1
|
Caballero-Eraso C, Colinas O, Sobrino V, González-Montelongo R, Cabeza JM, Gao L, Pardal R, López-Barneo J, Ortega-Sáenz P. Rearrangement of cell types in the rat carotid body neurogenic niche induced by chronic intermittent hypoxia. J Physiol 2023; 601:1017-1036. [PMID: 36647759 DOI: 10.1113/jp283897] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
The carotid body (CB) is a prototypical acute oxygen (O2 )-sensing organ that mediates reflex hyperventilation and increased cardiac output in response to hypoxaemia. CB overactivation, secondary to the repeated stimulation produced by the recurrent episodes of intermittent hypoxia, is believed to contribute to the pathogenesis of sympathetic hyperactivity present in sleep apnoea patients. Although CB functional plasticity induced by chronic intermittent hypoxia (CIH) has been demonstrated, the underlying mechanisms are not fully elucidated. Here, we show that CIH induces a small increase in CB volume and rearrangement of cell types in the CB, characterized by a mobilization of immature quiescent neuroblasts, which enter a process of differentiation into mature, O2 -sensing and neuron-like, chemoreceptor glomus cells. Prospective isolation of individual cell classes has allowed us to show that maturation of CB neuroblasts is paralleled by an upregulation in the expression of specific glomus cell genes involved in acute O2 -sensing. CIH enhances mitochondrial responsiveness to hypoxia in maturing neuroblasts as well as in glomus cells. These data provide novel perspectives on the pathogenesis of CB-mediated sympathetic overflow that may lead to the development of new pharmacological strategies of potential applicability in sleep apnoea patients. KEY POINTS: Obstructive sleep apnoea is a frequent condition in the human population that predisposes to severe cardiovascular and metabolic alterations. Activation of the carotid body, the main arterial oxygen-sensing chemoreceptor, by repeated episodes of hypoxaemia induces exacerbation of the carotid body-mediated chemoreflex and contributes to sympathetic overflow characteristic of sleep apnoea patients. In rats, chronic intermittent hypoxaemia induces fast neurogenesis in the carotid body with rapid activation of neuroblasts, which enter a process of proliferation and maturation into O2 -sensing chemoreceptor glomus cells. Maturing carotid body neuroblasts and glomus cells exposed to chronic intermittent hypoxia upregulate genes involved in acute O2 sensing and enhance mitochondrial responsiveness to hypoxia. These findings provide novel perspectives on the pathogenesis of carotid body-mediated sympathetic hyperactivation. Pharmacological modulation of carotid body fast neurogenesis could help to ameliorate the deleterious effects of chronic intermittent hypoxaemia in sleep apnoea patients.
Collapse
Affiliation(s)
- Candela Caballero-Eraso
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Unidad Médico Quirúrgica de Enfermedades Respiratorias, Hospital Universitario Virgen del Rocío/IBIS, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Olaia Colinas
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
| | - Verónica Sobrino
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Rafaela González-Montelongo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - José María Cabeza
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain
| | - Lin Gao
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, 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, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
| | - José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
| | - Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
| |
Collapse
|
2
|
Abstract
The carotid body (CB) is a bilateral arterial chemoreceptor located in the carotid artery bifurcation with an essential role in cardiorespiratory homeostasis. It is composed of highly perfused cell clusters, or glomeruli, innervated by sensory fibers. Glomus cells, the most abundant in each glomerulus, are neuron-like multimodal sensory elements able to detect and integrate changes in several physical and chemical parameters of the blood, in particular O2 tension, CO2 and pH, as well as glucose, lactate, or blood flow. Activation of glomus cells (e.g., during hypoxia or hypercapnia) stimulates the afferent fibers which impinge on brainstem neurons to elicit rapid compensatory responses (hyperventilation and sympathetic activation). This chapter presents an updated view of the structural organization of the CB and the mechanisms underlying the chemosensory responses of glomus cells, with special emphasis on the molecular processes responsible for acute O2 sensing. The properties of the glomus cell-sensory fiber synapse as well as the organization of CB output are discussed. The chapter includes the description of recently discovered CB stem cells and progenitor cells, and their role in CB growth during acclimatization to hypoxemia. Finally, the participation of the CB in the mechanisms of disease is briefly discussed.
Collapse
Affiliation(s)
- José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Sevilla, Seville, Spain; Biomedical Research Center for Neurodegenerative Diseases (CIBERNED), Madrid, Spain.
| |
Collapse
|
3
|
Ortega-Sáenz P, Moreno-Domínguez A, Gao L, López-Barneo J. Molecular Mechanisms of Acute Oxygen Sensing by Arterial Chemoreceptor Cells. Role of Hif2α. Front Physiol 2020; 11:614893. [PMID: 33329066 PMCID: PMC7719705 DOI: 10.3389/fphys.2020.614893] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/03/2020] [Indexed: 01/28/2023] Open
Abstract
Carotid body glomus cells are multimodal arterial chemoreceptors able to sense and integrate changes in several physical and chemical parameters in the blood. These cells are also essential for O2 homeostasis. Glomus cells are prototypical peripheral O2 sensors necessary to detect hypoxemia and to elicit rapid compensatory responses (hyperventilation and sympathetic activation). The mechanisms underlying acute O2 sensing by glomus cells have been elusive. Using a combination of mouse genetics and single-cell optical and electrophysiological techniques, it has recently been shown that activation of glomus cells by hypoxia relies on the generation of mitochondrial signals (NADH and reactive oxygen species), which modulate membrane ion channels to induce depolarization, Ca2+ influx, and transmitter release. The special sensitivity of glomus cell mitochondria to changes in O2 tension is due to Hif2α-dependent expression of several atypical mitochondrial subunits, which are responsible for an accelerated oxidative metabolism and the strict dependence of mitochondrial complex IV activity on O2 availability. A mitochondrial-to-membrane signaling model of acute O2 sensing has been proposed, which explains existing data and provides a solid foundation for future experimental tests. This model has also unraveled new molecular targets for pharmacological modulation of carotid body activity potentially relevant in the treatment of highly prevalent medical conditions.
Collapse
Affiliation(s)
- Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Alejandro Moreno-Domínguez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain
| | - Lin Gao
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Seville, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - 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
| |
Collapse
|
4
|
Neurotransmitter Modulation of Carotid Body Germinal Niche. Int J Mol Sci 2020; 21:ijms21218231. [PMID: 33153142 PMCID: PMC7662800 DOI: 10.3390/ijms21218231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 10/30/2020] [Accepted: 11/01/2020] [Indexed: 12/25/2022] Open
Abstract
The carotid body (CB), a neural-crest-derived organ and the main arterial chemoreceptor in mammals, is composed of clusters of cells called glomeruli. Each glomerulus contains neuron-like, O2-sensing glomus cells, which are innervated by sensory fibers of the petrosal ganglion and are located in close contact with a dense network of fenestrated capillaries. In response to hypoxia, glomus cells release transmitters to activate afferent fibers impinging on the respiratory and autonomic centers to induce hyperventilation and sympathetic activation. Glomus cells are embraced by interdigitating processes of sustentacular, glia-like, type II cells. The CB has an extraordinary structural plasticity, unusual for a neural tissue, as it can grow several folds its size in subjects exposed to sustained hypoxia (as for example in high altitude dwellers or in patients with cardiopulmonary diseases). CB growth in hypoxia is mainly due to the generation of new glomeruli and blood vessels. In recent years it has been shown that the adult CB contains a collection of quiescent multipotent stem cells, as well as immature progenitors committed to the neurogenic or the angiogenic lineages. Herein, we review the main properties of the different cell types in the CB germinal niche. We also summarize experimental data suggesting that O2-sensitive glomus cells are the master regulators of CB plasticity. Upon exposure to hypoxia, neurotransmitters and neuromodulators released by glomus cells act as paracrine signals that induce proliferation and differentiation of multipotent stem cells and progenitors, thus causing CB hypertrophy and an increased sensory output. Pharmacological modulation of glomus cell activity might constitute a useful clinical tool to fight pathologies associated with exaggerated sympathetic outflow due to CB overactivation.
