1
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Baldwin SN, Jepps TA, Greenwood IA. Cycling matters: Sex hormone regulation of vascular potassium channels. Channels (Austin) 2023; 17:2217637. [PMID: 37243715 PMCID: PMC10228406 DOI: 10.1080/19336950.2023.2217637] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/07/2023] [Accepted: 05/19/2023] [Indexed: 05/29/2023] Open
Abstract
Sex hormones and the reproductive cycle (estrus in rodents and menstrual in humans) have a known impact on arterial function. In spite of this, sex hormones and the estrus/menstrual cycle are often neglected experimental factors in vascular basic preclinical scientific research. Recent research by our own laboratory indicates that cyclical changes in serum concentrations of sex -hormones across the rat estrus cycle, primary estradiol, have significant consequences for the subcellular trafficking and function of KV. Vascular potassium channels, including KV, are essential components of vascular reactivity. Our study represents a small part of a growing field of literature aimed at determining the role of sex hormones in regulating arterial ion channel function. This review covers key findings describing the current understanding of sex hormone regulation of vascular potassium channels, with a focus on KV channels. Further, we highlight areas of research where the estrus cycle should be considered in future studies to determine the consequences of physiological oscillations in concentrations of sex hormones on vascular potassium channel function.
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Affiliation(s)
- Samuel N Baldwin
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas A Jepps
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Iain A Greenwood
- Vascular Biology Research Centre, Institute of Molecular and Clinical Sciences, St George’s University of London, London, UK
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2
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Här K, Lysenko NN, Dimitrova D, Schlüter T, Zavaritskaya O, Kamkin AG, Mladenov M, Grisk O, Köhler R, Gagov H, Schubert R. Kv2.1 Channels Prevent Vasomotion and Safeguard Myogenic Reactivity in Rat Small Superior Cerebellar Arteries. Cells 2023; 12:1989. [PMID: 37566068 PMCID: PMC10416909 DOI: 10.3390/cells12151989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 07/27/2023] [Accepted: 07/29/2023] [Indexed: 08/12/2023] Open
Abstract
Vascular smooth muscle voltage-gated potassium (Kv) channels have been proposed to contribute to myogenic autoregulation. Surprisingly, in initial experiments, we observed that the Kv2 channel inhibitor stromatoxin induced vasomotion without affecting myogenic tone. Thus, we tested the hypothesis that Kv2 channels contribute to myogenic autoregulation by fine-tuning the myogenic response. Expression of Kv2 channel mRNA was determined using real-time PCR and 'multiplex' single-cell RT-PCR. Potassium currents were measured using the patch-clamp technique. Contractile responses of intact arteries were studied using isobaric myography. Expression of Kv2.1 but not Kv2.2 channels was detected in intact rat superior cerebellar arteries and in single smooth muscle cells. Stromatoxin, a high-affinity inhibitor of Kv2 channels, reduced smooth muscle Kv currents by 61% at saturating concentrations (EC50 36 nmol/L). Further, stromatoxin (10-100 nmol/L) induced pronounced vasomotion in 48% of the vessels studied. In vessels not exhibiting vasomotion, stromatoxin did not affect myogenic reactivity. Notably, in vessels exhibiting stromatoxin-induced vasomotion, pressure increases evoked two effects: First, they facilitated the occurrence of random vasodilations and/or vasoconstrictions, disturbing the myogenic response (24% of the vessels). Second, they modified the vasomotion by decreasing its amplitude and increasing its frequency, thereby destabilizing myogenic tone (76% of the vessels). Our study demonstrates that (i) Kv2.1 channels are the predominantly expressed Kv channels in smooth muscle cells of rat superior cerebellar arteries, and (ii) Kv2.1 channels provide a novel type of negative feedback mechanism in myogenic autoregulation by preventing vasomotion and thereby safeguarding the myogenic response.
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Affiliation(s)
- Kristina Här
- European Center of Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Natalia N. Lysenko
- European Center of Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
- Department of Physiology, N. I. Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Daniela Dimitrova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
| | - Torsten Schlüter
- Institute of Physiology, Universitätsmedizin Greifswald, 17475 Greifswald, Germany
| | - Olga Zavaritskaya
- European Center of Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
| | - Andrej G. Kamkin
- Department of Physiology, N. I. Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Mitko Mladenov
- Department of Physiology, N. I. Pirogov Russian National Research Medical University, 117997 Moscow, Russia
- Institute of Biology, Faculty of Natural Sciences and Mathematics, University of Ss. Cyril and Methodius, 1000 Skopje, North Macedonia
| | - Olaf Grisk
- Institute of Physiology, Brandenburg Medical School Theodor Fontane, 16816 Neuruppin, Germany
| | - Ralf Köhler
- ARAID-IACS, UIT University Hospital Miguel Servet, 50009 Zaragoza, Spain
| | - Hristo Gagov
- Department of Animal and Human Physiology, Faculty of Biology, Sofia University ‘St. Kliment Ohridski’, 1164 Sofia, Bulgaria
| | - Rudolf Schubert
- European Center of Angioscience (ECAS), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany
- Physiology, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Universitätsstrasse 2, 86159 Augsburg, Germany
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3
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Davis MJ, Earley S, Li YS, Chien S. Vascular mechanotransduction. Physiol Rev 2023; 103:1247-1421. [PMID: 36603156 PMCID: PMC9942936 DOI: 10.1152/physrev.00053.2021] [Citation(s) in RCA: 43] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 09/26/2022] [Accepted: 10/04/2022] [Indexed: 01/07/2023] Open
Abstract
This review aims to survey the current state of mechanotransduction in vascular smooth muscle cells (VSMCs) and endothelial cells (ECs), including their sensing of mechanical stimuli and transduction of mechanical signals that result in the acute functional modulation and longer-term transcriptomic and epigenetic regulation of blood vessels. The mechanosensors discussed include ion channels, plasma membrane-associated structures and receptors, and junction proteins. The mechanosignaling pathways presented include the cytoskeleton, integrins, extracellular matrix, and intracellular signaling molecules. These are followed by discussions on mechanical regulation of transcriptome and epigenetics, relevance of mechanotransduction to health and disease, and interactions between VSMCs and ECs. Throughout this review, we offer suggestions for specific topics that require further understanding. In the closing section on conclusions and perspectives, we summarize what is known and point out the need to treat the vasculature as a system, including not only VSMCs and ECs but also the extracellular matrix and other types of cells such as resident macrophages and pericytes, so that we can fully understand the physiology and pathophysiology of the blood vessel as a whole, thus enhancing the comprehension, diagnosis, treatment, and prevention of vascular diseases.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Scott Earley
- Department of Pharmacology, University of Nevada, Reno, Nevada
| | - Yi-Shuan Li
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
- Department of Medicine, University of California, San Diego, California
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4
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Seo MS, An JR, Heo R, Kang M, Park S, Mun SY, Park H, Han ET, Han JH, Chun W, Song G, Park WS. The inhibitory effects of pimozide, an antipsychotic drug, on voltage-gated K + channels in rabbit coronary arterial smooth muscle cells. Drug Chem Toxicol 2023; 46:271-280. [PMID: 35317682 DOI: 10.1080/01480545.2021.2021932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Pimozide is an antipsychotic drug used to treat chronic psychosis, such as Tourette's syndrome. Despite its widespread clinical use, pimozide can cause unexpected adverse effects, including arrhythmias. However, the adverse effects of pimozide on vascular K+ channels have not yet been determined. Therefore, we investigated the effects of pimozide on voltage-gated K+ (Kv) channels in rabbit coronary arterial smooth muscle cells. Pimozide concentration-dependently inhibited the Kv currents with an IC50 value of 1.78 ± 0.17 μM and a Hill coefficient of 0.90 ± 0.05. The inhibitory effect on the Kv current by pimozide was highly voltage-dependent in the voltage range of Kv channel activation, and additive inhibition of the Kv current by pimozide was observed in the full activation voltage range. The decay rate of inactivation was significantly accelerated by pimozide. Pimozide shifted the inactivation curve to a more negative potential. The recovery time constant from inactivation increased in the presence of pimozide. Furthermore, pimozide-induced inhibition of the Kv current was augmented by applying train pulses. Although pretreatment with the Kv2.1 subtype inhibitor guangxitoxin and the Kv7 subtype inhibitor linopirdine did not alter the degree of pimozide-induced inhibition of the Kv currents, pretreatment with the Kv1.5 channel inhibitor DPO-1 reduced the inhibitory effects of pimozide on Kv currents. Pimozide induced membrane depolarization. We conclude that pimozide inhibits Kv currents in voltage-, time-, and use (state)-dependent manners. Furthermore, the major Kv channel target of pimozide is the Kv1.5 channel.
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Affiliation(s)
- Mi Seon Seo
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Jin Ryeol An
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Ryeon Heo
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Minji Kang
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Seojin Park
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Seo-Yeong Mun
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Hongzoo Park
- Department of Urology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Jin-Hee Han
- Department of Medical Environmental Biology and Tropical Medicine, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Wanjoo Chun
- Department of Pharmacology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Geehyun Song
- Department of Urology, Kangwon National University School of Medicine, Chuncheon, South Korea
| | - Won Sun Park
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, South Korea
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5
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Seo MS, An JR, Jung HS, Kang M, Heo R, Han ET, Yang SR, Park H, Jung WK, Choi IW, Bae YM, Na SH, Park WS. Suppression of voltage-gated K + channels by darifenacin in coronary arterial smooth muscle cells. Eur J Pharmacol 2020; 891:173707. [PMID: 33137332 DOI: 10.1016/j.ejphar.2020.173707] [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: 06/18/2020] [Revised: 10/22/2020] [Accepted: 10/29/2020] [Indexed: 10/23/2022]
Abstract
Darifenacin, an anticholinergic agent, has been used to treat overactive bladder syndrome. Despite its extensive clinical use, there is little information about the effect of darifenacin on vascular ion channels, specifically K+ channels. This study aimed to investigate the effect of the anti-muscarinic drug darifenacin on voltage-gated K+ (Kv) channels, vascular contractility, and coronary blood flow in rabbit coronary arteries. We used the whole-cell patch-clamp technique to evaluate the effect of darifenacin on Kv channels. Darifenacin inhibited the Kv current in a concentration-dependent manner. Applying 1 μM darifenacin shifted the activation and inactivation curves toward a more positive and negative potential, respectively. Darifenacin slowed the time constants of recovery from inactivation. Furthermore, blockade of the Kv current with darifenacin was increased gradually by applying a train of pulses, indicating that darifenacin inhibited Kv currents in a use- (state)-dependent manner. The darifenacin-mediated inhibition of Kv currents was associated with the Kv1.5 subtype, not the Kv2.1 or Kv7 subtype. Applying another anti-muscarinic drug atropine or ipratropium did not affect the Kv current or change the inhibitory effect of darifenacin. Isometric organ bath experiments using isolated coronary arteries were applied to evaluate whether darifenacin-induced inhibition of the Kv channel causes vasocontraction. Darifenacin substantially induced vasocontraction. Furthermore, darifenacin caused membrane depolarization and decreased coronary blood flow. From these results, we concluded that darifenacin inhibits the Kv currents in concentration- and use- (state)-dependent manners. Inhibition of the Kv current with darifenacin occurred by shifting the steady-state activation and inactivation curves regardless of its anti-muscarinic effect.
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Affiliation(s)
- Mi Seon Seo
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Jin Ryeol An
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Hee Seok Jung
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Minji Kang
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Ryeon Heo
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Se-Ran Yang
- Department of Thoracic and Cardiovascular Surgery, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Hongzoo Park
- Department of Urology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea
| | - Won-Kyo Jung
- Department of Biomedical Engineering, and Center for Marine-Integrated Biomedical Technology (BK21 Plus), Pukyong National University, Busan, 48513, South Korea
| | - Il-Whan Choi
- Department of Microbiology, College of Medicine, Inje University, Busan, 48516, South Korea
| | - Young Min Bae
- Department of Physiology, Konkuk University School of Medicine, Chungju, 27478, South Korea
| | - Sung Hun Na
- Department of Obstetrics and Gynecology, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea.
| | - Won Sun Park
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon, 24341, South Korea.
