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Leipnitz G, da Rosa JS, Wajner M. The Role of Excitotoxicity, Oxidative Stress and Bioenergetics Disruption in the Neuropathology of Nonketotic Hyperglycinemia. Neurotox Res 2024; 42:32. [PMID: 38949693 DOI: 10.1007/s12640-024-00711-5] [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: 01/16/2024] [Revised: 06/11/2024] [Accepted: 06/20/2024] [Indexed: 07/02/2024]
Abstract
Nonketotic hyperglycinemia (NKH) is an inherited disorder of amino acid metabolism biochemically characterized by the accumulation of glycine (Gly) predominantly in the brain. Affected patients usually manifest with neurological symptoms including hypotonia, seizures, epilepsy, lethargy, and coma, the pathophysiology of which is still not completely understood. Treatment is limited and based on lowering Gly levels aiming to reduce overstimulation of N-methyl-D-aspartate (NMDA) receptors. Mounting in vitro and in vivo animal and human evidence have recently suggested that excitotoxicity, oxidative stress, and bioenergetics disruption induced by Gly are relevant mechanisms involved in the neuropathology of NKH. This brief review gives emphasis to the deleterious effects of Gly in the brain of patients and animal models of NKH that may offer perspectives for the development of novel adjuvant treatments for this disorder.
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Affiliation(s)
- Guilhian Leipnitz
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre, RS, 90035-003, Brazil.
- Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre, RS, CEP 90035-003, Brazil.
| | - Jaqueline Santana da Rosa
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre, RS, 90035-003, Brazil
| | - Moacir Wajner
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre, RS, 90035-003, Brazil
- Programa de Pós-Graduação em Ciências Biológicas: Fisiologia, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre, RS, CEP 90035-003, Brazil
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos, 2350, Porto Alegre, 90035-903, RS, Brazil
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Parmeggiani B, Signori MF, Cecatto C, Frusciante MR, Marcuzzo MB, Souza DG, Ribeiro RT, Seminotti B, Gomes de Souza DO, Ribeiro CAJ, Wajner M, Leipnitz G. Glycine disrupts myelin, glutamatergic neurotransmission, and redox homeostasis in a neonatal model for non ketotic hyperglycinemia. Biochimie 2024; 219:21-32. [PMID: 37541567 DOI: 10.1016/j.biochi.2023.07.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 06/26/2023] [Accepted: 07/30/2023] [Indexed: 08/06/2023]
Abstract
Non ketotic hyperglycinemia (NKH) is an inborn error of glycine metabolism caused by mutations in the genes encoding glycine cleavage system proteins. Classic NKH has a neonatal onset, and patients present with severe neurodegeneration. Although glycine accumulation has been implicated in NKH pathophysiology, the exact mechanisms underlying the neurological damage and white matter alterations remain unclear. We investigated the effects of glycine in the brain of neonatal rats and MO3.13 oligodendroglial cells. Glycine decreased myelin basic protein (MBP) and myelin-associated glycoprotein (MAG) in the corpus callosum and striatum of rats on post-natal day (PND) 15. Glycine also reduced neuroglycan 2 (NG2) and N-methyl-d-aspartate receptor subunit 1 (NR1) in the cerebral cortex and striatum on PND15. Moreover, glycine reduced striatal glutamate aspartate transporter 1 (GLAST) content and neuronal nucleus (NeuN), and increased glial fibrillary acidic protein (GFAP) on PND15. Glycine also increased DCFH oxidation and malondialdehyde levels and decreased GSH concentrations in the cerebral cortex and striatum on PND6, but not on PND15. Glycine further reduced viability but did not alter DCFH oxidation and GSH levels in MO3.13 cells after 48- and 72-h incubation. These data indicate that impairment of myelin structure and glutamatergic system and induction of oxidative stress are involved in the neuropathophysiology of NKH.
