1
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Altun HY, Secilmis M, Yang F, Akgul Caglar T, Vatandaslar E, Toy MF, Vilain S, Mann GE, Öztürk G, Eroglu E. Visualizing hydrogen peroxide and nitric oxide dynamics in endothelial cells using multispectral imaging under controlled oxygen conditions. Free Radic Biol Med 2024; 221:89-97. [PMID: 38735541 DOI: 10.1016/j.freeradbiomed.2024.05.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 04/04/2024] [Accepted: 05/10/2024] [Indexed: 05/14/2024]
Abstract
The complex interplay between hydrogen peroxide (H2O2) and nitric oxide (NO) in endothelial cells presents challenges due to technical limitations in simultaneous measurement, hindering the elucidation of their direct relationship. Previous studies have yielded conflicting findings regarding the impact of H2O2 on NO production. To address this problem, we employed genetically encoded biosensors, HyPer7 for H2O2 and geNOps for NO, allowing simultaneous imaging in single endothelial cells. Optimization strategies were implemented to enhance biosensor performance, including camera binning, temperature regulation, and environmental adjustments to mimic physiological normoxia. Our results demonstrate that under ambient oxygen conditions, H2O2 exhibited no significant influence on NO production. Subsequent exploration under physiological normoxia (5 kPa O2) revealed distinct oxidative stress levels characterized by reduced basal HyPer7 signals, enhanced H2O2 scavenging kinetics, and altered responses to pharmacological treatment. Investigation of the relationship between H2O2 and NO under varying oxygen conditions revealed a lack of NO response to H2O2 under hyperoxia (18 kPa O2) but a modest NO response under physiological normoxia (5 kPa O2). Importantly, the NO response was attenuated by l-NAME, suggesting activation of eNOS by endogenous H2O2 generation upon auranofin treatment. Our study highlights the intricate interplay between H2O2 and NO within the endothelial EA.hy926 cell line, emphasizing the necessity for additional research within physiological contexts due to differential response observed under physiological normoxia (5 kPa O2). This further investigation is essential for a comprehensive understanding of the H2O2 and NO signaling considering the physiological effects of ambient O2 levels involved.
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Affiliation(s)
- Hamza Yusuf Altun
- Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, 34810, Istanbul, Turkey; Molecular Biology, Genetics, and Bioengineering Program, Sabanci University, 34956, Istanbul, Turkey
| | - Melike Secilmis
- Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, 34810, Istanbul, Turkey; Molecular Biology, Genetics, and Bioengineering Program, Sabanci University, 34956, Istanbul, Turkey
| | - Fan Yang
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Tuba Akgul Caglar
- Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, 34810, Istanbul, Turkey; Molecular Biology, Genetics, and Bioengineering Program, Sabanci University, 34956, Istanbul, Turkey
| | - Emre Vatandaslar
- Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, 34810, Istanbul, Turkey
| | - Muhammed Fatih Toy
- School of Engineering and Natural Science, Istanbul Medipol University, 34810, Istanbul, Turkey
| | - Sven Vilain
- Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, 34810, Istanbul, Turkey.
| | - Giovanni E Mann
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK.
| | - Gürkan Öztürk
- Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, 34810, Istanbul, Turkey; Physiology Department, School of Medicine, Bolu Abant Izzet Baysal University (BAIBU), 14200, Bolu, Türkiye.
| | - Emrah Eroglu
- Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, 34810, Istanbul, Turkey; Molecular Biology, Genetics, and Bioengineering Program, Sabanci University, 34956, Istanbul, Turkey.
