
The extensive oxygen gradient between the air we breathe and its ultimate distribution within mitochondria (under 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. Our laboratory provides facilities for researchers to undertake cell culture under O2 levels relevant to specific tissues to enable translation of findings under physiological conditions in vitro to disease pathology and discovery of novel therapeutics.
Projects

Hypoxia and Physiological Oxygen in the Brain
The understanding the mechanisms regulating neurovascular redox defenses are key for improved clinical translation for stroke and age-related neurodegenerative conditions. Our previous studies in a rodent model of ischemic stroke established that activation of Nrf2 defense enzymes by treatment with dietary phytochemicals afford protection against neurovascular and neurological deficits. We now investigate the actions of potential therapeutic compounds and phytochemicals on antioxidant defence pathways in mouse and human brain microvascular endothelial cells adapted long-term to normoxic and hypoxic oxygen levels to assess the mechanisms by which they confer protection under physiological oxygen levels.

Metals in Hypoxia / Reoxygenation
We are investigating the mechanisms by which changes in intracellular metals contribute to human coronary artery endothelial and smooth muscle cell injury following ischaemia and reperfusion using novel metallomic analytical methods in collaboration with the London Metallomics Facility through funding from Heart Research UK. Cells are adapted long-term to normoxic (5 kPa) and hypoxic (1 kPa) oxygen levels to assess whether perturbations in redox signalling pathways alter the metallomic profile.
Microfluidics in Physoxia and Hypoxia
Vascular cells are continually exposed to biomechanical forces including fluid shear stress (FSS) and cyclic stretch. We are using 3D-microfluidic chip platforms to culture arterial, venous and microvascular endothelial cells under defined FSS within physiological oxygen environments to better recapitulate the in vivo environment to further understand the importance of mechanotranduction in vascular health, ageing and the pathology of cardiovascular diseases for clinical translation and drug descovery.
Publications
Altun HY, Secilmis M, Yang F, Caglar TA, Vatandaslar E, Toy MF, Vilain S, Mann GE, Öztürk G, Eroglu E (2024) Visualizing Hydrogen Peroxide and Nitric Oxide Dynamics in Endothelial Cells Using Multispectral Imaging under Controlled Oxygen Conditions Free Rad Biol Med. (in press).
Yang F, Smith MJ, Griffiths A, Morrell A, Chapple SJ, Siow RCM, Stewart T, Maret W, Mann GE (2023) Vascular protection afforded by zinc supplementation in human coronary artery smooth muscle cells mediated by NRF2 signaling under hypoxia/reoxygenation Redox Biol. 64:102777.
Smith MJ, Yang F, Griffiths A, Morrell A, Chapple SJ, Siow RCM, Stewart T, Maret W, Mann GE (2023) 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. 62:102712.
Sevimli G, Smith MJ, Caglar TA, Bilirc S, Secilmis M, Altuna HY, Yigit EN, Yang F, Keeley TP, Malli R, Öztürk G, Mann GE, Eroglu E (2022) Nitric oxide biosensor uncovers diminished ferrous iron-dependency of cultured cells adapted to physiological oxygen levels Redox Biol. 53:102319.
Furfaro AL, Loi G, Ivaldo C, Passalacqua M, Pietra G, Mann GE, Nitti M (2022) HO-1 Limits the Efficacy of Vemurafenib/PLX4032 in BRAFV600E Mutated Melanoma Cells Adapted to Physiological Normoxia or Hypoxia Antioxidants 11:1171.
Sies H, Belousov VV, Chandel NS, Davies MJ, Jones DP, Mann GE, Murphy MP, Yamamoto M, Winterbourn C (2022) Defining roles of specific reactive oxygen species (ROS) in cell biology and physiology. Nat Rev Mol Cell Biol. 23:499-515.
Warpsinski G, Smith MJ, Srivastava S, Keeley TP, Siow RC, Fraser PA, Mann GE (2020) Nrf2-regulated redox signaling in brain endothelial cells adapted to physiological oxygen levels: Consequences for sulforaphane mediated protection against hypoxia-reoxygenation. Redox Biol. 37:101708.
