101
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Nagaraj C, Tabeling C, Nagy BM, Jain PP, Marsh LM, Papp R, Pienn M, Witzenrath M, Ghanim B, Klepetko W, Weir EK, Heschl S, Kwapiszewska G, Olschewski A, Olschewski H. Hypoxic vascular response and ventilation/perfusion matching in end-stage COPD may depend on p22phox. Eur Respir J 2017; 50:50/1/1601651. [PMID: 28729471 DOI: 10.1183/13993003.01651-2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 04/10/2017] [Indexed: 11/05/2022]
Abstract
Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease in which the amount of emphysema and airway disease may be very different between individuals, even in end-stage disease. Emphysema formation may be linked to the involvement of the small pulmonary vessels. The NAPDH oxidase (Nox) family is emerging as a key disease-related factor in vascular diseases, but currently its role in hypoxia-induced pulmonary remodelling in COPD remains unclear.Here we investigate the role of p22phox, a regulatory subunit of Nox, in COPD lungs, hypoxic pulmonary vasoconstriction (HPV), hypoxia-induced pulmonary vascular remodelling and pulmonary hypertension.In COPD, compared to control lungs, p22phox expression was significantly reduced. The expression was correlated positively with mean pulmonary arterial pressure and oxygenation index and negatively with the diffusing capacity of the lung for carbon monoxide (p<0.02). This suggests a role of p22phox in ventilation/perfusion ratio matching, vascular remodelling and loss of perfused lung area. In p22phox-/- mice, HPV was significantly impaired. In the chronic hypoxic setting, lack of p22phox was associated with improved right ventricular function and decreased pulmonary vascular remodelling.p22phox-dependent Nox plays an important role in the COPD phenotype, by its action on phase II HPV and chronic vascular remodelling.
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Affiliation(s)
- Chandran Nagaraj
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria.,Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Christoph Tabeling
- Dept of Infectious Diseases and Pulmonary Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Bence M Nagy
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria.,Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Pritesh P Jain
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - Leigh M Marsh
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - Rita Papp
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - Michael Pienn
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - Martin Witzenrath
- Dept of Infectious Diseases and Pulmonary Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Bahil Ghanim
- Dept of Thoracic Surgery, Division of Surgery, Medical University Vienna, Vienna, Austria
| | - Walter Klepetko
- Dept of Thoracic Surgery, Division of Surgery, Medical University Vienna, Vienna, Austria
| | - E Kenneth Weir
- Dept of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Stefan Heschl
- Dept of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Graz, Austria
| | - Grazyna Kwapiszewska
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria.,Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Andrea Olschewski
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria .,Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Horst Olschewski
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria.,Division of Pulmonology, Dept of Internal Medicine, Medical University of Graz, Graz, Austria
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102
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Graham AM, Presnell JS. Hypoxia Inducible Factor (HIF) transcription factor family expansion, diversification, divergence and selection in eukaryotes. PLoS One 2017; 12:e0179545. [PMID: 28614393 PMCID: PMC5470732 DOI: 10.1371/journal.pone.0179545] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 05/31/2017] [Indexed: 01/01/2023] Open
Abstract
Hypoxia inducible factor (HIF) transcription factors are crucial for regulating a variety of cellular activities in response to oxygen stress (hypoxia). In this study, we determine the evolutionary history of HIF genes and their associated transactivation domains, as well as perform selection and functional divergence analyses across their four characteristic domains. Here we show that the HIF genes are restricted to metazoans: At least one HIF-α homolog is found within the genomes of non-bilaterians and bilaterian invertebrates, while most vertebrate genomes contain between two and six HIF-α genes. We also find widespread purifying selection across all four characteristic domain types, bHLH, PAS, NTAD, CTAD, in HIF-α genes, and evidence for Type I functional divergence between HIF-1α, HIF-2α /EPAS, and invertebrate HIF genes. Overall, we describe the evolutionary histories of the HIF transcription factor gene family and its associated transactivation domains in eukaryotes. We show that the NTAD and CTAD domains appear de novo, without any appearance outside of the HIF-α subunits. Although they both appear in invertebrates as well as vertebrate HIF- α sequences, there seems to have been a substantial loss across invertebrates or were convergently acquired in these few lineages. We reaffirm that HIF-1α is phylogenetically conserved among most metazoans, whereas HIF-2α appeared later. Overall, our findings can be attributed to the substantial integration of this transcription factor family into the critical tasks associated with maintenance of oxygen homeostasis and vascularization, particularly in the vertebrate lineage.
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Affiliation(s)
- Allie M. Graham
- Department of Biology, University of Miami, Coral Gables, Florida, United States of America
- * E-mail:
| | - Jason S. Presnell
- Department of Biology, University of Miami, Coral Gables, Florida, United States of America
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103
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Gao L, González-Rodríguez P, Ortega-Sáenz P, López-Barneo J. Redox signaling in acute oxygen sensing. Redox Biol 2017; 12:908-915. [PMID: 28476010 PMCID: PMC5426049 DOI: 10.1016/j.redox.2017.04.033] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/24/2017] [Accepted: 04/24/2017] [Indexed: 11/22/2022] Open
Abstract
Acute oxygen (O2) sensing is essential for individuals to survive under hypoxic conditions. The carotid body (CB) is the main peripheral chemoreceptor, which contains excitable and O2-sensitive glomus cells with O2-regulated ion channels. Upon exposure to acute hypoxia, inhibition of K+ channels is the signal that triggers cell depolarization, transmitter release and activation of sensory fibers that stimulate the brainstem respiratory center to produce hyperventilation. The molecular mechanisms underlying O2 sensing by glomus cells have, however, remained elusive. Here we discuss recent data demonstrating that ablation of mitochondrial Ndufs2 gene selectively abolishes sensitivity of glomus cells to hypoxia, maintaining responsiveness to hypercapnia or hypoglycemia. These data suggest that reactive oxygen species and NADH generated in mitochondrial complex I during hypoxia are signaling molecules that modulate membrane K+ channels. We propose that the structural substrates for acute O2 sensing in CB glomus cells are “O2-sensing microdomains” formed by mitochondria and neighboring K+ channels in the plasma membrane. Acute O2 sensing by peripheral chemoreceptors depends on K+ channels. Mitochondrial complex I function is required for acute O2 sensing. Reactive oxygen species inhibits background K+ channels during acute hypoxia. Pyridine nucleotides may signal voltage-gated K+ channels during acute hypoxia.
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Affiliation(s)
- Lin Gao
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Seville, Spain.
| | - Patricia González-Rodríguez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Seville, Spain
| | - Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Seville, Spain
| | - José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Seville, Spain.
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104
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Harvey LD, Chan SY. Emerging Metabolic Therapies in Pulmonary Arterial Hypertension. J Clin Med 2017; 6:jcm6040043. [PMID: 28375184 PMCID: PMC5406775 DOI: 10.3390/jcm6040043] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 12/26/2022] Open
Abstract
Pulmonary hypertension (PH) is an enigmatic vascular disorder characterized by pulmonary vascular remodeling and increased pulmonary vascular resistance, ultimately resulting in pressure overload, dysfunction, and failure of the right ventricle. Current medications for PH do not reverse or prevent disease progression, and current diagnostic strategies are suboptimal for detecting early-stage disease. Thus, there is a substantial need to develop new diagnostics and therapies that target the molecular origins of PH. Emerging investigations have defined metabolic aberrations as fundamental and early components of disease manifestation in both pulmonary vasculature and the right ventricle. As such, the elucidation of metabolic dysregulation in pulmonary hypertension allows for greater therapeutic insight into preventing, halting, or even reversing disease progression. This review will aim to discuss (1) the reprogramming and dysregulation of metabolic pathways in pulmonary hypertension; (2) the emerging therapeutic interventions targeting these metabolic pathways; and (3) further innovation needed to overcome barriers in the treatment of this devastating disease.
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Affiliation(s)
- Lloyd D Harvey
- Medical Scientist Training Program, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
| | - Stephen Y Chan
- Division of Cardiology, Center for Pulmonary Vascular Biology and Medicine, Pittsburgh Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
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105
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Binelli A, Del Giacco L, Santo N, Bini L, Magni S, Parolini M, Madaschi L, Ghilardi A, Maggioni D, Ascagni M, Armini A, Prosperi L, Landi C, La Porta C, Della Torre C. Carbon nanopowder acts as a Trojan-horse for benzo(α)pyrene in Danio rerio embryos. Nanotoxicology 2017; 11:371-381. [DOI: 10.1080/17435390.2017.1306130] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- A. Binelli
- Department of Biosciences, University of Milan, Milan, Italy
| | - L. Del Giacco
- Department of Biosciences, University of Milan, Milan, Italy
| | - N. Santo
- Department of Biosciences, University of Milan, Milan, Italy
| | - L. Bini
- Department of Life Science, University of Siena, Siena, Italy
| | - S. Magni
- Department of Biosciences, University of Milan, Milan, Italy
| | - M. Parolini
- Department of Biosciences, University of Milan, Milan, Italy
| | - L. Madaschi
- Department of Biosciences, University of Milan, Milan, Italy
| | - A. Ghilardi
- Department of Biosciences, University of Milan, Milan, Italy
| | - D. Maggioni
- Department of Chemistry, University of Milan, Milan, Italy
| | - M. Ascagni
- Department of Biosciences, University of Milan, Milan, Italy
| | - A. Armini
- Department of Life Science, University of Siena, Siena, Italy
| | - L. Prosperi
- Department of Biosciences, University of Milan, Milan, Italy
| | - C. Landi
- Department of Life Science, University of Siena, Siena, Italy
| | - C. La Porta
- Department of Biosciences, University of Milan, Milan, Italy
| | - C. Della Torre
- Department of Biosciences, University of Milan, Milan, Italy
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106
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McElroy GS, Chandel NS. Mitochondria control acute and chronic responses to hypoxia. Exp Cell Res 2017; 356:217-222. [PMID: 28327410 DOI: 10.1016/j.yexcr.2017.03.034] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 03/16/2017] [Indexed: 12/30/2022]
Abstract
There are numerous mechanisms by which mammals respond to hypoxia. These include acute changes in pulmonary arterial tone due to smooth muscle cell contraction, acute increases in respiration triggered by the carotid body chemosensory cells, and chronic changes such as induction of red blood cell proliferation and angiogenesis by hypoxia inducible factor targets erythropoietin and vascular endothelial growth factor, respectively. Mitochondria account for the majority of oxygen consumption in the cell and have recently been appreciated to serve as signaling organelles required for the initiation or propagation of numerous homeostatic mechanisms. Mitochondria can influence cell signaling by production of reactive oxygen species and metabolites. Here we review recent evidence that mitochondrial signals can imitate acute and chronic hypoxia responses.
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Affiliation(s)
- G S McElroy
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
| | - N S Chandel
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States.
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107
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Maarman GJ, Schulz R, Sliwa K, Schermuly RT, Lecour S. Novel putative pharmacological therapies to protect the right ventricle in pulmonary hypertension: a review of current literature. Br J Pharmacol 2017; 174:497-511. [PMID: 28099680 DOI: 10.1111/bph.13721] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 09/06/2016] [Accepted: 09/27/2016] [Indexed: 12/15/2022] Open
Abstract
Pulmonary hypertension (PH) is defined by elevated mean pulmonary artery pressure following the pathological remodelling of small pulmonary arteries. An increase in right ventricular (RV) afterload results in RV hypertrophy and RV failure. The pathophysiology of PH, and RV remodelling in particular, is not well understood, thus explaining, at least in part, why current PH therapies have a limited effect. Existing therapies mostly target the pulmonary circulation. Because the remodelled RV fails to support normal cardiac function, patients eventually succumb from RV failure. Developing novel therapies that directly target the function of the RV may therefore benefit patients with PH. In the past decade, several promising studies have investigated novel cardioprotective strategies in experimental models of PH. This review aims to comprehensively discuss and highlight these novel experimental approaches to confer, in the long-term, greater health benefit in patients with PH.
