Overexpression of glutaredoxin 2 attenuates apoptosis by preventing cytochrome c release

Enoksson, Mari; Fernandes, Aristi P.; Prast, Stefanie; Lillig, Christopher Horst; Holmgren, Arne; Orrenius, Sten

doi:10.1016/j.bbrc.2004.12.067

Cited by 147 publications

(105 citation statements)

References 27 publications

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“…Depletion of mitochondrial GSH also potentiated peroxide accumulation and sensitized cells to cell death (8,157). Small interferring RNA (siRNA) for Grx-2 increased sensitivity to doxorubicin, whereas overexpression of mitochondrial Grx-2 inhibited cardiolipin loss and prevented apoptosis induced by doxorubicin (41,111). Because Trx and GSH protect against two-electron oxidants, this in vitro research points to the plausibility of oxidant-induce cell death mechanisms signaled by nonradical reactions, which disrupt redox control.…”

Section: Oxidative Stress As a Disruption Of Redox Signaling And Controlmentioning

confidence: 82%

Radical-free biology of oxidative stress

Jones¹

2008

American Journal of Physiology-Cell Physiology

1,020

839

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Free radical-induced macromolecular damage has been studied extensively as a mechanism of oxidative stress, but large-scale intervention trials with free radical scavenging antioxidant supplements show little benefit in humans. The present review summarizes data supporting a complementary hypothesis for oxidative stress in disease that can occur without free radicals. This hypothesis, which is termed the "redox hypothesis," is that oxidative stress occurs as a consequence of disruption of thiol redox circuits, which normally function in cell signaling and physiological regulation. The redox states of thiol systems are sensitive to twoelectron oxidants and controlled by the thioredoxins (Trx), glutathione (GSH), and cysteine (Cys). Trx and GSH systems are maintained under stable, but nonequilibrium conditions, due to a continuous oxidation of cell thiols at a rate of about 0.5% of the total thiol pool per minute. Redox-sensitive thiols are critical for signal transduction (e.g., H-Ras, PTP-1B), transcription factor binding to DNA (e.g., Nrf-2, nuclear factor-B), receptor activation (e.g., ␣IIb␤3 integrin in platelet activation), and other processes. Nonradical oxidants, including peroxides, aldehydes, quinones, and epoxides, are generated enzymatically from both endogenous and exogenous precursors and do not require free radicals as intermediates to oxidize or modify these thiols. Because of the nonequilibrium conditions in the thiol pathways, aberrant generation of nonradical oxidants at rates comparable to normal oxidation may be sufficient to disrupt function. Considerable opportunity exists to elucidate specific thiol control pathways and develop interventional strategies to restore normal redox control and protect against oxidative stress in aging and age-related disease.thioredoxin; glutathione; cysteine; hydrogen peroxide; redox signaling; protein thiol ONE OF THE GREAT REDOX BIOLOGISTS of the past century, Howard S. Mason, professed that to advance science, a scientist must interpret observations at the limit of their meaning. The present review of the redox biology of thiol systems addresses the possibility that disruption of the function and homeostasis of thiol systems is the most central feature of oxidative stress that contributes to mechanisms of aging and age-related disease. I have termed this the "redox hypothesis" to facilitate distinction from free radical hypotheses.Many proteins contain redox-sensitive thiols, and reactions of thiol systems occur largely by nonradical two-electron transfers. Accumulating data show that central thiol-disulfide couples are maintained under nonequilibrium conditions in biological systems. This presents a condition wherein changes in abundance and distribution of redox catalysts and changes in rates of generation of relevant oxidants (e.g., peroxides) and precursors for NADPH supply can account for pathological effects of oxidative stress through altered functions of enzymes, receptors, transporters, transcription factors, and structural elements, without free ra...

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Section: Oxidative Stress As a Disruption Of Redox Signaling And Controlmentioning

confidence: 82%

Radical-free biology of oxidative stress

Jones¹

2008

American Journal of Physiology-Cell Physiology

1,020

839

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“…PerkinElmer Life Sciences supplied the [4][5][6][7][8][9][10][11][12][13][14] C]Ch, glycerol tri- [9,10-3 H]oleate, and 1-palmitoyl-2-[1-…”

Section: Methodsmentioning

confidence: 99%

Permeabilization of the Mitochondrial Outer Membrane by Bax/Truncated Bid (tBid) Proteins as Sensitized by Cardiolipin Hydroperoxide Translocation

