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Free Radical Biology and Medicine (FRBM)

Role of glutathione in the regulation of epigenetic mechanisms in disease

Publication date: November 2017 Source:Free Radical Biology and Medicine, Volume 112 Author(s): José Luis García-Giménez, Carlos Romá-Mateo, Gisselle Pérez-Machado, Lorena Peiró-Chova, Federico V. Pallardó Epigenetics is a rapidly growing field that studies gene expression modifications not involving changes in the DNA sequence. Histone H3, one of the basic proteins in the nucleosomes that make up chromatin, is S-glutathionylated in mammalian cells and tissues, making Gamma-L-glutamyl-L-cysteinylglycine, glutathione (GSH), a physiological antioxidant and second messenger in cells, a new post-translational modifier of the histone code that alters the structure of the nucleosome. However, the role of GSH in the epigenetic mechanisms likely goes beyond a mere structural function. Evidence supports the hypothesis that there is a link between GSH metabolism and the control of epigenetic mechanisms at different levels (i.e., substrate availability, enzymatic activity for DNA methylation, changes in the expression of microRNAs, and participation in the histone code). However, little is known about the molecular pathways by which GSH can control epigenetic events. Studying mutations in enzymes involved in GSH metabolism and the alterations of the levels of cofactors affecting epigenetic mechanisms appears challenging. However, the number of diseases induced by aberrant epigenetic regulation is growing, so elucidating the intricate network between GSH metabolism, oxidative stress and epigenetics could shed light on how their deregulation contributes to the development of neurodegeneration, cancer, metabolic pathologies and many other types of diseases. Graphical abstract

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Glutathione peroxidase 4-catalyzed reduction of lipid hydroperoxides in membranes: The polar head of membrane phospholipids binds the enzyme and addresses the fatty acid hydroperoxide group toward the redox center

Publication date: November 2017 Source:Free Radical Biology and Medicine, Volume 112 Author(s): Giorgio Cozza, Monica Rossetto, Valentina Bosello-Travain, Matilde Maiorino, Antonella Roveri, Stefano Toppo, Mattia Zaccarin, Lucio Zennaro, Fulvio Ursini GPx4 is a monomeric glutathione peroxidase, unique in reducing the hydroperoxide group (-OOH) of fatty acids esterified in membrane phospholipids. This reaction inhibits lipid peroxidation and accounts for enzyme's vital role. Here we investigated the interaction of GPx4 with membrane phospholipids. A cationic surface near the GPx4 catalytic center interacts with phospholipid polar heads. Accordingly, SPR analysis indicates cardiolipin as the phospholipid with maximal affinity to GPx4. Consistent with the electrostatic nature of the interaction, KCl increases the KD. Molecular dynamic (MD) simulation shows that a -OOH posed in the core of the membrane as 13 - or 9 -OOH of tetra-linoleoyl cardiolipin or 15 -OOH stearoyl-arachidonoyl-phosphaphatidylcholine moves to the lipid-water interface. Thereby, the -OOH groups are addressed toward the GPx4 redox center. In this pose, however, the catalytic site facing the membrane would be inaccessible to GSH, but the consecutive redox processes facilitate access of GSH, which further primes undocking of the enzyme, because GSH competes for the binding residues implicated in docking. During the final phase of the catalytic cycle, while GSSG is produced, GPx4 is disconnected from the membrane. The observation that GSH depletion in cells induces GPx4 translocation to the membrane, is in agreement with this concept. Graphical abstract

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Assessment of glutathione/glutathione disulphide ratio and S-glutathionylated proteins in human blood, solid tissues, and cultured cells

