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Role of Mitochondrial Transporters on Metabolic Rewiring of Pancreatic Adenocarcinoma: A Comprehensive Review. Cancers (Basel) 2023; 15:cancers15020411. [PMID: 36672360 PMCID: PMC9857038 DOI: 10.3390/cancers15020411] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/03/2023] [Accepted: 01/06/2023] [Indexed: 01/11/2023] Open
Abstract
Pancreatic cancer is among the deadliest cancers worldwide and commonly presents as pancreatic ductal adenocarcinoma (PDAC). Metabolic reprogramming is a hallmark of PDAC. Glucose and glutamine metabolism are extensively rewired in order to fulfil both energetic and synthetic demands of this aggressive tumour and maintain favorable redox homeostasis. The mitochondrial pyruvate carrier (MPC), the glutamine carrier (SLC1A5_Var), the glutamate carrier (GC), the aspartate/glutamate carrier (AGC), and the uncoupling protein 2 (UCP2) have all been shown to influence PDAC cell growth and progression. The expression of MPC is downregulated in PDAC and its overexpression reduces cell growth rate, whereas the other four transporters are usually overexpressed and the loss of one or more of them renders PDAC cells unable to grow and proliferate by altering the levels of crucial metabolites such as aspartate. The aim of this review is to comprehensively evaluate the current experimental evidence about the function of these carriers in PDAC metabolic rewiring. Dissecting the precise role of these transporters in the context of the tumour microenvironment is necessary for targeted drug development.
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Koufos O, Mailloux RJ. Protein S-glutathionylation and sex dimorphic effects on hydrogen peroxide production by dihydroorotate dehydrogenase in liver mitochondria. Free Radic Biol Med 2023; 194:123-130. [PMID: 36462627 DOI: 10.1016/j.freeradbiomed.2022.11.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/11/2022] [Accepted: 11/29/2022] [Indexed: 12/02/2022]
Abstract
Dihydroorotate dehydrogenase (DHODH) oxidizes dihydroorotate to orotate for pyrimidine biosynthesis, donating electrons to the ubiquinone (UQ) pool of mitochondria. DHODH has a measurable rate for hydrogen peroxide (H2O2) production and thus contributes to cellular changes in redox tone. Protein S-glutathionylation serves as a negative feedback loop for the inhibition of H2O2 by several α-keto acid dehydrogenases and respiratory complexes in mitochondria, as well as ROS sources in liver cytoplasm. Here, we report this redox signaling mechanism also inhibits H2O2 production by DHODH in liver mitochondria isolated from male and female C57BL6N mice. We discovered that low amounts of the glutathionylation catalyst, disulfiram (50-500 nM), almost abolished H2O2 production by DHODH in mitochondria from male mice. Similar results were collected with diamide, however, higher doses (1000-5000 μM) were required to elicit this effect. Disulfiram and diamide also significantly suppressed H2O2 production by DHODH in female liver mitochondria. However, liver mitochondria from female mice were more resistant to disulfiram or diamide-mediated inhibition of H2O2 genesis when compared to samples from males. Analysis of the impact of disulfiram and diamide on DHODH activity revealed that both compounds inhibited the dehydrogenase directly, however the effect was less in female mice. Additionally, disulfiram and diamide impeded the use of dihydroorotate fueled oxidative phosphorylation in mitochondria from males and females, although samples collected from female rodents displayed more resistance to this inhibition. Taken together, our findings demonstrate H2O2 production by DHODH can be inhibited by glutathionylation and sex can impact this redox modification.
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Affiliation(s)
- Olivia Koufos
- The School of Human Nutrition, Faculty of Agricultural and Environmental Sciences, McGill University, Ste.-Anne-de-Bellevue, Quebec, Canada
| | - Ryan J Mailloux
- The School of Human Nutrition, Faculty of Agricultural and Environmental Sciences, McGill University, Ste.-Anne-de-Bellevue, Quebec, Canada.
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Regulation of Mitochondrial Hydrogen Peroxide Availability by Protein S-glutathionylation. Cells 2022; 12:cells12010107. [PMID: 36611901 PMCID: PMC9818751 DOI: 10.3390/cells12010107] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/23/2022] [Accepted: 12/24/2022] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND It has been four decades since protein S-glutathionylation was proposed to serve as a regulator of cell metabolism. Since then, this redox-sensitive covalent modification has been identified as a cell-wide signaling platform required for embryonic development and regulation of many physiological functions. SCOPE OF THE REVIEW Mitochondria use hydrogen peroxide (H2O2) as a second messenger, but its availability must be controlled to prevent oxidative distress and promote changes in cell behavior in response to stimuli. Experimental data favor the function of protein S-glutathionylation as a feedback loop for the inhibition of mitochondrial H2O2 production. MAJOR CONCLUSIONS The glutathione pool redox state is linked to the availability of H2O2, making glutathionylation an ideal mechanism for preventing oxidative distress whilst playing a part in desensitizing mitochondrial redox signals. GENERAL SIGNIFICANCE The biological significance of glutathionylation is rooted in redox status communication. The present review critically evaluates the experimental evidence supporting its role in negating mitochondrial H2O2 production for cell signaling and prevention of electrophilic stress.
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Glutamine-Derived Aspartate Biosynthesis in Cancer Cells: Role of Mitochondrial Transporters and New Therapeutic Perspectives. Cancers (Basel) 2022; 14:cancers14010245. [PMID: 35008407 PMCID: PMC8750728 DOI: 10.3390/cancers14010245] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/30/2021] [Accepted: 01/01/2022] [Indexed: 12/20/2022] Open
Abstract
Simple Summary In recent years, aspartate has been increasingly acknowledged as a critical player in the metabolism of cancer cells which use this metabolite for nucleotide and protein synthesis and for redox homeostasis. Most intracellular aspartate derives from the mitochondrial catabolism of glutamine. To date at least four mitochondrial transporters have been involved in this metabolic pathway. Their involvement appears to be cancer type-specific and dependent on glutamine availability. Targeting these mitochondrial transporters may represent a new attractive strategy to fight cancer. The aim of this review is to dissect the role of each of these transporters in relation to the type of cancer and the availability of nutrients in the tumoral microenvironment. Abstract Aspartate has a central role in cancer cell metabolism. Aspartate cytosolic availability is crucial for protein and nucleotide biosynthesis as well as for redox homeostasis. Since tumor cells display poor aspartate uptake from the external environment, most of the cellular pool of aspartate derives from mitochondrial catabolism of glutamine. At least four transporters are involved in this metabolic pathway: the glutamine (SLC1A5_var), the aspartate/glutamate (AGC), the aspartate/phosphate (uncoupling protein 2, UCP2), and the glutamate (GC) carriers, the last three belonging to the mitochondrial carrier family (MCF). The loss of one of these transporters causes a paucity of cytosolic aspartate and an arrest of cell proliferation in many different cancer types. The aim of this review is to clarify why different cancers have varying dependencies on metabolite transporters to support cytosolic glutamine-derived aspartate availability. Dissecting the precise metabolic routes that glutamine undergoes in specific tumor types is of upmost importance as it promises to unveil the best metabolic target for therapeutic intervention.