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Affiliation(s)
- Gerald J Maarman
- Hatter Institute for Cardiovascular Research in Africa (HICRA) and MRC Inter-University Cape Heart Group, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Rainer Schulz
- Institute of Physiology, Justus Liebig University Giessen, Giessen, Germany
| | - Karen Sliwa
- Hatter Institute for Cardiovascular Research in Africa (HICRA) and MRC Inter-University Cape Heart Group, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Ralph Theo Schermuly
- Universities of Giessen and Marburg Lung Centre, Member of the German Lung Centre (DZL), Justus Liebig University Giessen, Giessen, Germany
| | - Sandrine Lecour
- Hatter Institute for Cardiovascular Research in Africa (HICRA) and MRC Inter-University Cape Heart Group, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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108
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Hussain A, Suleiman MS, George SJ, Loubani M, Morice A. Hypoxic Pulmonary Vasoconstriction in Humans: Tale or Myth. Open Cardiovasc Med J 2017; 11:1-13. [PMID: 28217180 PMCID: PMC5301302 DOI: 10.2174/1874192401711010001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 12/02/2016] [Accepted: 12/09/2016] [Indexed: 12/13/2022] Open
Abstract
Hypoxic Pulmonary vasoconstriction (HPV) describes the physiological adaptive process of lungs to preserves systemic oxygenation. It has clinical implications in the development of pulmonary hypertension which impacts on outcomes of patients undergoing cardiothoracic surgery. This review examines both acute and chronic hypoxic vasoconstriction focusing on the distinct clinical implications and highlights the role of calcium and mitochondria in acute versus the role of reactive oxygen species and Rho GTPases in chronic HPV. Furthermore it identifies gaps of knowledge and need for further research in humans to clearly define this phenomenon and the underlying mechanism.
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Affiliation(s)
- A Hussain
- Department of Cardiothoracic Surgery, Castle Hill Hospital, Castle Road, Cottingham, HU16 5JQ, UK
| | - M S Suleiman
- School of Clinical Sciences, Bristol Royal Infirmary, Marlborough Street, Bristol, BS2 8HW, UK
| | - S J George
- School of Clinical Sciences, Bristol Royal Infirmary, Marlborough Street, Bristol, BS2 8HW, UK
| | - M Loubani
- Department of Cardiothoracic Surgery, Castle Hill Hospital, Castle Road, Cottingham, HU16 5JQ, UK
| | - A Morice
- Department of Respiratory Medicine, Castle Hill Hospital, Castle Road, Cottingham, HU16 5JQ, UK
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109
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Thébaud B. Impaired Lung Development and Neonatal Lung Diseases: A Never-Ending (Vascular) Story. J Pediatr 2017; 180:11-13. [PMID: 27793337 DOI: 10.1016/j.jpeds.2016.10.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 10/07/2016] [Indexed: 12/31/2022]
Affiliation(s)
- Bernard Thébaud
- Department of Pediatrics Children's Hospital of Eastern Ontario and Children's Hospital of Ontario Research Institute (CHEORI); Sinclair Centre for Regenerative Medicine Ottawa Hospital Research Institute (OHRI); Department of Cellular and Molecular Biology University of Ottawa Ottawa, Ontario, Canada.
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110
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Dunham-Snary KJ, Wu D, Sykes EA, Thakrar A, Parlow LRG, Mewburn JD, Parlow JL, Archer SL. Hypoxic Pulmonary Vasoconstriction: From Molecular Mechanisms to Medicine. Chest 2017; 151:181-192. [PMID: 27645688 PMCID: PMC5310129 DOI: 10.1016/j.chest.2016.09.001] [Citation(s) in RCA: 262] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 09/01/2016] [Accepted: 09/02/2016] [Indexed: 12/11/2022] Open
Abstract
Hypoxic pulmonary vasoconstriction (HPV) is a homeostatic mechanism that is intrinsic to the pulmonary vasculature. Intrapulmonary arteries constrict in response to alveolar hypoxia, diverting blood to better-oxygenated lung segments, thereby optimizing ventilation/perfusion matching and systemic oxygen delivery. In response to alveolar hypoxia, a mitochondrial sensor dynamically changes reactive oxygen species and redox couples in pulmonary artery smooth muscle cells (PASMC). This inhibits potassium channels, depolarizes PASMC, activates voltage-gated calcium channels, and increases cytosolic calcium, causing vasoconstriction. Sustained hypoxia activates rho kinase, reinforcing vasoconstriction, and hypoxia-inducible factor (HIF)-1α, leading to adverse pulmonary vascular remodeling and pulmonary hypertension (PH). In the nonventilated fetal lung, HPV diverts blood to the systemic vasculature. After birth, HPV commonly occurs as a localized homeostatic response to focal pneumonia or atelectasis, which optimizes systemic Po2 without altering pulmonary artery pressure (PAP). In single-lung anesthesia, HPV reduces blood flow to the nonventilated lung, thereby facilitating thoracic surgery. At altitude, global hypoxia causes diffuse HPV, increases PAP, and initiates PH. Exaggerated or heterogeneous HPV contributes to high-altitude pulmonary edema. Conversely, impaired HPV, whether due to disease (eg, COPD, sepsis) or vasodilator drugs, promotes systemic hypoxemia. Genetic and epigenetic abnormalities of this oxygen-sensing pathway can trigger normoxic activation of HIF-1α and can promote abnormal metabolism and cell proliferation. The resulting pseudohypoxic state underlies the Warburg metabolic shift and contributes to the neoplasia-like phenotype of PH. HPV and oxygen sensing are important in human health and disease.
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Affiliation(s)
| | - Danchen Wu
- Department of Medicine, Queen's University, Kingston, ON, Canada
| | - Edward A Sykes
- Department of Medicine, Queen's University, Kingston, ON, Canada
| | - Amar Thakrar
- Department of Medicine, Queen's University, Kingston, ON, Canada
| | - Leah R G Parlow
- Department of Medicine, Queen's University, Kingston, ON, Canada
| | | | - Joel L Parlow
- Department of Anesthesiology and Perioperative Medicine, Queen's University, Kingston, ON, Canada
| | - Stephen L Archer
- Department of Medicine, Queen's University, Kingston, ON, Canada.
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111
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MORI Y, TAKAHASHI N, KUROKAWA T, KIYONAKA S. TRP channels in oxygen physiology: distinctive functional properties and roles of TRPA1 in O 2 sensing. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2017; 93:464-482. [PMID: 28769017 PMCID: PMC5713176 DOI: 10.2183/pjab.93.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 04/20/2017] [Indexed: 05/22/2023]
Abstract
Transient Receptor Potential (TRP) proteins form cation channels characterized by a wide variety of activation triggers. Here, we overview a group of TRP channels that respond to reactive redox species to transduce physiological signals, with a focus on TRPA1 and its role in oxygen physiology. Our systematic evaluation of oxidation sensitivity using cysteine-selective reactive disulphides with different redox potentials reveals that TRPA1 has the highest sensitivity to oxidants/electrophiles among the TRP channels, which enables it to sense O2. Proline hydroxylation by O2-dependent hydroxylases also regulates the O2-sensing function by inhibiting TRPA1 in normoxia; TRPA1 is activated by hypoxia through relief from the inhibition and by hyperoxia through cysteine oxidation that overrides the inhibition. TRPA1 enhances neuronal discharges induced by hyperoxia and hypoxia in the vagus to underlie respiratory adaptation to changes in O2 availability. This importance of TRPA1 in non-carotid body O2 sensors can be extended to the universal significance of redox-sensitive TRP channels in O2 adaptation.
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Affiliation(s)
- Yasuo MORI
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
- Correspondence should be addressed: Y. Mori, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan (e-mail: )
| | - Nobuaki TAKAHASHI
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Tatsuki KUROKAWA
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Shigeki KIYONAKA
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, Japan
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112
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Erol S, Gürün Kaya A, Arslan Ciftçi F, Çiledağ A, Şen E, Kaya A, Çelik G, Savaş İ. Is oxygen saturation variable of simplified pulmonary embolism severity index reliable for identification of patients, suitable for outpatient treatment. CLINICAL RESPIRATORY JOURNAL 2016; 12:762-766. [PMID: 27997739 DOI: 10.1111/crj.12591] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 10/16/2016] [Accepted: 11/11/2016] [Indexed: 11/29/2022]
Abstract
INTRODUCTION The pulmonary embolism severity index (PESI) or simplified version (sPESI) are widely validated risk scores for the identification of eligible patients for outpatient treatment. Saturation is one of these criteria. For this metric, saturation of 90% or greater is assigned zero points. However, 90% saturation does not always exclude hypoxemic respiratory failure. OBJECTIVE The aims of this study were first was to define corresponding partial arterial oxygen pressure (PaO2 ) values according to saturation in pulmonary embolism (PE) patients, and the second was to define a target saturation that can exclude hypoxemic respiratory failure and enable secure discharge of PE patients from emergency departments. METHODS This is a retrospective study. To determine the optimal saturation value by which to detect hypoxemic respiratory failure, we generated receiver operating characteristic (ROC) curves and calculated the negative predictive value. RESULTS Total of 65 patients were included in this study. Mean PaO2 levels from SaO2 89% to SaO2 93% were 52.8, 57.1, 57.3, 61, and 63.8 mmHg, respectively. ROC curve analysis revealed SaO2 level of 91.5% to be optimal target saturation for excluding respiratory failure with 84.6% specificity and 89.7% sensitivity; area under the curve was 0.885 (95% CI 0.796-0.975). The negative predictive value was 80% for SaO2 level of 92%. CONCLUSION Patients with PE may be in respiratory failure despite an oxyhemoglobin saturation of ≥90%. Although saturation is likely more important than precise PaO2 in tissue oxygenation, clinicians should be aware of the physiological effects of hypoxemia and take this into account before making outpatient treatment decisions.
