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Chettouh-Hammas N, Grillon C. Physiological skin oxygen levels: An important criterion for skin cell functionality and therapeutic approaches. Free Radic Biol Med 2024; 222:259-274. [PMID: 38908804 DOI: 10.1016/j.freeradbiomed.2024.06.015] [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: 04/29/2024] [Revised: 06/15/2024] [Accepted: 06/18/2024] [Indexed: 06/24/2024]
Abstract
The skin is made up of different layers with various gradients, which maintain a complex microenvironment, particularly in terms of oxygen levels. However, all types of skin cells are cultured in conventional incubators that do not reproduce physiological oxygen levels. Instead, they are cultured at atmospheric oxygen levels, a condition that is far removed from physiology and may lead to the generation of free radicals known to induce skin ageing. This review aims to summarize the current literature on the effect of physiological oxygen levels on skin cells, highlight the shortcomings of current in vitro models, and demonstrate the importance of respecting skin oxygen levels. We begin by clarifying the terminology used about oxygen levels and describe the specific distribution of oxygen in the skin. We review and discuss how skin cells adapt their oxygen consumption and metabolism to oxygen levels environment, as well as the changes that are induced, particularly, their redox state, life cycle and functions. We examine the effects of oxygen on both simple culture models and more complex reconstructed skin models. Finally, we present the implications of oxygen modulation for a more therapeutic approach.
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Affiliation(s)
- Nadira Chettouh-Hammas
- Center for Molecular Biophysics UPR4301 CNRS, Rue Charles Sadron, 45071, Orléans, Cedex 2, France.
| | - Catherine Grillon
- Center for Molecular Biophysics UPR4301 CNRS, Rue Charles Sadron, 45071, Orléans, Cedex 2, France.
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Ryan S, Crowe L, Almeida Cruz SN, Galbraith MD, O'Brien C, Hammer JA, Bergin R, Kellett SK, Markey GE, Benson TM, Fagan O, Espinosa JM, Conlon N, Donohoe CL, McKiernan S, Hogan AE, McNamee EN, Furuta GT, Menard-Katcher C, Masterson JC. Metabolic dysfunction mediated by HIF-1α contributes to epithelial differentiation defects in eosinophilic esophagitis. J Allergy Clin Immunol 2024:S0091-6749(24)00867-4. [PMID: 39209164 DOI: 10.1016/j.jaci.2024.07.030] [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: 03/12/2024] [Revised: 07/10/2024] [Accepted: 07/26/2024] [Indexed: 09/04/2024]
Abstract
BACKGROUND Investigating the contributory role that epithelial cell metabolism plays in allergic inflammation is a key factor to understanding what influences dysfunction and the pathogenesis of the allergic disease eosinophilic esophagitis (EoE). We previously highlighted that the absence of hypoxia signaling through hypoxia-inducible factor (HIF)-1α in EoE contributes to esophageal epithelial dysfunction. However, metabolic regulation by HIF-1α has not been explored in esophageal allergy. OBJECTIVES We sought to define the role of HIF-1α-mediated metabolic dysfunction in esophageal epithelial differentiation processes and barrier function in EoE. METHODS In RNA sequencing of EoE patient biopsy samples, we observed the expression pattern of key genes involved in mitochondrial metabolism/oxidative phosphorylation (OXPHOS) and glycolysis. Seahorse bioenergetics analysis was performed on EPC2-hTERT cells to decipher the metabolic processes involved in epithelial differentiation processes. In addition, air-liquid interface cultures were used to delineate metabolic dependency mechanisms required for epithelial differentiation. RESULTS Transcriptomic analysis identified an increase in genes associated with OXPHOS in patients with EoE. Epithelial origin of this signature was confirmed by complex V immunofluorescence of patient biopsy samples. Bioenergetic analysis in vitro revealed that differentiated epithelium was less reliant on OXPHOS compared with undifferentiated epithelium. Increased OXPHOS potential and reduced glycolytic capacity was mirrored in HIF1A-knockdown EPC2-hTERT cells that exhibited a significant absence of terminal markers of epithelial differentiation, including involucrin. Pharmacologic glucose transport inhibition phenocopied this, while rescue of the HIF-1α-deficient phenotype using the pan-prolyl hydroxylase inhibitor dimethyloxalylglycine resulted in restored expression of epithelial differentiation markers. CONCLUSIONS An OXPHOS-dominated metabolic pattern in EoE patients, brought about largely by the absence of HIF-1α-mediated glycolysis, is linked with the deficit in esophageal epithelial differentiation.
