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Li N, Zhang S, Xiong F, Eizirik DL, Wang CY. SUMOylation, a multifaceted regulatory mechanism in the pancreatic beta cells. Semin Cell Dev Biol 2020; 103:51-58. [PMID: 32331991 DOI: 10.1016/j.semcdb.2020.03.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 01/03/2020] [Accepted: 03/23/2020] [Indexed: 12/19/2022]
Abstract
SUMOylation is an evolutionarily conserved post-translational modification (PTM) that regulates protein subcellular localization, stability, conformation, transcription and enzymatic activity. Recent studies indicate that SUMOylation plays a key role in insulin gene expression, glucose metabolism and insulin exocytosis under physiological conditions in the pancreatic beta cells. Furthermore, SUMOylation is implicated in beta cell survival and recovery following exposure to oxidative stress, ER stress and inflammatory mediators under pathological situations. SUMOylation is closely regulated by the cellular redox status, and it collaborates with other PTMs such as phosphorylation, ubiquitination, and NEDDylation, to maintain beta cellular homeostasis. We hereby provide an update on recent findings regarding the role of SUMOylation in the regulation of pancreatic beta cell viability and function, and discuss its potential implication in beta cell senescence and RNA processing (e.g., pre-mRNA splicing and mRNA methylation). Through which we intend to provide novel insights into this fundamental biological process regarding both maintenance of beta cell viability and functionality, and beta cell dysfunction in diabetes mellitus.
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Affiliation(s)
- Na Li
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Wuhan, China
| | - Shu Zhang
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Wuhan, China
| | - Fei Xiong
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Wuhan, China
| | - Decio L Eizirik
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 808 Route de Lennik, B-1070, Brussels, Belgium; Indiana Biosciences Research Institute (IBRI), Indianapolis, IN, USA.
| | - Cong-Yi Wang
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Wuhan, China.
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Abstract
Reactive oxygen species (ROS) are highly reactive oxygen derivatives. Initially, they were considered as metabolic by-products (of mitochondria in particular), which consistently lead to aging and disease. Over the last decades, however, it became increasingly apparent that virtually all eukaryotic cells possess specifically ROS-producing enzymes, namely, NOX NADPH oxidases. In most mammals, there are seven NOX isoforms: three closely related isoforms, NOX1, 2, 3, which are activated by cytoplasmic subunits; NOX4, which appears to be constitutively active; and the EF-hand-containing Ca2+-activated isoforms NOX5 and DUOX1 and 2. Loss-of-function mutations in NOX genes can lead to serious human disease. NOX2 deficiency leads to primary immune deficiency, while DUOX2 deficiency presents as congenital hypothyroidism. Nox-deficient mice provide important tools to explore the physiological functions of various NADPH oxidases as a loss of function in Nox2, Nox3, and Duox2 leads to a spontaneous phenotype. The genetic absence of Nox1, Nox4, and Duox1 does not result in an obvious mouse phenotype (the NOX5 gene is absent in rodents and can therefore not be studied using knockout mice). Since the discovery of the NOX family at the turn of the millennium, much progress in understanding the biochemistry and the physiology of NOX has been made; however many questions remain unanswered to date. This chapter is an overview of our present knowledge on mammalian NOX/DUOX enzymes.
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Affiliation(s)
- Hélène Buvelot
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
| | - Vincent Jaquet
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Karl-Heinz Krause
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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Wahab MH, Akoul ES, Abdel-Aziz AA. Modulatory Effects of Melatonin and Vitamin E on Doxorubicin-Induced Cardiotoxicity in Ehrlich Ascites Carcinoma-Bearing Mice. TUMORI JOURNAL 2018; 86:157-62. [PMID: 10855855 DOI: 10.1177/030089160008600210] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Doxorubicin (Dox), an anthracycline antibiotic, has a wide spectrum of antitumor activity with dose-limiting cardiotoxicity. The drug's toxicity is known to be closely related to the generation of active oxygen free radicals. In our study the normal cardiac tissue contents of total protein, glutathione (GSH) and malondialdehyde (MDA) were significantly decreased, by 25%, 33% and 92%, respectively, in the group of mice bearing Ehrlich ascites carcinoma (EAC) and treated with Dox (4 mg/kg/week x 2, ip). Administration of melatonin (5 mg/kg/day x 15, po) starting 24 hours prior to Dox treatment significantly increased the cardiac contents of total protein and GSH as well as the superoxide dismutase (SOD) activity, by 31%, 36% and 39%, respectively, compared to treatment with Dox only, while the content of MDA was decreased by 26%. Similarly, administration of vitamin E (250 mg/kg/day x 15, po) starting 24 hours prior to Dox treatment significantly increased the cardiac contents of total protein, GSH and SOD, by 23%, 26% and 42%, respectively, while the cardiac content of MDA was decreased by 35% compared with the Dox-only-treated group. As to the oncolytic activity of Dox, pretreatment of EAC-bearing mice with melatonin (5 mg/kg/day x 30, po) or vitamin E (250 mg/kg/day x 30, po) 24 hours prior to Dox administration (4 mg/kg/week x 4, ip) improved the antitumor activity of Dox as indicated by the increase in the average life span of the animals and the number of long-term survivors as well as the decrease in body weight loss induced by Dox treatment. It is clear from these results that administration of melatonin not only protects against the cardiotoxicity induced by Dox treatment but also enhances its antitumor activity to a more significant extent than does vitamin E.
