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Matthews RM, Bradley E, Hollywood MA, Lundy FT, McGarvey LP, Sergeant GP, Thornbury KD. Modulation of fast sodium current in airway smooth muscle cells by exchange protein directly activated by cAMP. Am J Physiol Cell Physiol 2024; 326:C1-C9. [PMID: 37955124 PMCID: PMC11192474 DOI: 10.1152/ajpcell.00417.2023] [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] [Received: 08/31/2023] [Revised: 10/19/2023] [Accepted: 11/01/2023] [Indexed: 11/14/2023]
Abstract
Airway smooth muscle (ASM) cells from mouse bronchus express a fast sodium current mediated by NaV1.7. We present evidence that this current is regulated by cAMP. ASM cells were isolated by enzymatic dispersal and studied using the whole cell patch clamp technique at room temperature. A fast sodium current, INa, was observed on holding cells under voltage clamp at -100 mV and stepping to -20 mV. This current was reduced in a concentration-dependent manner by denopamine (10 and 30 µM), a β-adrenergic agonist. Forskolin (1 µM), an activator of adenylate cyclase, reduced the current by 35%, but 6-MB-cAMP (300 µM), an activator of protein kinase A (PKA), had no effect. In contrast, 8-pCPT-2-O-Me-cAMP-AM (007-AM, 10 µM), an activator of exchange protein directly activated by cAMP (Epac), reduced the current by 48%. The inhibitory effect of 007-AM was still observed in the presence of dantrolene (10 µM), an inhibitor of ryanodine receptors, and when cytosolic [Ca2+] was buffered by inclusion of 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, Sigma (BAPTA) (50 µM) in the pipette solution, suggesting that the inhibition of INa was not due to Ca2+-release from intracellular stores. When 007-AM was tested on the current-voltage relationship, it reduced the current at potentials from -30 to 0 mV, but had no effect on the steady-state activation curve. However, the steady-state inactivation V1/2, the voltage causing inactivation of 50% of the current, was shifted in the negative direction from -76.6 mV to -89.7 mV. These findings suggest that cAMP regulates INa in mouse ASM via Epac, but not PKA.NEW & NOTEWORTHY β-adrenergic agonists are commonly used in inhalers to treat asthma and chronic obstructive pulmonary disease. These work by causing bronchodilation and reducing inflammation. The present study provides evidence that these drugs have an additional action, namely, to reduce sodium influx into airway smooth muscle cells via fast voltage-dependent channels. This may have the dual effect of promoting bronchodilation and reducing remodeling of the airways, which has a detrimental effect in these diseases.
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Affiliation(s)
- Ruth M. Matthews
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Eamonn Bradley
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Mark A. Hollywood
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Fionnuala T. Lundy
- School of Medicine, Dentistry and Biomedical Sciences, Wellcome Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Lorcan P. McGarvey
- School of Medicine, Dentistry and Biomedical Sciences, Wellcome Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom
| | - Gerard P. Sergeant
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Keith D. Thornbury
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
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2
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Hernández-Plata E, Cruz AA, Becerril C. Na V1.7 channels are expressed in the lower airways of the human respiratory tract. Respir Physiol Neurobiol 2023; 311:104034. [PMID: 36792043 DOI: 10.1016/j.resp.2023.104034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/01/2023] [Accepted: 02/12/2023] [Indexed: 02/17/2023]
Abstract
NaV channels expression have been reported in upper airways and tracheal smooth muscle cells controlling the generation and propagation of action potentials in the respiratory tract sensory neurons, but information about the presence of these proteins in the bronchioalveolar structures in human lungs was missing. The main objective covered in this work was to determine whether the NaV1.7 channels are expressed in lower airways, and to identify the cellular identities expressing these proteins. We detected high levels of the mRNA coding for NaV1.7 channels in isolated lung fibroblasts obtained from both normal lungs, and fibrotic lungs of patients with respiratory diseases. The protein was detected with two different antibodies in the bronchioalveolar tissue, alveolar endothelium, and capillary endothelium, in normal and pathologic lungs. These evidences are useful in the dissection of molecular mechanisms of pulmonary pathologies, and lead to consider the NaV1.7 channels as potential therapeutic targets for the treatment of pulmonary diseases.
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Affiliation(s)
- Everardo Hernández-Plata
- Investigador por México, Consejo Nacional de Ciencia y Tecnología, and Instituto Nacional de Medicina Genómica, Mexico City, Mexico.
| | - Ana Alfaro Cruz
- Departamento de Patología, Hospital General de México, "Dr. Eduardo Liceaga", Mexico City, Mexico
| | - Carina Becerril
- Instituto Nacional de Enfermedades Respiratorias "Ismael Cosío Villegas", Mexico City, Mexico
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3
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Romero-Martínez BS, Sommer B, Solís-Chagoyán H, Calixto E, Aquino-Gálvez A, Jaimez R, Gomez-Verjan JC, González-Avila G, Flores-Soto E, Montaño LM. Estrogenic Modulation of Ionic Channels, Pumps and Exchangers in Airway Smooth Muscle. Int J Mol Sci 2023; 24:ijms24097879. [PMID: 37175587 PMCID: PMC10178541 DOI: 10.3390/ijms24097879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 02/28/2023] [Accepted: 02/28/2023] [Indexed: 05/15/2023] Open
Abstract
To preserve ionic homeostasis (primarily Ca2+, K+, Na+, and Cl-), in the airway smooth muscle (ASM) numerous transporters (channels, exchangers, and pumps) regulate the influx and efflux of these ions. Many of intracellular processes depend on continuous ionic permeation, including exocytosis, contraction, metabolism, transcription, fecundation, proliferation, and apoptosis. These mechanisms are precisely regulated, for instance, through hormonal activity. The lipophilic nature of steroidal hormones allows their free transit into the cell where, in most cases, they occupy their cognate receptor to generate genomic actions. In the sense, estrogens can stimulate development, proliferation, migration, and survival of target cells, including in lung physiology. Non-genomic actions on the other hand do not imply estrogen's intracellular receptor occupation, nor do they initiate transcription and are mostly immediate to the stimulus. Among estrogen's non genomic responses regulation of calcium homeostasis and contraction and relaxation processes play paramount roles in ASM. On the other hand, disruption of calcium homeostasis has been closely associated with some ASM pathological mechanism. Thus, this paper intends to summarize the effects of estrogen on ionic handling proteins in ASM. The considerable diversity, range and power of estrogens regulates ionic homeostasis through genomic and non-genomic mechanisms.
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Affiliation(s)
- Bianca S Romero-Martínez
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Bettina Sommer
- Laboratorio de Hiperreactividad Bronquial, Instituto Nacional de Enfermedades Respiratorias "Ismael Cosío Villegas", Ciudad de México 14080, Mexico
| | - Héctor Solís-Chagoyán
- Neurociencia Cognitiva Evolutiva, Centro de Investigación en Ciencias Cognitivas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico
| | - Eduardo Calixto
- Departamento de Neurobiología, Dirección de Investigación en Neurociencias, Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñiz", Ciudad de México 14370, Mexico
| | - Arnoldo Aquino-Gálvez
- Laboratorio de Biología Molecular, Departamento de Fibrosis Pulmonar, Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, México City 14080, Mexico
| | - Ruth Jaimez
- Laboratorio de Estrógenos y Hemostasis, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Juan C Gomez-Verjan
- Dirección de Investigación, Instituto Nacional de Geriatría (INGER), Ciudad de México 10200, Mexico
| | - Georgina González-Avila
- Laboratorio de Oncología Biomédica, Instituto Nacional de Enfermedades Respiratorias "Ismael Cosío Villegas", México City 14080, Mexico
| | - Edgar Flores-Soto
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Luis M Montaño
- Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
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4
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Matthews RM, Bradley E, Griffin CS, Lim XR, Mullins ND, Hollywood MA, Lundy FT, McGarvey LP, Sergeant GP, Thornbury KD. Functional expression of Na V1.7 channels in freshly dispersed mouse bronchial smooth muscle cells. Am J Physiol Cell Physiol 2022; 323:C749-C762. [DOI: 10.1152/ajpcell.00011.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Isolated smooth muscle cells (SMC) from mouse bronchus were studied using the whole-cell patch clamp technique at ~21oC. Stepping from -100 mV to -20 mV evoked inward currents of mean amplitude -275 pA. These inactivated (tau=1.1 ms) and were abolished when external Na+ was substituted with N-Methyl-D-glucamine. In current-voltage protocols, current peaked at -10 mV and reversed between +20 and +30 mV. The V1/2s of activation and inactivation were -25 & -86 mV, respectively. The current was highly sensitive to tetrodotoxin (IC50=1.5 nM) and the NaV1.7 subtype selective blocker, PF-05089771 (IC50=8.6 nM), consistent with NaV1.7 as the underlying pore-forming a subunit. Two NaV1.7-selective antibodies caused membrane-delineated staining of isolated SMC, as did a non-selective pan-NaVantibody. RT-PCR, performed on groups of ~15 isolated SMC, revealed transcripts for NaV1.7 in 7/8 samples. Veratridine (30 mM), a non-selective NaV channel activator, reduced peak current evoked by depolarization but induced a sustained current of 40 pA. Both effects were reversed by tetrodotoxin (100 nM). In tension experiments veratridine (10 mM) induced contractions that were entirely blocked by atropine (1 mM). However, in the presence of atropine, veratridine was able to modulate the pattern of activity induced by a combination of U-46619 (a thromboxane A2 mimetic) & PGE2(prostaglandin E2), by eliminating bursts in favour of sustained phasic contractions. These effects were readily reversed to control-like activity by tetrodotoxin (100 nM). In conclusion, mouse bronchial SMC functionally express NaV1.7 channels that are capable of modulating contractile activity, at least under experimental conditions.
