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Adomako-Bonsu AG, Jacobsen J, Maser E. Metabolic activation of 2,4,6-trinitrotoluene; a case for ROS-induced cell damage. Redox Biol 2024; 72:103082. [PMID: 38527399 PMCID: PMC10979124 DOI: 10.1016/j.redox.2024.103082] [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: 12/05/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 03/27/2024] Open
Abstract
The explosive compound 2,4,6-trinitrotoluene (TNT) is well known as a major component of munitions. In addition to its potential carcinogenicity and mutagenicity in humans, recent reports have highlighted TNT toxicities in diverse organisms due to its occurrence in the environment. These toxic effects have been linked to the intracellular metabolism of TNT, which is generally characterised by redox cycling and the generation of noxious reactive molecules. The reactive intermediates formed, such as nitroso and hydroxylamine compounds, also interact with oxygen molecules and cellular components to cause macromolecular damage and oxidative stress. The current review aims to highlight the crucial role of TNT metabolism in mediating TNT toxicity, via increased generation of reactive oxygen species. Cellular proliferation of reactive species results in depletion of cellular antioxidant enzymes, DNA and protein adduct formation, and oxidative stress. While TNT toxicity is well known, its ability to induce oxidative stress, resulting from its reductive activation, suggests that some of its toxic effects may be caused by its reactive metabolites. Hence, further research on TNT metabolism is imperative to elucidate TNT-induced toxicities.
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Affiliation(s)
- Amma Gyapomah Adomako-Bonsu
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein Campus Kiel, Brunswiker Str. 10, 24105, Kiel, Germany
| | - Jana Jacobsen
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein Campus Kiel, Brunswiker Str. 10, 24105, Kiel, Germany
| | - Edmund Maser
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein Campus Kiel, Brunswiker Str. 10, 24105, Kiel, Germany.
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2
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Roginski AC, Zemniaçak ÂB, Marschner RA, Wajner SM, Ribeiro RT, Wajner M, Amaral AU. Disruption of mitochondrial functions involving mitochondrial permeability transition pore opening caused by maleic acid in rat kidney. J Bioenerg Biomembr 2022; 54:203-213. [PMID: 35902433 DOI: 10.1007/s10863-022-09945-4] [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: 02/27/2022] [Accepted: 07/23/2022] [Indexed: 11/26/2022]
Abstract
Propionic acid (PA) predominantly accumulates in tissues and biological fluids of patients affected by propionic acidemia that may manifest chronic renal failure along development. High urinary excretion of maleic acid (MA) has also been described. Considering that the underlying mechanisms of renal dysfunction in this disorder are poorly known, the present work investigated the effects of PA and MA (1-5 mM) on mitochondrial functions and cellular viability in rat kidney and cultured human embryonic kidney (HEK-293) cells. Mitochondrial membrane potential (∆ψm), NAD(P)H content, swelling and ATP production were measured in rat kidney mitochondrial preparations supported by glutamate or glutamate plus malate, in the presence or absence of Ca2+. MTT reduction and propidium iodide (PI) incorporation were also determined in intact renal cells pre-incubated with MA or PA for 24 h. MA decreased Δψm and NAD(P)H content and induced swelling in Ca2+-loaded mitochondria either respiring with glutamate or glutamate plus malate. Noteworthy, these alterations were fully prevented by cyclosporin A plus ADP, suggesting the involvement of mitochondrial permeability transition (mPT). MA also markedly inhibited ATP synthesis in kidney mitochondria using the same substrates, implying a strong bioenergetics impairment. In contrast, PA only caused milder changes in these parameters. Finally, MA decreased MTT reduction and increased PI incorporation in intact HEK-293 cells, indicating a possible association between mitochondrial dysfunction and cell death in an intact cell system. It is therefore presumed that the MA-induced disruption of mitochondrial functions involving mPT pore opening may be involved in the chronic renal failure occurring in propionic acidemia.
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Affiliation(s)
- Ana Cristina Roginski
- 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
| | - 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 Aguiar Marschner
- Departamento de Medicina Interna, Faculdade de Medicina, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, RS, Brazil
| | - Simone Magagnin Wajner
- Departamento de Medicina Interna, Faculdade de Medicina, 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
| | - 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.
- Departamento de Ciências Biológicas, Universidade Regional Integrada Do Alto Uruguai E das Missões, Avenida Sete de Setembro, 1621, Erechim, RS, CEP 99709-910, Brazil.
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3
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Abstract
Significance: Aging is a natural process that affects most living organisms, resulting in increased mortality. As the world population ages, the prevalence of age-associated diseases, and their associated health care costs, has increased sharply. A better understanding of the molecular mechanisms that lead to cellular dysfunction may provide important targets for interventions to prevent or treat these diseases. Recent Advances: Although the mitochondrial theory of aging had been proposed more than 40 years ago, recent new data have given stronger support for a central role for mitochondrial dysfunction in several pathways that are deregulated during normal aging and age-associated disease. Critical Issues: Several of the experimental evidence linking mitochondrial alterations to age-associated loss of function are correlative and mechanistic insights are still elusive. Here, we review how mitochondrial dysfunction may be involved in many of the known hallmarks of aging, and how these pathways interact in an intricate net of molecular relationships. Future Directions: As it has become clear that mitochondrial dysfunction plays causative roles in normal aging and age-associated diseases, it is necessary to better define the molecular interactions and the temporal and causal relationship between these changes and the relevant phenotypes seen during the aging process. Antioxid. Redox Signal. 36, 824-843.
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Affiliation(s)
- Caio M P F Batalha
- Lab. Genética Mitocondrial, Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Anibal Eugênio Vercesi
- Departamento de Patologia Clínica, Faculdade de Medicina, Universidade de Campinas, Campinas, Brazil
| | - Nadja C Souza-Pinto
- Lab. Genética Mitocondrial, Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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4
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Francisco A, Figueira TR, Castilho RF. Mitochondrial NAD(P) + Transhydrogenase: From Molecular Features to Physiology and Disease. Antioxid Redox Signal 2022; 36:864-884. [PMID: 34155914 DOI: 10.1089/ars.2021.0111] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Significance: Proton-translocating NAD(P)+ transhydrogenase, also known as nicotinamide nucleotide transhydrogenase (NNT), catalyzes a reversible reaction coupling the protonmotive force across the inner mitochondrial membrane and hydride (H-, a proton plus two electrons) transfer between the mitochondrial pools of NAD(H) and NADP(H). The forward NNT reaction is a source of NADPH in the mitochondrial matrix, fueling antioxidant and biosynthetic pathways with reductive potential. Despite the greater emphasis given to the net forward reaction, the reverse NNT reaction that oxidizes NADPH also occurs in physiological and pathological conditions. Recent Advances: NNT (dys)function has been linked to various metabolic pathways and disease phenotypes. Most of these findings have been based on spontaneous loss-of-function Nnt mutations found in the C57BL/6J mouse strain (NntC57BL/6J mutation) and disease-causing Nnt mutations in humans. The present review focuses on recent advances based on the mouse NntC57BL/6J mutation. Critical Issues: Most studies associating NNT function with disease phenotypes have been based on comparisons between different strains of inbred mice (with or without the NntC57BL/6J mutation), which creates uncertainties over the actual contribution of NNT in the context of other potential genetic modifiers. Future Directions: Future research might contribute to understanding the role of NNT in pathological conditions and elucidate how NNT regulates physiological signaling through its forward and reverse reactions. The importance of NNT in redox balance and tumor cell proliferation makes it a potential target of new therapeutic strategies for oxidative-stress-mediated diseases and cancer. Antioxid. Redox Signal. 36, 864-884.
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Affiliation(s)
- Annelise Francisco
- Department of Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
| | - Tiago Rezende Figueira
- School of Physical Education and Sport of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, Brazil
| | - Roger Frigério Castilho
- Department of Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, Brazil
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5
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Sartori MR, Navarro CDC, Castilho RF, Vercesi AE. Enhanced resistance to Ca2+-induced mitochondrial permeability transition in the long-lived red-footed tortoise Chelonoidis carbonaria. J Exp Biol 2022; 225:jeb243532. [PMID: 34904632 DOI: 10.1242/jeb.243532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 12/08/2021] [Indexed: 11/20/2022]
Abstract
The interaction between supraphysiological cytosolic Ca2+ levels and mitochondrial redox imbalance mediates the mitochondrial permeability transition (MPT). The MPT is involved in cell death, diseases and aging. This study compared the liver mitochondrial Ca2+ retention capacity and oxygen consumption in the long-lived red-footed tortoise (Chelonoidis carbonaria) with those in the rat as a reference standard. Mitochondrial Ca2+ retention capacity, a quantitative measure of MPT sensitivity, was remarkably higher in tortoises than in rats. This difference was minimized in the presence of the MPT inhibitors ADP and cyclosporine A. However, the Ca2+ retention capacities of tortoise and rat liver mitochondria were similar when both MPT inhibitors were present simultaneously. NADH-linked phosphorylating respiration rates of tortoise liver mitochondria represented only 30% of the maximal electron transport system capacity, indicating a limitation imposed by the phosphorylation system. These results suggested underlying differences in putative MPT structural components [e.g. ATP synthase, adenine nucleotide translocase (ANT) and cyclophilin D] between tortoises and rats. Indeed, in tortoise mitochondria, titrations of inhibitors of the oxidative phosphorylation components revealed a higher limitation of ANT. Furthermore, cyclophilin D activity was approximately 70% lower in tortoises than in rats. Investigation of critical properties of mitochondrial redox control that affect MPT demonstrated that tortoise and rat liver mitochondria exhibited similar rates of H2O2 release and glutathione redox status. Overall, our findings suggest that constraints imposed by ANT and cyclophilin D, putative components or regulators of the MPT pore, are associated with the enhanced resistance to Ca2+-induced MPT in tortoises.
