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Flohé L. Looking Back at the Early Stages of Redox Biology. Antioxidants (Basel) 2020; 9:E1254. [PMID: 33317108 PMCID: PMC7763103 DOI: 10.3390/antiox9121254] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 11/12/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
The beginnings of redox biology are recalled with special emphasis on formation, metabolism and function of reactive oxygen and nitrogen species in mammalian systems. The review covers the early history of heme peroxidases and the metabolism of hydrogen peroxide, the discovery of selenium as integral part of glutathione peroxidases, which expanded the scope of the field to other hydroperoxides including lipid hydroperoxides, the discovery of superoxide dismutases and superoxide radicals in biological systems and their role in host defense, tissue damage, metabolic regulation and signaling, the identification of the endothelial-derived relaxing factor as the nitrogen monoxide radical (more commonly named nitric oxide) and its physiological and pathological implications. The article highlights the perception of hydrogen peroxide and other hydroperoxides as signaling molecules, which marks the beginning of the flourishing fields of redox regulation and redox signaling. Final comments describe the development of the redox language. In the 18th and 19th century, it was highly individualized and hard to translate into modern terminology. In the 20th century, the redox language co-developed with the chemical terminology and became clearer. More recently, the introduction and inflationary use of poorly defined terms has unfortunately impaired the understanding of redox events in biological systems.
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Affiliation(s)
- Leopold Flohé
- Dipartimento di Medicina Molecolare, Università degli Studi di Padova, v.le G. Colombo 3, 35121 Padova, Italy;
- Departamento de Bioquímica, Universidad de la República, Avda. General Flores 2125, 11800 Montevideo, Uruguay
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52
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Alshaabi H, Shannon N, Gravelle R, Milczarek S, Messier T, Cunniff B. Miro1-mediated mitochondrial positioning supports subcellular redox status. Redox Biol 2020; 38:101818. [PMID: 33341544 PMCID: PMC7753203 DOI: 10.1016/j.redox.2020.101818] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/06/2020] [Accepted: 11/23/2020] [Indexed: 01/09/2023] Open
Abstract
Mitochondria are strategically trafficked throughout the cell by the action of microtubule motors, the actin cytoskeleton and adapter proteins. The intracellular positioning of mitochondria supports subcellular levels of ATP, Ca2+ and reactive oxygen species (ROS, i.e. hydrogen peroxide, H2O2). Previous work from our group showed that deletion of the mitochondrial adapter protein Miro1 leads to perinuclear clustering of mitochondria, leaving the cell periphery devoid of mitochondria which compromises peripheral energy status. Herein, we report that deletion of Miro1 significantly restricts subcellular H2O2 levels to the perinuclear space which directly affects intracellular responses to elevated mitochondrial ROS. Using the genetically encoded H2O2-responsive fluorescent biosensor HyPer7, we show that the highest levels of subcellular H2O2 map to sites of increased mitochondrial density. Deletion of Miro1 or disruption of microtubule dynamics with Taxol significantly reduces peripheral H2O2 levels. Following inhibition of mitochondrial complex 1 with rotenone we observe elevated spikes of H2O2 in the cell periphery and complementary oxidation of mitochondrial peroxiredoxin 3 (PRX3) and cytosolic peroxiredoxin 2 (PRX2). Conversely, in cells lacking Miro1, rotenone did not increase peripheral H2O2 or PRX2 oxidation but rather lead to increased nuclear H2O2 and an elevated DNA-damage response. Lastly, local levels of HyPer7 oxidation correlate with the size and abundance of focal adhesions (FAs) in MEFs and cells lacking Miro1 have significantly smaller focal adhesions and reduced phosphorylation levels of vinculin and p130Cas compared to Miro1+/+ MEFs. Together, we present evidence that the intracellular distribution of mitochondria influences subcellular H2O2 levels and local cellular responses dependent on mitochondrial ROS.
