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Wang RL, Chang RB. The Coding Logic of Interoception. Annu Rev Physiol 2024; 86:301-327. [PMID: 38061018 PMCID: PMC11103614 DOI: 10.1146/annurev-physiol-042222-023455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2024]
Abstract
Interoception, the ability to precisely and timely sense internal body signals, is critical for life. The interoceptive system monitors a large variety of mechanical, chemical, hormonal, and pathological cues using specialized organ cells, organ innervating neurons, and brain sensory neurons. It is important for maintaining body homeostasis, providing motivational drives, and regulating autonomic, cognitive, and behavioral functions. However, compared to external sensory systems, our knowledge about how diverse body signals are coded at a system level is quite limited. In this review, we focus on the unique features of interoceptive signals and the organization of the interoceptive system, with the goal of better understanding the coding logic of interoception.
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Affiliation(s)
- Ruiqi L Wang
- Department of Neuroscience and Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA;
| | - Rui B Chang
- Department of Neuroscience and Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA;
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2
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Tamir-Hostovsky L, Ivanovska J, Parajón E, Patel R, Wang H, Biouss G, Ivanovski N, Belik J, Pierro A, Montandon G, Gauda EB. Maturational effect of leptin on CO 2 chemosensitivity in newborn rats. Pediatr Res 2023; 94:971-978. [PMID: 37185965 DOI: 10.1038/s41390-023-02604-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 03/28/2023] [Accepted: 04/01/2023] [Indexed: 05/17/2023]
Abstract
BACKGROUND Leptin augments central CO2 chemosensitivity and stabilizes breathing in adults. Premature infants have unstable breathing and low leptin levels. Leptin receptors are on CO2 sensitive neurons in the Nucleus Tractus Solitarius (NTS) and locus coeruleus (LC). We hypothesized that exogenous leptin improves hypercapnic respiratory response in newborn rats by improving central CO2 chemosensitivity. METHODS In rats at postnatal day (p)4 and p21, hyperoxic and hypercapnic ventilatory responses, and pSTAT and SOCS3 protein expression in the hypothalamus, NTS and LC were measured before and after treatment with exogenous leptin (6 µg/g). RESULTS Exogenous leptin increased the hypercapnic response in p21 but not in p4 rats (P ≤ 0.001). At p4, leptin increased pSTAT expression only in the LC, and SOCS3 expression in the NTS and LC; while at p21 pSTAT and SOCS3 levels were higher in the hypothalamus, NTS, and LC (P ≤ 0.05). CONCLUSIONS We describe the developmental profile of the effect of exogenous leptin on CO2 chemosensitivity. Exogenous leptin does not augment central CO2 sensitivity during the first week of life in newborn rats. The translational implication of these findings is that low plasma leptin levels in premature infants may not be contributing to respiratory instability. IMPACT Exogenous leptin does not augment CO2 sensitivity during the first week of life in newborn rats, similar to the developmental period when feeding behavior is resistant to leptin. Exogenous leptin increases CO2 chemosensitivity in newborn rats after the 3rd week of life and upregulates the expression of pSTAT and SOC3 in the hypothalamus, NTS and LC. Low plasma leptin levels in premature infants are unlikely contributors to respiratory instability via decreased CO2 sensitivity in premature infants. Thus, it is highly unlikely that exogenous leptin would alter this response.
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Affiliation(s)
- Liran Tamir-Hostovsky
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Julijana Ivanovska
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Eleana Parajón
- Cellular and Molecular Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Rachana Patel
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Huanhuan Wang
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - George Biouss
- Division of General and Thoracic Surgery, Developmental and Stem Cell Biology Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Nikola Ivanovski
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Jaques Belik
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Agostino Pierro
- Division of General and Thoracic Surgery, Developmental and Stem Cell Biology Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Gaspard Montandon
- Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, ON, Canada
| | - Estelle B Gauda
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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3
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Lazarov NE, Atanasova DY. Mechanisms of Chemosensory Transduction in the Carotid Body. ADVANCES IN ANATOMY, EMBRYOLOGY, AND CELL BIOLOGY 2023; 237:49-62. [PMID: 37946077 DOI: 10.1007/978-3-031-44757-0_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
The mammalian carotid body (CB) is a polymodal chemoreceptor, which is activated by blood-borne stimuli, most notably hypoxia, hypercapnia and acidosis, thus ensuring an appropriate cellular response to changes in physical and chemical parameters of the blood. The glomus cells are considered the CB chemosensory cells and the initial site of chemoreceptor transduction. However, the molecular mechanisms by which they detect changes in blood chemical levels and how these changes lead to transmitter release are not yet well understood. Chemotransduction mechanisms are by far best described for oxygen and acid/carbon dioxide sensing. A few testable hypotheses have been postulated including a direct interaction of oxygen with ion channels in the glomus cells (membrane hypothesis), an indirect interface by a reversible ligand like a heme (metabolic hypothesis), or even a functional interaction between putative oxygen sensors (chemosome hypothesis) or the interaction of lactate with a highly expressed in the CB atypical olfactory receptor, Olfr78, (endocrine model). It is also suggested that sensory transduction in the CB is uniquely dependent on the actions and interactions of gaseous transmitters. Apparently, oxygen sensing does not utilize a single mechanism, and later observations have given strong support to a unified membrane model of chemotransduction.
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Affiliation(s)
- Nikolai E Lazarov
- Department of Anatomy and Histology, Faculty of Medicine, Medical University of Sofia, Sofia, Bulgaria.
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4
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Lazarov NE, Atanasova DY. Neurochemical Anatomy of the Mammalian Carotid Body. ADVANCES IN ANATOMY, EMBRYOLOGY, AND CELL BIOLOGY 2023; 237:63-103. [PMID: 37946078 DOI: 10.1007/978-3-031-44757-0_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Carotid body (CB) glomus cells in most mammals, including humans, contain a broad diversity of classical neurotransmitters, neuropeptides and gaseous signaling molecules as well as their cognate receptors. Among them, acetylcholine, adenosine triphosphate and dopamine have been proposed to be the main excitatory transmitters in the mammalian CB, although subsequently dopamine has been considered an inhibitory neuromodulator in almost all mammalian species except the rabbit. In addition, co-existence of biogenic amines and neuropeptides has been reported in the glomus cells, thus suggesting that they store and release more than one transmitter in response to natural stimuli. Furthermore, certain metabolic and transmitter-degrading enzymes are involved in the chemotransduction and chemotransmission in various mammals. However, the presence of the corresponding biosynthetic enzyme for some transmitter candidates has not been confirmed, and neuroactive substances like serotonin, gamma-aminobutyric acid and adenosine, neuropeptides including opioids, substance P and endothelin, and gaseous molecules such as nitric oxide have been shown to modulate the chemosensory process through direct actions on glomus cells and/or by producing tonic effects on CB blood vessels. It is likely that the fine balance between excitatory and inhibitory transmitters and their complex interactions might play a more important than suggested role in CB plasticity.
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Affiliation(s)
- Nikolai E Lazarov
- Department of Anatomy and Histology, Faculty of Medicine, Medical University of Sofia, Sofia, Bulgaria.
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5
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Kulej-Lyko K, Niewinski P, Tubek S, Krawczyk M, Kosmala W, Ponikowski P. Inhibition of peripheral chemoreceptors improves ventilatory efficiency during exercise in heart failure with preserved ejection fraction − a role of tonic activity and acute reflex response. Front Physiol 2022; 13:911636. [PMID: 36111161 PMCID: PMC9470150 DOI: 10.3389/fphys.2022.911636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 07/19/2022] [Indexed: 11/22/2022] Open
Abstract
Peripheral chemoreceptors (PChRs) play a significant role in maintaining adequate oxygenation in the bloodstream. PChRs functionality comprises two components: tonic activity (PChT) which regulates ventilation during normoxia and acute reflex response (peripheral chemosensitivity, PChS), which increases ventilation following a specific stimulus. There is a clear link between augmented PChS and exercise intolerance in patients with heart failure with reduced ejection fraction. It has been also shown that inhibition of PChRs leads to the improvement in exercise capacity. However, it has not been established yet: 1) whether similar mechanisms take part in heart failure with preserved ejection fraction (HFpEF) and 2) which component of PChRs functionality (PChT vs. PChS) is responsible for the benefit seen after the acute experimental blockade. To answer those questions we enrolled 12 stable patients with HFpEF. All participants underwent an assessment of PChT (attenuation of minute ventilation in response to low-dose dopamine infusion), PChS (enhancement of minute ventilation in response to hypoxia) and a symptom-limited cardiopulmonary exercise test on cycle ergometer. All tests were placebo-controlled, double-blinded and performed in a randomized order. Under resting conditions and at normoxia dopamine attenuated minute ventilation and systemic vascular resistance (p = 0.03 for both). These changes were not seen with placebo. Dopamine also decreased ventilatory and mean arterial pressure responses to hypoxia (p < 0.05 for both). Inhibition of PChRs led to a decrease in V˙E/V˙CO2 comparing to placebo (36 ± 3.6 vs. 34.3 ± 3.7, p = 0.04), with no effect on peak oxygen consumption. We found a significant relationship between PChT and the relative decrement of V˙E/V˙CO2 on dopamine comparing to placebo (R = 0.76, p = 0.005). There was a trend for correlation between PChS (on placebo) and V˙E/V˙CO2 during placebo infusion (R = 0.56, p = 0.059), but the relative improvement in V˙E/V˙CO2 was not related to the change in PChS (dopamine vs. placebo). We did not find a significant relationship between PChT and PChS. In conclusion, inhibition of PChRs in HFpEF population improves ventilatory efficiency during exercise. Increased PChS is associated with worse (higher) V˙E/V˙CO2, whereas PChT predicts an improvement in V˙E/V˙CO2 after PChRs inhibition. This results may be meaningful for patient selection in further clinical trials involving PChRs modulation.
