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Chu WS, Ng J, Waddington SN, Kurian MA. Gene therapy for neurotransmitter-related disorders. J Inherit Metab Dis 2024; 47:176-191. [PMID: 38221762 PMCID: PMC11108624 DOI: 10.1002/jimd.12697] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 11/14/2023] [Accepted: 11/28/2023] [Indexed: 01/16/2024]
Abstract
Inborn errors of neurotransmitter (NT) metabolism are a group of rare, heterogenous diseases with predominant neurological features, such as movement disorders, autonomic dysfunction, and developmental delay. Clinical overlap with other disorders has led to delayed diagnosis and treatment, and some conditions are refractory to oral pharmacotherapies. Gene therapies have been developed and translated to clinics for paediatric inborn errors of metabolism, with 38 interventional clinical trials ongoing to date. Furthermore, efforts in restoring dopamine synthesis and neurotransmission through viral gene therapy have been developed for Parkinson's disease. Along with the recent European Medicines Agency (EMA) and Medicines and Healthcare Products Regulatory Agency (MHRA) approval of an AAV2 gene supplementation therapy for AADC deficiency, promising efficacy and safety profiles can be achieved in this group of diseases. In this review, we present preclinical and clinical advances to address NT-related diseases, and summarise potential challenges that require careful considerations for NT gene therapy studies.
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Affiliation(s)
- Wing Sum Chu
- Gene Transfer Technology Group, EGA Institute for Women's HealthUniversity College LondonLondonUK
- Genetic Therapy Accelerator Centre, Queen Square Institute of NeurologyUniversity College LondonLondonUK
| | - Joanne Ng
- Gene Transfer Technology Group, EGA Institute for Women's HealthUniversity College LondonLondonUK
- Genetic Therapy Accelerator Centre, Queen Square Institute of NeurologyUniversity College LondonLondonUK
| | - Simon N. Waddington
- Gene Transfer Technology Group, EGA Institute for Women's HealthUniversity College LondonLondonUK
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health SciencesUniversity of the WitwatersrandJohannesburgSouth Africa
| | - Manju A. Kurian
- Developmental Neurosciences, Zayed Centre for Research into Rare Disease in Children, Great Ormond Street Institute of Child HealthUniversity College LondonLondonUK
- Department of NeurologyGreat Ormond Street Hospital for ChildrenLondonUK
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2
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Afshar-Saber W, Teaney NA, Winden KD, Jumo H, Shi X, McGinty G, Hubbs J, Chen C, Tokatly Latzer I, Gasparoli F, Ebrahimi-Fakhari D, Buttermore ED, Roullet JB, Pearl PL, Sahin M. ALDH5A1-deficient iPSC-derived excitatory and inhibitory neurons display cell type specific alterations. Neurobiol Dis 2024; 190:106386. [PMID: 38110041 PMCID: PMC10843729 DOI: 10.1016/j.nbd.2023.106386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 12/20/2023] Open
Abstract
Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a neurometabolic disorder caused by ALDH5A1 mutations presenting with autism and epilepsy. SSADHD leads to impaired GABA metabolism and results in accumulation of GABA and γ-hydroxybutyrate (GHB), which alter neurotransmission and are thought to lead to neurobehavioral symptoms. However, why increased inhibitory neurotransmitters lead to seizures remains unclear. We used induced pluripotent stem cells from SSADHD patients (one female and two male) and differentiated them into GABAergic and glutamatergic neurons. SSADHD iGABA neurons show altered GABA metabolism and concomitant changes in expression of genes associated with inhibitory neurotransmission. In contrast, glutamatergic neurons display increased spontaneous activity and upregulation of mitochondrial genes. CRISPR correction of the pathogenic variants or SSADHD mRNA expression rescue various metabolic and functional abnormalities in human neurons. Our findings uncover a previously unknown role for SSADHD in excitatory human neurons and provide unique insights into the cellular and molecular basis of SSADHD and potential therapeutic interventions.
