1
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Gessner G, Jamili M, Tomczyk P, Menche D, Schönherr R, Hoshi T, Heinemann SH. Extracellular hemin is a reverse use-dependent gating modifier of cardiac voltage-gated Na + channels. Biol Chem 2022; 403:1067-1081. [PMID: 36038266 DOI: 10.1515/hsz-2022-0194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 08/10/2022] [Indexed: 02/07/2023]
Abstract
Heme (Fe2+-protoporphyrin IX) is a well-known protein prosthetic group; however, heme and hemin (Fe3+-protoporphyrin IX) are also increasingly viewed as signaling molecules. Among the signaling targets are numerous ion channels, with intracellular-facing heme-binding sites modulated by heme and hemin in the sub-µM range. Much less is known about extracellular hemin, which is expected to be more abundant, in particular after hemolytic insults. Here we show that the human cardiac voltage-gated sodium channel hNaV1.5 is potently inhibited by extracellular hemin (IC 50 ≈ 80 nM), while heme, dimethylhemin, and protoporphyrin IX are ineffective. Hemin is selective for hNaV1.5 channels: hNaV1.2, hNaV1.4, hNaV1.7, and hNaV1.8 are insensitive to 1 µM hemin. Using domain chimeras of hNaV1.5 and rat rNaV1.2, domain II was identified as the critical determinant. Mutation N803G in the domain II S3/S4 linker largely diminished the impact of hemin on the cardiac channel. This profile is reminiscent of the interaction of some peptide voltage-sensor toxins with NaV channels. In line with a mechanism of select gating modifiers, the impact of hemin on NaV1.5 channels is reversely use dependent, compatible with an interaction of hemin and the voltage sensor of domain II. Extracellular hemin thus has potential to modulate the cardiac function.
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Affiliation(s)
- Guido Gessner
- Department of Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena and Jena University Hospital, Hans-Knöll-Straße 2, D-07745 Jena, Germany
| | - Mahdi Jamili
- Department of Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena and Jena University Hospital, Hans-Knöll-Straße 2, D-07745 Jena, Germany
| | - Pascal Tomczyk
- Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany
| | - Dirk Menche
- Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, D-53121 Bonn, Germany
| | - Roland Schönherr
- Department of Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena and Jena University Hospital, Hans-Knöll-Straße 2, D-07745 Jena, Germany
| | - Toshinori Hoshi
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104-6085, USA
| | - Stefan H Heinemann
- Department of Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University Jena and Jena University Hospital, Hans-Knöll-Straße 2, D-07745 Jena, Germany
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2
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Intracellular hemin is a potent inhibitor of the voltage-gated potassium channel Kv10.1. Sci Rep 2022; 12:14645. [PMID: 36030326 PMCID: PMC9420133 DOI: 10.1038/s41598-022-18975-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/23/2022] [Indexed: 11/08/2022] Open
Abstract
Heme, an iron-protoporphyrin IX complex, is a cofactor bound to various hemoproteins and supports a broad range of functions, such as electron transfer, oxygen transport, signal transduction, and drug metabolism. In recent years, there has been a growing recognition of heme as a non-genomic modulator of ion channel functions. Here, we show that intracellular free heme and hemin modulate human ether à go-go (hEAG1, Kv10.1) voltage-gated potassium channels. Application of hemin to the intracellular side potently inhibits Kv10.1 channels with an IC50 of about 4 nM under ambient and 63 nM under reducing conditions in a weakly voltage-dependent manner, favoring inhibition at resting potential. Functional studies on channel mutants and biochemical analysis of synthetic and recombinant channel fragments identified a heme-binding motif CxHx8H in the C-linker region of the Kv10.1 C terminus, with cysteine 541 and histidines 543 and 552 being important for hemin binding. Binding of hemin to the C linker may induce a conformational constraint that interferes with channel gating. Our results demonstrate that heme and hemin are endogenous modulators of Kv10.1 channels and could be exploited to modulate Kv10.1-mediated cellular functions.
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3
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Bae H, Kim T, Lim I. Carbon monoxide activation of delayed rectifier potassium currents of human cardiac fibroblasts through diverse pathways. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2022; 26:25-36. [PMID: 34965993 PMCID: PMC8723981 DOI: 10.4196/kjpp.2022.26.1.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/28/2021] [Accepted: 09/28/2021] [Indexed: 06/14/2023]
Abstract
To identify the effect and mechanism of carbon monoxide (CO) on delayed rectifier K+ currents (IK) of human cardiac fibroblasts (HCFs), we used the wholecell mode patch-clamp technique. Application of CO delivered by carbon monoxidereleasing molecule-3 (CORM3) increased the amplitude of outward K+ currents, and diphenyl phosphine oxide-1 (a specific IK blocker) inhibited the currents. CORM3- induced augmentation was blocked by pretreatment with nitric oxide synthase blockers (L-NG-monomethyl arginine citrate and L-NG-nitro arginine methyl ester). Pretreatment with KT5823 (a protein kinas G blocker), 1H-[1,-2,-4] oxadiazolo-[4,-3-a] quinoxalin-1-on (ODQ, a soluble guanylate cyclase blocker), KT5720 (a protein kinase A blocker), and SQ22536 (an adenylate cyclase blocker) blocked the CORM3 stimulating effect on IK. In addition, pretreatment with SB239063 (a p38 mitogen-activated protein kinase [MAPK] blocker) and PD98059 (a p44/42 MAPK blocker) also blocked the CORM3's effect on the currents. When testing the involvement of S-nitrosylation, pretreatment of N-ethylmaleimide (a thiol-alkylating reagent) blocked CO-induced IK activation and DL-dithiothreitol (a reducing agent) reversed this effect. Pretreatment with 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)-21H,23H porphyrin manganese (III) pentachloride and manganese (III) tetrakis (4-benzoic acid) porphyrin chloride (superoxide dismutase mimetics), diphenyleneiodonium chloride (an NADPH oxidase blocker), or allopurinol (a xanthine oxidase blocker) also inhibited CO-induced IK activation. These results suggest that CO enhances IK in HCFs through the nitric oxide, phosphorylation by protein kinase G, protein kinase A, and MAPK, S-nitrosylation and reduction/oxidation (redox) signaling pathways.
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Affiliation(s)
- Hyemi Bae
- Department of Physiology, College of Medicine, Chung-Ang University, Seoul 06974, Korea
| | - Taeho Kim
- Department of Internal Medicine, College of Medicine, Chung-Ang University Hospital, Seoul 06973, Korea
| | - Inja Lim
- Department of Physiology, College of Medicine, Chung-Ang University, Seoul 06974, Korea
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4
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Gallio A, Fung SSP, Cammack-Najera A, Hudson AJ, Raven EL. Understanding the Logistics for the Distribution of Heme in Cells. JACS AU 2021; 1:1541-1555. [PMID: 34723258 PMCID: PMC8549057 DOI: 10.1021/jacsau.1c00288] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Indexed: 05/03/2023]
Abstract
Heme is essential for the survival of virtually all living systems-from bacteria, fungi, and yeast, through plants to animals. No eukaryote has been identified that can survive without heme. There are thousands of different proteins that require heme in order to function properly, and these are responsible for processes such as oxygen transport, electron transfer, oxidative stress response, respiration, and catalysis. Further to this, in the past few years, heme has been shown to have an important regulatory role in cells, in processes such as transcription, regulation of the circadian clock, and the gating of ion channels. To act in a regulatory capacity, heme needs to move from its place of synthesis (in mitochondria) to other locations in cells. But while there is detailed information on how the heme lifecycle begins (heme synthesis), and how it ends (heme degradation), what happens in between is largely a mystery. Here we summarize recent information on the quantification of heme in cells, and we present a discussion of a mechanistic framework that could meet the logistical challenge of heme distribution.
