increased latency of the major positive component P100. Accordingly, we hypothesized that patients with a defect in GABA metabolism, succinate semialdehyde dehydrogenase (SSADH) deficiency (in whom supraphysiological levels of GABA accumulate), would manifest VEP anomalies. We evaluated VEPs on two patients with confirmed SSADH deficiency. Whereas the P100 latencies and amplitudes for binocular VEP analyses were within normal ranges for both patients, the P100 latencies were markedly delayed for left eye (OS) (and right eye (OD), patient 1) and monocular OS (patient 2): 134-147 ms; normal <118 ms. We hypothesize that elevated GABA in ocular tissue of SSADH patients leads to a use-dependent downregulation of the major GABAergic receptor in eye, GABA(C), and that the VEP recordings' abnormalities, as evidenced by P100 latency and/or amplitude measurements, may be reflective of abnormalities within visual systems. This is a preliminary finding that may suggest the utility of performing VEP analysis in a larger sample of SSADH-deficient patients, and encourage a neurophysiological assessment of GABA(C) receptor function in Aldh5a1(-/-) mice to reveal new pathophysiological mechanisms of this rare disorder of GABA degradation.
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Affiliation(s)
- G Di Rosa
- Department of Medical and Surgical Pediatrics, Unit of Infantile Neuropsychiatry, University Hospital of Messina, via Consolare Valeria, Messina, 98125, Italy.
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31
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Pearl PL, Gibson KM, Quezado Z, Dustin I, Taylor J, Trzcinski S, Schreiber J, Forester K, Reeves-Tyer P, Liew C, Shamim S, Herscovitch P, Carson R, Butman J, Jakobs C, Theodore W. Decreased GABA-A binding on FMZ-PET in succinic semialdehyde dehydrogenase deficiency. Neurology 2009; 73:423-9. [PMID: 19667317 DOI: 10.1212/wnl.0b013e3181b163a5] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Succinic semialdehyde dehydrogenase (SSADH) deficiency is an autosomal recessive disorder of GABA metabolism characterized by elevated levels of GABA and gamma-hydroxybutyric acid. Clinical findings include intellectual impairment, hypotonia, hyporeflexia, hallucinations, autistic behaviors, and seizures. Autoradiographic labeling and slice electrophysiology studies in the murine model demonstrate use-dependent downregulation of GABA(A) receptors. We studied GABA(A) receptor activity in human SSADH deficiency utilizing [(11)C]-flumazenil (FMZ)-PET. METHODS FMZ binding was measured in 7 patients, 10 unaffected parents, and 8 healthy controls. Data analysis was performed using a reference region compartmental model, with time-activity curve from pons as the input function. Relative parametric binding potential (BP(ND)) was derived, with MRI-based pixel by pixel partial volume correction, in regions of interest drawn on coregistered MRI. RESULTS In amygdala, hippocampus, cerebellar vermis, frontal, parietal, and occipital cortex, patients with SSADH deficiency had significant reductions in FMZ BP(ND) compared to parents and controls. Mean cortical values were 6.96 +/- 0.79 (controls), 6.89 +/- 0.71 (parents), and 4.88 +/- 0.77 (patients) (F ratio 16.1; p < 0.001). There were no differences between controls and parents in any cortical region. CONCLUSIONS Succinic semialdehyde dehydrogenase (SSADH) deficient patients show widespread reduction in BZPR binding on [(11)C]-flumazenil-PET. Our results suggest that high endogenous brain GABA levels in SSADH deficiency downregulate GABA(A)-BZPR binding site availability. This finding suggests a potential mechanism for neurologic dysfunction in a serious neurodevelopmental disorder, and suggests that PET may be useful to translate studies in animal models to human disease.
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Affiliation(s)
- P L Pearl
- Department of Neurology, Children's National Medical Center, Washington, DC 20010-2970, USA.