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Shrestha R, Johnson E, Byrne FL. Exploring the therapeutic potential of mitochondrial uncouplers in cancer. Mol Metab 2021; 51:101222. [PMID: 33781939 PMCID: PMC8129951 DOI: 10.1016/j.molmet.2021.101222] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/17/2021] [Accepted: 03/23/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Mitochondrial uncouplers are well-known for their ability to treat a myriad of metabolic diseases, including obesity and fatty liver diseases. However, for many years now, mitochondrial uncouplers have also been evaluated in diverse models of cancer in vitro and in vivo. Furthermore, some mitochondrial uncouplers are now in clinical trials for cancer, although none have yet been approved for the treatment of cancer. SCOPE OF REVIEW In this review we summarise published studies in which mitochondrial uncouplers have been investigated as an anti-cancer therapy in preclinical models. In many cases, mitochondrial uncouplers show strong anti-cancer effects both as single agents, and in combination therapies, and some are more toxic to cancer cells than normal cells. Furthermore, the mitochondrial uncoupling mechanism of action in cancer cells has been described in detail, with consistencies and inconsistencies between different structural classes of uncouplers. For example, many mitochondrial uncouplers decrease ATP levels and disrupt key metabolic signalling pathways such as AMPK/mTOR but have different effects on reactive oxygen species (ROS) production. Many of these effects oppose aberrant phenotypes common in cancer cells that ultimately result in cell death. We also highlight several gaps in knowledge that need to be addressed before we have a clear direction and strategy for applying mitochondrial uncouplers as anti-cancer agents. MAJOR CONCLUSIONS There is a large body of evidence supporting the therapeutic use of mitochondrial uncouplers to treat cancer. However, the long-term safety of some uncouplers remains in question and it will be critical to identify which patients and cancer types would benefit most from these agents.
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Affiliation(s)
- Riya Shrestha
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, 2052, Australia
| | - Edward Johnson
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, 2052, Australia
| | - Frances L Byrne
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, 2052, Australia.
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Role of protein S-Glutathionylation in cancer progression and development of resistance to anti-cancer drugs. Arch Biochem Biophys 2021; 704:108890. [PMID: 33894196 DOI: 10.1016/j.abb.2021.108890] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/16/2022]
Abstract
The survival, functioning and proliferation of mammalian cells are highly dependent on the cellular response and adaptation to changes in their redox environment. Cancer cells often live in an altered redox environment due to aberrant neo-vasculature, metabolic reprogramming and dysregulated proliferation. Thus, redox adaptations are critical for their survival. Glutathione plays an essential role in maintaining redox homeostasis inside the cells by binding to redox-sensitive cysteine residues in proteins by a process called S-glutathionylation. S-Glutathionylation not only protects the labile cysteine residues from oxidation, but also serves as a sensor of redox status, and acts as a signal for stimulation of downstream processes and adaptive responses to ensure redox equilibrium. The present review aims to provide an updated overview of the role of the unique redox adaptations during carcinogenesis and cancer progression, focusing on their dependence on S-glutathionylation of specific redox-sensitive proteins involved in a wide range of processes including signalling, transcription, structural maintenance, mitochondrial functions, apoptosis and protein recycling. We also provide insights into the role of S-glutathionylation in the development of resistance to chemotherapy. Finally, we provide a strong rationale for the development of redox targeting drugs for treatment of refractory/resistant cancers.
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Panina SB, Pei J, Kirienko NV. Mitochondrial metabolism as a target for acute myeloid leukemia treatment. Cancer Metab 2021; 9:17. [PMID: 33883040 PMCID: PMC8058979 DOI: 10.1186/s40170-021-00253-w] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/30/2021] [Indexed: 02/06/2023] Open
Abstract
Acute myeloid leukemias (AML) are a group of aggressive hematologic malignancies resulting from acquired genetic mutations in hematopoietic stem cells that affect patients of all ages. Despite decades of research, standard chemotherapy still remains ineffective for some AML subtypes and is often inappropriate for older patients or those with comorbidities. Recently, a number of studies have identified unique mitochondrial alterations that lead to metabolic vulnerabilities in AML cells that may present viable treatment targets. These include mtDNA, dependency on oxidative phosphorylation, mitochondrial metabolism, and pro-survival signaling, as well as reactive oxygen species generation and mitochondrial dynamics. Moreover, some mitochondria-targeting chemotherapeutics and their combinations with other compounds have been FDA-approved for AML treatment. Here, we review recent studies that illuminate the effects of drugs and synergistic drug combinations that target diverse biomolecules and metabolic pathways related to mitochondria and their promise in experimental studies, clinical trials, and existing chemotherapeutic regimens.
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Affiliation(s)
| | - Jingqi Pei
- Department of BioSciences, Rice University, Houston, TX, USA
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Role of Glutathione in Cancer: From Mechanisms to Therapies. Biomolecules 2020; 10:biom10101429. [PMID: 33050144 PMCID: PMC7600400 DOI: 10.3390/biom10101429] [Citation(s) in RCA: 318] [Impact Index Per Article: 79.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/30/2020] [Accepted: 10/04/2020] [Indexed: 12/17/2022] Open
Abstract
Glutathione (GSH) is the most abundant non-protein thiol present at millimolar concentrations in mammalian tissues. As an important intracellular antioxidant, it acts as a regulator of cellular redox state protecting cells from damage caused by lipid peroxides, reactive oxygen and nitrogen species, and xenobiotics. Recent studies have highlighted the importance of GSH in key signal transduction reactions as a controller of cell differentiation, proliferation, apoptosis, ferroptosis and immune function. Molecular changes in the GSH antioxidant system and disturbances in GSH homeostasis have been implicated in tumor initiation, progression, and treatment response. Hence, GSH has both protective and pathogenic roles. Although in healthy cells it is crucial for the removal and detoxification of carcinogens, elevated GSH levels in tumor cells are associated with tumor progression and increased resistance to chemotherapeutic drugs. Recently, several novel therapies have been developed to target the GSH antioxidant system in tumors as a means for increased response and decreased drug resistance. In this comprehensive review we explore mechanisms of GSH functionalities and different therapeutic approaches that either target GSH directly, indirectly or use GSH-based prodrugs. Consideration is also given to the computational methods used to describe GSH related processes for in silico testing of treatment effects.
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9
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Olivas-Aguirre M, Pottosin I, Dobrovinskaya O. Mitochondria as emerging targets for therapies against T cell acute lymphoblastic leukemia. J Leukoc Biol 2019; 105:935-946. [PMID: 30698851 DOI: 10.1002/jlb.5vmr0818-330rr] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 01/11/2019] [Accepted: 01/12/2019] [Indexed: 12/29/2022] Open
Abstract
Acute lymphoblastic leukemia (ALL) comprises a heterogeneous group of hematologic malignancies, arising from diverse genetic alterations in the early lymphocyte development. T-cell subtype of ALL (T-ALL) accounts for about 15% and 25% of ALL in children and adults, respectively. Being less frequent among ALL subtypes, T-ALL represents a high-risk factor for poor prognosis due to its aggressiveness and resistance to common antileukemic drugs. Mitochondria were widely explored recently as a target for anticancer treatment because they are involved in a metabolic reprogramming of a cancer cell and play key roles in reactive oxygen species generation, Ca2+ signaling, and cell death induction. Accordingly, a new class of anticancer compounds named mitocans has been developed, which target mitochondria at distinct crucial points to promote their dysfunction and subsequent cell death. The present review analyses the role of mitochondria in malignant reprogramming and emerging therapeutic strategies targeting mitochondria as an "Achilles' heel" in T-ALL, with an emphasis on BH3 mimetics, sequestering pro-survival BCL proteins and voltage-dependent anion channel (VDAC)1-directed drugs, which promote the suppression of aerobic glycolysis, VDAC1 closure, mitochondrial Ca2+ overload, stoppage of the oxidative phosphorylation, oxidative stress, and release of proapoptotic factors.