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Affiliation(s)
- Andrea
E. Gallio
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
| | - Simon S.-P. Fung
- Department
of Chemistry and Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, U.K.
| | - Ana Cammack-Najera
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
| | - Andrew J. Hudson
- Department
of Chemistry and Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, U.K.
| | - Emma L. Raven
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
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5
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Yoo HY, Kim SJ. Oxygen-dependent regulation of ion channels: acute responses, post-translational modification, and response to chronic hypoxia. Pflugers Arch 2021; 473:1589-1602. [PMID: 34142209 DOI: 10.1007/s00424-021-02590-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/15/2021] [Accepted: 05/30/2021] [Indexed: 12/19/2022]
Abstract
Oxygen is a vital element for the survival of cells in multicellular aerobic organisms such as mammals. Lack of O2 availability caused by environmental or pathological conditions leads to hypoxia. Active oxygen distribution systems (pulmonary and circulatory) and their neural control mechanisms ensure that cells and tissues remain oxygenated. However, O2-carrying blood cells as well as immune and various parenchymal cells experience wide variations in partial pressure of oxygen (PO2) in vivo. Hence, the reactive modulation of the functions of the oxygen distribution systems and their ability to sense PO2 are critical. Elucidating the physiological responses of cells to variations in PO2 and determining the PO2-sensing mechanisms at the biomolecular level have attracted considerable research interest in the field of physiology. Herein, we review the current knowledge regarding ion channel-dependent oxygen sensing and associated signalling pathways in mammals. First, we present the recent findings on O2-sensing ion channels in representative chemoreceptor cells as well as in other types of cells such as immune cells. Furthermore, we highlight the transcriptional regulation of ion channels under chronic hypoxia and its physiological implications and summarize the findings of studies on the post-translational modification of ion channels under hypoxic or ischemic conditions.
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Affiliation(s)
- Hae Young Yoo
- Department of Nursing, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea. .,Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea.
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6
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Rodrat M, Jantarajit W, Ng DRS, Harvey BSJ, Liu J, Wilkinson WJ, Charoenphandhu N, Sheppard DN. Carbon monoxide-releasing molecules inhibit the cystic fibrosis transmembrane conductance regulator Cl - channel. Am J Physiol Lung Cell Mol Physiol 2020; 319:L997-L1009. [PMID: 32936026 DOI: 10.1152/ajplung.00440.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The gasotransmitter carbon monoxide (CO) regulates fluid and electrolyte movements across epithelial tissues. However, its action on anion channels is incompletely understood. Here, we investigate the direct action of CO on the cystic fibrosis transmembrane conductance regulator (CFTR) by applying CO-releasing molecules (CO-RMs) to the intracellular side of excised inside-out membrane patches from cells heterologously expressing wild-type human CFTR. Addition of increasing concentrations of tricarbonyldichlororuthenium(II) dimer (CORM-2) (1-300 μM) inhibited CFTR channel activity, whereas the control RuCl3 (100 μM) was without effect. CORM-2 predominantly inhibited CFTR by decreasing the frequency of channel openings and, hence, open probability (Po). But, it also reduced current flow through open channels with very fast kinetics, particularly at elevated concentrations. By contrast, the chemically distinct CO-releasing molecule CORM-3 inhibited CFTR by decreasing Po without altering current flow through open channels. Neither depolarizing the membrane voltage nor raising the ATP concentration on the intracellular side of the membrane affected CFTR inhibition by CORM-2. Interestingly, CFTR inhibition by CORM-2, but not by CFTRinh-172, was prevented by prior enhancement of channel activity by the clinically approved CFTR potentiator ivacaftor. Similarly, when added after CORM-2, ivacaftor completely relieved CFTR inhibition. In conclusion, CORM-2 has complex effects on wild-type human CFTR consistent with allosteric inhibition and open-channel blockade. Inhibition of CFTR by CO-releasing molecules suggests that CO regulates CFTR activity and that the gasotransmitter has tissue-specific effects on epithelial ion transport. The action of ivacaftor on CFTR Cl- channels inhibited by CO potentially expands the drug's clinical utility.
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Affiliation(s)
- Mayuree Rodrat
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Walailak Jantarajit
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Demi R S Ng
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Bartholomew S J Harvey
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Jia Liu
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | | | - Narattaphol Charoenphandhu
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand.,Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand.,The Academy of Science, The Royal Society of Thailand, Dusit, Bangkok, Thailand
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
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7
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Burton MJ, Cresser-Brown J, Thomas M, Portolano N, Basran J, Freeman SL, Kwon H, Bottrill AR, Llansola-Portoles MJ, Pascal AA, Jukes-Jones R, Chernova T, Schmid R, Davies NW, Storey NM, Dorlet P, Moody PCE, Mitcheson JS, Raven EL. Discovery of a heme-binding domain in a neuronal voltage-gated potassium channel. J Biol Chem 2020; 295:13277-13286. [PMID: 32723862 DOI: 10.1074/jbc.ra120.014150] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/24/2020] [Indexed: 12/12/2022] Open
Abstract
The EAG (ether-à-go-go) family of voltage-gated K+ channels are important regulators of neuronal and cardiac action potential firing (excitability) and have major roles in human diseases such as epilepsy, schizophrenia, cancer, and sudden cardiac death. A defining feature of EAG (Kv10-12) channels is a highly conserved domain on the N terminus, known as the eag domain, consisting of a Per-ARNT-Sim (PAS) domain capped by a short sequence containing an amphipathic helix (Cap domain). The PAS and Cap domains are both vital for the normal function of EAG channels. Using heme-affinity pulldown assays and proteomics of lysates from primary cortical neurons, we identified that an EAG channel, hERG3 (Kv11.3), binds to heme. In whole-cell electrophysiology experiments, we identified that heme inhibits hERG3 channel activity. In addition, we expressed the Cap and PAS domain of hERG3 in Escherichia coli and, using spectroscopy and kinetics, identified the PAS domain as the location for heme binding. The results identify heme as a regulator of hERG3 channel activity. These observations are discussed in the context of the emerging role for heme as a regulator of ion channel activity in cells.
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Affiliation(s)
- Mark J Burton
- Department of Chemistry, University of Leicester, Leicester, United Kingdom; Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, United Kingdom
| | | | - Morgan Thomas
- Department of Chemistry, University of Leicester, Leicester, United Kingdom; Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, United Kingdom
| | - Nicola Portolano
- Department of Chemistry, University of Leicester, Leicester, United Kingdom; Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, United Kingdom
| | - Jaswir Basran
- Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, United Kingdom; Department of Molecular and Cell Biology, University of Leicester, Leicester, United Kingdom
| | - Samuel L Freeman
- School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Hanna Kwon
- School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Andrew R Bottrill
- Protein Nucleic Acid Chemistry Laboratory, University of Leicester, Leicester, United Kingdom
| | - Manuel J Llansola-Portoles
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette, France
| | - Andrew A Pascal
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette, France
| | - Rebekah Jukes-Jones
- Medical Research Council Toxicology Unit, University of Cambridge, Leicester, United Kingdom
| | - Tatyana Chernova
- Medical Research Council Toxicology Unit, University of Cambridge, Leicester, United Kingdom
| | - Ralf Schmid
- Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, United Kingdom; Department of Molecular and Cell Biology, University of Leicester, Leicester, United Kingdom
| | - Noel W Davies
- Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, United Kingdom; Department of Molecular and Cell Biology, University of Leicester, Leicester, United Kingdom
| | - Nina M Storey
- Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester, United Kingdom; Department of Molecular and Cell Biology, University of Leicester, Leicester, United Kingdom
| | - Pierre Dorlet
- CNRS, Aix Marseille Université, Laboratoire de Bioenergetique et d'Ingenierie des Protéines, Marseille, France
| | - Peter C E Moody
- Department of Molecular and Cell Biology, University of Leicester, Leicester, United Kingdom
| | - John S Mitcheson
- Department of Molecular and Cell Biology, University of Leicester, Leicester, United Kingdom
| | - Emma L Raven
- School of Chemistry, University of Bristol, Bristol, United Kingdom.
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8
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Di Pietro C, Öz HH, Murray TS, Bruscia EM. Targeting the Heme Oxygenase 1/Carbon Monoxide Pathway to Resolve Lung Hyper-Inflammation and Restore a Regulated Immune Response in Cystic Fibrosis. Front Pharmacol 2020; 11:1059. [PMID: 32760278 PMCID: PMC7372134 DOI: 10.3389/fphar.2020.01059] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/30/2020] [Indexed: 12/11/2022] Open
Abstract
In individuals with cystic fibrosis (CF), lung hyper-inflammation starts early in life and is perpetuated by mucus obstruction and persistent bacterial infections. The continuous tissue damage and scarring caused by non-resolving inflammation leads to bronchiectasis and, ultimately, respiratory failure. Macrophages (MΦs) are key regulators of immune response and host defense. We and others have shown that, in CF, MΦs are hyper-inflammatory and exhibit reduced bactericidal activity. Thus, MΦs contribute to the inability of CF lung tissues to control the inflammatory response or restore tissue homeostasis. The non-resolving hyper-inflammation in CF lungs is attributed to an impairment of several signaling pathways associated with resolution of the inflammatory response, including the heme oxygenase-1/carbon monoxide (HO-1/CO) pathway. HO-1 is an enzyme that degrades heme groups, leading to the production of potent antioxidant, anti-inflammatory, and bactericidal mediators, such as biliverdin, bilirubin, and CO. This pathway is fundamental to re-establishing cellular homeostasis in response to various insults, such as oxidative stress and infection. Monocytes/MΦs rely on abundant induction of the HO-1/CO pathway for a controlled immune response and for potent bactericidal activity. Here, we discuss studies showing that blunted HO-1 activation in CF-affected cells contributes to hyper-inflammation and defective host defense against bacteria. We dissect potential cellular mechanisms that may lead to decreased HO-1 induction in CF cells. We review literature suggesting that induction of HO-1 may be beneficial for the treatment of CF lung disease. Finally, we discuss recent studies highlighting how endogenous HO-1 can be induced by administration of controlled doses of CO to reduce lung hyper-inflammation, oxidative stress, bacterial infection, and dysfunctional ion transport, which are all hallmarks of CF lung disease.