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Affiliation(s)
- Ruth M. Matthews
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, County Louth, Ireland
| | - Eamonn Bradley
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, County Louth, Ireland
| | - Caoimhin S. Griffin
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, County Louth, Ireland
| | - Xin Rui Lim
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, County Louth, Ireland
| | - Nicolas D. Mullins
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, County Louth, Ireland
| | - Mark A. Hollywood
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, County Louth, Ireland
| | - Fionnuala T. Lundy
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, County Louth, Ireland
| | - Lorcan P. McGarvey
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, County Louth, Ireland
| | - Gerard P. Sergeant
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, County Louth, Ireland
| | - Keith D. Thornbury
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, County Louth, Ireland
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5
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Fouda MA, Ghovanloo MR, Ruben PC. Late sodium current: incomplete inactivation triggers seizures, myotonias, arrhythmias, and pain syndromes. J Physiol 2022; 600:2835-2851. [PMID: 35436004 DOI: 10.1113/jp282768] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/12/2022] [Indexed: 11/08/2022] Open
Abstract
Acquired and inherited dysfunction in voltage-gated sodium channels underlies a wide range of diseases. "In addition to the defects in trafficking and expression, sodium channelopathies are also caused by dysfunction in one or several gating properties, for instance activation or inactivation. Disruption of the channel inactivation leads to the increased late sodium current, which is a common defect in seizure disorders, cardiac arrhythmias skeletal muscle myotonia and pain. An increase in late sodium current leads to repetitive action potential in neurons and skeletal muscles, and prolonged action potential duration in the heart. In this topical review, we compare the effects of late sodium current in brain, heart, skeletal muscle, and peripheral nerves. Abstract figure legend Shows cartoon illustration of general Nav channel transitions between (1) resting, (2) open, and (3) fast inactivated states. Disruption of the inactivation process exacerbates (4) late sodium currents. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mohamed A Fouda
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada.,Department of Pharmacology and Toxicology, Alexandria University, Alexandria, Egypt
| | | | - Peter C Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
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6
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Ranolazine: An Old Drug with Emerging Potential; Lessons from Pre-Clinical and Clinical Investigations for Possible Repositioning. Pharmaceuticals (Basel) 2021; 15:ph15010031. [PMID: 35056088 PMCID: PMC8777683 DOI: 10.3390/ph15010031] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/16/2021] [Accepted: 12/20/2021] [Indexed: 02/07/2023] Open
Abstract
Ischemic heart disease is a significant public health problem with high mortality and morbidity. Extensive scientific investigations from basic sciences to clinics revealed multilevel alterations from metabolic imbalance, altered electrophysiology, and defective Ca2+/Na+ homeostasis leading to lethal arrhythmias. Despite the recent identification of numerous molecular targets with potential therapeutic interest, a pragmatic observation on the current pharmacological R&D output confirms the lack of new therapeutic offers to patients. By contrast, from recent trials, molecules initially developed for other fields of application have shown cardiovascular benefits, as illustrated with some anti-diabetic agents, regardless of the presence or absence of diabetes, emphasizing the clear advantage of “old” drug repositioning. Ranolazine is approved as an antianginal agent and has a favorable overall safety profile. This drug, developed initially as a metabolic modulator, was also identified as an inhibitor of the cardiac late Na+ current, although it also blocks other ionic currents, including the hERG/Ikr K+ current. The latter actions have been involved in this drug’s antiarrhythmic effects, both on supraventricular and ventricular arrhythmias (VA). However, despite initial enthusiasm and promising development in the cardiovascular field, ranolazine is only authorized as a second-line treatment in patients with chronic angina pectoris, notwithstanding its antiarrhythmic properties. A plausible reason for this is the apparent difficulty in linking the clinical benefits to the multiple molecular actions of this drug. Here, we review ranolazine’s experimental and clinical knowledge on cardiac metabolism and arrhythmias. We also highlight advances in understanding novel effects on neurons, the vascular system, skeletal muscles, blood sugar control, and cancer, which may open the way to reposition this “old” drug alone or in combination with other medications.
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7
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The Changes in Expression of Na V1.7 and Na V1.8 and the Effects of the Inhalation of Their Blockers in Healthy and Ovalbumin-Sensitized Guinea Pig Airways. MEMBRANES 2021; 11:membranes11070511. [PMID: 34357161 PMCID: PMC8304019 DOI: 10.3390/membranes11070511] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 07/01/2021] [Accepted: 07/03/2021] [Indexed: 01/06/2023]
Abstract
Background: The presented study evaluated the suppositional changes in the airway expression of Nav1.8 and Nav1.7 and their role in the airway defense mechanisms in healthy animals and in an experimental asthma model. Methods: The effects of the blockers inhalation on the reactivity of guinea pig airways, number of citric-acid-induced coughs and ciliary beating frequency (CBF) were tested in vivo. Chronic inflammation simulating asthma was induced by repetitive exposure to ovalbumin. The expression of Nav1.7 and Nav1.8 was examined by ELISA. Results: The Nav 1.8 blocker showed complex antitussive and bronchodilatory effects and significantly regulated the CBF in healthy and sensitized animals. The Nav1.7 blockers significantly inhibited coughing and participated in CBF control in the ovalbumin-sensitized animals. The increased expression of the respective ion channels in the sensitized animals corresponded to changes in CBF regulation. The therapeutic potency of the Nav1.8 blocker was evidenced in combinations with classic bronchodilators. Conclusion: The allergic-inflammation-upregulated expression of Nav1.7 and Nav1.8 and corresponding effects of blocker inhalation on airway defense mechanisms, along with the Nav1.8 blocker’s compatibility with classic antiasthmatic drugs, bring novel possibilities for the treatment of various respiratory diseases. However, the influence of the Nav1.8 blocker on CBF requires further investigation.
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8
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Nathan S, Gabelli SB, Yoder JB, Srinivasan L, Aldrich RW, Tomaselli GF, Ben-Johny M, Amzel LM. Structural basis of cytoplasmic NaV1.5 and NaV1.4 regulation. J Gen Physiol 2020; 153:211587. [PMID: 33306788 PMCID: PMC7953540 DOI: 10.1085/jgp.202012722] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/06/2020] [Indexed: 12/14/2022] Open
Abstract
Voltage-gated sodium channels (NaVs) are membrane proteins responsible for the rapid upstroke of the action potential in excitable cells. There are nine human voltage-sensitive NaV1 isoforms that, in addition to their sequence differences, differ in tissue distribution and specific function. This review focuses on isoforms NaV1.4 and NaV1.5, which are primarily expressed in skeletal and cardiac muscle cells, respectively. The determination of the structures of several eukaryotic NaVs by single-particle cryo-electron microscopy (cryo-EM) has brought new perspective to the study of the channels. Alignment of the cryo-EM structure of the transmembrane channel pore with x-ray crystallographic structures of the cytoplasmic domains illustrates the complementary nature of the techniques and highlights the intricate cellular mechanisms that modulate these channels. Here, we review structural insights into the cytoplasmic C-terminal regulation of NaV1.4 and NaV1.5 with special attention to Ca2+ sensing by calmodulin, implications for disease, and putative channel dimerization.
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Affiliation(s)
- Sara Nathan
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Sandra B Gabelli
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD.,Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Jesse B Yoder
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Lakshmi Srinivasan
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Richard W Aldrich
- Department of Neuroscience, University of Texas at Austin, Austin, TX
| | - Gordon F Tomaselli
- Division of Cardiology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY
| | - L Mario Amzel
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD.,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD
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9
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Gonçalves TC, Benoit E, Partiseti M, Servent D. The Na V1.7 Channel Subtype as an Antinociceptive Target for Spider Toxins in Adult Dorsal Root Ganglia Neurons. Front Pharmacol 2018; 9:1000. [PMID: 30233376 PMCID: PMC6131673 DOI: 10.3389/fphar.2018.01000] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 08/14/2018] [Indexed: 12/11/2022] Open
Abstract
Although necessary for human survival, pain may sometimes become pathologic if long-lasting and associated with alterations in its signaling pathway. Opioid painkillers are officially used to treat moderate to severe, and even mild, pain. However, the consequent strong and not so rare complications that occur, including addiction and overdose, combined with pain management costs, remain an important societal and economic concern. In this context, animal venom toxins represent an original source of antinociceptive peptides that mainly target ion channels (such as ASICs as well as TRP, CaV, KV and NaV channels) involved in pain transmission. The present review aims to highlight the NaV1.7 channel subtype as an antinociceptive target for spider toxins in adult dorsal root ganglia neurons. It will detail (i) the characteristics of these primary sensory neurons, the first ones in contact with pain stimulus and conveying the nociceptive message, (ii) the electrophysiological properties of the different NaV channel subtypes expressed in these neurons, with a particular attention on the NaV1.7 subtype, an antinociceptive target of choice that has been validated by human genetic evidence, and (iii) the features of spider venom toxins, shaped of inhibitory cysteine knot motif, that present high affinity for the NaV1.7 subtype associated with evidenced analgesic efficacy in animal models.
