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Condeles AL, Toledo Junior JC. The Labile Iron Pool Reacts Rapidly and Catalytically with Peroxynitrite. Biomolecules 2021; 11:1331. [PMID: 34572543 PMCID: PMC8466499 DOI: 10.3390/biom11091331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 12/23/2022] Open
Abstract
While investigating peroxynitrite-dependent oxidation in murine RAW 264.7 macrophage cells, we observed that removal of the Labile Iron Pool (LIP) by chelation increases the intracellular oxidation of the fluorescent indicator H2DCF, so we concluded that the LIP reacts with peroxynitrite and decreases the yield of peroxynitrite-derived oxidants. This was a paradigm-shifting finding in LIP biochemistry and raised many questions. In this follow-up study, we address fundamental properties of the interaction between the LIP and peroxynitrite by using the same cellular model and fluorescence methodology. We have identified that the reaction between the LIP and peroxynitrite has catalytic characteristics, and we have estimated that the rate constant of the reaction is in the range of 106 to 107 M-1s-1. Together, these observations suggest that the LIP represents a constitutive peroxynitrite reductase system in RAW 264.7 cells.
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Affiliation(s)
| | - José Carlos Toledo Junior
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil;
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Zhang L, Zhang H, Wang L, Fan Y, Zhang C, Li X, Han D, Ji C. Protective Effects of Emodin on Lung Injuries in Rat Models of Liver Fibrosis. Open Life Sci 2019; 14:611-618. [PMID: 33817199 PMCID: PMC7874798 DOI: 10.1515/biol-2019-0069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 07/03/2019] [Indexed: 11/16/2022] Open
Abstract
Objective The aim of this study is to investigate the protective effects of emodin (EMD) on the lung injuries in the rat models of liver fibrosis. Methods Liver fibrosis was established in rats and the effect of intervention using EMD treatment was determined. Liver and lung weight coefficients were measured and lung content of TNF-α (tumor necrosis factor α), MDA (malondialdehyde), NO (nitric oxide), and ONOO- (peroxynitrite) were determined. Finally, histopathological changes were evaluated. Results Compared with the normal control group, the lung weight coefficient was significantly increased in the fibrosis model group. Moreover, pulmonary edema and inflammatory responses were observed. Levels of TNF-α, MDA, NO, and ONOO- in the lung homogenate were significantly increased in the fibrosis model group. After EMD treatment, the lung weight coefficients were significantly reduced. Moreover, pathological changes in the lung tissue were dramatically alleviated. Levels of TNF-α, MDA, NO, and ONOO- were significantly decreased. Conclusion EMD exhibits protective effects against lung injuries in a rat model of liver fibrosis.
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Affiliation(s)
- Lili Zhang
- Department of Pathophysiology, Changzhi Medical College, No. 161, Jiefang East Street, Changzhi, Shanxi 046000, China
| | - Huiying Zhang
- Department of Pathophysiology, Changzhi Medical College, No. 161, Jiefang East Street, Changzhi, Shanxi 046000, China
| | - Limin Wang
- Function Laboratory, Changzhi Medical College, Changzhi, Shanxi 046000, China
| | - Yimin Fan
- Function Laboratory, Changzhi Medical College, Changzhi, Shanxi 046000, China
| | - Cuiying Zhang
- Department of Pathophysiology, Changzhi Medical College, No. 161, Jiefang East Street, Changzhi, Shanxi 046000, China
| | - Xujiong Li
- Department of Pathophysiology, Changzhi Medical College, No. 161, Jiefang East Street, Changzhi, Shanxi 046000, China
| | - Dewu Han
- Institute of Liver Diseases, Shanxi Medical University, Taiyuan, Shanxi 030001, China
| | - Cheng Ji
- Research Center for Liver Diseases, Keck School of Medicine, University of Southern California, Loa Angeles, CA 90089, USA
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Damasceno FC, Condeles AL, Lopes AKB, Facci RR, Linares E, Truzzi DR, Augusto O, Toledo JC. The labile iron pool attenuates peroxynitrite-dependent damage and can no longer be considered solely a pro-oxidative cellular iron source. J Biol Chem 2018; 293:8530-8542. [PMID: 29661935 DOI: 10.1074/jbc.ra117.000883] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 04/12/2018] [Indexed: 01/01/2023] Open
Abstract
The ubiquitous cellular labile iron pool (LIP) is often associated with the production of the highly reactive hydroxyl radical, which forms through a redox reaction with hydrogen peroxide. Peroxynitrite is a biologically relevant peroxide produced by the recombination of nitric oxide and superoxide. It is a strong oxidant that may be involved in multiple pathological conditions, but whether and how it interacts with the LIP are unclear. Here, using fluorescence spectroscopy, we investigated the interaction between the LIP and peroxynitrite by monitoring peroxynitrite-dependent accumulation of nitrosated and oxidized fluorescent intracellular indicators. We found that, in murine macrophages, removal of the LIP with membrane-permeable iron chelators sustainably accelerates the peroxynitrite-dependent oxidation and nitrosation of these indicators. These observations could not be reproduced in cell-free assays, indicating that the chelator-enhancing effect on peroxynitrite-dependent modifications of the indicators depended on cell constituents, presumably including LIP, that react with these chelators. Moreover, neither free nor ferrous-complexed chelators stimulated intracellular or extracellular oxidative and nitrosative chemistries. On the basis of these results, LIP appears to be a relevant and competitive cellular target of peroxynitrite or its derived oxidants, and thereby it reduces oxidative processes, an observation that may change the conventional notion that the LIP is simply a cellular source of pro-oxidant iron.