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Affiliation(s)
- Katarzyna Kulej-Lyko
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Department of Cardiology, University Clinical Hospital, Wroclaw, Poland
- *Correspondence: Katarzyna Kulej-Lyko,
| | - Piotr Niewinski
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Department of Cardiology, University Clinical Hospital, Wroclaw, Poland
| | - Stanislaw Tubek
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Department of Cardiology, University Clinical Hospital, Wroclaw, Poland
| | | | - Wojciech Kosmala
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Department of Cardiology, University Clinical Hospital, Wroclaw, Poland
| | - Piotr Ponikowski
- Institute of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
- Department of Cardiology, University Clinical Hospital, Wroclaw, Poland
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6
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Distribution of leptin receptors in the brain stem: possible route in the pathophysiology of neuromuscular control of airway resistance during sleep. Sleep Med 2022; 93:56-62. [DOI: 10.1016/j.sleep.2022.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 03/06/2022] [Accepted: 03/19/2022] [Indexed: 11/20/2022]
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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.
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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.
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8
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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: 78] [Impact Index Per Article: 26.0] [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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9
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Yeung BHY, Griffiths K, Berger L, Paudel O, Shin MK, Rui L, Sham JSK, Polotsky VY, Tang WY. Leptin Induces Epigenetic Regulation of Transient Receptor Potential Melastatin 7 in Rat Adrenal Pheochromocytoma Cells. Am J Respir Cell Mol Biol 2021; 65:214-221. [PMID: 33891828 DOI: 10.1165/rcmb.2020-0374oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Obesity elevates the plasma level of leptin, which has been associated with hypertension. Our recent studies in mice demonstrated that leptin increases blood pressure by activating the carotid sinus nerve, which transmits the chemosensory input from carotid bodies (CBs) to the medullary centers, and that the effect of leptin is mediated via Trpm7 (TRP [transient receptor potential] melastatin 7) channels in CB glomus cells. We also found that Trpm7 overexpression and Trpm7 promoter demethylation in CBs correlate positively with the hyperleptinemia and leptin receptor overexpression in CBs. Hence, we postulated that leptin epigenetically regulates Trpm7 expression in CBs. We addressed our hypothesis by using rat adrenal pheochromocytoma (PC12) cells as a model of CB glomus cells. PC12 cells expressing LEPRb (long, active form of leptin receptor) showed dramatic induction of the promoter activity and expression of Trpm7 upon leptin treatment. The increased Trpm7 expression coincided with the reduction of CpG site-specific methylation and trimethylation of H3K27 (H3 [histone 3] K27 [lysine 27]) and the increase of acetylation of H3K27 and trimethylation of H3K4 (H3 lysine 4) at the Trpm7 promoter. The inhibitor of STAT3 (signal transducer and activator of transcription 3) signaling, SD1008, reversed the leptin-induced Trpm7 promoter activity via modulations of the binding of pSTAT3 (phosphorylated STAT3) and DNMT3B (DNA methyltransferase 3B) and modifications of H3K27 and H3K4 at the Trpm7 promoter. Our results suggest that leptin-activated pSTAT3 epigenetically regulates the transcription of Trpm7 through DNA methylation and histone modifications. Because epigenetic changes are reversible, targeting epigenetic modifications of Trpm7 may serve as a new therapeutic approach for the treatment of hypertension in obesity.
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Affiliation(s)
- Bonnie Ho-Yee Yeung
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, and.,Division of Pulmonary and Critical Care Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Kelly Griffiths
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, and
| | - Liron Berger
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Omkar Paudel
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Mi-Kyung Shin
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Liangyou Rui
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, University of Michigan, Ann Arbor, Michigan
| | - James S K Sham
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, and.,Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Vsevolod Y Polotsky
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Wan-Yee Tang
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, and.,Division of Pulmonary and Critical Care Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland
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10
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Stocco E, Sfriso MM, Borile G, Contran M, Barbon S, Romanato F, Macchi V, Guidolin D, De Caro R, Porzionato A. Experimental Evidence of A 2A-D 2 Receptor-Receptor Interactions in the Rat and Human Carotid Body. Front Physiol 2021; 12:645723. [PMID: 33935801 PMCID: PMC8082109 DOI: 10.3389/fphys.2021.645723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/09/2021] [Indexed: 12/26/2022] Open
Abstract
Adenosine A2A receptors (A2AR) and dopamine D2 receptors (D2R) are known to be involved in the physiological response to hypoxia, and their expression/activity may be modulated by chronic sustained or intermittent hypoxia. To date, A2AR and D2R can form transient physical receptor–receptor interactions (RRIs) giving rise to a dynamic equilibrium able to influence ligand binding and signaling, as demonstrated in different native tissues and transfected mammalian cell systems. Given the presence of A2AR and D2R in type I cells, type II cells, and afferent nerve terminals of the carotid body (CB), the aim of this work was to demonstrate here, for the first time, the existence of A2AR–D2R heterodimers by in situ proximity ligation assay (PLA). Our data by PLA analysis and tyrosine hydroxylase/S100 colocalization indicated the formation of A2AR–D2R heterodimers in type I and II cells of the CB; the presence of A2AR–D2R heterodimers also in afferent terminals is also suggested by PLA signal distribution. RRIs could play a role in CB dynamic modifications and plasticity in response to development/aging and environmental stimuli, including chronic intermittent/sustained hypoxia. Exploring other RRIs will allow for a broad comprehension of the regulative mechanisms these interactions preside over, with also possible clinical implications.
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Affiliation(s)
- Elena Stocco
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padua, Italy
| | - Maria Martina Sfriso
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padua, Italy
| | - Giulia Borile
- Department of Physics and Astronomy "G. Galilei," University of Padova, Padua, Italy.,Institute of Pediatric Research Città della Speranza, Padua, Italy
| | - Martina Contran
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padua, Italy
| | - Silvia Barbon
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padua, Italy
| | - Filippo Romanato
- Department of Physics and Astronomy "G. Galilei," University of Padova, Padua, Italy.,Institute of Pediatric Research Città della Speranza, Padua, Italy
| | - Veronica Macchi
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padua, Italy
| | - Diego Guidolin
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padua, Italy
| | - Raffaele De Caro
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padua, Italy
| | - Andrea Porzionato
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padua, Italy
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11
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Conde SV, Sacramento JF, Martins FO. Immunity and the carotid body: implications for metabolic diseases. Bioelectron Med 2020; 6:24. [PMID: 33353562 PMCID: PMC7756955 DOI: 10.1186/s42234-020-00061-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
Neuro-immune communication has gained enormous interest in recent years due to increasing knowledge of the way in which the brain coordinates functional alterations in inflammatory and autoimmune responses, and the mechanisms of neuron-immune cell interactions in the context of metabolic diseases such as obesity and type 2 diabetes. In this review, we will explain how this relationship between the nervous and immune system impacts the pro- and anti-inflammatory pathways with specific reference to the hypothalamus-pituitary-adrenal gland axis and the vagal reflex and will explore the possible involvement of the carotid body (CB) in the neural control of inflammation. We will also highlight the mechanisms of vagal anti-inflammatory reflex control of immunity and metabolism, and the consequences of functional disarrangement of this reflex in settlement and development of metabolic diseases, with special attention to obesity and type 2 diabetes. Additionally, the role of CB in the interplay between metabolism and immune responses will be discussed, with specific reference to the different stimuli that promote CB activation and the balance between sympathetic and parasympathetic in this context. In doing so, we clarify the multivarious neuronal reflexes that coordinate tissue-specific responses (gut, pancreas, adipose tissue and liver) critical to metabolic control, and metabolic disease settlement and development. In the final section, we will summarize how electrical modulation of the carotid sinus nerve may be utilized to adjust these reflex responses and thus control inflammation and metabolic diseases, envisioning new therapeutics horizons.
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Affiliation(s)
- Silvia V Conde
- iNOVA4Health, CEDOC, NOVA Medical School, NMS, Universidade Nova de Lisboa, Rua Câmara Pestana, n°6, Edifício 2, piso 3, 1150-274, Lisbon, Portugal.
| | - Joana F Sacramento
- iNOVA4Health, CEDOC, NOVA Medical School, NMS, Universidade Nova de Lisboa, Rua Câmara Pestana, n°6, Edifício 2, piso 3, 1150-274, Lisbon, Portugal
| | - Fatima O Martins
- iNOVA4Health, CEDOC, NOVA Medical School, NMS, Universidade Nova de Lisboa, Rua Câmara Pestana, n°6, Edifício 2, piso 3, 1150-274, Lisbon, Portugal
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12
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A Leptin-Mediated Neural Mechanism Linking Breathing to Metabolism. Cell Rep 2020; 33:108358. [PMID: 33176139 DOI: 10.1016/j.celrep.2020.108358] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/27/2020] [Accepted: 10/16/2020] [Indexed: 01/10/2023] Open
Abstract
Breathing is coupled to metabolism. Leptin, a peptide mainly secreted in proportion to adipose tissue mass, increases energy expenditure with a parallel increase in breathing. We demonstrate that optogenetic activation of LepRb neurons in the nucleus of the solitary tract (NTS) mimics the respiratory stimulation after systemic leptin administration. We show that leptin activates the sodium leak channel (NALCN), thereby depolarizing a subset of glutamatergic (VGluT2) LepRb NTS neurons expressing galanin. Mice with selective deletion of NALCN in LepRb neurons have increased breathing irregularity and central apneas. On a high-fat diet, these mice gain weight with an associated depression of minute ventilation and tidal volume, which are not detected in control littermates. Anatomical mapping reveals LepRb NTS-originating glutamatergic axon terminals in a brainstem inspiratory premotor region (rVRG) and dorsomedial hypothalamus. These findings directly link a defined subset of NTS LepRb cells to the matching of ventilation to energy balance.