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Affiliation(s)
- Marina R Sartori
- Department of Pathology, Faculty of Medical Sciences, University of Campinas, Campinas, SP 13083-887, Brazil
| | - Claudia D C Navarro
- Department of Pathology, Faculty of Medical Sciences, University of Campinas, Campinas, SP 13083-887, Brazil
| | - Roger F Castilho
- Department of Pathology, Faculty of Medical Sciences, University of Campinas, Campinas, SP 13083-887, Brazil
| | - Anibal E Vercesi
- Department of Pathology, Faculty of Medical Sciences, University of Campinas, Campinas, SP 13083-887, Brazil
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6
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Figueira TR, Francisco A, Ronchi JA, Dos Santos GRRM, Santos WD, Treberg JR, Castilho RF. NADPH supply and the contribution of NAD(P) + transhydrogenase (NNT) to H 2O 2 balance in skeletal muscle mitochondria. Arch Biochem Biophys 2021; 707:108934. [PMID: 34043997 DOI: 10.1016/j.abb.2021.108934] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 04/27/2021] [Accepted: 05/19/2021] [Indexed: 10/21/2022]
Abstract
H2O2 is endogenously generated and its removal in the matrix of skeletal muscle mitochondria (SMM) is dependent on NADPH likely provided by NAD(P)+ transhydrogenase (NNT) and isocitrate dehydrogenase (IDH2). Importantly, NNT activity is linked to mitochondrial protonmotive force. Here, we demonstrate the presence of NNT function in detergent-solubilized and intact functional SMM isolated from rats and wild type (Nnt+/+) mice, but not in SMM from congenic mice carrying a mutated NNT gene (Nnt-/-). Further comparisons between SMM from both Nnt mouse genotypes revealed that the NADPH supplied by NNT supports up to 600 pmol/mg/min of H2O2 removal under selected conditions. Surprisingly, SMM from Nnt-/- mice removed exogenous H2O2 at wild-type levels and exhibited a maintained or even decreased net emission of endogenous H2O2 when substrates that support Krebs cycle reactions were present (e.g., pyruvate plus malate or palmitoylcarnitine plus malate). These results may be explained by a compensation for the lack of NNT, since the total activities of concurrent NADP+-reducing enzymes (IDH2, malic enzymes and glutamate dehydrogenase) were ~70% elevated in Nnt-/- mice. Importantly, respiratory rates were similar between SMM from both Nnt genotypes despite differing NNT contributions to H2O2 removal and their implications for an evolving concept in the literature are discussed. We concluded that NNT is capable of meaningfully sustaining NADPH-dependent H2O2 removal in intact SMM. Nonetheless, if the available substrates favor non-NNT sources of NADPH, the H2O2 removal by SMM is maintained in Nnt-/- mice SMM.
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Affiliation(s)
- Tiago R Figueira
- Department of Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Rua Tessália Vieira de Camargo, 126, 13083-887, Campinas, SP, Brazil.
| | - Annelise Francisco
- Department of Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Rua Tessália Vieira de Camargo, 126, 13083-887, Campinas, SP, Brazil
| | - Juliana A Ronchi
- Department of Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Rua Tessália Vieira de Camargo, 126, 13083-887, Campinas, SP, Brazil
| | - Guilherme R R M Dos Santos
- Department of Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Rua Tessália Vieira de Camargo, 126, 13083-887, Campinas, SP, Brazil
| | - William Dos Santos
- Department of Biological Sciences, University of Manitoba, General Office 212B Bio-Sci Bldg., R3T 2N2, Winnipeg, MB, Canada
| | - Jason R Treberg
- Department of Biological Sciences, University of Manitoba, General Office 212B Bio-Sci Bldg., R3T 2N2, Winnipeg, MB, Canada; Centre on Aging, University of Manitoba, Winnipeg, MB, Canada
| | - Roger F Castilho
- Department of Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Rua Tessália Vieira de Camargo, 126, 13083-887, Campinas, SP, Brazil
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7
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Bicego R, Francisco A, Ruas JS, Siqueira-Santos ES, Castilho RF. Undesirable effects of chemical inhibitors of NAD(P) + transhydrogenase on mitochondrial respiratory function. Arch Biochem Biophys 2020; 692:108535. [PMID: 32781052 DOI: 10.1016/j.abb.2020.108535] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 07/31/2020] [Indexed: 10/23/2022]
Abstract
NAD(P)+ transhydrogenase (NNT) is located in the inner mitochondrial membrane and catalyzes a reversible hydride transfer between NAD(H) and NADP(H) that is coupled to proton translocation between the intermembrane space and mitochondrial matrix. NNT activity has an essential role in maintaining the NADPH supply for antioxidant defense and biosynthetic pathways. In the present report, we evaluated the effects of chemical compounds used as inhibitors of NNT over the last five decades, namely, 4-chloro-7-nitrobenzofurazan (NBD-Cl), N,N'-dicyclohexylcarbodiimide (DCC), palmitoyl-CoA, palmitoyl-l-carnitine, and rhein, on NNT activity and mitochondrial respiratory function. Concentrations of these compounds that partially inhibited the forward and reverse NNT reactions in detergent-solubilized mouse liver mitochondria significantly impaired mitochondrial respiratory function, as estimated by ADP-stimulated and nonphosphorylating respiration. Among the tested compounds, NBD-Cl showed the best relationship between NNT inhibition and low impact on respiratory function. Despite this, NBD-Cl concentrations that partially inhibited NNT activity impaired mitochondrial respiratory function and significantly decreased the viability of cultured Nnt-/- mouse astrocytes. We conclude that even though the tested compounds indeed presented inhibitory effects on NNT activity, at effective concentrations, they cause important undesirable effects on mitochondrial respiratory function and cell viability.
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Affiliation(s)
- Rafaela Bicego
- Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Annelise Francisco
- Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil.
| | - Juliana S Ruas
- Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Edilene S Siqueira-Santos
- Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Roger F Castilho
- Department of Clinical Pathology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil.
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8
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Roginski AC, Wajner A, Cecatto C, Wajner SM, Castilho RF, Wajner M, Amaral AU. Disturbance of bioenergetics and calcium homeostasis provoked by metabolites accumulating in propionic acidemia in heart mitochondria of developing rats. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165682. [PMID: 31931102 DOI: 10.1016/j.bbadis.2020.165682] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 12/14/2022]
Abstract
Propionic acidemia is caused by lack of propionyl-CoA carboxylase activity. It is biochemically characterized by accumulation of propionic (PA) and 3-hydroxypropionic (3OHPA) acids and clinically by severe encephalopathy and cardiomyopathy. High urinary excretion of maleic acid (MA) and 2-methylcitric acid (2MCA) is also found in the affected patients. Considering that the underlying mechanisms of cardiac disease in propionic acidemia are practically unknown, we investigated the effects of PA, 3OHPA, MA and 2MCA (0.05-5 mM) on important mitochondrial functions in isolated rat heart mitochondria, as well as in crude heart homogenates and cultured cardiomyocytes. MA markedly inhibited state 3 (ADP-stimulated), state 4 (non-phosphorylating) and uncoupled (CCCP-stimulated) respiration in mitochondria supported by pyruvate plus malate or α-ketoglutarate associated with reduced ATP production, whereas PA and 3OHPA provoked less intense inhibitory effects and 2MCA no alterations at all. MA-induced impaired respiration was attenuated by coenzyme A supplementation. In addition, MA significantly inhibited α-ketoglutarate dehydrogenase activity. Similar data were obtained in heart crude homogenates and permeabilized cardiomyocytes. MA, and PA to a lesser degree, also decreased mitochondrial membrane potential (ΔΨm), NAD(P)H content and Ca2+ retention capacity, and caused swelling in Ca2+-loaded mitochondria. Noteworthy, ΔΨm collapse and mitochondrial swelling were fully prevented or attenuated by cyclosporin A and ADP, indicating the involvement of mitochondrial permeability transition. It is therefore proposed that disturbance of mitochondrial energy and calcium homeostasis caused by MA, as well as by PA and 3OHPA to a lesser extent, may be involved in the cardiomyopathy commonly affecting propionic acidemic patients.
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Affiliation(s)
- Ana Cristina Roginski
- 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
| | - Alessandro 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
| | - 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
| | - Simone Magagnin Wajner
- Departamento de Medicina Interna, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Roger Frigério Castilho
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, 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; Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Departamento de Ciências Biológicas, Universidade Regional Integrada do Alto Uruguai e das Missões, Erechim, RS, Brazil.
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9
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Oliveira HCF, Vercesi AE. Mitochondrial bioenergetics and redox dysfunctions in hypercholesterolemia and atherosclerosis. Mol Aspects Med 2019; 71:100840. [PMID: 31882067 DOI: 10.1016/j.mam.2019.100840] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/19/2019] [Accepted: 12/20/2019] [Indexed: 12/12/2022]
Abstract
In the first part of this review, we summarize basic mitochondrial bioenergetics concepts showing that mitochondria are critical regulators of cell life and death. Until a few decades ago, mitochondria were considered to play essential roles only in respiration, ATP formation, non-shivering thermogenesis and a variety of metabolic pathways. However, the concept presented by Peter Mitchell regarding coupling between electron flow and ATP synthesis through the intermediary of a H+ electrochemical potential leads to the recognition that the proton-motive force also regulates a series of relevant cell signalling processes, such as superoxide generation, redox balance and Ca2+ handling. Alterations in these processes lead to cell death and disease states. In the second part of this review, we discuss the role of mitochondrial dysfunctions in the specific context of hypercholesterolemia-induced atherosclerosis. We provide a literature analysis that indicates a decisive role of mitochondrial redox dysfunction in the development of atherosclerosis and discuss the underlying molecular mechanisms. Finally, we highlight the potential mitochondrial-targeted therapeutic strategies that are relevant for atherosclerosis.