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Affiliation(s)
- Miguel Olivas-Aguirre
- Laboratory of Immunobiology and Ionic Transport Regulation, University Center for Biomedical Research, University of Colima, Colima, Mexico
| | - Igor Pottosin
- Laboratory of Immunobiology and Ionic Transport Regulation, University Center for Biomedical Research, University of Colima, Colima, Mexico
| | - Oxana Dobrovinskaya
- Laboratory of Immunobiology and Ionic Transport Regulation, University Center for Biomedical Research, University of Colima, Colima, Mexico
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Mailloux RJ. Cysteine Switches and the Regulation of Mitochondrial Bioenergetics and ROS Production. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1158:197-216. [PMID: 31452142 DOI: 10.1007/978-981-13-8367-0_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Mitochondria are dynamic organelles that perform a number of interconnected tasks that are elegantly intertwined with the regulation of cell functions. This includes the provision of ATP, reactive oxygen species (ROS), and building blocks for the biosynthesis of macromolecules while also serving as signaling platforms for the cell. Although the functions executed by mitochondria are complex, at its core these roles are, to a certain degree, fulfilled by electron transfer reactions and the establishment of a protonmotive force (PMF). Indeed, mitochondria are energy conserving organelles that extract electrons from nutrients to establish a PMF, which is then used to drive ATP and NADPH production, solute import, and many other functions including the propagation of cell signals. These same electrons extracted from nutrients are also used to produce ROS, pro-oxidants that can have potentially damaging effects at high levels, but also serve as secondary messengers at low amounts. Mitochondria are also enriched with antioxidant defenses, which are required to buffer cellular ROS. These same redox buffering networks also fulfill another important role; regulation of proteins through the reversible oxidation of cysteine switches. The modification of cysteine switches with the antioxidant glutathione, a process called protein S-glutathionylation, has been found to play an integral role in controlling various mitochondrial functions. In addition, recent findings have demonstrated that disrupting mitochondrial protein S-glutathionylation reactions can have some dire pathological consequences. Accordingly, this chapter focuses on the role of mitochondrial cysteine switches in the modulation of different physiological functions and how defects in these pathways contribute to the development of disease.
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Affiliation(s)
- Ryan J Mailloux
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, Canada.
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11
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Young A, Gill R, Mailloux RJ. Protein S-glutathionylation: The linchpin for the transmission of regulatory information on redox buffering capacity in mitochondria. Chem Biol Interact 2018; 299:151-162. [PMID: 30537466 DOI: 10.1016/j.cbi.2018.12.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 11/08/2018] [Accepted: 12/07/2018] [Indexed: 01/01/2023]
Abstract
Protein S-glutathionylation reactions are a ubiquitous oxidative modification required to control protein function in response to changes in redox buffering capacity. These reactions are rapid and reversible and are, for the most part, enzymatically mediated by glutaredoxins (GRX) and glutathione S-transferases (GST). Protein S-glutathionylation has been found to control a range of cell functions in response to different physiological cues. Although these reactions occur throughout the cell, mitochondrial proteins seem to be highly susceptible to reversible S-glutathionylation, a feature attributed to the unique physical properties of this organelle. Indeed, mitochondria contain a number of S-glutathionylation targets which includes proteins involved in energy metabolism, solute transport, reactive oxygen species (ROS) production, proton leaks, apoptosis, antioxidant defense, and mitochondrial fission and fusion. Moreover, it has been found that conjugation and removal of glutathione from proteins in mitochondria fulfills a number of important physiological roles and defects in these reactions can have some dire pathological consequences. Here, we provide an updated overview on mitochondrial protein S-glutathionylation reactions and their importance in cell functions and physiology.
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Affiliation(s)
- Adrian Young
- Department of Biochemistry, Faculty of Science, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Robert Gill
- Department of Biochemistry, Faculty of Science, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Ryan J Mailloux
- Department of Biochemistry, Faculty of Science, Memorial University of Newfoundland, St. John's, NL, Canada.
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12
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Ježek P, Holendová B, Garlid KD, Jabůrek M. Mitochondrial Uncoupling Proteins: Subtle Regulators of Cellular Redox Signaling. Antioxid Redox Signal 2018; 29:667-714. [PMID: 29351723 PMCID: PMC6071544 DOI: 10.1089/ars.2017.7225] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
SIGNIFICANCE Mitochondria are the energetic, metabolic, redox, and information signaling centers of the cell. Substrate pressure, mitochondrial network dynamics, and cristae morphology state are integrated by the protonmotive force Δp or its potential component, ΔΨ, which are attenuated by proton backflux into the matrix, termed uncoupling. The mitochondrial uncoupling proteins (UCP1-5) play an eminent role in the regulation of each of the mentioned aspects, being involved in numerous physiological events including redox signaling. Recent Advances: UCP2 structure, including purine nucleotide and fatty acid (FA) binding sites, strongly support the FA cycling mechanism: UCP2 expels FA anions, whereas uncoupling is achieved by the membrane backflux of protonated FA. Nascent FAs, cleaved by phospholipases, are preferential. The resulting Δp dissipation decreases superoxide formation dependent on Δp. UCP-mediated antioxidant protection and its impairment are expected to play a major role in cell physiology and pathology. Moreover, UCP2-mediated aspartate, oxaloacetate, and malate antiport with phosphate is expected to alter metabolism of cancer cells. CRITICAL ISSUES A wide range of UCP antioxidant effects and participations in redox signaling have been reported; however, mechanisms of UCP activation are still debated. Switching off/on the UCP2 protonophoretic function might serve as redox signaling either by employing/releasing the extra capacity of cell antioxidant systems or by directly increasing/decreasing mitochondrial superoxide sources. Rapid UCP2 degradation, FA levels, elevation of purine nucleotides, decreased Mg2+, or increased pyruvate accumulation may initiate UCP-mediated redox signaling. FUTURE DIRECTIONS Issues such as UCP2 participation in glucose sensing, neuronal (synaptic) function, and immune cell activation should be elucidated. Antioxid. Redox Signal. 29, 667-714.
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Affiliation(s)
- Petr Ježek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Blanka Holendová
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
| | - Keith D Garlid
- 2 UCLA Cardiovascular Research Laboratory, David Geffen School of Medicine at UCLA , Los Angeles, California
| | - Martin Jabůrek
- 1 Department of Mitochondrial Physiology, Institute of Physiology of the Czech Academy of Sciences , Prague, Czech Republic
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Gill RM, O’Brien M, Young A, Gardiner D, Mailloux RJ. Protein S-glutathionylation lowers superoxide/hydrogen peroxide release from skeletal muscle mitochondria through modification of complex I and inhibition of pyruvate uptake. PLoS One 2018; 13:e0192801. [PMID: 29444156 PMCID: PMC5812644 DOI: 10.1371/journal.pone.0192801] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 01/30/2018] [Indexed: 01/23/2023] Open
Abstract
Protein S-glutathionylation is a reversible redox modification that regulates mitochondrial metabolism and reactive oxygen species (ROS) production in liver and cardiac tissue. However, whether or not it controls ROS release from skeletal muscle mitochondria has not been explored. In the present study, we examined if chemically-induced protein S-glutathionylation could alter superoxide (O2●-)/hydrogen peroxide (H2O2) release from isolated muscle mitochondria. Disulfiram, a powerful chemical S-glutathionylation catalyst, was used to S-glutathionylate mitochondrial proteins and ascertain if it can alter ROS production. It was found that O2●-/H2O2 release rates from permeabilized muscle mitochondria decreased with increasing doses of disulfiram (100–500 μM). This effect was highest in mitochondria oxidizing succinate or palmitoyl-carnitine, where a ~80–90% decrease in the rate of ROS release was observed. Similar effects were detected in intact mitochondria respiring under state 4 conditions. Incubation of disulfiram-treated mitochondria with DTT (2 mM) restored ROS release confirming that these effects were associated with protein S-glutathionylation. Disulfiram treatment also inhibited phosphorylating and proton leak-dependent respiration. Radiolabelled substrate uptake experiments demonstrated that disulfiram inhibited pyruvate import but had no effect on carnitine uptake. Immunoblot analysis of complex I revealed that it contained several protein S-glutathionylation targets including NDUSF1, a subunit required for NADH oxidation. Taken together, these results demonstrate that O2●-/H2O2 release from muscle mitochondria can be altered by protein S-glutathionylation. We attribute these changes to the protein S-glutathionylation complex I and inhibition of mitochondrial pyruvate carrier.
