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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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Han S, Zhuang D, Wang J, Ju C. Inhibition of neuronal Kv7 channels ameliorates MK-801-induced cognitive dysfunction in mice via up-regulating NAMPT expression. Neurosci Lett 2023; 814:137471. [PMID: 37673371 DOI: 10.1016/j.neulet.2023.137471] [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: 04/27/2023] [Revised: 07/01/2023] [Accepted: 09/04/2023] [Indexed: 09/08/2023]
Abstract
PURPOSE Abnormal energy metabolism affects cognitive function in schizophrenia. Nicotinamide phosphoribosyltransferase (NAMPT), as the rate-limiting enzyme of nicotinamide adenine dinucleotide (NAD+), is involved in energy metabolism by regulating the synthesis of NAD+. This study aims to clarify whether inhibition of Kv7 channels improves cognitive impairment by up-regulating NAMPT expression to increase the level of NAD+. METHODS The dominant negative pore mutation of KCNQ2 in transgenic mice was achieved by mutating residual 279-Gly to Ser (rQ2-G279S). A cognitive deficit model was established by injecting MK-801 into C57BL/6J mice. Y-maze and prepulse inhibition (PPI) tests were performed to evaluate cognitive ability. Gene and protein expression of NAMPT in the mouse hippocampus, cortex, and PC-12 cells were measured by qRT-PCR and Western blot. The level of NAD+ was measured by a WST-8 assay. RESULTS The Y-maze and PPI results showed that genetic or pharmacological inhibition of Kv7 channels by XE991 enhanced cognitive function in mice. Furthermore, inhibition of Kv7 channels increased the gene and protein expression of NAMPT and the level of NAD+ in the hippocampus and cortex of the above animal model. Similarly, XE991 treatment increased NAMPT expression and NAD+ levels in PC-12 cells. NAMPT inhibitor FK866 and Kv7 channel opener retigabine reversed the effects of XE991 in vivo and in vitro. In addition, XE991 increased pAMPK protein expression in PC-12 cells, while AMPK inhibitor Compound C counteracted the effect of XE991 on increasing NAMPT expression and NAD+ levels. CONCLUSIONS Suppression of Kv7 channel function improved spatial working memory and PPI impairment. This result may be achieved by activating AMPK to up-regulate NAMPT expression and thus increase NAD+ levels.
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Affiliation(s)
- Shuo Han
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, China
| | - Dongpei Zhuang
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, China
| | - Jing Wang
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, China; Translational Pharmaceutical Laboratory, Jining First People's Hospital, Shandong First Medical University, Jining 272000, China
| | - Chuanxia Ju
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, China.
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3
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Potassium channelopathies associated with epilepsy-related syndromes and directions for therapeutic intervention. Biochem Pharmacol 2023; 208:115413. [PMID: 36646291 DOI: 10.1016/j.bcp.2023.115413] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
A number of mutations to members of several CNS potassium (K) channel families have been identified which result in rare forms of neonatal onset epilepsy, or syndromes of which one prominent characteristic is a form of epilepsy. Benign Familial Neonatal Convulsions or Seizures (BFNC or BFNS), also referred to as Self-Limited Familial Neonatal Epilepsy (SeLNE), results from mutations in 2 members of the KV7 family (KCNQ) of K channels; while generally self-resolving by about 15 weeks of age, these mutations significantly increase the probability of generalized seizure disorders in the adult, in some cases they result in more severe developmental syndromes. Epilepsy of Infancy with Migrating Focal Seizures (EIMSF), or Migrating Partial Seizures of Infancy (MMPSI), is a rare severe form of epilepsy linked primarily to gain of function mutations in a member of the sodium-dependent K channel family, KCNT1 or SLACK. Finally, KCNMA1 channelopathies, including Liang-Wang syndrome (LIWAS), are rare combinations of neurological symptoms including seizure, movement abnormalities, delayed development and intellectual disabilities, with Liang-Wang syndrome an extremely serious polymalformative syndrome with a number of neurological sequelae including epilepsy. These are caused by mutations in the pore-forming subunit of the large-conductance calcium-activated K channel (BK channel) KCNMA1. The identification of these rare but significant channelopathies has resulted in a resurgence of interest in their treatment by direct pharmacological or genetic modulation. We will briefly review the genetics, biophysics and pharmacology of these K channels, their linkage with the 3 syndromes described above, and efforts to more effectively target these syndromes.
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4
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Emerging mechanisms involving brain Kv7 channel in the pathogenesis of hypertension. Biochem Pharmacol 2022; 206:115318. [PMID: 36283445 DOI: 10.1016/j.bcp.2022.115318] [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: 08/24/2022] [Revised: 10/15/2022] [Accepted: 10/17/2022] [Indexed: 12/14/2022]
Abstract
Hypertension is a prevalent health problem inducing many organ damages. The pathogenesis of hypertension involves a complex integration of different organ systems including the brain. The elevated sympathetic nerve activity is closely related to the etiology of hypertension. Ion channels are critical regulators of neuronal excitability. Several mechanisms have been proposed to contribute to hypothalamic-driven elevated sympathetic activity, including altered ion channel function. Recent findings indicate one of the voltage-gated potassium channels, Kv7 channels (M channels), plays a vital role in regulating cardiovascular-related neurons activity, and the expression of Kv7 channels is downregulated in hypertension. This review highlights recent findings that the Kv7 channels in the brain, blood vessels, and kidneys are emerging targets involved in the pathogenesis of hypertension, suggesting new therapeutic targets for treating drug-resistant, neurogenic hypertension.
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5
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Peixoto-Neves D, Kanthakumar P, Afolabi JM, Soni H, Buddington RK, Adebiyi A. K V7.1 channel blockade inhibits neonatal renal autoregulation triggered by a step decrease in arterial pressure. Am J Physiol Renal Physiol 2022; 322:F197-F207. [PMID: 35001664 PMCID: PMC8816635 DOI: 10.1152/ajprenal.00568.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
KV7 channels, the voltage-gated K+ channels encoded by KCNQ genes, mediate heterogeneous vascular responses in rodents. Postnatal changes in the functional expression of KV7 channels have been reported in rodent saphenous arteries, but their physiological function in the neonatal renal vascular bed is unclear. Here, we report that, unlike adult pigs, only KCNQ1 (KV7.1) out of the five members of KCNQ genes was detected in neonatal pig renal microvessels. KCNQ1 is present in fetal pig kidneys as early as day 50 of gestation, and the level of expression remains the same up to postnatal day 21. Activation of renal vascular smooth muscle cell (SMC) KV7.1 stimulated whole cell currents, inhibited by HMR1556 (HMR), a selective KV7.1 blocker. HMR did not change the steady-state diameter of isolated renal microvessels. Similarly, intrarenal artery infusion of HMR did not alter mean arterial pressure, renal blood flow, and renal vascular resistance in the pigs. An ∼20 mmHg reduction in mean arterial pressure evoked effective autoregulation of renal blood flow, which HMR inhibited. We conclude that 1) the expression of KCNQ isoforms in porcine renal microvessels is dependent on kidney maturation, 2) KV7.1 is functionally expressed in neonatal pig renal vascular SMCs, 3) a decrease in arterial pressure up to 20 mmHg induces renal autoregulation in neonatal pigs, and 4) SMC KV7.1 does not control basal renal vascular tone but contributes to neonatal renal autoregulation triggered by a step decrease in arterial pressure.NEW & NOTEWORTHY KV7.1 is present in fetal pig kidneys as early as day 50 of gestation, and the level of expression remains the same up to postnatal day 21. KV7.1 is functionally expressed in neonatal pig renal vascular smooth muscle cells (SMCs). A decrease in arterial pressure up to 20 mmHg induces renal autoregulation in neonatal pigs. Although SMC KV7.1 does not control basal renal vascular resistance, its inhibition blunts neonatal renal autoregulation engendered by a step decrease in arterial pressure.
