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Zemniaçak ÂB, Ribeiro RT, Pinheiro CV, de Azevedo Cunha S, Tavares TQ, Castro ET, Leipnitz G, Wajner M, Amaral AU. In Vivo Intracerebral Administration of α-Ketoisocaproic Acid to Neonate Rats Disrupts Brain Redox Homeostasis and Promotes Neuronal Death, Glial Reactivity, and Myelination Injury. Mol Neurobiol 2024; 61:2496-2513. [PMID: 37910283 DOI: 10.1007/s12035-023-03718-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 10/17/2023] [Indexed: 11/03/2023]
Abstract
Maple syrup urine disease (MSUD) is caused by severe deficiency of branched-chain α-keto acid dehydrogenase complex activity, resulting in tissue accumulation of branched-chain α-keto acids and amino acids, particularly α-ketoisocaproic acid (KIC) and leucine. Affected patients regularly manifest with acute episodes of encephalopathy including seizures, coma, and potentially fatal brain edema during the newborn period. The present work investigated the ex vivo effects of a single intracerebroventricular injection of KIC to neonate rats on redox homeostasis and neurochemical markers of neuronal viability (neuronal nuclear protein (NeuN)), astrogliosis (glial fibrillary acidic protein (GFAP)), and myelination (myelin basic protein (MBP) and 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase)) in the cerebral cortex and striatum. KIC significantly disturbed redox homeostasis in these brain structures 6 h after injection, as observed by increased 2',7'-dichlorofluorescein oxidation (reactive oxygen species generation), malondialdehyde levels (lipid oxidative damage), and carbonyl formation (protein oxidative damage), besides impairing the antioxidant defenses (diminished levels of reduced glutathione and altered glutathione peroxidase, glutathione reductase, and superoxide dismutase activities) in both cerebral structures. Noteworthy, the antioxidants N-acetylcysteine and melatonin attenuated or normalized most of the KIC-induced effects on redox homeostasis. Furthermore, a reduction of NeuN, MBP, and CNPase, and an increase of GFAP levels were observed at postnatal day 15, suggesting neuronal loss, myelination injury, and astrocyte reactivity, respectively. Our data indicate that disruption of redox homeostasis, associated with neural damage caused by acute intracerebral accumulation of KIC in the neonatal period may contribute to the neuropathology characteristic of MSUD patients.
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Affiliation(s)
- Ângela Beatris Zemniaçak
- 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
| | - 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
| | - Camila Vieira Pinheiro
- 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
| | - Sâmela de Azevedo Cunha
- 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
| | - Tailine Quevedo Tavares
- 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
| | - Ediandra Tissot Castro
- 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
| | - Guilhian Leipnitz
- 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
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Moacir Wajner
- 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
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Alexandre Umpierrez Amaral
- 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.
- Programa de Pós-Graduação em Atenção Integral à Saúde, Universidade Regional Integrada do Alto Uruguai e das Missões, Avenida Sete de Setembro, 1621, Erechim, RS, 99709-910, Brazil.
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Bortoluzzi VT, Ribeiro RT, Zemniaçak ÂB, Cunha SDA, Sass JO, Castilho RF, Amaral AU, Wajner M. Disturbance of mitochondrial functions caused by N-acetylglutamate and N-acetylmethionine in brain of adolescent rats: Potential relevance in aminoacylase 1 deficiency. Neurochem Int 2023; 171:105631. [PMID: 37852579 DOI: 10.1016/j.neuint.2023.105631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/24/2023] [Accepted: 10/15/2023] [Indexed: 10/20/2023]
Abstract
Aminoacylase 1 (ACY1) deficiency is a rare genetic disorder that affects the breakdown of short-chain aliphatic N-acetylated amino acids, leading to the accumulation of these amino acid derivatives in the urine of patients. Some of the affected individuals have presented with heterogeneous neurological symptoms such as psychomotor delay, seizures, and intellectual disability. Considering that the pathological mechanisms of brain damage in this disorder remain mostly unknown, here we investigated whether major metabolites accumulating in ACY1 deficiency, namely N-acetylglutamate (NAG) and N-acetylmethionine (NAM), could be toxic to the brain by examining their in vitro effects on important mitochondrial properties. We assessed the effects of NAG and NAM on membrane potential, swelling, reducing equivalents, and Ca2+ retention capacity in purified mitochondrial preparations obtained from the brain of adolescent rats. NAG and NAM decreased mitochondrial membrane potential, reducing equivalents, and calcium retention capacity, and induced swelling in Ca2+-loaded brain mitochondria supported by glutamate plus malate. Notably, these changes were completely prevented by the classical inhibitors of mitochondrial permeability transition (MPT) pore cyclosporin A plus ADP and by ruthenium red, implying the participation of MPT and Ca2+ in these effects. Our findings suggest that NAG- and NAM-induced disruption of mitochondrial functions involving MPT may represent relevant mechanisms of neuropathology in ACY1 deficiency.
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Affiliation(s)
- Vanessa Trindade Bortoluzzi
- PPG Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Rafael Teixeira Ribeiro
- PPG Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Ângela Beatris Zemniaçak
- PPG Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Sâmela de Azevedo Cunha
- PPG Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
| | - Jörn Oliver Sass
- Research Group Inborn Errors of Metabolism, Department of Natural Sciences & Institute for Functional Gene Analytics, Bonn-Rhein-Sieg University of Applied Sciences, Rheinbach, Germany.
| | - Roger Frigério Castilho
- Departamento de Patologia, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil.
| | - Alexandre Umpierrez Amaral
- PPG Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; PPG Atenção Integral à Saúde, Universidade Regional Integrada do Alto Uruguai e das Missões, Erechim, Brazil.
| | - Moacir Wajner
- PPG Ciências Biológicas: Bioquímica, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.
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