1
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Phelan DE, Reddan B, Shigemura M, Sznajder JI, Crean D, Cummins EP. Orphan Nuclear Receptor Family 4A (NR4A) Members NR4A2 and NR4A3 Selectively Modulate Elements of the Monocyte Response to Buffered Hypercapnia. Int J Mol Sci 2024; 25:2852. [PMID: 38474099 PMCID: PMC10931687 DOI: 10.3390/ijms25052852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/19/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024] Open
Abstract
Hypercapnia occurs when the partial pressure of carbon dioxide (CO2) in the blood exceeds 45 mmHg. Hypercapnia is associated with several lung pathologies and is transcriptionally linked to suppression of immune and inflammatory signalling through poorly understood mechanisms. Here we propose Orphan Nuclear Receptor Family 4A (NR4A) family members NR4A2 and NR4A3 as potential transcriptional regulators of the cellular response to hypercapnia in monocytes. Using a THP-1 monocyte model, we investigated the sensitivity of NR4A family members to CO2 and the impact of depleting NR4A2 and NR4A3 on the monocyte response to buffered hypercapnia (10% CO2) using RNA-sequencing. We observed that NR4A2 and NR4A3 are CO2-sensitive transcription factors and that depletion of NR4A2 and NR4A3 led to reduced CO2-sensitivity of mitochondrial and heat shock protein (Hsp)-related genes, respectively. Several CO2-sensitive genes were, however, refractory to depletion of NR4A2 and NR4A3, indicating that NR4As regulate certain elements of the cellular response to buffered hypercapnia but that other transcription factors also contribute. Bioinformatic analysis of conserved CO2-sensitive genes implicated several novel putative CO2-sensitive transcription factors, of which the ETS Proto-Oncogene 1 Transcription Factor (ETS-1) was validated to show increased nuclear expression in buffered hypercapnia. These data give significant insights into the understanding of immune responses in patients experiencing hypercapnia.
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Affiliation(s)
- David E. Phelan
- School of Medicine, University College Dublin, Dublin 4, Ireland (B.R.)
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin 4, Ireland
| | - Ben Reddan
- School of Medicine, University College Dublin, Dublin 4, Ireland (B.R.)
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin 4, Ireland
| | - Masahiko Shigemura
- Division of Thoracic Surgery, Northwestern University, Chicago, IL 60611, USA;
| | - Jacob I. Sznajder
- Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA;
| | - Daniel Crean
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin 4, Ireland
- School of Veterinary Medicine, University College Dublin, Dublin 4, Ireland
| | - Eoin P. Cummins
- School of Medicine, University College Dublin, Dublin 4, Ireland (B.R.)
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin 4, Ireland
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2
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Phelan DE, Mota C, Strowitzki MJ, Shigemura M, Sznajder JI, Crowe L, Masterson JC, Hayes SE, Reddan B, Yin X, Brennan L, Crean D, Cummins EP. Hypercapnia alters mitochondrial gene expression and acylcarnitine production in monocytes. Immunol Cell Biol 2023. [PMID: 36967673 DOI: 10.1111/imcb.12642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 03/03/2023] [Accepted: 03/25/2023] [Indexed: 03/29/2023]
Abstract
CO2 is produced during aerobic respiration. Normally, levels of CO2 in the blood are tightly regulated but pCO2 can rise (hypercapnia, pCO2 > 45 mmHg) in patients with lung diseases, for example, chronic obstructive pulmonary disease (COPD). Hypercapnia is a risk factor in COPD but may be of benefit in the context of destructive inflammation. The effects of CO2 per se, on transcription, independent of pH change are poorly understood and warrant further investigation. Here we elucidate the influence of hypercapnia on monocytes and macrophages through integration of state-of-the-art RNA-sequencing, metabolic and metabolomic approaches. THP-1 monocytes and interleukin 4-polarized primary murine macrophages were exposed to 5% CO2 versus 10% CO2 for up to 24 h in pH-buffered conditions. In hypercapnia, we identified around 370 differentially expressed genes (DEGs) under basal and about 1889 DEGs under lipopolysaccharide-stimulated conditions in monocytes. Transcripts relating to both mitochondrial and nuclear-encoded gene expression were enhanced in hypercapnia in basal and lipopolysaccharide-stimulated cells. Mitochondrial DNA content was not enhanced, but acylcarnitine species and genes associated with fatty acid metabolism were increased in hypercapnia. Primary macrophages exposed to hypercapnia also increased activation of genes associated with fatty acid metabolism and reduced activation of genes associated with glycolysis. Thus, hypercapnia elicits metabolic shifts in lipid metabolism in monocytes and macrophages under pH-buffered conditions. These data indicate that CO2 is an important modulator of monocyte transcription that can influence immunometabolic signaling in immune cells in hypercapnia. These immunometabolic insights may be of benefit in the treatment of patients experiencing hypercapnia.
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Affiliation(s)
- David E Phelan
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Catarina Mota
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Moritz J Strowitzki
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Masahiko Shigemura
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Louise Crowe
- Allergy, Inflammation & Remodeling Research Laboratory, Kathleen Lonsdale Institute for Human Health Research, Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
| | - Joanne C Masterson
- Allergy, Inflammation & Remodeling Research Laboratory, Kathleen Lonsdale Institute for Human Health Research, Department of Biology, Maynooth University, Maynooth, County Kildare, Ireland
| | - Sophie E Hayes
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Ben Reddan
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Xiaofei Yin
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Lorraine Brennan
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Daniel Crean
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Eoin P Cummins
- School of Medicine, University College Dublin, Dublin, Ireland
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
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3
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Cummins EP, Bharat A, Sznajder JI, Vadász I. Editorial: Elevated Carbon Dioxide Sensing and Physiologic Effects. Front Physiol 2022; 13:894222. [PMID: 35574468 PMCID: PMC9092065 DOI: 10.3389/fphys.2022.894222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 03/22/2022] [Indexed: 11/21/2022] Open
Affiliation(s)
- Eoin P Cummins
- School of Medicine and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Ankit Bharat
- Division of Thoracic Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.,Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - István Vadász
- Department of Internal Medicine, Member of the German Center for Lung Research (DZL), Justus Liebig University, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany.,The Cardio-Pulmonary Institute (CPI), Giessen, Germany.,Institute for Lung Health (ILH), Giessen, Germany
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4
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Strowitzki MJ, Nelson R, Garcia MP, Tuffs C, Bleul MB, Fitzsimons S, Navas J, Uzieliene I, Ritter AS, Phelan D, Kierans SJ, Blanco A, Bernotiene E, Belton O, Schneider M, Cummins EP, Taylor CT. Carbon Dioxide Sensing by Immune Cells Occurs through Carbonic Anhydrase 2-Dependent Changes in Intracellular pH. J Immunol 2022; 208:2363-2375. [PMID: 35477686 DOI: 10.4049/jimmunol.2100665] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 03/09/2022] [Indexed: 06/14/2023]
Abstract
CO2, the primary gaseous product of respiration, is a major physiologic gas, the biology of which is poorly understood. Elevated CO2 is a feature of the microenvironment in multiple inflammatory diseases that suppresses immune cell activity. However, little is known about the CO2-sensing mechanisms and downstream pathways involved. We found that elevated CO2 correlates with reduced monocyte and macrophage migration in patients undergoing gastrointestinal surgery and that elevated CO2 reduces migration in vitro. Mechanistically, CO2 reduces autocrine inflammatory gene expression, thereby inhibiting macrophage activation in a manner dependent on decreased intracellular pH. Pharmacologic or genetic inhibition of carbonic anhydrases (CAs) uncouples a CO2-elicited intracellular pH response and attenuates CO2 sensitivity in immune cells. Conversely, CRISPR-driven upregulation of the isoenzyme CA2 confers CO2 sensitivity in nonimmune cells. Of interest, we found that patients with chronic lung diseases associated with elevated systemic CO2 (hypercapnia) display a greater risk of developing anastomotic leakage following gastrointestinal surgery, indicating impaired wound healing. Furthermore, low intraoperative pH levels in these patients correlate with reduced intestinal macrophage infiltration. In conclusion, CO2 is an immunomodulatory gas sensed by immune cells through a CA2-coupled change in intracellular pH.
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Affiliation(s)
- Moritz J Strowitzki
- School of Medicine, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
- Department of General, Visceral and Transplantation Surgery, Heidelberg University, Heidelberg, Germany
| | - Ross Nelson
- School of Medicine, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - Mario P Garcia
- School of Medicine, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - Christopher Tuffs
- Department of General, Visceral and Transplantation Surgery, Heidelberg University, Heidelberg, Germany
| | - Marc B Bleul
- Department of General, Visceral and Transplantation Surgery, Heidelberg University, Heidelberg, Germany
| | - Stephen Fitzsimons
- Diabetes Complications Research Centre, School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland; and
| | - Javier Navas
- School of Medicine, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - Ilona Uzieliene
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Alina S Ritter
- Department of General, Visceral and Transplantation Surgery, Heidelberg University, Heidelberg, Germany
| | - David Phelan
- School of Medicine, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - Sarah J Kierans
- School of Medicine, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - Alfonso Blanco
- School of Medicine, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - Eiva Bernotiene
- Department of Regenerative Medicine, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Orina Belton
- Diabetes Complications Research Centre, School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin, Ireland; and
| | - Martin Schneider
- Department of General, Visceral and Transplantation Surgery, Heidelberg University, Heidelberg, Germany
| | - Eoin P Cummins
- School of Medicine, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland
| | - Cormac T Taylor
- School of Medicine, Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, Ireland;
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5
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Phelan DE, Shigemura M, Aldhafiri S, Mota C, Hall TJ, Sznajder JI, Murphy EP, Crean D, Cummins EP. Transcriptional Profiling of Monocytes Deficient in Nuclear Orphan Receptors NR4A2 and NR4A3 Reveals Distinct Signalling Roles Related to Antigen Presentation and Viral Response. Front Immunol 2021; 12:676644. [PMID: 34248958 PMCID: PMC8267906 DOI: 10.3389/fimmu.2021.676644] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 06/07/2021] [Indexed: 11/22/2022] Open
Abstract
The nuclear receptor sub-family 4 group A (NR4A) family are early response genes that encode proteins that are activated in several tissues/cells in response to a variety of stressors. The NR4A family comprises NR4A1, NR4A2 and NR4A3 of which NR4A2 and NR4A3 are under researched and less understood, particularly in the context of immune cells. NR4A expression is associated with multiple diseases e.g. arthritis and atherosclerosis and the development of NR4A-targetting molecules as therapeutics is a current focus in this research field. Here, we use a combination of RNA-sequencing coupled with strategic bioinformatic analysis to investigate the down-stream effects of NR4A2 and NR4A3 in monocytes and dissect their common and distinct signalling roles. Our data reveals that NR4A2 and NR4A3 depletion has a robust and broad-reaching effect on transcription in both the unstimulated state and in the presence of LPS. Interestingly, many of the genes affected were present in both the unstimulated and stimulated states revealing a previously unappreciated role for the NR4As in unstimulated cells. Strategic clustering and bioinformatic analysis identified both distinct and common transcriptional roles for NR4A2 and NR4A3 in monocytes. NR4A2 notably was linked by both bioinformatic clustering analysis and transcription factor interactome analysis to pathways associated with antigen presentation and regulation of MHC genes. NR4A3 in contrast was more closely linked to pathways associated with viral response. Functional studies further support our data analysis pointing towards preferential/selective roles for NR4A2 in the regulation of antigen processing with common roles for NR4A2 and NR4A3 evident with respect to cell migration. Taken together this study provides novel mechanistic insights into the role of the enigmatic nuclear receptors NR4A2 and NR4A3 in monocytes.