Keeley TP, Mann GE (2019) Defining Physiological Normoxia for Improved Translation of Cell Physiology to Animal Models and Humans. Physiol Rev. 99:161-234.
Keeley TP, Siow RC, Jacob R, Mann GE (2018) Reduced SERCA activity underlies dysregulation of Ca2+ homeostasis under atmospheric O2 levels. FASEB J. 32:2531-2538.
Keeley TP, Siow RC, Jacob R, Mann GE (2017) A PP2A-mediated feedback mechanism controls Ca2+dependent NO synthesis under physiological oxygen. FASEB J. 31:5172-5183.
Chapple SJ, Keeley TP, Mastronicola D, Arno M, Vizcay-Barrena G, Fleck R, Siow RC, Mann GE (2016) Bach1 differentially regulates distinct Nrf2-dependent genes in human venous and coronary artery endothelial cells adapted to physiological oxygen levels. Free Radic Biol Med. 92:152-162.
Kumar A, Dailey LA, Swedrowska M, Siow RC, Mann GE, Vizcay-Barrena G, Arno M, Mudway IS, Forbes B (2016) Quantifying the magnitude of the oxygen artefact inherent in culturing airway cells under atmospheric oxygen versus physiological levels. FEBS Lett. 590:258-269.
El-Alami M, Viña-Almunia J, Gambini J, Mas-Bargues C, Siow RC, Peñarrocha M, Mann GE, Borrás C, Viña J (2014) Activation of p38, p21, and NRF-2 mediates decreased proliferation of human dental pulp stem cells cultured under 21% O2. Stem Cell Reports. 3:566-573.
Meetings & Webinars
Role of Metals in Brain Health and Disease - 11 May 2022
Our second online symposium with London Metallomics Facility and Ageing Research at King's (ARK) highlighted the roles that metals play in normal brain function and disease, including recent developments in interventions for treatment of neurodegenerative diseases, the significance of redox signalling, and the recent advances in bioimaging technology to underpin these important scientific questions. The symposium featured speakers from Faculty of Life Sciences & Medicine and Institute of Psychiatry, Psychology & Neuroscience at King's, University College London, University of Warwick and Albert Einstein College of Medicine, USA. The keynote lecture given by Prof Costantino Iadecola, Weill Cornell Medicine, USA was on ‘Innate and adaptive immunity in stroke and dementia: challenges and opportunities'.
Metal Fingerprints in Normal Cell States & Disease Symposium - 5 May 2021
The field of metallomics utilises analytical tools to understand the biological roles of metals in biological space and time using elemental mass spectrometry. The characteristic metallomes change within the life span of cells and tissues. Our current research associated with the London Metallomics Facility (LMF) focuses on applications of metal profiling in brain and cardiovascular system, exploiting our Physiological Oxygen Lab to investigate metal profiles of cells grown under defined O2 concentrations. Together with the LMF, we will celebrate a King's Together Award with a virtual symposium including keynote speakers: Prof Sir Peter Ratcliffe FRS, Clinical Director, Francis Crick Institute and 2019 Noble Laureate in Physiology or Medicine for "discoveries of how cells sense and adapt to oxygen availability", and Prof Fiona Watt FRS, Executive Director, Medical Research Council.
Webinars
Physiological oxygen levels for translation of cell physiology to man (Elsevier / Baker-Ruskinn)
Defining physiological normoxia in cultured cells for translation to animal models and man (Nature / BMG Labtech)
Physiological oxygen and Nrf2 in vascular cells and reperfusion injury (Antiox Webinar Series)
The Superoxide Radical Switch in the Biology of Nitric Oxide and Peroxynitrite (Physiological Reviews Podcast, including discussion of the importance of physiologically relevant oxygen levels)
Physiological Oxygen Cell Culture Workshops
Fourth Workshop Nov 2018 (including Metallomics)
Fifth Workshop Sept 2019 (including Metallomics)
Sixth Physiological Oxygen Workshop
This workshop with London Metallomics Facility (LMF) took place in December 2021, including scientific talks and practical demonstrations in the Physiological Oxygen Laboratory and LMF. We are grateful to Baker-Ruskinn, Labtech International and BMG Labtech for supporting the workshop. Program details and recorded talks below.