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Affiliation(s)
- Wardiya Afshar-Saber
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Nicole A Teaney
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Kellen D Winden
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Hellen Jumo
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Xutong Shi
- Washington State University, Department of Pharmacotherapy, Spokane, WA, USA
| | - Gabrielle McGinty
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jed Hubbs
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Cidi Chen
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Human Neuron Core, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA, USA
| | - Itay Tokatly Latzer
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | | | - Darius Ebrahimi-Fakhari
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Elizabeth D Buttermore
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Human Neuron Core, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA, USA
| | | | - Phillip L Pearl
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Mustafa Sahin
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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3
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Chen X, Peng M, Cai Y, Zhou C, Liu L. Human iPSC-derived neural stem cells with ALDH5A1 mutation as a model of succinic semialdehyde dehydrogenase deficiency. BMC Neurosci 2022; 23:77. [PMID: 36527006 PMCID: PMC9756581 DOI: 10.1186/s12868-022-00755-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 11/11/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Succinic semialdehyde dehydrogenase deficiency (SSADH-D) is an autosomal recessive gamma-aminobutyric acid (GABA) metabolism disorder that can arise due to ALDH5A1 mutations, resulting in severe, progressive, untreatable neurodegeneration. SSADH-D is primarily studied using simplified models, such as HEK293 cells overexpressing genes of interest, but such overexpression can result in protein aggregation or pathway saturation that may not be representative of actual underlying disease phenotypes. METHODS We used a CRISPR/Cas9 approach to generate human iPSC cell lines bearing ALDH5A1 mutations. Through screening, two different mutant cell lines, NM_001080.3: c.727_735del (p.L243_S245del) and NM_001080.3: c.730_738del (p.A244_Q246del), were obtained. We induced iPSCs to neural stem cells and analyzed the characteristics of ALDH5A1 mutations in stem cells. RESULTS The human iPSC and NSC cell lines presented typical stem cell-like morphology. We found changes in ALDH5A1 expression and GABA accumulation in the different cell lines. In addition, by analyzing the cDNA between the wild-type and the mutant cell lines, we found that the mutant cell lines had a splicing variant. CONCLUSIONS iPSCs represent a promising in vitro model for SSADH-D that can be used to study early central nervous system developmental alterations and pathogenic mechanisms.
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Affiliation(s)
- Xiaodan Chen
- grid.410737.60000 0000 8653 1072Department of Genetics and Endocrinology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of China
| | - Minzhi Peng
- grid.410737.60000 0000 8653 1072Department of Genetics and Endocrinology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of China
| | - Yanna Cai
- grid.410737.60000 0000 8653 1072Department of Genetics and Endocrinology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of China
| | - Chengcheng Zhou
- grid.410737.60000 0000 8653 1072Department of Genetics and Endocrinology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of China
| | - Li Liu
- grid.410737.60000 0000 8653 1072Department of Genetics and Endocrinology, Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, People’s Republic of China
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4
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Lee HHC, McGinty GE, Pearl PL, Rotenberg A. Understanding the Molecular Mechanisms of Succinic Semialdehyde Dehydrogenase Deficiency (SSADHD): Towards the Development of SSADH-Targeted Medicine. Int J Mol Sci 2022; 23:2606. [PMID: 35269750 PMCID: PMC8910003 DOI: 10.3390/ijms23052606] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/18/2022] [Accepted: 02/21/2022] [Indexed: 11/21/2022] Open
Abstract
Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a rare genetic disorder caused by inefficient metabolic breakdown of the major inhibitory neurotransmitter, γ-aminobutyric acid (GABA). Pathologic brain accumulation of GABA and γ-hydroxybutyrate (GHB), a neuroactive by-product of GABA catabolism, leads to a multitude of molecular abnormalities beginning in early life, culminating in multifaceted clinical presentations including delayed psychomotor development, intellectual disability, hypotonia, and ataxia. Paradoxically, over half of patients with SSADHD also develop epilepsy and face a significant risk of sudden unexpected death in epilepsy (SUDEP). Here, we review some of the relevant molecular mechanisms through which impaired synaptic inhibition, astrocytic malfunctions and myelin defects might contribute to the complex SSADHD phenotype. We also discuss the gaps in knowledge that need to be addressed for the implementation of successful gene and enzyme replacement SSADHD therapies. We conclude with a description of a novel SSADHD mouse model that enables 'on-demand' SSADH restoration, allowing proof-of-concept studies to fine-tune SSADH restoration in preparation for eventual human trials.