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Affiliation(s)
- David E Phelan
- School of Medicine, University College Dublin, Dublin, Ireland.,Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Masahiko Shigemura
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Sarah Aldhafiri
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland.,Animal Genomics Laboratory, School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Catarina Mota
- School of Medicine, University College Dublin, Dublin, Ireland.,Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Thomas J Hall
- School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Evelyn P Murphy
- School of Medicine, University of Limerick, Limerick, Ireland
| | - Daniel Crean
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland.,Animal Genomics Laboratory, School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Eoin P Cummins
- School of Medicine, University College Dublin, Dublin, Ireland.,Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
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6
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Giffney HE, Cummins EP, Murphy EP, Brayden DJ, Crean D. Protein kinase D, ubiquitin and proteasome pathways are involved in adenosine receptor-stimulated NR4A expression in myeloid cells. Biochem Biophys Res Commun 2021; 555:19-25. [PMID: 33812054 DOI: 10.1016/j.bbrc.2021.03.082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/10/2021] [Accepted: 03/15/2021] [Indexed: 01/12/2023]
Abstract
Adenosine is a purine nucleoside pivotal for homeostasis in cells and tissues. Stimulation of the adenosine receptors (AR) has been shown to regulate the nuclear orphan receptor 4A (NR4A1-3) family, resulting in attenuation of hyper-inflammatory responses in myeloid cells. The NR4A1-3 orphan receptors are early immediate response genes and transcriptional regulators of cell and tissue homeostasis. The signal transduction and transcriptional mechanism(s) of how AR-stimulation promotes NR4A expression in myeloid cells is unknown and is the focus of this study. We confirm that adenosine and the stable analogue, 5'-N-Ethylcarboxamidoadenosine (NECA), enhance NR4A1-3 expression in THP-1 cells. Pharmacological approaches identified that protein kinase D (PKD) mediates AR-stimulated NR4A expression in myeloid cells and reveals no involvement of PKA nor PKC. The role of NF-κB, a principal regulator of NR4A expression in myeloid cells, was examined as a possible transcriptional regulator downstream of PKD. Utilising BAY11-7082 and MG-132, inhibitors of the respective ubiquitin and proteasome pathways essential for NF-κB activation, suggested a prospective role for NF-κB, or more specifically signalling via IKKα/β. However, biological interventional studies using overexpression of IκBα in myeloid cells and MEF cells lacking IKKα and IKKβ (IKKα/β-/-) revealed the NF-κB pathway is not utilised in mediating AR-stimulated NR4A expression. Thus, this study contributes mechanistic insight into how AR signalling modulates the expression of NR4A receptors, pivotal regulators of inflammatory responses in myeloid cells.
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Affiliation(s)
- Hugh E Giffney
- School of Veterinary Medicine, University College Dublin, Ireland; UCD Conway Institute, University College Dublin, Ireland
| | - Eoin P Cummins
- UCD Conway Institute, University College Dublin, Ireland; UCD School of Medicine, University College Dublin, Ireland
| | | | - David J Brayden
- School of Veterinary Medicine, University College Dublin, Ireland; UCD Conway Institute, University College Dublin, Ireland
| | - Daniel Crean
- School of Veterinary Medicine, University College Dublin, Ireland; UCD Conway Institute, University College Dublin, Ireland.
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7
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Ismaiel M, Murphy B, Aldhafiri S, Giffney HE, Thornton K, Mukhopadhya A, Keogh CE, Fattah S, Mohan HM, Cummins EP, Murphy EP, Winter DC, Crean D. The NR4A agonist, Cytosporone B, attenuates pro-inflammatory mediators in human colorectal cancer tissue ex vivo. Biochem Biophys Res Commun 2021; 554:179-185. [PMID: 33798945 DOI: 10.1016/j.bbrc.2021.03.110] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 03/19/2021] [Indexed: 12/17/2022]
Abstract
Inflammation is a pivotal pathological factor in colorectal cancer (CRC) initiation and progression, and modulating this inflammatory state has the potential to ameliorate disease progression. NR4A receptors have emerged as key regulators of inflammatory pathways that are important in CRC. Here, we have examined the effect of NR4A agonist, Cytosporone B (CsnB), on colorectal tissue integrity and its effect on the inflammatory profile in CRC tissue ex vivo. Here, we demonstrate concentrations up 100 μM CsnB did not adversely affect tissue integrity as measured using transepithelial electrical resistance, histology and crypt height. Subsequently, we reveal through the use of a cytokine/chemokine array, ELISA and qRT-PCR analysis that multiple pro-inflammatory mediators were significantly increased in CRC tissue compared to control tissue, which were then attenuated with the addition of CsnB (such as IL-1β, IL-8 and TNFα). Lastly, stratification of the data revealed that CsnB especially alters the inflammatory profile of tumours derived from males who had not undergone chemoradiotherapy. Thus, this study demonstrates that NR4A agonist CsnB does not adversely affect colon tissue structure or functionality and can attenuate the pro-inflammatory state of human CRC tissue ex vivo.
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Affiliation(s)
- Mohamed Ismaiel
- School of Medicine, University College Dublin, Dublin, Ireland; Department of Surgery, St. Vincent's University Hospital, Dublin, Ireland
| | - Brenda Murphy
- School of Medicine, University College Dublin, Dublin, Ireland; Department of Surgery, St. Vincent's University Hospital, Dublin, Ireland
| | - Sarah Aldhafiri
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Hugh E Giffney
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Kevin Thornton
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | | | - Ciara E Keogh
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Sarinj Fattah
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Helen M Mohan
- Department of Surgery, St. Vincent's University Hospital, Dublin, Ireland
| | - Eoin P Cummins
- School of Medicine, University College Dublin, Dublin, Ireland; Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Evelyn P Murphy
- School of Medicine, University of Limerick, Limerick, Ireland
| | - Des C Winter
- School of Medicine, University College Dublin, Dublin, Ireland; Department of Surgery, St. Vincent's University Hospital, Dublin, Ireland.
| | - Daniel Crean
- School of Veterinary Medicine, University College Dublin, Dublin, Ireland; Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland.
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8
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Adeeb F, Dorris ER, Morgan NE, Lawless D, Maqsood A, Ng WL, Killeen O, Cummins EP, Taylor CT, Savic S, Wilson AG, Fraser A. A Novel RELA Truncating Mutation in a Familial Behçet's Disease-like Mucocutaneous Ulcerative Condition. Arthritis Rheumatol 2021; 73:490-497. [PMID: 32969189 DOI: 10.1002/art.41531] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 09/10/2020] [Indexed: 12/26/2022]
Abstract
OBJECTIVE Monogenic Behçet's disease (BD)-like conditions are increasingly recognized and to date have been found to predominantly involve loss-of-function variants in TNFAIP3. This study was undertaken to identify genetic and pathobiologic mechanisms associated with a BD-like mucocutaneous ulcerative syndrome and neuromyelitis optica (NMO) occurring in 3 generations of an Irish family (n = 5 cases and 5 familial controls). METHODS Whole-exome sequencing was used to identify potential pathogenic variants in affected family members and determine segregation between affected and unaffected individuals. Relative v-rel reticuloendotheliosis viral oncogene homolog A (RELA) expression in peripheral blood mononuclear cells was compared by Western blotting. Human epithelial and RelA-/- mouse fibroblast experimental systems were used to determine the molecular impact of the RELA truncation in response to tumor necrosis factor (TNF). NF-κB signaling, transcriptional activation, apoptosis, and cytokine production were compared between wild-type and truncated RELA in experimental systems and patient samples. RESULTS A heterozygous cytosine deletion at position c.1459 in RELA was detected in affected family members. This mutation resulted in a frameshift p.His487ThrfsTer7, producing a truncated protein disrupting 2 transactivation domains. The truncated RELA protein lacks a full transactivation domain. The RELA protein variants were expressed at equal levels in peripheral mononuclear cells. RelA-/- mouse embryonic fibroblasts (MEFs) expressing recombinant human RELAp.His487ThrfsTer7 were compared to those expressing wild-type RELA; however, there was no difference in RELA nuclear translocation. In RelA-/- MEFs, expression of RELAp.His487ThrfsTer7 resulted in a 1.98-fold higher ratio of cleaved caspase 3 to caspase 3 induced by TNF compared to wild-type RELA (P = 0.036). CONCLUSION Our data indicate that RELA loss-of-function mutations cause BD-like autoinflammation and NMO via impaired NF-κB signaling and increased apoptosis.
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Affiliation(s)
- Fahd Adeeb
- University Hospital Limerick, Limerick, Ireland
| | | | - Niamh E Morgan
- University College Dublin, National Children's Research Centre, and Our Lady's Children's Hospital Crumlin, Dublin, Ireland
| | - Dylan Lawless
- NIHR Leeds Institute of Rheumatic and Musculoskeletal Medicine and St James's University Hospital, Leeds, UK
| | | | - Wan Lin Ng
- University Hospital Limerick, Limerick, Ireland
| | - Orla Killeen
- National Children's Research Centre and Our Lady's Children's Hospital Crumlin, Dublin, Ireland
| | | | | | - Sinisa Savic
- NIHR Leeds Institute of Rheumatic and Musculoskeletal Medicine and St James's University Hospital, Leeds, UK
| | | | - Alexander Fraser
- University Hospital Limerick and University of Limerick School of Medicine, Limerick, Ireland
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9
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Ryan S, Cummins EP, Farre R, Gileles-Hillel A, Jun JC, Oster H, Pepin JL, Ray DW, Reutrakul S, Sanchez-de-la-Torre M, Tamisier R, Almendros I. Understanding the pathophysiological mechanisms of cardiometabolic complications in obstructive sleep apnoea: towards personalised treatment approaches. Eur Respir J 2020; 56:13993003.02295-2019. [PMID: 32265303 DOI: 10.1183/13993003.02295-2019] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/15/2020] [Indexed: 12/19/2022]
Abstract
In January 2019, a European Respiratory Society research seminar entitled "Targeting the detrimental effects of sleep disturbances and disorders" was held in Dublin, Ireland. It provided the opportunity to critically review the current evidence of pathophysiological responses of sleep disturbances, such as sleep deprivation, sleep fragmentation or circadian misalignment and of abnormalities in physiological gases such as oxygen and carbon dioxide, which occur frequently in respiratory conditions during sleep. A specific emphasis of the seminar was placed on the evaluation of the current state of knowledge of the pathophysiology of cardiovascular and metabolic diseases in obstructive sleep apnoea (OSA). Identification of the detailed mechanisms of these processes is of major importance to the field and this seminar offered an ideal platform to exchange knowledge, and to discuss pitfalls of current models and the design of future collaborative studies. In addition, we debated the limitations of current treatment strategies for cardiometabolic complications in OSA and discussed potentially valuable alternative approaches.