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13
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Leptin mediate central obesity on the severity of cardiovascular autonomic neuropathy in well-controlled type 2 diabetes and prediabetes. J Transl Med 2020; 18:396. [PMID: 33076921 PMCID: PMC7574496 DOI: 10.1186/s12967-020-02559-7] [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: 07/02/2020] [Accepted: 10/03/2020] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Evidences support the view that central obesity is an independently cardiovascular risk. It is thought that leptin contributes to autonomic dysfunction and cardiovascular risks in type 1 and type 2 diabetes mellitus (T1DM and T2DM). This raises the possibility that leptin might mediate the relationship between central obesity and the severity of cardiovascular autonomic neuropathy (CAN) in patients with well-controlled T2DM and prediabetes. METHODS The complete cardiovascular reflex tests and biomarkers were assessed for each patient. The severity of CAN was assessed using composite autonomic scoring scale (CASS). A single-level three-variable mediation model was used to investigate the possible relationships among central obesity [as indicated by waist circumference (WC)], leptin level, and severity of CAN (as indicated by CASS value). RESULTS A total of 107 patients were included in this study: 90 with diabetes and 17 with prediabetes. The results demonstrate that increased WC is associated with increased severity of CAN (r = 0.242, P = 0.017). We further discovered that leptin level is positively correlated with WC (r = 0.504, P < 0.0001) and the CASS value (r = 0.36, P < 0.0001). Further mediation analysis shows that leptin level serves as mediators between higher WC and higher CASS. CONCLUSIONS Our results highlighted the relationship among leptin, central obesity, and severity of CAN. As the leptin level serves as mediator between central obesity and severity of CAN, a longitudinal study is needed to confirm that control of WC can decrease leptin levels and can be effective in reducing CAN progression.
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Badoer E. The Carotid Body a Common Denominator for Cardiovascular and Metabolic Dysfunction? Front Physiol 2020; 11:1069. [PMID: 32982794 PMCID: PMC7478291 DOI: 10.3389/fphys.2020.01069] [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: 01/31/2020] [Accepted: 08/04/2020] [Indexed: 11/28/2022] Open
Abstract
The carotid body is a highly vascularized organ designed to monitor oxygen levels. Reducing oxygen levels in blood results in increased activity of the carotid body cells and reflex increases in sympathetic nerve activity. A key contributor to elevated sympathetic nerve activity in neurogenic forms of hypertension is enhanced peripheral chemoreceptor activity. Hypertension commonly occurs in metabolic disorders, like obesity. Such metabolic diseases are serious global health problems. Yet, the mechanisms contributing to increased sympathetic nerve activity and hypertension in obesity are not fully understood and a better understanding is urgently required. In this review, we examine the literature that suggests that overactivity of the carotid body may also contribute to metabolic disturbances. The purine ATP is an important chemical mediator influencing the activity of the carotid body and the role of purines in the overactivity of the carotid body is explored. We will conclude with the suggestion that tonic overactivity of the carotid body may be a common denominator that contributes to the hypertension and metabolic dysfunction seen in conditions in which metabolic disease exists such as obesity or insulin resistance induced by high caloric intake. Therapeutic treatment targeting the carotid bodies may be a viable treatment since translation to the clinic could be more easily performed than expected via repurposing antagonists of purinergic receptors currently in clinical practice, and the use of other minimally invasive techniques that reduce the overactivity of the carotid bodies which may be developed for such clinical use.
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Affiliation(s)
- Emilio Badoer
- School of Health and Biomedical Sciences, Royal Melbourne Institute of Technology (RMIT) University, Melbourne, VIC, Australia
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15
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Exploring the Mediators that Promote Carotid Body Dysfunction in Type 2 Diabetes and Obesity Related Syndromes. Int J Mol Sci 2020; 21:ijms21155545. [PMID: 32756352 PMCID: PMC7432672 DOI: 10.3390/ijms21155545] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/26/2020] [Accepted: 07/30/2020] [Indexed: 12/12/2022] Open
Abstract
Carotid bodies (CBs) are peripheral chemoreceptors that sense changes in blood O2, CO2, and pH levels. Apart from ventilatory control, these organs are deeply involved in the homeostatic regulation of carbohydrates and lipid metabolism and inflammation. It has been described that CB dysfunction is involved in the genesis of metabolic diseases and that CB overactivation is present in animal models of metabolic disease and in prediabetes patients. Additionally, resection of the CB-sensitive nerve, the carotid sinus nerve (CSN), or CB ablation in animals prevents and reverses diet-induced insulin resistance and glucose intolerance as well as sympathoadrenal overactivity, meaning that the beneficial effects of decreasing CB activity on glucose homeostasis are modulated by target-related efferent sympathetic nerves, through a reflex initiated in the CBs. In agreement with our pre-clinical data, hyperbaric oxygen therapy, which reduces CB activity, improves glucose homeostasis in type 2 diabetes patients. Insulin, leptin, and pro-inflammatory cytokines activate the CB. In this manuscript, we review in a concise manner the putative pathways linking CB chemoreceptor deregulation with the pathogenesis of metabolic diseases and discuss and present new data that highlight the roles of hyperinsulinemia, hyperleptinemia, and chronic inflammation as major factors contributing to CB dysfunction in metabolic disorders.
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16
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Kim LJ, Polotsky VY. Carotid Body and Metabolic Syndrome: Mechanisms and Potential Therapeutic Targets. Int J Mol Sci 2020; 21:E5117. [PMID: 32698380 PMCID: PMC7404212 DOI: 10.3390/ijms21145117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/11/2020] [Accepted: 07/16/2020] [Indexed: 12/19/2022] Open
Abstract
The carotid body (CB) is responsible for the peripheral chemoreflex by sensing blood gases and pH. The CB also appears to act as a peripheral sensor of metabolites and hormones, regulating the metabolism. CB malfunction induces aberrant chemosensory responses that culminate in the tonic overactivation of the sympathetic nervous system. The sympatho-excitation evoked by CB may contribute to the pathogenesis of metabolic syndrome, inducing systemic hypertension, insulin resistance and sleep-disordered breathing. Several molecular pathways are involved in the modulation of CB activity, and their pharmacological manipulation may lead to overall benefits for cardiometabolic diseases. In this review, we will discuss the role of the CB in the regulation of metabolism and in the pathogenesis of the metabolic dysfunction induced by CB overactivity. We will also explore the potential pharmacological targets in the CB for the treatment of metabolic syndrome.
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Affiliation(s)
- Lenise J. Kim
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD 21224, USA;
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17
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Gauda EB, Conde S, Bassi M, Zoccal DB, Almeida Colombari DS, Colombari E, Despotovic N. Leptin: Master Regulator of Biological Functions that Affects Breathing. Compr Physiol 2020; 10:1047-1083. [PMID: 32941688 DOI: 10.1002/cphy.c190031] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Obesity is a global epidemic in developed countries accounting for many of the metabolic and cardiorespiratory morbidities that occur in adults. These morbidities include type 2 diabetes, sleep-disordered breathing (SDB), obstructive sleep apnea, chronic intermittent hypoxia, and hypertension. Leptin, produced by adipocytes, is a master regulator of metabolism and of many other biological functions including central and peripheral circuits that control breathing. By binding to receptors on cells and neurons in the brainstem, hypothalamus, and carotid body, leptin links energy and metabolism to breathing. In this comprehensive article, we review the central and peripheral locations of leptin's actions that affect cardiorespiratory responses during health and disease, with a particular focus on obesity, SDB, and its effects during early development. Obesity-induced hyperleptinemia is associated with centrally mediated hypoventilation with decrease CO2 sensitivity. On the other hand, hyperleptinemia augments peripheral chemoreflexes to hypoxia and induces sympathoexcitation. Thus, "leptin resistance" in obesity is relative. We delineate the circuits responsible for these divergent effects, including signaling pathways. We review the unique effects of leptin during development on organogenesis, feeding behavior, and cardiorespiratory responses, and how undernutrition and overnutrition during critical periods of development can lead to cardiorespiratory comorbidities in adulthood. We conclude with suggestions for future directions to improve our understanding of leptin dysregulation and associated clinical diseases and possible therapeutic targets. Lastly, we briefly discuss the yin and the yang, specifically the contribution of relative adiponectin deficiency in adults with hyperleptinemia to the development of metabolic and cardiovascular disease. © 2020 American Physiological Society. Compr Physiol 10:1047-1083, 2020.
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Affiliation(s)
- Estelle B Gauda
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Silvia Conde
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Lisboa, Portugal
| | - Mirian Bassi
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Daniel B Zoccal
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Debora Simoes Almeida Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil
| | - Nikola Despotovic
- Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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18
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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.