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Affiliation(s)
- Tânia C Gonçalves
- Sanofi R&D, Integrated Drug Discovery - High Content Biology, Paris, France.,Service d'Ingénierie Moléculaire des Protéines, CEA de Saclay, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Evelyne Benoit
- Service d'Ingénierie Moléculaire des Protéines, CEA de Saclay, Université Paris-Saclay, Gif-sur-Yvette, France.,Institut des Neurosciences Paris-Saclay, UMR CNRS/Université Paris-Sud 9197, Gif-sur-Yvette, France
| | - Michel Partiseti
- Sanofi R&D, Integrated Drug Discovery - High Content Biology, Paris, France
| | - Denis Servent
- Service d'Ingénierie Moléculaire des Protéines, CEA de Saclay, Université Paris-Saclay, Gif-sur-Yvette, France
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10
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Voltage-dependent inward currents in smooth muscle cells of skeletal muscle arterioles. PLoS One 2018; 13:e0194980. [PMID: 29694371 PMCID: PMC5919073 DOI: 10.1371/journal.pone.0194980] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 03/08/2018] [Indexed: 01/14/2023] Open
Abstract
Voltage-dependent inward currents responsible for the depolarizing phase of action potentials were characterized in smooth muscle cells of 4th order arterioles in mouse skeletal muscle. Currents through L-type Ca2+ channels were expected to be dominant; however, action potentials were not eliminated in nominally Ca2+-free bathing solution or by addition of L-type Ca2+ channel blocker nifedipine (10 μM). Instead, Na+ channel blocker tetrodotoxin (TTX, 1 μM) reduced the maximal velocity of the upstroke at low, but not at normal (2 mM), Ca2+ in the bath. The magnitude of TTX-sensitive currents recorded with 140 mM Na+ was about 20 pA/pF. TTX-sensitive currents decreased five-fold when Ca2+ increased from 2 to 10 mM. The currents reduced three-fold in the presence of 10 mM caffeine, but remained unaltered by 1 mM of isobutylmethylxanthine (IBMX). In addition to L-type Ca2+ currents (15 pA/pF in 20 mM Ca2+), we also found Ca2+ currents that are resistant to 10 μM nifedipine (5 pA/pF in 20 mM Ca2+). Based on their biophysical properties, these Ca2+ currents are likely to be through voltage-gated T-type Ca2+ channels. Our results suggest that Na+ and at least two types (T- and L-) of Ca2+ voltage-gated channels contribute to depolarization of smooth muscle cells in skeletal muscle arterioles. Voltage-gated Na+ channels appear to be under a tight control by Ca2+ signaling.
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11
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Abstract
Fever-associated seizures or epilepsy (FASE) is primarily characterised by the occurrence of a seizure or epilepsy usually accompanied by a fever. It is common in infants and children, and generally includes febrile seizures (FS), febrile seizures plus (FS+), Dravet syndrome (DS) and genetic epilepsy with febrile seizures plus (GEFSP). The aetiology of FASE is unclear. Genetic factors may play crucial roles in FASE. Mutations in certain genes may cause a wide spectrum of phenotypical overlap ranging from isolated FS, FS+ and GEFSP to DS. Synapse-associated proteins, postsynaptic GABAA receptor, and sodium channels play important roles in synaptic transmission. Mutations in these genes may involve in the pathogenesis of FASE. Elevated temperature promotes synaptic vesicle (SV) recycling and enlarges SV size, which may enhance synaptic transmission and contribute to FASE occurring. This review provides an overview of the loci, genes, underlying pathogenesis and the fever-inducing effect of FASE. It may provide a more comprehensive understanding of pathogenesis and contribute to the clinical diagnosis of FASE.
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12
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Kocmalova M, Joskova M, Franova S, Banovcin P, Sutovska M. Airway Defense Control Mediated via Voltage-Gated Sodium Channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 921:71-80. [PMID: 27161110 DOI: 10.1007/5584_2016_244] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Expression of voltage-gated sodium channels (Nav) takes place in the airways and the role of Nav1.7 and Nav1.8 in the control of airway's defense reflexes has been confirmed. The activation of Nav channels is crucial for cough initiation and airway smooth muscle reactivity, but it is unknown whether these channels regulate ciliary beating. This study evaluated the involvement of Nav1.7 and Nav1.8 channels in the airway defense mechanisms using their pharmacological blockers in healthy guinea pigs and in the experimental allergic asthma model. Asthma was modeled by ovalbumin sensitization over a period of 21 days. Blockade of Nav1.7 channels significantly decreased airway smooth muscle reactivity in vivo, the number of cough efforts, and the cilia beat frequency in healthy animals. In the allergic asthma model, blockade of Nav1.8 efficiently relieved symptoms of asthma, without adversely affecting cilia beat frequency. The study demonstrates that Nav1.8 channel antagonism has a potential to alleviate cough and bronchial hyperreactivity in asthma.
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Affiliation(s)
- M Kocmalova
- Department of Pharmacology, Division of Respirology, BioMed Martin, Jessenius Faculty of Medicine, Comenius University in Bratislava, 4C Mala Hora St, 036 01, Martin, Slovakia
| | - M Joskova
- Department of Pharmacology, Division of Respirology, BioMed Martin, Jessenius Faculty of Medicine, Comenius University in Bratislava, 4C Mala Hora St, 036 01, Martin, Slovakia.
| | - S Franova
- Department of Pharmacology, Division of Respirology, BioMed Martin, Jessenius Faculty of Medicine, Comenius University in Bratislava, 4C Mala Hora St, 036 01, Martin, Slovakia
| | - P Banovcin
- Department of Children and Adolescents, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, and Martin University Hospital, Martin, Slovakia
| | - M Sutovska
- Department of Pharmacology, Division of Respirology, BioMed Martin, Jessenius Faculty of Medicine, Comenius University in Bratislava, 4C Mala Hora St, 036 01, Martin, Slovakia
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13
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Sommer B, Flores-Soto E, Gonzalez-Avila G. Cellular Na+ handling mechanisms involved in airway smooth muscle contraction (Review). Int J Mol Med 2017; 40:3-9. [PMID: 28534960 PMCID: PMC5466399 DOI: 10.3892/ijmm.2017.2993] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 04/20/2017] [Indexed: 12/17/2022] Open
Abstract
A decrease in bronchial diameter is designated as bronchoconstriction (BC) and impedes the flow of air through the airway. Asthma is characterized by inflammation of the airways, reversible BC and nonspecific hyperreactivity. These last two symptoms are dependent on airway smooth muscle. Stimuli that trigger contraction can be characterized as chemical (neurotransmitters, cytokines and terpenoids) and physical (volume inspired, air pressure). Both stimuli activate signaling pathways by acting on membrane proteins and facilitating the passage of ions through the membrane, generating a voltage change and a subsequent depolarization. Na+ plays an important role in preserving the resting membrane potential; this ion is extracted from the cells by the Na+/K+ ATPase (NKA) or introduced into the cytoplasm by the Na+/Ca2+ exchanger (NCX). During depolarization, Na+ appears to accumulate in specific regions beneath the plasma membrane, generating local concentration gradients which determine the handling of Ca2+. At rest, the smooth muscle has a basal tone that is preserved by the continuous adjustment of intracytoplasmic concentrations of Ca2+ and Na+. At homeostasis, the Na+ concentration is primarily dependent on three structures: the NKA, the NCX and non-specific cation channels (NSCC). These three structures, their functions and the available evidence of the probable role of Na+ in asthma are described in the present review.
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Affiliation(s)
- Bettina Sommer
- Department of Bronchial Hyperreactivity, National Institute of Respiratory Diseases 'Ismael Cosio Villegas', CP 14080 Mexico City, Mexico
| | - Edgar Flores-Soto
- Department of Pharmacology, Faculty of Medicine, National Autonomous University of Mexico, CP 04510 Mexico City, Mexico
| | - Georgina Gonzalez-Avila
- Biomedical Oncology Laboratory, Department of Chronic‑Degenerative Diseases, National Institute of Respiratory Diseases 'Ismael Cosio Villegas', CP 14080 Mexico City, Mexico
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Ramachandra R, Elmslie KS. EXPRESS: Voltage-dependent sodium (NaV) channels in group IV sensory afferents. Mol Pain 2016; 12:12/0/1744806916660721. [PMID: 27385723 PMCID: PMC4956173 DOI: 10.1177/1744806916660721] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Patients with intermittent claudication suffer from both muscle pain and an exacerbated exercise pressor reflex. Excitability of the group III and group IV afferent fibers mediating these functions is controlled in part by voltage-dependent sodium (NaV) channels. We previously found tetrodotoxin-resistant NaV1.8 channels to be the primary type in muscle afferent somata. However, action potentials in group III and IV afferent axons are blocked by TTX, supporting a minimal role of NaV1.8 channels. To address these apparent differences in NaV channel expression between axon and soma, we used immunohistochemistry to identify the NaV channels expressed in group IV axons within the gastrocnemius muscle and the dorsal root ganglia sections. Positive labeling by an antibody against the neurofilament protein peripherin was used to identify group IV neurons and axons. We show that >67% of group IV fibers express NaV1.8, NaV1.6, or NaV1.7. Interestingly, expression of NaV1.8 channels in group IV somata was significantly higher than in the fibers, whereas there were no significant differences for either NaV1.6 or NaV1.7. When combined with previous work, our results suggest that NaV1.8 channels are expressed in most group IV axons, but that, under normal conditions, NaV1.6 and/or NaV1.7 play a more important role in action potential generation to signal muscle pain and the exercise pressor reflex.
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Affiliation(s)
- Renuka Ramachandra
- The Baker Laboratory of Pharmacology, Department of Pharmacology, AT Still University of Health Sciences, Kirksville, MO, USA
- Renuka Ramachandra, The Baker Laboratory of Pharmacology, Department of Pharmacology, Kirksville College of Osteopathic Medicine, AT Still University of Health Sciences, Kirksville, MO 63501, USA.
| | - Keith S Elmslie
- The Baker Laboratory of Pharmacology, Department of Pharmacology, AT Still University of Health Sciences, Kirksville, MO, USA
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15
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Telinius N, Majgaard J, Kim S, Katballe N, Pahle E, Nielsen J, Hjortdal V, Aalkjaer C, Boedtkjer DB. Voltage-gated sodium channels contribute to action potentials and spontaneous contractility in isolated human lymphatic vessels. J Physiol 2015; 593:3109-22. [PMID: 25969124 PMCID: PMC4532530 DOI: 10.1113/jp270166] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 05/05/2015] [Indexed: 12/31/2022] Open
Abstract
Voltage-gated sodium channels (VGSC) play a key role for initiating action potentials (AP) in excitable cells. VGSC in human lymphatic vessels have not been investigated. In the present study, we report the electrical activity and APs of small human lymphatic collecting vessels, as well as mRNA expression and function of VGSC in small and large human lymphatic vessels. The VGSC blocker TTX inhibited spontaneous contractions in six of 10 spontaneously active vessels, whereas ranolazine, which has a narrower VGSC blocking profile, had no influence on spontaneous activity. TTX did not affect noradrenaline-induced contractions. The VGSC opener veratridine induced contractions in a concentration-dependent manner (0.1-30 μm) eliciting a stable tonic contraction and membrane depolarization to -18 ± 0.6 mV. Veratridine-induced depolarizations and contractions were reversed ∼80% by TTX, and were dependent on Ca(2+) influx via L-type calcium channels and the sodium-calcium exchanger in reverse mode. Molecular analysis determined NaV 1.3 to be the predominantly expressed VGSC isoform. Electrophysiology of mesenteric lymphatics determined the resting membrane potential to be -45 ± 1.7 mV. Spontaneous APs were preceded by a slow depolarization of 5.3 ± 0.6 mV after which a spike was elicited that almost completely repolarized before immediately depolarizing again to plateau. Vessels transiently hyperpolarized prior to returning to the resting membrane potential. TTX application blocked APs. We have shown that VGSC are necessary for initiating and maintaining APs and spontaneous contractions in human lymphatic vessels and our data suggest the main contribution from comes NaV 1.3. We have also shown that activation of these channels augments the contractile activity of the vessels.