Collapse
|
5
|
Abstract
The carotid body (CB) is an arterial chemoreceptor organ located in the carotid bifurcation and has a well-recognized role in cardiorespiratory regulation. The CB contains neurosecretory sensory cells (glomus cells), which release transmitters in response to hypoxia, hypercapnia, and acidemia to activate afferent sensory fibers terminating in the respiratory and autonomic brainstem centers. Knowledge of the physiology of the CB has progressed enormously in recent years. Herein we review advances concerning the organization and function of the cellular elements of the CB, with emphasis on the molecular mechanisms of acute oxygen sensing by glomus cells. We introduce the modern view of the CB as a multimodal integrated metabolic sensor and describe the properties of the CB stem cell niche, which support CB growth during acclimatization to chronic hypoxia. Finally, we discuss the increasing medical relevance of CB dysfunction and its potential impact on the mechanisms of disease.
Collapse
Affiliation(s)
- Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla 41013, Spain; , .,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sevilla 41013, Spain
| | - José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla 41013, Spain; , .,Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Sevilla 41013, Spain
| |
Collapse
|
6
|
Mosqueira M, Iturriaga R. Chronic hypoxia changes gene expression profile of primary rat carotid body cells: consequences on the expression of NOS isoforms and ET-1 receptors. Physiol Genomics 2019; 51:109-124. [DOI: 10.1152/physiolgenomics.00114.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Sustained chronic hypoxia (CH) produces morphological and functional changes in the carotid body (CB). Nitric oxide (NO) and endothelin-1 (ET-1) play a major role as modulators of the CB oxygen chemosensory process. To characterize the effects of CH related to normoxia (Nx) on gene expression, particularly on ET-1 and NO pathways, primary cultures of rat CB cells were exposed to 7 days of CH. Total RNA was extracted, and cDNA-32P was synthesized and hybridized with 1,185 genes printed on a nylon membrane Atlas cDNA Expression Array. Out of 324 differentially expressed genes, 184 genes were upregulated, while 140 genes were downregulated. The cluster annotation and protein network analyses showed that both NO and ET-1 signaling pathways were significantly enriched and key elements of each pathway were differentially expressed. Thus, we assessed the effect of CH at the protein level of nitric oxide synthase (NOS) isoforms and ET-1 receptors. CH induced an increase in the expression of endothelial NOS, inducible NOS, and ETB. During CH, the administration of SNAP, a NO donor, upregulated ETB. Treatment with Tezosentan (ET-1 receptor blocker) during CH upregulated all three NOS isoforms, while the NOS blocker L-NAME induced upregulation of iNOS and ETB and downregulated the protein levels of ETA. These results show that CH for 7 days changed the cultured cell CB gene expression profile, the NO and ET-1 signaling pathways were highly enriched, and these two signaling pathways interfered with the protein expression of each other.
Collapse
Affiliation(s)
- Matías Mosqueira
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago Chile
- Cardio-Ventilatory Muscle Physiology Laboratory, Institute of Physiology and Pathophysiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago Chile
| |
Collapse
|
7
|
Sobrino V, Annese V, Navarro-Guerrero E, Platero-Luengo A, Pardal R. The carotid body: a physiologically relevant germinal niche in the adult peripheral nervous system. Cell Mol Life Sci 2019; 76:1027-1039. [PMID: 30498994 PMCID: PMC11105339 DOI: 10.1007/s00018-018-2975-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/05/2018] [Accepted: 11/22/2018] [Indexed: 12/26/2022]
Abstract
Oxygen constitutes a vital element for the survival of every single cell in multicellular aerobic organisms like mammals. A complex homeostatic oxygen-sensing system has evolved in these organisms, including detectors and effectors, to guarantee a proper supply of the element to every cell. The carotid body represents the most important peripheral arterial chemoreceptor organ in mammals and informs about hypoxemic situations to the effectors at the brainstem cardiorespiratory centers. To optimize organismal adaptation to maintained hypoxemic situations, the carotid body has evolved containing a niche of adult tissue-specific stem cells with the capacity to differentiate into both neuronal and vascular cell types in response to hypoxia. These neurogenic and angiogenic processes are finely regulated by the niche and by hypoxia itself. Our recent data on the cellular and molecular mechanisms underlying the functioning of this niche might help to comprehend a variety of different diseases coursing with carotid body failure, and might also improve our capacity to use these stem cells for the treatment of neurological disease. Herein, we review those data about the recent characterization of the carotid body niche, focusing on the study of the phenotype and behavior of multipotent stem cells within the organ, comparing them with other well-documented neural stem cells within the adult nervous system.
Collapse
Affiliation(s)
- Verónica Sobrino
- Instituto de Biomedicina de Sevilla (IBiS), Laboratory 103, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Dpto. de Fisiología Médica y Biofísica, Avda, Manuel Siurot, s/n., 41013, Sevilla, Spain
| | - Valentina Annese
- Instituto de Biomedicina de Sevilla (IBiS), Laboratory 103, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Dpto. de Fisiología Médica y Biofísica, Avda, Manuel Siurot, s/n., 41013, Sevilla, Spain
| | - Elena Navarro-Guerrero
- Instituto de Biomedicina de Sevilla (IBiS), Laboratory 103, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Dpto. de Fisiología Médica y Biofísica, Avda, Manuel Siurot, s/n., 41013, Sevilla, Spain
| | - Aida Platero-Luengo
- Instituto de Biomedicina de Sevilla (IBiS), Laboratory 103, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Dpto. de Fisiología Médica y Biofísica, Avda, Manuel Siurot, s/n., 41013, Sevilla, Spain
| | - Ricardo Pardal
- Instituto de Biomedicina de Sevilla (IBiS), Laboratory 103, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Dpto. de Fisiología Médica y Biofísica, Avda, Manuel Siurot, s/n., 41013, Sevilla, Spain.
| |
Collapse
|
8
|
Pulgar-Sepúlveda R, Varas R, Iturriaga R, Del Rio R, Ortiz FC. Carotid Body Type-I Cells Under Chronic Sustained Hypoxia: Focus on Metabolism and Membrane Excitability. Front Physiol 2018; 9:1282. [PMID: 30283346 PMCID: PMC6157308 DOI: 10.3389/fphys.2018.01282] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/24/2018] [Indexed: 12/23/2022] Open
Abstract
Chronic sustained hypoxia (CSH) evokes ventilatory acclimatization characterized by a progressive hyperventilation due to a potentiation of the carotid body (CB) chemosensory response to hypoxia. The transduction of the hypoxic stimulus in the CB begins with the inhibition of K+ currents in the chemosensory (type-I) cells, which in turn leads to membrane depolarization, Ca2+ entry and the subsequent release of one- or more-excitatory neurotransmitters. Several studies have shown that CSH modifies both the level of transmitters and chemoreceptor cell metabolism within the CB. Most of these studies have been focused on the role played by such putative transmitters and modulators of CB chemoreception, but less is known about the effect of CSH on metabolism and membrane excitability of type-I cells. In this mini-review, we will examine the effects of CSH on the ion channels activity and excitability of type-I cell, with a particular focus on the effects of CSH on the TASK-like background K+ channel. We propose that changes on TASK-like channel activity induced by CSH may contribute to explain the potentiation of CB chemosensory activity.