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Affiliation(s)
- M H Wahab
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Al-Azhar University, Nasr City, Cairo, Egypt
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Indo HP, Yen HC, Nakanishi I, Matsumoto KI, Tamura M, Nagano Y, Matsui H, Gusev O, Cornette R, Okuda T, Minamiyama Y, Ichikawa H, Suenaga S, Oki M, Sato T, Ozawa T, Clair DKS, Majima HJ. A mitochondrial superoxide theory for oxidative stress diseases and aging. J Clin Biochem Nutr 2014; 56:1-7. [PMID: 25834301 PMCID: PMC4306659 DOI: 10.3164/jcbn.14-42] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 08/08/2014] [Indexed: 11/26/2022] Open
Abstract
Fridovich identified CuZnSOD in 1969 and manganese superoxide dismutase (MnSOD) in 1973, and proposed ”the Superoxide Theory,” which postulates that superoxide (O2•−) is the origin of most reactive oxygen species (ROS) and that it undergoes a chain reaction in a cell, playing a central role in the ROS producing system. Increased oxidative stress on an organism causes damage to cells, the smallest constituent unit of an organism, which can lead to the onset of a variety of chronic diseases, such as Alzheimer’s, Parkinson’s, amyotrophic lateral sclerosis and other neurological diseases caused by abnormalities in biological defenses or increased intracellular reactive oxygen levels. Oxidative stress also plays a role in aging. Antioxidant systems, including non-enzyme low-molecular-weight antioxidants (such as, vitamins A, C and E, polyphenols, glutathione, and coenzyme Q10) and antioxidant enzymes, fight against oxidants in cells. Superoxide is considered to be a major factor in oxidant toxicity, and mitochondrial MnSOD enzymes constitute an essential defense against superoxide. Mitochondria are the major source of superoxide. The reaction of superoxide generated from mitochondria with nitric oxide is faster than SOD catalyzed reaction, and produces peroxynitrite. Thus, based on research conducted after Fridovich’s seminal studies, we now propose a modified superoxide theory; i.e., superoxide is the origin of reactive oxygen and nitrogen species (RONS) and, as such, causes various redox related diseases and aging.
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Affiliation(s)
- Hiroko P Indo
- Department of Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan ; Department of Space Environmental Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan ; Graduate Center of Toxicology and Markey Cancer Center, University of Kentucky College of Medicine, Lexington, Kentucky 40506, USA
| | - Hsiu-Chuan Yen
- Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Kwei-Shan, Tao-Yuan 333, Taiwan
| | - Ikuo Nakanishi
- Radio-Redox-Response Research Team, Advanced Particle Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Ken-Ichiro Matsumoto
- Radio-Redox-Response Research Team, Advanced Particle Radiation Biology Research Program, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba 263-8555, Japan
| | - Masato Tamura
- Division of Gastroenterology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Yumiko Nagano
- Division of Gastroenterology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Hirofumi Matsui
- Division of Gastroenterology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Oleg Gusev
- Department of Invertebrates Zoology and Functional Morphology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremevskaya str., 17 Kazan 420-008, Russia ; Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, ISS Science Project Office, Ibaraki 305-8505, Japan ; Anhydrobiosis Research Unit, National Institute of Agrobiological Sciences, Ohwashi 1-2, Tsukuba, Ibaraki 305-8634, Japan
| | - Richard Cornette
- Anhydrobiosis Research Unit, National Institute of Agrobiological Sciences, Ohwashi 1-2, Tsukuba, Ibaraki 305-8634, Japan
| | - Takashi Okuda
- Anhydrobiosis Research Unit, National Institute of Agrobiological Sciences, Ohwashi 1-2, Tsukuba, Ibaraki 305-8634, Japan
| | - Yukiko Minamiyama
- Food Hygiene and Environmental Health Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Sakyo-ku, Kyoto 606-8522, Japan
| | - Hiroshi Ichikawa
- Department of Medical Life Systems, Graduate School of Life and Medical Sciences, Doshishia University, Kyoto 610-0394, Japan
| | - Shigeaki Suenaga
- Department of Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan
| | - Misato Oki
- Department of Space Environmental Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan
| | - Tsuyoshi Sato
- Department of Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan
| | - Toshihiko Ozawa
- Division of Oxidative Stress Research, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Daret K St Clair
- Graduate Center of Toxicology and Markey Cancer Center, University of Kentucky College of Medicine, Lexington, Kentucky 40506, USA
| | - Hideyuki J Majima
- Department of Oncology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan ; Department of Space Environmental Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan
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Hou CL, Zhang J, Liu XT, Liu H, Zeng XF, Qiao SY. Superoxide dismutase recombinant Lactobacillus fermentum ameliorates intestinal oxidative stress through inhibiting NF-κB activation in a trinitrobenzene sulphonic acid-induced colitis mouse model. J Appl Microbiol 2014; 116:1621-31. [PMID: 24484394 DOI: 10.1111/jam.12461] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 12/26/2013] [Accepted: 01/24/2014] [Indexed: 02/05/2023]
Abstract
AIMS Superoxide dismutase (SOD) can prevent and cure inflammatory bowel diseases by decreasing the amount of reactive oxygen species. Unfortunately, short half-life of SOD in the gastrointestinal tract limited its application in the intestinal tract. This study aimed to investigate the treatment effects of recombinant SOD Lactobacillus fermentum in a colitis mouse model. METHODS AND RESULTS In this study, we expressed the sodA gene in Lact. fermentum I5007 to obtain the SOD recombinant strain. Then, we determined the therapeutic effects of this SOD recombinant strain in a trinitrobenzene sulphonic acid (TNBS)-induced colitis mouse model. We found that SOD activity in the recombinant Lact. fermentum was increased by almost eightfold compared with that in the wild type. Additionally, both the wild type and the recombinant Lact. fermentum increased the numbers of lactobacilli in the colon of mice (P < 0·05). Colitis mice treated with recombinant Lact. fermentum showed a higher survival rate and lower disease activity index (P < 0·05). Recombinant Lact. fermentum significantly decreased colonic mucosa histological scoring for infiltration of inflammatory cells, lipid peroxidation, the expression of pro-inflammatory cytokines and myeloperoxidase (P < 0·05) and inhibited NF-κB activity in colitis mice (P < 0·05). CONCLUSIONS SOD recombinant Lact. fermentum significantly reduced oxidative stress and inflammation through inhibiting NF-κB activation in the TNBS-induced colitis model. SIGNIFICANCE AND IMPACT OF THE STUDY This study provides insights into the anti-inflammatory effects of SOD recombinant Lact. fermentum, indicating the potential therapeutic effects in preventing and curing intestinal bowel diseases.