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Affiliation(s)
- Niklas Telinius
- Department of Biomedicine, Aarhus UniversityAarhus, Denmark
- Department of Cardiothoracic Surgery, Aarhus University HospitalAarhus, Denmark
| | - Jens Majgaard
- Department of Biomedicine, Aarhus UniversityAarhus, Denmark
| | - Sukhan Kim
- Department of Biomedicine, Aarhus UniversityAarhus, Denmark
| | - Niels Katballe
- Department of Biomedicine, Aarhus UniversityAarhus, Denmark
| | - Einar Pahle
- Department of Surgery, Viborg HospitalViborg, Denmark
| | - Jørn Nielsen
- Department of Surgery, Viborg HospitalViborg, Denmark
| | - Vibeke Hjortdal
- Department of Cardiothoracic Surgery, Aarhus University HospitalAarhus, Denmark
| | | | - Donna Briggs Boedtkjer
- Department of Biomedicine, Aarhus UniversityAarhus, Denmark
- Department of Cardiothoracic Surgery, Aarhus University HospitalAarhus, Denmark
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16
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Rice FL, Albrecht PJ, Wymer JP, Black JA, Merkies IS, Faber CG, Waxman SG. Sodium channel Nav1.7 in vascular myocytes, endothelium, and innervating axons in human skin. Mol Pain 2015; 11:26. [PMID: 25957174 PMCID: PMC4447014 DOI: 10.1186/s12990-015-0024-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 04/24/2015] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The skin is a morphologically complex organ that serves multiple complementary functions, including an important role in thermoregulation, which is mediated by a rich vasculature that is innervated by sympathetic and sensory endings. Two autosomal dominant disorders characterized by episodes of severe pain, inherited erythromelalgia (IEM) and paroxysmal extreme pain disorder (PEPD) have been directly linked to mutations that enhance the function of sodium channel Nav1.7. Pain attacks are accompanied by reddening of the skin in both disorders. Nav1.7 is known to be expressed at relatively high levels within both dorsal root ganglion (DRG) and sympathetic ganglion neurons, and mutations that enhance the activity of Nav1.7 have been shown to have profound effects on the excitability of both cell-types, suggesting that dysfunction of sympathetic and/or sensory fibers, which release vasoactive peptides at skin vasculature, may contribute to skin reddening in IEM and PEPD. RESULTS In the present study, we demonstrate that smooth muscle cells of cutaneous arterioles and arteriole-venule shunts (AVS) in the skin express sodium channel Nav1.7. Moreover, Nav1.7 is expressed by endothelial cells lining the arterioles and AVS and by sensory and sympathetic fibers innervating these vascular elements. CONCLUSIONS These observations suggest that the activity of mutant Nav1.7 channels in smooth muscle cells of skin vasculature and innervating sensory and sympathetic fibers contribute to the skin reddening and/or pain in IEM and PEPD.
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Affiliation(s)
- Frank L Rice
- Integrated Tissue Dynamics, LLC, Rensselaer, NY, 12144, USA.
| | - Phillip J Albrecht
- Integrated Tissue Dynamics, LLC, Rensselaer, NY, 12144, USA. .,Department of Neurology, Albany Medical College, Albany, NY, 12209, USA.
| | - James P Wymer
- Department of Neurology, Albany Medical College, Albany, NY, 12209, USA.
| | - Joel A Black
- Center for Neuroscience & Regeneration Research, Yale University School of Medicine, West Haven, CT, 06516, USA. .,Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, CT, 06516, USA.
| | - Ingemar Sj Merkies
- Department of Neurology, Spaarne Hospital, Hoofddorp, the Netherlands. .,Department of Neurology, Maastricht University Medical Center, Maastricht, the Netherlands.
| | - Catharina G Faber
- Department of Neurology, Maastricht University Medical Center, Maastricht, the Netherlands.
| | - Stephen G Waxman
- Center for Neuroscience & Regeneration Research, Yale University School of Medicine, West Haven, CT, 06516, USA. .,Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, CT, 06516, USA.
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17
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Rocchetti M, Sala L, Rizzetto R, Staszewsky LI, Alemanni M, Zambelli V, Russo I, Barile L, Cornaghi L, Altomare C, Ronchi C, Mostacciuolo G, Lucchetti J, Gobbi M, Latini R, Zaza A. Ranolazine prevents INaL enhancement and blunts myocardial remodelling in a model of pulmonary hypertension. Cardiovasc Res 2014; 104:37-48. [DOI: 10.1093/cvr/cvu188] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Makino A, Firth AL, Yuan JXJ. Endothelial and smooth muscle cell ion channels in pulmonary vasoconstriction and vascular remodeling. Compr Physiol 2013; 1:1555-602. [PMID: 23733654 DOI: 10.1002/cphy.c100023] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The pulmonary circulation is a low resistance and low pressure system. Sustained pulmonary vasoconstriction and excessive vascular remodeling often occur under pathophysiological conditions such as in patients with pulmonary hypertension. Pulmonary vasoconstriction is a consequence of smooth muscle contraction. Many factors released from the endothelium contribute to regulating pulmonary vascular tone, while the extracellular matrix in the adventitia is the major determinant of vascular wall compliance. Pulmonary vascular remodeling is characterized by adventitial and medial hypertrophy due to fibroblast and smooth muscle cell proliferation, neointimal proliferation, intimal, and plexiform lesions that obliterate the lumen, muscularization of precapillary arterioles, and in situ thrombosis. A rise in cytosolic free Ca(2+) concentration ([Ca(2+)]cyt) in pulmonary artery smooth muscle cells (PASMC) is a major trigger for pulmonary vasoconstriction, while increased release of mitogenic factors, upregulation (or downregulation) of ion channels and transporters, and abnormalities in intracellular signaling cascades are key to the remodeling of the pulmonary vasculature. Changes in the expression, function, and regulation of ion channels in PASMC and pulmonary arterial endothelial cells play an important role in the regulation of vascular tone and development of vascular remodeling. This article will focus on describing the ion channels and transporters that are involved in the regulation of pulmonary vascular function and structure and illustrating the potential pathogenic role of ion channels and transporters in the development of pulmonary vascular disease.
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Affiliation(s)
- Ayako Makino
- Department of Medicine, The University of Illinois at Chicago, Chicago, Illinois, USA
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19
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Zheng S, Black DL. Alternative pre-mRNA splicing in neurons: growing up and extending its reach. Trends Genet 2013; 29:442-8. [PMID: 23648015 PMCID: PMC3959871 DOI: 10.1016/j.tig.2013.04.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 03/20/2013] [Accepted: 04/04/2013] [Indexed: 11/18/2022]
Abstract
Alternative pre-mRNA splicing determines the protein output of most neuronally expressed genes. Many examples have been described of protein function being modulated by coding changes in different mRNA isoforms. Several recent studies demonstrate that, through the coupling of splicing to other processes of mRNA metabolism, alternative splicing can also act as an on/off switch for gene expression. Other regulated splicing events may determine how an mRNA is utilized in its later cytoplasmic life by changing its localization or translation. These studies make clear that the multiple steps of post-transcriptional gene regulation are strongly linked. Together, these regulatory process play key roles in all aspects of the cell biology of neurons, from their initial differentiation, to their choice of connections, and finally to their function with mature circuits.
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Affiliation(s)
- Sika Zheng
- Department of Microbiology, Immunology, and Molecular Genetics, Howard Hughes Medical Institute, UCLA, David Geffen School of Medicine, UCLA, 6780 MRL Bldg, 675 Charles Young Dr. S. Los Angeles, CA 90095-1662, (310) 794-7644
| | - Douglas L. Black
- Department of Microbiology, Immunology, and Molecular Genetics, Howard Hughes Medical Institute, UCLA, David Geffen School of Medicine, UCLA, 6780 MRL Bldg, 675 Charles Young Dr. S. Los Angeles, CA 90095-1662, (310) 794-7644
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20
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Bradley E, Webb TI, Hollywood MA, Sergeant GP, McHale NG, Thornbury KD. The cardiac sodium current Na(v)1.5 is functionally expressed in rabbit bronchial smooth muscle cells. Am J Physiol Cell Physiol 2013; 305:C427-35. [PMID: 23784541 DOI: 10.1152/ajpcell.00034.2013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A collagenase-proteinase mixture was used to isolate airway smooth muscle cells (ASMC) from rabbit bronchi, and membrane currents were recorded using the whole cell patch-clamp technique. Stepping from -100 mV to a test potential of -40 mV evoked a fast voltage-dependent Na(+) current, sometimes with an amplitude of several nanoamperes. The current disappeared within 15 min of exposure to papain + DTT (n = 6). Comparison of the current in ASMC with current mediated by NaV1.5 α-subunits expressed in human embryonic kidney cells revealed similar voltage dependences of activation (V1/2 = -42 mV for NaV1.5) and sensitivities to TTX (IC50 = 1.1 and 1.2 μM for ASMC and NaV1.5, respectively). The current in ASMC was also blocked by lidocaine (IC50 = 160 μM). Although veratridine, an agonist of voltage-gated Na(+) channels, reduced the peak current by 33%, it slowed inactivation, resulting in a fourfold increase in sustained current (measured at 25 ms after onset). In current-clamp mode, veratridine prolonged evoked action potentials from 37 ± 9 to 1,053 ± 410 ms (n = 8). Primers for NaV1.2-1.9 were used to amplify mRNA from groups of ∼20 isolated ASMC and from whole bronchial tissue by RT-PCR. Transcripts for NaV1.2, NaV1.3, and NaV1.5-1.9 were detected in whole tissue, but only NaV1.2 and NaV1.5 were detected in single cells. We conclude that freshly dispersed rabbit ASMC express a fast voltage-gated Na(+) current that is mediated mainly by the NaV1.5 subtype.