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Pearl PL, Gibson KM, Cortez MA, Wu Y, Carter Snead O, Knerr I, Forester K, Pettiford JM, Jakobs C, Theodore WH. Succinic semialdehyde dehydrogenase deficiency: lessons from mice and men. J Inherit Metab Dis 2009; 32:343-52. [PMID: 19172412 PMCID: PMC2693236 DOI: 10.1007/s10545-009-1034-y] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Revised: 11/14/2008] [Accepted: 11/26/2008] [Indexed: 12/23/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH) deficiency, a disorder of GABA degradation with subsequent elevations in brain GABA and GHB, is a neurometabolic disorder with intellectual disability, epilepsy, hypotonia, ataxia, sleep disorders, and psychiatric disturbances. Neuroimaging reveals increased T2-weighted MRI signal usually affecting the globus pallidus, cerebellar dentate nucleus, and subthalamic nucleus, and often cerebral and cerebellar atrophy. EEG abnormalities are usually generalized spike-wave, consistent with a predilection for generalized epilepsy. The murine phenotype is characterized by failure-to-thrive, progressive ataxia, and a transition from generalized absence to tonic-clonic to ultimately fatal convulsive status epilepticus. Binding and electrophysiological studies demonstrate use-dependent downregulation of GABA(A) and (B) receptors in the mutant mouse. Translational human studies similarly reveal downregulation of GABAergic activity in patients, utilizing flumazenil-PET and transcranial magnetic stimulation for GABA(A) and (B) activity, respectively. Sleep studies reveal decreased stage REM with prolonged REM latencies and diminished percentage of stage REM. An ad libitum ketogenic diet was reported as effective in the mouse model, with unclear applicability to the human condition. Acute application of SGS-742, a GABA(B) antagonist, leads to improvement in epileptiform activity on electrocorticography. Promising mouse data using compounds available for clinical use, including taurine and SGS-742, form the framework for human trials.
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MESH Headings
- Animals
- Brain Diseases, Metabolic, Inborn/diagnosis
- Brain Diseases, Metabolic, Inborn/etiology
- Brain Diseases, Metabolic, Inborn/genetics
- Brain Diseases, Metabolic, Inborn/therapy
- Disease Models, Animal
- Humans
- Mice
- Mice, Transgenic
- Models, Biological
- Succinate-Semialdehyde Dehydrogenase/deficiency
- Succinate-Semialdehyde Dehydrogenase/genetics
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Affiliation(s)
- P L Pearl
- Department of Neurology, Children's National Medical Center, George Washington University School of Medicine, 111 Michigan Avenue, NW, Washington, DC 20010-2970, USA.
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Zhang Z, Lian XY, Li S, Stringer JL. Characterization of chemical ingredients and anticonvulsant activity of American skullcap (Scutellaria lateriflora). PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2009; 16:485-493. [PMID: 18786819 DOI: 10.1016/j.phymed.2008.07.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 07/04/2008] [Accepted: 07/29/2008] [Indexed: 05/26/2023]
Abstract
American skullcap (the aerial part of Scutellaria lateriflora L.) has been traditionally used by Native Americans and Europeans as a nerve tonic, sedative, and anticonvulsant. However, despite some previous studies, the quality and safety, the bioactive ingredients, and the pharmacological properties of American skullcap are not fully understood. The aims of this study were to characterize the chemical ingredients of American skullcap and to evaluate its anticonvulsant activity. Twelve phenolic compounds including 10 flavonoids and two phenylethanoid glycosides were isolated and identified from American skullcap and used as marker compounds. An HPLC analytic method for analyzing these marker compounds in commercial American skullcap products from different sources was established and validated. The anticonvulsant activity of American skullcap was determined in rat models of acute seizures induced by pilocarpine and pentylenetetrazol. The results from this study indicate that (1) phenolic compounds, especially flavonoids, are the predominant constituents in American skullcap; (2) American skullcap products have similar constituents, but the content and relative proportions of the individual constituents varies widely; and (3) American skullcap has anticonvulsant activity in rodent models of acute seizures.
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Affiliation(s)
- Zhizhen Zhang
- National Center for Pharmaceutical Crops, College of Forestry and Agriculture, Stephen F. Austin State University, Nacogdoches, TX 75961, USA.
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Comparative genomics of aldehyde dehydrogenase 5a1 (succinate semialdehyde dehydrogenase) and accumulation of gamma-hydroxybutyrate associated with its deficiency. Hum Genomics 2009; 3:106-20. [PMID: 19164088 PMCID: PMC2657722 DOI: 10.1186/1479-7364-3-2-106] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Succinic semialdehyde dehydrogenase (SSADH; aldehyde dehydrogenase 5A1 [ALDH5A1]; locus 6p22) occupies a central position in central nervous system (CNS) neurotransmitter metabolism as one of two enzymes necessary for γ-aminobutyric acid (GABA) recycling from the synaptic cleft. Its importance is highlighted by the neurometabolic disease associated with its inherited deficiency in humans, as well as the severe epileptic phenotype observed in Aldh5a1-/- knockout mice. Expanding evidence now suggests, however, that even subtle decreases in human SSADH activity, associated with rare and common single nucleotide polymorphisms, may produce subclinical pathological effects. SSADH, in conjunction with aldo-keto reductase 7A2 (AKR7A2), represent two neural enzymes responsible for further catabolism of succinic semialdehyde, producing either succinate (SSADH) or γ-hydroxybutyrate (GHB; AKR7A2). A GABA analogue, GHB is a short-chain fatty alcohol with unusual properties in the CNS and a long pharmacological history. Moreover, SSADH occupies a further role in the CNS as the enzyme responsible for further metabolism of the lipid peroxidation aldehyde 4-hydroxy-2-nonenal (4-HNE), an intermediate known to induce oxidant stress. Accordingly, subtle decreases in SSADH activity may have the capacity to lead to regional accumulation of neurotoxic intermediates (GHB, 4-HNE). Polymorphisms in SSADH gene structure may also associate with quantitative traits, including intelligence quotient and life expectancy. Further population-based studies of human SSADH activity promise to reveal additional properties of its function and additional roles in CNS tissue.