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Affiliation(s)
- Robert M. Gill
- Memorial University of Newfoundland, Department of Biochemistry, St. John’s, Newfoundland, Canada
| | - Marisa O’Brien
- Memorial University of Newfoundland, Department of Biochemistry, St. John’s, Newfoundland, Canada
| | - Adrian Young
- Memorial University of Newfoundland, Department of Biochemistry, St. John’s, Newfoundland, Canada
| | - Danielle Gardiner
- Memorial University of Newfoundland, Department of Biochemistry, St. John’s, Newfoundland, Canada
| | - Ryan J. Mailloux
- Memorial University of Newfoundland, Department of Biochemistry, St. John’s, Newfoundland, Canada
- * E-mail:
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14
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Alcock LJ, Perkins MV, Chalker JM. Chemical methods for mapping cysteine oxidation. Chem Soc Rev 2018; 47:231-268. [DOI: 10.1039/c7cs00607a] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Methods to characterise oxidative modifications of cysteine help clarify their role in protein function in both healthy and diseased cells.
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Affiliation(s)
- Lisa J. Alcock
- College of Science and Engineering
- Flinders University
- South Australia
- Australia
| | - Michael V. Perkins
- College of Science and Engineering
- Flinders University
- South Australia
- Australia
| | - Justin M. Chalker
- College of Science and Engineering
- Flinders University
- South Australia
- Australia
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15
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Mitochondrial stress controls the radiosensitivity of the oxygen effect: Implications for radiotherapy. Oncotarget 2017; 7:21469-83. [PMID: 26894978 PMCID: PMC5008299 DOI: 10.18632/oncotarget.7412] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 01/29/2016] [Indexed: 01/05/2023] Open
Abstract
It has been more than 60 years since the discovery of the oxygen effect that empirically demonstrates the direct association between cell radiosensitivity and oxygen tension, important parameters in radiotherapy. Yet the mechanisms underlying this principal tenet of radiobiology are poorly understood. Better understanding of the oxygen effect may explain difficulty in eliminating hypoxic tumor cells, a major cause of regrowth after therapy. Our analysis utilizes the Howard-Flanders and Alper formula, which describes the relationship of radiosensitivity with oxygen tension. Here, we assign and qualitatively assess the relative contributions of two important mechanisms. The first mechanism involves the emission of reactive oxygen species from the mitochondrial electron transport chain, which increases with oxygen tension. The second mechanism is related to an energy and repair deficit, which increases with hypoxia. Following a radiation exposure, the uncoupling of the oxidative phosphorylation system (proton leak) in mitochondria lowers the emission of reactive oxygen species which has implications for fractionated radiotherapy, particularly of hypoxic tumors. Our analysis shows that, in oxygenated tumor and normal cells, mitochondria, rather than the nucleus, are the primary loci of radiotherapy effects, especially for low linear energy transfer radiation. Therefore, the oxygen effect can be explained by radiation-induced effects in mitochondria that generate reactive oxygen species, which in turn indirectly target nuclear DNA.
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Bouvy C, Wannez A, Laloy J, Chatelain C, Dogné JM. Transfer of multidrug resistance among acute myeloid leukemia cells via extracellular vesicles and their microRNA cargo. Leuk Res 2017; 62:70-76. [DOI: 10.1016/j.leukres.2017.09.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 07/31/2017] [Accepted: 09/24/2017] [Indexed: 12/29/2022]
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17
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Mitochondrial uncoupling in cancer cells: Liabilities and opportunities. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:655-664. [DOI: 10.1016/j.bbabio.2017.01.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 12/16/2016] [Accepted: 01/05/2017] [Indexed: 12/12/2022]
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FABP4/aP2 Regulates Macrophage Redox Signaling and Inflammasome Activation via Control of UCP2. Mol Cell Biol 2017; 37:MCB.00282-16. [PMID: 27795298 DOI: 10.1128/mcb.00282-16] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 10/14/2016] [Indexed: 12/19/2022] Open
Abstract
Obesity-linked metabolic disease is mechanistically associated with the accumulation of proinflammatory macrophages in adipose tissue, leading to increased reactive oxygen species (ROS) production and chronic low-grade inflammation. Previous work has demonstrated that deletion of the adipocyte fatty acid-binding protein (FABP4/aP2) uncouples obesity from inflammation via upregulation of the uncoupling protein 2 (UCP2). Here, we demonstrate that ablation of FABP4/aP2 regulates systemic redox capacity and reduces cellular protein sulfhydryl oxidation and, in particular, oxidation of mitochondrial protein cysteine residues. Coincident with the loss of FABP4/aP2 is the upregulation of the antioxidants superoxide dismutase (SOD2), catalase, methionine sulfoxide reductase A, and the 20S proteasome subunits PSMB5 and αβ. Reduced mitochondrial protein oxidation in FABP4/aP2-/- macrophages attenuates the mitochondrial unfolded-protein response (mtUPR) as measured by expression of heat shock protein 60, Clp protease, and Lon peptidase 1. Consistent with a diminished mtUPR, FABP4/aP2-/- macrophages exhibit reduced expression of cleaved caspase-1 and NLRP3. Secretion of interleukin 1β (IL-1β), in response to inflammasome activation, is ablated in FABP4/aP2-/- macrophages, as well as in FABP4/aP2 inhibitor-treated cells, but partially rescued in FABP4/aP2-null macrophages when UCP2 is silenced. Collectively, these data offer a novel pathway whereby FABP4/aP2 regulates macrophage redox signaling and inflammasome activation via control of UCP2 expression.