Collapse
Affiliation(s)
- Raúl Pulgar-Sepúlveda
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Rodrigo Varas
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
- Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Talca, Chile
| | - Rodrigo Iturriaga
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Envejecimiento y Regeneración, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes, Universidad de Magallanes, Punta Arenas, Chile
| | - Fernando C. Ortiz
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| |
Collapse
|
9
|
López-Barneo J. Oxygen sensing and stem cell activation in the hypoxic carotid body. Cell Tissue Res 2018; 372:417-425. [PMID: 29368257 DOI: 10.1007/s00441-017-2783-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 12/22/2017] [Indexed: 12/15/2022]
Abstract
The carotid body (CB) is the major arterial chemoreceptor responsible for the detection of acute decreases in O2 tension (hypoxia) in arterial blood that trigger hyperventilation and sympathetic activation. The CB contains O2-sensitive glomus (chief) cells, which respond to hypoxia with the release of transmitters to activate sensory nerve fibers impinging upon the brain respiratory and autonomic centers. During exposure to sustained hypoxia (for weeks or months), the CB grows several-fold in size, a response associated with acclimatization to high altitude or to medical conditions presenting hypoxemia. Here, I briefly present recent advances on the mechanisms underlying glomus cell sensitivity to hypoxia, in particular the role of mitochondrial complex I in acute oxygen sensing. I also summarize the properties of adult CB stem cells and of glomus cell-stem cell synapses, which contribute to CB hypertrophy in chronic hypoxia. A note on the relationship between hypoxic CB growth and tumorigenesis is included. Finally, the medical implications of CB pathophysiology are discussed.
Collapse
Affiliation(s)
- José López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Avenida Manuel Siurot s/n, 41013, Seville, Spain. .,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain. .,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
| |
Collapse
|
10
|
Sobrino V, González-Rodríguez P, Annese V, López-Barneo J, Pardal R. Fast neurogenesis from carotid body quiescent neuroblasts accelerates adaptation to hypoxia. EMBO Rep 2018; 19:embr.201744598. [PMID: 29335248 DOI: 10.15252/embr.201744598] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 11/30/2017] [Accepted: 12/13/2017] [Indexed: 01/01/2023] Open
Abstract
Unlike other neural peripheral organs, the adult carotid body (CB) has a remarkable structural plasticity, as it grows during acclimatization to hypoxia. The CB contains neural stem cells that can differentiate into oxygen-sensitive glomus cells. However, an extended view is that, unlike other catecholaminergic cells of the same lineage (sympathetic neurons or chromaffin cells), glomus cells can divide and thus contribute to CB hypertrophy. Here, we show that O2-sensitive mature glomus cells are post-mitotic. However, we describe an unexpected population of pre-differentiated, immature neuroblasts that express catecholaminergic markers and contain voltage-dependent ion channels, but are unresponsive to hypoxia. Neuroblasts are quiescent in normoxic conditions, but rapidly proliferate and differentiate into mature glomus cells during hypoxia. This unprecedented "fast neurogenesis" is stimulated by ATP and acetylcholine released from mature glomus cells. CB neuroblasts, which may have evolved to facilitate acclimatization to hypoxia, could contribute to the CB oversensitivity observed in highly prevalent human diseases.
Collapse
Affiliation(s)
- Verónica Sobrino
- 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
| | - 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
| | - Valentina Annese
- 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
| | - 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.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Seville, 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
| |
Collapse
|
11
|
Dos Santos E, Sacramento JF, Melo BF, Conde SV. Carotid Body Dysfunction in Diet-Induced Insulin Resistance Is Associated with Alterations in Its Morphology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1071:103-108. [DOI: 10.1007/978-3-319-91137-3_13] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
12
|
Annese V, Navarro-Guerrero E, Rodríguez-Prieto I, Pardal R. Physiological Plasticity of Neural-Crest-Derived Stem Cells in the Adult Mammalian Carotid Body. Cell Rep 2017; 19:471-478. [PMID: 28423311 PMCID: PMC5409929 DOI: 10.1016/j.celrep.2017.03.065] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 02/21/2017] [Accepted: 03/27/2017] [Indexed: 12/22/2022] Open
Abstract
Adult stem cell plasticity, or the ability of somatic stem cells to cross boundaries and differentiate into unrelated cell types, has been a matter of debate in the last decade. Neural-crest-derived stem cells (NCSCs) display a remarkable plasticity during development. Whether adult populations of NCSCs retain this plasticity is largely unknown. Herein, we describe that neural-crest-derived adult carotid body stem cells (CBSCs) are able to undergo endothelial differentiation in addition to their reported role in neurogenesis, contributing to both neurogenic and angiogenic processes taking place in the organ during acclimatization to hypoxia. Moreover, CBSC conversion into vascular cell types is hypoxia inducible factor (HIF) dependent and sensitive to hypoxia-released vascular cytokines such as erythropoietin. Our data highlight a remarkable physiological plasticity in an adult population of tissue-specific stem cells and could have impact on the use of these cells for cell therapy. Adult carotid body stem cells display multipotency during organ adaptation to hypoxia Neural-crest-derived stem cells contribute to angiogenesis in the adult carotid body Endothelial differentiation from carotid body stem cells is HIF2α and EPO dependent
Collapse
Affiliation(s)
- Valentina Annese
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville 41013, Spain.
| | - Elena Navarro-Guerrero
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville 41013, Spain
| | - Ismael Rodríguez-Prieto
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville 41013, Spain
| | - Ricardo Pardal
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Seville 41013, Spain.
| |
Collapse
|
13
|
Oxygen-sensing by arterial chemoreceptors: Mechanisms and medical translation. Mol Aspects Med 2016; 47-48:90-108. [DOI: 10.1016/j.mam.2015.12.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 12/01/2015] [Indexed: 12/30/2022]
|
14
|
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: 89] [Impact Index Per Article: 11.1] [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.
Collapse
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
| |
Collapse
|
15
|
Weiss JW, Tamisier R, Liu Y. Sympathoexcitation and arterial hypertension associated with obstructive sleep apnea and cyclic intermittent hypoxia. J Appl Physiol (1985) 2015; 119:1449-54. [PMID: 26251511 DOI: 10.1152/japplphysiol.00315.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/03/2015] [Indexed: 12/15/2022] Open
Abstract
Obstructive sleep apnea (OSA) is characterized by repetitive episodes of upper airway obstruction during sleep. These obstructive episodes are characterized by cyclic intermittent hypoxia (CIH), by sleep fragmentation, and by hemodynamic instability, and they result in sustained sympathoexcitation and elevated arterial pressure that persist during waking, after restoration of normoxia. Early studies established that 1) CIH, rather than sleep disruption, accounts for the increase in arterial pressure; 2) the increase in arterial pressure is a consequence of the sympathoactivation; and 3) arterial hypertension after CIH exposure requires an intact peripheral chemoreflex. More recently, however, evidence has accumulated that sympathoactivation and hypertension after CIH are also dependent on altered central sympathoregulation. Furthermore, although many molecular pathways are activated in both the carotid chemoreceptor and in the central nervous system by CIH exposure, two specific neuromodulators-endothelin-1 and angiotensin II-appear to play crucial roles in mediating the sympathetic and hemodynamic response to intermittent hypoxia.