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Affiliation(s)
- Dieniffer Peixoto-Neves
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | | | - Jeremiah M. Afolabi
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Hitesh Soni
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
| | | | - Adebowale Adebiyi
- 1Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee
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6
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Rezola M, Castellanos A, Gasull X, Comes N. Functional Interaction Between Caveolin 1 and LRRC8-Mediated Volume-Regulated Anion Channel. Front Physiol 2021; 12:691045. [PMID: 34658903 PMCID: PMC8517123 DOI: 10.3389/fphys.2021.691045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 09/06/2021] [Indexed: 11/13/2022] Open
Abstract
Volume-regulated anion channel (VRAC), constituted by leucine-rich repeat-containing 8 (LRRC8) heteromers, is crucial for volume homeostasis in vertebrate cells. This widely expressed channel has been associated with membrane potential modulation, proliferation, migration, apoptosis, and glutamate release. VRAC is activated by cell swelling and by low cytoplasmic ionic strength or intracellular guanosine 5′-O-(3-thiotriphosphate) (GTP-γS) in isotonic conditions. Despite the substantial number of studies that characterized the biophysical properties of VRAC, its mechanism of activation remains a mystery. Different evidence suggests a possible effect of caveolins in modulating VRAC activity: (1) Caveolin 1 (Cav1)-deficient cells display insignificant swelling-induced Cl– currents mediated by VRAC, which can be restored by Cav1 expression; (2) Caveolin 3 (Cav3) knockout mice display reduced VRAC currents; and (3) Interaction between LRRC8A, the essential subunit for VRAC, and Cav3 has been found in transfected human embryonic kidney 293 (HEK 293) cells. In this study, we demonstrate a physical interaction between endogenous LRRC8A and Cav1 proteins, that is enhanced by hypotonic stimulation, suggesting that this will increase the availability of the channel to Cav1. In addition, LRRC8A targets plasma membrane regions outside caveolae of HEK 293 cells where it associates with non-caveolar Cav1. We propose that a rise in cell membrane tension by hypotonicity would flatten caveolae, as described previously, increasing the amount of Cav1 outside of caveolar structures interacting with VRAC. Besides, the expression of Cav1 in HEK Cav1- cells increases VRAC current density without changing the main biophysical properties of the channel. The present study provides further evidence on the relevance of Cav1 on the activation of endothelial VRAC through a functional molecular interaction.
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Affiliation(s)
- Mikel Rezola
- Neurophysiology Laboratory, Physiology Unit, Department of Biomedicine, Medical School, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Aida Castellanos
- Neurophysiology Laboratory, Physiology Unit, Department of Biomedicine, Medical School, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
| | - Xavier Gasull
- Neurophysiology Laboratory, Physiology Unit, Department of Biomedicine, Medical School, Institute of Neurosciences, University of Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Núria Comes
- Neurophysiology Laboratory, Physiology Unit, Department of Biomedicine, Medical School, Institute of Neurosciences, University of Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
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7
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Jepps TA. Kv7 channel trafficking by the microtubule network in vascular smooth muscle. Acta Physiol (Oxf) 2021; 232:e13692. [PMID: 34021973 PMCID: PMC8365713 DOI: 10.1111/apha.13692] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 05/17/2021] [Accepted: 05/19/2021] [Indexed: 12/17/2022]
Abstract
In arterial smooth muscle cells, changes in availability of integral membrane proteins influence the regulation of blood flow and blood pressure, which is critical for human health. However, the mechanisms that coordinate the trafficking and membrane expression of specific receptors and ion channels in vascular smooth muscle are poorly understood. In the vasculature, very little is known about microtubules, which form a road network upon which proteins can be transported to and from the cell membrane. This review article summarizes the impact of the microtubule network on arterial contractility, highlighting the importance of the network, with an emphasis on our recent findings regarding the trafficking of the voltage‐dependent Kv7 channels.
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Affiliation(s)
- Thomas A Jepps
- Vascular Biology Group Department of Biomedical Sciences University of Copenhagen Blegdamsvej 3 2200 Copenhagen N Denmark
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8
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van der Horst J, Rognant S, Abbott GW, Ozhathil LC, Hägglund P, Barrese V, Chuang CY, Jespersen T, Davies MJ, Greenwood IA, Gourdon P, Aalkjær C, Jepps TA. Dynein regulates Kv7.4 channel trafficking from the cell membrane. J Gen Physiol 2021; 153:211752. [PMID: 33533890 PMCID: PMC7863719 DOI: 10.1085/jgp.202012760] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/21/2020] [Accepted: 01/08/2021] [Indexed: 12/15/2022] Open
Abstract
The dynein motor protein transports proteins away from the cell membrane along the microtubule network. Recently, we found the microtubule network was important for regulating the membrane abundance of voltage-gated Kv7.4 potassium channels in vascular smooth muscle. Here, we aimed to investigate the influence of dynein on the microtubule-dependent internalization of the Kv7.4 channel. Patch-clamp recordings from HEK293B cells showed Kv7.4 currents were increased after inhibiting dynein function with ciliobrevin D or by coexpressing p50/dynamitin, which specifically interferes with dynein motor function. Mutation of a dynein-binding site in the Kv7.4 C terminus increased the Kv7.4 current and prevented p50 interference. Structured illumination microscopy, proximity ligation assays, and coimmunoprecipitation showed colocalization of Kv7.4 and dynein in mesenteric artery myocytes. Ciliobrevin D enhanced mesenteric artery relaxation to activators of Kv7.2–Kv7.5 channels and increased membrane abundance of Kv7.4 protein in isolated smooth muscle cells and HEK293B cells. Ciliobrevin D failed to enhance the negligible S-1–mediated relaxations after morpholino-mediated knockdown of Kv7.4. Mass spectrometry revealed an interaction of dynein with caveolin-1, confirmed using proximity ligation and coimmunoprecipitation assays, which also provided evidence for interaction of caveolin-1 with Kv7.4, confirming that Kv7.4 channels are localized to caveolae in mesenteric artery myocytes. Lastly, cholesterol depletion reduced the interaction of Kv7.4 with caveolin-1 and dynein while increasing the overall membrane expression of Kv7.4, although it attenuated the Kv7.4 current in oocytes and interfered with the action of ciliobrevin D and channel activators in arterial segments. Overall, this study shows that dynein can traffic Kv7.4 channels in vascular smooth muscle in a mechanism dependent on cholesterol-rich caveolae.