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Affiliation(s)
- Serhat Erol
- Pulmonary Diseases Department, School of Medicine, Ankara University, Ankara, Turkey
| | - Aslıhan Gürün Kaya
- Pulmonary Diseases Department, School of Medicine, Ankara University, Ankara, Turkey
| | - Fatma Arslan Ciftçi
- Pulmonary Diseases Department, School of Medicine, Ankara University, Ankara, Turkey
| | - Aydın Çiledağ
- Pulmonary Diseases Department, School of Medicine, Ankara University, Ankara, Turkey
| | - Elif Şen
- Pulmonary Diseases Department, School of Medicine, Ankara University, Ankara, Turkey
| | - Akın Kaya
- Pulmonary Diseases Department, School of Medicine, Ankara University, Ankara, Turkey
| | - Gökhan Çelik
- Pulmonary Diseases Department, School of Medicine, Ankara University, Ankara, Turkey
| | - İsmail Savaş
- Pulmonary Diseases Department, School of Medicine, Ankara University, Ankara, Turkey
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113
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Brinks L, Moonen RMJ, Moral-Sanz J, Barreira B, Kessels L, Perez-Vizcaino F, Cogolludo A, Villamor E. Hypoxia-induced contraction of chicken embryo mesenteric arteries: mechanisms and developmental changes. Am J Physiol Regul Integr Comp Physiol 2016; 311:R858-R869. [DOI: 10.1152/ajpregu.00461.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 08/10/2016] [Indexed: 11/22/2022]
Abstract
The fetal cardiovascular responses to acute hypoxia include a redistribution of the cardiac output toward the heart and the brain at the expense of other organs, such as the intestine. We hypothesized that hypoxia exerts a direct effect on the mesenteric artery (MA) that may contribute to this response. Using wire myography, we investigated the response to hypoxia (Po2 ~2.5 kPa for 20 min) of isolated MAs from 15- to 21-day chicken embryos (E15, E19, E21), and 1- to 45-day-old chickens (P1, P3, P14, P45). Agonist-induced pretone or an intact endothelium were not required to obtain a consistent and reproducible response to hypoxia, which showed a pattern of initial rapid phasic contraction followed by a sustained tonic contraction. Phasic contraction was reduced by elimination of extracellular Ca2+ or by presence of the neurotoxin tetrodotoxin, the α1-adrenoceptor antagonist prazosin, or inhibitors of L-type voltage-gated Ca2+ channels (nifedipine), mitochondrial electron transport chain (rotenone and antimycin A), and NADPH oxidase (VAS2870). The Rho-kinase inhibitor Y27632 impaired both phasic and tonic contraction and, when combined with elimination of extracellular Ca2+, hypoxia-induced contraction was virtually abolished. Hypoxic MA contraction was absent at E15 but present from E19 and increased toward the first days posthatching. It then decreased during the first weeks of life and P45 MAs were unable to sustain hypoxia-induced contraction over time. In conclusion, the results of the present study demonstrate that hypoxic vasoconstriction is an intrinsic feature of chicken MA vascular smooth muscle cells during late embryogenesis and the perinatal period.
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Affiliation(s)
- Leonie Brinks
- Department of Pediatrics, Maastricht University Medical Center (MUMC+), School for Oncology and Developmental Biology (GROW), Maastricht, The Netherlands
| | - Rob M. J. Moonen
- Department of Pediatrics, Maastricht University Medical Center (MUMC+), School for Oncology and Developmental Biology (GROW), Maastricht, The Netherlands
- Department of Pediatrics, Zuyderland Medical Center, Heerlen, The Netherlands; and
| | - Javier Moral-Sanz
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid, Centro de Investigaciones Biomédicas en Red de Enfermedades Respiratorias (CIBERES), Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Bianca Barreira
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid, Centro de Investigaciones Biomédicas en Red de Enfermedades Respiratorias (CIBERES), Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Lilian Kessels
- Department of Pediatrics, Maastricht University Medical Center (MUMC+), School for Oncology and Developmental Biology (GROW), Maastricht, The Netherlands
| | - Francisco Perez-Vizcaino
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid, Centro de Investigaciones Biomédicas en Red de Enfermedades Respiratorias (CIBERES), Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Angel Cogolludo
- Department of Pharmacology, School of Medicine, Universidad Complutense de Madrid, Centro de Investigaciones Biomédicas en Red de Enfermedades Respiratorias (CIBERES), Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Eduardo Villamor
- Department of Pediatrics, Maastricht University Medical Center (MUMC+), School for Oncology and Developmental Biology (GROW), Maastricht, The Netherlands
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114
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Affiliation(s)
- Jacques Pouyssegur
- Centre Scientifique de Monaco (CSM), Monaco; Institute for Research on Cancer & Aging (IRCAN), Centre A. Lacassagne, University of Nice-Sophia Antipolis, Nice, France.
| | - José López-Barneo
- Institute of Biomedicine of Seville (IBiS), Hospital Universitario Virgen del Rocío/CSIC /Universidad de Sevilla.
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115
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Sedation with Dexmedetomidine or Propofol Impairs Hypoxic Control of Breathing in Healthy Male Volunteers. Anesthesiology 2016; 125:700-15. [DOI: 10.1097/aln.0000000000001236] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Abstract
Background
In contrast to general anesthetics such as propofol, dexmedetomidine when used for sedation has been put forward as a drug with minimal effects on respiration. To obtain a more comprehensive understanding of the regulation of breathing during sedation with dexmedetomidine, the authors compared ventilatory responses to hypoxia and hypercapnia during sedation with dexmedetomidine and propofol.
Methods
Eleven healthy male volunteers entered this randomized crossover study. Sedation was administered as an intravenous bolus followed by an infusion and monitored by Observer’s Assessment of Alertness/Sedation (OAA/S) scale, Richmond Agitation Sedation Scale, and Bispectral Index Score. Hypoxic and hypercapnic ventilatory responses were measured at rest, during sedation (OAA/S 2 to 4), and after recovery. Drug exposure was verified with concentration analysis in plasma.
Results
Ten subjects completed the study. The OAA/S at the sedation goal was 3 (3 to 4) (median [minimum to maximum]) for both drugs. Bispectral Index Score was 82 ± 8 and 75 ± 3, and the drug concentrations in plasma at the sedation target were 0.66 ± 0.14 ng/ml and 1.26 ± 0.36 μg/ml for dexmedetomidine and propofol, respectively. Compared with baseline, sedation reduced hypoxic ventilation to 59 and 53% and the hypercapnic ventilation to 82 and 86% for dexmedetomidine and propofol, respectively. In addition, some volunteers displayed upper airway obstruction and episodes of apnea during sedation.
Conclusions
Dexmedetomidine-induced sedation reduces ventilatory responses to hypoxia and hypercapnia to a similar extent as sedation with propofol. This finding implies that sedation with dexmedetomidine interacts with both peripheral and central control of breathing.
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116
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Alvarado A, Arce I. Metabolic Functions of the Lung, Disorders and Associated Pathologies. J Clin Med Res 2016; 8:689-700. [PMID: 27635172 PMCID: PMC5012236 DOI: 10.14740/jocmr2668w] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2016] [Indexed: 01/04/2023] Open
Abstract
The primary function of the lungs is gas exchange. Approximately 400 million years ago, the Earth's atmosphere gained enough oxygen in the gas phase for the animals that emerged from the sea to breathe air. The first lungs were merely primitive air sacs with a few vessels in the walls that served as accessory organs of gas exchange to supplement the gills. Eons later, as animals grew accustomed to a solely terrestrial life, the lungs became highly compartmentalized to provide the vast air-blood surface necessary for O2 uptake and CO2 elimination, and a respiratory control system was developed to regulate breathing in accordance with metabolic demands and other needs. With the evolution and phylogenetic development, lungs were taking a variety of other specialized functions to maintain homeostasis, which we will call the non-respiratory functions of the lung and that often, and by mistake, are believed to have little or no connection with the replacement gas. In this review, we focus on the metabolic functions of the lung, perhaps the least known, and mainly, in the lipid metabolism and blood-adult lung vascular endothelium interaction. When these functions are altered, respiratory disorders or diseases appear, which are discussed concisely, emphasizing how they impact the most important function of the lungs: external respiration.
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Affiliation(s)
- Alcibey Alvarado
- Internal Medicine and Neumology, Clinica de Diagnostico Medico, San Jose, Costa Rica
| | - Isabel Arce
- Medicine and General Surgery, Medicine School, University of Costa Rica, San Jose, Costa Rica
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117
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Veith C, Kraut S, Wilhelm J, Sommer N, Quanz K, Seeger W, Brandes RP, Weissmann N, Schröder K. NADPH oxidase 4 is not involved in hypoxia-induced pulmonary hypertension. Pulm Circ 2016; 6:397-400. [PMID: 27683617 DOI: 10.1086/687756] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- C Veith
- Universities of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Excellence Cluster Cardio-Pulmonary System (ECCPS), Giessen, Germany
| | - S Kraut
- UGMLC, member of the DZL, ECCPS, Giessen, Germany
| | - J Wilhelm
- UGMLC, member of the DZL, ECCPS, Giessen, Germany
| | - N Sommer
- UGMLC, member of the DZL, ECCPS, Giessen, Germany
| | - K Quanz
- UGMLC, member of the DZL, ECCPS, Giessen, Germany
| | - W Seeger
- UGMLC, member of the DZL, ECCPS, Giessen, Germany
| | - R P Brandes
- Institute for Cardiovascular Physiology, Goethe University Frankfurt, ECCPS, Frankfurt, Germany
| | - N Weissmann
- UGMLC, member of the DZL, ECCPS, Giessen, Germany
| | - K Schröder
- Institute for Cardiovascular Physiology, Goethe University Frankfurt, ECCPS, Frankfurt, Germany
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118
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Santos-Ribeiro D, Mendes-Ferreira P, Maia-Rocha C, Adão R, Leite-Moreira AF, Brás-Silva C. Pulmonary arterial hypertension: Basic knowledge for clinicians. Arch Cardiovasc Dis 2016; 109:550-561. [PMID: 27595464 DOI: 10.1016/j.acvd.2016.03.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 03/29/2016] [Accepted: 03/31/2016] [Indexed: 01/29/2023]
Abstract
Pulmonary arterial hypertension is a progressive syndrome based on diverse aetiologies, which is characterized by a persistent increase in pulmonary vascular resistance and overload of the right ventricle, leading to heart failure and death. Currently, none of the available treatments is able to cure pulmonary arterial hypertension; additional research is therefore needed to unravel the associated pathophysiological mechanisms. This review summarizes current knowledge related to this disorder, and the several experimental animal models that can mimic pulmonary arterial hypertension and are available for translational research.
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Affiliation(s)
- Diana Santos-Ribeiro
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, Cardiovascular Research and Development Centre, University of Porto, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Pedro Mendes-Ferreira
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, Cardiovascular Research and Development Centre, University of Porto, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Carolina Maia-Rocha
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, Cardiovascular Research and Development Centre, University of Porto, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Rui Adão
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, Cardiovascular Research and Development Centre, University of Porto, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Adelino F Leite-Moreira
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, Cardiovascular Research and Development Centre, University of Porto, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Carmen Brás-Silva
- Department of Physiology and Cardiothoracic Surgery, Faculty of Medicine, Cardiovascular Research and Development Centre, University of Porto, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal; Faculty of Nutrition and Food Sciences, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
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119
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Ortega-de San Luis C, Pascual A. Simultaneous Detection of Both GDNF and GFRα1 Expression Patterns in the Mouse Central Nervous System. Front Neuroanat 2016; 10:73. [PMID: 27445711 PMCID: PMC4919337 DOI: 10.3389/fnana.2016.00073] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 06/09/2016] [Indexed: 12/20/2022] Open
Abstract
Glial cell line-derived neurotrophic factor (GDNF) is proposed as a therapeutic tool in Parkinson's disease, addiction-related disorders, and neurodegenerative conditions affecting motor neurons (MNs). Despite the high amount of work about GDNF therapeutic application, the neuronal circuits requiring GDNF trophic support in the brain and spinal cord (SC) are poorly characterized. Here, we defined GDNF and GDNF family receptor-α 1 (GFRα1) expression pattern in the brain and SC of newborn and adult mice. We performed systematic and simultaneous detection of EGFP and LacZ expressing alleles in reporter mice and asked whether modifications of this signaling pathway lead to a significant central nervous system (CNS) alteration. GFRα1 was predominantly expressed by neurons but also by an unexpected population of non-neuronal cells. GFRα1 expression pattern was wider in neonatal than in adult CNS and GDNF expression was restricted in comparison with GFRα1 at both developmental time points. The use of confocal microscopy to imaging X-gal deposits and EGFP allowed us to identify regions containing cells that expressed both proteins and to discriminate between auto and non-autotrophic signaling. We also suggested long-range GDNF-GFRα1 circuits taking advantage of the ability of the EGFP genetically encoded reporter to label long distance projecting axons. The complete elimination of either the ligand or the receptor during development did not produce major abnormalities, suggesting a preponderant role for GDNF signaling during adulthood. In the SC, our results pointed to local modulatory interneurons as the main target of GDNF produced by Clarke's column (CC) cells. Our work increases the understanding on how GDNF signals in the CNS and establish a crucial framework for posterior studies addressing either the biological role of GDNF or the optimization of trophic factor-based therapies.