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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
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19
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Shin MK, Eraso CC, Mu YP, Gu C, Yeung BHY, Kim LJ, Liu XR, Wu ZJ, Paudel O, Pichard LE, Shirahata M, Tang WY, Sham JSK, Polotsky VY. Leptin Induces Hypertension Acting on Transient Receptor Potential Melastatin 7 Channel in the Carotid Body. Circ Res 2019; 125:989-1002. [PMID: 31545149 PMCID: PMC6842127 DOI: 10.1161/circresaha.119.315338] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
RATIONALE Obesity leads to resistant hypertension and mechanisms are poorly understood, but high plasma levels of leptin have been implicated. Leptin increases blood pressure acting both centrally in the dorsomedial hypothalamus and peripherally. Sites of the peripheral hypertensive effect of leptin have not been identified. We previously reported that leptin enhanced activity of the carotid sinus nerve, which transmits chemosensory input from the carotid bodies (CBs) to the medullary centers, and this effect was abolished by nonselective blockers of Trp (transient receptor potential) channels. We searched our mouse CB transcriptome database and found that the Trpm7 (transient receptor potential melastatin 7) channel was the most abundant Trp channel. OBJECTIVE To examine if leptin induces hypertension acting on the CB Trpm7. METHODS AND RESULTS C57BL/6J (n=79), leptin receptor (LepRb) deficient db/db mice (n=22), and LepRb-EGFP (n=4) mice were used. CB Trpm7 and LepRb gene expression was determined and immunohistochemistry was performed; CB glomus cells were isolated and Trpm7-like current was recorded. Blood pressure was recorded continuously in (1) leptin-treated C57BL/6J mice with intact and denervated CB; (2) leptin-treated C57BL/6J mice, which also received a nonselective Trpm7 blocker FTY720 administered systemically or topically to the CB area; (3) leptin-treated C57BL/6J mice transfected with Trpm7 small hairpin RNA to the CB, and (4) Leprb deficient obese db/db mice before and after Leprb expression in CB. Leptin receptor and Trpm7 colocalized in the CB glomus cells. Leptin induced a nonselective cation current in these cells, which was inhibited by Trpm7 blockers. Leptin induced hypertension in C57BL/6J mice, which was abolished by CB denervation, Trpm 7 blockers, and Trpm7 small hairpin RNA applied to CBs. Leprb overexpression in CB of Leprb-deficient db/db mice demethylated the Trpm7 promoter, increased Trpm7 gene expression, and induced hypertension. CONCLUSIONS We conclude that leptin induces hypertension acting on Trmp7 in CB, which opens horizons for new therapy.
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Affiliation(s)
- Mi-Kyung Shin
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (M.-K.S., C.G., B.H.Y.Y., L.J.K., J.S.K.S., V.Y.P.)
| | - Candela Caballero Eraso
- Unidad Médico-Quirúrgica de Enfermedades Respiratorias, Instituto de Biomedicina de Sevilla (IBiS), Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Hospital Universitario Virgen del Rocío/Universidad de Sevilla, Spain (C.C.E.)
| | - Yun-Ping Mu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China (Y.-P.M., X.-R.L., Z.-J.W.)
| | - Chenjuan Gu
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (M.-K.S., C.G., B.H.Y.Y., L.J.K., J.S.K.S., V.Y.P.)
| | - Bonnie H Y Yeung
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (M.-K.S., C.G., B.H.Y.Y., L.J.K., J.S.K.S., V.Y.P.)
| | - Lenise J Kim
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (M.-K.S., C.G., B.H.Y.Y., L.J.K., J.S.K.S., V.Y.P.)
- Departamento de Psicobiologia, Universidade Federal de São Paulo, Brazil (L.J.K.)
| | - Xiao-Ru Liu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China (Y.-P.M., X.-R.L., Z.-J.W.)
| | - Zhi-Juan Wu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China (Y.-P.M., X.-R.L., Z.-J.W.)
| | - Omkar Paudel
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (O.P., L.E.P., M.S.)
| | - Luis E Pichard
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (O.P., L.E.P., M.S.)
| | - Machiko Shirahata
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (O.P., L.E.P., M.S.)
| | | | - James S K Sham
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (M.-K.S., C.G., B.H.Y.Y., L.J.K., J.S.K.S., V.Y.P.)
| | - Vsevolod Y Polotsky
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (M.-K.S., C.G., B.H.Y.Y., L.J.K., J.S.K.S., V.Y.P.)
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20
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Zhang WF, Jin YC, Li XM, Yang Z, Wang D, Cui JJ. Protective effects of leptin against cerebral ischemia/reperfusion injury. Exp Ther Med 2019; 17:3282-3290. [PMID: 30988703 PMCID: PMC6447799 DOI: 10.3892/etm.2019.7377] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 02/04/2019] [Indexed: 12/12/2022] Open
Abstract
In recent years, the use of thrombolytic therapy for treating ischemia/reperfusion injury has resulted in damage to the self-regulatory mechanisms of the brain. This is due to the increased production of free radicals, excitatory amino acids and pro-inflammatory cytokines causing secondary damage to the brain. Simple thrombolytic therapy has not been the best approach for treating ischemia/reperfusion injury. Excessive perfusion leads to failure of the body's self-regulatory functions, which in turn increases the area of cerebral edema and aggravates cerebral ischemia. Previous studies have evaluated the satiety hormone leptin as a link between energy expenditure and obesity. Of note, leptin, which is involved in brain development, synaptic transmission and angiogenesis following ischemia/reperfusion injury, has been considered an important factor for treating ischemia/reperfusion injury. The present review outlines the discovery of leptin and discusses its association with cerebral ischemia/reperfusion.
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Affiliation(s)
- Wen-Fang Zhang
- Department of Biomedical Research Center, Binzhou Medical University, Yantai, Shandong 264000, P.R. China
| | - Yin-Chuan Jin
- Department of Histology and Embryology, Binzhou Medical University, Yantai, Shandong 264000, P.R. China
| | - Xiao-Mei Li
- Department of Cardiology, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong 264000, P.R. China
| | - Zhi Yang
- Department of Cardiology, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong 264000, P.R. China
| | - Dong Wang
- Department of Cardiology, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong 264000, P.R. China
| | - Jing-Jing Cui
- Department of Medical Affairs, Affiliated Hospital of Binzhou Medical College, Binzhou, Shandong 256603, P.R. China
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21
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Caballero-Eraso C, Shin MK, Pho H, Kim LJ, Pichard LE, Wu ZJ, Gu C, Berger S, Pham L, Yeung HYB, Shirahata M, Schwartz AR, Tang WYW, Sham JSK, Polotsky VY. Leptin acts in the carotid bodies to increase minute ventilation during wakefulness and sleep and augment the hypoxic ventilatory response. J Physiol 2018; 597:151-172. [PMID: 30285278 DOI: 10.1113/jp276900] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/03/2018] [Indexed: 01/10/2023] Open
Abstract
KEY POINTS Leptin is a potent respiratory stimulant. A long functional isoform of leptin receptor, LepRb , was detected in the carotid body (CB), a key peripheral hypoxia sensor. However, the effect of leptin on minute ventilation (VE ) and the hypoxic ventilatory response (HVR) has not been sufficiently studied. We report that LepRb is present in approximately 74% of the CB glomus cells. Leptin increased carotid sinus nerve activity at baseline and in response to hypoxia in vivo. Subcutaneous infusion of leptin increased VE and HVR in C57BL/6J mice and this effect was abolished by CB denervation. Expression of LepRb in the carotid bodies of LepRb deficient obese db/db mice increased VE during wakefulness and sleep and augmented the HVR. We conclude that leptin acts on LepRb in the CBs to stimulate breathing and HVR, which may protect against sleep disordered breathing in obesity. ABSTRACT Leptin is a potent respiratory stimulant. The carotid bodies (CB) express the long functional isoform of leptin receptor, LepRb , but the role of leptin in CB has not been fully elucidated. The objectives of the current study were (1) to examine the effect of subcutaneous leptin infusion on minute ventilation (VE ) and the hypoxic ventilatory response to 10% O2 (HVR) in C57BL/6J mice before and after CB denervation; (2) to express LepRb in CB of LepRb -deficient obese db/db mice and examine its effects on breathing during sleep and wakefulness and on HVR. We found that leptin enhanced carotid sinus nerve activity at baseline and in response to 10% O2 in vivo. In C57BL/6J mice, leptin increased VE from 1.1 to 1.5 mL/min/g during normoxia (P < 0.01) and from 3.6 to 4.7 mL/min/g during hypoxia (P < 0.001), augmenting HVR from 0.23 to 0.31 mL/min/g/Δ F I O 2 (P < 0.001). The effects of leptin on VE and HVR were abolished by CB denervation. In db/db mice, LepRb expression in CB increased VE from 1.1 to 1.3 mL/min/g during normoxia (P < 0.05) and from 2.8 to 3.2 mL/min/g during hypoxia (P < 0.02), increasing HVR. Compared to control db/db mice, LepRb transfected mice showed significantly higher VE throughout non-rapid eye movement (20.1 vs. -27.7 mL/min respectively, P < 0.05) and rapid eye movement sleep (16.5 vs 23.4 mL/min, P < 0.05). We conclude that leptin acts in CB to augment VE and HVR, which may protect against sleep disordered breathing in obesity.