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Affiliation(s)
| | | | | | - Emanuela M. Bruscia
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT, United States
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9
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Reactive species generated by heme impair alveolar epithelial sodium channel function in acute respiratory distress syndrome. Redox Biol 2020; 36:101592. [PMID: 32506040 PMCID: PMC7276446 DOI: 10.1016/j.redox.2020.101592] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/08/2020] [Accepted: 05/20/2020] [Indexed: 12/19/2022] Open
Abstract
We previously reported that the highly reactive cell-free heme (CFH) is increased in the plasma of patients with chronic lung injury and causes pulmonary edema in animal model of acute respiratory distress syndrome (ARDS) post inhalation of halogen gas. However, the mechanisms by which CFH causes pulmonary edema are unclear. Herein we report for the first time that CFH and chlorinated lipids (formed by the interaction of halogen gas, Cl2, with plasmalogens) are increased in the plasma of patients exposed to Cl2 gas. Ex vivo incubation of red blood cells (RBC) with halogenated lipids caused oxidative damage to RBC cytoskeletal protein spectrin, resulting in hemolysis and release of CFH. Patch clamp and short circuit current measurements revealed that CFH inhibited the activity of amiloride-sensitive epithelial Na+ channel (ENaC) and cation sodium (Na+) channels in mouse alveolar cells and trans-epithelial Na+ transport across human airway cells with EC50 of 125 nM and 500 nM, respectively. Molecular modeling identified 22 putative heme-docking sites on ENaC (energy of binding range: 86-1563 kJ/mol) with at least 2 sites within its narrow transmembrane pore, potentially capable of blocking Na+ transport across the channel. A single intramuscular injection of the heme-scavenging protein, hemopexin (4 μg/kg body weight), one hour post halogen gas exposure, decreased plasma CFH and improved lung ENaC activity in mice. In conclusion, results suggested that CFH mediated inhibition of ENaC activity may be responsible for pulmonary edema post inhalation injury.
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10
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Drummond HA, Mitchell ZL, Abraham NG, Stec DE. Targeting Heme Oxygenase-1 in Cardiovascular and Kidney Disease. Antioxidants (Basel) 2019; 8:antiox8060181. [PMID: 31216709 PMCID: PMC6617021 DOI: 10.3390/antiox8060181] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 06/13/2019] [Accepted: 06/15/2019] [Indexed: 12/13/2022] Open
Abstract
Heme oxygenase (HO) plays an important role in the cardiovascular system. It is involved in many physiological and pathophysiological processes in all organs of the cardiovascular system. From the regulation of blood pressure and blood flow to the adaptive response to end-organ injury, HO plays a critical role in the ability of the cardiovascular system to respond and adapt to changes in homeostasis. There have been great advances in our understanding of the role of HO in the regulation of blood pressure and target organ injury in the last decade. Results from these studies demonstrate that targeting of the HO system could provide novel therapeutic opportunities for the treatment of several cardiovascular and renal diseases. The goal of this review is to highlight the important role of HO in the regulation of cardiovascular and renal function and protection from disease and to highlight areas in which targeting of the HO system needs to be translated to help benefit patient populations.
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Affiliation(s)
- Heather A Drummond
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MI 39216, USA.
| | - Zachary L Mitchell
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MI 39216, USA.
| | - Nader G Abraham
- Departments of Medicine and Pharmacology, New York Medical College, Vahalla, NY 10595, USA.
- Joan C. Edwards School of Medicine, Marshall University, Huntington, VA 25701, USA.
| | - David E Stec
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MI 39216, USA.
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11
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Ashley Z, Mugloo S, McDonald FJ, Fronius M. Epithelial Na + channel differentially contributes to shear stress-mediated vascular responsiveness in carotid and mesenteric arteries from mice. Am J Physiol Heart Circ Physiol 2018; 314:H1022-H1032. [PMID: 29373035 DOI: 10.1152/ajpheart.00506.2017] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A potential "new player" in arteries for mediating shear stress responses is the epithelial Na+ channel (ENaC). The contribution of ENaC as shear sensor in intact arteries, and particularly different types of arteries (conduit and resistance), is unknown. We investigated the role of ENaC in both conduit (carotid) and resistance (third-order mesenteric) arteries isolated from C57Bl/6J mice. Vessel characteristics were determined at baseline (60 mmHg, no flow) and in response to increased intraluminal pressure and shear stress using a pressure myograph. These protocols were performed in the absence and presence of the ENaC inhibitor amiloride (10 µM) and after inhibition of endothelial nitric oxide synthase (eNOS) by Nω-nitro-l-arginine methyl ester (l-NAME; 100 µM). Under no-flow conditions, amiloride increased internal and external diameters of carotid (13 ± 2%, P < 0.05) but not mesenteric (0.5 ± 0.9%, P > 0.05) arteries. In response to increased intraluminal pressure, amiloride had no effect on the internal diameter of either type of artery. However, amiloride affected the stress-strain curves of mesenteric arteries. With increased shear stress, ENaC-dependent effects were observed in both arteries. In carotid arteries, amiloride augmented flow-mediated dilation (9.2 ± 5.3%) compared with control (no amiloride, 6.2 ± 3.3%, P < 0.05). In mesenteric arteries, amiloride induced a flow-mediated constriction (-11.5 ± 6.6%) compared with control (-2.2 ± 4.5%, P < 0.05). l-NAME mimicked the effect of ENaC inhibition and prevented further amiloride effects in both types of arteries. These observations indicate that ENaC contributes to shear sensing in conduit and resistance arteries. ENaC-mediated effects were associated with NO production but may involve different (artery-dependent) downstream signaling pathways. NEW & NOTEWORTHY The epithelial Na+ channel (ENaC) contributes to shear sensing in conduit and resistance arteries. In conduit arteries ENaC has a role as a vasoconstrictor, whereas in resistance arteries ENaC contributes to vasodilation. Interaction of ENaC with endothelial nitric oxide synthase/nitric oxide signaling to mediate the effects is supported; however, cross talk with other shear stress-dependent signaling pathways cannot be excluded.
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Affiliation(s)
- Zoe Ashley
- Department of Physiology, University of Otago , Dunedin , New Zealand.,HeartOtago, University of Otago , Dunedin , New Zealand
| | - Sama Mugloo
- Department of Physiology, University of Otago , Dunedin , New Zealand.,HeartOtago, University of Otago , Dunedin , New Zealand
| | - Fiona J McDonald
- Department of Physiology, University of Otago , Dunedin , New Zealand
| | - Martin Fronius
- Department of Physiology, University of Otago , Dunedin , New Zealand.,HeartOtago, University of Otago , Dunedin , New Zealand
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12
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Ryter SW, Ma KC, Choi AMK. Carbon monoxide in lung cell physiology and disease. Am J Physiol Cell Physiol 2017; 314:C211-C227. [PMID: 29118026 DOI: 10.1152/ajpcell.00022.2017] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Carbon monoxide (CO) is an endogenously produced gas that has gained recognition as a biological signal transduction effector with properties similar, but not identical, to that of nitric oxide (NO). CO, which binds primarily to heme iron, may activate the hemoprotein guanylate cyclase, although with lower potency than NO. Furthermore, CO can modulate the activities of several cellular signaling molecules such as p38 MAPK, ERK1/2, JNK, Akt, NF-κB, and others. Emerging studies suggest that mitochondria, the energy-generating organelle of cells, represent a key target of CO action in eukaryotes. Dose-dependent modulation of mitochondrial function by CO can result in alteration of mitochondrial membrane potential, mitochondrial reactive oxygen species production, release of proapoptotic and proinflammatory mediators, as well as the inhibition of respiration at high concentration. CO, through modulation of signaling pathways, can impact key biological processes including autophagy, mitochondrial biogenesis, programmed cell death (apoptosis), cellular proliferation, inflammation, and innate immune responses. Inhaled CO is widely known as an inhalation hazard due to its rapid complexation with hemoglobin, resulting in impaired oxygen delivery to tissues and hypoxemia. Despite systemic and cellular toxicity at high concentrations, CO has demonstrated cyto- and tissue-protective effects at low concentration in animal models of organ injury and disease. These include models of acute lung injury (e.g., hyperoxia, hypoxia, ischemia-reperfusion, mechanical ventilation, bleomycin) and sepsis. The success of CO as a candidate therapeutic in preclinical models suggests potential clinical application in inflammatory and proliferative disorders, which is currently under evaluation in clinical trials.