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Affiliation(s)
- E Bradley
- Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
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21
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Dib-Hajj SD, Yang Y, Black JA, Waxman SG. The NaV1.7 sodium channel: from molecule to man. Nat Rev Neurosci 2012; 14:49-62. [DOI: 10.1038/nrn3404] [Citation(s) in RCA: 377] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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22
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Kis-Toth K, Hajdu P, Bacskai I, Szilagyi O, Papp F, Szanto A, Posta E, Gogolak P, Panyi G, Rajnavolgyi E. Voltage-Gated Sodium Channel Nav1.7 Maintains the Membrane Potential and Regulates the Activation and Chemokine-Induced Migration of a Monocyte-Derived Dendritic Cell Subset. THE JOURNAL OF IMMUNOLOGY 2011; 187:1273-80. [DOI: 10.4049/jimmunol.1003345] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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23
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Bocquet A, Sablayrolles S, Vacher B, Le Grand B. F 15845, a new blocker of the persistent sodium current prevents consequences of hypoxia in rat femoral artery. Br J Pharmacol 2010; 161:405-15. [PMID: 20735424 PMCID: PMC2989591 DOI: 10.1111/j.1476-5381.2010.00912.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 03/18/2010] [Accepted: 04/14/2010] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The persistent sodium current is involved in myocardial ischaemia and is selectively inhibited by the newly described 3-(R)-[3-(2-methoxyphenylthio-2-(S)-methylpropyl]amino-3,4-dihydro-2H-1,5-benzoxathiepine bromhydrate (F 15845). Here, we describe the pharmacological profile of F 15845 against the effects of hypoxia in femoral arteries in vitro. EXPERIMENTAL APPROACH Isometric tension measurement of rat isolated femoral arteries was used to characterize the protective effect of F 15845 against contraction of the vessels induced by veratrine (100 microg.mL(-1)) or hypoxia. KEY RESULTS Rat femoral artery expressed the Na(v)1.5 channel isoform. When exposed to veratrine (100 microg.mL(-1)), vessels developed a rapid and strong contraction that was abolished by both absence of sodium and blockade of the Na(+)/Ca(++) exchanger by KB-R7943 (10 and 32 micromol.L(-1)) or treatment with F 15845. When used before veratrine exposure, the potency of F 15845 depended on the extracellular K(+) concentration (IC(50)= 11 and 0.77 micromol.L(-1) for 5 and 20 mmol.L(-1) KCl, respectively), whereas its potency was unaffected by extracellular K(+) concentration when given after veratrine. F 15845 did not affect either KCl (80 mmol.L(-1)) or phenylephrine-induced femoral artery contraction. Moreover, endothelium disruption did not affect the protective effect of F 15845 against veratrine-induced femoral artery contraction, suggesting a mechanism of action dependent on smooth muscle cells. Finally, F 15845 prevented in a concentration-dependent manner rat femoral artery contraction induced by hypoxia. CONCLUSION AND IMPLICATIONS F 15845, a selective blocker of the persistent sodium current prevented vascular contraction induced by hypoxic conditions.
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Affiliation(s)
- A Bocquet
- Centre de Recherche Pierre Fabre, Castres cedex, France
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24
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Oguri A, Tanaka T, Iida H, Meguro K, Takano H, Oonuma H, Nishimura S, Morita T, Yamasoba T, Nagai R, Nakajima T. Involvement of CaV3.1 T-type calcium channels in cell proliferation in mouse preadipocytes. Am J Physiol Cell Physiol 2010; 298:C1414-23. [PMID: 20457833 DOI: 10.1152/ajpcell.00488.2009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Voltage-gated Ca(2+) channels (Ca(V)) are ubiquitously expressed in various cell types and play vital roles in regulation of cellular functions including proliferation. However, the molecular identities and function of Ca(V) remained unexplored in preadipocytes. Therefore, whole cell voltage-clamp technique, conventional/quantitative real-time RT-PCR, Western blot, small interfering RNA (siRNA) experiments, and immunohistochemical analysis were applied in mouse primary cultured preadipocytes as well as mouse 3T3-L1 preadipocytes. The effects of Ca(V) blockers on cell proliferation and cell cycle were also investigated. Whole cell recordings of 3T3-L1 preadipocytes showed low-threshold Ca(V), which could be inhibited by mibefradil, Ni(2+) (IC(50) of 200 muM), and NNC55-0396. Dominant expression of alpha(1G) mRNA was detected among Ca(V) transcripts (alpha(1A)-alpha(1I)), supported by expression of Ca(V)3.1 protein encoded by alpha(1G) gene, with immunohistochemical studies and Western blot analysis. siRNA targeted for alpha(1G) markedly inhibited Ca(V). Dominant expression of alpha(1G) mRNA and expression of Ca(V)3.1 protein were also observed in mouse primary cultured preadipocytes. Expression level of alpha(1G) mRNA and Ca(V)3.1 protein significantly decreased in differentiated adipocytes. Mibefradil, NNC55-0396, a selective T-type Ca(V) blocker, but not diltiazem, inhibited cell proliferation in response to serum. NNC55-0396 and siRNA targeted for alpha(1G) also prevented cell cycle entry/progression. The present study demonstrates that the Ca(V)3.1 T-type Ca(2+) channel encoded by alpha(1G) subtype is the dominant Ca(V) in mouse preadipocytes and may play a role in regulating preadipocyte proliferation, a key step in adipose tissue development.
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Affiliation(s)
- Atsushi Oguri
- Department of Cardiovascular Medicine, University of Tokyo, Tokyo, Japan
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25
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Fort A, Cordaillat M, Thollon C, Salazar G, Mechaly I, Villeneuve N, Vilaine JP, Richard S, Virsolvy A. New insights in the contribution of voltage-gated Na(v) channels to rat aorta contraction. PLoS One 2009; 4:e7360. [PMID: 19809503 PMCID: PMC2752992 DOI: 10.1371/journal.pone.0007360] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2009] [Accepted: 09/14/2009] [Indexed: 01/17/2023] Open
Abstract
Background Despite increasing evidence for the presence of voltage-gated Na+ channels (Nav) isoforms and measurements of Nav channel currents with the patch-clamp technique in arterial myocytes, no information is available to date as to whether or not Nav channels play a functional role in arteries. The aim of the present work was to look for a physiological role of Nav channels in the control of rat aortic contraction. Methodology/Principal Findings Nav channels were detected in the aortic media by Western blot analysis and double immunofluorescence labeling for Nav channels and smooth muscle α-actin using specific antibodies. In parallel, using real time RT-PCR, we identified three Nav transcripts: Nav1.2, Nav1.3, and Nav1.5. Only the Nav1.2 isoform was found in the intact media and in freshly isolated myocytes excluding contamination by other cell types. Using the specific Nav channel agonist veratridine and antagonist tetrodotoxin (TTX), we unmasked a contribution of these channels in the response to the depolarizing agent KCl on rat aortic isometric tension recorded from endothelium-denuded aortic rings. Experimental conditions excluded a contribution of Nav channels from the perivascular sympathetic nerve terminals. Addition of low concentrations of KCl (2–10 mM), which induced moderate membrane depolarization (e.g., from −55.9±1.4 mV to −45.9±1.2 mV at 10 mmol/L as measured with microelectrodes), triggered a contraction potentiated by veratridine (100 µM) and blocked by TTX (1 µM). KB-R7943, an inhibitor of the reverse mode of the Na+/Ca2+ exchanger, mimicked the effect of TTX and had no additive effect in presence of TTX. Conclusions/Significance These results define a new role for Nav channels in arterial physiology, and suggest that the TTX-sensitive Nav1.2 isoform, together with the Na+/Ca2+ exchanger, contributes to the contractile response of aortic myocytes at physiological range of membrane depolarization.
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Affiliation(s)
- Aurélie Fort
- Inserm U637, Université Montpellier1 & 2, Montpellier, France
| | | | - Catherine Thollon
- Cardiovascular Division, Institut de Recherches Servier, Suresnes, France
| | | | - Ilana Mechaly
- Inserm U583, Université Montpellier2, Montpellier, France
| | - Nicole Villeneuve
- Cardiovascular Division, Institut de Recherches Servier, Suresnes, France
| | - Jean-Paul Vilaine
- Cardiovascular Division, Institut de Recherches Servier, Suresnes, France
| | - Sylvain Richard
- Inserm U637, Université Montpellier1 & 2, Montpellier, France
- * E-mail:
| | - Anne Virsolvy
- Inserm U637, Université Montpellier1 & 2, Montpellier, France
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Visualizing sodium dynamics in isolated cardiomyocytes using fluorescent nanosensors. Proc Natl Acad Sci U S A 2009; 106:16145-50. [PMID: 19805271 DOI: 10.1073/pnas.0905909106] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Regulation of sodium flux across the cell membrane plays a vital role in the generation of action potentials and regulation of membrane excitability in cells such as cardiomyocytes and neurons. Alteration of sodium channel function has been implicated in diseases such as epilepsy, long QT syndrome, and heart failure. However, single cell imaging of sodium dynamics has been limited due to the narrow selection of fluorescent sodium indicators available to researchers. Here we report, the detection of spatially defined sodium activity during action potentials. Fluorescent nanosensors that measure sodium in real-time, are reversible and are completely selective over other cations such as potassium that were used to image sodium. The use of the nanosensors in vitro was validated by determining drug-induced activation in heterologous cells transfected with the voltage-gated sodium channel Na(V)1.7. Spatial information of sodium concentrations during action potentials will provide insight at the cellular level on the role of sodium and how slight changes in sodium channel function can affect the entirety of an action potential.
