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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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2
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Olson KR. A Case for Hydrogen Sulfide Metabolism as an Oxygen Sensing Mechanism. Antioxidants (Basel) 2021; 10:antiox10111650. [PMID: 34829521 PMCID: PMC8615108 DOI: 10.3390/antiox10111650] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/08/2021] [Accepted: 10/13/2021] [Indexed: 12/30/2022] Open
Abstract
The ability to detect oxygen availability is a ubiquitous attribute of aerobic organisms. However, the mechanism(s) that transduce oxygen concentration or availability into appropriate physiological responses is less clear and often controversial. This review will make the case for oxygen-dependent metabolism of hydrogen sulfide (H2S) and polysulfides, collectively referred to as reactive sulfur species (RSS) as a physiologically relevant O2 sensing mechanism. This hypothesis is based on observations that H2S and RSS metabolism is inversely correlated with O2 tension, exogenous H2S elicits physiological responses identical to those produced by hypoxia, factors that affect H2S production or catabolism also affect tissue responses to hypoxia, and that RSS efficiently regulate downstream effectors of the hypoxic response in a manner consistent with a decrease in O2. H2S-mediated O2 sensing is then compared to the more generally accepted reactive oxygen species (ROS) mediated O2 sensing mechanism and a number of reasons are offered to resolve some of the confusion between the two.
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Affiliation(s)
- Kenneth R Olson
- Department of Physiology, Indiana University School of Medicine-South Bend, South Bend, IN 46617, USA
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3
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Iturriaga R, Alcayaga J, Chapleau MW, Somers VK. Carotid body chemoreceptors: physiology, pathology, and implications for health and disease. Physiol Rev 2021; 101:1177-1235. [PMID: 33570461 PMCID: PMC8526340 DOI: 10.1152/physrev.00039.2019] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The carotid body (CB) is the main peripheral chemoreceptor for arterial respiratory gases O2 and CO2 and pH, eliciting reflex ventilatory, cardiovascular, and humoral responses to maintain homeostasis. This review examines the fundamental biology underlying CB chemoreceptor function, its contribution to integrated physiological responses, and its role in maintaining health and potentiating disease. Emphasis is placed on 1) transduction mechanisms in chemoreceptor (type I) cells, highlighting the role played by the hypoxic inhibition of O2-dependent K+ channels and mitochondrial oxidative metabolism, and their modification by intracellular molecules and other ion channels; 2) synaptic mechanisms linking type I cells and petrosal nerve terminals, focusing on the role played by the main proposed transmitters and modulatory gases, and the participation of glial cells in regulation of the chemosensory process; 3) integrated reflex responses to CB activation, emphasizing that the responses differ dramatically depending on the nature of the physiological, pathological, or environmental challenges, and the interactions of the chemoreceptor reflex with other reflexes in optimizing oxygen delivery to the tissues; and 4) the contribution of enhanced CB chemosensory discharge to autonomic and cardiorespiratory pathophysiology in obstructive sleep apnea, congestive heart failure, resistant hypertension, and metabolic diseases and how modulation of enhanced CB reactivity in disease conditions may attenuate pathophysiology.