Publication date: November 2017 Source:Free Radical Biology and Medicine, Volume 112 Author(s): Daniela Giustarini, Graziano Colombo, Maria Lisa Garavaglia, Emanuela Astori, Nicola Marcello Portinaro, Francesco Reggiani, Salvatore Badalamenti, Anna Maria Aloisi, Annalisa Santucci, Ranieri Rossi, Aldo Milzani, Isabella Dalle-Donne Glutathione (GSH) is the major non-protein thiol in humans and other mammals, which is present in millimolar concentrations within cells, but at much lower concentrations in the blood plasma. GSH and GSH-related enzymes act both to prevent oxidative damage and to detoxify electrophiles. Under oxidative stress, two GSH molecules become linked by a disulphide bridge to form glutathione disulphide (GSSG). Therefore, assessment of the GSH/GSSG ratio may provide an estimation of cellular redox metabolism. Current evidence resulting from studies in human blood, solid tissues, and cultured cells suggests that GSH also plays a prominent role in protein redox regulation via S -glutathionylation, i.e., the conjugation of GSH to reactive protein cysteine residues. A number of methodologies that enable quantitative analysis of GSH/GSSG ratio and S-glutathionylated proteins (PSSG), as well as identification and visualization of PSSG in tissue sections or cultured cells are currently available. Here, we have considered the main methodologies applied for GSH, GSSG and PSSG detection in biological samples. This review paper provides an up-to-date critical overview of the application of the most relevant analytical, morphological, and proteomics approaches to detect and analyse GSH, GSSG and PSSG in mammalian samples as well as discusses their current limitations. Graphical abstract

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Linking arsenite- and cadmium-generated oxidative stress to microsatellite instability in vitro and in vivo

Publication date: November 2017 Source:Free Radical Biology and Medicine, Volume 112 Author(s): Chang-Lin Wu, Li-Yan Huang, Christina L. Chang Mismatch repair (MMR) corrects replicative errors and minimizes DNA damage that occurs frequently in microsatellites. MMR deficiency is manifested as microsatellite instability (MSI), which contributes to hypermutability and cancer pathogenesis. Genomic instability, including MSI and chromosomal instability, appears to be responsible for the carcinogenesis of arsenic and cadmium, common contaminants in our environment. However, few studies have addressed arsenic- or cadmium-induced MSI, especially its potential link with arsenic- or cadmium-generated oxidative stress, due to the lack of quantifiable MSI assays and cost-effective animal models. Here, using a dual-fluorescent reporter, we demonstrate that sub-lethal doses of cadmium or arsenite, but not arsenate, increased the MSI frequency in human colorectal cancer cells. Arsenite- and cadmium-induced MSI occurred concomitantly with increased levels of reactive species and oxidative DNA damage, and with decreased levels of MMR proteins. However, N-acetyl-l-cysteine (NAC) suppressed arsenite- and cadmium-induced MSI and oxidative stress while restoring the levels of MMR proteins in the cells. Similarly, MSI was induced separately by arsenite and cadmium, and suppressed by NAC, in zebrafish in a fluorescinated PCR-based assay with newly-developed microsatellite markers and inter-segmental comparisons. Of five selected antioxidants examined, differential effects were exerted on the MSI induction and cytotoxicity of both arsenite and cadmium. Compared to MMR-proficient cells, MMR-deficient cells were more resistant to arsenic-mediated and cadmium-mediated cytotoxicity. Our findings demonstrate a novel linkage between arsenite-generated and cadmium-generated oxidative stress and MSI induction. Our findings also caution that antioxidants must be individually validated before being used for preventing arsenite- and c

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Rifampicin-induced injury in HepG2 cells is alleviated by TUDCA via increasing bile acid transporters expression and enhancing the Nrf2-mediated adaptive response