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Nylen K, Velazquez JLP, Sayed V, Gibson KM, Burnham WM, Snead OC. The effects of a ketogenic diet on ATP concentrations and the number of hippocampal mitochondria in Aldh5a1(-/-) mice. Biochim Biophys Acta Gen Subj 2009; 1790:208-12. [PMID: 19168117 DOI: 10.1016/j.bbagen.2008.12.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Revised: 12/14/2008] [Accepted: 12/23/2008] [Indexed: 11/19/2022]
Abstract
BACKGROUND Succinic semialdehyde dehydrogenase (SSADH) deficiency is an inborn error of GABA metabolism characterized clinically by ataxia, psychomotor retardation and seizures. A mouse model of SSADH deficiency, the Aldh5a1(-/-) mouse, has been used to study the pathophysiology and treatment of this disorder. Recent work from our group has shown that the ketogenic diet (KD) is effective in normalizing the Aldh5a1(-/-) phenotype, although the mechanism of the effect remains unclear. METHODS Here, we examine the effects of a KD on the number of hippocampal mitochondria as well as on ATP levels in hippocampus. Electron microscopy was performed to determine the number of mitochondria in the hippocampus of Aldh5a1(-/-) mice. Adenosine triphosphate (ATP) levels were measured in hippocampal extracts. RESULTS Our results show that the KD increases the number of mitochondria in Aldh5a1(-/-) mice. We also show that Aldh5a1(-/-) mice have significant reductions in hippocampal ATP levels as compared to controls, and that the KD restores ATP in mutant mice to normal levels. GENERAL SIGNIFICANCE Taken together, our data suggest that the KD's actions on brain mitochondria may play a role in the diet's ability to treat murine SSADH deficiency.
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Affiliation(s)
- Kirk Nylen
- Neuroscience and Mental Health, 6535 Hill Wing, Hospital for Sick Children, 555 University Avenue, Toronto, ON, Canada M5G 1X8.
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Drasbek KR, Vardya I, Delenclos M, Gibson KM, Jensen K. SSADH deficiency leads to elevated extracellular GABA levels and increased GABAergic neurotransmission in the mouse cerebral cortex. J Inherit Metab Dis 2008; 31:662-8. [PMID: 18696252 PMCID: PMC2596865 DOI: 10.1007/s10545-008-0941-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Revised: 07/03/2008] [Accepted: 07/11/2008] [Indexed: 12/01/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH) deficiency is an inherited disorder in which patients display neurodevelopmental retardation, ataxia, and epileptic seizures. The recently engineered SSADH knock-out (KO) mouse models the severe form of the human disorder. The SSADH enzyme participates in the breakdown of the inhibitory neurotransmitter GABA, and studies have shown increases in brain GABA and downregulation of GABA(A) receptor beta(2) subunits in the cerebral cortex of these mice. Here, we used brain slice electrophysiology to investigate the alterations in GABA neurotransmission in SSADH KO mouse cortex. In layer 2/3 pyramidal cells, spontaneous inhibitory postsynaptic currents (IPSCs), reflecting activity of GABAergic synaptic contacts, were normal in SSADH KO mice. Also, IPSCs evoked by electrical single-axon stimulation in KO mice were normal. In contrast, tonic inhibition mediated by presumed extrasynaptic GABA(A) receptors was strongly increased, indicating significantly raised extracellular GABA levels. The excessive cortical GABAergic neurotransmission may participate in the seizure activity in SSADH deficiency.