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Affiliation(s)
- C L Hou
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
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Krishnamurthy A, Rathinasabapathi B. Oxidative stress tolerance in plants: novel interplay between auxin and reactive oxygen species signaling. PLANT SIGNALING & BEHAVIOR 2013; 8:doi: 10.4161/psb.25761. [PMID: 23887492 PMCID: PMC4091114 DOI: 10.4161/psb.25761] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Biotic and abiotic stress conditions produce reactive oxygen species (ROS) in plants causing oxidative stress damage. At the same time, ROS have additional signaling roles in plant adaptation to the stress. It is not known how the two seemingly contrasting functional roles of ROS between oxidative damage to the cell and signaling for stress protection are balanced. Research suggests that the plant growth regulator auxin may be the connecting link regulating the level of ROS and directing its role in oxidative damage or signaling in plants under stress. The objective of this review is to highlight some of the recent research on how auxin's role is intertwined to that of ROS, more specifically H2O2, in plant adaptation to oxidative stress conditions.
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Rostami R, Aghasi M, Mohammadi A, Nourooz-Zadeh J. Enhanced oxidative stress in Hashimoto's thyroiditis: Inter-relationships to biomarkers of thyroid function. Clin Biochem 2013; 46:308-12. [DOI: 10.1016/j.clinbiochem.2012.11.021] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 11/25/2012] [Accepted: 11/26/2012] [Indexed: 10/27/2022]
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Bae YS, Oh H, Rhee SG, Yoo YD. Regulation of reactive oxygen species generation in cell signaling. Mol Cells 2011; 32:491-509. [PMID: 22207195 PMCID: PMC3887685 DOI: 10.1007/s10059-011-0276-3] [Citation(s) in RCA: 450] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 12/12/2011] [Indexed: 12/19/2022] Open
Abstract
Reactive oxygen species (ROS) including superoxide anion and hydrogen peroxide (H(2)O(2)) are thought to be byproducts of aerobic respiration with damaging effects on DNA, protein, and lipid. A growing body of evidence indicates, however, that ROS are involved in the maintenance of redox homeostasis and various cellular signaling pathways. ROS are generated from diverse sources including mitochondrial respiratory chain, enzymatic activation of cytochrome p450, and NADPH oxidases further suggesting involvement in a complex array of cellular processes. This review summarizes the production and function of ROS. In particular, how cytosolic and membrane proteins regulate ROS generation for intracellular redox signaling will be detailed.
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Affiliation(s)
- Yun Soo Bae
- Department of Life Science, Division of Life and Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750, Korea
| | - Hyunjin Oh
- Department of Life Science, Division of Life and Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750, Korea
| | - Sue Goo Rhee
- Department of Life Science, Division of Life and Pharmaceutical Sciences, Ewha Womans University, Seoul 120-750, Korea
| | - Young Do Yoo
- Laboratory of Molecular Cell Biology, Graduate School of Medicine, Korea University College of Medicine, Korea University, Seoul 136-705, Korea
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HIV-1 gp120 induces antioxidant response element-mediated expression in primary astrocytes: role in HIV associated neurocognitive disorder. Neurochem Int 2011; 61:807-14. [PMID: 21756955 DOI: 10.1016/j.neuint.2011.06.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 06/06/2011] [Accepted: 06/18/2011] [Indexed: 11/22/2022]
Abstract
HIV infection affects the central nervous system resulting in HIV associated neurocognitive disorder (HAND), which is characterized by depression, behavioral and motor dysfunctions. The HIV-1 viral envelope protein gp120 is known to induce the release of neurotoxic factors which lead to apoptotic cell death. Although the exact mechanisms involved in HIV-1 gp120-induced neurotoxicity are not completely understood, oxidative stress is suggested to play a vital role in the neuropathogenesis of HAND. Astrocytes represent major population of the non-neuronal cell type in the brain and play a critical role in the neuropathogenesis of HAND. Increased oxidative stress is known to induce nuclear factor erythroid derived 2-related factor 2 (Nrf2), a basic leucine zipper transcription factor which is known to regulate the antioxidant defensive mechanism. However, the role of Nrf2 in HAND has not been elucidated. We report that gp120 significantly upregulates Nrf2 in human astrocytes and is associated with stimulation of key antioxidant defensive enzymes Hemoxygenase (HO-1) and NAD(P)H dehydrogenase quinone1 (Nqo1). Pretreatment of the astrocytes with antioxidants or a specific calcium chelator BAPTA-AM, significantly blocked the upregulation of Nrf2, HO-1 and Nqo1. These results suggest a possible role of the intracellular calcium and oxidative stress in Nrf2 mediated antioxidant defense mechanism, which may have protective role in promoting cell survival.
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Kovacic P, Edwards C. Integrated approach to the mechanisms of thyroid toxins: electron transfer, reactive oxygen species, oxidative stress, cell signaling, receptors, and antioxidants. J Recept Signal Transduct Res 2010; 30:133-42. [DOI: 10.3109/10799891003702678] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Xu Z, Chan HY, Lam WL, Lam KH, Lam LSM, Ng TB, Au SWN. SUMO proteases: redox regulation and biological consequences. Antioxid Redox Signal 2009; 11:1453-84. [PMID: 19186998 DOI: 10.1089/ars.2008.2182] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Small-ubiquitin modifier (SUMO) has emerged as a novel modification system that governs the activities of a wide spectrum of protein substrates. SUMO-specific proteases (SENP) are of particular interest, as they are responsible for both the maturation of SUMO precursors and for their deconjugation. The interruption of SENPs has been implicated in embryonic defects and carcinoma cells, indicating that a proper balance of SUMO conjugation and deconjugation is crucial. Recent advances in molecular and cellular biology have highlighted the distinct subcellular localization, and endopeptidase and isopeptidase activities of SENPs, suggesting that they are nonredundant. A better understanding of the molecular basis of SUMO recognition and hydrolytic cleavage has been obtained from the crystal structures of SENP-substrate complexes. While a number of proteomic studies have shown an upregulation of sumoylation, attention is now increasingly being directed towards the regulatory mechanism of sumoylation, in particular the oxidative effect. Findings on the oxidation-induced intermolecular disulfide of E1-E2 ligases and SENP1/2 have improved our understanding of the mechanism by which modification is switched up or down. More intriguingly, a growing body of evidence suggests that sumoylation cross-talks with other modifications, and that the upstream and downstream signaling pathway is co-regulated by more than one modifier.