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27
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Nakajima T, Kubota N, Tsutsumi T, Oguri A, Imuta H, Jo T, Oonuma H, Soma M, Meguro K, Takano H, Nagase T, Nagata T. Eicosapentaenoic acid inhibits voltage-gated sodium channels and invasiveness in prostate cancer cells. Br J Pharmacol 2009; 156:420-31. [PMID: 19154441 DOI: 10.1111/j.1476-5381.2008.00059.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The voltage-gated Na(+) channels (Na(v)) and their corresponding current (I(Na)) are involved in several cellular processes, crucial to metastasis of cancer cells. We investigated the effects of eicosapentaenoic (EPA), an omega-3 polyunsaturated fatty acid, on I(Na) and metastatic functions (cell proliferation, endocytosis and invasion) in human and rat prostate cancer cell lines (PC-3 and Mat-LyLu cells). EXPERIMENTAL APPROACH The whole-cell voltage clamp technique and conventional/quantitative real-time reverse transcriptase polymerase chain reaction analysis were used. The presence of Na(v) proteins was shown by immunohistochemical methods. Alterations in the fatty acid composition of phospholipids after treatment with EPA and metastatic functions were also examined. KEY RESULTS A transient inward Na(+) current (I(Na)), highly sensitive to tetrodotoxin, and Na(V) proteins were found in these cells. Expression of Na(V)1.6 and Na(V)1.7 transcripts (SCN8A and SCN9A) was predominant in PC-3 cells, while Na(V)1.7 transcript (SCN9A) was the major component in Mat-LyLu cells. Tetrodotoxin or synthetic small interfering RNA targeted for SCN8A and SCN9A inhibited metastatic functions (endocytosis and invasion), but failed to inhibit proliferation in PC-3 cells. Exposure to EPA produced a rapid and concentration-dependent suppression of I(Na). In cells chronically treated (up to 72h) with EPA, the EPA content of cell lipids increased time-dependently, while arachidonic acid content decreased. Treatment of PC-3 cells with EPA decreased levels of mRNA for SCN9A and SCN8A, cell proliferation, invasion and endocytosis. CONCLUSION AND IMPLICATIONS Treatment with EPA inhibited I(Na) directly and also indirectly, by down-regulation of Na(v) mRNA expression in prostate cancer cells, thus inhibiting their metastatic potential.
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Affiliation(s)
- T Nakajima
- Department of Ischemic Circulatory Physiology, The University of Tokyo, Japan.
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Meguro K, Iida H, Takano H, Morita T, Sata M, Nagai R, Nakajima T. Function and role of voltage-gated sodium channel NaV1.7 expressed in aortic smooth muscle cells. Am J Physiol Heart Circ Physiol 2008; 296:H211-9. [PMID: 18978189 DOI: 10.1152/ajpheart.00960.2008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Voltage-gated Na(+) channel currents (I(Na)) are expressed in several types of smooth muscle cells. The purpose of this study was to evaluate the expression of I(Na), its functional role, pathophysiology in cultured human (hASMCs) and rabbit aortic smooth muscle cells (rASMCs), and its association with vascular intimal hyperplasia. In whole cell voltage clamp, I(Na) was observed at potential positive to -40 mV, was blocked by tetrodotoxin (TTX), and replacing extracellular Na(+) with N-methyl-d-glucamine in cultured hASMCs. In contrast to native aorta, cultured hASMCs strongly expressed SCN9A encoding Na(V)1.7, as determined by quantitative RT-PCR. I(Na) was abolished by the treatment with SCN9A small-interfering (si)RNA (P < 0.01). TTX and SCN9A siRNA significantly inhibited cell migration (P < 0.01, respectively) and horseradish peroxidase uptake (P < 0.01, respectively). TTX also significantly reduced the secretion of matrix metalloproteinase-2 6 and 12 h after the treatment (P < 0.01 and P < 0.05, respectively). However, neither TTX nor siRNA had any effect on cell proliferation. L-type Ca(2+) channel current was recorded, and I(Na) was not observed in freshly isolated rASMCs, whereas TTX-sensitive I(Na) was recorded in cultured rASMCs. Quantitative RT-PCR and immunostaining for Na(V)1.7 revealed the prominent expression of SCN9A in cultured rASMCs and aorta 48 h after balloon injury but not in native aorta. In conclusion, these studies show that I(Na) is expressed in cultured and diseased conditions but not in normal aorta. The Na(V)1.7 plays an important role in cell migration, endocytosis, and secretion. Na(V)1.7 is also expressed in aorta after balloon injury, suggesting a potential role for Na(V)1.7 in the progression of intimal hyperplasia.
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Affiliation(s)
- Kentaro Meguro
- Dept. of Cardiovascular Medicine, Univ. of Tokyo Graduate School of Medicine, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8655, Japan.
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Nakajima T, Jo T, Meguro K, Oonuma H, Ma J, Kubota N, Imuta H, Takano H, Iida H, Nagase T, Nagata T. Effect of dexamethasone on voltage-gated Na+ channel in cultured human bronchial smooth muscle cells. Life Sci 2008; 82:1210-5. [PMID: 18485418 DOI: 10.1016/j.lfs.2008.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2007] [Revised: 04/04/2008] [Accepted: 04/11/2008] [Indexed: 11/15/2022]
Abstract
Voltage-gated Na(+) channel (I(Na)) encoded by SCN9A mRNA is expressed in cultured human bronchial smooth muscle cells. We investigated the effects of dexamethasone on I(Na), by using whole-cell voltage clamp techniques, reverse transcriptase/polymerase chain reaction (RT-PCR), and quantitative real-time RT-PCR. Acute application of dexamethasone (10(-6) M) did not affect I(Na). However, the percentage of the cells with I(Na) was significantly less in cells pretreated with dexamethasone for 48 h, and the current-density of I(Na) adjusted by cell capacitance in cells with I(Na) was also decreased in cells treated with dexamethasone. RT-PCR analysis showed that alpha and beta subunits mRNA of I(Na) mainly consisted of SCN9A and SCN1beta, respectively. Treatment with dexamethasone for 24-48 h inhibited the expression of SCN9A mRNA. The inhibitory effect of dexamethasone was concentration-dependent, and was observed at a concentration higher than 0.1 nM. The effect of dexamethasone on SCN9A mRNA was not blocked by spironolactone, but inhibited by mifepristone. The inhibitory effects of dexamethasone on SCN9A mRNA could not be explained by the changes of the stabilization of mRNA measured by using actinomycin D. These results suggest that dexamethasone inhibited I(Na) encoded by SCN9A mRNA in cultured human bronchial smooth muscle cells by inhibiting the transcription via the glucocorticoid receptor.
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Affiliation(s)
- Toshiaki Nakajima
- Department of Ischemia Circulatory Physiology, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan.
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30
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Molecular and biophysical properties of voltage-gated Na+ channels in murine vas deferens. Biophys J 2008; 94:3340-51. [PMID: 18192366 PMCID: PMC2275690 DOI: 10.1529/biophysj.107.117192] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
The biological and molecular properties of tetrodotoxin (TTX)-sensitive voltage-gated Na(+) currents (I(Na)) in murine vas deferens myocytes were investigated using patch-clamp techniques and molecular biological analyses. In whole-cell configuration, a fast, transient inward current was evoked in the presence of Cd(2+), and was abolished by TTX (K(d) = 11.2 nM), mibefradil (K(d) = 3.3 microM), and external replacement of Na(+) with monovalent cations (TEA(+), Tris(+), and NMDG(+)). The fast transient inward current was enhanced by veratridine, an activator of voltage-gated Na(+) channels, suggesting that the fast transient inward current was a TTX-sensitive I(Na). The values for half-maximal (V(half)) inactivation and activation of I(Na) were -46.3 mV and -26.0 mV, respectively. RT-PCR analysis revealed the expression of Scn1a, 2a, and 8a transcripts. The Scn8a transcript and the alpha-subunit protein of Na(V)1.6 were detected in smooth muscle layers. Using Na(V)1.6-null mice (Na(V)1.6(-/-)) lacking the expression of the Na(+) channel gene, Scn8a, I(Na) were not detected in dispersed smooth muscle cells from the vas deferens, while TTX-sensitive I(Na) were recorded in their wild-type (Na(V)1.6(+/+)) littermates. This study demonstrates that the molecular identity of the voltage-gated Na(+) channels responsible for the TTX-sensitive I(Na) in murine vas deferens myocytes is primarily Na(V)1.6.
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31
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Dib-Hajj SD, Cummins TR, Black JA, Waxman SG. From genes to pain: Nav1.7 and human pain disorders. Trends Neurosci 2007; 30:555-63. [DOI: 10.1016/j.tins.2007.08.004] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2007] [Revised: 06/22/2007] [Accepted: 08/08/2007] [Indexed: 12/19/2022]
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Diss JKJ, Fraser SP, Walker MM, Patel A, Latchman DS, Djamgoz MBA. β-Subunits of voltage-gated sodium channels in human prostate cancer: quantitative in vitro and in vivo analyses of mRNA expression. Prostate Cancer Prostatic Dis 2007; 11:325-33. [PMID: 17893701 DOI: 10.1038/sj.pcan.4501012] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We previously identified high levels of Na(v)1.7 voltage-gated sodium channel alpha-subunit (VGSCalpha) mRNA and protein in human prostate cancer cells and tissues. Here, we investigated auxillary beta-subunit (VGSCbetas) expression. In vitro, the combined expression of all four VGSCbetas was significantly (approximately 4.5-fold) higher in strongly compared to weakly metastatic cells. This was mainly due to increased beta1-expression, which was under androgenic control. In vivo, beta1-beta4 mRNAs were detectable and their expression in CaP vs non-CaP tissues generally reflected the in vitro levels in relation to metastatic potential. The possible role(s) of VGSCbetas (VGSCalpha-associated and VGSCalpha-independent) in prostate cancer are discussed.