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Affiliation(s)
- K R Drasbek
- Synaptic Physiology Laboratory, Institute of Physiology and Biophysics, University of Aarhus, Aarhus, Denmark
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Neurotransmitter alterations in embryonic succinate semialdehyde dehydrogenase (SSADH) deficiency suggest a heightened excitatory state during development. BMC DEVELOPMENTAL BIOLOGY 2008; 8:112. [PMID: 19040727 PMCID: PMC2642797 DOI: 10.1186/1471-213x-8-112] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Accepted: 11/28/2008] [Indexed: 11/10/2022]
Abstract
BACKGROUND SSADH (aldehyde dehydrogenase 5a1 (Aldh5a1); gamma-hydroxybutyric (GHB) aciduria) deficiency is a defect of GABA degradation in which the neuromodulators GABA and GHB accumulate. The human phenotype is that of nonprogressive encephalopathy with prominent bilateral discoloration of the globi pallidi and variable seizures, the latter displayed prominently in Aldh5a1-/- mice with lethal convulsions. Metabolic studies in murine neural tissue have revealed elevated GABA [and its derivatives succinate semialdehyde (SSA), homocarnosine (HC), 4,5-dihydroxyhexanoic acid (DHHA) and guanidinobutyrate (GB)] and GHB [and its analogue D-2-hydroxyglutarate (D-2-HG)] at birth. Because of early onset seizures and the neurostructural anomalies observed in patients, we examined metabolite features during Aldh5a1-/- embryo development. METHODS Embryos were obtained from pregnant dams sacrificed at E (embryo day of life) 10-13, 14-15, 16-17, 18-19 and newborn mice. Intact embryos were extracted and metabolites quantified by isotope dilution mass spectrometry (n = 5-15 subjects, Aldh5a1+/+ and Aldh5a1-/-) for each gestational age group. Data was evaluated using the t test and one-way ANOVA with Tukey post hoc analysis. Significance was set at the 95th centile. RESULTS GABA and DHHA were significantly elevated at all gestational ages in Aldh5a1-/- mice, while GB was increased only late in gestation; SSA was not elevated at any time point. GHB and D-2-HG increased in an approximately linear fashion with gestational age. Correlative studies in human amniotic fluid from SSADH-deficient pregnancies (n = 5) also revealed significantly increased GABA. CONCLUSION Our findings indicate early GABAergic alterations in Aldh5a1-/- mice, possibly exacerbated by other metabolites, which likely induce a heightened excitatory state that may predispose neural networks to epilepsy in these animals.
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Crutchfield SR, Haas RH, Nyhan WL, Gibson KM. 'Succinic semialdehyde dehydrogenase deficiency: phenotype evolution in an adolescent patient at 20-year follow-up'. Dev Med Child Neurol 2008; 50:880-1. [PMID: 18811705 PMCID: PMC2668832 DOI: 10.1111/j.1469-8749.2008.03116.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Susan R Crutchfield
- Department of Neurosciences; University of California San Diego, La Jolla, CA
| | - Richard H Haas
- Department of Neurosciences; University of California San Diego, La Jolla, CA,Department of Pediatrics; University of California San Diego, La Jolla, CA
| | - William L Nyhan
- Department of Neurosciences; University of California San Diego, La Jolla, CA,Center for Molecular Genetics, University of California San Diego, La Jolla, CA
| | - K Michael Gibson
- Division of Medical Genetics, Departments of Pediatrics, Pathology and Human Genetics, University of Pittsburgh School of Medicine and the Graduate School of Public Health, Children's Hospital of Pittsburgh of UPMC, Clinical Biochemical Genetics Laboratory, Pittsburgh, PA, USA.,Correspondence to:
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Stewart LS, Nylen KJ, Persinger MA, Cortez MA, Gibson KM, Snead OC. Circadian distribution of generalized tonic-clonic seizures associated with murine succinic semialdehyde dehydrogenase deficiency, a disorder of GABA metabolism. Epilepsy Behav 2008; 13:290-4. [PMID: 18514581 PMCID: PMC2574901 DOI: 10.1016/j.yebeh.2008.04.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Revised: 04/17/2008] [Accepted: 04/18/2008] [Indexed: 11/29/2022]
Abstract
Human succinic semialdehyde dehydrogenase (SSADH) deficiency is an autosomal recessive disorder of GABA metabolism associated with motor impairment and epileptic seizures. Similarly, mice with targeted deletion of the Aldh5a1 gene (Aldh5a1(-/-)) exhibit SSADH deficiency and seizures early in life. These seizures begin as absence seizures the second week of life, but evolve into generalized convulsive seizures that increase in severity and become lethal during the fourth postnatal week. The seizures are alleviated and survival is prolonged when the mutant animals are weaned onto a ketogenic diet (KD). The persistence of spontaneous, recurrent, generalized tonic-clonic seizures in KD-treated adult Aldh5a1(-/-) mice allowed us to quantify their daily (circadian) distribution using a novel behavioral method based on the detection of changes in movement velocity. Adult KD-treated Aldh5a1(-/-) mice exhibited a seizure phenotype characterized by fits of wild running clonus accompanied by jumping and bouncing. These hypermotor seizures were largely spontaneous and occurred daily in a nonrandom pattern. The seizure rhythm showed a peak shortly after dark phase onset (2008 hours) with near-24-hour periodicity. Age-matched wild-type littermates showed no evidence of abnormal motor behavior. These new data suggest that generalized tonic-clonic seizures in Aldh5a1(-/-) mice are more frequent during a specific time of day and will provide useful information to clinicians for the treatment of seizures associated with human SSADH deficiency.