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Affiliation(s)
- Zheng Xu
- Centre for Protein Science and Crystallography, Department of Biochemistry and Molecular Biotechnology Program, Faculty of Science, The Chinese University of Hong Kong, Hong Kong
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Jayakumar AR, Rama Rao KV, Tong XY, Norenberg MD. Calcium in the mechanism of ammonia-induced astrocyte swelling. J Neurochem 2009; 109 Suppl 1:252-7. [PMID: 19393035 DOI: 10.1111/j.1471-4159.2009.05842.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Brain edema, due largely to astrocyte swelling, is an important clinical problem in patients with acute liver failure. While mechanisms underlying astrocyte swelling in this condition are not fully understood, ammonia and associated oxidative/nitrosative stress appear to be involved. Mechanisms responsible for the increase in reactive oxygen/nitrogen species (RONS) and their role in ammonia-induced astrocyte swelling, however, are poorly understood. Recent studies have demonstrated a transient increase in intracellular Ca2+ in cultured astrocytes exposed to ammonia. As Ca2+ is a known inducer of RONS, we investigated potential mechanisms by which Ca2+ may be responsible for the production of RONS and cell swelling in cultured astrocytes after treatment with ammonia. Exposure of cultured astrocytes to ammonia (5 mM) increased the formation of free radicals, including nitric oxide, and such increase was significantly diminished by treatment with the Ca2+ chelator 1,2-bis-(o-aminophenoxy)-ethane-N,N,-N',N'-tetraacetic acid tetraacetoxy-methyl ester (BAPTA). We then examined the activity of Ca2+-dependent enzymes that are known to generate RONS and found that ammonia significantly increased the activities of NADPH oxidase (NOX), constitutive nitric oxide synthase (cNOS), and phospholipase A2 (PLA2) and such increases in activity were significantly diminished by BAPTA. Pre-treatment of cultures with 7-nitroindazole, apocyanin, and quinacrine, respective inhibitors of cNOS, NOX, and PLA2, all significantly diminished RONS production. Additionally, treatment of cultures with BAPTA or with inhibitors of cNOS, NOX, and PLA2 reduced ammonia-induced astrocyte swelling. These studies suggest that the ammonia-induced rise in intracellular Ca2+ activates free radical producing enzymes that ultimately contribute to the mechanism of astrocyte swelling.
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Abstract
Iodination of thyroglobulin is the key step of thyroid hormone biosynthesis. It is catalyzed by thyroid peroxidase and occurs within the follicular space at the apical plasma membrane. Hydrogen peroxide produced by thyrocytes as an oxidant for iodide may compromise cellular and genomic integrity of the surrounding cells, unless these are sufficiently protected by peroxidases. Thus, peroxidases play two opposing roles in thyroid biology. Both aspects of peroxide biology in the thyroid are separated in space and time and respond to the different physiological states of the thyrocytes. Redox-protective peroxidases in the thyroid are peroxiredoxins, glutathione peroxidases, and catalase. Glutathione peroxidases are selenoenzymes, whereas selenium-independent peroxiredoxins are functionally linked to the selenoenzymes of the thioredoxin reductase family through their thioredoxin cofactors. Thus, selenium impacts directly and indirectly on protective enzymes in the thyroid, a link that has been supported by animal experiments and clinical observations. In view of this relationship, it is remarkable that rather little is known about selenoprotein expression and their potential functional roles in the thyroid. Moreover, selenium-dependent and -independent peroxidases have rarely been examined in the same studies. Therefore, we review the relevant literature and present expression data of both selenium-dependent and -independent peroxidases in the murine thyroid.
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Affiliation(s)
- Ulrich Schweizer
- Institute of Experimental Endocrinology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
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Gao YT, Roman LJ, Martásek P, Panda SP, Ishimura Y, Masters BSS. Oxygen metabolism by endothelial nitric-oxide synthase. J Biol Chem 2007; 282:28557-28565. [PMID: 17698846 DOI: 10.1074/jbc.m704890200] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nitric-oxide synthase (NOS) catalyzes both coupled and uncoupled reactions that generate nitric oxide and reactive oxygen species. Oxygen is often the overlooked substrate, and the oxygen metabolism catalyzed by NOS has been poorly defined. In this paper we focus on the oxygen stoichiometry and effects of substrate/cofactor binding on the endothelial NOS isoform (eNOS). In the presence of both L-arginine and tetrahydrobiopterin, eNOS is highly coupled (>90%), and the measured stoichiometry of O(2)/NADPH is very close to the theoretical value. We report for the first time that the presence of L-arginine stimulates oxygen uptake by eNOS. The fact that nonhydrolyzable L-arginine analogs are not stimulatory indicates that the occurrence of the coupled reaction, rather than the accelerated uncoupled reaction, is responsible for the L-arginine-dependent stimulation. The presence of 5,6,7,8-tetrahydrobiopterin quenched the uncoupled reactions and resulted in much less reactive oxygen species formation, whereas the presence of redox-incompetent 7,8-dihydrobiopterin demonstrates little quenching effect. These results reveal different mechanisms for oxygen metabolism for eNOS as opposed to nNOS and, perhaps, partially explain their functional differences.
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Affiliation(s)
- Ying Tong Gao
- Department of Biochemistry, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900
| | - Linda J Roman
- Department of Biochemistry, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900
| | - Pavel Martásek
- Department of Pediatrics, Charles University School of Medicine I, 128 08 Prague, Czech Republic
| | - Satya Prakash Panda
- Department of Biochemistry, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900
| | - Yuzuru Ishimura
- Department of Biochemistry and Integrated Biology, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Bettie Sue S Masters
- Department of Biochemistry, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900.
