Review
Mitochondrial glutathione: Features, regulation and role in disease

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Abstract

Background

Mitochondria are the powerhouse of mammalian cells and the main source of reactive oxygen species (ROS) associated with oxygen consumption. In addition, they also play a strategic role in controlling the fate of cells through regulation of death pathways. Mitochondrial ROS production fulfills a signaling role through regulation of redox pathways, but also contributes to mitochondrial damage in a number of pathological states.

Scope of review

Mitochondria are exposed to the constant generation of oxidant species, and yet the organelle remains functional due to the existence of an armamentarium of antioxidant defense systems aimed to repair oxidative damage, of which mitochondrial glutathione (mGSH) is of particular relevance. Thus, the aim of the review is to cover the regulation of mGSH and its role in disease.

Major conclusions

Cumulating evidence over recent years has demonstrated the essential role for mGSH in mitochondrial physiology and disease. Despite its high concentration in the mitochondrial matrix, mitochondria lack the enzymes to synthesize GSH de novo, so that mGSH originates from cytosolic GSH via transport through specific mitochondrial carriers, which exhibit sensitivity to membrane dynamics. Depletion of mGSH sensitizes cells to stimuli leading to oxidative stress such as TNF, hypoxia or amyloid β-peptide, thereby contributing to disease pathogenesis.

General significance

Understanding the regulation of mGSH may provide novel insights to disease pathogenesis and toxicity and the opportunity to design therapeutic targets of intervention in cell death susceptibility and disease. This article is part of a Special Issue entitled Cellular functions of glutathione.

Highlights

► Role of mitochondrial GSH in oxidative stress and mitochondrial physiology. ► Description and features of mitochondrial GSH transport carriers. ► Role and mechanisms of mitochondrial GSH in cell death pathways. ► Contribution of mitochondrial GSH in neurodegeneration and liver diseases.

Introduction

Despite its exclusive synthesis in the cytosol, GSH is distributed in intracellular organelles, including endoplasmic reticulum (ER), nucleus and mitochondria. The compartmentalization of GSH in separate redox pools is critical to control compartment-specific needs and functions [1], [2]. In the nucleus, GSH maintains critical protein sulphydryls that are necessary for DNA repair and expression [3] and functions also as a hydrogen donor in ribonucleotide reductase-catalyzed reduction of ribonucleotides to deoxyribonucleotides, thus playing a contributory role in DNA synthesis [4]. Intracellularly GSH is predominantly found in its reduced form except in the ER, where it exists mainly as oxidized glutathione (GSSG), GSSG being the main source of oxidizing equivalents to provide the adequate environment necessary for disulphide bond formation and proper folding of nascent proteins [5]. In mitochondria, however, GSH is mainly found in reduced form and represents a minor fraction of the total GSH pool (10–15%). Considering the volume of the mitochondrial matrix, the concentration of mitochondrial GSH (mGSH) is similar to that of cytosol (10–14 mM) [1], [2], [6], [7].

Mitochondria are an excellent example of subcellular organelles whose function is closely linked to maintenance of redox balance. The mitochondria are the primary intracellular site of oxygen consumption and the major source of reactive oxygen species (ROS), most of them originating from the mitochondrial respiratory chain. Associated with this constant flow of ROS generation mitochondria are a target for the damaging effects of oxygen radicals [8], [9], [10]. Although normal electron transport in mitochondria involves four-electron reduction of molecular oxygen to water, partial reduction reactions occur even under physiological conditions, causing release of superoxide anion (O∙2 ) and hydrogen peroxide. In accordance with this, it has been estimated that the steady-state concentration of O∙2  in the mitochondrial matrix is five- to tenfold higher than in the cytosol [11].

In addition to the ROS generated under physiological settings, toxic or pathological conditions that lead to an impairment of mitochondrial function can increase the release of ROS. Therefore, although mitochondria are exposed to the constant generation of oxidant species, the organelle remains functional due to the existence of an antioxidant defense system, of which mGSH is a critical component, aimed to prevent or repair oxidative damage generated during normal aerobic metabolism. This review summarizes current knowledge on the physiology and function of mGSH and its role in cell death regulation and pathological states.

Section snippets

Mitochondrial oxidative stress and defense

The primary function of mitochondria is to transduce oxygen consumption in the electron transport chain (ETC.) into energy required for myriad cell functions. Although the process is highly efficient, a small fraction of electrons are transferred directly to molecular oxygen, resulting in the generation of O2, which can give rise to other potent ROS as well as reactive nitrogen species (RNS). Therefore, a fine equilibrium between ROS production and removal will determine the physiological vs.