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Affiliation(s)
| | - Salomé Rognant
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA
| | | | - Per Hägglund
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Vincenzo Barrese
- St. George's, University of London, London, UK.,Department of Neuroscience, Reproductive Science and Dentistry, University of Naples "Federico II," Naples, Italy
| | - Christine Y Chuang
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Jespersen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Medical Sciences, Lund University, Lund, Sweden
| | - Christian Aalkjær
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Thomas A Jepps
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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9
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Baldwin SN, Sandow SL, Mondéjar-Parreño G, Stott JB, Greenwood IA. K V7 Channel Expression and Function Within Rat Mesenteric Endothelial Cells. Front Physiol 2020; 11:598779. [PMID: 33364977 PMCID: PMC7750541 DOI: 10.3389/fphys.2020.598779] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 11/13/2020] [Indexed: 01/04/2023] Open
Abstract
Background and Purpose: Arterial diameter is dictated by the contractile state of the vascular smooth muscle cells (VSMCs), which is modulated by direct and indirect inputs from endothelial cells (ECs). Modulators of KCNQ-encoded kV7 channels have considerable impact on arterial diameter and these channels are known to be expressed in VSMCs but not yet defined in ECs. However, expression of kV7 channels in ECs would add an extra level of vascular control. This study aims to characterize the expression and function of KV7 channels within rat mesenteric artery ECs. Experimental Approach: In rat mesenteric artery, KCNQ transcript and KV7 channel protein expression were determined via RT-qPCR, immunocytochemistry, immunohistochemistry and immunoelectron microscopy. Wire myography was used to determine vascular reactivity. Key Results: KCNQ transcript was identified in isolated ECs and VSMCs. KV7.1, KV7.4 and KV7.5 protein expression was determined in both isolated EC and VSMC and in whole vessels. Removal of ECs attenuated vasorelaxation to two structurally different KV7.2-5 activators S-1 and ML213. KIR2 blockers ML133, and BaCl2 also attenuated S-1 or ML213-mediated vasorelaxation in an endothelium-dependent process. KV7 inhibition attenuated receptor-dependent nitric oxide (NO)-mediated vasorelaxation to carbachol, but had no impact on relaxation to the NO donor, SNP. Conclusion and Implications: In rat mesenteric artery ECs, KV7.4 and KV7.5 channels are expressed, functionally interact with endothelial KIR2.x channels and contribute to endogenous eNOS-mediated relaxation. This study identifies KV7 channels as novel functional channels within rat mesenteric ECs and suggests that these channels are involved in NO release from the endothelium of these vessels.
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Affiliation(s)
- Samuel N Baldwin
- Vascular Biology Research Centre, Institute of Molecular and Clinical Sciences, St George's University of London, London, United Kingdom
| | - Shaun L Sandow
- Biomedical Science, School of Health and Sports Science, University of the Sunshine Coast, Maroochydore, QLD, Australia
| | - Gema Mondéjar-Parreño
- Department of Pharmacology and Toxicology, School of Medicine, Complutense University of Madrid, Madrid, Spain
| | - Jennifer B Stott
- Vascular Biology Research Centre, Institute of Molecular and Clinical Sciences, St George's University of London, London, United Kingdom
| | - Iain A Greenwood
- Vascular Biology Research Centre, Institute of Molecular and Clinical Sciences, St George's University of London, London, United Kingdom
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10
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Wray S, Arrowsmith S. Uterine Excitability and Ion Channels and Their Changes with Gestation and Hormonal Environment. Annu Rev Physiol 2020; 83:331-357. [PMID: 33158376 DOI: 10.1146/annurev-physiol-032420-035509] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We address advances in the understanding of myometrial physiology, focusing on excitation and the effects of gestation on ion channels and their relevance to labor. This review moves through pioneering studies to exciting new findings. We begin with the myometrium and its myocytes and describe how excitation might initiate and spread in this myogenic smooth muscle. We then review each of the ion channels in the myometrium: L- and T-type Ca2+ channels, KATP (Kir6) channels, voltage-dependent K channels (Kv4, Kv7, and Kv11), twin-pore domain K channels (TASK, TREK), inward rectifier Kir7.1, Ca2+-activated K+ channels with large (KCNMA1, Slo1), small (KCNN1-3), and intermediate (KCNN4) conductance, Na-activated K channels (Slo2), voltage-gated (SCN) Na+ and Na+ leak channels, nonselective (NALCN) channels, the Na K-ATPase, and hyperpolarization-activated cation channels. We finish by assessing how three key hormones- oxytocin, estrogen, and progesterone-modulate and integrate excitability throughout gestation.
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Affiliation(s)
- Susan Wray
- Department of Women's and Children's Health, University of Liverpool, Liverpool L69 3BX, United Kingdom;
| | - Sarah Arrowsmith
- Department of Women's and Children's Health, University of Liverpool, Liverpool L69 3BX, United Kingdom;
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11
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Serrano-Novillo C, Oliveras A, Ferreres JC, Condom E, Felipe A. Remodeling of Kv7.1 and Kv7.5 Expression in Vascular Tumors. Int J Mol Sci 2020; 21:ijms21176019. [PMID: 32825637 PMCID: PMC7503939 DOI: 10.3390/ijms21176019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/11/2020] [Accepted: 08/18/2020] [Indexed: 12/16/2022] Open
Abstract
Voltage-dependent potassium (Kv) channels contribute to the excitability of nerves and muscles. In addition, Kv participates in several cell functions, including cell cycle progression and proliferation. Kv channel remodeling has been associated with neoplastic cell growth and cancer. Kv7 channels are expressed in blood vessels, and they participate in the maintenance of vascular tone and are implicated in myocyte proliferation. Although evidence links Kv7 remodeling to different types of cancer, its expression in vascular tumors has never been studied. Endothelium-derived vascular neoplasms range from indolent lesions to highly aggressive and metastasizing cancers. Here, we show that Kv7.1 and Kv7.5 are evenly distributed in tunicas as well as the endothelium of healthy veins and arteries. The layered structure of vessels is lost in vascular tumors. By studying eight vascular tumors with different origins and characteristics, we found that Kv7.1 and Kv7.5 expression was changed in vascular cancers. While both channels were generally downregulated, Kv7.5 expression was clearly correlated with neoplastic malignancy. The vascular tumors did not contract; therefore, the role of Kv7 channels is probably related to proliferation rather than controlling vascular tone. Our results identify vascular Kv7 channels as targets for cancer detection and anticancer therapies.