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Bedard K, Krause KH. The NOX family of ROS-generating NADPH oxidases: physiology and pathophysiology. Physiol Rev 2007; 87:245-313. [PMID: 17237347 DOI: 10.1152/physrev.00044.2005] [Citation(s) in RCA: 4878] [Impact Index Per Article: 286.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
For a long time, superoxide generation by an NADPH oxidase was considered as an oddity only found in professional phagocytes. Over the last years, six homologs of the cytochrome subunit of the phagocyte NADPH oxidase were found: NOX1, NOX3, NOX4, NOX5, DUOX1, and DUOX2. Together with the phagocyte NADPH oxidase itself (NOX2/gp91(phox)), the homologs are now referred to as the NOX family of NADPH oxidases. These enzymes share the capacity to transport electrons across the plasma membrane and to generate superoxide and other downstream reactive oxygen species (ROS). Activation mechanisms and tissue distribution of the different members of the family are markedly different. The physiological functions of NOX family enzymes include host defense, posttranlational processing of proteins, cellular signaling, regulation of gene expression, and cell differentiation. NOX enzymes also contribute to a wide range of pathological processes. NOX deficiency may lead to immunosuppresion, lack of otoconogenesis, or hypothyroidism. Increased NOX activity also contributes to a large number or pathologies, in particular cardiovascular diseases and neurodegeneration. This review summarizes the current state of knowledge of the functions of NOX enzymes in physiology and pathology.
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Affiliation(s)
- Karen Bedard
- Biology of Ageing Laboratories, University of Geneva, Geneva, Switzerland
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Gao YT, Panda SP, Roman LJ, Martásek P, Ishimura Y, Masters BSS. Oxygen metabolism by neuronal nitric-oxide synthase. J Biol Chem 2007; 282:7921-9. [PMID: 17229730 DOI: 10.1074/jbc.m609814200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Nitric-oxide synthases (NOS) catalyze nitric oxide (NO) formation from the amino acid L-arginine. NOS is known to catalyze more than one reaction: the NO-producing reaction is considered to be the coupled reaction, and the uncoupled reactions are those that produce reactive (reduced) oxygen species (ROS), such as superoxide anion (O-2.) and/or hydrogen peroxide (H2O2). As an oxygenase, NOS has been known for more than two decades, yet there is no complete description of oxygen stoichiometry. The present paper is focused on oxygen stoichiometry and the effects of cofactor binding on the neuronal isoform (nNOS) on oxygen uptake and product formation. Products of the uncoupled reactions are analyzed using diacetyldeuteroheme-substituted horseradish peroxidase as a trapping agent for both O-2. and H2O2. The addition of calmodulin not only stimulated the oxygen uptake rate but also changed the product of the uncoupled reaction, supporting the possibility of two different sites for electron leakage to molecular oxygen. Quantitative analysis of the uncoupled (substrate-free) reaction revealed a stoichiometry close to the theoretical value, and adding L-arginine not only initiates the coupled reaction, but also inhibits oxygen uptake. The presence of tetrahydrobiopterin affects oxygen metabolism by lowering the apparent Km value of nNOS for oxygen in the uncoupled reaction.
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Affiliation(s)
- Ying Tong Gao
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229-3900, USA
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17
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Iwase K, Nagasaka A, Kato K, Itoh A, Jimbo S, Hibi Y, Kobayashi N, Yamamoto H, Seko T, Miura K. Cu/Zn- and Mn-Superoxide Dismutase Distribution and Concentration in Adrenal Tumors. J Surg Res 2006; 135:150-5. [PMID: 16780879 DOI: 10.1016/j.jss.2006.03.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Revised: 02/27/2006] [Accepted: 03/13/2006] [Indexed: 10/24/2022]
Abstract
The tissue distribution of Cu/Zn- and Mn-superoxide dismutases (SOD) in adrenal tumors was studied by an immunohistochemical technique, and the concentrations of both SODs were measured by a sensitive sandwich enzyme immunoassay technique. In the normal adrenal gland, both Cu/Zn- and Mn-SODs were localized predominantly in the reticular zone of the cortex. Cu/Zn-SOD was stained clearly in the inner fascicular zone of the cortex, but not in the medulla, whereas Mn-SOD was stained weakly in the medulla. In different adrenal tumors, the localization of both stained SODs reflected the origin of the tumor cell. Thus, in one section of a pheochromocytoma only Mn-SOD was stained clearly. The concentrations of both SODs in the tissues of medullary tumors were lower than those in the normal adrenal gland and adrenocortical adenomas. The concentration of Cu/Zn-SOD in the tumor tissue of Cushing's syndrome adenoma was higher, and that of Mn-SOD was lower than the concentrations in the normal adrenal gland. The ratio of the tissue concentrations of Mn-SOD to Cu/Zn-SOD was lower in adrenal medullary tumors and Cushing's syndrome adenomas than in the normal adrenal gland and primary aldosteronism adenomas, indicating the predominance of Cu/Zn-SOD in the former, and Mn-SOD in the latter. These data suggest that the localization of Cu/Zn- and Mn-SODs in adrenal tissues reflects the specificity of the adrenal cells that produce the tissue-specific hormones. An investigation of changes in these enzymes in adrenal tumors may also provide useful information on adrenal tumor cell differentiation.
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Affiliation(s)
- Katsumi Iwase
- Department of Surgery, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan.
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18
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Abstract
The dual oxidases (DUOXes) 1 and 2 are named based on their having both a domain homologous to the NADPH-oxidase of the phagocyte NADPH-oxidase gp91( phox )/NOX2 and a domain homologous to thyroid peroxidase. The DUOX1 and DUOX2 mRNAs were originally cloned from thyroid tissue, and the corresponding proteins were recognized as intricate components of the thyroid hormone synthesis process, providing hydrogen peroxide essential for the organification of iodide. The function of DUOX2 in thyroid hormonogenesis has been firmly established by linking the congenital hypothyroid phenotype "total iodide organification defect" to biallelic inactivating DUOX2 mutations. Based on the expression of both DUOXes in combination with a peroxidase in a range of different tissues and functional studies; the concept evolves that DUOX is important not only for thyroid hormonogenesis but also as an integral part of the host defense system of mucosal surfaces, participates in the control of epithelial infection, augments surface B-cell receptor signaling in lymphocytes, and is involved in generating a respiratory burst at fertilization.