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Brandi J, Cecconi D, Cordani M, Torrens-Mas M, Pacchiana R, Dalla Pozza E, Butera G, Manfredi M, Marengo E, Oliver J, Roca P, Dando I, Donadelli M. The antioxidant uncoupling protein 2 stimulates hnRNPA2/B1, GLUT1 and PKM2 expression and sensitizes pancreas cancer cells to glycolysis inhibition. Free Radic Biol Med 2016; 101:305-316. [PMID: 27989750 DOI: 10.1016/j.freeradbiomed.2016.10.499] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 10/12/2016] [Accepted: 10/24/2016] [Indexed: 01/09/2023]
Abstract
Several evidence indicate that metabolic alterations play a pivotal role in cancer development. Here, we report that the mitochondrial uncoupling protein 2 (UCP2) sustains the metabolic shift from mitochondrial oxidative phosphorylation (mtOXPHOS) to glycolysis in pancreas cancer cells. Indeed, we show that UCP2 sensitizes pancreas cancer cells to the treatment with the glycolytic inhibitor 2-deoxy-D-glucose. Through a bidimensional electrophoresis analysis, we identify 19 protein species differentially expressed after treatment with the UCP2 inhibitor genipin and, by bioinformatic analyses, we show that these proteins are mainly involved in metabolic processes. In particular, we demonstrate that the antioxidant UCP2 induces the expression of hnRNPA2/B1, which is involved in the regulation of both GLUT1 and PKM2 mRNAs, and of lactate dehydrogenase (LDH) increasing the secretion of L-lactic acid. We further demonstrate that the radical scavenger N-acetyl-L-cysteine reverts hnRNPA2/B1 and PKM2 inhibition by genipin indicating a role for reactive oxygen species in the metabolic reprogramming of cancer cells mediated by UCP2. We also observe an UCP2-dependent decrease in mtOXPHOS complex I (NADH dehydrogenase), complex IV (cytochrome c oxidase), complex V (ATPase) and in mitochondrial oxygen consumption, suggesting a role for UCP2 in the counteraction of pancreatic cancer cellular respiration. All these results reveal novel mechanisms through which UCP2 promotes cancer cell proliferation with the concomitant metabolic shift from mtOXPHOS to the glycolytic pathway.
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Affiliation(s)
- Jessica Brandi
- Department of Biotechnology, Proteomics and Mass Spectrometry Laboratory, University of Verona, Verona, Italy
| | - Daniela Cecconi
- Department of Biotechnology, Proteomics and Mass Spectrometry Laboratory, University of Verona, Verona, Italy
| | - Marco Cordani
- Department of Neuroscience, Biomedicine and Movement, Biochemistry Section, University of Verona, Verona, Italy
| | - Margalida Torrens-Mas
- Physiopathology of Obesity and Nutrition, CIBERobn (CB06/03), Carlos III Health Research Institute (ISCIII), Madrid, Spain; Palma Institute for Health Research (IdISPa), E07010 Palma, Spain; Multidisciplinar Group of Translational Oncology, University Research Institute on Health Sciences (IUNICS), University of the Balearic Islands, E07122 Palma, Spain
| | - Raffaella Pacchiana
- Department of Neuroscience, Biomedicine and Movement, Biochemistry Section, University of Verona, Verona, Italy
| | - Elisa Dalla Pozza
- Department of Neuroscience, Biomedicine and Movement, Biochemistry Section, University of Verona, Verona, Italy
| | - Giovanna Butera
- Department of Neuroscience, Biomedicine and Movement, Biochemistry Section, University of Verona, Verona, Italy
| | - Marcello Manfredi
- Department of Sciences and Technological Innovation, University of Eastern Piedmont, Alessandria, Italy; ISALIT, Novara, Italy
| | - Emilio Marengo
- Department of Sciences and Technological Innovation, University of Eastern Piedmont, Alessandria, Italy
| | - Jordi Oliver
- Physiopathology of Obesity and Nutrition, CIBERobn (CB06/03), Carlos III Health Research Institute (ISCIII), Madrid, Spain; Palma Institute for Health Research (IdISPa), E07010 Palma, Spain; Multidisciplinar Group of Translational Oncology, University Research Institute on Health Sciences (IUNICS), University of the Balearic Islands, E07122 Palma, Spain
| | - Pilar Roca
- Physiopathology of Obesity and Nutrition, CIBERobn (CB06/03), Carlos III Health Research Institute (ISCIII), Madrid, Spain; Palma Institute for Health Research (IdISPa), E07010 Palma, Spain; Multidisciplinar Group of Translational Oncology, University Research Institute on Health Sciences (IUNICS), University of the Balearic Islands, E07122 Palma, Spain
| | - Ilaria Dando
- Department of Neuroscience, Biomedicine and Movement, Biochemistry Section, University of Verona, Verona, Italy.
| | - Massimo Donadelli
- Department of Neuroscience, Biomedicine and Movement, Biochemistry Section, University of Verona, Verona, Italy.
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20
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Dynamic regulation of uncoupling protein 2 expression by microRNA-214 in hepatocellular carcinoma. Biosci Rep 2016; 36:BSR20160062. [PMID: 27129291 PMCID: PMC5293557 DOI: 10.1042/bsr20160062] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 04/07/2016] [Indexed: 12/31/2022] Open
Abstract
Gemcitabine (GEM), a commonly used chemotherapeutic agent in hepatocellular carcinoma (HCC) patients, uses oxidative stress induction as a common effector pathway. However, GEM alone or in combination with oxaliplatin hardly renders any survival benefits to HCC patients. We have recently shown that this is part due to the overexpression of the mitochondrial uncoupling protein 2 (UCP2) that in turn mediates resistance to GEM in HCC patients. However, not much is known about regulatory mechanisms underlying UCP2 overexpression in HCC. Differential protein expression in HCC cell lines did not show a concomitant change in UCP2 transcript level, indicating post-transcriptional or post-translational regulatory mechanism. In situ analysis revealed that UCP2 is a putative target of miR-214 miR-214 expression is significantly down-regulated in HCC patient samples as compared with normal adjacent tissues and in cell line, human hepatoblastoma cells (HuH6), with high UCP2 protein expression. We demonstrated using miR-214 mimic and antagomir that the miRNA targeted UCP2 expression by directly targeting the wild-type, but not a miR-214 seed mutant, 3' UTR of UCP2 Overexpression of miR-214 significantly attenuated cell proliferation. Finally, analysis in 20 HCC patients revealed an inverse correlation in expression of UCP2 and miR-214 (Pearson's correlation coefficient, r=-0.9792). Cumulatively, our data indicate that in the context of HCC, miR-214 acts as a putative tumour suppressor by targeting UCP2 and defines a novel mechanism of regulation of UCP2.
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21
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Wang R, MoYung KC, Zhang MH, Poon K. UCP2- and non-UCP2-mediated electric current in eukaryotic cells exhibits different properties. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:19618-19631. [PMID: 26276275 DOI: 10.1007/s11356-015-5155-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 08/04/2015] [Indexed: 06/04/2023]
Abstract
Using live eukaryotic cells, including cancer cells, MCF-7 and HCT-116, normal hepatocytes and red blood cells in anode and potassium ferricyanide in cathode of MFC could generate bio-based electric current. Electrons and protons generated from the metabolic reaction in both cytosol and mitochondria contributing to the leaking would mediate the generation of electric current. Both resveratrol (RVT) and 2,4-dinitrophenol (DNP) used to induce proton leak in mitochondria were found to promote electric current production in all cells except red blood cells without mitochondria. Proton leak might be important for electric current production by bringing the charge balance in cells to enhance the further electron leak. The induced electric current by RVT can be blocked by Genipin, an inhibitor of UCP2-mediated proton leak, while that induced by DNP cannot. RVT could reduce reactive oxygen species (ROS) level in cells better than that of DNP. In addition, RVT increased mitochondrial membrane potential (MMP), while DNP decreased it. Results highly suggested the existence of at least two types of electric current that showed different properties. They included UCP2-mediated and non-UCP2-mediated electric current. UCP2-mediated electric current exhibited higher reactive oxygen species (ROS) reduction effect per unit electric current production than that of non-UCP2-mediated electric current. Higher UCP2-mediated electric current observed in cancer cells might contribute to the mechanism of drug resistence. Correlation could not be established between electric current production with either ROS and MMP without distinguishing the types of electric current.