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Affiliation(s)
- Stefan W Ryter
- Division of Pulmonary and Critical Care Medicine, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medical College , New York, New York
| | - Kevin C Ma
- Division of Pulmonary and Critical Care Medicine, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medical College , New York, New York.,New York Presbyterian Hospital , New York, New York
| | - Augustine M K Choi
- Division of Pulmonary and Critical Care Medicine, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medical College , New York, New York.,New York Presbyterian Hospital , New York, New York
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13
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Maignan M, Gennai S, Debaty G, Romanini D, Schmidt MH, Brenckmann V, Brouta A, Ventrillard I, Briot R. Exhaled carbon monoxide is correlated with ischemia reperfusion injuries during
ex vivo
lung perfusion in pigs. J Breath Res 2017. [DOI: 10.1088/1752-7163/aa7a73] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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14
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Wang G. Mechanistic insight into the heme-independent interplay between iron and carbon monoxide in CFTR and Slo1 BK Ca channels. Metallomics 2017; 9:634-645. [PMID: 28474046 DOI: 10.1039/c7mt00065k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ion channels have been extensively reported as effectors of carbon monoxide (CO). However, the mechanisms of heme-independent CO action are still not known. Because most ion channels are heterologously expressed on human embryonic kidney cells that are cultured in Fe3+-containing media, CO may act as a small and strong iron chelator to disrupt a putative iron bridge in ion channels and thus to tune their activity. In this review CFTR and Slo1 BKCa channels are employed to discuss the possible heme-independent interplay between iron and CO. Our recent studies demonstrated a high-affinity Fe3+ site at the interface between the regulatory domain and intracellular loop 3 of CFTR. Because the binding of Fe3+ to CFTR prevents channel opening, the stimulatory effect of CO on the Cl- and HCO3- currents across the apical membrane of rat distal colon may be due to the release of inhibitive Fe3+ by CO. In contrast, CO repeatedly stimulates the human Slo1 BKCa channel opening, possibly by binding to an unknown iron site, because cyanide prohibits this heme-independent CO stimulation. Here, in silico research on recent structural data of the slo1 BKCa channels indicates two putative binuclear Fe2+-binding motifs in the gating ring in which CO may compete with protein residues to bind to either Fe2+ bowl to disrupt the Fe2+ bridge but not to release Fe2+ from the channel. Thus, these two new regulation models of CO, with iron releasing from and retaining in the ion channel, may have significant and extensive implications for other metalloproteins.
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Affiliation(s)
- Guangyu Wang
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA, USA. and Institute of Biophysical Medico-chemistry, Reno, NV, USA
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15
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Trac PT, Thai TL, Linck V, Zou L, Greenlee M, Yue Q, Al-Khalili O, Alli AA, Eaton AF, Eaton DC. Alveolar nonselective channels are ASIC1a/α-ENaC channels and contribute to AFC. Am J Physiol Lung Cell Mol Physiol 2017; 312:L797-L811. [PMID: 28283476 DOI: 10.1152/ajplung.00379.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 03/01/2017] [Accepted: 03/02/2017] [Indexed: 12/13/2022] Open
Abstract
A thin fluid layer in alveoli is normal and results from a balance of fluid entry and fluid uptake by transepithelial salt and water reabsorption. Conventional wisdom suggests the reabsorption is via epithelial Na+ channels (ENaC), but if all Na+ reabsorption were via ENaC, then amiloride, an ENaC inhibitor, should block alveolar fluid clearance (AFC). However, amiloride blocks only half of AFC. The reason for failure to block is clear from single-channel measurements from alveolar epithelial cells: ENaC channels are observed, but another channel is present at the same frequency that is nonselective for Na+ over K+, has a larger conductance, and has shorter open and closed times. These two channel types are known as highly selective channels (HSC) and nonselective cation channels (NSC). HSC channels are made up of three ENaC subunits since knocking down any of the subunits reduces HSC number. NSC channels contain α-ENaC since knocking down α-ENaC reduces the number of NSC (knocking down β- or γ-ENaC has no effect on NSC, but the molecular composition of NSC channels remains unclear). We show that NSC channels consist of at least one α-ENaC and one or more acid-sensing ion channel 1a (ASIC1a) proteins. Knocking down either α-ENaC or ASIC1a reduces both NSC and HSC number, and no NSC channels are observable in single-channel patches on lung slices from ASIC1a knockout mice. AFC is reduced in knockout mice, and wet wt-to-dry wt ratio is increased, but the percentage increase in wet wt-to-dry wt ratio is larger than expected based on the reduction in AFC.
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Affiliation(s)
- Phi T Trac
- Department of Physiology and Center for Cell and Molecular Signaling, Emory University School of Medicine, Atlanta, Georgia; and
| | - Tiffany L Thai
- Department of Physiology and Center for Cell and Molecular Signaling, Emory University School of Medicine, Atlanta, Georgia; and
| | - Valerie Linck
- Department of Physiology and Center for Cell and Molecular Signaling, Emory University School of Medicine, Atlanta, Georgia; and
| | - Li Zou
- Department of Physiology and Center for Cell and Molecular Signaling, Emory University School of Medicine, Atlanta, Georgia; and
| | - Megan Greenlee
- Department of Physiology and Center for Cell and Molecular Signaling, Emory University School of Medicine, Atlanta, Georgia; and
| | - Qiang Yue
- Department of Physiology and Center for Cell and Molecular Signaling, Emory University School of Medicine, Atlanta, Georgia; and
| | - Otor Al-Khalili
- Department of Physiology and Center for Cell and Molecular Signaling, Emory University School of Medicine, Atlanta, Georgia; and
| | - Abdel A Alli
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Florida
| | - Amity F Eaton
- Department of Physiology and Center for Cell and Molecular Signaling, Emory University School of Medicine, Atlanta, Georgia; and
| | - Douglas C Eaton
- Department of Physiology and Center for Cell and Molecular Signaling, Emory University School of Medicine, Atlanta, Georgia; and
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16
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Motterlini R, Foresti R. Biological signaling by carbon monoxide and carbon monoxide-releasing molecules. Am J Physiol Cell Physiol 2017; 312:C302-C313. [DOI: 10.1152/ajpcell.00360.2016] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 01/09/2017] [Accepted: 01/09/2017] [Indexed: 02/02/2023]
Abstract
Carbon monoxide (CO) is continuously produced in mammalian cells during the degradation of heme. It is a stable gaseous molecule that reacts selectively with transition metals in a specific redox state, and these characteristics restrict the interaction of CO with defined biological targets that transduce its signaling activity. Because of the high affinity of CO for ferrous heme, these targets can be grouped into heme-containing proteins, representing a large variety of sensors and enzymes with a series of diverse function in the cell and the organism. Despite this notion, progress in identifying which of these targets are selective for CO has been slow and even the significance of elevated carbonmonoxy hemoglobin, a classical marker used to diagnose CO poisoning, is not well understood. This is also due to the lack of technologies capable of assessing in a comprehensive fashion the distribution and local levels of CO between the blood circulation, the tissue, and the mitochondria, one of the cellular compartments where CO exerts its signaling or detrimental effects. Nevertheless, the use of CO gas and CO-releasing molecules as pharmacological approaches in models of disease has provided new important information about the signaling properties of CO. In this review we will analyze the most salient effects of CO in biology and discuss how the binding of CO with key ferrous hemoproteins serves as a posttranslational modification that regulates important processes as diverse as aerobic metabolism, oxidative stress, and mitochondrial bioenergetics.