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19
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Ameziane-El-Hassani R, Morand S, Boucher JL, Frapart YM, Apostolou D, Agnandji D, Gnidehou S, Ohayon R, Noël-Hudson MS, Francon J, Lalaoui K, Virion A, Dupuy C. Dual oxidase-2 has an intrinsic Ca2+-dependent H2O2-generating activity. J Biol Chem 2005; 280:30046-54. [PMID: 15972824 DOI: 10.1074/jbc.m500516200] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Duox2 (and probably Duox1) is a glycoflavoprotein involved in thyroid hormone biosynthesis, as the thyroid H2O2 generator functionally associated with Tpo (thyroperoxidase). So far, because of the impairment of maturation and of the targeting process, transfecting DUOX into nonthyroid cell lines has not led to the expression of a functional H2O2-generating system at the plasma membrane. For the first time, we investigated the H2O2-generating activity in the particulate fractions from DUOX2- and DUOX1-transfected HEK293 and Chinese hamster ovary cells. The particulate fractions of these cells stably or transiently transfected with human or porcine DUOX cDNA demonstrate a functional NADPH/Ca2+-dependent H2O2-generating activity. The immature Duox proteins had less activity than pig thyrocyte particulate fractions, and their activity depended on their primary structures. Human Duox2 seemed to be more active than human Duox1 but only half as active as its porcine counterpart. TPO co-transfection produced a slight increase in the enzymatic activity, whereas p22(phox), the 22-kDa subunit of the leukocyte NADPH oxidase, had no effect. In previous studies on the mechanism of H2O2 formation, it was shown that mature thyroid NADPH oxidase does not release O2*- but H2O2. Using a spin-trapping technique combined with electron paramagnetic resonance spectroscopy, we confirmed this result but also demonstrated that the partially glycosylated form of Duox2, located in the endoplasmic reticulum, generates superoxide in a calcium-dependent manner. These results suggest that post-translational modifications during the maturation process of Duox2 could be implicated in the mechanism of H2O2 formation by favoring intramolecular superoxide dismutation.
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Affiliation(s)
- Rabii Ameziane-El-Hassani
- Unité 486 INSERM, Université Paris 11, Faculté de Pharmacie, 5, rue J. B. Clément, 92296 Châtenay-Malabry Cedex, France
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20
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Sugawara M, Sugawara Y, Wen K, Giulivi C. Generation of oxygen free radicals in thyroid cells and inhibition of thyroid peroxidase. Exp Biol Med (Maywood) 2002; 227:141-6. [PMID: 11815678 DOI: 10.1177/153537020222700209] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
We examined whether superoxide (O(2)(-)) is produced as a precursor of hydrogen peroxide (H(2)O(2)) in cultured thyroid cells using the cytochrome c method and the electron paramagnetic resonance (EPR) method. No O(2)(-) or its related radicals was detected in thyroid cells under the physiological condition. The presence of quinone, 2,3-dimethoxy-l-naphthoquinone (DMNQ), or 2-methyl-1, 4-naphthoquinone (menadione), in the medium produced O(2)(-) and hydroxyl radicals (OH*); the amount of H(2)O(2) generation was also increased. Incubation of follicles with DMNQ or menadione inhibited iodine organification (a step of thyroid hormone formation) and its catalytic enzyme, thyroid peroxidase (TPO). This inhibition should be caused by reactive oxygen species because the two quinones, particularly DMNQ, exert their effect through the generation of reactive oxygen species. It is speculated that the site-specific inactivation of TPO might have occurred at the heme-linked histidine residue of the TPO molecule, a critical amino acid for enzyme activity because OH* (vicious free radicals) can be formed at the iron-linked amino acid. TPO mRNA level and electrophoretic mobility of TPO were not inhibited by quinones. Our study suggests that thyroid H(2)O(2) is produced by divalent reduction of oxygen without O(2)(-) generation. If thyroid cells happen to be exposed to significant amount of reactive oxygen species, TPO and subsequent thyroid hormone formation are inhibited.
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Affiliation(s)
- Masahiro Sugawara
- The Division of Endocrinology and Metabolism, West Los Angeles Veterans Affairs Medical Center and the Department of Medicine, University of California, Los Angeles, School of Medicine, Los Angeles, California 90073, USA.
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21
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Abstract
The thyroid concentrates iodide from the serum and oxidizes it at the apical membrane, attaching it to tyrosyl residues within thyroglobulin (Tg) to make diiodotyrosine and monoiodotyrosine. Major players in this process are Tg, thyroperoxidase (TPO), hydrogen peroxide, pendrin, and nicotinamide adenine dinucleotide phosphate (NADPH). Further action of TPO, hydrogen peroxide (H2O2), and iodinated Tg produce thyroxine (T4) and triiodothyronine (T3). Hormone-containing Tg is stored in the follicular lumen, then processed, most commonly by micropinocytosis. The lysosomal enzymes cathepsins B, L, and D are active in Tg proteolysis. Tg digestion leaves T4 and T3 intact, to be released from the cell, while the 3,5'-diiodotyrosine (DIT) and 3-iodotyrosine (MIT) are retained and deiodinated for recycling within the thyroid. Some areas of especially active recent research include: (1) the role of molecular chaperones in directing properly folded TPO and Tg to the apical membrane; (2) details of proteolytic pathways; (3) modulation of iodine metabolism, not only by thyrotropin (TSH) but by iodine supply and by feedback effects of Tg, glutathione, and inhibitory elements in the N-terminal region of Tg; and (4) details of Tg structure and iodotyrosyl coupling. Despite general agreement on the major steps in intrathyroidal iodine metabolism, new details of mechanisms are constantly being uncovered and are greatly improving understanding of the overall process.
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Affiliation(s)
- J T Dunn
- Department of Medicine, University of Virginia, Charlottesville, USA.