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Affiliation(s)
- Ruihua Wang
- Department of Gastroenterology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital South Campus, 6600 Nanfeng Road, Fengxian District, Shanghai, China, 201499.
| | - K C MoYung
- Program of Food Science and Technology, Division of Science and Technology, BNU-HKBU United International College, 28 Jinfeng Road, Tangjiawan, Zhuhai, Guangdong, China, 519085.
| | - M H Zhang
- Program of Food Science and Technology, Division of Science and Technology, BNU-HKBU United International College, 28 Jinfeng Road, Tangjiawan, Zhuhai, Guangdong, China, 519085
| | - Karen Poon
- Program of Food Science and Technology, Division of Science and Technology, BNU-HKBU United International College, 28 Jinfeng Road, Tangjiawan, Zhuhai, Guangdong, China, 519085.
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MiR-133a Is Functionally Involved in Doxorubicin-Resistance in Breast Cancer Cells MCF-7 via Its Regulation of the Expression of Uncoupling Protein 2. PLoS One 2015; 10:e0129843. [PMID: 26107945 PMCID: PMC4481265 DOI: 10.1371/journal.pone.0129843] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 05/13/2015] [Indexed: 12/13/2022] Open
Abstract
The development of novel targeted therapies holds promise for conquering chemotherapy resistance, which is one of the major hurdles in current breast cancer treatment. Previous studies indicate that mitochondria uncoupling protein 2 (UCP-2) is involved in the development of chemotherapy resistance in colon cancer and lung cancer cells. In the present study we found that lower level of miR133a is accompanied by increased expression of UCP-2 in Doxorubicin-resistant breast cancer cell cline MCF-7/Dox as compared with its parental cell line MCF-7. We postulated that miR133a might play a functional role in the development of Doxorubicin-resistant in breast cancer cells. In this study we showed that: 1) exogenous expression of miR133a in MCF-7/Dox cells can sensitize their reaction to the treatment of Doxorubicin, which is coincided with reduced expression of UCP-2; 2) knockdown of UCP-2 in MCF-7/Dox cells can also sensitize their reaction to the treatment of Doxorubicin; 3) intratumoral delivering of miR133a can restore Doxorubicin treatment response in Doxorubicin-resistant xenografts in vivo, which is concomitant with the decreased expression of UCP-2. These findings provided direct evidences that the miR133a/UCP-2 axis might play an essential role in the development of Doxorubicin-resistance in breast cancer cells, suggesting that the miR133a/UCP-2 signaling cohort could be served as a novel therapeutic target for the treatment of chemotherapy resistant in breast cancer.
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Uncoupling protein 2 mediates resistance to gemcitabine-induced apoptosis in hepatocellular carcinoma cell lines. Biosci Rep 2015; 35:BSR20150116. [PMID: 26181366 PMCID: PMC4613703 DOI: 10.1042/bsr20150116] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 06/03/2015] [Indexed: 12/24/2022] Open
Abstract
Our results suggest a critical role for mitochondrial uncoupling in gemcitabine (GEM) resistance in hepatocellular carcinoma (HCC) cell lines. Hence, synergistic targeting of uncoupling protein 2 (UCP2) in combination with other chemotherapeutic agents might be more potent in HCC patients. Oxidative stress induction is a common effector pathway for commonly used chemotherapeutic agents like gemcitabine (GEM) in hepatocellular carcinoma (HCC) patients. However, GEM alone or in combination with oxiplatin hardly renders any survival benefits to HCC patients. Mitochondrial uncoupling protein 2 (UCP2) is known to suppress mitochondrial reactive oxygen species (ROS) generation, thus mitigating oxidative stress-induced apoptosis. We demonstrate in the present study, using a panel of HCC cell lines that sensitivity to GEM in HCC well correlate with the endogenous level of UCP2 protein expression. Moreover, ectopic overexpression of UCP2 in a HCC cell line with low endogenous UCP2 expression, HLE, significantly decreased mitochondrial superoxide induction by the anti-cancer drug GEM. Conversely, UCP2 mRNA silencing by RNA interference in HCC cell lines with high endogenous UCP2 expression significantly enhanced GEM-induced mitochondrial superoxide generation and apoptosis. Cumulatively, our results suggest a critical role for mitochondrial uncoupling in GEM resistance in HCC cell lines. Hence, synergistic targeting of UCP2 in combination with other chemotherapeutic agents might be more potent in HCC patients.
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24
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Qiao C, Wei L, Dai Q, Zhou Y, Yin Q, Li Z, Xiao Y, Guo Q, Lu N. UCP2-related mitochondrial pathway participates in oroxylin A-induced apoptosis in human colon cancer cells. J Cell Physiol 2015; 230:1054-63. [PMID: 25251374 DOI: 10.1002/jcp.24833] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 08/24/2014] [Accepted: 09/18/2014] [Indexed: 12/21/2022]
Abstract
Oroxylin A is a flavonoid extracted from the root of Scutellaria baicalensis Georgi. Our previous research demonstrated that oroxylin A have various anti-tumor effects including apoptosis, cell cycle arrest, drug-resistant reversion, and others. This paper explores the mechanism how oroxylin A induce apoptosis by regulating uncoupling protein 2 (UCP2) in human colon cancer cells. We found that the inhibition of UCP2 by UCP2 siRNA significantly increased the sensitivity of cells to drugs, reactive oxygen species (ROS) generation and the opening of mitochondrial permeability transition pore (MPTP) of CaCo-2 cells. We also found that UCP2 inhibition could lead to ROS-mediated MPTP activation. Furthermore, we demonstrated that oroxylin A triggered MPTP-dependent pro-apoptotic protein release from mitochondria to matrix and then induced apoptotic cascade by inhibiting UCP2. Intriguingly, the inhibition of UCP2 by oroxylin A was able to block Bcl-2 translocation to the mitochondria, keeping MPTP at open-state. In conclusion, we have demonstrated that UCP2 plays a key role in mitochondrial apoptotic pathway; UCP2s inhibition by oroxylin A triggers the MPTP opening, and promotes the apoptosis in CaCo-2 cells.
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Affiliation(s)
- Chen Qiao
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, Tongjiaxiang, Nanjing, People's Republic of China
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25
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Truong J, Mailloux RJ, Chan HM. Impact of methylmercury exposure on mitochondrial energetics in AC16 and H9C2 cardiomyocytes. Toxicol In Vitro 2015; 29:953-61. [PMID: 25835517 DOI: 10.1016/j.tiv.2015.03.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 10/23/2022]
Abstract
It has been reported that chronic low dose exposures of methylmercury (MeHg) is associated with cardiovascular diseases in many populations worldwide. The toxic mechanisms through which these adverse effects occur are currently unknown. The objective of this study was to determine the bioenergetic and cytotoxic effects of MeHg on AC16 and H9C2 cardiomyocyte cell lines. Both cell lines exhibit significantly decreased mitochondrial function, cell viability and increased reactive oxygen species (ROS) production. Decreases in maximal respiration and reserve capacity was observed in both cell lines at 1μM. Bioenergetic profile experiments were also performed in tandem with cells exposed to diamide or menadione, compounds which accumulate in mitochondria and disrupt oxidative phosphorylation. AC16 cells show MeHg dose dependant sensitivities with Stateapparent and ATP production values, but H9C2 cells do not show these trends. H9C2 cells may be more resistant to MeHg toxicity than AC16 cells as reflected in the increases of proton leak and Stateapparent. No changes in expression of respiratory complexes were observed. Results suggest that MeHg has the potential to induce cytotoxicity. Furthermore, MeHg may have differential effects on AC16 and H9C2 cells, derived from human and rat cardiac tissue respectively, suggesting that differences in MeHg toxicity may be species-dependent.