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Affiliation(s)
- Candela Caballero-Eraso
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Unidad Médico-Quirúrgica de Enfermedades Respiratorias, Instituto de Biomedicina de Sevilla (IBiS), Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Hospital Universitario Virgen del Rocío/Universidad de Sevilla, Sevilla, Spain
| | - Mi-Kyung Shin
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Huy Pho
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lenise J Kim
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Luis E Pichard
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zhi-Juan Wu
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chenjuan Gu
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Slava Berger
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Luu Pham
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ho-Yee Bonnie Yeung
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Machiko Shirahata
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Alan R Schwartz
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Wan-Yee Winnie Tang
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - James S K Sham
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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22
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Porzionato A, Macchi V, Stecco C, De Caro R. The Carotid Sinus Nerve-Structure, Function, and Clinical Implications. Anat Rec (Hoboken) 2018; 302:575-587. [PMID: 29663677 DOI: 10.1002/ar.23829] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 06/24/2017] [Accepted: 08/01/2017] [Indexed: 12/12/2022]
Abstract
Interest has been renewed in the anatomy and physiology of the carotid sinus nerve (CSN) and its targets (carotid sinus and carotid body, CB), due to recent proposals of surgical procedures for a series of common pathologies, such as carotid sinus syndrome, hypertension, heart failure, and insulin resistance. The CSN originates from the glossopharyngeal nerve soon after its appearance from the jugular foramen. It shows frequent communications with the sympathetic trunk (usually at the level of the superior cervical ganglion) and the vagal nerve (main trunk, pharyngeal branches, or superior laryngeal nerve). It courses on the anterior aspect of the internal carotid artery to reach the carotid sinus, CB, and/or intercarotid plexus. In the carotid sinus, type I (dynamic) carotid baroreceptors have larger myelinated A-fibers; type II (tonic) baroreceptors show smaller A- and unmyelinated C-fibers. In the CB, afferent fibers are mainly stimulated by acetylcholine and ATP, released by type I cells. The neurons are located in the petrosal ganglion, and centripetal fibers project on to the solitary tract nucleus: chemosensory inputs to the commissural subnucleus, and baroreceptor inputs to the commissural, medial, dorsomedial, and dorsolateral subnuclei. The baroreceptor component of the CSN elicits sympatho-inhibition and the chemoreceptor component stimulates sympatho-activation. Thus, in refractory hypertension and heart failure (characterized by increased sympathetic activity), baroreceptor electrical stimulation, and CB removal have been proposed. Instead, denervation of the carotid sinus has been proposed for the "carotid sinus syndrome." Anat Rec, 302:575-587, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Andrea Porzionato
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padova, Italy
| | - Veronica Macchi
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padova, Italy
| | - Carla Stecco
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padova, Italy
| | - Raffaele De Caro
- Department of Neuroscience, Institute of Human Anatomy, University of Padova, Padova, Italy
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Leverton H, England C, Baxandall A. Carotid body activity - are we eating our way into the ventilatory pathway? J Physiol 2018; 596:2963-2964. [PMID: 29701248 DOI: 10.1113/jp276077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Hannah Leverton
- School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Cailey England
- School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Ashtyn Baxandall
- School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
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Yuan F, Wang H, Feng J, Wei Z, Yu H, Zhang X, Zhang Y, Wang S. Leptin Signaling in the Carotid Body Regulates a Hypoxic Ventilatory Response Through Altering TASK Channel Expression. Front Physiol 2018; 9:249. [PMID: 29636698 PMCID: PMC5881163 DOI: 10.3389/fphys.2018.00249] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 03/06/2018] [Indexed: 11/23/2022] Open
Abstract
Leptin is an adipose-derived hormone that plays an important role in the regulation of breathing. It has been demonstrated that obesity-related hypoventilation or apnea is closely associated with leptin signaling pathways. Perturbations of leptin signaling probably contribute to the reduced sensitivity of respiratory chemoreceptors to hypoxia/hypercapnia. However, the underlying mechanism remains incompletely understood. The present study is to test the hypothesis that leptin signaling contributes to modulating a hypoxic ventilatory response. The respiratory function was assessed in conscious obese Zucker rats or lean littermates treated with an injection of leptin. During exposure to hypoxia, the change in minute ventilation was lower in obese Zucker rats than chow-fed lean littermates or high fat diet-fed littermates. Such a change was abolished in all groups after carotid body denervation. In addition, the expression of phosphorylated signal transducers and activators of transcription 3 (pSTAT3), as well as putative O2-sensitive K+ channels including TASK-1, TASK-3 and TASK-2 in the carotid body, was significantly reduced in obese Zucker rats compared with the other two phenotype littermates. Chronic administration of leptin in chow-fed lean Zucker rats failed to alter basal ventilation but vigorously increased tidal volume, respiratory frequency, and therefore minute volume during exposure to hypoxia. Likewise, carotid body denervation abolished such an effect. In addition, systemic leptin elicited enhanced expression of pSTAT3 and TASK channels. In conclusion, these data demonstrate that leptin signaling facilitates hypoxic ventilatory responses probably through upregulation of pSTAT3 and TASK channels in the carotid body. These findings may help to better understand the pathogenic mechanism of obesity-related hypoventilation or apnea.
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Affiliation(s)
- Fang Yuan
- Department of Physiology, Hebei Medical University, Shijiazhuang, China.,Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Shijiazhuang, China
| | - Hanqiao Wang
- Department of Sleep, Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Jiaqi Feng
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Ziqian Wei
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Hongxiao Yu
- Department of Physiology, Hebei Medical University, Shijiazhuang, China
| | - Xiangjian Zhang
- Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Shijiazhuang, China.,Department of Neurology, Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Yi Zhang
- Department of Physiology, Hebei Medical University, Shijiazhuang, China.,Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Shijiazhuang, China
| | - Sheng Wang
- Department of Physiology, Hebei Medical University, Shijiazhuang, China.,Hebei Key Laboratory of Vascular Homeostasis and Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Shijiazhuang, China
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25
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Leptin and Leptin Resistance in the Pathogenesis of Obstructive Sleep Apnea: A Possible Link to Oxidative Stress and Cardiovascular Complications. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:5137947. [PMID: 29675134 PMCID: PMC5841044 DOI: 10.1155/2018/5137947] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 01/05/2018] [Accepted: 01/23/2018] [Indexed: 12/17/2022]
Abstract
Obesity-related sleep breathing disorders such as obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS) cause intermittent hypoxia (IH) during sleep, a powerful trigger of oxidative stress. Obesity also leads to dramatic increases in circulating levels of leptin, a hormone produced in adipose tissue. Leptin acts in the hypothalamus to suppress food intake and increase metabolic rate. However, obese individuals are resistant to metabolic effects of leptin. Leptin also activates the sympathetic nervous system without any evidence of resistance, possibly because these effects occur peripherally without a need to penetrate the blood-brain barrier. IH is a potent stimulator of leptin expression and release from adipose tissue. Hyperleptinemia and leptin resistance may upregulate generation of reactive oxygen species, increasing oxidative stress and promoting inflammation. The current review summarizes recent data on a possible link between leptin and oxidative stress in the pathogenesis of sleep breathing disorders.
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Ribeiro MJ, Sacramento JF, Gallego-Martin T, Olea E, Melo BF, Guarino MP, Yubero S, Obeso A, Conde SV. High fat diet blunts the effects of leptin on ventilation and on carotid body activity. J Physiol 2018; 596:3187-3199. [PMID: 29271068 DOI: 10.1113/jp275362] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 12/13/2017] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Leptin plays a role in the control of breathing, acting mainly on central nervous system; however, leptin receptors have been recently shown to be expressed in the carotid body (CB), and this finding suggests a physiological role for leptin in the regulation of CB function. Leptin increases minute ventilation in both basal and hypoxic conditions in rats. It increases the frequency of carotid sinus nerve discharge in basal conditions, as well as the release of adenosine from the CB. However, in a metabolic syndrome animal model, the effects of leptin in ventilatory control, carotid sinus nerve activity and adenosine release by the CB are blunted. Although leptin may be involved in triggering CB overactivation in initial stages of obesity and dysmetabolism, resistance to leptin signalling and blunting of responses develops in metabolic syndrome animal models. ABSTRACT Leptin plays a role in the control of breathing, acting mainly on central nervous system structures. Leptin receptors are expressed in the carotid body (CB) and this finding has been associated with a putative physiological role of leptin in the regulation of CB function. Since, the CBs are implicated in energy metabolism, here we tested the effects of different concentrations of leptin administration on ventilatory parameters and on carotid sinus nerve (CSN) activity in control and high-fat (HF) diet fed rats, in order to clarify the role of leptin in ventilation control in metabolic disease states. We also investigated the expression of leptin receptors and the neurotransmitters involved in leptin signalling in the CBs. We found that in non-disease conditions, leptin increases minute ventilation in both basal and hypoxic conditions. However, in the HF model, the effect of leptin in ventilatory control is blunted. We also observed that HF rats display an increased frequency of CSN discharge in basal conditions that is not altered by leptin, in contrast to what is observed in control animals. Leptin did not modify intracellular Ca2+ in CB chemoreceptor cells, but it produced an increase in the release of adenosine from the whole CB. We conclude that CBs represent an important target for leptin signalling, not only to coordinate peripheral ventilatory chemoreflexive drive, but probably also to modulate metabolic variables. We also concluded that leptin signalling is mediated by adenosine release and that HF diets blunt leptin responses in the CB, compromising ventilatory adaptation.
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Affiliation(s)
- Maria J Ribeiro
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Joana F Sacramento
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Teresa Gallego-Martin
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina, Instituto de Biología y Genética Molecular, CSIC, Ciber de Enfermedades Respiratorias, CIBERES, Valladolid, Spain
| | - Elena Olea
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina, Instituto de Biología y Genética Molecular, CSIC, Ciber de Enfermedades Respiratorias, CIBERES, Valladolid, Spain
| | - Bernardete F Melo
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Maria P Guarino
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal.,School of Health Sciences, Polytechnic Institute of Leiria, Leiria, Portugal
| | - Sara Yubero
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina, Instituto de Biología y Genética Molecular, CSIC, Ciber de Enfermedades Respiratorias, CIBERES, Valladolid, Spain
| | - Ana Obeso
- Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina, Instituto de Biología y Genética Molecular, CSIC, Ciber de Enfermedades Respiratorias, CIBERES, Valladolid, Spain
| | - Silvia V Conde
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
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27
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Rakoczy RJ, Pye RL, Fayyad TH, Santin JM, Barr BL, Wyatt CN. High Fat Feeding in Rats Alters Respiratory Parameters by a Mechanism That Is Unlikely to Be Mediated by Carotid Body Type I Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1071:137-142. [DOI: 10.1007/978-3-319-91137-3_17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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28
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Gauda EB, Master Z. Contribution of relative leptin and adiponectin deficiencies in premature infants to chronic intermittent hypoxia: Exploring a new hypothesis. Respir Physiol Neurobiol 2017; 256:119-127. [PMID: 29246449 DOI: 10.1016/j.resp.2017.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 11/08/2017] [Accepted: 12/06/2017] [Indexed: 12/15/2022]
Abstract
Chronic intermittent hypoxia (CIH) occurs frequently in premature infants who have apnea of prematurity. Immaturity of the respiratory network from low central respiratory drive and the greater contribution of the carotid body on baseline breathing leads to respiratory instability in premature infants presenting as apnea and periodic breathing. During the 2nd week after birth, the smallest and the youngest premature infants have increased frequency of apnea and periodic breathing and associated oxygen desaturations that can persist for weeks after birth. CIH increases the production of reactive oxygen species that causes tissue damage. Premature infants have decreased capacity to scavenge reactive oxygen species. Oxidative injury is the cause of many of the co-morbidities that are seen in premature infants. In this review we discuss who low fat mass and the resulting relative deficiencies in leptin and adiponectin could contribute to the increase frequency of oxygen desaturations that occurs days after birth in the smallest and youngest premature infants. Leptin is a central respiratory stimulant and adiponectin protects the lung from vascular leak, oxidative injury and vascular remodeling.