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6
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Quelhas P, Baltazar G, Cairrao E. The Neurovascular Unit: Focus on the Regulation of Arterial Smooth Muscle Cells. Curr Neurovasc Res 2020; 16:502-515. [PMID: 31738142 DOI: 10.2174/1567202616666191026122642] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 09/01/2019] [Accepted: 09/20/2019] [Indexed: 02/08/2023]
Abstract
The neurovascular unit is a physiological unit present in the brain, which is constituted by elements of the nervous system (neurons and astrocytes) and the vascular system (endothelial and mural cells). This unit is responsible for the homeostasis and regulation of cerebral blood flow. There are two major types of mural cells in the brain, pericytes and smooth muscle cells. At the arterial level, smooth muscle cells are the main components that wrap around the outside of cerebral blood vessels and the major contributors to basal tone maintenance, blood pressure and blood flow distribution. They present several mechanisms by which they regulate both vasodilation and vasoconstriction of cerebral blood vessels and their regulation becomes even more important in situations of injury or pathology. In this review, we discuss the main regulatory mechanisms of brain smooth muscle cells and their contributions to the correct brain homeostasis.
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Affiliation(s)
- Patrícia Quelhas
- CICS-UBI - Centro de Investigacao em Ciencias da Saude, University of Beira Interior, 6200-506 Covilha, Portugal
| | - Graça Baltazar
- CICS-UBI - Centro de Investigacao em Ciencias da Saude, University of Beira Interior, 6200-506 Covilha, Portugal
| | - Elisa Cairrao
- CICS-UBI - Centro de Investigacao em Ciencias da Saude, University of Beira Interior, 6200-506 Covilha, Portugal
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7
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Quelhas P, Baltazar G, Cairrao E. Characterization of culture from smooth muscle cells isolated from rat middle cerebral arteries. Tissue Cell 2020; 66:101400. [PMID: 32933705 DOI: 10.1016/j.tice.2020.101400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 06/09/2020] [Accepted: 06/26/2020] [Indexed: 02/07/2023]
Abstract
Although human brain represents only 2% of the body mass, it uses around 20 % of the organism energy. Due to the brain's limited energy storage, the oxygen and glucose necessary to support brain functions depends on the correct blood supply. The main components of the arteries are smooth muscle cells, which are considered the main regulators of vascular tone and blood flow distribution. The information currently available on the functioning of the cerebral arteries and their cell constituents is extremely scarce. Thus, the aim of this work was to develop an in vitro model of smooth muscle cells derived from rat middle cerebral artery. Explants were collected from rat middle cerebral artery and adhered to collagen-coated culture dishes. Immunocytochemical analysis showed that the cells present in the culture expressed α-actin, a protein characteristic of the contractile phenotype of these cells. In addition, these cells did not express the endothelial marker, vWF. To evaluate the functionality of these cells the response to contractile agents, serotonin and noradrenaline, and to relaxing agent, sodium nitroprusside was determine by Planar Cell Surface Area analysis. Together the data obtained show that the cell culture obtained through the procedure described resulted in cells presenting the markers characteristic of smooth muscle cells and maintaining the usual contractile response, indicating that the cells obtained through this may be used as a model for characterization and study of functional behavior of the middle cerebral artery, as well as interaction studies between vascular and neuronal system.
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Affiliation(s)
- Patricia Quelhas
- CICS-UBI - Centro de Investigação em Ciências da Saúde, University of Beira Interior, 6200-506 Covilhã, Portugal
| | - Graça Baltazar
- CICS-UBI - Centro de Investigação em Ciências da Saúde, University of Beira Interior, 6200-506 Covilhã, Portugal
| | - Elisa Cairrao
- CICS-UBI - Centro de Investigação em Ciências da Saúde, University of Beira Interior, 6200-506 Covilhã, Portugal.
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8
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Levy BI, Heusch G, Camici PG. The many faces of myocardial ischaemia and angina. Cardiovasc Res 2020; 115:1460-1470. [PMID: 31228187 DOI: 10.1093/cvr/cvz160] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/25/2019] [Accepted: 06/17/2019] [Indexed: 12/13/2022] Open
Abstract
Obstructive disease of the epicardial coronary arteries is the main cause of angina. However, a number of patients with anginal symptoms have normal coronaries or non-obstructive coronary artery disease (CAD) despite electrocardiographic evidence of ischaemia during stress testing. In addition to limited microvascular vasodilator capacity, the coronary microcirculation of these patients is particularly sensitive to vasoconstrictor stimuli, in a condition known as microvascular angina. This review briefly summarizes the determinants and control of coronary blood flow (CBF) and myocardial perfusion. It subsequently analyses the mechanisms responsible for transient myocardial ischaemia: obstructive CAD, coronary spasm and coronary microvascular dysfunction in the absence of epicardial coronary lesions, and variable combinations of structural anomalies, impaired endothelium-dependent and/or -independent vasodilation, and enhanced perception of pain. Lastly, we exemplify mechanism of angina during tachycardia. Distal to a coronary stenosis, coronary dilator reserve is already recruited and can be nearly exhausted at rest distal to a severe stenosis. Increased heart rate reduces the duration of diastole and thus CBF when metabolic vasodilation is no longer able to increase CBF. The increase in myocardial oxygen consumption and resulting metabolic vasodilation in adjacent myocardium without stenotic coronary arteries further acts to divert blood flow away from the post-stenotic coronary vascular bed through collaterals.
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Affiliation(s)
- Bernard I Levy
- Inserm U970 and Vessels and Blood Institute, 8 Rue Guy Patin, Paris, France
| | - Gerd Heusch
- Institute for Pathophysiology, West German Heart and Vascular Center, Universitätsklinikum Essen, Essen, Germany
| | - Paolo G Camici
- Vita Salute University and San Raffaele Hospital, Milan, Italy
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9
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Rhee SW, Rusch NJ. Molecular determinants of beta-adrenergic signaling to voltage-gated K + channels in the cerebral circulation. Microcirculation 2018; 25. [PMID: 29072364 DOI: 10.1111/micc.12425] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 10/19/2017] [Indexed: 12/14/2022]
Abstract
Voltage-gated K+ (Kv ) channels are major determinants of membrane potential in vascular smooth muscle cells (VSMCs) and regulate the diameter of small cerebral arteries and arterioles. However, the intracellular structures that govern the expression and function of vascular Kv channels are poorly understood. Scaffolding proteins including postsynaptic density 95 (PSD95) recently were identified in rat cerebral VSMCs. Primarily characterized in neurons, the PSD95 scaffold has more than 50 known binding partners, and it can mediate macromolecular signaling between cell-surface receptors and ion channels. In cerebral arteries, Shaker-type Kv 1 channels appear to associate with the PSD95 molecular scaffold, and PSD95 is required for the normal expression and vasodilator influence of members of this K+ channel gene family. Furthermore, recent findings suggest that the β1-subtype adrenergic receptor is expressed in cerebral VSMCs and forms a functional vasodilator complex with Kv 1 channels on the PSD95 scaffold. Activation of β1-subtype adrenergic receptors in VSMCs enables protein kinase A-dependent phosphorylation and opening of Kv 1 channels in the PSD95 complex; the subsequent K+ efflux mediates membrane hyperpolarization and vasodilation of small cerebral arteries. Early evidence from other studies suggests that other families of Kv channels and scaffolding proteins are expressed in VSMCs. Future investigations into these macromolecular complexes that modulate the expression and function of Kv channels may reveal unknown signaling cascades that regulate VSMC excitability and provide novel targets for ion channel-based medications to optimize vascular tone.
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Affiliation(s)
- Sung W Rhee
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Nancy J Rusch
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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10
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Koide M, Moshkforoush A, Tsoukias NM, Hill-Eubanks DC, Wellman GC, Nelson MT, Dabertrand F. The yin and yang of K V channels in cerebral small vessel pathologies. Microcirculation 2018; 25. [PMID: 29247493 DOI: 10.1111/micc.12436] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 12/08/2017] [Indexed: 12/14/2022]
Abstract
Cerebral SVDs encompass a group of genetic and sporadic pathological processes leading to brain lesions, cognitive decline, and stroke. There is no specific treatment for SVDs, which progress silently for years before becoming clinically symptomatic. Here, we examine parallels in the functional defects of PAs in CADASIL, a monogenic form of SVD, and in response to SAH, a common type of hemorrhagic stroke that also targets the brain microvasculature. Both animal models exhibit dysregulation of the voltage-gated potassium channel, KV 1, in arteriolar myocytes, an impairment that compromises responses to vasoactive stimuli and impacts CBF autoregulation and local dilatory responses to neuronal activity (NVC). However, the extent to which this channelopathy-like defect ultimately contributes to these pathologies is unknown. Combining experimental data with computational modeling, we describe the role of KV 1 channels in the regulation of myocyte membrane potential at rest and during the modest increase in extracellular potassium associated with NVC. We conclude that PA resting membrane potential and myogenic tone depend strongly on KV 1.2/1.5 channel density, and that reciprocal changes in KV channel density in CADASIL and SAH produce opposite effects on extracellular potassium-mediated dilation during NVC.
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Affiliation(s)
- Masayo Koide
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - Arash Moshkforoush
- Department of Biomedical Engineering, Florida International University, Miami, FL, USA
| | - Nikolaos M Tsoukias
- Department of Biomedical Engineering, Florida International University, Miami, FL, USA
| | | | - George C Wellman
- Department of Pharmacology, University of Vermont, Burlington, VT, USA
| | - Mark T Nelson
- Department of Pharmacology, University of Vermont, Burlington, VT, USA.,Institute of Cardiovascular Sciences, University of Manchester, Manchester, UK
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11
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Jackson WF. K V channels and the regulation of vascular smooth muscle tone. Microcirculation 2018; 25. [PMID: 28985443 DOI: 10.1111/micc.12421] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 10/01/2017] [Indexed: 12/31/2022]
Abstract
VSMCs in resistance arteries and arterioles express a diverse array of KV channels with members of the KV 1, KV 2 and KV 7 families being particularly important. Members of the KV channel family: (i) are highly expressed in VSMCs; (ii) are active at the resting membrane potential of VSMCs in vivo (-45 to -30 mV); (iii) contribute to the negative feedback regulation of VSMC membrane potential and myogenic tone; (iv) are activated by cAMP-related vasodilators, hydrogen sulfide and hydrogen peroxide; (v) are inhibited by increases in intracellular Ca2+ and vasoconstrictors that signal through Gq -coupled receptors; (vi) are involved in the proliferative phenotype of VSMCs; and (vii) are modulated by diseases such as hypertension, obesity, the metabolic syndrome and diabetes. Thus, KV channels participate in every aspect of the regulation of VSMC function in both health and disease.
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Affiliation(s)
- William F Jackson
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, USA
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12
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Ranchoux B, Harvey LD, Ayon RJ, Babicheva A, Bonnet S, Chan SY, Yuan JXJ, Perez VDJ. Endothelial dysfunction in pulmonary arterial hypertension: an evolving landscape (2017 Grover Conference Series). Pulm Circ 2018; 8:2045893217752912. [PMID: 29283043 PMCID: PMC5798691 DOI: 10.1177/2045893217752912] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 12/18/2017] [Indexed: 02/06/2023] Open
Abstract
Endothelial dysfunction is a major player in the development and progression of vascular pathology in pulmonary arterial hypertension (PAH), a disease associated with small vessel loss and obstructive vasculopathy that leads to increased pulmonary vascular resistance, subsequent right heart failure, and premature death. Over the past ten years, there has been tremendous progress in our understanding of pulmonary endothelial biology as it pertains to the genetic and molecular mechanisms that orchestrate the endothelial response to direct or indirect injury, and how their dysregulation can contribute to the pathogenesis of PAH. As one of the major topics included in the 2017 Grover Conference Series, discussion centered on recent developments in four areas of pulmonary endothelial biology: (1) angiogenesis; (2) endothelial-mesenchymal transition (EndMT); (3) epigenetics; and (4) biology of voltage-gated ion channels. The present review will summarize the content of these discussions and provide a perspective on the most promising aspects of endothelial dysfunction that may be amenable for therapeutic development.