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Affiliation(s)
- Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile, and Centro de Excelencia en Biomedicina de Magallanes, Universidad de Magallanes, Punta Arenas, Chile
| | - Julio Alcayaga
- Laboratorio de Fisiología Celular, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Mark W Chapleau
- Department of Internal Medicine, University of Iowa and Department of Veterans Affairs Medical Center, Iowa City, Iowa
| | - Virend K Somers
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota
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4
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Bernardini A, Wolf A, Brockmeier U, Riffkin H, Metzen E, Acker-Palmer A, Fandrey J, Acker H. Carotid body type I cells engage flavoprotein and Pin1 for oxygen sensing. Am J Physiol Cell Physiol 2020; 318:C719-C731. [PMID: 31967857 DOI: 10.1152/ajpcell.00320.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Carotid body (CB) type I cells sense the blood Po2 and generate a nervous signal for stimulating ventilation and circulation when blood oxygen levels decline. Three oxygen-sensing enzyme complexes may be used for this purpose: 1) mitochondrial electron transport chain metabolism, 2) heme oxygenase 2 (HO-2)-generating CO, and/or 3) an NAD(P)H oxidase (NOX). We hypothesize that intracellular redox changes are the link between the sensor and nervous signals. To test this hypothesis type I cell autofluorescence of flavoproteins (Fp) and NAD(P)H within the mouse CB ex vivo was recorded as Fp/(Fp+NAD(P)H) redox ratio. CB type I cell redox ratio transiently declined with the onset of hypoxia. Upon reoxygenation, CB type I cells showed a significantly increased redox ratio. As a control organ, the non-oxygen-sensing sympathetic superior cervical ganglion (SCG) showed a continuously reduced redox ratio upon hypoxia. CN-, diphenyleneiodonium, or reactive oxygen species influenced chemoreceptor discharge (CND) with subsequent loss of O2 sensitivity and inhibited hypoxic Fp reduction only in the CB but not in SCG Fp, indicating a specific role of Fp in the oxygen-sensing process. Hypoxia-induced changes in CB type I cell redox ratio affected peptidyl prolyl isomerase Pin1, which is believed to colocalize with the NADPH oxidase subunit p47phox in the cell membrane to trigger the opening of potassium channels. We postulate that hypoxia-induced changes in the Fp-mediated redox ratio of the CB regulate the Pin1/p47phox tandem to alter type I cell potassium channels and therewith CND.
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Affiliation(s)
- André Bernardini
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Alexandra Wolf
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Ulf Brockmeier
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Helena Riffkin
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Eric Metzen
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Amparo Acker-Palmer
- Institute for Cell Biology and Neuroscience, Goethe University, Frankfurt, Germany
| | - Joachim Fandrey
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
| | - Helmut Acker
- Institute of Physiology, University of Duisburg-Essen, Essen, Germany
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5
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Hydroxycobalamin Reveals the Involvement of Hydrogen Sulfide in the Hypoxic Responses of Rat Carotid Body Chemoreceptor Cells. Antioxidants (Basel) 2019; 8:antiox8030062. [PMID: 30871199 PMCID: PMC6466535 DOI: 10.3390/antiox8030062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 03/01/2019] [Accepted: 03/09/2019] [Indexed: 12/28/2022] Open
Abstract
Carotid body (CB) chemoreceptor cells sense arterial blood PO2, generating a neurosecretory response proportional to the intensity of hypoxia. Hydrogen sulfide (H2S) is a physiological gaseous messenger that is proposed to act as an oxygen sensor in CBs, although this concept remains controversial. In the present study we have used the H2S scavenger and vitamin B12 analog hydroxycobalamin (Cbl) as a new tool to investigate the involvement of endogenous H2S in CB oxygen sensing. We observed that the slow-release sulfide donor GYY4137 elicited catecholamine release from isolated whole carotid bodies, and that Cbl prevented this response. Cbl also abolished the rise in [Ca2+]i evoked by 50 µM NaHS in enzymatically dispersed CB glomus cells. Moreover, Cbl markedly inhibited the catecholamine release and [Ca2+]i rise caused by hypoxia in isolated CBs and dispersed glomus cells, respectively, whereas it did not alter these responses when they were evoked by high [K+]e. The L-type Ca2+ channel blocker nifedipine slightly inhibited the rise in CB chemoreceptor cells [Ca2+]i elicited by sulfide, whilst causing a somewhat larger attenuation of the hypoxia-induced Ca2+ signal. We conclude that Cbl is a useful and specific tool for studying the function of H2S in cells. Based on its effects on the CB chemoreceptor cells we propose that endogenous H2S is an amplifier of the hypoxic transduction cascade which acts mainly by stimulating non-L-type Ca2+ channels.