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Affiliation(s)
- Clara Serrano-Novillo
- Molecular Physiology Laboratory, Department de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (C.S.-N.); (A.O.)
| | - Anna Oliveras
- Molecular Physiology Laboratory, Department de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (C.S.-N.); (A.O.)
| | - Joan Carles Ferreres
- Consorci Corporació Sanitària Parc Taulí-Parc Taulí Hospital Universitari, Universitat Autónoma de Barcelona, 08208 Sabadell, Spain;
| | - Enric Condom
- Institut d’Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Universitari de Bellvitge, 08907 L’Hospitalet de Llobregat, Spain;
| | - Antonio Felipe
- Molecular Physiology Laboratory, Department de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain; (C.S.-N.); (A.O.)
- Departament de Bioquímica i Biomedicina Molecular, Universitat de Barcelona, Avda. Diagonal 643, 08028 Barcelona, Spain
- Correspondence: ; Tel.: +34-934034616; Fax: +34-934021559
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12
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van der Horst J, Greenwood IA, Jepps TA. Cyclic AMP-Dependent Regulation of Kv7 Voltage-Gated Potassium Channels. Front Physiol 2020; 11:727. [PMID: 32695022 PMCID: PMC7338754 DOI: 10.3389/fphys.2020.00727] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/04/2020] [Indexed: 01/08/2023] Open
Abstract
Voltage-gated Kv7 potassium channels, encoded by KCNQ genes, have major physiological impacts cardiac myocytes, neurons, epithelial cells, and smooth muscle cells. Cyclic adenosine monophosphate (cAMP), a well-known intracellular secondary messenger, can activate numerous downstream effector proteins, generating downstream signaling pathways that regulate many functions in cells. A role for cAMP in ion channel regulation has been established, and recent findings show that cAMP signaling plays a role in Kv7 channel regulation. Although cAMP signaling is recognized to regulate Kv7 channels, the precise molecular mechanism behind the cAMP-dependent regulation of Kv7 channels is complex. This review will summarize recent research findings that support the mechanisms of cAMP-dependent regulation of Kv7 channels.
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Affiliation(s)
- Jennifer van der Horst
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Iain A Greenwood
- Molecular and Clinical Sciences Institute, St. George's University of London, London, United Kingdom
| | - Thomas A Jepps
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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13
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Mondejar-Parreño G, Perez-Vizcaino F, Cogolludo A. Kv7 Channels in Lung Diseases. Front Physiol 2020; 11:634. [PMID: 32676036 PMCID: PMC7333540 DOI: 10.3389/fphys.2020.00634] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 05/18/2020] [Indexed: 12/23/2022] Open
Abstract
Lung diseases constitute a global health concern causing disability. According to WHO in 2016, respiratory diseases accounted for 24% of world population mortality, the second cause of death after cardiovascular diseases. The Kv7 channels family is a group of voltage-dependent K+ channels (Kv) encoded by KCNQ genes that are involved in various physiological functions in numerous cell types, especially, cardiac myocytes, smooth muscle cells, neurons, and epithelial cells. Kv7 channel α-subunits are regulated by KCNE1–5 ancillary β-subunits, which modulate several characteristics of Kv7 channels such as biophysical properties, cell-location, channel trafficking, and pharmacological sensitivity. Kv7 channels are mainly expressed in two large groups of lung tissues: pulmonary arteries (PAs) and bronchial tubes. In PA, Kv7 channels are expressed in pulmonary artery smooth muscle cells (PASMCs); while in the airway (trachea, bronchus, and bronchioles), Kv7 channels are expressed in airway smooth muscle cells (ASMCs), airway epithelial cells (AEPs), and vagal airway C-fibers (VACFs). The functional role of Kv7 channels may vary depending on the cell type. Several studies have demonstrated that the impairment of Kv7 channel has a strong impact on pulmonary physiology contributing to the pathophysiology of different respiratory diseases such as cystic fibrosis, asthma, chronic obstructive pulmonary disease, chronic coughing, lung cancer, and pulmonary hypertension. Kv7 channels are now recognized as playing relevant physiological roles in many tissues, which have encouraged the search for Kv7 channel modulators with potential therapeutic use in many diseases including those affecting the lung. Modulation of Kv7 channels has been proposed to provide beneficial effects in a number of lung conditions. Therefore, Kv7 channel openers/enhancers or drugs acting partly through these channels have been proposed as bronchodilators, expectorants, antitussives, chemotherapeutics and pulmonary vasodilators.
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Affiliation(s)
- Gema Mondejar-Parreño
- Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain.,Ciber Enfermedades Respiratorias (Ciberes), Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain
| | - Francisco Perez-Vizcaino
- Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain.,Ciber Enfermedades Respiratorias (Ciberes), Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain
| | - Angel Cogolludo
- Departamento de Farmacología y Toxicología, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain.,Ciber Enfermedades Respiratorias (Ciberes), Madrid, Spain.,Instituto de Investigación Sanitaria Gregorio Marañón (IISGM), Madrid, Spain
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14
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Oliveras A, Serrano-Novillo C, Moreno C, de la Cruz A, Valenzuela C, Soeller C, Comes N, Felipe A. The unconventional biogenesis of Kv7.1-KCNE1 complexes. SCIENCE ADVANCES 2020; 6:eaay4472. [PMID: 32270035 PMCID: PMC7112945 DOI: 10.1126/sciadv.aay4472] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 01/09/2020] [Indexed: 06/11/2023]
Abstract
The potassium channel Kv7.1 associates with the KCNE1 regulatory subunit to trigger cardiac I Ks currents. Although the Kv7.1/KCNE1 complex has received much attention, the subcellular compartment hosting the assembly is the subject of ongoing debate. Evidence suggests that the complex forms either earlier in the endoplasmic reticulum or directly at the plasma membrane. Kv7.1 and KCNE1 mutations, responsible for long QT syndromes, impair association and traffic, thereby altering I Ks currents. We found that Kv7.1 and KCNE1 do not assemble in the first stages of their biogenesis. Data support an unconventional secretory pathway for Kv7.1-KCNE1 that bypasses Golgi. This route targets channels to endoplasmic reticulum-plasma membrane junctions, where Kv7.1-KCNE1 assemble. This mechanism helps to resolve the ongoing controversy about the subcellular compartment hosting the association. Our results also provide new insights into I Ks channel localization at endoplasmic reticulum-plasma membrane junctions, highlighting an alternative anterograde trafficking mechanism for oligomeric ion channels.