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Affiliation(s)
- Roberto Motterlini
- Inserm U955, Team 12, Créteil, France; and Faculty of Medicine, Université Paris Est, Créteil, France
| | - Roberta Foresti
- Inserm U955, Team 12, Créteil, France; and Faculty of Medicine, Université Paris Est, Créteil, France
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17
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Su Z, Zhu L, Wu J, Zhao R, Ji HL. Systematic review and meta-analysis of nasal potential difference in hypoxia-induced lung injury. Sci Rep 2016; 6:30780. [PMID: 27488696 PMCID: PMC4973263 DOI: 10.1038/srep30780] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/07/2016] [Indexed: 12/27/2022] Open
Abstract
Nasal potential difference (NPD), a well-established in vivo clinical test for cystic fibrosis, reflects transepithelial cation and anion transport in the respiratory epithelium. To analyze whether NPD can be applied to diagnose hypoxic lung injury, we searched PubMed, EMBASE, Scopus, Web of Science, Ovid MEDLINE, and Google Scholar, and analyzed data retrieved from eleven unbiased studies for high altitude pulmonary edema (HAPE) and respiratory distress syndrome (RDS) using the software RevMan and R. There was a significant reduction in overall basal (WMD -5.27 mV, 95% CI: -6.03 to -4.52, P < 0.00001, I(2) = 42%), amiloride-sensitive (ENaC) (-2.87 mV, 95% CI: -4.02 to -1.72, P < 0.00001, I(2) = 51%), and -resistant fractions (-3.91 mV, 95% CI: -7.64 to -0.18, P = 0.04, I(2) = 95%) in lung injury patients. Further analysis of HAPE and RDS separately corroborated these observations. Moreover, SpO2 correlated with ENaC-associated NPD positively in patients only, but apparently related to CFTR-contributed NPD level inversely. These correlations were confirmed by the opposite associations between NPD values and altitude, which had a negative regression with SpO2 level. Basal NPD was significantly associated with amiloride-resistant but not ENaC fraction. Our analyses demonstrate that acute lung injury associated with systemic hypoxia is characterized by dysfunctional NPD.
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Affiliation(s)
- Zhenlei Su
- Institute of Lung and Molecular Therapy, Xinxiang Medical University, Xinxiang Henan 453003, China.,School of Public Health, Xinxiang Medical University, Xinxiang Henan, 453003, China
| | - Lili Zhu
- School of Nursing, Xinxiang Medical University, Xinxiang Henan 453003, China
| | - Jing Wu
- Institute of Lung and Molecular Therapy, Xinxiang Medical University, Xinxiang Henan 453003, China
| | - Runzhen Zhao
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas, 75708, USA
| | - Hong-Long Ji
- Department of Cellular and Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, Texas, 75708, USA.,Texas Lung Injury Institute, University of Texas Health Science Center at Tyler, Tyler, Texas, 75708, USA
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18
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A heme-binding domain controls regulation of ATP-dependent potassium channels. Proc Natl Acad Sci U S A 2016; 113:3785-90. [PMID: 27006498 DOI: 10.1073/pnas.1600211113] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Heme iron has many and varied roles in biology. Most commonly it binds as a prosthetic group to proteins, and it has been widely supposed and amply demonstrated that subtle variations in the protein structure around the heme, including the heme ligands, are used to control the reactivity of the metal ion. However, the role of heme in biology now appears to also include a regulatory responsibility in the cell; this includes regulation of ion channel function. In this work, we show that cardiac KATP channels are regulated by heme. We identify a cytoplasmic heme-binding CXXHX16H motif on the sulphonylurea receptor subunit of the channel, and mutagenesis together with quantitative and spectroscopic analyses of heme-binding and single channel experiments identified Cys628 and His648 as important for heme binding. We discuss the wider implications of these findings and we use the information to present hypotheses for mechanisms of heme-dependent regulation across other ion channels.
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19
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A holistic view of cancer bioenergetics: mitochondrial function and respiration play fundamental roles in the development and progression of diverse tumors. Clin Transl Med 2016; 5:3. [PMID: 26812134 PMCID: PMC4728164 DOI: 10.1186/s40169-016-0082-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 01/11/2016] [Indexed: 02/01/2023] Open
Abstract
Since Otto Warburg made the first observation that tumor cells exhibit altered metabolism and bioenergetics in the 1920s, many scientists have tried to further the understanding of tumor bioenergetics. Particularly, in the past decade, the application of the state-of the-art metabolomics and genomics technologies has revealed the remarkable plasticity of tumor metabolism and bioenergetics. Firstly, a wide array of tumor cells have been shown to be able to use not only glucose, but also glutamine for generating cellular energy, reducing power, and metabolic building blocks for biosynthesis. Secondly, many types of cancer cells generate most of their cellular energy via mitochondrial respiration and oxidative phosphorylation. Glutamine is the preferred substrate for oxidative phosphorylation in tumor cells. Thirdly, tumor cells exhibit remarkable versatility in using bioenergetics substrates. Notably, tumor cells can use metabolic substrates donated by stromal cells for cellular energy generation via oxidative phosphorylation. Further, it has been shown that mitochondrial transfer is a critical mechanism for tumor cells with defective mitochondria to restore oxidative phosphorylation. The restoration is necessary for tumor cells to gain tumorigenic and metastatic potential. It is also worth noting that heme is essential for the biogenesis and proper functioning of mitochondrial respiratory chain complexes. Hence, it is not surprising that recent experimental data showed that heme flux and function are elevated in non-small cell lung cancer (NSCLC) cells and that elevated heme function promotes intensified oxygen consumption, thereby fueling tumor cell proliferation and function. Finally, emerging evidence increasingly suggests that clonal evolution and tumor genetic heterogeneity contribute to bioenergetic versatility of tumor cells, as well as tumor recurrence and drug resistance. Although mutations are found only in several metabolic enzymes in tumors, diverse mutations in signaling pathways and networks can cause changes in the expression and activity of metabolic enzymes, which likely enable tumor cells to gain their bioenergetic versatility. A better understanding of tumor bioenergetics should provide a more holistic approach to investigate cancer biology and therapeutics. This review therefore attempts to comprehensively consider and summarize the experimental data supporting our latest view of cancer bioenergetics.
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20
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Estes S, Zhong L, Artinian L, Rehder V. Regulation of electrical activity and neuronal excitability in Helisoma trivolvis by carbon monoxide. Neuroscience 2015; 311:453-63. [DOI: 10.1016/j.neuroscience.2015.10.056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 10/23/2015] [Accepted: 10/28/2015] [Indexed: 11/30/2022]
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21
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Roderique JD, Josef CS, Feldman MJ, Spiess BD. A modern literature review of carbon monoxide poisoning theories, therapies, and potential targets for therapy advancement. Toxicology 2015; 334:45-58. [PMID: 25997893 DOI: 10.1016/j.tox.2015.05.004] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 05/01/2015] [Accepted: 05/12/2015] [Indexed: 01/03/2023]
Abstract
The first descriptions of carbon monoxide (CO) and its toxic nature appeared in the literature over 100 years ago in separate publications by Drs. Douglas and Haldane. Both men ascribed the deleterious effects of this newly discovered gas to its strong interaction with hemoglobin. Since then the adverse sequelae of CO poisoning has been almost universally attributed to hypoxic injury secondary to CO occupation of oxygen binding sites on hemoglobin. Despite a mounting body of literature suggesting other mechanisms of injury, this pathophysiology and its associated oxygen centric therapies persists. This review attempts to elucidate the remarkably complex nature of CO as a gasotransmitter. While CO's affinity for hemoglobin remains undisputed, new research suggests that its role in nitric oxide release, reactive oxygen species formation, and its direct action on ion channels is much more significant. In the course of understanding the multifaceted character of this simple molecule it becomes apparent that current oxygen based therapies meant to displace CO from hemoglobin may be insufficient and possibly harmful. Approaching CO as a complex gasotransmitter will help guide understanding of the complex and poorly understood sequelae and illuminate potentials for new treatment modalities.