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Affiliation(s)
| | - Lloyd D. Harvey
- University of Pittsburgh Vascular Medicine Institute Division of Cardiology, Pittsburgh, PA, USA
| | - Ramon J. Ayon
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Aleksandra Babicheva
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | | | - Stephen Y. Chan
- University of Pittsburgh Vascular Medicine Institute Division of Cardiology, Pittsburgh, PA, USA
| | - Jason X.-J. Yuan
- Division of Translational and Regenerative Medicine, The University of Arizona College of Medicine, Tucson, AZ, USA
| | - Vinicio de Jesus Perez
- Division of Pulmonary and Critical Care Medicine, Stanford University Medical Center, Stanford, CA, USA
- The Vera Moulton Wall Center for Pulmonary Vascular Medicine, Stanford University Medical Center, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University Medical Center, Stanford, CA, USA
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13
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Olschewski A, Veale EL, Nagy BM, Nagaraj C, Kwapiszewska G, Antigny F, Lambert M, Humbert M, Czirják G, Enyedi P, Mathie A. TASK-1 (KCNK3) channels in the lung: from cell biology to clinical implications. Eur Respir J 2017; 50:50/5/1700754. [PMID: 29122916 DOI: 10.1183/13993003.00754-2017] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 08/05/2017] [Indexed: 12/18/2022]
Abstract
TWIK-related acid-sensitive potassium channel 1 (TASK-1 encoded by KCNK3) belongs to the family of two-pore domain potassium channels. This gene subfamily is constitutively active at physiological resting membrane potentials in excitable cells, including smooth muscle cells, and has been particularly linked to the human pulmonary circulation. TASK-1 channels are sensitive to a wide array of physiological and pharmacological mediators that affect their activity such as unsaturated fatty acids, extracellular pH, hypoxia, anaesthetics and intracellular signalling pathways. Recent studies show that modulation of TASK-1 channels, either directly or indirectly by targeting their regulatory mechanisms, has the potential to control pulmonary arterial tone in humans. Furthermore, mutations in KCNK3 have been identified as a rare cause of both familial and idiopathic pulmonary arterial hypertension. This review summarises our current state of knowledge of the functional role of TASK-1 channels in the pulmonary circulation in health and disease, with special emphasis on current advancements in the field.
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Affiliation(s)
- Andrea Olschewski
- Ludwig Boltzmann Institute for Lung Vascular Research Graz, Graz, Austria .,Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Emma L Veale
- Medway School of Pharmacy, University of Kent, Central Avenue, Chatham Maritime, UK
| | - Bence M Nagy
- Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Chandran Nagaraj
- Ludwig Boltzmann Institute for Lung Vascular Research Graz, Graz, Austria.,Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Grazyna Kwapiszewska
- Ludwig Boltzmann Institute for Lung Vascular Research Graz, Graz, Austria.,Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Fabrice Antigny
- Univ. Paris-Sud, Faculté de Médecine, Kremlin-Bicêtre, France.,AP-HP, Centre de Référence de l'Hypertension Pulmonaire Sévère, Département Hospitalo-Universitaire (DHU) Thorax Innovation, Service de Pneumologie et Réanimation Respiratoire, Hôpital de Bicêtre, Le Kremlin-Bicêtre, France.,UMRS 999, INSERM and Univ. Paris-Sud, Laboratoire d'Excellence (LabEx) en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Hôpital-Marie-Lannelongue, Le Plessis Robinson, France
| | - Mélanie Lambert
- Univ. Paris-Sud, Faculté de Médecine, Kremlin-Bicêtre, France.,AP-HP, Centre de Référence de l'Hypertension Pulmonaire Sévère, Département Hospitalo-Universitaire (DHU) Thorax Innovation, Service de Pneumologie et Réanimation Respiratoire, Hôpital de Bicêtre, Le Kremlin-Bicêtre, France.,UMRS 999, INSERM and Univ. Paris-Sud, Laboratoire d'Excellence (LabEx) en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Hôpital-Marie-Lannelongue, Le Plessis Robinson, France
| | - Marc Humbert
- Univ. Paris-Sud, Faculté de Médecine, Kremlin-Bicêtre, France.,AP-HP, Centre de Référence de l'Hypertension Pulmonaire Sévère, Département Hospitalo-Universitaire (DHU) Thorax Innovation, Service de Pneumologie et Réanimation Respiratoire, Hôpital de Bicêtre, Le Kremlin-Bicêtre, France.,UMRS 999, INSERM and Univ. Paris-Sud, Laboratoire d'Excellence (LabEx) en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Hôpital-Marie-Lannelongue, Le Plessis Robinson, France
| | - Gábor Czirják
- Dept of Physiology, Semmelweis University, Budapest, Hungary
| | - Péter Enyedi
- Dept of Physiology, Semmelweis University, Budapest, Hungary
| | - Alistair Mathie
- Medway School of Pharmacy, University of Kent, Central Avenue, Chatham Maritime, UK
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14
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Al-Owais MM, Hettiarachchi NT, Boyle JP, Scragg JL, Elies J, Dallas ML, Lippiat JD, Steele DS, Peers C. Multiple mechanisms mediating carbon monoxide inhibition of the voltage-gated K + channel Kv1.5. Cell Death Dis 2017; 8:e3163. [PMID: 29095440 PMCID: PMC5775415 DOI: 10.1038/cddis.2017.568] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 12/13/2022]
Abstract
The voltage-gated K+ channel has key roles in the vasculature and in atrial excitability and contributes to apoptosis in various tissues. In this study, we have explored its regulation by carbon monoxide (CO), a product of the cytoprotective heme oxygenase enzymes, and a recognized toxin. CO inhibited recombinant Kv1.5 expressed in HEK293 cells in a concentration-dependent manner that involved multiple signalling pathways. CO inhibition was partially reversed by superoxide dismutase mimetics and by suppression of mitochondrial reactive oxygen species. CO also elevated intracellular nitric oxide (NO) levels. Prevention of NO formation also partially reversed CO inhibition of Kv1.5, as did inhibition of soluble guanylyl cyclase. CO also elevated intracellular peroxynitrite levels, and a peroxynitrite scavenger markedly attenuated the ability of CO to inhibit Kv1.5. CO caused nitrosylation of Kv1.5, an effect that was also observed in C331A and C346A mutant forms of the channel, which had previously been suggested as nitrosylation sites within Kv1.5. Augmentation of Kv1.5 via exposure to hydrogen peroxide was fully reversed by CO. Native Kv1.5 recorded in HL-1 murine atrial cells was also inhibited by CO. Action potentials recorded in HL-1 cells were increased in amplitude and duration by CO, an effect mimicked and occluded by pharmacological inhibition of Kv1.5. Our data indicate that Kv1.5 is a target for modulation by CO via multiple mechanisms. This regulation has important implications for diverse cellular functions, including excitability, contractility and apoptosis.
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Affiliation(s)
- Moza M Al-Owais
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Nishani T Hettiarachchi
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - John P Boyle
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Jason L Scragg
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Jacobo Elies
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Mark L Dallas
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Jon D Lippiat
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Derek S Steele
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Chris Peers
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
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15
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Ohanyan V, Yin L, Bardakjian R, Kolz C, Enrick M, Hakobyan T, Luli J, Graham K, Khayata M, Logan S, Kmetz J, Chilian WM. Kv1.3 channels facilitate the connection between metabolism and blood flow in the heart. Microcirculation 2017; 24:10.1111/micc.12334. [PMID: 28504408 PMCID: PMC5433265 DOI: 10.1111/micc.12334] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 10/23/2016] [Accepted: 11/01/2016] [Indexed: 12/17/2022]
Abstract
The connection between metabolism and flow in the heart, metabolic dilation, is essential for cardiac function. We recently found redox-sensitive Kv1.5 channels play a role in coronary metabolic dilation; however, more than one ion channel likely plays a role in this process as animals null for these channels still showed limited coronary metabolic dilation. Accordingly, we examined the role of another Kv1 family channel, the energetically linked Kv1.3 channel, in coronary metabolic dilation. We measured myocardial blood flow (contrast echocardiography) during norepinephrine-induced increases in cardiac work (heart rate x mean arterial pressure) in WT, WT mice given correolide (preferential Kv1.3 antagonist), and Kv1.3-null mice (Kv1.3-/- ). We also measured relaxation of isolated small arteries mounted in a myograph. During increased cardiac work, myocardial blood flow was attenuated in Kv1.3-/- and in correolide-treated mice. In isolated vessels from Kv1.3-/- mice, relaxation to H2 O2 was impaired (vs WT), but responses to adenosine and acetylcholine were equivalent to WT. Correolide reduced dilation to adenosine and acetylcholine in WT and Kv1.3-/- , but had no effect on H2 O2 -dependent dilation in vessels from Kv1.3-/- mice. We conclude that Kv1.3 channels participate in the connection between myocardial blood flow and cardiac metabolism.
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Affiliation(s)
- Vahagn Ohanyan
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Liya Yin
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | | | - Christopher Kolz
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Molly Enrick
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Tatevik Hakobyan
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Jordan Luli
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Kathleen Graham
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | | | - Suzanna Logan
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - John Kmetz
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
| | - William M Chilian
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
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16
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Tykocki NR, Boerman EM, Jackson WF. Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles. Compr Physiol 2017; 7:485-581. [PMID: 28333380 DOI: 10.1002/cphy.c160011] [Citation(s) in RCA: 212] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont, Burlington, Vermont, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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17
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Tsvetkov D, Tano JY, Kassmann M, Wang N, Schubert R, Gollasch M. The Role of DPO-1 and XE991-Sensitive Potassium Channels in Perivascular Adipose Tissue-Mediated Regulation of Vascular Tone. Front Physiol 2016; 7:335. [PMID: 27540364 PMCID: PMC4973012 DOI: 10.3389/fphys.2016.00335] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 07/20/2016] [Indexed: 11/13/2022] Open
Abstract
The anti-contractile effect of perivascular adipose tissue (PVAT) is an important mechanism in the modulation of vascular tone in peripheral arteries. Recent evidence has implicated the XE991-sensitive voltage-gated KV (KCNQ) channels in the regulation of arterial tone by PVAT. However, until now the in vivo pharmacology of the involved vascular KV channels with regard to XE991 remains undetermined, since XE991 effects may involve Ca(2+) activated BKCa channels and/or voltage-dependent KV1.5 channels sensitive to diphenyl phosphine oxide-1 (DPO-1). In this study, we tested whether KV1.5 channels are involved in the control of mesenteric arterial tone and its regulation by PVAT. Our study was also aimed at extending our current knowledge on the in situ vascular pharmacology of DPO-1 and XE991 regarding KV1.5 and BKCa channels, in helping to identify the nature of K(+) channels that could contribute to PVAT-mediated relaxation. XE991 at 30 μM reduced the anti-contractile response of PVAT, but had no effects on vasocontraction induced by phenylephrine (PE) in the absence of PVAT. Similar effects were observed for XE991 at 0.3 μM, which is known to almost completely inhibit mesenteric artery VSMC KV currents. 30 μM XE991 did not affect BKCa currents in VSMCs. Kcna5 (-/-) arteries and wild-type arteries incubated with 1 μM DPO-1 showed normal vasocontractions in response to PE in the presence and absence of PVAT. KV current density and inhibition by 30 μM XE991 were normal in mesenteric artery VSMCs isolated from Kcna5 (-/-) mice. We conclude that KV channels are involved in the control of arterial vascular tone by PVAT. These channels are present in VSMCs and very potently inhibited by the KCNQ channel blocker XE991. BKCa channels and/or DPO-1 sensitive KV1.5 channels in VSMCs are not the downstream mediators of the XE991 effects on PVAT-dependent arterial vasorelaxation. Further studies will need to be undertaken to examine the role of other KV channels in the phenomenon.