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Affiliation(s)
- Lee S. Stewart
- Neurosciences and Mental Health Research Program, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8
| | - Kirk J. Nylen
- Neurosciences and Mental Health Research Program, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8
| | - Michael A. Persinger
- Behavioral Neuroscience Program, Department of Psychology, Laurentian University, Sudbury ON, Canada P3E 2C6
| | - Miguel A. Cortez
- Neurosciences and Mental Health Research Program, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8, Division of Neurology, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8, Department of Pediatrics, Faculty of Medicine, University of Toronto, 190 Elizabeth Street, Toronto ON, Canada M5G 2C4
| | - K. Michael Gibson
- Division of Medical Genetics, Departments of Pediatrics and Pathology, University of Pittsburgh School of Medicine, Rangos Research Center, 3460 Fifth Avenue, Pittsburgh PA 15213, USA
| | - O. Carter Snead
- Neurosciences and Mental Health Research Program, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8, Division of Neurology, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8, Department of Pediatrics, Faculty of Medicine, University of Toronto, 190 Elizabeth Street, Toronto ON, Canada M5G 2C4, Corresponding author. Address: Neurosciences and Mental Health Research Program, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8. Fax: +1 416 813 6334. E-mail address: (O.C. Snead, III)
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Neuropsychiatric morbidity in adolescent and adult succinic semialdehyde dehydrogenase deficiency patients. CNS Spectr 2008; 13:598-605. [PMID: 18622364 PMCID: PMC2562649 DOI: 10.1017/s1092852900016874] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Succinic semialdehyde dehydrogenase (SSADH) deficiency (gamma-hydroxybutyric aciduria) is a rare neurometabolic disorder of gamma-aminobutyric acid degradation. While neurological manifestations, such as developmental delay, are typical during infancy, limited data are available on adolescent and adult symptomatology. METHODS We overview the phenotype of 33 adolescents and adults (10.1-39.5 years of age, mean: 17.1 years, 48% females) with SSADH deficiency. For this purpose, we applied a database with systematic questionnaire-based follow-up data. RESULTS Sixty-six percent of patients (n=21) presented by 6 months of age, 14% from 6-12 months of age, 5% from 1-2 years of age, and 14% from 2-4 years of age, mean age at first symptoms was 11+/-12 months. However, mean age at diagnosis was 6.6+/-6.4 years of age. Presenting symptoms encompassed motor delay, hypotonia, speech delay, autistic features, seizures, and ataxia. Eighty-two percent demonstrated behavioral problems, such as attention deficit, hyperactivity, anxiety, or aggression, and 33% had >or=3 behavior problems. Electroencephalograms showed background slowing or epileptiform discharges in 40% of patients. Treatment approaches are then summarized. CONCLUSION The variable phenotype in SSADH deficiency suggests the likelihood that this disease may be under-diagnosed. Families of patients with SSADH deficiency should be counseled and supported regarding the anticipated persistence of various neuropsychiatric symptoms into adulthood.
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Lambrechtsen FACP, Buchhalter JR. Aborted and refractory status epilepticus in children: A comparative analysis. Epilepsia 2008; 49:615-25. [DOI: 10.1111/j.1528-1167.2007.01465.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kölker S, Sauer SW, Hoffmann GF, Müller I, Morath MA, Okun JG. Pathogenesis of CNS involvement in disorders of amino and organic acid metabolism. J Inherit Metab Dis 2008; 31:194-204. [PMID: 18392748 DOI: 10.1007/s10545-008-0823-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Revised: 02/12/2008] [Accepted: 02/14/2008] [Indexed: 12/21/2022]
Abstract
Inherited disorders of amino and organic acid metabolism have a high cumulative frequency, and despite heterogeneous aetiology and varying clinical presentation, the manifestation of neurological disease is common. It has been demonstrated for some of these diseases that accumulating pathological metabolites are directly involved in the manifestation of neurological disease. Various pathomechanisms have been suggested in different in vitro and in vivo models including an impairment of brain energy metabolism, an imbalance of excitatory and inhibitory neurotransmission, altered transport across the blood-brain barrier and between glial cells and neurons, impairment of myelination and disturbed neuronal efflux of metabolic water. This review summarizes recent knowledge on pathomechanisms involved in phenylketonuria, glutaric aciduria type I, succinic semialdehyde dehydrogenase deficiency and aspartoacylase deficiency with examples, highlighting general as well as disease-specific concepts and their putative impact on treatment.