7th Physiological Oxygen Workshop: 'Drug discovery and high-throughput screening'
The Physiological Oxygen Laboratory hosted a Pharma / Industry workshop in October 2022 with lectures on the importance screening therapeutics in cell models under physiological oxygen levels and demonstrations of Baker-Ruskinn workstations, Thermo Fisher and Etaluma imaging equipment, Lucid Scientific cellular respiration measurements and BMG Labtech atmosphere controlled plate reader. Programme details below:

BenBedPhar Training School 2024
We hosted the 2024 Training School (5-8 March) for BenBedPhar EU Cost Action ‘Bench to bedside transition for pharmacological regulation of Nrf2 in non-communicable diseases’, focused on the importance of physiological oxygen when investigating cellular redox signalling to improve clinical translation. Participants from 9 countries included 25 students, 8 faculty and representatives from 6 companies. We are grateful for support from Baker, Labtech International, Lucid Scientific and BMG Labtech.
Redox Imaging Workshop 8 June 2024
We are pleased to partner with the redox imaging workshop for early career researchers hosted by the Institute of Health Sciences and Technologies (SABITA) at Istanbul Medipol University, Türkiye. This satellite event on the theme “Seeing is Believing" is associated with the Society for Free Radical Research Europe meeting and chaired by Emrah Eroğlu. Details and registration via the link below.
HypoxEU Forum
The HypoxEU forum disseminates discoveries in responses to variations in cellular and tissue oxygenation. The second HypoxEU forum on 9 December 2021 brought together international researchers as a platform for sharing and connecting through their passion for oxygen research. The forum is supported by Baker-Ruskinn and their academic network.
Projects

Hypoxia and Physiological Oxygen in the Brain
The understanding the mechanisms regulating neurovascular redox defenses are key for improved clinical translation for stroke and age-related neurodegenerative conditions. Our previous studies in a rodent model of ischemic stroke established that activation of Nrf2 defense enzymes by treatment with dietary phytochemicals afford protection against neurovascular and neurological deficits. We now investigate the actions of potential therapeutic compounds and phytochemicals on antioxidant defence pathways in mouse and human brain microvascular endothelial cells adapted long-term to normoxic and hypoxic oxygen levels to assess the mechanisms by which they confer protection under physiological oxygen levels.