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Affiliation(s)
- Clara Ortega-de San Luis
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla Seville, Spain
| | - Alberto Pascual
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla Seville, Spain
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120
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Singh N, Manhas A, Kaur G, Jagavelu K, Hanif K. Inhibition of fatty acid synthase is protective in pulmonary hypertension. Br J Pharmacol 2016; 173:2030-45. [PMID: 27061087 PMCID: PMC4882492 DOI: 10.1111/bph.13495] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 03/21/2016] [Accepted: 03/26/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE In pulmonary hypertension (PH), similar to cancer, there is altered energy metabolism, apoptosis resistance and cellular proliferation leading to pulmonary vascular remodelling. Proliferating cells exhibit higher rate of de novo fatty acid synthesis to provide lipids for membrane formation and energy production. As inhibition of de novo fatty acid synthesis proved protective in cancer experimentally, therefore, it was hypothesized that modulation of de novo fatty acid synthesis by inhibition of fatty acid synthase (FAS) may prove beneficial for PH. EXPERIMENTAL APPROACH For in vitro studies, human pulmonary artery smooth muscle cells (HPASMCs) were exposed to hypoxia and to induce PH in vivo, rats were treated with monocrotaline (MCT). FAS was inhibited by siRNA (60 nM) and C75 (2 mg·kg(-1) , i.p. once a week for 5 weeks) in in vitro and in vivo studies respectively. RESULTS Increased expression and activity of FAS were observed in hypoxic HPASMCs and lungs of MCT-treated rats. Inhibition of FAS increased apoptosis and glucose oxidation, but decreased proliferation and markers of autophagy, glycolysis and insulin resistance in hypoxic HPASMCs. It also improved the mitochondrial functions as evident by increased level of ATP and restoration of normal level of ROS and membrane potential of mitochondria. In MCT-treated rats, FAS inhibition decreased right ventricular pressure, hypertrophy, pulmonary vascular remodelling (increased apoptosis and decreased proliferation of cells) and endothelial dysfunction in lungs. CONCLUSIONS Our results demonstrate that FAS activity is modulated in PH, and its inhibition may provide a new therapeutic approach to treat PH.
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Affiliation(s)
- Neetu Singh
- Division of PharmacologyCSIR‐Central Drug Research InstituteLucknowIndia
- Academy of Scientific and Innovative ResearchNew DelhiIndia
| | - Amit Manhas
- Division of PharmacologyCSIR‐Central Drug Research InstituteLucknowIndia
| | - Gurpreet Kaur
- Division of PharmacologyCSIR‐Central Drug Research InstituteLucknowIndia
| | - Kumaravelu Jagavelu
- Division of PharmacologyCSIR‐Central Drug Research InstituteLucknowIndia
- Academy of Scientific and Innovative ResearchNew DelhiIndia
| | - Kashif Hanif
- Division of PharmacologyCSIR‐Central Drug Research InstituteLucknowIndia
- Academy of Scientific and Innovative ResearchNew DelhiIndia
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121
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Frise MC, Cheng HY, Nickol AH, Curtis MK, Pollard KA, Roberts DJ, Ratcliffe PJ, Dorrington KL, Robbins PA. Clinical iron deficiency disturbs normal human responses to hypoxia. J Clin Invest 2016; 126:2139-50. [PMID: 27140401 PMCID: PMC4887172 DOI: 10.1172/jci85715] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/10/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Iron bioavailability has been identified as a factor that influences cellular hypoxia sensing, putatively via an action on the hypoxia-inducible factor (HIF) pathway. We therefore hypothesized that clinical iron deficiency would disturb integrated human responses to hypoxia. METHODS We performed a prospective, controlled, observational study of the effects of iron status on hypoxic pulmonary hypertension. Individuals with absolute iron deficiency (ID) and an iron-replete (IR) control group were exposed to two 6-hour periods of isocapnic hypoxia. The second hypoxic exposure was preceded by i.v. infusion of iron. Pulmonary artery systolic pressure (PASP) was serially assessed with Doppler echocardiography. RESULTS Thirteen ID individuals completed the study and were age- and sex-matched with controls. PASP did not differ by group or study day before each hypoxic exposure. During the first 6-hour hypoxic exposure, the rise in PASP was 6.2 mmHg greater in the ID group (absolute rises 16.1 and 10.7 mmHg, respectively; 95% CI for difference, 2.7-9.7 mmHg, P = 0.001). Intravenous iron attenuated the PASP rise in both groups; however, the effect was greater in ID participants than in controls (absolute reductions 11.1 and 6.8 mmHg, respectively; 95% CI for difference in change, -8.3 to -0.3 mmHg, P = 0.035). Serum erythropoietin responses to hypoxia also differed between groups. CONCLUSION Clinical iron deficiency disturbs normal responses to hypoxia, as evidenced by exaggerated hypoxic pulmonary hypertension that is reversed by subsequent iron administration. Disturbed hypoxia sensing and signaling provides a mechanism through which iron deficiency may be detrimental to human health. TRIAL REGISTRATION ClinicalTrials.gov (NCT01847352). FUNDING M.C. Frise is the recipient of a British Heart Foundation Clinical Research Training Fellowship (FS/14/48/30828). K.L. Dorrington is supported by the Dunhill Medical Trust (R178/1110). D.J. Roberts was supported by R&D funding from National Health Service (NHS) Blood and Transplant and a National Institute for Health Research (NIHR) Programme grant (RP-PG-0310-1004). This research was funded by the NIHR Oxford Biomedical Research Centre Programme.
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Affiliation(s)
- Matthew C. Frise
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Hung-Yuan Cheng
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Annabel H. Nickol
- Oxford University Hospitals NHS Foundation Trust, Oxford Centre for Respiratory Medicine, Churchill Hospital, Oxford, United Kingdom
| | - M. Kate Curtis
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Karen A. Pollard
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - David J. Roberts
- University of Oxford, Nuffield Department of Clinical Laboratory Sciences, and National Health Service Blood and Transplant Oxford Centre, John Radcliffe Hospital, Oxford, United Kingdom
| | - Peter J. Ratcliffe
- University of Oxford, Nuffield Department of Medicine, Henry Wellcome Building for Molecular Physiology, Old Road Campus, Headington, Oxford, United Kingdom
| | - Keith L. Dorrington
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Peter A. Robbins
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
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122
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Yamamoto K, Namba N, Kubota T, Usui T, Takahashi K, Kitaoka T, Fujiwara M, Hori Y, Kogaki S, Oue T, Morii E, Ozono K. Pheochromocytoma complicated by cyanotic congenital heart disease: a case report. Clin Pediatr Endocrinol 2016; 25:59-65. [PMID: 27212797 PMCID: PMC4860516 DOI: 10.1297/cpe.25.59] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 01/16/2016] [Indexed: 11/04/2022] Open
Abstract
Coincidental cyanotic congenital heart disease and pheochromocytoma is uncommon, although some cases have been reported. We describe a girl aged 15 yr and 11 mo with pheochromocytoma and tricuspid atresia treated by performing the Fontan surgery. The patient did not have any specific symptoms of syndrome related to pheochromoytoma or a family history of pheochromocytoma. During cardiac catheterization, her blood pressure increased markedly, and an α-blocker was administered. Catecholamine hypersecretion was observed in the blood and urine, and abdominal computed tomography revealed a tumor in the right adrenal gland. Scintigraphy showed marked accumulation of (123)I-metaiodobenzylguanidine in the tumor, which led to a diagnosis of pheochromocytoma. We did not detect any germline mutations in the RET, VHL, SDHB, SDHD, TMEM127, or MAX genes. This patient had experienced mild systemic hypoxia since birth, which may have contributed to the development of pheochromocytoma.
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Affiliation(s)
- Keiko Yamamoto
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Noriyuki Namba
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan; Department of Pediatrics, Japan Community Health Care Organization, Osaka Hospital, Osaka, Japan
| | - Takuo Kubota
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Takeshi Usui
- Clinical Research Institute, National Hospital Organization, Kyoto Medical Center, Kyoto, Japan
| | - Kunihiko Takahashi
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Taichi Kitaoka
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Makoto Fujiwara
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yumiko Hori
- Department of Pathology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Shigetoyo Kogaki
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Takaharu Oue
- Department of Pediatric Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Eiichi Morii
- Department of Pathology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
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123
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Pardal R, López Barneo J. Mature neurons modulate neurogenesis through chemical signals acting on neural stem cells. Dev Growth Differ 2016; 58:456-62. [PMID: 27101323 DOI: 10.1111/dgd.12283] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 03/09/2016] [Accepted: 03/09/2016] [Indexed: 12/17/2022]
Abstract
The discovery of neural stem cells has revealed a much higher structural and functional plasticity in the adult nervous system than previously anticipated. Progenitor cells are able to give rise to new neurons and glial cells when needed, thanks to their surveillance of the environment from the germinal niches. Multiple different factors define neural stem cell niches, including cellular and non-cellular components. Innervation of neurogenic centers is crucial, as it allows the functional connection between stem cell behavior and surrounding neuronal activity. Although the association between organismal behavior and neurogenesis is well documented, much less is known about the cellular and molecular mechanisms by which neurons control stem cell activity. In this review we discuss the existing data on this type of regulation from the three best characterized germinal niches in the adult nervous system: the subventricular zone, the hippocampal subgranular zone, and the carotid body. In all cases, neuronal activity modulates stem cell behavior either by neurotransmitter spillover or by synaptic-like contacts. Currently, the molecular mechanisms underlying mature neuron-stem cell interaction are being clarified. Functional consequences and potential clinical relevance of these phenomena are also discussed.
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Affiliation(s)
- Ricardo Pardal
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain
| | - José López Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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124
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Pan J, Bishop T, Ratcliffe PJ, Yeger H, Cutz E. Hyperplasia and hypertrophy of pulmonary neuroepithelial bodies, presumed airway hypoxia sensors, in hypoxia-inducible factor prolyl hydroxylase-deficient mice. HYPOXIA (AUCKLAND, N.Z.) 2016; 4:69-80. [PMID: 27800509 PMCID: PMC5085281 DOI: 10.2147/hp.s103957] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Pulmonary neuroepithelial bodies (NEBs), presumed polymodal airway sensors, consist of innervated clusters of amine (serotonin) and peptide-producing cells. While NEB responses to acute hypoxia are mediated by a membrane-bound O2 sensor complex, responses to sustained and/or chronic hypoxia involve a prolyl hydroxylase (PHD)-hypoxia-inducible factor-dependent mechanism. We have previously reported hyperplasia of NEBs in the lungs of Phd1-/- mice associated with enhanced serotonin secretion. Here we use a novel multilabel immunofluorescence method to assess NEB distribution, frequency, and size, together with the number and size of NEB cell nuclei, and to colocalize multiple cytoplasmic and nuclear epitopes in the lungs of Phd1-/-, Phd2+/-, and Phd3-/- mice and compare them with wild-type controls. To define the mechanisms of NEB cell hyperplasia, we used antibodies against Mash1 and Prox1 (neurogenic genes involved in NEB cell differentiation/maturation), hypoxia-inducible factor-1alpha, and the cell proliferation marker Ki67. Morphometric analysis of (% total lung area) immunostaining for synaptophysin (% synaptophysin), a cytoplasmic marker of NEB cells, was significantly increased in Phd1-/- and Phd3-/- mice compared to wild-type mice. In addition, NEB size and the number and size of NEB nuclei were also significantly increased, indicating that deficiency of Phds is associated with striking hyperplasia and hypertrophy of NEBs. In Phd2+/- mice, while mean % synaptophysin was comparable to wild-type controls, the NEB size was moderately increased, suggesting an effect even in heterozygotes. NEBs in all Phd-deficient mice showed increased expression of Mash1, Prox1, Ki67, and hypoxia-inducible factor-1alpha, in keeping with enhanced differentiation from precursor cells and a minor component of cell proliferation. Since the loss of PHD activity mimics chronic hypoxia, our data provide critical information on the potential role of PHDs in the pathobiology and mechanisms of NEB cell hyperplasia that is relevant to a number of pediatric lung disorders.