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Affiliation(s)
- Haya Alshaabi
- Department of Pathology and Laboratory Medicine, University of Vermont Cancer Center, Larner College of Medicine, Burlington, VT 05405, USA
| | - Nathaniel Shannon
- Department of Pathology and Laboratory Medicine, University of Vermont Cancer Center, Larner College of Medicine, Burlington, VT 05405, USA
| | - Randi Gravelle
- Department of Pathology and Laboratory Medicine, University of Vermont Cancer Center, Larner College of Medicine, Burlington, VT 05405, USA
| | - Stephanie Milczarek
- Department of Pathology and Laboratory Medicine, University of Vermont Cancer Center, Larner College of Medicine, Burlington, VT 05405, USA
| | - Terri Messier
- Department of Pathology and Laboratory Medicine, University of Vermont Cancer Center, Larner College of Medicine, Burlington, VT 05405, USA
| | - Brian Cunniff
- Department of Pathology and Laboratory Medicine, University of Vermont Cancer Center, Larner College of Medicine, Burlington, VT 05405, USA.
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53
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Oxidative Stress in Cytokine-Induced Dysfunction of the Pancreatic Beta Cell: Known Knowns and Known Unknowns. Metabolites 2020; 10:metabo10120480. [PMID: 33255484 PMCID: PMC7759861 DOI: 10.3390/metabo10120480] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/18/2020] [Accepted: 11/21/2020] [Indexed: 12/12/2022] Open
Abstract
Compelling evidence from earlier studies suggests that the pancreatic beta cell is inherently weak in its antioxidant defense mechanisms to face the burden of protecting itself against the increased intracellular oxidative stress following exposure to proinflammatory cytokines. Recent evidence implicates novel roles for nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (Noxs) as contributors to the excessive intracellular oxidative stress and damage under metabolic stress conditions. This review highlights the existing evidence on the regulatory roles of at least three forms of Noxs, namely Nox1, Nox2, and Nox4, in the cascade of events leading to islet beta cell dysfunction, specifically under the duress of chronic exposure to cytokines. Potential crosstalk between key signaling pathways (e.g., inducible nitric oxide synthase [iNOS] and Noxs) in the generation and propagation of reactive molecules and metabolites leading to mitochondrial damage and cell apoptosis is discussed. Available data accrued in investigations involving small-molecule inhibitors and antioxidant protein expression methods as tools toward the prevention of cytokine-induced oxidative damage are reviewed. Lastly, current knowledge gaps in this field, and possible avenues for future research are highlighted.
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54
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Warpsinski G, Smith MJ, Srivastava S, Keeley TP, Siow RCM, Fraser PA, Mann GE. Nrf2-regulated redox signaling in brain endothelial cells adapted to physiological oxygen levels: Consequences for sulforaphane mediated protection against hypoxia-reoxygenation. Redox Biol 2020; 37:101708. [PMID: 32949969 PMCID: PMC7502377 DOI: 10.1016/j.redox.2020.101708] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/21/2020] [Accepted: 08/27/2020] [Indexed: 02/06/2023] Open
Abstract
Ischemic stroke is associated with a surge in reactive oxygen species generation during reperfusion. The narrow therapeutic window for the delivery of intravenous thrombolysis and endovascular thrombectomy limits therapeutic options for patients. Thus, understanding the mechanisms regulating neurovascular redox defenses are key for improved clinical translation. Our previous studies in a rodent model of ischemic stroke established that activation of Nrf2 defense enzymes by pretreatment with sulforaphane (SFN) affords protection against neurovascular and neurological deficits. We here further investigate SFN mediated protection in mouse brain microvascular endothelial cells (bEnd.3) adapted long-term (5 days) to hyperoxic (18 kPa) and normoxic (5 kPa) O2 levels. Using an O2-sensitive phosphorescent nanoparticle probe, we measured an intracellular O2 level of 3.4 ± 0.1 kPa in bEnd 3 cells cultured under 5 kPa O2. Induction of HO-1 and GCLM by SFN (2.5 μM) was significantly attenuated in cells adapted to 5 kPa O2, despite nuclear accumulation of Nrf2. To simulate ischemic stroke, bEnd.3 cells were adapted