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6
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Peng YJ, Makarenko VV, Gridina A, Chupikova I, Zhang X, Kumar GK, Fox AP, Prabhakar NR. H 2S mediates carotid body response to hypoxia but not anoxia. Respir Physiol Neurobiol 2019; 259:75-85. [PMID: 30086385 PMCID: PMC6252114 DOI: 10.1016/j.resp.2018.08.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 07/16/2018] [Accepted: 08/03/2018] [Indexed: 02/05/2023]
Abstract
The role of cystathionine-γ-lyase (CSE) derived H2S in the hypoxic and anoxic responses of the carotid body (CB) were examined. Experiments were performed on Sprague-Dawley rats, wild type and CSE knockout mice on C57BL/6 J background. Hypoxia (pO2 = 37 ± 3 mmHg) increased the CB sensory nerve activity and elevated H2S levels in rats. In contrast, anoxia (pO2 = 5 ± 4 mmHg) produced only a modest CB sensory excitation with no change in H2S levels. DL-propargylglycine (DL-PAG), a blocker of CSE, inhibited hypoxia but not anoxia-evoked CB sensory excitation and [Ca2+]i elevation of glomus cells. The inhibitory effects of DL-PAG on hypoxia were seen: a) when it is dissolved in saline but not in dimethyl sulfoxide (DMSO), and b) in glomus cells cultured for18 h but not in cells either soon after isolation or after prolonged culturing (72 h) requiring 1-3 h of incubation. On the other hand, anoxia-induced [Ca2+]i responses of glomus cell were blocked by high concentration of DL-PAG (300μM) either alone or in combination with aminooxyacetic acid (AOAA; 300μM) with a decreased cell viability. Anoxia produced a weak CB sensory excitation and robust [Ca2+]i elevation in glomus cells of both wild-type and CSE null mice. As compared to wild-type, CSE null mice exhibited impaired CB chemo reflex as evidenced by attenuated efferent phrenic nerve responses to brief hyperoxia (Dejours test), and hypoxia. Inhalation of 100% N2 (anoxia) depressed breathing in both CSE null and wild-type mice. These observations demonstrate that a) hypoxia and anoxia are not analogous stimuli for studying CB physiology and b) CSE-derived H2S contributes to CB response to hypoxia but not to that of anoxia.
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Affiliation(s)
- Ying-Jie Peng
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA.
| | - Vladislav V Makarenko
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
| | - Anna Gridina
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
| | - Irina Chupikova
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
| | - Xiuli Zhang
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
| | - Ganesh K Kumar
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
| | - Aaron P Fox
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
| | - Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology of O2Sensing, University of Chicago, Chicago, IL, 60637, USA
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7
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Prabhakar NR, Peng YJ, Nanduri J. Recent advances in understanding the physiology of hypoxic sensing by the carotid body. F1000Res 2018; 7. [PMID: 30631432 PMCID: PMC6284772 DOI: 10.12688/f1000research.16247.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/29/2018] [Indexed: 01/05/2023] Open
Abstract
Hypoxia resulting from reduced oxygen (O
2) levels in the arterial blood is sensed by the carotid body (CB) and triggers reflex stimulation of breathing and blood pressure to maintain homeostasis. Studies in the past five years provided novel insights into the roles of heme oxygenase-2 (HO-2), a carbon monoxide (CO)-producing enzyme, and NADH dehydrogenase Fe-S protein 2, a subunit of the mitochondrial complex I, in hypoxic sensing by the CB. HO-2 is expressed in type I cells, the primary O2-sensing cells of the CB, and binds to O
2 with low affinity. O
2-dependent CO production from HO-2 mediates hypoxic response of the CB by regulating H
2S generation. Mice lacking NDUFS2 show that complex I-generated reactive oxygen species acting on K
+ channels confer type I cell response to hypoxia. Whether these signaling pathways operate synergistically or independently remains to be studied.