Collapse
Affiliation(s)
- J Woodrow Weiss
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts;
| | - Renaud Tamisier
- Sleep Laboratory and EFCR, Pôle Rééducation et Physiologie, University Hospital, HP2 Laboratory (Hypoxia: Pathophysiology) INSERM ERI 17, EA 3745 Joseph Fourier University, Grenoble, France; and
| | - Yuzhen Liu
- First Afflicted Hospital of Xinxiang Medical University, Xinxiang, Henan, China
| |
Collapse
|
16
|
Ortega-Sáenz P, Villadiego J, Pardal R, Toledo-Aral JJ, López-Barneo J. Neurotrophic Properties, Chemosensory Responses and Neurogenic Niche of the Human Carotid Body. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 860:139-52. [PMID: 26303476 DOI: 10.1007/978-3-319-18440-1_16] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The carotid body (CB) is a polymodal chemoreceptor that triggers the hyperventilatory response to hypoxia necessary for the maintenance of O(2) homeostasis essential for the survival of organs such as the brain or heart. Glomus cells, the sensory elements in the CB, are also sensitive to hypercapnia, acidosis and, although less generally accepted, hypoglycemia. Current knowledge on CB function is mainly based on studies performed on lower mammals, but the information on the human CB is scant. Here we describe the structure, neurotrophic properties, and cellular responses to hypoxia and hypoglycemia of CBs dissected from human cadavers. The adult CB parenchyma contains clusters of chemosensitive glomus (type I) and sustentacular (type II) cells as well as nestin-positive progenitor cells. This organ also expresses high levels of the dopaminotrophic glial cell line-derived neurotrophic factor (GDNF). GDNF production and the number of progenitor and glomus cells were preserved in the CBs of human subjects of advanced age. As reported for other mammalian species, glomus cells responded to hypoxia by external Ca(2+)-dependent increase of cytosolic [Ca(2+)] and quantal catecholamine release. Human glomus cells are also responsive to hypoglycemia and together the two stimuli, hypoxia and hypoglycemia, can potentiate each other's effects. The chemo-sensory responses of glomus cells are also preserved at an advanced age. Interestingly, a neurogenic niche similar to that recently described in rodents is also preserved in the adult human CB. These new data on the cellular and molecular physiology of the CB pave the way for future pathophysiological studies involving this organ in humans.
Collapse
Affiliation(s)
- Patricia Ortega-Sáenz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Avenida Manuel Siurot s/n, 41013, Seville, Spain
| | | | | | | | | |
Collapse
|
17
|
Platero-Luengo A, González-Granero S, Durán R, Díaz-Castro B, Piruat JI, García-Verdugo JM, Pardal R, López-Barneo J. An O2-sensitive glomus cell-stem cell synapse induces carotid body growth in chronic hypoxia. Cell 2014; 156:291-303. [PMID: 24439383 DOI: 10.1016/j.cell.2013.12.013] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 10/07/2013] [Accepted: 11/11/2013] [Indexed: 01/28/2023]
Abstract
Neural stem cells (NSCs) exist in germinal centers of the adult brain and in the carotid body (CB), an oxygen-sensing organ that grows under chronic hypoxemia. How stem cell lineage differentiation into mature glomus cells is coupled with changes in physiological demand is poorly understood. Here, we show that hypoxia does not affect CB NSC proliferation directly. Rather, mature glomus cells expressing endothelin-1, the O2-sensing elements in the CB that secrete neurotransmitters in response to hypoxia, establish abundant synaptic-like contacts with stem cells, which express endothelin receptors, and instruct their growth. Inhibition of glomus cell transmitter release or their selective destruction markedly diminishes CB cell growth during hypoxia, showing that CB NSCs are under the direct "synaptic" control of the mature O2-sensitive cells. Thus, glomus cells not only acutely activate the respiratory center but also induce NSC-dependent CB hypertrophy necessary for acclimatization to chronic hypoxemia.
Collapse
Affiliation(s)
- Aida Platero-Luengo
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Seville, Spain
| | - Susana González-Granero
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universidad de Valencia, 46071 Valencia, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
| | - Rocío Durán
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Seville, Spain
| | - Blanca Díaz-Castro
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Seville, Spain
| | - José I Piruat
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Seville, Spain
| | - José Manuel García-Verdugo
- Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Universidad de Valencia, 46071 Valencia, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain
| | - Ricardo Pardal
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Seville, Spain.
| | - José López-Barneo
- Departamento de Fisiología Médica y Biofísica, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Seville, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), 28031 Madrid, Spain.
| |
Collapse
|
18
|
Hussain I, Husain Q, Baredes S, Eloy JA, Jyung RW, Liu JK. Molecular genetics of paragangliomas of the skull base and head and neck region: implications for medical and surgical management. J Neurosurg 2014; 120:321-30. [DOI: 10.3171/2013.10.jns13659] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Paragangliomas are rare, slow-growing tumors that frequently arise in the head and neck, with the carotid bodies and temporal bone of the skull base being the most common sites. These neoplasms are histologically similar to pheochromocytomas that form in the adrenal medulla and are divided into sympathetic and parasympathetic subtypes based on functionality. Skull base and head and neck region paragangliomas (SHN-PGs) are almost always derived from parasympathetic tissue and rarely secrete catecholamines. However, they can cause significant morbidity by mass effect on various cranial nerves and major blood vessels. While surgery for SHN-PG can be curative, postoperative deficits and recurrences make these lesions challenging to manage. Multiple familial syndromes predisposing individuals to development of paragangliomas have been identified, all involving mutations in the succinate dehydrogenase complex of mitochondria. Mutations in this enzyme lead to a state of “pseudohypoxia” that upregulates various angiogenic, survival, and proliferation factors. Moreover, familial paraganglioma syndromes are among the rare inherited diseases in which genomic imprinting occurs. Recent advances in gene arrays and transcriptome/exome sequencing have identified an alternate mutation in sporadic SHN-PG, which regulates proto-oncogenic pathways independent of pseudohypoxia-induced factors. Collectively these findings demonstrate that paragangliomas of the skull base and head and neck region have a distinct genetic signature from sympathetic-based paragangliomas occurring below the neck, such as pheochromocytomas. Paragangliomas serve as a unique model of primarily surgically treated neoplasms whose future will be altered by the elucidation of their genomic complexities. In this review, the authors present an analysis of the molecular genetics of SHN-PG and provide future directions in patient care and the development of novel therapies.