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Affiliation(s)
- Fernando Cruvinel Damasceno
- From the Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, CEP 14040-901 and
| | - André Luis Condeles
- From the Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, CEP 14040-901 and
| | - Angélica Kodama Bueno Lopes
- From the Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, CEP 14040-901 and
| | - Rômulo Rodrigues Facci
- From the Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, CEP 14040-901 and
| | - Edlaine Linares
- the Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, CEP 05508-000, Brazil
| | - Daniela Ramos Truzzi
- the Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, CEP 05508-000, Brazil
| | - Ohara Augusto
- the Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, CEP 05508-000, Brazil
| | - José Carlos Toledo
- From the Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, CEP 14040-901 and
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Brienza M, Duwig C, Pérez S, Chiron S. 4-nitroso-sulfamethoxazole generation in soil under denitrifying conditions: Field observations versus laboratory results. JOURNAL OF HAZARDOUS MATERIALS 2017; 334:185-192. [PMID: 28412628 DOI: 10.1016/j.jhazmat.2017.04.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 04/04/2017] [Accepted: 04/05/2017] [Indexed: 06/07/2023]
Abstract
The formation of 4-nitroso-sulfamethoxazole and 4-nitro-SMX, two transformation products (TPs) of sulfamethoxazole (SMX) was investigated under batch soil slurry experiments and in a field study. Due to their low occurrence levels (ng/L) in environmental waters, a suitable analytical method based on liquid chromatography - high resolution - mass spectrometry was developed. Consequently, field observations revealed, for the first time, the occurrence of 4-nitroso-SMX in groundwater at concentrations as high as 18ng/L.Nitric oxide (NO) steady-state concentrations were determined in soil slurry experiments because this reactive specie accounted for the formation of 4-nitroso-SMX and 4-nitro-SMX. Measurements revealed that environmental SMX concentrations (0.2-2μg/L) at neutral pH induced the accumulation of nitric oxide. Under acidic conditions (pH<6), nitrous acid (HONO) was the major source of nitric oxide while under neutral/basic conditions nitric oxide release was related to the inhibition of denitrification processes. Under laboratory experiments, SMX nitration reaction appeared to be an irreversible transformation pathway, while 4-nitroso-SMX was slowly transformed over time. The occurrence of 4-nitroso-SMX conditions was therefore unexpected in the field study but could be due to its continuous input from soil and/or its relative persistence under anoxic conditions. A mechanism for 4-nitroso-SMX formation was proposed involving a nitrosative desamination pathway through a phenyl radical.
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Affiliation(s)
- Monica Brienza
- UMR HydroSciences 5569, IRD, Montpellier University, 15 Avenue Ch. Flahault, 34093 Montpellier Cedex 5, France
| | - Céline Duwig
- UMR LTHE 5564, IRD, Grenoble University, 70, rue de la physique - Domaine Universitaire, 38041 Grenoble Cedex 9, France
| | - Sandra Pérez
- Water and Soil Quality Research Group, IDAEA-CSIC, c/Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Serge Chiron
- UMR HydroSciences 5569, IRD, Montpellier University, 15 Avenue Ch. Flahault, 34093 Montpellier Cedex 5, France.