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Affiliation(s)
- Estelle B Gauda
- The Hospital for Sick Children, Division of Neonatology, 555 University Ave, Toronto, Ontario, M5G 1X8, Canada.
| | - Zankhana Master
- Department of Pediatrics, Division of Neonatology, University of Missouri, Columbia, MO 65211, United States.
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29
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Kaczyńska K, Zając D, Wojciechowski P, Kogut E, Szereda-Przestaszewska M. Neuropeptides and breathing in health and disease. Pulm Pharmacol Ther 2017; 48:217-224. [PMID: 29223509 DOI: 10.1016/j.pupt.2017.12.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/20/2017] [Accepted: 12/05/2017] [Indexed: 12/18/2022]
Abstract
Regulatory neuropeptides control and regulate breathing in physiological and pathophysiological conditions. While they have been identified in the neurons of major respiratory areas, they can be active not only at the central level, but also at the periphery via chemoreceptors, vagal afferents, or locally within lungs and airways. Some neuropeptides, such as leptin or substance P, are respiratory stimulants; others, such as neurotensin, produce variable effects on respiration depending on the site of application. Some neuropeptides have been implicated in pathological states, such as obstructive sleep apnea or asthma. This article provides a concise review of the possible role and functions of several selected neuropeptides in the process of breathing in health and disease and in lung pathologies.
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Affiliation(s)
- Katarzyna Kaczyńska
- Laboratory of Respiration Physiology, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland.
| | - Dominika Zając
- Laboratory of Respiration Physiology, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
| | - Piotr Wojciechowski
- Laboratory of Respiration Physiology, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
| | - Ewelina Kogut
- Laboratory of Respiration Physiology, Mossakowski Medical Research Centre Polish Academy of Sciences, Warsaw, Poland
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30
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Conde SV, Ribeiro MJ, Melo BF, Guarino MP, Sacramento JF. Insulin resistance: a new consequence of altered carotid body chemoreflex? J Physiol 2017; 595:31-41. [PMID: 27027507 PMCID: PMC5199745 DOI: 10.1113/jp271684] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/11/2016] [Indexed: 01/22/2023] Open
Abstract
Metabolic diseases affect millions of individuals across the world and represent a group of chronic diseases of very high prevalence and relatively low therapeutic success, making them suitable candidates for pathophysiological studies. The sympathetic nervous system (SNS) contributes to the regulation of energy balance and energy expenditure both in physiological and pathological states. For instance, drugs that stimulate sympathetic activity decrease food intake, increase resting metabolic rate and increase the thermogenic response to food, while pharmacological blockade of the SNS has opposite effects. Likewise, dysmetabolic features such as insulin resistance, dyslipidaemia and obesity are characterized by a basal overactivation of the SNS. Recently, a new line of research linking the SNS to metabolic diseases has emerged with the report that the carotid bodies (CBs) are involved in the development of insulin resistance. The CBs are arterial chemoreceptors that classically sense changes in arterial blood O2 , CO2 and pH levels and whose activity is known to be increased in rodent models of insulin resistance. We have shown that selective bilateral resection of the nerve of the CB, the carotid sinus nerve (CSN), totally prevents diet-induced insulin resistance, hyperglycaemia, dyslipidaemia, hypertension and sympathoadrenal overactivity. These results imply that the beneficial effects of CSN resection on insulin action and glucoregulation are modulated by target-related efferent sympathetic nerves through a reflex that is initiated in the CBs. It also highlights modulation of CB activity as a putative future therapeutic intervention for metabolic diseases.
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Affiliation(s)
- Silvia V. Conde
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências MédicasUniversidade Nova de LisboaLisboaPortugal
| | - Maria J. Ribeiro
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências MédicasUniversidade Nova de LisboaLisboaPortugal
| | - Bernardete F. Melo
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências MédicasUniversidade Nova de LisboaLisboaPortugal
| | - Maria P. Guarino
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências MédicasUniversidade Nova de LisboaLisboaPortugal
- UIS‐Unidade de Investigação em Saúde – Escola Superior de Saúde de Leiria – Instituto Politécnico de LeiriaLeiriaPortugal
| | - Joana F. Sacramento
- CEDOC, Centro Estudos Doenças Crónicas, NOVA Medical School, Faculdade de Ciências MédicasUniversidade Nova de LisboaLisboaPortugal
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31
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Thon M, Hosoi T, Ozawa K. Possible Integrative Actions of Leptin and Insulin Signaling in the Hypothalamus Targeting Energy Homeostasis. Front Endocrinol (Lausanne) 2016; 7:138. [PMID: 27812350 PMCID: PMC5071376 DOI: 10.3389/fendo.2016.00138] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 10/07/2016] [Indexed: 12/17/2022] Open
Abstract
Obesity has emerged as one of the most burdensome conditions in modern society. In this context, understanding the mechanisms controlling food intake is critical. At present, the adipocyte-derived hormone leptin and the pancreatic β-cell-derived hormone insulin are considered the principal anorexigenic hormones. Although leptin and insulin signal transduction pathways are distinct, their regulation of body weight maintenance is concerted. Resistance to the central actions of leptin or insulin is linked to the emergence of obesity and diabetes mellitus. A growing body of evidence suggests a convergence of leptin and insulin intracellular signaling at the insulin-receptor-substrate-phosphatidylinositol-3-kinase level. Moreover, numerous factors mediating the pathophysiology of leptin resistance, a hallmark of obesity, such as endoplasmic reticulum stress, protein tyrosine phosphatase 1B, and suppressor of cytokine signaling 3 also contribute to insulin resistance. Recent studies have also indicated that insulin potentiates leptin-induced signaling. Thus, a greater understanding of the overlapping functions of leptin and insulin in the central nervous system is vital to understand the associated physiological and pathophysiological states. This mini-review focuses on the cross talk and integrative signaling of leptin and insulin in the regulation of energy homeostasis in the brain.
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Affiliation(s)
- Mina Thon
- Department of Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Toru Hosoi
- Department of Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Koichiro Ozawa
- Department of Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
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32
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Paleczny B, Siennicka A, Zacharski M, Jankowska EA, Ponikowska B, Ponikowski P. Increased body fat is associated with potentiation of blood pressure response to hypoxia in healthy men: relations with insulin and leptin. Clin Auton Res 2016; 26:107-16. [PMID: 26781642 PMCID: PMC4819928 DOI: 10.1007/s10286-015-0338-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 12/16/2015] [Indexed: 12/18/2022]
Abstract
Background Increased peripheral chemosensitivity (PChS) has been proposed
as mechanism underlying obesity-related sympathoactivation, with insulin and/or leptin as possible mediators. However, human data on PChS in obesity are scarce. Therefore, we explored this issue in a sample of 41 healthy men aged 30–59 years, divided according to body fat percentage (fat %) into two groups: <25 and ≥25 %. Methods PChS was assessed using transient hypoxia method [respiratory (PChS-MV), heart rate (PChS-HR), and blood pressure (PChS-SBP) responses were calculated]. Baroreflex sensitivity (BRS-Seq) was assessed using sequence method. Fasting plasma insulin and leptin levels were measured. Homeostatic model assessment (HOMA) was used to assess insulin sensitivity/resistance. Results Individuals with ≥25 % body fat demonstrated increased PChS-SBP (p < 0.01), but unchanged PChS-MV and PChS-HR (both p > 0.4). PChS-SBP was related positively with anthropometric characteristics (e.g. waist circumference, fat %), plasma insulin and HOMA (all p < 0.05), and negatively with BRS-Seq (p = 0.001), but not with plasma leptin (p = 0.27). Conclusions In healthy men, overweight/obesity is accompanied by augmented blood pressure response from peripheral chemoreceptors, while respiratory and heart rate responses remain unaltered. Hyperinsulinaemia and insulin resistance (but not hyperleptinaemia) are associated with augmented pressure response from chemoreceptors. Electronic supplementary material The online version of this article (doi:10.1007/s10286-015-0338-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bartłomiej Paleczny
- Department of Physiology, Wroclaw Medical University, ul. Chałubińskiego 10, 50-368, Wroclaw, Poland. .,Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland.
| | - Agnieszka Siennicka
- Department of Physiology, Wroclaw Medical University, ul. Chałubińskiego 10, 50-368, Wroclaw, Poland.,Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland
| | - Maciej Zacharski
- Department of Biochemistry, Pharmacology and Toxicology, Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland
| | - Ewa Anita Jankowska
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland.,Laboratory for Applied Research on Cardiovascular System, Department of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
| | - Beata Ponikowska
- Department of Physiology, Wroclaw Medical University, ul. Chałubińskiego 10, 50-368, Wroclaw, Poland
| | - Piotr Ponikowski
- Department of Cardiology, Centre for Heart Diseases, 4th Military Hospital, Wroclaw, Poland.,Department of Heart Diseases, Wroclaw Medical University, Wroclaw, Poland
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33
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Effects of angiotensin II on leptin and downstream leptin signaling in the carotid body during acute intermittent hypoxia. Neuroscience 2015; 310:430-41. [DOI: 10.1016/j.neuroscience.2015.09.066] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 08/11/2015] [Accepted: 09/24/2015] [Indexed: 11/19/2022]
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Bassi M, Furuya WI, Zoccal DB, Menani JV, Colombari E, Hall JE, da Silva AA, do Carmo JM, Colombari DSA. Control of respiratory and cardiovascular functions by leptin. Life Sci 2015; 125:25-31. [PMID: 25645056 PMCID: PMC4355938 DOI: 10.1016/j.lfs.2015.01.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 12/19/2014] [Accepted: 01/23/2015] [Indexed: 01/29/2023]
Abstract
Leptin, a peptide hormone produced by adipose tissue, acts in brain centers that control critical physiological functions such as metabolism, breathing and cardiovascular regulation. The importance of leptin for respiratory control is evident by the fact that leptin deficient mice exhibit impaired ventilatory responses to carbon dioxide (CO2), which can be corrected by intracerebroventricular leptin replacement therapy. Leptin is also recognized as an important link between obesity and hypertension. Humans and animal models lacking either leptin or functional leptin receptors exhibit many characteristics of the metabolic syndrome, including hyperinsulinemia, insulin resistance, hyperglycemia, dyslipidemia and visceral adiposity, but do not exhibit increased sympathetic nerve activity (SNA) and have normal to lower blood pressure (BP) compared to lean controls. Even though previous studies have extensively focused on the brain sites and intracellular signaling pathways involved in leptin effects on food intake and energy balance, the mechanisms that mediate the actions of leptin on breathing and cardiovascular function are only beginning to be elucidated. This mini-review summarizes recent advances on the effects of leptin on cardiovascular and respiratory control with emphasis on the neural control of respiratory function and autonomic activity.
