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Geng Y, Hu Y, Zhang F, Tuo Y, Ge R, Bai Z. Mitochondria in hypoxic pulmonary hypertension, roles and the potential targets. Front Physiol 2023; 14:1239643. [PMID: 37645564 PMCID: PMC10461481 DOI: 10.3389/fphys.2023.1239643] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 08/03/2023] [Indexed: 08/31/2023] Open
Abstract
Mitochondria are the centrol hub for cellular energy metabolisms. They regulate fuel metabolism by oxygen levels, participate in physiological signaling pathways, and act as oxygen sensors. Once oxygen deprived, the fuel utilizations can be switched from mitochondrial oxidative phosphorylation to glycolysis for ATP production. Notably, mitochondria can also adapt to hypoxia by making various functional and phenotypes changes to meet the demanding of oxygen levels. Hypoxic pulmonary hypertension is a life-threatening disease, but its exact pathgenesis mechanism is still unclear and there is no effective treatment available until now. Ample of evidence indicated that mitochondria play key factor in the development of hypoxic pulmonary hypertension. By hypoxia-inducible factors, multiple cells sense and transmit hypoxia signals, which then control the expression of various metabolic genes. This activation of hypoxia-inducible factors considered associations with crosstalk between hypoxia and altered mitochondrial metabolism, which plays an important role in the development of hypoxic pulmonary hypertension. Here, we review the molecular mechanisms of how hypoxia affects mitochondrial function, including mitochondrial biosynthesis, reactive oxygen homeostasis, and mitochondrial dynamics, to explore the potential of improving mitochondrial function as a strategy for treating hypoxic pulmonary hypertension.
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Affiliation(s)
- Yumei Geng
- Key Laboratory of High Altitude Medicine (Ministry of Education), Key Laboratory of Application and Foundation for High Altitude Medicine Research in Qinghai Province (Qinghai-Utah Joint Research Key Lab for High Altitude Medicine), Research Center for High Altitude Medicine, Qinghai University, Xining, China
- Department of Respiratory and Critical Care Medicine, Qinghai Provincial People’s Hospital, Xining, China
| | - Yu Hu
- Department of Pharmacy, Qinghai Provincial Traffic Hospital, Xining, China
| | - Fang Zhang
- Department of Respiratory and Critical Care Medicine, Qinghai Provincial People’s Hospital, Xining, China
| | - Yajun Tuo
- Department of Respiratory and Critical Care Medicine, Qinghai Provincial People’s Hospital, Xining, China
| | - Rili Ge
- Key Laboratory of High Altitude Medicine (Ministry of Education), Key Laboratory of Application and Foundation for High Altitude Medicine Research in Qinghai Province (Qinghai-Utah Joint Research Key Lab for High Altitude Medicine), Research Center for High Altitude Medicine, Qinghai University, Xining, China
| | - Zhenzhong Bai
- Key Laboratory of High Altitude Medicine (Ministry of Education), Key Laboratory of Application and Foundation for High Altitude Medicine Research in Qinghai Province (Qinghai-Utah Joint Research Key Lab for High Altitude Medicine), Research Center for High Altitude Medicine, Qinghai University, Xining, China
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2
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Hernansanz-Agustín P, Enríquez JA. Alternative respiratory oxidases to study the animal electron transport chain. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148936. [PMID: 36395975 DOI: 10.1016/j.bbabio.2022.148936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/05/2022] [Accepted: 11/06/2022] [Indexed: 11/16/2022]
Abstract
Oxidative phosphorylation is a common process to most organisms in which the main function is to generate an electrochemical gradient across the inner mitochondrial membrane (IMM) and to make energy available to the cell. However, plants, many fungi and some animals maintain non-energy conserving oxidases which serve as a bypass to coupled respiration. Namely, the alternative NADH:ubiquinone oxidoreductase NDI1, present in the complex I (CI)-lacking Saccharomyces cerevisiae, and the alternative oxidase, ubiquinol:oxygen oxidoreductase AOX, present in many organisms across different kingdoms. In the last few years, these alternative oxidases have been used to dissect previously indivisible processes in bioenergetics and have helped to discover, understand, and corroborate important processes in mitochondria. Here, we review how the use of alternative oxidases have contributed to the knowledge in CI stability, bioenergetics, redox biology, and the implications of their use in current and future research.
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Affiliation(s)
- Pablo Hernansanz-Agustín
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain; Centro de Investigaciones Biomédicas en Red en Fragilidad y Envejecimiento saludable (CIBERFES), 28029 Madrid, Spain.
| | - José Antonio Enríquez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain; Centro de Investigaciones Biomédicas en Red en Fragilidad y Envejecimiento saludable (CIBERFES), 28029 Madrid, Spain.
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3
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Moreno-Domínguez A, Colinas O, Smani T, Ureña J, López-Barneo J. Acute oxygen sensing by vascular smooth muscle cells. Front Physiol 2023; 14:1142354. [PMID: 36935756 PMCID: PMC10020353 DOI: 10.3389/fphys.2023.1142354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 02/21/2023] [Indexed: 03/06/2023] Open
Abstract
An adequate supply of oxygen (O2) is essential for most life forms on earth, making the delivery of appropriate levels of O2 to tissues a fundamental physiological challenge. When O2 levels in the alveoli and/or blood are low, compensatory adaptive reflexes are produced that increase the uptake of O2 and its distribution to tissues within a few seconds. This paper analyzes the most important acute vasomotor responses to lack of O2 (hypoxia): hypoxic pulmonary vasoconstriction (HPV) and hypoxic vasodilation (HVD). HPV affects distal pulmonary (resistance) arteries, with its homeostatic role being to divert blood to well ventilated alveoli to thereby optimize the ventilation/perfusion ratio. HVD is produced in most systemic arteries, in particular in the skeletal muscle, coronary, and cerebral circulations, to increase blood supply to poorly oxygenated tissues. Although vasomotor responses to hypoxia are modulated by endothelial factors and autonomic innervation, it is well established that arterial smooth muscle cells contain an acute O2 sensing system capable of detecting changes in O2 tension and to signal membrane ion channels, which in turn regulate cytosolic Ca2+ levels and myocyte contraction. Here, we summarize current knowledge on the nature of O2 sensing and signaling systems underlying acute vasomotor responses to hypoxia. We also discuss similarities and differences existing in O2 sensors and effectors in the various arterial territories.
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Affiliation(s)
- Alejandro Moreno-Domínguez
- 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), Madrid, Spain
| | - Olaia Colinas
- 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), Madrid, Spain
| | - Tarik Smani
- 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
| | - Juan Ureña
- 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
| | - 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), Madrid, Spain
- *Correspondence: José López-Barneo,
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4
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Pak O, Nolte A, Knoepp F, Giordano L, Pecina P, Hüttemann M, Grossman LI, Weissmann N, Sommer N. Mitochondrial oxygen sensing of acute hypoxia in specialized cells - Is there a unifying mechanism? BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148911. [PMID: 35988811 DOI: 10.1016/j.bbabio.2022.148911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Acclimation to acute hypoxia through cardiorespiratory responses is mediated by specialized cells in the carotid body and pulmonary vasculature to optimize systemic arterial oxygenation and thus oxygen supply to the tissues. Acute oxygen sensing by these cells triggers hyperventilation and hypoxic pulmonary vasoconstriction which limits pulmonary blood flow through areas of low alveolar oxygen content. Oxygen sensing of acute hypoxia by specialized cells thus is a fundamental pre-requisite for aerobic life and maintains systemic oxygen supply. However, the primary oxygen sensing mechanism and the question of a common mechanism in different specialized oxygen sensing cells remains unresolved. Recent studies unraveled basic oxygen sensing mechanisms involving the mitochondrial cytochrome c oxidase subunit 4 isoform 2 that is essential for the hypoxia-induced release of mitochondrial reactive oxygen species and subsequent acute hypoxic responses in both, the carotid body and pulmonary vasculature. This review compares basic mitochondrial oxygen sensing mechanisms in the pulmonary vasculature and the carotid body.