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Affiliation(s)
- Anna Oliveras
- Molecular Physiology Laboratory, Departamento de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Clara Serrano-Novillo
- Molecular Physiology Laboratory, Departamento de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Cristina Moreno
- National Institute of Neurological Disorders and Stroke (NIH), Bethesda, MD, USA
| | - Alicia de la Cruz
- Instituto de Investigaciones Biomédicas Alberto Sols CSIC-UAM, Madrid, Spain
| | - Carmen Valenzuela
- Instituto de Investigaciones Biomédicas Alberto Sols CSIC-UAM, Madrid, Spain
- Spanish Network for Biomedical Research in Cardiovascular Research (CIBERCV), Instituto de Salud Carlos III, Madrid, Spain
| | - Christian Soeller
- Living Systems Institute and Biomedical Physics, University of Exeter, Exeter, UK
| | - Núria Comes
- Departamento De Biomedicina, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
| | - Antonio Felipe
- Molecular Physiology Laboratory, Departamento de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
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15
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Mondéjar-Parreño G, Moral-Sanz J, Barreira B, De la Cruz A, Gonzalez T, Callejo M, Esquivel-Ruiz S, Morales-Cano D, Moreno L, Valenzuela C, Perez-Vizcaino F, Cogolludo A. Activation of K v 7 channels as a novel mechanism for NO/cGMP-induced pulmonary vasodilation. Br J Pharmacol 2019; 176:2131-2145. [PMID: 30883701 DOI: 10.1111/bph.14662] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 02/08/2019] [Accepted: 02/13/2019] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND AND PURPOSE The NO/cGMP pathway represents a major physiological signalling controlling tone in pulmonary arteries (PA), and drugs activating this pathway are used to treat pulmonary arterial hypertension. Kv channels expressed in PA smooth muscle cells (PASMCs) are key determinants of vascular tone. We aimed to analyse the contribution of Kv 1.5 and Kv 7 channels in the electrophysiological and vasodilating effects evoked by NO donors and the GC stimulator riociguat in PA. EXPERIMENTAL APPROACH Kv currents were recorded in isolated rat PASMCs using the patch-clamp technique. Vascular reactivity was assessed in a wire myograph. KEY RESULTS The NO donors diethylamine NONOate diethylammonium (DEA-NO) and sodium nitroprusside hyperpolarized the membrane potential and induced a bimodal effect on Kv currents (augmenting the current between -40 and -10 mV and decreasing it at more depolarized potentials). The hyperpolarization and the enhancement of the current were suppressed by Kv 7 channel inhibitors and by the GC inhibitor ODQ but preserved when Kv 1.5 channels were inhibited. Additionally, DEA-NO enhanced Kv 7.5 currents in COS7 cells expressing the KCNQ5 gene. Riociguat increased Kv currents at all potentials ≥-40 mV and induced membrane hyperpolarization. Both effects were prevented by Kv 7 inhibition. Likewise, PA relaxation induced by NO donors and riociguat was attenuated by Kv 7 inhibitors. CONCLUSIONS AND IMPLICATIONS NO donors and riociguat enhance Kv 7 currents, leading to PASMC hyperpolarization. This mechanism contributes to NO/cGMP-induced PA vasodilation. Our study identifies Kv 7 channels as a novel mechanism of action of vasodilator drugs used in the treatment of pulmonary arterial hypertension.
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Affiliation(s)
- Gema Mondéjar-Parreño
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Javier Moral-Sanz
- Centres for Discovery Brain Sciences and Cardiovascular Science, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, UK
| | - Bianca Barreira
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Alicia De la Cruz
- Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-UAM, Madrid, Spain.,CIBER Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Teresa Gonzalez
- Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-UAM, Madrid, Spain.,CIBER Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain.,Department of Biochemistry, School of Medicine, Universidad Autónoma de Madrid, Hospital La Paz Institute for Health Research (IdiPAZ), Madrid, Spain
| | - Maria Callejo
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Sergio Esquivel-Ruiz
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Daniel Morales-Cano
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Laura Moreno
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Carmen Valenzuela
- Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-UAM, Madrid, Spain.,CIBER Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Francisco Perez-Vizcaino
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Angel Cogolludo
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
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16
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Gollasch M, Welsh DG, Schubert R. Perivascular adipose tissue and the dynamic regulation of K v 7 and K ir channels: Implications for resistant hypertension. Microcirculation 2018; 25. [PMID: 29211322 DOI: 10.1111/micc.12434] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/30/2017] [Indexed: 12/20/2022]
Abstract
Resistant hypertension is defined as high blood pressure that remains uncontrolled despite treatment with at least three antihypertensive drugs at adequate doses. Resistant hypertension is an increasingly common clinical problem in older age, obesity, diabetes, sleep apnea, and chronic kidney disease. Although the direct vasodilator minoxidil was introduced in the early 1970s, only recently has this drug been shown to be particularly effective in a subgroup of patients with treatment-resistant or uncontrolled hypertension. This pharmacological approach is interesting from a mechanistic perspective as minoxidil is the only clinically used K+ channel opener today, which targets a subclass of K+ channels, namely KATP channels in VSMCs. Beside KATP channels, two other classes of VSMC K+ channels could represent novel effective targets for treatment of resistant hypertension, namely Kv 7 (KCNQ) and inward rectifier potassium (Kir 2.1) channels. Interestingly, these channels are unique among VSMC potassium channels. First, both have been implicated in the control of microvascular tone by perivascular adipose tissue. Second, they exhibit biophysical properties strongly controlled and regulated by membrane voltage, but not intracellular calcium. This review focuses on Kv 7 (Kv 7.1-5) and Kir (Kir 2.1) channels in VSMCs as potential novel drug targets for treatment of resistant hypertension, particularly in comorbid conditions such as obesity and metabolic syndrome.