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Affiliation(s)
- Silke Ryan
- Pulmonary and Sleep Disorders Unit, St Vincent's University Hospital, Dublin, Ireland .,School of Medicine, Conway Institute, University College Dublin, Dublin, Ireland
| | - Eoin P Cummins
- School of Medicine, Conway Institute, University College Dublin, Dublin, Ireland
| | - Ramon Farre
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona-IDIBAPS, and CIBER Enfermedades Respiratorias, Barcelona, Spain
| | - Alex Gileles-Hillel
- Pediatric Pulmonology and Sleep Unit, Dept of Pediatrics, and The Wohl Institute for Translational Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Jonathan C Jun
- Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Henrik Oster
- Institute of Neurobiology, University of Lübeck, Lübeck, Germany
| | | | - David W Ray
- NIHR Oxford Biomedical Research Centre, John Radcliffe Hospital, Oxford, UK.,Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, UK
| | - Sirimon Reutrakul
- Division of Endocrinology, Diabetes, and Metabolism, Dept of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Manuel Sanchez-de-la-Torre
- Group of Precision Medicine in Chronic Diseases, Hospital Arnau de Vilanova-Santa Maria, IRBLleida, Lleida, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Renaud Tamisier
- HP2 INSERM U1042, Université Grenoble Alpes, Grenoble, France
| | - Isaac Almendros
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona-IDIBAPS, and CIBER Enfermedades Respiratorias, Barcelona, Spain
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10
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Abstract
Molecular oxygen (O2) and carbon dioxide (CO2) are the primary gaseous substrate and product of oxidative phosphorylation in respiring organisms, respectively. Variance in the levels of either of these gasses outside of the physiological range presents a serious threat to cell, tissue, and organism survival. Therefore, it is essential that endogenous levels are monitored and kept at appropriate concentrations to maintain a state of homeostasis. Higher organisms such as mammals have evolved mechanisms to sense O2 and CO2 both in the circulation and in individual cells and elicit appropriate corrective responses to promote adaptation to commonly encountered conditions such as hypoxia and hypercapnia. These can be acute and transient nontranscriptional responses, which typically occur at the level of whole animal physiology or more sustained transcriptional responses, which promote chronic adaptation. In this review, we discuss the mechanisms by which mammals sense changes in O2 and CO2 and elicit adaptive responses to maintain homeostasis. We also discuss crosstalk between these pathways and how they may represent targets for therapeutic intervention in a range of pathological states.
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Affiliation(s)
- Eoin P Cummins
- UCD Conway Institute, Systems Biology Ireland and the School of Medicine, University College Dublin, Belfield, Dublin, Ireland
| | - Moritz J Strowitzki
- UCD Conway Institute, Systems Biology Ireland and the School of Medicine, University College Dublin, Belfield, Dublin, Ireland
| | - Cormac T Taylor
- UCD Conway Institute, Systems Biology Ireland and the School of Medicine, University College Dublin, Belfield, Dublin, Ireland
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11
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Strowitzki MJ, Cummins EP, Taylor CT. Protein Hydroxylation by Hypoxia-Inducible Factor (HIF) Hydroxylases: Unique or Ubiquitous? Cells 2019; 8:cells8050384. [PMID: 31035491 PMCID: PMC6562979 DOI: 10.3390/cells8050384] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/24/2019] [Accepted: 04/24/2019] [Indexed: 02/07/2023] Open
Abstract
All metazoans that utilize molecular oxygen (O2) for metabolic purposes have the capacity to adapt to hypoxia, the condition that arises when O2 demand exceeds supply. This is mediated through activation of the hypoxia-inducible factor (HIF) pathway. At physiological oxygen levels (normoxia), HIF-prolyl hydroxylases (PHDs) hydroxylate proline residues on HIF-α subunits leading to their destabilization by promoting ubiquitination by the von-Hippel Lindau (VHL) ubiquitin ligase and subsequent proteasomal degradation. HIF-α transactivation is also repressed in an O2-dependent way due to asparaginyl hydroxylation by the factor-inhibiting HIF (FIH). In hypoxia, the O2-dependent hydroxylation of HIF-α subunits by PHDs and FIH is reduced, resulting in HIF-α accumulation, dimerization with HIF-β and migration into the nucleus to induce an adaptive transcriptional response. Although HIFs are the canonical substrates for PHD- and FIH-mediated protein hydroxylation, increasing evidence indicates that these hydroxylases may also have alternative targets. In addition to PHD-conferred alterations in protein stability, there is now evidence that hydroxylation can affect protein activity and protein/protein interactions for alternative substrates. PHDs can be pharmacologically inhibited by a new class of drugs termed prolyl hydroxylase inhibitors which have recently been approved for the treatment of anemia associated with chronic kidney disease. The identification of alternative targets of HIF hydroxylases is important in order to fully elucidate the pharmacology of hydroxylase inhibitors (PHI). Despite significant technical advances, screening, detection and verification of alternative functional targets for PHDs and FIH remain challenging. In this review, we discuss recently proposed non-HIF targets for PHDs and FIH and provide an overview of the techniques used to identify these.
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Affiliation(s)
- Moritz J Strowitzki
- UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Eoin P Cummins
- UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Cormac T Taylor
- UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
- Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland.
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12
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Phelan DP, Crean D, Cummins EP. Modulation of Nuclear Receptor Family 4A (NR4A) Expression by CO
2. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.792.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- David P. Phelan
- School of MedicineUniversity College DublinDublinIreland
- Conway Institute of Biomolecular and Biomedical ResearchUniversity College DublinDublinIreland
| | - Daniel Crean
- Conway Institute of Biomolecular and Biomedical ResearchUniversity College DublinDublinIreland
- School of Veterinary ScienceUniversity College DublinDublinIreland
| | - Eoin P. Cummins
- School of MedicineUniversity College DublinDublinIreland
- Conway Institute of Biomolecular and Biomedical ResearchUniversity College DublinDublinIreland
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13
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Crifo B, Schaible B, Brown E, Halligan DN, Scholz CC, Fitzpatrick SF, Kirwan A, Roche HM, Criscuoli M, Naldini A, Giffney H, Crean D, Blanco A, Cavadas MA, Cummins EP, Fabian Z, Taylor CT. Hydroxylase Inhibition Selectively Induces Cell Death in Monocytes. J I 2019; 202:1521-1530. [DOI: 10.4049/jimmunol.1800912] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 12/19/2018] [Indexed: 12/21/2022]
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14
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Affiliation(s)
- Eoin P Cummins
- School of Medicine and Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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15
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Keogh CE, Scholz CC, Rodriguez J, Selfridge AC, Kreigsheim A, Cummins EP. Mechanisms of CO
2
‐dependent regulation of NFκB signaling. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.864.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ciara E. Keogh
- School of Medicine University College DublinDublinIreland
| | - Carsten C. Scholz
- School of Medicine University College DublinDublinIreland
- Institute of PhysiologyUniversity of ZürichZürichSwitzerland
| | - Javier Rodriguez
- Edinburgh Cancer Research CentreEdinburghUnited Kingdom
- Systems Biology IrelandUniversity College DublinDublin 4Ireland
| | | | - Alex Kreigsheim
- Edinburgh Cancer Research CentreEdinburghUnited Kingdom
- Systems Biology IrelandUniversity College DublinDublin 4Ireland
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16
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Keogh CE, Scholz CC, Rodriguez J, Selfridge AC, von Kriegsheim A, Cummins EP. Carbon dioxide-dependent regulation of NF-κB family members RelB and p100 gives molecular insight into CO 2-dependent immune regulation. J Biol Chem 2017; 292:11561-11571. [PMID: 28507099 DOI: 10.1074/jbc.m116.755090] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 05/12/2017] [Indexed: 12/31/2022] Open
Abstract
CO2 is a physiological gas normally produced in the body during aerobic respiration. Hypercapnia (elevated blood pCO2 >≈50 mm Hg) is a feature of several lung pathologies, e.g. chronic obstructive pulmonary disease. Hypercapnia is associated with increased susceptibility to bacterial infections and suppression of inflammatory signaling. The NF-κB pathway has been implicated in these effects; however, the molecular mechanisms underpinning cellular sensitivity of the NF-κB pathway to CO2 are not fully elucidated. Here, we identify several novel CO2-dependent changes in the NF-κB pathway. NF-κB family members p100 and RelB translocate to the nucleus in response to CO2 A cohort of RelB protein-protein interactions (e.g. with Raf-1 and IκBα) are altered by CO2 exposure, although others are maintained (e.g. with p100). RelB is processed by CO2 in a manner dependent on a key C-terminal domain located in its transactivation domain. Loss of the RelB transactivation domain alters NF-κB-dependent transcriptional activity, and loss of p100 alters sensitivity of RelB to CO2 Thus, we provide molecular insight into the CO2 sensitivity of the NF-κB pathway and implicate altered RelB/p100-dependent signaling in the CO2-dependent regulation of inflammatory signaling.