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Affiliation(s)
- Oleg Pak
- Justus Liebig University, Excellence Cluster Cardio-Pulmonary Institute (CPI), Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Anika Nolte
- Justus Liebig University, Excellence Cluster Cardio-Pulmonary Institute (CPI), Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Fenja Knoepp
- Justus Liebig University, Excellence Cluster Cardio-Pulmonary Institute (CPI), Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Luca Giordano
- Justus Liebig University, Excellence Cluster Cardio-Pulmonary Institute (CPI), Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Petr Pecina
- Laboratory of Bioenergetics, Institute of Physiology CAS, Prague, Czech Republic
| | - Maik Hüttemann
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, USA
| | - Lawrence I Grossman
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, USA
| | - Norbert Weissmann
- Justus Liebig University, Excellence Cluster Cardio-Pulmonary Institute (CPI), Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany
| | - Natascha Sommer
- Justus Liebig University, Excellence Cluster Cardio-Pulmonary Institute (CPI), Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany.
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5
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Oxygen regulation of breathing is abolished in mitochondrial complex III-deficient arterial chemoreceptors. Proc Natl Acad Sci U S A 2022; 119:e2202178119. [PMID: 36122208 PMCID: PMC9522341 DOI: 10.1073/pnas.2202178119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Oxygen sensing by chemoreceptor glomus cells in the carotid body plays an essential adaptive function in health and disease; however, the underlying mechanisms are not fully understood. Glomus cells survive genetic disruption of mitochondrial complex III, although this results in a functional disconnection between the distal and proximal components of the mitochondrial electron transport chain (ETC). These cells exhibit selective abolition of mitochondrial and cellular responsiveness to hypoxia, as well as altered systemic hyperventilation and acclimatization to hypoxia, indicating that acute oxygen-sensing and -signaling during hypoxia result from the integrated action of mitochondrial ETC components. The mitochondrial ETC emerges as a complex oxygen-sensing and -signaling system of potential pathophysiological relevance in maladaptive responses to hypoxia. Acute oxygen (O2) sensing is essential for adaptation of organisms to hypoxic environments or medical conditions with restricted exchange of gases in the lung. The main acute O2-sensing organ is the carotid body (CB), which contains neurosecretory chemoreceptor (glomus) cells innervated by sensory fibers whose activation by hypoxia elicits hyperventilation and increased cardiac output. Glomus cells have mitochondria with specialized metabolic and electron transport chain (ETC) properties. Reduced mitochondrial complex (MC) IV activity by hypoxia leads to production of signaling molecules (NADH and reactive O2 species) in MCI and MCIII that modulate membrane ion channel activity. We studied mice with conditional genetic ablation of MCIII that disrupts the ETC in the CB and other catecholaminergic tissues. Glomus cells survived MCIII dysfunction but showed selective abolition of responsiveness to hypoxia (increased [Ca2+] and transmitter release) with normal responses to other stimuli. Mitochondrial hypoxic NADH and reactive O2 species signals were also suppressed. MCIII-deficient mice exhibited strong inhibition of the hypoxic ventilatory response and altered acclimatization to sustained hypoxia. These data indicate that a functional ETC, with coupling between MCI and MCIV, is required for acute O2 sensing. O2 regulation of breathing results from the integrated action of mitochondrial ETC complexes in arterial chemoreceptors.
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6
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Gao L, Ortega-Sáenz P, Moreno-Domínguez A, López-Barneo J. Mitochondrial Redox Signaling in O 2-Sensing Chemoreceptor Cells. Antioxid Redox Signal 2022; 37:274-289. [PMID: 35044243 DOI: 10.1089/ars.2021.0255] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Significance: Acute responses to hypoxia are essential for the survival of mammals. The carotid body (CB), the main arterial chemoreceptor, contains glomus cells with oxygen (O2)-sensitive K+ channels, which are inhibited during hypoxia to trigger adaptive cardiorespiratory reflexes. Recent Advances: In this review, recent advances in molecular mechanisms of acute O2 sensing in CB glomus cells are discussed, with a special focus on the signaling role of mitochondria through regulating cellular redox status. These advances have been achieved thanks to the use of genetically engineered redox-sensitive green fluorescent protein (roGFP) probes, which allowed us to monitor rapid changes in ROS production in real time in different subcellular compartments during hypoxia. This methodology was used in combination with conditional knockout mice models, pharmacological approaches, and transcriptomic studies. We have proposed a mitochondria-to-membrane signaling model of acute O2 sensing in which H2O2 released in the mitochondrial intermembrane space serves as a signaling molecule to inhibit K+ channels on the plasma membrane. Critical Issues: Changes in mitochondrial reactive oxygen species (ROS) production during acute hypoxia are highly compartmentalized in the submitochondrial regions. The use of redox-sensitive probes targeted to specific compartments is essential to fully understand the role of mitochondrial ROS in acute O2 sensing. Future Directions: Further studies are needed to specify the ROS and to characterize the target(s) of ROS in chemoreceptor cells during acute hypoxia. These data may also contribute to a more complete understanding of the implication of ROS in acute responses to hypoxia in O2-sensing cells in other organs. Antioxid. Redox Signal. 37, 274-289.
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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), 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, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Alejandro Moreno-Domínguez
- 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), Madrid, 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), Madrid, Spain
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7
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Abstract
Oxygen (O2) is essential for life and therefore the supply of sufficient O2 to the tissues is a major physiological challenge. In mammals, a deficit of O2 (hypoxia) triggers rapid cardiorespiratory reflexes (e.g. hyperventilation and increased heart output) that within a few seconds increase the uptake of O2 by the lungs and its distribution throughout the body. The prototypical acute O2-sensing organ is the carotid body (CB), which contains sensory glomus cells expressing O2-regulated ion channels. In response to hypoxia, glomus cells depolarize and release transmitters which activate afferent fibers terminating at the brainstem respiratory and autonomic centers. In this review, we summarize the basic properties of CB chemoreceptor cells and the essential role played by their specialized mitochondria in acute O2 sensing and signaling. We focus on recent data supporting a "mitochondria-to-membrane signaling" model of CB chemosensory transduction. The possibility that the differential expression of specific subunit isoforms and enzymes could allow mitochondria to play a generalized adaptive O2-sensing and signaling role in a wide variety of cells is also discussed.
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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, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,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, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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8
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Knoepp F, Wahl J, Andersson A, Kraut S, Sommer N, Weissmann N, Ramser K. A Microfluidic System for Simultaneous Raman Spectroscopy, Patch-Clamp Electrophysiology, and Live-Cell Imaging to Study Key Cellular Events of Single Living Cells in Response to Acute Hypoxia. SMALL METHODS 2021; 5:e2100470. [PMID: 34927935 DOI: 10.1002/smtd.202100470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/23/2021] [Indexed: 06/14/2023]
Abstract
The ability to sense changes in oxygen availability is fundamentally important for the survival of all aerobic organisms. However, cellular oxygen sensing mechanisms and pathologies remain incompletely understood and studies of acute oxygen sensing, in particular, have produced inconsistent results. Current methods cannot simultaneously measure the key cellular events in acute hypoxia (i.e., changes in redox state, electrophysiological properties, and mechanical responses) at controlled partial pressures of oxygen (pO2 ). The lack of such a comprehensive method essentially contributes to the discrepancies in the field. A sealed microfluidic system that combines i) Raman spectroscopy, ii) patch-clamp electrophysiology, and iii) live-cell imaging under precisely controlled pO2 have therefore been developed. Merging these modalities allows label-free and simultaneous observation of oxygen-dependent alterations in multiple cellular redox couples, membrane potential, and cellular contraction. This technique is adaptable to any cell type and allows in-depth insight into acute oxygen sensing processes underlying various physiologic and pathologic conditions.