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Affiliation(s)
- Helena C F Oliveira
- Department of Structural and Functional Biology, Biology Institute, State University of Campinas, Campinas, SP, Brazil.
| | - Anibal E Vercesi
- Department of Clinical Pathology, Faculty of Medical Sciences, State University of Campinas, Campinas, SP, Brazil.
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10
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Vercesi AE, Castilho RF, Kowaltowski AJ, de Oliveira HCF, de Souza-Pinto NC, Figueira TR, Busanello ENB. Mitochondrial calcium transport and the redox nature of the calcium-induced membrane permeability transition. Free Radic Biol Med 2018; 129:1-24. [PMID: 30172747 DOI: 10.1016/j.freeradbiomed.2018.08.034] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/16/2018] [Accepted: 08/28/2018] [Indexed: 12/16/2022]
Abstract
Mitochondria possess a Ca2+ transport system composed of separate Ca2+ influx and efflux pathways. Intramitochondrial Ca2+ concentrations regulate oxidative phosphorylation, required for cell function and survival, and mitochondrial redox balance, that participates in a myriad of signaling and damaging pathways. The interaction between Ca2+ accumulation and redox imbalance regulates opening and closing of a highly regulated inner membrane pore, the membrane permeability transition pore (PTP). In this review, we discuss the regulation of the PTP by mitochondrial oxidants, reactive nitrogen species, and the interactions between these species and other PTP inducers. In addition, we discuss the involvement of mitochondrial redox imbalance and PTP in metabolic conditions such as atherogenesis, diabetes, obesity and in mtDNA stability.
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Affiliation(s)
- Anibal E Vercesi
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil.
| | - Roger F Castilho
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Alicia J Kowaltowski
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Helena C F de Oliveira
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas, SP, Brazil
| | - Nadja C de Souza-Pinto
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Tiago R Figueira
- Escola de Educação Física e Esporte de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Estela N B Busanello
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brazil
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11
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Navarro CDC, Figueira TR, Francisco A, Dal'Bó GA, Ronchi JA, Rovani JC, Escanhoela CAF, Oliveira HCF, Castilho RF, Vercesi AE. Redox imbalance due to the loss of mitochondrial NAD(P)-transhydrogenase markedly aggravates high fat diet-induced fatty liver disease in mice. Free Radic Biol Med 2017; 113:190-202. [PMID: 28964917 DOI: 10.1016/j.freeradbiomed.2017.09.026] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/30/2017] [Accepted: 09/26/2017] [Indexed: 02/07/2023]
Abstract
The mechanisms by which a high fat diet (HFD) promotes non-alcoholic fatty liver disease (NAFLD) appear to involve liver mitochondrial dysfunctions and redox imbalance. We hypothesized that a HFD would increase mitochondrial reliance on NAD(P)-transhydrogenase (NNT) as the source of NADPH for antioxidant systems that counteract NAFLD development. Therefore, we studied HFD-induced liver mitochondrial dysfunctions and NAFLD in C57Unib.B6 congenic mice with (Nnt+/+) or without (Nnt-/-) NNT activity; the spontaneously mutated allele (Nnt-/-) was inherited from the C57BL/6J mouse substrain. After 20 weeks on a HFD, Nnt-/- mice exhibited a higher prevalence of steatohepatitis and content of liver triglycerides compared to Nnt+/+ mice on an identical diet. Under a HFD, the aggravated NAFLD phenotype in the Nnt-/- mice was accompanied by an increased H2O2 release rate from mitochondria, decreased aconitase activity (a redox-sensitive mitochondrial enzyme) and higher susceptibility to Ca2+-induced mitochondrial permeability transition. In addition, HFD led to the phosphorylation (inhibition) of pyruvate dehydrogenase (PDH) and markedly reduced the ability of liver mitochondria to remove peroxide in Nnt-/- mice. Bypass or pharmacological reactivation of PDH by dichloroacetate restored the peroxide removal capability of mitochondria from Nnt-/- mice on a HFD. Noteworthy, compared to mice that were chow-fed, the HFD did not impair peroxide removal nor elicit redox imbalance in mitochondria from Nnt+/+ mice. Therefore, HFD interacted with Nnt mutation to generate PDH inhibition and further suppression of peroxide removal. We conclude that NNT plays a critical role in counteracting mitochondrial redox imbalance, PDH inhibition and advancement of NAFLD in mice fed a HFD. The present study provide seminal experimental evidence that redox imbalance in liver mitochondria potentiates the progression from simple steatosis to steatohepatitis following a HFD.
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Affiliation(s)
- Claudia D C Navarro
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887 Campinas, SP, Brazil
| | - Tiago R Figueira
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887 Campinas, SP, Brazil
| | - Annelise Francisco
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887 Campinas, SP, Brazil
| | - Genoefa A Dal'Bó
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887 Campinas, SP, Brazil
| | - Juliana A Ronchi
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887 Campinas, SP, Brazil
| | - Juliana C Rovani
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), 13083-865 Campinas, SP, Brazil
| | - Cecilia A F Escanhoela
- Departamento de Anatomia Patológica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887 Campinas, SP, Brazil
| | - Helena C F Oliveira
- Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), 13083-865 Campinas, SP, Brazil
| | - Roger F Castilho
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887 Campinas, SP, Brazil.
| | - Anibal E Vercesi
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887 Campinas, SP, Brazil.
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Marín-Prida J, Pardo Andreu GL, Rossignoli CP, Durruthy MG, Rodríguez EO, Reyes YV, Acosta RF, Uyemura SA, Alberici LC. The cytotoxic effects of VE-3N, a novel 1,4-dihydropyridine derivative, involve the mitochondrial bioenergetic disruption via uncoupling mechanisms. Toxicol In Vitro 2017; 42:21-30. [PMID: 28363597 DOI: 10.1016/j.tiv.2017.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 03/03/2017] [Accepted: 03/27/2017] [Indexed: 01/21/2023]
Abstract
Several 1,4-dihydropyridine derivatives overcome the multidrug resistance in tumors, but their intrinsic cytotoxic mechanisms remain unclear. Here we addressed if mitochondria are involved in the cytotoxicity of the novel 1,4-dihydropyridine derivative VE-3N [ethyl 6-chloro-5-formyl-2-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylate] towards cancer cells by employing hepatic carcinoma (HepG2) cells and isolated rat liver mitochondria. In HepG2 cells, VE-3N induced mitochondrial membrane potential dissipation, ATP depletion, annexin V/propidium iodide double labeling, and Hoechst staining; events indicating apoptosis induction. In isolated rat liver mitochondria, VE-3N promoted mitochondrial uncoupling by exerting protonophoric actions and by increasing membrane fluidity. Mitochondrial uncoupling was evidenced by an increase in resting respiration, dissipation of mitochondrial membrane potential, inhibition of Ca2+ uptake, stimulation of Ca2+ release, decrease in ATP synthesis, and swelling of valinomycin-treated organelles in hyposmotic potassium acetate media. Furthermore, uncoupling concentrations of VE-3N in the presence of Ca2+ plus ruthenium red induced the mitochondrial permeability transition process. These results indicate that mitochondrial uncoupling is potentially involved in the VE-3N cytotoxic actions towards HepG2 cells. Considering that hepatocellular carcinoma is the most common form of liver cancer, our findings may open a new avenue for the development of VE-3N-based cancer therapies, and help to unravel the cytotoxic mechanisms of 1,4-dihydropyridines towards cancer cells.
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Affiliation(s)
- Javier Marín-Prida
- Center for Research and Biological Evaluations, Institute of Pharmacy and Food, University of Havana, 222 St. # 2317, La Coronela, La Lisa, Havana, Cuba
| | - Gilberto L Pardo Andreu
- Center for Research and Biological Evaluations, Institute of Pharmacy and Food, University of Havana, 222 St. # 2317, La Coronela, La Lisa, Havana, Cuba.
| | - Camila Pederiva Rossignoli
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. Café s/n, 14040-903, Ribeirão Preto, São Paulo, Brazil
| | - Michael González Durruthy
- Center for Research and Biological Evaluations, Institute of Pharmacy and Food, University of Havana, 222 St. # 2317, La Coronela, La Lisa, Havana, Cuba
| | - Estael Ochoa Rodríguez
- Laboratory of Organic Synthesis, Faculty of Chemistry, University of Havana, Zapata st./G and Carlitos Aguirre, Vedado Plaza de la Revolución, PO 10400, Havana, Cuba
| | - Yamila Verdecia Reyes
- Laboratory of Organic Synthesis, Faculty of Chemistry, University of Havana, Zapata st./G and Carlitos Aguirre, Vedado Plaza de la Revolución, PO 10400, Havana, Cuba
| | - Roberto Fernández Acosta
- Department of Pharmacy, Institute of Pharmacy and Food, University of Havana, 222 St. # 2317, La Coronela, La Lisa, Havana, Cuba
| | - Sergio A Uyemura
- Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. Café s/n, 14040-903 Ribeirão Preto, São Paulo, Brazil
| | - Luciane C Alberici
- Department of Physics and Chemistry, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. Café s/n, 14040-903, Ribeirão Preto, São Paulo, Brazil
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13
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Ronchi JA, Francisco A, Passos LAC, Figueira TR, Castilho RF. The Contribution of Nicotinamide Nucleotide Transhydrogenase to Peroxide Detoxification Is Dependent on the Respiratory State and Counterbalanced by Other Sources of NADPH in Liver Mitochondria. J Biol Chem 2016; 291:20173-87. [PMID: 27474736 DOI: 10.1074/jbc.m116.730473] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Indexed: 11/06/2022] Open
Abstract
The forward reaction of nicotinamide nucleotide transhydrogenase (NNT) reduces NADP(+) at the expense of NADH oxidation and H(+) movement down the electrochemical potential across the inner mitochondrial membrane, establishing an NADPH/NADP(+) ratio severalfold higher than the NADH/NAD(+) ratio in the matrix. In turn, NADPH drives processes, such as peroxide detoxification and reductive biosynthesis. In this study, we generated a congenic mouse model carrying a mutated Nnt(C57BL/6J) allele from the C57BL/6J substrain. Suspensions of isolated mitochondria from Nnt(+/+), Nnt(+/-), and Nnt(-/-) mouse liver were biochemically evaluated and challenged with exogenous peroxide under different respiratory states. The respiratory substrates were also varied, and the participation of concurrent NADPH sources (i.e. isocitrate dehydrogenase-2, malic enzymes, and glutamate dehydrogenase) was assessed. The principal findings include the following: Nnt(+/-) and Nnt(-/-) exhibit ∼50% and absent NNT activity, respectively, but the activities of concurrent NADPH sources are unchanged. The lack of NNT activity in Nnt(-/-) mice impairs peroxide metabolism in intact mitochondria. The contribution of NNT to peroxide metabolism is decreased during ADP phosphorylation compared with the non-phosphorylating state; however, it is accompanied by increased contributions of concurrent NADPH sources, especially glutamate dehydrogenase. NNT makes a major contribution to peroxide metabolism during the blockage of mitochondrial electron transport. Interestingly, peroxide metabolism in the Nnt(+/-) mitochondria matched that in the Nnt(+/+) mitochondria. Overall, this study demonstrates that the respiratory state and/or substrates that sustain energy metabolism markedly influence the relative contribution of NNT (i.e. varies between nearly 0 and 100%) to NADPH-dependent mitochondrial peroxide metabolism.