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Glory A, Averill-Bates DA. The antioxidant transcription factor Nrf2 contributes to the protective effect of mild thermotolerance (40°C) against heat shock-induced apoptosis. Free Radic Biol Med 2016; 99:485-497. [PMID: 27591796 DOI: 10.1016/j.freeradbiomed.2016.08.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 08/07/2016] [Accepted: 08/31/2016] [Indexed: 10/21/2022]
Abstract
The exposure of cells to low doses of stress induces adaptive survival responses that protect cells against subsequent exposure to toxic stress. The ability of cells to resist subsequent toxic stress following exposure to low dose heat stress at 40°C is known as mild thermotolerance. Mild thermotolerance involves increased expression of heat shock proteins and antioxidants, but the initiating factors in this response are not understood. This study aims to understand the role of the Nrf2 antioxidant pathway in acquisition of mild thermotolerance at 40°C, and secondly, whether the Nrf2 pathway could be involved in the protective effect of thermotolerance against heat-shock (42°C)-induced apoptosis. During cell preconditioning at 40°C, protein expression of the Nrf2 transcription factor increased after 15-60min. In addition, levels of the Nrf2 targets MnSOD, catalase, heme oxygenase-1, glutamate cysteine ligase and Hsp70 increased at 40°C. Levels of these Nrf2 targets were enhanced by Nrf2 activator oltipraz and decreased by shRNA targeting Nrf2. Levels of pro-oxidants increased after 30-60min at 40°C. Pro-oxidant levels were decreased by oltipraz and increased by knockdown of Nrf2. Increased Nrf2 expression and catalase activity at 40°C were inhibited by the antioxidant PEG-catalase and by p53 inhibitor pifithrin-α. These results suggest that mild thermotolerance (40°C) increases cellular pro-oxidant levels, which in turn activate Nrf2 and its target genes. Moreover, Nrf2 contributes to the protective effect of thermotolerance against heat-shock (42°C)-induced apoptosis, because Nrf2 activation by oltipraz enhanced thermotolerance, whereas Nrf2 knockdown partly reversed thermotolerance. Improved knowledge about the different protective mechanisms that mild thermotolerance can activate is crucial for the potential use of this adaptive survival response to treat stress-related diseases.
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Affiliation(s)
- Audrey Glory
- Département des Sciences Biologiques (TOXEN), Université du Québec à Montréal, CP 8888, Succursale Center-Ville Montréal, Montréal, Québec, Canada H3C 3P8
| | - Diana A Averill-Bates
- Département des Sciences Biologiques (TOXEN), Université du Québec à Montréal, CP 8888, Succursale Center-Ville Montréal, Montréal, Québec, Canada H3C 3P8.
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Pinheiro LC, Amaral JH, Ferreira GC, Portella RL, Ceron CS, Montenegro MF, Toledo JC, Tanus-Santos JE. Gastric S-nitrosothiol formation drives the antihypertensive effects of oral sodium nitrite and nitrate in a rat model of renovascular hypertension. Free Radic Biol Med 2015; 87:252-62. [PMID: 26159506 DOI: 10.1016/j.freeradbiomed.2015.06.038] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 06/11/2015] [Accepted: 06/26/2015] [Indexed: 01/01/2023]
Abstract
Many effects of nitrite and nitrate are attributed to increased circulating concentrations of nitrite, ultimately converted into nitric oxide (NO(•)) in the circulation or in tissues by mechanisms associated with nitrite reductase activity. However, nitrite generates NO(•) , nitrous anhydride, and other nitrosating species at low pH, and these reactions promote S-nitrosothiol formation when nitrites are in the stomach. We hypothesized that the antihypertensive effects of orally administered nitrite or nitrate involve the formation of S-nitrosothiols, and that those effects depend on gastric pH. The chronic effects of oral nitrite or nitrate were studied in two-kidney, one-clip (2K1C) hypertensive rats treated with omeprazole (or vehicle). Oral nitrite lowered blood pressure and increased plasma S-nitrosothiol concentrations independently of circulating nitrite levels. Increasing gastric pH with omeprazole did not affect the increases in plasma nitrite and nitrate levels found after treatment with nitrite. However, treatment with omeprazole severely attenuated the increases in plasma S-nitrosothiol concentrations and completely blunted the antihypertensive effects of nitrite. Confirming these findings, very similar results were found with oral nitrate. To further confirm the role of gastric S-nitrosothiol formation, we studied the effects of oral nitrite in hypertensive rats treated with the glutathione synthase inhibitor buthionine sulfoximine (BSO) to induce partial thiol depletion. BSO treatment attenuated the increases in S-nitrosothiol concentrations and antihypertensive effects of oral nitrite. These data show that gastric S-nitrosothiol formation drives the antihypertensive effects of oral nitrite or nitrate and has major implications, particularly to patients taking proton pump inhibitors.
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Affiliation(s)
- Lucas C Pinheiro
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Jefferson H Amaral
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Graziele C Ferreira
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Rafael L Portella
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Carla S Ceron
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Marcelo F Montenegro
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil
| | - Jose Carlos Toledo
- Department of Chemistry, Faculty of Philosophy and Sciences of Ribeirao Preto, University of Sao Paulo, 14040-901, Ribeirao Preto, SP, Brazil
| | - Jose E Tanus-Santos
- Department of Pharmacology, Ribeirao Preto Medical School, University of Sao Paulo, Av. Bandeirantes, 3900, 14049-900, Ribeirao Preto, SP, Brazil.
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