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2
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Yang F, Smith MJ, Siow RCM, Aarsland D, Maret W, Mann GE. Interactions between zinc and NRF2 in vascular redox signalling. Biochem Soc Trans 2024; 52:269-278. [PMID: 38372426 PMCID: PMC10903478 DOI: 10.1042/bst20230490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 02/20/2024]
Abstract
Recent evidence highlights the importance of trace metal micronutrients such as zinc (Zn) in coronary and vascular diseases. Zn2+ plays a signalling role in modulating endothelial nitric oxide synthase and protects the endothelium against oxidative stress by up-regulation of glutathione synthesis. Excessive accumulation of Zn2+ in endothelial cells leads to apoptotic cell death resulting from dysregulation of glutathione and mitochondrial ATP synthesis, whereas zinc deficiency induces an inflammatory phenotype, associated with increased monocyte adhesion. Nuclear factor-E2-related factor 2 (NRF2) is a transcription factor known to target hundreds of different genes. Activation of NRF2 affects redox metabolism, autophagy, cell proliferation, remodelling of the extracellular matrix and wound healing. As a redox-inert metal ion, Zn has emerged as a biomarker in diagnosis and as a therapeutic approach for oxidative-related diseases due to its close link to NRF2 signalling. In non-vascular cell types, Zn has been shown to modify conformations of the NRF2 negative regulators Kelch-like ECH-associated Protein 1 (KEAP1) and glycogen synthase kinase 3β (GSK3β) and to promote degradation of BACH1, a transcriptional suppressor of select NRF2 genes. Zn can affect phosphorylation signalling, including mitogen-activated protein kinases (MAPK), phosphoinositide 3-kinases and protein kinase C, which facilitate NRF2 phosphorylation and nuclear translocation. Notably, several NRF2-targeted proteins have been suggested to modify cellular Zn concentration via Zn exporters (ZnTs) and importers (ZIPs) and the Zn buffering protein metallothionein. This review summarises the cross-talk between reactive oxygen species, Zn and NRF2 in antioxidant responses of vascular cells against oxidative stress and hypoxia/reoxygenation.
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Affiliation(s)
- Fan Yang
- School of Cardiovascular and Metabolic Medicine and Sciences, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, 150 Stamford Street, London SE1 9NH, U.K
| | - Matthew J Smith
- School of Cardiovascular and Metabolic Medicine and Sciences, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, 150 Stamford Street, London SE1 9NH, U.K
| | - Richard C M Siow
- School of Cardiovascular and Metabolic Medicine and Sciences, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, 150 Stamford Street, London SE1 9NH, U.K
| | - Dag Aarsland
- Department of Old Age Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College, London, U.K
- Centre for Age-Related Medicine, Stavanger University Hospital, Stavanger, Norway
| | - Wolfgang Maret
- Departments of Biochemistry and Nutritional Sciences, School of Life Course and Population Sciences, Faculty of Life Sciences and Medicine, King's College, London, U.K
| | - Giovanni E Mann
- School of Cardiovascular and Metabolic Medicine and Sciences, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, 150 Stamford Street, London SE1 9NH, U.K
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3
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Tian YM, Holdship P, To TQ, Ratcliffe PJ, Keeley TP. Comparative analysis of N-terminal cysteine dioxygenation and prolyl-hydroxylation as oxygen-sensing pathways in mammalian cells. J Biol Chem 2023; 299:105156. [PMID: 37572852 PMCID: PMC10506105 DOI: 10.1016/j.jbc.2023.105156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 07/25/2023] [Accepted: 08/07/2023] [Indexed: 08/14/2023] Open
Abstract
In animals, adaptation to changes in cellular oxygen levels is coordinated largely by 2-oxoglutarate-dependent prolyl-hydroxylase domain (PHD) dioxygenase family members, which regulate the stability of their hypoxia-inducible factor (HIF) substrates to promote expression of genes that adapt cells to hypoxia. Recently, 2-aminoethanethiol dioxygenase (ADO) was identified as a novel O2-sensing enzyme in animals. Through N-terminal cysteine dioxygenation and the N-degron pathway, ADO regulates the stability of a set of non-transcription factor substrates; the regulators of G-protein signaling 4, 5. and 16 and interleukin-32. Here, we set out to compare and contrast the in cellulo characteristics of ADO and PHD enzymes in an attempt to better understand their co-evolution in animals. We find that ADO operates to regulate the stability of its substrates rapidly and with similar O2-sensitivity to the PHD/HIF pathway. ADO appeared less sensitive to iron chelating agents or transition metal exposure than the PHD enzymes, possibly due to tighter catalytic-site Fe2+ coordination. Unlike the PHD/HIF pathway, the ADO/N-degron pathway was not subject to feedback by hypoxic induction of ADO, and induction of ADO substrates was well sustained in response to prolonged hypoxia. The data also reveal strong interactions between proteolytic regulation of targets by ADO and transcriptional induction of those targets, that shape integrated cellular responses to hypoxia. Collectively, our comparative analysis provides further insight into ADO/N-degron-mediated oxygen sensing and its integration into established mechanisms of oxygen homeostasis.