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Affiliation(s)
| | - Annelise Francisco
- From the Department of Clinical Pathology, Faculty of Medical Sciences, and
| | - Luiz Augusto Correa Passos
- Multidisciplinary Center for Biological Investigation on Laboratory Animals Science, University of Campinas, Campinas SP 13083-877, Brazil
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Increased Susceptibility of Gracilinanus microtarsus Liver Mitochondria to Ca²⁺-Induced Permeability Transition Is Associated with a More Oxidized State of NAD(P). OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2015:940627. [PMID: 26583063 PMCID: PMC4637094 DOI: 10.1155/2015/940627] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/22/2015] [Accepted: 05/27/2015] [Indexed: 01/21/2023]
Abstract
In addition to be the cell's powerhouse, mitochondria also contain a cell death machinery that includes highly regulated processes such as the membrane permeability transition pore (PTP) and reactive oxygen species (ROS) production. In this context, the results presented here provide evidence that liver mitochondria isolated from Gracilinanus microtarsus, a small and short life span (one year) marsupial, when compared to mice, are much more susceptible to PTP opening in association with a poor NADPH dependent antioxidant capacity. Liver mitochondria isolated from the marsupial are well coupled and take up Ca2+ but exhibited a much lower Ca2+ retention capacity than mouse mitochondria. Although the known PTP inhibitors cyclosporin A, ADP, and ATP significantly increased the marsupial mitochondria capacity to retain Ca2+, their effects were much larger in mice than in marsupial mitochondria. Both fluorescence and HPLC analysis of mitochondrial nicotinamide nucleotides showed that both content and state of reduction (mainly of NADPH) were lower in the marsupial mitochondria than in mice mitochondria despite the similarity in the activity of the glutathione peroxidase/reductase system. Overall, these data suggest that PTP opening is an important event in processes of Ca2+ signalling to cell death mediated by mitochondrial redox imbalance in G. microtarsus.
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A lectin from Bothrops leucurus snake venom raises cytosolic calcium levels and promotes B16-F10 melanoma necrotic cell death via mitochondrial permeability transition. Toxicon 2014; 82:97-103. [PMID: 24593964 DOI: 10.1016/j.toxicon.2014.02.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 02/18/2014] [Accepted: 02/20/2014] [Indexed: 11/22/2022]
Abstract
BlL, a galactose-binding C-type lectin purified from Bothrops leucurus snake venom, exhibits anticancer activity. The current study was designed to elucidate the cellular mechanisms by which BlL induces melanoma cell death. The viabilities of B16-F10 melanoma cells and HaCaT keratinocytes treated with BlL were evaluated. Necrotic and apoptotic cell death, cytosolic Ca(2+) levels, mitochondrial Ca(2+) transport and superoxide levels were assessed in B16-F10 melanoma cells exposed to BlL. We found that treatment with BlL caused dose-dependent necrotic cell death in B16-F10 melanoma cells. Conversely, the viability of non-tumorigenic HaCaT cells was not affected by similar doses of BlL. BlL-induced B16-F10 necrosis was preceded by a significant (2-fold) increase in cytosolic calcium concentrations and a significant (3-fold) increase in mitochondrial superoxide generation. It is likely that BlL treatment triggers B16-F10 cell death via mitochondrial permeability transition (MPT) pore opening because the pharmacological MPT inhibitors bongkrekic acid and Debio 025 greatly attenuated BlL-induced cell death. Experiments evaluating mitochondrial Ca(2+) transport in permeabilized B16-F10 cells strongly supported the hypothesis that BlL rapidly stimulates cyclosporine A-sensitive Ca(2+)-induced MPT pore opening. We therefore conclude that BlL causes selective B16-F10 melanoma cell death via dysregulation of cellular Ca(2+) homeostasis and Ca(2+)-induced opening of MPT pore.
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Clusianone, a naturally occurring nemorosone regioisomer, uncouples rat liver mitochondria and induces HepG2 cell death. Chem Biol Interact 2014; 212:20-9. [PMID: 24491676 DOI: 10.1016/j.cbi.2014.01.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 01/15/2014] [Accepted: 01/23/2014] [Indexed: 12/22/2022]
Abstract
Clusianone is a member of the polycyclic polyprenylated acylphloroglucinol family of natural products; its cytotoxic mechanism is unknown. Clusianone is a structural isomer of nemorosone, which is a mitochondrial uncoupler and a well-known cytotoxic anti-cancer agent; thus, we addressed clusianone action at the mitochondria and its potential cytotoxic effects on cancer cells. In the HepG2 hepatocarcinoma cell line, clusianone induced mitochondrial membrane potential dissipation, ATP depletion and phosphatidyl serine externalization; this later event is indicative of apoptosis induction. In isolated mitochondria from rat liver, clusianone promoted protonophoric mitochondrial uncoupling. This was evidenced by the dissipation of mitochondrial membrane potential, an increase in resting respiration, an inhibition of Ca(2+) influx, stimulation of Ca(2+) efflux in Ca(2+)-loaded mitochondria, a decrease in ATP and NAD(P)H levels, generation of ROS, and swelling of valinomycin-treated organelles in hyposmotic potassium acetate media. The cytotoxic and uncoupling actions of clusianone were appreciably less than those of nemorosone, likely due to the presence of an intra-molecular hydrogen bond with the juxtaposed carbonyl group at the C15 position. Therefore, clusianone is capable of pharmacologically increasing the leakage of protons from the mitochondria and with favorable cytotoxicity in relation to nemorosone.
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Ronchi JA, Figueira TR, Ravagnani FG, Oliveira HCF, Vercesi AE, Castilho RF. A spontaneous mutation in the nicotinamide nucleotide transhydrogenase gene of C57BL/6J mice results in mitochondrial redox abnormalities. Free Radic Biol Med 2013; 63:446-56. [PMID: 23747984 DOI: 10.1016/j.freeradbiomed.2013.05.049] [Citation(s) in RCA: 193] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 05/15/2013] [Accepted: 05/31/2013] [Indexed: 02/07/2023]
Abstract
NADPH is the reducing agent for mitochondrial H2O2 detoxification systems. Nicotinamide nucleotide transhydrogenase (NNT), an integral protein located in the inner mitochondrial membrane, contributes to an elevated mitochondrial NADPH/NADP(+) ratio. This enzyme catalyzes the reduction of NADP(+) at the expense of NADH oxidation and H(+) reentry to the mitochondrial matrix. A spontaneous Nnt mutation in C57BL/6J (B6J-Nnt(MUT)) mice arose nearly 3 decades ago but was only discovered in 2005. Here, we characterize the consequences of the Nnt mutation on the mitochondrial redox functions of B6J-Nnt(MUT) mice. Liver mitochondria were isolated both from an Nnt wild-type C57BL/6 substrain (B6JUnib-Nnt(W)) and from B6J-Nnt(MUT) mice. The functional evaluation of respiring mitochondria revealed major redox alterations in B6J-Nnt(MUT) mice, including an absence of transhydrogenation between NAD and NADP, higher rates of H2O2 release, the spontaneous oxidation of NADPH, the poor ability to metabolize organic peroxide, and a higher susceptibility to undergo Ca(2+)-induced mitochondrial permeability transition. In addition, the mitochondria of B6J-Nnt(MUT) mice exhibited increased oxidized/reduced glutathione ratios as compared to B6JUnib-Nnt(W) mice. Nonetheless, the maximal activity of NADP-dependent isocitrate dehydrogenase, which is a coexisting source of mitochondrial NADPH, was similar between both groups. Altogether, our data suggest that NNT functions as a high-capacity source of mitochondrial NADPH and that its functional loss due to the Nnt mutation results in mitochondrial redox abnormalities, most notably a poor ability to sustain NADP and glutathione in their reduced states. In light of these alterations, the potential drawbacks of using B6J-Nnt(MUT) mice in biomedical research should not be overlooked.