Korytowski

Basova

Piłat

et al. 2011

Journal of Biological Chemistry

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Cytochrome c (cyt c) release upon oxidation of cardiolipin (CL) in the mitochondrial inner membrane (IM) under oxidative stress occurs early in the intrinsic apoptotic pathway. We postulated that CL oxidation mobilizes not only cyt c but also CL itself in the form of hydroperoxide (CLOOH) species. Relatively hydrophilic CLOOHs could assist in apoptotic signaling by translocating to the outer membrane (OM), thus promoting recruitment of the pro-apoptotic proteins truncated Bid (tBid) and Bax for generation of cyt c-traversable pores. Initial testing of these possibilities showed that CLOOH-containing liposomes were permeabilized more readily by tBid plus Ca 2؉ than CL-containing counterparts. Moreover, CLOOH translocated more rapidly from IM-mimetic to OM-mimetic liposomes than CL and permitted more extensive OM permeabilization. We found that tBid bound more avidly to CLOOH-containing membranes than to CL counterparts, and binding increased with increasing CLOOH content. Permeabilization of CLOOH-containing liposomes in the presence of tBid could be triggered by monomeric Bax, consistent with tBid/Bax cooperation in pore formation. Using CL-null mitochondria from a yeast mutant, we found that tBid binding and cyt c release were dramatically enhanced by transfer acquisition of CLOOH. Additionally, we observed a pre-apoptotic IM-to-OM transfer of oxidized CL in cardiomyocytes treated with the Complex III blocker, antimycin A. These findings provide new mechanistic insights into the role of CL oxidation in the intrinsic pathway of oxidative apoptosis.Cytochrome c (cyt c) 2 dissociation from the mitochondrial inner membrane (IM), movement into the intermembrane space, and then release into cytosol is recognized as a key early event in the intrinsic (mitochondrion-initiated) pathway of oxidative stress-induced apoptosis (1-3). How this occurs is still not completely understood, but accumulating evidence suggests that oxidative modification of cardiolipin (CL), e.g. conversion to hydroperoxide species (CLOOHs), plays an important role (4 -7). CL (diphosphatidylglycerol) is located primarily in the mitochondrial IM of normal eukaryotic cells, where it interacts with and supports the functions of cyt c, Complex III (cytochromes b and c 1 ), and Complex IV (cytochrome c oxidase) (8). Unlike most other phospholipids in which only the sn-2 fatty acyl group is unsaturated, both sn-1 and sn-2 groups of natural CL are typically unsaturated. In mammalian heart, for example, tetra-linoleoyl CL composes 75-80% of overall CL molecular species (9). Consequently, CL oxidizability and -OOH content per average oxidized molecule are typically much higher than for more conventional phospholipids such as those in the phosphatidylcholine and phosphatidylethanolamine families. Model studies with bovine heart CL in thin film or liposomal form have shown that its normally strong interaction with some fraction of IM cyt c is progressively weakened with increasing -OOH content (4), suggesting possible involvement in pro-apoptotic cyt c releas...

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“…118 GRX2 has been shown to protect against apoptosis by reducing Cyt c release and cardiolipin oxidation. 119 Recently GRXs have been shown not only to deglutathionylate specific proteins but also to catalyze the glutathionylation of several proteins in the presence of GSK radicals. Hence, GRXs are capable of catalyzing both glutathionylation and deglutathionylation of proteins through distinct mechanisms.…”

Section: Figure 1 Apoptotic Signaling Pathways (See Text For Further mentioning

confidence: 99%

Apoptosis and glutathione: beyond an antioxidant

2009

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Apoptosis is a conserved homeostatic process critical for organ and tissue morphogenesis, development, and senescence. This form of programmed cell death also participates in the etiology of several human diseases including cancer, neurodegenerative, and autoimmune disorders. Although the signaling pathways leading to the progression of apoptosis have been extensively characterized, recent studies highlight the regulatory role of changes in the intracellular milieu (permissive apoptotic environment) in the efficient activation of the cell death machinery. In particular, glutathione (GSH) depletion is a common feature of apoptotic cell death triggered by a wide variety of stimuli including activation of death receptors, stress, environmental agents, and cytotoxic drugs. Although initial studies suggested that GSH depletion was only a byproduct of oxidative stress generated during cell death, recent discoveries suggest that GSH depletion and post-translational modifications of proteins through glutathionylation are critical regulators of apoptosis. Here, we reformulate these emerging paradigms into our current understanding of cell death mechanisms. Apoptosis or programmed cell death is a ubiquitous homeostatic process involved in numerous biological systems. Under physiological conditions it is critical not only in the turnover of cells in tissues but also during normal development and senescence. Moreover, its deregulation has been widely observed to occur as either a cause or consequence of distinct pathologies including cancer, autoimmune, and neurodegenerative diseases. Apoptosis is a highly organized program induced by a myriad of stimuli that are characterized by the progressive activation of precise pathways leading to specific biochemical and morphological alterations in individual cells without involving an inflammatory response. Early stages of apoptosis are characterized by initiator caspase activation, cell shrinkage, loss of plasma membrane lipid asymmetry, and chromatin condensation. The execution phase of apoptosis is characterized by activation of executioner caspases and endonucleases, apoptotic body formation, and cell fragmentation 1 (Figure 1). Interestingly, recent studies have shown that changes in the intracellular milieu of the cells, such as alterations in the redox environment, are important regulators of the progression to apoptosis. 2 These discoveries have lead to the concept of a permissive apoptotic environment necessary for the activation of the proper signaling pathways regulating apoptosis. Glutathione (GSH) depletion is an early hallmark in the progression of cell death in response to a variety of apoptotic stimuli in numerous cell types 3,4 (Figure 2), although the exact role of GSH depletion in apoptosis is still controversial. We review recent data that show new insights into the understanding of the causes and consequences that alterations in the redox environment of the cell have on apoptosis.The Role of GSH in the Regulation of Apoptosis GSH synthesis, depletion, and apopt...

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Overexpression of glutaredoxin 2 attenuates apoptosis by preventing cytochrome c release

Cited by 147 publications

References 27 publications

Radical-free biology of oxidative stress

Radical-free biology of oxidative stress

Permeabilization of the Mitochondrial Outer Membrane by Bax/Truncated Bid (tBid) Proteins as Sensitized by Cardiolipin Hydroperoxide Translocation

Apoptosis and glutathione: beyond an antioxidant

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