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Affiliation(s)
- Ya-Min Tian
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Philip Holdship
- Department of Earth Sciences, University of Oxford, Oxford, UK
| | - Trang Quynh To
- Department of Earth Sciences, University of Oxford, Oxford, UK
| | - Peter J Ratcliffe
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK; The Francis Crick Institute, London, UK.
| | - Thomas P Keeley
- Target Discovery Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
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4
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Li W, McLeod D, Ketzenberger JT, Kowalik G, Russo R, Li Z, Kay MW, Entcheva E. High-throughput optical sensing of peri-cellular oxygen in cardiac cells: system characterization, calibration, and testing. Front Bioeng Biotechnol 2023; 11:1214493. [PMID: 37397961 PMCID: PMC10313526 DOI: 10.3389/fbioe.2023.1214493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 06/07/2023] [Indexed: 07/04/2023] Open
Abstract
Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) represent a scalable experimental model relevant to human physiology. Oxygen consumption of hiPSC-CMs has not been studied in high-throughput (HT) format plates used in pre-clinical studies. Here, we provide comprehensive characterization and validation of a system for HT long-term optical measurements of peri-cellular oxygen in cardiac syncytia (human iPSC-CM and human cardiac fibroblasts), grown in glass-bottom 96-well plates. Laser-cut oxygen sensors having a ruthenium dye and an oxygen-insensitive reference dye were used. Ratiometric measurements (409 nm excitation) reflected dynamic changes in oxygen, as validated with simultaneous Clark electrode measurements. Emission ratios (653 nm vs. 510 nm) were calibrated for percent oxygen using two-point calibration. Time-dependent changes in the Stern-Volmer parameter, ksv, were observed during the initial 40-90 min of incubation, likely temperature-related. Effects of pH on oxygen measurements were negligible in the pH range of 4-8, with a small ratio reduction for pH > 10. Time-dependent calibration was implemented, and light exposure time was optimized (0.6-0.8 s) for oxygen measurements inside an incubator. Peri-cellular oxygen dropped to levels <5% within 3-10 h for densely-plated hiPSC-CMs in glass-bottom 96-well plates. After the initial oxygen decrease, samples either settled to low steady-state or exhibited intermittent peri-cellular oxygen dynamics. Cardiac fibroblasts showed slower oxygen depletion and higher steady-state levels without oscillations, compared to hiPSC-CMs. Overall, the system has great utility for long-term HT monitoring of peri-cellular oxygen dynamics in vitro for tracking cellular oxygen consumption, metabolic perturbations, and characterization of the maturation of hiPSC-CMs.
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Affiliation(s)
| | | | | | | | | | - Zhenyu Li
- Correspondence: Zhenyu Li, ; Matthew W. Kay, ; Emilia Entcheva,
| | - Matthew W. Kay
- Correspondence: Zhenyu Li, ; Matthew W. Kay, ; Emilia Entcheva,
| | - Emilia Entcheva
- Correspondence: Zhenyu Li, ; Matthew W. Kay, ; Emilia Entcheva,
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5
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Yang F, Smith MJ, Griffiths A, Morrell A, Chapple SJ, Siow RCM, Stewart T, Maret W, Mann GE. Vascular protection afforded by zinc supplementation in human coronary artery smooth muscle cells mediated by NRF2 signaling under hypoxia/reoxygenation. Redox Biol 2023; 64:102777. [PMID: 37315344 PMCID: PMC10363453 DOI: 10.1016/j.redox.2023.102777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 06/16/2023] Open
Abstract
Zinc (Zn) has antioxidant, anti-inflammatory and anti-proliferative actions, with Zn dysregulation associated with coronary ischemia/reperfusion injury and smooth muscle cell dysfunction. As the majority of studies concerning Zn have been conducted under non-physiological hyperoxic conditions, we compare the effects of Zn chelation or supplementation on total intracellular Zn content, antioxidant NRF2 targeted gene transcription and hypoxia/reoxygenation-induced reactive oxygen species generation in human coronary artery smooth muscle cells (HCASMC) pre-adapted to hyperoxia (18 kPa O2) or normoxia (5 kPa O2). Expression of the smooth muscle marker SM22-α was unaffected by lowering pericellular O2, whereas calponin-1 was significantly upregulated in cells under 5 kPa O2, indicating