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Affiliation(s)
- Jie Pan
- Division of Pathology, Department of Pediatric Laboratory Medicine, The Research Institute, The Hospital for Sick Children
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Tammie Bishop
- Nuffield Department of Medicine, Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, UK
| | - Peter J Ratcliffe
- Nuffield Department of Medicine, Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, UK
| | - Herman Yeger
- Division of Pathology, Department of Pediatric Laboratory Medicine, The Research Institute, The Hospital for Sick Children
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Ernest Cutz
- Division of Pathology, Department of Pediatric Laboratory Medicine, The Research Institute, The Hospital for Sick Children
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
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125
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Ekanger LA, Polin LA, Shen Y, Haacke EM, Allen MJ. Evaluation of Eu(II) -based positive contrast enhancement after intravenous, intraperitoneal, and subcutaneous injections. CONTRAST MEDIA & MOLECULAR IMAGING 2016; 11:299-303. [PMID: 27028559 DOI: 10.1002/cmmi.1692] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 02/16/2016] [Accepted: 02/23/2016] [Indexed: 12/30/2022]
Abstract
Eu(II) -based contrast agents offer physiologically relevant, metal-based redox sensing that is unachievable with Gd(III) -based contrast agents. To evaluate the in vivo contrast enhancement of Eu(II) as a function of injection type, we performed intravenous, intraperitoneal, and subcutaneous injections in mice. Our data reveal a correlation between reported oxygen content and expected rates of diffusion with the persistence of Eu(II) -based contrast enhancement. Biodistribution studies revealed europium clearance through the liver and kidneys for intravenous and intraperitoneal injections, but no contrast enhancement was observed in organs associated with clearance. These data represent a step toward understanding the behavior of Eu(II) -based complexes in vivo. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Levi A Ekanger
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI, 48202, USA
| | - Lisa A Polin
- Department of Oncology, Wayne State University School of Medicine, Detroit, MI, 4820, USA.,Barbara Ann Karmanos Cancer Institute, Detroit, MI, 48201, USA
| | - Yimin Shen
- Department of Radiology, Wayne State University School of Medicine, Detroit, MI, 48201
| | - E Mark Haacke
- Barbara Ann Karmanos Cancer Institute, Detroit, MI, 48201, USA.,Department of Radiology, Wayne State University School of Medicine, Detroit, MI, 48201
| | - Matthew J Allen
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI, 48202, USA.,Barbara Ann Karmanos Cancer Institute, Detroit, MI, 48201, USA
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126
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Navarro-Guerrero E, Platero-Luengo A, Linares-Clemente P, Cases I, López-Barneo J, Pardal R. Gene Expression Profiling Supports the Neural Crest Origin of Adult Rodent Carotid Body Stem Cells and Identifies CD10 as a Marker for Mesectoderm-Committed Progenitors. Stem Cells 2016; 34:1637-50. [PMID: 26866353 DOI: 10.1002/stem.2331] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 10/14/2015] [Accepted: 12/24/2015] [Indexed: 11/11/2022]
Abstract
Neural stem cells (NSCs) are promising tools for understanding nervous system plasticity and repair, but their use is hampered by the lack of markers suitable for their prospective isolation and characterization. The carotid body (CB) contains a population of peripheral NSCs, which support organ growth during acclimatization to hypoxia. We have set up CB neurosphere (NS) cultures enriched in differentiated neuronal (glomus) cells versus undifferentiated progenitors to investigate molecular hallmarks of cell classes within the CB stem cell (CBSC) niche. Microarray gene expression analysis in NS is compatible with CBSCs being neural crest derived-multipotent progenitor cells able to sustain CB growth upon exposure to hypoxia. Moreover, we have identified CD10 as a marker suitable for isolation of a population of CB mesectoderm-committed progenitor cells. CD10 + cells are resting in normoxia, and during hypoxia they are activated to proliferate and to eventually complete maturation into mesectodermal cells, thus participating in the angiogenesis necessary for CB growth. Our results shed light into the molecular and cellular mechanisms involved in CBSC fate choice, favoring a potential use of these cells for cell therapy. Stem Cells 2016;34:1637-1650.
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Affiliation(s)
- Elena Navarro-Guerrero
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain
| | - Aida Platero-Luengo
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain
| | - Pedro Linares-Clemente
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain
| | - Ildefonso Cases
- Bioinformatics and Computational Biology Group. Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain
| | - José López-Barneo
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Ricardo Pardal
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Spain
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127
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Chapple SJ, Keeley TP, Mastronicola D, Arno M, Vizcay-Barrena G, Fleck R, Siow RCM, Mann GE. Bach1 differentially regulates distinct Nrf2-dependent genes in human venous and coronary artery endothelial cells adapted to physiological oxygen levels. Free Radic Biol Med 2016; 92:152-162. [PMID: 26698668 DOI: 10.1016/j.freeradbiomed.2015.12.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/11/2015] [Accepted: 12/12/2015] [Indexed: 12/18/2022]
Abstract
The effects of physiological oxygen tension on Nuclear Factor-E2-Related Factor 2 (Nrf2)-regulated redox signaling remain poorly understood. We report the first study of Nrf2-regulated signaling in human primary endothelial cells (EC) adapted long-term to physiological O2 (5%). Adaptation of EC to 5% O2 had minimal effects on cell ultrastructure, viability, basal redox status or HIF1-α expression. Affymetrix array profiling and subsequent qPCR/protein validation revealed that induction of select Nrf2 target genes, HO-1 and NQO1, was significantly attenuated in cells adapted to 5% O2, despite nuclear accumulation and DNA binding of Nrf2. Diminished HO-1 induction under 5% O2 was stimulus independent and reversible upon re-adaptation to air or silencing of the Nrf2 repressor Bach1, notably elevated under 5% O2. Induction of GSH-related genes xCT and GCLM were oxygen and Bach1-insensitive during long-term culture under 5% O2, providing the first evidence that genes related to GSH synthesis mediate protection afforded by Nrf2-Keap1 defense pathway in cells adapted to physiological O2 levels encountered in vivo.
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Affiliation(s)
- Sarah J Chapple
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Thomas P Keeley
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Daniela Mastronicola
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Matthew Arno
- Genomics Centre, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Gema Vizcay-Barrena
- Centre for Ultrastructural Imaging, King's College London, London SE1 9NH, UK
| | - Roland Fleck
- Centre for Ultrastructural Imaging, King's College London, London SE1 9NH, UK
| | - Richard C M Siow
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK
| | - Giovanni E Mann
- Cardiovascular Division, British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences & Medicine, King's College London, 150 Stamford Street, London SE1 9NH, UK.
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128
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Oxygen-sensing by arterial chemoreceptors: Mechanisms and medical translation. Mol Aspects Med 2016; 47-48:90-108. [DOI: 10.1016/j.mam.2015.12.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 12/01/2015] [Indexed: 12/30/2022]
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129
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Waypa GB, Smith KA, Schumacker PT. O2 sensing, mitochondria and ROS signaling: The fog is lifting. Mol Aspects Med 2016; 47-48:76-89. [PMID: 26776678 DOI: 10.1016/j.mam.2016.01.002] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/05/2016] [Accepted: 01/07/2016] [Indexed: 12/14/2022]
Abstract
Mitochondria are responsible for the majority of oxygen consumption in cells, and thus represent a conceptually appealing site for cellular oxygen sensing. Over the past 40 years, a number of mechanisms to explain how mitochondria participate in oxygen sensing have been proposed. However, no consensus has been reached regarding how mitochondria could regulate transcriptional and post-translational responses to hypoxia. Nevertheless, a growing body of data continues to implicate a role for increased reactive oxygen species (ROS) signals from the electron transport chain (ETC) in triggering responses to hypoxia in diverse cell types. The present article reviews our progress in understanding this field and considers recent advances that provide new insight, helping to lift the fog from this complex topic.
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Affiliation(s)
- Gregory B Waypa
- Department of Pediatrics, Division of Neonatology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Kimberly A Smith
- Department of Pediatrics, Division of Neonatology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Paul T Schumacker
- Department of Pediatrics, Division of Neonatology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA.
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130
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López-Barneo J, González-Rodríguez P, Gao L, Fernández-Agüera MC, Pardal R, Ortega-Sáenz P. Oxygen sensing by the carotid body: mechanisms and role in adaptation to hypoxia. Am J Physiol Cell Physiol 2016; 310:C629-42. [PMID: 26764048 DOI: 10.1152/ajpcell.00265.2015] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Oxygen (O2) is fundamental for cell and whole-body homeostasis. Our understanding of the adaptive processes that take place in response to a lack of O2(hypoxia) has progressed significantly in recent years. The carotid body (CB) is the main arterial chemoreceptor that mediates the acute cardiorespiratory reflexes (hyperventilation and sympathetic activation) triggered by hypoxia. The CB is composed of clusters of cells (glomeruli) in close contact with blood vessels and nerve fibers. Glomus cells, the O2-sensitive elements in the CB, are neuron-like cells that contain O2-sensitive K(+)channels, which are inhibited by hypoxia. This leads to cell depolarization, Ca(2+)entry, and the release of transmitters to activate sensory fibers terminating at the respiratory center. The mechanism whereby O2modulates K(+)channels has remained elusive, although several appealing hypotheses have been postulated. Recent data suggest that mitochondria complex I signaling to membrane K(+)channels plays a fundamental role in acute O2sensing. CB activation during exposure to low Po2is also necessary for acclimatization to chronic hypoxia. CB growth during sustained hypoxia depends on the activation of a resident population of stem cells, which are also activated by transmitters released from the O2-sensitive glomus cells. These advances should foster further studies on the role of CB dysfunction in the pathogenesis of highly prevalent human diseases.