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Affiliation(s)
- Jocelyn Truong
- Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Ryan J Mailloux
- Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Hing Man Chan
- Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
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26
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Thrush AB, Zhang R, Chen W, Seifert EL, Quizi JK, McPherson R, Dent R, Harper ME. Lower mitochondrial proton leak and decreased glutathione redox in primary muscle cells of obese diet-resistant versus diet-sensitive humans. J Clin Endocrinol Metab 2014; 99:4223-30. [PMID: 25148230 DOI: 10.1210/jc.2014-1726] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
CONTEXT Weight loss success in response to energy restriction is highly variable. This may be due in part to differences in mitochondrial function and oxidative stress. OBJECTIVE The objective of the study was to determine whether mitochondrial function, content, and oxidative stress differ in well-matched obese individuals in the upper [obese diet sensitive (ODS)] vs lower quintiles [obese diet resistant (ODR)] for rate of weight loss. DESIGN Primary myotubes derived from muscle biopsies of individuals identified as ODS or ODR were studied. SETTING Compliant ODS and ODR females who completed in the Ottawa Hospital Weight Management Program and identified as ODS and ODR participated in this study. PATIENTS OR OTHER PARTICIPANTS Eleven ODS and nine ODR weight-stable females matched for age, body mass, and body mass index participated in this study. INTERVENTION Vastus lateralis muscle biopsies were obtained and processed for muscle satellite cell isolation. MAIN OUTCOME MEASURES Mitochondrial respiration, content, reactive oxygen species, and glutathione redox ratios were measured in the myotubes of ODS and ODR individuals. RESULTS Mitochondrial proton leak was increased in myotubes of ODS compared with ODR (P < .05). Reduced and oxidized glutathione was decreased in the myotubes of ODR vs ODS (P < .05), indicating a more oxidized glutathione redox state. There were no differences in myotube mitochondrial content, uncoupling protein 3, or adenine nucleotide translocase levels. CONCLUSIONS Lower rate of mitochondrial proton leak in muscle is a cell autonomous phenomenon in ODR vs ODS individuals, and this is associated with a more oxidized glutathione redox state in ODR vs ODS myotubes. The muscle of ODR subjects may thus have a lower capacity to adapt to oxidative stress as compared with ODS.
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Affiliation(s)
- A Brianne Thrush
- Department of Biochemistry, Microbiology, and Immunology (A.B.T., R.Z., W.C., E.L.S., J.K.Q., M.-E.H.), Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5; Department of Pathology, Anatomy, and Cell Biology (E.L.S.), Thomas Jefferson University, Philadelphia, Pennsylvania 19107; Division of Cardiology (R.M.), University of Ottawa Heart Institute, Ottawa, Ontario Canada K1Y 4W7; Ottawa Hospital Weight Management Clinic (R.D.), Ottawa Hospital, Ottawa, Ontario, Canada K1Y 4E9
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27
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Donadelli M, Dando I, Fiorini C, Palmieri M. UCP2, a mitochondrial protein regulated at multiple levels. Cell Mol Life Sci 2014; 71:1171-90. [PMID: 23807210 PMCID: PMC11114077 DOI: 10.1007/s00018-013-1407-0] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 05/16/2013] [Accepted: 06/10/2013] [Indexed: 12/11/2022]
Abstract
An ever-increasing number of studies highlight the role of uncoupling protein 2 (UCP2) in a broad range of physiological and pathological processes. The knowledge of the molecular mechanisms of UCP2 regulation is becoming fundamental in both the comprehension of UCP2-related physiological events and the identification of novel therapeutic strategies based on UCP2 modulation. The study of UCP2 regulation is a fast-moving field. Recently, several research groups have made a great effort to thoroughly understand the various molecular mechanisms at the basis of UCP2 regulation. In this review, we describe novel findings concerning events that can occur in a concerted manner at various levels: Ucp2 gene mutation (single nucleotide polymorphisms), UCP2 mRNA and protein expression (transcriptional, translational, and protein turn-over regulation), UCP2 proton conductance (ligands and post-transcriptional modifications), and nutritional and pharmacological regulation of UCP2.
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Affiliation(s)
- Massimo Donadelli
- Section of Biochemistry, Deparment of Life and Reproduction Sciences, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy,
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28
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JEŽEK P, OLEJÁR T, SMOLKOVÁ K, JEŽEK J, DLASKOVÁ A, PLECITÁ-HLAVATÁ L, ZELENKA J, ŠPAČEK T, ENGSTOVÁ H, PAJUELO REGUERA D, JABŮREK M. Antioxidant and Regulatory Role of Mitochondrial Uncoupling Protein UCP2 in Pancreatic β-cells. Physiol Res 2014; 63:S73-91. [DOI: 10.33549/physiolres.932633] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Research on brown adipose tissue and its hallmark protein, mitochondrial uncoupling protein UCP1, has been conducted for half a century and has been traditionally studied in the Institute of Physiology (AS CR, Prague), likewise UCP2 residing in multiple tissues for the last two decades. Our group has significantly contributed to the elucidation of UCP uncoupling mechanism, fully dependent on free fatty acids (FFAs) within the inner mitochondrial membrane. Now we review UCP2 physiological roles emphasizing its roles in pancreatic β-cells, such as antioxidant role, possible tuning of redox homeostasis (consequently UCP2 participation in redox regulations), and fine regulation of glucose-stimulated insulin secretion (GSIS). For example, NADPH has been firmly established as being a modulator of GSIS and since UCP2 may influence redox homeostasis, it likely affects NADPH levels. We also point out the role of phospholipase iPLA2 isoform in providing FFAs for the UCP2 antioxidant function. Such initiation of mild uncoupling hypothetically precedes lipotoxicity in pancreatic β-cells until it reaches the pathological threshold, after which the antioxidant role of UCP2 can be no more cell-protective, for example due to oxidative stress-accumulated mutations in mtDNA. These mechanisms, together with impaired autocrine insulin function belong to important causes of Type 2 diabetes etiology.
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Affiliation(s)
- P. JEŽEK
- Department of Membrane Transport Biophysics, Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic
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29
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Mailloux RJ, Jin X, Willmore WG. Redox regulation of mitochondrial function with emphasis on cysteine oxidation reactions. Redox Biol 2013; 2:123-39. [PMID: 24455476 PMCID: PMC3895620 DOI: 10.1016/j.redox.2013.12.011] [Citation(s) in RCA: 210] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 12/13/2013] [Indexed: 12/13/2022] Open
Abstract
Mitochondria have a myriad of essential functions including metabolism and apoptosis. These chief functions are reliant on electron transfer reactions and the production of ATP and reactive oxygen species (ROS). The production of ATP and ROS are intimately linked to the electron transport chain (ETC). Electrons from nutrients are passed through the ETC via a series of acceptor and donor molecules to the terminal electron acceptor molecular oxygen (O2) which ultimately drives the synthesis of ATP. Electron transfer through the respiratory chain and nutrient oxidation also produces ROS. At high enough concentrations ROS can activate mitochondrial apoptotic machinery which ultimately leads to cell death. However, if maintained at low enough concentrations ROS can serve as important signaling molecules. Various regulatory mechanisms converge upon mitochondria to modulate ATP synthesis and ROS production. Given that mitochondrial function depends on redox reactions, it is important to consider how redox signals modulate mitochondrial processes. Here, we provide the first comprehensive review on how redox signals mediated through cysteine oxidation, namely S-oxidation (sulfenylation, sulfinylation), S-glutathionylation, and S-nitrosylation, regulate key mitochondrial functions including nutrient oxidation, oxidative phosphorylation, ROS production, mitochondrial permeability transition (MPT), apoptosis, and mitochondrial fission and fusion. We also consider the chemistry behind these reactions and how they are modulated in mitochondria. In addition, we also discuss emerging knowledge on disorders and disease states that are associated with deregulated redox signaling in mitochondria and how mitochondria-targeted medicines can be utilized to restore mitochondrial redox signaling.