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Affiliation(s)
- Juliana A Ronchi
- Department of Clinical Pathology, Faculty of Medical Sciences, State University of Campinas, Campinas, SP 13083-887, Brazil
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18
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Figueira TR, Barros MH, Camargo AA, Castilho RF, Ferreira JCB, Kowaltowski AJ, Sluse FE, Souza-Pinto NC, Vercesi AE. Mitochondria as a source of reactive oxygen and nitrogen species: from molecular mechanisms to human health. Antioxid Redox Signal 2013; 18:2029-74. [PMID: 23244576 DOI: 10.1089/ars.2012.4729] [Citation(s) in RCA: 304] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Mitochondrially generated reactive oxygen species are involved in a myriad of signaling and damaging pathways in different tissues. In addition, mitochondria are an important target of reactive oxygen and nitrogen species. Here, we discuss basic mechanisms of mitochondrial oxidant generation and removal and the main factors affecting mitochondrial redox balance. We also discuss the interaction between mitochondrial reactive oxygen and nitrogen species, and the involvement of these oxidants in mitochondrial diseases, cancer, neurological, and cardiovascular disorders.
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Affiliation(s)
- Tiago R Figueira
- Department of Clinical Pathology, Faculty of Medical Sciences, State University of Campinas, Campinas, Brazil
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19
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Cardiotoxicity of acetogenins from Persea americana occurs through the mitochondrial permeability transition pore and caspase-dependent apoptosis pathways. J Bioenerg Biomembr 2012; 44:461-71. [DOI: 10.1007/s10863-012-9452-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 05/30/2012] [Indexed: 11/25/2022]
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20
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Figueira TR, Castilho RF, Saito A, Oliveira HCF, Vercesi AE. The higher susceptibility of congenital analbuminemic rats to Ca2+-induced mitochondrial permeability transition is associated with the increased expression of cyclophilin D and nitrosothiol depletion. Mol Genet Metab 2011; 104:521-8. [PMID: 21963200 DOI: 10.1016/j.ymgme.2011.08.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 08/30/2011] [Accepted: 08/30/2011] [Indexed: 11/29/2022]
Abstract
Congenital analbuminemia is a rare autosomal recessive disorder characterized by a trace level of albumin in blood plasma and mild clinical symptoms. Analbuminemic patients generally present associated abnormalities, among which dyslipidemia is a hallmark. In this study, we show that mitochondria isolated from different tissues (liver, heart and brain) from 3-month-old analbuminemic rats (NAR) present a higher susceptibility to Ca(2+)-induced mitochondrial permeability transition (MPT), as assessed by either Ca(2+)-induced mitochondrial swelling, dissipation of membrane potential or mitochondrial Ca(2+) release. The Ca(2+) retention capacity of the liver mitochondria isolated from 3-month-old NAR was about 50% that of the control. Interestingly, the assessment of this variable in 21-day-old NAR indicated that the mitochondrial Ca(2+) retention capacity was preserved at this age, as compared to age-matched controls, which indicates that a reduced capacity for mitochondrial Ca(2+) retention is not a constitutive feature. The search for putative mediators of MPT sensitization in NAR revealed a 20% decrease in mitochondrial nitrosothiol content and a 30% increase in cyclophilin D expression. However, the evaluation of other variables related to mitochondrial redox status showed similar results between the controls and NAR, i.e., namely the contents of reduced mitochondrial membrane protein thiol groups and total glutathione, H(2)O(2) release rate, and NAD(P)H reduced state. We conclude that the higher expression of cyclophilin D, a major component of the MPT pore, and decreased nitrosothiol content in NAR mitochondria may underlie MPT sensitization in these animals.
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Affiliation(s)
- Tiago R Figueira
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil
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The anti-cancer agent nemorosone is a new potent protonophoric mitochondrial uncoupler. Mitochondrion 2010; 11:255-63. [PMID: 21044702 DOI: 10.1016/j.mito.2010.10.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 10/01/2010] [Accepted: 10/19/2010] [Indexed: 02/07/2023]
Abstract
Nemorosone, a natural-occurring polycyclic polyprenylated acylphloroglucinol, has received increasing attention due to its strong in vitro anti-cancer action. Here, we have demonstrated the toxic effect of nemorosone (1-25 μM) on HepG2 cells by means of the MTT assay, as well as early mitochondrial membrane potential dissipation and ATP depletion in this cancer cell line. In mitochondria isolated from rat liver, nemorosone (50-500 nM) displayed a protonophoric uncoupling activity, showing potency comparable to the classic protonophore, carbonyl cyanide m-chlorophenyl hydrazone (CCCP). Nemorosone enhanced the succinate-supported state 4 respiration rate, dissipated mitochondrial membrane potential, released Ca(2+) from Ca(2+)-loaded mitochondria, decreased Ca(2+) uptake and depleted ATP. The protonophoric property of nemorosone was attested by the induction of mitochondrial swelling in hyposmotic K(+)-acetate medium in the presence of valinomycin. In addition, uncoupling concentrations of nemorosone in the presence of Ca(2+) plus ruthenium red induced the mitochondrial permeability transition process. Therefore, nemorosone is a new potent protonophoric mitochondrial uncoupler and this property is potentially involved in its toxicity on cancer cells.
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22
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Paim BA, Velho JA, Castilho RF, Oliveira HCF, Vercesi AE. Oxidative stress in hypercholesterolemic LDL (low-density lipoprotein) receptor knockout mice is associated with low content of mitochondrial NADP-linked substrates and is partially reversed by citrate replacement. Free Radic Biol Med 2008; 44:444-51. [PMID: 17991444 DOI: 10.1016/j.freeradbiomed.2007.10.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 09/18/2007] [Accepted: 10/08/2007] [Indexed: 12/01/2022]
Abstract
We have previously proposed that hypercholesterolemic LDL receptor knockout (k/o) mice mitochondria possess a lower antioxidant capacity due to a large consumption of reducing equivalents from NADPH to sustain high rates of lipogenesis. In this work, we tested the hypothesis that this k/o mice mitochondrial oxidative stress results from the depletion of NADPH-linked substrates. In addition, the oxidative stress was further characterized by showing a lower mitochondrial GSH/GSSG ratio and a higher liver content of protein carbonyls as compared to controls. The activity of the antioxidant enzyme system glutathione reductase/peroxidase did not differ in k/o and control mitochondria. The faster spontaneous oxidation of endogenous NADPH in the k/o mitochondria was prevented by the addition of exogenous catalase, indicating that this oxidation is mediated by mitochondrially generated H(2)O(2). The higher rate of H(2)O(2) production was also prevented by the addition of exogenous isocitrate that maintains NADP fully reduced. The hypothesis that high rates of lipogenesis in the k/o cells decrease mitochondrial NADPH/NADP(+) ratio due to consumption of NADPH-linked substrates was supported by two findings: (i) oxygen consumption supported by endogenous NAD(P)H-linked substrates was slower in k/o than in control mitochondria, but was similar in the presence of exogenous isocitrate; (ii) in vivo treatment of k/o mice with sodium citrate/citric acid drinking solution for 2 weeks partially restored both the rate of oxygen consumption supported by NAD(P)H-linked substrates and the mitochondrial capacity to sustain reduced NADPH. In conclusion, the data demonstrate that the mitochondrial oxidative stress in hypercholesterolemic LDL receptor knockout mice is the result of a low content of mitochondrial NADPH-linked substrates in the intact animal that can be, at least in part, replenished by oral administration of citrate.
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Affiliation(s)
- Bruno A Paim
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-887, Campinas, SP, Brazil
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Oliveira HCF, Cosso RG, Alberici LC, Maciel EN, Salerno AG, Dorighello GG, Velho JA, de Faria EC, Vercesi AE. Oxidative stress in atherosclerosis‐prone mouse is due to low antioxidant capacity of mitochondria. FASEB J 2004; 19:278-80. [PMID: 15569776 DOI: 10.1096/fj.04-2095fje] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Atherosclerotic disease remains a leading cause of death in westernized societies, and reactive oxygen species (ROS) play a pivotal role in atherogenesis. Mitochondria are the main intracellular sites of ROS generation and are also targets for oxidative damage. Here, we show that mitochondria from atherosclerosis-prone, hypercholesterolemic low-density lipoprotein (LDL) receptor knockout mice have oxidative phosphorylation efficiency similar to that from control mice but have a higher net production of ROS and susceptibility to develop membrane permeability transition. Increased ROS production was observed in mitochondria isolated from several tissues, including liver, heart, and brain, and in intact mononuclear cells from spleen. In contrast to control mitochondria, knockout mouse mitochondria did not sustain a reduced state of matrix NADPH, the main source of antioxidant defense against ROS. Experiments in vivo showed faster liver secretion rates and de novo synthesis of triglycerides and cholesterol in knockout than in control mice, suggesting that increased lipogenesis depleted the reducing equivalents from NADPH and generated a state of oxidative stress in hypercholesterolemic knockout mice. These data provide the first evidence of how oxidative stress is generated in LDL receptor defective cells and could explain the increased LDL oxidation, cell death, and atherogenesis seen in familiar hypercholesterolemia.