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Affiliation(s)
- Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, The University of Chicago, Chicago, IL, 60637, USA
| | - Ying-Jie Peng
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, The University of Chicago, Chicago, IL, 60637, USA
| | - Jayasri Nanduri
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, The University of Chicago, Chicago, IL, 60637, USA
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8
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Rakoczy RJ, Wyatt CN. Acute oxygen sensing by the carotid body: a rattlebag of molecular mechanisms. J Physiol 2018; 596:2969-2976. [PMID: 29214644 PMCID: PMC6068253 DOI: 10.1113/jp274351] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 11/27/2017] [Indexed: 12/14/2022] Open
Abstract
The molecular underpinnings of the oxygen sensitivity of the carotid body Type I cells are becoming better defined as research begins to identify potential interactions between previously separate theories. Nevertheless, the field of oxygen chemoreception still presents the general observer with a bewildering array of potential signalling pathways by which a fall in oxygen levels might initiate Type I cell activation. The purpose of this brief review is to address five of the current oxygen sensing hypotheses: the lactate-Olfr 78 hypothesis of oxygen chemotransduction; the role mitochondrial ATP and metabolism may have in chemotransduction; the AMP-activated protein kinase hypothesis and its current role in oxygen sensing by the carotid body; reactive oxygen species as key transducers in the oxygen sensing cascade; and the mechanisms by which H2 S, reactive oxygen species and haem oxygenase may integrate to provide a rapid oxygen sensing transduction system. Over the previous 15 years several lines of research into acute hypoxic chemotransduction mechanisms have focused on the integration of mitochondrial and membrane signalling. This review places an emphasis on the subplasmalemmal-mitochondrial microenvironment in Type I cells and how theories of acute oxygen sensing are increasingly dependent on functional interaction within this microenvironment.
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Affiliation(s)
- Ryan J. Rakoczy
- Department of Neuroscience, Cell Biology, and PhysiologyWright State University3640 Colonel Glenn HwyDaytonOH45435USA
| | - Christopher N. Wyatt
- Department of Neuroscience, Cell Biology, and PhysiologyWright State University3640 Colonel Glenn HwyDaytonOH45435USA
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Holmes AP, Ray CJ, Coney AM, Kumar P. Is Carotid Body Physiological O 2 Sensitivity Determined by a Unique Mitochondrial Phenotype? Front Physiol 2018; 9:562. [PMID: 29867584 PMCID: PMC5964187 DOI: 10.3389/fphys.2018.00562] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/30/2018] [Indexed: 12/12/2022] Open
Abstract
The mammalian carotid body (CB) is the primary arterial chemoreceptor that responds to acute hypoxia, initiating systemic protective reflex responses that act to maintain O2 delivery to the brain and vital organs. The CB is unique in that it is stimulated at O2 levels above those that begin to impact on the metabolism of most other cell types. Whilst a large proportion of the CB chemotransduction cascade is well defined, the identity of the O2 sensor remains highly controversial. This short review evaluates whether the mitochondria can adequately function as acute O2 sensors in the CB. We consider the similarities between mitochondrial poisons and hypoxic stimuli in their ability to activate the CB chemotransduction cascade and initiate rapid cardiorespiratory reflexes. We evaluate whether the mitochondria are required for the CB to respond to hypoxia. We also discuss if the CB mitochondria are different to those located in other non-O2 sensitive cells, and what might cause them to have an unusually low O2 binding affinity. In particular we look at the potential roles of competitive inhibitors of mitochondrial complex IV such as nitric oxide in establishing mitochondrial and CB O2-sensitivity. Finally, we discuss novel signaling mechanisms proposed to take place within and downstream of mitochondria that link mitochondrial metabolism with cellular depolarization.
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Affiliation(s)
| | | | | | - Prem Kumar
- Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
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10
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Reactive oxygen radicals and gaseous transmitters in carotid body activation by intermittent hypoxia. Cell Tissue Res 2018; 372:427-431. [PMID: 29470646 DOI: 10.1007/s00441-018-2807-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 01/23/2018] [Indexed: 01/16/2023]
Abstract
Sleep apnea is a prevalent respiratory disease characterized by periodic cessation of breathing during sleep causing intermittent hypoxia (IH). Sleep apnea patients and rodents exposed to IH exhibit elevated sympathetic nerve activity and hypertension. A heightened carotid body (CB) chemoreflex has been implicated in causing autonomic abnormalities in IH-treated rodents and in sleep apnea patients. The purpose of this article is to review the emerging evidence showing that interactions between reactive oxygen species (ROS) and gaseous transmitters as a mechanism cause hyperactive CB by IH. Rodents treated with IH exhibit markedly elevated ROS in the CB, which is due to transcriptional upregulation of pro-oxidant enzymes by hypoxia-inducible factor (HIF)-1 and insufficient transcriptional regulation of anti-oxidant enzymes by HIF-2. ROS, in turn, increases cystathionine γ-lyase (CSE)-dependent H2S production in the CB. Blockade of H2S synthesis prevents IH-evoked CB activation. However, the effects of ROS on H2S production are not due to direct effects on CSE enzyme activity but rather due to inactivation of heme oxygenase-2 (HO-2), a carbon monoxide (CO) producing enzyme. CO inhibits H2S production through inactivation of CSE by PKG-dependent phosphorylation. During IH, reduced CO production resulting from inactivation of HO-2 by ROS releases the inhibition of CO on CSE thereby increasing H2S. Inhibiting H2S synthesis prevented IH-evoked sympathetic activation and hypertension.