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Affiliation(s)
- Maik Gollasch
- Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum, Experimental and Clinical Research Center (ECRC) - a joint cooperation between the Charité - University Medicine Berlin and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Donald G Welsh
- Department of Physiology and Pharmacology, Western University, London, ON, Canada
| | - Rudolf Schubert
- Centre for Biomedicine and Medical Technology Mannheim (CBTM), Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
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17
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Mechanisms of PKA-Dependent Potentiation of Kv7.5 Channel Activity in Human Airway Smooth Muscle Cells. Int J Mol Sci 2018; 19:ijms19082223. [PMID: 30061510 PMCID: PMC6121446 DOI: 10.3390/ijms19082223] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 07/26/2018] [Accepted: 07/27/2018] [Indexed: 12/18/2022] Open
Abstract
β-adrenergic receptor (βAR) activation promotes relaxation of both vascular and airway smooth muscle cells (VSMCs and ASMCs, respectively), though the signaling mechanisms have not been fully elucidated. We previously found that the activity of Kv7.5 voltage-activated potassium channels in VSMCs is robustly enhanced by activation of βARs via a mechanism involving protein kinase A (PKA)-dependent phosphorylation. We also found that enhancement of Kv7 channel activity in ASMCs promotes airway relaxation. Here we provide evidence that Kv7.5 channels are natively expressed in primary cultures of human ASMCs and that they conduct currents which are robustly enhanced in response to activation of the βAR/cyclic adenosine monophosphate (cAMP)/PKA pathway. MIT Scansite software analysis of putative PKA phosphorylation sites on Kv7.5 identified 8 candidate serine or threonine residues. Each residue was individually mutated to an alanine to prevent its phosphorylation and then tested for responses to βAR activation or to stimuli that elevate cAMP levels. Only the mutation of serine 53 (S53A), located on the amino terminus of Kv7.5, significantly reduced the increase in Kv7.5 current in response to these stimuli. A phospho-mimic mutation (S53D) exhibited characteristics of βAR-activated Kv7.5. Serine-to-alanine mutations of 6 putative PKA phosphorylation sites on the Kv7.5 C-terminus, individually or in combination, did not significantly reduce the enhancement of the currents in response to forskolin treatment (to elevate cAMP levels). We conclude that phosphorylation of S53 on the amino terminus of Kv7.5 is essential for PKA-dependent enhancement of channel activity in response to βAR activation in vascular and airway smooth muscle cells.
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18
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Activation of PPARβ/δ prevents hyperglycaemia-induced impairment of Kv7 channels and cAMP-mediated relaxation in rat coronary arteries. Clin Sci (Lond) 2016; 130:1823-36. [PMID: 27413020 DOI: 10.1042/cs20160141] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 07/13/2016] [Indexed: 01/09/2023]
Abstract
PPARβ/δ activation protects against endothelial dysfunction in diabetic models. Elevated glucose is known to impair cAMP-induced relaxation and Kv channel function in coronary arteries (CA). Herein, we aimed to analyse the possible protective effects of the PPARβ/δ agonist GW0742 on the hyperglycaemic-induced impairment of cAMP-induced relaxation and Kv channel function in rat CA. As compared with low glucose (LG), incubation under high glucose (HG) conditions attenuated the relaxation induced by the adenylate cyclase activator forskolin in CA and this was prevented by GW0742. The protective effect of GW0742 was supressed by a PPARβ/δ antagonist. In myocytes isolated from CA under LG, forskolin enhanced Kv currents and induced hyperpolarization. In contrast, when CA were incubated with HG, Kv currents were diminished and the electrophysiological effects of forskolin were abolished. These deleterious effects were prevented by GW0742. The protective effects of GW0742 on forskolin-induced relaxation and Kv channel function were confirmed in CA from type-1 diabetic rats. In addition, the differences in the relaxation induced by forskolin in CA incubated under LG, HG or HG + GW0742 were abolished by the Kv7 channel inhibitor XE991. Accordingly, GW0742 prevented the down-regulation of Kv7 channels induced by HG. Finally, the preventive effect of GW0742 on oxidative stress and cAMP-induced relaxation were overcome by the pyruvate dehydrogenase kinase 4 (PDK4) inhibitor dichloroacetate (DCA). Our results reveal that the PPARβ/δ agonist GW0742 prevents the impairment of the cAMP-mediated relaxation in CA under HG. This protective effect was associated with induction of PDK4, attenuation of oxidative stress and preservation of Kv7 channel function.
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19
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Haick JM, Byron KL. Novel treatment strategies for smooth muscle disorders: Targeting Kv7 potassium channels. Pharmacol Ther 2016; 165:14-25. [PMID: 27179745 DOI: 10.1016/j.pharmthera.2016.05.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Smooth muscle cells provide crucial contractile functions in visceral, vascular, and lung tissues. The contractile state of smooth muscle is largely determined by their electrical excitability, which is in turn influenced by the activity of potassium channels. The activity of potassium channels sustains smooth muscle cell membrane hyperpolarization, reducing cellular excitability and thereby promoting smooth muscle relaxation. Research over the past decade has indicated an important role for Kv7 (KCNQ) voltage-gated potassium channels in the regulation of the excitability of smooth muscle cells. Expression of multiple Kv7 channel subtypes has been demonstrated in smooth muscle cells from viscera (gastrointestinal, bladder, myometrial), from the systemic and pulmonary vasculature, and from the airways of the lung, from multiple species, including humans. A number of clinically used drugs, some of which were developed to target Kv7 channels in other tissues, have been found to exert robust effects on smooth muscle Kv7 channels. Functional studies have indicated that Kv7 channel activators and inhibitors have the ability to relax and contact smooth muscle preparations, respectively, suggesting a wide range of novel applications for the pharmacological tool set. This review summarizes recent findings regarding the physiological functions of Kv7 channels in smooth muscle, and highlights potential therapeutic applications based on pharmacological targeting of smooth muscle Kv7 channels throughout the body.
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Affiliation(s)
- Jennifer M Haick
- Department of Molecular Pharmacology & Therapeutics, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
| | - Kenneth L Byron
- Department of Molecular Pharmacology & Therapeutics, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA.
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20
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Goodwill AG, Fu L, Noblet JN, Casalini ED, Sassoon D, Berwick ZC, Kassab GS, Tune JD, Dick GM. KV7 channels contribute to paracrine, but not metabolic or ischemic, regulation of coronary vascular reactivity in swine. Am J Physiol Heart Circ Physiol 2016; 310:H693-704. [PMID: 26825518 DOI: 10.1152/ajpheart.00688.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 01/20/2016] [Indexed: 12/30/2022]
Abstract
Hydrogen peroxide (H2O2) and voltage-dependent K(+) (KV) channels play key roles in regulating coronary blood flow in response to metabolic, ischemic, and paracrine stimuli. The KV channels responsible have not been identified, but KV7 channels are possible candidates. Existing data regarding KV7 channel function in the coronary circulation (limited to ex vivo assessments) are mixed. Thus we examined the hypothesis that KV7 channels are present in cells of the coronary vascular wall and regulate vasodilation in swine. We performed a variety of molecular, biochemical, and functional (in vivo and ex vivo) studies. Coronary arteries expressed KCNQ genes (quantitative PCR) and KV7.4 protein (Western blot). Immunostaining demonstrated KV7.4 expression in conduit and resistance vessels, perhaps most prominently in the endothelial and adventitial layers. Flupirtine, a KV7 opener, relaxed coronary artery rings, and this was attenuated by linopirdine, a KV7 blocker. Endothelial denudation inhibited the flupirtine-induced and linopirdine-sensitive relaxation of coronary artery rings. Moreover, linopirdine diminished bradykinin-induced endothelial-dependent relaxation of coronary artery rings. There was no effect of intracoronary flupirtine or linopirdine on coronary blood flow at the resting heart rate in vivo. Linopirdine had no effect on coronary vasodilation in vivo elicited by ischemia, H2O2, or tachycardia. However, bradykinin increased coronary blood flow in vivo, and this was attenuated by linopirdine. These data indicate that KV7 channels are expressed in some coronary cell type(s) and influence endothelial function. Other physiological functions of coronary vascular KV7 channels remain unclear, but they do appear to contribute to endothelium-dependent responses to paracrine stimuli.