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Affiliation(s)
- Fenja Knoepp
- Excellence Cluster Cardio-Pulmonary Institute (CPI), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, D-35392, Giessen, Germany
| | - Joel Wahl
- Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, SE-97187, Sweden
| | - Anders Andersson
- Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, SE-97187, Sweden
| | - Simone Kraut
- Excellence Cluster Cardio-Pulmonary Institute (CPI), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, D-35392, Giessen, Germany
| | - Natascha Sommer
- Excellence Cluster Cardio-Pulmonary Institute (CPI), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, D-35392, Giessen, Germany
| | - Norbert Weissmann
- Excellence Cluster Cardio-Pulmonary Institute (CPI), University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, D-35392, Giessen, Germany
| | - Kerstin Ramser
- Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, SE-97187, Sweden
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9
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Generation of Reactive Oxygen Species by Mitochondria. Antioxidants (Basel) 2021; 10:antiox10030415. [PMID: 33803273 PMCID: PMC8001687 DOI: 10.3390/antiox10030415] [Citation(s) in RCA: 111] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 02/28/2021] [Accepted: 03/01/2021] [Indexed: 12/15/2022] Open
Abstract
Reactive oxygen species (ROS) are series of chemical products originated from one or several electron reductions of oxygen. ROS are involved in physiology and disease and can also be both cause and consequence of many biological scenarios. Mitochondria are the main source of ROS in the cell and, particularly, the enzymes in the electron transport chain are the major contributors to this phenomenon. Here, we comprehensively review the modes by which ROS are produced by mitochondria at a molecular level of detail, discuss recent advances in the field involving signalling and disease, and the involvement of supercomplexes in these mechanisms. Given the importance of mitochondrial ROS, we also provide a schematic guide aimed to help in deciphering the mechanisms involved in their production in a variety of physiological and pathological settings.
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10
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Hecker M, Sommer N, Mayer K. Assessment of Short- and Medium-Chain Fatty Acids on Mitochondrial Function in Severe Inflammation. Methods Mol Biol 2021; 2277:125-132. [PMID: 34080148 DOI: 10.1007/978-1-0716-1270-5_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Mitochondrial dysfunction is regarded as a key factor involved in the pathogenesis of septic disorders, leading to a decline in energy supply. The influence of short- and medium-chain fatty acids (SCFA/MCFA) on mitochondrial respiration under inflammatory conditions has thus far not been investigated. In the following protocol we describe the assessment of mitochondrial respiration using high-resolution respirometry under inflammatory and baseline conditions. For this approach, human endothelial cells and monocytes were pretreated with TNF-α to mimic inflammation followed by incubation with SCFA/MCFA and then subjected to high-resolution respirometry. Mitochondrial DNA content was assessed by PCR .
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Affiliation(s)
- Matthias Hecker
- University of Giessen and Marburg Lung Center (UGMLC), Justus-Liebig- University of Giessen, Giessen, Germany.
| | - Natascha Sommer
- University of Giessen and Marburg Lung Center (UGMLC), Justus-Liebig- University of Giessen, Giessen, Germany
| | - Konstantin Mayer
- University of Giessen and Marburg Lung Center (UGMLC), Justus-Liebig- University of Giessen, Giessen, Germany
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11
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Pak O, Scheibe S, Esfandiary A, Gierhardt M, Sydykov A, Logan A, Fysikopoulos A, Veit F, Hecker M, Kroschel F, Quanz K, Erb A, Schäfer K, Fassbinder M, Alebrahimdehkordi N, Ghofrani HA, Schermuly RT, Brandes RP, Seeger W, Murphy MP, Weissmann N, Sommer N. Impact of the mitochondria-targeted antioxidant MitoQ on hypoxia-induced pulmonary hypertension. Eur Respir J 2018; 51:1701024. [PMID: 29419444 DOI: 10.1183/13993003.01024-2017] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Increased mitochondrial reactive oxygen species (ROS), particularly superoxide have been suggested to mediate hypoxic pulmonary vasoconstriction (HPV), chronic hypoxia-induced pulmonary hypertension (PH) and right ventricular (RV) remodelling.We determined ROS in acute, chronic hypoxia and investigated the effect of the mitochondria-targeted antioxidant MitoQ under these conditions.The effect of MitoQ or its inactive carrier substance, decyltriphenylphosphonium (TPP+), on acute HPV (1% O2 for 10 minutes) was investigated in isolated blood-free perfused mouse lungs. Mice exposed for 4 weeks to chronic hypoxia (10% O2) or after banding of the main pulmonary artery (PAB) were treated with MitoQ or TPP+ (50 mg/kg/day).Total cellular superoxide and mitochondrial ROS levels were increased in pulmonary artery smooth muscle cells (PASMC), but decreased in pulmonary fibroblasts in acute hypoxia. MitoQ significantly inhibited HPV and acute hypoxia-induced rise in superoxide concentration. ROS was decreased in PASMC, while it increased in the RV after chronic hypoxia. Correspondingly, MitoQ did not affect the development of chronic hypoxia-induced PH, but attenuated RV remodelling after chronic hypoxia as well as after PAB.Increased mitochondrial ROS of PASMC mediate acute HPV, but not chronic hypoxia-induced PH. MitoQ may be beneficial under conditions of exaggerated acute HPV.
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Affiliation(s)
- Oleg Pak
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Susan Scheibe
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Azadeh Esfandiary
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Mareike Gierhardt
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Akylbek Sydykov
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Angela Logan
- MRC Mitochondrial Biology Unit, CB2 0XY Cambridge, United Kingdom
| | - Athanasios Fysikopoulos
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Florian Veit
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Matthias Hecker
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Florian Kroschel
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Karin Quanz
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Alexandra Erb
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Katharina Schäfer
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Mirja Fassbinder
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Nasim Alebrahimdehkordi
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Hossein A Ghofrani
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Ralph T Schermuly
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Ralf P Brandes
- Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner site RheinMain, 60590 Frankfurt am Main, Germany
| | - Werner Seeger
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
- Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, CB2 0XY Cambridge, United Kingdom
| | - Norbert Weissmann
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Natascha Sommer
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
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Strielkov I, Pak O, Sommer N, Weissmann N. Recent advances in oxygen sensing and signal transduction in hypoxic pulmonary vasoconstriction. J Appl Physiol (1985) 2017; 123:1647-1656. [PMID: 28751366 DOI: 10.1152/japplphysiol.00103.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hypoxic pulmonary vasoconstriction (HPV) is a physiological reaction, which adapts lung perfusion to regional ventilation and optimizes gas exchange. Impaired HPV may cause systemic hypoxemia, while generalized HPV contributes to the development of pulmonary hypertension. The triggering mechanisms underlying HPV are still not fully elucidated. Several hypotheses are currently under debate, including a possible decrease as well as an increase in reactive oxygen species as a triggering event. Recent findings suggest an increase in the production of reactive oxygen species in pulmonary artery smooth muscle cells by complex III of the mitochondrial electron transport chain and occurrence of oxygen sensing at complex IV. Other essential components are voltage-dependent potassium and possibly L-type, transient receptor potential channel 6, and transient receptor potential vanilloid 4 channels. The release of arachidonic acid metabolites appears also to be involved in HPV regulation. Further investigation of the HPV mechanisms will facilitate the development of novel therapeutic strategies for the treatment of HPV-related disorders.