Collapse
Affiliation(s)
| | | | - Soly Baredes
- 2Otolaryngology–Head and Neck Surgery, and
- 3Center for Skull Base and Pituitary Surgery, Neurological Institute of New Jersey, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Jean Anderson Eloy
- 1Departments of Neurological Surgery and
- 2Otolaryngology–Head and Neck Surgery, and
- 3Center for Skull Base and Pituitary Surgery, Neurological Institute of New Jersey, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Robert W. Jyung
- 2Otolaryngology–Head and Neck Surgery, and
- 3Center for Skull Base and Pituitary Surgery, Neurological Institute of New Jersey, Rutgers New Jersey Medical School, Newark, New Jersey
| | - James K. Liu
- 1Departments of Neurological Surgery and
- 2Otolaryngology–Head and Neck Surgery, and
- 3Center for Skull Base and Pituitary Surgery, Neurological Institute of New Jersey, Rutgers New Jersey Medical School, Newark, New Jersey
| |
Collapse
|
19
|
Donovan LM, Liu Y, Weiss JW. Effect of endothelin antagonism on apnea frequency following chronic intermittent hypoxia. Respir Physiol Neurobiol 2014; 194:6-8. [PMID: 24468467 DOI: 10.1016/j.resp.2014.01.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 01/17/2014] [Accepted: 01/20/2014] [Indexed: 10/25/2022]
Abstract
Chronic hypoxia increases the hypoxic ventilatory response (HVR). Augmented HVR contributes to central apneas seen in heart failure and complex sleep apnea. Endothelin receptor (ETR) antagonism decreases carotid body afferent activity following chronic intermittent hypoxia (CIH). We speculated ETR antagonism would reduce HVR and apneas following CIH. HVR and apneas were measured after exposure to CIH and room air sham (SHAM). ETR blocker Ambrisentan was administered via the chow of CIH-exposed animals from days 1 to 12 of CIH (CIH/AMB). A separate crossover group was exposed to CIH and fed normal chow (placebo) days 1-6, and Ambrisentan days 7-12 (CIH/PLA-AMB). SHAM and CIH/PLA animals were fed placebo days 1-12. The CIH/AMB and CIH/PLA-AMB rats had reduced HVR compared to CIH/PLA, similar HVR compared to sham exposed animals, and reduced apnea frequency compared to CIH/PLA animals. The reduced HVR and post-hypoxic apneas resulting from Ambrisentan administration suggests ETR antagonists may have utility in reducing central apneas following CIH.
Collapse
Affiliation(s)
- Lucas M Donovan
- Beth Israel Deaconess Medical Center, Division of Pulmonary Critical Care, and Sleep Medicine, Boston, MA, United States.
| | - Yuzhen Liu
- Beth Israel Deaconess Medical Center, Division of Pulmonary Critical Care, and Sleep Medicine, Boston, MA, United States
| | - J Woodrow Weiss
- Beth Israel Deaconess Medical Center, Division of Pulmonary Critical Care, and Sleep Medicine, Boston, MA, United States
| |
Collapse
|
20
|
Liu X, He L, Dinger B, Stensaas L, Fidone S. Sustained exposure to cytokines and hypoxia enhances excitability of oxygen-sensitive type I cells in rat carotid body: correlation with the expression of HIF-1α protein and adrenomedullin. High Alt Med Biol 2013; 14:53-60. [PMID: 23537261 DOI: 10.1089/ham.2012.1054] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Recent studies in our laboratory demonstrated that chronic hypoxia (CH) induces a localized inflammatory response in rat carotid body that is characterized by macrophage invasion and increased expression of inflammatory cytokines. Moreover, CH-induced increased hypoxic sensitivity is blocked by concurrent treatment with the common anti-inflammatory drugs, ibuprofen and dexamethasone. The present study examines the hypothesis that selected cytokines enhance the excitability of oxygen-sensitive type I cells in the carotid body, and that downstream effects of cytokines involve upregulation of the transcription factor, hypoxia inducible factor-1α (HIF-1α). Cultured type I cells were exposed for 24 h to hypoxia and/or a cocktail of cytokines consisting of interleukin-1β, interleukin-6, and tumor necrosis factor-α. Subsequent evaluation of hypoxia-evoked intracellular Ca(2+)-responses showed that previous exposure to cytokines plus hypoxia resulted in a 110% (p<0.001) increase in cell excitability, whereas exposure to cytokines or hypoxia alone elicited smaller increases of 22% (not significant) and 35% (p<0.01), respectively. These changes were correlated with increased immunostaining for HIF-1α in similarly treated type I cells, where exposure to cytokines plus hypoxia promoted the nuclear translocation of the transcription factor. Moreover, treatment with cytokines and/or hypoxia elevated the expression of the HIF-1-regulated gene, adrenomedullin. These in vitro results are supported by studies which show that elevated type I cell sensitivity following in vivo CH is blocked by concurrent treatment with ibuprofen. The data suggest that CH-induced adaptation in arterial chemoreceptors may in part be mediated by cytokine/hypoxia-induced upregulation of HIF-1α, and consequent enhanced expression of specific hypoxia-sensitive genes in type I cells.
Collapse
Affiliation(s)
- Xuemei Liu
- Department of Physiology, University of Utah School of Medicine, Salt Lake City, Utah 84108, USA
| | | | | | | | | |
Collapse
|
21
|
Ortega-Sáenz P, Pardal R, Levitsky K, Villadiego J, Muñoz-Manchado AB, Durán R, Bonilla-Henao V, Arias-Mayenco I, Sobrino V, Ordóñez A, Oliver M, Toledo-Aral JJ, López-Barneo J. Cellular properties and chemosensory responses of the human carotid body. J Physiol 2013; 591:6157-73. [PMID: 24167224 DOI: 10.1113/jphysiol.2013.263657] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The carotid body (CB) is the major peripheral arterial chemoreceptor in mammals that mediates the acute hyperventilatory response to hypoxia. The CB grows in response to sustained hypoxia and also participates in acclimatisation to chronic hypoxaemia. Knowledge of CB physiology at the cellular level has increased considerably in recent times thanks to studies performed on lower mammals, and rodents in particular. However, the functional characteristics of human CB cells remain practically unknown. Herein, we use tissue slices or enzymatically dispersed cells to determine the characteristics of human CB cells. The adult human CB parenchyma contains clusters of chemosensitive glomus (type I) and sustentacular (type II) cells as well as nestin-positive progenitor cells. This organ also expresses high levels of the dopaminotrophic glial cell line-derived neurotrophic factor (GDNF). We found that GDNF production and the number of progenitor and glomus cells were preserved in the CBs of human subjects of advanced age. Moreover, glomus cells exhibited voltage-dependent Na(+), Ca(2+) and K(+) currents that were qualitatively similar to those reported in lower mammals. These cells responded to hypoxia with an external Ca(2+)-dependent increase of cytosolic Ca(2+) and quantal catecholamine secretion, as reported for other mammalian species. Interestingly, human glomus cells are also responsive to hypoglycaemia and together these two stimuli can potentiate each other's effects. The chemosensory responses of glomus cells are also preserved at an advanced age. These new data on the cellular and molecular physiology of the CB pave the way for future pathophysiological studies involving this organ in humans.