mGSH transport

Despite the high GSH concentration existing in mitochondrial matrix, GSH is not synthesized de novo as mitochondria lack the enzymes required for the synthesis of GSH from its constituent aminoacids. Therefore, mitochondrial GSH arises from the cytosol GSH by the activity of specific carriers [7]. Furthermore, GSH has an overall negative charge at physiological pH and mitochondria exhibit a large negative membrane potential; consequently, although GSH can cross easily the mitochondrial outer

mGSH and cell death

Mitochondria play a central role in various forms of cell death, which are characterized by differential biochemical features, with predominant forms including apoptosis (caspase-dependent and independent), or necrosis. Besides amplifying and mediating extrinsic apoptotic pathways, mitochondria also play a central role in the integration and propagation of death signals originating from inside the cell such as DNA damage, oxidative stress, starvation, as well as those induced by radiation or

mGSH in pathology

Examples for the contribution of mGSH to different diseases have increased over the years. In many pathological settings mGSH depletion is both the consequence of disease progression and the cause of organ failure, and in most cases related to cholesterol-mediated changes in membrane dynamics. Indeed, mitochondrial cholesterol has emerged as an important modulator of MOMP in response to apoptotic stimuli, underlying the importance of this lipid in disease pathogenesis, including alcoholic and

Final remarks

Mitochondria play an essential role in maintaining cells alive by providing the energy needed for multiple signaling cascades and functions. The consumption of molecular oxygen in the respiratory chain is not only the driving force for the ATP synthesis required for cell viability, but also the source of ROS that target mitochondrial and extramitochondrial processes. Mitochondrial GSH plays a critical role to control the damaging effects of mitochondrial generated ROS, and hence its regulation

Acknowledgments

The work was supported by grants: SAF2009-11417, SAF2010-15760, and SAF2011-23031 (Plan Nacional de I + D), Proyectos de Investigación en Salud PI10/02114 and PS09/00056 (Instituto de Salud Carlos III), P50-AA-11999 (Research Center for Liver and Pancreatic Diseases, US National Institute on Alcohol Abuse and Alcoholism) and by CIBEREHD from the Instituto de Salud Carlos III. We want to thank the valuable contributions of Drs. Anna Fernandez, Joan Montero, Francisco Caballero and Gorka Basañez to

References (158)

  • H. Imai et al.

    Biological significance of phospholipid hydroperoxide glutathione peroxidase (PHGPx, GPx4) in mammalian cells

    Free Radic. Biol. Med.

    (2003)
  • K. Yagi et al.

    Expression of human phospholipid hydroperoxide glutathione peroxidase gene for protection of host cells from lipid hydroperoxide-mediated injury

    Biochem. Biophys. Res. Commun.

    (1996)
  • P. Cole-Ezea et al.

    Glutathione peroxidase 4 has a major role in protecting mitochondria from oxidative damage and maintaining oxidative phosphorylation complexes in gut epithelial cells

    Free Radic. Biol. Med.

    (2012)
  • C. Latchoumycandane et al.

    Oxidatively truncated phospholipids are required agents of tumor necrosis factor alpha (TNFalpha)-induced apoptosis

    J. Biol. Chem.

    (2012)
  • F.L. Muller et al.

    Trends in oxidative aging theories

    Free Radic. Biol. Med.

    (2007)
  • S.M. Beer et al.

    Glutaredoxin 2 catalyzes the reversible oxidation and glutathionylation of mitochondrial membrane thiol proteins: implications for mitochondrial redox regulation and antioxidant DEFENSE

    J. Biol. Chem.

    (2004)
  • C.H. Jung et al.

    S-glutathiolated hepatocyte proteins and insulin disulfides as substrates for reduction by glutaredoxin, thioredoxin, protein disulfide isomerase, and glutathione

    Arch. Biochem. Biophys.

    (1996)
  • M. Lundberg et al.

    Cloning and expression of a novel human glutaredoxin (Grx2) with mitochondrial and nuclear isoforms

    J. Biol. Chem.

    (2001)
  • V.N. Gladyshev et al.

    Identification and characterization of a new mammalian glutaredoxin (thioltransferase), Grx2

    J. Biol. Chem.

    (2001)
  • C. Johansson et al.

    Human mitochondrial glutaredoxin reduces S-glutathionylated proteins with high affinity accepting electrons from either glutathione or thioredoxin reductase

    J. Biol. Chem.

    (2004)
  • M. Enoksson et al.

    Overexpression of glutaredoxin 2 attenuates apoptosis by preventing cytochrome c release

    Biochem. Biophys. Res. Commun.

    (2005)
  • H.Z. Chae et al.

    Isoforms of mammalian peroxiredoxin that reduce peroxides in presence of thioredoxin

    Methods Enzymol.

    (1999)
  • T.S. Chang et al.

    Peroxiredoxin III, a mitochondrion-specific peroxidase, regulates apoptotic signaling by mitochondria

    J. Biol. Chem.

    (2004)
  • V. Van der Eecken et al.

    Mitochondrial targeting of peroxiredoxin 5 is preserved from annelids to mammals but is absent in pig Sus scrofa domesticus

    Mitochondrion

    (2011)
  • I. Banmeyer et al.

