51
|
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.
Collapse
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
| |
Collapse
|
52
|
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.
Collapse
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
| |
Collapse
|
53
|
Galvez Rojas RL, Ahn IY, Suárez Mantilla B, Sant'Anna C, Pral EMF, Silber AM. The Uptake of GABA in Trypanosoma cruzi. J Eukaryot Microbiol 2015; 62:629-36. [PMID: 25851259 DOI: 10.1111/jeu.12219] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/12/2015] [Accepted: 02/02/2015] [Indexed: 12/27/2022]
Abstract
Gamma aminobutyric acid (GABA) is widely known as a neurotransmitter and signal transduction molecule found in vertebrates, plants, and some protozoan organisms. However, the presence of GABA and its role in trypanosomatids is unknown. Here, we report the presence of intracellular GABA and the biochemical characterization of its uptake in Trypanosoma cruzi, the etiological agent of Chagas' disease. Kinetic parameters indicated that GABA is taken up by a single transport system in pathogenic and nonpathogenic forms. Temperature dependence assays showed a profile similar to glutamate transport, but the effect of extracellular cations Na(+) , K(+) , and H(+) on GABA uptake differed, suggesting a different uptake mechanism. In contrast to reports for other amino acid transporters in T. cruzi, GABA uptake was Na(+) dependent and increased with pH, with a maximum activity at pH 8.5. The sensitivity to oligomycin showed that GABA uptake is dependent on ATP synthesis. These data point to a secondary active Na(+) /GABA symporter energized by Na(+) -exporting ATPase. Finally, we show that GABA occurs in the parasite's cytoplasm under normal culture conditions, indicating that it is regularly taken up from the culture medium or synthesized through an still undescribed metabolic pathway.
Collapse
Affiliation(s)
- Robert L Galvez Rojas
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Il-Young Ahn
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Brian Suárez Mantilla
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Celso Sant'Anna
- Instituto Nacional de Metrologia (INMetro), Rio de Janeiro, Brazil
| | | | - Ariel Mariano Silber
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| |
Collapse
|
54
|
Vogel KR, Ainslie GR, Jansen EEW, Salomons GS, Gibson KM. Torin 1 partially corrects vigabatrin-induced mitochondrial increase in mouse. Ann Clin Transl Neurol 2015; 2:699-706. [PMID: 26125044 PMCID: PMC4479529 DOI: 10.1002/acn3.200] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 03/09/2015] [Accepted: 03/11/2015] [Indexed: 12/30/2022] Open
Abstract
Recent findings in mice with targeted deletion of the GABA-metabolic enzyme succinic semialdehyde dehydrogenase revealed a new role for supraphysiological GABA (4-aminobutyric acid) in the activation of the mechanistic target of rapamycin (mTOR) that results in disruption of endogenous mitophagy. Employing biochemical and electron microscopic methodology, we examined the hypothesis that similar outcomes would be observed during intervention with vigabatrin, whose antiepileptic capacity hinges on central nervous system GABA elevation. Vigabatrin intervention was associated with significantly enhanced mitochondrial numbers and areas in normal mice that could be selectively normalized with the rapalog and mechanistic target of rapamycin inhibitor, Torin 1. Moreover, short-term administration of vigabatrin induced apoptosis and enhanced phosphorylation of mechanistic target of rapamycin Ser 2448 in liver. Our results provide new insight into adverse outcomes associated with vigabatrin intervention, and the first evidence that its administration is associated with increased mitochondrial number in central and peripheral tissues that may associate with mechanistic target of rapamycin function and enhanced cell death.
Collapse
Affiliation(s)
- Kara R Vogel
- Section of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University Spokane, Washington
| | - Garrett R Ainslie
- Section of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University Spokane, Washington
| | - Erwin E W Jansen
- Metabolic Unit, Department of Clinical Chemistry, VU University Medical Center Neuroscience Campus, Amsterdam, The Netherlands
| | - Gajja S Salomons
- Metabolic Unit, Department of Clinical Chemistry, VU University Medical Center Neuroscience Campus, Amsterdam, The Netherlands
| | - K Michael Gibson
- Section of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University Spokane, Washington
| |
Collapse
|
55
|
Chun PT, McPherson RJ, Marney LC, Zangeneh SZ, Parsons BA, Shojaie A, Synovec RE, Juul SE. Serial plasma metabolites following hypoxic-ischemic encephalopathy in a nonhuman primate model. Dev Neurosci 2015; 37:161-71. [PMID: 25765047 DOI: 10.1159/000370147] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 11/25/2014] [Indexed: 12/27/2022] Open
Abstract
Biomarkers that indicate the severity of hypoxic-ischemic brain injury and response to treatment and that predict neurodevelopmental outcomes are urgently needed to improve the care of affected neonates. We hypothesize that sequentially obtained plasma metabolomes will provide indicators of brain injury and repair, allowing for the prediction of neurodevelopmental outcomes. A total of 33 Macaca nemestrina underwent 0, 15 or 18 min of in utero umbilical cord occlusion (UCO) to induce hypoxic-ischemic encephalopathy and were then delivered by hysterotomy, resuscitated and stabilized. Serial blood samples were obtained at baseline (cord blood) and at 0.1, 24, 48, and 72 h of age. Treatment groups included nonasphyxiated controls (n = 7), untreated UCO (n = 11), UCO + hypothermia (HT; n = 6), and UCO + HT + erythropoietin (n = 9). Metabolites were extracted and analyzed using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry and quantified by PARAFAC (parallel factor analysis). Using nontargeted discovery-based methods, we identified 63 metabolites as potential biomarkers. The changes in metabolite concentrations were characterized and compared between treatment groups. Further comparison determined that 8 metabolites (arachidonic acid, butanoic acid, citric acid, fumaric acid, lactate, malate, propanoic acid, and succinic acid) correlated with early and/or long-term neurodevelopmental outcomes. The combined outcomes of death or cerebral palsy correlated with citric acid, fumaric acid, lactate, and propanoic acid. This change in circulating metabolome after UCO may reflect cellular metabolism and biochemical changes in response to the severity of brain injury and have potential to predict neurodevelopmental outcomes.