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Affiliation(s)
- José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Patricia González-Rodríguez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Lin Gao
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - M Carmen Fernández-Agüera
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Ricardo Pardal
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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131
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Buckler KJ, Turner PJ. Functional Properties of Mitochondria in the Type-1 Cell and Their Role in Oxygen Sensing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 860:69-80. [PMID: 26303469 DOI: 10.1007/978-3-319-18440-1_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The identity of the oxygen sensor in arterial chemoreceptors has been the subject of much speculation. One of the oldest hypotheses is that oxygen is sensed through oxidative phosphorylation. There is a wealth of data demonstrating that arterial chemoreceptors are excited by inhibitors of oxidative phosphorylation. These compounds mimic the effects of hypoxia inhibiting TASK1/3 potassium channels causing membrane depolarisation calcium influx and neurosecretion. The TASK channels of Type-I cells are also sensitive to cytosolic MgATP. The existence of a metabolic signalling pathway in Type-1 cells is thus established; the contentious issue is whether this pathway is also used for acute oxygen sensing. The main criticism is that because cytochrome oxidase has a high affinity for oxygen (P50 ≈ 0.2 mmHg) mitochondrial metabolism should be insensitive to physiological hypoxia. This argument is however predicated on the assumption that chemoreceptor mitochondria are analogous to those of other tissues. We have however obtained new evidence to support the hypothesis that type-1 cell mitochondria are not like those of other cells in that they have an unusually low affinity for oxygen (Mills E, Jobsis FF, J Neurophysiol 35(4):405-428, 1972; Duchen MR, Biscoe TJ, J Physiol 450:13-31, 1992a). Our data confirm that mitochondrial membrane potential, NADH, electron transport and cytochrome oxidase activity in the Type-1 cell are all highly sensitive to hypoxia. These observations not only provide exceptionally strong support for the metabolic hypothesis but also reveal an unknown side of mitochondrial behaviour.
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Affiliation(s)
- Keith J Buckler
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK,
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132
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Heinonen IHA, Boushel R, Kalliokoski KK. The Circulatory and Metabolic Responses to Hypoxia in Humans - With Special Reference to Adipose Tissue Physiology and Obesity. Front Endocrinol (Lausanne) 2016; 7:116. [PMID: 27621722 PMCID: PMC5002918 DOI: 10.3389/fendo.2016.00116] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 08/10/2016] [Indexed: 01/07/2023] Open
Abstract
Adipose tissue metabolism and circulation play an important role in human health. It is well-known that adipose tissue mass is increased in response to excess caloric intake leading to obesity and further to local hypoxia and inflammatory signaling. Acute exercise increases blood supply to adipose tissue and mobilization of fat stores for energy. However, acute exercise during systemic hypoxia reduces subcutaneous blood flow in healthy young subjects, but the response in overweight or obese subjects remains to be investigated. Emerging evidence also indicates that exercise training during hypoxic exposure may provide additive benefits with respect to many traditional cardiovascular risk factors as compared to exercise performed in normoxia, but unfavorable effects of hypoxia have also been documented. These topics will be covered in this brief review dealing with hypoxia and adipose tissue physiology.
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Affiliation(s)
- Ilkka H. A. Heinonen
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Clinical Physiology and Nuclear Medicine, University of Turku, Turku, Finland
- Division of Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
- *Correspondence: Ilkka H. A. Heinonen,
| | - Robert Boushel
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
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133
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Archer SL. Acquired Mitochondrial Abnormalities, Including Epigenetic Inhibition of Superoxide Dismutase 2, in Pulmonary Hypertension and Cancer: Therapeutic Implications. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 903:29-53. [PMID: 27343087 DOI: 10.1007/978-1-4899-7678-9_3] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
There is no cure for non-small-cell lung cancer (NSCLC) or pulmonary arterial hypertension (PAH). Therapies lack efficacy and/or are toxic, reflecting a failure to target disease abnormalities that are distinct from processes vital to normal cells. NSCLC and PAH share reversible mitochondrial-metabolic abnormalities which may offer selective therapeutic targets. The following mutually reinforcing, mitochondrial abnormalities favor proliferation, impair apoptosis, and are relatively restricted to PAH and cancer cells: (1) Epigenetic silencing of superoxide dismutase-2 (SOD2) by methylation of CpG islands creates a pseudohypoxic redox environment that causes normoxic activation of hypoxia inducible factor (HIF-1α). (2) HIF-1α increases expression of pyruvate dehydrogenase kinase (PDK), which impairs oxidative metabolism and promotes a glycolytic metabolic state. (3) Mitochondrial fragmentation, partially due to mitofusin-2 downregulation, promotes proliferation. This review focuses on the recent discovery that decreased expression of SOD2, a putative tumor-suppressor gene and the major source of H2O2, results from hypermethylation of CpG islands. In cancer and PAH hypermethylation of a site in the enhancer region of intron 2 inhibits SOD2 transcription. In normal PASMC, SOD2 siRNA decreases H2O2 and activates HIF-1α. In PAH, reduced SOD2 expression decreases H2O2, reduces the cytosol and thereby activates HIF-1α. This causes a glycolytic shift in metabolism and increases the proliferation/apoptosis ratio by downregulating Kv1.5 channels, increasing cytosolic calcium, and inhibiting caspases. The DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine, which restores SOD2 expression, corrects the proliferation/apoptosis imbalance in PAH and cancer cells. The specificity of PAH for lung vessels may relate to the selective upregulation of DNA methyltransferases that mediate CpG methylation in PASMC (DNA MT-1A and -3B). SOD2 augmentation inactivates HIF-1α in PAH PASMC and therapy with the SOD mimetic, MnTBAP, regresses experimental PAH. In conclusion, cancer and PAH share acquired mitochondrial abnormalities that increase proliferation and inhibit apoptosis, suggesting new therapeutic targets.
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Affiliation(s)
- Stephen L Archer
- Head Department of Medicine, Queen's University Program Medical Director KGH, HD, SMOL Etherington Hall, Room 3041 94 Stuart St., Kingston, Ontario, Canada, K7L 3N6.
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134
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Hirota K. Involvement of hypoxia-inducible factors in the dysregulation of oxygen homeostasis in sepsis. Cardiovasc Hematol Disord Drug Targets 2015; 15:29-40. [PMID: 25567333 PMCID: PMC4435091 DOI: 10.2174/1871529x15666150108115553] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 09/20/2014] [Accepted: 10/10/2014] [Indexed: 12/14/2022]
Abstract
Sepsis is a state of infection with serious systemic manifestations, and if severe enough, can be associated with multiple organ dysfunction and systemic hypotension, which can cause tissues to be hypoxic. Inflammation, as part of the multifaceted biological response to injurious stimuli, such as pathogens or damaged tissues and cells, underlies these biological processes. Prolonged and persistent inflammation, also known as chronic inflammation, results in progressive alteration in the various types of cells at the site of inflammation and is characterized by the simultaneous destruction and healing of tissue during the process. Tissue hypoxia during inflammation is not just a simple bystander process, but can considerably affect the development or attenuation of inflammation by causing the regulation of hypoxia-dependent gene expression. Indeed, the study of transcriptionally regulated tissue adaptation to hypoxia requires intense investigation to help control hypoxia-induced inflammation and organ failure. In this review, I have described the pathophysiology of sepsis with respect to oxygen metabolism and expression of hypoxia-inducible factor 1.
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Affiliation(s)
- Kiichi Hirota
- Department of Anesthesiology, Kansai Medical University, 2-3-1 Shin-Machi, Hirakata, Osaka 573-1191, Japan.
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135
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Mori Y, Takahashi N, Ogawa N, Gudermann T. Oxygen physiology: sensors and ion channels. Pflugers Arch 2015; 468:1-2. [PMID: 26590926 PMCID: PMC4700094 DOI: 10.1007/s00424-015-1762-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 11/16/2015] [Indexed: 01/05/2023]
Affiliation(s)
- Yasuo Mori
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, 615-8510, Japan. .,Laboratory of Environmental Systems Biology, Department of Technology and Ecology, Hall of Global Environmental Studies, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
| | - Nobuaki Takahashi
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, 615-8510, Japan.,Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Nozomi Ogawa
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto, 615-8510, Japan
| | - Thomas Gudermann
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians University, Munich, Germany.,Comprehensive Pneumology Center Munich (CPC-M), German Center for Lung Research, Munich, Germany.,DZHK (German Centre for Cardiovascular Research), Munich Heart Alliance, Munich, Germany
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136
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Fernández-Agüera MC, Gao L, González-Rodríguez P, Pintado CO, Arias-Mayenco I, García-Flores P, García-Pergañeda A, Pascual A, Ortega-Sáenz P, López-Barneo J. Oxygen Sensing by Arterial Chemoreceptors Depends on Mitochondrial Complex I Signaling. Cell Metab 2015; 22:825-37. [PMID: 26437605 DOI: 10.1016/j.cmet.2015.09.004] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 07/17/2015] [Accepted: 09/08/2015] [Indexed: 12/30/2022]
Abstract
O2 sensing is essential for mammalian homeostasis. Peripheral chemoreceptors such as the carotid body (CB) contain cells with O2-sensitive K(+) channels, which are inhibited by hypoxia to trigger fast adaptive cardiorespiratory reflexes. How variations of O2 tension (PO2) are detected and the mechanisms whereby these changes are conveyed to membrane ion channels have remained elusive. We have studied acute O2 sensing in conditional knockout mice lacking mitochondrial complex I (MCI) genes. We inactivated Ndufs2, which encodes a protein that participates in ubiquinone binding. Ndufs2-null mice lose the hyperventilatory response to hypoxia, although they respond to hypercapnia. Ndufs2-deficient CB cells have normal functions and ATP content but are insensitive to changes in PO2. Our data suggest that chemoreceptor cells have a specialized succinate-dependent metabolism that induces an MCI state during hypoxia, characterized by the production of reactive oxygen species and accumulation of reduced pyridine nucleotides, which signal neighboring K(+) channels.
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Affiliation(s)
- M Carmen Fernández-Agüera
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain; Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Avenida Sánchez Pizjuan, 4, 41009 Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain
| | - Lin Gao
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain; Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Avenida Sánchez Pizjuan, 4, 41009 Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain
| | - Patricia González-Rodríguez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain; Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Avenida Sánchez Pizjuan, 4, 41009 Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain
| | - C Oscar Pintado
- Centro de Producción y Experimentación Animal, Universidad de Sevilla, Calle San Fernando, 4, 41004 Seville, Spain
| | - Ignacio Arias-Mayenco
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain; Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Avenida Sánchez Pizjuan, 4, 41009 Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain
| | - Paula García-Flores
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain
| | - Antonio García-Pergañeda
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain
| | - Alberto Pascual
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain
| | - Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain; Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Avenida Sánchez Pizjuan, 4, 41009 Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain
| | - José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain; Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Avenida Sánchez Pizjuan, 4, 41009 Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot, s/n, 41013 Seville, Spain.
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137
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Suzuki N, Yamamoto M. Roles of renal erythropoietin-producing (REP) cells in the maintenance of systemic oxygen homeostasis. Pflugers Arch 2015; 468:3-12. [PMID: 26452589 DOI: 10.1007/s00424-015-1740-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 09/27/2015] [Accepted: 09/29/2015] [Indexed: 12/13/2022]
Abstract
Erythropoietic induction is critical for enhancing the efficiency of oxygen delivery during the chronic phase of the systemic hypoxia response. The erythroid growth factor erythropoietin (Epo) triggers the erythropoietic induction through the activation of erythroid genes related to cell survival, differentiation, and iron metabolism. Because Epo is produced in renal Epo-producing (REP) cells in a hypoxia-inducible manner, REP cells serve as a control center for the systemic hypoxia response. In fact, the loss of Epo production in REP cells causes chronic severe anemia in genetically modified mice, and REP cell-specific inactivation of PHD2 (prolyl-hydroxylase domain enzyme 2) results in erythrocytosis via overexpression of the Epo gene due to the constitutive activation of HIF2α (hypoxia-inducible transcription factor 2α). REP cells are located in the interstitial spaces between renal tubules and capillaries, where the oxygen supply is low but oxygen consumption is high, for the highly sensitive detection of decreased oxygen supplies to the body. Under disease conditions, REP cells transform to myofibroblasts and lose their Epo-producing ability. Therefore, elucidation of Epo gene regulation and REP cell features directly contributes to understanding the pathology of chronic kidney disease. To further analyze REP cells, we introduce a newly established mouse line in which REP cells are efficiently labeled with fluorescent protein.