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Affiliation(s)
- Henry H. C. Lee
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA; (G.E.M.); (A.R.)
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Gabrielle E. McGinty
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA; (G.E.M.); (A.R.)
| | - Phillip L. Pearl
- Division of Epilepsy & Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA 02115, USA;
| | - Alexander Rotenberg
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA; (G.E.M.); (A.R.)
- Division of Epilepsy & Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA 02115, USA;
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5
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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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6
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Succinic Semialdehyde Dehydrogenase Deficiency: In Vitro and In Silico Characterization of a Novel Pathogenic Missense Variant and Analysis of the Mutational Spectrum of ALDH5A1. Int J Mol Sci 2020; 21:ijms21228578. [PMID: 33203024 PMCID: PMC7696157 DOI: 10.3390/ijms21228578] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/09/2020] [Accepted: 11/11/2020] [Indexed: 12/16/2022] Open
Abstract
Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a rare, monogenic disorder affecting the degradation of the main inhibitory neurotransmitter γ-amino butyric acid (GABA). Pathogenic variants in the ALDH5A1 gene that cause an enzymatic dysfunction of succinic semialdehyde dehydrogenase (SSADH) lead to an accumulation of potentially toxic metabolites, including γ-hydroxybutyrate (GHB). Here, we present a patient with a severe phenotype of SSADHD caused by a novel genetic variant c.728T > C that leads to an exchange of leucine to proline at residue 243, located within the highly conserved nicotinamide adenine dinucleotide (NAD)+ binding domain of SSADH. Proline harbors a pyrrolidine within its side chain known for its conformational rigidity and disruption of protein secondary structures. We investigate the effect of this novel variant in vivo, in vitro, and in silico. We furthermore examine the mutational spectrum of all previously described disease-causing variants and computationally assess all biologically possible missense variants of ALDH5A1 to identify mutational hotspots.
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7
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Vernau KM, Struys E, Letko A, Woolard KD, Aguilar M, Brown EA, Cissell DD, Dickinson PJ, Shelton GD, Broome MR, Gibson KM, Pearl PL, König F, Van Winkle TJ, O’Brien D, Roos B, Matiasek K, Jagannathan V, Drögemüller C, Mansour TA, Brown CT, Bannasch DL. A Missense Variant in ALDH5A1 Associated with Canine Succinic Semialdehyde Dehydrogenase Deficiency (SSADHD) in the Saluki Dog. Genes (Basel) 2020; 11:genes11091033. [PMID: 32887425 PMCID: PMC7565783 DOI: 10.3390/genes11091033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 02/07/2023] Open
Abstract
Dogs provide highly valuable models of human disease due to the similarity in phenotype presentation and the ease of genetic analysis. Seven Saluki puppies were investigated for neurological abnormalities including seizures and altered behavior. Magnetic resonance imaging showed a diffuse, marked reduction in cerebral cortical thickness, and symmetrical T2 hyperintensity in specific brain regions. Cerebral cortical atrophy with vacuolation (status spongiosus) was noted on necropsy. Genome-wide association study of 7 affected and 28 normal Salukis revealed a genome-wide significantly associated region on CFA 35. Whole-genome sequencing of three confirmed cases from three different litters revealed a homozygous missense variant within the aldehyde dehydrogenase 5 family member A1 (ALDH5A1) gene (XM_014110599.2: c.866G>A; XP_013966074.2: p.(Gly288Asp). ALDH5A1 encodes a succinic semialdehyde dehydrogenase (SSADH) enzyme critical in the gamma-aminobutyric acid neurotransmitter (GABA) metabolic pathway. Metabolic screening of affected dogs showed markedly elevated gamma-hydroxybutyric acid in serum, cerebrospinal fluid (CSF) and brain, and elevated succinate semialdehyde in urine, CSF and brain. SSADH activity in the brain of affected dogs was low. Affected Saluki dogs had striking similarities to SSADH deficiency in humans although hydroxybutyric aciduria was absent in affected dogs. ALDH5A1-related SSADH deficiency in Salukis provides a unique translational large animal model for the development of novel therapeutic strategies.