Collapse
Affiliation(s)
- Patricia Ortega-Sáenz
- J. López-Barneo: Instituto de Biomedicina de Sevilla (IBiS), Campus Hospital Universitario Virgen del Rocío, Avenida Manuel Siurot s/n, 41013 Seville, Spain.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Liu X, He L, Dinger B, Stensaas L, Fidone S. Effect of endothelin receptor antagonist bosentan on chronic hypoxia-induced inflammation and chemoafferent neuron adaptation in rat carotid body. High Alt Med Biol 2013; 13:209-16. [PMID: 22994521 DOI: 10.1089/ham.2012.1011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Chronic hypoxia (CH) induces an inflammatory response in rat carotid body that is characterized by immune cell invasion and the expression of pro-inflammatory cytokines. In the present study, we have investigated the role of type-A endothelin (ET-A) receptors in the development of CH-induced inflammation. After 7 days of CH (380 Torr), double-label immunofluorescence studies demonstrated elevated levels of ET-A receptor and tyrosine hydroxylase (TH) in O(2)-sensitive type I cells. Following CH, ET-A receptors were also expressed on resident and invasive CD45+ immune cells distributed in tissue surrounding chemosensory cell lobules. Immnofluorescence and quantitative PCR studies showed that concurrent treatment with the ET-A/B receptor antagonist, bosentan (200 mg/kg/day), blocked CH-induced ED-1+ macrophage invasion and the upregulation of cytokines, including interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor α (TNFα), and monocyte chemoattractant protein-1 (MCP-1). Moreover, bosentan treatment blocked the CH-induced increases in expression of acid-sensitive ion channels (ASICs) in chemoafferent neurons in the petrosal ganglion (PG). Our findings are consistent with the hypothesis that CH-induced inflammation involves the upregulation and release of ET-1 from type I cells. ET-1 may act in an autocrine/paracrine mechanism via ET-A receptors on chemosensory type I cells and immune cells to promote an inflammatory response.
Collapse
Affiliation(s)
- Xuemei Liu
- Department of Physiology, University of Utah School of Medicine, Salt Lake City, Utah 84108, USA
| | | | | | | | | |
Collapse
|
23
|
Prabhakar NR, Semenza GL. Adaptive and maladaptive cardiorespiratory responses to continuous and intermittent hypoxia mediated by hypoxia-inducible factors 1 and 2. Physiol Rev 2012; 92:967-1003. [PMID: 22811423 DOI: 10.1152/physrev.00030.2011] [Citation(s) in RCA: 429] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Hypoxia is a fundamental stimulus that impacts cells, tissues, organs, and physiological systems. The discovery of hypoxia-inducible factor-1 (HIF-1) and subsequent identification of other members of the HIF family of transcriptional activators has provided insight into the molecular underpinnings of oxygen homeostasis. This review focuses on the mechanisms of HIF activation and their roles in physiological and pathophysiological responses to hypoxia, with an emphasis on the cardiorespiratory systems. HIFs are heterodimers comprised of an O(2)-regulated HIF-1α or HIF-2α subunit and a constitutively expressed HIF-1β subunit. Induction of HIF activity under conditions of reduced O(2) availability requires stabilization of HIF-1α and HIF-2α due to reduced prolyl hydroxylation, dimerization with HIF-1β, and interaction with coactivators due to decreased asparaginyl hydroxylation. Stimuli other than hypoxia, such as nitric oxide and reactive oxygen species, can also activate HIFs. HIF-1 and HIF-2 are essential for acute O(2) sensing by the carotid body, and their coordinated transcriptional activation is critical for physiological adaptations to chronic hypoxia including erythropoiesis, vascularization, metabolic reprogramming, and ventilatory acclimatization. In contrast, intermittent hypoxia, which occurs in association with sleep-disordered breathing, results in an imbalance between HIF-1α and HIF-2α that causes oxidative stress, leading to cardiorespiratory pathology.
Collapse
Affiliation(s)
- Nanduri R Prabhakar
- Institute for Integrative Physiology and Center for Systems Biology of O2 Sensing, Biological Sciences Division, University of Chicago, Chicago, Illinois, USA.
| | | |
Collapse
|
24
|
Conde SV, Ribeiro MJ, Obeso A, Rigual R, Monteiro EC, Gonzalez C. Chronic caffeine intake in adult rat inhibits carotid body sensitization produced by chronic sustained hypoxia but maintains intact chemoreflex output. Mol Pharmacol 2012; 82:1056-65. [PMID: 22930709 DOI: 10.1124/mol.112.081216] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Sustained hypoxia produces a carotid body (CB) sensitization, known as acclimatization, which leads to an increase in carotid sinus nerve (CSN) activity and ensuing hyperventilation greater than expected from the prevailing partial pressure of oxygen. Whether sustained hypoxia is physiological (high altitude) or pathological (lung disease), acclimatization has a homeostatic implication because it tends to minimize hypoxia. Caffeine, the most commonly ingested psychoactive drug and a nonselective adenosine receptor antagonist, alters CB function and ventilatory responses when administered acutely. Our aim was to investigate the effect of chronic caffeine intake on CB function and acclimatization using four groups of rats: normoxic, caffeine-treated normoxic, chronically hypoxic (12% O₂, 15 days), and caffeine-treated chronically hypoxic rats. Caffeine was administered in drinking water (1 mg/ml). Caffeine ameliorated ventilatory responses to acute hypoxia in normoxic animals without altering the output of the CB (CSN neural activity). Caffeine-treated chronically hypoxic rats exhibited a decrease in the CSN response to acute hypoxia tests but maintained ventilation compared with chronically hypoxic animals. The findings related to CSN neural activity combined with the ventilatory responses indicate that caffeine alters central integration of the CB input to increase the gain of the chemoreflex and that caffeine abolishes CB acclimatization. The putative mechanisms involved in sensitization and its loss were investigated: expression of adenosine receptors in CB (A(2B)) was down-regulated and that in petrosal ganglion (A(2A)) was up-regulated in caffeine-treated chronically hypoxic rats; both adenosine and dopamine release from CB chemoreceptor cells was increased in chronic hypoxia and in caffeine-treated chronic hypoxia groups.
Collapse
Affiliation(s)
- Silvia V Conde
- Department of Pharmacology, Faculty of Medical Sciences, New University of Lisbon, Portugal.
| | | | | | | | | | | |
Collapse
|
25
|
Abstract
The discovery of the sensory nature of the carotid body dates back to the beginning of the 20th century. Following these seminal discoveries, research into carotid body mechanisms moved forward progressively through the 20th century, with many descriptions of the ultrastructure of the organ and stimulus-response measurements at the level of the whole organ. The later part of 20th century witnessed the first descriptions of the cellular responses and electrophysiology of isolated and cultured type I and type II cells, and there now exist a number of testable hypotheses of chemotransduction. The goal of this article is to provide a comprehensive review of current concepts on sensory transduction and transmission of the hypoxic stimulus at the carotid body with an emphasis on integrating cellular mechanisms with the whole organ responses and highlighting the gaps or discrepancies in our knowledge. It is increasingly evident that in addition to hypoxia, the carotid body responds to a wide variety of blood-borne stimuli, including reduced glucose and immune-related cytokines and we therefore also consider the evidence for a polymodal function of the carotid body and its implications. It is clear that the sensory function of the carotid body exhibits considerable plasticity in response to the chronic perturbations in environmental O2 that is associated with many physiological and pathological conditions. The mechanisms and consequences of carotid body plasticity in health and disease are discussed in the final sections of this article.