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Maciel EN, Vercesi AE, Castilho RF. Oxidative stress in Ca(2+)-induced membrane permeability transition in brain mitochondria. J Neurochem 2001; 79:1237-45. [PMID: 11752064 DOI: 10.1046/j.1471-4159.2001.00670.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mitochondrial permeability transition (PT) is a non-selective inner membrane permeabilization, typically promoted by the accumulation of excessive quantities of Ca(2+) ions in the mitochondrial matrix. This phenomenon may contribute to neuronal cell death under some circumstances, such as following brain trauma and hypoglycemia. In this report, we show that Ca(2+)-induced brain mitochondrial PT was stimulated by Na(+) (10 mM) and totally prevented by the combination of ADP and cyclosporin A. Removal of Ca(2+) from the mitochondrial suspension by EGTA or inhibition of Ca(2+) uptake by ruthenium red partially reverted the dissipation of the membrane potential associated with PT. Ca(2+)-induced brain mitochondrial PT was significantly inhibited by the antioxidant catalase, indicating the participation of reactive oxygen species in this process. An increased detection of reactive oxygen species, measured through dichlorodihydrofluorescein oxidation, was observed after mitochondrial Ca(2+) uptake. Ca(2+)-induced dichlorodihydrofluorescein oxidation was enhanced by Na(+) and prevented by ADP and cyclosporin A, indicating that PT enhances mitochondrial oxidative stress. This could be at least in part a consequence of the extensive depletion in NAD(P)H that accompanied this Ca(2+)-induced mitochondrial PT. NADPH is known to maintain the antioxidant function of the glutathione reductase/peroxidase and thioredoxin reductase/peroxidase systems. In addition, the occurrence of mitochondrial PT was associated with membrane lipid peroxidation. We conclude that PT further increases Ca(2+)-induced oxidative stress in brain mitochondria leading to secondary damage such as lipid peroxidation.
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Affiliation(s)
- E N Maciel
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, Brazil
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25
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Abstract
Mitochondrial permeability transition (MPT) is a non-selective inner membrane permeabilization that may precede necrotic and apoptotic cell death. Although this process has a specific inhibitor, cyclosporin A, little is known about the nature of the proteinaceous pore that results in MPT. Here, we review data indicating that MPT is not a consequence of the opening of a pre-formed pore, but the consequence of oxidative damage to pre-existing membrane proteins.
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Affiliation(s)
- A J Kowaltowski
- Departamento de Bioquímica, Instituto de Quimica, Universidade de São Paulo, São Paulo, SP, Brazil
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26
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Zago EB, Castilho RF, Vercesi AE. The redox state of endogenous pyridine nucleotides can determine both the degree of mitochondrial oxidative stress and the solute selectivity of the permeability transition pore. FEBS Lett 2000; 478:29-33. [PMID: 10922464 DOI: 10.1016/s0014-5793(00)01815-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Acetoacetate, an NADH oxidant, stimulated the ruthenium red-insensitive rat liver mitochondrial Ca(2+) efflux without significant release of state-4 respiration, disruption of membrane potential (Deltapsi) or mitochondrial swelling. This process is compatible with the opening of the currently designated low conductance state of the permeability transition pore (PTP) and, under our experimental conditions, was associated with a partial oxidation of the mitochondrial pyridine nucleotides. In contrast, diamide, a thiol oxidant, induced a fast mitochondrial Ca(2+) efflux associated with a release of state-4 respiration, a disruption of Deltapsi and a large amplitude mitochondrial swelling. This is compatible with the opening of the high conductance state of the PTP and was associated with extensive oxidation of pyridine nucleotides. Interestingly, the addition of carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone to the acetoacetate experiment promoted a fast shift from the low to the high conductance state of the PTP. Both acetoacetate and diamide-induced mitochondrial permeabilization were inhibited by exogenous catalase. We propose that the shift from a low to a high conductance state of the PTP can be promoted by the oxidation of NADPH. This impairs the antioxidant function of the glutathione reductase/peroxidase system, strongly strengthening the state of mitochondrial oxidative stress.
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Affiliation(s)
- E B Zago
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-970, SP, Campinas, Brazil
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27
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Catisti R, Vercesi AE. The participation of pyridine nucleotides redox state and reactive oxygen in the fatty acid-induced permeability transition in rat liver mitochondria. FEBS Lett 1999; 464:97-101. [PMID: 10611491 DOI: 10.1016/s0014-5793(99)01677-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ability of low concentrations (5-15 microM) of long-chain fatty acids to open the permeability transition pore (PTP) in Ca(2+)-loaded mitochondria has been ascribed to their protonophoric effect mediated by mitochondrial anion carriers, as well as to a direct interaction with the pore assembly [M.R. Wieckowski and L. Wojtczak, FEBS Lett. 423 (1998) 339-342]. Here, we have compared the PTP opening ability of arachidonic acid (AA) with that of carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP) at concentrations that cause similar quantitative dissipation of the membrane potential (DeltaPsi) in Ca(2+)-loaded rat liver mitochondria respiring on succinate. The initial protonophoric effects of AA and FCCP were only slightly modified by carboxyatractyloside and were followed by PTP opening, as indicated by a second phase of DeltaPsi disruption sensitive to EGTA, ADP, dithiothreitol and cyclosporin A. This second phase of DeltaPsi dissipation could also be prevented by rotenone or NAD(P)H-linked substrates which decrease the pyridine nucleotide (PN) oxidation that follows the stimulation of oxygen consumption induced by AA or FCCP. These results suggest that, under the experimental conditions used here, the PTP opening induced by AA or FCCP was a consequence of PN oxidation. Exogenous catalase also inhibited both AA- and FCCP-induced PTP opening. These results indicate that a condition of oxidative stress associated with the oxidized state of PN underlies membrane protein thiol oxidation and PTP opening.
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Affiliation(s)
- R Catisti
- Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, 13083-970, Campinas, Brazil
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28
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Abstract
This review provides a selective history of how studies of mitochondrial cation transport (K+, Na+, Ca2+) developed in relation to the major themes of research in bioenergetics. It then covers in some detail specific transport pathways for these cations, and it introduces and discusses open problems about their nature and physiological function, particularly in relation to volume regulation and Ca2+ homeostasis. The review should provide the basic elements needed to understand both earlier mitochondrial literature and current problems associated with mitochondrial transport of cations and hopefully will foster new interest in the molecular definition of mitochondrial cation channels and exchangers as well as their roles in cell physiology.
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Affiliation(s)
- P Bernardi
- Department of Biomedical Sciences, University of Padova, and Consiglio Nazionale delle Ricerche Center for the Study of Biomembranes, Padova, Italy.
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29
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Du G, Mouithys-Mickalad A, Sluse FE. Generation of superoxide anion by mitochondria and impairment of their functions during anoxia and reoxygenation in vitro. Free Radic Biol Med 1998; 25:1066-74. [PMID: 9870560 DOI: 10.1016/s0891-5849(98)00148-8] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A small portion of the oxygen consumed by aerobic cells is converted to superoxide anion at the level of the mitochondrial respiratory chain. If produced in excess, this harmful radical is considered to impair cellular structures and functions. Damage at the level of mitochondria have been reported after ischemia and reperfusion of organs. However, the complexity of the in vivo system prevents from understanding and describing precise mechanisms and locations of mitochondrial impairment. An in vitro model of isolated-mitochondria anoxia-reoxygenation is used to investigate superoxide anion generation together with specific damage at the level of mitochondrial oxidative phosphorylation. Superoxide anion is detected by electron paramagnetic resonance spin trapping with POBN-ethanol. Mitochondrial respiratory parameters are calculated from oxygen consumption traces recorded with a Clark electrode. Respiring mitochondria produce superoxide anion in unstressed conditions, however, the production is raised during postanoxic reoxygenation. Several respiratory parameters are impaired after reoxygenation, as shown by decreases of phosphorylating and uncoupled respiration rates and of ADP/O ratio and by increase of resting respiration. Partial protection of mitochondrial function by POBN suggests that functional damage is related and secondary to superoxide anion production by the mitochondria in vitro.
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Affiliation(s)
- G Du
- Laboratory of Bioenergetics, Oxygen Biochemistry Center, University of Liege, Belgium
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30
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Kowaltowski AJ, Castilho RF, Vercesi AE. Opening of the mitochondrial permeability transition pore by uncoupling or inorganic phosphate in the presence of Ca2+ is dependent on mitochondrial-generated reactive oxygen species. FEBS Lett 1996; 378:150-2. [PMID: 8549822 DOI: 10.1016/0014-5793(95)01449-7] [Citation(s) in RCA: 198] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In this study, we show that mitochondrial membrane permeability transition in Ca(2+)-loaded mitochondria treated with carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) or inorganic phosphate (P(i)) is preceded by enhanced production of H2O2. This production is inhibited either by ethylene glycobis(b-aminoethyl ether)N,N,N',N'-tetraacetic acid (EGTA) or Mg2+, but not by cyclosporin A. Permeability transition is prevented either by EGTA, catalase or dithiothreitol, suggesting the involvement of Ca2+, H2O2 and oxidation of membrane protein thiols in this mechanism. When mitochondria are incubated under anaerobiosis, no permeabilization or H2O2 production occurs. Based on these results we conclude that mitochondrial permeability transition induced by P(i) or FCCP-uncoupling is dependent on mitochondrial-generated reactive oxygen species.
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Affiliation(s)
- A J Kowaltowski
- Departamento de Bioquimica, I.B., UNICAMP, Campinas, SP, Brasil
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31
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Sharma SK, Bhattacharya BK. Altered glycine transport by cerebral tissue and decreased Na+ and Ca++ pump activities during organophosphorus-ester-induced delayed neurotoxicity development period. JOURNAL OF BIOCHEMICAL TOXICOLOGY 1995; 10:233-238. [PMID: 8847704 DOI: 10.1002/jbt.2570100502] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Uptake of [U-14C] glycine during the organophosphorus-ester-induced delayed neurotoxicity (OPIDN) development period was studied. Diisopropyl fluorophosphate (DFP), a delayed neurotoxic organophosphorus ester was administered to adult rats and hens. Results showed a decreased accumulation of glycine in hen cerebral cortex slices during the delayed neurotoxicity development period. An altered sensitivity toward transport inhibitors 2,4-dinitrophenol and ouabain was observed in DFP-treated hens. An altered neuronal membrane function during the OPIDN development period is reported in the present work. Brain Na+, K(+)-ATPase and Ca(++)-ATPase activities decreased during the neurotoxicity development period. The decrease in Ca(++)-ATPase activity persisted in hens until the complete development of neurotoxic symptoms. Decreased Ca++ pump activity is correlated with altered membrane function during OPIDN.