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Affiliation(s)
- Ievgen Strielkov
- Excellence Cluster Cardiopulmonary System, University of Giessen Lung Center, German Center for Lung Research (DZL), Justus-Liebig-University, Giessen , Germany
| | - Oleg Pak
- Excellence Cluster Cardiopulmonary System, University of Giessen Lung Center, German Center for Lung Research (DZL), Justus-Liebig-University, Giessen , Germany
| | - Natasha Sommer
- Excellence Cluster Cardiopulmonary System, University of Giessen Lung Center, German Center for Lung Research (DZL), Justus-Liebig-University, Giessen , Germany
| | - Norbert Weissmann
- Excellence Cluster Cardiopulmonary System, University of Giessen Lung Center, German Center for Lung Research (DZL), Justus-Liebig-University, Giessen , Germany
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Sommer N, Hüttemann M, Pak O, Scheibe S, Knoepp F, Sinkler C, Malczyk M, Gierhardt M, Esfandiary A, Kraut S, Jonas F, Veith C, Aras S, Sydykov A, Alebrahimdehkordi N, Giehl K, Hecker M, Brandes RP, Seeger W, Grimminger F, Ghofrani HA, Schermuly RT, Grossman LI, Weissmann N. Mitochondrial Complex IV Subunit 4 Isoform 2 Is Essential for Acute Pulmonary Oxygen Sensing. Circ Res 2017; 121:424-438. [PMID: 28620066 DOI: 10.1161/circresaha.116.310482] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 12/14/2016] [Accepted: 06/14/2017] [Indexed: 12/17/2022]
Abstract
RATIONALE Acute pulmonary oxygen sensing is essential to avoid life-threatening hypoxemia via hypoxic pulmonary vasoconstriction (HPV) which matches perfusion to ventilation. Hypoxia-induced mitochondrial superoxide release has been suggested as a critical step in the signaling pathway underlying HPV. However, the identity of the primary oxygen sensor and the mechanism of superoxide release in acute hypoxia, as well as its relevance for chronic pulmonary oxygen sensing, remain unresolved. OBJECTIVES To investigate the role of the pulmonary-specific isoform 2 of subunit 4 of the mitochondrial complex IV (Cox4i2) and the subsequent mediators superoxide and hydrogen peroxide for pulmonary oxygen sensing and signaling. METHODS AND RESULTS Isolated ventilated and perfused lungs from Cox4i2-/- mice lacked acute HPV. In parallel, pulmonary arterial smooth muscle cells (PASMCs) from Cox4i2-/- mice showed no hypoxia-induced increase of intracellular calcium. Hypoxia-induced superoxide release which was detected by electron spin resonance spectroscopy in wild-type PASMCs was absent in Cox4i2-/- PASMCs and was dependent on cysteine residues of Cox4i2. HPV could be inhibited by mitochondrial superoxide inhibitors proving the functional relevance of superoxide release for HPV. Mitochondrial hyperpolarization, which can promote mitochondrial superoxide release, was detected during acute hypoxia in wild-type but not Cox4i2-/- PASMCs. Downstream signaling determined by patch-clamp measurements showed decreased hypoxia-induced cellular membrane depolarization in Cox4i2-/- PASMCs compared with wild-type PASMCs, which could be normalized by the application of hydrogen peroxide. In contrast, chronic hypoxia-induced pulmonary hypertension and pulmonary vascular remodeling were not or only slightly affected by Cox4i2 deficiency, respectively. CONCLUSIONS Cox4i2 is essential for acute but not chronic pulmonary oxygen sensing by triggering mitochondrial hyperpolarization and release of mitochondrial superoxide which, after conversion to hydrogen peroxide, contributes to cellular membrane depolarization and HPV. These findings provide a new model for oxygen-sensing processes in the lung and possibly also in other organs.
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Affiliation(s)
- Natascha Sommer
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Maik Hüttemann
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Oleg Pak
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Susan Scheibe
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Fenja Knoepp
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Christopher Sinkler
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Monika Malczyk
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Mareike Gierhardt
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Azadeh Esfandiary
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Simone Kraut
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Felix Jonas
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Christine Veith
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Siddhesh Aras
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Akylbek Sydykov
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Nasim Alebrahimdehkordi
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Klaudia Giehl
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Matthias Hecker
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Ralf P Brandes
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Werner Seeger
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Friedrich Grimminger
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Hossein A Ghofrani
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Ralph T Schermuly
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
| | - Lawrence I Grossman
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.).
| | - Norbert Weissmann
- From the Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany (N.S., O.P., S.S., F.K., M.M., M.G., A.E., S.K., F.J., C.V., A.S., N.A., K.G., M.H., W.S., F.G., H.A.G., R.T.S., N.W.); Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI (M.H., C.S., S.A., L.I.G.); Institut für Kardiovaskuläre Physiologie, Goethe-Universität, German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Frankfurt am Main, Germany (R.P.B.); and Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany (W.S.)
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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: 27] [Impact Index Per Article: 3.4] [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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15
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Evans AM, Mahmoud AD, Moral-Sanz J, Hartmann S. The emerging role of AMPK in the regulation of breathing and oxygen supply. Biochem J 2016; 473:2561-72. [PMID: 27574022 PMCID: PMC5003690 DOI: 10.1042/bcj20160002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/20/2016] [Accepted: 05/03/2016] [Indexed: 01/25/2023]
Abstract
Regulation of breathing is critical to our capacity to accommodate deficits in oxygen availability and demand during, for example, sleep and ascent to altitude. It is generally accepted that a fall in arterial oxygen increases afferent discharge from the carotid bodies to the brainstem and thus delivers increased ventilatory drive, which restores oxygen supply and protects against hypoventilation and apnoea. However, the precise molecular mechanisms involved remain unclear. We recently identified as critical to this process the AMP-activated protein kinase (AMPK), which is key to the cell-autonomous regulation of metabolic homoeostasis. This observation is significant for many reasons, not least because recent studies suggest that the gene for the AMPK-α1 catalytic subunit has been subjected to natural selection in high-altitude populations. It would appear, therefore, that evolutionary pressures have led to AMPK being utilized to regulate oxygen delivery and thus energy supply to the body in the short, medium and longer term. Contrary to current consensus, however, our findings suggest that AMPK regulates ventilation at the level of the caudal brainstem, even when afferent input responses from the carotid body are normal. We therefore hypothesize that AMPK integrates local hypoxic stress at defined loci within the brainstem respiratory network with an index of peripheral hypoxic status, namely afferent chemosensory inputs. Allied to this, AMPK is critical to the control of hypoxic pulmonary vasoconstriction and thus ventilation-perfusion matching at the lungs and may also determine oxygen supply to the foetus by, for example, modulating utero-placental blood flow.