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Affiliation(s)
- Karen M. Vernau
- Department of Surgical and Radiological Sciences, University of California Davis, Davis, CA 95616, USA; (D.D.C.); (P.J.D.)
- Correspondence: (K.M.V.); (D.L.B.)
| | - Eduard Struys
- Department of Clinical Chemistry, VU University Medical Center, 1081 HV Amsterdam, The Netherlands; (E.S.); (B.R.)
| | - Anna Letko
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland; (A.L.); (V.J.); (C.D.)
| | - Kevin D. Woolard
- Department of Pathology, Microbiology and Immunology, University of California Davis, Davis, CA 95616, USA;
| | - Miriam Aguilar
- Department of Population Health and Reproduction, University of California Davis, Davis, CA 95616, USA; (M.A.); (E.A.B.); (T.A.M.); (C.T.B.)
| | - Emily A. Brown
- Department of Population Health and Reproduction, University of California Davis, Davis, CA 95616, USA; (M.A.); (E.A.B.); (T.A.M.); (C.T.B.)
| | - Derek D. Cissell
- Department of Surgical and Radiological Sciences, University of California Davis, Davis, CA 95616, USA; (D.D.C.); (P.J.D.)
| | - Peter J. Dickinson
- Department of Surgical and Radiological Sciences, University of California Davis, Davis, CA 95616, USA; (D.D.C.); (P.J.D.)
| | - G. Diane Shelton
- Department of Pathology, University of California San Diego, La Jolla, CA 92093, USA;
| | | | - K. Michael Gibson
- College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA 99202, USA;
| | | | - Florian König
- Fachtierarzt fur Kleintiere, Am Berggewann 13, 65199 Wiesbaden, Germany;
| | - Thomas J. Van Winkle
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Dennis O’Brien
- College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA;
| | - B. Roos
- Department of Clinical Chemistry, VU University Medical Center, 1081 HV Amsterdam, The Netherlands; (E.S.); (B.R.)
| | - Kaspar Matiasek
- Clinical and Comparative Neuropathology, Ludwig-Maximilians-Universitaet München, 80539 Munchen, Germany;
| | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland; (A.L.); (V.J.); (C.D.)
| | - Cord Drögemüller
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland; (A.L.); (V.J.); (C.D.)
| | - Tamer A. Mansour
- Department of Population Health and Reproduction, University of California Davis, Davis, CA 95616, USA; (M.A.); (E.A.B.); (T.A.M.); (C.T.B.)
- Department of Clinical Pathology, School of Medicine, Mansoura University, Mansoura 35516, Egypt
| | - C. Titus Brown
- Department of Population Health and Reproduction, University of California Davis, Davis, CA 95616, USA; (M.A.); (E.A.B.); (T.A.M.); (C.T.B.)
| | - Danika L. Bannasch
- Department of Population Health and Reproduction, University of California Davis, Davis, CA 95616, USA; (M.A.); (E.A.B.); (T.A.M.); (C.T.B.)
- Correspondence: (K.M.V.); (D.L.B.)