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Affiliation(s)
- Joseph D Roderique
- Department of Anesthesiology, VCU School of Medicine Sanger Hall, Rm B1-016, 1101 East Marshall Street, P.O. Box 980695, Richmond, VA 23298, United States
| | - Christopher S Josef
- Department of Anesthesiology, VCU School of Medicine Sanger Hall, Rm B1-016, 1101 East Marshall Street, P.O. Box 980695, Richmond, VA 23298, United States.
| | - Michael J Feldman
- Department of Plastic and Reconstructive Surgery, Critical Care Hospital 8th floor, 1213 East Clay St, Richmond, VA 23298, United States
| | - Bruce D Spiess
- Department of Anesthesiology, VCU School of Medicine Sanger Hall, Rm B1-016, 1101 East Marshall Street, P.O. Box 980695, Richmond, VA 23298, United States
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22
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Peers C, Boyle JP, Scragg JL, Dallas ML, Al-Owais MM, Hettiarachichi NT, Elies J, Johnson E, Gamper N, Steele DS. Diverse mechanisms underlying the regulation of ion channels by carbon monoxide. Br J Pharmacol 2015; 172:1546-56. [PMID: 24818840 PMCID: PMC4369263 DOI: 10.1111/bph.12760] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 04/14/2014] [Accepted: 04/21/2014] [Indexed: 12/19/2022] Open
Abstract
Carbon monoxide (CO) is firmly established as an important, physiological signalling molecule as well as a potent toxin. Through its ability to bind metal-containing proteins, it is known to interfere with a number of intracellular signalling pathways, and such actions can account for its physiological and pathological effects. In particular, CO can modulate the intracellular production of reactive oxygen species, NO and cGMP levels, as well as regulate MAPK signalling. In this review, we consider ion channels as more recently discovered effectors of CO signalling. CO is now known to regulate a growing number of different ion channel types, and detailed studies of the underlying mechanisms of action are revealing unexpected findings. For example, there are clear areas of contention surrounding its ability to increase the activity of high conductance, Ca(2+) -sensitive K(+) channels. More recent studies have revealed the ability of CO to inhibit T-type Ca(2+) channels and have unveiled a novel signalling pathway underlying tonic regulation of this channel. It is clear that the investigation of ion channels as effectors of CO signalling is in its infancy, and much more work is required to fully understand both the physiological and the toxic actions of this gas. Only then can its emerging use as a therapeutic tool be fully and safely exploited.
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Affiliation(s)
- C Peers
- Division of Cardiovascular and Diabetes Research, LIGHT, Faculty of Medicine and Health, University of LeedsLeeds, UK
| | - J P Boyle
- Division of Cardiovascular and Diabetes Research, LIGHT, Faculty of Medicine and Health, University of LeedsLeeds, UK
| | - J L Scragg
- Division of Cardiovascular and Diabetes Research, LIGHT, Faculty of Medicine and Health, University of LeedsLeeds, UK
| | - M L Dallas
- School of Pharmacy, University of ReadingReading, UK
| | - M M Al-Owais
- Division of Cardiovascular and Diabetes Research, LIGHT, Faculty of Medicine and Health, University of LeedsLeeds, UK
| | - N T Hettiarachichi
- Division of Cardiovascular and Diabetes Research, LIGHT, Faculty of Medicine and Health, University of LeedsLeeds, UK
| | - J Elies
- Division of Cardiovascular and Diabetes Research, LIGHT, Faculty of Medicine and Health, University of LeedsLeeds, UK
| | - E Johnson
- Division of Cardiovascular and Diabetes Research, LIGHT, Faculty of Medicine and Health, University of LeedsLeeds, UK
| | - N Gamper
- Faculty of Biological Sciences, University of LeedsLeeds, UK
| | - D S Steele
- Faculty of Biological Sciences, University of LeedsLeeds, UK
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23
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Levitt DG, Levitt MD. Carbon monoxide: a critical quantitative analysis and review of the extent and limitations of its second messenger function. Clin Pharmacol 2015; 7:37-56. [PMID: 25750547 PMCID: PMC4348054 DOI: 10.2147/cpaa.s79626] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Endogenously produced carbon monoxide (CO) is commonly believed to be a ubiquitous second messenger involved in a wide range of physiological and pathological responses. The major evidence supporting this concept is that CO is produced endogenously via heme oxygenase-catalyzed breakdown of heme and that experimental exposure to CO alters tissue function. However, it remains to be conclusively demonstrated that there are specific receptors for CO and that endogenous CO production is sufficient to alter tissue function. Unlike other signaling molecules, CO is not significantly metabolized, and it is removed from cells solely via rapid diffusion into blood, which serves as a near infinite sink. This non-metabolizable nature of CO renders the physiology of this gas uniquely susceptible to quantitative modeling. This review analyzes each of the steps involved in CO signaling: 1) the background CO partial pressure (PCO) and the blood and tissue CO binding; 2) the affinity of the putative CO receptors; 3) the rate of endogenous tissue CO production; and 4) the tissue PCO that results from the balance between this endogenous CO production and diffusion to the blood sink. Because existing data demonstrate that virtually all endogenous CO production results from the routine "housekeeping" turnover of heme, only a small fraction can play a signaling role. The novel aspect of the present report is to demonstrate via physiological modeling that this small fraction of CO production is seemingly insufficient to raise intracellular PCO to the levels required for the conventional, specific messenger receptor activation. It is concluded that the many physiological alterations observed with exogenous CO administration are probably produced by the non-specific CO inhibition of cytochrome C oxidase activity, with release of reactive oxygen species (ROS) and that this ROS signaling pathway is a potential effector mechanism for endogenously produced CO.
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Affiliation(s)
- David G Levitt
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Michael D Levitt
- Research Service, Veterans Affairs Medical Center, Minneapolis, MN, USA
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24
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Abstract
Genetic variants in haem metabolism enzymes can be predisposition factors for adverse reactions in some individuals. New areas of haem biology may also be associated with idiosyncratic effects which are yet to be identified.
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Affiliation(s)
- Viktoria Vágány
- MRC Toxicology Unit
- Hodgkin Building
- University of Leicester
- Leicester LE1 9HN
- UK
| | - Andrew G. Smith
- MRC Toxicology Unit
- Hodgkin Building
- University of Leicester
- Leicester LE1 9HN
- UK
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25
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Carbon monoxide inhibits inward rectifier potassium channels in cardiomyocytes. Nat Commun 2014; 5:4676. [PMID: 25118981 DOI: 10.1038/ncomms5676] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 07/13/2014] [Indexed: 11/09/2022] Open
Abstract
Reperfusion-induced ventricular fibrillation (VF) severely threatens the lives of post-myocardial infarction patients. Carbon monoxide (CO)--produced by haem oxygenase in cardiomyocytes--has been reported to prevent VF through an unknown mechanism of action. Here, we report that CO prolongs action potential duration (APD) by inhibiting a subset of inward-rectifying potassium (Kir) channels. We show that CO blocks Kir2.2 and Kir2.3 but not Kir2.1 channels in both cardiomyocytes and HEK-293 cells transfected with Kir. CO directly inhibits Kir2.3 by interfering with its interaction with the second messenger phosphatidylinositol (4,5)-bisphosphate (PIP2). As the inhibition of Kir2.2 and Kir2.3 by CO prolongs APD in myocytes, cardiac Kir2.2 and Kir2.3 are promising targets for the prevention of reperfusion-induced VF.
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26
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Heinemann SH, Hoshi T, Westerhausen M, Schiller A. Carbon monoxide--physiology, detection and controlled release. Chem Commun (Camb) 2014; 50:3644-60. [PMID: 24556640 PMCID: PMC4072318 DOI: 10.1039/c3cc49196j] [Citation(s) in RCA: 291] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Carbon monoxide (CO) is increasingly recognized as a cell-signalling molecule akin to nitric oxide (NO). CO has attracted particular attention as a potential therapeutic agent because of its reported anti-hypertensive, anti-inflammatory and cell-protective effects. We discuss recent progress in identifying new effector systems and elucidating the mechanisms of action of CO on, e.g., ion channels, as well as the design of novel methods to monitor CO in cellular environments. We also report on recent developments in the area of CO-releasing molecules (CORMs) and materials for controlled CO application. Novel triggers for CO release, metal carbonyls and degradation mechanisms of CORMs are highlighted. In addition, potential formulations of CORMs for targeted CO release are discussed.