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22
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Abstract
Thyroglobulin (Tg) was subjected to metal-catalyzed oxidation, and the oxidative degradation was analyzed by SDS-polyacrylamide gel electrophoresis under reducing conditions. In contrast to no effect of hydrogen peroxide (H2O2) alone on the Tg degradation, the inclusion of Cu2+ (30 microM), in combination with 2 mM H2O2, caused a remarkable degradation of Tg, time- and concentration-dependent. The action of Cu2+ was not mimicked by Fe2+, suggesting that Tg may interact selectively with Cu2+. A similar degradation of Tg was also observed with Cu2+/ascorbate system, and the concentration of Cu2+ (5-10 microM), in combination with ascorbate, required for the effective degradation was smaller than that of Cu2+ (10-30 microM) in combination with H2O2. In support of involvement of H2O2 in the Cu2+/ascorbate action, catalase expressed a complete protection. However, hydroxyl radical scavengers such as dimethylsulfoxide or mannitol failed to prevent the oxidation of Tg whereas phenolic compounds, which can interact with Cu2+, diminished the oxidative degradation, presumably consistent with the mechanism for Cu2+-catalyzed oxidation of protein. Moreover, the amount of carbonyl groups in Tg was increased as the concentration (3-100 microM) of Cu2+ was enhanced, while the formation of acid-soluble peptides was not remarkable in the presence of Cu2+ up to 200 microM. In further studies, Tg pretreated with heat or trichloroacetic acid seemed to be somewhat resistant to Cu2+-catalyzed oxidation, implying a possible involvement of protein conformation in the susceptibility to the oxidation. Based on these observations, it is proposed that Tg could be degraded non-enzymatically by Cu2+-catalyzed oxidation.
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Affiliation(s)
- H J Lee
- College of Pharmacy, Chungnam National University, Taejon, Korea
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23
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Affiliation(s)
- J D Lambeth
- Dept of Biochemistry, Emory University Medical School, Atlanta, GA 30322, USA.
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24
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Baudry N, Lejeune PJ, Delom F, Vinet L, Carayon P, Mallet B. Role of multimerized porcine thyroglobulin in iodine storage. Biochem Biophys Res Commun 1998; 242:292-6. [PMID: 9446787 DOI: 10.1006/bbrc.1997.7952] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Thyroglobulin (Tg), the prothyroid hormone, is stored in the lumen of the thyroid follicles as soluble dimers and tetramers and insoluble multimers, Soluble Tg is well characterized with regards to structure and role, but insoluble Tg (i-Tg) is not. Here we show that i-Tg, multimerized through formation of disulfide and dityrosine bonds, has a higher iodine content than soluble Tg and no thyroid hormones. Furthermore, the size and the resistance of i-Tg to proteolytic enzymes implied a new mechanism by which thyrocytes may degrade this form of Tg. Using peroxidase and H2O2 generating system, we found that about 80% of i-Tg was degraded and 24% of its iodine content was released. Our data point to a role for i-Tg in iodine storage and the involvement of TPO in i-Tg degradation and iodide release.
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Affiliation(s)
- N Baudry
- Faculté de Médecine, Unité 38 INSERM, Marseille, France
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25
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Iwase K, Kato K, Ohtani S, Tsujimura T, Hanai T, Inagaki A, Jimbo S, Kobayashi N, Yamamoto H, Nagasaka A, Miura K. The Relation between Superoxide Dismutase in Cancer Tissue and Clinico-pathological Features in Breast Cancer. Breast Cancer 1997; 4:155-160. [PMID: 11091590 DOI: 10.1007/bf02967069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The localization of Cu/Zn- and Mn-superoxide dismutase (SOD) in breast cancer tissue (12 papillotubular carcinomas, 21 solid-tubular carcinomas, 16 scirrhous carcinomas, 1 medullary carcinoma, 1 secreting carcinoma, 1 lobular carcinoma, 1 Paget's disease) was investigated via an immunohistochemical technique using antihuman Cu/Zn- and Mn-SOD antibodies in 10%formalin fixed-paraffin embedded thin sections. Both SODs stained strongly in the normal breast gland, but not clearly in many cancer tissues. Furthermore, Cu/Zn-SOD stained more strongly in well differentiated tubular carcinomas than in poorly differentiated tubular carcinomas. It tended to stain less in tumors which recurred or had a poor outcome, and in tumors with a diploid pattern on DNA flow cytometry. Mn-SOD staining was similar to that of Cu/Zn-SOD, but no significant differences among subgroups was found, since the incidence of positively staining tumors was too small in all groups. The intensity of SOD staining seems to change in relation to cell proliferation and differentiation in breast carcinoma, and may be a prognostic indicator, since SOD decreased in poorly differentiated carcinoma and in tumors which developed distant metastasis. Thus, the localization of SOD in breast cancer tissue can provide useful information for cancer treatment.
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Affiliation(s)
- K Iwase
- Departments of Surgery, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsugake-cho, Toyoake 470-11, Japan
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26
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Nishida S, Nakano T, Kimoto S, Kusunoki T, Suzuki K, Taniguchi N, Murata K, Tomura TT. Induction of manganese superoxide dismutase by thyroid stimulating hormone in rat thyroid cells. FEBS Lett 1997; 416:69-71. [PMID: 9369235 DOI: 10.1016/s0014-5793(97)01171-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Alterations in the superoxide dismutase (SOD) content of thyroid tissues occurring in association with thyroid dysfunction have been reported. In this study, the Mn-SOD content was found to increase in thyroid tissues of rats administered thyroid stimulating hormone (TSH) and in thyrocytes cultured in medium supplemented with TSH. Furthermore, in the thyroid glands of rats whose serum TSH level was elevated by inhibiting the synthesis of T3 and T4 by 6-methyl-2-thiouracil, the Mn-SOD increased as the TSH concentration increased. In the cultured thyrocytes, the increase in Mn-SOD induced by TSH was inhibited by the C-kinase inhibitor H7. These findings suggest the induction of Mn-SOD by TSH in thyroid cells and point to a role of C-kinase in this process, thereby indicating that a close relationship exists between the serum TSH level and the change in Mn-SOD content in thyrocytes with thyroid dysfunction.
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Affiliation(s)
- S Nishida
- Department of Biochemistry and Oncology, Kinki University School of Medicine, Osakasayama, Osaka, Japan.