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Affiliation(s)
- S Kölker
- Department of General Pediatrics, Division of Inherited Metabolic Disease, University Children’s Hospital Heidelberg, Heidelberg, Germany.
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Nylen K, Velazquez JLP, Likhodii SS, Cortez MA, Shen L, Leshchenko Y, Adeli K, Gibson KM, Burnham WM, Snead OC. A ketogenic diet rescues the murine succinic semialdehyde dehydrogenase deficient phenotype. Exp Neurol 2007; 210:449-57. [PMID: 18199435 DOI: 10.1016/j.expneurol.2007.11.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 11/14/2007] [Accepted: 11/15/2007] [Indexed: 10/22/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH) deficiency is a heritable disorder of GABA degradation characterized by ataxia, psychomotor retardation and seizures. To date, there is no effective treatment for SSADH deficiency. We tested the hypothesis that a ketogenic diet (KD) would improve outcome in an animal model of SSADH deficiency, the SSADH knockout mouse (Aldh5a1-/-). Using a 4:1 ratio of fat to combined carbohydrate and protein KD we set out to compare the general phenotype, in vivo and in vitro electrophysiology and [35S]TBPS binding in both Aldh5a1-/- mice and control (Aldh5a1+/+) mice. We found that the KD prolonged the lifespan of mutant mice by >300% with normalization of ataxia, weight gain and EEG compared to mutants fed a control diet. Aldh5a1-/- mice showed significantly reduced mIPSC frequency in CA1 hippocampal neurons as well as significantly decreased [35S]TBPS binding in all brain areas examined. In KD fed mutants, mIPSC activity normalized and [35S]TBPS binding was restored in the cortex and hippocampus. The KD appears to reverse toward normal the perturbations seen in Aldh5a1-/- mice. Our data suggest that the KD may work in this model by restoring GABAergic inhibition. These data demonstrate a successful experimental treatment for murine SSADH deficiency using a KD, giving promise to the idea that the KD may be successful in the clinical treatment of SSADH deficiency.
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Affiliation(s)
- Kirk Nylen
- Program in Neuroscience and Mental Health, Hospital for Sick Children, and Department of Pharmacology, University of Toronto, Ontario, Canada.
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Chowdhury GMI, Gupta M, Gibson KM, Patel AB, Behar KL. Altered cerebral glucose and acetate metabolism in succinic semialdehyde dehydrogenase-deficient mice: evidence for glial dysfunction and reduced glutamate/glutamine cycling. J Neurochem 2007; 103:2077-91. [PMID: 17854388 DOI: 10.1111/j.1471-4159.2007.04887.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH) catalyzes the NADP-dependent oxidation of succinic semialdehyde to succinate, the final step of the GABA shunt pathway. SSADH deficiency in humans is associated with excessive elevation of GABA and gamma-hydroxybutyrate (GHB). Recent studies of SSADH-null mice show that elevated GABA and GHB are accompanied by reduced glutamine, a known precursor of the neurotransmitters glutamate and GABA. In this study, cerebral metabolism was investigated in urethane-anesthetized SSADH-null and wild-type 17-day-old mice by intraperitoneal infusion of [1,6-(13)C(2)]glucose or [2-(13)C]acetate for different periods. Cortical extracts were prepared and measured using high-resolution (1)H-[(13)C] NMR spectroscopy. Compared with wild-type, levels of GABA, GHB, aspartate, and alanine were significantly higher in SSADH-null cortex, whereas glutamate, glutamine, and taurine were lower. (13)C Labeling from [1,6-(13)C(2)]glucose, which is metabolized in neurons and glia, was significantly lower (expressed as mumol of (13)C incorporated per gram of brain tissue) for glutamate-(C4,C3), glutamine-C4, succinate-(C3/2), and aspartate-C3 in SSADH-null cortex, whereas Ala-C3 was higher and GABA-C2 unchanged. (13)C Labeling from [2-(13)C]acetate, a glial substrate, was lower mainly in glutamine-C4 and glutamate-(C4,C3). GHB was labeled by both substrates in SSADH-null mice consistent with GABA as precursor. Our findings indicate that SSADH deficiency is associated with major alterations in glutamate and glutamine metabolism in glia and neurons with surprisingly lesser effects on GABA synthesis.