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8
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Brown MN, Walters DC, Schmidt MA, Hill J, McConnell A, Jansen EEW, Salomons GS, Arning E, Bottiglieri T, Gibson KM, Roullet JB. Maternal glutamine supplementation in murine succinic semialdehyde dehydrogenase deficiency, a disorder of γ-aminobutyric acid metabolism. J Inherit Metab Dis 2019; 42:1030-1039. [PMID: 31032972 DOI: 10.1002/jimd.12107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/29/2019] [Accepted: 04/25/2019] [Indexed: 11/09/2022]
Abstract
Murine succinic semialdehyde dehydrogenase deficiency (SSADHD) manifests with high concentrations of γ-aminobutyric acid (GABA) and γ-hydroxybutyrate (GHB) and low glutamine in the brain. To understand the pathogenic contribution of central glutamine deficiency, we exposed aldh5a1-/- (SSADHD) mice and their genetic controls (aldh5a1+/+ ) to either a 4% (w/w) glutamine-containing diet or a glutamine-free diet from conception until postnatal day 30. Endpoints included brain, liver and blood amino acids, brain GHB, ataxia scores, and open field testing. Glutamine supplementation did not improve aldh5a1-/- brain glutamine deficiency nor brain GABA and GHB. It decreased brain glutamate but did not change the ratio of excitatory (glutamate) to inhibitory (GABA) neurotransmitters. In contrast, glutamine supplementation significantly increased brain arginine (30% for aldh5a1+/+ and 18% for aldh5a1-/- mice), and leucine (12% and 18%). Glutamine deficiency was confirmed in the liver. The test diet increased hepatic glutamate in both genotypes, decreased glutamine in aldh5a1+/+ but not in aldh5a1-/- , but had no effect on GABA. Dried bloodspot analyses showed significantly elevated GABA in mutants (approximately 800% above controls) and decreased glutamate (approximately 25%), but no glutamine difference with controls. Glutamine supplementation did not impact blood GABA but significantly increased glutamine and glutamate in both genotypes indicating systemic exposure to dietary glutamine. Ataxia and pronounced hyperactivity were observed in aldh5a1-/- mice but remained unchanged by the diet intervention. The study suggests that glutamine supplementation improves peripheral but not central glutamine deficiency in experimental SSADHD. Future studies are needed to fully understand the pathogenic role of brain glutamine deficiency in SSADHD.
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Affiliation(s)
- 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
| | - Michelle A Schmidt
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington
| | | | | | - Erwin E W Jansen
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center & Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Gajja S Salomons
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center & Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Erland Arning
- Baylor Scott and White Research Institute, Institute of Metabolic Disease, Dallas, Texas
| | - Teodoro Bottiglieri
- Baylor Scott and White Research Institute, Institute of Metabolic Disease, Dallas, Texas
| | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, Washington
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9
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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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10
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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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Harris SR, Zhang GF, Sadhukhan S, Wang H, Shi C, Puchowicz MA, Anderson VE, Salomon RG, Tochtrop GP, Brunengraber H. Metabolomics and mass isotopomer analysis as a strategy for pathway discovery: pyrrolyl and cyclopentenyl derivatives of the pro-drug of abuse, levulinate. Chem Res Toxicol 2012; 26:213-20. [PMID: 23171137 DOI: 10.1021/tx3003643] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We recently reported that levulinate (4-ketopentanoate) is converted in the liver to 4-hydroxypentanoate, a drug of abuse, and that the formation of 4-hydroxypentanoate is stimulated by ethanol oxidation. We also identified 3 parallel β-oxidation pathways by which levulinate and 4-hydroxypentanoate are catabolized to propionyl-CoA and acetyl-CoA. We now report that levulinate forms three seven-carbon cyclical CoA esters by processes starting with the elongation of levulinyl-CoA by acetyl-CoA to 3,6-diketoheptanoyl-CoA. The latter γ-diketo CoA ester undergoes two parallel cyclization processes. One process yields a mixture of tautomers, i.e., cyclopentenyl- and cyclopentadienyl-acyl-CoAs. The second cyclization process yields a methyl-pyrrolyl-acetyl-CoA containing a nitrogen atom derived from the ε-nitrogen of lysine but without carbons from lysine. The cyclic CoA esters were identified in rat livers perfused with levulinate and in livers and brains from rats gavaged with calcium levulinate ± ethanol. Lastly, 3,6-diketoheptanoyl-CoA, like 2,5-diketohexane, pyrrolates free lysine and, presumably, lysine residues from proteins. This may represent a new pathway for protein pyrrolation. The cyclic CoA esters and related pyrrolation processes may play a role in the toxic effects of 4-hydroxypentanoate.