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Affiliation(s)
- J K J Diss
- Medical Molecular Biology Unit, Institute of Child Health, University College London, London, UK.
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Sage D, Salin P, Alcaraz G, Castets F, Giraud P, Crest M, Mazet B, Clerc N. Nav1.7 and Nav1.3 are the only tetrodotoxin-sensitive sodium channels expressed by the adult guinea pig enteric nervous system. J Comp Neurol 2007; 504:363-78. [PMID: 17663442 DOI: 10.1002/cne.21450] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The types of sodium channels that are expressed by neurons shape the rising phase of action potentials and influence patterns of action potential discharge. With regard to the enteric nervous system (ENS), there is uncertainty about which channels are expressed, and in particular it is unknown whether Na(v)1.7 is present. We designed specific probes for the guinea pig Na(v)1.7 alpha subunit as well as for the other tetrodotoxin (TTX)-sensitive alpha subunits (Na(v)1.1, Na(v)1.2, Na(v)1.3, and Na(v)1.6) in order to perform in situ hybridization (ISH) histochemistry on guinea pig myenteric ganglia. We established that only Na(v)1.7 mRNA and Na(v)1.3 mRNA are expressed in these ganglia. The ISH signal for Na(v)1.7 transcripts was found in seemingly all the myenteric neurons. The expression of the Na(v)1.3 alpha subunit was confirmed by immunohistochemistry in a large proportion (62%) of the myenteric neuron population. This population included enteric sensory neurons. Na(v)1.6 immunoreactivity, absent from myenteric neurons, was detected in glial cells only when a high anti-Na(v)1.6 antibody concentration was used. This suggests that the Na(v)1.6 alpha subunit and mRNA are present only at low levels, which is consistent with the fact that no Na(v)1.6 mRNA could be detected in the ENS by ISH. The fact that adult myenteric neurons are endowed with only two TTX-sensitive alpha subunits, namely, Na(v)1.3 and Na(v)1.7, emphasizes the singularity of the ENS. Both these subunits, known to have slow-inactivation kinetics, are well adapted for generating action potentials from slow excitatory postsynaptic potentials, a mode of synaptic transmission that applies to all ENS neuron types.
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Affiliation(s)
- D Sage
- Laboratoire Neurophysiologie Cellulaire, UMR 6150 Centre National de la Recherche Scientifique (CNRS)/Université de la Méditerranée, Institut Fédératif de Recherche Jean Roche, Faculté de Médecine, 13916 Marseille, France
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Lee-Kwon W, Goo JH, Zhang Z, Silldorff EP, Pallone TL. Vasa recta voltage-gated Na+ channel Nav1.3 is regulated by calmodulin. Am J Physiol Renal Physiol 2006; 292:F404-14. [PMID: 16912065 DOI: 10.1152/ajprenal.00070.2006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Rat descending vasa recta (DVR) express a tetrodotoxin (TTX)-sensitive voltage-operated Na(+) (Na(V)) conductance. We examined expression of Na(V) isoforms in DVR and tested for regulation of Na(V) currents by calmodulin (CaM). RT-PCR in isolated permeabilized DVR using degenerate primers targeted to TTX-sensitive isoforms amplified a product whose sequence identified only Na(V)1.3. Immunoblot of outer medullary homogenate verified Na(V)1.3 expression, and fluorescent immunochemistry showed Na(V)1.3 expression in isolated vessels. Immunochemistry in outer medullary serial sections confirmed that Na(V)1.3 is confined to alpha-smooth muscle actin-positive vascular bundles. Na(V)1.3 possesses a COOH-terminal CaM binding motifs. Using pull-down assays and immunoprecipitation experiments, we verified that CaM binds to either full-length Na(V)1.3 or a GST-Na(V)1.3 COOH-terminal fusion protein. In patch-clamp experiments, Na(V) currents were suppressed by calmodulin inhibitory peptide (CIP; 100 nM) or the CaM inhibitor N-(6-aminohexyl)-5-chloro-1-naphthalene-sulphonamide hydrochloride (W7). Neither CIP nor W7 altered the voltage dependence of pericyte Na(V) currents; however, raising electrode free Ca(2+) from 20 to approximately 2,000 nM produced a depolarizing shift of activation. In vitro binding of CaM to GST-Na(V)1.3C was not affected by Ca(2+) concentration. We conclude that Na(V)1.3 is expressed by DVR, binds to CaM, and is regulated by CaM and Ca(2+). Inhibition of CaM binding suppresses pericyte Na(V) currents.
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Affiliation(s)
- Whaseon Lee-Kwon
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore 21201, USA
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35
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Guibert C, Savineau JP, Crevel H, Marthan R, Rousseau E. Effect of short-term organoid culture on the pharmaco-mechanical properties of rat extra- and intrapulmonary arteries. Br J Pharmacol 2006; 146:692-701. [PMID: 16151441 PMCID: PMC1751198 DOI: 10.1038/sj.bjp.0706379] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1 Organoid cultured explants from differentiated tissues have gained renewed interest in the undertaking of physiological and pharmacological studies. In the work herein, we examined the pharmaco-mechanical properties of an in vitro model consisting of organoid cultured rings derived from rat extra- and intrapulmonary arteries, over a period of 4 days in culture. 2 Mechanical changes were quantified using isometric tension measurements on both fresh and cultured pulmonary arterial tissues, with experiments performed in the presence or absence of 10% foetal calf serum. Conventional histochemical and immunofluorescent stainings were also performed to assess tissue structure integrity and apoptosis. 3 The explants developed spontaneous rhythmic contractions (SRC) in approximately half of the vessels. SRC amplitude and time course were modified by conditions and agents acting on membrane potential (high-potassium solutions--levcromakalim, a potassium channel opener), while nitrendipine, an L-type calcium channel blocker, suppressed SRC. 4 Cultured explants also developed a hyper-reactivity to high potassium challenges (10-40 mM). Whereas contraction to serotonin (5-HT) was enhanced in intrapulmonary arteries, contraction to endothelin-1 remained unchanged after 4 days of culture. Serum did not alter contractile properties during the culture period. 5 Endothelial-dependent relaxation was maintained in response to A23187 500 microM, but was abolished in response to 10 microM carbamylcholine. 6 Histological and immuno-histological analyses revealed the absence of hypertrophied vascular wall or apoptosis. 7 In conclusion, the contractile phenotype as well as tissue structure integrity of organoid explants remain essentially intact during short-term culture, making this model suitable for pharmaco-genomic studies.
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Affiliation(s)
- Christelle Guibert
- Laboratoire de Physiologie Cellulaire Respiratoire, INSERM E356, Université Bordeaux 2, France.
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Fulgenzi G, Graciotti L, Faronato M, Soldovieri MV, Miceli F, Amoroso S, Annunziato L, Procopio A, Taglialatela M. Human neoplastic mesothelial cells express voltage-gated sodium channels involved in cell motility. Int J Biochem Cell Biol 2006; 38:1146-59. [PMID: 16458569 DOI: 10.1016/j.biocel.2005.12.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Revised: 11/26/2005] [Accepted: 12/08/2005] [Indexed: 02/07/2023]
Abstract
Given the pivotal role of ion channels in neoplastic transformation, the aim of the present study has been to assess possible differences in the expression patterns of voltage-gated monovalent cationic (Na(+) and K(+)) currents between normal and neoplastic mesothelial cells (NM, MPM, respectively), and to evaluate the role of specific ion channels in mesothelioma cells proliferation, apoptosis, and motility. To achieve this aim, membrane currents expressed in NM and MPM cells derived from surgically-removed human specimens were investigated by means of patch-clamp electrophysiology. NM cells were found to express three main classes of K(+) currents, which were defined as K(IR), maxiK(Ca), and K(V) currents on the basis of their biophysical and pharmacological properties. Each of these K(+) currents was absent in MPM cells; by contrast, MPM cells revealed the novel appearance of tetrodotoxin (TTX)-sensitive voltage-gated Na(+) currents undetected in normal mesothelial cells. Reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time PCR analysis of MPM cells transcripts showed significant expression of the mRNAs encoding for Na(V)1.2, and Na(V)1.6, and Na(V)1.7 (and less so for Na(V)1.3, Na(V)1.4, and Na(V)1.5) main voltage-gated sodium channel (VGSC) alpha-subunit(s). Interestingly, blockade of VGSCs with TTX decreased mesothelioma cell migration in in vitro motility assays; on the other hand, TTX failed to interfere with cell viability, proliferation, and apoptosis progression triggered by UV exposure. In summary, the results of the present study suggest that VGSCs expression in MPM cells may favor the increased motility of the neoplastic cells, a phenotypic feature often associated with the malignant phenotype.