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Affiliation(s)
- Adam G Goodwill
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana; and
| | - Lijuan Fu
- California Medical Innovations Institute, San Diego, California
| | - Jillian N Noblet
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana; and
| | - Eli D Casalini
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana; and
| | - Daniel Sassoon
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana; and
| | | | | | - Johnathan D Tune
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana; and
| | - Gregory M Dick
- California Medical Innovations Institute, San Diego, California
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21
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Nekouzadeh A, Rudy Y. Conformational changes of an ion-channel during gating and emerging electrophysiologic properties: Application of a computational approach to cardiac Kv7.1. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 120:18-27. [PMID: 26743208 DOI: 10.1016/j.pbiomolbio.2015.12.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 12/23/2015] [Accepted: 12/28/2015] [Indexed: 10/22/2022]
Abstract
Ion channels are the "building blocks" of the excitation process in excitable tissues. Despite advances in determining their molecular structure, understanding the relationship between channel protein structure and electrical excitation remains a challenge. The Kv7.1 potassium channel is an important determinant of the cardiac action potential and its adaptation to rate changes. It is subject to beta adrenergic regulation, and many mutations in the channel protein are associated with the arrhythmic long QT syndrome. In this theoretical study, we use a novel computational approach to simulate the conformational changes that Kv7.1 undergoes during activation gating and compute the resulting electrophysiologic function in terms of single-channel and macroscopic currents. We generated all possible conformations of the S4-S5 linker that couples the S3-S4 complex (voltage sensor domain, VSD) to the pore, and all associated conformations of VSD and the pore (S6). Analysis of these conformations revealed that VSD-to-pore mechanical coupling during activation gating involves outward translation of the voltage sensor, accompanied by a translation away from the pore and clockwise twist. These motions cause pore opening by moving the S4-S5 linker upward and away from the pore, providing space for the S6 tails to move away from each other. Single channel records, computed from the simulated motion trajectories during gating, have stochastic properties similar to experimentally recorded traces. Macroscopic current through an ensemble of channels displays two key properties of Kv7.1: an initial delay of activation and fast inactivation. The simulations suggest a molecular mechanism for fast inactivation; a large twist of the VSD following its outward translation results in movement of the base of the S4-S5 linker toward the pore, eliminating open pore conformations to cause inactivation.
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Affiliation(s)
- Ali Nekouzadeh
- Cardiac Bioelectricity and Arrhythmia Center and Departments of Biomedical Engineering and Cell Biology & Physiology, Washington University in St. Louis, 290 Whitaker Hall, 1 Brooking Dr., St. Louis, MO 63130, USA.
| | - Yoram Rudy
- Cardiac Bioelectricity and Arrhythmia Center and Departments of Biomedical Engineering and Cell Biology & Physiology, Washington University in St. Louis, 290 Whitaker Hall, 1 Brooking Dr., St. Louis, MO 63130, USA.
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22
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Mani BK, Robakowski C, Brueggemann LI, Cribbs LL, Tripathi A, Majetschak M, Byron KL. Kv7.5 Potassium Channel Subunits Are the Primary Targets for PKA-Dependent Enhancement of Vascular Smooth Muscle Kv7 Currents. Mol Pharmacol 2015; 89:323-34. [PMID: 26700561 DOI: 10.1124/mol.115.101758] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 12/18/2015] [Indexed: 12/11/2022] Open
Abstract
Kv7 (KCNQ) channels, formed as homo- or heterotetramers of Kv7.4 and Kv7.5 α-subunits, are important regulators of vascular smooth muscle cell (VSMC) membrane voltage. Recent studies demonstrate that direct pharmacological modulation of VSMC Kv7 channel activity can influence blood vessel contractility and diameter. However, the physiologic regulation of Kv7 channel activity is still poorly understood. Here, we study the effect of cAMP/protein kinase A (PKA) activation on whole cell K(+) currents through endogenous Kv7.5 channels in A7r5 rat aortic smooth muscle cells or through Kv7.4/Kv7.5 heteromeric channels natively expressed in rat mesenteric artery smooth muscle cells. The contributions of specific α-subunits are further dissected using exogenously expressed human Kv7.4 and Kv7.5 homo- or heterotetrameric channels in A7r5 cells. Stimulation of Gαs-coupled β-adrenergic receptors with isoproterenol induced PKA-dependent activation of endogenous Kv7.5 currents in A7r5 cells. The receptor-mediated enhancement of Kv7.5 currents was mimicked by pharmacological agents that increase [cAMP] (forskolin, rolipram, 3-isobutyl-1-methylxanthine, and papaverine) or mimic cAMP (8-bromo-cAMP); the 2- to 4-fold PKA-dependent enhancement of currents was also observed with exogenously expressed Kv7.5 channels. In contrast, exogenously-expressed heterotetrameric Kv7.4/7.5 channels in A7r5 cells or native mesenteric artery smooth muscle Kv7.4/7.5 channels were only modestly enhanced, and homo-tetrameric Kv7.4 channels were insensitive to this regulatory pathway. Correspondingly, proximity ligation assays indicated that isoproterenol induced PKA-dependent phosphorylation of exogenously expressed Kv7.5 channel subunits, but not of Kv7.4 subunits. These results suggest that signal transduction-mediated responsiveness of vascular smooth muscle Kv7 channel subunits to cAMP/PKA activation follows the order of Kv7.5 >> Kv7.4/Kv7.5 > Kv7.4.