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Affiliation(s)
- Dmitry Tsvetkov
- Experimental and Clinical Research Center, A Joint Cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association of German Research Centres Berlin, Germany
| | - Jean-Yves Tano
- Experimental and Clinical Research Center, A Joint Cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association of German Research Centres Berlin, Germany
| | - Mario Kassmann
- Experimental and Clinical Research Center, A Joint Cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association of German Research Centres Berlin, Germany
| | - Ning Wang
- Experimental and Clinical Research Center, A Joint Cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association of German Research Centres Berlin, Germany
| | - Rudolf Schubert
- Research Division Cardiovascular Physiology, Centre for Biomedicine and Medical Technology Mannheim, Medical Faculty Mannheim of the University Heidelberg Mannheim, Germany
| | - Maik Gollasch
- Experimental and Clinical Research Center, A Joint Cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association of German Research CentresBerlin, Germany; Medical Clinic for Nephrology and Internal Intensive Care, Charité University MedicineBerlin, Germany
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18
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Arsyad A, Dobson GP. Adenosine relaxation in isolated rat aortic rings and possible roles of smooth muscle Kv channels, KATP channels and A2a receptors. BMC Pharmacol Toxicol 2016; 17:23. [PMID: 27211886 PMCID: PMC4876563 DOI: 10.1186/s40360-016-0067-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 04/29/2016] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND An area of ongoing controversy is the role adenosine to regulate vascular tone in conduit vessels that regulate compliance, and the role of nitric oxide (NO), potassium channels and receptor subtypes involved. The aim of our study was to investigate adenosine relaxation in rat thoracic aortic rings, and the effect of inhibitors of NO, prostanoids, Kv, KATP channels, and A2a and A2b receptors. METHODS Aortic rings were freshly harvested from adult male Sprague Dawley rats and equilibrated in an organ bath containing oxygenated, modified Krebs-Henseleit solution, 11 mM glucose, pH 7.4, 37 °C. Isolated rings were pre-contracted sub-maximally with 0.3 μM norepinephrine (NE), and the effect of increasing concentrations of adenosine (1 to 1000 μM) were examined. The drugs L-NAME, indomethacin, 4-aminopyridine (4-AP), glibenclamide, 5-hydroxydecanoate, ouabain, 8-(3-chlorostyryl) caffeine and PSB-0788 were examined in intact and denuded rings. Rings were tested for viability after each experiment. RESULTS Adenosine induced a dose-dependent, triphasic relaxation response, and the mechanical removal of the endothelium significantly deceased adenosine relaxation above 10 μM. Interestingly, endothelial removal significantly decreased the responsiveness (defined as % relaxation per μM adenosine) by two-thirds between 10 and 100 μM, but not in the lower (1-10 μM) or higher (>100 μM) ranges. In intact rings, L-NAME significantly reduced relaxation, but not indomethacin. Antagonists of voltage-dependent Kv (4-AP), sarcolemma KATP (glibenclamide) and mitochondrial KATP channels (5-HD) led to significant reductions in relaxation in both intact and denuded rings, with ouabain having little or no effect. Adenosine-induced relaxation appeared to involve the A2a receptor, but not the A2b subtype. CONCLUSIONS It was concluded that adenosine relaxation in NE-precontracted rat aortic rings was triphasic and endothelium-dependent above 10 μM, and relaxation involved endothelial nitric oxide (not prostanoids) and a complex interplay between smooth muscle A2a subtype and voltage-dependent Kv, SarcKATP and MitoKATP channels. The possible in vivo significance of the regulation of arterial compliance to left ventricular function coupling is discussed.
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Affiliation(s)
- Aryadi Arsyad
- Physiology Department, Medical Faculty, Hasanuddin University, Jl. Perintis Kemerdekaan, Km. 10, Tamalanrea, Makassar, 90213, Indonesia
| | - Geoffrey P Dobson
- Heart, Trauma and Sepsis Research Laboratory, Australian Institute of Tropical Health and Medicine, College of Medicine and Dentistry, James Cook University, 1 James Cook Drive, Queensland, 4811, Australia.
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19
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Jackson R, Brennan S, Fielding P, Sims MW, Challiss RAJ, Adlam D, Squire IB, Rainbow RD. Distinct and complementary roles for α and β isoenzymes of PKC in mediating vasoconstrictor responses to acutely elevated glucose. Br J Pharmacol 2016; 173:870-87. [PMID: 26660275 DOI: 10.1111/bph.13399] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 11/23/2015] [Accepted: 11/30/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND AND PURPOSE We investigated the hypothesis that elevated glucose increases contractile responses in vascular smooth muscle and that this enhanced constriction occurs due to the glucose-induced PKC-dependent inhibition of voltage-gated potassium channels. EXPERIMENTAL APPROACH Patch-clamp electrophysiology in rat isolated mesenteric arterial myocytes was performed to investigate the glucose-induced inhibition of voltage-gated potassium (Kv ) current. To determine the effects of glucose in whole vessel, wire myography was performed in rat mesenteric, porcine coronary and human internal mammary arteries. KEY RESULTS Glucose-induced inhibition of Kv was PKC-dependent and could be pharmacologically dissected using PKC isoenzyme-specific inhibitors to reveal a PKCβ-dependent component of Kv inhibition dominating between 0 and 10 mM glucose with an additional PKCα-dependent component becoming evident at concentrations greater than 10 mM. These findings were supported using wire myography in all artery types used, where contractile responses to vessel depolarization and vasoconstrictors were enhanced by increasing bathing glucose concentration, again with evidence for distinct and complementary PKCα/PKCβ-mediated components. CONCLUSIONS AND IMPLICATIONS Our results provide compelling evidence that glucose-induced PKCα/PKCβ-mediated inhibition of Kv current in vascular smooth muscle causes an enhanced constrictor response. Inhibition of Kv current causes a significant depolarization of vascular myocytes leading to marked vasoconstriction. The PKC dependence of this enhanced constrictor response may present a potential therapeutic target for improving microvascular perfusion following percutaneous coronary intervention after myocardial infarction in hyperglycaemic patients.
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Affiliation(s)
- Robert Jackson
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Sean Brennan
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Peter Fielding
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Mark W Sims
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - R A John Challiss
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - David Adlam
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Iain B Squire
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
| | - Richard D Rainbow
- Department of Cardiovascular Sciences, University of Leicester, Glenfield General Hospital, Leicester, UK
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20
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Bocksteins E. Kv5, Kv6, Kv8, and Kv9 subunits: No simple silent bystanders. J Gen Physiol 2016; 147:105-25. [PMID: 26755771 PMCID: PMC4727947 DOI: 10.1085/jgp.201511507] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 12/11/2015] [Indexed: 12/19/2022] Open
Abstract
Members of the electrically silent voltage-gated K(+) (Kv) subfamilies (Kv5, Kv6, Kv8, and Kv9, collectively identified as electrically silent voltage-gated K(+) channel [KvS] subunits) do not form functional homotetrameric channels but assemble with Kv2 subunits into heterotetrameric Kv2/KvS channels with unique biophysical properties. Unlike the ubiquitously expressed Kv2 subunits, KvS subunits show a more restricted expression. This raises the possibility that Kv2/KvS heterotetramers have tissue-specific functions, making them potential targets for the development of novel therapeutic strategies. Here, I provide an overview of the expression of KvS subunits in different tissues and discuss their proposed role in various physiological and pathophysiological processes. This overview demonstrates the importance of KvS subunits and Kv2/KvS heterotetramers in vivo and the importance of considering KvS subunits and Kv2/KvS heterotetramers in the development of novel treatments.
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Affiliation(s)
- Elke Bocksteins
- Laboratory for Molecular Biophysics, Physiology, and Pharmacology, Department for Biomedical Sciences, University of Antwerp, 2610 Antwerp, Belgium
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21
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Fancher IS, Butcher JT, Brooks SD, Rottgen TS, Skaff PR, Frisbee JC, Dick GM. Diphenyl phosphine oxide-1-sensitive K(+) channels contribute to the vascular tone and reactivity of resistance arteries from brain and skeletal muscle. Microcirculation 2016; 22:315-25. [PMID: 25808400 DOI: 10.1111/micc.12201] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 03/17/2015] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Many types of vascular smooth muscle cells exhibit prominent KDR currents. These KDR currents may be mediated, at least in part, by KV1.5 channels, which are sensitive to inhibition by DPO-1. We tested the hypothesis that DPO-1-sensitive KDR channels regulate the tone and reactivity of resistance-sized vessels from rat brain (MCA) and skeletal muscle (GA). METHODS Middle cerebral and gracilis arteries were isolated and subjected to three kinds of experimental analysis: (i) western blot/immunocytochemistry; (ii) patch clamp electrophysiology; and (iii) pressure myography. RESULTS Western blot and immunocytochemistry experiments demonstrated KV1.5 immunoreactivity in arteries and smooth muscle cells isolated from them. Whole-cell patch clamp experiments revealed smooth muscle cells from resistance-sized arteries to possess a KDR current that was blocked by DPO-1. Resistance arteries constricted in response to increasing concentrations of DPO-1. DPO-1 enhanced constrictions to PE and serotonin in gracilis and middle cerebral arteries, respectively. When examining the myogenic response, we found that DPO-1 reduced the diameter at any given pressure. Dilations in response to ACh and SNP were reduced by DPO-1. CONCLUSION We suggest that KV1.5, a DPO-1-sensitive KDR channel, plays a major role in determining microvascular tone and the response to vasoconstrictors and vasodilators.
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Affiliation(s)
- Ibra S Fancher
- Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, West Virginia, USA
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22
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Asano S, Manne NDPK, Nandyala G, Ma B, Selvaraj V, Arvapalli R, Rice KM, Blough ER. Cecal inoculum peritonitis: An alternative model for sepsis vascular dysfunction study. Life Sci 2015; 141:108-18. [PMID: 26417684 DOI: 10.1016/j.lfs.2015.09.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 09/23/2015] [Accepted: 09/24/2015] [Indexed: 01/15/2023]
Abstract
AIMS Sepsis is a life threatening condition that is characterized by the loss of vascular reactivity. The factor(s) responsible for the diminished vascular function seen in sepsis are not well understood. The purpose of this study was to characterize the vascular dysfunction from the rat cecal inoculum (CI) sepsis model using cecal ligation and puncture (CLP), and lipopolysaccharide (LPS) sepsis as reference models. MATERIALS AND METHODS Experiments were performed on isolated aorta from CI, CLP and LPS treated rats using a combination of pharmacological approaches. KEY FINDINGS Phenylephrine (PE)-induced aortic contraction was significantly decreased in each model (p<0.05) and not normalized by L-NAME or indomethacin. The vascular response elicited in the CI model for acetylcholine (Ach) was more similar to that seen in the CLP than the LPS model. The removal of the endothelial layer increased sensitivity to L-NAME (p<0.05) in aortae from CI group. Inhibition of the large conductance Ca(2+)/voltage sensitive K(+) (BKCa) channel did not normalize PE hyporesponsiveness but did abolish sepsis-induced contractile oscillation. Inhibition of the voltage dependent Kv1.5 channel was not able to reverse the vascular hyporesponsiveness, however, inhibition of the ATP dependent (KATP) channel inhibition partially restored the contractile response (p<0.05). Elevation of VCAM expression and aortic structural alternation were observed in each model. SIGNIFICANCE These results suggest that the CI model may be an additional tool that could be used to investigate the mechanisms of vascular hyporesponsiveness in sepsis.