to 18 or 5 kPa O2 and subjected to hypoxia (1 kPa O2, 1 h) and reoxygenation. In cells adapted to 18 kPa O2, reoxygenation induced free radical generation was abrogated by PEG-SOD and significantly attenuated by pretreatment with SFN (2.5 μM). Silencing Nrf2 transcription abrogated HO-1 and NQO1 induction and led to a significant increase in reoxygenation induced free radical generation. Notably, reoxygenation induced oxidative stress, assayed using the luminescence probe L-012 and fluorescence probes MitoSOX™ Red and FeRhoNox™-1, was diminished in cells cultured under 5 kPa O2, indicating an altered redox phenotype in brain microvascular cells adapted to physiological normoxia. As redox and other intracellular signaling pathways are critically affected by O2, the development of antioxidant therapies targeting the Keap1-Nrf2 defense pathway in treatment of ischemia-reperfusion injury in stroke, coronary and renal disease will require in vitro studies conducted under well-defined O2 levels. Physiological normoxia alters the redox phenotype of murine microvascular brain endothelial cells. Intracellular GSH levels are lower in bEnd.3 cells adapted to 5 kPa versus 18 kPa O2. Nrf2 activated HO-1 and GCLM expression is attenuated under physiological normoxia. Sulforaphane protects against reoxygenation induced reactive oxygen species generation via Nrf2.
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Affiliation(s)
- Gabriela Warpsinski
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Matthew J Smith
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Salil Srivastava
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Thomas P Keeley
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Richard C M Siow
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Paul A Fraser
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Giovanni E Mann
- King's British Heart Foundation Centre for Research Excellence, School of Cardiovascular Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK.
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Pavlov TS, Palygin O, Isaeva E, Levchenko V, Khedr S, Blass G, Ilatovskaya DV, Cowley AW, Staruschenko A. NOX4-dependent regulation of ENaC in hypertension and diabetic kidney disease. FASEB J 2020; 34:13396-13408. [PMID: 32799394 DOI: 10.1096/fj.202000966rr] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 12/11/2022]
Abstract
NADPH oxidase 4 (NOX4) is the most abundant NOX isoform in the kidney; however, its importance for renal function has only recently emerged. The NOX4-dependent pathway regulates many factors essential for proper sodium handling in the distal nephron. However, the functional significance of this pathway in the control of sodium reabsorption during the initiation of chronic kidney disease is not established. The goal of this study was to test Nox4-dependent ENaC regulation in two models: SS hypertension and STZ-induced type 1 diabetes. First, we showed that genetic ablation of Nox4 in Dahl salt-sensitive (SS) rat attenuated a high-salt (HS)-induced increase in epithelial Na+ channel (ENaC) activity in the cortical collecting duct. We also found that H2 O2 upregulated ENaC activity, and H2 O2 production was reduced in both the renal cortex and medulla in SSNox4-/- rats fed an HS diet. Second, in the streptozotocin model of hyperglycemia-induced renal injury ENaC activity in hyperglycemic animals was elevated in SS but not SSNox4-/- rats. NaCl cotransporter (NCC) expression was increased compared to healthy controls, while expression values between SS and SSNox4-/- groups were similar. These data emphasize a critical contribution of the NOX4-mediated pathway in maladaptive upregulation of ENaC-mediated sodium reabsorption in the distal nephron in the conditions of HS- and hyperglycemia-induced kidney injury.
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Affiliation(s)
- Tengis S Pavlov
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Division of Hypertension and Vascular Research, Henry Ford Health System, Detroit, MI, USA
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Elena Isaeva
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Sherif Khedr
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Physiology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Gregory Blass
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA.,Clement J. Zablocki VA Medical Center, Milwaukee, WI, USA
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