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Affiliation(s)
- Belisa Parmeggiani
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
| | - Marian Flores Signori
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Cristiane Cecatto
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Marina Rocha Frusciante
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Manuela Bianchin Marcuzzo
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Débora Guerini Souza
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Brain Institute of Rio Grande do Sul, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Rafael Teixeira Ribeiro
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Bianca Seminotti
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Diogo Onofre Gomes de Souza
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - César Augusto João Ribeiro
- Natural and Humanities Sciences Center, Universidade Federal do ABC, São Bernardo do Campo, SP, 09606-070, Brazil
| | - Moacir Wajner
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Serviço de Genética Médica do Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Guilhian Leipnitz
- Programa de Pós-Graduação em Ciências Biológicas - Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Weaver NE, Healy A, Wingert RA. gldc Is Essential for Renal Progenitor Patterning during Kidney Development. Biomedicines 2022; 10:biomedicines10123220. [PMID: 36551976 PMCID: PMC9776136 DOI: 10.3390/biomedicines10123220] [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: 11/05/2022] [Revised: 12/04/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
The glycine cleavage system (GCS) is a complex located on the mitochondrial membrane that is responsible for regulating glycine levels and contributing one-carbon units to folate metabolism. Congenital mutations in GCS components, such as glycine decarboxylase (gldc), cause an elevation in glycine levels and the rare disease, nonketotic hyperglycinemia (NKH). NKH patients suffer from pleiotropic symptoms including seizures, lethargy, mental retardation, and early death. Therefore, it is imperative to fully elucidate the pathological effects of gldc dysfunction and glycine accumulation during development. Here, we describe a zebrafish model of gldc deficiency that recapitulates phenotypes seen in humans and mice. gldc deficient embryos displayed impaired fluid homeostasis suggesting renal abnormalities, as well as aberrant craniofacial morphology and neural development defects. Whole mount in situ hybridization (WISH) revealed that gldc transcripts were highly expressed in the embryonic kidney, as seen in mouse and human repository data, and that formation of several nephron segments was disrupted in gldc deficient embryos, including proximal and distal tubule populations. These kidney defects were caused by alterations in renal progenitor populations, revealing that the proper function of Gldc is essential for the patterning of this organ. Additionally, further analysis of the urogenital tract revealed altered collecting duct and cloaca morphology in gldc deficient embryos. Finally, to gain insight into the molecular mechanisms underlying these disruptions, we examined the effects of exogenous glycine treatment and observed analogous renal and cloacal defects. Taken together, these studies indicate for the first time that gldc function serves an essential role in regulating renal progenitor development by modulating glycine levels.
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Kuseyri Hübschmann O, Palacios NAJ, Olivella M, Guder P, Zafeiriou DI, Horvath G, Kulhánek J, Pearson TS, Kuster A, Cortès-Saladelafont E, Ibáñez S, García-Jiménez MC, Honzík T, Santer R, Jeltsch K, Garbade SF, Hoffmann GF, Opladen T, García-Cazorla Á. An integrative approach to predict severity in nonketotic hyperglycinemia. Ann Neurol 2022; 92:292-303. [PMID: 35616651 DOI: 10.1002/ana.26423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 05/19/2022] [Accepted: 05/23/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Glycine encephalopathy, also known as nonketotic hyperglycinemia (NKH), is an inherited neurometabolic disorder with variable clinical course and severity, ranging from infantile epileptic encephalopathy to psychiatric disorders. A precise phenotypic characterization and an evaluation of predictive approaches are needed. METHODS Longitudinal clinical and biochemical data of 25 individuals with NKH from the patient registry of International Working Group on Neurotransmitter related Disorders were studied with in silico analyses, pathogenicity scores and molecular modeling of GLDC and AMT variants. RESULTS Symptom onset (p<0· 01) and diagnosis occur earlier in life in severe NKH (p<0· 01). Presenting symptoms affect the age at diagnosis. Psychiatric problems occur predominantly in attenuated NKH. Onset-age ≥3 months (66% specificity, 100% sensitivity, AUC = 0·87) and cerebrospinal fluid (CSF)/plasma glycine ratio ≤0· 09 (57% specificity, 100% sensitivity, AUC = 0·88) are sensitive indicators for attenuated NKH while CSF glycine concentration ≥116· 5 μmol/L (100% specificity, 93% sensitivity, AUC = 0·97) and CSF/plasma glycine ratio ≥0· 15 (100% specificity, 64% sensitivity, AUC = 0·88) are specific for severe forms. A ratio threshold of 0· 128 discriminates the overlapping range. We present ten new GLDC variants. Two mild variants resulted in attenuated, while two severe variants or one mild and one severe variant lead to severe phenotype. Based on clinical, biochemical and genetic parameter we propose a severity prediction model. INTERPRETATION This study widens the phenotypic spectrum of attenuated NKH and expands the number of pathogenic variants. The multiparametric approach provides a promising tool to predict disease severity, helping to improve clinical management strategies. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Oya Kuseyri Hübschmann
- University Children's Hospital Heidelberg, Division of Child Neurology and Metabolic Disorders, Heidelberg, Germany
| | - Natalia Alexandra Julia Palacios
- Inborn errors of metabolism Unit, Department of Neurology, Institut de Recerca Sant Joan de Déu, CIBERER-ISCIII and MetabERN, Barcelona, Spain
| | - Mireia Olivella
- Bioinformatics and Medical Statistics Group. Facultat de Ciències i Tecnologia. Universitat de Vic - Universitat Central de Catalunya (UVic-UCC), Vic, Barcelona, Spain
| | - Philipp Guder
- Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Dimitrios I Zafeiriou
- First Department of Pediatrics Aristotle University of Thessaloniki Egnatia St. 106 54622, Thessaloniki, Greece
| | - Gabriella Horvath
- University of British Columbia, Department of Pediatrics, Division of Biochemical Genetics, BC Children's Hospital, Vancouver, BC, Canada
| | - Jan Kulhánek
- Department of Pediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Toni S Pearson
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alice Kuster
- Department of Neurometabolism and Metabolic Disorders, University Hospital of Nantes, Nantes, France
| | - Elisenda Cortès-Saladelafont
- Inborn errors of metabolism Unit, Department of Neurology, Institut de Recerca Sant Joan de Déu, CIBERER-ISCIII and MetabERN, Barcelona, Spain.,Inborn Errors of Metabolism and Child Neurology Unit, Department of Pediatrics, Hospital Germans Trias i Pujol, Badalona and Faculty of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Salvador Ibáñez
- Department of Pediatric Neurology, Hospital Virgen de la Arrixaca, Murcia, Spain
| | | | - Tomáš Honzík
- Department of Pediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - René Santer
- Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Kathrin Jeltsch
- University Children's Hospital Heidelberg, Division of Child Neurology and Metabolic Disorders, Heidelberg, Germany
| | - Sven F Garbade
- University Children's Hospital Heidelberg, Dietmar-Hopp Metabolic Center, Heidelberg, Germany
| | - Georg F Hoffmann
- University Children's Hospital Heidelberg, Division of Child Neurology and Metabolic Disorders, Heidelberg, Germany
| | - Thomas Opladen
- University Children's Hospital Heidelberg, Division of Child Neurology and Metabolic Disorders, Heidelberg, Germany
| | - Ángeles García-Cazorla
- Inborn errors of metabolism Unit, Department of Neurology, Institut de Recerca Sant Joan de Déu, CIBERER-ISCIII and MetabERN, Barcelona, Spain
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5
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The Role of Oxidative Stress and Bioenergetic Dysfunction in Sulfite Oxidase Deficiency: Insights from Animal Models. Neurotox Res 2018; 35:484-494. [DOI: 10.1007/s12640-018-9986-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/13/2018] [Accepted: 11/26/2018] [Indexed: 02/07/2023]
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Grings M, Parmeggiani B, Moura AP, de Moura Alvorcem L, Wyse ATS, Wajner M, Leipnitz G. Evidence that Thiosulfate Inhibits Creatine Kinase Activity in Rat Striatum via Thiol Group Oxidation. Neurotox Res 2018; 34:693-705. [DOI: 10.1007/s12640-018-9934-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 07/06/2018] [Accepted: 07/17/2018] [Indexed: 12/13/2022]
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Bezafibrate Prevents Glycine-Induced Increase of Antioxidant Enzyme Activities in Rat Striatum. Mol Neurobiol 2018; 56:29-38. [DOI: 10.1007/s12035-018-1074-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 04/10/2018] [Indexed: 02/03/2023]
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8
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Souza DG, Bellaver B, Terra SR, Guma FCR, Souza DO, Quincozes‐Santos A. In Vitro Adult Astrocytes are Derived From Mature Cells and Reproduce in Vivo Redox Profile. J Cell Biochem 2017; 118:3111-3118. [DOI: 10.1002/jcb.26028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 04/03/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Débora Guerini Souza