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Affiliation(s)
- Ryan J. Mailloux
- Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6
- Toxicology Research Division, Food Directorate, HPFB, Health Canada, Ottawa, Ontario, Canada K1A 0K9
| | - Xiaolei Jin
- Toxicology Research Division, Food Directorate, HPFB, Health Canada, Ottawa, Ontario, Canada K1A 0K9
| | - William G. Willmore
- Institute of Biochemistry, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6
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30
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Mailloux RJ, McBride SL, Harper ME. Unearthing the secrets of mitochondrial ROS and glutathione in bioenergetics. Trends Biochem Sci 2013; 38:592-602. [PMID: 24120033 DOI: 10.1016/j.tibs.2013.09.001] [Citation(s) in RCA: 203] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/04/2013] [Accepted: 09/05/2013] [Indexed: 01/06/2023]
Abstract
During the cellular oxidation of fuels, electrons are used to power the proton pumps of the mitochondrial electron transport chain (ETC) and ultimately drive ATP synthesis and the reduction of molecular oxygen to water. During these oxidative processes, some electrons can 'spin off' during fuel oxidation and electron transport to univalently reduce O2, forming reactive oxygen species (ROS). In excess, ROS can be detrimental; however, at low concentrations oxyradicals are essential signaling molecules. Mitochondria thus use a battery of systems to finely control types and levels of ROS, including antioxidants. Several antioxidant systems depend on glutathione. Here, we review mitochondrial ROS homeostatic systems, including emerging knowledge about roles of glutathione in redox balance and the control of protein function by post-translational modification.
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Affiliation(s)
- Ryan J Mailloux
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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31
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Huber SM, Butz L, Stegen B, Klumpp D, Braun N, Ruth P, Eckert F. Ionizing radiation, ion transports, and radioresistance of cancer cells. Front Physiol 2013; 4:212. [PMID: 23966948 PMCID: PMC3743404 DOI: 10.3389/fphys.2013.00212] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 07/24/2013] [Indexed: 12/22/2022] Open
Abstract
The standard treatment of many tumor entities comprises fractionated radiation therapy which applies ionizing radiation to the tumor-bearing target volume. Ionizing radiation causes double-strand breaks in the DNA backbone that result in cell death if the number of DNA double-strand breaks exceeds the DNA repair capacity of the tumor cell. Ionizing radiation reportedly does not only act on the DNA in the nucleus but also on the plasma membrane. In particular, ionizing radiation-induced modifications of ion channels and transporters have been reported. Importantly, these altered transports seem to contribute to the survival of the irradiated tumor cells. The present review article summarizes our current knowledge on the underlying mechanisms and introduces strategies to radiosensitize tumor cells by targeting plasma membrane ion transports.
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Affiliation(s)
- Stephan M Huber
- Department of Radiation Oncology, University of Tübingen Tübingen, Germany
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Aguer C, Pasqua M, Thrush AB, Moffat C, McBurney M, Jardine K, Zhang R, Beauchamp B, Dent R, McPherson R, Harper ME. Increased proton leak and SOD2 expression in myotubes from obese non-diabetic subjects with a family history of type 2 diabetes. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1624-33. [PMID: 23685312 DOI: 10.1016/j.bbadis.2013.05.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 05/06/2013] [Accepted: 05/07/2013] [Indexed: 12/20/2022]
Abstract
Muscle insulin resistance is linked to oxidative stress and decreased mitochondrial function. However, the exact cause of muscle insulin resistance is still unknown. Since offspring of patients with type 2 diabetes mellitus (T2DM) are susceptible to developing insulin resistance, they are ideal for studying the early development of insulin resistance. By using primary muscle cells derived from obese non-diabetic subjects with (FH+) or without (FH-) a family history of T2DM, we aimed to better understand the link between mitochondrial function, oxidative stress, and muscle insulin resistance. Insulin-stimulated glucose uptake and glycogen synthesis were normal in FH+ myotubes. Resting oxygen consumption rate was not different between groups. However, proton leak was higher in FH+ myotubes. This was associated with lower ATP content and decreased mitochondrial membrane potential in FH+ myotubes. Surprisingly, mtDNA content was higher in FH+ myotubes. Oxidative stress level was not different between FH+ and FH- groups. Reactive oxygen species content was lower in FH+ myotubes when differentiated in high glucose/insulin (25mM/150pM), which could be due to higher oxidative stress defenses (SOD2 expression and uncoupled respiration). The increased antioxidant defenses and mtDNA content in FH+ myotubes suggest the existence of compensatory mechanisms, which may provisionally prevent the development of insulin resistance.
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Affiliation(s)
- Céline Aguer
- Department of Biochemistry, University of Ottawa, Ottawa, ON K1H 8M5, Canada
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Mailloux RJ, Xuan JY, Beauchamp B, Jui L, Lou M, Harper ME. Glutaredoxin-2 is required to control proton leak through uncoupling protein-3. J Biol Chem 2013; 288:8365-8379. [PMID: 23335511 DOI: 10.1074/jbc.m112.442905] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Glutathionylation has emerged as a key modification required for controlling protein function in response to changes in cell redox status. Recently, we showed that the glutathionylation state of uncoupling protein-3 (UCP3) modulates the leak of protons back into the mitochondrial matrix, thus controlling reactive oxygen species production. However, whether or not UCP3 glutathionylation is mediated enzymatically has remained unknown because previous work relied on the use of pharmacological agents, such as diamide, to alter the UCP3 glutathionylation state. Here, we demonstrate that glutaredoxin-2 (Grx2), a matrix oxidoreductase, is required to glutathionylate and inhibit UCP3. Analysis of bioenergetics in skeletal muscle mitochondria revealed that knock-out of Grx2 (Grx2(-/-)) increased proton leak in a UCP3-dependent manner. These effects were reversed using diamide, a glutathionylation catalyst. Importantly, the increased leak did not compromise coupled respiration. Knockdown of Grx2 augmented proton leak-dependent respiration in primary myotubes from wild type mice, an effect that was absent in UCP3(-/-) cells. These results confirm that Grx2 deactivates UCP3 by glutathionylation. To our knowledge, this is the first enzyme identified to regulate UCP3 by glutathionylation and is the first study on the role of Grx2 in the regulation of energy metabolism.
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Affiliation(s)
- Ryan J Mailloux
- Department of Biochemistry, Immunology, and Microbiology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Jian Ying Xuan
- Department of Biochemistry, Immunology, and Microbiology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Brittany Beauchamp
- Department of Biochemistry, Immunology, and Microbiology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Linda Jui
- Department of Biochemistry, Immunology, and Microbiology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
| | - Marjorie Lou
- Center of Redox Biology and School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska 68583
| | - Mary-Ellen Harper
- Department of Biochemistry, Immunology, and Microbiology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada.
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