Metals in Hypoxia / Reoxygenation
We are investigating the mechanisms by which changes in intracellular metals contribute to human coronary artery endothelial and smooth muscle cell injury following ischaemia and reperfusion using novel metallomic analytical methods in collaboration with the London Metallomics Facility through funding from Heart Research UK. Cells are adapted long-term to normoxic (5 kPa) and hypoxic (1 kPa) oxygen levels to assess whether perturbations in redox signalling pathways alter the metallomic profile.
Microfluidics in Physoxia and Hypoxia
Vascular cells are continually exposed to biomechanical forces including fluid shear stress (FSS) and cyclic stretch. We are using 3D-microfluidic chip platforms to culture arterial, venous and microvascular endothelial cells under defined FSS within physiological oxygen environments to better recapitulate the in vivo environment to further understand the importance of mechanotranduction in vascular health, ageing and the pathology of cardiovascular diseases for clinical translation and drug descovery.
Publications
Altun HY, Secilmis M, Yang F, Caglar TA, Vatandaslar E, Toy MF, Vilain S, Mann GE, Öztürk G, Eroglu E (2024) Visualizing Hydrogen Peroxide and Nitric Oxide Dynamics in Endothelial Cells Using Multispectral Imaging under Controlled Oxygen Conditions Free Rad Biol Med. (in press).
Yang F, Smith MJ, Griffiths A, Morrell A, Chapple SJ, Siow RCM, Stewart T, Maret W, Mann GE (2023) Vascular protection afforded by zinc supplementation in human coronary artery smooth muscle cells mediated by NRF2 signaling under hypoxia/reoxygenation Redox Biol. 64:102777.
Smith MJ, Yang F, Griffiths A, Morrell A, Chapple SJ, Siow RCM, Stewart T, Maret W, Mann GE (2023) 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. 62:102712.
Sevimli G, Smith MJ, Caglar TA, Bilirc S, Secilmis M, Altuna HY, Yigit EN, Yang F, Keeley TP, Malli R, Öztürk G, Mann GE, Eroglu E (2022) Nitric oxide biosensor uncovers diminished ferrous iron-dependency of cultured cells adapted to physiological oxygen levels Redox Biol. 53:102319.
Furfaro AL, Loi G, Ivaldo C, Passalacqua M, Pietra G, Mann GE, Nitti M (2022) HO-1 Limits the Efficacy of Vemurafenib/PLX4032 in BRAFV600E Mutated Melanoma Cells Adapted to Physiological Normoxia or Hypoxia Antioxidants 11:1171.
Sies H, Belousov VV, Chandel NS, Davies MJ, Jones DP, Mann GE, Murphy MP, Yamamoto M, Winterbourn C (2022) Defining roles of specific reactive oxygen species (ROS) in cell biology and physiology. Nat Rev Mol Cell Biol. 23:499-515.
Warpsinski G, Smith MJ, Srivastava S, Keeley TP, Siow RC, Fraser PA, Mann GE (2020) Nrf2-regulated redox signaling in brain endothelial cells adapted to physiological oxygen levels: Consequences for sulforaphane mediated protection against hypoxia-reoxygenation. Redox Biol. 37:101708.
Keeley TP, Mann GE (2019) Defining Physiological Normoxia for Improved Translation of Cell Physiology to Animal Models and Humans. Physiol Rev. 99:161-234.
Keeley TP, Siow RC, Jacob R, Mann GE (2018) Reduced SERCA activity underlies dysregulation of Ca2+ homeostasis under atmospheric O2 levels. FASEB J. 32:2531-2538.
Keeley TP, Siow RC, Jacob R, Mann GE (2017) A PP2A-mediated feedback mechanism controls Ca2+dependent NO synthesis under physiological oxygen. FASEB J. 31:5172-5183.
Chapple SJ, Keeley TP, Mastronicola D, Arno M, Vizcay-Barrena G, Fleck R, Siow RC, Mann GE (2016) Bach1 differentially regulates distinct Nrf2-dependent genes in human venous and coronary artery endothelial cells adapted to physiological oxygen levels. Free Radic Biol Med. 92:152-162.
Kumar A, Dailey LA, Swedrowska M, Siow RC, Mann GE, Vizcay-Barrena G, Arno M, Mudway IS, Forbes B (2016) Quantifying the magnitude of the oxygen artefact inherent in culturing airway cells under atmospheric oxygen versus physiological levels. FEBS Lett. 590:258-269.
El-Alami M, Viña-Almunia J, Gambini J, Mas-Bargues C, Siow RC, Peñarrocha M, Mann GE, Borrás C, Viña J (2014) Activation of p38, p21, and NRF-2 mediates decreased proliferation of human dental pulp stem cells cultured under 21% O2. Stem Cell Reports. 3:566-573.
Meetings & Webinars
Role of Metals in Brain Health and Disease - 11 May 2022
Our second online symposium with London Metallomics Facility and Ageing Research at King's (ARK) highlighted the roles that metals play in normal brain function and disease, including recent developments in interventions for treatment of neurodegenerative diseases, the significance of redox signalling, and the recent advances in bioimaging technology to underpin these important scientific questions. The symposium featured speakers from Faculty of Life Sciences & Medicine and Institute of Psychiatry, Psychology & Neuroscience at King's, University College London, University of Warwick and Albert Einstein College of Medicine, USA. The keynote lecture given by Prof Costantino Iadecola, Weill Cornell Medicine, USA was on ‘Innate and adaptive immunity in stroke and dementia: challenges and opportunities'.
Metal Fingerprints in Normal Cell States & Disease Symposium - 5 May 2021
The field of metallomics utilises analytical tools to understand the biological roles of metals in biological space and time using elemental mass spectrometry. The characteristic metallomes change within the life span of cells and tissues. Our current research associated with the London Metallomics Facility (LMF) focuses on applications of metal profiling in brain and cardiovascular system, exploiting our Physiological Oxygen Lab to investigate metal profiles of cells grown under defined O2 concentrations. Together with the LMF, we will celebrate a King's Together Award with a virtual symposium including keynote speakers: Prof Sir Peter Ratcliffe FRS, Clinical Director, Francis Crick Institute and 2019 Noble Laureate in Physiology or Medicine for "discoveries of how cells sense and adapt to oxygen availability", and Prof Fiona Watt FRS, Executive Director, Medical Research Council.
Webinars
Physiological oxygen levels for translation of cell physiology to man (Elsevier / Baker-Ruskinn)
Defining physiological normoxia in cultured cells for translation to animal models and man (Nature / BMG Labtech)
Physiological oxygen and Nrf2 in vascular cells and reperfusion injury (Antiox Webinar Series)
The Superoxide Radical Switch in the Biology of Nitric Oxide and Peroxynitrite (Physiological Reviews Podcast, including discussion of the importance of physiologically relevant oxygen levels)
Physiological Oxygen Cell Culture Workshops
Fourth Workshop Nov 2018 (including Metallomics)
Fifth Workshop Sept 2019 (including Metallomics)
Sixth Physiological Oxygen Workshop
This workshop with London Metallomics Facility (LMF) took place in December 2021, including scientific talks and practical demonstrations in the Physiological Oxygen Laboratory and LMF. We are grateful to Baker-Ruskinn, Labtech International and BMG Labtech for supporting the workshop. Program details and recorded talks below.