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Affiliation(s)
- Stephanie R Harris
- Department of Nutrition, Case Western Reserve University, Cleveland, OH 44106, USA
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12
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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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Harris SR, Zhang GF, Sadhukhan S, Murphy AM, Tomcik KA, Vazquez EJ, Anderson VE, Tochtrop GP, Brunengraber H. Metabolism of levulinate in perfused rat livers and live rats: conversion to the drug of abuse 4-hydroxypentanoate. J Biol Chem 2010; 286:5895-904. [PMID: 21126961 DOI: 10.1074/jbc.m110.196808] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Calcium levulinate (4-ketopentanoate) is used as an oral and parenteral source of calcium. We hypothesized that levulinate is converted in the liver to 4-hydroxypentanoate, a new drug of abuse, and that this conversion is accelerated by ethanol oxidation. We confirmed these hypotheses in live rats, perfused rat livers, and liver subcellular preparations. Levulinate is reduced to (R)-4-hydroxypentanoate by a cytosolic and a mitochondrial dehydrogenase, which are NADPH- and NADH-dependent, respectively. A mitochondrial dehydrogenase or racemase system also forms (S)-4-hydroxypentanoate. In livers perfused with [(13)C(5)]levulinate, there was substantial CoA trapping in levulinyl-CoA, 4-hydroxypentanoyl-CoA, and 4-phosphopentanoyl-CoA. This CoA trapping was increased by ethanol, with a 6-fold increase in the concentration of 4-phosphopentanoyl-CoA. Levulinate is catabolized by 3 parallel pathways to propionyl-CoA, acetyl-CoA, and lactate. Most intermediates of the 3 pathways were identified by mass isotopomer analysis and metabolomics. The production of 4-hydroxypentanoate from levulinate and its stimulation by ethanol is a potential public health concern.
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Affiliation(s)
- Stephanie R Harris
- Department of Nutrition, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Vardya I, Drasbek KR, Gibson KM, Jensen K. Plasticity of postsynaptic, but not presynaptic, GABAB receptors in SSADH deficient mice. Exp Neurol 2010; 225:114-22. [PMID: 20570675 DOI: 10.1016/j.expneurol.2010.05.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 04/26/2010] [Accepted: 05/27/2010] [Indexed: 12/28/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH) deficiency is an autosomal-recessively inherited disorder of gamma-aminobutyrate (GABA) catabolism characterized by ataxia and epilepsy. Since SSADH is responsible for GABA break-down downstream of GABA transaminase, patients manifest high extracellular levels of GABA, as well as the GABA(B) receptor (GABA(B)R) agonist gamma-hydroxybutyrate (GHB). SSADH knockout (KO) mice display absence seizures, which progress into lethal tonic-clonic seizures at around 3weeks of age. It is hypothesized that desensitization of GABA(B)Rs plays an important role in the disease, although detailed studies of pre- and postsynaptic GABA(B)Rs are not available. We performed patch-clamp recordings from layer 2/3 pyramidal neurons in neocortical brain slices of wild-type (WT) and SSADH KO mice. Electrical stimulation of GABAergic fibers during wash in of the GABA(B)R agonist baclofen revealed no difference in presynaptic GABA(B)R mediated inhibition of GABA release between WT and SSADH KO mice. In contrast, a significant decrease in postsynaptic baclofen-induced potassium currents was seen in SSADH KO mice. This reduction was unlikely to be caused by accumulation of potassium, GABA or GHB in the brain slices, or an altered expression of regulators of G-protein signaling (RGS) proteins. Finally, adenosine-induced potassium currents were also reduced in SSADH KO mice, which could suggest heterologous desensitization of the G-protein dependent effectors, leading to a reduction in G-protein coupled inwardly rectifying potassium (GIRK) channel responses. Our findings indicate that high GABA and GHB levels desensitize postsynaptic, but not certain presynaptic, GABA(B)Rs, promoting a decrease in GIRK channel function. These changes could contribute to the development of seizures in SSADH KO mice and potentially also in affected patients.