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Affiliation(s)
- Shinichi Asano
- Center for Diagnostic Nanosystems, Marshall University, Huntington, WV, USA; Department of Pharmaceutical Sciences and Research, School of Pharmacy, Marshall University, Huntington, WV, USA.
| | - Nandini D P K Manne
- Center for Diagnostic Nanosystems, Marshall University, Huntington, WV, USA; Department of Pharmaceutical Sciences and Research, School of Pharmacy, Marshall University, Huntington, WV, USA; Department of Public Health, Marshall University, Huntington, WV, USA
| | - Geeta Nandyala
- Center for Diagnostic Nanosystems, Marshall University, Huntington, WV, USA
| | - Bing Ma
- Center for Diagnostic Nanosystems, Marshall University, Huntington, WV, USA; Department of Pharmaceutical Sciences and Research, School of Pharmacy, Marshall University, Huntington, WV, USA
| | - Vellaisamy Selvaraj
- Center for Diagnostic Nanosystems, Marshall University, Huntington, WV, USA; Department of Pharmaceutical Sciences and Research, School of Pharmacy, Marshall University, Huntington, WV, USA
| | | | - Kevin M Rice
- Center for Diagnostic Nanosystems, Marshall University, Huntington, WV, USA
| | - Eric R Blough
- Center for Diagnostic Nanosystems, Marshall University, Huntington, WV, USA; Department of Pharmaceutical Sciences and Research, School of Pharmacy, Marshall University, Huntington, WV, USA; Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, USA
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Ohanyan V, Yin L, Bardakjian R, Kolz C, Enrick M, Hakobyan T, Kmetz J, Bratz I, Luli J, Nagane M, Khan N, Hou H, Kuppusamy P, Graham J, Fu FK, Janota D, Oyewumi MO, Logan S, Lindner JR, Chilian WM. Requisite Role of Kv1.5 Channels in Coronary Metabolic Dilation. Circ Res 2015. [PMID: 26224794 DOI: 10.1161/circresaha.115.306642] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
RATIONALE In the working heart, coronary blood flow is linked to the production of metabolites, which modulate tone of smooth muscle in a redox-dependent manner. Voltage-gated potassium channels (Kv), which play a role in controlling membrane potential in vascular smooth muscle, have certain members that are redox-sensitive. OBJECTIVE To determine the role of redox-sensitive Kv1.5 channels in coronary metabolic flow regulation. METHODS AND RESULTS In mice (wild-type [WT], Kv1.5 null [Kv1.5(-/-)], and Kv1.5(-/-) and WT with inducible, smooth muscle-specific expression of Kv1.5 channels), we measured mean arterial pressure, myocardial blood flow, myocardial tissue oxygen tension, and ejection fraction before and after inducing cardiac stress with norepinephrine. Cardiac work was estimated as the product of mean arterial pressure and heart rate. Isolated arteries were studied to establish whether genetic alterations modified vascular reactivity. Despite higher levels of cardiac work in the Kv1.5(-/-) mice (versus WT mice at baseline and all doses of norepinephrine), myocardial blood flow was lower in Kv1.5(-/-) mice than in WT mice. At high levels of cardiac work, tissue oxygen tension dropped significantly along with ejection fraction. Expression of Kv1.5 channels in smooth muscle in the null background rescued this phenotype of impaired metabolic dilation. In isolated vessels from Kv1.5(-/-) mice, relaxation to H2O2 was impaired, but responses to adenosine and acetylcholine were normal compared with those from WT mice. CONCLUSIONS Kv1.5 channels in vascular smooth muscle play a critical role in coupling myocardial blood flow to cardiac metabolism. Absence of these channels disassociates metabolism from flow, resulting in cardiac pump dysfunction and tissue hypoxia.
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Affiliation(s)
| | - Liya Yin
- Department of Integrative Medical Sciences
| | - Raffi Bardakjian
- Departement Internal Medicine, Canton Medical Education Foundation
| | | | | | | | - John Kmetz
- Department of Integrative Medical Sciences
| | - Ian Bratz
- Department of Integrative Medical Sciences
| | | | - Masaki Nagane
- Department of Radiology and Medicine, Geisel School of Medicine at Dartmouth College
| | - Nadeem Khan
- Department of Radiology and Medicine, Geisel School of Medicine at Dartmouth College
| | - Huagang Hou
- Department of Radiology and Medicine, Geisel School of Medicine at Dartmouth College
| | - Periannan Kuppusamy
- Department of Radiology and Medicine, Geisel School of Medicine at Dartmouth College
| | | | | | | | - Moses O Oyewumi
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University
| | | | - Jonathan R Lindner
- Division of Cardiovascular Medicine, UHN62, Oregon Health and Science University
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24
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El-Yazbi AF, Abd-Elrahman KS, Moreno-Dominguez A. PKC-mediated cerebral vasoconstriction: Role of myosin light chain phosphorylation versus actin cytoskeleton reorganization. Biochem Pharmacol 2015; 95:263-78. [DOI: 10.1016/j.bcp.2015.04.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 04/16/2015] [Indexed: 10/23/2022]
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25
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Potassium channelopathy-like defect underlies early-stage cerebrovascular dysfunction in a genetic model of small vessel disease. Proc Natl Acad Sci U S A 2015; 112:E796-805. [PMID: 25646445 DOI: 10.1073/pnas.1420765112] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), caused by dominant mutations in the NOTCH3 receptor in vascular smooth muscle, is a genetic paradigm of small vessel disease (SVD) of the brain. Recent studies using transgenic (Tg)Notch3(R169C) mice, a genetic model of CADASIL, revealed functional defects in cerebral (pial) arteries on the surface of the brain at an early stage of disease progression. Here, using parenchymal arterioles (PAs) from within the brain, we determined the molecular mechanism underlying the early functional deficits associated with this Notch3 mutation. At physiological pressure (40 mmHg), smooth muscle membrane potential depolarization and constriction to pressure (myogenic tone) were blunted in PAs from TgNotch3(R169C) mice. This effect was associated with an ∼ 60% increase in the number of voltage-gated potassium (KV) channels, which oppose pressure-induced depolarization. Inhibition of KV1 channels with 4-aminopyridine (4-AP) or treatment with the epidermal growth factor receptor agonist heparin-binding EGF (HB-EGF), which promotes KV1 channel endocytosis, reduced KV current density and restored myogenic responses in PAs from TgNotch3(R169C) mice, whereas pharmacological inhibition of other major vasodilatory influences had no effect. KV1 currents and myogenic responses were similarly altered in pial arteries from TgNotch3(R169C) mice, but not in mesenteric arteries. Interestingly, HB-EGF had no effect on mesenteric arteries, suggesting a possible mechanistic basis for the exclusive cerebrovascular manifestation of CADASIL. Collectively, our results indicate that increasing the number of KV1 channels in cerebral smooth muscle produces a mutant vascular phenotype akin to a channelopathy in a genetic model of SVD.
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26
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Abd-Elrahman KS, Walsh MP, Cole WC. Abnormal Rho-associated kinase activity contributes to the dysfunctional myogenic response of cerebral arteries in type 2 diabetes. Can J Physiol Pharmacol 2015; 93:177-84. [PMID: 25660561 DOI: 10.1139/cjpp-2014-0437] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The structural and functional integrity of the brain, and therefore, cognition, are critically dependent on the appropriate control of blood flow within the cerebral circulation. Inadequate flow leads to ischemia, whereas excessive flow causes small vessel rupture and (or) blood-brain-barrier disruption. Cerebral blood flow is controlled through the interplay of several physiological mechanisms that regulate the contractile state of vascular smooth muscle cells (VSMCs) within the walls of cerebral resistance arteries and arterioles. The myogenic response of cerebral VSMCs is a key mechanism that is responsible for maintaining constant blood flow during variations in systemic pressure, i.e., flow autoregulation. Inappropriate myogenic control of cerebral blood flow is associated with, and prognostic of, neurological deterioration and poor outcome in patients with several conditions, including type 2 diabetes. Here, we review recent advances in our understanding of the role of inappropriate Rho-associated kinase activity as a cause of impaired myogenic regulation of cerebral arterial diameter in type 2 diabetes.
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Affiliation(s)
- Khaled S Abd-Elrahman
- The Smooth Muscle Research Group, Libin Cardiovascular Institute, Hotchkiss Brain Institute, and the Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada
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27
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Koide M, Wellman GC. SAH-induced MMP activation and K V current suppression is mediated via both ROS-dependent and ROS-independent mechanisms. ACTA NEUROCHIRURGICA. SUPPLEMENT 2015; 120:89-94. [PMID: 25366605 PMCID: PMC4465535 DOI: 10.1007/978-3-319-04981-6_15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Voltage-gated potassium (K V) channels regulate cerebral artery tone and have been implicated in subarachnoid hemorrhage (SAH)-induced pathologies. Here, we examined whether matrix metalloprotease (MMP) activation contributes to SAH-induced K V current suppression and cerebral artery constriction via activation of epidermal growth factor receptors (EGFRs). Using patch clamp electrophysiology, we observed that K V currents were selectively decreased in cerebral artery myocytes isolated from SAH model rabbits. Consistent with involvement of enhanced MMP and EGFR activity in SAH-induced K V current suppression, we found that: (1) oxyhemoglobin (OxyHb) and/or the exogenous EGFR ligand, heparin-binding EGF-like growth factor (HB-EGF), failed to induce further K V current suppression after SAH and (2) gelatin zymography detected significantly higher MMP-2 activity after SAH. The removal of reactive oxygen species (ROS) by combined treatment with superoxide dismutase (SOD) and catalase partially inhibited OxyHb-induced K V current suppression. However, these agents had little effect on OxyHb-induced MMP-2 activation. Interestingly, in the presence of a broad-spectrum MMP inhibitor (GM6001), OxyHb failed to cause K V current suppression. These data suggest that OxyHb suppresses K V currents through both ROS-dependent and ROS-independent pathways involving MMP activation. The ROS-independent pathway involves activation of MMP-2, whereas the ROS-dependent pathway involves activation of a second unidentified MMP or ADAM (a disintegrin and metalloprotease domain).
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Affiliation(s)
- Masayo Koide
- Department of Pharmacology, University of Vermont College of Medicine, 89 Beaumont Avenue, Burlington, VT, USA,
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28
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Cidad P, Miguel-Velado E, Ruiz-McDavitt C, Alonso E, Jiménez-Pérez L, Asuaje A, Carmona Y, García-Arribas D, López J, Marroquín Y, Fernández M, Roqué M, Pérez-García MT, López-López JR. Kv1.3 channels modulate human vascular smooth muscle cells proliferation independently of mTOR signaling pathway. Pflugers Arch 2014; 467:1711-22. [PMID: 25208915 DOI: 10.1007/s00424-014-1607-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 08/07/2014] [Accepted: 09/01/2014] [Indexed: 01/25/2023]
Abstract
Phenotypic modulation (PM) of vascular smooth muscle cells (VSMCs) is central to the process of intimal hyperplasia which constitutes a common pathological lesion in occlusive vascular diseases. Changes in the functional expression of Kv1.5 and Kv1.3 currents upon PM in mice VSMCs have been found to contribute to cell migration and proliferation. Using human VSMCs from vessels in which unwanted remodeling is a relevant clinical complication, we explored the contribution of the Kv1.5 to Kv1.3 switch to PM. Changes in the expression and the functional contribution of Kv1.3 and Kv1.5 channels were studied in contractile and proliferating VSMCs obtained from human donors. Both a Kv1.5 to Kv1.3 switch upon PM and an anti-proliferative effect of Kv1.3 blockers on PDGF-induced proliferation were observed in all vascular beds studied. When investigating the signaling pathways modulated by the blockade of Kv1.3 channels, we found that anti-proliferative effects of Kv1.3 blockers on human coronary artery VSMCs were occluded by selective inhibition of MEK/ERK and PLCγ signaling pathways, but were unaffected upon blockade of PI3K/mTOR pathway. The temporal course of the anti-proliferative effects of Kv1.3 blockers indicates that they have a role in the late signaling events essential for the mitogenic response to growth factors. These findings establish the involvement of Kv1.3 channels in the PM of human VSMCs. Moreover, as current therapies to prevent restenosis rely on mTOR blockers, our results provide the basis for the development of novel, more specific therapies.