Publication date: November 2017 Source:Free Radical Biology and Medicine, Volume 112 Author(s): Weiping Zhang, Lihong Chen, Hui Feng, Wei Wang, Yi Cai, Fen Qi, Xiaofang Tao, Jun Liu, Yujun Shen, Xiaofei Ren, Xi Chen, Jianming Xu, Yuxian Shen Bile acid transporters and the nuclear factor erythroid 2-related factor (Nrf-2)-mediated adaptive response play important roles in the development of drug-induced liver injury (DILI). However, little is known about the contribution of the adaptive response to rifampicin (RFP)-induced cell injury. In this study, we found RFP decreased the survival rate of HepG2 cells and increased the levels of lactate dehydrogenase (LDH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP), γ-glutamyl-transferase (γ-GT), total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IBIL), total bile acid (TBA) and adenosine triphosphate (ATP) in the cell culture supernatants in both a concentration- and a time-dependent manner. RFP increased the expression levels of bile acid transporter proteins and mRNAs, such as bile salt export pump (BSEP), multidrug resistance protein 1 (MDR1), multidrug resistance-associated protein 2 (MRP2), Na+/taurocholate cotransporter (NTCP), organic anion transporting protein 2 (OATP2), organic solute transporter β (OSTβ) and Nrf2. Following the transient knockdown of Nrf2 and treatment with RFP, the expression levels of the BSEP, MDR1, MRP2, NTCP, OATP2 and OSTβ proteins and mRNAs were decreased to different degrees. Moreover, the cell survival was decreased, whereas the LDH level in the cell culture supernatant was increased. Overexpression of the Nrf2 gene produced the opposite effects. Treatment with tauroursodeoxycholic acid (TUDCA) increased the expression levels of the bile acid transporters and Nrf2, decreased the expression levels of glucose-regulated protein 78 (GRP78), PKR-like ER kinase (PERK), activating transcription factor 4 (ATF4), and C/EBP-homologous protein (CHOP),

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Redox Biology

Carnosine attenuates cyclophosphamide-induced bone marrow suppression by reducing oxidative DNA damage

Publication date: April 2018 Source:Redox Biology, Volume 14 Author(s): Jie Deng, Yi-Fei Zhong, Yan-Ping Wu, Zhuo Luo, Yuan-Ming Sun, Guo-En Wang, Hiroshi Kurihara, Yi-Fang Li, Rong-Rong He Oxidative DNA damage in bone marrow cells is the main side effect of chemotherapy drugs including cyclophosphamide (CTX). However, not all antioxidants are effective in inhibiting oxidative DNA damage. In this study, we report the beneficial effect of carnosine (β-alanyl-l-histidine), a special antioxidant with acrolein-sequestering ability, on CTX-induced bone marrow cell suppression. Our results show that carnosine treatment (100 and 200mg/kg, i.p.) significantly inhibited the generation of reactive oxygen species (ROS) and 8-hydroxy-2′-deoxyguanosine (8-oxo-dG), and decreased chromosomal abnormalities in the bone marrow cells of mice treated with CTX (20mg/kg, i.v., 24h). Furthermore, carnosine evidently mitigated CTX-induced G2/M arrest in murine bone marrow cells, accompanied by reduced ratios of p-Chk1/Chk1 and p-p53/p53 as well as decreased p21 expression. In addition, cell apoptosis caused by CTX was also suppressed by carnosine treatment, as assessed by decreased TUNEL-positive cell counts, down-regulated expressions of Bax and Cyt c, and reduced ratios of cleaved Caspase-3/Caspase-3. These results together suggest that carnosine can protect murine bone marrow cells from CTX-induced DNA damage via its antioxidant activity. Graphical abstract

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Blood-based bioenergetic profiling: A readout of systemic bioenergetic capacity that is related to differences in body composition

Publication date: October 2017 Source:Redox Biology, Volume 13 Author(s): Anthony J.A. Molina

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Quantitative biology of hydrogen peroxide signaling

Publication date: October 2017 Source:Redox Biology, Volume 13 Author(s): Fernando Antunes, Paula Matos Brito Hydrogen peroxide (H2O2) controls signaling pathways in cells by oxidative modulation of the activity of redox sensitive proteins denominated redox switches. Here, quantitative biology concepts are applied to review how H2O2 fulfills a key role in information transmission. Equations described lay the foundation of H2O2 signaling, give new insights on H2O2 signaling mechanisms, and help to learn new information from common redox signaling experiments. A key characteristic of H2O2 signaling is that the ratio between reduction and oxidation of redox switches determines the range of H2O2 concentrations to which they respond. Thus, a redox switch with low H2O2-dependent oxidability and slow reduction rate responds to the same range of H2O2 concentrations as a redox switch with high H2O2-dependent oxidability, but that is rapidly reduced. Yet, in the first case the response time is slow while in the second case is rapid. H2O2 sensing and transmission of information can be done directly or by complex mechanisms in which oxidation is relayed between proteins before oxidizing the final regulatory redox target. In spite of being a very simple molecule, H2O2 has a key role in cellular signaling, with the reliability of the information transmitted depending on the inherent chemical reactivity of redox switches, on the presence of localized H2O2 pools, and on the molecular recognition between redox switches and their partners. Graphical abstract