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Affiliation(s)
- A Mark Evans
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, U.K.
| | - Amira D Mahmoud
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, U.K
| | - Javier Moral-Sanz
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, U.K
| | - Sandy Hartmann
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, U.K
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16
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Pak O, Bakr AG, Gierhardt M, Albus J, Strielkov I, Kroschel F, Hoeres T, Hecker M, Ghofrani HA, Seeger W, Weissmann N, Sommer N. Effects of carbon monoxide-releasing molecules on pulmonary vasoreactivity in isolated perfused lungs. J Appl Physiol (1985) 2016; 120:271-81. [DOI: 10.1152/japplphysiol.00726.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/16/2015] [Indexed: 11/22/2022] Open
Abstract
In addition to its renowned poisonous effects, carbon monoxide (CO) is being recognized for its beneficial actions on inflammatory and vasoregulatory pathways, particularly when applied at low concentrations via CO-releasing molecules (CO-RMs). In the lung, CO gas and CO-RMs are suggested to decrease pulmonary vascular tone and hypoxic pulmonary vasoconstriction (HPV). However, the direct effect of CO-RMs on the pulmonary vasoreactivity in isolated lungs has not yet been investigated. We assessed the effect of CORM-2 and CORM-3 on the pulmonary vasculature during normoxia and acute hypoxia (1% oxygen for 10 min) in isolated ventilated and perfused mouse lungs. The effects were compared with those of inhaled CO gas (10%). The interaction of CORM-2 or CO with cytochrome P-450 (CYP) was measured simultaneously by tissue spectrophotometry. Inhaled CO decreased HPV and vasoconstriction induced by the thromboxane mimetic U-46619 but did not alter KCl-induced vasoconstriction. In contrast, concentrations of CORM-2 and CORM-3 used to elicit beneficial effects on the systemic circulation did not affect pulmonary vascular tone. High concentration of CO-RMs or long-term application induced a continuous increase in normoxic pressure. Inhaled CO showed spectral alterations correlating with the inhibition of CYP. In contrast, during application of CORM-2 spectrophotometric signs of interaction with CYP could not be detected. Application of CO-RMs in therapeutic doses in isolated lungs neither decreases pulmonary vascular tone and HPV nor does it induce spectral alterations that are characteristic of CO-inhibited CYP. High doses, however, may cause pulmonary vasoconstriction.
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Affiliation(s)
- Oleg Pak
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Member of the German Center for Lung Research (DZL), Germany; and
| | - Adel G. Bakr
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Member of the German Center for Lung Research (DZL), Germany; and
- Faculty of Pharmacy, Department of Pharmacology & Toxicology, Al-Azhar University, Assiut, Egypt
| | - Mareike Gierhardt
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Member of the German Center for Lung Research (DZL), Germany; and
| | - Julia Albus
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Member of the German Center for Lung Research (DZL), Germany; and
| | - Ievgen Strielkov
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Member of the German Center for Lung Research (DZL), Germany; and
| | - Florian Kroschel
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Member of the German Center for Lung Research (DZL), Germany; and
| | - Timm Hoeres
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Member of the German Center for Lung Research (DZL), Germany; and
| | - Matthias Hecker
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Member of the German Center for Lung Research (DZL), Germany; and
| | - Hossein A. Ghofrani
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Member of the German Center for Lung Research (DZL), Germany; and
| | - Werner Seeger
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Member of the German Center for Lung Research (DZL), Germany; and
| | - Norbert Weissmann
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Member of the German Center for Lung Research (DZL), Germany; and
| | - Natascha Sommer
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center, Justus-Liebig-University, Giessen, Member of the German Center for Lung Research (DZL), Germany; and
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17
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Sommer N, Strielkov I, Pak O, Weissmann N. Oxygen sensing and signal transduction in hypoxic pulmonary vasoconstriction. Eur Respir J 2015; 47:288-303. [PMID: 26493804 DOI: 10.1183/13993003.00945-2015] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/24/2015] [Indexed: 01/17/2023]
Abstract
Hypoxic pulmonary vasoconstriction (HPV), also known as the von Euler-Liljestrand mechanism, is an essential response of the pulmonary vasculature to acute and sustained alveolar hypoxia. During local alveolar hypoxia, HPV matches perfusion to ventilation to maintain optimal arterial oxygenation. In contrast, during global alveolar hypoxia, HPV leads to pulmonary hypertension. The oxygen sensing and signal transduction machinery is located in the pulmonary arterial smooth muscle cells (PASMCs) of the pre-capillary vessels, albeit the physiological response may be modulated in vivo by the endothelium. While factors such as nitric oxide modulate HPV, reactive oxygen species (ROS) have been suggested to act as essential mediators in HPV. ROS may originate from mitochondria and/or NADPH oxidases but the exact oxygen sensing mechanisms, as well as the question of whether increased or decreased ROS cause HPV, are under debate. ROS may induce intracellular calcium increase and subsequent contraction of PASMCs via direct or indirect interactions with protein kinases, phospholipases, sarcoplasmic calcium channels, transient receptor potential channels, voltage-dependent potassium channels and L-type calcium channels, whose relevance may vary under different experimental conditions. Successful identification of factors regulating HPV may allow development of novel therapeutic approaches for conditions of disturbed HPV.
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Affiliation(s)
- Natascha Sommer
- Excellence Cluster Cardiopulmonary System, University of Giessen Lung Center, German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany
| | - Ievgen Strielkov
- Excellence Cluster Cardiopulmonary System, University of Giessen Lung Center, German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany
| | - Oleg Pak
- Excellence Cluster Cardiopulmonary System, University of Giessen Lung Center, German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany
| | - Norbert Weissmann
- Excellence Cluster Cardiopulmonary System, University of Giessen Lung Center, German Center for Lung Research (DZL), Justus-Liebig-University, Giessen, Germany
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18
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Harrison DK, Fasching M, Fontana-Ayoub M, Gnaiger E. Cytochrome redox states and respiratory control in mouse and beef heart mitochondria at steady-state levels of hypoxia. J Appl Physiol (1985) 2015; 119:1210-8. [PMID: 26251509 DOI: 10.1152/japplphysiol.00146.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 08/03/2015] [Indexed: 11/22/2022] Open
Abstract
Mitochondrial control of cellular redox states is a fundamental component of cell signaling in the coordination of core energy metabolism and homeostasis during normoxia and hypoxia. We investigated the relationship between cytochrome redox states and mitochondrial oxygen consumption at steady-state levels of hypoxia in mitochondria isolated from beef and mouse heart (BHImt, MHImt), comparing two species with different cardiac dynamics and local oxygen demands. A low-noise, rapid spectrophotometric system using visible light for the measurement of cytochrome redox states was combined with high-resolution respirometry. Monophasic hyperbolic relationships were observed between oxygen consumption, JO2, and oxygen partial pressure, Po2, within the range <1.1 kPa (8.3 mmHg; 13 μM). P50j (Po2 at 0.5·Jmax) was 0.015 ± 0.0004 and 0.021 ± 0.003 kPa (0.11 and 0.16 mmHg) for BHImt and MHImt, respectively. Maximum oxygen consumption, Jmax, was measured at saturating ADP levels (OXPHOS capacity) with Complex I-linked substrate supply. Redox states of cytochromes aa3 and c were biphasic hyperbolic functions of Po2. The relationship between cytochrome oxidation state and oxygen consumption revealed a separation of distinct phases from mild to severe and deep hypoxia. When cytochrome c oxidation increased from fully reduced to 45% oxidized at 0.1 Jmax, Po2 was as low as 0.002 kPa (0.02 μM), and trace amounts of oxygen are sufficient to partially oxidize the cytochromes. At higher Po2 under severe hypoxia, respiration increases steeply, whereas redox changes are small. Under mild hypoxia, the steep slope of oxidation of cytochrome c when flux remains more stable represents a cushioning mechanism that helps to maintain respiration high at the onset of hypoxia.