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Affiliation(s)
- S K Sharma
- Biochemistry Division, Defence Research and Development Establishment, Gwalior, India
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32
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Affiliation(s)
- M Zoratti
- CNR Unit for the Physiology of Mitochondria, Department of Biomedical Sciences, Padova, Italy
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33
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Vamvakas S, Bittner D, Dekant W, Anders MW. Events that precede and that follow S-(1,2-dichlorovinyl)-L-cysteine-induced release of mitochondrial Ca2+ and their association with cytotoxicity to renal cells. Biochem Pharmacol 1992; 44:1131-8. [PMID: 1417936 DOI: 10.1016/0006-2952(92)90377-u] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Previous studies showed that S-(1,2-dichlorovinyl)-L-cysteine perturbs intracellular Ca2+ homeostasis [Vamvakas et al., Mol Pharmacol 38: 455-461, 1990]. The objective of the present study was to investigate the cellular events that precede and that follow S-(1,2-dichlorovinyl)-L-cysteine-induced mitochondrial Ca2+ release. In incubations with isolated kidney mitochondria, S-(1,2-dichlorovinyl)-L-cysteine-induced Ca2+ efflux is preceded by increased oxidation of mitochondrial pyridine nucleotides and is prevented by ATP, an inhibitor of the hydrolysis of pyridine nucleotides, and by meta-iodobenzylguanidine, an acceptor of ADP-ribose moieties. In LLC-PK1 cells, elevation in the cytosolic Ca2+ concentration is followed by a several-fold increase in DNA double-strand breaks which is attributed to the activation of Ca2+- and Mg(2+)-dependent endonucleases. The formation of DNA double-strand breaks is followed by increased poly(ADP-ribosylation) of nuclear proteins. S-(1,2-Dichlorovinyl)-L-cysteine-induced cytotoxicity in LLC-PK1 cells is blocked by chelation of cytosolic Ca2+ with Quin-2, by inhibition of DNA fragmentation with aurintricarboxylic acid and by inhibition of increased poly(ADP-ribosyl)transferase activity by 3-aminobenzamide. These findings indicate that S-(1,2-dichlorovinyl)-L-cysteine bioactivation in renal cells may initiate the following cascade of events: increased oxidation and hydrolysis of mitochondrial pyridine nucleotides resulting in the modification of mitochondrial membrane proteins by pyridine nucleotide-derived ADP-ribose moieties, followed by Ca2+ release. Elevated Ca2+ concentrations may activate Ca(2+)-dependent endonucleases, which leads to DNA fragmentation followed by increased poly(ADP-ribosylation) of nuclear proteins and, finally, cytotoxicity.
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Affiliation(s)
- S Vamvakas
- Institut für Toxikologie, Universität Würzburg, Germany
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34
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Lenartowicz E. A complex effect of arsenite on the formation of alpha-ketoglutarate in rat liver mitochondria. Arch Biochem Biophys 1990; 283:388-96. [PMID: 2275550 DOI: 10.1016/0003-9861(90)90659-m] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
This investigation presents disturbances of the mitochondrial metabolism by arsenite, a hydrophilic dithiol reagent known as an inhibitor of mitochondrial alpha-keto acid dehydrogenases. Arsenite at concentrations of 0.1-1.0 mM was shown to induce a considerable oxidation of intramitochondrial NADPH, NADH, and glutathione without decreasing the mitochondrial membrane potential. The oxidation of NAD(P)H required the presence of phosphate and was sensitive to ruthenium red, but occurred without the addition of calcium salts. Mitochondrial reactions producing alpha-ketoglutarate from glutamate and isocitrate were modulated by arsenite through various mechanisms: (i) both glutamate transaminations, with oxaloacetate and with pyruvate, were inhibited by accumulating alpha-ketoglutarate; however, at low concentrations of alpha-ketoglutarate the aspartate aminotransferase reaction was stimulated due to the increase of NAD+ content; (ii) the oxidation of isocitrate was stimulated at its low concentration only, due to the oxidation of NADPH and NADH; this oxidation was prevented by concentrations of citrate or isocitrate greater than 1 mM; (iii) the conversion of isocitrate to citrate was suppressed, presumably as a result of the decrease of Mg2+ concentration in mitochondria. Thus the depletion of mitochondrial vicinal thiol groups in hydrophilic domains disturbs the mitochondrial metabolism not only by the inhibition of alpha-keto acid dehydrogenases but also by the oxidation of NAD(P)H and, possibly, by the change in the ion concentrations.
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Affiliation(s)
- E Lenartowicz
- Department of Cellular Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
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35
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Membrane protein thiol cross-linking associated with the permeabilization of the inner mitochondrial membrane by Ca2+ plus prooxidants. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(17)45467-6] [Citation(s) in RCA: 154] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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36
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Chávez E, Zazueta C, Díaz E. Dicyclohexylcarbodiimide as inducer of mitochondrial Ca2+ release. J Bioenerg Biomembr 1990; 22:679-89. [PMID: 2249979 DOI: 10.1007/bf00809071] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effect of the alkylating reagent dicyclohexylcarbodiimide (DCCD) on mitochondrial Ca2+ content was studied. The results obtained indicate that DCCD at a concentration of 100 microM induces mitochondrial Ca2+ efflux. This reaction is accompanied by an increasing energy drain on the system, stimulation of oxygen consumption, and mitochondrial swelling. These DCCD effects can be partially suppressed by supplementing the incubation medium with 1 mM phosphate. By electrophoretic analysis on polyacrylamide-sodium dodecyl sulfate, it was found that DCCD binds to a membrane component with an Mr of 20 to 29 kDa.
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Affiliation(s)
- E Chávez
- Departamento de Bioquímica, Instituto Nacional de Cardiología, D. F., Mexico
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37
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Hallberg E. Metabolism and toxicity of xenobiotics in the adrenal cortex, with particular reference to 7,12-dimethylbenz(a)anthracene. JOURNAL OF BIOCHEMICAL TOXICOLOGY 1990; 5:71-90. [PMID: 2126560 DOI: 10.1002/jbt.2570050202] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The adrenal cortex contains high amounts of detoxifying enzymes, as well as generators and protectors of reactive oxygen species. The high content of cytochrome P-450 enzymes in the adrenal cortex together with its remarkable tendency to accumulate hydrophobic substances probably contributes to the extraordinary vulnerability of the gland to a number of xenobiotics. The best studied adrenocorticolytic compounds are the potent carcinogen 7,12-dimethylbenz(a)anthracene (DMBA) and its liver metabolite 7-hydroxymethyl-12-methylbenz(a)anthracene (7-OHM-12-MBA). Adrenocorticolysis generated by these agents in vivo as well as in vitro demonstrates high regioselective requirements and is strongly influenced by the presence of ACTH, steroids, cytochrome P-450 inhibitors and antioxidants. Furthermore, 7-OHM-12-MBA has been demonstrated to uniquely generate selective and massive oxidation of mitochondrial glutathione in cultured rat adrenal cells. The DMBA-induced adrenocorticolysis is thoroughly discussed in this review with particular emphasis on the metabolism of DMBA and the influence of various effectors. A working hypothesis involving a possible peroxidative mechanism is also presented.
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Affiliation(s)
- E Hallberg
- Department of Biochemistry, Arrhenius Laboratory, University of Stockholm, Sweden
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38
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Mansurova SE. Inorganic pyrophosphate in mitochondrial metabolism. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 977:237-47. [PMID: 2556179 DOI: 10.1016/s0005-2728(89)80078-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- S E Mansurova
- A.N. Belozersky Laboratory of Molecular Biology, Moscow State University, U.S.S.R
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39
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Chávez E, Zazueta C, Díaz E, Holquín JA. Characterization by Hg2+ of two different pathways for mitochondrial Ca2+ release. BIOCHIMICA ET BIOPHYSICA ACTA 1989; 986:27-32. [PMID: 2819096 DOI: 10.1016/0005-2736(89)90268-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The addition of Hg2+ to loaded kidney mitochondria induces the fast release of the accumulated cation. The Ca2+-efflux reaction exhibits kinetics characteristics that depend on the extent of the binding of Hg2+ to the membrane. At high levels of Hg2+ bound (approx. 11 nmol/mg), Ca2+ efflux rate is highly insensitive to the temperature of incubation, and the efflux seems to be directly related to the internal free Ca2+ concentration. At these levels of bound Hg2+, accumulated Sr2+ is released with characteristics similar to those observed with Ca2+. At lower levels of Hg2+ binding (2.5 nmol/mg), the efflux reaction is highly dependent on the incubation temperature and on the internal free Ca2+ concentration; under these conditions Sr2+ is not released. NAD(P)H oxidation as induced by the low Hg2+ concentration is inhibited at the lower temperatures. Radiolabeled Hg2+ incorporates into two clearly defined regions of membrane proteins separated through sodium dodecyl sulfate gel electrophoresis. One of the regions corresponds to proteins of apparent high molecular mass (i.e., 150 kDa), and the other to proteins with apparent molecular masses of 37-25 kDa. Mitochondria incubated with 2 microM 203Hg2+ incorporate the radionuclide in proteins that have molecular masses of around 41 and 26 kDa. The results indicate that, depending on the amount of Hg2+ bound to the inner membrane, two clearly distinct Ca2+ release mechanisms can be distinguished.