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Affiliation(s)
- Gianluca Fulgenzi
- Department of Molecular Pathology and Innovative Therapies, Polytechnic University of Marche, Via Ranieri, Ancona 60131, Italy
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Kishida S, Nakajima T, Ma J, Jo T, Imuta H, Oonuma H, Iida H, Takano H, Morita T, Nagai R. Amiodarone and N-Desethylamiodarone Enhance Endothelial Nitric Oxide Production in Human Endothelial Cells. Int Heart J 2006; 47:85-93. [PMID: 16479044 DOI: 10.1536/ihj.47.85] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Amiodarone (AM) is a potent vasodilator and exhibits diverse cardiovascular protective effects in vivo, but their underlying mechanisms remain unsettled. We investigated the effects of AM and N-desethylamiodarone (DEA), the major metabolite of AM, on endothelial nitric oxide (NO) production using cultured human umbilical vein endothelial cells (HUVECs). The release of NO was evaluated as measured by nitrite, a stable metabolite of NO, using the Griess reaction and also measured directly by a NO-selective electrode. The expression of each nitric oxide synthase (NOS) mRNA was examined by reverse transcriptase-polymerase chain reaction (RT-PCR), and the effects of AM on eNOS mRNA expression were studied by quantitative real-time RT-PCR. AM and DEA (1-30 microM) enhanced NO production in a concentration-dependent manner. DEA was capable of producing more NO than AM. L-NAME, a nonselective NOS inhibitor, EGTA, a Ca(2+)-chelating agent, and nickel, a nonspecific Ca(2+) blocker, all inhibited AM-induced NO production. However, LY294002, an Akt pathway inhibitor and SB202190, a MAP kinase inhibitor, did not significantly suppress the production. In RT-PCR analysis, only eNOS mRNA was detected. Treatment with AM for 4 hours did not show a significant increase in the expression of eNOS mRNA. AM lower than 30 microM did not induce apoptosis, net cell loss, or LDH release from cells. The present study provides the first evidence that therapeutic concentrations of AM and DEA enhance eNOS-mediated NO production without any toxic or apoptotic effects. This mechanism may underlie the cardiovascular protective effects of AM and its metabolite observed in a clinical setting.
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Affiliation(s)
- Shinya Kishida
- Department of Cardiovascular Medicine, University of Tokyo, Tokyo, Japan
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Saleh S, Yeung SYM, Prestwich S, Pucovsky V, Greenwood I. Electrophysiological and molecular identification of voltage-gated sodium channels in murine vascular myocytes. J Physiol 2005; 568:155-69. [PMID: 16020462 PMCID: PMC1474751 DOI: 10.1113/jphysiol.2005.090951] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Accepted: 07/13/2005] [Indexed: 12/28/2022] Open
Abstract
A voltage-gated Na+ current was characterised in freshly dissociated mouse portal vein (PV) smooth muscle myocytes. The current was found superimposed upon the relatively slow L-type Ca2+ current and was resistant to conventional Ca2+ channel blockers but was abolished by external Na+ replacement and tetrodotoxin (TTX, 1 microM). The molecular identity of the channel responsible for this conductance was determined by RT-PCR where only the transcripts for Na+ channel genes SCN7a, 8a and 9a were detected. The presence of the protein counterparts to the SCN8a and 9a genes (NaV1.6 and NaV1.7, respectively) on the individual smooth muscle myocytes were confirmed in immunocytochemistry, which showed diffuse staining around a predominantly plasmalemmal location. TTX inhibited the action potential in individual myocytes generated in the current clamp mode but isometric tissue tension experiments revealed that TTX (1 and 5 microM) had no effect on the inherent mouse PV rhythmicity. However, the Na+ channel opener veratridine (10 and 50 microM) significantly increased the length of contraction and the interval between contractions. This effect was not influenced by pre-incubation with atropine, prazosin and propranolol, but was reversed by TTX (1 microM) and completely abolished by nicardipine (1 microM). Furthermore, preincubation with the reverse-mode Na+-Ca2+ exchange blocker KB-R7943 (10 microM) also inhibited the veratridine response. We have established for the first time the molecular identity of the voltage-gated Na+ channel in freshly dispersed smooth muscle cells and have shown that these channels can modulate contractility through a novel mechanism of action possibly involving reverse mode Na+-Ca2+ exchange.
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Affiliation(s)
- Sohag Saleh
- Division of Basic Medical Sciences, St George's, University of London, London SW17 0RE, UK
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Berra-Romani R, Blaustein MP, Matteson DR. TTX-sensitive voltage-gated Na+ channels are expressed in mesenteric artery smooth muscle cells. Am J Physiol Heart Circ Physiol 2005; 289:H137-45. [PMID: 15961372 DOI: 10.1152/ajpheart.01156.2004] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The presence and properties of voltage-gated Na+ channels in mesenteric artery smooth muscle cells (SMCs) were studied using whole cell patch-clamp recording. SMCs from mouse and rat mesenteric arteries were enzymatically dissociated using two dissociation protocols with different enzyme combinations. Na+ and Ca2+ channel currents were present in myocytes isolated with collagenase and elastase. In contrast, Na+ currents were not detected, but Ca2+ currents were present in cells isolated with papain and collagenase. Ca2+ currents were blocked by nifedipine. The Na+ current was insensitive to nifedipine, sensitive to changes in the extracellular Na+ concentration, and blocked by tetrodotoxin with an IC50 at 4.3 nM. The Na+ conductance was half maximally activated at -16 mV, and steady-state inactivation was half-maximal at -53 mV. These values are similar to those reported in various SMC types. In the presence of 1 microM batrachotoxin, the Na+ conductance-voltage relationship was shifted by 27 mV in the hyperpolarizing direction, inactivation was almost completely eliminated, and the deactivation rate was decreased. The present study indicates that TTX-sensitive, voltage-gated Na+ channels are present in SMCs from the rat and mouse mesenteric artery. The presence of these channels in freshly isolated SMC depends critically on the enzymatic dissociation conditions. This could resolve controversy about the presence of Na+ channels in arterial smooth muscle.
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Affiliation(s)
- Roberto Berra-Romani
- Dept. of Physiology, Univ. of Maryland School of Medicine, 655 W. Baltimore St., Baltimore, MD 21201, USA
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Jo T, Iida H, Kishida S, Imuta H, Oonuma H, Nagata T, Hara H, Iwasawa K, Soma M, Sato Y, Nagase T, Nagai R, Nakajima T. Acute and chronic effects of eicosapentaenoic acid on voltage-gated sodium channel expressed in cultured human bronchial smooth muscle cells. Biochem Biophys Res Commun 2005; 331:1452-9. [PMID: 15883037 DOI: 10.1016/j.bbrc.2005.04.062] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Indexed: 10/25/2022]
Abstract
This study investigated acute and chronic effects of eicosapentaenoic acid (EPA) on voltage-gated Na+ current (I(Na)) expressed in cultured human bronchial smooth muscle cells (hBSMCs). The whole-cell voltage clamp technique and quantitative real-time RT-PCR analysis were applied. The alterations in the fatty acid composition of phospholipids after treatment with EPA were also examined. Extracellular application of EPA produced a rapid and concentration-dependent suppression of tetrodotoxin-sensitive I(Na) with the half-maximal inhibitory concentration of 2 microM. After washing out EPA with albumin, I(Na) returned to the control level. Similar inhibitory effects were observed regarding other fatty acids (docosahexaenoic, arachidonic, stearic, and oleic acids), but EPA was the most potent inhibitor. The effect of EPA on I(Na) was not blocked by nordihydroguaiaretic acid and indometacin, and was accompanied by a significant shift of the steady-state inactivation curve to more negative potentials. In cells chronically treated with EPA, the EPA content of the cell lipid fraction (mol%) increased time-dependently, while arachidonic acid (AA) decreased, resulting in an increase of EPA to AA ratio. Then, the level of mRNA (SCN9A) encoding I(Na) decreased significantly. These results provide novel evidence that EPA not only rapidly inhibits I(Na), but also reduces the mRNA levels of the Na+ channel after cellular incorporation of EPA in cultured hBSMCs.
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Affiliation(s)
- Taisuke Jo
- Department of Cardiovascular and Respiratory Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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Ma J, Iida H, Jo T, Takano H, Oonuma H, Morita T, Toyo-Oka T, Omata M, Nagai R, Okuda Y, Yamada N, Nakajima T. Ursodeoxycholic acid inhibits endothelin-1 production in human vascular endothelial cells. Eur J Pharmacol 2004; 505:67-74. [PMID: 15556138 DOI: 10.1016/j.ejphar.2004.10.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Revised: 10/13/2004] [Accepted: 10/14/2004] [Indexed: 11/20/2022]
Abstract
Endothelin-1 is known to be implicated in the pathogenesis of hepatobiliary diseases such as cirrhosis, especially in portal hypertension. This study aimed to investigate the effects of ursodeoxycholic acid on endothelin-1 production in human endothelial cells. The effects of ursodeoxycholic acid and its conjugates (tauroursodeoxycholic and glycoursodeoxycholic acids) on endothelin-1 production as well as nitric oxide (NO) in human umbilical vein endothelial cells (HUVECs) were examined. The production of endothelin-1 and nitric oxide in culture medium was measured using enzyme-linked immunosorbent assay (ELISA) and the Griess method, respectively. Endothelin-1 and endothelial nitric oxide synthase (eNOS) mRNA expression were investigated by real-time quantitative reverse transcriptase/polymerase chain reaction (RT-PCR). Ursodeoxycholic acid (30-1000 microM) inhibited endothelin-1 production in a concentration-dependent manner, and ursodeoxycholic acid at concentrations higher than 300 microM increased nitric oxide production in culture medium. The conjugates of ursodeoxycholic acid also increased nitric oxide production and decreased endothelin-1 production, which was less effective than ursodeoxycholic acid. N-nitro-L-arginine-mythel-ester (L-NAME), a nitric oxide synthase (NOS) inhibitor, suppressed the ursodeoxycholic acid-induced nitric oxide production, but it did not antagonize the inhibitory effects of ursodeoxycholic acid on endothelin-1 production. Ursodeoxycholic acid also induced a concentration-dependent decrease in endothelin-1 mRNA expression without significant changes in eNOS mRNA expression. These results provide novel evidence that ursodeoxycholic acid inhibits endothelin-1 production in human endothelial cells, but nitric oxide is not responsible for the inhibitory effect of ursodeoxycholic acid on endothelin-1. Thus, ursodeoxycholic acid therapy may prevent the development of several pathogenesis such as portal hypertension observed in patients with cirrhosis due to the improvement of endothelial function.
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Affiliation(s)
- Ji Ma
- Department of Cardiovascular Medicine, Respiratory Medicine, and Gastroenterology, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8645, Japan
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