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Affiliation(s)
- Pilar Cidad
- Departamento de Bioquímica y Biología Molecular y Fisiología e Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid y CSIC, Edificio IBGM, c/ Sanz y Forés s/n, 47003, Valladolid, Spain
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Chadha PS, Jepps TA, Carr G, Stott JB, Zhu HL, Cole WC, Greenwood IA. Contribution of kv7.4/kv7.5 heteromers to intrinsic and calcitonin gene-related peptide-induced cerebral reactivity. Arterioscler Thromb Vasc Biol 2014; 34:887-93. [PMID: 24558103 DOI: 10.1161/atvbaha.114.303405] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE Middle cerebral artery (MCA) diameter is regulated by inherent myogenic activity and the effect of potent vasodilators such as calcitonin gene-related peptide (CGRP). Previous studies showed that MCAs express KCNQ1, 4, and 5 potassium channel genes, and the expression products (Kv7 channels) participate in the myogenic control of MCA diameter. The present study investigated the contribution of Kv7.4 and Kv7.5 isoforms to myogenic and CGRP regulation of MCA diameter and determined whether they were affected in hypertensive animals. APPROACH AND RESULTS Isometric tension recordings performed on MCA from normotensive rats produced CGRP vasodilations that were inhibited by the pan-Kv7 channel blocker linopirdine (P<0.01) and after transfection of arteries with siRNA against KCNQ4 (P<0.01) but not KCNQ5. However, isobaric myography revealed that myogenic constriction in response to increases in intravascular pressure (20-80 mm Hg) was affected by both KCNQ4 and KCNQ5 siRNA. Proximity ligation assay signals were equally abundant for Kv7.4/Kv7.4 or Kv7.4/Kv7.5 antibody combinations but minimal for Kv7.5/Kv7.5 antibodies or Kv7.4/7.1 combinations. In contrast to systemic arteries, Kv7 function and Kv7.4 abundance in MCA were not altered in hypertensive rats. CONCLUSIONS This study reveals, for the first time to our knowledge, that in cerebral arteries, Kv7.4 and Kv7.5 proteins exist predominantly as a functional heterotetramer, which regulates intrinsic myogenicity and vasodilation attributed to CGRP. Surprisingly, unlike systemic arteries, Kv7 activity in MCAs is not affected by the development of hypertension, and CGRP-mediated vasodilation is well maintained. As such, cerebrovascular Kv7 channels could be amenable for therapeutic targeting in conditions such as cerebral vasospasm.
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Affiliation(s)
- Preet S Chadha
- From the Division of Biomedical Sciences, Pharmacology and Cell Physiology Research Group, St George's University of London, London, United Kingdom (P.S.C., T.A.J., G.C., J.B.S., I.A.G.); and The Smooth Muscle Research Group, Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada (H.-L.Z., W.C.C.)
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Baeyens N, Bouryi V, Morel N. Extracellular calcium modulates the inhibitory effect of 4-aminopyridine on Kv current in vascular smooth muscle cells. Eur J Pharmacol 2014; 723:116-23. [PMID: 24333216 DOI: 10.1016/j.ejphar.2013.11.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 10/30/2013] [Accepted: 11/15/2013] [Indexed: 11/30/2022]
Abstract
4-Aminopyridine is widely used as a Kv channel blocker. However, its mechanism of action is still a matter of debate. Extracellular calcium as well as 4-aminopyridine have been reported to interact with the activation kinetics of particular Kv channels. The objective of the present study was to investigate whether extracellular calcium could modulate the inhibition of Kv current by 4-aminopyridine in vascular myocytes. Kv current was recorded by using whole-cell patch-clamp in freshly isolated smooth muscle cells from rat mesenteric artery. Macroscopic properties of Kv current were not affected by change in extracellular calcium from 0 to 2mM. During a 10s depolarizing pulse, 4-aminopyridine inhibited the peak current without affecting the end-pulse current. The concentration-effect curve of 4-aminopyridine was shifted to the left in the presence of 2mM calcium compared to 0 calcium. After 4-aminopyridine washout, current recovery from block was slower in the presence than in the absence of calcium. Inhibition of Kv current by 4-aminopyridine (0.5mM) and the Kv2 blocker stromatoxin (50nM) was additive and stromatoxin did not alter the potentiation of 4-aminopyridine effect by extracellular calcium. These results showed that extracellular calcium modulated the inhibitory potency of 4-aminopyridine on Kv current in vascular myocytes. The component of Kv current that was inhibited by 4-aminopyridine in a calcium-sensitive manner was distinct from Kv2 current.
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Affiliation(s)
- Nicolas Baeyens
- Cell physiology, Institute of Neuroscience, Université catholique de Louvain, Bruxelles, Belgium
| | - Vitali Bouryi
- Cell physiology, Institute of Neuroscience, Université catholique de Louvain, Bruxelles, Belgium
| | - Nicole Morel
- Cell physiology, Institute of Neuroscience, Université catholique de Louvain, Bruxelles, Belgium.
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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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Role of genetic polymorphisms of ion channels in the pathophysiology of coronary microvascular dysfunction and ischemic heart disease. Basic Res Cardiol 2013; 108:387. [PMID: 24068186 PMCID: PMC3898136 DOI: 10.1007/s00395-013-0387-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/13/2013] [Accepted: 09/11/2013] [Indexed: 01/14/2023]
Abstract
Conventionally, ischemic heart disease (IHD) is equated with large vessel coronary disease. However, recent evidence has suggested a role of compromised microvascular regulation in the etiology of IHD. Because regulation of coronary blood flow likely involves activity of specific ion channels, and key factors involved in endothelium-dependent dilation, we proposed that genetic anomalies of ion channels or specific endothelial regulators may underlie coronary microvascular disease. We aimed to evaluate the clinical impact of single-nucleotide polymorphisms in genes encoding for ion channels expressed in the coronary vasculature and the possible correlation with IHD resulting from microvascular dysfunction. 242 consecutive patients who were candidates for coronary angiography were enrolled. A prospective, observational, single-center study was conducted, analyzing genetic polymorphisms relative to (1) NOS3 encoding for endothelial nitric oxide synthase (eNOS); (2) ATP2A2 encoding for the Ca2+/H+-ATPase pump (SERCA); (3) SCN5A encoding for the voltage-dependent Na+ channel (Nav1.5); (4) KCNJ8 and KCNJ11 encoding for the Kir6.1 and Kir6.2 subunits of K-ATP channels, respectively; and (5) KCN5A encoding for the voltage-gated K+ channel (Kv1.5). No significant associations between clinical IHD manifestations and polymorphisms for SERCA, Kir6.1, and Kv1.5 were observed (p > 0.05), whereas specific polymorphisms detected in eNOS, as well as in Kir6.2 and Nav1.5 were found to be correlated with IHD and microvascular dysfunction. Interestingly, genetic polymorphisms for ion channels seem to have an important clinical impact influencing the susceptibility for microvascular dysfunction and IHD, independent of the presence of classic cardiovascular risk factors.
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Abstract
The myogenic response has a critical role in regulation of blood flow to the brain. Increased intraluminal pressure elicits vasoconstriction, whereas decreased intraluminal pressure induces vasodilatation, thereby maintaining flow constant over the normal physiologic blood pressure range. Improved understanding of the molecular mechanisms underlying the myogenic response is crucial to identify deficiencies with pathologic consequences, such as cerebral vasospasm, hypertension, and stroke, and to identify potential therapeutic targets. Three mechanisms have been suggested to be involved in the myogenic response: (1) membrane depolarization, which induces Ca(2+) entry, activation of myosin light chain kinase, phosphorylation of the myosin regulatory light chains (LC(20)), increased actomyosin MgATPase activity, cross-bridge cycling, and vasoconstriction; (2) activation of the RhoA/Rho-associated kinase (ROCK) pathway, leading to inhibition of myosin light chain phosphatase by phosphorylation of MYPT1, the myosin targeting regulatory subunit of the phosphatase, and increased LC(20) phosphorylation; and (3) activation of the ROCK and protein kinase C pathways, leading to actin polymerization and the formation of enhanced connections between the actin cytoskeleton, plasma membrane, and extracellular matrix to augment force transmission. This review describes these three mechanisms, emphasizing recent developments regarding the importance of dynamic actin polymerization in the myogenic response of the cerebral vasculature.
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Fouillade C, Baron-Menguy C, Domenga-Denier V, Thibault C, Takamiya K, Huganir R, Joutel A. Transcriptome analysis for Notch3 target genes identifies Grip2 as a novel regulator of myogenic response in the cerebrovasculature. Arterioscler Thromb Vasc Biol 2012; 33:76-86. [PMID: 23117660 DOI: 10.1161/atvbaha.112.251736] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Notch3 is critically important for the structure and myogenic response of distal arteries, particularly of cerebral arteries. However, signaling pathways acting downstream of Notch3 remain largely unknown. METHODS AND RESULTS Transcriptome analysis using tail arteries of Notch3-null mice identified a core set of 17 novel Notch3-regulated genes confirmed in tail or brain arteries. Postnatal deletion of RBP-Jκ in smooth muscle cells recapitulated the structural, functional, and molecular defects of brain arteries induced by Notch3 deficiency. Transient in vivo blockade of the Notch pathway with γ-secretase inhibitors uncovered, in addition to Notch3, 6 immediate responders, including the voltage-gated potassium channel Kv1.5, which opposes to myogenic constriction of brain arteries, and the glutamate receptor-interacting protein 2 (Grip2) with no previously established role in the cerebrovasculature. We identified a vascular smooth muscle cell isoform of Grip2. We showed that Notch3-RBP-Jκ specifically regulates this isoform. Finally, we found that cerebral arteries of Grip2 mutant mice, which express an N-terminally truncated Grip2 protein, exhibited selective attenuation of pressure-induced contraction. CONCLUSIONS Our data provide insight into how Notch3 signals in the brain arteries, establishing the postnatal requirement of smooth muscle RBP-Jκ in this context. Notch3-regulated transcriptome provides potential for modulating myogenic response in the cerebrovasculature.
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Pathogenic role of store-operated and receptor-operated ca(2+) channels in pulmonary arterial hypertension. JOURNAL OF SIGNAL TRANSDUCTION 2012; 2012:951497. [PMID: 23056939 PMCID: PMC3465915 DOI: 10.1155/2012/951497] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/12/2012] [Accepted: 07/16/2012] [Indexed: 12/31/2022]
Abstract
Pulmonary circulation is an important circulatory system in which the body brings in oxygen. Pulmonary arterial hypertension (PAH) is a progressive and fatal disease that predominantly affects women. Sustained pulmonary vasoconstriction, excessive pulmonary vascular remodeling, in situ thrombosis, and increased pulmonary vascular stiffness are the major causes for the elevated pulmonary vascular resistance (PVR) in patients with PAH. The elevated PVR causes an increase in afterload in the right ventricle, leading to right ventricular hypertrophy, right heart failure, and eventually death. Understanding the pathogenic mechanisms of PAH is important for developing more effective therapeutic approach for the disease. An increase in cytosolic free Ca2+ concentration ([Ca2+]cyt) in pulmonary arterial smooth muscle cells (PASMC) is a major trigger for pulmonary vasoconstriction and an important stimulus for PASMC migration and proliferation which lead to pulmonary vascular wall thickening and remodeling. It is thus pertinent to define the pathogenic role of Ca2+ signaling in pulmonary vasoconstriction and PASMC proliferation to develop new therapies for PAH. [Ca2+]cyt in PASMC is increased by Ca2+ influx through Ca2+ channels in the plasma membrane and by Ca2+ release or mobilization from the intracellular stores, such as sarcoplasmic reticulum (SR) or endoplasmic reticulum (ER). There are two Ca2+ entry pathways, voltage-dependent Ca2+ influx through voltage-dependent Ca2+ channels (VDCC) and voltage-independent Ca2+ influx through store-operated Ca2+ channels (SOC) and receptor-operated Ca2+ channels (ROC). This paper will focus on the potential role of VDCC, SOC, and ROC in the development and progression of sustained pulmonary vasoconstriction and excessive pulmonary vascular remodeling in PAH.