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Affiliation(s)
- David K Harrison
- OROBOROS INSTRUMENTS, Innsbruck, Austria; Microvascular Measurements, St Lorenzen, Italy; and
| | | | | | - Erich Gnaiger
- OROBOROS INSTRUMENTS, Innsbruck, Austria; D Swarowski Research Laboratory, Department of Visceral Transplant and Thoracic Surgery, Medical University of Innsbruck, Austria
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19
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Evans AM, Lewis SA, Ogunbayo OA, Moral-Sanz J. Modulation of the LKB1-AMPK Signalling Pathway Underpins Hypoxic Pulmonary Vasoconstriction and Pulmonary Hypertension. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 860:89-99. [PMID: 26303471 DOI: 10.1007/978-3-319-18440-1_11] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Perhaps the defining characteristic of pulmonary arteries is the process of hypoxic pulmonary vasoconstriction (HPV) which, under physiological conditions, supports ventilation-perfusion matching in the lung by diverting blood flow away from oxygen deprived areas of the lung to oxygen rich regions. However, when alveolar hypoxia is more widespread, either at altitude or with disease (e.g., cystic fibrosis), HPV may lead to hypoxic pulmonary hypertension. HPV is driven by the intrinsic response to hypoxia of pulmonary arterial smooth muscle and endothelial cells, which are acutely sensitive to relatively small changes in pO2 and have evolved to monitor oxygen supply and thus address ventilation-perfusion mismatch. There is now a consensus that the inhibition by hypoxia of mitochondrial oxidative phosphorylation represents a key step towards the induction of HPV, but the precise nature of the signalling pathway(s) engaged thereafter remains open to debate. We will consider the role of the AMP-activated protein kinase (AMPK) and liver kinase B1 (LKB1), an upstream kinase through which AMPK is intimately coupled to changes in oxygen supply via mitochondrial metabolism. A growing body of evidence, from our laboratory and others, suggests that modulation of the LKB1-AMPK signalling pathway underpins both hypoxic pulmonary vasoconstriction and the development of pulmonary hypertension.
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Affiliation(s)
- A Mark Evans
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh, EH8 9XD, UK,
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20
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Hecker M, Sommer N, Mayer K. Assessment of short- and medium-chain fatty acids on mitochondrial function in severe inflammation. Methods Mol Biol 2015; 1265:389-396. [PMID: 25634290 DOI: 10.1007/978-1-4939-2288-8_28] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Mitochondrial dysfunction is regarded as one key factor involved in the pathogenesis of septic disorders, leading to a decline in energy supply. The influence of short- and medium-chain fatty acids (SCFA/MCFA) on mitochondrial respiration under inflammatory conditions has thus far not been investigated. In the following protocol, we describe the assessment of mitochondrial respiration using high-resolution respirometry under inflammatory and baseline conditions. For this approach, human endothelial cells and monocytes were pretreated with TNF-α to mimic inflammation followed by incubation with SCFA/MCFA and then subjected to high-resolution respirometry. Mitochondrial DNA content was assessed by PCR.
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Affiliation(s)
- Matthias Hecker
- University of Giessen and Marburg Lung Center (UGMLC), Justus-Liebig-University of Giessen, Giessen, Germany,
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21
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Soltysinska E, Bentzen BH, Barthmes M, Hattel H, Thrush AB, Harper ME, Qvortrup K, Larsen FJ, Schiffer TA, Losa-Reyna J, Straubinger J, Kniess A, Thomsen MB, Brüggemann A, Fenske S, Biel M, Ruth P, Wahl-Schott C, Boushel RC, Olesen SP, Lukowski R. KCNMA1 encoded cardiac BK channels afford protection against ischemia-reperfusion injury. PLoS One 2014; 9:e103402. [PMID: 25072914 PMCID: PMC4114839 DOI: 10.1371/journal.pone.0103402] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 07/01/2014] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial potassium channels have been implicated in myocardial protection mediated through pre-/postconditioning. Compounds that open the Ca2+- and voltage-activated potassium channel of big-conductance (BK) have a pre-conditioning-like effect on survival of cardiomyocytes after ischemia/reperfusion injury. Recently, mitochondrial BK channels (mitoBKs) in cardiomyocytes were implicated as infarct-limiting factors that derive directly from the KCNMA1 gene encoding for canonical BKs usually present at the plasma membrane of cells. However, some studies challenged these cardio-protective roles of mitoBKs. Herein, we present electrophysiological evidence for paxilline- and NS11021-sensitive BK-mediated currents of 190 pS conductance in mitoplasts from wild-type but not BK-/- cardiomyocytes. Transmission electron microscopy of BK-/- ventricular muscles fibres showed normal ultra-structures and matrix dimension, but oxidative phosphorylation capacities at normoxia and upon re-oxygenation after anoxia were significantly attenuated in BK-/- permeabilized cardiomyocytes. In the absence of BK, post-anoxic reactive oxygen species (ROS) production from cardiomyocyte mitochondria was elevated indicating that mitoBK fine-tune the oxidative state at hypoxia and re-oxygenation. Because ROS and the capacity of the myocardium for oxidative metabolism are important determinants of cellular survival, we tested BK-/- hearts for their response in an ex-vivo model of ischemia/reperfusion (I/R) injury. Infarct areas, coronary flow and heart rates were not different between wild-type and BK-/- hearts upon I/R injury in the absence of ischemic pre-conditioning (IP), but differed upon IP. While the area of infarction comprised 28±3% of the area at risk in wild-type, it was increased to 58±5% in BK-/- hearts suggesting that BK mediates the beneficial effects of IP. These findings suggest that cardiac BK channels are important for proper oxidative energy supply of cardiomyocytes at normoxia and upon re-oxygenation after prolonged anoxia and that IP might indeed favor survival of the myocardium upon I/R injury in a BK-dependent mode stemming from both mitochondrial post-anoxic ROS modulation and non-mitochondrial localizations.
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MESH Headings
- Animals
- Cell Hypoxia
- Disease Models, Animal
- Energy Metabolism
- Indoles/pharmacology
- Ischemic Preconditioning
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/genetics
- Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/metabolism
- Large-Conductance Calcium-Activated Potassium Channels/chemistry
- Large-Conductance Calcium-Activated Potassium Channels/genetics
- Large-Conductance Calcium-Activated Potassium Channels/metabolism
- Membrane Potential, Mitochondrial/drug effects
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mitochondria, Heart/metabolism
- Muscle Fibers, Skeletal/ultrastructure
- Muscle, Skeletal/metabolism
- Myocardium/metabolism
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Oxidative Phosphorylation/drug effects
- Reactive Oxygen Species/metabolism
- Reperfusion Injury/metabolism
- Reperfusion Injury/pathology
- Tetrazoles/pharmacology
- Thiourea/analogs & derivatives
- Thiourea/pharmacology
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Affiliation(s)
- Ewa Soltysinska
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bo Hjorth Bentzen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
| | - Maria Barthmes
- Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität, Munich, Germany
- Nanion Technologies GmbH, Munich, Germany
| | - Helle Hattel
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - A. Brianne Thrush
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Mary-Ellen Harper
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Klaus Qvortrup
- Department of Biomedical Sciences, Core Facility for Integrated Microscopy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip J. Larsen
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Tomas A. Schiffer
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Jose Losa-Reyna
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Julia Straubinger
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Angelina Kniess
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Morten Bækgaard Thomsen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Stefanie Fenske
- Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität, Munich, Germany
| | - Martin Biel
- Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität, Munich, Germany
| | - Peter Ruth
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Christian Wahl-Schott
- Center for Integrated Protein Science Munich (CIPSM), Ludwig-Maximilians-Universität, Munich, Germany; Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität, Munich, Germany
| | - Robert Christopher Boushel
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Søren-Peter Olesen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (SPO); (RL)
| | - Robert Lukowski
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
- * E-mail: (SPO); (RL)
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22
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Brand MD, Orr AL, Perevoshchikova IV, Quinlan CL. The role of mitochondrial function and cellular bioenergetics in ageing and disease. Br J Dermatol 2014; 169 Suppl 2:1-8. [PMID: 23786614 DOI: 10.1111/bjd.12208] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mitochondria constitute an important topic of biomedical enquiry (one paper in every 154 indexed in PubMed since 1998 is retrieved by the keyword 'mitochondria') because of widespread recognition of their importance in cell physiology and pathology. Mitochondrial dysfunction is widely implicated in ageing and in the diseases of ageing, through dysfunction in adenosine triphosphate (ATP) synthesis, Ca(2+) homeostasis, central metabolic pathways or radical production. Nonetheless, the mechanisms and regulation of superoxide and hydrogen peroxide formation by mitochondria remain poorly described. Measurement of the capacities of different sites of superoxide and hydrogen peroxide production in isolated skeletal muscle mitochondria show that the maximum capacities of sites in complexes I, II and III and in several associated redox enzymes greatly exceed the native rates observed in the absence of respiratory chain inhibitors. In vitro, the native rates and the relative importance of different sites both depend on the substrate being oxidized, with sites IQ, IIF, GPDH, IF and IIIQo each being important with particular substrates. The techniques involved in measuring rates from each site should become applicable to cell cultures and in vivo in the future.