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Affiliation(s)
- Norio Suzuki
- Division of Interdisciplinary Medical Science, Center for Oxygen Medicine, United Centers for Advanced Research and Translational Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-Machi, Aoba-ku, Sendai, 980-8575, Japan.
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, 2-1 Seiryo-Machi, Aoba-ku, Sendai, 980-8575, Japan
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138
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Dunham-Snary KJ, Hong ZG, Xiong PY, Del Paggio JC, Herr JE, Johri AM, Archer SL. A mitochondrial redox oxygen sensor in the pulmonary vasculature and ductus arteriosus. Pflugers Arch 2015; 468:43-58. [PMID: 26395471 DOI: 10.1007/s00424-015-1736-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 09/09/2015] [Accepted: 09/15/2015] [Indexed: 12/18/2022]
Abstract
The mammalian homeostatic oxygen sensing system (HOSS) initiates changes in vascular tone, respiration, and neurosecretion that optimize oxygen uptake and tissue oxygen delivery within seconds of detecting altered environmental or arterial PO2. The HOSS includes carotid body type 1 cells, adrenomedullary cells, neuroepithelial bodies, and smooth muscle cells (SMCs) in pulmonary arteries (PAs), ductus arteriosus (DA), and fetoplacental arteries. Hypoxic pulmonary vasoconstriction (HPV) optimizes ventilation-perfusion matching. In utero, HPV diverts placentally oxygenated blood from the non-ventilated lung through the DA. At birth, increased alveolar and arterial oxygen tension dilates the pulmonary vasculature and constricts the DA, respectively, thereby transitioning the newborn to an air-breathing organism. Though modulated by endothelial-derived relaxing and constricting factors, O2 sensing is intrinsic to PASMCs and DASMCs. Within the SMC's dynamic mitochondrial network, changes in PO2 alter the reduction-oxidation state of redox couples (NAD(+)/NADH, NADP(+)/NADPH) and the production of reactive oxygen species, ROS (e.g., H2O2), by complexes I and III of the electron transport chain (ETC). ROS and redox couples regulate ion channels, transporters, and enzymes, changing intracellular calcium [Ca(2+)]i and calcium sensitivity and eliciting homeostatic responses to hypoxia. In PASMCs, hypoxia inhibits ROS production and reduces redox couples, thereby inhibiting O2-sensitive voltage-gated potassium (Kv) channels, depolarizing the plasma membrane, activating voltage-gated calcium channels (CaL), increasing [Ca(2+)]i, and causing vasoconstriction. In DASMCs, elevated PO2 causes mitochondrial fission, increasing ETC complex I activity and ROS production. The DASMC's downstream response to elevated PO2 (Kv channel inhibition, CaL activation, increased [Ca(2+)]i, and rho kinase activation) is similar to the PASMC's hypoxic response. Impaired O2 sensing contributes to human diseases, including pulmonary arterial hypertension and patent DA.
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Affiliation(s)
- Kimberly J Dunham-Snary
- Department of Medicine, Queen's University, Etherington Hall, Room 3041, 94 Stuart St, Kingston, ON, K7L 3N6, Canada
| | - Zhigang G Hong
- Department of Medicine, Queen's University, Etherington Hall, Room 3041, 94 Stuart St, Kingston, ON, K7L 3N6, Canada
| | - Ping Y Xiong
- Department of Medicine, Queen's University, Etherington Hall, Room 3041, 94 Stuart St, Kingston, ON, K7L 3N6, Canada
| | - Joseph C Del Paggio
- Department of Medicine, Queen's University, Etherington Hall, Room 3041, 94 Stuart St, Kingston, ON, K7L 3N6, Canada
| | - Julia E Herr
- Department of Medicine, Queen's University, Etherington Hall, Room 3041, 94 Stuart St, Kingston, ON, K7L 3N6, Canada
| | - Amer M Johri
- Department of Medicine, Queen's University, Etherington Hall, Room 3041, 94 Stuart St, Kingston, ON, K7L 3N6, Canada
| | - Stephen L Archer
- Department of Medicine, Queen's University, Etherington Hall, Room 3041, 94 Stuart St, Kingston, ON, K7L 3N6, Canada.
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139
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Carotid body oxygen sensing and adaptation to hypoxia. Pflugers Arch 2015; 468:59-70. [DOI: 10.1007/s00424-015-1734-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 09/01/2015] [Accepted: 09/04/2015] [Indexed: 10/23/2022]
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140
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Balanos GM, Pugh K, Frise MC, Dorrington KL. Exaggerated pulmonary vascular response to acute hypoxia in older men. Exp Physiol 2015; 100:1187-98. [DOI: 10.1113/ep085403] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/03/2015] [Indexed: 12/16/2022]
Affiliation(s)
- George M. Balanos
- School of Sport, Exercise and Rehabilitation Sciences; University of Birmingham; Edgbaston Birmingham UK
| | - Keith Pugh
- School of Sport, Exercise and Rehabilitation Sciences; University of Birmingham; Edgbaston Birmingham UK
| | - Matthew C. Frise
- Department of Physiology, Anatomy & Genetics; University of Oxford; Oxford UK
| | - Keith L. Dorrington
- Department of Physiology, Anatomy & Genetics; University of Oxford; Oxford UK
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141
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Abstract
Pulmonary neuroendocrine cells (PNEC) are widely distributed throughout the airway mucosa of mammalian lung as solitary cells and as distinctive innervated clusters, neuroepithelial bodies (NEB). These cells differentiate early during lung development and are more prominent in fetal/neonatal lungs compared to adults. PNEC/NEB cells produce biogenic amine (serotonin) and a variety of peptides (i.e., bombesin) involved in regulation of lung function. During the perinatal period, NEB are thought to function as airway O(2)/CO(2) sensors. Increased numbers of PNEC/NEBs have been observed in a variety of perinatal and postnatal lung disorders. Recent advances in cellular and molecular biology of these cells, as they relate to perinatal and postnatal lung disorders associated with PNEC/NEB cell hyperplasia are reviewed and their possible role in pulmonary pathobiology discussed (WC 125).
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Affiliation(s)
- Ernest Cutz
- Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, 555 University Ave, Toronto, Ontario, Canada M5G1x8; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
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142
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Macías D, Fernández-Agüera MC, Bonilla-Henao V, López-Barneo J. Deletion of the von Hippel-Lindau gene causes sympathoadrenal cell death and impairs chemoreceptor-mediated adaptation to hypoxia. EMBO Mol Med 2015; 6:1577-92. [PMID: 25385837 PMCID: PMC4287976 DOI: 10.15252/emmm.201404153] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Mutations of the von Hippel–Lindau (VHL) gene are associated with pheochromocytomas and paragangliomas, but the role of VHL in sympathoadrenal homeostasis is unknown. We generated mice lacking Vhl in catecholaminergic cells. They exhibited atrophy of the carotid body (CB), adrenal medulla, and sympathetic ganglia. Vhl-null animals had an increased number of adult CB stem cells, although the survival of newly generated neuron-like glomus cells was severely compromised. The effects of Vhl deficiency were neither prevented by pharmacological inhibition of prolyl hydroxylases or selective genetic down-regulation of prolyl hydroxylase-3, nor phenocopied by hypoxia inducible factor overexpression. Vhl-deficient animals appeared normal in normoxia but survived for only a few days in hypoxia, presenting with pronounced erythrocytosis, pulmonary edema, and right cardiac hypertrophy. Therefore, in the normal sympathoadrenal setting, Vhl deletion does not give rise to tumors but impairs development and plasticity of the peripheral O2-sensing system required for survival in hypoxic conditions.
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Affiliation(s)
- David Macías
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Mary Carmen Fernández-Agüera
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Victoria Bonilla-Henao
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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143
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Mori Y, Takahashi N, Polat OK, Kurokawa T, Takeda N, Inoue M. Redox-sensitive transient receptor potential channels in oxygen sensing and adaptation. Pflugers Arch 2015; 468:85-97. [PMID: 26149285 PMCID: PMC4700073 DOI: 10.1007/s00424-015-1716-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/22/2015] [Indexed: 12/14/2022]
Abstract
Regulation of ion channels is central to the mechanisms that underlie immediate acute physiological responses to changes in the availability of molecular oxygen (O2). A group of cation-permeable channels that are formed by transient receptor potential (TRP) proteins have been characterized as exquisite sensors of redox reactive species and as efficient actuators of electric/ionic signals in vivo. In this review, we first discuss how redox-sensitive TRP channels such as TRPA1 have recently emerged as sensors of the relatively inert oxidant O2. With regard to the physiological significance of O2 sensor TRP channels, vagal TRPA1 channels are mainly discussed with respect to their role in respiratory regulation in comparison with canonical pathways in glomus cells of the carotid body, which is a well-established O2-sensing organ. TRPM7 channels are discussed regarding hypoxia-sensing function in ischemic cell death. Also, ubiquitous expression of TRPA1 and TRPM7 together with their physiological relevance in the body is examined. Finally, based upon these studies on TRP channels, we propose a hypothesis of “O2 remodeling.” The hypothesis is that cells detect deviation of O2 availability from appropriate levels via sensors and adjust local O2 environments in vivo by controlling supply and consumption of O2 via pathways comprising cellular signals and transcription factors downstream of sensors, which consequently optimize physiological functions. This new insight into O2 adaptation through ion channels, particularly TRPs, may foster a paradigm shift in our understanding in the biological significance of O2.
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Affiliation(s)
- Yasuo Mori
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
- Laboratory of Environmental Systems Biology, Department of Technology and Ecology, Hall of Global Environmental Studies, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
| | - Nobuaki Takahashi
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Onur Kerem Polat
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Tatsuki Kurokawa
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Norihiko Takeda
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Masahiro Inoue
- Department of Biochemistry, Osaka Medical Center for Cancer and Cardiovascular Diseases, Higashinari-ku, Osaka, 537-8511, Japan
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144
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Abstract
Pulmonary arterial hypertension is a progressive and debilitating disorder with an associated high morbidity and mortality rate. Significant advances in our understanding of the epidemiology, pathogenesis, and pathophysiology of pulmonary hypertension have occurred over the past several decades. This has allowed the development of new therapeutic options in this disease. Today, our selection of therapeutic modalities is broader, including calcium channel blockers, prostanoids, endothelin receptor antagonists, phosphodiesterase inhibitors, and soluble guanylate cyclase stimulators, but the disease remains fatal. This underscores the need for a continued search for novel therapies. Several potential pharmacologic agents for the treatment of pulmonary arterial hypertension are under clinical development and some promising results with these treatments have been reported. These agents include rho-kinase inhibitors, long-acting nonprostanoid prostacyclin receptor agonists, tyrosine protein kinase inhibitors, endothelial nitric oxide synthase couplers, synthetically produced vasoactive intestinal peptide, antagonists of the 5-HT2 receptors, and others. This article will review several of these promising new therapies and will discuss the current evidence regarding their potential benefit in pulmonary arterial hypertension.