a more physiological contractile phenotype under 5 kPa O2. Inductively coupled plasma mass spectrometry established that Zn supplementation (10 μM ZnCl2 + 0.5 μM pyrithione) significantly increased total Zn content in HCASMC under 18 but not 5 kPa O2. Zn supplementation increased metallothionein mRNA expression and NRF2 nuclear accumulation in cells under 18 or 5 kPa O2. Notably, NRF2 regulated HO-1 and NQO1 mRNA expression in response to Zn supplementation was only upregulated in cells under 18 but not 5 kPa. Furthermore, whilst hypoxia increased intracellular glutathione (GSH) in cells pre-adapted to 18 but not 5 kPa O2, reoxygenation had negligible effects on GSH or total Zn content. Reoxygenation-induced superoxide generation in cells under 18 kPa O2 was abrogated by PEG-superoxide dismutase but not by PEG-catalase, and Zn supplementation, but not Zn chelation, attenuated reoxygenation-induced superoxide generation in cells under 18 but not 5kPaO2, consistent with a lower redox stress under physiological normoxia. Our findings highlight that culture of HCASMC under physiological normoxia recapitulates an in vivo contractile phenotype and that effects of Zn on NRF2 signaling are altered by oxygen tension.
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Affiliation(s)
- Fan Yang
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic 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 of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Alexander Griffiths
- London Metallomics Facility, Faculty of Life Sciences & Medicine, King's College London, UK
| | - Alexander Morrell
- London Metallomics Facility, Faculty of Life Sciences & Medicine, King's College London, UK
| | - Sarah J Chapple
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic 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 of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Theodora Stewart
- Research Management & Innovation Directorate (RMID), King's College London, UK
| | - Wolfgang Maret
- Departments of Biochemistry and Nutritional Sciences, School of Life Course & Population Sciences, Faculty of Life Sciences & Medicine, King's College London, UK
| | - Giovanni E Mann
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK.
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6
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Li W, McLeod D, Ketzenberger JT, Kowalik G, Russo R, Li Z, Kay MW, Entcheva E. High-throughput optical sensing of peri-cellular oxygen in cardiac cells: system characterization, calibration, and testing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.24.538133. [PMID: 37163022 PMCID: PMC10168216 DOI: 10.1101/2023.04.24.538133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) represent a scalable experimental model relevant to human physiology. Oxygen consumption of hiPSC-CMs has not been studied in high-throughput (HT) format plates used in pre-clinical studies. Here, we provide comprehensive characterization and validation of a system for HT long-term optical measurements of peri-cellular oxygen in cardiac syncytia (human iPSC-CM and human cardiac fibroblasts), grown in glass-bottom 96-well plates. Laser-cut oxygen sensors having a ruthenium dye and an oxygen-insensitive reference dye were used. Ratiometric measurements (409nm excitation) reflected dynamic changes in oxygen, as validated with simultaneous Clark electrode measurements. Emission ratios (653nm vs. 510nm) were calibrated for percent oxygen using two-point calibration. Time-dependent changes in the Stern-Volmer parameter, Ksv, were observed during the initial 40 min of incubation, likely temperature-related. Effects of pH on oxygen measurements were negligible in the pH range of 4 to 8, with a small ratio reduction for pH>10. Time-dependent calibration was implemented, and light exposure time was optimized (0.6 to 0.8s) for oxygen measurements inside an incubator. Peri-cellular oxygen dropped to levels < 5% within 3 -10 hours for densely-plated hiPSC-CMs in glass-bottom 96-well plates. After the initial oxygen decrease, samples either settled to low steady-state or exhibited intermittent peri-cellular oxygen dynamics. Cardiac fibroblasts showed slower oxygen depletion and higher steady-state levels without oscillations, compared to hiPSC-CMs. Overall, the system has great utility for long-term HT monitoring of peri-cellular oxygen dynamics in vitro for tracking cellular oxygen consumption, metabolic perturbations, and characterization of the maturation of hiPSC-CMs.