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Affiliation(s)
- M D Brand
- The Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, USA.
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23
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Perevoshchikova IV, Quinlan CL, Orr AL, Gerencser AA, Brand MD. Sites of superoxide and hydrogen peroxide production during fatty acid oxidation in rat skeletal muscle mitochondria. Free Radic Biol Med 2013; 61:298-309. [PMID: 23583329 PMCID: PMC3871980 DOI: 10.1016/j.freeradbiomed.2013.04.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Revised: 02/01/2013] [Accepted: 04/05/2013] [Indexed: 12/22/2022]
Abstract
H2O2 production by skeletal muscle mitochondria oxidizing palmitoylcarnitine was examined under two conditions: the absence of respiratory chain inhibitors and the presence of myxothiazol to inhibit complex III. Without inhibitors, respiration and H2O2 production were low unless carnitine or malate was added to limit acetyl-CoA accumulation. With palmitoylcarnitine alone, H2O2 production was dominated by complex II (44% from site IIF in the forward reaction); the remainder was mostly from complex I (34%, superoxide from site IF). With added carnitine, H2O2 production was about equally shared between complexes I, II, and III. With added malate, it was 75% from complex III (superoxide from site IIIQo) and 25% from site IF. Thus complex II (site IIF in the forward reaction) is a major source of H2O2 production during oxidation of palmitoylcarnitine ± carnitine. Under the second condition (myxothiazol present to keep ubiquinone reduced), the rates of H2O2 production were highest in the presence of palmitoylcarnitine ± carnitine and were dominated by complex II (site IIF in the reverse reaction). About half the rest was from site IF, but a significant portion, ∼40pmol H2O2·min(-1)·mg protein(-1), was not from complex I, II, or III and was attributed to the proteins of β-oxidation (electron-transferring flavoprotein (ETF) and ETF-ubiquinone oxidoreductase). The maximum rate from the ETF system was ∼200pmol H2O2·min(-1)·mg protein(-1) under conditions of compromised antioxidant defense and reduced ubiquinone pool. Thus complex II and the ETF system both contribute to H2O2 productionduring fatty acid oxidation under appropriate conditions.
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Affiliation(s)
| | | | - Adam L Orr
- Buck Institute for Research on Aging, Novato, CA 94945, USA
| | | | - Martin D Brand
- Buck Institute for Research on Aging, Novato, CA 94945, USA
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24
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Hecker M, Sommer N, Voigtmann H, Pak O, Mohr A, Wolf M, Vadász I, Herold S, Weissmann N, Morty RE, Seeger W, Mayer K. Impact of short- and medium-chain fatty acids on mitochondrial function in severe inflammation. JPEN J Parenter Enteral Nutr 2013; 38:587-94. [PMID: 23703093 DOI: 10.1177/0148607113489833] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/15/2013] [Indexed: 12/11/2022]
Abstract
BACKGROUND Sepsis is a severe inflammatory disorder with a high mortality in intensive care units mostly due to multiorgan failure. Mitochondrial dysfunction is regarded as a key factor involved in the pathogenesis of septic disorders, leading to a decline in energy supply. The aim of the present study was to evaluate whether application of short-chain fatty acids (SCFAs) and medium-chain fatty acids (MCFAs) could improve mitochondrial function and thus might serve as a potential energy source under inflammatory conditions. MATERIALS AND METHODS As an experimental approach, starved human endothelial cells and monocytes were incubated with hexanoic acid, heptanoic acid, octanoic acid, or glucose and subsequently subjected to high-resolution respirometry to assess mitochondrial function under baseline conditions. In a second set of experiments, cells were pretreated with tumor necrosis factor-α to mimic inflammation and sepsis. RESULTS We demonstrated that addition of SCFAs and MCFAs increases mitochondrial respiratory capacity at baseline and inflammatory conditions in both cell types. None of the fatty acids induced changes in mitochondrial DNA content or the generation of proinflammatory cytokines, indicating a beneficial safety profile. CONCLUSION We deduce that SCFAs and MCFAs are suitable and safe sources of energy under inflammatory conditions with the capability to partly restore mitochondrial respiration.
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Affiliation(s)
- Matthias Hecker
- University of Giessen Lung Center (UGLC), Justus-Liebig-University of Giessen, Giessen, Germany
| | - Natascha Sommer
- University of Giessen Lung Center (UGLC), Justus-Liebig-University of Giessen, Giessen, Germany
| | - Hans Voigtmann
- University of Giessen Lung Center (UGLC), Justus-Liebig-University of Giessen, Giessen, Germany
| | - Oleg Pak
- University of Giessen Lung Center (UGLC), Justus-Liebig-University of Giessen, Giessen, Germany
| | - Andrea Mohr
- University of Giessen Lung Center (UGLC), Justus-Liebig-University of Giessen, Giessen, Germany
| | | | - István Vadász
- University of Giessen Lung Center (UGLC), Justus-Liebig-University of Giessen, Giessen, Germany
| | - Susanne Herold
- University of Giessen Lung Center (UGLC), Justus-Liebig-University of Giessen, Giessen, Germany
| | - Norbert Weissmann
- University of Giessen Lung Center (UGLC), Justus-Liebig-University of Giessen, Giessen, Germany
| | - Rory E Morty
- Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Werner Seeger
- University of Giessen Lung Center (UGLC), Justus-Liebig-University of Giessen, Giessen, Germany
| | - Konstantin Mayer
- University of Giessen Lung Center (UGLC), Justus-Liebig-University of Giessen, Giessen, Germany
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Bleier L, Dröse S. Superoxide generation by complex III: from mechanistic rationales to functional consequences. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:1320-31. [PMID: 23269318 DOI: 10.1016/j.bbabio.2012.12.002] [Citation(s) in RCA: 231] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 12/05/2012] [Accepted: 12/12/2012] [Indexed: 01/21/2023]
Abstract
Apart from complex I (NADH:ubiquinone oxidoreductase) the mitochondrial cytochrome bc1 complex (complex III; ubiquinol:cytochrome c oxidoreductase) has been identified as the main producer of superoxide and derived reactive oxygen species (ROS) within the mitochondrial respiratory chain. Mitochondrial ROS are generally linked to oxidative stress, aging and other pathophysiological settings like in neurodegenerative diseases. However, ROS produced at the ubiquinol oxidation center (center P, Qo site) of complex III seem to have additional physiological functions as signaling molecules during cellular processes like the adaptation to hypoxia. The molecular mechanism of superoxide production that is mechanistically linked to the electron bifurcation during ubiquinol oxidation is still a matter of debate. Some insight comes from extensive kinetic studies with mutated complexes from yeast and bacterial cytochrome bc1 complexes. This review is intended to bridge the gap between those mechanistic studies and investigations on complex III ROS in cellular signal transduction and highlights factors that impact superoxide generation. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
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Affiliation(s)
- Lea Bleier
- Molecular Bioenergetics Group, Medical School, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany
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Abstract
It has been known for more than 60 years, and suspected for over 100, that alveolar hypoxia causes pulmonary vasoconstriction by means of mechanisms local to the lung. For the last 20 years, it has been clear that the essential sensor, transduction, and effector mechanisms responsible for hypoxic pulmonary vasoconstriction (HPV) reside in the pulmonary arterial smooth muscle cell. The main focus of this review is the cellular and molecular work performed to clarify these intrinsic mechanisms and to determine how they are facilitated and inhibited by the extrinsic influences of other cells. Because the interaction of intrinsic and extrinsic mechanisms is likely to shape expression of HPV in vivo, we relate results obtained in cells to HPV in more intact preparations, such as intact and isolated lungs and isolated pulmonary vessels. Finally, we evaluate evidence regarding the contribution of HPV to the physiological and pathophysiological processes involved in the transition from fetal to neonatal life, pulmonary gas exchange, high-altitude pulmonary edema, and pulmonary hypertension. Although understanding of HPV has advanced significantly, major areas of ignorance and uncertainty await resolution.