7th Physiological Oxygen Workshop: 'Drug discovery and high-throughput screening'
The Physiological Oxygen Laboratory hosted a Pharma / Industry workshop in October 2022 with lectures on the importance screening therapeutics in cell models under physiological oxygen levels and demonstrations of Baker-Ruskinn workstations, Thermo Fisher and Etaluma imaging equipment, Lucid Scientific cellular respiration measurements and BMG Labtech atmosphere controlled plate reader. Programme details below:

BenBedPhar Training School 2024
We hosted the 2024 Training School (5-8 March) for BenBedPhar EU Cost Action ‘Bench to bedside transition for pharmacological regulation of Nrf2 in non-communicable diseases’, focused on the importance of physiological oxygen when investigating cellular redox signalling to improve clinical translation. Participants from 9 countries included 25 students, 8 faculty and representatives from 6 companies. We are grateful for support from Baker, Labtech International, Lucid Scientific and BMG Labtech.
Redox Imaging Workshop 8 June 2024
We are pleased to partner with the redox imaging workshop for early career researchers hosted by the Institute of Health Sciences and Technologies (SABITA) at Istanbul Medipol University, Türkiye. This satellite event on the theme “Seeing is Believing" is associated with the Society for Free Radical Research Europe meeting and chaired by Emrah Eroğlu. Details and registration via the link below.
HypoxEU Forum
The HypoxEU forum disseminates discoveries in responses to variations in cellular and tissue oxygenation. The second HypoxEU forum on 9 December 2021 brought together international researchers as a platform for sharing and connecting through their passion for oxygen research. The forum is supported by Baker-Ruskinn and their academic network.
Our Partners
We partner with the London Metallomics Facility at King's, Baker-Ruskinn, BMG Labtech, Lucid Scientific and BioGenium Microsystems for R&D in novel physiological oxygen cell culture technologies in addition to the Francis Crick Institute with grant funding from Heart Research UK and the British Heart Foundation.

Heart Research UK

British Heart Foundation

The Francis Crick Institute