Collapse
|
56
|
Maiese K. Cutting through the complexities of mTOR for the treatment of stroke. Curr Neurovasc Res 2014; 11:177-86. [PMID: 24712647 DOI: 10.2174/1567202611666140408104831] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/17/2014] [Accepted: 03/19/2014] [Indexed: 01/06/2023]
Abstract
On a global basis, at least 15 million individuals suffer some form of a stroke every year. Of these individuals, approximately 800,000 of these cerebrovascular events occur in the United States (US) alone. The incidence of stroke in the US has declined from the third leading cause of death to the fourth, a result that can be attributed to multiple factors that include improved vascular disease management, reduced tobacco use, and more rapid time to treatment in patients that are clinically appropriate to receive recombinant tissue plasminogen activator. However, treatment strategies for the majority of stroke patients are extremely limited and represent a critical void for care. A number of new therapeutic considerations for stroke are under consideration, but it is the mammalian target of rapamycin (mTOR) that is receiving intense focus as a potential new target for cerebrovascular disease. As part of the phosphoinositide 3-kinase (PI 3-K) and protein kinase B (Akt) cascade, mTOR is an essential component of mTOR Complex 1 (mTORC1) and mTOR Complex 2 (mTORC2) to govern cell death involving apoptosis, autophagy, and necroptosis, cellular metabolism, and gene transcription. Vital for the consideration of new therapeutic strategies for stroke is the ability to understand how the intricate and complex pathways of mTOR signaling sometimes lead to disparate clinical outcomes.
Collapse
Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, Newark, New Jersey 07101, USA.
| |
Collapse
|
57
|
Sanayama Y, Matsumoto A, Shimojo N, Kohno Y, Nakaya H. Phenylalanine sensitive K562-D cells for the analysis of the biochemical impact of excess amino acid. Sci Rep 2014; 4:6941. [PMID: 25373594 PMCID: PMC4221789 DOI: 10.1038/srep06941] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/20/2014] [Indexed: 12/31/2022] Open
Abstract
Although it is recognized that the abnormal accumulation of amino acid is a cause of the symptoms in metabolic disease such as phenylketonuria (PKU), the relationship between disease severity and serum amino acid levels is not well understood due to the lack of experimental model. Here, we present a novel in vitro cellular model using K562-D cells that proliferate slowly in the presence of excessive amount of phenylalanine within the clinically observed range, but not phenylpyruvate. The increased expression of the L-type amino acid transporter (LAT2) and its adapter protein 4F2 heavy chain appeared to be responsible for the higher sensitivity to phenylalanine in K562-D cells. Supplementation with valine over phenylalanine effectively restored cell proliferation, although other amino acids did not improve K562-D cell proliferation over phenylalanine. Biochemical analysis revealed mammalian target of rapamycin complex (mTORC) as a terminal target of phenylalanine in K562-D cell proliferation, and supplementation of valine restored mTORC1 activity. Our results show that K562-D cell can be a potent tool for the investigation of PKU at the molecular level and to explore new therapeutic approaches to the disease.
Collapse
Affiliation(s)
- Yoshitami Sanayama
- 1] Department of Pharmacology, Graduate School of Medicine, Chiba University, Chiba [2] Department of Pediatrics, National Hospital Organization, Shimoshizu Hospital, Chiba
| | - Akio Matsumoto
- Department of Pharmacology, Graduate School of Medicine, Chiba University, Chiba
| | - Naoki Shimojo
- Department of Pediatrics, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Yoichi Kohno
- Department of Pediatrics, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Haruaki Nakaya
- Department of Pharmacology, Graduate School of Medicine, Chiba University, Chiba
| |
Collapse
|