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Affiliation(s)
- Ciara E Keogh
- From the School of Medicine and Conway Institute and
| | - Carsten C Scholz
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland.,the Institute of Physiology, University of Zürich, CH-8057 Zürich, Switzerland
| | - Javier Rodriguez
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland.,the Edinburgh Cancer Research Centre, Edinburgh EH4 2XR, Scotland, United Kingdom, and
| | | | - Alexander von Kriegsheim
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland.,the Edinburgh Cancer Research Centre, Edinburgh EH4 2XR, Scotland, United Kingdom, and
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17
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McEvoy C, de Gaetano M, Giffney HE, Bahar B, Cummins EP, Brennan EP, Barry M, Belton O, Godson CG, Murphy EP, Crean D. NR4A Receptors Differentially Regulate NF-κB Signaling in Myeloid Cells. Front Immunol 2017; 8:7. [PMID: 28167941 PMCID: PMC5256039 DOI: 10.3389/fimmu.2017.00007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 01/03/2017] [Indexed: 12/19/2022] Open
Abstract
Dysregulation of inflammatory responses is a hallmark of multiple diseases such as atherosclerosis and rheumatoid arthritis. As constitutively active transcription factors, NR4A nuclear receptors function to control the magnitude of inflammatory responses and in chronic inflammatory disease can be protective or pathogenic. Within this study, we demonstrate that TLR4 stimulation using the endotoxin lipopolysaccharide (LPS) rapidly enhances NR4A1–3 expression in human and murine, primary and immortalized myeloid cells with concomitant gene transcription and protein secretion of MIP-3α, a central chemokine implicated in numerous pathologies. Deficiency of NR4A2 and NR4A3 in human and murine myeloid cells reveals that both receptors function as positive regulators of enhanced MIP-3α expression. In contrast, within the same cell types and conditions, altered NR4A activity leads to suppression of LPS-induced MCP-1 gene and protein expression. An equivalent pattern of inflammatory gene regulation is replicated in TNFα-treated myeloid cells. We show that NF-κB is the critical regulator of NR4A1–3, MIP-3α, and MCP-1 during TLR4 stimulation in myeloid cells and highlight a parallel mechanism whereby NR4A activity can repress or enhance NF-κB target gene expression simultaneously. Mechanistic insight reveals that NR4A2 does not require DNA-binding capacity in order to enhance or repress NF-κB target gene expression simultaneously and establishes a role for NF-κB family member Relb as a novel NR4A target gene involved in the positive regulation of MIP-3α. Thus, our data reveal a dynamic role for NR4A receptors concurrently enhancing and repressing NF-κB activity in myeloid cells leading to altered transcription of key inflammatory mediators.
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Affiliation(s)
- Caitriona McEvoy
- School of Medicine, University College Dublin, Dublin, Ireland; Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland; Diabetes and Complications Research Centre, Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Monica de Gaetano
- School of Medicine, University College Dublin, Dublin, Ireland; Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland; Diabetes and Complications Research Centre, Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Hugh E Giffney
- Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland; School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Bojlul Bahar
- International Institute of Nutritional Sciences and Applied Food Safety Studies, University of Central Lancashire , Preston , UK
| | - Eoin P Cummins
- School of Medicine, University College Dublin, Dublin, Ireland; Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Eoin P Brennan
- School of Medicine, University College Dublin, Dublin, Ireland; Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland; Diabetes and Complications Research Centre, Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Mary Barry
- St. Vincent's University Hospital , Dublin , Ireland
| | - Orina Belton
- Diabetes and Complications Research Centre, Conway Institute for Biomolecular and Biomedical Science, University College Dublin , Dublin , Ireland
| | - Catherine G Godson
- School of Medicine, University College Dublin, Dublin, Ireland; Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland; Diabetes and Complications Research Centre, Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Evelyn P Murphy
- Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland; School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Daniel Crean
- Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland; Diabetes and Complications Research Centre, Conway Institute for Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland; School of Veterinary Medicine, University College Dublin, Dublin, Ireland
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18
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Manresa MC, Tambuwala MM, Radhakrishnan P, Harnoss JM, Brown E, Cavadas MA, Keogh CE, Cheong A, Barrett KE, Cummins EP, Schneider M, Taylor CT. Hydroxylase inhibition regulates inflammation-induced intestinal fibrosis through the suppression of ERK-mediated TGF-β1 signaling. [corrected]. Am J Physiol Gastrointest Liver Physiol 2016; 311:G1076-G1090. [PMID: 27789456 DOI: 10.1152/ajpgi.00229.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 10/09/2016] [Indexed: 01/31/2023]
Abstract
Fibrosis is a complication of chronic inflammatory disorders such as inflammatory bowel disease, a condition which has limited therapeutic options and often requires surgical intervention. Pharmacologic inhibition of oxygen-sensing prolyl hydroxylases, which confer oxygen sensitivity upon the hypoxia-inducible factor pathway, has recently been shown to have therapeutic potential in colitis, although the mechanisms involved remain unclear. Here, we investigated the impact of hydroxylase inhibition on inflammation-driven fibrosis in a murine colitis model. Mice exposed to dextran sodium sulfate, followed by a period of recovery, developed intestinal fibrosis characterized by alterations in the pattern of collagen deposition and infiltration of activated fibroblasts. Treatment with the hydroxylase inhibitor dimethyloxalylglycine ameliorated fibrosis. TGF-β1 is a key regulator of fibrosis that acts through the activation of fibroblasts. Hydroxylase inhibition reduced TGF-β1-induced expression of fibrotic markers in cultured fibroblasts, suggesting a direct role for hydroxylases in TGF-β1 signaling. This was at least in part due to inhibition of noncanonical activation of extracellular signal-regulated kinase (ERK) signaling. In summary, pharmacologic hydroxylase inhibition ameliorates intestinal fibrosis through suppression of TGF-β1-dependent ERK activation in fibroblasts. We hypothesize that in addition to previously reported immunosupressive effects, hydroxylase inhibitors independently suppress profibrotic pathways.
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Affiliation(s)
- Mario C Manresa
- School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland.,School of Medicine and Medical Science, Charles Institute of Dermatology, University College Dublin, Dublin, Ireland
| | - Murtaza M Tambuwala
- School of Pharmacy and Pharmaceutical Science, Ulster University, Coleraine, Northerm Ireland
| | - Praveen Radhakrishnan
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Jonathan M Harnoss
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Eric Brown
- School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Miguel A Cavadas
- School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland.,Systems Biology Ireland, University College Dublin, Dublin, Ireland; and
| | - Ciara E Keogh
- School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Alex Cheong
- School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland.,Systems Biology Ireland, University College Dublin, Dublin, Ireland; and
| | - Kim E Barrett
- Department of Medicine and Biomedical Sciences Ph.D. Program, University of California, San Diego, School of Medicine, La Jolla, California
| | - Eoin P Cummins
- School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Martin Schneider
- Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Cormac T Taylor
- School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland; .,Systems Biology Ireland, University College Dublin, Dublin, Ireland; and
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19
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Cavadas MAS, Mesnieres M, Crifo B, Manresa MC, Selfridge AC, Keogh CE, Fabian Z, Scholz CC, Nolan KA, Rocha LMA, Tambuwala MM, Brown S, Wdowicz A, Corbett D, Murphy KJ, Godson C, Cummins EP, Taylor CT, Cheong A. REST is a hypoxia-responsive transcriptional repressor. Sci Rep 2016; 6:31355. [PMID: 27531581 PMCID: PMC4987654 DOI: 10.1038/srep31355] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 07/18/2016] [Indexed: 12/15/2022] Open
Abstract
Cellular exposure to hypoxia results in altered gene expression in a range of physiologic and pathophysiologic states. Discrete cohorts of genes can be either up- or down-regulated in response to hypoxia. While the Hypoxia-Inducible Factor (HIF) is the primary driver of hypoxia-induced adaptive gene expression, less is known about the signalling mechanisms regulating hypoxia-dependent gene repression. Using RNA-seq, we demonstrate that equivalent numbers of genes are induced and repressed in human embryonic kidney (HEK293) cells. We demonstrate that nuclear localization of the Repressor Element 1-Silencing Transcription factor (REST) is induced in hypoxia and that REST is responsible for regulating approximately 20% of the hypoxia-repressed genes. Using chromatin immunoprecipitation assays we demonstrate that REST-dependent gene repression is at least in part mediated by direct binding to the promoters of target genes. Based on these data, we propose that REST is a key mediator of gene repression in hypoxia.
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Affiliation(s)
- Miguel A S Cavadas
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland.,Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland.,Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 2780-156 Oeiras, Portugal
| | - Marion Mesnieres
- Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland
| | - Bianca Crifo
- Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland
| | - Mario C Manresa
- Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland
| | - Andrew C Selfridge
- Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland
| | - Ciara E Keogh
- Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland
| | - Zsolt Fabian
- Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland
| | - Carsten C Scholz
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland.,Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland.,Institute of Physiology and Zurich Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Karen A Nolan
- Institute of Physiology and Zurich Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.,Diabetes Complications Research Centre, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland
| | - Liliane M A Rocha
- Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Murtaza M Tambuwala
- School of Pharmacy and Pharmaceutical Sciences, University of Ulster, Coleraine, Co. Londonderry, BT52 1SA, Northern Ireland, UK
| | - Stuart Brown
- Center for Health Informatics and Bioinformatics, New York University School of Medicine, New York, NY 10016, USA
| | - Anita Wdowicz
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Danielle Corbett
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Keith J Murphy
- Neurotherapeutics Research Group, UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Catherine Godson
- Diabetes Complications Research Centre, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland
| | - Eoin P Cummins
- Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland
| | - Cormac T Taylor
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland.,Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland
| | - Alex Cheong
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland.,Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Sciences, University College Dublin, Dublin 4, Ireland.,Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK
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20
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Cummins EP, Keogh CE. Respiratory gases and the regulation of transcription. Exp Physiol 2016; 101:986-1002. [DOI: 10.1113/ep085715] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 05/23/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Eoin P. Cummins
- School of Medicine; University College Dublin; Belfield 4 Dublin Ireland
| | - Ciara E. Keogh
- School of Medicine; University College Dublin; Belfield 4 Dublin Ireland
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21
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Abstract
Uncontrolled inflammation underpins a diverse range of diseases where effective therapy remains an unmet clinical need. Hypoxia is a prominent feature of the inflammatory microenvironment that regulates key transcription factors including HIF and NF-κB in both innate and adaptive immune cells. In turn, altered activity of the pathways controlled by these factors can affect the course of inflammation through the regulation of immune cell development and function. In this review, we will discuss these pathways and the oxygen sensors that confer hypoxic sensitivity in immune cells. Furthermore, we will describe how hypoxia-dependent pathways contribute to immunity and discuss their potential as therapeutic targets in inflammatory and infectious disease.