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Affiliation(s)
- E Chávez
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Ignacio Chávez, Mexico City
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40
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Chávez E, Zazueta C, Bravo C. Extensive Ca2+ release from energized mitochondria induced by disulfiram. J Bioenerg Biomembr 1989; 21:335-45. [PMID: 2545669 DOI: 10.1007/bf00762725] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effect of the alcohol-deterrent drug, disulfiram, on mitochondrial Ca2+ content was studied. Addition of this drug (20 microM) to mitochondria induces a complete loss of accumulated Ca2+. The calcium release is accompanied by a collapse of the transmembrane potential, mitochondrial swelling, and a diminution of the NAD(P)H/NAD(P) radio. These effects of disulfiram depend on Ca2+ accumulation; thus, ruthenium red reestablished the membrane delta psi and prevents the oxidation of pyridine nucleotides. The binding of disulfiram to the membrane sulfhydryls appeared to depend on the metabolic state of mitochondria, as well as on the mitochondrial configuration. In addition, it is shown that modification of 9 nmol -SH groups per mg protein suffices to induce the release of accumulated Ca2+.
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Affiliation(s)
- E Chávez
- Departamento de Bioquímica Instituto Nacional de Cardiología, Ignacio Chávez, México
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41
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Hallberg E, Rydström J. Selective oxidation of mitochondrial glutathione in cultured rat adrenal cells and its relation to polycyclic aromatic hydrocarbon-induced cytotoxicity. Arch Biochem Biophys 1989; 270:662-71. [PMID: 2539778 DOI: 10.1016/0003-9861(89)90549-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Primary cultures of rat adrenal cells, as well as rat adrenals in vivo, are sensitive to the potent carcinogen 7,12-dimethylbenz[a]anthracene and its liver metabolite 7-hydroxymethyl-12-methylbenz[a]anthracene, whereas unmethylated polycyclic aromatic hydrocarbons like benzo[a]pyrene or benzo[a]anthracene are ineffective. The adrenocorticolytic potencies of the hydrocarbons are affected by adrenocorticotrophic hormone and various steroids, cytochrome P450 inhibitors, and antioxidants. In the present investigation digitonin was used to fractionate cultured rat adrenal cells. It was found that the mitochondria and cytosol of the cells contained 3-5 nmol/10(6) cells (approximately 15%) and 20-30 nmol/10(6) cells (approximately 85%) of the total soluble cellular glutathione equivalents, respectively. After exposing the cells to 7-hydroxymethyl-12-methylbenz[a]anthracene in the culture medium, a time- and concentration-dependent selective oxidation of mitochondrial glutathione was observed, whereas the effect on the cytosolic glutathione was negligible. Under the same conditions, 7,12-dimethylbenz[a]anthracene and benzo[a]pyrene were unable to alter the redox levels of the subcellular pools of glutathione. Omission of adrenocorticotrophic hormone lowered the oxidation of mitochondrial glutathione induced by 7-hydroxymethyl-12-methylbenz[a]anthracene about twofold. The results suggest that rat adrenal cells contain two separate pools of glutathione, one cytosolic and one mitochondrial, of which the latter is selectively influenced by 7-hydroxymethyl-12-methylbenz[a]anthracene. Moreover, it is concluded that rat adrenal cells offer a unique model system for general studies of the effects of a selective oxidation of mitochondrial glutathione on various cell functions. These effects may constitute early changes in cytotoxicity, preceding, e.g., membrane damage and loss of cytosolic components.
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Affiliation(s)
- E Hallberg
- Department of Biochemistry, Arrhenius Laboratory, University of Stockholm, Sweden
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42
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Moore GA, Weis M, Orrenius S, O'Brien PJ. Role of sulfhydryl groups in benzoquinone-induced Ca2+ release by rat liver mitochondria. Arch Biochem Biophys 1988; 267:539-50. [PMID: 3214168 DOI: 10.1016/0003-9861(88)90061-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Incubation of rat liver mitochondria with benzoquinone derivatives in the presence of succinate plus rotenone has been shown to cause NAD(P)H oxidation followed by Ca2+ release. Further investigation revealed: (1)p-Benzoquinone-induced Ca2+ release was not initiated by a collapse of the mitochondrial membrane potential. However, Ca2+ release and subsequent Ca2+ cycling caused limited increased membrane permeability. (2) p-Benzoquinone-induced NAD(P)H oxidation and Ca2+ release were prevented by isocitrate, 3-hydroxybutyrate, and glutamate but not by pyruvate or 2-oxoglutarate. (3) Inhibition of pyruvate and 2-oxoglutarate dehydrogenases by p-benzoquinone was attributed to arylation of the SH groups of the cofactors, CoA and lipoic acid. Isocitrate dehydrogenase was also inhibited by p-benzoquinone, but the cofactors NAD(P)H and Mn2+ protected the enzyme. Glutamate dehydrogenase was not inhibited by p-benzoquinone. (4) Arylation of mitochondrial protein thiols by p-benzoquinone was associated with an inhibition of state 3 respiration, which was attributed to the inactivation of the phosphate translocase. In contrast, state 4 respiration, and the F1.F0-ATPase and ATP/ADP translocase activities were not inhibited. It was concluded that inhibition of mitochondrial NAD(P)H dehydrogenases by arylation of critical thiol groups will decrease the NAD(P)+-reducing capacity, and possibly lower the NAD(P)H/NAD(P)+ redox status in favor of Ca2+ release.
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Affiliation(s)
- G A Moore
- Department of Toxicology, Karolinska Institutet, Stockholm, Sweden
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43
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Vercesi AE, Ferraz VL, Macedo DV, Fiskum G. Ca2+-dependent NAD(P)+-induced alterations of rat liver and hepatoma mitochondrial membrane permeability. Biochem Biophys Res Commun 1988; 154:934-41. [PMID: 3136771 DOI: 10.1016/0006-291x(88)90229-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Deenergized rat liver or AS-30D hepatoma mitochondria underwent extensive swelling when incubated in the presence of Ca2+ and an oxidant of mitochondrial pyridine nucleotides. This swelling was stimulated by phosphate and inhibited by ruthenium red, Mg2+ plus ATP and dibucaine. The degree of inhibition by dibucaine was shown to vary inversely with the Ca2+ concentration. The inhibition caused by ruthenium red was completely removed by the Ca2+ ionophore ionomycin indicating that the effect of the cation is mediated by internal binding sites. Since mitochondria were totally deenergized the data definitely rule out the requirement for Ca2+ cycling across the membrane in this mechanism.
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Affiliation(s)
- A E Vercesi
- Departamento de Bioquímica, I.B., Unicamp, Campinas, Brasil
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44
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Abstract
From the foregoing considerations, the energy-linked transhydrogenase reaction emerges as a powerful and flexible element in the network of redox and energy interrelationships that integrate mitochondrial and cytosolic metabolism. Its thermodynamic features make it possible for the reaction to respond readily to challenges, either on the side of NADPH utilization or on the side of energy depletion. Yet, the kinetic features are designed to prevent a wasteful input of energy when other sources of reducing equivalents to NADP are available, or to deplete the redox potential of NADPH in other than emergency conditions. By virtue of these characteristics, the energy-linked transhydrogenase can act as an effective buffer system, guarding against an excessive depletion of NADPH, preventing uncontrolled changes in key metabolites associated with NADP-dependent enzymes and calling on the supply of reducing equivalents from NAD-linked substrates only under conditions of high demand for NADPH. At the same time, it can provide an emergency protection against a depletion of energy, especially in situations of anoxia where a supply of reducing equivalents through NADP-linked substrates can be maintained. The flexibility of this design makes it possible that the functions of the energy-linked transhydrogenase vary from one tissue to another and are readily adjustable to different metabolic conditions.
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Affiliation(s)
- J B Hoek
- Department of Pathology and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107
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Moore GA, Rossi L, Nicotera P, Orrenius S, O'Brien PJ. Quinone toxicity in hepatocytes: studies on mitochondrial Ca2+ release induced by benzoquinone derivatives. Arch Biochem Biophys 1987; 259:283-95. [PMID: 3426229 DOI: 10.1016/0003-9861(87)90495-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Hepatocyte cytotoxicity caused by substituted benzoquinones was associated with increased cytosolic Ca2+ concentration. p-Benzoquinone-induced hepatotoxicity was enhanced when the hepatocytes were loaded with Ca2+ by preincubation with ATP. A similar order of potency of the substituted benzoquinones in releasing Ca2+ from isolated mitochondria and inducing hepatocyte cytotoxicity was found; in decreasing order, this was 2-Br-, unsubstituted-, 2-CH3-, 2,6-(CH3O)2-, 2,6-(CH3)2-, 2,5-(CH3)2-, 2,3,5-(CH3)3-, and 2,3,5,6-(CH3)4-benzoquinones (duroquinone). The cellular products of quinone metabolism, hydroquinones and glutathione conjugates, did not cause mitochondrial Ca2+ release. Benzoquinone-induced mitochondrial Ca2+ release was preceded by GSH conjugate formation and NAD(P)H oxidation but followed by mitochondrial swelling. With duroquinone, a slow GSH and NADPH oxidation preceded Ca2+ release, but GSH oxidation did not occur with Se-deficient mitochondria lacking glutathione peroxidase activity. Cyanide-insensitive respiration was also observed with duroquinone but not with benzoquinone, suggesting that duroquinone undergoes redox cycling. GSH was depleted by both arylation and oxidation with 2,6-(CH3O)2-, 2,6-(CH3)2-, 2,5(CH3)2-, and 2,3,5-(CH3)3-benzoquinones. Benzoquinone concentrations that totally depleted GSH did not cause Ca2+ release until intramitochondrial NAD(P)H was oxidized. Ca2+ release was also prevented when NAD(P)H generation was stimulated by the presence of isocitrate or 3-hydroxybutyrate. This suggests that mitochondrial Ca2+ release is associated with NAD(P)H oxidation catalyzed by NADH dehydrogenase with benzoquinone or by the glutathione peroxidase-glutathione reductase system with duroquinone.
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Affiliation(s)
- G A Moore
- Department of Toxicology, Karolinska Institutet, Stockholm, Sweden
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