Collapse
Affiliation(s)
- Prem Kumar
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, The University of Birmingham, Birmingham, United Kingdom.
| | | |
Collapse
|
26
|
Del Rio R, Muñoz C, Arias P, Court FA, Moya EA, Iturriaga R. Chronic intermittent hypoxia-induced vascular enlargement and VEGF upregulation in the rat carotid body is not prevented by antioxidant treatment. Am J Physiol Lung Cell Mol Physiol 2011; 301:L702-11. [PMID: 21821731 DOI: 10.1152/ajplung.00128.2011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Chronic intermittent hypoxia (CIH), a characteristic of sleep obstructive apnea, enhances carotid body (CB) chemosensory responses to hypoxia, but its consequences on CB vascular area and VEGF expression are unknown. Accordingly, we studied the effect of CIH on CB volume, glomus cell numbers, blood vessel diameter and number, and VEGF immunoreactivity (VEGF-ir) in male Sprague-Dawley rats exposed to 5% O(2), 12 times/h for 8 h or sham condition for 21 days. We found that CIH did not modify the CB volume or the number of glomus cells but increased VEGF-ir and enlarged the vascular area by increasing the size of the blood vessels, whereas the number of the vessels was unchanged. Because oxidative stress plays an essential role in the CIH-induced carotid chemosensory potentiation, we tested whether antioxidant treatment with ascorbic acid may impede the vascular enlargement and the VEGF upregulation. Ascorbic acid, which prevents the CB chemosensory potentiation, failed to impede the vascular enlargement and the increased VEGF-ir. Thus present results suggest that the CB vascular enlargement induced by CIH is a direct effect of intermittent hypoxia and not secondary to the oxidative stress. Accordingly, the subsequent capillary changes may be secondary to the mechanisms involved in the neural chemosensory plasticity induced by intermittent hypoxia.
Collapse
Affiliation(s)
- Rodrigo Del Rio
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | | | | | | | | | | |
Collapse
|
27
|
Del Rio R, Moya EA, Iturriaga R. Differential expression of pro-inflammatory cytokines, endothelin-1 and nitric oxide synthases in the rat carotid body exposed to intermittent hypoxia. Brain Res 2011; 1395:74-85. [PMID: 21555119 DOI: 10.1016/j.brainres.2011.04.028] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 03/30/2011] [Accepted: 04/15/2011] [Indexed: 12/30/2022]
Abstract
The enhanced carotid body (CB) chemosensory response to hypoxia induced by chronic intermittent hypoxia (CIH) has been attributed to oxidative stress, which is expected to increase the expression of chemosensory modulators including chemoexcitatory pro-inflammatory cytokines in the CB. Accordingly, we studied the time-course of the changes in the immunohistological expression of TNF-α, IL-1β, IL-6, ET-1, iNOS, eNOS and 3-nitrotyrosine in the CB, along with the progression of enhanced CB chemosensory responses to acute hypoxia in male Sprague-Dawley rats exposed to CIH (5%O₂, 12 times/h per 8h) for 7, 14 and 21 days. Exposure to CIH for 7 days resulted in a sustained potentiation of CB chemosensory responses to acute hypoxia, which persisted until 21 days of CIH. The chemosensory potentiation was paralleled by an increased 3-nitrotyrosine expression in the CB. On the contrary, CIH produced a transient 2-fold increase of ET-1 immunoreactivity at 7 days, a decrease in eNOS immunoreactivity, and a delayed but progressive increase of TNF-α, IL-1β and iNOS immunoreactivity, which was not associated with changes in systemic plasma levels or immune cell invasion within the CB. Thus, present results suggest that the local expression of chemosensory modulators and pro-inflammatory cytokines in the CB may have different temporal contribution to the CB chemosensory potentiation induced by CIH.
Collapse
Affiliation(s)
- Rodrigo Del Rio
- Laboratorio de Neurobiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | | | | |
Collapse
|
28
|
Prabhakar NR, Kumar GK, Nanduri J. Intermittent hypoxia augments acute hypoxic sensing via HIF-mediated ROS. Respir Physiol Neurobiol 2010; 174:230-4. [PMID: 20804864 DOI: 10.1016/j.resp.2010.08.022] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Revised: 08/23/2010] [Accepted: 08/24/2010] [Indexed: 11/17/2022]
Abstract
Carotid bodies and neonatal adrenal medullary chromaffin cells (AMC) respond rapidly to acute hypoxia before compromising cellular functions. Responses to acute hypoxia are dynamically altered by chronic perturbations in arterial blood O2 levels resulting from breathing disorders. Sleep disordered breathing with recurrent apneas cause periodic decreases in arterial blood O2 or intermittent hypoxia (IH). Recent studies suggest that reactive oxygen species (ROS) mediate cellular adaptations to prolonged hypoxia. In this article we discuss the evidence for ROS in mediating exaggerated carotid body and AMC responses to acute hypoxia by IH and the underlying cellular and molecular mechanisms. IH increases ROS levels, and anti-oxidants prevent IH-induced augmented responses of the carotid body and AMC to hypoxia. The enhanced hypoxic sensitivity by IH involves ROS-dependent recruitment of transmitters/modulators in the carotid body and Ca2+ signaling mechanisms in AMC. Mechanisms by which IH elevates ROS include activation of NADPH oxidases, inhibition of mitochondrial complex I activity and down-regulation of anti-oxidant enzymes. Transcriptional regulation of pro- and anti-oxidant enzymes by hypoxia-inducible factors 1 and 2 appears to be a major molecular mechanism regulating ROS generation by IH.
Collapse
Affiliation(s)
- Nanduri R Prabhakar
- Center for Systems Biology of O2 Sensing, Department of Medicine, University of Chicago, IL 60637, USA.
| | | | | |
Collapse
|
29
|
Teppema LJ, Dahan A. The Ventilatory Response to Hypoxia in Mammals: Mechanisms, Measurement, and Analysis. Physiol Rev 2010; 90:675-754. [DOI: 10.1152/physrev.00012.2009] [Citation(s) in RCA: 257] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The respiratory response to hypoxia in mammals develops from an inhibition of breathing movements in utero into a sustained increase in ventilation in the adult. This ventilatory response to hypoxia (HVR) in mammals is the subject of this review. The period immediately after birth contains a critical time window in which environmental factors can cause long-term changes in the structural and functional properties of the respiratory system, resulting in an altered HVR phenotype. Both neonatal chronic and chronic intermittent hypoxia, but also chronic hyperoxia, can induce such plastic changes, the nature of which depends on the time pattern and duration of the exposure (acute or chronic, episodic or not, etc.). At adult age, exposure to chronic hypoxic paradigms induces adjustments in the HVR that seem reversible when the respiratory system is fully matured. These changes are orchestrated by transcription factors of which hypoxia-inducible factor 1 has been identified as the master regulator. We discuss the mechanisms underlying the HVR and its adaptations to chronic changes in ambient oxygen concentration, with emphasis on the carotid bodies that contain oxygen sensors and initiate the response, and on the contribution of central neurotransmitters and brain stem regions. We also briefly summarize the techniques used in small animals and in humans to measure the HVR and discuss the specific difficulties encountered in its measurement and analysis.