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Affiliation(s)
- Sinéad Ryan
- Allergy, Inflammation, and Remodeling Research Laboratory, Department of Biology, National University of Ireland, Maynooth, Ireland; Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Ireland
| | - Louise Crowe
- Allergy, Inflammation, and Remodeling Research Laboratory, Department of Biology, National University of Ireland, Maynooth, Ireland; Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Ireland
| | - Sofía N Almeida Cruz
- Allergy, Inflammation, and Remodeling Research Laboratory, Department of Biology, National University of Ireland, Maynooth, Ireland; Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Ireland
| | - Matthew D Galbraith
- Linda Crinc Institute for Down Syndrome, University of Colorado Anschutz Medical Campus, Aurora, Colo; Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, Colo
| | - Carol O'Brien
- Allergy, Inflammation, and Remodeling Research Laboratory, Department of Biology, National University of Ireland, Maynooth, Ireland; Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Ireland
| | - Juliet A Hammer
- Gastrointestinal Eosinophilic Diseases Program, Digestive Health Institute, Children's Hospital Colorado, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colo
| | - Ronan Bergin
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Ireland
| | - Shauna K Kellett
- Allergy, Inflammation, and Remodeling Research Laboratory, Department of Biology, National University of Ireland, Maynooth, Ireland; Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Ireland
| | - Gary E Markey
- Allergy, Inflammation, and Remodeling Research Laboratory, Department of Biology, National University of Ireland, Maynooth, Ireland; Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Ireland
| | - Taylor M Benson
- Allergy, Inflammation, and Remodeling Research Laboratory, Department of Biology, National University of Ireland, Maynooth, Ireland; Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Ireland
| | - Olga Fagan
- Department of Gastroenterology, St James's Hospital, Dublin, Ireland
| | - Joaquin M Espinosa
- Linda Crinc Institute for Down Syndrome, University of Colorado Anschutz Medical Campus, Aurora, Colo
| | - Niall Conlon
- Department of Allergy and Immunology, St James's Hospital, Dublin, Ireland
| | - Claire L Donohoe
- National Centre for Oesophageal and Gastric Cancer, Trinity St James's Cancer Institute, St James's Hospital, Trinity College, Dublin, Ireland
| | - Susan McKiernan
- Department of Gastroenterology, St James's Hospital, Dublin, Ireland
| | - Andrew E Hogan
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Ireland; Department of Biology, Obesity Immunology Research Group, Maynooth University, Maynooth, Ireland
| | - Eóin N McNamee
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Ireland; Department of Biology, Mucosal Immunology Research Laboratory, National University of Ireland, Maynooth, Ireland
| | - Glenn T Furuta
- Gastrointestinal Eosinophilic Diseases Program, Digestive Health Institute, Children's Hospital Colorado, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colo
| | - Calies Menard-Katcher
- Gastrointestinal Eosinophilic Diseases Program, Digestive Health Institute, Children's Hospital Colorado, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colo
| | - Joanne C Masterson
- Allergy, Inflammation, and Remodeling Research Laboratory, Department of Biology, National University of Ireland, Maynooth, Ireland; Kathleen Lonsdale Institute for Human Health Research, Maynooth University, Maynooth, Ireland; Gastrointestinal Eosinophilic Diseases Program, Digestive Health Institute, Children's Hospital Colorado, Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colo.
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Chettouh-Hammas N, Fasani F, Boileau A, Gosset D, Busco G, Grillon C. Improvement of Antioxidant Defences in Keratinocytes Grown in Physioxia: Comparison of 2D and 3D Models. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2023; 2023:6829931. [PMID: 37360501 PMCID: PMC10290565 DOI: 10.1155/2023/6829931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/25/2023] [Accepted: 05/27/2023] [Indexed: 06/28/2023]
Abstract
Keratinocytes prevent skin photoaging by ensuring the defence against oxidative stress, an excessive production of reactive oxygen species (ROS). They are localized within the epidermis where the oxygen level (1-3% O2), named physioxia, is low compared to other organs. Oxygen is essential for life but also generates ROS. Most of the in vitro studies on keratinocyte antioxidant capacities are performed under atmospheric oxygen, named normoxia, which is very far from the physiological microenvironment, thus submitting cells to an overoxygenation. The present study is aimed at investigating the antioxidant status of keratinocyte grown under physioxia in both 2D and 3D models. First, we show that the basal antioxidant profiles of keratinocytes display important differences when comparing the HaCaT cell line, primary keratinocytes (NHEK), reconstructed epidermis (RHE), and skin explants. Physioxia was shown to promote a strong proliferation of keratinocytes in monolayers and in RHE, resulting in a thinner epidermis likely due to a slowdown in cell differentiation. Interestingly, cells in physioxia exhibited a lower ROS production upon stress, suggesting a better protection against oxidative stress. To understand this effect, we studied the antioxidant enzymes and reported a lower or equivalent level of mRNA for all enzymes in physioxia conditions compared to normoxia, but a higher activity for catalase and superoxide dismutases, whatever the culture model. The unchanged catalase amount, in NHEK and RHE, suggests an overactivation of the enzyme in physioxia, whereas the higher amount of SOD2 can explain the strong activity. Taken together, our results demonstrate the role of oxygen in the regulation of the antioxidant defences in keratinocytes, topic of particular importance for studying skin aging. Additionally, the present work points out the interest of the choice of both the keratinocyte culture model and the oxygen level to be as close as possible to the in situ skin.
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Affiliation(s)
- Nadira Chettouh-Hammas
- Center for Molecular Biophysics UPR4301 CNRS, Rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - Fabienne Fasani
- Center for Molecular Biophysics UPR4301 CNRS, Rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - Amandine Boileau
- Center for Molecular Biophysics UPR4301 CNRS, Rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - David Gosset
- Center for Molecular Biophysics UPR4301 CNRS, Rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - Giovanni Busco
- Center for Molecular Biophysics UPR4301 CNRS, Rue Charles Sadron, 45071 Orléans Cedex 2, France
| | - Catherine Grillon
- Center for Molecular Biophysics UPR4301 CNRS, Rue Charles Sadron, 45071 Orléans Cedex 2, France
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