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Affiliation(s)
- M Bassi
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil.
| | - W I Furuya
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - D B Zoccal
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - J V Menani
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - E Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
| | - J E Hall
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
| | - A A da Silva
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
| | - J M do Carmo
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA
| | - D S A Colombari
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University (UNESP), Araraquara, SP, Brazil
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35
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Tissue Dynamics of the Carotid Body Under Chronic Hypoxia: A Computational Study. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 860:25-39. [DOI: 10.1007/978-3-319-18440-1_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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36
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The Carotid Body Does Not Mediate the Acute Ventilatory Effects of Leptin. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 860:379-85. [DOI: 10.1007/978-3-319-18440-1_43] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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37
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Shirahata M, Tang WY, Shin MK, Polotsky VY. Is the Carotid Body a Metabolic Monitor? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 860:153-9. [PMID: 26303477 PMCID: PMC4793901 DOI: 10.1007/978-3-319-18440-1_17] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The carotid body is a multi-modal sensor and it has been debated if it senses low glucose. We have hypothesized that the carotid body is modified by some metabolic factors other than glucose and contributes to whole body glucose metabolism. This study examined the roles of insulin, leptin and transient receptor potential (TRP) channels on carotid sinus nerve (CSN) chemoreceptor discharge. In agreement with other studies, CSN activity was not modified by low glucose. Insulin did not affect the CSN hypoxic response. Leptin significantly augmented the CSN response to hypoxia and nonspecific Trp channel blockers (SKF96365, 2-APB) reversed the effect of leptin. Gene expression analysis showed high expression of Trpm3, 6, and 7 channels in the carotid body and petrosal ganglion. The results suggest that the adult mouse carotid body does not sense glucose levels directly. The carotid body may contribute to neural control of glucose metabolism via leptin receptor-mediated TRP channel activation.
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Affiliation(s)
- M Shirahata
- Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, MD, USA,
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38
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Pye RL, Dunn EJ, Ricker EM, Jurcsisn JG, Barr BL, Wyatt CN. Acutely Administered Leptin Increases [Ca2+] i and BK Ca Currents But Does Not Alter Chemosensory Behavior in Rat Carotid Body Type I Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 860:61-7. [PMID: 26303468 DOI: 10.1007/978-3-319-18440-1_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Obesity related pathologies are the health care crisis of our generation. The fat cell derived adipokine leptin has been shown to be a central stimulant of respiration. Very high levels of leptin, however, are associated with the depressed ventilatory phenotype observed in obesity hypoventilation syndrome. Leptin receptors have been identified on carotid body type I cells but how their activation might influence the physiology of these cells is not known.The acute application of leptin evoked calcium signaling responses in isolated type I cells. Cells increased their Fura 2 ratio by 0.074 ± 0.010 ratio units (n = 39, P < 0.001). Leptin also increased the peak membrane currents in 6 of 9 cells increasing the peak macroscopic currents at +10 mV by 61 ± 14 % (p < 0.02). Leptin administered in the presence of the selective BK(Ca) channel inhibitor Paxilline (0.5 μM) failed to increase membrane currents (n = 5). Interestingly, leptin did not significantly alter the resting membrane potential of isolated type I cells (n = 9) and anoxic/acidic depolarizations were unaffected by leptin (n = 7, n = 6).These data suggest that leptin receptors are functional in type I cells but that their acute activation does not alter chemosensory properties. Future studies will use chronic models of leptin dysregulation.
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Affiliation(s)
- Richard L Pye
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH, 45435, USA
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Guidolin D, Porzionato A, Tortorella C, Macchi V, De Caro R. Fractal analysis of the structural complexity of the connective tissue in human carotid bodies. Front Physiol 2014; 5:432. [PMID: 25414672 PMCID: PMC4220644 DOI: 10.3389/fphys.2014.00432] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 10/17/2014] [Indexed: 12/20/2022] Open
Abstract
The carotid body (CB) may undergo different structural changes during perinatal development, aging, or in response to environmental stimuli. In the previous literature, morphometric approaches to evaluate these changes have considered quantitative first order parameters, such as volumes or densities, while changes in spatial disposition and/or complexity of structural components have not yet been considered. In the present study, different strategies for addressing morphological complexity of CB, apart from the overall amount of each tissue component, were evaluated and compared. In particular, we considered the spatial distribution of connective tissue in the carotid bodies of young control subjects, young opiate-related deaths and aged subjects, through analysis of dispersion (Morisita's index), gray level co-occurrence matrix (entropy, angular second moment, variance, correlation), and fractal analysis (fractal dimension, lacunarity). Opiate-related deaths and aged subjects showed a comparable increase in connective tissue with respect to young controls. However, the Morisita's index (p < 0.05), angular second moment (p < 0.05), fractal dimension (p < 0.01), and lacunarity (p < 0.01) permitted to identify significant differences in the disposition of the connective tissue between these two series. A receiver operating characteristic (ROC) curve was also calculated to evaluate the efficiency of each parameter. The fractal dimension and lacunarity, with areas under the ROC curve of 0.9651 (excellent accuracy) and 0.8835 (good accuracy), respectively, showed the highest discriminatory power. They evidenced higher level of structural complexity in the carotid bodies of opiate-related deaths than old controls, due to more complex branching of intralobular connective tissue. Further analyses will have to consider the suitability of these approaches to address other morphological features of the CB, such as different cell populations, vascularization, and innervation.
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Affiliation(s)
- Diego Guidolin
- Section of Human Anatomy, Department of Molecular Medicine, University of Padova Padova, Italy
| | - Andrea Porzionato
- Section of Human Anatomy, Department of Molecular Medicine, University of Padova Padova, Italy
| | - Cinzia Tortorella
- Section of Human Anatomy, Department of Molecular Medicine, University of Padova Padova, Italy
| | - Veronica Macchi
- Section of Human Anatomy, Department of Molecular Medicine, University of Padova Padova, Italy
| | - Raffaele De Caro
- Section of Human Anatomy, Department of Molecular Medicine, University of Padova Padova, Italy
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Ciriello J, Caverson MM. Carotid chemoreceptor afferent projections to leptin receptor containing neurons in nucleus of the solitary tract. Peptides 2014; 58:30-5. [PMID: 24905621 DOI: 10.1016/j.peptides.2014.05.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/26/2014] [Accepted: 05/27/2014] [Indexed: 11/23/2022]
Abstract
Neurons expressing the leptin receptor (Ob-R) exist within the caudal nucleus of the solitary tract (NTS). Additionally, afferent neurons expressing the Ob-R have been identified within the nodose ganglion and NTS. Furthermore, systemic injections or focal injections of leptin directly into NTS potentiate the response of NTS neurons to carotid chemoreceptor activation. However, the distribution of carotid body afferents in relation to Ob-R containing neurons within NTS is not known. In this study, chemoreceptor afferent fibers were labeled following microinjection of the anterograde tract tracer biotinylated dextran amine (BDA) into the carotid body or petrosal/nodose ganglion of Wistar rats. After a survival period of 10-14 days, the NTS was processed for BDA and Ob-R immunoreactivity. Afferent axons originating in the carotid body were found to project to the lateral (Slt), gelantinosa (Sg), and medial (Sm) subnuclei of the NTS complex. A similar, but more robust distribution of BDA labeled fibers was observed in the NTS complex after injections into the petrosal/nodose ganglion. Carotid body BDA labeled fibers were observed in close apposition to Ob-R immunoreactive neurons in the region of Slt, Sg and Sm. In addition, a small number of carotid body afferents were found to contain both BDA and express Ob-R-like immunoreactivity within the regions of Slt, Sg and Sm. Taken together, these data suggest that leptin may modulate carotid chemoreceptor function not only through direct effects on NTS neurons, but also through a direct effect on carotid body primary afferent fibers that innervate NTS neurons.