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145
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Mishra A, Kohli S, Dua S, Thinlas T, Mohammad G, Pasha MAQ. Genetic differences and aberrant methylation in the apelin system predict the risk of high-altitude pulmonary edema. Proc Natl Acad Sci U S A 2015; 112:6134-6139. [PMID: 25918383 PMCID: PMC4434746 DOI: 10.1073/pnas.1422759112] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Hypoxia-inducible factor stimulates the expression of apelin, a potent vasodilator, in response to reduced blood arterial oxygen saturation. However, aberrations in the apelin system impair pulmonary vascular function, potentially resulting in the development of high-altitude (HA)-related disorders. This study aimed to elucidate the genetic and epigenetic regulation of apelin, apelin receptor (APLNR), and endothelial nitric oxide synthase (NOS3) in HA adaptation and HA pulmonary edema (HAPE). A genome-wide association study and sequencing identified variants of apelin, APLNR, and NOS3 that were validated in a larger sample size of HAPE-patients (HAPE-p), HAPE-free controls (HAPE-f), and healthy highland natives (HLs). Apelin-13 and nitrite levels and apelin and NOS3 expression were down-regulated in HAPE-p (P < 0.001). Among the several studied polymorphisms, apelin rs3761581, rs2235312, and rs3115757; APLNR rs11544374 and rs2282623; and NOS3 4b/4a, rs1799983, and rs7830 were associated with HAPE (P < 0.03). The risk allele rs3761581G was associated with a 58.6% reduction in gene expression (P = 0.017), and the risk alleles rs3761581G and rs2235312T were associated with low levels of apelin-13 and nitrite (P < 0.05). The latter two levels decreased further when both of these risk alleles were present in the patients (P < 0.05). Methylation of the apelin CpG island was significantly higher in HAPE-p at 11.92% than in HAPE-f and HLs at ≤ 7.1% (P < 0.05). Moreover, the methylation effect was 9% stronger in the 5' UTR and was associated with decreased apelin expression and apelin-13 levels. The rs3761581 and rs2235312 polymorphisms and methylation of the CpG island influence the expression of apelin in HAPE.
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Affiliation(s)
- Aastha Mishra
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi 110007, India; Department of Biotechnology, University of Pune, Pune 411007, India
| | - Samantha Kohli
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi 110007, India; Academy of Scientific and Innovative Research, New Delhi 110025, India; and
| | - Sanchi Dua
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi 110007, India
| | - Tashi Thinlas
- Department of Medicine, Sonam Norboo Memorial Hospital, Leh, Ladakh, Jammu, and Kashmir 194101, India
| | - Ghulam Mohammad
- Department of Medicine, Sonam Norboo Memorial Hospital, Leh, Ladakh, Jammu, and Kashmir 194101, India
| | - M A Qadar Pasha
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, Delhi 110007, India;
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146
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Fan Z, Liu B, Zhang S, Liu H, Li Y, Wang D, Liu Y, Li J, Wang N, Liu Y, Zhang B. YM155, a selective survivin inhibitor, reverses chronic hypoxic pulmonary hypertension in rats via upregulating voltage-gated potassium channels. Clin Exp Hypertens 2015; 37:381-7. [PMID: 25856227 DOI: 10.3109/10641963.2014.987390] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
To test the hypothesis that chronic hypoxic pulmonary hypertension (CH-PH) is associated with increased survivin and decreased voltage-gated potassium (KV) channels expression in pulmonary arteries, rats were randomized as: normoxia (N); normoxia + YM155, survivin suppressor (NY); hypoxia (H); hypoxia + YM155 (HY). HY group had significantly reduced pulmonary arterial pressure, right ventricular weight and right ventricular hypertrophy compared with H group. Survivin mRNA and protein were detected in pulmonary arteries of rats with CH-PH, but not rats without CH-PH. YM155 downregulated survivin protein and mRNA. KV channel expression and activity were upregulated after YM155 treatment. Survivin may play a role in the pathogenesis of CH-PH.
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Affiliation(s)
- Zaiwen Fan
- Department of Respiratory Medicine, General Hospital of PLA Air Force , Beijing , China
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147
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Veit F, Pak O, Brandes RP, Weissmann N. Hypoxia-dependent reactive oxygen species signaling in the pulmonary circulation: focus on ion channels. Antioxid Redox Signal 2015; 22:537-52. [PMID: 25545236 PMCID: PMC4322788 DOI: 10.1089/ars.2014.6234] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
SIGNIFICANCE An acute lack of oxygen in the lung causes hypoxic pulmonary vasoconstriction, which optimizes gas exchange. In contrast, chronic hypoxia triggers a pathological vascular remodeling causing pulmonary hypertension, and ischemia can cause vascular damage culminating in lung edema. RECENT ADVANCES Regulation of ion channel expression and gating by cellular redox state is a widely accepted mechanism; however, it remains a matter of debate whether an increase or a decrease in reactive oxygen species (ROS) occurs under hypoxic conditions. Ion channel redox regulation has been described in detail for some ion channels, such as Kv channels or TRPC6. However, in general, information on ion channel redox regulation remains scant. CRITICAL ISSUES AND FUTURE DIRECTIONS In addition to the debate of increased versus decreased ROS production during hypoxia, we aim here at describing and deciphering why different oxidants, under different conditions, can cause both activation and inhibition of channel activity. While the upstream pathways affecting channel gating are often well described, we need a better understanding of redox protein modifications to be able to determine the complexity of ion channel redox regulation. Against this background, we summarize the current knowledge on hypoxia-induced ROS-mediated ion channel signaling in the pulmonary circulation.
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Affiliation(s)
- Florian Veit
- 1 Excellence Cluster Cardiopulmonary System (ECCPS), Universities of Giessen and Marburg Lung Center (UGMLC), German Center for Lung Research (DZL) , Giessen, Germany
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148
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Ryan J, Dasgupta A, Huston J, Chen KH, Archer SL. Mitochondrial dynamics in pulmonary arterial hypertension. J Mol Med (Berl) 2015; 93:229-42. [PMID: 25672499 DOI: 10.1007/s00109-015-1263-5] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/27/2015] [Accepted: 02/02/2015] [Indexed: 12/31/2022]
Abstract
Pulmonary arterial hypertension (PAH) is an idiopathic cardiopulmonary disease characterized by obstruction of small pulmonary arteries. Vascular obstruction is the consequence of excessive proliferation and apoptosis resistance of vascular cells, as well as inflammation, thrombosis, and vasoconstriction. Vascular obstruction increases the afterload faced by the right ventricle (RV), leading to RV failure. The proliferative, obstructive vasculopathy of PAH shares several mitochondrial abnormalities with cancer, notably a shift to aerobic glycolysis and mitochondrial fragmentation. Mitochondria in the pulmonary artery smooth muscle cell (PASMC) normally serve as oxygen sensors. In PAH, acquired mitochondrial abnormalities, including epigenetic silencing of superoxide dismutase (SOD2), disrupt oxygen sensing creating a pseudo-hypoxic environment characterized by normoxic activation of hypoxia-inducible factor-1α (HIF-1α). The resulting metabolic shift to aerobic glycolysis (the Warburg phenomenon) reflects inhibition of pyruvate dehydrogenase by pyruvate dehydrogenase kinases. In addition, altered mitochondrial dynamics result in mitochondrial fragmentation. The molecular basis of this structural change includes upregulation and activation of fission mediators, notably dynamin-related protein 1 (DRP-1), and downregulation of fusion mediators, especially mitofusin-2 (MFN2). These pathogenic mitochondrial abnormalities offer new therapeutic targets. Inhibition of mitotic fission or enhancement of fusion in PAH PASMC slows cell proliferation, causes cell cycle arrest, and induces apoptosis. DRP-1 inhibition or MFN2 gene therapy can regress PAH in experimental models of PAH. This review focuses on the etiology of mitochondrial fragmentation in PAH and explores the therapeutic implications of mitochondrial dynamics in the pulmonary vasculature and RV.
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Affiliation(s)
- John Ryan
- Division of Cardiovascular Medicine, Department of Medicine, University of Utah, Salt Lake City, UT, USA
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149
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TASK channels in arterial chemoreceptors and their role in oxygen and acid sensing. Pflugers Arch 2015; 467:1013-25. [PMID: 25623783 PMCID: PMC4428840 DOI: 10.1007/s00424-015-1689-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 01/06/2015] [Accepted: 01/07/2015] [Indexed: 01/05/2023]
Abstract
Arterial chemoreceptors play a vital role in cardiorespiratory control by providing the brain with information regarding blood oxygen, carbon dioxide, and pH. The main chemoreceptor, the carotid body, is composed of sensory (type 1) cells which respond to hypoxia or acidosis with a depolarising receptor potential which in turn activates voltage-gated calcium entry, neurosecretion and excitation of adjacent afferent nerves. The receptor potential is generated by inhibition of Twik-related acid-sensitive K(+) channel 1 and 3 (TASK1/TASK3) heterodimeric channels which normally maintain the cells' resting membrane potential. These channels are thought to be directly inhibited by acidosis. Oxygen sensitivity, however, probably derives from a metabolic signalling pathway. The carotid body, isolated type 1 cells, and all forms of TASK channel found in the type 1 cell, are highly sensitive to inhibitors of mitochondrial metabolism. Moreover, type1 cell TASK channels are activated by millimolar levels of MgATP. In addition to their role in the transduction of chemostimuli, type 1 cell TASK channels have also been implicated in the modulation of chemoreceptor function by a number of neurocrine/paracrine signalling molecules including adenosine, GABA, and serotonin. They may also be instrumental in mediating the depression of the acute hypoxic ventilatory response that occurs with some general anaesthetics. Modulation of TASK channel activity is therefore a key mechanism by which the excitability of chemoreceptors can be controlled. This is not only of physiological importance but may also offer a therapeutic strategy for the treatment of cardiorespiratory disorders that are associated with chemoreceptor dysfunction.
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Ortega-Sáenz P, Villadiego J, Pardal R, Toledo-Aral JJ, López-Barneo J. Neurotrophic Properties, Chemosensory Responses and Neurogenic Niche of the Human Carotid Body. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 860:139-52. [PMID: 26303476 DOI: 10.1007/978-3-319-18440-1_16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The carotid body (CB) is a polymodal chemoreceptor that triggers the hyperventilatory response to hypoxia necessary for the maintenance of O(2) homeostasis essential for the survival of organs such as the brain or heart. Glomus cells, the sensory elements in the CB, are also sensitive to hypercapnia, acidosis and, although less generally accepted, hypoglycemia. Current knowledge on CB function is mainly based on studies performed on lower mammals, but the information on the human CB is scant. Here we describe the structure, neurotrophic properties, and cellular responses to hypoxia and hypoglycemia of CBs dissected from human cadavers. The adult CB parenchyma contains clusters of chemosensitive glomus (type I) and sustentacular (type II) cells as well as nestin-positive progenitor cells. This organ also expresses high levels of the dopaminotrophic glial cell line-derived neurotrophic factor (GDNF). GDNF production and the number of progenitor and glomus cells were preserved in the CBs of human subjects of advanced age. As reported for other mammalian species, glomus cells responded to hypoxia by external Ca(2+)-dependent increase of cytosolic [Ca(2+)] and quantal catecholamine release. Human glomus cells are also responsive to hypoglycemia and together the two stimuli, hypoxia and hypoglycemia, can potentiate each other's effects. The chemo-sensory responses of glomus cells are also preserved at an advanced age. Interestingly, a neurogenic niche similar to that recently described in rodents is also preserved in the adult human CB. These new data on the cellular and molecular physiology of the CB pave the way for future pathophysiological studies involving this organ in humans.
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Affiliation(s)
- Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Avenida Manuel Siurot s/n, 41013, Seville, Spain
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