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Ketsawatsomkron P, Lorca RA, Keen HL, Weatherford ET, Liu X, Pelham CJ, Grobe JL, Faraci FM, England SK, Sigmund CD. PPARγ regulates resistance vessel tone through a mechanism involving RGS5-mediated control of protein kinase C and BKCa channel activity. Circ Res 2012; 111:1446-58. [PMID: 22962432 DOI: 10.1161/circresaha.112.271577] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Activation of peroxisome proliferator-activated receptor-γ (PPARγ) by thiazolidinediones lowers blood pressure, whereas PPARγ mutations cause hypertension. Previous studies suggest these effects may be mediated through the vasculature, but the underlying mechanisms remain unclear. OBJECTIVE To identify PPARγ mechanisms and transcriptional targets in vascular smooth muscle and their role in regulating resistance artery tone. METHODS AND RESULTS We studied mesenteric artery (MA) from transgenic mice expressing dominant-negative (DN) mutant PPARγ driven by a smooth muscle cell-specific promoter. MA from transgenic mice exhibited a robust increase in myogenic tone. Patch clamp analysis revealed a reduced large conductance Ca(2+)-activated K(+) (BKCa) current in freshly dissociated smooth muscle cell from transgenic MA. Inhibition of protein kinase C corrected both enhanced myogenic constriction and impaired the large conductance Ca(2+)-activated K(+) channel function. Gene expression profiling revealed a marked loss of the regulator of G protein signaling 5 (RGS5) mRNA in transgenic MA, which was accompanied by a substantial increase in angiotensin II-induced constriction in MA. Small interfering RNA targeting RGS5 caused augmented myogenic tone in intact mesenteric arteries and increased activation of protein kinase C in smooth muscle cell cultures. PPARγ and PPARδ each bind to a PPAR response element close to the RGS5 promoter. RGS5 expression in nontransgenic MA was induced after activation of either PPARγ or PPARδ, an effect that was markedly blunted by DN PPARγ. CONCLUSIONS We conclude that RGS5 in smooth muscle is a PPARγ and PPARδ target, which when activated blunts angiotensin II-mediated activation of protein kinase C, and preserves the large conductance Ca(2+)-activated K(+) channel activity, thus providing tight control of myogenic tone in the microcirculation.
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Affiliation(s)
- Pimonrat Ketsawatsomkron
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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Greenwood IA. Intricate vascular architecture revealed after removing the scaffolding: PSD95 crucial for vascular Kv1 function. J Physiol 2012; 589:5901. [PMID: 22174134 DOI: 10.1113/jphysiol.2011.220202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Affiliation(s)
- Iain A Greenwood
- Pharmacology & Cell Physiology Research group, Division of Biomedical Sciences, St George's, University of London, London, UK.
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Bielanska J, Hernández-Losa J, Moline T, Somoza R, Ramón Y Cajal S, Condom E, Ferreres JC, Felipe A. Increased voltage-dependent K + channel Kv1.3 and Kv1.5 expression correlates with leiomyosarcoma aggressiveness. Oncol Lett 2012; 4:227-230. [PMID: 22844358 DOI: 10.3892/ol.2012.718] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 05/04/2012] [Indexed: 01/07/2023] Open
Abstract
Voltage-dependent K+ channels (Kv) are involved in the proliferation and differentiation of mammalian cells, since Kv antagonists impair cell cycle progression. Although myofibers are terminally differentiated, some myoblasts may re-enter the cell cycle and proliferate. Since Kv1.3 and Kv1.5 expression is remodeled during tumorigenesis and is involved in smooth muscle proliferation, the purpose of this study was to analyze the expression of Kv1.3 and Kv1.5 in smooth muscle neoplasms. In the present study, we examined human samples of smooth muscle tumors together with healthy specimens. Thus, leiomyoma (LM) and leiomyosarcoma (LMS) tumors were analyzed. Results showed that Kv1.3 was poorly expressed in the healthy muscle and indolent LM specimens, whereas aggressive LMS showed high levels of Kv1.3 expression. Kv1.5 staining was correlated with malignancy. The findings show a remodeling of Kv1.3 and Kv1.5 in human smooth muscle sarcoma. A correlation of Kv1.3 and Kv1.5 expression with tumor aggressiveness was observed. Thus, our results indicate Kv1.5 and Kv1.3 as potential tumorigenic targets for aggressive human LMS.
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Affiliation(s)
- Joanna Bielanska
- Molecular Physiology Laboratory, Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University of Barcelona, E-08028 Barcelona
| | - Javier Hernández-Losa
- Department of Pathology, Vall d'Hebron University Hospital, Autonomous University of Barcelona, E-08035 Barcelona
| | - Teresa Moline
- Department of Pathology, Vall d'Hebron University Hospital, Autonomous University of Barcelona, E-08035 Barcelona
| | - Rosa Somoza
- Department of Pathology, Vall d'Hebron University Hospital, Autonomous University of Barcelona, E-08035 Barcelona
| | - Santiago Ramón Y Cajal
- Department of Pathology, Vall d'Hebron University Hospital, Autonomous University of Barcelona, E-08035 Barcelona
| | - Enric Condom
- Department of Pathology and Experimental Therapeutics, Bellvitge University Hospital-IDIBELL, L'Hospitalet de Llobregat, E-08907 Barcelona, Spain
| | - Joan Carles Ferreres
- Department of Pathology, Vall d'Hebron University Hospital, Autonomous University of Barcelona, E-08035 Barcelona
| | - Antonio Felipe
- Molecular Physiology Laboratory, Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University of Barcelona, E-08028 Barcelona
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Asano S, Bratz IN, Berwick ZC, Fancher IS, Tune JD, Dick GM. Penitrem A as a tool for understanding the role of large conductance Ca(2+)/voltage-sensitive K(+) channels in vascular function. J Pharmacol Exp Ther 2012; 342:453-60. [PMID: 22580348 DOI: 10.1124/jpet.111.191072] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Large conductance, Ca(2+)/voltage-sensitive K(+) channels (BK channels) are well characterized, but their physiological roles, often determined through pharmacological manipulation, are less clear. Iberiotoxin is considered the "gold standard" antagonist, but cost and membrane-impermeability limit its usefulness. Economical and membrane-permeable alternatives could facilitate the study of BK channels. Thus, we characterized the effect of penitrem A, a tremorigenic mycotoxin, on BK channels and demonstrate its utility for studying vascular function in vitro and in vivo. Whole-cell currents from human embryonic kidney 293 cells transfected with hSlo α or α + β1 were blocked >95% by penitrem A (IC(50) 6.4 versus 64.4 nM; p < 0.05). Furthermore, penitrem A inhibited BK channels in inside-out and cell-attached patches, whereas iberiotoxin could not. Inhibitory effects of penitrem A on whole-cell K(+) currents were equivalent to iberiotoxin in canine coronary smooth muscle cells. As for specificity, penitrem A had no effect on native delayed rectifier K(+) currents, cloned voltage-dependent Kv1.5 channels, or native ATP-dependent K(ATP) current. Penitrem A enhanced the sensitivity to K(+)-induced contraction in canine coronary arteries by 23 ± 5% (p < 0.05) and increased the blood pressure response to phenylephrine in anesthetized mice by 36 ± 11% (p < 0.05). Our data indicate that penitrem A is a useful tool for studying the role of BK channels in vascular function and is practical for cell and tissue (in vitro) studies as well as anesthetized animal (in vivo) experiments.
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Affiliation(s)
- Shinichi Asano
- Division of Exercise Physiology, Center for Cardiovascular and Respiratory Sciences, West Virginia University School of Medicine, Morgantown, West Virginia 26506, USA
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40
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Kuhr FK, Smith KA, Song MY, Levitan I, Yuan JXJ. New mechanisms of pulmonary arterial hypertension: role of Ca²⁺ signaling. Am J Physiol Heart Circ Physiol 2012; 302:H1546-62. [PMID: 22245772 DOI: 10.1152/ajpheart.00944.2011] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Pulmonary arterial hypertension (PAH) is a severe and progressive disease that usually culminates in right heart failure and death if left untreated. Although there have been substantial improvements in our understanding and significant advances in the management of this disease, there is a grim prognosis for patients in the advanced stages of PAH. A major cause of PAH is increased pulmonary vascular resistance, which results from sustained vasoconstriction, excessive pulmonary vascular remodeling, in situ thrombosis, and increased pulmonary vascular stiffness. In addition to other signal transduction pathways, Ca(2+) signaling in pulmonary artery smooth muscle cells (PASMCs) plays a central role in the development and progression of PAH because of its involvement in both vasoconstriction, through its pivotal effect of PASMC contraction, and vascular remodeling, through its stimulatory effect on PASMC proliferation. Altered expression, function, and regulation of ion channels and transporters in PASMCs contribute to an increased cytosolic Ca(2+) concentration and enhanced Ca(2+) signaling in patients with PAH. This review will focus on the potential pathogenic role of Ca(2+) mobilization, regulation, and signaling in the development and progression of PAH.
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Affiliation(s)
- Frank K Kuhr
- Section of Pulmonary, Critical Care, Sleep, and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA
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41
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Chadha PS, Greenwood IA, Zhong XZ, Cole WC. Letter to the Editor re Mani et al. Br J Pharmacol 2011; 164:250-1; author reply 252-3. [DOI: 10.1111/j.1476-5381.2011.01454.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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42
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Role of myosin light chain kinase and myosin light chain phosphatase in the resistance arterial myogenic response to intravascular pressure. Arch Biochem Biophys 2011; 510:160-73. [DOI: 10.1016/j.abb.2011.02.024] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/24/2011] [Accepted: 02/28/2011] [Indexed: 12/19/2022]
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44
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Cheong A, Li J, Sukumar P, Kumar B, Zeng F, Riches K, Munsch C, Wood IC, Porter KE, Beech DJ. Potent suppression of vascular smooth muscle cell migration and human neointimal hyperplasia by KV1.3 channel blockers. Cardiovasc Res 2010; 89:282-9. [PMID: 20884640 PMCID: PMC3020133 DOI: 10.1093/cvr/cvq305] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIM The aim of the study was to determine the potential for K(V)1 potassium channel blockers as inhibitors of human neoinitimal hyperplasia. METHODS AND RESULTS Blood vessels were obtained from patients or mice and studied in culture. Reverse transcriptase-polymerase chain reaction and immunocytochemistry were used to detect gene expression. Whole-cell patch-clamp, intracellular calcium measurement, cell migration assays, and organ culture were used to assess channel function. K(V)1.3 was unique among the K(V)1 channels in showing preserved and up-regulated expression when the vascular smooth muscle cells switched to the proliferating phenotype. There was strong expression in neointimal formations. Voltage-dependent potassium current in proliferating cells was sensitive to three different blockers of K(V)1.3 channels. Calcium entry was also inhibited. All three blockers reduced vascular smooth muscle cell migration and the effects were non-additive. One of the blockers (margatoxin) was highly potent, suppressing cell migration with an IC(50) of 85 pM. Two of the blockers were tested in organ-cultured human vein samples and both inhibited neointimal hyperplasia. CONCLUSION K(V)1.3 potassium channels are functional in proliferating mouse and human vascular smooth muscle cells and have positive effects on cell migration. Blockers of the channels may be useful as inhibitors of neointimal hyperplasia and other unwanted vascular remodelling events.
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Affiliation(s)
- Alex Cheong
- Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds LS2 9JT, UK
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45
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Zhong XZ, Abd-Elrahman KS, Liao CH, El-Yazbi AF, Walsh EJ, Walsh MP, Cole WC. Stromatoxin-sensitive, heteromultimeric Kv2.1/Kv9.3 channels contribute to myogenic control of cerebral arterial diameter. J Physiol 2010; 588:4519-37. [PMID: 20876197 DOI: 10.1113/jphysiol.2010.196618] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cerebral vascular smooth muscle contractility plays a crucial role in controlling arterial diameter and, thereby, blood flow regulation in the brain. A number of K(+) channels have been suggested to contribute to the regulation of diameter by controlling smooth muscle membrane potential (E(m)) and Ca(2+) influx. Previous studies indicate that stromatoxin (ScTx1)-sensitive, Kv2-containing channels contribute to the control of cerebral arterial diameter at 80 mmHg, but their precise role and molecular composition were not determined. Here, we tested if Kv2 subunits associate with 'silent' subunits from the Kv5, Kv6, Kv8 or Kv9 subfamilies to form heterotetrameric channels that contribute to control of diameter of rat middle cerebral arteries (RMCAs) over a range of intraluminal pressure from 10 to 100 mmHg. The predominant mRNAs expressed by RMCAs encode Kv2.1 and Kv9.3 subunits. Co-localization of Kv2.1 and Kv9.3 proteins at the plasma membrane of dissociated single RMCA myocytes was detected by proximity ligation assay. ScTx1-sensitive native current of RMCA myocytes and Kv2.1/Kv9.3 currents exhibited functional identity based on the similarity of their deactivation kinetics and voltage dependence of activation that were distinct from those of homomultimeric Kv2.1 channels. ScTx1 treatment enhanced the myogenic response of pressurized RMCAs between 40 and 100 mmHg, but this toxin also caused constriction between 10 and 40 mmHg that was not previously observed following inhibition of large conductance Ca(2+)-activated K(+) (BK(Ca)) and Kv1 channels. Taken together, this study defines the molecular basis of Kv2-containing channels and contributes to our understanding of the functional significance of their expression in cerebral vasculature. Specifically, our findings provide the first evidence of heteromultimeric Kv2.1/Kv9.3 channel expression in RMCA myocytes and their distinct contribution to control of cerebral arterial diameter over a wider range of E(m) and transmural pressure than Kv1 or BK(Ca) channels owing to their negative range of voltage-dependent activation.