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Direct 1O2 optical excitation: A tool for redox biology

Publication date: October 2017 Source:Redox Biology, Volume 13 Author(s): Alfonso Blázquez-Castro Molecular oxygen (O2) displays very interesting properties. Its first excited state, commonly known as singlet oxygen (1O2), is one of the so-called Reactive Oxygen Species (ROS). It has been implicated in many redox processes in biological systems. For many decades its role has been that of a deleterious chemical species, although very positive clinical applications in the Photodynamic Therapy of cancer (PDT) have been reported. More recently, many ROS, and also 1O2, are in the spotlight because of their role in physiological signaling, like cell proliferation or tissue regeneration. However, there are methodological shortcomings to properly assess the role of 1O2 in redox biology with classical generation procedures. In this review the direct optical excitation of O2 to produce 1O2 will be introduced, in order to present its main advantages and drawbacks for biological studies. This photonic approach can provide with many interesting possibilities to understand and put to use ROS in redox signaling and in the biomedical field. Graphical abstract

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European contribution to the study of ROS: A summary of the findings and prospects for the future from the COST action BM1203 (EU-ROS)

Publication date: October 2017 Source:Redox Biology, Volume 13 Author(s): Javier Egea, Isabel Fabregat, Yves M. Frapart, Pietro Ghezzi, Agnes Görlach, Thomas Kietzmann, Kateryna Kubaichuk, Ulla G. Knaus, Manuela G. Lopez, Gloria Olaso-Gonzalez, Andreas Petry, Rainer Schulz, Jose Vina, Paul Winyard, Kahina Abbas, Opeyemi S. Ademowo, Catarina B. Afonso, Ioanna Andreadou, Haike Antelmann, Fernando Antunes, Mutay Aslan, Markus M. Bachschmid, Rui M. Barbosa, Vsevolod Belousov, Carsten Berndt, David Bernlohr, Esther Bertrán, Alberto Bindoli, Serge P. Bottari, Paula M. Brito, Guia Carrara, Ana I. Casas, Afroditi Chatzi, Niki Chondrogianni, Marcus Conrad, Marcus S. Cooke, João G. Costa, Antonio Cuadrado, Pham My-Chan Dang, Barbara De Smet, Bilge Debelec–Butuner, Irundika H.K. Dias, Joe Dan Dunn, Amanda J. Edson, Mariam El Assar, Jamel El-Benna, Péter Ferdinandy, Ana S. Fernandes, Kari E. Fladmark, Ulrich Förstermann, Rashid Giniatullin, Zoltán Giricz, Anikó Görbe, Helen Griffiths, Vaclav Hampl, Alina Hanf, Jan Herget, Pablo Hernansanz-Agustín, Melanie Hillion, Jingjing Huang, Serap Ilikay, Pidder Jansen-Dürr, Vincent Jaquet, Jaap A. Joles, Balaraman Kalyanaraman, Danylo Kaminskyy, Mahsa Karbaschi, Marina Kleanthous, Lars-Oliver Klotz, Bato Korac, Kemal Sami Korkmaz, Rafal Koziel, Damir Kračun, Karl-Heinz Krause, Vladimír Křen, Thomas Krieg, João Laranjinha, Antigone Lazou, Huige Li, Antonio Martínez-Ruiz, Reiko Matsui, Gethin J. McBean, Stuart P. Meredith, Joris Messens, Verónica Miguel, Yuliya Mikhed, Irina Milisav, Lidija Milković, Antonio Miranda-Vizuete, Miloš Mojović, María Monsalve, Pierre-Alexis Mouthuy, John Mulvey, Thomas Münzel, Vladimir Muzykantov, Isabel T.N. Nguyen, Matthias Oelze, Nuno G. Oliveira, Carlos M. Palmeira, Nikoletta Papaevgeniou, Aleksandra Pavićević, Brandán Pedre, Fabienne Peyrot, Mari

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