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27
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Gorin Y, Ohayon R, Carvalho DP, Dème D, Leseney AM, Haye B, Kaniewski J, Pommier J, Virion A, Dupuy C. Solubilization and characterization of a thyroid Ca(2+)-dependent and NADPH-dependent K3Fe(CN)6 reductase. Relationship with the NADPH-dependent H2O2-generating system. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 240:807-14. [PMID: 8856087 DOI: 10.1111/j.1432-1033.1996.0807h.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The thyroid plasma membrane contains a Ca(2+)-regulated NADPH-dependent H2O2-generating system which provides H2O2 for the thyroid-peroxidase-catalyzed biosynthesis of thyroid hormones. The molecular nature of the membrane-associated electron transport chain that generates H2O2 in the thyroid is unknown, but recent observations indicate that a flavoprotein containing a FAD prosthetic group is involved. Solubilization was reinvestigated using 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (Chaps), Triton X-100, and high salt concentrations. Chaps eliminated about 30% of the proteins, which included a ferricyanide reductase, without affecting the H2O2-generating system. Similarly, Triton X-100 alone did not extract the NADPH oxidase. An NADPH-oxidase activity, which was measured in the presence of the artificial electron acceptor potassium ferricyanide, was solubilized by increasing the ionic strength to 2 M KCl. This NADPH-ferricyanide reductase activity was shown to belong to the H2O2-generating system, although it did not produce H2O2. It was still Ca2+ dependent and H2O2 production was restored by decreasing the ionic strength by overnight dialysis. No H2O2 production activity was detected after sucrose density gradient centrifugation of the dialyzed solubilized enzyme, but a well-defined peak of NADPH oxidation activity with a sedimentation coefficient of 3.71 S was found in the presence of K3Fe(CN)6. These results suggest that some unknown component(s) (phospholipid or protein) is removed during sucrose density gradient centrifugation. Finally, thyrotropin, which induces NADPH oxidase and regulates H2O2 production in porcine thyrocytes in primary culture, also induced the NADPH-K3Fe(CN)6 reductase activity associated with the H2O2-generating system. Thus, this enzyme seems to be another marker of thyroid differentiation.
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Affiliation(s)
- Y Gorin
- Unité 96 INSERM, Le Kremlin-Bicêtre, France
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28
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Goeptar AR, Scheerens H, Vermeulen NP. Oxygen and xenobiotic reductase activities of cytochrome P450. Crit Rev Toxicol 1995; 25:25-65. [PMID: 7734059 DOI: 10.3109/10408449509089886] [Citation(s) in RCA: 171] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The oxygen reductase and xenobiotic reductase activities of cytochrome P450 (P450) are reviewed. During the oxygen reductase activity of P450, molecular oxygen is reduced to superoxide anion radicals (O2-.) most likely by autooxidation of a P450 ferric-dioxyanion complex. The formation of reactive oxygen species (O2-., hydrogen peroxide, and, notably, hydroxyl free radicals) presents a potential toxication pathway, particularly when effective means of detoxication are lacking. Under anaerobic conditions, P450 may also be involved in the reduction of xenobiotics. During the xenobiotic reductase activity of P450, xenobiotics are reduced by the ferrous xenobiotic complex. After xenobiotic reduction by P450, xenobiotic free radicals are formed that are often capable of reacting directly with tissue macromolecules. Unfortunately, the compounds that are reductively activated by P450 have little structural similarity. The precise molecular mechanism underlying the xenobiotic reductase activity of P450 is, therefore, not yet fully understood. Moreover, description of the molecular mechanisms of xenobiotic and oxygen reduction reactions by P450 is limited by the lack of knowledge of the three-dimensional (3D) structure of the mammalian P450 proteins.
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Affiliation(s)
- A R Goeptar
- Leiden/Amsterdam Center for Drug Research, Vrije Universiteit, The Netherlands
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29
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Cross AR, Jones OT. Enzymic mechanisms of superoxide production. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1057:281-98. [PMID: 1851438 DOI: 10.1016/s0005-2728(05)80140-9] [Citation(s) in RCA: 361] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- A R Cross
- Department of Biochemistry, School of Medical Sciences, University of Bristol, U.K
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30
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Dupuy C, Virion A, Ohayon R, Kaniewski J, Dème D, Pommier J. Mechanism of hydrogen peroxide formation catalyzed by NADPH oxidase in thyroid plasma membrane. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(19)67857-9] [Citation(s) in RCA: 95] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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31
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Dupuy C, Kaniewski J, Dème D, Pommier J, Virion A. NADPH-dependent H2O2 generation catalyzed by thyroid plasma membranes. Studies with electron scavengers. EUROPEAN JOURNAL OF BIOCHEMISTRY 1989; 185:597-603. [PMID: 2556271 DOI: 10.1111/j.1432-1033.1989.tb15155.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Hog thyroid plasma membrane preparations containing a Ca2+-regulated NADPH-dependent H2O2-generating system were studied. The Ca2+-dependent reductase activities of ferricytochrome c, 2,6-dichloroindophenol, nitroblue tetrazolium, and potassium ferricyanide were tested and the effect of these scavengers on H2O2 formation, NADPH oxidation and O2 consumption were measured, with the following results. 1. Thyroid plasma membrane Ca2+-independent cytochrome c reduction was not catalyzed by the NADPH-dependent H2O2-generating system. This activity was superoxide-dismutase-insensitive. 2. Of the three other electron scavengers tested, only K3Fe(CN)6 was clearly, but partially reduced in a Ca2+-dependent manner. 3. Though the NADPH-dependent reduction of nitroblue tetrazolium was very low and superoxide-dismutase-insensitive, nitroblue tetrazolium inhibited O2 consumption, H2O2 formation and NADPH oxidation, indicating that nitroblue tetrazolium inhibits the H2O2-generating system. We conclude that the thyroid plasma membrane H2O2-generating system does not or liberate O2- and that Ca2+ controls the first step (NADPH oxidation) of the H2O2-generating system.
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Affiliation(s)
- C Dupuy
- Institut National de la Santé et de la Recherche Médicale, Unité de Recherches sur la Glande Thyroide et la Régulation Hormonale, Le-Kremlin-Bicêtre, France
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