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22
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Fitzpatrick SF, Fábián Z, Schaible B, Lenihan CR, Schwarzl T, Rodriguez J, Zheng X, Li Z, Tambuwala MM, Higgins DG, O'Meara Y, Slattery C, Manresa MC, Fraisl P, Bruning U, Baes M, Carmeliet P, Doherty G, von Kriegsheim A, Cummins EP, Taylor CT. Prolyl hydroxylase-1 regulates hepatocyte apoptosis in an NF-κB-dependent manner. Biochem Biophys Res Commun 2016; 474:579-586. [DOI: 10.1016/j.bbrc.2016.04.085] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 04/18/2016] [Indexed: 01/21/2023]
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23
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Beaton H, Andrews D, Parsons M, Murphy M, Gaffney A, Kavanagh D, McKay GJ, Maxwell AP, Taylor CT, Cummins EP, Godson C, Higgins DF, Murphy P, Crean J. Wnt6 regulates epithelial cell differentiation and is dysregulated in renal fibrosis. Am J Physiol Renal Physiol 2016; 311:F35-45. [PMID: 27122540 DOI: 10.1152/ajprenal.00136.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 04/22/2016] [Indexed: 02/07/2023] Open
Abstract
Diabetic nephropathy is the most common microvascular complication of diabetes mellitus, manifesting as mesangial expansion, glomerular basement membrane thickening, glomerular sclerosis, and progressive tubulointerstitial fibrosis leading to end-stage renal disease. Here we describe the functional characterization of Wnt6, whose expression is progressively lost in diabetic nephropathy and animal models of acute tubular injury and renal fibrosis. We have shown prominent Wnt6 and frizzled 7 (FzD7) expression in the mesonephros of the developing mouse kidney, suggesting a role for Wnt6 in epithelialization. Importantly, TCF/Lef reporter activity is also prominent in the mesonephros. Analysis of Wnt family members in human renal biopsies identified differential expression of Wnt6, correlating with severity of the disease. In animal models of tubular injury and fibrosis, loss of Wnt6 was evident. Wnt6 signals through the canonical pathway in renal epithelial cells as evidenced by increased phosphorylation of GSK3β (Ser9), nuclear accumulation of β-catenin and increased TCF/Lef transcriptional activity. FzD7 was identified as a putative receptor of Wnt6. In vitro Wnt6 expression leads to de novo tubulogenesis in renal epithelial cells grown in three-dimensional culture. Importantly, Wnt6 rescued epithelial cell dedifferentiation in response to transforming growth factor-β (TGF-β); Wnt6 reversed TGF-β-mediated increases in vimentin and loss of epithelial phenotype. Wnt6 inhibited TGF-β-mediated p65-NF-κB nuclear translocation, highlighting cross talk between the two pathways. The critical role of NF-κB in the regulation of vimentin expression was confirmed in both p65(-/-) and IKKα/β(-/-) embryonic fibroblasts. We propose that Wnt6 is involved in epithelialization and loss of Wnt6 expression contributes to the pathogenesis of renal fibrosis.
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Affiliation(s)
- Hayley Beaton
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, UCD School of Biomolecular and Biomedical Science, Belfield, Dublin, Ireland
| | - Darrell Andrews
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, UCD School of Biomolecular and Biomedical Science, Belfield, Dublin, Ireland
| | - Martin Parsons
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, UCD School of Biomolecular and Biomedical Science, Belfield, Dublin, Ireland
| | - Mary Murphy
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, UCD School of Biomolecular and Biomedical Science, Belfield, Dublin, Ireland
| | - Andrew Gaffney
- UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland
| | - David Kavanagh
- Nephrology Research Group, Centre for Public Health, Queens University Belfast, Royal Victoria Hospital, Belfast, United Kingdom; and
| | - Gareth J McKay
- Nephrology Research Group, Centre for Public Health, Queens University Belfast, Royal Victoria Hospital, Belfast, United Kingdom; and
| | - Alexander P Maxwell
- Nephrology Research Group, Centre for Public Health, Queens University Belfast, Royal Victoria Hospital, Belfast, United Kingdom; and
| | - Cormac T Taylor
- UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland
| | - Eoin P Cummins
- UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland
| | - Catherine Godson
- UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland
| | - Debra F Higgins
- UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin, Ireland
| | - Paula Murphy
- Zoology Department, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - John Crean
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, UCD School of Biomolecular and Biomedical Science, Belfield, Dublin, Ireland;
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24
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Selfridge AC, Cavadas MAS, Scholz CC, Campbell EL, Welch LC, Lecuona E, Colgan SP, Barrett KE, Sporn PHS, Sznajder JI, Cummins EP, Taylor CT. Hypercapnia Suppresses the HIF-dependent Adaptive Response to Hypoxia. J Biol Chem 2016; 291:11800-8. [PMID: 27044749 DOI: 10.1074/jbc.m116.713941] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Indexed: 01/18/2023] Open
Abstract
Molecular oxygen and carbon dioxide are the primary gaseous substrate and product of oxidative metabolism, respectively. Hypoxia (low oxygen) and hypercapnia (high carbon dioxide) are co-incidental features of the tissue microenvironment in a range of pathophysiologic states, including acute and chronic respiratory diseases. The hypoxia-inducible factor (HIF) is the master regulator of the transcriptional response to hypoxia; however, little is known about the impact of hypercapnia on gene transcription. Because of the relationship between hypoxia and hypercapnia, we investigated the effect of hypercapnia on the HIF pathway. Hypercapnia suppressed HIF-α protein stability and HIF target gene expression both in mice and cultured cells in a manner that was at least in part independent of the canonical O2-dependent HIF degradation pathway. The suppressive effects of hypercapnia on HIF-α protein stability could be mimicked by reducing intracellular pH at a constant level of partial pressure of CO2 Bafilomycin A1, a specific inhibitor of vacuolar-type H(+)-ATPase that blocks lysosomal degradation, prevented the hypercapnic suppression of HIF-α protein. Based on these results, we hypothesize that hypercapnia counter-regulates activation of the HIF pathway by reducing intracellular pH and promoting lysosomal degradation of HIF-α subunits. Therefore, hypercapnia may play a key role in the pathophysiology of diseases where HIF is implicated.
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Affiliation(s)
| | - Miguel A S Cavadas
- Conway Institute, and Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland
| | - Carsten C Scholz
- From the School of Medicine and Medical Science, Conway Institute, and Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland, the Institute of Physiology, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Eric L Campbell
- the University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Lynn C Welch
- the Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, and
| | - Emilia Lecuona
- the Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, and
| | - Sean P Colgan
- the University of Colorado Denver, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Kim E Barrett
- From the School of Medicine and Medical Science, Conway Institute, and
| | - Peter H S Sporn
- the Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, and the Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60612
| | - Jacob I Sznajder
- the Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, and
| | - Eoin P Cummins
- From the School of Medicine and Medical Science, Conway Institute, and
| | - Cormac T Taylor
- From the School of Medicine and Medical Science, Conway Institute, and Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland,
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Abstract
Uncontrolled or non-resolving inflammation underpins a range of disease states including rheumatoid arthritis, inflammatory bowel disease and atherosclerosis. Hypoxia is a prominent feature of chronically inflamed tissues. This is due to elevated oxygen consumption by highly metabolically active inflamed resident cells and activated infiltrating immunocytes, as well as diminished oxygen supply due to vascular dysfunction. Tissue hypoxia can have a significant impact upon inflammatory signaling pathways in immune and non-immune cells and this can impact upon disease progression. In this review, we will discuss the relationship between tissue hypoxia and inflammation and identify how hypoxia-sensitive signaling pathways are potential therapeutic targets in chronic inflammatory disease.
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Affiliation(s)
- Eoin P Cummins
- School of Medicine and Medical Science & The Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Ciara E Keogh
- School of Medicine and Medical Science & The Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Daniel Crean
- School of Medicine and Medical Science & The Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Cormac T Taylor
- School of Medicine and Medical Science & The Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
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Tambuwala MM, Manresa MC, Cummins EP, Aversa V, Coulter IS, Taylor CT. Targeted delivery of the hydroxylase inhibitor DMOG provides enhanced efficacy with reduced systemic exposure in a murine model of colitis. J Control Release 2015; 217:221-7. [DOI: 10.1016/j.jconrel.2015.09.022] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/11/2015] [Accepted: 09/12/2015] [Indexed: 12/30/2022]
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Nguyen LK, Cavadas MAS, Scholz CC, Fitzpatrick SF, Bruning U, Cummins EP, Tambuwala MM, Manresa MC, Kholodenko BN, Taylor CT, Cheong A. A dynamic model of the hypoxia-inducible factor 1a (HIF-1a) network. J Cell Sci 2015; 128:422. [PMID: 25589793 DOI: 10.1242/jcs.167304] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Crean D, Cummins EP, Bahar B, Mohan H, McMorrow JP, Murphy EP. Adenosine Modulates NR4A Orphan Nuclear Receptors To Attenuate Hyperinflammatory Responses in Monocytic Cells. J Immunol 2015; 195:1436-48. [PMID: 26150530 DOI: 10.4049/jimmunol.1402039] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 06/02/2015] [Indexed: 02/02/2023]
Abstract
Adenosine receptor-mediated regulation of monocyte/macrophage inflammatory responses is critical in the maintenance of tissue homeostasis. In this study, we reveal that adenosine potently modulates the expression of NR4A1, 2, and 3 orphan nuclear receptors in myeloid cells, and this modulation is primarily through the adenosine A2a receptor subtype. We demonstrate that A2a receptor activation of NR4A1-3 receptor synthesis is further enhanced in TLR4-stimulated monocytes. After TLR4 stimulation, NR4A receptor-depleted monocyte/macrophage cells display significantly altered expression of cell-surface markers and produce increased inflammatory cytokine and chemokine secretion rendering the cells an enhanced proinflammatory phenotype. Exposure of TLR4 or TNF-α-stimulated monocytes to adenosine analogs directs changes in the expression of MIP-3α and IL-23p19, with NR4A2 depletion leading to significantly enhanced expression of these factors. Furthermore, we establish that nuclear levels of NF-κB/p65 are increased in TLR/adenosine-stimulated NR4A2-depleted cells. We show that, after TLR/adenosine receptor stimulation, NR4A2 depletion promotes significant binding of NF-κB/p65 to a κB consensus binding motif within the MIP-3α proximal promoter leading to increased protein secretion, confirming a pivotal role for NF-κB activity in controlling cellular responses and gene expression outcomes in response to these mediators. Thus, these data demonstrate that during an inflammatory response, adenosine modulation of NR4A receptor activity acts to limit NF-κB-mediated effects and that loss of NR4A2 expression leads to enhanced NF-κB activity and hyperinflammatory responses in myeloid cells.
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Affiliation(s)
- Daniel Crean
- UCD Veterinary Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland; and Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Eoin P Cummins
- Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Bojlul Bahar
- UCD Veterinary Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland; and
| | - Helen Mohan
- UCD Veterinary Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland; and
| | - Jason P McMorrow
- UCD Veterinary Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland; and
| | - Evelyn P Murphy
- UCD Veterinary Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland; and Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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Cummins EP, Selfridge AC, Sporn PH, Sznajder JI, Taylor CT. Carbon dioxide-sensing in organisms and its implications for human disease. Cell Mol Life Sci 2013; 71:831-45. [PMID: 24045706 DOI: 10.1007/s00018-013-1470-6] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 08/22/2013] [Accepted: 08/30/2013] [Indexed: 12/29/2022]
Abstract
The capacity of organisms to sense changes in the levels of internal and external gases and to respond accordingly is central to a range of physiologic and pathophysiologic processes. Carbon dioxide, a primary product of oxidative metabolism is one such gas that can be sensed by both prokaryotic and eukaryotic cells and in response to altered levels, elicit the activation of multiple adaptive pathways. The outcomes of activating CO2-sensitive pathways in various species include increased virulence of fungal and bacterial pathogens, prey-seeking behavior in insects as well as taste perception, lung function, and the control of immunity in mammals. In this review, we discuss what is known about the mechanisms underpinning CO2 sensing across a range of species and consider the implications of this for physiology, disease progression, and the possibility of developing new therapeutics for inflammatory and infectious disease.