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Affiliation(s)
- Irina Vardya
- Synaptic Physiology Laboratory, Department of Physiology and Biophysics, Aarhus University, Denmark
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15
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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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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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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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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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20
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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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Abstract
The investigation of rare neurogenetic diseases is an example of how a translational science approach may lead to the delineation of complex genetic and biochemical pathways. Thisprocess comprises several intellectual stages. The first step involves the astute identification and clinical description of the unique phenotype, which may lead to obvious pathways or may reveal novel or unexpected mechanisms. As similar patients are identified, the establishment of databases detailing the clinical phenotype may serve to provide clues as to the genetic and biochemical characterization, and identification of the genetic mutation based on patient samples and animal or cellular models. Lastly, attempts to develop and apply therapies based on what has been learned about the biochemical and molecular bases of the disease enables intervention on the individual patient level. Several stages of discovery may overlap or be investigated simultaneously. As examples, this review discusses how this process of investigation has enabled progress in the delineation of several genetic and neurogenetic disorders, including Progeria syndrome, neurodegenerative diseases, muscular dystrophy, Rett syndrome and neurotransmitter disorders. This review attempts to summarize the transition from the bedside-to-bench-to-bedside as a model of bringing such discoveries into the clinical arena, and in doing so addresses the issues that may enhance, or complicate, such a path of discovery, as well as the impact such advances in genetics and genomics may have on the practice of clinical medicine and the role of the physician.
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Affiliation(s)
- Andrea Gropman
- Georgetown University, Department of Pediatrics, Washington, DC 20007, USA. Current address: Department of Neurology, Children’s National Medical Center, George Washington University School of Medicine, Washington, DC 20010, USA
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Blasi P, Palmerio F, Caldarola S, Rizzo C, Carrozzo R, Gibson KM, Novelletto A, Deodato F, Cappa M, Dioni-Vici C, Malaspina P. Succinic semialdehyde dehydrogenase deficiency: clinical, biochemical and molecular characterization of a new patient with severe phenotype and a novel mutation. Clin Genet 2006; 69:294-6. [PMID: 16542398 DOI: 10.1111/j.1399-0004.2006.00579.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Jansen EEW, Verhoeven NM, Jakobs C, Schulze A, Senephansiri H, Gupta M, Snead OC, Gibson KM. Increased guanidino species in murine and human succinate semialdehyde dehydrogenase (SSADH) deficiency. Biochim Biophys Acta Mol Basis Dis 2006; 1762:494-8. [PMID: 16504488 DOI: 10.1016/j.bbadis.2006.01.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Revised: 01/18/2006] [Accepted: 01/19/2006] [Indexed: 11/23/2022]
Abstract
Mice with targeted deletion of the GABA-degradative enzyme succinate semialdehyde dehydrogenase (SSADH; Aldh5a1; OMIM 271,980) manifest globally elevated GABA and regionally decreased arginine in brain extracts. We examined the hypothesis that arginine-glycine amidinotransferase catalyzed the formation of guanidinobutyrate (GB) from increased GABA by quantifying guanidinoacetate (GA), guanidinopropionate (GP) and GB in brain extracts employing stable isotope dilution gas chromatographic-mass spectrometry. GA and GB were up to 4- and 22-fold elevated, respectively, in total and regional (cerebellum, hippocampus, cortex) brain extracts derived from SSADH(-/-) mice. Corresponding analyses of urine and cerebrospinal fluid derived from SSADH-deficient patients revealed significant (P<0.05) elevations of GA and GB in urine, as well as GB levels in CSF. These data suggest that GB may be an additional marker of SSADH deficiency, implicate additional pathways of pathophysiology, and identify the second instance of elevated GB in a human inborn error of metabolism.
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Affiliation(s)
- Erwin E W Jansen
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam, The Netherlands
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