- Programa de Pós‐Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da SaúdeUniversidade Federal do Rio Grande do SulRio Grande do SulBrazil
| | - Bruna Bellaver
- Programa de Pós‐Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da SaúdeUniversidade Federal do Rio Grande do SulRio Grande do SulBrazil
| | - Silvia Resende Terra
- Programa de Pós‐Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da SaúdeUniversidade Federal do Rio Grande do SulRio Grande do SulBrazil
| | - Fatima Costa Rodrigues Guma
- Programa de Pós‐Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da SaúdeUniversidade Federal do Rio Grande do SulRio Grande do SulBrazil
- Departamento de Bioquímica, Instituto de Ciências Básicas da SaúdeUniversidade Federal do Rio Grande do SulRio Grande do SulBrazil
| | - Diogo Onofre Souza
- Programa de Pós‐Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da SaúdeUniversidade Federal do Rio Grande do SulRio Grande do SulBrazil
- Departamento de Bioquímica, Instituto de Ciências Básicas da SaúdeUniversidade Federal do Rio Grande do SulRio Grande do SulBrazil
| | - André Quincozes‐Santos
- Programa de Pós‐Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da SaúdeUniversidade Federal do Rio Grande do SulRio Grande do SulBrazil
- Departamento de Bioquímica, Instituto de Ciências Básicas da SaúdeUniversidade Federal do Rio Grande do SulRio Grande do SulBrazil
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Moura AP, Parmeggiani B, Gasparotto J, Grings M, Fernandez Cardoso GM, Seminotti B, Moreira JCF, Gelain DP, Wajner M, Leipnitz G. Glycine Administration Alters MAPK Signaling Pathways and Causes Neuronal Damage in Rat Brain: Putative Mechanisms Involved in the Neurological Dysfunction in Nonketotic Hyperglycinemia. Mol Neurobiol 2017; 55:741-750. [PMID: 28050793 DOI: 10.1007/s12035-016-0319-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 11/21/2016] [Indexed: 12/14/2022]
Abstract
High glycine (GLY) levels have been suggested to induce neurotoxic effects in the central nervous system of patients with nonketotic hyperglycinemia (NKH). Since the mechanisms involved in the neuropathophysiology of NKH are not totally established, we evaluated the effect of a single intracerebroventricular administration of GLY on the content of proteins involved in neuronal damage and inflammatory response, as well as on the phosphorylation of the MAPK p38, ERK1/2, and JNK in rat striatum and cerebral cortex. We also examined glial fibrillary acidic protein (GFAP) staining, a marker of glial reactivity. The parameters were analyzed 30 min or 24 h after GLY administration. GLY decreased Tau phosphorylation in striatum and cerebral cortex 30 min and 24 h after its administration. On the other hand, synaptophysin levels were decreased in striatum at 30 min and in cerebral cortex at 24 h after GLY injection. GLY also decreased the phosphorylation of p38, ERK1/2, and JNK 30 min after its administration in both brain structures. Moreover, GLY-induced decrease of p38 phosphorylation in striatum was attenuated by N-methyl-D-aspartate receptor antagonist MK-801. In contrast, synuclein, NF-κB, iκB, inducible nitric oxide synthase and nitrotyrosine content, and GFAP immunostaining were not altered by GLY infusion. It may be presumed that the decreased phosphorylation of MAPK associated with alterations of markers of neuronal injury induced by GLY may contribute to the neurological dysfunction observed in NKH.
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Affiliation(s)
- Alana Pimentel Moura
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Belisa Parmeggiani
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Juciano Gasparotto
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Mateus Grings
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Gabriela Miranda Fernandez Cardoso
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Bianca Seminotti
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - José Cláudio Fonseca Moreira
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal de Rio Grande do Sul, Rua Ramiro Barcelos N° 2600 - Attached, Porto Alegre, RS, CEP: 90035-003, Brazil
| | - Daniel Pens Gelain
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal de Rio Grande do Sul, Rua Ramiro Barcelos N° 2600 - Attached, Porto Alegre, RS, CEP: 90035-003, Brazil
| | - Moacir Wajner
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal de Rio Grande do Sul, Rua Ramiro Barcelos N° 2600 - Attached, Porto Alegre, RS, CEP: 90035-003, Brazil
- Serviço de Genética Médica do Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Guilhian Leipnitz
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal de Rio Grande do Sul, Rua Ramiro Barcelos N° 2600 - Attached, Porto Alegre, RS, CEP: 90035-003, Brazil.