Collapse
Affiliation(s)
- Luc J. Teppema
- Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Albert Dahan
- Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands
| |
Collapse
|
30
|
He L, Liu X, Chen J, Dinger B, Stensaas L, Fidone S. Modulation of chronic hypoxia-induced chemoreceptor hypersensitivity by NADPH oxidase subunits in rat carotid body. J Appl Physiol (1985) 2010; 108:1304-10. [PMID: 20185631 DOI: 10.1152/japplphysiol.00766.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies in our laboratory established that reactive oxygen species (ROS) generated by NADPH oxidase (NOX) facilitate the open state of a subset of K+ channels in oxygen-sensitive type I cells of the carotid body. Thus pharmacological inhibition of NOX or deletion of a NOX gene resulted in enhanced chemoreceptor sensitivity to hypoxia. The present study tests the hypothesis that chronic hypoxia (CH)-induced hypersensitivity of chemoreceptors is modulated by increased NOX activity and elevated levels of ROS. Measurements of dihydroethidium fluorescence in carotid body tissue slices showed that increased ROS production following CH (14 days, 380 Torr) was blocked by the specific NOX inhibitor 4-(2-amino-ethyl)benzenesulfonyl fluoride (AEBSF, 3 microM). Consistent with these findings, in normal carotid body AEBSF elicited a small increase in the chemoreceptor nerve discharge evoked by an acute hypoxic challenge, whereas after 9 days of CH the effect of the NOX inhibitor was some threefold larger (P<0.001). Evaluation of gene expression after 7 days of CH showed increases in the isoforms NOX2 (approximately 1.5-fold) and NOX4 (approximately 3.8-fold) and also increased presence of the regulatory subunit p47phox (approximately 4.2-fold). Involvement of p47phox was further implicated in studies of isolated type I cells that demonstrated an approximately 8-fold and an approximately 11-fold increase in mRNA after 1 and 3 days, respectively, of hypoxia in vivo. These findings were confirmed in immunocytochemical studies of carotid body tissue that showed a robust increase of p47phox in type I cells after 14 days of CH. Our findings suggest that increased ROS production by NOX enzymes in type I cells dampens CH-induced hypersensitivity in carotid body chemoreceptors.
Collapse
Affiliation(s)
- L He
- Department of Physiology, University of Utah School of Medicine, 420 Chipeta Way, Suite 1700, Salt Lake City, UT 84108-6500, USA
| | | | | | | | | | | |
Collapse
|
31
|
Iturriaga R, Moya EA, Del Rio R. Carotid body potentiation induced by intermittent hypoxia: Implications for cardiorespiratory changes induced by sleep apnoea. Clin Exp Pharmacol Physiol 2009; 36:1197-204. [DOI: 10.1111/j.1440-1681.2009.05213.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
32
|
Abstract
Acclimatization to long-term hypoxia takes place at high altitude and allows gradual improvement of the ability to tolerate the hypoxic environment. An important component of this process is the hypoxic ventilatory acclimatization (HVA) that develops over several days. HVA reveals profound cellular and neurochemical re-organization occurring both in the peripheral chemoreceptors and in the central nervous system (in brainstem respiratory groups). These changes lead to an enhanced activity of peripheral chemoreceptor and re-inforce the central translation of peripheral inputs to efficient respiratory motor activity under the steady low O(2) pressure. We will review the cellular processes underlying these changes with a particular emphasis on changes of neurotransmitter function and ion channel properties in peripheral chemoreceptors, and present evidence that low O(2) level acts directly on brainstem nuclei to induce cellular changes contributing to maintain a high tonic respiratory drive under chronic hypoxia.
Collapse
Affiliation(s)
- Vincent Joseph
- Department of Pediatrics, Laval University, Centre de Recherche (D0-711), Hôpital St-François d'Assise, 10 rue de l'Espinay, Quebec, QC, G1L 3L5, Canada.
| | | |
Collapse
|
33
|
Faoro V, Boldingh S, Moreels M, Martinez S, Lamotte M, Unger P, Brimioulle S, Huez S, Naeije R. Bosentan Decreases Pulmonary Vascular Resistance and Improves Exercise Capacity in Acute Hypoxia. Chest 2009; 135:1215-1222. [DOI: 10.1378/chest.08-2222] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
|
34
|
Liu X, He L, Stensaas L, Dinger B, Fidone S. Adaptation to chronic hypoxia involves immune cell invasion and increased expression of inflammatory cytokines in rat carotid body. Am J Physiol Lung Cell Mol Physiol 2008; 296:L158-66. [PMID: 18978039 DOI: 10.1152/ajplung.90383.2008] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exposure to chronic hypoxia (CH; 3-28 days at 380 Torr) induces adaptation in mammalian carotid body such that following CH an acute hypoxic challenge elicits an abnormally large increase in carotid sinus nerve impulse activity. The current study examines the hypothesis that CH initiates an immune response in the carotid body and that chemoreceptor hyperexcitability is dependent on the expression and action of inflammatory cytokines. CH resulted in a robust invasion of ED1(+) macrophages, which peaked on day 3 of exposure. Gene expression of proinflammatory cytokines, IL-1beta, TNFalpha, and the chemokine, monocyte chemoattractant protein-1, was increased >2-fold after 1 day of hypoxia followed by a >2-fold increase in IL-6 on day 3. After 28 days of CH, IL-6 remained elevated >5-fold, whereas expression of other cytokines recovered to normal levels. Cytokine expression was not restricted to immune cells. Studies of cultured type I cells harvested following 1 day of in vivo hypoxia showed elevated transcript levels of inflammatory cytokines. In situ hybridization studies confirmed expression of IL-6 in type I cells and also showed that CH induces IL-6 expression in supporting type II cells. Concurrent treatment of CH rats with anti-inflammatory drugs (ibuprofen or dexamethasone) blocked immune cell invasion and severely reduced CH-induced cytokine expression in carotid body. Drug treatment also blocked the development of chemoreceptor hypersensitivity in CH animals. Our findings indicate that chemoreceptor adaptation involves novel neuroimmune mechanisms, which may alter the functional phenotypes of type I cells and chemoafferent neurons.
Collapse
Affiliation(s)
- X Liu
- Dept. of Physiology, Univ. of Utah School of Medicine, Salt Lake City, UT 84108-6500, USA
| | | | | | | | | |
Collapse
|
35
|
Porzionato A, Macchi V, Parenti A, De Caro R. Trophic factors in the carotid body. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 269:1-58. [PMID: 18779056 DOI: 10.1016/s1937-6448(08)01001-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The aim of the present study is to provide a review of the expression and action of trophic factors in the carotid body. In glomic type I cells, the following factors have been identified: brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor, artemin, ciliary neurotrophic factor, insulin-like growth factors-I and -II, basic fibroblast growth factor, epidermal growth factor, transforming growth factor-alpha and -beta1, interleukin-1beta and -6, tumour necrosis factor-alpha, vascular endothelial growth factor, and endothelin-1 (ET-1). Growth factor receptors in the above cells include p75LNGFR, TrkA, TrkB, RET, GDNF family receptors alpha1-3, gp130, IL-6Ralpha, EGFR, FGFR1, IL1-RI, TNF-RI, VEGFR-1 and -2, ETA and ETB receptors, and PDGFR-alpha. Differential local expression of growth factors and corresponding receptors plays a role in pre- and postnatal development of the carotid body. Their local actions contribute toward producing the morphologic and molecular changes associated with chronic hypoxia and/or hypertension, such as cellular hyperplasia, extracellular matrix expansion, changes in channel densities, and neurotransmitter patterns. Neurotrophic factor production is also considered to play a key role in the therapeutic effects of intracerebral carotid body grafts in Parkinson's disease. Future research should also focus on trophic actions on carotid body type I cells by peptide neuromodulators, which are known to be present in the carotid body and to show trophic effects on other cell populations, that is, angiotensin II, adrenomedullin, bombesin, calcitonin, calcitonin gene-related peptide, cholecystokinin, erythropoietin, galanin, opioids, pituitary adenylate cyclase-activating polypeptide, atrial natriuretic peptide, somatostatin, tachykinins, neuropeptide Y, neurotensin, and vasoactive intestinal peptide.
Collapse
Affiliation(s)
- Andrea Porzionato
- Department of Human Anatomy and Physiology, University of Padova, Padova 35127, Italy
| | | | | | | |
Collapse
|