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Affiliation(s)
- Bharath K Mani
- Department of Molecular Pharmacology and Therapeutics (B.K.M., C.R., L.I.B., M.M., K.L.B.), Department of Cell and Molecular Physiology (L.L.C.), and Department of Surgery (A.T., M.M.), Loyola University Chicago, Maywood, Illinois
| | - Christina Robakowski
- Department of Molecular Pharmacology and Therapeutics (B.K.M., C.R., L.I.B., M.M., K.L.B.), Department of Cell and Molecular Physiology (L.L.C.), and Department of Surgery (A.T., M.M.), Loyola University Chicago, Maywood, Illinois
| | - Lyubov I Brueggemann
- Department of Molecular Pharmacology and Therapeutics (B.K.M., C.R., L.I.B., M.M., K.L.B.), Department of Cell and Molecular Physiology (L.L.C.), and Department of Surgery (A.T., M.M.), Loyola University Chicago, Maywood, Illinois
| | - Leanne L Cribbs
- Department of Molecular Pharmacology and Therapeutics (B.K.M., C.R., L.I.B., M.M., K.L.B.), Department of Cell and Molecular Physiology (L.L.C.), and Department of Surgery (A.T., M.M.), Loyola University Chicago, Maywood, Illinois
| | - Abhishek Tripathi
- Department of Molecular Pharmacology and Therapeutics (B.K.M., C.R., L.I.B., M.M., K.L.B.), Department of Cell and Molecular Physiology (L.L.C.), and Department of Surgery (A.T., M.M.), Loyola University Chicago, Maywood, Illinois
| | - Matthias Majetschak
- Department of Molecular Pharmacology and Therapeutics (B.K.M., C.R., L.I.B., M.M., K.L.B.), Department of Cell and Molecular Physiology (L.L.C.), and Department of Surgery (A.T., M.M.), Loyola University Chicago, Maywood, Illinois
| | - Kenneth L Byron
- Department of Molecular Pharmacology and Therapeutics (B.K.M., C.R., L.I.B., M.M., K.L.B.), Department of Cell and Molecular Physiology (L.L.C.), and Department of Surgery (A.T., M.M.), Loyola University Chicago, Maywood, Illinois
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23
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Zhang W, Wang H, Guan X, Niu Q, Li W. Variant rs2237892 of KCNQ1 Is Potentially Associated with Hypertension and Macrovascular Complications in Type 2 Diabetes Mellitus in A Chinese Han Population. GENOMICS PROTEOMICS & BIOINFORMATICS 2015; 13:364-70. [PMID: 26678516 PMCID: PMC4747647 DOI: 10.1016/j.gpb.2015.05.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 05/05/2015] [Accepted: 05/26/2015] [Indexed: 01/08/2023]
Abstract
KCNQ1 has been identified as a susceptibility gene of type 2 diabetes mellitus (T2DM) in Asian populations through genome-wide association studies. However, studies on the association between gene polymorphism of KCNQ1 and T2DM complications remain unclear. To further analyze the association between different alleles at the single nucleotide polymorphism (SNP) rs2237892 within KCNQ1 and TD2M and its complications, we conducted a case-control study in a Chinese Han population. The C allele of rs2237892 variant contributed to susceptibility to T2DM (odds ratio [OR], 1.45; 95% confidence interval [CI], 1.20-1.75). Genotypes CT (OR, 1.97; 95% CI, 1.24-3.15) and CC (OR, 2.49; 95% CI, 1.57-3.95) were associated with an increased risk of T2DM. Multivariate regression analysis was performed with adjustment of age, gender, and body mass index. We found that systolic blood pressure (P=0.015), prevalence of hypertension (P=0.037), and risk of macrovascular disease (OR, 2.10; CI, 1.00-4.45) were significantly higher in subjects with the CC genotype than in the combined population with genotype either CT or TT. Therefore, our data support that KCNQ1 is associated with an increased risk for T2DM and might contribute to the higher incidence of hypertension and macrovascular complications in patients with T2DM carrying the risk allele C though it needs further to be confirmed in a larger population.
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Affiliation(s)
- Wanlin Zhang
- Zhejiang Key Laboratory of Medical Genetics, Wenzhou Medical University, Wenzhou 325035, China
| | - Hailing Wang
- Zhejiang Key Laboratory of Medical Genetics, Wenzhou Medical University, Wenzhou 325035, China
| | - Xiaomin Guan
- Zhejiang Key Laboratory of Medical Genetics, Wenzhou Medical University, Wenzhou 325035, China
| | - Qing Niu
- Zhejiang Key Laboratory of Medical Genetics, Wenzhou Medical University, Wenzhou 325035, China
| | - Wei Li
- Zhejiang Key Laboratory of Medical Genetics, Wenzhou Medical University, Wenzhou 325035, China; School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou 325025, China.
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24
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Morales-Cano D, Moreno L, Barreira B, Pandolfi R, Chamorro V, Jimenez R, Villamor E, Duarte J, Perez-Vizcaino F, Cogolludo A. Kv7 channels critically determine coronary artery reactivity: left-right differences and down-regulation by hyperglycaemia. Cardiovasc Res 2015; 106:98-108. [PMID: 25616413 DOI: 10.1093/cvr/cvv020] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIMS Voltage-gated potassium channels encoded by KCNQ genes (Kv7 channels) are emerging as important regulators of vascular tone. In this study, we analysed the contribution of Kv7 channels to the vasodilation induced by hypoxia and the cyclic AMP pathway in the coronary circulation. We also assessed their regional distribution and possible impairment by diabetes. METHODS AND RESULTS We examined the effects of Kv7 channel modulators on K+ currents and vascular reactivity in rat left and right coronary arteries (LCAs and RCAs, respectively). Currents from LCA were more sensitive to Kv7 channel inhibitors (XE991, linopirdine) and activators (flupirtine, retigabine) than those from RCA. Accordingly, LCAs were more sensitive than RCAs to the relaxation induced by Kv7 channel enhancers. Likewise, relaxation induced by the adenylyl cyclase activator forskolin and hypoxia, which were mediated through Kv7 channel activation, were greater in LCA than in RCA. KCNQ1 and KCNQ5 expression was markedly higher in LCA than in RCA. After incubation with high glucose (HG, 30 mmol/L), myocytes from LCA, but not from RCA, were more depolarized and showed reduced Kv7 currents. In HG-incubated LCA, the effects of Kv7 channel modulators and forskolin were diminished, and the expression of KCNQ1 and KCNQ5 was reduced. Finally, vascular responses induced by Kv7 channel modulators were impaired in LCA, but not in RCA, from type 1 diabetic rats. CONCLUSION Our results reveal that the high expression and function of Kv7 channels in the LCA and their down-regulation by diabetes critically determine the sensitivity to key regulators of coronary tone.
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Affiliation(s)
- Daniel Morales-Cano
- Department of Pharmacology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Ciudad Universitaria S/N, Madrid 28040, Spain Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Laura Moreno
- Department of Pharmacology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Ciudad Universitaria S/N, Madrid 28040, Spain Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Bianca Barreira
- Department of Pharmacology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Ciudad Universitaria S/N, Madrid 28040, Spain Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Rachele Pandolfi
- Department of Pharmacology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Ciudad Universitaria S/N, Madrid 28040, Spain Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Virginia Chamorro
- Department of Pharmacology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Ciudad Universitaria S/N, Madrid 28040, Spain Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Rosario Jimenez
- Department of Pharmacology, School of Pharmacy, University of Granada, Granada 18071, Spain
| | - Eduardo Villamor
- Department of Pediatrics, Maastricht University Medical Center (MUMC+), Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands
| | - Juan Duarte
- Department of Pharmacology, School of Pharmacy, University of Granada, Granada 18071, Spain
| | - Francisco Perez-Vizcaino
- Department of Pharmacology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Ciudad Universitaria S/N, Madrid 28040, Spain Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Angel Cogolludo
- Department of Pharmacology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Ciudad Universitaria S/N, Madrid 28040, Spain Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
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