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Affiliation(s)
- Eoin P Cummins
- School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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Scholz CC, Kriegsheim A, Tambuwala MM, Hams E, Cheong A, Bruning U, Fallon PG, Cummins EP, Taylor CT. Prolyl Hydroxylase 1 (PHD1) and Factor Inhibiting HIF (FIH) regulate IL‐1β‐induced NF‐κB activity linking key hypoxic and inflammatory signaling pathways. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.717.9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | - Alex Cheong
- Systems Biology IrelandUniversity College DublinDublinIreland
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Nguyen LK, Cavadas MAS, Scholz CC, Fitzpatrick SF, Bruning U, Cummins EP, Tambuwala MM, Manresa MC, Kholodenko BN, Taylor CT, Cheong A. A dynamic model of the hypoxia-inducible factor 1α (HIF-1α) network. J Cell Sci 2013; 126:1454-63. [PMID: 23390316 DOI: 10.1242/jcs.119974] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Activation of the hypoxia-inducible factor (HIF) pathway is a critical step in the transcriptional response to hypoxia. Although many of the key proteins involved have been characterised, the dynamics of their interactions in generating this response remain unclear. In the present study, we have generated a comprehensive mathematical model of the HIF-1α pathway based on core validated components and dynamic experimental data, and confirm the previously described connections within the predicted network topology. Our model confirms previous work demonstrating that the steps leading to optimal HIF-1α transcriptional activity require sequential inhibition of both prolyl- and asparaginyl-hydroxylases. We predict from our model (and confirm experimentally) that there is residual activity of the asparaginyl-hydroxylase FIH (factor inhibiting HIF) at low oxygen tension. Furthermore, silencing FIH under conditions where prolyl-hydroxylases are inhibited results in increased HIF-1α transcriptional activity, but paradoxically decreases HIF-1α stability. Using a core module of the HIF network and mathematical proof supported by experimental data, we propose that asparaginyl hydroxylation confers a degree of resistance upon HIF-1α to proteosomal degradation. Thus, through in vitro experimental data and in silico predictions, we provide a comprehensive model of the dynamic regulation of HIF-1α transcriptional activity by hydroxylases and use its predictive and adaptive properties to explain counter-intuitive biological observations.
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Affiliation(s)
- Lan K Nguyen
- Systems Biology Ireland, University College Dublin, Dublin 4, Ireland
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32
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Abstract
Human embryonic stem cells (hESCs) have been reported to confer cytoprotection in the context of tissue injury. This is somewhat counterintuitive given that microenvironmental factors such as hypoxia and oxidative stress may activate p53 and result in death and differentiation of these hESCs. In this article, we discuss a novel mechanism through which hESCs can be re-programmed (through exposure to hypoxia/oxidative stress) to transiently suppress p53, enhance 'stemness', and exist in a highly cytoprotective and undifferentiated state.
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Oliver KM, Lenihan CR, Bruning U, Cheong A, Laffey JG, McLoughlin P, Taylor CT, Cummins EP. Hypercapnia induces cleavage and nuclear localization of RelB protein, giving insight into CO2 sensing and signaling. J Biol Chem 2012; 287:14004-11. [PMID: 22396550 PMCID: PMC3340129 DOI: 10.1074/jbc.m112.347971] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Carbon dioxide (CO2) is increasingly being appreciated as an intracellular signaling molecule that affects inflammatory and immune responses. Elevated arterial CO2 (hypercapnia) is encountered in a range of clinical conditions, including chronic obstructive pulmonary disease, and as a consequence of therapeutic ventilation in acute respiratory distress syndrome. In patients suffering from this syndrome, therapeutic hypoventilation strategy designed to reduce mechanical damage to the lungs is accompanied by systemic hypercapnia and associated acidosis, which are associated with improved patient outcome. However, the molecular mechanisms underlying the beneficial effects of hypercapnia and the relative contribution of elevated CO2 or associated acidosis to this response remain poorly understood. Recently, a role for the non-canonical NF-κB pathway has been postulated to be important in signaling the cellular transcriptional response to CO2. In this study, we demonstrate that in cells exposed to elevated CO2, the NF-κB family member RelB was cleaved to a lower molecular weight form and translocated to the nucleus in both mouse embryonic fibroblasts and human pulmonary epithelial cells (A549). Furthermore, elevated nuclear RelB was observed in vivo and correlated with hypercapnia-induced protection against LPS-induced lung injury. Hypercapnia-induced RelB processing was sensitive to proteasomal inhibition by MG-132 but was independent of the activity of glycogen synthase kinase 3β or MALT-1, both of which have been previously shown to mediate RelB processing. Taken together, these data demonstrate that RelB is a CO2-sensitive NF-κB family member that may contribute to the beneficial effects of hypercapnia in inflammatory diseases of the lung.
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Affiliation(s)
- Kathryn M Oliver
- School of Medicine and Medical Science, UCD Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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Cahill E, Costello CM, Rowan SC, Harkin S, Howell K, Leonard MO, Southwood M, Cummins EP, Fitzpatrick SF, Taylor CT, Morrell NW, Martin F, McLoughlin P. Gremlin plays a key role in the pathogenesis of pulmonary hypertension. Circulation 2012; 125:920-30. [PMID: 22247494 DOI: 10.1161/circulationaha.111.038125] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Pulmonary hypertension occurs in chronic hypoxic lung diseases, significantly worsening morbidity and mortality. The important role of altered bone morphogenetic protein (BMP) signaling in pulmonary hypertension was first suspected after the identification of heterozygous BMP receptor mutations as the underlying defect in the rare heritable form of pulmonary arterial hypertension. Subsequently, it was demonstrated that BMP signaling was also reduced in common forms of pulmonary hypertension, including hypoxic pulmonary hypertension; however, the mechanism of this reduction has not previously been elucidated. METHODS AND RESULTS Expression of 2 BMP antagonists, gremlin 1 and gremlin 2, was higher in the lung than in other organs, and gremlin 1 was further increased in the walls of small intrapulmonary vessels of mice during the development of hypoxic pulmonary hypertension. Hypoxia stimulated gremlin secretion from human pulmonary microvascular endothelial cells in vitro, which inhibited endothelial BMP signaling and BMP-stimulated endothelial repair. Haplodeficiency of gremlin 1 augmented BMP signaling in the hypoxic mouse lung and reduced pulmonary vascular resistance by attenuating vascular remodeling. Furthermore, gremlin was increased in the walls of small intrapulmonary vessels in idiopathic pulmonary arterial hypertension and the rare heritable form of pulmonary arterial hypertension in a distribution suggesting endothelial localization. CONCLUSIONS These findings demonstrate a central role for increased gremlin in hypoxia-induced pulmonary vascular remodeling and the increased pulmonary vascular resistance in hypoxic pulmonary hypertension. High levels of basal gremlin expression in the lung may account for the unique vulnerability of the pulmonary circulation to heterozygous mutations of BMP type 2 receptor in pulmonary arterial hypertension.
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Affiliation(s)
- Edwina Cahill
- University College Dublin, School of Medicine and Medical Sciences, Belfield, Dublin 4, Ireland
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Abstract
Carbon dioxide (CO(2)) is a physiological gas found at low levels in the atmosphere and produced in cells during the process of aerobic respiration. Consequently, the levels of CO(2) within tissues are usually significantly higher than those found externally. Shifts in tissue levels of CO(2) (leading to either hypercapnia or hypocapnia) are associated with a number of pathophysiological conditions in humans and can occur naturally in niche habitats such as those of burrowing animals. Clinical studies have indicated that such altered CO(2) levels can impact upon disease progression. Recent advances in our understanding of the biology of CO(2) has shown that like other physiological gases such as molecular oxygen (O(2)) and nitric oxide (NO), CO(2) levels can be sensed by cells resulting in the initiation of physiological and pathophysiological responses. Acute CO(2) sensing in neurons and peripheral and central chemoreceptors is important in rapidly activated responses including olfactory signalling, taste sensation and cardiorespiratory control. Furthermore, a role for CO(2) in the regulation of gene transcription has recently been identified with exposure of cells and model organisms to high CO(2) leading to suppression of genes involved in the regulation of innate immunity and inflammation. This latter, transcriptional regulatory role for CO(2), has been largely attributed to altered activity of the NF-B family of transcription factors. Here, we review our evolving understanding of how CO(2) impacts upon gene transcription.
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Affiliation(s)
- Cormac T Taylor
- UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
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Fitzpatrick SF, Tambuwala MM, Bruning U, Schaible B, Scholz CC, Byrne A, O'Connor A, Gallagher WM, Lenihan CR, Garvey JF, Howell K, Fallon PG, Cummins EP, Taylor CT. An intact canonical NF-κB pathway is required for inflammatory gene expression in response to hypoxia. J Immunol 2010; 186:1091-6. [PMID: 21149600 DOI: 10.4049/jimmunol.1002256] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hypoxia is a feature of the microenvironment in a number of chronic inflammatory conditions due to increased metabolic activity and disrupted perfusion at the inflamed site. Hypoxia contributes to inflammation through the regulation of gene expression via key oxygen-sensitive transcriptional regulators including the hypoxia-inducible factor (HIF) and NF-κB. Recent studies have revealed a high degree of interdependence between HIF and NF-κB signaling; however, the relative contribution of each to hypoxia-induced inflammatory gene expression remains unclear. In this study, we use transgenic mice expressing luciferase under the control of NF-κB to demonstrate that hypoxia activates NF-κB in the heart and lungs of mice in vivo. Using small interfering RNA targeted to the p65 subunit of NF-κB, we confirm a unidirectional dependence of hypoxic HIF-1α accumulation upon an intact canonical NF-κB pathway in cultured cells. Cyclooxygenase-2 and other key proinflammatory genes are transcriptionally induced by hypoxia in a manner that is both HIF-1 and NF-κB dependent, and in mouse embryonic fibroblasts lacking an intact canonical NF-κB pathway, there is a loss of hypoxia-induced inflammatory gene expression. Finally, under conditions of hypoxia, HIF-1α and the p65 subunit of NF-κB directly bind to the cyclooxygenase-2 promoter. These results implicate an essential role for NF-κB signaling in inflammatory gene expression in response to hypoxia both through the regulation of HIF-1 and through direct effects upon target gene expression.