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7
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Smith MJ, Yang F, Griffiths A, Morrell A, Chapple SJ, Siow RCM, Stewart T, Maret W, Mann GE. Redox and metal profiles in human coronary endothelial and smooth muscle cells under hyperoxia, physiological normoxia and hypoxia: Effects of NRF2 signaling on intracellular zinc. Redox Biol 2023; 62:102712. [PMID: 37116256 PMCID: PMC10165141 DOI: 10.1016/j.redox.2023.102712] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/18/2023] [Accepted: 04/21/2023] [Indexed: 04/30/2023] Open
Abstract
Zinc is an important component of cellular antioxidant defenses and dysregulation of zinc homeostasis is a risk factor for coronary heart disease and ischemia/reperfusion injury. Intracellular homeostasis of metals, such as zinc, iron and calcium are interrelated with cellular responses to oxidative stress. Most cells experience significantly lower oxygen levels in vivo (2-10 kPa O2) compared to standard in vitro cell culture (18kPa O2). We report the first evidence that total intracellular zinc content decreases significantly in human coronary artery endothelial cells (HCAEC), but not in human coronary artery smooth muscle cells (HCASMC), after lowering of O2 levels from hyperoxia (18 kPa O2) to physiological normoxia (5 kPa O2) and hypoxia (1 kPa O2). This was paralleled by O2-dependent differences in redox phenotype based on measurements of glutathione, ATP and NRF2-targeted protein expression in HCAEC and HCASMC. NRF2-induced NQO1 expression was attenuated in both HCAEC and HCASMC under 5 kPa O2 compared to 18 kPa O2. Expression of the zinc efflux transporter ZnT1 increased in HCAEC under 5 kPa O2, whilst expression of the zinc-binding protein metallothionine (MT) decreased as O2 levels were lowered from 18 to 1 kPa O2. Negligible changes in ZnT1 and MT expression were observed in HCASMC. Silencing NRF2 transcription reduced total intracellular zinc under 18 kPa O2 in HCAEC with negligible changes in HCASMC, whilst NRF2 activation or overexpression increased zinc content in HCAEC, but not HCASMC, under 5 kPa O2. This study has identified cell type specific changes in the redox phenotype and metal profile in human coronary artery cells under physiological O2 levels. Our findings provide novel insights into the effect of NRF2 signaling on Zn content and may inform targeted therapies for cardiovascular diseases.
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Affiliation(s)
- Matthew J Smith
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Fan Yang
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Alexander Griffiths
- London Metallomics Facility, Faculty of Life Sciences & Medicine, King's College London, UK
| | - Alexander Morrell
- London Metallomics Facility, Faculty of Life Sciences & Medicine, King's College London, UK
| | - Sarah J Chapple
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic 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 of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK
| | - Theodora Stewart
- Research Management & Innovation Directorate (RMID), King's College London, UK
| | - Wolfgang Maret
- Departments of Biochemistry and Nutritional Sciences, School of Life Course & Population Sciences, Faculty of Life Sciences & Medicine, King's College London, UK
| | - Giovanni E Mann
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London, SE1 9NH, UK.
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8
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Steinert JR, Amal H. The contribution of an imbalanced redox signalling to neurological and neurodegenerative conditions. Free Radic Biol Med 2023; 194:71-83. [PMID: 36435368 DOI: 10.1016/j.freeradbiomed.2022.11.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/17/2022] [Accepted: 11/22/2022] [Indexed: 11/25/2022]
Abstract
Nitric oxide and other redox active molecules such as oxygen free radicals provide essential signalling in diverse neuronal functions, but their excess production and insufficient scavenging induces cytotoxic redox stress which is associated with numerous neurodegenerative and neurological conditions. A further component of redox signalling is mediated by a homeostatic regulation of divalent metal ions, the imbalance of which contributes to neuronal dysfunction. Additional antioxidant molecules such as glutathione and enzymes such as super oxide dismutase are involved in maintaining a physiological redox status within neurons. When cellular processes are perturbed and generation of free radicals overwhelms the antioxidants capacity of the neurons, a resulting redox damage leads to neuronal dysfunction and cell death. Cellular sources for production of redox-active molecules may include NADPH oxidases, mitochondria, cytochrome P450 and nitric oxide (NO)-generating enzymes, such as endothelial, neuronal and inducible NO synthases. Several neurodegenerative and developmental neurological conditions are associated with an imbalanced redox state as a result of neuroinflammatory processes leading to nitrosative and oxidative stress. Ongoing research aims at understanding the causes and consequences of such imbalanced redox homeostasis and its role in neuronal dysfunction.