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Affiliation(s)
- J. T. Sylvester
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Larissa A. Shimoda
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Philip I. Aaronson
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Jeremy P. T. Ward
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
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Abstract
PURPOSE OF REVIEW Hypoxic pulmonary vasoconstriction (HPV) is driven by the intrinsic response to hypoxia of pulmonary arterial smooth muscle and endothelial cells. These are representatives of a group of specialized O2-sensing cells, defined by their acute sensitivity to relatively small changes in pO2, which have evolved to modulate respiratory and circulatory function in order to maintain O2 supply within physiological limits. The aim of this article is to discuss recent investigations into the mechanism(s) of hypoxia-response coupling and, in light of these, provide a critical assessment of current working hypotheses. RECENT FINDINGS Upon exposure to hypoxia state-of-the-art technologies have now confirmed that mitochondrial oxidative phosphorylation is inhibited in all O2-sensing cells, including pulmonary arterial smooth muscle cells. Thereafter, evidence has been presented to indicate a role as principal effector for the 'gasotransmitters' carbon monoxide and hydrogen sulphide, reactive oxygen species or, in marked contrast, reduced cellular redox couples. Considering recent evidence in favour and against these proposals we suggest that an alternative mechanism may be key, namely the activation of adenosine monophosphate-activated protein kinase consequent to inhibition of mitochondrial oxidative phosphorylation. SUMMARY HPV supports ventilation-perfusion matching in the lung by diverting blood flow away from oxygen-deprived areas towards regions rich in O2. However, in diseases such as emphysema and cystic fibrosis, widespread HPV leads to hypoxic pulmonary hypertension and ultimately right heart failure. Determining the precise mechanism(s) that underpins hypoxia-response coupling will therefore advance understanding of the fundamental processes contributing to related pathophysiology and provide for improved therapeutics.
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Korde AS, Yadav VR, Zheng YM, Wang YX. Primary role of mitochondrial Rieske iron-sulfur protein in hypoxic ROS production in pulmonary artery myocytes. Free Radic Biol Med 2011; 50:945-52. [PMID: 21238580 PMCID: PMC3051030 DOI: 10.1016/j.freeradbiomed.2011.01.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 01/04/2011] [Accepted: 01/06/2011] [Indexed: 12/20/2022]
Abstract
This study was designed to determine whether: (1) hypoxia could directly affect ROS production in isolated mitochondria and mitochondrial complex III from pulmonary artery smooth muscle cells (PASMCs) and (2) Rieske iron-sulfur protein in complex III might mediate hypoxic ROS production, leading to hypoxic pulmonary vasoconstriction (HPV). Our data, for the first time, demonstrate that hypoxia significantly enhances ROS production, measured by the standard ROS indicator dichlorodihydrofluorescein/diacetate, in isolated mitochondria from PASMCs. Studies using the newly developed, specific ROS biosensor pHyPer have found that hypoxia increases mitochondrial ROS generation in isolated PASMCs as well. Hypoxic ROS production has also been observed in isolated complex III. Rieske iron-sulfur protein silencing using siRNA abolishes the hypoxic ROS formation in isolated PASM complex III, mitochondria, and cells, whereas Rieske iron-sulfur protein overexpression produces the opposite effect. Rieske iron-sulfur protein silencing inhibits the hypoxic increase in [Ca(2+)](i) in PASMCs and hypoxic vasoconstriction in isolated PAs. These findings together provide novel evidence that mitochondria are the direct hypoxic targets in PASMCs, in which Rieske iron-sulfur protein in complex III may serve as an essential, primary molecule that mediates the hypoxic ROS generation, leading to an increase in intracellular Ca(2+) in PASMCs and HPV.
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Affiliation(s)
| | | | | | - Yong-Xiao Wang
- Corresponding author: Dr. Yong-Xiao Wang Albany Medical College Center for Cardiovascular Sciences (MC-8) 47 New Scotland Avenue Albany, NY 12208 Phone: (518)-262-9506 Fax: (518)-262-8101
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Bibliography. Current world literature. Thoracic anesthesia. Curr Opin Anaesthesiol 2011; 24:111-3. [PMID: 21321525 DOI: 10.1097/aco.0b013e3283433a20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Hebbel RP. Reconstructing sickle cell disease: a data-based analysis of the "hyperhemolysis paradigm" for pulmonary hypertension from the perspective of evidence-based medicine. Am J Hematol 2011; 86:123-54. [PMID: 21264896 DOI: 10.1002/ajh.21952] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The "hyperhemolytic paradigm" (HHP) posits that hemolysis in sickle disease sequentially and causally establishes increased cell-free plasma Hb, consumption of NO, a state of NO biodeficiency, endothelial dysfunction, and a high prevalence of pulmonary hypertension. The basic science underpinning this concept has added an important facet to the complexity of vascular pathobiology in sickle disease, and clinical research has identified worrisome clinical issues. However, this critique identifies and explains a number of significant concerns about the various HHP component tenets. In addressing these issues, this report presents: a very brief history of the HHP, an integrated synthesis of mechanisms underlying sickle hemolysis, a review of the evidentiary value of hemolysis biomarkers, an examination of evidence bearing on existence of a hyperhemolytic subgroup, and a series of questions that should naturally be applied to the HHP if it is examined using critical thinking skills, the fundamental basis of evidence-based medicine. The veracity of different HHP tenets is found to vary from true, to weakly supported, to demonstrably false. The thesis is developed that the HHP has misidentified the mechanism and clinical significance of its findings. The extant research questions identified by these analyses are delineated, and a conservative, evidence-based approach is suggested for application in clinical medicine.
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Affiliation(s)
- Robert P. Hebbel
- Department of Medicine, Division of Hematology‐Oncology‐Transplantation, Vascular Biology Center, University of Minnesota Medical School, Minneapolis, Minnesota
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