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Affiliation(s)
- Susan F Fitzpatrick
- UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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Agbor TA, Cheong A, Comerford KM, Scholz CC, Bruning U, Clarke A, Cummins EP, Cagney G, Taylor CT. Small ubiquitin-related modifier (SUMO)-1 promotes glycolysis in hypoxia. J Biol Chem 2010; 286:4718-26. [PMID: 21123177 DOI: 10.1074/jbc.m110.115931] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Under conditions of hypoxia, most eukaryotic cells undergo a shift in metabolic strategy, which involves increased flux through the glycolytic pathway. Although this is critical for bioenergetic homeostasis, the underlying mechanisms have remained incompletely understood. Here, we report that the induction of hypoxia-induced glycolysis is retained in cells when gene transcription or protein synthesis are inhibited suggesting the involvement of additional post-translational mechanisms. Post-translational protein modification by the small ubiquitin related modifier-1 (SUMO-1) is induced in hypoxia and mass spectrometric analysis using yeast cells expressing tap-tagged Smt3 (the yeast homolog of mammalian SUMO) revealed hypoxia-dependent modification of a number of key glycolytic enzymes. Overexpression of SUMO-1 in mammalian cancer cells resulted in increased hypoxia-induced glycolysis and resistance to hypoxia-dependent ATP depletion. Supporting this, non-transformed cells also demonstrated increased glucose uptake upon SUMO-1 overexpression. Conversely, cells overexpressing the de-SUMOylating enzyme SENP-2 failed to demonstrate hypoxia-induced glycolysis. SUMO-1 overexpressing cells demonstrated focal clustering of glycolytic enzymes in response to hypoxia leading us to hypothesize a role for SUMOylation in promoting spatial re-organization of the glycolytic pathway. In summary, we hypothesize that SUMO modification of key metabolic enzymes plays an important role in shifting cellular metabolic strategies toward increased flux through the glycolytic pathway during periods of hypoxic stress.
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Affiliation(s)
- Terence A Agbor
- UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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Tambuwala MM, Cummins EP, Lenihan CR, Kiss J, Stauch M, Scholz CC, Fraisl P, Lasitschka F, Mollenhauer M, Saunders SP, Maxwell PH, Carmeliet P, Fallon PG, Schneider M, Taylor CT. Loss of prolyl hydroxylase-1 protects against colitis through reduced epithelial cell apoptosis and increased barrier function. Gastroenterology 2010; 139:2093-101. [PMID: 20600011 DOI: 10.1053/j.gastro.2010.06.068] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 05/27/2010] [Accepted: 06/21/2010] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS Hypoxia inducible factor (HIF) prolyl hydroxylase inhibitors are protective in mouse models of inflammatory bowel disease (IBD). Here, we investigated the therapeutic target(s) and mechanism(s) involved. METHODS The effect of genetic deletion of individual HIF-prolyl hydroxylase (PHD) enzymes on the development of dextran sulphate sodium (DSS)-induced colitis was examined in mice. RESULTS PHD1(-/-), but not PHD2(+/-) or PHD3(-/-), mice were less susceptible to the development of colitis than wild-type controls as determined by weight loss, disease activity, colon histology, neutrophil infiltration, and cytokine expression. Reduced susceptibility of PHD1(-/-) mice to colitis was associated with increased density of colonic epithelial cells relative to wild-type controls, which was because of decreased levels of apoptosis that resulted in enhanced epithelial barrier function. Furthermore, with the use of cultured epithelial cells it was confirmed that hydroxylase inhibition reversed DSS-induced apoptosis and barrier dysfunction. Finally, PHD1 levels were increased with disease severity in intestinal tissue from patients with IBD and in colonic tissues from DSS-treated mice. CONCLUSIONS These results imply a role for PHD1 as a positive regulator of intestinal epithelial cell apoptosis in the inflamed colon. Genetic loss of PHD1 is protective against colitis through decreased epithelial cell apoptosis and consequent enhancement of intestinal epithelial barrier function. Thus, targeted PHD1 inhibition may represent a new therapeutic approach in IBD.
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Cummins EP, Oliver KM, Lenihan CR, Fitzpatrick SF, Bruning U, Scholz CC, Slattery C, Leonard MO, McLoughlin P, Taylor CT. NF-κB Links CO2 Sensing to Innate Immunity and Inflammation in Mammalian Cells. J I 2010; 185:4439-45. [DOI: 10.4049/jimmunol.1000701] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Abstract
Hypoxia is a common physiologic and pathophysiologic stimulus that activates the expression of genes through oxygen-sensitive transcription factors including the hypoxia-inducible factor (HIF) and nuclear factor-kappaB (NF-kappaB). Hypoxia-dependent gene expression can have important physiologic or pathophysiologic consequences for an organism, depending upon the cause of the hypoxic insult. Consequently, this pathway represents an attractive therapeutic target in a number of disease states. While the mechanism linking hypoxia to the activation of HIF has been extensively studied, our understanding of how hypoxia activates NF-kappaB is limited. Recent studies have demonstrated that similar oxygen-sensing mechanisms are employed in conferring oxygen sensitivity to both HIF and NF-kappaB-dependent gene expression. Furthermore, there is an extensive degree of cross-talk occurring between NF-kappaB and HIF. Investigations into mechanisms of hypoxic activation of HIF and NF-kappaB and how these signaling pathways interact will uncover new therapeutic modalities in a diverse range of disease states where hypoxia is a feature of the microenvironment including cancer, vascular disease, and chronic inflammation.
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Affiliation(s)
- Cormac T Taylor
- UCD Conway Institute, School of Medicine and Medical Science, College of Life Science, University College Dublin, Belfield, Dublin, Ireland.
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Oliver KM, Garvey JF, Ng CT, Veale DJ, Fearon U, Cummins EP, Taylor CT. Hypoxia activates NF-kappaB-dependent gene expression through the canonical signaling pathway. Antioxid Redox Signal 2009; 11:2057-64. [PMID: 19422287 DOI: 10.1089/ars.2008.2400] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hypoxia and inflammation are coincidental events in a diverse range of disease states including tumor growth, ischemia, and chronic inflammation. Hypoxia contributes to the development of inflammation, at least in part through the activation and/or potentiation of NF-kappaB, a master regulator of genes involved in innate immunity, inflammation, and apoptosis. NF-kappaB can be activated through two distinct signaling pathways termed the canonical and noncanonical pathways, respectively. The canonical pathway is activated through the IKKalpha/beta/gamma complex, while the noncanonical pathway involves NIK-mediated activation of IKKalpha homodimers. In the current study, we have investigated the relative roles of these two pathways in hypoxia-dependent NF-kappaB activation. Lymphotoxin alpha1beta2 (LTalpha1beta2) activated both the canonical and noncanonical NF-kappaB signaling pathways in HeLa cells. Sustained hypoxia enhanced basal and LTalpha1beta2-induced NF-kappaB activity in a manner that was dependent upon the canonical but not the noncanonical signaling pathway. Intermittent hypoxia activated NF-kappaB in a manner that was also primarily dependent upon the canonical pathway. Knockdown of the p65 subunit of the canonical NF-kappaB pathway was sufficient to abolish the effects of hypoxia on LTalpha1beta2-induced NF-kappaB activity. Furthermore, in synovial biopsies obtained at arthroscopy from patients with active inflammatory arthritis, the canonical pathway was preferentially activated in those patents with lower joint pO2 values. In summary, we hypothesize that hypoxia enhances NF-kappaB activity primarily through affecting the canonical pathway.
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Affiliation(s)
- Kathryn M Oliver
- UCD Conway Institute, University College Dublin, Belfield, Ireland
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Abstract
NFκB is a master regulator of innate immunity and inflammatory signalling. Microenvironmental hypoxia has long been identified as being coincident with chronic inflammation. The contribution of microenvironmental hypoxia to NFκB-induced inflammation has more recently been appreciated. Identification of the co-regulation of NFκB and hypoxia inducible factor (HIF) pathways by 2-oxo-glutarate-dependent hydroxylase family members has highlighted an intimate relationship between NFκB inflammatory signalling and HIF-mediated hypoxic signalling pathways. Adding another layer of complexity to our understanding of the role of NFκB inflammatory signalling by hypoxia is the recent recognition of the contribution of basal NFκB activity to HIF-1α transcription. This observation implicates an important and previously unappreciated role for NFκB in inflammatory disease where HIF-1α is activated. The present review will discuss recent literature pertaining to the regulation of NFκB inflammatory signalling by hypoxia and some of the inflammatory diseases where this may play an important role. Furthermore, we will discuss the potential for prolylhydroxylase inhibitors in inflammatory disease.
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Affiliation(s)
- Kathryn M Oliver
- School of Medicine and Medical Science, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
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Cummins EP, Seeballuck F, Keely SJ, Mangan NE, Callanan JJ, Fallon PG, Taylor CT. The hydroxylase inhibitor dimethyloxalylglycine is protective in a murine model of colitis. Gastroenterology 2008; 134:156-65. [PMID: 18166353 DOI: 10.1053/j.gastro.2007.10.012] [Citation(s) in RCA: 325] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Accepted: 09/27/2007] [Indexed: 12/17/2022]
Abstract
BACKGROUND & AIMS Prolyl and asparaginyl hydroxylases are key oxygen-sensing enzymes that confer hypoxic sensitivity to transcriptional regulatory pathways including the hypoxia inducible factor 1 (HIF-1) and nuclear factor-kappaB (NF-kappaB). Knockout of either HIF-1 or (IKKbeta-dependent) NF-kappaB pathways in intestinal epithelial cells promotes inflammatory disease in murine models of colitis. Both HIF-1 and NF-kappaB pathways are repressed by the action of hydroxylases through the hydroxylation of key regulatory molecules. METHODS In this study we have investigated the effects of the hydroxylase inhibitor dimethyloxalylglycine (DMOG) on Caco-2 intestinal epithelial cells in vitro and in a dextran sodium sulfate-induced model of murine colitis. RESULTS DMOG induces both HIF-1 and NF-kappaB activity in cultured intestinal epithelial cells, and is profoundly protective in dextran-sodium sulfate colitis in a manner that is at least in part reflected by the development of an anti-apoptotic phenotype in intestinal epithelial cells, which we propose reduces epithelial barrier dysfunction. CONCLUSIONS These data show that hydroxylase inhibitors such as DMOG represent a new strategy for the treatment of inflammatory bowel disease.