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Affiliation(s)
- G M I Chowdhury
- Department of Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA.
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D'Hulst C, Kooy RF. The GABAA receptor: a novel target for treatment of fragile X? Trends Neurosci 2007; 30:425-31. [PMID: 17590448 DOI: 10.1016/j.tins.2007.06.003] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Revised: 05/11/2007] [Accepted: 06/06/2007] [Indexed: 11/29/2022]
Abstract
GABA(A) receptors are the major inhibitory neurotransmitter receptors in the mammalian brain, implicated in anxiety, depression, epilepsy, insomnia, and learning and memory. Here, we present several lines of evidence for involvement of the GABAergic system, and in particular the GABA(A) receptor-mediated function, in fragile X syndrome, the most common form of inherited mental retardation. We argue that an altered expression of the GABA(A) receptor has neurophysiologic and functional consequences that might relate to the behavioural and neurological phenotype associated with fragile X syndrome. Interestingly, some neuropsychiatric disorders, such as anxiety, epilepsy and sleep disorders, are effectively treated with therapeutic agents that act on the GABA(A) receptor. Therefore, the GABA(A) receptor might be a novel therapeutic target for fragile X syndrome.
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Affiliation(s)
- Charlotte D'Hulst
- Department of Medical Genetics, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium.
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Knerr I, Pearl PL, Bottiglieri T, Snead OC, Jakobs C, Gibson KM. Therapeutic concepts in succinate semialdehyde dehydrogenase (SSADH; ALDH5a1) deficiency (gamma-hydroxybutyric aciduria). Hypotheses evolved from 25 years of patient evaluation, studies in Aldh5a1-/- mice and characterization of gamma-hydroxybutyric acid pharmacology. J Inherit Metab Dis 2007; 30:279-94. [PMID: 17457693 DOI: 10.1007/s10545-007-0574-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Revised: 02/02/2007] [Accepted: 02/14/2007] [Indexed: 02/07/2023]
Abstract
We overview the pathophysiological bases, clinical approaches and potential therapeutic options for succinate semialdehyde dehydrogenase (SSADH; EC1.2.1.24) deficiency (gamma-hydroxybutyric aciduria, OMIM 271980, 610045) in relation to studies on SSADH gene-deleted mice, outcome data developed from 25 years of patient evaluation, and characterization of gamma-hydroxybutyric acid (GHB) pharmacology in different species. The clinical picture of this disorder encompasses a wide spectrum of neurological and psychiatric dysfunction, such as psychomotor retardation, delayed speech development, epileptic seizures and behavioural disturbances, emphasizing the multifactorial pathophysiology of SSADH deficiency. The murine SSADH-/- (e.g. Aldh5a1-/-) mouse model suffers from epileptic seizures and succumbs to early lethality. Aldh5a1-/- mice accumulate GHB and gamma-aminobutyric acid (GABA) in the central nervous system, exhibit alterations of amino acids such as glutamine (Gln), alanine (Ala) and arginine (Arg), and manifest disturbances in other systems including dopamine, neurosteroids and antioxidant status. Therapeutic concepts in patients with SSADH deficiency and preclinical therapeutic experiments are discussed in light of data collected from research in Aldh5a1-/- mice and animal studies of GHB pharmacology; these studies are the foundation for novel working approaches, including pharmacological and dietary trials, which are presented for future evaluation in this disease.
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Affiliation(s)
- I Knerr
- Children's and Adolescents' Hospital, University of Erlangen-Nuremberg, Erlangen, Germany
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Abstract
The pediatric neurotransmitter disorders represent an enlarging group of neurological syndromes characterized by abnormalities of neurotransmitter synthesis and breakdown. The disorders of dopamine and serotonin synthesis are aromatic amino acid decarboxylase deficiency, tyrosine hydroxylase deficiency, and disorders of tetrahydrobiopterin synthesis. Amino acid decarboxylase, tyrosine hydroxylase, sepiapterin reductase, and guanosine triphosphate cyclohydrolase (Segawa disease) deficiencies do not feature elevated serum phenylalanine and require cerebrospinal fluid analysis for diagnosis. Segawa disease is characterized by dramatic and lifelong responsiveness to levodopa. Glycine encephalopathy is typically manifested by refractory neonatal seizures secondary to a defect of the glycine degradative pathway. gamma-amino butyric acid (GABA) metabolism is associated with several disorders, including glutamic acid decarboxylase deficiency with nonsyndromic cleft lip/ palate, GABA-transaminase deficiency, and succinic semialdehyde dehydrogenase deficiency. The latter is characterized by elevated gamma-hydroxybutyric acid and includes a wide range of neuropsychiatric symptoms as well as epilepsy. Pyridoxine-dependent seizures have now been associated with deficiency of alpha-aminoadipic semialdehyde dehydrogenase, as well as a new variant requiring therapy with pyridoxal-5-phosphate, the biologically active form of pyridoxine.