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Dienel GA, Cruz NF. Biochemical, Metabolic, and Behavioral Characteristics of Immature Chronic Hyperphenylalanemic Rats. Neurochem Res 2015. [PMID: 26224289 DOI: 10.1007/s11064-015-1678-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Phenylketonuria and hyperphenylalanemia are inborn errors in metabolism of phenylalanine arising from defects in steps to convert phenylalanine to tyrosine. Phe accumulation causes severe mental retardation that can be prevented by timely identification of affected individuals and their placement on a Phe-restricted diet. In spite of many studies in patients and animal models, the basis for acquisition of mental retardation during the critical period of brain development is not adequately understood. All animal models for human disease have advantages and limitations, and characteristics common to different models are most likely to correspond to the disorder. This study established similar levels of Phe exposure in developing rats between 3 and 16 days of age using three models to produce chronic hyperphenylalanemia, and identified changes in brain amino acid levels common to all models that persist for ~16 h of each day. In a representative model, local rates of glucose utilization (CMRglc) were determined at 25-27 days of age, and only selective changes that appeared to depend on Phe exposure were observed. CMRglc was reduced in frontal cortex and thalamus and increased in hippocampus and globus pallidus. Behavioral testing to evaluate neuromuscular competence revealed poor performance in chronically-hyperphenylalanemic rats that persisted for at least 3 weeks after cessation of Phe injections and did not occur with mild or acute hyperphenylalanemia. Thus, the abnormal amino acid environment, including hyperglycinemia, in developing rat brain is associated with selective regional changes in glucose utilization and behavioral abnormalities that are not readily reversed after they are acquired.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, 4301 W. Markham St., Mail Slot 500, Little Rock, AR, 72205, USA.
| | - Nancy F Cruz
- Department of Neurology, University of Arkansas for Medical Sciences, 4301 W. Markham St., Mail Slot 500, Little Rock, AR, 72205, USA
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11
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Evidence that glycine induces lipid peroxidation and decreases glutathione concentrations in rat cerebellum. Mol Cell Biochem 2014; 395:125-34. [PMID: 24939360 DOI: 10.1007/s11010-014-2118-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 06/02/2014] [Indexed: 02/07/2023]
Abstract
Patients with non-ketotic hyperglycinemia (NKH) present severe neurological symptoms and brain abnormalities involving cerebellum. Although the pathomechanisms underlying the cerebellum damage have not been studied, high tissue levels of glycine (GLY), the biochemical hallmark of this disorder have been suggested to contribute to the neuropathology of this disease. We investigated the in vitro effects of GLY on important parameters of oxidative stress and energy metabolism in cerebellum of 30-day-old rats. Our results show that GLY increased 2',7'-dichlorofluorescin oxidation, suggesting that reactive species production are augmented by GLY in the cerebellum. However, hydrogen peroxide generation was not altered by GLY. GLY also increased thiobarbituric acid-reactive substances (TBA-RS) levels and reduced the glutathione (GSH) content, indicating that this amino acid provokes lipid oxidative damage and compromises the non-enzymatic antioxidant defenses, respectively, in cerebellum. The antioxidants melatonin and trolox (the hydrosoluble analog of vitamin E) prevented the GLY-induced increase of TBA-RS and decrease of GSH in cerebellum, indicating the involvement of hydroxyl and peroxyl radicals in these effects. The NMDA receptor antagonist MK-801 also attenuated GLY-induced decrease of GSH, suggesting that this effect is mediated through NMDA receptor. In contrast, GLY did not alter the protein carbonyl formation and total and protein-bound sulfhydryl group content, as well as catalase and superoxide dismutase activities. Furthermore, GLY did not alter the activities of the respiratory chain complexes and creatine kinase. Our present data indicate that oxidative stress elicited by GLY in vitro may be a potential pathomechanism involved in the cerebellar dysfunction observed in NKH.
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