    Human mitochondrial peroxiredoxin 5 protects from mitochondrial DNA damages induced by hydrogen peroxide

    FEBS Lett.

    (2005)
  • H. Zhang et al.

    Mitochondrial thioredoxin-2/peroxiredoxin-3 system functions in parallel with mitochondrial GSH system in protection against oxidative stress

    Arch. Biochem. Biophys.

    (2007)
  • J. Rydstrom

    Mitochondrial NADPH, transhydrogenase and disease

    Biochim. Biophys. Acta

    (2006)
  • J.H. Lee et al.

    Inactivation of NADP+−dependent isocitrate dehydrogenase by peroxynitrite. Implication in cytotoxicity and alcohol-induced liver injury

    J. Biol. Chem.

    (2003)
  • J.L. Moon et al.

    Regulation of brefeldin A-induced ER stress and apoptosis by mitochondrial NADP(+)-dependent isocitrate dehydrogenase

    Biochem. Biophys. Res. Commun.

    (2012)
  • I.S. Kil et al.

    Small interfering RNA-mediated silencing of mitochondrial NADP+-dependent isocitrate dehydrogenase enhances the sensitivity of HeLa cells toward tumor necrosis factor-alpha and anticancer drugs

    Free Radic. Biol. Med.

    (2007)
  • L. Dang et al.

    IDH mutations in glioma and acute myeloid leukemia

    Trends Mol. Med.

    (2010)
  • Z. Chen et al.

    Enrichment and functional reconstitution of glutathione transport activity from rabbit kidney mitochondria: further evidence for the role of the dicarboxylate and 2-oxoglutarate carriers in mitochondrial glutathione transport

    Arch. Biochem. Biophys.

    (2000)
  • O. Coll et al.

    Sensitivity of the 2-oxoglutarate carrier to alcohol intake contributes to mitochondrial glutathione depletion

    Hepatology

    (2003)
  • H.M. Wilkins et al.

    Bcl-2 is a novel interacting partner for the 2-oxoglutarate carrier and a key regulator of mitochondrial glutathione

    Free Radic. Biol. Med.

    (2012)
  • M.L. Circu et al.

    Contribution of mitochondrial GSH transport to matrix GSH status and colonic epithelial cell apoptosis

    Free Radic. Biol. Med.

    (2008)
  • J. Garcia et al.

    Regulation of mitochondrial glutathione redox status and protein glutathionylation by respiratory substrates

    J. Biol. Chem.

    (2010)
  • A.K. Zimmermann et al.

    Glutathione binding to the Bcl-2 homology-3 domain groove: a molecular basis for Bcl-2 antioxidant function at mitochondria

    J. Biol. Chem.

    (2007)
  • J.M. Lluis et al.

    Acetaldehyde impairs mitochondrial glutathione transport in HepG2 cells through endoplasmic reticulum stress

    Gastroenterology

    (2003)
  • J. Montero et al.

    Cholesterol and peroxidized cardiolipin in mitochondrial membrane properties, permeabilization and cell death

    Biochim. Biophys. Acta

    (2010)
  • J.M. Lluis et al.

    Critical role of mitochondrial glutathione in the survival of hepatocytes during hypoxia

    J. Biol. Chem.

    (2005)
  • C. Lu et al.

    Role of calcium and cyclophilin D in the regulation of mitochondrial permeabilization induced by glutathione depletion

    Biochem. Biophys. Res. Commun.

    (2007)
  • M. Mari et al.

    Mitochondrial free cholesterol loading sensitizes to TNF- and Fas-mediated steatohepatitis

    Cell Metab.

    (2006)
  • M. Mari et al.

    Mechanism of mitochondrial glutathione-dependent hepatocellular susceptibility to TNF despite NF-kappaB activation

    Gastroenterology

    (2008)
  • C. Garcia-Ruiz et al.

    Trafficking of ganglioside GD3 to mitochondria by tumor necrosis factor-alpha

    J. Biol. Chem.

    (2002)
  • S. Krahenbuhl et al.

    Reduced antioxidative capacity in liver mitochondria from bile duct ligated rats

    Hepatology

    (1995)
  • S.H. Kaufmann et al.

    Induction of apoptosis by cancer chemotherapy

    Exp. Cell Res.

    (2000)
  • G.Q. Wang et al.

    A role for mitochondrial Bak in apoptotic response to anticancer drugs

    J. Biol. Chem.

    (2001)
  • M.P. Boldin et al.

    Involvement of MACH, a novel MORT1/FADD-interacting protease, in Fas/APO-1- and TNF receptor-induced cell death

    Cell

    (1996)
  • M. Muzio et al.

    FLICE, a novel FADD-homologous ICE/CED-3-like protease, is recruited to the CD95 (Fas/APO-1) death–inducing signaling complex

    Cell

    (1996)
  • P. Li et al.

    Cytochrome c and dATP-dependent formation of Apaf-1/caspase-9 complex initiates an apoptotic protease cascade

    Cell

    (1997)
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