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11
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Prabhakar NR. Carotid body chemoreflex: a driver of autonomic abnormalities in sleep apnoea. Exp Physiol 2018; 101:975-85. [PMID: 27474260 DOI: 10.1113/ep085624] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 05/13/2016] [Indexed: 12/14/2022]
Abstract
What is the topic of this review? This article presents emerging evidence for heightened carotid body chemoreflex activity as a major driver of sympathetic activation and hypertension in sleep apnoea patients. What advances does it heighlight? This article discusses the recent advances on cellular, molecular and epigenetic mechanisms underlying the exaggerated chemoreflex in experimental models of sleep apnoea. The carotid bodies are the principal peripheral chemoreceptors for detecting changes in arterial blood oxygen concentration, and the resulting chemoreflex is a potent regulator of the sympathetic tone, blood pressure and breathing. Sleep apnoea is a disease of the respiratory system that affects several million adult humans. Apnoeas occur during sleep, often as a result of obstruction of the upper airway (obstructive sleep apnoea) or because of defective respiratory rhythm generation by the CNS (central sleep apnoea). Patients with sleep apnoea exhibit several co-morbidities, with the most notable among them being heightened sympathetic nerve activity and hypertension. Emerging evidence suggests that intermittent hypoxia resulting from periodic apnoea stimulates the carotid body, and the ensuing chemoreflex mediates the increased sympathetic tone and hypertension in sleep apnoea patients. Rodent models of intermittent hypoxia that simulate the O2 saturation profiles encountered during sleep apnoea have provided important insights into the cellular and molecular mechanisms underlying the heightened carotid body chemoreflex. This article describes how intermittent hypoxia affects the carotid body function and discusses the cellular, molecular and epigenetic mechanisms underlying the exaggerated chemoreflex.
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Affiliation(s)
- Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, Biological Sciences Division, University of Chicago, Chicago, IL, USA
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12
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Wang J, Hogan JO, Wang R, White C, Kim D. Role of cystathionine-γ-lyase in hypoxia-induced changes in TASK activity, intracellular [Ca 2+] and ventilation in mice. Respir Physiol Neurobiol 2017; 246:98-106. [PMID: 28851593 DOI: 10.1016/j.resp.2017.08.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 08/09/2017] [Accepted: 08/15/2017] [Indexed: 10/19/2022]
Abstract
Cystathionine-γ-lyase (CSE) is a multifunctional enzyme, and hydrogen sulfide (H2S) is one of its products. CSE and H2S have recently been proposed to be critical signaling molecules in hypoxia-induced excitation of carotid body (CB) glomus cells and the chemosensory response. Because the role of H2S in arterial chemoreception is still debated, we further examined the role of CSE by studying the effects of hypoxia on TASK K+ channel activity, cell depolarization, [Ca2+]i and ventilation using CSE+/+ and CSE-/- mice. As predicted, hypoxia reduced TASK activity and depolarized glomus cells isolated from CSE+/+ mice. These effects of hypoxia were not significantly altered in glomus cells from CSE-/- mice. Basal [Ca2+]i and hypoxia-induced elevation of [Ca2+] were also not significantly different in glomus cells from CSE+/+ and CSE-/- mice. In whole-body plethysmography, hypoxia (10%O2) increased minute ventilation in both CSE+/+ and CSE-/- mice equally well, and no significant differences were found in either males or females when adjusted by body weight. Together, these results show that deletion of the CSE gene has no effects on hypoxia-induced changes in TASK, cell depolarization, [Ca2+]i and ventilation, and therefore do not support the idea that CSE/H2S signaling is important for CB chemoreceptor activity in mice.