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Affiliation(s)
- Joern R Steinert
- Division of Physiology, Pharmacology and Neuroscience, University of Nottingham, School of Life Sciences, Nottingham, NG7 2NR, UK.
| | - Haitham Amal
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
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9
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Casciello F, Kelly GM, Ramarao-Milne P, Kamal N, Stewart TA, Mukhopadhyay P, Kazakoff SH, Miranda M, Kim D, Davis FM, Hayward NK, Vertino PM, Waddell N, Gannon F, Lee JS. Combined inhibition of G9a and EZH2 suppresses tumor growth via synergistic induction of IL24-mediated apoptosis. Cancer Res 2022; 82:1208-1221. [PMID: 35149587 DOI: 10.1158/0008-5472.can-21-2218] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 12/07/2021] [Accepted: 02/09/2022] [Indexed: 11/16/2022]
Abstract
G9a and EZH2 are two histone methyltransferases commonly upregulated in several cancer types, yet the precise roles that these enzymes play cooperatively in cancer is unclear. We demonstrate here that frequent concurrent upregulation of both G9a and EZH2 occurs in several human tumors. These methyltransferases cooperatively repressed molecular pathways responsible for tumor cell death. In genetically distinct tumor subtypes, concomitant inhibition of G9a and EZH2 potently induced tumor cell death, highlighting the existence of tumor cell survival dependency at the epigenetic level. G9a and EZH2 synergistically repressed expression of genes involved in the induction of endoplasmic reticulum (ER) stress and the production of reactive oxygen species. IL24 was essential for the induction of tumor cell death and was identified as a common target of G9a and EZH2. Loss-of-function of G9a and EZH2 activated the IL24-ER stress axis and increased apoptosis in cancer cells while not affecting normal cells. These results indicate that G9a and EZH2 promotes the evasion of ER stress-mediated apoptosis by repressing IL24 transcription, therefore suggesting that their inhibition may represent a potential therapeutic strategy for solid cancers.
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Affiliation(s)
| | | | - Priya Ramarao-Milne
- Transformational Bioinformatics, Commonwealth Scientific and Industrial Research Organisation
| | - Nabilah Kamal
- Epigenetics and Disease Laboratory, QIMR Berghofer Medical Research Institute
| | | | | | | | | | - Dorim Kim
- Epigenetics and Disease Laboratory, QIMR Berghofer Medical Research Institute
| | - Felicity M Davis
- School of Medical Sciences, EMBL Australia Node in Single Molecule Science
| | | | - Paula M Vertino
- School of Medicine and Dentistry, University of Rochester Medical Center
| | - Nicola Waddell
- Medical Genomics Laboratory, QIMR Berghofer Medical Research Institute
| | - Frank Gannon
- Cancer, QIMR Berghofer Medical Research Institute
| | - Jason S Lee
- Epigenetics and Disease Laboratory, QIMR Berghofer Medical Research Institute
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10
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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: 43] [Impact Index Per Article: 10.8] [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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11
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Hamstra SI, Whitley KC, Baranowski RW, Kurgan N, Braun JL, Messner HN, Fajardo VA. The role of phospholamban and GSK3 in regulating rodent cardiac SERCA function. Am J Physiol Cell Physiol 2020; 319:C694-C699. [PMID: 32755452 DOI: 10.1152/ajpcell.00318.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac contractile function is largely mediated by the regulation of Ca2+ cycling throughout the lifespan. The sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA) pump is paramount to cardiac Ca2+ regulation, and it is well established that SERCA dysfunction pathologically contributes to cardiomyopathy and heart failure. Phospholamban (PLN) is a well-known inhibitor of the SERCA pump and its regulation of SERCA2a-the predominant cardiac SERCA isoform-contributes significantly to proper cardiac function. Glycogen synthase kinase 3 (GSK3) is a serine/threonine kinase involved in several metabolic pathways, and we and others have shown that it regulates SERCA function. In this mini-review, we highlight the underlying mechanisms behind GSK3's regulation of SERCA function specifically discussing changes in SERCA2a and PLN expression and its potential protection against oxidative stress. Ultimately, these recent findings that we discuss could have clinical implications in the treatment and prevention of cardiomyopathies and heart failure.