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Affiliation(s)
- Stefan H. Heinemann
- Center for Molecular Biomedicine (CMB), Department of Biophysics, Friedrich Schiller University Jena & Jena University Hospital, Hans-Knöll-Straße 2, D-07745 Jena, Germany
| | - Toshinori Hoshi
- Department of Physiology, University of Pennsylvania, 415 Curie Boulevard, 605 CRB, Philadelphia, PA 19104-6085, USA
| | - Matthias Westerhausen
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstr. 8, D-07743 Jena, Germany
| | - Alexander Schiller
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstr. 8, D-07743 Jena, Germany
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27
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Warrington JP, Coleman K, Skaggs C, Hosick PA, George EM, Stec DE, Ryan MJ, Granger JP, Drummond HA. Heme oxygenase-1 promotes migration and β-epithelial Na+ channel expression in cytotrophoblasts and ischemic placentas. Am J Physiol Regul Integr Comp Physiol 2014; 306:R641-6. [PMID: 24553299 DOI: 10.1152/ajpregu.00566.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Preeclampsia is thought to arise from inadequate cytotrophoblast migration and invasion of the maternal spiral arteries, resulting in placental ischemia and hypertension. Evidence suggests that altered expression of epithelial Na(+) channel (ENaC) proteins may be a contributing mechanism for impaired cytotrophoblast migration. ENaC activity is required for normal cytotrophoblast migration. Moreover, β-ENaC, the most robustly expressed placental ENaC message, is reduced in placentas from preeclamptic women. We recently demonstrated that heme oxygenase-1 (HO-1) protects against hypertension in a rat model of placental ischemia; however, whether HO-1 regulation of β-ENaC contributes to the beneficial effects of HO-1 is unknown. The purpose of this study was to determine whether β-ENaC mediates cytotrophoblast migration and whether HO-1 enhances ENaC-mediated migration. We showed that placental ischemia, induced by reducing uterine perfusion suppressed, and HO-1 induction restored, β-ENaC expression in ischemic placentas. Using an in vitro model, we found that HO-1 induction, using cobalt protoporphyrin, stimulates cytotrophoblast β-ENaC expression by 1.5- and 1.8-fold (10 and 50 μM). We then showed that silencing of β-ENaC in cultured cytotrophoblasts (BeWo cells), by expression of dominant-negative constructs, reduced migration to 56 ± 13% (P < 0.05) of control. Importantly, HO-1 induction enhanced migration (43 ± 5% of control, P < 0.05), but the enhanced migratory response was entirely blocked by ENaC inhibition with amiloride (10 μM). Taken together, our results suggest that β-ENaC mediates cytotrophoblast migration and increasing β-ENaC expression by HO-1 induction enhances migration. HO-1 regulation of cytotrophoblast β-ENaC expression and migration may be a potential therapeutic target in preeclamptic patients.
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Affiliation(s)
- Junie P Warrington
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
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Abstract
Fine-tuned regulation of K(+) channel inactivation enables excitable cells to adjust action potential firing. Fast inactivation present in some K(+) channels is mediated by the distal N-terminal structure (ball) occluding the ion permeation pathway. Here we show that Kv1.4 K(+) channels are potently regulated by intracellular free heme; heme binds to the N-terminal inactivation domain and thereby impairs the inactivation process, thus enhancing the K(+) current with an apparent EC50 value of ∼20 nM. Functional studies on channel mutants and structural investigations on recombinant inactivation ball domain peptides encompassing the first 61 residues of Kv1.4 revealed a heme-responsive binding motif involving Cys13:His16 and a secondary histidine at position 35. Heme binding to the N-terminal inactivation domain induces a conformational constraint that prevents it from reaching its receptor site at the vestibule of the channel pore.
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Khan AA, Quigley JG. Heme and FLVCR-related transporter families SLC48 and SLC49. Mol Aspects Med 2013; 34:669-82. [PMID: 23506900 DOI: 10.1016/j.mam.2012.07.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 03/14/2012] [Indexed: 12/11/2022]
Abstract
Heme is critical for a variety of cellular processes, but excess intracellular heme may result in oxidative stress and membrane injury. Feline leukemia virus subgroup C receptor (FLVCR1), a member of the SLC49 family of four paralogous genes, is a cell surface heme exporter, essential for erythropoiesis and systemic iron homeostasis. Disruption of FLVCR1 function blocks development of erythroid progenitors, likely due to heme toxicity. Mutations of SLC49A1 encoding FLVCR1 are noted in patients with a rare neurodegenerative disorder: posterior column ataxia with retinitis pigmentosa. FLVCR2 is highly homologous to FLVCR1 and may function as a cellular heme importer. Mutations of SLC49A2 encoding FLVCR2 are observed in Fowler syndrome, a rare proliferative vascular disorder of the brain. The functions of the remaining members of the SLC49 family, MFSD7 and DIRC2 (encoded by the SLC49A3 and SLC49A4 genes), are unknown, although the latter is implicated in hereditary renal carcinomas. SLC48A1 (heme responsive gene-1, HRG-1), the sole member of the SLC48 family, is associated with the endosome and appears to transport heme from the endosome into the cytosol.
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Affiliation(s)
- Anwar A Khan
- Department of Medicine, Section of Hematology/Oncology, University of Illinois at Chicago, Chicago, IL, USA.
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Althaus M. Gasotransmitters: novel regulators of epithelial na(+) transport? Front Physiol 2012; 3:83. [PMID: 22509167 PMCID: PMC3321473 DOI: 10.3389/fphys.2012.00083] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 03/20/2012] [Indexed: 11/13/2022] Open
Abstract
The vectorial transport of Na(+) across epithelia is crucial for the maintenance of Na(+) and water homeostasis in organs such as the kidneys, lung, or intestine. Dysregulated Na(+) transport processes are associated with various human diseases such as hypertension, the salt-wasting syndrome pseudohypoaldosteronism type 1, pulmonary edema, cystic fibrosis, or intestinal disorders, which indicate that a precise regulation of epithelial Na(+) transport is essential. Novel regulatory signaling molecules are gasotransmitters. There are currently three known gasotransmitters: nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H(2)S). These molecules are endogenously produced in mammalian cells by specific enzymes and have been shown to regulate various physiological processes. There is a growing body of evidence which indicates that gasotransmitters may also regulate Na(+) transport across epithelia. This review will summarize the available data concerning NO, CO, and H(2)S dependent regulation of epithelial Na(+) transport processes and will discuss whether or not these mediators can be considered as true physiological regulators of epithelial Na(+) transport biology.
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Affiliation(s)
- Mike Althaus
- Institute of Animal Physiology, Justus Liebig University of Giessen Giessen, Germany
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Abstract
Our understanding of carbon monoxide (CO) as an endogenous signalling molecule has expanded enormously in recent years, to the point where it can now be safely exploited therapeutically. In more recent years, the ability of CO to modulate ion channel activity has added further diversity to its activity. Here, I summarize briefly the established ion channel targets of CO and describe in more detail its actions on two example ion channels (the cardiac L-type Ca(2+) channel and the neuronal delayed rectifier, Kv2.1). The physiological consequences of such modulation are also considered. It is clear that our knowledge of the cellular effects of this gas is incomplete, and further study is required to further understand and so more fully exploit its therapeutic potential.
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Affiliation(s)
- Chris Peers
- Division of Cardiovascular and Neuronal Remodelling, Faculty of Medicine and Health, University of Leeds, LS2 9JT, UK.
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32
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Khan AA, Quigley JG. Control of intracellular heme levels: heme transporters and heme oxygenases. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1813:668-82. [PMID: 21238504 PMCID: PMC3079059 DOI: 10.1016/j.bbamcr.2011.01.008] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2010] [Revised: 12/31/2010] [Accepted: 01/06/2011] [Indexed: 12/19/2022]
Abstract
Heme serves as a co-factor in proteins involved in fundamental biological processes including oxidative metabolism, oxygen storage and transport, signal transduction and drug metabolism. In addition, heme is important for systemic iron homeostasis in mammals. Heme has important regulatory roles in cell biology, yet excessive levels of intracellular heme are toxic; thus, mechanisms have evolved to control the acquisition, synthesis, catabolism and expulsion of cellular heme. Recently, a number of transporters of heme and heme synthesis intermediates have been described. Here we review aspects of heme metabolism and discuss our current understanding of heme transporters, with emphasis on the function of the cell-surface heme exporter, FLVCR. Knockdown of Flvcr in mice leads to both defective erythropoiesis and disturbed systemic iron homeostasis, underscoring the critical role of heme transporters in mammalian physiology. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
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Affiliation(s)
- Anwar A. Khan
- Department of Medicine, Section of Hematology/Oncology, University of Illinois College of Medicine, 909 South Wolcott Avenue, Chicago, IL-60612
| | - John G. Quigley
- Department of Medicine, Section of Hematology/Oncology, University of Illinois College of Medicine, 909 South Wolcott Avenue, Chicago, IL-60612
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Abstract
Carbon monoxide is rapidly emerging as an important cellular messenger, regulating a wide range of physiological processes. Crucial to its role in both physiology and disease is its ability differentially to regulate several classes of ion channels, including examples from calcium-activated K(+) (BK(Ca)), voltage-activated K(+) (K(v)) and Ca(2+) channel (L-type) families, ligand-gated P2X receptors (P2X2 and P2X4), tandem P domain K(+) channels (TREK1) and the epithelial Na(+) channel (ENaC). The mechanisms by which CO regulates these ion channels are still unclear and remain somewhat controversial. However, available structure-function studies suggest that a limited range of amino acid residues confer CO sensitivity, either directly or indirectly, to particular ion channels and that cellular redox state appears to be important to the final integrated response. Whatever the molecular mechanism by which CO regulates ion channels, endogenous production of this gasotransmitter has physiologically important roles and is currently being explored as a potential therapeutic.