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Affiliation(s)
- Jiaju Wang
- Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, United States
| | - James O Hogan
- Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, United States
| | - Rui Wang
- Cardiovascular and Metabolic Research Unit, Laurentian University, Sudbury, Canada
| | - Carl White
- Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, United States
| | - Donghee Kim
- Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, United States.
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Wang J, Hogan JO, Kim D. Voltage- and receptor-mediated activation of a non-selective cation channel in rat carotid body glomus cells. Respir Physiol Neurobiol 2016; 237:13-21. [PMID: 28013061 DOI: 10.1016/j.resp.2016.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/16/2016] [Accepted: 12/08/2016] [Indexed: 10/20/2022]
Abstract
A recent study showed that hypoxia activates a Ca2+-sensitive, Na+-permeable non-selective cation channel (NSC) in carotid body glomus cells. We studied the effects of mitochondrial inhibitors that increase Ca2+ influx via Ca2+ channel (Cav), and receptor agonists that release Ca2+ from endoplasmic reticulum (ER) on NSC. Mitochondrial inhibitors (NaCN, FCCP, H2S, NO) elevated [Ca2+]i and activated NSC. Angiotensin II and acetylcholine that elevate [Ca2+]i via the Gq-IP3 pathway activated NSC. However, endothelin-1 (Gq) and 5-HT (Gq) showed little or no effect on [Ca2+]i and did not activate NSC. Adenosine (Gs) caused a weak rise in [Ca2+]i but did not activate NSC. Dopamine (Gs) and γ-aminobytyric acid (Gi) were ineffective in raising [Ca2+]i and failed to activate NSC. Store-operated Ca2+ entry (SOCE) produced by depletion of Ca2+ stores with cyclopiazonic acid activated NSC. Our results show that Ca2+ entry via Cav, ER Ca2+ release and SOCE can activate NSC. Thus, NSC contributes to both voltage- and receptor-mediated excitation of glomus cells.
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Affiliation(s)
- Jiaju Wang
- Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, USA
| | - James O Hogan
- Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, USA
| | - Donghee Kim
- Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, USA.
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14
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López-Barneo J, González-Rodríguez P, Gao L, Fernández-Agüera MC, Pardal R, Ortega-Sáenz P. Oxygen sensing by the carotid body: mechanisms and role in adaptation to hypoxia. Am J Physiol Cell Physiol 2016; 310:C629-42. [PMID: 26764048 DOI: 10.1152/ajpcell.00265.2015] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Oxygen (O2) is fundamental for cell and whole-body homeostasis. Our understanding of the adaptive processes that take place in response to a lack of O2(hypoxia) has progressed significantly in recent years. The carotid body (CB) is the main arterial chemoreceptor that mediates the acute cardiorespiratory reflexes (hyperventilation and sympathetic activation) triggered by hypoxia. The CB is composed of clusters of cells (glomeruli) in close contact with blood vessels and nerve fibers. Glomus cells, the O2-sensitive elements in the CB, are neuron-like cells that contain O2-sensitive K(+)channels, which are inhibited by hypoxia. This leads to cell depolarization, Ca(2+)entry, and the release of transmitters to activate sensory fibers terminating at the respiratory center. The mechanism whereby O2modulates K(+)channels has remained elusive, although several appealing hypotheses have been postulated. Recent data suggest that mitochondria complex I signaling to membrane K(+)channels plays a fundamental role in acute O2sensing. CB activation during exposure to low Po2is also necessary for acclimatization to chronic hypoxia. CB growth during sustained hypoxia depends on the activation of a resident population of stem cells, which are also activated by transmitters released from the O2-sensitive glomus cells. These advances should foster further studies on the role of CB dysfunction in the pathogenesis of highly prevalent human diseases.
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Affiliation(s)
- José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Patricia González-Rodríguez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Lin Gao
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - M Carmen Fernández-Agüera
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Ricardo Pardal
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío, CSIC, Universidad de Sevilla, Seville, Spain; Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Seville, Spain; and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
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An emerging role for gasotransmitters in the control of breathing and ionic regulation in fish. J Comp Physiol B 2015; 186:145-59. [DOI: 10.1007/s00360-015-0949-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 11/04/2015] [Accepted: 11/25/2015] [Indexed: 10/22/2022]
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