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Affiliation(s)
- Xi Zoë Zhong
- The Smooth Muscle Research Group, Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, 3330 Hospital Drive N.W., Calgary, Alberta, Canada T2N 4N1
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Zhong XZ, Harhun MI, Olesen SP, Ohya S, Moffatt JD, Cole WC, Greenwood IA. Participation of KCNQ (Kv7) potassium channels in myogenic control of cerebral arterial diameter. J Physiol 2010; 588:3277-93. [PMID: 20624791 PMCID: PMC2976022 DOI: 10.1113/jphysiol.2010.192823] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 07/09/2010] [Indexed: 01/11/2023] Open
Abstract
KCNQ gene expression was previously shown in various rodent blood vessels, where the products of KCNQ4 and KCNQ5, Kv7.4 and Kv7.5 potassium channel subunits, respectively, have an influence on vascular reactivity. The aim of this study was to determine if small cerebral resistance arteries of the rat express KCNQ genes and whether Kv7 channels participate in the regulation of myogenic control of diameter. Quantitative reverse transcription polymerase chain reaction (QPCR) was undertaken using RNA isolated from rat middle cerebral arteries (RMCAs) and immunocytochemistry was performed using Kv7 subunit-specific antibodies and freshly isolated RMCA myocytes. KCNQ4 message was more abundant than KCNQ5 = KCNQ1, but KCNQ2 and KCNQ3 message levels were negligible. Kv7.1, Kv7.4 and Kv7.5 immunoreactivity was present at the sarcolemma of freshly isolated RMCA myocytes. Linopirdine (1 microm) partially depressed, whereas the Kv7 activator S-1 (3 and/or 20 microm) enhanced whole-cell Kv7.4 (in HEK 293 cells), as well as native RMCA myocyte Kv current amplitude. The effects of S-1 were voltage-dependent, with progressive loss of stimulation at potentials of >15 mV. At the concentrations employed linopirdine and S-1 did not alter currents due to recombinant Kv1.2/Kv1.5 or Kv2.1/Kv9.3 channels (in HEK 293 cells) that are also expressed by RMCA myocytes. In contrast, another widely used Kv7 blocker, XE991 (10 microm), significantly attenuated native Kv current and also reduced Kv1.2/Kv1.5 and Kv2.1/Kv9.3 currents. Pressurized arterial myography was performed using RMCAs exposed to intravascular pressures of 10-100 mmHg. Linopirdine (1 microm) enhanced the myogenic response at 20 mmHg, whereas the activation of Kv7 channels with S-1 (20 microm) inhibited myogenic constriction at >20 mmHg and reversed the increased myogenic response produced by suppression of Kv2-containing channels with 30 nm stromatoxin (ScTx1). These data reveal a novel contribution of KCNQ gene products to the regulation of myogenic control of cerebral arterial diameter and suggest that Kv7 channel activating drugs may be appropriate candidates for the development of an effective therapy to ameliorate cerebral vasospasm.
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Affiliation(s)
- Xi Zoë Zhong
- Ion Channels and Cell Signaling Centre, Division of Basic Medical Sciences, St George's University of London, London SW17 0RE, UK
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47
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El-Yazbi AF, Johnson RP, Walsh EJ, Takeya K, Walsh MP, Cole WC. Pressure-dependent contribution of Rho kinase-mediated calcium sensitization in serotonin-evoked vasoconstriction of rat cerebral arteries. J Physiol 2010; 588:1747-62. [PMID: 20351047 DOI: 10.1113/jphysiol.2010.187146] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Our understanding of the cellular signalling mechanisms contributing to agonist-induced constriction is almost exclusively based on the study of conduit arteries. Resistance arteries/arterioles have received less attention as standard biochemical approaches lack the necessary sensitivity to permit quantification of phosphoprotein levels in these small vessels. Here, we have employed a novel, highly sensitive Western blotting method to assess: (1) the contribution of Ca(2+) sensitization mediated by phosphorylation of myosin light chain phosphatase targeting subunit 1 (MYPT1) and the 17 kDa PKC-potentiated protein phosphatase 1 inhibitor protein (CPI-17) to serotonin (5-HT)-induced constriction of rat middle cerebral arteries, and (2) whether there is any interplay between pressure-induced myogenic and agonist-induced mechanisms of vasoconstriction. Arterial diameter and levels of MYPT1 (T697 and T855), CPI-17 and 20 kDa myosin light chain subunit (LC(20)) phosphorylation were determined following treatment with 5-HT (1 micromol l(1)) at 10 or 60 mmHg in the absence and presence of H1152 or GF109203X to suppress the activity of Rho-associated kinase (ROK) and protein kinase C (PKC), respectively. Although H1152 and GF109203X suppressed 5-HT-induced constriction and reduced phospho-LC(20) content at 10 mmHg, we failed to detect any increase in MYPT1 or CPI-17 phosphorylation. In contrast, an increase in MYPT1-T697 and MYPT1-T855 phosphorylation, but not phospho-CPI-17 content, was apparent at 60 mmHg following exposure to 5-HT, and the phosphorylation of both MYPT1 sites was sensitive to H1152 inhibition of ROK. The involvement of MYPT1 phosphorylation in the response to 5-HT at 60 mmHg was not dependent on force generation per se, as inhibition of cross-bridge cycling with blebbistatin (10 micromol l(1)) did not affect phosphoprotein content. Taken together, the data indicate that Ca(2+) sensitization owing to ROK-mediated phosphorylation of MYPT1 contributes to 5-HT-evoked vasoconstriction only in the presence of pressure-induced myogenic activation. These findings provide novel evidence of an interplay between myogenic- and agonist-induced vasoconstriction in cerebral resistance arteries.
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Affiliation(s)
- Ahmed F El-Yazbi
- The Smooth Muscle Research Group, Department of Physiology and Pharmacology, Faculty of Medicine, University of Calgary, 3330 Hospital Drive N.W., Calgary, Alberta, Canada T2N 4N1
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Abstract
Neuronal activity is communicated to the cerebral vasculature so that adequate perfusion of brain tissue is maintained at all levels of neuronal metabolism. An increase in neuronal activity is accompanied by vasodilation and an increase in local cerebral blood flow. This process, known as neurovascular coupling (NVC) or functional hyperemia, is essential for cerebral homeostasis and survival. Neuronal activity is encoded in astrocytic Ca(2+) signals that travel to astrocytic processes (;endfeet') encasing parenchymal arterioles within the brain. Astrocytic Ca(2+) signals cause the release of vasoactive substances to cause relaxation, and in some circumstances contraction, of the smooth muscle cells (SMCs) of parenchymal arterioles to modulate local cerebral blood flow. Activation of potassium channels in the SMCs has been proposed to mediate NVC. Here, the current state of knowledge of NVC and potassium channels in parenchymal arterioles is reviewed.
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Affiliation(s)
- Kathryn M Dunn
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, VT 05405, USA
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Manoury B, Etheridge SL, Reid J, Gurney AM. Organ culture mimics the effects of hypoxia on membrane potential, K(+) channels and vessel tone in pulmonary artery. Br J Pharmacol 2009; 158:848-61. [PMID: 19694728 DOI: 10.1111/j.1476-5381.2009.00353.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND AND PURPOSE Blood vessel culture is gaining interest for use with transfection-based techniques, but alters the contractile properties of the vessels. The present study tested the effects of culture on the intrinsic tone of rat pulmonary arteries (PAs) and examined the function and expression of K(+) channels regulating the resting membrane potential (E(m)) and tone of pulmonary artery smooth muscle cells (PASMCs). EXPERIMENTAL APPROACH Rat intrapulmonary arteries were isolated and cultured under standard and modified conditions. Contractile responses of fresh and cultured PA were compared using vessel myograph. Electrophysiology experiments on isolated PASMCs used the patch-clamp technique. K(+) channel expression was quantified using reverse transcription and real-time PCR. KEY RESULTS After 4 days in culture vessels contracted to phenylephrine, but relaxation to carbachol was significantly impaired. Contractile responses to 10 mM KCl, 4-aminopyridine and tetraethylammonium increased, and vessels developed an uncharacteristic relaxation response to Ca(2+)-free solution, nifedipine and levcromakalim. PASMCs from cultured vessels were depolarized and K(+) currents reduced, in association with down-regulation of K(v)1.5, K(v)2.1 and TWIK-related acid-sensitive K(+) channel-1 mRNA. These changes were partially reversed by increased oxygenation of the culture medium or removing the endothelium before culture. CONCLUSIONS AND IMPLICATIONS Culture of PA for 3-4 days induced loss of functional K(+) channels, depolarization of PASMCs, Ca(2+) influx, intrinsic tone and spontaneous constrictions, similar to the effects of chronic hypoxia. This limits the use of cultured vessels for studying excitation-contraction coupling, although oxygenating the culture medium and removing the endothelium can help to retain normal smooth muscle function.
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Straub SV, Girouard H, Doetsch PE, Hannah RM, Wilkerson MK, Nelson MT. Regulation of intracerebral arteriolar tone by K(v) channels: effects of glucose and PKC. Am J Physiol Cell Physiol 2009; 297:C788-96. [PMID: 19605735 DOI: 10.1152/ajpcell.00148.2009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Voltage-gated potassium (K(v)) channels in vascular smooth muscle cells (VSMC) are critical regulators of membrane potential and vascular tone. These channels exert a hyperpolarizing influence to counteract the depolarizing effects of intraluminal pressure and vasoconstrictors. However, the contribution of K(v) channel activity to the functional regulation of cerebral (parenchymal) arterioles within the brain is not known. Thus K(v) channel properties in parenchymal arteriolar SMCs were characterized. Isolated, pressurized parenchymal arterioles and arterioles in cortical brain slices exhibited robust constriction in the presence of the K(v) channel inhibitor 4-aminopyridine (4-AP). 4-AP also decreased the amplitude of K(v) currents recorded from SMCs. The steady-state activation and inactivation properties of K(v) currents suggested that these channels are composed of K(v)1.2 and 1.5 subunits, which was confirmed by RT-PCR. K(v) channels can be regulated by extracellular glucose, which may be involved in the functional hyperemic response in the brain. Thus the effects of glucose on K(v) channel activity and arteriolar function were investigated. Elevation of glucose from 4 to 14 mM significantly decreased the peak K(v) current amplitude and constricted arterioles. Arteriolar constriction was prevented by inhibition of protein kinase C (PKC), consistent with previous studies showing enhanced PKC activity in the presence of elevated glucose. In cortical brain slices, the dilation generated by neuronal activity induced by electrical field stimulation was decreased by 54% in 14 mM glucose when compared with the dilation in 4 mM glucose. In anesthetized mice the whisker stimulation-induced increase in local cerebral blood flow was also significantly decreased in 14 mM glucose, and this effect was similarly prevented by PKC inhibition. These findings point to a critical role for K(v) channels in the regulation of intracerebral arteriolar function and suggest that changes in perivascular glucose levels could directly alter vascular diameter resulting in a modulation of local cerebral blood flow.
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Affiliation(s)
- Stephen V Straub
- Dept. of Pharmacology, University of Vermont, Burlington, VT 05405, USA
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