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Affiliation(s)
- William J Wilkinson
- Division of Pathophysiology and Repair, School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
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Husted RF, Lu H, Sigmund RD, Stokes JB. Oxygen regulation of the epithelial Na channel in the collecting duct. Am J Physiol Renal Physiol 2010; 300:F412-24. [PMID: 21123494 DOI: 10.1152/ajprenal.00245.2010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The PO(2) within the kidney changes dramatically from cortex to medulla. The present experiments examined the effect of changing PO(2) on epithelial Na channel (ENaC)-mediated Na transport in the collecting duct using the mpkCCD-c14 cell line. Decreasing ambient O(2) concentration from 20 to 8% decreased ENaC activity by 40%; increasing O(2) content to 40% increased ENaC activity by 50%. The O(2) effect required several hours to develop and was not mimicked by the acid pH that developed in monolayers incubated in low-O(2) medium. Corticosteroids increased ENaC activity at each O(2) concentration; there was no interaction. The pathways for O(2) and steroid regulation of ENaC are different since O(2) did not substantially affect Sgk1, α-ENaC, Gilz, or Usp2-45 mRNA levels, genes involved in steroid-mediated ENaC regulation. The regulation of ENaC activity by these levels of O(2) appears not to be mediated by changes in hypoxia-inducible factor-1α or -2α activity or a change in AMP kinase activity. Changes in O(2) concentration had minimal effect on α- or γ-ENaC mRNA and protein levels; there were moderate effects on β-ENaC levels. However, 40% O(2) induced substantially greater total β- and γ-ENaC on the apical surface compared with 8% O(2); both subunits demonstrated a greater increase in the mature forms. The α-ENaC subunit was difficult to detect on the apical surface, perhaps because our antibodies do not recognize the major mature form. These results identify a mechanism of ENaC regulation that may be important in different regions of the kidney and in responses to changes in dietary NaCl.
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Affiliation(s)
- Russell F Husted
- Fraternal Order of Eagles Diabetes Research Center, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
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Mac Sweeney R, Fischer H, McAuley DF. Nasal potential difference to detect Na+ channel dysfunction in acute lung injury. Am J Physiol Lung Cell Mol Physiol 2010; 300:L305-18. [PMID: 21112943 DOI: 10.1152/ajplung.00223.2010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Pulmonary fluid clearance is regulated by the active transport of Na(+) and Cl(-) through respiratory epithelial ion channels. Ion channel dysfunction contributes to the pathogenesis of various pulmonary fluid disorders including high-altitude pulmonary edema (HAPE) and neonatal respiratory distress syndrome (RDS). Nasal potential difference (NPD) measurement allows an in vivo investigation of the functionality of these channels. This technique has been used for the diagnosis of cystic fibrosis, the archetypal respiratory ion channel disorder, for over a quarter of a century. NPD measurements in HAPE and RDS suggest constitutive and acquired dysfunction of respiratory epithelial Na(+) channels. Acute lung injury (ALI) is characterized by pulmonary edema due to alveolar epithelial-interstitial-endothelial injury. NPD measurement may enable identification of critically ill ALI patients with a susceptible phenotype of dysfunctional respiratory Na(+) channels and allow targeted therapy toward Na(+) channel function.
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Affiliation(s)
- R Mac Sweeney
- Respiratory Medicine Research Programme, Centre for Infection and Immunity, Queen’s University, Belfast, Northern Ireland
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Wilson MR, O'Dea KP, Dorr AD, Yamamoto H, Goddard ME, Takata M. Efficacy and safety of inhaled carbon monoxide during pulmonary inflammation in mice. PLoS One 2010; 5:e11565. [PMID: 20644637 PMCID: PMC2903490 DOI: 10.1371/journal.pone.0011565] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 06/19/2010] [Indexed: 12/05/2022] Open
Abstract
Background Pulmonary inflammation is a major contributor to morbidity in a variety of respiratory disorders, but treatment options are limited. Here we investigate the efficacy, safety and mechanism of action of low dose inhaled carbon monoxide (CO) using a mouse model of lipopolysaccharide (LPS)-induced pulmonary inflammation. Methodology Mice were exposed to 0–500 ppm inhaled CO for periods of up to 24 hours prior to and following intratracheal instillation of 10 ng LPS. Animals were sacrificed and assessed for intraalveolar neutrophil influx and cytokine levels, flow cytometric determination of neutrophil number and activation in blood, lung and lavage fluid samples, or neutrophil mobilisation from bone marrow. Principal Findings When administered for 24 hours both before and after LPS, inhaled CO of 100 ppm or more reduced intraalveolar neutrophil infiltration by 40–50%, although doses above 100 ppm were associated with either high carboxyhemoglobin, weight loss or reduced physical activity. This anti-inflammatory effect of CO did not require pre-exposure before induction of injury. 100 ppm CO exposure attenuated neutrophil sequestration within the pulmonary vasculature as well as LPS-induced neutrophilia at 6 hours after LPS, likely due to abrogation of neutrophil mobilisation from bone marrow. In contrast to such apparently beneficial effects, 100 ppm inhaled CO induced an increase in pulmonary barrier permeability as determined by lavage fluid protein content and translocation of labelled albumin from blood to the alveolar space. Conclusions Overall, these data confirm some protective role for inhaled CO during pulmonary inflammation, although this required a dose that produced carboxyhemoglobin values close to potentially toxic levels for humans, and increased lung permeability.
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Affiliation(s)
- Michael R Wilson
- Anaesthetics, Pain Medicine and Intensive Care, Imperial College London, Chelsea and Westminster Hospital, London, UK.
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Althaus M, Pichl A, Clauss WG, Seeger W, Fronius M, Morty RE. Nitric oxide inhibits highly selective sodium channels and the Na+/K+-ATPase in H441 cells. Am J Respir Cell Mol Biol 2010; 44:53-65. [PMID: 20139350 DOI: 10.1165/2009-0335oc] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Nitric oxide (NO) is an important regulator of Na(+) reabsorption by pulmonary epithelial cells and therefore of alveolar fluid clearance. The mechanisms by which NO affects epithelial ion transport are poorly understood and vary from model to model. In this study, the effects of NO on sodium reabsorption by H441 cell monolayers were studied in an Ussing chamber. Two NO donors, (Z)-1-[N-(3-aminopropyl)-N-(n-propyl)amino]diazen-1-ium-1,2-diolate and diethylammonium (Z)-1-(N,N-diethylamino)diazen-1-ium-1,2-diolate, rapidly, reversibly, and dose-dependently reduced amiloride-sensitive, short-circuit currents across H441 cell monolayers. This effect was neutralized by the NO scavenger hemoglobin and was not observed with inactive NO donors. The effects of NO were not blocked by 8-bromoguanosine-3',5'-cyclic monophosphate or by soluble guanylate cyclase inhibitors (methylene blue and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one) and were therefore independent of soluble guanylate cyclase signaling. NO targeted apical, highly selective, amiloride-sensitive Na(+) channels in basolaterally permeabilized H441 cell monolayers. NO had no effect on the activity of the human epithelial sodium channel heterologously expressed in Xenopus oocytes. NO decreased Na(+)/K(+)-ATPase activity in apically permeabilized H441 cell monolayers. The inhibition of Na(+)/K(+)-ATPase activity by NO was reversed by mercury and was mimicked by N-ethylmaleimide, which are agents that reverse and mimic, respectively, the reaction of NO with thiol groups. Consistent with these data, S-NO groups were detected on the Na(+)/K(+)-ATPase α subunit in response to NO-donor application, using a biotin-switch approach coupled to a Western blot. These data demonstrate that, in the H441 cell model, NO impairs Na(+) reabsorption by interfering with the activity of highly selective Na(+) channels and the Na(+)/K(+)-ATPase.
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Affiliation(s)
- Mike Althaus
- Department of Internal Medicine (Pulmonology), University of Giessen Lung Center, Justus Liebig University, Giessen, Germany
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Kemp PJ, Telezhkin V, Wilkinson WJ, Mears R, Hanmer SB, Gadeberg HC, Müller CT, Riccardi D, Brazier SP. Enzyme-Linked Oxygen Sensing by Potassium Channels. Ann N Y Acad Sci 2009; 1177:112-8. [DOI: 10.1111/j.1749-6632.2009.05025.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Affiliation(s)
- Scott Severance
- Department of Animal & Avian Sciences and Department of Cell Biology & Molecular Genetics, University of Maryland, College Park, Maryland 20742, USA
| | - Iqbal Hamza
- Department of Animal & Avian Sciences and Department of Cell Biology & Molecular Genetics, University of Maryland, College Park, Maryland 20742, USA
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Affiliation(s)
- Scott Severance
- Department of Animal & Avian Sciences, University of Maryland, College Park, Maryland 20742, USA
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