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Affiliation(s)
- Eoin P Cummins
- UCD Conway Institute, University College Dublin, Belfield, Dublin, Ireland
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Barry RE, Allan BB, Cummins EP, Kattla JJ, Giblin A, Scally N, Taylor CT, Brazil DP. Enhanced sensitivity of protein kinase B/Akt to insulin in hypoxia is independent of HIF1α and promotes cell viability. Eur J Cell Biol 2007; 86:393-403. [PMID: 17544543 DOI: 10.1016/j.ejcb.2007.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Revised: 04/25/2007] [Accepted: 04/25/2007] [Indexed: 12/13/2022] Open
Abstract
Maintenance of oxygen homeostasis is a key requirement to ensure normal mammalian cell growth and differentiation. Hypoxia arises when oxygen demand exceeds supply, and is a feature of multiple human diseases including stroke, cancer and renal fibrosis. We have investigated the effect of hypoxia on kidney cells, and observed that insulin-induced cell viability is increased in hypoxia. We have characterized the role of protein kinase B (PKB/Akt) in these cells as a potential mediator of this effect. PKB/Akt activity was increased by low oxygen concentrations in kidney cells, and insulin-stimulated activation of PKB/Akt was stronger, more rapid and more sustained in hypoxia. Reduction of HIF1alpha levels using antimycin-A or siRNA targeting HIF1alpha did not affect PKB/Akt activation in hypoxia. Pharmacologic stabilization of HIF1alpha independent of hypoxia did not increase insulin-stimulated PKB/Akt activation. Although increased insulin-stimulated cell viability was observed in hypoxia, no differences in the degree of insulin-stimulated glucose uptake were observed in L6 muscle cells in hypoxia compared to normoxia. Thus, PKB/Akt may regulate specific cellular responses to growth factors such as insulin under adverse conditions such as hypoxia.
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Affiliation(s)
- Robert E Barry
- UCD School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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Abstract
Hypoxia and inflammation are coincidental events in an array of diseased tissues, including chronically inflamed sites (e.g., inflammatory bowel disease, rheumatoid arthritis), growing tumors, myocardial infarcts, atherosclerotic plaques, healing wounds, and sites of bacterial infection (Murdoch et al., 2005). An understanding of how hypoxia modulates the inflammatory response is critical in developing our fundamental understanding of inflammatory disease and identifying new windows of therapeutic opportunity. Nuclear factor-kappaB (NF-kappaB) is a master transcriptional regulator of inflammatory and antiapoptotic gene expression, the activation of which has significant implications in disease development. Recent work has uncovered mechanisms by which hypoxia modulates the activation of NF-kappaB in cells through decreased oxygen-dependent suppression of the key regulators of this pathway. This work has implicated a novel role for proline and asparagine hydroxylases in the modulation of NF-kappaB activity. Here, we describe methodologies used to demonstrate and interrogate hypoxic induction of the NF-kappaB pathway.
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Affiliation(s)
- Eoin P Cummins
- UCD Conway Institute, University College Dublin, Dublin, Ireland
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Cummins EP, Berra E, Comerford KM, Ginouves A, Fitzgerald KT, Seeballuck F, Godson C, Nielsen JE, Moynagh P, Pouyssegur J, Taylor CT. Prolyl hydroxylase-1 negatively regulates IkappaB kinase-beta, giving insight into hypoxia-induced NFkappaB activity. Proc Natl Acad Sci U S A 2006; 103:18154-9. [PMID: 17114296 PMCID: PMC1643842 DOI: 10.1073/pnas.0602235103] [Citation(s) in RCA: 597] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Hypoxia is a feature of the microenvironment of a growing tumor. The transcription factor NFkappaB is activated in hypoxia, an event that has significant implications for tumor progression. Here, we demonstrate that hypoxia activates NFkappaB through a pathway involving activation of IkappaB kinase-beta (IKKbeta) leading to phosphorylation-dependent degradation of IkappaBalpha and liberation of NFkappaB. Furthermore, through increasing the pool and/or activation potential of IKKbeta, hypoxia amplifies cellular sensitivity to stimulation with TNFalpha. Within its activation loop, IKKbeta contains an evolutionarily conserved LxxLAP consensus motif for hydroxylation by prolyl hydroxylases (PHDs). Mimicking hypoxia by treatment of cells with siRNA against PHD-1 or PHD-2 or the pan-prolyl hydroxylase inhibitor DMOG results in NFkappaB activation. Conversely, overexpression of PHD-1 decreases cytokine-stimulated NFkappaB reporter activity, further suggesting a repressive role for PHD-1 in controlling the activity of NFkappaB. Hypoxia increases both the expression and activity of IKKbeta, and site-directed mutagenesis of the proline residue (P191A) of the putative IKKbeta hydroxylation site results in a loss of hypoxic inducibility. Thus, we hypothesize that hypoxia releases repression of NFkappaB activity through decreased PHD-dependent hydroxylation of IKKbeta, an event that may contribute to tumor development and progression through amplification of tumorigenic signaling pathways.
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Affiliation(s)
- Eoin P. Cummins
- *Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland; and
| | - Edurne Berra
- Institute of Signaling, Developmental Biology, and Cancer Research, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6543, University of Nice, Centre Antoine Lacassagne, 33 Avenue Valombrose, 06189 Nice, France
| | - Katrina M. Comerford
- *Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland; and
| | - Amandine Ginouves
- Institute of Signaling, Developmental Biology, and Cancer Research, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6543, University of Nice, Centre Antoine Lacassagne, 33 Avenue Valombrose, 06189 Nice, France
| | - Kathleen T. Fitzgerald
- *Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland; and
| | - Fergal Seeballuck
- *Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland; and
| | - Catherine Godson
- *Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland; and
| | - Jens E. Nielsen
- *Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland; and
| | - Paul Moynagh
- *Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland; and
| | - Jacques Pouyssegur
- Institute of Signaling, Developmental Biology, and Cancer Research, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6543, University of Nice, Centre Antoine Lacassagne, 33 Avenue Valombrose, 06189 Nice, France
| | - Cormac T. Taylor
- *Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland; and
- To whom correspondence should be addressed at:
Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, College of Life Sciences, University College Dublin, Belfield, Dublin 4, Ireland. E-mail:
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Comerford KM, Leonard MO, Cummins EP, Fitzgerald KT, Beullens M, Bollen M, Taylor CT. Regulation of protein phosphatase 1gamma activity in hypoxia through increased interaction with NIPP1: implications for cellular metabolism. J Cell Physiol 2006; 209:211-8. [PMID: 16826568 DOI: 10.1002/jcp.20726] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Eukaryotic cells sense decreased oxygen levels and respond by altering their metabolic strategy to sustain non-respiratory ATP production through glycolysis, and thus promote cell survival in a hypoxic environment. Protein phosphatase 1 (PP1) has been recently implicated in the governance of the rational use of energy when metabolic substrates are abundant and contributes to cellular recovery following metabolic stress. Under conditions of hypoxia, the expression of the gamma isoform of PP1 (PP1gamma), is diminished, an event we have hypothesized to be involved in the adaptive cellular response to hypoxia. Decreased PP1gamma activity in hypoxia has a profound impact on the activity of the cAMP response element binding protein (CREB), a major transcriptional regulator of metabolic genes and processes. Here, we demonstrate a further mechanism leading to inhibition of PP1 activity in hypoxia which occurs at least in part through increased association with the nuclear inhibitor of PP1 (NIPP1), an event dependent upon decreased basal cAMP/PKA-dependent signaling. Using a dominant negative NIPP1 construct, we provide evidence that NIPP1 plays a major role in the regulation of both CREB protein expression and CREB-dependent transcription in hypoxia. Furthermore, we demonstrate functional sequellae of such events including altered gene expression and recovery of cellular ATP levels. In summary, we demonstrate that interaction with NIPP1 mediates decreased PP1gamma activity in hypoxia, an event which may constitute an inherent part of the cellular oxygen-sensing machinery and may play a role in physiologic adaptation to hypoxia.
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Affiliation(s)
- Kathrina M Comerford
- School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Ireland
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Abstract
Hypoxia is a common pathophysiological occurrence with a profound impact on the cellular transcriptome. The consequences of hypoxia-induced or hypoxia-repressed gene expression have important implications in disease processes as diverse as tumour development and chronic inflammation. While the hypoxia-inducible factor (HIF-1) plays a major role in controlling the ubiquitous transcriptional response to hypoxia, it is clear that a number of other transcription factors are also activated either directly or indirectly. In this review, we comprehensively discuss the transcription factors that have been reported to be hypoxia-responsive and the signalling mechanisms leading to their activation. Understanding such events will enhance our understanding of cellular oxygen sensing.
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Affiliation(s)
- Eoin P Cummins
- Department of Medicine and Therapeutics, The Conway Institute for Biomolecular and Biomedical Research and the Dublin Molecular Medicine Centre, University College Dublin, Belfield, Dublin, 4, Ireland
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Comerford KM, Cummins EP, Taylor CT. c-Jun NH2-Terminal Kinase Activation Contributes to Hypoxia-Inducible Factor 1α–Dependent P-Glycoprotein Expression in Hypoxia. Cancer Res 2004; 64:9057-61. [PMID: 15604272 DOI: 10.1158/0008-5472.can-04-1919] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We previously have shown that hypoxia increases the expression of P-glycoprotein, which in turn increases tumor cell capacity to actively extrude chemotherapeutic agents and may contribute to tumor drug resistance. This event is mediated through the hypoxia-inducible factor (HIF-1). Here, we investigated the role of the stress-activated protein kinase c-Jun NH(2)-terminal kinase (JNK) in the signaling mechanisms underlying these events. Hypoxia activates JNK activity in vitro and in vivo. Overexpression of mitogen-activated protein kinase (MAPK) kinase kinase (MEKK-1), which preferentially activates JNK, mimics, in a nonadditive way, hypoxia-induced activity of the MDR1 promoter and expression of MDR1 mRNA and P-glycoprotein. Furthermore, the JNK inhibitor SP600125 selectively and specifically inhibits hypoxia- and MEKK-1-induced MDR1 promoter activity in a dose-dependent manner. JNK inhibition also reversed hypoxia- and MEKK-1-induced activity of an HIF-1-dependent reporter gene. MEKK-1-induced MDR1 expression depends on a functional HIF-1 binding site (hypoxia-responsive element). Hypoxia- but not cobalt chloride-dependent HIF-1-DNA binding and transcriptional activation was inhibited by SP600125, indicating that hypoxia-induced signaling to HIF-1 depends on JNK activation. Because it has been reported that reactive oxygen species are increased in hypoxia and related to JNK activation, we investigated their role in signaling this response. Whereas exogenous addition of H(2)O(2) was sufficient to activate JNK, reactive oxygen species scavengers were without effect on hypoxia-induced JNK or HIF-1 activation. Thus, hypoxia-elicited MDR1 expression, which depends on HIF-1 activation, depends at least in part on signaling via activation of JNK. Furthermore, these events are independent of the generation of reactive oxygen intermediates. Thus, JNK may represent a therapeutic target in the prevention of tumor resistance to chemotherapeutic treatment.
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Affiliation(s)
- Katrina M Comerford
- Department of Medicine and Therapeutics, The Conway Institute for Biomolecular and Biomedical Research and the Dublin Molecular Medicine Centre, University College, Dublin, Ireland
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