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Affiliation(s)
- Phillip L Pearl
- Department of Neurology, Children's National Medical Center, The George Washington University School of Medicine, Washington, DC 20010, USA.
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Barcelo-Coblijn G, Murphy EJ, Mills K, Winchester B, Jakobs C, Snead O, Gibson KM. Lipid abnormalities in succinate semialdehyde dehydrogenase (Aldh5a1-/-) deficient mouse brain provide additional evidence for myelin alterations. Biochim Biophys Acta Mol Basis Dis 2007; 1772:556-62. [PMID: 17300923 PMCID: PMC2362103 DOI: 10.1016/j.bbadis.2006.12.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Revised: 12/20/2006] [Accepted: 12/21/2006] [Indexed: 10/23/2022]
Abstract
Earlier work from our laboratory provided evidence for myelin abnormalities (decreased quantities of proteins associated with myelin compaction, decreased sheath thickness) in cortex and hippocampus of Aldh5a1(-/-) mice, which have a complete ablation of the succinate semialdehyde dehydrogenase protein [E.A. Donarum, D.A. Stephan, K. Larkin, E.J. Murphy, M. Gupta, H. Senephansiri, R.C. Switzer, P.L. Pearl, O.C. Snead, C. Jakobs, K.M. Gibson, Expression profiling reveals multiple myelin alterations in murine succinate semialdehyde dehydrogenase deficiency, J. Inher. Metab. Dis. 29 (2006) 143-156]. In the current report, we have extended these findings via comprehensive analysis of brain phospholipid fractions, including quantitation of fatty acids in individual phospholipid subclasses and estimation of hexose-ceramide in Aldh5a1(-/-) brain. In comparison to wild-type littermates (Aldh5a1(+/+)), we detected a 20% reduction in the ethanolamine glycerophospholipid content of Aldh5a1(-/-)mice, while other brain phospholipids (choline glycerophospholipid, phosphatidylserine and phosphatidylinositol) were within normal limits. Analysis of individual fatty acids in each of these fractions revealed consistent alterations in n-3 fatty acids, primarily increased 22:6n-3 levels (docosahexaenoic acid; DHA). In the phosphatidyl serine fraction there were marked increases in the proportions of polyunsaturated fatty acids with corresponding decreases of monounsaturated fatty acids. Interestingly, the levels of hexose-ceramide (glucosyl- and galactosylceramide, principal myelin cerebrosides) were decreased in Aldh5a1(-/-) brain tissue (one-tailed t test, p=0.0449). The current results suggest that lipid and myelin abnormalities in this animal may contribute to the pathophysiology.
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Affiliation(s)
- G. Barcelo-Coblijn
- Department of Pharmacology, Physiology, and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, USA
| | - E. J. Murphy
- Department of Pharmacology, Physiology, and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, USA
| | - K. Mills
- Biochemistry, Endocrinology & Metabolism Unit, UCL Institute of Child Health at Great Ormond Street Hospital, University College, London, United Kingdom
| | - B. Winchester
- Biochemistry, Endocrinology & Metabolism Unit, UCL Institute of Child Health at Great Ormond Street Hospital, University College, London, United Kingdom
| | - C. Jakobs
- VU University Medical Center, Amsterdam, the Netherlands
| | - O.C. Snead
- Brain and Behavior Program, Division of Neurology and Department of Pediatrics, Faculty of Medicine, Hospital for Sick Children and University of Toronto, Ontario, Canada
| | - KM Gibson
- Division of Medical Genetics, Departments of Pediatrics, Pathology and Human Genetics, Children’s Hospital Pittsburgh and the University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- *Correspondence: Rangos Research Building, Room 2111, Children’s Hospital Pittsburgh, 3460 Fifth Ave., Pittsburgh, PA, 15213; 412-692-7608; fax 412-692-7816;
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Idiopathic Generalized Epilepsy. Neurobiol Dis 2007. [DOI: 10.1016/b978-012088592-3/50030-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] Open
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50
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Pearl PL. Inherited neurotransmitter disorders: a rapidly enlarging field of neurometabolism in children and adults. FUTURE NEUROLOGY 2006. [DOI: 10.2217/14796708.1.5.589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Phillip L Pearl
- Children’s National Medical Center, Department of Neurology, 111 Michigan Avenue, NW Washington, DC 20010-2970, USA
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