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Affiliation(s)
- Sophie I Hamstra
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Kennedy C Whitley
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Ryan W Baranowski
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Nigel Kurgan
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Jessica L Braun
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Holt N Messner
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - Val A Fajardo
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
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12
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Endothelial Ca 2+ Signaling, Angiogenesis and Vasculogenesis: just What It Takes to Make a Blood Vessel. Int J Mol Sci 2019; 20:ijms20163962. [PMID: 31416282 PMCID: PMC6721072 DOI: 10.3390/ijms20163962] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/09/2019] [Accepted: 08/13/2019] [Indexed: 12/13/2022] Open
Abstract
It has long been known that endothelial Ca2+ signals drive angiogenesis by recruiting multiple Ca2+-sensitive decoders in response to pro-angiogenic cues, such as vascular endothelial growth factor, basic fibroblast growth factor, stromal derived factor-1α and angiopoietins. Recently, it was shown that intracellular Ca2+ signaling also drives vasculogenesis by stimulation proliferation, tube formation and neovessel formation in endothelial progenitor cells. Herein, we survey how growth factors, chemokines and angiogenic modulators use endothelial Ca2+ signaling to regulate angiogenesis and vasculogenesis. The endothelial Ca2+ response to pro-angiogenic cues may adopt different waveforms, ranging from Ca2+ transients or biphasic Ca2+ signals to repetitive Ca2+ oscillations, and is mainly driven by endogenous Ca2+ release through inositol-1,4,5-trisphosphate receptors and by store-operated Ca2+ entry through Orai1 channels. Lysosomal Ca2+ release through nicotinic acid adenine dinucleotide phosphate-gated two-pore channels is, however, emerging as a crucial pro-angiogenic pathway, which sustains intracellular Ca2+ mobilization. Understanding how endothelial Ca2+ signaling regulates angiogenesis and vasculogenesis could shed light on alternative strategies to induce therapeutic angiogenesis or interfere with the aberrant vascularization featuring cancer and intraocular disorders.
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Keeley TP, Mann GE. Defining Physiological Normoxia for Improved Translation of Cell Physiology to Animal Models and Humans. Physiol Rev 2019; 99:161-234. [PMID: 30354965 DOI: 10.1152/physrev.00041.2017] [Citation(s) in RCA: 169] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The extensive oxygen gradient between the air we breathe (Po2 ~21 kPa) and its ultimate distribution within mitochondria (as low as ~0.5-1 kPa) is testament to the efforts expended in limiting its inherent toxicity. It has long been recognized that cell culture undertaken under room air conditions falls short of replicating this protection in vitro. Despite this, difficulty in accurately determining the appropriate O2 levels in which to culture cells, coupled with a lack of the technology to replicate and maintain a physiological O2 environment in vitro, has hindered addressing this issue thus far. In this review, we aim to address the current understanding of tissue Po2 distribution in vivo and summarize the attempts made to replicate these conditions in vitro. The state-of-the-art techniques employed to accurately determine O2 levels, as well as the issues associated with reproducing physiological O2 levels in vitro, are also critically reviewed. We aim to provide the framework for researchers to undertake cell culture under O2 levels relevant to specific tissues and organs. We envisage that this review will facilitate a paradigm shift, enabling translation of findings under physiological conditions in vitro to disease pathology and the design of novel therapeutics.
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Affiliation(s)
- Thomas P Keeley
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London , London , United Kingdom
| | - Giovanni E Mann
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, Faculty of Life Sciences and Medicine, King's College London , London , United Kingdom
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