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Affiliation(s)
- John Ciriello
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada N6A 5C1.
| | - Monica M Caverson
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada N6A 5C1
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Dam J, Jockers R. Hunting for the functions of short leptin receptor isoforms. Mol Metab 2013; 2:327-8. [PMID: 24327948 DOI: 10.1016/j.molmet.2013.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 09/06/2013] [Indexed: 11/30/2022] Open
Affiliation(s)
- Julie Dam
- Inserm, U1016, Institut Cochin, Paris, France ; CNRS UMR 8104, Paris, France ; Univ. Paris Descartes, Sorbonne Paris Cite, Paris, France
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Li Z, Ceccarini G, Eisenstein M, Tan K, Friedman JM. Phenotypic effects of an induced mutation of the ObRa isoform of the leptin receptor. Mol Metab 2013; 2:364-75. [PMID: 24327953 DOI: 10.1016/j.molmet.2013.07.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 12/14/2022] Open
Abstract
Leptin receptors play critical roles in mediating leptin's pleiotropic effects on mammalian physiology. To date, six splice variants of the leptin receptor gene have been identified [1-3]. These splice variants have identical extracellular leptin binding motifs but different intracellular C termini. The finding that mutations specifically ablating the function of ObRb cause obesity has established a critical role for this isoform in leptin signaling [1,7]. ObRa is the most abundant splicing isoform with a broad tissue distribution [5], and it has been proposed to play roles in regulating leptin bioavailability, CSF (cerebrospinal fluid) transport and function by forming heterodimers with ObRb and also activating signal transduction via JAK2 in-vitro [5-10]. To assess the in-vivo role of ObRa, we generated an ObRa KO mouse by deleting the ObRa-specific exon 19a. Homozygous mutant mice breed normally and are indistinguishable from wild-type mice on regular chow diet, but show a slightly increased basal plasma leptin, a slight improvement of their GTT and a slightly reduced response to systemic leptin administration. These mice also show a modest but statistically significant increase in weight when placed on a high fat diet with a slightly reduced CSF/plasma ratio of leptin. These data suggest that ObRa plays a role in mediating some of leptin's effects but that the phenotypic consequences are modest compared to a deletion of ObRb.
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Affiliation(s)
- Zhiying Li
- The Rockefeller University, 1230 York Avenue, NY 10065, USA
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Messenger SA, Moreau JM, Ciriello J. Effect of chronic intermittent hypoxia on leptin and leptin receptor protein expression in the carotid body. Brain Res 2013; 1513:51-60. [DOI: 10.1016/j.brainres.2013.03.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 03/18/2013] [Accepted: 03/20/2013] [Indexed: 01/20/2023]
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Porzionato A, Macchi V, De Caro R. Role of the carotid body in obesity-related sympathoactivation. Hypertension 2013; 61:e57. [PMID: 23648701 DOI: 10.1161/hypertensionaha.113.01248] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Porzionato A, Macchi V, De Caro R, Di Giulio C. Inflammatory and immunomodulatory mechanisms in the carotid body. Respir Physiol Neurobiol 2013; 187:31-40. [PMID: 23485800 DOI: 10.1016/j.resp.2013.02.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Revised: 02/05/2013] [Accepted: 02/19/2013] [Indexed: 10/27/2022]
Abstract
Evidence is available about the role of inflammatory/immunological factors in the physiology and plasticity of the carotid body, with potential clinical implications in obstructive sleep apnea syndrome and sudden infant death syndrome. In humans, lymphomonocytic aggregations (chronic carotid glomitis) have been reported in aging and opiate addiction. Glomus cells produce prostaglandin E2 and the cytokines interleukin 1β, interleukin 6 and TNF-α, with corresponding receptors. These factors modulate glomus cell excitability, catecholamine release and/or chemoreceptor discharge. The above cytokines are up-regulated in chronic sustained or intermittent hypoxia, and prevention of these changes, with ibuprofen or dexamethasone, may modulate hypoxia-induced changes in carotid body chemosensitivity. The main transcription factors considered to be involved are NF-kB and HIFs. Circulating immunogens (lipopolysaccharide) and cytokines may also affect peripheral arterial chemoreception, with the carotid body exerting an immunosensing function.
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Affiliation(s)
- Andrea Porzionato
- Section of Anatomy, Department of Molecular Medicine, University of Padova, Padova, Italy.
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De Caro R, Macchi V, Sfriso MM, Porzionato A. Structural and neurochemical changes in the maturation of the carotid body. Respir Physiol Neurobiol 2013; 185:9-19. [DOI: 10.1016/j.resp.2012.06.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 05/16/2012] [Accepted: 06/08/2012] [Indexed: 02/07/2023]
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Abstract
Glomus cells in the carotid body are responsible for detecting changes in the partial pressure of blood oxygen (PO₂). These glomus cells have recently been found to express leptin receptors and are activated by intermittent hypoxia (IH) and systemic leptin injections, although the function of leptin within the carotid body remains unknown. The present study was done to investigate whether IH activates leptin signalling pathways within leptin-expressing carotid body glomus cells. Rats were subjected to IH (120-s normoxia, 80-s hypoxia for 8 h) or normoxia (8 h). Exposure to IH increased plasma leptin levels almost sixfold compared to normoxic controls. Additionally, IH was found to increase leptin, ERK1/2 and Fra-1/2 immunoreactivity within glomus cells. Systemic leptin injections evoked similar effects on leptin, ERK1/2 and Fra-1/2 immunoreactivity within the glomus cells. Furthermore, using Western blot analysis, IH was found to increase protein expression of leptin, the short form of the leptin receptor (Ob-R₁₀₀ kDa) and suppressor of cytokine signalling 3. On the other hand, IH induced a decrease in long form of leptin receptors (Ob-Rb) protein expression. Taken together, these data suggest that the increased levels of leptin within the circulation and those within the glomus cells induced by IH may alter carotid bodies chemosensitivity to hypoxic stimuli.
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Affiliation(s)
- S A Messenger
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada N6A 5C1
| | - J Ciriello
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada N6A 5C1.
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Bassi M, Giusti H, Leite CM, Anselmo-Franci JA, do Carmo JM, da Silva AA, Hall JE, Colombari E, Glass ML. Central leptin replacement enhances chemorespiratory responses in leptin-deficient mice independent of changes in body weight. Pflugers Arch 2012; 464:145-53. [PMID: 22585210 DOI: 10.1007/s00424-012-1111-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 04/13/2012] [Accepted: 04/23/2012] [Indexed: 12/11/2022]
Abstract
Previous studies showed that leptin-deficient (ob/ob) mice develop obesity and impaired ventilatory responses to CO(2) (V(E) - CO(2)). In this study, we examined if leptin replacement improves chemorespiratory responses to hypercapnia (7 % CO(2)) in ob/ob mice and if these effects were due to changes in body weight or to the direct effects of leptin in the central nervous system (CNS). V(E) - CO(2) was measured via plethysmography in obese leptin-deficient- (ob/ob) and wild-type- (WT) mice before and after leptin (10 μg/2 μl day) or vehicle (phosphate buffer solution) were microinjected into the fourth ventricle for four consecutive days. Although baseline V(E) was similar between groups, obese ob/ob mice exhibited attenuated V(E) - CO(2) compared to WT mice (134 ± 9 versus 196 ± 10 ml min(-1)). Fourth ventricle leptin treatment in obese ob/ob mice significantly improved V(E) - CO(2) (from 131 ± 15 to 197 ± 10 ml min(-1)) by increasing tidal volume (from 0.38 ± 0.03 to 0.55 ± 0.02 ml, vehicle and leptin, respectively). Subcutaneous leptin administration at the same dose administered centrally did not change V(E) - CO(2) in ob/ob mice. Central leptin treatment in WT had no effect on V(E) - CO(2). Since the fourth ventricle leptin treatment decreased body weight in ob/ob mice, we also examined V(E) - CO(2) in lean pair-weighted ob/ob mice and found it to be impaired compared to WT mice. Thus, leptin deficiency, rather than obesity, is the main cause of impaired V(E) - CO(2) in ob/ob mice and leptin appears to play an important role in regulating chemorespiratory response by its direct actions on the CNS.
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Affiliation(s)
- Mirian Bassi
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, 1680 Humaita St. Araraquara, São Paulo, Brazil.
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Intermittent hypoxia and systemic leptin administration induces pSTAT3 and Fos/Fra-1 in the carotid body. Brain Res 2012; 1446:56-70. [DOI: 10.1016/j.brainres.2012.01.074] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 01/19/2012] [Accepted: 01/28/2012] [Indexed: 12/16/2022]
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Porzionato A, Fenu G, Rucinski M, Macchi V, Montella A, Malendowicz LK, De Caro R. KISS1 and KISS1R expression in the human and rat carotid body and superior cervical ganglion. Eur J Histochem 2011; 55:e14. [PMID: 22193294 PMCID: PMC3284150 DOI: 10.4081/ejh.2011.e14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Revised: 03/21/2011] [Accepted: 03/22/2011] [Indexed: 12/28/2022] Open
Abstract
KISS1 and its receptor, KISS1R, have both been found to be expressed in central nervous system, but few data are present in the literature about their distribution in peripheral nervous structures. Thus, the aim of the present study was to investigate, through immunohistochemistry, the expression and distribution of KISS1 and KISS1R in the rat and human carotid bodies and superior cervical ganglia, also with particular reference to the different cellular populations. Materials consisted of carotid bodies and superior cervical ganglia were obtained at autopsy from 10 adult subjects and sampled from 10 adult Sprague-Dawley rats. Immunohistochemistry revealed diffuse expression of KISS1 and KISS1R in type I cells of both human and rat carotid bodies, whereas type II cells were negative. In both human and rat superior cervical ganglia positive anti-KISS1 and -KISS1R immunostainings were also selectively found in ganglion cells, satellite cells being negative. Endothelial cells also showed moderate immunostaining for both KISS1 and KISS1R. The expression of both kisspeptins and kisspeptin receptors in glomic type I cells and sympathetic ganglion cells supports a modulatory role of KISS1 on peripheral chemoreception and sympathetic function. Moreover, local changes in blood flow have been considered to be involved in carotid body chemoreceptor discharge and kisspeptins and kisspeptin receptors have also been found in the endothelial cells. As a consequence, a possible role of kisspeptins in the regulation of carotid body blood flow and, indirectly, in chemoreceptor discharge may also be hypothesized.
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Affiliation(s)
- A Porzionato
- Section of Anatomy, Department of Human Anatomy and Physiology, University of Padova, Italy
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